JP3464097B2 - Multilayer graft copolymer and resin composition containing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multi-layer structure graft copolymer and a resin composition containing the same, and more specifically, it is preferably blended in a methacrylic resin,
Impact resistance, transparency, weather resistance, gloss, processability, especially strength,
The present invention relates to a methacrylic multi-layered graft copolymer which provides a resin composition having good transparency, and a methacrylic resin composition containing the same. The resin composition containing the multi-layer structure graft copolymer of the present invention maintains the transparency of the methacrylic resin at a high level and is excellent in strength, so that applications requiring these characteristics, for example, a vending machine It is useful in various fields such as the transparent front part.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resins are excellent polymers that are used in large amounts in various industrial fields because they have excellent transparency, weather resistance, gloss and processability. However, its essential drawback is poor impact resistance. Generally, as a method for improving the impact resistance of a methacrylic resin, various methods have been proposed in which a multi-layer structure having a rubber phase is introduced into the methacrylic resin to form a two-phase structure and to develop strength. For example, Japanese Patent Publication Sho 55-275
No. 76, the innermost layer containing methyl methacrylate as a main component is polymerized, and then the second layer containing butyl acrylate as a main component is polymerized in the presence of the innermost layer and further containing methyl methacrylate as a main component. It is described that the outermost layer is polymerized to form a three-layer structure, and this is mixed with a methacrylic resin to improve the impact resistance of the methacrylic resin. However, the unique beautiful appearance of the methacrylic resin, It is unavoidable that the transparency is impaired, and the improvement of impact resistance is also insufficient, and the market demand for a resin composition having sufficient impact resistance while maintaining the appearance and the transparency without impairing it, or In reality, it is hard to say that it has sufficiently satisfied the demands of the market regarding thermal stability during molding.

[0003]

DISCLOSURE OF THE INVENTION The present invention has improved transparency and impact resistance, which were not sufficient with conventional methacrylic resins, and has excellent transparency and impact resistance.
Provided is a methacrylic multi-layered graft copolymer which provides a resin composition having good weather resistance, gloss and processability, and a methacrylic resin composition containing the same.

[0004]

Means for Solving the Problems The present inventors have formulated a multi-layer structure as a means for improving impact resistance without impairing the beautiful appearance, transparency, weather resistance, gloss and processability of methacrylic resin. As a result of repeated examinations to improve by, when polymerizing each layer of the multilayer structure, by performing polymerization by selecting and combining a specific polymerization initiator, it has been found that the above problems can be solved. I arrived.

That is, the first aspect of the present invention is to use an organic peroxide in which an initiator residue introduced into a polymer is nonionic, and (a) a methacrylic acid having an alkyl group having 1 to 4 carbon atoms. One or two kinds selected from the group consisting of 40 to 100 parts by weight of alkyl ester, (b) an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms, an aromatic monomer and other copolymerizable monomer. Above 60-
A cross-linked methacrylic polymer is obtained by polymerizing a monomer mixture of 0 to 10 parts by weight and (c) a polyfunctional monomer of 0.01 to 10 parts by weight with respect to 100 parts by weight of the total amount of (a) and (b). Obtained, and then the crosslinked methacrylic polymers 10 to 4
In the presence of 0 part by weight, a peroxide whose initiator residue introduced into the polymer is an ionic group and / or hydroxyl group-containing residue is used, and (d) the alkyl group has 1 to 12 carbon atoms. 60 to 100 parts by weight of acrylic acid alkyl ester of
(E) 40 to 0 parts by weight of one or more selected from the group consisting of aromatic monomers and other copolymerizable monomers, and 100 parts by weight of the total amount of (d) and (e),
(F) 35 to 70 parts by weight of a monomer mixture consisting of 0.1 to 5 parts by weight of a polyfunctional monomer is polymerized to obtain a rubber-like polymer, and further in the presence of 60 to 90 parts by weight of the rubber-like polymer. In, using a peroxide whose initiator residue introduced into the polymer is an ionic group and / or hydroxyl group-containing residue,
(G) from 60 to 100 parts by weight of a methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group, and (h) an acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group and other copolymerizable monomers A multi-layered graft copolymer obtained by polymerizing 40 to 10 parts by weight of a monomer mixture consisting of 40 to 0 parts by weight of one kind or two or more kinds selected from the group consisting of

The second aspect of the present invention includes a resin composition comprising (A) 55 to 95% by weight of a methacrylic resin and (B) 45 to 5% by weight of the above-mentioned multilayer structure graft copolymer.

