JP2019172828A - Styrene resin composition, and manufacturing method of expandable styrene resin particle - Google Patents

Abstract

To provide a styrene resin composition capable of providing a styrene resin foam molded body, having high expansion ratio, low heat conductivity, i.e. high heat insulation performance, and a manufacturing method of an expandable styrene resin particle.SOLUTION: There is provided a manufacturing method of a styrene resin composition including a process for supplying a styrene resin and carbon to a twin screw extruder and melting and mixing them, and Q/N of the twin screw extruder is set in a range of the following formula in a process for melting and mixing:Q/N≤8.0×10×D, wherein Q represents twin screw extruder extrusion amount (kg/hr), N represents screw rotation number (rpm), and D represents twin screw extruder barrel inner diameter (mm).SELECTED DRAWING: None

Description

  The present invention relates to a styrene resin composition and a method for producing expandable styrene resin particles.

  A styrene resin foam molded article obtained by using expandable styrene resin particles is a well-balanced foam having lightness, heat insulation, buffering properties, and the like. It is widely used as a heat insulating material for materials and houses. In particular, in recent years, in connection with various problems such as global warming, energy saving is being aimed at by improving the heat insulation of buildings such as houses, and the demand for styrene-based resin foam moldings is expected to increase.

  However, since the styrene resin foam molding is in a competitive market with other materials such as glass wool as a heat insulating material, thorough cost reduction is required in the production of the styrene resin foam molding. The styrenic resin foam molded article has a higher thermal conductivity and deteriorates the heat insulation property as the foaming ratio increases. Therefore, it is desired to lower the thermal conductivity of the styrene resin foam molded article. With a styrene resin foam molded article with a lower thermal conductivity, even if the expansion ratio is increased, the same heat insulation as a conventional styrene resin foam molded article with a low expansion ratio can be obtained. The use amount of certain expandable styrene resin particles can be reduced. Therefore, a heat insulating material provided with a styrene resin foam molded article can be manufactured at low cost.

  In addition, a foaming agent such as butane or pentane contained in the styrene resin foam molded article has an effect of reducing the thermal conductivity. However, such a foaming agent is removed from the styrene resin foam molded article over time. It is known that the thermal conductivity of the styrenic resin foam molded article increases with the passage of time because it is scattered and replaced with the atmosphere (air), and therefore the heat insulation properties deteriorate with the passage of time.

  Therefore, after the foaming agent such as butane or pentane contained in the styrene resin foam molded article is replaced with air, it is required to keep the thermal conductivity of the styrene resin foam molded article low.

  From the above circumstances, various studies have been made to lower the thermal conductivity of the styrene resin foam molding, and a method of using a radiation heat transfer inhibitor such as graphite in the styrene resin foam molding is known. Yes. The radiation heat transfer inhibitor is a substance that can suppress radiation heat transfer among the heat transfer mechanism that travels in the foam molded body, and is an additive-free system having the same resin, foaming agent, cell structure, and density. Compared with the foamed molded product, the thermal conductivity can be lowered.

  For example, Patent Document 1 proposes expandable styrenic resin particles that can provide a foam having a density of 35 g / L or less and that contain graphite powder that is uniformly distributed.

Patent Document 2 discloses that the density is 10 to 100 kg / m ³ , the closed cell ratio is 60% or more, the average cell diameter is 20 to 1000 μm, and the graphite powder is 0.05 to 9% by weight. A value obtained by dividing an aspect ratio of 5 or more, a volume average particle diameter (50% particle diameter) of 0.1 to 100 μm, a specific surface area of 0.7 m ² / cm ³ or more, and a 90% particle diameter by a 10% particle diameter. A styrenic resin foam molded body of ~ 20 is described.

  Patent Document 3 discloses a foaming property in which a styrene monomer is seed-polymerized into a styrene resin micropellet containing graphite particles in the presence of an aromatic hydrocarbon having 6 to 10 carbon atoms and a foaming agent is added at the same time. A method for producing styrene resin particles has been proposed.

  In Patent Document 4, a resin composition containing a polystyrene-based resin, a flame retardant, graphite, and a volatile foaming agent is melt-kneaded in an extruder, and the resulting melt-kneaded product is extruded into pressurized water from a die, There has been proposed a method of producing expandable styrene resin particles by cutting an extruded melt-kneaded product.

  Patent Document 5 proposes expandable styrenic resin particles containing 0.1 to 25% by mass of graphite having an average particle size exceeding 50 μm.

  In Patent Document 6, styrene and, if necessary, a monomer compound copolymerizable with styrene are polymerized in a suspension aqueous solution in the presence of graphite particles, and a foaming agent is added before, during or after polymerization. A method for producing expandable styrene resin particles has been proposed.

  Patent Document 7 discloses that the thermal conductivity is less than 32 mW / m · K and the density is 25 g measured at 10 ° C. according to DIN52612, in the presence of graphite and a nonionic surfactant. A method for producing expandable styrene resin particles that is less than / L has been proposed.

Special table 2001-525001 JP 2005-2268 A Special table 2009-553687 JP2013-75941A Special table 2002-530450 Special table 2001-522383 Special table 2008-502750

  As in Patent Documents 1 to 7, it is possible to obtain a styrenic resin foam having low thermal conductivity, that is, high heat insulation performance, by using a radiation heat transfer inhibitor such as graphite in a styrene resin foam molded article. it can.

  As a method of containing a radiant heat transfer inhibitor such as graphite in a styrene resin, it is roughly classified into a method of containing graphite in a polymerization step of a styrene monomer and a prepolymerization using a kneading equipment such as an extruder. There is a method of melt-kneading a styrene resin and graphite. Among these production methods, the melt-kneading method using an extrusion kneading facility is excellent from the viewpoint of the initial investment amount and the simplicity of production, but there is room for further improvement in terms of performance such as foamability and heat insulation. . Further, in order to further increase the competitiveness of the styrene resin foam with respect to other materials, further reduction in manufacturing cost is desired.

  Accordingly, an object of the present invention is to easily provide a styrene resin composition in which carbon is highly dispersed. In addition, the present invention easily provides a styrene resin composition and expandable styrene resin particles that can provide a styrene resin foam molded article having high expansion ratio and low thermal conductivity, that is, high heat insulation performance. For the purpose.

  The inventors of the present application have made extensive studies to solve the above-mentioned problems, and as a result, the dispersion of carbon in the melt-kneaded product obtained by controlling the kneading with carbon and the styrenic resin to specific melt-kneading conditions. It was found that the property can be improved. Above all, when used in a styrene resin foam molded article, it can not only achieve high foaming ratio and high closed cell ratio, but also has low thermal conductivity without impairing surface aesthetics even though it contains carbon. Thus, the present inventors have succeeded in obtaining a styrenic resin foam molded article in which the increase in thermal conductivity over time is remarkably suppressed and the heat insulating property is high in the long term, and the present invention has been completed.

That is, the present invention is a method for producing a styrene resin composition including a step of supplying a styrene resin and carbon to a twin screw extruder and melt-kneading, wherein the Q / N of the twin screw extruder is as follows: Relates to a method for producing a styrene-based resin composition satisfying the formula (hereinafter referred to as “a method for producing a styrene-based resin composition according to the present invention”).
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q represents the extrusion amount of the twin screw extruder (kg / hr), N represents the screw rotation speed (rpm), and D represents the twin screw extruder barrel inner diameter (mm).)
In the method for producing a styrene resin composition according to the present invention, it is preferable that the specific energy of the twin screw extruder is 0.10 kWh / kg or more.

  In the method for producing a styrene resin composition according to the present invention, the carbon content is preferably 2 to 90% by weight with respect to 100% by weight of the styrene resin composition.

  In the method for producing a styrenic resin composition according to the present invention, the carbon is preferably at least one selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, activated carbon, and expanded graphite.

  In the method for producing a styrene resin composition according to the present invention, the carbon preferably has an average particle size of 2.5 to 9.0 μm.

  In the method for producing a styrenic resin composition according to the present invention, the laser scattering intensity per carbon unit solution concentration in the styrenic resin composition is 4.0 {% / (mg / ml)} / wt% or more. Is preferred.

  In the method for producing a styrene resin composition according to the present invention, a foaming styrene resin composition can be produced by further adding a foaming agent to the styrene resin composition.

Further, the present invention circulates through a styrenic resin and a step (A) of supplying and melting and kneading carbon to a twin-screw extruder, and a die having a large number of small holes attached after the twin-screw extruder. A method for producing expandable styrenic resin particles, including a step (B) of extruding a foaming agent-containing melt-kneaded material into a cutter chamber filled with water and cutting with a rotary cutter in contact with a die immediately after extrusion,
The Q / N of the twin screw extruder is in the range of the following formula:
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)
The present invention relates to a method for producing expandable styrene resin particles (hereinafter referred to as “method for producing expandable styrene resin particles according to the first aspect of the present invention”).

  In the method for producing expandable styrene resin particles according to the first aspect of the present invention, the specific energy of the twin screw extruder is preferably in the range of 0.10 to 0.30 kWh / kg.

Furthermore, the present invention provides a styrene resin composition through a styrenic resin, a step (C) of supplying and melting and kneading carbon to a twin screw extruder, and a die having a large number of small holes attached after the twin screw extruder. Foaming, including a step (D) of extruding a melt of the product and cutting with a cutter to obtain styrene resin particles, and a step (E) of suspending the styrene resin particles in water and impregnating a foaming agent In which the Q / N of the twin-screw extruder is in the range of the following formula:
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)
The present invention relates to a method for producing expandable styrene resin particles (hereinafter referred to as “method for producing expandable styrene resin particles according to the second invention”).

