Method for producing thermoplastic resin composition

Abstract

To provide a production method capable of obtaining a thermoplastic resin composition with a good filler dispersion state.SOLUTION: There is provided a method for producing a thermoplastic resin composition. The production method uses a twin-screw extruder that is configured in that: a cylinder having a L / D value of 30 or more is provided with first supply means 21, second supply means 22, first discharge means 31, and heating means; a distance 22L from an upstream end 11 of the cylinder of the second supply means is 60% or less of a length L of the cylinder; a distance 31L from the upstream end of the cylinder of the first discharge means is 40% or less of the length of the cylinder; and a distance from the upstream end of the cylinder of the second supply means is longer than the distance from the upstream end of the cylinder of the first discharge means. The production method comprises a kneading step of melt-mixing a material to be kneaded, the material including a thermoplastic resin (A) having a specific gravity of 1 or more and an aqueous dispersion (B) containing a filler, and in the kneading step, a full-filled region filled with the material to be kneaded in a direction perpendicular to the length direction of the cylinder is formed from a position in the downstream side of the second supply means in the cylinder by 10% or more of the length of the cylinder toward the downstream side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a thermoplastic resin composition. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a resin composition in the form of pellets containing a thermoplastic resin and organic particles and / or inorganic particles called a filler has been widely used as a material for molded articles. Such a resin composition is generally produced by melt-mixing materials containing a thermoplastic resin and organic particles and / or inorganic particles using an extruder, and molding the materials into pellets.

[0003] However, such a production method tends to cause the organic particles and / or inorganic particles to aggregate and produce coarse particles, and it may not be possible to obtain a pellet-shaped resin composition in which the organic particles and / or inorganic particles are well dispersed. For this reason, a method has been proposed for producing a pellet-shaped resin composition by producing an aqueous dispersion containing organic particles and / or inorganic particles, and supplying the aqueous dispersion and a thermoplastic resin to the cylinder of an extruder to melt-mix them.

[0004] Examples of methods for supplying a solid material and a liquid material to the cylinder of an extruder and melt-mixing them include the methods described in Patent Documents 1 to 4. Patent Document 1 proposes a method in which pellets of an ethylene polymer and a liquid are charged into a hopper, kneaded in a single-screw extruder, and extrusion-molded through a die.

[0005] Patent Document 2 describes a method for producing a sheet-like product, in which a resin is fed into a cylinder from a raw material supply port at the most upstream part of an extrusion molding machine, an organic peroxide is then added into the cylinder between the raw material supply port and the tip of the screw using a liquid addition nozzle, the resin and the organic peroxide are mixed in the extrusion molding machine, and then the resin is extruded from a die at the tip of the extrusion molding machine.

[0006] Patent Documents 3 and 4 describe a method for producing a polyester resin composition in which polyester and inorganic and / or organic fine particles are added to a vented twin-screw kneading extruder and kneaded. Patent Documents 3 and 4 also describe that inorganic particles and / or organic fine particles may be made into a slurry or solution and fed to the vented twin-screw kneading extruder through a liquid addition nozzle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2011-207217 A [Patent Document 2] JP 2010-253881 A [Patent Document 3] JP 2006-63246 A [Patent Document 4] JP 2006-63210 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in a thermoplastic resin composition containing a thermoplastic resin and a filler produced by a conventional production method, there has been a demand for improving the dispersion state of the filler contained in the thermoplastic resin composition. The present invention has been made in consideration of the above circumstances, and aims to provide a method for producing a thermoplastic resin composition that contains a thermoplastic resin and a filler and that can produce a thermoplastic resin composition in which the filler is well dispersed. [Means for solving the problem]

[0009] [1] A cylinder that accommodates two screws and has a ratio of length L to inner diameter L, L / D, of 30 or more; The cylinder is provided with a first supplying means for supplying a solid material into the cylinder, a second supplying means for supplying a liquid material into the cylinder, a first discharging means for discharging a gas in the cylinder, and a heating means for heating the inside of the cylinder; the distance of the second supply means from the upstream end of the cylinder is 60% or less of the length L of the cylinder; The distance of the first discharge means from the upstream end of the cylinder is 40% or less of the length L of the cylinder, Using a twin-screw kneading extruder, a distance of the second supplying means from an upstream end of the cylinder is longer than a distance of the first discharging means from an upstream end of the cylinder, The method includes a kneading step of melt-mixing a material to be kneaded, the material including a thermoplastic resin (A) having a specific gravity of 1 or more and an aqueous dispersion (B) containing a filler, In the kneading step, the thermoplastic resin (A) is supplied from the first supply means, and the aqueous dispersion (B) is supplied from the second supply means; While rotating the two screws to knead and convey the material to be kneaded, the material to be kneaded is heated by the heating means to melt the thermoplastic resin (A) and gas generated from the material to be kneaded is discharged from the first discharge means; A method for producing a thermoplastic resin composition, comprising forming a fully-filled region in the cylinder, filled with the material to be mixed in a direction perpendicular to the longitudinal direction of the cylinder, from a position in the cylinder that is 10% or more downstream of the second supply means toward the downstream side.

[0010] [2] The method for producing a thermoplastic resin composition according to [1], wherein the thermoplastic resin (A) in pellet form is supplied from the first supply means. [3] The method for producing a thermoplastic resin composition according to [1], wherein the thermoplastic resin (A) is one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyamide-6, polyphenylene sulfide, and polycarbonate.

[0011] [4] The method for producing a thermoplastic resin composition according to [1], wherein the particle size of the filler is 0.01 μm to 3 μm. [5] The method for producing a thermoplastic resin composition according to [1], wherein the filler comprises inorganic particles and / or organic particles.

[0012] [6] The cylinder has one or more second exhaust means downstream of the full-filling region for exhausting gas from within the cylinder; The method for producing a thermoplastic resin composition according to [1], wherein in the kneading step, the gas in the cylinder is discharged from the second discharge means to reduce the pressure in the cylinder.

[0013] [7] The method for producing a thermoplastic resin composition according to [1], wherein the aqueous dispersion (B) contains a surfactant. [8] The method for producing a thermoplastic resin composition according to [1], wherein the content of the filler in the kneaded material is 0.01% by mass to 50% by mass, when the total mass of the thermoplastic resin (A) and the filler is 100% by mass. Effect of the Invention

[0014] According to the production method of the present invention, a thermoplastic resin composition containing a thermoplastic resin and a filler, in which the filler is well dispersed, can be obtained. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing an example of a twin-screw kneading extruder used in the method for producing a thermoplastic resin composition of this embodiment, and is an explanatory diagram for explaining a cylinder 10 of the twin-screw kneading extruder. [Diagram 2] FIG. 2 is a cross-sectional view of the cylinder 10 taken along line AA' in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The manufacturing method of the thermoplastic resin composition of the present invention will be described in detail below with reference to the drawings. The drawings used in the following description may be enlarged to show the characteristic parts for the sake of convenience in order to make the features of the present invention easier to understand. Therefore, the dimensional ratios of each component may differ from the actual ones. The scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. In addition, when multiple upper and lower limit values ​​are described for a specific parameter, any upper and lower limit values ​​can be combined to form a suitable numerical range.

