Flame retardant composition for foamed styrene resin, flame retardant foamed styrene resin composition, and extrusion foamed molded body thereof

Abstract

The present invention provides a flame retardant composition for foamed styrene resin, which can be used to produce a foamed molded body having excellent flame retardancy and heat resistance, a flame-retardant foamed styrene resin composition, and an extrusion-foamed molded body thereof. The flame retardant composition for foamed styrene resin of the present invention contains at least component (B1) tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), component (C) zinc fatty acid, and component (D) fatty acid metal salt (except for the (C) component), the content of the (C) component is 0.1 to 15 parts by mass per 100 parts by mass of the (B1) component, and the content of the (D) component is 1 to 35 parts by mass per 100 parts by mass of the (B1) component.

Description

Technical Field

[0001] This invention relates to flame retardant compositions for expanded polystyrene resins, flame retardant expanded polystyrene resin compositions, and extruded foamed articles thereof. Background Technology

[0002] Styrene-based resin foams are lightweight and therefore widely used in various fields, including insulation applications in household appliances and building materials, civil engineering applications such as embankment construction, and more. Because styrene-based resins are composed solely of carbon and hydrogen, they produce black smoke and burn intensely when ignited. Therefore, flame retardants are needed to make the resin flame-retardant depending on its intended use.

[0003] Previously, hexabromocyclododecane (HBCD) was known to be used as a flame retardant in the flame retardant treatment of styrene-based resin foams produced by extrusion, achieving the desired flame retardant effect with a relatively small amount. However, HBCD has low thermal stability; if the resin composition containing it is heated above its melting point, the HBr generated by the decomposition of HBCD will discolor the resin and degrade its quality. Furthermore, it can also cause corrosion problems in manufacturing equipment. In addition, it is ideal to reuse the waste from foam production and the waste generated during foam manufacturing as raw materials for the production of new foams. When the waste contains a flame retardant with low thermal stability such as HBCD, discoloration or depolymerization is promoted during the melting of the waste. Therefore, foams containing HBCD present a problem of difficulty in recycling.

[0004] From this perspective, research is currently underway on using other brominated flame retardants in extruded expanded styrene resin foams to replace HBCD. Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) has been proposed as one such brominated flame retardant. This flame retardant exhibits flame retardant effects comparable to HBCD, but to further improve thermal stability, it has been proposed to combine it with other flame retardants, such as tetrabromobisphenol A-bis(2,3-dibromopropyl ether) and tris(2,3-dibromopropyl) isocyanurate. Thus, while maintaining excellent flame retardant effects, the decomposition of the flame retardant is also inhibited, reducing the likelihood of resin degradation (see, for example, Patent Documents 1-3).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-275528

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-107227

[0009] Patent Document 3: Japanese Patent Application Publication No. 2012-136674 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] However, since flame retardancy and heat resistance are in a trade-off relationship, it is difficult to improve both properties simultaneously. In recent years, various applications using styrene-based foamed compounds have demanded further improvements in both flame retardancy and heat resistance. From this perspective, developing flame retardants to further improve the flame retardancy and heat resistance of foamed compounds, or developing resin compositions for manufacturing styrene-based resin foams, has become an urgent priority.

[0012] The present invention was made in view of the above circumstances, and its object is to provide a flame retardant composition for foamed styrene resin, a flame retardant foamed styrene resin composition, and an extruded foamed article thereof that can be used to manufacture foamed molded articles with excellent flame retardancy and heat resistance.

[0013] Technical means for solving problems

[0014] In order to achieve the above objectives, the inventors have conducted repeated and in-depth research and found that by combining specific flame retardants, zinc fatty acids and the metal salt of the fatty acids, the above objectives can be achieved, thus completing the present invention.

[0015] That is, the present invention includes, for example, the subject matter described in the following items.

[0016] Item 1

[0017] A flame retardant composition for expanded polystyrene resin, comprising at least the following components (B1), (C), and (D),

[0018] (B1) Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether),

[0019] (C) Zinc fatty acids, and

[0020] (D) Fatty acid metal salts (excluding component (C) above),

[0021] The content of component (C) is 0.1 to 15 parts by mass relative to every 100 parts by mass of component (B1).

[0022] The content of the above component (D) is 1 to 35 parts by mass relative to every 100 parts by mass of the above component (B1).

[0023] Item 2

[0024] The flame retardant composition for expanded styrene resin as described in item 1, wherein, in addition to the aforementioned component (B1), component (B2) is also contained as a flame retardant.

[0025] The above-mentioned component (B2) is a bromine-containing flame retardant.

[0026] Item 3

[0027] The flame retardant composition for expanded styrene resin as described in claim 1 or 2, wherein the component (B2) comprises at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine and brominated epoxy oligomers.

[0028] Item 4

[0029] The flame retardant composition for expanded styrene resin as described in item 2 or 3, wherein the content of component (B1) is 10% to 99% by mass relative to the total amount of the above components (B1) and (B2).

[0030] Item 5

[0031] A flame-retardant expanded styrene resin composition comprising, as described in any one of items 1 to 4, a flame retardant composition for expanded styrene resin, and component (A) a styrene resin.

[0032] Item 6

[0033] An extruded foamed article of a flame-retardant foamed styrene resin composition, wherein the flame-retardant foamed styrene resin composition is the flame-retardant foamed styrene resin composition described in item 5.

