JPWO2016186121A1 - Transparent resin composition and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide a resin composition that is transparent and excellent in heat resistance and has no appearance defect during injection molding. 2 mm measured based on ASTM D1003, including a styrene resin (A) comprising a copolymer containing unsaturated dicarboxylic acid anhydride monomer units and a transparent resin (B) other than the styrene resin (A). A resin composition having a total light transmittance of 88% or more and a haze of 0.3% or less. Styrenic resin (A) contains 45 to 90% by mass of styrene monomer units, unsaturated dicarboxylic acid anhydride monomer units, (meth) acrylic acid monomer units, and (meth) acrylic acid esters. The copolymer is preferably a copolymer comprising 10 to 55% by mass of a monomer unit, and the transparent resin (B) is composed of a methacrylic resin, a methyl methacrylate-styrene copolymer, and a styrene-acrylonitrile copolymer. It is preferably composed of at least one selected.

Description

  The present invention relates to a transparent resin composition and a method for producing the same.

  Transparent resins such as methacrylic resin, methyl methacrylate-styrene copolymer and styrene-acrylonitrile copolymer are used in various applications such as home appliance parts, automobile parts, food packaging containers, building materials, sundries, etc. . Further, taking advantage of excellent transparency, it is also used as an optical member for liquid crystal displays such as an optical film, a diffusion plate, and a light guide plate. These transparent resins have good optical properties such as transparency, but have problems such as low heat resistance, and have been used only for limited applications. As a technique for improving the heat resistance of the transparent resin, there are Patent Documents 1 and 2.

WO2014 / 021264 WO2014 / 065129

  This invention makes it a subject to provide a novel transparent resin composition and its manufacturing method.

(1) A styrene resin (A) comprising a copolymer containing unsaturated dicarboxylic acid anhydride monomer units and a transparent resin (B) other than the styrene resin (A), and based on ASTM D1003 A resin composition having a measured total light transmittance of 2% thickness of 88% or more and a haze of 0.3% or less.
(2) The styrene resin (A) is 45 to 90% by mass of a styrene monomer unit, an unsaturated dicarboxylic acid anhydride monomer unit, a (meth) acrylic acid monomer unit, (meth). It is a copolymer comprising 10 to 55% by mass of at least one monomer unit selected from an acrylate monomer unit and other vinyl monomer units copolymerizable therewith. The resin composition according to (1).
(3) The transparent resin (B) comprises at least one selected from a methacrylic resin, a methyl methacrylate-styrene copolymer, and a styrene-acrylonitrile copolymer (1) or (2 ).
(4) The content of the styrene-based resin (A) is 5 to 50% by mass, and the content of the transparent resin (B) is 95 to 50% by mass, and any one of (1) to (3) The resin composition described in 1.
(5) According to JIS K7206, the Vicat softening temperature of the styrene resin (A) obtained at a load of 50 N and a heating rate of 50 ° C./hour is 110 ° C. or higher (1) to (4) The resin composition in any one of.
(6) A molded product obtained by injection molding the resin composition according to any one of (1) to (5).
(7) Separate quantitative feeders for the styrene resin (A) comprising a copolymer containing unsaturated dicarboxylic acid anhydride monomer units and the transparent resin (B) other than the styrene resin (A). The manufacturing method of a resin composition provided with the process of using and supplying to an extruder and melt-kneading.
(8) Styrene resin (A) is 45-90 mass% of styrene monomer units, unsaturated dicarboxylic acid anhydride monomer units, (meth) acrylic acid monomer units, (meth). It is a copolymer comprising 10 to 55% by mass of at least one monomer unit selected from an acrylate monomer unit and other vinyl monomer units copolymerizable therewith. The manufacturing method of the resin composition as described in (7).
(9) The transparent resin (B) comprises at least one selected from a methacrylic resin, a methyl methacrylate-styrene copolymer, and a styrene-acrylonitrile copolymer (7) or (8 The manufacturing method of the resin composition as described in).
(10) The content of the styrenic resin (A) is 5 to 50% by mass, and the content of the transparent resin (B) is 95 to 50% by mass, any one of (7) to (9) The manufacturing method of the resin composition as described in any one of.
(11) According to JIS K7206, the Vicat softening temperature of the styrene-based resin (A) obtained at a load of 50 N and a heating rate of 50 ° C./hour is 110 ° C. or higher (7) to (10) The manufacturing method of the resin composition in any one of.