[0017] [Method of producing thermoplastic resin composition] The method for producing a thermoplastic resin composition according to the present embodiment includes a kneading step of melt-mixing materials to be kneaded using a twin-screw kneading extruder. [Material to be mixed] The material to be kneaded contains a thermoplastic resin (A) and a water dispersion (B).

[0018] (Thermoplastic resin (A)) The thermoplastic resin (A) may be any thermoplastic resin having a specific gravity of at least 1. Since the specific gravity of the thermoplastic resin (A) is at least 1, in the kneading step in the production method of this embodiment, the thermoplastic resin (A) in the kneaded material containing the water dispersion (B) can be prevented from floating up and flowing out of the first discharge means provided in the cylinder of the twin-screw kneading extruder.

[0019] As the thermoplastic resin (A), for example, known thermoplastic resins such as polyester resins, polyamide resins, polyphenylene resins, polycarbonate resins, ethylene-unsaturated ester copolymers, poly(meth)acrylic resins, fluorine resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polyetherketone resins, polyarylate resins, polyarylene sulfide resins, etc. can be used, and can be appropriately selected depending on the intended use of the thermoplastic resin composition, which is the target product. As the thermoplastic resin (A), only one selected from the above thermoplastic resins may be used alone, or two or more may be used in combination.

[0020] Examples of polyester-based resins used as the thermoplastic resin (A) include polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate (PBT), polyhexylene terephthalate, polycyclohexylene dimethylene terephthalate (PCT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polycyclohexane dimethyl phthalate (PCN), polytrimethylene naphthalate (PTN), amorphous polyester resins (PETG, PCTG), polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate, polyethylene isophthalate / terephthalate, and polybutylene terephthalate / isophthalate.

[0021] When the thermoplastic resin composition produced by the production method of this embodiment is used as a material for yarn and / or film, the thermoplastic resin (A) is preferably a polyester-based resin, and it is more preferable to use polyethylene terephthalate and / or polybutylene terephthalate as the polyester-based resin.

[0022] Examples of polyamide resins used as the thermoplastic resin (A) include polyamide-6 (nylon-6), nylon-46, polyamide-66 (nylon-66), nylon-7, nylon-8, nylon-9, nylon-10, nylon-11, nylon-12, nylon-610, nylon-612, polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, polymetaxylene adipamide, polyxylylene sebacamide, nylon 6 / 66 copolymer, nylon 6 / 612, nylon MXD (m-xylylenediamine) 6, nylon 9T, nylon 10T, nylon 6T / 66 copolymer, nylon 6T / 6I copolymer, nylon 6T / M5T copolymer, nylon 6T / 12 copolymer, nylon 66 / 6T / 6I copolymer, nylon 6T / 6 copolymer, nylon 66 / 6I copolymer, nylon 66 / 6I / 6 copolymer, and the like.

[0023] When the thermoplastic resin composition produced by the production method of this embodiment is used as a material for yarn and / or film, and the thermoplastic resin (A) is a polyamide resin, it is preferable to use polyamide-6 and / or polyamide-66 as the polyamide resin.

[0024] In the manufacturing method of this embodiment, it is preferable to use one or more of the above thermoplastic resins (A) selected from polyethylene terephthalate, polybutylene terephthalate, polyamide-6, polycarbonate, and polyphenylene sulfide, which is a polyphenylene resin. This is because the thermoplastic resin composition containing the above resin can be suitably used for various applications and is industrially useful. In addition, the above resin has a sufficiently large specific gravity. For this reason, the thermoplastic resin composition produced by the manufacturing method of this embodiment using one or more of the above resins as the thermoplastic resin (A) has a better filler dispersion state.

[0025] The thermoplastic resin (A) is preferably in the form of pellets. When the thermoplastic resin (A) is in the form of pellets, the specific gravity of the thermoplastic resin (A) in the form of pellets is preferably 1 or more. When the thermoplastic resin (A) is in the form of pellets, the filler in the thermoplastic resin composition produced by the production method of this embodiment has a better dispersion state.

[0026] The thermoplastic resin (A) may be a virgin product, a recycled product, or a mixture of a virgin product and a recycled product. Examples of the recycled product include a molded product of a thermoplastic resin used as a product, a thermoplastic resin recovered from a resin molded product, and a recovered thermoplastic resin generated as a waste material in the manufacturing process of a product.

[0027] (Aqueous dispersion (B)) The water dispersion (B) may be any one that contains a filler and water as essential components. The water dispersion (B) is a dispersion of a filler in water. The water dispersion (B) is preferably one that is produced by dispersing a filler in water in advance, since the dispersion state is good. The filler may be inorganic particles made of an inorganic compound or organic particles made of an organic compound, and can be appropriately determined depending on the intended use of the thermoplastic resin composition, etc. The filler may be used alone or in combination of two or more kinds.

[0028] The inorganic particles used as the filler are not particularly limited as long as they do not impair the effects of the present invention, and examples thereof include particles made of metal oxides. Examples of metal oxides include oxides of metals such as titanium (Ti), silicon (Si), zinc (Zn), aluminum (Al), copper (Cu), iron (Fe), molybdenum (Mo), zirconia (Zr), tin (Sn), and indium (In). Specific examples of metal oxides include SiO2, TiO2, ZrO, CuO, Cu2O, CsWO3, Al2O3, SnO2, ITO (indium tin oxide), and ATO (antimony-doped tin oxide). Other examples of particles made of simple metals include gold (Au), silver (Ag), aluminum (Al), and copper (Cu) particles.

[0029] The organic particles used as a filler are not particularly limited as long as they do not impair the effects of the present invention. Examples of the organic particles include synthetic resin materials such as crosslinked styrene particles, crosslinked acrylic particles, crosslinked acrylic-styrene particles, melamine resins, and benzoguanamine resins; carbon-based materials such as carbon nanotubes, graphene, and carbon black; and biomass-based materials such as cellulose nanofibers.

[0030] The filler contained in the water dispersion (B) preferably has a particle size of 0.01 μm or more, more preferably 0.05 μm or more. When the particle size of the filler is 0.01 μm or more, the filler in the water dispersion (B) is less likely to aggregate. Therefore, the dispersion state of the filler in the thermoplastic resin composition produced by the production method of this embodiment is better.

[0031] The filler contained in the water dispersion (B) preferably has a particle size of 3 μm or less, more preferably 1 μm or less. When the particle size of the filler is 3 μm or less, the uniformity of the filler dispersion state in the thermoplastic resin composition can be prevented from decreasing due to the large particle size of the filler. Therefore, the filler dispersion state in the thermoplastic resin composition produced by the production method of this embodiment becomes better.

