JP2019094472A - Styrene-based resin extrusion molding - Google Patents

Abstract

To easily provide a styrene-based extrusion molding having excellent heat insulation property and flame retardancy.SOLUTION: A styrene-based resin extrusion molding contains a styrene-based resin containing a styrene-acrylonitrile copolymer, a foaming agent and a bromine-based flame retardant, in which a content of an acrylonitrile component contained in the styrene-based resin is 5 wt.% to 45 wt.% in 100 wt.% of the styrene-based resin, the foaming agent contains at least one selected from saturated hydrocarbon having 3 to 5 carbon atoms, hydrofluoroolefin and hydrochlorofluoroolefin in the total amount of 0.30 mol or more per 1 kg of the styrene-resin extrusion molding, and the bromine-based flame retardant is a bromine-based flame retardant having a molecular weight of 2,000 or less and is contained in an amount of 1.0 pts.wt. to 8.0 pts.wt. with respect to 100 pts.wt. of the styrene-based resin.SELECTED DRAWING: None

Description

  The present invention relates to a styrenic resin extruded foam obtained by extrusion foaming using a styrenic resin and a foaming agent.

  In general, a styrenic resin extruded foam is prepared by heating and melting a styrenic resin composition using an extruder or the like, then adding a foaming agent under high pressure conditions, cooling it to a predetermined resin temperature, and then subjecting it to low pressure. Manufactured continuously by extruding into a zone.

  The styrenic resin extruded foam is used, for example, as a heat insulating material of a structure from the viewpoint of good construction and heat insulation. BACKGROUND ART In recent years, the demand for energy saving of houses, buildings, etc. has been increased, and technological development of a highly heat insulating foam more than ever is desired.

  As a method for producing a highly heat insulating foam, a manufacturing method (for example, see Patent Document 1) in which graphite or titanium oxide is added in a predetermined range as a heat ray radiation inhibitor, or an ozone destruction coefficient is 0 (zero). In addition to the above, a method for producing a styrenic resin extruded foam using environmentally friendly fluorinated olefins (also referred to as hydrofluoroolefins, HFO) having a small global warming potential has been proposed (for example, patent documents 2 to 5).

  Also, in general, in polystyrene resin extruded foam, air having a high thermal conductivity penetrates into the foam's cells relatively quickly, compared to the aliphatic hydrocarbon and hydrofluoroolefin used as the foaming agent, and the heat insulating property There is a problem that is gradually decreased, and a method for producing an extruded foam using a gas barrier resin as disclosed in Patent Document 6 has also been proposed.

  On the other hand, hexabromocyclododecane (hereinafter sometimes referred to as “HBCD”), which has been widely used as a flame retardant for styrenic resin extruded foams, is a compound that is highly resistant to degradation and is highly ecological. The development of flame retardants to replace HBCD and the investigation of styrenic resin extruded foams using brominated flame retardants other than HBCD are actively conducted because they are not preferable for environmental health. There is.

  For example, as a flame retardant alternative to HBCD suitable for styrenic resin extruded foam, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether as described in Patent Documents 8 to 11, Brominated styrene as described in Patent Document 12 or a low molecular type flame retardant such as tetrabromobisphenol A-bis (2,3-dibromopropyl) ether or tris (2,3-dibromopropyl) isocyanurate Polymeric flame retardants such as butadiene block copolymers have been proposed.

JP 2013-221110 JP 2008-546892 JP 2013-194101 Special table 2010-522808 WO2015 / 093195 JP 2016-94532 WO2009 / 005984 JP-A-2017-71802 JP 2012-136674 JP 2011-021060 Japanese Patent Application Publication No. 2004-043681 Japanese Patent Application Laid-Open No. 2017-2248

  However, the techniques described in Patent Documents 1 to 12 have not been sufficient for the purpose of easily obtaining a styrenic resin extruded foam having excellent thermal insulation and flame retardancy.

  An object of the present invention is to easily obtain an extruded styrenic resin foam having excellent heat insulation and flame retardancy.

  As a result of intensive studies to solve the above problems, the present inventors have found excellent heat insulation and excellent properties which can not be achieved by the prior art by combining a specific styrenic resin and a specific brominated flame retardant. We succeeded in achieving both flame retardancy and completed the present invention.

  That is, the present invention is as the following composition.

[1] A styrenic resin extruded foam comprising a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent is at least one selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms, hydrofluoroolefins, and hydrochlorofluoroolefins in a total amount of 0.30 mol per kg of the styrene resin extruded foam. Including
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
Styrenic resin extruded foam.

[2] A styrenic resin extruded foam comprising a styrenic resin containing a styrene-acrylonitrile copolymer and a brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin,
The average cell diameter of the styrene resin extruded foam is 0.05 mm or more and less than 0.15 mm,
Styrenic resin extruded foam.

[3] A styrenic resin extruded foam comprising a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent comprises at least one selected from the group consisting of hydrofluoroolefins and hydrochlorofluoroolefins,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
Styrenic resin extruded foam.

[4] The styrenic resin extruded foam has a total content of hydrofluoroolefin and / or hydrochlorofluoroolefin of 0.30 mol or more per 1 kg of foam.
The styrene resin extruded foam according to [3].

  [5] The styrene resin extruded foam according to any one of [1] to [4], wherein the brominated flame retardant is a brominated bisphenol flame retardant and / or a brominated isocyanurate flame retardant .

[6] The brominated flame retardant is (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, (B) tetrabromobisphenol A-bis (2,3-dibromopropyl) ether And (C) at least one selected from the group consisting of tris (2,3-dibromopropyl) isocyanurate,
The styrene resin extruded foam according to any one of [1] to [5].

[7] The foaming agent contains at least one selected from the group consisting of hydrofluoroolefins and hydrochlorofluoroolefins,
The styrene resin extruded foam as described in [2].

  [8] The styrenic resin extruded foam according to [1], [3] to [4], or [7], wherein the blowing agent further contains an alkyl chloride.

[9] The content of water as a foaming agent is less than 1.0 parts by weight (including 0 parts by weight) with respect to 100 parts by weight of the styrene resin,
The styrene resin extruded foam according to any one of [1] to [8].

  [10] The styrene resin according to any one of [1] to [9], wherein the content of the styrene-acrylonitrile copolymer is 10% by weight to 100% by weight in 100% by weight of the styrene resin Extruded foam.

[11] The styrene-based resin is 0 wt% to 90 wt% of polystyrene and 10 wt% to 100 wt% of a styrene-acrylonitrile copolymer,
The styrene resin extruded foam according to any one of [1] to [10].

[12] At least one of the brominated flame retardants is (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether,
The styrene resin extruded foam according to any one of [1] to [11].

[13] The brominated flame retardant is (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, and (B) tetrabromobisphenol A-bis (2,3-dibromopropyl) ) Containing an ether, or
(A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and (C) tris (2,3-dibromopropyl) isocyanurate
The styrene resin extruded foam according to any one of [1] to [12].

[14] The brominated flame retardant comprises (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether in an amount of 25% to 75% by weight in 100% by weight of the brominated flame retardant as a whole. Including
The styrene resin extruded foam according to any one of [1] to [13].

[15] The content of the acrylonitrile component contained in the styrene-acrylonitrile copolymer is 10% by weight or more and 45% by weight or less in 100% by weight of the styrene-acrylonitrile copolymer.
The styrene resin extruded foam according to any one of [1] to [14].

[16] The black-based particles of the heat ray radiation inhibitor are contained in an amount of 0.5 parts by weight or more and 5.0 parts by weight or less based on 100 parts by weight of the styrene resin.
The styrene resin extruded foam according to any one of [1] to [15].

[17] The graphite is contained in an amount of 0.5 parts by weight or more and 5.0 parts by weight or less based on 100 parts by weight of the styrene resin.
The styrene resin extruded foam according to any one of [1] to [16].

  [18] The extruded product of the styrenic resin after heating at 170 ° C. for 10 minutes is heated at 250 ° C. for 1 hour and then dissolved in tetrahydrofuran, and the tetrahydrofuran insoluble content is 5% by weight or less, [1] The styrene-based resin extruded foam according to any one of [17].

[19] The styrene resin extruded foam according to any one of [1] to [18], wherein the apparent density of the styrene resin extruded foam is 20 kg / m ³ or more and 60 kg / m ³ or less.

  [20] The styrene resin extruded foam according to any one of [1] to [19], wherein the closed cell rate of the styrene resin extruded foam is 85% or more.

  [21] The styrene resin extruded foam according to any one of [1] or [3] to [20], wherein the average cell diameter of the styrene resin extruded foam is 0.05 mm or more and less than 0.15 mm. body.

  [22] The styrene resin extruded foam according to any one of [1] to [21], wherein the thickness of the styrene resin extruded foam is 10 mm or more and 150 mm or less.

[23] A method of extrusion-foaming a styrenic resin composition containing a styrenic resin containing a styrenic-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant to produce a styrenic resin extruded foam,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent contains at least one member selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms, hydrofluoroolefins, and hydrochlorofluoroolefins, and water is used per 100 parts by weight of the styrene resin From 0 parts by weight to less than 1.0 parts by weight,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
A method for producing a styrenic resin extruded foam.

  According to the present invention, a styrenic resin extruded foam having excellent heat insulation and flame retardancy can be easily obtained.

  Although one embodiment of the present invention is described below, the present invention is not limited to this. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims. In addition, embodiments and / or examples obtained by appropriately combining the technical means respectively disclosed in different embodiments and / or examples are also included in the technical scope of the present invention. Also, all the academic and patent documents described in the present specification are incorporated herein by reference. Moreover, unless otherwise specified in the present specification, “A to B” representing a numerical range intends “more than A (including A and greater than A) B or less (including B and less than B)”.

  As a result of intensive studies by the present inventors, it was found that the above-mentioned Patent Documents 1 to 6 have the following problems. Specifically, the methods of high thermal insulation disclosed in Patent Documents 1 to 5 are limited to suitable known heat radiation inhibitors, and the thermal conductivity is determined by the foaming agent, There is a limit to high insulation with these technologies. Furthermore, in the method of Patent Document 6, since the styrenic resin and the gas barrier resin having greatly different properties are used in combination, the material recyclability, which is one of the great advantages of styrenic resin extruded foam, is inferior.

