ABS resin modifier, resin composition, molded article, and method for producing resin composition

Abstract

The present invention addresses the problem of providing an ABS resin modifier which improves ABS resin impact resistance and chemical resistance. Provided is an ABS resin modifier which contains a maleimide resin (A) having a maleimide monomer unit, a styrene monomer unit and an unsaturated dicarboxlyic acid anhydride monomer unit, and also contains a polyamide resin (B), said ABS resin modifier having a dispersed phase which has an average particle diameter of 100nm or less.

Description

Technical Field

[0001] The present invention relates to an ABS resin modifier, a resin composition containing the ABS resin modifier, a molded article obtained by molding the resin composition, and a method for producing the resin composition.

Background Art

[0002] ABS resin is a thermoplastic resin mainly composed of acrylonitrile, butadiene, and styrene. Taking advantage of its excellent mechanical strength, appearance, chemical resistance, moldability, etc., it is widely used in automobiles, home appliances, OA equipment, housing building materials, daily necessities, etc. It is known that adding a polyamide resin and a compatibilizer to the ABS resin can enhance its chemical resistance and impact resistance (Patent Document 1, Patent Document 2). However, if the content of the polyamide resin is low, it is difficult to achieve both chemical resistance and impact resistance, and if it is high, the moisture absorption dimensional stability may be inferior.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide an ABS resin modifier that improves the impact resistance and chemical resistance of an ABS resin.

Means for Solving the Problems

[0005] (1) An ABS resin modifier comprising a maleimide resin (A) having a maleimide monomer unit, a styrene monomer unit, and an unsaturated dicarboxylic anhydride monomer unit, and a polyamide resin (B), wherein the ABS resin modifier has a dispersed phase, and the average particle diameter of the dispersed phase is 100 nm or less. (2) The ABS resin modifier according to (1), wherein when the maleimide resin (A) is 100% by mass, the maleimide resin (A) contains 1 to 10% by mass of the unsaturated dicarboxylic anhydride monomer unit. (3) The ABS resin modifier according to (1) or (2), wherein the tensile fracture elongation measured at a tensile speed of 50 mm / min of a test piece conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity based on JIS K7161 is 10% or more. (4) A resin composition comprising the ABS resin modifier according to any one of (1) to (3) and at least one resin (C) selected from the group consisting of an ABS resin, a SAN resin, an ASA resin, and an AES resin. (5) The resin composition according to (4), wherein when the entire resin composition is 100% by mass, the polyamide resin (B) contained in the resin composition is less than 20% by mass. (6) The resin composition according to (4) or (5), wherein the Charpy impact strength measured using a notched test piece conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity based on JIS K7111-1 and adopting edgewise as the impact direction is 12 KJ / m 2 or more. (7) A method for producing a resin composition, comprising a step of melt-kneading a raw material containing the ABS resin modifier according to any one of (1) to (3) and at least one resin (C) selected from the group consisting of an ABS resin, a SAN resin, an ASA resin, and an AES resin in an extruder. (8) A molded article obtained by molding the resin composition according to any one of (4) to (6).

Advantages of the Invention

[0006] By adding the ABS resin modifier of the present invention to at least one resin selected from ABS resin, SAN resin, ASA resin, and AES resin, a resin composition excellent in chemical resistance and impact resistance can be obtained.

Embodiments for Carrying Out the Invention

[0007] <Explanation of Terms> In the specification of the present application, for example, the description "A to B" means A or more and B or less.

[0008] Hereinafter, embodiments of the present invention will be described in detail.

[0009] The ABS resin modifier of the present embodiment contains a maleimide-based resin (A) and a polyamide resin (B). The ABS resin modifier of the present embodiment is preferably obtained by melt-kneading a raw material containing a maleimide-based resin (A) and a polyamide resin (B).

[0010] The maleimide-based resin (A) has a maleimide-based monomer unit, a styrene-based monomer unit, and an unsaturated dicarboxylic anhydride-based monomer unit. The maleimide-based resin (A) may have monomer units other than the maleimide-based monomer unit, the styrene-based monomer unit, and the unsaturated dicarboxylic anhydride-based monomer unit. For example, it can further have a vinyl cyanide monomer unit.

[0011] The maleimide-based monomer unit is, for example, 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 these, N-phenyl maleimide is preferred. The maleimide-based monomer unit may be used alone or in combination of two or more. For the maleimide-based monomer unit, for example, a raw material composed of a maleimide-based monomer can be used. Or it can be obtained by imidizing a raw material composed of an unsaturated dicarboxylic anhydride-based monomer unit with ammonia or a primary amine.

[0012] The styrene monomer unit is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, etc. Among these, styrene is preferred. The styrene monomer unit may be used alone or in combination of two or more.

[0013] The unsaturated dicarboxylic anhydride monomer unit is maleic anhydride, itaconic anhydride, citraconic anhydride, aconitic anhydride, etc. Among these, maleic anhydride is preferred. The unsaturated dicarboxylic anhydride monomer unit may be used alone or in combination of two or more.

[0014] The vinyl cyanide monomer unit is acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, etc. Among these, acrylonitrile is preferred. The vinyl cyanide monomer unit may be used alone or in combination of two or more.

[0015] The weight average molecular weight (Mw) of the maleimide resin (A) is preferably 80,000 to 180,000, and more preferably in the range of 130,000 to 160,000. If the weight average molecular weight (Mw) is too small, the impact strength of the resin composition obtained using the ABS resin modifier may decrease. If it is too large, the fluidity of the resin composition obtained using the ABS resin modifier may decrease and the moldability may deteriorate. To control the weight average molecular weight (Mw) of the maleimide resin (A), in addition to adjusting the polymerization temperature, polymerization time, and polymerization initiator addition amount, methods such as adjusting the solvent concentration and chain transfer agent addition amount can be used. The weight average molecular weight of the maleimide resin (A) is a value in terms of polystyrene measured by gel permeation chromatography (GPC) and was measured under the following conditions. Apparatus name: SYSTEM-21 Shodex (manufactured by Showa Denko KK) Column: Three PL gel MIXED-B columns in series Temperature: 40 °C Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2 mass% Calibration curve: Prepared using standard polystyrene (PS) (manufactured by Polymer Laboratories).

