JP5436989B2 - Methacrylic resin molded body and method for producing the same - Google Patents

Description

  The present invention relates to a methacrylic resin molded body and a method for producing the same.

Generally, a method of adding a so-called elastomer component is known as a means for improving the impact resistance of a hard acrylic resin. As one of such methods, it is common to add a diene elastomer or an acrylic elastomer to an acrylic resin, but an acrylic elastomer that has a low weather resistance lowering effect is preferred particularly in outdoor applications. Has been. Many examples of acrylic polymers having a multilayer structure have been proposed as acrylic elastomers.
On the other hand, hard acrylic resin is required to have high heat resistance in addition to characteristics such as transparency and impact resistance in order to cope with the diversified use environment and advanced processing in recent years. It has become to.

As a method of improving the heat resistance as well as the impact resistance and brittleness of the acrylic resin, a method of blending acrylic polymer particles having a soft-hard multilayer structure with an acrylic resin having a maleimide unit (for example, Patent Document 1) ), Softened into a lactonized acrylic polymer having a lactone ring structure, a method of blending hard polymer acrylic polymer particles having a multilayer structure (for example, Patent Document 2), hard into a thermoplastic polymer having maleic anhydride units— A method of blending soft polymer-hard acrylic polymer particles having a three-layer structure (for example, Patent Document 3) has been proposed.
On the other hand, a cast plate (for example, Patent Document 4) in which a syrup in which multilayer structure elastic particles are dispersed at the time of polymerization of a monomer mainly composed of methyl methacrylate is injected into a cell and polymerized has been proposed. It is described that the heat workability is improved and the balance between impact resistance and workability is excellent.

JP-A-61-195149 JP 2006-8901 A JP 59-98156 Japanese Patent Laid-Open No. 08-151498

However, in the molded body obtained by the method of the above-mentioned patent documents 1 to 3, the acrylic resin produced separately and the acrylic polymer particles having a multilayer structure are dry blended, but present in the molded body. The number of foreign matters to be produced is large, and this appears as a bright spot when the molded body is irradiated with light. Therefore, it has been difficult to employ such a molded body for optical applications.
On the other hand, as a method of adding acrylic polymer particles at the beginning of polymerization of an acrylic resin without dry blending into the acrylic resin, for example, as in Patent Document 4, a monomer and a multilayer structure are formed in a molding mold. A method of polymerizing by adding acrylic resin particles is conceivable. However, a stirring means such as a mixer cannot be used during the polymerization of the monomer and the multilayered acrylic resin particles, so that it is difficult to uniformly disperse the multilayered acrylic resin particles. In Patent Document 4, it is described that 1 to 50 parts by weight of resin particles may be added to 100 parts by weight of methacrylic resin, but actually 20 parts by weight as described in the examples of this document. Is not only the limit, but also has a problem in its dispersibility, and it has been difficult to generate bright spots and to obtain sufficient impact resistance.
Accordingly, an object of the present invention is to provide a resin molded article that has few bright spots and is excellent in heat resistance and impact resistance, and a method for obtaining a resin composition obtained from the molded article.

As a result of intensive studies, the present inventor can solve the above-described problems of the prior art by performing bulk polymerization in a state where rubber-containing copolymer particles are dispersed during polymerization of an acrylic resin having a specific configuration. As a result, the present invention has been completed.
1. Methacrylic acid ester monomer alone or mixture with acrylic acid ester monomer (A), aromatic vinyl compound monomer (B), and unsaturated dicarboxylic anhydride monomer (C) in total 100 mass 1 part by mass or more and 50 parts by mass or less of the rubber-containing copolymer particles are dispersed with respect to parts, and the rubber-containing copolymer particles comprise at least three layers of the following (i) to (iii): A methacrylic resin molded article obtained by polymerizing a composition that is a multilayer structure particle having an average particle diameter of 0.04 to 0.3 μm in a mold.
(I) Methyl methacrylate 55 to 84% by mass, acrylic acid ester 1 to 20% by mass, inner vinyl layer 15 to 25% by mass containing 10 to 30% by mass,
(Ii) 60 to 75% by mass of an acrylic ester, 40 to 60% by mass of an intermediate layer containing 25 to 40% by mass of an aromatic vinyl compound,
(Iii) 30 to 50% by mass of an outer layer containing 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of another copolymerizable monomer copolymerizable with the methyl methacrylate.
2 . 2. The methacrylic resin molded article according to 1 above, wherein the monomer (C) is a compound having a structure represented by the following formula (1).

(Wherein, X represents a O, O represents an oxygen atom.)

3 . The mass ratio of the monomers (A), (B), and (C) in the molded product is (A) 30% by mass to 90% by mass, (B) 5% by mass to 40% by mass, and (C 3) The resin molded product according to 1 or 2 above, which is 5% by mass to 30% by mass.
4 . The resin composition obtained by grind | pulverizing said 1-3 .
5 . Methacrylic acid ester monomer alone or mixture with acrylic acid ester monomer (A), aromatic vinyl compound monomer (B), and unsaturated dicarboxylic anhydride monomer (C) in total 100 mass 1 part by mass or more and 50 parts by mass or less of rubber-containing copolymer particles are dispersed with respect to parts, and the rubber-containing copolymer particles comprise at least three layers (i) to (iii) below. A method for producing a molded body of a methacrylic resin composition, comprising polymerizing a composition that is a multilayer structure particle having an average particle diameter of 0.04 to 0.3 μm in a mold.
(I) Methyl methacrylate 55 to 84% by mass, acrylic acid ester 1 to 20% by mass, inner vinyl layer 15 to 25% by mass containing 10 to 30% by mass,
(Ii) 60 to 75% by mass of an acrylic ester, 40 to 60% by mass of an intermediate layer containing 25 to 40% by mass of an aromatic vinyl compound,
(Iii) 30 to 50% by mass of an outer layer containing 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of another copolymerizable monomer copolymerizable with the methyl methacrylate.
6. The method for producing a molded body of a methacrylic resin composition as described in 5 above, wherein the monomer (C) is a compound having a structure represented by the following formula (1).

（式中、ＸはＯを示し、Ｏは酸素原子を示す。）
７.成形体中の単量体（Ａ）、（Ｂ）、（Ｃ）の質量比が、（Ａ）３０質量％以上９０質量％以下、（Ｂ）５質量％以上４０質量％以下、および（Ｃ）５質量％以上３０質量％以下であることを特徴とする上記５又は６に記載のメタクリル系樹脂組成物の成形体の製造方法。

(Wherein, X represents a O, O represents an oxygen atom.)
7. The mass ratio of the monomers (A), (B), (C) in the molded body is (A) 30% by mass to 90% by mass, (B) 5% by mass to 40% by mass, and (C) The method for producing a molded body of a methacrylic resin composition as described in 5 or 6 above, which is 5% by mass or more and 30% by mass or less.

  According to the present invention, it is possible to provide a resin composition having transparency, heat resistance and impact resistance, improved dispersion of rubber-containing copolymer particles, improved strength and reduced foreign matter. .

