WO1983004038A1

WO1983004038A1 - Polyester composition

Info

Publication number: WO1983004038A1
Application number: PCT/US1983/000707
Authority: WO
Inventors: Jeffrey T. Books; Michael E. Kucsma; Jesse D. Jones; Robert B. Whitehead; Edwin D. Hornbaker
Original assignee: Ethyl Corporation
Priority date: 1982-05-13
Filing date: 1983-05-06
Publication date: 1983-11-24

Abstract

Improved injection moldability of polyethylene terephtalates is achieved by the addition of small amounts of (i) a thermoplastic polymer mold releasability improver selected from a vinyl aromatic compound, an alpha-olefin-acrylic acid copolymer and at least one monoepoxyalkane and (ii) a sodium or alkali metal salt of a long chain monocarboxylic acid cooperative with first two improvers and optionally with the last to achieve improved moldability and mold releasability even when the composition is injection molded at temperatures of at least as low as 93oC. A molded test article is disclosed which includes a plurality of runners (A) which terminate into various test pieces (B, C, D, E).

Description

POLYESTER COMPOSITION This invention relates to thermoplastic polyester compositions which are especially useful for injection mold ing operations conducted at relatively low mold temperature It has long been known that polyethylene tere- phthalate (PET) has superior physical properties, e.g., resistance to chemical attack, and desirable mechanical and electrical properties. Despite these superior physical properties, PET is not always the material of choice for injection molding usage because relatively high mold temper¬ atures, e.g., 120°-140°C. , must be utilized to insure good moldability. Any attempt to use a lower mold temperature, e.g., 100°C. or lower, results in the injected material being unmoldable as, for one thing, the molded article sticks in the mold and often can only be removed with great difficulty. To circumvent this processing disadvantage, the molder is forced to select more expensive materials such as polybutylene terephthalate (PBT) , inasmuch as this poly (alkylene terephthalate) is easily moldable even when using mold temperatures as low as 60°C. By being able to use a lower mold temperature for PBT, the time necessary for cool¬ ing the injection molded article to a temperature at which it can be removed from the mold is considerably shorter than the cooling time necessary before the PET article can be removed from an initially hotter mold. Since this shorter cool-down period of PBT results in a shorter process cycle time and a higher rate of article production, economic justification exists for its use despite its higher unit cost. A welcome contribution to the art would be a

PET composition which can be injection molded at relative-

ly low mold temperatures (e.g., 100°C. and below) to yield articles exhibiting good moldability characteristics, e.g., good mold releasability, and desirable physical properties.

This invention provides a thermoplastic injection moldable composition which comprises an intimate admixture

(a) a polyethylene terephthalate;

(b) a mold releasability improver selected from (i) a thermoplastic polymer of a vinyl aromatic compound, (ii) at least one mono- epoxyalkane having from 10 to 50 carbon atoms in the molecule, or (iii) an alpha- olefin-acrylic acid copolymer resin in which the alpha-olefin repeating unit is one or more acyclic hydrocarbon alpha-olefins containing at least two but no more than eight carbon atoms in the repeating unit; an

(c) an adjuvant cooperative with the mold releasability improver of (b) (i) which is a sodium salt of an aliphatic monocarboxylic acid containing at least about 16 carbon ato in the molecule or with the mold releasabili improver of (b) (iii) which is an alkali meta salt of a substantially saturated mono¬ carboxylic acid to improve the releasability from the injection mold, of articles injection molded from said composition at mold temperatures of at least as low as 93°C.

Because of the cooperation between the components (b) and (c) above, the compositions may be molded at rela- tively low mold temperatures (e.g., in the range of 50°C. to 100°C.) without excessive sticking being encountered.

It will be understood, of course, that if desired the compositions of this invention may be injection molded at even higher mold temperatures (e.g., 100 to 150°C). A further aspect of this invention is that the compositions may additionally contain reinforcing amounts of a reinforcing filler, e.g., glass fibers either alone or in combination with particulate mineral fillers. Other additives may also be used in the composition such as flame retardants, impact modifiers, and the like.

A distinct advantage of the compositions of this invention containing the monoepoxyalkane mold releasability improver is the highly desirable color characteristics which they possess. More particularly they exhibit a neutr to creme white color even without use of any colorizing agents. Thus the compositions can be used for molding part having attractive appearance and coloration even though a colorizing agent is not employed therein. When colored objects are desired, the color characteristics of the blend are also of advantage in that the quantity of colorants used will be significantly less as compared to blends havin a less neutral coloration. The polyethylene terephthalate used herein is preferably homopolymeric PET although crystallizable PET copolymers may also be used. Exemplary of useful PET co¬ polymers are those copolymers in which the copolymer contai at least 80 mol percent of repeating units derived from terephthalic acid and ethylene glycol with the remainder (20 mol percent or less) being derived from other well known acid and/or glycol components. Representative acid components are phthalic acid, isophthalic acid, naphthalene 1,4- or 2,6-dicarboxylic acid, diphenyl-4,4 *-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, adipic acid, sebacic acid as well as their halogenated (preferably brominated) counterparts. The glycol components may be diethylene glycol, neopentyl glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 1,3-propanediol, 1,4- butanediol, dibromoneopentyl glycol, the bis(2-hydroxyethyl) ether of tetrabromobisphenol A, tetrabromo-p-xylylene glycol and the like.

The polyethylene terephthalates used herein can be virgin PET or reclaimed PET. Also the PET used in the compositions of this invention is injection moldable and thus generally can have an intrinsic viscosity (I.V.) as low as 0.3 and preferably between about 0.4 and 1.2, more preferably between about 0.5 and 1.0, as measured at Z5"C. in a solvent consisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethane. For most injec¬ tion molding applications polyethylene terephalates in whic the I.V. is in the range of 0.4 to 0.9 are most preferred.

The vinyl aromatic polymers utilized in the compo sitions of this invention are characterized by containing at least about 55% and preferably at least about 70% by weight of units of the formula:

R - C-CH₂-

Ph wherein, R is a hydrogen or an alkyl group of one to four carbon atoms, and Ph is a substituted or unsubstituted phenyl group which, when substituted, may contain up to about four alkyl groups (preferably containing no more than about four carbon atoms each) , up to about four chlorine atoms, up to about two aryl substituents (prefer¬ ably containing no more than about ten carbon atoms each) , with the total number of such substituents preferably being four or less. Combinations of the foregoing substituents may, of course, be present on the phenyl group and each substituent may differ from the others even when selected from the same class (e.g., methyl and ethyl, phenyl and tolyl, etc.). The remainder of the polymer units, if any, are units derived from at least one of the following monomers: alpha-olefins of from two to eight carbon atoms, butadiene, vinyl naphthalenes, acrylonitrile, methacrylo- nitrile, maleic anhydride, malei ide, vinyl acetate, and like olefinic monomers copolymerizable with vinyl aromatic monomers such as styrene. The vinyl aromatic polymer may be a homopolymer, copolymer, block polymer or graft poly¬ mer, and is formed from such vinyl aromatic monomers as styrene, ring-substituted methyl- or polymethylstyrenes, ring-substituted ethyl- or polyethylstyrenes, ring- substituted propyl- or polypropylstyrenes, ring-substituted butyl- or polybutylstyrenes, ring-substituted mixed poly-

