Expandable styrene resin particles, pre-expanded styrene resin particles, styrene resin foamed molded product, and method for producing expandable styrene resin particles

Abstract

To provide a foamable styrenic resin particle that contains a resin component containing a styrenic resin and other resins and greatly contributes to environmental protection, wherein the styrenic resin particle has a long bead life and high moldability, and a method for producing the same; a preliminarily foamed styrenic resin particle obtained from such a foamable styrenic resin particle; and a foamed styrenic resin molding that is molded from such a foamable styrenic resin particle or such a preliminarily foamed styrenic resin particle.SOLUTION: A foamable styrenic resin particle contains a resin component containing a styrenic resin of 70 mass%-95 mass% and other resins of 5 mass%-30 mass%, and a volatile foamer. Of the styrenic resin, at least 50 mass% is constituted by recycled styrenic resin. Of the other resins, at least 50 mass% is constituted by bioplastic.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to expandable styrene-based resin particles, pre-expanded styrene-based resin particles, a styrene-based resin foamed article, and a method for producing the expandable styrene-based resin particles. [Background technology]

[0002] Since foamed molded articles are lightweight and have excellent heat insulating properties and mechanical strength, they are widely used as heat insulating materials for houses and automobiles, heat retaining materials for building materials, transport packaging materials for fish boxes and food containers, cushioning materials, etc. Among them, in-mold foamed molded articles manufactured using expandable particles (typically, expandable polystyrene-based resin particles or pre-expanded styrene-based resin particles obtained by pre-expanding them) as a raw material are widely used due to the advantage that the desired shape can be easily obtained. Such foamed molded articles are composed of a plurality of expandable particles fused to each other.

[0003] A typical foamed molded product is a styrene-based resin foamed molded product, which has the disadvantages of being brittle to impact and weak against oil and solvents due to the characteristics of the styrene-based resin. To overcome these disadvantages, foamed products made of olefin-based resins such as ethylene-based resins and propylene-based resins and foamed products made of ethylene and styrene polymers have been proposed (for example, Patent Document 1). However, these foamed products require pre-expansion immediately after production of these particles and storage of the produced particles in a pressurized container due to the tendency of the volatile foaming agent impregnated in the raw material foamable olefin-based resin particles or foamable ethylene-styrene polymer particles to dissipate, which results in problems of cumbersome production and storage.

[0004] Also, a foam molded product has been proposed in which a styrene resin and a resin other than a styrene resin are melt-blended in advance in a kneader such as an extruder, and then impregnated with a volatile foaming agent and foamed. Specifically, a technology has been proposed for producing a foam in which pellets of a vinyl aromatic polymer raw material containing a resin other than a styrene resin are heat-melted and impregnated with a foaming agent to foam the pellets (for example, Patent Document 2). However, this technology involves mixing a resin other than a styrene resin to adjust the bubble diameter of the foam, and the content of the resin other than a styrene resin in the resin component is small, so that blending a resin other than a styrene resin does not lead to improvement of the mechanical properties of a styrene resin foam molded product.

[0005] On the other hand, with the growing demand for the construction of a recycling-based society, there is a desire to move away from fossil fuels in the materials field as well as in energy, and the use of bioplastics as an alternative to fossil fuel-derived plastics has attracted attention. Representative examples of bioplastics include biomass plastics made from biomass as a raw material and biodegradable plastics that do not use biomass as a raw material. Biomass is an organic compound photosynthesized from carbon dioxide and water, and by using it, it is a so-called carbon-neutral renewable energy that can be converted back into carbon dioxide and water. Recently, the practical application of biomass plastics made from these biomass raw materials has been rapidly progressing, and attempts have been made to produce various resins from biomass raw materials (for example, Patent Document 3).

[0006] Furthermore, the amount of plastic waste is increasing year by year. Most plastic waste is disposed of by incineration or landfilling, but this has become a major social issue, causing environmental pollution, global warming, and a lack of landfill sites. For this reason, there is a strong social demand for the reuse of plastic waste, and various methods for recycling plastic waste are being considered, such as with the enforcement of the Home Appliance Recycling Law. Among the various recycling methods proposed, material recycling, which reuses plastic waste as plastic components for products, has attracted attention from the perspective of resource circulation and reducing environmental impact. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 48-101457 [Patent Document 2] Special Publication No. 47-26097 [Patent Document 3] JP 2019-182528 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned problems of the prior art, and its main object is to provide expandable styrene-based resin particles with a high environmental contribution, which contain a resin component containing a styrene-based resin and a resin other than a styrene-based resin, and the content ratio of the resin other than the styrene-based resin in the resin component is 5% by mass or more, and which have excellent bead life and moldability, and a method for producing the same. Also, it is an object of the present invention to provide pre-expanded styrene-based resin particles obtained from such expandable styrene-based resin particles. Also, it is an object of the present invention to provide a styrene-based resin foam molded product molded from such expandable styrene-based resin particles or pre-expanded styrene-based resin particles. [Means for solving the problem]

[0009] The expandable styrene-based resin particles according to an embodiment of the present invention are Expandable styrene-based resin particles containing a resin component containing 70% by mass to 95% by mass of a styrene-based resin and 5% by mass to 30% by mass of a resin other than a styrene-based resin, and a volatile blowing agent, 50% by mass or more of the styrene-based resin is recycled styrene-based resin, At least 50 mass % of the resin other than the styrene-based resin is bioplastic.

[0010] In one embodiment, the resin composition containing the resin component and the volatile foaming agent is extruded from an extruder and simultaneously cut in water by an underwater cutting method, and the water pressure in the underwater cutting method is 0.10 MPa to 2.00 MPa, and the discharge rate is 100 kg / hour to 300 kg / hour.

[0011] In one embodiment, the bioplastic is a biomass plastic.

[0012] In one embodiment, the biomass plastic is at least one selected from plant-derived olefin-based resins and plant-derived polyesters.

[0013] The pre-expanded styrene-based resin particles according to an embodiment of the present invention are The pre-expanded styrene-based resin particles are obtained by pre-expanding the expandable styrene-based resin particles, The bulk expansion ratio of the pre-expanded foam is 2 times or more and less than 80 times.

[0014] The styrene-based resin foamed molded article according to the embodiment of the present invention is molded from the above-mentioned expandable styrene-based resin particles.

[0015] The styrene-based resin foamed molded article according to the embodiment of the present invention is molded from the above pre-expanded styrene-based resin particles.

[0016] A method for producing expandable styrene-based resin particles according to an embodiment of the present invention includes the steps of: A method for producing expandable styrene-based resin particles, comprising a resin component containing 70% by mass to 95% by mass of a styrene-based resin and 5% by mass to 30% by mass of a resin other than a styrene-based resin, and a volatile blowing agent, 50% by mass or more of the styrene-based resin is recycled styrene-based resin, 50% by mass or more of the resin other than the styrene-based resin is bioplastic, A resin composition containing the resin component and the volatile foaming agent is extruded from an extruder and simultaneously cut in water, the water pressure in the underwater cutting method being 0.10 MPa to 2.00 MPa and the discharge rate being 100 kg / hour to 300 kg / hour. Effect of the Invention

[0017] According to the present invention, expandable styrene-based resin particles having a high environmental contribution, which contain a resin component containing a styrene-based resin and a resin other than a styrene-based resin, and in which the content of the resin other than a styrene-based resin in the resin component is 5% by mass or more, and which have excellent bead life and moldability, and a manufacturing method thereof can be provided. Also, pre-expanded styrene-based resin particles obtained from such expandable styrene-based resin particles can be provided. Also, a styrene-based resin foam molded article molded from such expandable styrene-based resin particles or pre-expanded styrene-based resin particles can be provided. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of an apparatus suitable for producing expandable styrene-based resin particles according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0020] In this specification, "(meth)acrylic" means acrylic and / or methacrylic, and "(meth)acrylate" means acrylate and / or methacrylate.

[0021] <<A. Expandable styrene resin particles>> The expandable polystyrene resin particles according to an embodiment of the present invention have a particle shape as a whole. The average particle diameter of the expandable polystyrene resin particles is preferably 0.3 mm to 3.0 mm, more preferably 0.3 mm to 2.0 mm. The average particle diameter can be measured in accordance with JIS Z 8815. Specifically, the average particle diameter is a value measured as the particle diameter at the 50% integrated value from the particle size distribution by the sieving test of JIS Z 8815. As the shape of the expandable polystyrene resin particles, any appropriate shape can be adopted as long as the effects of the present invention are not impaired. Specific examples of such shapes include, for example, spherical, substantially spherical, ellipsoidal (oval), cylindrical, substantially cylindrical, and the like.

[0022] The weight average molecular weight of the expandable polystyrene resin particles according to an embodiment of the present invention is preferably 100,000 to 450,000, more preferably 110,000 to 400,000, still more preferably 120,000 to 350,000, and particularly preferably 130,000 to 320,000.

[0023] The expandable polystyrene resin particles according to an embodiment of the present invention are expandable polystyrene resin particles containing a resin component containing 70% by mass to 95% by mass of a styrene resin and 5% by mass to 30% by mass of a resin other than the styrene resin and a volatile foaming agent, wherein 50% by mass or more of the styrene resin is a recycled styrene resin, and 50% by mass or more of the resin other than the styrene resin is a bioplastic.

[0024] ≪A-1. Resin component≫ The resin component contains 70% by mass to 95% by mass of a styrene resin and 5% by mass to 30% by mass of a resin other than the styrene resin.

