Masterbatch, method for producing the same, polycarbonate resin composition, injection foam molded article, and method for producing the same

Abstract

The present invention relates to a master batch that includes thermally expandable microcapsules (A) and a carrier resin composition (B), the carrier resin composition (B) being a carrier resin composition (B1) that includes an acrylic resin (C), an acrylic plasticizer (D1), and an oil-absorbent powder (E), or a carrier resin composition (B2) that includes the acrylic resin (C) and a low-molecular-weight styrene resin (D2), the acrylic plasticizer (D1) being 0.1-4 wt% and the oil-absorbent powder (E) being 0.1 to less than 4 wt% in the master batch in the case of the carrier resin composition (B1), and the low-molecular-weight styrene resin (D2) being 0.1 to less than 12 wt% in the master batch in the case of the carrier resin composition (B2).

Description

Technical Field

[0001] The present invention relates to a masterbatch containing thermally expandable microcapsules, a method for producing the same, a polycarbonate resin composition containing the same, a mixture, an injection foam molded article, and a method for producing the injection foam molded article.

Background Art

[0002] For injection foam molding of resins, thermally decomposable chemical foaming agents such as sodium bicarbonate are often used. In addition, thermally expandable microcapsules that expand and foam upon heating are also used for injection foam molding of resins. Thermally expandable microcapsules are usually used as a masterbatch containing 20 to 60% by weight of a chemical foaming agent or thermally expandable microcapsules in a thermoplastic resin or thermoplastic elastomer from the viewpoints of dispersibility in a base resin and workability. For example, Patent Document 1 describes a masterbatch containing thermally expandable microcapsules, a carrier resin containing an olefin polymer, and a lubricant. However, when a polycarbonate resin is foamed using the masterbatch of thermally expandable microcapsules described in Patent Document 1, since the carrier resin contains an olefin polymer, whitening due to incompatible components of the olefin polymer occurs on the surface of the injection foam molded article, resulting in a problem of poor appearance.

[0003] Therefore, in Patent Document 2, it is described that by using a masterbatch of thermally expandable microcapsules masterbatched using a carrier resin composition containing an acrylic resin having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C and a plasticizer having a weight average molecular weight of 1,000 or more and 20,000 or less and being liquid at 20°C, the occurrence of whitening is suppressed, and an injection foam molded article of a polycarbonate resin composition with good appearance can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, when producing the masterbatch described in Patent Document 2, depending on the type and blending amount of the plasticizer, the supplyability of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder is poor, and there is a problem that the discharge amount of the melt-kneaded product becomes low.

[0006] In order to solve the above-described conventional problems, the present invention provides a masterbatch having good supplyability of a carrier resin composition or a mixture of a thermally expandable microcapsule and a carrier resin composition to an extruder and an improved discharge amount of a melt-kneaded product, a method for producing the same, a polycarbonate resin composition containing the same, a mixture, an injection foam molded article, and a method for producing the injection foam molded article. [Means for Solving the Problems]

[0007] In one or more embodiments, the present invention relates to a masterbatch comprising a thermally expandable microcapsule (A) and a carrier resin composition (B), wherein the carrier resin composition (B) is a carrier resin composition (B1) or a carrier resin composition (B2). The carrier resin composition (B1) comprises an acrylic resin (C) having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C, an acrylic plasticizer (D1) having a weight average molecular weight of 1,000 or more and 20,000 or less and being liquid at 20°C, and an oil-absorbing powder (E). The carrier resin composition (B2) comprises an acrylic resin (C) having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C, and a low molecular weight styrene resin (D2) having a weight average molecular weight of 1,000 or more and 150,000 or less and being liquid or solid at 20°C. When the carrier resin composition (B) is the carrier resin composition (B1), in the masterbatch, the content of the acrylic plasticizer (D1) is 0.1% by weight or more and 4% by weight or less, and the content of the oil-absorbing powder (E) is 0.1% by weight or more and less than 4% by weight. When the carrier resin composition (B) is the carrier resin composition (B2), in the masterbatch, the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and less than 12% by weight. The present invention relates to a masterbatch characterized by the above.

[0008] In one or more embodiments, the present invention also relates to a method for producing the masterbatch, which includes a step of mixing a thermally expandable microcapsule (A) and a carrier resin composition (B), a step of supplying the obtained mixture to an extruder and melt-kneading it, and a step of extruding the obtained melt-kneaded product. The present invention relates to a method for producing a masterbatch.

[0009] In one or more embodiments, the present invention also relates to a method for producing the masterbatch, which includes a step of supplying a thermally expandable microcapsule (A) and a carrier resin composition (B) to an extruder respectively, a step of melt-kneading the thermally expandable microcapsule (A) and the carrier resin composition (B), and a step of extruding the obtained melt-kneaded product. The present invention relates to a method for producing a masterbatch.

[0010] The present invention also relates to, in one or more embodiments, a mixture containing thermally expandable microcapsules (A) and a carrier resin composition (B), wherein the thermally expandable microcapsules (A) and the carrier resin composition (B) are the thermally expandable microcapsules (A) and the carrier resin composition (B) respectively. When the carrier resin composition (B) is the carrier resin composition (B1), the mixture is a mixture of powder and liquid. When the carrier resin composition (B) is the carrier resin composition (B2), the mixture is a mixture of powder and liquid or a powder mixture. The present invention relates to a mixture characterized in that when the mixture is fed into a twin-screw type metering feeder, the mixture flows in the feeder by the rotation of the twin-screw and is discharged from the feeder.

[0011] The present invention also relates to, in one or more embodiments, the masterbatch and a polycarbonate resin composition containing a polycarbonate resin.

[0012] The present invention also relates to, in one or more embodiments, an injection foam molded article characterized by injection foam molding the polycarbonate resin composition.

[0013] The present invention also relates to, in one or more embodiments, a method for manufacturing an injection foam molded article by injection foam molding the polycarbonate resin composition.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a masterbatch with good supplyability of the carrier resin composition or a mixture of thermally expandable microcapsules and the carrier resin composition to an extruder, an improved discharge amount of the melt-kneaded product, a polycarbonate resin composition containing the same, an injection foam molded article using the polycarbonate resin composition, and a manufacturing method thereof. Further, according to the manufacturing method of the present invention, it is easy to supply the carrier resin composition or a mixture of thermally expandable microcapsules and the carrier resin composition to an extruder, the discharge amount of the melt-kneaded product becomes high, and the productivity of the masterbatch becomes good.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0016] In order to solve the above problems, the inventors of the present invention have made intensive studies. As a result, an acrylic resin (C) having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C, an acrylic plasticizer (D1) having a weight average molecular weight of 1,000 or more and 20,000 or less and being liquid at 20°C, and an oil-absorbing powder (E) are used. In a masterbatch containing the thermally expandable microcapsules (A) and the carrier resin composition (B1), the content of the acrylic plasticizer (D1) is made 0.1% by weight or more and 4% by weight or less, and the content of the oil-absorbing powder (E) is made 0.1% by weight or more and less than 4% by weight. Thus, it has been found that the supplyability of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder and the discharge amount of the melt-kneaded product of the thermally expandable microcapsules and the carrier resin composition can be improved. In a masterbatch containing the thermally expandable microcapsules (A), the acrylic resin (C) and the acrylic plasticizer (D1), while the content of the acrylic plasticizer (D1) is made 0.1% by weight or more and 4% by weight or less, the oil-absorbing powder (E) is used in combination at 0.1% by weight or more and less than 4% by weight. As a result, the adhesiveness of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition is reduced and the fluidity is improved. Therefore, it is presumed that the supplyability of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder and the discharge amount of the melt-kneaded product of the thermally expandable microcapsules and the carrier resin composition are improved. Alternatively, the inventors of the present invention used a carrier resin composition (B2) containing an acrylic resin (C) having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C, and a low molecular weight styrene resin (D2) having a weight average molecular weight of 1,000 or more and 150,000 or less and being liquid or solid at 20°C. In a masterbatch containing thermally expandable microcapsules (A) and the carrier resin composition (B2), by setting the content of the low molecular weight styrene resin (D2) to be 0.1% by weight or more and less than 12% by weight, it was found that the supplyability of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder and the discharge amount of the melt-kneaded product of the thermally expandable microcapsules and the carrier resin composition can be improved. By using a predetermined amount of a low molecular weight styrene resin (D2) that has a shear force reduction effect during kneading and does not reduce the fluidity of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition, it is presumed that the supplyability of the carrier resin composition or the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder and the discharge amount of the melt-kneaded product of the thermally expandable microcapsules and the carrier resin composition are improved.

[0017] Hereinafter, embodiments of the present invention will be specifically described. Note that the present invention is not limited to the embodiments described below.

[0018] <Thermally expandable microcapsules (A)> The thermally expandable microcapsules (A) are capsule-shaped foaming agents in which a liquid low-boiling compound is encapsulated with a shell of a thermoplastic polymer. The expanded capsules function as a foaming agent due to the pressure of the low-boiling compound vaporized by heating in the cylinder of an injection molding machine. As the thermally expandable microcapsules (A), for example, those described in JP-A-2011-16884 may be preferably used. Specifically, the thermally expandable microcapsules (A) have a core-shell structure, the core is composed of one or more compounds having a boiling point of 10°C or more and 330°C or less, the shell encapsulates the core, and is composed of a thermoplastic resin.

[0019] The core may be composed of one or more compounds selected from among compounds having a boiling point of 10°C or higher and 330°C or lower. The compounds constituting the core are not particularly limited, and examples thereof include hydrocarbons, alcohols, ketones, and the like. The hydrocarbons are not particularly limited, and examples thereof include pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, and structural isomers of these hydrocarbons. The compound constituting the core is preferably one or more hydrocarbons having a boiling point of 10°C or higher and 330°C or lower, more preferably one or more hydrocarbons having a boiling point of 30°C or higher and 280°C or lower, and still more preferably one or more hydrocarbons having a boiling point of 30°C or higher and 200°C or lower. By using a compound having a boiling point of 10°C or higher, it is easy to prepare a masterbatch of the thermally expandable microcapsules (A). Further, by using a compound having a boiling point of 330°C or lower, the dispersibility during polymerization becomes good, and it is easy to produce thermally expandable microcapsules.

[0020] As the monomer component of the thermoplastic resin constituting the shell of the thermally expandable microcapsules (A), for example, nitrile monomers, (meth)acrylate monomers, aromatic vinyl monomers, vinyl monomers having a carboxyl group, diene monomers, and monomers having one or more reactive functional groups selected from the group consisting of methylol groups, hydroxyl groups, amino groups, epoxy groups, and isocyanate groups can be used.

[0021] From the viewpoint of suppressing the decomposition of the main chain of the resin component such as a polycarbonate resin by the shell of the thermally expandable microcapsules (A), the thermoplastic resin constituting the shell preferably contains one or more selected from the group consisting of the above-described nitrile monomers, (meth)acrylate monomers, aromatic vinyl monomers, and vinyl monomers having a carboxyl group. Further, the thermoplastic resin constituting the shell may appropriately contain a chain transfer agent and a monomer having a reactive functional group.

[0022] Examples of the nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile, and the like.

[0023] Examples of the (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and the like. In the present invention, “(meth)acrylate” may be methacrylate or acrylate.

[0024] Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, p-nitrostyrene, chloromethylstyrene, and the like.

[0025] Examples of the vinyl monomer having a carboxyl group include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, cinnamic acid; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid, citraconic acid, chloromaleic acid, and anhydrides thereof; and mono-esters of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, and the like.

[0026] Examples of the diene monomer include butadiene, isoprene, chloroprene, and the like.

[0027] Examples of the monomer having at least one reactive functional group selected from the group consisting of a hydroxymethyl group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group (hereinafter sometimes simply referred to as "monomer having a reactive functional group") include N-methylol(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, vinyl glycidyl ether, propenyl glycidyl ether, glycidyl (meth)acrylate, glycerin mono(meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, p-hydroxystyrene, blocked isocyanate, and the like. Examples of the blocked isocyanate include blocked isocyanates of isocyanate compounds (such as diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, and tolylene diisocyanate) with phenol, alcohol, dimethyl malonate, diethyl malonate, ethyl acetoacetate, oxime, dimethylpyrazole, methyl ethyl ketone oxime, caprolactam, and the like. In the present invention, "(meth)acrylamide" may be methacrylamide or acrylamide.

[0028] The chain transfer agent may be any one that is used in ordinary radical polymerization and is not particularly limited. Specifically, a mercaptan-based compound can be used. Examples of the mercaptan-based compound that can be preferably used include alkyl mercaptans such as n-dodecyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan, and n-octadecyl mercaptan, 2-mercaptobenzothiazole, bromotrichloromethane, α-methylstyrene dimer, 2-ethylhexyl thioglycolate, and the like.

