IMPACT RESISTANT POLYAMIDE COMPOSITION

Abstract: The present invention relates to a composition comprising at least one polyamide, a non-functionalized olefinic polymer, and a functionalized block copolymer, comprising poly(ethylene/butylene) mid-blocks and poly(styrene) end blocks. The composition preferably comprises a fibrous filler of reinforcement.

Description: IMPACT RESISTANT POLYAMIDE COMPOST,TI nM BACKGROUND OF THE INVENTION This invention relates to a composition comprising a polya ide, a non-functionalized olefinic polymer, and a functionalized block copolymer; and more particularly, the functionalized tri-block copolymer comprising a tri-blocJ copolymer which comprises poly(styrene) end blocks and poly(ethylene/butylene) mid-blocks. Polyamide resins, known under the generic name nylon, are noted for a number of their properties such as hardness, high tensile strength, toughness, and rigidity. Although polyamide can be so characterized, there have been continuing attempts to improve the toughness properties of compositions containing polyamides. For the purpose of the present invention, copolymer, block copolymers and graft copolymers are defined in F. . Billmeyer, Jr., Textbook of Polymer Science. 2nd edition, Chapter 11, Wiley-Interscience, a Division of John Wiley and Sons, Inc. Graft copolymers are defined in Billmeyer at pages 350-351 as sequences of one monomer which are "grafted" to the "backbone" of a second monomer type. In the present invention, the backbone of the graft copolymer can itself be a copolymer including a block copolymer. Reference is made to copending ϋ. S. Serial No. 303,038, published as PCT US88/02658 which discloses a composition comprising polyamides and functionalized olefinic polymer. The prior art relating to high impact resistant polyamide compositions has recognized the use of polymeric impact modifiers. Such polymers include polyolβfins which are typically βthylβnβ based copolymers and ethylβne based graft copolymers. Improved impact resistance occurs by grafts between the polyamide and a reactive moiety along the backbone of the copolymer chain or a reactive moiety grafted to the copolymer chain. The graft reaction typically takes place at an amine (or amino) end group on the polyamide, i.e., polycaprolactam chain. These types of compositions are typified by the disclosures in ϋ. S. Patent Nos. 3,388,186; 3,456,059; 3,963,799; 3,976,720; 4,305,865; 4,339,555; and 4,427,832, and in articles such as Stinson, Nylon impacted resistance tailored to user need. September 22, 1986. U. S. Patent 4,174,358 is directed to a composition of a polyamide and a polyolefin impact modifier which achieves adhesion by sites which adhere to the polyamide matrix resin. The use of nylon having excess amine end groups used in a combination with impact modifiers is disclosed. U. S. Patent 4,594,386 discloses compositions of polyamides and ethylene-propylene grafted with maleic anhydride which have improved low temperature impact resistance. U. S. Patent No. 4,537,929 discloses a glass filled polyamide and an adduct of a polyethylene polymer and an alpha, beta-ethylenically unsaturated dicarboxylic acid compound which can include an ethylene-propylene maleic anhydride graft copolymer. The Shell Chemical Company has published a Technical Bulletin, fiafcaff*' 1512&1X BufcfcSΣ, SC 1592- 87, printed 12/87, (hereby incorporated by reference). This Bulletin discloses compositions of nylon 6 or nylon 6,6 containing a maleic anhydride functionalized tri-block copolymer consisting of polystyrene end blocks, and poly(ethylene/butylene) mid-block. The Bulletin discloses compositions of nylon 6 or nylon 6,6 and up to 30% by weight of Kratoi® G 1651 rubber. Krator® G 1651 is a nonfunctional!zed tri-block copolymer consisting of polystyrene end blocks, and poly(βthylenβ/butylene) mid-blocks. This material is disclosed in The Shell Chemical Company Bulletin, Shell, Kraton® Polymers for Modification of thermoplastics. (hereby incorporated by reference) . SUMMARY OF THE INVENTION The present invention relates to a composition comprising at least one polyamide, a non-functionalized olefinic polymer, and a functionalized block copolymer, comprising poly(ethylene/butylene) mid-blocks and poly(styrene) end blocks. The composition preferably comprises a fibrous filler or reinforcement. By functionalized it is meant that the copolymer has radicals or groups which are covalently reactive with the polyamide including the polyamide end