JP2019049011A - Foamable particle of styrenic resin, manufacturing method thereof, forming particle, foam product and use thereof - Google Patents

Abstract

To provide a foamable particles of styrenic resin, from which a foam product excellent in thermal insulation properties can be obtained.SOLUTION: A foamable particles of styrenic resin comprises a conductive carbon black having a volume resistivity of 1.0×10Ω cm or less, a styrenic resin, and a foaming agent.SELECTED DRAWING: Figure 2

Description

  The present invention relates to styrenic resin foamable particles and a method for producing the same, foam particles, foam molded articles and uses thereof. More specifically, the present invention relates to a styrenic resin foam molded article excellent in heat insulation and use thereof, styrenic resin foamable particles and foam particles for producing the above-mentioned molded body, and styrenic resin foamable particles On the way.

  In the past, foam molded products are lightweight, and excellent in heat insulation and mechanical strength. Heat insulation materials used in houses and automobiles, heat insulation materials used in construction materials, etc., transportation packing materials such as fish boxes and food containers, cushioning materials It is used for etc. Among them, in-mold foam molded products produced using foamable particles as a raw material are widely used because of their advantages such as easy to obtain a desired shape.

As a foam molded article, a styrene resin foam molded article derived from styrene resin foamable particles is widely used. The styrenic resin foam molded article is prepared by heating the styrenic resin foamable particles and prefoaming them to obtain prefoamed particles, and subsequently heating the obtained prefoamed particles while secondary foaming them in the mold cavity. It is obtained by integrating by fusing.
The styrenic resin foam-molded body has various properties, and for example, it has excellent thermal insulation as its property. Excellent thermal insulation is required for various applications from the viewpoint of energy saving. Specific applications are: thermal insulation for walls, thermal insulation for floors, thermal insulation for roofs, thermal insulation for automobiles, thermal insulation for hot water tanks, thermal insulation for piping, thermal insulation for solar systems, thermal insulation for water heaters, food And containers for industrial products, packaging materials for fish and agricultural products, filling materials, core materials for tatami mats, and the like.

  It is desirable that the heat insulation required of the foam molded body be further improved from the viewpoint of energy saving. As methods of improving heat insulation, various methods such as multiplication, change of resin composition, use of additives and the like are known. For example, in Japanese Patent Application Laid-Open No. 63-183941 (Patent Document 1), a foam-molded article is proposed which contains, as an additive, a fine powder having an infrared reflectance of 40% or more. In the example of Patent Document 1, a foam molded product using aluminum powder, silver powder and graphite powder having a reflectance of 40% or more is a carbon black generally used as a blackening agent in a foam molded product (for example, It is described that heat insulation is superior to a foam molded article containing an additive having a reflectance of less than 40%, such as JP-A 2013-6966: Patent Document 2).

Japanese Patent Application Laid-Open No. 63-183941 JP, 2013-6966, A

  The technique described in the above-mentioned publication makes it difficult to obtain a foam molded article having sufficient thermal insulation required in recent years, and provision of a foam molded article having higher thermal insulation is desired.

The inventors of the present invention examined additives to be added to the foam for improving the heat insulation of the foam. As a result, it has been found that a specific type of carbon black contributes to the improvement of heat insulation. This specific type of carbon black is an additive that can be included in the concept of conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less. Here, considering that carbon black is inferior to the heat insulation improving effect in Patent Document 1, it is unexpectedly found by the inventor that the conductivity of carbon black is related to the heat insulation. Point of view.

Thus, according to the present invention, the conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less, a styrenic resin, and a foaming agent, wherein the primary particles of the conductive carbon black are the styrene The primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregate has an average value of the longest diameter of (i) 180 to 500 nm (where ii) A styrenic resin foamable particle having a ratio of an average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0 is provided.
Further, according to the present invention, the conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin, wherein the primary particles of the conductive carbon black are contained in the styrene resin. A plurality of aggregated aggregates are contained, and the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates have an average value of the longest diameter of (i) 180 to 500 nm,
(Ii) A styrenic resin foam particle is provided having a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0.
Furthermore, according to the present invention, the conductive carbon black is composed of a plurality of foamed particles including a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin and fused to each other. Primary particles are contained as a plurality of aggregates in the styrenic resin, wherein the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates are (i) a maximum of 180 to 500 nm There is provided a styrenic resin foam molded article having an average value of the major diameter and (ii) a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0.
Furthermore, according to the present invention, it comprises the above-mentioned styrenic resin foam-molded article, and comprises the styrenic monomer, ethylbenzene, isopropylbenzene, normal propyl benzene, xylene, toluene, benzene in the styrenic resin foam-molded article. Provided is a thermal insulation material for living space, wherein the total content of aromatic organic compounds is less than 2000 ppm.
Further, according to the present invention, there is provided a method for producing the above-mentioned styrenic resin foamable particles, wherein seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and styrenic resin are dispersed in water. A step of impregnating the seed particles with the styrenic monomer in the dispersion liquid dispersed in the step of polymerizing the styrenic monomer simultaneously with or after the impregnation, and simultaneously or after the polymerization There is provided a method for producing styrenic resin foamable particles, comprising the steps of: impregnating with a blowing agent.
Furthermore, according to the present invention, there is provided a method for producing the above-mentioned styrenic resin foamable particles, which comprises the steps of melt-kneading conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and styrenic resin A styrenic resin comprising the steps of: injecting a foaming agent into the molten resin obtained in the melt-kneading step; and extruding the molten resin obtained in the foaming agent injection step into a liquid, cutting it, and then solidifying it. A method of producing expandable particles is provided.

  According to the present invention, a styrenic resin foam molding excellent in heat insulation and a heat insulating material for living space, styrenic resin foamable particles and foam particles for producing the above foam molded body, and styrenic resin foamable particles Can provide a manufacturing method of

In any of the following cases, it is possible to provide styrenic resin foamable particles for producing a styrenic resin foamable molded article which is more excellent in heat insulation.
(1) Primary particles of conductive carbon black are contained as an aggregate in which a plurality of aggregates are aggregated in a styrenic resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates are (i) 180 Having an average value of the longest diameter of -500 nm and a ratio of the average value of the longest diameter to the average primary particle diameter of (ii) 4.0-10.0;
(2) The conductive carbon black is acetylene black, ketjen black or a mixture thereof.
(3) The conductive carbon black has a specific surface area of 10 to 3000 m ² / g.

Further, in any of the following cases, it is possible to provide a styrene resin foamed particle for producing a styrene resin foamable molded article which is more excellent in heat insulation.
(1) Primary particles of conductive carbon black are contained as an aggregate in which a plurality of aggregates are aggregated in a styrenic resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates are (i) 180 Having an average value of the longest diameter of -500 nm and a ratio of the average value of the longest diameter to the average primary particle diameter of (ii) 4.0-10.0;
(2) The conductive carbon black is acetylene black, ketjen black or a mixture thereof;
(3) The expanded styrene resin particles have an average cell diameter of 150 to 350 μm.
(4) The conductive carbon black has a specific surface area of 10 to 3000 m ² / g.

Furthermore, in any of the following cases, it is possible to provide a styrenic resin foamable molded article which is more excellent in heat insulation.
(1) Primary particles of conductive carbon black are contained as an aggregate in which a plurality of aggregates are aggregated in a styrenic resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates are (i) 180 Having an average value of the longest diameter of -500 nm and a ratio of the average value of the longest diameter to the average primary particle diameter of (ii) 4.0-10.0;
(2) The conductive carbon black is acetylene black, ketjen black or a mixture thereof;
(3) Styrene resin foam particles have an average cell diameter of 150 to 350 μm;
(4) The styrenic resin foam-molded article has the following formula: 31 ≦ ΔE ′ = L ^* + in the measurement of surface color difference based on JIS Z8729-2004 “Color display method-L ^* a ^* b ^* color system” Satisfy the relational expression represented by | a ^* | + | b ^* | ≦ 50 (wherein, ΔE ′ represents the degree of blackness, L ^* the lightness, and a ^* and b ^* the color coordinates);
(5) The styrene resin foam molded article contains 0.5 to 20 parts by mass of conductive carbon black with respect to 100 parts by mass of the styrene resin, and the absorbance at a wave number of 1000 cm ^-1 obtained by transmission method infrared analysis At A and absorbance B at a wavenumber of 500 cm ^-1 , a ratio A / B of 0.8 to 2.0 is exhibited;
(6) Absorbance B is 0.5 or more;
(7) The styrenic resin foam molded body has a density of 0.01 to 0.04 g / cm ³ ;
(8) The conductive carbon black has a specific surface area of 10 to 3000 m ² / g;
(9) The styrenic resin foam has a water absorption of less than 0.5 g / 100 cm ² ;
(10) The styrenic resin foam molded body further contains a flame retardant.

It is an electron micrograph of the conductive carbon black which formed the aggregate. 1 is an electron micrograph of a cross section of a foam molded article of Example 1. FIG. 5 is an electron micrograph of a cross section of the foamed particles of Example 2.

(Styrenic resin foamable particles)
The styrene resin foamable particles (hereinafter, foamable particles) contain a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less, a styrene resin, and a foaming agent.

(1) Conductive Carbon Black Conductive carbon black has a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less. When the volume resistivity is higher than 1.0 × 10 ⁴ Ω · cm, the heat insulation may not be sufficiently improved. The preferable volume resistivity is 7.0 × 10 ³ Ω · cm or less, the more preferable volume resistivity is 4.0 × 10 ³ Ω · cm or less, and the more preferable volume resistivity is 2.0 × 10 ³ Ω Cm or less, and the most preferable volume resistivity is 1.0 × 10 ³ Ω · cm or less. Although the lower limit value of the volume resistivity is not particularly provided, it is, for example, about 1.0 × 10 ⁻¹ Ω · cm or more. As a specific value of volume resistivity, 1.0 × 10 ³ , 2.0 × 10 ³ , 3.0 × 10 ³ , 4.0 × 10 ³ , 5.0 × 10 ³ , 6.0 × 10 ³ , 7.0 × 10 ³ , 8.0 × 10 ³ , 9.0 × 10 ³ , 1.0 × 10 ⁴ Ω · cm and the like can be mentioned.

  Here, the volume resistivity refers to the raw material carbon black or the raw material carbon black as a masterbatch, foamable particles, foam particles, and a masterbatch, foamable particles, when it is added to a foam molded product, Melt-knead the expanded particles and carbon black taken out by removing the styrenic resin in the expanded molded product with an organic solvent with a polyethylene resin or polystyrene resin (carbon black: polyethylene resin or polystyrene resin = 1 : 4 (mass ratio)) means a value obtained by measuring the surface of a plate-like compact of a kneaded material. Detailed volume resistivity measurement methods are described in the examples.

In addition, even if it uses any of a polyethylene-type resin and a polystyrene-type resin, a volume resistivity becomes a comparable value.
In addition, even if carbon black as a raw material is used, the volume resistivity can be obtained by using carbon black taken out by removing a masterbatch, foamable particles, foam particles, and styrenic resin in a foam molded product with an organic solvent. It is the same value.

  In addition, when measuring a volume resistivity using polystyrene resin, about the procedure which takes out carbon black by removing a masterbatch, foamable particle, foam particle, and styrene resin in a foaming molding with an organic solvent, Removal of styrenic resin is stopped midway when carbon black: polystyrene resin = 1: 4 (mass ratio), or polystyrene black such that carbon black: polystyrene resin = 1: 4 (mass ratio) You may take the method of adding (diluting) resin. When the method of stopping the removal of the styrenic resin is adopted, in order to adjust to carbon black: polystyrene resin = 1: 4 (mass ratio), masterbatch, foamable particles, foam particles, carbon in the foam molded body The black amount may be measured or the styrene resin amount may be measured. The method for measuring the amount of carbon black is not particularly limited, and examples thereof include a method using a differential thermal-thermal-weight simultaneous measuring device.

