Heat-resistant resin composition and its injection molded article

Abstract

An object of the present invention is to provide a heat-resistant resin composition that does not produce drawstrings during hot plate fusion. According to the present invention, there can be provided a heat-resistant resin composition comprising a maleimide copolymer (A); and at least one resin (B) selected from the group consisting of an ABS resin, an ASA resin, an AES resin, and a SAN resin, wherein the ratio G' / G'' of the storage modulus (G') to the loss modulus (G'') of the heat-resistant resin composition at an angular velocity of 0.63 rad / s at 240 °C as measured based on JIS K 7244-10 is 0.30 or more and 1.00 or less.

Description

Technical Field

[0001] The present invention relates to a heat-resistant resin composition that improves drawability during hot plate fusion and an injection molded article thereof.

Background Art

[0002] Acrylonitrile-butadiene-styrene copolymer resin (ABS resin) exhibits excellent mechanical strength, appearance, chemical resistance, moldability, etc., and is widely used in fields such as automobiles, home appliances, OA equipment, residential building materials, and daily necessities. In applications that require heat resistance such as automotive interior materials, an ABS resin containing a maleimide-based copolymer is also used as a heat resistance imparting material (for example, Patent Document 1, Patent Document 2). In addition, in the joining of resins typified by ABS resin, hot plate fusion in which the resin is pressed against a metal plate heated to a high temperature to join the molten resins to each other is inexpensive and commonly used.

[0003]

Prior Art Documents

[0004]

Patent Documents

[0005]

Patent Document 1

[0006]

Patent Document 2

Summary of the Invention

[0007]

Problems to be Solved by the Invention

[0008] However, when the resin melted by the hot plate is pulled away from the hot plate, the resin is stretched to generate draw, which may damage the appearance of the molded product.

[0009] An object of the present invention is to provide a heat-resistant resin composition that does not generate draw during hot plate fusion.

[0010]

Technical Means for Solving the Problems

[0011] The present inventors have earnestly studied and found that by producing a heat-resistant resin composition comprising a maleimide-based copolymer (A) and at least one resin (B) selected from ABS resin, ASA resin, AES resin, and SAN resin, and having a ratio G′ / G″ of storage modulus (G′) to loss modulus (G″) of 0.30 or more and 1.00 or less at an angular velocity of 0.63 rad / s at 240 °C measured based on JIS K 7244-10, a heat-resistant resin composition that does not generate draw during hot plate fusion and an injection molded article thereof can be obtained, thus completing the present invention.

[0012] That is, the present invention is as follows.

[0013] (1) A heat-resistant resin composition comprising a maleimide copolymer (A) and at least one resin (B) selected from the group consisting of an ABS resin, an ASA resin, an AES resin, and a SAN resin, wherein the ratio G' / G'' of the storage modulus (G') to the loss modulus (G'') at an angular velocity of 0.63 rad / s at 240 °C as measured based on JIS K 7244-10 is 0.30 or more and 1.00 or less.

[0014] (2) The heat-resistant resin composition according to (1), which contains 5 to 40% by mass of the maleimide copolymer (A) and 60 to 95% by mass of the resin (B).

[0015] (3) The heat-resistant resin composition according to (1) or (2), wherein the maleimide copolymer (A) is composed of 40 to 60% by mass of an aromatic vinyl monomer unit and 60 to 40% by mass of a maleimide monomer unit.

[0016] (4) The heat-resistant resin composition according to any one of (1) to (3), wherein the melt flow rate at 220 °C under a condition of 10 kg as measured by the method described in JIS K 7210 is 5 to 30 g / 10 minutes.

[0017] (5) The heat-resistant resin composition according to any one of (1) to (4), wherein the Vicat softening temperature as measured by the method described in JIS K 7206 is 105 °C to 130 °C.

[0018] (6) An injection molded article to which the heat-resistant resin composition according to any one of (1) to (5) is applied.

[0019] (7) The injection molded article according to (6), which is used as an interior part or an exterior part of an automobile.

[0020]

Advantages of the Invention

[0021] The heat-resistant resin composition of the present invention has less wire drawing during hot plate fusion and can provide a heat-resistant resin composition with excellent appearance.

Detailed Description of the Embodiment

[0022] <Term Explanation>

[0023] In this specification, a description such as "A to B" means A or more and B or less.

[0024] The embodiments of the present invention will be described in detail below.

[0025] The heat-resistant resin composition of the present invention is obtained by melt-kneading and devolatilizing and extruding a maleimide copolymer (A) and at least one resin (B) selected from SAN resin (styrene-acrylonitrile copolymer resin), ABS resin (acrylonitrile-butadiene-styrene copolymer resin), ASA resin (acrylonitrile-styrene-acrylic rubber copolymer resin), and AES resin (acrylonitrile-ethylene / propylene rubber-styrene copolymer resin) using an extruder.

[0026] The maleimide copolymer (A) is a copolymer composed of aromatic vinyl monomer units and maleimide monomer units. In the present invention, unsaturated dicarboxylic anhydride monomer units and vinyl cyanide monomer units may be further contained as constituent units.

[0027] Examples of the aromatic vinyl monomer units include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, etc. Among them, styrene is preferred. The aromatic vinyl monomer units may be used alone or in combination of two or more.

[0028] Examples of the maleimide monomer units include N-alkyl maleimides such as N-methyl maleimide, N-butyl maleimide, and N-cyclohexyl maleimide; and N-phenyl maleimide, N-chlorophenyl maleimide, N-methylphenyl maleimide, N-methoxyphenyl maleimide, N-tribromophenyl maleimide, etc. Among them, N-phenyl maleimide is preferred. The maleimide monomer units may be used alone or in combination of two or more. The maleimide monomer units may be, for example, a raw material composed of maleimide monomers. Alternatively, it may be obtained by imidating a raw material composed of unsaturated dicarboxylic acid monomer units with ammonia or a primary amine.

[0029] Examples of the unsaturated dicarboxylic anhydride monomer units include maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic anhydride, etc. Among them, maleic anhydride is preferred. The unsaturated dicarboxylic anhydride monomer units may be used alone or in combination of two or more.

[0030] Examples of the vinyl cyanide monomer units include acrylonitrile, methacrylonitrile, ethylacrylonitrile, fumaronitrile, etc. Among them, acrylonitrile is preferred. The acrylonitrile monomer units may be used alone or in combination of two or more.