[0016] The amount of styrenic monomer units contained in the maleimide resin (A) is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, when the total amount of the maleimide resin (A) is 100% by mass. For example, it can be 30, 35, 40, 45, 50, 55, 60, 65, 70% by mass, and can also be within the range between any two of the exemplified values. If the content of styrenic monomer units is too small, the compatibility with the ABS resin may deteriorate, and the effect as an ABS resin modifier may not be fully exerted. If it is too large, the dispersed phase in the ABS resin modifier may become large.

[0017] The amount of unsaturated dicarboxylic anhydride-based monomer units contained in the maleimide resin (A) is preferably 1 to 10% by mass, more preferably 1 to 7% by mass, when the total amount of the maleimide resin (A) is 100% by mass. For example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10% by mass, and can also be within the range between any two of the exemplified values. If the amount of unsaturated dicarboxylic anhydride-based monomer units is too small, the impact strength of the resin composition may decrease. If it is too large, the fluidity of the resin composition may decrease and the moldability may deteriorate. The amount of unsaturated dicarboxylic anhydride-based monomer units is a value measured by a titration method. Also, as described later, by appropriately controlling the unsaturated dicarboxylic anhydride-based monomer units and the like contained in the maleimide resin (A), it becomes easier to control the average particle diameter of the dispersed phase.

[0018] When the amount of the maleimide monomer unit contained in the maleimide resin (A) is based on 100% by mass of the entire maleimide resin (A), it is preferably 10% to 68% by mass. If the content of the maleimide monomer unit is less than 10% by mass or more than 68% by mass, the compatibility with the ABS resin may deteriorate, and the effect as an ABS resin modifier may not be fully exerted. The content of the maleimide monomer unit is particularly preferably 30% to 58% by mass or less. The content of the maleimide monomer unit is, for example, 10, 20, 30, 40, 50, 60, 68% by mass, and may also be within the range between any two of the numerical values exemplified herein.

[0019] When the total amount of the styrene monomer unit, the unsaturated dicarboxylic anhydride monomer unit, and the maleimide monomer unit contained in the maleimide resin (A) is based on 100% by mass of the entire maleimide resin (A), it is preferably 90% by mass or more. The maleimide resin (A) can also be composed only of a styrene monomer unit, an unsaturated dicarboxylic anhydride monomer unit, a maleimide monomer unit, and a vinyl cyanide monomer unit. Further, the maleimide resin (A) can also be composed only of a styrene monomer unit, an unsaturated dicarboxylic anhydride monomer unit, and a maleimide monomer unit.

[0020] The midpoint glass transition temperature (Tmg) of the maleimide resin (A) is preferably 170 to 210 °C, more preferably 175 to 205 °C. The midpoint glass transition temperature (Tmg) of the maleimide resin (A) is a value measured by DSC in accordance with JIS K-7121 and is a measured value under the measurement conditions described below. Apparatus name: Robot DSC6200 manufactured by Seiko Instruments Inc. Heating rate: 10 °C / min

[0021] As a method for producing the maleimide resin (A), a known method can be adopted. For example, there is a method of copolymerizing a monomer mixture composed of a styrene monomer, a maleimide monomer, an unsaturated dicarboxylic anhydride monomer, and other copolymerizable monomers. Further, after copolymerizing a monomer mixture composed of a styrene monomer, an unsaturated dicarboxylic anhydride monomer, and other copolymerizable monomers, a part of the unsaturated dicarboxylic anhydride monomer units is reacted with ammonia or a primary amine for imidization to be converted into maleimide monomer units (hereinafter referred to as the "post-imidization method").

[0022] The polymerization mode of the maleimide resin (A) includes, for example, solution polymerization, bulk polymerization, etc. From the viewpoint of making the copolymer composition more uniform by performing fractionation or the like during polymerization, solution polymerization is preferred. The solvent for solution polymerization is preferably non-polymerizable from the viewpoint of being less likely to produce by-products and having few adverse effects. 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 ease of solvent removal during devolatilization recovery of the maleimide resin, methyl ethyl ketone and methyl isobutyl ketone are preferred. The polymerization process can be any of a continuous polymerization type, a batch type (batch process), and a semi-batch type. The polymerization method is not particularly limited, but radical polymerization is preferred from the viewpoint of being able to produce with high productivity by a simple process.

[0023] In solution polymerization or bulk polymerization, a polymerization initiator and a chain transfer agent can be used, and the polymerization temperature is preferably in the range of 80 to 150 °C. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobis(methylpropionitrile), azobis(methylbutyronitrile), and peroxides such as benzoyl peroxide, t-butyl peroxybenzoate, 1,1-di(t-butylperoxy)cyclohexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxide, dicumyl peroxide, ethyl 3,3-di-(t-butylperoxy)butyrate. One or more of these may be used in combination. From the viewpoints of the reaction rate of polymerization and the control of the polymerization rate, 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 preferably 0.1 to 1.5 parts by mass, more preferably 0.1 to 1.0 parts by mass, based on 100 parts by mass of the total monomer units. If the amount of the polymerization initiator used is 0.1 part by mass or more, a sufficient polymerization rate can be obtained, which is preferable. If the amount of the polymerization initiator used is 1.5 parts by mass or less, the polymerization rate can be suppressed, so that the reaction control becomes easy and the target molecular weight can be easily obtained. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene, etc. The amount of the chain transfer agent used is not particularly limited as long as the target molecular weight can be obtained, but it is preferably 0.1 to 0.8 parts by mass, more preferably 0.15 to 0.5 parts by mass, based on 100 parts by mass of the total monomer units. If the amount of the chain transfer agent used is 0.1 part by mass to 0.8 parts by mass, the target molecular weight can be easily obtained.

[0024] The introduction of maleimide monomer units into the maleimide resin (A) can be achieved by copolymerizing maleimide monomers or by a post-imidation method. The post-imidation method is preferred because it reduces the amount of residual maleimide monomers in the maleimide resin (A). The post-imidation method involves copolymerizing a monomer mixture consisting of styrene monomers, unsaturated dicarboxylic anhydride monomers, and other copolymerizable monomers, and then reacting a part of the unsaturated dicarboxylic anhydride monomer units with ammonia or a primary amine to cause imidization and convert them into maleimide monomer units. Examples of primary amines include alkylamines such as methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, decylamine, and chlorinated or brominated alkylamines, as well as aromatic amines such as aniline, toluidine, and naphthylamine. Among these, aniline is preferred. These primary amines can be used alone or in combination of two or more. During post-imidation, a catalyst can be used in the reaction between the primary amine and the unsaturated dicarboxylic anhydride monomer units to improve the dehydration ring-closure reaction. Examples of catalysts include tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, and N,N-diethylaniline. The temperature for post-imidation is preferably 100 to 250°C, more preferably 120 to 200°C. If the temperature of the imidization reaction is 100°C or higher, the reaction rate is improved, which is preferable from the perspective of productivity. If the temperature of the imidization reaction is 250°C or lower, it is preferable because it can suppress the deterioration of physical properties due to thermal degradation of the maleimide resin (A).

