Resin composition and resin molded article

Abstract

To provide a resin composition and a resin molded article which have excellent transparency combined with impact resistance, and which are suitable for recycling.SOLUTION: A resin composition contains acrylic rubber particles (A) including a structural unit derived from an aromatic vinyl compound represented by the following formula (I). A resin molded article is obtained by molding the resin composition. (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a resin molded article having excellent transparency and impact resistance. [Background technology]

[0002] Among resins, (meth)acrylic resins are popular due to their excellent appearance, dimensional stability, and chemical resistance. It is widely used in many applications, including materials for residential facilities such as bathroom vanities, bathtubs, and flush toilets; building materials; and vehicle components such as interior and exterior materials for vehicles.

[0003] In recent years, research into chemical recycling of various resin products has accelerated, and there is a demand for recycled products to have the same performance as before. In particular, chemical recycling involves subjecting waste plastic products to thermal decomposition or other processes, which cut the polymer chain and convert it into monomers. However, this process introduces various impurities as by-products. The inclusion of large amounts of these impurities results in a resin composition with low purity, which significantly impacts the performance of the resulting resin moldings and products. Therefore, it is important to obtain highly pure monomers through chemical recycling, and there is a demand for material designs that are suitable for chemical recycling and have high recyclability.

[0004] Resin products also require impact resistance, and to ensure impact resistance and transparency, a method of reinforcing the resin by adding rubber containing a copolymer having structural units derived from styrene, as described in Patent Document 1, is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 077614 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it has been found that a resin composition containing a rubber compounded with a copolymer having a structural unit derived from styrene described in Patent Document 1 and a resin molded article thereof have a problem that impurities are likely to be mixed in through a recycling process and the transparency is impaired. In Patent Document 1, when no rubber is contained, the transparency is less likely to be significantly impaired even after recycling, but the impact resistance becomes poor. For this reason, there is a demand for a material having excellent transparency and impact resistance and high recyclability.

[0007] Therefore, an object of the present invention is to provide a resin composition and a resin molded article having excellent transparency and impact resistance and suitable for recycling.

Means for Solving the Problems

[0008] The above problems are solved by the following present invention.

[0009] [1] A resin composition containing acrylic rubber particles (A) containing a structural unit derived from an aromatic vinyl compound represented by the following formula (I).

[0010]

Chemical formula

[0011] (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group.)

[0012] [2] The resin composition according to [1], wherein the acrylic rubber particles (A) are particles having a two-layer structure or more.

[0013] [3] The resin composition according to [2], wherein the acrylic rubber particles (A) are particles having a three-layer structure.

[0014] [4] The resin composition according to any one of [1] to [3], which contains a (meth)acrylic polymer (X) in the resin composition.

[0015] [5] The resin composition according to [4], wherein the content of the (meth)acrylic polymer (X) is 50% by mass or more based on the resin composition.

[0016] [6] The resin composition according to [4] or [5], wherein the content ratio of the repeating unit derived from methyl methacrylate in the (meth)acrylic polymer (X) is 50% by mass or more.

[0017] [7] The resin composition according to any one of [1] to [6], wherein the content of the structural unit derived from the aromatic vinyl compound represented by the formula (I) is 1.0% by mass or more and 30.0% by mass or less based on the whole of the acrylic rubber particles (A).

[0018] [8] The resin composition according to any one of [1] to [7], wherein the aromatic vinyl compound represented by the formula (I) is one or more selected from the group consisting of m-vinyltoluene, p-vinyltoluene, and 4-tert-butylstyrene.

[0019] [9] When GC-MS measurement is performed using a column Rtx1701 manufactured by Restek at a furnace temperature of 370 °C and a heating time of 3 minutes, the amount of toluene detected is 100 mass ppm or less based on the whole of the resin composition. The resin composition according to any one of [1] to [8].

[0020]

[10] The resin composition according to any one of [1] to [9], which is a resin composition for recycling.

[0021]

[11] A resin molded article formed by molding the resin composition according to any one of [1] to

[10] .

[12] A vehicle member formed by molding the resin composition according to any one of [1] to

[10] .

[13] An optical member formed by molding the resin composition according to any one of [1] to

[10] .

[14] A cosmetic container formed by molding the resin composition according to any one of [1] to

[10] .

[15] A food container formed by molding the resin composition according to any one of [1] to

[10] .

[16] A film formed by molding the resin composition according to any one of [1] to

[10] .

[17] A toy formed by molding the resin composition according to any one of [1] to

[10] .

[18] A building material formed by molding the resin composition according to any one of [1] to

[10] .

[19] Communication equipment formed by molding the resin composition according to any one of [1] to

[10] .

[0022]

[20] A method for manufacturing a resin molded body, which comprises manufacturing a resin molded body by molding a resin composition containing acrylic rubber particles (A) containing a structural unit derived from an aromatic vinyl compound represented by the following formula (I).

[0023] [Chemical formula]

[0024] (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group.)

[0025]

[21] The method for manufacturing a resin molded body according to

[20] , wherein the molding is injection molding. [Advantages of the Invention]

[0026] According to the present invention, it is possible to provide a resin composition and a resin molded body having excellent transparency and impact resistance and suitable for recycling. [Brief Description of the Drawings]

[0027]

Figure 1

[0028] Hereinafter, the present invention will be described in detail. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not exceed the gist of the present invention.

[0029] In the present invention, “(meth)acrylic resin” means at least one selected from “acrylic resin” and “methacrylic resin”, “(meth)acrylic polymer” means at least one selected from “acrylic polymer” and “methacrylic polymer”, “(meth)acrylate” means at least one selected from “acrylate” and “methacrylate”, and “(meth)acrylic acid” means at least one selected from “acrylic acid” and “methacrylic acid”. The same applies to “(meth)acrylonitrile” and “(meth)acrylamide”.

[0030] In the present invention, “monomer” means an unpolymerized compound, and “structural unit derived from...” or “repeating unit” means a unit derived from the monomer formed by polymerization of the monomer. The repeating unit may be a unit directly formed by a polymerization reaction, or a unit in which a part of the unit is converted into another structure by treating a polymer. In this specification, “mass%” and “parts by mass” are synonymous with “weight%” and “parts by weight” respectively, and “mass%” indicates the content ratio of a predetermined component contained in 100 mass% of the total amount. Unless otherwise specified, the numerical range represented by “~” in this specification means a range including the numerical values described before and after “~” as the lower limit value and the upper limit value. For example, “A~B” means A or more and B or less.

