JP6473675B2 - Styrenic resin foamable particles and method for producing the same, foamed particles, foamed molded article and use thereof - Google Patents

Description

  The present invention relates to styrenic resin foamable particles, a method for producing the same, foamed particles, a foamed molded article, and uses thereof. More specifically, the present invention relates to a styrenic resin foam molded article having excellent heat insulation and its use, styrene resin foamable particles and foamed particles for producing the molded article, and production of styrene resin foamable particles. Regarding the method.

  Conventionally, foamed molded products are lightweight and excellent in heat insulation and mechanical strength. Therefore, heat insulating materials used in houses and automobiles, heat insulating materials used in building materials, packing materials for transportation such as fish boxes and food containers, and cushioning materials. Etc. are used. Among them, in-mold foam molded articles produced using foamable particles as raw materials are often used because of the advantage that a desired shape is easily obtained.

As the foam molded article, a styrene resin foam molded article derived from styrene resin foamable particles is widely used. The styrenic resin foam molded body heats and expands styrene resin foamable particles to obtain prefoamed particles, and then heats the prefoamed particles obtained while secondary foaming in the mold cavity. It is obtained by integrating by fusing.
Styrenic resin foam moldings have various properties, for example, excellent thermal insulation properties. Excellent heat insulation is required for various applications from the viewpoint of energy saving. Specific applications include wall insulation, floor insulation, roof insulation, automotive insulation, hot water tank insulation, piping insulation, solar system insulation, water heater insulation, food Containers for industrial products, packing materials for fish and agricultural products, embankment materials, tatami core materials, and the like.

  It is desired that the heat insulating property required for the foam molded body is further improved from the viewpoint of energy saving. As a method for improving the heat insulation, various methods such as higher magnification, change of resin composition, use of additives, and the like are known. For example, Japanese Patent Application Laid-Open No. 63-183941 (Patent Document 1) proposes a foamed molded article containing fine powder having an infrared reflectance of 40% or more as an additive. In the example of Patent Document 1, a foam molded article using aluminum powder, silver powder, and graphite powder having a reflectance of 40% or more is carbon black (for example, generally used as a blackening agent in the foam molded article (for example, JP, 2013-6966, A: patent documents 2) It is explained that it is excellent in heat insulation than a foaming fabrication object containing an additive which has reflectance of less than 40%.

Japanese Unexamined Patent Publication No. 63-183941 JP 2013-6966 A

  With the technique described in the above publication, it is difficult to obtain a foamed molded article having sufficient heat insulating properties that has been required in recent years, and provision of a foamed molded article having higher heat insulating properties is desired.

The inventors of the present invention have studied additives that can be added to a foamed molded product in order to improve the heat insulating properties of the foamed molded product. As a result, the knowledge which specific kind of carbon black contributes to the improvement of heat insulation was acquired. This specific type of carbon black is an additive that can be covered by the concept of conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less. Here, in consideration of the fact that in Patent Document 1, carbon black is considered to be inferior in the effect of improving heat insulation, the inventors have surprisingly found that the conductivity of carbon black is related to heat insulation. This is the point of view.

Thus, according to the present invention, a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less, a styrene resin, and a foaming agent, wherein the primary particles of the conductive carbon black are the styrene. A plurality of agglomerates aggregated in a resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the aggregates are (i) an average value of the longest diameter of 180 to 500 nm; wherein for said average primary particle size of ii) 4.0 to 10.0 possess a ratio of the longest diameter of average value, the content of the conductive carbon black, 2 with respect to 100 parts by weight styrene resin Styrenic resin expandable particles that are 25 parts by weight are provided.
Further, according to the present invention, the conductive carbon black containing a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrenic resin, wherein the primary particles of the conductive carbon black are contained in the styrenic resin. Contained as agglomerated agglomerates, the primary particles have an average primary particle diameter of 18-125 nm, the agglomerates (i) an average value of the longest diameter of 180-500 nm,
(Ii) the relative said average primary particle size of 4.0 to 10.0 possess a ratio of the longest diameter of average value, the content of the conductive carbon black, 2 with respect to 100 parts by weight of a styrene resin Styrenic resin expanded particles that are ˜25 parts by mass are provided.
Furthermore, according to the present invention, the conductive carbon black is composed of a plurality of foamed particles fused to each other and containing a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin. Primary particles are contained as agglomerates aggregated in the styrenic resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the agglomerates (i) have a maximum diameter of 180 to 500 nm. the average value of the major axis, is said to the average primary particle size possess a ratio of the longest diameter of average value, the content of the conductive carbon black (ii) 4.0 to 10.0, a styrene resin 100 A styrenic resin foam molded body having 2 to 25 parts by mass with respect to parts by mass is provided.
Further, according to the present invention, the styrene resin foam molded article is composed of the styrene resin foam molded article, and includes the styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, and benzene in the styrene resin foam molded article. A heat insulating material for living space in which the total content of aromatic organic compounds is less than 2000 ppm is provided.
Furthermore, according to the present invention, there is provided a method for producing the above styrene resin foamable particles, wherein seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin are submerged in water. In the dispersion liquid dispersed in the above, the step of impregnating the seed particles with the styrenic monomer, the step of polymerizing the styrenic monomer simultaneously with or after impregnation, and the polymerization or after polymerization And a step of impregnating with a foaming agent.
Furthermore, according to the present invention, there is provided a process for producing the above-mentioned styrene resin expandable particles, the step of melt-kneading a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin. A styrenic resin comprising: a step of injecting a foaming agent into the molten resin obtained in the melt-kneading step; and a step of extruding the molten resin obtained in the foaming agent injection step into a liquid, cutting it, and then solidifying it. A method for producing expandable particles is provided.

  According to the present invention, a styrenic resin foam molded article and a heat insulating material for living space excellent in heat insulation, styrene resin foamable particles and foamed particles for producing the above foamed molded article, and styrene resin foamable particles Can be provided.

In any of the following cases, it is possible to provide styrene resin foamable particles for producing a styrene resin foamable molded article having better heat insulation.
(1) Conductive carbon black primary particles are contained as agglomerated aggregates in a styrene resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the agglomerates are (i) 180 An average value of the longest diameter of ˜500 nm and (ii) a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 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.

Moreover, in any of the following cases, styrene resin foamed particles for producing a styrene resin foamable molded article having more excellent heat insulation can be provided.
(1) Conductive carbon black primary particles are contained as agglomerated aggregates in a styrene resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the agglomerates are (i) 180 An average value of the longest diameter of ˜500 nm and (ii) a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0;
(2) the conductive carbon black is acetylene black, ketjen black or a mixture thereof;
(3) The styrene resin expanded 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 having better heat insulation.
(1) Conductive carbon black primary particles are contained as agglomerated aggregates in a styrene resin, the primary particles have an average primary particle diameter of 18 to 125 nm, and the agglomerates are (i) 180 An average value of the longest diameter of ˜500 nm and (ii) a ratio of the average value of the longest diameter to the average primary particle diameter of 4.0 to 10.0;
(2) the conductive carbon black is acetylene black, ketjen black or a mixture thereof;
(3) The styrene resin expanded particles have an average cell diameter of 150 to 350 μm;
(4) In the measurement of the color difference of the surface based on JIS Z8729-2004 “Color display method—L ^* a ^* b ^* color system”, the styrene-based resin foamed molded product has the following formula: 31 ≦ ΔE ′ = L ^* + | A ^* | + | b ^* | ≦ 50 (where ΔE ′ represents blackness, L ^* represents lightness, and a ^* and b ^* represent color coordinates);
(5) Absorbance at a wave number of 1000 cm ⁻¹ obtained by transmission infrared analysis when the styrene resin foamed 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. A ratio A / B of 0.8 to 2.0 is shown at A and absorbance B at a wave number of 500 cm ⁻¹ ;
(6) Absorbance B is 0.5 or more;
(7) The styrene resin foam molded article 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 molded article has a water absorption of less than 0.5 g / 100 cm ² ;
(10) The styrene resin foam molded article further contains a flame retardant.

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

(Styrenic resin foamable particles)
Styrenic resin foamable particles (hereinafter, foamable particles) include 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 preferred volume resistivity is 7.0 × 10 ³ Ω · cm or less, the more preferred volume resistivity is 4.0 × 10 ³ Ω · cm or less, and the more preferred 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. A lower limit value of the volume resistivity is not particularly provided, but is, for example, about 1.0 × 10 ⁻¹ Ω · cm or more. Specific values of volume resistivity are 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.

  Here, the volume resistivity is the raw material carbon black, or when the raw material carbon black is added to the master batch, expandable particles, expanded particles, and expanded molded article, the master batch, expandable particles, The carbon black taken out by removing the styrene resin in the foamed particles and the foamed molded article with an organic solvent is melt-kneaded with a polyethylene resin or a polystyrene resin (carbon black: polyethylene resin or polystyrene resin = 1). : 4 (mass ratio)), and means a value obtained by measuring the surface of the kneaded plate-like molded body. 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 when using carbon black as a raw material, even when using carbon black taken out by removing the styrenic resin in the masterbatch, expandable particles, expanded particles, and foamed molded article with an organic solvent, the volume resistivity is The value is about the same.

