JPH0517654A - High-impact methacrylic resin composition - Google Patents

Abstract

PURPOSE:To provide a compsn. which has a good processability and is molded into an article excellent in weatherability, gloss, clarity, and impact resistance. CONSTITUTION:The first-layer copolymer having a glass transition point of 0-40 deg.C is prepd. by copolymerizing a monomer component consisting of 100wt.% the sum of an alkyl (meth)acrylate and an arom. hydrocarbon and 0. 01-5wt.% graft monomer. A multilayered graft copolymer is prepd. by copolymerizing 20-80 pts.wt. the second-layer monomer component contg. an alkyl acrylate, an arom. hydrocarbon, etc., in the presence of 3-40 pts.wt. the first-layer copolymer to form a bilayer-structure rubberlike polymer until the conversion reaches 75-94% and then adding continuously 15-50 pts.wt. graft monomer component consisting of an alkyl (meth)acrylate and other copolymerizable monomers. 1-70wt.% the multilayered graft copolymer is compounded with 99-30wt.% methacrylic resin consisting mainly of an alkyl methacrylate, thus giving the objective compsn.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a methacrylic resin composition having excellent weather resistance, gloss, transparency, impact resistance and processability.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resins have excellent weather resistance, gloss and transparency, but have the drawback of low impact resistance and their use range is limited.

As a method for imparting impact resistance while maintaining the excellent weather resistance of methacrylic resin, a method of mixing a graft copolymer having various multilayer structures has been proposed, but it still has satisfactory physical properties. Things have not been obtained. The outline and problems of the typical methods (a), (b) and (c) are shown below.

The weather resistance, gloss, transparency, impact resistance, and processability described below indicate the characteristics of a methacrylic resin composition obtained by using a methacrylic resin alone or a methacrylic resin mixed with a graft copolymer. There is.

(A) In order to impart impact resistance while maintaining the excellent weather resistance of the methacrylic resin, it is a rubber-like material containing an acrylic acid alkyl ester having excellent weather resistance as a main component and having a glass transition temperature of room temperature or lower. The polymer was graft-polymerized with a monomer component (hereinafter, referred to as a hard monomer component) such as an alkyl methacrylate having a glass transition temperature of room temperature or higher and which can be a structural unit of a relatively hard polymer. It has been proposed to mix a graft copolymer having a rubbery polymer-hard polymer bilayer structure (US Pat.
No. 3808180 and No. 3843753).

However, in this case, although the impact resistance is improved, the excellent gloss and transparency inherent to the methacrylic resin,
Especially, transparency at low and high temperatures is impaired, and satisfactory physical properties have not been obtained.

(B) In order to improve the drawbacks of the method (a), a hard monomer component such as alkyl methacrylate is added in an amount of 70 to 10
A rubber-like polymer containing alkyl acrylate as a main component is formed on the outer shell of a hard polymer containing 0% (% by weight, the same shall apply hereinafter), and a hard monomer component such as alkyl methacrylate is formed on the outer shell. It has been proposed to mix a graft copolymer having a three-layer structure of a rigid polymer-rubbery polymer-hard polymer obtained by graft-polymerizing the above (US Pat. No. 3793402).

In this method, the impact resistance can be improved while maintaining the excellent gloss of the methacrylic resin and the excellent transparency including low and high temperatures, but the core of the rubber-like polymer is hard. Since it has a polymer component, the effect of improving impact resistance is insufficient as compared with method (a).

(C) In order to improve the drawbacks of the methods (a) and (b), an acrylic acid alkyl ester is added to a hard monomer component such as methacrylic acid alkyl ester which is the innermost layer of the method (b) in an amount of 35 to A semi-rubber having a glass transition temperature close to room temperature by being copolymerized with 45% and further cross-linked with a cross-linkable monomer having two or more acryloyloxy groups and / or methacryloyloxy groups in one molecule. -Like polymer is contained in the innermost layer, a rubber-like polymer mainly composed of alkyl acrylate is formed on the outer shell, and a hard monomer component such as methacrylic acid alkyl ester is graft-polymerized on the outer shell. There has been proposed a method of mixing a graft copolymer having a semi-rubbery-rubbery-hard three-layer structure (US Pat. No. 4730023, JP-A-62).
-230841).

However, in this method, the above method (a) and
(b) It shows transparency and impact resistance that are almost in the middle of the method,
The impact resistance of method (a) and the transparency of method (b) are not reached.
The shortcomings of one method have not been fundamentally resolved.

