JP2005330351A - Styrenic resin extrusion foaming product and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrenic resin extrusion foaming product which uses foaming agents having excellent environmental compatibility, has excellent greatly high flame retardancy and heat-insulating property, and further has more excellent heat resistance than those of conventional products. <P>SOLUTION: This styrenic resin extrusion foaming product prepared by thermally melting a styrenic resin, adding a foaming agent, and then extrusion-foaming the melted mixture is characterized by adding (a) 2 to 6 pts. wt. of a 3 to 5C saturated hydrocarbon, (b) 1 to 7 pts. wt. of a compound selected from the group consisting of methyl chloride, ethyl chloride, and dimethyl ether, and/or (c) 0.1 to 5 pts. wt. of a non-fluorinated foaming agent excluding the foaming agents (a) and (b) as foaming agents, (d) 0.1 to 10 pts. wt. of a halogenated flame retardant, and (e) 0.01 to 2 pts. wt. of a basic inorganic compound as flame retardants, and has a foam density of 20 to 50 kg/m<SP>3</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a styrene resin extruded foam excellent in environmental compatibility, heat insulation and flame retardancy, and further excellent in heat resistance, and a method for producing the same.

  A method of continuously producing a foam by melting a styrene resin with an extruder or the like, then adding a foaming agent, cooling it, and extruding it into a low pressure region is already known (for example, patents). Document 1, Patent Document 2), and a method using chlorofluorocarbons as a foaming agent are also known (for example, Patent Document 3, Patent Document 4).

  However, chlorofluorocarbons are desired to be replaced if possible from the viewpoint of protecting the ozone layer.

  Styrenic resin extruded foam using a foaming agent other than chlorofluorocarbons and a production method thereof, such as styrene, using propane, butane or a mixture thereof, or the hydrocarbon and methyl chloride, ethyl chloride or a mixture thereof as the foaming agent A resin extruded foam and a production method thereof are disclosed in Patent Document 5. Further, in Patent Document 5, in order to satisfy the flame retardancy specified in JIS A9511, 1 to 3% by weight of hexabromocyclododecane or tetrabromobisphenol A is used, and residual gas in the foam of propane and butane as blowing agents. It is disclosed that the amounts are adjusted to 3.5 wt% or less and 2.0 wt% or less, respectively.

However, in the foam without using the chlorofluorocarbons obtained in the invention described in Patent Document 5, in order to adjust the residual gas amount of propane and butane to the above amount, Processing such as limiting the amount of addition or storing for a long period of time until the foaming agent is reduced after the production of the foam is required, and there are further problems such as inferior production stability and productivity during extrusion foaming. Furthermore, in the amount of propane and butane in the foam obtained by the invention described in Patent Document 5 that does not use chlorofluorocarbons, a high degree of heat insulation, for example, three types of extruded polystyrene foam heat insulating plates defined in JIS A9511. It is difficult to obtain a foam having properties. According to the study by the present inventors, it is preferable to leave more saturated hydrocarbon compounds such as propane and butane in order to obtain a foam having high heat insulation properties. However, if the foam density is in the range of 20 to 40 kg / m ³ , 4.0% by weight or more for propane and 2.5% by weight or more for butanes with respect to the weight of the foam. It is preferable to leave it, and it is considered that it is particularly preferable to leave 3.0% by weight or more of butanes. However, when a large amount of relatively flammable compounds such as aliphatic hydrocarbons typified by propane and butane remain, as described above, hexabromocyclododecane and tetrabromobisphenol A are added in an amount of 1.0 to If only 3.0% by weight is used, the flame retardancy specified in JIS A9511 may not be satisfied. On the other hand, in order to improve the flame retardancy, it is conceivable to increase the amount of the flame retardant to be added, but it is difficult to obtain a stable flame retardancy simply by increasing the amount of addition. In particular, although the styrene resin itself, which is the basic material of the foam, is flame retardant, the tendency that it is easy to ignite hydrocarbons that volatilize from the foam during combustion and it is difficult to suppress combustion is still difficult to solve. Furthermore, an increase in the amount of the flame retardant tends to cause deterioration of foam moldability, and it tends to be difficult to obtain a molded product with satisfactory quality.

  In a system using saturated hydrocarbon as a foaming agent, a halogen-based flame retardant and a phosphate ester compound are included (Patent Document 6), or a halogen-based flame retardant and a halogen-containing phosphate ester compound are included ( Patent Document 7 and Patent Document 8) disclose that a styrene resin extruded foam that does not use any chlorofluorocarbons, has excellent environmental compatibility, and has excellent heat insulation performance and flame retardancy can be obtained. . However, in the styrene resin extruded foam obtained by the inventions described in Patent Documents 6 to 8, the foam can be obtained by containing a phosphoric ester compound having a plasticity or a halogen-containing phosphate ester compound. As shown in FIG.

  When a mixed system of a styrene polymer, a foaming agent, and a halogen-containing material is heated and gelled to produce an extruded flame retardant styrene resin cell molded article, an alkaline earth metal oxide is added to the system. Patent Document 9 describes a method for producing a flame-retardant styrene-based resin cell molded product without coloring. However, Patent Document 9 aims to extrude foams that do not color the molded product, and is excellent in heat insulation and flame retardancy, which is the object of the present invention. Nothing about the foam is described.

Patent Document 10 describes a method for obtaining a novel flame-retardant styrene-based resin composition by combining a styrene-based resin with magnesium oxide having a specific particle size and a flame retardant. In Patent Document 10, it is possible to drastically improve the flame retardancy of a styrene-based resin by using magnesium oxide having a specific particle size, even if the conventional flame retardant is greatly reduced. Although it describes, it is not described at all about the styrene resin extrusion foam which was excellent in the heat insulation and flame retardance which were the objectives of this invention, and also excellent in heat resistance.
Japanese Patent Publication No.31-5393 Japanese Patent Publication No.42-19195 Japanese Patent Publication No.41-672 Japanese Patent Publication No.57-7175 JP-A-10-237210 JP 2003-206370 A JP 2003-342407 A JP 2003-342408 A Japanese Patent Publication No.42-25564 JP-A-5-39396

  As described above, in a system using saturated hydrocarbons as a foaming agent, it is a very difficult task to achieve flame retardancy while having high heat insulation performance and to obtain a foam excellent in heat resistance. .

  Under such circumstances, the problem to be solved by the present invention is to use a foaming agent having a tendency to burn easily, to have high heat insulation performance, and to sufficiently achieve a high degree of flame retardancy defined in JIS A9511. Another object of the present invention is to provide a styrenic resin extruded foam which is satisfied and further has improved heat resistance as compared with the conventional one and a method for producing the same.