[0034] Invention Effects

[0035] By using the flame retardant composition for expanded polystyrene resin of the present invention, extruded foamed articles with excellent flame retardancy and heat resistance can be manufactured. Furthermore, extruded foamed articles obtained using flame-retardant expanded polystyrene resin compositions containing the flame retardant composition for expanded polystyrene resin exhibit excellent flame retardancy and heat resistance. Detailed Implementation

[0036] The embodiments of the present invention will now be described in detail. Furthermore, in this specification, the expressions "containing" and "comprising" include concepts such as "containing," "comprising," "substantially comprising," and "only comprising."

[0037] 1. Flame retardant composition for expanded polystyrene resin

[0038] The flame retardant composition for expanded styrene resin of the present invention comprises at least the following components (B1), (C) and (D).

[0039] (B1) Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether),

[0040] (C) Zinc fatty acids, and

[0041] (D) Fatty acid metal salts (excluding component (C) above).

[0042] In particular, in the flame retardant composition for foamed styrene resin of the present invention, the content of component (C) is 0.1 to 15 parts by mass relative to 100 parts by mass of component (B1), and the content of component (D) is 1 to 35 parts by mass relative to 100 parts by mass of component (B1).

[0043] By incorporating the flame retardant composition for foamed styrene resin of the present invention into styrene resin as a flame retardant, it is possible to manufacture extruded foamed molded articles with excellent flame retardancy and heat resistance.

[0044] Hereinafter, the flame retardant composition for foamed styrene resin of the present invention will be simply referred to as "flame retardant composition", the flame retardant foamed styrene resin composition containing the flame retardant composition for foamed styrene resin of the present invention will be simply referred to as "styrene resin composition", and the extruded foamed articles obtained using the styrene resin composition will be simply referred to as "foamed articles".

[0045] <Ingredient (B1)>

[0046] The flame retardant composition contains component (B1) which is tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), and it is the component that functions as a flame retardant. That is, component (B1) is a brominated flame retardant.

[0047] Ingredient (B1) can be prepared using known methods, or it can be obtained from commercially available products.

[0048] <Other Flame Retardants>

[0049] The flame retardant composition may also contain flame retardants other than component (B1) as long as it does not impair the effects of the present invention. In this case, flame retardancy and heat resistance may sometimes be improved. Brominated flame retardants other than component (B1) can be listed as examples. Hereinafter, such brominated flame retardants will be simply referred to as "component (B2)".

[0050] Examples of components (B2) include: tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine, tetrabromobisphenol S-bis(2,3-dibromopropyl ether), tetrabromobisphenol F-bis(2,3-dibromopropyl ether), tetrabromobisphenol A, hexabromobenzene, pentabromotoluene, polybrominated diphenyl ethers, polybrominated diphenyl ethane, bis(polybrominated phenoxy ethane), polybrominated phenyl indenium, polypentabromobenzyl acrylate, ethylene bis(tetrabromophthalimide), tris(tribromoneopentyl)phosphate, brominated epoxy oligomers, etc. Component (B2) can be a single component or two or more components.

[0051] From the viewpoint of easily improving the flame retardancy and heat resistance of the foamed molded body of the flame retardant composition, component (B2) preferably includes at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine and brominated epoxy oligomers.

[0052] When the flame retardant composition comprises both component (B1) and component (B2), the proportion of each is not particularly limited. For example, considering that the flame retardant composition readily imparts excellent flame retardancy, the proportion of component (B1) is preferably set to 10% to 99% by mass relative to the total amount of components (B1) and (B2). The proportion of component (B1) is preferably 20% by mass or more, more preferably 30% by mass or more, further preferably 35% by mass or more, and particularly preferably 40% by mass or more, relative to the total amount of components (B1) and (B2). Furthermore, the proportion of component (B1) is preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and particularly preferably 60% by mass or less, relative to the total amount of components (B1) and (B2).

[0053] The flame retardant composition may contain flame retardants other than components (B1) and (B2), such as a wide range of well-known flame retardants. When the flame retardant composition contains flame retardants other than components (B1) and (B2), their proportion is not particularly limited and can be appropriately adjusted within a range that does not impair the effects of the present invention. From the viewpoint of not significantly increasing costs, the proportion of the flame retardant relative to the total mass of components (B1) and (B2) may be set to 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less. The flame retardant contained in the flame retardant composition may be only components (B1) and (B2).

[0054] <Ingredient (C)>

[0055] The component (C) contained in the flame retardant composition is zinc fatty acid. By including zinc fatty acid in the flame retardant composition, the flame retardant composition can impart excellent flame retardancy and heat resistance to extruded foamed articles, and in particular, can improve flame retardant performance.

[0056] In zinc fatty acids, the fatty acid portion (the portion of zinc fatty acids other than zinc) can be either saturated or unsaturated zinc fatty acids, and can be either linear or branched. From the perspective of easily improving flame retardancy and heat resistance, linear saturated zinc fatty acids and linear unsaturated zinc fatty acids are preferred.

[0057] In zinc fatty acids, the number of carbon atoms (including carboxyl carbon) in the fatty acid portion is not particularly limited. From the perspective of easily improving flame retardancy and heat resistance, the number of carbon atoms in the fatty acid portion is preferably 2 or more, more preferably 8 or more, further preferably 10 or more, particularly preferably 12 or more, and preferably 40 or less, more preferably 35 or less, further preferably 30 or less, and particularly preferably 25 or less.

