JP2014129449A - Method for manufacturing polystyrene resin extruded foam board and polystyrene resin extruded foam board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polystyrene resin extruded foam board that can stably produce a polystyrene resin extruded foam board having high heat insulation properties over a long period of time and having excellent flame retardancy and to provide a polystyrene resin extruded foam board having high heat insulation properties and excellent flame retardancy.SOLUTION: The method for manufacturing a polystyrene resin extruded foam board comprises extrusion foaming a melt of a foamable resin produced by kneading a polystyrene resin as a base material resin with a physical foaming agent, a flame retardant, scaly graphite and aluminum powder. The addition amount (X) of the scaly graphite is 0.2-1 pt.wt. based on 100 pts.wt. of the base material resin. The addition amount (Y) of the aluminum powder is 0.05-0.8 pt.wt. based on 100 pts. wt. of the base material resin. The ratio (X/Y) of the addition amount (X) of the scaly graphite to the addition amount (Y) of the aluminum powder is 0.5-15.

Description

  The present invention relates to a method for producing a polystyrene resin extruded foam plate, and a polystyrene resin extruded foam plate obtained by the production method.

  As a heat insulating material for buildings, a polystyrene-based resin extruded foam plate (hereinafter also simply referred to as an extruded foam plate) having excellent heat insulation and high flame retardancy and suitable mechanical strength is widely used. Has been. Such an extruded foam plate is generally obtained by extruding and foaming a foamable melt-kneaded product obtained by melting and kneading a polystyrene resin and a physical foaming agent in an extruder from a die attached to the end of the extruder to a low pressure region. It is manufactured by forming it into a plate shape through a shaping device.

  In the production of extruded foam plates, chlorofluorocarbons, chlorofluorocarbons containing hydrogen atoms, and fluorocarbons such as fluorinated hydrocarbons have been used as physical foaming agents. From the viewpoints of protection and prevention of global warming, aliphatic hydrocarbons such as normal butane, isobutane, normal pentane and isopentane, and alicyclic hydrocarbons such as cyclopentane and isopentane (hereinafter these are also simply referred to as “hydrocarbons”). Is used).

  Since hydrocarbons themselves have high combustibility, if a large amount is blended in an attempt to lower the thermal conductivity of the extruded foam plate, it becomes extremely difficult to impart sufficient flame retardancy to the resulting extruded foam plate. Moreover, since hydrocarbons gradually escape from the extruded foam plate, the thermal conductivity of the extruded foam plate also gradually increases.

In order to solve these problems, attempts have been made to blend graphite, aluminum powder and titanium oxide into the base resin constituting the extruded foam plate.
For example, in Patent Document 1, a fine powder having an infrared reflectance of 40% or more is uniformly dispersed in a resin to produce an extruded foam plate, and the thermal conductivity is reflected by the infrared powder being reflected and attenuated by the fine powder. It is proposed that aluminum powder and graphite be used.

  Patent Document 2 proposes an extruded foam plate in which graphite is added to a base resin using a mixed foaming agent containing 25 to 70 mol% of isobutane and / or isopentane.

Japanese Unexamined Patent Publication No. 63-183941 JP 2004-196907 A

  However, in the method of adding the fine powder reflecting infrared rays described in the example of Patent Document 1, graphite and aluminum powder are used individually, and the addition amount is also a large amount of 5 parts by weight. ing. When these fine powders are added in a large amount, the flame retardancy is lowered, and even if a halogen-based flame retardant widely used in polystyrene foam is added in the same amount as before, sufficient flame retardancy cannot be imparted. Adding a large amount of flame retardant is expected to improve the flame retardancy, but excessive addition of the flame retardant will reduce the foaming properties, thus reducing the closed cell ratio and mechanical properties of the resulting polystyrene foam. There is a problem that it is difficult to invite or reduce the density.

  Moreover, when using graphite as a thermal conductivity reducing material like patent document 1, 2, if the addition amount of a graphite is increased, the heat insulation of an extrusion foaming board can be improved. However, if the amount of graphite added is too large, the bubbles will become too fine, even if the moldability in the process of forming into a plate shape after extrusion foaming is reduced, or extrusion foamed plates can be molded There is a problem that the oxygen index is lowered. Further, when graphite is added in a large amount, the blackness of the obtained foam becomes high, and there is a problem that heat storage, deformation, and deterioration of the extruded foam plate may occur if left for a long time outdoors.

  In view of the above problems, the present invention provides a production method capable of stably obtaining a polystyrene resin extruded foam plate having a high degree of heat insulation over a long period of time and excellent in flame retardancy, and has a high degree of heat insulation. It is an object of the present invention to provide a polystyrene resin foam board having excellent flame retardancy.

According to this invention, the manufacturing method of the polystyrene-type resin extrusion foam board shown below and the polystyrene-type resin extrusion foam board are provided.
[1] A method for producing a polystyrene resin extruded foam plate, in which a foamable resin melt obtained by kneading a base resin containing a polystyrene resin, a physical foaming agent, a flame retardant, scaly graphite and aluminum powder is extruded and foamed. There,
The addition amount (X) of the flaky graphite is 0.2 to 1 part by weight with respect to 100 parts by weight of the base resin,
The addition amount (Y) of the aluminum powder is 0.05 to 0.8 parts by weight with respect to 100 parts by weight of the base resin, and the addition of the scaly graphite to the addition amount (Y) of the aluminum powder The ratio (X / Y) of the amount (X) is 0.5 to 15, wherein the method for producing a polystyrene-based resin extruded foam plate is provided.
[2] The total of the addition amount (X) of the flaky graphite and the addition amount (Y) of the aluminum powder is less than 1.5 parts by weight with respect to 100 parts by weight of the base resin. The manufacturing method of the polystyrene-type resin extrusion foam board as described in [1].
[3] The method for producing a polystyrene-based resin extruded foam plate according to [1] or [2], wherein the aluminum powder has an average particle diameter of 5 to 50 μm.
[4] The polystyrene system according to any one of [1] to [3], wherein the scaly graphite has an average particle size of 25 μm or less and an apparent density of 0.25 g / cm ³ or less. Manufacturing method of resin extrusion foam board.
[5] The apparent density of the polystyrene resin extruded foam plate is 0.02 to 0.05 g / cm ³ , the thickness is 10 to 150 mm, and the average cell diameter in the thickness direction is 0.06 to 0.8 mm. The manufacturing method of the polystyrene-type resin extrusion foam board in any one of [1]-[4] characterized by the above-mentioned.
[6] A polystyrene resin extruded foam plate having an apparent density of 0.02 to 0.05 g / cm ³ , a thickness of 10 to 150 mm, and an average cell diameter in the thickness direction of 0.06 to 0.8 mm,
The polystyrene-based resin extruded foam plate contains scaly graphite and aluminum powder and a flame retardant, and the content of the scaly graphite is 0.2 to 1 part by weight with respect to 100 parts by weight of the base resin. The content of the aluminum powder is 0.05 to 0.8 parts by weight with respect to 100 parts by weight of the base resin, and the amount of the scaly graphite added (X) relative to the amount of the aluminum powder added (Y) ) Ratio (X / Y) of 0.5 to 15 is a polystyrene-based resin extruded foam board.