  Since the resin composition of the present invention is excellent in transparency, it is useful for parts of home appliances, automobile parts, building materials, optical members, food containers, etc. that are required to have heat resistance and good appearance, particularly at the time of injection molding. A molded article having no appearance defect is obtained.

<Explanation of terms>
In the present specification, for example, the description “A to B” means that it is A or more and B or less.

  Hereinafter, embodiments of the present invention will be described in detail.

  The transparent resin composition of the present invention comprises a styrene resin (A) comprising a copolymer containing unsaturated dicarboxylic acid anhydride monomer units, and a transparent resin (B) other than the styrene resin (A). The total light transmittance with a thickness of 2 mm measured based on ASTM D1003 is 88% or more and the haze is 0.3% or less. Such a resin composition is obtained by supplying the styrene resin (A) and the transparent resin (B) to an extruder using separate quantitative feeders and melt-kneading them.

  Styrenic resin (A) is a copolymer containing a styrene monomer unit and an unsaturated dicarboxylic anhydride monomer unit, a (meth) acrylic acid monomer unit, (meth) It may also contain at least one monomer unit selected from an acrylate ester monomer unit and other vinyl monomers copolymerizable therewith. Examples of the styrene resin (A) include styrene-methyl methacrylate-maleic anhydride copolymer, styrene-maleic anhydride copolymer, and the like.

  Styrene monomers are styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, ethyl styrene, pt-butyl styrene, α-methyl styrene, α-methyl. -P-methylstyrene and the like. Of these, styrene is preferred. Styrenic monomers may be used alone or in combination of two or more.

  The unsaturated dicarboxylic acid anhydride monomer includes maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic acid anhydride, and the like. Of these, maleic anhydride is preferred. The unsaturated dicarboxylic acid anhydride monomer may be used alone or in combination of two or more.

  The (meth) acrylic acid monomer unit is acrylic acid, methacrylic acid or the like, and among these, methacrylic acid is preferable.

  The (meth) acrylic acid ester monomer unit is, for example, a single amount of each methacrylic acid ester such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, dicyclopentanyl methacrylate, and isobornyl methacrylate. And acrylate monomers such as methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-methylhexyl acrylate, 2-ethylhexyl acrylate, and decyl acrylate. Among these, a methyl methacrylate unit is preferable. The (meth) acrylic acid ester monomer may be used alone or in combination of two or more.

  As other copolymerizable vinyl monomers, acrylonitrile monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile and fumaronitrile, and N-substituted maleimide monomers such as N-phenylmaleimide may be used. it can.

The structural unit of the styrene resin (A) is 45 to 90% by mass of a styrene monomer unit, an unsaturated dicarboxylic acid anhydride monomer unit, a (meth) acrylic acid monomer unit, (meth). It is preferably 10 to 55% by mass of at least one monomer selected from acrylic ester monomer units and other vinyl monomers copolymerizable therewith. It is more preferably 45 to 85% by mass of styrene monomer units, 10 to 30% by mass of unsaturated dicarboxylic anhydride monomer units, and 5 to 45% by mass of (meth) acrylic acid ester monomer units. Preferably, it has an excellent balance between heat resistance and strength. The composition analysis of each monomer unit is a value measured by the C-13 NMR method under the measurement conditions described below.
Device name: FT-NMR AVANCE300 (manufactured by BRUKER)
Solvent: Deuterated chloroform Concentration: 14% by mass
Temperature: 27 ° C
Integration count: 8000 times

The weight average molecular weight (Mw) of the styrene resin (A) is preferably 50,000 to 300,000, and more preferably 100,000 to 250,000. A weight average molecular weight (Mw) in the range of 50,000 to 300,000 is preferable because of a good balance between strength and moldability. The weight average molecular weight (Mw) can be controlled by the polymerization temperature and polymerization time in the polymerization process, the type and addition amount of the polymerization initiator, the type and addition amount of the chain transfer agent, the type and amount of the solvent used during the polymerization, and the like. it can. The weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC), and is a value measured under the measurement conditions described below.
Device name: SYSTEM-21 Shodex (manufactured by Showa Denko)
Column: 3 series PL gel MIXED-B Temperature: 40 ° C
Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2% by mass
Calibration curve: Prepared using standard polystyrene (PS) (manufactured by PL).