[0025] After the solution polymerization of the maleimide resin (A) is completed or after the post-imidation is completed, a known method (degassing method) can be adopted to remove volatile components such as the solvent used in the solution polymerization and unreacted monomers from the solution. For example, a vacuum degassing tank equipped with a heater or a degassing extruder with a vent can be used. The degassed molten maleimide resin (A) is transferred to a granulation process, extruded in a strand shape from a porous die, and can be processed into pellets by a cold cut method, an air hot cut method, or a water hot cut method.

[0026] The amount of maleimide monomer remaining in the maleimide resin (A) is preferably 300 ppm or less, more preferably 250 ppm or less. If the amount of maleimide monomer remaining is within the above range, the hue of the maleimide resin (A) is excellent. The amount of maleimide monomer remaining can be adjusted according to the polymerization conditions and degassing conditions, and is a value quantified using the reprecipitation method.

[0027] The polyamide resin (B) is a resin having an amide bond in the main chain, and examples include nylon-6, nylon-6,6, nylon-4,6, nylon-6,7, nylon-6,10, nylon-11, nylon-12, etc. Among these, nylon-11 is preferred. The polyamide resin (B) may be used alone or in combination of two or more.

[0028] The molecular weight of the polyamide resin (B) is not particularly limited. From the perspective of fluidity, at 270 °C, the melt viscosity under the condition of a shear rate of 100 sec-1 is preferably 50 to 200 Pa·s, more preferably 75 to 175 Pa·s, and even more preferably 100 to 125 Pa·s. The polyamide resin (B) preferably has an end amino group content of 2.0 to 4.0 mgKOH / g. For example, it can be 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0 mgKOH / g, and it may also be within the range between any two of the values exemplified herein. As described later, by appropriately controlling the type and amount of the formulation containing the amount of the end amino group of the polyamide resin (B) and the manufacturing conditions, etc., it becomes easier to control the average particle diameter of the dispersed phase.

[0029] When the total amount of the ABS resin modifier is 100 parts by mass, the content of the maleimide resin (A) in the ABS resin modifier is preferably 10 to 50% by mass, more preferably 15 to 40% by mass. For example, it can be 10, 15, 20, 30, 40, or 50% by mass, and it may also be within the range between any two of the values exemplified herein. When the total amount of the ABS resin modifier is 100 parts by mass, the content of the polyamide resin (B) in the ABS resin modifier is preferably 50 to 90% by mass, more preferably 60 to 80% by mass. For example, it can be 50, 60, 70, 80, or 90% by mass, and it may also be within the range between any two of the values exemplified herein. When the total amount of the ABS resin modifier is 100 parts by mass, the total content of the maleimide resin (A) and the polyamide resin (B) in the ABS resin modifier can be 90% by mass or more, preferably 95% by mass or more, and more preferably 98% by mass or more. The ABS resin modifier can also consist only of the maleimide resin (A) and the polyamide resin (B). If the content of the maleimide resin (A) is too low, the compatibility with the resin (C) will decrease. If it is too high, the fluidity when compounded with the resin (C) will decrease, and the moldability may deteriorate.

[0030] The ABS resin modifier according to an embodiment of the present invention has a dispersed phase. It is preferable that the ABS resin modifier has a sea-island dispersion structure in which the maleimide resin (A) and the polyamide resin (B) are in the form of a sea-island dispersion structure. The dispersed phase (island) contains the maleimide resin (A), and the matrix phase (sea) contains the polyamide resin (B). The dispersed phase (island) preferably consists essentially of the maleimide resin (A), and the matrix phase (sea) preferably consists essentially of the polyamide resin (B). The average particle diameter of the dispersed phase is 100 nm or less, preferably 80 nm or less. Also, the average particle diameter of the dispersed phase can be 10 nm or more. The average particle diameter of the dispersed phase is, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 nm, and may be within the range between any two of the values exemplified herein. If the average particle diameter of the dispersed phase is larger than 100 nm, the impact resistance and chemical resistance of the resin composition may decrease. The average particle diameter of the dispersed phase is calculated by observing the ABS resin modifier with a transmission electron microscope (TEM), calculating the diameter (equivalent circle diameter) from the area for each dispersed phase, and is the number average value of the diameters.

[0031] The average particle diameter of the dispersed phase can be easily controlled by adjusting the amount of the unsaturated carboxylic anhydride monomer unit contained in the maleimide resin (A) and the amount of the terminal amino groups of the polyamide resin (B). That is, in the ABS resin modifier according to one embodiment of the present invention, it is considered that the more the amount of the unsaturated dicarboxylic anhydride-based monomer unit contained in the maleimide resin (A) reacts with the terminal amino groups contained in the polyamide resin (B), the smaller the average particle diameter of the dispersed phase becomes. Further, it is considered that the reaction rate varies depending on the mobility and viscosity of the polymer chains of the maleimide resin (A) and the polyamide resin (B), and the kneading conditions of the maleimide resin (A) and the polyamide resin (B). The ABS resin modifier according to one embodiment of the present invention can control the average particle diameter of the dispersed phase within an appropriate numerical range by adjusting the content of the unsaturated dicarboxylic anhydride-based monomer unit contained in the maleimide resin (A), the amount of the terminal amino groups contained in the polyamide resin (B), the polymer characteristics related to reactivity, and the kneading conditions of the maleimide resin (A) and the polyamide resin (B). Further, since such an ABS resin modifier has a high degree of dispersibility, it is presumed that when added to an ABS resin or the like, a resin composition excellent in chemical resistance and impact resistance can be obtained.

[0032] The ABS resin modifier according to one embodiment of the present invention preferably has a tensile fracture nominal strain of 10% or more, preferably 30% or more, preferably 50% or more, and more preferably 70% or more. The upper limit is not particularly limited, and for example, it can be 200%. Here, the tensile fracture nominal strain can be measured at a tensile speed of 50 mm / min based on JIS K7161, and as the test piece, one that has been conditioned in a thermostatic chamber at 23°C and a humidity of 50% for 16 hours can be used.