  According to the production method of the present invention, an extruded foam plate having better heat insulation than conventional ones is obtained by blending a specific amount of flaky graphite and a specific amount of aluminum powder into a base resin and performing extrusion foaming. It is possible to stably obtain a polystyrene-based resin extruded foam plate that is excellent in flame retardancy without degrading bubbles, without impairing moldability in the process of forming an extruded foam into a plate shape. Can do.

  In addition, the polystyrene-based extruded foam plate of the present invention includes a specific amount of scaly graphite and a specific amount of aluminum powder, so that it has low thermal conductivity and has excellent flame retardancy. It can be suitably used as a heat insulating material for buildings such as floors, walls, and roofs.

Hereinafter, the manufacturing method of the polystyrene-type resin extrusion foam board of this invention and the polystyrene-type resin extrusion foam board are demonstrated in detail.
In the method for producing a polystyrene resin extruded foam plate according to the present invention, a foamable resin melt obtained by kneading a base resin containing a polystyrene resin, a physical foaming agent, a flame retardant, scaly graphite and aluminum powder is extruded and foamed. By doing so, a polystyrene-based resin extruded foam (hereinafter also simply referred to as an extruded foam or a foam) is produced. Specifically, a polystyrene resin is obtained by extruding a foamable resin melt obtained by kneading the raw materials such as polystyrene resin in an extruder into a low pressure region through a die in a low pressure region. An extruded foam board is manufactured. At this time, an apparatus (hereinafter also referred to as a guider) composed of two upper and lower plates made of polytetrafluoroethylene resin or the like installed at the outlet of the die so as to expand in parallel or gently from the inlet to the outlet. ) Or a molding roll and the like, and the extruded foam can be shaped into a plate shape by passing through the molding tool.

  Examples of the polystyrene resin include polystyrene, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-maleic anhydride copolymer, styrene-methyl methacrylate copolymer, and styrene-polyphenylene ether. Copolymer, Styrene-acrylonitrile copolymer, Acrylonitrile-butadiene-styrene copolymer, Acrylonitrile-styrene-acrylate copolymer, Styrene-butadiene copolymer, Styrene-methylstyrene copolymer, Styrene-dimethylstyrene copolymer Styrene-based copolymers mainly composed of styrene, such as styrene-ethylstyrene copolymer, styrene-diethylstyrene copolymer, impact-resistant polystyrene (HIPS), a mixture of polystyrene and polyphenylene ether, etc. It is shown. These polystyrene resins can be used alone or in combination of two or more. The styrene component content in the styrene copolymer is preferably 50% by weight or more, and more preferably 70% by weight or more.

  The base resin in the present invention contains a polystyrene resin. From the viewpoint that it is easy to obtain an extruded foam plate having excellent foamability and excellent balance between heat insulation and mechanical properties, the base resin is preferably composed mainly of polystyrene. The material resin preferably contains 50% by weight or more of styrene homopolymer, more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably 80% by weight or more.

  In the base resin in the present invention, other resins other than the polystyrene-based resin can be mixed within a range that does not impair the objects and effects of the present invention. Examples of other resins include polyethylene resins, polypropylene resins, acrylic resins such as polymethyl methacrylate, and polyester resins. Moreover, styrene-type elastomers, such as a styrene-butadiene-styrene block copolymer elastomer and its hydrogenated product, a styrene-isoprene-styrene block copolymer elastomer and its hydrogenated product, can also be mix | blended. The blending amount of the other resin and the styrene elastomer is preferably 30% by weight or less (including 0) in the base resin, more preferably 20% by weight or less (including 0), and still more preferably. Is 10% or less (including 0), particularly preferably 5% or less (including 0).

In the method of the present invention, a mixture of polystyrene and a styrene-methyl methacrylate copolymer and / or polymethyl methacrylate, or a mixture of polystyrene and an amorphous polyester resin can be used as a base resin. If these mixtures are used, the radiant heat between bubble membranes can be suppressed and the heat conductivity of an extrusion foaming board can be reduced.
Examples of the amorphous polyester resin include cyclohexanedimethanol-modified polyethylene terephthalate, neopentyl glycol-modified polyethylene terephthalate, and spiro glycol-modified polyethylene terephthalate.

  In the method of the present invention, in order to stably obtain an extruded foam plate having a low thermal conductivity, maintaining the low thermal conductivity for a long period of time, and having a high degree of flame retardancy, a specific amount of flaky graphite and a specific amount are used. A quantity of aluminum powder is used in combination.

The reason why graphite can lower the thermal conductivity of the extruded foam is considered as follows.
In the extruded foam board, heat is transferred by heat conduction of the resin itself, heat conduction by the gas (residual foaming agent and atmospheric components) in the foam of the extruded foam board, and its convection, and the bubbles are formed in multiple layers. Heat is also transmitted by infrared radiation between the bubble membranes. Since graphite has a function as an infrared absorbing material, when graphite is mixed in the resin constituting the extruded foam plate, the graphite reduces the infrared radiation between the bubble films (infrared absorption effect), and the extruded foam plate It is considered that the thermal conductivity can be lowered.

  Furthermore, by combining aluminum powder with graphite, the thermal conductivity of the extruded foam plate is effectively lowered. That is, since aluminum powder is a material that is generally known to have high infrared reflectance, this aluminum powder diffuses infrared radiation (infrared reflection effect) and improves the infrared absorption efficiency of the graphite. Therefore, it is considered that the thermal conductivity of the extruded foam plate can be effectively lowered even if the amount of graphite added is small.

