JP5849507B2 - Extruded foam with excellent heat insulation performance - Google Patents

Description

  The present invention relates to an extruded foam that is suitably used as a heat insulating material for buildings, cold storage, cold cars, and the like.

  Foams made of thermoplastic resins or thermosetting resins are widely used as heat insulating materials for buildings. From the viewpoint of reducing carbon dioxide emissions, demands for energy saving in housing and buildings are increasing, and further demand for heat insulating materials is expected.

  Among such heat insulating materials, hard polyurethane foams using chlorofluorocarbons as foaming agents have been widely used as foams having high heat insulating performance. However, from the viewpoint of protecting the global environment, development of foams that do not use chlorofluorocarbons as foaming agents has been advanced not only for rigid polyurethane foams but also for various foams.

  There has been proposed a foam using a thermosetting resin phenolic resin as a foam without using chlorofluorocarbons and having excellent heat insulation and little change with time (see, for example, Patent Document 1). It can be said that it is a foam having the most excellent heat insulating property among foams made of thermoplastic resin or thermosetting resin. However, from the viewpoint of further resource saving in addition to energy saving, its use is restricted from the viewpoint of so-called “recycling” that can be reused as a resin, and it cannot be said that it is widely used. is there.

  For this reason, it is desired to develop a technology for a foam that uses a recyclable thermoplastic resin and does not use chlorofluorocarbons and has a higher heat insulation than ever before.

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 adding an additive such as carbon black, graphite, or titanium oxide has also been proposed (see, for example, Patent Documents 1 to 3). In particular, Patent Document 2 or 3 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.
As described above, various techniques for improving the heat insulation property of the foam using the thermoplastic resin have been disclosed. However, in the technique that does not use the chlorofluorocarbons, the heat insulation property deteriorated due to the conversion of the foaming agent from the chlorofluorocarbons. There are many technologies aimed at supplementing

  As a technique that may further improve the heat insulation, a coextruded foam composite in which a foam layer and a non-foam layer are alternately laminated by a co-extrusion method may be mentioned. For example, a method of adding an additive such as carbon black to a coextruded foam composite has been proposed (see, for example, Patent Document 4 or 5). However, only the effects of foams using chlorofluorocarbons are exemplified.

  On the other hand, in order to obtain a foam having low thermal conductivity and excellent heat insulation, as a foaming agent, the thermal conductivity as a gas is low, and the permeability to a thermoplastic resin such as a styrene resin is low, that is, It is necessary to use a compound that is difficult to escape from the bubbles of the foam and difficult to dissipate.

  However, in general, the styrene resin foam has high permeability to the styrene resin, and air having higher thermal conductivity than the aliphatic hydrocarbon or halogenated hydrocarbon used as the blowing agent, It enters into the bubbles of the foam relatively soon after production. Even aliphatic hydrocarbons and halogenated hydrocarbons having low permeability to styrene resins gradually dissipate from the foam. Therefore, there is a problem that the thermal conductivity of the styrenic resin foam itself is gradually increased, and the heat insulating property is gradually decreased.

For example, Patent Document 6 discloses a technique for suppressing heat ingress and improving heat insulation by using a nitrile resin having low gas permeability.
However, an extruded foam using a nitrile resin is difficult to combine with other conventional techniques for improving the thermal insulation of the foam, such as cell structure control in an extruded foam mainly composed of styrene. Furthermore, there is a drawback that the foam is brittle.

  On the other hand, in producing an extruded foam, when an extruded foam having a skin layer is produced, there is a limitation in producing an extruded foam having good thickness accuracy and surface properties. Further, since the density of the skin layer is high, the density of the entire extruded foam is increased, which is disadvantageous in terms of cost.

  For example, in Patent Document 7, in a styrene resin extruded foam having a skin layer, by adjusting the density of the skin layer relative to the entire density of the extruded foam and the extrusion mold temperature relative to the Vicat softening point temperature of the styrene resin. A technique for producing an extruded foam excellent in thickness accuracy and surface properties is disclosed. However, an extruded foam without a skin layer is superior in thickness accuracy and easy to reduce the overall density.

  In this way, in the co-extrusion foamed composite, high heat insulation foam without using chlorofluorocarbons, and high heat insulation foam such as foam using phenol resin and rigid polyurethane foam using chlorofluorocarbons. No technology aimed at gaining a body has been proposed yet.

Japanese Patent Publication No. 4-502173 JP 2004-196907 A JP 2002-194129 A Japanese National Patent Publication No. 6-510247 Japanese Patent Laid-Open No. 5-577779 JP 2007-154006 A JP 2010-138244 A

  The present invention solves the above-mentioned problems, is a foam made of a thermoplastic resin, has a significant effect of improving the heat insulation performance without using chlorofluorocarbons as a foaming agent, and has low thermal conductivity An object of the present invention is to provide an extruded foam for a heat insulating material that has a low rate of change with time.

As a result of intensive studies to solve the above-mentioned problems, the present inventor found the following matters and completed the present invention.
(1) As a foam structure, an alternately laminated structure of a foam layer (A) and a non-foam layer (B) is used, and the resin constituting (B) has a lower air permeability than the resin constituting (A) By containing at least one of these, the heat insulating property of the extruded foam and its change with time are further improved.
(2) Furthermore, by manufacturing this using a coextrusion method, the non-foamed layer suppresses the intrusion of air into the foamed layer cell that occurs immediately after the production.
(3) Excellent thickness accuracy by cutting the skin layer.
(4) Further, by having two or more non-foamed layers (B), even if the skin layer is cut, the heat-insulating change with time equal to or greater than that of the extruded foam with a skin layer is maintained.

That is, the present invention
[1] An extruded foam having a plurality of structures in which a foam layer (A) is laminated in the thickness direction via a non-foam layer (B), and having no skin layer,
In the non-foamed layer (B), in accordance with JIS K7126 (2006), the temperature is 23 ° C. and the relative humidity is 0% R.D. H. Containing at least one resin whose air permeability measured under conditions is lower than the resin constituting the foam layer (A), and
In the resin that has at least two layers of the non-foamed layer (B), has no skin layer, and the resin that constitutes the foamed layer (A) is a styrenic resin, and that constitutes the non-foamed layer (B), An extruded foam comprising at least one selected from the group consisting of a nitrile resin and a styrene-unsaturated nitrile copolymer resin,
[2] The extruded foam according to [1], wherein the nitrile-based resin contains 50% by weight or more of a unit derived from an unsaturated nitrile monomer in the molecule,
[3] The nitrile resin is a nitrile resin obtained by graft copolymerization of an unsaturated nitrile and a (meth) acrylic acid alkyl ester in the presence of a conjugated diene rubber-like polymer. [1] Or the extruded foam according to [2],
[4] The styrene-unsaturated nitrile copolymer resin contains 1% by weight or more and less than 50% by weight of units derived from an unsaturated nitrile monomer in the molecule, and a unit derived from a styrene monomer. The extruded foam according to any one of [1] to [3], characterized by containing 50% by weight or more and less than 99% by weight,
[5] The resin constituting the non-foamed layer (B) contains a nitrile resin, at least one resin selected from the group consisting of a styrene-unsaturated nitrile copolymer resin and a styrene resin. The extruded foam according to any one of [1] to [4],
[6] The resin constituting the non-foamed layer (B) is 0.5 to 80% by weight of a nitrile resin and at least one selected from styrene resin and styrene-unsaturated nitrile copolymer resin 20 to 99. The extruded foam according to any one of [1] to [5], comprising 5% by weight,
[7] The resin constituting the non-foamed layer (B) is composed of 0.5 to 80% by weight of a nitrile resin and 20 to 99.5% by weight of a styrene-unsaturated nitrile copolymer resin, The extruded foam according to any one of [1] to [6],
[8] When the resin constituting the non-foamed layer (B) is 100% by weight as a whole, nitrile resin 0.5 to 80% by weight, styrene-unsaturated nitrile copolymer resin 0.5 to 80% by weight And the extruded foam according to any one of [1] to [6], comprising 19.5 to 99% by weight of a styrene resin,
[9] The extruded foam according to any one of [1] to [8], wherein the density of the extruded foam is 20 to 100 kg / m ³ .
[10] The bubbles constituting the foam layer contain at least one hydrocarbon compound selected from the group consisting of propane, n-butane, i-butane and cyclopentane, 1] to [9], the extruded foam according to any one of
[11] The extruded foam according to any one of [1] to [10], which is for a heat insulating material,
[ 12 ] A method for producing an extruded foam having a plurality of structures in which a foam layer (A) is laminated via a non-foam layer (B) in the thickness direction, and having no skin layer,
After the molten resin containing the foaming agent and the molten resin not containing the foaming agent are merged in the thickness direction under high pressure, it is released under atmospheric pressure, and
According to JIS K7126 (2006), a molten resin containing no foaming agent has a temperature of 23 ° C. and a relative humidity of 0% R.P. H. Containing at least one resin lower than the molten resin containing the foaming agent in the air permeability measured under the conditions; and
In the resin that has at least two non-foamed layers (B), removes the skin layer, and the resin that constitutes the foamed layer (A) is a styrene resin, and that constitutes the non-foamed layer (B) A process for producing an extrusion foamed molded article comprising at least one selected from the group consisting of a nitrile resin and a styrene-unsaturated nitrile copolymer resin , and
[13] The method for producing an extruded foam molded article according to [12], wherein the extruded foam molded article is an extruded foam molded article for a heat insulating material .

The effects of the extruded foam of the present invention are as follows.
-As a foam structure, the foamed layer (A) has a laminated structure in which the foamed layer (A) is laminated via the non-foamed layer (B), and in a specific density range, the resin constituting (B) constitutes (A) By containing at least one resin having a lower air permeability than the resin to be used, the intrusion of air from the outside air into the foam layer cell is suppressed, the heat insulation of the foam is further improved, and the time Change can be improved more.
-By producing an extruded foam having a laminated structure in which a foamed layer and a foamed layer are laminated via a non-foamed layer using a coextrusion method, air in the foamed layer cell generated immediately after production is produced. Invasion can be suppressed by the non-foamed layer, and in particular, by taking a structure in which both sides of the foamed layer are covered with the non-foamed layer in the thickness direction, infiltration of air from the outside air into the foamed layer cell is suppressed, The heat insulation performance of the resulting foam can be further improved.
-By having two or more non-foamed layers (B), even if the skin layer is cut, it is possible to maintain the same time or better thermal insulation change as the extruded foam with the skin layer, and the thickness accuracy without the skin layer In the extruded foam excellent in heat resistance, it is possible to suppress a change in heat insulation with time.
・ By using a foam having a laminated structure of a foamed layer and a non-foamed layer, and controlling the air permeability of the non-foamed layer, it is a conventional foam that only controls air permeability. Compared with the case, the heat insulating property is further improved, and this exhibits an effect which is not suggested at all by the prior art related to the conventional foamed composite.
Since the effect of the extruded foam can be combined with other conventional techniques aimed at improving the heat insulation of the foam, provision of a foam having an unprecedented heat insulation performance can be expected.

