JP6128940B2 - Method for producing polystyrene resin extruded foam plate - Google Patents

Description

  The present invention relates to a method for producing a polystyrene-based resin extruded foam plate, and more specifically, is a polystyrene-based resin extruded foam plate having excellent flame retardancy and high heat insulation, and excellent recyclability, which is a wall of a building, The present invention relates to a method for producing a polystyrene-based resin extruded foam plate that is suitably used for heat insulating materials such as floors and roofs, tatami core materials, and the like and is mainly formed in a plate shape.

  Conventionally, an air conditioner is added to a polystyrene resin material, heated and kneaded by an extruder, and then a physical foaming agent is pressed into the extruder and further kneaded. A thick polystyrene-based resin extruded foam plate (hereinafter also referred to as an extruded foam plate or a foamed plate) by molding into a plate shape with a shaping device connected to the die outlet of the extruder. It has been known.

In order to use the extruded foam board as a heat insulating material for construction, for example, it is required to satisfy the flammability standard of an extruded polystyrene foam heat insulating board described in JIS A 9511 (2006R). For this purpose, a flame retardant is added to the extruded foam plate, and hexabromocyclododecane (hereinafter referred to as HBCD) has been widely used as the flame retardant. HBCD is an excellent flame retardant that is versatile and can provide a flame retardant effect with a relatively small amount of addition.
However, there is a movement of regulation by the Chemical Substances Control Law and REACH for HBCD, and it is required to develop a flame retardant substitute extrusion foam board manufacturing technology that does not use HBCD flame retardant assuming that it is designated as a regulated substance. ing.

  On the other hand, chlorofluorocarbons (hereinafter referred to as CFC) such as dichlorodifluoromethane have been widely used as the foaming agent in the method for producing the extruded foam plate, but the relevance to the problem of ozone hole expansion. CFCs that are suspected of being refrained from being used, hydrogen atom-containing fluorinated fluorinated hydrocarbons (hereinafter referred to as HCFC) having a low ozone depletion potential, and hydrogen atom-containing fluorinated hydrocarbons having an ozone depletion potential of 0 (zero) HFC) has been used instead of CFC. Furthermore, from the viewpoint of global warming, saturated hydrocarbons such as isobutane and isopentane having an ozone depletion coefficient of 0 (zero) and a small global warming coefficient have been used instead of HCFC and HFC.

  However, since saturated hydrocarbons such as butane are flammable, in order to give sufficient flame retardancy to polystyrene-based resin extruded foam plates, compared to the case of using nonflammable foaming agents such as HFC. Many flame retardants had to be added. When a large amount of a flame retardant is added, there is a new problem that stability of extrusion foaming is remarkably impaired or physical properties of the obtained foamed plate are impaired.

In the above situation, studies have been made on polystyrene resin extruded foam plates using an excellent flame retardant other than HBCD. For example, a styrene-brominated butadiene copolymer type represented by Patent Document 1 has been proposed.
However, this styrene-brominated butadiene copolymer type flame retardant is inferior in thermal stability and has a problem in generating black spots (black foreign matters).

In order to improve the thermal stability of such a styrene-brominated butadiene copolymer type flame retardant, a method in which the flame retardant contains an alkyl phosphite and / or an epoxy compound has also been proposed (for example, Patent Documents). 2).
However, since the method of Patent Document 2 uses a flame retardant obtained by simply dry blending a styrene-brominated butadiene copolymer and other additives with a mixer, the thermal stability is still insufficient, and the extrusion conditions In some cases, the generation of black spots during extrusion foaming could not be completely suppressed.

  In order to solve these problems, the present inventors previously proposed a method using a melt-kneaded product of a styrene-brominated butadiene copolymer and a heat stabilizer as a flame retardant (Patent Document 3). .

JP 2009-516019 A JP 2012-512942 A Japanese Patent Application No. 2013-054221

The method of using the melt-kneaded material of Patent Document 3 as a flame retardant has the advantage that the generation of black spots is suppressed and a foamed plate having a good color tone is obtained. According to this, problems remain in the dispersibility and kneadability of the flame retardant with respect to the polystyrene resin.
The present invention was made to solve these problems, and by improving the dispersibility and kneadability of the flame retardant in the polystyrene resin, the extrusion stability was improved, and the surface smoothness was excellent. It is another object of the present invention to provide an industrially advantageous method for producing a polystyrene resin foam plate, which can stably obtain a foam plate having high flame retardancy.

