MXPA99010559A - Resin composition containing multilayered graft polymer - Google Patents

Abstract

A methacrylic resin composition comprising:a multilayered graft copolymer obtained by polymerizing monomers consisting mainly of an alkyl methacrylate such as methyl methacrylate in the presence of a chain transfer agent to form an innermost layer made of a crosslinked methacrylic polymer, subsequently polymerizing at least one monomer consisting mainly of an alkyl acrylate such as butyl acrylate in the presence of the innermost-layer polymer to form an interlayer, and then polymerizing at least one monomer consisting mainly of an alkyl methacrylate such as methyl methacrylate to form an outermost layer on the interlayer;and a methacrylic resin. The composition is excellent in transparency, appearance, weatherability, gloss, impact resistance, and processability.

Description

COMPOSITION OF RESIN CONTAINING POLYMER IN GRAFT THAT HAS MULTIPLE LAYER STRUCTURE TECHNICAL FIELD The present invention relates to a resin composition comprising a graft copolymer having a multilayer structure and a methacrylic resin and, more particularly, to a methacrylic resin composition having good impact resistance, transparency, appearance, strength in the open, brightness and suceptiblility of treatment, particularly good resistance to impact, transparency and appearance, which is incorporated with a structured graft copolymer with multiple layers. The resin composition of the present invention containing a graft copolymer having a multilayer structure exhibiting excellent strength while maintaining the transparency and appearance of methacrylic resins at a high level and, therefore, is suitable for use in several fields that require such features, for example, as the transparent front panel of automatic vending machines.

PREVIOUS TECHNIQUE Methacrylic resins have excellent transparency, appearance, weather resistance, gloss and processability and, therefore, have been used industrially in large quantities in various fields. However, they have the essential disadvantage of being deficient in impact resistance. In general, the improvement of the resistance to the impact of the methacrylic resins has been made, introducing to the methacrylic resins a structured material with multiple layers, which has a rubber phase, to form a two-phase structure to impart solidity and They have made several proposals based on the same. For example, Japanese Patent Publication Kokoku No. 55-27576 discloses the improvement of the impact strength of methacrylic resins by incorporating methacrylic resins with a polymer having a three layer structure which is prepared by polymerizing a monomeric component containing methacrylate. of methyl as the main component to form the innermost layer, then polymerizing a second monomeric component containing butyl acrylate as the main component in the presence of the innermost layer to form a second layer on the innermost layer and still polymerizing a third polymeric component which contains methyl methacrylate as the main component to form the outermost layer on the second layer. However, it is inevitable that by incorporation deteriorate the beautiful appearance and the peculiar transparency of the methacrylic resins and the improvement of the impact resistance is also insufficient. It is a real circumstance that a resin composition has not been provided, as is required in the market, that exhibits sufficient impact resistance with the preservation of the properties of the methacrylic resins without deteriorating the appearance and transparency and having good thermal stability as required in the molding. It is an object of the present invention to improve the impact strength of methacrylic resins without deteriorating the properties thereof, such as appearance and transparency. A further object of the present invention is to provide a methacrylic resin composition having excellent transparency, appearance and impact resistance as well as good weather resistance, gloss and processability.

