Insulation material

Abstract

To provide an insulation material that exhibits superior flame-retardant performance and heat-resistant performance.SOLUTION: An insulation material is provided, comprising a styrene-based resin foamed molded body satisfying the following (A) to (F): (A) containing a carbon-based radiant heat transfer suppressing agent having an average particle diameter of 1 to 15 μm; (B) containing a bromine-based flame retardant in an amount of more than 0 wt.% and 5.0 wt.% or less relative to 100 wt.% of a resin composition; (C) a first styrene-based resin having a constitutional unit derived from (meth)acrylic acid being contained in an amount of 60 wt.% or more relative to 100 wt.% of a base resin; (D) having flame retardancy of HF-1 or HF-2 in a UL94 flammability test; (E) having a dimensional change rate within ±2% after heating at 90°C for 168 hours; and (F) having an average cell diameter of 90 μm to 400 μm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a heat insulating material made of a foamed molded styrene resin. [Background technology]

[0002] Because of their light weight and excellent thermal insulation properties, thermal insulation materials using polystyrene as a base resin are widely used as thermal insulation materials for residential and industrial use. One way to impart excellent thermal insulation properties to such thermal insulation materials is to incorporate a radiation heat transfer inhibitor such as graphite into the thermal insulation material.

[0003] On the other hand, from the viewpoint of heat resistance, insulating materials using polystyrene as a base resin have a large rate of dimensional change when heated, which may make them difficult to use in high-temperature areas, for example, as insulating materials for hot water containers such as hot water tanks, or as insulating materials for building roofs. One approach to address this problem is to use a copolymer of styrene and another monomer as the base resin, thereby reducing the rate of dimensional change of the foamed molded product and imparting heat resistance (Patent Document 1, Patent Document 2).

[0004] However, foams made from styrene-based resins that contain a radiation heat transfer inhibitor and have heat resistance, as described in Patent Documents 1 and 2, tend to have reduced flame retardancy. In particular, when a carbon-based radiation heat transfer inhibitor, which is highly effective in suppressing radiation heat transfer, is used, the foam becomes more flammable, and the flame retardancy is likely to be significantly reduced. Furthermore, resins in which structural units derived from (meth)acrylic acid are copolymerized with styrene to impart heat resistance have different thermal decomposition temperatures than general styrene resins, resulting in changes in combustion behavior. Therefore, it is difficult to say that systems containing a carbon-based radiation heat transfer inhibitor fully exhibit flame retardancy and heat resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-148661 [Patent Document 2] Japanese Patent Application Publication No. 2023-144509 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a heat insulating material that has excellent flame retardancy and heat resistance. [Means for solving the problem]

[0007] The present invention provides (1) A heat insulating material comprising a styrene-based resin foam molded product that satisfies the following (A) to (F): (A) A carbon-based radiation heat transfer inhibitor having an average particle size of 1 to 15 μm, (B) Contains a brominated flame retardant in an amount of more than 0% by weight and not more than 5.0% by weight based on 100% by weight of the resin composition; (C) a first styrene-based resin having a structural unit derived from (meth)acrylic acid is contained in an amount of 60% by weight or more relative to 100% by weight of the base resin; (D) Has flame retardancy of HF-1 or HF-2 in the UL94 flame test. (E) The dimensional change rate after heating at 90°C for 168 hours is within ±2%. (F) The average cell diameter is 90 μm or more and 400 μm or less; (2) The heat insulating material according to (1), wherein the content of the heat stabilizer is more than 0% by weight and 10% by weight or less, based on 100% by weight of the total amount of the brominated flame retardant and the heat stabilizer. (3) The heat insulating material according to (1) or (2), wherein the oxygen index of the styrene-based resin foam molded body is 26% by volume or more and 33% by volume or less. (4) The density of the styrene-based resin foam molded body is 15 kg / m 3 ~40kg / m 3 The heat insulating material according to (1) or (2), (5) The heat insulating material according to (1) or (2), wherein the laser scattering intensity per unit solution concentration of the radiation heat transfer inhibitor in the styrene-based resin foam molded product is 3.5 {% / (mg / ml)} / wt% or more. (6) The heat insulating material according to (1) or (2), wherein the thermal conductivity of the styrene-based resin foam molded body is 0.030 W / mK or less. (7) The heat insulating material according to (1) or (2), wherein the first styrene-based resin is a styrene-based resin having 2 to 20% by weight of a structural unit derived from (meth)acrylic acid. (8) Water absorption rate conforming to JIS A 9511: 1.0g / 100cm 2 The heat insulating material according to (1) or (2), which is: (9) The heat insulating material according to (1) or (2), wherein the styrene-based resin foamed molded body is a foamed bead molded body. (10) The foamed particles are formed by foaming an expandable styrene-based resin, The heat insulating material according to (9), wherein the expandable styrene resin particles contain 0.05 parts by weight or more and 0.30 parts by weight or less of zinc stearate per 100 parts by weight of the expandable styrene resin particles. (11) The heat insulating material according to (9), wherein the fusion rate of the foamed particles of the styrene-based resin foamed molded article is 70% or more. Regarding. [Effects of the Invention]

[0008] The heat insulating material of the present invention exhibits excellent flame retardancy and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Base resin> The styrene-based resin used in this embodiment is preferably a styrene homopolymer and / or a copolymer of styrene with another monomer or a derivative thereof.

