Method for producing a heat-resistant resin composition

Abstract

The objective of this invention is to provide a method for manufacturing a heat-resistant resin composition with excellent dispersibility of a maleimide copolymer. According to the invention, a method for manufacturing a heat-resistant resin composition is provided, comprising a step of melt-blending a maleimide copolymer (A) and a resin (B) selected from at least one of ABS resin, ASA resin, AES resin, and SAN resin using an extruder, wherein the shear rate is 120 / sec, and the ratio of the melt viscosity of the maleimide copolymer (A) to the melt viscosity of the resin (B) at the cylinder temperature of the blending section of the extruder is 1.0 or more and less than 3.4.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a heat-resistant resin composition of maleimide copolymer with excellent dispersibility. Background Technology

[0002] ABS resin is a thermoplastic resin mainly composed of acrylonitrile, butadiene, and styrene. Due to its excellent mechanical strength, appearance, chemical resistance, and moldability, it is widely used in automobiles, home appliances, office automation equipment, building materials, and daily necessities. However, in applications requiring high heat resistance, such as automotive interior materials, its heat resistance may be insufficient. As a technique to improve heat resistance, maleimide copolymers or α-methylstyrene copolymers can be used (Patent Documents 1, 2). Furthermore, in recent years, progress has been made in increasing the torque and screw depth of twin-screw extruders, making high discharge rates possible.

[0003] [Existing Technical Documents]

[0004] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2003-41080

[0006] [Patent Document 2] Publication No. WO2010 / 082617 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The objective of this invention is to provide a method for manufacturing a heat-resistant resin composition with excellent dispersibility of maleimide copolymers.

[0009] Solution for solving the problem

[0010] (1) A method for manufacturing a heat-resistant resin composition, comprising a step of melt-blending a maleimide copolymer (A) and a resin (B) selected from at least one of ABS resin, ASA resin, AES resin, and SAN resin using an extruder, wherein the shear rate is 120 / sec and the ratio of the melt viscosity of the maleimide copolymer (A) to the melt viscosity of the resin (B) is 1.0 or more and less than 3.4 at the cylinder temperature of the blending section of the extruder.

[0011] (2) The method for manufacturing the heat-resistant resin composition as described in (1), wherein the melt-blending process is carried out in the presence of an antioxidant (C).

[0012] (3) A method for manufacturing a heat-resistant resin composition as described in (1) or (2), wherein the extruder is a twin-shaft extruder.

[0013] (4) The method for manufacturing the heat-resistant resin composition as described in (3), wherein the screw groove ratio in the mixing section of the above-mentioned twin-screw extruder is 1.55 or more.

[0014] The effects of the invention

[0015] The resin composition obtained by the manufacturing method of the heat-resistant resin composition of the present invention exhibits excellent dispersibility of the maleimide copolymer, and therefore also exhibits sufficient dispersibility in resins such as ABS resin. Thus, even under high discharge conditions using a deep-slot screw with slightly poor dispersibility, molded articles with good dispersion of the maleimide copolymer and no appearance defects can be obtained. Attached Figure Description

[0016] Figure 1 This is a screw configuration diagram of a biaxial extrusion apparatus according to an embodiment of the present invention. Detailed Implementation

[0017] <Terminology Explanation>

[0018] In this specification, terms such as "A~B" refer to A and below B.

[0019] The embodiments of the present invention will be described in detail below. The embodiments shown below can be combined with each other.

[0020] The resin composition of the present invention is a heat-resistant resin composition obtained by melt-blending maleimide copolymer (A) and resin (B) selected from at least one of SAN resin, ABS resin, ASA resin, and AES resin using an extruder.

[0021] The maleimide copolymer (A) is a copolymer containing maleimide monomer units and styrene monomer units. In this invention, it may also contain acrylonitrile monomer units and unsaturated dicarboxylic anhydride monomer units.

[0022] Maleimide monomer units include, for example, N-alkylmaleimides such as N-methylmaleimide, N-butylmaleimide, and N-cyclohexylmaleimide; and N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, and N-tribromophenylmaleimide. N-phenylmaleimide is preferred. Maleimide monomer units can be used alone or in combination of two or more. For example, maleimide monomer units can be derived from a source composed of maleimide monomers. Alternatively, they can be obtained by imidizing a source composed of unsaturated dicarboxylic acid monomer units using ammonia or a primary amine.

[0023] The maleimide copolymer (A) preferably contains 30-70% by mass of maleimide monomer units per 100% by mass, more preferably 35-60% by mass. Specifically, the content of maleimide monomer units is, for example, 30, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 50, 55, 60, or 70% by mass, or may be within any range of two exemplified values. If the content of maleimide monomer units is within this range, compatibility with at least one resin (B) selected below from ABS, ASA, AES, and SAN resins is improved, and the resin composition exhibits excellent impact strength. The content of maleimide monomer units is a value measured by 13C-NMR.

[0024] The styrene-based monomer units include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, and α-methyl-p-methylstyrene. Styrene is preferred. Styrene-based monomer units can be used alone or in combination of two or more.

[0025] The maleimide copolymer (A) preferably contains 20-60% by mass of styrene monomer units per 100% by mass, more preferably 35-55% by mass. Specifically, for example, it is 20, 30, 40, 45, 46, 47, 48, 49, 50, 55, or 60% by mass, or it can be within any range of two of the exemplified values. If the content of styrene monomer units is within this range, the compatibility with at least one resin (B) selected below from ABS resin, ASA resin, AES resin, and SAN resin can be improved, and the impact strength of the resin composition is excellent. The content of styrene monomer units is a value measured by 13C-NMR.

[0026] Acrylonitrile monomer units include acrylonitrile, methacrylonitrile, ethyl acrylonitrile, fumaric acid, etc. Acrylonitrile is preferred. Acrylonitrile monomer units can be used alone or in combination of two or more.