BRIEF DESCRIPTION OF THE INVENTION A study has been made about the incorporation of a graft copolymer that has a multiple layer structure, to methacrylic resins, in order to improve the impact resistance without deteriorating the beautiful appearance, the transparency, the weather resistance, the brightness and the processability of methacrylic resins. Thus, it has now been discovered that the above objects can be achieved when, with the polymerization to form the innermost layer of a multilayer methacrylic graft copolymer, the polymerization is carried out in the presence of a chain transfer agent. According to the present invention, there is provided a resin composition comprising (A) from 50 to 5% by weight of a graft copolymer having a multilayer structure and (B) from 50 to 95% by weight of a methacrylic resin, wherein said copolymer is prepared in graft (A): (A-1) by polymerizing a mixture of monomers (X) comprising (a) an alkyl methacrylate having an alkyl group of Ci to C and (b) at least one monomer selected from the group consisting of an alkyl acrylate having an alkyl group of Ci to C12, an aromatic vinyl monomer and other copolymerizable monomers in a ratio (a) / (b) from 40:60 to 100 : 0 by weight and (c) from 0.01 to 10 parts by weight of a polyfunctional monomer per 100 parts by weight of the total of components (a) and (b) in the presence of (d) 0.1 to 2 parts by weight of a chain transfer agent per 100 parts by weight of the total of the components (a) and (b) to give an innermost layer of a polymer interlaced methacrylic (I); (A-2) polymerizing a monomer mixture (Y) comprising (e) an alkyl acrylate having an alkyl group of Ci to C12 and (f) at least one monomer selected from the group consisting of a vinyl monomer aromatic and other copolymerizable monomers in a ratio (e) / (f) from 60:40 to 100: 0 by weight and (g) from 0.1 to 5 parts by weight of a polyfunctional monomer per 100 parts by weight of the total of the components (e) and (f) in the presence of said interlaced methacrylic polymer (I), in a ratio (l) / (Y) of said entangled methacrylic polymer (I) to said monomer mixture (Y) of 10:90 to 60 : 40 in weight, to give a polymer similar to rubber (ii); Y (A-3) polymerizing a monomer component (Z) comprising (h) an alkyl methacrylate having an alkyl group of Ci to C4 and (i) at least one monomer selected from the group consisting of an alkyl acrylate which has an alkyl group of Ci to C-] 2 and other copolymerizable monomers in a ratio (h) / (!) of 60:40 to 100: 0 by weight by weight in the presence of said rubber-like polymer (II), the ratio (l) / (Z) of said rubber-like polymer (II) to said monomer mixture (Z) of 60:40 to 90:10 by weight, to give the multilayer graft copolymer (A).

BEST MODE FOR CARRYING OUT THE INVENTION In the preparation of the graft copolymer having a multilayer structure of the present invention, the entangled methacrylic polymer (I) which constitutes the innermost layer of the graft copolymer is first prepared by polymerizing the monomer mixture (X) comprising (a) an alkyl methacrylate having a group of Ci to C4, (b) at least one monomer selected from the group consisting of an alkyl acrylate having an alkyl group of Ci to C-? 2, a monomer of aromatic vinyl and other copolymerizable monomers; and (c) a polyfunctional monomer, the ratio (a) / (b) being from 40:60 to 100: 0 by weight, to which (d) a chain transfer agent is added in an amount of 0.01 to 2 parts by weight per 100 parts by weight of the total of components (a) and (b). Components (a) and (b) are used in a ratio (a) / (b) from 40:60 to 100: 0 by weight. If the amount of alkyl methacrylate (a) is less than 40 parts by weight based on 100 parts by weight of the total of components (a) and (b), the excellent characteristics possessing the methacrylic resins are not exhibited. The amount of polyfunctional monomer (c) is from 0.01 to 10 parts by weight, preferably from 0.05 to 3 parts, more preferably from 0.2 to 1 part, per 100 parts by weight of the total of components (a) and (b). If the amount of polyfunctional monomer (c) is less than 0.01 part, the transparency of the resin composition obtained is decreased and if the amount is more than 10 parts by weight, the effect of improving the strength of the copolymer is decreased. in graft. The chain transfer agent (d) is used in an amount of 0.01 to 2 parts, preferably 0.1 to 0.8 part, per 100 parts by weight of the total of components (a) and (b). If the amount of the chain transfer agent (d) is more than 2 parts by weight, the effect of improving the strength of the graft copolymer is decreased.