[0032] In this embodiment, the particle size of the filler contained in the water dispersion (B) is the D 50 The value is

[0033] The content of the filler in the material to be kneaded can be appropriately determined depending on the intended use of the thermoplastic resin composition as the final product. The mixed material preferably contains 0.01% by mass or more, more preferably 0.1% by mass or more, of the filler when the total mass of the thermoplastic resin (A) and the filler is taken as 100% by mass. When the filler content is 0.01% by mass or more, a thermoplastic resin composition is obtained in which the effect of including the filler is easily exhibited. When the total mass of the thermoplastic resin (A) and the filler is taken as 100 mass%, the content of the filler is preferably 50 mass% or less, and more preferably 10 mass% or less. When the content of the filler is 50 mass% or less, the filler can be prevented from interfering with the moldability of the thermoplastic resin composition.

[0034] The aqueous dispersion (B) may contain, in addition to the filler and water, for example, a water-soluble alcohol and / or a surfactant. Examples of the water-soluble alcohol include methanol, ethanol, isopropanol, polyvinyl alcohol, butanol, ethylene glycol, polyethylene glycol, glycerin, polyglycerin, etc. The water-soluble alcohol may be used alone or in combination of two or more kinds.

[0035] Examples of the surfactant include the compounds shown below. Glycerol fatty acid esters such as glyceryl monostearate (HLB (Hydrophile Lipophile Balance) value 4.0), self-emulsifying glyceryl monostearate (HLB value 6.0), and glyceryl monooleate (HLB value 2.5); Polyglyceryl-6 Polyricinoleate (HLB value 3.9), Diglyceryl Monostearate (HLB value 5.0), Diglyceryl Monooleate (HLB value 6.5), Diglyceryl Dioleate (HLB value 7.0), Diglyceryl Monoisostearate (HLB value 5.5), Tetraglyceryl Monostearate (HLB value 6.0), Tetraglyceryl Monooleate (HLB value 6.0), Decaglyceryl Tristearate (HLB value 7.5), Decaglyceryl Trioleate (HLB value 7.0), Decaglyceryl Pentastearate polyglycerin fatty acid esters such as glyceryl monolaurate (HLB value 3.5), hexaglyceryl monolaurate (HLB value 14.5), hexaglyceryl monomyristate (HLB value 11.0), decaglyceryl monolaurate (HLB value 15.5), decaglyceryl monomyristate (HLB value 14.0), decaglyceryl monostearate (HLB value 12.0), decaglyceryl monoisostearate (HLB value 12.0), decaglyceryl monooleate (HLB value 12.0), and decaglyceryl diisostearate (HLB value 10.0); Sorbitan fatty acid esters such as sorbitan monopalmitate (HLB value 6.7), sorbitan monostearate (HLB value 4.7), sorbitan sesquistearate (HLB value 4.2), sorbitan tristearate (HLB value 2.1), sorbitan monoisostearate (HLB value 5.0), sorbitan sesquiisostearate (HLB value 4.5), sorbitan monooleate (HLB value 4.3), and sorbitan sesquioleate (HLB value 3.7); POE(3) lauryl ether (HLB value 8.0), POE(5) lauryl ether (HLB value 10.0), POE(5) isocetyl ether (HLB value 8.0), POE(3) cetyl ether (HLB value 6.0), POE(5) cetyl ether (HLB value 8.0), POE(2) stearyl ether (HLB value 8.0), POE(5) stearyl ether (HLB value 8.0), POE(6) stearyl ether (HLB value 8.0), POE(5) isostearyl ether (HLB value 8.0), POE(2) oleyl ether (HLB value 7.5), P OE(3) oleyl ether (HLB value 6.0), POE(5) oleyl ether (HLB value 8.0), POE(5) octyldodecyl ether (HLB value 7.0), POE(5) behenyl ether (HLB value 7.0), POE(5) decyl tetradecyl ether (HLB value 6.0), POE(3) secondary alkyl ether (HLB value 8.0), POE(5) cholesteryl ether (HLB value 7.0), POE(4.2) lauryl ether (HLB value 11.5), POE(7) lauryl ether (HLB value 11.0), POE(9) lauryl ether (H LB value 14.5), POE (10) lauryl ether (HLB value 12.0), POE (12) lauryl ether (HLB value 13.0), POE (15) lauryl ether (HLB value 14.0), POE (20) lauryl ether (HLB value 15.0), POE (30) lauryl ether (HLB value 16.0), POE (50) lauryl ether (HLB value 17.0), POE (10) isocetyl ether (HLB value 11.0), POE (15) isocetyl ether (HLB value 13.0), POE (20) isocetyl ether (HLB value 14.0), PO E(25) isocetyl ether (HLB value 15.0), POE(5.5) cetyl ether (HLB value 10.5), POE(7) cetyl ether (HLB value 11.5), POE(10) cetyl ether (HLB value 13.5), POE(12) cetyl ether (HLB value 12.0), POE(15) cetyl ether (HLB value 15.5), POE(17) cetyl ether (HLB value 13.0), POE(20) cetyl ether (HLB value 17.0), POE(23) cetyl ether (HLB value 18.0), POE(8) stearyl ether (HLB value 10.0), POE(11) stearyl ether (HLB value 11.0), POE(15) stearyl ether (HLB value 12.0), POE(20) stearyl ether (HLB value 18.0), POE(25) stearyl ether (HLB value 14.0), POE(30) stearyl ether (HLB value 15.0), POE(40) stearyl ether (HLB value 16.0), POE(10) isostearyl ether (HLB value 11.0), POE(15) isostearyl ether (HLB value 12.0), POE(20) isostearyl ether (HLB value 13.0), POE(25) isostearyl ether (HLB value 14.0), POE(3) oleyl ether (HLB value 6.0), POE(7) oleyl ether (HLB value 10.5), POE(8) oleyl ether (HLB value 10.0), POE(10) oleyl ether (HLB value 14.5), POE(12) oleyl ether (HLB value 11.0), POE(15) oleyl ether (HLB value 16.0), POE(20) oleyl ether (HLB value 17.0), POE(23) oleyl ether (HLB value 14.0), POE(50 ) Oleyl ether (HLB value 18.0), POE (10) Octyldodecyl ether (HLB value 10.0), POE (16) Octyldodecyl ether (HLB value 12.0), POE (20) Octyldodecyl ether (HLB value 13.0), POE (25) Octyldodecyl ether (HLB value 14.0), POE (25) Octyldodecyl ether (HLB value 14.0), POE (10) Behenyl ether (HLB value 10.0), POE (20) Behenyl ether (HLB value 16.5), POE (30) Behenyl ether (HLB value 18. 0), POE(15) decyl tetradecyl ether (HLB value 11.0), POE(20) decyl tetradecyl ether (HLB value 12.0), POE(25) decyl tetradecyl ether (HLB value 13.0), POE(4) (C12-15) alkyl ether (HLB value 10.5), POE(8) (C9-11) alkyl ether (HLB: 13.9), POE(10) (C12-15) alkyl ether (HLB value 15.5), POE(5) secondary alkyl ether (HLB value 10.5), POE(7) secondary alkyl ether (HLB value 12.0), POE(10) cholesteryl ether (HLB value 10.0), POE(15) cholesteryl ether (HLB value 11.0), POE(20) cholesteryl ether (HLB value 12.0), POE(24) cholesteryl ether (HLB value 13.0), POE(30) cholesteryl ether (HLB value 14.0) and other polyoxyethylene alkyl ethers; POE(2) laurylamine (HLB value 5.2), POE(2) stearylamine (HLB value 5.1), POE(3) tallow propylene diamine (HLB value 5.9), N-bis-N-cyclohexylamine (HLB value 4.8), POE(2) metaxylene diamine (HLB value 7.9), POE(5) laurylamine (HLB value 10.4), POE(7) laurylamine (HLB value 11.5), value 12.1), POE(10) laurylamine (HLB value 13.6), POE(30) laurylamine (HLB value 17.5), POE(7) ethylene tallowamine (HLB value 11.0), POE(8) ethylene tallowamine (HLB value 11.9), POE(10) ethylene tallowamine (HLB value 12.7), POE(13.5) ethylene tallowamine (HLB value 11.0), POE( 20) Ethylene tallow amine (HLB value 15.5), POE(30) Ethylene tallow amine (HLB value 16.7), POE(40) Ethylene tallow amine (HLB value 17.4), POE(7) Stearylamine (HLB value 10.7), POE(10) Stearylamine (HLB value 12.8), POE(15) Stearylamine (HLB value 14.3), POE(20) Stearylamine (HLB value 15.3), POE(30)stearylamine (HLB value 16.7), POE(45)stearylamine (HLB value 17.6), POE(15)tallow propylenediamine (HLB value 13.4), POE(50)stearylpropylenediamine (HLB value 17.4), POE(4)metaxylendiamine (HLB value 11.3), and other polyoxyethylene alkylamines; Polyoxyethylene alkylamides such as POE(50) stearylamide (HLB value 17.8).