  As a result of diligent research to solve the above problems, the present inventors use a halogen-based flame retardant and a small amount of a basic inorganic compound in a styrene resin extruded foam using hydrocarbon as a foaming agent. Thus, it has been found that while achieving excellent flame retardancy, the heat resistance is improved more than before. Furthermore, when water is used in combination as a foaming agent and a water-absorbing substance such as bentonite is added in combination, a foam having a specific cell structure in which large bubbles and small bubbles are mixed as described later is produced. In addition, the basic inorganic compound acts as a bubble adjusting agent, and thus the above-mentioned specific method can be performed without increasing the amount of inorganic porous material typified by talc or the like, which was generally necessary when adjusting the bubble diameter of the foam. It was found that the air bubbles can be adjusted without hindering the air bubble structure, and excellent heat insulating properties can be obtained.

That is, this invention provides the following styrene-type resin extrusion foam and its manufacturing method.
(1) A styrene resin extruded foam obtained by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming the foaming agent. As a foaming agent for 100 parts by weight of the styrene resin, a) 2 to 6 parts by weight of a saturated hydrocarbon having 3 to 5 carbon atoms, b) 1 to 7 parts by weight of a compound selected from the group consisting of methyl chloride, ethyl chloride and dimethyl ether, and / or c) a blowing agent a) b) And 0.1 to 10 parts by weight of a non-fluorocarbon foaming agent excluding the above, and d) 0.1 to 10 parts by weight of a halogenated flame retardant, and e) 0.01 to 10 parts of a basic inorganic compound. A styrene resin extruded foam containing 2 parts by weight, wherein the foam density is 20 to 50 kg / m ³ .
(2) The styrenic resin as described in (1) above, wherein the saturated hydrocarbon having 3 to 5 carbon atoms is at least one saturated hydrocarbon selected from the group consisting of propane, n-butane and i-butane. Extruded foam.
(3) The non-fluorocarbon foaming agent as component c) is at least one inorganic foaming agent selected from the group consisting of water, carbon dioxide and nitrogen, and / or 1 selected from methyl alcohol and ethyl alcohol. The styrene resin extruded foam according to the above item (1) or (2), which comprises various alcohols.
(4) The basic inorganic compound is at least one selected from the group consisting of oxides, hydroxides, carbonates, and silicates of alkali metals, alkaline earth metals, or Group 3 metals of the Periodic Table The styrene resin extruded foam according to any one of (1) to (3).
(5) Further, the phosphorous flame retardant is contained in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the styrenic resin, according to any one of the above items (1) to (4). Styrene resin extruded foam.
(6) Halogen flame retardant is hexabromocyclododecane, tetrabromocyclooctane, hexabromobenzene, tris (2,3-dibromopropyl) isocyanurate, tetrabromobisphenol A-bis (2,3-dibromopropyl ether) The styrene resin extruded foam according to any one of (1) to (5), which is at least one selected from the group consisting of:
(7) The styrene resin extruded foam according to any one of (5) to (6), wherein the phosphorus flame retardant is at least one selected from triphenyl phosphate and tris (tribromoneopentyl) phosphate. body.
(8) The items (1) to (7), wherein the basic inorganic compound is at least one selected from the group consisting of oxides of alkali metals, alkaline earth metals, or group 3 metals of the periodic table. The styrene resin extruded foam according to any one of the above.
(9) The styrene resin extruded foam according to any one of (1) to (8), wherein the basic inorganic compound is magnesium oxide.
(10) The bubbles forming the foam are mainly composed of bubbles having a bubble diameter of 0.25 mm or less and bubbles having a bubble diameter of 0.3 to 1 mm. These bubbles are dispersed in a sea-island shape through a bubble film, and foamed. The styrene-based resin extrusion foam according to any one of (1) to (9) above, wherein an area ratio of bubbles having a bubble diameter of 0.25 mm or less per body cross-sectional area is 10 to 90% body.
(11) Furthermore, 0.2 to 10 parts by weight of at least one compound selected from the group consisting of bentonite, hectorite and inorganic porous material is contained with respect to 100 parts by weight of styrene resin. The styrene resin extruded foam according to item (10).
(12) Any of the items (10) to (11), which does not contain a fluorocarbon foaming agent and has both heat insulation and flame retardancy, which conforms to three types of extruded polystyrene foam heat insulating plates specified in JIS A9511 The styrene resin extruded foam according to claim 1.
(13) The styrene resin extruded foam according to any one of (10) to (12), wherein the heat insulating property is 0.028 W / mK or less in terms of thermal conductivity.
(14) In the measurement of flammability prescribed in JIS A9511, the flame retardant is such that the flame disappears within 3 seconds, there is no residue, and the combustion limit indicator line is not burned. The styrene resin extruded foam according to any one of items (13) to (13).
(15) A method of producing a styrene resin extruded foam obtained by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming the foaming agent, and as a foaming agent with respect to 100 parts by weight of the styrene resin. A) 2-6 parts by weight of a saturated hydrocarbon having 3 to 5 carbon atoms, b) 1-7 parts by weight of a compound selected from the group consisting of methyl chloride, ethyl chloride and dimethyl ether, and / or c) a blowing agent a) 0.1 to 5 parts by weight of a non-fluorocarbon foaming agent excluding b), and d) 0.1 to 10 parts by weight of a halogenated flame retardant and e) a basic inorganic compound as a flame retardant. Any one of the items (1) to (14) above, which is an extruded foam of styrenic resin containing 0.01 to 2 parts by weight, wherein the foam density is 20 to 50 kg / m ^3. To produce extruded styrene resin foam .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture stably the styrene resin extrusion foam which was excellent in environmental compatibility, and was excellent in heat resistance with flame retardance and heat insulation. The styrene resin extruded foam of the present invention is particularly useful for use as a heat insulating material for buildings because of its excellent flame retardancy, heat insulation and heat resistance.

  The styrene resin used in the present invention is not particularly limited, and is obtained from a styrene homopolymer obtained only from a styrene monomer, a monomer copolymerizable with styrene monomer and styrene, or a derivative thereof. Examples thereof include random, block or graft copolymers, modified polystyrene such as brominated polystyrene and rubber-reinforced polystyrene. These can be used alone or in admixture of two or more.

  Examples of monomers copolymerizable with styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylonitrile, diene compounds such as budadiene or the like Derivatives, unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride and the like. These can be used alone or in admixture of two or more.