[0031] <Resin composition> The resin composition according to one embodiment of the present invention is a resin composition containing acrylic rubber particles (A) containing a structural unit derived from an aromatic vinyl compound represented by the following formula (I). Hereinafter, the aromatic vinyl compound represented by the following formula (I) may be referred to as "aromatic vinyl compound (I)", and the structural unit derived from the aromatic vinyl compound (I) may be referred to as "aromatic vinyl compound (I) unit".

[0032]

Chemical formula

[0033] (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group.)

[0034] By including the acrylic rubber particles (A) containing the aromatic vinyl compound (I), the resin composition containing the acrylic rubber particles (A) and the resin molded article formed by molding the same can be chemically recycled with a small amount of impurities and excellent transparency. Furthermore, by containing the acrylic rubber particles (A), an excellent impact resistance improvement effect can also be obtained.

[0035] <Mechanism> Although the details of the mechanism by which the resin composition of the present invention exhibits the above effects are not clear, it is considered as follows. Usually, the acrylic rubber particles (A) often contain a structural unit derived from styrene as in Patent Document 1. When a resin composition or a resin molded article containing such acrylic rubber particles (A) is chemically recycled, it is presumed that, by thermal decomposition, the structural unit derived from styrene (i.e., the one in which R in the above formula (I) is a hydrogen atom) depolymerizes and many impurities are mixed into the monomer component after thermal decomposition. Among the impurities mixed in, toluene is particularly problematic. Therefore, in the present invention, by using the acrylic rubber particles (A) containing the aromatic vinyl compound (I) unit instead of the structural unit derived from styrene that generates toluene by depolymerization, the generation of toluene by depolymerization during chemical recycling is prevented, and a resin composition and a resin molded article having excellent recyclability and excellent transparency and impact resistance are obtained.

[0036] <Acrylic rubber particles (A)> The acrylic rubber particles (A) according to the present invention are characterized by including units of an aromatic vinyl compound (I). Acrylic rubber particles include a rubbery graft polymer containing an acrylic rubber part. This acrylic rubber part uses an elastomer of an acrylic resin and usually has a glass transition temperature of -10°C or lower.

[0037] The content of the units of the aromatic vinyl compound (I) in the acrylic rubber particles (A) according to the present invention is preferably 1.0% by mass or more, more preferably 5.0% by mass or more, and even more preferably 10.0% by mass or more based on the total amount of the acrylic rubber particles (A). If the content of the units of the aromatic vinyl compound (I) is at least the above lower limit, the effect of improving impact resistance by containing the units of the aromatic vinyl compound (I) is excellent. On the other hand, from the viewpoint of transparency, the content of the units of the aromatic vinyl compound (I) in the acrylic rubber particles (A) according to the present invention is preferably 30.0% by mass or less, more preferably 28.0% by mass or less, and even more preferably 25.0% by mass or less based on the total amount of the acrylic rubber particles (A).

[0038] In the present invention, the aromatic vinyl compound (I) may be any one represented by the aforementioned formula (I) and is not particularly limited. However, it is preferable that the substituent R in the formula (I) is substituted at the p-position or m-position with respect to the vinyl group from the viewpoint of obtaining a monomer with high purity even after chemical recycling. That is, the aromatic vinyl compound (I) is preferably represented by the following formula (Ia) or (Ib).

[0039]

Chemical formula

[0040] (In the formulas (Ia) and (Ib), R is the same as in the formula (I).)

[0041] Examples of such aromatic vinyl compounds (I) include m- or p-vinyltoluene, m- or p-vinylbenzylamine, 4-tert-butylstyrene, 4-ethylstyrene, 4-iso-propylstyrene, 4-n-butylstyrene, and the like. These aromatic vinyl compounds (I) may be used alone or in combination of two or more. Among these, m-vinyltoluene, p-vinyltoluene, or 4-tert-butylstyrene is preferred from the viewpoints of the impact resistance and transparency of the resin molded article.

[0042] The acrylic rubber particles (A) according to the present invention are usually particles having a two-layer structure or more. They may also be particles having a three-layer structure or more. In the case of particles having a multi-layer structure of two layers or more, from the viewpoint of the transparency of the resulting resin molded article, they contain an aromatic vinyl compound (I) unit as an essential component and at least one selected from a structural unit derived from methyl methacrylate (hereinafter sometimes referred to as "methyl methacrylate unit") and a structural unit derived from an alkyl (meth)acrylate other than methyl methacrylate (hereinafter sometimes referred to as "other alkyl (meth)acrylate unit"). It preferably has at least an inner layer (a) and a graft layer (b) containing a methyl methacrylate unit and having a multi-layer structure of two layers or more. More preferably, as the inner layer (a), it has an innermost layer (a-1) (hereinafter sometimes simply referred to as "inner layer (a-1)") and an intermediate layer (a-2), that is, it preferably has a multi-layer structure including the inner layer (a-1), the intermediate layer (a-2), and the graft layer (b).

[0043] Each layer in the multi-layer structure constitutes, for example, a two-layer structure of the inner layer (a) 1 and the graft layer (b) 2 of the outer layer from the center side as shown in Fig. 1(a), or a three-layer structure of the innermost layer (a-1) 1A, the intermediate layer (a-2) 1B, and the graft layer (b) 2 of the outer layer from the center side as shown in Fig. 1(b). Hereinafter, the polymer having this multi-layer structure will be described for each layer.

[0044] As the inner layer (a-1) in the acrylic rubber particles (A) according to the present invention, a crosslinked polymer containing 40.0 to 95.0% by mass, particularly 45.0 to 80.0% by mass of methyl methacrylate units, 1.0 to 60.0% by mass, particularly 5.0 to 50.0% by mass of other alkyl (meth)acrylate units, 0.01 to 10.0% by mass, particularly 1.0 to 7.0% by mass of aromatic vinyl compound (I) units, and 0.01 to 10.0% by mass, particularly 0.02 to 5.0% by mass of structural units derived from a copolymerizable crosslinkable monomer (hereinafter sometimes referred to as "polyfunctional monomer") (hereinafter sometimes referred to as "polyfunctional monomer unit") is preferable.

[0045] Such an inner layer (a-1) can be formed by polymerizing a monomer mixture containing an aromatic vinyl compound (I), other alkyl (meth)acrylates, and a copolymerizable crosslinkable monomer, and methyl methacrylate used as needed, so as to have the above monomer composition.