[0010] Examples of the "other monomers or derivatives thereof" include: (a) styrene derivatives such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene; (b) polyfunctional vinyl compounds such as divinylbenzene; (c) (meth)acrylic acid compounds such as acrylic acid and methacrylic acid; (d) methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and (e) vinyl cyanide compounds such as (meth)acrylonitrile; (f) diene compounds or derivatives thereof such as butadiene; (g) unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; and N-alkyl-substituted maleimide compounds such as N-methylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(2)-chlorophenylmaleimide, N-(4)-bromophenylmaleimide, and N-(1)-naphthylmaleimide. These may be used alone or in combination of two or more.

[0011] In this embodiment, the base resin of the styrene-based resin foam molded article contains a first styrene-based resin having structural units derived from (meth)acrylic acid. Specifically, the first styrene-based resin may be a styrene-(meth)acrylic acid copolymer. The structural units derived from (meth)acrylic acid in the first styrene-based resin are preferably 2 to 20% by weight, more preferably 2 to 15% by weight, and even more preferably 3 to 12% by weight.

[0012] In the present embodiment, the first styrene-based resin preferably has a Vicat softening point of 106° C. or more and 125° C. or less. The Vicat softening point is measured according to JIS K 7206.

[0013] In this embodiment, the melt mass flow rate (MFR) of the first styrene-based resin is preferably 0.5 to 5 g / 10 min, more preferably 1 to 4 g / 10 min, from the viewpoint of ensuring the molding processability and strength of the heat insulating material. The MFR is measured according to JIS K 7210.

[0014] In this embodiment, the composition may further contain a second styrene-based resin different from the first styrene-based resin. The second styrene-based resin preferably has a Vicat softening point of 95°C or higher and 105°C or lower. The second styrene-based resin is preferably a styrene homopolymer and / or a copolymer of styrene and another monomer or a derivative thereof. Among these, at least one selected from the group consisting of a styrene homopolymer, a styrene-acrylonitrile copolymer, a styrene-methyl(meth)acrylate copolymer, and a styrene-butyl(meth)acrylate copolymer is preferred because they are relatively inexpensive, can be foam-molded using low-pressure steam or the like without using a special method, and have an excellent balance of heat insulation, flame retardancy, and cushioning properties.

[0015] In this embodiment, the first styrene-based resin is preferably the main component of the entire base resin. The term "main component" as used herein means 50% by weight or more of the entire base resin. The content of the first styrene-based resin relative to the entire base resin is preferably 60% by weight or more and 100% by weight or less. It is more preferably 70% by weight or more and 100% by weight or less, even more preferably 70% by weight or more and 95% by weight or less, even more preferably 70% by weight or more and 85% by weight or less, and even more preferably 70% by weight or more and 80% by weight or less. When the content of the first styrene-based resin is 60% by weight or more, a foamed molded article with excellent heat resistance can be obtained.

[0016] In this embodiment, when the second styrene-based resin is contained, it is preferably 0% by weight or more and 50% by weight or less, more preferably 5% by weight or more and 30% by weight or less, even more preferably 15% by weight or more and 30% by weight or less, and even more preferably 20% by weight or more and 30% by weight or less, based on the entire base resin.

[0017] In this embodiment, the base resin constituting the styrene-based foam molded article may contain other resins in addition to the styrene-based resin. Examples of such resins include vinyl resins such as polymethyl methacrylate, polyacrylonitrile resin, and vinyl chloride resin; polyolefin resins such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-butene terpolymer, and cycloolefin (co)polymer; polyolefin resins having a branched or crosslinked structure introduced therein to control the rheology; polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, and MXD nylon; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyarylate, and polycarbonate; aliphatic polyester resins such as polylactic acid; and engineering plastics such as polyphenylene ether resin (PPE), modified polyphenylene ether resin (modified PPE), polyoxymethylene resin, polyphenylene sulfide resin, polyphenylene sulfide resin, aromatic polyether resin, and polyether ether ketone resin.

[0018] <Brominated flame retardants> The bromine-based flame retardant contained in the thermal insulating material according to one embodiment of the present disclosure is not particularly limited, and various flame retardants can be used. In one preferred embodiment, a bromine atom is attached to an aliphatic carbon.

[0019] Examples of brominated flame retardants include brominated bisphenol compounds, brominated styrene-butadiene copolymers, and brominated isocyanurate compounds. Specific examples of brominated bisphenol compounds include 2,2-bis[4-(2,3-dibromo-2-methylpropoxy)-3,5-dibromophenyl]propane (also known as tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether)), 2,2-bis[4-(2,3-dibromopropoxy)-3,5-dibromophenyl]propane (also known as tetrabromobisphenol A-bis(2,3-dibromopropyl ether)), and the like. Brominated styrene-butadiene copolymers include brominated styrene-butadiene block copolymers, brominated random styrene-butadiene copolymers, and brominated styrene-butadiene graft copolymers. Examples of brominated isocyanurate compounds include tris(2,3-dibromopropyl)isocyanurate, etc. Other compounds include tetrabromocyclooctane, etc. These brominated flame retardants may be used alone or in combination of two or more.