  Among styrenic resins, styrene homopolymer is preferable from the viewpoint of processability.

  The present invention provides, as a foaming agent, a) one or more kinds of saturated hydrocarbons having 3 to 5 carbon atoms, b) at least one compound selected from the group consisting of methyl chloride, ethyl chloride, and dimethyl ether, and / or C) Foaming agent A) A non-fluorocarbon foaming agent other than b) is used in combination at a specific ratio.

  Examples of the saturated hydrocarbon having 3 to 5 carbon atoms used as component a) in the present invention include propane, n-butane, isobutane, n-pentane, isopentane, neopentane and the like. Among saturated hydrocarbons having 3 to 5 carbon atoms, 2 are selected from the group consisting of propane, n-butane, and isobutane alone, or propane, n-butane, and isobutane from the viewpoint of foamability and thermal insulation performance of the foam. In the case where a seed or a mixture of three species is preferred and higher thermal insulation performance is desired, n-butane, isobutane alone or a mixture of n-butane and isobutane is more preferred, and when higher thermal insulation performance is desired. Isobutane is most preferred.

  In the present invention, at least one compound selected from the group consisting of methyl chloride, ethyl chloride, and dimethyl ether used as component b) can be used arbitrarily, but is preferably non-halogen from the environmental viewpoint. Therefore, it is preferable to use dimethyl ether alone.

  As the non-fluorocarbon foaming agent used as the component c) in the present invention, from the viewpoint of foamability, foam formability, and the like, inorganic foaming agents such as water, carbon dioxide and nitrogen, methyl alcohol, ethyl alcohol and the like Alcohols are preferred. These can be used alone or in admixture of two or more.

  By using the non-fluorocarbon foaming agent, a good plasticity effect and a foaming aid effect can be obtained, the extrusion pressure can be reduced, and the foam can be stably produced.

  In particular, when water is used as a foaming agent, in the foam, bubbles having a bubble diameter of approximately 0.25 mm or less (hereinafter referred to as small bubbles) and a bubble diameter of approximately 0.3 to 1 mm are used. A foam having a characteristic bubble structure in which relatively large bubbles (hereinafter referred to as large bubbles) are mixed in a sea-island shape is obtained, and the foam characteristics, moldability, productivity and heat insulation of the resulting foam are obtained. Performance is improved.

  The amount of the foaming agent added or injected into the styrenic resin during the production of the styrene resin extruded foam of the present invention is appropriately changed according to the setting value of the expansion ratio, etc. The total amount is preferably 2 to 20 parts by weight, more preferably 3 to 18 parts by weight with respect to 100 parts by weight of the styrene resin. If the addition amount of the foaming agent is less than the above range, the foaming ratio is low, and the characteristics such as light weight and heat insulation as the resin foam may be difficult to be exhibited. May cause defects such as voids.

  Regarding the addition amount of each foaming agent component, a) the amount of one or two or more saturated hydrocarbons having 3 to 5 carbon atoms is 2 to 6 parts by weight with respect to 100 parts by weight of the styrenic resin, and b ) The amount of at least one compound selected from the group consisting of methyl chloride, ethyl chloride and dimethyl ether is 1 to 7 parts by weight, and c) the amount of the non-fluorocarbon blowing agent is 0.1 to 5 parts by weight. . When the amount of the saturated hydrocarbon having 3 to 5 carbon atoms is less than the above range, the heat insulating property of the obtained foam may be inferior. On the other hand, when it exceeds the above range, desired flame retardancy cannot be obtained.

  Further, if the amount of at least one compound selected from the group consisting of methyl chloride, ethyl chloride, and dimethyl ether is less than the above range, it is necessary to increase the resin temperature in order to reduce the pressure in the extruder, resulting in closed cells. On the other hand, if the amount is larger than the above range, the plasticity is too high, the kneading state of the styrene resin and the foaming agent in the extruder becomes uneven, and the pressure control of the extruder tends to be difficult.

  Further, if the amount of the non-fluorocarbon foaming agent is less than the above range, the specific large and small cell structure in the present invention cannot be obtained, while if it exceeds the above range, the kneading state of the styrene resin and the foaming agent in the extruder is not good. It becomes uniform and the pressure control of the extruder tends to be difficult.

  In the present invention, other foaming agents may be used in addition to the foaming agent components a), b) and c). Such other blowing agents include alcohols such as propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, t-butyl alcohol, diethyl ether, methyl ethyl ether, diisopropyl ether, di n-butyl ether, diisopropyl ether, furan, Ethers such as furfural, 2-methylfuran, tetrahydrofuran, tetrahydropyran, dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone , Ketones such as ethyl n-propyl ketone, ethyl n-butyl ketone, formic acid methyl ester, formic acid ethyl ester, formic acid propyl ester Butyl formate ester formate, amyl esters, methyl propionate, organic foaming agent such as carboxylic acid esters such as propionic acid ethyl ester, and the like can be used chemical blowing agents such as, for example, azo compounds. These other foaming agents can be used alone or in admixture of two or more. These other foaming agents can be added to the extent that the production, appearance and physical properties of the foam are not impaired.

  The pressure when adding or injecting the foaming agent is not particularly limited as long as it is higher than the internal pressure of an extruder or the like.

  In the present invention, the styrene resin extruded foam obtained by extrusion foaming contains, as a foaming agent, a) at least one kind of saturated hydrocarbon having 3 to 5 carbon atoms. When the amount of the saturated hydrocarbon having 3 to 5 carbon atoms in the foaming agent remaining in the foam is less than the above range (2 to 6 parts by weight with respect to 100 parts by weight of the styrene resin), good heat insulation performance is obtained. There is a tendency to be difficult to be.

  The residual content of saturated hydrocarbons having 3 to 5 carbon atoms in the obtained styrene resin extruded foam varies depending on the type of saturated hydrocarbon compound, the density of the foam, etc., but generally 100 parts by weight of the foam The amount is preferably 2 to 6 parts by weight. More preferably, 2.5 to 6 parts by weight of propane, 2 to 6 parts by weight of n-butane and isobutane, and 2 to 6 parts by weight of n-pentane, isopentane and neopentane are used from the viewpoint of heat insulation performance and flame retardancy. preferable.

  In the present invention, the styrene resin extruded foam contains at least one selected from d) a halogen flame retardant as a flame retardant.