[0027] The maleimide copolymer (A) preferably contains 0 to 20% by mass of acrylonitrile monomer units per 100% by mass, more preferably 0 to 15% by mass. Specifically, for example, it is 0, 5, 6, 7, 8, 9, 10, 15, or 20% by mass, or it can be within any range of two of the exemplified values. If the content of acrylonitrile monomer units is within this range, the resin composition exhibits excellent chemical resistance. The content of acrylonitrile monomer units is a value determined using 13C-NMR.

[0028] The unsaturated dicarboxylic acid anhydride monomer units include maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic anhydride, etc., with maleic anhydride being the preferred choice. Unsaturated dicarboxylic acid anhydride monomer units can be used alone or in combination of two or more.

[0029] The maleimide copolymer (A) preferably contains 0-10% by mass of unsaturated dicarboxylic anhydride monomer units per 100% by mass, more preferably 0-5% by mass. Specifically, for example, it is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10% by mass, or any range between two of the exemplified values. If the content of unsaturated dicarboxylic anhydride monomer units is within this range, the maleimide copolymer exhibits excellent thermal stability. The content of unsaturated dicarboxylic anhydride monomer units is a value determined by titration.

[0030] In one embodiment of the present invention, the maleimide copolymer (A) preferably contains 30-70% by mass of maleimide monomer units, 20-60% by mass of styrene monomer units, 0-20% by mass of acrylonitrile monomer units, and 0-10% by mass of unsaturated dicarboxylic anhydride monomer units per 100% by mass. More preferably, the maleimide copolymer (A) contains 35-60% by mass of maleimide monomer units, 35-55% by mass of styrene monomer units, 0-15% by mass of acrylonitrile monomer units, and 0-5% by mass of unsaturated dicarboxylic anhydride monomer units per 100% by mass. If the constituent units are within the above ranges, the maleimide copolymer (A) exhibits excellent flowability, heat resistance, and thermal stability.

[0031] From the perspective of effectively improving the heat resistance of the resin composition, the glass transition temperature (Tmg) of the maleimide copolymer (A) is preferably 175°C to 205°C. The glass transition temperature is a measured value obtained by DSC under the following conditions.

[0032] Device name: Robot DSC6200 manufactured by Seiko Instruments Co., Ltd.

[0033] Heating rate: 10℃ / minute

[0034] The weight-average molecular weight (Mw) of the maleimide copolymer (A) is preferably 60,000 to 150,000, more preferably 70,000 to 140,000. Specifically, it is, for example, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, or 150,000, or any two of the listed values. If the weight-average molecular weight (Mw) of the maleimide copolymer (A) is within the above range, the resin composition exhibits excellent impact strength. In order to control the weight-average molecular weight (Mw) of the maleimide copolymer (A), in addition to adjusting the polymerization temperature, polymerization time, and polymerization initiator addition amount, methods such as adjusting the solvent concentration and chain transfer agent addition amount can also be used. The weight-average molecular weight of the maleimide copolymer (A) is a polystyrene equivalent value measured by gel permeation chromatography (GPC) under the following conditions.

[0035] Device Name: SYSTEM-21Shodex (manufactured by Showa Denko Corporation)

[0036] Column: PL gel MIXED-B 3 in series

[0037] Temperature: 40℃

[0038] Detection: Differential Refractive Index

[0039] Solvent: Tetrahydrofuran

[0040] Concentration: 2% by mass

[0041] Standard curve: plotted using standard polystyrene (PS) (manufactured by PL Corporation).

[0042] As a method for manufacturing maleimide copolymers (A), known methods can be employed. For example, there are methods such as copolymerizing a monomer mixture consisting of styrene monomers, maleimide monomers, unsaturated dicarboxylic anhydride monomers, and other copolymerizable monomers; or copolymerizing a monomer mixture consisting of styrene monomers, unsaturated dicarboxylic anhydride monomers, and other copolymerizable monomers, and then reacting a portion of the unsaturated dicarboxylic anhydride monomer units with ammonia or a primary amine to imidize them into maleimide monomer units (hereinafter referred to as the "post-imidization method").

[0043] The polymerization methods for maleimide copolymers (A) include solution polymerization and bulk polymerization. From the viewpoint that a more homogeneous polymer composition can be obtained by adding the copolymer batches while polymerization, solution polymerization is preferred. The solvent for solution polymerization is preferably non-polymerizable from the viewpoint that it is less likely to generate byproducts and has minimal adverse effects. Examples include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetophenone; ethers such as tetrahydrofuran and 1,4-dioxane; aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; and N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. From the viewpoint that the solvent can be easily removed during devolatilization recovery of the maleimide copolymer (A), methyl ethyl ketone and methyl isobutyl ketone are preferred. For the polymerization process, continuous polymerization, batch polymerization, and semi-batch polymerization are all applicable. The polymerization method is not particularly limited, but from the viewpoint that it can be manufactured with good productivity through a simple process, free radical polymerization is preferred.