Examples of alkyl metalacrylate (a) having an alkyl group of Ci to C, for example, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and t-butyl methacrylate. These solos or additive mixture can be used. The alkyl methacrylate (a) can be used alone or can be used in combination with the monomer (b) as occasion requires. The monomer (b) is at least one member selected from the group consisting of an alkyl acrylate having a C1-C12 alkyl group, or an aromatic vinyl monomer and another copolymerizable monomer. Examples of alkyl acrylate having a C to C12 alkyl group are, for example, ethyl acrylate, n-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and the like. Examples of aromatic vinyl monomer are, for example, styrene, -methylstyrene, chlorostyrene and other styrene derivatives. Examples of the copolymerizable monomer other than the alkyl methacrylate of the above-mentioned acrylate and aromatic vinyl monomer are, for example, an acrylic or methacrylic acid ester such as hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate. , isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate or hydroxyethyl methacrylate, an unsaturated nitrile compound such as acrylonitrile or methacrylonitrile, a β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid or crotonic acid, vinyl acetate, an olefinic monomer such as ethylene or propylene, a halogenated vinyl monomer such as vinyl chloride, vinylidene chloride or vinylidene chloride , a monomeric monomer such as N-ethylmaleimide, N-propyl-maleimide, N-cyclohexylmaleimide or Non-chlorophenylmaieimide and the like. Either one of the alkyl acrylate, the aromatic vinyl monomer, another copolymerizable monomer alone or in combination of two or more compounds can be used. Acryl acrylates having the alkyl group of C1 to d2 and the vinyl aromatic monomers are preferable as the component (b). In case of using the alkyl acrylates and / or aromatic vinyl monomers, such as component (b), these monomers can be used in combination at most with 40% by weight of other copolymerizable monomers as mentioned above with base in the total weight of component (b). Any of the crosslinking agents or monomers known as the polyfunctional monomer (c) can be used. Preferable examples of the crosslinkable monomer are, for example, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, monoallyl fumarate, butadiene, divinyl benzene and the like. These alone or in an additive mixture thereof can be used. Chain transfer agents generally known as the chain transfer agent (d) can be used in the present invention. Examples of chain transfer agent (d) are, for example, a mercaptan compound such as n-butylmecaptan, n-octyl mercaptan, n-hexadecyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan or t-tetradecyl mercaptan, a thioglycolate. such as a 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate) or pentaerythritol tetrakis (thioglciolate), thiophenol, tetraethylthiuram disulfide, pentaphenylethane, acrolein, methralele, allyl alcohol, carbon tetrachloride, ethylene bromide and Similar. Of these, n-dedecyl mercaptan, a tertiary mercaptan such as t-dodecyl mercaptan and thiophenol are preferred. The chain transfer agents can be used alone or in an additive mixture thereof. An intermediate layer is then formed on the crosslinked metracrylic polymer (I) to give the rubber-like polymer (II). The rubber-like polymer (ll) is prepared by polymerizing a mixture of monomers (Y) comprising (e) an alkyl acrylate having an alkyl group of Ci to C12, (f) at least one monomer selected from the group it consists of an aromatic vinyl monomer and other copolymerizable monomers, and (g) a polyfunctional monomer, the ratio (e) / (f) being from 60:40 to 100: 0 by weight, in the presence of the crosslinked methacrylic polymer (l) . As the alkyl arylate (e) having an alkyl group of d-C12, those explained in relation to component (b) can be used. The alkyl acrylate (e) may be the same as or different from the alkyl acrylate used as the component (b). The alkyl acrylate (e) can be used alone or in combination with the monomer (f). The monomer (f) is at least one member selected from the group consisting of an aromatic vinyl monomer and another copolymerizable monomer. As the aromatic vinyl monomer in component (f), those explained in relation to component (b) can be used. The aromatic vinyl monomer may be the same as or different from the aromatic vinyl monomer used with the component (b). Examples of the copolymerizable monomer other than the above-mentioned alkyl acrylate and aromatic vinyl monomer are, for example, an acrylic or methacrylic benzyl ester such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate. , 2-ethylhexyl methacrylate, octyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate or hydroxyethyl methacrylate, unsaturated nitrile compound such as an acrylonitrile or methacrylonitrile, a, ß-unsaturated carboxylic acid such as acrylic acid or crotonic acid, acetate of vinyl, an olefinic monomer such as ethylene or propylene, a halogenated vinyl monomer such as vinyl chloride, vinylidene chloride or vinylidene fluoride, a maleimide monomer such as N-ethylmaleimide, N-propylmaleimide, N-cyclohexylmaleimide or -chlorophenylmaleimide and the like. They can be used alone or in an additive mixture thereof. The aromatic vinyl monomers are preferable, as the component (f). In case of using the aromatic vinyl monomers as the component (f), these monomers can be used in combination at most with 40% by weight of other copolymerizable monomers as mentioned above based on the total weight of the component (f ).