  In the first and second methods for producing expandable styrene resin particles according to the present invention (hereinafter simply referred to as “method for producing expandable styrene resin particles according to the present invention”), the carbon is graphite, It is preferably at least one selected from the group consisting of graphene, carbon black, carbon nanotubes, activated carbon, and expanded graphite.

  In the method for producing expandable styrene resin particles according to the present invention, the carbon preferably has an average particle size of 2.5 to 9.0 μm.

  In the method for producing expandable styrene resin particles according to the present invention, the carbon is preferably contained in an amount of 2 to 8% by weight with respect to 100% by weight of the expandable styrene resin particles.

  In the method for producing expandable styrene resin particles according to the present invention, the laser scattering intensity per unit solution concentration of the expandable styrene resin particles is preferably 15.0% / (mg / ml) or more.

  In the method for producing expandable styrene resin particles according to the present invention, the laser scattering intensity per carbon unit solution concentration in the expandable styrene resin particles is 4.0 {% / (mg / ml)} / wt% or more. It is preferable that

  In the method for producing expandable styrene resin particles according to the present invention, the foaming agent is preferably contained in an amount of 2 to 10% by weight based on 100% by weight of the expandable styrene resin particles.

  In the method for producing expandable styrene resin particles according to the present invention, when the expandable styrene resin particles are formed into a foam molded article having an expansion ratio of 80 times, the 80 times foam molded article is allowed to stand at 50 ° C. for 30 days. It is preferable that the thermal conductivity at 23 ° C. measured in accordance with JIS A9511: 2006R is 0.0330 (W / mK) or less after standing for 24 hours at a temperature of 23 ° C.

  According to the present invention, a styrenic resin composition having excellent carbon dispersibility can be produced. By using the styrenic resin composition of the present invention, a styrenic resin foam molded article that achieves both a high expansion ratio and a low thermal conductivity, that is, a high heat insulating property, and a foamable styrenic that provides the foamed molded article Resin particles can be obtained.

  According to the present invention, expandable styrene resin particles capable of providing a styrene resin foam molded article having both high expansion ratio and low thermal conductivity, that is, high heat insulation properties can be produced.

(Styrene resin)
The styrenic resin used in the present invention is not limited to styrene homopolymer (styrene homopolymer), but within a range not impairing the effects of the present invention, styrene, other monomers copolymerizable with styrene, or the like The derivative may be copolymerized. However, the brominated styrene / butadiene copolymer described later is excluded.

  Examples of other monomers copolymerizable with styrene or derivatives thereof (hereinafter sometimes referred to as “other monomers or derivatives thereof”) include, for example, methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene. Styrene derivatives such as isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene; polyfunctional vinyl compounds such as divinylbenzene; methyl acrylate, methyl methacrylate, ethyl acrylate, (Meth) acrylic acid ester compounds such as ethyl methacrylate, butyl acrylate and butyl methacrylate; vinyl cyanide compounds such as (meth) acrylonitrile; diene compounds such as butadiene or derivatives thereof; maleic anhydride and itaconic anhydride acid Unsaturated carboxylic acid anhydrides of: N-methylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (2) -chlorophenylmaleimide, N- (4) -bromophenylmaleimide, and N- (1) N-alkyl substituted maleimide compounds such as -naphthylmaleimide and the like. These may be used alone or in combination of two or more.

  Styrenic resins used in the present invention are not limited to styrene homopolymers and / or copolymers of other monomers or derivatives thereof and styrene, but may be other as long as the effects of the present invention are not impaired. A homopolymer of the above monomer or a derivative thereof, or a blend with the copolymer thereof may be used.

  For example, diene rubber reinforced polystyrene, acrylic rubber reinforced polystyrene, and / or polyphenylene ether resin can be blended with the styrene resin used in the present invention.

  Among the styrenic resins used in the present invention, it is relatively inexpensive and can be foam-molded with low-pressure steam or the like without using a special method, and is excellent in the balance of heat insulation, flame retardancy, and buffering properties. Styrene homopolymers, styrene-acrylonitrile copolymers, or styrene-butyl acrylate copolymers are desirable.

  The melt flow rate (hereinafter referred to as “MFR”) of the styrene resin in the present invention is preferably 1 to 15 g / 10 min. When MFR is within this range, it is easy to obtain expandable styrene resin particles, styrene resin pre-expanded particles, and styrene resin foam-molded articles having excellent foamability (high magnification, high volatility) and surface beauty. It is in. The resulting styrenic resin foam molded article has a balance of mechanical strength such as compressive strength, bending strength or bending deflection, and properties such as toughness. A more preferable range is 2 to 10 g / 10 minutes. The MFR in the present invention is a value measured according to JIS K7210.

(carbon)
In the present invention, a styrene resin foam molded article having high heat insulation can be obtained by adding carbon to the styrene resin as a radiation heat transfer inhibitor. The term “radiation heat transfer inhibitor” as used herein refers to a substance having the property of reflecting, scattering, or absorbing near-infrared or infrared light.

  Examples of carbon used in the present invention include graphite, graphene, carbon black, carbon nanotube, activated carbon, expanded graphite and the like. These carbons can be used alone or in combination of two or more. Among these, graphite is preferable because of its high radiation heat transfer suppressing effect on cost. Examples of graphite include flaky graphite, earthy graphite, spherical graphite, and artificial graphite. Among these, flaky graphite is preferable because it exhibits a high radiation suppressing effect. In the present specification, the term “scale-like” also includes a scale-like, flaky or plate-like one.

  In the present invention, graphite preferably has an average particle size of 0.5 to 9.0 μm, more preferably 2.5 to 9.0 μm, and even more preferably 2.5 to 6.0 μm. In the present specification, the average particle size of graphite is measured and analyzed by a laser diffraction scattering method based on the Mie theory based on ISO 13320: 2009, JIS Z8825-1, and the cumulative volume with respect to the volume of all particles is 50%. The average particle size is defined as the particle size (volume average particle size obtained by laser diffraction scattering method).

  The production cost of graphite decreases as the average particle size increases. In particular, graphite having an average particle size of 2.5 μm or more has a low production cost including a pulverization cost, and thus is very inexpensive and can reduce the cost. When the average particle size is 9.0 μm or less, the cell membrane is not easily broken when the pre-expanded particles and the styrene resin foam molded article are produced from the expandable styrene resin particles. There is a tendency that the molding easiness increases and the compressive strength of the styrene resin foam molded article increases.

  Moreover, if the average particle diameter of graphite is 6.0 μm or less, the surface beauty of the molded body is excellent and lower thermal conductivity, that is, higher heat insulation can be obtained.

  In the present invention, the carbon content is not particularly limited, but is preferably 0.1 to 90% by weight, more preferably 2 to 90% by weight in 100% by weight of the styrenic resin composition.

  When graphite is used as a preferred embodiment of the present invention, the content thereof is 100% by weight of the styrene resin composition from the viewpoint of the balance between the thermal conductivity reducing effect and the dispersibility of the graphite in the styrene resin composition. It is preferable that it is 2 to 90 weight%. If the graphite content is 2% by weight or more, the effect of reducing the thermal conductivity tends to be sufficient, while if it is 90% by weight or less, the dispersibility of carbon in the styrene-based resin composition tends to be excellent. Due to the excellent dispersibility of carbon, the effect of suppressing radiant heat transfer with respect to the carbon content tends to be expanded.

  When graphite is used as a preferred embodiment of the present invention, the styrene resin composition is suitable for expandable styrene resin particles and foam molded articles. In this case, the graphite content is preferably 2% by weight or more and 8% by weight or less at 100% by weight of the styrene resin composition. The styrene resin composition can also be used as a carbon-containing masterbatch. In this case, the styrenic resin composition of the present invention is preferably used so that it becomes 2 wt% or more and 8 wt% or less in the foamable styrene resin particles or 100 wt% of the foamed molded product. When the graphite content is 2% by weight or more, the thermal conductivity reducing effect tends to be sufficient. When the graphite content is 8% by weight or less, pre-expanded particles and a styrene resin foam molded article are produced from graphite and a styrene resin. In addition, since the cell membrane is not easily broken, high foaming is easy and control of the expansion ratio tends to be easy. Further, the graphite content is more preferably 3% by weight or more and 7% by weight or less. When the content of graphite is 3% by weight or more, the thermal conductivity becomes lower, that is, higher heat insulating properties can be obtained. Further, when the graphite content is 7% by weight or less, the foamability and the surface beauty of the molded article are improved. As an embodiment in which the styrene resin composition can also be applied as a carbon-containing master batch, the carbon content is preferably 20 to 90% by weight in 100% by weight of the styrene resin composition.

  About expandable styrene resin particle | grains of this invention, it is preferable that carbon content is 2 to 8 weight% in 100 weight% of expandable styrene resin particles. Even when graphite is contained as one embodiment of the expandable styrene resin particles of the present invention, the graphite content is preferably 2% by weight or more and 8% by weight or less in the resin composition of the expandable styrene resin particles. The more preferred ranges are applicable as well.