The conductive carbon black may be contained in a form in which primary particles of conductive carbon black are dispersed in a styrenic resin, or an aggregate in which a plurality of primary particles of conductive carbon black are aggregated in styrenic resin It may be contained in the form of Preferably, the primary particles of the conductive carbon black are contained as a plurality of aggregates in the styrenic resin.
FIG. 1 shows an example of conductive carbon black in which aggregates are observed using an electron microscope. By primary particles of conductive carbon black is meant each of the generally circular particles as observed in FIG. Agglomerate means a mass of primary particles in which at least two substantially circular primary particles appear to overlap, as observed in FIG.

The primary particles preferably have an average primary particle size of 18 to 125 nm.
The average primary particle size means an average value of the longest diameter of primary particles, and can take a value of 18 to 125 nm. However, this does not restrict that the primary particles have a shape other than spherical and substantially spherical, and the primary particles may have other shapes such as cylindrical and prismatic. In the case where the primary particles have a shape other than a spherical shape and a substantially spherical shape, the average primary particle diameter means an average value of the longest diameters obtained by approximating the primary particles into a spherical shape. When the average primary particle size is less than 18 nm, the formability may be reduced due to the miniaturization of the bubbles, and when it is more than 125 nm, the formability may be reduced due to breakage of the cell membrane. Specific numerical ranges of the average primary particle diameter are 18 to 120 nm, 18 to 110 nm, 18 to 100 nm, 18 to 90 nm, 18 to 80 nm, 18 to 73 nm, 18 to 66 nm, 18 to 60 nm, 20 to 100 nm, 25 80 nm, 32 to 66 nm, 20 to 125 nm, 25 to 125 nm, 32 to 125 nm, 40 to 125 nm, 50 to 125 nm, 60 to 125 nm, 66 to 125 nm, 73 to 125 nm, 80 to 125 nm, and the like. Specific values of the average primary particle diameter include 18, 20, 25, 32, 40, 50, 60, 66, 73, 80, 90, 100, 110, 120, 125 nm and the like.

The agglomerates preferably have an average value of (i) the longest diameter of 180 to 500 nm.
The longest diameter means the longest one of the distances between any two points on the outer edge of the aggregate, and in FIG. 1, for example, the diameter indicated by the solid line is defined as the longest diameter of the aggregate . When the average value of the longest diameter is less than 180 nm, the heat insulation may not be improved, and when it is larger than 500 nm, the air bubbles may be broken at the time of foaming and the heat insulation may not be improved to obtain a good molded product. The specific numerical range of the average value of the longest diameter is 180 to 450 nm, 180 to 400 nm, 180 to 370 nm, 180 to 300 nm, 180 to 240 nm, 200 to 450 nm, 220 to 400 nm, 240 to 370 nm, 200 to 500 nm, 220-500 nm, 240-500 nm, 300-500 nm, 370-500 nm, 400-500 nm etc. are mentioned. Specific average values of the longest diameter include 180, 200, 220, 230, 240, 250, 300, 350, 370, 400, 420, 450, 460, 470, 480, 490, 500 nm and the like.
The longest diameter of the aggregate is set so as to always overlap with the aggregate. That is, it is assumed that the longest diameter does not pass through the background (styrene resin). For example, in FIG. 1, the line indicated by the broken line can not be set as the longest diameter because it has a portion overlapping with the background.

  Also, the aggregate preferably has a ratio of “average value of longest diameter” to “average primary particle diameter” of (ii) 4.0 to 10.0. If the above ratio is less than 4.0, the heat insulation may not be improved, and if it is more than 10.0, air bubbles may be broken during foaming, and a good molded product may not be obtained. As a specific numerical range of said ratio, 4.0-9.0, 5.0-9.0, 5.0-8.9, 5.0-8.5, 5.0-8. 0, 5.0 to 7.0, 5.0 to 6.0, 5.2 to 8.9, 5.5 to 8.5, 6.0 to 8.0, 4.0 to 10.0, 5.0-10.0, 5.2-10.0, 5.5-10.0, 6.0-10.0 etc. are mentioned. As specific values of the ratio of the average value of the longest diameter to the average primary particle diameter, 4.0, 4.5, 5.0, 5.2, 5.5, 6.0, 7.0, 8. 0, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0 and the like. Detailed average values of the longest diameter and methods of measuring the average primary particle diameter are described in the examples.

  The conductive carbon black is not particularly limited as long as it has the above-mentioned volume resistivity, and examples thereof include acetylene black, ketjen black, carbon nanofibers, carbon nanotubes and the like.

  The content of the conductive carbon black is 0.5 to 25 parts by mass with respect to 100 parts by mass of the styrene resin. If the content is less than 0.5 parts by mass, the heat insulation may not be sufficiently improved. On the other hand, when the content is more than 25 parts by mass, the foamability may be lowered due to tearing of the foam film, resulting in poor heat insulation. The content of the conductive carbon black is preferably 0.5 to 15 parts by mass, and the content of the conductive carbon black is more preferably 0.5 to 10 parts by mass. The specific content is 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.01, 2, 2.56, 3, 3.13, 4, 5, 5.26, 6, 7, 7, 7.52, 7.69, 8, 9, 10, 11, 11. 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. Be

The conductive carbon black preferably has a specific surface area of 10 to 3000 m ² / g. If the specific surface area is less than 10 m ² / g, the desired heat insulation performance may not be obtained. On the other hand, when the specific surface area exceeds 3000 m ² / g, the workability may be reduced. For example, as a specific numerical range of the specific surface ^{area, 100~3000m 2 / g, 200~3000m 2} / g, 210~3000m 2 / g, 220~3000m 2 / g, 15~2500m 2 / g, 100~ ^{2500m 2 / g, 210~2500m 2 /} g, 10~2000m 2 / g, 60~2000m 2 / g, 210~2000m 2 / g, 10~1500m 2 / g, 70~1500m 2 / g, 200~1500m ² / g, 210-1500 m < ² > / g etc. are mentioned. When the conductive carbon black is acetylene black, a more preferable specific surface area is 20 to 300 m ² / g. When the conductive carbon black is ketjen black, a more preferable specific surface area is 500 to 2000 m ² / g. Specific values of specific surface area are 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 400, 500, 700, 1000, 1500, 2000, 2500, 3000 m < ² > / g etc. are mentioned.

  When the conductive carbon black is acetylene black or ketjen black, preferable physical property values other than those described above include the following.

(2) Styrene-based resin The styrene-based resin is not particularly limited as long as it is a resin that can obtain a foam-molded product. For example, styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, ethylstyrene, i-propylstyrene, t-butylstyrene, dimethylstyrene, bromostyrene, chlorostyrene and the like, or a mixture of these monomers And resins derived from
The styrene resin may contain a component derived from a crosslinking agent.
As the crosslinking agent, for example, divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, bis (vinylphenyl) methane, bis (vinylphenyl) ethane, bis (vinylphenyl) propane, bis (vinylphenyl) butane, divinylnaphthalene , Divinyl anthracene, a compound in which a vinyl group is directly bonded to a polyfunctional benzene ring such as divinyl biphenyl, etc., diethylene oxide adduct of bisphenol A di (meth) acrylate, propylene oxide adduct of bisphenol A di (meth) acrylate A (meth) acrylate compound etc. are mentioned.

  The styrenic resin may be a copolymer of another monomer and the styrenic monomer in an amount that does not impair the characteristics of the present invention. Other monomers include, for example, (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cetyl (meth) acrylate and the like Esters, alkyl maleates such as (meth) acrylonitrile, dimethyl maleate, diethyl maleate, etc., dimethyl fumarate, alkyl fumarates such as diethyl fumarate, ethyl fumarate, maleic anhydride, N-phenyl maleimide, (meth) acrylic An acid etc. are mentioned.

Furthermore, resins other than the above may be included. As resins other than the above, rubber-modified with a diene rubber-like polymer such as polyolefin resin such as polyethylene and polypropylene, polybutadiene, styrene-butadiene copolymer, ethylene-propylene non-conjugated diene three-dimensional copolymer Impact-resistant polystyrene resins, polycarbonate resins, polyester resins, polyamide resins, polyphenylene ether, acrylonitrile-butadiene-styrene copolymer, polymethyl methacrylate and the like can be mentioned. The proportion of these other resins is preferably less than 50% by mass, more preferably 30% by mass or less, and still more preferably 10% by mass or less, based on the total amount of the base resin.
The styrene-based resin preferably has a weight average molecular weight of 100,000 to 1,000,000. If the weight average molecular weight is less than 100,000, the strength of the foam molded article may be reduced. If it is more than 1,000,000, the foamability may be reduced and the weight may be inferior. The weight average molecular weight is more preferably 150,000 to 800,000, and further preferably 200,000 to 500,000.

  The content of the styrenic resin in the expandable particles is preferably 50% by mass or more. If the amount is less than 50% by mass, sufficient foamability may not be obtained. A more preferable content rate is 60 mass% or more, and a further preferable content rate is 80 mass% or more.

(3) Blowing agent The blowing agent is not particularly limited, and any known one can be used. In particular, an organic compound having a boiling point equal to or lower than the softening point of the styrene resin and being gaseous or liquid at normal pressure is suitable. For example, hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, cyclopentadiene, n-hexane, petroleum ether, ketones such as acetone and methyl ethyl ketone, methanol, ethanol, isopropyl alcohol and the like Low-boiling ether compounds such as alcohols, dimethyl ether, diethyl ether, dipropyl ether and methyl ethyl ether, halogen-containing hydrocarbons such as trichloromonofluoromethane and dichlorodifluoromethane, and inorganic gases such as carbon dioxide gas, nitrogen and ammonia It can be mentioned. These foaming agents may be used alone or in combination of two or more. Among them, it is preferable to use a hydrocarbon from the viewpoint of preventing the destruction of the ozone layer and in the viewpoint of rapidly replacing with air and suppressing the temporal change of the foam molded article. Among hydrocarbons, hydrocarbons having a boiling point of −45 to 40 ° C. are more preferable, and propane, n-butane, isobutane, n-pentane, isopentane and the like are further preferable.
The content of the blowing agent is preferably in the range of 2 to 12% by mass. When the amount is less than 2% by mass, a foam molded article having a desired density may not be obtained. In addition, since the effect of enhancing the secondary foaming power at the time of in-mold foam molding is reduced, the appearance of the foam molded article may not be good. When the content is more than 12% by mass, the time required for the cooling step in the production process of the foam molded product may be prolonged, and the productivity may be lowered. The more preferable content is 3 to 10% by mass, the more preferable content is 4 to 9% by mass, and the most preferable content is 5 to 8% by mass.
A blowing aid may be used in combination with the blowing agent. As a foaming aid, isobutyl adipate, toluene, cyclohexane, ethylbenzene and the like can be mentioned.

(4) Other Additives The foamable particles may contain other additives as needed. Other additives include plasticizers, flame retardants, flame retardant aids, antistatic agents, spreading agents, cell regulators, fillers, colorants, weathering agents, anti-aging agents, lubricants, anti-fogging agents, and fragrances. Etc.
As the plasticizer, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as cyclohexane, hexane and heptane, etc., adipic acid esters such as diisobutyl adipate, dioctyl adipate and diisononyl adipate, glycerin diacetomonolaurate And glycerin fatty acid esters such as dioctyl phthalate, diisononyl phthalate, phthalic acid esters such as diisobutyl phthalate, and high boiling compounds such as liquid paraffin and white oil.

As a flame retardant, tetrabromocyclooctane, hexabromocyclododecane, trisdibromopropyl phosphate, tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether) and the like.
The flame retardant auxiliary includes 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, dicumyl peroxide, and organic peroxide of cumene hydroperoxide. .
Examples of the antistatic agent include polyoxyethylene alkylphenol ether, stearic acid monoglyceride, polyethylene glycol and the like.
As the spreading agent, polybutene, polyethylene glycol, glycerin, silicone oil and the like can be mentioned.