Also, as the polyfunctional monomer (g), those explained in relation to component (c) can be used. The polyfunctional monomer (g) may be the same or different from the polyfunctional monomer used as the component (c). A chain transfer agent such as mercaptan can be used in the polymerization of monomer mixtures (Y). Components (e) and (f) are used in a ratio (e) / (f) from 60:40 to 100: 0 by weight, preferably from 70:30 to 90:10 by weight. If the amount of alkyl acrylate (e) is less than 60 parts by weight based on 100 parts by weight of the total of components (e) and (f), the effect of improving the impact strength of the graft copolymer obtained and transparency is also decreased. The amount of the polyfunctional monomer (g) is 0.1 to 5 parts by weight, preferably 1 to 3 parts, per 100 parts by weight of the total of components (e) and (f). If the amount of the polyfunctional monomer (g) is 0.1 part, the transparency and impact resistance of the resin composition obtained is decreased, and if the amount is more than 5 parts by weight, the impact resistance is decreased. The entangled methacrylic polymer (I) and the monomer mixture (Y) are used in a ratio (l) / (Y) of 10:90 to 60:40 by weight. If the amount of crosslinked methacrylic polymer (I) is less than 10 parts by weight based on 100 parts by weight of the total weight of the interlaced polymer (I) and the monomer mixture (Y), transparency is decreased. If the amount of crosslinked methacrylic polymer (I) is more than 60 parts by weight, the impact strength tends to decrease. The outermost layer is then formed on the rubber-like polymer (II) to give the graft copolymer (A) having multiple layer structure. The outermost layer is formed by polymerizing the monomer component (Z) comprising (h) an alkyl methacrylate having an alkyl group of Ci to C4 and optionally (i) at least one monomer selected from the group consisting of acrylate of alkyl having an alkyl group of Ci to C12 and other copolymerizable monomers in the presence of the rubber-like polymer (II). As the alkyl methacrylate (h) having an alkyl group of C1 to C, those explained in relation to component (a) can be used. The alkyl methacrylate (h) may be the same as or different from the compound used as the component (a). As the alkyl acrylate having a C1 to C12 alkyl group in component (i), those explained in relation to component (b) can be used. The alkyl acrylate may be the same as or different from the alkyl acrylate used as the component (b). Examples of the copolymerizable monomer other than the above-mentioned acrylate and alkyl methacrylate are, for example, an ester of acrylic or methacrylic acid such as hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate or hydroxyethyl methacrylate, an aromatic vinyl monomer such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene or α-methylstyrene, an unsaturated nitrile compound such as acrylonitrile or methacrylonitrile, an acid α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid or crotonic acid, vinyl acetate, an olefinic monomer such as ethylene or propylene, a halogenated vinyl monomer such as vinyl chloride, vinylidene chloride or vinylidene fluoride, a maleimide monomer such as N-ethylmaleimide, N-propylmaleimide, N-cyclohexylmaleimide or non-chlorophenyl leimida and the like. These alone or in an additive mixture thereof can be used. Alkyl acrylates having an alkyl group of C-i to C12 are preferable as component (i). In case of using alkyl acrylates as component (i), these monomers can be used in combination at most with 40% by weight of other copolymerizable monomers as mentioned above based on the