  Examples of the halogen-based flame retardant used in the present invention include, as brominated flame retardants, hexabromocyclododecane, tetrabromocyclooctane, dibromoneopentyl glycol, tribromoneopentyl alcohol, tris (2,3-dibromopropyl). ) Brominated aliphatic or alicyclic hydrocarbons such as isocyanurate, tetrabromoethane, hexabromobenzene, pentabromotoluene, ethylenebispentabromodiphenyl, decabromodiphenyl, decabromodiphenylethane, decabromodiphenyl ether, octabromo Brominated aromatic compounds such as diphenyl ether and 2,3-dibromopropylpentabromophenyl ether, tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromo Propyl ether), tetrabromobisphenol A (2-bromoethyl ether), tetrabromobisphenol A diglycidyl ether, tetrabromobisphenol A bis (allyl ether), an adduct of tetrabromobisphenol A diglycidyl ether and tribromophenol, tetra Brominated bisphenols such as bromobisphenol S and tetrabromobisphenol S-bis (2,3-dibromopropyl ether) and derivatives thereof, tetrabromobisphenol A polycarbonate oligomer, addition of tetrabromobisphenol A diglycidyl ether and brominated bisphenol Brominated bisphenol derivatives oligomers such as epoxy oligomers, ethylene bistetrabromophthalimide, bis (2,4,6 Tribromophenoxy) ethane, tris (tribromophenoxy) triazine, brominated aromatic compounds such as brominated acrylic resins, ethylene bis-dibromo norbornane dicarboximide and the like. Examples of the chlorinated flame retardant include chlorinated aliphatic compounds such as chlorinated paraffin, chlorinated naphthalene, and perchloropentadecane, chlorinated aromatic compounds, and chlorinated alicyclic compounds. These halogen flame retardants can be used alone or in admixture of two or more.

  Among the halogen-based flame retardants, brominated flame retardants are preferable from the viewpoint of flame retardancy, and hexabromocyclododecane, tetrabromocyclooctane, hexabromobenzene, tris (particularly from the viewpoint of compatibility with styrene-based resins, etc. 2,3-dibromopropyl) isocyanurate and tetrabromobisphenol A-bis (2,3-dibromopropyl ether) are preferred.

  Content of a halogen-type flame retardant is 0.1-10 weight part with respect to 100 weight part of styrene resin, Preferably it is 1-8 weight part.

  If the content of the halogen-based flame retardant is less than the above, the flame retardancy targeted by the present invention tends to be difficult to obtain. On the other hand, if the content exceeds the above range, moldability during foam production may be impaired. is there.

  Furthermore, in the present invention, at least one selected from phosphorus-based flame retardants is allowed to coexist with the halogen-based flame retardant, so that even when a highly flammable hydrocarbon is used as a blowing agent, a high degree of JIS A9511 is prescribed. It is preferable because flame retardancy can be stably achieved.

  Examples of the phosphorus flame retardant used in the present invention include phosphate ester compounds, and the phosphate ester compounds include halogen-containing phosphate ester compounds and halogen-free phosphate ester compounds.

  Specific examples of the halogen-containing phosphate ester compounds include tris (halogenated alkyl) such as tris (2-chloroethyl) phosphate, tris (chloropropyl) phosphate, tris (dichloropropyl) phosphate, tris (tribromoneopentyl) phosphate, and the like. ) Halogenated phosphate compounds such as phosphates.

  Specific examples of the halogen-free phosphate ester compounds include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate (the alkyl group preferably has 1 to 12 carbon atoms) , Trialkoxyalkyl phosphate such as tributoxyethyl phosphate (preferably alkoxyalkyl group having 2 to 12 carbon atoms), dimethyl phosphate, diethyl phosphate, dibutyl phosphate, diisodecyl phosphate, dialkyl such as di (2-ethylhexyl) phosphate Monoalkyl phosphates (as alkyl groups, preferably alkyl groups having 1 to 12 carbon atoms), monoisodecyl phosphate, etc. C1-C12 are preferred), aliphatic phosphate esters such as 2-acryloyloxyethyl acid phosphate, acyloxyalkyl phosphates such as 2-methacryloyloxyethyl acid phosphate, triphenyl phosphate, tricresyl phosphate , Trixyl phosphate, tris (isopropylphenyl) phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, di (isopropylphenyl) phenyl phosphate, etc. Group, which may be substituted with a phenyl group, diphenyl (2-ethylhexyl) phosphate, diphenyl (2-acrylic group). Aromatic phosphate esters such as diarylalkyl phosphates such as yloxyethyl) phosphate and diphenyl (2-methacryloyloxyethyl) phosphate, and diaryl acyloxyalkyl phosphates (aryl groups and alkyl groups may be substituted) Can be given. These phosphorus flame retardants can be used alone or in admixture of two or more. Among the phosphorus-based flame retardants, tris (tribromoneopentyl) phosphate and triphenyl phosphate are particularly preferable because of the large synergistic effect in combination with the halogen-based flame retardant.

  The phosphorous flame retardant content is higher than the flame retardancy of the halogen flame retardant alone, so that a higher flame retardancy and a synergistic effect of suppressing ignition and combustion of hydrocarbons that volatilize during combustion can be obtained. It is 0.1-3 weight part with respect to 100 weight part of styrenic resin, Preferably it is 0.3-3 weight part. When the content of the phosphorus-based flame retardant is less than the above range, a synergistic effect tends to be difficult to be obtained. On the other hand, when the content exceeds the above range, moldability during foam production may be impaired.

  In the present invention, at least one selected from halogen-based flame retardants and at least one selected from phosphorus-based flame retardants are used in an appropriate amount within the above-described range, so that the contribution mechanism to flame retardancy has not yet been determined. Although there is probably no styrene resin extruded foam, radicals generated during combustion are captured by halogen, and incombustible gas generated by decomposition, melting, etc. decreases the oxygen concentration around the combustion site, flame retardant coating or carbon foam coating It is presumed that a synergistic effect of inhibiting combustion such as formation of a flame retardant layer or a heat insulating layer is produced by the formation of, and high flame retardancy tends to be easily obtained.

  That is, when a saturated hydrocarbon is used as the foaming agent, the residual foaming agent is released from the foam into the atmosphere during combustion of the foam, and the foaming agent burns, so that the foaming heat is generated by the combustion heat of the foaming agent. There is a tendency for surface melting to spread and spread. However, with respect to these tendencies, combustion of the residual foaming agent can be inhibited by using a halogen-based flame retardant and adding at least one compound selected from phosphorus-based flame retardants. Can be reduced or eliminated, and by using an appropriate amount, a foam molded article having excellent flame retardancy and molding stability can be obtained. .

  Further, in the present invention, a basic inorganic compound is used as a heat resistance improver, a flame retardant synergist, and a bubble regulator.