  The present inventors first found that the heat insulation property is dramatically improved by using a styrene-acrylonitrile copolymer as a base resin as a method for solving such problems. A styrene-acrylonitrile copolymer is a resin having properties similar to polystyrene, and is superior to polystyrene in heat resistance, chemical resistance, etc., and also has slightly better gas barrier properties than polystyrene. However, the gas barrier property of the styrene-acrylonitrile copolymer is far from the gas barrier resin, for example, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyethylene terephthalate and the like. Patent document 7 similarly discloses a styrenic resin extruded foam using a styrene-acrylonitrile copolymer, but water is used for the purpose of enlarging the cell and improving the surface property of the extruded foam. It is only a means for including a specific amount, and a drastic improvement of the heat insulation as in the present invention is not suggested. Furthermore, as a result of intensive investigations by the present inventors, it was found that there are the following problems in order to use a styrene-acrylonitrile copolymer as a base resin. Specifically, when the base material resin contains a styrene-acrylonitrile copolymer, the type of brominated flame retardant to be combined is important in order to impart a suitable flame retardancy to the foam, and Depending on the type of brominated flame retardant to be used in combination, when decomposition of the brominated flame retardant proceeds, a reaction product which the styrene-acrylonitrile copolymer and the brominated flame retardant decomposed product react and does not plasticize by heat Was found to occur. According to the study of the present inventors, styrenic resin extruded foams containing an aliphatic bromine-containing polymer such as a styrene-acrylonitrile copolymer and a brominated styrene-butadiene block copolymer, in a resin mixture containing them multiple times When an excessive heat history corresponding to the passage through the extruder is applied, a reaction product not plasticized is generated by the heat, and it becomes foreign matter when producing the styrenic resin extruded foam, so that the extruded foam is obtained. It is present on the surface to impair the appearance, or is present internally to deteriorate the processability thereafter, which is a serious problem. This can not be solved even when the base resin contains the same stabilizer as the styrene resin extruded foam made only of polystyrene.

  For example, in the case of producing a styrenic resin extruded foam, generally, in order to make the extruded foam into a predetermined size, it is cut using a cutting machine, and at that time, the cutting waste of the foam is Occur. It is common among those skilled in the art to thermally reduce the volume of chips or melt and pelletize it again with an extruder and recycle it again as a raw material. As described in Patent Document 8 and Patent Document 12, it is possible to suppress the decomposition of the flame retardant at the time of recycling by adding a stabilizer, but the decomposition of the flame retardant is repeated whenever the number of times of recycling increases. It does not go a little, and it is difficult to completely eliminate decomposition. Also, for example, in order to generally start the operation of the extruder, it is necessary to wait for the temperature rise to the appropriate operation temperature and the temperature stabilization before the start of the operation. Also in this case, the resin mixture remaining in the extruder receives an excessive heat history, and if the resin mixture contains a flame retardant, decomposition naturally proceeds. Although the resin mixture remaining in the extruder at the start of the operation is usually dropped without being foamed, the above-mentioned reaction material which is not plasticized by heat is not as fluid as the base resin, so the reaction is not rapid. It is retained in the extruder without being extruded, and after a lapse of time, it mixes in the styrene resin extruded foam as foreign matter.

  As described above, the resin mixture may be subjected to an excessive heat history within the range of a general method for producing a styrenic resin extruded foam, and in that case, it is difficult to completely eliminate the decomposition of the flame retardant. In order to produce styrenic resin extruded foam stably, it is important not to generate a reaction material that does not become plasticized by heat, which becomes a foreign matter as described above, even if the flame retardant decomposes. .

  In addition, the presence or absence of the foreign material generation | occurence | production in a styrene resin extruded foam can also be discriminate | determined by the deterioration test mentioned later. In the styrenic resin extruded foam in which tetrahydrofuran (sometimes referred to as "THF") insoluble matter is present in the accelerated deterioration test, styrenic resin in the case where an excessive heat history as described above is added in the production process. For example, a large block exceeding 1 mmφ may be present on the surface or inside of the extruded foam, and / or a large number of particles may be generated, which may deteriorate the appearance and processability of the styrene resin extruded foam obtained as foreign matter.

  As in Patent Documents 8 to 11, tetrabromo is not an aliphatic bromine-containing polymer such as brominated styrene-butadiene block copolymer as a method for applying a brominated flame retardant instead of HBCD to styrenic resin extruded foam. Low molecular type such as bisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, tetrabromobisphenol A-bis (2,3-dibromopropyl) ether, tris (2,3-dibromopropyl) isocyanurate Many methods for applying flame retardants have also been proposed, but polystyrene is mainly used as a base resin, and the use of a styrene-acrylonitrile copolymer for high heat insulation is neither disclosed nor suggested. It has not been. Moreover, generation | occurrence | production of the said foreign material which arises by the combination of a styrene acrylonitrile copolymer and a specific flame retardant is not assumed.

  As described above, the prior art for producing a highly heat insulating foam has not yet been able to easily obtain a styrenic resin extruded foam having excellent heat insulation and flame retardancy, and still has problems. Met.

  The present inventors have completed the present invention in order to solve such problems.

  The styrene-based resin extruded foam according to one embodiment of the present invention is a styrene-based resin extruded foam containing a styrene-based resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a bromine-based flame retardant, The content of the acrylonitrile component contained in the styrenic resin is 5 wt% or more and 45 wt% or less in 100 wt% of the styrenic resin, and the foaming agent is a saturated hydrocarbon having 3 to 5 carbon atoms, a hydrofluoroolefin, And at least one selected from the group consisting of hydrochlorofluoroolefins in a total amount of 0.30 mol or more per kg of the styrenic resin extruded foam, and the brominated flame retardant having a molecular weight of 2000 or less And a 1.0 part by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin And wherein the Murrell.

  The extruded styrenic resin foam according to one embodiment of the present invention is a styrenic resin extruded foam containing a styrenic resin containing a styrene-acrylonitrile copolymer and a brominated flame retardant, and the styrenic resin The content of the acrylonitrile component contained therein is 5% by weight or more and 45% by weight or less in 100% by weight of the styrenic resin, and the brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, 1.0 to 8.0 parts by weight per 100 parts by weight of the styrene-based resin, and the average cell diameter of the styrene-based resin extruded foam is 0.05 mm to less than 0.15 mm I assume.

  The extruded styrenic resin foam according to one embodiment of the present invention is a styrenic resin extruded foam containing a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant. A content of an acrylonitrile component contained in the styrenic resin is 5 wt% or more and 45 wt% or less in 100 wt% of the styrenic resin, and the foaming agent is a group consisting of hydrofluoroolefin and hydrochlorofluoroolefin The brominated flame retardant is a brominated flame retardant containing at least one selected and the molecular weight is 2000 or less, and 1.0 parts by weight or more and 8.0 parts by weight with respect to 100 parts by weight of the styrene resin It is characterized by being included in part or less.

  Each of the embodiments described above may be a single configuration or may be combined with each other. Hereinafter, embodiments of the present invention will be described.

[1. Styrene resin extruded foam]
The styrenic resin extruded foam according to the present invention comprises a styrenic resin composition comprising a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant, and is contained in the styrenic resin The content of the acrylonitrile component is 5 wt% to 45 wt% with respect to 100 wt% of the styrene resin. The styrene resin composition may further contain an appropriate amount of other additives as needed, and the styrene resin composition is heated and melted using an extruder or the like, and then a foaming agent is added under high pressure conditions After cooling to a predetermined resin temperature, it is continuously produced by extruding it into a low pressure region.

  In the present invention, the content of the acrylonitrile component contained in the styrene resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene resin. The lower limit is preferably 7% by weight or more, and more preferably 10% by weight or more. On the other hand, 40 weight% or less is preferable and 35 weight% or less of an upper limit is more preferable. If the content of the acrylonitrile component contained in the styrenic resin is less than 5% by weight, the content of the acrylonitrile component is too small, so the improvement effect of the heat insulation can not be expected so much. If the content of the acrylonitrile component contained in the styrenic resin is more than 45% by weight, the amount of the acrylonitrile component is too large, so that the elongation of the resin at the time of foaming is deteriorated, which may inhibit the foaming. In addition, content of the acrylonitrile component contained in the styrene resin in this invention is content obtained by IR analysis by the method mentioned later by an Example.

  The content of the styrene-acrylonitrile copolymer in the present invention is preferably 10% by weight to 100% by weight, more preferably 25% by weight to 100% by weight, and 40% by weight to 100% by weight of 100% by weight of the styrene resin. More preferable. When the content of the styrene-acrylonitrile copolymer is less than 10% by weight, the amount of the styrene-acrylonitrile copolymer is too small, so the improvement effect of the heat insulation can not be expected so much.

  The lower limit of the amount of acrylonitrile component contained in the styrene-acrylonitrile copolymer used in the present invention is preferably 10% by weight or more, more preferably 15% by weight or more, and particularly preferably 20% by weight or more. On the other hand, 45 weight% or less is preferable, as for an upper limit, 40 weight% or less is more preferable, and 35 weight% or less is especially preferable. If the amount of acrylonitrile component contained in the styrene-acrylonitrile copolymer is less than 10% by weight, the effect of improving the heat insulation can not be expected because the amount of acrylonitrile component is too small. If the amount of the acrylonitrile component of the styrene-acrylonitrile copolymer is more than 45% by weight, the amount of the styrene component is small, so that the elongation of the resin at the time of foaming is deteriorated, which may inhibit the foaming.

