JP2014095048A - Method for manufacturing polystyrene resin extruded foamed plate and polystyrene resin extruded foamed plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which can stably obtain a polystyrene resin extruded foamed plate having high heat insulating properties for a long period of time and being excellent in flame retardancy.SOLUTION: In a method for manufacturing a polystyrene resin extruded foamed plate, a foamable resin molten material, which is obtained by kneading a physical foaming agent, a flame retardant, graphite, and an aluminum powder with a polystyrene resin as a base resin, is extruded and foamed. The average particle diameter of the graphite is 5-50 μm and the apparent density thereof is 0.3-0.8 g/cm. The added amount (X) of the graphite is 0.5-8 pts.wt. with respect to 100 pts.wt. of the base resin. The average particle diameter of the aluminum powder is 5-50 μm. The added amount (Y) of the aluminum powder is 0.15-1.5 pts.wt. with respect to 100 pts.wt. of the base resin.

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, for example, Patent Document 1 proposes an extruded foam plate in which a mixed foaming agent containing 25 to 70 mol% of isobutane and / or isopentane is used and graphite is added to a base resin. Yes.

  In Patent Documents 2 and 3, extrusion foaming is excellent in flame retardancy while maintaining low thermal conductivity by using graphite and inorganic particles such as titanium oxide together in a specific amount so as to satisfy a specific relationship. It has been proposed to obtain a board.

JP 2004-196907 A JP 2010-254780 A JP 2009-256426 A

However, with the recent increase in awareness of global environmental protection, from the viewpoint of energy saving, it has become necessary for heat insulating materials to maintain higher heat insulation and higher heat insulation than before.
As a method for improving the heat insulating property of the extruded foam plate, a method of increasing the amount of addition of graphite, titanium oxide or the like can be considered. However, in this method, if the amount of graphite added is too large, the bubbles become too fine and the moldability in the process of forming into a plate shape after extrusion foaming is reduced, or extrusion foamed plates can be molded Even if it is, there exists a problem that an oxygen index will fall. 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.
Moreover, increasing the addition amount of titanium oxide is also considered as a method for improving the heat insulating property of the extruded foam plate. However, if the amount of titanium oxide added is too large, the flame retardancy will decrease, so a large amount of flame retardant must be added, and as a result, extrusion stability is impaired.

  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-based resin extruded foam board, in which a foamable resin melt obtained by kneading a base resin containing a polystyrene-based resin, a physical foaming agent, a flame retardant, graphite and aluminum powder is extruded and foamed. ,
The average particle diameter of the graphite is 5 to 50 μm, the apparent density is 0.3 to 0.8 g / cm ³ , and the addition amount (X) of the graphite is 0.5 with respect to 100 parts by weight of the base resin. ~ 8 parts by weight,
The average particle diameter of this aluminum powder is 5-50 micrometers, and the addition amount (Y) of this aluminum powder is 0.15-1.5 weight part with respect to 100 weight part of said base resin, The polystyrene characterized by the above-mentioned. Of manufacturing a resin-based extruded foam board.
[2] The polystyrene-based resin extruded foam according to [1], wherein the ratio (X / Y) of the addition amount (X) of the graphite to the addition amount (Y) of the aluminum powder is 1 or more. A manufacturing method of a board.
[3] 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 of 0.08 to 0.8 mm. The manufacturing method of the polystyrene-type resin extrusion foam board of the said [1] or [2] characterized by the above-mentioned.
[4] 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 0.08 to 0.8 mm,
The polystyrene-based resin extruded foam plate contains graphite and aluminum powder and a flame retardant, and has an average particle diameter of 5 to 50 μm and an apparent density of 0.3 to 0.8 g / cm ³ . The graphite content is 0.5-8 parts by weight with respect to 100 parts by weight of the polystyrene-based resin,
The average particle diameter of the aluminum powder is 5 to 50 μm, and the content of the aluminum powder is 0.15 to 1.5 parts by weight with respect to 100 parts by weight of the polystyrene resin. Foam board.

  According to the method for producing a polystyrene-based resin extruded foam plate of the present invention, by using a graphite having a specific average particle diameter and an apparent density in combination with an aluminum powder having a specific average particle diameter, fine bubbles can be obtained. Polystyrene-based extruded resin foam with improved moldability in the process of forming extruded foam into a plate shape, and better heat insulation than conventional ones, and also excellent in flame retardancy Can be obtained stably.