FIG. 1 is an example of an SEM photograph in an extruded cross section regarding a laminated structure of an extruded foam molded body according to the present invention.

  In the extruded foam of the present invention, the foamed layer (A) has a structure in which the foamed layer (A) is laminated via the non-foamed layer (B) in the thickness direction, and the resin constituting the non-foamed layer (B) is the foamed layer. By containing at least one resin having a lower air permeability than that of the resin constituting (A), it is possible to obtain a foam having higher heat insulation than that of a conventional extruded foam.

The foam layer (A) constituting the extruded foam of the present invention refers to a layer having a cell structure in which a plurality of cells are combined by cell walls and cell wall joints (struts). The shape is not particularly limited, and examples include a film shape, a sheet shape, and a board shape. Among these, a sheet shape and a board shape are more likely to exhibit heat insulation performance and can give light weight to the extruded foam. Is preferred. The density of the foam layer is preferably 500 kg / m ³ or less, although it depends on the density of the target extruded foam.

The non-foamed layer (B) constituting the extruded foam molded body of the present invention has a thickness of 1.1 times or more than the thicker portion of the bubble wall or bubble wall bonding portion of the bubble constituting the foam layer. It is a layer and refers to a layer having a higher density than the foamed layer constituting the periphery of the non-foamed layer. The density of the non-foamed layer depends on the density of the resin and additives used, but is preferably more than 500 kg / m ³ . The non-foamed layer may contain fewer bubbles than the foamed layer.

The density of the extruded foam of the present invention is preferably 20 to 100 kg / m ³ because a lightweight and highly heat-insulating foam is obtained, and 20 to 50 kg / m from the viewpoint of achieving both lightness and heat insulation. ³ is more preferable, and 20 to 40 kg / m ³ is more preferable.

  In the extruded foam of the present invention, since there is no skin layer, it becomes excellent in thickness accuracy and surface properties, and it becomes easy to reduce the density of the entire foam.

The “skin layer” in the present invention is within 2 mm from the surface of the extruded foam in the thickness direction, the density is 5 to ³⁰ kg / m ³ or more heavier than the density of the entire extruded foam, and includes the non-foamed layer (B) There are no layers.
Here, the density of the skin layer is obtained by the following equation, and the unit can be converted to kg / m ³ .
Skin layer density (kg / cm ³ ) = skin layer weight (g) / skin layer volume (cm ³ )
For example, a skin layer having a thickness of 2 mm, a width of 100 mm, and a length of 100 mm can be cut out in the thickness direction from the top and bottom surfaces at the center in the width direction of the extruded foam, and the density and volume can be measured.

In normal extrusion foaming, the surface area of the extruded foam comes into contact with the extrusion mold, so that the temperature of the extruded foam becomes lower than that of the part not in contact with the inside. A skin layer that is heavier than the density of 5 kg / m ³ is formed.

  In the present invention, “there is no skin layer” means that the skin layer is removed by, for example, using a vertical slicer, by cutting off both the upper and lower surfaces from the surface of the extruded foam to a thickness of more than 2 mm. It is.

  Examples of the cutting device used for removing the skin layer of the present invention include a vertical slicer, an NC router, a running saw, a panel saw, a heat ray slicer, etc., but the operation is simple and the extruded foam surface is affected by heat. A vertical slicer is preferable from the viewpoint of few.

  The resin or resin composition constituting the non-foamed layer (B) in the present invention (hereinafter sometimes referred to as “non-foamed layer (B) constituting resin”) has a desired low thermal conductivity and changes over time. In order to obtain a few extruded foams, the non-foamed layer constituting resin is a resin constituting the foamed layer (A) in the extruded foam of the present invention (hereinafter sometimes referred to as “foamed layer (A) constituting resin”). It is necessary to contain at least one kind of resin having a lower air permeability. When the non-foamed layer (B) constituent resin does not contain one or more resins having a lower air permeability than the foamed layer (A) constituent resin, the resulting extruded foam does not have the non-foamed layer (B). Similar to the extruded foam, since rapid air intrusion into the extruded foam occurs, the intended low thermal conductivity tends not to be maintained.

  Here, as the air permeability in this specification, a value obtained by measurement in accordance with JIS K 7126 (2006), which is a standard defined for gas permeability, is employed.

  The resin constituting the foamed layer (A) of the extruded foam of the present invention is arbitrarily selected from thermoplastic resins that can be extruded and foamed. The thermoplastic resin is not particularly limited, and for example, styrene resins such as polystyrene, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer; or polymethyl methacrylate, poly Vinyl resins such as vinyl chloride resins; styrene- (meth) acrylonitrile copolymers containing from 1% by weight to less than 50% by weight of units derived from unsaturated nitrile monomers (hereinafter referred to simply as “styrene- (meth)”) Styrene-unsaturated nitrile copolymer resin such as “acrylonitrile copolymer”; styrene- (meth) acrylonitrile copolymer containing 50% by weight or more of units derived from unsaturated nitrile monomer Nitrile resins such as acrylonitrile-alkyl acrylate-butadiene copolymers; polypropylene, polyethylene Polyolefin resins such as len, ethylene-propylene copolymer, ethylene-propylene-butene terpolymer and cycloolefin (co) polymer, and resins having a rheology controlled by introducing a branched structure and a crosslinked structure therein. Polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, and MXD nylon; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyarylate; polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins Engineering for polyoxymethylene resins, polyphenylene sulfide resins, polyphenylene sulfide resins, aromatic polyether resins, polyether ether ketone resins, liquid crystal resins, etc. Plastic; and aliphatic polyester resins such as polylactic acid and the like, which may be used alone or in combination.

  Among these, a styrene resin, a styrene-unsaturated nitrile copolymer resin, and a modified polyphenylene ether resin are preferable from the viewpoint of obtaining an extruded foam that is more easily extruded and foamed, lightweight, and excellent in heat insulation. . Most preferred is a styrene homopolymer because of its lower cost.

  When a styrene resin is used as the resin constituting the foamed layer (A) of the extruded foam of the present invention, for example, a styrene homopolymer obtained only from a styrene monomer, or copolymerizable with a styrene monomer and styrene And random, block or graft copolymers obtained from various monomers or derivatives thereof, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, ABS resin and the like. These can be used alone or in admixture of two or more.

  Examples of monomers copolymerizable with styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate and ethyl methacrylate, diene compounds such as budadiene or derivatives thereof , Maleic anhydride, itaconic anhydride, unsaturated carboxylic anhydrides such as citraconic anhydride, N-methylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-4- Phenylmaleimide, N-2-chlorophenyl maleimide, N-4-bromophenyl maleimide, N- alkyl-substituted maleimide compounds such as N-1- naphthyl maleimide; and the like. These can be used alone or in admixture of two or more.

  Non-foamed layer (B) constituent resins used in the present invention include, for example, nitrile resins, styrene-unsaturated nitrile copolymer resins, styrene resins, vinyl resins, polyester resins, polycarbonate resins, and engineering plastics. , Aliphatic polyester resins, and the like. These may be used alone or in combination of two or more, but contain at least one resin having a lower air permeability than the resin constituting the foam layer (A). There is a need.

  When a styrene resin is used as the constituent resin species for the foam layer (A), the non-foam layer (B) constituent resin contains at least one resin selected from a nitrile resin and a styrene-unsaturated nitrile copolymer resin It is preferable to do.

  The nitrile resin used as the constituent resin of the non-foamed layer (B) of the present invention is mainly composed of an unsaturated nitrile such as acrylonitrile containing 50% by weight or more of a unit derived from an unsaturated nitrile monomer. It is a polymer. Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. Of these, acrylonitrile and methacrylonitrile are preferred.

  The nitrile resin used as the non-foamed layer (B) constituent resin of the present invention is not particularly limited except that it contains 50% by weight or more of units derived from unsaturated nitrile monomers. Specific examples include a resin obtained only from a monomer, an unsaturated nitrile monomer, a monomer copolymerizable with an unsaturated nitrile, or a random, block or graft copolymer obtained from a derivative thereof.

  Examples of monomers copolymerizable with unsaturated nitriles include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Styrene derivatives other than styrene, polyfunctional vinyl compounds such as divinylbenzene, diene compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, and budadiene or derivatives thereof, itacon Polymerizable unsaturated fatty acids such as acid, maleic acid, fumaric acid, crotonic acid, cinnamic acid, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropylmale , N-phenylmaleimide, NP-bromophenylmaleimide, N-O-chlorophenylmaleimide, N-cyclohexylmaleimide and other maleimide acids, maleic anhydride, itaconic anhydride, citraconic anhydride and other unsaturated carboxylic acid anhydrides Products, epoxy group-containing unsaturated compounds such as allyl glycidyl ether, glycidimethacrylate, allylamine, aminoethyl methacrylate-aminopropyl, amino group-containing unsaturated compounds such as aminostyrene, acrylamide, N-methyl Examples include acrylamide-based compounds such as acrylamide, and hydroxyl-containing unsaturated compounds such as 2-hydroxyethyl-acrylate, 3-hydroxypropyl methacrylate, and 4-hydroxy-2-butene. These may be used alone or in combination of two or more.

  Of the nitrile resins, nitrile resins that can be melted at the processing temperature of the styrene-unsaturated nitrile copolymer resin described later are preferable. As such a nitrile resin, graft copolymerization of unsaturated nitrile, (meth) acrylic acid alkyl ester, and other copolymerizable monomers as required in the presence of a conjugated diene rubber-like polymer The nitrile resin obtained by doing this is mentioned.

  The conjugated diene rubbery polymer is selected from 50% by weight or more of conjugated diene and monomers copolymerizable therewith, such as unsaturated nitriles, aromatic vinyl compounds other than styrene, unsaturated carboxylic acid esters, and the like. Further, a copolymer with at least one monomer is preferable.

  Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, and the like. From the viewpoint of good polymerizability, 1,3-butadiene and isoprene are preferable. Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like, and acrylonitrile and methacrylonitrile are preferable.

  Examples of aromatic vinyl compounds other than styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, and other styrene derivatives, divinylbenzene. And polyfunctional vinyl compounds.

  As unsaturated carboxylic acid ester, acrylic acid such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, Examples include alkyl esters of methacrylic acid. Preferred are methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate.

  Specific examples of the conjugated diene rubber-like polymer include 1,3-butadiene-acrylonitrile copolymer, 1,3-butadiene-acrylonitrile-methacrylonitrile copolymer, 1,3-butadiene-acrylonitrile-styrene copolymer. Examples thereof include 1,3-butadiene-styrene copolymer. 1,3-butadiene-acrylonitrile copolymer and 1,3-butadiene-styrene copolymer are preferable. The conjugated diene rubbery polymer in 100% by weight of the nitrile resin is preferably 3 to 30% by weight.

  Monomers used for graft copolymerization in the presence of conjugated diene rubbery polymers include unsaturated nitriles, (meth) acrylic acid alkyl esters, and other monomers copolymerizable with these if necessary. It is preferable to use a monomer. Among these, it is more preferable to use unsaturated nitrile and (meth) acrylic acid alkyl ester.

  Examples of the unsaturated nitrile used as the graft monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. Of these, acrylonitrile and methacrylonitrile are preferred. The unsaturated nitrile is preferably contained in an amount of 50% by weight or more in 100% by weight of the monomer used for graft copolymerization, from the viewpoint of the heat insulating property of the obtained extruded foam. More preferably, it is 55 to 90% by weight.

  Examples of the (meth) acrylic acid alkyl ester used as the graft monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Methyl (meth) acrylate and ethyl (meth) acrylate are preferred. In 100% by weight of the monomer used for the graft copolymerization, it is preferable that the (meth) acrylic acid alkyl ester is contained in an amount of 3 to 50% by weight from the viewpoint of molding processability and heat insulation of the obtained extruded foam. More preferably, it is 5 to 40% by weight.

  Examples of other copolymerizable monomers include aromatic vinyl compounds other than styrene, vinyl ethers, vinyl esters, and α-olefins. As aromatic vinyl compounds other than styrene, methyl styrene, vinyl toluene, vinyl xylene, etc., as vinyl esters, vinyl acetate, propion vinyl, vinyl butyrate, etc., as vinyl ethers, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether , Methyl isopropenyl ether, ethyl isopropenyl ether, etc., as the α-olefin, isobutene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, 2-methyl-1- Examples include heptene, 2-methyl-1-octene, 2-ethyl-1-butene, and 2-propyl-1-butene. In 100% by weight of the monomer used for graft copolymerization, the other copolymerizable monomer is preferably contained in an amount of 0 to 20% by weight. If it is 20% by weight or less, it can be used according to the purpose without affecting the characteristics of the resulting nitrile resin.

  In the presence of a conjugated diene rubber-like polymer, the polymerization method of nitrile resin obtained by graft copolymerization with unsaturated nitrile, (meth) acrylic acid alkyl ester, and other copolymerizable monomers as required is emulsified. Known polymerization methods such as polymerization, solution polymerization, suspension polymerization, bulk polymerization, or a combination thereof can be applied. However, emulsion polymerization is preferably applied in consideration of ease of removal of polymerization heat, ease of post-treatment after polymerization, simplification of incidental facilities such as recovery and regeneration of organic solvents, and the like.

  In the case of the emulsion polymerization method, since the polymer product is obtained in a latex form, the polymer is coagulated and separated by a conventionally known method, for example, an aggregation method using an electrolyte or a solvent, or a freezing method. A method for obtaining a polymer by drying is raised. There is no restriction | limiting in particular in the temperature of graft polymerization, It can implement at arbitrary temperature of 0-100 degreeC. Considering the polymerization rate, conversion rate, productivity and the like, a temperature range of 30 to 70 ° C. is preferable. Moreover, it is also possible to add a plasticizer, a stabilizer, a lubricant, a dye and pigment, a filler and the like after polymerization, if necessary.

  The nitrile resin used as the constituent resin of the non-foamed layer (B) of the present invention contains 50% by weight or more of a component derived from an unsaturated nitrile monomer, and the heat insulation of the resulting thermoplastic resin foam Is preferable, and more preferably 55 to 95% by weight.

  The nitrile resin is preferably a (meth) acrylonitrile monomer in the presence of a (meth) acrylonitrile-styrene copolymer containing 50% by weight or more of a (meth) acrylonitrile monomer or a conjugated diene rubber-like polymer. ) A nitrile resin obtained by graft copolymerization of methyl acrylate and / or ethyl (meth) acrylate and, if necessary, other copolymerizable monomers, and contains 50 weight percent of components derived from (meth) acrylonitrile. It is a nitrile resin containing at least%.

  The nitrile resin used as the non-foamed layer (B) constituent resin of the present invention is a nitrile resin having different melt flow rate (MFR), molecular weight or molecular weight distribution, branched structure, other copolymerization component, molecular structure, etc. One or a combination of two or more can be used.

  The structure of the nitrile resin used as the non-foamed layer (B) constituent resin of the present invention is not particularly limited, and is any of a random copolymer, a block copolymer, or a graft copolymer. Also good.

  The styrene-unsaturated nitrile copolymer resin used as the non-foamed layer (B) resin of the present invention is a random, block or graft obtained by polymerizing a monomer containing styrene and an unsaturated nitrile monomer. It is a copolymer, and other monomers may be copolymerized.

  Examples of the unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. Of these, acrylonitrile and methacrylonitrile are preferred. Examples of other copolymerizable monomers include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Derivatives, polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, diene compounds such as budadiene or the like Derivatives, polymerizable unsaturated fatty acids such as itaconic acid, maleic acid, fumaric acid, crotonic acid, cinnamic acid, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropyl Unsaturated carboxylic acids such as maleic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, such as pyrmaleimide, N-phenylmaleimide, NP-bromophenylmaleimide, N-O-chlorophenylmaleimide, N-cyclohexylmaleimide Epoxy group-containing unsaturated compounds such as anhydrides, allyl glycidyl ether and glycidyl methacrylate, allylamine, aminoethyl methacrylate-aminopropyl methacrylate, amino group-containing unsaturated compounds such as aminostyrene, acrylamide, N- Examples thereof include acrylamide compounds such as methyl acrylamide, and hydroxyl group-containing unsaturated compounds such as 2-hydroxyethyl-acrylate, 3-hydroxypropyl methacrylate, and 4-hydroxy-2-butene. These may be used alone or in combination of two or more.

  Among the styrene-unsaturated nitrile copolymer resins used as the non-foamed layer (B) constituent resin of the present invention, extrusion foaming moldability, suppression of air intrusion into the foam over time, and increase in thermal conductivity over time From the viewpoint of suppression, a styrene-acrylonitrile copolymer and a styrene-methacrylonitrile copolymer are preferable, and a styrene-acrylonitrile copolymer is most preferable from the viewpoint of availability.

  The styrene-unsaturated nitrile copolymer resin in the present invention contains 1% by weight or more and less than 50% by weight of units derived from unsaturated nitrile monomers, and 50% by weight of units derived from styrene monomers. It is preferable to contain more than 99% by weight, 5% by weight to less than 40% by weight of units derived from unsaturated nitrile monomers, and 60% to less than 95% by weight units derived from styrene monomers. It is even more preferable that the unit derived from an unsaturated nitrile monomer is contained in an amount of 10% by weight to less than 35% by weight, and the unit derived from a styrene monomer is contained in an amount of 65% by weight or more and less than 90% by weight. When the styrene-unsaturated nitrile copolymer-based resin is outside these composition ranges, sufficient effects are obtained for extrusion foaming moldability, air entry into the foam over time, and improvement in thermal conductivity over time. It may not be possible.

  Further, the styrene-unsaturated nitrile copolymer resin used as the non-foaming constituent resin of the present invention is a styrene-unsaturated nitrile having a branched structure for the purpose of adjusting MFR, melt viscosity at the time of molding, melt tension, etc. It may be a copolymer resin.

  The styrene-unsaturated nitrile copolymer resin used as the non-foamed layer (B) constituent resin in the present invention may be used alone, and different styrenes such as copolymer components, molecular weight and molecular weight distribution, branched structure, and MFR. -Two or more types of unsaturated nitrile copolymer resins may be used in combination.

  In general, when a nitrile resin and a styrene-nitrile copolymer resin are compared, the nitrile resin is superior in terms of gas barrier properties (low air permeability). However, regarding the adhesiveness with the styrene resin that is the constituent resin of the foam layer (A), the styrene-unsaturated nitrile copolymer resin is superior, so at the interface of the foam layer (A) / non-foam layer (B). The styrene-unsaturated nitrile copolymer resin is superior in terms of the adhesiveness and the strength as an extruded foam. Further, the adhesiveness at the foam layer / non-foam layer interface can be further improved by adding a styrene resin to the non-foam layer (B) constituent resin.

  The non-foamed layer (B) constituting resin of the present invention may contain only a nitrile resin or only a styrene-unsaturated nitrile copolymer resin. Polymer resins and styrene resins are not completely compatible only by melt kneading when obtaining the non-foamed layer (B), so when both (or three) are used together, the gas barrier properties of nitrile resins and styrene -Unsaturated Nitrile Copolymer Resin / Styrene Resin Foam Layer (A) Since the adhesiveness of the constituent resin to the styrene resin can be compatible, it is more preferable.

  The fact that the two are not completely compatible is, for example, that when the glass transition temperature of the obtained extruded foam is measured using a differential scanning calorimeter, the glass transition temperature derived from the nitrile resin and the styrene- It is observed that glass transition temperatures derived from at least one resin selected from saturated nitrile copolymer resins and styrene resins appear separately.

  In this invention, when using a styrene resin as a foaming layer (A) constituent resin seed | species, as said non-foaming layer (B) constituent resin of this invention, you may contain a styrene resin from said reason.

  The styrene resin contained in the non-foamed layer (B) constituting resin of the present invention does not contain a unit derived from an unsaturated nitrile monomer. Other than that, there is no particular limitation. For example, it is obtained from a styrene homopolymer obtained only from a styrene monomer, a monomer copolymerizable with styrene other than a styrene monomer and an unsaturated nitrile monomer, or a derivative thereof. Specific examples include random, block or graft copolymers, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, and the like.