[0011]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of obtaining a methacrylic resin composition excellent in weather resistance, gloss, transparency, impact resistance and processability.

[0012]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that as a multi-layer structure graft copolymer to be blended with a methacrylic resin, a specific two-layer structure rubber-like compound is first prepared. Before the polymerization of the polymer, and further the polymerization of the two-layer structure rubbery polymer is completed, continuous addition of the graft monomer component is started in the presence of the unreacted monomer of the second layer. The inventors have found that the above problems can be solved by polymerizing, and have completed the present invention.

That is, according to the present invention, at least one kind of methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and 70 to 40% of an aromatic hydrocarbon, and an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms are used. By polymerizing 3 to 40 parts (part by weight, hereinafter the same) of the first layer monomer component consisting of 30 to 60% of ester and 0.01 to 5% of graft-bonding monomer to 100% of these monomer components. In the presence of the first layer copolymer having a glass transition temperature of 0 to 40 ° C., an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms 60
.About.100%, aromatic hydrocarbons 40 to 0%, and graft bondable monomers 0.01 to 5% and crosslinkable monomers 0 to 5% with respect to 100% of these monomer components. Polymerization conversion of the second layer monomer component is initiated by initiating polymerization of 20 to 80 parts of the second layer monomer component having a glass transition temperature of 0 ° C. or less to polymerize the two-layer structure rubber-like polymer. Rate is 75 ~
When it reached 94%, in the presence of the unreacted second layer monomer component, the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms has a carbon number of 70 to 100%, and the carbon number of the alkyl group has Graft monomer component consisting of 30 to 0% of acrylic acid alkyl ester of 1 to 12 and 0 to 20% of a monomer copolymerizable therewith, and having a glass transition temperature of 40 ° C. or more when polymerized by only these A multi-layered graft obtained by continuously adding 15 to 50 parts and performing graft polymerization so that the total amount becomes 100 parts, and the polymerization conversion rate at the end of the polymerization is 97% or more based on 100 parts of the total amount. Copolymer (A) 1-
Impact resistance consisting of 70%, methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms 70 to 100% and methacrylic resin (B) 99 to 30% comprising 30 to 0% of a monomer copolymerizable therewith -Related methacrylic resin composition.

[0014]

EXAMPLE A multi-layer structure graft copolymer (A) used in the present invention was prepared by mixing with a methacrylic resin (B).
While maintaining the weather resistance, gloss, and transparency of conventional technology, impact resistance and workability have been greatly improved, resulting in
It is a component that gives a methacrylic resin composition having excellent weather resistance, gloss, transparency, impact resistance, and processability.

Further, the multi-layered graft copolymer (A)
Is a semi-rubbery polymer of the first layer, on which a second layer monomer component of the rubbery copolymer is polymerized (two-layer rubbery polymer), It is obtained by polymerizing a graft monomer component which becomes a copolymer.

The first layer copolymer, which is the innermost layer of the multi-layer structure graft copolymer (A), includes a methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group, which is a hard monomer component, and an aromatic compound. 70-40 at least one kind of group hydrocarbon
%, Preferably 60 to 40%, and the number of carbon atoms of the alkyl group is 1 to
12 to 30% acrylic acid alkyl ester, preferably
A semi-rubber polymer having a glass transition temperature of 0 to 40 ° C, preferably 0 to 35 ° C, which is composed of 40 to 60%, is used, and the innermost layer (core portion) of the multi-layered graft copolymer (A) is used. As a result, it has both properties of a rubbery polymer and a hard polymer, and thus lacks gloss and transparency in the method (a), and (b)
The problem of lack of impact resistance in the method can be improved. When the composition range deviates from the above range and the glass transition temperature exceeds 40 ° C., the rubber property of the two-layer structure rubber-like polymer having the glass transition temperature as the core decreases, so that the impact resistance decreases, and If the temperature is lower than 0 ° C, the effect of forming a semi-rubber is lost, and the gloss and transparency are deteriorated, which is not preferable.

Further, the first layer copolymer is not an ordinary crosslinkable monomer such as a crosslinkable monomer having two or more acryloyloxy groups and / or methacryloyloxy groups in one molecule. The total amount of only the graft-bonding monomer, that is, the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and at least one kind of aromatic hydrocarbon, and the acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms. 0.01 to 5%, preferably 0.01 to 3%, is used to form a rubber-like polymer having an alkyl acrylate as a main component in its outer shell. After making good use of it, the adhesion between the first layer and the second layer becomes good, and the problems of lack of gloss, transparency and impact resistance in the method (c) can be solved.
Impact resistance of method (a), which could not be achieved by conventional technology,
(b) It is possible to achieve both the gloss and transparency of the method.