The methacrylic polymer or resin referred to in the present invention means a polymer or resin containing 40% by weight or more of a methacrylic acid alkyl ester whose alkyl group has 1 to 4 carbon atoms, and is also referred to as nonionic. Indicates that it does not substantially dissociate in water, and ionic indicates that it dissociates in water. Further, the term “initiator residue” refers to an initiator residue that initiates polymerization of the polymer when the initiator decomposes.

Multilayered graft copolymer (B) of the present invention
First, using an organic peroxide whose initiator residue introduced into the polymer is a residue containing a nonionic group and / or a hydroxyl group, (a) methacrylic acid whose alkyl group has 1 to 4 carbon atoms. One or two kinds selected from the group consisting of 40 to 100 parts by weight of alkyl ester, (b) alkyl acrylate having 1 to 12 carbon atoms in the alkyl group, aromatic monomers and other copolymerizable monomers. Above 60-0
With respect to 100 parts by weight of the total amount of (a) and (b), 0.01 to 10 parts by weight of the polyfunctional monomer (c), preferably 0.01 to 3 parts by weight, and more preferably 0. The crosslinked methacrylic polymer forming the innermost layer is obtained by polymerizing the monomer mixture consisting of 2 to 1 part by weight.

When (a) is less than 40 parts by weight, the excellent characteristics of the methacrylic resin are not exhibited, and (c) is 0.01 parts by weight per 100 parts by weight of the total amount of (a) and (b). If it is less than 10 parts by weight, the transparency is lowered, and if it exceeds 10 parts by weight, the strength developing ability is lowered.

The organic peroxide whose initiator residue introduced into the polymer is nonionic is preferably hydroperoxide or t-butylperoxyisopropyl carbonate, and hydroperoxide is t-. Butyl hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide and diisopropylbenzene hydroperoxide are preferred. These are used alone or in combination of two or more.

Examples of the (a) methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate and butyl methacrylate.
(B) Typical examples of the alkyl acrylate having an alkyl group having 1 to 12 carbon atoms include ethyl acrylate, n-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and aromatic monomers. Representative examples of styrene, α-methylstyrene, chlorostyrene and the like, and representative examples of other copolymerizable monomers include methacrylic acid, acrylic acid and hydroxyethyl methacrylate. Any of these may be used alone or in combination of two or more. Furthermore, (c)
Polyfunctional monomer Crosslinkable monomer, further crosslinkable monomer is allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, monoallyl fumarate, acrylic ester butadiene, divinylbenzene. Etc. are preferred. These are used alone or in combination of two or more.

Thereafter, the above-mentioned crosslinked methacrylic polymer 1
In the presence of 0 to 40 parts by weight, (d) an alkyl acrylate ester having 1 to 12 carbon atoms in the alkyl group is used, using a peroxide whose initiator residue introduced into the polymer is ionic. To 100 parts by weight, and one or more selected from the group consisting of (e) aromatic monomers and other copolymerizable monomers, 40 to 0 parts by weight, preferably 30 to
Monomer mixture 35 consisting of 10 parts by weight and 0.1 to 5 parts by weight of (f) polyfunctional monomer, more preferably 1 to 3 parts by weight, based on 100 parts by weight of total of (d) and (e).
A rubbery polymer is obtained by polymerizing 70 parts by weight.