[0044] Polymerization initiators and chain transfer agents can be used in solution polymerization or bulk polymerization. The polymerization temperature is preferably in the range of 80–150 °C. Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, azodicyclohexylformitrile, azodimethylpropionitrile, and azodimethylbutyronitrile; and peroxides such as benzoyl peroxide, tert-butyl peroxide, 1,1-di(tert-butylperoxy)cyclohexane, tert-butylperoxyisopropyl monocarbonate, tert-butyl peroxide-2-ethylhexanoate, di-tert-butyl peroxide, dicumyl peroxide, and ethyl-3,3-di(tert-butylperoxy)butyrate. One or more of these initiators can be used. From the viewpoint of controlling the polymerization rate and polymerization yield, azo compounds or organic peroxides with a 10-hour half-life of 70–120 °C are preferred. The amount of polymerization initiator used is not particularly limited, but it is preferably 0.1 to 1.5% by mass relative to 100% by mass of all monomer units, and more preferably 0.1 to 1.0% by mass. If the amount of polymerization initiator used is 0.1% by mass or more, a sufficient polymerization rate can be obtained, which is therefore preferred. If the amount of polymerization initiator used is 1.5% by mass or less, the polymerization rate can be suppressed, thus the reaction is easily controlled and the target molecular weight is easily obtained. Examples of chain transfer agents include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptosulfonate, limonene, and terpinene. The amount of chain transfer agent used is not particularly limited as long as the target molecular weight can be obtained, but it is preferably 0.1 to 0.8% by mass relative to 100% by mass of all monomer units, and more preferably 0.15 to 0.5% by mass. If the amount of chain transfer agent used is 0.1% to 0.8% by mass, the target molecular weight can be easily obtained.

[0045] The introduction of maleimide monomer units into the maleimide copolymer (A) can be achieved through methods of copolymerizing maleimide monomers and post-imidization. Post-imidization is preferred because it results in a lower amount of residual maleimide monomers in the maleimide copolymer (A). Post-imidization involves copolymerizing a mixture of styrene monomers, unsaturated dicarboxylic anhydride monomers, and other copolymerizable monomers, followed by imidization of a portion of the unsaturated dicarboxylic anhydride monomer units with ammonia or a primary amine to convert them into maleimide monomer units. Examples of primary amines include alkylamines such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, and decylamine, as well as chlorinated or bromine-substituted alkylamines; and aromatic amines such as aniline, toluidine, and naphthylamine, with aniline being preferred. These primary amines can be used alone or in combination of two or more. When post-imidization is employed, a catalyst can be used to improve the dehydration and ring-closing reaction in the reaction between the primary amine and the unsaturated dicarboxylic anhydride monomer unit. Examples of catalysts include tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, and N,N-diethylaniline. The post-imidization temperature is preferably 100–250°C, more preferably 120–200°C. If the post-imidization reaction temperature is above 100°C, the reaction rate can be increased, which is preferable from a productivity point of view. If the imidization reaction temperature is below 250°C, the decrease in physical properties caused by thermal degradation of the maleimide copolymer (A) can be suppressed, which is also preferable.

[0046] The method for removing volatile components such as solvents and unreacted monomers used in solution polymerization from the solution or solution after imidization of maleimide copolymer (A) (the devolatilization method) can employ known methods. For example, a vacuum devolatilization tank with a heater or a devolatilization extruder with venting holes can be used. The devolatilized molten maleimide copolymer (A) is transferred to the granulation process, extruded in a rope-like manner from a porous die, and processed into granules using cold cutting, air hot cutting, or underwater hot cutting methods.

[0047] When the total amount of maleimide copolymer (A) and resin (B) is taken as 100% by mass, the content of maleimide copolymer (A) in the resin composition is preferably 5-45% by mass, more preferably 7-35% by mass, further preferably 10-30% by mass, and even more preferably 20-30% by mass. Specifically, for example, it is 5, 10, 15, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40 or 45% by mass, or it can be within any range between two of the exemplified values. If the content of maleimide copolymer (A) is too low, the heat resistance of the resin composition will not be sufficiently improved. If it is too high, the fluidity will decrease and the moldability will deteriorate. It should be noted that the resin included in the resin composition may substantially consist only of maleimide copolymer (A) and resin (B).

[0048] The resin (B) can be selected from ABS resin, ASA resin, AES resin, or SAN resin, and one or more types can be used.

[0049] ABS resin, ASA resin, and AES resin are graft copolymers formed by graft copolymerizing a rubber-like polymer with at least styrene-based monomers and acrylonitrile-based monomers. For example, when butadiene-based rubbers such as polybutadiene and styrene-butadiene copolymers are used as the rubber-like polymer, it is ABS resin; when acrylic rubbers such as butyl acrylate or ethyl acrylate are used, it is ASA resin; and ethylene-based rubbers such as ethylene-α-olefin copolymers are used, it is AES resin. Two or more of these rubber-like polymers can be used in combination during graft copolymerization.

[0050] As a method for manufacturing graft copolymers of ABS resins, etc., known methods can be used. For example, manufacturing methods using emulsion polymerization or continuous bulk polymerization can be cited. The method of emulsion polymerization is preferred because it is easy to adjust the content of rubbery polymer in the final resin composition.

[0051] The method for manufacturing graft copolymers using emulsion polymerization involves emulsifying and grafting a rubber-like polymer latex with styrene-based monomers and acrylonitrile-based monomers (hereinafter referred to as "emulsion graft polymerization"). The latex of the graft copolymer can be obtained using emulsion graft polymerization.

[0052] In emulsified graft polymerization, water, emulsifiers, polymerization initiators, and chain transfer agents are used, and the polymerization temperature is preferably in the range of 30–90°C. Emulsifiers include anionic surfactants, cationic surfactants, and amphoteric surfactants. Polymerization initiators include organic peroxides such as cumene hydroperoxide, dicumene peroxide, tert-butyl peroxyacetate, tert-hexyl peroxybenzoate, and tert-butyl peroxybenzoate; persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as azobisisobutyronitrile; reducing agents such as ferric ions; secondary reducing agents such as sodium formaldehyde sulfoxylate; and chelating agents such as disodium ethylenediaminetetraacetate. Chain transfer agents include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptosulfonate, limonene, and terpinene.

[0053] The latex of the graft copolymer can be coagulated and recycled using known methods. For example, a coagulant is added to the latex of the graft copolymer to cause it to coagulate, and then it is washed and dehydrated using a dehydrator, followed by a drying process to obtain a powdered graft copolymer.