As a foam control agent, talc, mica, silica, diatomaceous earth, aluminum oxide, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, Metal sulfate such as barium sulfate, glass beads, polytetrafluoroethylene, tribasic calcium phosphate, magnesium pyrophosphate, zinc stearate, magnesium stearate, bisamide compounds such as ethylenebisstearic acid amide, methylenebisstearic acid amide, stearic acid amide And amide compounds such as 12-hydroxystearic acid amide, fatty acid glycerides such as stearic acid triglyceride and stearic acid monoglyceride, and the like.
Examples of the lubricant include metal soaps such as zinc stearate and magnesium stearate, bisamide compounds such as ethylenebisstearic acid amide and methylenebisstearic acid amide, amide compounds such as stearic acid amide and 12-hydroxystearic acid amide, stearic acid triglyceride, Stearic acid monoglycerides, fatty acid glycerides such as hydroxystearic acid triglyceride, polyethylene wax, liquid paraffin, white oil and the like can be mentioned.

(5) Method for Producing Expandable Particles The scope of the present invention also includes the method for producing expandable particles described above.
In one embodiment of the invention:
In the dispersion liquid obtained by dispersing seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrenic resin in an aqueous medium, the styrenic monomer is used as the seed particles Impregnating the
Simultaneously with or after the impregnation, a step of polymerizing the styrenic monomer;
Simultaneously with or after the polymerization, the step of impregnating the blowing agent is provided. A method for producing styrenic resin foamable particles is provided.

The aqueous medium is not particularly limited as long as it is a liquid that can dissolve a water-soluble substance at normal temperature, and water, lower alcohols having 1 to 4 carbon atoms, and mixtures thereof can be mentioned, with water being particularly preferable. The amount of use of the aqueous medium can be appropriately set by those skilled in the art.
The resin obtained by polymerization may contain a resin other than the styrene resin. The type, physical properties and content of such a resin are as described above.

  This embodiment is an embodiment of producing expandable particles using a suspension polymerization method which is one of the representative methods of producing expandable particles in the art. Hereinafter, the suspension polymerization method will be described in more detail, but the present embodiment is not limited to the conditions and the like described below.

1. Suspension polymerization method In suspension polymerization method, the polymerization initiator is dissolved in styrene monomer, and the temperature is raised and polymerized in the reaction tank together with the water in which the suspending agent is dispersed, and then cooled, the styrene resin foamable particles How to get The method of adding the foaming agent during and / or after the polymerization is called a one-stage method. The particles obtained by polymerization without adding a foaming agent are sieved and only particles of the necessary particle size range are heated in water in which the suspending agent of the reaction tank is dispersed, and the foaming agent is added here The method of impregnating the particles is called a two-stage method (post-impregnation method). In addition, polystyrene particles (seed particles) of small particles are charged into a reaction tank containing water in which a suspending agent is dispersed, and the temperature is raised, and then a styrene monomer in which a polymerization initiator is dissolved is continuously The method of supplying, polymerizing and growing to the target particle size is called seed polymerization. In the seed polymerization method, the blowing agent is added during and / or after the polymerization. The styrenic resin foamable particles of the present invention can be produced by any of a one-step method, a two-step method (post-impregnation method), and a seed polymerization method. In addition, there is an advantage that spherical expandable particles can be obtained by any method. As a preferred production method, a seed polymerization method can be mentioned. According to the seed polymerization method, polystyrene particles (master batch) containing conductive carbon black in high concentration (for example, 20% by mass) can be used as seed particles, and there is an advantage that polymerization inhibition hardly occurs.

Hereinafter, the seed polymerization method of the suspension polymerization method will be described in more detail, but the present embodiment is not limited to the conditions and the like described below.
(A) Seed polymerization method of suspension polymerization method As this method, a styrene-based resin particle is obtained by causing a styrene-based monomer to be absorbed and polymerized in a seed particle containing conductive carbon black and a styrene-based resin. A method of obtaining expandable particles by injecting a foaming agent during and / or after the polymerization is mentioned. In this method, foamable particles containing a large amount of conductive carbon black at the center can be easily obtained.

(I) Seed particle The seed particle may be produced by a known method. For example, after conducting melt-kneading of conductive carbon black and styrenic resin with an extruder, it is extruded in the form of a strand and the strand is cut. And extrusion methods for obtaining seed particles. Moreover, resin particle | grains can be used for seed particle | grains in part or all. In the case of using a recovered product, production of seed particles by an extrusion method is suitable.
The average particle size of the seed particles can be appropriately adjusted according to the average particle size of the resin particles. Furthermore, the weight average molecular weight of the seed particles is not particularly limited, but is preferably 100,000 to 500,000, and more preferably 150,000 to 400,000.

  The addition amount of the conductive carbon black is 0.5 to 25 parts by mass with respect to a total of 100 parts by mass of the addition amount of the styrene resin and the styrene monomer in the seed particles. That is, the seed particles are added such that the amount of conductive carbon black added is 0.5 to 25 parts by mass. When the addition amount is less than 0.5 parts by mass, the heat insulation may not be sufficiently improved. On the other hand, when the addition amount exceeds 25 parts by mass, the foamability may be lowered due to tearing of the foam film, resulting in poor heat insulation. The addition amount of the conductive carbon black is preferably 0.5 to 15 parts by mass, and the addition amount of the conductive carbon black is more preferably 0.5 to 10 parts by mass. The specific addition amount is 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.01, 2, 2.56, 3, 3.13, 4, 5, 5.26, 6, 7, 7, 7.52, 7.69, 8, 9, 10, 11, 11. 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. Be The addition amount may be adjusted to be substantially the same as the content described for the foamable particles.

(Ii) Polymerization step In the dispersion obtained by dispersing the seed particles in an aqueous medium, the monomer mixture is supplied to absorb the respective monomers into the seed particles, and then the respective monomers are polymerized. Styrene resin particles can be obtained.
It is preferable that the addition amount of a styrene-type monomer is 50 mass parts or more with respect to a total of 100 mass parts of addition amount of a seed particle and a styrene-type monomer. If the amount is less than 50 parts by mass, sufficient foamability may not be obtained. A more preferable content rate is 60 parts by mass or more, and a further preferable content rate is 80 parts by mass or more. The addition amount may be adjusted to be substantially the same as the content described for the foamable particles.
The aqueous medium includes water, and a mixed medium of water and a water-soluble solvent (eg, alcohol).

  Each monomer to be used may contain a polymerization initiator. The polymerization initiator is not particularly limited as long as it is conventionally used for polymerizing monomers. For example, benzoyl peroxide, t-butylperoxybenzoate, t-butylperoxy-2-ethylhexanoate, lauryl peroxide, t-butylperoxide, t-butylperoxypivalate, t-butylperoxyisopropyl Carbonate, t-butyl peroxy acetate, 2,2-t-butyl peroxy butane, t-butyl peroxy-3,3,5-trimethylhexanoate, di-t-butyl peroxy hexahydroterephthalate, 2 ,, Organic peroxides such as 5-dimethyl-2,5-di (benzoylperoxy) hexane and dicumyl peroxide; azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile; and the like. Among these initiators, in order to reduce the residual monomer, two or more different polymerization initiators having a decomposition temperature of 80 to 120 ° C. may be used in combination to obtain a half life of 10 hours. The polymerization initiator may be used alone or in combination of two or more.

  The aqueous medium may contain a suspension stabilizer to stabilize the dispersion of monomer droplets and seed particles. The suspension stabilizer is not particularly limited as long as it is conventionally used for suspension polymerization of monomers. Examples thereof include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide and polyvinyl pyrrolidone, and slightly soluble inorganic compounds such as calcium triphosphate, magnesium pyrophosphate, magnesium oxide and hydroxyapatite. And when using a poorly soluble inorganic compound as said suspension stabilizer, it is preferable to use together anionic surfactant, As such anionic surfactant, fatty acid soap, N-acyl amino acid or its Salts, carboxylates such as alkyl ether carboxylates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinic acid esters, sulfonates such as alkyl sulfoacetates, α-olefin sulfonates, etc .; higher alcohol sulfuric acid Ester salts, secondary higher alcohol sulfuric acid ester salts, alkyl ether sulfates, sulfuric acid ester salts such as polyoxyethylene alkylphenyl ether sulfates; alkyl ether phosphoric acid ester salts, phosphoric acid ester salts such as alkyl phosphoric acid ester salts, etc. Can be mentioned.

  The polymerization step differs depending on the type of monomer used, the type of polymerization initiator, the polymerization atmosphere, etc., but is usually carried out by maintaining heating at 70 to 130 ° C. for 3 to 10 hours. The polymerization step may be performed while impregnating the monomer. In the polymerization step, the total amount of monomers to be used may be polymerized in one step, or may be divided into two or more steps and polymerized (including the polymerization at the time of production of seed particles).

(Iii) Foaming agent impregnation step The foamable particles can be obtained by impregnating the above-mentioned styrenic resin particles with a foaming agent.
The impregnation may be performed wet simultaneously with the polymerization, or may be performed wet or dry after the polymerization. When it is carried out in a wet manner, it may be carried out in the presence of a suspension stabilizer and a surfactant as exemplified in the above-mentioned polymerization step. As for the impregnating temperature of a foaming agent, 60-120 ° C is preferred. When the temperature is lower than 60 ° C., the time required for impregnating the resin particles with the foaming agent may be long, which may lower the production efficiency. When the temperature is higher than 120 ° C., the resin particles may be fused to generate bonded particles. A more preferred impregnation temperature is 70 to 110 ° C.

  The amount of the foaming agent to be impregnated is preferably in the range of 2 to 12 parts by mass with respect to 100 parts by mass of the styrenic resin obtained by polymerization. If the amount is less than 2 parts by mass, a foam having a desired density may not be obtained from the foamable particles. In addition, since the effect of enhancing the secondary foaming power at the time of in-mold foam molding is reduced, the appearance of the foam molded article may not be good. If the amount is more than 12 parts by mass, the time required for the cooling step in the process of producing the foam molded product may be prolonged, and the productivity may be lowered. The more preferable content is 3 to 10 parts by mass, the more preferable content is 4 to 9 parts by mass, and the most preferable content is 5 to 8 parts by mass. The amount of the foaming agent to be impregnated may be adjusted to be approximately the same as the content described for the expandable particles. Further, as described above, a foaming aid may be used in combination with a foaming agent. The type and the like of the foaming aid are as described above, and the addition amount can be appropriately set by those skilled in the art.

In another embodiment of the invention:
Melt-kneading a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin,
Injecting a foaming agent into the molten resin obtained in the melt-kneading step;
The process for producing styrenic resin foamable particles is provided, which comprises the steps of: extruding the molten resin obtained in the blowing agent injection step into a liquid, cutting it, and then solidifying it.

  This embodiment is an embodiment in which expandable particles are produced using a melt extrusion method which is one of the representative methods for producing expandable particles in the art. Hereinafter, the melt extrusion method will be described in more detail, but the present embodiment is not limited to the conditions and the like described below.

2. Melt Extrusion Method In the melt extrusion method, polystyrene pellets are supplied to a resin supply device, and a foaming agent is pressed into and kneaded with a polystyrene resin melted in the resin supply device, and the molten resin containing the foaming agent is tipped at the resin supply device It is a method of extruding from the small holes of the die attached to and then cooling to obtain styrenic resin expandable particles. The method of extruding directly from the small holes of the die into a cooling liquid, cutting the extrudate with a rotary blade immediately after extrusion, and cooling the cut particles in the cooling liquid is called a hot cut method. Once the strands of the die are extruded in the form of strands into air, introduced into a cooling water bath before the strands are foamed, and the strands are cooled in a cooling water bath and then cut into cylindrical particles by strand cutting. It is called the law (cold cut method). The styrenic resin foamable particles of the present invention can be produced by any of a hot cut method and a strand cut method (cold cut method). In addition, there is an advantage that any amount of conductive carbon black can be easily contained in the particles by any method. In addition, conductive carbon black can be uniformly contained in the expandable particles. A hot-cut method is mentioned as a preferable manufacturing method. The hot-cut method has an advantage that substantially spherical expandable particles can be obtained.