Hereinafter, modes for carrying out the present invention will be described. (Hereinafter, the present invention will be simply described as “the present invention”, but the present invention is not limited to the embodiments shown below.)
In addition, in the following, the monomer component before superposition | polymerization is called "... monomer"("monomer" is abbreviate | omitted and may describe only a compound name.), And the structure which comprises a copolymer The unit is called “unit”.
The present invention is a mixture of methacrylic acid ester alone or the acrylic acid ester monomer (A), the aromatic vinyl compound monomer (B), anhydrous maleic acid, itaconic acid, ethyl maleic acid, itaconic acid, chlorosulfonic per 100 parts by weight of the monomer comprising a compound selected from at least one of an anhydride such as maleic acid and unsaturated dicarboxylic acid anhydride monomer (C), rubber-containing copolymer particles 1 It is a methacrylic resin molded article obtained by polymerizing a composition in which from 50 parts by mass to 50 parts by mass is dispersed in a molding die.

First, the monomer component which comprises a molded object is demonstrated.
Specific examples of the methacrylic acid ester and acrylic acid ester which are the first monomer components of the monomer composition include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacrylic acid Examples thereof include methacrylic acid esters such as n-hexyl, cyclohexyl methacrylate, and t-butylcyclohexyl methacrylate; and acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, and 2-ethylhexyl acrylate. Among these, methyl methacrylate is preferable from the viewpoint of transparency and ease of polymerization.
Specific examples of the aromatic vinyl compound (B) that is the second monomer component of the monomer composition include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2, 4 -Nuclear alkyl substituted styrene such as dimethyl styrene, ethyl styrene, p-tert-butyl styrene; α-alkyl substituted styrene such as α-methyl styrene, α-methyl-p-methyl styrene, and the like. Among these, styrene is preferable from the viewpoint of excellent thermal decomposition resistance and ease of polymerization.

The third monomer component of the monomer composition (C) is anhydrous maleic acid, itaconic acid, ethyl maleic acid, itaconic acid, unsaturated dicarboxylic acid anhydride single anhydrides such as chlorosulfonic maleate comprising at least one monomer selected mer or al.
The unsaturated dicarboxylic acid anhydride is more preferably a compound monomer having a structure represented by the following general formula (1).

In general, in cast polymerization in which a monomer is polymerized in a mold, when adding a rubber-containing copolymer particle described later to a methacrylic resin, the addition amount is about 15 parts by weight with respect to 100 parts by weight of the resin. It is known that the particles cannot be uniformly dispersed in the resin unless it needs to be suppressed and a sufficient stirring step is performed. However, by selecting any one or more of the above-mentioned third monomer components (C) as mentioned above, the addition amount is increased to 50 parts by mass, and polymerization is performed without stirring in the mold. In addition, the dispersibility of the rubber-containing copolymer particles can be ensured. The reason is that, due to the presence of polar groups present in the structure of each monomer, a network is formed due to the interaction between the polymers, and the rubber-containing copolymer particles are retained in this network, so that the dispersibility is increased. It is thought that it will be secured.
Particularly preferred monomer component (C) having high dispersibility is a compound monomer having a structure represented by the following general formula (1).

(Wherein, X represents a O, O represents an oxygen atom.)

Among the compounds represented by the general formula (1), those in which X is O are, for example, non-anhydrides such as maleic anhydride, itaconic acid, ethylmaleic acid, methylitaconic acid, chloromaleic acid and the like. Saturated dicarboxylic acid anhydride monomer is mentioned. Among these, a maleic anhydride monomer is preferable because of its excellent thermal decomposition resistance and improved heat resistance.

Since the copolymerization ratio of each monomer unit in the methacrylic resin molded product of the present invention is excellent in heat resistance and optical properties of the molded product, a methacrylic acid ester alone or a mixture with an acrylate monomer (A ) Is preferably 30% by mass to 90% by mass, the aromatic vinyl compound monomer (B) is preferably 5% by mass to 40% by mass, and the compound monomer (C) is preferably 5% by mass to 30% by mass.
When the copolymerization ratio of the methacrylic acid ester alone or the mixture (A) with the acrylate monomer is 30% by mass or more, the optical characteristics and the polymerization stability tend to be good, and it is 90% by mass or less. And heat resistance tends to be maintained. Further, when the copolymerization ratio of the aromatic vinyl compound monomer (B) is 5% by mass or more, the optical characteristics tend to be good, and when it is 40% by mass or less, the weather resistance tends to be maintained. It is in. Furthermore, when the monomer (C) is 5% by mass or more, the heat resistance tends to be good, and when it is 30% by mass or less, the colorability and the polymerization stability tend to be maintained.

More preferably, the methacrylic acid ester monomer alone or the mixture (A) with the acrylate monomer is 42% by mass or more and 83% by mass or less, and the aromatic vinyl compound monomer (B) is 12% by mass or more and 40% by mass. The compound monomer (C) is 5% by mass or more and 18% by mass or less.
More preferably, the methacrylic acid ester monomer alone or the mixture (A) with the acrylate monomer is 45% by mass to 78% by mass, and the aromatic vinyl compound monomer (B) is 16% by mass to 40%. The compound monomer (C) is 6% by mass or more and 15% by mass or less.
The blending ratio of the aromatic vinyl compound monomer (B) to the copolymerization ratio of the compound monomer (C) is preferably 1 to 3 times. If this ratio is smaller than the above range, it is difficult to obtain the effect of adding the aromatic vinyl compound, and the yield of the polymer tends to decrease, and if it is larger than the above range, it is difficult to dissolve in the monomer compounding phase. Therefore, the strength of the resin tends to be low.

  In the molded product of the present invention, a polymer obtained by copolymerizing the above-described essential constituent monomer units (A) to (C) with other monomers copolymerizable as necessary. May be included. Examples of other copolymerizable monomers used here include unsaturated carboxylic acid monomers such as methacrylic acid, acrylic acid, itaconic acid, maleic acid, fumaric acid and cinnamic acid; acrylonitrile, methacrylonitrile Unsaturated nitrile monomers such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3- Conjugated diene monomers such as hexadiene can be used, and two or more of these can be copolymerized.

Next, details of the rubber-containing copolymer particles will be described. The rubber-containing copolymer particles are added for the purpose of imparting elasticity and heat resistance to the molded body, and known rubber-containing copolymers can be used as long as they satisfy these characteristics. For example, rubber particles such as general butadiene-based ABS rubber, acrylic-based, polyolefin-based, silicone-based, and fluororubber can be used, but it is preferable to have a multilayer structure of three or more layers. Among these, acrylic rubber particles having a multilayer structure of three or more layers are more preferable. By using rubber particles having a multilayer structure of three or more layers as the rubber-containing copolymer particles, deformation of the rubber-containing copolymer particles due to heating is suppressed, and the glass transition temperature of the resin composition of the present invention (Tg) and transparency are practically good.
In the case of rubber particles having a multilayer structure, examples of the structure of each layer are as follows.