  In addition, when measuring volume resistivity using a polystyrene-based resin, for the procedure of taking out carbon black by removing the styrene-based resin in the masterbatch, expandable particles, expanded particles, and foamed molded product with an organic solvent, When the carbon black: polystyrene resin = 1: 4 (mass ratio), the removal of the styrene resin is stopped halfway, or the carbon black: polystyrene resin = 1: 4 (mass ratio). You may take the method of adding (dilution) resin. In the case of adopting a method of stopping the removal of the styrene resin in the middle, in order to adjust to carbon black: polystyrene resin = 1: 4 (mass ratio), the masterbatch, expandable particles, expanded particles, carbon in the expanded molded body You may measure the amount of black, and the amount of styrene resin. Although it does not specifically limit as a measuring method of the amount of carbon black, For example, the method etc. which use a differential thermothermal weight simultaneous measuring apparatus are mentioned.

The conductive carbon black may be contained in a form in which primary particles of the conductive carbon black are dispersed in the styrene resin, or an aggregate in which a plurality of primary particles of the conductive carbon black are aggregated in the styrene resin. It may be contained in the form of Preferably, the primary particles of conductive carbon black are contained as agglomerates in which a plurality of agglomerates are aggregated in the styrene resin.
FIG. 1 shows an example of conductive carbon black in which aggregates observed using an electron microscope are formed. The primary particles of conductive carbon black mean substantially circular particles as observed in FIG. By agglomerate is meant a mass of primary particles that appear to overlap each other, as observed in FIG.

The primary particles preferably have an average primary particle size of 18 to 125 nm.
An average primary particle diameter means the average value of the longest diameter of a primary particle, and can take the value of 18-125 nm. However, this does not restrict the primary particles from taking a shape other than spherical and substantially spherical, and the primary particles may take other shapes such as a cylindrical shape and a prismatic shape. When the primary particles have a shape other than a spherical shape or a substantially spherical shape, the average primary particle size means an average value of the longest diameters obtained by approximating the primary particles to a spherical shape. If the average primary particle size is less than 18 nm, moldability may be reduced due to finer bubbles, and if it is greater than 125 nm, moldability may be reduced due to tearing of the bubble film. Specific numerical ranges of the average primary particle diameter include 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, 32-66 nm, 20-125 nm, 25-125 nm, 32-125 nm, 40-125 nm, 50-125 nm, 60-125 nm, 66-125 nm, 73-125 nm, 80-125 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 (i) an average value of the longest diameter of 180 to 500 nm.
The longest diameter means the longest distance between any two points on the outer edge of the aggregate. For example, in FIG. 1, 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 insulating property may not be improved, and when it is larger than 500 nm, bubbles may be broken at the time of foaming and the heat insulating property may not be improved and a good molded product may not be obtained. Specific numerical ranges of the average value of the longest diameter are 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 examples of the average value of the longest diameter include 180, 200, 220, 230, 240, 250, 300, 350, 370, 400, 420, 450, 460, 470, 480, 490, and 500 nm.
The longest diameter of the aggregate is set so as to always overlap the aggregate. In other words, the longest diameter does not pass through the background (styrene resin). For example, in FIG. 1, since the line shown with the broken line has a part which overlaps with a background, it cannot be set as the longest diameter.

In addition, the agglomerates preferably have (ii) a ratio of “average value of longest diameter” to “average primary particle diameter” of 4.0 to 10.0. When the above ratio is less than 4.0, the heat insulating property may not be improved. Specific numerical ranges of the above ratio are 4.0 to 9.0, 5.0 to 9.0, 5.0 to 8.9, 5.0 to 8.5, 5.0 to 8. 0 , 5.0-7.0 , 5.0-6.0 , 5.2-8.9 , 5.5-8.5 , 6.0-8.0,4. 0-10.0, 5.0-10.0, 5.2-10.0, 5.5-10.0, 6.0-10.0 etc. are mentioned. The ratio of the average value of the longest diameter to the specific average primary particle diameter is 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, etc. are mentioned. Detailed measurement methods of the average value of the longest diameter and the average primary particle diameter are described in Examples.

  The conductive carbon black is not particularly limited as long as it has the above volume resistivity, and examples thereof include acetylene black, ketjen black, carbon nanofiber, and carbon nanotube.

  The conductive carbon black content is 0.5 to 25 parts by mass with respect to 100 parts by mass of the styrene resin. When content is less than 0.5 mass part, heat insulation may not fully be improved. On the other hand, when the content exceeds 25 parts by mass, the foam film may be broken, so that the moldability may be reduced and the heat insulation may be inferior. The preferable conductive carbon black content is 0.5 to 15 parts by mass, and the more preferable conductive carbon black content is 0.5 to 10 parts by mass. Specific contents include 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, 7.52, 7.69, 8, 9, 10, 11, 11.11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. It is done.

The conductive carbon black preferably has a specific surface area of 10 to 3000 m ² / g. When the specific surface area is less than 10 m ² / g, the desired heat insulating performance may not be obtained. On the other hand, when the specific surface area exceeds 3000 m ² / g, 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, 210-1500m < 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. As specific surface area values, 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 and the like.

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

(2) Styrenic resin A styrene resin will not be specifically limited if it is resin which can obtain a foaming molding. For example, styrene monomers such as styrene, α-methyl styrene, vinyl toluene, ethyl styrene, i-propyl styrene, t-butyl styrene, dimethyl styrene, bromo styrene, chloro styrene, or a mixture of these monomers The resin derived from is mentioned.
The styrene resin may contain a component derived from a crosslinking agent.
Examples of the crosslinking agent include divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, bis (vinylphenyl) methane, bis (vinylphenyl) ethane, bis (vinylphenyl) propane, bis (vinylphenyl) butane, and divinylnaphthalene. , Divinyl anthracene, divinyl biphenyl, and other bifunctional benzene rings, such as a compound in which a vinyl group is bonded directly, bisphenol A ethylene oxide adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, etc. 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. Examples of other monomers include (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and cetyl (meth) acrylate. Esters, alkyl maleates such as (meth) acrylonitrile, dimethyl maleate and diethyl maleate, alkyl fumarates such as dimethyl fumarate, diethyl fumarate and ethyl fumarate, maleic anhydride, N-phenylmaleimide, (meth) acrylic An acid etc. are mentioned.

Furthermore, resins other than those described above may be included. Other than the above, polyolefin-modified resins such as polyethylene and polypropylene, rubber modified with addition of diene rubbery polymers such as polybutadiene, styrene-butadiene copolymer, ethylene-propylene-nonconjugated diene three-dimensional copolymer Examples thereof include impact-resistant polystyrene resins, polycarbonate resins, polyester resins, polyamide resins, polyphenylene ethers, acrylonitrile-butadiene-styrene copolymers, and polymethyl methacrylate. 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 styrenic resin preferably has a weight average molecular weight of 100,000 to 1,000,000. When the weight average molecular weight is less than 100,000, the strength of the foamed molded product may be lowered. When larger than 1 million, foamability may fall and it may be inferior to lightness. A weight average molecular weight of 150,000 to 800,000 is more preferable, and 200,000 to 500,000 is more preferable.

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

(3) Foaming agent It does not specifically limit as a foaming agent, All can use a well-known thing. In particular, a gaseous or liquid organic compound having a boiling point equal to or lower than the softening point of the styrene resin 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, etc. Low boiling point ether compounds such as alcohols, dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, halogen-containing hydrocarbons such as trichloromonofluoromethane, dichlorodifluoromethane, inorganic gases such as carbon dioxide, nitrogen, ammonia, etc. Can be mentioned. These foaming agents may be used alone or in combination of two or more. Among these, it is preferable to use hydrocarbons from the viewpoint of preventing the destruction of the ozone layer and from the viewpoint of quickly replacing with the air and suppressing the time-dependent change of the foamed molded product. Of the 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 more preferable.
The content of the foaming agent is preferably in the range of 2 to 12% by mass. If it is less than 2% by mass, a foamed molded article having a desired density may not be obtained from the expandable particles. In addition, since the effect of increasing 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 amount is more than 12% by mass, the time required for the cooling step in the production process of the foamed molded product becomes long, and the productivity may decrease. A more preferable content is 3 to 10% by mass, a still more preferable content is 4 to 9% by mass, and a most preferable content is 5 to 8% by mass.
A foaming aid may be used in combination with a foaming agent. Examples of the foaming aid include isobutyl adipate, toluene, cyclohexane, and ethylbenzene.

(4) Other additives Other additives may be included in the expandable particles as necessary. Other additives include plasticizers, flame retardants, flame retardant aids, antistatic agents, spreading agents, foam control agents, fillers, colorants, weathering agents, anti-aging agents, lubricants, antifogging agents, and fragrances. Etc.
Plasticizers include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as cyclohexane, hexane and heptane, adipic acid esters such as diisobutyl adipate, dioctyl adipate and diisononyl adipate, and glycerin diacetomonolaurate. Glycerin fatty acid esters such as glycerin fatty acid esters, dioctyl phthalate, diisononyl phthalate, diisobutyl phthalate and the like, phthalic acid esters such as liquid paraffin and white oil.

Flame retardants include 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.
Examples of the flame retardant aid include organic peroxides such as 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, dicumyl peroxide, and cumene hydroperoxide. .
Examples of the antistatic agent include polyoxyethylene alkylphenol ether, stearic acid monoglyceride, polyethylene glycol and the like.
Examples of the spreading agent include polybutene, polyethylene glycol, glycerin, and silicone oil.

As the air conditioner, 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, Barium sulfate, glass beads, polytetrafluoroethylene, tribasic calcium phosphate, magnesium pyrophosphate, zinc stearate, magnesium stearate and other metal soaps, ethylene bis stearamide, bisamide compounds such as methylene bis stearamide, stearamide Amide compounds such as 12-hydroxystearic acid amide, and fatty acid glycerides such as stearic acid triglyceride and stearic acid monoglyceride.
Examples of lubricants include metal soaps such as zinc stearate and magnesium stearate, bisamide compounds such as ethylenebisstearic acid amide and methylenebisstearic acid amide, stearic acid amides, amide compounds such as 12-hydroxystearic acid amide, stearic acid triglycerides, Examples include fatty acid glycerides such as stearic acid monoglyceride and hydroxystearic acid triglyceride, polyethylene wax, liquid paraffin, and white oil.

