MXPA98002736A - Composition of hand alternative to intempe - Google Patents

Abstract

The present invention relates to a thermoplastic molding composition, comprising: a) a polyalkyl acrylate gum not containing grafted phase, b) a polyalkyl acrylate gum grafted with poly (vinyl aromatic-co-nitrile), and c) a non-grafted poly (aromatic vinyl-co-nitrile), with the ht index of (a) to the total of (a) + (b) is from 0.15 to 0.45, the total gum content is approximately 15. at 35% relative to the total ht of (a), (b) and (c), and the average particle size of said polyalkyl acrylate gum from (a) and from (b) is approximately 0.01 to 1 micron. said polyalkyl acrylate gum, both cases and, independently, comprise polymerized alkyl acrylate with or without reticulant monomers

Description

COMPOSITION OF ALTERNATIVE HANDLE AT THE WEATHER The present invention relates to a thermoplastic molding composition based on acrylate-styrene-acrylonitrile rubber. A thermoplastic composition is described consisting of (a) a polyalkyl acrylate gum characterized by not containing any grafted phase and (b) a polyalkyl acrylate gum grafted with poly (vinyl aromatic co-nitrile) and (c) free, ie ungrafted vinyl aromatic poly (co-nitrile) having a number average molecular weight of from about 20,000 to 100,000 g / mol. The composition containing about 15 to 35% by weight of polyalkyl acrylate gum having a weight average particle size of about 0.02 to 1 microns and wherein the weight ratio between (a) and the total of ( a) + (b) is 0.1 to 0.5, it is characterized by having better physical and mechanical properties. The so-called weather-alterable ASA polymers have been known for a long time in the art - see, for example, US Pat. 3,944,631 and the documents cited therein. These polymers contain a grafted crosslinked acrylate gum phase, which is said to offer better properties. Also relevant is US Pat. 4,224,419, which described a composition that it contains a first graft copolymer, a second graft copolymer and a third hard component copolymer of styrene and acrylonitrile. The first and second grafts include both as crosslinked acrylic ester polymer substrates, the difference being in terms of their respective particle size: the first gum has an average particle diameter (mean weight) of 50-150 nm and the second It has 200-500 nm. U.S. Pat. No. 4,753,988 described a high gloss composition containing a SAN matrix and a grafted crosslinked alkyl acrylate gum. The elastomeric phase consists of (i) gum of a particle size of 0.5 to 0.8 microns and 5 to 40% of grafted phase and (ii) crosslinked gum of 0.05 to 0.2 microns and a 15 to 60% grafted phase. The inclusion of eventual comonomers, such as acrylonitrile, in the acrylate gum is described. Similarly, US Pat. No. 4,880,875, which described eventual comonomers such as acrylonitrile (AN) on a butyl acrylate (AB) substrate. Gum grafts containing comonomers have been described in US Pat. 5,120,788 and 5,252,666. The critical character of the particle size in relevant compositions has been described in the Patent USA 4,442,263, which describes a relevant composition where the crosslinked acrylate has a particular average particle size. In a co-pending patent application, PCT / US 95 06172, a composition is described consisting of a first and a second substrate of grafted acrylate gum which differ from each other in terms of their respective particle sizes and a matrix with which each of the substrates is grafted. The compositional composition of the gum substrate includes acrylate and an unsaturated nitrile monomer. The inventive thermoplastic molding composition according to the present invention consists of: (i) a non-grafted polyalkyl acrylate gum, preferably polybutyl acrylate gum, which may optionally be crosslinked; (ii) a grafted rubber, which may optionally be crosslinked, containing a substrate of polyalkyl acrylate, preferably polybutyl acrylate, and a grafted phase therein (here, grafted phase), wherein the substrate may be homopolymeric or copolymeric and where the grafted phase contains poly (aromatic co-nitrile vinyl), preferably styrene-acrylonitrile (EAN), and (iii) a non-grafted poly (aromatic vinyl aromatic), preferably styrene-acrylonitrile (EAN), having a number average molecular weight of approximately 20,000 to 100,000, preferably 30,000 to 70,000 g / mol. The composition containing approximately 15 to 35, preferably 20 to 30%, by weight of polyalkyl acrylate gum having a weight average particle size of about 0.02 to 1 microns and where the weight ratio between (a) and the total of (a) + (b) is from 0.1 to 0.5, preferably from 0.15 to 0.45, is characterized by having better physical and mechanical properties. The non-grafted polyalkyl acrylate gum, which may optionally be cross-linked, is exemplified by C 1 -C 18 alkyl acrylate monomers and alkyl