total weight of component (i). The components (h) and (i) are used in a ratio (h) / (i) of 60:40 and 100: 0 by weight. If the amount of the alkyl methacrylate (h) is less than 60 parts by weight based on 100 parts by weight of the total of the components (h) and (i), resistance to impact and transparency are diminished and productivity can also be reduced. The rubber-like polymer (II) and the monomer component (Z) are used in a ratio (ll) / (Z) of 60:40 to 90:10 by weight. If the amount of rubber-like polymer (II) is less than 60 parts by weight based on 100 parts by weight of the total weight of the rubber-like polymer (II) and the monomer component (Z), the transparency is decreased. If the amount of rubber-like polymer (II) is more than 90 parts by weight, the tendency of impact resistance and transparency is decreased. In the formation of the outermost layer, ie in the polymerization of the monomeric component (Z), a polyfunctional monomer (crosslinker monomer) and / or a chain transfer agent such as a mercaptan is used, as occasion requires. The multilayer graft copolymer (A) in the present invention can be prepared in the usual manner by emulsion polymerization using a known emulsifier. In obtaining the multilayer graft copolymer having well-balanced physical properties, it is preferable that the graft copolymer (A) in the obtained latex have an average particle size of from 1,000 to 4,500 A, especially 1,500 a. 4,000 Á. The multi-layer graft copolymer is obtained in the form of a powder, by spray-drying the copolymer latex in a multilayer graft or in a generally known manner by coagulating the latex with the addition of a salt or an acid, thermally treating the coagulated latex and filtering the graft copolymer, followed by washing and drying. If required, an antioxidant or an ultraviolet absorber can be added as is generally used at the time of coagulation. The multi-layer graft copolymer thus obtained has well-balanced properties such as appearance, transparency, weather resistance, gloss and processability, and can be combined with various resins. When combined with a methacrylic resin, a resin composition exhibiting excellent properties such as weathering, gloss and processability can be provided without deteriorating the excellent appearance and transparency peculiar to the methacrylic resin. The methacrylic resins used in the present invention are resins containing at least 50% by weight of units of an alkyl methacrylate having an alkyl group of C-i to C4. The multilayer graft copolymer (A) of the present invention is applicable to resins generally called methacrylics. Representative examples of the methacrylic resin (B) used in the present invention are homo- and copolymers from 50 to 100% by weight of methyl methacrylate and from 50 to 0% by weight of other monomers copolymerizable therewith. The other copolymerizable monomers include, for example, an ester of acrylic or methacrylic acid such as methyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methacrylate octyl, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, an aromatic vinyl monomer such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene or α-methylstyrene, an unsaturated nitrile compound such as acrylonitrile or methacrylonitrile, an α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid or crotonic acid, vinyl acetate, an olefinic monomer such as ethylene or propylene, a halogenated vinyl monomer such as vinyl chloride, vinylidene chloride or vinylidene fluoride, a maleimide monomer such as N-ethylmaleimide, N-propylmeleimide, N-cyclohexylmaleimide or N -o-chlorophenylmaleimide and the like.

