WO2022176756A1

WO2022176756A1 - Manufacturing method for heat-resistant resin composition

Info

Publication number: WO2022176756A1
Application number: PCT/JP2022/005269
Authority: WO
Inventors: 広平西野; 正道遠藤
Original assignee: デンカ株式会社
Priority date: 2021-02-17
Filing date: 2022-02-10
Publication date: 2022-08-25
Also published as: JPWO2022176756A1; TW202244172A

Abstract

Provided is a manufacturing method for a heat-resistant resin composition that excels in shock resistance. Provided is a manufacturing method for a heat-resistant resin composition including a step for melt-kneading a maleimide-based copolymer (A) and an ABS-based resin (B) with an extruding machine, said manufacturing method for a heat-resistant resin composition being such that the melt-kneading is carried out in the presence of at least one radical scavenger (C) selected from among 2-t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate and 2, 4-di-t-amyl-6-[1-(3, 5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate.

Description

METHOD FOR MANUFACTURING HEAT-RESISTANT RESIN COMPOSITION

The present invention relates to a method for producing a heat-resistant resin composition with excellent impact resistance.

ABS resin is a thermoplastic resin with acrylonitrile, butadiene, and styrene as main components. widely used for On the other hand, in applications where heat resistance is required, such as automobile interior materials, the heat resistance may be insufficient. Techniques for improving heat resistance include the following, and maleimide-based copolymers and α-methylstyrene-based copolymers are used (Patent Documents 1 to 3). The higher the heat resistance of the maleimide copolymer, the more the heat resistance of the ABS resin can be improved with a small addition amount. requires kneading at high processing temperatures. In addition, by adopting the direct granulation method as a method for producing thermoplastic resins, a drying process that causes oxidative deterioration of the resin becomes unnecessary, and a method of allowing a specific phenolic compound to exist in direct granulation is known. (Patent Document 4).

JP-A-58-183729 JP-A-2003-41080 WO2010/082617 JP-A-5-78430

An object of the present invention is to provide a method for producing a heat-resistant resin composition having excellent impact resistance.

As a result of studies by the present inventors, it was found that when the maleimide-based copolymer and the ABS-based resin are melt-kneaded in an extruder, deterioration of the polybutadiene in the ABS resin is suppressed by performing the melt-kneading in the presence of a radical scavenger. It has been found that a heat-resistant resin composition having excellent impact resistance can be obtained.
That is, the present invention
(1) A method for producing a heat-resistant resin composition comprising a step of melt-kneading a maleimide-based copolymer (A) and an ABS-based resin (B) with an extruder, wherein the melt-kneading is performed by 2-t -butyl-6-(3′-t-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-[1-(3,5-di-t - A method for producing a heat-resistant resin composition, which is carried out in the presence of at least one radical scavenger (C) selected from amyl-2-hydroxyphenyl)ethyl]phenyl acrylate,
(2) The method for producing a heat-resistant resin composition according to (1), wherein the melt-kneading is performed at a cylinder temperature of the kneading section of the extruder at a temperature exceeding 260°C.
(3) The method for producing a heat-resistant resin composition according to (1) or (2), wherein the maleimide copolymer (A) has a glass transition temperature of 175° C. to 210° C.
(4) The content of the radical scavenger (C) is 0.1 to 0.6 parts by mass with respect to a total of 100 parts by mass of the maleimide copolymer (A) and the ABS resin (B), 1) A method for producing a heat-resistant resin composition according to any one of (3),
(5) The method for producing a heat-resistant resin composition according to any one of (1) to (4), wherein the extruder is a twin-screw extruder;
(6) The method for producing a heat-resistant resin composition according to any one of (1) to (5), wherein the heat-resistant resin composition has a Vicat softening temperature of 115° C. or higher.
(7) of (1) to (6), wherein the melt-kneading is performed in the presence of two or more antioxidants (D) selected from hindered phenol-based antioxidants and phosphorus-based antioxidants; A method for producing the heat-resistant resin composition according to any one of
Regarding.

In the method for producing the heat-resistant resin composition of the present invention, the maleimide-based copolymer (A) and the ABS-based resin (B) are melt-kneaded in an extruder in the presence of a radical scavenger. It is possible to obtain a heat-resistant resin composition that suppresses deterioration of polybutadiene in the resin and has excellent impact resistance.

It is the figure which showed the cylinder of a twin-screw extruder typically.

<Description of terms>
In the specification of the present application, for example, the description “A to B” means A or more and B or less.

Hereinafter, embodiments of the present invention will be described in detail. The embodiments shown below can be combined with each other.

<1. Resin composition>
The heat-resistant resin composition of the present invention is a heat-resistant resin composition obtained by melt-kneading a maleimide-based copolymer (A) and an ABS-based resin (B) in an extruder. SAN resin may be included in the process. The Vicat softening temperature of the heat-resistant resin composition is preferably 115°C or higher, more preferably 120°C or higher. The production method of the present invention is more effective when the content of the maleimide-based copolymer with high melt viscosity is high, that is, when the Vicat softening temperature of the heat-resistant resin composition is high, since a higher processing temperature is required. is.

<2. Maleimide-based copolymer (A)>
The maleimide-based copolymer (A) is a copolymer having maleimide-based monomer units and styrene-based monomer units. The present invention can further have acrylonitrile-based monomer units and unsaturated dicarboxylic acid anhydride-based monomer units.