methacrylate. preferably C2-C8 alkyl acrylate and C1-C4 alkyl methacrylate. more preferred are poly (n-butyl acrylate), poly (ethyl acrylate) and poly (2-ethyl hexylacrylate). Optionally, the gum may contain small amounts, approximately 1 to 20% by weight of the amount of acrylate monomer, of additional monomers such as styrene, (meth) acrylonitrile, methyl methacrylate, (meth) acrylic acid, vinylidene chloride, vinyltoluene or other ethylenically unsaturated comonomers which are copolymerizable with the acrylate monomer. Crosslinking as an eventual feature of the gum used in the present context refers to its substantial insolubility in solvents such as tetrahydrofuran, methyl ethyl ketone, cyclohexanone or acetone. The degree of crosslinking imparted to the gum is that resulting from incorporation into the substrate of about 0.1 to 2.0 parts by weight (pep) of crosslinking agent per one hundred parts by weight of gum (pepg); preferably, the crosslinking agent is present in an amount of 0.4 to 1.4 pg. The crosslinking of the copolymer substrate is achieved during the polymerization of the gum including in the reaction, as the crosslinking agent, a di- or polyfunctional ethylenically unsaturated monomer. Suitable cross-linking agents include divinylbenzene, trimethylolpropane triacrylate, allyl methacrylate, diallyl fumarate, diallyl maleate, 1,3-butylene dimethacrylate, diethylene glycol dimethacrylate, ethylene dimethacrylate, glycol, trimethylolpropane trimethacrylate, methylene bisacrylamide, diethylene glycol diacrylate, ethylene glycol diacrylate, divinyl ether, diallyl phthalate, divinyl sulfone, divinyl sorbitol, triethylene glycol dimethacrylate, trimethylene glycol diacrylate, butylene glycol diacrylate, octylene glycol diacrylate, trimethylolpropane triacrylate , pentaerythritol tetraacrylate ester, ethylidene norbornene, vinylnorbornene, diallyl phosphonate, triallyl cyanurate and triallyl isocyanurate. The preferred crosslinking agent is diallyl maleate (MDA). The non-grafted polyalkyl acrylate gum has a weight average particle size of 0.02 to 1 microns, preferably 0.05 to 0.3 microns. The grafted rubber, which may optionally be crosslinked, contains a polyalkyl acrylate substrate and a grafted phase thereon (here, grafted phase). The substrate may be homopolymer or copolymer and the grafted phase consist of poly (aromatic vinyl co-nitrile), preferably styrene-acryl-nitrile (EAN). The substrate is identical in all the senses to (i) above and is, as (i), eventually cross-linked. The grafted phase which is optionally cross-linked consists of poly (vinyl aromatic co-nitrile), preferably a styrene-acrylonitrile copolymer (EAN). The grafted phase contains approximately 20 to 40 percent of the nitrile copolymer (acrylonitrile or AN) and 80 to 60 percent of the aromatic vinyl comonomer (styrene or E). The relative amounts are from 25 to 35 percent of the first and 65 to 75 percent of the second, the percentages relating to the weight of the grafted phase. Optionally, the grafted phase may include minor amounts, less than 20 weight percent, relative to the weight of this phase, of at least one member selected from the group of additional monomers such as substituted chlorobenzene, styrene (t-butylstyrene) , α-methylstyrene), ethylenically unsaturated compounds (methyl methacrylate, alkyl acrylate, vinylidene chloride, maleic anhydride, N-substituted maleimide), ethylene, propylene and isobutylene. The molecular weight of the grafted phase can be eventually controlled by the use of conventional chain transfer agents. Suitable chain transfer agents include tert-dodecyl mercaptan, n-dodecyl mercaptan, terpenes, terpine-lobes and chlorinated hydrocarbons. The grafted phase may optionally be crosslinked. Cross-linking is achieved by means similar to those discussed above with respect to the substrate. The amount of crosslinking agent incorporated in the grafted phase is from about 0.05 to 0.5, preferably 0.1 to 0.3, pg of grafted phase. The preferred composition of the grafted phase is an EAN copolymer containing 28 percent AN and 72 percent styrene. Cross-linking can be achieved by introduction of DAM. The ratio between the amounts of grafted phase to substrate in component (ii) is in the range of about 25 to 150 pep of grafted phase per 100 pb of substrate. The grafted copolymer gum has a weight average particle size of 0.02 to 1 micron, preferably 0.05 to 0.3 micron. The grafted copolymer gum of the present invention is prepared by any of the methods well known to those skilled in the art. Preferably, these are prepared by polymerizing the styrene and acrylonitrile monomers in the presence of the gum, by emulsion polymerization methods, by mass in suspension or in mass. At least a portion of the monomers is chemically combined or grafted onto the gum substrate and a part forms ungrafted matrix.