[0029] From the viewpoint of not causing decomposition of resin components such as polycarbonate resins and improving the surface properties of injection foam moldings, in the thermoplastic resin constituting the shell, the concentration of structural units derived from one or more monomers selected from the group consisting of monomers containing a carboxyl group and monomers containing an amino group is preferably 12 mmol / g or less, more preferably 10 mmol / g or less, still more preferably 8 mmol / g or less, even more preferably 5 mmol / g or less, even more preferably 3 mmol / g or less, particularly preferably 1 mmol / g or less, and most preferably substantially free of monomers containing a carboxyl group and / or monomers containing an amino group. The lower limit of the concentration of carboxyl groups in the thermoplastic resin constituting the shell may be 0.001 mmol / g or more.

[0030] From the viewpoint of suppressing the decomposition of the main chain of resins such as polycarbonate resins, in the thermally expandable microcapsules (A), the concentration of the alkaline substance is preferably 2000 ppm or less, more preferably 1000 ppm or less, and still more preferably 800 ppm or less. If it exceeds 2000 ppm, the molecular weight of the polycarbonate resin may decrease, and the strength of the molded body may decrease. Examples of the alkaline substance include ionic components derived from hydroxides (salts) of alkali metals and / or alkaline earth metals, and specifically include ionic components derived from hydroxides (salts) of metals such as Li, Na, Mg, K, Ca, and Ba.

[0031] The pH of the thermally expandable microcapsules (A) is preferably near neutrality. The thermally expandable microcapsules (A) can generally be produced by allowing suspension polymerization to proceed in an aqueous dispersion medium with a mixture containing a polymerizable monomer and a low-boiling compound that forms a core, thereby encapsulating the low-boiling compound as a core component within a shell of a thermoplastic resin composed of the monomer. The pH of the thermally expandable microcapsules (A) is preferably adjusted during such polymerization, and generally, a method of adding a potassium hydrogen phosphate buffer solution can be mentioned. The preferable range of pH is 6.0 or more and 8.0 or less, a more preferable range is 6.0 or more and 7.5 or less, and an even more preferable range is 6.0 or more and 7.0 or less. The method for measuring pH includes the glass electrode method. In the glass electrode method, two electrodes, a glass electrode and a reference electrode, are used to detect the potential difference generated between the electrodes and convert it into a pH value.

[0032] From the viewpoint of not causing a decrease in the molecular weight of the polycarbonate resin, in the thermally expandable microcapsules (A), the thermoplastic resin constituting the shell preferably satisfies the following conditions. The temperature at which 5% weight loss occurs as measured by TG / DTA of the pellets obtained by kneading 95 parts by weight of the polycarbonate resin and 5 parts by weight of the thermoplastic resin constituting the shell at 300 °C in a φ30 mm single-screw extruder is preferably 200 °C or higher, more preferably 220 °C or higher, even more preferably 240 °C or higher, and particularly preferably 260 °C or higher. Also, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the pellets, with respect to the Mw and Mn of the polycarbonate resin, the preferable range of the retention rate of Mw and Mn is each 60% or more, a more preferable range is 80% or more, an even more preferable range is 90% or more, and a particularly preferable range is 95% or more.

[0033] The thermally expandable microcapsules (A) preferably have an average particle diameter (when not expanded) of 0.5 μm or more and 50 μm or less, more preferably 0.7 μm or more and 50 μm or less, still more preferably 1.0 μm or more and 45 μm or less, even more preferably 1.0 μm or more and 40 μm or less, and particularly preferably 1.0 μm or more and 35 μm or less. The maximum particle diameter of the thermally expandable microcapsules (A) during heating is in the range of about 3 to 5 times the average particle diameter when not expanded. If the average particle diameter when not expanded is 0.5 μm or more and 50 μm or less, the particle diameter during expansion will be in the range of about 1.5 μm or more and 250 μm or less, and a large reduction in the Charpy impact strength and surface impact strength during foaming can be greatly suppressed. The average particle diameter of the thermally expandable microcapsules (A) when not expanded can be measured using a particle size distribution measuring device, specifically, the particle size distribution measuring device SALD-3000J manufactured by Shimadzu Corporation.

[0034] The thermally expandable microcapsules (A) preferably have a maximum expansion temperature (also referred to as the maximum foaming temperature) of 180°C or more and 300°C or less, more preferably 190°C or more and 290°C or less, still more preferably 200°C or more and 280°C or less, and particularly preferably 210°C or more and 270°C or less. In the present invention, the maximum expansion temperature of the thermally expandable microcapsules (A) can be measured by the measuring method described in Patent No. 5484673. Specifically, "TMA measurement" is performed using a TMA-7 type manufactured by PerkinElmer. Approximately 0.25 mg of the sample is placed in a container, the temperature is raised at a rate of 5°C / min, the displacement of its height is continuously measured, and the temperature at which the displacement of the height of the sample in the container becomes maximum is taken as the maximum expansion temperature. When the maximum expansion temperature of the thermally expandable microcapsules (A) is within the above-described range, since it matches the molding temperature of the polycarbonate-based resin, a low-density and high-strength injection foam molded article can be easily obtained.

[0035] <Carrier resin composition (B1)> The carrier resin composition (B1) contains an acrylic resin (C) having a weight average molecular weight of 8,000 or more and 350,000 or less and being solid at 20°C, an acrylic plasticizer (D1) having a weight average molecular weight of 1,000 or more and 20,000 or less and being liquid at 20°C, and an oil-absorbing powder (E). In the masterbatch containing the thermally expandable microcapsules (A) and the carrier resin composition (B1), the content of the acrylic plasticizer (D1) is 0.1% by weight or more and 4% by weight or less, and the content of the oil-absorbing powder (E) is 0.1% by weight or more and less than 4% by weight. Thereby, the supplyability of the carrier resin composition (B1), particularly the mixture of the thermally expandable microcapsules (A) and the carrier resin composition (B1) to the extruder, and the discharge amount of the melt-kneaded product of the thermally expandable microcapsules and the carrier resin composition are improved.

[0036] ≪Acrylic resin (C)≫ The acrylic resin (C) has a weight-average molecular weight of 8,000 or more and 350,000 or less, preferably 10,000 or more and 330,000 or less, more preferably 10,000 or more and 300,000 or less, still more preferably 10,000 or more and 280,000 or less, even more preferably 14,000 or more and 330,000 or less, even more preferably 14,000 or more and 300,000 or less, even more preferably 14,000 or more and 280,000 or less, even more preferably 14,000 or more and 200,000 or less, and particularly preferably 14,000 or more and 100,000 or less. Alternatively, the weight-average molecular weight of the acrylic resin (C) is preferably 16,000 or more and 330,000 or less, more preferably 16,000 or more and 300,000 or less, even more preferably 16,000 or more and 280,000 or less, even more preferably 16,000 or more and 200,000 or less, and particularly preferably 16,000 or more and 100,000 or less. Alternatively, the weight-average molecular weight of the acrylic resin (C) is preferably 19,000 or more and 330,000 or less, more preferably 19,000 or more and 300,000 or less, even more preferably 19,000 or more and 280,000 or less, even more preferably 19,000 or more and 200,000 or less, and particularly preferably 19,000 or more and 100,000 or less. In the present invention, the weight-average molecular weight and number-average molecular weight of the resin are measured by GPC (gel permeation chromatography).

[0037] The acrylic resin (C) is solid at 20°C. It has excellent handleability and good processability of the masterbatch. From the viewpoint of handleability, the acrylic resin (C) is preferably solid at 20°C or more and 25°C or less (room temperature).

[0038] From the viewpoint of the processability of the masterbatch, the acrylic resin (C) preferably has a glass transition temperature of 20°C or more and 150°C or less, more preferably 25°C or more and 140°C or less, and still more preferably 25°C or more and 130°C or less.

[0039] The acrylic resin (C) is not particularly limited. However, from the perspective of compatibility with a polycarbonate resin, for example, it is more preferably an acrylic resin containing acrylic resin particles (a) having an average particle diameter of 50 μm or more and 500 μm or less, and acrylic resin particles (b) having an average particle diameter of 0.05 μm or more and 0.5 μm or less that coat the acrylic resin particles (a).

[0040] The acrylic resin particles (a) desirably have an average particle diameter of 50 μm or more and 500 μm or less, preferably 75 μm or more and 300 μm or less, and more preferably 100 μm or more and 250 μm or less. The acrylic resin particles (a) having the above-described average particle diameter can be obtained by the suspension polymerization method. If the average particle diameter of the acrylic resin particles (a) is 50 μm or more, the filterability is improved, and if it is 500 μm or less, when a particulate compounding agent is powder-mixed with the acrylic resin (C), it can be uniformly mixed. The average particle diameter of the acrylic resin particles (a) is measured using Microtrac MT3300 manufactured by Microtrac BEL Corporation.

[0041] In the acrylic resin (C), the fact that the acrylic resin particles (b) coat the acrylic resin particles (a) means that all of the surface of the acrylic resin particles (a) may be coated with the acrylic resin particles (b), or the surface of the acrylic resin particles (a) may be partially coated with the acrylic resin particles (b). Preferably, 50% or more of the surface area of the acrylic resin particles (a) is coated with the acrylic resin particles (b), and more preferably 60% or more is coated. When the coated surface area is 50% or more, the powder properties of the acrylic resin (C) are improved.

[0042] By coating acrylic resin particles (a) with acrylic resin particles (b), the average particle diameter of the acrylic resin particles (a) preferably increases by 3% or more and 50% or less compared to that before coating. If the change in the acrylic resin particles (a) is less than 3%, the acrylic resin particles (a) tend to remain in the system, and as a result, the filterability is less likely to be improved. That is, the average particle diameter of the acrylic resin (C) is preferably 3% or more and 50% or less larger than the average particle diameter of the acrylic resin particles (a). The average particle diameter of the acrylic resin (C) is measured using Microtrac MT3300 manufactured by Microtrac Bell Co., Ltd.

[0043] From the viewpoint of easily controlling the dust accompanying the polymer obtained by suspension polymerization, the acrylic resin particles (a) are preferably composed of 30% by weight or more and 100% by weight or less of (meth)acrylic acid ester and 0% by weight or more and 70% by weight or less of a vinyl monomer copolymerizable therewith. More preferably, it is composed of 70% by weight or more and 100% by weight or less of (meth)acrylic acid ester and 0% by weight or more and 30% by weight or less of a vinyl monomer copolymerizable therewith. In the acrylic resin particles (a), when the content of the structural unit derived from (meth)acrylic acid ester is 30% by weight or more, the compatibility with the acrylic resin particles (b) is good and the molding process becomes good. In the present invention, "(meth)acrylic acid" may be methacrylic acid or acrylic acid.

[0044] (Meth)acrylic esters are not particularly limited, and examples thereof include alkyl acrylates having an alkyl group with 10 or fewer carbon atoms such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., and alkyl methacrylates having an alkyl group with 10 or fewer carbon atoms such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. These may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining a molded article of good quality in combination with the acrylic resin particles (b), the (meth)acrylic ester is preferably at least one selected from the group consisting of methyl methacrylate, butyl methacrylate, ethyl acrylate, and butyl acrylate.

[0045] In addition, the vinyl monomer copolymerizable with the (meth)acrylic ester is not particularly limited, and examples thereof include aromatic vinyl monomers such as styrene, α-methylstyrene, monochlorostyrene, dichlorostyrene, etc.; vinyl carboxylic acid monomers such as acrylic acid, methacrylic acid, etc.; vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, etc.; vinyl halide monomers such as vinyl chloride, vinyl bromide, chloroprene, etc.; alkenes such as vinyl acetate, ethylene, propylene, butylene, butadiene, isobutylene, etc.; halogenated alkenes; polyfunctional monomers such as allyl methacrylate, diallyl phthalate, triallyl cyanurate, monoethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, glycidyl methacrylate, etc. These may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining a molded article of good quality in combination with the acrylic resin particles (b), the copolymerizable vinyl monomer is preferably at least one selected from the group consisting of styrene, α-methylstyrene, acrylic acid, methacrylic acid, acrylonitrile, vinyl acetate, allyl methacrylate, and glycidyl methacrylate.

[0046] The acrylic resin particles (a) can be polymer particles obtained by suspension polymerization of one or more of the above-described monomers, and in some cases, can be homopolymer or graft copolymer particles of the polymer obtained by copolymerization or graft polymerization.