  The graphite used in the method of the present invention is scaly graphite. The average particle diameter of the scaly graphite that can be obtained is about 1 to 300 μm, but in the method of the present invention, the average particle diameter is preferably 3 to 50 μm. When graphite having an average particle diameter in this range is used, it is difficult to form cell nuclei during foaming, so that a stable extruded foam plate can be produced without deteriorating foam moldability, and an excellent infrared absorption effect is obtained. From this viewpoint, the average particle size is more preferably 5 to 25 μm.

Apparent density of the scaly graphite average cell diameter is about 3~50μm is 0.05~0.30g / cm ³ approximately, 0.1~0.25g / cm ³ is more preferable.

  In this specification, the average particle diameter of graphite means a volume average particle diameter (d50). For example, the average particle diameter (d50) can be measured as the particle diameter when the resin fine particles are dispersed in water, the particle size distribution is measured by a laser diffraction method, and the cumulative volume with respect to the volume of all particles is 50%. (JIS Z8901: 2006).

  The apparent density of the graphite used in the present specification is determined according to JIS K7365: 1999.

  In addition, graphite used in the manufacture of extruded foam plates has good workability when added to polystyrene-based resins to produce high-concentration master batches, and is excellent in the heat insulating effect of extruded foam plates Therefore, graphite having a fixed carbon content of 90% or more is preferable. In order to further enhance the heat insulating properties of the extruded foam plate, the graphite preferably has a fixed carbon content of 93% or more, more preferably 95% or more. The fixed carbon content of the graphite is a value measured by the method described in JIS M8511: 2005.

  In the method of the present invention, the addition amount (X) of the scaly graphite is 0.2 to 1 part by weight with respect to 100 parts by weight of the base resin. If the amount added is too small, the desired heat insulation property may not be exhibited. On the other hand, if the amount added is too large, the blackness of the resulting extruded foam plate becomes high, and if it is left outdoors for a long time, heat accumulation, deformation, and deterioration of the extruded foam plate may occur. Moreover, there is a possibility that the moldability at the time of forming into a plate shape and the oxygen index (LOI) of the extruded foam plate are deteriorated. From this viewpoint, the addition amount is preferably 0.2 to 0.9 parts by weight, more preferably 0.2 to 0.6 parts by weight.

  In the method of the present invention, aluminum powder is added to the base resin together with the scaly graphite.

As the aluminum powder, those produced by a stamp mill, a dry ball mill, a wet ball mill, an atomization or the like can be used. In grinding, a grinding aid such as stearic acid may be used. Alternatively, a paste-like aluminum powder containing a solvent such as mineral spirits may be used.
As the aluminum powder, a spherical shape, a granular shape, a plate shape, a scale shape, a flake shape, an indefinite shape, a needle shape, or the like can be used. From the viewpoint of efficiently reflecting infrared rays, flakes and scales are preferred.

  The average particle diameter of the aluminum powder is preferably 5 to 50 μm. Within this range, a foamed plate having good moldability can be obtained by efficiently irregularly reflecting infrared rays even when added in a small amount. If the average particle size is too large, foaming may be hindered and the cell walls of the foam plate may be destroyed. On the other hand, if it is too small, since the aluminum powder is fine, it tends to agglomerate and may not be finely dispersed in the extruded foam plate. From the above viewpoint, it is more preferably 30 μm or less, and further preferably 20 μm or less.

  The measurement method of the average particle diameter of aluminum powder can be measured by the same measurement method as the measurement of the average particle diameter of the graphite.

The addition amount (Y) of the aluminum powder is 0.05 to 0.8 parts by weight with respect to 100 parts by weight of the base resin. If the amount added is too small, the desired effect of improving heat insulation is not exhibited. On the other hand, when there is too much this addition amount, there exists a possibility that foam moldability may worsen. Moreover, since aluminum powder itself has a high thermal conductivity, if the amount added is too large, the thermal conductivity of the extruded foam plate may be increased or the flame retardancy may be decreased.
From the above viewpoint, the addition amount (Y) of the aluminum powder is preferably 0.08 to 0.6 parts by weight, and more preferably 0.1 to 0.5 parts by weight.

  When the amount of graphite added is small, the probability of existence of graphite in the foam is low, so there is a high probability that infrared rays due to radiation between the foam bubble films will not be absorbed and transmitted, and sufficient thermal conductivity. It is considered that the reduction effect cannot be obtained. In the present invention, in addition to graphite in the foam, aluminum powder is added in a specific amount and in a specific ratio, so that infrared rays are diffusely reflected in the aluminum powder dispersed in the foam plate, and the infrared rays are efficiently absorbed by the graphite. I am letting. Thereby, even if the addition amount (X) of graphite is small, it is considered that infrared rays can be efficiently absorbed and the thermal conductivity of the extruded foam plate can be reduced. That is, by using the scaly graphite and the aluminum powder in combination, the aluminum powder diffuses the infrared rays, and the graphite can efficiently absorb the irregularly reflected infrared rays. It is considered that a synergistic effect of efficiently absorbing sucrose is expressed. From this viewpoint, the ratio (X / Y) of the addition amount (X) of the graphite to the addition amount (Y) of the aluminum powder is 1 to 15, preferably 1 to 6.

Moreover, the compounding quantity of each of a graphite and aluminum powder can be decreased according to the said synergistic effect. As a result, it is possible to stably produce a foamed plate that has a low thermal conductivity that cannot be achieved by the prior art and is excellent in heat insulation and also excellent in flame retardancy.
Moreover, it is preferable also from a viewpoint that extrusion foaming property and a flame retardance improve that this total addition amount decreases. Specifically, the total addition amount is preferably less than 1.5 parts by weight, more preferably 1.2 parts by weight or less, and still more preferably 0.9 parts by weight or less.