[0020] The content of the brominated flame retardant in the entire insulating material is more than 0% by weight and not more than 5.0% by weight. Preferably, it is 0.5% by weight or more and 4.5% by weight or less, more preferably 1.0% by weight or more and 4.0% by weight or less, and even more preferably 1.5% by weight or more and 4.0% by weight or less. If the content of the brominated flame retardant is more than 0% by weight, a certain level of flame retardancy can be achieved. If the content of the brominated flame retardant is 5.0% by weight or less, adverse effects on the dimensional change rate of the insulating material at 90°C can be suppressed.

[0021] In this embodiment, a flame retardant other than the brominated flame retardant may be added as long as the effect of this embodiment is not impaired. The flame retardants used in styrene-based resin foams can be used in the same manner.

[0022] <Heat stabilizer> In one embodiment of the present disclosure, a thermal stabilizer may be included. The inclusion of a thermal stabilizer can suppress deterioration of flame retardancy due to decomposition of the brominated flame retardant during the manufacturing process and deterioration of the expandable styrene resin foam particles, as described below. The thermal stabilizer is not particularly limited and may be appropriately selected depending on the type of base resin, the type and content of the blowing agent, the type and content of the radiant heat transfer inhibitor, the type and content of the brominated flame retardant, and the like. Examples of thermal stabilizers include hindered amine compounds, phosphorus-based compounds, and epoxy compounds, with hindered amine compounds and phosphorus-based compounds being particularly preferred. These thermal stabilizers may be used alone or in combination of two or more. The content of the thermal stabilizer relative to 100% by weight of the total amount of the brominated flame retardant and the thermal stabilizer is preferably more than 0% by weight and not more than 10% by weight. It is more preferably 1% by weight to 8% by weight, and even more preferably 2% by weight to 6% by weight.

[0023] <Radiation heat transfer inhibitor> A heat insulating material according to one embodiment of the present disclosure can exhibit high heat insulating properties by including a radiation heat transfer inhibitor having an average particle size of 1 to 15 μm. Here, the term "radiation heat transfer inhibitor" refers to a substance that has the property of reflecting, scattering, or absorbing light in the infrared region (e.g., a wavelength region of about 0.8 μm to 100 μm).

[0024] The radiation heat transfer inhibitor is not particularly limited, but carbon-based radiation heat transfer inhibitors are preferred in terms of dispersibility in styrene-based resins and cost. Examples of carbon-based radiation heat transfer inhibitors include graphite, carbon black, activated carbon, graphene, and carbon nanotubes, with graphite being more preferred. That is, it is particularly preferred that the radiation heat transfer inhibitor contains graphite as a main component. Here, "contains as a main component" refers to a content ratio of more than 50 wt%. In a preferred embodiment, the content ratio of graphite relative to the entire radiation heat transfer inhibitor is more than 50 wt%, more preferably 80 wt% or more, even more preferably 90 wt% or more, and particularly preferably 100 wt% (total amount).

[0025] Examples of the graphite include flake graphite, amorphous graphite, spherical graphite, and artificial graphite. In the present disclosure, the term "flake" also includes scaly, thin, or plate-like graphite. These graphites can be used alone or in combination of two or more. Among these, a graphite mixture containing flake graphite as a main component is preferred, and flake graphite is more preferred, because of its high radiation heat transfer suppression effect.

[0026] Examples of radiation heat transfer inhibitors other than carbon-based radiation heat transfer inhibitors include aluminum-based compounds, zinc-based compounds, magnesium-based compounds, titanium-based compounds, heat ray reflectors, metal sulfates, antimony-based compounds, metal oxides, heat ray absorbers, metal particles, etc. Specific examples include titanium oxide, aluminum, copper, etc.

[0027] The above-mentioned radiation heat transfer inhibitors may be used alone or in combination of two or more.

[0028] The average particle size of the radiation heat transfer inhibitor in the present disclosure is 1 μm or more and 15 μm or less. 12 μm or less and 2 μm or more is preferred, 10 μm or less and 2 μm or more is more preferred, and 7 μm or less and 2 μm or more is even more preferred. By setting the average particle size to 15 μm or less, the moldability during foam molding of the resin particles is improved, and by setting it to 1 μm or more, handling is possible without impairing handleability. Note that the average particle size of the radiation heat transfer inhibitor referred to here refers to the particle size D50 (i.e., 50% volume cumulative particle size) at which the cumulative volume of the total particles is 50% as measured and analyzed by a laser diffraction scattering method based on Mie theory in accordance with ISO 13320:2009 and JIS Z8825-1.

[0029] The content of the radiation heat transfer inhibitor is not particularly limited, but for example, the content ratio of the radiation heat transfer inhibitor to the heat insulating material can be 2.0% by weight or more and 10.0% by weight or less, 3.0% by weight or more and 8.0% by weight or less, etc. With this blending amount, desired heat insulating properties can be achieved.

