JPH0745610B2 - Thermoplastic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition having high impact resistance and good moldability.

[0002]

2. Description of the Related Art Thermoplastic resins, particularly vinyl chloride resins (hereinafter abbreviated as PVC) are widely used as general-purpose resins, but their mechanical properties are not always satisfactory. That is, PVC is inferior in impact strength, especially impact strength with a notch, and various methods have been proposed for the purpose of improving such impact strength.

The most effective method among these proposals is a method in which a graft copolymer obtained by graft-polymerizing a monomer such as styrene, methyl methacrylate and acrylonitrile to a conjugated diene elastic body is mixed with PVC. Such a graft copolymer has already been marketed as an impact resistance modifier for PVC, and has greatly contributed to the expansion of applications of PVC molded articles.

By the way, in profile extrusion applications, there is a demand for a composition having a high impact strength even when molded under the condition that it is extremely slippery and does not work well.
The hitherto proposed impact modifiers are not sufficiently satisfactory. That is, a multilayer graft copolymer obtained by graft-polymerizing a resin component having good compatibility with PVC on an elastic body as a conventional impact modifier is processed at a high temperature or when a relatively small amount of a lubricant is used. While the multi-layered graft copolymer is uniformly dispersed in PVC and shows good impact resistance, the multi-layered graft copolymer does not aggregate in PVC when it is processed at low temperature or when a large amount of lubricant is used. However, there is almost no effect of improving impact resistance.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have conducted extensive studies based on the idea that it is most effective to improve the impact resistance by uniformly dispersing such a multilayer graft copolymer in PVC. The outermost layer has a glass transition temperature (hereinafter abbreviated as Tg) of 0 ° C. or lower than that of the multi-layered graft copolymer, which is PVC.
When blending and molding, the state of dispersion is good even under high kneading conditions, and even when the kneading is low and the shear stress is low, the multi-layer graft copolymer melts rapidly and gels. And the dispersion state is extremely good,
We filed a patent application earlier on the finding that it can exhibit high impact strength under a wide range of molding conditions and is effective as an impact resistance modifier for thermoplastic resins. A mixture of a specific amount of a specific copolymer containing a specific unsaturated acid monomer as an essential component in the coalescence acts as a better impact modifier, and also has good processability and surface gloss. The present invention has been achieved by finding that an excellent molded product can be obtained.

[0006]

[Problems to be Solved by the Invention] Polybutadiene or butadiene containing 100 parts by weight of a thermoplastic resin and 0 to 5% by weight of a cross-linking agent, and 50% by weight or more of other vinyl compounds copolymerizable therewith and 50% by weight or less of other vinyl compounds. A multi-layer graft copolymer in which at least two graft layers are graft-polymerized to a butadiene-based elastic body (A) made of a copolymer, and the graft layer is an acrylic acid alkyl ester, a methacrylic acid alkyl ester, or an aromatic vinyl. Compound, a vinyl cyanide compound, and a monomer selected from the group of monomers consisting of budadiene. Each graft layer contains 0 to 5% by weight of a crosslinking agent with respect to each layer, and constitutes the outermost layer (C). The glass transition temperature of the polymer to be used is 0 ° C or lower, and the glass transition temperature of the polymer constituting the second layer (B) from the outermost layer (C) is 60 ° C or higher. A copolymer obtained by copolymerizing 100 parts by weight of the graft copolymer (1) with 3 to 30% by weight of an unsaturated acid monomer and 97 to 70% by weight of a vinyl monomer copolymerizable therewith ( 2) A thermoplastic resin composition comprising 3 to 50 parts by weight of an impact resistance improver prepared by blending 0.1 to 20 parts by weight and having good impact resistance and moldability.

The impact modifier of the present invention comprises a blend of the above-mentioned multilayer graft copolymer (1) and copolymer (2), and the above-mentioned multilayer graft copolymer has at least three stages. It is essential to have a multi-layer structure of three or more layers obtained by polymerizing over the course of course. Of course, there is no problem even if the graft layer has three layers or four layers, and until the Tg of the polymer constituting the outermost layer continues Any polymer structure having a Tg of 0 ° C. or less and a polymer forming the second layer counting from the outermost layer of 60 ° C. or more may be used. Even if the monomer mixture is polymerized in multiple stages depending on the purpose, the impact resistance improving effect is similarly shown.