(5) Manufacturing method of expandable particle The scope of the present invention includes the above-described manufacturing method of expandable particle.
In one embodiment of the invention,
In a dispersion obtained by dispersing seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin in an aqueous medium, the styrene monomer is added to the seed particles. Impregnating with,
A step of polymerizing the styrenic monomer simultaneously with or after impregnation;
There is provided a method for producing expandable styrenic resin particles comprising a step of impregnating a foaming agent simultaneously with or after polymerization.

The aqueous medium is not particularly limited as long as it is a liquid that can dissolve a water-soluble substance at room temperature, and examples thereof include water, lower alcohols having 1 to 4 carbon atoms, and mixtures thereof. Water is particularly preferable. The amount of the aqueous medium used can be appropriately set by those skilled in the art.
Resins other than styrenic resins may be contained in the resin obtained by polymerization. The kind, physical property, and content of such a resin are as described above.

  This embodiment is an embodiment in which expandable particles are produced using a suspension polymerization method, which is one of the typical methods for producing expandable particles in the art. Hereinafter, the suspension polymerization method will be described in more detail. However, the present embodiment is not limited to the conditions described below.

1. Suspension polymerization method In the suspension polymerization method, a polymerization initiator is dissolved in a styrene monomer, and together with water in which the suspending agent is dispersed, the temperature is increased in a reaction tank, polymerized, and then cooled to produce styrene resin foamable particles. Is the way to get. The method of adding a foaming agent during the polymerization and / or after the polymerization is called a one-stage method. The particles obtained by polymerization without adding a blowing agent are screened, and only the particles in the required particle size range are heated in water in which the suspending agent in the reaction vessel is dispersed, and the blowing agent is added here. The method of impregnating the particles is called a two-stage method (post-impregnation method). Further, small polystyrene particles (seed particles) are put into a reaction vessel containing water in which a suspending agent is dispersed, and after the temperature is raised, styrene monomer in which a polymerization initiator is dissolved is continuously added to the reaction vessel. The method of supplying and polymerizing and growing to the target particle size is called a seed polymerization method. In the seed polymerization method, the foaming agent is added during the polymerization and / or after the completion of the polymerization. The styrenic resin expandable particles of the present invention can be produced by any one of a one-stage method, a two-stage method (post-impregnation method), and a seed polymerization method. In addition, any method has an advantage that true spherical expandable particles can be obtained. A preferable production method includes a seed polymerization method. According to the seed polymerization method, polystyrene particles (master batch) containing conductive carbon black at a 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. However, the present embodiment is not limited to the conditions described below.
(A) Seed polymerization method of suspension polymerization method As this method, styrene resin particles are obtained by absorbing and polymerizing styrene monomer in seed particles containing conductive carbon black and styrene resin. A method of obtaining expandable particles by injecting a foaming agent during the polymerization and / or after completion of the polymerization can be mentioned. In this method, it is easy to obtain expandable particles containing a large amount of conductive carbon black at the center.

(I) Seed particles Seed particles produced by a known method can be used. For example, conductive carbon black and styrene resin are melt-kneaded with an extruder and then extruded into a strand shape to cut the strand. There is an extrusion method for obtaining seed particles. In addition, the resin particles can be used for part or all of the seed particles. 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 adjusted as appropriate according to the average particle size of the resin particles. Further, 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, seed particles are added so 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 insulating property may not be sufficiently improved. On the other hand, when the addition amount exceeds 25 parts by mass, the foam film may be broken, so that the moldability may be reduced and the heat insulating property may be deteriorated. A preferable addition amount of conductive carbon black is 0.5 to 15 parts by mass, and a more preferable addition amount of conductive carbon black is 0.5 to 10 parts by mass. Specific addition amounts include 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, 7.52, 7.69, 8, 9, 10, 11, 11.11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. It is done. In addition, the addition amount can be adjusted so as to have a value approximately the same as the content described for the expandable particles.

(Ii) Polymerization step Each monomer is absorbed by seed particles by supplying a monomer mixture into a dispersion obtained by dispersing seed particles in an aqueous medium, and then each monomer is polymerized. Styrenic 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 100 mass parts in total of the addition amount of a seed particle and a styrene-type monomer. When the amount is less than 50 parts by mass, sufficient foamability may not be obtained. A more preferable content rate is 60 mass parts or more, and a still more preferable content rate is 80 mass parts or more. In addition, the addition amount can be adjusted so as to have a value approximately the same as the content described for the expandable particles.
Examples of the aqueous medium include water and a mixed medium of water and a water-soluble solvent (for example, 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 monomer polymerization. For example, benzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, lauryl peroxide, t-butyl peroxide, t-butyl peroxypivalate, t-butyl peroxyisopropyl Carbonate, t-butyl peroxyacetate, 2,2-t-butylperoxybutane, t-butylperoxy-3,3,5-trimethylhexanoate, di-t-butylperoxyhexahydroterephthalate, 2, Examples thereof include organic peroxides such as 5-dimethyl-2,5-di (benzoylperoxy) hexane and dicumyl peroxide, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. 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. for obtaining a half-life of 10 hours may be used in combination. In addition, a polymerization initiator may be used independently or 2 or more types may be used together.

  A suspension stabilizer may be included in the aqueous medium 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 monomer suspension polymerization. Examples thereof include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, and polyvinyl pyrrolidone, and poorly soluble inorganic compounds such as tricalcium phosphate, magnesium pyrophosphate, magnesium oxide, and hydroxyapatite. And when using a sparingly soluble inorganic compound as said suspension stabilizer, it is preferable to use an anionic surfactant together, and as such anionic surfactant, for example, fatty acid soap, N-acylamino acid or its Salts, carboxylates such as alkyl ether carboxylates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, sulfonates such as dialkylsulfosuccinates, alkylsulfoacetates, α-olefinsulfonates; higher alcohol sulfates Ester salts, secondary higher alcohol sulfates, sulfates such as alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates, etc .; phosphates such as alkyl ether phosphates, alkyl phosphates, etc. Is mentioned.

  Although a polymerization process changes with monomer types to be used, a polymerization initiator seed | species, superposition | polymerization atmosphere, etc., it is normally performed by maintaining 70-130 degreeC heating for 3 to 10 hours. The polymerization step may be performed while impregnating the monomer. In the polymerization step, the total amount of the monomers used may be polymerized in one step, or may be polymerized in two or more steps (including polymerization during the production of seed particles).

(Iii) Foaming agent impregnation step The foamable particles can be obtained by impregnating the above styrene 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 exemplified in the polymerization step. The impregnation temperature of the foaming agent is preferably 60 to 120 ° C. When the temperature is lower than 60 ° C., the time required for impregnating the resin particles with the foaming agent becomes long, and the production efficiency may decrease. On the other hand, when the temperature is higher than 120 ° C., the resin particles may be fused to generate bonded particles. A more preferable 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 styrene resin obtained by polymerization. When the amount is less than 2 parts by mass, a foamed molded article having a desired density may not be obtained from the expandable particles. In addition, since the effect of increasing 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 amount is more than 12 parts by mass, the time required for the cooling step in the production process of the foamed molded product may become long and the productivity may decrease. A more preferable content is 3 to 10 parts by mass, a still more preferable content is 4 to 9 parts by mass, and a most preferable content is 5 to 8 parts by mass. In addition, the quantity of the foaming agent to be impregnated can be adjusted so as to have a value almost the same as the content described for the foamable particles. Further, as described above, a foaming aid may be used in combination with a foaming agent. The types of foaming aids and the like are as described above, and the amount added can be appropriately set by those skilled in the art.

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

  This embodiment is an embodiment in which expandable particles are produced using a melt extrusion method which is one of the typical methods for producing expandable particles in the technical field. Hereinafter, although the melt extrusion method will be described in more detail, the present embodiment is not limited to the conditions described below.

2. Melt extrusion method In the melt extrusion method, polystyrene pellets are supplied to a resin supply device, a foaming agent is press-fitted and kneaded into the polystyrene resin melted in the resin supply device, and the molten resin containing the foaming agent is added to the tip of the resin supply device. It extrudes from the small hole of the die | dye attached to, and it cools after that, and obtains a styrene-type resin foamable particle. A method of directly extruding from a small hole of a die into a cooling liquid, cutting the extrudate with a rotary blade immediately after the extrusion, and cooling the cut particles in the cooling liquid is called a hot cut method. The strand is extruded from the small holes of the die into air in the form of strands, guided into the cooling water tank before the strands are foamed, and after the strands are cooled in the cooling water tank, they are cut into columnar particles. This is called the method (cold cut method). The styrenic resin expandable particles of the present invention can be produced by either the hot cut method or the strand cut method (cold cut method). In addition, any method has an advantage that an arbitrary amount of conductive carbon black can be easily contained in the particles. Further, the conductive carbon black can be uniformly contained in the expandable particles. A preferable production method includes a hot cut method. According to the hot cut method, there is an advantage that substantially spherical expandable particles can be obtained.