Methyl methacrylate is a typical example of the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, styrene is a typical example of the aromatic hydrocarbon, and acrylic acid having an alkyl group having 1 to 12 carbon atoms. Typical examples of alkyl esters include n-butyl acrylate and acrylic acid.
2-ethylhexyl and the like can be mentioned respectively.

Further, regarding the crosslinkable monomer and the graft bondable monomer and their distinction, US Pat. No. 3,808,180
No. 3793402, and many other documents, which are clearly distinguished.

That is, the crosslinkable monomer has the same reactivity of a plurality of functional groups, and has an acryloyloxy group and / or methacryloyl in one molecule used in the innermost layer of the method (c). A crosslinkable monomer having two or more oxy groups, such as 1,3-butylene dimethacrylate,
1,4-butanediol diacrylate, ethylene glycol dimethacrylate, etc. are included in this. Typical examples of the crosslinkable monomer include divinylbenzene and the like.

The graft-bonding monomer is one in which the reactivity of at least one functional group is different from the reactivity of other functional groups, such as methacrylic acid allyl ester.
Typical examples are acrylic acid allyl ester and terephthalic acid diallyl ester.

Further, the glass transition temperature is a physical property well known in this field as described in, for example, Polymer Handbook 2nd Edition (1975), and its measuring method is also described in the above-mentioned document. .

As the glass transition temperature of the copolymer in the present invention, the value calculated by the following formula is used.

1 / Tg = W _a / T g _a + W _b / T g _b (T g: glass transition temperature of copolymer composed of components a and b, T g _a : glass transition temperature of component a alone, W _a : component a Weight fraction of Tg _b , glass transition temperature of component b alone,
W _b : Weight fraction of component b) Polymerization of the first layer copolymer is 97% or more, further 98% or more, particularly 99% or more in terms of polymerization conversion so as not to affect the composition of the second and subsequent layers. It is preferably polymerized.

The second type of the multi-layer structure graft copolymer (A)
As the layer, an alkyl acrylate whose alkyl group has 1 to 12 carbon atoms is 60 to 100%, preferably 70 to 90%, aromatic hydrocarbon is 40 to 0%, preferably 30 to 10% and these monomers. Graft-bonding monomer 0.01 per 100% of component
-5%, preferably 0.01-3% and crosslinkable monomer 0
It is composed of 5%, preferably 0 to 3%, and when it is polymerized only by these, the glass transition temperature is 0 ° C or lower, preferably -100.
A rubbery polymer that is ~ 0 ° C is used. Since the rubber-like copolymer having a glass transition temperature of 0 ° C. or less is used as the second layer of the two-layer structure rubber-like polymer, the above-mentioned semi-rubber-like first polymer is used.
It becomes possible to fully exhibit the properties of the two-layer structure rubber-like polymer as a rubber-like polymer after encapsulating the layer copolymer.

If the composition is out of the above range, the difference in the refractive index with the methacrylic resin to be mixed becomes large and the transparency is lowered, or the glass transition temperature of the second layer monomer component alone is 0 ° C. And the rubbery property of the two-layer structure rubbery polymer is impaired and the impact property is lowered, which is not preferable.

A typical example of the acrylic acid alkyl ester whose alkyl group has 1 to 12 carbon atoms is acrylic acid n-
Butyl, 2-ethylhexyl acrylate, and the like, and typical examples of the aromatic hydrocarbon include styrene and α-methylstyrene.

Further, the above-mentioned multi-layer structure graft copolymer
As the third layer of (A), the methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms is 70 to 100%, preferably
80 to 100%, more preferably 85 to 100%, and an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms 30 to 0%
%, Preferably 20 to 0%, more preferably 15 to 0%, and 0 to 20%, preferably 0 to 15%, of a monomer copolymerizable therewith. A hard polymer having a temperature of 40 ° C. or higher, preferably 50 to 150 ° C. is used.

When the composition range and the glass transition temperature are out of the above ranges, impact resistance, processability and powder properties of the graft copolymer obtained by acid precipitation are deteriorated, which is preferable. Absent.

Methyl methacrylate is a typical example of the methacrylic acid alkyl ester whose alkyl group has 1 to 4 carbon atoms, and ethyl acrylate is a typical example of the acrylic acid alkyl ester whose alkyl group has 1 to 12 carbon atoms. , N-butyl acrylate and the like. Further, as the copolymerizable monomer, styrene, acrylonitrile,
Representative examples are methacrylic acid and acrylic acid.

If necessary, a graft-bonding monomer, a cross-linking monomer, a molecular weight modifier such as mercaptan, etc. may be used together when the third layer is formed.

The third layer of the multi-layered graft copolymer (A) is polymerized so that the conversion rate of the second layer monomer component is 75 to 94%,
Preferably, when 80 to 92% is reached, the continuous addition of the graft monomer component is started in the presence of the unreacted second layer monomer component to polymerize.

In the present invention, the polymerization conversion rate is calculated by measuring the amount of residual monomer and the solid content concentration, etc., as is generally performed in this field.

When the polymerization conversion rate of the second layer monomer component when the graft monomer component is added is less than 75%, 2
The two-layer structure of the layered rubber-like polymer becomes incomplete, the rubber properties are impaired, and the impact resistance is lowered. At the same time, the multi-layered graft copolymer obtained is salted out or acidified to obtain a powder. The state (powder characteristics) deteriorates, which is not preferable. On the other hand, if it exceeds 94%, the effect of improving the workability and impact resistance by suppressing the polymerization conversion rate to be low becomes insufficient, which is not preferable. The continuous addition of the graft monomer component is preferably carried out at a rate of 3 to 40 parts, more preferably 5 to 30 parts per hour, and the polymerization is carried out at a polymerization conversion ratio at the end of the graft polymerization. 97% or more, preferably 98% or more, more preferably 100% of the total amount of
It is performed until it reaches 99% or more.

By carrying out the polymerization in this way,
Taking advantage of the excellent properties of the two-layer structure rubber-like polymer composed of the first layer and the second layer, the adhesion between the second layer and the third layer (graft layer) is improved, and the impact resistance and the processing are improved. It can greatly improve the fluidity, especially the fluidity at the time of melting. In addition to these physical properties, the polymerization time of the graft copolymerization is shortened, and the productivity at the time of producing the graft copolymer is also improved.

The ratio of the first layer to the third layer in the multi-layer structure graft copolymer (A) is such that the total amount is 100 parts, and the first layer monomer components 3 to 40 serving as the first layer. Part, preferably 3 to 30 parts, second layer monomer component to be the second layer 20 to 80
Parts, preferably 30 to 80 parts, and 15 to 50 parts, preferably 15 to 45 parts, of the graft monomer component forming the third layer. When the proportion of the monomer component of the first layer is less than 3 parts, the effect of forming the rubber-like polymer composed of the first layer and the second layer into two layers is not observed, and the gloss and transparency are deteriorated. On the other hand, if it exceeds 40 parts, the rubbery properties of the rubber-like polymer will be impaired and the impact resistance will be reduced, such being undesirable. Further, when the ratio of the second layer monomer component is less than 20 parts, the impact resistance is lowered, and when it exceeds 80 parts, the powder property of the multi-layered graft copolymer obtained is It deteriorates and is not preferable. Further, when the ratio of the graft monomer component is less than 15 parts, the powder properties are deteriorated, and when it exceeds 50 parts, the impact resistance is deteriorated.

The multi-layered graft copolymer (A) used in the present invention is produced by a usual emulsion polymerization method. The particle size of the graft copolymer is 1000 to 5000 A, which is glossy,
1000-4500A, which is preferable in terms of transparency and impact resistance.
Is more preferable.

The multi-layered graft copolymer latex thus obtained is spray-dried, salted out or acid-deposited, filtered, washed and dried to obtain the multi-layered graft copolymer (A). Antiaging agents, ultraviolet absorbers and the like which are usually added at the time of coagulation may be added.

Methacrylic resin (B) used in the present invention
Is a methacrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms of 70 to 100%, and a monomer copolymerizable therewith 30 to 30%.
It is a methacrylic resin consisting of 0%.

A typical example of the methacrylic acid alkyl ester having 1 to 4 carbon atoms in the alkyl group is methyl methacrylate. Examples of the copolymerizable monomer include alkyl acrylates having an alkyl group having 1 to 12 carbon atoms, aromatic hydrocarbons, and the like.
Representative examples include ethyl acrylate and styrene.

In the present invention, the composition of the present invention can be obtained by mixing the multilayer structure graft copolymer (A) and the methacrylic resin (B). The mixing ratio of the multilayer structure graft copolymer (A) and the methacrylic resin (B) varies depending on the application, but the multilayer structure graft copolymer (A) 1 to 70%,
Preferably from 5 to 60%, methacrylic resin 99 to 30
%, Preferably 95-40%.