[0047] As the dispersion stabilizer in suspension polymerization, for example, ordinary inorganic dispersants and organic dispersants can be used. Examples of inorganic dispersants include magnesium carbonate, tricalcium phosphate, etc. Examples of organic dispersants include natural polymer dispersants and synthetic polymer dispersants such as starch, gelatin, acrylamide, partially saponified polyvinyl alcohol (PVA), partially saponified polymethyl methacrylate, polyacrylic acid, salts of polyacrylic acid, cellulose, methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polyalkylene oxide, polyvinyl pyrrolidone, polyvinyl imidazole, sulfonated polystyrene, etc., and low molecular weight dispersants (also referred to as emulsifiers) such as alkylbenzene sulfonates, fatty acid salts, etc. From the viewpoint of suppressing the decomposition of the polycarbonate resin, PVA or polyalkylene oxide such as polyethylene oxide is preferred.

[0048] As the polymerization initiator in suspension polymerization, peroxides such as benzoyl peroxide, lauroyl peroxide, etc., and azo compounds such as azobisisobutyronitrile, etc. can be mentioned.

[0049] Also, for molecular weight adjustment, a chain transfer agent may be used. Examples of chain transfer agents include alkyl mercaptans having 2 to 18 carbon atoms; mercapto acids such as thioglycolic acid ester, β-mercaptopropionic acid, etc.; aromatic mercaptans such as benzyl mercaptan, thiophenol, thiocresol, thionaphthol, etc. Examples of alkyl mercaptans having 2 to 18 carbon atoms include n-dodecyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan, n-octadecyl mercaptan, etc. Among these, alkyl mercaptans having 4 to 12 carbon atoms are preferred. Examples of thioglycolic acid ester include 2-ethylhexyl thioglycolate, etc.

[0050] The addition amounts of the dispersion stabilizer, polymerization initiator, and chain transfer agent can be appropriately set according to the monomers used and the physical properties of the target suspension polymer particles (acrylic resin particles (a)).

[0051] The method for producing the suspension polymer particles is not particularly limited, and all generally usable methods can be employed. For example, a method in which a monomer or monomer mixture is suspended in water and the polymerization reaction is carried out as it is; a method in which a part of the monomer or monomer mixture is suspended in water to initiate the polymerization reaction, and as the polymerization reaction proceeds, the aqueous suspension of the remaining monomer or monomer mixture is added to the polymerization reaction tank in one or several steps or continuously to carry out the polymerization reaction; a method in which a part of the monomer or monomer mixture is suspended in water to initiate the polymerization reaction, and as the polymerization reaction proceeds, the remaining monomer or monomer mixture is added to the polymerization reaction tank in one or several steps or continuously to carry out the polymerization reaction, etc. can be mentioned.

[0052] There are no particular restrictions on the method for adding the polymerization initiator and the chain transfer agent, but a method in which both the polymerization initiator and the chain transfer agent are dissolved in the monomer and then the monomer is suspended in water and the polymerization reaction is carried out as it is is preferred. The time required for polymerization varies depending on the type and amount of the polymerization initiator, the polymerization temperature, etc., but is usually 1 hour or more and 24 hours or less. Also, it is possible to add additives usually added during the molding process of plastics, such as plasticizers, lubricants, stabilizers, and ultraviolet absorbers, to the monomer during suspension polymerization.

[0053] The acrylic resin particles (b) may have an average particle diameter of 0.05 μm or more and 0.5 μm or less, but preferably 0.06 μm or more and 0.3 μm or less. The acrylic resin particles (b) having the above-described average particle diameter can be obtained by an emulsion polymerization method. When the average particle diameter of the acrylic resin particles (b) is within the above-described range, the processability when molding the acrylic resin (C), as well as the impact resistance and transparency of the resulting molded article, tend to be good. The average particle diameter of the acrylic resin particles (b) is measured using Microtrac MT3300 manufactured by Microtrac Bell Co., Ltd.

[0054] The acrylic resin particles (b) are preferably composed of 30 to 100% by weight of (meth)acrylate and 0 to 70% by weight of a vinyl monomer copolymerizable therewith, and more preferably composed of 50 to 100% by weight of (meth)acrylate, 0 to 40% by weight of an aromatic vinyl monomer, 0 to 10% by weight of a vinyl monomer copolymerizable therewith, and 0 to 5% by weight of a polyfunctional monomer. 50 to 90 parts by weight of latex particles (b1) and 10 to 50 parts by weight of polymer particles obtained by polymerizing a monomer mixture (b2) containing 10 to 100% by weight of (meth)acrylate, 0 to 90% by weight of an aromatic vinyl monomer, 0 to 25% by weight of a vinyl cyanide monomer, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith, with the total of the latex particles (b1) and the monomer mixture (b2) being 100 parts by weight. In this specification, the range indicated by "… to …" is the same as the range indicated by "… or more and … or less".

[0055] The (meth)acrylate constituting the acrylic resin particles (b) is not particularly limited, and for example, the (meth)acrylates listed when describing the acrylic resin particles (a) can be appropriately used. Also, the aromatic vinyl monomer, vinyl cyanide monomer, polyfunctional monomer, and other copolymerizable vinyl monomers constituting the acrylic resin particles (b) are not particularly limited, and for example, those listed when describing the acrylic resin particles (a) can be appropriately used.

[0056] The acrylic resin particles (b) are more preferably latex particles (b1) obtained by emulsion polymerization of a monomer mixture (a) containing 50 to 95% by weight of methyl methacrylate, 5 to 50% by weight of a methacrylic acid ester having an alkyl group having 2 to 8 carbon atoms, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith, 70 to 95 parts by weight, and 5 to 30 parts by weight of emulsion polymerized particles obtained by graft polymerization of a monomer mixture (b2) containing 20 to 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters excluding acrylic acid esters and methyl methacrylate, 20 to 80% by weight of methyl methacrylate, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith, and the total of the latex particles (b1) and the monomer mixture (b2) is 100 parts by weight. Specifically, 70 to 95 parts by weight of a monomer mixture (I) containing 50 to 95% by weight of methyl methacrylate, 5 to 50% by weight of a methacrylic acid ester having an alkyl group having 2 to 8 carbon atoms, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith is emulsion polymerized, and in the presence of the resulting polymer latex, 20 to 80% by weight of one or more monomers selected from the group consisting of methacrylic acid esters excluding acrylic acid esters and methyl methacrylate, 20 to 80% by weight of methyl methacrylate, and 0 to 20% by weight of a vinyl monomer copolymerizable therewith are graft polymerized. It is preferably an emulsion polymerized particle obtained by graft polymerizing 5 to 30 parts by weight of a monomer mixture (II), and the total of the monomer mixture (I) and the monomer mixture (II) is 100 parts by weight.

[0057] The acrylic resin particles (b) are more preferably 10 to 60 parts by weight of a first-stage polymer obtained by polymerizing a monomer mixture (III) containing 40 to 99.99% by weight of methyl methacrylate, 0 to 59.99% by weight of a vinyl monomer copolymerizable therewith, and 0.01 to 10% by weight of a polyfunctional monomer, and 40 to 90 parts by weight of a second-stage polymer particle (latex particle (b1)) obtained by polymerizing a monomer mixture (IV) containing 60 to 99.9% by weight of an alkyl acrylate, 0 to 39.9% by weight of a vinyl monomer copolymerizable therewith, and 0.1 to 5% by weight of a polyfunctional monomer, the total of the monomer mixture (III) and the monomer mixture (IV) being 100 parts by weight, and are emulsion polymerized particles obtained by polymerizing 11 to 67 parts by weight of a monomer mixture containing 60 to 100% by weight of a (meth)acrylate ester and 0 to 40% by weight of a vinyl monomer copolymerizable therewith. Specifically, 10 to 60 parts by weight of a monomer mixture (III) containing 40 to 99.99% by weight of methyl methacrylate, 0 to 59.99% by weight of a vinyl monomer copolymerizable therewith, and 0.01 to 10% by weight of a polyfunctional monomer is emulsion polymerized, and in the presence of the latex of the obtained first-stage polymer, 40 to 90 parts by weight of a monomer mixture (IV) containing 60 to 99.9% by weight of an alkyl acrylate, 0 to 39.9% by weight of a vinyl monomer copolymerizable therewith, and 0.1 to 5% by weight of a polyfunctional monomer is emulsion polymerized to obtain a second-stage polymer latex, the total of the monomer mixture (III) and the monomer mixture (IV) being 100 parts by weight, and in the presence of 100 parts by weight of the solid content (latex particle (b1)) of the obtained second-stage polymer latex, 11 to 67 parts by weight of a monomer mixture (b2) containing 60 to 100% by weight of a (meth)acrylate ester and 0 to 40% by weight of a vinyl monomer copolymerizable therewith is further polymerized to obtain emulsion polymerized particles having a three-layer structure.

[0058] The latex particles (b1) preferably have a glass transition temperature of 0°C or lower, more preferably -30°C or lower. When the glass transition temperature of the latex particles (b1) is 0°C or lower, the impact resistance of the injection foam molded article is likely to be improved.

[0059] The acrylic resin (C) preferably contains 22 to 100 parts by weight, more preferably 25 to 100 parts by weight, and even more preferably 30 to 100 parts by weight of the acrylic resin particles (b) with respect to 100 parts by weight of the acrylic resin particles (a). If the amount of the acrylic resin particles (b) is less than 22 parts by weight with respect to 100 parts by weight of the acrylic resin particles (a), the filterability may not be improved. Further, when the amount of the acrylic resin particles (b) exceeds 100 parts by weight with respect to 100 parts by weight of the acrylic resin particles (a), the water content after dehydration of the acrylic resin (C) may increase.

[0060] The acrylic resin (C) is not particularly limited, but can be produced, for example, as follows. First, a suspension containing acrylic resin particles (a) is prepared by suspension polymerization, and an emulsion polymerization latex containing acrylic polymer particles (b) is prepared by emulsion polymerization. Next, the suspension and the emulsion polymerization latex are mixed. Next, the solid content concentration (total concentration of the acrylic polymer particles (a) and the acrylic polymer particles (b)) in the obtained mixed suspension is adjusted to 25% by weight or more and 35% by weight or less. Next, an aqueous electrolyte solution is added to the mixed suspension having the adjusted solid content concentration at a temperature not higher than the Vicat softening temperature of the acrylic polymer particles (b), and the mixture is heated to a temperature higher than the Vicat softening temperature of the acrylic polymer particles (b), and then the acrylic resin (C) is recovered by solid-liquid separation. By the above-described production method, the surface of the acrylic polymer particles (a) can be uniformly coated with the acrylic polymer particles (b), and the remaining amount of the acrylic polymer particles (b) that causes deterioration of the filterability can be significantly reduced.

[0061] The method of mixing the suspension containing the acrylic resin particles (a) obtained by suspension polymerization and the emulsion polymerization latex containing the acrylic polymer particles (b) obtained by emulsion polymerization is preferably adding the emulsion polymerization latex to the suspension or adding the suspension to the emulsion polymerization latex under stirring.

[0062] The solid content ratio of the suspension containing acrylic resin particles (a) and the emulsion polymerization latex containing acrylic polymer particles (b) is preferably 22 parts by weight or more and 100 parts by weight or less, more preferably 25 parts by weight or more and 100 parts by weight or less, and even more preferably 30 parts by weight or more and 100 parts by weight or less, based on 100 parts by weight of the acrylic resin particles (a). When the amount of the acrylic polymer particles (b) is 22 parts by weight or more based on 100 parts by weight of the acrylic resin particles (a), the residual acrylic resin particles (b) in the system are reduced, and as a result, the filterability is easily improved. Also, when the amount of the acrylic polymer particles (b) is 100 parts by weight or less based on 100 parts by weight of the acrylic resin particles (a), the water content after dehydration of the obtained acrylic resin (C) becomes low.

[0063] When mixing the suspension and the emulsion polymerization latex, there are no particular restrictions on the solid content concentrations of the suspension and the emulsion polymerization latex, and it is most convenient and preferable in terms of production to directly use the emulsion polymerization latex or the suspension polymerization suspension obtained by a normal polymerization operation. Usually, the solid content concentration (concentration of the acrylic resin particles (a)) of the suspension containing the acrylic resin particles (a) is preferably 25% by weight or more and 55% by weight or less, more preferably 30% by weight or more and 45% by weight or less, even more preferably 33% by weight or more and 45% by weight or less, and particularly preferably 35% by weight or more and 40% by weight or less. The solid content concentration (concentration of the acrylic resin particles (b)) of the emulsion polymerization latex containing the acrylic resin particles (b) is preferably 25% by weight or more and 55% by weight or less, more preferably 25% by weight or more and 45% by weight or less, even more preferably 30% by weight or more and 45% by weight or less, and particularly preferably 30% by weight or more and 40% by weight or less. The temperature during mixing is preferably 5°C or higher. When it is lower than 5°C, the utility consumption of the subsequent heat treatment operation tends to be large, which is not preferable.