Hereinafter, the hot-cut method of the melt extrusion method will be described in more detail. However, the present embodiment is not limited to the conditions described below.
(B) Hot cut method of melt extrusion method As this method, a foaming agent is press-fitted and kneaded into a polystyrene resin melted in a resin supply device, and a molten resin containing the foaming agent is attached to the tip of the resin supply device. The extrudate extruded into the cooling liquid directly from the small holes of the die and cut into the cooling liquid is cut with a rotating blade in the cooling liquid, and the extrudate is cooled and solidified by contact with the liquid to foam. This is a method for obtaining a conductive particle.
In this method, for example, the following manufacturing apparatus can be used. That is, an extruder as a resin supply device, 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 press-fitting the foaming agent through, a cutting chamber in which cooling water is provided in contact with the resin discharge surface provided with a small hole in the die, and the cooling water is circulated and supplied into the chamber, and a small hole in the die A cutter (high-speed rotating blade) that is rotatably provided in the cutting chamber so as to cut the resin extruded from the cutting chamber, and the foaming particles carried along with the flow of cooling water from the cutting chamber are separated from the cooling water. A dehydration dryer with a solid-liquid separation function that obtains foamable particles by dehydration and drying, a water tank for storing cooling water separated by the dehydration dryer with a solid-liquid separation function, and a cooling chamber for 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 production apparatus will be described. First, raw material polystyrene-based resin and carbon black are put into an extruder from a raw material supply hopper. The raw polystyrene resin may be mixed in advance in the form of pellets or granules and then charged from one raw material supply hopper. For example, when multiple lots are used, the supply amount for each lot may be reduced. A plurality of adjusted raw material supply hoppers may be charged and mixed in an extruder. Also, when using a combination of recycled materials from multiple lots, mix the raw materials from multiple lots in advance and remove foreign matter using appropriate sorting means such as magnetic sorting, sieving, specific gravity sorting, and air blowing sorting. It is preferable to keep it. Carbon black may be fed into an extruder as a masterbatch 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 styrene resin. When the addition amount is less than 0.5 parts by mass, the heat insulating property may not be sufficiently improved. On the other hand, when the addition amount exceeds 25 parts by mass, the foam film may be broken, so that the moldability may be reduced and the heat insulation may be inferior. A preferable addition amount of conductive carbon black is 0.5 to 15 parts by mass, and a more preferable addition amount of conductive carbon black is 0.5 to 10 parts by mass. Specific addition amounts include 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, 7.52, 7.69, 8, 9, 10, 11, 11.11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, etc. It is done. In addition, the addition amount can be adjusted so as to have a value approximately the same as the content described for the expandable particles.

  After supplying the raw material into the extruder, the polystyrene resin is heated and melted, and while the molten resin is transferred to the die side, the blowing agent is press-fitted with a high-pressure pump from the blowing agent supply port, and the blowing agent is mixed into the molten resin. The melt is moved to the tip side while further kneading through a foreign matter removing screen provided in the extruder as needed, and the melt added with the foaming agent is pushed out from a small hole in a die attached to the tip of the extruder. .

Those skilled in the art can appropriately set the conditions for injecting the foaming agent into the molten resin obtained by melt kneading. The addition amount of the foaming agent is preferably in the range of 2 to 12 parts by mass with respect to 100 parts by mass of the molten resin. When the amount is less than 2 parts by mass, a foamed molded article having a desired density may not be obtained from the expandable particles. In addition, since the effect of increasing 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 amount is more than 12 parts by mass, the time required for the cooling step in the production process of the foamed molded product may become long and the productivity may decrease. A more preferable content is 3 to 10 parts by mass, a still more preferable content is 4 to 9 parts by mass, and a most preferable content is 5 to 8 parts by mass. In addition, the quantity of the foaming agent to inject | pour can be adjusted so that it may become a value substantially comparable as content described about the expandable particle. Further, as described above, a foaming aid may be used in combination with a foaming agent. The type of foaming aid is as described above, and the amount of foaming aid to be added can be appropriately set by those skilled in the art.

A resin discharge surface with a small hole in the die is placed in a cutting chamber in which cooling water is circulated and supplied into the chamber, and a cutter is provided in the cutting chamber so that the resin extruded from the small hole in the die can be cut. Is rotatably provided. When the melted product with foaming agent added is extruded through a small hole in the die attached to the tip of the extruder, the melt is cut into granules and simultaneously cooled in contact with cooling water to solidify while suppressing foaming. It becomes an expandable particle.
The formed expandable particles are transferred from the cutting chamber along with the flow of cooling water to the dehydrating dryer with a solid-liquid separation function, where the expandable particles are separated from the cooling water and dehydrated and dried. The dried expandable particles are stored in a storage container.
In addition, when adding a flame retardant, the addition time is not particularly limited, but it is preferably added to the extruder together with the raw material.

3. Other methods As an example of other methods, in the melt extrusion method, after obtaining styrene resin particles without press-fitting a foaming agent, the particles are foamed by a suspension polymerization two-stage method (post-impregnation method). Examples thereof include a method of producing a styrene resin foamable particle by impregnating an agent, or a method of producing a styrene resin foamable particle by a seed polymerization method of a suspension polymerization method using this particle as a seed particle. Also by these methods, the styrene resin expandable particles of the present invention can be produced. In addition, any method has an advantage that an arbitrary amount of conductive carbon black can be easily contained in the particles by the melt extrusion method. As a preferable production method, there is a method in which particles containing no foaming agent are obtained by a melt extrusion method, and then styrene resin foamable particles are produced by seed polymerization using the particles as seed particles. According to this method, polystyrene particles (masterbatch) containing conductive carbon black at a high concentration (for example, 20% by mass) can be used as seed particles, and there is an advantage that polymerization inhibition hardly occurs. There is an advantage that expandable particles can be obtained.

(Styrene resin foam particles)
The styrene resin expanded particles (hereinafter referred to as expanded particles) include conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin. The foamed particles can be obtained by foaming (pre-foaming) the foamable particles, and correspond to pre-foamed particles for producing the following foamed molded product.
The conductive carbon black and the styrene resin constituting 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 . When the bulk density is larger than 0.400 g / cm ³ , the lightness of the foamed molded product may be lowered. When the bulk density is less than 0.009 g / cm ³ , the heat insulating performance and mechanical strength of the foamed molded product may be deteriorated. More preferred bulk density of 0.010~0.100g / cm ^3, even more preferred bulk density of 0.01-0.04 / cm ^3, more preferred bulk density 0.011～0.032G / cm ^3, and most preferred bulk density is 0.014~0.029g / 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, 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 bubbles constituting the expanded particles is preferably 50 to 1000 μm. When the average cell diameter is less than 50 μm, the heat insulating property may be lowered. When the average bubble diameter is larger than 1000 μm, the mechanical strength may be lowered. The average cell diameter is more preferably from 100 to 600 μm, still more preferably from 200 to 300 μm. 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 the 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 aging temperature of the expanded particles is preferably 20 to 60 ° C. When the aging temperature is low, the aging time of the expanded particles may be long. On the other hand, if it is high, the foaming agent in the foamed particles may dissipate and the moldability may deteriorate.

(Styrenic resin foam molding)
A styrenic resin foam molded body (hereinafter referred to as a foam molded body) includes a conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin, and includes a plurality of foamed particles fused to each other. It is configured. This foam-molded product can be obtained by foam-molding the foamed particles.
The conductive carbon black and the styrene resin constituting the foamed molded product are the same as the foamable particles.

Preferably, the foamed molded product is obtained by the following formula in the surface color difference measurement based on JIS Z8729-2004 “Color Display Method—L ^* a ^* b ^* Color System”:
31 ≦ ΔE ′ = L ^* + | a ^* | + | b ^* | ≦ 50
(Where ΔE ′ is blackness, L ^* is lightness, a ^* and b ^* are color coordinates)
Satisfies the relational expression indicated by. More preferable ΔE ′ is 32 ≦ ΔE ′ ≦ 45, and still more preferable ΔE ′ is 32 ≦ ΔE ′ ≦ 35. In the case of ΔE ′ <31, the heat insulating property may be lowered. On the other hand, in the case of ΔE ′> 50, the heat insulating property may be lowered. (1) In order to reduce ΔE ′, depending on whether carbon black closer to black is selected, the content of carbon black in the foam molded body is increased, or the density of the foam molded body is increased. Can be achieved. (2) In order to increase ΔE ′, depending on whether carbon black closer to gray is selected, the content of carbon black in the foam molded body is reduced, or the density of the foam molded body is reduced. Can be achieved. Specific blackness values include 31, 32, 33, 34, 35, 38, 40, 43, 44, 45, 46, 47, 48, 49, 50, and the like. Detailed blackness measurement methods are described in the Examples.

  The foamed molded product may further contain a flame retardant. As the flame retardant, the same ones described for the above expandable particles can be used, but tetrabromocyclooctane or tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) is particularly preferred. preferable. Content of a flame retardant is 0.5-10 mass parts with respect to 100 mass parts of foaming moldings, Preferably it is 2-8 mass parts. Specific values of the flame retardant content include 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 parts by mass, and the like.

  Preferably, the foam-molded article is a heat insulating material for a living space in which the total content of aromatic organic compounds composed of a styrene 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 sick house syndrome, which has been recently requested, and to provide a more comfortable living space. More preferably, it is 1750 ppm or less, More preferably, it is 1500 ppm or less, Most preferably, it is 500 ppm or less, Most preferably, it is 300 ppm or less. By selecting a resin raw material with a low content of aromatic organic compounds consisting of styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene, and benzene as the raw material polystyrene resin, Thus, it is possible to obtain styrene resin foamable particles, foamed particles, foamed molded products, and heat insulating materials for living spaces without mixing the aromatic organic compound. In the case of foamed particles, foamed molded products, and heat insulating materials for living spaces obtained from the same styrenic resin foamable particles, the total content of the aromatic organic compounds is a comparable value. Styrenic resin expandable 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 spaces. In addition, a melt extrusion method is preferable as a production method for obtaining styrene resin expandable particles having a small total content of the aromatic organic compound. Detailed methods for measuring the total content of aromatic organic compounds are described in the Examples.