According to this invention, the manufacturing method of the polystyrene-type resin extrusion foam board shown below is provided.
<1>
A method for producing a polystyrene resin extruded foam board by extrusion foaming a foamable resin melt obtained by kneading a polystyrene resin composition and a physical foaming agent,
The polystyrene resin composition, a polystyrene resin (a), a styrene - brominated butadiene copolymer seen containing 30 wt% or more, and a flame retardant composition comprising a thermal stabilizer (b), a polystyrene resin And a polystyrene-based resin composition (c) containing 0.1 to 10% by weight of a styrene-brominated butadiene copolymer, and the blending amount of the flame retardant composition (b) is It is 1 to 20 parts by weight with respect to 100 parts by weight of the polystyrene resin (a), and the blending amount of the polystyrene resin composition (c) is 10 to 150 parts by weight with respect to 100 parts by weight of the polystyrene resin (a). And adding the flame retardant resin composition (b) as a masterbatch or a melt-kneaded product .
<2>
The polystyrene resin extruded foam plate according to <1>, wherein the blending ratio (c / b) of the polystyrene resin composition (c) to the flame retardant composition (b) is 2 to 50. Manufacturing method.
<3>
The polystyrene resin (a) has a melt viscosity (ηa) of 500 to 2500 Pa · s at 200 ° C. and a shear rate of 100 sec ⁻¹ , and the polystyrene resin composition (c) for the melt viscosity (ηa) The ratio of the melt viscosity (ηc) under the conditions of 200 ° C. and a shear rate of 100 sec ⁻¹ is 0.8 to 2, and the polystyrene-based resin extruded foam plate according to <1> or <2> Manufacturing method.
<4>
Any of <1> to <3>, wherein the polystyrene-based resin composition (c) is a melt-kneaded product containing a styrene-brominated butadiene copolymer, a heat stabilizer, and a polystyrene-based resin. A process for producing a polystyrene resin extruded foam according to claim 1.
< 5 >
The heat stabilizer is one or more heat stabilizers selected from bisphenol type epoxy compounds, novolak type epoxy compounds, hindered phenol compounds, hindered amine compounds and phosphite compounds. <1> to the manufacturing method of the polystyrene resin extrusion foamed board in any one of <4> .
< 6 >
The polystyrene resin composition (c) obtained by heating and melting polystyrene resin extruded foam waste containing polystyrene-brominated butadiene copolymer and / or a pulverized product of the foamed plate. The method for producing a polystyrene-based resin extruded foam plate according to any one of <1> to < 5 >, wherein
< 7 >
The method for producing a polystyrene-based resin extruded foam plate according to any one of <1> to < 6 >, wherein the polystyrene-based resin composition (c) is pelletized.

  In the present invention, a polystyrene resin (a), a flame retardant composition (b) containing 30% by weight or more of a styrene-brominated butadiene copolymer, a polystyrene resin as a base resin, and styrene-brominated And a polystyrene resin composition (c) containing 0.1 to 10% by weight of a butadiene copolymer, and the amount of the flame retardant composition (b) is 100 parts by weight of the polystyrene resin (a). 1 to 20 parts by weight with respect to the polystyrene-based resin composition (c), and the amount of the polystyrene-based resin composition (c) is 10 to 150 parts by weight with respect to 100 parts by weight of the polystyrene-based resin (a). Since the resin composition is extruded and foamed, the dispersibility and kneadability of the flame retardant composition (b) to the polystyrene resin (a) is improved, the extrusion stability is improved, and there is no surface irregularity and the foam has excellent appearance. The can be stably manufactured. Furthermore, since the flame retardant is uniformly and sufficiently dispersed by the polystyrene-based resin composition (c), an extruded foam board having improved flame retardancy can be obtained.

The method for producing a polystyrene resin extruded foam plate by extrusion foaming a foamable resin melt containing a polystyrene resin composition and a physical foaming agent according to the present invention is as follows. It is characterized by satisfying requirements (i) and (ii).
(I) A polystyrene resin (a), a flame retardant composition (b) containing 30% by weight or more of a styrene-brominated butadiene copolymer, a polystyrene resin as a base resin, and a styrene-brominated butadiene copolymer And a polystyrene resin composition (c) containing 0.1 to 10% by weight of a polymer.
(Ii) The blending amount of the flame retardant composition (b) is 1 to 20 parts by weight with respect to 100 parts by weight of the polystyrene resin (a), and the blending amount of the polystyrene resin composition (c) is a polystyrene resin ( a) 10 to 150 parts by weight per 100 parts by weight.

