US3837946A

US3837946A - Manufacture of pile fabrics

Info

Publication number: US3837946A
Authority: US
Inventors: R Gribbin
Original assignee: IWS Nominee Co Ltd; Clark Son and Morland Ltd
Current assignee: IWS Nominee Co Ltd; Clark Son and Morland Ltd
Priority date: 1969-01-22
Filing date: 1971-08-27
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24

Abstract

Semi-artificial pile fabrics, having a fibrous pile of high density and with the fibres orientated as in natural pelts, are produced by first bonding the tips of the pile fibres of a woolled, furred or haired animal pelt to a temporary backing, leaving the remainder of the pile unbonded, cutting the pile from the skin, and bonding the cut ends of the pile fibres to a permanent backing, whereafter the temporary backing is removed. The temporary backing is preferably attached to the tips of the fibres by a relatively weak bond, so that it can be removed from the finished pile fabric by simply stripping off. If the pile is cut at a location between the temporary backing and the hide of the pelt, two pile materials are simultaneously produced, one comprising the pile on the temporary backing ready for transfer to a permanent backing and the other comprising the residual pile on the original hide.

Description

States Patent 1 1 Sept. 24, 1974 MANUFACTURE OF PILE FABRICS [75] inventor: Ronald Gribbin, Wells, Somerset,

England 22 Filed: Aug. 27, 1971 21 Appl.No.:175,752

Related US. Application Data [63] Continuation of Ser. No. 793,050, Jan. 22, 1969,

2,786,791 3/1957 Vandeweghe 156/68 3,075,867 l/1963 Cochran 156/72 3,309,259 3/1967 Schwartz 156/72 3,509,004 4/1970 Becker 156/72 Primary Examiner George F. Lesmes Assistant Examiner--M. E. McCamish Attorney, Agent, or FirmStowell & Stowell [5 7] ABSTRACT Semi-artificial pile fabrics, having a fibrous pile of high density and with the fibres orientated as in natural pelts, are produced by first bonding the tips of the pile fibres of a woolled, furred or haired animal pelt to a temporary backing, leaving the remainder of the pile unbonded, cutting the pile from the skin, and bonding the cut ends of the pile fibres to a permanent backing, whereafter the temporary backing is removed. The temporary backing is preferably attached to the tips of the fibres by a relatively weak bond, so that it can be removed from the finished pile fabric by simply stripping off. If the pile is cut at a location between the temporary backing and the hide of the pelt, two pile materials are simultaneously produced, one comprising the pile on the temporary backing ready for transfer to a permanent backing and the other comprising the residual pile on the original hide.

11 Claims, 12 Drawing Figures AIENIwsEPww swears Fig. 3J

MANUFACTURE OF PILE FABRICS This application is a continuation of application Ser. No. 793,050, filed Jan. 22, 1969, now abandoned.

This invention relates to the production of secondary pile fabrics from pile-bearing pelts, that is to say, pelts derived from furred, woolled or haired animals.

Processes for the production of semi-artificial pile fabrics have been described in which a primary pelt has a backing sheet attached to the free ends of the pile, to form a composite material. The pile may then be split to yield a secondary pile fabric, incorporating the backing sheet and a portion of the pile, together with the pelt, now having a shorter pile length. In the secondary pile fabric produced by these processes, the tipward ends of the pile fibres are attached to the backing sheet, whereas in the natural skin the rootward ends of the fibres are so attached. It has been found that animal fibres such as wool, which are liable to felting, may have a greater tendency to felt when their rootward rather-than their tipward ends are free.

In prior art processes of this kind, before attachment of the pile to the backing sheet, the outer portion of the pile is preferably sheared to ensure that all the fibre ends lie in one plane, and thus become attached to the backing sheet.

The present invention provides a process whereby secondary pile fabrics can be produced in which the fibres are oriented in the same way as in the natural piled animal skin that is to say, with the tipward ends of the fibres remote from the backing.

In other previously described processes a coagulant or binder is applied to a natural fur to bind the pileto gether, whereafter the skin is cut away and replaced by an artificial backing, the coagulant being subsequently washed out. In an early process of this type the pile was embedded in ice, which was ultimately removed by melting. Processes of thiskind are difficult to apply in practice, especially on the large scale.

In accordance with the invention, these difficulties are avoided by the use of a temporary backing in or to which the free ends of the pile of the pelt are weakly or temporarily bonded, leaving the remainder of the pile unbonded, and which, after the pile has been transferred to a permanent backing, is simply cut or stripped from the free or tipward ends of the pile of the secondary fabric.