[0033] The ABS resin modifier according to one embodiment of the present invention preferably has a Charpy impact strength of 4 KJ / m 2 or more, preferably 5 KJ / m 2 or more, preferably 6 KJ / m 2 and preferably 7 KJ / m 2It is more preferable that it is. The upper limit is not particularly limited, for example, 20 KJ / m 2 It can be set as such. Here, the Charpy impact strength can be measured based on JIS K7111-1 using a notched test piece and adopting an edgewise impact direction. As the test piece, one that has been conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity can be used. Note that, for example, a digital impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd. can be used as the measuring machine.

[0034] As the method for melt-kneading the maleimide resin (A) and the polyamide resin (B), a known method can be adopted, for example, melt-kneading using an extruder. As the extruder, a known device can be used, for example, a twin-screw extruder, a single-screw extruder, a multi-screw extruder, a continuous kneader with a twin-shaft rotor, etc. can be mentioned. A meshing co-rotating twin-screw extruder is generally widely used and can be preferably used. Also, a plurality of these extruders can be combined and used. There are no particular restrictions on the extruder and the extrusion temperature, but from the viewpoint of making the particle diameter of the dispersed phase of the ABS resin modifier 100 nm or less, it is preferable to use a twin-screw extruder and perform melt-kneading at 260°C to 320°C. Depending on other manufacturing conditions, the screw rotation speed can be, for example, 150 to 350 rpm, and the extrusion amount can be 15 to 35 kg / hr.

[0035] The resin composition according to one embodiment of the present invention contains the ABS resin modifier described above and at least one resin (C) selected from an ABS resin, a SAN resin, an ASA resin, and an AES resin. The resin composition according to one embodiment of the present invention is a resin composition obtained by melt-kneading a raw material containing the ABS resin modifier described above and at least one resin (C) selected from an ABS resin, a SAN resin, an ASA resin, and an AES resin. The ABS resin modifier has the effect of improving the impact resistance and chemical resistance of resin (C). Resin (C) preferably contains at least one of an ABS resin and a SAN resin, more preferably contains both an ABS resin and a SAN resin, and can also consist only of an ABS resin and a SAN resin. As resin (C), for example, two types, a powdery ABS resin obtained by an emulsion polymerization method and a pellet-like SAN resin obtained by a continuous bulk polymerization method, may be used. Alternatively, a powdery ABS resin obtained by an emulsion polymerization method and a pellet-like SAN resin obtained by continuous bulk polymerization may be melt-blended in advance using an extruder or the like to form a pellet-like ABS resin for use.

[0036] When the total amount of the resin composition is taken as 100% by mass, the content of the ABS resin modifier in the resin composition is preferably 5 to 20% by mass, more preferably 10 to 15% by mass, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20% by mass, and may be within the range between any two of the values exemplified herein.

[0037] In the resin composition according to one embodiment of the present invention, when the total amount of the resin composition is taken as 100% by mass, the polyamide resin contained in the resin composition is preferably less than 20% by mass, more preferably 15% by mass or less, and preferably less than 10% by mass, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20% by mass, and may be within the range between any two of the values exemplified herein. When the ABS resin modifier according to one embodiment of the present invention is used, a resin composition having sufficient chemical resistance and impact resistance can be obtained even when the content of the polyamide resin in the resin composition is made less than before, and a decrease in moisture absorption dimensional stability that may occur when the content of the polyamide resin is high can be prevented.

[0038] ABS resin, ASA resin, and AES resin are graft copolymers obtained by graft copolymerizing at least a styrene-based monomer and an acrylonitrile-based monomer onto a rubber-like polymer. For example, when using a butadiene-based rubber such as polybutadiene or a styrene-butadiene copolymer as the rubber-like polymer, it is an ABS resin; when using an acrylic rubber composed of butyl acrylate, ethyl acrylate, etc., it is an ASA resin; when using an ethylene-based rubber such as an ethylene-α-olefin copolymer, it is an AES resin. Two or more of these rubber-like polymers may be combined and used during the graft copolymerization.

[0039] As a method for producing the graft of ABS resin and the like, a known method can be adopted. For example, methods such as emulsion polymerization and continuous bulk polymerization can be mentioned. The method by emulsion polymerization is preferable because it is easy to adjust the content of the rubber-like polymer in the final resin composition.

[0040] A method for producing a graft copolymer by emulsion polymerization is a method of emulsion graft copolymerizing a styrene-based monomer and an acrylonitrile-based monomer onto a latex of a rubber-like polymer (hereinafter referred to as the "emulsion graft polymerization method"). By the emulsion graft polymerization method, a latex of the graft copolymer can be obtained.

[0041] 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, cationic surfactants, amphoteric surfactants, and the like. Examples of the polymerization initiator include organic peroxides such as cumene hydroperoxide, diisopropylbenzene peroxide, t-butyl peroxyacetate, t-hexyl peroxybenzoate, t-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, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene, and the like.

[0042] The latex of the graft copolymer 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 for coagulation, followed by washing and dehydration with a dehydrator and passing through a drying process to obtain a powdery graft copolymer.

[0043] From the viewpoint of impact resistance, the content of the rubbery 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. The content of the rubbery polymer can be adjusted, for example, by the usage ratio of the styrene-based monomer and the acrylonitrile-based monomer with respect to the rubbery polymer during the emulsion graft polymerization.

[0044] From the viewpoints of impact resistance and chemical resistance, the content of the constitutional units excluding the rubbery polymer in the graft copolymer obtained by the emulsion graft polymerization method is preferably 65 to 85% by mass of styrene-based monomer units and 15 to 35% by mass of acrylonitrile-based monomer units.

[0045] The gel fraction of the graft copolymer is preferably in the form of particles. The gel fraction refers to particles of a rubbery polymer obtained by graft copolymerization of a styrene monomer and an acrylonitrile monomer, and is a component that is insoluble in organic solvents such as methyl ethyl ketone and toluene and is separated by centrifugation. An occlusion structure may be formed in which a styrene-acrylonitrile copolymer is encapsulated in a particulate form inside the particles of the rubbery polymer. When the graft copolymer and the styrene-acrylonitrile copolymer are melt-blended, the gel fraction exists as a particulate dispersed phase in the continuous phase of the styrene-acrylonitrile copolymer. The gel fraction is obtained by dissolving a graft copolymer of mass W in methyl ethyl ketone, centrifuging at 20,000 rpm using a centrifuge to precipitate the insoluble matter, removing the supernatant by decantation to obtain the insoluble matter, and calculating from the mass S of the dried insoluble matter after vacuum drying, the gel fraction (% by mass) = (S / W) × 100. Also, for a polymer blend obtained by melt-blending a graft copolymer and a styrene-acrylonitrile copolymer, the gel fraction can be calculated in the same way by dissolving it in methyl ethyl ketone and centrifuging.