[0046] By setting the composition and content of the monomers constituting the inner layer (a-1) within the above ranges, excellent impact resistance and transparency can be obtained in the resin composition of the present invention. In particular, when the usage amount of an alkyl acrylate having 1 to 4 carbon atoms in the alkyl group in the above monomer mixture is 40% by mass or more, a resin composition having a higher degree of transparency can be obtained. Also, it is preferable that the content of the polyfunctional monomer used in the inner layer (a-1) is 0.01 to 10.0 parts by mass with respect to 100 parts by mass of the above monomer mixture in terms of the balance between impact resistance and transparency. Note that even if it consists of a single monomer, it is expediently referred to as a "monomer mixture".

[0047] Examples of alkyl (meth) acrylates other than methyl methacrylate used for the other alkyl (meth) acrylate units of the inner layer (a-1) include alkyl methacrylates having 2 to 4 carbon atoms in the alkyl group or alkyl acrylates having 1 to 8 carbon atoms in the alkyl group. From the viewpoint of the transparency of the resulting resin molded body, among these, examples of alkyl methacrylates having 2 to 4 carbon atoms in the alkyl group specifically include ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, etc., and these can be used alone or in combination of two or more.

[0048] In addition, examples of alkyl acrylates having 1 to 8 carbon atoms in the alkyl group used for the inner layer (a-1) specifically include methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, etc., and these can be used alone or in combination of two or more. Among these, it is preferable to use n-butyl acrylate.

[0049] The aromatic vinyl compound (I) used for the inner layer (a-1) is as described above.

[0050] Examples of the polyfunctional monomer used for the inner layer (a-1) specifically include ethylene glycol diacrylate, 1,3-butanediol diacrylate, allyl acrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, allyl methacrylate, triallyl cyanurate, diallyl maleate, divinylbenzene, diallyl phthalate, diallyl fumarate, triallyl trimellitate, etc., and these can be used alone or in combination of two or more. Among these, it is preferable to use 1,3-butanediol dimethacrylate and allyl methacrylate.

[0051] In the acrylic rubber particles (A) according to the present invention, the intermediate layer (a-2) is an elastic copolymer containing 60 to 99.8% by mass, particularly 70 to 90% by mass, of an alkyl (meth) acrylate unit, 0 to 39.8% by mass, particularly 5.0 to 30.0% by mass, of an aromatic vinyl compound (I) unit, and 0.2 to 10.0% by mass, particularly 0.5 to 5.0% by mass, of a copolymerizable crosslinkable monomer (polyfunctional monomer) unit. Such an intermediate layer (a-2) can be formed by polymerizing a monomer mixture containing an alkyl (meth) acrylate, an aromatic vinyl compound (I), and a polyfunctional monomer in the presence of the inner layer (a-1) so as to have the above monomer unit composition.

[0052] By setting the composition and content of the monomers constituting the intermediate layer (a-2) within the above ranges, the resin composition of the present invention can have excellent impact resistance. In particular, when the amount of the alkyl (meth) acrylate used in the monomer mixture is 70% by mass or more, a resin composition having high impact resistance can be obtained.

[0053] Examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group used for the intermediate layer (a-2) are the same as those exemplified as the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group that can be used for the inner layer (a-1) described above. These can be used alone or in combination of two or more. Among these specific examples, it is preferable to use n-butyl acrylate.

[0054] The aromatic vinyl compound (I) used for the intermediate layer (a-2) is as described above.

[0055] Examples of the polyfunctional monomer used for the intermediate layer (a-2) are the same as those exemplified as the polyfunctional monomer that can be used for the inner layer (a-1) described above. These can be used alone or in combination of two or more. Among these examples, it is preferable to use 1,3-butanediol dimethacrylate and allyl methacrylate.

[0056] In the graft layer (b) of the acrylic rubber particles (A) according to the present invention, the monomer component is polymerized in the presence of the polymer formed up to the intermediate layer (a-2) described above, that is, in the presence of the inner layer (a-1). In the presence of the inner layer (a-1) / intermediate layer (a-2) multilayer structure, a monomer mixture containing 70 to 100% by mass, particularly 80 to 99% by mass of methyl methacrylate units and 1 to 30% by mass, particularly 1 to 20% by mass of other alkyl (meth)acrylate units is polymerized to form a non-crosslinked hard polymer graft layer (b).

[0057] As the monomer constituting the graft layer (b), an aromatic vinyl compound (I) may be used in combination with the above monomers. The aromatic vinyl compound (I) used for the graft layer (b) is as described above.

[0058] By setting the composition and content of the monomers constituting the graft layer (b) within the above ranges, the resin composition of the present invention can have excellent impact resistance. In particular, when the amount of alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group in the monomer mixture is 70 to 100% by mass, a resin composition having high impact resistance can be obtained.

[0059] As the other alkyl (meth)acrylate used as the other alkyl (meth)acrylate unit of the graft layer (b), an alkyl methacrylate having 2 to 4 carbon atoms in the alkyl group or an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferable from the viewpoint of the transparency of the obtained resin molded article. These can be specifically exemplified by the same ones as those exemplified as the alkyl (meth)acrylate other than methyl methacrylate used for the inner layer (a-1) or the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and the preferable ones are the same.

[0060] Each monomer component for obtaining the inner layer (a-1), the intermediate layer (a-2), and the graft layer (b) may contain components other than the above monomers. Examples of such components include chain transfer agents such as alkyl mercaptans used to improve the compatibility, fluidity, and impact resistance with the (meth)acrylic polymer (X) that becomes the matrix resin in the polymerization of these monomer components, particularly in the polymerization of the monomer components for obtaining the acrylic rubber particles (A). Specific examples of the alkyl mercaptan include n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, etc. The amount of the chain transfer agent used can be, for example, 0.1 to 2 parts by mass with respect to 100 parts by mass of the monomer components used.

[0061] Also, when the polymer formed up to the inner layer (a) in the acrylic rubber particles (A) is 100 parts by mass, the graft layer (b) is preferably 30 to 100 parts by mass, more preferably 50 to 80 parts by mass. When the content of the graft layer (b) is 30 to 100 parts by mass when the polymer formed up to the inner layer (a) is 100 parts by mass, the impact resistance of the resin composition of the present invention becomes sufficient.

[0062] Also, the mass ratio (a-1) / (a-2) of the inner layer (a-1) and the intermediate layer (a-2) in the acrylic rubber particles (A) is preferably 10 / 90 to 90 / 10, more preferably 15 / 85 to 25 / 75. When the mass percentage of the inner layer (a-1) is 10 or more in the total mass of the inner layer (a-1) and the intermediate layer (a-2), whitening when an impact is applied to the molded body using the resin composition of the present invention is suppressed, and when it is 90 or less, the impact resistance of the resin composition becomes sufficient.

[0063] Here, the mass of each layer is calculated as the total mass of the monomer components constituting each layer.

