JP2013221110A - Extruded styrene resin foam and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extruded styrene resin foam excellent in thermal insulating property and environmental compatibility.SOLUTION: An extruded styrene resin foam is obtained by extrusion foaming of a styrene resin composition, which is prepared by melt-kneading a polystyrene resin, a heat ray radiation inhibitor comprising black particles and white particles, and a foaming agent. In the extruded styrene resin foam, The total addition amount of the heat ray radiation inhibitor is 1 to 8 pts.wt. with respect to 100 pts.wt. of the polystyrene resin; an addition amount Y of the black particles is 0.5 to 5 pts.wt.; and an addition amount X of the white particles is 0.5 to 7 pts.wt. Further, a ratio (X/Y) of the addition amount X of the white particles to the addition amount Y of the black particles is less than 2, and the foaming agent does not include a halogen-containing compound.

Description

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

  Styrenic resin extruded foam is used as a heat insulating material for structures, for example, because of good workability and heat insulating properties. As a method for producing a styrene resin extruded foam, extrusion foam molding is known. This extrusion foam molding is performed by heating and melting a styrene resin composition using an extruder or the like, then adding a foaming agent, cooling to a predetermined resin temperature, and extruding it to a low pressure region to extrude a styrene resin. Is manufactured continuously. In recent years, from the viewpoint of reducing carbon dioxide emissions, there has been an increasing demand for energy saving in houses, buildings, and the like, and technical development of foams with higher heat insulation than ever before is desired.

  Various techniques have been proposed as techniques for improving the heat insulation properties of a foam using a thermoplastic resin. For example, a method of controlling the bubble shape and further the bubble diameter, such as a method of controlling the ratio of the bubble diameter in the extrusion direction (or the horizontal direction) to the bubble diameter in the thickness direction of the foam has been proposed (for example, Patent Documents). 1-3).

In addition, methods for adding additives such as carbon black, graphite, and titanium oxide have also been proposed (see, for example, Patent Documents 4 to 6). In particular, Patent Document 5 or 6 discloses a technique related to a foam that does not use chlorofluorocarbons, and discloses that heat insulation is improved by adding graphite or titanium oxide.
Furthermore, in order to prevent shape instability (warping due to solar radiation) due to a large amount of graphite, a method of using it together with titanium oxide has been proposed (for example, Patent Documents 7 to 8).

  However, in Patent Document 7, the amount of graphite used is limited to 0.3 to 2 parts by weight, and even when titanium oxide is used in combination, there is room for improvement in obtaining a foam with higher heat insulation properties. Further, in Patent Document 8, if a large amount of graphite is to be used, a large amount of titanium oxide must be added, causing problems such as unstable extrusion and poor appearance of the foam, and flame retardant of the foam. There is a problem that the performance decreases. Furthermore, Patent Documents 7 and 8 contain halogen-containing compounds such as methyl chloride and ethyl chloride as a foaming agent, and there is a problem that the foam has a high environmental load and a production method.

JP 2005-528494 A JP 2004-59595 A JP 2008-13659 A Japanese Patent Publication No. 4-502173 JP 2004-196907 A JP 2002-194129 A JP 2009-256426 A JP 2010-254780 A

  Under such circumstances, the problem to be solved by the present invention is to provide a styrene resin extruded foam having excellent heat insulation performance and excellent environmental compatibility, and a method for producing the same. .

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research, and as a result, in the production of styrene-based resin extruded foams, melted a polystyrene-based resin, a heat ray radiation inhibitor, and a foaming agent not containing a halogen-containing compound. It has been found that by extruding and foaming a styrene resin composition obtained by kneading, a foam having excellent heat insulation performance and excellent environmental compatibility can be obtained, and the present invention has been completed. .

