CA2035575C

CA2035575C - High thermal strength bonding fiber

Info

Publication number: CA2035575C
Application number: CA 2035575
Authority: CA
Inventors: Randall Earl Kozulla
Original assignee: Hercules LLC
Current assignee: FIBERVISIONS LP
Priority date: 1990-02-05
Filing date: 1991-02-01
Publication date: 1996-07-16
Anticipated expiration: 2011-02-01
Also published as: DE69132180D1; BR9100461A; DK0445536T4; FI910471A0; KR910015727A; DE69132180T2; EP0445536B1; FI910471A; US5318735A; JPH04228666A; EP0445536A2; FI112252B; US5281378A; US5431994A; CA2035575A1; ES2144991T5; DK0445536T3; EP0445536B2; JP2908045B2; KR100387546B1

Abstract

High strength spun melt fibre, preparation thereof utilizing threadline oxidative chain scission degradation of hot fibre spun from polymer component(s) having a broad molecular weight distribution in conjunction with a delayed quench step, and corresponding nonwoven material obtained therefrom.

Description

-BACKGROUND

A number of modern uses have been found for nonwoven materials produced from melt spun polymers, particularly degraded polyolefin-containing compositions. SuCh uses, in general, demand special properties of the nonwoven and corresponding fibre such as special fluid handling, high vapour permeability, softness, integrity and durability, as well as efficient cost-effective processing techniques.

Unfortunately, however, the achievement of properties such as softness, and vapour-permeability, for example, present serious largely unanswered technical problems with respect to strength, durability and efficiency of production of the respective staple and nonwoven products.

One particularly troublesome and long standing problem in this general area stems from the fact that efficient, high speed spinning and processing of polyolefin fibre such as polypropylene requires careful control over the degree of chemical degradation and melt flow rate (MFR) of the spun melt, and a highly efficient quenching step capable of avoiding substantial over- or under-quench leading to melt fracture or ductile failure under highspeed commercial manufacturing conditions. The resulting fibre can vary substantially in bonding properties.

It is an object of the present invention to improve control over polymer degradation, spin and quench steps so as to obtain fibre capable of producing nonwoven fabric having increased strength, toughness, and integrity.

It is a further object to improve the heat bonding properties of fibre spun from polyolefin-containing melt such as polypropylene polymer or copolymer.

The above objects are realized by use of the instant process whereby monocomponents or bicomponent fibre having improved heat bonding properties and material strength, elongation, and toughness is obtained by:
A. admixing an effective amount of at least one antioxidant/stabilizer composition into a dry melt spun mixture comprising broad molecular weight distribution polyolefin polymer or copolymer, such as polypropylene as hereafter defined, in the presence of an active amount of a degrading composition, and various other additives known to the spinning art can also be incorporated, as desired, such as pigments and art-known whiteners and colorants such as Tio2 and pH-stabilizing agents such as calcium stearate in usual amounts (i.e., 1%-10% or less);
B. heating and spinning the resulting spun melt mixture, at a temperature, preferably within a range of about 250 C -325 C, and in an environment under sufficient pressure to minimize or control oxidative chain scission degradation of polymeric component(s) within said spun mixture prior to and during said spinning step;
C. taking up the resulting hot (essentially unquenched) spun fibre under an oxygen-containing atmosphere maximizing gas diffusion into the hot fibre to effect threadline oxidative chain scission degradation of the fibre; and D. ~uenching and finishing the resulting partially degraded spun fibre to obtain a raw spun fibre having a highly degraded surface zone of low molecular weight, low birefringence, and a minimally degraded, essentially crystalline birefringent inner configuration, these two zones representing extremes defining an intermediate zone (see below) having a gradation in oxidative degradation depending generally upon fibre structure and rate of diffusion of oxidant into the hot fibre.

The resulting fibre or filament is further characterized as the spun product of a broad molecular weight polyolefin polymer or copolymer, preferably a polypropylene-containing spun melt .~

having incorporated therein an effective amount of at least one antioxidant/stabilizer composition, the resulting fibre or filament, when quenched, comprising, in combination:
(a) an inner zone identified by minimal oxidative polymeric degradation, high birefringence, and a weight average molecular weight within a range of about 100,000-450,000 and preferably about 100,000-250,000;
(b) an intermediate zone generally externally concentric to the inner zone and further identified by progressive (inside-to-outside) oxidative chain scission degradation, the polymeric material within the intermediate zone having a molecular weight gradation within a range of about 100,000-450,000 to less than 20,000 and preferably about 10,000-20,000; and (c) a surface zone generally externally concentric to the intermediate zone and defining the external surface of the fibre or filament, the surface zone being further identified by low birefringence, a high concentration of oxidative chain scission degraded polymeric material, and a weight average molecular weight of less than about 10,000 and preferably about 5,000-10,000.

Further, the characteristics of the inner zone, the surface zone and the graduated intermediate zone can be defined using terminology which is related to the weight average molecular weight. For example, the various zones can be defined using the melt flow rate of the polymer. In this regard, as the molecular weight decreases towards the surface of the fibre, there will be a corresponding increase in the melt flow rate.

For present purposes the term "effective amount", as applied to the concentration of antioxidant/stabilizer compositions within the dry spun melt mixture, is defined as an amount, based on dry weight, which is capable of preventing or at least substantially limiting chain scission degradation of the hot polymeric component(s) within fibre spinning temperature ranges in the substantial absence of oxygen, an oxygen evolving, or an oxygen-containing gas. In particular, it refers to a concentration of one or more antioxidant compositions sufficient to effectively limit chain scission degradation of polyolefin component of a heated spun melt composition within a temperature range of about 250 C to about 325 C, in the substantial absence of an oxidizing environment such as oxygen, air or other oxygen/nitrogen mixtures. The above definition, however, permits a substantial amount of oxygen diffusion and oxidative polymeric degradation to occur, commencing at or about the melt zone of the spun fibre threadline and extending downstream, as far as desired, to a point where natural heat loss and/or an applied quenching environment lowers the fibre surface temperature (to about 250 C or below, in the case of polypropylene polymer or copolymer) to a point where further oxygen diffusion into the spun fibre or filament is negligible.

Generally speaking, the total combined antioxidant/
stabilizer concentration usually falls within a range of about .002%-1% by weight, and preferably within a range of about .005%-0.5%, the exact amount depending on the particular rheological and molecular properties of the chosen broad molecular weight polymeric component(s) and the temperature of the spun melt;
additional parameters are represented by temperature and pressure within the spinnerette itself, and the amount of prior exposure to residual amounts of oxidant such as air while in a heated state upstream of the spinnerette. Below or downstream of the spinnerette an oxygen/nitrogen gas flow ratio of about 100-10 to 0-90 by volume at an ambient temperature up to about 200 C plus a delayed quench step are preferred to assure adequate chain scission degradation of the polymer component and to provide improved thermal bonding characteristics, leading to increased strength, elongation and toughness of nonwovens formed from the corresponding continuous fibre or staple.

The term "active amount of a degrading composition" is here defined as extending from 0% up to a concentration, by weight, sufficient to supplement the application of heat to a spun melt mix and the choice of polymer component and arrive at a spinnable _ 203557~

(resin) MFR value (preferably within a range of about 5 to 35).
Assuming the use of broad molecular weight polypropylene-containing spun melt, an "active amount" constitutes an amount which, at a melt temperature range of about 275C-320C and in the substantial absence of oxygen or oxygen-containing or -evolving gas, is capable of producing or obtaining a spun melt within the above-stated desirable MFR range.

The term "antioxidant/stabilizer composition", as here defined, comprises one or more art-recognized antioxidant compositions employed in effective amounts as below-defined, inclusive of phenylphosphites such as Irgafos~168, Ultranox~6261 Sandostab PEP-Q2; N,N'bis-piperidinyl diamine-containing compositions such as Chimassorb~119 or 9443;
hindered phenolics such as Cyanox~17903, Irganox~10761 or 1425 and the like.