[0064] When the acrylic rubber particles (A) according to the present invention have a two-layer multilayer structure having an inner layer (a) containing at least one selected from aromatic vinyl compound (I) units, methyl methacrylate units, and other alkyl (meth)acrylate units, and a graft layer (b) containing methyl methacrylate units, the inner layer (a) contains 70.0 to 90.0% by mass, particularly 75.0 to 85.0% by mass, of alkyl (meth)acrylate (total of methyl methacrylate and other alkyl (meth)acrylates) units, 10.0 to 30.0% by mass, particularly 15.0 to 25.0% by mass, of aromatic vinyl compound (I) units, and 0.01 to 10.0% by mass, particularly 0.02 to 5.0% by mass, of polyfunctional monomer units, and is a layer containing a crosslinked polymer, which is preferable from the viewpoints of impact resistance and transparency of the resin composition of the present invention.

[0065] As the alkyl (meth)acrylate used for the alkyl (meth)acrylate units containing methyl methacrylate in the inner layer (a), alkyl methacrylates having 1 to 4 carbon atoms in the alkyl group or alkyl acrylates having 1 to 8 carbon atoms in the alkyl group are preferable from the viewpoint of the transparency of the resulting resin molded body. Among these, specific examples of the alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, etc., and these can be used alone or in combination of two or more. In addition, specific examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group used for the inner layer (a) include methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, etc., and these can be used alone or in combination of two or more. Among these, it is preferable to use n-butyl acrylate.

[0066] The aromatic vinyl compound (I) used for the inner layer (a) is as described above. In addition, examples of the polyfunctional monomer used for the inner layer (a) include those exemplified as the polyfunctional monomer used for the inner layer (a-1) described above, and preferred ones are the same.

[0067] The two-layer acrylic rubber particles (A) can be formed as a non-crosslinked hard polymer graft layer (b) by polymerizing a monomer mixture containing 70 to 100% by mass, particularly 80 to 99% by mass, of methyl methacrylate units and 1 to 30% by mass, particularly 1 to 20% by mass, of other alkyl (meth)acrylate units in the presence of the polymer forming the inner layer (a) as in the case of the three-layer acrylic rubber particles (A). In the two-layer acrylic rubber particles (A), an aromatic vinyl compound (I) may be combined and used in addition to the above monomers as the monomers constituting the graft layer (b).

[0068] The monomer components for obtaining the inner layer (a) and the graft layer (b) may contain components other than the above monomers as in the case of the three-layer structure. Such components are the same as described above.

[0069] Examples of the method for producing the acrylic rubber particles (A) according to the present invention include a method in which latexes of polymers constituting each layer are sequentially obtained by emulsion polymerization of monomer components forming the structural units of the polymers of the above respective layers, and then recovered as a graft polymer having a multilayer structure. The emulsion polymerization can be carried out according to a known method.

[0070] As a polymerization initiator used for the polymerization reaction to form the polymer of each layer of the above acrylic rubber particles (A), for example, as a radical polymerization initiator, peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, hydrogen peroxide; azo compounds such as azobisisobutyronitrile; persulfate compounds such as potassium persulfate and ammonium persulfate; perchloric acid compounds; perboric acid compounds and the like can be mentioned. These may be used alone or in combination of two or more. These initiators such as peroxides are used as redox initiators in combination with reducing agents such as alkali metal salts of thiosulfuric acid such as sodium sulfite and sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, hydroxyacetone acid, and a complex of ferrous sulfate and disodium ethylenediaminetetraacetate. In particular, it is preferable to use a complex of ferrous sulfate and disodium ethylenediaminetetraacetate and sodium formaldehyde sulfoxylate from the viewpoint of the transparency of the resulting resin composition. The addition amount of these radical polymerization initiators can be appropriately selected depending on the type and blending ratio of the radical polymerization initiator and monomer components used. For example, it can be about 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer components.

[0071] In the emulsion polymerization of the monomer components constituting the polymer of each layer for obtaining the above acrylic rubber particles (A), any of anionic, cationic, and nonionic emulsifiers can be used, but an anionic emulsifier is particularly preferable. As anionic emulsifiers, specifically, carboxylates such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate, dipotassium alkenyl succinate, sulfate esters such as sodium lauryl sulfate, sulfonates such as sodium dioctyl sulfosuccinate, sodium alkylbenzene sulfonate, sodium alkyl diphenyl ether disulfonate, phosphate esters such as sodium polyoxyethylene alkyl ether phosphate, etc. can be mentioned. These may be used alone or in combination of two or more. In particular, it is preferable from the viewpoint of the transparency of the resin composition obtained by using phosphate esters such as sodium polyoxyethylene alkyl ether phosphate.

[0072] As a method for recovering a polymer having a multilayer structure from the above latex, various methods such as an acid coagulation method, a salt coagulation method, a freeze coagulation method, and a spray drying method can be used. Examples of the recovery agent used in the salt coagulation method include inorganic salts such as aluminum chloride, aluminum sulfate, sodium sulfate, magnesium sulfate, sodium nitrate, and calcium acetate. However, in order to suppress the coloring of the resin molded body obtained by molding the resin composition of the present invention containing the acrylic rubber particles (A) having a multilayer structure to be recovered, calcium acetate is particularly preferable, and these can be used as an aqueous solution.

[0073] The concentration of the recovery agent in the recovery agent aqueous solution is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass. If the concentration of the recovery agent in the recovery agent aqueous solution is 0.1% by mass or more, it is possible to stably recover the acrylic rubber particles (A). If the concentration is 20% by mass or less, a large amount of the recovery agent does not mix in the recovered acrylic rubber particles (A) having a multilayer structure, and in the molded body of the resin composition containing this, it is possible to suppress a decrease in performance such as an increase in coloring.

[0074] The recovered acrylic rubber particles (A) can be dried to obtain a powder. After drying the acrylic rubber particles (A) to obtain a powder, a lubricant such as fine silica particles can be added and mixed to suppress the blocking of the acrylic rubber particles (A) and improve the handleability.

[0075] The mass average particle diameter of the polymer of the inner layer (a) of the acrylic rubber particles (A) according to the present invention produced in this way is preferably 80 to 300 nm, particularly preferably 100 to 250 nm. If the mass average particle diameter of the polymer of the inner layer (a) is not less than the above lower limit, the resin molded body obtained has good impact resistance, and if it is not more than the above upper limit, the resin molded body obtained has good transparency. Further, the mass average particle diameter of the acrylic rubber particles (A) of the present invention formed with the inner layer (a) and the graft layer (b) is preferably 110 to 400 nm, particularly preferably 120 to 350 nm. If the mass average particle diameter of the acrylic rubber particles (A) is not less than the above lower limit, the resin molded body obtained has good impact resistance, and if it is not more than the above upper limit, the resin molded body obtained has good transparency. Here, the mass average particle diameters of the inner layer (a) and the acrylic rubber particles (A) are the values measured by the method described in the Examples section below.