Hereinafter, although the hot-cut method of the melt extrusion method will be described in more detail, the present embodiment is not limited to the conditions and the like described below.
(B) Hot-cut method of melt extrusion method In this method, a foaming agent is pressed into and kneaded with a polystyrene resin melted in a resin supply device, and the molten resin containing the foaming agent is attached to the tip of the resin supply device The extruded material directly extruded from the small holes of the die into the cooling liquid, and the extruded product extruded into the cooling liquid is cut with a rotary blade in the cooling liquid, and the extrudate is cooled and solidified by contact with the liquid to foam Is a method of obtaining sexual particles.
In this method, for example, the following manufacturing apparatus can be used. That is, an extruder as a resin supply apparatus, a die having a large number of small holes attached to the tip of the extruder, a raw material supply hopper for charging the raw material into the extruder, and a blowing agent supply port for the molten resin in the extruder A high pressure pump for injecting a foaming agent through the hole, a cutting chamber provided with cooling water to be brought into contact with a resin discharge surface on which a small hole of the die is drilled, and a cooling chamber is circulated and supplied to the room. A cutter (a high-speed rotary blade) rotatably provided in the cutting chamber so as to cut the resin extruded from the mold, and foamable particles carried along with the flow of the cooling water from the cutting chamber are separated from the cooling water Dehydration dryer with solid-liquid separation function that dehydrates and dries to obtain foamable particles, water tank that stores cooling water separated by dehydrating dryer with solid-liquid separation function, and cutting chamber of cooling water in this water tank A high pressure pump to send, include manufacturing apparatus and a storage container for storing the dewatered dried effervescent grains at the solid-liquid separation function dehydrating dryer.

  An example of a procedure for producing expandable particles using the above-mentioned production apparatus will be described. First, raw materials polystyrene resin and carbon black are introduced into the extruder from the raw material feed hopper. The raw material polystyrene resin may be pelletized or granulated and well mixed in advance and then fed from one raw material feed hopper or, for example, when using a plurality of lots, the feed amount for each lot is used. It is possible to charge from a plurality of adjusted raw material feed hoppers and mix them in the extruder. In addition, when using a plurality of lots of recycled materials in combination, the materials of the plurality of lots are well mixed in advance, and foreign substances are removed by appropriate sorting means such as magnetic sorting, sieving, specific gravity sorting, air blast sorting, etc. It is preferable to keep it. The carbon black may be introduced into the extruder as a master batch prepared by melt mixing with a polystyrene resin in advance.

  The addition amount of the conductive carbon black is 0.5 to 25 parts by mass with respect to 100 parts by mass of the addition amount of the styrene resin. When the addition amount is less than 0.5 parts by mass, the heat insulation may not be sufficiently improved. On the other hand, when the addition amount exceeds 25 parts by mass, the foamability may be lowered due to tearing of the foam film, resulting in poor heat insulation. The addition amount of the conductive carbon black is preferably 0.5 to 15 parts by mass, and the addition amount of the conductive carbon black is more preferably 0.5 to 10 parts by mass. The specific addition amount is 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.01, 2, 2.56, 3, 3.13, 4, 5, 5.26, 6, 7, 7, 7.52, 7.69, 8, 9, 10, 11, 11. 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. Be The addition amount may be adjusted to be substantially the same as the content described for the foamable particles.

  After the raw material is supplied into the extruder, the polystyrene resin is heated and melted, and while the molten resin is transferred to the die side, the foaming agent is pressed in from the foaming agent supply port by a high pressure pump to mix the foaming agent with the molten resin, The melt is moved to the tip side while kneading it further through a screen for removing foreign substances, which is optionally provided in the extruder, and the melt to which the foaming agent is added is extruded from the small holes of the die attached to the tip of the extruder. .

  The conditions for injection of the foaming agent into the molten resin obtained by melt-kneading can be set appropriately by those skilled in the art. The amount of the foaming agent added is preferably in the range of 2 to 12 parts by mass with respect to 100 parts by mass of the molten resin. If the amount is less than 2 parts by mass, a foam having a desired density may not be obtained from the foamable particles. In addition, since the effect of enhancing the secondary foaming power at the time of in-mold foam molding is reduced, the appearance of the foam molded article may not be good. If the amount is more than 12 parts by mass, the time required for the cooling step in the process of producing the foam molded product may be prolonged, and the productivity may be lowered. The more preferable content is 3 to 10 parts by mass, the more preferable content is 4 to 9 parts by mass, and the most preferable content is 5 to 8 parts by mass. In addition, the quantity of the blowing agent to inject | poure can be adjusted so that it may become a value substantially the same as the content described about the foamable particle | grain. Further, as described above, a foaming aid may be used in combination with a foaming agent. The type of the foaming aid is as described above, and the amount of the foaming aid to be added can be appropriately set by those skilled in the art.

The resin discharge surface where the small holes of the die are bored is disposed in the cutting chamber to which the cooling water is circulated and supplied into the chamber, and the cutter which can cut the resin pushed out from the small holes of the die into the cutting chamber Are provided rotatably. When the melt added with a foaming agent is extruded from the small holes of a die attached to the tip of the extruder, the melt is cut into particles, and simultaneously contacted with cooling water and quenched to solidify while suppressing foaming. It becomes effervescent particles.
The formed expandable particles are carried from the cutting chamber into the flow of cooling water and carried to the dehydrating dryer with solid-liquid separation function, where the expandable particles are separated from the cooling water and dewatered to dryness. The dried expandable particles are stored in a storage container.
In addition, when adding a flame retardant, although addition time is not specifically limited, Preferably it is added to an extruder with a raw material.

3. Other Methods As an example of another method, in the melt extrusion method, styrene resin particles are obtained without pressure injection of a foaming agent, and then the particles are expanded by a two-stage method (post-impregnation method) of suspension polymerization method And a method of producing styrenic resin foamable particles by using the particles as seed particles and seed polymerization method of suspension polymerization method. Also by these methods, the styrene resin foamable particles of the present invention can be produced. Moreover, there is an advantage that any amount of conductive carbon black can be easily contained in the particles by the melt extrusion method by any method. A preferable production method is a method of producing styrenic resin foamable particles by seed polymerization using the particles as seed particles after obtaining particles not containing a foaming agent by melt extrusion. According to this method, polystyrene particles (master batch) containing conductive carbon black in a high concentration (for example, 20% by mass) can be used as seed particles, and there is an advantage that polymerization inhibition is less likely to occur. There is an advantage that foamable particles can be obtained.

(Styrene resin foam particles)
The styrene resin foam particles (hereinafter, foam particles) contain conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin. The foam particles can be obtained by foaming (pre-foaming) the foamable particles, and correspond to pre-foamed particles for producing the following foam molded article.
The conductive carbon black and the styrenic resin that constitute the expanded particles are the same as the expandable particles.

The expanded particles preferably have a bulk density of 0.009 to 0.400 g / cm ³ . If the bulk density is more than 0.400 g / cm ³ , the weight of the foam molded article may be reduced. If the bulk density is less than 0.009 g / cm ³ , the heat insulation performance and mechanical strength of the foam molded article may be reduced. More preferable bulk density is 0.010 to 0.100 g / cm ³ , still more preferable bulk density is 0.01 to 0.04 g / cm ³ , and further preferable bulk density is 0.011 to 0.032 g / cm ^3. It is cm ³ and the most preferred bulk density is 0.014 to 0.029 g / cm ³ . Specific bulk density values are 0.009, 0.010, 0.011, 0.012, 0.0125, 0.013, 0.014, 0.015, 0.02, 0.03, and so on. It may be 0.033, 0.035, 0.04, 0.1, 0.2, 0.3, 0.4 g / cm ³ or the like.

  It is preferable that the average diameter (average cell diameter) of the foam | bubble which comprises foaming particle | grains is 50-1000 micrometers. If the average cell diameter is less than 50 μm, the heat insulation may be reduced. When the average cell diameter is larger than 1000 μm, mechanical strength may be reduced. As for an average bubble diameter, 100-600 micrometers is more preferable, and 200-300 micrometers is still more preferable. Specific values of the average cell diameter may be 50, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000 μm and the like.

The expanded particles are obtained by expanding expandable particles to a desired bulk density using water vapor or the like.
The expanded particles may be aged, for example at normal pressure, prior to the subsequent foam molding process. The ripening temperature of the foamed particles is preferably 20 to 60 ° C. When the aging temperature is low, the aging time of the foamed particles may be long. On the other hand, when it is high, the foaming agent in the foamed particles may be dissipated to deteriorate the formability.

(Styrenic resin foam molding)
A styrenic resin foam molded article (hereinafter referred to as a foam molded article) contains conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrenic resin, and a plurality of foam particles fused together It is configured. This foamed molded article can be obtained by subjecting the foamed particles to foam molding.
The conductive carbon black and the styrenic resin constituting the foamed molded article are the same as the above-described expandable particles.

Preferably, the foamed molded article is the following formula in surface color difference measurement based on JIS Z8729-2004 "Color display method-L ^* a ^* b ^* color system":
31 ≦ ΔE ′ = L ^* + | a ^* | + | b ^* | ≦ 50
(Wherein, ΔE ′ represents the degree of blackness, L ^* the lightness, a ^* and b ^* the color coordinates)
Satisfy the relational expression shown in More preferable ΔE ′ is 32 ≦ ΔE ′ ≦ 45, and a further preferable ΔE ′ is 32 ≦ ΔE ′ ≦ 35. In the case of ΔE ′ <31, the heat insulation may decrease. On the other hand, when ΔE ′> 50, the heat insulation may decrease. (1) To make ΔE ′ small, select a carbon black closer to black, increase the carbon black content in the foam, increase the density of the foam, etc. Can be achieved. (2) In order to make ΔE ′ a large value, it is necessary to select carbon black closer to gray, reduce the content of carbon black in the foam molded body, lower the density of the foam molded body, etc. Can be achieved. Specific values of the degree of blackness include 31, 32, 33, 34, 35, 38, 40, 43, 44, 45, 46, 47, 48, 49, 50 and the like. The detailed method of measuring the degree of blackness is described in the examples.

  The foam may further contain a flame retardant. As the flame retardant, the same ones as described above for the expandable particles can be used, but tetrabromocyclooctane or tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) is particularly preferable. preferable. The content of the flame retardant is 0.5 to 10 parts by mass, preferably 2 to 8 parts by mass with respect to 100 parts by mass of the foam molded article. As a value of content of a flame retardant, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10 mass parts etc. are mentioned.

  Preferably, the foam molded body is a heat insulating material for a living space having a total content of an aromatic organic compound consisting of a styrenic monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene and benzene is less than 2000 ppm. If the total content of the aromatic organic compound is less than 2000 ppm, it is possible to cope with the sick house syndrome which has been requested in recent years, and a more comfortable living space can be provided. More preferably, it is 1750 ppm or less, still more preferably 1500 ppm or less, most preferably 500 ppm or less, and most preferably 300 ppm or less. During the manufacturing process, select resin raw materials with low content of aromatic organic compounds consisting of styrenic monomers, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene and benzene as polystyrene-based resins that are raw materials Thus, styrenic resin foamable particles, foam particles, a foam molded article and a heat insulating material for a living space can be obtained without mixing the aromatic organic compound. In the case of the foamed particles, the foamed molded article, and the heat insulating material for a living space obtained from the same styrenic resin foamable particles, the total content of the aromatic organic compound has a similar value. The styrenic resin foamable particles having a total content of the aromatic organic compound of less than 2000 ppm are suitable for producing a heat insulating material for living space. Moreover, as a manufacturing method to obtain styrenic resin foamable particles having a small total content of the aromatic organic compound, a melt extrusion method is preferable. A detailed method of measuring the total content of aromatic organic compounds is described in the examples.