As a method of blending the scale-like graphite and aluminum powder into the base resin, a predetermined amount of graphite or aluminum powder is dry-blended with the base resin, and this blend is supplied to the extruder from the raw material supply section of the extruder. And kneading and blending in the molten base resin. Further, a master batch in which flaky graphite or aluminum powder is blended with a styrene resin in advance is prepared, and this is supplied to an extruder and melted and kneaded with a base resin to obtain a resin melt. In particular, it is preferable to adopt a master batch method from the viewpoint of dispersibility.
In addition, when supplying as a master batch, a master batch containing a predetermined amount of graphite and aluminum powder may be supplied, or a master batch of graphite and a master batch of aluminum powder may be supplied separately. .

In the method of the present invention, a flame retardant is further added to the base resin. As the flame retardant, a brominated flame retardant is preferably used. Examples of brominated flame retardants include tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), Tetrabromobisphenol A-bis (2-bromoethyl ether), tetrabromobisphenol A-bis (allyl ether), tetrabromobisphenol S, tetrabromobisphenol S-bis (2,3-dibromopropyl ether), hexabromocyclododecane , Tetrabromocyclooctane, tris (2,3-dibromopropyl) isocyanurate, tribromophenol, decabromodiphenyl oxide, tris (tribromoneopentyl) phosphate, N-2,3-dibromopropyl Pill-4,5-dibromo-hexahydrophthalimide, and brominated polymer flame retardant, for example, brominated polystyrene, brominated bisphenol ether derivative, brominated SBS block polymers, and the like brominated epoxy resin. These compounds can be used alone or in admixture of two or more. Among the above brominated flame retardants, the thermal stability is high and a high flame retardant effect can be obtained. Therefore, hexabromocyclododecane, tetrabromocyclooctane, tetrabromobisphenol A-bis (2,3-dibromo-2) -Methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tris (2,3-dibromopropyl) isocyanurate are particularly preferred.
In addition, in the method of this invention, a conventionally well-known flame retardant can also be used in an extrusion foaming board other than the said flame retardant.

  The amount of the flame retardant is preferably 1 to 6 parts by weight per 100 parts by weight of the base resin, in order to improve flame retardancy and minimize foaming and mechanical properties. 1 to 5 parts by weight is more preferable, and 2 to 4 parts by weight is still more preferable.

  Furthermore, in the method of the present invention, for the purpose of further improving the flame retardancy of the extruded foam plate, a small amount of a flame retardant aid can be used in combination with the above flame retardant. Examples of the flame retardant aid include 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, 3,4 -Diphenylalkanes such as diethyl-3,4-diphenylhexane, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, diphenylalkenes, poly-1,4 -Polyphenylalkanes such as diisopropylbenzene, triphenyl phosphate, cresyl di-2,6-xylenyl phosphate, antimony trioxide, antimony pentoxide, ammonium sulfate, zinc stannate, cyanuric acid, isocyanuric acid, triallyl isocyanurate, melamine Nitrogen-containing cyclic compounds such as cyanurate, melamine, melam, melem, Over emissions based compounds, boron oxide, zinc borate, inorganic compounds such as zinc sulfide, red phosphorus-based, ammonium polyphosphate, phosphorus-based compounds such as phosphazene and the like. These compounds can be used alone or in admixture of two or more.

  In addition, when supplying a flame retardant and a flame retardant auxiliary to an extruder, a method of supplying a dry blend of a flame retardant and a flame retardant auxiliary and a styrene resin to the extruder, a flame retardant and a flame retardant auxiliary, A method of supplying a melt-kneaded material kneaded with a styrene resin with a kneader etc. to an extruder, a method of supplying a liquid flame retardant previously heated and melted into an extruder, and a masterbatch containing a flame retardant and a flame retardant aid The method of producing and supplying to an extruder can be employ | adopted. In particular, from the viewpoint of dispersibility, it is preferable to employ a method in which a masterbatch containing a flame retardant and a flame retardant aid is prepared and supplied to the extruder.

In the method of the present invention, a bubble regulator can be added to adjust the bubble diameter of the extruded foam plate. Examples of the bubble regulator include talc, kaolin, mica, silica, calcium carbonate, clay, bentonite, diatomaceous earth and the like, and two or more bubble regulators can be used in combination. Among the various bubble regulators, talc is preferably used because it is easy to adjust the bubble diameter and does not hinder flame retardancy, and it is easy to reduce the bubble diameter. Talc having a median particle diameter of 0.1 to 10 μm, more preferably 0.5 to 5 μm is preferable.
When talc is used as the bubble regulator, the amount added is preferably 0.05 to 3 parts by weight with respect to 100 parts by weight of the base resin.

In the method of the present invention, the base resin and various additives are supplied to an extruder, melted and kneaded to obtain a melt, a physical foaming agent is pressed into the melt, and further kneaded to obtain a foamable resin. Let it be a melt.
The physical foaming agent is preferably a foaming agent having a conventionally known ozone depletion coefficient of zero (0). Furthermore, considering the maintenance of high heat insulation over a long period of time, those having relatively slow gas permeability to the base resin as shown below are preferable. Examples of the blowing agent having a relatively slow gas permeability include aliphatic hydrocarbons having 3 to 5 carbon atoms, specifically, propane, normal butane, isobutane, normal pentane, isopentane, neopentane, and the like. 6 alicyclic hydrocarbons, specifically, cyclobutane, cyclopentane, cyclohexane and the like. Among these, normal butane, isobutane, normal pentane, isopentane, and cyclopentane are more preferable because gas permeability is slow and foamability is excellent, and normal butane is excellent in handling properties in addition to gas permeability and foamability. Isobutane is preferred, and isobutane is particularly preferred. These foaming agents can be used alone or in combination of two or more.

  Further, within the range not impairing the intended purpose of the present invention, trans-1,3,3,3-tetrafluoropropene (trans HFO-1234ze), cis-1,3,3,3-tetrafluoropropene ( Hydrofluoroolefins (HFO) such as cis HFO-1234ze) and 1,1,1,2-tetrafluoropropene (HFO-1234yf) can also be used as a blowing agent.

  Furthermore, in consideration of the flame retardancy of the obtained extruded foam plate, the amount of hydrocarbons as described above is limited, so when producing an extruded foam plate with a small apparent density, It is preferable to use a mixed foaming agent used in combination with a foaming agent having a gas permeability with respect to the base resin of the extruded foam plate that is faster than that of the hydrocarbon. By using a mixed foaming agent, the amount of hydrocarbon added can be reduced and foamability can be enhanced. When a mixed foaming agent is used, most of the foaming agent with high gas permeability is dissipated from the extruded foam plate immediately after foaming, so that an extruded foam plate with a low apparent density can be obtained. The compounding quantity of the hydrocarbon in it can be adjusted to a desired quantity.