^ alkylstyrenes wherein the alkyl groups dxffer from eacn other, ring-substituted chloro- or polychlorostyrenes, rin substituted alkyl- or polyalkyl chloro- or polychloro¬ styrenes in which the alkyl grou (s) contain(s) from one t four carbon atoms, alpha-methyl-styrene, ring-substituted methyl- or polymethyl-alpha-methyl-styrenes, ring-substitu ethyl- or polyethyl-alpha-methyl-styrenes, propyl- or poly propyl-alpha-methyl-styrenes, butyl- or polybutyl-alpha- ethyl-styrenes, ring-substituted mixed polyalky1-alpha- methyl-styrenes wherein the alkyl groups differ from each other, ring-substituted chloro- or polychloro-alpha-methyl styrenes, ring-substituted alkyl- or polyalkyl chloro- or polychloro-alpha- ethyl-styrenes in which the alkyl group( contain(s) from one to four carbon atoms, and similar poly merizable styrenic monomers — i.e., styrenic compounds capable of being polymerized by means of peroxide or like catalysts into thermoplastic resins. Homopoly ers and copolymers of simple styrenic monomers (e.g., styrene, p_- ethylstyrene, 2,4-dimethylstyrene, alpha- ethy1styrene, £-chlorostyrene, etc.) are preferred from the standpoints of cost and availability.

Although vinyl aromatic polymers of intermediate molecular weight (800 to 5,000) are satisfactory, best results are obtained when the polymer has a molecular weigh above 5,000.

The vinyl aromatic polymers, whether homopolymers or copolymers, used in the practice of this invention may be unmodified (i.e., devoid of a rubbery component) or they may be a rubber-modified polymer formed by blending the polymer, and preferably by grafting, the styrenic monomer and the co onomer(s) , if used — with an elasto eric sub¬ stance such as polybutadiene,^'butadiene-styrene copolymers, isobutylene isoprene copolymers, ethylene-propylene copolymers, ethylene-propylene diene oncmer terpolymers (EPDM), a d the like. Of the rubber modified styrenic polymers, those based on use of poly- cis-butadiene or butadiene-styrene copolymers as the rubber component, especially the polymers formed by grafting

technigues, are most preferred.

For best results the rubber-modified polymers should contain no more than about 15% and preferably no more than about 12% by weight of the rubber based on the weight of the rubber-modified vinyl aromatic polymer.

Methods for the production of the vinyl aromatic polymers generally involve bulk or solution polymerization using free-radical initiation. Such methods are well known to those skilled in the art and are reported in the litera- ture. See for example Encyclopedia of Polymer Science and Technology, Volume 13, pages 156 to 206, Intersσience Publishers, 1970.

Of the vinyl aromatic polymers, use of crystal polystyrene (i.e., unmodified polystyrene) , rubber-modified polystyrene (often referred to as high-impact polystyrene) , and styrene-maleic anhydride copolymers (rubber-free) is particularly preferred.

The compositions ofthis invention preferably have an amount of the vinyl aromatic polymer of (b) within the range of from 0.5 to 12 parts per hundred parts of PET and an amount of the sodium salt of (c) within the range of from 0.05 to 5 parts per hundred parts of PET. Most pre¬ ferably, the amounts of these components used fall within the range of from 2 to 8 parts of vinyl aromatic polymer and from 0.1 to 3 parts of the sodium salt per hundred part of PET.-

Without the use of the sodium salts of one or more aliphatic monocarboxylic acids each containing at least 16 carbon atoms in the molecule in conjunction with any one of the above described vinyl aromatic polymers there is no observed significant enhancement of PET mold- ability. In view of the impotence of the vinyl aromatic polymer and sodium salt when used individually, it is surprising that their use in combination gives the very noticeable moldability enhancement characterizing this invention.

Synergistic effect is noted for example by the use of sodium salts of substantially saturated aliphatic monocarboxylic acids, such as sodium pal itate (sodium hexadecanoate) , sodium stearate, sodium behenate, sodium ontanate, sodium tetracosanoate and the like. While less preferable use may be made of the sodium salts of the cor¬ responding mildly unsaturated aliphatic mono carboxylic acids such as sodium oleate, sodium ricinoleate, sodium linoleate, sodium palmitoleate, sodium vaccenate, sodium erucate and the like. Of the foregoing salts, sodium stearate is most preferred.

A highly preferred combination for use in this invention is the combination of a polystyrene or a styrene copolymer such as a styrene-maleic anhydride copolymer either or both of which may be in crystal or rubber-modifie form and a sodium salt of a monocarboxylic acid having 16 or more carbon atoms in the molecule, most preferably a salt of an alkanoiσ acid, such as sodium eicosanate, sodium stearate, or the like. Sodium stearate can be purchased from several sources; for example, it is available as Sodium Stearate T-l produced by Witco Chemical Corporation, Organic Division, New York, New York 10017.

The onoepoxyalkanes utilized in the compositions of this invention have from 10 to 50 carbon atoms (prefer¬ ably from 10 to 30 carbon atoms) in the molecule and may be utilized individually or as mixtures.

A few illustrative examples of monoepoxyalkanes suitable for use in this invention are: 3,4-eρoxypentacosane; 9,10.-epoxytriacontane; 7,8-epoxytetracontane; 2,3-epoxy- 5,7,7-trimethyloctane, and the like. Examples of preferred 1,2-epoxyalkanes include but are not limited to, the following: 1,2-epoxydecane; 1,2-epoxyundecane; 1,2-epoxydodecane; 1,2-epoxytridecane; 1,2-epoxytetradecane; 1,2-epoxypentadecane; 1,2- epoxyhexadecane; 1,2-epoxyheptadecane; 1,2-epoxyoctadecane; 1,2-epoxynonadecane; 1,2-epoxyeicosane; 1,2-epoxyhen- eicosane; 1,2-epoxydocosane; 1,2-epoxytricosane; 1,2- epoxytetracosane; 1,2-epoxypentacosane; 1,2-epoxyhexacosane;

- ORE OMPI 1,2-epoxyheptacosane; 1,2-epoxyoctacosane; 1,2-^poxynonacosane; 1,2-epoxytriacontane; the branched chain iso ers of any of the foregoing; and the like. Some of the 1,2-epoxyalkanes are available commercially under the following product designations:

(a) Vikolox 10 (1,2-epoxydecane) ;

(b) Vikolox 12 (1,2-epoxydodecane) ;

(c) Vikolox 14 (1,2-epoxytetradecane) ;

(d) Vikolox 16 (1,2-epoxyhexadecane) ; (e) Vikolox 18 (1,2-epoxyoctadecane) ; and

