STABILIZED THERMOPLASTIC ELASTOMER COMPOSITIONS

Abstract: Segmented thermoplastic copolyester elastomers con­ tain recurring polymeric long chain ester units derived from phthalic acids and long chain glycols and short chain ester units derived from phthalic acids and 1,4-butanediol or 1,4-butenediol. The elastomers also contain polyvinylpyrroli­ dine and preferably also contain small amounts of guani­ dine stabilizer, phosphorus stabilizer and diphenylamine.

Description: STABILIZED THERMOPLASTIC ELASTOMER COMPOSITIONS Backcround of the Tnvention Thermoplastic copolyester elastomers in which the polyester is modified with long rubbery segments have long been known in the art and are used in the preparation of molded and extruded articles. Such resins can be used alone or in conjunction with fillers or other resins to provide materials having a variety cf properties. It is well known, however, that materials of this general type are subject to thermal degradation. S. S. patents 3.023,'92, 3,651,014, 3,766,146, 3,784,520 and 3,763,109 are among prior patents describing elastomers of this type. Unstabilized elastomers of the type described above exhibit poor processing behavior and unacceptable performance, especially at elevated temperatures. While a number of antioxiant stabilizers are availat for use in polymers, many are unsuitable for use in copolyester elastomers of the type mentioned above because of the severe time-temperature conditions involved in the manufacture and/or use of such elastomer When used in elastomers of this type, most available stabilizers either inhibit polymer formation or result in production of a non-white colored product. Addition- ally most available stabilizers do not trovice adequate long term retention of desirable mechanical and thermal properties. U. S. patents 4,355,155 and 4,405,749 escribe elastomer of the general type described above but which is modified to provide improved thermal stability together with a desirable white color. Summary of the Invention It is an object of the present invention to provide thermoplastic copolyester elastomers of the general type described above, but with improved thermal stability, particularly at elevated use temperatures. In accordance with the invention, a thermoplastic elastomer composition is provided which consists essentially of: : a) segmented thermoplastic copolyester elastomer consisting essentially of a multiplicity of recurring long chain ester units and short chain ester units joined head to tail through ester linkages, said long chain units being represented by the formula EMI2.1 Formula I and said short chain units being represented by the formula EMI2.2 Formula TI where G is a divalent polyether radical, such as that remaining after the reaction of the terminal hydroxyl croups or a clrunc- tional polyester glycol, having a average molecular weight in the range from about 400 to about 6,000, R is a hydrocarbon radical derived from terephthalic acid or isophthalic acid, or a reactive derivative of either of these acids, and D is a divalent radical derived from 1,4-butanediol or 1,4-butenediol; provided, said short chain units amount to between about 30E and about 855 by weight of the copolyester; and b) between about 0.1 and about 25% by weight of said copolyester of polyvinylpyrroli done. In preferred embodiments compositions of the invention also include: a) between about 0.05 and about 5% by weight of said copolyester of cyanoguanidine or guanidine stabilizer of the general formula EMI3.1 Formula III where n is an integer between 2 and about 20; ; b) between about 0.1 and about 5E by weight of said copolyester of diphenylamine derivative of tne general formula Formula V EMI3.2 where R and R1 are methyl or phenyl; and c) between about 0.05 and about 3% by weight of said copolyester of phosphorus compound of one or more of the formulas: EMI4.1 <tb> <SEP> M\&num;mopxO¸t <tb> i) <tb> <SEP> tO <SEP> Formula <SEP> V <SEP> tOt <tb> <SEP> t <tb> where t represents a tertiary butyl radical Formula VI EMI4.2 where R represents an alkyl radical aving from 6 to about 22 carbon atoms or a hydrocarbon radical of the structure EMI4.3 where t represents a tertiary butyl radical or EMI4.4 Formula VII where each of R and R1 independently represents a hydrocarbon radical selected from the group consisting of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms and R3 represents hydrogen or a hydro carbon radical selected from the group consisting of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms. In further preferred embodiments of the in vent on, at least about 80% of the R groups of formulas I and II are hydrocarbon radicals remaining after re- moval Gf carboxyl groups from terephthalic acid, between about 10 and about 40%, more usually between about 20 and about 30%, of the D groups of Formula II repre- sent divalent radicals remaining after removal of hy- droxyl groups from 1,4-butenediol and short chain its amount to between about 40% and about 65E bv weight of the copolyester. Detailed Description of the Invention The long chain ester units of the product of the invention are the reaction product of a long chain glycol with terephthalic acid or isophthalic acid. The long chain glycols are poly(alkylene oxide) glvcols having terminal (or as nearly terminal as pos- sible) hydroxyl groups and hydroxyl numbers between about 18 and about 280 as determined in accordance wit ASTM test method E-222. Corresponding number average molecular weights are between about 400 and about 6,000. Number average molecular weight for a particular glycol may be calculated by dividing the hydroxyl number into 112,200. Glycols used in the invention preferably have a number average molecular weight between about 400 and about 6,000 as carbon to oxygen ratio of between about 2.0 to 1 and about 4.3 to 1. Representative long chain glycols available for use in making product of the invention include poly(ethylene oxide) glycol, poly(l,2- and 1,3-propylene oxide) glycol, and poly(tetramethylene oxide) glycol. Poly(tetramethylene oxide) glycol is a particularly preferred glycol for long chain ester units of the invent ion. Short chain units of product of tre invention may be made by reacting 1,4-butanediol, 1,4-butenediol or a mixture thereof with terephthalic acid or isoph- thalic acid. In preferred embodiments l,4-butenedio is used in amounts between about 10 and about 40%, more usually between about 20 and about 30%, based on the total of 1,4-butaneciol and 1,4-butenediol. In making both the long chain and short chain units of product of the invention, the use of terephthalic acid is generally preferred with tre use cf between about 1 and about 20% isophthalic acid based on the total of terephthalic acid and isophthalic acid used being preferred when product of lower flexural modulus is desired. The terms "terephthalic acid" and "isophthalic acid" as used herein are intended to include the conden- sat ion polymerization equivalent of such acids, i.e. their esters or ester-forming derivatives such as acid chlorides and anhydrides, or other derivatives which behave substantially like such acids in a polymerization reaction with a glycol. Dimethyl terephthalate and dimethyl isophthalate are for instance suitable starting materials for elastomers of the invention. Copolyester elastomer for use in the invention can be made by conventional ester interchange reaction. A preferred procedure involves heating the dimethyl ester of terephthalic acid or of a mixture of terephthalic and isophthalic acids with a long chain glycol and a molar excess of a mixture of butanediol and butenediol in the presence of a catalyst at 150 - 260 0C followed by distilling off of methanol formed by the interchange. Heating is continued until methanol evolution