[0058] In zinc fatty acids, one or more substituents may be present at the fatty acid site. Examples of such substituents include hydroxyl, carboxyl, halogen, and amino groups. When one or more substituents are present at the fatty acid site, hydroxyl groups are preferred. Furthermore, when one or more substituents are present at the fatty acid site, the number of substituents is, for example, one to five, preferably one to three.

[0059] Examples of zinc fatty acids include zinc acetate, zinc propionate, zinc octanoate, zinc docosate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc 12-hydroxystearate, zinc lignite, and zinc oleate.

[0060] The flame retardant composition may contain only one component (C) (zinc fatty acid) or two or more components. Component (C) may be prepared by known methods or obtained from commercially available products.

[0061] As described above, in the flame retardant composition, the content of component (C) is 0.1 to 15 parts by weight relative to every 100 parts by weight of component (B1). That is, in the flame retardant composition,

[0062] {mass of component (C) / mass of component (B1)} × 100

[0063] The value ranges from 0.1 to 15. Based on this, the flame retardant effect of component (B1) can be improved, and it can exhibit excellent flame retardant properties.

[0064] The content of component (C) is preferably 0.15 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 0.3 parts by mass or more, and particularly preferably 0.4 parts by mass or more, relative to 100 parts by mass of component (B1). Furthermore, the content of component (C) is preferably 12 parts by mass or less, more preferably 10 parts by mass or less, further preferably 7 parts by mass or less, and particularly preferably 4.5 parts by mass or less, relative to 100 parts by mass of component (B1). The most preferably content of component (C) is 0.4 to 4.5 parts by mass per 100 parts by mass of component (B1), in which case the flame retardant composition can improve both flame retardancy and heat resistance.

[0065] <Ingredient (D)>

[0066] The flame retardant composition contains component (D), which is a fatty acid metal salt. This fatty acid metal salt (D) refers to components other than zinc (as described in component (C)). In summary, in component (D), the metal in the fatty acid metal salt is a component other than zinc.

[0067] By including component (D) in the flame retardant composition, the flame retardant properties can be further improved. In addition, the extruded foamed molded article can be endowed with excellent heat resistance, and an extruded foamed molded article with excellent formability can be obtained.

[0068] In fatty acid metal salts, the fatty acid portion (the portion other than the metal in the fatty acid metal salt) can be either saturated zinc fatty acid or unsaturated zinc fatty acid, and can also be either linear or branched. From the perspective of easily improving flame retardancy and heat resistance, linear saturated fatty acid metal salts and linear unsaturated fatty acid metal salts are preferred.

[0069] In fatty acid metal salts, the number of carbon atoms (including carboxyl carbon) in the fatty acid site is not particularly limited. From the perspective of easily improving flame retardancy and heat resistance, the number of carbon atoms in the fatty acid site of the fatty acid metal salt is preferably 2 or more, more preferably 8 or more, further preferably 10 or more, particularly preferably 12 or more, and preferably 40 or less, more preferably 35 or less, further preferably 30 or less, and particularly preferably 25 or less.

[0070] In fatty acid metal salts, one or more substituents may be present at the fatty acid site. Examples of such substituents include hydroxyl, carboxyl, halogen, and amino groups. When one or more substituents are present at the fatty acid site, hydroxyl groups are preferred. Furthermore, when one or more substituents are present at the fatty acid site, the number of substituents is, for example, one to five, preferably one to three.

[0071] In fatty acid metal salts, there are no particular restrictions on the type of metal as long as it is not zinc. Examples include lithium, magnesium, calcium, aluminum, barium, and sodium.

[0072] Examples of metal salts of fatty acids include: acetic acid, propionic acid, octanoic acid, docosanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, linalic acid, and oleic acid, etc. (the metals are lithium, magnesium, calcium, aluminum, barium, or sodium).

[0073] The flame retardant composition may contain a single component (D) (a fatty acid metal salt) or two or more components. Component (D) may be prepared by known methods or obtained from commercially available products.

[0074] As described above, in the flame retardant composition, the content of component (D) is 1 to 35 parts by mass relative to every 100 parts by mass of component (B1). That is, in the flame retardant composition,

[0075] {mass of component (D) / mass of component (B1)} × 100

[0076] The value ranges from 1 to 35. Based on this, the flame retardant properties can be further improved. In addition, the extruded foamed molded articles can be endowed with excellent heat resistance, thereby obtaining extruded foamed molded articles with excellent formability.

[0077] The content of component (D) is preferably 2 parts by mass or more, more preferably 2.5 parts by mass or more, further preferably 3 parts by mass or more, and particularly preferably 4 parts by mass or more, relative to 100 parts by mass of component (B1). Furthermore, the content of component (D) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 17 parts by mass or less, relative to 100 parts by mass of component (B1). The content of component (C) is most preferably 4 to 17 parts by mass relative to 100 parts by mass of component (B1), in which case the flame retardant composition can significantly improve both flame retardancy and heat resistance.

[0078] In the flame retardant composition, by combining the above-mentioned components (C) and (D) as constituent components, it is possible to improve both flame retardancy and heat resistance, which are difficult to balance in the prior art. By keeping these contents within a specific range, both flame retardancy and heat resistance can be significantly improved, and the formability of the extruded foamed molded article is not easily damaged.

[0079] <Ingredient (E)>

[0080] In addition to components (A) to (D), the flame retardant composition may also include a heat stabilizer as component (E). Alternatively, the flame retardant composition may not contain component (E), but rather the styrene-based resin composition described later may include component (E). The heat stabilizer can further improve the thermal stability of the foamed molded article.