(f) Vikolox 20 (1,2-epoxyeicosane) . Examples of mixtures include, but are not limited to, mixtures of 1,2-epoxyalkanes comprising 1,2-epoxyalkanes from the C., (i,2-epoxyundecane) to the C, . (1,2-epoxytetra- decane) range; from the C,_ς (1 ,2-epoxypentadecane) to the

C-g (1,2-epoxyoctadecane) range; from the C_2Q (1,2- epoxyeicosane) to the C₂₄ (1,2-epoxytetracosane) range; and from the C₂₄ (1,2-eρoxytetracosane) ^' to the C,_Q (1,2- epoxytriacontane) range. More specifically, examples of mixtures of 1,2- epoxyalkanes include, but are not limited to, the following:

(a) a mixture of 1,2-epoxyalkanes chosen from the C,, to the C,₄ range comprising 25% 1,2- epoxyundecane,- 23% 1,2-epoxydodecane, 25% 1,2—epoxytridecane and 27% 1 ,2-epoxytetra- decane, available commercially under the product designation Vikolox 11-14;

(b) a mixture of 1,2-epoχyalkanes chosen from the C,₅ to C,_g range comprising 28% 1,2- epoxypentadecane, 28% 1,2-epoxyhexadecane,

28% 1,2-epoxyheptadecane and 16% 1,2-epoxy- octadecane, available commercially under the product designation Vikolox 15-18;

(c) a mixture of 1,2-epoxyalkanes chosen from the C_2Q to Cm , range comprising 47% 1,2- epoxyeicosane, 44% 1,2-epoxydocosane and 9% 1,2-epox tetracosane, available commercially under the product designation Vikolox 20-24; and (d) a mixture of 1,2-epoxyalkanes chosen from the C₂₄ to C₃₀ range comprising 24% 1,2- epoxytetracosane, 45% 1,2-epoxyhexacosane,

22% 1,2-epoxyoctacosane and 9% 1,2- epoxytriacontane, available commercially under the product designation Vikolox 24-28. The 1,2-epoxyalkanes and the 1,2-epoxyalkane ble heretofore described under the various Vikolox product designations are available commercially from Viking Chemic Company, 838 Baker Building, Minneapolis, Minnesota 55402.

Although at least one or more monoepoxyalkanes having from 10 to 50 carbon atoms in the molecule may be utilized in the compositions of this invention, processing considerations and availability make it convenient to use one or more 1,2-epoxyalkanes within the range of 12 to 30 carbon atoms.

The compositions of this invention preferably have an amount of at least one monoepoxyalkane within the range of from 0.5 to 12 and most preferably from 2 to 8 parts per hundred parts of PET. Preferred compositions of this invention preferably have, in addition to at least one monoepoxyalkane, an amount of a synergistic adjuvant within the range of from 0.05 to 5 and most preferably from 0.1 to 3 parts per hundred parts of PET.

The compositions of this invention utilizing the combination of a synergistic adjuvant and at least one monoepoxyalkane exhibit a more significant enhancement of PET moldability.

Synergistic effect is exhibited by the use of alkali metal salts of aliphatic monocarboxylic acids, alkali metal salts of aromatic carboxylic acids, alkali metal salts of carbonic acid, ionomer resins having alkali metal cations, and the like. The sodium and potassium salts are preferred. Examples include, but are not limited to, the following: the sodium and potassium salts of

formiσ acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmit acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosanoic acid, behenic acid, tricosanoic acid, tetracosanoic acid, pentacosanoic acid, cerotic acid, montanic acid, methacrylic acid, acrylic acid and the like; lithium stearate and the like; the sodium and potassium salts of benzoic acid, toluic acid, p-tert-butylbenzoic acid, salicylic acid, vanillic acid, protocatechuic acid, veratric acid, gallic acid, phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid and the like; sodium carbonate, potassium carbonate and the like; and ionomer resins (sodium salt) with a melt flow index of

2.8 such as that available from E. I. du Pont de Nemours & Co. , Wilmington, Delaware, under the product designation Surlyn 1605, and the like. While less preferable, use may be made of the sodium or potassium salts of mildly un- saturated aliphatic monocarboxylic acids, such as the salts of oleic acid, ricinoleic acid, linoleic acid, palmitoleic acid, vaccenic acid, erucic acid and the like.

Preferred salts are sodium formate, sodium acetate, sodium stearate, potassium stearate, lithium stearate, sodium benzoate, sodium methacrylate , sodium carbonate and an ionomer resin (sodium salt) with a melt flow index of 2.8 such as that available from E. I. du Pont de Nemours & Company under the product designation Surlyn 1605. Preferred monoepoxyalkane-adjuvant combinations for use in this invention are the combinations of a 1,2- epoxyalkane or a mixture of 1,2-epoxyalkanes and ionomer resins (sodium salts) with a melt flow index of 2.8 such as that available frαti E. I. du Pont de Nemours & Co. under the product designation Surlyn 1605 or an alkali metal salt of an aliphatic monocarboxylic acid or an alkali metal salt of an aromatic carboxylic acid or an alkali metal salt of a carbonic acid. It is most preferred to use the potassium or sodium salts of these acids.

The alpha-olefin-acrylic acid copolymers resins used as component (b) of this invention can be a random or a graft copolymer. Of the alpha-olefin repeating units, those which are derived, at least in part, from the monomer ethylene are preferred. Illustrative of various monomers or combinations of monomers which may be used to make alpha olefin-acrylic acid copolymers are: propylene; 1-butene; ethylene and propylene; ethylene, propylene and 1,5- hexadiene; ethylene, propylene and ethylidene norbornene; ethylene and 1-butene; ethylene and 1-octene; and ethylene and 4-methyl-l-pentene.

The acrylic acid repeating unit, in the case where the alpha-olefin-acrylic acid copolymer is a graft copolymer, can either be the "backbone" portion of the copolymer or the "graft" portion of the copolymer. In either the random or graft types of the copolymer, the copolymerized acrylic acid can be present in an amount sufficient to give the copolymer an Acid Number within the range of from 25 to 140, measured as the milligrams KOH per gram of copolymer needed to titrate the copolymer to neutralization.

PET which contains neither the alpha-olefin- acrylic acid copolymer and the adjuvant, when injection molded undergoes severe sticking in the mold. It also has been demonstrated that the use of the adjuvant alone results in severe sticking. Surprisingly, the addition of the alpha-olefin-acrylic acid copolymers of this invention to the PET-adjuvant composition results in an enhancement of moldability characteristics, i.e., sticking is reduced.