  In addition, the polystyrene-based extruded foam plate of the present invention contains graphite having a specific average particle size and apparent density and aluminum powder having a specific average particle size, so that it has low thermal conductivity and excellent flame resistance. Therefore, it can be suitably used as a heat insulating material for buildings such as floors, walls, and roofs.

FIG. 1 is an electron micrograph of the graphite used in Example 1 (2500 times). FIG. 2 is an electron micrograph of the graphite used in Comparative Example 2 (4000 times).

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 of the present invention, a foamable resin melt obtained by kneading a base resin containing a polystyrene resin, a physical foaming agent, a flame retardant, graphite and aluminum powder is extruded and foamed. Thus, a polystyrene-based resin extruded foam (hereinafter also simply referred to as an extruded foam or a foam) is produced. Specifically, the foamable resin melt obtained by melting and kneading the raw materials such as polystyrene resin in an extruder is extruded into a low pressure region from the inside of the high pressure extruder through a die and foamed. The method of manufacturing a resin extrusion foam is mentioned. 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.

  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.

  The base resin in the present invention can be mixed with other resins other than the polystyrene-based resin within a range that does not impair the object 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 cyclohexane dimethanol modified PET, neopentyl glycol modified PET, spiro glycol modified PET, and the like.

  In the present invention, a specific graphite and a specific aluminum powder are used in combination 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 high flame retardancy. Used.

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, thereby lowering the thermal conductivity of the extruded foam plate. It is considered possible.

  Furthermore, by using aluminum powder together with graphite, the thermal conductivity of the extruded foam plate is effectively lowered. That is, since the aluminum powder is a material that is generally known to have a high infrared reflectance, the aluminum powder diffuses the infrared radiation and can improve the infrared absorption efficiency of the graphite. It is considered that the thermal conductivity of the extruded foam plate is effectively reduced.

The average particle size of graphite used in the method of the present invention is 5 to 50 μm. When graphite having an average particle diameter in this range is used, a stable extruded foam plate can be produced without reducing foam moldability.
The upper limit of the average particle diameter is not particularly limited as long as it does not inhibit foaming, but is preferably 40 μm, and more preferably 30 μm. The lower limit of the average particle diameter is approximately 5 μm.

The apparent density of the graphite used in the method of the present invention is 0.3 to 0.8 g / cm ³ . When the apparent density of graphite is too small, foaming is likely to be inhibited as described above, so the lower limit is preferably 0.35 g / cm ³ . The upper limit is preferably 0.65 g / cm ³ .
In the case of scale-like graphite, which is a general and typical graphite, the apparent density varies depending on the average particle diameter, but in the case where the average particle diameter is in the range of 5 to 50 μm, the apparent density is approximately 0.1. ˜0.2 g / cm ³ .

  Since the graphite used in the present invention has a high apparent density and is not bulky, the existence probability in the thickness direction of the extruded foam plate is lower than that of general graphite such as scales. As a result, at the same addition amount, the effect of reducing infrared radiation is considered to be inferior to general graphite. Moreover, compared with general graphite, it is considered that the existence probability is low as the reason why the black extruded foam plate is thin.

  Examples of a method for obtaining graphite that simultaneously satisfies the average particle diameter and the apparent density include, for example, a method of repeatedly adding mechanical energy such as compression, friction, and collision to general scale-like graphite to spheroidize, Examples thereof include a method of granulating when producing artificial graphite.

  The apparent density of the graphite used in this specification is determined according to JIS-K-7365.

  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 Z 8901).

The specific surface area of the graphite used in the manufacture of extruded foam plate is preferably 1 to 10 m ² / g, more preferably 2 to 8 m ² / g.
The method of measuring the specific surface area can be measured by BET method using N ₂ adsorption.

  Moreover, the graphite used for manufacture of an extrusion foaming board has a small aspect-ratio. Specifically, the aspect ratio is preferably 3 or less, more preferably 2.5. The lower limit of the aspect ratio is 1.