  Examples of the foaming agent having a high gas permeability include alkyl chloride, alcohols, ethers, ketones, carbon dioxide, water and the like. Among these blowing agents, alkyl chlorides having 1 to 3 carbon atoms, aliphatic alcohols having 1 to 4 carbon atoms, ethers having 1 to 3 carbon atoms in the alkyl chain, carbon dioxide, water, and the like are preferable. Specifically, examples of the alkyl chloride having 1 to 3 carbon atoms include methyl chloride and ethyl chloride. Examples of the aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, propyl alcohol, isopropyl alcohol, butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, aryl alcohol, crotyl alcohol, propargyl alcohol and the like. . Examples of ethers having 1 to 3 carbon atoms in the alkyl chain include dimethyl ether, ethyl methyl ether, diethyl ether, and methylene dimethyl ether. In particular, methyl chloride, dimethyl ether, carbon dioxide, and water are particularly preferable among the foaming agents because of their high gas permeability and excellent handleability. These foaming agents can be used alone or in combination of two or more.

The amount of the foaming agent used is appropriately selected in relation to the desired apparent density. In order to obtain an extruded foam plate having an apparent density of 0.02 to 0.05 g / cm ³ , it is usually mixed per 1 kg of polystyrene resin. 0.5-3 mol is added as a foaming agent, Preferably 0.6-2.5 mol is added.

  When the polystyrene resin extruded foam plate obtained by the method of the present invention is used as a heat insulating plate for construction, the standard of thermal conductivity defined in 4.2 of JIS A9511: 2006R, and the JIS A9511: 2006R 5.13.1 is required to simultaneously satisfy the flammability standard for the extruded polystyrene foam heat insulating plate described in “Measuring method A” defined in 5.13.1. Therefore, in order to reduce the thermal conductivity and improve the heat insulation, it is preferable that the amount of hydrocarbon added in the mixed foaming agent is large, and in order to improve flame retardancy, the amount of hydrocarbon added Is less preferable. Specifically, the lower limit of the blending amount is preferably 0.4 mol or more per 1 kg of the extruded foam board, more preferably 0.45 mol or more, and further preferably 0.5 mol or more. preferable. On the other hand, the upper limit of the amount of the hydrocarbon is preferably 0.9 mol or less, more preferably 0.8 mol or less, and even more preferably 0.7 mol or less per kg of the extruded foam board.

  In the present specification, the remaining amount of the foaming agent such as hydrocarbon in the extruded foam plate is a value measured by an internal standard method using a gas chromatograph. Specifically, an appropriate amount of sample is cut out from the extruded foam plate, placed in a sample bottle with a lid containing an amount of toluene and an internal standard that can completely dissolve the sample, and then sufficiently stirred. Gas chromatographic analysis is performed using a solution obtained by dissolving the foaming agent in the extruded foam plate in toluene as a measurement sample, and the residual amount of foaming agent in the extruded foam plate is determined.

Next, the polystyrene resin extruded foam plate of the present invention will be described.
The extruded foam plate of the present invention contains 0.2 to 1 part by weight of the scaly graphite with respect to 100 parts by weight of the base resin, and 0% of aluminum powder with respect to 100 parts by weight of the base resin. 0.05 to 0.8 part by weight. As described above, when the scaly graphite and the aluminum powder are used in combination, the aluminum powder irregularly reflects infrared rays, and the graphite can efficiently absorb the irregularly reflected infrared rays. As a result, it becomes possible to efficiently absorb infrared rays specifically compared to the case where each is used alone, and even with a small amount of each, it has a low thermal conductivity that could not be achieved with the prior art. The extruded foam plate is excellent in heat insulation and flame retardancy.

In extruded foam board of the present invention, preferably the apparent density of the 0.02~0.05g / cm ^3, more preferably 0.022~0.045g / cm ^3. When the apparent density is too small, the strength is too low to be used as a heat insulating material. On the other hand, when the apparent density is too large, the lightness is lost and the workability is deteriorated.
In addition, the apparent density of an extrusion foaming board can be calculated | required based on JISK7222: 1999.

  Moreover, 10-150 mm is preferable and, as for the thickness of this extrusion foaming board, More preferably, it is 20-100 mm. An extruded foam plate having a thickness in this range can be suitably used as a heat insulating plate. When the thickness is too thin, the strength is lowered or the heat insulating properties are lowered, and the heat insulating material cannot be used. On the other hand, when the thickness is too thick, the workability deteriorates.

The cross-sectional area of the extruded foam plate is preferably 60 cm ² or more, more preferably 100 cm ² or more. When the cross-sectional area is too narrow, the strength is lowered, the workability and the heat insulation are lowered, and the heat insulating material cannot be used. If it is in the said range, it can use suitably as a heat insulating board.

  Moreover, it is preferable that the average bubble diameter of the thickness direction of this extrusion foaming board is 0.06-0.8 mm, More preferably, it is 0.1-0.3 mm. When the average cell diameter in the thickness direction is within this range, the mechanical strength is excellent and the heat insulating property is higher. If the average cell diameter in the thickness direction is too small, an appropriate apparent density (foaming ratio) cannot be obtained, the strength of the foam itself is lowered, and a good foam may not be stably obtained. On the other hand, if the average cell diameter in the thickness direction is too large, the heat insulating property is lowered and the appearance may be deteriorated.

The measurement method of the average bubble diameter is as follows.
The average cell diameter in the thickness direction of the extruded foam plate (DT: mm) and the average cell size in the width direction of the extruded foam plate (DW: mm) are the vertical cross section in the width direction of the extruded foam plate (the vertical cross section perpendicular to the extrusion direction of the extruded foam plate). ), The average cell diameter in the longitudinal direction of the extruded foam plate (DL: mm) is the vertical cross section in the longitudinal direction of the extruded foam plate (vertical cross section that is parallel to the extrusion direction of the extruded foam plate and bisected at the center in the width direction) Is magnified and projected onto a screen or monitor using a microscope, etc., a line segment is drawn in the direction to be measured on the projected image, the number of bubbles intersecting the line segment is counted, and the length of the line segment (however, This length is not the length of the line segment on the enlarged projected image, but the length of the true line segment considering the magnification of the projected image.) Divided by the number of counted bubbles The average bubble diameter in each direction is obtained.