  The styrene-based resin may contain a polymer having a styrene-based monomer as a constitutional unit other than the styrene-acrylonitrile copolymer, and is not particularly limited, but (i) styrene, methylstyrene, ethylstyrene A copolymer of a styrene-based monomer homopolymer such as isopropylstyrene, dimethylstyrene, bromostyrene, chlorostyrene, vinyltoluene, vinylxylene, or a combination of two or more styrene-based monomers; 1) or 2 or more types of the above-mentioned styrenic monomer and other monomers such as divinylbenzene, butadiene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, methyl methacrylate, maleic anhydride, itaconic anhydride, acrylonitrile and the like The copolymer etc. which copolymerized and, etc. are mentioned. Other monomers such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, itaconic anhydride etc. to be copolymerized with styrenic monomers are compression of styrenic resin extruded foams to be produced An amount that does not reduce physical properties such as strength can be used. In addition, the styrene resin used in one embodiment of the present invention is not limited to the homopolymer or copolymer of the styrene monomer, and a homopolymer or copolymer of the styrene monomer, It may also contain a blend of homopolymers or copolymers of the other monomers. For example, the styrenic resin used in one embodiment of the present invention may contain a blend of a homopolymer or copolymer of the styrenic monomer and a diene rubber reinforced polystyrene or an acrylic rubber reinforced polystyrene. Good. Furthermore, the styrenic resin used in the present invention is a styrenic (co) polymer having a branched structure for the purpose of adjusting melt flow rate (hereinafter referred to as MFR), melt viscosity during molding and processing, melt tension and the like. May be included.

  The styrenic resin of the present invention has a polymer having a MFR of 0.1 to 50 g / 10 min, (i) excellent molding processability when extrusion foam molding, (ii) discharge amount at the time of molding processing , The point that the thickness, width, apparent density, and closed cell ratio of the styrenic resin extruded foam obtained can be easily adjusted to a desired value, (iii) foamability (foam thickness, width, apparent density, closed cell) Rate and surface property etc. to be adjusted to the desired condition), (iv) styrenic resin extruded foam excellent in appearance etc. can be obtained, and (v) characteristics (for example, compressive strength) It is preferable from the viewpoint that a styrene-based resin extruded foam is obtained with well-balanced mechanical strength and toughness such as bending strength and bending deflection amount. Furthermore, MFR is more preferably 0.3 to 30 g / 10 min, particularly preferably 0.5 to 25 g / 10 min, in terms of balance between moldability and foamability, and mechanical strength and toughness. In the embodiment of the present invention, MFR is measured by method A of JIS K 7210-1 (2014).

  In the present invention, polystyrene is particularly preferably contained from the viewpoint of economy and processability. When higher heat resistance is required for the extruded foam, it is preferable to use (meth) acrylic acid copolymerized polystyrene and maleic anhydride-modified polystyrene. In addition, when the extruded foam is required to have higher impact resistance, it is preferable to use rubber-reinforced polystyrene. These may be used alone or in combination of two or more different styrene-based (co) polymers such as copolymer components, molecular weight, molecular weight distribution, branched structure, and / or MFR. Good.

  In the present invention, in the embodiment where polystyrene may be included in addition to the styrene-acrylonitrile copolymer, the content of polystyrene contained in 100% by weight of styrenic resin is preferably 0% by weight to 90% by weight, and 10% by weight 80 weight% is more preferable, and 20 weight% to 70 weight% is especially preferable. The content of the styrene-acrylonitrile copolymer is preferably 10% by weight to 100% by weight, more preferably 20% by weight to 90% by weight, and particularly preferably 30% by weight to 80% by weight in 100% by weight of the styrene resin. . By making the polystyrene and styrene-acrylonitrile copolymer in a styrene resin into the said range, the heat processing property improvement effect and the molding processability at the time of foaming can be compatible.

  In the present invention, a resin other than a styrene resin, for example, a nitrile resin containing an acrylonitrile component in an amount of 50% by weight or more in the base resin of the styrene resin extruded foam as long as the effects of the present invention are not impaired. The resin may be contained, but when 100% by weight of the base resin is used, the styrene resin is preferably more than 99.5% by weight, more preferably 99.7% by weight or more, and 100% by weight Particularly preferred. When the content of the resin other than the styrenic resin is 0.5% by weight or more, the elongation of the resin at the time of foaming is deteriorated, and there is a possibility that the foaming is inhibited. Moreover, there is a possibility that material recyclability as a styrene resin may be inferior.

  In one embodiment of the present invention, at least one member of the group consisting of saturated hydrocarbon having 3 to 5 carbon atoms, hydrofluoroolefin, and hydrochlorofluoroolefin is used as a blowing agent. These foaming agents may be used alone or in combination of two or more. Furthermore, in the said one Embodiment, the total amount of the foaming agent which consists of at least 1 type of a C3-C5 saturated hydrocarbon, a hydrofluoro olefin, and a hydrochloro fluoro olefin per kg of styrene resin extrusion foams 0.30 mol or more is included. The content is preferably 0.35 mol or more, and more preferably 0.40 mol or more. If the amount of the foaming agent contained in 1 kg of the styrenic resin extruded foam is less than 0.30 mol, the amount of the foaming agent contained in the styrenic resin extruded foam is too small, so the amount of air contained in the styrenic resin extruded foam Even if the amount can be reduced, the influence of air will be relatively large, and the heat insulation improvement effect can not be expected.

  In another embodiment of the invention, hydrofluoroolefins and / or hydrochlorofluoroolefins are used as blowing agents. These may be used alone or in combination of two or more. The content of the hydrofluoroolefin and / or the hydrochlorofluoroolefin is not particularly limited, but for the same reason as above, it is preferable that 0.30 mol or more is contained per 1 kg of styrenic resin extruded foam, and 0.35 mol or more is more preferable. Preferably, 0.40 mol or more is more preferable.

  Examples of the saturated hydrocarbon having 3 to 5 carbon atoms used in the present invention include propane, n-butane, i-butane, n-pentane, i-pentane, neopentane and the like. Among these saturated hydrocarbons having 3 to 5 carbon atoms, propane, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of foamability. In addition, n-butane, i-butane (hereinafter sometimes referred to as "isobutane"), or a mixture thereof is preferable from the viewpoint of the heat insulation performance of the foam, and i-butane is particularly preferable.

  The hydrofluoroolefin used in the present invention is not particularly limited, but tetrafluoropropene is preferable from the viewpoint of low gas thermal conductivity and safety. Specifically, trans-1,3,3,3-tetrafluoropropene (trans-HFO-1234ze), cis-1,3,3,3-tetrafluoropropene (cis-HFO-1234ze), 2,3, 3,3 3, 3- tetrafluoro propene (trans-HFO-1234yf) etc. are mentioned. The hydrofluoroolefin used in the present invention may be a chlorinated hydrochlorofluoroolefin. The hydrochlorofluoroolefin is not particularly limited, but hydrochlorotrifluoropropene is preferable from the viewpoint of low gas thermal conductivity and safety. Specifically, trans-1-chloro-3,3,3-trifluoropropene (trans-HCFO-1233zd) and the like can be mentioned. These hydrofluoroolefins and hydrochlorofluoroolefins may be used alone or in combination of two or more.

  The addition amount of the hydrofluoroolefin and hydrochlorofluoroolefin according to the present invention is preferably 1.0 part by weight to 14.0 parts by weight, and 2.0 parts by weight to 13.0 parts by weight with respect to 100 parts by weight of the styrene resin. Parts are more preferable, and 3.0 parts by weight to 12.0 parts by weight are particularly preferable. When the addition amount of hydrofluoroolefin and hydrochlorofluoroolefin is less than 1.0 part by weight with respect to 100 parts by weight of styrene resin, the improvement effect of the heat insulation by hydrofluoroolefin and hydrochlorofluoroolefin can not be expected so much . On the other hand, when the addition amount of hydrofluoroolefin and hydrochlorofluoroolefin exceeds 14.0 parts by weight with respect to 100 parts by weight of styrenic resin, hydrofluoroolefin and hydrochlorofluoroolefin from resin melt during extrusion foaming Separately, spot holes (hydrofluoroolefins, marks where local lumps of hydrochlorofluoroolefins burst through the surface of the extruded foam and released to the open air) are generated on the surface of the extruded foam, and closed cell rate Is likely to deteriorate the heat insulation.

  Hydrofluoroolefins and hydrochlorofluoroolefins have zero or very low ozone depletion potential and have very low global warming potential and are environmentally friendly blowing agents. In addition, since hydrofluoroolefins and hydrochlorofluoroolefins have low thermal conductivity in a gaseous state and are flame retardant, they can be used as a foaming agent for styrene resin extrusion foam to form styrene resin extrusion foam. Excellent heat insulation and flame retardancy.

  On the other hand, when a hydrofluoroolefin having a low solubility in a styrenic resin such as tetrafluoropropene is used, the hydrofluoroolefin separates from the resin melt and / or vaporizes as the amount of addition increases. The hydrofluoroolefin becomes a nucleation point by (i) the cells of the foam becoming finer, and (ii) the foaming agent remaining in the resin is reduced, and the plasticizing effect on the resin melt (Iii) cooling and solidification of the resin melt occurs due to the latent heat of vaporization of the blowing agent, and as a result, imparting a beautiful surface to the extruded foam, and It tends to be difficult to obtain thickness. In particular, as described above, when the addition amount of the hydrofluoroolefin exceeds 14.0 parts by weight with respect to 100 parts by weight of the styrene resin, the formability is deteriorated along with the generation of spot holes on the surface of the extruded foam. May be more prominent.

  Depending on the properties of the foam, such as the expansion ratio and flame retardancy, the C3-5 saturated hydrocarbon and / or the addition amount of the hydrofluoroolefin and the hydrochlorofluoroolefin are limited. If the amount is outside the desired range, extrusion foamability may not be sufficient.

  In the present invention, by using another foaming agent, a plasticizing effect and / or a co-foaming effect at the time of foam production can be further obtained, the extrusion pressure can be reduced, and foam can be stably produced. .

  Other foaming agents include, for example, ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methyl furan, tetrahydrofuran, tetrahydropyran, etc .; dimethyl ketone, methyl ethyl ketone , Diethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, methyl i-butyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone, ethyl n-propyl ketone, ethyl n-butyl ketone, etc. Ketones; C1-C4 saturated alcohols such as methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol and the like Carboxylic acid esters such as formic acid methyl ester, formic acid ethyl ester, formic acid propyl ester, formic acid butyl ester, formic acid amyl ester, propionic acid methyl ester, propionic acid ethyl ester; Organic foams such as alkyl halides such as methyl chloride and ethyl chloride Agents, water, inorganic blowing agents such as carbon dioxide, azo compounds, chemical blowing agents such as tetrazole, and the like can be used. These other foaming agents may be used alone or in combination of two or more.