[0025] <A-1-1. Styrene resin> The styrene resin may be only one kind or two or more kinds.

[0026] The content of the styrene resin in the resin component is typically 70% by mass to 95% by mass, preferably 71% by mass to 94% by mass, more preferably 72% by mass to 93% by mass, particularly preferably 73% by mass to 92% by mass, and most preferably 74% by mass to 91% by mass. If the content of the styrene resin in the resin component is within the above range, the effects of the present invention can be more effectively exhibited. If the content of the styrene resin in the resin component is too low outside the above range, the properties of the styrene resin may not be fully exhibited. If the content of the styrene resin in the resin component is too high outside the above range, the mechanical properties of the expandable styrene resin particles according to the embodiment of the present invention may be poor.

[0027] The styrene resin contains a styrene polymer containing a styrene monomer as a monomer component. The content of the styrene polymer in the styrene resin may be any appropriate content within a range that does not impair the effects of the present invention. Such a content is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more. The upper limit of the content is preferably 100% by mass or less.

[0028] The styrene-based resin may include, for example, a styrene-butadiene copolymer, an ABS resin (acrylonitrile-butadiene-styrene copolymer), or an AS resin (acrylonitrile-styrene copolymer).

[0029] The styrene monomer includes styrene or a styrene derivative. Examples of the styrene derivative include α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene, and bromostyrene. The styrene monomer may be one type or two or more types. The styrene monomer preferably contains at least styrene. The content ratio of styrene to the total amount of the styrene monomer is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0030] The styrene polymer containing a styrene monomer as a monomer component is preferably a styrene polymer containing a styrene monomer as a main component of the monomer component. Such a styrene polymer may be, for example, a copolymer of a styrene monomer and a copolymer component. A representative example of the copolymer component is a vinyl monomer. In this specification, the "main component" means that the content of the component in all components is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0031] Examples of the vinyl monomer include polyfunctional monomers, (meth)acrylic acid ester monomers, maleic acid ester monomers, fumaric acid ester monomers, etc. The vinyl monomer may be one type only, or two or more types may be used.

[0032] Specific examples of the polyfunctional monomer include divinylbenzenes such as o-divinylbenzene, m-divinylbenzene, and p-divinylbenzene; alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate and polyethylene glycol di(meth)acrylate; and the like. By using a polyfunctional monomer, a branched structure can be imparted to the polystyrene resin. The content of the polyfunctional monomer in the total monomer components constituting the styrene resin is preferably 0% by mass to 0.1% by mass, and more preferably 0.005% by mass to 0.05% by mass.

[0033] Specific examples of the (meth)acrylic acid ester monomer include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and hexyl (meth)acrylate. Among these (meth)acrylic acid ester monomers, butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate are preferred, and butyl acrylate is more preferred. By using the (meth)acrylic acid ester monomer, the glass transition temperature (Tg) of the styrene-based resin can be lowered. The content of the acrylic acid ester monomer in the total monomer components constituting the styrene-based resin is preferably 0% by mass to 4.0% by mass, and more preferably 0.1% by mass to 3.0% by mass.

[0034] An example of the maleate monomer is dimethyl maleate.

[0035] Examples of the fumarate monomer include dimethyl fumarate, diethyl fumarate, and ethyl fumarate.

[0036] The styrene resin typically contains 50% by mass or more of recycled styrene resin. The content ratio of the recycled styrene resin in the styrene resin is preferably 60% to 100% by mass, more preferably 70% to 100% by mass, still more preferably 80% to 100% by mass, particularly preferably 90% to 100% by mass, and most preferably substantially 100% by mass. If the content ratio of the recycled styrene resin in the styrene resin is within the above range, expandable styrene resin particles with a high environmental contribution can be provided.

[0037] The recycled styrene resin may be only one type or two or more types.

[0038] As the recycled styrene resin, any appropriate recycled styrene resin can be adopted as long as the effects of the present invention are not impaired. Examples of such recycled styrene resin include recycled products of polystyrene foam (molded products, block molded products, etc.), foam sheets (tray containers, sheet waste materials, etc.), and plastic materials used in household electrical appliances. As the recycled styrene resin, commercially available products such as the product name "Epsrem" manufactured by Sekisui Chemical Co., Ltd. may be adopted.

[0039] If the amount of the recycled styrene resin used as the styrene resin is small, there is a risk that the environmental contribution will be low.

[0040] <A-1-2. Resins other than styrene resin> The resin other than the styrene resin may be only one type or two or more types.

[0041] The content of the resin other than the styrene resin in the resin component is typically 5% by mass to 30% by mass, preferably 6% by mass to 29% by mass, more preferably 7% by mass to 28% by mass, particularly preferably 8% by mass to 27% by mass, and most preferably 9% by mass to 26% by mass. If the content of the resin other than the styrene resin in the resin component is within the above range, the effect of the present invention can be more effectively exhibited. If the content of the resin other than the styrene resin in the resin component is too low outside the above range, the mechanical properties of the expandable styrene resin particles according to the embodiment of the present invention may be deteriorated. If the content of the resin other than the styrene resin in the resin component is too high outside the above range, the retention of the volatile blowing agent of the expandable styrene resin particles may be reduced, and the bead life may be reduced. In particular, as described later, when the resin other than the styrene resin is a biomass plastic, the bead life is highly likely to be reduced.

[0042] The resin other than the styrene-based resin is preferably at least one selected from an olefin-based resin and a polyester. The olefin-based resin may be only one type or may be two or more types. The polyester may be only one type or may be two or more types.

[0043] Examples of olefin-based resins include ethylene-based resins such as polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, etc.), ethylene-α-olefin copolymers (ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, etc.), ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-polar monomer copolymer, and crosslinked bodies of these polymers; propylene-based resins such as propylene homopolymer, propylene-α-olefin copolymer (ethylene-propylene random copolymer, propylene-1-butene copolymer, ethylene-propylene-butene random copolymer, etc.), propylene-vinyl acetate copolymer, and impact copolymers (also called block copolymers) containing up to about 20% ethylene-propylene rubber (EPR) in a propylene homopolymer matrix; and polybutene-1. Among these olefin-based resins, in terms of being able to more effectively exhibit the effects of the present invention, preferred are ethylene-based resins, more preferred are polyethylene, and even more preferred are those having a resin density of 0.900 g / cm 3 ~0.935g / cm 3 and particularly preferably a polyethylene having a resin density of 0.900 g / cm 3 ~0.935g / cm 3 Low density polyethylene (LDPE), resin density is 0.900g / cm 3 ~0.935g / cm 3 It is a linear low density polyethylene (LLDPE).

[0044] Examples of polyesters include polyethylene terephthalate, polycarbonate, and polylactic acid.

[0045] The resin other than the styrene resin typically contains bioplastics in an amount of 50% by mass or more. The content of bioplastics in the resin other than the styrene resin is preferably 60% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, even more preferably 80% by mass to 100% by mass, particularly preferably 90% by mass to 100% by mass, and most preferably substantially 100% by mass. If the content of bioplastics in the resin other than the styrene resin is within the above range, expandable styrene resin particles having a high environmental contribution can be provided.

[0046] The bioplastic may be one type only, or two or more types.

[0047] As the bioplastic, any appropriate bioplastic may be used as long as it does not impair the effects of the present invention. Examples of such bioplastics include biomass plastics and biodegradable plastics, and biomass plastics are preferred in that they can further exert the effects of the present invention.

[0048] The biomass plastic may be, for example, at least one selected from plant-derived olefin-based resins and plant-derived polyesters. The plant-derived olefin-based resin may be only one type, or may be two or more types. The plant-derived polyester may be only one type, or may be two or more types.

[0049] Examples of plant-derived olefin resins include plant-derived polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, etc.), plant-derived ethylene-α-olefin copolymers (ethylene-propylene copolymers, plant-derived ethylene-1-butene copolymers, plant-derived ethylene-1-hexene copolymers, plant-derived ethylene-1-octene copolymers, etc.), plant-derived ethylene-vinyl acetate copolymers, plant-derived ethylene-methyl methacrylate copolymers, plant-derived ethylene-ethyl methacrylate copolymers, plant-derived ethylene-polar monomer copolymers, plant-derived ethylene-α-olefin ... Examples of suitable plant-derived propylene-based resins include plant-derived ethylene-based resins such as ethylene-propylene copolymers and crosslinked products of these polymers; plant-derived propylene homopolymers, plant-derived propylene-α-olefin copolymers (ethylene-propylene random copolymers, propylene-1-butene copolymers, ethylene-propylene-butene random copolymers, etc.), plant-derived propylene-vinyl acetate copolymers, and plant-derived impact copolymers (also called block copolymers) containing up to about 20% ethylene-propylene rubber (EPR) in the matrix of plant-derived propylene homopolymers; and plant-derived polybutene-1. Among these plant-derived olefin-based resins, plant-derived ethylene-based resins are preferred, more preferably plant-derived polyethylene, and even more preferably those having a resin density of 0.900 g / cm. 3 ~0.935g / cm 3 and particularly preferably has a resin density of 0.900 g / cm 3 ~0.935g / cm 3 Low density polyethylene (LDPE) derived from plants, resin density is 0.900g / cm 3 ~0.935g / cm 3 It is a plant-based linear low-density polyethylene (LLDPE).