(Foaming agent)
In the present invention, a foaming agent may be further added to the styrene resin composition to form a foamable styrene resin composition (“styrene resin composition” is an expandable styrene resin composition as one embodiment). Included). The expandable styrenic resin composition can be formed into an expandable styrene resin particle and an in-mold foam molded body, which will be described later, or formed into an extruded foam. The foaming agent used in the present invention is not particularly limited, but a hydrocarbon having 3 to 6 carbon atoms is desirable and more desirable from the viewpoint of a good balance between foamability and product life, and easy increase in magnification when actually used. Is a hydrocarbon having 4 to 5 carbon atoms. When the foaming agent has 3 or more carbon atoms, the volatility is low, and foaming agent is difficult to dissipate when it is made into expandable styrene resin particles. In addition, it is possible to obtain a sufficient foaming force, and it is preferable because high magnification can be easily achieved. Moreover, since the boiling point of a foaming agent is not too high as carbon number is 6 or less, it becomes easy to obtain sufficient foaming force by the heating at the time of preliminary foaming, and it becomes the tendency for high foaming to be easy. Examples of the hydrocarbon having 3 to 6 carbon atoms include hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, neopentane, cyclopentane, normal hexane, and cyclohexane. These may be used individually by 1 type and may be used in combination of 2 or more type. In addition, it is particularly preferable to contain at least one selected from the group consisting of isobutane, normal butane, isopentane, and normal pentane as a foaming agent from the standpoint of ease of high magnification and product life.

  The amount of the foaming agent added in the present invention is preferably 2 to 10 parts by weight, more preferably 4 to 10 parts by weight, with respect to 100 parts by weight of the styrene resin composition. When the expandable styrenic resin particles are used, the balance between the foaming speed and the foaming force is better, and the effect is that the higher magnification can be achieved more stably. When the addition amount of the foaming agent is 4 parts by weight or more, the foaming force necessary for foaming is sufficient, so that it is easy to achieve high foaming, and it becomes easy to produce a styrene resin foam molded article having a high foaming ratio of 50 times or more. Tend. In addition, when the amount of the foaming agent is 10 parts by weight or less, the flame retardancy is good, and the production time (molding cycle) for producing the styrene resin foam molded article is shortened, so the production cost is low. Tend to be. In addition, it is more preferable that it is 4.5-9 weight part with respect to 100 weight part of styrene-type resin compositions, and, as for the addition amount of a foaming agent, it is still more preferable that it is 5-8.5 weight part.

(Flame retardants)
The styrene resin composition of the present invention may contain a flame retardant. The flame retardant used in the present invention is not particularly limited, and any flame retardant conventionally used in styrene resin foam molded products can be used. Among them, a brominated flame retardant having a high flame retardant imparting effect is used. desirable. Examples of the brominated flame retardant used in the present invention include 2,2-bis [4- (2,3-dibromo-2-methylpropoxy) -3,5-dibromophenyl] propane (also known as tetrabromobisphenol A). -Bis (2,3-dibromo-2-methylpropyl ether)) or 2,2-bis [4- (2,3-dibromopropoxy) -3,5-dibromophenyl] propane (also known as: tetrabromobisphenol A) -Brominated bisphenol compounds such as bis (2,3-dibromopropyl ether)), tetrabromocyclooctane, tris (2,3-dibromopropyl) isocyanurate, brominated styrene / butadiene block copolymer, brominated random Brominated polymers such as styrene / butadiene copolymer or brominated styrene / butadiene graft copolymer Diene-vinyl aromatic hydrocarbon copolymer (e.g., as disclosed in JP-T-2009-516019), and the like. These brominated flame retardants may be used alone or in combination of two or more.

  The brominated flame retardant is easily controlled to the target expansion ratio and has a bromine content of preferably 0.8 wt.% In 100 wt% of the styrene resin composition from the viewpoint of balance such as flame retardancy when carbon is added. % Or more, and more preferably 5.0% by weight or less. If the bromine content is 0.8% by weight or more, the flame retardancy imparting effect tends to increase, and if it is 5.0% by weight or less, the strength of the resulting styrene-based resin foam molding tends to increase. . The styrene resin composition and the expandable styrene resin particles are blended so that the bromine content is more preferably 1.0 to 3.5% by weight.

(Heat stabilizer)
In the present invention, by further using a thermal stabilizer, it is possible to suppress deterioration of flame retardancy and degradation of styrene resin due to decomposition of the brominated flame retardant in the production process. The heat stabilizer in the present invention can be used in appropriate combination depending on the type of styrene resin used, the type and content of foaming agent, the type and content of carbon, the type and content of flame retardant, and the like. .

  As the thermal stabilizer used in the present invention, a hindered amine compound, a phosphorus compound, a phenolic stabilizer, or an epoxy compound is desirable because the weight reduction temperature in the thermogravimetric analysis of the brominated flame retardant-containing mixture can be arbitrarily controlled. . A heat stabilizer can be used individually by 1 type or in combination of 2 or more types. These heat stabilizers can also be used as light-resistant stabilizers as described later.

(Radical generator)
In the present invention, by further containing a radical generator, high flame retardancy can be exhibited by using it together with a brominated flame retardant.

  The radical generator in the present invention is used in appropriate combination according to the type of styrene resin used, the type and content of the foaming agent, the type and content of the radiation heat transfer inhibitor, and the type and content of the brominated flame retardant. be able to.

  Examples of the radical generator used in the present invention include cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, or poly-1,4- Examples include diisopropylbenzene. A radical generator can be used individually by 1 type or in combination of 2 or more types.

(Other additives)
The styrenic resin composition according to the present invention is a processing aid, a light-resistant stabilizer, a nucleating agent, a foaming aid, an antistatic agent, a pigment, etc., as necessary, within a range not impairing the effects of the present invention. One or more other additives selected from the group consisting of the above colorants may be contained.

  Examples of the processing aid include sodium stearate, magnesium stearate, calcium stearate, zinc stearate, barium stearate, or liquid paraffin.

  Examples of the light resistance stabilizer include the hindered amines, phosphorus stabilizers, and epoxy compounds described above, phenol antioxidants, nitrogen stabilizers, sulfur stabilizers, and benzotriazoles.

  Examples of nucleating agents include silica, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, calcium carbonate, sodium bicarbonate, talc and other inorganic compounds, methyl methacrylate copolymers, or ethylene- Polymer compounds such as vinyl acetate copolymer resins, olefinic waxes such as polyethylene wax, or fatty acid bisamides such as methylene bisstearyl amide, ethylene bisstearyl amide, hexamethylene bispalmitic acid amide, ethylene bisoleic acid amide, etc. Can be mentioned.

  As the foaming aid, a solvent having a boiling point of 200 ° C. or lower under atmospheric pressure can be preferably used. For example, an aromatic hydrocarbon such as styrene, toluene, ethylbenzene, or xylene, an alicyclic ring such as cyclohexane, or methylcyclohexane. Formula hydrocarbons, or acetates such as ethyl acetate or butyl acetate.

  In addition, as an antistatic agent and a coloring agent, what is used for various resin compositions can be used without limitation.

  These other additives can be used alone or in combination of two or more.

(Method for producing styrene-based resin composition)
The method for producing a styrenic resin composition and an expandable styrene resin composition of the present invention (hereinafter sometimes simply referred to as “a process for producing a styrenic resin composition of the present invention”) includes a styrenic resin and carbon. In the melt-kneading step of supplying to a twin-screw extruder and melt-kneading, the Q / N in the twin-screw extruder is controlled within a range satisfying the following formula.
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)
The form of supplying the styrene resin and carbon to the twin screw extruder in the present invention is not particularly limited, but powdery carbon is supplied to the styrene resin and the twin screw extruder from the point of high effectiveness of the present invention. It is preferable to melt and knead. That is, the present invention does not require a prior kneading step of carbon and styrene resin, such as using a master batch prepared by kneading carbon and styrene resin in advance. A method for producing a styrene resin composition, which can be directly supplied to a twin-screw extruder and melt-kneaded to obtain a styrene resin composition, thereby providing a styrene resin foam molded article having excellent production cost and excellent heat insulation performance. Can be provided. By securing the Q / N in the above-mentioned specific range in the twin-screw extruder, the dispersion state of carbon in the styrene resin becomes good, and in turn, the styrene resin foam molded article having high heat insulation performance and high foamability. It was found that can be obtained at low cost.

  In addition, this invention does not exclude using the masterbatch produced by kneading | mixing carbon and a styrene resin beforehand.

  As the twin-screw extruder used in the present invention, a known twin-screw extruder can be used, but the same-direction meshing twin-screw extruder is preferable. The single screw extruder of the kneading equipment capable of continuously obtaining the styrene resin composition tends to be inferior in carbon dispersibility as compared with the twin screw extruder. Further, kneaders such as batch mixers and kneaders tend to be less productive than carbon extruders, although they tend to excel in carbon dispersibility. From the above, a continuous twin-screw extruder is excellent as a method for producing a styrene resin composition having both performance and cost.

(Each condition in the melt-kneading process)
Each condition of the melt-kneading process in the twin-screw extruder of polystyrene resin and carbon in the manufacturing process of the styrene resin composition will be described.

(Q / N)
Q / N in a twin screw extruder is 8.0 × 10 ⁻⁶ × D ³ or less regardless of the presence or absence of a foaming agent. The lower the Q / N, the better the carbon dispersion state. As a result, it is possible to obtain a polystyrene resin composition capable of giving a styrene resin foam molded article having high heat insulation performance. If it exceeds 8.0 × 10 ⁻⁶ × D ³ , the dispersion of carbon in the polystyrene resin becomes insufficient, and the heat insulation performance tends to deteriorate. In order to ensure high heat insulation performance, the preferable range is 6.5 × 10 ⁻⁶ × D ³ or less.