[0030] <Laser scattering intensity> In a heat insulating material according to one embodiment of the present disclosure, the laser scattering intensity per unit solution concentration of the radiation heat transfer inhibitor in the heat insulating material (styrene-based resin foam molded article) is preferably 3.5% / (mg / ml) / wt% or more. When the laser scattering intensity is equal to or greater than a predetermined value, the dispersion of the radiation heat transfer inhibitor in the heat insulating material is favorable. As a result, the thermal conductivity of the heat insulating material is reduced, and the heat insulating performance is improved. Specific methods for measuring the laser scattering intensity will be described in the examples below.

[0031] In one embodiment of the present disclosure, the insulating material may contain a blowing agent. The blowing agent is not particularly limited, but from the viewpoint of ease of achieving a high blowing ratio in actual use, volatile blowing agents are preferred, saturated hydrocarbons are more preferred, and aliphatic hydrocarbons having 4 or 5 carbon atoms are even more preferred. Examples of such hydrocarbons include normal butane, isobutane, normal pentane, isopentane, neopentane, cyclopentane, etc. These blowing agents may be used alone or in combination of two or more. In one preferred embodiment, the blowing agent contains an aliphatic hydrocarbon having 4 carbon atoms and / or an aliphatic hydrocarbon having 5 carbon atoms. In another preferred embodiment, the blowing agent contains at least an aliphatic hydrocarbon having 5 carbon atoms. Other blowing agents that may be used in this embodiment include hydrofluoroolefins, hydrochlorofluoroolefins, hydrofluorocarbons, nitrogen, carbon dioxide, etc.

[0032] The amount of foaming agent is not particularly limited, but for example, when the insulating material is 100% by weight, the amount of foaming agent is 10% by weight or less. Preferably, it is 5% by weight or less. If the content is 5% by weight or less, it is possible to suppress adverse effects on the dimensional change rate of the insulating material at 90°C.

[0033] <Other ingredients> The heat insulating material according to one embodiment of the present disclosure may further contain other components within a range that does not impair its performance, such as external additives, stabilizers, radical generators, processing aids, light resistance stabilizers, nucleating agents, foaming aids, antistatic agents, colorants such as pigments, etc.

[0034] <Insulating material manufacturing method> The method for producing the thermal insulating material according to one embodiment of the present disclosure is not particularly limited, but a first production method includes a step of preparing a resin melt containing a base resin, a radiant heat transfer inhibitor, a flame retardant, a foaming agent, and, as necessary, various additives, and extruding the resin melt through a die having a plurality of small holes into pressurized circulating water, cutting the resulting expandable styrene-based resin particles with a rotary cutter, and pre-expanding and molding the resulting expandable styrene-based resin particles to produce a thermal insulating material.

[0035] A second manufacturing method is a method for manufacturing a heat insulating material in which a base resin, a radiation heat transfer inhibitor, a flame retardant, and, if necessary, various additives such as a radical generator and a heat stabilizer are melt-kneaded in an extruder, extruded through a die having many small holes, and then cut with a cutter to obtain resin particles (cold cut method or hot cut method), and the resin particles are suspended in water and impregnated with a blowing agent to obtain expandable styrene-based resin particles, which are then pre-expanded and molded.

[0036] The first production method will be described below.

[0037] <Method for producing expandable styrene resin particles> First, a base resin, a radiation heat transfer inhibitor, a brominated flame retardant, and other components as needed are melt-kneaded in an extruder. In this specification, the composition obtained by melt-kneading a base resin, a radiation heat transfer inhibitor, a brominated flame retardant, and additives as needed is referred to as a resin composition.

[0038] Next, a blowing agent is dissolved and dispersed in the molten mixture using an extruder or a mixing device installed downstream of the extruder. Next, the molten mixture containing the blowing agent is extruded through a die with many small holes installed downstream of the extruder or the mixing device into a cutter chamber filled with pressurized circulating water. Immediately after extrusion, the molten mixture is cut with a rotary cutter and cooled and solidified with pressurized circulating water. This produces the desired expandable styrene resin particles. The melt-kneading using an extruder can be performed using a single extruder, multiple extruders connected together, or a second kneading device such as an extruder, a static mixer, or a mixer without a screw, and can be selected as appropriate.

[0039] In one embodiment of the present disclosure, zinc stearate is preferably externally added to the expandable styrene-based resin particles. The amount of zinc stearate is preferably 0.05 parts by weight or more and 0.30 parts by weight or less per 100 parts by weight of the expandable styrene-based resin particles. More preferably, it is 0.10 parts by weight or more and 0.25 parts by weight or less, and even more preferably, it is 0.15 parts by weight or more and 0.25 parts by weight or less. When the amount of zinc stearate as an external additive is 0.05 parts by weight or more, it is possible to prevent the expanded particles from adhering to each other during pre-expansion, and also to improve the fusion of the expanded particles to each other during molding. When the amount of zinc stearate is 0.30 parts by weight or less, it is possible to prevent clogging of the slits in the mold during molding. In addition to zinc stearate, commonly used external additives may be used in the expandable styrene-based resin particles.

[0040] <Method of manufacturing styrene resin foam molded article> A known method can be used to produce a foamed molded article using the expandable styrene-based resin particles. For example, the expandable styrene-based resin particles are pre-expanded to produce pre-expanded resin particles. The pre-expanded resin particles are then molded using a molding machine to produce a foamed molded styrene-based resin article.