The monomer group constituting the multi-layer graft copolymer (1), which is one component of the impact modifier of the present invention, includes alkyl acrylate, methacrylic acid alkyl ester, aromatic vinyl compounds and vinyl cyan. It is composed of a compound and butadiene.

As the acrylic acid alkyl ester, those having an alkyl group having 2 to 10 carbon atoms are preferable. For example, acrylic acid ester, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, acrylic acid. Octyl and 2-ethyl acrylate-
Hexyl and the like can be mentioned.

As the methacrylic acid alkyl ester,
An alkyl group having 1 to 4 carbon atoms is preferable, and examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate. To be Methyl methacrylate is particularly preferable in consideration of compatibility with PVC.

Examples of the aromatic vinyl compound include styrene, α-substituted styrene, nucleus-substituted styrene and derivatives thereof such as α-methylstyrene, chlorostyrene and vinyltoluene.

Further, examples of the vinyl cyan compound include acrylonitrile and methacrylonitrile.

Furthermore, examples of butadiene include 1,2-butadiene and 1,3-butadiene.

The component of the outermost layer (C) constituting the multilayer graft copolymer (1) is selected from the above monomer group so that the Tg of the outermost layer (C) itself is 0 ° C. or lower. The composition ratio of the monomer in the outermost layer (C) is 0 to 100% by weight of alkyl acrylate, 0 to 40% by weight of methacrylic acid alkyl ester, 0 to 40% by weight of aromatic vinyl compound, and 0 of vinyl cyanide compound. It can be used in the range of ˜40 wt% and butadiene of 0-100 wt%. When the Tg of the outermost layer (C) itself exceeds 0 ° C., it is difficult to obtain the desired impact resistance improving effect. In addition, acrylic acid alkyl ester is preferable to butadiene in that atmospheric polymerization is possible.

The proportion of the outermost layer (C) in the total amount of the multi-layer graft copolymer is preferably 10 to 60% by weight, and if it is less than 10% by weight, the impact resistance improving effect is small, and 6
A proportion of more than 0% by weight is not preferable because the moldability when blending with PVC and molding becomes poor.

The components of the second layer (B) counted from the outermost layer (C) are selected from the above monomer group so that the Tg of the layer (B) itself is 60 ° C. or higher. The composition ratio of the monomer in the layer (B) is 0 to 100% by weight of methacrylic acid alkyl ester, 0 to 100% by weight of aromatic vinyl compound, 0 to 100% by weight of vinyl cyan compound, and 0 to 20% of acrylic acid alkyl ester. It can be used in the range of weight%. When the Tg of the layer (B) itself is less than 60 ° C., the multi-layered graft polymer particles are likely to aggregate and the impact resistance is poor. Layer (B)
When blending with PVC, alkyl methacrylic acid ester is preferable, and methyl methacrylate is particularly preferable. An aromatic vinyl compound improves its fluidity during blend molding with PVC, but when used in a large amount, its compatibility deteriorates and its impact resistance decreases. A vinyl cyan compound is preferable because it promotes gelation at the time of blending with PVC, but when used in a large amount, it tends to be colored during molding and the workability deteriorates.

The proportion of the layer (B) in the total amount of the multilayer graft copolymer is preferably 20 to 60% by weight, and 20% by weight.
If it is less than the above range, the molding processability at the time of blending with PVC and molding is inferior, which is not preferable. On the other hand, if the proportion exceeds 60% by weight, the amount of the elastic material component in the whole multilayer graft copolymer is reduced, and the impact resistance improving effect is small, which is not preferable.

The butadiene-based elastic material (A) contains a rubber component which is a base material of the multi-layered graft copolymer, and the rubber component is 50% by weight or more of polybutadiene or butadiene and 50% by weight of another vinyl compound copolymerizable therewith. It is the following copolymer. Examples of the other copolymerizable vinyl compound include styrene, acrylonitrile, acrylic acid alkyl ester, and methacrylic acid alkyl ester.

The proportion of the budadiene-based elastic material (A) in the total amount of the multilayer graft copolymer is preferably 10 to 60% by weight, and if it is less than 10% by weight, the impact resistance improving effect is small. Further, if the proportion exceeds 60% by weight, not only the solidification of the emulsion polymer latex becomes difficult, but also the molding processability at the time of blending with PVC and molding is inferior, which is not preferable.