The foamed molded body preferably has a density of 0.010 to 0.400 g / cm ³ . If the density is greater than 0.400 g / cm ³ , the lightness may be reduced. When the density is less than 0.010 g / cm ³ , the heat insulating performance and mechanical strength may be lowered. A more preferable density is 0.011 to 0.100 g / cm ³ , an even more preferable density is 0.012 to 0.04 g / cm ³ , and a still more preferable density is 0.0125 to 0.033 g / cm ³ . The most preferable density is 0.015 to 0.030 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, 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 bubble diameter) of the bubbles constituting the foamed molded product is 50 to 1000 μm. When the average cell diameter is less than 50 μm, the heat insulating property may be lowered. When the average bubble diameter is larger than 1000 μm, the mechanical strength may be lowered. The average cell diameter is more preferably from 100 to 600 μm, still more preferably from 200 to 300 μm. 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 foamed molded product is 0. It preferably exhibits a thermal conductivity of 0 34 W / mk or less. Thermal conductivity is 0. If it exceeds 0 34 W / mk, it may not be possible to provide a foamed molded article having sufficient heat insulation. A more preferred thermal conductivity is 0. 0 33 W / mk or less, and more preferable thermal conductivity is 0. 0 32 W / mk or less. Specific values of thermal conductivity are 0. 0 34, 0 . 0 339, 0 . 0 338, 0 . 0 337, 0 . 0 336, 0 . 0 335, 0 . 0 334, 0 . 0 333, 0 . 0 332, 0 . 0 331, 0 . 0 33, 0 . 0 329, 0 . 0 328, 0 . 0 327, 0 . 0 326, 0 . 0 325, 0 . 0 324, 0 . 0 323, 0 . 0 322, 0 . 0 321, 0 . 0 32, 0 . 0 319, 0 . 0 318, 0 . 0 317, 0 . 0 316, 0 . 0 315, 0 . 0 314, 0 . 0 313, 0 . 0 312, 0 . 0 311, 0 . 0 31, 0 . 0 309, 0 . 0 308, 0 . 0 307, 0 . 0 306, 0 . 0 305, 0 . 0 304, 0 . 0 303, 0 . 0 302, 0 . 0 301, 0 . 0 30 or the like.

The foamed molded product 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 insulating property may be lowered. More preferable water absorption is less than 0.4 g / 100 cm ² , still more preferable water absorption is less than 0.3 g / 100 cm ² , and even more preferable water absorption is less than 0.2 g / 100 cm ² . Specific water absorption values include 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, etc. Is mentioned.

Preferably, the foamed molded article exhibits a ratio A / B of 0.8 to 2.0 in absorbance A at a wave number of 1000 cm ⁻¹ and absorbance B at a wave number of 500 cm ⁻¹ obtained by transmission infrared analysis. When the absorbance ratio A / B <0.8 or when the absorbance ratio A / B> 2.0, sufficient heat insulation may not be obtained. (1) The absorbance ratio A / B can be reduced by increasing the amount of the infrared shielding agent added. (2) Increasing the absorbance ratio A / B can be achieved by increasing the addition amount of the infrared shielding agent, decreasing the bubble diameter, or the like. A more preferred absorbance ratio A / B is 0.81 to 1.80, and a further preferred 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.

Absorbance A means the absorbance at a wave number of 1000 cm ⁻¹ obtained by transmission infrared analysis. The preferred absorbance A is 0.8 or more. When the absorbance A is less than 0.8, the heat insulation is poor. More preferable 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. 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, and the like.

Further, the absorbance B means the absorbance at a wave number of 500 cm ⁻¹ obtained by transmission infrared analysis. The preferred absorbance B is 0.5 or more. When the absorbance B is less than 0.5, the heat insulating property is lowered. More preferable absorbance B is 0.55 or more. Specific values of absorbance B are 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 and the like.
Detailed methods for measuring absorbances A and B are described in the Examples.

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

  The foamed molded product can be used for various applications that require heat insulation. For example, wall insulation, floor insulation, roof insulation, automotive insulation, warm water tank insulation, piping insulation, solar system insulation, water heater insulation, food and industrial products, etc. It can be used for containers, packing materials for fish and agricultural products, embankment materials, tatami core materials, etc. The foamed molded product can take a shape corresponding to the intended use. In particular, it can be suitably used as a heat insulating material for living spaces such as a heat insulating material for walls, a heat insulating material for floors, a heat insulating material for roofs, and a heat insulating material for automobiles.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
<Volume resistivity of carbon black measured using polyethylene resin>
Here, the volume resistivity is the raw material carbon black, or when the raw material carbon black is added to the master batch, expandable particles, expanded particles, and expanded molded article, the master batch, expandable particles, Carbon black taken out by removing the styrene resin in the foamed particles and the foamed molded article with toluene as an organic solvent was melt kneaded with the polyethylene resin (carbon black: polyethylene resin = 1: 4 (mass ratio). )), The value obtained by measuring the surface of the kneaded product.
Specifically, a polyethylene resin and carbon black were sufficiently melt-kneaded using an extruder and formed into a film shape, and measured according to the method described in JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. To do. That is, using a test device (advantest digital ultra-high resistance / microammeter R8340 and resiliency chamber R12702A), the electrode was pressed against the sample sample with a load of about 30 N, and the resistance after charging at 500 V for 1 minute. The value is measured and calculated by the following formula. The sample sample has a width of 100 × length of 100 × original thickness (10 or less) mm. After conditioning for 24 hours or more at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5%, the test environment is measured at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5%. The number of test pieces is five, and the average value is 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 specimen (cm)
Rv: Volume resistance (Ω)

<Volume resistivity of carbon black measured using polystyrene resin>
Here, the volume resistivity is the raw material carbon black, or when the raw material carbon black is added to the master batch, expandable particles, expanded particles, and expanded molded article, the master batch, expandable particles, The carbon black taken out by removing the styrene resin in the foamed particles and the foamed molded article with toluene as an organic solvent was melt kneaded with the polystyrene resin (carbon black: polystyrene resin = 1: 4 (mass ratio). )), The value obtained by measuring the surface of the kneaded product.
Specifically, a resistivity test by a four-probe method of conductive plastic is performed on a plate-shaped molded body of a mixture of carbon black and polystyrene resin (carbon black: polystyrene resin = 1: 4 (mass ratio)). Measurement is performed in accordance with the method (JIS K7194). The test apparatus uses a low resistivity meter Lorester GP MCP-T600 manufactured by Mitsubishi Chemical Corporation, and the sample sample has a width of 80 × length of 50 × original thickness (20 or less) mm. The sample sample is conditioned at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5% for 24 hours or more, and then measured as a test environment at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 5%. The volume resistivity is calculated from the following equation by measuring the resistance values at five measurement positions according to JIS K 7194 on the surface of the sample. The average value is defined as the volume resistivity (Ω · cm) of carbon black.
ρv = V / I × RCF × t
ρv: Volume resistivity (Ω · cm)
V / I: Resistance (Ω)
RCF: Correction coefficient depending on measurement position and sample thickness t: Thickness of test piece (cm)

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

(Measurement condition)
Equipment used: High-speed GPC equipment: HLC-8320GPC EcoSEC system manufactured by Tosoh Corporation (with built-in RI detector)
Guard column: Tosoh TSK guard column SuperHZ-H (4.6 mm ID × 2 cmL) × 1 Column: Tosoh TSKgel SuperHZM-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 Runtime: 25 minutes Sampling pitch: 200 msec

(Create a calibration curve)
As standard polystyrene samples for calibration curves, the weight average molecular weights of trade names “TSK standard POLYSTYRENE” manufactured by Tosoh Corporation are 5,480,000, 3,840,000, 355,000, 102,000, 37,900, 9 , 100, 2,630, and 500, and standard polystyrene samples having a weight average molecular weight of 1,030,000 with a trade name “Shodex STANDARD” manufactured by Showa Denko KK are used.

  The method of creating a calibration curve is as follows. The above standard polystyrene samples for calibration curves are group A (with a weight average molecular weight of 1,030,000), group B (weight average molecular weights of 3,840,000, 102,000, 9,100, 500) and group C. (The weight average molecular weight is 5,480,000, 355,000, 37,900, 2,630). Group A is weighed 5 mg and then dissolved in 20 mL of tetrahydrofuran, Group B is also weighed 5 to 10 mg each and then dissolved in 50 mL of tetrahydrofuran, and Group C is also weighed 1 to 5 mg each and then dissolved in 40 mL of tetrahydrofuran. The standard polystyrene calibration curve was prepared by injecting 50 μL of the prepared A, B, and C solutions. From the retention time obtained after measurement, a calibration curve (tertiary equation) was transferred to the HLC-8320GPC dedicated data analysis program GPC workstation (EcoSEC-WS). The measurement curve is obtained by using the calibration curve.