  The basic inorganic compound used in the present invention is preferably an oxide, hydroxide, carbonate, or silicate of an alkali metal, an alkaline earth metal, or a group 3 metal of the periodic table. Metal oxides such as lithium oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, barium oxide, aluminum oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, water Hydroxides such as barium oxide and aluminum hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, carbonates such as aluminum carbonate, potassium silicate, sodium silicate, magnesium silicate, calcium silicate, silicic acid Examples include silicates such as barium and aluminum silicate. One or more can be used.

  Among these, oxides of alkali metals, alkaline earth metals, or Group 3 metals of the periodic table are preferable, and the effects as heat resistance improvers, flame retardant synergists, and bubble regulators are remarkable. Particularly preferred is magnesium oxide.

  Content of a basic inorganic compound is 0.01-2 weight part with respect to 100 weight part of styrene resin, Preferably it is 0.03-1 weight part. If the content of the basic inorganic compound is less than the above, the target heat resistance of the present invention tends to be difficult to obtain. On the other hand, if it exceeds the above range, moldability during foam production may be impaired. .

  When water is mainly used as the non-fluorocarbon foaming agent as the component c) of the present invention, at least one compound selected from bentonite, hectorite, and inorganic porous materials is used. These compounds act as an absorptive substance that absorbs the non-fluorocarbon foaming agent, and allow the non-fluorocarbon foaming agent to be uniformly dispersed in the styrene resin.

  Bentonite as used in the present invention is composed mainly of montmorillonite (a thin silicate layer having a thickness of about 1 nm, the surface of the plate-like crystal particles is negatively charged, and an exchangeable positive electrode such as sodium or calcium is interposed between the layers. This is a clay mineral that maintains neutrality in charge through ions and hydrates with the exchangeable cations between layers when water comes in contact with them, and swells between the layers. Quartz, α-Cristobalite, Opal It is a basic clay mineral containing accompanying minerals such as feldspar and mica.

  Examples of the bentonite used in the present invention include natural bentonite and purified bentonite. In addition, montmorillonite-modified products such as organic bentonite, anionic polymer-modified montmorillonite, silane-treated montmorillonite, and highly polar organic solvent composite montmorillonite are also included in the category.

  Examples of hectorite used in the present invention include natural hectorite and synthetic hectorite. In addition, modified products such as organic treatment, anionic polymer modification, and silane treatment are also included in the category.

  Examples of the inorganic porous material used in the present invention include silicon dioxide, silica gel, activated carbon, zeolite, and calcium silicate.

  As the absorbent material of the non-fluorocarbon foaming agent, absorbent or absorption-swelling clay such as saponite and swellable fluorine mica, an organically treated product thereof, a water-absorbing polymer compound, and the like can also be used. These absorptive substances can also be used in combination with the bentonite, hectorite, and inorganic porous substance.

  The blending amount of at least one compound selected from bentonite, hectorite, and inorganic porous material is preferably 0.2 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the styrenic resin. Part. When the compounding amount of the compound is less than the above range, not only the target large / small cell structure tends to be hardly obtained, but also the absorption and / or adsorption amount of the non-fluorocarbon foaming agent is insufficient, There is a tendency that pores are generated due to non-dispersion of the non-fluorocarbon foaming agent such as water in the machine, resulting in a defective molded body. On the other hand, when the amount is larger than the above range, gel non-dispersion occurs in the extruder, air bubbles become uneven, and the heat insulation performance of the foam deteriorates and tends to vary.

  When obtaining a foam having a large and small cell structure which is an object of the present invention, small cells having a cell diameter of 0.25 mm or less have an occupied area ratio of 5 to 90% per cross-sectional area of the foam. The occupied area ratio of the small bubbles is preferably 10 to 85%, more preferably 15 to 80%, and most preferably 15 to 70% per cross-sectional area of the foam. As described above, it is preferable that the small bubble occupation area ratio is large because the heat insulation performance is improved.

  In the present invention, conventionally known bubble diameter adjusting agents such as talc, wollastonite, kaolin, clay, etc. may be used. These bubble regulators are preferably used in an amount of 3 parts by weight or less based on 100 parts by weight of the styrene resin. When the amount exceeds 3 parts by weight, the formation of the large and small cell structure which is the object of the present invention tends to be inhibited, and when the amount exceeds 6 parts by weight, the moldability tends to be remarkably deteriorated such as poor appearance of the foam.

  In the present invention, an inorganic compound such as silica, mica, zinc oxide, titanium oxide, calcium carbonate, sodium stearate, magnesium stearate, barium stearate, fluidity as long as the effect of the present invention is not inhibited as necessary. Processing aids such as paraffin, olefinic wax, stearylamide compounds, phenolic antioxidants, phosphorus stabilizers, light-resistant stabilizers such as benzotriazoles, hindered amines, other flame retardants, antistatic agents, pigments Additives such as coloring agents can be included.

In the present invention, a styrene resin extruded foam obtained by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming the foaming agent, B) at least one kind of saturated hydrocarbon having 3 to 5 carbon atoms, and b) at least one compound selected from the group consisting of methyl chloride, ethyl chloride and dimethyl ether, 1 to 7 parts by weight, And / or c) 0.1 to 5 parts by weight of a non-fluorocarbon foaming agent excluding a) b), and as a flame retardant, d) at least one selected from halogenated flame retardants 0.1 Extruded polystyrene containing 10 parts by weight, further comprising e) 0.01 to 2 parts by weight of a basic inorganic compound, having a foam density of 20 to 50 kg / m ³ and prescribed in JIS A9511 Foam insulation board Matches the species, it is possible to obtain a styrene resin extruded foam having both a high degree of thermal insulation and flame retardancy. That is, the thermal insulation is 0.028 W / mK or less in terms of thermal conductivity, and the flame retardancy is flammability measured in JIS A9511, the flame disappears within 3 seconds, there is no residue, It is possible to obtain a styrene resin extruded foam that satisfies the condition that it does not burn beyond the combustion limit indicator line. Furthermore, it is possible to obtain a styrene resin extruded foam having better heat resistance than conventional ones.