  A known method can be adopted as a polymerization method of the styrene resin (A). The radical polymerization method is preferable because it is a simple process and excellent in productivity.

  As a method for producing the styrene resin (A), a known method can be employed. For example, it can be produced by solution polymerization, bulk polymerization or the like. Moreover, any of a continuous method and a batch method is applicable. In the copolymerization of styrene monomer and unsaturated dicarboxylic acid anhydride monomer, the alternating copolymerization is high, so the copolymerization can be achieved by polymerizing while adding unsaturated dicarboxylic acid anhydride monomer separately. Solution polymerization is preferred because the polymerization composition can be made uniform. The solvent for the solution polymerization is preferably non-polymerizable from the viewpoint that it is difficult to produce by-products and has few adverse effects. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, tetrahydrofuran, 1,4- And ethers such as dioxane, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and the like.

  In the solution polymerization or bulk polymerization of the styrene resin (A), a polymerization initiator and a chain transfer agent can be used, and the polymerization temperature is preferably in the range of 70 to 180 ° C. Examples of the polymerization initiator include dibenzoyl peroxide, t-butylperoxybenzoate, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, t-butylperoxyisopropyl monocarbonate, and t-butylperoxide. Peroxides such as oxy-2-ethylhexanoate, t-butylperoxyacetate, dicumyl peroxide, ethyl-3,3-di- (t-butylperoxy) butyrate, azobisisobutyronitrile, These are azo compounds such as azobiscyclohexanecarbonitrile, azobismethylpropionitrile, azobismethylbutyronitrile, etc., and these may be used alone or in combination. Two or more of these polymerization initiators can be used in combination. Among these, it is preferable to use an organic peroxide having a 10-hour half-life temperature of 70 to 110 ° C. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene and the like.

  As a devolatilization method for removing volatile components such as unreacted monomers and a solvent used for solution polymerization from the solution after completion of the polymerization of the styrene resin (A), a known method can be adopted. For example, a vacuum devolatilization tank with a preheater or a vented devolatilization extruder can be used. The devolatilized molten styrene resin (A) is transferred to a granulation process, extruded into a strand shape from a porous die, and processed into a pellet shape by a cold cut method, an air hot cut method, or an underwater hot cut method. be able to.

  From the viewpoint of transparency, the total light transmittance of 2 mm thickness measured based on ASTM D1003 of the styrenic resin (A) in the present invention is preferably 88% or more, and Haze is preferably 0.5% or less, more preferably. The total light transmittance is 90% or more, and the haze is 0.3% or less. By polymerizing the copolymer composition distribution to be small, a styrene resin (A) excellent in transparency can be obtained.

  In accordance with JIS K7206, the Vicat softening temperature of the styrene-based resin (A) obtained at a load of 50 N and a heating rate of 50 ° C./hour is preferably 115 ° C. or higher, more preferably 125 ° C. or higher. The higher the Vicat softening temperature, the higher the effect of improving the heat resistance of the methacrylic resin, which is preferable. The Vicat softening temperature of the styrenic resin (A) can be adjusted by the content of heat-resistant monomers such as unsaturated dicarboxylic acid anhydride monomer units and (meth) acrylic acid monomer units. .

  The transparent resin (B) is a resin that is transparent and compatible with the styrene resin (A) at the temperature at the time of melt kneading and molding. For example, a methacrylic resin, a methyl methacrylate-styrene copolymer And styrene-acrylonitrile copolymers. Among these, a methacrylic resin is preferable because of its excellent optical properties. The constituent units of the methyl methacrylate-styrene copolymer system copolymer are preferably 70 to 97% by mass of methyl methacrylate units and 3 to 30% by mass of styrene. The structural unit of the styrene-acrylonitrile copolymer is preferably 70 to 85% by mass of styrene and 15 to 30% by mass of acrylonitrile. As the methacrylic resin, methyl methacrylate-styrene copolymer, and styrene-acrylonitrile copolymer, commercially available general ones can be used. The shape may be pellets or beads, but it is preferable that the particle size distribution is uniform.

  From the viewpoint of transparency, the total light transmittance of 2 mm thickness measured based on ASTM D1003 of the transparent resin (B) in the present invention is preferably 88% or more, and Haze is preferably 0.5% or less, more preferably, The total light transmittance is 90% or more and Haze is 0.3% or less.