The temporary backing may comprise a previously formed sheet, for example of paper, which is bonded to the fibre ends, for example by means of an adhesive coating. A pressure-sensitive adhesive may be employed, although the use of such adhesives is generally confined to those cases where the pelt is dry, as with a tanned sheepskin. Preferred adhesives are watersoluble adhesives, which can be used with wet fleeces, for example pickled sheepskins. Gums and other watersoluble adhesives have the additional advantage that they give a bond of adequate strength which yet can readily be removed by pulling. Alternatively, the backing may be formed in situ by applying an adhesive composition or a hardenable or polymerisable composition to the free ends of the pile fibres and causing or allowing the layer of composition to harden or solidify into a sheet.

A temporary backing sheet may be stripped from the free or tipward ends of the pile of the secondary fabric at the end of the process, with rupture of the adhesive or other bond. One outstandingly convenient and practical form of the invention employs a previously formed sheet material which is bonded to the free ends of the pile by a bond which, at least at the time of removal of the temporary backing, is weaker than the bond between the pile and the permanent backing. Alternatively, and especially in the case of a temporary backing formed in situ, the sheet may be cut from the pile, for example by slitting the pile with a band knife in the vicinity of the free or tipward ends, immediately adjacent to the sheet.

It is desirable that the cost of the temporary backing should be as low as possible. For this reason, paper coated with a water-soluble adhesive, such as a gum, is at present preferred. Alternatively, a re-usable sheet material may be employed as temporary backing which, after stripping from the secondary pile fabric and, if necessary, re-coating with adhesive, is returned for application to fresh pelts.

As an intermediate product, the new process produces a piled material which is in effect a temporarily supported pile layer. This layer is in a particularly convenient form for storage prior to further processing.

The function of the temporary backing is to support the cut pile layer during its passage through part of the process, though the pile layer may also be conveniently stored when attached to the temporary backing, and in this form may be used for purposes other than the manufacture of secondary pile fabrics. For example, it may be adhesively applied directly to a permanent surface, such as a wall, for decorative purposes, or be used in the manufacture of wallpaper.

The invention accordingly also provides a temporarily supported pile layer comprising a layer of pile and having a temporary backing bonded to fibre ends of the pile layer by a weak adhesive bond such that the temporary backing can be readily stripped from the pile layer. The bond may be inherently weak, as in the case of a pressure-sensitive, non-drying or permanently tacky adhesive, or potentially weak, as with a soluble or thermoplastic adhesive, when it can be weakened by treatment with the appropriate solvent or heat, respectively.

The fact that the temporarily supported fleece can be conveniently stored permits flexibility in the subsequent processing operations, since it is not necessary to stock large quantities of finished secondary pile fabrics with backings of all types to satisfy likely market requirements. The permanent backings can be applied to individual order as required, and in this way the changing dictates of fashion may readily be followed.

Furthermore, the supply of raw sheepskins is seasonally variable, and tanning of the skin must be carried out soon after it is removed from the animal. The invention now enables the fleece portions to be removed from the skins and stored at peak supply periods, while the skins themselves are tanned and progressed through the usual stages of leather manufacture. ln certain cases, the fleece may need an initial scouring before removal from the skin.

Application of the invention to pickled rather than tanned skins has several important other advantages. They give a secondary pile which is denser and in a more useful shape than that from a tanned skin, because the pickled skin has not undergone the stretching involved in the tanning process. The pile of a pickled skin is not tainted by tanning chemicals, and the subsequent tanning of the residual woolled skin is more economical since a larger number of skins can be accommodated in a given vat or volume of liquor owing to the removal of a substantial part of the pile.

Since in many cases the shape of the desired product will not bear any relation to that of the sheepskin which forms the starting point of the process, the temporarily supported fleece may be cut to shapes more convenient for processing, or to the shape required in the finished product. Following cutting to shape of the temporarily supported fleeces, it is easy to recover the waste fleece portions from their temporary backing.

Following attachment of the fleece to its permanent backing, should any loose fibres exist in the pile, these may be pulled out with the temporary backing when this is removed. The amount of loose fibres remaining on the support sheet when this is removed conveniently forms a process control check on the efficiency of bonding of the pile to its permanent backing.