[0031] The aromatic vinyl monomer unit of the maleimide copolymer (A) is preferably 40 to 60% by mass, and the maleimide monomer unit is preferably 60 to 40% by mass. More preferably, the aromatic vinyl monomer unit is 45 to 55% by mass, and the maleimide monomer unit is 55 to 45% by mass. When the constituent units are within the above ranges, the maleimide copolymer (A) has excellent fluidity, heat resistance, and thermal stability. In addition, when the aromatic vinyl monomer unit and the maleimide monomer unit are within the above ranges, the compatibility with at least one resin (B) selected from ABS resin, ASA resin, AES resin, and SAN resin described later is improved, and the impact strength of the heat-resistant resin composition is excellent. The content ratios of the aromatic vinyl monomer unit and the maleimide monomer unit are values calculated from the results of 13C-NMR measurement.

[0032] From the aspect of effectively improving the heat resistance of the heat-resistant resin composition, the midpoint glass transition temperature (Tmg) of the maleimide copolymer (A) is preferably 175°C to 200°C, more preferably 185°C to 200°C, and further preferably 195°C to 200°C. The midpoint glass transition temperature (Tmg) is a measured value obtained by DSC measurement based on JIS K-7121 under the following measurement conditions.

[0033] Device name: Robot DSC6200 manufactured by Seiko Instruments Inc.

[0034] Heating rate: 10°C / minute

[0035] In order to increase the midpoint glass transition temperature (Tmg) of the maleimide copolymer (A), the content of the maleimide monomer unit can be increased or copolymerized with a monomer having a high midpoint glass transition temperature (Tmg).

[0036] The weight average molecular weight (Mw) of the maleimide copolymer (A) is preferably 80,000 to 160,000, more preferably 80,000 to 120,000. When the weight average molecular weight (Mw) of the maleimide copolymer (A) is within the above range, the impact strength of the heat-resistant resin composition is excellent. 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, there are also methods such as adjusting the solvent concentration and chain transfer agent addition amount. The weight average molecular weight of the maleimide copolymer (A) is a polystyrene conversion value measured by gel permeation chromatography (GPC) and is measured under the following conditions.

[0037] Device name: SYSTEM-21 Shodex (manufactured by Showa Denko KK)

[0038] Column: 3 PL gel MIXED-B columns connected in series

[0039] Temperature: 40 °C

[0040] Detection: Differential refractive index

[0041] Solvent: Tetrahydrofuran

[0042] Concentration: 2 mass %

[0043] Standard curve: Prepared using standard polystyrene (PS) (manufactured by PL Co., Ltd.).

[0044] As a method for producing the maleimide copolymer (A), a known method can be adopted. For example, there is the following method: a method of copolymerizing a monomer mixture composed of an aromatic vinyl monomer, a maleimide monomer, an unsaturated dicarboxylic anhydride monomer, and other copolymerizable monomers. After copolymerizing a monomer mixture composed of an aromatic vinyl monomer, an unsaturated dicarboxylic anhydride monomer, and other copolymerizable monomers, a part of the unsaturated dicarboxylic anhydride monomer unit is reacted with ammonia or a primary amine for imidization to be converted into a maleimide monomer unit (hereinafter referred to as "post-imidization method").

[0045] The polymerization method of the maleimide copolymer (A) is, for example, solution polymerization, bulk polymerization, etc. From the viewpoint of obtaining a maleimide copolymer (A) with a more uniform polymerization composition by polymerizing while adding in batches, solution polymerization is preferred. The solvent for solution polymerization is preferably non-polymerizable from the viewpoints of being less likely to produce by-products and having little adverse effect. For example, 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; N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, etc. From the viewpoint of being easily able to remove the solvent when devolatilizing and recovering the maleimide copolymer (A), methyl ethyl ketone and methyl isobutyl ketone are preferred. For the polymerization process, a continuous polymerization type, a batch type (batchwise), or a semi-batch type can all be applied. The polymerization method is not particularly limited, but from the viewpoint of being able to be manufactured with good productivity through a simple process, radical polymerization is preferred.

[0046] 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 to 150 °C. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, azobiscyclohexylcarbonitrile, azodimethylpropionitrile, and azodimethylbutyronitrile; peroxides such as benzoyl peroxide, tert-butyl perbenzoate, 1,1-bis(tert-butylperoxy)cyclohexane, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, dicumyl peroxide, and ethyl 3,3-bis(tert-butylperoxy)butyrate. One of them can be used or two or more of them can be used in combination. From the viewpoint of controlling the polymerization reaction rate and polymerization rate, an azo compound or an organic peroxide having a 10-hour half-life at 70 to 120 °C is preferably used. The amount of the polymerization initiator used is not particularly limited, and is preferably 0.1 to 1.5% by mass, more preferably 0.1 to 1.0% by mass, based on 100% by mass of all monomer units. If the amount of the polymerization initiator used is 0.1% by mass or more, a sufficient polymerization rate can be obtained, and thus it is preferred. If the amount of the polymerization initiator used is 1.5% by mass or less, the polymerization rate can be suppressed, so that the reaction is easily controlled and the target molecular weight is easily obtained. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptoacetate, limonene, and terpinolene. The amount of the chain transfer agent used is not particularly limited as long as the target molecular weight can be obtained, but is preferably 0.1 to 0.8% by mass, more preferably 0.15 to 0.5% by mass, based on 100% by mass of all monomer units. If the amount of the chain transfer agent used is 0.1% by mass to 0.8% by mass, the target molecular weight can be easily obtained.

[0047] There are a method of copolymerizing maleimide-based monomers and a post-imide formation method for introducing maleimide-based monomer units of the maleimide-based copolymer (A). The post-imide formation method is preferred because the amount of residual maleimide-based monomers in the maleimide-based copolymer (A) is small. The post-imide formation method is a method in which a monomer mixture composed of an aromatic vinyl monomer, an unsaturated dicarboxylic anhydride-based monomer, and other copolymerizable monomers is copolymerized, and then a part of the unsaturated dicarboxylic anhydride-based monomer units is reacted with ammonia or a primary amine to undergo imidization to be converted into maleimide-based monomer units. As the primary amine, for example, there are alkylamines such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, decylamine, and chlorine- or bromine-substituted alkylamines; aromatic amines such as aniline, toluidine, and naphthylamine, and aniline is preferred among them. These primary amines can be used alone or in combination of two or more. When post-imide formation is carried out, in the reaction of the primary amine with the unsaturated dicarboxylic anhydride-based monomer units, a catalyst can be used to improve the dehydration ring-closure reaction. Examples of the catalyst are tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, and N,N-diethylaniline. The temperature of post-imide formation is preferably 100 to 250 °C, more preferably 120 to 200 °C. If the temperature of the post-imide formation reaction is 100 °C or higher, the reaction rate can be increased, which is preferred from the viewpoint of productivity. If the temperature of the imide formation reaction is 250 °C or lower, the deterioration of physical properties due to thermal degradation of the maleimide-based copolymer (A) can be suppressed, which is thus preferred.