[0046] The number-average particle diameter of the gel fraction of the graft copolymer is preferably in the range of 0.10 to 1.0 μm, more preferably 0.15 to 0.50 μm, from the viewpoints of impact resistance and the appearance of the molded article. The number-average particle diameter is a value calculated from image analysis of particles dispersed in the continuous phase by cutting out ultrathin sections from pellets of a polymer blend obtained by melt-blending a graft copolymer and a styrene-acrylonitrile copolymer and observing with a transmission electron microscope (TEM). The number-average particle diameter can be adjusted, for example, by the particle diameter of the latex of the rubbery polymer used during emulsion graft polymerization. The particle diameter of the latex of the rubbery polymer can be adjusted by the method of adding an emulsifier and the amount of water used during emulsion polymerization, but in order to obtain a preferable range, since the polymerization time is long and the productivity is low, there is a method of polymerizing a rubbery polymer having a particle diameter of around 0.1 μm in a short time and enlarging the rubber particles using a chemical aggregation method or a physical aggregation method.

[0047] The grafting ratio of the graft copolymer is preferably 10 to 100% by mass, more preferably 20 to 70% by mass, from the viewpoint of impact resistance. The grafting ratio is a value calculated by grafting ratio (% by mass) = [(G - RC) / RC] × 100 from the gel content (G) and the content of the rubber-like polymer (RC). The grafting ratio represents the amount of the styrene-acrylonitrile copolymer bonded by the graft contained per unit mass of the rubber-like polymer particles and the styrene-acrylonitrile copolymer encapsulated in the particles. The grafting ratio can be adjusted, for example, 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, the charging method (batch / multistage / continuous), the addition rate of the monomer, etc. when emulsion graft polymerization is carried out.

[0048] The toluene swelling degree of the graft copolymer is preferably 5 to 20 times from the viewpoints of impact resistance and the appearance of the molded product. The toluene swelling degree represents the degree of crosslinking of the rubber-like polymer particles, and is calculated from the mass ratio of the state swollen with toluene to the mass of the dried state from which toluene has been removed by vacuum drying after dissolving the graft copolymer in toluene and separating the insoluble matter by centrifugation or filtration. The toluene swelling degree is affected by, for example, the degree of crosslinking of the rubber-like polymer used in emulsion graft polymerization, and this can be adjusted by the initiator, emulsifier, polymerization temperature, addition of polyfunctional monomers such as divinylbenzene, etc. during the emulsion polymerization of the rubber-like polymer.

[0049] The SAN resin is a copolymer having a styrene monomer unit and an acrylonitrile monomer unit, and for example, there is a styrene-acrylonitrile copolymer.

[0050] As other copolymerizable monomers of the SAN resin, (meth)acrylate monomers such as methyl methacrylate, acrylate monomers such as butyl acrylate and ethyl acrylate, (meth)acrylic acid monomers such as methacrylic acid, acrylic acid monomers such as acrylic acid, N-substituted maleimide monomers such as N-phenylmaleimide can be used.

[0051] The constituent units of the SAN resin preferably contain 60 to 90% by mass of styrenic monomer units and 10 to 40% by mass of vinyl cyanide monomer units, more preferably 65 to 80% by mass of styrenic monomer units and 20 to 35% by mass of vinyl cyanide monomer units. If the constituent units are within the above ranges, the balance between the impact strength and fluidity of the resulting resin composition is excellent. The styrenic monomer units and vinyl cyanide monomer units are values measured by 13C-NMR.

[0052] As a method for producing the SAN resin, a known method can be adopted. For example, it can be produced by bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. As the operation method of the reaction apparatus, any of continuous, batch (batchwise), and semi-batch methods can be applied. From the viewpoints of quality and productivity, bulk polymerization or solution polymerization is preferred, and a continuous method is preferred. Examples of the solvent 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.

[0053] 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 peroxyketals such as 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, 2,2-di(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-di(t-amylperoxy)cyclohexane; hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide; alkyl peroxides such as t-butyl peroxyacetate, t-amyl peroxyisooctanoate; dialkyl peroxides such as t-butylcumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, di-t-hexyl peroxide; peroxy esters such as t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl monocarbonate; peroxy carbonates such as t-butyl peroxyisopropyl carbonate, polyether tetrakis(t-butyl peroxycarbonate); and N,N'-azobis(cyclohexane-1-carbonitrile), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylvaleronitrile), N,N'-azobis[2-(hydroxymethyl)propionitrile]. One or a combination of two or more of these can be used. Examples of the chain transfer agent include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene, etc.

[0054] For the devolatilization method of removing volatile components such as unreacted monomers and solvents used in solution polymerization from the solution after the polymerization of SAN resin, known methods can be adopted. 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 process, extruded in a strand shape through a porous die, and can be processed into pellets by a cold cut method, an air hot cut method, or a water hot cut method.

[0055] From the viewpoints of the impact resistance and moldability of the 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. The weight average molecular weight of the SAN resin is a value in terms of polystyrene measured in a THF solvent using gel permeation chromatography (GPC), and is a value measured in the same manner as the maleimide resin (A). The weight average molecular weight can be adjusted by the type and amount of the chain transfer agent during polymerization, the solvent concentration, the polymerization temperature, and the type and amount of the polymerization initiator.

[0056] As a method for producing the resin composition according to an embodiment of the present invention, there is mentioned a method including a step of melt-kneading a raw material containing the above-described ABS resin modifier and at least one resin (C) selected from an ABS resin, a SAN resin, an ASA resin, and an AES resin. As a method for melt-kneading the ABS resin modifier and at least one resin (C) selected from an ABS resin, a SAN resin, an ASA resin, and an AES resin, a known method can be employed, for example, melt-kneading by an extruder. As the extruder, a known apparatus can be used, for example, a twin-screw extruder, a single-screw extruder, a multi-screw extruder, a continuous kneader with a twin-rotor, and the like. A meshing co-rotating twin-screw extruder is generally widely used and can be preferably used. Also, a plurality of these extruders can be combined and used. There are no particular restrictions on the extruder and the extrusion temperature, but from the viewpoint of efficiently dispersing the resin composition, it is preferable to use a twin-screw extruder and perform melt-kneading at 260°C or higher. Depending on other production conditions, the screw rotation speed can be, for example, 150 to 350 rpm, and the extrusion amount can be 15 to 35 kg / hr.