  It is necessary to quantitatively supply the styrene resin (A) and the transparent resin (B) to the extruder using separate quantitative feeders. As long as separate metering feeders are used for each resin, the raw material charging port of the extruder may be provided in one place, or a plurality may be provided depending on the number of metering feeders. After dry blending the styrene resin (A) and the transparent resin (B), the hopper is fed to the extruder provided at one place of the raw material charging port, or the extruder is provided with only one quantitative feeder. In the method of supplying the blended resin in a lump, when the obtained resin composition is injection-molded, fluctuation occurs inside the molded body, resulting in poor appearance. This fluctuation is due to non-uniformity of the refractive index, and occurs when the blending ratio of the styrene resin (A) and the transparent resin (B) varies in the resin composition. In injection molding, the molten resin that flows in from the gate fills the mold while spreading like a balloon in the flow direction. Observed. When the fluctuation becomes noticeable, it may appear streaks. This fluctuation is sometimes called striae. In the method of supplying to the extruder in a lump after dry blending, segregation occurs due to the difference in shape and density between the styrene resin (A) and the transparent resin (B), and the blending ratio fluctuates. End up.

  Two or more types of styrene resin (A) or transparent resin (B) can be used as long as they are compatible with each other, but it is necessary to use different feeders for each. The supply ratio of the styrene resin (A) and the transparent resin (B) may be arbitrarily determined within a range in which both are compatible.

  A feeder is a device that supplies pellet or bead-shaped raw material resin to an extruder, and a known material can be used. However, since quantitative raw material supply is essential, a quantitative feeder must be used. . Examples of the quantitative feeder include loss-in-weight feeders, positive displacement feeders, and heavy-weight belt feeders. Loss-in-weight feeders are particularly preferable, and supply accuracy is preferably within ± 1%. . It is preferable to control each feeder in conjunction with each other, and it is preferable to perform control so that the supply amount of other feeders is a constant ratio with respect to the supply amount of the main feeder.

  The raw material resin supplied to the extruder is melted and kneaded continuously in the extruder, extruded into a strand form from a perforated die, a pellet-shaped resin composition by a cold cut method, an air hot cut method, or an underwater hot cut method. Is obtained. A well-known apparatus can be used for an extruder, for example, a twin screw extruder, a single screw extruder, a multi screw extruder, a continuous kneader with a twin screw rotor, etc. are mentioned.

  The resin composition may contain additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, a plasticizer, a lubricant, a dye, and a flame retardant, as long as the transparency is not impaired.

  The content of the styrene resin (A) and the transparent resin (B) in the resin composition is preferably 5 to 50% by mass and 95 to 50% by mass, respectively, more preferably 15 to 50% by mass and 85%, respectively. -50% by mass, more preferably 15-35% by mass and 85-65% by mass, respectively. By setting the contents of the styrene resin (A) and the transparent resin (B) to 5 to 50% by mass and 95 to 50% by mass, respectively, a transparent resin composition having an excellent balance between heat resistance and surface hardness is obtained. It is done.

  From the viewpoint of transparency, the 2 mm-thick total light transmittance measured based on ASTM D1003 of the resin composition in the present invention is 88% or more, and Haze is 0.3% or less. The total light transmittance is preferably 90% or more. The haze is preferably 0.2% or less. When the styrene resin (A) and the transparent resin (B) are compatible with each other and are produced by the method of the present invention, a resin composition having excellent transparency can be obtained.

  According to JIS K7206, the Vicat softening temperature of the resin composition determined at a load of 50 N and a heating rate of 50 ° C./hour is preferably 110 ° C. or higher, more preferably 113 ° C. or higher, and even more preferably 115 ° C. That's it. The higher the Vicat softening temperature, the more members that can be applied.

  A known method can be adopted as a method for molding the resin composition. For example, injection molding, press molding, sheet molding and the like can be mentioned. In particular, injection molding is preferable because no fluctuating molding defects occur inside the molded body. Fluctuation-like molding defects are particularly noticeable with injection molded articles having a large thickness, but the resin composition of the present invention does not cause poor appearance even with an injection molded article having a large thickness.

  Hereinafter, although detailed content is demonstrated using an Example, this invention is not limited to a following example.