[0048] For the method (devolatilization method) of removing volatile components such as the solvent used in solution polymerization and unreacted monomers from the solution after the completion of solution polymerization of the maleimide-based copolymer (A) or the solution after the completion of imidization, a known method can be adopted. For example, a vacuum devolatilization tank with a heater or a devolatilizing extruder with a vent hole can be used. The devolatilized molten maleimide-based copolymer (A) is transferred to the granulation process, extruded in a rope shape from a porous die, and processed into granules by a cold cutting method, an air hot cutting method, or a water hot cutting method.

[0049] The content of the maleimide-based copolymer (A) in the heat-resistant resin composition is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and still more preferably 10 to 30% by mass. Specifically, for example, it is 5, 10, 15, 20, 25, 30, 35, 36, 37, 38, 39, or 40% by mass, and it can also be within the range of any two of the exemplified values. If the content of the maleimide-based copolymer (A) is too small, the heat resistance of the heat-resistant resin composition is not sufficiently improved. If it is too much, the fluidity decreases and the moldability deteriorates.

[0050] The resin (B) is selected from ABS resin, ASA resin, AES resin, and SAN resin, and one or more than two kinds can be used. When using more than two kinds, for example, it is preferable to use ABS resin and SAN resin in combination, ASA resin and SAN resin in combination, or AES resin and SAN resin in combination.

[0051] ABS resin, ASA resin, and AES resin are graft copolymers formed by graft copolymerizing at least a rubber-like polymer with a styrene-based monomer and an acrylonitrile-based monomer. For example, when using a butadiene-based rubber such as polybutadiene or styrene-butadiene copolymer as the rubber-like polymer, it is an ABS resin; when using an acrylic rubber composed of butyl acrylate or ethyl acrylate, etc., it is an ASA resin; when using an ethylene-based rubber such as ethylene-α-olefin copolymer, it is an AES resin. When performing graft copolymerization, two or more of these rubber-like polymers can be used in combination.

[0052] As a method for manufacturing the graft copolymer such as ABS resin, a known method can be adopted. For example, a manufacturing method using emulsion polymerization or continuous bulk polymerization can be cited. The method using emulsion polymerization is preferable because it is easy to adjust the content of the rubber-like polymer in the final ABS resin composition.

[0053] The manufacturing method of the graft copolymer using emulsion polymerization is a method of emulsion graft copolymerizing the latex of the rubber-like polymer with the styrene-based monomer and the acrylonitrile-based monomer (hereinafter referred to as "emulsion graft polymerization method"). By using the emulsion graft polymerization method, a latex of the graft copolymer can be obtained.

[0054] In the emulsion graft polymerization method, water, an emulsifier, a polymerization initiator, and a chain transfer agent are used, and the polymerization temperature is preferably in the range of 30 to 90°C. Examples of the emulsifier include anionic surfactants, nonionic surfactants, amphoteric surfactants, etc. Examples of the polymerization initiator include organic peroxides such as cumene hydroperoxide, dicumyl peroxide, tert-butyl peroxyacetate, tert-hexyl peroxybenzoate, tert-butyl peroxybenzoate; persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as azobisisobutyronitrile; reducing agents such as iron ions; secondary reducing agents such as sodium formaldehyde sulfoxylate; and chelating agents such as disodium ethylenediaminetetraacetate. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptoacetate, limonene, terpinolene, etc.

[0055] The latex of the graft copolymer can be coagulated and the graft copolymer can be recovered by a known method. For example, a coagulant is added to the latex of the graft copolymer to coagulate it, and it is washed and dehydrated using a dehydrator, and a powdery graft copolymer is obtained through a drying process.

[0056] The content of monomers remaining in the powdery graft copolymer obtained by emulsion graft polymerization is preferably less than 15,000 μg / g, more preferably less than 8,000 μg / g. The content of the remaining monomers can be adjusted by polymerization conditions and is a value quantified by gas chromatography.

[0057] From the viewpoint of impact resistance, the content of the rubbery polymer in the graft copolymer obtained by emulsion graft polymerization is preferably 40 to 70% by mass, more preferably 45 to 65% by mass. The content of the rubbery polymer can be adjusted, for example, by adjusting the usage ratio of the styrene-based monomer and the acrylonitrile-based monomer relative to the rubbery polymer during emulsion graft polymerization.

[0058] From the viewpoints of impact resistance or chemical resistance, the constituent units other than the rubbery polymer of the graft copolymer obtained by emulsion graft polymerization are preferably 65 to 85% by mass of styrene-based monomer units and 15 to 35% by mass of acrylonitrile-based monomer units.

[0059] The gel component of the graft copolymer is preferably in the form of particles. The gel component is particles of a rubbery polymer formed by graft copolymerization of a styrene-based monomer and an acrylonitrile-based monomer, which are insoluble in organic solvents such as methyl ethyl ketone and toluene and can be separated by centrifugation. Sometimes, it can form an inclusion structure in which styrene-acrylonitrile copolymer is included in the form of particles inside the particles of the rubbery polymer. When the graft copolymer is melt-blended with a styrene-acrylonitrile copolymer, the gel component exists as a dispersed phase in the form of particles in the continuous phase of the styrene-acrylonitrile copolymer. The gel component is a value calculated by the formula of gel component (mass%) = (S / W) × 100, where S is the mass of the dried insoluble component obtained by dissolving a graft copolymer of mass W in methyl ethyl ketone, centrifuging the insoluble component at 20,000 rpm using a centrifuge, and removing the supernatant by decantation and then drying it under vacuum. In addition, the gel component can be calculated by centrifugation after dissolving the ABS resin composition obtained by melt-mixing the graft copolymer and the styrene-acrylonitrile copolymer in methyl ethyl ketone.

[0060] From the viewpoints of impact resistance and appearance of the molded article, the volume average particle diameter 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 diameter is a value calculated as follows: Particles of an ABS resin composition obtained by melt-blending a graft copolymer and a styrene-acrylonitrile copolymer are cut into ultrathin sections, observed using a transmission electron microscope (TEM), and calculated based on image analysis of the particles dispersed in the continuous phase. The volume average particle diameter can be adjusted, for example, by adjusting the latex particle diameter of the rubber-like polymer used in the emulsion graft polymerization. The latex particle diameter of the rubber-like polymer can be adjusted by adjusting the addition method of the emulsifier or the amount of water used during emulsion polymerization, but in order to obtain a preferred range, the polymerization time needs to be extended and the productivity decreases. Therefore, the following method can be adopted: A rubber-like polymer with a particle diameter of about 0.1 μm is polymerized for a short time, and then the rubber particles are enlarged by a chemical aggregation method or a physical aggregation method.