groups. By non-functionalized groups it is meant that the copolymer has no radicals or groups which are covalently reactive with the polyamide including polyamide end groups. The composition comprises from about 30 to about 96, preferably, about 84 to about 96 percent by weight of polyamide based on the weight of total polymer present. There is from about 2 to about 35, and preferably from about 2 to about 8, percent by weight of non-functionalized polymer based on the weight of total polymer present, preferably an ethylene/propylene copolymer; and about 2 to about 35, and preferably about 2 to about 8, percent by weight of a functionalized block copolymer, preferably a tri- block copolymer having poly(styrene) end blocks and poly(ethylβnβ/butylenβ) mid blocks based on the weight of total polymer present. The preferred composition further comprises up to about 60, preferably about 1 to about 60, and more preferably, about 20 to about 40 percent by weight of a fibrous filler, based on the total weight of polymer and fibrous filler. The fibrous filler preferably is glass fibers, preferably chopped glass fiber. The composition of the present invention results in articles having improved impact resistance and surface appearance. The articles have greater notched and drop weight impact resistance than articles made of corresponding composition having an amount of either a non-functionalized olefinic polymer or a functionalized block copolymer equal to the combined amount in the composition of the present invention. It is believed that the combination of the random copolymer and the functionalized block copolymer results in improved impact resistance. Articles molded from the composition of the present invention had a smooth, uniform surface appearance with no apparent flow lines and were superior to articles molded from a composition made with an amount of either the non-functionalized olefinic polymer or a functionalized block copolymer equal to the combined amount in the composition of the present invention. The compositions of the present invention are stable during processing. They can be extruded at temperatures up to about 550 * F (288'C) and in the range of about 500'F as (260'C) to about 550'F (288*C); and molded at temperatures up to about 580*F (304 * C) and in the range of about 530*F (277*C) to about 580*F (304 # C) without discoloration and with maintenance of physical properties. The compositions retain satisfactory physical properties when tested after being heated to temperatures up to 210*C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a composition comprising at least one polyamide, a non-functionalized olefinic polymer, and functionalized block copolymer. There is from about 30 to about 96, preferably greater than about 50 up to about 90, more preferably from about 70 to about 90 weight percent of at least one polyamide in the composition. Polyamides suitable for use herein include the long chain polymeric amides having recurring amide groups as part of the polymer backbone and preferably having a number of average molecule weight, as measured by end group titration of about 15,000 to 40,000. The polyamides suitable for use herein can be produced by any conventional process known in the art. Non-limiting examples of such polyamides are: (a) those prepared by the polymerization of lactams, preferably epsilon-caprolacta (nylon 6); (b) those prepared by the condensation of a diamine with a dibasic acid, preferably the condensation of hexamethylene diamine with adipic acid (nylon 6,6), the condensation of hexamethylene diamine with sebacic acid (nylon 6,10) and polytβtra ethylene adipa ide (nylon 4,6); and (c) those prepared by sel -condensation of a ino acids, preferably self-condensation of 11- a inoundecanoic acid (nylon-11) , nylon 12 ; or random, block, or graft interpolymers consisting of two or more of these polyamides. λ useful copolymer is the copolymer of caprolactam, hexamethylene diamine and adipic acid (nylon 6,66). Polyamides such as nylon-6, nylon 4,6, or nylon 6,6, and copolymers such as nylon 6,66 can contain a variety of terminal functionality, including: (a) a carboxyl group attached to both ends of the polyamide chain (acid terminated) ; (b) a carboxylic acid group attached to one end and an amine group attached to the other end of the polyamide chain (the "capped" end) ; (c) an amino group attached to both ends of the polyamide chain (amine terminated) ; and (d) a carboxyl group attached to one