[0036] In the above descriptions of compounds used as surfactants, "POE" means polyoxyethylene. The notation of the compounds used as the above-mentioned surfactants will be explained using, for example, "POE(8)(C9-11) alkyl ether." "(8)" refers to m in the following general formula (1). Also, "(C9-11) alkyl" refers to an alkyl mixture with 9 to 11 carbon atoms. R-(CH2CH2O) m -H (1)

[0037] The surfactant contained in the aqueous dispersion (B) may be one type only, or may be two or more types. The surfactant can be appropriately determined depending on the types of the thermoplastic resin (A) and the filler contained in the aqueous dispersion (B).

[0038] The content of the surfactant contained in the water dispersion (B) can be appropriately determined depending on the type of the thermoplastic resin (A) and the type of the filler contained in the water dispersion (B), etc. The content of the surfactant contained in the water dispersion (B) is preferably 10 parts by mass or more per 100 parts by mass of the filler contained in the water dispersion (B). The content of the surfactant contained in the water dispersion (B) is preferably 200 parts by mass or less per 100 parts by mass of the filler contained in the water dispersion (B).

[0039] The content of the surfactant contained in the aqueous dispersion (B) of the kneaded material is preferably 0.01% by mass or more when the total mass of the thermoplastic resin (A) and the filler is taken as 100% by mass. When the content of the surfactant is 0.01% by mass or more, the dispersion state of the filler in the thermoplastic resin composition produced by the production method of this embodiment becomes better due to the dispersibility improving function of the surfactant.

[0040] When the total mass of the thermoplastic resin (A) and the filler is taken as 100 mass%, the content of the surfactant contained in the aqueous dispersion (B) is preferably 40 mass% or less. When the content of the surfactant is 40 mass% or less, the contents of the thermoplastic resin (A) and the filler in the kneaded material can be easily ensured.

[0041] [Other ingredients] The material to be kneaded may contain other components in addition to the thermoplastic resin (A) and the aqueous dispersion (B) within the scope of the essential functions thereof, such as antioxidants, ultraviolet absorbers, colorants, pigments, dyes, foaming agents, lubricants, flame retardants, fillers, coupling agents, etc. In this embodiment, when a component functioning as a filler is used as the other component, the component functioning as a filler used as the other component is supplied together with the thermoplastic resin (A) from the first supply means described later. In this embodiment, all components functioning as a filler supplied as the aqueous dispersion (B) from the second supply means described later are regarded as fillers contained in the aqueous dispersion (B) and are not regarded as other components. In this embodiment, when the material to be kneaded contains other components, the content of the other components is preferably 10 mass% or less, and more preferably 5 mass% or less, when the total mass of the thermoplastic resin (A) and the filler contained in the aqueous dispersion (B) is 100 mass%.

[0042] [Twin-screw kneading extruder] In the kneading step in the production method of the present embodiment, a twin-screw kneading extruder is used. Fig. 1 is a diagram showing an example of a twin-screw kneading extruder used in the production method of a thermoplastic resin composition of the present embodiment, and is an explanatory diagram for explaining a cylinder 10 of the twin-screw kneading extruder. Fig. 2 is a cross-sectional view of the cylinder 10 shown in Fig. 1 along the line AA'. In this embodiment, the cylinder 10 can be, for example, a barrel having a generally rectangular cross-sectional shape as shown in Figures 1 and 2, and having a through hole in which two screws 51 and 52 are housed, which is formed by connecting multiple barrels.

[0043] In Fig. 1, the symbol L indicates the length from the upstream end 11 to the downstream end 12 of the cylinder 10. When the cylinder 10 is formed by connecting multiple barrels, the upstream end 11 is the upstream end face of the barrel located most upstream. When the cylinder 10 is formed by connecting multiple barrels, the downstream end 12 is the downstream end face of the barrel located most downstream.

[0044] 1 and 2, the symbol D indicates the inner diameter of the cylinder 10. In this embodiment, the inner diameter D of the cylinder 10 means the inner diameter D of the cylinder 10 in a direction that passes through one of the central axes of the two screws 51, 52 and is perpendicular to a straight line connecting the central axes of the two screws 51, 52 in a cross-sectional view as shown in FIG.

[0045] As shown in Figures 1 and 2, two screws 51 and 52 are housed in the cylinder 10. The screws 51 and 52 knead the material to be kneaded while transporting it from the upstream end 11 to the downstream end 12 of the cylinder 10. It is preferable that a known die is installed at the downstream end 12.

[0046] Any screw that can be used in a known twin-screw kneading extruder can be used as the screws 51 and 52. The type of each screw 51 and 52 can be appropriately determined depending on the value of L / D, which is the ratio of the length L of the cylinder 10 to the inner diameter D, the type of material to be kneaded that is melt-mixed by the twin-screw kneading extruder, the predetermined position and the predetermined length of the full-filling region 41, and the like.