  Q / N indicates a value obtained by dividing the amount of extrusion (kg / hr) per unit time of the twin screw extruder by the number of rotations (rpm) of the screw of the twin screw extruder, and D is the value of the twin screw extruder. The barrel inner diameter (mm) is shown. In general, the amount of extrusion is roughly determined by the inner diameter of the barrel of the twin-screw extruder, and the larger the D, the larger the amount of extrusion can be processed. As a result of intensive studies by the present inventors, in the present invention, by controlling the Q / N within a certain range regardless of the value of D, that is, regardless of the size of the extruder and the production scale, It has been found that a polystyrene-based resin composition that can realize a highly dispersed state and, as a result, can provide a styrene-based resin foam having high heat insulation performance can be easily obtained.

(Specific energy)
The specific energy in the twin-screw extruder is preferably 0.10 kWh / kg or more, more preferably 0.13 kWh / kg or more, regardless of the presence or absence of a foaming agent. The higher the specific energy, the better the dispersion state of carbon, and as a result, it becomes easier to obtain a polystyrene resin composition that can give a styrene resin foam molded article having high heat insulation performance. If it is less than 0.10 kWh / kg, the Q / N effect may be reduced. On the other hand, it is preferably 0.30 kWh / kg or less from the viewpoint of preventing decomposition of the styrene resin.

  In addition, the manufacturing method of the 1st expandable styrene resin particle mentioned later, ie, a styrene resin, carbon, and additives, such as a flame retardant, a radical generator, and a stabilizer, are supplied to a twin-screw extruder as needed. Melted and kneaded, and the foaming agent is dissolved and dispersed in the resin by the above-mentioned twin screw extruder or the dispersing equipment after the twin screw extruder, and through a die having many small holes attached after the extruder, with pressurized circulating water. In the method of extruding a foaming agent-containing melt-kneaded material into a filled cutter chamber, cutting the melt-kneaded material with a rotary cutter in contact with a die immediately after extrusion, and cooling and solidifying with pressurized circulating water, a twin-screw extruder The specific energy range is preferably 0.1 to 0.30 kWh / kg. If it exceeds 0.30 kWh / kg, the resin temperature in the twin-screw extruder may increase, and as a result, the shape of the expandable styrene resin particles may be distorted. If the shape of the expandable styrene resin particles is distorted, it may be difficult to increase the magnification, or the appearance of the foamed molded product may be poor.

  Specific energy refers to the value expressed per unit extrusion mass of the work done by the twin-screw extruder for all raw materials supplied to the twin-screw extruder, and the electric power consumption of the twin screw extruder taking into account motor efficiency The amount can be determined by dividing the extrusion mass by the mass of all raw materials extruded per unit time.

<Method for producing expandable styrene resin particles>
Examples of the method for producing the expandable styrene resin particles according to the present invention include the following two methods.

  As a method for producing the first expandable styrene resin particles, a styrene resin, carbon, and additives such as a flame retardant, a radical generator, and a stabilizer are supplied to a twin screw extruder and melt kneaded. A cutter filled with pressurized circulating water through a die having a large number of small holes attached to the extruder after the foaming agent is dissolved and dispersed in the resin by the twin screw extruder or the dispersing equipment after the twin screw extruder. This is a method in which a foaming agent-containing melt-kneaded product is extruded into a chamber, and immediately after the extrusion, the melt-kneaded product is cut with a rotary cutter in contact with a die and cooled and solidified with pressurized circulating water.

  As a method for producing the second expandable styrene resin particles, a styrene resin, carbon, and additives such as a flame retardant, a radical generator and a stabilizer are melt-kneaded with a twin screw extruder, After extruding the melt-kneaded product through a die having a styrene resin particles by cutting with a cutter, the styrene resin particles are suspended in water and a blowing agent is supplied to It is a manufacturing method which obtains an expandable styrene resin particle by making it contain in a styrene resin particle. Granulation by cutting with a cutter may be either a cold cut method or a hot cut method.

  Due to the simplicity of equipment, the blowing agent is injected directly into the twin screw extruder that supplies styrene resin, carbon, and other flame retardants, radical generators, stabilizers, and other additives, melts and kneads the resin. The melt-kneaded product is extruded into a cutter chamber filled with circulating water through a die having a large number of small holes attached after the extruder, and immediately after the extrusion, the melt-kneaded product is removed by a rotary cutter in contact with the die. A method for producing expandable styrene resin particles to be cut is preferred.

  In the method for producing expandable styrene resin particles according to the present invention, as the melt kneading step in the first and second methods for producing expandable styrene resin particles, the melt kneading in the method for producing the above styrene resin composition. Processes can be applied as well. In the first and second methods for producing expandable styrene resin particles, the component of the expandable styrene resin particles (styrene resin composition for expandable particles) is used in the above-described styrene resin composition. Styrenic resins, carbon, other components (foaming agents, additives, etc.) can be used in the same manner unless otherwise specified.

(Resin temperature at the tip of the twin screw extruder)
In the method for producing expandable styrene resin particles according to the present invention, the resin temperature at the tip of the twin screw extruder may affect the decomposition of the flame retardant and the cutting of the melt. It is preferable that it is 160 degreeC or more and less than 210 degreeC in an apparatus front-end | tip, More preferably, it is 160 degreeC or more and less than 190 degreeC. If the resin temperature at the tip of the twin-screw extruder exceeds 210 ° C., the flame retardant may be decomposed. As a result, the styrene resin composition for expandable particles may be deteriorated and the flame retardant performance may be lowered. .

  Furthermore, in the case of the above-described method for producing the first expandable styrenic resin particles, when the resin cooling equipment is not provided between the twin screw extruder and the die, the resin temperature at the tip of the twin screw extruder is set at the time of resin cutting. The temperature of the molten resin can be greatly affected. In this case, if the resin temperature at the tip of the twin-screw extruder is 190 ° C. or higher, the resin temperature at the time of resin cutting with a die may increase, and the shape of the expandable styrene resin particles may be distorted. If the temperature exceeds 210 ° C., the resin tends to be wound around the cutter at the time of cutting with the cutter, so that cutting may be very difficult.

(Each condition of the granulation process)
The conditions of the granulation process of the styrene resin particle in the manufacturing method of the 1st and 2nd expandable styrene resin particle are demonstrated.

  The die is not particularly limited, and examples include a die having a small hole having a diameter of 0.3 mm to 2.0 mm, and preferably 0.4 mm to 1.0 mm.

  In the first method for producing expandable styrene-based resin particles, the temperature of the molten resin immediately before being extruded from the die is Tg + 40 ° C. or higher, where Tg is the glass transition temperature of the resin in a state where no foaming agent is contained. It is preferable that it is Tg + 40 degreeC-Tg + 110 degreeC, and it is further more preferable that it is Tg + 60 degreeC-Tg + 90 degreeC. In the case of a styrene homopolymer, since Tg is about 100 ° C, a preferable temperature range is 140 to 210 ° C, and a more preferable range is 160 ° C to 190 ° C.

  In the first method for producing expandable styrenic resin particles, if the temperature of the molten resin immediately before being extruded from the die is Tg + 40 ° C. or higher, the viscosity of the extruded molten resin is lowered, and small pore clogging occurs. Since it is difficult and the aperture ratio of the small pores does not decrease, it is possible to avoid a situation where the shape of the resulting expandable styrene resin particles is distorted or irregular. On the other hand, when the temperature of the molten resin immediately before being extruded from the die is Tg + 110 ° C. or less, the extruded molten resin is easily solidified, and is difficult to wind around the rotary cutter, and can be stably cut.

  Although it does not specifically limit as a cutting device which cut | disconnects the molten resin extruded to the circulation pressurization cooling water in the manufacturing method of a 1st expandable styrene-type resin particle, For example, it is cut | disconnected with the rotary cutter which contacts dice | dies and is small. Examples thereof include a device that is spheroidized, transferred to a centrifugal dehydrator without defoaming in pressurized circulating cooling water, and dewatered and collected.

The conditions for pressurized circulating cooling water should be adjusted according to the styrenic resin, additives, foaming agent, carbon type, and content used, but the foaming of the molten resin extruded from the die is suppressed and stable. The conditions for cutting with a cutter are preferred. Specifically, in the case of a styrene homopolymer, the temperature condition of the pressurized circulating cooling water is preferably 45 ° C to 75 ° C, more preferably 50 to 65 ° C. The pressure condition, the true density of the resulting expandable styrene resin particles preferably ^{950kg / m 3 ~1050kg / m 3} , more preferably such that the 1000~1050kg / m ^3, to adjust the pressure. Although depending on the type of foaming agent to be used, when butane or pentane is used as the foaming agent, it is preferably 0.6 to 2.0 MPa, more preferably 0.7 to 1.7 MPa, and still more preferably 0.8. ~ 1.5 MPa.

  In the method for producing expandable styrene resin particles of the present invention, the conditions for impregnation with the foaming agent in the method for producing the second expandable styrene resin particles may be the same as those generally performed, and are appropriately set. do it.

<Styrenic resin composition, expandable styrene resin particles>
In the present invention, the dispersion state of carbon in the styrene resin composition and the expandable styrene resin particles can be controlled by Q / N in the twin screw extruder, and by making the dispersion state of carbon good. The present inventors have found that high heat insulation performance can be exhibited when a foamed molded body is used.

(Laser scattering intensity)
In the present invention, the carbon dispersion state can be evaluated by the laser scattering intensity per unit solution concentration measured by a laser diffraction scattering method. The laser scattering intensity of the present invention is determined as follows. First, the intensity Lb of transmitted light when a styrene resin composition or a toluene solution containing no expandable styrene resin particles is irradiated with a He-Ne laser beam having a wavelength of 632.8 nm, and the styrene resin composition or foamability. The laser scattering intensity Ob (%) is obtained from the following equation from the intensity Ls of transmitted light when a He—Ne laser beam having a wavelength of 632.8 nm is irradiated on a toluene solution containing a predetermined weight of styrene resin particles.