The measurement method of each average bubble diameter will be described in detail. The measurement of the average bubble diameter (DT: mm) in the thickness direction is a line extending over the entire thickness in the thickness direction at a total of three locations in the center and both ends of the vertical cross section in the width direction. Subtract the length of each line segment and the number of bubbles intersecting the line segment to obtain the average diameter of bubbles present on each line segment (length of line segment / number of bubbles intersecting the line segment), Let the arithmetic mean value of the average diameter of three places calculated | required be an average bubble diameter (DT: mm) of a thickness direction.
The average cell diameter in the width direction (DW: mm) is a width of a 3 mm long line segment at a position that bisects a total of three extruded foam plates in the center and both ends in the width direction. Pulled in the direction, a line segment with a length of 3 mm and (the number of bubbles intersecting with the line segment) -1 to the average diameter of bubbles existing on each line segment (3 mm / (number of bubbles intersecting with the line segment) − 1)) is obtained, and the arithmetic average value of the average diameters of the three obtained locations is defined as the average bubble diameter (DW: mm) in the width direction.
The average cell diameter in the longitudinal direction (DL: mm) is the thickness of the extruded foamed plate in the thickness direction at a total of three locations in the center and both ends of the longitudinal cross section obtained by cutting the test piece along the longitudinal direction. A line segment of 3 mm length is drawn in the longitudinal direction at a position equally divided into two, and the average of bubbles existing on each line segment from the line segment of 3 mm length (number of bubbles intersecting the line segment) -1 The diameter (3 mm / (number of bubbles intersecting with the line segment) -1)) is obtained, and the arithmetic average value of the obtained average diameters at the three locations is defined as the average bubble diameter (DL: mm) in the longitudinal direction. Moreover, let the average bubble diameter (DH: mm) of the horizontal direction of an extrusion foaming board be an arithmetic mean value of DW and DL.

  Furthermore, in the extruded foam plate of the present invention, the bubble deformation rate is preferably 0.7 to 2.0. The bubble deformation rate means a value (DT / DH) calculated by dividing DT obtained by the above measurement method by DH. The bubble deformation rate is flatter as the bubble deformation rate is smaller than 1. The larger it is, the longer it is. When the bubble deformation rate is within the above range, an extruded foam plate having excellent mechanical strength such as compressive strength and dimensional stability and high heat insulation can be obtained. From such a viewpoint, the bubble deformation rate is preferably 0.8 to 1.5, and more preferably 0.8 to 1.2.

The closed cell ratio of the extruded foam plate of the present invention is preferably 85% or more, and more preferably 93% or more. The higher the closed cell ratio, the higher the heat insulation performance can be maintained. The closed cell ratio is calculated by the following formula (1) using the true volume Vx of the extruded foamed plate measured using an air comparison type hydrometer 930 type manufactured by Toshiba Beckman Co., Ltd. according to the procedure C of ASTM-D2856-70. ) To calculate the closed cell ratio S (%).
As the sample, cut samples were cut out from three different portions on the extruded foamed plate, and each cut sample was measured. A cut sample is a sample which does not have a shaping | molding skin cut | disconnected to the magnitude | size of 25 mm x 25 mm x 20 mm from the extrusion foaming board. When the thickness is small and a 20 mm sample cannot be cut out in the thickness direction, for example, two samples (cut samples) cut into a size of 25 mm × 25 mm × 10 mm are stacked and measured.

S (%) = (Vx−W / ρ) × 100 / (VA−W / ρ) (1)
However, Vx: the true volume (cm ³ ) of the cut sample used for the above measurement (the volume of the resin composition constituting the cut sample of the extruded foam plate (including flaky graphite, aluminum powder, etc.) and the cut. (This corresponds to the sum of the total cell volume of the closed cell part in the sample.)
VA: apparent volume (cm ³ ) of the cut sample calculated from the outer dimensions of the cut sample used for measurement
W: Total weight of cut sample used for measurement (g)
ρ: Density (g / cm ³ ) of the resin composition (including the addition amount (X) of scaly graphite, the addition amount (Y) of aluminum powder, etc.) constituting the extruded foam plate

  As described above, the extruded foam plate of the present invention has excellent heat insulation properties by containing specific amounts of scaly graphite and aluminum powder. The thermal conductivity is preferably 0.0280 W / (m · K) or less, more preferably 0.0278 W / (m · K) or less, still more preferably 0.0275 W / (m · K) or less, particularly It is preferably 0.0273 W / (m · K) or less.

Thermal conductivity is measured in accordance with the heat flow meter method described in JIS A1412-2: 1999 (one specimen, symmetrical configuration method) under the temperature conditions of 38 ° C on the high temperature side, 8 ° C on the low temperature side, and 23 ° C on the flat air temperature. Is the value to be
Note that the thermal conductivity after a long period of time can be evaluated by measuring the thermal conductivity of a sample subjected to an accelerated test in accordance with ISO 11561. Specifically, for example, immediately after producing an extruded foam plate having a thickness of 50 mm, an accelerated test sample having a thickness of 10 mm is prepared by scraping evenly from both sides of the extruded foam plate, and 15 days after production. By measuring the thermal conductivity of the accelerated test sample, the thermal conductivity after about one year has passed after 375 days have passed since the 50 mm thick extruded foam plate was produced.

  Since the extruded foam board of the present invention contains the flame retardant, it is excellent in flame retardancy. Specifically, it can satisfy the flammability standard for the extruded polystyrene foam heat insulating plate described in “Measurement Method A” defined in 5.13.1 of JIS A9511: 2006R, and preferably JIS K7201. −1: The oxygen index LOI based on 1999 is preferably 26.0 or more.

  Hereinafter, the manufacturing method of the polystyrene-type resin extrusion foam board of this invention is demonstrated in detail by an Example. However, the present invention is not limited to the examples.

[material]
The types, manufacturers, product names, and physical properties of styrenic resins used in Examples and Comparative Examples are shown in Table 1 below. The types of graphite, manufacturers, product names, physical properties are shown in Table 2 below, and the types of aluminum powder, manufacturers, and products. Names and physical properties are shown in Table 3 below.