  Examples of the monomer copolymerizable with styrene include styrene such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Derivatives, polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate and ethyl methacrylate, diene compounds such as budadiene or the like Derivatives, polymerizable unsaturated fatty acids such as itaconic acid, maleic acid, fumaric acid, crotonic acid, cinnamic acid, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropyl Unsaturated carboxylic acids such as maleic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, such as pyrmaleimide, N-phenylmaleimide, NP-bromophenylmaleimide, N-O-chlorophenylmaleimide, N-cyclohexylmaleimide Epoxy group-containing unsaturated compounds such as anhydrides, allyl glycidyl ether and glycidyl methacrylate, allylamine, aminoethyl methacrylate-aminopropyl methacrylate, amino group-containing unsaturated compounds such as aminostyrene, acrylamide, N- Examples thereof include acrylamide compounds such as methyl acrylamide, and hydroxyl group-containing unsaturated compounds such as 2-hydroxyethyl-acrylate, 3-hydroxypropyl methacrylate, and 4-hydroxy-2-butene. These may be used alone or in combination of two or more.

  Of the styrene resins, styrene homopolymer, (meth) acrylic acid copolymerized polystyrene, maleic anhydride-modified polystyrene, impact-resistant polystyrene, and the like are preferable from the viewpoint of processability. Most preferred is a styrene homopolymer.

  Furthermore, the styrene resin contained in the non-foamed layer (B) constituent resin of the present invention is a styrene resin having a branched structure for the purpose of adjusting MFR, melt viscosity at the time of molding, melt tension, and the like. Also good.

  The styrene resin contained in the non-foamed layer (B) constituent resin of the present invention may be used alone, and two types of styrene resins having different copolymerization components, molecular weight, molecular weight distribution, branched structure, MFR, etc. You may mix and use above.

As the styrene resin contained in the non-foamed layer (B) constituting resin of the present invention, a mechanical strength when an MFR of 0.1 to 50 g / 10 min at 200 ° C. is used as an extruded foam. From the viewpoint of balance of toughness and the like. 0.3 to 30 g / 10 min is more preferable, and 0.5 to 20 g / 10 min is particularly preferable.
In the present invention, MFR is measured according to JIS K7210 (1999), Method A, test condition H.

  The mixing ratio of at least one resin selected from the group consisting of a nitrile resin, a styrene resin, and a styrene-unsaturated nitrile copolymer resin in the non-foamed layer (B) constituent resin of the present invention is a thermoplastic resin. Nitrile-based resin 0. 5 to 80% by weight, and at least one resin selected from the group consisting of a styrene resin and a styrene-unsaturated nitrile copolymer resin. It is preferably 5% by weight.

  Composition, MFR, molecular weight, branched structure, styrene resin and composition of at least one resin selected from the group consisting of styrene-unsaturated nitrile copolymer resins, MFR, molecular weight, branched structure However, from the viewpoint of balance such as gas barrier property and molding processability, at least one selected from the group consisting of 5-70% by weight of a nitrile resin and a styrene resin and a styrene-unsaturated nitrile copolymer resin. More preferably, the resin is 30 to 95% by weight, and the nitrile resin is 10 to 60% by weight, and at least one resin selected from the group consisting of a styrene resin and a styrene-unsaturated nitrile copolymer resin is 40 to 90% by weight. Particularly preferred.

More specifically, although depending on the composition, MFR, molecular weight, and branched structure of each resin component to be used, from the viewpoint of gas barrier properties, molding processability, and adhesiveness with the foamed layer (A), the nitrile resin 0. 5 to 80 wt% and styrene-unsaturated nitrile copolymer resin 20 to 99.5 wt%, or nitrile resin 0.5 to 80 wt, styrene resin 19.5 to 99 wt% and styrene -It is preferable that it is 0.5-80 weight% of unsaturated nitrile copolymer type resin.
Also, 5-70% by weight of nitrile resin and 30-95% by weight of styrene-unsaturated nitrile copolymer resin, or 5-70% by weight of nitrile resin, 25-90% by weight of styrene resin, and styrene-unsaturated. More preferably, it is 5 to 70% by weight of nitrile copolymer resin, 10 to 60% by weight of nitrile resin and 40 to 90% by weight of styrene-unsaturated nitrile copolymer resin, or 10 to 60% by weight of nitrile resin. %, Styrene-based resin 30 to 80% by weight, and styrene-unsaturated nitrile copolymer resin 10 to 60% by weight are particularly preferable. When the mixing ratio of at least one resin selected from a styrene resin and a styrene-unsaturated nitrile copolymer resin is in the range of 0.5 to 99% by weight, an extruded foam excellent in molding processability is obtained. The mixing ratio of nitrile resin is 0. In the range of 5 to 80% by weight, a good extruded foam having a heat insulating improvement effect and molding processability in the present invention can be obtained.

  The foamed layer (A) of the extruded foam in the present invention is obtained by press-fitting a foaming agent into a melted foamed layer-constituting resin under high pressure, melt-kneading, and then releasing to the atmosphere. , Not particularly limited, for example, hydrocarbons such as methane, ethane, propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, cyclopentane, and the like; dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl Ethers such as ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methylfuran, tetrahydrofuran, tetrahydropyran; acetone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, methyl i-butyl ketone, Methyl n-amino Ketones such as ketone, methyl n-hexyl ketone, ethyl n-propyl ketone and ethyl n-butyl ketone; alcohols such as methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol and t-butyl alcohol Esters such as methyl formate, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate; methyl chloride, ethyl chloride, etc. Alkyl halides; inorganic foaming agents such as nitrogen, air, water and carbon dioxide; and chemical foaming agents such as azo compounds and tetrazole. Also, fluorinated hydrocarbons having zero ozone depletion coefficient and low global warming potential can be used. These foaming agents can be used alone or in combination of two or more.

  Among the foaming agents, hydrocarbons such as propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, and cyclopentane are preferable because they can achieve both extrusion foam moldability and high heat insulation. Since the thermal conductivity is low as the characteristics of the gas itself and the permeability to the thermoplastic resin constituting the extruded foam is low, a highly heat-insulated extruded foam is obtained and its performance is maintained for a long time. -Butane, i-butane and cyclopentane are particularly preferred.

  Moreover, ethers such as dimethyl ether, diethyl ether and methyl ethyl ether; methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t- Alcohols such as butyl alcohol; alkyl halides such as methyl chloride and ethyl chloride are preferred. Further, inorganic foaming agents such as nitrogen, air, water and carbon dioxide are preferred from the viewpoint of nonflammability and excellent environmental compatibility.

  From the standpoint of obtaining a lightweight and highly heat-insulating extruded foam molding, one or more hydrocarbons selected from n-butane, i-butane, and cyclopentane, and carbon dioxide, dimethyl ether, diethyl ether, and methyl ethyl ether A group consisting of ethers such as methanol, ethanol, propyl alcohol, i-propyl alcohol, alcohols such as butyl alcohol, i-butyl alcohol, and t-butyl alcohol, and halogenated alkyls such as water, methyl chloride, and ethyl chloride It is preferable to use a combination of one or more compounds selected from.

  The amount of the foaming agent that is press-fitted into the melted foam layer-constituting resin is appropriately selected according to the setting value of the foaming ratio, etc., but from the point of obtaining a lightweight and highly heat-insulating extruded foam, The total amount of the foaming agent is preferably 1 to 20 parts by weight and more preferably 3 to 8 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

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

  In terms of obtaining a highly heat-insulating extruded foam, 0.5 to 5 parts by weight of hydrocarbons such as n-butane, i-butane, and cyclopentane are obtained with respect to 100 parts by weight of the obtained extruded foam. It is preferable to contain.

  The average cell diameter in the foamed layer made of the thermoplastic resin constituting the extruded foam of the present invention is preferably 0.03 to 1 mm, more preferably 0.03 to 0.4 mm, and particularly preferably 0.03 to 0.3 mm. 3 mm.

  Moreover, when using together at least 1 sort (s) from the group which consists of water, alcohol aqueous solution, and aqueous solution of inorganic salt as a foaming agent, it is less than 1.2 times of average bubble diameter D2 in a foam, and is 0.25 mm or less. A foam layer having a characteristic bubble structure in which bubbles having a bubble diameter (small bubbles) and bubbles having a bubble diameter of 1.2 times or more of the average bubble diameter D2 (large bubbles) are mixed in a sea-island shape is obtained, Since this cellular structure contributes to the improvement of the heat insulation performance of the obtained extruded foam, it is preferable to use water and / or an aqueous solution in combination as a foaming agent.

  Further, in the foam layer having a specific cell structure in which small bubbles and large cells having a bubble diameter of 0.25 mm or less are mixed, the ratio of the area of the small bubbles in the cross section of the foam layer located in the central portion in the thickness direction ( Occupied area ratio per unit cross-sectional area) (hereinafter referred to as “small bubble area ratio”) is preferably 5 to 98%, more preferably 10 to 90%, particularly preferably 20 to 80%, and most preferably 25 to 25%. 70%. When the small bubble area ratio is in the range of 5 to 98%, an extruded foam having a low density and excellent heat insulating performance can be obtained.

  When water and / or an aqueous solution are used as the foaming agent, the content of water with respect to the total amount of the foaming agent is preferably 1 to 80% by weight, more preferably, from the viewpoint of ease of formation of small bubbles and large bubbles and processability. It is 2 to 70% by weight, particularly preferably 3 to 60% by weight.

  When water and / or an aqueous solution are used as the foaming agent, water-absorbing or water-swelling layered silicates such as smectite and swellable fluorinated mica or their organically treated products, water-absorbing polymers, Nippon Aerosil Co., Ltd. By adding one or more of anhydrous silica having a silanol group such as AEROSIL manufactured (in the present specification, these substances are collectively referred to as “water-absorbing substance”), The effect | action which a small bubble and a large bubble generate | occur | produce can be improved further, and the moldability of the obtained foam, productivity, and heat insulation performance can further be improved.

  Here, it is considered that the water-absorbing substance used can absorb water that is not compatible with the thermoplastic resin to form a gel, and can be uniformly dispersed in the thermoplastic resin in a gel state. Used from.