end and an amine group attached to the other end of the polyamide chain ("balanced" termination) . The present invention includes polyamides such as polycaprolactam having at least two end groups as amine end groups. While polyamides are typically linear molecules having only two end groups, polyamides such as polycaprolactam can be made with side chains by the use of a branching material such as a multifunctional reactive moiety. Such polycaprolactam molecules having at least two of its end groups as amine end groups are included in the description of excess amine terminated polycaprolactams of the present invention. Such amine terminated polycaprolactam has from about 3 to about 97 mole percent of the polycaprolactam molecules having at least two end groups as amine end groups. Polycaprolactams having "excess" amine termination are polycaprolactams having molecules with more than 50 mole percent and preferably about 60 to about 97 mole percent of the total number of end groups as amine end groups. Amine end group termination is typically produced by including an excess of diamines during polymerization, λ preferred diamine is hexamethylene diamine. Other examples of diamines suitable for use herein include tetramethylene diamine, penta ethylene diamine, octamethylene diamine, decamethylene diamine; and dodecylamine. λ preferred polyamide is polycaprolactam. The polycaprolactam, if unwashed, can contain up to about 15 percent, and typically from about 8 to about 12 percent by weight based on the weight of polycaprolactam, of caprolactam monomer or water extractable caprolactam oligomers. The composition of the present invention includes a non-functionalized olefinic polymer. There is from about 2 to about 35, preferably about 5 to about 25, and more preferably, about 5 to about 20 weight percent of the non-functionalized block copolymer based on the total polymer. Preferably, the non-functional olefinic polymer is fully saturated. Preferred non-functional olefinic polymers are copolymers of an ethylene and an alpha- olefin other than ethylene. The alpha-olefin preferably is an alpha-olefin selected from at least one C3-C5 alpha-olefin, with propylene being most preferred. Other C3-C6, such as 1-butene, 1-pentane, and 1-hexene can be used. The copolymer can contain other monomers such as dienes. Preferred dienes include butadiene, 1,4-hexadiene, dicyclopentadiene, methylene norborene, cyclooctadiene and the like. The diene can be conjugated or nonconjugated. Preferred copolymers include ethylene propylene copolymers (EP) and ethylene propylene diene copolymers (EPDM) . Useful non-functional olefinic copolymers of ethylene and an alpha-olefin contains from about 30 to about 60 and preferably about 40 to about 45 weight precent of the alpha-olefin based on the ethylene. The copolymer has a number average molecular weight of from about 2,000 to about 100,000, preferably about 2,000 to about 65,000, more preferably about 5,000 to about 35,000, and most preferably about 5,000 to about 20,000. The most preferred non-functional olefinic copolymers are EP and EPDM copolymers sold by Exxon Chemical Company under the trademarks Vistalor^ and Exxβlox®. Useful EP copolymers typically have a Mooney viscosity according to ASTM D-1646 using radial cavity dies (ML+4 at 125-C) of about 10 to about 75, and preferably about 10 to about 30, and a specific gravity of from about 0.86 to about 0.90. The most preferred EP copolymer is Exxβloi® PE 901 reported to have a Mooney viscosity of 22.0-25.0; and ethylene to propylene weight ratio of 55/45; and a narrow molecular weight distribution. Useful EPDM copolymers typically have a Mooney viscosity (ASTM D-1646, as above) of about 10 to about 80, and preferably about 45 to about 65. A preferred EPDM copolymer is Vistalon R 7000. The composition comprises also includes a functionalized tri-block copolymer comprising poly(ethylene/butylene) mid-blocks and poly(styrene) end blocks. There is from about 5 to about 50 percent by weight of the poly(styrene) end blocks, from about 50 to about 90 percent by weight of the poly(βthylene/butylene) block, and up to about 5 percent by weight of the functionalized groups, in the functionalized block polymer. Preferably, the mid- blocks comprise about 25 to about 50, more preferably about 30 to about 45, and most preferably about 35 to about 40 percent by weight of butylene and corresponding amounts of ethylene. The butylene can be derived from either 1,2 or 1,4 butadiene. The