That is, the present invention
[1] A styrene resin extruded foam obtained by extrusion foaming a styrene resin composition obtained by melt-kneading a polystyrene resin, a black particle and a white particle, and a foaming agent. And
The total addition amount of the heat ray radiation inhibitor is 1 to 8 parts by weight with respect to 100 parts by weight of the polystyrene resin, the addition amount Y of the black particles is 0.5 to 5 parts by weight, and the white particles The addition amount X is 0.5 to 7 parts by weight, and the ratio (X / Y) of the addition amount X of the white particles to the addition amount Y of the black particles is less than 2,
And it is a styrene-type resin extrusion foam characterized by this foaming agent not containing a halogen-containing compound.
[2] The black particles may be at least one selected from the group consisting of graphite, carbon black, and aluminum paste.
[3] The white particles include at least one selected from the group consisting of titanium oxide and barium sulfate.
[4] The black particles are preferably graphite.
[5] It is preferable that the fixed carbon content of the graphite is 75 to 90%.
[6] The graphite is at least one selected from the group consisting of scaly graphite and artificial graphite.
[7] The dispersed particle diameter of the graphite is preferably 15 μm or less.
[8] The foaming agent may be at least one selected from saturated hydrocarbons having 3 to 5 carbon atoms.
[9] The foaming agent further includes at least one selected from the group consisting of water, carbon dioxide, nitrogen, alcohols having 2 to 5 carbon atoms, and dimethyl ether.
[10] The thermal conductivity of the foam is preferably less than 0.0245 W / mK.
[11] The foam preferably has a density of 20 to 50 kg / m ³ and a thickness of 10 to 150 mm.
[12] Styrene obtained by extrusion foaming a polystyrene resin, a heat ray radiation inhibitor composed of black particles and white particles, and a styrene resin composition obtained by melt-kneading a foaming agent as a method for producing the foam A process for producing a resin-based extruded resin foam,
The total addition amount of the heat ray radiation inhibitor is 1 to 8 parts by weight with respect to 100 parts by weight of the polystyrene resin, the addition amount Y of the black particles is 0.5 to 5 parts by weight, and the white particles The addition amount X is 0.5 to 7 parts by weight, and the ratio (X / Y) of the addition amount X of the white particles to the addition amount Y of the black particles is less than 2,
And it is a manufacturing method of the styrene-type resin extrusion foam characterized by this foaming agent not containing a halogen-containing compound.

  ADVANTAGE OF THE INVENTION According to this invention, the styrene-type resin extrusion foam which has the outstanding heat insulation and was excellent also in environmental compatibility, and its manufacturing method are provided.

  Embodiments of the present invention will be described below. In addition, this embodiment is only a part of this invention, and it cannot be overemphasized that this embodiment can be suitably changed in the range which does not change the summary of this invention.

  The styrene resin used in the present invention is not particularly limited, and styrene monomers such as styrene, methyl styrene, ethyl styrene, isopropyl styrene, dimethyl styrene, bromo styrene, chloro styrene, vinyl toluene, and vinyl xylene are used alone. A copolymer consisting of a polymer or a combination of two or more monomers, the styrene monomer and divinylbenzene, butadiene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, acrylonitrile, maleic anhydride And a copolymer obtained by copolymerizing one or more monomers such as itaconic anhydride.

  Monomers such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, and itaconic anhydride to be copolymerized with styrenic monomers are the compression strength of the styrene resin extrusion foam produced The amount can be used so as not to deteriorate the physical properties.

  Further, the styrene resin used in the present invention is not limited to the homopolymer or copolymer of the styrene monomer, but the homopolymer or copolymer of the styrene monomer and the other single monomer. It may be a blend of the polymer with a homopolymer or copolymer, and may be blended with diene rubber reinforced polystyrene or acrylic rubber reinforced polystyrene. Furthermore, the styrene resin of the present invention is a styrene resin having a branched structure for the purpose of adjusting the melt flow rate (hereinafter referred to as “MFR”), the melt viscosity at the time of molding, the melt tension, and the like. Also good.

As the styrenic resin in the present invention, one having an MFR of 0.1 to 50 g / 10 min is excellent in molding processability at the time of extrusion foam molding, the discharge amount at the molding process, and the obtained thermoplasticity It is easy to adjust the thickness, width, density, or closed cell ratio of the resin foam to a desired value, and the foamability (the thickness, width, density, closed cell ratio, surface property, etc. of the foam is easily adjusted to the desired situation. Thermoplastic resin with a good balance of mechanical strength such as compressive strength, bending strength or amount of bending, and toughness, etc. It is preferable from the point that a foam is obtained.
Furthermore, the MFR of the styrenic resin is more preferably 0.3 to 30 g / 10 minutes, particularly 0.5 to 30 g / 10 minutes, from the viewpoint of the balance of molding processability and foaming mechanical strength, toughness and the like. preferable.
Here, in this invention, MFR is measured by A method and test condition H of JISK7210 (1999).