According to the study by the present inventors, this melt-kneaded product of styrene-brominated butadiene polymer has high viscosity and low fluidity, and has left a problem in kneadability with polystyrene resin as a base resin. . That is, when manufacturing for a long time so that industrial production is performed, it discovered that extrusion stability was lacking and an unevenness | corrugation might generate | occur | produce in a part of foam board.
Therefore, as a result of further investigation, a polystyrene resin composition containing a styrene-brominated butadiene copolymer in a low concentration in a system in which the polystyrene resin (a) and the flame retardant composition (b) coexist ( When c) is blended, the polystyrene-based resin composition (c) unexpectedly functions as a compatibilizer, and the dispersibility and kneadability of the flame retardant composition (b) with respect to the polystyrene-based resin (a) are dramatically increased. The desired homogenous melt-kneaded product in which the three parties are integrated is obtained, and has excellent surface smoothness without unevenness and good color tone even when extruded and foamed continuously for a long time. It has been found that an extruded foam board can be produced stably. Furthermore, the polystyrene-based resin composition (c) containing the styrene-brominated butadiene copolymer at a low concentration exhibits a function as a compatibilizing agent, but at the same time, the flame retardant is uniform and sufficient. Since it was dispersed, it was found that an extruded foam plate with improved flame retardancy was obtained. The present invention has been made based on these findings.

  Hereinafter, the polystyrene resin composition used in the method for producing a polystyrene resin extruded foam plate of the present invention will be described.

(Essential component of polystyrene resin composition)
The polystyrene resin composition comprises at least a polystyrene resin (a), a flame retardant composition (b) containing 30% by weight or more of a styrene-brominated butadiene copolymer, a polystyrene resin as a base resin, and And a polystyrene resin composition (c) containing 0.1 to 10% by weight of a styrene-brominated butadiene copolymer.

(Polystyrene resin (a))
Examples of the polystyrene resin (a) include styrene-acrylic acid copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer having polystyrene or styrene as a main component. Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-maleic anhydride copolymer, styrene-polyphenylene ether copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer Examples thereof include a polymer, a styrene-methylstyrene copolymer, a styrene-dimethylstyrene copolymer, a styrene-ethylstyrene copolymer, and a styrene-diethylstyrene copolymer. The styrene unit component content in the styrenic copolymer is preferably 50 mol% or more, particularly preferably 80 mol% or more.

  As said polystyrene-type resin, what mixed the other polymer may be sufficient in the range in which the objective of this invention and an effect are achieved. Other polymers include polyester resins and polyethylene resins (one or a mixture of two or more selected from the group consisting of ethylene homopolymers and ethylene copolymers having an ethylene unit component content of 50 mol% or more). , Polypropylene resins (one or a mixture of two or more selected from the group of propylene homopolymers and propylene copolymers having a propylene unit component content of 50 mol% or more), polyphenylene ether resins, styrene-butadiene- Styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer hydrogenated product, styrene-isoprene-styrene block copolymer hydrogenated product, styrene-ethylene copolymer, etc. These other polymers are listed in polystyrene resins. As it will be less than an amount%, preferably such that 30 wt% or less, more preferably such that 10 wt% or less, can be mixed according to the purpose.

Moreover, as said polystyrene-type resin, it is preferable to use the thing whose melt viscosity (200 degreeC and the conditions of a shear rate of 100 sec- ¹ ) is about 500-2500 Pa.s from a foamable or moldable viewpoint, Preferably it is 600-2000 Pa.s, More preferably, it is 700-1500 Pa.s.

(Flame retardant composition containing 30% by weight or more of styrene-brominated butadiene copolymer (b))
The flame retardant composition (b) contains at least 30% by weight or more of a styrene-brominated butadiene block copolymer.
The concentration of the styrene-brominated butadiene copolymer is desirably 50% by weight or more, more preferably 60% or more, and even more preferably 70% by weight or more. When the amount of the styrene-brominated butadiene polymer is too small, the effect of the heat stabilizer on the flame retardant is liable to be impaired. desirable.
Such a flame retardant composition (b) includes a flame retardant and a thermal stabilizer that contain a styrene-brominated butadiene copolymer so that the concentration of the styrene-brominated butadiene copolymer is 30% by weight or more. The flame retardant aid, plasticizer, polystyrene resin and the like are prepared according to the above.
The flame retardant composition (b) is preferably a melt-kneaded product obtained by melt-kneading in an extruder. From the viewpoint of meterability, ease of handling, etc., the flame-retardant composition (b) is cut after being extruded into a strand form from the extruder. Thus, it is preferably pelletized.