[0054] From the viewpoint of impact resistance, the content of the rubbery polymer in the graft copolymer obtained by emulsion graft polymerization is preferably 40-70% by mass, more preferably 45-65% by mass. The content of the rubbery polymer can be adjusted, for example, by adjusting the ratio of styrene monomers and acrylonitrile monomers to the rubbery polymer during emulsion graft polymerization.

[0055] From the viewpoint of impact resistance or chemical resistance, the constituent units other than the rubbery polymer of the graft copolymer obtained by emulsification graft polymerization are preferably 65-85% by mass of styrene monomer units and 15-35% by mass of acrylonitrile monomer units.

[0056] The gel component of the graft copolymer is preferably in particulate form. The gel component is a rubbery polymer particle formed by the graft copolymerization of styrene-based monomers and acrylonitrile-based monomers. It is insoluble in organic solvents such as methyl ethyl ketone (MEK) and toluene, and can be separated by centrifugation. Sometimes, it can form an inclusion structure where styrene-acrylonitrile copolymer is encapsulated within the rubbery polymer particles. If the graft copolymer and styrene-acrylonitrile copolymer are melt-blended, the gel component exists as a dispersed phase in the continuous phase of the styrene-acrylonitrile copolymer in particulate form. The gel component is calculated by dissolving a mass W of the graft copolymer in MEK, centrifuging at 20,000 rpm to precipitate the insoluble matter, decanting to remove the supernatant, and obtaining the insoluble component. The mass S of the dried insoluble component is then calculated using the formula gel component (mass %) = (S / W) × 100. Alternatively, the gel component can be calculated by similarly dissolving a resin composition of a melt-blended graft copolymer and styrene-acrylonitrile copolymer in MEK and centrifuging.

[0057] From the viewpoint of impact resistance and appearance of the molded product, the volume average particle size of the gel component of the graft copolymer is preferably in the range of 0.10 to 1.0 μm, more preferably 0.15 to 0.50 μm. The volume average particle size is calculated as follows: particles of a resin composition are obtained by melt blending the graft copolymer with a styrene-acrylonitrile copolymer; ultrathin sections are cut from these particles; and the particles are observed using a transmission electron microscope (TEM). The calculation is based on the image analysis of the particles dispersed in the continuous phase. The volume average particle size can be adjusted, for example, by adjusting the latex particle size of the rubber-like polymer used in the emulsified graft polymerization. The latex particle size of the rubber-like polymer can be adjusted by adjusting the method of adding the emulsifier or the amount of water used during emulsified polymerization. However, to obtain the preferred range, the polymerization time needs to be extended, which reduces productivity. Therefore, the following method can be used: the rubber-like polymer with a particle size of about 0.1 μm is polymerized for a short time, and then the rubber particles are enlarged using chemical or physical agglomeration methods.

[0058] From the viewpoint of impact resistance, the grafting rate of the graft copolymer is preferably 10–100% by mass, more preferably 20–70% by mass. The grafting rate is calculated from the content of gel component (G) and rubber-like polymer (RC) using the formula: grafting rate (mass%) = [(G-RC) / RC] × 100. The grafting rate represents the amount of styrene-acrylonitrile copolymer bonded by grafting and the amount of styrene-acrylonitrile copolymer encapsulated within the particles per unit mass of rubber-like polymer. The grafting rate can be adjusted, for example, by adjusting the ratio of monomer to rubber-like polymer, the type and amount of initiator, the chain transfer dosage, the emulsification dosage, the polymerization temperature, the feeding method (one-time / multiple / continuous), and the monomer addition rate during emulsion graft polymerization.

[0059] From the perspective of impact resistance and the appearance of the molded product, the toluene swelling ratio of the graft copolymer is preferably 5 to 20 times. Toluene swelling ratio indicates the degree of crosslinking of the rubber-like polymer particles and is calculated as follows: the graft copolymer is dissolved in toluene, the insoluble components are separated by centrifugation or filtration, and the mass of the state after swelling with toluene is calculated as the ratio of the mass of the dried state after vacuum drying to remove toluene. The toluene swelling ratio is affected, for example, by the degree of crosslinking of the rubber-like polymer used in emulsified graft polymerization, and can be adjusted by adding initiators, emulsifiers, adjusting the polymerization temperature, and adding multifunctional monomers such as divinylbenzene during the emulsification polymerization of the rubber-like polymer.

[0060] SAN resin is a copolymer containing styrene-based monomer units and acrylonitrile-based monomer units, such as styrene-acrylonitrile copolymers.

[0061] Other copolymerizable monomers for SAN resins include (meth)acrylate monomers such as methyl methacrylate, acrylate monomers such as butyl acrylate and ethyl acrylate, (meth)acrylate monomers such as methacrylic acid, acrylic acid monomers such as acrylic acid, and N-substituted maleimide monomers such as N-phenylmaleimide.

[0062] The SAN resin preferably comprises 60-90% by mass of styrene monomer units and 10-40% by mass of vinyl cyanide monomer units, more preferably 65-80% by mass of styrene monomer units and 20-35% by mass of vinyl cyanide monomer units. When the constituent units are within the above range, the resulting resin composition exhibits an excellent balance between impact strength and flowability. The contents of styrene monomer units and vinyl cyanide monomer units are values ​​measured using 13C-NMR.

[0063] Known methods can be used to manufacture SAN resin. For example, bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be employed. As for the operation of the reaction apparatus, continuous, batch, and semi-batch methods are all applicable. Considering both quality and productivity, bulk polymerization or solution polymerization is preferred, with continuous polymerization being the most preferred. Solvents used in bulk polymerization or solution polymerization include, for example, alkylbenzenes such as benzene, toluene, ethylbenzene, and xylene; ketones such as acetone and methyl ethyl ketone; and aliphatic hydrocarbons such as hexane and cyclohexane.