In the present invention, among the styrenic resins described above, a polystyrene resin can be particularly preferably used from the viewpoint of economy and processability. Further, when high heat resistance is required for the extruded foam, it is preferable to use a styrene-acrylonitrile copolymer, (meth) acrylic acid copolymer polystyrene, or maleic anhydride-modified polystyrene. Furthermore, when high impact resistance is required for the extruded foam, it is preferable to use rubber-reinforced polystyrene.
These styrenic resins may be used alone, and if the weight average molecular weight is 2.4 × 10 ⁵ or more, different styrenic resins such as copolymer components, molecular weight and molecular weight distribution, branched structure, MFR, etc. May be used in combination of two or more.

  The foaming agent used in the present invention is not particularly limited except that it does not contain a halogen-containing compound, but imparts excellent heat insulating properties by using a saturated hydrocarbon having 3 to 5 carbon atoms. be able to.

  Examples of the saturated hydrocarbon having 3 to 5 carbon atoms used in the present invention include propane, n-butane, i-butane, n-pentane, i-pentane, neopentane and the like. Among these saturated hydrocarbons having 3 to 5 carbon atoms, propane, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of foamability. Moreover, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of the heat insulating performance of the foam, and i-butane is particularly preferable.

  In the present invention, by using another foaming agent, a plasticizing effect and an auxiliary foaming effect at the time of foam production can be obtained, the extrusion pressure can be reduced, and the foam can be stably produced. However, depending on various properties of the foam, such as the desired foaming ratio and flame retardancy, the amount used may be limited, and the extrusion foam moldability may not be sufficient.

Examples of the blowing agent other than the saturated hydrocarbon having 3 to 5 carbon atoms include, for example, dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methyl furan, tetrahydrofuran, Ethers such as tetrahydropyran; dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl-n-butyl ketone, methyl-i-butyl ketone, methyl-n-amyl ketone, methyl-n-hexyl ketone, ethyl-n- Ketones such as propyl ketone and ethyl-n-butyl ketone; methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol, etc. Organic foaming agents such as saturated alcohols having a prime number of 1 to 4; formic acid methyl ester, formic acid ethyl ester, formic acid propyl ester, formic acid butyl ester, formic acid amyl ester, propionic acid methyl ester, propionic acid ethyl ester, etc. Inorganic foaming agents such as water and carbon dioxide, and chemical foaming agents such as azo compounds and tetrazole can be used.
These other blowing agents may be used alone or in combination of two or more.

  Among other foaming agents, from the viewpoint of foamability, foam formability, etc., saturated alcohols having 1 to 4 carbon atoms, dimethyl ether, diethyl ether, methyl ethyl ether, etc. are preferable. From the viewpoints of flame retardancy or heat insulation described later, water and carbon dioxide are preferred. Among these, dimethyl ether is particularly preferable from the viewpoint of the plasticizing effect, and water is particularly preferable from the viewpoint of the effect of improving the heat insulation by controlling the cost and the bubble diameter.

  In this invention, about the ratio of each foaming agent in the case of adding a plurality of foaming agents, the saturated hydrocarbon having 3 to 5 carbon atoms is 20 to 100% by weight, preferably with respect to the total weight of the foaming agent. It is 25 to 100% by weight, more preferably 30 to 100% by weight, and the other blowing agent is 0 to 80% by weight, preferably 0 to 75% by weight, more preferably 0 to 70% by weight. %. The other foaming agent is preferably 80% by weight or less in order to improve the heat insulation performance of the foam.

  The amount of the foaming agent used in the present invention is preferably 2 to 20 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the styrene resin. When the amount of the foaming agent used is less than 2 parts by weight, the expansion ratio is low, and the characteristics such as light weight and heat insulation as the resin foam may be difficult to be exhibited. Therefore, defects such as voids may occur in the foam.

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

  In the present invention, when water or alcohol is used as the other foaming agent, it is preferable to add a water-absorbing substance in order to stably perform extrusion foaming. Specific examples of water-absorbing substances used in the present invention include polyacrylate polymers, starch-acrylic acid graft copolymers, polyvinyl alcohol polymers, vinyl alcohol-acrylate copolymers, ethylene- In addition to water-absorbing polymers such as vinyl alcohol copolymers, acrylonitrile-methyl methacrylate-butadiene copolymers, polyethylene oxide copolymers and derivatives thereof, anhydrous silica (silicon oxide) having silanol groups on the surface [For example, AEROSIL manufactured by Nippon Aerosil Co., Ltd. is commercially available] Fine particle having a hydroxyl group on the surface and having a particle diameter of 1000 nm or less; Water-absorbing or water-swelling layered material such as smectite, swellable fluorine mica Silicates and their organic treated products: zeolite, activated carbon, alumina, silica Gel, porous glass, activated clay, porous substances such as diatomaceous earth and the like.