The term "broad molecular weight distribution", is here defined as dry polymer pellet, flake or grain preferably having an MWD value (i.e., Wt.Av.Mol.Wt./No.Av.Mol.Wt.) of not less than about 5.5.

The term "quenching and finishing", as here used, is defined as a process step generic to one or more of the steps of gas quench, fibre draw (primary and secondary if desired) and texturing, (optionally inclusive of one or more of the routine steps of bulking, crimping, cutting and carding), as desired.

l Commercially obt~ri7;-hle as products of Ciba Geigy Corp 2Commercially obt~rinnble as a product of Sandos Chemical Co 3Commercially obt~ le as p,.du~ of American Cyanamid Co C

203~575 In one broad aspect, the present invention relates to a process for preparing a polypropylene-containing fibre or filament, comprising: extruding a hot extrudate comprising a polypropylene-containing material in an oxygen containing atmosphere; and maintaining conditions of the hot extrudate to effect oxygen diffusion into and oxidative chain scission degradation of the hot extrudate to produce a polypropylene-containing fibre or filament having a controlled surface zone comprising an external surface of the fibre or filament, an inner zone and a controlled gradient therebetween; the controlled surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to the inner zone, and the controlled gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

In another broad aspect, the present invention relates to a process for preparing a polypropylene-containing fibre or filament, comprising: extruding a hot extrudate comprising polypropylene having a broad molecular weight distribution into an oxygen-containing atmosphere; and processing the hot extrudate to produce a polypropylene-containing fibre or filament having a surface zone comprising an external surface of the fibre or filament, an inner zone and a gradient therebetween; the surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to the inner zone, and the gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

In yet another broad aspect, the present invention relates to a process for preparing at least one polypropylene-containing fibre or filament, comprising: extruding polypropylene-containing material having a broad molecular weight distribution to form at least one hot extrudate having a surface; and controlling quenching of the at least one hot extrudate in an oxygen-containing atmosphere so as to effect oxidative chain scission degradation of the surface to obtain at least one polypropylene-containing fibre or filament.

In a further broad aspect, the present invention relates to a process for preparing a fibre or filament from poly-propylene-containing spun melt composition, comprising (A) providing a melt comprising polypropylene polymer or copolymer and containing an effective amount of at least one antioxidant/
stabilizer wherein the polypropylene polymer or copolymer has a broad molecular weight distribution; (B) spinning the said melt at a temperature and atmospheric environment favouring minimal oxidative chain scission degradation of the polymeric component(s) within the melt during the spinning step; (C) taking up the resulting hot fibre or filament under an oxygen-rich atmosphere to obtain sufficient oxygen gas diffusion to effect threadline oxidative chain scission degradation of the filament; and (D) fully quenching and finishing the resulting fibre or filament to obtain a highly degraded surface zone of low molecular weight, and a minimally degraded inner zone.

In yet another broad aspect, the present invention relates to a fibre or filament obtainable by: extruding polypropylene having a broad molecular weight distribution to form at least one hot extrudate having a surface; and effecting oxidative chain scission degradation of the surface in an oxygen containing atmosphere so as to obtain a polypropylene-containing fibre or filament having a surface zone comprising an external surface of said fibre or filament, an inner zone and a gradient therebetween, the surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to said inner zone, and said gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

G

-In a further broad aspect, the present invention relates to a fibre or filament, consisting essentially of polypropylene and at least one antioxidant/stabilizer selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof, said fibre or filament having a surface zone comprising an external surface of said fibre or filament, an inner zone and a gradient therebetween; said surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to said inner zone, and said gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface; said surface zone and said gradient being formed by maintaining conditions of a hot extrude of polypropylene in an oxygen containing atmosphere to effect oxygen diffusion and oxidative chain scission degradation to obtain the fibre or filament.
.

In a further broad aspect, the present invention relates to a polyolefin fibre or filament containing an effective amount of at least one antioxidant/stabilizer composition, said fibre or filament comprising, in combination: (a) an inner zone identified by minimal oxidative polymeric degradation and a weight average molecular weight within a range of from 100,000 to 450,000; (b) an intermediate zone generally externally concentric to said inner zone and further identified by progressive oxidative chain scission degradation with a molecular weight gradation within a range of from slightly less than said inner zone to 10,000-20,000; and (c) a surface zone generally externally concentric to said intermediate zone and defining the external surface of the fibre or filament, said surface zone being identified by a high concentration of oxidative chain scission-degraded polymeric material, and a weight average molecular weight of less than 10,000.

In the attached drawings that illustrate the present invention by way of example:
Figure 1 is a cross-sectional schematic of a filament embodying the present invention in one aspect; and Figure 2 is a cross-sectional schematic of a filament embodying the present invention in another aspect.

The spun fibre obtained in accordance with the present invention can be continuous and/or staple fibre of a (1) monocomponent- or (2) bicomponent-type, the inner zone, in the former, having a relatively high crystallinity and birefringence with a negligible or very modest oxidative chain schssion degradation.

In the latter (2) bicomponent type, the corresponding inner layer of the sheath element is comparable to the centre cross sectional area of a monocomponent fibre, however, the bicomponent core element of a bicomponent fibre is not necessarily treated in accordance with the instant process or even consist of the same polymeric material as the sheath compoent, although generally compatible with or wettable by the inner zone of the sheath component.

The sheath and core elements of bicomponent fibre within the present invention can be conventional spun in accordance w~
C

equipment known to the bicomponent fibre art4 except for the preferred use of nitrogen or other inert gas environment to avoid or minimize oxygen diffusion into the hot spun melt or the hot core element prior to application of a sheath element around it.
In the latter (2) situation (see Figure 2 below), the sheath element should posses (a') an inner, essentially crystalline birefringent, non degraded zone contacting the bicomponent core, (b') an intermediate zone of indeterminate thickness and intermediate crystallinity and birefringence, and (c') a highly degraded bicomponent fibre surface zone, the three zones being comparable to the above-described three zones of a monocomponent fibre (see Figure 1 below).

As above noted, the instant invention does not necessarily require the addition of a conventional polymer degrading agent in the spun melt mix, although such use is not precluded by this invention in cases where a low spinning temperature and/or pressure is preferred, or if, for other reasons, the MFR value of the heated polymer melt is otherwise too high for efficient spinning. In general, however, a suitable MFR (melt flow rate) for initial spinning purposes is best obtained by careful choice of a broad molecular weight polyolefin-containing polymer to provide the needed rheological and morphological properties when operating within a spun melt temperature range of about 275 C-320C for polypropylene.

DESCRIPTION OF T~E DRAWINGS

Some of the features and advantages of the instant invention are further represented in Figures 1 and 2 as schematic cross sections of filament or fibre treated in accordance with the applicant's process.

4 See, for instance, U.S. Patents 3,807,917, 4,251,200, 4,717,325 and "Bicomponent Fibers" - R. Jeffries; Merrow Monograph Publishing Company, Pub.1971 C

203~

Figure l, as shown and above-noted represents a monocomponent-type filament or fibre and Figure 2 represents a bicomponent-type filament or fibre (neither shown to scale) in which ~'(C)Il of Figure 1 represents an approximate oxygen-diffused surface zone characterized by highly degraded polymer of less than about 10,000 (wt Av MW) and preferably falling within a range of about 5,000-lO,OOo and at least initially with a high smectic and/or beta crystal configuration; "(b)" represent an intermediate zone, preferably one having a polymer component varying from about 450,000 to about 10,000-20,000 (inside-to-outside), the thickness and steepness of the decomposition gradient depending substantially upon the extended maintenance of fibre heat, initial polymer MWD, the rate of oxidant gas diffusion, plus the relative amount of oxygen residually present in the dry spun mix which diffuses into the hot spun fibre upstream, during spinning and prior to the take up and quenching steps; inner zone "(a)", on the other hand, represents an approximate zone of relatively high birefringence and minimal oxidative chain scission due to a low or nonexistent oxygen concentration. As earlier noted, this zone usefully has a molecular weight within a range of about 100,000 to 450,000.