[0064] In the bulk or solution polymerization of SAN resin, polymerization initiators and chain transfer agents can be used, and the preferred polymerization temperature is in the range of 120–170°C. Examples of polymerization initiators include peroxyacetals such as 1,1-di(tert-butylperoxide)cyclohexane, 2,2-di(tert-butylperoxide)butane, 2,2-di(4,4-di-tert-butylperoxidecyclohexyl)propane, and 1,1-di(tert-pentylperoxide)cyclohexane; hydroperoxides such as cumene hydroperoxide and tert-butyl hydroperoxide; alkyl peroxides such as tert-butyl acetate peroxide and tert-pentyl benzoate peroxide; and di-tert-butylperoxide, di-tert-butylperoxide, di-tert-butylperoxide, and di-tert-hexylperoxide. Alkyl peroxides, peroxide esters such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, and tert-butyl peroxyisopropyl monocarbonate; peroxy carbonates such as tert-butyl peroxyisopropyl carbonate and polyether tetra(tert-butyl peroxycarbonate); N,N'-azobis(cyclohexane-1-onitrile), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylpentanonitrile), and N,N'-azobis[2-(hydroxymethyl)propionitrile], etc., may be used, either one or a combination of two or more. Chain transfer agents include, for example, n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptoside, limonene, and terpinene.

[0065] Deviation methods for removing unreacted monomers or volatile components such as solvents used in solution polymerization from the solution after SAN resin polymerization can be employed using known methods. For example, a vacuum devolatilization tank with a preheater or a devolatilization extruder with an exhaust port can be used. The devolatilized molten SAN resin can be transferred to a granulation process, where it is extruded in a rope-like manner through a porous die and processed into granules using cold cutting, air hot cutting, or underwater hot cutting methods.

[0066] From the viewpoint of impact resistance and moldability of the resin composition, the weight-average molecular weight of SAN resin is preferably 50,000 to 250,000, more preferably 70,000 to 200,000. Specifically, it can be, for example, 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, or 200,000, or within any range of two of the exemplified values. The weight-average molecular weight of SAN resin is a polystyrene equivalent value obtained by gel permeation chromatography (GPC) in THF solvent, and is obtained by the same method as for maleimide copolymers (A). The weight-average molecular weight can be adjusted by adjusting the type and amount of chain transfer agent, solvent concentration, polymerization temperature, and type and amount of polymerization initiator during polymerization.

[0067] As for resin (B), examples include using powdered ABS resin obtained by emulsification polymerization and granular SAN resin obtained by continuous bulk polymerization. Another example is a method of producing granular ABS resin by melt-mixing powdered ABS resin obtained by emulsification polymerization and granular SAN resin obtained by continuous bulk polymerization using an extruder or similar means.

[0068] The method of melt-blending maleimide copolymer (A) and resin (B) selected from at least one of ABS resin, ASA resin, AES resin, and SAN resin using an extruder can be a known method. Known extruders can be used, such as twin-screw extruders, single-screw extruders, multi-screw extruders, and continuous mixers with twin-screw rotors. A twin-screw extruder is preferred, and a widely used intermeshing co-rotating twin-screw extruder is more preferred.

[0069] In embodiments of the present invention, a biaxial extruder is, for example... Figure 1As shown, the space where the cylinders are configured is divided into multiple zones from the raw material input section to the output section, and the temperature of each zone can be controlled. In this invention, the cylinder temperature of the mixing section refers to the set temperature of the zone where the mixing cylinder (mixing element) has the highest temperature in the area where the materials are being mixed and melted. The cylinder temperature of the mixing section is preferably 220–330°C, more preferably 220–300°C. Specifically, it can be, for example, 220, 230, 240, 250, 270, 280, 290, 300, 310, 320, and 330°C, or any range between the two illustrated values.

[0070] From a production standpoint, it is preferable to use a screw with a large groove ratio in the twin-screw extruder as an embodiment of the present invention. The groove ratio is defined by the ratio D / d of the screw's outer diameter (D) and valley diameter (d). The groove ratio can be uniform throughout the screw or it can vary in each region. In the mixing section of the present invention, the groove ratio refers to the groove ratio of the region where the mixing element has the highest temperature in the region where the material is being mixed and melted. In the embodiments of the present invention, from a production standpoint, the groove ratio in the mixing section of the twin-screw extruder is preferably 1.55 or higher, more preferably 1.55 or higher and 1.70 or lower, and even more preferably 1.55 or higher and 1.65 or lower. Specifically, for example, it is 1.55, 1.56, 1.57, 1.58, 1.59, 1.60, 1.65, or 1.70, or it can be within any range between two of the illustrated values.

[0071] From a production point of view, in the embodiments of the present invention, when the discharge rate of melt mixing is set to Q (kg / h) and the screw outer diameter is set to D (mm), it is preferable that the ratio of Q / D is... 2.5 The extrusion is performed in the range of 0.019 to 0.050, more preferably in the range of 0.022 to 0.030. Specifically, for example, it is 0.019, 0.022, 0.025 or 0.028, or it can be within the range of any two of the exemplified values.

[0072] From a dispersibility perspective, in the embodiments of the present invention, when the screw rotation speed is set to Ns (rpm) during melt mixing, Ns / D -0.5 The value is preferably 2600 to 5000, more preferably 4100 to 5000. Specifically, it can be 2600, 3100, 3600, 4100, 4600 or 5000, or any range between the two exemplified values.