Maleimide-based monomer units include, for example, N-methylmaleimide, N-butylmaleimide, N-alkylmaleimide such as N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, N-tribromophenylmaleimide and the like. Among these, N-phenylmaleimide is preferred. The maleimide-based monomer units may be used alone or in combination of two or more. As for the maleimide-based monomer unit, for example, a raw material comprising a maleimide-based monomer can be used. Alternatively, it can be obtained by imidizing a raw material composed of unsaturated dicarboxylic acid monomer units with ammonia or a primary amine.
The maleimide-based copolymer (A) preferably contains 30 to 70% by mass, more preferably 35 to 60% by mass, of maleimide-based monomer units in 100% by mass of the maleimide-based copolymer (A). more preferred. Specifically, the content of maleimide-based monomer units is, for example, 30, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 50, 55, 60, or 70 mass. % and may be in a range between any two of the numbers exemplified here. If the content of maleimide-based monomer units is within this range, an ABS resin, which is an ABS-based resin (B) described later, is an essential component, and at least one selected from ASA resins, AES resins, and SAN resins. Also, the compatibility with resins in which one type of resin is used in combination is improved, and the impact strength of the resin composition is excellent. The content of maleimide-based monomer units is a value measured by 13C-NMR.

Styrenic monomer units include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α- and methyl-p-methylstyrene. Among these, styrene is preferable from the viewpoints of industrial availability, low cost, copolymerization with various monomers, and light weight and excellent moldability. The styrene-based monomer units may be used alone or in combination of two or more.
The maleimide-based copolymer (A) preferably contains 20 to 60% by mass, more preferably 35 to 55% by mass, of styrene-based monomer units in 100% by mass of the maleimide-based copolymer (A). more preferred. Specifically, for example, 20, 30, 40, 45, 46, 47, 48, 49, 50, 55, or 60% by mass, and within the range between any two of the numerical values exemplified here good too. If the content of the styrene-based monomer unit is within this range, the ABS resin, which is the ABS-based resin (B) described later, is an essential component, and optionally at least one selected from ASA resin, AES resin, and SAN resin. Also, the compatibility with resins in which one type of resin is used in combination is improved, and the impact strength of the resin composition is excellent. The content of styrene-based monomer units is a value measured by 13C-NMR.

Acrylonitrile-based monomer units include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, and the like. Among these, acrylonitrile is preferable from the viewpoint of industrial availability. Acrylonitrile-based monomer units may be used alone, or two or more of them may be used in combination.
The maleimide-based copolymer (A) preferably contains 0 to 20% by mass of acrylonitrile-based monomer units in 100% by mass of the maleimide-based copolymer (A), and may contain 0 to 15% by mass. more preferred. Specifically, for example, it is 0, 5, 6, 7, 8, 9, 10, 15, or 20% by mass, and may be within a range between any two of the numerical values exemplified here. If the content of the acrylonitrile-based monomer unit is within this range, the chemical resistance of the resin composition will be excellent. The content of acrylonitrile-based monomer units is a value measured by 13C-NMR.

The unsaturated dicarboxylic anhydride monomer units include maleic anhydride, itaconic anhydride, citraconic anhydride, and aconitic anhydride. Among these, maleic anhydride is preferable from the viewpoint of industrial availability. The unsaturated dicarboxylic anhydride-based monomer units may be used alone or in combination of two or more.
The maleimide-based copolymer (A) preferably contains 0 to 10% by mass of unsaturated dicarboxylic anhydride-based monomer units in 100% by mass of the maleimide-based copolymer (A), and preferably 0 to 5% by mass. % is more preferable. Specifically, for example, it is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10% by mass, and within the range between any two of the numerical values illustrated here good too. When the content of the unsaturated dicarboxylic acid anhydride-based monomer unit is within this range, the thermal stability of the maleimide-based copolymer is excellent. The content of unsaturated dicarboxylic acid anhydride-based monomer units is a value measured by a titration method.

The maleimide-based copolymer (A) in one aspect of the present invention contains 30 to 70% by mass of maleimide-based monomer units and 20% by mass of styrene-based monomer units in 100% by mass of the maleimide-based copolymer (A). It preferably contains up to 60% by mass, 0 to 20% by mass of acrylonitrile-based monomer units, and 0 to 10% by mass of unsaturated dicarboxylic acid anhydride-based monomer units. More preferably, 35 to 60% by mass of maleimide-based monomer units, 35 to 55% by mass of styrene-based monomer units, and acrylonitrile-based monomer units in 100% by mass of the maleimide-based copolymer (A) 0 to 15% by mass, and 0 to 5% by mass of unsaturated dicarboxylic acid anhydride-based monomer units. If the structural unit is within the above range, the maleimide-based copolymer (A) will be excellent in fluidity, heat resistance, and thermal stability.