is complete. Depending upon temperature, catalyst and glycol excess, the polymerization is complete within a few minutes to a few hours. This procedure results in the preparatIon of a low molecular weight pre-polymer which can be carried to a desired high molecular weight copolyester by distillation cf the excess of snort chain diol in a conventional polycondensation reaction. Additional ester interchange occurs during this distilla- tion to increase the molecular weight and to randomize the arrangement of the copolyester units. Best results are usually obtained if this final distillation cr polycondensation is run at less than 1 mm pressure and 220 - 255 C for less than 2 hours in e presence of antioxidants. Most practical polymerization tech n rot: es rely upon ester interchange t complete the polyrerization reaction. In ormer to avoid excessive hcld time at high temperatures with possible irreversible thermal degradation, it is advantageous to employ a catalyst for ester interchange reactlcns. While a wide variety of catalysts can be used, organic tltanates such 25 tetrabutyl or tetraisopropyl titanate used alone or in combination with magnesium or calcium acetates are preferred. Complex titanates, such as derived from alkali or alkaline earth metal alkoxides and titanate esters are also very effective. Inorganic titanates, such as lanthanum titanate, calcium acetate/ antimony trioxide mixtures and lithium and magnesium alkcxides are representative of other catalysts which can be used. Prepolymers for product of the invention can also be prepared by a number of alternate esterification or ester interchange processes. Por example, the long chain glycol can be reacted with a high or low molecular weight short chain ester homopolymer or copolymer in the presence of catalyst until randomization occurs. The short chain ester homopolymer or copolymer can be prepared by ester interchange from either the dimethyl esters and low molecular weight diols, as above, or from the free acids with the diol acetates. Alternatively, the short chain ester Co- polymer can be prepared by direct esterification from appropriate acids, anhydrides or acid chlorines, for example, with diols or by other processes such as reaction of the acids with cyclic ethers or carbonates. Obviously the prepolymer might also be prepared by running these processes in the presence of the long chain glycol. Ester Interchange polymerizations are generally run in the melt without adder solvent, but invert solvents can be used to facilitate removal of volatile components from the mass at low temperatures. This technlcue is especially valuable during prepolymer preparation, for example, by direct esterification. However, certain low molecular weight diols, for example, butanediol in terphenyl, are conveniently removed during high polymerization by azeotropic distillation. Other special polymerization techniques, for example, interfacial polymerization of bisphenol with bisacylhalides and bisacylhalide capped linear diols, may prove useful for preparation of specific polymers. Both batch and continuous methods can be used for any stage of Co- polyester polymer preparation. Polycondensation of prepolymer can also be accomplished in the solid phase by heating finely divided solid prepclymer in a vacuum or in a stream of inert gas to remove liberated low molecular weight diol. This method has the advantage of reducing degradation because it must be used at temperatures below the softening point of the prepolymer. The major disadvantage is the long time required to reach a given degree of polymerization. Molecular weight of elastomer used in product of the invention may vary widely depending upon end use requirements. For elastomer used in product of the invention melt flow rate (MFR) is usually used as an indication of molecular weight. The actual molec- ular weight of the elastomer is not usually