solution viscosity in toluene at 25*C is preferably from about 2500 to about 25,000 centipoises (CPS) and more preferably, from about 3000 to about 9000 CPS. There is from about 2 to about 35, preferably about 5 to about 25 and more preferably about 5 to about 20 weight percent of the functionalized block copolymer based on the total polymer. The functionalized tri-block copolymer has an average of at least two, preferably from about 2 to about 10, more preferably about 2 to about 6, and most preferably about 2 to about 4 reactive moieties per copolymer molecule which is preferably grafted to the copolymer. It is believed that greater than one reactive moiety groups on the reactive copolymer enhances the crosslinking between the amine end groups of the polyamide and the reactive copolymer. The reactive moiety is preferably a carboxyl or carboxylate functionality, which can be supplied by reacting the tri-block copolymer with an unsaturated reactive moiety taken from the class consisting of alpha, beta- ethylenically saturated dicarboxylic acids having from 4 to 8 carbon atoms, or derivatives thereof. Such derivatives include anhydrides of the dicarboxylic acids, or the metal salts of the acids, or the monoester of the dicarboxylic acid having from 0 to 100 percent of the carboxylic acid groups ionized by neutralization with metal basic salt, and the like. Illustrative of such acids and derivatives are maleic acid, maleic anhydride, maleic acid onoethyl ester, metal salts of maleic acid monoethyl ester, fumaric acid, fumaric acid monoethyl ester, itaconic acid, vinyl phthalic acid, metal salts of fumaric acid monoethyl ester, monoesters of maleic or fumaric acid or itaconic acids where the alcohol is methyl, propyl, isopropyl, butyl, isobutyl, hexyl, cyclohexyl, octyl, 2-ethyl hexyl, decyl, stearyl, ethoxy ethyl, ethoxy ethyl, hydroxy or ethyl, and the like. The reactive moiety can be grafted to the copolymer by any well- known grafting process. Alternatively, the reactive moiety can be copolymerized into the backbone of the copolymer. The reactive copolymer can include one or more types of reactive moieties. There is from up to about 60, preferably about 1 to about 60, more preferably about 20 to about 40 weight percent, based on the total weight of the polymer, of a fibrous filler preferably glass fibers, which are preferably chopped or short fibers. The glass fiber reinforcement is preferably fiber which is at least about 0.005 inch (0.0127cm) in average length in the final product. These short lengths of fibrous reinforcement are obtained because of the characteristics of the processing apparatus used to compound or blend this reinformcent with the thermoplastic resin. Typically, the glass fibers initially blended into the composition are from about 1/16 to l inch (0.159 to 2.54cm) in length, and preferably about 1/8 (0.318cm) to 1/4 inch (0.318 to 0.635cm) in length. For example, if fibers 1/8 inch (0.318cm) or longer are placed in the feed hopper of a single screw extruder along with the resin, the fibers will ordinarily be broken down into lengths shorter than the original 1/8 inch (0.318cm) starting length because of abrasion, shear, turbulence, mechanical work performed upon the fibers. Longer lengths (e.g. means lengths longer than 0.005 inch (0.0127cm) in a major portion of the short fiber reinforcement) may be retained by minimizing the amount of shear or mechanical breakdown of fiber length, with some sacrifice in homogeneity or prolonged processing times. Another processing machine which may be used to blend and/or manufacture the short fiber-filled resinous sheet is a twin screw extruder. In this case, the filamentary reinforcing material may be added to agitated heat plastified polymer between the screws of the extruder through a feed port such as a volatile (vent) port. In the latter case, the filamentary reinforcing material may be fed to the twin screw extruder in the form of yarn or roving, and the short fiber lengths would be obtained by the mechanical breakup performed by the mixing action of the screws. Glass fibers normally used for reinforcement of thermoplastics can be treated or coated with a sizing composition. Standard sizing agents usually consist of several components, each of which possesses a distinct function. For example, a binder gives the glass fiber strand integrity for workability and prevents fuzzing and aids in distribution of the sizing agent; a lubricant prevents destruction of the