[Description of inner layer]
The copolymer forming the inner layer (ai) of the rubbery-containing copolymer particles is preferably a methacrylic copolymer, more preferably methacrylic acid, because the rubber strength and optical properties are well balanced. It is a resin obtained by copolymerizing methyl, an acrylic ester, and an aromatic vinyl compound.
What is necessary is just to use the thing similar to the methyl methacrylate illustrated as a monomer above as a methyl methacrylate in the copolymer which forms an inner layer (ai). The preferable content of methyl methacrylate is 55 to 84% by mass, and more preferably 70 to 84% by mass.
The acrylic ester monomer in the copolymer forming the inner layer (ai) is not particularly limited, but methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, acrylic Acid 2-hexyl and the like are preferable, and n-butyl acrylate and 2-hexyl acrylate are more preferable. The preferable content of the acrylate is 1 to 20% by mass. When the proportion is 1% by mass or more, thermal decomposability of the polymer is difficult to occur. On the other hand, when the proportion is 20% by mass or less, the glass transition temperature of the inner layer polymer is not lowered, and the rubber-containing copolymer The impact resistance imparting effect of the polymer particles is also increased, which is preferable. More preferably, it is 10 mass% or less.

The aromatic vinyl compound monomer in the copolymer forming the inner layer (ai) has a π-π stacking action between the intramolecular particles of the aromatic ring for the acrylate monomer. To stabilize the particles themselves. As a result, it leads to particle size control and agglomeration reduction between particles, and this further increases the dispersibility of the rubber-containing copolymer particles, leading to a reduction in the cause of foreign matter generation due to agglomeration. As the aromatic vinyl compound monomer, the same monomers as those mentioned as the second monomer component can be used, and styrene or a derivative thereof is preferably used. It is necessary to contain 15% by mass because the dispersibility of the rubber-containing copolymer particles is improved, and 25% by mass or less is necessary because the weather resistance is improved.

Furthermore, the inner layer (ai) and the later-described intermediate layer (a-ii) polymer may be chemically bonded. Examples of the copolymerizable polyfunctional monomer include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tetraethylene glycol diacrylate, 1,3-butylene glycol di (meth) acrylate, 1,4- One or more of butanediol di (meth) acrylate, allyl (meth) acrylate, triallyl isocyanurate, diallyl maleate, divinylbenzene and the like can be used in combination. Among the above compound monomers, allyl (meth) acrylate is particularly preferred because of a good balance between optical properties and impact resistance.
The ratio of the copolymerizable polyfunctional monomer used during the polymerization of the inner layer (ai) is 0.01 to 5 mass with respect to 100 mass parts of the three components of methyl methacrylate, acrylic acid ester and aromatic vinyl compound. Part is preferred. This range is preferable because the impact resistance imparting effect of the rubber-containing copolymer particles is further improved.

[Explanation of intermediate layer]
The copolymer forming the intermediate layer (a-ii) of the rubber-containing copolymer particles is preferably a copolymer exhibiting soft rubber elasticity from the viewpoint of imparting excellent toughness. Acrylic ester-based copolymers may be mentioned, and a resin obtained by copolymerizing an acrylic ester, an aromatic vinyl compound, a polyfunctional grafting agent, and a polyfunctional crosslinking agent is more preferable.
Although it does not specifically limit as acrylic acid ester which comprises an intermediate | middle layer (a-ii), Preferably, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid 2
-Use together 1 type (s) or 2 or more types from ethylhexyl etc. Of these, n-butyl acrylate and 2-hexyl acrylate are more preferable. Content of acrylic ester in the intermediate layer
Is 60-75 mass%. When the content of the acrylic acid ester is 60 mass% or more, rubber strength is good, Ru rubber strength and optical properties balance good der If it is 75 mass% or less. More preferably, it is 60-70 mass%.
The aromatic vinyl compound monomer constituting the intermediate layer (a-ii) can be the same as the inner layer (ai) for the same reason as the inner layer (ai), preferably styrene or Its derivatives. 25% by mass or more is necessary because the dispersibility of the rubber-containing copolymer particles is improved , and 40% by mass or less is necessary because the weather resistance and mechanical strength are good. More preferably, it is 30-40 mass%.

As the polyfunctional grafting agent, the same polyfunctional monomer as that used in the inner layer (ai) can be used. The polyfunctional grafting agent is used for expressing the adhesive effect between the inner layer and the intermediate layer. As content of a polyfunctional grafting agent, it is 0.05 mass part or more and 5 mass parts or less with respect to the sum of the acrylic acid ester which comprises said intermediate | middle layer (a-ii), and an aromatic vinyl compound monomer. is there. Within this range, a good crosslinking effect is obtained, the crosslinking is moderate, and the rubber elasticity effect is increased. More preferably, it is 0.5-3 mass%.
In addition, as the polyfunctional crosslinking agent, generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, dimethacrylic compounds and the like can be used, but polyethylene glycol diacrylate (molecular weight: 200 to 600) is preferable. Used. The polyfunctional crosslinking agent used here is used to generate a crosslinked structure at the time of polymerization of the intermediate layer (a-ii) and to exhibit an effect as an elastic body. However, if the polyfunctional grafting agent is used during the polymerization of the soft layer, a soft layer cross-linking structure can be generated to some extent without using a polyfunctional cross-linking agent.
And a polyfunctional crosslinking agent is 0-5 mass parts with respect to the sum of the acrylic ester and aromatic vinyl compound monomer which comprise said intermediate | middle layer (a-ii). When it is 5 parts by mass or less, the impact resistance imparting effect of the rubber-containing copolymer particles is in a better range. More preferably, it is 0-2 mass parts.

[Description of outer layer]
The copolymer forming the outer layer (a-iii) of the rubber-containing copolymer particles is preferably a methacrylic copolymer from the viewpoint of rubber aggregation suppression and compatibility with the base resin. More preferred is a copolymer containing methyl methacrylate and another copolymerizable monomer copolymerizable therewith.
The content of methyl methacrylate constituting the outer layer (a-iii) copolymer is 80 to 9
Ru 9% by mass. When it is 80% by mass or more, the optical characteristics are good, and when it is 99% by mass or less, the strength is maintained. More preferably, it is 90-99 mass%.
Although it does not specifically limit as said other copolymerizable monomer copolymerizable with said methyl methacrylate, Preferably, methyl acrylate, ethyl acrylate, acrylate n-butyl, 2-ethylhexyl acrylate 1 type or 2 types or more are used together. Of these, n-butyl acrylate and 2-hexyl acrylate are more preferable. Acrylic acid esters are preferable, and n-butyl acrylate and 2-hexyl acrylate are particularly preferable.