  The amount of the water-absorbing substance used when producing the foamed layer (A) constituting the extruded foam of the present invention is appropriately adjusted depending on the amount of water added. Generally, a thermoplastic resin is used. The amount is preferably 0.2 to 10 parts by weight, more preferably 0.3 to 8 parts by weight, and particularly preferably 0.5 to 7 parts by weight with respect to 100 parts by weight. When the added amount of the water-absorbing substance is 0.2 to 10 parts by weight, water is well dispersed in the extruder, and a foamed layer having a good cell structure free from bubble unevenness and voids is obtained, and there is no variation. An extruded foam having good heat insulation performance can be obtained.

  The layered silicate used in producing the foamed layer (A) constituting the extruded foam of the present invention is a tetrahedral sheet mainly composed of silicon oxide and an octahedron mainly composed of a metal hydroxide. A primary particle comprising a sheet, wherein the tetrahedral sheet and the octahedral sheet form a unit layer, a unit layer single structure, or a structure in which a plurality of unit layers are laminated via a cation between layers, and It exists as an aggregate (secondary particle) of primary particles. Specific examples of the layered silicate include, for example, smectite clay and swellable mica.

The smectite clay is represented by the following general formula (I)
X _0.2-0.6 Y _2-3 Z ₄ O ₁₀ (OH) ₂ .nH ₂ O... General formula (I)
(However, X is at least one selected from the group consisting of K, Na, 1 / 2Ca, and 1 / 2Mg, and Y is a group consisting of Mg, Fe, Mn, Ni, Zn, Li, Al, and Cr. And Z is at least one selected from the group consisting of Si and Al, where H ₂ O represents a water molecule bonded to an interlayer ion, and n is an interlayer ion. And varies significantly depending on the relative humidity).

  Specific examples of the smectite group clay include, for example, montmorillonite, beidellite, nontronite, saponite, iron saponite, hectorite, soconite, stevensite, bentonite, and the like, or a substitution product, a derivative thereof, or a mixture thereof. .

The swellable mica is represented by the following general formula (II)
X _0.5-1.0 Y _2-3 (Z ₄ O ₁₀ ) (F, OH) ₂ ... General formula (II)
(However, X is at least one selected from the group consisting of Li, Na, K, Rb, Ca, Ba, and Sr, and Y is selected from the group consisting of Mg, Fe, Ni, Mn, Al, and Li) Z is one or more selected from the group consisting of Si, Ge, Al, Fe, and B), and is natural or synthesized.

  These are water, a polar organic compound that is compatible with water in an arbitrary ratio, and a substance that swells in a mixed solvent of water and the polar organic compound. For example, lithium teniolite, sodium Type teniolite, lithium type tetrasilicon mica, sodium type tetrasilicon mica and the like, or a substituted product, a derivative thereof, or a mixture thereof.

Some of the swellable mica have a structure similar to vermiculites, and such vermiculites and the like can also be used. The vermiculite-equivalent products include three octahedron type and two octahedron type, and the following general formula (III)
_{(Mg, Fe, Al) 2~3} (Si 4-x Al x) O 10 (OH) 2 · (M +, M 2 + 1/2) x · nH 2 O ······ formula (III)
(Wherein M is an exchangeable cation of an alkali or alkaline earth metal such as Na and Mg, x = 0.6 to 0.9, and n = 3.5 to 5). .

  Swellable layered silicates may be used alone or in combination of two or more. Of these, smectite clay and swellable mica are preferred from the viewpoint of dispersibility in the resulting foam, and have sodium ions between layers such as montmorillonite, bentonite, hectorite, synthetic smectite, and swellable fluorine mica. Swellable mica is more preferred.

  Typical examples of bentonite include natural bentonite and purified bentonite. Also, organic bentonite can be used. The smectite in the present invention includes montmorillonite-modified products such as anionic polymer-modified montmorillonite, silane-treated montmorillonite, and highly polar organic solvent composite montmorillonite.

  The content of smectite such as bentonite is appropriately adjusted depending on the amount of water added, but is preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Part by weight is more preferred, 0.5 to 7 parts by weight is particularly preferred, and 1 to 5 parts by weight is most preferred.

  If the smectite content is less than 0.2 parts by weight, the amount of water adsorbed by the smectite is insufficient with respect to the amount of water injected, and pores due to poor dispersion of water tend to occur in the extruder, resulting in a defective molded body. .

  On the other hand, when the content of smectite exceeds 10 parts by weight, the amount of inorganic powder present in the thermoplastic resin becomes excessive, so that uniform dispersion in the thermoplastic resin becomes difficult, and bubble unevenness occurs. Furthermore, it tends to be difficult to maintain closed cells. Therefore, it becomes easy to produce deterioration and variation of the heat insulation performance of a foam.

  The mixing ratio of water / smectite (bentonite) is preferably 0.02 to 20, more preferably 0.1 to 10, particularly preferably 0.15 to 5, and most preferably in the range of 0.25 to 2, in terms of weight ratio. preferable.

The density of the foamed layer constituting the extruded foam of the present invention is preferably 10 to 60 kg / m ³ , more preferably 15 to 50 kg / m ³ in order to give light weight and excellent heat insulation.

  In the production of the foamed layer (A) constituting the extruded foam of the present invention, a halogen-based flame retardant, a halogen-phosphorus flame retardant, a phosphorus flame retardant, a nitrogen flame retardant, a nitrogen-phosphorus system, if necessary. Flame retardants, flame retardants such as nitrogen-halogen flame retardants; flame retardant aids such as phosphorus compounds, nitrogen compounds, boron compounds, metal oxides, iron-containing compounds, radical initiators; silica, talc, silicic acid Inorganic compounds such as calcium, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate; sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, epoxy Processing aids such as compounds; phenolic antioxidants; phosphorus stabilizers, nitrogen stabilizers, sulfur stabilizers, benzos Riazor acids, light stabilizers such as hindered amines; antistatic agents; be added additives such as colorants such as pigments preferred. Furthermore, you may add the heat ray radiation suppression material mentioned later.

  The thickness of the foamed layer (A) constituting the extruded foam of the present invention is the thickness of the extruded foam and the number of foamed layers in the extruded foam (foamed layer (A) / non-foamed layer (B) / foamed). The number is appropriately selected according to the number of units comprising the layer (A).

  The structure of the non-foamed layer (B) constituting the extruded foam of the present invention is not particularly limited, and any structure of a single layer or multiple layers can be adopted. The thickness of the non-foamed layer (B) is appropriately determined according to the thickness of the extruded foam and the number of foamed layers (A) in the extruded foam (number of units composed of foamed layer / non-foamed layer / foamed layer). Selected.

  The thickness of the non-foamed layer (B) is not limited as long as it has a thickness that is 1.1 times or more larger than the thickened portion of the bubble wall or bubble wall bonding portion of the bubbles constituting the foam layer, preferably 5 ˜500 μm, more preferably 5˜300 μm, particularly preferably 5˜200 μm, and most preferably 5˜100 μm. When the thickness of the non-foamed layer is in the range of 5 to 500 μm, an extruded foam having lightness and heat insulation can be obtained.

  In addition, the foamed layer and the non-foamed layer in the obtained extruded foam are flat in the flow direction and the width direction, and the respective layers spread in a substantially parallel state. Preferred for obtaining a foam. For this reason, when the coextrusion method to be described later is adopted as a method for producing an extruded foam, the non-foamed layer constituent resin is composed of a foamed layer constituent resin, a foaming agent, and an optional additive in a molten state at a molding temperature. It is preferable that the melt viscosity is as close as possible to the molten resin composition. As this means, for example, a method of adjusting the molecular weight of the non-foamed layer constituent resin, a method of adding an additive having plasticizing ability to the non-foamed layer constituent resin, and a melt viscosity for the non-foamed layer constituent resin. And a method of adding an additive to be improved.

  Examples of the additive that is added to adjust the melt viscosity of the non-foamed layer constituent resin include a plasticizer, a compound having a melt viscosity lower than that of the non-foamed layer constituent resin, and a compatible compound.

The plasticizer is not particularly limited, and any compound generally used as a plasticizer can be used. For example, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) , Di-2-ethylhexyl phthalate (DOP), dinormaloctyl phthalate (DNOP), diisononyl phthalate (DINP), dinonyl phthalate (DNP), diisodecyl phthalate (DIDP), butylbenzyl phthalate (BBP), Phthalic acid esters such as phthalic acid mixed ester (C ₆ -C ₁₁ ); dioctyl adipate (DOA), diisononyl adipate (DINA), dialkyl adipate (C6, 8, 10) (610A), dialkyl adipate _{(C 7, C 9) (} 79A) dioctyl azelate (DOZ) Se Dibutyl silicate (DBS), dioctyl sebacate (DOS), tricresyl phosphate (TCP), tributyl acetylcitrate (ATBC), epoxidized soybean oil (ESBO), trioctyl trimellitic acid (TOTM), chlorinated paraffin, etc. Non-phthalic acid esters and the like.

  The amount of the plasticizer added to the non-foamed layer (B) constituent resin is appropriately selected depending on the target melt viscosity, but is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the non-foamed layer constituent resin. Part by weight is more preferable, 3 to 12 parts by weight is particularly preferable, and 4 to 10 parts by weight is preferable. When the addition amount of the plasticizer is in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the non-foamed layer constituting resin, a non-foamed layer with no discharge fluctuation during extrusion and no surface bleed-out after extrusion is obtained. .

Examples of the compound having a melt viscosity lower than that of the non-foamed layer (B) resin and having compatibility are phosphoric esters such as triphenyl phosphate, flame retardant, flame retardant aid, stabilizer, Among other types of non-foamed layer-constituting resins, there are compounds that can achieve the same effect.
In the non-foamed layer (B) constituting resin constituting the extruded foam of the present invention, if necessary, a plasticizer, a flame retardant, a flame retardant aid, silica, talc, calcium silicate, wollastonite, kaolin, Inorganic compounds such as clay, mica, zinc oxide, titanium oxide, calcium carbonate, processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, phenolic antioxidant Additives such as light stabilizers such as additives, phosphorus stabilizers, nitrogen stabilizers, sulfur stabilizers, benzotriazoles, hindered amines, antistatic agents, colorants such as pigments, and heat radiation inhibitors can do.

  The heat ray radiation inhibitor added to the non-foamed layer (B) constituting the extruded foam of the present invention reflects light in the near infrared or infrared region (for example, a wavelength region of about 800 to 3000 nm). A substance having the property of scattering / absorbing means a substance having a black body emissivity smaller than that of the resin constituting the foamed layer and the non-foamed layer. As a heat ray radiation inhibitor, the heat ray reflective agent and heat ray absorber which are described below are mentioned.

