Heat resistant thermoplastic articles including co-stabilizers

Abstract

Disclosed is a molded or extruded thermoplastic article including a polyamide composition including (a) a polyamide resin having a melting point and/or glass transition; (b) one or more polyhydric alcohols having more than two hydroxyl groups and having a number average molecular weight (M n ) of less than 2000; (c) one or more co-stabilizer(s) (d) one or more reinforcement agents; wherein 4 mm test bars prepared from said polyamide composition, exposed at a test temperature at 170° C. for a test period of 500 hours have a retention of tensile strength, on average, of at least 50 percent, as compared with that of unexposed control of identical composition and shape.

1 - 15 . (canceled) 
     
     
         16 . A molded or extruded thermoplastic article comprising a polyamide composition comprising:
 (a) at least one polyamide resin having a melting point and/or glass transition temperature, selected from the group consisting of:
 (I) Group (III) Polyamides having the melting point of at least 210° C., and comprising: 
 (aa) about 20 to about 35 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of:
 (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and 
 
 (bb) about 65 to about 80 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of:
 (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and the aliphatic diamine having 4 to 20 carbon atoms; 
 (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; 
 
 (II) Group (IV) Polyamides comprising: 
 (cc) about 50 to about 95 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of:
 (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; and 
 
 (dd) about 5 to about 50 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of:
 (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and the aliphatic diamine having 4 to 20 carbon atoms; 
 (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; 
 
 (III) Group (V) Polyamides having the melting point of at least 260° C., and comprising: 
 (ee) greater than 95 mole percent semiaromatic repeat units derived from monomers selected from one or more of the group consisting of:
 (i) aromatic dicarboxylic acids having 8 to 20 carbon atoms and aliphatic diamines having 4 to 20 carbon atoms; 
 
 (ff) less than 5 mole percent aliphatic repeat units derived from monomers selected from one or more of the group consisting of:
 (ii) an aliphatic dicarboxylic acid having 6 to 20 carbon atoms and the aliphatic diamine having 4 to 20 carbon atoms; 
 (iii) a lactam and/or aminocarboxylic acid having 4 to 20 carbon atoms; 
 
 (IV) and mixtures of Group (III) Polyamides, Group (IV) Polyamides, and Group (V) Polyamides; 
   (b) 1 to 4 weight percent of at least one polyhydric alcohol selected from the group consisting of pentaerythritol, dipentaerythritol, tripentaerythritol, di-trimethylopropane, D-mannitol, D-sorbitol, xylitol, and mixtures thereof;   (c) 0.1 to 3 weight percent of at least one co-stabilizer having a 10% weight loss temperature, as determined by thermogravimetric analysis, of greater than 30° C. below the melting point of the polyamide resin if the melting point is present, or at least 250° C. if the melting point is not present; selected from the group consisting of secondary aryl amines, hindered amine light stabilizers, and mixtures thereof;   (d) 10 to 60 weight percent of at least one reinforcement agent; and   (e) 0 to 50 weight percent of at least one polymeric toughener comprising a reactive functional group, a metal salt of a carboxylic acid, or mixtures thereof;   
       wherein all weight percentages are based on the total weight of the polyamide composition; and wherein 4 mm test bars prepared from the polyamide composition, exposed at a test temperature at 230° C. for a test period of 500 hours, in an atmosphere of air, and tested according to ISO 527-2/1A, have a retention of tensile strength, on average, of at least 60 percent, as compared with that of an unexposed control of identical composition and shape. 
     
     
         17 . The molded or extruded thermoplastic article of  claim 16 , wherein the polyamide resin comprises a blend of two or more polyamides selected from the group consisting of Group (III) and Group (VI) Polyamides, and Group (IV) and Group (V) Polyamides. 
     
     
         18 . The molded or extruded thermoplastic article of  claim 16 , wherein the polyamide resin is selected from poly(hexamethylene terephthalamide/hexamethylene hexanediamide) (PA6T/66), poly(hexamethylene terephthalamide/2-methylpentamethylene terephthalamide) (PA6T/DT), or mixtures thereof. 
     
     
         19 . The molded or extruded thermoplastic article of  claim 16 , wherein the polyhydric alcohol is selected from the group consisting of dipentaerythritol, tripentaerythritol, and mixtures thereof. 
     
     
         20 . The molded or extruded thermoplastic article of  claim 16 , wherein the co-stabilizer is at least one secondary aryl amine. 
     
     
         21 . The molded or extruded thermoplastic article of  claim 16 , wherein the reinforcement agent is selected from the group consisting calcium carbonate, glass fibers with circular and noncircular cross-section, glass flakes, glass beads, carbon fibers, talc, mica, wollastonite, calcined clay, kaolin, diatomite, magnesium sulfate, magnesium silicate, barium sulphate, titanium dioxide, sodium aluminum carbonate, barium ferrite, potassium titanate, and mixtures thereof. 
     
     
         22 . The molded or extruded thermoplastic article of  claim 16 , wherein the polyamide composition comprises less than 25 ppm copper, as determined with atomic absorption spectroscopy. 
     
     
         23 . The molded or extruded thermoplastic article of  claim 16 , wherein the article is selected from the group consisting of charge air coolers; cylinder head covers; oil pans; engine cooling systems, thermostat and heater housings, coolant pumps, mufflers, housings for catalytic converters; air intake manifolds; and timing chain belt front covers. 
     
     
         24 . The molded or extruded thermoplastic article of  claim 16 , wherein the co-stabilizer is selected from 4,4′ di(α,α-dimethylbenzyl)diphenylamine; (poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)-imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]); (1,3,5-triazine-2,4,6-triamine, N,N′″-[1,2-ethanediylbis[[[4,6-bis[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl]imino]-3,1-propanediyl]]-bis[N′,N″-dibutyl-N′,N″-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)); di-(2,2,6,6-tetramethyl-4-piperidyl) sebacate; and mixtures thereof. 
     
     
         25 . The molded or extruded thermoplastic article of  claim 16 , wherein the test period is a long-term test period equal to, or longer than, 1000 hours. 
     
     
         26 . The molded or extruded thermoplastic article of  claim 16 , wherein the retention of tensile strength, on average, is at least 70 percent, as compared with that of an unexposed control of identical composition and shape. 
     
     
         27 . The molded or extruded thermoplastic article of  claim 16 , wherein the retention of tensile strength, on average, is at least 80 percent, as compared with that of an unexposed control of identical composition and shape. 
     
     
         28 . The molded or extruded thermoplastic article of  claim 16 , wherein the retention of tensile strength, on average, is at least 90 percent, as compared with that of an unexposed control of identical composition and shape. 
     
     
         29 . The molded or extruded thermoplastic article of  claim 25 , wherein the retention of tensile strength, on average, is at least 70 percent, as compared with that of an unexposed control of identical composition and shape. 
     
     
         30 . The molded or extruded thermoplastic article of  claim 25 , wherein the retention of tensile strength, on average, is at least 80 percent, as compared with that of an unexposed control of identical composition and shape.