[0050] An example of a plant-derived polyester is plant-derived polylactic acid.

[0051] <A-2. Volatile foaming agent> The volatile foaming agent may be of only one type, or of two or more types.

[0052] As the volatile blowing agent, any suitable volatile blowing agent can be used within a range that does not impair the effects of the present invention. As the volatile blowing agent, preferably, the boiling point is equal to or lower than the softening point of the styrene-based resin, and is an organic compound that is gaseous or liquid at normal pressure. Specific examples include aliphatic hydrocarbons such as propane, n-butane, isobutane, pentane (n-pentane, isopentane, neopentane), and n-hexane; alicyclic hydrocarbons such as cyclopentane and cyclopentadiene; ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol, and isopropyl alcohol; low-boiling ether compounds such as dimethyl ether, diethyl ether, dipropyl ether, and methyl ethyl ether; halogen-containing hydrocarbons such as trichloromonofluoromethane and dichlorodifluoromethane; and the like. As the volatile blowing agent, inorganic gases such as carbon dioxide, nitrogen, and ammonia may be used. Among these, in terms of being able to more effectively exhibit the effects of the present invention, the volatile blowing agent is preferably at least one selected from n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, and cyclopentadiene, more preferably at least one selected from n-butane, isobutane, n-pentane, and isopentane, even more preferably at least one selected from n-pentane and isopentane, and particularly preferably isopentane. Isopentane has the advantage that it is easily retained in the expandable styrene-based resin particles due to its molecular three-dimensional structure, and is more highly expanded during foaming.

[0053] The content of the volatile foaming agent can be appropriately set depending on the purpose as long as it is a sufficient amount to form pre-expanded styrene-based resin particles and a styrene-based resin foamed molded article. The content of the volatile foaming agent is preferably 2 to 16 parts by mass, more preferably 3 to 8 parts by mass, based on 100 parts by mass of the resin component.

[0054] <A-3. Other ingredients> The expandable styrene-based resin particles according to the embodiment of the present invention may contain a partial ester of higher fatty acid and alcohol in order to prevent the escape of a volatile blowing agent. The partial ester of higher fatty acid and alcohol may be only one type, or may be two or more types. Examples of higher fatty acid include fatty acids having 15 or more carbon atoms, such as palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and behenic acid, and monoglycerides and diglycerides thereof can be used. Examples of partial ester of higher fatty acid and alcohol include preferably stearic acid monoglyceride and stearic acid diglyceride. The content ratio of the partial ester of higher fatty acid and alcohol is preferably 0 to 3 parts by mass, more preferably 0.5 to 3.0 parts by mass, relative to 100 parts by mass of the resin component. As a method for adding the partial ester of higher fatty acid and alcohol to the resin component, for example, a commonly used method such as a dry blend method, a master batch method, and a melt injection method can be adopted.

[0055] The expandable styrene-based resin particles according to the embodiment of the present invention may contain a foaming assistant. The foaming assistant may be one kind or two or more kinds. Examples of the foaming assistant include diisobutyl adipate, toluene, cyclohexane, ethylbenzene, liquid paraffin, and coconut oil.

[0056] The expandable styrene-based resin particles according to the embodiment of the present invention may contain a flame retardant or a flame retardant assistant. The flame retardant or the flame retardant assistant may be one kind or two or more kinds. Examples of the flame retardant include tetrabromocyclooctane, hexabromocyclododecane, hexabromocyclohexane, trisdibromopropyl phosphate, tetrabromobisphenol A, tetrabromobisphenol F, tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tetrabromobisphenol A-diglycidyl ether, 2,2-bis[4'(2'',3''-dibromoalkoxy)-3',5'-dibromophenyl]-propane, and tris(tribromophenoxy)triazine. Examples of the flame retardant aid include cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, and 3,4-dimethyl-3,4-diphenylhexane.

[0057] The expandable styrene-based resin particles according to the embodiment of the present invention may contain a bubble regulator such as talc, calcium carbonate, mica, citric acid, sodium bicarbonate, etc. The bubble regulator may be of only one type or of two or more types.

[0058] The expandable styrene-based resin particles according to the embodiment of the present invention may contain other additives. Examples of such other additives include pigments, radiative heat transfer suppressing components, crosslinking agents, plasticizers, stabilizers, fillers, lubricants, colorants, antistatic agents, spreading agents, weather resistance agents, antiaging agents, antifogging agents, and fragrances. The other additives may be one type only or two or more types.

[0059] <A-4. Surface treatment> The expandable styrene-based resin particles according to the embodiment of the present invention may be subjected to a surface treatment, preferably a surface treatment with at least one selected from silicone oil, an antistatic agent, a fatty acid metal salt, and a fusion accelerator.

[0060] When the expandable styrene resin particles according to the embodiment of the present invention are surface-treated with silicone oil, the amount of silicone oil used relative to 100 parts by mass of the expandable styrene resin particles before surface treatment is preferably 0.001 parts by mass to 0.3 parts by mass, more preferably 0.003 parts by mass to 0.28 parts by mass, even more preferably 0.005 parts by mass to 0.25 parts by mass, particularly preferably 0.008 parts by mass to 0.23 parts by mass, and most preferably 0.01 parts by mass to 0.23 parts by mass. If the amount of silicone oil used is too small outside the above range, for example, when an antistatic agent is used, the affinity with the antistatic agent during pre-foaming may become insufficient, and static electricity may easily occur. If the amount of silicone oil used is too large outside the above range, the surface may melt during molding, resulting in loss of surface properties.

[0061] The silicone oil may be of only one type, or of two or more types.

[0062] As the silicone oil, any suitable silicone oil can be adopted as long as it does not impair the effect of the present invention.In terms of being able to more effectively exhibit the effect of the present invention, the silicone oil can be, for example, straight silicone oil such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, etc., and preferably methylphenylpolysiloxane.

[0063] When the expandable styrene-based resin particles according to the embodiment of the present invention are surface-treated with an antistatic agent, the amount of the antistatic agent used relative to 100 parts by mass of the expandable styrene-based resin particles before surface treatment is preferably 0.001 parts by mass to 0.3 parts by mass, more preferably 0.005 parts by mass to 0.28 parts by mass, even more preferably 0.01 parts by mass to 0.27 parts by mass, particularly preferably 0.015 parts by mass to 0.26 parts by mass, and most preferably 0.02 parts by mass to 0.25 parts by mass. If the amount of the antistatic agent is too small outside the above range, static electricity may be easily generated during pre-expansion. If the amount of the antistatic agent is too large outside the above range, the surface of the pre-expanded styrene-based resin particles or the styrene-based resin foamed molded article may become sticky.

[0064] The antistatic agent may be used alone or in combination of two or more kinds.

[0065] As the antistatic agent, any appropriate antistatic agent may be used as long as it does not impair the effects of the present invention. In terms of being able to more effectively exhibit the effects of the present invention, the antistatic agent may be at least one selected from a nonionic surfactant and a fatty acid glyceride, and preferably a combination of a nonionic surfactant and a fatty acid glyceride.

[0066] The nonionic surfactant may be of only one type, or of two or more types.

[0067] As the nonionic surfactant, any suitable nonionic surfactant may be adopted as long as it does not impair the effects of the present invention. In terms of being able to more effectively express the effects of the present invention, examples of the nonionic surfactant include polyethylene glycol, glycerin, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyhydric alcohol, and 1-amino-2-hydroxy compound. Specific examples of the polyoxyethylene alkyl ether include polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, and polyoxyethylene stearyl ether. Specific examples of the polyoxyethylene alkyl ester include polyoxyethylene laurate, polyoxyethylene palmitate, polyoxyethylene stearate, and polyoxyethylene oleate. Specific examples of the polyhydric alcohol include glycerin and propylene glycol. Specific examples of the 1-amino-2-hydroxy compound include N-hydroxyethyl-N-(2-hydroxyalkyl)amine, N,N-bis(hydroxyethyl)dodecylamine, N,N-bis(hydroxyethyl)tetradecylamine, N,N-bis(hydroxyethyl)hexadecylamine, N,N-bis(hydroxyethyl)octadecylamine, N-hydroxyethyl-N-(2-hydroxytetradecyl)amine, N-hydroxyethyl-N-(2-hydroxyhexadecyl)amine, N-hydroxyethyl-N-(2-hydroxyoctadecyl)amine, N-hydroxypropyl-N Examples of the hydroxyethyl amine include N-(2-hydroxytetradecyl)amine, N-hydroxybutyl-N-(2-hydroxytetradecyl)amine, N-hydroxypentyl-N-(2-hydroxytetradecyl)amine, N-hydroxypentyl-N-(2-hydroxyhexadecyl)amine, N-hydroxypentyl-N-(2-hydroxyoctadecyl)amine, N,N-bis(2-hydroxyethyl)dodecylamine, N,N-bis(2-hydroxyethyl)tetradecylamine, N,N-bis(2-hydroxyethyl)hexadecylamine, N,N-bis(2-hydroxyethyl)octadecylamine, and salts thereof.As the nonionic surfactant, polyethylene glycol is preferred in that the effects of the present invention can be more effectively exhibited.