  A flame retardant, a bubble regulator, graphite, aluminum powder (scale-like), and titanium oxide were added as the following master batch.

  Flame retardant masterbatch: 50% by weight of tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether) (Daiichi Kogyo Seiyaku SR130) and tetrabromobisphenol-A-bis (2,3- (Dibromopropyl ether) (Daiichi Kogyo Seiyaku SR720) 50% by weight of a flame retardant masterbatch containing a mixed flame retardant becomes 3 parts by weight as a mixed flame retardant with respect to 100 parts by weight of the base resin. As such, it was added to the base resin.

Bubble control agent master batch: A talc master batch containing 60% by weight of talc (manufactured by Matsumura Sangyo Co., Ltd., trade name: High Filler # 12) was used with a polystyrene resin as a base resin.
Graphite masterbatch: A graphite masterbatch containing 40% by weight of graphite as shown in the table using a polystyrene resin as a base resin was used.
Aluminum powder masterbatch: An aluminum powder masterbatch containing 20% by weight of the aluminum powder shown in the table using a polystyrene resin as a base resin was used.
Titanium oxide master batch: A titanium oxide master batch containing polystyrene resin as a base resin and containing 70% by weight of titanium oxide was used.

[apparatus]
A first extruder having an inner diameter of 65 mm and a second extruder having an inner diameter of 90 mm are connected in series, a foaming agent inlet is provided near the end of the first extruder, and a resin outlet having a rectangular cross section ( A production apparatus in which a flat die equipped with a die lip) was connected to the outlet of the second extruder was used.
Further, a shaping device (guider) composed of a plate made of a pair of upper and lower polytetrafluoroethylene resins installed parallel to the resin outlet of the flat die is attached.

Examples 1-9, Comparative Examples 1-7
A polystyrene resin, a flame retardant masterbatch and a bubble regulator masterbatch are supplied to the first extruder so as to have the blending amounts shown in Tables 4 and 5, and heated to 220 ° C. to melt and knead them. Then, a physical foaming agent having a composition shown in Tables 4 and 5 is supplied to the melt at a ratio shown in Tables 4 and 5 from a foaming agent inlet provided near the tip of the first extruder and melted. It knead | mixed and it was set as the foamable resin melt. The foamable resin melt was introduced into the subsequent second extruder, and the resin temperature was expressed as a foaming suitable temperature as shown in Tables 4 and 5 (in the table, it was expressed as a foamed resin temperature. And the temperature of the foamable resin melt measured at the position of the joint part) and then extruded from the die lip into the guider at a discharge rate of 50 kg / hr, and in parallel with a gap of 28 mm in the thickness direction while foaming. By passing through the placed guider, it was molded (shaped) into a plate shape to produce a plate-like polystyrene-based resin extruded foam heat insulating plate.

In Tables 4 and 5, the additive amount [parts by weight] of the additives (graphite, aluminum powder), the flame retardant and the air bubble modifier is a value relative to 100 parts by weight of the base resin, and the additive amount [moles of the foaming agent] / Kg] is the amount added per kg of base resin.
In addition, each content of the graphite in the extrusion foamed board in this invention and aluminum powder is equal to the addition amount to base resin at the time of manufacturing an extrusion foamed board.

  Table 4 summarizes the physical properties of the extruded foam plates obtained in Examples, and Table 5 summarizes the physical properties of the extruded foam plates obtained in Comparative Examples.

From Examples 1 to 9, when a styrene resin extruded foam is produced based on the method of the present invention, a polystyrene resin extruded foam having excellent foam moldability, high flame retardancy and low thermal conductivity is obtained. You can see that

The comparative example 1 is an example which contains only scaly graphite in an extrusion foaming board, and since the obtained foaming board did not contain aluminum powder, the effect of reducing heat conductivity was small.
Comparative Examples 2 and 3 are examples in which only the aluminum powder is contained in the foamed plate, and the obtained foamed plate does not contain scaly graphite, so that the effect of reducing the thermal conductivity was small.
Comparative Example 4 is an example in which the amount of scaly graphite is too large. Although the obtained extruded foam board had low thermal conductivity, it had a low oxygen index and poor flame retardancy.
Comparative Example 5 is an example in which the amount of aluminum powder added is too large relative to the amount of flake graphite added (x / y = 0.5). Although the obtained extruded foam board had low thermal conductivity, it had a low oxygen index and poor flame retardancy.
Comparative Example 6 is an example using titanium oxide as an infrared reflecting agent. The obtained extruded foamed plate was added with titanium oxide, but titanium oxide had a lower thermal reflection effect than aluminum powder, and thus had high thermal conductivity and poor heat insulation.
Comparative Example 7 is an example in which no flaky graphite and aluminum powder are added. The obtained extruded foam board had high thermal conductivity and was inferior in heat insulation.

  In Examples and Comparative Examples, each physical property was measured and evaluated as follows.

(Measuring method of melt viscosity)
The melt viscosity in Table 1 is a value obtained by measuring with a capillograph model 1D manufactured by Toyo Seiki Seisakusho. For details of the measurement, a capillary with a hole diameter of 1.0 mm and a length of 10 mm is attached to the tip of a cylinder with an inner diameter of 9.55 mm (effective length of 250 mm), and the cylinder and capillary are heated to 200 ° C. and measured in the cylinder. A sample (resin pellet) was filled. After filling, the cylinder was filled with a piston and melted by preheating for 4 minutes. During the preheating, the piston was temporarily pushed down to sufficiently remove bubbles from the molten measurement sample. Further, the filling amount of the measurement sample was set to a sufficient amount that could secure 15 cc or more of the measurement sample after removing the bubbles. After completion of the preheating, the measurement sample in the cylinder was extruded with a piston so that the shear rate of the capillary part was 100 s ^−1, and the melt viscosity at that time was measured. The melt viscosity was measured after the conditions of 200 ° C. and 100 s ⁻¹ were adopted and the extrusion load was stabilized.

(Evaluation of foam moldability)
Evaluation of foam moldability in Tables 4 and 5 was evaluated according to the following evaluation criteria.
(Double-circle): A foaming state is especially favorable and a foam is obtained stably.
○: The foamed state is good, and the foam can be obtained stably.