[0061] From the viewpoint of impact resistance, the grafting rate of the graft copolymer is preferably 10 to 100% by mass, more preferably 20 to 70% by mass. The grafting rate is a value calculated by the grafting rate (% by mass) = [(G - RC) / RC] × 100 using the gel component (G) and the content of the rubber-like polymer (RC). The grafting rate represents the amount of the styrene-acrylonitrile copolymer bonded by grafting and the styrene-acrylonitrile copolymer encapsulated in the particles contained per unit mass of the rubber-like polymer. The grafting rate can be adjusted, for example, by adjusting the ratio of the monomer to the rubber-like polymer, the type and amount of the initiator, the amount of the chain transfer agent, the amount of the emulsifier, the polymerization temperature, the feeding method (one-time / multiple / continuous), and the addition rate of the monomer during the emulsion graft polymerization.

[0062] SAN resin is a copolymer having styrene-based monomer units and acrylonitrile-based monomer units, such as a styrene-acrylonitrile copolymer.

[0063] As other copolymerizable monomers of SAN resin, (meth)acrylate-based monomers such as methyl methacrylate, acrylate-based monomers such as butyl acrylate and ethyl acrylate, (meth)acrylic acid-based monomers such as methacrylic acid, acrylic acid-based monomers such as acrylic acid, and N-substituted maleimide-based monomers such as N-phenylmaleimide can be used.

[0064] The constituent units of the SAN resin are preferably 60 to 90% by mass of styrene-based monomer units and 10 to 40% by mass of vinyl cyanide monomer units, more preferably 65 to 80% by mass of styrene-based monomer units and 20 to 35% by mass of vinyl cyanide monomer units. If the constituent units are within the above range, the balance between the impact strength and the fluidity of the resulting heat-resistant resin composition is excellent. The contents of the styrene-based monomer units and the vinyl cyanide monomer units are values measured by 13C-NMR.

[0065] As a method for manufacturing SAN resin, a well-known method can be adopted. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. can be used for manufacturing. As an operation method of the reaction apparatus, continuous, batch (batch type), and semi-batch type are all applicable. Considering from the aspects of quality and productivity, bulk polymerization or solution polymerization is preferred, and continuous type is preferred. As solvents for bulk polymerization or solution polymerization, for example, there are alkylbenzenes such as benzene, toluene, ethylbenzene, and xylene; ketones such as acetone and methyl ethyl ketone; aliphatic hydrocarbons such as hexane and cyclohexane, etc.

[0066] In the bulk polymerization or solution polymerization of SAN resin, a polymerization initiator and a chain transfer agent can be used, and the polymerization temperature is preferably in the range of 120 to 170 °C. Examples of the polymerization initiator include peroxyacetals such as 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, 1,1-bis(tert-amylperoxy)cyclohexane; hydroperoxides such as cumene hydroperoxide and tert-butyl hydroperoxide; alkyl peroxides such as tert-butyl peroxyacetate and tert-amyl peroxybenzoate; dialkyl peroxides such as cumyl tert-butyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, and di-tert-hexyl peroxide; peroxide esters such as tert-butyl peroxyacetate, tert-butyl peroxybenzoate, and tert-butyl peroxyisopropyl monocarbonate; peroxycarbonates such as tert-butyl peroxyisopropyl carbonate and polyether tetra(tert-butyl peroxycarbonate); N,N'-azobis(cyclohexane-1-carbonitrile), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylvaleronitrile), N,N'-azobis[2-(hydroxymethyl)propionitrile], etc. One of them can be used or two or more of them can be used in combination. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, α-methylstyrene dimer, ethyl mercaptoacetate, limonene, terpinolene, etc.

[0067] As a devolatilization method for removing volatile components such as unreacted monomers or solvents for solution polymerization from the solution after the polymerization of SAN resin is completed, a well-known method can be adopted. 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 the granulation process, extruded in a rope shape through a porous die, and processed into granules by means of cold cutting, air hot cutting, or water hot cutting.

[0068] The total content of monomers and solvents remaining in the SAN resin is preferably less than 2000 μg / g, more preferably less than 1500 μg / g. The content of the remaining monomers and solvents can be adjusted by devolatilization conditions and is a value quantified by gas chromatography.

[0069] From the viewpoints of the impact resistance and moldability of the obtained heat-resistant resin composition, the weight-average molecular weight of the SAN resin is preferably from 50,000 to 250,000, more preferably from 70,000 to 200,000. Specifically, for example, it is 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, and it may also be within the range of any two of the exemplified values. The weight-average molecular weight of the SAN resin is a polystyrene conversion value measured in a THF solvent using gel permeation chromatography (GPC), and is a value measured by the same method as that of the maleimide-based copolymer (A). The weight-average molecular weight can be adjusted by adjusting the type and amount of the chain transfer agent, the solvent concentration, the polymerization temperature, and the type and amount of the polymerization initiator during polymerization.

[0070] As the resin (B), for example, there can be mentioned a method using two resins, namely, a powdery ABS resin obtained by an emulsion polymerization method and a granular SAN resin obtained by a continuous bulk polymerization method. In addition, there can be mentioned a method in which the powdery ABS resin obtained by an emulsion polymerization method and the granular SAN resin obtained by a continuous bulk polymerization are melt-mixed using an extruder or the like and then made into a granular ABS resin.

[0071] The method of melt-kneading and devolatilizing extrusion of the maleimide-based copolymer (A) and at least one resin (B) selected from an ABS resin, an ASA resin, an AES resin, and a SAN resin using an extruder can be a known method. As the extruder, known apparatuses can be used, for example, a twin-screw extruder, a single-screw extruder, a multi-screw extruder, a continuous kneader with a biaxial rotor, etc. An intermeshing co-rotating twin-screw extruder is widely used and can be preferably used. In addition, these extruders can be used in combination of multiple ones.

[0072] The extruder is composed of a kneading section for melt-kneading the maleimide-based copolymer (A) and the resin (B) and at least one devolatilizing section. The maleimide-based copolymer (A) and the resin (B) supplied to the extruder are first melted in the kneading section and kneaded into a composition with a uniform composition. The kneading section can be composed of known mixing elements such as kneading disks. Downstream of the kneading section, an element having a pushing-back action for pushing the molten resin back to the upstream side is used, and from the viewpoint of kneadability, it is preferable to fill the kneading section. Examples of such an element include a reverse lead full screw type, a reverse misaligned kneading type, and a seal ring.