These alone or in an additive mixture thereof can be used. The combination ratio of the metracrylic resin (B) and the multilayer graft copolymer (A) varies depending on the uses of the resin composition, but is preferably combined in amounts of 50 to 95% by weight of the mecrylic resin and 50 to 5% by weight of the graft copolymer, the total thereof being 100% by weight. If the amount of the methacrylic resin is less than 50% by weight, the characteristics of the methacrylic resin are lost and if the amount is more than 95% by weight, the impact resistance is not sufficiently improved. The manner of combination for preparing the resin composition of the present invention is not particularly limited and various known methods are applicable such as extrusion mixing and cylinder mixing. The resin composition of the present invention may contain usual additives such as antioxidant, ultraviolet absorber, light stabilizer and others. The present invention is then explained by way of examples, but it is intended that these examples illustrate the invention and should not be interpreted as limiting the scope of the invention. In the following examples, all percentages and parts are by weight unless otherwise indicated.

EXAMPLE 1 Preparation of the multilayer polyurethane copolymer (A) (a) Polymerization of the interlaced metracrylic polymer (innermost layer). A glass reactor was charged with a mixture having the following composition.

Mix part deionized water 220 boric acid 0.3 sodium carbonate 0.03 N-lauroyl sarcosine salt-sodium 0.09 sodium formaldehyde-sulfoxylate 0.09 disodium ethylenediaminetetraacetate 0.006 ferrous sulfate heptahydrate 0.002 After raising the temperature to 80 ° C by stirring in a stream of hydrogen, the reactor was charged at the same time with 25% of a mixture of 0.1 part of t-butyl hydroperoxide (BHPO) with a monomeric component for the further layer. internal compound of 25 parts of methyl methacrylate, 0.1 part of allyl methacrylate and 0.1 part of t-dodecyl mercaptan, and the polymerization is carried out for 45 minutes.

Subsequently, the remaining 75% of the mixture was continuously added to the reactor for 1 hour. After the completion of the addition, the reaction system was maintained at 80 ° C for 2 hours to complete the polymerization. During this period, 0.2 part salt of N-lauroyl sarcosine sodium was added. The polymer particles in the latex obtained from the crosslinked metracrylic polymer of the innermost layer had an average particle size of 1.600 A (measured using light diffusion at a wavelength of 546 nm). The polymerization conversion (amount of polymer produced / amount of charged monomer) was 98%. (b) Polymerization of the rubber-like polymer After adding 0.1 part of potassium persulfate to the interlaced methacrylic polymer latex obtained in (a) which was maintained at 80 ° C in a stream of nitrogen, it was added to the latex continuously for 5 hours a monomer mixture of 41 parts of n-butyl acrylate, 9 parts of styrene and 1 part of nickel methacrylate. During this period, potassium oleate was added three times in an amount of 0.1 part in total. After the conclusion of the addition of the monomer mixture, 0.05 parts of potassium persulfate was further added and the reaction system was maintained for 2 hours to complete the polymerization. The rubber-like polymer that was obtained had an average particle size of 2,300 A and the polymerization conversion was 99%. (c) Polymerization of the outermost layer The obtained rubber-like polymer latex obtained in part (b) was maintained at 80 ° C. After adding 0.02 part of potassium persulfate thereto, a monomer mixture of 24 parts of methyl methacrylate was added to the latex continuously for 1 hour., 1 part n-butyl acrylate and 0.1 part t-dodecyl mercaptan. After the conclusion of the addition of the monomer mixture, the reaction system was still maintained for 1 hour to give an aqueous latex of a copolymer in multi-layer graft. The multilayer graft copolymer in the latex had an average particle size of 2.530 A, and the polymerization conversion was 99%. The multilayer multilayer copolymer latex obtained in salt precipitation for coagulation, heat treatment and drying in a known manner to give a white powder of the multilayer graft copolymer was subjected. The thermal decomposition temperature of the obtained multilayer graft copolymer was measured by differential thermal analysis (ATD) using the TAS-100 Thermal Analysis Station made by Rigaku Denki Kabushiki Kaisha in an air stream of 50 ml / minute under conditions of temperature rise rate of 10 ° C / minute, a-alumina as typical sample and weight of each of the typical samples, and the sample was measured at approximately 5 mg. A point of intersection of the base line of the ATD frame and the maximum slope of a peak was determined, as the starting temperature of thermal decomposition.

The results of the measurement of the thermal decomposition starting temperature as DTA are shown in Table 1.