The foamed molded article preferably has a density of 0.010 to 0.400 g / cm ³ . When the density is more than 0.400 g / cm ³ , the lightness may be reduced. If the density is less than 0.010 g / cm ³ , the thermal insulation performance and the mechanical strength may be reduced. More preferred density is 0.011~0.100g / cm ^3, even more preferred density is 0.012~0.04g / cm ^3, more preferred density is 0.0125~0.033g / cm ³ There, the most preferred density is 0.015~0.030g / cm ^3. Specific bulk density values are 0.009, 0.010, 0.011, 0.012, 0.0125, 0.013, 0.014, 0.015, 0.02, 0.03, and so on. It may be 0.033, 0.035, 0.04, 0.1, 0.2, 0.3, 0.4 g / cm ³ or the like.

  The average diameter (average cell diameter) of the cells constituting the foam molded body is preferably 50 to 1000 μm. If the average cell diameter is less than 50 μm, the heat insulation may be reduced. When the average cell diameter is larger than 1000 μm, mechanical strength may be reduced. As for an average bubble diameter, 100-600 micrometers is more preferable, and 200-300 micrometers is still more preferable. Specific values of the average cell diameter may be 50, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000 μm and the like.

  The foam molded body preferably exhibits a thermal conductivity of 0.034 W / mk or less. If the thermal conductivity exceeds 0.034 W / mk, it may not be possible to provide a foam molded article having sufficient thermal insulation. A more preferable thermal conductivity is 0.033 W / mk or less, and a still more preferable thermal conductivity is 0.032 W / mk or less. Specific values of thermal conductivity are 0.034, 0.0339, 0.0338, 0.0337, 0.0336, 0.0335, 0.0334, 0.0333, 0.0332, 0.0331. , 0.033, 0.0329, 0.0328, 0.0327, 0.0326, 0.0325, 0.0324, 0.0323, 0.0322, 0.0321, 0.032, 0.032, 0, 019 .0318, 0.0317, 0.0316, 0.0315, 0.0314, 0.0313, 0.0312, 0.0311, 0.031, 0.0309, 0.0308, 0.0307, 0.0306 , 0.0305, 0.0304, 0.0303, 0.0302, 0.0301, 0.030, and the like.

The foamed molded article preferably exhibits a water absorption of less than 0.5 g / 100 cm ² . When the amount of water absorption exceeds 0.5 g / 100 cm ² , the heat insulation may decrease. The more preferable water absorption is less than 0.4 g / 100 cm ² , the still more preferable water absorption is less than 0.3 g / 100 cm ² , and the still more preferable water absorption is less than 0.2 g / 100 cm ² . Specific values of water absorption are 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, etc. Can be mentioned.

Preferably, the foam molded article exhibits a ratio A / B of 0.8 to 2.0 at an absorbance A at a wave number of 1000 cm ⁻¹ and an absorbance B at a wave number of 500 cm ⁻¹ obtained by transmission method infrared analysis. In the case of the absorbance ratio A / B <0.8 or in the case of the absorbance ratio A / B> 2.0, sufficient adiabaticity may not be obtained. (1) The absorbance ratio A / B can be reduced to a small value by increasing the amount of the infrared shielding agent. (2) The absorbance ratio A / B can be increased by increasing the addition amount of the infrared shielding agent, decreasing the cell diameter, or the like. More preferable absorbance ratio A / B is 0.81 to 1.80, and more preferable absorbance ratio A / B is 0.82 to 1.75. Specific values of the absorbance ratio A / B are 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.9, 0.95, 1.0, 1 .1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.75, 1.76, 1.77, 1.78, 1.79, 1.8 , 1.85, 1.9, 1.95, 2.0 and the like.

The absorbance A means the absorbance at a wave number of 1000 cm ⁻¹ obtained by transmission infrared analysis. Preferred absorbance A is 0.8 or more. When the absorbance A is less than 0.8, the heat insulation is poor. More preferably, the absorbance A is 0.95 or more. Specific values of absorbance A are 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, and 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99 etc. are mentioned.

Further, the absorbance B means the absorbance at a wave number of 500 cm ^-1 obtained by transmission method infrared analysis. The preferred absorbance B is 0.5 or more. When the absorbance B is less than 0.5, the adiabaticity decreases. More preferably, the absorbance B is 0.55 or more. As specific absorbance B values, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.65, 0.7 etc. are mentioned.
Detailed methods of measuring the absorbances A and B are described in the examples.

For example, the foamed molded product is filled with the foamed particles in a closed mold having a large number of small holes, heated and foamed with a heat medium (for example, pressurized steam etc.) to fill the voids between the foamed particles and It can manufacture by integrating by making it mutually fuse | fuse. At that time, the density of the foam molded body can be prepared, for example, by adjusting the filling amount of the pre-foamed particles in the mold.
The heating and foaming can be performed, for example, by heating for 5 to 50 seconds with a heat medium at 110 to 150 ° C. Under this condition, good fusion property of the foamed particles can be secured. More preferably, the heating foam molding can be performed by heating for 10 to 50 seconds with a molding steam pressure (gauge pressure) 0.06 to 0.08 MPa and a heating medium (for example, water vapor) at 90 to 120 ° C. .

  The foam molded article can be used in various applications where heat insulation is required. For example, thermal insulation for walls, thermal insulation for floors, thermal insulation for roofs, thermal insulation for automobiles, thermal insulation for hot water tanks, thermal insulation for piping, thermal insulation for solar systems, thermal insulation for water heaters, food and industrial products, etc. It can be used for containers, packing materials such as fish and agricultural products, filling materials, core materials for tatami mats, etc. The foamed molded article can have a shape suitable for these applications. In particular, it can be suitably used as a heat insulating material for living space such as a heat insulating material for wall, a heat insulating material for floor, a heat insulating material for roof, a heat insulating material for automobiles and the like.

EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto.
<Volume Resistivity of Carbon Black Measured Using Polyethylene-Based Resin>
When the volume resistivity here is the raw material carbon black or the raw material carbon black is added to the master batch, the foamable particles, the foam particles, or the foam molded product, the master batch, the foamable particles, Carbon black taken out by removing the foamed particles and the styrenic resin in the foamed molded product with toluene as an organic solvent is melt-kneaded with a polyethylene resin (carbon black: polyethylene resin = 1: 4 (mass ratio) )) Means the measured value of the surface of the plate-like compact of the kneaded material.
Specifically, a polyethylene-based resin and carbon black are sufficiently melt-kneaded using an extruder and formed into a film, which is measured by the method described in JIS K 6911: 1995 “General Test Method for Thermosetting Plastics”. Do. That is, using a test apparatus (advanced test digital ultra-high resistance / micro ammeter R8340 and resistance chamber R12702A), crimp the electrode with a load of about 30 N onto the sample sample and charge it for one minute at 500 V The value is measured and calculated by the following equation. Sample The sample has a width of 100 × a length of 100 × original thickness (10 or less) mm. After conditioning at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5% for 24 hours or more, measurement is performed at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5% as a test environment. The number of test pieces is five, and the average value is taken as the volume resistivity (Ω · cm) of carbon black.
^{ρv = (πd 2 / 4t)} × Rv
ρv: Volume resistivity (Ω · cm)
d: Outer diameter of inner circle of surface electrode (cm)
t: Thickness of test piece (cm)
Rv: Volume resistance (Ω)

<Volume Resistivity of Carbon Black Measured Using Polystyrene-Based Resin>
When the volume resistivity here is the raw material carbon black or the raw material carbon black is added to the master batch, the foamable particles, the foam particles, or the foam molded product, the master batch, the foamable particles, Carbon black taken out by removing the foamed particles and styrenic resin in the foamed molded product with toluene as an organic solvent is melt-kneaded with a polystyrene resin (carbon black: polystyrene resin = 1: 4 (mass ratio) )) Means the measured value of the surface of the plate-like compact of the kneaded material.
Specifically, a resistivity test of a plate-like compact of a mixture of carbon black and polystyrene resin (carbon black: polystyrene resin = 1: 4 (mass ratio)) by a 4-probe method of conductive plastic Measure according to the method (JIS K 7194). A test apparatus uses Mitsubishi Chemical make low resistivity meter Lorester GP MCP-T600, and a sample sample is made into width 80x length 50x original thickness (20 or less) mm. The sample is conditioned at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5% for 24 hours or more, and then measured at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5% as a test environment. The volume resistivity is calculated according to the following equation by measuring the resistance value at five measurement positions according to JIS K 7194 on the surface of the sample. The average value is taken as the volume resistivity (Ω · cm) of carbon black.
v v = V / I × RCF × t
ρv: Volume resistivity (Ω · cm)
V / I: Resistance (Ω)
RCF: Correction factor depending on measurement position and sample thickness t: Thickness of test piece (cm)

<Weight average molecular weight>
The weight average molecular weight means a polystyrene (PS) reduced average molecular weight measured using gel permeation chromatography (GPC). Specifically, 3 mg of a sample was allowed to stand and dissolved in 10 mL of tetrahydrofuran (THF) for 72 hours (complete dissolution), and the obtained solution was non-aqueous 0.45 μm Chromatodisc (13 N) manufactured by Kurashiki Spinning Co., Ltd. Filter and measure. The average molecular weight of the sample is determined from a standard polystyrene calibration curve which has been measured and prepared in advance. The conditions of the chromatograph are as follows.

(Measurement condition)
Device used: High-speed GPC device: Tosoh HLC-8320GPC EcoSEC system (RI detector built-in)
Guard column: Tosoh Corporation TSKguard column SuperHZ-H (4.6 mm ID × 2 cmL) × 1 Column: Tosoh Corporation TSKgel Super HZM-H (4.6 mm ID × 15 cmL) × 2 Column temperature: 40 ° C.
System temperature: 40 ° C
Mobile phase: tetrahydrofuran Mobile phase flow rate: sample side 0.175 mL / min, reference side 0.175 mL / min Detector: RI detector Sample concentration: 0.3 g / L
Injection volume: 50 μL
Measurement time: 0-25 minutes Run time: 25 minutes Sampling pitch: 200 msec

(Creation of calibration curve)
As a standard polystyrene sample for calibration curve, the weight average molecular weight of Tosoh Corp. "TSK standard POLYSTYRENE" is 5,480,000, 3,840,000, 355,000, 102,000, 37,900, 9 Standard polystyrene samples having a weight-average molecular weight of 1,030,000 of 100, 2,630, 500 and Showa Denko trade name "Shodex STANDARD" are used.

  The method of preparing the calibration curve is as follows. Group A (weight average molecular weight: 1,030,000), group B (weight average molecular weight 3,840,000, 102,000, 9,100, 500) and group C as standard polystyrene samples for the calibration curve (The weight average molecular weight is 5,480,000, 355,000, 37,900, 2,630). 5 mg of group A is weighed and then dissolved in 20 mL of tetrahydrofuran, 5 B to 10 mg of each group is weighed and then dissolved in 50 mL of tetrahydrofuran, and 1 mg to 5 mg of group C is weighed and then dissolved in 40 mL of tetrahydrofuran. Calibration curve (tertiary expression) from HLC-8320 GPC dedicated data analysis program GPC workstation (EcoSEC-WS) from the retention time obtained after injecting 50 μL of prepared A, B and C solutions and measuring standard polystyrene calibration curve It is obtained by preparing it, and it measures using the calibration curve.