As an adjuvant, sodium stearate is highly pre¬ ferred. In view of the coactive performance shown by sodium stearate with the alpha-olefin-acrylic acid co- polymers of this invention, it is contemplated that other alkali metal salts of substantially saturated aliphatic monocarboxylic acids will likewise perform. Exemplary of such monocarboxylic acid salts are sodium acetate, potassiu acetate, sodium propionate, potassium propionate, sodium hexoate, sodium octoate, sodium decanoate, sodium laurate, potassium laurate, sodium tetradecanoate, sodium hexa- decanoate and the like. Also commercially available soaps, such as IVORY soap (which is manufactured by the Procter and Gamble Company of Cincinnati, Ohio, and reported to contain sodium cocoanate and sodium salt of hydrogenated tallow oil), are deemed useful as adjuvants. A preferred class of adjuvants comprises the alkali metal salts of sub¬ stantially saturated aliphatic monocarboxylic acids having from 12 to 36 carbon atoms in the molecule and of these, the alkali metal salts of the acids containing from 16 to 30 carbon atoms in the molecule are especially preferred. Potassium myristate, sodium palmitate, sodium stearate, potassium stearate', sodium behenate and sodium montanate serve as examples of such materials. The potassium salts and especially the sodium salts of the above-described acids are most preferred, however, the lithium, cesium and rubidium salts, while not as available and economical, should perform satisfactorily with the alpha-olefin-acrylic acid copolymer to achieve the moldability enhancement sought.

These compositions preferably have an amount of the alpha-olefin-acrylic acid copolymer resin within the range of from 0.5 to 12 parts per hundred parts of PET and an amount of the adjuvant within the range of from 0.05 to 5 parts per hundred parts of PET. Most preferably, the amounts of these components used fall, per hundred parts of PET, within the range of from 2 to 8 parts of the alpha- olefin-acrylic acid copolymer resin and from 0.1 to 3 parts of the adjuvant.

As mentioned previously, other additives may also be utilized in the composition of this invention. For example, it is most useful if the composition additionally contains a reinforcing filler. This filler, depending on its nature, can increase the strength and impact qualities of the EET composition. In fact, the use of a reinforcing filler is often required by most present day commercial usage of injection molded PET. In general, any reinforce¬ ment can be used, e.g., fibers, whiskers, or platelets of metals, e.g., aluminum, iron or nickel, and the like, and non-metals, e.g., ceramics, carbon filaments, silicates, asbestos, titanate whiskers, quartz, glass- flakes and fibe and the like. Although it is only necessary to have at least a reinforcing amount of the reinforcing filler prese in general, the filler will comprise from 10 to 160 parts per hundred of the unreinforced polyethylene terephthalate resin. Amounts of filler, especially glass fibers, in the range of from 3^'0 to 140 parts per hundred of the unrein¬ forced PET are preferred as such compositions have parti- cularly desirable properties. From the standpoint of ease in injection molding usage, reinforced compositions of this invention, especially those using glass fibers, preferably contain a filler constituent in an amount within the range from 30 to 90 parts per hundred parts by weight of the un- reinforced polyethylene terephthalate resin.

Of the various fillers that may be used in the compositions of this invention, the preferred reinforcing fillers are glass. It is most preferred to use fibrous glass filaments of lime-aluminum borosilicate glass that are relatively soda free. This is known as "E" glass. The length of the glass filaments and whether they are bundled into fibers and the fibers bundled in turn to yarns, etc., is not critical to this invention. However, it has been found convenient to use glass strands of from about 1/8 inch long. It is to be understood that during compounding considerable fragmentation of the strands will occur and that even further reduction of length occurs in the final injection molded article.

Other additives may also be utilized in the composition of this invention to achieve certain desirable characteristics in the final injection molded product. For example, flame retardants may be added if the end use of the product requires the product to be possibly subjected to ignition sources. Flame-retarding additives which can be used for the compositions according to the invention comprise a large number of chemical compounds which are well known to. those skilled in the art. In general, they contain chemical elements which are used because of their flame-retarding capacity, for example, bromine, chlorine, antimony, phosphorus and nitrogen. Preferably, the flame- retarding additives are bromine and/or chlorine contain- ing organic compounds (optionally used together with auxiliary compounds, such as antimony trioxide, zinc borate, etc.) or elementary phosphorus or phosphorus compounds such as ammonium polyphosphate, various bromine and/or chlorine containing organic phosphate esters, hexaphenoxyphosphazene and the like. To improve impact resistance,- impact modi¬ fiers may be added to the composition of this invention. Exemplary of suitable impact modifiers are ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers (having some of the acid functions neutralized) , ethylene- ethacrylic acid copolymers (having some of the methacrylic acid functions neutralized) , ethylene-alkyl acrylate- methacryliσ acid terpolymer (also having some of the meth¬ acrylic acid fnctions neutralized), ABS ,.methyl methacrylate grafted polybutadiene,methyl methacrylate.grafted poly(alkyl acrylates) , methyl methacrylate-styrene grafted rubbers, oxidized polyethylene, styrene- butadiene-styrene (S-B-S) block copolymers, styrene- butadiene multiblock copolymers, styrene-butadiene radial block copolymers, hydrogenated S-B-S block copolymers, styrene-butadiene rubber, terpolymers of ethylene, vinyl acetate and glycidyl methacrylate, copolymers of ethylene and glycidyl methacrylate, block copolymers of butadiene, styrene, and caprolactone, acrylic rubbers, EPDM, ethylene- ethyl acrylate copolymers, ethylene-ethyl acrylate co¬ polymers, polyester-ether multiblock copolymers such as copolymers of butylene glycol, polytetramethylene ether glycol and terephthalic acid, aliphatic esters such as poly(ethylene adipate) , polycarbonate, and the like. A ounts of impact modifiers generally fall within the rang of from 5 to 25 parts per hundred parts of PET.

For protection against thermo-oxidative degrada¬ tion, the customary amounts of stabilizers, preferably frαn 0.001 to 0.5 parts per hundred based upon the weight of the^"-unstabil- ized cαnposition, can be added to the^'cόπpdsitions of this invention. Examples of suitable stabilizers are phenols and phenol derivatives, preferably sterically hindered phenols which contain alkyl substituents with up to 6 carbon atoms in the position(s) ortho to the phenolic hydroxyl grou (s); amines, preferably secondary arylamines and their deriva¬ tives; phosphates and phosphites, preferably the aryl derivatives thereof; and quinones. A few non-limiting examples include 4,4'-bis(2,6-di-tert-butyIphenol) ,

1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl- 4-hydroxybenzyl)benzene,

4,4'-methylenebis(2,6-di-tert-butyIphenol) , 4,4'-butylidenebis (6-tert-butyl-m-cresol) , 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid diethyl ester,

N,N*-bis ( -naphthyl)-p_-phenylenediamine, N,N'-bis (1-methylheptyl)-p-phenylenediamine, phenyl-beta-naphthylamine, 4,4'-bis(alpha,alpha-dimethylbenzy1)diphen 1- amine, hydroquinone, p-benzoquinone, p-tert-butyIpyrocatechol, chloranil, and naphthoquinone.

To the compositions of this invention there may be additionally added ultraviolet ray absorbents, lubricants antistatic agents, colorizing agents, antifungal agents, foaming agents, etc. depending upon the ultimate use of the molded product.