[0076] When the acrylic rubber particles (A) according to the present invention are acrylic rubber particles (A) having a three-layer structure having an inner layer (a-1), an intermediate layer (a-2), and a graft layer (b), the mass average particle diameter of the polymer of the inner layer (a-1) is preferably 150 to 250 nm, particularly preferably 170 to 200 nm. If the mass average particle diameter of the inner layer (a-1) is not less than the above lower limit, the resin molded body obtained has good impact resistance, and if it is not more than the above upper limit, the resin molded body obtained has good transparency. Further, the mass average particle diameter of the polymer formed by further forming the intermediate layer (a-2) on the inner layer (a-1) is preferably 220 to 300 nm, particularly preferably 240 to 280 nm. If the mass average particle diameter of the polymer formed up to the intermediate layer (a-2) is not less than the above lower limit, the resin molded body obtained has good impact resistance, and if it is not more than the above upper limit, the resin molded body obtained has good transparency. Further, the mass average particle diameter of the acrylic rubber particles (A) of the present invention, which form the inner layer (a-1), the intermediate layer (a-2) and the graft layer (b), is preferably 240 to 400 nm, particularly preferably 260 to 320 nm. If the mass average particle diameter of the acrylic rubber particles (A) is at least the above lower limit, the impact resistance of the resulting resin molded body is good, and if it is at most the above upper limit, the transparency of the resulting resin molded body is good. Here, the mass average particle diameters of the inner layer (a-1), the acrylic rubber particles (A), etc. are the values measured by the method described in the Examples section below.

[0077] The content ratio of the acrylic rubber particles (A) in the resin composition of the present invention is not particularly limited with respect to the mass of the entire resin composition (100% by mass), but is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. On the other hand, the upper limit of the content ratio of the acrylic rubber particles (A) is not particularly limited, but is preferably 99% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. Alternatively, the content ratio of the acrylic rubber particles (A) in the total mass (100% by mass) of the resin composition of the present invention is preferably 1% by mass or more and 99% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 20% by mass or more and 70% by mass or less.

[0078] If the content ratio of the acrylic rubber particles (A) in the total mass (100% by mass) of the resin composition of the present invention is at least the above lower limit, the impact resistance of the resulting resin molded body can be enhanced, and if it is at most the above upper limit, the transparency, heat resistance, weather resistance, etc. of the resulting resin molded body, which are the inherent properties of the (meth)acrylic resin, tend to be sufficiently maintained.

[0079] <(meth)acrylic polymer (X)> The (meth)acrylic polymer (X) is preferably included as one of the components of the resin composition of the present invention.

[0080] As the (meth)acrylic polymer (X) according to the present invention, preferably, a homopolymer of methyl methacrylate or a methyl methacrylate copolymer containing 50% by mass or more and less than 100% by mass of methyl methacrylate units based on 100% by mass of the total mass of the (meth)acrylic polymer (X) can be used.

[0081] From the viewpoint of improving the mechanical strength or thermal decomposition resistance of the resulting resin molded body, the (meth)acrylic polymer (X) can be a copolymer containing 50% by mass or more and less than 100% by mass of methyl methacrylate units and more than 0% by mass and 50% by mass or less of other alkyl (meth)acrylate units. Here, as the other alkyl (meth)acrylate, those having 1 to 8 carbon atoms in the alkyl group are particularly preferable. As the copolymer, a copolymer containing 80% by mass or more and 99.5% by mass or less of methyl methacrylate units and 0.5% by mass or more and 20% by mass or less of other alkyl (meth)acrylate units is more preferable, and a copolymer containing 90% by mass or more and 98% by mass or less of methyl methacrylate units and 2% by mass or more and 10% by mass or less of other alkyl (meth)acrylate units is even more preferable. Alternatively, from the viewpoint of improving the transparency, heat resistance, and weather resistance of the resulting resin molded body, the (meth)acrylic polymer (X) may be a homopolymer of methyl methacrylate.

[0082] Examples of the other alkyl (meth)acrylate include the following a). a) (Meth)acrylate compounds other than methyl methacrylate, such as methyl acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, norbornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tetracyclododecanyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, 2-(meth)acryloyloxymethyl-2-methylbicycloheptane, 4-(meth)acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane;

[0083] These other alkyl (meth)acrylates may be used alone or in combination of two or more. Among the other alkyl (meth)acrylates, methyl acrylate, ethyl acrylate, and n-butyl acrylate are more preferable, and methyl acrylate and ethyl acrylate are even more preferable because they hardly impair the original performance of the (meth)acrylic resin and the resulting resin molded article has good thermal decomposition resistance, weather resistance, and heat moldability.

[0084] The (meth)acrylic polymer (X) according to the present invention may contain structural units derived from other monomers copolymerizable with these, other than methyl methacrylate units and other alkyl (meth)acrylate units, in a proportion of 30% by mass or less in the (meth)acrylic polymer (X) as long as the original properties of the (meth)acrylic polymer (X) are not impaired. The other monomers are not particularly limited as long as they are monomers copolymerizable with methyl methacrylate, and examples thereof include the following b) to J). These may be used alone or in combination of two or more. b) (Meth)acrylic acid; c) (Meth)acrylonitrile; d) (Meth)acrylamide compounds such as (meth)acrylamide, N-dimethyl(meth)acrylamide, N-diethyl(meth)acrylamide, N-butyl(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, and methylenebis(meth)acrylamide; e) Aromatic vinyl compounds such as styrene and α-methylstyrene; f) Vinyl ether compounds such as vinyl methyl ether, vinyl ethyl ether, and 2-hydroxyethyl vinyl ether; g) Vinyl carboxylate compounds such as vinyl acetate and vinyl butyrate; h) Olefin compounds such as ethylene, propylene, butene, and isobutene; i) Unsaturated dicarboxylic acid anhydrides such as maleic anhydride; J) Maleimide compounds such as cyclohexyl maleimide and phenyl maleimide:

[0085] Although the lower limit of the content ratio of the (meth)acrylic polymer (X) contained in the total mass (100% by mass) of the resin composition of the present invention is not particularly limited, it is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. On the other hand, the upper limit of the content ratio of the (meth)acrylic polymer (X) is not particularly limited, but is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less. Alternatively, the content ratio of the (meth)acrylic polymer (X) in the total mass (100% by mass) of the resin composition of the present invention is preferably 1% by mass or more and 99% by mass or less, more preferably 10% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less.