strand by -π- abrasion of the individual filaments against each other and against fiber handling equipment; a coupling agent assists in obtaining greater adhesion between the glass fibers and the polymeric composition. The weight ratio of non-functional olefinic polymer to functionalized block copolymer is preferably about 1:5 to about 5:1, more preferably from about 1:5 to about 2:1 and most preferably about 1:2 to about 1:1. The composition of this invention can also contain -,ne or more conventional additives which do not materially affect the impact properties of the composition of the present invention such as stabilizers and inhibitors of oxidative, thermal, and ultraviolet light degradation, lubricants and mold release agents, colorants, including dyes and pigments, fla e-retardants, particulate and fibrous fillers and reinforcements, nucleators, plasticizers, and the like. These additives are commonly added during the mixing strip. Representative oxidative and thermal stabilizers which may be present in blends of the present invention include Group I, metal halides, e.g., sodium, potassium, lithium with cuprous halides, e.g., chloride, bromide, iodide; hindered phenols, hydroquinoneβ, and varieties of substituted members of those groups and combinations thereof. Representative ultraviolet light stabilizers include various substituted resorcinols, salicylates, benzotriazoles, bβnzophβnones, and the like. Representative lubricants and mold release agents include stearic acid, stearyl alcohol, and stearyl amides. Representative organix dyes include nigrosine, while representative pigments, include titanium dioxide, cadmium sulfide, cadmium selenide, phthalocyanineβ, ultramarine blue, carbon black, and the like. Representative fillers include carbon fibers, mineral fibers, thermotropic polyester fibers, aramid fibers, amorphous silica, asbestos, calcium silicate, aluminum, silicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, feldspar, and the like. As recited about, glass fiber filler is preferred. Representative plasticizers include lactams such as caprolactam and lauryl lactam, sulfonamides such as o,p-toluenesulfonamide and N-ethyl, N-butyl benzlsulfonamide, o,p-toluenesulfonamide and other plasticizers known in the art. Representative particulate filler may be selected from a wide variety of minerals, metals, metal oxides, soliceous materials, metal salts, and mixtures thereof. These fillers may optionally be treated with various coupling agents or adhesion promoters, as is known to those skilled in the art. Examples of fillers included in these categories are alumina, aluminum hydrates, feldspar, asbestos, talc, calcium carbonates, clay, carbon black, quartz, novaculite and other forms of silica, kaolinite, bentonite, garnet, mica, saponite, beidellite, calcium oxide, calcium hydroxide, etc. The foregoing recited fillers are illustrative only and are not meant to limit the scope of fillers that can be utilized in this invention. The particulatβ filler may be added to the thermoplastic resin before, during, or after the addition of the short glass fibers to the resin. Thus, for example, filler and resin pellets may be fed to the feed hopper of a single screw exdtruder; the mixture is blended and conveyed towards the die. Short glass fibers can be added to the molten mixture at a vent hole or other such opening downstream of the feed hopper, and the mixture then extruded into pellets. functionalized olefinic copolymer, and the functionalized block copolymer in a screw extruder or other conventional plasticating device such as Brabender, Banbury mixer, mill or the like. The composition can be melt blended at a temperature greater than the melt temperature of the polyamide and +hβ functionalized copolymer. Preferably, the composition is melt blended at a temperature at least about 10*F to about 75'F (5.6'C to 41.6'C) and more preferably, about 10*F to about 30*F (5.6*C to 16.6*C) above the melt temperature of the highest melt temperature polyamide in the composition. λ preferred method is to melt blend the composition in an extruder above the polymer melt temperature. It is preferred to feed the fiberglass into the mixture through a side port. The fiberglass can be fed in a second extrusion pass. If the fiberglass is to be fed into the throat of the extruder, it is preferred to first pre-blend the polymer and impact modifier. Preferred extruder conditions for polyepsiloncaprolactam are above 260*C temperature profile. λ preferred composition comprises from about 84 to about 96 percent by weight of polyamide, from about 2 to about 8 percent by weight of non-functional olefinic polymer and about 2 to about 8 percent by weight of functional block copolymer. Optionally, there is from about 20 to about 40 percent by weight of glass fiber. The compositions can be made into a wide range of useful articles by conventional molding methods employed, in the fabrication of thermoplastic articles, i.e., as molded parts, extruded shapes, e.g., tubing, films, sheets, fibers, laminates and wire coating. "Molding" means forming an article by deforming the blend in the heated plastic state. The Examples set forth below illustrate the nature of the invention and the manner of carrying it out. The invention should not be considered as being limited to the details of the Examples. All parts are percents by weight unless otherwise indicated. The Examples show improved notched Izod impact resistance when combining a polyamide with the non- functionalized olefinic polymer and functionalized block copolymer compound compared to a composition containing an amount of either non-functionalized olefinic polymer or functionalized block copolymer alone, equal to the amount of the olefinic and block copolymer. The compositions in the following Examples were generally prepared by first dry blending the materials. The dry blended material was melt extruded at about 450'F to about 550* F (232'C to 288*C) in a three stage, 2-1/2 inch (6.35cm) diameter, Egan single screw extruder, at a rate of about 180 (81.7 kg) pounds per hour. When used, short glass fibers were fed into the side of the extruder in the second stage. Extrudate strands were rapidly passed through a water bath. The strands were passed through a palletizing machine and the pellets were collected. Test specimens were injection molded at a temperature typically from about 10*F to about 30*F (5.6*C to 16.6'C) above each composition's melting point. The mold temperature was maintained at about 160-180'F (7l'C to 82*C). The molding cycle was 10 to 30 seconds forward ram, and 10 to 25 seconds on hold. The melt index was determined according to a modified ASTM D-1238 Condition Q Procedure. The resin was preheated for 5 minutes at 280*C; and a 3000 gram weight was used. Resin was allowed to flow for 1 minute; followed by measuring the weight resin flow during the next minute. Results are reported in gra s/per 10 minutes. The notch Izod impact values were tested according to ASTM D-256 notched Izod using 1/8 inch (0.318cm) or 1/4 inch (0.635cm) test specimens as indicated. The tensile strength, modulus, and elongation were tested according to ASTM D-638, and the flexural properties were tested according to ASTM D- 790. Drop weight impact was tested according to ASTM D-3029. Heat Deflection Temperature was tested according to ASTM D-646 at 264 psi 1812 k and 66 psi 455 kPa. The amine terminated polyepsiloncaprolactam had excess amino end groups using hexamethylene diamine. The amine terminated polycaprolactam was polyepsiloncaprolactam having about 80-85 mole percent amino end groups and a formic acid viscosity (FAV) of 57 unless otherwise indicated. The balance terminated polycaprolactam was polyepsiloncaprolactam having 50 mole percent acid end groups and 50 mole percent amine end groups with a formic acid viscosity (FAV) of 70 unless otherwise indicated. The functionalized block copolymers used in the Examples was Kratoπ& FG 1901 described above. This is reported to be a low molecular weight tri-block copolymer of styrenβ-βthylenβ/butylenβ-styrenβ blocks; having a low molecular weight, a styrene to ethylene/butylene ratio of 28/72; 2 weight percent of functionally bound maleic anhydride; and a glass transition temperature of the ethylene butylene block of -42*C. The.non-functionalized olefinic polymer used includes Vistalori®730 and 878 and Exxβloι®90l ethylene-propylene copolymer (EPM) sold by the Exxon Chemical Co. Viβtalon©730 is reported to have an ethylene content of 45 weight percent, a corresponding amount of propylene and a Mooney viscosity at 127*C of 14. The is reported to have an ethylene content of 50 weight percent, a corresponding amount of propylene and a Mooney viscosity at 127*c of 25. The Exxelor « y 901 is reported to have an ethylene content of 55 weight percent, and a Mooney viscosity of 22-26. All are reported to have a narrow molecular weight distribution. The glass filler (fiberglass) used in the Examples