determined. For typical uses of product of the invention such as extrusion or molding operations elastomer used tre quently has an MFR between about 0.1 and about 50 grams/ 1C minutes (2200C, 21609) as determined in accordance with ASTM test method D-1238 although elastomer of greater MFR such as up to about 350 or more may be produced if desired. Elastomer composition of tne invention ccnt-rns between about 0.1 and about 25 weight percent (wt %) polyvinylpyrrolidone (PVP) based on copolyester, preferably between about 0.5 and about 15 wt % cn the sa-e basis. While molecular weight of PVP used in the Invention is not critical as long as the PVP cces not produce discrete particles in the blend, use of PVP having a K value not exceeding about 30 is ore: erred. PVP having a K value between about 0.5 and about 20 is especially preferred. K values mentioned herein are as determined by the Fikentscher equation (Kline, G.M., "Polyvinylpyrrolidone", Modern Plastics, Nov., 1945). Elastomer of the invention preferably also contains between about 0.05 and about 5 wt % based on polyester of cyanoguanidine (CNG) EMI9.1 or of guanidine stabilizer of the general formula EMI10.1 Formula III where n is an integer between 2 and about 20, preferably 5 or 6. Use of this type of stabilizer improves long term thermal stability of the elastomer. Use of cyanoguanidine or stabilizer of Formula III in which n is 6, i.e. 1,6 Hexamethylene-bis-dicyandiamide (F3D) is especially preferred. In preferred embodiments, elastomer composition of the invention also includes between about 0.1 and about 5% by weight of said copolyester of c-rphenylamine derivative of the general formula Formula IV EMI10.2 where R and R1 are methyl or phenyl. Preferred embodiments of the invention also include between about 0.05 and about 38 by weight of said copolyester of phosphorus compound of one or more of the formulas: EMI10.3 <tb> 4 <SEP> / <SEP> <SEP> X <SEP> t <tb> <SEP> Formula <SEP> V <tb> where t represents a tertiary butyl radical Formula VI EMI11.1 where R represents an alkyl radical having from 6 to about 22 carbon atoms or a hydrocarbon radical of the structure EMI11.2 where t represents a tertiary butyl radical or EMI11.3 Formula VII where each of R and R1 independently represents a hydrocarbon radical selected from the group consisting of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms and R3 represents hydrogen or a hydrocarbon radical selected from the group consisting of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms. Addition of these ingredients provides further unexpected improvement in thermal stability of elastomer of the invent ion. Phosphorous compounds of Formula VI suitable for use in the invention include for instance distearyl pentaerythritol diphosphite dioctyl pentaerythr itol diphosphite diisodecyl pentaerylthritol diphosphite dimyristyl pentaerythritol diphosphite bis(2,4 di-t-butyl phenyl) pentaerythritol diphosphite Of these the use of distearyl pentaerythritol diphosphite or bis(2,4 di-t-butyl phenyl) pentaerythritol dihosphite is preferred. Suitable phosphorous compounds of Formula VII for use in the invention include for instance: tris (nonyl phenyl) phosphite tris (butyl phenyl) phosphite trimethyl phosphite triethyl phosphite tris (2 ethylhexyl) phosphite triisopropyl phosphite triisoctyl phosphite diisoctyl phosphite distearyl phcsphite triisodecyl phosphite triisoctyl phosphite trilauryl phosphite tristearyl phosphite diphenyl phosphite tr iphenyl phosphite diphenyl isodecyl phosphite diphenyl isooctyl phosphite phenyl isodecyl phosphite dilauryl phosphite di-tridecyl phosphite ethylhexyl diphenyl phosphite diisoctyl octylphenyl phosphite phenyl diisodecyl phosphite Of these, use of tris (nonyl phenyl) phosphite or phenyl diisodecyl phosphite is frequently preferred. Small amounts of antioxidant stabilizer, such as between about 0.1 and about 