The compositions of this invention can be pre- pared by blending the various components in a blender, e.g., a tumble blender or a Henschel mixer, compounding the mixtur in an extruder, e.g., a twin-screw 28 mm Werner-Pfleiderer extruder, and thereafter chopping the extrudate into pellets The resultant product is suitable for use in injection mold ing operations. It is noteworthy that the compositions of this invention can be satisfactorily injection molded at mold temperatures less than 100°C. with an acceptably short cycle time and with the molded article exhibiting physical properties which are commercially attractive or which at least have commercial potential.

The present invention is further illustrated in the following examples, which are not to be construed as limiting. EXAMPLES 1-7

The various PET compositions of these Examples were prepared by mixing the components to form a premix, compounding the premix in a single screw extruder at temper¬ atures of about 500°F. to 540°F. (260°C. to 282°C), and molding the pellets into test bars on a reciprocating screw injection molding machine. The injection mold was suit¬ ably shaped and dimensioned for providing an article having the configuration shown in the Figure of the Drawing — whic is a top plan view of the article. The mold utilized was a. center gated mold having a non-moveable planar sprue side and a moveable cavity side. As can be seen in the Figure, the article formed by the mold has a plurality of runners, labeled "A", which terminate into various test pieces. Emanating from the center of the runner grid is a conven- tional tapered sprue. Two of the test pieces are rect¬ angular bars and are labeled with the letter "B". These "B" bars are about 6 inches (15.24 cm) long, 1/2 inch (1.27 cm) wide and 1/4 inch (0.635 cm) thick. The test piece labeled "C" in the Figure is a rectangular bar which is 2-1/2 inches (6.35 cm) long, 1/2 inch (1.27 cm) wide and 1/8 inch (0.3175 cm) thick. The two "dog bone" shaped test pieces are labeled "D" and are used for the testing of tensile properties. They measure about 6-1/2 inches (16.51 cm) long, 1/8 inch (0.3175 cm) thick and 3/4 inch (1.905 cm) in width at each of their ends and 1/2 inch (1.27 cm) in width at their middles. The test piece labeled "E" is 4 inches (10.16 cm) long, 2-3/4 inches (6.985 cm) wide and 1/8 inch (0.3175 cm) thick. The runners and sprue are approximately 3/8 inch (0.9525 cm) in cross-sectional width. This configuration for the test article was chosen for its complexity and for its yield of test specimens which are used in accordance with well recognized standard tests. The complexity of the article configuration was thought sufficient to give a good prediction of moldability performance of the compo¬ sition when used to form typical commercial articles. The polyethylene terephthalate, glass and other ingredients used in the various compositions of the Exampl were as follows:

— Polyethylene terephthalate (PET) ; from Goodyear Tire and Rubber Company; Vituf 5901 - crystallin PET having an intrinsic viscosity of 0.59 measured at 25°C. in solvent consisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethane

— Glass Fiber strands; from Owens Corning Fibergla designated Owens Corning Fiberglas 419 AA (3/16 inch (0.476 cm) chopped strands)

— Polystyrene (unmodified or crystal grade) ; from Rexene Company; Rexene 110S

— Rubber-modified polystyrene (high impact grade) ; from ARCO/Polymers; Dylene 989

— Styrene-maleic anhydride copolymer; from ARCO/Polymers; DKB-290, an unmodified copolymer containing 18 weight percent maleic anhydride

— Sodium stearate; from Witco Chemical Company; T-l or Heat Stable grade.

Table I reports the moldability characteristics of various compositions of this invention (Examples 1-3) and of compositions not utilizing the combination of a vinyl aromatic polymer and a sodium salt pursuant to this invention (Comparative Examples 4-7) . Moldability of the compositions was evaluated by determining "the number of sticks" (i.e., the number of times the molding cycle had to be stopped and a molded specimen physically removed from the mold) in relation to the "number of shots" (i.e., the number of injections) that were made with the given PET composition. In severe cases, removal of a stuck part required prying or chiseling; in less severe cases, re¬ moval was possible by hand.

In Examples 1-7, the mold temperature was kept at approximately 200°F.. (93°C). All parts shown in Table I are by weight-

Table I Molding Characteristics of Various PET Compositions at 930°C.

Comparative

Examples Exampli ≥s

1 2 3 4 5 6 7

Composition

Polyethylene Terephthalate, parts 100 100 100 100 100 100 100

Glass Fiber, phr** 43 ^' 43 43 43 43 43 43

Polystyrene, phr** 3 3

High-Impact Polystyrene, phr** 3 ""•"" 3

Styrene-Maleic anhydride copolymer, phr** 3 3

Sodium Stearate, phr** 0.5 0.5 0.5 0.5

Moldability

Number of Sticks/Number of Shots 0/10 0/30 0/10 10/10 5/10 * 7/7 5/1

* Estimated - actual number of shots not recorded but approximately 50% of the shots stuck in the mold.

** Parts per 100 parts by weight of polyethylene terephthalate.

As can be seen from Table I, tne aosence or either the vinyl aromatic polymer or the sodium salt re¬ sulted in a composition which oftentimes stuck in the mold and 5 shar the

no s

balan 10 ject

agai (93° illus

contr

15 test

evalu

The A

as fo

20

25

Table II - Physical Properties of Various PET Compositions

Comparative

Examples Examples

5 7

Composition

Polyethylene Terephthalate, parts 100 100 100 100

Glass Fiber, parts/100 parts PET 43 43 43 43

Polystyrene, parts/100 parts PET 3 3 —

High-Impact Polystyrene, parts/100 parts PET

Styrene-Maleic Anhydride Copolymer, parts/100 parts PET __ 3 — 3

Sodium Stearate, parts/100 parts PET 0.5 0.5 — — -—

Properties

Specific Gravity 1.573 1.570 1.572 1.569

Tensile Yield, psi 19,900 20,900 20,000 20,200

3 Tensile Elastic Modulus, 10 psi 1,380 1,450 1,310 1,340

Elongation at Yield, % 10 10 10 10

Flexural Strength, psi 32,900 31,300 34,400 33,400

3 Flexural Elastic Modulus, 10 psi 1,440 1,360 1,370 1,420

Izod Impact, 1/4" bar, ft-lb/in. 2.0 1.8 2.2 1.9

Izod Impact, 1/8" bar, ft-lb/in. 2.1 1.8 2.1 1.9

EXAMPLES 8-15 Using the same procedure as in Examples 1-7, a group of specimens was prepared by injection molding using mold temperatures of 93°C. The formulations utilized in Examples 8-15 were made from the following materials:

— Polyethylene terephthalate (PET) ; from Goodyear Tire and Rubber Company; Vituf 5901 - crystalline PET having an intrinsic viscosity of 0.59 measured at 25°C. in solvent consisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethane

— Glass Fiber strands; from Owens Corning Fiberglas, designated Owens Corning Fiberglas 419 AA (3/16 inch chopped strands) — Polystryene (unmodified or crystal grade) ; from Mobil Chemical Company; Mobil 110S

— Intermediate molecular weight polystyrene, _τ (unmodified or crystal grade) ; from Hercules Inc.; designated as Piccolastiσ D100 — Styrene-Acrylonitrile copolymer (containing about 25% acrylonitrile) ; from Aldrich Chemical Company

— Styrene-maleic anhydride copolymer; from ARCO/ Polymers; designated as Dylark 338S, a rubber- modified copolymer^"containing about 4 weight percent rubber and about 13.4 weight percent maleic anhydride, the balance being styrene

— Sodium stearate; from Witco Chemical Company; T-l or, Heat Stable grade. The formulations tested and the moldability of the formulations (determined as in Examples 1-7) are set forth in Table III. Table III

Molding Characteristics of Various PET Compositions at 93°C.