  The addition amount of the water-absorbing substance used in the present invention is appropriately adjusted depending on the addition amount of water and the like, but is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the styrenic resin. 0.1 to 3 parts by weight is more preferable.

In this invention, the foam which has high heat insulation and does not produce a deformation | transformation of the foam by heat storage is obtained by adding the heat ray radiation inhibitor which consists of black-type particle | grains and white-type particle | grains.
The heat ray radiation suppressing material in the present invention refers to a substance having a property of reflecting, scattering, and absorbing light in the near infrared or infrared region (for example, a wavelength region of about 800 to 3000 nm).

1-8 weight part is preferable with respect to 100 weight part of styrene resin, as for the total addition amount of the heat ray radiation inhibitor in this invention, 2-7 weight part is more preferable, and 3-6 weight part is further more preferable.
When the total addition amount of the heat ray radiation inhibitor is less than 1 part by weight, there is a tendency that high heat insulating properties cannot be obtained, and when it exceeds 8 parts by weight, the extrusion stability / formability is inferior or the combustibility is impaired. Tend.

Examples of the black particles used in the present invention include graphite, carbon black, activated carbon, and aluminum paste. These black particles may be used alone or in combination of two or more.
Among these black particles, graphite, carbon black, and aluminum paste are preferable, and graphite is particularly preferable because of its large effect of suppressing heat radiation.

  Examples of the graphite used in the present invention include scale-like (scale-like) graphite, artificial graphite, and earth-like graphite. Among these, it is preferable to use one or a mixture of those in which the main component is scaly graphite or artificial graphite because the effect of suppressing heat radiation is great.

  The fixed carbon content of the graphite used in the present invention is preferably 75 to 90%, more preferably 80 to 90%. By setting the fixed carbon content of graphite within the above range, a foam having high heat insulating properties can be obtained, and handling properties when handling graphite are facilitated.

The dispersion particle diameter of the black particles used in the present invention is not particularly limited. For example, carbon black is preferably 10 to 300 nm (0.01 to 0.3 μm), and 200 to 290 nm (0. 2 to 0.29 μm) is more preferable, and for graphite, 15 μm or less is preferable, and 10 μm or less is more preferable.
By setting the dispersed particle size of the black particles in the above range, the existence probability of the particles in the resin is increased, and the heat ray radiation suppressing effect is increased.
Here, the dispersed particle diameter is an arithmetic average value based on the number of the particle diameters of the respective black particles dispersed in the foam plate, and the dispersed particle diameter is measured with a microscope through a cross section of the foam plate. It is enlarged and measured by such as. The primary particle size means a volume average particle size (d50).

  By the way, in order to set the dispersed particle size within the above range, carbon black having a primary particle size of 300 nm or less and graphite having a primary particle size of 15 μm or less may be selected.

The addition amount Y of the black particles in the present invention is preferably 0.5 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and 1 to 3 parts by weight with respect to 100 parts by weight of the styrene resin. Further preferred.
When the added amount Y of the black particles is less than 0.5 parts by weight, there is a tendency that high heat insulating properties cannot be obtained. When the amount exceeds 5 parts by weight, the extrusion stability and formability are inferior, and the foam deforms due to heat storage. Tend to be larger.
However, in the present invention, the addition amount of the black particles is not determined independently, but is preferably determined in association with the addition amount of the white particles.

Examples of the white particles used in the present invention include titanium oxide, barium sulfate, zinc oxide, aluminum oxide, and antimony oxide. These white particles may be used alone or in combination of two or more.
Among these white particles, titanium oxide and barium sulfate are preferable, and titanium oxide is more preferable because the effect of suppressing heat radiation is large.

  The dispersed particle size of the white particles used in the present invention is not particularly limited. However, in view of effectively reflecting infrared rays and considering the color developability to the resin, for example, with titanium oxide, it is 0. 1 μm to 10 μm is preferable, and 0.15 μm to 5 μm is more preferable.

As addition amount X of the white type particle | grains in this invention, 0.5-7 weight part is preferable with respect to 100 weight part of styrene resin, 1-6 weight part is more preferable, and 2-5 weight part is further more preferable. .
If the addition amount X of the white particles is less than 0.5 parts by weight, there is a tendency that high heat insulating properties cannot be obtained. If it exceeds 7 parts by weight, the extrusion stability and moldability are inferior, and the flame retardancy of the foam Tend to get worse.
However, in the present invention, the addition amount of the white particles is not determined independently, but is preferably determined in association with the addition amount of the black particles.