The permanent backing constitutes the backing or support for the pile in the secondary pile fabric. Any suitable material can be employed as a permanent backing, but the preferred materials are textile fabrics, polymeric sheets and films, and leather. One particular advantage of the invention is the possibility of producing secondary pile fabrics on a wide range of backings. Backings may be selected which enable the fabric to be dyed by hot dyeing processes which cannot be used with natural skins owing to the damage caused to the leather. Moreover, suitable backings enable the fabrics to be washed and in some cases even boiled.

Permanent backings may be bonded to the cut pile by adhesive, which may be applied to the backing, to the cut fibres or to both, for example by spraying. Where a heat-curable polymerisable composition is employed, for example an acrylic emulsion adhesive, it is preferred to spray the adhesive onto the fibre ends and the backing and to bring the sprayed surfaces together in a flat bed press.

Polymeric films may be formed in situ on the fibre ends, but may also be employed as pre-formed thermoplastic sheets, for example of polyolefins such as polyethylene. The sheet may be softened by heat or solvent and the cut ends of the temporarily supported pile urged into the softened sheet, for example in a flat bed press, where heat and pressure can be applied at the same time. It is found that the fibre ends can be caused to penetrate completely through the sheet, resulting in a secondary fabric which is porous and has many properties resembling those of natural woolled skins. A reinforcing fabric may be bonded to the thermoplastic sheet, either before, during or after the bonding of the pile. It is, however, preferred to bond such a fabric at the same time as the pile, and the whole operation can be carried out in a flat bed press. Polyethylene is an example of a thermoplastic which can be softened by heat, and polystyrene film is an example of a material conveniently softened by a solvent, for example toluene.

The invention is especially valuable in its application to woolled skins. In such cases, since the free surface of the pile is retained in the semi-artificial product, any desirable feature or lie or patterning of natural fibres, for example curling or grouping of fibres, is retained in the product, giving the latter a natural effect. In some cases, the fibres may be straightened and aligned by combing and ironing after carrying out the process of the invention, to improve handle and appearance.

A particular advantage of the invention is that the process can be carried out without the use of complex mechanical equipment, and can be conveniently carried out manually, if necessary, especially in the case of the preferred form mentioned above. Furthermore, there is usually no need to shear the pile prior to production of the piled fabric, or otherwise to prepare it, as for example by combing or ironing.

By way of example, a preferred embodiment of the invention will now be described, with reference to the accompanying drawings in which:

FIGS. 1A, 1B and 1C illustrate steps in the production of a temporarily supported pile layer from a piled sheepskin;

FIGS. 2D, 2C, 2F and 2G illustrate steps in the production of a secondary pile fabric from the temporarily supported layer of FIGS. 1A, 1B and 1C, and

FIGS. 3H, 3L 3.] 3K and 3L show alternative steps to those of FIGS. 2D, 2E, 2F, and 20.

As shown in FIGS. 1A, 1B and 1C, the process commences with a pelt of natural piled sheepskin 10, the pile ll of which normally lies in irregular patterns, and the fibres of the pile being of unequal length. At B there is brought into contact with the free surface of the pile a sheet of brown paper 12, having tacky and strongly pressure sensitive adhesive layer 13 formed by spraying a vinyl-acrylic copolymer emulsion, sprayed onto the shiny side of the paper. The sheet of paper 12 thus forms a temporary backing for the pile layer.

Alternatively, the temporary backing 12 may be stuck to the pile by means of a water-soluble adhesive, as described hereinafter.

The sheepskin with the paper 12 attached is now taken, at C, to a band knife slitting machine in which the knife 14 cuts the pile of the sheepskin at a predetermined distance from the skin 10, so that there are formed two products the original sheepskin having only a portion 15 of the pile remaining on it, and the remainder of the pile held together, as a temporarily supported pile layer 16, by the paper 12.

All the fibres of the pile need not be attached to the temporary backing, since loose fibres will normally be supported by adjoining fibres in the layer.

The foregoing procedure can be modified by using as the temporary backing a gummed paper which is moistened (or the aqueous adhesive composition freshly applied) just before application of the coated surface of the paper to the tips of the skin fibres. With such adhesives, contact must be maintained between the adhesive surface and the fibre tips until the adhesive dries. Drying at ambient temperature tends to pucker the paper and cause it to separate from the fibres in isolated areas. To avoid this the wetted and applied paper is preferably subjected to accelerated drying, for example in a heated flatbed press, but preferably by passing the skin 10 with the wetted gummed paper uppermost (the paper corresponding to 12 and the gum layer to 13 in FIGS. 1A through 1C) beneath a bank of heaters, for example infra-red heaters.