The above three zones within Figure 1, as previously noted are representative of a monocomponent fibre but such zones are usually not visually apparent in actual test samples, nor do they necessarily represent an even depth of oxygen diffusion throughout the treated fibre.

Figure 2 represents a bicomponent-type fibre also within the scope of the present invention, in which (a'), (b') and (c') are defined substantially as counterparts of a-c of Figure 1 while (d') represents a bicomponent core zone which, if desired, can be formed from a separate spun melt composition obtained and applied using a spin pack in a conventional manner4, provided inner layer (a') consists of a compatible (i.e., core-wettable) material. In addition, zone (d') is preferably formed and initially sheath-coated in a substantially non-oxidative 203~575 environment in order to minimize the formation of a low-birefringent low molecular weight interface between zones (d') and (a').

As before, the quenching step of the spun bicomponent fibre is preferably delayed at the threadline, conveniently by partially blocking the quench gas, and air, ozone, oxygen, or other conventional oxidizing environment (heated or ambient temperature) is provided downstream of the spinnerette, to assure sufficient oxygen diffusion into the sheath element and oxidative chain scission within at least surface zone (c') and preferably both (c') and (b') zones of the sheath element.

Yarns as well as webs for nonwoven material are conventionally formed from fibres or filaments obtained in accordance with the present invention by jet bulking, cutting to staple, crimping and laying down the fibre or filament in conventional ways and as demonstrated, for instance, in U.S.
Patents 2,985,995, 3,364,537, 3,693,341, 4,500,384, 4,511,615, 4,259,399, 4,480,000 and 4,592,943.

While Figures 1 and 2 show generally circular fibre cross sections, the present invention is not limited to such configuration, conventional diamond, delta, oval, "Y" shaped, and l'X" shaped cross sections and the like are equally applicable to the instant invention.

The present invention is further demonstrated, but not limited to the following examples:

EXAMPLE I
Dry melt spun compositions- identified hereafter as SC-1 through SC-12 are individually prepared by tumble mixing linear isotactic polypropylene flake identified as "A"-"D" in Table I~
and having Mw/Mn values of about 5.4 to 7.8 and a Mw range of 5 Obtained commercially from Himont Incorporated.

203~575 _g5,000-359,000, which are admixed respectively with about 0.1%
by weight of conventional stabilizersl The mix is then heated and spun as circular cross section fibre at a temperature of about 300 C under a nitrogen atmosphere, using a standard 782 hole spinnerette at a speed of 750-1200 M/m. The fibre thread lines in the quench box are exposed to a normal ambient air quench (cross blow) with up to about 5.4% of the upstream jets in the quench box blocked off to delay the quenching step. The resulting continuous filaments, having spin denier within a range of 2.0-2.6 dpf, are then drawn (1.0 to 2.5X), crimped (stuffer box steam), cut to 1.5 inches, and carded to obtain conventional fibre webs. Three ply webs of each staple are identically oriented and stacked (machine direction), and bonded, using a diamond design calender at respective temperatures of about 157 C
or 165 C, and 240 PLI (pounds/linear inch) to obtain test nonwovens weighing 17.4-22.8 gm/yd2. Test strips of each nonwoven (1" x 7") are then identically conventionally tested for CD strength6 elongation and toughness7. The fibre parameters and fabric strength are reported in Tables II-IV below using the polymers described in Ta~le I in which the l'AII polymers are used as controls.

EXAMPLE 2 (CONTROLS) Example 1 is repeated, utilizing polymer A and/or other polymers with a low Mw/Mn of 5.35 and/or full (non-delayed) quench. The corresponding webs and test nonwovens are otherwise identically prepared and identically tested as in Example 1.
Test results of the controls, identified as C-1 through C-9 are reported in Tables II-IV.

6 Using a tensile tester of Instron Incorporated.
7 Energy required to break fabric conventionally, based on stress/strain curve values.

TABLE I

Spun Mix Intrinsic Polymer SEC8 Visc. IV MFR
Identifi- Mw Mn (deci- (gm/
cation (g/mol) (g/mol) Mw/Mn leters/g) 10 min) A 229,000 42,900 5.35 1.85 13 B 359,000 46,500 7.75 2.6 5.5 C 2sO,000 44,000 6.59 2.3 8 D 300,000 42,000 7.14 2.3 8 8 Size Exclusion Chromatography~

C

TABLE II
Area %
Q u e n c h Box*
Melt Spin Blocked Sample Polymer MWD Temp C Off Comments C-l A 5.35 298 3.74 Control SC-l C 6.59 305 3.74 > 5.5 MWD
SC-2 D 7.14 309 3.74 > 5.5 MWD
SC-3 B 7.75 299 3.74 > 5.5 MWD
C-2 A 5.35 298 3.74 CTRL < 5.5 MWD
C-3 A 5.35 300 3.74 CTRL < 5.5 MWD
C-4 A 5.35 298 3.74 CTRL < 5.5 MWD
SC-4 D 7.14 309 3.74 No stabilizer SC-5 D 7.14 312 3.74 ---SC-6 D 7.14 314 3.74 ---SC-7 D 7.14 309 3.74 ---SC-8 C 6.59 305 5.38 SC-9 C 6.59 305 3.74 C-5 C 6.59 305 0 C T R L / F u 1 1 Quench C-6 A 5.35 290 5.38 CTRL < 5.5 MWD
C-7 A 5.35 290 3.74 CTRL c 5.5 MWD
C-8 A 5.35 290 0 CTRL < 5.5 MWD
SC-10 D 7.14 312 3.74 C-9 D 7.14 312 0 C T R L / F u 1 1 Quench SC-ll B 7.75 278 4.03 ---SC-12 B 7.75 299 3.74 ---SC-13 B 7.75 300 3.74 ---Note: CTRL = Control _ TABLE III

FIBRE
PROPER-TIES Tena- Elong-Melt MFR city ation Sample dg/min MWD dpf (g/den) % Comments C-1 25 4.2 2.50 1.90 343 Effect of MWD
SC-l 25 5.3 2.33 1.65 326 SC-2 26 5.2 2.19 1.63 341 SC-3 15 5.3 2.14 2.22 398 C-2 17 4.6 2.28 1.77 310 Additives C-3 14 4.6 2.25 1.74 317 Effect C-4 21 4.5 2.48 1.92 380 Low MWD
SC-4 35 5.4 2.28 1.59 407 High MWD
SC-5 22 5.1 2.33 1.64 377 Additives SC-6 14 5.6 2.10 1.89 357 Effect SC-7 17 5.6 2.48 1.54 415 SC-8 23~ 5.3 2.64 1.50 327 ~uench SC-9 25 5.3 2.33 1.65 326 Delay C-5 23 5.3 2.26 1.93 345 C-6 l9 4.5 2.28 1.81 360 Quench C-7 17 4.5 2.26 1.87 367 Delay C-8 18 4.5 2.28 1.75 345 SC-10 22 5.1 2.33 1.64 377 Quench C-9 15 5.2 2.18 1.82 430 Delay SC-11 11 5.4 2.40 2.00 356 ---SC-12 15 5.3 2.14 2.22 398 ---SC-13 24 5.1 2.59 1.65 418 ---r C

~_ 2035575 TABLE IY
FABRIC CHARACTERISTICS
lVariation in Calender Temperatures) Calender Fabric Melt- Temp Weight CDS CDE TEA
Sample ( C) (g/sq yd~ (g/in)(~ in.)(g/in,) C-l 157 22,8 153 51 42 SC-l 157 21.7 787 158 704 SC-2 157 19.2 513 156 439 SC-3 157 18.7 593 107 334 C-2 157 18.9 231 86 106 C-3 157 21.3 210 73 83 C-4 157 20.5 275 74 110 SC-4 157 18.3 226 83 102 SC-5 157 20.2 568 137 421 SC-6 157 19.1 429 107 245 SC-8 157 19.8 498 143 392 SC-9 157 21.7 787 158 704 C-5 157 19.4 467 136 350 C-6 157 19.1 399 106 233 C-7 157 19.8 299 92 144 C-8 157 17.4 231 83 105 SC-10 157 20.2 568 137 421 C-9 157 20.4 448 125 300 SC-11 157 19.4 274 86 122 SC-12 157 18.7 593 107 334 SC-13 157 19.4 688 132 502 1~ f~
'' V