[0073] The heat-resistant resin composition melt-kneaded by the kneading section is transported in a molten state to the devolatilizing section, and the volatile components are removed through a vacuum exhaust port. The heat-resistant resin composition in a molten state after devolatilization is extruded in a rope shape from a porous die, and a granular heat-resistant resin composition is obtained by a cold cutting method, an air hot cutting method, or a water hot cutting method.

[0074] As a devolatilization extrusion method, the water injection devolatilization method of adding water before the devolatilization section is preferred because of its excellent devolatilization efficiency. For example, after melt-kneading the maleimide copolymer (A) and the resin (B) in the kneading section, a kneading section is further provided to uniformly knead and disperse water in the molten resin, and the upstream devolatilization section volatilizes water and the devolatilizable components simultaneously. The kneading section for adding water and kneading is also preferably in a full state. The addition amount of water is preferably 0.05 to 2.0 parts by mass relative to 100 parts by mass of the total amount of the maleimide copolymer (A) and the resin (B). In addition, the water content of the maleimide copolymer (A) and the resin (B) also effectively contributes to the improvement of the devolatilization efficiency, but too much will cause problems in the operation of the extruder.

[0075] The barrel temperature of the kneading section and the devolatilization section of the extruder is preferably set at 240 °C or higher, more preferably 260 °C or higher, and further preferably 280 °C or higher. By setting the barrel temperature high, the devolatilization efficiency is improved. In particular, the heat-resistant resin composition using the maleimide copolymer has excellent thermal stability, so the devolatilizable components can be reduced by increasing the barrel temperature. On the contrary, the heat-resistant resin composition using the α-methylstyrene copolymer has poor thermal stability, so the content of α-methylstyrene generated by thermal decomposition can be increased by increasing the barrel temperature. The pressure in the devolatilization section is preferably set at 10 mmHg or less when no water is added, and preferably 40 mmHg or less when water is added.

[0076] The content of the devolatilizable components calculated from the formulation of the maleimide copolymer (A) and the resin (B) supplied to the extruder is preferably less than 3,000 μg / g. If the content of the devolatilizable components before extrusion is too much, it becomes difficult to reduce the content of the devolatilizable components in the heat-resistant resin composition.

[0077] The content of the rubber-like polymer in the heat-resistant resin composition is preferably 10 to 20% by mass. If it is too little, the impact resistance decreases, and if it is too much, the stiffness and the deflection temperature under load decrease.

[0078] The acrylonitrile-based monomer unit in the continuous phase separating the gel component from the heat-resistant resin composition is preferably 15 to 35% by mass, more preferably 20 to 30% by mass. If it is too little, the impact resistance decreases, and if it is too much, the fluidity decreases. The heat-resistant resin composition is dissolved in methyl ethyl ketone, and the gel component is separated as an insoluble component by centrifugation. The supernatant obtained by decantation can be used to precipitate the components of the continuous phase with methanol.

[0079] The ratio G′ / G″ of the storage modulus (G′) to the loss modulus (G″) at an angular velocity of 0.63 rad / s at 240 °C as measured by JIS K 7244-10 of the heat-resistant resin composition is 0.30 or more and 1.00 or less.

[0080] Here, if the ratio G′ / G″ of the storage modulus (G′) to the loss modulus (G″) is less than 0.30, the drawability of the heat-resistant resin composition is poor. Additionally, if it is greater than 1.00, the chemical resistance of the heat-resistant resin composition is poor. The ratio G′ / G″ is preferably 0.40 or more and 1.00 or less, more preferably 0.60 or more and 1.00 or less. Specifically, for example, it can be 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, or 1.00, and it can also be within the range of any two of the exemplified values.

[0081] The following methods can be cited to adjust the value of the ratio G′ / G″.

[0082] For example, the value of the ratio G′ / G″ can be increased by adding a rubber component as an additive. From the perspective of the effect of increasing the value of the ratio G′ / G″, a non-crosslinkable rubber component is preferred. More specifically, a polypropylene-based polymer or a polybutadiene-based polymer, etc. are preferred. One type or two or more types of such additives can be used.

[0083] In addition, the value of the ratio G′ / G″ can be increased by polymerizing the AS resin and maleimide-based copolymer in the formulation or by increasing the amount of the ABS resin in the formulation.

[0084] It should be noted that these methods can be used in combination.

[0085] The melt flow rate (under the conditions of 220 °C and 10 kg) of the heat-resistant resin composition measured by the method described in JIS K 7210 is preferably 5 to 30 g / 10 minutes, more preferably 15 to 20 g / 10 minutes. Specifically, for example, it can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, or 30, and it can also be within the range of any two of the exemplified values. If the melt flow rate is too low, the chemical resistance and moldability will decrease, and if it is too high, the drawability will deteriorate.

[0086] The methods for increasing the melt flow rate of the heat-resistant resin composition include adding a fluidity modifier such as silicone oil and reducing the molecular weight of the AS resin and maleimide-based copolymer in the formulation. In addition, the methods for reducing the melt flow rate include increasing the amount of the ABS resin in the formulation and increasing the molecular weight of the AS resin and maleimide-based copolymer in the formulation. Two or more of these methods can be used in combination.

[0087] The Vicat softening temperature of the heat-resistant resin composition is a value measured based on JIS K7206 by the 50 method (load 50 N, heating rate 50 °C / hour), preferably 105 °C to 130 °C, more preferably 110 °C to 120 °C. Specifically, for example, it is 105, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, or 130, and it can also be within the range of any two of the exemplified values. If the Vicat softening temperature is less than 105 °C, the heat resistance of the heat-resistant resin composition is poor. In addition, if it is greater than 130 °C, the moldability and chemical resistance of the heat-resistant resin composition are poor.

[0088] In order to adjust the Vicat softening temperature of the heat-resistant resin composition, the type and amount of the maleimide-based copolymer in the heat-resistant resin composition can be adjusted. For example, methods to increase this value include increasing the blending amount of the maleimide-based copolymer and increasing the maleimide-based monomer units in the maleimide-based copolymer.

[0089] The heat-resistant resin composition may contain other resin components, impact modifiers, fluidity modifiers, hardness modifiers, antioxidants, inorganic fillers, matting agents, flame retardants, flame retardant aids, anti-dripping agents, sliding property imparting agents, heat release agents, electromagnetic wave absorbers, plasticizers, lubricants, mold release agents, ultraviolet absorbers, light stabilizers, antibacterial agents, antifungal agents, antistatic agents, carbon black, titanium oxide, pigments, dyes, etc. within the range that does not impair the effects of the present invention.