In the present invention, the ratio (X / Y) of the addition amount X of the white particles to the addition amount Y of the black particles is preferably less than 2.
If X / Y is 2 or more, the presence probability of white particles having a heat radiation suppression effect inferior to that of black particles increases, and a large amount of heat radiation inhibitor is added to exert a sufficient heat radiation suppression effect. Must.

  In this invention, a flame retardance can be provided to the styrene resin foam obtained by containing a halogenated flame retardant as a flame retardant.

Specific examples of the halogen flame retardant in the present invention include, for example, halogenated alicyclic compounds such as hexabromocyclododecane, tetrabromocyclooctane, and chloropentabromocyclohexane; hexabromobenzene, pentabromotoluene, ethylenebispenta Bromodiphenyl, decabromodiphenyl ether, 2,3-dibromopropylpentabromophenyl ether, bis (2,4,6-tribromophenoxy) ethane, tetrabromophthalic anhydride, octabromotrimethylphenylindane, pentabromobenzyl acrylate, tribromo Halogenated aromatic compounds such as phenyl allyl ether or derivatives thereof; tetrabromobisphenol-A, tetrabromobisphenol-S, tetrabromobisphenol-F, Labromobisphenol-A-bis (2,3-dibromopropyl ether), tetrabromobisphenol-S-bis (2,3-dibromopropyl ether), tetrabromobisphenol-F-bis (2,3-dibromopropyl ether) Tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol-S-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol-F-bis Brominated bisphenols such as (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol-A-diallyl ether, tetrabromobisphenol-S-diallyl ether, tetrabromobisphenol-F-diallyl ether, and the like Conductor, and the like.
These substances may be used alone or as a mixture.

  Among these halogen flame retardants, hexabromocyclododecane, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, tetrabromobisphenol A-bis (2,3-dibromopropyl) ether, Tris (2,3-dibromopropyl) isocyanurate is preferred because it has a good extrusion operation and does not adversely affect the heat resistance of the foam.

The content of the halogen flame retardant in the present invention is such that the flammability specified in JIS A9511 can be obtained, and that the thermal stability of the styrene resin can be maintained in the extruder during foam production. Although it is appropriately adjusted according to the type of fuel, the amount of foaming agent added, the density of the foam, and depending on the case, the type or amount of other additives, it is generally 1 to 100 parts by weight of the styrene resin. 5 parts by weight is preferable, and 2 to 4.5 parts by weight is more preferable.
If the content of the halogen-based flame retardant is less than 0.2 parts by weight, good properties as a foam such as flame retardancy tend to be difficult to obtain. On the other hand, if the content exceeds 5 parts by weight, foam production The stability and surface properties of the time may be impaired.
However, the content of the flame retardant is such that the flame retardant specified in JIS A9511 measurement method A can be obtained, such as the amount of foaming agent added, the density of the foam, an additive having a flame retardant synergistic effect or the like. It is more preferable to adjust appropriately according to the above.

  In the present invention, for the purpose of improving the flame retardancy of the styrenic resin foam, a flame retardant aid exhibiting a synergistic effect with the flame retardant described above may be added. Examples of the flame retardant auxiliary that exhibits a synergistic effect with the flame retardant include iron-containing compounds, phosphorus-containing compounds, nitrogen-containing compounds, boron-containing compounds, sulfur-containing compounds, and the like, and specifically, iron oxide and phosphorus-containing compounds. , Nitrogen-containing compounds, boron-containing compounds, sulfur-containing compounds (aromatic sulfonic acid compounds), and the like may be used.

  Among these flame retardant aids, from the viewpoint of flame retardancy, iron oxide as the iron-containing compound, triphenyl phosphate and tris (tribromoneopentyl) phosphate as the phosphorus-containing compound, cyanuric acid and isocyanuric acid as the nitrogen-containing compound, and these Most preferred are derivatives, boron oxide as the boron-containing compound, sulfanilic acid as the sulfur-containing compound and derivatives thereof. In addition, as a cyanuric acid derivative and an isocyanuric acid derivative, the thing of Unexamined-Japanese-Patent No. 2002-30174 ([0069] paragraph-[0079] paragraph) can be used, for example.