[0073] In embodiments of the present invention, at a shear rate of 120 / sec and the cylinder temperature of the mixing section, the ratio of the melt viscosity of the maleimide copolymer (A) to the melt viscosity of the resin (B) is 1.0 or more and less than 3.4, preferably 1.0 or more and less than 2.2, and more preferably 1.0 or more and less than 1.8. Specifically, for example, it is 1 or more, and 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, or any two of the exemplified values.

[0074] If the melt viscosity ratio is too high, the dispersibility of the maleimide copolymer (A) will be poor.

[0075] Methods for controlling the melt viscosity ratio include adjusting the cylinder temperature of the mixing section, adjusting the content of monomer units constituting the maleimide copolymer (A), and adjusting the content of resin (B). For example, the melt viscosity ratio can be reduced by increasing the cylinder temperature of the mixing section. Furthermore, the melt viscosity ratio can be reduced by decreasing the content of maleimide monomer units constituting the maleimide copolymer (A).

[0076] Melt viscosity was measured using a capillary rheometer with a capillary die of L=40mm and D=1mm, at a shear rate of 120 / sec and at the cylinder temperature in the mixing section of the extruder. The mixing section of the extruder refers to the part of the extruder equipped with screw elements such as highly dispersing kneading discs or dough-kneading discs in a twin-screw extruder.

[0077] Melt blending is preferably carried out in the presence of an antioxidant (C). The antioxidant is preferably a hindered phenolic antioxidant, but phosphorus-based antioxidants may also be used in combination.

[0078] Hindered phenolic antioxidants are antioxidants whose basic skeleton contains phenolic hydroxyl groups. Examples of hindered phenolic antioxidants include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, ethylene bis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis[(n-dodecylthio)methyl]-o-cresol, and 2,4-dimethyl-6-(1-methyldecayl)-[ ... Pentaalkylphenol, tetra[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, 4,4'-thiobis(6-tert-butyl-3-methylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-butylenebis(3-methyl-6-tert-butylphenol), bis-[3,3-bis-(4'-hydroxy-3'-tert-butylphenyl)butyric acid]-ethylene glycol ester, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, etc. Preferably, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, ethylene bis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], or pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. More preferably, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Hindered phenolic antioxidants can be used alone or in combination of two or more.

[0079] Phosphorus-based antioxidants are phosphites of trivalent phosphorus compounds. Examples of phosphorus-based antioxidants include 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butylphenyl[d,f][1,3,2]dioxaphosphatine, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]undecane, bis(2,4-cumylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butyl-1-phenoxy)(2-ethylhexyloxy)phosphite, tri(2,4- Di-tert-butylphenyl) phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl] ethyl phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, cyclooctylpentanetetrayl bis(octadecyl phosphite), bis(nonylphenyl) pentaerythritol diphosphite, 4,4'-biphenylene diphosphate tetra(2,4-di-tert-butylphenyl), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenyl diphosphite, etc. Preferably, it is 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butylphenyl[d,f][1,3,2]dioxopyroxene, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, bis(2,4-cumylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butyl-1-phenoxy)(2-ethylhexyloxy)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite. More preferably, 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butylphenyl[d,f][1,3,2]dioxaphosphatine, bis(2,4-cumylphenyl)pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and even more preferably 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butylphenyl[d,f][1,3,2]dioxaphosphatine, bis(2,4-cumylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite. Phosphorus-based antioxidants can be used alone or in combination of two or more.

[0080] When the cylinder temperature in the mixing section is above 290°C, a free radical scavenger is preferred as an antioxidant (C). Examples of free radical scavengers include 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate and 2,4-di-tert-pentyl-6-[1-(3,5-di-tert-pentyl-2-hydroxyphenyl)ethyl]phenyl acrylate.

[0081] The amount of antioxidant (C) added is preferably 0.1 to 0.5 parts by mass relative to a total of 100 parts by mass of maleimide copolymer (A) and resin (B), more preferably 0.3 to 0.5 parts by mass. Specifically, it is, for example, 0.1, 0.2, 0.3, 0.4 or 0.5 parts by mass, or it can be within any range between two of the exemplified values.

[0082] In the manufacture of the heat-resistant resin composition, other resin components, impact modifiers, flow modifiers, hardness modifiers, antioxidants, inorganic fillers, matting agents, flame retardants, flame retardant additives, anti-drip agents, slip-improving agents, exothermic agents, electromagnetic wave absorbers, plasticizers, lubricants, release agents, ultraviolet absorbers, light stabilizers, antibacterial agents, antifungal agents, antistatic agents, carbon black, titanium dioxide, pigments, dyes, etc., may be contained within a range that does not impair the effects of the present invention.

[0083]

Example

[0084] The following examples illustrate the content in detail, but the present invention is not limited to the following examples.

[0085] <Example of manufacturing maleimide copolymer (A-1)>

[0086] The maleimide copolymer (A-1) was manufactured using the following method.

[0087] To a 120-liter autoclave equipped with a stirrer, 42 parts by mass of styrene, 10 parts by mass of acrylonitrile, 4 parts by mass of maleic anhydride, 0.6 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 27 parts by mass of methyl ethyl ketone (MEK) were added. After purging the gas phase with nitrogen, the mixture was stirred and heated to 92°C for 40 minutes. The temperature was maintained at 92°C for 4.5 hours, and then 21 parts by mass of maleic anhydride and 0.15 parts by mass of tert-butyl peroxide dissolved in 85 parts by mass of MEK, along with 20 parts by mass of styrene, were continuously added. Following the addition of maleic anhydride, 0.02 parts by mass of tert-butyl peroxide dissolved in 9 parts by mass of MEK, along with 3 parts by mass of styrene, were continuously added over 30 minutes. The temperature was then raised to 120°C, and the reaction was allowed to proceed for 30 minutes to complete the polymerization. Subsequently, 23 parts by mass of aniline and 0.4 parts by mass of triethylamine were added to the polymerization solution, and the reaction was carried out at 140°C for 7 hours. The imidized reaction solution after the reaction was completed was fed into a degassing extruder to remove volatile components, yielding granular maleimide copolymer (A-1). (A-1) has 52% by mass of styrene units, 8% by mass of acrylonitrile units, 39% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units, with a weight-average molecular weight (Mw) of 80,000 and a glass transition temperature (Tmg) of 176°C.