[0041] In this specification, a foamed molded product from which the blowing agent has been dispersed after heating at 70°C for 30 days is considered to be synonymous with a resin composition.

[0042] <Pre-expanded resin particles> Pre-expanded resin particles can be produced, for example, by expanding expandable styrene-based resin particles 10 to 110 times with heated steam. The pre-expanded resin particles are used for molding after being cured for a certain period of time, if necessary. The obtained pre-expanded resin particles are molded (e.g., molded in a mold) with steam using a known molding machine to produce a heat insulating material. Depending on the shape of the mold used, molded articles with complex shapes and block-shaped molded articles can be obtained.

[0043] <Insulation density> In one embodiment of the present disclosure, the density of the insulating material is 15 to 40 kg / m 3 is preferably 18 to 30 kg / m 3 By satisfying the above range, the heat insulating performance and strength characteristics are excellent, and the heat insulating material is durable enough for residential and industrial use.

[0044] <Cell diameter of the insulation material> In one embodiment of the present disclosure, the average cell diameter constituting the thermal insulating material is preferably 90 μm or more and 400 μm or less. It is more preferably 100 μm to 350 μm. If the average cell diameter exceeds 400 μm, the number of cell membranes in the thermal insulating material decreases, and sufficient thermal insulating performance may not be obtained. Furthermore, if the average cell diameter is less than 90 μm, the cell membrane thickness becomes extremely thin, which may lead to a decrease in the closed cell ratio of the thermal insulating material, a decrease in thermal insulating performance, a decrease in strength, and a decrease in heat resistance.

[0045] <Thermal conductivity of insulation material> In one embodiment of the present disclosure, the thermal conductivity is preferably 0.0300 W / mK or less, more preferably 0.0298 W / mK or less, and even more preferably 0.0297 W / mK or less. The thermal conductivity is measured by a heat flow meter method in accordance with JIS A1412-2:1999, and the thermal conductivity at a temperature difference of 20°C is used.

[0046] <Dimensional change rate of insulation material> In one embodiment of the present disclosure, the dimensional change rate of the insulating material after heating for 24 hours in a 90°C atmosphere is within ±2%. Preferably, it is within ±1.8%, more preferably within ±1.6%, and even more preferably within ±1.4%. Within the above range, an insulating material with excellent dimensional stability even in high-temperature environments can be provided, and the material has excellent durability. The measurement conditions will be described later.

[0047] <Flame retardant performance of insulation materials> In one aspect of the present disclosure, a thermal insulation material with excellent flame retardancy is provided by incorporating a brominated flame retardant into the thermal insulation material. By incorporating a brominated flame retardant into the thermal insulation material, it is possible to provide a thermal insulation material that satisfies HF-2, preferably HF-1, in the horizontal combustion test for foams specified in UL94. Because of this flame retardancy, the thermal insulation material can be used as a thermal insulation material for electrical appliances. The measurement conditions will be described later.

[0048] By incorporating a brominated flame retardant into the insulating material of the present disclosure, it is possible to provide an insulating material having flame retardancy with an oxygen index of 26% by volume or more and 33% by volume or less, preferably 26.5% by volume or more and 32% by volume or less. By having an oxygen index of 26% by volume or more, the desired flame retardancy can be achieved.

[0049] <Water absorption characteristics of insulation material> In one embodiment of the present disclosure, the water absorption property of the heat insulating material is a water absorption amount of 1.0 g / 100 cm according to JIS A 9511. 2 It is preferably 0.5 g / 100 cm or less, and more preferably 0.5 g / 100 cm 2 Below that, preferably 0.2 g / 100 cm 2 When the water absorption amount of the heat insulating material is within the above range, the heat insulating performance is less likely to be reduced due to water absorption, and high heat insulating performance is maintained for a long period of time.

[0050] <Fusion rate of insulation material> In one embodiment of the present disclosure, the fusion rate of the expanded beads in the styrene-based resin expansion molded article is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. A fusion rate of 70% or more increases the fusion between the expanded beads, thereby increasing the strength of the thermal insulating material.

[0051] The heat insulating material having the above-mentioned properties is suitable for use as a heat insulating material for houses, warehouses, roofs, hot water tanks, etc., but is not limited to these uses. [Example]

[0052] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0053] Example 1 [Preparation of expandable styrene resin particles] The composition consisted of 94% by weight of methacrylic acid-modified styrene resin (G9001 manufactured by PS Japan Co., Ltd., 8% by weight of methacrylic acid, Vicat softening point: 124°C, MFR: 1.5g / 10min), 4.5% by weight of graphite (SGP-40B flake graphite manufactured by Marutoyo Foundry Co., Ltd., average particle size: 5.8μm), and 4.5% by weight of bromine-based flame retardant (GR-170P (2,2-bis[4-(2,3-dibromo A mixture of 95 wt% (2-methylpropoxy)-3,5-dibromophenyl)propane and 1.5 wt% (a mixture of 2 wt% tetrakis(2,2,6,6-tetramethylpiperidyloxycarbonyl)butane and 3 wt% bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite) as a thermal stabilizer was fed into a 40 mm diameter co-rotating intermeshing twin-screw extruder (first extruder). The cylinder temperature after the raw material feed section of the twin-screw extruder was set to 200°C, and the feed was melt-kneaded. Next, 8.0 wt% of mixed pentane (a mixture of 80 wt% normal pentane and 20 wt% isopentane (manufactured by SK Sangyo Co., Ltd.)) as a blowing agent was injected into the middle of the cylinder after the raw material feed section of the twin-screw extruder, and further melt-kneaded.

