Transparent thermoplastic resin composition, molded article obtained therefrom, and method for producing transparent thermoplastic resin composition

Abstract

An object of the present invention is to provide a transparent thermoplastic resin composition having excellent transparency and fluidity while maintaining high transparency, and a molded article thereof. The gist of the present invention for solving this problem is a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2), and a vinyl cyanide monomer (b3), the following ester compound (C), and the following ester compound (D). Ester compound (C): A hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid, and 85% by mass or more of the acids constituting the triglyceride is a hydrogenated product of ricinoleic acid. Ester compound (D): An ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid.

Description

Technical Field

[0001] The present invention relates to a transparent thermoplastic resin composition and a molded article thereof.

Background Art

[0002] A transparent ABS (Acrylonitrile Butadiene Styrene) resin containing a graft copolymer obtained by copolymerizing a rubbery polymer such as a diene rubber with an aromatic vinyl compound such as styrene or α-methylstyrene, a vinyl cyanide compound such as acrylonitrile or methacrylonitrile, and an unsaturated carboxylic acid alkyl ester compound such as methyl methacrylate or methyl acrylate is excellent in mechanical strength balance such as transparency, impact resistance, and rigidity, moldability due to fluidity, and cost performance. Therefore, it is widely used in applications such as home appliances, communication-related equipment, general sundries, and medical equipment. And attempts to further improve its impact resistance and fluidity have been continued.

[0003] As documents disclosing resin compositions containing hydrogenated castor oil, the following documents are known. For example, in Patent Document 1, there is a rubber-modified styrene-based resin composition containing (I) 60 to 80% by mass of a continuous phase of a styrene-(meth)acrylate copolymer, which is a copolymer of a styrene-based monomer, a (meth)acrylate-based monomer, and, if necessary, a vinyl-based monomer copolymerizable with these monomers, and (II) 40 to 20% by mass of a dispersed phase of a graft copolymer obtained by grafting a styrene-(meth)acrylate copolymer, which is a copolymer of a styrene-based monomer, a (meth)acrylate-based monomer, and, if necessary, a vinyl-based monomer copolymerizable with these monomers, onto a rubber-like elastomer. The volume average particle diameter of the dispersed phase is 0.3 to 0.6 μm, and specific ranges of values used in a specific calculation formula among the weight average molecular weight (Mw) of the continuous phase, the (meth)acrylate-based monomer unit, and the styrene-based monomer unit are defined. Also, 0.005 to 0.05 parts by mass of an organopolysiloxane is contained per 100 parts by mass of the resin composition. Further, 0.1 to 2.5 parts by mass of an ester-based lubricant is contained per 100 parts by mass of the rubber-modified styrene-based resin composition, and the ester-based lubricant is hydrogenated castor oil, and a thermoplastic resin composition is described.

[0004] In addition, the following documents are known as documents disclosing resin compositions containing hydrogenated castor oil and fatty acid esters. For example, Patent Document 2 discloses a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2) and a vinyl cyanide monomer (b3), an ester wax (C): hydrogenated castor oil, and an ester wax (D): a fatty acid ester composed of a linear saturated monocarboxylic acid having 12 to 30 carbon atoms and at least one alcohol selected from the group consisting of a linear saturated monohydric alcohol having 14 to 30 carbon atoms and a polyhydric alcohol having 2 to 6 hydroxyl groups and 2 to 30 carbon atoms, and a transparent thermoplastic resin composition containing the same is proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, conventional thermoplastic resin compositions cannot have high levels of transparency, impact resistance, and fluidity, and further improvement has been demanded.

[0007] An object of the present invention is to solve the problems in the above-described conventional technologies, and to provide a transparent thermoplastic resin composition and a molded article thereof that have transparency, impact resistance, and fluidity, that is, that have excellent impact resistance and fluidity while maintaining particularly high transparency.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the present inventors have found that a resin composition containing a vinyl copolymer obtained by copolymerizing a vinyl monomer mixture, a rubber-containing graft copolymer, and two specific additives has excellent impact resistance and fluidity while maintaining particularly high transparency, and thus have reached the present invention. That is, the present invention is characterized by the following (1) to (9). (1) A graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2), and a vinyl cyanide monomer (b3), the following ester compound (C), and the following ester compound (D). Ester compound (C): A hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid, and 85% by mass or more of the acids constituting the triglyceride is a hydrogenated product of ricinoleic acid. Ester compound (D): An ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid. (2) The transparent thermoplastic resin composition according to (1) above, wherein the hydroxyl value of the ester compound (D) is 170 to 350 mgKOH / g. (3) The content of the ester compound (C) is 0.4 to 0.8 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl-based copolymer (B), and the content of the ester compound (D) is 0.6 to 2.4 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl-based copolymer (B), and the mass ratio of the ester compound (C) to the ester compound (D) ((C):(D)) is 25:75 to 40:60. The transparent thermoplastic resin composition according to (1) or (2). (4) The weight-average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition is 100,000 to 120,000. The transparent thermoplastic resin composition according to any one of (1) to (3). (5) In the acetone-soluble component contained in the transparent thermoplastic resin composition, when the total of the structural units derived from (meth)acrylate monomers, the structural units derived from aromatic vinyl monomers, the structural units derived from vinyl cyanide monomers, and the structural units derived from other vinyl monomers is 100% by mass, the content of the structural units derived from (meth)acrylate monomers is 50 to 82% by mass, the content of the structural units derived from aromatic vinyl monomers is 10 to 30% by mass, and the content of the structural units derived from vinyl cyanide monomers is 8 to 15% by mass. The transparent thermoplastic resin composition according to any one of (1) to (4). (6) In the acetone-soluble component contained in the transparent thermoplastic resin composition, when the weight-average molecular weight of the acetone-soluble component is Mw1 and the content (mass%) of the structural units derived from vinyl cyanide monomers when the mass of the acetone-soluble component is 100% by mass is W1, the value obtained by dividing Mw1 by W1 is 11,000 or more. The transparent thermoplastic resin composition according to any one of (1) to (5). (7) The transparent thermoplastic resin composition further contains polydimethylsiloxane gum (E). The transparent thermoplastic resin composition according to any one of (1) to (6). Step of obtaining a graft copolymer (A) by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), step of obtaining a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2) and a vinyl cyanide monomer (b3), and a step of blending the graft copolymer (A), the vinyl copolymer (B), the following ester compound (C) and the following ester compound (D). A method for producing a transparent thermoplastic resin composition. Ester compound (C): A hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid and dihydroxystearic acid, and 85% by mass or more of the acids constituting the triglyceride is ricinoleic acid. Ester compound (D): An ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid. (9) A molded article molded using the transparent thermoplastic resin composition according to any one of (1) to (7). (10) A molded article molded using the transparent thermoplastic resin composition obtained by the production method according to (8). [Advantages of the Invention]

[0009] According to the present invention, a transparent thermoplastic resin composition having excellent impact resistance and fluidity while maintaining particularly high transparency can be obtained. [Brief Description of the Drawings]

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail, but these show an example of a desirable embodiment, and the present invention is not limited to these contents.

[0012] In the present specification, “(meth)acrylic acid” represents both acrylic acid and methacrylic acid. For example, methyl (meth)acrylate includes both methyl acrylate and methyl methacrylate.

[0013] The transparent thermoplastic resin composition of the present invention contains a graft copolymer (A), a vinyl copolymer (B), and two specific additives (ester compound (C), ester compound (D)) described later. By containing the graft copolymer (A), the moldability of the transparent thermoplastic resin composition can be improved, and the impact resistance and transparency of the molded article can be improved. Further, by containing the vinyl copolymer (B), the fluidity of the transparent thermoplastic resin composition can be improved, and the transparency of the molded article can be improved. And by containing two specific additives, the impact resistance of the molded article can be improved without lowering the transparency of the molded article, and the fluidity of the transparent thermoplastic resin composition can be improved to obtain good moldability.

[0014] (Graft copolymer (A)) The graft copolymer (A) constituting the transparent thermoplastic resin composition of the present invention is obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r). The monomer mixture (a) may further contain another monomer (a3) copolymerizable with the (a1) and the (a2).

[0015] Examples of the rubbery polymer (r) include polybutadiene, poly(butadiene-styrene) (SBR), poly(butadiene-acrylonitrile) (NBR), poly(butadiene-butyl acrylate), poly(butadiene-methyl methacrylate), poly(butyl acrylate-methyl methacrylate), poly(butadiene-ethyl acrylate), natural rubber, and the like. These may be used alone or in combination of two or more. Among them, from the viewpoint of further improving the impact resistance and transparency of the molded article, polybutadiene, SBR, NBR, and natural rubber are preferred, and polybutadiene is more preferred.

[0016] The mass average particle diameter of the rubbery polymer (r) is preferably 0.15 to 0.4 μm, more preferably 0.20 to 0.35 μm, and still more preferably 0.25 to 0.35 μm. When the mass average particle diameter of the rubbery polymer (r) is less than 0.15 μm, the impact resistance of the molded article may decrease. On the other hand, when the mass average particle diameter of the rubbery polymer (r) exceeds 0.4 μm, the transparency of the molded article may decrease.

[0017] The mass average particle diameter of the rubbery polymer (r) can be calculated from the particle size distribution measured by diluting and dispersing the latex of the rubbery polymer (r) in an aqueous medium using a laser scattering diffraction method particle size distribution measuring device (for example, "LS 13 320" (Beckman Coulter, Inc.)).

[0018] When the total amount of the rubbery polymer (r) and the monomer mixture (a) constituting the graft copolymer (A) is 100% by mass, the content of the rubbery polymer (r) is preferably 20 to 80% by mass. When the content of the rubbery polymer (r) is 20% by mass or more, the impact resistance and transparency of the molded article can be further improved. The content of the rubbery polymer (r) is more preferably 35% by mass or more. On the other hand, when the content of the rubbery polymer (r) is 80% by mass or less, the fluidity of the transparent thermoplastic resin composition and the impact resistance of the molded article can be further improved. The content of the rubbery polymer (r) is more preferably 60% by mass or less.

[0019] Examples of the aromatic vinyl monomer (a1) include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, vinyltoluene, and t-butylstyrene. These may be used alone or in combination of two or more. Among these, from the viewpoint of further improving the fluidity of the transparent thermoplastic resin composition and the transparency and rigidity of the molded article, it is preferable to use styrene.

[0020] From the viewpoint of further improving the fluidity of the transparent thermoplastic resin composition and the transparency and rigidity of the molded article, when the mass of the monomer mixture (a) is 100% by mass, the content of the aromatic vinyl monomer (a1) in the monomer mixture (a) is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more. On the other hand, from the viewpoint of improving the impact resistance and transparency of the molded article, the content of the aromatic vinyl monomer (a1) in the monomer mixture (a) is preferably 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less. When the content of the aromatic vinyl monomer (a1) is within the above range, when the total of the structural units derived from (meth)acrylate monomers, the structural units derived from aromatic vinyl monomers, the structural units derived from vinyl cyanide monomers, and the structural units derived from other vinyl monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below is 100% by mass, a transparent thermoplastic resin composition in which the content of the structural units derived from aromatic vinyl monomers is 10 to 30% by mass can be easily produced.