The peroxide having an ionic initiator residue introduced into the polymer is preferably a persulfate or a carboxylic acid group-containing organic peroxide from the viewpoint of the degree of water solubility. Is a persulfate such as potassium persulfate, sodium persulfate or ammonium persulfate, the carboxylic acid group-containing organic peroxide is t-butylperoxymaleic acid or the like, and an initiator residue introduced into the polymer. The organic peroxide having a hydroxyl group is preferably acetylacetone peroxide. Further, examples of the initiator in which the initiator residue introduced into the polymer contains a hydroxyl group include, for example, a hydroxyl group-substituted alkyl hydroperoxide such as 1,1 dimethyl-2 hydroxyethyl hydroperoxide, a hydroxyl group-substituted alkyl peroxide, Acetylacetone peroxide is mentioned. These are used alone or in combination of two or more.

The (d) alkyl ester having 1 to 12 carbon atoms in the alkyl group may be the same as described in (b) above, and the aromatic monomer (e) and other copolymerizable monomers may be used. Such monomers may be the same as those described in (b) above, and the polyfunctional monomer of (f) may be the same as those described in (c) above. (D) is 6
When the amount is less than 0 parts by weight, the strength-developing ability is reduced, and when (e) exceeds 40 parts by weight, the strength and the transparency are deteriorated. On the other hand, if the amount is less than 0.1 parts by weight, the transparency and the strength will decrease, and if the amount exceeds 5 parts by weight, the strength will decrease.

Thereafter, in the presence of 60 to 90 parts by weight of the rubber-like composite, the initiator residue introduced into the above-mentioned polymer is ionic and / or the initiator residue introduced into the polymer is a hydroxyl group. And (h) the alkyl group has 1 to 4 parts by weight, and 60 to 100 parts by weight of the methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group, which is the outermost layer. A multi-layered graft copolymer is obtained by polymerizing 40 to 10 parts by weight of a monomer mixture consisting of 40 to 0 parts by weight of one kind or two or more kinds selected from the group consisting of 12 acrylic acid alkyl esters and other copolymerizable monomers. A polymer is obtained.

The methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group of (g) may be the same as described in (a) above, and the alkyl group of (h) has 1 to 12 carbon atoms. The acrylic acid alkyl ester may be the same as described in (b) above, and other copolymerizable monomers may be the same as those described in (b) above.

When (g) is less than 60 parts by weight, the strength is lowered, and when (h) is more than 40 parts by weight, the strength and the transparency are lowered, which causes a problem in productivity. If necessary, a polyfunctional monomer (crosslinking monomer), a molecular weight modifier such as mercaptan, or the like may be used when the outermost layer is formed.

The multi-layer structure graft copolymer (B) polymerized by using the combination of the above-mentioned polymerization initiators is used by being mixed with, for example, the methacrylic resin (A).
A methacrylic resin can be obtained while maintaining the original transparency, weather resistance, gloss and processability of the methacrylic resin.

In order to obtain such a multi-layer structure graft copolymer (B), the above-mentioned combination of initiator species is not used, and for example, an organic peroxide whose initiator residue introduced into the polymer is nonionic. When all of them are used in all the steps, each layer of the multi-layer structure graft copolymer is not clearly formed, so that the rubber-like properties are reduced and the impact resistance of the methacrylic resin composition is significantly reduced. Further, when only the peroxide having an ionic and / or hydroxyl group-containing residue as the initiator residue introduced into the polymer is used in the whole process, impact resistance is higher than that of the multilayer structure graft copolymer of the present invention. Not only is the processability poor, but the beautiful appearance of the methacrylic resin, such as the color tone, is impaired. That is, in some cases, the molded product has a strong coloring property and becomes yellowish.