[0090] In addition, from the viewpoint of adjusting the value of G′ / G″, the heat-resistant composition may include non-crosslinkable rubber components such as poly(meth)acrylic polymers, polybutadiene polymers, and polyolefin polymers.

[0091] Examples of the non-crosslinkable rubber components include poly(meth)acrylic polymers such as butyl polyacrylate, polyethyl(meth)acrylate, polypropyl(meth)acrylate, polyoctyl(meth)acrylate, poly(2-ethyl)hexyl(meth)acrylate, polybutadiene polymers such as polybutadiene, and polyolefin polymers such as polyethylene and polypropylene. Poly(meth)acrylic polymers and polybutadiene polymers are preferred. These can be used alone or in combination of two or more. In addition, these can be homopolymers or copolymers with monomers copolymerizable therewith.

[0092] The molding method of the heat-resistant resin composition can use a known method. For example, injection molding, sheet extrusion molding, vacuum molding, blow molding, foam molding, profile extrusion molding, etc. can be cited. When molding, the heat-resistant resin composition is usually heated to 200 to 280 °C and then processed, among which, 210 to 270 °C is preferred. The molded product can be used in automobiles, household appliances, OA equipment, building materials for houses, daily necessities, etc. The heat-resistant resin composition of the present invention has excellent thermal stability, and even when molding at a high temperature, the content of the volatile component will not change much. On the contrary, in the heat-resistant resin composition using an α-methylstyrene copolymer, due to the thermal decomposition of the α-methylstyrene copolymer, α-methylstyrene is contained in the molded body according to the resin temperature and residence time in the molding machine.

[0093]

Examples

[0094] The following uses examples to illustrate the details, but the present invention is not limited to the following examples.

[0095] <Manufacturing Example of Maleimide Copolymer (A-1)>

[0096] Into an autoclave with a volume of about 120 liters equipped with a stirrer, 20 parts by mass of styrene, 5 parts by mass of maleic anhydride, 0.1 part by mass of tert-butyl peroxy-2-ethylhexanoate, 0.25 part by mass of α-methylstyrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After replacing the gas phase part with nitrogen, the temperature was raised to 92 °C over 40 minutes while stirring. After the temperature rise, 92 °C was maintained, 28 parts by mass of styrene, 30 parts by mass of maleic anhydride, and 0.22 part by mass of tert-butyl peroxy-2-ethylhexanoate were dissolved in 75 parts by mass of methyl ethyl ketone, and the resulting solution was continuously added over 7 hours. After further adding maleic anhydride, 17 parts by mass of styrene was continuously added over 2 hours. After adding styrene, the temperature was raised to 120 °C and the reaction was allowed to proceed for 1 hour to complete the polymerization. Thereafter, 21.2 parts by mass of aniline and 0.3 part by mass of triethylamine were added to the polymerization solution and reacted at 140 °C for 7 hours. The imidization reaction solution after the reaction was put into an exhaust-type screw extruder to remove volatile components, and a granular maleimide copolymer A-1 was obtained. The constituent units are 51% by mass of styrene units, 48% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units. The midpoint glass transition temperature (Tmg) measured by DSC is 186 °C. In addition, the weight-average molecular weight is 90,000.

[0097] <Manufacturing Example of Maleimide Copolymer (A-2)>

[0098] Into an autoclave with a volume of about 120 liters equipped with a stirrer, 20 parts by mass of styrene, 5 parts by mass of maleic anhydride, 0.1 part by mass of tert-butyl peroxy-2-ethylhexanoate, 0.13 part by mass of α-methylstyrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After purging the gas phase with nitrogen, the temperature was raised to 92 °C over 40 minutes while stirring. After the temperature rise, 92 °C was maintained, and 28 parts by mass of styrene, 35 parts by mass of maleic anhydride, and 0.22 part by mass of tert-butyl peroxy-2-ethylhexanoate were dissolved in 75 parts by mass of methyl ethyl ketone, and the resulting solution was continuously added over 7 hours. After further adding maleic anhydride, 12 parts by mass of styrene was continuously added over 2 hours. After adding styrene, the temperature was raised to 120 °C, and the polymerization was terminated by reacting for 1 hour. Thereafter, 23.1 parts by mass of aniline and 0.3 part by mass of triethylamine were added to the polymerization solution and reacted at 140 °C for 7 hours. The imidization reaction solution after the reaction was put into an exhaust-type screw extruder to remove volatile components, and a granular maleimide-based copolymer A-2 was obtained. The constituent units were 47% by mass of styrene units, 52% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units. The midpoint glass transition temperature (Tmg) measured by DSC was 195 °C. In addition, the weight-average molecular weight was 130,000.

[0099] <Production Example of Maleimide-based Copolymer (A-3)>

[0100] Into an autoclave with a volume of about 120 liters equipped with a stirrer, 20 parts by mass of styrene, 10 parts by mass of acrylonitrile, 5 parts by mass of maleic anhydride, 0.1 part by mass of tert-butyl peroxy-2-ethylhexanoate, 0.10 part by mass of α-methylstyrene dimer, and 12 parts by mass of methyl ethyl ketone were charged. After purging the gas phase with nitrogen, the temperature was raised to 92 °C over 40 minutes while stirring. After the temperature rise, 92 °C was maintained, and 28 parts by mass of styrene, 34 parts by mass of maleic anhydride, and 0.22 part by mass of tert-butyl peroxy-2-ethylhexanoate were dissolved in 75 parts by mass of methyl ethyl ketone, and the resulting solution was continuously added over 7 hours. After further adding maleic anhydride, 13 parts by mass of styrene was continuously added over 2 hours. After adding styrene, the temperature was raised to 120 °C, and the polymerization was terminated by reacting for 1 hour. Thereafter, 20.7 parts by mass of aniline and 0.3 part by mass of triethylamine were added to the polymerization solution and reacted at 140 °C for 7 hours. The imidization reaction solution after the reaction was put into an exhaust-type screw extruder to remove volatile components, and a granular maleimide-based copolymer A-3 was obtained. The constituent units were 48% by mass of styrene units, 46% by mass of N-phenylmaleimide units, and 6% by mass of maleic anhydride units. The midpoint glass transition temperature (Tmg) measured by DSC was 195 °C. In addition, the weight-average molecular weight was 140,000.