A portion of the vinyl aromatic and unsaturated nitrile monomers polymerized in the presence of the gum substrate used to prepare the graft copolymer gum of the present invention will not be grafted to the gum substrate, but will be present as an ungrafted polymer, such as polystyrene-acrylonitrile (EAN). The amount of said non-grafted EAN polymer depends on the weight ratio of the monomers to the rubber, on the nature of the rubber and on the polymerization conditions. This ungrafted portion, preferably EAN, has a number average molecular weight of from about 20,000 to 100,000, preferably 25,000 to 70,000, g / mol. Component (iii) of the composition of the invention is a non-crosslinked and non-grafted poly (aromatic vinyl-co-nitrile), preferably styrene-acrylonitrile. This component is characterized by containing approximately 20 to 40 percent structural units derived from a nitrile comonomer, preferably acrylonitrile, and 80 to 60 percent aromatic vinyl comonomer, preferably styrene; the preferred relative amounts are from 25 to 35 percent of the nitrile comonomer and 65 to 75 percent of the aromatic vinyl comonomer, the percentages being relative to the weight of the poly (vinyl aromatic-co-nitrile) grafted. Optionally, this phase may include minor amounts, less than 20 weight percent relative to the weight of this phase, of additional monomers such as substituted styrene (t-butylstyrene, chlorobenzene, α-methylstyrene) or ethylenically unsaturated compounds, such as methyl methacrylate, alkyl acrylate, vinylidene chloride, ethylene, propylene, isobutylene, maleic anhydride, N-substituted maleimide or mixtures of any of the foregoing. The preferred composition of the non-crosslinked and ungrafted component (iii) contains 32 percent NA and 68 percent styrene. The copolymer is also characterized as having a number average molecular weight of from about 20,000 to 100,000, preferably 30,000 to 7,000 g / mol. The components included in the composition of the invention are conventional and the preparation of each of them has been described in the art; see, for example, US Pat. 3,944,631 and the documents cited therein. Additives, such as light stabilizers, including UV, and thermal, as well as antioxidants, fillers, pigments and dyes in the composition of the invention may be included for their utility recognized in the art.

The processing of the compositions of the invention is carried out in conventional equipment and follows conventional means. In a preferred embodiment of the invention, the substrate of the acrylate copolymer rubber is in the form of particles having a weight average particle size of from about 0.02 to about 1 miter, preferably from about 0.05 to 0.3 microns. The grafted phase is prepared by copolymerizing a vinyl aromatic monomer with an unsaturated nitrile in the presence of the gum substrate to obtain a graft rubber substrate with a grafted phase of poly (vinyl aromatic-co-nitrile). In the grafting process, the preferred vinyl aromatic monomers are styrene, α-methylstyrene and the like. The preferred unsaturated nitrile monomers are acrylonitrile and methacrylonitrile. The relative amounts of the graft monomers used are from 5 to 40% by weight of nitrile monomer and 95 to 60% by weight of vinyl aromatic monomer based on the total weight of unsaturated nitrile and vinyl aromatic monomers used in the grafting procedure. The molecular weight of the polymer produced can be regulated through the addition of commonly used chain transfer agents, such as mercaptans, haloalkanes and terpenes and terpinolens. These can be used in an amount of 0 to 5% in relation to the weight of the grafted phase. A preferred chain transfer agent for this purpose is tert-dodecyl mercaptan. The amount of total graft monomers employed is in the range of 25 to 200 pepg. Following is a description of the preparation of the compositions of the present invention which are based on butyl acrylate-acrylonitrile copolymer rubber. All parts and percentages are by weight, unless otherwise indicated. Steps I, II and III describe the preparation of butyl acrylate polymer, the preparation of a copolymer of grafted butyl acrylate and the recovery of the polymers prepared in steps I and II. Stage I. Preparation of the gum substrate A reaction vessel equipped with a stirrer and a temperature control system is added: Initial charge (parts) Composition 156.1 water 0.2 surfactant 0.1 buffer These were