<Measurement method of average primary particle size>
Using a cutter knife, the center of the expandable particles is cut out, and the skin portion of the expanded particles and the expanded molded body is cut out as a measurement sample. The cut sample is fixed to the cryosample table with an adhesive, and then ultrathin using an ultramicrotome (Leica Microsystems, LEICA ULTRACUT UCT) and a frozen section preparation system (Leica Microsystems, LEICA EM FCS). A section (thickness 90 nm) is prepared. Next, using a transmission electron microscope (H-7600, manufactured by Hitachi High-Technologies Corporation), an ultrathin section is photographed (photographing magnification: 50,000 times). At least 200 carbon blacks are photographed per sample, the diameter of each particle is measured, and the average value thereof is calculated. In addition, it is desirable to measure the part which can be recognized clearly as a primary particle, without an outer edge missing.

<Measurement method of carbon black content in resin>
The amount of carbon black in the resin is measured using a differential thermothermal gravimetric simultaneous measurement apparatus TG / DTA6200 type (manufactured by SII Nano Technology). For example, in the case of foamable particles, foamed particles, foamed molded products, etc. containing a foaming agent or an organic solvent in the resin, the foaming agent in the resin can be left in a constant temperature bath at 120 ° C. for 2 hours. Samples from which organic solvents have been removed are used as measurement samples. About 15 mg of the sample is filled so that there is no gap at the bottom of the platinum measurement container, and the measurement is performed using alumina as a reference material. 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 raised from 520 ° C. to 800 ° C. at a rate of 10 ° C./min and an Air flow rate of 160 mL / min. A TG curve (vertical axis: TG (%), horizontal axis: temperature (° C.)) was obtained, and based on this, the weight loss of the sample when the temperature was raised from 520 ° C. to 800 ° C. was calculated, and the amount of carbon black w (mass%) ).
At this time, the mass ratio between the carbon black and the styrene resin has the following relationship.
Carbon black: Styrenic resin = 1: (100 / w-1)
w: value of mass% of carbon black obtained from the measurement result In addition, if the foamed particles, the foamed molded product and the heat insulating material for living space obtained from the same styrenic resin foamable particles, the carbon black and the styrenic resin The mass ratio is a similar value.

<Bulk density of expanded particles>
The bulk density of the expanded particles is measured according to JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. Specifically, first, Wg is collected using the expanded particles as a measurement sample, and the measurement sample is naturally dropped into a measuring cylinder. The volume Vcm ³ of the measurement sample dropped into the graduated cylinder is measured using an apparent density measuring instrument based on JIS K6911. By substituting Wg and Vcm ³ into the following formula, the bulk density of the expanded particles is calculated.
Bulk density of expanded particles (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)

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

<Average bubble diameter>
The average cell diameter is measured according to the test method of ASTM D2842-69. Using a razor blade, obtain a cross-section of the molded body of the foamed particles and any part of the foamed molded body. Using the scanning electron microscope (JSM-6360LV, manufactured by NEC Corporation), an image obtained by enlarging the cut surface by 100 times is created.
Next, a straight line of 60 mm is drawn at an arbitrary 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 the 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 multiple of image)
The average bubble diameter (D) of this bubble is calculated by the following formula.
Average bubble diameter D (μm) = t / 0.616
The above operation is performed with N number of 10, and the average value is defined as the average bubble diameter.

<Thermal conductivity>
A test piece having a rectangular parallelepiped shape having a length of 200 mm, a width of 200 mm, and a thickness of 30 mm is cut out from the foamed molded body. Next, the cut out test piece is allowed to stand for 72 hours in a constant temperature bath at 60 ° C. to remove the foaming agent contained in the foamed molded product. Thereafter, curing is performed for 24 hours or more at a temperature of 23 ° C. ± 1 ° C. and a humidity of 50 ± 10% to obtain a test piece for measuring thermal conductivity. The thermal conductivity (W / m · K) of the test specimen for measurement is measured at a measurement temperature of 23 ° C. by a flat plate heat flow meter method according to JIS A1412-2 (1999 “Foamed plastic insulation material”). Rate is an indicator of thermal insulation.
From the value of the obtained thermal conductivity (W / m · K), the heat insulation is evaluated according to the following criteria.
0.0310 (W / m · K) or less: Thermal insulation is further improved (A)
0.0310 and 0.0320 or less: better thermal insulation (B)
More than 0.0320 and 0.0340 or less: Excellent heat insulation (C)
Exceeds 0.0340 (W / m · K): poor heat insulation (D)
In the present invention, the value of the thermal conductivity of the foamed molded product is a value after removing the foaming agent contained in the foamed molded product. When measured without removing the foaming agent in the foamed molded product, the thermal conductivity of the foaming agent such as butane and pentane is lower than the thermal conductivity of air, so the value of the thermal conductivity of the foamed molded product is , 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.

<Expandable particles, expanded particles, and longest diameter of carbon black agglomerates in expanded molded body>
Using a cutter knife, the expandable particles are cut out at the center of the particles, and the expanded particles and the expanded molded body are cut out of the skin portion to be used as a measurement sample. The cut sample is fixed to the cryosample table with an adhesive, and then ultrathin using an ultramicrotome (Leica Microsystems, LEICA ULTRACUT UCT) and a frozen section preparation system (Leica Microsystems, LEICA EM FCS). A section (thickness 90 nm) is prepared. Subsequently, using a transmission electron microscope (H-7600, manufactured by Hitachi High-Technologies Corporation), an ultrathin section is photographed (imaging magnification: 10,000 times). Photograph at least 200 independent separate aggregates per sample. In the photographed image, the longest diameter of the distance between any two points on the outer edge of the aggregate that the carbon black primary particles appear to overlap with each other was taken as the longest diameter of the aggregate, and the average value thereof was calculated. The longest diameter connecting the two points is set so as to always overlap the primary particles on the photograph. That is, the longest diameter does not pass through the background of the photograph.

<Blackness of foam molding>
The blackness ΔE ′ of the foamed molded product is evaluated by color difference measurement based on JIS Z8729-2004 “Color Display Method—L ^* a ^* b ^* Color System”.
For the measurement, a color difference meter (manufactured by Konica Minolta, model: CR-400) and a standard white plate calibration plate (Y: 94.3, x: 0.3144, y: 0.3208) are used for standardization.
Specifically, from any 10 points on the vertical and horizontal surfaces of the foamed molded product, the measurement area was measured as φ8 mm, and the average value was calculated from the lightness L ^* value, color coordinate a ^* value, and b ^* value. ΔE ′ is calculated as the degree.
ΔE ′ = L ^* + | a ^* | + | b ^* |
From the obtained ΔE ′, the blackness is evaluated according to the following criteria.
31 ≦ ΔE ′ ≦ 50: Good (◯)
ΔE ′ <31 and 50 <ΔE ′: Defect (×)

<Measurement method of absorbance>
A sample having a thickness of 1.0 mm ± 0.1 mm is obtained from an arbitrary portion of the obtained foamed molded article. Next, the absorbance of the transmitted infrared of the sample is measured by the following method.
・ Fourier transform infrared spectroscopic analyzer NICOLET iS5 (manufactured by Thermo Fisher Scientific)
Measurement method: Transmission method Measurement wave number region: 4000 cm ^{−1 to} 400 cm ⁻¹
-Wave number dependence of measurement depth: No correction-Detector: DTGSKBr
・ Resolution: 4cm ^-1
・ Number of integration: 16 times (same for background measurement)

<Measurement method of water absorption>
The water absorption of the foamed molded product was measured according to JIS A9511: 2006R foamed plastic heat insulating material measuring method B. Three test pieces having a 100 × 100 × 25 mm full-cut surface were immersed in fresh water for 10 seconds, then immersed in ethanol for 10 seconds, and further allowed to stand at room temperature (23 ° C.) for 60 minutes. The reference mass (m0) And Next, after immersing in fresh water again and allowing it to absorb water for 24 hours, the mass (m1) is measured by the same method as the reference mass measurement.
About three test pieces, W is calculated with the following formula | equation, respectively, and let the average value be water absorption (g / 100cm < ² >).
W = (m1-m0) / A × 100
m1 (g): Mass after absorbing water for 24 hours m0 (g): Reference mass A (cm ² ): Total surface area

<Measurement method and evaluation of flame retardancy>
Five test pieces having a rectangular parallelepiped shape having a length of 200 mm, a width of 25 mm, and a height of 10 mm are cut out from the obtained foamed molded article with a vertical cutter. After the cut material is cured in an oven at 60 ° C. for 1 day, the individual flame-out time is measured according to the measurement method A of JIS A9511-2006. The average value of the individual flame extinguishing times of 5 test pieces is taken as the flame extinguishing time. In addition, the flame retardance was evaluated according to the following criteria from the flame extinguishing time.
Good (○) ・ ・ ・ Extinguishing time 1.5 seconds to less than 3.0 seconds Very good (◎) ・ ・ ・ Extinguishing time less than 1.5 seconds Unmeasured (-) Absent

<Total content of aromatic organic compound>
The total content of the aromatic organic compound is a value measured by the following << Method for measuring volatile organic compound (VOC) content >>.
<< Measurement Method of Volatile Organic Compound (VOC) Content >>
Weigh accurately 1 g of foamed molded product, add 1 mL of dimethylformamide solution containing 0.1% by volume of cyclopentanol as an internal standard solution, and then add dimethylformamide to the dimethylformamide solution to prepare 25 mL of the measurement solution. Then, 1.8 μL of this measurement solution was supplied to a 230 ° C. sample vaporization chamber, and a gas chromatograph (manufactured by Shimadzu Corporation, trade name “GC-14A”) was detected under the following measurement conditions. Based on the calibration curve of each volatile organic compound measured in advance, the amount of volatile organic compound is calculated from each chart, and the amount of volatile organic compound in the foamed molded product is calculated. When calculating the amount of the volatile organic compound in the expandable particles, 1 g of the expandable particles is precisely weighed and measured in the same manner.
Detector: FID
Column: GL Sciences (3mmφ × 2.5m)
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 (40mL / min)
In addition, among the volatile organic compound (VOC) content described above, the total amount of each volatile organic compound corresponding to the aromatic organic compound is defined as “total content of aromatic organic compound”.