<Styrene resin (A)>
<Production Example of Styrenic Resin (A-1)>
20% maleic anhydride solution dissolved in methyl isobutyl ketone so that maleic anhydride has a concentration of 20% by mass and methyl so that t-butylperoxy-2-ethylhexanoate is 2% by mass. A 2% t-butyl peroxy-2-ethylhexanoate solution diluted in isobutyl ketone was prepared in advance and used for the polymerization. A 120-liter autoclave equipped with a stirrer is charged with 3.6 kg of a 20% maleic anhydride solution, 24 kg of styrene, 8.8 kg of methyl methacrylate and 20 g of t-dodecyl mercaptan, and the gas phase portion is replaced with nitrogen gas. Then, the temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, 2.7 kg / hour of 20% maleic anhydride solution and 375 g / hour of 2% t-butylperoxy-2-ethylhexanoate solution were respectively added. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a heating rate of 8 ° C./hour while maintaining the addition rate of 2.7 kg / hour. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 32.4 kg. After the temperature increase, the polymerization was terminated by maintaining 120 ° C. for 1 hour. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A resin (A-1) was obtained. The obtained A-1 was subjected to composition analysis by C-13 NMR method. Furthermore, molecular weight measurement was performed with a GPC apparatus. As a result of composition analysis, the structural unit of A-1 was 60% by mass of a styrene monomer unit, 22% of a methyl methacrylate monomer unit, and 18% by mass of a maleic anhydride monomer unit. Moreover, the weight average molecular weight (Mw) was 160,000, and Mw / Mn which is a ratio with the number average molecular weight (Mn) was 2.4. The 2 mmt specular plate molded by injection molding had a total light transmittance of 91% and a haze of 0.2%. In accordance with JIS K7206, the Vicat softening temperature determined at a load of 50 N and a heating rate of 50 ° C./hour was 133 ° C.

<Production Example of Styrenic Resin (A-2)>
A 20% maleic anhydride solution and a 2% t-butylperoxy-2-ethylhexanoate solution were prepared in the same manner as A-1. A 120 liter autoclave equipped with a stirrer was charged with 2.8 kg of a 20% maleic anhydride solution, 25.6 kg of styrene, 8.8 kg of methyl methacrylate, and 20 g of t-dodecyl mercaptan, and the gas phase portion was nitrogen gas. The temperature was raised to 88 ° C. over 40 minutes with stirring. While maintaining 88 ° C. after the temperature rise, 2.1% / hour of 20% maleic anhydride solution and 500 g / hour of 2% t-butylperoxy-2-ethylhexanoate solution were respectively added. The addition continued continuously over 8 hours. Thereafter, the addition of the 2% t-butylperoxy-2-ethylhexanoate solution was stopped, and 40 g of t-butylperoxyisopropyl monocarbonate was added. The 20% maleic anhydride solution was heated to 120 ° C. over 4 hours at a temperature rising rate of 8 ° C./hour while maintaining the addition rate of 2.1 kg / hour as it was. The addition of the 20% maleic anhydride solution was stopped when the amount of addition reached 25.2 kg. After the temperature rise, the polymerization liquid which has been held at 120 ° C. for 1 hour to finish the polymerization is continuously fed to a twin-screw devolatilizing extruder using a gear pump to remove methyl isobutyl ketone and a small amount of unreacted monomer. The styrene resin (A-2) in the form of pellets was obtained by volatilization treatment and extrusion cutting into strands. About obtained A-2, the composition analysis, the molecular weight, and the total light transmittance were measured like A-1. As a result of composition analysis, the structural unit of A-2 was styrene monomer unit 64% by mass, methyl methacrylate monomer unit 22%, and maleic anhydride monomer unit 14% by mass. Moreover, the weight average molecular weight (Mw) was 170,000 and Mw / Mn which is a ratio with the number average molecular weight (Mn) was 2.6. The 2 mmt specular plate molded by injection molding had a total light transmittance of 91% and a haze of 0.2%. In accordance with JIS K7206, the Vicat softening temperature obtained at a load of 50 N and a heating rate of 50 ° C./hour was 126 ° C.