heated with stirring at a temperature of about 65 ° C under a purge of nitrogen. Next, a delayed charge was introduced into the reactor: Delayed charge (parts) Composition (a) 0.4 initiator (b) 1.0 surfactant (c) 99.4 butyl acrylate monomer (d) 0.6 maleate of diallyl (cross-linking agent) (e) 0.4 surfactant The fillers (c) to (e) above were metered into the reactor over a period of 4 hours. The polymerization temperature was maintained at 65 ° C and, after completion, the reactor was cooled to room temperature. The resulting latex had a solids content of about 38% and a gum particle size of 0.13 microns. Stage II. Preparation of the grafted gum To a reaction vessel equipped with a stirrer and a temperature control system are added 277 parts of the rubber latex prepared in step I above. The latex is then heated with stirring and under a purge of nitrogen at a temperature of 70 ° C. After heating, the following is charged into the reactor: Charge (parts) Composition (a) 0.22 initiator (b) 0.04 buffer solution (c) 1.00 surfactant (d) 35.00 styrene monomer (e) 15.00 acrylonitrile monomer (f) 0.12 chain transfer agent (tert-dodecyl mercaptan) The components are charged to the reactor over a period of 3 hours, while maintaining the temperature at 70 ° C. The reaction mixture was maintained at 70 ° C for another period of 0.5 hours to achieve complete conversion. The resulting latex had a solids content of 44.5%. Stage III. Recovery of the grafted gum and mixtures thereof with non-grafted rubber Mixtures of predetermined ratios of grafted rubber latex, non-grafted rubber latex and an EAN copolymer latex were made, such that the rubber content in the solids of latex is 55%. Each of the latex mixtures was dosed in a coagulant solution to the 2%, under stirring at 95 ° C, to form shredded particles suspended in the solution. The crumb suspension was then filtered under vacuum and the resulting crumb cake was washed with fresh water and again filtered under vacuum. The wet cake was then washed and dehydrated in an oven with hot air circulation at 70 ° C to obtain less than 1% water. PREPARATION OF SAMPLES In the following examples, the following formulation was used: Parts Component 45.5 non-grafted polybutyl acrylate acrylate gum and grafted ASA (EAN grafted with butyl acrylate) 54.5 EAN 0.6 stabilizer 0.5 wax (lubricant) The above melted ingredients were combined using a double-screw extruder (melting temperature of about 200 ° C), followed by pelleting. The total rubber content of the resulting compositions is 25% by weight based on the total weight of the composition.

The pellets were dried in an oven with circulating hot air at a temperature of 75 ° C for about 16 hours and then cast in an 80 ton Engel molding machine. The molding condition was: stock temperature 250 ° C, molding temperature 66 ° C, injection speed = 2 seconds propeller speed 35 rpm, back pressure 8.2 kg / cm2. A single-inch Killion single-screw extruder was used to make extruded strips at various melting temperatures (360 ° F, 400 ° F and 450 ° F) and take-off speeds (0.4, 2.3, 4.0, 6.5 and 8.0 cm / second). The dimension of the extruded strips is 14 cm wide by 0.3 cm thick. All specimens were conditioned at 23 ° C and 50% relative humidity for at least 48 hours before the physical examination. Test methods Impact of inverted dart - was determined according to ASTM D3763. The thickness of the sample was 0.26 cm, the diameter of the ring was 3.2 cm and the tests were carried out at room temperature; the results are expressed in Julius Izod Resilience (J / m) - was determined according to ASTM D256. The tests were carried out at room temperature and the results are expressed in Joules / meter. The samples measured 6.35 cm x 1.27 cm x indicated thickness. The test samples were ground with a 0.25 mm radius notch at the midpoint to a remaining height of 10.2 mm. Gloss - was measured at room temperature according to the procedure indicated in ASTM D523 using a Gardener gloss meter with an angle of 60 ° or 20 ° on molded plates (dimension 10.2 cm x 7.6 cm x 0.32 cm) or extruded strips. Traction properties - The tests were performed at room temperature using an Instron universal machine with crosshead speed of 5 mm / minute according to ASTM D-638. Type I traction bars were used. Viscosity (Pascals, second) - The pellets were dried in a vacuum oven at a temperature of 70 ° C for approximately 16 hours before the test. A