Further, a peroxide having an ionic and / or hydroxyl group-containing residue as an initiator residue to be introduced into the polymer when obtaining the crosslinked methacrylic polymer latex of the innermost layer is used and then introduced into the polymer. The multi-layered graft copolymer obtained by using an organic peroxide whose initiator residue is nonionic is inferior in all of impact resistance, transparency, processability, gloss and colorability of the molded product. Becomes

The reason why a remarkable effect is exhibited by selecting and combining an initiator as in the present invention is not necessarily clear, but it is basically estimated as follows. That is, the innermost layer is mainly composed of methacrylic acid ester, and the second
Since the second layer is mainly composed of acrylic acid ester, the former is higher in terms of water solubility, and if it is somewhat, layer inversion tends to occur during polymerization. Therefore, mixing of the innermost layer and the second layer is likely to occur, and it is difficult to form a clear layer structure. Therefore, it is considered that a clear layer structure is formed by decreasing the water solubility of the innermost layer and increasing the water solubility of the second layer by selecting and combining a specific initiator as in the present invention. .

The polymerization conversion rate at the time of polymerizing the multi-layer structure graft copolymer (B) is 90 at the end of the polymerization of each layer in order to obtain a clear layer structure without the layer structure entering.
% Or more, and more preferably 95% or more. At the end of the polymerization of the multi-layer structure graft copolymer, it is preferably 95% or more, and further 9
It is preferably 8% or more. This is because when a monomer system that forms the next layer is added in a state where the polymerization conversion rate is low and the monomer remains, the clarity of each layer is decreased and the impact resistance and transparency are decreased. The polymerization conversion rate in the present invention is generally determined by a method widely used in this field, and is calculated, for example, by measuring the residual monomer amount and the solid content concentration.

The organic peroxide having a nonionic initiator residue introduced into the polymer used for the polymerization is preferably used together with a redox type polymerization initiator, and a known redox type polymerization initiation auxiliary is used as the polymerization method. Agents can be used, for example, organic peroxide / (ferrous sulfate, sodium formaldehyde sulfoxylate, ethylenediaminetetraacetate) system, organic peroxide / (ferrous sulfate, glucose, pyrophosphate) Sodium) type, organic peroxide /
(Ferrous sulfate, dextrose, sodium pyrophosphate) type and the like. Further, the peroxide whose initiator residue introduced into the polymer is ionic may be used together with a redox polymerization initiator in the same manner as the above-mentioned organic peroxide, or by a thermal decomposition reaction. You may use it as a polymerization initiator.

The multi-layer structure graft copolymer (B) used in the present invention can be produced by a conventional emulsion polymerization using a known emulsifier. The final particle size is 100 in order to obtain a multi-layered graft copolymer having well-balanced physical properties.
It is preferably 0 to 4500Å, more preferably 1500 to
It is preferably 4000Å. The multilayer structure graft copolymer latex thus obtained was spray dried,
Alternatively, as is generally known, coagulation is performed by adding a salt or an acid, and then heat treatment is performed, followed by filtration, washing, and drying to obtain a powder-form multi-layered graft copolymer. If necessary, an antiaging agent or an ultraviolet absorber which is usually added at the time of coagulation may be added.

The multi-layer structure graft copolymer obtained as described above has a good balance of appearance, transparency, weather resistance, luster, processability, etc. and can be blended with various resins. It is blended with methacrylic resin and does not impair the beautiful appearance and transparency peculiar to methacrylic resin.
Provided is a resin composition excellent in weather resistance, gloss, processability and the like. The methacrylic resin (A) used in the present invention is
As described above, it is a resin containing 40% by weight or more of a methacrylic acid alkyl ester whose alkyl group has 1 to 4 carbon atoms,
What is generally called methacrylic resin is applicable. The mixing ratio of the methacrylic resin (A) and the multilayer structure graft copolymer (B) varies depending on the use, but the methacrylic resin (A) is 55 to 95% by weight, the multilayer structure graft copolymer (B) is 45 to 5 It is preferable to mix them in an amount of 100% by weight so that the total amount becomes 100% by weight. If the methacrylic resin (A) is less than 55% by weight, the properties of the methacrylic resin are lost, and if it exceeds 95% by weight, the strength improving effect is small. The mixing method for preparing the composition of the present invention is not particularly limited, and various known methods such as extrusion kneading method and roll kneading method can be used.