[0054] The resulting thermoplastic resin melt (the thermoplastic resin melt containing the foaming agent) was then fed to a 90 mm diameter single-screw extruder (second extruder) through a continuation pipe set at 200°C. A gear pump set at 180°C and a diverter valve were connected to the tip of the single-screw extruder. A die set at 250°C and equipped with 60 small holes with a diameter of 0.65 mm and a land length of 5.0 mm was connected downstream of the diverter valve. The cylinder temperature of the single-screw extruder was then set to 170°C to knead the thermoplastic resin melt. The melt obtained by melt kneading was then extruded through the die connected to the tip of the single-screw extruder at an extrusion rate (discharge) of 60 kg / hr into pressurized water at a temperature of 70°C and a water pressure of 0.9 MPa.

[0055] Immediately after that, the molten material was cut into particles using a rotary cutter with a blade. This produced expandable styrene resin particles for in-mold molding. The average particle weight of the resulting expandable styrene resin particles was 1 mg.

[0056] 0.2 parts by weight of zinc stearate as an external additive was externally added to the obtained expandable styrene resin particles, and dry blending was carried out to obtain the external additive-coated expandable styrene resin particles, which were then used for pre-expansion.

[0057] [Formation of pre-expanded particles] The obtained expandable styrene resin particles were placed in a pre-expanding machine and expanded by introducing steam at 0.1 MPa. This resulted in the formation of pre-expanded particles. The bulk expansion ratio of the obtained pre-expanded particles was 50 times (cc / g).

[0058] [Making insulation] The obtained pre-expanded particles were filled into a mold (mold for in-mold molding) attached to a molding machine for styrene foam, and steam of 0.08 MPa was introduced to cause in-mold foaming. After that, the resin foam molded body in the mold was cooled with water until the pressure pressing the mold was 0.015 MPa (gauge pressure). Then, it was measured in a size of 400 mm long x 400 mm wide x 25 mm thick, with a density of 20 kg / m 3A heat insulating material (hereinafter sometimes referred to as "styrene-based resin heat insulating material") made of the above styrene-based resin foam molded article was produced.

[0059] Example 2 A styrene-based resin heat insulating material was produced in the same manner as in Example 1, except that the amount of G9001, a methacrylic acid-modified styrene-based resin, was changed to 93.5% by weight and the amount of GR170P, a bromine-based flame retardant, was changed to 2.0% by weight.

[0060] Example 3 A styrene-based resin heat insulating material was produced in the same manner as in Example 1, except that the amount of G9001, a methacrylic acid-modified styrene-based resin, was changed to 93.0 wt % and the amount of GR170P, a bromine-based flame retardant, was changed to 2.5 wt %.

[0061] Example 4 A styrene-based resin heat insulating material was produced in the same manner as in Example 1, except that the base resin was changed to 74.4% by weight of methacrylic acid-modified styrene-based resin MR100 (manufactured by PS Japan Co., Ltd.: MR100, methacrylic acid 4% by weight, Vicat softening point: 109°C, MFR: 2.3g / 10min), 18.6% by weight of polystyrene resin 680 (manufactured by PS Japan Co., Ltd.: 680, Vicat softening point: 97°C, MFR: 8g / 10min), and 2.5% by weight of brominated flame retardant GR170P.

[0062] Example 5 A styrene-based resin insulation material was prepared in the same manner as in Example 1, except that the base resin was changed to 74.0 wt% MR100 as a methacrylic acid-modified styrene-based resin, 18.5 wt% 680 as a polystyrene resin, and 3.0 wt% GR170P, a brominated flame retardant.

[0063] Example 6 A styrene-based resin insulation material was prepared in the same manner as in Example 1, except that the base resin was changed to 73.6 wt% MR100 as a methacrylic acid-modified styrene-based resin, 18.4 wt% 680 as a polystyrene resin, and 3.5 wt% GR170P, a brominated flame retardant.

[0064] (Comparative Example 1) A styrene-based resin insulation material was produced in the same manner as in Example 1, except that the base resin was changed to 76.4 wt% MR100 as a methacrylic acid-modified styrene-based resin, 19.1 wt% 680 as a polystyrene resin, and the brominated flame retardant GR170P was changed to 0 wt%.

[0065] (Comparative Example 2) A styrene-based resin insulation material was produced using the same process as in Example 1, except that the base resin was changed to 93% by weight of polystyrene-based resin 680 and 2.5% by weight of brominated flame retardant GR170P.

[0066] Various properties of the heat insulating materials produced in each experimental example were measured by the following methods.