From the viewpoint of efficiently improving the heat resistance of the resin composition, the glass transition temperature (midpoint glass transition temperature: Tmg) of the maleimide copolymer (A) is preferably 175°C to 210°C, and more It is preferably 185°C to 205°C. The glass transition temperature is a value measured by DSC under the measurement conditions described below.
Device name: Robot DSC6200 manufactured by Seiko Instruments Inc.
Heating rate: 10°C/min

The weight average molecular weight (Mw) of the maleimide-based copolymer (A) is preferably 60,000 to 150,000, more preferably 70,000 to 140,000. Specifically, it is, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 150,000, and may be within a range between any two of the numerical values exemplified here. If the weight average molecular weight (Mw) of the maleimide-based copolymer (A) is within the above range, the impact strength of the resin composition will be excellent. In order to control the weight average molecular weight (Mw) of the maleimide-based copolymer (A), in addition to adjusting the polymerization temperature, the polymerization time, and the amount of the polymerization initiator added, the solvent concentration and the amount of the chain transfer agent added are adjusted. There are other methods. The weight average molecular weight of the maleimide-based copolymer (A) is a polystyrene-equivalent value measured by gel permeation chromatography (GPC), and was measured under the following conditions.
Device name: SYSTEM-21 Shodex (manufactured by Showa Denko K.K.)
Column: 3 PL gel MIXED-B in series Temperature: 40°C
Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2% by mass
Calibration curve: prepared using standard polystyrene (PS) (manufactured by PL).

A known method can be employed as the method for producing the maleimide-based copolymer (A). For example, there is a method of copolymerizing a monomer mixture comprising styrene-based monomers, maleimide-based monomers, unsaturated dicarboxylic acid anhydride-based monomers, and other copolymerizable monomers. After copolymerizing a monomer mixture consisting of a styrene-based monomer, an unsaturated dicarboxylic anhydride-based monomer, and other copolymerizable monomers, the unsaturated dicarboxylic anhydride-based monomer unit part of is reacted with ammonia or a primary amine to imidize and convert to maleimide-based monomer units (hereinafter referred to as "post-imidation method").

Polymerization modes of the maleimide-based copolymer (A) include, for example, solution polymerization and bulk polymerization. Solution polymerization is preferable from the viewpoint that a maleimide-based copolymer (A) having a more uniform copolymer composition can be obtained by polymerizing while performing partial addition or the like. The solvent for solution polymerization is preferably non-polymerizable from the viewpoint that by-products are less likely to occur and adverse effects are less likely to occur. 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 Examples include sulfoxide and N-methyl-2-pyrrolidone, and methyl ethyl ketone and methyl isobutyl ketone are preferred from the standpoint of ease of solvent removal during devolatilization recovery of the maleimide copolymer (A). Any of a continuous polymerization system, a batch system (batch system), and a semi-batch system can be applied to the polymerization process. The polymerization method is not particularly limited, but radical polymerization is preferable from the viewpoint of being able to produce with high productivity by a simple process.

A polymerization initiator and a chain transfer agent can be used in solution polymerization or bulk polymerization, and the polymerization temperature is preferably in the range of 80 to 150°C. Polymerization initiators include, for example, azo compounds such as azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethylproponitrile, azobismethylbutyronitrile, benzoyl peroxide, t-butyl peroxybenzoate, 1 , 1-di(t-butylperoxy)cyclohexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, di-t-butylperoxide, dicumylperoxide, ethyl- Peroxides such as 3,3-di-(t-butylperoxy)butyrate, which may be used alone or in combination of two or more. From the viewpoint of polymerization reaction rate and polymerization rate control, it is preferable to use an azo compound or an organic peroxide having a 10-hour half-life of 70 to 120°C. The amount of the polymerization initiator used is not particularly limited, but it is preferable to use 0.1 to 1.5% by mass based on 100% by mass of the total monomer units, more preferably 0.1 to It is 1.0% by mass. If the amount of the polymerization initiator used is 0.1% by mass or more, a sufficient polymerization rate can be obtained, which is preferable. When the amount of the polymerization initiator used is 1.5% by mass or less, the polymerization rate can be suppressed, so the reaction control becomes easy, and the target molecular weight can be easily obtained. Chain transfer agents include, for example, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene and the like. The amount of the chain transfer agent used is not particularly limited as long as the target molecular weight is obtained, but it is 0.1 to 0.8% by mass with respect to 100% by mass of the total monomer units. is preferred, and more preferably 0.15 to 0.5% by mass. If the amount of chain transfer agent used is 0.1% by mass to 0.8% by mass, the target molecular weight can be easily obtained.

Introduction of maleimide-based monomer units into the maleimide-based copolymer (A) includes a method of copolymerizing maleimide-based monomers and a post-imidization method. The post-imidation method is preferable because the amount of residual maleimide monomer in the maleimide copolymer (A) is reduced. The post-imidization method involves copolymerizing a monomer mixture consisting of a styrene-based monomer, an unsaturated dicarboxylic anhydride-based monomer, and other copolymerizable monomers, and then adding an unsaturated dicarboxylic acid. In this method, part of the anhydride-based monomer units are reacted with ammonia or a primary amine to imidize them and convert them into maleimide-based monomer units. Primary amines include, for example, alkylamines such as methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine and decylamine. Amines and aromatic amines such as chloro- or bromo-substituted alkylamines, aniline, toluidine, naphthylamine, among which aniline is preferred. These primary amines may be used alone or in combination of two or more. During post-imidization, a catalyst can be used to improve the dehydration ring closure reaction in the reaction between the primary amine and the unsaturated dicarboxylic anhydride monomer units. Catalysts are, for example, tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, N,N-diethylaniline. The temperature for post-imidization is preferably 100 to 250°C, more preferably 120 to 200°C. If the imidization reaction temperature is 100° C. or higher, the reaction rate is improved, which is preferable from the viewpoint of productivity. If the temperature of the imidization reaction is 250° C. or lower, it is possible to suppress deterioration in physical properties due to thermal deterioration of the maleimide copolymer (A), which is preferable.