The cross-linking agent in the present invention not only facilitates the graft cross-linking in producing the above-mentioned multilayer graft copolymer, but also greatly improves the coagulability of the emulsion polymer latex. As the cross-linking agent, divinylbenzene, diacrylic acid ester or dimethacrylic acid ester which is an ester of acrylic acid or methacrylic acid and a polyhydric alcohol, or triallyl cyanurate, triallyl isocyanurate, allyl acrylate, allyl methacrylate, itacone Examples thereof include diallyl acid and diallyl phthalate. From the viewpoint of graft crossing property, a cross-linking agent having an allyl group is preferable.

The proportion of the crosslinking agent in each layer is 0 to 5% by weight. When it is used in an amount of more than 5% by weight, the elastic properties of the butadiene-based elastic body (A) or layer (C) constituting the elastic body layer are too impaired. The resin layer (B) is PVC
Since the compatibility with and deteriorates, the effect of improving impact resistance is reduced, which is not preferable. The proportion of the cross-linking agent in each layer is 0.1 to 3% by weight in consideration of the coagulability of the emulsion polymer latex at the time of producing the multi-layer graft copolymer and the impact resistance improving effect of the obtained multi-layer graft copolymer. Is preferred.

The multi-layer graft copolymer in the present invention is usually preferably produced by emulsion polymerization of a monomer selected from the above monomer group or a mixture thereof in the presence of the butadiene type elastic body (A) latex. .

Examples of the emulsifier include anionic surfactants such as fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkyl phosphate ester salts, dialkyl sulfosuccinates, polyoxyethylene alkyl ethers and polyoxyethylene. Nonionic surfactants such as fatty acid esters, sorbitan fatty acid esters, and glycerin fatty acid esters, and cationic surfactants such as alkylamine salts can be used. These surfactants can be used alone or in combination.

As the polymerization initiator, an ordinary inorganic initiator such as a persulfate, an organic peroxide, an azo compound or the like may be used alone, or the above compound and a sulfite, a hydrogen sulfite or a thiosulfate may be used. , A first metal salt, sodium formaldehyde sulfoxylate, etc. may be combined and used as a redox initiator. Preferred persulfates as the initiator are sodium persulfate, potassium persulfate, ammonium persulfate and the like, and the organic peroxide is t
-Butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like.

A chain transfer agent may be used to control the molecular weight of the polymer, and an alkylmercaptan having 5 to 20 carbon atoms can be used.

Polymerization is carried out at a temperature above the decomposition temperature of the initiator,
Under ordinary emulsion polymerization conditions, at least the outermost layer (C), the second outermost layer (C) to the second layer (B), and the butadiene-based elastic body (A) can be formed so as to have the structure as described above. At this time, the polymerization in each of the steps can be carried out while adding the whole amount of each monomer or a mixture of the monomers at once, or continuously adding the whole amount or a part thereof. The monomer or the mixture of monomers may be polymerized in one stage or multiple stages.

The copolymer (2), which is another component of the impact modifier of the present invention, comprises 3 to 30% by weight of an unsaturated acid monomer and 97 to 90% of a vinyl monomer copolymerizable therewith. It is obtained by copolymerizing 70% by weight, and the emulsion polymerization method is preferable as its production method.

The unsaturated acid monomer is an acid group-containing monomer such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid, maleic anhydride or butenetricarboxylic acid. The amount of unsaturated acid monomer in the copolymer (2) is 3% by weight.
If the amount is less than the range, it is not preferable because it is blended with the multilayer graft copolymer (1) and used as an impact resistance modifier because the impact resistance improving effect is small. Further, if it exceeds 30% by weight, the latex obtained by emulsion polymerization is not stable, and the latex stability is deteriorated when blended with the latex of the above-mentioned multilayer graft copolymer (1), and further blended with PVC. It is not preferable because the workability when doing so becomes worse.

Examples of the vinyl monomer copolymerizable with the unsaturated monomer include acrylic acid alkyl ester, methacrylic acid alkyl ester, aromatic vinyl compound, vinyl cyan compound and budadiene. The body groups can be used alone or as a mixture.

When the copolymer (2) is produced by the emulsion polymerization method, the same emulsifiers, polymerization initiators, chain transfer agents, etc. that can be used in the production of the multilayer graft copolymer (1) are used. Can be used, and can be copolymerized in the same manner as in the production of the multilayer graft copolymer (1).