  Among the other foaming agents, from the viewpoint of foamability and foam formability, saturated alcohols having 1 to 4 carbon atoms, dimethyl ether, diethyl ether, methyl ethyl ether, methyl chloride, ethyl chloride and the like are preferable, and foam is From the viewpoint of the flammability of the agent and the flame retardancy of the foam, water and carbon dioxide are preferred. Furthermore, alkyl chloride is preferable because of its large effect of improving heat insulation, and among these, methyl chloride and ethyl chloride are particularly preferable.

  When water is used as the other foaming agent, the amount of water added is preferably 0 parts by weight or more and less than 1.0 part by weight, and 0 parts by weight or more and less than 0.5 parts by weight with respect to 100 parts by weight of styrenic resin. Is more preferred. When water is added in an amount of 1.0 parts by weight or more, corrosive gas is generated by decomposition and reaction because water, alkyl chloride and a brominated flame retardant described later coexist for a long time under high temperature and high pressure in the extruder. In some cases, there is a risk that deterioration of the device may be promoted.

  The addition amount of the foaming agent in the present invention is preferably 2 parts by weight to 20 parts by weight, and more preferably 2 parts by weight to 15 parts by weight with respect to 100 parts by weight of the styrene-based resin as a whole. If the amount of the foaming agent added is less than 2 parts by weight, the expansion ratio may be low, and properties such as lightness and heat insulation as a resin foam may not be easily exhibited. If it is more than 20 parts by weight, excessive foaming is caused. Due to the amount of the agent, defects such as voids may occur in the foam.

  In the present invention, the addition amount of each foaming agent corresponds to the content of each foaming agent at the time of foaming.

  In the present invention, in the case of using water and / or alcohols as another foaming agent, it is preferable to add a water absorbing substance in order to stably perform extrusion foam molding. Specific examples of the water absorbing material include polyacrylate polymers, starch-acrylic acid graft copolymers, polyvinyl alcohol polymers, vinyl alcohol-acrylate copolymers, ethylene-vinyl alcohol copolymers Anhydrous silica (silicon oxide) having a silanol group on the surface, in addition to water-absorbent polymers such as combined, acrylonitrile-methyl methacrylate-butadiene based copolymer, polyethylene oxide based copolymer and derivatives thereof [for example, Nippon Aerosil Fine powder having a particle diameter of 1000 nm or less having hydroxyl groups on the surface, such as AEROSIL manufactured by Co., Ltd., etc .; Water-absorbing or water-swellable layered silicates such as smectite, swelling fluoromica, and the like Organized product; Zeolite, activated carbon, alumina, silica gel, porous glass , Activated clay, diatomaceous earth, porous material or the like, such as bentonite. The addition amount of the water absorbing substance is appropriately adjusted depending on the addition amount of water and / or alcohol, etc., but 0.01 part by weight to 5 parts by weight with respect to 100 parts by weight of the styrene resin Preferably, 0.1 part by weight to 3 parts by weight is more preferable.

  In the method for producing a styrenic resin extruded foam according to the present invention, the pressure at which the foaming agent is added or injected is not particularly limited as long as it is a pressure higher than the internal pressure of an extruder or the like.

  In the present invention, it is difficult to obtain the styrene resin extruded foam obtained by containing 1.0 part by weight to 10.0 parts by weight of the flame retardant with respect to 100 parts by weight of the styrene resin in the styrene resin extruded foam. Flame retardancy can be imparted. If the content of the flame retardant is less than 1.0 part by weight, good properties as foams such as flame retardancy tend not to be obtained, while if it exceeds 10.0 parts by weight, foam production The stability at the time, surface property etc. may be impaired. However, the content of the flame retardant is such as the content of the foaming agent, the apparent density of the foam, the kind of the additive having the flame retardant synergistic effect, or the like so as to obtain the flame retardancy specified in JIS A 9521 measuring method A. It is more preferable to adjust suitably according to content etc. The present invention uses a low molecular weight brominated flame retardant of 2000 or less as described later, but as far as it does not impair the effect of the present invention, it is known as a flame retardant other than the brominated flame retardant Flame retardants may be used in combination.

  The present invention is characterized by using the following brominated flame retardant as at least one of the flame retardants. The brominated flame retardant in the present invention is a low molecular type brominated flame retardant having a molecular weight of 2000 or less, and the molecular weight is preferably 1500 or less, more preferably 1000 or less. When an aliphatic bromine-containing polymer such as brominated styrene-butadiene block copolymer having a molecular weight of more than 2000, for example, a macromolecular brominated flame retardant, is used, a styrene-acrylonitrile copolymer which is not plasticized by heat There is a risk that the reaction product of the product may be generated and the appearance of the resulting foam may be impaired. By using a low molecular type bromine-based flame retardant having a molecular weight of 2000 or less, such a problem does not occur, and a suitable flame retardancy can be imparted to the styrene resin extruded foam. In the present invention, the molecular weight of the macromolecular brominated flame retardant is generally a polystyrene-equivalent number average molecular weight which can be measured by GPC.

  Specific examples of the bromine-based flame retardant in the present invention include tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether. And a brominated isocyanurate flame retardant such as tris (2,3-dibromopropyl) isocyanurate. These may be used alone or in combination of two or more.

  In the present invention, at least one of the brominated flame retardants is preferably tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether. Among them, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether as the brominated flame retardant, or Forms containing tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tris (2,3-dibromopropyl) isocyanurate are suitable for the resulting styrenic resin extruded foam It is more preferable because it can impart flame retardancy.

  In addition, the content of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether contained in the bromine-based flame retardant is 25 wt% when the entire bromine-based flame retardant is 100% by weight. % To 75% by weight is preferable.

  The reason is not clear, but when tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether contained in the brominated flame retardant is 100 wt% of the brominated flame retardant as a whole. With regard to the flame retardant performance of the resulting styrenic resin extruded foam being in the range of ̃75 wt%, the high flame retardant performance of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether is It is because if it is tetra-bisphenol-A-bis (2,3-dibromopropyl) ether or (2,3-dibromopropyl) isocyanurate which is a demerit of the mixing partner, which is a demerit of the mixing partner. Bromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether as if by itself Capable of expressing a high flame retardancy. On the other hand, with regard to the thermal stability of the resulting styrenic resin extruded foam, the content of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether having low thermal stability performance can be reduced, The thermal stability of tetrabromobisphenol A- can be increased by containing tetrabromobisphenol A-bis (2,3-dibromopropyl) ether or (2,3-dibromopropyl) isocyanurate with high thermal stability. It can be higher than using bis (2,3-dibromo-2-methylpropyl) ether alone.

  When the content of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether is less than 25% by weight, based on 100% by weight of the entire brominated flame retardant, the flame retardancy obtained Tends to be low, and when it exceeds 75% by weight, the thermal stability tends to deteriorate.

  When it is intended to stably obtain higher flame retardancy and higher thermal stability in consideration of the dispersion and variation of the flame retardant in the styrene resin, tetrabromobisphenol A-bis (2,2, The content of 3-dibromo-2-methylpropyl) ether is preferably in the range of 35% by weight to 65% by weight.

  Content of the brominated flame retardant in the styrene resin extruded foam according to the present invention is 1.0 part by weight or more and 8.0 parts by weight or less with respect to 100 parts by weight of the styrene resin, and 100 parts by weight of the styrene resin 1.5 parts by weight or more is preferable, and 2.0 parts by weight or more is more preferable. On the other hand, 7.0 parts by weight or less is preferable, and 6.0 parts by weight or less is more preferable. If the content of the brominated flame retardant is less than 1.0 part by weight, good properties as foams such as flame retardancy tend to be difficult to obtain, while if it exceeds 8.0 parts by weight, the foam is generated. In some cases, the stability during production, surface properties, etc. may be impaired.

  In the present invention, a radical generator can be used in combination for the purpose of improving the flame retardant performance of the styrenic resin extruded foam. Specifically, the radical generator is 2,3-dimethyl-2,3-diphenylbutane, poly-1,4-diisopropylbenzene, 2,3-diethyl-2,3-diphenylbutane, 3,4- Dimethyl-3,4-diphenylhexane, 3,4-diethyl-3,4-diphenylhexane, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, etc. Can be mentioned. Peroxides such as dicumyl peroxide are also used. Among them, those stable at resin processing temperature conditions are preferable, and specifically, 2,3-dimethyl-2,3-diphenylbutane and poly-1,4-diisopropylbenzene are preferable, and The preferable addition amount is 0.05 parts by weight to 0.5 parts by weight with respect to 100 parts by weight of the styrene resin.

  Furthermore, in order to improve the flame retardant performance, in other words, as a flame retardant auxiliary, it is possible to use a phosphorus based flame retardant such as a phosphate and phosphine oxide in combination as long as the heat stability is not impaired. Examples of phosphoric acid esters include triphenyl phosphate, tris (tributylbromoneopentyl) phosphate, tricresyl phosphate, trixarylenyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, Examples thereof include tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, condensed phosphoric acid esters and the like, and in particular, triphenyl phosphate or tris (tributylbromoneopentyl) phosphate is preferable. Moreover, as a phosphine oxide type phosphorus flame retardant, triphenyl phosphine oxide is preferable. These phosphoric acid esters and phosphine oxides may be used alone or in combination of two or more. The preferable addition amount of the phosphorus-based flame retardant is 0.1 parts by weight to 2 parts by weight with respect to 100 parts by weight of the styrene-based resin.

  In the present invention, a stabilizer for a resin and / or a flame retardant can be used as needed. Although not particularly limited, specific examples of the stabilizer include (i) epoxy compounds such as bisphenol A diglycidyl ether type epoxy resin, cresol novolac type epoxy resin, and phenol novolac type epoxy resin, ii) A reaction product of a polyhydric alcohol such as pentaerythritol, dipentaerythritol or tripentaerythritol and a monovalent carboxylic acid such as acetic acid or propionic acid or a divalent carboxylic acid such as adipic acid or glutamic acid An ester, which is a mixture of esters having one or more hydroxyl groups in its molecule, and which may contain a small amount of polyhydric alcohol as a raw material, (iii) Triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylpheny ) Propionate, pentaerythritol tetrakis [3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate], and octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Phenolic stabilizers such as propionate, (iv) 3,9-bis (2,4-di-tert-butylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] Undecane, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, and tetrakis Phosphies such as 2,4-di-tert-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite) System stabilizers, etc. without reducing the flame retardancy of the foam, and, since it improves the thermal stability of the foam, is preferably used.