20355 7~
TABLE IV (Continued) FABRIC C ~ACTERISTICS
(Variation in Calender Temperatures) Calender Fabric Melt Temp Weight CDS CDE TEA
Sample ( C) g/sq yd (g/in.) (~ in.) (g/in.) C-1 165 20.3 476 98 250 SC-1 165 22.8 853 147 710 SC-3 165 19.7 829 118 528 C-2 165 18.8 412 120 262 C-3 165 20.2 400 112 235 C-4 165 20.6 453 102 250 SC-4 165 19.3 400 110 239 SC-5 165 17.9 614 151 532 SC-6 165 19.9 718 142 552 SC-7 165 20.5 753 157 613 SC-8 165 20.4 568 149 468 SC-9 165 22.8 853 147 710 C-5 165 17.4 449 126 303 C-6 165 18.5 485 117 307 C-7 165 19.7 482 130 332 C-8 165 19.2 389 103 214 SC-10 165 17.9 614 151 532 C-9 165 19.4 552 154 485 SC-11 165 20.1 544 127 366 SC-12 165 lg.7 829 118 528 SC-13 165 19.2 746 138 576 1~

Claims

1. A process for preparing a polypropylene-containing fibre or filament, comprising:
extruding a hot extrudate comprising a polypropylene-containing material in an oxygen containing atmosphere; and maintaining conditions of the hot extrudate to effect oxygen diffusion into and oxidative chain scission degradation of the hot extrudate to produce a polypropylene-containing fibre or filament having a controlled surface zone comprising an external surface of the fibre or filament, an inner zone and a controlled gradient therebetween; the controlled surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to the inner zone, and the controlled gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

2. A process according to claim 1, wherein said polypropylene-containing material comprises a polypropylene having a broad molecular weight distribution.

3. A process for preparing a polypropylene-containing fibre or filament, comprising:
extruding a hot extrudate comprising polypropylene having a broad molecular weight distribution into an oxygen-containing atmosphere; and processing the hot extrudate to produce a polypropylene-containing fibre or filament having a surface zone comprising an external surface of the fibre or filament, an inner zone and a gradient therebetween; the surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to the inner zone, and the gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

4. A process for preparing a polypropylene-containing fibre or filament, according to claim 3, wherein the processing comprises effecting oxidative chain scission degradation of the surface of the extrudate in an oxygen containing atmosphere.

5. A process for preparing a polypropylene-containing fibre or filament, according to claim 3, wherein the processing comprises maintaining temperature conditions of the hot extrudate sufficiently high to effect gas diffusion into the hot extrudate to effect oxidative chain scission degradation of the hot extrudate.

6. A process for preparing a polypropylene-containing fibre or filament, according to claim 4, wherein the processing comprises maintaining temperature conditions of the hot extrudate sufficiently high to effect gas diffusion into the hot extrudate to effect oxidative chain scission degradation of the hot extrudate.

7. A process for preparing a polypropylene-containing fibre or filament, according to claim 3, wherein the processing comprises delaying quenching of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

8. A process for preparing a polypropylene-containing fibre or filament, according to claim 4, wherein the processing comprises delaying quenching of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

9. A process for preparing a polypropylene-containing fibre or filament, according to claim 5, wherein the processing comprises delaying quenching of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

10. A process for preparing a polypropylene-containing fibre or filament, according to claim 6, wherein the processing comprises delaying quenching of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

11. A process for preparing a polypropylene-containing fibre or filament, according to claim 3, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

12. A process for preparing a polypropylene-containing fibre or filament, according to claim 4, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

13. A process for preparing a polypropylene-containing fibre or filament, according to claim 5, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

14. A process for preparing a polypropylene-containing fibre or filament, according to claim 6, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

15. A process for preparing a polypropylene-containing fibre or filament, according to claim 7, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

16. A process for preparing a polypropylene-containing fibre or filament, according to claim 8, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

17. A process for preparing a polypropylene-containing fibre or filament, according to claim 9, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

18. A process for preparing a polypropylene-containing fibre or filament, according to claim 10, wherein the processing comprises delaying cooling of the hot extrudate to obtain oxygen diffusion and effect oxidative chain scission degradation of the hot extrudate.

19. A process for preparing a polypropylene-containing fibre or filament, according to any one of claims 3 to 18, wherein the processing comprises partially blocking flow of the oxygen-containing atmosphere to the hot extrudate to effect oxidative chain scission degradation of the hot extrudate.

20. A process for preparing at least one polypropylene-containing fibre or filament, comprising:
extruding polypropylene-containing material having a broad molecular weight distribution to form at least one hot extrudate having a surface; and controlling quenching of the at least one hot extrudate in an oxygen-containing atmosphere so as to effect oxidative chain scission degradation of the surface to obtain at least one polypropylene-containing fibre or filament.

21. A process according to claim 20, wherein the controlling quenching of the at least one hot extrudate in an oxygen containing atmosphere to effect oxidative chain scission degradation of the surface of the at least one fibre or filament includes controlling rate of quenching of the hot extrudate.

22. A process according to claim 21, wherein the controlling quenching comprises delaying quenching of the at least one hot extrudate.

23. A process according to claim 21, wherein the oxygen containing atmosphere comprises a cross-blow quench, and the controlling quenching comprises blocking an upper portion of the cross-blow quench.

24. A process according to claim 22, wherein the oxygen containing atmosphere comprises a cross-blow quench, and the controlling quenching comprises blocking an upper portion of the cross-blow quench.

25. A process according to claim 23, wherein the controlling quenching includes passing the at least one hot extrudate through a blocked zone.

26. A process according to claim 24, wherein the controlling quenching includes passing the at least one hot extrudate through a blocked zone.

27. A process according to claim 23, wherein the blocked zone is open to the oxygen containing atmosphere.

28. A process according to claim 24, wherein the blocked zone is open to the oxygen containing atmosphere.

29. A process according to claim 25, wherein the blocked zone is open to the oxygen containing atmosphere.

30. A process according to claim 26, wherein the blocked zone is open to the oxygen containing atmosphere.

31. A process according to claim 23, wherein up to about 5.4%
of the cross-blow is blocked.

32. A process according to claim 24, wherein up to about 5.4%
of the cross-blow is blocked.

33. A process according to claim 25, wherein up to about 5.4%
of the cross-blow is blocked.

34. A process according to claim 26, wherein up to about 5.4%
of the cross-blow is blocked.

35. A process according to claim 27, wherein up to about 5.4%
of the cross-blow is blocked.

36. A process according to claim 28, wherein up to about 5.4%
of the cross-blow is blocked.

37. A process according to claim 29, wherein up to about 5.4%
of the cross-blow is blocked.

38. A process according to claim 30, wherein up to about 5.4%
of the cross-blow is blocked.

39. A process according to any one of claims 20 to 38, wherein the controlling quenching includes immediately blocking an area as the at least one hot extrudate exits a spinnerette.

40. A process according to any one of claims 20 to 38, wherein the controlling quenching of the at least one hot extrudate in an oxygen containing atmosphere so as to effect oxidative chain scission of the surface comprises maintaining the temperature of the at least one hot extrudate above 250°C for a period of time to obtain oxidative chain scission degradation of the surface.

41. A process according to claim 39, wherein the controlling quenching of the at least one hot extrudate in an oxygen containing atmosphere so as to effect oxidative chain scission of the surface comprises maintaining the temperature of the at least one hot extrudate above 250°C for a period of time to obtain oxidative chain scission degradation of the surface.

42. A process for preparing a fibre or filament from polypropylene-containing spun melt composition, comprising A. providing a melt comprising polypropylene polymer or copolymer and containing an effective amount of at least one antioxidant/stabilizer wherein the polypropylene polymer or copolymer has a broad molecular weight distribution;
B. spinning the said melt at a temperature and atmospheric environment favouring minimal oxidative chain scission degradation of the polymeric component(s) within the melt during the spinning step;
C. taking up the resulting hot fibre or filament under an oxygen-rich atmosphere to obtain sufficient oxygen gas diffusion to effect threadline oxidative chain scission degradation of the filament; and D. fully quenching and finishing the resulting fibre or filament to obtain a highly degraded surface zone of low molecular weight, and a minimally degraded inner zone.