[0021] As the (meth)acrylic acid ester monomer (a2) in the monomer mixture (a), for example, esters of alcohols having 1 to 6 carbon atoms and acrylic acid or methacrylic acid are preferable. The esters of alcohols having 1 to 6 carbon atoms and acrylic acid or methacrylic acid may further have substituents such as a hydroxyl group or a halogen group. Examples of the esters of alcohols having 1 to 6 carbon atoms and acrylic acid or methacrylic acid include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, chloromethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth)acrylate, 2,3,4,5-tetrahydroxypentyl (meth)acrylate, and the like. These may be used alone or in combination of two or more. Among these, from the viewpoint of improving the transparency of the molded article, methyl (meth)acrylate is preferable.

[0022] From the viewpoint of improving the transparency of the molded article, the content of the (meth)acrylic acid ester monomer (a2) in the monomer mixture (a) is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 60% by mass or more in 100% by mass of the total monomer mixture (a). On the other hand, from the viewpoint of improving the transparency of the molded article, the content of the (meth)acrylic acid ester monomer (a2) in the monomer mixture (a) is preferably 82% by mass or less, more preferably 80% by mass or less, and still more preferably 75% by mass or less in 100% by mass of the total monomer mixture (a). When the content of the (meth)acrylic acid ester monomer (a2) is within the above range, when the total of the structural units derived from the (meth)acrylic acid ester monomer, the structural units derived from the aromatic vinyl monomer, the structural units derived from the vinyl cyanide monomer, and the structural units derived from other vinyl monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below is 100% by mass, a transparent thermoplastic resin composition having a content of the structural units derived from the (meth)acrylic acid ester monomer of 50 to 82% by mass can be easily produced.

[0023] Further, the other monomer (a3) copolymerizable with the aromatic vinyl monomer (a1) and the (meth)acrylate monomer (a2) is a vinyl monomer other than the aforementioned aromatic vinyl monomer (a1) and (meth)acrylate monomer (a2), and there is no particular limitation as long as the effects of the present invention are not impaired.

[0024] Specific examples of the other monomer (a3) include vinyl cyanide monomers, unsaturated fatty acids, acrylamide monomers, maleimide monomers, and the like. These may be used alone or in combination of two or more.

[0025] Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. These may be used alone or in combination of two or more. Among these, acrylonitrile is preferably used from the viewpoint of further improving the impact resistance of the molded article.

[0026] Examples of the unsaturated fatty acid include itaconic acid, maleic acid, fumaric acid, butenoic acid, acrylic acid, methacrylic acid, and the like.

[0027] Examples of the acrylamide monomer include acrylamide, methacrylamide, N-methylacrylamide, and the like.

[0028] Examples of the maleimide monomer include N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and the like.

[0029] From the viewpoint of improving the impact resistance of the molded article, the content of the other monomer (a3) in the monomer mixture (a) is preferably 2% by mass or more when the mass of the monomer mixture (a) is 100% by mass. On the other hand, from the viewpoint of improving the color tone of the molded article, it is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 5% by mass or less.

[0030] As the other monomer (a3), a vinyl cyanide-based monomer can preferably be used. The content of the vinyl cyanide-based monomer in the monomer mixture (a) is preferably 2% by mass or more when the mass of the monomer mixture (a) is 100% by mass. On the other hand, from the viewpoint of improving the color tone of the molded article, it is preferably 30% by mass or less, more preferably 20% by mass or less, and is 5% by mass or less. Within such a range, when the total of the structural units derived from (meth)acrylate-based monomers, the structural units derived from aromatic vinyl-based monomers, the structural units derived from vinyl cyanide-based monomers, and the structural units derived from other vinyl-based monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below is 100% by mass, a transparent thermoplastic resin composition in which the content of the structural units derived from vinyl cyanide-based monomers is 8 to 15% by mass can be easily produced.

[0031] A part of the graft copolymer (A) can be soluble in acetone, and the weight average molecular weight of the acetone-soluble component is not particularly limited, but is preferably 50,000 or more, and more preferably 60,000 or more. If the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is 50,000 or more, the impact resistance of the molded article can be further improved. On the other hand, the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is preferably 100,000 or less, and more preferably 90,000 or less. If the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is 100,000 or less, the fluidity of the transparent thermoplastic resin composition can be further improved. Further, if the weight average molecular weight of the acetone-soluble component is in the range of 50,000 to 100,000, a transparent thermoplastic resin composition in which the weight average molecular weight of the acetone-soluble component of the transparent thermoplastic resin composition described below is 100,000 to 120,000 can be easily produced.

[0032] In the present invention, the weight average molecular weight means the molecular weight in terms of polymethyl methacrylate. Further, in order to exclude the influence of low molecular weight substances, it is a value determined for components of 3,000 or more.

[0033] Here, the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is obtained by putting the graft copolymer (A) into acetone to dissolve the soluble component, filtering the acetone-insoluble component from the graft copolymer (A), and concentrating the filtrate with a rotary evaporator. For the collected acetone-soluble component, a solution of about 0.2 mass% in which about 0.03 g is dissolved in about 15 g of tetrahydrofuran is prepared. It can be determined by converting from the GPC chromatogram measured using this solution with polymethyl methacrylate as a standard substance. The GPC measurement can be carried out under the following conditions. Measuring device: Waters2695 Column temperature: 40 °C Detector: RI2414 (differential refractometer) Carrier eluent flow rate: 0.3 ml / min (solvent: tetrahydrofuran) Columns: TSKgel SuperHZM-M (6.0 mm I.D. × 15 cm), TSKgel SuperHZM-N (6.0 mm I.D. × 15 cm) in series (both manufactured by Tosoh Corporation).

[0034] There is no particular limitation on the grafting rate of the graft copolymer (A), but from the viewpoint of improving the impact resistance of the molded product, 10 to 100% is preferable.

[0035] Here, the grafting ratio of the graft copolymer (A) can be determined by the following method. First, 80 ml of acetone is added to about 1 g (m: sample mass) of the graft copolymer (A), and the mixture is refluxed in a water bath at 70 °C for 3 hours. After centrifuging this solution at 8000 r.p.m (10000 G) for 40 minutes, the insoluble components are filtered to obtain acetone-insoluble components. The obtained acetone-insoluble components are dried under reduced pressure at 80 °C for 5 hours, and their mass (n) is measured. The grafting ratio is calculated from the following formula. Here, X is the rubbery polymer content (%) of the graft copolymer (A).

[0036] Grafting ratio (%) = {[(n) - ((m) × X / 100)] / [(m) × X / 100]} × 100.

[0037] It is preferable that the difference in refractive index between the graft component (acetone-insoluble component) of the graft copolymer (A) and the rubbery polymer (r) is 0.03 or less, and more preferably 0.01 or less. By suppressing the difference in refractive index between the graft component (acetone-insoluble component) of the graft copolymer (A) and the rubbery polymer (r) to 0.03 or less, the transparency of the molded product can be improved.

[0038] Since the refractive index of the graft component of the graft copolymer (A) mainly depends on the composition of the vinyl monomer as the raw material, the refractive index can be adjusted to the desired range by appropriately selecting the type and composition ratio of the vinyl monomer. In particular, when the high molecular weight conversion rate is 95% or more by the emulsion polymerization method, the composition of the graft component is almost the same as the composition of the vinyl monomer mixture (a).

[0039] The refractive index of the graft component of the graft copolymer (A) can be estimated from the refractive index and content of the vinyl monomer. For example, in the case of a copolymer of styrene, methyl methacrylate, and acrylonitrile, the refractive index of the graft component of the graft copolymer (A) can be estimated by the following formula. nD(G) = (1.595 × MS / 100) + (1.490 × MM / 100) + (1.510 × MA / 100) Here, nD(G) represents the refractive index of the graft component of the graft copolymer (A), MS represents the styrene content (mass %), MM represents the methyl methacrylate content (mass %), and MA represents the acrylonitrile content (mass %). 1.595 represents the refractive index of polystyrene, 1.490 represents the refractive index of polymethyl methacrylate, and 1.510 represents the refractive index of polyacrylonitrile. The refractive indices of polystyrene, polymethyl methacrylate, and polyacrylonitrile can be measured with an Abbe refractometer.

[0040] In the present invention, the production method of the graft copolymer (A) can easily adjust the mass average particle diameter of the rubbery polymer (r) within a desired range, and can easily adjust the polymerization stability by heat removal during polymerization. Therefore, the emulsion polymerization method is more preferable.

[0041] When the graft copolymer (A) is produced by the emulsion polymerization method, the charging method of the rubbery polymer (r) and the monomer mixture (a) is not particularly limited. For example, all of these may be charged initially in one batch, or in order to adjust the distribution of the copolymer composition, a part of the monomer mixture (a) may be continuously charged, or a part or all of the monomer mixture (a) may be charged in portions. Here, continuously charging a part of the monomer mixture (a) means charging a part of the monomer mixture (a) initially and continuously charging the remainder over time. Also, charging a part or all of the monomer mixture (a) in portions means charging a part or all of the monomer mixture (a) at a time point after the initial charging.

[0042] When the graft copolymer (A) is produced by the emulsion polymerization method, various surfactants may be added as an emulsifier. As the various surfactants, anionic surfactants such as carboxylate type, sulfate ester salt type, and sulfonate type are particularly preferably used. These may be used alone or in combination of two or more. The salts mentioned here include alkali metal salts such as sodium salt, lithium salt, and potassium salt, and ammonium salts.

[0043] Examples of the carboxylate type emulsifier include caprylate, caprate, laurate, myristate, palmitate, stearate, oleate, linoleate, linolenate, rosin ate, behenate, dialkyl sulfosuccinate and the like.

[0044] Examples of the sulfate type emulsifier include castor oil sulfate, lauryl alcohol sulfate, polyoxyethylene lauryl sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate and the like.

[0045] Examples of the sulfonate type emulsifier include dodecylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl diphenyl ether disulfonate, naphthalene sulfonate condensate and the like.

[0046] When producing the graft copolymer (A) by the emulsion polymerization method, an initiator may be added as necessary. Examples of the initiator include peroxides, azo compounds, water-soluble potassium persulfate and the like. These may be used alone or in combination of two or more. Further, a redox polymerization initiator may be used as the initiator.

[0047] Examples of the peroxide include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl isopropyl carbonate, di-t-butyl peroxide, t-butyl peroxy octanoate, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy-2-ethylhexanoate and the like. Among them, cumene hydroperoxide, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane are particularly preferably used.

[0048] Examples of the azo compound include azobisisobutyronitrile, azobis(2,4-dimethyl)valeronitrile, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazohydroformamide, 1,1'-azobiscyclohexane-1-carbonitrile, azobis(4-methoxy-2,4-dimethyl)valeronitrile, dimethyl 2,2'-azobisisobutyrate, 1-t-butylazo-2-cyanobutane, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, and the like. Among them, 1,1'-azobiscyclohexane-1-carbonitrile is particularly preferably used.

[0049] The addition amount of the initiator used for producing the graft copolymer (A) is not particularly limited, but from the viewpoint of the productivity of the graft copolymer (A), 0.1 to 0.5 parts by mass is preferable with respect to 100 parts by mass in total of the rubbery polymer (r) and the monomer mixture (a).

[0050] When the graft copolymer (A) is produced by an emulsion polymerization method, a chain transfer agent may be used. By using a chain transfer agent, the graft ratio of the graft copolymer (A) can be easily adjusted to a desired range. Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, and terpenes such as terpinolene. These may be used alone or in combination of two or more. Among them, n-octyl mercaptan and t-dodecyl mercaptan are preferably used.