[0068] When a nonionic surfactant is used as at least a part of the antistatic agent, the amount of the nonionic surfactant used relative to 100 parts by mass of the expandable styrene-based resin particles before surface treatment is preferably 0.001 parts by mass to 0.3 parts by mass, more preferably 0.005 parts by mass to 0.28 parts by mass, even more preferably 0.01 parts by mass to 0.27 parts by mass, particularly preferably 0.015 parts by mass to 0.26 parts by mass, and most preferably 0.02 parts by mass to 0.25 parts by mass. If the amount of the nonionic surfactant is too small outside the above range, static electricity may be easily generated during pre-expansion. If the amount of the nonionic surfactant is too large outside the above range, the surface of the pre-expanded styrene-based resin particles or the styrene-based resin foamed molded article may become sticky.

[0069] The fatty acid glyceride may be of only one type, or of two or more types.

[0070] As the fatty acid glyceride, any suitable fatty acid glyceride can be adopted as long as it does not impair the effects of the present invention.Specific examples of the fatty acid glyceride that can further demonstrate the effects of the present invention include stearic acid monoglyceride and linoleic acid monoglyceride.As the fatty acid glyceride, stearic acid monoglyceride is preferred in terms of further demonstrating the effects of the present invention.

[0071] When fatty acid glyceride is used as at least a part of the antistatic agent, the amount of the fatty acid glyceride relative to 100 parts by mass of the expandable styrene resin particles before surface treatment is preferably 0.001 parts by mass to 0.3 parts by mass, more preferably 0.005 parts by mass to 0.28 parts by mass, even more preferably 0.01 parts by mass to 0.27 parts by mass, particularly preferably 0.015 parts by mass to 0.26 parts by mass, and most preferably 0.02 parts by mass to 0.25 parts by mass. If the amount of fatty acid glyceride is too small outside the above range, static electricity may be easily generated during pre-expansion. If the amount of fatty acid glyceride is too large outside the above range, the surface of the pre-expanded styrene resin particles or the styrene resin foamed molded article may become sticky.

[0072] When the expandable styrene resin particles according to the embodiment of the present invention are surface-treated with a fatty acid metal salt, the amount of fatty acid metal salt used relative to 100 parts by mass of the expandable styrene resin particles before surface treatment is preferably 0.005 parts by mass to 0.5 parts by mass, more preferably 0.007 parts by mass to 0.45 parts by mass, even more preferably 0.01 parts by mass to 0.4 parts by mass, particularly preferably 0.015 parts by mass to 0.35 parts by mass, and most preferably 0.02 parts by mass to 0.3 parts by mass. If the amount of fatty acid metal salt is too small outside the above range, blocking may occur frequently during pre-expansion, and a good styrene resin foamed molded article may not be obtained. If the amount of fatty acid metal salt is too large outside the above range, a large amount of metal salt is present during pre-expansion, which makes it easy to be charged, which makes it easy to generate static electricity, and the fusion of the molded article may be poor.

[0073] The fatty acid metal salt may be of only one type or of two or more types.

[0074] As the fatty acid metal salt, any suitable fatty acid metal salt may be adopted as long as it does not impair the effects of the present invention. In terms of being able to more effectively express the effects of the present invention, examples of the fatty acid metal salt include metal stearates and metal laurates. Specific examples of the metal stearates include magnesium stearate, calcium stearate, zinc stearate, barium stearate, aluminum stearate, and lithium stearate. Specific examples of the metal laurate include zinc laurate and barium laurate. In terms of being able to more effectively express the effects of the present invention, magnesium stearate and zinc stearate are preferred as fatty acid metal salts.

[0075] When the surface treatment with a fusion accelerator is performed on the expandable styrene resin particles according to the embodiment of the present invention, the amount of the fusion accelerator used relative to 100 parts by mass of the expandable styrene resin particles before the surface treatment is preferably 0.01 parts by mass to 0.8 parts by mass, more preferably 0.01 parts by mass to 0.7 parts by mass, even more preferably 0.01 parts by mass to 0.6 parts by mass, particularly preferably 0.01 parts by mass to 0.55 parts by mass, and most preferably 0.013 parts by mass to 0.5 parts by mass. If the amount of the fusion accelerator is too small outside the above range, the fusion property may decrease during molding, and a good styrene resin foam molded article may not be obtained. If the amount of the fusion accelerator is too large outside the above range, blocking may occur during pre-expansion.

[0076] The fusion promoter may be of only one type, or of two or more types.

[0077] As the fusion promoter, any suitable fusion promoter may be adopted as long as it does not impair the effects of the present invention. In terms of being able to further express the effects of the present invention, examples of the fusion promoter include fatty acid triglycerides, fatty acid diglycerides, fatty acid monoglycerides, and vegetable oils. Specific examples of fatty acid triglycerides include lauric acid triglyceride, stearic acid triglyceride, linoleic acid triglyceride, and hydroxystearic acid triglyceride. Specific examples of fatty acid diglycerides include lauric acid diglyceride, stearic acid diglyceride, and linoleic acid diglyceride. Specific examples of fatty acid monoglycerides include lauric acid monoglyceride. Specific examples of vegetable oils include hydrogenated castor oil. In terms of being able to further express the effects of the present invention, hydroxystearic acid triglyceride is preferred as the fusion promoter.

[0078] <A-5. Manufacturing method of expandable styrene-based resin particles> The expandable styrene-based resin particles according to the embodiment of the present invention can be produced by any suitable method as long as the effects of the present invention are not impaired. In terms of being able to more effectively exhibit the effects of the present invention, the expandable styrene-based resin particles are preferably produced by an underwater cutting method in which a resin composition containing a resin component and a volatile foaming agent is extruded from an extruder and cut in water at the same time.

[0079] More specifically, in a method for producing expandable styrene-based resin particles according to an embodiment of the present invention by the underwater cutting method, a resin component containing 70% by mass to 95% by mass of a styrene-based resin and 5% by mass to 30% by mass of a resin other than a styrene-based resin is supplied to an extruder, heated and melted, a volatile foaming agent is injected midway through the extruder, and the resulting resin composition is extruded into water through a multi-hole die, and simultaneously with extrusion, cut in water to form resin particles.

[0080] When cutting in water simultaneously with extrusion, the temperature of the water is preferably 15°C to 60°C, more preferably 20°C to 40°C. If the water temperature is lower than 15°C, the die surface is cooled more intensely, the holes in the die are more likely to be blocked, and the pressure inside the die increases, which may make extrusion difficult. If the water temperature is higher than 60°C, it may be difficult to suppress foaming, and if the water temperature exceeds 80°C, the resin particles obtained by cutting may be more likely to coalesce.

[0081] The temperature of the water is preferably 100° C. to 200° C. lower than the temperature of the resin composition at the time of flowing into the die. If the temperature difference between the water temperature and the resin composition temperature is less than 100° C., the resulting resin particles may not be sufficiently cooled, making it difficult to suppress foaming, and if the temperature difference between the water temperature and the resin composition temperature exceeds 200° C., the resulting resin particles may deform due to the temperature difference between the surface and the interior of the resin particles, and may not become perfectly spherical.

[0082] In the underwater cutting method, the water pressure is adjusted to 0.10 MPa to 2.00 MPa, and the discharge rate is adjusted to 100 kg / hour to 300 kg / hour. By adjusting the water pressure and discharge rate in the underwater cutting method in this way, the effects of the present invention can be achieved. In the underwater cutting method, the water pressure corresponds to the resistance force when the resin is extruded from the die into the water, and the discharge rate corresponds to the force in the extrusion direction when the resin composition is extruded from the die into the water. Therefore, in the underwater cutting method, unless the water pressure and the discharge rate are appropriately adjusted, the expandable styrene-based resin particles cannot be produced well. In particular, when a recycled styrene-based resin is used as a resin component, the molecular weight tends to decrease and the fluidity increases due to the heat history that the recycled styrene-based resin received during the regeneration, and the fluidity and viscoelasticity change because the additive derived from the recycled raw material contains an arbitrary amount, and therefore, strict adjustment of the water pressure and the discharge rate in the underwater cutting method is required.

[0083] In order to more effectively exert the effects of the present invention, the water pressure in the underwater cutting method is preferably 0.12 MPa to 1.90 MPa, more preferably 0.13 MPa to 1.85 MPa, still more preferably 0.15 MPa to 1.80 MPa, and particularly preferably 0.20 MPa to 1.60 MPa.

[0084] In order to more effectively exert the effects of the present invention, the discharge rate in the underwater cutting method is preferably 110 kg / hour to 280 kg / hour, more preferably 120 kg / hour to 270 kg / hour, even more preferably 130 kg / hour to 260 kg / hour, and particularly preferably 150 kg / hour to 250 kg / hour.

[0085] In order to more effectively exert the effects of the present invention, the aperture ratio in the underwater cutting method is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, particularly preferably 65% ​​or more, and most preferably 70% or more. Here, the aperture ratio is the aperture ratio of small holes on the die surface during extrusion, and is calculated by the calculation formula described later.

[0086] An example of an apparatus suitable for producing expandable styrene-based resin particles according to an embodiment of the present invention by the underwater cutting method is shown in Fig. 1. This production apparatus is configured to include an extruder 1 having a raw material supply hopper 11 for feeding a resin component on the upstream side in the resin flow direction (from left to right in Fig. 1), a volatile foaming agent supply port 12 having a high-pressure pump 13 on the downstream side of the raw material supply hopper 11 in the resin flow direction, and a multi-hole die 2 at the end of the resin flow direction, a cutting chamber 3 that is provided so as to cover the outlet of the multi-hole die 2 and has a cutter 31 arranged therein so as to be rotatable and is configured to circulate water therein, a water tank 6 and a water pump 4 for supplying water to the cutting chamber 3, a dehydrator 5 that introduces the expandable styrene-based resin particles cut in the cutting chamber 3 together with water and separates the water from the expandable styrene-based resin particles, and a container 7 that stores the expandable styrene-based resin particles separated by the dehydrator 5.