A method of removing volatiles such as the solvent used in the solution polymerization and unreacted monomers from the solution of the maleimide copolymer (A) after the solution polymerization or the solution after the post-imidation (devolatilization method). can employ a known method. For example, a vacuum devolatilization tank with a heater or a devolatilization extruder with a vent can be used. The devolatilized molten maleimide copolymer (A) is transferred to a granulation process, extruded into strands from a multi-hole die, and pelletized by a cold cut method, an air hot cut method, or an underwater hot cut method. can be processed.

The content of the maleimide copolymer (A) in the resin composition is 5 to 45% by mass when the total amount of the maleimide copolymer (A) and the ABS resin (B) is 100% by mass. is preferably 7 to 35% by mass, more preferably 10 to 30% by mass, still more preferably 20 to 30% by mass. Specifically, for example, 5, 10, 15, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, or 45% by mass, the numerical values illustrated here may be in the range between any two of If the content of the maleimide-based copolymer (A) is too small, the heat resistance of the resin composition may not be sufficiently improved. If the amount is too large, fluidity may decrease and moldability may deteriorate. The resin contained in the resin composition may be substantially only the maleimide copolymer (A) and the ABS resin.

<3. ABS resin (B)>
The ABS-based resin (B) is a resin containing ABS resin as an essential component and optionally at least one resin selected from ASA resin, AES resin and SAN resin. The ABS resin is a graft copolymer obtained by graft-copolymerizing a rubber-like polymer with at least a styrene-based monomer and an acrylonitrile-based monomer. For example, butadiene-based rubbers such as polybutadiene and styrene-butadiene copolymers are used as rubber-like polymers. At the time of graft copolymerization, two or more of these rubber-like polymers may be used in combination. When using an acrylic rubber such as butyl acrylate or ethyl acrylate, an ASA resin may be used, and when using an ethylene rubber such as an ethylene-α-olefin copolymer, an AES resin may be used together.
The content of the ABS resin in the ABS resin (B) is preferably 10 to 100% by mass, more preferably 15 to 60% by mass based on 100% by mass of the ABS resin (B). Specifically, for example, it is 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, or 100% by mass, and within the range between any two of the numerical values illustrated here There may be. The ABS-based resin (B) may be substantially only ABS resin.
Further, the content of the polybutadiene component in the ABS resin (B) is preferably 10 to 35% by mass, more preferably 15 to 30% by mass, based on 100% by mass of the ABS resin (B) from the viewpoint of impact strength. % by mass. Specifically, it is, for example, 10, 15, 20, 25, 30, or 35% by mass, and may be within a range between any two of the numerical values exemplified here.

A known method can be adopted as a method for producing a graft copolymer such as an ABS resin. For example, production methods using emulsion polymerization and continuous bulk polymerization can be mentioned. A method by emulsion polymerization is preferable because it is easy to adjust the content of the rubber-like polymer in the final resin composition.

A method for producing a graft copolymer by emulsion polymerization includes a method in which a styrene-based monomer and an acrylonitrile-based monomer are emulsion-graft-polymerized in a latex of a rubber-like polymer (hereinafter referred to as "emulsion graft polymerization method"). ). A latex of a graft copolymer can be obtained by an emulsion graft polymerization method.

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 emulsifiers include anionic surfactants, onionic surfactants, and amphoteric surfactants. Polymerization initiators include, for example, organic peroxides such as cumene hydroperoxide, diisopropylene peroxide, t-butylperoxyacetate, t-hexylperoxybenzoate, and t-butylperoxybenzoate, potassium persulfate, and ammonium persulfate. azo compounds such as azobisbutyronitrile; reducing agents such as iron ions; secondary reducing agents such as sodium formaldehyde sulfoxylate; and chelating agents such as disodium ethylenediaminetetraacetate. Chain transfer agents include, for example, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene and the like.

The graft copolymer latex can be coagulated by a known method to recover the graft copolymer. For example, a coagulant is added to the latex of the graft copolymer to coagulate it, followed by washing and dehydration with a dehydrator, followed by drying to obtain a powdery graft copolymer.

The content of the rubber-like polymer in the graft copolymer obtained by the emulsion graft polymerization method is preferably 40 to 70% by mass, more preferably 45 to 65% by mass, from the viewpoint of impact resistance. . The content of the rubber-like polymer can be adjusted, for example, by adjusting the ratio of the styrene-based monomer and the acrylonitrile-based monomer to the rubber-like polymer used during emulsion graft polymerization.

From the viewpoint of impact resistance and chemical resistance, the constituent units excluding the rubber-like polymer of the graft copolymer obtained by the emulsion graft polymerization method include 65 to 85% by mass of styrene-based monomer units and acrylonitrile-based monomers. The body unit content is preferably 15 to 35% by mass.