The ratio of the acrylate monomer in the outer layer (a-iii) is 1 to 20% by mass. When the proportion is 1% by weight or more, thermal decomposition of the polymer is less likely to occur. On the other hand, when the proportion is 20% by weight or less, the adhesiveness of the rubber-containing copolymer particles is hardly increased. Easy to handle. In addition, the compatibility with other acrylic resins is also in a preferable range, and a material excellent in impact resistance and weather resistance can be obtained.
In the outer layer (a-iii), it is preferable not to use an aromatic vinyl compound monomer from the viewpoint of weather resistance.
Furthermore, during the polymerization of the outer layer (a-iii), an alkyl mercaptan or the like can be used as a chain transfer agent in order to adjust the molecular weight for the purpose of improving the dispersibility of the base resin with respect to the monomer.

The method for producing the rubber-containing copolymer particles is not particularly limited, and can be obtained by known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and in particular, can be obtained by emulsion polymerization. preferable. In this case, in the presence of an emulsifier and an initiator, first, the monomer mixture of the inner layer (ai) is added to complete the polymerization, and then the monomer mixture of the intermediate layer (ai) is added. By completing the polymerization and then adding the monomer mixture of the outer layer (a-iii) to complete the polymerization, the multilayer structure particles can be easily obtained as a latex. The rubber-containing copolymer particles can be recovered from the latex as a powder by a known method such as salting out, spray drying or freeze drying.
An appropriate polymerization temperature for forming the polymer of each layer is selected in the range of 30 to 120 ° C., preferably 50 to 100 ° C. for each layer.

The emulsifier used for emulsion polymerization is not particularly limited, and conventionally known emulsifiers can be used. For example, a long chain alkyl carboxylate, a sulfosuccinic acid alkyl ester salt, an alkylbenzene sulfonate, and the like are preferable.
Further, the polymerization initiator is not particularly limited, and a redox may be used by using an inorganic initiator such as water-soluble persulfate or perborate alone or in combination with sulfite or thiosulfate. It can also be used as an initiator system. Furthermore, redox initiator systems such as oil-soluble organic peroxides / ferrous salts, organic peroxides / sodium sulfoxylates can also be used. In addition, peroxides and oxides in water can be removed using a reducing agent such as sodium formaldehyde sulfoxylate and ammonium persulfate.

In order to obtain rubber-containing copolymer particles having a good balance of particle stability, impact resistance, and weather resistance, it is strongly recommended to control the ratio of each layer polymer in the rubber-containing copolymer particles. That is, the ratio of each layer polymer in the rubber-containing copolymer particles is 10-30% by mass for the inner layer, 40-60% by mass for the intermediate layer, and 30-50% by mass for the outer layer. Here, when the ratio of the inner layer polymer is 10% by weight or more, seed polymerization is easily performed. On the other hand, when it is 30% by weight or less, the effect of imparting impact resistance can be obtained within a preferable range. Further, when the ratio of the intermediate layer polymer is 40% by weight or more, the impact resistance is excellent, while when it is 60% by weight or less, the weather resistance is not lowered, which is preferable. Furthermore, when the ratio of the outer layer polymer is 30% by weight or more, the stability of the particles is excellent, while when it is 50% by weight or less, the impact resistance imparting effect is excellent, which is preferable.
In addition to controlling the ratio of each layer polymer in the rubber-containing copolymer particles, it is also important to control the average particle diameter in order to obtain a resin molded product having a good balance between impact resistance and transparency. . The average particle size of the rubber-containing copolymer particles needs to be 0.04 to 0.3 μm, preferably 0.06 to 0.2 μm, and more preferably 0.08 to 0.13 μm. When the average particle size is 0.04 μm or more, the effect of imparting impact resistance is excellent, and when it is 0.3 μm or less, the transparency is excellent, which is preferable.

The resin molded product of the present invention is cast polymerized after directly injecting the mixed solution in which the rubber-containing copolymer particles described above are dispersed into the above-mentioned first to third monomer mixtures into the molding frame. Obtained by.
Compared to the case of molding a methacrylic resin obtained by dispersing both rubber-containing resin particles in a monomer composition and mixing them by dry blending. The reason why the dispersibility of the rubber-containing resin particles is high is not clear, but it is conceivable that the network due to the interaction between the polymers by the polar group of the monomer (C) is more easily retained.
The polymerization can be produced by bulk polymerization using a radical initiator, but can also be produced by solution polymerization or emulsion polymerization. Aqueous suspension polymerization is not recommended when maleic anhydride is used as the monomer component, because its water solubility is high, and it tends to be difficult to maintain a stable suspension system throughout.

As the radical initiator, those generally used can be used, and in particular, peroxide initiators lauroyl peroxide, decanoyl peroxide, and t-butylperoxy 2-ethylhexanoate are used. Then, coloring of the resin composition tends to be suppressed. Therefore, it is preferable to apply a diacyl peroxide such as lauroyl peroxide as a radical initiator for polymerizing the resin composition.
The resin molding may be a block polymer or a random polymer, but is preferably a statistical random polymer from the viewpoint of heat resistance, rigidity, and recyclability.
In order to adjust the molecular weight, a known chain transfer agent may be used. Examples of the chain transfer agent include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate). Mercaptans such as (Rate) are preferably used. These chain transfer agents may be used alone or in combination of two or more.

The molecular weight distribution range of the resin composition is preferably such that the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is in the range of 1.6 to 4.0. More preferably, it is 1.7-3.7, More preferably, it is the range of 1.8-3.5.
When Mw / Mn is 1.6 or more, the balance between the processability and mechanical properties of the resin composition tends to be good.
Moreover, when Mw / Mn is 4.0 or less, the melt fluidity is improved and the processability tends to be good.
In addition, ratio (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) says the value calculated | required by polystyrene conversion using gel permeation chromatography (GPC).

The weight average molecular weight (Mw) measured by GPC of the resin molded body is preferably 80,000 to 500,000, more preferably 90 to 300,000, and further preferably 100 to 200,000.
When the weight average molecular weight (Mw) of the resin composition is 500,000 or less, sufficient fluidity can be obtained at the time of extrusion stretching, so that melt extrusion and film formation tend to be performed without any significant trouble.
Moreover, it exists in the tendency for favorable shaping | molding stability and sufficient intensity | strength to be provided that the weight average molecular weight (Mw) of a resin molding is 80,000 or more.

The resin molded body of the present invention preferably has a Vicat value (softening point temperature) of 110 ° C. or higher, more preferably 113 ° C. or higher, and even more preferably 115 ° C. or higher. When the Vicat value is 110 ° C. or more, heat shrink deformation due to the environment of the molded body tends to be suppressed. For example, in a vehicle application, heat resistance in the vicinity of the handle portion and the meter panel portion is required. It can be suitably used for outdoor use.
The content of the rubber-containing copolymer in the first to third resin moldings described above is 1 to 50 parts by mass with respect to 100 parts by mass of the total first to third component monomers. Yes, preferably 5 to 30 parts by mass, more preferably 7 to 25 parts by mass, and the impact resistance is improved by the blending amount of the rubber-containing copolymer. When the blending amount of the rubber-containing copolymer particles is less than 1 part by mass, the impact resistance of the resulting polymer tends to be reduced, and when it exceeds 50 parts by mass, the monomer mixture contains rubbery There is a tendency that the viscosity of the mixed liquid in which the copolymer is dispersed becomes too large to perform polymerization.
Further, cast polymerization for obtaining a resin molded body is performed by, for example, two glass plates opposed to each other in parallel, or a seal material for preventing liquid leakage such as soft vinyl chloride around the metal plate and a clamp for holding the seal. It is carried out by polymerizing a so-called cell in which a gap is formed in a state in which a mixed solution in which the above-mentioned rubber-containing copolymer particles are dispersed is encapsulated in the above-mentioned monomer mixture containing the first to third components. be able to.