  The heat ray reflective agent is not particularly limited as long as it is a substance that reflects and scatters light in the near infrared or infrared region (for example, a wavelength range of about 800 to 3000 nm). Specifically, aluminum, aluminum oxide Aluminum compounds such as zinc aluminate; magnesium compounds such as hydrotalcite; silver compounds such as silver: titanium compounds such as titanium, titanium oxide, strontium titanate; stainless steel, nickel, tin Silver, copper, bronze, shirasu balloon, ceramic balloon, microballoon, pearl mica and the like. These may be used alone or in combination of two or more.

  As a heat ray reflective agent, from the viewpoints of great thermal conductivity reduction effect, cost advantage, environmental compatibility, good handling properties including safety, etc., aluminum compounds, magnesium compounds, Silver-based compounds or titanium-based compounds are preferable, and among these, aluminum paste and titanium oxide are more preferable because of the excellent balance between the thermal conductivity reduction effect and cost.

  The amount of heat ray reflective agent added to the non-foamed constituent resin is appropriately set according to the type of heat ray reflective agent and the thickness of the non-foamed layer, but as an indicator, a predetermined amount of heat ray reflective agent is added to the non-foamed constituent resin. After melt-kneading, a film having the same thickness as the non-foamed layer was prepared, and the absorbance obtained at 800 to 3000 nm in the spectrum obtained by infrared spectrophotometer (IR) measurement of the film hardly changed even when the addition amount was increased. It is preferable to set the minimum amount that reaches such a region as the amount of addition because the balance between the effect of reducing the thermal conductivity of the extruded foam and the cost is excellent.

  The said heat ray absorber means the substance which has the characteristic which absorbs the light of near infrared or infrared region (for example, wavelength range of about 800-3000 nm).

  The heat ray absorbent is not particularly limited as long as it is a substance that absorbs light in the near infrared or infrared region (for example, a wavelength range of about 800 to 3000 nm), and specifically, carbon black, carbon powder. ; Metal sulfates such as barium sulfate, strontium sulfate, calcium sulfate, mercalite, halothrite, alumite, iron alumite; antimony compounds such as antimony trioxide, antimony oxide, and anhydrous zinc antimonate; tin oxide, indium oxide Metal oxides such as zinc oxide, indonium tin oxide, etc .; ammonium, urea, imonium, aminium, cyanine, polymethine, anthraquinone, dithiol, copper ion, phenylenediamine, phthalocyanine, benzo Triazole, benzophenone, oxalic anilide, shear Acrylate, organic dyes and pigments benzotriazole and the like; and the like.

  As a heat ray absorbent, carbon graphite, carbon black, metal sulfate, etc. from the viewpoints of great thermal conductivity reduction effect, cost advantage, good handling properties including environmental compatibility and safety. Salts or antimony compounds are preferred, and among these, carbon graphite, carbon black, antimony oxide or barium sulfate is more preferred because of its excellent thermal conductivity reduction effect and cost balance.

  The amount of heat-ray absorbent added to the non-foamed constituent resin is appropriately set according to the type of heat-ray absorbent and the thickness of the non-foamed layer. As an indicator, a predetermined amount of heat-ray absorbent is added to the non-foamed constituent resin. After melt-kneading, a film having the same thickness as the non-foamed layer was prepared, and the absorbance obtained at 800 to 3000 nm in the spectrum obtained by infrared spectrophotometer (IR) measurement of the film hardly changed even when the addition amount was increased. It is preferable to set the minimum amount that reaches such a region as the amount of addition because the balance between the effect of reducing the thermal conductivity of the extruded foam and the cost is excellent.

  The method for producing the extruded foam of the present invention, particularly the method for laminating the foamed layer (A) and the non-foamed layer (B) is not particularly limited. For example, it adheres to the outermost surface (the surface to be adhered to the foamed layer). A non-foamed layer (B) having adhesiveness / adhesiveness (or imparted tackiness / adhesiveness) to a film or a sheet in advance, and sandwiching this with a pre-formed foamed layer (A) and then pressure bonding A method in which the non-foamed layer (B) constituent resin is melt-kneaded using an extruder, and the melted non-foamed layer (B) constituent resin is sandwiched between the pre-formed foamed layer (A) and pressure-bonded; A method in which the non-foamed layer (B) and the foamed layer (A) are used, and the non-foamed layer (B) is sandwiched between the foamed layers (A), followed by thermocompression bonding; the non-foamed layer (B) and the foamed layer (A ) Are melt-kneaded using different extruders, and the molten resins are joined together in multiple layers and laminated. And the like; a method of foam molding after.

  In addition, when a styrene resin is used as the constituent resin of the foam layer (A), the resin having adhesiveness and adhesiveness with the resin is polyolefin resin, vinyl chloride resin, vinylidene chloride resin, vinyl alcohol resin. Resin, ethylene-vinyl alcohol copolymer resin, acrylic resin, styrene-butadiene copolymer resin, natural rubber resin, chloroprene resin, and rosins, rosin derivatives, petroleum resins, terpene resins And a resin composition formed by blending a tackifier resin such as a phenol resin, a rosin phenol resin, or a ketone resin.

  Among these production methods, for the extruded foam of the present invention, the constituent resins of the foam layer (A) and the non-foam layer (B) are melt-kneaded using different extruders, etc. Use molten resin that does not contain foaming agent and molten resin, and use a multi-layer laminating apparatus to merge and melt the molten resin in multiple layers in a high-pressure region, then extrude and foam through a die to a low-pressure region. It is preferable to produce by forming a layer and then molding. By obtaining an extruded foam by the coextrusion method, the non-foamed layer (B) can suppress the intrusion of air into the foamed layer (A) cell that occurs immediately after production. By adopting a structure in which both sides of A) are covered with the non-foamed layer (B), the infiltration of air from the outside air into the foam layer cell is suppressed, and the heat insulation performance of the resulting foam can be further improved. it can.

  In the present invention, a method for laminating each molten resin in a multilayer shape by a multilayer laminating apparatus is not particularly limited, and examples thereof include a feed block method and a multi-manifold method generally used for coextruded films; A method of repeating division and lamination after creating a laminated flow composed of a plurality of layers as described in JP-A-54-23025, JP-A-4-278323, and the like; JP-T-2005-523831, JP-A-2004-249520 And a method of sequentially laminating a plurality of divided flows described in Japanese Patent Gazette.

  The temperature of the multilayer laminating apparatus when producing the extruded foam is preferably equal to or less than ± 10 ° C. even if it is equal to or different from the resin temperature of the foaming agent-containing molten resin supplied to the multilayer laminating apparatus. When the temperature difference is ± 10 ° C. or less, molding with a die can be performed at an appropriate foaming temperature, and an extruded foam having a foam layer with a high magnification and a low closed cell ratio can be obtained.

  The pressure in the multilayer laminating apparatus when producing the extruded foam is set to a pressure at which the foaming agent-containing molten resin supplied to the multilayer laminating apparatus does not cause foaming in the multilayer laminating apparatus. However, the pressure that does not cause foaming in the multi-layer laminating apparatus cannot be generally set because it depends on the type of foaming agent, the amount of foaming agent, and the temperature of the foaming agent-containing molten resin.

  In the present invention, the foam molding method is not particularly limited, but for example, using a molding die and a molding roll in which a foam obtained by releasing pressure from a slit die is placed in close contact with or in contact with the slit die, A general method for molding a plate-like foam having a large size can be used.

As described above, the skin layer has a lower temperature than the part not in contact with the surface of the extruded foam surface in contact with the extrusion mold. It is formed by being 5 kg / m ³ or more heavier than the density of the whole foam.

Regarding the melt kneading of the constituent resin of the foam layer,
(I) The thermoplastic resin is mixed with the additive as necessary, and then melted by heating.
(Ii) One or more selected from the above-mentioned additives as necessary are mixed into the thermoplastic resin, and then heated and melted, and the remaining additive is added to the thermoplastic resin as it is, or liquefied or melted as necessary. Then heat and mix,
(Iii) A thermoplastic resin is mixed with one or more additives selected from the above-mentioned additives as necessary, and then a heat-melted composition is prepared, and then the composition and the remaining additives , If necessary, mix the thermoplastic resin again, supply to the extruder and melt by heating,
Etc., thermoplastic resin, if necessary, supply the additive to a hot melt extruder,
Thereafter, in any stage, a foaming agent is added to the thermoplastic resin under high-pressure conditions to obtain a molten resin containing the foaming agent (hereinafter sometimes referred to as “flowing gel”). Thereafter, the fluid gel is cooled to a temperature suitable for extrusion foaming and then supplied to the multilayer laminating apparatus.

There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the thermoplastic resin and additives such as a foaming agent.
Although the heating temperature should just be more than the temperature which the thermoplastic resin to be used melt | dissolves, the temperature which suppresses the molecular degradation of resin by the influence of a flame retardant etc. as much as possible, for example, about 150-280 degreeC is preferable.
The melt-kneading time varies depending on the extrusion amount per unit time, the melt-kneading means, and the like, and thus cannot be determined unconditionally. However, the time required for uniformly dispersing and mixing the thermoplastic resin and the foaming agent is appropriately selected.
Examples of the melt-kneading means include a screw type extruder, but there is no particular limitation as long as it is used for normal extrusion foaming. However, in order to suppress the molecular deterioration of the resin as much as possible, it is preferable to use a low shear type screw shape for the screw shape.

Further, regarding the melt kneading of the constituent resin of the non-foamed layer, for example,
(I) The thermoplastic resin is mixed with the additive as necessary, and then melted by heating.
(Ii) One or more selected from the above-mentioned additives as necessary are mixed into the thermoplastic resin, and then heated and melted, and the remaining additive is added to the thermoplastic resin as it is, or liquefied or melted as necessary. Then heat and mix,
(Iii) A thermoplastic resin is mixed with one or more additives selected from the above-mentioned additives as necessary, and then a heat-melted composition is prepared, and then the composition and the remaining additives , If necessary, mix the thermoplastic resin again, supply to the extruder and melt by heating,
For example, a thermoplastic resin, and if necessary, the additive is supplied to an extruder and heated and melt-kneaded. Thereafter, the melt-kneaded product is supplied to a multilayer laminating apparatus.