[0064] When adding the aqueous electrolyte solution, the solid content concentration (concentration of polymer particles) in the mixed suspension is preferably 25% by weight or more and 35% by weight or less, more preferably 27% by weight or more and 33% by weight or less. When the concentration of polymer particles (solid content) in the mixed suspension when adding the aqueous electrolyte solution is 25% by weight or more, the generation of fine aggregates with a particle size of 50 μm or less in the mixed suspension after adding the aqueous electrolyte solution and performing heat treatment is suppressed, the filterability becomes good, and the water content after dehydration of the acrylic resin (C) becomes low. Further, when the concentration of polymer particles in the mixed suspension when adding the aqueous electrolyte solution is 35% by weight or less, the generation of secondary aggregated particles via the acrylic resin particles (b) is suppressed, and the water content after dehydration of the acrylic resin (C) becomes low.

[0065] The aqueous electrolyte solution is preferably added to the mixed suspension under stirring. By this operation, the acrylic resin particles (b) which are emulsion polymer particles are condensed (precipitated) on the surface of the acrylic resin particles (a) which are suspension polymer particles, covering the surface of the acrylic resin particles (a). The addition of the aqueous electrolyte solution needs to be carried out after mixing the suspension of suspension polymerization and the emulsion polymerization latex. The reason for this is that when the aqueous electrolyte solution is present during the mixing of the suspension of suspension polymerization and the emulsion polymerization latex, not only does the shape of the produced acrylic resin (C) become distorted and the water content after dehydration become high, but also the uncoagulated acrylic resin particles (b) remain and the filterability tends to deteriorate extremely. For example, when the aqueous electrolyte solution is added to the suspension of suspension polymerization and then the emulsion polymerization latex is added, problems such as a decrease in the uniformity of the coating of the acrylic resin particles (b) on the surface of the acrylic resin particles (a) and a significant increase in the remaining amount of the acrylic resin particles (b) which causes poor filterability occur.

[0066] As the electrolyte aqueous solution, an aqueous solution of an organic acid, an organic acid salt, an inorganic acid, and an inorganic salt having the property of being able to coagulate and solidify the acrylic resin particles (b) can be appropriately used. Examples of the electrolyte aqueous solution include aqueous solutions of inorganic salts such as sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, sodium iodide, potassium sulfate, sodium sulfate, ammonium sulfate, ammonium chloride, sodium nitrate, potassium nitrate, calcium chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, ferric chloride, magnesium chloride, ferric sulfate, aluminum sulfate, potassium alum, and iron alum; aqueous solutions of inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; organic acids such as acetic acid and formic acid and their aqueous solutions; and aqueous solutions of organic acid salts such as sodium acetate, calcium acetate, sodium formate, and calcium formate. These may be used alone or in combination of two or more. Among them, in terms of the uniformity of the coating of the acrylic resin particles (a) on the surface by the acrylic resin particles (b), the significant reduction of the remaining acrylic polymer particles (b) that causes deterioration of the filtration property, and the ease of wastewater treatment, aqueous solutions of inorganic salts such as sodium chloride, potassium chloride, sodium sulfate, ammonium chloride, calcium chloride, magnesium chloride, magnesium sulfate, barium chloride, ferrous chloride, aluminum sulfate, potassium alum, and iron alum, and aqueous solutions of inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid can be preferably used.

[0067] The concentration of the electrolyte aqueous solution is preferably 0.001% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1% by weight or more. If the concentration of the electrolyte aqueous solution is less than 0.001% by weight, it is necessary to add a large amount of the electrolyte aqueous solution to coagulate the acrylic resin particles (b), and the utility consumption during the subsequent heat treatment operation may be extremely large.

[0068] The addition of the aqueous electrolyte solution needs to be carried out at a temperature not higher than the Vicat softening temperature of the acrylic resin particles (b). If the temperature of the mixed suspension exceeds the Vicat softening temperature of the acrylic resin particles (b) during the addition of the aqueous electrolyte solution, the shape of the resulting acrylic resin (C) may be distorted and the water content after dehydration may increase. There is a tendency that the uncoagulated acrylic resin particles (b) remain, leading to extremely poor filterability, and a tendency that aggregation between the acrylic resins (C) frequently occurs.

[0069] After adding the aqueous electrolyte solution to the mixed suspension, when the aqueous electrolyte solution is an acidic aqueous solution and the mixed suspension after granulation shows acidity, it is neutralized with an alkali such as sodium hydroxide, or when the aqueous electrolyte solution is a neutral aqueous solution, it is directly heat-treated at a temperature higher than the Vicat softening temperature of the acrylic polymer particles (b), for example, 50°C or higher and 120°C or lower. By the heat treatment, the aggregates of the acrylic polymer particles (b) covering the surface of the acrylic polymer particles (a) are densified, and the water content of the obtained acrylic resin (C) decreases. Thereafter, dehydration and drying are carried out according to a conventional method, and the acrylic resin (C) can be obtained.

[0070] ≪Acrylic plasticizer (D1)≫ The acrylic plasticizer (D1) has a weight average molecular weight of 1,000 or more and 20,000 or less, preferably 1,000 or more and 18,000 or less, more preferably 1,000 or more and 15,000 or less, and even more preferably 1,000 or more and 13,000 or less. When the weight average molecular weight of the acrylic plasticizer (D1) is within the above-mentioned range, the shear viscosity of the carrier resin composition (B1) at 130°C is 1.0×10 2 Pa·s or more and 1.0×10 6 Pa·s or less, and the compatibility with the polycarbonate resin is also good. When the shear viscosity of the carrier resin composition (B1) at 130°C is 1.0×10 2 Pa·s or more and 1.0×10 6 Pa·s or less, the thermally expandable microcapsules (A) are likely to be uniformly dispersed in the carrier resin composition (B1).

[0071] The acrylic plasticizer (D1) is liquid at 20°C. This improves the processability of the masterbatch.

[0072] The acrylic plasticizer (D1) preferably has a viscosity at 25°C of 300 mPa·s or more and 100,000 mPa·s or less, more preferably 350 mPa·s or more and 90,000 mPa·s or less, and even more preferably 400 mPa·s or more and 80,000 mPa·s or less. When the viscosity of the acrylic plasticizer at 25°C is within the above-mentioned range, a carrier resin composition (B1) having a shear viscosity at 130°C of 1.0×10 2 Pa·s or more and 1.0×10 6 Pa·s or less is easily obtained. The viscosity of the acrylic plasticizer at 25°C can be measured using an E-type viscometer in accordance with JIS Z 8803-1991.

[0073] As the acrylic plasticizer (D1), those generally known as acrylic plasticizers can be used, and it is preferable to use a non-functional type acrylic plasticizer. Examples of the acrylic plasticizer include (meth)acrylic acid ester polymers, (meth)acrylic acid ester - aromatic vinyl monomer copolymers, etc., and (meth)acrylic acid ester polymers are preferable. The acrylic plasticizer preferably has 50% by weight or more, more preferably 70% by weight or more, of repeating units derived from (meth)acrylic acid esters in all repeating units.

[0074] (Meth)acrylic acid esters are not particularly limited, and examples thereof include alkyl acrylates having an alkyl group with 10 or fewer carbon atoms such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.; alkyl methacrylates having an alkyl group with 10 or fewer carbon atoms such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. These may be used alone or in combination of two or more. Among them, it is preferably at least one selected from the group consisting of methyl methacrylate, butyl methacrylate, ethyl acrylate, and butyl acrylate.

[0075] The aromatic vinyl monomer is not particularly limited, and examples thereof include styrene, α-methylstyrene, monochlorostyrene, dichlorostyrene, etc.

[0076] (Meth)acrylic acid ester polymers include homopolymers of alkyl acrylate esters, homopolymers of alkyl methacrylate esters, copolymers of alkyl acrylate esters with each other, copolymers of alkyl methacrylate esters with each other, and copolymers of alkyl acrylate esters and alkyl methacrylate esters.

[0077] The acrylic plasticizer (D1) is not particularly limited, and specifically, commercially available non-functional group type acrylic plasticizers such as product names "UP-1000", "UP-1010", "UP-1020", "UP-1021", and "UP-1061" manufactured by Toagosei Co., Ltd. can be used.

[0078] ≪Oil-absorbing powder (E)≫ The oil-absorbing powder (E) may be any compound having oil-absorbing properties, and either an inorganic compound or an organic compound may be used. Specifically, examples of the oil-absorbing powder (E) include inorganic compounds such as silica (including wet silica), silica diatomaceous earth, perlite, boron nitride, talc, mica, calcium carbonate, graphite (including natural graphite and artificial graphite), carbon black, and those obtained by subjecting these inorganic compounds to lipophilic treatment. One or more selected from the group consisting of silica, talc, and mica are preferred.

[0079] The oil-absorbing powder (E) preferably has an oil absorption of 5 mL / 100 g or more and 350 mL / 100 g or less, more preferably 10 mL / 100 g or more and 300 mL / 100 g or less, and still more preferably 20 mL / 100 g or more and 250 mL / 100 g or less. When the oil absorption of the oil-absorbing powder (E) is 5 mL / 100 g or more, the fluidity of the carrier resin composition (B1) or the mixture of the carrier resin composition (B1) and the thermally expandable microcapsules (A) is likely to increase, and the supplyability to the extruder is likely to be good. When the oil absorption of the oil-absorbing powder (E) is 350 mL / 100 g or less, the fluidity of the carrier resin composition (B1) or the mixture of the carrier resin composition (B1) and the thermally expandable microcapsules (A) is appropriately adjusted, and the mass productivity is good. In one or more embodiments of the present invention, the oil absorption of the oil-absorbing powder (E) is measured in accordance with JIS K5101-13-1, and is the amount of bis(2-ethylhexyl) adipate (DOA) absorbed by the oil-absorbing powder (E).

[0080] The oil-absorbing powder (E) is not particularly limited, but from the viewpoint of suppressing a decrease in the strength of the injection foam molded article using the masterbatch, the average particle size is preferably 0.01 μm or more and 100 μm or less, more preferably 0.2 μm or more and 50 μm or less, still more preferably 0.5 μm or more and 40 μm or less, and particularly preferably 1 μm or more and 30 μm or less. In one or more embodiments of the present invention, the average particle size of the oil-absorbing powder (E) can be measured by a general static light scattering method (laser diffraction, scattering method) or dynamic light scattering method (photon correlation method) according to the particle size and other properties.

[0081] The carrier resin composition (B1) may further contain a low molecular weight styrene resin (D2) having a weight average molecular weight of 1,000 or more and 150,000 or less.

[0082] ≪Low molecular weight styrene resin (D2)≫ The low molecular weight styrene resin (D2) has a weight average molecular weight of 1,000 or more and 150,000 or less, and is a liquid or a solid at 20°C. From the viewpoint of excellent handleability and easy mixing with other composition components such as the acrylic resin (C) in the carrier resin composition (B1), it is preferably a solid at 20°C. From the viewpoint of reducing the scattering of the carrier resin composition (B1), the thermally expandable microcapsules (A), and the mixture containing the carrier resin composition (B1), it is preferably a liquid at 20°C. The low molecular weight styrene resin (D2) may be a homopolymer of one styrene monomer or a copolymer of two or more styrene monomers. It may also be a copolymer of a styrene monomer and another copolymerizable monomer. In that case, the repeating unit derived from the styrene monomer only needs to be contained in an amount of 50% by weight or more, preferably 80% by weight or more, of the total repeating units.

[0083] Examples of the styrene monomer include styrene and styrene derivatives. Examples of the styrene derivative include methyl styrene, dimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, bromo styrene, dibromo styrene, tribromo styrene, chloro styrene, dichloro styrene, trichloro styrene, and the like. Among these, styrene is preferred.

[0084] Examples of the other copolymerizable monomers include polyfunctional vinyl compounds such as divinylbenzene; (meth)acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylonitrile; diene compounds such as butadiene and derivatives thereof; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride. These can be used alone or in combination of two or more.

[0085] From the viewpoint of processability, the low molecular weight styrene resin (D2) is preferably a homopolymer of styrene.

[0086] From the viewpoint of enhancing the compatibility with the polycarbonate resin, the weight average molecular weight of the low molecular weight styrene resin (D2) is preferably 130,000 or less, more preferably 100,000 or less, still more preferably 80,000 or less, and particularly preferably 40,000 or less. Also, from the viewpoint of improving the processability of the masterbatch, the weight average molecular weight of the low molecular weight styrene resin (D2) is preferably 2,000 or more, more preferably 5,000 or more, and still more preferably 10,000 or more. Specifically, the weight average molecular weight of the low molecular weight styrene resin (D2) is preferably 2,000 or more and 130,000 or less, more preferably 2,000 or more and 100,000 or less, still more preferably 5,000 or more and 80,000 or less, and particularly preferably 5,000 or more and 40,000 or less.