Formula Ob = (1-Ls / Lb) × 100
Next, the laser scattering intensity per unit solution concentration of the styrene resin composition or expandable styrene resin particles is determined from the determined laser scattering intensity Ob. The laser scattering intensity calculated by dividing the obtained laser scattering intensity per unit solution concentration by the carbon content (% by weight) of the predetermined weight of the styrene resin composition or expandable styrene resin particles is the carbon unit. The laser scattering intensity per solution concentration.

  The styrene resin composition or expandable styrene resin particle according to the present invention has a laser scattering intensity of 15.0% / (mg / ml) or more per unit solution concentration of the styrene resin composition or expandable styrene resin particle. It is preferable that When the laser scattering intensity is 15.0% / (mg / ml) or more, a high thermal conductivity reduction effect can be achieved when a foamed molded product is used. Especially, in embodiment containing carbon with an average particle diameter of 2.5-9.0 micrometers, the thermal conductivity reduction effect is remarkable. Specifically, when the expandable styrenic resin particles are made into a foam molded article having an expansion ratio of 80 times, the 80 times foam molded article is allowed to stand at a temperature of 50 ° C. for 30 days, and further at a temperature of 23 ° C. After standing for 24 hours, the thermal conductivity at 23 ° C. measured according to JIS A9511: 2006R is preferably 0.0330 (W / mK) or less. Furthermore, when the laser scattering intensity is 17.5% / (mg / ml) or more, it is possible to obtain a higher thermal conductivity reduction effect when the foamed molded body is used. Specifically, when the expandable styrenic resin particles are made into a foam molded article having an expansion ratio of 80 times, the 80 times foam molded article is allowed to stand at a temperature of 50 ° C. for 30 days, and further at a temperature of 23 ° C. It is more preferable that the thermal conductivity at 23 ° C. measured in accordance with JIS A9511: 2006R is 0.0320 (W / mK) or less after standing for 24 hours. That is, it is possible to achieve a high expansion ratio and low thermal conductivity, that is, high heat insulation.

  The styrene resin composition or expandable styrene resin particles according to the present invention preferably have a laser scattering intensity per carbon unit solution concentration of 4.0 {% / (mg / ml)} / wt% or more. When the laser scattering intensity is 4.0% / (mg / ml) / weight% or more, a high thermal conductivity reduction effect can be achieved when a foam molded article is formed. Especially, in embodiment containing carbon with an average particle diameter of 2.5-9.0 micrometers, the thermal conductivity reduction effect is remarkable. Specifically, when the expandable styrenic resin particles are made into a foam molded article having an expansion ratio of 80 times, the 80 times foam molded article is allowed to stand at a temperature of 50 ° C. for 30 days, and further at a temperature of 23 ° C. After standing for 24 hours, the thermal conductivity at 23 ° C. measured according to JIS A9511: 2006R is preferably 0.0330 (W / mK) or less. Furthermore, when the laser scattering intensity is 4.9 {% / (mg / ml)} / weight% or more, it is possible to obtain a higher thermal conductivity reduction effect. It becomes possible to obtain a high thermal conductivity reduction effect with respect to the carbon content. Specifically, when the expandable styrenic resin particles are made into a foam molded article having an expansion ratio of 80 times, the 80 times foam molded article is allowed to stand at a temperature of 50 ° C. for 30 days, and further at a temperature of 23 ° C. It is more preferable that the thermal conductivity at 23 ° C. measured in accordance with JIS A9511: 2006R is 0.0320 (W / mK) or less after standing for 24 hours. That is, it is possible to achieve a high expansion ratio and low thermal conductivity, that is, high heat insulation.

(Pre-expanded resin particles and production method thereof)
The styrene resin composition according to the present invention may be used as a raw material for expandable styrene resin particles as a master batch, or as an expandable styrene resin composition containing a foaming agent, expandable styrene resin particles. Alternatively, it may be molded into a styrene resin foam molded article. The expandable styrene resin particles according to the present invention can be used for an in-mold expanded molded article after being pre-expanded.

  The expandable styrenic resin particles according to the present invention are formed in a conventionally known pre-foaming step, for example, by foaming 10 to 110 times with heated steam to obtain pre-foamed resin particles, and after curing for a certain period of time if necessary. Can be used. The obtained pre-expanded resin particles are molded with water vapor (for example, in-mold molding) using a conventionally known molding machine to produce a styrene resin foam molded article. Depending on the shape of the mold used, it is possible to obtain a molded article having a complicated shape or a block-like molded article.

  The expandable styrene resin particles according to the present invention can be formed into a styrene resin foam molded article having a high expansion ratio. The expansion ratio of the foamed molded article is preferably 40 times or more, more preferably 60 times or more, and particularly preferably 80 times or more. According to the styrenic resin composition and expandable styrene resin particles according to the present invention, a low thermal conductivity can be achieved even when a styrene resin foam molded article having an expansion ratio of 80 times or more, so that the production cost is low, High-performance heat insulation performance can be expressed as a foamed styrenic resin foam molding. In addition, about a heat insulating material, since it is used for a long time, maintenance of the heat insulation performance after progress for a long time is an important subject. For the styrene resin foam molded article molded with the styrene resin composition and the expandable styrene resin particles according to the present invention, a thermal conductivity measurement sample is cut out from the styrene resin foam molded article, and the sample is subjected to 50 ° C. conditions. Even after annealing for 30 days and standing at 23 ° C. for 24 hours, low thermal conductivity can be achieved. By annealing at 50 ° C. for 30 days, the content of hydrocarbon-based foaming agents such as butane and pentane contained in the styrene-based resin foam molded article is 0.5% or less, and the foaming agent is heated. The influence on the conductivity is negligible, and it can be evaluated as the thermal conductivity when the styrene resin foam molded article is used at room temperature for a long time.

  When the expandable styrenic resin particles were made into a foamed molded article having an expansion ratio of 80 times, the 80-fold expanded molded article was allowed to stand at a temperature of 50 ° C. for 30 days, and further allowed to stand at a temperature of 23 ° C. for 24 hours. After that, the thermal conductivity at 23 ° C. measured according to JIS A9511: 2006R is preferably 0.0330 (W / mK) or less. That is, if it is 0.0330 (W / mK) or less, it can be said that a very low thermal conductivity and consequently high heat insulation can be maintained over a long period of time. More preferably, it is 0.0320 (W / mK) or less.

In the present specification, the expansion ratio is expressed in units of “times” or “cm ³ / g”, which have the same meaning.

  The styrene resin pre-expanded particles and the styrene resin foam molded article according to the present invention have an average cell diameter of preferably 70 to 300 μm, more preferably 90 to 250 μm, and still more preferably 100 to 200 μm. When the average cell diameter is in the above-described range, a styrenic resin foam molded article with higher heat insulation is obtained. When the average cell diameter is 70 μm or more, the expansion ratio tends to be easily increased. When the average cell diameter is 300 μm or less, it is possible to avoid an increase in thermal conductivity, that is, deterioration of the heat insulating performance.

(Use of foamed molded products)
The foam molded article molded using the styrene resin composition and expandable styrene resin particles according to the present invention is excellent in surface beauty, has a high expansion ratio and a high closed cell ratio, and has a low thermal conductivity. In addition, the increase in thermal conductivity over time is remarkably suppressed, and the heat insulating property is high in the long term. Therefore, it is suitable for various uses such as, for example, a building heat insulating material, a food container box, a cold box, a buffer material, an agricultural and fishery box, a bathroom heat insulating material, and a hot water storage tank heat insulating material.

  One embodiment of the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims, and technical means disclosed in different embodiments are appropriately combined. The obtained embodiment is also included in the technical scope of the embodiment of the present invention.

  Hereinafter, although one Embodiment of this invention is described concretely based on an Example and a comparative example, this invention is not limited to these.

  In addition, the measuring methods and evaluation methods in the following examples and comparative examples are as follows.

(Measurement of thermal conductivity of styrene resin foam moldings)
In general, it is known that the higher the measurement average temperature of the thermal conductivity, the larger the value of the thermal conductivity. In order to compare the heat insulation, it is necessary to determine the measurement average temperature. In this specification, 23 ° C. defined in JIS A9511: 2006R, which is a standard for foamed plastic heat insulating materials, is adopted as a standard. In addition, in order to evaluate the thermal conductivity when the foaming agent is replaced with air after a long period of time, a thermal conductivity measurement sample is cut out from the styrene resin foam molded article, and the sample is allowed to stand at 50 ° C. for 30 days. And then allowed to stand at a temperature of 23 ° C. for 24 hours, and then the thermal conductivity was measured.

  By annealing at 50 ° C. for 30 days, the content of hydrocarbon-based foaming agents such as butane and pentane contained in the styrene-based resin foamed molded article is 0.5% or less, which is given to the thermal conductivity. The influence becomes minor, and the thermal conductivity when the styrene resin foam molded article is used at room temperature for a long time can be evaluated almost accurately.

  More specifically, a sample having a length of 300 mm, a width of 300 mm, and a thickness of 25 mm was cut out from the styrene-based resin foam molding. The sample was allowed to stand at a temperature of 50 ° C. for 30 days, and further allowed to stand at a temperature of 23 ° C. for 24 hours. Then, a thermal conductivity measuring device (HC-074 manufactured by Eihiro Seiki Co., Ltd.) was used. In accordance with JIS A1412-2: 1999, the thermal conductivity was measured at an average temperature of 23 ° C. and a temperature difference of 20 ° C. by a heat flow meter method.