The gel content of the graft copolymer is preferably particulate. The gel content is particles of a rubber-like polymer obtained by graft copolymerization of a styrene-based monomer and an acrylonitrile-based monomer, and is a component that is insoluble in organic solvents such as methyl ethyl ketone and toluene and separated by centrifugation. In some cases, an occlusion structure in which the styrene-acrylonitrile copolymer is encapsulated in the form of particles is formed inside the particles of the rubber-like polymer. When the graft copolymer and the styrene-acrylonitrile copolymer are melt-blended, the gel portion exists as a particulate dispersed phase in the continuous phase of the styrene-acrylonitrile copolymer. The gel content is obtained by dissolving the graft copolymer having a mass of W in methylethylene ketone, centrifuging at 20000 rpm using a centrifuge to precipitate the insoluble matter, and removing the supernatant by decantation to obtain the insoluble matter. It is a value calculated from the mass S of the dried insoluble matter after vacuum drying by the formula: gel content (mass%) = (S/W) x 100. Likewise, the gel content can be calculated by dissolving the resin composition obtained by melt-blending the graft copolymer and the styrene-acrylonitrile-based copolymer in methyl ethyl ketone and centrifuging.

The volume average particle size of the gel portion of the graft copolymer is preferably in the range of 0.10 to 1.0 μm, more preferably 0.15 to 0.1 μm, from the viewpoint of impact resistance and appearance of molded articles. 50 μm. The volume average particle size is obtained by cutting an ultra-thin section from a pellet of a resin composition obtained by melt-blending a graft copolymer and a styrene-acrylonitrile-based copolymer and observing it with a transmission electron microscope (TEM). It is a value calculated from image analysis of dispersed particles. The volume average particle size can be adjusted, for example, by the particle size of the latex of the rubber-like polymer used in the emulsion graft polymerization. The particle size of the latex of the rubber-like polymer can be adjusted by the addition method of the emulsifier and the amount of water used during the emulsion polymerization. There is a method in which a rubber-like polymer having a particle size of about 1 μm is polymerized in a short period of time and the rubber particles are enlarged by using a chemical coagulation method or a physical coagulation method.

From the viewpoint of impact resistance, the graft ratio of the graft copolymer is preferably 10 to 100% by mass, more preferably 20 to 70% by mass. The graft ratio is a value calculated from the gel content (G) and the content (RC) of the rubber-like polymer by graft ratio (% by mass)=[(G-RC)/R]×100. The graft ratio is determined by the styrene-acrylonitrile copolymer in which the particles of the rubber-like polymer are bonded by the graft contained per unit mass of the rubber-like polymer and the styrene-acrylonitrile-based copolymer included in the particles. represent quantity. For example, when emulsion graft polymerization is performed, the graft rate is determined by 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, and the charging method (batch/multistage/continuous). , the addition rate of the monomer, and the like.

The toluene swelling degree of the graft copolymer is preferably 5 to 20 times from the viewpoint of impact resistance and molded product appearance. The degree of swelling in toluene represents the degree of cross-linking of rubber-like polymer particles. is calculated from the mass ratio of the dry state after removing The degree of swelling of toluene is affected by, for example, the degree of cross-linking of the rubber-like polymer used in the emulsion graft polymerization, which depends on the initiator, emulsifier, polymerization temperature, divinylbenzene, etc. in the emulsion polymerization of the rubber-like polymer. It can be adjusted by adding a polyfunctional monomer or the like.

A SAN resin is a copolymer having styrene-based monomer units and acrylonitrile-based monomer units, for example, a styrene-acrylonitrile-based copolymer.

Other copolymerizable monomers for the SAN resin include (meth)acrylic acid ester-based monomers such as methyl methacrylate, acrylic acid ester-based monomers such as butyl acrylate and ethyl acrylate, methacrylic acid, and the like. (Meth)acrylic acid-based monomers, acrylic acid-based monomers such as acrylic acid, and N-substituted maleimide-based monomers such as N-phenylmaleimide can be used.

The constituent units of the SAN resin preferably contain 60 to 90% by mass of styrene monomer units and 10 to 40% by mass of vinyl cyanide monomer units, more preferably 65 to 80% by mass of styrene monomer units. % by mass, vinyl cyanide monomer unit is 20 to 35% by mass. If the structural unit is within the above range, the resulting resin composition will have an excellent balance between impact strength and fluidity. Styrenic monomer units and vinyl cyanide monomer units are values measured by 13C-NMR.

A known method can be adopted as the method for manufacturing the SAN resin. For example, it can be produced by bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, or the like. As for the operating method of the reactor, any of a continuous system, a batch system (batch system), and a semi-batch system can be applied. Bulk polymerization or solution polymerization is preferred from the aspects of quality and productivity, and continuous polymerization is preferred. Examples of solvents for bulk polymerization or solution polymerization include alkylbenzenes such as benzene, toluene, ethylbenzene and xylene, ketones such as acetone and methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and cyclohexane.

In 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. Polymerization initiators include, for example, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, 2,2-di(4,4-di-t-butyl peroxycyclohexyl)propane, peroxyketals such as 1,1-di(t-amylperoxy)cyclohexane, hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide, t-butyl peroxyacetate , alkyl peroxides such as t-amyl peroxy isononanoate, dialkyl peroxides such as t-butyl cumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, di-t-hexyl peroxide, Peroxy esters such as t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxy isopropyl monocarbonate, t-butyl peroxy isopropyl carbonate, polyether tetrakis (t-butyl peroxy carbonate) and the like Peroxycarbonates, N,N'-azobis(cyclohexane-1-carbonitrile), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylvaleronitrile) , N,N'-azobis[2-(hydroxymethyl)propionitrile] and the like, and these may be used alone or in combination of two or more. Chain transfer agents include, for example, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene and the like.