5 wt % based on copolyester, are preferably included with the ingredients used in making copolyester for use in the invention. It is preferred that at least this small amount of antioxidant be present during polymerization of the copolyester in order to prevent excessive oxidation. Antioxidant consisting of 3,4-di-tert-butyl-4-hydroxy- hydrocinnamic acid triester with 1,3,5-tris-(2-hydroxy ethyl-s-triazine-2,4,6-(1H, 3H, 5H) trione is preferred but other suitable stabilizers may be used. Compositions of the invention may include additional conventional ingredients such as UV absorbers, e.g. benzophenones or benzotr iazoles . The prcpertres cf these ccrrpcsitions can also be modified by incorpora- tion of various conventional inorganic fillers such as carbon black, silica gel, alumina, clays and chcpped fiberglass. In general, these additives have the effect of increasing the modulus cf the material at various elongations. Compounds having a range cf hardness values can be obtained by blending hard and soft copolyesters of the invention. The copolyesters can also be compounded with other resins such as pclvvinyl chloride or polybutylene terephthalate. Suitable flame retardant additives may also be used. As mentioned above, at least small amounts of antioxidant are preferably used during polymerization of copolyester of the invention. Other essential and optional ingredients of compositions of the invention are preferably added by blending with previously polymer- ized copolyester. All such ingredients or portions thereof may, however, be present during polymerization of the copolyester so long as the polymerization reaction is not interfered with. Blending with copolyester may be carried out in any suitable manner such as in conventional mixing equipment with extrusion compounding being preferred. Elastomers of the invention exhibit superior retention of mechanical properties, especially tensile strength, and improved brittleness characteristics at elevated temperatures. Such elastomers are especially suited for use in molding various articles such as tires, hoses, drive belts, gears, etc. Such elastomers can be made in grades of low melt flow rate. This permits faster molding cycle times and allows the manr;- facture of blow molding grades of elastomers of the invention. Both cyanoguanidine (CNG) and guanicine stafri- lizers of formula III are quite effective for stabilizing elastomer of the type used in the invention. CNG will, however, plate out onto extrusion processing equipment. This results in extruded parts which have dull surfaces. Guanidine stabilizers of formula III tend to bloom, resulting in dull, greasy appearing surfaces on rnished products. Use of PVP along with CNG or stabilizer of formula III in compositions of the inventicn sub- stantially eliminates such plate-out or blooming and resulting dull surfaces on extruded products. it has further been found that PVP alone has a significant stabilizing influence on elastomers of the type described herein. Stability of elastomers of this type containing PVP or PVP plus guanidine is further improved by the use of diphenylamine and phosphorous stabilizer as described herein. EXAMPLES The following examples are intended to illustrate the invention without limiting the scope thereof. In the work presented herein, the following terms have the meanings given below. DMT - dimethyl terephthalate B1D - 1,4-butanediol BD - 1,4-butenediol Poly(THF) - poly(tetramethylene oxide) glycol of number average molecular weight 1,000 TPT - tetra isopropyl titanate Goodrite 3125 - trade name for 3,5-di-tert butyl-4-hydroxyhydrocinnamic acid triester with 1,3,5-tris-(2-hydroxyethyl)-s triazine-2,4,6-(1H, 3H, 5H) trione Naugard 445 - trade name for &alpha;,&alpha; ; - dimethyl benzyl diphenyl amine (formula IV) GT - weight percent of short cain ester units of formula II in elastomer of the invention HMBD - 1,6 Hexamethylene-bis-dicyandiamide Sandostab P - EPQ - trade name for phosphonite of formula V PVP - K - 15 polyvinylpyrrolidone CNG - cyanoguanidine Weston 618 - trade name for distearyl pentaerylthritol diphosphite Elastomer used in making the elastomer compositions referred to in the examples was commercially available elastomer (GAF Gaflex 555) having a :nelt flow rate of about 12 grams per 10 minutes (2200C, 2160g) and a GT of 62. 