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.

Next, the composition of the present invention will be described based on specific examples, but these are merely examples and do not limit the content of the present invention.

Example 1 (a) Production of seeds used for production of two-layer rubbery polymer (part) Distilled water 250 Potassium rosinate 0.5 Sodium oleate 0.5 Demol N 0.2 Sodium formaldehyde sulfoxylate (SFS) 0.2 Na ₃ PO ₄ · 12H ₂ O 0.45 EDTA · 2Na 0.008 ferrous sulfate heptahydrate 0.002 A mixture of the above composition was charged into a glass reactor and heated to 70 ° C with stirring under a nitrogen stream. And methyl methacrylate
5 parts of a mixture of 50 parts, 40 parts of n-butyl acrylate, 10 parts of styrene, 1.0 part of allyl methacrylate and 0.4 part of cumene hydroperoxide as the first layer monomer component.
% Was charged and polymerized, then 95% of the remaining mixture was added dropwise over 5 hours. After the completion of the addition, the polymerization was completed 3.0 hours later to complete the polymerization.

The yield of the obtained polymer was 98%, and the average particle size of the latex was 900 A.

Demol N is a naphthalene sulfonic acid formalin condensate manufactured by Kao Atlas Co., Ltd.

(B) Polymerization of 2-layer structure rubber-like polymer and graft copolymer Using the latex obtained in (a) as a seed, seed polymerization was carried out.

(Part) Distilled water 220 Latex obtained with 220 (a) (solid content) SFS 0.30 EDTA.2Na 0.008 Ferrous sulfate heptahydrate 0.002 A mixture of the above composition was charged into a glass reactor and nitrogen was added. After heating to 70 ° C under stirring in an air stream, 3.5 parts of methyl methacrylate with the same composition ratio as the seed, n-butyl acrylate 2.8 parts, styrene 0.7 parts, allyl methacrylate 0.07
A mixture of 0.03 part of the first layer monomer component and 0.03 part of cumene hydroperoxide was continuously added over 0.5 hour. After the addition was completed, the polymerization was further performed for 1 hour to obtain a first layer copolymer. The average particle size was 1100 A and the conversion rate was 99%. Then n-butyl acrylate
A mixture of the second layer monomer component consisting of 44.8 parts, styrene 11.2 parts, allyl methacrylate 0.56 parts and cumene hydroperoxide 0.22 parts was continuously added over 6 hours. Simultaneously with the addition of the mixture, 0.7 parts of sodium oleate in 5% aqueous solution was continuously added for 6 hours. After the addition is complete, 0.05 part of cumene hydroperoxide is added, and further post-polymerization is performed,
Polymerization proceeded to a conversion rate of 88%. At this point, a mixture of 28.5 parts of methyl methacrylate, 1.5 parts of n-butyl acrylate and 0.15 parts of cumene hydroperoxide and 0.15 parts of t-dodecyl mercaptan was continuously added over 2 hours. did. After the completion of the addition, 0.05 part of cumene hydroperoxide was added, and after further polymerization for 2 hours, a graft copolymer latex was obtained. The conversion was 99% and the particle size was 2200A.

The obtained graft copolymer latex was acid-deposited and dehydrated and dried to obtain a target graft copolymer. The powder properties of the obtained graft copolymer were visually observed.

Next, 65% of a methacrylic resin consisting of 97% of methyl methacrylate and 3% of ethyl acrylate, 35% of the obtained graft copolymer and 1.0% of a phosphorus-based stabilizer were added to the above mixture. Using a single-screw extruder with a vent (40 m / m 2, L / D = 28), the mixture was extruded at a preset temperature of 230 ° C, kneaded, and pelletized. The pellets obtained are 100
After drying at ℃ for 4 hours, injection molding at the set temperature of 230 ℃, 100
A flat plate sample for physical property evaluation of x150 x3 (thickness) (mm) was obtained.

Using the obtained sample, the glossiness according to JIS-K-7105 (incident angle 60 °), the light transmittance and the haze value according to ASTM D1003, the Gardner impact with ASTM D 3029-GB, and the weight of 1.8 kg Was measured. Further, the obtained pellets were dried at 100 ° C. for 4 hours, and then the melt index according to ASTM D 1238-1 was measured. The results are shown in Table 1.