[0047] The cylinder 10 shown in FIG. 1 has a first supplying means 21, a second supplying means 22, a first discharging means 31, second discharging means 32, 33, and a heating means (not shown). The first supplying means 21 supplies a solid material into the cylinder 10. The first supplying means 21 is provided in the vicinity of the upstream end 11 of the cylinder 10. The second supply means 22 supplies the liquid material into the cylinder 10. The second supply means 22 is provided at a position where a distance 22L from the upstream end 11 of the cylinder 10 is 60% or less of the length of the cylinder 10.

[0048] The first discharge means 31 and the second discharge means 32, 33 are for discharging the gas in the cylinder 10. The first discharge means 31 is provided on the upstream side (upstream end 11 side) of the second supply means 22 as shown in FIG. 1. The second discharge means 32, 33 are provided on the downstream side (downstream end 12 side) of the full filling region 41 as shown in FIG. 1. One or more of the second discharge means 32, 33 are provided as necessary. Whether or not to provide the second discharge means 32, 33 and the number of the second discharge means 32, 33 can be appropriately determined according to the length of the cylinder 10 downstream of the full filling region 41, and two may be provided as in the example shown in FIG. 1, or one or three or more may be provided, or none may be provided.

[0049] The first supply means 21, the second supply means 22, the first discharge means 31, and the second discharge means 32 and 33 of the cylinder 10 shown in Fig. 1 may be any of those used in known extruders. The first discharge means 31 is provided separately from the first supply means 21, as shown in Fig. 1.

[0050] Moreover, the first discharge means 31 and the second discharge means 32, 33 may all be means for reducing the pressure inside the cylinder 10 (reducing the pressure inside the cylinder 10). In particular, in order to efficiently discharge the gas inside the cylinder 10, it is preferable that the second discharge means 32, 33 be means for reducing the pressure inside the cylinder 10.

[0051] The heating means heats a predetermined position of the cylinder 10 to a predetermined temperature to melt the thermoplastic resin (A), and may be one used in known extruders. Conditions such as the installation position and heating temperature of the heating means are appropriately determined depending on the length L and diameter D of the cylinder 10, the type of thermoplastic resin (A) and the type of filler contained in the water dispersion (B), the content of the thermoplastic resin (A) in the material to be kneaded, the positions of the first supply means 21 and the second supply means 22, the supply speed of the material to be kneaded, and the like.

[0052] In the kneading step in the manufacturing method of this embodiment, a pellet-shaped thermoplastic resin (A) as the material to be kneaded is supplied from the first supply means 21, and an aqueous dispersion (B) as the material to be kneaded is supplied from the second supply means 22. The supply speed of the thermoplastic resin (A) supplied from the first supply means 21 and the supply speed of the aqueous dispersion (B) supplied from the second supply means 22 can be appropriately determined depending on the ratio of the thermoplastic resin (A) and the aqueous dispersion (B) in the material to be kneaded, the rotation speed of the screws 51 and 52, the value of L / D which is the ratio of the length L to the inner diameter D of the cylinder 10, and the like.

[0053] In the kneading step in the production method of this embodiment, when the material to be kneaded contains other components in addition to the thermoplastic resin (A) and the aqueous dispersion (B), the other components may be supplied from the first supply means 21 together with the thermoplastic resin (A), or may be supplied from the second supply means 22 together with the aqueous dispersion (B), or may be supplied from both the first supply means 21 and the second supply means 22. The other components may be mixed with the thermoplastic resin (A) in advance and then supplied from the first supply means 21 together with the thermoplastic resin (A).

[0054] It is preferable that the thermoplastic resin (A) and the water dispersion (B) are each continuously supplied into the cylinder 10. Then, the two screws 51, 52 are continuously rotated to knead and convey the materials to be kneaded, which are composed of the thermoplastic resin (A) and the water dispersion (B), while the materials to be kneaded are heated by the heating means to melt the thermoplastic resin (A).

[0055] At this time, in this embodiment, gas (bubbles) such as water vapor derived from the water in the water dispersion (B) is generated from the material to be kneaded. The gas generated in the mixing material fluctuates the pressure in the cylinder 10, making the mixing state of the mixing material uneven. In addition, when the gas is generated from the mixing material, the filler present in the mixing material together with the water in the water dispersion (B) may aggregate, generating coarse particles.

[0056] In this embodiment, the gas generated in the material to be kneaded moves in the cylinder 10 while being kneaded together with the liquid and solid materials to be kneaded, and is discharged from the first discharge means 31 and the second discharge means 32, 33. Therefore, in the kneading process, the generation of gas from the material to be kneaded in the cylinder 10 can be effectively suppressed from interfering with the melt mixing of the material to be kneaded. Therefore, in this embodiment, the pressure fluctuation in the cylinder 10 caused by the gas generated in the material to be kneaded is suppressed, and the material to be kneaded is melt mixed uniformly without unevenness. In addition, since the gas is generated from the material to be kneaded that is melt mixed uniformly without unevenness, the aggregation of the filler derived from the water dispersion (B) in the kneading process can be suppressed, and the generation of coarse particles is suppressed. Therefore, a thermoplastic resin composition with a good filler dispersion state is discharged from the downstream end 12.

[0057] In the method for producing a thermoplastic resin composition of this embodiment, a twin-screw kneading extruder is used in which the distance 22L of the second supplying means 22 from the upstream end 11 of the cylinder 10 is 60% or less of the length of the cylinder 10. Therefore, in the kneading step, the time during which the thermoplastic resin (A) supplied from the first supplying means 21 is kneaded with the aqueous dispersion (B) supplied from the second supplying means 22 in the cylinder 10 becomes sufficiently long. As a result, a thermoplastic resin composition in which the filler is well dispersed is discharged from the downstream end 12.

[0058] In this embodiment, the distance 22L from the upstream end 11 of the cylinder 10 of the second supply means 22 means the distance 22L between the upstream end 11 and a cross section passing through the center of the connecting surface of the supply piping of the second supply means 22 with the wall surface of the cylinder 10.

[0059] The distance 22L of the second supply means 22 from the upstream end 11 of the cylinder 10 is preferably 55% or less, and more preferably 50% or less, of the length of the cylinder 10. This is because the thermoplastic resin (A) and the aqueous dispersion (B) are kneaded for a longer period of time in the cylinder 10, making it easier to obtain a thermoplastic resin composition in which the filler is better dispersed.

[0060] As shown in FIG. 1, the distance 22L of the second supply means 22 from the upstream end 11 of the cylinder 10 is longer than the distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10. That is, the second supply means 22 is disposed downstream of the first discharge means 31. Therefore, in the kneading process, gas (bubbles) generated by melt-mixing the thermoplastic resin (A) and the aqueous dispersion (B) can be discharged upstream of the position where the thermoplastic resin (A) and the aqueous dispersion (B) come into contact with each other. As a result, it is possible to effectively prevent the gas generated from the material to be kneaded in the cylinder 10 from interfering with the melt-mixing of the material to be kneaded.

[0061] Moreover, the distance 22L from the upstream end 11 of the cylinder 10 to the second supplying means 22 is preferably at least 5% longer than the length of the cylinder 10, and more preferably at least 10% longer than the distance 31L from the upstream end 11 of the cylinder 10 to the first discharging means 31. This is because the water dispersion (B), which is the material to be kneaded and is supplied from the second supplying means 22, can be prevented from being discharged from the first discharging means 31.