A well-known method can be adopted as a devolatilization method for removing volatile matter such as unreacted monomers and the solvent used for solution polymerization from the solution after polymerization of the SAN resin. For example, a vacuum devolatilization tank with a preheater or a devolatilization extruder with a vent can be used. The devolatilized molten SAN resin is transferred to a granulation step, extruded in a strand form from a multi-hole die, and processed into pellets by a cold cut method, an air hot cut method, or an underwater hot cut method.

The weight average molecular weight of the SAN resin is preferably 50,000 to 250,000, more preferably 70,000 to 200,000, from the viewpoint of impact resistance and moldability of the resin composition. Specifically, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 200,000. It may be in a range between the two. The weight average molecular weight of the SAN resin is a polystyrene-equivalent value measured in a THF solvent using gel permeation chromatography (GPC), and is a value measured in the same manner as for the maleimide-based copolymer (A). be. The weight average molecular weight can be adjusted by the type and amount of chain transfer agent during polymerization, solvent concentration, polymerization temperature, and type and amount of polymerization initiator.

As the ABS resin (B), for example, there is a method of using two types of powdery ABS resin obtained by an emulsion polymerization method and pellet-like SAN resin obtained by a continuous bulk polymerization method. Further, the powdery ABS resin obtained by emulsion polymerization and the pelletized SAN resin obtained by continuous bulk polymerization were once melt-blended using an extruder or the like to obtain a pelletized ABS resin (B). methods of using things.

A known method can be adopted as a method of melt-kneading the maleimide-based copolymer (A) and the ABS-based resin (B) using an extruder. A known extruder can be used, and examples thereof include a twin-screw extruder, a single-screw extruder, a multi-screw extruder, and a continuous kneader with a twin-screw rotor. From the viewpoint of being able to arbitrarily set the screw configuration and adjust the kneading property, it is preferable to use a twin-screw extruder, and an intermeshing co-rotating twin-screw extruder is generally widely used. used and more preferred.

Twin-screw extruder in the embodiment of the present invention, for example, as shown in FIG. 1, the space in which the cylinder is arranged is divided into a plurality of sections from the input section of the raw material to the discharge section, the temperature of each section is controlled It is configured so that it can be The cylinder temperature of the kneading section in the present invention is the set temperature of the section where the kneading section cylinder (mixing element) is arranged and which has the highest temperature among the sections where the material to be melt-kneaded is kneaded. The cylinder temperature in the kneading section of the extruder in an embodiment of the present invention is above 260°C, preferably 270-330°C. If the cylinder temperature of the kneading section is 260° C. or less, the dispersibility of the maleimide-based copolymer deteriorates, and the melt viscosity becomes too high, making extrusion difficult.

<4. Radical scavenger (C)>
Melt-kneading includes 2-t-butyl-6-(3′-t-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-[1-( It is carried out in the presence of at least one radical scavenger (C) selected from 3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylates. In the absence of the radical scavenger, the impact resistance of the heat-resistant resin composition is lowered. The radical scavenger (C) can be supplied to the extruder together with the maleimide-based copolymer (A) and the ABS-based resin (B) during melt-kneading in the extruder. Alternatively, it may be contained in advance in the maleimide-based copolymer (A) or the ABS-based resin (B).
The content of the radical scavenger (C) with respect to a total of 100 parts by mass of the maleimide copolymer (A) and the ABS resin (B) is preferably 0.1 to 0.6 parts by mass, and 0.2 parts by mass. More preferably, it is up to 0.4 parts by mass. Specifically, for example, it is 0.1, 0.2, 0.3, 0.4, 0.5 or 0.6, even if it is within the range between any two of the numerical values illustrated here good.
In addition, the content (mass ratio) of the polybutadiene component in the ABS resin to the radical scavenger (C) (polybutadiene content/radical scavenger (C)) is preferably 30 to 200, more preferably 50 to 110. is more preferred. Specifically, for example, 30, 35, 40, 45, 50, 55, 70, 80, 90, 100, 110, 120, 150, or 200, a range between any two of the numerical values exemplified here may be within

At the time of melt-kneading, an antioxidant can be used in combination, and it is preferable to use a hindered phenol-based antioxidant as the antioxidant, and a phosphorus-based antioxidant may be used in combination. Addition of an antioxidant can prevent yellowing or the like during molding of the heat-resistant resin composition or during actual use.

A hindered phenolic antioxidant is an antioxidant that has a phenolic hydroxyl group in its basic skeleton. Hindered phenolic antioxidants include, for example, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethylenebis(oxyethylene)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 tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,6-bis(octyl thiomethyl)-o-cresol, 4,6-bis[(dodecylthio)methyl]-o-cresol, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, tetrakis[methylene-3-(3, 5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 4,4′-thiobis(6-t-butyl-3-methylphenol), 1,1,3-tris(2-methyl-4- Hydroxy-5-t-butylphenyl)butane, 4,4′-butylidenebis(3-methyl-6-t-butylphenol), bis-[3,3-bis-(4′-hydroxy-3′-tert-butyl phenyl)-butanoic acid]-glycol ester, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy -3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate and the like. Preferably, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl) propionate], and pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. More preferred is octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. The hindered phenol-based antioxidants may be used alone or in combination of two or more.