25% of the D groups of formula II were derived from 1,4-butenediol with the remaining 75% being derived from 1,4-butanediol. This elastomer was made from the following ingredients: Ingredient Mols Grams DMT 6.13 1189 B1D 4.98 448 B2D 2.34 206 Poly (THF) 0.65 650 Goodrite 3125 35 TPT 1.3 The elastomer described immediately above was pelleted and tumble blended with various additional ingredients as indicated in Table I below to form elastomer compositions to be tested for plate-out, gloss and hot air aging properties. Each blend tested for hot air aging was then extruded into sheets using a one inch extruder equipped with a mixing screw and operated at a temperature of 2000C. ASTM D-412 test specimens were then made of each composition by die cutting. Test specimens were placed in a hot air convection oven at 1400 and were tested initially and after one, two or three weeks in accordance with ASTM D-412. Plate-out was evaluated by visual observation of extrusion equipment. Gloss was evaluated by use of a Garner Gloss gard instrument for measuring 75 and 600 g gloss. EXAMPLE 1 In order to demonstrate the effectiveness o; PVP as a stabilizer in elastomer compositions of the invention, elastomer compositions as described in Table I were formulated and tested in accordance with ASTM D-412 with the results shown in Table I. TABLE I Composition No. 1 2 3 4 Ingredients (wt%) GAFLEX GAFLEX 555 GAFLEX 555 GAFLEX 555 555 + 4 % PVP + 10 % PVP + 15 % PVP % Retention 1 wk at 1400C Ultimate Tensile 75 79 87 Strength Elongation 11 40 26 2 % Retention 2 wks at 140 C Ultimate Tensile 14 76 81 100 Strength Elongation 0 24 15 11 EXAMPLE 2 In order to demonstrate the ability of PVP to control plate-out and gloss problems resulting from the use of CNG stabilizer, elastomer compositions were formulated and tested for plate-out and class with the results shown in Table II. TABLE II Composition Plate-Out On 750 No. Ingredients (wt %) Calendar Rolls Gloss 5 Gaflex 555 (1) None 95% 6 1 + 0.38 CNG Feavy 5-35% 7 1 + 1.5 % PVP + None 95 % 0.3% CNG 8 1 + 4.0% PVP + None 95% 0.3% CNG 9 1 + 0.2% CNG Slight 10 1 + 2.0% PVP ' None 95% 0.2% CNG 11 1 + 1.58 PVP + Very Slight 90-95% 0.375% CNG 12 1 + 1.5% PVP + None 95% 0.35% CNG EXAMPLE 3 In order to show the effectiveness of PVP in conjunction wit other stabilizers in stabilizing elastomer ccmpositions of the invention, elastomer compositions were formulated and tested with the results shown in Table III. TABLE III Bot Air Ain At 140 C % Retention After 3 Weeks Ultimate Composition Tensile No. Ingredients (wt %) Strength Elongation 13 Gaflex 555 (1) 19.5% 5 14 1 + 11* 63% 15 1 + 11 + 0.75% PVP 63% EE% 16 1 + 11 + 2.0% PVP 67% 59% 17 1 + 11 + 4.0% PVP 73% * 11 = 0.3% CNG + 1.5% Naugard 445 + 0.5% Sandostab P-EPQ EXAMPLE 4 In order to show the ability of PVP to control gloss and surface appearance problems caused by blooming of HMBD stabilizer, elastomer compositions were form ulated and tested as shown in Table IV. TABLE IV Surface 60 Sample Appearance Gloss 18 - Gaflex 555 + 1.5 % Naugard 445 + dull, 79 % 0.5 % Sandostab P-EPQ + greasy 0.5 % HMBD 19 - Gaflex 555 + 1.5% Naugard 445 + glossy 95 % 0.5 % Sandostab P-EPQ + 0.65 % HMBD + 1.5 % K-15, PVP 20 - Gaflex 555 glossy 95% EXAMPLE 5 Additional compositnons of the invention may be formulated using the ingredients shown in Table V. TABLE V Amount (wt % based Composition No. Ingredients on resin) 21 Gaflex 555 91 1,3 trimethylene-bis-dicyandiamide 1 Sandostab