In addition, it is preferable that the melt viscosity of the flame retardant composition (b) is generally 1000 to 3000 Pa · s at 200 ° C. and 100 sec ⁻¹ .

(Styrene-brominated butadiene copolymer)
The styrene-brominated butadiene copolymer itself contained in the flame retardant composition (b) and functioning as a brominated flame retardant is a conventionally known one. For example, those disclosed in Patent Documents 1 and 2 are used as they are. Can be used.

Generally, the styrene-brominated butadiene copolymer used as a flame retardant is approximately 1.0 × 10 ^{3 to} 2.0 × 10 ⁵ , preferably 2.0 × 10 ³ to 1 in terms of polybutadiene. By brominating a butadiene copolymer of 0.0 × 10 ⁵ , more preferably 5.0 × 10 ^{3 to} 1.0 × 10 ⁵ , and even more preferably 5.0 × 10 ^{4 to} 1.0 × 10 ⁵ Manufactured.

When a styrene-brominated butadiene copolymer is used as a flame retardant for a polystyrene resin, considering compatibility with the polystyrene resin, the styrene-brominated butadiene copolymer is a block containing a styrene monomer component unit. It is preferably a copolymer, a random copolymer or a graft copolymer, and more preferably a block copolymer of a polystyrene polymer block and a brominated polybutadiene block.
Examples of styrene monomers include styrene, brominated styrene, chlorinated styrene, 2-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, α-methylstyrene, and the like. , Styrene, 4-methylstyrene, α-methylstyrene, or a mixture thereof, more preferably styrene.

  From the viewpoint of imparting flame retardancy, the bromine content in the styrene-brominated butadiene copolymer is preferably 60% by weight or more, and more preferably 63% by weight or more. The bromine content can be determined based on JIS K7392: 2009.

Considering dispersibility in polystyrene resin and the like, the weight average molecular weight of the styrene-brominated butadiene copolymer is preferably about 1.0 × 10 ^{5 to} 2.0 × 10 ^{5 in} terms of polystyrene, The melt viscosity at 200 ° C. and 100 sec ⁻¹ is about 4000 to 8000 Pa · s.

  In general, a polystyrene-brominated polybutadiene block copolymer which is a typical styrene-brominated butadiene copolymer can be represented by the following general formula.

（式中、Ｘ、Ｙ及びＺは、正の整数である。）

(In the formula, X, Y and Z are positive integers.)

Such a polystyrene-brominated polybutadiene block copolymer is produced, for example, by brominating a polystyrene-polybutadiene block copolymer.
Examples of the polystyrene-brominated polybutadiene copolymer preferably used in the present invention include commercially available products such as Emerald 3000 from Chemtura and FR122P from ICL-IP.

  The styrene-brominated butadiene copolymer exhibits excellent flame retardancy when used as a flame retardant for thermoplastic resins such as polystyrene. However, since the styrene-brominated butadiene polymer is inferior in thermal stability in the molten state, bromine tends to be liberated from the polymer depending on the melt processing conditions, and the release of bromine may reduce the flame retardancy imparting effect. There is a risk of decomposing the thermoplastic resin. Furthermore, since the styrene-brominated butadiene copolymer is a polymer, if the carbon-carbon unsaturated bond is formed in the polymer by liberation of bromine, the polymer itself or the thermoplastic resin may be colored. In addition, there are various problems that the styrene-brominated butadiene copolymer may gel due to the crosslinking of the unsaturated bond, or that the polymer itself or the thermoplastic resin may generate black spots.

  In general, in order to suppress the liberation of bromine during melt processing, a method of blending a heat stabilizer can be considered, but simply by blending a heat stabilizer into a styrene-brominated butadiene polymer by a dry blend method, The occurrence of discoloration and black spots could not be sufficiently suppressed.

  In order to solve such problems, the present inventors changed the styrene-brominated butadiene copolymer and the thermal stabilizer into a styrene-brominated butadiene copolymer instead of the dry blend method during the production of the extruded foam plate. The method of mix | blending a heat stabilizer and melt-kneading these as a flame retardant melt-kneaded material to the base resin of an extrusion foaming board was proposed previously (patent document 3). According to this method, generation | occurrence | production of a black spot and discoloration of an extrusion foaming board can be suppressed effectively.