was PPG 3540 short (1/8 inch (0.318cm) long) type E 0 glass (boroβilicate) , sized for nylon, and having a filament diameter of about 10 μm. EXAMPLE 1 Example 1. and Comparative Examples 1-5 contained 55.61 weight percent of balanced nylon 6; 1 weight 5 percent of a masterbatch of 20 weight percent sodium stearate and 80 weight percent nylon 6; 6.1 weight percent tβtrakiβ [mβthylβne 3-(3', 5'-di-tβrt-butyl- 4'hydroxyphenyl) propionate] made by Ciba Geigy Corporation as Irganox^' 1010; 0.29 percent Ultranox 11 20626 sold by Borg-Wamβr and understood to be biβ[2,4,- di-t-butyl penyl] pentaerthritol dyphoβphoβphitβ; and 10 percent of an impact modifier which was varied. All used PPG 3540 short fiberglass fiber. The impact modifiers used include Kraton® 1901X; a~-<~ Vistalon MD 730 2D (described above). Viβtalor 746 made by the Exxon Chemical Co. and Xratoπ^l651 and 1650 made by the Shell Chemical Co. were used in the Comparative Examples. Vistalor^746 is malβatβd functionalized 30 ethylene/propylene copolymer sold by the Exxon Chemical Co. and reportedly has an ASTM D-1646, radial cavity die Mooney Viscosity (ML1 at 125-C) of 17±5, an ash weight percent of 0.2, a mixumum water content of 0.5 weight percent. 35 Kratori® 1651 is reported to be a nonfunctionalized tri-block copolymer having poly(styrene) end blocks and poly(ethylβne/butylene) mid-blocks and reported to have a styrene/rubber ratio of 32/58, and a glass transition temperature of -42*C and is characterized as having high molecular weight (polystyrene block molecular weight of about 30,000). Krator$ y 1650 is similar to 1651 except that the styrene to rubber ratio is 29/71 and it has a medium low molecular weight with the styrene block molecular weight being about 10,000 (Shell KratonS*Polymers for Modification of Thermoplastics Bulletin, supra) . Results are summarized in Table 1 below: Xafelft-l £&_α £2Ϊ£_L1 COBPt2. QBP.3 Nylon 6 (balanced) Fiberglass Kraton 1901 Kraton 1651 Kraton 1650 Viβtalon 730 Viβtalon 746 Tensile Str. 21.8 (psi xlO 3 ) Flex. Str. 33.0 (psi x 10 3 ) Flex. Mod. 1.1 1.1 (psi x 10 3 ) Flex Mod. 1.0 1.0 (psi x 10 6 ) Notched Izod 5.3 2.6 5.0 4.1 (ft-lb/in of rotch) Drop Weight 38 23 27 32 Impact (in/lb) M.I. 2.3 1.6 A review of the results of Table 1 illustrates that the combination of the non-functional copolymer and the functionalized tri-block had a combination of high Notched Izod and Drop Weight impact resistance. Small handle drill housings were injection molded on a 200 ton injection molding machine at about 565*Fd (296*C) using the composition of Example 1 and Comparative Examples 2 and 3. The surface appearance of the Example 1 housing was very good. In comparison, the surfaces of housings made from Comparatives 2 and 3 had apparent flow marks, surface whitening and other imperfections due to stress and an unstable composition. It is believed that the Vistalon®and Kratorr^in the Comparative Examples phase separated from the matrix nylon and could easily be removed under surface stress resulting in a white appearance. EXAMPLE 2 The compositions of Example 2 and Comparative 4 were prepared in accordance with the method of Example 1. Results are summarized in Table 2. The compositions contain the same stabilizers, in the same amounts as Example 1. Tafele z Com .4 Ex.2 Nylon 6 51.61 51.61 (balanced) Fiberglass 33 33 Kraton 1901 7 7 Vistalon 746 7 Vistalon 878 7 Tensile str. 20 18.4 psi x 10 3 ) Flex. Str. 26.2 27.0 (psi x 10 3 ) Flex. Mod. 1.0 0.94 (psi x 10 3 ) Notched Izod 4.3 5.8 (ft-lb/in) Drop Wt. 43 76 Impact (in/lb) EXAMPLES 3 ANn Examples 3 and 4 and Comparatives 5-8 were made in accordance with the process recited above with specific compositions and properties summarized in Table 3 below: Table 3 Comp. Ex. Ex. Comp. Comp, Comp. 5 3 4 6 7 8 Nylon 6 53.61 53.61 55.61 55.61 55.61 55.61 (balanced) Fiberglass 33 33 33 33 33 33 Kraton 1901 7.8 6.0 5.0 6.5 6.5 Kraton 1650 - - - 3.5 Kraton 1657 4.2 - 3.5 Vistalon 730 - 6.0 5.0 - - 10.0 Tensile Str.21.7 21.4 23.0 22.7 23.0 24.0 (psi x 10 3 ) FlβX. Str. 28.0 31.0 33.0 33.2 32.0 31.1 (psi x 10 3 ) Flex. Mod. 9.97 1.1 1.1 1.1 1.1 1.17 (psi x 10 3 ) Notched Izod 4.3 5.2 4.6 4.7 5.0 2.8 (ft-lb/in) Drop wt. impact (in/lb) 37 41 40 38 38 21 Drill housings molded from the compositions of Examples 3 and 4 had superior appearance compared with drill housings molded froe the compositions of Comparative examples 5-8. EXAMPLS 5 λ composition was melt blended with 83 weight percent polycaprolactam, 1.5 weight