[0086] If the content ratio of the (meth)acrylic polymer (X) in the total mass (100% by mass) of the resin composition of the present invention is equal to or higher than the lower limit value, the resulting resin molded article can sufficiently obtain the original properties of the (meth)acrylic resin such as heat resistance and weather resistance. If it is equal to or lower than the upper limit value, the content of the acrylic rubber particles (A) can be ensured, and the resulting resin molded article tends to have excellent impact resistance.

[0087] The method for producing the (meth)acrylic polymer (X) is not particularly limited, and examples thereof include bulk polymerization method, suspension polymerization method, emulsion polymerization method, solution polymerization method, etc. Among these polymerization methods, from the viewpoint of excellent productivity, the (meth)acrylic polymer (X) is preferably produced by the bulk polymerization method or the suspension polymerization method, and more preferably produced by bulk polymerization.

[0088] The mass average molecular weight of the (meth)acrylic polymer (X) is preferably 20,000 to 200,000, and more preferably 50,000 to 150,000. When the mass average molecular weight of the (meth)acrylic polymer (X) is equal to or higher than the lower limit value, the resulting resin molded article tends to have excellent mechanical properties. When it is equal to or lower than the upper limit value, it tends to have excellent fluidity during melt molding.

[0089] In addition, in this specification, the mass average molecular weight of the (meth)acrylic polymer (X) shall be the value measured using gel permeation chromatography with standard polystyrene as the standard sample.

[0090] <Other resin components> The acrylic rubber particles (A) according to the present invention are preferably used in the resin composition of the present invention when blended with the above-mentioned (meth)acrylic polymer (X). In addition, other olefin resins such as polypropylene (PP) and polyethylene (PE); polystyrene (PS), high impact polystyrene (HIPS), (meth)acrylate-styrene copolymer (MS), styrene-acrylonitrile copolymer (SAN), styrene-maleic anhydride copolymer (SMA), acrylonitrile-butadiene-styrene copolymer (ABS), acrylate ester-styrene-acrylonitrile copolymer (ASA), acrylonitrile-ethylene-propylene rubber-styrene copolymer (AES), etc. Styrene (St) resins; PC resins; polyamide (PA) resins; PEs resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); (modified) polyphenylene ether ((m-)PPE) resins, polyoxymethylene (POM) resins, polysulfone (PSO) resins, polyarylate (PAr) resins, polyphenylene (PPS) resins, etc. Engineering plastics; thermoplastic polyurethane (PU) resins; alloys of PC resins and St resins such as PC / ABS, alloys of PVC resins and St resins such as PVC / ABS, alloys of PA resins and St resins such as PA / ABS, alloys of PA resins and TPEs, alloys of PA resins and polyolefin resins such as PA / PP, alloys of PC resins and PEs resins such as PC / PBT, polyolefin resins / TPEs, alloys of olefin resins such as PP / PE, alloys of PPE resins such as PPE / HIPS, PPE / PBT, PPE / PA, etc. Polymer alloys; thermoplastic resins such as rigid vinyl chloride resins, semi-rigid vinyl chloride resins, flexible vinyl chloride resins, etc. PVC resins, and styrene-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, fluorine-based elastomers, 1,2-polybutadiene, trans 1,4-polyisoprene, etc. It can also be blended with thermoplastic elastomers. That is, the resin composition of the present invention may contain the acrylic rubber particles (A) according to the present invention and the other resin components described above, or may contain the acrylic rubber particles (A) according to the present invention, the (meth)acrylic polymer (X), and other resin components.

[0091] <Other components> The resin composition of the present invention can contain other components other than the above acrylic rubber particles (A) and the aforementioned (meth)acrylic polymer (X) within a range that does not impair the object of the present invention. Examples of other components that the resin composition of the present invention can contain include antioxidants, ultraviolet absorbers, light stabilizers, mold release agents, pigments, dyes, and the like. These other components are usually preferably contained in the resin composition of the present invention in a range of 5.0% by mass or less.

[0092] <Method for producing resin composition> The resin composition of the present invention can be produced by blending the above-described acrylic rubber particles (A) and preferably further the aforementioned (meth)acrylic polymer (X) and other components used as necessary at a predetermined blending ratio.

[0093] <Recyclability: Toluene detection amount in pyrolysis GC-MS measurement> From the viewpoint of reducing the amount of impurities contained in methyl methacrylate recovered after the chemical recycling process, the amount of toluene detected when GC-MS measurement is performed using a Restek column Rtx1701 at a furnace temperature of 370°C and a heating time of 3 minutes is preferably 100 mass ppm or less, more preferably 80 mass ppm or less, still more preferably 60 mass ppm or less, and particularly preferably 30 mass ppm or less with respect to the entire resin composition.

[0094] Since the detected amount of toluene is small, even if the resin composition and resin molded article of the present invention undergo processes such as pyrolysis in subsequent chemical recycling processes, thereafter, impurities such as toluene, which may pose a problem of being mixed into the recovered recycled methyl methacrylate, are in small amounts, and the resulting recycled product has high purity. The recycled methyl methacrylate, the resin composition polymerized therefrom, and the resin molded article have excellent transparency. Specifically, the detected amount of toluene is measured by the method described in the Examples section below.

[0095] [Resin Molded Article] The resin molded article of the present invention is obtained by molding the resin composition of the present invention.

[0096] The resin molded article of the present invention is not particularly limited as long as it is molded by a known molding method, for example, press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, hollow molding, multi-layer molding, melt spinning, etc. However, from the viewpoint of moldability, the resin composition of the present invention is suitable as a resin composition for injection molding.

[0097] Specific examples of the resin molded article of the present invention include vehicle parts such as exterior and interior materials of vehicles such as tail lamp covers, head lamp covers, inner lenses, meter panels, pillar garnishes, front grills, emblems; optical members such as lenses and light guides; building parts; parts for housing equipment such as washbasin vanities, bathtubs, and flush toilets; containers for cosmetics and foods; medical parts such as cuvettes; building materials; toys, and the like. Among these, in particular, the resin molded article of the present invention is preferably used for vehicle members, optical members, food containers, cosmetic containers, medical parts, communication equipment, films, building materials, and toys due to its excellent appearance, impact resistance, weather resistance, transparency, chemical resistance, and recyclability, and is particularly suitable as vehicle members and optical members.