Example 1
7995 g of polystyrene resin having a weight average molecular weight of 300,000, 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), ethylene bis stearamide (Kao Corporation) (Product: Kao Wax EB-FF) is supplied to a twin-screw extruder, melt-kneaded at 250 ° C., extruded into a strand from the extruder, the strand is cut into predetermined lengths, and cylindrical polystyrene Resin seed particles (diameter: 0.8 mm, length: 0.8 mm) were prepared.
Next, 2000 g of water, 300 g of cylindrical polystyrene-based 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 heated to 72 ° C. with stirring to obtain a dispersion. Was made.

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 were dissolved in 100 g of styrene. The dispersion was fed with stirring.
Then, the temperature of the dispersion was increased from 72 ° C. to 90 ° C. after 60 minutes had passed since the styrene was supplied 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 supplying all the styrene, the mixture was stirred at a constant temperature of 90 ° C. for 1 hour, then heated to 125 ° C. and stirred for 2 hours. After stirring, 1200 g of polystyrene resin particles were obtained by cooling.

Next, 1200 g of the obtained polystyrene-based resin particles, 2000 g of water, 6 g of magnesium pyrophosphate and 0.3 g of sodium dodecylbenzenesulfonate are supplied to a polymerization vessel equipped with a stirrer and heated to 70 ° C. with stirring to obtain a dispersion. Was made.
Next, 10.8 g of tetrabromocyclooctane as a flame retardant and 3.6 g of dicumyl peroxide as a flame retardant aid were supplied into the dispersion, and the polymerization vessel was sealed and heated to 90 ° C.
Subsequently, 108 g of butane was injected into the polymerization vessel and held for 6 hours to impregnate the polystyrene resin particles with butane. After impregnation, the inside of the polymerization vessel was cooled to 25 ° C. to obtain styrene resin expandable particles. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 19 (mass ratio). The resulting styrene resin expandable particles had a weight average molecular weight of 790,000. The obtained styrene resin expandable particles were spherical.

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

Then, the styrene resin expandable 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-expanded particles were filled in a mold and heated and foamed to obtain a foamed molded product having a length of 400 mm × width of 300 mm × thickness of 30 mm. The foamed molded product was dried in a drying chamber at 50 ° C. for 6 hours, and then the density of the foamed molded product was measured and found to be 0.020 g / cm ³ . This foamed molded article was excellent in appearance without shrinkage. The average cell diameter of the foamed molded product 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-expanded particles was changed from 0.019 g / cm ³ to 0.016 g / cm ^3. In the same manner as in Example 1 except that the density of the foamed molded product was changed from 0.020 g / cm ³ to 0.017 g / cm ³ , styrene-based resin foamable particles, pre-expanded particles, and foamed molded products were obtained. . The weight average molecular weight of the styrenic resin expandable particles obtained in this process was 750,000, and was spherical. Moreover, the average cell diameter of the obtained foaming molding was 590 micrometers.
(Example 3)
Pre-expanded particles having a bulk density of 0.019 g / cm ³ obtained in Example 1 were aged at 20 ° C. for 24 hours, and then heated again to obtain pre-expanded particles having a bulk density of 0.0135 g / cm ³ . . The pre-expanded particles were aged at 20 ° C. for 24 hours. Next, a foamed molded article having a density of 0.0143 g / cm ³ was obtained by molding in the same manner as in Example 1. This foam molded article had an average cell diameter of 130 μm.

Example 4
Nippon Pigment Co., Ltd., carbon black-containing polystyrene resin masterbatch (product name: EX4050B) (average primary particle size 55 nm, specific surface area 28 m ² / g, sulfur content 4000 ppm, ash content 0.03% carbon black 20% by mass) ) Is melt-kneaded at 250 ° C. and extruded from the extruder into strands, and the strands are cut into predetermined lengths to obtain cylindrical polystyrene resin seed particles (diameter). : 0.8 mm, length: 0.8 mm), except that the styrenic resin expandable particles, pre-expanded particles, and foamed molded article were obtained in the same manner as in Example 1.

(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 having a weight average molecular weight of 200,000 (product name “HRM-10N”, manufactured by Toyo Styrene Co., Ltd.) 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 foam nucleating agent, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) as flame retardant Ether) 5 parts by mass, these were continuously fed to a single screw extruder having a diameter of 90 mm at 150 kg per hour. The temperature inside the extruder was set to a maximum temperature of 220 ° C., and after the resin was melted, 6 parts by mass of isopentane was injected from the middle of the extruder as a foaming agent to 100 parts by mass of the resin. The resin and foaming agent are kneaded and cooled in the extruder, the resin temperature at the tip of the extruder is maintained at 170 ° C., the pressure at the resin introduction part of the die is maintained at 15 MPa, the diameter is 0.6 mm, and the land length is 3 From the die having 200 small holes of 0.0 mm, the foaming agent-containing molten resin is extruded into the cutting chamber connected to the discharge side of this die and circulating water at 30 ° C. The extrudate was cut with a high-speed rotary cutter having a blade. While the cut particles were cooled with circulating water, they were conveyed to a particle separator, and the particles were separated from the circulating water. Furthermore, the collected particles were dehydrated and dried to obtain styrene resin foamable particles. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 19 (mass ratio). The obtained styrenic resin expandable particles were almost spherical without deformation and beard, and the average particle size was about 1.1 mm.
Polyethylene glycol 0.03 parts by mass, zinc stearate 0.15 parts by mass, stearic acid monoglyceride 0.05 parts by mass, hydroxystearic acid triglyceride 0.05 parts by mass with respect to 100 parts by mass of the obtained styrenic resin expandable particles. The portion was uniformly coated on the entire surface of the styrene resin expandable particles.
By heating the styrene resin foamable particles produced as described above, the foamed particles were 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-expanded particles were filled in a mold and heated and foamed to obtain a foamed molded product having a length of 400 mm × width of 300 mm × thickness of 30 mm. The foamed molded product was dried in a drying chamber at 50 ° C. for 6 hours, and then the density of the foamed molded product was measured and found to be 0.020 g / cm ³ . This foamed molded article was excellent in appearance without shrinkage.

(Example 6)
The carbon black-containing polystyrene resin masterbatch used in Example 4 was used for 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.) EX4050B) (average primary particle diameter 55 nm, specific surface area 28 m ² / g, sulfur content 4000 ppm, ash content 0.020% carbon black 20% by mass) 25 parts by mass, fine powder talc 0.5 as inorganic foam nucleating agent Styrene-based resin expandable particles and pre-expanded particles in the same manner as in Example 5 except for changing to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant A foamed molded product was obtained. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 19 (mass ratio). The obtained foamed 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 foamed molded product was obtained.
(Example 8)
Styrenic resin expandable particles and pre-expanded particles in the same manner as in Example 6 except that pre-expanded particles having a bulk density of 0.024 g / cm ³ were prepared and a foamed molded article having a density of 0.025 g / cm ³ was obtained. A foamed molded product was obtained.

Example 9
The feedstock to the extruder is 82.5 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 (EX4050B), and fine powder talc as an inorganic foam nucleating agent. 5 parts by mass, styrene-based resin expandable particles, pre-expanded in the same manner as in Example 6 except for changing to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant Particles and foamed moldings were obtained. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 39 (mass ratio). The obtained foamed molded article was excellent in appearance without shrinkage.

(Example 10)
The feedstock to the extruder is 35 parts by mass of carbon black-containing polystyrene resin masterbatch (EX4050B) with respect to 65 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000, 0.5 parts by mass of fine powder talc as an inorganic foam nucleating agent, Except changing to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant, styrene-based resin expandable particles, pre-expanded particles, and foam molding in the same manner as in Example 6. Got the body. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 13.3 (mass ratio). The obtained foamed molded article was excellent in appearance without shrinkage.

(Example 11)
The feedstock to the extruder is 50 parts by mass of a carbon black-containing polystyrene resin masterbatch (EX4050B) with respect to 50 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000, 0.5 parts by mass of fine powder talc as an inorganic foam nucleating agent, Except changing to 5 parts by mass of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant, styrene-based resin expandable particles, pre-expanded particles, and foam molding in the same manner as in Example 6. Got the body. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 9 (mass ratio). The obtained foamed molded article was excellent in appearance without shrinkage.

(Example 12)
The polystyrene-based resin masterbatch (product name: EX4050A, average primary particle size 40 nm, specific surface area 254 m ² / g) manufactured by Nippon Pigment Co., Ltd. is used for the feedstock to the extruder with respect to 75 parts by mass of virgin polystyrene having a weight average molecular weight of 200,000. 20 parts by weight of carbon black) 25 parts by weight, 0.5 parts by weight of fine powder talc as an inorganic foam nucleating agent, and 5 parts by weight of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether) as a flame retardant Except changing, it carried out similarly to Example 6, and obtained the styrene resin expandable particle, the pre-expanded particle, and the foaming molding. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 19 (mass ratio). The obtained foamed molded article was excellent in appearance without shrinkage.