As described above, graphite having a small aspect ratio and an average particle diameter within a specific range is not bulky and has a high apparent density. Since the efficiency of acting as a bubble nucleus is poor, it is considered that bubbles are difficult to be miniaturized. In addition, graphite with a small aspect ratio has a shape close to a sphere with no sharp parts, and thus it is considered that bubbles are difficult to break during bubble growth. As a result, it is considered that even when the graphite is added in a large amount, an extruded foam can be stably produced.
On the other hand, since general graphite such as scales has a high aspect ratio and is bulky, its apparent density is a small value. Since graphite having such a large aspect ratio tends to work as bubble nuclei, it is considered that it is likely to become bubble nuclei during foaming. Further, it is considered that general graphite easily breaks the bubbles during the growth of the bubbles because there is a pointed portion even if the average particle size is about the same as the graphite of the present invention. As a result, when a large amount of general graphite such as flakes is added, it becomes difficult to stably obtain an extruded foam having a low apparent density.

The aspect ratio in the present specification is obtained as follows.
The arbitrarily dispersed graphite was magnified with a scanning electron microscope, etc., and the number average of the “major axis length” / “minor axis length” of the 50 graphite particles randomly selected from the photograph was obtained. The value is taken as the aspect ratio. For scale-like graphite, the aspect ratio is calculated with the thickness direction as the minor axis. As conventional graphite is granulated and spheroidized, the directionality is lost. In this case, the aspect ratio is calculated from the lengths of the major axis and the minor axis as described above.

In addition, when a large amount of general graphite such as flaky graphite is added, the blackness of the resulting extruded foam plate increases, so that if it is left outdoors for a long time, the extruded foam plate heats up or the extruded foam plate Deformation or deterioration may occur. In contrast, even if a large amount of the graphite used in the present invention is added, the extruded foamed plate is not made strong black, and an extruded foamed plate with reduced whiteness can be obtained. Since the extruded foam plate stores heat or becomes black, the extruded foam plate is prevented from being deformed or deteriorated, and therefore has excellent dimensional stability after extrusion foaming.
In addition, the whiteness in this specification is a degree representing “whiteness” defined in ASTM E313.

  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 M 8511 (2005).

  Furthermore, the extruded foam plate containing the specific graphite exhibits a specific property that the oxygen index value becomes a substantially constant value even if the amount of graphite increases, although the reason is not clear. In the conventional general low apparent density graphite, the oxygen index value decreases as the addition amount increases, but the extruded foam plate added with the high apparent density graphite used in the present invention increases the addition amount of graphite. However, the oxygen index value does not decrease. For this reason, even if the graphite is added to the extruded foam plate in a larger amount than general graphite, it is possible to obtain an extruded foam plate having excellent thermal conductivity while maintaining flame retardancy.

  In this invention, the addition amount (X) of the said graphite is 0.5-8 weight part with respect to 100 weight part of said base resin. If the amount added is too small, the desired heat insulation property may not be exhibited. On the other hand, the graphite used in the present invention is less likely to inhibit foaming and flame retardancy compared to general scale-like graphite, so it can be added in a larger amount than general graphite. However, if the amount added is too large, the moldability and flame retardancy (JIS A 9511) when forming into a plate shape may be deteriorated. From this viewpoint, the added amount is preferably 1 to 7 parts by weight, and more preferably 2 to 6 parts by weight.

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

  The average particle diameter of the aluminum powder is 5 to 50 μm. If it is in the said range, even if it adds a little quantity, infrared rays are efficiently diffused efficiently and a favorable foamed board can be obtained. 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 aluminum powder can effectively irregularly reflect infrared rays with a small amount of addition, compared with other inorganic particles represented by titanium oxide. The addition amount (Y) of the aluminum powder is 0.15 to 1.5 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 the addition amount is too large, the aluminum powder acts as a nucleating agent, so that bubbles are excessively refined and foam moldability may be deteriorated. 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. From the above viewpoint, the content is preferably 0.2 to 1.0 part by weight.

  In the method of the present invention, the specific graphite and the specific aluminum powder are supplied as additives to the extruder together with the base resin and the like. By combining the graphite and the aluminum powder, the aluminum powder irregularly reflects infrared rays, and the graphite can efficiently absorb the irregularly reflected infrared rays. That is, it becomes possible to specifically and efficiently absorb infrared rays as compared with the case where each is used alone, and the amount of each compound can be reduced. 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. Further, since the foamed plate is made of graphite with a high apparent density, blackening is suppressed, and even if it is added in a larger amount than general scale-like graphite, bubbles in the foam are broken. In particular, the specific aluminum powder can effectively diffuse the infrared rays with a small amount of addition.