(Heat stabilizer)
Therefore, when manufacturing the said flame retardant composition (b), it is preferable to add a heat stabilizer. The heat stabilizer of the styrene-brominated butadiene copolymer is one or more selected from bisphenol type epoxy compounds, novolac type epoxy compounds, hindered phenol compounds, hindered amine compounds and phosphite compounds. A heat stabilizer is mentioned. In addition, it is preferable that the compounding quantity of the said heat stabilizer is 5-40 weight part with respect to 100 weight part of styrene-brominated butadiene copolymers.

  Examples of the bisphenol type epoxy compound and the novolak type epoxy compound include F2200HM manufactured by ICL-IP, EPICLON series manufactured by DIC, Araldite ECN1280 manufactured by HUNTUMAN, and the like.

Examples of the hindered phenol compound include 2,6-di-t-butyl-p-cresol, triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], Tetrakis- [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propinate] methane, 2,2-methylenebis (4-methyl-6-tert-butylphenol), 1,6-hexanediol -Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and the like.
You may use these individually or in combination of 2 or more types. Among these, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] is preferable from the viewpoint of extrusion stability and flame retardancy.

Examples of the hindered amine compound include 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-hydroxy-1,2,2,6,6-pentamethylpiperidine, or 4-hydroxy-1- Octyloxy-2,2,6,6-tetramethylpiperidine aliphatic or aromatic carboxylic acid ester, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) -2- (3,5- Di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate, bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidinyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, tetrakis (2,2,6,6-tetramethyl-4 Piperidinyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) -1,2,3,4-butanetetracarboxylate and the like. It is done.
You may use these individually or in combination of 2 or more types. Among these, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, or bis (from the point of extrusion stability and flame retardancy) 2,2,6,6-tetramethyl-4-piperidinyl) sebacate is preferred.

  Examples of the phosphite compound include tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and bis (2,6 -Di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite, distearyl pentaerythritol diphosphite, tetra (tridecyl) -4,4'-butylidene-bis (2-t-butyl-5-methylphenyl) Diphosphite, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, bis (nonylphenyl) pentaerythritol diphosphite, mono (dinonylphenyl) mono-p- Nonylphenyl phosphite, tris (monononylphenyl) phosphite, tetraalkyl (C = 12-16) -4,4′-isopropylidene- (bisphenyl) diphosphite, hexatridecyl-1,1,3-tris (3-tert-butyl-6-methyl-4oxyphenyl) -3 -Methylpropane triphosphite, diphenylisodecyl phosphite, tridecyl phosphite, tristearyl phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer and the like. You may use these individually or in combination of 2 or more types. Among these, from the viewpoint of extrusion stability, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite or bis (2,6-di-t-butyl-4-methylphenyl) penta Erythritol diphosphite is preferred.

  In addition, as said heat stabilizer, it is preferable to use together the compound selected from a bisphenol-type epoxy compound and / or a novolak-type epoxy compound, and a hindered phenol type compound, a hindered amine type compound, and a phosphite type compound. In the above case, the total amount of the bisphenol type epoxy compound and / or the novolak type epoxy compound is preferably 5 to 20 parts by weight with respect to 100 parts by weight of the styrene-brominated butadiene copolymer. On the other hand, the total amount of the compound selected from the hindered phenolic compound, the hindered amine compound, and the phosphite compound is 0.2 to 20 parts by weight with respect to 100 parts by weight of the styrene-brominated butadiene copolymer. Preferably there is.

In the present invention, the use of the flame retardant composition (b) generally eliminates the thermal stability of the flame retardant, but the flame retardant composition contains a high styrene-brominated butadiene copolymer. Included in concentration.
As an aspect of adding the flame retardant resin composition (b) to the polystyrene resin (a), a method of directly adding a styrene-brominated butadiene copolymer, a method of adding as a masterbatch, or an addition as a melt kneaded product However, since the styrene-brominated butadiene copolymer has a very high viscosity relative to the polystyrene resin, the flame retardant composition for the polystyrene resin (a) is used in any method. The dispersibility and kneadability of (b) become insufficient, and thus the extrusion stability may be reduced. This decrease in extrusion stability appears particularly when a thick foam plate is obtained.
In order to eliminate such problems and improve the dispersibility and the extrusion stability, in the present invention, as described above, a polystyrene resin is used as a base resin, and a styrene-brominated butadiene copolymer is added to a styrene copolymer. A polystyrene resin composition (c) containing 1 to 10% by weight is used.

(Polystyrene resin composition (c))
That is, in the present invention, a polystyrene resin composition (c) containing a polystyrene resin as a base resin and 0.1 to 10% by weight of a styrene-brominated butadiene copolymer is used as the polystyrene resin (a). And mixed with the flame retardant composition (b).
The polystyrene resin composition (c) acts as a compatibilizer between the polystyrene resin (a) and the flame retardant composition (b), and the polystyrene resin (a) and the flame retardant composition (b). As a result, the stability of extrusion is improved, and even thick foamed plates such as extruded foam insulation plates are used for production. A plate can be obtained stably.