[0051] The addition amount of the chain transfer agent used for producing the graft copolymer (A) is not particularly limited, but from the viewpoint of easily adjusting the graft ratio of the graft copolymer (A), 0.2 to 0.7 parts by mass is preferable with respect to 100 parts by mass in total of the rubbery polymer (r) and the monomer mixture (a). The lower limit is more preferably 0.4 parts by mass or more, and the upper limit is more preferably 0.6 parts by mass or less.

[0052] When the graft copolymer (A) is produced by emulsion polymerization, there is no particular limitation on the polymerization temperature, but from the viewpoint of emulsion stability, 40 to 70 °C is preferable.

[0053] When the graft copolymer (A) is produced by an emulsion polymerization method, it is common to add a coagulant to the graft copolymer latex to recover the graft copolymer (A). As the coagulant, an acid or a water-soluble salt is preferably used.

[0054] Examples of the acid include sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, etc. Examples of the water-soluble salt include calcium chloride, magnesium chloride, barium chloride, aluminum chloride, magnesium sulfate, aluminum sulfate, ammonium aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate, etc. These may be used alone or in combination of two or more. From the viewpoint of improving the color tone of the molded article, it is preferable not to leave an emulsifier in the thermoplastic resin composition. It is preferable to use an alkali fatty acid salt as the emulsifier and coagulate with an acid. In this case, it is then preferable to neutralize with an alkali such as sodium hydroxide to remove the emulsifier.

[0055] (Vinyl copolymer (B)) The vinyl copolymer (B) constituting the transparent thermoplastic resin composition of the present invention is obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2), and a vinyl cyanide monomer (b3). The monomer mixture (b) may further contain another monomer (b4) copolymerizable with the above (b1) to (b3).

[0056] Examples of the aromatic vinyl monomer (b1) include those exemplified as the aromatic vinyl monomer (a1), and styrene is preferable.

[0057] The content of the aromatic vinyl monomer (b1) in the monomer mixture (b) is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more, based on 100% by mass of the monomer mixture (b), from the viewpoint of further improving the fluidity of the transparent thermoplastic resin composition and the transparency and rigidity of the molded article. On the other hand, the content of the aromatic vinyl monomer (b1) in the monomer mixture (b) is preferably 30% by mass or less, more preferably 27% by mass or less, and still more preferably 25% by mass or less, from the viewpoint of improving the impact resistance and transparency of the molded article. If the content of the aromatic vinyl monomer (b1) is within the above range, when the total of the structural units derived from the (meth)acrylate monomer, the structural units derived from the aromatic vinyl monomer, the structural units derived from the vinyl cyanide monomer, and the structural units derived from other vinyl monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below is 100% by mass, a transparent thermoplastic resin composition in which the content of the structural units derived from the aromatic vinyl monomer is 10 to 30% by mass can be easily produced.

[0058] Examples of the (meth)acrylate monomer (b2) include those exemplified as the (meth)acrylate monomer (a2), and methyl (meth)acrylate is preferably used.

[0059] From the viewpoint of improving the transparency of the molded article, the content of the (meth)acrylate monomer (b2) in the monomer mixture (b) is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more when the mass of the monomer mixture (b) is 100% by mass. On the other hand, from the viewpoint of further improving the transparency of the molded article, the content of the (meth)acrylate monomer (b2) in the monomer mixture (b) is preferably 82% by mass or less, more preferably 80% by mass or less, and still more preferably 75% by mass or less. When the content of the (meth)acrylate monomer (b2) is within the above range, based on 100% by mass of the total of the structural units derived from the (meth)acrylate monomer, the structural units derived from the aromatic vinyl monomer, the structural units derived from the vinyl cyanide monomer, and the structural units derived from other vinyl monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below, a transparent thermoplastic resin composition in which the content of the structural units derived from the (meth)acrylate monomer is 50 to 82% by mass can be easily produced.

[0060] Examples of the vinyl cyanide monomer (b3) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. These may be used alone or in combination of two or more. Among these, acrylonitrile is preferable from the viewpoint of further improving the impact resistance of the molded article.

[0061] From the perspective of further improving the impact resistance of the molded article, the content of the vinyl cyanide monomer (b3) in the monomer mixture (b) is preferably 4% by mass or more, more preferably 8% by mass or more, and even more preferably 9% by mass or more when the mass of the monomer mixture (b) is 100% by mass. On the other hand, from the perspective of improving the color tone of the molded article, the content of the vinyl cyanide monomer (b3) in the monomer mixture (b) is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 12% by mass or less. In particular, when the content of the vinyl cyanide monomer (b3) is in the range of 8 to 15% by mass, based on 100% by mass of the total of the structural units derived from (meth)acrylate monomers, the structural units derived from aromatic vinyl monomers, the structural units derived from vinyl cyanide monomers, and the structural units derived from other vinyl monomers contained in the acetone-soluble component of the transparent thermoplastic resin composition described below, a transparent thermoplastic resin composition in which the content of the structural units derived from vinyl cyanide monomers is 8 to 15% by mass can be easily produced.

[0062] Moreover, the other monomer (b4) copolymerizable with these is a vinyl monomer other than the aforementioned aromatic vinyl monomer (b1), (meth)acrylate monomer (b2), and vinyl cyanide monomer (b3), and there is no particular limitation as long as it is copolymerizable with these and does not impair the effects of the present invention.

[0063] Specific examples of the other monomer (b4) include unsaturated fatty acids, acrylamide monomers, maleimide monomers, etc. These may be used alone or in combination of two or more.

[0064] Examples of the unsaturated fatty acid include itaconic acid, maleic acid, fumaric acid, butenoic acid, acrylic acid, methacrylic acid, etc.

[0065] Examples of the acrylamide monomer include acrylamide, methacrylamide, N-methylacrylamide, etc.

[0066] Examples of the maleimide monomer include N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and the like.

[0067] From the viewpoints of the fluidity of the transparent thermoplastic resin composition, the impact resistance of the molded article, and the transparency, the content of the other monomer (b4) in the monomer mixture (b) is preferably 20% by mass or less, more preferably 10% by mass or less, based on 100% by mass of the monomer mixture (b).

[0068] The weight average molecular weight of the vinyl copolymer (B) is preferably 100,000 or more, more preferably 110,000 or more. By setting the weight average molecular weight of the vinyl copolymer (B) to 100,000 or more, the impact resistance of the molded article can be further improved. On the other hand, the weight average molecular weight of the vinyl copolymer (B) is preferably 130,000 or less, more preferably 120,000 or less. By setting the weight average molecular weight of the vinyl copolymer (B) to 130,000 or less, the fluidity of the transparent thermoplastic resin composition can be further improved. Further, if the weight average molecular weight of the vinyl copolymer (B) is in the range of 100,000 to 130,000, a transparent thermoplastic resin composition having a weight average molecular weight of the acetone-soluble component in the transparent thermoplastic resin composition described below in the range of 100,000 to 120,000 can be easily produced.

[0069] In order to eliminate the influence of low molecular weight substances, in the present invention, the weight average molecular weight means a value obtained by targeting components having a polymethyl methacrylate-equivalent molecular weight of 3,000 or more.

[0070] Here, the weight-average molecular weight of the vinyl copolymer (B) can be determined by conversion using polymethyl methacrylate as a standard substance from the GPC chromatogram measured using a solution of approximately 0.2 mass% prepared by dissolving approximately 0.03 g of the vinyl copolymer (B) in approximately 15 g of tetrahydrofuran. The GPC measurement can be carried out under the following conditions. Measuring device: Waters2695 Column temperature: 40 °C Detector: RI2414 (differential refractometer) Carrier eluent flow rate: 0.3 ml / min (solvent: tetrahydrofuran) Column: TSKgel SuperHZM-M (6.0 mm I.D. × 15 cm), TSKgel SuperHZM-N (6.0 mm I.D. × 15 cm) in series (both manufactured by Tosoh Corporation).

[0071] The vinyl copolymer (B) preferably has a difference in refractive index of 0.03 or less, more preferably 0.01 or less, between the refractive index of the vinyl copolymer (B) and the rubbery polymer (r) contained in the above graft copolymer (A). By suppressing the difference in refractive index between the vinyl copolymer (B) and the rubbery polymer (r) to 0.03 or less, the transparency of the molded product can be improved.

[0072] Since the refractive index of the vinyl copolymer (B) mainly depends on the composition of the vinyl monomer as a raw material, the refractive index can be adjusted to a desired range by appropriately selecting the type and composition ratio of the vinyl monomer. The refractive index of the vinyl copolymer (B) can be estimated from the refractive index and content of the vinyl monomer. For example, in the case of a copolymer of styrene, methyl methacrylate, and acrylonitrile, the refractive index of the vinyl copolymer (B) can be estimated by the following formula.

[0073] nD(B)=(1.595×MS / 100)+(1.490×MM / 100)+(1.510×MA / 100) Here, nD(B) represents the refractive index of the vinyl copolymer (B), MS represents the styrene content (mass %), MM represents the methyl methacrylate content (mass %), and MA represents the acrylonitrile content (mass %). 1.595 represents the refractive index of polystyrene, 1.490 represents the refractive index of polymethyl methacrylate, and 1.510 represents the refractive index of polyacrylonitrile. The refractive indices of polystyrene, polymethyl methacrylate, and polyacrylonitrile can all be measured with an Abbe refractometer.

[0074] Also, the refractive index of the vinyl copolymer (B) can be measured with an Abbe refractometer.

[0075] In the present invention, the method for producing the vinyl copolymer (B) is not particularly limited, but from the viewpoints of the fluidity of the resulting transparent thermoplastic resin composition, the transparency and color tone of the molded article, the continuous bulk polymerization method or the continuous solution polymerization method is preferably used.

[0076] As a method for producing the vinyl copolymer (B) by the continuous bulk polymerization method or the continuous solution polymerization method, any conventionally known method can be adopted. For example, a method of polymerizing the monomer mixture (b) in a polymerization tank and then removing the monomer (removing the solvent and volatiles) can be mentioned.

[0077] As the polymerization tank, for example, a mixing type polymerization tank having stirring blades such as paddle blades, turbine blades, propeller blades, burmergin blades, multi-stage blades, anchor blades, max blend blades, double helical blades, or various tower-type reactors can be used. Also, a multi-tube reactor, a kneader-type reactor, a twin-screw extruder, etc. can be used as the polymerization reactor (for example, refer to "Assessment of Impact-Resistant Polystyrene" in Assessment of Polymer Manufacturing Processes 10, The Polymer Society, published on January 26, 1989, etc.).

[0078] Two or more of these polymerization tanks or polymerization reactors may be used, or two or more types of polymerization tanks or polymerization reactors may be combined as necessary. From the viewpoint of reducing the dispersity of the vinyl copolymer (B), the number of polymerization tanks or polymerization reactors is preferably two or less, and a one-tank complete mixing type polymerization tank is more preferable.