[0088] <Example of manufacturing maleimide copolymer (A-2)>

[0089] The maleimide copolymer (A-2) was manufactured using the following method.

[0090] To a 120-liter autoclave equipped with a stirrer, 42 parts by mass of styrene, 10 parts by mass of acrylonitrile, 4 parts by mass of maleic anhydride, 0.03 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 27 parts by mass of methyl ethyl ketone (MEK) were added. After purging the gas phase with nitrogen, the mixture was stirred and heated to 92°C for 40 minutes. The temperature was maintained at 92°C for 4.5 hours, and a solution of 21 parts by mass of maleic anhydride and 0.15 parts by mass of tert-butyl peroxide dissolved in 85 parts by mass of MEK, along with 20 parts by mass of styrene, was continuously added. Following the further addition of maleic anhydride, a solution of 0.02 parts by mass of tert-butyl peroxide dissolved in 9 parts by mass of MEK, along with 3 parts by mass of styrene, was continuously added over 30 minutes. After the addition, the temperature was raised to 120°C, and the reaction was allowed to proceed for 30 minutes to complete the polymerization. Subsequently, 23 parts by mass of aniline and 0.4 parts by mass of triethylamine were added to the polymerization solution, and the reaction was carried out at 140°C for 7 hours. After the reaction, the imidized reaction solution was fed into a degassing extruder to remove volatile components, yielding granular maleimide copolymer (A-2). (A-2) has 52% by mass of styrene units, 8% by mass of acrylonitrile units, 39% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units, with a weight-average molecular weight (Mw) of 140,000 and a glass transition temperature (Tmg) of 177°C.

[0091] <Example of manufacturing maleimide copolymer (A-3)>

[0092] The maleimide copolymer (A-3) was manufactured using the following method.

[0093] 21 parts by mass of styrene, 14 parts by mass of acrylonitrile, 4 parts by mass of maleic anhydride, 0.03 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 28 parts by mass of methyl ethyl ketone were added to a 120-liter autoclave equipped with a stirrer. After purging the gas phase with nitrogen, the mixture was stirred and heated to 92°C for 40 minutes. The temperature was maintained at 92°C for 5 hours, during which a solution of 25 parts by mass of maleic anhydride and 0.18 parts by mass of tert-butyl peroxide-2-ethylhexanoate dissolved in 87 parts by mass of methyl ethyl ketone, along with 35 parts by mass of styrene, was continuously added. After the addition of styrene, the temperature was raised to 120°C, and the reaction was allowed to proceed for 30 minutes to complete the polymerization. Subsequently, 27 parts by mass of aniline and 0.4 parts by mass of triethylamine were added to the polymerization solution, and the reaction was carried out at 140°C for 7 hours. The resulting imidized reaction solution was fed into a degassing extruder to remove volatile components, yielding granular maleimide copolymer (A-3). (A-3) has 47% by mass of styrene units, 10% by mass of acrylonitrile units, 42% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units. Its weight-average molecular weight is 130,000 Mw, and its glass transition temperature Tmg is 184℃.

[0094] <Production Example of Maleimide Copolymer (A-4)>

[0095] The maleimide copolymer (A-4) was produced by the following method.

[0096] 62 parts by mass of styrene, 11 parts by mass of maleic anhydride, 0.2 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 31 parts by mass of methyl ethyl ketone were charged into an autoclave with a volume of about 120 liters equipped with a stirrer. After purging the system with nitrogen, the temperature was raised to 92°C, and a solution prepared by dissolving 28 parts by mass of maleic anhydride and 0.19 parts by mass of tert-butyl peroxy-2-ethylhexanoate in 110 parts by mass of methyl ethyl ketone was continuously added over 7 hours. After the addition, the temperature was raised to 120°C and the reaction was carried out for 30 minutes to complete the polymerization. Thereafter, 35 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the polymerization solution and reacted at 140°C for 7 hours. The imidization reaction solution after completion of the reaction was charged into an exhaust-type extruder to remove volatile components, obtaining the granular maleimide copolymer (A-4). The styrene unit of (A-4) was 48% by mass, the N-phenylmaleimide unit was 51% by mass, the maleic anhydride unit was 1% by mass, the weight-average molecular weight Mw was 130,000, and the glass transition temperature Tmg was 202°C.

[0097] <ABS Resin (B-1)>

[0098] A commercially available ABS resin GR-3500 (manufactured by Denka Company Limited) was used.

[0099] <SAN Resin (B-2)>

[0100] The SAN resin (B-2) was produced by the following method.

[0101] The polymer was manufactured using continuous bulk polymerization. One fully mixed stirred tank was used in the reactor with a capacity of 30 L. A feed solution containing 60% by mass styrene, 22% by mass acrylonitrile, and 18% by mass ethylbenzene was continuously fed into the reactor at a flow rate of 9.5 L / h. Additionally, tert-butyl peroxide isopropyl carbonate as a polymerization initiator and n-dodecyl mercaptan as a chain transfer agent were continuously added to the feed solution, achieving concentrations of 160 ppm and 400 ppm relative to the feed solution, respectively. The reactor temperature was adjusted to 145 °C. The polymer solution was continuously withdrawn from the reactor and fed into a vacuum devolatilization tank equipped with a preheater to separate unreacted styrene, acrylonitrile, and ethylbenzene. The preheater temperature was adjusted to maintain a polymer temperature of 235 °C and a pressure of 0.4 kPa within the devolatilization tank. The polymer was extracted from the vacuum devolatilization tank using gears, extruded in a rope-like manner, cooled with cooling water, and then cut into granular SAN resin (B-2). (B-2) is composed of 73.5% by mass of styrene units and 26.5% by mass of acrylonitrile units. In addition, the weight-average molecular weight is 146,000.