  The concentration of the styrene-brominated butadiene block copolymer in the polystyrene resin composition (c) is preferably 0.1 to 10% by weight. If the concentration is too low, the effect of improving the extrusion stability cannot be obtained. On the other hand, if the concentration is too high, the dispersibility of the flame retardant may be reduced. From the said viewpoint, More preferably, it is 0.2 to 8 weight%, More preferably, it is 0.5 to 5 weight%.

As the polystyrene resin composition (c) containing a polystyrene resin as a base resin and 0.1 to 10% by weight of a styrene-brominated butadiene block copolymer, a styrene-brominated butadiene copolymer and a polystyrene resin are used. In the melt-kneaded product, the styrene-brominated butadiene block copolymer, which is a flame retardant, is melt-kneaded at least once in an extruder or the like. From the above, it is preferable because it is more uniformly dispersed in the polystyrene resin.
Furthermore, it is preferable to add a heat stabilizer when melt-kneading in advance. Such a melt-kneaded product exists as a stable polystyrene-based resin composition in which black spots and yellowing are suppressed, and its compatibilizing function is effectively exhibited. From the above viewpoint, it is preferable to prepare the polystyrene resin composition (c) by melt-kneading the flame retardant composition (b) and the polystyrene resin.

  The polystyrene resin composition (c) is a melt kneaded product of a styrene-brominated butadiene copolymer and a polystyrene resin that does not use a regenerated raw material (a polystyrene resin melt kneaded product that does not use a regenerated raw material). The polystyrene-based extruded foam plate containing a styrene-brominated butadiene copolymer, and / or a crushed product of the foamed plate, ie, a styrene-brominated butadiene copolymer. It is possible to use a material obtained by cutting and pulverizing mill ends, scraps, and / or polystyrene-based extruded foam plates containing a styrene-brominated butadiene copolymer. In particular, it is preferable to use a polystyrene-based resin composition (regenerated polystyrene-based resin composition) obtained by melting and regenerating a polystyrene-based resin extruded foamed board scrap containing a styrene-brominated butadiene copolymer and / or a pulverized product of the foamed board. . By using this regenerated polystyrene resin composition, there is also an advantage that it can be a manufacturing method considering the environment from the viewpoint of recycling.

Moreover, when using this regenerated polystyrene resin composition, the polystyrene resin and the styrene-brominated butadiene block copolymer, which are constituent components, are melt-kneaded in an extruder at least three times ( First: Melt kneading in the manufacturing process of the first foamed board (foamed board not containing recycled raw material) Second time: Melting and kneading in the manufacturing process of the recycled PS resin composition itself Third time: Second foaming A melt-kneaded product of a styrene-brominated butadiene copolymer and a polystyrene-based resin (the virgin polystyrene system without using a regenerated raw material) Compared to the resin melt kneaded product), the styrene-brominated butadiene block copolymer is further uniformly kneaded, and the compatibilizing function and the flame retarding function are improved.
The polystyrene-based resin composition (c) is preferably cut and pelletized after being extruded into a strand form from an extruder from the standpoint of meterability and ease of handling.

(Mixing ratio of essential constituents of polystyrene resin composition)
The polystyrene resin (a), the flame retardant fat composition (b), and the polystyrene resin composition (c) are desirably mixed in the following composition.
The blending amount of the flame retardant composition (b) is 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polystyrene resin (a). Part.
When the blending amount of the flame retardant composition (b) is too large, the viscosity of (b) itself is high. On the other hand, when there are too few compounding quantities of this flame retardant composition (b), there exists a possibility that it may become inadequate to obtain the flame retardance desired.
Further, the blending amount of the polystyrene resin composition (c) is 10 to 150 parts by weight, preferably 15 to 130 parts by weight, more preferably 20 to 110 parts by weight with respect to 100 parts by weight of the polystyrene resin (a). Part.
If the resin composition having a low concentration is too much, the extrusion stability may be lowered. On the other hand, when the amount is too small, the dispersibility of the flame retardant and the stability during extrusion are impaired.

  The blending ratio (c / b) between (c) and (b) is preferably 2 to 50, more preferably 3 to 40, from the viewpoint of kneadability between the polystyrene resin and the flame retardant composition. .