capillary extrusion rheometer was used to evaluate the viscosity at 260 ° C at various cutting speeds. The dimension of the extrusion die is 50.8 mm in length (L), 1.27 mm in diameter (D), L / D = 40, and an entry angle of 90 °. The tests were carried out according to the indicated procedure in ASTM D3835. The results are expressed in pasca-les-seconds (Pa-s). Experimental: The compositions were prepared by mixing non-grafted butyl acrylate (AB) with a mixture of AB grafted with EAN (ASA) and with free EAN. The following were used in the preparation of the compositions described below: (i) ungrafted AB was introduced into the mixture as a mixture of 45 pbw of free EAN and 55 pbw of a copolymer of butyl acrylate and AN (6% by weight of AN). The free EAN in the mixture contained 26 pep of NA and had a molecular weight of Mn = 48 kg / mol, Mp = 157 kg / mol. The average particle size of the gum was about 0.15 microns; (ii) a rubber component contained 55 pbw of a copolymer of butyl acrylate-AN (6% by weight of AN) and free EAN, with a gel content of approximately 75%. The AN content of the grafted EAN phase is approximately 28 percent by weight; the content in AN in the free EAN was 26 percent by weight. The molecular weight of the free EAN was Mn = 48 kg / mol, Mp = 157 kg / mol. The average particle size of the gum was about 0.15 microns; (iii) the free EAN indicated in the following table is the total of the free EAN introduced together with (i) and (ii) above and EAN that contains 32% of AN; Mn = 54 kg / mol, Mp = 118 kg / mol. All the compositions contained conventional additives used for their known utility: 0.6 parts by weight of resin (ppcr) of antioxidants and 0.5 ppcr of a lubricant, none of which being critical to the invention. The total amount of butyl acrylate gum in the compositions was maintained at a constant 25% relative to the weight of the composition.

Table 1 Example 1 7 8 AB unjustified 0 2.5 5.0 6.3 7.5 8.7 , 0 12, 5 AB grafted 33.8 30.3 27.0 25.3 23.7 22.0 .2 16.9 with free EAN EAN 66.2 67.2 68.0 68.4 68.8 69.3 69.8 70.6 Reason of 0.1 0.2 0.25 0.3 0, 35 0.40 0.50 gum (1) viscosity, @ 500 ° F Pa-sxlO "3 @ 1 s'1 12.9 11.3 9.6 8.2 8.8 7.1 7.5 6.3 @ lOOs "1 0.96 0.93 0.92 0.81 0.81 0.83 0.81 0.73 Brightness, injection molded parts 20 ° 90.5 90.7 90.0 89.8 89.5 88.7 86.9 72.6 600 ° 96.7 97.0 97.1 97.3 97.4 97.5 97.2 93.1 extruded parts 20 ° 28.3 21.3 10.0 6.5 8.3 7.6 .6 5.7 60 ° 87.1 80.2 53.0 41.6 51.1 45.0 36.7 37.2 Elongation to traction Trotting,% 39.6 31.8 64.6 70.9 73.1 65.4 44.0 67.7 Impact resistance Izod, J / m l / 2"(2) 118.4 99.7 179.9 167.0 153.4 146.8 130. 4 112.7 l / 4", 2) 46.8 46.2 153.6 176.0 176.8 165.4 160. 5 112.8 l / 8"(2> 51.6 61.7 140.3 207.2 303.5 412.0 460.0 188.0 Reversed dart, Julios @ room temperature Em 22.7 22.7 21.9 22.0 21.5 21.3 21.3 20.8 Eff 39.0 38.8 38.5 38.3 38.1 37.5 .7 32.5 (1) refers to the ratio between the amount of ungrafted gum and the total amount of gum. (2) refers to the thickness of the test samples. Em refers to energy to the maximum. Ef refers to energy until failure. The results show the critical nature of the content of AB rubber not grafted on the influence on the physical and mechanical properties of the composition. A key finding of the composition of the invention is the dependence of the properties with respect to the indicated rubber ratio at a constant content of gum. Additionally, the brightness values of the extruded parts are indicated, which are significantly lower than the corresponding injection molding articles. In addition, the brightness values of the extruded parts are affected to a large extent by the take-off speed of the table: in general, a higher take-off speed decreases the brightness. The following table summarizes the results, which indicate the dependence of the brightness (60 °) with respect to the takeoff speed at different extrusion temperatures. The composition used in these experiments, the results of which are tabulated below, was the composition designated above as Example 7. Take-off speed Melting temperature (° F) • cm / sec 360 400 450 0.4 18.1 43.3 66.5 2.3 18.9 23.8 62.9 4.0 20 19.2 50.7 6.5 20.1.1 29.8 8.0 20.8 16.1 28.2 Although the invention has been described in detail in the foregoing for illustrative purposes, it is to be understood that said detail has only that purpose and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention, except as may be limited by the claims.