[0087] As the extruder 1, a known extruder used in extrusion molding of a resin composition can be used. Examples of such extruders include a single-screw extruder, a twin-screw extruder, and a tandem extruder. The extruder 1 feeds a resin component from a raw material supply hopper 11, heats and kneads the resin component in the extruder 1, and transfers the molten kneaded product downstream in the resin flow direction. When the molten kneaded product reaches a volatile foaming agent supply port 12, a volatile foaming agent pumped by a high-pressure pump 13 is mixed into the molten kneaded product. The resulting resin composition is then extruded from a multi-hole die 2 into a cutting chamber 3, comes into contact with water, and is cut by a cutter 31 in water. The cut resin composition becomes spherical particles of approximately uniform particle size, and is transported from the cutting chamber 3 to a dehydrating dryer 5 by a circulating water flow. The expandable styrene-based resin particles obtained by separating the water from the dehydrating dryer 5 and drying the resin component are stored in a container 7, while the water is sent to a water tank 6.

[0088] <<B. Pre-expanded styrene resin particles>> The pre-expanded styrene-based resin particles are prepared by pre-expanding expandable styrene-based resin particles.

[0089] The pre-expanded styrene-based resin particles have an average cell diameter of preferably 0.04 mm to 1.00 mm, more preferably 0.04 mm to 0.90 mm, even more preferably 0.04 mm to 0.80 mm, particularly preferably 0.04 mm to 0.70 mm, and most preferably 0.04 mm to 0.60 mm. If the average cell diameter of the pre-expanded styrene-based resin particles is within the above range, it is possible to provide pre-expanded styrene-based resin particles which can better prevent blocking during expansion and molding, and which can further suppress electrostatic charge during expansion and molding while exhibiting better fusibility and surface properties, thereby enabling the molding of a styrene-based resin foamed molded article with less static electricity.

[0090] That is, the pre-expanded styrene-based resin particles according to the embodiment of the present invention are obtained by pre-expanding the expandable styrene-based resin particles described in the above item A. The pre-expanding includes expanding the expandable styrene-based resin particles to a desired bulk expansion ratio (bulk density) using water vapor or the like. The bulk expansion ratio of the pre-expanded styrene-based resin particles is preferably 2 times or more and less than 80 times, more preferably 5 times to 78 times, even more preferably 10 times to 75 times, and particularly preferably 15 times to 65 times. The bulk density is the reciprocal of the bulk expansion ratio. The bulk expansion ratio and bulk density are determined, for example, as follows. By having the bulk expansion ratio of the pre-expanded styrene-based resin particles within the above range, blocking during expansion and molding can be further prevented, and further, the pre-expanded styrene-based resin particles can be provided that exhibit better fusion properties and surface properties while further suppressing electrostatic charge during expansion and molding, and can mold a styrene-based resin foam molded article with less static electricity.

[0091] A measurement sample of W (g) of expandable styrene resin particles is collected. This measurement sample is allowed to fall naturally into a measuring cylinder, and the volume of the measurement sample that fell into the measuring cylinder, V (cm 3 ) is measured using an apparent density measuring device conforming to JIS K 6911. From the mass and volume of the measurement sample, the bulk expansion ratio and bulk density can be calculated according to the following formula. Bulk foaming ratio (times = cm 3 / g) = volume of measurement sample (V) / mass of measurement sample (W) Bulk density (g / cm 3 ) = mass of measurement sample (W) / volume of measurement sample (V)

[0092] In one representative embodiment, the pre-expanded styrene-based resin particles can be used for forming a styrene-based resin foamed molded article. In another embodiment, the pre-expanded styrene-based resin particles can be used as they are as a buffer material, a heat insulating material, etc. When the pre-expanded styrene-based resin particles are used as they are, the pre-expanded styrene-based resin particles can be preferably used as a packed body in which a large number of the pre-expanded styrene-based resin particles are filled in a bag.

[0093] <<C. Styrene-based resin foam molding>> A styrene-based resin foamed molded article according to one embodiment of the present invention is a styrene-based resin foamed molded article formed from expandable styrene-based resin particles. A styrene-based resin foamed molded article according to another embodiment of the present invention is a styrene-based resin foamed molded article formed from pre-expanded styrene-based resin particles obtained by pre-expanding expandable styrene-based resin particles.

[0094] The styrene-based resin foamed molded article typically contains expanded styrene-based resin particles (hereinafter sometimes simply referred to as "expanded particles") obtained by further expanding pre-expanded styrene-based resin particles.

[0095] A styrene-based resin foamed molded article is typically composed of a plurality of foamed particles fused to one another.

[0096] The styrene-based resin foam molded article can be typically produced by charging pre-expanded styrene-based resin particles into a mold having a predetermined shape according to the purpose and performing in-mold foam molding. More specifically, the in-mold foam molding includes (i) filling the pre-expanded styrene-based resin particles into a closed mold having a large number of small holes, (ii) heating and foaming the pre-expanded styrene-based resin particles with a heat medium (e.g., pressurized steam, etc.) to obtain foamed particles, and (iii) filling the voids between the foamed particles by the heating and foaming, and fusing the foamed particles to each other to integrate them. The density of the styrene-based resin foam molded article can be appropriately set according to the purpose. The density of the styrene-based resin foam molded article can be adjusted, for example, by previously adjusting the bulk expansion ratio of the pre-expanded styrene-based resin particles to be filled in the mold, or by adjusting the amount of pre-expanded styrene-based resin particles to be filled in the mold.

[0097] The heat-foaming temperature (substantially the temperature of the heat transfer medium) is preferably 90°C to 150°C, more preferably 110°C to 130°C. The heat-foaming time is preferably 5 seconds to 50 seconds, more preferably 10 seconds to 50 seconds. The molding vapor pressure of the heat-foaming (gauge pressure of the heat transfer medium blowing in) is preferably 0.04 MPa to 0.1 MPa, more preferably 0.06 MPa to 0.08 MPa. If the heat-foaming is performed under such conditions, the expanded particles can be well fused to each other.

[0098] If necessary, the pre-expanded styrene resin particles may be aged before molding into a styrene resin foamed molded article. The aging temperature of the pre-expanded styrene resin particles is preferably 20°C to 60°C. If the aging temperature is too low, an excessively long aging time may be required. If the aging temperature is too high, the blowing agent in the pre-expanded styrene resin particles may dissipate, resulting in a decrease in moldability.

[0099] The bulk expansion ratio of the expanded beads in the styrene-based resin expansion molded product is preferably 2 times or more and less than 80 times, more preferably 5 times to 78 times, further preferably 10 times to 75 times, and particularly preferably 15 times to 65 times. EXAMPLES

[0100] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring and evaluating each property are as follows.

[0101] <Beads Life> After the production of the expandable styrene resin particles, they were left for 30 days under normal pressure (1 atm) and temperature conditions of 18°C, and the expandability was evaluated immediately after production and after 30 days. The expandability evaluation method involved placing the expandable styrene resin particles in a box-shaped container, blowing steam into it, and gradually heating at a pressure of 0.05 MPa to 0.10 MPa (gauge pressure) and at 90°C to 100°C for 1 minute to 10 minutes, and checking the difference in the maximum expansion ratio. Bead life(%) = [((maximum expansion ratio after 30 days) - (maximum expansion ratio immediately after production)) / (maximum expansion ratio immediately after production)] x 100 The evaluation was based on the following criteria. 〇: -60% or more and 0% or less ×: Less than -60%

[0102] <Coalescence particle rate> Approximately 1 g of randomly selected expandable styrene resin particles was precisely weighed on an electronic balance to determine the mass (W1). From these, particles in which two or more particles were coalesced were selected and similarly precisely weighed on an electronic balance to determine the mass (W2), and the coalesced particle ratio was calculated using the following formula. Coalescing particle rate (%)=(W2 / W1)×100 The evaluation was based on the following criteria. ○: Less than 0.5% △: 0.5 or more and less than 1.0% ×: 1.0% or more

[0103] <Open area ratio> After one hour had elapsed from the start of production of the expandable styrene-based resin particles, the resin discharge surface of the die was examined, and the opening rate of the small holes was calculated as follows. Perforation rate (perforation rate of small holes on the die surface during extrusion) (%) = (number of holes / total number of small holes on the die) x 100 Output (kg / hour) = Total mass of all expandable styrene resin particles cut out by the cutter per hour = Number of holes x Number of cut pieces x Mass of one grain = Number of holes x Number of cutter blades x Number of cutter rotations x Mass of one grain Therefore, the number of holes is Number of apertures = output rate (kg / hour) / [number of cutter blades x cutter rotation speed (rph) x mass of one pellet (kg / particle)], so the aperture rate can be calculated using the following formula. Open area ratio (E) (%) = (number of open holes / total number of small holes) x 100 =[[Q / (N×R×60×(M / 100) / 1000)] / H]×100 (In the formula, Q is the discharge rate (kg / hour), N is the number of cutter blades, R is the cutter rotation speed (rpm), M is the mass of 100 particles (g) (100 particles randomly selected from expandable styrene resin particles and weighed on an electronic balance with a minimum scale of 0.0001g), and H is the total number of small holes in the die.) The pore opening rate was evaluated according to the following criteria. 〇: 70% or more △: 50% or more but less than 70% ×: Less than 50%

[0104] <Moldability> The elongation of the surface of the molded body and the fusion rate between the foam particles when the molded body was broken were comprehensively evaluated. The evaluation of the elongation of the surface of the molded body was performed by visually evaluating the appearance of the obtained foamed molded body. Specifically, the state of the boundary part where the foam particles on the surface of the foamed molded body were joined was visually evaluated. The fusion rate between the foam particles when the molded body was broken was evaluated by breaking the obtained plate-shaped foamed molded body by impact, counting the total number of foam particles (A) on the fracture surface and the number of particles broken within the particles (B), and calculating the fusion rate (%) by the following formula. Fusion rate (%) = {(B) / (A)} x 100 The evaluation was based on the following criteria. ◯: Appearance is smooth and the fusion rate is 70% or more. △: Most of the appearance is smooth, but there are some unevenness at the boundaries, and the fusion rate is 60% or more and less than 70%. ×: The boundary portion of the appearance is uneven, the smoothness is poor, and the fusion rate is less than 60%.