The impact modifier of the present invention is a blend of the multi-layer graft copolymer (1) and the copolymer (2) obtained as described above, and the blending ratio thereof is the multi-layer graft copolymer (1). ) Copolymer (2) is 0.1-2 with respect to 100 parts by weight.
0 parts by weight. If the blending amount of the copolymer (2) is less than 0.1 parts by weight, the impact resistance improving effect is small, and if it exceeds 20 parts by weight, the latex becomes unstable when both copolymers are latex blended. Therefore, both are not preferable.

In carrying out the present invention, the multi-layer graft copolymer (1) and the copolymer (2) are blended by mixing the respective latexes in the above-mentioned mixing ratio in terms of solid content, and the blended latex is usually used as a salt. It may be collected by powdering or acid precipitation and washed with water after filtration, or may be collected in powder form by spray drying or freeze-drying. It can also be recovered by the method described in JP-A-57-187322. Further, a method of blending individual powders of the multi-layered graft copolymer (1) and the copolymer (2) later may be used. The method obtained by the above-mentioned latex blend is particularly preferable.

When the impact modifier of the present invention is blended with various thermoplastic resins, it imparts high impact properties and good processability to the thermoplastic resin, and the surface gloss of the molded article is good. It is what

The proportion of the impact modifier of the present invention incorporated into the thermoplastic resin is 3 to 100 parts by weight of the thermoplastic resin.
It is 50 parts by weight. If the blending ratio is less than 3 parts by weight, the impact resistance improving effect is small, and if it exceeds 50 parts by weight, the mechanical properties inherent to the thermoplastic resin are impaired, which is not preferable. Here, the thermoplastic resin is PVC,
Examples thereof include polycarbonate resin, polyester resin, acrylonitrile-styrene resin, and methyl methacrylate-styrene resin. As PVC, in addition to polyvinyl chloride, a vinyl chloride-based copolymer containing 70% by weight or more of vinyl chloride can be used. As the monomer to be copolymerized with vinyl chloride, ethylene, propylene, vinyl bromide, vinylidene chloride, vinyl acetate, acrylic acid ester, methacrylic acid ester and the like are used.

The impact modifier of the present invention and the thermoplastic resin are preferably mixed in powder form, for example, by a ribbon blender, a Henschel mixer or the like, and a known kneading machine,
For example, it is molded by a mixing roll, a Banbury mixer, an extruder, an injection molding machine and the like. When blending, known stabilizers, plasticizers, lubricants, colorants and the like may be added as necessary.

[0036]

The present invention will be described in detail with reference to the following examples. In the examples, "part" and "%" are "part by weight",
It means "% by weight".

The Tg of the copolymer is obtained from the Fox equation.

Example 1 (a) Production of rubber elastic body (A) A rubber elastic body (A) was synthesized according to the following composition.

1,3-Butadiene 100 parts Divinylbenzene 0.3 〃 Diisopropylbenzene hydroperoxide 0.2 〃 Sodium pyrophosphate 0.5 〃 Ferrous sulfate 0.01 〃 Dextrose 1.0 〃 Potassium oleate 0 0.5 〃 water 200 〃 The mixture having the above composition was polymerized in a pressure autoclave at 50 ° C. The polymerization was completed in 15 hours. The average particle size of the obtained rubber was 0.16 μ.

(B) Production of Multilayer Graft Copolymer (1) 30 parts of the rubber latex obtained as in the above (a) (as polymer solids), 0.6 part of semi-cured tallow potassium soap,
A solution prepared by dissolving 0.2 parts of sodium formaldehyde sulfoxylate in 120 parts of water was added, and the mixture was stirred while stirring to 70
The temperature was raised to ° C. The temperature of this latex was maintained at 70 ° C., and methyl methacrylate 39.8 was used as the layer (B) component.
Parts, 0.2 parts triallyl isocyanurate, 0.15 parts cumene hydroperoxide for 2 hours 30 minutes.
Drop for 1 minute and hold for 1 hour after the end of the dropping.
The stage graft polymerization was completed. Polymerization rate is 99.8%
Met.