  Styrenic resin extruded foam that has both heat insulation and flame retardancy, which conforms to the three types of extruded polystyrene foam insulation plates specified in JIS A9511, is a saturated hydrocarbon having 3 to 5 carbon atoms as a blowing agent. Preferably, n-butane and / or isobutane is used, particularly preferably isobutane is used, and at least one compound selected from the group consisting of methyl chloride, ethyl chloride, and dimethyl ether is used. It is preferable to use water as the fluorocarbon foaming agent. In particular, it is particularly preferable to use water as a foaming agent and to have a specific bubble structure in which small bubbles and large bubbles are mixed as described above. In the case of this specific cell structure, it is preferable to use the water-absorbing substance described above, and among these, it is particularly preferable to use bentonite, hectorite, or an inorganic porous substance. Any of the compounds shown in the present invention can be preferably used as the halogen-based flame retardant, but preferably hexabromocyclododecane, tetrabromocyclooctane, hexabromobenzene, tris (2,3-dibromopropyl) isocyanurate, Tetrabromobisphenol A-bis (2,3-dibromopropyl ether), particularly preferably hexabromocyclododecane. In addition, the phosphoric acid ester compound is used as a phosphoric acid ester compound so that a higher flame retardancy than the flame retardancy of a halogen-based flame retardant alone and a synergistic effect of ignition / combustion suppression of hydrocarbons that volatilize during combustion can be obtained. Any of the compounds shown in the invention can be preferably used, but triphenyl phosphate and tris (tribromoneopentyl) phosphate are preferable.

  Furthermore, a small amount of a basic inorganic compound acts as a flame retardant synergist, and it is possible to adjust the air bubbles without inhibiting the specific air bubble structure, and further, a styrenic resin having improved heat resistance than before. A resin extruded foam can be obtained.

  The styrene resin extruded foam of the present invention comprises (1) a styrene resin mixed with a halogen flame retardant, a basic inorganic compound, and other additives as required, and then heated and melted; (2) styrene After the resin is heated and melted, a halogen-based flame retardant, a basic inorganic compound, and other additives as necessary are added and mixed; (3) a halogen-based flame retardant, a basic inorganic compound, and if necessary, styrene resin After mixing other additives, prepare a heated and melted composition, then supply it to an extruder and heat and melt it again; various methods such as styrene resin, halogen flame retardant, basic inorganic compound, necessary Depending on the conditions, other additives are supplied to a heat-melting and kneading means such as an extruder, and the foaming agent is added to the styrenic resin under high-pressure conditions at any stage, forming a fluid gel, and at a temperature suitable for extrusion foaming. Cool and flow The gel was extruded foam the low pressure region through a die, it is produced by forming a foam.

  There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the styrene resin and additives such as a foaming agent. The heating temperature may be equal to or higher than the temperature at which the styrenic resin used melts, but is preferably a temperature at which molecular degradation of the resin due to the influence of a flame retardant is suppressed as much as possible, for example, about 150 to 220 ° C. The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means and the like, and thus cannot be determined unconditionally. However, the time required for uniformly dispersing and mixing the styrenic resin and the foaming agent is appropriately selected. The melt kneading means is, for example, a screw type extruder, but is not particularly limited as long as it is used for ordinary extrusion foaming. However, in order to suppress the molecular deterioration of the resin as much as possible, it is preferable to use a low shear type screw for the screw shape.

  Also, the foam molding method is not particularly limited. For example, the foam obtained by releasing the pressure from the slit die is used to form a large cross-sectional area using a molding die and a molding roll installed in close contact with or in contact with the slit die. A general method for forming a plate-like foam can be used.

The thickness of the foam of the present invention is not particularly limited and is appropriately selected depending on the application. For example, in the case of a heat insulating material used for a building material or the like, in order to give preferable heat insulating properties, bending strength and compressive strength, the thickness is not as thin as a sheet but as a normal plate. Is preferable, usually 1 to 150 mm, preferably 10 to 100 mm. The density of the foam of the present invention is preferably 20 to 50 kg / m ³ in order to give light weight and excellent heat insulation, bending strength and compressive strength.

  Next, although the styrene resin extrusion foam of this invention and its manufacturing method are demonstrated in detail based on an Example, this invention is not restrict | limited only to this Example. Unless otherwise specified, “parts” represents parts by weight, and “%” represents% by weight.

  As the characteristics of the foams obtained in Examples 1 to 10 and Comparative Examples 1 to 7 shown below, appearance, density, small bubble occupation area ratio, thermal conductivity, combustibility, glass transition temperature, heat resistance of the foam Were examined according to the following method. Finally, comprehensive evaluation was made with “Excellent” being “Excellent”, “Good” being excellent, and “X” having some problem with the characteristics.

1) Appearance The appearance of the foam was visually inspected, and “◎” indicates that the appearance is extremely good, “◯” indicates that the appearance is good, and “×” indicates that the appearance is extremely poor such as voids or cracks.

2) Density (kg / m ³ )
The foam density was determined based on the following formula, and the unit was shown in terms of kg / m ³ .

Foam density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ )

3) Small bubble occupation area ratio (%)
The occupied area ratio per cross-sectional area of the foam having a bubble diameter of 0.25 mm or less was determined as follows. Here, a bubble having a bubble diameter of 0.25 mm or less is a bubble having an equivalent circle diameter of 0.25 mm or less.
a) Magnify 30 times with a scanning electron microscope (manufactured by Hitachi, Ltd., product number: S-450) and photograph a longitudinal section of the foam.
b) An OHP sheet is placed on the photograph taken, and a portion corresponding to a bubble having a diameter in the thickness direction larger than 7.5 mm (corresponding to a bubble having an actual dimension larger than 0.25 mm) is black ink. Fill in and copy (primary processing).
c) The primary processed image is taken into the image processing apparatus (Pierce Co., Ltd., product number: PIAS-II), and the dark color portion and the light color portion, that is, the portion painted with black ink are identified.
d) Of the dark portion, a portion corresponding to the area of a circle having a diameter of 7.5 mm or less, that is, a portion having a long diameter in the thickness direction but only an area of a circle having a diameter of 7.5 mm or less. Is lightened to correct the dark portion.
e) Using “FRACTAREA (area ratio)” in the image analysis calculation function, the area ratio of the bubble diameter of 7.5 mm or less (light color portion divided by shading) in the entire image is obtained by the following equation.

  Small bubble occupation area ratio (%) = (1−area of dark color portion / area of entire image) × 100

4) Thermal conductivity (W / mK)
It measured according to JIS A9511. The measurement was performed on a foam that had passed 30 days after production.