[0087] The low molecular weight styrene resin (D2) is not particularly limited, but preferably has a glass transition temperature of 25°C or higher and 130°C or lower. When the glass transition temperature of the low molecular weight styrene resin (D2) is 25°C or higher, it is easy to control the temperature of the extruder during the preparation of the masterbatch, and the processability is improved. Also, when the glass transition temperature of the low molecular weight styrene resin (D2) is 130°C or lower, the carrier resin composition is likely to have an appropriate viscosity during the preparation of the masterbatch, so that the thermally expandable microcapsules (A) do not foam and the processability is improved.

[0088] When the masterbatch contains the carrier resin composition (B1), the content of the acrylic plasticizer (D1) in the masterbatch is 0.1% by weight or more and 4% by weight or less. The tackiness of the carrier resin composition (B1) decreases and the fluidity improves, and therefore, the productivity of the masterbatch becomes good. The content of the acrylic plasticizer (D1) in the masterbatch is preferably 3% by weight or less. From the viewpoint of easily obtaining a masterbatch in which the thermally expandable microcapsules (A) are uniformly dispersed in the carrier resin composition (B1), the content of the acrylic plasticizer (D1) in the masterbatch is preferably 0.5% by weight or more, and more preferably 0.8% by weight or more. Specifically, the content of the acrylic plasticizer (D1) in the masterbatch is preferably 0.5% by weight or more and 4% by weight or less, more preferably 0.5% by weight or more and 3% by weight or less, and even more preferably 0.8% by weight or more and 3% by weight or less.

[0089]

[0090]

[0091] ​​When the masterbatch contains the carrier resin composition (B1), the content of the oil-absorbing powder (E) in the masterbatch is 0.1% by weight or more and less than 4% by weight. Thereby, without degrading the processability of the masterbatch, the adhesiveness of the carrier resin composition (B1) or a mixture of the carrier resin composition (B1) and the thermally expandable microcapsules (A) can be reduced, and the fluidity can be improved. Therefore, the productivity of the masterbatch becomes good. From the viewpoints of the fluidity of the carrier resin composition (B1) and the processability of the masterbatch, the content of the oil-absorbing powder (E) in the masterbatch is preferably 0.1% by weight or more and 3% by weight or less, more preferably 0.1% by weight or more and 2% by weight or less, and even more preferably 0.1% by weight or more and 1.5% by weight or less.

[0092] <carrier resin composition (B2)> The carrier resin composition (B2) contains an acrylic resin (C) and a low molecular weight styrene resin (D2). In the masterbatch containing the thermally expandable microcapsules (A) and the carrier resin composition (B2), the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and less than 12% by weight, preferably 0.5% by weight or more and 10% by weight or less, more preferably 0.5% by weight or more and 6% by weight or less, and even more preferably 0.5% by weight or more and 4% by weight or less. Thereby, it is easy to supply the carrier resin composition (B2) or a mixture of the carrier resin composition (B2) and the thermally expandable microcapsules (A) to an extruder, and the discharge amount of the melt-kneaded product can also be improved. As the acrylic resin (C) and the low molecular weight styrene resin (D2), those described in the "carrier resin composition (B1)" can be appropriately used. The low molecular weight styrene resin (D2) is preferably solid at 20°C from the viewpoint of excellent handleability and easy mixing with other composition components such as the acrylic resin (C) in the carrier resin composition (B2). The low molecular weight styrene resin (D2) is preferably liquid at 20°C from the viewpoint of reducing the scattering of the carrier resin composition (B2) or a mixture containing the thermally expandable microcapsules (A) and the carrier resin composition (B2). In the present invention, the carrier resin composition (B2) basically does not contain an acrylic plasticizer (D1) and an oil-absorbing powder (E).

[0093] The carrier resin composition (B2) may contain the oil-absorbing powder (E) within the range where the content of the oil-absorbing powder (E) in the masterbatch is less than 4% by weight. When the masterbatch contains the carrier resin composition (B2), the content of the oil-absorbing powder (E) in the masterbatch is preferably 0.1% by weight or more and 3% by weight or less, more preferably 0.1% by weight or more and 2% by weight or less, even more preferably 0.1% by weight or more and 1.5% by weight or less, and even more preferably 0.1% by weight or more and 1% by weight or less.

[0094] By using the carrier resin composition (B1) or the carrier resin composition (B2) having the above-described configuration as the carrier resin composition (B), the carrier resin composition (B) and the polycarbonate resin are substantially easy to be compatible with each other, and the shear viscosity at 130 ° C is 1.0×10 2 Pa·s or more and 1.0×10 6 Pa·s or less. Therefore, in the foamed resin molded body of the polycarbonate resin composition using the masterbatch of the thermally expandable microcapsule (A) masterbatch using the carrier resin composition (B), whitening is suppressed and the appearance becomes good. In the present invention, "substantially compatible with the polycarbonate resin" specifically means that in the differential scanning calorimetry (DSC) of the mixture of the carrier resin composition (B) and the polycarbonate resin, the detectable glass transition temperature becomes one.

[0095] Since the shear viscosity of the carrier resin composition (B) at 130 ° C is 1.0×10 2 Pa·s or more and 1.0×10 6 Pa·s or less, it becomes easy to obtain a masterbatch in which the thermally expandable microcapsule (A) is uniformly dispersed in the carrier resin composition (B). Specifically, at 130 ° C, when kneading the thermally expandable microcapsule (A) and the carrier resin composition (B) to prepare a masterbatch, since the viscosity of the carrier resin composition (B) is in an appropriate range, the thermally expandable microcapsule (A) is not sheared, As a result of suppressing shear heating, it becomes possible to pelletize the thermally expandable microcapsule (A) without expanding it. From the viewpoint of improving the processability of the masterbatch, the shear viscosity of the carrier resin composition (B) at 130 ° C is 1.0×10 3 Pa·s or more and 9.0x10 5 Pa·s or less is preferable, 2.0×10 3 Pa·s or more and 8.0x10 5 Pa·s or less is more preferable, and more preferably 3.0×10 3 Pa·s or more and 3.0x10 5 Pa·s or less, and even more preferably 5.0×10 3 Pa·s or more and 1.5x105 It is below Pa·s. The shear viscosity of the carrier resin composition (B) at 130°C can be measured using a flow tester (model CFT-500C) manufactured by Shimadzu Corporation. Specifically, the measurement start temperature is set at 50°C, a constant load of 30 kgf is applied to the carrier resin composition (B) to make it flow through a capillary with a diameter of 1.0 mm and a length of 10 mm, the temperature is raised at 10°C / min, and the shear viscosity at the time when the measurement temperature reaches 130°C is measured.

[0096] From the viewpoint of enhancing the low-temperature processability of the masterbatch, the carrier resin composition (B) has a shear viscosity of 1.0×10 2 Pa·s or more and 1.5×10 6 Pa·s or less at any temperature in the temperature range of 60°C or more and 100°C or less.

[0097] From the viewpoint of reducing the scattering of the carrier resin composition (B), the masterbatch containing the carrier resin composition (B), the thermally expandable microcapsules (A), and the mixture containing the carrier resin composition (B), it is preferably the carrier resin composition (B1) or the carrier resin composition (B2) containing a low-molecular-weight styrene-based resin (D2) that is liquid at 20°C, and more preferably the carrier resin composition (B1).

[0098] From the viewpoints of handleability, storage stability, dispersibility in the base resin, etc., the masterbatch preferably contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), more preferably 30% by weight or more and 70% by weight or less, and still more preferably 30% by weight or more and 60% by weight or less.

[0099] From the viewpoints of compatibility with the polycarbonate-based resin and processability, the masterbatch preferably contains 20% by weight or more and 70% by weight or less of the carrier resin composition (B), more preferably 30% by weight or more and 70% by weight or less, and still more preferably 40% by weight or more and 70% by weight or less.

[0100] When the masterbatch contains the carrier resin composition (B1), specifically from the viewpoints of compatibility with the polycarbonate resin, shear viscosity at 130°C, and handleability, storage stability, dispersibility in the base resin, etc., it is preferably contained 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 62.5% by weight or less of the acrylic resin (C), 0.1% by weight or more and 4% by weight or less of the acrylic plasticizer (D1), and 0.1% by weight or more and 3.5% by weight or less of the oil-absorbing powder (E); more preferably contained 31% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 62.5% by weight or less of the acrylic resin (C), 0.5% by weight or more and 3% by weight or less of the acrylic plasticizer (D1), and 0.1% by weight or more and 3.5% by weight or less of the oil-absorbing powder (E); still more preferably contained 35% by weight or more and 75% by weight or less of the thermally expandable microcapsules (A), 20% by weight or more and 60% by weight or less of the acrylic resin (C), 0.5% by weight or more and 3% by weight or less of the acrylic plasticizer (D1), and 0.1% by weight or more and 2% by weight or less of the oil-absorbing powder (E); and even more preferably contained 35.5% by weight or more and 75% by weight or less of the thermally expandable microcapsules (A), 20.5% by weight or more and 60% by weight or less of the acrylic resin (C), 0.5% by weight or more and 3% by weight or less of the acrylic plasticizer (D1), and 0.1% by weight or more and 1.5% by weight or less of the oil-absorbing powder (E).

[0101] When the masterbatch contains the carrier resin composition (B1), specifically from the viewpoints of compatibility with the polycarbonate resin, shear viscosity at 130°C, handleability, storage stability, dispersibility in the base resin, etc., it preferably contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 58.5% by weight or less of the acrylic resin (C), 0.1% by weight or more and 4% by weight or less of the acrylic plasticizer (D1), 0.1% by weight or more and 4% by weight or less of the low molecular weight styrene resin (D2), and 0.1% by weight or more and 3.5% by weight or less of the oil-absorbing powder (E). More preferably, it contains 33% by weight or more and 80% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 58% by weight or less of the acrylic resin (C), 0.5% by weight or more and 4% by weight or less of the acrylic plasticizer (D1), 0.5% by weight or more and 3% by weight or less of the low molecular weight styrene resin (D2), and 0.1% by weight or more and 2% by weight or less of the oil-absorbing powder (E). Even more preferably, it contains 34% by weight or more and 70% by weight or less of the thermally expandable microcapsules (A), 22% by weight or more and 58% by weight or less of the acrylic resin (C), 0.5% by weight or more and 3% by weight or less of the acrylic plasticizer (D1), 0.5% by weight or more and 3% by weight or less of the low molecular weight styrene resin (D2), and 0.1% by weight or more and 2% by weight or less of the oil-absorbing powder (E). Even more preferably, it contains 34.5% by weight or more and 70% by weight or less of the thermally expandable microcapsules (A), 22.5% by weight or more and 58% by weight or less of the acrylic resin (C), 0.5% by weight or more and 3% by weight or less of the acrylic plasticizer (D1), 0.5% by weight or more and 3% by weight or less of the low molecular weight styrene resin (D2), and 0.1% by weight or more and 1.5% by weight or less of the oil-absorbing powder (E).

[0102] When the masterbatch contains the carrier resin composition (B2), from the viewpoints of compatibility with the polycarbonate resin, shear viscosity at 130°C, and handleability, storage stability, dispersibility in the base resin, etc., specifically, it is preferably contained 30% by weight or more and 75% by weight or less of the thermally expandable microcapsules (A), 15% by weight or more and 60% by weight or less of the acrylic resin (C), and 0.1% by weight or more and 10% by weight or less of the low molecular weight styrene resin (D2). More preferably, it contains 34% by weight or more and 75% by weight or less of the thermally expandable microcapsules (A), 19% by weight or more and 60% by weight or less of the acrylic resin (C), and 0.5% by weight or more and 6% by weight or less of the low molecular weight styrene resin (D2). Even more preferably, it contains 36% by weight or more and 75% by weight or less of the thermally expandable microcapsules (A), 21% by weight or more and 60% by weight or less of the acrylic resin (C), and 0.5% by weight or more and 4% by weight or less of the low molecular weight styrene resin (D2).

[0103] <Method for producing masterbatch> In one or more embodiments of the present invention, the masterbatch is not particularly limited. For example, the thermally expandable microcapsules (A) and the carrier resin composition (B), specifically, the carrier resin composition (B1) or the carrier resin composition (B2) are mixed, and the obtained mixture is supplied to an extruder, melt-kneaded, and the obtained melt-kneaded product is extruded to produce it (hereinafter, also referred to as Embodiment 1). The strand after extrusion may be cut into pellets.

[0104] In Embodiment 1, the thermally expandable microcapsules (A) and the carrier resin composition (B), specifically, each component constituting the carrier resin composition (B) are not particularly limited. For example, by using a super mixer, Henschel mixer, floater, etc. for mixing, a mixture of the thermally expandable microcapsules (A) and the carrier resin composition (B) can be obtained.