To the obtained polymer latex, 0.3 part of semi-cured tallow potassium soap and 0.2 part of sodium formaldehyde sulfoxylate dissolved in 20 parts of water was added, and acrylic acid n was added as a layer (C) component. -Butyl 29.8
Parts, 0.2 parts triallyl isocyanurate and 0.15 parts cumene hydroperoxide at a temperature of 70.
The solution was added dropwise over 2 hours while maintaining the temperature at 0 ° C., and maintained for 1 hour after completion of the addition to complete the polymerization. The polymerization rate was 99.6%, and the particle diameter of the final graft copolymer was 0.21μ. In the obtained multilayer graft copolymer (1), the Tg of the butadiene-based elastic material was -85 ° C, the Tg of the layer (B) was 105 ° C, and the Tg of the layer (C) was -54 ° C.

(C) Preparation and Blend of Copolymer (2) 200 parts of nitrogen-exchanged deionized water was placed in a reaction vessel,
Dissolve 3 parts of semi-cured tallow fatty acid soap and 0.6 part of potassium persulfate, add a mixture of 90 parts of ethyl acrylate and 10 parts of methacrylic acid dropwise over 4 hours while maintaining the temperature at 70 ° C, and hold for 3 hours. Conduct and polymerize copolymer (2)
A latex was obtained. The polymerization rate was 99.9% or more.

(D) Latex blend and polymer recovery 100 parts by weight of the multilayer graft copolymer (1) latex (as solid content) was placed in a reaction kettle equipped with a stirrer, and 2 parts of copolymer (2) latex (solid content). Was added for 10 seconds with stirring, and the mixture was stirred for 15 minutes.

The latex mixture thus obtained was added to an aqueous sulfuric acid solution, acidified and coagulated, washed, dehydrated and dried to recover a polymer in powder form (Example 1-1)).

Table 1 also shows various additions of the copolymer (2).

(E) Production of compounded composition with vinyl chloride resin 100 parts of vinyl chloride resin having an average degree of polymerization of 1100, 1.0 part of tribasic lead sulfate, 0.3 part of dibasic stearic acid, lead stearate 2.4 parts, 0.3 parts of stearic acid, 0.3 parts of polyethylene wax, and 10 parts of the respective modifiers obtained in the above (d) were added, and 11 parts were added in a Henschel mixer.
The temperature was raised to 5 ° C. to obtain a uniform mixture. This vinyl chloride composition was subjected to square bar molding under the following conditions with a 30 mm single screw extruder.

Cylinder 1 150 ° C. Cylinder 2 165 ° C. Cylinder 3 180 ° C. Die 200 ° C. Screw CR = 3.0, 30 mmφ full flight screw The impact strength of the molded product is the same except that a specimen with a 2 mm deep U-notch is used. It was measured according to ASTM D-256. The results of these measurements are shown in Table 1.

[0048]

[Table 1]

From the above results, it is understood that the impact resistance improving effect is improved by blending the copolymer (2).

Example 2 In Example 1 (a), 100 parts of 1,3-butadiene was used instead of 100 parts of a 1,3-budadiene / styrene mixture in a ratio shown in Table 2, and styrene 2 was used as the component (B).
A mixture of 7.9 parts and 0.1 part of allyl methacrylate and a mixture of 11.9 parts of methyl methacrylate and 0.1 part of allyl methacrylate are polymerized in two stages, and further as a component (C). Polymerization was performed in the same manner as in (a) and (b) of Example 1 except that a mixture of 29.8 parts of 2-ethylhexyl acrylate and 0.2 part of allyl methacrylate was polymerized. 100 parts (as solid content) of the multi-layered graft copolymer (1) latex thus obtained and 4 parts (as solid content) of the copolymer (2) latex obtained in (C) of Example 1 were latex-blended, Table 2 shows the impact resistance of the vinyl chloride composition obtained in the same manner as in (d) and (e) of Example 1. Since this resin composition has the same refractive index as that of PVC in the multilayer graft copolymer, it exhibits good transparency. Similarly, the component (A),
Table 2 also shows the impact resistance improving effects of the components (B) and (C) which were changed as Examples 2-2), 2-3) and Comparative Examples 3 and 4.

[0051]

[Table 2]

The abbreviations in Table 2 are as follows. The component (B) is polymerized in two stages.

Bd: 1,3-butadiene St: Styrene MMA: Methyl methacrylate AMA: Allyl methacrylate 2EHA: 2-Ethylhexyl acrylate In Table 2, in Examples 2-1), 2-2) and Comparative Example 4. The ratio of Bd to St of the diene elastic body (A) component is Bd / St = 75/25 (part), and Bd to St of the diene elastic body (A) component of Example 2-3).
The ratio of Bd / St = 60/40 (part) and that of Comparative Example 3 are Bd / St = 30/70 (part).