5) Combustibility 14 days after production, according to JIS A9511, a test piece having a thickness of 10 mm, a length of 200 mm and a width of 25 mm was used, and a combustion test (measurement method A) was performed using five test pieces. The determination was made according to the following criteria.
Burning time ◎: All 5 flame extinguishing times are within 3 seconds. ○: Out of 5 flame extinguishing times, at least one exceeds 3 seconds, but the remaining 3 or more are within 3 seconds. Δ: Flame extinguishing time. Of the five, at least three of them exceed 3 seconds, but the remaining one or more are within 3 seconds. X: All 5 flame extinguishing times exceed 3 seconds. Stops, no combustion of the foaming agent is observed. ○: Combustion stops within the combustion limit indicator line, and some combustion of the foaming agent is observed. Δ: Combustion exceeds the combustion limit indicator line, and the foaming agent burns. Is observed, but does not lead to complete burning. X: Combustion of the foaming agent is also observed and complete burning.

6) Glass transition temperature The foam was stabilized for 24 hours at room temperature for 7 days after production, and the temperature was raised to 220 ° C. at a rate of temperature increase of 10 ° C./min with a differential differential calorimeter according to JIS K7121. Hold for one minute and then cool to 30 ° C. at 10 ° C./min. The step-like change when the temperature was raised again to 200 ° C. and cooled to 30 ° C. was measured according to the method for obtaining the transition temperature of JIS K7121.

7) Heat resistance of foam A foam which had passed 30 days after production was cut into a 25 mm thick, 100 mm square and heated in a hot air dryer at 80 ° C. for 24 hours to show the volume change rate before and after heating.
The volume change rate of 5% or less was “◯”, and 5% or more was “x”.

(Example 1)
For 100 parts of polystyrene resin (manufactured by Kaneka Chemical Industry Co., Ltd., trade name: KPS, melt index (MI): 3.1), 0.2 parts of talc and 0.5 parts of barium stearate as additives, Hexabromocyclododecane (HBCD) 4.0 parts as a halogen-based flame retardant, bentonite (manufactured by Toyoshun Mining Co., Ltd., trade name: Bengel 11) as a water-absorbing substance, silicon dioxide (Shionogi Pharmaceutical Co., Ltd.) ), Product name: Carplex) 0.1 parts, 0.2 parts of magnesium oxide as a basic inorganic compound was dry blended, and the resulting resin mixture was connected in series with a diameter of 65 mm and a diameter of 90 mm. It was supplied to the two-stage extruder at a rate of about 50 kg / hr. The resin mixture supplied to the extruder having a diameter of 65 mm is heated to 200 ° C. to melt or plasticize and knead, and the resin temperature is cooled to 120 ° C. with an extruder having a diameter of 90 mm connected thereto. Extruded into the atmosphere from a rectangular cross-section die having a thickness direction of 2 mm and a width direction of 50 mm provided at the tip of the extruder, a rectangular solid extruded foam having a thickness of about 50 mm and a width of about 150 mm was obtained. At this time, 4.0 parts of isobutane, 2.0 parts of dimethyl ether, and 0.8 parts of water were added as foaming agents to 100 parts of polystyrene resin, respectively, in the vicinity of the tip of the 65 mm diameter extruder (90 mm diameter). From the end of the extruder on the side opposite to the end of the extruder). The properties of the obtained foam are shown in Table 1. A foam having both high flame retardancy and heat insulation performance, and having improved heat resistance as compared with Comparative Example 1 below was obtained.

（実施例２）
塩基性無機化合物として酸化マグネシウムを０．５部に変更した以外は、実施例１と同様の条件で押出発泡体を得た。得られた発泡体の特性を表１に示す。高度な難燃性能と断熱性能の両立し、更に下記の比較例１と比較して耐熱性の向上した発泡体が得られた。

(Example 2)
Extruded foam was obtained under the same conditions as in Example 1 except that magnesium oxide was changed to 0.5 part as the basic inorganic compound. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardancy and heat insulation performance, and having improved heat resistance as compared with Comparative Example 1 below was obtained.

(Example 3)
Extruded foam was prepared under the same conditions as in Example 1 except that 1.0 part of tris (tribromoneopentyl) phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: CR900) was used as the phosphorus flame retardant. Obtained. The properties of the obtained foam are shown in Table 1. A foam having both high flame resistance and heat insulation performance and improved heat resistance as compared with Comparative Example 2 below was obtained.

Example 4
Extruded foam was obtained under the same conditions as in Example 1 except that 1.0 part of triphenyl phosphate (manufactured by Ajinomoto Fine Techno Co., Ltd., trade name: Leophos TPP) was used as the phosphorus flame retardant. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardance performance and heat insulation performance and further improved heat resistance as compared with Comparative Example 3 below was obtained.

(Example 5)
Extruded foams were obtained under the same conditions as in Example 3 except that 4.0 parts of methyl chloride was used in place of dimethyl ether as the foaming agent. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardancy and heat insulation performance, and having improved heat resistance as compared with Comparative Example 1 below was obtained.

(Example 6)
Extruded foams were obtained under the same conditions as in Example 5 except that the foaming agent was changed to 3.0 parts of isobutane and 1.0 part of propane. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardancy and heat insulation performance, and having improved heat resistance as compared with Comparative Example 1 below was obtained.

(Example 7)
An extruded foam was obtained under the same conditions as in Example 3 except that 5.0 parts of tris (2,3-dibromopropyl) isocyanurate was used as the halogen-based flame retardant instead of HBCD. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardance performance and heat insulation performance and having improved heat resistance as compared with Comparative Example 4 below was obtained.

(Example 8)
Extruded foams were obtained under the same conditions as in Example 3 except that 7.0 parts of tetrabromobisphenol A-bis (2,3-dibromopropyl ether) was used in place of HBCD as the halogen flame retardant. The properties of the obtained foam are shown in Table 1. A foam having both high flame retardance performance and heat insulation performance and further improved heat resistance as compared with Comparative Example 5 below was obtained.

Example 9
For 100 parts of polystyrene resin (manufactured by Kaneka Chemical Industry Co., Ltd., trade name: KPS, melt index (MI): 3.1), 0.2 parts of talc and 0.5 parts of barium stearate as additives, 4.0 parts of hexabromocyclododecane (HBCD) as a halogen-based flame retardant and 0.2 parts of magnesium oxide as a basic inorganic compound are dry blended, and the resulting resin mixture having a diameter of 65 mm and a diameter of 90 mm is connected in series. Was fed at a rate of about 50 kg / hr. The resin mixture supplied to the 65 mm diameter extruder is melted or plasticized and kneaded by heating to 200 ° C., and the resin temperature is cooled to 120 ° C. with a 90 mm diameter extruder connected thereto. Extruded into the atmosphere from a rectangular cross-section die having a thickness direction of 2 mm and a width direction of 50 mm provided at the tip of the extruder, a rectangular solid extruded foam having a thickness of about 50 mm and a width of about 150 mm was obtained. At this time, as a foaming agent, 4.0 parts of isobutane and 2.0 parts of dimethyl ether were added to 100 parts of polystyrene resin from different lines, respectively, near the tip of the 65 mm diameter extruder (the diameter of the 90 mm diameter extruder) The resin was press-fitted into the resin from the opposite end side). The properties of the obtained foam are shown in Table 1. A foam having both high flame retardance performance and heat insulation performance and improved heat resistance as compared with Comparative Example 6 below was obtained.