[0079] The reaction mixture obtained by polymerization in these polymerization tanks or polymerization reactors is usually then subjected to a de-monomer step, and monomers, solvents and other volatile components are removed. Examples of the method for de-monomer include, for example, a method of removing volatile components from a vent hole under normal pressure or reduced pressure by heating with a single-screw or twin-screw extruder having a vent, a method of removing volatile components with an evaporator having a plate fin type heater such as a centrifugal type built in a drum, a method of removing volatile components with a thin film evaporator such as a centrifugal type, a method of preheating using a multi-tube heat exchanger, foaming and flashing into a vacuum tank to remove volatile components, and the like. Among these, a method of removing volatile components with a single-screw or twin-screw extruder having a vent is particularly preferably used.

[0080] When producing the vinyl copolymer (B), an initiator or a chain transfer agent may be used as necessary. Examples of the initiator and the chain transfer agent include the initiators and chain transfer agents exemplified in the method for producing the graft copolymer (A). The initiator is also used in a redox system.

[0081] There is no particular limitation on the addition amount of the initiator used for producing the vinyl copolymer (B), but from the viewpoint of easily adjusting the weight average molecular weight of the vinyl copolymer (B) to the above-mentioned range, 0.01 to 0.10 parts by mass is preferable with respect to 100 parts by mass in total of the vinyl monomer mixture (b).

[0082] The amount of the chain transfer agent used for producing the vinyl copolymer (B) is not particularly limited, but from the viewpoint of easily adjusting the weight average molecular weight of the vinyl copolymer (B) to the above-mentioned range, 0.10 to 0.40 parts by mass is preferable with respect to 100 parts by mass in total of the vinyl monomer mixture (b). The lower limit is more preferably 0.20 parts by mass or more, and the upper limit is more preferably 0.30 parts by mass or less.

[0083] When the vinyl copolymer (B) is produced by a continuous bulk polymerization method or a continuous solution polymerization method, the polymerization temperature is not particularly limited, but from the viewpoint of easily adjusting the weight average molecular weight of the vinyl copolymer (B) to the above-mentioned range, 120°C to 140°C is preferable.

[0084] When the vinyl copolymer (B) is produced by a continuous solution polymerization method, the amount of the solvent is preferably 30% by mass or less, more preferably 20% by mass or less in the polymerization solution from the viewpoint of productivity. As the solvent, ethylbenzene or methyl ethyl ketone is preferable, and ethylbenzene is particularly preferably used from the viewpoint of polymerization stability.

[0085] (Transparent thermoplastic resin composition) In the transparent thermoplastic resin composition of the present invention, based on a total of 100 parts by mass of the graft copolymer (A) and the vinyl copolymer (B), it is preferable that the graft copolymer (A) is 10 to 60 parts by mass and the vinyl copolymer (B) is 40 to 90 parts by mass. When the content of the graft copolymer (A) is less than 10 parts by mass and the content of the vinyl copolymer (B) exceeds 90 parts by mass, the impact resistance of the molded product may decrease. It is more preferable to contain 20 parts by mass or more of the graft copolymer (A) and 80 parts by mass or less of the vinyl copolymer (B) based on a total of 100 parts by mass of the graft copolymer (A) and the vinyl copolymer (B). On the other hand, when the content of the graft copolymer (A) exceeds 60 parts by mass and the content of the vinyl copolymer (B) is less than 40 parts by mass, the melt viscosity of the transparent thermoplastic resin composition increases, the fluidity decreases, and the transparency of the molded product may also decrease. It is more preferable to contain 50 parts by mass or less of the graft copolymer (A) and 50 parts by mass or more of the vinyl copolymer (B) based on a total of 100 parts by mass of the graft copolymer (A) and the vinyl copolymer (B).

[0086] The weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition of the present invention is preferably 100,000 to 120,000. By setting the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition to 100,000 or more, the impact resistance of the molded product can be further improved. On the other hand, by setting the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition to 120,000 or less, the fluidity of the transparent thermoplastic resin composition can be further improved.

[0087] Here, the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition can be measured by the same procedure as described in the section of the graft copolymer (A) after putting the transparent thermoplastic resin composition into acetone to dissolve the soluble component.

[0088] In the acetone-soluble component contained in the transparent thermoplastic resin composition of the present invention, the content of the structural unit derived from the (meth)acrylate monomer is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 60% by mass or more, from the viewpoint of improving the transparency of the molded article, when the total of the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers is 100% by mass. On the other hand, from the viewpoint of further improving the transparency of the molded article, it is preferably 82% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less.

[0089] In the acetone-soluble component contained in the transparent thermoplastic resin composition of the present invention, the content of the structural unit derived from the aromatic vinyl monomer is preferably 10% by mass or more, more preferably 15% by mass, still more preferably 20% by mass or more, from the viewpoint of further improving the fluidity of the transparent thermoplastic resin composition and the transparency and rigidity of the molded article, when the total of the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers is 100% by mass. On the other hand, from the viewpoint of further improving the impact resistance and transparency of the molded article, it is preferably 30% by mass or less, more preferably 27% by mass or less, still more preferably 25% by mass or less.

[0090] In the acetone-soluble component contained in the transparent thermoplastic resin composition of the present invention, the content of the structural unit derived from the vinyl cyanide monomer is preferably 8% by mass or more, more preferably 9% by mass or more, from the viewpoint of further improving the impact resistance of the molded article, when the total of the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers is 100% by mass. On the other hand, from the viewpoint of further improving the color tone of the molded article, it is preferably 15% by mass or less, more preferably 13% by mass or less, still more preferably 11% by mass or less.

[0091] Here, the "structural unit" means a repeating unit corresponding to or corresponding to each monomer when describing the structural formula of a polymer, where the polymer is formed by the polymerization of a large number of monomers. For example, in polystyrene, the structural unit derived from styrene is [-CH2―CH(C6H5)-].

[0092] From the viewpoint of the balance between the fluidity of the transparent thermoplastic resin composition and the impact resistance of the molded article, the content of the rubbery polymer (r) contained in the transparent thermoplastic resin composition is based on the total of the rubbery polymer (r), the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers being 100% by mass. It is preferably 12 to 22% by mass. More preferably, it is 15% by mass or more and 20% by mass or less.

[0093] The content of the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers in the acetone-soluble component contained in the transparent thermoplastic resin composition, with respect to 100% by mass of the total, can be determined by the following method.

[0094] The transparent thermoplastic resin composition is put into acetone to dissolve the soluble component, and the filtrate obtained by filtering the acetone-insoluble component from the transparent thermoplastic resin composition is concentrated and dried with a rotary evaporator. For the acetone-soluble component collected in this way, for a film with a thickness of 30 ± 5 μm produced by a heating press set at 230°C, FT-IR analysis is performed, and the content of the structural unit derived from each monomer can be quantified from the calibration curve prepared in advance from the intensity ratio of the following peaks appearing in the FT-IR spectrum chart. The relationship between the structural unit derived from each monomer and the peak is described below.

[0095] (Meth)acrylate monomer-derived structural unit: a peak at 3460 cm which is the overtone peak of the peak at 1730 cm attributed to the stretching vibration of the carbonyl group C=O of the ester -1 -1 of the peak.

[0096] Aromatic vinyl monomer-derived structural unit: a peak at 1605 cm attributed to the vibration of the benzene nucleus -1 of the peak.

[0097] Vinyl cyanide monomer-derived structural unit: a peak at 2240 cm attributed to C≡N stretching -1 of the peak.

[0098] Also, for the rubbery polymer (r), the content of the rubbery polymer (r) with respect to the total 100% by mass of the structural units derived from (meth)acrylate monomers, aromatic vinyl monomers, vinyl cyanide monomers, and other vinyl monomers can be quantified from a calibration curve prepared in advance from the intensity ratios of the peaks of the structural units derived from each monomer and the rubbery polymer (r) that appear in the FT-IR spectrum chart for a film with a thickness of 30 ± 5 μm prepared by a hot press set at 230 °C for the transparent thermoplastic resin composition. The relationship between the rubbery polymer (r) and the peak is described below.

[0099] Rubbery polymer (r): a peak at 960 cm attributed to C=C -1 of the peak.

[0100] ​In the transparent thermoplastic resin composition of the present invention, when the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition is Mw1, and the content (mass %) of the structural unit derived from the vinyl cyanide-based monomer contained in the acetone-soluble component is W1 with the mass of the acetone-soluble component being 100 mass %, it is preferable that the value obtained by dividing Mw1 by W1 is 11,000 or more. For example, when the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition is 500,000 and the content of the structural unit derived from the vinyl cyanide-based monomer contained in the acetone-soluble component is 5% with the mass of the acetone-soluble component being 100 mass %, the value obtained by dividing Mw1 by W1 is 100,000. When the value obtained by dividing Mw1 by W1 is less than 11,000, the effect of improving the impact resistance of the structural unit derived from the vinyl cyanide-based monomer constituting the vinyl copolymer (B) becomes insufficient, and the impact resistance of the molded product may decrease, which is not preferable.

[0101] The transparent thermoplastic resin composition of the present invention further contains an ester compound (C) and an ester compound (D) in addition to the graft copolymer (A) and the vinyl copolymer (B).

[0102] The ester compound (C) is a hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid, and 85 mass % or more of the acids constituting the triglyceride is a hydrogenated product of ricinoleic acid, that is, 12-hydroxystearic acid.

[0103] Therefore, the main component of the ester compound (C) is an ester obtained from 12-hydroxystearic acid and glycerin.

[0104] As the ester compound (C), those synthesized by esterifying the above acid and glycerin may be used. However, as it is known as natural castor hardened oil, in the present invention, it is economically advantageous to use castor hardened oil to obtain the transparent thermoplastic resin composition of the present invention.

[0105] When using castor oil as the ester compound (C), the iodine value of castor oil is not particularly limited, but from the viewpoint of improving the color tone of the molded product, it is preferably 5 or less, more preferably 3 or less. If the iodine value is 5 or less, discoloration due to thermal deterioration during processing can be suppressed. The iodine value is a value measured in accordance with JIS K0070:1992.

[0106] The content of the ester compound (C) is preferably 0.4 to 2.0 parts by mass, more preferably 0.4 to 0.8 parts by mass, based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B). If the content of the ester compound (C) is 0.4 parts by mass or more based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the impact resistance of the molded product can be improved and the fluidity of the transparent thermoplastic resin composition can be improved. On the other hand, if the content of the ester compound (C) is 2.0 parts by mass or less based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the impact resistance of the molded product can be improved without impairing the transparency of the molded product, and furthermore, the fluidity of the transparent thermoplastic resin composition can be improved. In particular, if the content of the ester compound (C) is in the range of 0.4 to 0.8 parts by mass based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the impact resistance of the molded product and the fluidity of the transparent thermoplastic resin composition can be improved, the mold release property during molding can be improved, and furthermore, the amount of gas generated during molding can be reduced and mold fouling can be more effectively suppressed.

[0107] The ester compound (D) is an ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid.

[0108] A polyhydric alcohol means a compound having two or more hydroxyl groups in one molecule. There is no particular limitation as long as it is a compound having two or more hydroxyl groups, but a C2-C30 di- to hexavalent polyhydric alcohol is preferably used.

[0109] Among the above di- to hexavalent polyhydric alcohols, examples of the divalent alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1,30-triacontanediol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spiroglycol, 1,4-phenyleneglycol, bisphenol A, hydrogenated bisphenol A, etc. Examples of the trivalent alcohol include 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methyl-1,2,4-butanetriol, glycerin, 2-methylpropanetriol, trimethylolethane, triethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Examples of the tetravalent alcohol include 1,2,3,6-hexanetetrol, pentaerythritol, etc. Examples of the pentavalent alcohol include glucose, etc. Examples of the hexavalent alcohol include dipentaerythritol, etc.