Examples of the initiator used for cast polymerization include peroxide radical initiators such as lauroyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, t-butylperoxy 2-ethylhexanoate, and 2,2 ′. -Azo radical initiators such as azobisisobutyronitrile, 2,2'-azobis (2,4-dimethyl-valeronitrile), 1,1-azobis (1-cyclohexanecarbonitrile) can be used. These may be used alone or in combination of two or more.
Moreover, you may use it as a redox type | system | group initiator combining the said radical initiator and a suitable reducing agent.
These initiators are usually used in the range of 0.01 to 1% by mass with respect to the monomer mixture.

Furthermore, in order to adjust the molecular weight of the resin composition, a known chain transfer agent may be used. Examples of the chain transfer agent include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, diisopropylbenzene hydroperoxide, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), Mercaptans such as pentaerythritol tetrakis (thioglycolate) are preferably used. These chain transfer agents may be used alone or in combination of two or more.
A chain transfer agent is normally used in 0.01-0.5 mass% with respect to a monomer mixture.
The cell gap is determined by the desired thickness of the cast plate, but is generally set in the range of 1 to 20 mm.

Polymerization is started by heating the cell. However, since methyl methacrylate is an exothermic polymerization reaction, if the heat of reaction is insufficiently removed or uneven heat builds up, the cast plate surface May cause a defect or a defect due to internal foaming. In order to avoid these problems, in general, circulating hot water that can easily adjust the temperature and can smoothly remove heat during the polymerization reaction or circulating hot air having a sufficient wind speed is applied as the heat medium. . The conditions for the polymerization can be appropriately determined depending on the initiator to be used, the type and amount of the chain transfer agent, the composition of the monomer mixture, and the desired cast plate thickness. Usually, the temperature range is 30 to 80 ° C. Yes, the polymerization time is 1 to several tens of hours.
In the heat treatment stage for completing the polymerization, it is preferable to apply hot air heated by boiler steam, electric heat, or the like, which can be controlled in a relatively high temperature range. Usually, the temperature range is 110 to 140 ° C., and the treatment time is 1 to 5 hours.
After the polymerization and heat treatment are completed, the glass plate or metal plate constituting the cell can be removed to obtain a resin molded body.

The resin molded body of the present invention has a haze value (turbidity) under an environment of 23 ° C., which is one of the indices indicating transparency, preferably 2.0% or less, more preferably 1.5% or less. When the haze value in a 23 ° C. environment is 2.0% or less, high transparency tends to be imparted to the molded body.
Further, the resin molded body of the present invention has a haze value in an environment at 70 ° C. of preferably 3.0% or less, more preferably 2.0% or less. When the haze value in an environment of 70 ° C. is 3.0% or less, for example, when used outdoors or in the vicinity of a light source, a decrease in transparency due to an increase in temperature tends to be suppressed. There is a tendency for the temperature dependence of the to decrease.
Resin molding of the present invention preferably has a Charpy impact strength (unnotched) of 20 kJ / ^{m 3} or more, more preferably 22KJ / ^{m 3} or more, and still more preferably 24KJ / ^{m 3} or more . When the Charpy impact strength is 20 KJ / m ³ or more, cracks and cracks are unlikely to occur in the molded article, and it can be suitably used for applications requiring impact resistance.

In the resin molded body of the present invention, other polymers can be mixed within a range not impairing the effects of the present invention.
Examples of such other polymers include polyolefin resins such as polystyrene, polyethylene, and polypropylene, polyamide resins, polyphenylene sulfide resins, polyether ether ketone resins, polyesters, polysulfones, polyphenylene oxides, polyimides, polyether imides, polyacetals, and the like. And thermosetting resins such as phenol resins, melamine resins, silicone resins, and epoxy resins.

(Additive)
Moreover, arbitrary additives can be mix | blended with the resin molding of this invention according to various objectives within the range which does not impair the effect of this invention.
The type of additive is not particularly limited as long as it is generally used for compounding resins, for example, inorganic fillers such as silicon dioxide, pigments such as iron oxide, stearic acid, behenic acid, zinc stearate, Lubricants such as calcium stearate, magnesium stearate, ethylene bisstearamide, mold release agents, paraffinic process oil, naphthenic process oil, aromatic process oil, paraffin, organic polysiloxane, mineral oil, etc. Agents, flame retardants, antistatic agents, organic fibers, glass fibers, carbon fibers, reinforcing agents such as metal whiskers, and coloring agents. These may be used alone or in combination of two or more.
The resin molded body of the present invention has an antioxidant such as a hindered phenol-based antioxidant and / or a phosphorus-based antioxidant as a heat stabilizer within the range that does not impair the effects of the present invention in order to stabilize the processing. An agent etc. can be mix | blended. In particular, a hindered phenol antioxidant is preferable.

  Examples of the hindered phenol antioxidant include pentaerythritol-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), thiodiethylene-bis (3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis (3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionamide), diethyl ((3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl) methyl) phosphate, 3,3 ' , 3 ″, 5,5 ′, 5 ″ -hexa-t-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-alkyl Sol, ethylenebis (oxyethylene) bis (3- (5-t-butyl-4-hydroxy-m-tolyl) propionate), hexamethylene-bis (3- (3,5-di-t-butyl-4-) Hydroxyphenyl) propionate), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -Trione, 1,3,5-tris ((4-tert-butyl-3-hydroxy-2,6-xylyl) methyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H ) -Trione, 2,6-di-t-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, 3,9-bis (2- (3 -(3-t-butyl-4-hydroxy-5- Butylphenyl) propionyloxy) -1,1-dimethylethyl) -2,4,8,10-spiro (5,5) undecane.