[0105] <Environmental contribution> The expandable styrene resin particles were evaluated as follows based on the content ratio of recycled styrene resin and bioplastic in the resin component that is the raw material of the expandable styrene resin particles. 〇: The total amount of recycled styrene resin and bioplastic is 75% or more by mass, and bioplastic is 5% or more by mass. ×: The total amount of recycled styrene resin and bioplastic is less than 75% by mass and / or bioplastic is less than 5% by mass

[0106] <Criteria for overall evaluation> Particularly good (◎): Coalescence particle rate, pore rate, bead life, moldability, and environmental contribution are all 〇. Good (〇): One or more of the following items are △: rate of coalesced particles, pore rate, bead life, moldability, and environmental contribution. Poor (×): There is at least one × in the following items: rate of coalesced particles, rate of pores, bead life, moldability, and environmental contribution.

[0107] Example 1 A mixed resin of 90 parts by mass of recycled styrene resin (recycled polystyrene foam pellets) and 10 parts by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant content is 95% according to ASTM D6866), and 0.5 parts by mass of talc were fed to a φ90 mm short-screw extruder, heated and melted, and then 5 parts by mass of pentane (normal / iso = 80 / 20) was pressed in as a volatile foaming agent for 100 parts by mass of the mixed resin, and melt-mixed. Next, the resin composition melted in the extruder was kneaded and cooled, and extruded into a cutting chamber filled with water at 30 ° C. through a multi-hole die with extrusion holes of φ0.6 mm × 200 at a temperature of the resin composition of 170 ° C., immediately cut in water, and dehydrated through a stretching dehydrator to obtain expandable styrene resin particles (1) with a diameter of about 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=80% The obtained expandable styrene-based resin particles (1): 5,000 g, polyethylene glycol: 1.5 g, zinc stearate: 5.0 g, fatty acid triglyceride: 10.0 g, and fatty acid monoglyceride: 3.0 g were placed in a tumbler mixer and stirred for 15 minutes to surface-treat the expandable styrene-based resin particles (1). The surface-treated expandable styrene resin particles (1) were stored in a refrigerator at 15°C for one day, and then 500 g were placed in a cylindrical batch type expansion machine with a capacity of 25 liters and heated with steam to obtain pre-expanded styrene resin particles (1). The bulk density of the pre-expanded styrene resin particles (1) was 0.020 g / cm. 3The bulk ratio was 50 times. After leaving the pre-expanded styrene resin particles (1) for 24 hours under room temperature atmosphere, a molding machine having a mold with a cavity size of 300 mm in height, 400 mm in width, and 30 mm in depth was used to fill the cavity of the mold with the pre-expanded styrene resin particles (1), which was then heated for 30 seconds at a vapor pressure of 0.065 MPa (gauge pressure), and then cooled until the pressure inside the mold became 0.03 MPa. The mold was then released from the mold, and a plate-shaped styrene resin foamed molded product (1) corresponding to the mold was obtained. The density of the styrene resin foamed molded product (1) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (1) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (1) was evaluated. The results are shown in Table 1.

[0108] Example 2 The procedure was carried out in the same manner as in Example 1, except that a mixed resin of 95 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 5 parts by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used as the mixed resin, and expandable styrene-based resin particles (2) with a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=72% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (2) and pre-expanded styrene-based resin particles (2). The bulk density of the pre-expanded styrene-based resin particles (2) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (2). The density of the styrene-based resin foam molded product (2) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foamed molded article (2) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (2) was evaluated. The results are shown in Table 1.

[0109] Example 3 The procedure was carried out in the same manner as in Example 1, except that a mixed resin of 72 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 28 parts by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used as the mixed resin, and expandable styrene-based resin particles (3) with a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=78% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (3) and pre-expanded styrene-based resin particles (3). The bulk density of the pre-expanded styrene-based resin particles (3) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (3). The density of the styrene-based resin foam molded product (3) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foamed molded product (3) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (3) was evaluated. The results are shown in Table 1.

[0110] Example 4 The procedure was carried out in the same manner as in Example 1, except that a mixed resin of 70 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 30 parts by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used as the mixed resin, and expandable styrene-based resin particles (4) with a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=77% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (4) and pre-expanded styrene-based resin particles (4). The bulk density of the pre-expanded styrene-based resin particles (4) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (4). The density of the styrene-based resin foam molded product (4) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (4) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (4) was evaluated. The results are shown in Table 1.

[0111] Comparative Example 1 The procedure was repeated as in Example 1, except that a mixed resin of 65 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 35 parts by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used as the mixed resin, and expandable styrene-based resin particles (C1) with a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=77% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C1) and pre-expanded styrene-based resin particles (C1). The bulk density of the pre-expanded styrene-based resin particles (C1) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (C1). The density of the styrene-based resin foam molded product (C1) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C1) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C1) was evaluated. The results are shown in Table 1.

[0112] Comparative Example 2 The procedure was repeated as in Example 1, except that a mixed resin of 99 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 1 part by mass of bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used, to obtain expandable styrene-based resin particles (C2) with a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=88% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C2) and pre-expanded styrene-based resin particles (C2). The bulk density of the pre-expanded styrene-based resin particles (C2) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foamed molded product (C2). The density of the styrene-based resin foamed molded product (C2) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C2) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (C2) was evaluated. The results are shown in Table 1.

[0113] Comparative Example 3 The procedure was repeated as in Example 1, except that a mixed resin of 65 parts by mass of a general-purpose styrene-based resin (manufactured by Toyo Styrene Co., Ltd., product name "HRM10N") and 35 parts by mass of a bioplastic polyethylene (manufactured by Braskem Co., Ltd., product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used, to obtain expandable styrene-based resin particles (C3) with a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=75% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C3) and pre-expanded styrene-based resin particles (C3). The bulk density of the pre-expanded styrene-based resin particles (C3) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (C3) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (C3) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C3) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C3) was evaluated. The results are shown in Table 1.

[0114] Comparative Example 4 The procedure was carried out in the same manner as in Example 1, except that a mixed resin of 99 parts by mass of a general-purpose styrene-based resin (manufactured by Toyo Styrene, product name "HRM10N") and 1 part by mass of a bioplastic polyethylene (manufactured by Braskem, product name "SBF0323HC", plant-based content 95% in accordance with ASTM D6866) was used, to obtain expandable styrene-based resin particles (C4) having a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=87% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C4) and pre-expanded styrene-based resin particles (C4). The bulk density of the pre-expanded styrene-based resin particles (C4) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (C4). The density of the styrene-based resin foam molded product (C4) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C4) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C4) was evaluated. The results are shown in Table 1.

[0115] [Table 1]

[0116] Example 5 The same procedure as in Example 1 was repeated, except that a mixed resin of 90 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 10 parts by mass of bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (5) having a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=82% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (5) and pre-expanded styrene-based resin particles (5). The bulk density of the pre-expanded styrene-based resin particles (5) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (5). The density of the styrene-based resin foam molded product (5) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (5) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (5) was evaluated. The results are shown in Table 2.

[0117] Example 6 The same procedure as in Example 5 was repeated, except that a mixed resin of 95 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 5 parts by mass of bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (6) having a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=84% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (6) and pre-expanded styrene-based resin particles (6). The bulk density of the pre-expanded styrene-based resin particles (6) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (6). The density of the styrene-based resin foam molded product (6) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (6) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (6) was evaluated. The results are shown in Table 2.

[0118] Example 7 The same procedure as in Example 5 was repeated, except that a mixed resin of 72 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 28 parts by mass of bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (7) having a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=79% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (7) and pre-expanded styrene-based resin particles (7). The bulk density of the pre-expanded styrene-based resin particles (7) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (7). The density of the styrene-based resin foam molded product (7) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (7) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (7) was evaluated. The results are shown in Table 2.

[0119] Example 8 The same procedure as in Example 5 was repeated, except that a mixed resin of 70 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 30 parts by mass of bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (8) having a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=77% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (8) and pre-expanded styrene-based resin particles (8). The bulk density of the pre-expanded styrene-based resin particles (8) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (8). The density of the styrene-based resin foam molded product (8) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (8) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (8) was evaluated. The results are shown in Table 2.