  The extruded styrene-based resin foam according to the present invention may contain a heat ray radiation inhibitor for the purpose of improving heat insulation. The heat ray radiation suppressing agent refers to a substance having the property of reflecting, scattering, and absorbing light in the near infrared or infrared region. By containing a heat ray radiation inhibitor, it can become a foam which has high thermal insulation. Examples of the heat ray radiation inhibitor include black particles such as graphite and carbon black and activated carbon, and white particles such as titanium oxide, barium sulfate, zinc oxide, aluminum oxide and antimony oxide. These may be used alone or in combination of two or more. Among these, graphite and carbon black are preferable in black particles because graphite has a high heat radiation suppression effect, and graphite is more preferable. Further, in the white particles, titanium oxide and barium sulfate are preferable, and titanium oxide is more preferable.

  As the graphite in the present invention, for example, flaky graphite, earthy graphite, spherical graphite, artificial graphite and the like can be mentioned. Among these, from the viewpoint of high heat ray radiation suppression effect, it is preferable to use a material whose main component is flaky (piece) like graphite. The graphite preferably has a fixed carbon content of 80% or more, more preferably 85% or more. By making fixed carbon content into the said range, the foam which has high thermal insulation is obtained.

  The average particle diameter of the black-based particles in the present invention is not particularly limited, but in the case of graphite, for example, 15 μm or less is preferable, and 10 μm or less is more preferable. Moreover, if it is carbon black, 0.3 micrometer or less is preferable, and 0.1 micrometer or less is more preferable. By setting the average particle diameter to the above range, the specific surface area of the graphite becomes large, and the collision probability with the heat ray radiation becomes high, so the heat ray radiation suppression effect becomes high. The average particle size is determined by measuring and analyzing the particle size distribution by the laser diffraction scattering method based on Mie theory based on ISO13320: 2009, JIS Z8825: 2013, and the particle size when the cumulative volume with respect to the volume of all particles is 50% It means (volume average particle diameter by laser diffraction scattering method).

  The content of the black particles in the present invention is preferably 0.5 parts by weight or more and 5.0 parts by weight or less, and more preferably 1.0 parts by weight or more and 3.0 parts by weight or less based on 100 parts by weight of the styrene resin . If the content is less than 0.5 parts by weight, there is a tendency that a sufficient heat radiation suppression effect can not be obtained. If the content is more than 5.0 parts by weight, the heat ray radiation suppression effect corresponding to the content may not be obtained, and there may be no cost merit.

  The average particle size of the white-based particles in the present invention is not particularly limited, but in the case of effectively reflecting infrared rays and considering the color developability to the resin, for example, 0.1 μm to 10 μm for titanium oxide Is preferable, and 0.15 μm to 5 μm is more preferable.

  The content of the white-based particles in the present invention is preferably 1.0 part by weight to 3.0 parts by weight, and more preferably 1.5 parts by weight to 2.5 parts by weight with respect to 100 parts by weight of the styrene resin. . White-based particles have a smaller effect of suppressing heat ray radiation than black-based particles, and if the content of white-based particles is less than 1.0 part by weight, even if they contain the above-mentioned white-based particles, there is almost no effect of suppressing heat ray radiation. . When the content of the white-based particles is more than 3.0 parts by weight, the heat ray radiation suppression effect corresponding to the content can not be obtained, while the flame retardancy of the foam tends to be deteriorated.

  The total content of the heat ray radiation inhibitor in the present invention is preferably 0.5 parts by weight to 6.0 parts by weight, and more preferably 2.0 parts by weight to 5.0 parts by weight with respect to 100 parts by weight of the styrene resin. preferable. If the total content of the heat ray radiation inhibitor is less than 0.5 parts by weight, it is difficult to obtain heat insulation, while the nucleation point increases as the content of solid additives such as the heat ray radiation inhibitor increases. However, it tends to be difficult to impart a beautiful surface to the extruded foam and to make the thickness of the extruded foam difficult, because the cells of the foam become finer or the elongation of the resin itself is deteriorated. When the total content of the heat ray radiation suppression agent is more than 6.0 parts by weight, in particular, imparting a beautiful surface to the extruded foam and producing a thickness of the extruded foam tend to be inferior, and further, There is a tendency to impair the extrusion stability and to impair the flame retardancy.

  In the present invention, if necessary, further, as long as the effects of the present invention are not inhibited, for example, inorganic compounds such as silica, calcium silicate, wollastonite, kaolin, clay, mica, calcium carbonate, sodium stearate Processing aids such as calcium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, etc., phenolic antioxidant, phosphorus stabilizer, nitrogen stabilizer, sulfur stabilizer, Light-resistant stabilizers such as benzotriazoles and hindered amines, cell diameter regulators such as talc, moldability improvers such as polyethylene glycol and polyhydric alcohol fatty acid ester, antistatic agents other than the above, colorants such as pigments, etc. An additive may be contained in the styrenic resin.

  As a method and procedure of blending various additives with a styrene resin, for example, a method of adding various additives to a styrene resin and mixing them by dry blending, melted from a supply part provided in the middle of an extruder Method of adding various additives to styrenic resin, prepare a master batch in which various additives of high concentration are added to styrenic resin using extruder, kneader, Banbury mixer, roll and the like beforehand, A method of mixing with a styrene resin by dry blending, or a method of supplying various additives to an extruder by a supply facility other than the styrene resin may, for example, be mentioned. For example, after adding and mixing various additives with styrene resin, it supplies to an extruder, heat-melts, and also the procedure of adding and mixing a foaming agent is mentioned, but various additives or a foaming agent is mentioned. There are no particular limitations on the timing of adding the styrene to the styrene resin and the kneading time.

  The thermal conductivity of the styrenic resin extruded foam according to the present invention is not particularly limited, but it is, for example, a heat insulating material in consideration of functioning as a heat insulating material for construction or a heat insulating material for cold storage or cold storage car. Therefore, the thermal conductivity after one week of production measured at an average temperature of 23 ° C. is preferably 0.0284 W / m K or less, more preferably 0.0244 W / m K or less, and 0.0224 W / m K or less Being particularly preferred.

The apparent density of the styrenic resin extruded foam according to the present invention is preferably, for example, from the viewpoint of heat insulation and lightness considering the function as a heat insulating material for construction or a heat insulating material for cold storage or cold storage vehicles. Is 20 kg / m ³ or more, more preferably 25 kg / m ³ or more. On the other hand, 60 kg / m < ³ > or less is preferable and 50 kg / m < ³ > or less is more preferable.

  85% or more is preferable and 90% or more of the closed cell rate of the styrene resin extruded foam concerning this invention is more preferable. If the closed cell rate is less than 85%, the foaming agent may be dissipated early from the extruded foam, and the heat insulation may be reduced.

  In the styrene resin extruded foam according to one embodiment of the present invention, the average cell diameter in the thickness direction of the styrene resin extruded foam is preferably 0.05 mm or more and less than 0.15 mm, and 0.05 mm or more and 0.13 mm or less Is more preferable, and 0.05 mm or more and 0.10 mm or less is particularly preferable. In general, the smaller the average cell diameter, the shorter the distance between cell walls of the foam, so that the movable range of the cells of the extruded foam at the time of shaping the extruded foam during extrusion foaming is narrow and deformation is difficult It tends to be difficult to apply a beautiful surface to the extruded foam and to obtain the thickness of the extruded foam. When the average cell diameter in the thickness direction of the styrenic resin extruded foam is smaller than 0.05 mm, in particular, it tends to be difficult to impart a beautiful surface to the extruded foam and to make the thickness of the extruded foam difficult. It becomes a thing. On the other hand, when the average cell diameter in the thickness direction of the styrene resin extruded foam is 0.15 mm or more, there is a possibility that sufficient heat insulation can not be obtained.

  The average cell diameter of the extruded styrenic resin foam according to the present invention is evaluated as described below using a microscope [DIGITAL MICROSCOPE VHX-900, manufactured by KEYENCE CORPORATION].

  Width direction vertical cross section of thickness direction center of a total of three places of 150 mm in the width direction center part of the obtained styrene resin extruded foam and 150 mm in the opposite end direction from the one end in the width direction (the same place at both ends in the width direction) The sample was observed with the microscope from the extrusion direction and the width direction, and a 100 × magnified image was taken. Three three straight lines of 2 mm are arbitrarily drawn in the thickness direction of the enlarged photograph (each observation location, three lines in each observation direction), and the number a of bubbles contacting the straight line is measured. From the number a of bubbles thus measured, the average bubble diameter A in the thickness direction for each observation point was determined by the following equation (1). The average value of three locations (two directions in each location) is taken as the average cell diameter A (average value) in the thickness direction of the extruded styrenic resin foam.

Average bubble diameter A (mm) in the thickness direction for each observation point = 2 × 3 / number of bubbles a
... (1)

  Extrusion direction perpendicular cross section of thickness direction central part in total of the width direction central part of the obtained styrenic resin extruded foam and a place of 150 mm in the opposite end direction from one end in the width direction (the same place at both ends in the width direction) Is observed from the width direction with the microscope, and a 100 × magnified photograph is taken. Three three straight lines of 2 mm are arbitrarily drawn in the extrusion direction of the enlarged photograph (three lines for each observation point), and the number b of bubbles contacting the straight line is measured. From the measured number b of bubbles, the average bubble diameter B in the extrusion direction for each observation point is determined by the following equation (2). Let the average value of three places be the average cell diameter B (average value) of the extrusion direction of the styrene resin extruded foam.

Average bubble diameter B in the extrusion direction for each observation point B (mm) = 2 x 3 / number of bubbles b
... (2)

  Width direction vertical cross section of thickness direction center of a total of three places of 150 mm in the width direction center part of the obtained styrene resin extruded foam and 150 mm in the opposite end direction from the one end in the width direction (the same place at both ends in the width direction) And observed with the microscope from the extrusion direction, and taking a 100 × magnified photograph. Three three straight lines of 2 mm are arbitrarily drawn in the width direction of the enlarged photograph (three for each observation point), and the number c of bubbles contacting the straight line is measured. From the measured number c of bubbles, an average bubble diameter C in the width direction at each observation point is determined by the following equation (3). Let the average value of three places be the average cell diameter C (average value) of the width direction of a styrene resin extrusion foam.