43. A process according to claim 42, wherein the said surface zone and said inner zone define an intermediate zone of intermediate polymeric oxidative degradation and crystallinity.

44. A process according to claim 42, wherein the oxygen-rich atmosphere in step C comprises air, ozone or oxygen.

45. A process according to claim 43, wherein the oxygen-rich atmosphere in step C comprises air, ozone or oxygen.

46. A process according to claim 42, wherein the take-up step is carried out in the presence of oxygen at ambient temperature.

47. A process according to claim 43, wherein the take-up step is carried out in the presence of oxygen at ambient temperature.

48. A process according to claim 44, wherein the take-up step is carried out in the presence of oxygen at ambient temperature.

49. A process according to claim 45, wherein the take-up step is carried out in the presence of oxygen at ambient temperature.

50. A process according to claim 42, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

51. A process according to claim 43, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

52. A process according to claim 44, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

53. A process according to claim 45, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

54. A process according to claim 46, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

55. A process according to claim 47, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

56. A process according to claim 48, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

57. A process according to claim 49, wherein the quenching step is carried out in the presence of an oxygen/nitrogen mixture in a ratio by volume from 100-10:0-90.

58. A process according to claim 50, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

59. A process according to claim 51, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

60. A process according to claim 52, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

61. A process according to claim 53, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

62. A process according to claim 54, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

63. A process according to claim 55, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

64. A process according to claim 56, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

65. A process according to claim 57, wherein the oxygen/nitrogen mixture has a temperature of from ambient temperature up to 200°C.

66. A process according to any one of claims 42 to 65, wherein quenching is delayed at the threadline, whereby the hot fibre or filament is taken up in the oxygen-rich atmosphere in step C in a substantially unquenched state.

67. A process according to any one of claims 42 to 65, wherein the quench gas is partially blocked and an oxidizing environment at heated or ambient temperature is provided further downstream to ensure oxidative chain scission of the surface zone.

68. A process according to claim 66, wherein the quench gas is partially blocked and an oxidizing environment at heated or ambient temperature is provided further downstream to ensure oxidative chain scission of the surface zone.

69. A process according to any one of claims 42 to 65, wherein the fibre or filament threadline is passed through a quench box in which it is exposed to a normal ambient air quench (cross blow) with up to 5.4% of the upstream jets in the quench box blocked off to delay the quenching step.

70. A process according to claim 66, wherein the fibre or filament threadline is passed through a quench box in which it is exposed to a normal ambient air quench (cross blow) with up to 5.4% of the upstream jets in the quench box blocked off to delay the quenching step.

71. A process according to claim 67, wherein the fibre or filament threadline is passed through a quench box in which it is exposed to a normal ambient air quench (cross blow) with up to 5.4% of the upstream jets in the quench box blocked off to delay the quenching step.

72. A process according to claim 68, wherein the fibre or filament threadline is passed through a quench box in which it is exposed to a normal ambient air quench (cross blow) with up to 5.4% of the upstream jets in the quench box blocked off to delay the quenching step.

73. A process according to any one of claims 42 to 65, wherein the melt is spun in step B at a temperature of from 250 to 325 ° C and wherein the temperature of the spun fibre or filament is brought to below 250° C in step D.

74. A process according to claim 66, wherein the melt is spun in step B at a temperature of from 250 to 325 ° C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

75. A process according to claim 67, wherein the melt is spun in step B at a temperature of from 250 to 325° C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

76. A process according to claim 68, wherein the melt is spun in step B at a temperature of from 250 to 325° C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

77. A process according to claim 69, wherein the melt is spun in step B at a temperature of from 250 to 325° C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

78. A process according to claim 70, wherein the melt is spun in step B at a temperature of from 250 to 325° C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

79. A process according to claim 71, wherein the melt is spun in step B at a temperature of from 250 to 325°C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

80. A process according to claim 72, wherein the melt is spun in step B at a temperature of from 250 to 325°C and wherein the temperature of the spun fibre or filament is brought to below 250°C in step D.

81. A process according to any one of claims 1 to 18, 20 to 38, 42 to 65, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

82. A process according to claim 19, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

83. A process according to claim 39 or 40, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

84. A process according to claim 41, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

85. A process according to claim 66, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

86. A process according to claim 67, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

87. A process according to claim 68, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

88. A process according to claim 69, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

89. A process according to claim 70, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

90. A process according to claim 71, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

91. A process according to claim 72, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

92. A process according to claim 73, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

93. A process according to claim 74, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

94. A process according to claim 75, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

95. A process according to claim 76, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

96. A process according to claim 77, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

97. A process according to claim 78, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

98. A process according to claim 79, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

99. A process according to claim 80, wherein the fibre or filament has an increasing melt flow rate toward the external surface.

100. A process for preparing at least one polypropylene-containing fibre or filament, according to claim 1, comprising controlling quenching of the hot extrudate in an oxygen containing atmosphere so as to obtain at least one fibre or filament having a decreasing weight average molecular weight towards the surface of the at least one fibre or filament, and an increasing melt flow rate towards the surface of the at least one fibre or filament.

101. A process for preparing at least one polypropylene-containing fibre or filament, according to claim 3, comprising controlling quenching of the hot extrudate in an oxygen containing atmosphere so as to obtain at least one fibre or filament having a decreasing weight average molecular weight towards the surface of the at least one fibre or filament, and an increasing melt flow rate towards the surface of the at least one fibre or filament.

102. A process for preparing at least one polypropylene-containing fibre or filament, according to claim 20, comprising controlling quenching of the hot extrudate in an oxygen containing atmosphere so as to obtain at least one fibre or filament having a decreasing weight average molecular weight towards the surface of the at least one fibre or filament, and an increasing melt flow rate towards the surface of the at least one fibre or filament.

103. A process for preparing at least one polypropylene-containing fibre or filament, according to claim 42, comprising controlling quenching of the hot extrudate in an oxygen containing atmosphere so as to obtain at least one fibre or filament having a decreasing weight average molecular weight towards the surface of the at least one fibre or filament, and an increasing melt flow rate towards the surface of the at least one fibre or filament.

104. A process according to claim 100, wherein the at least one fibre or filament comprises an inner zone including a weight average molecular weight of from 100,000 to 450,000 grams/mole.

105. A process according to claim 101, wherein the at least one fibre or filament comprises an inner zone including a weight average molecular weight of from 100,000 to 450,000 grams/mole.

106. A process according to claim 102, wherein the at least one fibre or filament comprises an inner zone including a weight average molecular weight of from 100,000 to 450,000 grams/mole.

107. A process according to claim 103, wherein the at least one fibre or filament comprises an inner zone including a weight average molecular weight of from 100,000 to 450,000 grams/mole.

108. A process according to claim 104, wherein the inner zone comprises a weight average molecular weight of from 100,000 to 250,000 grams/mole.

109. A process according to claim 105, wherein the inner zone comprises a weight average molecular weight of from 100,000 to 250,000 grams/mole.

110. A process according to claim 106, wherein the inner zone comprises a weight average molecular weight of from 100,000 to 250,000 grams/mole.

111. A process according to claim 107, wherein the inner zone comprises a weight average molecular weight of from 100,000 to 250,000 grams/mole.

112. A process according to claim 104, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

113. A process according to claim 105, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

114. A process according to claim 106, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

115. A process according to claim 107, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

116. A process according to claim 108, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

117. A process according to claim 109, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

118. A process according to claim 110, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

119. A process according to claim 111, wherein the inner zone comprises a melt flow rate of from 5 to 35 dg/min.

120. A process according to any one of claims 100 to 119, wherein the at least one fibre or filament comprises an outer zone including the surface of the at least one fibre or filament, and the outer zone comprises a weight average molecular weight of less than 10,000 grams/mole.