[0081] There is no particular limitation on the types of heat stabilizers; for example, a wide range of well-known heat stabilizers that can be used in foamed molded articles can be listed. Examples of heat stabilizers include: sulfide compounds, hindered phenolic compounds, hindered amine compounds, organotin compounds, phosphate esters, and hydrotalcite.

[0082] Examples of thioether compounds include: dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearate-3,3'-thiodipropionate, pentaerythritol tetra(3-lauryl thiopropionate), di-tetrazyl-3,3'-thiodipropionate, 2-mercaptobenzimidazole, etc.

[0083] Examples of hindered phenolic compounds include: 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], glyceryl tris[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Butyl-4-hydroxyphenyl)propionate, thiodiethylidene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecanyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, diethylbis[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate [1-Dimethylethyl]-4-hydroxyphenyl]methyl]phosphonate calcium, 3,3',3”,5,5',5”-hexa-tert-butyl-a,a',a”-(trimethylbenzene-2,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] Examples of such products include 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-dimethyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-ylamino)phenol.

[0084] Examples of hindered amine compounds include: 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl-2-n-butylmalonate), tetra(2,2,6,6-tetramethyl-4-piperidinyl-1,2,3,4-butanetetracarboxylate, tetra(1,2,2,6,6-pentamethyl-4-piperidinyl)-1,2,3,4-butanetetracarboxylate, etc.

[0085] Examples of organotin compounds include dioctyltin dilaurate and dioctyltin maleate.

[0086] Phosphate esters as component (E) can be exemplified by phosphite compounds. Examples of such phosphite compounds include trimethyl phosphite, triethyl phosphite, tributyl phosphite, tri(2-ethylhexyl) phosphite, tristearyl phosphite, and other trialkyl phosphites. Additionally, examples include alkylallyl phosphites such as 2-ethylhexyl diphenyl phosphite and isodecyl diphenyl phosphite, tri(2,4-di-tert-butylphenyl) phosphite, trinonylphenyl phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl phosphite, tetra(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-dimethylbisphosphite, and bis(nonylphenyl) Pentaerythritol diphosphite, bis-stearyl pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2'-methylene bis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphite, tetra(tetrazyl)-4,4'-butylidene-bis(2-tert-butyl-5-methylphenyl) diphosphite, hexa-tetrazyl-1,1,3-tris(3-tert-butyl-6-methyl-4-oxyphenyl)-3-methylpropane triphosphite, mono(dinonylphenyl)mono-p-nonylphenyl phosphite, tris(monononylphenyl) phosphite, tetraalkyl(C=12-16)-4,4'-isopropylidene-(bisphenyl) diphosphite.

[0087] In the flame retardant composition, the content of component (E) is not particularly limited, and can be set to an appropriate amount within a range that does not hinder the effect of the present invention. For example, the content of component (E) is 0.1% to 50% by mass relative to the total mass of component (B1), preferably 1% to 30% by mass.

[0088] <Ingredients (F)>

[0089] In addition to components (A) to (D), the flame retardant composition may also include a flame retardant reinforcing agent as component (F). Alternatively, the flame retardant composition may not contain component (F), but rather the styrene-based resin composition described later may contain component (F). The flame retardant reinforcing agent can further improve the thermal stability of the foamed molded article.

[0090] There is no particular limitation on the types of flame retardant reinforcing agents; for example, well-known flame retardant reinforcing agents that can be used in foamed molded articles can be widely listed. Phosphate esters other than the aforementioned component (E) can be listed as examples of flame retardant reinforcing agents. Specific examples of such phosphate esters include: triphenyl phosphite, tricresyl phosphite, diphenyltoluene phosphite, diphenyldimethyl phosphite, resorcinol di-dimethylyl phosphite, and other phosphite compounds; and phosphate ester compounds such as triphenyl phosphate, tri-dimethyl phosphate, and tricresyl phosphate. Furthermore, examples of flame retardant reinforcing agents include cumene peroxide, cumene hydroperoxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxide)-hexyne-3, dicumene peroxide, and 2,3-dimethyl-2,3-diphenylbutane. In addition, other flame retardant reinforcing agents include: phthalocyanine iron, phthalocyanine manganese, phthalocyanine cobalt and other phthalocyanine metal complexes, zeolites, etc.

[0091] In the flame retardant composition, the content of component (F) is not particularly limited, and can be set to an appropriate amount within a range that does not hinder the effect of the present invention. For example, the content of component (F) is 0.1% to 15% by mass relative to the total mass of component (B1), preferably 1% to 10% by mass.

[0092] <Component (H)>

[0093] In addition to components (A) to (D), the flame retardant composition may also include a foaming nucleating agent as component (H). Alternatively, the flame retardant composition may not contain component (H), but rather the styrene-based resin composition described later may include component (H). The foaming nucleating agent readily forms bubbles in the foamed molded article of the styrene-based resin composition, and the bubble diameter is easily adjusted, thus facilitating the adjustment of the strength, etc., of the foamed molded article.

[0094] There is no particular limitation on the types of foaming nucleating agents; for example, a wide range of well-known foaming nucleating agents that can be used in foamed molded articles can be listed. Examples of foaming nucleating agents include inorganic materials such as talc, bentonite, kaolin, mica, silica, clay, and diatomaceous earth.

[0095] <Other Ingredients>

[0096] In addition to the components described above, the flame retardant composition may also contain various other components without impairing the effects of the present invention. When the flame retardant composition contains other components, their proportions are not particularly limited; for example, relative to the total mass of (B1), component (C), and component (D), they may be set to 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 1% by mass or less.