The temporarily supported pile layer 16 with its paper backing can now be passed on to further processing for the production of a secondary pile fabric, or it can be stored in its temporarily supported form prior to cutting into any desired shape.

Turning now to FIGS. 2D through 2G which illustrate further steps in the processing of the temporarily supported pile 16, the free pile surface of the pile is coated, at D, by spraying with an aqueous emulsion of an acrylic copolymer 17, and is brought into contact, at E, with a permanent backing 18, which in the present example is a piece of flannelette material somewhat larger in area than the pile layer, having one surface sprayed with the same emulsion as that used to coat the pile layer.

Following the bringing together of the pile and its permanent backing, the double backed fabric is placed, at F, within a single heated platen press 19, and subjected to a temperature of 120C and pressure of 0.25 p.s.i. for 2 minutes. Gelling of the emulsion into a film thereupon occurs, and the fibre ends are anchored into this film.

The temperature, pressure and time conditions under which the platen press is operated depend upon the nature and thickness of the backing layer, and vary typically in the range of 120 to 170C, 0.25 to l p.s.i., and V4 to 3 minutes.

Following a curing period, the brown paper 12 is removed by pulling it away from the fleece, at G. This is readily carried out since the brown paper is less firmly attached to the wool than is the permanent backing 18.

The semi-artificial sheepskin product so obtained can be cut to any desired shape, and has many uses, for example as linings for garments or shoes, or as trimmings for the manufacture of sheepskin type slippers.

In a modified process, the permanent backing 18 is formed purely by a cured polymeric film, either with or without the incorporation of fillers such as chalk. The process is illustrated in FIGS. 3H through 3L, where one surface of a silicone release paper 21 is coated, at H, with the polymeric emulsion which in this case itself forms the permanent backing 22 for the pile. The free fibre tips of the temporarily supported pile are also lightly sprayed with the emulsion.

The temporarily supported fleece 16 is then brought into contact, at I, with the coated release paper 21 and the assembly is treated in the platen press 19 (at J), following which the release paper 21 and the temporary backing 12 are both stripped from the fleece, leaving the polymeric film 22 as the permanent backing of the pile. s

In place of the silicone release paper, a woven glass fibre material coated with PTFE may be used, and this material has the advantage of being re-usable, on account of its greater strength.

Where the acrylic film is required to be of substantial thickness, the emulsion used to produce the film can be thickened prior to spraying on to the silicone release paper or other release sheet. This thickening permits a greater depth of emulsion to be built up on the release surface, by reducing the flow characteristics of the emulsion. Moreover, the thickening, by its effect on the surface tension characteristics of the emulsion, reduces droplet formation tendency and promotes film formation.

By using a release paper or other sheet material having an embossed surface, the pattern of embossing will be transferred to the exposed surface of the permanent backing, to produce a surface having visual appeal or non-slip properties.

' a double backing, for example a fabric backing bonded to the polymeric film backing in which the fibres are anchored, to strengthen the resulting fabric or to give it a more attractive appearance.

Although the examples described above relate to successive treatment of single sheepskins, the simultaneous treatment of a number of sheepskins or other pelts or pieces thereof is possible. For example, at FIG. EU, the platen press 19 may be large enough to hold a single sheet of coated release paper 21 on which are placed a number of temporarily supported fleeces 16. It will also be apparent that various steps in the process are applicable to conveyor line operation.

Where the permanent backing is formed by a cured polymeric film, the effect of pressing the fibre ends of the pile into the emulsion prior to setting is to cause the fibre ends to take up an inclined position within the film. In one example the fibre end portions take up an angle of about to the plane of the film, and in this way the fibre ends anchored in the film contribute to the strength of the film, while the angled setting of each fibre end increases its anchorage within the film. By selecting a suitable resin, the hardness of the resulting film can be predetermined.

I claim:

l. A process for the production of a secondary pile fabric having a fibrous pile of high density and with the fibers thereof oriented as in the natural pelts of a pilebearing pelt, which comprises the steps of first bonding the free ends only of the pile fibers in or to a temporary backing consisting of a flexible backing sheet leaving the major portion of the rootward ends of the fibers free; cutting the pile fibers at a predetermined distance from the temporary flexible backing sheet to form a secondary pile; bonding the cut ends of the secondary pile to a permanent backing; and removing the temporary flexible backing sheet from the resulting secondary pile fabric.