[0110] The ester compound (D) may be synthesized by esterifying the above acid and polyhydric alcohol, but it is economically advantageous to obtain it from natural fats and oils or processed natural fats and oils. In particular, it is convenient to use castor oil, which is a type of vegetable oil obtained by pressing the seeds of castor (Ricinus communis L.), or a compound modified using castor oil or its derivative (castor oil-based polyester polyol) as a starting material. The composition of the fatty acids in castor oil, which constitutes castor oil, is known to be 87-91% ricinoleic acid, 4-5% linoleic acid, 2.5-4% oleic acid, 0.5-1.5% palmitic acid, 0.5-1.5% stearic acid, 0.5-1.5% linolenic acid, and 0.5-1.5% dihydroxystearic acid.

[0111] When using a castor oil-based polyester polyol as the ester compound (D), examples include polyester polyols produced using castor oil or castor oil fatty acids. Furthermore, transesterification products of castor oil and other natural fats and oils, reaction products of castor oil and polyhydric alcohols, esterification reaction products of castor oil fatty acids and polyhydric alcohols, etc. may be mentioned. These may be used alone or in combination of two or more.

[0112] It is preferable to use an ester compound (D) having a hydroxyl value of 170 mgKOH / g or more, and more preferably 200 mgKOH / g or more. If an ester compound having a hydroxyl value of 170 mgKOH / g or more is used, the fluidity of the transparent thermoplastic resin composition can be improved while further improving the transparency of the molded article. The upper limit is preferably 350 mgKOH / g or less.

[0113] Also, the acid value of the ester compound (D) is preferably 15 mgKOH / g or less. More preferably, it is 10 mgKOH / g or less, still more preferably 8 mgKOH / g or less, and particularly preferably 2 mgKOH / g or less. If the acid value is 15 mgKOH / g or less, the ester compound (D) has high heat resistance, can reduce the amount of gas generated during molding of unreacted residual fatty acids, which are low-molecular components, can suppress mold fouling, and in addition, the color tone of the molded product is improved.

[0114] The acid value and the hydroxyl value are values measured in accordance with JIS K0070:1992.

[0115] Furthermore, the viscosity of the ester compound (D) at 25°C is preferably 200 to 1500 mPa·s, more preferably 200 to 750 mPa·s, and still more preferably 200 to 500 mPa·s. If the viscosity is 200 mPa·s or more, the amount of gas generated during molding of the ester compound (D) during molding can be reduced, and mold fouling can be suppressed. On the other hand, if the viscosity is 1500 mPa·s or less, the fluidity of the transparent thermoplastic resin composition can be further improved. The viscosity is a value measured in accordance with JIS Z8803:2011.

[0116] When using castor oil or a castor oil-based polyester polyol as the ester compound (D) used in the present invention, the castor oil or the castor oil-based polyester polyol may be produced according to a known production method, or a commercially available product may be used. Examples of commercially available products of castor oil or castor oil-based polyester polyols include the URIC H series (H-30, H-31, H-52, H-57, H-62, H-73X, H-81, H-854, H-870, H-1823, H-1824, HF-1300), URIC Y series (Y-403, Y-406), URIC AC series (AC-005, AC-006, AC-009), URIC PH series (PH-5001), URIC F series (F-40, F-60, F-97), etc. manufactured by Ito Seiyu Co., Ltd. Among them, from the viewpoints of the transparency of the molded product, impact resistance, and fluidity of the transparent thermoplastic resin composition, H-30, H-62, and H-73X are preferably used.

[0117] In the present invention, the content of the ester compound (D) in the transparent thermoplastic resin composition is preferably 0.4 to 3.0 parts by mass, more preferably 0.6 to 2.4 parts by mass, based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B). The upper limit is more preferably 1.5 parts by mass or less. If the content of the ester compound (D) is 0.4 parts by mass or more based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the fluidity of the transparent thermoplastic resin composition can be improved, and the mold release property of the molded product can be improved. On the other hand, if the content of the ester compound (D) is 3.0 parts by mass or less based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the fluidity of the transparent thermoplastic resin composition can be further improved without impairing the transparency and impact resistance of the molded product. In particular, if the content of the ester compound (D) is in the range of 0.6 to 2.4 parts by mass based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), the impact resistance of the molded product, the fluidity of the transparent thermoplastic resin composition, the mold release property during molding can be improved, the amount of gas generated during molding can be reduced, and mold fouling can be suppressed.

[0118] The ester compound (C) is considered to be particularly present unevenly around the rubbery polymer (r) in the transparent thermoplastic resin composition because it greatly contributes to improving the impact resistance of the molded product. As a result, the elastic modulus around the rubbery polymer (r) can be lowered, the sharp elastic modulus difference between the rubber phase and the matrix phase can be alleviated, and the stress concentration at the interface can be alleviated. Further, by being unevenly distributed around the rubbery polymer (r), the slipperiness of the rubbery polymer (r) against impact can be improved, and the impact absorption ability of the rubbery polymer (r) can be enhanced. On the other hand, if too much is added, the effect of improving the impact resistance of the molded product reaches a peak, the mold release property deteriorates, the amount of gas generated during molding increases, and it may cause mold fouling, which is not preferable. The ester compound (D) is considered to have good dispersibility in the matrix phase of the transparent thermoplastic resin composition because it particularly greatly contributes to improving the fluidity of the transparent thermoplastic resin composition. Also, transparency can be maintained. On the other hand, if too much is added, the impact resistance of the molded product decreases, the amount of gas generated during molding increases, and it may cause mold fouling, which is not preferable.

[0119] For the above reasons, in the transparent thermoplastic resin composition of the present invention, from the viewpoints of improving the impact resistance of the molded product, improving the fluidity of the transparent thermoplastic resin composition, having good mold release property during molding, and reducing the amount of gas generated during molding, it is preferable that the ester compound (C) and the ester compound (D) are contained in a mass ratio of 25:75 to 40:60. If the ester compound (D) exceeds 75% by mass and the ester compound (C) is less than 25% by mass, it may not be possible to sufficiently obtain the impact resistance of the molded product, which is not preferable. On the other hand, if the ester compound (D) is less than 60% by mass and the ester compound (C) exceeds 40% by mass, the fluidity of the transparent thermoplastic resin composition cannot be sufficiently obtained, and the mold release property may deteriorate, which is not preferable.

[0120] In addition, the transparent thermoplastic resin composition of the present invention may contain a carboxylic acid ester of a polyhydric alcohol that does not correspond to either the ester compound (C) or the ester compound (D) as long as it does not inhibit the object of the present invention.

[0121] The transparent thermoplastic resin composition of the present invention may further contain polydimethylsiloxane gum (E). The polydimethylsiloxane gum (E) referred to herein means a gum-like polydimethylsiloxane having a weight average molecular weight of 300,000 or more. If the weight average molecular weight is 300,000 or more, the polydimethylsiloxane becomes gum-like rather than liquid. The weight average molecular weight of the polydimethylsiloxane gum (E) is measured by the same method as described for the acetone-soluble component of the graft copolymer (A) or the vinyl copolymer (B), but is a value converted using polystyrene as a standard substance.

[0122] The content of the polydimethylsiloxane gum (E) is not particularly limited, but from the viewpoint of further improving the impact resistance without impairing the transparency and mold release properties, based on 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), it is preferably 15 to 100 ppm (that is, 15×10 -6 ~100×10 -6 parts by mass), and more preferably 30 to 80 ppm.

[0123] The transparent thermoplastic resin composition of the present invention may further contain various antioxidants.

[0124] Examples of phenolic antioxidants include reaction products of p-cresol, dicyclopentadiene, and isobutylene; 2,2'-methylenebis(4-methyl-6-t-butylphenol); 2,6-di-t-butyl-4-methylphenol; triethylene glycol-bis-[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate]; pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene; 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate; 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)]-4,6-di-t-pentylphenyl acrylate (548.9, 1 piece); 3,9-bis[2-{3-(t-butyl-4-hydroxy-5-methylphenyl)propoxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxa[5,5]undecane; 1,3,5-tris(3',5')-di-t-butyl-4'-hydroxybenzyl-s-triazine 2,4,6(1H,2H,3H)-trione; 1,1,4-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane; 4,4'-butylidenebis(3-methyl-6-t-butylphenol) and other 2,4,5- or 2,4,6-trisphenols; reaction products of p-cresol, dicyclopentadiene, and isobutylene, and the like.

[0125] Examples of phosphorus antioxidants include pentaerythritol type diphosphite compounds such as tris(2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)-pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)-pentaerythritol diphosphite, 2,2-methylenebis(4,6-di-t-butylphenyl) octyl phosphite, dinonylphenyl pentaerythritol diphosphite, and the like.

[0126] Examples of the sulfur-based antioxidants include distearyl 3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, dilauryl thiodipropionate, lauryl stearyl thiodipropionate, pentaerythritol tetrakis(3-laurylthiopropionate), and the like.

[0127] In the transparent thermoplastic resin composition of the present invention, if necessary, within a range not impairing the object of the present invention, inorganic fillers such as glass fiber, glass powder, glass beads, glass flakes, alumina, alumina fiber, carbon fiber, graphite fiber, stainless steel fiber, whisker, potassium titanate fiber, wollastonite, asbestos, hard clay, fired clay, talc, kaolin, mica, calcium carbonate, magnesium carbonate, aluminum oxide, and minerals; hindered phenol-based, acrylate-based, etc. heat stabilizers; benzotriazole-based, benzophenone-based, or salicylate-based ultraviolet absorbers; hindered amine-based light stabilizers; lubricants and plasticizers such as higher fatty acids, acid esters, acid amides, or higher alcohols; mold release agents such as montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide, and ethylene wax; various flame retardants; flame retardant aids; coloring inhibitors such as phosphites and hypophosphites; neutralizing agents such as phosphoric acid, sodium monophosphate, maleic anhydride, and succinic anhydride; nucleating agents; antistatic agents such as amine-based, sulfonic acid-based, and polyether-based; coloring agents such as carbon black, pigments, and dyes can be blended.

[0128] In the present invention, "transparent" means that the total light transmittance of a square plate molded article (50 mm in length, 40 mm in width, and 3 mm in thickness) measured using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd. is 80% or more.

[0129] As one aspect of the transparent thermoplastic resin composition of the present invention, in a square plate molded article (50 mm in length, 40 mm in width, 3 mm in thickness) serving as an index of transparency, the total light transmittance is 87% or more, the haze is 3 or less, and the Charpy impact strength serving as an index of impact resistance is 14 kJ / m 2 or more, and an MFR (220 °C, 98 N) serving as an index of fluidity is 20 g / 10 min or more, and a transparent thermoplastic resin composition with good mass productivity can be obtained. Further, the content of the ester compound (C) is 0.4 to 0.8 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), and the content of the ester compound (D) is 0.8 to 2.4 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl copolymer (B), and the mass ratio of the ester compound (C) to the ester compound (D) is 25:75 to 40:60, and by using an ester (D) having a hydroxyl value of 170 to 350 mgKOH / g, the total light transmittance is 88% or more, the haze is 2 or less, and the Charpy impact strength is 15 kJ / m 2 or more, and an MFR (220 °C, 98 N) is 22 g / 10 min or more, and it becomes easy to obtain a transparent thermoplastic resin composition in which the number of whitened portions when filled at the lower limit pressure +60 MPa during molding is 8 or less and the mass productivity is good.