<Method of measuring average primary particle diameter>
With the use of a cutter knife, the center of the particles of the expandable particles is cut out from the surface of the expanded particles and the expanded molded product as a sample for measurement. The cut-out sample is fixed to a cryosample table with an adhesive, and then ultrathin using an ultramicrotome (LEICA ULTRACUT UCT, manufactured by Leica Microsystems) and a freeze slice preparation system (LEICA EM FCS, manufactured by Leica Microsystems) Sections (90 nm thickness) are prepared. Then, using a transmission electron microscope (H-7600, manufactured by Hitachi High-Technologies Corporation), the ultra-thin section is photographed (magnification: 50,000 times). At least 200 carbon blacks are photographed per sample, the diameter of each particle is measured, and their average value is calculated. In addition, it is desirable to measure the measurement location as a primary particle that can be clearly recognized without losing the outer edge.

<Method of measuring amount of carbon black in resin>
The amount of carbon black in the resin is measured using a thermogravimetry-differential thermal measurement device TG / DTA 6200 type (manufactured by SII Nano Technology Inc.). For example, in the case of foamable particles, foam particles, foam molded articles, etc. in which a foaming agent or an organic solvent is contained in the resin, the foaming agent in the resin is allowed to stand in a thermostat at 120 ° C. for 2 hours. Let what and the organic solvent were removed be a measurement sample. The sample is packed with about 15 mg of a sample without gaps in the bottom of a platinum measuring container, and alumina is measured as a reference substance. As temperature conditions, the temperature is raised from 30 ° C. to 520 ° C. at a rate of 10 ° C./min and a nitrogen gas flow rate of 230 mL / min, and then the temperature is raised from 520 ° C. to 800 ° C. at an air flow rate of 160 mL / min. The TG curve (vertical axis: TG (%), horizontal axis: temperature (° C)) is obtained, based on which the weight loss of the sample weight at the temperature rise from 520 ° C to 800 ° C is calculated. And).
The mass ratio of carbon black to styrene resin at this time has the following relationship.
Carbon black: styrenic resin = 1: (100 / w-1)
w: Value of mass% of carbon black obtained from the measurement results Also, in the case of foam particles, foam molded articles and heat insulating materials for living space obtained from the same styrenic resin foamable particles, carbon black and styrenic resin The mass ratio has a similar value.

<Bulk density of foamed particles>
The bulk density of the foamed particles is measured in accordance with JIS K 6911: 1995 “Thermosetting plastic general test method”. Specifically, first, Wg of foam particles is collected as a measurement sample, and the measurement sample is allowed to drop naturally into a measuring cylinder. The volume V cm ³ of the measurement sample dropped into the measuring cylinder is measured using an apparent density measuring device according to JIS K6911. The bulk density of the foamed particles is calculated by substituting Wg and Vcm ³ into the following equation.
Bulk density of foamed particles (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)

<Density of Foamed Molding>
The mass (a) and the volume (b) of the test piece (example 75 × 300 × 30 mm) cut out from the foam molded product (formed and dried at 40 ° C. for 20 hours or more) each have three or more significant figures The density (g / cm ³ ) of the foam is determined by the formula (a) / (b).

<Average bubble diameter>
The average cell diameter is measured in accordance with the test method of ASTM D2842-69. The foamed particles, and any part of the foamed molded body, are cross-sectioned using a razor blade. This cut surface is enlarged by 100 times using a scanning electron microscope (JSM-6360 LV manufactured by NEC Corporation) to create an image.
Next, a 60 mm straight line is drawn at any position in the range of 20% in the radial direction of the expanded particle from the expanded particle interface on the image of the cut surface. The number of bubbles on a straight line is counted, and the average chord length (t) of the bubbles is calculated by the following equation.
Average chord length t (μm) = 60 / (number of bubbles × magnification of image)
The average bubble diameter (D) of this bubble is calculated by the following equation.
Average bubble diameter D (μm) = t / 0.616
The above operation is performed with N number 10, and the average value is taken as the average bubble diameter.

<Thermal conductivity>
From the foam molded body, a rectangular parallelepiped test piece of 200 mm long × 200 mm wide × 30 mm thickness is cut out. Next, the cut-out test piece is allowed to stand in a constant temperature bath at 60 ° C. for 72 hours to remove the foaming agent contained in the foam. Thereafter, curing is carried out at a temperature of 23 ° C. ± 1 ° C. and a humidity of 50 ± 10% for 24 hours or more to obtain a test piece for thermal conductivity measurement. The thermal conductivity (W / m · K) of the test piece for measurement is measured at a measurement temperature of 23 ° C. by a flat plate heat flow meter method in accordance with JIS A 1412-2 (1999 “foamed plastic heat insulating material”. The rate is an indicator of adiabaticity.
From the value of the obtained thermal conductivity (W / m · K), the adiabaticity is evaluated according to the following criteria.
0.0310 (W / m · K) or less: Heat insulation property is further excellent (A)
More than 0.0310 and less than or equal to 0.0320: better heat insulation (B)
More than 0.0320 and less than or equal to 0.0340: Excellent heat insulation (C)
Exceeding 0.0340 (W / m · K): Poor heat insulation (D)
In the present invention, the value of the thermal conductivity of the foamed molded article is a value after removing the foaming agent contained in the foamed molded article. In addition, when it measures without removing the foaming agent in a foaming molding, since the thermal conductivity of foaming agents, such as butane and pentane, is lower than the thermal conductivity of air, the value of the thermal conductivity of a foaming molding is And about 0.002 (W / m · K).

<Specific surface area>
The specific surface area (m ² / g) of carbon black is measured according to ASTM D-6556.

<The longest diameter of the expandable particles, the expanded particles and the aggregate of carbon black in the expanded molded product>
Using the cutter knife, the foamable particles are cut at the center of the particles, the foam particles, and the skin portion of the foam molded product as a sample for measurement. The cut-out sample is fixed to a cryosample table with an adhesive, and then ultrathin using an ultramicrotome (LEICA ULTRACUT UCT, manufactured by Leica Microsystems) and a freeze slice preparation system (LEICA EM FCS, manufactured by Leica Microsystems) Sections (90 nm thickness) are prepared. Then, using a transmission electron microscope (H-7600, manufactured by Hitachi High-Technologies Corporation), the ultra-thin section is photographed (magnification multiple: 10,000). At least 200 independent discrete clumps are taken per sample. In the photographed image, the longest diameter of the distance between any two points on the outer edge of the aggregate, in which the primary particles of carbon black appear to overlap, was taken as the longest diameter of the aggregate, and their average value was calculated. The longest diameter connecting the above two points is set so as to always overlap the primary particle on the photograph. That is, it is assumed that the longest diameter does not pass through the background of the photograph.

<Blackness of Foamed Molding>
The degree of blackness ΔE ′ of the foam molded article is evaluated by color difference measurement based on JIS Z8729-2004 “Color display method-L ^* a ^* b ^* color system”.
For measurement, a color difference meter (manufactured by Konica Minolta, model: CR-400) and a standard white board calibration plate (Y: 94.3, x: 0.3144, y: 0.3208) are used for the standard combination.
Specifically, the lightness L ^* value and the color coordinates a ^* value and b ^* value obtained by measuring the measurement area as φ 8 mm and measuring the average value for arbitrary 10 points of the vertical and horizontal surfaces of the foam molded body is black according to the following equation Calculate ΔE 'as a degree.
ΔE '= L ^* + | a ^* | + | b ^* |
The degree of blackness is evaluated according to the following criteria from the obtained ΔE ′.
31 ≦ ΔE ′ ≦ 50: good (○)
ΔE ′ <31 and 50 <ΔE ′: Bad (x)

<Method of measuring absorbance>
A sample of 1.0 mm ± 0.1 mm in thickness is obtained from any part of the resulting foam molded article. The absorbance of the sample in the transmitted infrared is then measured by the following method.
・ Fourier transform infrared spectrometer NICOLET iS5 (manufactured by Thermo Fisher Scientific Co., Ltd.)
・ Measurement method: Transmission method ・ Measurement wave number domain: 4000 cm ^{-1 to} 400 cm ^-1
・ Wavenumber dependence of measurement depth: not corrected ・ Detector: DTGSKBr
・ Resolution: 4 cm ^-1
・ Number of integrations: 16 times (same for background measurement)

<Method of measuring water absorption>
The water absorption amount of the foam molded article was measured in accordance with JIS A 9511: 2006 R Foamed Plastic Heat Insulating Material Measurement Method B. 3 pieces of 100 x 100 x 25 mm whole surface cut surface is immersed in fresh water for 10 seconds, then immersed in ethanol for 10 seconds, and left to stand at normal temperature (23 ° C) for 60 minutes as reference mass (m0) I assume. Next, it is again immersed in fresh water and allowed to absorb water for 24 hours, and then the mass (m1) is measured by the same method as the reference mass measurement.
For each of the three test pieces, W is calculated by the following formula, and the average value is taken as the water absorption (g / 100 cm ² ).
W = (m1-m0) / A × 100
m1 (g): After 24 hours water absorption Mass m0 (g): Reference mass A (cm ² ): Total surface area

<Method of measuring flame resistance and evaluation>
From the obtained foam molded article, five rectangular test pieces each having a size of 200 mm × 25 mm × 10 mm in height are cut out with a vertical cutter. After curing the cut products in an oven at 60 ° C. for 1 day, the individual anti-inflammatory times are measured according to the measuring method A of JIS A 9511-2006. The average value of the individual quenching times of the five test pieces is taken as the quenching time. In addition, the flame resistance was evaluated on the basis of the following references | standards from the extinction time.
Good (○) ··············································································· Measured Absent

<Total content of aromatic organic compounds>
The total content of the aromatic organic compound is a value measured by the following << Method of measuring volatile organic compound (VOC) content >>.
<< Method of measuring volatile organic compound (VOC) content >>
After precisely weighing 1 g of the foam molded body and adding 1 mL of a dimethylformamide solution containing 0.1% by volume of cyclopentanol as an internal standard solution, dimethylformamide is further added to the dimethylformamide solution to prepare 25 mL of a measurement solution. 1.8 μL of this measurement solution is supplied to a sample vaporization chamber at 230 ° C., and a chart of each volatile organic compound detected by a gas chromatograph (manufactured by Shimadzu Corporation, trade name “GC-14A”) is supplied under the following measurement conditions Then, the amount of volatile organic compound is calculated from each chart based on the calibration curve of each volatile organic compound, which is measured in advance, and the amount of volatile organic compound in the foam molded body is calculated. When the amount of volatile organic compound in the foamable particles is calculated, 1 g of the foamable particles is precisely weighed and measured in the same manner.
Detector: FID
Column: Made by GL Science (3 mmφ × 2.5 m)
Liquid phase; PEG-20M PT 25%
Carrier; Chromosorb W AW-DMCS
Mesh: 60/80
Column temperature: 100 ° C
Detector temperature: 230 ° C
DET temperature: 230 ° C
Carrier gas (nitrogen)
Carrier gas flow rate (40 mL / min)
The total amount of volatile organic compounds corresponding to the aromatic organic compound among the volatile organic compound (VOC) content described above is taken as “the total content of aromatic organic compounds”.

Example 1
7995 g of a polystyrene resin having a weight average molecular weight of 300,000 and 2000 g of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd .: Denka black granular grade, average primary particle diameter 35 nm, specific surface area 69 m ² / g), ethylenebisstearic acid amide (Kao Corporation Product: Kao wax EB-FF) 5 g is supplied to a twin-screw extruder, melt-kneaded at 250 ° C., extruded from the extruder into strands, this strand is cut for each predetermined length, and cylindrical polystyrene Base resin seed particles (diameter: 0.8 mm, length: 0.8 mm) were produced.
Next, 2000 g of water, 300 g of columnar polystyrene resin seed particles, 6 g of magnesium pyrophosphate and 0.3 g of sodium dodecylbenzenesulfonate are supplied to a polymerization vessel equipped with a stirrer, and the mixture is heated to 72 ° C. while stirring and dispersion Was produced.