Moreover, it is preferable that the weight average molecular weights of the said polystyrene-type resin (a) are 200,000-450,000. Furthermore, it is preferable that the weight average molecular weights of the said polystyrene-type resin composition (c) are 200,000-400,000.
The weight average molecular weight used in the present invention is a value obtained by dissolving 10 mg of a sample in 10 ml of tetrahydrofuran (THF), measuring by gel permeation chromatography (GPC) analysis, and calibrating with standard polystyrene.
When the weight average molecular weight is within the above range, the kneadability of the resin composition becomes better, and the extruded foam plate has excellent strength.
Furthermore, the ratio (Mwc / Mwa) of the weight average molecular weight (Mwc) of the polystyrene resin composition (c) to the weight average molecular weight (Mwa) of the polystyrene resin (a) is 0.5 to 1.1. Is preferable, and 0.7 to 1 is more preferable. In particular, when a styrene-brominated butadiene copolymer is used as a flame retardant, it is possible to obtain a polystyrene resin composition (c) having a high molecular weight because thermal degradation of the polystyrene resin is suppressed. Become.

  Moreover, it is preferable that the melt viscosity of the said polystyrene-type resin composition (c) is 500-2500 Pa.s. If melt viscosity is in the said range, the kneadability of a resin composition will become more favorable. Furthermore, the ratio (ηc / ηa) of the melt viscosity (ηc) of the polystyrene resin composition (c) to the melt viscosity (ηa) of the polystyrene resin (a) is preferably 0.8-2. It is more preferable that it is 0.9-1.5 from the viewpoint of the kneadability of the foamable resin melt.

  In the present invention, other flame retardants can be used by mixing with the flame retardant of the styrene-brominated butadiene copolymer as long as the objects and effects of the present invention are not hindered. Other flame retardants include, for example, tetrabromobisphenol-A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol-S-bis (2,3-dibromo-2-methylpropyl ether), An organic compound having a 2,3-dibromo-2-methylpropyl group represented by tetrabromobisphenol-F-bis (2,3-dibromo-2-methylpropyl ether)), tetrabromobisphenol-A-bis (2 , 3-dibromopropyl ether), tetrabromobisphenol-S-bis (2,3-dibromopropyl ether), tetrabromobisphenol-F-bis (2,3-dibromopropyl ether), tris (2,3-dibromopropyl) ) Isocyanurate and tris (2,3-dibromopropyl) Organic compounds having a 2,3-dibromopropyl group typified by annulate, mono (2,3,4-tribromobutyl) isocyanurate, di (2,3,4-tribromobutyl) isocyanurate, tris (2 , 3,4-Tribromobutyl) isocyanurate, brominated isocyanurate, cresyl di 2,6-xylenyl phosphate, antimony trioxide, antimony pentoxide, ammonium sulfate, zinc stannate, cyanuric acid, pentabromo Typical examples include nitrogen-containing cyclic compounds such as toluene, isocyanuric acid, triallyl isocyanurate, melamine cyanurate, melamine, melam, melem, silicone compounds, inorganic compounds such as boron oxide, zinc borate, zinc sulfide, and triphenyl phosphate. Phosphoric ester, red phosphorus, polyphosphorus Ammonium, phosphazene, phosphorus-based compounds such as hypophosphorous acid salts and the like. These compounds can be used alone or in admixture of two or more.

In this invention, the improvement effect of an oxygen index can further be heightened by mix | blending at least 1 sort (s) of agent chosen from a diphenylalkane, diphenylalkene, and polyalkylbenzene with a flame retardant in an extrusion foaming board. The additive is preferably added in an amount of 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the flame retardant.
Specific examples of the diphenylenyl alkane include 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, and 3,4-dimethyl-3,4-diphenylhexane. 3,4-diethyl-3,4-diphenylhexane. Specific examples of diphenylalkene include 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, and polyalkylenebenzene. , 4-diisopropylbenzene.

In the present invention, an antioxidant can be added. The above-mentioned antioxidant is composed mainly of one or more antioxidants selected from phenolic compounds, hindered amine compounds and phosphorus compounds, but if necessary, other stabilizers are used in combination. You can also
Examples of such stabilizers include metal soaps, organotin compounds, lead compounds, hydrotalcite, polyhydric alcohols, β-ketones, and sulfur compounds.