[0130] (Method for producing a transparent thermoplastic resin composition) Next, the method for producing the transparent thermoplastic resin composition of the present invention will be described. The transparent thermoplastic resin composition of the present invention can be obtained, for example, by blending the above-mentioned graft copolymer (A), vinyl copolymer (B), ester compound (C), ester compound (D), and other components such as polydimethylsiloxane gum (E) as necessary, and melt-kneading them. A method in which the vinyl copolymer (B) is continuously bulk polymerized, and further the graft copolymer (A), ester compound (C), ester compound (D), and other components such as polydimethylsiloxane gum (E) as necessary are continuously melt-kneaded is more preferable. By continuously performing the production of the final transparent thermoplastic resin composition from the production of the vinyl copolymer (B), the thermal history is reduced, and the color tone of the transparent thermoplastic resin composition becomes good.

[0131] Figure 1 shows a schematic view of an embodiment of an apparatus for producing a transparent thermoplastic resin composition preferably used in the present invention. The apparatus for producing the transparent thermoplastic resin composition shown in Figure 1 includes a completely mixed polymerization tank 1 for producing a vinyl copolymer (B), a single-screw extruder type preheater 2 for heating the obtained vinyl copolymer (B) to a predetermined temperature, and a twin-screw extruder type monomer remover 3, each of which is connected. Further, a twin-screw extruder type feeder 5 for supplying a graft copolymer (A), an ester compound (C), an ester compound (D), and, if necessary, polydimethylsiloxane gum (E) is connected so as to side-feed the twin-screw extruder type monomer remover 3. The completely mixed polymerization tank 1 has a stirrer (helical ribbon blade) 7, and the twin-screw extruder type monomer remover 3 has a vent port 8 for removing volatile components such as unreacted monomers.

[0132] The reaction product (vinyl copolymer (B)) continuously supplied from the completely mixed polymerization tank 1 is heated to a predetermined temperature by the single-screw extruder type preheater 2 and then supplied to the twin-screw extruder type monomer remover 3. In the twin-screw extruder type monomer remover 3, generally at a temperature of about 150 to 280°C, under normal pressure or reduced pressure, volatile components such as unreacted monomers are removed from the system through the vent port 8. The removal of this volatile component is generally carried out until the volatile component reaches a predetermined amount, for example, 10% by mass or less, more preferably 5% by mass or less. Further, the removed volatile component is preferably supplied again to the completely mixed polymerization tank 1.

[0133] Through an opening provided at a position near the downstream side in the middle of the twin-screw extruder type monomer-removing machine 3, the graft copolymer (A), the ester compound (C), and, if necessary, the polydimethylsiloxane gum (E) are supplied from the twin-screw extruder type feeder 5. Further, from the liquid additive addition nozzle 11, which is located two-thirds of the total length before the downstream tip of the twin-screw extruder feeder 5 (the position where the twin-screw extruder type feeder 5 of the twin-screw extruder type monomer-removing machine 3 is connected), the ester compound (D) is supplied to the twin-screw extruder feeder 5 using a liquid addition pump. The twin-screw extruder type feeder 5 preferably has a heating device, and by supplying the graft copolymer (A) to the twin-screw extruder type monomer-removing machine 3 in a semi-molten or molten state, the mixing state can be improved. The heating temperature of the graft copolymer (A) is generally 100 to 220°C. Examples of the twin-screw extruder type feeder 5 include a twin-screw extruder type feeder composed of a screw, a cylinder, and a screw drive unit, where the cylinder has a heating and cooling function.

[0134] At the position where the twin-screw extruder type feeder 5 of the twin-screw extruder type monomer-removing machine 3 is connected, in order to suppress the thermal degradation of the rubber component due to the operation of removing the subsequent unreacted monomer, it is preferable that the content of the unreacted monomer is reduced to 10% by mass or less, more preferably 5% by mass or less.

[0135] In the melt-kneading zone 4, which is the downstream area after the position where the twin-screw extruder type feeder 5 of the twin-screw extruder type monomer-removing machine 3 is connected, the vinyl copolymer (B), the graft copolymer (A), the ester compound (C), the ester compound (D), and, if necessary, the polydimethylsiloxane gum (E) are melt-kneaded, and the transparent thermoplastic resin composition is discharged out of the system from the discharge port 6. It is preferable to provide a water injection port 9 in the melt-kneading zone 4 and add a predetermined amount of water. The injected water and volatile components such as unreacted monomers are removed out of the system from the final vent port 10 provided further downstream.

[0136] In addition, since the amount of polydimethylsiloxane gum (E) added is small, a resin diluent of polydimethylsiloxane gum is preferably prepared in advance by the method described in International Publication No. 2021 / 014736, and polydimethylsiloxane gum (E) is added as a resin diluent of polydimethylsiloxane gum having a polydimethylsiloxane gum (E) content of about 10% by mass.

[0137] The transparent thermoplastic resin composition of the present invention can be molded by any molding method. Examples of the molding method include injection molding, extrusion molding, inflation molding, blow molding, vacuum molding, compression molding, gas-assisted molding, etc., and injection molding is preferably used. The cylinder temperature during injection molding is preferably 210 to 320°C, and the mold temperature is preferably 30 to 80°C.

[0138] The transparent thermoplastic resin composition of the present invention can be widely used as a molded product of any shape. Examples of the molded product include films, sheets, fibers, fabrics, non-woven fabrics, injection molded products, extrusion molded products, vacuum and pressure molding products, blow molded products, composites with other materials, etc.

[0139] Since the transparent thermoplastic resin composition of the present invention can have excellent impact resistance and fluidity while maintaining particularly high transparency and good color tone, it is useful as applications such as household appliances, communication-related equipment, general goods, and medical-related equipment.

Examples

[0140] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention should not be construed as being limited to these examples. First, the evaluation method will be described.

[0141] <Evaluation Method of Transparent Thermoplastic Resin Composition> (1) Transparency (HAZE, haze) After drying the pellets of the resin composition of the sample in a hot air dryer at 80°C for 3 hours, they were filled into a SE-50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd. with the cylinder temperature set at 230°C, and immediately a square plate molded product with a thickness of 3 mm was molded. Using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd., for each of the five obtained square plate molded products, HAZE (%) was measured by a method conforming to ISO 14782, and the number average value thereof was calculated.

[0142] (2) Transparency (total light transmittance) After drying the pellets of the resin composition of the sample in a hot air dryer at 80°C for 3 hours, they were filled into a SE-50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd. with the cylinder temperature set at 230°C, and immediately a square plate molded product with a thickness of 3 mm was molded. Using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd., for each of the five obtained square plate molded products, the total light transmittance (%) was measured by a method conforming to ISO 13468, and the number average value thereof was calculated.

[0143] (3) Impact resistance (Charpy impact strength) After drying the pellets of the resin composition of the sample in a hot air dryer at 80°C for 3 hours, they were filled into a SE-50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd. with the cylinder temperature set at 230°C, and immediately dumbbell test pieces with a thickness of 4 mm were molded. For each of the five obtained dumbbell test pieces, the Charpy impact strength was measured by a method conforming to ISO179, and the number average value thereof was calculated.

[0144] (4) Fluidity (melt flow rate (MFR)) After drying the pellets of the resin composition of the sample in a hot air dryer at 80°C for 3 hours, MFR was measured by a method conforming to ISO1133 under the conditions of a measurement temperature of 220°C and a load of 98 N.

[0145] (5) Release property After drying the pellets of the resin composition of the sample in a hot air dryer at 80°C for 3 hours, they were filled into a PS60 molding machine manufactured by Nissei Plastic Industrial Co., Ltd. with the cylinder temperature set at 230°C, the mold temperature at 60°C, and the cooling time at 20 seconds. The pressure was switched to pressure control at the gate position, and the lower limit pressure at which the resin could be filled into the shape of the molded product shown in Fig. 2 was determined. Next, for five molded products each molded under the condition of the lower limit pressure + 60 MPa, the number of whitened portions was counted visually, and the number average value was calculated.

[0146] (6) Mass productivity After manufacturing the pellets of the resin composition for 2 hours according to the procedures described in each of the examples and comparative examples, the screen mesh (#150 mesh) was checked, and the presence or absence of gelled products (clogging materials) was visually confirmed.

[0147] Good: No gelled products (clogging materials) Poor: There are gelled products (clogging materials).

[0148] <Production of transparent thermoplastic resin composition> (Production Example 1) Graft copolymer (A) Graft copolymer (A-1): In a reaction vessel with an internal volume of 25 m equipped with stirring blades 3 , 50 parts by mass (in terms of solid content) of polybutadiene latex (rubber mass average particle diameter 0.30 μm, refractive index 1.516), 130 parts by mass of pure water, 0.4 part by mass of sodium laurate, 0.2 part by mass of glucose, 0.2 part by mass of sodium pyrophosphate, and 0.01 part by mass of ferrous sulfate were charged. After nitrogen substitution, the temperature was adjusted to 60°C, and while stirring, a monomer mixture of 3.4 parts by mass of styrene, 1.4 parts by mass of acrylonitrile, 10.2 parts by mass of methyl methacrylate, and 0.12 part by mass of t-dodecyl mercaptan was initially added over 45 minutes.

[0149] Next, an initiator mixture consisting of 0.3 parts by mass of cumene hydroperoxide, 1.6 parts by mass of sodium laurate as an emulsifier, and 25 parts by mass of pure water was continuously added dropwise over 5 hours. Simultaneously and in parallel, a monomer mixture consisting of 2.8 parts by mass of styrene, 0.6 parts by mass of acrylonitrile, 8.3 parts by mass of methyl methacrylate, and 0.13 parts by mass of t-dodecyl mercaptan was continuously added dropwise over 1 hour, and then, subsequently, a monomer mixture consisting of 5.8 parts by mass of styrene, 17.5 parts by mass of methyl methacrylate, and 0.27 parts by mass of t-dodecyl mercaptan was continuously added dropwise over 2 hours. After the addition of the monomer mixture, only the initiator mixture was continuously added for 2 hours, and nothing was added for an additional 1 hour to maintain the polymerization and complete the polymerization. After the completion of the polymerization, an emulsified dispersion of the reaction product of p-cresol·dicyclopentadiene·isobutylene was added in an amount of 0.4 parts by mass based on the solid content of the reaction product of p-cresol·dicyclopentadiene·isobutylene with respect to 100 parts by mass of the graft copolymer (A-1). The obtained graft copolymer latex was coagulated with 1.5% by mass sulfuric acid, neutralized with sodium hydroxide, washed, centrifuged, and dried to obtain a powdery graft copolymer (A-1) mixed with the reaction product of p-cresol·dicyclopentadiene·isobutylene (ratio of structural units derived from monomers: 24% by mass of structural units derived from styrene, 4% by mass of structural units derived from acrylonitrile, 72% by mass of structural units derived from methyl methacrylate). The refractive index of the acetone-insoluble component of the obtained graft copolymer (A-1) was 1.516, and the difference in refractive index from the rubbery polymer (r) was 0.000. The grafting ratio was 47%. Also, the weight-average molecular weight of the acetone-soluble component was 72,000. (Production Example 2) Vinyl-based copolymer (B) Vinyl copolymer (B-1’): In Example 1, except that the supply of various materials from the twin-screw extruder type feeder was not performed and the styrene / acrylonitrile / methyl methacrylate copolymer was produced by supply from the completely mixed polymerization tank, the styrene / acrylonitrile / methyl methacrylate copolymer (structural unit ratio derived from monomers: 22.9% by mass of structural units derived from styrene, 10% by mass of structural units derived from acrylonitrile, 67.1% by mass of structural units derived from methyl methacrylate) was obtained by the method described in Example 1. The refractive index of the obtained styrene / acrylonitrile / methyl methacrylate copolymer was 1.516, and the difference in refractive index from the rubbery polymer (r) was 0.000. Also, the weight average molecular weight was 110,000.