  In the present invention, the content of the flame retardant aid exhibiting a synergistic effect with the halogen flame retardant depends on the type of the flame retardant aid exhibiting a synergistic effect with the halogen flame retardant, but is 0 with respect to 100 parts by weight of the styrene resin. 0.0001 to 5 parts by weight is preferred.

  In the present invention, various inorganic substances such as silica, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate and the like, as long as they do not inhibit the effects of the present invention. Compounds, processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, phenolic antioxidant, phosphorus stabilizer, nitrogen stabilizer, sulfur stabilizer It may contain additives such as a light-resistant stabilizer such as an agent, a benzotriazole, a hindered amine, a flame retardant other than the above, an antistatic agent, and a colorant such as a pigment.

  As a procedure for adding various additives to the styrenic resin in the present invention, for example, after adding and mixing various additives to the styrenic resin, the mixture is supplied to an extruder, heated and melted, and further a foaming agent is added. However, the timing of adding various additives to the styrene resin and the kneading time are not particularly limited.

  The heating temperature of the styrenic resin may be higher than the temperature at which the used styrenic resin is melted, but the temperature at which the molecular degradation of the resin due to the influence of additives and the like is suppressed as much as possible, for example, about 150 to 260 ° C. preferable. The melt-kneading time varies depending on the amount of styrene-based resin extruded per unit time and the type of extruder used as the melt-kneading means, so it cannot be uniquely defined. The styrene-based resin and the blowing agent or additive are uniform. The time required for the dispersion and mixing is appropriately set.

  Examples of the melt-kneading means include a screw type extruder, but are not particularly limited as long as they are used for ordinary extrusion foaming. However, in order to suppress the molecular deterioration of the resin as much as possible, the screw shape of the extruder is preferably a low shear type.

  The foam molding method is, for example, that an extruded foam obtained by opening from a high pressure region to a low pressure region through a slit die having a straight slit shape used for extrusion shaping is in close contact with or in contact with the slit. A method of molding a plate-like foam having a large cross-sectional area is used, using a molding die placed in the middle and a molding roll placed adjacent to the downstream side of the molding die. By adjusting the flow surface shape of the molding die and the mold temperature, the desired cross-sectional shape of the foam, the surface property of the foam, and the quality of the foam can be obtained.

  When considering that the styrene resin extruded foam according to the present invention functions as, for example, a heat insulating material for buildings, a cold storage or a cold car, the thermal conductivity measured according to JIS A9511 is 0. It is preferable that it is 028 W / mK or less.

The styrene-based resin extruded foam according to the present invention has a density of the foam from the viewpoint of heat insulation and lightness considering that it functions as, for example, a heat insulator for a building, a cold storage, or a cold car. is preferably 20 to 50 kg / ^{m 3,} more preferably from 25~45kg / ^{m 3.}

  The thickness of the styrene-based resin extruded foam according to the present invention is not particularly limited, but for example, heat insulation, bending strength, and compressive strength in consideration of functioning as a heat insulator for a building, a cold storage, or a cold car. From this viewpoint, the thickness is preferably 10 to 150 mm, more preferably 15 to 120 mm, and particularly preferably 20 to 100 mm.

  Thus, according to the present invention, it is possible to easily obtain a styrene resin extruded foam having excellent heat insulation and excellent environmental compatibility.

  Examples of the present invention will be described below. Needless to say, the present invention is not limited to the following examples. In the following examples and comparative examples, “%” represents “% by weight” unless otherwise specified.