  In the method of the present invention, the ratio (X / Y) of the addition amount (X) of the graphite to the addition amount (Y) of the aluminum powder is preferably 1 or more, more preferably 3 or more. The upper limit of the ratio (X / Y) is approximately 20, preferably 15. If it is in the said range, a graphite can fully absorb the infrared rays which aluminum powder irregularly reflected, and the favorable thermal conductivity reduction effect is acquired.

As a method of blending the graphite and aluminum powder into the base resin, a predetermined amount of graphite and 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. The method of knead | mixing and mix | blending in molten base resin is mentioned. Alternatively, a master batch in which 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 the base resin to obtain a molten styrene resin mixture. 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 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.
In addition, since it becomes possible to suppress the fall of an oxygen index by using the said specific graphite, if the compounding quantity of a flame retardant is in the said range, the conventional difficulty which does not contain a graphite and an inorganic type particle | grain. Even if the amount is less than the amount of the flame retardant, it is possible to maintain the flame retardancy of the extruded foam plate at the same level as before.

  Furthermore, in the present invention, for the purpose of further improving the flame retardancy of the extruded foam plate, a small amount of 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 hydrofluoroolefin (HFO), aliphatic hydrocarbon having 3 to 5 carbon atoms, specifically, propane, normal butane, isobutane, normal pentane, isopentane, neopentane, and the like. And alicyclic hydrocarbons having 3 to 6 carbon atoms, 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 obtained by the method of the present invention will be described.
The extruded foam board of the present invention contains 0.5 to 8 parts by weight of graphite having an average particle diameter of 5 to 50 μm and an apparent density of 0.3 to 0.8 g / cm ³ with respect to 100 parts by weight of the base resin. In addition, 0.15 to 1.5 parts by weight of aluminum powder having an average particle diameter of 5 to 50 μm is contained with respect to 100 parts by weight of the base resin.

In extruded foam board of the present invention, an apparent density of 0.02~0.05g / cm ^3, 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, the thickness of this extrusion foaming board is 10-150 mm, 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.

  The average cell diameter in the thickness direction of the extruded foam plate is 0.08 to 0.8 mm, preferably 0.1 to 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 90% 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 in the above measurement (the volume of the resin composition constituting the cut sample of the extruded foamed plate (including particles (X), particles (Y), etc.)) And the total volume of bubbles in the closed cell portion in the cut 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 particles (X), particles (Y), etc.) constituting the extruded foam board

  As described above, the extruded foam plate of the present invention is excellent in heat insulating properties by containing specific amounts of specific 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. The oxygen index LOI according to −1 can be 26.0 or more, and more preferably the oxygen index LOI is 26.5 or more.

  The extruded foam board satisfying the oxygen index can be obtained by adjusting the blending amount of the hydrocarbon and the blending amount of the flame retardant. The extruded foam plate of the present invention contains the high apparent density graphite, and the graphite has a characteristic that it is difficult to lower the oxygen index. Moreover, if the amount of aluminum powder is also in the above range (0.15 to 1.5 parts by weight with respect to 100 parts by weight of the polystyrene resin), the oxygen index LOI is not lowered.

  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, and product names of styrenic resins used in Examples and Comparative Examples are shown in Table 1 below, the types of graphite, manufacturers, and product names are shown in Table 2 below, and the types, manufacturers, and product names of aluminum powder are shown in the table below. 3 shows.

  The flame retardant, bubble regulator, graphite, aluminum powder, 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 1-4, Comparative Examples 1-7, Reference Examples 1-4
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 addition, the addition amount [parts by weight] of the inorganic particles (graphite, aluminum powder), the flame retardant, and the air conditioner in Tables 4 and 5 is a value with respect to 100 parts by weight of the base resin, and the addition amount of the foaming agent [ Mol / 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

Comparative Examples 1 and 2 are examples in which only the graphite was contained in the foamed plate, and the obtained foamed plate did not contain aluminum powder, and thus the effect of reducing the thermal conductivity was small.

The comparative example 3 is an example which contains only aluminum powder in a foamed board, and since the obtained foamed board does not contain a graphite, the effect of reducing thermal conductivity was small.