  Commercially available phenolic antioxidants may be used as hindered phenolic antioxidants. Examples of such commercially available phenolic antioxidants include Irganox 1010 (Irganox 1010: pentaerythritol tetrakis). [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], manufactured by Ciba Specialty Chemicals, Irganox 1076 (Irganox 1076: octadecyl-3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate (manufactured by Ciba Specialty Chemicals), Irganox 1330 (3,3 ', 3 ", 5,5', 5" -hexa-t-butyl-) a, a ′, a ″-(mesitylene-2,4,6-triyl Tri-p-cresol, manufactured by Ciba Specialty Chemicals), Irganox 3114: 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -1,3 5-triazine-2,4,6 (1H, 3H, 5H) -trione, manufactured by Ciba Specialty Chemicals), Irganox 3125 (Irganox 3125, manufactured by Ciba Specialty Chemicals), Sumizer BHT (Sumilizer BHT, Sumitomo Chemical), Cyanox 1790 (Cyanox 1790, manufactured by Cytec), Sumilizer GA-80 (Sumitizer GA-80, manufactured by Sumitomo Chemical), Sumilizer GS (Sumilizer GS, manufactured by Sumitomo Chemical), (Vitamin E (manufactured by Eisai)) Be mentioned Among these, Irganox 1010, Irganox 1076, Sumilizer GS, etc. are particularly preferable, and these may be used alone or in combination of two or more.

  Examples of phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite and bis (2,4-bis (1,1-dimethylethyl) -6-methylphenyl) ethyl. Ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, bis (2,4-di-t-butylphenyl) Pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis (2,4- t-butylphenyl) (1,1-biphenyl) -4,4′-diylbisphosphonite, di-t-butyl-m-cresyl-phosphonite, etc. And the like.

  A commercially available phosphorus antioxidant may be used as the phosphorus antioxidant. Examples of such commercially available phosphorus antioxidants include Irgafos 168 (Irgafos 168: Tris (2,4-di-). t-butylphenyl) phosphite, manufactured by Ciba Specialty Chemicals), Irgafos 12 (Irgafos 12: tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [1 , 3,2] dioxaphosphine-6-yl] oxy] ethyl] amine, manufactured by Ciba Specialty Chemicals, Irgafos 38: Bis (2,4-bis (1,1-dimethylethyl) ) -6-methylphenyl) ethyl ester phosphorous acid, manufactured by Ciba Specialty Chemicals), ADK STAB 329K (ADK ST) B 329K, manufactured by Asahi Denka), ADK STAB PEP36 (ADK STAB PEP36, manufactured by Asahi Denka), ADK STAB PEP-8 (ADK STAB PEP-8, manufactured by Asahi Denka), Sandstab P-EPQ (manufactured by Clariant), Weston 618 (Weston 618) GE), Weston 619G (Weston 619G, manufactured by GE), Ultranox 626 (Ultranox 626, manufactured by GE), Sumilyzer GP (Sumilizer GP, manufactured by Sumitomo Chemical), and the like. These may be used alone or in combination of two or more.

Furthermore, an ultraviolet absorber can be added to the resin molded body as long as the effects of the present invention are not impaired.
Examples of the ultraviolet absorber include benzotriazole compounds such as 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, and phenols. Compounds, oxazole compounds, malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, hindered amine compounds, triazine compounds, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

In the resin molded body of the present invention, in order to ensure excellent moldability, the ultraviolet absorber preferably has a vapor pressure (P) at 20 ° C. of 1.0 × 10 ⁻⁴ Pa or less, more preferably. Is 1.0 × 10 ⁻⁶ Pa or less, more preferably 1.0 × 10 ⁻⁸ Pa or less.
Here, being excellent in moldability means that, for example, the adhesion of a low molecular weight compound to a roll is small during film formation. For example, when a low molecular weight compound adheres to a roll, the low molecular weight compound adheres to the film surface via the roll and deteriorates the appearance and optical properties of the film, which is not preferable as an optical material. Here, the low molecular weight compound means, for example, a thermal decomposition product or a volatile matter derived from an ultraviolet absorber.
Further, in the resin molded body of the present invention, in order to ensure excellent moldability, the ultraviolet absorber preferably has a melting point (Tm) of 80 ° C. or higher, more preferably 130 ° C. or higher, More preferably, it is 160 ° C. or higher.
In order to ensure excellent moldability in the resin molded body of the present invention, the UV absorber has a weight reduction rate of 50% when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. Or less, more preferably 15% or less, and even more preferably 2% or less.
The resin molded body of the present invention may be used in further molding processes such as injection molding after pulverization to obtain a resin composition. At that time, the pulverized product may be used after being pelletized.

Examples of the present invention and comparative examples will be specifically described below, but the present invention is not limited to the examples described below.
〔Measuring method〕
The physical property measurement method and evaluation method applied in the examples and comparative examples are shown below. (1) Measurement of Vicat softening temperature (VST) An injection molded product of a resin composition obtained by roughly pulverizing the obtained resin molded body was measured according to ISO 306B50.
(2) Measurement of average particle diameter of rubber-containing copolymer particles An emulsion of rubber-containing copolymer particles is sampled, diluted with water to a solid content of 500 ppm, and UV1200V spectrophotometer Absorbance at a wavelength of 550 nm was measured using Shimadzu Corporation. From this measured value, the average particle size was determined using a calibration curve prepared by measuring the absorbance in the same manner for a sample whose particle size was measured from a transmission electron micrograph.

(3) Total light transmittance The total light transmittance of each 3 mm-thick injection-molded article was measured according to JIS-K7105.
(4) Noise measurement under 23 ° C. environment The haze value of each 3 mm thick injection-molded product was measured according to JIS-K7136.
(5) Noise measurement under 70 ° C. environment The haze value was measured in a state where each 3 mm-thick injection-molded product was kept at 70 ° C. with warm water.
(6) Charpy impact strength measurement (no notch)
The obtained cast plate and the injection molded product of the resin composition were measured according to ISO 179 / 1eU.
(7) Evaluation of bright spot (foreign matter) The obtained cast plate was cut out to 60 × 40 × 3 mm, irradiated with a lamp from the edge, and the number of visible bright spots was measured.
Moreover, the number which appears as a bright spot by irradiating a lamp from the edge of an injection molded body having a thickness of 3 mm was measured. The total number of bright spots of 5 molded bodies was measured.
First, the manufacturing method of the rubber-containing copolymer particle used in the Example and comparative example which are mentioned later is shown.

[Rubber-containing copolymer particles]
The abbreviations shown in the method for producing rubber-containing copolymer particles to be described later indicate the following compounds.
MMA: methyl methacrylate BA: n-butyl acrylate St: styrene MA: methyl acrylate ALMA: allyl methacrylate PEGDA: polyethylene glycol diacrylate (molecular weight 200)
TEGDA: Tetraethylene glycol diacrylate DPBHP: Diisopropylbenzene hydroperoxide n-OM: n-octyl mercaptan HMBT: 2- (2′-hydroxy-5′-methylphenyl) benzotriazole

(1-1) Production of rubber-containing copolymer particles (a-1)
A reactor with an internal volume of 10 L equipped with a reflux condenser was charged with 4600 mL of ion-exchanged water and 33 g of sodium dioctylsulfosuccinate as an emulsifier, and the temperature was raised to 80 ° C. in a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. Was virtually absent (substantially oxygen-free). Five minutes after adding 1.0 g of sodium formaldehyde sulfoxylate, 30% by mass of a monomer mixture consisting of MMA 220 g, BA 3.5 g, St 50 g, ALMA 0.27 g and DPBHP 0.27 g was added all at once. The remaining 70% by mass was continuously added over 20 minutes, and after completion of the addition, the mixture was further maintained for 60 minutes to complete the polymerization of the inner layer.