Subsequently, 9.0 g of a polymerization initiator t-butylperoxy-2-ethylhexanoate and 1.8 g of a polymerization initiator t-butylperoxy-2-ethylhexyl monocarbonate are dissolved in 100 g of styrene, and all the styrene is dissolved. The dispersion was supplied with stirring.
Then, the dispersion was heated from 72 ° C. to 90 ° C. 60 minutes after the styrene was completely fed into the dispersion. After raising the temperature, polystyrene resin seed particles were grown by seed polymerization while supplying 800 g of styrene at a constant rate over 150 minutes. After all the styrene was supplied, the mixture was stirred at a constant temperature of 90 ° C. for 1 hour, and then heated to 125 ° C. and stirred for 2 hours. After stirring, the mixture was cooled to obtain 1200 g of polystyrene resin particles.

Next, 1200 g of the obtained polystyrene resin particles, 2000 g of water, 6 g of magnesium pyrophosphate and 0.3 g of sodium dodecylbenzene sulfonate are supplied to a polymerization vessel equipped with a stirrer, and the mixture is heated to 70 ° C. while stirring and dispersed Was produced.
Next, 10.8 g of tetrabromocyclooctane as a flame retardant and 3.6 g of dicumyl peroxide as a flame retardant auxiliary were supplied into the dispersion, and the polymerization vessel was sealed and heated to 90 ° C.
Subsequently, butane was impregnated into the polystyrene resin particles by pressing 108 g of butane into the polymerization vessel and holding it for 6 hours. After impregnation, the inside of the polymerization vessel was cooled to 25 ° C. to obtain styrenic resin foamable particles. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The weight average molecular weight of the obtained styrenic resin foamable particles was 79,000. The styrenic resin foamable particles obtained were spherical.

After applying polyethylene glycol as an antistatic agent on the surface of styrenic resin foamable particles, zinc stearate and hydroxystearic acid triglyceride were applied on the surface of styrenic resin foamable particles. In addition, each of zinc stearate and hydroxystearic acid triglyceride was adjusted to 0.05% by mass in the styrene resin foamable particles.
Thereafter, the styrene resin foamable particles were left to stand in a thermostatic chamber at 13 ° C. for 5 days. The butane content in the styrenic resin foamable particles after standing was measured using a gas chromatograph and was 5.8 mass%.

Then, the styrenic resin foamable particles were heated to be prefoamed to a bulk density of 0.019 g / cm ³ to obtain prefoamed particles. The pre-expanded particles were aged at 20 ° C. for 24 hours.
Next, the pre-foamed particles were filled in a mold and heat-foamed to obtain a foam molded product of 400 mm long × 300 mm wide × 30 mm thickness. The foam-molded article was dried in a drying room at 50 ° C. for 6 hours, and the density of the foam-molded article was measured to be 0.020 g / cm ³ . This foamed molded product was excellent in appearance without shrinkage. Further, the average cell diameter of the foam molded article was 102 μm.

(Example 2)
The polymerization initiator t-butylperoxy-2-ethylhexanoate was changed from 9.0 g to 5.4 g, and the bulk density of the pre-foamed particles was changed from 0.019 g / cm ³ to 0.016 g / cm ³ Styrene resin foamable particles, pre-foamed particles, and a foam were obtained in the same manner as in Example 1 except that the density of the foam was changed from 0.020 g / cm ³ to 0.017 g / cm ³ . . The weight average molecular weight of the styrenic resin foamable particles obtained in this process was 750,000 and was spherical. Further, the average cell diameter of the obtained foam molded article was 590 μm.
(Example 3)
After the bulk density obtained in Example 1 was aged for 24 hours at 20 ° C. The pre-expanded particles of 0.019 g / cm ^3, to obtain a pre-expanded particles having a bulk density of 0.0135 g / cm ³ by heating again . The pre-expanded particles were aged at 20 ° C. for 24 hours. Next, molding was performed in the same manner as in Example 1 to obtain a foam molded article having a density of 0.0143 g / cm ³ . The average cell diameter of this foam was 130 μm.

(Example 4)
Nippon Carbon Co., Ltd., carbon black-containing polystyrene resin masterbatch (product name: EX 4050 B) (average primary particle diameter 55 nm, specific surface area 28 m ² / g, sulfur content 4000 ppm, ash content 0.03% carbon black containing 20% by mass) ) Is fed to a twin-screw extruder and melt-kneaded at 250 ° C., extruded from the extruder in the form of strands, and cut into strands of a predetermined length to obtain columnar polystyrene-based resin seed particles (diameter) Styrenic resin foamable particles, pre-foamed particles, and a foam-molded article were obtained in the same manner as in Example 1 except that the length was changed to 0.8 mm and the length: 0.8 mm.

(Example 5)
Acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd .: Denka black granular grade, average primary) used in Example 1 with respect to 95 parts by mass of virgin polystyrene (manufactured by Toyo Styrene Co., Ltd., trade name "HRM-10N") having a weight average molecular weight of 200,000. 5 parts by mass of particle diameter 35 nm, specific surface area 69 m ² / g), 0.5 parts by mass of fine powder talc as inorganic foaming nucleating agent, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) as flame retardant Ether (5 parts by mass) were continuously fed at 150 kg per hour to a 90 mm bore single-screw extruder. The temperature in the extruder was set to a maximum temperature of 220 ° C., and after melting the resin, 6 parts by mass of isopentane was injected as a foaming agent from the middle of the extruder with respect to 100 parts by mass of the resin. The resin and the foaming agent are kneaded and cooled in the extruder, and the resin temperature at the tip of the extruder is maintained at 170 ° C., the pressure of the resin introduction portion of the die is maintained at 15 MPa, and the land length is 3 mm. At the same time as the foaming agent-containing molten resin is extruded from the die in which 200 small holes of 0 mm are arranged, into the cutting chamber connected to the discharge side of this die and the water of 30 ° C. circulates, The extrudate was cut with a high speed rotary cutter with a blade. The cut particles were transported to a particle separator while being cooled with circulating water, and the particles were separated from the circulating water. Furthermore, the collected particles were dehydrated and dried to obtain styrenic resin foamable particles. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The obtained styrenic resin foamable particles were almost spherical without occurrence of deformation, whiskers and the like, and the average particle diameter was about 1.1 mm.
Based on 100 parts by mass of the styrenic resin foamable particles obtained, 0.03 parts by mass of polyethylene glycol, 0.15 parts by mass of zinc stearate, 0.05 parts by mass of monoglyceride stearate, 0.05 parts by mass of hydroxystearate triglyceride Parts were uniformly coated on the entire surface of the styrenic resin foamable particles.
By heating the styrenic resin foamable particles produced as described above, prefoaming was performed to a bulk density of 0.019 g / cm ³ to obtain prefoamed particles. The pre-expanded particles were aged at 20 ° C. for 24 hours.
Next, the pre-foamed particles were filled in a mold and heat-foamed to obtain a foam molded product of 400 mm long × 300 mm wide × 30 mm thickness. The foam-molded article was dried in a drying room at 50 ° C. for 6 hours, and the density of the foam-molded article was measured to be 0.020 g / cm ³ . This foamed molded product was excellent in appearance without shrinkage.

(Example 6)
The carbon black-containing polystyrene resin masterbatch used in Example 4 with respect to 75 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000 (trade name "HRM-10N" manufactured by Toyo Styrene Co., Ltd.) 25 parts by mass of EX 4050 B) (average primary particle diameter 55 nm, specific surface area 28 m ² / g, sulfur content 4000 ppm, ash content 0.03% carbon black containing 20% by mass), fine powder talc 0.5 as inorganic foaming nucleating agent Styrenic resin foamable particles, pre-foamed particles in the same manner as in Example 5 except that the mass part is changed to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant , A foam molded body was obtained. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Example 7)
To prepare pre-expanded particles having a bulk density of 0.013 g / cm ^3, density of 0.014 g / except that to obtain a foamed molded article of cm ³ in the same manner as in Example 6 styrene resin expandable particles, pre-expanded particles , A foam molded body was obtained.
(Example 8)
Styrenic resin foamable particles and pre-foamed particles are prepared in the same manner as in Example 6 except that pre-foamed particles having a bulk density of 0.024 g / cm ³ are prepared and a foam molded article having a density of 0.025 g / cm ³ is obtained. , A foam molded body was obtained.

(Example 9)
The feed material to the extruder was 87.5 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000, 12.5 parts by mass of a carbon black-containing polystyrene resin masterbatch (EX 4050B), and finely powdered talc 0. Styrenic resin foamable particles, pre-foaming in the same manner as in Example 6 except that 5 parts by mass and 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant are changed Particles were obtained as a foam. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 39 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Example 10)
The feed material to the extruder is 35 parts by mass of carbon black-containing polystyrene resin masterbatch (EX 4050 B), and 0.5 parts by mass of fine powder talc as an inorganic foaming nucleating agent, based on 65 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000. Styrenic resin foamable particles, pre-foamed particles, foam molding in the same manner as in Example 6 except that it is changed to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant I got a body. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 13.3 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Example 11)
50 parts by mass of carbon black-containing polystyrene resin masterbatch (EX 4050 B), 0.5 parts by mass of fine powder talc as an inorganic foaming nucleating agent, with respect to 50 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000 Styrenic resin foamable particles, pre-foamed particles, foam molding in the same manner as in Example 6 except that it is changed to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant I got a body. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 9 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Example 12)
Polystyrene resin masterbatch (product name: EX 4050A, average primary particle diameter 40 nm, specific surface area 254 m ² / g) manufactured by Nippon Pigment Co., Ltd. relative to 75 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000 25 parts by mass of carbon black (containing 20%), 0.5 parts by mass of fine powder talc as an inorganic foaming nucleating agent, 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant Styrene-based resin foamable particles, pre-foamed particles, and a foam-molded product were obtained in the same manner as in Example 6 except for changing. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Example 13)
5 parts by mass of conductive carbon black (average primary particle diameter 35 nm, specific surface area 80 m ² / g) with respect to 95 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000, and fine powder as an inorganic foaming nucleating agent Styrenic resin foamable particles in the same manner as in Example 5 except that 0.5 parts by mass of talc and 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant are changed , Pre-foamed particles, and a foamed molded product. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

(Comparative example 1)
Styrenic resin foamable particles and pre-foamed particles in the same manner as in Example 1 except that acetylene black is changed to furnace black (Mitsubishi Chemical Corporation # 5, average primary particle diameter 76 nm, specific surface area 29 m ² / g) , A foam molded body was obtained. The weight average molecular weight of the styrenic resin foamable particles obtained in this process was 770,000 and was spherical. Moreover, the average cell diameter of the obtained molded object was 200 micrometers.
(Comparative example 2)
Styrenic resin foamable particles and pre-foamed particles in the same manner as in Example 5 except that acetylene black is changed to furnace black (manufactured by Mitsubishi Chemical Corporation: # 33, average primary particle diameter 30 nm, specific surface area 85 m ² / g) , A foam molded body was obtained.
(Comparative example 3)
Styrenic resin foamable particles and pre-foamed particles in the same manner as in Example 5 except that acetylene black is changed to furnace black (manufactured by Mitsubishi Chemical Corporation: # 970, average primary particle diameter 16 nm, specific surface area 260 m ² / g) , A foam molded body was obtained.

(Example 14)
The conductive carbon black (Imeris Graphite & Carbon Co., Ltd .: ENSACO 250G, average) per 95 parts by mass of virgin polystyrene (manufactured by Toyo Styrene Co., Ltd., trade name "HRM-10N") having a weight average molecular weight of 200,000. 5 parts by mass of a primary particle diameter 45 nm, specific surface area 65 m ² / g, 0.5 parts by mass of fine powder talc as an inorganic foaming nucleating agent, tetrabromobisphenol A-bis (2,3-dibromo-2-) as a flame retardant Styrenic resin foamable particles, pre-foamed particles, and a foam molded article were obtained in the same manner as in Example 5 except that the amount of methyl propyl ether was changed to 5 parts by mass. The obtained styrenic resin foamable particles were carbon black: styrenic resin = 1: 19 (mass ratio). The obtained foam molded article was excellent in appearance without shrinkage.