Phosphorus-based antioxidants are phosphites, which are trivalent phosphorus compounds. Phosphorus-based antioxidants include, for example, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butylbenz [d, f ][1,3,2]dioxaphosphepine, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9- Diphosphaspiro[5.5]undecane, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 2,2′-methylenebis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyl) oxy) phosphorous, tris(2,4-di-tert-butylphenyl)phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, bis(2 ,4-di-tert-butylphenyl)pentaerythritol diphosphite, cyclic neopentanetetrayl bis(octadecylphosphite), bis(nonylphenyl)pentaerythritol diphosphite, 4,4'-biphenylene diphosphinic acid tetrakis ( 2,4-di-tert-butylphenyl), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(2,4-di-tert-butyl-5-methylphenyl)- 4,4'-biphenylene diphosphonite and the like. Preferably, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butylbenz[d,f][1,3, 2] dioxaphosphepine, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] Undecane, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 2,2′-methylenebis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus, tris ( 2,4-di-tert-butylphenyl)phosphite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite. More preferably, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butylbenz[d,f][1,3 ,2] dioxaphosphepine, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert -butylphenyl)pentaerythritol diphosphite, more preferably 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t -butylbenz[d,f][1,3,2]dioxaphosphepine, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)penta Erythritol diphosphite. Phosphorus-based antioxidants may be used alone or in combination of two or more.

When producing the heat-resistant resin composition, other resin components, impact modifiers, fluidity modifiers, hardness modifiers, antioxidants, inorganic fillers, luster are added to the extent that the effects of the present invention are not impaired. Extinguisher, flame retardant, auxiliary flame retardant, anti-drip agent, slidability agent, heat dissipation material, electromagnetic wave absorber, plasticizer, lubricant, release agent, ultraviolet absorber, light stabilizer, antibacterial agent, antifungal agent agents, antistatic agents, carbon black, titanium oxide, pigments, dyes and the like may be added.

Detailed contents will be described below using examples, but the present invention is not limited to the following examples.

<Production Example of Maleimide Copolymer (A-1)>
A maleimide-based copolymer (A-1) was produced by the following method.
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 placed in an autoclave having a volume of about 120 liters equipped with a stirrer. After charging and replacing the inside of the system with nitrogen gas, the temperature was raised to 92° C., and 28 parts by mass of maleic anhydride and 0.19 parts by mass of t-butyl peroxy-2-ethylhexanoate were added to 110 parts by mass of methyl ethyl ketone. The solution dissolved in parts was added continuously over 7 hours. After the addition, the temperature was raised to 120° C. and the reaction was allowed to proceed for 30 minutes to complete the polymerization. After that, 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. After completion of the reaction, the imidization reaction solution was charged into a vent-type screw extruder, and volatile matter was removed to obtain a maleimide copolymer (A-1) in the form of pellets. (A-1) contains 48% by mass of styrene units, 51% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units, has a weight average molecular weight Mw of 130,000, and has a glass transition temperature (midpoint glass transition temperature: Tmg) was 202°C.

<ABS resin (B-1)>
ABS resin (B-1) was prepared by an emulsion graft polymerization method. In a reactor equipped with a stirrer, 97 parts by mass of polybutadiene latex (solid content concentration 50 mass%, average particle diameter 0.3 μm), styrene content 24 mass% styrene-butadiene latex 12 parts by mass (solid content concentration 70 % by mass, average particle size is 0.5 μm), 1 part by mass of sodium stearate, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.01 part by mass of tetrasodium ethylenediamine tetraacetic acid, ferrous sulfate 0.005 parts by mass and 200 parts of pure water were charged and heated to 50°C. 43 parts by mass of a monomer mixture of 75% by mass of styrene and 25% by mass of acrylonitrile, 0.2 parts by mass of t-dodecylmercaptan, and 0.06 parts by mass of t-butyl peroxyacetate were continuously added in portions over 5 hours. did. After completion of the divisional addition, 0.04 part by mass of diisopropylene peroxide was added, and the polymerization was completed at 70° C. over an additional 2 hours to obtain a latex of ABS resin. After adding 0.3 parts of Irganox 1076 (manufactured by Ciba Specialty Chemical Co., Ltd.) to the obtained latex, magnesium sulfate and sulfuric acid are used to coagulate so that the pH of the slurry becomes 6.8 at the time of coagulation, followed by washing and dehydration. After that, it was dried to obtain a powdery ABS resin (B-1). The content of the rubber-like polymer is 57% by mass based on the blending ratio of the raw materials. The constituent units excluding the rubber-like polymer were measured by NMR to be 75% by mass of styrene units and 25% by mass of acrylonitrile units. Observation with a transmission electron microscope after making the resin composition revealed that the ABS resin was dispersed in the form of particles and had a volume average particle diameter of 0.4 μm.