[0097] There are no particular limitations on the preparation method of the flame retardant composition; for example, it can be the same as the preparation method of known flame retardant compositions.

[0098] 2. Flame-retardant expanded styrene resin composition

[0099] The flame-retardant expanded styrene resin composition (styrene resin composition) of the present invention, in addition to comprising the above-described flame retardant composition, also comprises component (A) styrene resin. That is, the flame retardant composition for expanded styrene resin of the present invention comprises component (A), component (B1), component (C), and component (D).

[0100] Includes: (A) styrene-based resins

[0101] (B1) Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether)

[0102] (C) Zinc fatty acids, and

[0103] (D) Fatty acid metal salts (excluding component (C) above).

[0104] This is merely a precautionary note; the content of component (C) is 0.1 to 15 parts by mass relative to 100 parts by mass of component (B1), and the content of component (D) is 1 to 35 parts by mass relative to 100 parts by mass of component (B1).

[0105] The styrene-based resin composition of the present invention forms a foam by melting it in an extruder, pressing a foaming agent into the melt, and extruding it. This foam exhibits excellent flame retardancy and heat resistance. In other words, the styrene-based resin composition according to the present invention can manufacture extruded foamed articles with excellent flame retardancy and heat resistance.

[0106] Component (A) contained in the styrene-based resin composition is a styrene-based resin. This styrene-based resin is the main component of the styrene-based resin composition, that is, it is the main component in the foamed molded article.

[0107] There are no particular limitations on the types of styrene-based resins; for example, well-known styrene-based resins used for foam molding can be widely used.

[0108] Examples of styrene-based resins include homopolymers of styrene monomers and copolymers of styrene with other monomers. Other monomers include, for example, p-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, 1,1-diphenylethylene, p-(N,N-diethylaminoethyl)styrene, and p-(N,N-diethylaminomethyl)styrene, etc. Other monomers may be a single type or a combination of two or more.

[0109] The monomer units constituting the styrene-based resin may contain 50% by mass or more of styrene monomer, preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. The styrene-based resin may be a homopolymer of polystyrene.

[0110] The styrene-based resin may contain other components as long as they do not impede the effects of the present invention. Other components may include, for example, rubber-like polymers. Examples of rubber-like polymers include: polybutadiene, polyisoprene, styrene-butadiene copolymer, styrene-isoprene copolymer, acrylonitrile-butadiene copolymer, styrene-isobutylene-butadiene copolymer, butadiene-(meth)acrylate copolymer, styrene-butadiene block copolymer, styrene-isoprene block copolymer, butyl rubber, ethylene-α-olefin copolymer (ethylene-propylene rubber), ethylene-α-olefin-polyene copolymer (ethylene-propylene-diene rubber), silicone rubber, acrylic rubber, hydrogenated diene rubber (hydrogenated styrene-butadiene block copolymer, hydrogenated butadiene polymer, etc.), etc.

[0111] The rubbery polymer contained in the styrene-based resin may be one or more types. When the styrene-based resin composition contains a rubbery polymer, the proportion of the rubbery polymer relative to the monomer components constituting the styrene-based resin is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0112] There are no particular limitations on the molecular weight of styrene-based resins. The molecular weight can be adjusted to an appropriate range within the range that allows for foaming, depending on the intended use. For example, it can be set to the same range as known foamed molded articles.

[0113] The styrene-based resin may also contain other additives, provided that they do not impair the effects of the present invention. Examples of such additives include: light stabilizers, antioxidants, preservatives, surfactants, fillers such as inorganic particles, pigments, colorants, and fungicides. One or more of these additives may be included in the styrene-based resin. When the styrene-based resin contains other additives, their content relative to the total mass of the styrene-based resin is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0114] There are no particular limitations on the manufacturing method of styrene-based resins. For example, styrene-based resins as component (A) can be obtained by using known methods. Alternatively, styrene-based resins can be obtained, for example, from commercially available products.

[0115] The content of component (B1) in the styrene-based resin composition is not particularly limited. From the viewpoint of easily improving flame retardancy and heat resistance, the content of component (B1) relative to 100 parts by weight of the aforementioned styrene-based resin can be, for example, 0.05 parts by weight or more, preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, even more preferably 0.9 parts by weight or more, and particularly preferably 1 part by weight or more. Furthermore, from the viewpoint of easily improving flame retardancy and heat resistance, the content of component (B1) in the styrene-based resin composition relative to 100 parts by weight of the aforementioned styrene-based resin can be 20 parts by weight or less, preferably 18 parts by weight or less, more preferably 10 parts by weight or less, even more preferably 5 parts by weight or less, even more preferably 4 parts by weight or less, and particularly preferably 3 parts by weight or less.

[0116] When a styrene-based resin composition comprises both component (B1) and component (B2), from the viewpoint of easily improving the flame retardancy and heat resistance of the foamed molded article of the styrene-based resin composition, the total mass of component (B1) and component (B2) is preferably 0.1 parts by mass and 20 parts by mass or less per 100 parts by mass of styrene-based resin. The total mass of component (B1) and component (B2) is preferably 1 part by mass or more per 100 parts by mass of styrene-based resin, more preferably 1.5 parts by mass or more, further preferably 2 parts by mass or more, and particularly preferably 2.5 parts by mass or more. Furthermore, the total amount of component (B1) and component (B2) is preferably 10 parts by mass or less per 100 parts by mass of the aforementioned styrene-based resin, more preferably 9 parts by mass or less, further preferably 8 parts by mass or less, and particularly preferably 6 parts by mass or less.