[0105] In Embodiment 1, by using the carrier resin composition (B1) or the carrier resin composition (B2) having the above-described configuration as the carrier resin composition (B), the supplyability of the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder is good, the discharge amount of the melt-kneaded product is improved, and the productivity of the masterbatch is good.

[0106] In Embodiment 1, when the carrier resin composition (B1) is used as the carrier resin composition (B), the mixture of the thermally expandable microcapsules (A) and the carrier resin composition (B1) becomes a mixture of powder and liquid. When the carrier resin composition (B2) is used as the carrier resin composition (B), the mixture of the thermally expandable microcapsules (A) and the carrier resin composition (B2) becomes a mixture of powder and liquid or a powder mixture. When the mixture is put into a twin-screw type metering feeder, it is preferable that the mixture flows in the feeder by the rotation of the twin-screw and is discharged from the feeder. For example, as the twin-screw type metering feeder, a twin-screw type cassette weighing feeder (model number: CE-W-0) manufactured by Kubota Corporation is used. When 1 kg of the mixture is put into the feeder, it is preferable that the mixture flows moderately in the feeder by the rotation of the twin-screw and is discharged from the feeder. By using the carrier resin composition (B1) or the carrier resin composition (B2) as the carrier resin composition (B) in this way, the mixture does not adhere to the inner wall surface of the feeder, and by flowing moderately in the feeder by the rotation of the twin-screw, the raw material supplyability to the extruder is improved. From the viewpoint of being less likely to scatter during the supply of the raw material to the extruder, a mixture of powder and liquid obtained by mixing the thermally expandable microcapsules (A) and the carrier resin composition (B1) or a mixture of powder and liquid obtained by mixing the thermally expandable microcapsules (A) and the carrier resin composition (B2) containing the low molecular weight styrene-based resin (D2) that is liquid at 20°C is preferable, and a mixture of powder and liquid obtained by mixing the thermally expandable microcapsules (A) and the carrier resin composition (B1) is more preferable.

[0107] In one or more embodiments of the present invention, the masterbatch is not particularly limited. For example, the thermally expandable microcapsules (A) and the carrier resin composition (B), specifically the carrier resin composition (B1) or the carrier resin composition (B2), are each supplied to an extruder, and the thermally expandable microcapsules (A) and the carrier resin composition (B) are melt-kneaded, and the obtained melt-kneaded product can be produced by extruding it (hereinafter, also referred to as Embodiment 2). The extruded strand may be cut into pellets.

[0108] In Embodiment 2, the carrier resin composition (B), specifically the carrier resin composition (B1) or the carrier resin composition (B2), can be obtained by mixing each component using, for example, a super mixer, a Henschel mixer, a floater, etc., although not particularly limited.

[0109] By using the carrier resin composition (B1) or the carrier resin composition (B2) having the above-described configuration as the carrier resin composition (B), the supplyability of the carrier resin composition (B) to the extruder is good, the discharge amount of the melt-kneaded product is improved, and the productivity of the masterbatch becomes good.

[0110] In the melt-kneading, the thermally expandable microcapsules (A) and the carrier resin composition (B) may be supplied to the extruder from the same raw material supply port, or may be supplied to the extruder from different raw material supply ports. When the thermally expandable microcapsules (A) and the carrier resin composition (B) are supplied to the extruder from different raw material supply ports, the raw material supply port for supplying the carrier resin composition (B) is preferably arranged upstream in the extrusion direction from the raw material supply port for supplying the thermally expandable microcapsules (A).

[0111] The extruder used for melt-kneading is not particularly limited and may be a single-screw extruder or a twin-screw extruder. However, from the viewpoints of versatility and dispersibility, a twin-screw extruder is preferred. In Embodiment 1, the mixture is supplied from the raw material supply port to the extruder and melt-kneaded. In Embodiment 2, the thermally expandable microcapsules (A) and the carrier resin composition (B) are each supplied from the raw material supply port to the extruder and melt-kneaded. The melt-kneading temperature is not particularly limited, but for example, it is preferably 110°C or higher and 150°C or lower, and more preferably 120°C or higher and 140°C or lower. The discharge rate is preferably 3 kg / hour or more and 10 kg / hour or less, and more preferably 3 kg / hour or more and 7 kg / hour or less in the case of a 25 mm extruder.

[0112] <Polycarbonate-based resin composition> The polycarbonate-based resin composition contains the above-described masterbatch and a polycarbonate-based resin, and is a resin composition having a polycarbonate-based resin as the main component. Here, the "main component" means that the content of the polycarbonate-based resin is the largest among all the components contained in the polycarbonate-based resin composition. In the polycarbonate-based resin composition, the components excluding the masterbatch are also referred to as base components.

[0113] In the polycarbonate-based resin composition, the content of the masterbatch may be appropriately set according to the foaming ratio of the final product, the type of foaming agent, the resin temperature during molding, etc. The content of the masterbatch in the polycarbonate-based resin composition is preferably 1% by weight or more and 20% by weight or less, more preferably 2% by weight or more and 15% by weight or less, and particularly preferably 3% by weight or more and 10% by weight or less. By using the masterbatch within this range, a foaming ratio of 1.1 times or more can be economically achieved, and a foamed molded article with uniform and fine bubbles can be easily obtained.

[0114] The polycarbonate-based resin is a polycarbonate-based resin derived from a compound having two phenolic hydroxyl groups (hereinafter referred to as a dihydric phenol), and is usually a resin obtained by the reaction of a dihydric phenol with phosgene or a dihydric phenol with a carbonic acid diester.

[0115] Examples of the diphenol include bisphenol, methylene bisphenol (bisphenol F), bis(4-hydroxyphenyl) sulfone (bisphenol S), 2,2-bis(4-hydroxyphenyl) propane (bisphenol A), and the like. Among these, bisphenol A is preferred, but the invention is not limited thereto.

[0116] From the viewpoints of impact resistance, chemical resistance, and moldability, etc., the polycarbonate resin preferably has a number average molecular weight of 10,000 or more and 60,000 or less, more preferably 10,000 or more and 30,000 or less. The content of the polycarbonate resin in the polycarbonate resin composition is preferably 30% by weight or more and 99% by weight or less, more preferably 30% by weight or more and 80% by weight or less, and still more preferably 30% by weight or more and 70% by weight or less. In one or more embodiments of the present invention, the number average molecular weight of the resin is measured by GPC (gel permeation chromatography).

[0117] The polycarbonate resin composition may further contain one or more other thermoplastic resins selected from the group consisting of polyester resins, polyester-polyether copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-ethylene-propylene-diene-styrene copolymers, acrylate-styrene-acrylonitrile copolymers, acrylonitrile-styrene copolymers, polyarylate resins, and polystyrene resins. The polyester resin, polyester-polyether copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-ethylene-propylene-diene-styrene copolymer, acrylate-styrene-acrylonitrile copolymer, acrylonitrile-styrene copolymer, polyarylate resin, or polystyrene resin is not particularly limited, and for example, those described in International Publication No. 2019 / 208653 can be appropriately used.

[0118] From the perspective of effectively suppressing the whitening of the surface of the injection foam molded article and improving the appearance, the polycarbonate resin composition preferably contains 1% by weight or more and 15% by weight or less of the masterbatch, 30% by weight or more and 99% by weight or less of the polycarbonate resin, and 0% by weight or more and 55% by weight or less of one or more thermoplastic resins selected from the group consisting of polyester resins, polyester-polyether copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-ethylene-propylene-diene-styrene copolymers, acrylate-styrene-acrylonitrile copolymers, acrylonitrile-styrene copolymers, polyarylate resins, and polystyrene resins.

[0119] In order to improve the flexural rigidity and dimensional stability of the injection foam molded article, the polycarbonate resin composition may further contain an inorganic compound. Examples of the inorganic compound include one or more selected from the group consisting of mica, talc, montmorillonite, sericite, kaolin, glass flakes, plate-like alumina, synthetic hydrotalcite, wollastonite, hollow glass balloons, carbon fibers, aramid fibers, and whiskers. From the perspective of the effect of improving flexural rigidity and dispersibility in the polycarbonate resin, one or more selected from the group consisting of mica, talc, montmorillonite, sericite, kaolin, glass flakes, hollow glass beads, and carbon fibers are more preferable. From the perspective of the balance of impact resistance, fluidity, and product appearance, one or more selected from the group consisting of mica, talc, glass flakes, and wollastonite are even more preferable.

[0120] From the perspectives of impact resistance, heat resistance, rigidity, and moldability, etc., the inorganic compound is preferably contained in the polycarbonate resin composition in an amount of 5% by weight or more and 45% by weight or less, more preferably 5% by weight or more and 35% by weight or less, and even more preferably 5% by weight or more and 25% by weight or less.

[0121] In order to further improve the impact resistance of the injection foam molded article, the polycarbonate resin composition may further contain an impact resistance modifier. As the impact resistance improver, one or more selected from the group consisting of a multi-stage graft polymer, a polyolefin-based polymer, an olefin-unsaturated carboxylic acid ester copolymer, and a thermoplastic polyester-based elastomer are preferable.

[0122] From the viewpoints of impact resistance, heat resistance, rigidity, moldability, etc., the amount of the impact resistance modifier is preferably 0 to 20% by weight, more preferably 0 to 15% by weight, and still more preferably 0 to 10% by weight in the polycarbonate resin composition.

[0123] The polycarbonate resin composition may contain additives such as a flame retardant, a UV-resistant agent, a stabilizer, a release agent, a pigment, a softening agent, a plasticizer, and a surfactant, if necessary. The amount of these additives is preferably 0.01% by weight or more and 6% by weight or less, and more preferably 0.1% by weight or more and 4% by weight or less in the polycarbonate resin composition.

[0124] <Injection foam molded article> By injection foaming the polycarbonate resin composition, an injection foam molded article with suppressed whitening and good appearance can be obtained. Specifically, the injection foam molded article can be produced by a method of foaming the polycarbonate resin composition in a mold. The method of foaming in the mold is not particularly limited, and examples thereof include the core-back method, the short-shot method, and the full-fill method. Among them, the so-called core-back method (Moving Cavity method) is preferable, in which a mold composed of a fixed mold (also referred to as a cavity) and a movable mold (also referred to as a core) that can move forward and backward at an arbitrary position is used, and after the resin composition is completely injected to the initial filling thickness, the movable mold is retracted to cause foaming. According to the core-back method, a non-foamed layer is formed on the surface, smoothing the unevenness on the order of several μm to several tens of μm in appearance, and the internal foamed layer is likely to become uniform and fine bubbles, so that an injection foam molded article excellent in light weight is easily obtained, which is preferable.

[0125] In the core-back method, the retraction of the movable mold may be performed in one step, or in multiple steps of two or more steps, and the retraction speed may also be adjusted as appropriate. For example, it is composed of a fixed mold and a movable mold that can move forward and backward at any position, and the process of injecting and filling a mold with an initial cavity clearance t0 (initial filling thickness) of 1.5 mm or more and 2.7 mm or less, and after the injection filling is completed up to the initial filling thickness, the cavity clearance t f It is preferable to include a step of retracting the movable mold so that it becomes 2.0 mm or more and 6.0 mm or less and foaming.

[0126] In the core-back method, as other molding conditions, conditions such as a resin temperature of 240°C or more and 280°C or less, a mold temperature of 60°C or more and 90°C or less, a molding cycle of 1 second or more and 60 seconds or less, an injection speed of 10 mm / second or more and 400 mm / second or less, an injection pressure of 10 MPa or more and 200 MPa or less, a back pressure of 5 MPa or more and 40 MPa or less, and a screw rotation speed of 10 rpm or more and 200 rpm or less may be used.

[0127] The injection foam molded body is not particularly limited. For example, it can be suitably used for applications such as electrical appliances such as mobile phones and computer housings, vehicle exterior members such as license garnishes, pillar garnishes, slide rail covers, roof panels, and spoilers for automobiles, vehicle outer panel members such as fenders, door panels, back door panels, roofs, fuel lids, trunk lids, and retractable headlight panels, controller cases for industrial robots and cranes, controller cases and housings for game devices, frames, covers, and housings for VR / AR goggles, and exterior panels for drones.

[0128] From the viewpoints of weight reduction of the molded body and impact strength, the specific gravity of the injection foam molded body is 0.3 g / cm 3 or more and 1.2 g / cm 3 or less. When the specific gravity of the injection foam molded body is less than 0.3 g / cm 3 there is a tendency for the number of coarse bubbles exceeding 1.5 mm to increase and the impact strength to decrease, and when it is 1.2 g / cm 3When it exceeds [a certain value], it is difficult to achieve weight reduction. The specific gravity can be calculated by the water substitution method in accordance with JIS K 7112:1999. From the viewpoints of weight reduction and impact strength, the expansion ratio of the injection foam molded body is preferably 1.1 times or more and 3.0 times or less, more preferably 1.1 times or more and 2.5 times or less, and even more preferably 1.1 times or more and 2.0 times or less. When the expansion ratio is less than 1.1 times, it tends to be difficult to obtain light weight, and when it exceeds 3.0 times, the surface impact strength tends to decrease significantly. In this specification, the expansion ratio means the value obtained by dividing the thickness of the injection foam molded body (cavity clearance t f ) after core back by the initial cavity clearance t0.