121. A process according to any one of claims 100 to 119, wherein the at least one fibre or filament comprises an outer zone including the surface of the at least one fibre or filament, and the outer zone comprises a weight average molecular weight of from 5,000 to 10,000 grams/mole.

122. A process according to claim 120, including an inter-mediate zone positioned between the inner zone and the outer zone having a weight average molecular weight and melt flow rate intermediate the inner zone and the outer zone.

123. A process according to claim 121, including an inter-mediate zone positioned between the inner zone and the outer zone having a weight average molecular weight and melt flow rate intermediate the inner zone and the outer zone.

124. A process according to claim 122, wherein the inner zone has a weight average molecular weight of 100,000 to 250,000, the intermediate zone has molecular weight gradation from less than the inner zone down to from 10,000 to 20,000, and the surface zone has a weight average molecular weight of 5,000 to 10,000.

125. A process according to claim 123, wherein the inner zone has a weight average molecular weight of 100,000 to 250,000, the intermediate zone has molecular weight gradation from less than the inner zone down to from 10,000 to 20,000, and the surface zone has a weight average molecular weight of 5,000 to 10,000.

126. A process according to claim 120, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

127. A process according to claim 121, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

128. A process according to claim 122, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

129. A process according to claim 123, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

130. A process according to claim 124, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

131. A process according to claim 125, wherein the inner zone has a high birefringence, and the outer zone has a low birefringence.

132. A process for preparing at least one fibre or filament, according to claim 1, comprising:
extruding a broad molecular weight distribution polyolefin containing material at a temperature and an environment under conditions minimizing oxidative chain scission degradation of polymeric components within the extruder.

133. A process for preparing at least one fibre or filament, according to claim 3, comprising:
extruding a broad molecular weight distribution polyolefin containing material at a temperature and an environment under conditions minimizing oxidative chain scission degradation of polymeric components within the extruder.

134. A process for preparing at least one fibre or filament, according to claim 20, comprising:
extruding a broad molecular weight distribution polyolefin containing material at a temperature and an environment under conditions minimizing oxidative chain scission degradation of polymeric components within the extruder.

135. A process for preparing at least one fibre or filament, according to claim 42, comprising:
extruding a broad molecular weight distribution polyolefin containing material at a temperature and an environment under conditions minimizing oxidative chain scission degradation of polymeric components within the extruder.

136. A process according to claim 132, wherein the resulting hot extrudate is immediately exposed to an oxygen containing atmosphere.

137. A process according to claim 133, wherein the resulting hot extrudate is immediately exposed to an oxygen containing atmosphere.

138. A process according to claim 134, wherein the resulting hot extrudate is immediately exposed to an oxygen containing atmosphere.

139. A process according to claim 135, wherein the resulting hot extrudate is immediately exposed to an oxygen containing atmosphere.

140. A process according to claim 132, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

141. A process according to claim 133, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

142. A process according to claim 134, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

143. A process according to claim 135, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

144. A process according to claim 136, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

145. A process according to claim 137, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

146. A process according to claim 138, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

147. A process according to claim 139, wherein the extruded fibre or filament has an inner zone that is substantially not degraded by oxygen.

148. A process according to claim 3, wherein said polypropylene having a broad molecular weight distribution comprises polypropylene having a molecular weight distribution of at least 5.5.

149. A process according to claim 20, wherein said polypropylene having a broad molecular weight distribution comprises polypropylene having a molecular weight distribution of at least 5.5.

150. A process according to claim 42, wherein said polypropylene having a broad molecular weight distribution comprises polypropylene having a molecular weight distribution of at least 5.5.

151. A process according to any one of claims 148, 149 or 150, wherein said polypropylene has a molecular weight distribution of at least 6.59.

152. A process according to any one of claims 148, 149 or 150, wherein said polypropylene has a molecular weight distribution of at least 7.14.

153. A process according to any one of claims 148, 149 or 150, wherein said polypropylene has a molecular weight distribution of at least 7.75.

154. A process according to claim 1, wherein the poly-propylene-containing material subjected to extrusion includes an antioxidant/stabilizer composition.

155. A process according to claim 3, wherein the poly-propylene-containing material subjected to extrusion includes an antioxidant/stabilizer composition.

156. A process according to claim 20, wherein the poly-propylene-containing material subjected to extrusion includes an antioxidant/stabilizer composition.

157. A process according to claim 42, wherein the poly-propylene-containing material subjected to extrusion includes an antioxidant/stabilizer composition.

158. A process according to claim 154, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an effective amount to control chain scission degradation of polymeric components in the extruder.

159. A process according to claim 155, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an effective amount to control chain scission degradation of polymeric components in the extruder.

160. A process according to claim 156, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an effective amount to control chain scission degradation of polymeric components in the extruder.

161. A process according to claim 157, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an effective amount to control chain scission degradation of polymeric components in the extruder.

162. A process for preparing a polypropylene-containing fibre or filament, according to claim 1, wherein the hot extrudate consists essentially of polypropylene and at least one antioxidant/stabilizer composition selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof.

163. A process for preparing a polypropylene-containing fibre or filament, according to claim 3, wherein the hot extrudate consists essentially of polypropylene and at least one antioxidant/stabilizer composition selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof.

164. A process for preparing a polypropylene-containing fibre or filament, according to claim 20, wherein the hot extrudate consists essentially of polypropylene and at least one antioxidant/stabilizer composition selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof.

165. A process for preparing a polypropylene-containing fibre or filament, according to claim 42, wherein the hot extrudate consists essentially of polypropylene and at least one antioxidant/stabilizer composition selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof.

166. A process according to claim 1, wherein the polypropylene-containing material subjected to extrusion includes, as an antioxidant/stabilizer, at least one of phenylphosphite and a N,N' bis-piperidinyl diamine derivative.

167. A process according to claim 3, wherein the polypropylene-containing material subjected to extrusion includes, as an antioxidant/stabilizer, at least one of phenylphosphite and a N,N' bis-piperidinyl diamine derivative.

168. A process according to claim 20, wherein the polypropylene-containing material subjected to extrusion includes, as an antioxidant/stabilizer, at least one of phenylphosphite and a N,N' bis-piperidinyl diamine derivative.

169. A process according to claim 42, wherein the polypropylene-containing material subjected to extrusion includes, as an antioxidant/stabilizer, at least one of phenylphosphite and a N,N' bis-piperidinyl diamine derivative.

170. A process according to claim 154, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

171. A process according to claim 155, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

172. A process according to claim 156, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

173. A process according to claim 157, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

174. A process according to claim 158, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

175. A process according to claim 159, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

176. A process according to claim 160, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

177. A process according to claim 161, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

178. A process according to claim 162, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

179. A process according to claim 163, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

180. A process according to claim 164, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

181. A process according to claim 165, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

182. A process according to claim 166 and 167, wherein said antioxidant/stabilizer is present in an amount of from 0.002 to 1% by weight.

183. A process according to claim 168, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

184. A process according to claim 169, wherein said anti-oxidant/stabilizer is present in an amount of from 0.002 to 1%
by weight.

185. A process according to any one of claims 170 to 184, wherein said antioxidant/stabilizer is present in an amount of from 0.005 to 0.5% by weight.

186. A process according to claim 1, wherein the polypropylene-containing material is extruded at a temperature of from 250°C to 325°C.

187. A process according to claim 3, wherein the polypropylene-containing material is extruded at a temperature of from 250°C to 325°C.

188. A process according to claim 20, wherein the polypropylene-containing material is extruded at a temperature of from 250°C to 325°C.

189. A process according to claim 42, wherein the polypropylene-containing material is extruded at a temperature of from 250°C to 325°C.

190. A process according to any one of claims 186 to 189, wherein the polypropylene-containing material is extruded at a temperature of from 275°C to 320°C.