[0117] In styrene-based resin compositions, the content of component (C) is not particularly limited. For example, from the viewpoint of easily improving flame retardancy and heat resistance, the content of component (C) relative to 100 parts by weight of the above-mentioned styrene-based resin can be set to 0.001 parts by weight or more, preferably 0.002 parts by weight or more, more preferably 0.005 parts by weight or more, further preferably 0.01 parts by weight or more, and particularly preferably 0.02 parts by weight or more. Furthermore, from the viewpoint of easily improving flame retardancy and heat resistance, the content of component (C) relative to 100 parts by weight of the above-mentioned styrene-based resin can be set to 5 parts by weight or less, preferably 1 part by weight or less, more preferably 0.8 parts by weight or less, further preferably 0.5 parts by weight or less, and particularly preferably 0.3 parts by weight or less.

[0118] In styrene-based resin compositions, the content of component (D) is not particularly limited. For example, from the viewpoint of easily improving flame retardancy and heat resistance, in styrene-based resin compositions, the content of component (D) relative to 100 parts by weight of the aforementioned styrene-based resin is preferably 0.01 parts by weight or more, more preferably 0.02 parts by weight or more, even more preferably 0.03 parts by weight or more, and particularly preferably 0.04 parts by weight or more. Furthermore, relative to 100 parts by weight of the aforementioned styrene-based resin, the content of component (D) may be 5 parts by weight or less, preferably 3 parts by weight or less, more preferably 1 part by weight or less, even more preferably 0.8 parts by weight or less, and particularly preferably 0.5 parts by weight or less.

[0119] When component (E) is included in a styrene-based resin composition, its content is not particularly limited. For example, from the viewpoint of easily improving the thermal stability of the foamed molded article, the content of component (E) relative to 100 parts by mass of the aforementioned styrene-based resin can be set to 0.001 parts by mass or more, preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, and even more preferably 0.03 parts by mass or more. In addition, from the viewpoint of easily improving the thermal stability of the foamed molded article, the content of component (E) relative to 100 parts by mass of the aforementioned styrene-based resin is preferably 1 part by mass or less, more preferably 0.8 parts by mass or less, even more preferably 0.6 parts by mass or less, and particularly preferably 0.4 parts by mass or less.

[0120] When component (F) is included in a styrene-based resin composition, its content is not particularly limited. For example, from the viewpoint of easily improving the flame retardancy of the foamed molded article, the content of component (F) is preferably set to 0.01 parts by mass or more and 0.5 parts by mass or less per 100 parts by mass of the above-mentioned styrene-based resin.

[0121] When a styrene-based resin composition contains component (H), its content is not particularly limited. For example, the content of component (H) may be 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the aforementioned styrene-based resin.

[0122] In addition to the components described above, the styrene-based resin composition may also contain various other components. For example, it may contain a foaming agent as component (G) described later. The foaming agent may be incorporated into the styrene-based resin composition during the foaming step described later, or it may be incorporated into the styrene-based resin composition before foaming.

[0123] Furthermore, without impairing the effects of the present invention, the styrene-based resin composition may contain various additives. Examples of additives include, for instance, light stabilizers, ultraviolet absorbers, ultraviolet stabilizers, heavy metal inert agents, impact modifiers, colorants, lubricants, anti-drip agents, crystal nucleating agents, antistatic agents, compatibility agents, and other known resin additives. When the styrene-based resin composition contains additives, for example, the proportion relative to the mass of the styrene-based resin may be 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less.

[0124] There are no particular limitations on the preparation method of the styrene-based resin composition. For example, it can be set to be the same as the preparation method of the known styrene-based resin composition for foaming. For example, the styrene-based resin composition can be prepared by mixing the flame retardant composition, component (A), and one or more other components added as needed in a specified mixing ratio.

[0125] Styrene-based resin compositions can be formed into foamed articles by various foaming methods. For example, an extruded foamed article of a styrene-based resin composition can be obtained by extruding and foaming the styrene-based resin composition.

[0126] There are no particular limitations on the method for manufacturing extruded foamed articles; for example, well-known manufacturing methods can be widely used. For instance, extruded foamed articles can be manufactured by a manufacturing method that includes the following extrusion foaming steps.

[0127] Extrusion foaming process: The styrene-based resin composition is melt-mixed in an extruder, the foaming agent (G) as component (G) is pressed into the extruder, and then extruded from the extruder die into the atmosphere.

[0128] The above-described extrusion foaming process is used to foam styrene-based resin to obtain an extruded foamed styrene-based resin composition.

[0129] In the extrusion foaming process, components (A), (B1), (C), and (D) can be supplied to the extruder in any order and melt-mixed within the extruder for foaming and molding. Alternatively, some or all of the components can be pre-mixed to form a mixture, which is then supplied to the extruder.

[0130] As foaming agents, well-known foaming agents used in foam molding can be widely used. Specifically, examples include: volatile organic foaming agents such as propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, 1-chloro-1,1-difluoroethane, monochlorodifluoromethane, monochloro-1,2,2,2-tetrafluoroethane, 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,3,3,3-pentafluoropropane, dichloromethane, 1,2-dichloroethane, dimethyl ether, diethyl ether, and ethylmethyl ether; inorganic foaming agents such as water, nitrogen, and carbon dioxide; and chemical foaming agents such as azo compounds. Foaming agents can be used alone or in combination of two or more.