In Table 1, MMA is methyl methacrylate, BA is butyl acrylate, St is styrene, AlMA is allyl methacrylate, BDMA is 1,4-butanediol dimethacrylate, and ○ in the powder characteristics is industrial. Can be produced, and x indicates industrially impossible.

Examples 2-3 and Comparative Examples 1-8 Types and amounts of monomers, graft binders and crosslinking agents used,
Multilayer structure graft copolymer as in Example 1 except that the conversion rate of the second layer monomer component was changed as shown in Table 1.
I got (A). The powder characteristics were evaluated in the same manner as in Example 1. Further, the glossiness, light transmittance, haze value, Gardner impact, and melt index were measured in the same manner as in Example 1. The results are shown in Table 1.

[0054]

[Table 1]

From the results shown in Table 1, by mixing the multi-layer structure graft copolymer (A) used in the present invention with a methacrylic resin, a methacrylic resin excellent in all of gloss, transparency, impact resistance and processability was obtained. It can be seen that compositions are obtained (Examples 1 to 3).

On the other hand, when the specific two-layer structure rubber-like polymer used in the present invention is not used, gloss and transparency are lowered,
The impact resistance is also insufficient (Comparative Examples 1 to 3), and even when a specific two-layer structure rubbery polymer is used, the conversion rate of the second layer monomer component is out of the range of the present invention. It was found that, in the case of smoking, sufficient workability, impact resistance, powder specification, etc. could not be obtained (Comparative Examples 4 to 5). Further, when a graft copolymer obtained by carrying out a conventional graft polymerization on a conventional rubber-like polymer is used, it is found that sufficient gloss, transparency, impact resistance and processability cannot be obtained (Comparative Example 6 ~ 8).

[0057]

EFFECTS OF THE INVENTION The use of the methacrylic resin composition of the present invention makes it possible to obtain a molded article which is excellent in processability and is excellent in weather resistance, gloss, transparency and impact resistance.

Claims (3)

[Claims] 1. A methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and 70 to 40% by weight of an aromatic hydrocarbon, and an acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms 30 to 40% by weight. 60% by weight and 100% by weight of these monomer components are graft-bondable monomers.
In the presence of the first layer copolymer having a glass transition temperature of 0 to 40 ° C., which is obtained by polymerizing 3 to 40 parts by weight of the first layer monomer component consisting of 01 to 5% by weight, carbon of an alkyl group is present. Number is 1-12
60% to 100% by weight of alkyl acrylate, 40% to 0% by weight of aromatic hydrocarbon, and 0.01% to 5% by weight of graft-bonding monomer and 0% of crosslinking monomer to 100% by weight of these monomer components. ˜5% by weight, and when polymerized with only these, the polymerization of 20 to 80 parts by weight of the second layer monomer component having a glass transition temperature of 0 ° C. or less is initiated to polymerize the two-layer structure rubbery polymer. , The polymerization conversion rate of the second layer monomer component is
When it reaches 75 to 94% by weight, in the presence of the unreacted monomer component of the second layer, an alkyl group having a carbon number of 1 to 4 is a methacrylic acid alkyl ester 70 to 100% by weight, an alkyl group Of 30 to 0% by weight of an alkyl acrylate having 1 to 12 carbon atoms and 0 to 100% of a monomer copolymerizable therewith
Graft monomer component 15 to 50, which is composed of 20% by weight and has a glass transition temperature of 40 ° C or higher when polymerized only with these components.
Continuous addition of 1 part by weight was started, and graft polymerization was performed so that the total amount became 100 parts by weight.
Multilayer structure graft copolymer (A) obtained in an amount of 97% by weight or more based on 0 parts by weight 1 to 70% by weight, alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms 70 to 100% by weight % And monomers copolymerizable therewith
Methacrylic resin (B) consisting of 30 to 0% by weight 99 to 30% by weight
An impact-resistant methacrylic resin composition comprising 2. The second layer monomer component comprises an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms of 70 to 90% by weight, an aromatic hydrocarbon of 30 to 10% by weight, and 100 parts of these monomer components. The composition comprises 0.01 to 5% by weight of a graft-bonding monomer and 0 to 5% by weight of a crosslinkable monomer, based on% by weight.
The resin composition described. 3. The polymerization conversion rate of the second layer monomer component is from 80 to
When it reaches 92% by weight, the graft monomer component 15-50
The resin composition according to claim 1, wherein continuous addition of parts by weight is started and graft polymerization is carried out so that the total amount becomes 100 parts by weight.