191. A process according to any one of claims 42 to 65, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

192. A process according to claim 66, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

193. A process according to claim 67, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

194. A process according to claim 68, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

195. A process according to claim 69, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

196. A process according to claim 70, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

197. A process according to claim 71, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

198. A process according to claim 72, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

199. A process according to claim 73, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

200. A process according to claim 74, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

201. A process according to claim 75, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

202. A process according to claim 76, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

203. A process according to claim 77, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

204. A process according to claim 78, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

205. A process according to claim 79, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

206. A process according to claim 80, wherein the antioxidant/stabilizer is admixed into the melt in step A in the presence of a degrading agent.

207. A process according to any one of claims 1, 3, 20 or 42, wherein said fibre or filament comprises a percent elongation of 326 to 418.

208. A process according to any one of claims 1, 3, 20 or 42, wherein said fibre or filament is drawn 1.0 to 2.5 times.

209. A process according to any one of claims 1, 3, 20 or 42, wherein said fibre or filament has a tenacity of 1.54 to 2.22 g/den.

210. A process according to any one of claims 1, 3, 20 or 42, wherein the fibre or filament is a monocomponent fibre or filament.

211. A process according to claim 1, wherein the fibre or filament is a bicomponent fibre or filament.

212. A process according to claim 3, wherein the fibre or filament is a bicomponent fibre or filament.

213. A process according to claim 20, wherein the fibre or filament is a bicomponent fibre or filament.

214. A process according to claim 42, wherein the fibre or filament is a bicomponent fibre or filament.

215. A process according to any one of claims 211, 212, 213 or 214, wherein the fibre or filament is a sheath-core bicomponent fibre or filament and said sheath has an inner zone that is internally contiguous with and generally externally concentric to a core element.

216. A fibre or filament obtainable by:
extruding polypropylene having a broad molecular weight distribution to form at least one hot extrudate having a surface;
and effecting oxidative chain scission degradation of the surface in an oxygen containing atmosphere so as to obtain a polypropylene-containing fibre or filament having a surface zone comprising an external surface of said fibre or filament, an inner zone and a gradient therebetween, the surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to said inner zone, and said gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface.

217. A fibre or filament according to claim 216, wherein the polypropylene is extruded as part of a composition consisting essentially of the polypropylene and at least one antioxidant/stabilizer selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof.

218. A fibre or filament, consisting essentially of polypropylene and at least one antioxidant/stabilizer selected from the group consisting of phenylphosphites, N,N' bis-piperidinyl diamine-containing compositions, and hindered phenolics, and mixtures thereof, said fibre or filament having a surface zone comprising an external surface of said fibre or filament, an inner zone and a gradient therebetween;

said surface zone comprising a high concentration of oxidative chain scission degraded polymeric material as compared to said inner zone, and said gradient comprising a decreasing weight average molecular weight and an increasing melt flow rate towards the external surface;
said surface zone and said gradient being formed by maintaining conditions of a hot extrude of polypropylene in an oxygen containing atmosphere to effect oxygen diffusion and oxidative chain scission degradation to obtain the fibre or filament.

219. A polyolefin fibre or filament containing an effective amount of at least one antioxidant/stabilizer composition, said fibre or filament comprising, in combination:
(a) an inner zone identified by minimal oxidative polymeric degradation and a weight average molecular weight within a range of from 100,000 to 450,000;
(b) an intermediate zone generally externally concentric to said inner zone and further identified by progressive oxidative chain scission degradation with a molecular weight gradation within a range of from slightly less than said inner zone to 10,000-20,000; and (c) a surface zone generally externally concentric to said intermediate zone and defining the external surface of the fibre or filament, said surface zone being identified by a high concentration of oxidative chain scission-degraded polymeric material, and a weight average molecular weight of less than 10,000.

220. A fibre or filament according to claim 219, wherein the polymer component of said inner zone of the sheath element has a molecular weight of from 100,000 to 250,000, the degraded polymer component of said intermediate zone has a molecular weight of from 10,000-250,000 down to less than 20,000, and the degraded polymer component of said surface zone has a weight average molecular weight of from 5,000 to 10,000.

221. A fibre or filament according to claim 216, generated from a polyolefin polymer or copolymer having a broad molecular weight distribution.

222. A fibre or filament according to claim 217, generated from a polyolefin polymer or copolymer having a broad molecular weight distribution.

223. A fibre or filament according to claim 218, generated from a polyolefin polymer or copolymer having a broad molecular weight distribution.

224. A fibre or filament according to claim 219, generated from a polyolefin polymer or copolymer having a broad molecular weight distribution.

225. A fibre or filament according to claim 220, generated from a polyolefin polymer or copolymer having a broad molecular weight distribution.

226. A fibre or filament according to claim 221, generated from a polyolefin polymer or copolymer having a molecular weight distribution of at least 5.5.

227. A fibre or filament according to claim 222, generated from a polyolefin polymer or copolymer having a molecular weight distribution of at least 5.5.

228. A fibre or filament according to claim 223, generated from a polyolefin polymer or copolymer having a molecular weight distribution of at least 5.5.

229. A fibre or filament according to claim 224, generated from a polyolefin polymer or copolymer having a molecular weight distribution of at least 5.5.

230. A fibre or filament according to claim 225, generated from a polyolefin polymer or copolymer having a molecular weight distribution of at least 5.5.

231. A fibre or filament according to claim 218, generated from a polypropylene having a broad molecular weight distribution.

232. A fibre or filament according to claim 219, wherein the polyolefin is polypropylene having a broad molecular weight distribution.

233. A fibre or filament according to claim 220, wherein the polyolefin is polypropylene having a broad molecular weight distribution.

234. A fibre or filament according to claim 216, generated from a polypropylene having a molecular weight distribution of at least 5.5.

235. A fibre or filament according to claim 217, generated from a polypropylene having a molecular weight distribution of at least 5.5.

236. A fibre or filament according to claim 231, generated from a polypropylene having a molecular weight distribution of at least 5.5.

237. A fibre or filament according to claim 232, generated from a polypropylene having a molecular weight distribution of at least 5.5.

238. A fibre or filament according to claim 233, generated from a polypropylene having a molecular weight distribution of at least 5.5.

239. A fibre or filament according to claim 234, wherein the polypropylene has a molecular weight distribution of at least 6.59.

240. A fibre or filament according to claim 235, wherein the polypropylene has a molecular weight distribution of at least 6.59.

241. A fibre or filament according to claim 236, wherein the polypropylene has a molecular weight distribution of at least 6.59.

242. A fibre or filament according to claim 237, wherein the polypropylene has a molecular weight distribution of at least 6.59.

243. A fibre or filament according to claim 238, wherein the polypropylene has a molecular weight distribution of at least 6.59.

244. A fibre or filament according to claim 234, wherein the polypropylene has a molecular weight distribution of at least 7.14.

245. A fibre or filament according to claim 235, wherein the polypropylene has a molecular weight distribution of at least 7.14.

246. A fibre or filament according to claim 236, wherein the polypropylene has a molecular weight distribution of at least 7.14.

247. A fibre or filament according to claim 237, wherein the polypropylene has a molecular weight distribution of at least 7.14.

248. A fibre or filament according to claim 238, wherein the polypropylene has a molecular weight distribution of at least 7.14.

249. A fibre or filament according to claim 234, wherein the polypropylene has a molecular weight distribution of at least 7.75.

250. A fibre or filament according to claim 235, wherein the polypropylene has a molecular weight distribution of at least 7.75.

251. A fibre or filament according to claim 236, wherein the polypropylene has a molecular weight distribution of at least 7.75.

252. A fibre or filament according to claim 237, wherein the polypropylene has a molecular weight distribution of at least 7.75.

253. A fibre or filament according to claim 238, wherein the polypropylene has a molecular weight distribution of at least 7.75.

254. A fibre or filament according to any one of claims 216 to 253 wherein the fibre or filament is a monocomponent fibre or filament formed from a common spun melt.

255. A fibre or filament according to any one of claims 216 to 253, being a sheath-core bicomponent fibre or filament wherein said inner zone is internally contiguous with and generally externally concentric to a core element.