Average bubble diameter C in the width direction for each observation point C (mm) = 2 x 3 / number c of bubbles
... (3)

  The value obtained by arithmetically averaging the average cell diameter A in the thickness direction, the average cell diameter B in the extrusion direction, and the average cell diameter C in the width direction determined as described above is the average cell diameter of the styrenic resin extruded foam Do.

  0.7 or more and 2.0 or less are preferable, 0.8 or more and 1.5 or less are more preferable, and 0.8 or more and 1.2 or less are still more preferable. . If the cell deformation rate is less than 0.7, the compressive strength is low, and there is a possibility that the extruded foam can not have a strength suitable for the application. In addition, since the cells tend to return to spherical shape, the size (shape) maintainability of the extruded foam tends to be poor. On the other hand, when the cell deformation ratio exceeds 2.0, the number of cells in the thickness direction of the extruded foam decreases, so the heat insulation improving effect by the cell shape decreases.

  In addition, the cell deformation rate of the styrene resin extruded foam according to the present invention can be obtained from the above-described average cell diameter by the following formula (4).

  Bubble deformation rate (no unit) = A (average value) / {[B (average value) + C (average value)] / 2} (4)

  The thickness of the extruded styrenic resin foam according to the present invention is, for example, from the viewpoint of heat insulation, bending strength and compression strength considering that it functions as a heat insulating material for construction or a heat insulating material for cold storage or cold storage vehicles. It is preferable that it is 10 mm-150 mm, More preferably, it is 20 mm-130 mm, Most preferably, it is 20 mm-120 mm.

  In the styrene resin extruded foam, as described in the examples of the present invention and the comparative examples, both surfaces of a flat surface perpendicular to the thickness direction are formed on one side in the thickness direction after extrusion foam molding to give a shape. The product thickness may be cut at a depth of about 5 mm to make the product thickness, but unless otherwise stated, the thickness of the styrene resin extruded foam according to the present invention is a cut as it is given by extrusion foam molding. It is not about the thickness.

  The styrene resin extruded foam according to the present invention has a tetrahydrofuran insoluble matter content of 1% by weight or less containing a component derived from a styrene-acrylonitrile copolymer in a deterioration acceleration test of a styrene resin extruded foam described later. Is preferred. The THF insoluble matter corresponds to a reactant which is not plasticized by the heat generated by the reaction of the styrene-acrylonitrile copolymer described above and the brominated flame retardant. In the styrenic resin extruded foam in which the THF insoluble content is present in excess of 1% by weight in the accelerated deterioration test, the styrenic resin extruded foam is obtained when an excessive heat history as described above is added in the manufacturing process. For example, it may be present as a large block exceeding 1 mmφ on the surface or in the inside and / or a large number of particles may be generated, which may deteriorate the appearance and processability of the styrene resin extruded foam obtained as foreign matter. Reactants that are not plasticized by heat are usually yellow or brown, although the color density changes depending on the progress of the reaction, but they are styrenic resins containing additives that have coloring properties such as graphite and pigments. In the extruded foam, since the reaction product which is not plasticized by the above-mentioned heat entraps these additives and colors strongly, when it exists as a foreign material in the styrenic resin extruded foam, the appearance is particularly impaired. The details of the method of the accelerated deterioration test according to the present invention will be described later in Examples.

  Thus, according to the present invention, a styrenic resin extruded foam having excellent heat insulation and flame retardancy can be easily obtained.

[2. Method for producing styrenic resin extruded foam]
The method for producing a styrenic resin extruded foam described below is one of the preferred embodiments used for producing the styrenic resin extruded foam of the present invention. Among the constitutions in the method for producing a styrene resin extruded foam, [1. The description of the configuration already described in the section “Styrenic resin extruded foam” is omitted here.

  In a preferred embodiment of the method for producing a styrenic resin extruded foam, a styrenic resin, a brominated flame retardant, and, if necessary, a stabilizer, a heat ray radiation inhibitor, or any other additive, an extruder, etc. Etc. It supplies to the heating fusion part of At this time, the blowing agent can be added to the styrenic resin under high pressure conditions at any stage. Then, a mixture containing a styrenic resin, a brominated flame retardant, and a foaming agent is used as a fluid gel, cooled to a temperature suitable for extrusion foaming, and the fluid gel is extruded and foamed through a die to form a foam. Do.

  The heating temperature in the heating and melting portion may be a temperature at which the styrenic resin to be used melts, but a temperature at which molecular degradation of the resin due to the influence of additives and the like is suppressed as much as possible, for example 150 ° C to 260 ° C The degree is preferred. The melting and kneading time in the heating and melting part is uniquely defined because it varies depending on the extrusion amount of styrenic resin per unit time and / or the type of extruder used as the heating and melting part and used as the melting and kneading part The time required for the styrene resin and the foaming agent and the additive to be uniformly dispersed and mixed can not be set appropriately.

  As a melt-kneading part, although a screw-type extruder etc. are mentioned, for example, it will not restrict | limit especially if it is what is used for normal extrusion foaming.

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

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

  Hereinafter, examples of the present invention will be described. Of course, the present invention is not limited to the following examples.

  The raw materials used in the examples and comparative examples are as follows.

○ Base resin · styrenic resin A [Styrene-acrylonitrile copolymer; Denka Co., Ltd., Denka AS GR-AT-5S; acrylonitrile content 25 wt%, MFR 8.0 g / 10 min]
Styrene resin B [Styrene-acrylonitrile copolymer; Denka AS Co., Ltd., Denka AS AS-EXS; acrylonitrile content: 25% by weight, MFR 2.1 g / 10 min]
Styrene resin C [Styrene-acrylonitrile copolymer; Denka AS Co., Ltd., Denka AS AS-XGS; acrylonitrile content: 28% by weight, MFR 2.1 g / 10 min]
Styrene resin D [polystyrene; PS Japan Co., Ltd. G9401; MFR 2.2 g / 10 min]
○ Heat ray radiation inhibitor, graphite [Maruho Casting Co., Ltd., M-885; flake-like graphite, primary particle size 5.5 μm, fixed carbon content 89%]
○ Flame retardant · Tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether (brominated flame retardant) [Daiichi Kogyo Seiyaku Co., Ltd., SR-130, molecular weight 972]
・ A mixed brominated flame retardant of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether [Daiichi Kogyo Seiyaku Co., Ltd. ), GR-125P, molecular weight 972/952]
Brominated styrene-butadiene block polymer [manufactured by Chemtura, EMERALD INNOVATION # 3000, number average molecular weight 140000]
○ Flame retardant aid, triphenyl phosphine oxide [Sumitomo Shoji Chemical]
○ Radical generator, poly-1,4-diisopropylbenzene (manufactured by UNITED INITIATORS, CCPIB)
○ Stabilizer-Bisphenol-A-glycidyl ether [ADEKA CORPORATION, EP-13]
Cresol novolak epoxy resin [Huntsman Japan, ECN-1280]
-Dipentaerythritol-adipic acid reaction mixture [Ajinomoto Fine Techno Co., Ltd. product, Plenizer ST210]
-Pentaerythritol tetrakis [3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] [manufactured by Chemtura, ANOX 20]
・ 3,9-bis (2,4-di-tert-butylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane [manufactured by Chemtura, Ultranox 626]
Triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate [Songwon Japan Co., Ltd., Sonnox 2450FF]
○ Other additives
-Talc [Hayashi Kasei Co., Ltd., Talkan Powder PK-Z]
· Calcium stearate [SC-P, manufactured by Sakai Chemical Industry Co., Ltd.]
・ Bentite [Hohjun Co., Ltd., bengel bright 11K]
Silica [Evonik Degussa Japan Co., Ltd., Carplex BS-304F]
・ Ethylene bis-stearic acid amide (manufactured by NOF Corporation, Alflo H-50S)
・ Stearic acid monoglyceride [manufactured by Riken Vitamin Co., Ltd., Rikemar S-100P]
○ Foaming agent · HFO-1234ze [Hanewell Japan KK]
・ Dimethyl ether [Iwataya Sangyo Co., Ltd. product]
・ Isobutane [Mitsui Chemical Co., Ltd. product]
-Ethyl chloride [Nippon Special Chemical Industry Co., Ltd. product]
・ Water [Osaka Prefecture Settsu City tap water]
Regarding physical properties of extruded foams according to Examples and Comparative Examples, thickness (before cut) of styrenic resin extruded foam, acrylonitrile content in styrenic resin, foam per 1 kg of styrenic resin extruded foam according to the following method The agent content, apparent density, closed cell rate, average cell diameter, cell deformation rate, thermal conductivity, JIS flammability, deterioration accelerated test were evaluated and carried out.

(1) Thickness of styrenic resin extruded foam (before cut)
Using a vernier caliper [M-type standard vernier caliper N30 made by Mitutoyo Corp., thickness of 150 mm in the widthwise center and 150 mm from the one end to the opposite end from the one end in the width direction (the same place at both ends in the width direction) Was measured. The average value of three points was taken as the thickness of the styrene resin extruded foam.

(2) Acrylonitrile Content in Styrene-Based Resin The styrene-based resin extruded foam IR obtained was analyzed under the following conditions.

-Device; FT-IR [Perkin Elmer, spectrometer model Spectrum One]
・ Measurement range: 4000-400 cm ^-1
・ Detector; DTGS
-Number of integrations: 4 times-Resolution: 4.00 cm ^-1
In the obtained analysis results, the acrylonitrile content (% by weight) was determined from the absorbance derived from the acrylonitrile derived peak appearing around 2240 cm ⁻¹ and the styrene derived peak appearing around 1600 cm ⁻¹ .