[0131] The amount of foaming agent can be appropriately set according to the desired properties of the foam and the molding method used. For example, relative to 100 parts by weight of styrene-based resin, the amount of foaming agent can be set to 0.01 parts by weight to 20 parts by weight, preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.5 parts by weight to 5 parts by weight.

[0132] The extruded foamed article of the styrene-based resin composition obtained as described above contains at least component (A), component (B1), component (C), and component (D), and the contents of component (C) and component (D) are within specific ranges. Based on this, the extruded foamed article exhibits excellent flame retardancy and heat resistance, as well as excellent formability. Therefore, the extruded foamed article can be used, for example, in various applications requiring high flame retardancy levels.

[0133] [Example]

[0134] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0135] The raw materials used in the examples and comparative examples are as follows.

[0136] <Ingredients (A)>

[0137] (A) Styrene-based resins

[0138] • GP-PS (PSJ polystyrene G9305 manufactured by PS Japan)

[0139] <Ingredient (B1)>

[0140] Tetrabromobisphenol A - bis(2,3-dibromo-2-methylpropyl ether) ("Pyroguard SR-130" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.)

[0141] <Ingredient (B2)>

[0142] • B2-1: Tetrabromobisphenol A-bis(2,3-dibromopropyl ether) ("Pyroguard SR-720N" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.)

[0143] • B2-2: Tris(2,3-dibromopropyl)isocyanurate ("Pyroguard SR-750" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.)

[0144] • B2-3: Tris(tribromophenoxy)triazine ("Pyroguard SR-245" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.)

[0145] • B2-4: Brominated epoxy oligomer (SR-T1000 manufactured by Sakamoto Pharmaceutical Co., Ltd.)

[0146] <Ingredient (C)>

[0147] (C) Zinc fatty acids

[0148] • C-1: Zinc stearate ("Zn-St" manufactured by Nitto Kasei Corporation)

[0149] • C-2: Zinc 12-hydroxystearate (“ZS-6” manufactured by Nitto Kasei Corporation)

[0150] • C-3: Zinc lignite ("ZS-8" manufactured by Nitto Kasei Corporation)

[0151] C-4: Zinc oleate

[0152] • C-5: Zinc laurate (“ZS-3” manufactured by Nitto Kasei Corporation)

[0153] <Ingredient (D)>

[0154] (D) Fatty acid metal salts

[0155] • D-1: Calcium stearate ("Ca-St" manufactured by Nitto Kasei Corporation)

[0156] • D-2: Magnesium stearate ("Mg-St" manufactured by Nitto Kasei Corporation)

[0157] • D-3: Aluminum stearate (“Al-St” manufactured by Nitto Kasei Corporation)

[0158] • D-4: Lithium stearate (“LI-ST” manufactured by Nitto Kasei Corporation)

[0159] • D-5: Sodium stearate ("NA-ST" manufactured by Nitto Kasei Corporation)

[0160] • D-6: Calcium 12-hydroxystearate (CS-6 manufactured by Nitto Kasei Corporation)

[0161] • D-7: Calcium Laurate ("CS-3" manufactured by Nitto Kasei Corporation)

[0162] D-8: Magnesium Laurate

[0163] • D-9: Calcium lignite ("CS-8" manufactured by Nitto Kasei Corporation)

[0164] • D-10: Magnesium lignite (MS-8 manufactured by Nitto Kasei Corporation)

[0165] <Ingredient (E)>

[0166] (E) Heat stabilizer

[0167] Bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (Adekastab PEP-36 manufactured by ADEKA)

[0168] <Ingredients (F)>

[0169] (F) Flame retardant reinforcing agent

[0170] F-1: 2,3-Dimethyl-2,3-diphenylbutane (Nofmer BC-90 manufactured by Nippon Oil Company)

[0171] F-2: Triphenyl phosphate (TPP manufactured by Daihachi Chemical Industry Co., Ltd.)

[0172] <Ingredients (G)>

[0173] (G) Foaming agent

[0174] ·G-1: Isobutane

[0175] G-2: Dimethyl ether

[0176] <Component (H)>

[0177] (H) Foaming nucleating agent

[0178] Talc MS (manufactured by Talc Industries, Ltd., Japan)

[0179] (Example 1)

[0180] The components, excluding the foaming agent, were added to a 65mm diameter extruder according to the mixing ratios shown in Table 1 below. The extruder was heated to 200°C to melt and plasticize the components, and the mixture was further kneaded to prepare a styrene-based resin composition within the extruder. A two-stage extruder, consisting of a 65mm diameter and a 90mm diameter, was used. The mixing amounts of each component are shown in Table 1. Component (A) was set at 100 parts by mass, component (B1) at 0.9 parts by mass, component (B2) B2-1 at 2.1 parts by mass, component (C) C-1 at 0.03 parts by mass, component (D) D-1 at 0.1 parts by mass, and component (E) at 0.05 parts by mass.

[0181] Next, a specified amount of foaming agent is forced into the front end of a 65mm extruder (opposite to the die of a 90mm extruder) using another production line, and the resin temperature (internal temperature) is cooled to 120°C using the 90mm extruder. As shown in Table 1, for the foaming agent as component (G), G-1 is set at 3 parts by mass, and G-2 is set at 3 parts by mass (relative to 100 parts by mass of styrene-based resin). Subsequently, the resin composition is extruded into the atmosphere through a die lip with a rectangular cross-section of 2.5mm in the thickness direction and 45mm in the width direction, located at the front end of the 90mm extruder, thereby obtaining a cuboid-shaped extruded foamed styrene-based resin.