[0101] <Production Example of ABS Resin (ABS-1)>

[0102] The ABS resin is manufactured by emulsion graft polymerization. 97 parts by mass of polybutadiene latex (solid component concentration 50%, average particle diameter 0.3 μm), 12 parts by mass of styrene-butadiene latex with a styrene content of 24% (solid component concentration 70%, average particle diameter 0.5 μm), 1 part by mass of sodium stearate, 0.2 part by mass of sodium formaldehyde sulfoxylate, 0.01 part by mass of tetrasodium ethylenediaminetetraacetate, 0.005 part by mass of ferrous sulfate, and 200 parts by mass of pure water are put into a reaction tank equipped with a stirrer, and the temperature is heated to 50°C. 43 parts by mass of a monomer mixture of 75% styrene and 25% acrylonitrile, 0.2 part by mass of tert-dodecyl mercaptan, and 0.06 part by mass of tert-butyl peroxyacetate are continuously added in batches thereto over 5 hours. After the addition is completed, 0.04 part by mass of dicumyl peroxide is added, and the polymerization is further terminated at 70°C over 2 hours to obtain a latex of ABS resin. After adding 0.3 part by mass of Irganox 1076 (manufactured by BASF Japan Co., Ltd.) to the obtained latex, it is coagulated using magnesium sulfate and sulfuric acid to make the pH of the slurry during coagulation 6.8, washed, dehydrated, and then dried to obtain a powdery graft ABS resin. According to the mixing ratio of the raw materials, the content of the rubber-like polymer is 57% by mass. The constituent units other than the rubber-like polymer are measured by NMR to be 75% styrene units and 25% acrylonitrile units. The ABS resin is observed to be dispersed in a particle form by transmission electron microscopy, and the volume average particle diameter is 0.4 μm. The content of the volatile components in the ABS resin is 6,000 μg / g of styrene and less than the detection limit (30 μg / g) of acrylonitrile.

[0103] <Manufacturing Example of SAN Resin (SAN-1)>

[0104] The SAN resin is manufactured by continuous bulk polymerization. One completely mixed tank-type stirred tank is used as the reactor, and polymerization is carried out with a capacity of 20 L. A raw material solution containing 60% by mass of styrene, 22% by mass of acrylonitrile, and 18% by mass of ethylbenzene is prepared and continuously supplied to the reactor at a flow rate of 6.5 L / h. In addition, t-butyl peroxyisopropyl monocarbonate as a polymerization initiator and n-dodecyl mercaptan as a chain transfer agent are continuously added to the supply line of the raw material solution so that their concentrations relative to the raw material solution are 160 ppm and 400 ppm, respectively. The reaction temperature of the reactor is adjusted to 145°C. The polymer solution is continuously withdrawn from the reactor and supplied to a vacuum devolatilization tank with a preheater to separate unreacted styrene, acrylonitrile, and ethylbenzene. The temperature of the preheater is adjusted so that the temperature of the polymer in the devolatilization tank becomes 225°C, and the pressure in the devolatilization tank is 0.4 kPa. The polymer is extracted from the vacuum devolatilization tank using a gear, extruded in a rope shape, cooled with cooling water, and cut to obtain granular SAN resin. The constituent units are 74% by mass of styrene units and 26% by mass of acrylonitrile units. In addition, the weight average molecular weight is 100,000.

[0105] <Manufacturing Example of SAN Resin (SAN-2)>

[0106] The SAN resin is manufactured by continuous bulk polymerization. One completely mixed tank-type stirred tank is used as the reactor, and polymerization is carried out with a capacity of 20 L. A raw material solution containing 57% by mass of styrene, 25% by mass of acrylonitrile, and 18% by mass of ethylbenzene is prepared and continuously supplied to the reactor at a flow rate of 6.5 L / h. In addition, t-butyl peroxyisopropyl monocarbonate as a polymerization initiator and n-dodecyl mercaptan as a chain transfer agent are continuously added to the supply line of the raw material solution so that their concentrations relative to the raw material solution are 160 ppm and 400 ppm, respectively. The reaction temperature of the reactor is adjusted to 145°C. The polymer solution is continuously withdrawn from the reactor and supplied to a vacuum devolatilization tank with a preheater to separate unreacted styrene, acrylonitrile, and ethylbenzene. The temperature of the preheater is adjusted so that the temperature of the polymer in the devolatilization tank becomes 225°C, and the pressure in the devolatilization tank is 0.4 kPa. The polymer is extracted from the vacuum devolatilization tank using a gear, extruded in a rope shape, cooled with cooling water, and cut to obtain granular SAN resin. The constituent units are 70% by mass of styrene units and 30% by mass of acrylonitrile units. In addition, the weight average molecular weight is 120,000.

[0107] <Manufacturing Example of SAN Resin (SAN-3)>

[0108] The SAN resin is manufactured by continuous bulk polymerization. One completely mixed tank-type stirring tank with a capacity of 20 L is used as the reactor for polymerization. A raw material solution containing 60% by mass of styrene, 22% by mass of acrylonitrile, and 18% by mass of ethylbenzene is prepared and continuously supplied to the reactor at a flow rate of 6.5 L / h. In addition, tert-butyl peroxyisopropyl monocarbonate as a polymerization initiator is continuously added to the supply line of the raw material solution so that its concentration relative to the raw material solution becomes 160 ppm. The reaction temperature of the reactor is adjusted to 145 °C. The polymer solution is continuously withdrawn from the reactor and supplied to a vacuum devolatilization tank with a preheater to separate unreacted styrene, acrylonitrile, and ethylbenzene. The temperature of the preheater is adjusted so that the temperature of the polymer in the devolatilization tank becomes 225 °C, and the pressure in the devolatilization tank is 0.4 kPa. The polymer is extracted from the vacuum devolatilization tank by a gear, extruded in a rope shape, cooled with cooling water, and cut to obtain granular SAN resin. The constituent units are 70% by mass of styrene units and 30% by mass of acrylonitrile units. In addition, the weight-average molecular weight is 145,000.

[0109] <Additive-1>

[0110] HP4051 manufactured by Mitsui Dow Chemical Co., Ltd. was used as Additive-1.

[0111] <Additive-2>

[0112] L-1000 manufactured by Mitsubishi Chemical Corporation was used as Additive-2.

[0113] <Additive-3>

[0114] SH-200 10CS manufactured by Showa Kasei Kogyo Co., Ltd. was used as Additive-3.

[0115] <Additive-4>

[0116] PEG-20000 manufactured by Sanyo Chemical Industries, Ltd. was used as Additive-4.