Examples

[0129] The present invention will be described below based on specific examples and comparative examples, but the present invention is not limited to the following examples. In the following, unless otherwise specified, "parts" means parts by weight and "%" means % by weight.

[0130] Various measurement methods and evaluation methods are shown below.

[0131] (1) Glass transition temperature The glass transition temperature was measured using a differential scanning calorimeter (DSC220C manufactured by Seiko Instruments Inc.) under a temperature rising condition of 5°C / min. (2) Weight average molecular weight The weight average molecular weight of the resin was measured by GPC (gel permeation chromatography). Specifically, it was measured using a system: HLC-8220 manufactured by Tosoh Corporation, columns: two TSKgel SuperHZM-H manufactured by Tosoh Corporation, and solvent: THF, and the value obtained in terms of polystyrene conversion was used. (3) Average particle diameter The average particle diameter (when not expanded) of the thermally expandable microcapsules and the average particle diameter of the oil-absorbing powder were measured using a laser diffraction particle size distribution measuring device SALD-3000J manufactured by Shimadzu Corporation. (4) Oil absorption amount The oil absorption amount of the oil-absorbing powder was determined by measuring the amount of bis(2-ethylhexyl) adipate (DOA) absorbed by the oil-absorbing powder in accordance with JIS K5101-13-1. (5) Viscosity The viscosity of the acrylic plasticizer at 25°C was measured using an E-type viscometer in accordance with JIS Z 8803-1991. (6) Maximum expansion temperature "TMA measurement" was performed using a TMA-7 type manufactured by PerkinElmer. Approximately 0.25 mg of the sample of the thermally expandable microcapsules was placed in a container, heated at a heating rate of 5°C / min, and the displacement of its height was continuously measured. The temperature at which the displacement of the height of the sample in the container became maximum was defined as the maximum expansion temperature. (7) Shear viscosity The shear viscosity of the carrier resin composition (B) at 80°C or 130°C was measured using a flow tester "Model CFT-500C" manufactured by Shimadzu Corporation. Specifically, the measurement start temperature was set at 50°C, a constant load of 30 kgf was applied to the carrier resin composition (B) in a capillary having a diameter of 1.0 mm and a length of 10 mm to make it flow, heated at a rate of 10°C / min, and the shear viscosity at the time when the measurement temperature reached 80°C or 130°C was measured. (8) Raw material supplyability 1 kg of the mixture of the thermally expandable microcapsules (A) and the carrier resin composition (B) was put into a twin-screw type metering feeder for an extruder (manufactured by Kubota Corporation, twin-screw type cassette weighing feeder, model number: CE-W-0). Whether the supply of the mixture into the extruder proceeds by its own weight only by the rotation of the twin-screws at the bottom of the feeder without a stirring blade inside the feeder was confirmed, and the raw material supplyability was evaluated according to the following criteria. Good: The supply of the mixture into the extruder proceeds by its own weight. Poor: The supply of the mixture into the extruder does not proceed by its own weight. (9) Raw material scatterability Using the hopper part of a two - screw type metering feeder for an extruder (manufactured by Kubota Corporation, two - screw type cassette weighing feeder, model number: CE - W - 0), as shown in FIGS. 1 and 2, a gap 3 was provided at the joint of part 1 and part 2 so that the interval La was 0.5 mm. After a mixture of thermally expandable microcapsules (A) and carrier resin composition (B) was charged so as to reach from the upper part of part 1 to the joint of part 1 and part 2, part 1 was opened, and at the joint surface 4 of part 2, the scattering state of the raw material (mixture) was judged according to the following four - level criteria. In FIG. 1, Lb is 30 mm. 4: No scattering into the gap at all 3: Slight scattering into the gap (scattering < 15 mm at the joint surface) 2: Scattering occurs to a certain extent but mass production is possible (scattering < 25 mm at the joint surface) 1: Considerable scattering into the gap, causing considerable problems in mass production (scattering ≧ 25 mm at the joint surface) (10) Discharge amount of the melt - kneaded product Based on the discharge amount of the melt - kneaded product from the die of the extruder, it was evaluated according to the following criteria. Good: The discharge amount of the melt - kneaded product is 3 kg / hour or more Bad: The discharge amount of the melt - kneaded product is less than 3 kg / hour (11) Feasibility of masterbatch formation The cross - section of the masterbatch pellets was observed with a scanning electron microscope (SEM, manufactured by JEOL Ltd., model "JSM - 6060LA"), and the processability of the masterbatch was evaluated based on the state of the thermally expandable microcapsules. Acceptable: No expansion of the thermally expandable microcapsules and no fuzz formation on the pellets Unacceptable: No expansion of the thermally expandable microcapsules, but fuzz formation occurs on the pellets (12) Compatibility with polycarbonate - based resin (PC) Differential scanning calorimetry (DSC) was performed on a mixture of the carrier resin composition (B) and polycarbonate - based resin, and the presence or absence of compatibility with PC was judged according to the following criteria. Compatible: In DSC, there is one glass transition temperature Incompatible: In DSC, there are two glass transition temperatures

[0132] <Production Example 1 of Acrylic Resin (C)> <Preparation of Acrylic Resin Particles (a)> Into a reactor equipped with a stirrer, 220 parts of deionized water and 15 parts of a 3%-PVA aqueous solution (GH-20: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) were charged, and the inside of the reactor was purged with nitrogen. Then, a monomer mixture of 25 parts of butyl acrylate and 75 parts of methyl methacrylate in which 0.5 part of lauroyl peroxide, 0.5 part of benzoyl peroxide, and 0.5 part of 2-ethylhexyl thioglycolate were dissolved was added, and the rotation speed of the stirrer was adjusted so that the dispersed particle diameter of the monomer was about 250 μm. Thereafter, the temperature was raised stepwise at 60 °C for 2 hours, 70 °C for 2 hours, 80 °C for 2 hours, and 90 °C for 1 hour to complete the polymerization, and a suspension of acrylic resin particles (a) (polymer solid content) having a concentration of 30%, a glass transition temperature of 72 °C, and an average particle diameter of 150 μm was prepared.

[0133] <Preparation of Acrylic Resin Particles (b)> 220 parts of deionized water, 0.3 part of boric acid, 0.03 part of sodium carbonate, 0.09 part of sodium N-lauroyl sarcosinate, 0.09 part of sodium formaldehyde sulfoxylate, 0.006 part of sodium ethylenediaminetetraacetate, and 0.002 part of ferrous sulfate heptahydrate were charged into a reactor equipped with a stirrer. After nitrogen substitution, the temperature was raised to 80°C. 25% of a monomer mixture consisting of 25 parts of methyl methacrylate, 0.1 part of allyl methacrylate, and 0.1 part of t-butyl hydroperoxide was charged all at once, and polymerization was carried out for 45 minutes. Subsequently, the remaining 75% of this mixed solution was continuously added over 1 hour. After the addition was completed, it was held at the same temperature for 2 hours to complete the polymerization. Also, 0.2 part of sodium N-lauroyl sarcosinate was added during this period. The average particle diameter of the polymer particles in the latex of the obtained innermost layer crosslinked methacrylic polymer was 1600 Å (determined using light scattering at a wavelength of 546 nm), and the polymerization conversion rate (polymer production amount / monomer charged amount x 100) was 98%. Subsequently, the latex of the obtained innermost layer crosslinked methacrylic polymer was kept at 80°C in a nitrogen stream. After adding 0.1 part of potassium persulfate, a monomer mixed solution of 41 parts of n-butyl acrylate, 9 parts of styrene, and 1 part of allyl methacrylate was continuously added over 5 hours. During this period, 0.1 part of potassium oleate was added in three portions. After the addition of the monomer mixed solution was completed, 0.05 part of potassium persulfate was further added to complete the polymerization and it was held for 2 hours. In the obtained latex of the emulsion polymerization, the average particle diameter of the latex particles (b1) was 2300 Å, and the polymerization conversion rate was 99%. Subsequently, the latex of the latex particles (b1) was kept at 80°C. After adding 0.02 part of potassium persulfate, a mixed solution of 24 parts of methyl methacrylate, 1 part of n-butyl acrylate, and 0.1 part of t-dodecyl mercaptan was continuously added over 1 hour. After the addition of the monomer mixed solution was completed, it was held for 1 hour to obtain a latex of an emulsion polymerization graft copolymer (acrylic resin particles (b)) having a multilayer structure, an average particle diameter of 0.25 μm, and a Vicat softening temperature of 90°C.

[0134] <Preparation of Acrylic Resin (C)> 96 parts of the latex of the obtained acrylic resin particles (b) (solid content, i.e., 30 parts of acrylic resin particles (b)) and 332 parts of the suspension of acrylic resin particles (a) (solid content, i.e., 100 parts of acrylic resin particles (a)) were mixed under stirring. The obtained mixed suspension (solid content, i.e., the total concentration of acrylic resin particles (a) and acrylic resin particles (b) is 30%) was adjusted to 60°C, and then 50 parts of a 1.0% calcium chloride aqueous solution was added dropwise under stirring over 10 minutes. Thereafter, the temperature was raised to 95°C under stirring for heat treatment to obtain acrylic resin (C) with an average particle diameter of 200 μm. The weight average molecular weight of acrylic resin (C) was 60,000, and the glass transition temperature (Tg) was 77°C.

[0135] (Example 1) The acrylic resin (C) obtained above, an acrylic plasticizer (D1) (manufactured by Toagosei Co., Ltd., "Alphon UP1020", weight average molecular weight 2000, liquid at 20°C, viscosity at 25°C 500 mPa·s, all-acrylic, no functional group), an oil-absorbing powder (E) (silica particles, wet silica, average particle diameter 11.5 μm, oil absorption 225 mL / 100 g, manufactured by Evonik Japan Co., Ltd., product name "Carplex", model number "#67"), and a thermally expandable microcapsule (A) (manufactured by Kureha Corporation, "Microsphere S2640D", average particle diameter 21 μm, maximum expansion temperature 249°C) were mixed in a super mixer (manufactured by Kawata Co., Ltd., capacity 10 L) at the compounding ratios shown in Table 1 below. After that, the obtained mixture was supplied to a co-rotating twin-screw extruder (manufactured by Technovel, 25 mm extruder) by a gravimetric feeder and melt-kneaded at 130°C. After the strand was water-cooled, it was cut by a pelletizer to obtain a pelletized masterbatch of thermally expandable microcapsules.

[0136] (Examples 2 to 4) The compounding ratio of the acrylic plasticizer (D1) was changed as shown in Table 1 below, and in addition, a low molecular weight styrene-based resin (D2) (styrene homopolymer, weight average molecular weight 2,500, solid at 20°C, glass transition temperature 50°C, "Resit S-94" manufactured by Sanyo Chemical Industries, Ltd.) was added so as to have the compounding ratio shown in Table 1 below. Otherwise, a masterbatch was prepared in the same manner as in Example 1.

[0137] (Example 5) A masterbatch was prepared in the same manner as in Example 1, except that the acrylic plasticizer (D1) and the oil-absorbing powder (E) were not used, and the blending ratio of the acrylic resin (C) was changed as shown in Table 1 below, and the low molecular weight styrene resin (D2) was added so as to have the blending ratio shown in Table 1 below.

[0138] (Comparative Example 1) A masterbatch was prepared in the same manner as in Example 1, except that the oil-absorbing powder (E) was not used, and the blending ratios of the acrylic resin (C) and the acrylic plasticizer (D1) were changed as shown in Table 2 below.

[0139] (Comparative Example 2) A masterbatch was prepared in the same manner as in Example 1, except that the blending ratios of the acrylic resin (C), the acrylic plasticizer (D1), and the oil-absorbing powder (E) were changed as shown in Table 2 below.

[0140] (Comparative Examples 3 - 6) A masterbatch was prepared in the same manner as in Example 2, except that the blending ratios of the acrylic resin (C), the acrylic plasticizer (D1), the low molecular weight styrene resin (D2), and the oil-absorbing powder (E) were changed as shown in Table 2 below.

[0141] (Comparative Example 7) A masterbatch was prepared in the same manner as in Example 5, except that the blending ratios of the acrylic resin (C), the low molecular weight styrene resin (D2), and the oil-absorbing powder (E) were changed as shown in Table 2 below.