[0057] The resin composition may contain, if necessary, heat stabilizers such as hindered phenol compounds, lactone compounds, phosphorus compounds, sulfur compounds, light stabilizers such as hindered amine compounds, benzotriazole compounds, lubricants, plasticizers, colorants, impact modifiers, hardness modifiers, antistatic agents, flame retardants, additives such as mineral oil, etc. These additives may be used alone or in combination of two or more. These additives can be added during the production of maleimide resin (A), polyamide resin (B), or resin (C), or during the melt-kneading of the ABS resin modifier or the resin composition. When the total resin composition is 100% by mass, these additives can be, for example, 5% by mass or less, 3% by mass, or 1% by mass. Also, the resin composition may not contain these additives.

[0058] The resin composition according to one embodiment of the present invention preferably has a melt mass flow rate of 5 to 15 g / 10 min. For example, it can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 g / 10 min, and may also be within the range between any two of the values exemplified here. Here, the melt mass flow rate can be measured at 240°C and a load of 98 N based on JIS K7210.

[0059] The resin composition according to one embodiment of the present invention preferably has a Vicat softening point of 100 to 105°C. For example, it can be 100, 101, 102, 103, 104, 105°C, and may also be within the range between any two of the values exemplified here. Here, the Vicat softening point can be measured using a test piece that has been conditioned for 16 hours in a thermostatic chamber at 23°C and a humidity of 50% with dimensions of 10 mm × 10 mm and a thickness of 4 mm, according to the 50 method (load 50 N, heating rate 50°C / hour) based on JIS K7206.

[0060] The resin composition according to one embodiment of the present invention preferably has a Charpy impact strength of 12 KJ / m 2 or more. The upper limit is not particularly limited, but for example, 30 KJ / m 2It can be achieved. The Charpy impact strength of the resin composition is, for example, 12, 15, 20, 25, 30 KJ / m 2 It can be achieved, and it may also be within the range between any two of the numerical values exemplified herein. Here, the Charpy impact strength can be measured using a notched test piece conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity based on JIS K7111-1, and adopting edgewise as the impact direction.

[0061] The resin composition according to one embodiment of the present invention preferably has a critical strain of 0.9% or more. Here, the critical strain can be measured by the method described in the examples.

[0062] The molded body according to one embodiment of the present invention can be obtained by molding the resin composition described above. The resin composition can be used to produce molded articles by known molding methods such as injection molding, sheet extrusion molding, vacuum molding, blow molding, foam molding, and profile extrusion molding. During molding, usually, the thermoplastic resin composition is heated to 200 to 300°C and then processed, but it is preferably 220 to 280°C. The molded articles can be used in automobiles, home appliances, OA equipment, building materials for housing, daily necessities, etc.

Examples

[0063] Hereinafter, the detailed content will be described using examples, but the present invention is not limited to the following examples.

[0064] <Production Example of Maleimide-based Resin (A-1)> 65 parts by mass of styrene, 7 parts by mass of maleic anhydride, 0.1 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged into an autoclave with a volume of about 25 liters equipped with a stirrer. After replacing the inside of the system with nitrogen gas, the temperature was raised to 92°C. A solution prepared by dissolving 28 parts by mass of maleic anhydride and 0.18 part by mass of t-butyl peroxy-2-ethylhexanoate in 100 parts by mass of methyl ethyl ketone was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butyl peroxy-2-ethylhexanoate was further added, the temperature was raised to 120°C, and the reaction was continued for 1 hour to obtain a styrene-maleic anhydride copolymer. Next, 31 parts by mass of aniline and 0.6 part by mass of triethylamine were added to the polymer solution, and the reaction was carried out at 140°C for 7 hours. The polymer solution after the imidization reaction was fed to a vent-type screw extruder to remove volatile components, and a pelletized maleimide-based resin (A-1) was obtained. The content of the residual maleimide-based monomer in the maleimide-based resin (A-1) was 220 ppm. The content of each constitutional unit measured using NMR was 52% by mass of styrene units, 46% by mass of N-phenylmaleimide units, and 2% by mass of maleic anhydride units. The weight-average molecular weight (Mw) was 150,000, and the midpoint glass transition temperature (Tmg) was 203°C.

[0065] <Production Example of Maleimide-based Resin (A-2)> Into an autoclave equipped with a stirrer and having a volume of about 25 liters, 42 parts by mass of styrene, 10 parts by mass of acrylonitrile, 4 parts by mass of maleic anhydride, 0.03 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 27 parts by mass of methyl ethyl ketone were charged. After replacing the inside with nitrogen gas, the temperature was raised to 92°C. A solution prepared by dissolving 21 parts by mass of maleic anhydride and 0.15 parts by mass of t-butyl peroxy-2-ethylhexanoate in 85 parts by mass of methyl ethyl ketone and 20 parts by mass of styrene were continuously added over 4.5 hours. Further, after the addition of maleic anhydride was completed, a solution prepared by dissolving 0.02 parts by mass of t-butyl peroxy-2-ethylhexanoate in 9 parts by mass of methyl ethyl ketone and 3 parts by mass of styrene were continuously added over 30 minutes. After the addition, the temperature was raised to 120°C and the reaction was carried out for 30 minutes to complete the polymerization. Then, 23 parts by mass of aniline and 0.4 parts by mass of triethylamine were added to the polymerization solution and reacted at 140°C for 7 hours. The polymer solution after the imidization reaction was fed to a vent-type screw extruder to remove volatile components, and a pelletized maleimide-based resin (A-2) was obtained. The content of each structural unit of A-2 measured by NMR was 52% by mass of styrene units, 8% by mass of acrylonitrile units, 39% by mass of N-phenylmaleimide units, and 1% by mass of maleic anhydride units. The weight average molecular weight (Mw) was 140,000, and the midpoint glass transition temperature (Tmg) was 176°C.