Next, 5 minutes after adding 0.8 g of sodium formaldehyde sulfoxylate, a monomer mixture consisting of BA 620 g, St 330 g, ALMA 15.5 g, TEGDA 4.8 g and DPBHP 2.0 g is continuously added over 60 minutes. Then, after completion of the addition, the polymerization was continued for 80 minutes to complete the polymerization of the intermediate layer.
Next, a monomer mixture composed of MMA 760 g, BA 50 g, DPBHP 1.6 g and n-OM 1.0 g was continuously added over 70 minutes, and the mixture was held for 60 minutes after the addition was completed. Next, the temperature was raised to 95 ° C. and held for 60 minutes to complete the polymerization of the outer layer.
A small amount of the emulsion containing the polymer particles thus obtained was collected, and the average particle diameter was determined by the method (2) in the method for measuring physical properties, which was 0.09 μm.
The remaining emulsified liquid is poured into a 3% by mass sodium sulfate warm aqueous solution, salted out and coagulated, then dried after repeated dehydration and washing, and the rubber-containing copolymer particles (a-1) are powdered. -Obtained as

(1-2) Production of rubber-containing copolymer particles (a-2)
As an emulsifier, 20 g of sodium dioctyl sulfosuccinate was added. Other conditions were polymerized by the same formulation as the above (a-1).
A small amount of the polymer emulsion thus obtained was collected, and the average particle diameter was determined by the method (2) in the method for measuring physical properties. As a result, it was 0.13 μm.
(1-3) Production of rubber-containing copolymer particles (a-3)
Into a reactor equipped with a reflux condenser with an internal volume of 10 L, 6868 mL of ion-exchanged water and 16 g of sodium dihexyl sulfosuccinate as an emulsifier were added, and the temperature was raised to 75 ° C. under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. Was virtually absent (substantially oxygen-free). Of the mixture (1-1) consisting of MMA 907 g, BA 33 g, HMBT 0.28 g and ALMA 0.93 g, 222 g was added all at once, and after 5 minutes, 0.22 g of ammonium persulfate was added. Forty minutes later, the remaining 719 g of (I-1) was continuously added over 20 minutes, and held for another 60 minutes after the addition was completed.

Next, after adding 1.01 g of ammonium persulfate, a mixture (I-2) comprising 1067 g of BA, St219 g, 0.39 g of HMBT, and 27.3 g of ALMA was continuously added over 140 minutes, and the mixture was further maintained for 180 minutes. did.
Next, after adding 0.30 g of ammonium persulfate, a mixture (I-3) composed of MMA 730 g, BA 26.5 g, HMBT 0.22 g, and n-OM 0.76 g was continuously added over 40 minutes. The temperature was raised to 95 ° C. and held for 30 minutes.
A small amount of the polymer emulsion thus obtained was collected, and the average particle size was determined by the method (2) in the method for measuring physical properties, and found to be 0.2 μm.
The remaining latex was poured into a 3% by weight sodium sulfate warm aqueous solution, salted and coagulated, then dried after repeated dehydration and washing, and the rubber-containing copolymer particles (a-3) were powdered. Got as.
The ratio of the mass of each layer of each polymer particle and the composition ratio in each layer are shown in Table 1.

[Examples 1 and 2]
Production of resin molded bodies (b-1) and (b-2) and resin compositions (b-5) and (b-6) obtained therefrom 72% by mass of methyl methacrylate monomer, 16% by mass of styrene monomer %, A monomer mixture composed of 12% by mass of maleic anhydride monomer, 100 parts by mass of the monomer mixture, 0.05 parts by mass of lauroyl peroxide, and 0.3 parts by mass of n-octyl mercaptan And 15 parts by mass of the rubber-containing copolymer particles (a-1) were added little by little with stirring with a screw-type stirring blade at room temperature to obtain a uniform dispersion.
A soft vinyl chloride tube was set around two tempered glass plates of 300 mm × 400 mm, and the dispersion liquid from which dissolved air was removed under reduced pressure was injected into a cell having an interval of 5 mm held by a clamp.
The cell was placed in circulating warm water adjusted to 65 ° C. for 20 hours, and then placed in 70 ° C. warm water for 2 hours. Furthermore, after placing in 120 degreeC circulation warm air for 2 hours, it cooled to room temperature and obtained acrylic resin cast board (b-1) and (b-2).
Furthermore, a part of the obtained cast plate was coarsely pulverized to obtain resin compositions (b-5) and (b-6).
The mass average molecular weight of the resin compositions (b-5) and (b-6) excluding the rubber-containing copolymer particles was 120,000.

[Examples 3 and 4]
Production of Resin Molded Body (b-3), (b-4) and Resin Composition (b-7) and (b-8) Obtained therefrom Methyl methacrylate monomer 70% by mass, styrene monomer 16% by mass %, 14 parts by mass of maleic anhydride monomer, 100 parts by mass of the monomer mixture, 0.05 parts by mass of lauroyl peroxide, and 0.25 parts by mass of n-octyl mercaptan And 15 parts by mass of the rubber-containing copolymer particles (a-2) were added little by little with stirring with a screw-type stirring blade at room temperature to obtain a uniform dispersion.
A soft vinyl chloride tube was set around two tempered glass plates of 300 mm × 400 mm, and the dispersion liquid from which dissolved air was removed under reduced pressure was injected into a cell having an interval of 5 mm held by a clamp.
The cell was placed in circulating warm water adjusted to 65 ° C. for 20 hours, and then placed in 70 ° C. warm water for 2 hours. Further, after being placed in a circulating hot air at 120 ° C. for 2 hours, it was cooled to room temperature to obtain acrylic resin cast plates (b-3) and (b-4).
Furthermore, a part of the obtained cast plate was coarsely pulverized to obtain resin compositions (b-7) and (b-8).
The mass average molecular weight excluding the rubber-containing copolymer particles (b-7) and (b-8) was 140,000.

[Comparative Example 1]
Production of Dry Blend Composition (c-1) of Acrylic Resin and Rubber Particles Cast polymerization without adding rubber-containing copolymer particles (a-1) during polymerization of resin composition (b-1) After the obtained polymer was pulverized, the rubber-containing copolymer particles (a-1) were dry blended to obtain a dry blend composition (c-1).