Examples Comparative Examples

10 11 TI TI 14 15

Composition

Polyethylene Terephthalate, parts 100 100 100 100 100 100 100 100

Glass Fiber, phr** 43 43 43 43 43 43 43 43

Polystyrene (110S) , phr** 3 3

Polystyrene (D100) , phr**

Styrene-Acrylonitrile copolymer, phr**

Styrene-Maleic Anhydride copolymer, phr** 3

Sodium Stearate, phr** 0.5 0.5 0.5 0.5

Moldability

Number of Sticks/Number of Shots 0/15 5/10 0/12 11/16 3/12 7/7 9/9 9/9

** Parts per 100 parts by weight of polyethylene terephthalate

trή

It will be noted from Table III (cf. Examples 8 and 9) that while usable, the polystyrene of intermediate molecular weight resulted in a higher incidence of sticking than did the conventional high molecular weight polystyrene. Examples 11, 15 and 4 indicate that while a rubber- modified styrene-maleic anhydride copolymer gave a synergistic result, the magnitude of the improvement was not as great as that shown by a crystal grade of styrene- maleic anhydride copolymer (cf. Examples 3, 4 and 7) . Table IV sets forth the physical properties of the test specimens prepared in Examples 8, 9 and 10.

Table IV - Physical Properties of Various PET Compositions

Examples

10

Composition

Polyethylene Terephthalate, parts 100 100 100

Glass Fiber, phr** 43 43 43

Polystyrene, (110S) , phr** 3

Polystyrene, (D100) , phr**

Styrene-Acrylonitrile Copolymer, phr** — —— 3

Sodium Stearate, phr** 0.5 0.5 0.5

Properties

Specific Gravity 1.585 1.576 1.574

Tensile Yield, psi 17,900 20,300 22,800

3 Tensile Elastic Modulus, 10 psi 1,580 1,380 1,360

Elongation at Yield, % 10 — —

Flexural Strength, psi 30,100 32,100 32,400

3 Flexural Elastic Modulus, 10 psi 1,340 1,410 1,360

Izod Impact, 1/4" bar, ft-lb/in. 1.8 1.7 1.8

Izod Impact, 1/8" bar, ft-lb/in. 2.0 1.8 2.0

Vicat Softening Point, °C. 245 — —

Heat Deflection Temperature @ 264 psi., °C. 240 232 239

Heat Deflection Temperature @ 66 psi., °C. 254 252 254

Rockwell Hardness, R Scale 122 123 122

* * Parts per 100 parts by weight of polyethylene terephthalate.

EXAMPLES 16-21 Additional blends and test specimens were prepare as in Examples 1-7 using the following ingredients:

— Polyethylene terephthalate (PET).; from Goodyear Tire and Rubber Company; Vituf 5901 -

-{•crystalline PET having an intrinsic viscosity of 0.59 measured at 25°C. in solvent consisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethane

— Glass Fiber strands; from Owens Corning Fiberglas, designated Owens Corning Fiberglas 419 AA (3/16 inch chopped strands)

— MBS copolymer; from Kanegafuchi Chemical Company, designated as KaneAce B56, (believed to be a graft copolymer comprising methyl methacrylate, butadiene and styrene)

— ABS copolymer; from Borg Warner, designated as Blendex 101, (believed to be a graft copolymer comprising acrylonitrile, butadiene and styrene)

— Styrene-methyl methacrylate copolymer; from Richardson Company, designated as N.A.S. 81 (believed to contain about 20 to 30 weight percent of methyl methacrylate)

— Sodium stearate; from Witco Chemical Company; T-l or. Heat Stable grade.

The formulations tested and their moldability as determined in Examples 1-7 are set forth, in Table V.

Table V Molding Characteristics of Various PET Compositions at 93"C.

Example Comparative Examples 16 17 18 T9 20 ^r

Composition

Polyethylene Terephthalate, parts 100 100 100 100 100 100

Glass Fiber, phr** 43 43 43 43 43 43

MBS, phr** 3 3

ABS, phr**

Styrene-methyl methacrylate, phr** 3

Sodium Stearate, phr** 0.5 0.5 0.5

Moldability

Number of Sticks/Number of Shots 8/12 11/11 10/10 5/5 8/8 7/7

** Parts per 100 parts by weight of polyethylene terephthalate.

It will be noted (cf. Examples 16, 17 and 4) that the MBS copolymer gave a synergistic improvement in mold releaseability, albeit not as extensive as that given by other compositions of this invention tested. On the other hand, neither the ABS nor the styrene-methyl methacrylate copolymer tested in Examples 18 and 20, respectively, gave any improvement in moldability. It thus can be seen that not all styrenic copolymers give the synergistic improve¬ ments characterizing this invention. Since, on the basis of present knowledge and experimental evidence, there is no rational basis for predicting in advance whether any given combination of the sodium salt of a monocarboxylic acid (16 or more carbon atoms in the molecule) with a styrenic copolymer will give a synergistic result, recourse should be had in each instance to the simple expedient of performing a test pursuant to the procedures set forth, in the above Examples.

EXAMPLES 22-34 Additional blends and test specimens were pre- pared as in Examples 1-7 using the following ingredients:

— Polyethylene terephthalate (PET) ; from Goodyear Tire and Rubber Company; Vituf 5901 - crystalline PET having an intrinsic viscosity of 0.59 measured at 25°C. in solvent con- sisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethane

— Glass fiber strands; Owens-Corning Fiberglas Corp., Owens-Corning Fiberglas 419 AA (3/16 inch chopped strands) — 1,2-epoxyalkanes; from Viking Chemical

Company, 838 Baker Building, Minneapolis, Minnesota 55402; Vikolox 10, 12, 14,16, 18, 20, 11-14, 15-18, 20-24 and 24-28

— Sodium stearate; from Witco Chemical Company; T-l or. Heat Stable grade. Table VI (Examples 22-25) and Table VII (Examples 26-34) report the moldability characteristics of various compositions of this invention. Example 25 (Table VI) and Example 34 (Table VII) are examples of com- positions that do not contain an adjuvant. Moldability of the compositions was evaluated in the same manner previously described.

In Examples 22-34, the mold temperature was kept at approximately 200°F. (93°C.) . All parts shown in Tables VI and VII are by weight.