[0026]

EXAMPLES Next, specific examples will be described, but these are merely examples and do not limit the contents of the present invention.

Example 1: Multilayer structure graft copolymer (a) Polymerization of crosslinked methacrylic polymer (innermost layer) A mixture having the following composition was charged into a glass reactor and heated to 80 ° C while stirring in a nitrogen stream. After heating, 96 parts by weight of methyl methacrylate, 4 parts by weight of n-butyl acrylate, 0.4 parts by weight of allyl methacrylate and the innermost layer monomer component and 0.13 parts by weight of 69% t-butyl hydroperoxide aqueous solution. Then, 25% of the mixed solution was charged at once and polymerization was carried out for 45 minutes. Subsequently, the remaining 75% of this mixed solution was continuously added over 1 hour. After the addition was completed, the temperature was maintained for 1 hour to complete the polymerization. During this period, 0.2 part by weight of sodium N-lauroyl sarcosinate was added. The average particle diameter of the polymer particles in the obtained innermost layer crosslinked methacrylic polymer latex was 1600Å
(Determined by utilizing light scattering at a wavelength of 546 μm), and the polymerization conversion rate (polymerization production amount / monomer charging amount × 10)
0) was 98%. (Parts by weight) Ion-exchanged water 220 Boric acid 0.32 Sodium carbonate 0.03 Sodium N-lauroyl sarcosinate 0.09 Sodium formaldehyde sulfoxylate (hereinafter abbreviated as SFS) 0.09 Sodium ethylenediaminetetraacetate 0.008 Sulfate first Iron 7 hydrate 0.002

(B) Polymerization of rubber-like polymer (intermediate layer) The crosslinked methacrylic polymer latex obtained in the above (a) was kept at 80 ° C. in a nitrogen stream to prepare a 69% t-butyl hydroperoxide aqueous solution of 0.1%. 1 part by weight was added and left for 30 minutes. Then, after adding 0.13 parts by weight of potassium persulfate, the monomer components were n-butyl acrylate 82 parts by weight, styrene 18 parts by weight, and allyl methacrylate 1.5 parts.
One part by weight of the monomer mixture was continuously added over 5 hours. During this period, 0.11 part by weight of potassium oleate was continuously added. After the addition of the monomer mixed solution was completed, 0.05 part by weight of potassium persulfate was further added to hold the polymerization for 2 hours in order to complete the polymerization. The average particle size of the obtained polymer was 2300Å and the polymerization addition rate was 99%.

(C) Polymerization of outermost layer The rubber-like polymer latex obtained in (b) above is heated to 80 ° C.
And adding 0.02 parts by weight of potassium persulfate, 96 parts by weight of methyl methacrylate and n-butyl acrylate 4
A mixed solution of 0.15 parts by weight of t-dodecyl mercaptan was continuously added over 1.25 hours. After the addition of the monomer mixture was completed, the mixture was kept for 1 hour to obtain a multi-layered graft copolymer latex. The average particle size of the multi-layer structure graft copolymer was 2,530Å, and the polymerization conversion rate was 99.5%. The obtained multi-layered graft copolymer latex was salted out and coagulated by a known method, heat-treated and dried to obtain a white powdered multi-layered graft copolymer.

Example 2 Multilayer Structure Graft Copolymer When polymerizing the crosslinked methacrylic polymer in the innermost layer in Example 1, 50 parts by weight of methyl methacrylate and 40 parts by weight of n-butyl acrylate were used as the innermost layer monomer components. A multi-layered graft copolymer was obtained in the same manner as in Example 1, except that 10 parts by weight of styrene and 0.4 parts by weight of allyl methacrylate were used.