[0066] <Production Example of Maleimide-based Resin (A-3)> Into an autoclave with a volume of about 25 liters equipped with a stirrer, 65 parts by mass of styrene, 7 parts by mass of maleic anhydride, 0.2 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged. After replacing the inside of the system with nitrogen gas, the temperature was raised to 92°C. A solution prepared by dissolving 28 parts by mass of maleic anhydride and 0.18 parts by mass of t-butyl peroxy-2-ethylhexanoate in 100 parts by mass of methyl ethyl ketone was continuously added over 7 hours. After the addition, 0.03 parts by mass of t-butyl peroxy-2-ethylhexanoate was further added, and the temperature was raised to 120°C, followed by reacting for another 1 hour to obtain a styrene-maleic anhydride copolymer. Next, 21 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the polymer solution, and the mixture was reacted at 140°C for 7 hours. The polymer solution after the imidization reaction was fed into a vent-type screw extruder to remove volatile components, and a pelletized maleimide-based resin (A-3) was obtained. The residual maleimide-based monomer content in the maleimide-based resin (A-3) was 200 ppm. The content of each structural unit measured using NMR was 52% by mass of styrene units, 42% by mass of N-phenylmaleimide units, and 6% by mass of maleic anhydride units. The weight average molecular weight (Mw) was 120,000, and the midpoint glass transition temperature (Tmg) was 203°C.

[0067] <Polyamide resin (B-1)> As the polyamide resin (B-1), the following materials were used. Rilsan KNO manufactured by Arkema (terminal amino group amount: 3.2 mg KOH / g) <Polyamide resin (B-2)> As the polyamide resin (B-2), the following materials were used. Rilsan BESVO A MED manufactured by Arkema (terminal amino group amount: 2.5 mg KOH / g) <Polyamide resin (B-3)> As the polyamide resin (B-3), the following materials were used. Rilsan BMNO MED manufactured by Arkema (terminal amino group amount: 3.4 mg KOH / g) <Polyamide resin (B-4)> As the polyamide resin (B-4), the following materials were used. CM1017 manufactured by Toray Industries, Inc. (terminal amino group content: 3.4 mg KOH / g) <Polyamide resin (B-5)> As the polyamide resin (B-5), the following materials were used. CM1007 manufactured by Toray Industries, Inc. (terminal amino group content: 3.4 mg KOH / g) <Polyamide resin (B-6)> As the polyamide resin (B-6), the following materials were used. 1022B manufactured by Ube Industries, Ltd. (terminal amino group content: 2.7 mg KOH / g)

[0068] <Production example of ABS resin (C-1)> ABS resin (C-1) was produced by the emulsion graft polymerization method. In a reaction vessel equipped with a stirrer, 143 parts by mass of polybutadiene latex with an average particle diameter of 0.3 μm, 0.2 parts by mass of sodium formaldehyde sulfoxylate, 0.01 parts by mass of tetrasodium ethylenediaminetetraacetic acid, 0.005 parts by mass of ferrous sulfate, and 150 parts by mass of pure water were charged, and the temperature was heated to 50°C. Here, a monomer mixture of 75% by mass of styrene and 25% by mass of acrylonitrile: 50 parts by mass, 1.0 part by mass of t-dodecyl mercaptan, and 0.15 part by mass of cumene hydroperoxide were continuously added in portions over 4 hours. After the completion of the portionwise addition, the temperature was raised to 70°C, and the polymerization was further completed over 2 hours to obtain a latex of ABS resin (C-1). The obtained latex was coagulated using magnesium sulfate and sulfuric acid as a coagulant so that the pH of the slurry during coagulation was 6.8, washed, dehydrated, and dried to obtain powdery ABS resin (C-1). Regarding the obtained ABS resin (C-1), the polybutadiene content was 53% by mass based on the raw material formulation ratio during emulsion graft polymerization. The structural units excluding the rubbery polymer were measured by NMR, and styrene was 75% by mass and acrylonitrile was 25% by mass. The gel content was determined by the centrifugation method and was 72% by mass. Calculating the graft ratio from the gel content and the polybutadiene content, it was 44%. The toluene swelling degree was 8.1, and the number average particle diameter was calculated from the observation results of TEM and was 0.3 μm.

[0069] <Production Example of SAN Resin (C-2)> SAN resin (C-2) was produced by continuous bulk polymerization. One completely mixed tank-type stirred tank was used as the reactor, and polymerization was carried out with a capacity of 20 L. 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 6.5 L / h. Also, t-butyl peroxyisopropyl monocarbonate was continuously added to the supply line of the raw material solution at a concentration of 160 ppm as a polymerization initiator, and n-dodecyl mercaptan was continuously added at a concentration of 400 ppm as a chain transfer agent. The reaction temperature of the reactor was adjusted to 145°C. The polymer solution continuously taken out from the reactor was supplied to a vacuum devolatilization tank equipped with a preheater, and unreacted styrene, acrylonitrile, and ethylbenzene were separated. The temperature of the preheater was adjusted so that the polymer temperature in the devolatilization tank was 225°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 in a strand shape, cooled with cooling water, and cut to obtain pellet-shaped SAN resin (C-2). The constituent units were 74% by mass of styrene units and 26% by mass of acrylonitrile units. Also, the weight average molecular weight was 145,000.

[0070] <Examples and Comparative Examples> The maleimide resin (A) and polyamide resin (B) were melt-kneaded at 270 °C, 250 rpm, and 25 kg / hr using a twin-screw extruder TEM-35B manufactured by Toshiba Machine Co., Ltd. with the formulations shown in Table 1. The obtained strands were cut using a pelletizer to obtain an ABS resin modifier in the form of pellets approximately 2 mm in size. For the obtained ABS resin modifier, the particle diameter of the dispersed phase, tensile fracture elongation, flexural modulus, and Charpy impact strength were evaluated by the methods described below. The evaluation results are shown in Table 1. Also, the obtained ABS resin modifier, ABS resin, and SAN resin were melt-kneaded at 270 °C, 250 rpm, and 25 kg / hr using a twin-screw extruder TEM-35B manufactured by Toshiba Machine Co., Ltd. with the formulations shown in Table 2. The obtained strands were cut using a pelletizer to obtain a resin composition in the form of pellets approximately 2 mm in size. For the obtained resin composition, the melt mass flow rate, Vicat softening point, flexural modulus, Charpy impact strength, and chemical resistance were evaluated by the methods described below. The evaluation results are shown in Table 2.