Examples

[0098] Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples, and Reference Examples. The present invention is not limited to these Examples. In addition, in this Example, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified. The abbreviations, various measurement and evaluation methods in Examples, Comparative Examples, and Reference Examples are as follows.

[0099] [Abbreviations] SFS: Sodium formaldehyde sulfoxylate VT: Vinyltoluene 4-TBS: 4-tert-butylstyrene BA: n-butyl acrylate AMA: Allyl methacrylate TBHP: t-butyl hydroperoxide MMA: Methyl methacrylate nOM: n-octyl mercaptan MA: Methyl acrylate RS-610NA: Polyoxyethylene alkyl ether phosphate salt: Phosphanol RS-610NA, trade name, manufactured by Toho Chemical Co., Ltd. (Meth)acrylic polymer (X-1): Acrypet (registered trademark) VH (manufactured by Mitsubishi Chemical Corporation, mass average molecular weight: 80,000)

[0100] [Measurement and Evaluation Methods] [Mass average particle diameter of acrylic rubber particles (A)] The mass average particle diameter of acrylic rubber particles (A) was measured as follows. The obtained latex was diluted with distilled water to obtain a diluted latex with a solid content concentration of about 3%. 0.1 mL of this was used as a sample, and using a CHDF2000 particle size distribution measuring device manufactured by MATEC, USA, the measurement was carried out under the conditions of a flow rate of 1.4 mL / min, a pressure of about 2.76 MPa (about 4000 psi), and a temperature of 35°C. In the measurement, a capillary cartridge for particle separation and a carrier liquid were used, and the liquid property was made almost neutral. Before the measurement, using monodisperse polystyrene with a known particle diameter manufactured by DUKE, USA, as a standard particle diameter substance, a total of 12 particle diameters from 20 nm to 800 nm were measured to create a calibration curve.

[0101] <Preparation of test pieces for evaluation> (Preparation of resin molded body X1) The resin compositions obtained in the examples, comparative examples, and reference examples were dried with hot air at 80°C for about 4 hours, and then using an injection molding machine (model name: EC75SXIII - 2A, manufactured by Toshiba Machine Co., Ltd.), injection molding was carried out under the conditions of a molding temperature of 250°C and a mold temperature of 60°C to obtain test pieces (Charpy impact test molded pieces) of resin molded body X1 with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. (Preparation of resin molded body X2) The resin compositions obtained in the examples, comparative examples, and reference examples were dried with hot air at 80°C for about 4 hours, and then using an injection molding machine (model name: EC20PN - II, manufactured by Toshiba Machine Co., Ltd.), injection molding was carried out under the conditions of a molding temperature of 250°C and a mold temperature of 60°C to obtain test pieces of resin molded body X2 with a length of 50 mm, a width of 50 mm, and a thickness of 3 mm.

[0102] <Transparency: Haze> As an index of transparency, using a haze meter (model name: NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.), in accordance with ISO 14782, the haze value (%) of resin molded body X2 was measured. For the determination, if it was 10.0% or less, it was marked as "○", and if it exceeded 10.0%, it was marked as "×".

[0103] <Impact resistance: Charpy impact strength> As an index of impact resistance, using a digital impact tester (model name: DG-UB, manufactured by Toyo Seiki Seisakusho), in accordance with ISO 179-1, under the condition of a temperature of 23°C, the notched Charpy impact strength (kJ / m 2 ) of the resin molded body X1 was measured. The greater the Charpy impact strength, the better the impact resistance. As a judgment, if it is 2.0 kJ / m 2 or more, it is marked as "○", and if it is less than 2.0 kJ / m 2 , it is marked as "×".

[0104] <Recyclability: Quantification of Toluene in Pyrolysis GC-MS Measurement> When the resin composition sample was put into the pyrolysis apparatus set under the following conditions, the gas generated was cooled and trapped at the tip of the GC column for 3 minutes using a microjet cryotrap apparatus manufactured by Frontier Lab. After the cooling stopped, the trapped components were rapidly thermally desorbed by the heat of the GC oven and GC-MS measurement was started. The area value of the peak derived from toluene appearing on the pyrogram was obtained, and the toluene in the pyrolysis gas was quantified by comparing this area value with the calibration curve. The calibration curve was created using a standard solution prepared by adding a known amount (concentration) of toluene to acetone. (Pyrolysis) Pyrolysis apparatus: "PY-3030D" manufactured by Frontier Lab Furnace temperature: 370°C Interface temperature: 320°C Heating time: 3 minutes Microjet cryotrap: MJT-2030E manufactured by Frontier Lab Sample amount: 0.35 ± 0.02 mg Atmosphere gas during pyrolysis: Helium (GC-MS) GC-MS analyzer: "GC7890" manufactured by Agilent / "MS5975" manufactured by Agilent Separation column: "Rtx1701 (length 30 m, inner diameter 0.25 mm, film thickness 1.0 μm) manufactured by Restek Carrier gas: Helium Inlet temperature: 260°C Column temperature: 40 °C (held for 10 minutes) - heated at 10 °C / min - 260 °C (held for 10 minutes) Split mode: 50:1 Average linear velocity: 39.723 cm / s (constant flow mode) Ionization method: EI Ion source temperature: 230 °C MS scan range: 20 - 400 amu As a judgment, if the concentration of toluene is 100 ppm or less, it is marked as "○", and if it exceeds 100 ppm, it is marked as "×".

[0105] [Production Example 1: Production of acrylic rubber particles (A-1)] The following Component 1 was placed in a five-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer addition port, and a thermometer. (Component 1) Deionized water 240 parts RS-610NA 0.16 part Sodium carbonate 0.032 part

[0106] Next, while stirring and mixing the system and purging with nitrogen, the temperature was raised to 80 °C, and the following Component 2 was added. (Component 2) Ferrous sulfate 1.2×10 -3 parts Disodium ethylenediaminetetraacetate 3.6×10 -3 parts SFS 0.43 part

[0107] After 5 minutes, the mixture (a) with the following composition for the inner layer (a) was added over 2 hours and held at 80 °C for 1 hour to complete the polymerization of the polymer of the inner layer (a). The polymerization rate of the obtained latex (D) (unreacted monomers were measured by gas chromatography, the same applies hereinafter) was 99% or more, and the mass average particle diameter of the polymer for the inner layer (a) was 110 nm. (Mixture (a)) BA 81.5 parts VT 18.5 parts AMA 0.9 part TBHP 0.3 part RS-610NA 1.6 parts