Example 3 Multilayer Graft Copolymer When polymerizing the rubber-like polymer in Example 1, 0.3 parts by weight of SFS was added in place of potassium persulfate, and then the monomer component in Example 1 was added. A mixed solution with 0.4 part by weight of 34% acetylacetone peroxide (AAPO) solution was continuously added in the same manner. Further, even when polymerizing the outermost layer, 0.05 parts by weight of SFS was added without using potassium persulfate, and then the monomer component of the outermost layer of Example 1 and 0.15 part by weight of a 34% acetylacetone peroxide (AAPO) solution were added. A multi-layer structure graft copolymer was obtained in the same manner as in Example 1 except that the mixed solution was continuously added in the same manner.

Comparative Example 1: Multilayer Structured Graft Copolymer When polymerizing the rubber-like polymer in Example 1, potassium persulfate was not used as a polymerization initiator, and 0.3 part by weight of SFS was added. A mixed liquid of the monomer component in 1 and 0.05 part by weight of a 69% aqueous t-butyl hydroperoxide solution was continuously added in the same manner. Further, after adding 0.05 part by weight of SFS without using potassium persulfate when polymerizing the outermost layer, the outermost layer monomer component of Example 1 and 0.06 part by weight of a 69% aqueous t-butyl hydroperoxide solution were added. A multi-layer structure graft copolymer was obtained in the same manner as in Example 1 except that the mixed solution was continuously added in the same manner.

Comparative Example 2: Multilayer Structure Graft Copolymer When polymerizing the innermost layer crosslinked methacrylic polymer in Example 1, t-butyl hydroperoxide was not used as a polymerization initiator as described below, After charging 25% of the inner layer monomer components at once, potassium persulfate 0.04
Polymerization was started by adding 5 parts by weight. Furthermore, a multilayer structure graft copolymer was obtained in the same manner as in Example 1 except that 0.02 part by weight of potassium persulfate was added and the remaining 75% of the innermost layer monomer component was continuously added.

[0034]                                                 (Part by weight)   Ion-exchanged water 220   Boric acid 0.32   Sodium carbonate 0.03   Sodium N-lauroyl sarcosinate 0.09   Potassium persulfate 0.045

Comparative Example 3: Multilayer Structure Graft Copolymer When the methacrylic polymer crosslinked with the innermost layer in Example 1 was polymerized, t-butyl hydroperoxide was not used as a polymerization initiator and the method of Comparative Example 2 was used. The same procedure as in Example 1 was repeated except that potassium persulfate was used for the polymerization, and the subsequent rubber-like polymer was polymerized in the same manner as in Comparative Example 1. Got united.

Examples 4-6, Comparative Examples 4-6: Resin composition 98% by weight of methyl methacrylate and ethyl acrylate 2
60% by weight of methacrylic resin (methacrylic resin MG-102 manufactured by ICI) consisting of 40% by weight, 40% by weight of the above-mentioned multilayer structure graft copolymer, phosphorus-based stabilizer (TNPP)
0.1 wt% was added to 100 wt% of the total amount of the mixture, and a single screw extruder with a vent (40 m / m:
L / D = 28) was extruded at a preset temperature of 200 to 230 ° C., kneaded and pelletized. The pellets obtained are 80 ° C
After drying for 4 hours or more, injection molding at 255 ℃
A flat plate sample for physical property evaluation of × 150 × 3 (mm) was obtained. JIS K 6 at 23 ° C. using the obtained sample
The total light transmittance and haze according to 714 are
Also, ASTM D 3029-GB, weight 1.
The Gardner impact with 7 kg was measured. The results are shown in Table 1. In Table 1, MMA is methyl methacrylate, BA is n-butyl acrylate, St is styrene, A1MA is allyl methacrylate, and t-DM is t-.
Indicates dodecyl mercaptan. KPS means potassium persulfate, and tBHPO means t-butyl hydroperoxide.

From the results shown in Table 1, by incorporating the multi-layered graft copolymer of the present invention into a methacrylic resin,
It can be seen that it gives a methacrylic resin composition having excellent impact resistance and transparency (Examples 4 to 6). On the other hand, when the multi-layer structure graft copolymer of the present invention is not used, the impact resistance is significantly inferior (Comparative Examples 4 and 6) or slightly inferior (Comparative Example 5), and the transparency is insufficient. It turns out that it is (Comparative Examples 4-6).