[0120] Comparative Example 5 The same procedure as in Example 1 was repeated, except that a mixed resin of 65 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 35 parts by mass of bioplastic polylactic acid (manufactured by NatureWorks, product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (C5) with a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=77% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C5) and pre-expanded styrene-based resin particles (C5). The bulk density of the pre-expanded styrene-based resin particles (C5) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (C5). The density of the styrene-based resin foam molded product (C5) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C5) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C5) was evaluated. The results are shown in Table 2.

[0121] Comparative Example 6 The same procedure as in Example 1 was repeated, except that a mixed resin of 99 parts by mass of recycled styrene-based resin (recycled polystyrene foam pellets) and 1 part by mass of bioplastic polylactic acid (manufactured by NatureWorks, product name "Ingeo4032D") was used as the mixed resin, to obtain expandable styrene-based resin particles (C6) with a diameter of approximately 1.2 mm. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=87% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C6) and pre-expanded styrene-based resin particles (C6). The bulk density of the pre-expanded styrene-based resin particles (C6) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (C6). The density of the styrene-based resin foam molded product (C6) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C6) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C6) was evaluated. The results are shown in Table 2.

[0122] Comparative Example 7 The procedure was repeated as in Example 1, except that a mixed resin of 65 parts by mass of a general-purpose styrene-based resin (manufactured by Toyo Styrene Co., Ltd., product name "HRM10N") and 35 parts by mass of a bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, and expandable styrene-based resin particles (C7) with a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=74% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C7) and pre-expanded styrene-based resin particles (C7). The bulk density of the pre-expanded styrene-based resin particles (C7) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (C7). The density of the styrene-based resin foam molded product (C7) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C7) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C7) was evaluated. The results are shown in Table 2.

[0123] Comparative Example 8 The procedure was repeated as in Example 1, except that a mixed resin of 99 parts by mass of a general-purpose styrene-based resin (manufactured by Toyo Styrene Co., Ltd., product name "HRM10N") and 1 part by mass of a bioplastic polylactic acid (manufactured by NatureWorks, Inc., product name "Ingeo4032D") was used as the mixed resin, and expandable styrene-based resin particles (C8) having a diameter of approximately 1.2 mm were obtained. The extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=180kg / hour Open area rate=87% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (C8) and pre-expanded styrene-based resin particles (C8). The bulk density of the pre-expanded styrene-based resin particles (C8) was 0.020 g / cm 3The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (C8) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (C8) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (C8) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (C8) was evaluated. The results are shown in Table 2.

[0124] [Table 2]

[0125] Example 9 The same procedure as in Example 1 was carried out, except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (9). Water pressure = 0.30MPa Discharge amount=100kg / hour Open area rate=65% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (9) and pre-expanded styrene-based resin particles (9). The bulk density of the pre-expanded styrene-based resin particles (9) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (9). The density of the styrene-based resin foam molded product (9) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (9) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (9) was evaluated. The results are shown in Table 3.

[0126] Example 10 The same procedure as in Example 1 was carried out, except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (10). Water pressure = 0.30MPa Discharge amount=150kg / hour Open area rate=75% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (10) and pre-expanded styrene-based resin particles (10). The bulk density of the pre-expanded styrene-based resin particles (10) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (10). The density of the styrene-based resin foam molded product (10) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (10) was dried in a drying chamber at 30°C. The resulting styrene resin foam molded article (10) was evaluated. The results are shown in Table 3.

[0127] Example 11 The same procedure as in Example 1 was carried out, except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (11). Water pressure = 0.30MPa Discharge amount=200kg / hour Open area rate=85% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (11) and pre-expanded styrene-based resin particles (11). The bulk density of the pre-expanded styrene-based resin particles (11) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (11). The density of the styrene-based resin foam molded product (11) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (11) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (11) was evaluated. The results are shown in Table 3.

[0128] Example 12 Expandable styrene-based resin particles (12) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=250kg / hour Open area rate=85% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (12) and pre-expanded styrene-based resin particles (12). The bulk density of the pre-expanded styrene-based resin particles (12) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (12). The density of the styrene-based resin foam molded product (12) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (12) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (12) was evaluated. The results are shown in Table 3.

[0129] Example 13 The same procedure as in Example 1 was carried out, except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (13). Water pressure = 0.30MPa Discharge amount=300kg / hour Open area rate=85% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (13) and pre-expanded styrene-based resin particles (13). The bulk density of the pre-expanded styrene-based resin particles (13) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (13). The density of the styrene-based resin foam molded product (13) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (13) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (13) was evaluated. The results are shown in Table 3.

[0130] Example 14 Expandable styrene-based resin particles (14) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 0.10MPa Discharge amount=200kg / hour Open area rate=88% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (14) and pre-expanded styrene-based resin particles (14). The bulk density of the pre-expanded styrene-based resin particles (14) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (14). The density of the styrene-based resin foam molded product (14) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (14) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (14) was evaluated. The results are shown in Table 3.

[0131] Example 15 Expandable styrene-based resin particles (15) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 0.20MPa Discharge amount=200kg / hour Open area rate=86% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (15) and pre-expanded styrene-based resin particles (15). The bulk density of the pre-expanded styrene-based resin particles (15) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (15). The density of the styrene-based resin foam molded product (15) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (15) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (15) was evaluated. The results are shown in Table 3.

[0132] Example 16 Expandable styrene-based resin particles (16) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 0.50MPa Discharge amount=200kg / hour Open area rate=74% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (16) and pre-expanded styrene-based resin particles (16). The bulk density of the pre-expanded styrene-based resin particles (16) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (16). The density of the styrene-based resin foam molded product (16) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (16) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (16) was evaluated. The results are shown in Table 3.

[0133] Example 17 Expandable styrene-based resin particles (17) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 0.70MPa Discharge amount=200kg / hour Open area rate=72% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (17) and pre-expanded styrene-based resin particles (17). The bulk density of the pre-expanded styrene-based resin particles (17) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (17). The density of the styrene-based resin foam molded product (17) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (17) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (17) was evaluated. The results are shown in Table 3.

[0134] Example 18 Expandable styrene-based resin particles (18) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 1.00MPa Discharge amount=200kg / hour Open area rate=70% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (18) and pre-expanded styrene-based resin particles (18). The bulk density of the pre-expanded styrene-based resin particles (18) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (18). The density of the styrene-based resin foam molded product (18) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (18) was dried in a drying chamber at 30°C. The resulting styrene resin foam molded article (18) was evaluated. The results are shown in Table 3.

[0135] Example 19 Expandable styrene-based resin particles (19) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 1.50MPa Discharge amount=200kg / hour Open area rate=55% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (19) and pre-expanded styrene-based resin particles (19). The bulk density of the pre-expanded styrene-based resin particles (19) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (19). The density of the styrene-based resin foam molded product (19) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (19) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (19) was evaluated. The results are shown in Table 3.

[0136] Example 20 Expandable styrene-based resin particles (20) were obtained in the same manner as in Example 1, except that the extrusion conditions were as follows: Water pressure = 2.00MPa Discharge amount=200kg / hour Open area rate=53% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (20) and pre-expanded styrene-based resin particles (20). The bulk density of the pre-expanded styrene-based resin particles (20) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (20). The density of the styrene-based resin foam molded product (20) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (20) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (20) was evaluated. The results are shown in Table 3.

[0137] [Reference example 1] The same procedure as in Example 1 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R1). Water pressure = 0.05MPa Discharge amount=200kg / hour Open area rate=69% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (R1) and pre-expanded styrene-based resin particles (R1). The bulk density of the pre-expanded styrene-based resin particles (R1) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (R1). The density of the styrene-based resin foam molded product (R1) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foamed molded product (R1) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R1) was evaluated. The results are shown in Table 3.

[0138] [Reference example 2] The same procedure as in Example 1 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R2). Water pressure = 2.10MPa Discharge amount=200kg / hour Open area rate=38% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (R2) and pre-expanded styrene-based resin particles (R2). The bulk density of the pre-expanded styrene-based resin particles (R2) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foamed molded product (R2). The density of the styrene-based resin foamed molded product (R2) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foamed molded product (R2) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R2) was evaluated. The results are shown in Table 3.

[0139] [Reference example 3] The same procedure as in Example 1 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R3). Water pressure = 0.30MPa Discharge amount=75kg / hour Open area rate=42% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (R3) and pre-expanded styrene-based resin particles (R3). The bulk density of the pre-expanded styrene-based resin particles (R3) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (R3) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (R3) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (R3) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R3) was evaluated. The results are shown in Table 3.

[0140] [Reference example 4] The same procedure as in Example 1 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R4). Water pressure = 0.30MPa Discharge amount=350kg / hour Open area rate=88% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene resin particles (R4) and pre-expanded styrene resin particles (R4). The bulk density of the pre-expanded styrene resin particles (R4) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (R4) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (R4) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (R4) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R4) was evaluated. The results are shown in Table 3.

[0141] [Table 3]

[0142] Example 21 Expandable styrene-based resin particles (21) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=100kg / hour Open area rate=67% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (21) and pre-expanded styrene-based resin particles (21). The bulk density of the pre-expanded styrene-based resin particles (21) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (21). The density of the styrene-based resin foam molded product (21) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (21) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (21) was evaluated. The results are shown in Table 4.

[0143] Example 22 Expandable styrene-based resin particles (22) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=150kg / hour Open area rate=74% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (22) and pre-expanded styrene-based resin particles (22). The bulk density of the pre-expanded styrene-based resin particles (22) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (22). The density of the styrene-based resin foam molded product (22) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (22) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (22) was evaluated. The results are shown in Table 4.