Claims (17)

CLAIMS 1. A thermoplastic molding composition consisting of (a) a polyalkyl acrylate gum not containing grafted phase, (b) a polyalkyl acrylate gum grafted with poly (vinyl aromatic-co-nitrile) and (c) ungrafted poly (aromatic vinyl-co-nitrile), where the weight ratio of (a) to the total of (a) + (b) is from 0.1 to 0.5, the total content in gum is about 15 to 35% relative to the total weight of (a), (b) and (c) and the average particle size of said polyalkyl acrylate gum of (a) and of (b) is about 0.02. to 1 miera. 2. The thermoplastic molding composition of Claim 1, wherein said (a) is butyl acrylate gum. 3. The thermoplastic molding composition of the Claim 1, wherein said (b) is butyl acrylate gum grafted with EAN. 4. The thermoplastic molding composition of Claim 1, wherein said (c) is EAN. 5. A thermoplastic molding composition consisting of (a) butyl acrylate gum not containing grafted phase, (b) butyl acrylate gum grafted with EAN and (c) EAN, where the weight ratio of (a) to the total of (a) + (b) is from 0.1 to 0.5, the total content in gum is about 15 to 35% in relation to the total weight of (a), (b) and (c) and the The average particle size of said polybutyl acrylate gum of (a) and of (b) is about 0.02 to 1 miera. The thermoplastic molding composition of Claim 1, wherein said average particle size of said polyalkyl acrylate gum of (a) and of (b) is about 0.05 to 0.3 microns. The thermoplastic molding composition of Claim 5, wherein said average particle size of said polybutyl acrylate gum of (a) and of (b) is about 0.05 to 0.3 microns. 8. The thermoplastic molding composition of Claim 1, wherein said total rubber content is from about 20 to 30% relative to the total weight from (a), (b) and (c). 9. The thermoplastic molding composition of Claim 5, wherein said total rubber content is from about 20 to 30% relative to the total weight of (a), (b) and (c). 10. A thermoplastic molding composition consisting of (a) butyl acrylate gum not containing grafted phase, (b) butyl acrylate gum grafted with EAN and (c) EAN, where the weight ratio of (a) to total of (a) + (b) is from 0.15 to 0.45, the total content in gum is about 20 to 30% in relation to the total weight of (a), (b) and (c) and the average particle size of said polybutyl acrylate gum of (a) and of (b) is about 0.05 to 0.3 microns. 10. The thermoplastic molding composition of Claim 1, wherein said (a) is a polyalkyl acrylate copolymer and about 1 to 20% of at least one copolymerized ethylenically unsaturated comonomer, the percentage of which is relative to the weight of the copolymer. said (a) 11. The thermoplastic molding composition of the
1. Claim 1, wherein said (a) is a polyalkyl acrylate copolymer and about 1 to 20% of at least one copolymerized monomer selected from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate, acid ( met) acrylic, vinylidene chloride and vinyltoluene, the percentage of which is relative to the weight of said (a). 12. The thermoplastic composition of Claim 1, wherein said (a) is 2-ethylhexyl acrylate. 13. The thermoplastic composition of Claim 1, wherein said (b) contains a copolymeric substrate. 14. The thermoplastic composition of Claim 13, wherein the substrate is a polyalkyl acrylate copolymer and about 1 to 20% of at least one copolymerized ethylenically unsaturated comonomer, the percentage of which is relative to the weight of said (b). The thermoplastic composition of Claim 13, wherein said substrate is a polyalkyl acrylate copolymer and about 1 to 20% of at least one copolymerized monomer selected from the group consisting of styrene, (meth) acrylonitrile, methyl methacrylate , (meth) acrylic acid, vinylidene chloride and vinyltoluene, the percentage of which is relative to the weight of said (b) 16. The thermoplastic composition of Claim 14, wherein said (b) is grafted with EAN. 17. The thermoplastic composition of Claim 13, wherein said (b) is a copolymer grafted with EAN of ethylhexyl acrylate.