2. A process as claimed in claim 1 wherein the temporary backing sheet is bonded to the pile by a bond which is weaker than the bond between the pile and the permanent backing sheet, at least at the time of removal of the temporary backing sheet.

3. A process as claimed in claim 2 wherein the temporary backing sheet is removed from the secondary pile fabric by pulling the said temporary backing sheet away from the pile.

4. A process as claimed in claim 2 wherein theadhesive on the temporary backing sheet is a pressuresensitive adhesive.

5. A process as claimed in claim 4 wherein the pelt is a dry tanned woolled sheepskin.

6. A process as claimed in claim 1 wherein the pile is out between the temporary backing sheet and the hide of the pelt, forming the secondary pile and leaving a residual pile material based on the hide of the original pelt.

7. A process as claimed in claim 1 wherein a layer of water-soluble adhesive on the temporary backing sheet is'wetted, brought into contact with the free ends of the pile and dried.

8. A process as claimed in claim 7 wherein the pelt is a pickled woolled sheepskin.

9. A process as claimed in claim 1 wherein the permanent backing is a thermoplastic sheet and wherein the cut ends of the secondary pile are bonded thereto by the steps of: softening one surface of the thermoplastic sheet; bringing the cut ends into contact with the softened surface; and applying pressure in a direction generally at right angles to the plane of the fabric to bond the thermoplastic sheet securely to the pile.

10. A process as claimed in claim 9 wherein a reinforcing textile fabric is bonded to the thermoplastic sheet by pressing said fabric against said sheet during bonding of said pile.

11. A process for the production of a secondary pile fabric from a pile-bearing pelt, which comprises forming a supported secondary pile by bonding the tipward ends only of the pile of the pelt in or to a temporary backing sheet leaving the major portion of the rootward ends of the fibers free, the pile being cut at a predetermined distance from the hide of the pelt to form a secondary pile of the required length, bonding the cut ends of the supported secondary pile to a permanent backing, and removing the temporary backing sheet from the resulting secondary pile fabric.

Po-ww UNITED STATES PATENT OFFICE c RTmcATE OF co Patent 3'83? Dated eptember 24, 1974 Inventor(s) RONALD GRIBBIN It is certified that; error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[30] Foreign Application Priority Data January 24, 1968 Great Britain...3780/68 Signed arid sealed this 28th day of January 1975.

(SEAL) Attest:

MCCOY M. ,GIBSON JR, c. MARSHALL DANN Attesting Officer Commissioner of Patents

Claims

2. A process as claimed in claim 1 wherein the temporary backing sheet is bonded to the pile by a bond which is weaker than the bond between the pile and the permanent backing sheet, at least at the time of removal of the temporary backing sheet.
3. A process as claimed in claim 2 wherein the temporary backing sheet is removed from the secondary pile fabric by pulling the said temporary backing sheet away from the pile.
4. A process as claimed in claim 2 wherein the adhesive on the temporary backing sheet is a pressure-sensitive adhesive.
5. A process as claimed in claim 4 wherein the pelt is a dry tanned woolled sheepskin.
6. A process as claimed in claim 1 wherein the pile is cut between the temporary backing sheet and the hide of the pelt, forming the secondary pile and leaving a residual pile material based on the hide of the original pelt.
7. A process as claimed in claim 1 wherein a layer of water-soluble adhesive on the temporary backing sheet is wetted, brought into contact with the free ends of the pile and dried.
8. A process as claimed in claim 7 wherein the pelt is a pickled woolled sheepskin.
9. A process as claimed in claim 1 wherein the permanent backing is a thermoplastic sheet and wherein the cut ends of the secondary pile are bonded thereto by the steps of: softening one surface of the thermoplastic sheet; bringing the cut ends into contact with the softened surface; and applying pressure in a direction generally at right angles to the plane of the fabric to bond the thermoplastic sheet securely to the pile.
10. A process as claimed in claim 9 wherein a reinforcing textile fabric is bonded to the thermoplastic sheet by pressing said fabric against said sheet during bonding of said pile.
11. A process for the production of a secondary pile fabric from a pile-bearing pelt, which comprises forming a supported secondary pile by bonding the tipward ends only of the pile of the pelt in or to a temporary backing sheet leaving the major portion of the rootward ends of the fibers free, the pile being cut at a predetermined distance from the hide of the pelt to form a secondary pile of the required length, bonding the cut ends of the supported secondary pile to a permanent backing, and removing the temporary backing sheet from the resulting secondary pile fabric.