[0142] In the examples and comparative examples, the raw material supplyability, the discharge amount of the melt-kneaded product, and the processability of the masterbatch were evaluated as described above, and the results are shown in Tables 1 and 2 below. Also, in the examples and comparative examples, the shear viscosities of the carrier resin composition (B) at 80°C and 130°C were measured as described above, and the results are shown in Tables 1 and 2 below.

[0143]

Table 1

[0144]

Table 2

[0145] As can be seen from Table 1 above, in the examples using the carrier resin composition (B1) or the carrier resin composition (B2) as the carrier resin composition (B), the supplyability of the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder was good, the discharge amount of the melt-kneaded product was also high, and the masterbatch could be obtained with good productivity. Further, from the comparison between Examples 1 to 4 and Example 5, it can be seen that when using the carrier resin composition (B1) as the carrier resin composition (B), the scattering of the raw materials is suppressed and the mass productivity is excellent.

[0146] On the other hand, as can be seen from Table 2, in the case of Comparative Example 1 using a carrier resin composition containing an acrylic plasticizer (D1) but not containing an oil-absorbing powder (E), the supplyability of the mixture of the thermally expandable microcapsules and the carrier resin composition to the extruder was poor, and the discharge amount of the melt-kneaded product was also low. Further, in the case of Comparative Examples 2 to 7 using a carrier resin composition containing an oil-absorbing powder (E) but with the content of the oil-absorbing powder (E) in the masterbatch being 4% by weight or more, the masterbatch could not be obtained. In Comparative Examples 2 to 7, since the fuzzing was intense and the kneading was poor, the pellets for measurement could not be processed, and therefore, the shear viscosity of the carrier resin composition (B) at 80°C could not be measured.

[0147] The present invention is not particularly limited, but includes, for example, the following aspects. [1] A masterbatch containing a thermally expandable microcapsule (A) and a carrier resin composition (B), wherein the carrier resin composition (B) is a carrier resin composition (B1) or a carrier resin composition (B2), The carrier resin composition (B1) has a weight average molecular weight of 8,000 or more and 350,000 or less, and an acrylic resin (C) that is solid at 20°C, an acrylic plasticizer (D1) having a weight average molecular weight of 1,000 or more and 20,000 or less, and an oil-absorbing powder (E), The carrier resin composition (B2) has a weight average molecular weight of 8,000 or more and 350,000 or less, and an acrylic resin (C) that is solid at 20°C, and a low molecular weight styrene resin (D2) having a weight average molecular weight of 1,000 or more and 150,000 or less, and being liquid or solid at 20°C, When the carrier resin composition (B) is the carrier resin composition (B1), in the masterbatch, the content of the acrylic plasticizer (D1) is 0.1% by weight or more and 4% by weight or less, and the content of the oil-absorbing powder (E) is 0.1% by weight or more and less than 4% by weight, When the carrier resin composition (B) is the carrier resin composition (B2), in the masterbatch, the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and less than 12% by weight, characterized in that, masterbatch. [2] The low molecular weight styrene resin (D2) has a glass transition temperature of 25°C or more and 130°C or less, the masterbatch according to [1]. [3] The oil-absorbing powder (E) is one or more selected from the group consisting of silica, silica diatomaceous earth, perlite, boron nitride, talc, mica, calcium carbonate, graphite and carbon black, the masterbatch according to [1] or [2]. [4] The oil absorption amount of the oil-absorbing powder (E) is 5 mL / 100 g or more and 350 mL / 100 g or less, the masterbatch according to any one of [1] to [3]. [5] The average particle diameter of the oil-absorbing powder (E) is 0.01 μm or more and 100 μm or less, the masterbatch according to any one of [1] to [4]. [6] The carrier resin composition (B1) further contains a low molecular weight styrene resin (D2), and in the masterbatch, the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and 4% by weight or less, the masterbatch according to any one of [1] to [5]. [7] The carrier resin composition (B) is the masterbatch according to any one of [1] to [6] having compatibility with a polycarbonate resin. [8] The thermally expandable microcapsule (A) has a core-shell structure and is composed of a core composed of one or more compounds having a boiling point of 10 ° C or higher and 330 ° C or lower, and a shell encapsulating the core. The shell is composed of a resin having a structural unit derived from one or more monomers selected from the group consisting of a nitrile monomer, a (meth) acrylate monomer, an aromatic vinyl monomer, a diene monomer, a vinyl monomer having a carboxyl group, and a monomer having one or more reactive functional groups selected from the group consisting of a methylol group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group. The masterbatch according to any one of [1] to [7]. [9] The masterbatch according to any one of [1] to [8], wherein the maximum expansion temperature of the thermally expandable microcapsule (A) is 210 ° C or higher and 270 ° C or lower.

[10] The shear viscosity of the carrier resin composition (B) at 130 ° C is 1.0x10 2 Pa·s or more and 1.0x10 6 Pa or less. The masterbatch according to any one of [1] to [9].

[11] The masterbatch according to any one of [1] to

[10] , wherein the masterbatch contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsule (A) and 20% by weight or more and 70% by weight or less of the carrier resin composition (B1) or the carrier resin composition (B2).

[12] A method for producing the masterbatch according to any one of [1] to

[11] , A step of mixing the thermally expandable microcapsule (A) and the carrier resin composition (B), A step of supplying the obtained mixture to an extruder and melt-kneading it, A method for producing a masterbatch, including a step of extruding the obtained melt-kneaded product.

[13] A method for producing the masterbatch according to any one of [1] to

[11] , A step of supplying the thermally expandable microcapsules (A) and the carrier resin composition (B) to an extruder respectively and melt-kneading the thermally expandable microcapsules (A) and the carrier resin composition (B); A method for producing a masterbatch, comprising a step of extruding the obtained melt-kneaded product.

[14] A mixture containing the thermally expandable microcapsules (A) and the carrier resin composition (B), wherein the thermally expandable microcapsules (A) and the carrier resin composition (B) are the thermally expandable microcapsules (A) and the carrier resin composition (B) described in any one of [1] to

[11] respectively; when the carrier resin composition (B) is the carrier resin composition (B1), the mixture is a mixture of powder and liquid, and when the carrier resin composition (B) is the carrier resin composition (B2), the mixture is a mixture of powder and liquid or a powder mixture; The mixture is characterized in that when the mixture is put into a twin-screw type metering feeder, the mixture flows in the feeder by the rotation of the twin-screw and is discharged from the feeder.

[15] A polycarbonate resin composition containing the masterbatch described in any one of [1] to

[11] and a polycarbonate resin.

[16] The polycarbonate resin composition according to

[15] , wherein the content of the masterbatch in the polycarbonate resin composition is 1% by weight or more and 20% by weight or less.

[17] The polycarbonate resin composition according to

[15] or

[16] , wherein the polycarbonate resin composition further contains one or more other thermoplastic resins selected from the group consisting of a polyester resin, a polyester-polyether copolymer, an acrylonitrile-butadiene-styrene copolymer, an acrylonitrile-ethylene-propylene-diene-styrene copolymer, an acrylate-styrene-acrylonitrile copolymer, an acrylonitrile-styrene copolymer, a polyarylate resin, and a polystyrene resin.

[18] An injection foam molded article, characterized in that the polycarbonate resin composition according to any one of

[15] to

[17] is injection foam molded.

[19] The injection foam molded article according to

[18] , wherein the injection foam molded article is an electric appliance product, a vehicle member, a vehicle exterior, or an outer panel for a vehicle.

[20] The injection molded article according to

[18] or

[19] , wherein the expansion ratio of the injection foam molded article is 1.1 times or more and 3.0 times or less.

[21] A method for producing an injection foam molded article by injection foam molding the polycarbonate resin composition according to any one of

[15] to

[17] .

[22] The method for producing an injection molded article according to

[21] , wherein the injection foam molding is one or more selected from the group consisting of a core-back method, a short-shot method, and a full-fill method.

Explanation of reference numerals

[0148] Parts of the hopper section of the 1, 2 metering feeder 3 Gap 4 Joint surface

Claims

1. A masterbatch containing a thermally expandable microcapsule (A) and a carrier resin composition (B), wherein the carrier resin composition (B) is a carrier resin composition (B1) or a carrier resin composition (B2), the carrier resin composition (B1) has a weight average molecular weight of 8,000 or more and 350,000 or less, and is a solid acrylic resin (C) at 20°C, has a weight average molecular weight of 1,000 or more and 20,000 or less, and is a liquid acrylic plasticizer (D1) at 20°C, and an oil-absorbing powder (E), the carrier resin composition (B2) has a weight average molecular weight of 8,000 or more and 350,000 or less, and is a solid acrylic resin (C) at 20°C, and a low molecular weight styrene resin (D2) having a weight average molecular weight of 1,000 or more and 150,000 or less, and being liquid or solid at 20°C, when the carrier resin composition (B) is the carrier resin composition (B1), in the masterbatch, the content of the acrylic plasticizer (D1) is 0.1% by weight or more and 4% by weight or less, and the content of the oil-absorbing powder (E) is 0.1% by weight or more and less than 4% by weight, when the carrier resin composition (B) is the carrier resin composition (B2), in the masterbatch, the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and less than 12% by weight, the carrier resin composition (B2) does not contain the acrylic plasticizer (D1) and contains less than 4% by weight of the oil-absorbing powder (E), characterized in that it is a masterbatch.

2. The masterbatch according to Claim 1, wherein the low molecular weight styrene resin (D2) has a glass transition temperature of 25°C or more and 130°C or less.

3. The masterbatch according to Claim 1 or 2, wherein the oil-absorbing powder (E) is at least one selected from the group consisting of silica, silica diatomaceous earth, perlite, boron nitride, talc, mica, calcium carbonate, graphite, and carbon black.

4. The masterbatch according to any one of Claims 1 to 3, wherein the oil absorption amount of the oil-absorbing powder (E) is 5 mL / 100 g or more and 350 mL / 100 g or less.

5. The masterbatch according to any one of Claims 1 to 4, wherein the average particle diameter of the oil-absorbing powder (E) is 0.01 μm or more and 100 μm or less.

6. The carrier resin composition (B1) further contains a low molecular weight styrene resin (D2), and in the masterbatch, the content of the low molecular weight styrene resin (D2) is 0.1% by weight or more and 4% by weight or less. The masterbatch according to any one of claims 1 to 5.

7. The masterbatch according to any one of claims 1 to 6, wherein the carrier resin composition (B) has compatibility with a polycarbonate resin.

8. The thermally expandable microcapsule (A) has a core-shell structure and is composed of a core composed of one or more compounds having a boiling point of 10 ° C or higher and 330 ° C or lower, and a shell that encapsulates the core. The shell is composed of a resin having a structural unit derived from one or more monomers selected from the group consisting of nitrile monomers, (meth) acrylate monomers, aromatic vinyl monomers, diene monomers, vinyl monomers having a carboxyl group, and monomers having one or more reactive functional groups selected from the group consisting of a methylol group, a hydroxyl group, an amino group, an epoxy group, and an isocyanate group. The masterbatch according to any one of claims 1 to 7.

9. The masterbatch according to any one of claims 1 to 8 contains 30% by weight or more and 80% by weight or less of the thermally expandable microcapsule (A) and 20% by weight or more and 70% by weight or less of the carrier resin composition (B1) or the carrier resin composition (B2).

10. A method for producing the masterbatch according to any one of claims 1 to 9, A step of mixing the thermally expandable microcapsule (A) and the carrier resin composition (B), A step of supplying the obtained mixture to an extruder and melt-kneading it, A method for producing a masterbatch, comprising a step of extruding the obtained melt-kneaded product.

11. A method for producing the masterbatch according to any one of claims 1 to 9, A step of supplying the thermally expandable microcapsule (A) and the carrier resin composition (B) to an extruder respectively and melt-kneading the thermally expandable microcapsule (A) and the carrier resin composition (B), A method for producing a masterbatch, comprising a step of extruding the obtained melt-kneaded product.

12. A mixture containing a thermally expandable microcapsule (A) and a carrier resin composition (B), The thermally expandable microcapsules (A) and the carrier resin composition (B) are respectively the thermally expandable microcapsules (A) and the carrier resin composition (B) according to any one of claims 1 to 9. When the carrier resin composition (B) is the carrier resin composition (B1), the mixture is a mixture of powder and liquid. When the carrier resin composition (B) is the carrier resin composition (B2), the mixture is a mixture of powder and liquid or a powder mixture. A mixture, characterized in that when the mixture is fed into a twin-screw type metering feeder, the mixture flows in the feeder by the rotation of the twin-screw and is discharged from the feeder.

13. A polycarbonate resin composition containing a masterbatch according to any one of claims 1 to 9 and a polycarbonate resin.

14. An injection foam molded article, characterized in that the polycarbonate resin composition according to claim 13 is injection foam molded.

15. A method for producing an injection foam molded article by injection foam molding the polycarbonate resin composition according to claim 13.

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