[0102] <Example · Comparative Example>

[0103] A heat-resistant resin composition was manufactured by melt-blending maleimide copolymers, ABS resin, and antioxidants using an extruder according to the formulations and conditions shown in Table 1. The extruder used was a twin-screw extruder (Toshiba Machine Co., Ltd. TEM-26SX) with an L / D ratio of 48, a screw outer diameter of 26.5 mm, and a screw groove ratio of 1.56. Q / D during extrusion... 2.5 The value is 0.025, Ns / D -0.5 The value was 4633. The antioxidants used are as follows. The evaluation results are shown in Table 1.

[0104] (C-1) Pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF Japan Co., Ltd. Irganox 1010)

[0105] (C-2) Tris(2,4-di-tert-butylphenyl)phosphite (manufactured by BASF Japan Co., Ltd. Irganox 168)

[0106] (C-3)2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate (Sumilizer GS, manufactured by Sumitomo Chemical Co., Ltd.)

[0107] (Melt viscosity ratio)

[0108] Using a capillary rheometer 1D manufactured by Toyo Seiki Co., Ltd., the melt viscosity of maleimide copolymers and ABS resin at a shear rate of 120 / sec and cylinder temperature in the mixing section was measured using a capillary mold with L=40mm and D=1mm, and the melt viscosity ratio was calculated.

[0109] (Mel flow rate)

[0110] Melt flow rate was determined at 220°C with a 98N load based on JIS K7210.

[0111] (Vicat softening temperature)

[0112] The Vicat softening point was determined based on JIS K7206 using the 50 method (load 50N, heating rate 50℃ / hour) with a 10mm × 10mm test piece and a thickness of 4mm. It should be noted that the testing equipment used was the HDT & VSPT testing apparatus manufactured by Toyo Seiki Co., Ltd.

[0113] (Charpy impact strength)

[0114] Charpy impact strength was measured based on JIS K7111-1, using a notched test specimen, with the impact direction determined along the edge. It should be noted that the measuring equipment used was a digital impact testing machine manufactured by Toyo Seiki Co., Ltd.

[0115] (Dispersion Level)

[0116] Using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-50EP), a mirror plate measuring 90mm in length, 55mm in width, and 2mm in thickness was molded under molding conditions of 220°C cylinder temperature and 60°C. The dispersion state of the maleimide copolymer was then observed visually. If the dispersion state of the maleimide copolymer was poor, streaks along the resin flow would be observed on the surface of the molded product.

[0117] Dispersion Level 5: The appearance is very clean and without any flaws.

[0118] Dispersion level 4: Fine striations are visible. Dispersion level 3: Fine striations are visible. Dispersion level 2: Strands are present, resulting in a noticeably undesirable appearance.

[0119] Dispersion Level 1: There are obvious stripes that are considered to have a poor overall appearance.

[0120] Table 1

[0121]

[0122] As shown in Table 1, by melt mixing with an appropriate range of melt viscosity ratios, a heat-resistant resin composition with excellent dispersibility of maleimide copolymers can be produced.

[0123] [Industry Applicability]

[0124] According to the manufacturing method of the present invention, a heat-resistant resin composition with high productivity and excellent dispersibility of maleimide copolymers can be obtained, and the molded articles also have excellent appearance.

Claims

1. A method for manufacturing a heat-resistant resin composition, comprising the step of melt-blending a maleimide copolymer (A) and a resin (B) selected from at least one of ABS resin, ASA resin, AES resin, and SAN resin using an extruder. When the total amount of the maleimide copolymer (A) and the resin (B) is taken as 100% by mass, the content of the maleimide copolymer (A) in the heat-resistant resin composition is 20-45% by mass. In the melt-blending process, when the discharge rate in kg / h is set as Q and the screw outer diameter in mm is set as D, the ratio of Q / D... 2.5 The extrusion is performed in the range of 0.019 to 0.050, the shear rate is 120 / sec, and the ratio of the melt viscosity of the maleimide copolymer (A) to the melt viscosity of the resin (B) is 1.0 or more and less than 3.4 at the cylinder temperature of the mixing section of the extruder.

2. A method for manufacturing a heat-resistant resin composition, comprising the step of melt-blending a maleimide copolymer (A) and a resin (B) selected from at least one of ABS resin, ASA resin, AES resin, and SAN resin using an extruder. When the total amount of the maleimide copolymer (A) and the resin (B) is taken as 100% by mass, the content of the maleimide copolymer (A) in the heat-resistant resin composition is 20-45% by mass. In the melt-blending process, when the screw outer diameter (in mm) is set as D and the screw rotation speed (in rpm) is set as Ns, Ns / D -0.5 The ratio of the melt viscosity of the maleimide copolymer (A) to the melt viscosity of the resin (B) is 1.0 or more and less than 3.4, with a shear rate of 120 / sec and a shear rate of 2600 to 5000, and at the cylinder temperature of the mixing section of the extruder.

3. The method for manufacturing the heat-resistant resin composition according to claim 1 or 2, wherein, The melt-blending process is carried out in the presence of an antioxidant (C).

4. The method for manufacturing the heat-resistant resin composition according to claim 1 or 2, wherein, The extruder is a twin-shaft extruder.

5. The method for manufacturing the heat-resistant resin composition according to claim 4, wherein, The screw groove ratio in the mixing section of the twin-screw extruder is 1.55 or higher.

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