The raw materials used in the examples and comparative examples are as follows.
(A) Styrenic resinPolystyrene [PS Japan Co., Ltd., 680]
(B) Heat ray radiation inhibitor (black particles)
Graphite A: Scale-like graphite [manufactured by Nishimura Graphite, PS-85 (primary particle size 10.5 μm, fixed carbon content 85%)]
Graphite B: Scale-like graphite [manufactured by Ito Graphite, X-10 (primary particle size 10 μm, fixed carbon content 98%)]
Graphite C: Soil-like graphite [manufactured by Nishimura Graphite, S fine powder (primary particle size 9.3 μm, fixed carbon content 80%)]
Graphite D: Scale-like graphite [manufactured by Nishimura Graphite, PB-85 (primary particle size 18.5 μm, fixed carbon content 85%)]
● Carbon black [Asahi Carbon Co., Ltd., SUNBLACK 250]
(C) Heat ray radiation inhibitor (white particles)
● Titanium oxide [R-7E, manufactured by Sakai Chemical Industry Co., Ltd.]
● Barium sulfate [manufactured by Sakai Chemical Industry Co., Ltd., BMH]
(D) Halogen-based flame retardant ● Flame retardant A: Hexabromocyclododecane [manufactured by Albemarle, HP900]
Flame retardant B: Tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl) ether [Pyroguard SR-130, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]
Flame retardant C: Tetrabromobisphenol-A-bis (2,3-dibromopropyl) ether [Daiichi Kogyo Seiyaku Co., Ltd., Pyroguard SR-720]
(E) Other additives
● Talc [Made by Hayashi Kasei Co., Ltd., Talcan Powder PK-Z]
● Calcium stearate [manufactured by Sakai Chemical Co., Ltd., SC-P]
● Bentonite [Wilver Ellis Co., Ltd., Gel White H]
● Aerosil “Nippon Aerosil Co., Ltd., AEROSIL]
(F) Foaming agent ● Isobutane [Mitsui Chemicals, Inc.]
● Dimethyl ether [manufactured by Sumitomo Seika Co., Ltd.]
● Methyl chloride [Shin-Etsu Chemical Co., Ltd.]
● Water [Settsu City tap water]

  About an Example and a comparative example, the foam density, the closed cell rate, the amount of residual foaming agents, the thermal conductivity, and the bubble diameter distribution were evaluated according to the following methods.

(1) Extrusion stability and moldability Stability and moldability during extrusion foaming when extruded and foamed continuously for 8 hours were evaluated according to the following criteria.
○: Almost no change in width and thickness, pressure in the mold, and fluctuation of the extruder motor current are observed in the obtained foam.
(Triangle | delta): The width | variety and thickness change, the pressure in a metal mold | die, and the fluctuation | variation of an extruder motor electric current are seen by the obtained foam.
X: The resulting foam has a large variation in width, thickness, pressure in the mold, and motor current of the extruder, making extrusion foam molding difficult.

(2) Environmental compatibility With regard to the foaming agent to be used, the case where no halogen-based foaming agent is used is “◯”, and the case where a halogen-based foaming agent is used is “x”.

(3) Whole foam density (kg / m ³ )
The obtained styrene-based resin extruded foam was cut into a rectangular parallelepiped shape having an extrusion (length) direction of 300 mm, a width direction of 100 mm, and a thickness direction of 30 mm, and the weight was measured, and the caliper [Mittoyo Corporation, M type standard Using a caliper N30], the length, width, and thickness were measured.
From the measured weight and each dimension, the foam density was calculated | required based on the following formula | equation, and the unit was converted into kg / m < ³ >.
Foam overall density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ )

(4) Bubble diameter The bubble diameter of the obtained styrene resin extruded foam was measured by a method based on ASTM D 3567.

(5) Thermal conductivity (W / mK)
The thermal conductivity of the foam was measured by a method based on JIS A1412-2: 1999.
In addition, this measurement was performed after one week passed at normal temperature after manufacturing a foam. Considering that the long-term thermal conductivity after 25 years satisfies 0.028 W / mK defined in JIS A 9511, the evaluation was made according to the following criteria.
○: Thermal conductivity is less than 0.0245 W / mK.
(Triangle | delta): Thermal conductivity is 0.0245 W / mK or more and less than 0.0280 W / mK.
X: Thermal conductivity is 0.0280 W / mK or more.

(6) Foam Combustibility The obtained sample was stored indoors, and the foam after 7 days from manufacture was measured according to JIS A9511.
○: Satisfies the criteria that the flame disappears within 3 seconds, there is no residue, and the combustion limit indicator line is not exceeded.
X: The above criteria are not satisfied.

Example 1
With respect to 100 parts by weight of polystyrene resin, 1.2 parts by weight of graphite A as a heat ray radiation suppressor, 2 parts by weight of titanium oxide, 4 parts by weight of flame retardant A as a flame retardant, and talc as a bubble diameter adjusting agent are set to 0.0. 3 parts by weight and 0.2 parts by weight of calcium stearate as a lubricant were dry blended.
40-50 kg of the obtained resin mixture into a tandem type two-stage extruder in which a 65 mm caliber single screw extruder (first extruder) and a 90 mm caliber single screw extruder (second extruder) are connected in series. / Hr.
The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 3.5 parts by weight of isobutane and 3 parts by weight of dimethyl ether are added to 100 parts by weight of polystyrene resin as a foaming agent. Was pressed into the resin in the vicinity of the tip. Then, while kneading in the second extruder connected to the first extruder, the resin temperature was cooled to 120 to 130 ° C., and then extruded and foamed into the atmosphere from the slit die provided at the tip of the second extruder. Thereafter, an extruded foam plate having a cross-sectional shape having a thickness of 40 mm and a width of 150 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.
The evaluation of extrusion stability / formability was “◯”, and the evaluation of environmental compatibility was “◯”. The resulting extruded foam had a density of 33 kg / m ³ , a cell diameter in the thickness direction of 0.15 mm, a thermal conductivity of 0.0248 W / mK, and an evaluation of “◯”. The flammability met JIS A9511 standards.