P-EPQ 3 Naugard 445 4 PVP 1 22 Gaflex 555 93.5 1,10 decylmethylene-bis-dicyandiamide 2.5 Sandostab P-EPQ 2.0 Naugard 445 0.5 PVP 1.5 23 Gaflex 555 89 1,16 hexadecylmethylene-bis-dicyandiamide 4.5 Sandostab P-EPQ 1.5 methylphenyl benzyl diphenyl amine 1.5 (formula IV) PVP 3.5 24 Gaflex 555 96.8 1,6 hexamethylene-bis-dicyandiamide 0.5 Naugard 445 1.5 Sandostab P-EPQ 0.5 PVP 0.7 25 Gaflex 555 98 PVP 2 EXAMPLE 6 The elastomer described above was pelleted and tumble blended with various additional ingredients as indicated in TableVibelow to form elastomer compositions. Each blend was then extruded. into sheets using a one inch extruder equipped with a mixing screw and operated at a temperature of 2000C. ASTM D-412 test specimens were then made of each composition by die cutting. Test specimens were placed in a hot air convection oven at 1450C and were tested initially and after two weeks in accordance with ASZM 1-412. Percent elongation for each composition is reported in Table VI below. TABLE VI % retention of Additional Amount elongation aster Composition Incredients (wt%) 2 weeks (14; C) 26 none (control) 11.5 27 PVP 4.0 48 CNG 0.35 Naugard 445 1.5 Weston 618 0.5 28 PVP 1.5 100 CNG 0.35 Naugard 445 1.5 Weston 618 0.5 EXAMPLE 7 The elastomer described above may be pelleted and tumble blended with various additional ingredients as indicated in Table VII below to form elastomer compositions of the invention. Such compositions may then be extruded or molded to form desired end products. TABLE VII Amount Additional (wt % based Composition Ingredients on resin) 29 1,3 trimethylene-bis-dicyandiamide 1 Distearyl pentaerythritol diphosphite 3 Naugard 445 4 PVP 1 30 1,10 decymethylene-bis-dicyandiamide 2.5 bis(2,4 di-t-butyl phenyl) 2.0 pentaerythritol diphosphite Naugard 445 0.5 PVP 5.0 31 1,16 hexadecymethylene-bis-dicyandiamide 4.5 Dioctyl pentaerythritol diphosphite 1.5 methylphenyl benzyl diphenyl amine 1.5 PVP 10.0 32 1,5 pentamethylene-bis-dicyandiamide 0.5 Naugard 445 1.5 Diisodecyl pentaerythritol diphosphite 0.5 PVP 15.0 33 HMBD 0.35 Naugard 445 1.5 Distearyl pentaerythitol diphosphite 0.05 PVP 20.0 34 HMBD 3.0 Naugard 445 3.0 Dimyristyl pentaerythitol diphosphite 2.5 PVP 25.0 EXAMPLE 8 The elastomer described above may be pelleted and tumble blended with various additional ingredients as indicated in Table VIII below to form elastomer compositions of the invention. Such compositions may then be extruded or molded to form desired end products. TABLE VIII Amount Composition Additional (wt % based Ingredients on resin) 35 1,3 trimethylene-bis-dicyandiamide 1 Naugard 445 4 Diphenyl isodecyl phosphite 3 PVP 1 36 1,10 decylmethylene-bis-dicyandiamide 2.5 Naugard 445 0.5 Ethylhexyl diphenyl phospite 2.0 PVP 5.0 37 1,16 hexadecylmethylene-bis-dicyandiamide 4.5 methylphenyl benzyl diphenyl amine 1.5 Distearyl phospite 1.5 PVP 10.0 38 1,5 pentamethylene-bis-dicyandiamide 0.5 Naugard 445 1.5 Triethyl phospite 1.5 PVP 15.0 39 HMBD 0.35 Naugard 445 1.5 Tris(nonylphenyl) phospite 0.5 PVP 20.0 EXAMPLE 9 Elastomer compositions may also be formulated which are similar to those mentioned above but which use elastomers in which R groups of Formulas I and II are hydrocarbon radicals remaining after removal of carboxyl groups from terephthalic acid, D groups of formula II are divalent radicals remaining after reproval of carboxyl groups from 1,4-butanediol and G of formula I is a divalent radical remaining after removal of terminal hydroxyl groups from poly(tetra- methylene oxide) glycol. Such elastomers are available for example from E. I. duPont de Nemours and Company in several GT grades under the tradename -ytrel. While the invention has been described stove with respect to preferred embodiments thereof, it will be understood by these skilled the art that various changes and modifications may be made without departing from the spirit or scope of the invention.