There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when the thermoplastic resin and additive are heat melt kneaded.
The heating temperature may be equal to or higher than the temperature at which the thermoplastic resin to be used melts, but the temperature difference is within ± 10 ° C even if it is equal to or different from the set temperature of the multilayer laminating apparatus to which the molten resin is supplied. Is preferred. When the temperature difference is ± 10 ° C. or less, it is possible to obtain a good extruded foam that does not have bubble breakage at the interface portion between the foamed layer and the non-foamed layer and does not have poor adhesion.
The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means, etc., and thus cannot be generally determined, but the time required for uniformly dispersing and mixing the thermoplastic resin and the additive is appropriately selected. .
Examples of the melt-kneading means include a screw type extruder, but there is no particular limitation as long as it is used for ordinary resin extrusion. However, in order to suppress the molecular deterioration of the resin as much as possible, it is preferable to use a low shear type screw shape for the screw shape.

  As the structure of the extruded foam of the present invention, for example, a foamed layer (A) is formed in the thickness direction of the extruded foam as a foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer. And a structure having at least two non-foamed layers (B). This is because, in the structure in which the foamed layer (A) is laminated on both sides of the non-foamed layer (B), the effect of reducing the thermal conductivity by the heat ray radiation inhibitor contained in the non-foamed layer (B) is effective. by. In the structure in which the foamed layer (A) is laminated only on one side of the non-foamed layer (B) such as non-foamed layer / foamed layer / non-foamed layer, the heat ray radiation inhibitor contained in the non-foamed layer (B) There is a tendency that the effect of reducing thermal conductivity due to is not sufficiently exhibited.

  Generally, the time-dependent change in heat insulation of an extruded foam without a skin layer is due to the removal of the skin layer that has a high density and suppresses the intrusion of air into the foam. Compared to tend to be worse. Therefore, when the non-foamed layer (B) is less than two layers and the skin layer is removed, the intrusion of air from the outside air into the foamed layer cell is not sufficiently suppressed, and the heat insulating property of the extruded foam is deteriorated over time. There is a tendency not to improve change.

  As a method for controlling the average cell diameter of the foam layer constituting the extruded foam of the present invention, silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate, carbonate Examples thereof include a nucleating agent typified by an inorganic compound such as sodium hydride and the layered silicate added to the foamed layer-constituting resin and adjusting the amount of these additives. The average cell diameter is also adjusted by the type, composition and addition amount of the foaming agent. Also, depending on the screw shape of the extruder that is the melt kneading means, the heating temperature, the pressure, the amount of the melt-kneaded foam layer constituting resin composition discharged from the die lip, the die shape, the resin temperature at the time of discharge, etc. The average bubble diameter is adjusted.

  The thickness of the extruded foam of the present invention is not particularly limited, and is appropriately selected depending on the application. For example, in the case of a heat insulating material used for a building material or the like, in order to impart a preferable heat insulating property, bending strength and compressive strength, the thickness of a normal plate-like material is less than a thin material such as a sheet. Some are preferred, usually 10 to 150 mm, preferably 20 to 100 mm.

The thermal conductivity at 20 ° C. of the extruded foam of the present invention is preferably 0.0280 W / m · K or less, more preferably 0.0260 W / m · K or less, after 1 day of production. It is preferable that it is 0.0300 W / m * K or less after 30 days.
An extruded foam having a thermal conductivity of 0.0280 W / m · K or less after 1 day of manufacture and 0.0300 W / m · K or less after 30 days of manufacture is suitably used as a building material application, and is a comfortable living space. Contribute to the provision of

  The difference in thermal conductivity between 1 day and 30 days after the production of the extruded foam in the present invention is preferably 0.0030 W / mK or less, and more preferably 0.0020 W / mK or less. Extruded foam having a difference in thermal conductivity of 0.0030 W / mK or less after 1 day and 30 days from the production of the extruded foam is said to be a comfortable residence for a long time when used as a building member. Can contribute to the provision of space.

  Generally, the thermal conductivity of air is higher than that of the foaming agent present in the foam of the extruded foam after the production of the extruded foam, so that the air partial pressure in the foam of the extruded foam increases. And as the partial pressure of the foaming agent decreases, the thermal conductivity of the extruded foam deteriorates.

  The air partial pressure in the bubbles of the extruded foam of the present invention is preferably less than 90 kPa, more preferably less than 80 kPa, 30 days after the production of the extruded foam. When the air partial pressure is 90 kPa or more 30 days after the production of the extruded foam, the difference in thermal conductivity between 1 day and 30 days after the production of the extruded foam tends to be larger than 0.0030 W / mK.

  The extruded foam of the present invention has various uses, for example, building materials such as floor materials, wall materials, and roof materials, heat insulation materials for cold cars, vehicle bumpers, automobiles, etc. from the viewpoint of excellent light weight and heat insulation properties. It can be suitably used for automobile members such as ceiling materials and civil engineering members such as antifreezing agents for the ground.

  Next, the present invention will be described in detail based on examples, but the present invention is not limited to such examples. Unless otherwise specified, “%” represents wt%.

  Evaluation methods for Examples and Comparative Examples are as follows.

(1) Air permeability measurement (unit: cc · cm / cm ² · s · cmHg)
The resin pellet was melt-pressed to produce a resin film having a thickness of 100 to 200 μm. The air permeability of the produced resin film was measured by a differential pressure method in accordance with JIS K7126 (2006) using a differential pressure type gas permeation device (GTR-Tech, GTR-31A) and a detector (Yanaco Measurements, G2700T). Temperature 23 ° C. ± 2 ° C., relative humidity 0% R.B. H. The measurement was performed under the following conditions.

(2) Density of extruded foam (unit: kg / m ³ )
For three extruded foams sampled at different times, the foam density was measured according to the method described in JIS K7222-1999 “Measurement of Foamed Plastic and Rubber—Apparent Density”, and the average value was calculated.

(3) Thermal conductivity (unit: W / m · K)
1 day or 30 days after production, under conditions of standard temperature state class 3 (23 ° C. ± 5 ° C.) and standard humidity state class 3 (50 ^{+ 20, −10} % RH) specified in JIS K 7100 The thermal conductivity of the extruded foam after being left standing was measured using a thermal conductivity measuring device (Eihiro Seiki, HC-074-300).
Evaluation was made as follows from the difference in thermal conductivity after 1 day and 30 days after production.
○: [Thermal conductivity after 30 days of production] − [Thermal conductivity after 1 day of production] ≦ 0.0030 W / m · K
×: [Thermal conductivity after 30 days of production] − [Thermal conductivity after 1 day of production]> 0.0030 W / m · K

(4) Partial pressure of air in extruded foam bubbles 1 day or 30 days after production, standard temperature state class 3 (23 ° C. ± 5 ° C.) defined in JIS K 7100, and standard humidity state class 3 (50 ^{+ 20 -10} % RH) After leaving the extruded foam after being left out under the condition of ^-10 % RH) ^{, a 10} mm portion was removed from the cut surface, and then the width direction was 25 mm, the length direction was 25 mm, and the thickness direction was It cuts out with the thickness as it is a foam, and the amount of air in an extrusion foam is analyzed and measured using a gas chromatograph (GC-14A made by Shimadzu Corporation), and an average value is calculated. The partial pressure of air was determined.

(5) Thickness accuracy The thickness direction dimension of the obtained extruded foam cross section was measured using a caliper (Mittoyo Corp., M-type standard caliper).
Measured at three points of both ends and the center in the width direction. From the average value Y (mm) of the thickness direction dimensions of the both ends in the width direction and the thickness direction dimension X (mm) of the center portion in the width direction, The thickness accuracy was calculated using the formula and evaluated according to the following criteria.
Thickness accuracy (%) = ((X−Y) / X) × 100
○: The thickness accuracy is within ± 2%.
X: Thickness accuracy exceeds ± 2%.

(Example 1)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 46.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.2 MPa, and the press injection pressure of the foaming agent was set to 13.1 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (Mitsui Chemicals, trade name: Valex 2090MN, acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 30 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ cc · cm / cm ² · S · cmHg) and 10 parts by weight of polystyrene (manufactured by PS Japan, trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / A mixture comprising 60 parts by weight of cm ² · S · cm Hg) was dry blended to obtain a blend resin. To 100 parts by weight of the blend resin, 6.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.1 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction at a pressure of 5.7 MPa in the two-type seven-layer multi-layered feed block in which one non-foamed layer flow path adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both the upper and lower surfaces using a vertical slicer [manufactured by Sakura Machinery Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 mm × thickness 0.5 mm × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Example 2)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.4 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.6 MPa, and the press injection pressure of the foaming agent was set to 13.2 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 60 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ cc · cm / cm ² · S · cmHg) and 10 parts by weight of polystyrene (manufactured by PS Japan, trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / A mixture comprising 30 parts by weight of cm ² · S · cm Hg) was dry blended to obtain a blend resin. To 100 parts by weight of the blend resin, 6.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 9.9 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 5.9 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Example 3)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 46.2 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.2 Mpa, on the other hand, the press injection pressure of the foaming agent was set to 12.9 Mpa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹ cc · cm / cm ² · S · cmHg) To 100 parts by weight, 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.2 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 6.1 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow path adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