[0067] <Measurement of average particle size D50 and laser scattering intensity (%) of graphite> (1) Preparation of sample solution 500 mg of the insulating material was dissolved and dispersed in 20 mL of a 0.1% (w / w) Span 80 toluene solution to prepare a sample solution. The above-mentioned dissolution and dispersion refers to a state in which the resin is dissolved and the graphite is dispersed. The 0.1% (w / w) Span 80 toluene solution refers to toluene to which 0.1% (w / w) of the surfactant Span 80 has been added. Next, the sample solution was irradiated with ultrasonic waves in an ultrasonic cleaner to relax the aggregation of graphite. (2) Ultrasonic irradiation conditions Equipment used: AS ONE Corporation ultrasonic cleaner, model USM Oscillation frequency: 42kHz Irradiation time: 10 minutes Temperature: room temperature (3) Particle size measurement conditions Measurement equipment: Malvern Laser Diffraction Particle Size Distribution Analyzer Mastersizer 3000 Light source: 632.8nm red He-Ne laser and 470nm blue LED Dispersion unit: Wet dispersion unit Hydro MV The analysis was carried out under the following settings. The volume distribution was determined and the D50 particle size of the graphite in the sample was calculated by measurement and analysis using a laser diffraction / scattering method based on the Mie theory in accordance with ISO13320:2009 and JIS Z8825-1. Particle type: non-spherical Graphite refractive index: 2.42 Graphite absorption rate: 1.0 Dispersion medium: 0.1% (w / w) Span 80 toluene solution Refractive index of dispersion medium: 1.49 Agitation speed in dispersion unit: 2500 rpm Analysis model: General, single mode preserving Measurement temperature: room temperature (4) Measurement procedure 120 mL of 0.1% (w / w) Span 80 toluene solution was poured into the dispersion unit and stirred at 2500 rpm to stabilize. The light intensity measured by the central detector when irradiating the dispersion medium with a 632.8 nm red He-Ne laser beam without the sample solution sample in the measurement cell was taken as the transmitted light intensity Lb. Next, 2 mL of the ultrasonically treated sample solution was taken and added to the dispersion unit. One minute after adding the sample solution, the light intensity measured by the central detector when irradiating the dispersion medium with a 632.8 nm red He-Ne laser beam was taken as the transmitted light intensity Ls. The particle diameter (D50) was also measured at the same time. The laser scattering intensity Ob of the sample solution was calculated from the obtained Ls and Lb using the following formula: Ob = (1 - Ls / Lb) x 100 (%) The central detector is a detector located in front of the laser light output, and the light detected here is a measure of the transmitted light that was not used for scattering. The laser scattering intensity is a measure of the amount of laser light lost when the sample scatters the laser of the analytical device. (5) Calculation of laser scattering intensity per unit solution concentration of insulating material The laser scattering intensity X (% / (mg / ml)) per unit solution concentration of the heat insulating material was calculated using the following formula. X (% / (mg / ml)) = laser scattering intensity (Ob) / {sample weight (500 mg) / toluene amount (20 mL) × sample injection amount (2 mL) / total toluene amount in dispersion unit (120 mL + 2 mL)} Here, the laser scattering intensity per unit solution concentration is the value obtained by dividing the measured laser scattering intensity by the sample concentration in toluene. Because the measurement device used here is an instrument that requires measurement in solution, the sample concentration in the toluene solution was kept constant, and measurements were obtained for a constant sample amount. (6) Calculation of laser scattering intensity per unit solution concentration of radiation heat transfer inhibitor in insulation material The laser scattering intensity Y {% / (mg / ml)} / wt % per unit solution concentration of the radiation heat transfer inhibitor contained in the heat insulating material (hereinafter abbreviated as "measurement object") was calculated using the following formula. Y{% / (mg / ml)} / weight% = laser scattering intensity per unit solution concentration of the target (% / (mg / ml)) / graphite content of the target (weight%).

[0068] <Insulation density> A sample measuring 300 mm in length, 300 mm in width, and 25 mm in thickness was cut out from the styrene-based resin foam molded body. The weight (kg) of the sample was measured, and the length, width, and thickness were measured using a vernier caliper. The volume (m 3 ) was calculated, and the density was calculated according to the following formula. Insulation density (kg / m 3 ) = sample weight (kg) / sample volume (m 3 ).

[0069] <Insulation foaming ratio> A sample measuring 300 mm in length, 300 mm in width, and 25 mm in thickness was cut out from the styrene-based resin foam molded article. The weight (g) of the sample was measured, and the length, width, and thickness were measured using a vernier caliper. The volume (cm) of the sample was calculated from the measured dimensions. 3 ) was calculated, and the expansion ratio was calculated according to the following formula. Foaming ratio (cm 3 / g) = specimen volume (cm 3 ) / test piece weight (g) The expansion ratio of styrene resin foam moldings is conventionally expressed as "cm 3 It is also expressed as " / g".

[0070] <Average cell diameter of insulation material> The styrene-based resin foam molded body was cut with a razor and the cross section was observed under an optical microscope. The number of cells present within a 1,000 μm x 1,000 μm square area of ​​the cross section was counted, and the value calculated using the following formula (area average diameter) was taken as the average cell diameter. The average cell diameter of five samples was measured, and the average was taken as the average cell diameter of the standard. Average cell diameter (μm) = 2 × [1000 μm × 1000 μm / (number of cells × π)] 1 / 2 .