[0182] (Examples 2 to 36)

[0183] The types and amounts of each component were changed as shown in Tables 1 and 2. Otherwise, the extruded foamed molded articles were obtained by the same method as in Example 1.

[0184] (Comparative Examples 1 to 8)

[0185] The types and amounts of each component were changed as shown in Table 3 below. Otherwise, the extruded foamed article was obtained by the same method as in Example 1.

[0186] (Evaluation Method)

[0187] <Flame retardancy>

[0188] The oxygen index was determined according to JIS (Japanese Industrial Standards) K-7201, and the flame retardant performance was evaluated based on the following criteria.

[0189] ◎: With an oxygen index of 26.5 or higher, it has exceptionally good flame retardancy.

[0190] 〇: With an oxygen index of 26.0 or higher and less than 26.5, it has excellent flame retardancy.

[0191] ×: Oxygen index less than 26.0, does not have excellent flame retardancy.

[0192] <Heat resistance>

[0193] The heat resistance of the foamed molded articles was evaluated based on the degree of yellowing (YI: Yellow Index) of the foamed articles obtained in each embodiment and comparative example. Specifically, the extruded foamed articles in the test were sliced ​​into plates using a cutter, compressed with biaxial rollers, and then pulverized using a pulverizer. The pulverized material was fed into a torque rheometer (Labo Plastomill) and melt-mixed at 200°C, then quickly removed and shaped into 3.2 mm thick plates using a cooling press. The resulting plate-shaped articles were heated in a hot press at 220°C for 40 minutes, and then cooled using a cooling press. The cooled plate-shaped articles were dissolved in dichloromethane to a concentration of 10% by mass, and the solution was filtered through a 0.45 μm filter as the heat resistance test sample. The YI value of the sample was determined using a spectrophotometer (SE-6000 manufactured by Nippon Denshoku Kogyo Co., Ltd.) by transmission method, and the heat resistance performance was evaluated based on the following criteria.

[0194] ◎: With a YI value of less than 10, it has exceptionally good flame retardancy.

[0195] 〇: With a YI value greater than 10 and less than 15, it has excellent flame retardancy.

[0196] ×: If the YI value exceeds 15, it does not have excellent flame retardancy.

[0197] <Formability>

[0198] The formability of the foamed articles obtained in each embodiment and comparative example is evaluated based on the following criteria.

[0199] ○: No voids, protrusions, foreign objects, or discoloration were found on the surface of the foam; it was smooth and had a good appearance.

[0200] ×: The foam surface has at least one of the following: voids, protrusions, foreign objects, and discoloration; its smoothness and appearance are poor.

[0201] Tables 1 and 2 show the dosage (parts by mass) of each component used in each embodiment, and the evaluation results of the obtained foamed molded articles.

[0202] [Table 1]

[0203]

[0204] [Table 2]

[0205]

[0206] Table 3 shows the mixing ratios of each component used in each comparative example and the evaluation results of the obtained foamed molded articles. In addition, in Tables 1 to 3, "(C / B1)*100" and "(D / B1)*100" refer to the content of component (C) relative to 100 parts by mass of component (B1) and the content of component (D) relative to 100 parts by mass of component (B1), respectively.

[0207] [Table 3]

[0208]

[0209] As can be seen from Tables 1 and 2, the styrene-based resin extruded foams prepared in each embodiment exhibit excellent flame retardancy and heat resistance. Furthermore, the extruded foams obtained in each embodiment also demonstrate excellent formability. In contrast, the styrene-based resin extruded foams prepared in the comparative examples were not formed from compositions containing all components (A) to (D), and therefore could not satisfy both flame retardancy and heat resistance. In particular, a comparison between Comparative Examples 1 to 4 and the embodiments shows that, from the perspective of significantly improving the mutually balancing flame retardancy and heat resistance, it is important to include both components (C) and (D) in specified amounts.

Claims

1. A flame retardant composition for expanded styrene resin, characterized in that, It contains at least the following ingredients (B1), (C) and (D). (B1) Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether), (C) Zinc fatty acids, and (D) Fatty acid metal salts other than those in component (C). In addition to component (B1), it also contains component (B2) as a flame retardant. The component (B2) is a brominated flame retardant. The content of component (C) is 0.1 to 15 parts by weight relative to every 100 parts by weight of component (B1). The content of component (D) is 1 to 35 parts by mass relative to every 100 parts by mass of component (B1).

2. The flame retardant composition for expanded styrene resin as described in claim 1, characterized in that, The component (B2) comprises at least one selected from the group consisting of tetrabromobisphenol A-bis(2,3-dibromopropyl ether), tris(2,3-dibromopropyl)isocyanurate, tris(tribromophenoxy)triazine and brominated epoxy oligomers.

3. The flame retardant composition for expanded styrene resin as described in claim 1 or 2, characterized in that, The content of component (B1) is 10% to 99% by mass relative to the total amount of component (B1) and component (B2).

4. A flame-retardant expanded styrene resin composition, characterized in that, The composition comprises a flame retardant composition for foamed styrene resin according to any one of claims 1 to 3, and component (A) styrene-based resin.

5. An extruded foamed article of a flame-retardant foamed styrene-based resin composition, characterized in that, The flame-retardant expanded styrene resin composition is the flame-retardant expanded styrene resin composition according to claim 4.

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