(3) Foaming agent content per 1 kg of styrenic resin extruded foam The obtained styrenic resin extruded foam is classified into a standard temperature state class 3 (23 ° C. ± 5 ° C.) specified in JIS K 7100, and a standard humidity state It was allowed to stand under tertiary conditions (50 ^{+ 20, -10} % RH), and the HFO-1234ze content and isobutane content 7 days after production were evaluated by the following equipment and procedures.
a) Equipment used; gas chromatograph GC-2014 [manufactured by Shimadzu Corporation]
b) Column used; G-Column G-950 25 UM (manufactured by Chemical Evaluation and Research Organization)
c) Measurement conditions;
・ Inlet temperature: 65 ° C
・ Column temperature: 80 ° C
・ Detector temperature: 100 ° C
Carry gas: High purity helium Carry gas flow rate: 30 mL / min Detector: TCD
・ Current: 120 mA
About 1.2 g of test pieces are placed in an approximately 130 cc sealable glass container (hereinafter referred to as "sealed container") depending on the apparent density cut out from the foam, and the air in the sealed container is evacuated by a vacuum pump. The Thereafter, the closed vessel was heated at 170 ° C. for 10 minutes, and the foaming agent in the foam was taken out into the closed vessel. After the closed vessel returns to normal temperature, introduce helium into the closed vessel and return to atmospheric pressure, then take out a mixed gas containing 40 μL of HFO-1234ze and isobutane with a microsyringe, and use of above a) to c) The equipment was evaluated under the measurement conditions.

(4) Apparent density (kg / m ³ )
The weight of the resulting styrenic resin extruded foam was measured, and the length dimension, width dimension, and thickness dimension were measured.

From the measured weight and each dimension, the foam density was determined based on the following equation (5), and the unit was converted to kg / m ³ .
Apparent density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ ) (5)
(5) Independent cell rate 40 mm in thickness from a total of three locations in the width direction central portion of the obtained styrene resin extruded foam, and 150 mm in the opposite end direction from one end in the width direction (the same place at both ends in the width direction) (However, products with product thickness less than 40 mm were left as product thickness) Measured according to procedure C of ASTM-D 2856-70 using test pieces cut into length (extrusion direction) 25 mm × width 25 mm. The independent cell rate of each test piece is determined by the following calculation formula (6), and the average value of three points is taken as the independent cell rate of the styrene resin extruded foam.
Closed cell ratio (%) = (V1-W / ρ) × 100 / (V2-W / ρ) (6)
Here, V1 (cm ³ ) is the true volume of the test piece measured using an air comparison type specific gravity meter (manufactured by Tokyo Science Co., Ltd., air comparison type specific gravity meter, model 1000 type) Is excluded). V2 (cm ³ ) is an apparent volume calculated from an outer dimension of a test piece measured using a vernier caliper [M-type standard caliper N30 manufactured by Mitutoyo Corp.]. W (g) is the total weight of the test piece. Also, ρ (g / cm ³ ) is the density of the styrenic resin constituting the extruded foam, and polystyrene is 1.05 (g / cm ³ ), and the styrene-acrylonitrile copolymer is 1.07 (g / cm) ³ ), and calculated and used according to the weight ratio (% by weight) of each contained in the styrenic resin.

(6) Average cell diameter in the thickness direction and cell deformation rate The obtained styrene resin extruded foam was evaluated as described above.

(7) Thermal conductivity According to JIS A 9521, using a test piece cut into thickness product thickness x length (extrusion direction) 300 mm x width 300 mm, a thermal conductivity measuring apparatus [Eiko Seiki Co., Ltd., HC- The thermal conductivity at an average temperature of 23 ° C. was measured at 074]. For measurement, after producing a styrenic resin extruded foam, it is cut into a test piece of the above dimensions, and the standard temperature state class 3 (23 ° C. ± 5 ° C.) specified in JIS K 7100, and the standard humidity state class 3 (50 It left still under the conditions of ^{+20 and -10} % RH and it carried out one week after manufacture.

(8) JIS Flammability According to JIS A 9521, using the test piece of thickness 10 mm x length 200 mm x width 25 mm, the following criteria evaluated. For measurement, after producing a styrenic resin extruded foam, it is cut into a test piece of the above dimensions, and the standard temperature state class 3 (23 ° C. ± 5 ° C.) specified in JIS K 7100, and the standard humidity state class 3 (50 It left still under the conditions of ^{+20 and -10} % RH and it carried out one week after manufacture.
○: The flame goes out within 3 seconds, there is no residue, and the criteria for not burning beyond the limit line are met.
X: The above criteria are not met.

(9) Deterioration accelerated test A test piece is cut out from the obtained styrene resin extruded foam, and heated at 170 ° C. for 10 minutes in a drier [Yamato Scientific Co., Ltd., fine oven DH-42] to remove the foaming agent. About 1.0 g was used as a sample. Further, this sample was heated at 250 ° C. for 1 hour in a drier to obtain a degraded sample.

  The whole amount of the degraded sample obtained was introduced into 50 mL of THF measured in a screw tube of an appropriate size so that the entire degraded sample was immersed, and the screw tube was sealed. The screw tube containing the degraded sample and THF was irradiated with ultrasonic waves for 10 minutes using an ultrasonic cleaner [As One Corp., ultrasonic cleaner USM (oscillation frequency: 42 kHz)]. The screw tube was removed from the ultrasonic cleaner and allowed to stand for 24 hours to obtain a THF solution of a deteriorated sample.

  Then, the THF solution of the deteriorated sample was filtered through a membrane filter with a pore size of 1.0 μm, and further washed with THF, and the residue which did not pass through the membrane filter was dried in a dryer at 100 ° C. for 24 hours.

The weight of the residue after drying is measured, and the weight of the contained inorganic substance is subtracted from the measured weight to obtain the weight of the THF insoluble matter, and the THF insoluble matter content (% by weight) is determined by calculation formula (7). It evaluated by. THF insoluble content (% by weight)
= THF insolubles weight (g) / sample weight (g) x 100 ... (7)
◎: THF insoluble content is 1% by weight or less.
○: THF insoluble content is more than 1% by weight and 5% by weight or less.
X: THF insoluble content is more than 5% by weight.

  The weight of the inorganic substance contained in the residual substance may be calculated as the blending of the styrenic resin extruded foam excluding the foaming agent, but in the case of unknown, for example, it may be analyzed as follows.

  A test piece is cut out of the styrenic resin extruded foam, and heated at 170 ° C. for 10 minutes with a drier to remove about 10 mg of the foaming agent as a sample. This sample was subjected to a thermal analysis system: EXSTAR 6000 using a thermogravimetry apparatus (SAI Nanotechnology Inc., TG / DTA 220U) under a nitrogen stream of 200 mL / min from 40 ° C. to 600 ° C. 20 The temperature is increased at a rate of ° C./min and then maintained at 600 ° C. for 10 minutes, and the weight loss amount at this time is calculated as the amount of organic matter and the amount of inorganic matter otherwise.

  When it is difficult to determine that the THF insoluble matter is a substance derived from the base resin, the THF insoluble matter may be separately analyzed by IR or NMR.

  For the examples and comparative examples, the graphite was added by means of a masterbatch made according to the following procedure.

(Production Example 1) [Production of Graphite Master Batch A]
In a Banbury mixer, 100 parts by weight of a styrene-based resin A (styrene-co-acrylonitrile copolymer, Denka Co., Ltd., Denka AS GR-AT-5S), which is a base resin, and 100 parts by weight of a styrene-based resin A 102 parts by weight of graphite [M-885, manufactured by Maru Toyo Casting Mfg Co., Ltd.], and 2.0 parts by weight of ethylenebisstearic acid amide (manufactured by NOF Corporation, Alflo H-50S) and 20 minutes melt-kneaded without heating and cooling under a load of 5 kgf / cm ^2. At this time, when the resin temperature was measured, it was 185.degree. The strand resin extruded at a discharge rate of 250 kg / hr was cooled and solidified in a water bath at 30 ° C. through a die having a small hole attached to the tip of a ruder and then cut to obtain a graphite master batch A. .

(Production Example 2) [Production of Graphite Master Batch B]
In the same manner as in Production Example 1 except that styrene-based resin B [styrene-acrylonitrile copolymer; Denka Co., Ltd., Denka AS AS-EXS] is used instead of styrene-based resin A. The graphite master batch B was obtained.

(Production Example 3) [Production of Graphite Masterbatch C]
Production Example 1 is the same as Production Example 1 except that in place of styrene resin A, styrene resin C (styrene-acrylonitrile copolymer; Denka Co., Ltd. product Denka AS AS-XGS) is used. A graphite master batch C was obtained in the same manner.

(Production Example 4) [Production of Graphite Master Batch D]
A graphite master batch D was obtained in the same manner as in Production Example 1 except that, in Production Example 1, a styrene resin D [polystyrene; G9401 manufactured by PS Japan Co., Ltd.] was used instead of the styrene resin A. .

Example 1
[Preparation of resin mixture]
100 parts by weight of a styrenic resin A [styrene-acrylonitrile copolymer; Denka AS GR-AT-5S], which is a base resin, and tetrabromobisphenol A-bis (2, 3 as a flame retardant) -A mixed brominated flame retardant (made by Dai-ichi Kogyo Seiyaku Co., Ltd., GR-125P) of dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether 3.0 weight Parts, triphenyl phosphine oxide as a flame retardant auxiliary [Sumitomo Shoji Chemical] 1.0 parts by weight, talc as a cell size regulator, 3.0 parts by weight of talc [Hayashi Kasei Co., Ltd., Talcan Powder PK-Z], stabilizer And 0.20 parts by weight of bisphenol-A-glycidyl ether (manufactured by ADEKA Co., Ltd., EP-13), triethylene glycol-bis- 0.20 parts by weight of (3-t-butyl-4-hydroxy-5-methylphenyl) propionate [Songwon Japan Ltd., Sonnox 2450FF], dipentaerythritol-adipic acid reaction mixture [Ajinomoto Finetechno, 0.10 parts by weight of Plenlyzer ST210, 0.20 parts by weight of calcium stearate [Sho Chemical Industry Co., Ltd., SC-P] as a lubricant, and stearic acid monoglyceride as a formability improving agent [Riken Vitamins Co., Ltd.] Dry blend of 0.50 parts by weight of Rikemar S-100P] was carried out.