percent of the sodium stearate masterbatch (20 weight percent sodium stearate, 80 weight percent polyamide) 0.1 weight percent IrganoxG' ιoiO, and 0.4 weight percent Ultrano>® 626, 7.5 weight percent Kratoi 'FG 1901 and 7.5 weight percent Exxalor®90l. Physical properties include a tensile strength of 5959 psi; flexural strength of 11,095 psi; flexural modulus of 285,047 psi and a notched Izod impact resistance value of 2.7 foot pounds per inch of notch. EXAMPLES 6 and 7 The compositions summarized in Table 4 below were melt blended as described above. The nylon 6 was balanced polycaprolactam. The compositions all contained 1 weight percent of the sodium stearate/nylon 6 (SST) masterbatch. Comparative 10 and Example 6 contained potassium bromide and anhydrous cupric chloride heat stabilizers. Examples 6, and 7 contained 2.0 weight percent of o.p-toluene sulfonamide (o,p TS) plasticizer and Irganox^lOlO sold as a light and thermal stabilizer, as well as the stabilizer Ultranoι^626. Irganoi 1010 is tetrakis [methylene 3(3',5'-di-tert-buty1- ' hydroxy-phβny1) propionatβ]. Ultranox 626 is understood to be biβ[2,4-di-t- butyphβnyl] pentaβrthritol] diphosphite. Thermal aging tensile strength tests were conducted according to ASTM D-638 using 1/8 and 1/32 inch (0.318cm and 0.159cm) thick molded tensile bars aged at 190*C, 200*C, 2 0'C for the indicated time periods. Results in pounds per square inch (psi) are summarized on Table 4 below for the average of five samples. __£SSP-ι coBPt a Hour* Ten.Str. % Ten. Str. % (pal) Retained (psi) Retained 190'C 27485 19024 69 18945 64 23500 19672 84 13934 59 6316 26 0 5 Tafel* - EX. 6 £_£____& Hour* Ten. Str. % sac, 7 Ten. Str. % Ten. Str. % (pβi) Retained (pβi) Retained (pβi) Retained T' C ~ QQ - ς ____2 21Q - C 1/8" Sample 0 20879 20879 21735 168 21923 105 21554 99 600 22347 107 20258 97 840 18915 87 1176 19126 92 1344 18813 90 13130 50 1/32" Sample 0 17544 17544 168 20264 116 600 18215 104 18488 105 840 1176 16075 92 1344 16166 92

Claims: CLAIMS: 1. An impact-resistant composition c h a r a c t e r i z e d by: between 30 and 96 percent by weight of at least one polyamide, between 2 and 35 percent by weight of non-functional olefinic polymer, between 2 and 35 percent of functionalized block copolymer comprising poly(ethylene/butylene) blocks and poly(styrene) end blocks, and functionalized groups selected from monomers alpha,beta-ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms, at least two carboxylic acid groups, and anhydrides thereof. 2. The impact-resistant composition according to claim 1 further c h a r a c t e r i z e d by: additionally including a fibrous filler in an amount of between about 1 to 60 percent by weight based on the weight of the composition. 3. The impact-resistant composition according to claim 1 further c h a r a c t e r i z e d by: in that fiberglass used as the fibrous filler. 4. The composition according to claim 1 further c h a r a c t e r i z e d by: in that the ratio of the olefinic polymer to the functionalized block copolymer is from 1:5 to 5:1. 5. -The composition according to any preceeding claim further c h a r a c t e r i z e d by: in that the functionalized groups are grafted onto the block copolymer. 6. The composition according to any preceeding claim further c h a r a c t e r i z e d by: in that the functionalized groups are derived from maleic anhydride or maleic acid. 7. The composition according to any preceeding claim further c h a r a c t e r i z e d by: in that the polyamide comprises 3 to 97 mole percent polyamide having at least two end groups consisting of amine end groups and selected from polycaprolactam, poly(hexamethylene adipamide) , poly(tetramethylene adipamide); and that the copolymer is selected from hexamethylenadipamide, caprolactam, and mixtures thereof. 8. The composition according to claim 7 further c h a r a c t e r i z e d by: in that the olefinic polymer is a copolymer of ethylene and propylene. 9. The composition according to any preceeding claim further c h a r a c t e r i z e d by: in that the functionalized block copolymer consists of between 5 and 50 percent by weight poly(styrene) end blocks, between 50 and 93 percent by weight poly(ethylene/butylene) blocks, and up to 2 percent by weight functionalized groups.

Inventors: BHOORI YOUSUF MOHAMMED, BHOORI, YOUSUF, MOHAMMED
Applicants: ALLIED SIGNAL INC, ALLIED-SIGNAL INC.
Application year: 1990
Main classification: C08L77
IPC codes: C08K7, C08L23, C08L51, C08L53, C08L77