[0062] The difference between the distance 22L of the second supply means 22 from the upstream end 11 of the cylinder 10 and the distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10 is preferably 30% or less of the length of the cylinder 10, more preferably 20% or less. In this case, the time that the gas generated by melt-mixing the thermoplastic resin (A) and the aqueous dispersion (B) in the kneading step remains in the cylinder 10 upstream of the second supply means 22 is shortened, and the gas in the cylinder 10 can be efficiently discharged. Therefore, it is possible to effectively prevent the gas generated from the material to be kneaded in the cylinder 10 from interfering with the melt-mixing of the material to be kneaded.

[0063] In the method for producing a thermoplastic resin composition of this embodiment, a twin-screw kneading extruder is used in which the distance 31L from the upstream end 11 of the cylinder 10 to the first discharge means 31 is 40% or less of the length L of the cylinder 10. Therefore, in the kneading process, gas generated by melt-mixing the material to be kneaded is quickly discharged from inside the cylinder 10 upstream of the second supply means 22. As a result, it is possible to effectively prevent the gas generated from the material to be kneaded in the cylinder 10 from interfering with the melt-mixing of the material to be kneaded.

[0064] In this embodiment, the distance 31L from the upstream end 11 of the cylinder 10 to the first discharge means 31 means the distance 31L between the upstream end 11 and a cross section passing through the center of the connecting surface of the discharge piping of the first discharge means 31 with the wall surface of the cylinder 10.

[0065] The distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10 is 40% or less of the length L of the cylinder 10. In this case, the second supply means 22 can be disposed at a more upstream position, and the distance over which the thermoplastic resin (A) and the aqueous dispersion (B) are kneaded in the cylinder 10 can be increased, thereby lengthening the kneading time. Therefore, it becomes easier to obtain a thermoplastic resin composition in which the filler is more favorably dispersed. The distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10 is preferably 30% or less of the length L of the cylinder 10.

[0066] The distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10 is preferably 1% or more, more preferably 5% or more, of the length L of the cylinder 10. This is because it is possible to prevent gas generated in the material to be kneaded from leaking from the upstream end 11 to the drive part side of the screws 51 and 52 without being discharged from the first discharge means 31.

[0067] In the method for producing a thermoplastic resin composition of this embodiment, in the kneading step, a full-filled region 41 in which the material to be kneaded is filled in a direction perpendicular to the length direction of the cylinder 10 is formed from a position downstream of the second supply means 22 in the cylinder 10 by 10% or more of the length L of the cylinder 10 toward the downstream side. That is, the full-filled region 41 is formed by determining the distance 41L of the full-filled region 41 from the upstream end 11 of the cylinder 10 so that the distance between the upstream position of the full-filled region 41 and the second supply means 22 is 10% or more of the length L of the cylinder 10.

[0068] The full-filled region 41 can be formed in the cylinder 10 at a predetermined position and with a predetermined length by a known method. Specifically, the full-filled region 41 can be formed in the cylinder 10 at a predetermined position and with a predetermined length by appropriately adjusting conditions such as the shape and rotation speed of the screws 51 and 52, the supply speed and supply amount of the material to be kneaded, and the melt viscosity of the material to be kneaded.

[0069] In this embodiment, at least a part of the gas generated from the mixing material is discharged from the upstream side of the second supplying means 22 by the first discharge means 31 arranged upstream of the second supplying means 22. Therefore, the mixing material melt-mixed in the full-filling region 41 has a low gas content. As a result, in the full-filling region 41, the mixing material is easily mixed uniformly without unevenness, and the generation of coarse particles due to the aggregation of the filler derived from the water dispersion (B) is suppressed. Therefore, a thermoplastic resin composition with a good filler dispersion state is obtained.

[0070] In this embodiment, the full-filled region 41 is formed so that the distance between the upstream position of the full-filled region 41 and the second supplying means 22 is 10% or more of the length L of the cylinder 10, so that the full-filled region 41 can be easily formed. In addition, it is possible to prevent a situation in which the second supplying means 22 is clogged during the kneading step and the aqueous dispersion (B) cannot be supplied due to the distance between the second supplying means 22 and the full-filled region 41 being too close. Therefore, a thermoplastic resin composition with a good filler dispersion state can be produced continuously and efficiently.

[0071] In this embodiment, the full-filled region 41 is formed so that the distance between the upstream position of the full-filled region 41 and the second supply means 22 is 10% or more of the length L of the cylinder 10, so that the distance in the cylinder 10 where the thermoplastic resin (A) and the aqueous dispersion (B) are kneaded can be sufficiently secured, and a thermoplastic resin composition with a good filler dispersion state can be obtained. It is preferable to form the full-filled region 41 so that the distance between the upstream position of the full-filled region 41 and the second supply means 22 is 15% or more of the length L of the cylinder 10, and it is more preferable to form the full-filled region 41 so that the distance is 20% or more of the length L of the cylinder 10. This is because a thermoplastic resin composition with a better filler dispersion state can be obtained.

[0072] In the method for producing a thermoplastic resin composition of this embodiment, a twin-screw kneading extruder having two second discharge means 32, 33 for discharging the gas in the cylinder 10 is used at a position downstream of the full-filling region 41. Then, in the kneading step, the gas in the cylinder 10 is discharged from the second discharge means 32, 33 to reduce the pressure in the cylinder 10. Therefore, the gas remaining in the material to be kneaded that has been melt-mixed in the full-filling region 41 can be efficiently discharged from the two second discharge means 32, 33. As a result, the gas remaining in the material to be kneaded is less likely to interfere with the melt-mixing of the material to be kneaded, and a thermoplastic resin composition with a better dispersion state of the filler can be obtained.

[0073] In the method for producing a thermoplastic resin composition of this embodiment, a twin-screw kneading extruder is used in which the value of L / D, which is the ratio of the length L to the inner diameter D of the cylinder 10, is 30 or more. Therefore, in the kneading step, the distance in the cylinder 10 where the materials to be kneaded are melt-mixed can be sufficiently secured, and the materials to be kneaded are melt-mixed in the cylinder 10 for a sufficiently long time. Therefore, the thermoplastic resin (A) in the materials to be kneaded can be sufficiently melted in the cylinder 10, and the thermoplastic resin (A) and the water dispersion (B) can be sufficiently kneaded in the cylinder 10. As a result, by performing the kneading step of this embodiment, a thermoplastic resin composition in which the filler is well dispersed is discharged from the downstream end 12 of the cylinder 10.

[0074] The L / D value of the cylinder 10 is preferably 40 or more, and more preferably 45 or more. This is because the kneading step makes it easier to obtain a thermoplastic resin composition in which the filler is more favorably dispersed. The L / D value of the cylinder 10 is preferably 100 or less, and more preferably 90 or less. When the L / D value of the cylinder 10 is 100 or less, this is because the aggregation of the filler caused by excessive kneading of the material to be kneaded can be suppressed.