(Measurement of carbon content)
About 10 mg each of the expandable styrene resin particles or the styrene resin foam molded article was used as a sample. This sample was continuously subjected to the following I to III using a thermogravimetric apparatus (TG / DTA 220U, manufactured by SII NanoTechnology Co., Ltd.) equipped with a thermal analysis system: EXSTAR6000. The amount was expressed as carbon weight and expressed as a percentage of the specimen weight.
I. The temperature was raised from 40 ° C. to 600 ° C. at 20 ° C./min under a nitrogen stream of 200 mL / min, and then kept at 600 ° C. for 10 minutes.
II. The temperature was lowered from 600 ° C. to 400 ° C. at 10 ° C./min under a nitrogen stream of 200 mL / min, and held at 400 ° C. for 5 minutes.
III. The temperature was raised from 400 ° C. to 800 ° C. at 20 ° C./min under an air stream of 200 mL / min, and then kept at 800 ° C. for 15 minutes.

(Measurement of average particle diameter D50 (μm) of carbon and laser scattering intensity (%))
(1) Sample solution adjustment conditions (a) In the case where the measurement object is expandable styrene resin particles and styrene resin foam molded article 500 mg each of expandable styrene resin particles and styrene resin foam molded article (sample), 0 A sample solution was prepared by dissolving and dispersing in 20 mL of a 1% (w / w) span 80 toluene solution.

(B) When the measurement object is carbon before kneading, that is, the raw material carbon itself 20% carbon and 480 mg of styrene resin (680 Japan, 680) are 0.1% (w / w) span 80 toluene solution A sample solution was prepared by dissolving and dispersing in 20 mL.

  In addition, said melt | dissolution / dispersion | distribution means the state which resin melt | dissolved and carbon is disperse | distributing.

(2) Ultrasonic irradiation Next, the sample solution was irradiated with ultrasonic waves under the following conditions with an ultrasonic cleaner to reduce carbon aggregation.
Equipment used: Ultrasonic cleaner manufactured by AS ONE Corporation Model No. USM
Oscillation frequency: 42 kHz
Irradiation time: 10 minutes Temperature: room temperature.

(3) Particle size measurement condition measurement device: Laser diffraction particle size distribution measurement device Mastersizer 3000 manufactured by Malvern
Light source: 632.8 nm red He—Ne laser and 470 nm blue LED
Dispersion unit: Wet dispersion unit Hydro MV
Analysis is performed with the following settings, volume distribution is obtained by measurement / analysis by laser diffraction / scattering method based on Mie theory based on ISO13320: 2009, JIS Z8825-1, and D50 particle size of carbon in the sample is calculated. did.
Particle type: Non-spherical carbon refractive index: 2.42
Carbon absorption rate: 1.0
Dispersion medium: 0.1% (w / w) span 80 Toluene solution Dispersion medium refractive index: 1.49
Number of stirring in the dispersion unit: 2500 rpm
Analysis model: General purpose, single mode maintained Measurement temperature: Room temperature.

(4) Measurement procedure 120 mL of 0.1% (w / w) span 80 toluene solution was injected into the dispersion unit and stirred at 2500 rpm for stabilization. The intensity of the light measured by the central detector when the sample solution sample was not present in the measurement cell and only the dispersion medium was irradiated with the 632.8 nm red He—Ne laser light was defined as the transmitted light intensity Lb. Next, 2 mL of the sonicated sample solution was collected and added to the dispersion unit. The intensity of light measured by the central detector when the sample solution was added and irradiated with 632.8 nm red He—Ne laser light one minute later was defined as the transmitted light intensity Ls. At the same time, the particle size (D50) was measured. From the obtained Ls and Lb, the laser scattering intensity Ob of the sample solution was calculated by the following formula.

    Ob = (1-Ls / Lb) × 100 (%)

  The central detector is a detection unit located in front of the laser beam output and is a measure of transmitted light that was not used for scattering. The laser scattering intensity is a measure of the amount of laser light lost when the laser of the analyzer is scattered on a sample.

(5) Calculation of laser scattering intensity per unit solution concentration of expandable styrene-based resin particles and styrene-based resin foam molded product In the following formula, unit solution concentration of expandable styrene-based resin particles and styrene-based resin foamed molded product The laser scattering intensity per unit was calculated.

Laser scattering intensity (% / (mg / ml)) per unit solution concentration of expandable styrenic resin particles or styrene resin foam molding (sample) = laser scattering intensity (Ob) / {sample weight (500 mg) / toluene Amount (20 mL) × Sample injection amount (2 mL) / Total amount of toluene in dispersion unit (120 mL + 2 mL)}
The laser scattering intensity per unit solution concentration is a value obtained by dividing the measured laser scattering intensity by the sample concentration in toluene. Since this measuring device is a device that needs to measure with a solution, the sample concentration in the toluene solution is kept constant, and a measured value at a constant sample amount is obtained.

(6) Calculation of Laser Scattering Strength per Carbon Unit Solution Concentration in Expandable Styrenic Resin Particles and Styrenic Resin Foam Molded Products In the following formula, expandable styrene resin particles and styrene resin foamed molded products (hereinafter referred to as , Abbreviated as “measuring object.”) The laser scattering intensity per concentration of the carbon unit solution contained therein was calculated.

    Laser scattering intensity per carbon unit solution concentration in measurement object {% / (mg / ml)} / wt% = laser scattering intensity per unit solution concentration of measurement object (% / (mg / ml)) / measurement object Carbon content (wt%)

  It is the essence of one embodiment of the present invention that even if the carbon has the same weight, the heat insulation can be improved by the dispersion state of the contained carbon. The dispersion state of carbon can be evaluated by using the laser scattering intensity per carbon unit solution concentration.

  Since the graphite dispersion state in the expandable styrene resin particles is determined by the graphite dispersion state in the styrene resin composition, the laser scattering intensity per carbon unit solution concentration of the expandable styrene resin particles and the styrene resin composition The laser scattering intensity per carbon unit solution concentration of (expandable styrenic resin composition) is substantially the same.

(7) Calculation of laser scattering intensity per unit solution concentration of mixture of carbon and styrene resin before kneading Laser scattering per unit solution concentration of mixture of carbon and styrene resin before kneading by the following formula Intensity was calculated.

  Laser scattering intensity per unit solution concentration of mixture of carbon and styrene resin before kneading {% / (mg / ml)} = laser scattering intensity (Ob) / [{carbon weight (20 mg) + styrene resin (480 mg) )} / Toluene amount (20 mL) × Sample injection amount (2 mL) / Total toluene amount in dispersion unit (120 mL + 2 mL)].

(8) Laser scattering intensity per carbon unit solution concentration before kneading The laser scattering intensity per carbon before kneading, that is, the raw material carbon unit solution concentration, was calculated by the following equation.

  Laser scattering intensity per carbon unit solution concentration before kneading {% / (mg / ml)} / wt% = laser scattering intensity per unit solution concentration of the mixture of carbon and styrene resin before kneading (% / (mg / Ml)) / carbon content in the mixture of carbon and styrene resin before kneading (20/500 × 100 = 4 wt%).

(Measurement of foaming ratio and evaluation of foaming performance and molding performance)
A sample having a length of 300 mm, a width of 300 mm, and a thickness of 25 mm was cut out from the styrene-based resin foam-molded product, as in the case of measurement of thermal conductivity. While measuring the weight (g) of the sample, the vertical dimension, the horizontal dimension, and the thickness dimension were measured using a caliper. The volume (cm ³ ) of the sample was calculated from each measured dimension, and the expansion ratio was calculated according to the following formula.

Foaming ratio (cm ³ / g) = sample volume (cm ³ ) / sample weight (g)
In addition, as described above, the expansion ratio “times” of the styrene-based resin foam molding is conventionally expressed as “cm ³ / g”.

  Further, the surface of the styrene resin foam molded article having an expansion ratio of 80 times was observed, and it was determined that the surface having good voids between the particles with small voids and the ones with conspicuous voids being poor in surface beauty.

Based on the measured expansion ratio and the beautiful surface of the molded body, the foaming / molding performance of the styrene resin foam was evaluated.
The evaluation of foaming / molding performance was based on the following criteria.
A: A beautiful molded body capable of foaming 80 times is obtained.
◯: Although 80 times foaming is possible, it is difficult to obtain a beautiful molded body.

(Evaluation of flame retardancy)
The produced foamed molded product was allowed to stand at a temperature of 60 ° C. for 48 hours, and further allowed to stand at a temperature of 23 ° C. for 24 hours, and then an oxygen index was measured according to JIS K7201.

(Measurement method of average cell diameter of styrenic resin foam molding)
A styrene resin foam molded article with an expansion ratio of 80 times was cut with a razor, and the cross section was observed with an optical microscope. The number of cells present in the range of 1000 μm × 1000 μm square of the cross section was measured, and the value measured by the following formula (area average diameter) was taken as the average cell diameter. The average cell diameter of five samples was measured, and the average was taken as the average cell diameter.

Average cell diameter (μm) = 2 × [1000 μm × 1000 μm / (number of cells × π)] ^1/2

(Evaluation of foaming agent content in expandable styrene resin particles)
The weight W1 (g) of the expandable styrene resin particles was measured, heated in an oven at 150 ° C. for 30 minutes, then cooled in a desiccator for 30 minutes, and the weight W2 (g) was measured again. The weight difference (W1-W2) before and after heating was taken as the foaming agent content in the expandable styrene resin particles.