Example 4
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrene-based resin composition was supplied at 45.2 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.3 MPa, and the press injection pressure of the foaming agent was set to 13.0 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / To 100 parts by weight of cm ² · S · cmHg), 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 9.8 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 5.9 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Example 5)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.6 Mpa, on the other hand, the press injection pressure of the foaming agent was set to 12.8 Mpa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 30 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ A mixture consisting of 70 parts by weight of cc · cm / cm ² · S · cmHg was dry blended to obtain a blended resin. To 100 parts by weight of the blend resin, 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch in advance.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.3 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 6.4 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 1)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. At this time, the resin pressure at the tip of the first extruder was 11.0 MPa, while the press-fitting pressure of the foaming agent was set to 13.1 MPa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
A resin containing no blowing agent was not used.
[Method for Producing Extruded Foam Only of Molten Resin Containing Foaming Agent]
Foam divided into four in the thickness direction under a pressure of 6.0 MPa in the two-type seven-layer multi-layer feed block in which one non-foamed layer flow path adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the combined multi-layer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched between the upper and lower belt conveyors (I), and only the foam layer is taken up An extruded foam consisting of
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 2)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. At this time, the resin pressure at the tip of the first extruder was 11.0 MPa, while the press-fitting pressure of the foaming agent was set to 13.1 MPa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
A resin containing no blowing agent was not used.
[Method for Producing Extruded Foam Only of Molten Resin Containing Foaming Agent]
Foam divided into four in the thickness direction under a pressure of 6.0 MPa in the two-type seven-layer multi-layer feed block in which one non-foamed layer flow path adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the combined multi-layer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched between the upper and lower belt conveyors (I), and only the foam layer is taken up An extruded foam consisting of
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 3)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.4 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. At this time, the resin pressure at the tip of the first extruder was 11.3 MPa, while the press-fitting pressure of the foaming agent was set to 13.1 MPa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polystyrene (manufactured by PS Japan Co., Ltd., trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / cm ² · S · cmHg) For 100 parts by weight of resin, As a plasticizer, 4.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added to prepare a master batch in advance.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.0 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
In the feed block for the two types 7-layer multi-layer lamination temperature-controlled at 130 ° C., each of the molten resins containing the blowing agent divided into four in the thickness direction under a pressure of 5.7 MPa, Die lip that has a rectangular cross-section with a thickness of 2.0 mm and a width of 80 mm after being merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm and temperature-controlled at 80 ° C. Then, the combined multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and taken up by the apparatus (I) having the belt conveyor disposed above and below, and foamed layer / non-foamed layer / foamed layer / non-foamed An extruded foam having a five-layer structure of layer / foamed layer was obtained.
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 4)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.4 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.6 MPa, and the press injection pressure of the foaming agent was set to 13.2 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 60 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ cc · cm / cm ² · S · cmHg) and 10 parts by weight of polystyrene (manufactured by PS Japan, trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / A mixture comprising 30 parts by weight of cm ² · S · cm Hg) was dry blended to obtain a blend resin. To 100 parts by weight of the blend resin, 6.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 9.9 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion .
[How to cut the skin layer]
The obtained extruded foam was extruded on both upper and lower surfaces using a vertical slicer [manufactured by Sakura Kikai Kogyo Co., Ltd., SKH-600-1200 vertical cutting machine, band saw: width 16 × thickness 0.5 × length 7880 mm]. An extruded foam without a skin layer was obtained by cutting off a thickness of about 4 mm from the surface of the foam.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 5)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 46.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.2 MPa, and the press injection pressure of the foaming agent was set to 13.1 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 30 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ cc · cm / cm ² · S · cmHg) and 10 parts by weight of polystyrene (manufactured by PS Japan, trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / A mixture comprising 60 parts by weight of cm ² · S · cm Hg) was dry blended to obtain a blend resin. To 100 parts by weight of the blend resin, 6.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.1 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction at a pressure of 5.7 MPa in the two-type seven-layer multi-layered feed block in which one non-foamed layer flow path adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 6)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 46.2 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.2 Mpa, on the other hand, the press injection pressure of the foaming agent was set to 12.9 Mpa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹ cc · cm / cm ² · S · cmHg) To 100 parts by weight, 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.2 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 6.1 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow path adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 7)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.4 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.6 MPa, and the press injection pressure of the foaming agent was set to 13.2 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 60 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ cc · cm / cm ² · S · cmHg) and 10 parts by weight of polystyrene (manufactured by PS Japan, trade name: 679, MFR = 18 g / 10 min, air permeability = 3.9 × 10 ⁻¹⁰ cc · cm / A mixture comprising 30 parts by weight of cm ² · S · cm Hg) was dry blended to obtain a blend resin. To 100 parts by weight of the blend resin, 6.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 9.9 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 5.9 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.

(Comparative Example 8)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrene-based resin composition was supplied at 45.2 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.3 MPa, and the press injection pressure of the foaming agent was set to 13.0 MPa with respect to this.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / To 100 parts by weight of cm ² · S · cmHg), 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 9.8 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 5.9 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The evaluation results of the extruded foam obtained here are shown in Table 1.

(Comparative Example 9)
[Method for producing molten resin containing foaming agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0.1 weight with respect to 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 g / 10 min) Parts, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: calcium stearate) 0.3 parts by weight, liquid paraffin (manufactured by Shin Nippon Oil Co., Ltd., trade name: Polybutene LV-50), 0.2 parts by weight, silicon oxide A mixture of 0.1 parts by weight (manufactured by Nippon Aerosil Co., Ltd., AEROSIL) and 1.0 parts by weight of bentonite (manufactured by Southern Clay Products, Inc., Bentolite L) was dry blended to obtain a styrenic resin composition. . The styrenic resin composition was supplied at 44.3 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) For 100% by weight of the resin composition, 4.0% by weight of i-butane (manufactured by Mitsui Chemicals), 2.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.), and 0.6 parts by weight of water are melted. The resulting styrene resin composition was press-fitted. Under the present circumstances, the resin pressure in the front-end | tip of a 1st extruder was 11.6 Mpa, on the other hand, the press injection pressure of the foaming agent was set to 12.8 Mpa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into two, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder It supplied to the feed block for 7-layer multilayer lamination (made by Pla Giken Co., Ltd.).
[Method for producing molten resin containing no foaming agent]
Polyacrylonitrile (trade name: Valex 2090MN, manufactured by Mitsui Chemicals, Inc., acrylonitrile-alkyl acrylate-butadiene copolymer, MFR = 9.0 g / 10 min, air permeability = 6.5 × 10 ⁻¹² cc · cm / cm ² · S · cmHg) 30 parts by weight, styrene-acrylonitrile copolymer (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: XGS, MFR = 2.0 g / 10 min, air permeability = 4.7 × 10 ⁻¹¹⁾ A mixture consisting of 70 parts by weight of cc · cm / cm ² · S · cmHg was dry blended to obtain a blended resin. To 100 parts by weight of the blend resin, 8.0 parts by weight of dimethyl phthalate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP) was added as a plasticizer to prepare a master batch in advance.
The obtained resin was supplied to an extruder having a diameter of 50 mm at 10.3 kg / hour. The supplied resin was heated to 150 ° C., melted and kneaded, and supplied to the above-mentioned feed block for two kinds of 7-layer multi-layers without diversion.
[Method for Producing Extruded Foam by Merging Melting Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
Foam divided into four in the thickness direction under a pressure of 6.4 MPa in the above-mentioned feed block for two-layer seven-layer multi-layer lamination in which one non-foamed layer flow passage adjusted to 130 ° C. is closed. After the molten resin containing the agent is merged at a thickness of 5.2 mm / 5.2 mm / 5.2 mm / 5.2 mm, respectively, there are voids having a rectangular cross section of 2.0 mm in the thickness direction and 80 mm in the width direction. Then, from the die lip temperature-controlled at 80 ° C., the merged multilayer flow is extruded into the atmosphere, sandwiched between molding dies and pressed, and sandwiched and pulled up by the apparatus (I) where the belt conveyor is arranged up and down, and the foam layer An extruded foam having a five-layer structure of / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The evaluation results of the extruded foam obtained here are shown in Table 1.

Claims (13)

The foamed layer (A) has a plurality of structures formed by laminating the non-foamed layer (B) in the thickness direction, and is an extruded foam without a skin layer,
In the non-foamed layer (B), in accordance with JIS K7126 (2006), the temperature is 23 ° C. and the relative humidity is 0% R.D. H. Containing at least one resin whose air permeability measured under conditions is lower than the resin constituting the foam layer (A), and
In the resin having at least two non-foamed layers (B), no skin layer, the resin constituting the foamed layer (A) being a styrene resin, and constituting the non-foamed layer (B) And an extruded foam containing at least one selected from the group consisting of nitrile resins and styrene-unsaturated nitrile copolymer resins.   2. The extruded foam according to claim 1, wherein the nitrile resin contains 50% by weight or more of units derived from an unsaturated nitrile monomer in the molecule.   The nitrile resin is a nitrile resin obtained by graft copolymerization of an unsaturated nitrile and a (meth) acrylic acid alkyl ester in the presence of a conjugated diene rubber-like polymer. The extruded foam according to 1.   The styrene-unsaturated nitrile copolymer resin contains 1% by weight to less than 50% by weight of units derived from unsaturated nitrile monomers in the molecule and 50% by weight of units derived from styrene monomers. % To less than 99% by weight, The extruded foam according to any one of claims 1 to 3.   The resin constituting the non-foamed layer (B) contains a nitrile resin, and at least one resin selected from the group consisting of a styrene-unsaturated nitrile copolymer resin and a styrene resin, The extruded foam according to any one of claims 1 to 4.   The resin constituting the non-foamed layer (B) is 0.5 to 80% by weight of a nitrile resin, and 20 to 99.5% by weight of at least one selected from a styrene resin and a styrene-unsaturated nitrile copolymer resin The extruded foam according to any one of claims 1 to 5, wherein   The resin constituting the non-foamed layer (B) comprises 0.5 to 80% by weight of a nitrile resin and 20 to 99.5% by weight of a styrene-unsaturated nitrile copolymer resin. The extrusion foam in any one of -6.   When the resin constituting the non-foamed layer (B) is 100% by weight as a whole, nitrile resin 0.5 to 80% by weight, styrene-unsaturated nitrile copolymer resin 0.5 to 80% by weight and styrene The extruded foam according to claim 1, comprising 19.5 to 99% by weight of a system resin. The extruded foam according to any one of claims 1 to 8, wherein the density of the extruded foam is 20 to 100 kg / m ³ .   The at least one hydrocarbon compound selected from the group consisting of propane, n-butane, i-butane and cyclopentane is contained in the bubbles constituting the foamed layer. The extruded foam according to any one of 9. The extruded foam according to any one of claims 1 to 10, which is for a heat insulating material. A method for producing an extruded foam having a plurality of structures in which a foamed layer (A) is laminated via a non-foamed layer (B) in the thickness direction, and having no skin layer,
After the molten resin containing the foaming agent and the molten resin not containing the foaming agent are merged in the thickness direction under high pressure, it is released under atmospheric pressure, and
According to JIS K7126 (2006), a molten resin containing no foaming agent has a temperature of 23 ° C. and a relative humidity of 0% R.P. H. Containing at least one resin lower than the molten resin containing the foaming agent in the air permeability measured under the conditions; and
Resin having at least two non-foamed layers (B), removing the skin layer, and forming the foamed layer (A) is a styrenic resin, and constituting the non-foamed layer (B) It contains at least one selected from the group consisting of a nitrile-based resin and a styrene-unsaturated nitrile copolymer-based resin. The method for producing an extruded foam molded body according to claim 12, wherein the extruded foam molded body is for a heat insulating material.

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