<Production Example of Styrene Resin (A-3)>
A 25% maleic anhydride solution dissolved in methyl isobutyl ketone so that the concentration of maleic anhydride was 25% by mass was prepared in advance and used for polymerization. A 2% t-butylperoxy-2-ethylhexanonate solution was prepared in the same manner as in Production Example (A-1) and used for polymerization. A 120-liter autoclave equipped with a stirrer was charged with 3.52 kg of a 25% maleic anhydride solution, 24 kg of styrene, 7.2 kg of methyl methacrylate, and 20 g of t-dodecyl mercaptan, and the gas phase was replaced with nitrogen gas. The temperature was raised to 92 ° C. over 40 minutes with stirring. While maintaining the temperature at 92 ° C. after the temperature rise, a 25% maleic acid non-aqueous solution and a 2% t-butylperoxy-2-ethylhexanoate solution were each continuously added. The 25% maleic anhydride solution was 3.96 kg / hour from the 4th hour to the start of the addition, 3.17 kg / hour from the 4th to the 7th hour, and 1.58 kg from the 7th to the 10th hour. / Hour, the addition speed was changed stepwise so that the addition speed was 0.54 kg / hour from the 10th hour to the 13th hour, and a total of 31.71 kg was added. The 2% t-butylperoxy-2-ethylhexanoate solution has a rate of addition of 0.24 kg / hour from the start of the addition to 7 hours and 0.39 kg / hour from the 7th hour to the 13th hour. The addition speed was changed stepwise so that a total of 4.02 kg was added. The polymerization temperature is maintained at 92 ° C. until 7 hours from the start of the addition, and then heated to 116 ° C. over 6 hours at a rate of 4 ° C./hour, and further maintained at 116 ° C. for 1 hour. Was terminated. The polymerization liquid is continuously fed to a twin-screw devolatilizing extruder using a gear pump, and styrene in the form of pellets is formed by devolatilizing methyl isobutyl ketone and a small amount of unreacted monomer, and extruding and cutting into strands. A resin (A-3) was obtained. About A-3 obtained, the composition analysis, molecular weight, and total light transmittance were measured similarly to A-1. As a result of composition analysis, the structural unit of A-3 was 60% by mass of a styrene monomer unit, 18% of a methyl methacrylate monomer unit, and 22% by mass of a maleic anhydride monomer unit. Moreover, the weight average molecular weight (Mw) was 160,000, and Mw / Mn which is a ratio with the number average molecular weight (Mn) was 2.4. The 2 mmt specular plate molded by injection molding had a total light transmittance of 90% and a haze of 0.2%. In accordance with JIS K7206, the Vicat softening temperature determined at a load of 50 N and a heating rate of 50 ° C./hour was 142 ° C.

<Transparent resin (B)>
<Transparent resin (B-1)>
A methacrylic resin (Acrypet VH manufactured by Mitsubishi Rayon Co., Ltd.) was used as the transparent resin (B-1). In accordance with JIS K7206, the Vicat softening temperature determined at a load of 50 N and a heating rate of 50 ° C./hour was 108 ° C.

<Transparent resin (B-2)>
As the transparent resin (B-2), a methyl methacrylate-styrene copolymer having 80% by mass of methyl methacrylate units and 20% by mass of styrene units was used. In accordance with JIS K7206, the Vicat softening temperature determined at a load of 50 N and a heating rate of 50 ° C./hour was 104 ° C.

<Examples 1-6, Comparative Examples 1-6>
Styrenic resin (A) and transparent resin (B) were blended as shown in Table 1 and melt kneaded using an extruder to obtain a resin composition. In Examples 1 to 6, the styrene resin (A) and the transparent resin (B) were supplied to the extruder using separate quantitative feeders. The supply amount of the transparent resin (B) was set to 15 kg / hr in Examples 1 to 3, 19 kg / hr in Example 4, 10 kg / hr in Example 5, 15 kg / hr in Example 6, and styrene resin ( The supply amount of A) was controlled so as to be the mixing ratio shown in Table 1 (total supply amount was 20 kg / hr). As the quantitative feeder, a loss-in-weight feeder (CE-W-1 manufactured by Kubota Corporation) was used. In Comparative Examples 1 to 6, pellets of styrene resin (A) and transparent resin (B) were dry blended at the blending ratio shown in Table 1, and then supplied to the extruder using the same feeder. The supply amount of the dry blended pellets was set to 20 kg / hr. As the extruder, a twin screw extruder (TEM-26SX, manufactured by Toshiba Machine Co., Ltd.) was used, the cylinder temperature was set to 240 ° C., and the screw rotation speed was set to 250 rpm. After melt-kneading with an extruder, a pellet-shaped resin composition was obtained by extrusion from a perforated die into a strand and a cold cut method. The following evaluation was performed about the obtained resin composition. The evaluation results are shown in Table 1.