Claims: CLAIMS: 1. Thermoplastic elastomer composition consisting essentially of: a) segmented thermoplastic copolyester elastomer consisting essentially of a multiplicity of recurring long chain ester units and short chain ester units joined head to tail through ester link- ages, said long chain units being repre- sented by the formula EMI27.1 Formula and said short chain units being repre- sented by the formula EMI27.2 Formula II where G is a divalent radical remainin after the removal of the terminal hy droxyl groups from a difunctional polyether glycol having a number average molecular weight in the range from about 400 to about 6,000, R is a hydrocarbon radical remaining after removal of the carboxyl groups from terephthalic acid or isophthalic acid, td D is a divalent radical remaining aster removal of hydroxyl groups from 1,4-butanediol or 1,4-butenediol; provided, said s"ort chain units amount to between about 30% and about 85% by weight of the copolyester; and b) between about 0.1 and about 25% by weight of said copolyester of polyvinylpyrroli- done. 2. Elastomer according to Claim 1 wherein between about 10% and about 409 of the D groups represent divalent radicals remaining after removal of hydroxyl groups from 1,4-butenediol. 3. Elastomer composition according to either of Claims 1 or 2 which also includes between about 0.05 and ac'rt 5% by weight of said ccpolyester of cyanoguanicine or guanidine stabilizer of the general formula EMI28.1 Formula III where n is an integer between 2 and about 20. 4, Elastomer composition according to Claim 3 wherein the guanidine stabilizer is cyanoguanidine. 5. Elastomer composition according to any of Claims 1-4 which also includes: a) between about 0.1 and about 5% by weight of said copolyester of diphenylamine derivative of the general formula Formula IV EMI28.2 where R and R1 are methyl or phenyl; and b) between about 0.05 and about 3% by weight of said copolyester of phosphorus compound of one or more of the formulas: : EMI29.1 <SEP> t <SEP> t, <tb> io;,P <SEP> <tb> <SEP> tOo <SEP> Forniula <SEP> V <tb> where t represents a tertiary butyl radicals Formula VI EMI29.2 where R represents an alkyl radical having from 6 to about 22 carbon atoms or a hydrocarbon radical of the structure EMI29.3 where t represents a tertiary butyl radical or EMI29.4 Formula VII where each of R and R1 independently represents a hydrocarbon radical selected from the group consisting of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms and R3 represents hydrogen or a hydro- carbon radical selected from the group consistIng of alkyl, aryl and alkyl/aryl hydrocarbon radicals having from 1 to about 22 carbon atoms. 6. Elastomer according to any cf Claims I or 3-5 wherein the D groups represent divalent radicals remaining after removal cf hydroxyl groups from 1 4-butanediol. 7. Elastomer composition according to any of Claims 1-6 wherein G is a divalent radical remaining after removal of terminal hydroxy groups from a difunctional polyether glycol having a carbon to oxygen ratio between about 2.5 and about 4.3 to 1. 8. Elastomer composition according to any of Claims 1-7 wherein at last about 80% of the R groups of formulas I and II are hadrocarbon radicals remaining after removal of carboxyl groups from terephthalic acid. 9. Elastomer composition according to any of Claims 1-8 wherein the short chain units amount to between about 40 and about 658 by weight of the copolyester. 10. Elastomer composition according to any of Claims 1-9 wherein between about 20 and about 30% of the D groups represent divalent radicals remaining after removal of hydroxyl groups from 1,4-butenediol. 11. Elastomer composition according to any of Claims 1-10 wherein G is a divalent radical reTaining after removal of terminal hydroxy groups from poly(tetra- methylene oxide) glycol. 12. Elastomer composition according to any of Claims 1-11 which alse inclL'des between about 0.1% an about 5% by weight of said copolyester of 3,5-di-tert-butyl- 4-hydroxyhydrocinnamic acid triester with 1,3,5-tris (2-hydroxyethyl)-s-triazine-2,4,6-(1H, 3H, 5H) trione. 13. Elastomer composition according to any of Claims 1-12 wherein polyvinylpyrrolidone is present in an amount between about 0. anc about 15 wt 8 based on copolyester. 14. Elastomer composition according to any of Claims 1-13 whereIn the guanidine stabilizer is l,t hexamethylene-bis-dicyandiamide.

Inventors: GOLDER, MICHAEL D., GROMELSKI, STANLEY J. JR.
Applicants: HOECHST CELANESE CORPORATION
Application year: 1984
Main classification: C08L67
IPC codes: C08K5, C08L67