[0150] Vinyl copolymer (B-2’): In Example 23, except that the supply of various materials from the twin-screw extruder type feeder was not performed and the styrene / acrylonitrile / methyl methacrylate copolymer was produced by supply from the completely mixed polymerization tank, the styrene / acrylonitrile / methyl methacrylate copolymer (structural unit ratio derived from monomers: 22.9% by mass of structural units derived from styrene, 10% by mass of structural units derived from acrylonitrile, 67.1% by mass of structural units derived from methyl methacrylate) was obtained by the method described in Example 23. The refractive index of the obtained styrene / acrylonitrile / methyl methacrylate copolymer was 1.516, and the difference in refractive index from the rubbery polymer (r) was 0.000. Also, the weight average molecular weight was 98,500.

[0151] Vinyl copolymer (B-3’): In Example 24, a styrene / acrylonitrile / methyl methacrylate copolymer was produced by supply from a completely mixed polymerization tank without supplying various materials from a twin-screw extruder type feeder, in the same manner as described in Example 24. A styrene / acrylonitrile / methyl methacrylate copolymer (structural unit ratio derived from monomers: 22.4% by mass of structural units derived from styrene, 12.6% by mass of structural units derived from acrylonitrile, 65% by mass of structural units derived from methyl methacrylate) was obtained. The refractive index of the obtained styrene / acrylonitrile / methyl methacrylate copolymer was 1.516, and the difference in refractive index from the rubbery polymer (r) was 0.000. Also, the weight average molecular weight was 116,000.

[0152] Vinyl copolymer (B-4’): In Example 25, a styrene / acrylonitrile / methyl methacrylate copolymer was produced by supply from a completely mixed polymerization tank without supplying various materials from a twin-screw extruder type feeder, in the same manner as described in Example 25. A styrene / acrylonitrile / methyl methacrylate copolymer (structural unit ratio derived from monomers: 23.4% by mass of structural units derived from styrene, 7% by mass of structural units derived from acrylonitrile, 69.6% by mass of structural units derived from methyl methacrylate) was obtained. The refractive index of the obtained styrene / acrylonitrile / methyl methacrylate copolymer was 1.516, and the difference in refractive index from the rubbery polymer (r) was 0.000. Also, the weight average molecular weight was 110,000. (Production Example 3) Ester compound (C) Ester compound (C-1): Castor hardened oil, manufactured by Ito Oil Co., Ltd. (iodine value: 5 or less) (Production Example 4) Ester compound (D) Ester compound (D-1): Castor oil URIC H-30, manufactured by Ito Oil Co., Ltd. (Hydroxyl value: 155 - 165 mgKOH / g, viscosity: 660 - 720 mPa·s / 25°C) Ester compound (D-2): Castor oil-based polyester polyol URIC H-62, manufactured by Ito Seiyu Co., Ltd. (Hydroxyl value: 245 - 275 mgKOH / g, Viscosity: 240 - 290 mPa·s / 25°C) Ester compound (D-3): Castor oil-based polyester polyol URIC H-73X, manufactured by Ito Seiyu Co., Ltd. (Hydroxyl value: 260 - 280 mgKOH / g, Viscosity: 800 - 1200 mPa·s / 25°C) (Production Example 5) Compounds other than ester compound (C) and ester compound (D) (Other compound (F)) Other compound (F-1): Glycerol monostearate Rikemal S-100, manufactured by Riken Vitamin Co., Ltd. Other compound (F-2): Glycerol mono- and distearate Rikemal S-200, manufactured by Riken Vitamin Co., Ltd. Other compound (F-3): Glycerol mono 12-hydroxystearate Rikemal HC-100, manufactured by Riken Vitamin Co., Ltd. Other compound (F-4): Polyol ester LOXIOL G24, manufactured by Emery Oleochemicals (Hydroxyl value: 30 mgKOH / g or less) Other compound (F-5): Partial fatty acid ester of polyol LOXIOL VPA1726, manufactured by Emery Oleochemicals (Hydroxyl value: 430 - 500 mgKOH / g, Viscosity: 600 - 800 mPa·s / 25°C) Other compound (F-6): Partial fatty acid ester of glycerol LOXIOL P1141, manufactured by Emery Oleochemicals (Viscosity: 60 - 110 mPa·s / 25°C) Other compound (F-7): Pentaerythritol monostearate Exceparl PE-MS, manufactured by Kao Corporation (Production Example 6) Polydimethylsiloxane (E) E-1: GENIOPLAST GUM, manufactured by Asahi Kasei Wacker Co., Ltd. Preparation of resin dilution of polydimethylsiloxane gum (E-1) 30 kg (60 parts by mass) of graft copolymer (A-1), 15 kg (30 parts by mass) of vinyl copolymer (B-1'), and 5 kg (10 parts by mass) of polydimethylsiloxane gum (E-1) were put into a pressure twin-arm kneader (model: DS55-100MWH-H) manufactured by Moriyama Seisakusho. After mixing for 5 minutes at a stirring speed of 60 rpm under a pressure of 1 MPa, the pressure was released, and the mixture was mixed at normal pressure for 3 minutes, and then stirred and mixed again for 5 minutes under a pressure of 1 MPa to obtain a resin dilution of polydimethylsiloxane gum (E-1') in which polydimethylsiloxane gum (E-1) was attached to the surface of the solid matter of the graft copolymer (A-1) and the vinyl copolymer (B-1'). The processing temperature was 58°C or less.

[0153] Specific examples and comparative examples will be described below.

[0154] Each of the examples and comparative examples was carried out using a 2m evaporative dry distillation condenser (not shown) for monomer vapor, the basic configuration of which is shown in FIG. 1, and a helical ribbon blade. 3 A continuous bulk polymerization apparatus consisting of a complete mixing type polymerization tank 1, a single screw extruder type preheater 2, a twin screw extruder type demonomerizer 3, and a twin screw extruder type feeder 5 connected so as to side feed into a barrel section 1 / 3 lengthwise before the downstream (outlet) end of the demonomerizer was used to produce a thermoplastic resin composition. The details are as described in each Example and Comparative Example. The vinyl copolymer (B) is produced in the system (in the table, the vinyl copolymer (B) produced in Examples 1 to 22 and Example 26, and Comparative Examples 1 to 10 is represented as "vinyl copolymer (B-1)", the vinyl copolymer (B) produced in Example 23 is represented as "vinyl copolymer (B-2)", the vinyl copolymer (B) produced in Example 24 is represented as "vinyl copolymer (B-3)", and the vinyl copolymer (B) produced in Example 24 is represented as "vinyl copolymer (B-4)").

[0155] [Example 1] A monomer mixture (b) consisting of 22.9 parts by mass of styrene, 10 parts by mass of acrylonitrile, 67.1 parts by mass of methyl methacrylate, 0.21 part by mass of n-octyl mercaptan and 0.015 part by mass of 1,1-bis(t-butylperoxy)cyclohexane was continuously fed into a completely mixed polymerization tank at 150 kg / h, and continuously bulk polymerized while maintaining the polymerization temperature at 130°C and the pressure in the tank at 0.08 MPa. The polymerization rate of the polymerization reaction mixture at the outlet of the completely mixed polymerization tank was controlled to 70±5%.

[0156] Next, the polymerization reaction mixture was preheated by a single-screw extruder type preheater and then fed into a twin-screw extruder type monomer remover, and the unreacted monomer was recovered by vacuum evaporation from the vent port of the twin-screw extruder type monomer remover. The recovered unreacted monomer was continuously refluxed to the completely mixed polymerization tank. At a position 1 / 3 before the downstream end of the twin-screw extruder type monomer remover with respect to the total length, 150 kg / h (62 parts by mass) of the above-mentioned styrene / acrylonitrile / methyl methacrylate copolymer with an apparent polymerization rate of 99% or more was fed from a twin-screw extruder type feeder with 0.132 kg / h of 2,2'-methylenebis(4-methyl-6-t-butylphenol), which is a phenolic stabilizer, 0.288 kg / h of distearyl 3,3'-thiodipropionate, which is a sulfur-based stabilizer, 0.484 kg / h (0.2 part by mass) of an ester compound (C-1), and 91.9 kg / h (38 parts by mass) of a semi-molten state product of a graft copolymer (A-1). Also, from a liquid additive addition nozzle 2 / 3 before the downstream end of the twin-screw extruder type feeder (the position where the twin-screw extruder type feeder is connected to the twin-screw extruder type monomer remover) with respect to the total length, 0.968 kg / h (0.4 part by mass) of an ester compound (D-2) was fed into the twin-screw extruder type feeder using a liquid addition pump, and melt-kneaded with the styrene / acrylonitrile / methyl methacrylate copolymer in the twin-screw extruder type monomer remover. During the melt-kneading process, 2 kg / h of water was fed at a position 1 / 6 before the downstream end of the twin-screw extruder type monomer remover with respect to the total length. This water and other volatile components were removed by vacuum evaporation from a vent port installed further downstream of the twin-screw extruder type monomer remover. Thereafter, the melt-kneaded product was discharged in a strand shape and cut by a cutter to obtain pellets of a transparent thermoplastic resin composition.

[0157] [Example 2] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (D-2) was 1.935 kg / h (0.8 part by mass).

[0158] [Example 3] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass).

[0159] [Example 4] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (D-2) was 4.838 kg / h (2 parts by mass).

[0160] [Example 5] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (D-2) was 6.289 kg / h (2.6 parts by mass).

[0161] [Example 6] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 1.210 kg / h (0.5 part by mass).

[0162] [Example 7] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 1.210 kg / h (0.5 part by mass) and the supply rate of the ester compound (D-2) was 1.935 kg / h (0.8 part by mass).

[0163] [Example 8] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 1.210 kg / h (0.5 part by mass) and the supply rate of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass).

[0164] [Example 9] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of ester compound (C-1) was 1.210 kg / h (0.5 part by mass) and the supply rate of ester compound (D-2) was 4.838 kg / h (2 parts by mass).

[0165] [Example 10] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of ester compound (C-1) was 1.210 kg / h (0.5 part by mass) and the supply rate of ester compound (D-2) was 6.289 kg / h (2.6 parts by mass).

[0166] [Example 11] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of ester compound (C-1) was 1.693 kg / h (0.7 part by mass) and the supply rate of ester compound (D-2) was 0.968 kg / h (0.4 part by mass).

[0167] [Example 12] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of ester compound (C-1) was 1.693 kg / h (0.7 part by mass) and the supply rate of ester compound (D-2) was 1.935 kg / h (0.8 part by mass).