[Comparative Example 2]
Conventional cast plate (d-1) containing no monomer (C) and resin composition (d-2) obtained therefrom
To a monomer mixture composed of 96% by mass of methyl methacrylate and 4% by mass of methyl acrylate, 1,1-di-t-butylperoxy-3,3,3 with respect to 100 parts by mass of the monomer mixture. -0.05 part by weight of trimethylcyclohexane and 0.15 part by weight of n-octyl mercaptan were added respectively, and 15 parts by weight of the rubber-containing copolymer particles (a-3) were mixed with a screw-type stirring blade at room temperature. A small amount was added with stirring to obtain a uniform dispersion.
A soft vinyl chloride tube was set around two tempered glass plates of 300 mm × 400 mm, and the dispersion liquid from which dissolved air was removed under reduced pressure was injected into a cell having an interval of 5 mm held by a clamp.
The cell was placed in circulating warm water adjusted to 40 ° C. for 10 hours, and then placed in 70 ° C. warm water for 2 hours. Further, after being placed in a circulating hot air at 120 ° C. for 2 hours, it was cooled to room temperature to obtain a methacrylic resin cast plate (d-1).
Furthermore, a part of the obtained cast plate was coarsely pulverized to obtain a resin composition (d-2).

[Evaluation by injection molding]
The resin compositions obtained in the above examples and comparative examples were pelletized at 245 to 255 ° C. using a 30 mm vented twin screw extruder (manufactured by Nakatani Machinery Co., Ltd., type A). At that time, 300 mesh was used at the exit of the extruder as a countermeasure against foreign matter.
<Injection molding>
Various pellets obtained were subjected to a molding temperature of 240 to 260 ° C., an injection pressure of 900 kgf / cm ² , and a mold temperature of 50 ° C. using an inline script injection molding machine (Toshiba Machine Co., Ltd., IS-75S type). Predetermined test pieces were prepared and measured for physical properties.
Table 1 shows the composition blending ratio, the molding temperature of the 60 × 40 × 3 mm injection molded product, and the characteristics evaluation results.

In Example 1, the rubber-containing copolymer was dispersed during the monomer polymerization, so that the number of bright spots was maintained while maintaining transparency and heat resistance as compared with the dry blend composition of Comparative Example 1. A resin molded body and a resin composition having a small amount (less foreign matter) and an improved impact strength could be obtained. Moreover, in Example 2, although the quantity of the rubber-containing copolymer was increased to 20 parts by weight with respect to Example 1, there was no problem such as poor dispersion, so that further improvement in strength was observed.
Furthermore, in Examples 3 and 4, a resin composition having high heat resistance could be obtained by increasing the copolymerization ratio of the third monomer component.
In Comparative Example 2, the rubber-containing copolymer particles are dispersed during the monomer polymerization. However, since the copolymer composition ratio of the monomer does not include the monomer (C) of the present invention, the rubbery Dispersion of the contained copolymer particles became insufficient, and an increase in noise and an increase in the number of bright spots were observed under an environment of 70 ° C.

  Since the resin composition of the present invention has few bright spots and is excellent in optical properties such as transparency, it can be suitably used as a molded article for optical materials. For example, light guide plates, diffusion plates, polarizing plate protective films, 1/4 wavelength plates, 1/2 wavelength plates, viewing angle control used in displays such as liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions, etc. It is used for retardation films such as films, liquid crystal optical compensation films, display front plates, display substrates, lenses, touch panels, and transparent substrates used for solar cells. In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, the present invention can also be used for waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. The molded body of the present invention can be subjected to surface functionalization treatment such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, gas barrier treatment and the like.

Moreover, impact resistance and heat resistance are also improved by being excellent in the dispersibility of the rubber-containing resin particles. For example, it can be used as a part of a household appliance, transmission instrument, hobby or sports appliance, or as a body part or body part part of an automobile, ship or aircraft structure. In particular, it is suitable as an exterior part requiring impact resistance, and can be used for a bumper, a front grille, a headlamp, a body peripheral part (such as a visor), and a tire peripheral part.
In addition, automobile interior parts such as console boxes and shift lever boxes, vehicle exterior parts such as two-wheeled cowlings, home appliances, lighting equipment, mobile phones, furniture, signboards, building materials, etc., and parts that have been previously painted In addition, it can be used as a paint substitute film, and is very useful in these applications.

Claims (7)

Methacrylic acid ester monomer alone or mixture with acrylic acid ester monomer (A), aromatic vinyl compound monomer (B), and unsaturated dicarboxylic anhydride monomer (C) in total 100 mass 1 part by mass or more and 50 parts by mass or less of the rubber-containing copolymer particles are dispersed with respect to parts, and the rubber-containing copolymer particles comprise at least three layers of the following (i) to (iii): A methacrylic resin molded article obtained by polymerizing a composition that is a multilayer structure particle having an average particle diameter of 0.04 to 0.3 μm in a mold.
(I) Methyl methacrylate 55 to 84% by mass, acrylic acid ester 1 to 20% by mass, inner vinyl layer 15 to 25% by mass containing 10 to 30% by mass,
(Ii) 60 to 75% by mass of an acrylic ester, 40 to 60% by mass of an intermediate layer containing 25 to 40% by mass of an aromatic vinyl compound,
(Iii) 30 to 50% by mass of an outer layer containing 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of another copolymerizable monomer copolymerizable with the methyl methacrylate. The methacrylic resin molded article according to claim 1 , wherein the monomer (C) is a compound having a structure represented by the following formula (1).

(Wherein, X represents a O, O represents an oxygen atom.) The mass ratio of the monomers (A), (B), and (C) in the molded product is (A) 30% by mass to 90% by mass, (B) 5% by mass to 40% by mass, and (C The resin molded product according to claim 1 or 2 , wherein the content is 5% by mass or more and 30% by mass or less. The resin composition obtained by grind | pulverizing the resin molding of any one of the said Claims 1-3 . Methacrylic acid ester monomer alone or mixture with acrylic acid ester monomer (A), aromatic vinyl compound monomer (B), and unsaturated dicarboxylic anhydride monomer (C) in total 100 mass 1 part by mass or more and 50 parts by mass or less of rubber-containing copolymer particles are dispersed with respect to parts, and the rubber-containing copolymer particles comprise at least three layers (i) to (iii) below. A method for producing a molded body of a methacrylic resin composition, comprising polymerizing a composition that is a multilayer structure particle having an average particle diameter of 0.04 to 0.3 μm in a mold.
(I) Methyl methacrylate 55 to 84% by mass, acrylic acid ester 1 to 20% by mass, inner vinyl layer 15 to 25% by mass containing 10 to 30% by mass,
(Ii) 60 to 75% by mass of an acrylic ester, 40 to 60% by mass of an intermediate layer containing 25 to 40% by mass of an aromatic vinyl compound,
(Iii) 30 to 50% by mass of an outer layer containing 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of another copolymerizable monomer copolymerizable with the methyl methacrylate. The method for producing a molded body of a methacrylic resin composition according to claim 5 , wherein the monomer (C) is a compound having a structure represented by the following formula (1).

(Wherein, X represents a O, O represents an oxygen atom.) The mass ratio of the monomers (A), (B), and (C) in the molded product is (A) 30% by mass to 90% by mass, (B) 5% by mass to 40% by mass, and (C The method for producing a molded body of a methacrylic resin composition according to claim 5 or 6 , wherein the content is 5% by mass or more and 30% by mass or less.