[0075] In the method for producing a thermoplastic resin composition of this embodiment, a twin-screw kneading extruder shown in Fig. 1 is used to perform a kneading process in which a material to be kneaded containing a thermoplastic resin (A) having a specific gravity of 1 or more and an aqueous dispersion (B) containing a filler are melt-mixed. In this embodiment, gas generated in the material to be kneaded in the kneading process moves inside the cylinder 10 while being kneaded together with the liquid and solid materials to be kneaded, and is discharged from the first discharge means 31 and the second discharge means 32 and 33. As a result, it is possible to effectively prevent gas from being generated from the material to be kneaded in the cylinder 10 from interfering with the melt mixing of the material to be kneaded, and a thermoplastic resin composition in which the filler is well dispersed can be produced.

[0076] The thermoplastic resin composition produced by the method for producing a thermoplastic resin composition of this embodiment can be pelletized by a known method. Specifically, the method for pelletizing the thermoplastic resin composition can be, for example, a method in which a known die is provided at the downstream end 12 of the cylinder 10 of the twin-screw kneading extruder used in the method for producing a thermoplastic resin composition of this embodiment, the thermoplastic resin composition is extruded through the known die to form a cylindrical strand, and the strand is cut by a known cutting means such as a pelletizer. EXAMPLES

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0078] [Examples 1 to 9, Comparative Examples 1 to 4] The thermoplastic resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4 were produced by performing a kneading process in which the materials to be kneaded were melt-mixed using a twin-screw kneading extruder shown in Figures 1 and 2 having a cylinder 10 with an inner diameter D shown in Table 1 or Table 2 and an L / D value, which is the ratio of the length L to the inner diameter D, shown in Table 1 or Table 2.

[0079] As the twin-screw kneading extruder, one having a first supply means 21, a second supply means 22, a first discharge means 31, a second discharge means 32 (upstream side), a second discharge means 33 (downstream side), and a heating means (not shown) was used, as shown in Fig. 1. As the second discharge means 32, 33, one for reducing the pressure inside the cylinder 10 was used. Table 1 or Table 2 shows the ratio of the distance from the upstream end 11 of the cylinder 10 to the length L of the cylinder 10 for the first supply means 21, the second supply means 22, the first discharge means 31, the second discharge means 32 (upstream side), and the second discharge means 33 (downstream side), respectively.

[0080] As the materials to be kneaded, a thermoplastic resin (A) in pellet form and an aqueous dispersion (B) shown in Table 1 or Table 2 were used. As the aqueous dispersion (B), one containing a filler shown in Table 1 or Table 2 and, if necessary, a surfactant shown in Table 1 or Table 2 was used. As the surfactant, polyoxyethylene lauryl ether (POE (5) lauryl ether (HLB value 10.0)) was used, and one containing it at the ratio (parts by mass) shown in Table 1 or Table 2 per 100 parts by mass of the filler was used.

[0081] In the kneading process, the thermoplastic resin (A) was continuously supplied from the first supply means, and the aqueous dispersion (B) was continuously supplied from the second supply means, so that the filler content in the kneaded material in the cylinder 10 (the filler content when the total mass of the thermoplastic resin (A) and the filler is taken as 100 mass%) was set to the content shown in Table 1 or Table 2.

[0082] In the kneading process, the two screws 51, 52 were rotated continuously to knead and transport the materials to be kneaded, while the entire cylinder 10 was heated by the heating means to the heating temperature shown in Table 1 or Table 2, thereby heating the materials to be kneaded to melt the thermoplastic resin (A), and continuously discharging the gas generated from the materials to be kneaded from the first discharge means 31, the second discharge means 32 (upstream side) and the second discharge means 33 (downstream side).

[0083] In the kneading process, the shapes of the two screws 51, 52 were adjusted according to the position in the length direction of the cylinder 10, thereby forming the full-filled region 41 at a predetermined position. Specifically, a screw top with a forward twist, a screw top without a twist, and a screw top with a reverse twist were prepared as parts (tops) for forming the two screws 51, 52. Then, the two screws 51, 52 were formed with these parts arranged at predetermined positions. The obtained two screws 51, 52 were housed in the cylinder 10, and the parts having appropriate shapes were arranged at appropriate positions in the length direction of the cylinder 10. As a result, the full-filled region 41 was arranged at a predetermined position.

[0084] The ratio of the distance from the upstream end 11 of the cylinder 10 to the length L of the cylinder 10 to the upstream position of the full filling region 41 is shown in Table 1 or Table 2. Also, the difference (full filling region-second supply means) between the full filling region 41 and the second supply means 22 in the ratio of the distance from the upstream end 11 of the cylinder 10 to the length L of the cylinder 10 is shown in Table 1 and Table 2.

[0085] The thermoplastic resin composition thus obtained was extruded from a die installed at the downstream end 12 of the twin-screw kneading extruder to form a cylindrical strand, which was then cut using a pelletizer. In this way, the thermoplastic resin composition was pelletized to form the pelletized thermoplastic resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4.

[0086] However, in Comparative Example 1, a large amount of the thermoplastic resin (A) supplied from the first supply means 21 overflowed from the first discharge means 31, and therefore a pellet-shaped thermoplastic resin composition could not be produced. In addition, in Comparative Example 2, although a pellet-shaped thermoplastic resin composition could be produced, strands could not be stably formed, and the pellet-shaped thermoplastic resin composition could not be quantitatively produced.

[0087] In Comparative Example 3, the second supply means 22 was clogged by carrying out the kneading step, and the aqueous dispersion (B) could not be supplied, and therefore a pellet-shaped thermoplastic resin composition could not be produced. In addition, in Comparative Example 4, although a pellet-shaped thermoplastic resin composition could be produced, strands could not be stably formed, and the pellet-shaped thermoplastic resin composition could not be quantitatively produced.

[0088] The pellet-shaped thermoplastic resin compositions of Examples 1 to 9, Comparative Example 2, and Comparative Example 4 obtained by the above-mentioned production methods were subjected to the evaluation of aggregates and dispersion state by the methods described below. The results are shown in Table 1 or Table 2.