[0038]

[Table 1]

[0039]

The multi-layer structure graft copolymer of the present invention is
By blending with methacrylic resin, it provides a molded product with excellent transparency, weather resistance, gloss, and impact resistance, which are the original characteristics of methacrylic resin, and a resin composition with excellent processability. To do.

─────────────────────────────────────────────────── --- Continued from the front page (56) References JP-A-6-313018 (JP, A) JP-A-3-199213 (JP, A) JP-A-63-122748 (JP, A) JP-A-58- 180514 (JP, A) JP-A-6-136226 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 285/00

Claims (6)

(57) [Claims] 1. An organic peroxide in which an initiator residue introduced into a polymer is nonionic is used, and (a) a methacrylic acid alkyl ester 4 having an alkyl group having 1 to 4 carbon atoms.
0 to 100 parts by weight and (b) the number of carbon atoms of the alkyl group is 1 to
12 or more selected from the group consisting of 12 acrylic acid alkyl esters, aromatic monomers and other copolymerizable monomers, 60 to 0 parts by weight, and the total amount of (a) and (b) 100 parts by weight (C) 0.01 to 10 parts by weight of a polyfunctional monomer is polymerized to obtain a crosslinked methacrylic polymer, and then 10 to 40 parts by weight of the crosslinked methacrylic polymer is present. Below, using a peroxide whose initiator residue introduced into the polymer is an ionic group and / or hydroxyl group-containing residue, (d) an alkyl acrylate having 1 to 12 carbon atoms in the alkyl group 60 to 100 parts by weight and (e) 40 to 0 parts by weight of one or more selected from the group consisting of aromatic monomers and other copolymerizable monomers.
A rubber-like polymer is obtained by polymerizing 35 to 70 parts by weight of a monomer mixture consisting of 0.1 to 5 parts by weight of the (f) polyfunctional monomer, based on 100 parts by weight of the total of (d) and (e). Furthermore, in the presence of 60 to 90 parts by weight of the rubber-like polymer,
Using a peroxide whose initiator residue introduced into the polymer is an ionic group and / or hydroxyl group-containing residue, (g) an alkyl group having a carbon number of 1 to 4 and a methacrylic acid alkyl ester 60 to 100 A monomer comprising 1 part by weight or 40 parts by weight or more of 2 or more parts selected from the group consisting of (h) an alkyl acrylate having 1 to 12 carbon atoms of an alkyl group and other copolymerizable monomers. Mixture 40
A multi-layer structure graft copolymer obtained by polymerizing 10 to 10 parts by weight. 2. The multilayer structure graft copolymer according to claim 1, wherein the organic peroxide having a nonionic initiator residue introduced into the polymer is hydroperoxide and / or t-butylperoxyisopropyl carbonate. Polymer. 3. An initiator residue introduced into a polymer, wherein the peroxide whose initiator residue introduced into the polymer is ionic is a persulfate and / or carboxylic acid group-containing organic peroxide. The multi-layered graft copolymer according to claim 1, wherein the peroxide having a hydroxyl group is acetylacetone peroxide. 4. The hydroperoxide is at least one selected from the group consisting of t-butyl hydroperoxide, cumene hydroperoxide, paramenthane hydroperoxide, and diisopropylbenzene hydroperoxide. Multi-layered graft copolymer of. 5. The persulfate is at least one selected from the group consisting of potassium persulfate, sodium persulfate and ammonium persulfate, and the carboxylic acid group-containing organic peroxide is t-butylperoxymaleic acid. Item 3. The multi-layer structure graft copolymer according to Item 3. 6. A resin composition comprising (A) 55 to 95% by weight of a methacrylic resin and (B) 45 to 5% by weight of a multi-layer structure graft copolymer according to any one of claims 1 to 5. object.