  Various physical properties of the foamable particles, the foam particles and the foam molded body and the thermal conductivity of the foam molded body are described in Tables 2 and 3 together with the volume resistivity of the carbon black. In Tables 2 and 3, the volume resistivity measured using a polyethylene resin is referred to as “volume resistivity (PE)”, and the volume resistivity measured using a polystyrene resin is referred to as “volume resistivity (PS)”. . In addition, the cross section of the foam molded article produced in Example 1 and the foam particles of Example 2 was observed with an electron microscope. The images are shown in FIGS.

It can be seen from Table 3 that the inclusion of conductive carbon black having a volume resistivity (PE and / or PS) of not more than 1.0 × 10 ⁴ Ω · cm makes it possible to obtain a foam molded article having good heat insulation .

(Example 15)
Acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd .: Denka black granular grade, average primary particle diameter 35 nm, specific surface area 69 m ² ) based on 95 parts by weight of polystyrene (manufactured by Toyo Styrene Co., Ltd., trade name "HRM-10N") having a weight average molecular weight of 200,000. 5 parts by weight / g), 0.5 parts by weight of finely divided talc as inorganic foaming nucleating agent, 5 parts by weight of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as flame retardant, The mixture was continuously fed at 150 kg per hour to a 90 mm bore single screw extruder. The temperature in the extruder was set to a maximum temperature of 220 ° C., and after melting the resin, 6 parts by mass of isopentane was injected as a foaming agent from the middle of the extruder with respect to 100 parts by mass of the resin.

  The resin and the foaming agent are kneaded and cooled in the extruder, and the resin temperature at the tip of the extruder is maintained at 170 ° C., the pressure of the resin introduction portion of the die is maintained at 15 MPa, and the land length is 3 mm. At the same time as the foaming agent-containing molten resin is extruded from the die in which 200 small holes of 0 mm are arranged, into the cutting chamber connected to the discharge side of this die and the water of 30 ° C. circulates, The extrudate was cut with a high speed rotary cutter with a blade. The cut particles were transported to a particle separator while being cooled with circulating water, and the particles were separated from the circulating water. Furthermore, the collected particles were dehydrated and dried to obtain expandable styrenic resin particles.

The obtained expandable styrene-based resin particles were carbon-based infrared shielding agent: styrene-based resin = 1: 19 (mass ratio). The obtained expandable styrenic resin particles were substantially spherical without occurrence of deformation, whiskers and the like, and had an average particle diameter of about 1.1 mm. Based on 100 parts by mass of the expandable styrenic resin particles obtained, 0.03 parts by mass of polyethylene glycol, 0.15 parts by mass of zinc stearate, 0.05 parts by mass of monoglyceride stearate, 0.05 parts by mass of hydroxystearate triglyceride Parts were uniformly coated on the entire surface of the expandable styrenic resin particles. By heating the foamable styrenic resin particles produced as described above, prefoaming was performed to a bulk density of 0.020 g / cm ³ to obtain prefoamed particles. The pre-expanded particles were aged at 20 ° C. for 24 hours. Next, the pre-foamed particles were filled in a mold and heat-foamed to obtain a foam molded product of 400 mm long × 300 mm wide × 30 mm thickness.

The foam-molded article was dried in a drying room at 50 ° C. for 6 hours, and the density of the foam-molded article was measured to be 0.020 g / cm ³ . This foamed molded product was excellent in appearance without shrinkage. The obtained foam molded body was sliced to a thickness of 1.0 ± 0.1 mm using a ham slicer, and used as a sample for absorbance measurement. The absorbance obtained by transmission infrared absorption analysis of this foam molded article sample was calculated. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.98, the absorbance B at a wave number of 500 cm ⁻¹ was 0.78, and the ratio of absorbance (A / B) was 1.26. Moreover, the heat conductivity of this foam-molded body was excellent with 0.031 W / mk. Further, the water absorption was as low as 0.08 g / 100 cm ² . The average value of the longest diameter of the aggregate was 270 nm.

(Example 16)
Polystyrene resin masterbatch (product name: EX 4050 B, average primary particle diameter 55 nm, ratio) manufactured by Nippon Pigment Co., Ltd. relative to 75 parts by mass of polystyrene (manufactured by Toyo Styrene Co., Ltd., trade name "HRM-10N") having a weight average molecular weight of 200,000 A foamed molded article was obtained in the same manner as in Example 14 except that 25 parts by mass of a carbon black having a surface area of 28 m ² / g was used. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.97, the absorbance B at a wave number of 500 cm ⁻¹ was 0.85, and the ratio of absorbance (A / B) was 1.14. The thermal conductivity of the foam molded article was 0.032 W / mk, and the water absorption amount was 0.09 g / 100 cm ² . The average value of the longest diameter of the aggregate was 340 nm.
(Example 17)
Polystyrene resin masterbatch (product name: EX 4050A, average primary particle diameter 15 nm, ratio) manufactured by Nippon Pigment Co., Ltd. relative to 75 parts by mass of polystyrene (manufactured by Toyo Styrene Co., Ltd., trade name "HRM-10N") having a weight average molecular weight of 200,000 A foamed molded article was obtained in the same manner as in Example 14 except that 25 parts by mass of a carbon black having a surface area of 254 m ² / g was used. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.98, the absorbance B at a wave number of 500 cm ⁻¹ was 0.86, and the ratio of absorbance (A / B) was 1.14. The thermal conductivity of the foamed molded article was 0.032 W / mk, and the amount of water absorption was 0.11 g / 100 cm ² . The average value of the longest diameter of the aggregate was 278 nm.
(Example 18)
A foamed molded article was obtained in the same manner as in Example 14 except that an average primary particle diameter of 40 nm, a specific surface area of 800 m ² / g, and ketjen black (manufactured by Lion Corporation: EC300J) were used. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.98, the absorbance B at a wave number of 500 cm ⁻¹ was 0.85, and the ratio of absorbance (A / B) was 1.15. The thermal conductivity of the foam molded article was 0.030 W / mk, and the water absorption amount was 0.1 g / 100 cm ² . The average value of the longest diameter of the aggregate was 255 nm.

(Example 19)
A foamed molded article was obtained in the same manner as in Example 14 except that ketjen black (manufactured by Lion Corporation: EC600JD) having an average primary particle diameter of 34 nm and a specific surface area of 1400 m ² / g was used. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.98, the absorbance B at a wave number of 500 cm ⁻¹ was 1.2, and the ratio of absorbance (A / B) was 0.82. The thermal conductivity of the foam molded article was 0.030 W / mk, and the water absorption amount was 0.15 g / 100 cm ² . The average value of the longest diameter of the aggregate was 289 nm.

(Comparative example 4)
A foamed molded article was obtained in the same manner as in Example 12 except that acetylene black was not added. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.94, the absorbance B at a wave number of 500 cm ⁻¹ was 0.37, and the ratio of absorbance (A / B) was 2.54. The water absorption of the foam was 0.20 g / 100 cm ² . The thermal conductivity of the foam molded article was 0.038 W / mk, which was insufficient.
(Comparative example 5)
A foamed molded article was obtained in the same manner as in Example 12 except that furnace black (manufactured by Mitsubishi Chemical Corporation: # 970) having an average primary particle diameter of 16 nm and a specific surface area of 260 m ² / g was used instead of acetylene black. The absorbance A at a wave number of 1000 cm ⁻¹ was 0.88, the absorbance B at a wave number of 500 cm ⁻¹ was 0.40, and the ratio of absorbance (A / B) was 2.20. The water absorption of the foam was 0.22 g / 100 cm ² . The thermal conductivity of the foam molded article was 0.037 W / mk, which was insufficient.

  From Table 4 above, it was shown that a foam molded article having an absorbance ratio A / B of 0.8 to 2.0 has good thermal conductivity.

Claims (20)

Containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less, a styrenic resin, and a foaming agent,
The primary particles of the conductive carbon black are contained as a plurality of aggregated particles in the styrene resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The clumps are
(I) Average value of the longest diameter of 180 to 500 nm,
(Ii) styrenic resin foamable particles having a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0.   The styrenic resin foamable particles according to claim 1, wherein the conductive carbon black is acetylene black, ketjen black or a mixture thereof. The styrenic resin foamable particles according to claim 1, wherein the conductive carbon black has a specific surface area of 10 to 3000 m ² / g. Containing conductive carbon black with a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin,
The primary particles of the conductive carbon black are contained as a plurality of aggregated particles in the styrene resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The clumps are
(I) Average value of the longest diameter of 180 to 500 nm,
(Ii) Styrene resin foam particles having a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0.   The styrene resin foam particles according to claim 4, wherein the conductive carbon black is acetylene black, ketjen black or a mixture thereof.   The styrene resin foam particles according to claim 4 or 5, wherein the styrene resin foam particles have an average cell diameter of 150 to 350 μm. The conductive carbon black, expanded styrene resin beads according to any one of claims 4-6 having a specific surface area of 10~3000m ² / g. A conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrenic resin, which is composed of a plurality of foam particles fused together,
The primary particles of the conductive carbon black are contained as a plurality of aggregated particles in the styrene resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The clumps are
(I) Average value of the longest diameter of 180 to 500 nm,
(Ii) A styrenic resin foam molded article having a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0.   The styrene resin foam molded article according to claim 8, wherein the conductive carbon black is acetylene black, ketjen black or a mixture thereof.   The styrene resin foam molding according to claim 8 or 9, wherein the styrene resin foam particles have an average cell diameter of 150 to 350 μm. In the measurement of the color difference of the surface of the foamed molded article based on JIS Z8729-2004 “Color display method-L * a * b * color system”, the following formula:
31 ≦ ΔE ′ = L ^* + | a ^* | + | b ^* | ≦ 50
(Wherein, ΔE ′ represents the degree of blackness, L ^* the lightness, a ^* and b ^* the color coordinates)
The styrenic resin foam-molded article according to any one of claims 8 to 10, which satisfies the relation shown by the above. The styrene resin foam molded article is
Containing 0.5 to 20 parts by mass of conductive carbon black with respect to 100 parts by mass of styrene resin,
The absorbance A at a wave number of 1000 cm ^-1 and the absorbance B at a wave number of 500 cm ^-1 obtained by transmission method infrared analysis show a ratio A / B of 0.8 to 2.0. The styrenic resin foam-molded body as described in-.   The styrene resin foam molded article according to claim 12, wherein the absorbance B is 0.5 or more. Styrene type resin foamed molded product according to the styrenic resin foam molded article, any one of claims 8 to 13 having a density of 0.01-0.04 / cm ^3. The styrene resin foam molded article according to any one of claims 8 to 14, wherein the conductive carbon black has a specific surface area of 10 to 3000 m ² / g. Styrene type resin foamed molded product according to the styrenic resin foam molded article, any one of claims 8 to 15 having a water absorption of less than 0.5 g / 100 cm ^2.   The styrenic resin foam-molded article according to any one of claims 8 to 16, further comprising a flame retardant.   An aromatic organic compound comprising the styrenic resin foam-molded article according to claim 8, wherein the styrenic monomer in the styrenic resin foam-molded article, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, benzene Thermal insulation for living space, wherein the total content of compounds is less than 2000 ppm. It is a method of producing styrenic resin foamable particles according to claim 1,
A styrene monomer is impregnated into the seed particles in a dispersion obtained by dispersing, in water, seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin. And a process of
Simultaneously with or after the impregnation, a step of polymerizing the styrenic monomer;
A process for producing styrenic resin foamable particles, comprising the step of impregnating a blowing agent simultaneously with or after the polymerization. It is a method of producing styrenic resin foamable particles according to claim 1,
Melt-kneading a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin,
Injecting a foaming agent into the molten resin obtained in the melt-kneading step;
A step of extruding the molten resin obtained in the blowing agent injection step into a liquid, cutting it, and then solidifying it;