[0108] Subsequently, a solution prepared by dissolving 0.12 part of SFS in 3.0 parts of deionized water was added to the above latex (D), and after holding for 15 minutes, a mixture (b) having the following composition for the graft layer (b) was added dropwise over 90 minutes and held for 1 hour to complete the polymerization of the polymer of the graft layer (b). The polymerization rate of the obtained final latex (E) was 99% or more. (Mixture (b)) 57.0 parts of MMA 3.0 parts of MA 0.4 part of TBHP 0.18 part of nOM

[0109] Subsequently, 300 parts of a 1.3% aqueous calcium acetate solution as a recovery agent aqueous solution was charged into a stainless steel container, and the temperature was raised to 80°C with mixing and stirring, and 300 parts of the above latex (E) was continuously added over 10 minutes. Then, the temperature was raised to 92°C and held for 5 minutes. After cooling to room temperature, it was filtered by centrifugal dehydration (1300G, 3 minutes) while washing with deionized water to obtain a wet resin, and dried at 75°C for 48 hours to obtain white powdery acrylic rubber particles (A-1). The mass average particle diameter of the acrylic rubber particles (A-1) was 125 nm.

[0110] [Production Examples 2 to 6: Production of Acrylic Rubber Particles (A-2) to (A-6)] As shown in Table 1, acrylic rubber particles (A-2) to acrylic rubber particles (A-6) having the mass average particle diameters shown in Table 1 were obtained in the same manner as in Production Example 1 except that the types and compositions of the raw materials were changed.

[0111]

Table 1

[0112] [Example 1] 60 parts by mass of a (meth)acrylic polymer (X-1) and 40 parts by mass of acrylic rubber particles (A-1) were blended and supplied to a twin-screw extruder (model name "PCM30", L / D = 25, manufactured by Ikegai Corporation), and kneaded at a barrel temperature of 250 °C, a die temperature of 250 °C, and a screw rotation speed of 250 rpm to obtain a pelletized resin composition. The evaluation results of the obtained resin composition are shown in Table 1.

[0113] [Examples 2 to 4, Comparative Examples 1 and 2] A resin composition was obtained in the same manner as in Example 1 except that the compounding composition shown in Table 2 was used. The evaluation results of the obtained resin composition are shown in Table 2.

[0114] [Reference Example 1] Various evaluations were carried out using only the (meth)acrylic polymer (X-1), and the results are shown in Table 2.

[0115]

Table 2

[0116] From the results shown in Table 2, the resin compositions of Examples 1 to 4 and the resin molded articles formed therefrom contain acrylic rubber particles (A) containing aromatic vinyl compound (I) units, and thus have excellent impact resistance and transparency, and the amount of toluene, an impurity mixed in after the pyrolysis GC-MS evaluation, is small, and it was confirmed that they are excellent in recyclability.

[0117] The resin composition of Comparative Example 1 and the resin molded article formed therefrom used acrylic rubber particles (A-5) containing a structural unit derived from styrene instead of the aromatic vinyl compound (I) unit. Therefore, while having excellent impact resistance and transparency, it was confirmed that the amount of toluene among the impurities mixed in after the pyrolysis GC-MS evaluation is large and the recyclability is insufficient.

[0118] The resin composition of Comparative Example 2 and the resin molded article formed by molding the same use acrylic rubber particles (A-6) that do not contain an aromatic vinyl compound (I) unit or a structural unit derived from styrene. They are excellent in impact resistance, have a small amount of toluene as an impurity mixed in after the decomposition GC-MS evaluation, and are excellent in recyclability. On the other hand, it was confirmed that the transparency is insufficient.

[0119] Since the resin composition of Reference Example 1 and the resin molded article formed by molding the same do not contain acrylic rubber particles (A) themselves, they are excellent in transparency, have a small amount of toluene as an impurity mixed in after the thermal decomposition GC-MS evaluation, and are excellent in recyclability. On the other hand, it was confirmed that the impact resistance is insufficient.

Explanation of symbols

[0120] 1 Inner layer (a) 1A Innermost layer (a-1) 1B Intermediate layer (a-2) 2 Graft layer (b)

Claims

1. A resin composition comprising acrylic rubber particles (A) containing a structural unit derived from an aromatic vinyl compound represented by the following formula (I). 【Chemical 1】 (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group.)

2. The resin composition according to claim 1, wherein the acrylic rubber particles (A) are particles having a two-layer structure or more.

3. The resin composition according to claim 2, wherein the acrylic rubber particles (A) are particles having a three-layer structure.

4. The resin composition according to claim 1, comprising a (meth)acrylic polymer (X) in the resin composition.

5. The resin composition according to claim 4, wherein the content of the (meth)acrylic polymer (X) is 50% by mass or more based on the resin composition.

6. The resin composition according to claim 4, wherein the content ratio of the repeating unit derived from methyl methacrylate in the (meth)acrylic polymer (X) is 50% by mass or more.

7. The resin composition according to claim 1, wherein the content of the structural unit derived from the aromatic vinyl compound represented by the formula (I) is 1.0% by mass or more and 30.0% by mass or less based on the whole acrylic rubber particles (A).

8. The resin composition according to claim 1, wherein the aromatic vinyl compound represented by the formula (I) is one or more selected from the group consisting of m-vinyltoluene, p-vinyltoluene, and 4-tert-butylstyrene.

9. When GC-MS measurement is performed using a column Rtx1701 manufactured by Restek at a furnace temperature of 370 ° C and a heating time of 3 minutes, the amount of toluene detected is 100 mass ppm or less based on the whole resin composition. The resin composition according to claim 1.

10. The resin composition according to claim 1, which is a resin composition for recycling.

11. A resin molded article formed by molding the resin composition according to any one of claims 1 to 10.

12. A vehicle member formed by molding the resin composition according to any one of claims 1 to 10.

13. An optical member formed by molding the resin composition according to any one of claims 1 to 10.

14. A cosmetic container formed by molding the resin composition according to any one of claims 1 to 10.

15. A food container formed by molding the resin composition according to any one of claims 1 to 10.

16. A film formed by molding the resin composition according to any one of claims 1 to 10.

17. A toy formed by molding the resin composition according to any one of claims 1 to 10.

18. A building material formed by molding the resin composition according to any one of claims 1 to 10.

19. A communication equipment formed by molding the resin composition according to any one of claims 1 to 10.

20. A method for manufacturing a resin molded body, which manufactures a resin molded body by molding a resin composition containing acrylic rubber particles (A) containing a structural unit derived from an aromatic vinyl compound represented by the following formula (I). 【Chemical 2】 (In formula (I), R represents a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, or an aminomethyl group.)

21. The method for manufacturing a resin molded body according to claim 20, wherein the molding is injection molding.

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