(Flame retardant evaluation: Oxygen index LOI)
The oxygen index of the extruded foam plate was performed in accordance with JIS K7201-2: 2007. A flame retardance tester (ON-1D type) manufactured by Suga Test Instruments Co., Ltd. was used for measuring the oxygen index. In addition, the test piece was cut into a size of (thickness) 10 mm × (width) 10 mm × (length) 150 mm from the extruded foam plate after production of the extruded foam plate in an oven set at a temperature of 60 ° C. After sufficiently curing, it was subjected to measurement. The type of the heat source of the igniter was liquefied petroleum gas (LPG), the ignition procedure was method A, and the test piece was performed independently at a predetermined position in the tester. The test place temperature was 23 ° C. and humidity 50%.

(Flame retardant evaluation: JIS A9511)
In the flame retardancy evaluation in Tables 4 and 5, the extruded polystyrene foam described in the measurement method A of JIS A9511: 2006R 5.13.1 is obtained by cutting a test piece cut out from a plate-like extruded foam after 15 days from manufacture. Evaluation was performed in accordance with the flammability standard for the heat insulating plate.
For the measurement, five test pieces were cut out from one extruded foam plate and evaluated according to the following evaluation criteria.
○: Flame disappears in all test pieces within 3 seconds.
X: The average burning time of 5 test pieces exceeds 3 seconds.

(Measurement of thermal conductivity)
The thermal conductivity in Tables 4 and 5 was measured by the following method based on the accelerated test described in ISO 11561. A test piece having no molded skin of 200 mm × 200 mm × 10 mm was cut out from the central portion of the extruded foam plate immediately after production, and the test piece was stored in an atmosphere of 23 ° C. and humidity 50%. 15 days after production (corresponding to about 4 months after production of 28 mm thick extruded foam plate), using the test piece, compliant with the heat flow meter method (one specimen, symmetrical construction method) described in JIS A1412-2: 1999 The thermal conductivity was measured under the temperature conditions of a high temperature side of 38 ° C., a low temperature side of 8 ° C., and an average temperature of 23 ° C. The thermal conductivity of the extruded foam plate increases with time due to the replacement of the gas in the bubbles. Although it depends on the thickness of the extruded foam plate and the type of foaming agent, the thermal conductivity of the extruded foam plate is stable at the end of 4 months after production. Therefore, the measured value after 15 days in the accelerated test was adopted.

(Remaining foaming agent)
The remaining amount of foaming agent in the extruded foam plate was measured by the above method using a gas chromatograph. Specifically, a test piece without a molded skin of 200 mm × 200 mm × 10 mm cut out from an extruded foam plate immediately after production of the extruded foam plate was stored in an atmosphere of 23 ° C. and 50% humidity. 15 days after production (corresponding to about 4 months after the production of the 28 mm thick extruded foam plate), the sample was cut out from the test specimen so that the weight of the sample was 1 g. This sample was placed in a sample bottle with a lid containing toluene containing cyclopentane as an internal standard substance, and the lid was closed. Then, the sample was thoroughly stirred and a solution in which the blowing agent in the extruded foam plate was dissolved in toluene was used for measurement. As a sample, gas chromatographic analysis was performed to determine the remaining amount.

Measurement conditions for gas chromatographic analysis Column: Shinwa Kogyo Co., Ltd. Carrier: chromosorb W, 60-80 mesh, AW-DMCS treated product Liquid phase: Silicone DC550 (liquid phase amount 20%)
Column dimensions: Column length 4.1m, column inner diameter 3.2mm
Column material: Glass column temperature: 40 ° C
Inlet temperature: 200 ° C
Carrier gas: nitrogen carrier gas speed: 50 ml / min.
Detector: FID
Detector temperature: 200 ° C
Quantification: Internal standard method

(Whiteness)
Based on ASTM E313, the whiteness of the surface of the extruded foam was measured with a compact color meter X-Rite 948L manufactured by Color Techno System Co., Ltd.

Claims (6)

A method for producing a polystyrene-based resin extruded foam plate, which extrudes and foams a foamable resin melt obtained by kneading a base resin containing a polystyrene-based resin, a physical foaming agent, a flame retardant, scaly graphite and aluminum powder,
The addition amount (X) of the flaky graphite is 0.2 to 1 part by weight with respect to 100 parts by weight of the base resin,
The addition amount (Y) of the aluminum powder is 0.05 to 0.8 parts by weight with respect to 100 parts by weight of the base resin, and the addition amount of the scaly graphite with respect to the addition amount (Y) of the aluminum powder. (X) ratio (X / Y) is 0.5-15, The manufacturing method of the polystyrene-type resin extrusion foamed board characterized by the above-mentioned.
The total of the addition amount (X) of the flaky graphite and the addition amount (Y) of the aluminum powder is less than 1.5 parts by weight with respect to 100 parts by weight of the base resin. The manufacturing method of the polystyrene-type resin extrusion foam board as described in 2.
The average particle diameter of the said aluminum powder is 5-50 micrometers, The manufacturing method of the polystyrene-type resin extrusion foamed board of Claim 1 or 2 characterized by the above-mentioned.
4. The polystyrene-based resin extruded foam plate according to claim 1, wherein an average particle diameter of the flaky graphite is 25 μm or less and an apparent density is 0.25 g / cm ³ or less. Production method.
The polystyrene resin extruded foam plate has an apparent density of 0.02 to 0.05 g / cm ³ , a thickness of 10 to 150 mm, and an average cell diameter in the thickness direction of 0.06 to 0.8 mm. The manufacturing method of the polystyrene-type resin extrusion foam board in any one of Claims 1-4 characterized by the above-mentioned.
A polystyrene resin extruded foam plate having an apparent density of 0.02 to 0.05 g / cm ³ , a thickness of 10 to 150 mm, and an average cell diameter in the thickness direction of 0.06 to 0.8 mm,
The polystyrene resin extruded foam plate contains scaly graphite, aluminum powder and a flame retardant,
The content of the flaky graphite is 0.2 to 1 part by weight with respect to 100 parts by weight of the base resin,
The content of the aluminum powder is 0.05 to 0.8 parts by weight with respect to 100 parts by weight of the base resin, and the amount of the scaly graphite added (X) relative to the amount of the aluminum powder added (Y) ) Ratio (X / Y) of 0.5 to 15 is a polystyrene-based resin extruded foam board.