(Vicat softening point)
The Vicat softening point was measured according to JIS K7206: 1999 using 50 specimens (load 50 N, temperature rising rate 50 ° C./hour) with a test piece of 10 mm × 10 mm and a thickness of 4 mm. In addition, the measuring machine used the Toyo Seiki Seisakusho Co., Ltd. HDT & VSPT test apparatus.

(Total light transmittance, Haze)
The total light transmittance and Haze were 90 mm in length, 55 mm in width, and 2 mm in thickness formed using an injection molding machine (IS-50EPN, manufactured by Toshiba Machine Co., Ltd.) under molding conditions of a cylinder temperature of 240 ° C. and a mold temperature of 70 ° C. The mirror surface plate was measured using a haze meter (NDH-1001DP type, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with ASTM D1003.

(Existence of appearance defects)
Using an injection molding machine (J140AD-180H manufactured by Nippon Steel Co., Ltd.), a mirror surface plate having a length of 127 mm, a width of 127 mm, and a thickness of 6 mm was molded under the molding conditions of a cylinder temperature of 250 ° C. and a mold temperature of 70 ° C. The presence or absence of appearance defects was confirmed.

  In an example in which the styrene resin (A) and the transparent resin (B) are separately fed, there is no fluctuation-like appearance defect, and the appearance, transparency, and heat resistance are excellent. On the other hand, a fluctuation-like appearance defect occurs in the comparative example that is batch fed by dry blending.

  Since the resin composition of the present invention is transparent, excellent in appearance, and excellent in heat resistance, it is useful for home appliance parts, automobile parts, building materials, optical members, food containers, and the like. In particular, there is no appearance defect in injection molding, and it can be suitably used.

Claims (11)

2 mm measured based on ASTM D1003, including a styrene resin (A) comprising a copolymer containing unsaturated dicarboxylic acid anhydride monomer units and a transparent resin (B) other than the styrene resin (A). A resin composition having a total light transmittance of thickness of 88% or more and a haze of 0.3% or less. Styrene resin (A) is 45-90 mass% of styrene monomer units, unsaturated dicarboxylic acid anhydride monomer units, (meth) acrylic acid monomer units, (meth) acrylic acid esters. A copolymer comprising 10 to 55% by mass of at least one monomer unit selected from a monomer unit and other vinyl monomer units copolymerizable therewith. Item 2. The resin composition according to Item 1. The transparent resin (B) is composed of at least one selected from a methacrylic resin, a methyl methacrylate-styrene copolymer, and a styrene-acrylonitrile copolymer. Resin composition. The content of the styrenic resin (A) is 5 to 50% by mass, and the content of the transparent resin (B) is 95 to 50% by mass, according to any one of claims 1 to 3. The resin composition as described. The Vicat softening temperature of the styrene-based resin (A) obtained at a load of 50 N and a heating rate of 50 ° C / hour in accordance with JIS K7206 is 110 ° C or higher. 2. The resin composition according to item 1. The molded object obtained by injection-molding the resin composition of any one of Claims 1-5. Extrude a styrene resin (A) composed of a copolymer containing unsaturated dicarboxylic acid anhydride monomer units and a transparent resin (B) other than the styrene resin (A) using separate quantitative feeders. The manufacturing method of a resin composition provided with the process of supplying to a machine and melt-kneading. Styrene resin (A) is 45-90 mass% of styrene monomer units, unsaturated dicarboxylic acid anhydride monomer units, (meth) acrylic acid monomer units, (meth) acrylic acid esters. A copolymer comprising 10 to 55% by mass of at least one monomer unit selected from a monomer unit and other vinyl monomer units copolymerizable therewith. Item 8. A method for producing a resin composition according to Item 7. The transparent resin (B) is composed of at least one selected from a methacrylic resin, a methyl methacrylate-styrene copolymer, and a styrene-acrylonitrile copolymer. A method for producing the resin composition. The content of the styrene-based resin (A) is 5 to 50% by mass, and the content of the transparent resin (B) is 95 to 50% by mass, according to any one of claims 7 to 9. The manufacturing method of the resin composition of description. The Vicat softening temperature of the styrene-based resin (A) obtained at a load of 50 N and a heating rate of 50 ° C / hour in accordance with JIS K7206 is 110 ° C or higher. 2. A method for producing a resin composition according to item 1.