Comparative Examples 4 and 5 are examples using graphite having an apparent density smaller than the range specified in the present invention even if it is graphite. A foamed plate with a high closed cell rate was not obtained.

Comparative Examples 6 to 8 are examples in which both the graphite and the aluminum powder are contained in the foamed plate, but the blending amount does not satisfy the range specifying the present invention. Since the foamed plate obtained in Comparative Example 6 contained too little aluminum powder, the thermal conductivity was insufficiently reduced despite the combined use of graphite. Since the foamed plate obtained in Comparative Example 7 contained too much aluminum powder, the foam moldability was poor and the closed cell ratio was low. Since the foamed plate obtained in Comparative Example 8 contained too little graphite and aluminum powder, the effect of reducing the thermal conductivity was insufficient.

Comparative Example 9 is an example in which the amount of graphite added is larger than the range specified in the present invention. In the foamed plate obtained in Comparative Example 9, since the amount of graphite added was too large, the air bubbles were excessively refined, and the foam moldability was deteriorated and a good foam molded article was not obtained. Evaluation was not performed.
The comparative example 10 is an example which does not contain both a graphite and aluminum powder in a foamed board.

  In the examples, comparative examples, and reference 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.
(Triangle | delta): A foaming state is bad and a foam cannot be obtained stably.
X: A foaming state is bad and a foam cannot be obtained.

(Flame retardant evaluation: Oxygen index LOI)
The oxygen index of the extruded foam plate was determined 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 A 9511)
The flame retardancy evaluation in Tables 4 and 5 is described in the measurement method A of JIS A 9511 (2006) 5.13.1 as a test piece cut out from a plate-like extruded foam after the lapse of 15 days after production. Evaluation was made in accordance with flammability standards for extruded polystyrene foam insulation board.
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 the 28 mm thick extruded foam plate), the test piece was used to comply with JIS A1412-2: 1999 described heat flow meter method (one specimen, symmetrical construction method), 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. A sample was cut out from the test piece so that the weight of the sample became 1 g 15 days after the production (corresponding to about 4 months after the extruded foam plate having a thickness of 28 mm). 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

(Graphite electron micrograph)
A sample of the extruded foam plate was dissolved in chloroform, and the precipitate was separated by ultracentrifugation. When the obtained precipitate contains a coloring material, dissolution with chloroform and ultracentrifugation were repeated until the coloring material contained in the precipitate was reduced. The obtained black precipitate was dried and photographed with a scanning electron microscope.

(Whiteness)
ASTM
In accordance with 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.

Claims (4)

A method for producing a polystyrene-based resin extruded foam plate, which comprises extruding and foaming a foamable resin melt obtained by kneading a base resin containing a polystyrene-based resin, a physical foaming agent, a flame retardant, graphite and aluminum powder,
The average particle diameter of the graphite is 5 to 50 μm, the apparent density is 0.3 to 0.8 g / cm ³ , and the amount (X) of the graphite added is 0.1% relative to 100 parts by weight of the base resin. 5-8 parts by weight,
The average particle diameter of this aluminum powder is 5-50 micrometers, and the addition amount (Y) of this aluminum powder is 0.15-1.5 weight part with respect to 100 weight part of said base resin, The polystyrene characterized by the above-mentioned. Of manufacturing a resin-based extruded foam board.
The method for producing a polystyrene-based resin extruded foam board according to claim 1, wherein the ratio (X / Y) of the addition amount (X) of the graphite to the addition amount (Y) of the aluminum powder is 1 or more. .
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 of 0.08 to 0.8 mm. The manufacturing method of the polystyrene-type resin extrusion foam board of Claim 1 or 2.
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 0.08 to 0.8 mm,
The polystyrene-based resin extruded foam plate contains graphite and aluminum powder and a flame retardant, and has an average particle diameter of 5 to 50 μm and an apparent density of 0.3 to 0.8 g / cm ³ . Content of the graphite is 0.5 to 8 parts by weight with respect to 100 parts by weight of the base resin of the polystyrene resin extruded foam plate,
The average particle diameter of the aluminum powder is 5 to 50 μm, and the content of the aluminum powder is 0.15 to 1.5 parts by weight with respect to 100 parts by weight of the base resin of the polystyrene resin extruded foam plate. A featured polystyrene-based extruded foam board.