[0071] <Measurement of thermal conductivity of insulation materials> A sample measuring 300 mm in length, 300 mm in width, and 25 mm in thickness was cut out from the styrene-based resin foam molded article. The sample was left standing at 23°C for one month, and then its thermal conductivity was measured using a thermal conductivity measuring device (HC-074, manufactured by Eiko Seiki Co., Ltd.) at an average temperature of 23°C and a temperature difference of 20°C by the heat flow meter method in accordance with JIS A1412-2:1999.

[0072] <Measurement of dimensional change rate of insulation material> A sample measuring 150 mm in length, 150 mm in width, and 25 mm in thickness was cut from a styrene-based resin foam molded article. The sample was left to stand at 23°C for 168 hours, and then three parallel lines were drawn in the vertical and horizontal directions at 50 mm intervals in the center of the specimen. The specimen was then placed in a hot air circulation dryer at 90°C for 168 hours, after which it was removed and left under standard conditions (temperature 23±2°C, humidity 50±5%) for one hour. The dimensions of the vertical and horizontal lines were measured, and the thermal dimensional change rate S (%) was calculated using the following formula. S = (L1 - L0) / L0 x 100 In the formula, S represents the rate of dimensional change upon heating (%), L0 represents the dimension (mm) before heating, and L1 represents the dimension (mm) after heating.

[0073] <Evaluation of flame retardancy> <ul 94 発泡体水平燃焼試験> The styrene resin foam molded product was left to stand at 23°C for one month, and five test pieces measuring 150mm long x 50mm wide x 13mm thick were cut out.The foam was then subjected to a horizontal combustion test in accordance with UL94 Seventh Edition to determine its compliance class. Compliance with HF-1 and HF-2 is judged in accordance with UL94 Seventh Edition. Although it does not comply with the legal class of UL94 Seventh Edition, if the damaged length of the test piece exceeds 60 mm, it is judged as ×.

[0074] <Oxygen index> The styrene resin foam molded article was left standing at 70°C for 168 hours and then at 23°C for 24 hours, after which the oxygen index was measured in accordance with JIS K7201.

[0075] <Evaluation of the fusion rate of heat insulating materials> The styrene-based resin foam molded article was broken, and the fracture surface was visually observed to determine the area of ​​the entire fracture surface where the particles themselves, rather than the particle interfaces, were broken, and the percentage (%) of the area where the particles themselves were broken relative to the entire area of ​​the fracture surface was calculated.

[0076] <Water absorption of insulation material> A sample measuring 100 mm in length, 100 mm in width, and 25 mm in thickness was cut out from the styrene-based resin foam molded article. The water absorption of the sample was measured according to the water absorption measurement method of JIS A 9511 Test Method A.

[0077] [Table 1]

Claims

1. A heat insulating material comprising a styrene-based resin foam molded product satisfying the following (A) to (F): (A) a carbon-based radiation heat transfer inhibitor having an average particle size of 1 to 15 μm; (B) Contains a brominated flame retardant in an amount of more than 0% by weight and not more than 5.0% by weight based on 100% by weight of the resin composition; (C) a first styrene-based resin having a structural unit derived from (meth)acrylic acid is contained in an amount of 60% by weight or more relative to 100% by weight of the base resin; (D) has a flame retardancy of HF-1 or HF-2 in the UL94 flame test; (E) The dimensional change rate after heating at 90°C for 168 hours is within ±2%. (F) The average cell diameter is 90 μm or more and 400 μm or less.

2. 2. The heat insulating material according to claim 1, wherein the content of the heat stabilizer is more than 0% by weight and 10% by weight or less, relative to 100% by weight of the total amount of the brominated flame retardant and the heat stabilizer.

3. 3. The heat insulating material according to claim 1, wherein the styrene-based resin foamed molded article has an oxygen index of 26% by volume or more and 33% by volume or less.

4. The density of the styrene resin foam molded article is 15 kg / m ３ ~40 kg / m ３ The heat insulating material according to claim 1 or 2,

5. 3. The heat insulating material according to claim 1, wherein the laser scattering intensity per unit solution concentration of the radiation heat transfer inhibitor in the styrene-based resin foam molded article is 3.5% / (mg / ml) / wt% or more.

6. 3. The heat insulating material according to claim 1, wherein the styrene-based resin foam molded body has a thermal conductivity of 0.030 W / mK or less.

7. 3. The heat insulating material according to claim 1, wherein the first styrene-based resin is a styrene-based resin having 2 to 20% by weight of a structural unit derived from (meth)acrylic acid.

8. Water absorption according to JIS A 9511: 1.0g / 100cm ２ 3. The heat insulating material according to claim 1 or 2, wherein:

9. 3. The heat insulating material according to claim 1, wherein the styrene resin foam molded body is a foam bead molded body.

10. The expanded beads are obtained by expanding an expandable styrene-based resin, The heat insulating material according to claim 9, wherein the expandable styrene-based resin particles contain 0.05 parts by weight or more and 0.30 parts by weight or less of zinc stearate per 100 parts by weight of the expandable styrene-based resin particles.

11. The heat insulating material according to claim 9, wherein the fusion rate of the foamed particles of the styrene-based resin foam molded article is 70% or more.

Images