(Example 13)
The feedstock to the extruder is 95 parts by weight of virgin polystyrene having a weight average molecular weight of 200,000, 5 parts by weight of conductive carbon black (average primary particle size 35 nm, specific surface area 80 m ² / g), fine powder as inorganic foam nucleating agent Styrenic resin expandable 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 used. Thus, pre-expanded particles and a molded foam were obtained. The obtained styrene resin expandable particles were carbon black: styrene resin = 1: 19 (mass ratio). The obtained foamed molded article was excellent in appearance without shrinkage.

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

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

  Various physical properties of the expandable particles, the expanded particles and the foamed molded product and the thermal conductivity of the foamed molded product are shown 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 expressed as “volume resistivity (PE)”, and the volume resistivity measured using a polystyrene resin is expressed as “volume resistivity (PS)”. . Moreover, the cross section of the foaming molding produced in Example 1 and the foaming particle of Example 2 was observed with the electron microscope. The images are shown in FIGS.

From Table 3, it can be seen that a foamed molded article having good heat insulation can be obtained by including conductive carbon black having a volume resistivity (PE and / or PS) of 1.0 × 10 ⁴ Ω · cm or less. .

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

  The resin and foaming agent are kneaded and cooled in the extruder, the resin temperature at the tip of the extruder is maintained at 170 ° C., the pressure at the resin introduction part of the die is maintained at 15 MPa, the diameter is 0.6 mm, and the land length is 3 From the die having 200 small holes of 0.0 mm, the foaming agent-containing molten resin is extruded into the cutting chamber connected to the discharge side of this die and circulating water at 30 ° C. The extrudate was cut with a high-speed rotary cutter having a blade. While the cut particles were cooled with circulating water, they were conveyed to a particle separator, and the particles were separated from the circulating water. Further, the collected particles were dehydrated and dried to obtain expandable styrene resin particles.

The obtained expandable styrene resin particles were carbon-based infrared shielding agent: styrene resin = 1: 19 (mass ratio). The obtained expandable styrenic resin particles were almost spherical with no deformation or beard, and the average particle size was about 1.1 mm. Polyethylene glycol 0.03 parts by mass, zinc stearate 0.15 parts by mass, stearic acid monoglyceride 0.05 parts by mass, hydroxystearic acid triglyceride 0.05 parts by mass with respect to 100 parts by mass of the obtained expandable styrene resin particles. The part was uniformly coated on the entire surface of the expandable styrene resin particles. By heating the expandable styrene resin particles produced as described above, the foamed styrene resin particles were prefoamed 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-expanded particles were filled in a mold and heated and foamed to obtain a foamed molded product having a length of 400 mm × width of 300 mm × thickness of 30 mm.

The foamed molded product was dried in a drying chamber at 50 ° C. for 6 hours, and then the density of the foamed molded product was measured and found to be 0.020 g / cm ³ . This foamed molded article was excellent in appearance without shrinkage. The obtained foamed molded product was sliced to a thickness of 1.0 ± 0.1 mm using a ham slicer to obtain a sample for measuring absorbance. The absorbance obtained by transmission infrared absorption analysis of this foamed molded product 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 absorbance ratio (A / B) was 1.26. Further, the thermal conductivity of the foamed molded article was excellent at 0.031 W / mk. Furthermore, 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)
A polystyrene resin masterbatch (product name: EX4050B, average primary particle diameter 55 nm, manufactured by Nippon Pigment Co., Ltd.) with respect to 75 parts by mass of polystyrene (product name “HRM-10N”, manufactured by Toyo Styrene Co., Ltd.) having a weight average molecular weight of 200,000 A foamed molded product was obtained in the same manner as in Example 14 except that 25 parts by mass of carbon black (containing 20% 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 absorbance ratio (A / B) was 1.14. The foam molded body had a thermal conductivity of 0.032 W / mk and a water absorption of 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: EX4050A, average primary particle size 15 nm, manufactured by Nippon Pigment Co., Ltd.) with respect to 75 parts by mass of polystyrene (product name “HRM-10N”, manufactured by Toyo Styrene Co., Ltd.) 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 carbon black (containing 20% 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 absorbance ratio (A / B) was 1.14. The foam molded article had a thermal conductivity of 0.032 W / mk and a water absorption of 0.11 g / 100 cm ² . The average value of the longest diameter of the aggregate was 278 nm.
(Example 18)
A foam molded article was obtained in the same manner as in Example 14 except that an average primary particle size 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 absorbance ratio (A / B) was 1.15. The foam molded article had a thermal conductivity of 0.030 W / mk and a water absorption of 0.1 g / 100 cm ² . The average longest diameter of the agglomerates was 255 nm.

(Example 19)
A foam molded article was obtained in the same manner as in Example 14 except that ketjen black (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 absorbance ratio (A / B) was 0.82. The foam molded body had a thermal conductivity of 0.030 W / mk and a water absorption of 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 absorbance ratio (A / B) was 2.54. The water absorption of the foamed molded product was 0.20 g / 100 cm ² . The thermal conductivity of the foamed molded article was 0.038 W / mk, which was insufficient.
(Comparative Example 5)
A foam molded article was obtained in the same manner as in Example 12 except that furnace black (Mitsubishi Chemical Corporation: # 970) having an average primary particle size 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 absorbance ratio (A / B) was 2.20. The water absorption of the foamed molded product was 0.22 g / 100 cm ² . The thermal conductivity of the foamed molded product was 0.037 W / mk, which was insufficient.

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

Claims (20)

A conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less, a styrene resin, and a foaming agent;
The primary particles of the conductive carbon black are contained as agglomerates agglomerated in the styrenic resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The agglomerates are
(I) an average value of the longest diameter of 180 to 500 nm;
(Ii) possess a ratio of the average value of the longest diameter to said average primary particle diameter of 4.0 to 10.0,
Styrenic resin foamable particles in which the content of the conductive carbon black is 2 to 25 parts by mass with respect to 100 parts by mass of the styrene resin.   The styrenic resin foamable particles according to claim 1, wherein the conductive carbon black is acetylene black, ketjen black, or a mixture thereof. The styrene resin expandable particle according to claim 1 or 2, wherein the conductive carbon black has a specific surface area of 10 to 3000 m ² / g. A conductive carbon black having 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 agglomerates agglomerated in the styrenic resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The agglomerates are
(I) an average value of the longest diameter of 180 to 500 nm;
(Ii) possess a ratio of the average value of the longest diameter to said average primary particle diameter of 4.0 to 10.0,
Styrenic resin expanded particles in which the content of the conductive carbon black is 2 to 25 parts by mass with respect to 100 parts by mass of the styrene resin.   The styrenic resin expanded particles according to claim 4, wherein the conductive carbon black is acetylene black, ketjen black, or a mixture thereof.   The styrene resin expanded particles according to claim 4 or 5, wherein the styrene resin expanded particles have an average cell diameter of 150 to 350 µm. The styrenic resin expanded particles according to any one of claims 4 to 6, wherein the conductive carbon black has a specific surface area of 10 to 3000 m ² / g. It comprises conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin, and is composed of a plurality of expanded particles fused together.
The primary particles of the conductive carbon black are contained as agglomerates agglomerated in the styrenic resin,
The primary particles have an average primary particle size of 18 to 125 nm,
The agglomerates are
(I) an average value of the longest diameter of 180 to 500 nm;
(Ii) possess a ratio of the average value of the longest diameter to said average primary particle diameter of 4.0 to 10.0,
A styrenic resin foam molded article having a content of the conductive carbon black of 2 to 25 parts by mass with respect to 100 parts by mass of the styrene resin.   The styrenic 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 molded article 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 based on JIS Z8729-2004 “Color Display Method—L * a * b * Color System”, the foamed molded product has the following formula:
31 ≦ ΔE ′ = L ^* + | a ^* | + | b ^* | ≦ 50
(Where ΔE ′ is blackness, L ^* is lightness, a ^* and b ^* are color coordinates)
The styrene resin foam molded article according to any one of claims 8 to 10, which satisfies a relational expression represented by: The styrenic resin foam molding is,
Relative to 100 parts by weight of a styrene resin, wherein the conductive carbon black 2-20 parts by weight,
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 infrared analysis show a ratio A / B of 0.8 to 2.0. 2. A styrene resin foam molded article according to 1.   The styrene resin foam molded article according to claim 12, wherein the absorbance B is 0.5 or more. The styrene resin foam molded article according to any one of claims 8 to 13, wherein the styrene resin foam molded article has a density of 0.01 to 0.04 g / cm ³ . The conductive carbon black, styrene-type resin foamed molded product according to any one of claims 8 to 14 having a specific surface area of 10~3000m 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 styrene resin foam molded article according to any one of claims 8 to 16, further comprising a flame retardant.   An aromatic organic material comprising the styrene resin foam molded article according to claim 8 and comprising the styrene monomer, ethylbenzene, isopropylbenzene, normal propylbenzene, xylene, toluene and benzene in the styrene resin foam molded article. A heat insulating material for a living space whose total content of the compound is less than 2000 ppm. It is a manufacturing method of the styrenic resin expandable particle according to claim 1,
The seed particles are impregnated with a styrene monomer in a dispersion obtained by dispersing seed particles containing conductive carbon black having a volume resistivity of 1.0 × 10 ⁴ Ω · cm or less and a styrene resin in water. A process of
A step of polymerizing the styrenic monomer simultaneously with or after impregnation;
The manufacturing method of the styrene resin foamable particle | grains including the process of impregnating a foaming agent simultaneously with superposition | polymerization or after superposition | polymerization. It is a manufacturing method of the styrenic resin expandable particle according to claim 1,
A step of 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 method of producing styrene resin expandable particles, comprising: extruding the molten resin obtained in the blowing agent injection step into a liquid, cutting the resin, and then solidifying the molten resin.