(Example 10)
An extruded foam was obtained under the same conditions as in Example 9 except that 5.0 parts of tris (2,3-dibromopropyl) isocyanurate was used as the halogen-based flame retardant instead of HBCD. The properties of the obtained foam are shown in Table 1. A foam having both high flame resistance and heat insulation performance and improved heat resistance as compared with Comparative Example 7 below was obtained.

(Comparative Example 1)
Extruded foams were obtained under the same conditions as in Example 1 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared to Example 1, the heat resistance is inferior.

(Comparative Example 2)
Extruded foams were obtained under the same conditions as in Example 3 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared with Example 3, heat resistance is inferior.

(Comparative Example 3)
Extruded foams were obtained under the same conditions as in Example 4 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared with Example 4, heat resistance is inferior.

(Comparative Example 4)
Extruded foam was obtained under the same conditions as in Example 7 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared with Example 7, heat resistance is inferior.

(Comparative Example 5)
Extruded foams were obtained under the same conditions as in Example 8 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared with Example 8, heat resistance is inferior.

(Comparative Example 6)
Extruded foams were obtained under the same conditions as in Example 9 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared with Example 9, heat resistance is inferior.

(Comparative Example 7)
Extruded foam was obtained under the same conditions as in Example 10 except that the basic inorganic compound was not added. The properties of the obtained foam are shown in Table 1. Compared to Example 10, the heat resistance is inferior.

Claims (15)

A styrene-based resin extruded foam obtained by heating and melting a styrene-based resin, adding a foaming agent, and extruding and foaming the same. As a foaming agent with respect to 100 parts by weight of the styrene-based resin, a) having a carbon number 2-6 parts by weight of a saturated hydrocarbon that is 3-5, b) 1-7 parts by weight of a compound selected from the group consisting of methyl chloride, ethyl chloride, dimethyl ether, and / or c) a blowing agent a) b) And 0.1 to 10 parts by weight of a halogen-based flame retardant, and e) 0.01 to 2 parts by weight of a basic inorganic compound. A styrene resin extruded foam containing a styrene resin, wherein the foam density is 20 to 50 kg / m ³ .   The styrene resin extruded foam according to claim 1, wherein the saturated hydrocarbon having 3 to 5 carbon atoms is at least one kind of saturated hydrocarbon selected from the group consisting of propane, n-butane and i-butane.   The non-fluorocarbon foaming agent as component c) is at least one inorganic foaming agent selected from the group consisting of water, carbon dioxide and nitrogen, and / or one alcohol selected from methyl alcohol and ethyl alcohol. 3. A styrene resin extruded foam according to claim 1 or 2, comprising   2. The basic inorganic compound is at least one selected from the group consisting of an alkali metal, an alkaline earth metal, or an oxide, hydroxide, carbonate, or silicate of a Group 3 metal in the periodic table. The styrene resin extrusion foam of any one of -3.   Furthermore, 0.1-3 weight part of phosphorus flame retardants are contained with respect to 100 weight part of styrene resin, The styrene resin extruded foam of any one of Claims 1-4 characterized by the above-mentioned. .   Halogen flame retardant is selected from hexabromocyclododecane, tetrabromocyclooctane, hexabromobenzene, tris (2,3-dibromopropyl) isocyanurate, tetrabromobisphenol A-bis (2,3-dibromopropyl ether) The styrene resin extruded foam according to any one of claims 1 to 5, which is at least one kind.   The styrene resin extruded foam according to any one of claims 5 to 6, wherein the phosphorus flame retardant is at least one selected from triphenyl phosphate and tris (tribromoneopentyl) phosphate.   The basic inorganic compound is at least one selected from the group consisting of an alkali metal, an alkaline earth metal, or an oxide of a group 3 metal of the periodic table. Styrene resin extruded foam.   The styrene resin extruded foam according to any one of claims 1 to 8, wherein the basic inorganic compound is magnesium oxide.   The bubbles forming the foam are mainly composed of bubbles having a bubble diameter of 0.25 mm or less and bubbles having a bubble diameter of 0.3 to 1 mm. These bubbles are dispersed in the form of sea islands through the bubble film, and the cross-sectional area of the foam The styrene-based resin extruded foam according to any one of claims 1 to 9, wherein an area ratio of bubbles having a bubble diameter of 0.25 mm or less is 10 to 90%.   Furthermore, 0.2-10 weight part of at least 1 sort (s) of compounds chosen from the group which consists of bentonite, a hectorite, and an inorganic porous material is contained with respect to 100 weight part of styrene resin. Styrene resin extruded foam.   The styrene-based resin extruded foam according to claim 10 or 11, which does not contain a freon-based foaming agent and has both heat insulating properties and flame retardancy, conforming to three types of extruded polystyrene foam heat insulating plates specified in JIS A9511. body.   The styrenic resin extruded foam according to any one of claims 10 to 12, wherein the heat insulating property is 0.028 W / mK or less in terms of thermal conductivity.   Any one of claims 10 to 13, wherein the flame retardancy satisfies the condition that the flame disappears within 3 seconds, there is no residue, and the combustion limit indicator line is not burned in the flammability measurement specified in JIS A9511. The styrene resin extruded foam according to claim 1. A method for producing an extruded foam of a styrene resin obtained by heating and melting a styrene resin, adding a foaming agent, and extruding and foaming the foaming agent. 2 to 6 parts by weight of a saturated hydrocarbon having 3 to 5 carbon atoms, b) 1 to 7 parts by weight of a compound selected from the group consisting of methyl chloride, ethyl chloride and dimethyl ether, and / or c) a blowing agent a) b And 0.1 to 5 parts by weight of a non-fluorocarbon foaming agent excluding)), and as a flame retardant, d) 0.1 to 10 parts by weight of a halogenated flame retardant, and e) 0.01% of a basic inorganic compound The styrene resin extrusion foam according to any one of claims 1 to 14, wherein the styrene resin extrusion foam contains ~ 2 parts by weight, and the foam density is 20 to 50 kg / m ^3. A method for producing a foam.