Preparation of the resin composition The obtained multilayer graft copolymer was mixed with a metracrylic resin (methacrylic resin MG-102 made by ICI Ltd., copolymer of 98% methyl methacrylate and 2% ethyl acrylate) in a ratio of 40:60 in weight. The resulting mixture was incorporated with 0.1% to a phosphorus stabilizer (TNPP) and transformed into pellets using a simple worm extruder, equipped with vent (worm diameter 40 mm, L / D = 28) by kneading and extruding a temperature from 200 to 230 ° C. Pellets obtained at 80 ° C were dried for more than 4 hours and molded by injection at 255 ° C to give plaque samples having a size of 100 × 150 × 3 mm for evaluation of their physical properties. Using the obtained samples, the turbidity was measured at 23 ° C according to JIS K 6714 and the impact strength of Gardner was measured using a weight of 1.7 kg according to ASTM D 3029-GB. The results are shown in table 2.

EXAMPLE 2 A graft copolymer having a multiple layer structure was prepared in the same manner as in Example 1, except that the innermost layer of the interlaced methacrylic polymer was prepared from a monomer component for the innermost layer, composed of 12.5 parts of methyl methacrylate, 10 parts of n-butyl acrylate, 2.5 parts of styrene, 0.1 part of allyl methacrylate and 0.1 part of t-dodecyl mercaptan. The result of the DTA measurement is shown in table 1. Also, a resin composition was prepared by mixing the multilayer graft copolymer obtained with a methacrylic resin in the same manner as in example 1. The results of the turbidity measurement and the Gardner's impact of it.

EXAMPLE 3 A graft copolymer having a multilayer structure was prepared in the same manner as in Example 1, except that 0.13 part of n-dodecyl mercaptan was used in place of t-dodecyl mercaptan in the preparation of the innermost layer of the polymer methacrylic interlaced. The result of the DTA measurement is shown in table 1. Also, a resin composition was prepared by mixing the multilayer graft copolymer obtained with a methacrylic resin in the same manner as in example 1. The results of the turbidity measurement and the Gardner's impact of it.

COMPARATIVE EXAMPLE 1 A graft copolymer having a multiple layer structure was prepared in the same manner as in Example 1, except that t-dodecyl mercaptan was not used in the preparation of the innermost layer of the crosslinked methacrylic polymer. The result of the DTA measurement is shown in table 1. Also, a resin composition was prepared by mixing the multilayer graft copolymer obtained with a methacrylic resin in the same manner as in example 1. The results of the turbidity measurement and the Gardner's impact of it.

COMPARATIVE EXAMPLE 2 A graft copolymer having a multilayer structure was prepared in the same manner as in Example 2, except that t-dodecyl mercaptan was not used in the preparation of the innermost layer of the interlaced methacrylic polymer. The result of the DTA measurement is shown in table 1. Also, a resin composition was prepared by mixing the co-polymer in multi-layer graft obtained with a methacrylic resin in the same manner as in example 1. The results of the turbid.ez measurement and the Gardner's impact resistance of it.

COMPARATIVE EXAMPLE 3 A graft copolymer having a multilayer structure was prepared in the same manner as in Example 2except that the preparation of the innermost layer of the interlaced methacrylic polymer, t-dodecyl mercaptan, was used in an amount of 0.6 part instead of 0.1 part. The result of the DTA measurement is shown in table 1. Also, a resin composition was prepared by mixing the multilayer graft copolymer obtained with a methacrylic resin in the same manner as in Example 1. The results of the turbidity measurement and the Gardner's impact of it.

CONTROL Test examples were prepared in the same manner as in Example 1 from the methacrylic resin used in Example 1 without combining it with any graft copolymer. The measurement results of Gardner's turbidity and impact resistance are shown in Table 2. In table 1, the abbreviations denote the following compounds.