Table VI Molding Characteristics of Various PET Compositions

EXAMPLES

22 23 24 25

Composition

Polyethylene Terephthalate, parts 100 100 100 100

Glass Fiber, phr* 43 43 43 43

Vikolox 10^a, phr* 3 «• 3

Vikolox 12 , phr* 3

Vikolox 14^c, phr* 3 —

Sodium Stearate, phr* 0.5 0.5 0.5

Moldability Number of Sticks/Number of Shots 1/12 0/21 0/20 6/13

* Parts per 100 parts PET a 1,2-Epoxydecane from Viking Chemical Co. b 1, 2-Epoxydodecane from Viking Chemical Co. c 1,2-Epoxytetradecane from Viking Chemical Co.

Table VII

Molding Characteristics of Various PET Compositions

EXAMPLES

26 27 28 29 30 31 32 33 34

Composition

Polyethylene Terep .halate, parts 100 100 100 100 100 100 100 100 100

Glass Fiber, phr* 43 43 43 43 43 43 43 43 43

Vikolox 24-28 , phr* 3 3 3 3 3 3 3 3 3

Sodium Acetate, phr* 0.5 - - - - - - — -

Sodium Benzoate, phr* 0.5

Surlyn 1605^b, phr* 0.5

Sodium Carbonate, phr* 0.5

Sodium Methacrylate, phr* 0.5

Lithium Stearate, phr* 0.5

Potassium Stearate, phr* 0.5

Sodium Formate, phr* 0.5

Moldability

Number of Sticks/ Number of Shots 0/14 0/15 4/16 0/14 0/13 6/18 0/17 0/11 6/15

* Parts per 100 parts PET a Viking Chemical Co. blend of 24% C₂₄, 45% C_2g, 22% C , and 9% C_3Q 1,2-epoxyalkanes b Ionomer resin (sodium salt) , melt flow index 2.8, from E. I. du Pont de Nemours & Co.

Mi

The data shown in Tables VIII and IX xllustrate the good balance of physical properties exhibited by articl injection molded from compositions of this invention, as determined by the same procedures as used in Table II.

Table VIII - Physical Properties of Various PET Compositions

Examples

22 23 24 25

Composition

Polyethylene Terephthalate, parts 100 100 100 100

Glass Fiber, phr* 43 43 43 43

Vikolox 10^a, phr* 3.0 - - 3

Vikolox 12^b, phr* - 3.0 - -

Vikolox 14^c, phr* - - 3.0 -

Sodium Stearate, phr* 0.5 0.5 0.5 —

Properties

Specxfxc Gravity 1.605 1.592 1.592 1.562

Tensile Yield, 10³ psi 19.2 19.3 19.6 20.7

Tensile Elastic Modulus, 10° psi 1.43 1.61 1.39 1.39

Flexural Strength, 10³ psi _g 29.1 29.4 28.7 32.6

Flexural Elastic Modulus, 10 psi 1.42 1.39 1.39 1.28

Izod Impact, 1/4" bar, ft-lb/in. 1.5 1.7 1.7 1.5

Izod Impact, 1/8" bar, ft-lb/in. 1.8 1.9 1.8 1.7

Heat Deflection Temperature @ 264 psi, °C 242 240 242 229

Heat Deflection Temperature @ 66 psi, °C. 253 252 251 250

Rockwell Hardness, R Scale 122 122 123 —

^"*^" Parts per 100 parts PET a 1,2-Epoxydecane from Viking Chemical Co. b 1, 2-Epoxydodecane from Viking Chemical Co. c 1,2-Epoκytetradecane from Viking Chemical Co.

Table IX - Physical Properties of Various PET Compositions

Examples

26

Composition 27 28 29 30 34

Polyethylene Terephthalate, parts 100 100 100 100 100 100

Glass Fiber, phr* 43 43 43 43 43 43

Vikolox 24-28-a, phr* 3 3 3 3 3 3

Sodium Acetate, phr* 0.5 — - - - -

Sodium benzoate, phr* 0.5

Surlyn 1605^b, phr* 0.5

Sodium Carbonate, phr* 0.5

Sodium Methacrylate, phr* 0.5

Properties

Specxfxc Gravity „ 1.576 1.577 1.554 1.572 1.580 1.546 Tensile Yield, 10 psi ₆ 18.5 17.4 17.7 17.5 17.4 19.1 Tensile Elastic Modulus, 10 psi 1.47 1.51 1.43 1.29 1.58 1.36 Flexural Strength, 10³ psi _g 29.7 28.8 27.3 28.6 26.9 30.621 Flexural Elastic Modulus, 10 psi 1.35 1.36 1.27 1.30 1.34 1.28 Izod Impact, 1/4" bar, ft-lb/in. 1.4 1.5 1.4 1.2 1.6 1.4 Izod Impact, 1/8" bar, ft-lb/in. 1.7 1.8 1.6 1.5 2.0 1.7 Heat Deflection Temperature @ 264 psi, °C. 236 234 235 234 237 231 Heat Deflection Temperature @ 66 psi, °C. 252 250 250 254 256 251

Parts per 100 parts PET

Viking Chemical Co. blend of 24% C₂₄, 45% C_2g, 22% C Ionomer resin (sodium salt), melt flow index 2.8, fr

Table X reports the oldabilxty characteristics of compositions not in accordance with this invention

(Comparative Examples 35 & 36) . Moldability is defined an was determined in the same manner as in Examples 1-7. Table X

Molding Characteristics of PET Compositions Not of Thxs Invention .

Comparative Examples

35 36 Composition

Polyethylene Terephthalate, parts 100 100

Glass Fiber, parts/100 parts PET 43 43 Sodium Stearate parts/100 parts PET . - 0.5

Moldability

Number of Sticks/

Number of Shots 10/10** 10/10**

** Estimate - the number of shots were not recorded; however, in each run the molded specimen had to be physically removed from the mold.

EXAMPLES 37-41

Additional blends and tes specimens were pre- pared as in Examples 1-7 using the following ingredients:

— Polyethylene terephthalate (PET) ; from Goodyear Tire and Rubber Company; Vituf 5901 - crystalline PET having an intrinsic viscosity of 0.59 measure at 25°C. in solvent consisting of 60 percent by weight phenol and 40 percent by weight of tetrachloroethan .

— Glass Fiber strands; Owens Corning Fiberglas, Owens Corning Fiberglas 419 AA (3/16 inch, chopped strands) . — Propylene-ethylene-acrylic acid copolymer; from Rexchold Chemxcal, Inc. , Ther oplastxcs and Elastomers Div. , Hackettstown, New Jersey, 07840 and designated as Polybond 1016.

— An alpha-olefin-acrylic acid copolymer; from Rexchold Chemical, Inc., Thermoplastics and

Elastomer Div., Hackettstown, New Jersey, 07840 and designated as Polybond XEA-7. - -

— Ethylene-aerylie acid copolymer; from Allied Chemical, Fiber and Plastics Company, Morr stown, New Jersey and designated A-C 540A.