(Examples 2 to 12, Comparative Examples 1 to 5)
As shown in Table 1, a foam was obtained by the same operation as in Example 1 except that the types and amounts of various compounding agents were changed.
Table 1 shows the extrusion foaming stability and the properties of the obtained foam.

実施例１〜１２と比較例１〜５を比較して明らかなように、特定量の黒色系粒子と白色系粒子からなる熱線輻射抑制剤と、ハロゲン含有化合物を含まない発泡剤を溶融混練してなるスチレン系樹脂組成物を押出発泡して製造することにより、断熱性と環境適合性に優れた押出発泡体を安定して得られることが判る。

As is clear by comparing Examples 1 to 12 with Comparative Examples 1 to 5, a heat radiation inhibitor comprising a specific amount of black particles and white particles and a foaming agent not containing a halogen-containing compound are melt-kneaded. It can be seen that an extruded foam excellent in heat insulation and environmental compatibility can be obtained stably by extrusion foaming the styrene resin composition obtained.

Claims (12)

A polystyrene resin, a heat ray radiation inhibitor composed of black particles and white particles, and a styrene resin extruded foam obtained by extrusion foaming a styrene resin composition obtained by melt-kneading a foaming agent,
The total addition amount of the heat ray radiation inhibitor is 1 to 8 parts by weight with respect to 100 parts by weight of the polystyrene resin, the addition amount Y of the black particles is 0.5 to 5 parts by weight, and the white particles The addition amount X is 0.5 to 7 parts by weight, and the ratio (X / Y) of the addition amount X of the white particles to the addition amount Y of the black particles is less than 2,
The styrene resin extruded foam is characterized in that the foaming agent does not contain a halogen-containing compound.   The styrene resin extruded foam according to claim 1, wherein the black particles include at least one selected from the group consisting of graphite, carbon black, and aluminum paste.   The styrene resin extruded foam according to claim 1 or 2, wherein the white particles include at least one selected from the group consisting of titanium oxide and barium sulfate.   The styrene resin extruded foam according to any one of claims 1 to 3, wherein the black particles are graphite.   The styrene resin extruded foam according to claim 4, wherein the fixed carbon content of the graphite is 75 to 90%.   The styrene resin extruded foam according to claim 4 or 5, wherein the graphite contains at least one selected from the group consisting of scaly graphite and artificial graphite.   The styrene resin extruded foam according to any one of claims 4 to 6, wherein the dispersed particle diameter of the graphite is 15 µm or less.   The styrenic resin foam according to any one of claims 1 to 78, wherein the foaming agent contains at least one selected from saturated hydrocarbons having 3 to 5 carbon atoms.   The styrenic system according to claim 8, further comprising at least one selected from the group consisting of water, carbon dioxide, nitrogen, alcohols having 2 to 5 carbon atoms, and dimethyl ether as a foaming agent. Resin foam.   The styrenic resin extruded foam according to any one of claims 1 to 9, wherein the thermal conductivity is less than 0.0245 W / mK. The extruded foam according to claim 1, wherein the foam has a density of 20 to 50 kg / m ³ and a thickness of 10 to 150 mm. A method for producing an extruded foam of a styrene resin obtained by extrusion foaming a styrene resin composition obtained by melt-kneading a polystyrene resin, a black particle and a white particle, and a foaming agent. And
The total addition amount of the heat ray radiation inhibitor is 1 to 8 parts by weight with respect to 100 parts by weight of the polystyrene resin, the addition amount Y of the black particles is 0.5 to 5 parts by weight, and the white particles The addition amount X is 0.5 to 7 parts by weight, and the ratio (X / Y) of the addition amount X of the white particles to the addition amount X of the black particles is less than 2,
And the said foaming agent does not contain a halogen containing compound, The manufacturing method of the styrene-type resin extrusion foam characterized by the above-mentioned.