[Production of extruded foam]
The obtained resin mixture is transferred to a single screw extruder (first extruder) with a bore of 150 mm, a single screw extruder with a bore of 200 mm (second extruder), and an extruder in which a cooler is connected in series with 950 kg / hr. Supplied with The resin mixture supplied to the first extruder is heated to a resin temperature of 250 ° C. to melt or plasticize and knead, and a foaming agent (2.5 parts by weight of HFO-1234ze, 100 parts by weight of base resin, isobutane) .0 parts by weight and 5.5 parts by weight of ethyl chloride were pressed into the resin near the tip of the first extruder.

  Thereafter, in a second extruder and a cooler coupled to the first extruder, the resin temperature is cooled to 108 ° C., and a 6 mm thick × 400 mm wide rectangular cross-section die provided at the tip of the cooler (slit die ) By extrusion foaming into the atmosphere at a foaming pressure of 5.0 MPa, and then a molding die placed in close contact with the die and a molding roll placed on the downstream side of the cross-sectional shape having a thickness of 60 mm × width 1000 mm An extruded foam plate was obtained and cut into a thickness of 50 mm × width 910 mm × length 1820 mm with a cutter. The evaluation results of the obtained foam are shown in Table 1.

(Examples 2 to 24)
As shown in Tables 1 and 2, extruded foams were obtained by the same operation as in Example 1 except that the types of the various compounds, the addition amounts, and / or the production conditions were changed. Physical properties of the resulting extruded foam are shown in Tables 1 and 2. Incidentally, as described above, the graphite was previously introduced in the form of a masterbatch of a styrene resin at the time of preparation of the resin mixture. When a masterbatch was used, the base resin was 100 parts by weight in total with the base resin contained in the masterbatch.

(Comparative Examples 1 to 21)
As shown in Table 3, an extruded foam was obtained by the same operation as in Example 1 except that the types of the various compounds, the addition amounts, and / or the production conditions were changed. Physical properties of the obtained extruded foam are shown in Table 3. Incidentally, as described above, the graphite was previously introduced in the form of a masterbatch of a styrene resin at the time of preparation of the resin mixture. When a masterbatch was used, the base resin was 100 parts by weight in total with the base resin contained in the masterbatch.

  As can be seen from Examples 1 to 24, the extruded styrenic resin foam according to the present invention is excellent in thermal conductivity, such as thermal conductivity of 0.0193 to 0.0243 W / mK, and excellent in flame retardancy, and further, It is clear that THF insoluble matter does not occur in the accelerated deterioration test and the continuous productivity is excellent.

  As can be seen from Comparative Examples 17 to 21, when only polystyrene is used as the styrenic resin, even if a high molecular weight brominated flame retardant is used, the molecular weight of the brominated flame retardant exceeds the range of the present invention. The THF insoluble matter does not occur in the accelerated deterioration test, and furthermore, a styrene resin extruded foam excellent in flame resistance can be obtained. However, as can be seen from Comparative Examples 1 to 11 and Comparative Examples 13 to 16, the styrene-based resin contains a styrene-acrylonitrile copolymer, and the molecular weight of the brominated flame retardant is high beyond the scope of the present invention. When a molecular type brominated flame retardant is used, the obtained styrenic resin extruded foam has THF insoluble matter in the deterioration acceleration test even if it contains a stabilizer equivalent to Comparative Examples 17 to 21. Furthermore, the JIS flammability deteriorates and the flame retardancy is deteriorated. As shown in Comparative Examples 1 to 4 and 13 to 15, as shown in Comparative Examples 4 to 6, even when the amount of the flame retardant is changed as shown in Comparative Examples 4 to 6, shown in Comparative Examples 4 and 7 to 8 As shown in Comparative Examples 4 and 9, even when the ratio of polystyrene and styrene-acrylonitrile copolymer in styrenic resin is changed as shown in Comparative Examples 4 and 9, Comparative Examples 4 and 10 to 11 also change the addition amount of the stabilizer. The problem can not be solved even when the type of styrene-acrylonitrile copolymer used is changed as shown in FIG.

  On the other hand, as can be seen from the comparison of Example 6 with Comparative Example 18, Example 7 with Comparative Example 19, Example 10 with Comparative Example 20, Example 11 with Comparative Example 21 and Example 20 with Comparative Example 17, As shown in the examples, the case of containing a styrene-acrylonitrile copolymer as a styrene-based resin has a lower thermal conductivity, and a styrene-based resin extruded foam excellent in heat insulation performance can be obtained.

  As can be seen from Example 11 and Comparative Example 12, when the amount of the brominated flame retardant is within the range of the present invention, excellent flame retardancy can be imparted to the styrene resin extruded foam. Further, as can be seen from the comparison between Example 20 and Comparative Example 16, by setting the content of the foaming agent within the range of the embodiment of the present invention, the styrene resin extrusion-foaming foam has a low thermal conductivity and excellent thermal insulation. Get the body.

  According to the present invention, a styrenic resin extruded foam having excellent heat insulation and flame retardancy can be easily obtained. The styrenic resin extruded foam can be suitably used as a heat insulating material of a house or a structure.

Claims (23)

A styrenic resin extruded foam comprising a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent is at least one selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms, hydrofluoroolefins, and hydrochlorofluoroolefins in a total amount of 0.30 mol per kg of the styrene resin extruded foam. Including
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
Styrenic resin extruded foam. It is a styrenic resin extruded foam containing styrenic resin containing a styrene-acrylonitrile copolymer and brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin,
The average cell diameter of the styrene resin extruded foam is 0.05 mm or more and less than 0.15 mm,
Styrenic resin extruded foam. A styrenic resin extruded foam comprising a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent comprises at least one selected from the group consisting of hydrofluoroolefins and hydrochlorofluoroolefins,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
Styrenic resin extruded foam.   The styrenic resin extruded foam according to claim 3, wherein the total content of the hydrofluoroolefin and / or the hydrochlorofluoroolefin is 0.30 mol or more per 1 kg of foam of the styrenic resin extruded foam.   The styrenic resin extruded foam according to any one of claims 1 to 4, wherein the brominated flame retardant is a brominated bisphenol flame retardant and / or a brominated isocyanurate flame retardant. The brominated flame retardant is (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, (B) tetrabromobisphenol A-bis (2,3-dibromopropyl) ether, and (C) at least one selected from the group consisting of tris (2,3-dibromopropyl) isocyanurate,
The styrene resin extruded foam according to any one of claims 1 to 5. As a foaming agent, it contains at least one selected from the group consisting of hydrofluoroolefins and hydrochlorofluoroolefins.
The styrene resin extruded foam according to claim 2.   The styrenic resin extruded foam according to claim 1, wherein the blowing agent further contains an alkyl chloride.   The water content as a foaming agent is less than 1.0 weight part (however, 0 weight part is included) with respect to 100 weight parts of the said styrene resin, However, it is described in any one of Claims 1-8. Styrenic resin extruded foam.   The styrene resin extruded foam according to any one of claims 1 to 9, wherein a content of the styrene-acrylonitrile copolymer is 10 wt% to 100 wt% in 100 wt% of the styrene resin.   The styrene resin extrusion according to any one of claims 1 to 10, wherein the styrene resin is 0 wt% to 90 wt% of polystyrene and 10 wt% to 100 wt% of a styrene-acrylonitrile copolymer. Foam.   The styrene resin according to any one of claims 1 to 11, wherein at least one of the brominated flame retardants is (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether. Extruded foam. The brominated flame retardants include (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and (B) tetrabromobisphenol A-bis (2,3-dibromopropyl) ether Or
(A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and (C) tris (2,3-dibromopropyl) isocyanurate
The styrene resin extruded foam according to any one of claims 1 to 12.   The brominated flame retardant comprises (A) tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether in an amount of 25 wt% to 75 wt% in 100 wt% of the brominated flame retardant as a whole. The styrenic resin extruded foam according to any one of items 1 to 13.   The content of the acrylonitrile component contained in the said styrene-acrylonitrile copolymer is 10 weight% or more and 45 weight% or less in 100 weight% of styrene- acrylonitrile copolymers to any one of Claims 1-14. The styrene resin extrusion foam as described in the above.   The styrene according to any one of claims 1 to 15, wherein the black-based particles of the heat ray radiation inhibitor are contained in an amount of 0.5 to 5.0 parts by weight with respect to 100 parts by weight of the styrene-based resin. Resin extruded foam.   The styrene resin extruded foam according to any one of claims 1 to 16, wherein the graphite is contained in an amount of 0.5 parts by weight or more and 5.0 parts by weight or less based on 100 parts by weight of the styrene resin.   The tetrahydrofuran-insoluble matter content when dissolved in tetrahydrofuran after heating a styrene resin extruded foam after heating at 170 ° C. for 10 minutes at 250 ° C. for 1 hour is 5% by weight or less. The styrenic resin extruded foam according to any one of the preceding claims. The styrene resin extruded foam according to any one of claims 1 to 18, wherein an apparent density of the styrene resin extruded foam is 20 kg / m ³ or more and 60 kg / m ³ or less.   The styrene resin extruded foam according to any one of claims 1 to 19, wherein a closed cell rate of the styrene resin extruded foam is 85% or more.   The styrene resin extruded foam according to any one of claims 1 or 3 to 20, wherein an average cell diameter of the styrene resin extruded foam is 0.05 mm or more and less than 0.15 mm.   The styrene resin extruded foam according to any one of claims 1 to 21, wherein a thickness of the styrene resin extruded foam is 10 mm or more and 150 mm or less. A method of extrusion-foaming a styrenic resin composition containing a styrenic resin containing a styrene-acrylonitrile copolymer, a foaming agent, and a brominated flame retardant to produce a styrenic resin extruded foam,
The content of the acrylonitrile component contained in the styrene-based resin is 5% by weight or more and 45% by weight or less in 100% by weight of the styrene-based resin,
The blowing agent contains at least one member selected from the group consisting of saturated hydrocarbons having 3 to 5 carbon atoms, hydrofluoroolefins, and hydrochlorofluoroolefins, and water is used per 100 parts by weight of the styrene resin From 0 parts by weight to less than 1.0 parts by weight,
The brominated flame retardant is a brominated flame retardant having a molecular weight of 2000 or less, and
1.0 parts by weight or more and 8.0 parts by weight or less based on 100 parts by weight of the styrene resin
A method for producing a styrenic resin extruded foam.