Foaming agent content (% by weight) = (W1-W2) / W1 × 100
The raw materials used in the examples and comparative examples are shown below.

(Styrene resin)
(A) Styrene homopolymer [PS Japan Co., Ltd., 680]
(carbon)
(B) Graphite [manufactured by Maruho Castings Co., Ltd., scaly graphite SGP-40B]
Average particle diameter D50 = 5.8 μm
Laser scattering intensity per unit concentration of carbon (graphite) = 3.7%.

(Brominated flame retardant)
(C1) 2,2-bis [4- (2,3-dibromo-2-methylpropoxy) -3,5-dibromophenyl] propane [Daiichi Kogyo Seiyaku Co., Ltd., SR-130, bromine content = 66% by weight]
(C2) Bromination (styrene-butadiene copolymer) [available from Chemtura, EMERALD INNOVATION 3000, bromine content = 65% by weight]

(Heat stabilizer)
(D1) Tetrakis (2,2,6,6-tetramethylpiperidyloxycarbonyl) butane [LA-57 manufactured by ADEKA Corporation]
(D2) Bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite [manufactured by ADEKA PEP-36]
(D3) 3,9-bis (2,4-di-tert-butylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane [Ultranox 626 manufactured by ADDIVANT Corporation]
(D4) Pentaerythritol tetrakis [3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] [ANOX20 manufactured by ADDIVANT]
(D5) Cresol novolac type epoxy resin [manufactured by Huntsman Japan K.K., ECN-1280, epoxy equivalent of 212 to 233 g / eq. ].

(Brominated flame retardant and stabilizer mixture)
(E1) Brominated flame retardant (C1), stabilizers (D1) and (D2) were mixed with a mixer to obtain a mixture (E1) of brominated flame retardant and stabilizer. However, the weight ratio (% by weight) of each material was (C1) :( D1) :( D2) = 95: 2: 3 ((C1) + (D1) + (D2) = 100% by weight).

  (E2) Brominated flame retardant (C2), stabilizers (D3), (D4) and (D5) were mixed with a mixer to obtain a mixture (E2) of brominated flame retardant and stabilizer. However, the weight ratio (% by weight) of each material is (C2) :( D3) :( D4) :( D5) = 86.6: 0.4: 8.7: 4.3 ((C2) + ( D3) + (D4) + (D5) = 100% by weight).

(Radical generator)
(F) Poly-1,4-diisopropylbenzene [manufactured by UNITED INITIATORS, CCPIB]

(Foaming agent)
(G1) Normal pentane [manufactured by SK Sangyo Co., Ltd.]
(G2) Isopentane [manufactured by SK Sangyo Co., Ltd.]
(G3) Isobutane [Mitsui Chemicals, Inc.]
The twin screw extruder, screw design, pre-foaming machine and molding machine used in the comparative examples are shown below.

  (H1) twin screw extruder (1): meshing twin screw extruder (manufactured by Technobel, cylinder inner diameter D = 40 mm, L / D = 32)

  Screw design: At least one forward kneading element and one reverse kneading element were set at least before pressing the foaming agent. In addition, screw design # 3, screw design # 1, and screw design # 2 were designed in ascending order of the number of kneading disk elements before press-fitting the foaming agent, and a total of three screw designs were evaluated.

  (H2) twin screw extruder (2): same direction meshing twin screw extruder (manufactured by Plastic Giken Co., Ltd., cylinder inner diameter D = 26 mm, L / D = 39)

  Screw design: The screw design corresponding to L / D = 32 from the tip of the extruder toward the root of the extruder was the same as the screw design # 1 of the twin screw extruder (1). The remaining portion corresponding to L / D = 7 was a flight, a design that only transports the raw material, and a screw design # 4.

(3) Pre-foaming machine; manufactured by Daikai Kogyo Co., Ltd., BHP-300
(4) Molding machine; manufactured by Daisen Industry Co., Ltd., KR-57
(5) Mold: Mold for molding in mold (length 450 mm × width 310 mm × thickness 25 mm).

Example 1
[Production of expandable styrene resin particles]
Styrenic resin (A), carbon (B), brominated flame retardant and stabilizer mixture (E1) were each fed to the screw design # 1 twin screw extruder (1) using a feeder. The cylinder set temperature after the raw material feed section was 160 ° C., and melt kneading was performed at a screw rotation speed of 129 rpm. Each component of the resin composition was supplied at a weight ratio (parts by weight) of (A) :( B) :( E1) = 93.5: 4.0: 2.5, and the total supply amount was 50 kg / hr. It was.

From the middle of the twin-screw extruder, 4.3 parts by weight of mixed pentane [a mixture of 80% by weight of normal pentane (G1) and 20% by weight of isopentane (G2)] and isobutane (100% by weight of the resin composition) G3) was press-fitted at a rate of 2.2 parts by weight. After that, through a gear pump set at 170 ° C connected to the tip of the twin-screw extruder and a diverter valve, set to 250 ° C with 36 small holes with a diameter of 0.65mm and land length of 3.0mm attached downstream of the diverter valve. The extruded dies were extruded into pressurized circulating water at a temperature of 65 ° C. and 1.3 MPa at an extrusion rate of 53.25 kg / hr. The extruded melt-kneaded product is cut and granulated under a condition of 1800 rpm using a rotary cutter having 10 blades in contact with a die, and is transferred to a centrifugal dehydrator to obtain expandable styrene resin particles. Obtained. The Q / N / D ³ × 10 ⁶ of the twin screw extruder was 6.4, the resin temperature at the tip of the extruder was 176 ° C., and the specific energy was 0.140 kWh / kg.

  After dry blending 0.08 part by weight of zinc stearate with respect to 100 parts by weight of the obtained expandable styrenic resin particles, it was stored at 15 ° C.

[Preparation of pre-expanded particles]
The expandable styrenic resin particles were charged into a pre-foaming machine, and 0.1 MPa of water vapor was introduced into the pre-foaming machine to cause foaming to obtain pre-foamed particles with an expansion ratio of 80 times. The amount of the foaming agent contained in the expandable styrene resin particles at the time of preliminary foaming was 5.7% by weight.

[Production of Styrenic Resin Foamed Molding]
The obtained pre-expanded particles with an expansion ratio of 80 times are filled in an in-mold molding die attached to a polystyrene foam molding machine, and 0.06 MPa of water vapor is introduced to cause in-mold foaming. Water was sprayed for 3 seconds to cool. After holding the styrene resin foam molded body in the mold until the pressure at which the styrene resin foam molded body presses the mold is 0.015 MPa (gauge pressure), the styrene resin foam molded body is taken out, A styrene resin foam molded article was obtained. The expansion ratio was 80 times.

  The expandable styrene resin particles and the styrene resin foam molded article obtained in Example 1 were measured and evaluated according to the various measurement methods described above. The measurement results and evaluation results are shown in Table 1.

(Example 2)
In [Production of expandable styrene resin particles] in Example 1, a styrene resin foam molded article was produced by the same treatment as in Example 1 except that the screw rotation speed was changed to 162 rpm. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 3)
In [Production of expandable styrene resin particles] in Example 1, a styrene resin foam molded article was produced by the same treatment as in Example 1, except that the screw rotation speed was changed to 195 rpm. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 4)
In [Production of expandable styrene resin particles] in Example 1, a styrene resin foam molded article was produced by the same treatment as in Example 1 except that the screw rotation speed was changed to 229 rpm. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 5)
In [Production of expandable styrene resin particles] in Example 1, a styrene resin foam molded article was produced by the same treatment as in Example 1, except that the screw rotation speed was changed to 292 rpm. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 6)
[Production of styrene resin particles]
In [Preparation of Expandable Styrenic Resin Particles] in Example 1, a styrene resin (A), carbon (B), a mixture of a brominated flame retardant and a stabilizer (E2), and a radical generator (F) are fed to each feeder. To the twin screw extruder (1), the cylinder set temperature after the raw material feed section of the twin screw extruder was set to 160 ° C., and melt kneading was performed at a screw rotation speed of 129 rpm. The total supply rate was 50 kg / hr at a weight ratio of (A) :( B) :( E2): radical generator (F) = 93.05: 4.0: 2.75: 0.2. Subsequent operations produced a styrene resin foam molded article by the same treatment as in Example 1. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 7)
In [Preparation of Expandable Styrenic Resin Particles] in Example 1, the styrenic resin foam molded article was treated by the same treatment as in Example 1 except that the screw design was changed to # 2 and the screw rotation speed was changed to 292 rpm. Produced. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 8)
In [Preparation of Expandable Styrenic Resin Particles] in Example 1, the styrenic resin foam molded article was treated by the same treatment as in Example 1 except that the screw design was changed to # 3 and the screw rotation speed was changed to 195 rpm. Produced. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

Example 9
In [Preparation of Expandable Styrenic Resin Particles] in Example 1, the styrenic resin foam molded article was treated by the same treatment as in Example 1 except that the screw design was changed to # 3 and the screw rotation speed was changed to 292 rpm. Produced. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

(Example 10)
[Production of expandable styrene resin particles]
Styrenic resin (A), carbon (B), brominated flame retardant and stabilizer mixture (E1) are each fed to the screw design # 3 twin screw extruder (1) using a feeder. The cylinder set temperature after the raw material feed part was 170 ° C., and melt kneading was performed at a screw rotation speed of 230 rpm. Each component of the resin composition is supplied at a weight ratio (parts by weight) of (A) :( B) :( E1) = 93.5: 4.0: 2.5, and the total supply amount is 70 kg / hr. It was.