[0168] [Example 13] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1, except that the supply rate of ester compound (C-1) was 1.693 kg / h (0.7 part by mass) and the supply rate of ester compound (D-2) was 2.903 kg / h (1.2 parts by mass).

[0169] [Example 14] The supply amount of the ester compound (C-1) was 1.693 kg / h (0.7 parts by mass), and the supply amount of the ester compound (D-2) was 4.838 kg / h (2 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0170] [Example 15] The supply amount of the ester compound (C-1) was 1.693 kg / h (0.7 parts by mass), and the supply amount of the ester compound (D-2) was 6.289 kg / h (2.6 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0171] [Example 16] The supply amount of the ester compound (C-1) was 2.903 kg / h (1.2 parts by mass), and the supply amount of the ester compound (D-2) was 0.968 kg / h (0.4 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0172] [Example 17] The supply amount of the ester compound (C-1) was 2.903 kg / h (1.2 parts by mass), and the supply amount of the ester compound (D-2) was 1.935 kg / h (0.8 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0173] [Example 18] The supply amount of the ester compound (C-1) was 2.903 kg / h (1.2 parts by mass), and the supply amount of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0174] [Example 19] The supply amount of the ester compound (C-1) was 2.903 kg / h (1.2 parts by mass), and the supply amount of the ester compound (D-2) was 4.838 kg / h (2 parts by mass). Otherwise, in the same manner as in Example 1, transparent thermoplastic resin composition pellets were obtained.

[0175] [Example 20] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 2.903 kg / h (1.2 parts by mass) and the supply rate of the ester compound (D-2) was 6.289 kg / h (2.6 parts by mass).

[0176] [Example 21] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the supply rate of the ester compound was 1.693 kg / h (0.7 part by mass), the ester compound (D-2) was changed to the ester compound (D-1), and its supply rate was 2.903 kg / h (1.2 parts by mass).

[0177] [Example 22] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 1.693 kg / h (0.7 part by mass), the ester compound (D-2) was changed to the ester compound (D-3), and its supply rate was 2.903 kg / h (1.2 parts by mass).

[0178] [Example 23] The monomer mixture (b) was composed of 22.9 parts by mass of styrene, 10 parts by mass of acrylonitrile, 67.1 parts by mass of methyl methacrylate, 0.265 part by mass of n-octyl mercaptan, and 0.015 part by mass of 1,1-bis(t-butylperoxy)cyclohexane. Further, a transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the supply rate of the ester compound (C-1) was 1.693 kg / h (0.7 part by mass) and the supply rate of the ester compound ((D-2) was 2.903 kg / h (1.2 parts by mass).

[0179] [Example 24] The monomer mixture (b) was composed of 22.4 parts by mass of styrene, 12.6 parts by mass of acrylonitrile, 65 parts by mass of methyl methacrylate, 0.235 parts by mass of n-octyl mercaptan, and 0.015 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane. Further, except that the supply amount of the ester compound (C-1) was 1.693 kg / h (0.7 parts by mass) and the supply amount of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass), transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1.

[0180] [Example 25] The monomer mixture (b) was composed of 23.4 parts by mass of styrene, 7 parts by mass of acrylonitrile, 69.6 parts by mass of methyl methacrylate, 0.225 parts by mass of n-octyl mercaptan, and 0.015 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane. Further, except that the supply amount of the ester compound (C-1) was 1.693 kg / h (0.7 parts by mass) and the supply amount of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass), transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1.

[0181] [Example 26] Except that the supply amount of the ester compound (C-1) was 1.693 kg / h (0.7 parts by mass), the supply amount of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass), and further, a resin dilution (E-1’) of polydimethylsiloxane gum was supplied and its supply amount was 0.145 kg / h (0.06 parts by mass), transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1.

[0182] [Comparative Example 1] Except that the ester compound (C-1) was not supplied and the supply amount of the ester compound (D-2) was 2.903 kg / h (1.2 parts by mass), transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1.

[0183] [Comparative Example 2] The supply rate of the ester compound (C-1) was 1.693 kg / h (0.7 part by mass), and transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (D-2) was not supplied.

[0184] [Comparative Example 3] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (C-1) was not supplied and the ester compound (D-2) was not supplied.

[0185] [Comparative Example 4] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (D-2) was not supplied and a new other compound (F-1) was supplied, and the supply rate thereof was 2.903 kg / h (1.2 parts by mass).

[0186] [Comparative Example 5] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (D-2) was not supplied and a new other compound (F-2) was supplied, and the supply rate thereof was 2.903 kg / h (1.2 parts by mass).

[0187] [Comparative Example 6] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (D-2) was not supplied and a new other compound (F-3) was supplied, and the supply rate thereof was 2.903 kg / h (1.2 parts by mass).

[0188] [Comparative Example 7] Transparent thermoplastic resin composition pellets were obtained in the same manner as in Example 1 except that the ester compound (D-2) was not supplied and a new other compound (F-4) was supplied, and the supply rate thereof was 2.903 kg / h (1.2 parts by mass).

[0189] [Comparative Example 8] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the ester compound (D-2) was not supplied and another compound (F-5) was newly supplied at a supply rate of 2.903 kg / h (1.2 parts by mass).

[0190] [Comparative Example 9] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the ester compound (D-2) was not supplied and another compound (F-6) was newly supplied at a supply rate of 2.903 kg / h (1.2 parts by mass).

[0191] [Comparative Example 10] A transparent thermoplastic resin composition pellet was obtained in the same manner as in Example 1, except that the ester compound (D-2) was not supplied and another compound (F-7) was newly supplied at a supply rate of 2.903 kg / h (1.2 parts by mass).

[0192] The results were summarized in Tables 1 to 4.

[0193]

Table 1

[0194]

Table 2

[0195]

Table 3

[0196]

Table 4

[0197] As shown in the evaluation results of Examples 1 to 26, it was found that the transparent thermoplastic resin composition of the present embodiment can obtain a transparent thermoplastic resin composition having excellent impact resistance and fluidity while maintaining particularly high transparency.

[0198] Also, as shown in Examples 7, 8, 13, 14, and 22, the content of the ester compound (C) is 0.4 to 0.8 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl-based copolymer (B), and the content of the ester compound (D) is 0.8 to 2.4 parts by mass with respect to 100 parts by mass in total of the graft copolymer (A) and the vinyl-based copolymer (B). By setting the mass ratio of the ester compound (C) to the ester compound (D) to 25:75 to 40:60 and using an ester compound (D) having a hydroxyl value of 170 to 350 mgKOH / g, the balance among transparency, impact resistance, fluidity, mold release property, and mass productivity was particularly excellent.

[0199] In Comparative Example 1, since the ester compound (C) was not added, the impact resistance was poor. In Comparative Example 2, since the ester compound (D) was not added, the fluidity and mold release property were poor. In Comparative Example 3, since neither the ester compound (C) nor the ester compound (D) was added, the impact resistance and fluidity were poor. Comparative Examples 4 to 10 are examples in which the ester compound (C) and the ester compound (D) were not used in combination, and a compound different from these, that is, another compound (F), was used. However, a large amount of gel was generated and the mass productivity was poor.

Industrial Applicability

[0200] The transparent thermoplastic resin composition and molded article of the present embodiment can be widely used in applications such as home electric appliances, communication-related equipment, general sundries, and medical-related equipment.

Explanation of Signs

[0201] 1... Complete mixing type polymerization tank, 2... Single-screw extruder type preheater, 3... Twin-screw extruder type monomer remover, 4... Melt kneading zone, 5... Twin-screw extruder type feeder, 6... Discharge port, 7... Stirrer (helical ribbon blade), 8... Vent port, 9... Water inlet, 10... Final vent port, 11... Liquid additive addition nozzle

Claims

1. A transparent thermoplastic resin composition containing a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2), and a vinyl cyanide monomer (b3), the following ester compound (C), and the following ester compound (D). Ester compound (C): A hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid, and 85% by mass or more of the acids constituting the triglyceride is a hydrogenated product of ricinoleic acid. Ester compound (D): An ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid.

2. The transparent thermoplastic resin composition according to claim 1, wherein the hydroxyl value of the ester compound (D) is 170 to 350 mgKOH / g.

3. The content of the ester compound (C) is 0.4 to 0.8 parts by mass with respect to a total of 100 parts by mass of the graft copolymer (A) and the vinyl copolymer (B), and the content of the ester compound (D) is 0.6 to 2.4 parts by mass with respect to a total of 100 parts by mass of the graft copolymer (A) and the vinyl copolymer (B). The mass ratio ((C):(D)) of the ester compound (C) and the ester compound (D) is 25:75 to 40:

60. The transparent thermoplastic resin composition according to claim 1 or 2.

4. The transparent thermoplastic resin composition according to any one of claims 1 to 3, wherein the weight average molecular weight of the acetone-soluble component contained in the transparent thermoplastic resin composition is 100,000 to 120,000.

5. In the acetone-soluble component contained in the transparent thermoplastic resin composition, when the total of the structural unit derived from the (meth)acrylate monomer, the structural unit derived from the aromatic vinyl monomer, the structural unit derived from the vinyl cyanide monomer, and the structural unit derived from other vinyl monomers is 100% by mass, the content of the structural unit derived from the (meth)acrylate monomer is 50 to 82% by mass, the content of the structural unit derived from the aromatic vinyl monomer is 10 to 30% by mass, and the content of the structural unit derived from the vinyl cyanide monomer is 8 to 15% by mass. The transparent thermoplastic resin composition according to any one of claims 1 to 4.

6. In the acetone-soluble component contained in the transparent thermoplastic resin composition, when the weight average molecular weight of the acetone-soluble component is Mw1 and the content (% by mass) of the structural unit derived from the vinyl cyanide monomer contained in the acetone-soluble component when the mass of the acetone-soluble component is 100% by mass is W1, the value obtained by dividing Mw1 by W1 is 11,000 or more. The transparent thermoplastic resin composition according to any one of claims 1 to 5.

7. The transparent thermoplastic resin composition according to any one of claims 1 to 6, wherein the transparent thermoplastic resin composition further contains polydimethylsiloxane gum (E).

8. A process for producing a transparent thermoplastic resin composition, comprising a step of obtaining a graft copolymer (A) obtained by graft copolymerizing a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and a (meth)acrylate monomer (a2) in the presence of a rubbery polymer (r), a step of obtaining a vinyl copolymer (B) obtained by copolymerizing a monomer mixture (b) containing at least an aromatic vinyl monomer (b1), a (meth)acrylate monomer (b2), and a vinyl cyanide monomer (b3), and a step of blending the graft copolymer (A), the vinyl copolymer (B), the following ester compound (C), and the following ester compound (D). Ester compound (C): A hydrogenated product of a triglyceride of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid, and 85% by mass or more of the acids constituting the triglyceride is a hydrogenated product of ricinoleic acid. Ester compound (D): An ester of an acid selected from palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and dihydroxystearic acid and a polyhydric alcohol (provided that it has at least one ester bond with an unsaturated carboxylic acid), and 85% by mass or more of the acids constituting the ester is ricinoleic acid.

9. A molded article formed using the transparent thermoplastic resin composition according to any one of Claims 1 to 7.

10. A molded article formed using the transparent thermoplastic resin composition obtained by the production method according to Claim 8.

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