— Sodium stearate; from Witco Chemical Corporation, 5 Organic Division, New York, New York 10017 and designated as T-l, heat stable grade.

Table XI reports the moldability characteristics of various compositions of this invention- (Examples 37-39J. This table also reports (Comparative Examples 40 & 41] on

10 the moldability of a PET composition not utilizing -the com¬ bination of this invention, i.e., the alpha-olefin-acrylic acid copolymer is missing from the composition. Moldabilit of the compositions was evaluated in the same manner pre¬ viously described. Table XII reports the physical pro-*

15 pertxes of molded articles made from the compositions σf- Examples 37-39.

In the Examples, the mold tempera-ture was kept at approximately 200°F. (93°C.). All parts shown in the Tables are by weight.

Table XI

Polyethylene Terephthalate Compositions and Their Moldability at 93°C,

Example No. Cαtτparative Examples

37 38 tw To 41

PET Resin - parts 100 100 100 100 100

Glass Fibers - parts/100 parts PET 43 43 43 43 43

A-C 540A (ethylene-acrylic acid copolymer) - parts/100 parts PET 3.0

Polybond 1016 (propylene-ethylene acrylic acid copolymer) - parts/100 parts PET 3.0

Polybond XEA-7 - parts/100 parts PET 3.0

Sodium Stearate - parts/100 parts PET 0.5 0.5 0,5 0.5

No. of sticks/No. of shots 10/27 4/12 10/10 10/10

* Stuck in the mold frequently but could be easily removed therefrom by hand. In a subsequent repeat test with the same formulation in the same proportions, the number of sticks per number of shots was 2/20.

Table XII Compositions of this Invention and Their Physical Properties

Example No,

37 38 39

Composition

PET Resxn, parts 100 100 100 Fiberglass, parts/100 parts PET 43 43 43 AC540A, parts/100 parts PET 3 Polybond 1016, parts/100 parts PET 3 Polybond XEA-7/ parts/100 parts PET 3 Sodium Stearate, parts/100 parts PET 0,5 0.5 0.5

Properties

Specxfxc Gravity 1.568 1.560 1.558 Tensile Yield, psi ₃ 18,500 20,800 18,600 Tensile Elastic Modulus, 10 pel 1,570 1,380 1,390 Elongation at Yield, % 10 10 10 Flexural Strength, psi ₃ 29,700 30,500 27,400 Flexural Elastic Modulus, 10 psi 1,300 1,310 1,270 Izod Impact - 1/4 in. bar, ft-lb/in 2.1 2.0 1.7 Izod Impact - 1/8 in. bar, ft-lb/in 2.4 2.1 1,9 Vicat Softening Point, °C. 254 249 247 Heat Deflection Temp. , °C. @ 264 psi 240 241 243 Heat Deflection Temp., °C. @ 66 psi 255 254 254 Rockwell Hardness R Scale 120 120 119

The data shown in Table XII illustrate the good balance of physical properties exhibited by articles in¬ jection molded from compositions of this invention, as determined by the same procedures as used in Table II.

Claims

C L I M S

1. A thermoplastic composition which is injection- moldable at a relatively low mold temperature comprising an intimate admixture of:

(a) a polyethylene terephthalate;

(b) a mold releasability improver selected from

(i) a thermoplastic polymer of a vinyl aromatic compound, (ii) at least one monoepoxyalkane having from 10 to 50 carbon atoms in the molecule, or (iii) an alpha-olefin-acrylic acid copolymer resin in which the alpha-olefin repeating unit is one or more acyclic hydrocarbon alpha-olefin containing at least two but no more than eig carbon atoms in the repeating unit; and Cc) an adjuvant cooperative with the mold releasabili improver of (d) (i) which is a sodium salt of an aliphatic monocarboxylic acid containing at least about 16 carbon atoms in the molecule or with the mold releaseability improver of (d) (iii) which is an alkali metal salt of a substantially saturated aliphatic monocarboxylic acid to improve the releasability from the injection mold of articles injection molded from said composition at mold temperatures of at least as low as 93°C.

2. The composition of claim 1, wherein said improver of (b) is polystyrene.

3. The composition of claim 2, wherein said polystyr is a crystal polystyrene.

4. The composition of claim 3, wherein said polystyr has a molecular weight above about 5,000.

5. The composition of claim 2, wherein said polystyr is a rubber modified polystyrene.

6. The composition of claim 1, wherein said improver of Cbl is a styrene-maleic anhydride copolymer.

7. The composition of claim 6, wherein said styrene- maleic anhydride copolymer is a rubber-free copolymer.

8. The composition of claim 1, wherein said improve of (b) is a εtyrene-acrylonitrile copolymer.

9. The composition of claim 1, wherein said improve of (b) is a copolymer comprising methyl methacrylate, butadiene and styrene.

10. The composition of claim 2, wherein said salt is sodium stearate.

11. The composition of claim 1, wherein said improve of (b) is an alpha-olefin-acrylic acid copolymer resin in which the alpha-olefin repeating unit is one or more acrylx hydrocarbon alpha-olefins containing at least two but no mor than eight carbon atoms in the repeating unit.

12.. The composition of claim 11, wherein said alpha- olefin-acrylic acid copolymer is a random copolymer.

13. The composition of claim 11, wherein said alpha- olefin-acrylic acid copolymer is a graft copolymer.

14. The composition of claim 11, wherein said alpha- olefin-acrylic acid copolymer is ethylene-acrylic acid copolymer.

15. The composition of claim 11, wherein said alpha- olefin-acrylic acid copolymer is an acrylic acid grafted ethylene-propylene copolymer.

16. The composition of claim 1, wherein said improver of (b) is at least one monoepoxyalkane having from 10 to 50 carbon atoms.

17. The composition of claim 16, wherein said monoepo alkane contains from 10 to 30 carbon atoms in the molecule.

18. The composition of claim 16, wherein said monoepo alkane is a 1,2-epoxyalkane.

19. The composition of claim 18, wherein said 1,2- epoxyalkane is 1,2-epoxydecane, 1,2-epoxydodecane, 1,2- epoxytetradecane, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane or 1,2-eρoxyeicosane.

20. The composition of claim 18, wherein said 1,2- epoxyalkane is a mixture of at least two 1,2-epoxyalkanes.

21. The composition of claim 16, wherein said com¬ position additionally comprises an adjuvant synergistically cooperative with the monoepoxyalkane of (b) which, is an alkali metal salt of an aliphatic monocarboxylic acid or of an aromatic ca boxylic acid or of carbonic acid.

22. The composition of claim 21, wherein said salt is a sodium or potassium salt.

23. The composition of claim 1, wherein said com¬ position additionally contains a reinforcing filler.

24. The composition of claim 23, wherein said reinforcing filler is glass fibers.

25. The composition of claim 1, wherein said polyethylene terephthalate is a polyethylene terephthalate having an intrinsic viscosity in the range of 0.4 to 0.9 as measured at 25°C. in a solvent consisting of 60% by weight of phenol and 40% by weight of tetrachloroet ane.