From the middle of the twin-screw extruder, 5.0 parts by weight of mixed pentane [a mixture of 80% by weight of normal pentane (G1) and 20% by weight of isopentane (G2)] and isobutane (100% by weight of the resin composition) G3) was press-fitted at a rate of 2.5 parts by weight. After that, through a gear pump set at 170 ° C connected to the tip of the twin screw extruder and a diverter valve, it was set at 250 ° C with 78 small holes of diameter 0.65mm and land length 5.0mm attached downstream of the diverter valve. The extruded dies were extruded into pressurized circulating water at a temperature of 65 ° C. and 1.3 MPa at an extrusion rate of 75.25 kg / hr. The extruded molten resin is cut and granulated under the condition of 2100 rpm using a rotary cutter having 6 blades in contact with the die, and transferred to a centrifugal dehydrator to obtain expandable styrene resin particles. It was. Q / N / D ³ × 10 ⁶ of the twin screw extruder was 5.1, the resin temperature at the tip of the extruder was 185 ° C., and the specific energy was 0.109 kWh / kg.

  After dry blending 0.08 part by weight of zinc stearate with respect to 100 parts by weight of the obtained expandable styrenic resin particles, it was stored at 15 ° C.

  The preparation of the pre-expanded particles and the preparation of the styrene resin foamed molded article were performed in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The measurement results and evaluation results are shown in Table 1.

(Example 11)
Styrenic resin (A), carbon (B), brominated flame retardant and stabilizer mixture (E1) were each fed to the screw design # 1 twin screw extruder (1) using a feeder. The cylinder set temperature after the raw material feed section was 200 ° C., and melt kneading was performed at a screw rotation speed of 125 rpm. The total supply rate was 50 kg / hr at a weight ratio of (A) :( B) :( E1) = 93.5: 4.0: 2.5. The styrenic resin composition melt-kneaded by the extruder is formed into a strand shape through a die provided with 20 small holes with a diameter of 1.4 mm attached to the tip of the extruder, and cooled and solidified in a water bath at 20 ° C. Styrenic resin particles were obtained with a cutter.

[Production of expandable styrene resin particles]
In an autoclave with a stirrer of 6 L in volume, with respect to 100 parts by weight of the obtained styrene resin particles, 200 parts by weight of deionized water, 1 part by weight of tricalcium phosphate, 0.03 part by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of sodium chloride was added, and the autoclave was sealed. Then, after heating to 105 ° C. over 1 hour, 7 parts by weight of mixed pentane [a mixture of 80% normal pentane (B1) and 20% isopentane (B2)] and 1.5 parts by weight of isobutane as a blowing agent were applied over 25 minutes. Then, the mixture was added to the autoclave, heated to 115 ° C. over 10 minutes, and maintained as it was for 4 hours.

  Next, it is cooled to room temperature, the resin particles impregnated with the foaming agent are taken out from the autoclave, pickled with hydrochloric acid, washed with water, dehydrated with a centrifugal separator, and the water adhering to the surface of the resin particles with an air dryer. Drying was performed to obtain expandable styrene resin particles.

  After dry blending 0.08 part by weight of zinc stearate with respect to 100 parts by weight of the obtained expandable styrenic resin particles, it was stored at 15 ° C.

[Preparation of pre-expanded particles]
Two weeks after producing expandable styrene resin particles and storing at 15 ° C., the expandable styrene resin particles were put into a pre-foaming machine [manufactured by Daikai Kogyo Co., Ltd., BHP-300], and 0.1 MPa water vapor Was introduced into a pre-foaming machine and foamed to obtain pre-foamed particles having a bulk magnification of 80 times.

[Production of Styrenic Resin Foamed Molding]
The same operation as in Example 1 was performed to prepare an 80-fold styrene resin foam molded article, and evaluation was performed in the same manner as in Example 1. The measurement results and evaluation results are shown in Table 1.

Example 12
In [Production of expandable styrenic resin particles] in Example 11, a screw design # 4 twin-screw extruder (2) was used and melt-kneaded in the same manner except that the total supply amount was 14 kg / hr. The styrenic resin composition melt-kneaded by the extruder is formed into a strand shape through a die provided with eight small holes with a diameter of 1.4 mm attached to the tip of the extruder, and cooled and solidified in a water bath at 20 ° C. Styrenic resin particles were obtained with a cutter. [Production of expandable styrene-based resin particles], [Preparation of pre-expanded particles], and [Production of styrene-based resin foam molded article] were evaluated by performing the same operations as in Example 11. The measurement results and evaluation results are shown in Table 1.

(Comparative Example 1)
In [Production of expandable styrene resin particles] in Example 1, a styrene resin foam molded article was produced by the same treatment as in Example 1 except that the screw rotation speed was changed to 97 rpm. Evaluation was performed in the same manner as in Example 1, and the measurement results and evaluation results are shown in Table 1.

  From the results of the examples shown in Table 1, by controlling the Q / N so as to satisfy the requirements of the present invention, it is possible to improve the dispersibility of carbon, high foaming ratio, low thermal conductivity, That is, it can be seen that a styrene resin composition capable of providing a styrene resin foam molded article having both high heat insulation performance and a method for producing expandable styrene resin particles can be provided.

Claims (17)

A method for producing a styrene-based resin composition, comprising a step of supplying a styrene-based resin and carbon to a twin-screw extruder and melt-kneading, wherein the Q / N of the twin-screw extruder is in the range of the following formula: A method for producing a styrene-based resin composition.
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)   The method for producing a styrenic resin composition according to claim 1, wherein the specific energy of the twin-screw extruder is 0.10 kWh / kg or more.   The manufacturing method of the styrene resin composition of Claim 1 or 2 whose content of the said carbon is 2-90 weight% with respect to 100 weight% of styrene resin compositions.   The styrene resin composition according to any one of claims 1 to 3, wherein the carbon is at least one selected from the group consisting of graphite, graphene, carbon black, carbon nanotube, activated carbon, and expanded graphite. Manufacturing method.   The manufacturing method of the styrene resin composition as described in any one of Claims 1-4 whose said carbon is an average particle diameter of 2.5-9.0 micrometers.   The styrene resin composition according to claim 5, wherein the laser scattering intensity per carbon unit solution concentration in the styrene resin composition is 4.0 {% / (mg / ml)} / wt% or more. Method.   A foamable styrene resin composition comprising a step of further adding a foaming agent to the styrene resin composition obtained by the method for producing a styrene resin composition according to any one of claims 1 to 6. Production method. Supplying a styrene-based resin and carbon to a twin-screw extruder, melt-kneading step (A), and
A step of extruding a foam-containing melt-kneaded product into a cutter chamber filled with circulating water through a die having a large number of small holes attached after the twin-screw extruder, and cutting with a rotary cutter in contact with the die immediately after extrusion. (B) containing foamable styrene resin particles,
The Q / N of the twin screw extruder is in the range of the following formula:
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)
A method for producing expandable styrene resin particles.   The method for producing expandable styrene resin particles according to claim 8, wherein the specific energy of the twin-screw extruder is in the range of 0.10 to 0.30 kWh / kg. Supplying a styrenic resin and carbon to a twin-screw extruder, melt-kneading step (C),
A step (D) of extruding a melt of the styrenic resin composition through a die having a large number of small holes attached after the twin-screw extruder, and cutting with a cutter to obtain styrenic resin particles; and
A method for producing expandable styrene resin particles, comprising a step (E) of suspending the styrene resin particles in water and impregnating with a foaming agent,
The Q / N of the twin screw extruder is in the range of the following formula:
Q / N ≦ 8.0 × 10 ⁻⁶ × D ³
(In the above formula, Q is the twin-screw extruder extrusion rate (kg / hr), N is the screw rotation speed (rpm), and D is the twin-screw extruder barrel inner diameter (mm).)
A method for producing expandable styrene resin particles.   The expandable styrene resin according to any one of claims 8 to 10, wherein the carbon is at least one selected from the group consisting of graphite, graphene, carbon black, carbon nanotubes, activated carbon, and expanded graphite. Particle production method.   The method for producing expandable styrene resin particles according to any one of claims 8 to 11, wherein the carbon has an average particle size of 2.5 to 9.0 µm.   The method for producing expandable styrene resin particles according to any one of claims 8 to 12, wherein the carbon is contained in an amount of 2 to 8 wt% with respect to 100 wt% of the expandable styrene resin particles.   The expandable styrene resin particles according to any one of claims 12 to 13, wherein the laser scattering intensity per unit solution concentration of the expandable styrene resin particles is 15.0% / (mg / ml) or more. Manufacturing method.   The laser scattering intensity per carbon unit solution concentration in the expandable styrenic resin particles is 4.0 {% / (mg / ml)} / wt% or more, according to any one of claims 12 to 14. Of producing expandable styrene resin particles.   The method for producing expandable styrene resin particles according to any one of claims 8 to 15, wherein the foaming agent is contained in an amount of 2 to 10 wt% with respect to 100 wt% of the expandable styrene resin particles. When the expandable styrenic resin particles were made into a foamed molded article having an expansion ratio of 80 times, the 80-fold expanded molded article was allowed to stand at a temperature of 50 ° C. for 30 days, and further allowed to stand at a temperature of 23 ° C. for 24 hours. After that, the thermal conductivity at 23 ° C. measured in accordance with JIS A9511: 2006R is 0.0330 (W / mK) or less.
The manufacturing method of the expandable styrene-type resin particle as described in any one of Claims 8-16.