[0144] Example 23 Expandable styrene-based resin particles (23) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=200kg / hour Open area rate=86% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (23) and pre-expanded styrene-based resin particles (23). The bulk density of the pre-expanded styrene-based resin particles (23) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (23). The density of the styrene-based resin foam molded product (23) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (23) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (23) was evaluated. The results are shown in Table 4.

[0145] Example 24 Expandable styrene-based resin particles (24) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=250kg / hour Open area rate=85% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (24) and pre-expanded styrene-based resin particles (24). The bulk density of the pre-expanded styrene-based resin particles (24) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (24). The density of the styrene-based resin foam molded product (24) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (24) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (24) was evaluated. The results are shown in Table 4.

[0146] Example 25 Expandable styrene-based resin particles (25) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.30MPa Discharge amount=300kg / hour Open area rate=85% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (25) and pre-expanded styrene-based resin particles (25). The bulk density of the pre-expanded styrene-based resin particles (25) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (25). The density of the styrene-based resin foam molded product (25) was 0.020 g / cm. 3The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (25) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (25) was evaluated. The results are shown in Table 4.

[0147] Example 26 Expandable styrene-based resin particles (26) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.10MPa Discharge amount=200kg / hour Open area rate=88% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (26) and pre-expanded styrene-based resin particles (26). The bulk density of the pre-expanded styrene-based resin particles (26) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (26). The density of the styrene-based resin foam molded product (26) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (26) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (26) was evaluated. The results are shown in Table 4.

[0148] Example 27 Expandable styrene-based resin particles (27) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.20MPa Discharge amount=200kg / hour Open area rate=87% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (27) and pre-expanded styrene-based resin particles (27). The bulk density of the pre-expanded styrene-based resin particles (27) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (27). The density of the styrene-based resin foam molded product (27) was 0.020 g / cm.3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (27) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (27) was evaluated. The results are shown in Table 4.

[0149] Example 28 Expandable styrene-based resin particles (28) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.50MPa Discharge amount=200kg / hour Open area rate=75% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (28) and pre-expanded styrene-based resin particles (28). The bulk density of the pre-expanded styrene-based resin particles (28) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (28). The density of the styrene-based resin foam molded product (28) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (28) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (28) was evaluated. The results are shown in Table 4.

[0150] Example 29 Expandable styrene-based resin particles (29) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 0.70MPa Discharge amount=200kg / hour Open area rate=74% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (29) and pre-expanded styrene-based resin particles (29). The bulk density of the pre-expanded styrene-based resin particles (29) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (29). The density of the styrene-based resin foam molded product (29) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (29) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (29) was evaluated. The results are shown in Table 4.

[0151] Example 30 Expandable styrene-based resin particles (30) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 1.00MPa Discharge amount=200kg / hour Open area rate=71% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (30) and pre-expanded styrene-based resin particles (30). The bulk density of the pre-expanded styrene-based resin particles (30) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded article (30). The density of the styrene-based resin foam molded article (30) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (30) was dried in a drying chamber at 30°C. The resulting styrene resin foam molded article (30) was evaluated. The results are shown in Table 4.

[0152] Example 31 Expandable styrene-based resin particles (31) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 1.50MPa Discharge amount=200kg / hour Open area rate=60% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (31) and pre-expanded styrene-based resin particles (31). The bulk density of the pre-expanded styrene-based resin particles (31) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded product (31). The density of the styrene-based resin foam molded product (31) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (31) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (31) was evaluated. The results are shown in Table 4.

[0153] Example 32 Expandable styrene-based resin particles (32) were obtained in the same manner as in Example 5, except that the extrusion conditions were as follows: Water pressure = 2.00MPa Discharge amount=200kg / hour Open area rate=53% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (32) and pre-expanded styrene-based resin particles (32). The bulk density of the pre-expanded styrene-based resin particles (32) was 0.020 g / cm. 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foam molded article (32). The density of the styrene-based resin foam molded article (32) was 0.020 g / cm. 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded article (32) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (32) was evaluated. The results are shown in Table 4.

[0154] [Reference example 5] The same procedure as in Example 5 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R5). Water pressure = 0.05MPa Discharge amount=200kg / hour Open area rate=69% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (R5) and pre-expanded styrene-based resin particles (R5). The bulk density of the pre-expanded styrene-based resin particles (R5) was 0.020 g / cm 3The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foamed molded product (R5). The density of the styrene-based resin foamed molded product (R5) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (R5) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R5) was evaluated. The results are shown in Table 4.

[0155] [Reference example 6] The same procedure as in Example 5 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R6). Water pressure = 2.10MPa Discharge amount=200kg / hour Open area rate=42% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene resin particles (R6) and pre-expanded styrene resin particles (R6). The bulk density of the pre-expanded styrene resin particles (R6) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, the same procedure as in Example 1 was carried out to obtain a styrene-based resin foamed molded product (R6). The density of the styrene-based resin foamed molded product (R6) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foamed molded product (R6) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R6) was evaluated. The results are shown in Table 4.

[0156] [Reference example 7] The same procedure as in Example 5 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R7). Water pressure = 0.30MPa Discharge amount=75kg / hour Open area rate=45% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene resin particles (R7) and pre-expanded styrene resin particles (R7). The bulk density of the pre-expanded styrene resin particles (R7) was 0.020 g / cm3 The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (R7) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (R7) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (R7) was dried in a drying chamber at 30°C. The obtained styrene-based resin foamed molded article (R7) was evaluated. The results are shown in Table 4.

[0157] [Reference example 8] The same procedure as in Example 5 was carried out except that the extrusion conditions were as follows, to obtain expandable styrene-based resin particles (R8). Water pressure = 0.30MPa Discharge amount=350kg / hour Open area rate=84% Subsequently, the same procedure as in Example 1 was carried out to obtain surface-treated expandable styrene-based resin particles (R8) and pre-expanded styrene-based resin particles (R8). The bulk density of the pre-expanded styrene-based resin particles (R8) was 0.020 g / cm 3 The bulk ratio was 50 times. Subsequently, a styrene-based resin foam molded product (R8) was obtained in the same manner as in Example 1. The density of the styrene-based resin foam molded product (R8) was 0.020 g / cm 3 The expansion ratio was 50. Thereafter, the styrene-based resin foam molded product (R8) was dried in a drying chamber at 30°C. The obtained styrene-based resin foam molded article (R8) was evaluated. The results are shown in Table 4.

[0158] [Table 4] [Industrial Applicability]

[0159] The expandable styrene-based resin particles, pre-expanded styrene-based resin particles, and styrene-based resin foam molded products according to the embodiment of the present invention are preferably used as heat insulating materials for houses and automobiles, heat retaining materials for building materials, transport packaging materials for fish boxes and food containers, cushioning materials, etc. More specifically, the expandable styrene-based resin particles, pre-expanded styrene-based resin particles, and styrene-based resin foam molded products are preferably used as wall insulation materials, floor insulation materials, roof insulation materials, automobile insulation materials, heat retaining materials for hot water tanks, heat retaining materials for piping, heat retaining materials for solar systems, heat retaining materials for water heaters, containers for food and industrial products, etc., packaging materials for fish and agricultural products, etc., embankment materials, core materials for tatami mats, etc. [Explanation of symbols]

[0160] 1. Extruder 2 Multi-hole die 3 Cutting Room 4. Water Pump 5 Dehydration dryer 6. Aquarium 7 containers 11 Raw material supply hopper 12 Volatile foaming agent supply port 13 High pressure pump 31 Cutter

Claims

1. Expandable styrene-based resin particles containing a resin component containing 70% by mass to 95% by mass of a styrene-based resin and 5% by mass to 30% by mass of a resin other than a styrene-based resin, and a volatile blowing agent, The resin component does not contain a styrene-based elastomer which is a copolymer of styrene and a conjugated diene or a hydrogenated product thereof, The styrene-based resin does not include oxazoline group-containing polystyrene, 50% by mass or more of the styrene-based resin is recycled styrene-based resin, 50% by mass or more of the resin other than the styrene-based resin is a bioplastic, The bioplastic is polylactic acid. Expandable styrene resin particles.

2. A pre-expanded styrene-based resin particle obtained by pre-expanding the expandable styrene-based resin particle according to claim 1, The bulk expansion ratio of the pre-expanded foam is 2 times or more and less than 80 times. Pre-expanded styrene-based resin particles.

3. A styrene-based resin foamed molded article produced from the expandable styrene-based resin particles according to claim 1.

4. A styrene-based resin foamed article produced from the pre-expanded styrene-based resin particles according to claim 2.

5. A method for producing expandable styrene-based resin particles, comprising a resin component containing 70% by mass to 95% by mass of a styrene-based resin and 5% by mass to 30% by mass of a resin other than a styrene-based resin, and a volatile blowing agent, 50% by mass or more of the styrene-based resin is recycled styrene-based resin, 50% by mass or more of the resin other than the styrene-based resin is a bioplastic, the resin composition containing the resin component and the volatile foaming agent is extruded from an extruder and simultaneously cut in water by an underwater cutting method, the water pressure in the underwater cutting method being 0.10 MPa to 2.00 MPa, and the discharge rate being 100 kg / hour to 300 kg / hour; A method for producing expandable styrene-based resin particles.

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