256. A fibre or filament according to any one of claims 216 to 253 that has been spun from a melt.

257. A fibre or filament according to claim 254 that has been spun from a melt.

258. A fibre or filament according to claim 255 that has been spun from a melt.

259. A fibre or filament according to any one of claims 217 to 253, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

260. A fibre or filament according to claim 254, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

261. A fibre or filament according to claim 255, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

262. A fibre or filament according to claim 256, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

263. A fibre or filament according to claim 257, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

264. A fibre or filament according to claim 258, wherein the inner zone has a high birefringence and the surface zone has a low birefringence.

265. A fibre or filament according to any one of claims 216 to 243, wherein the fibre or filament has an increasing melt flow rate towards the external surface.

266. A fibre or filament according to any one of claims 216 to 253, wherein the fibre or filament has a percent elongation of 326 to 418.

267. A fibre or filament according to claim 254, wherein the fibre or filament has a percent elongation of 326 to 418.

268. A fibre or filament according to claim 255, wherein the fibre or filament has a percent elongation of 326 to 418.

269. A fibre or filament according to claim 256, wherein the fibre or filament has a percent elongation of 326 to 418.

270. A fibre or filament according to claim 257, wherein the fibre or filament has a percent elongation of 326 to 418.

271. A fibre or filament according to claim 258, wherein the fibre or filament has a percent elongation of 326 to 418.

272. A fibre or filament according to claim 259, wherein the fibre or filament has a percent elongation of 326 to 418.

273. A fibre or filament according to claim 260, wherein the fibre or filament has a percent elongation of 326 to 418.

274. A fibre or filament according to claim 261, wherein the fibre or filament has a percent elongation of 326 to 418.

275. A fibre or filament according to claim 262, wherein the fibre or filament has a percent elongation of 326 to 418.

276. A fibre or filament according to claim 263, wherein the fibre or filament has a percent elongation of 326 to 418.

277. A fibre or filament according to claim 264, wherein the fibre or filament has a percent elongation of 326 to 418.

278. A fibre or filament according to claim 265, wherein the fibre or filament has a percent elongation of 326 to 418.

279. A fibre or filament according to any one of claims 216 to 253, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

280. A fibre or filament according to claim 254, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

281. A fibre or filament according to claim 255, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

282. A fibre or filament according to claim 256, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

283. A fibre or filament according to claim 257, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

284. A fibre or filament according to claim 258, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

285. A fibre or filament according to claim 259, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

286. A fibre or filament according to claim 260, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

287. A fibre or filament according to claim 261, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

288. A fibre or filament according to claim 262, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

289. A fibre or filament according to claim 263, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

290. A fibre or filament according to claim 264, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

291. A fibre or filament according to claim 265, wherein the fibre or filament has a tenacity of 1.54 to 2.22 g/den.

292. A non-woven fabric or material produced by bonding fibres and/or filaments produced by a process according to any one of claims 1, 3, 20 or 42 and/or fibres and/or filaments according to any one of claims 216 to 253.

293. A non-woven fabric or material according to claim 292, produced by thermally bonding the fibres and/or filaments.

294. A non-woven fabric or material according to claim 292 produced by carding and thermally bonding the fibres and/or filaments.

295. A non-woven fabric or material according to claim 292, wherein thermally bonding is at about 157 to 165°C.

296. A nonwoven fabric or material according to claim 292 having a basis weight of 17.9 to 22.8 gm/yd2.

297. A nonwoven fabric or material according to claim 293 having a basis weight of 17.9 to 22.8 gm/yd2.

298. A nonwoven fabric or material according to claim 294 having a basis weight of 17.9 to 22.8 gm/yd2.

299. A nonwoven fabric or material according to claim 295 having a basis weight of 17.9 to 22.8 gm/yd2.

300. A nonwoven fabric or material according to claim 296 having a basis weight of 17.9 to 22.8 gm/yd2.

301. A non-woven fabric or material according to claim 292, having a cross directional strength of at least 400 g/in.

302. A non-woven fabric or material according to claim 293, having a cross directional strength of at least 400 g/in.

303. A non-woven fabric or material according to claim 294, having a cross directional strength of at least 400 g/in.

304. A non-woven fabric or material according to claim 295, having a cross directional strength of at least 400 g/in.

305. A nonwoven fabric or material according to claim 296 having a cross directional strength of at least 400 g/in.

306. A non-woven fabric or material according to claim 297, having a cross directional strength of at least 400 g/in.

307. A non-woven fabric or material according to claim 298, having a cross directional strength of at least 400 g/in.

308. A non-woven fabric or material according to claim 299, having a cross directional strength of at least 400 g/in.

309. A non-woven fabric or material according to claim 300, having a cross directional strength of at least 400 g/in.

310. A non-woven fabric or material according to claim 292 having an elongation of at least 107%.

311. A non-woven fabric or material according to claim 293 having an elongation of at least 107%.

312. A non-woven fabric or material according to claim 294, having an elongation of at least 107%.

313. A non-woven fabric or material according to claim 295, having an elongation of at least 107%.

314. A non-woven fabric or material according to claim 296, having an elongation of at least 107%.

315. A non-woven fabric or material according to claim 297, having an elongation of at least 107%.

316. A non-woven fabric or material according to claim 298, having an elongation of at least 107%.

317. A non-woven fabric or material according to claim 299, having an elongation of at least 107%.

318. A non-woven fabric or material according to claim 300, having an elongation of at least 107%.

319. A non-woven fabric or material according to claim 301, having an elongation of at least 107%.

320. A non-woven fabric or material according to claim 302, having an elongation of at least 107%.

321. A non-woven fabric or material according to claim 303, having an elongation of at least 107%.

322. A non-woven fabric or material according to claim 304, having an elongation of at least 107%.

323. A non-woven fabric or material according to claim 305, having an elongation of at least 107%.

324. A non-woven fabric or material according to claim 306, having an elongation of at least 107%.

325. A non-woven fabric or material according to claim 307, having an elongation of at least 107%.

326. A non-woven fabric or material according to claim 308, having an elongation of at least 107%.

327. A non-woven fabric or material according to claim 309, having an elongation of at least 107%.

328. A non-woven fabric or material according to claim 292, having a toughness of at least 239 g/in.

329. A non-woven fabric or material according to any one of claims 293 to 327 having a toughness of at least 239 g/in.

330. A non-woven fabric or material according to claim 292, having for a weight of 17.9 to 22.8 gm/yd2 and a bonding temperature of about 157°C to 165°C, a cross directional strength of 400 to 787 g/in and a cross directional elongation of 107 to 158 percent.

331. A non-woven fabric or material according to any one of claims 293 to 327, having for a weight of 17.9 to 22.8 gm/yd2 and a bonding temperature of about 157°C to 165°C, a cross directional strength of 400 to 787 g/in and a cross directional elongation of 107 to 158 percent.

332. A process according to any one of claims 1, 3, 20 or 42, in which the resultant fibre is a staple fibre.

333. A fibre according to any one of claims 216 to 253, being a staple fibre.

334. A fibre according to claim 254, being a staple fibre.

335. A fibre according to claim 255, being a staple fibre.

336. A fibre according to claim 256, being a staple fibre.

337. A fibre according to claim 257, being a staple fibre.

338. A fibre according to claim 258, being a staple fibre.

339. A fibre according to claim 259, being a staple fibre.

340. A fibre according to any one of claims 260 to 264, being a staple fibre.

341. A fibre according to claim 265, being a staple fibre.

342. A fibre according to claim 266, being a staple fibre.

343. A fibre according to any one of claims 267 to 278, being a staple fibre.

344. A fibre according to claim 279, being a staple fibre.

345. A fibre according to any one of claims 280 to 291, being a staple fibre.

346. A process as claimed in claim 1, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.

347. A process as claimed in claim 3, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.

348. A process as claimed in claim 20, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.

349. A process as claimed in claim 42, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.

350. A process as claimed in claim 215, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.

351. A process as claimed in claim 332, wherein the polypropylene-containing material is extruded from an extruder and includes an antioxidant/stabilizer composition in an amount which prevents or substantially limits chain scission degradation of the hot polypropylene-containing material in the extruder.