[0089] [Table 1]

[0090] [Table 2]

[0091] The thermoplastic resin (A) and the water dispersion (B) in Tables 1 and 2 are as follows. "Thermoplastic resin (A)" PET 1.41 (Polyethylene terephthalate resin (Unitika: SA-1206) specific gravity 1.41) PBT 1.31 (Polybutylene terephthalate resin (Mitsubishi Engineering Plastics: NOVADURAN 5008) specific gravity 1.31) PA6 1.14 (Polyamide-6 (UBE NYLON 1013B) specific gravity 1.41) PPS 1.38 (Polyarylene sulfide (DIC Corporation: DIC.PPS MA-510) specific gravity 1.38) PC 1.19 (Polycarbonate (Mitsubishi Engineering Plastics: Iupilon S-3001) specific gravity 1.19) PP 0.90 (Polypropylene (Prime Polymer: Y-2000G) specific gravity 0.90)

[0092] "Water dispersion (B)" Zinc oxide 40% by mass (Zinc oxide particles with a particle size of 0.1 μm are contained in water at a concentration of 40% by mass.) Organic particles 10% by mass (organic particles made of cross-linked acrylic-styrene particles with a particle size of 0.1 μm are contained in water at a concentration of 10% by mass)

[0093] <Aggregate evaluation> A single-screw extruder having a cylinder with an inner diameter of 25 mm and a wire mesh with a mesh size of 10 μm attached to the tip of the cylinder was prepared. Using this single-screw extruder, 1.5 kg of each of the pellet-shaped thermoplastic resin compositions of Examples 1 to 9, Comparative Example 2, and Comparative Example 4 was heated to 300° C. and extruded.

[0094] The difference in pressure applied to the wire netting attached to the tip of the cylinder (pressure inside the tip of the cylinder) between the time when 500 g of the thermoplastic resin composition had been completely extruded and the time when 1.5 kg of the thermoplastic resin composition had been completely extruded was determined and evaluated according to the following criteria. The pressure applied to the wire netting was measured using a pressure gauge (manufactured by Dynisco) installed on the wire netting. The smaller the difference in pressure (pressure inside the tip of the cylinder) applied to the wire mesh at the above time point, the better the dispersion of the filler in the thermoplastic resin composition and the fewer the aggregates. If the dispersion state of the filler in the thermoplastic resin composition is poor and coarse particles (aggregates) formed by agglomeration of the filler derived from the water dispersion (B) are present in the thermoplastic resin composition, the wire mesh will become clogged with an increase in the amount of the extruded thermoplastic resin composition.

[0095] [Evaluation Criteria] ◎: Less than 1.0 MPa (very good). ○: 1.0 MPa or more, less than 3.0 MPa (good). △: 3.0 MPa or more, less than 5.0 MPa (practical). ×: 5.0 MPa or more (not practical).

[0096] <Dispersion state evaluation> The pellet-shaped thermoplastic resin compositions of Examples 1 to 9 and Comparative Examples 2 and 4 were each cut using a microtome to expose the cross section. The exposed cross section was observed using a scanning electron microscope, and the proportion of particles exceeding 3 μm among the number of particles present within a square area of ​​100 μm in length and 100 μm in width was calculated and evaluated according to the following evaluation criteria.

[0097] [Evaluation Criteria] ◎: Less than 0.1% (very good). ○: 0.1% or more, less than 1% (good). △: 1% or more, less than 5% (practical). ×: 5% or more (not practical).

[0098] As shown in Table 1, the pellet-shaped thermoplastic resin compositions of Examples 1 to 9 were all evaluated for aggregates and dispersion state as ◎ (very good) or ○ (good), confirming that the filler had a good dispersion state.

[0099] In contrast, as shown in Table 2, the pellet-shaped thermoplastic resin compositions of Comparative Examples 2 and 4 were evaluated as x (not suitable for practical use) in the aggregate evaluation and dispersion state evaluation. This is presumably because in Comparative Example 2, the value of L / D, which is the ratio of the length L to the inner diameter D of the cylinder 10, is small and the distance 22L of the second supply means 22 from the upstream end 11 of the cylinder 10 is long, so that the time during the kneading process for the kneaded material consisting of the thermoplastic resin (A) and the aqueous dispersion (B) to be kneaded within the cylinder 10 was insufficient.

[0100] In Comparative Example 4, the distance 22L of the second supply means 22 from the upstream end 11 of the cylinder 10 is shorter than the distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10. Moreover, in Comparative Example 4, the distance 31L of the first discharge means 31 from the upstream end 11 of the cylinder 10 is more than 40% of the length L of the cylinder 10. For this reason, it is presumed that the thermoplastic resin (A) and the aqueous dispersion (B) overflowed from the first discharge means 31 in the kneading step, hindering the melt mixing of the materials to be kneaded, and the aggregate evaluation and dispersion state evaluation of the pellet-shaped thermoplastic resin composition were × (not practical). [Explanation of symbols]

[0101] 10: cylinder, 11: upstream end portion, 12: downstream end portion, 21: first supply means, 22: second supply means, 31: first discharge means, 32, 33: second discharge means, 41: full-fill region.

Claims

1. The cylinder has two screws housed therein, and has a ratio of length L to inner diameter L, that is, L / D, of 30 or more; The cylinder is provided with a first supplying means for supplying a solid material into the cylinder, a second supplying means for supplying a liquid material into the cylinder, a first discharging means for discharging a gas in the cylinder, and a heating means for heating the inside of the cylinder; a distance of the second supply means from an upstream end of the cylinder to the upstream end of the cylinder is 60% or less of a length L of the cylinder; The distance of the first discharge means from the upstream end of the cylinder is 40% or less of the length L of the cylinder, Using a twin-screw kneading extruder in which the distance from the upstream end of the cylinder of the second supplying means is longer than the distance from the upstream end of the cylinder of the first discharging means, The method includes a kneading step of melt-mixing a material to be kneaded, the material including a thermoplastic resin (A) having a specific gravity of 1 or more and an aqueous dispersion (B) containing a filler, In the kneading step, the thermoplastic resin (A) is supplied from the first supply means, and the aqueous dispersion (B) is supplied from the second supply means; While rotating the two screws to knead and convey the material to be kneaded, the material to be kneaded is heated by the heating means to melt the thermoplastic resin (A) and gas generated from the material to be kneaded is discharged from the first discharge means; A method for producing a thermoplastic resin composition, comprising forming a fully filled region in the cylinder, the region being filled with the material to be kneaded in a direction perpendicular to the longitudinal direction of the cylinder, from a position in the cylinder that is at least 10% downstream of the second supply means and extending downstream along the length of the cylinder.

2. The method for producing a thermoplastic resin composition according to claim 1 , wherein the thermoplastic resin (A) is supplied in the form of pellets from the first supply means.

3. The method for producing a thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (A) is one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyamide-6, polyphenylene sulfide, and polycarbonate.

4. The method for producing a thermoplastic resin composition according to claim 1, wherein the particle size of the filler is 0.01 μm to 3 μm.

5. The method for producing a thermoplastic resin composition according to claim 1 , wherein the filler comprises inorganic particles and / or organic particles.

6. the cylinder has one or more second exhaust means downstream of the full-filling region for exhausting gas from within the cylinder; The method for producing a thermoplastic resin composition according to claim 1 , wherein in the kneading step, the gas in the cylinder is discharged from the second discharge means to reduce the pressure in the cylinder.

7. The method for producing a thermoplastic resin composition according to claim 1 , wherein the aqueous dispersion (B) contains a surfactant.

8. The method for producing a thermoplastic resin composition according to claim 1, wherein the content of the filler in the kneaded material is 0.01% by mass to 50% by mass when the total mass of the thermoplastic resin (A) and the filler is 100% by mass.

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