MM: methyl methacrylate BA: butyl acrylate St: styrene AIMA: allyl methacrylate t-DM: t-dodecyl mercaptan n-DM: n-docecyl mercaptan KPS: potassium persulfate BHPO: t-butyl hydropere TABLE 1 Ex. Com. Ex. Com. Ex. Com Ej- 1 Ex. 2 Ex. 3 1 2 3 Multilayer graft copolymer Monomer of the innermost component layer (part) MMA 25 12.5 25 25 12.5 25 BA 10 - 10 - St 2.5 - 2.5 - AIMA 0.1 0.1 0.1 0.1 0.1 0.1 t-DM 0.1 0.1 - - 0.6 n-DM 0.1 initiator BHPO BHPO BHPO BHPO BHPO BHPO Monomer of the intermediate layer component (part) Ul BA 41 41 41 41 41 41 St 9 9 9 9 9 9 10 AIMA 1 1 1 1 1 1 K initiator KPS KPS KPS KPS KPS PS Monomer of the outermost component layer (part) MMA 24 24 24 24 24 24 BA 1 1 1 1 1 1 t-DM 0.1 0.1 0.1 0.1 0.1 0.1 KPS KPS initiator KPS KPS KPS KPS Evaluation result 240 250 235 220 230 250 15 ATD (° C) TABLE 2 Ex. Com. Ex. Com. Ex. Com. Ex. 1 Ej- 2 Ex. 3 Control * 1 2 3 Turdibez (%) 1.3 1.4 1.3 1.3 1.4 1.4 0.6 Gardner impact resistance (kg cm) 80 90 80 60 70 40 5"Methacrylic resin alone K5 s.

INDUSTRIAL APPLICABILITY The methacrylic resin compositions containing the multilayer graft copolymer according to the present invention exhibit excellent impact resistance while maintaining excellent transparency, appearance, weather resistance and gloss originally possessed by the methacrylic resins.

Claims (3)

NOVELTY OF THE INVENTION CLAIMS

1. - A resin composition comprising (A) from 50 to 5% by weight of a graft copolymer having a multilayer structure and (B) from 50 to 95% by weight of a methacrylic resin, wherein said graft copolymer (A): (A-1) polymerizing a monomer mixture (X) comprising (a) an alkyl methacrylate having an alkyl group of Ci to C and (b) at least one monomer selected from the group which consists of an alkyl acrylate having an alkyl group of Ci to C-12, an aromatic vinyl monomer and other copolymerizable monomers in a ratio (a) / (b) from 40:60 to 100: 0 by weight and ( c) from 0.01 to 10 parts by weight of a polyfunctional monomer per 100 parts by weight of the total of components (a) and (b), in the presence of (d) 0.01 to 2 parts by weight of a chain transfer agent per 100 parts by weight of the total of the components (a) and (b) to give an innermost layer of an entangled methacrylic polymer (I); (A-2) polymerizing a mixture of monomers (Y) comprising (e) an alkyl acrylate having an alkyl group of Ci to C12 and (f) at least one monomer selected from the group consisting of aromatic vinyl monomer and other copolymerizable monomers in a ratio (e) / (f) from 60:40 to 100: 0 by weight and (g) from 0.1 to 5 parts by weight of a polyfunctional monomer per 100 parts by weight of the total components ( a) and (b), in the presence of said entangled methacrylic polymer (I), the ratio (l) / (Y) of said entangled methacrylic polymer (I) being said monomer mixture (Y) of 10:20 to 60 : 40 in weight, to give a polymer similar to rubber (II); and (A-3) polymerizing a monomer component (Z) comprising (h) an alkyl methacrylate having an alkyl group of Ci to C and (i) at least one monomer selected from the group consisting of an "acrylate" of alkyl having an alkyl group of Ci to C-12 and other copolymerizable monomers in a ratio (h) / (i) of 60:40 to 100: 0 by weight, in the presence of said rubber-like polymer (II), the ratio (ll) / (Z) of said rubber-like polymer (II) being to said monomer mixture (Z) of 60:40 to 90:10 by weight, to give the multilayer graft copolymer (A) .

2. - The composition according to claim 1, further characterized in that said chain transfer agent is a mercaptan compound.

3. - The composition according to claim 2, further characterized in that said mercaptan compound is a tertiary mercaptan compound.