From the above results, the component (A) or (C)
It can be seen that those having a high Tg of the component have little effect of improving impact resistance.

Example 3 Butyl acrylate 85 as copolymer (2) latex
Parts and 15 parts of acrylic acid were polymerized in the same manner as in (C) of Example 1 to obtain a copolymer (2) latex. 3 parts (as solid content) of this copolymer (2) latex was blended with 100 parts (as solid content) of the multi-layer graft copolymer (1) latex obtained in (a) and (b) of Example 1. Table 3 shows the impact resistance of the vinyl chloride resin composition obtained by operating in the same manner as in (d) and (e) of Example 1. As the copolymer (2) latex,
Table 3 also shows the evaluation results with the composition and the addition amount changed.

[0056]

[Table 3]

The abbreviations in Table 3 are as follows.

BA: n-Butyl Acrylate AA: Acrylic Acid IA: Itaconic Acid EA: Ethyl Acrylate MA: Methyl Acrylate MAA: Methacrylic Acid CA: Crotonic Acid From the above results, the copolymer (2) is not contained in the latex. It can be seen that those with less saturated acid have less impact improving effect, and those with more saturated acid deteriorate latex stability after blending.

Example 4 20 parts of the modifier obtained in (a) to (d) of Example 1, 80 parts of a polycarbonate resin, 0.2 part of an antioxidant and 0.1 part of calcium stearate were placed in a Henschel mixer. 30m with the cylinder temperature set to 240 ℃
Pelletized with an mφ extruder. After drying, a test piece was prepared by an injection molding machine, and the impact strength was measured by the same evaluation method as in (e) of Example 1 and the results are shown in Table 4. The results of various changes in the addition amount of the copolymer (2) are also shown in Table 4.

[0060]

[Table 4]

As described above, the modifier according to the present invention exhibits a good impact resistance improving effect on the polycarbonate resin.

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Claims (3)

[Claims] 1. A thermoplastic resin of 100 parts by weight and a crosslinking agent of 0
Polybutadiene or butadiene 5 containing ~ 5 wt%
Other vinyl compounds 5 which can be copolymerized with 0% by weight or more
A multi-layer graft copolymer in which at least two graft layers are graft-polymerized to a butadiene-based elastic body (A) composed of 0% by weight or less of the copolymer, and such a graft layer is an alkyl acrylate or an alkyl methacrylate. Each graft layer is composed of a monomer selected from the group of monomers consisting of an ester, an aromatic vinyl compound, a vinyl cyan compound and butadiene, and each graft layer contains a crosslinking agent in an amount of 0 to
The glass transition temperature of the polymer constituting 5% by weight and constituting the outermost layer (C) is 0 ° C. or lower, and the glass transition temperature of the polymer constituting the second layer (B) from the outermost layer (C) is 60 ° C. A copolymer obtained by copolymerizing 100 parts by weight of the above multi-layer graft copolymer (1) with 3 to 30% by weight of an unsaturated acid monomer and 97 to 70% by weight of a vinyl monomer copolymerizable therewith. A thermoplastic resin composition, which comprises 3 to 50 parts by weight of an impact resistance modifier formed by blending 0.1 to 20 parts by weight of a polymer (2) and has good impact resistance and moldability. 2. The impact-modifying agent according to claim 1, wherein the butadiene-based elastic material (A) accounts for 10 to 60% by weight in the multilayer graft copolymer (1), and the outermost layer (C) comprises 95-100 wt% of at least one monomer selected so that the glass transition temperature of the polymer constituting the layer (C) is 0 ° C. or less from the monomer group, and 0-5 wt% of the crosslinking agent. And a second graft layer (B) from the outermost layer (C) in which the proportion of the polymer in the multilayer graft copolymer is 10 to 60% by weight.
However, 95-100% by weight of at least one monomer selected from the monomer group so that the glass transition temperature of the polymer constituting the layer (B) is 60 ° C. or more, and the crosslinking agent 0-5. A thermoplastic resin composition, characterized in that the content of the polymer in the multilayer graft copolymer is 20 to 60% by weight. 3. The thermoplastic resin composition according to claim 1, wherein the resin mixed with the impact modifier according to claim 1 is at least one thermoplastic resin selected from vinyl chloride resins and polycarbonate resins. .