[0071] <Reference Example> As Reference Example 1, without adding an ABS resin modifier containing a maleimide resin (A) and a polyamide resin (B), the ABS resin and SAN resin were separated according to the formulations shown in Table 2 and melt-kneaded at 270 °C, 250 rpm, and 25 kg / hr using a twin-screw extruder TEM-35B manufactured by Toshiba Machine Co., Ltd. The obtained strands were cut using a pelletizer to obtain a resin composition in the form of pellets approximately 2 mm in size. As Reference Example 2, without using an ABS resin modifier, the maleimide resin (A), polyamide resin (B), ABS resin, and SAN resin were separated according to the formulations shown in Table 2 and melt-kneaded at 270 °C, 250 rpm, and 25 kg / hr using a twin-screw extruder TEM-35B manufactured by Toshiba Machine Co., Ltd. The obtained strands were cut using a pelletizer to obtain a resin composition in the form of pellets approximately 2 mm in size.

[0072] (Average particle diameter of the dispersed phase) The cross-section image of the ABS resin modifier was observed with a transmission electron microscope H-7500 of Hitachi High-Tech Corporation, and the image analysis was carried out with the image analysis software Image-Pro Plus 6.3 of Hakuto Co., Ltd. The range of 5.7 μm in length and 8.5 μm in width was observed at a magnification of 6000 times, the area of each dispersed phase was measured, the diameter equivalent to a circle of each dispersed phase was defined as the equivalent circle diameter of each dispersed phase, and the number average value of the equivalent circle diameters of each dispersed phase was defined as the average particle diameter of the dispersed phase.

[0073] (Tensile fracture nominal strain) The tensile fracture nominal strain was measured at a tensile speed of 50 mm / min based on JIS K7161. The test specimens used were those conditioned in a constant temperature bath at 23°C and 50% humidity for 16 hours.

[0074] (Flexural modulus) The flexural modulus was measured at a flexural speed of 2 mm / min based on JIS K7171. The test specimens used were those conditioned in a constant temperature bath at 23°C and 50% humidity for 16 hours.

[0075] (Melt mass-flow rate) The melt mass-flow rate was measured at 240°C and a load of 98 N based on JIS K7210.

[0076] (Vicat softening temperature) The Vicat softening temperature was measured based on JIS K7206 using the 50 method (load 50 N, heating rate 50°C / hour). The test specimens were 10 mm × 10 mm and 4 mm thick. The test specimens used were those conditioned in a constant temperature bath at 23°C and 50% humidity for 16 hours. The measuring instrument used was an HDT&VSPT test apparatus manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0077] (Charpy impact strength) The Charpy impact strength was measured based on JIS K7111-1 using notched test specimens with the impact direction being edgewise. The test specimens used were those conditioned in a constant temperature bath at 23°C and 50% humidity for 16 hours. The measuring instrument used was a digital impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0078] (Chemical resistance) For a test piece with a shape of 316×20×2 mm, a major radius of 250 mm, and a minor radius of 150 mm, after 48 hours at 23°C, the cracks were observed by the 1 / 4 ellipse method, and the critical strain was calculated and evaluated according to the following formula. To eliminate the influence of molding strain, the test pieces were manufactured by pressing pellets at 260°C and then cutting them out. The chemical used was Magic Lin manufactured by Kao Corporation. ε = b / 2a 2 {1 - (a 2 - b 2 )X 2 / a 4} 1.5 × t × 100 (In the formula, ε represents the critical strain, a represents the major radius of the test piece, b represents the minor radius of the test piece, t represents the thickness of the test piece, and X represents the length from the end on the minor radius side of the test piece to the crack generation point.) Note that the smaller the value of the critical strain, the more likely it is that cracks will occur in the test piece under a small stress. In this application, those showing a value of 0.9 or more were considered qualified.

[0079]

Table 1

[0080]

Table 2

[0081] By using the ABS resin modifier of the example, a resin composition having an appropriate melt mass flow rate and Vicat softening point, and excellent impact resistance, chemical resistance, and rigidity can be obtained. On the other hand, the resin compositions using the ABS resin modifiers of the comparative examples and the reference example without the addition of the ABS resin modifier were inferior in one or more of the physical properties of impact resistance and chemical resistance.

Industrial Applicability

[0082] Since the resin composition using the ABS resin modifier of the present invention is excellent in the balance of heat resistance, mechanical strength, chemical resistance, and moldability, it can be suitably used particularly for parts having a complicated shape such as automobile interior materials.

Claims

1. An ABS resin modifier containing a maleimide resin (A) having maleimide monomer units, styrene monomer units, and unsaturated dicarboxylic anhydride monomer units, and a polyamide resin (B), wherein the amount of the maleimide monomer units contained in the maleimide resin (A) is 10 to 68% by mass when the entire maleimide resin (A) is 100% by mass, the amount of the styrene monomer units contained in the maleimide resin (A) is 30 to 70% by mass when the entire maleimide resin (A) is 100% by mass, the amount of the unsaturated dicarboxylic anhydride monomer units contained in the maleimide resin (A) is 1 to 10% by mass when the entire maleimide resin (A) is 100% by mass, the ABS resin modifier has a dispersed phase, the average particle diameter of the dispersed phase is 100 nm or less, and the dispersed phase contains a maleimide resin (A), the ABS resin modifier.

2. The ABS resin modifier according to claim 1, wherein the tensile fracture elongation measured at a tensile speed of 50 mm / min of a test piece conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity based on JIS K7161 is 10% or more.

3. The ABS resin modifier according to claim 1 or 2, wherein the content of the maleimide resin (A) in the ABS resin modifier is 40% by mass or less when the entire ABS resin modifier is 100% by mass.

4. A resin composition comprising the ABS resin modifier according to any one of claims 1 to 3 and a resin (C) containing an ABS resin.

5. The resin composition according to claim 4, wherein when the entire resin composition is 100% by mass, the polyamide resin (B) contained in the resin composition is less than 20% by mass.

6. The resin composition according to claim 4 or 5, wherein the Charpy impact strength measured using a notched test piece conditioned for 16 hours in a thermostatic chamber at 23°C and 50% humidity based on JIS K7111-1 and adopting edgewise as the impact direction is 12 kJ / m2 or more.

7. A method for producing a resin composition, comprising a step of melt-kneading a raw material containing the ABS resin modifier according to any one of claims 1 to 3 and a resin (C) containing an ABS resin in an extruder.

8. A molded article obtained by molding the resin composition according to any one of claims 4 to 6.

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