<SAN Resin (B-2)>
A SAN resin (B-2) was produced by the following method.
It was produced by continuous bulk polymerization. Polymerization was carried out in a volume of 30 L using one complete mixing tank type agitating tank as a reactor. A raw material solution of 60% by mass of styrene, 22% by mass of acrylonitrile and 18% by mass of ethylbenzene was prepared and continuously supplied to the reactor at a flow rate of 9.5 L/h. In addition, t-butyl peroxyisopropyl monocarbonate as a polymerization initiator and n-dodecylmercaptan as a chain transfer agent were continuously added to the supply line of the raw material solution so as to have concentrations of 160 ppm and 400 ppm, respectively, to the raw material solution. The reaction temperature of the reactor was adjusted to 145°C. A polymer solution continuously taken out from the reactor was supplied to a vacuum devolatilization tank equipped with a preheater to separate unreacted styrene, acrylonitrile and ethylbenzene. The temperature of the preheater was adjusted so that the polymer temperature in the devolatilization tank was 235° C., and the pressure in the devolatilization tank was 0.4 kPa. The polymer was extracted from the vacuum devolatilization tank by a gear pump, extruded into strands, cooled with cooling water, and cut to obtain SAN resin (B-2) in the form of pellets. The constituent units of (B-2) were 73.5% by mass of styrene units and 26.5% by mass of acrylonitrile units. Moreover, the weight average molecular weight was 146,000.

<ABS resin (B-3)>
A commercially available ABS resin GR-3000 (manufactured by Denka Co., Ltd.) was used.

<Example/Comparative example>
A maleimide copolymer, an ABS resin, a radical scavenger, and an antioxidant were melt-kneaded using an extruder under the formulations and conditions shown in Table 1 to produce a heat-resistant resin composition. As the extruder, a twin-screw extruder (TEM-35B manufactured by Toshiba Machine Co., Ltd.) is used, and the cylinder temperature in the kneading section shown in Table 1, the screw rotation speed is 250 rpm, and the feed rate is 30 kg / hr Extrusion was performed. rice field. The radical scavengers and antioxidants used are as follows. Table 1 shows the evaluation results. In Comparative Example 3, the cylinder temperature in the kneading section was low, and the extrusion at the specified discharge rate was impossible due to torque over.
(C-1) 2-t-butyl-6-(3′-t-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate (Sumilizer GS manufactured by Sumitomo Chemical Co., Ltd.)
(C-2) 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate (Sumilizer GM manufactured by Sumitomo Chemical Co., Ltd.)
(D-1) Pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010 manufactured by BASF Japan Ltd.)
(D-2) Tris (2,4-di-tert-butylphenyl) phosphite (Irgafos 168 manufactured by BASF Japan Ltd.)

(melt mass flow rate)
The melt mass flow rate was measured at 220° C. under a load of 98 N according to JIS K7210.

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

(Charpy impact strength)
The Charpy impact strength was measured according to JIS K7111-1, using notched test pieces and adopting an edgewise impact direction. A digital impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd. was used as the measuring machine.

(hue YI value)
A plate (9 cm×5 cm) was molded at a molding temperature of 240° C. with an injection molding machine IS-50EP (manufactured by Toshiba Machine Co., Ltd.), and the yellowness index YI was measured with a color difference meter COLOR-7e2 (manufactured by Kurashiki Boseki Co., Ltd.).

From the results in Table 1, in order to melt-knead the heat-resistant resin composition, it is necessary to set the cylinder temperature of the kneading unit higher, but by melt-kneading in the presence of a radical scavenger, impact resistance It can be found that it becomes possible to produce a heat-resistant resin composition excellent in

According to the production method of the present invention, a heat-resistant resin composition with excellent impact resistance can be obtained even if the maleimide-based copolymer and the ABS-based resin are melt-kneaded at a high processing temperature. Since melt-kneading is possible at a high processing temperature, a maleimide copolymer with high heat resistance can be used, and the heat resistance of ABS resin can be improved with a small addition amount. In addition, it becomes possible to increase the blending amount of the maleimide-based copolymer having high melt viscosity, and it becomes possible to produce a heat-resistant resin composition having high heat resistance.

Claims

A method for producing a heat-resistant resin composition comprising a step of melt-kneading a maleimide-based copolymer (A) and an ABS-based resin (B) with an extruder, wherein the melt-kneading is performed by 2-t-butyl- 6-(3′-t-butyl-5′-methyl-2′-hydroxybenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl- A method for producing a heat-resistant resin composition, carried out in the presence of at least one radical scavenger (C) selected from 2-hydroxyphenyl)ethyl]phenyl acrylate.
2. The method for producing a heat-resistant resin composition according to claim 1, wherein the melt-kneading is performed at a cylinder temperature exceeding 260[deg.] C. in the kneading section of the extruder.
The method for producing a heat-resistant resin composition according to claim 1 or 2, wherein the maleimide-based copolymer (A) has a glass transition temperature of 175°C to 210°C.
Claims 1 to 1, wherein the content of the radical scavenger (C) is 0.1 to 0.6 parts by mass with respect to a total of 100 parts by mass of the maleimide copolymer (A) and the ABS resin (B). 4. A method for producing a heat-resistant resin composition according to any one of 3.
The method for producing a heat-resistant resin composition according to any one of claims 1 to 4, wherein the extruder is a twin-screw extruder.
The method for producing a heat-resistant resin composition according to any one of claims 1 to 5, wherein the heat-resistant resin composition has a Vicat softening temperature of 115°C or higher.
The melt-kneading is performed in the presence of two or more antioxidants (D) selected from hindered phenol antioxidants and phosphorus antioxidants, according to any one of claims 1 to 6. A method for producing the heat-resistant resin composition described.