[0117] <Examples and Comparative Examples>

[0118] A heat-resistant resin composition was obtained by melt-kneading and devolatilizing and extruding a maleimide copolymer, an ABS resin, and a SAN resin according to the formulation shown in Table 1 using an extruder. A twin-screw extruder (TEM-35B manufactured by Toshiba Machine Co., Ltd.) was used as the extruder. As the configuration of the extruder, first, a kneading section for melt-kneading each resin was provided, followed by a kneading section for adding water and kneading, and then a devolatilization section. The barrel temperatures of the kneading section and the devolatilization section were set to the set temperatures shown in Table 1, and extrusion was carried out at a screw speed of 250 rpm and a feed rate of 30 kg / hr. Water was added to 0.5% by mass relative to the feed rate, and the pressure in the devolatilization section was 10 mmHg. The following evaluations were performed on the obtained heat-resistant resin composition. The evaluation results are shown in Tables 1 and 2.

[0119] (G′ / G″)

[0120] The measurement of G′ / G″ was carried out using a viscoelasticity measurement device DHR manufactured by TA Instruments Co., Ltd. The measurement was performed using a 25 mm parallel plate at a gap of 0.75 mm, a strain of 5%, and a measurement temperature of 240°C. The values of G′ / G″ at an angular velocity of 0.63 rad / s are shown in Tables 1 and 2.

[0121] (Vicat softening temperature)

[0122] The Vicat softening point was measured based on JIS K7206 using the 50 method (load 50 N, heating rate 50°C / hour) using a test piece of 10 mm × 10 mm and 4 mm thick. It should be noted that a HDT&VSPT test device manufactured by Toyo Seiki Seisaku-sho, Ltd. was used as the measurement equipment.

[0123] (Melt flow rate)

[0124] The melt flow rate was measured based on JIS K7210 at 220°C with a 10 kg load.

[0125] (Charpy impact strength)

[0126] The Charpy impact strength was measured based on JIS K7111-1 using a notched test piece, and the impact direction was along the edge. It should be noted that a digital display impact testing machine manufactured by Toyo Seiki Seisaku-sho, Ltd. was used as the measurement equipment.

[0127] (Drawability)

[0128] The drawability was evaluated based on JIS K-7171 using a test piece of 80 mm × 10 mm × 4 mm. When pressing on a hot plate at 240°C with a 1 kg load for 10 seconds and pulling at a speed of 10 cm / second, the drawability was evaluated in the following 5 stages according to the draw length.

[0129] A: The wire drawing breaks at less than 1.0 cm, B: breaks at 1.0 cm to 4.0 cm, C: breaks at 4.0 cm to 7.0 cm, D: breaks at 7.0 cm to 10.0 cm, E: the wire drawing is 10 cm or more

[0130] (Chemical resistance)

[0131] According to the 1 / 4 ellipse method with the test piece shape of 316×20×2 mm, major radius of 250 mm, and minor radius of 150 mm, the cracks after 48 hours at 23°C were observed. In order to eliminate the influence of molding strain, the molded pellets were pressed at 260°C and the test pieces were manufactured by cutting. Toluene was used as the chemical.

[0132] It should be noted that the critical strain is calculated by the following formula.

[0133] ε = b / 2a 2 {1 - (a 2 - b 2 )X 2 / a 4} 1.5 ×t×100

[0134] Critical strain: ε, major radius: a, minor radius: b, test piece thickness: t, crack occurrence point: X

[0135] The chemical resistance was evaluated from the critical strain according to the following criteria.

[0136] A: 0.8 or more, B: 0.6 to 0.7, C: 0.3 to 0.5, D: 0.2 or less

[0137]

Table 1

[0138]

[0139]

Table 2

[0140]

[0141] From the results of Tables 1 and 2, it can be seen that the wire drawing is improved in the resin with G' / G'' of 0.30 to 1.00, and a heat-resistant resin composition with an excellent balance of heat resistance and appearance can be obtained. The chemical resistance in Examples 1 to 11 is high, and especially the chemical resistance in Examples 5, 9 to 11 is particularly excellent. In addition, when the MFR of the resin is 5 or more, a resin with more excellent chemical resistance can be obtained. Moreover, when using additives, the wire drawing can be improved by increasing G' / G''.

[0142] Although the mechanism of improving drawability by controlling G′ / G″ is not yet clear, it is known that an index related to the dynamic viscoelasticity of the resin composition that becomes in a molten state during hot plate fusion affects drawability. According to the present invention, among the indexes related to dynamic viscoelasticity, controlling G′ / G″ within a specific range makes a great contribution to improving drawability.

[0143]

Industrial Applicability

[0144] By using the heat-resistant resin composition of the present invention, even when joining is performed by hot plate fusion, which is an inexpensive joining technique, there are no appearance defects and molding can be carried out. In addition, even when using a high-flow resin that improves production efficiency, there are no appearance defects during hot plate fusion and molding can be carried out. Furthermore, by controlling G′ / G″ of the resin within the above range, a heat-resistant resin composition having an excellent balance of fluidity, chemical resistance, heat resistance, and appearance can be provided, and it can be suitably used for automobiles, home appliances, OA equipment, housing building materials, daily necessities, etc.

Claims

1. A heat-resistant resin composition comprising a maleimide copolymer (A); at least one resin (B) selected from the group consisting of an ABS resin, an ASA resin, an AES resin, and a SAN resin, and the resin (B) contains at least a SAN resin and an ABS resin; and a non-crosslinkable rubber component, The maleimide copolymer (A) has a weight-average molecular weight of 80,000 to 160,000, The SAN resin has a weight-average molecular weight of 50,000 to 250,000, The ratio G′ / G″ of the storage modulus (G′) to the loss modulus (G″) at an angular velocity of 0.63 rad / s at 240 °C as measured by JIS K 7244-10 of the heat-resistant resin composition is 0.30 or more and 1.00 or less, The maleimide copolymer (A) comprises 40 to 60% by mass of an aromatic vinyl monomer unit and 60 to 40% by mass of a maleimide monomer unit, The heat-resistant resin composition contains 5 to 39% by mass of the maleimide copolymer (A) and 60 to 90% by mass of the resin (B), The constituent units of the SAN resin are 60 to 90% by mass of a styrene monomer unit and 10 to 40% by mass of a vinyl cyanide monomer unit, and the ABS resin is a graft copolymer obtained by graft copolymerizing at least a rubber-like polymer with a styrene monomer and an acrylonitrile monomer, The melt flow rate of the heat-resistant resin composition measured by the method described in JIS K 7210 at 220 °C under a condition of 10 kg is 5 to 30 g / 10 minutes.

2. The heat-resistant resin composition according to claim 1, wherein, The Vicat softening temperature measured by the method described in JIS K 7206 is 105 °C to 130 °C.

3. An injection molded article using the heat-resistant resin composition according to claim 1 or claim 2.

4. The injection molded article according to claim 3, which is used as an interior component or an exterior component of an automobile.

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