  In the production method of the present invention, in addition to the flame retardant, a foam regulator can be added to the foamable molten resin composition in order to adjust the average cell diameter of the extruded foam plate. Examples of the air conditioner include inorganic substances such as talc, kaolin, mica, silica, calcium carbonate, barium sulfate, titanium oxide, clay, aluminum oxide, bentonite, and diatomaceous earth. Further, in the present invention, two or more kinds of the air bubble adjusting agents can be used in combination. Among the various bubble regulators, talc is preferably used because it is easy to adjust the bubble diameter of the foamed plate obtained and to easily reduce the bubble diameter. Talc having a 50% particle size (permeation centrifugal sedimentation method) of 0.5 to 75 μm is preferred.

  The amount of the air bubble regulator added is preferably 0.01 to 5 parts by weight and more preferably 0.1 to 4 parts by weight with respect to 100 parts by weight of the polystyrene resin (a).

  In the production method of the present invention, in addition to the above-mentioned bubble regulator and flame retardant, a heat insulation improver such as graphite, hydrotalcite, carbon black and aluminum, and a colorant, as long as the object and effect of the present invention are not hindered. Various additives such as fillers and lubricants can be appropriately added. In addition, you may add various additives, such as the said bubble regulator, as a masterbatch which uses thermoplastic resins, such as a polystyrene-type resin, as a base material.

(Foaming agent)
In the foaming agent used in the present invention, the saturated hydrocarbon (X) having 3 to 5 carbon atoms and the other foaming agent (Y) shown below can be used alone or in combination, and particularly described in the background art. From the viewpoint, it is more preferable to use a mixed foaming agent containing a saturated hydrocarbon (X) having 3 to 5 carbon atoms and another foaming agent (Y) shown below.

Examples of the saturated hydrocarbon (X) having 3 to 5 carbon atoms include propane, n-butane, i-butane, n-pentane, i-pentane, neopentane and the like.
Said saturated hydrocarbon (X) can be used individually or in mixture of 2 or more types.
Among the saturated hydrocarbons (X), propane, n-butane, i-butane or a mixture thereof is preferable from the viewpoint of foamability. Moreover, n-butane, i-butane or a mixture thereof is preferable from the viewpoint of the heat insulating performance of the foamed plate, and i-butane is particularly preferable.

As another foaming agent (Y), an organic physical foaming agent and an inorganic physical foaming agent can be used.
Examples of the organic physical foaming agent include ethers such as dimethyl ether, diethyl ether, ethyl methyl ether, di-n-butyl ether, diisopropyl ether, methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i- Examples include alcohols such as butyl alcohol and t-butyl alcohol, formic acid esters such as methyl formate, ethyl formate, propyl formate, and butyl formate, and alkyl chlorides such as methyl chloride and ethyl chloride. In addition, trans-1,3,3,3-tetrafluoropropene, cis-1,3,3,3-tetrafluoropropene, 1,1,1,2 having a low ozone depletion coefficient and a low global warming potential Fluorinated unsaturated hydrocarbons such as tetrafluoropropene can also be used.
Examples of the inorganic physical foaming agent include water, carbon dioxide, nitrogen and the like.
Said other foaming agent (Y) can be used individually or in mixture of 2 or more types.

  Among the other foaming agents (Y), methyl chloride, ethyl chloride, dimethyl ether, diethyl ether, ethyl methyl ether, methanol, ethanol, water, and carbon dioxide are preferable from the viewpoints of foamability and foam plate moldability. .

  In the mixed foaming agent, the blending ratio of the saturated hydrocarbon (X) is 10 to 80 mol%, and the blending ratio of the other foaming agent (Y) is 90 to 20 mol% [however, the foaming agent (X) and The total amount with the foaming agent (Y) is preferably 100 mol%]. By using a mixed foaming agent with a blending ratio within this range, it becomes possible to produce an extruded foam plate having a high expansion ratio safely and stably, and an extruded foam plate excellent in heat insulation and flame retardancy. Is preferable in manufacturing. From this viewpoint, saturated hydrocarbon (X) 30 to 70 mol% and other blowing agent (Y) 70 to 30 mol% [however, the total amount of blowing agent (X) and blowing agent (Y) is 100 mol%. And a mixed foaming agent containing

  The addition amount of the foaming agent in the present invention is preferably added so as to be 0.5 to 2.5 mol / kg in 1 kg of the polystyrene resin composition, and 0.8 to 2.0 mol / kg is preferable. More preferred.

The apparent density of the polystyrene resin extruded foam plate obtained by the present invention is 20 to 60 kg / m ³ , preferably 22 to 50 kg / m ³ .

  The lower limit of the thickness of the polystyrene-based resin extruded foam plate is preferably 10 mm, more preferably 20 mm, and even more preferably 40 mm. In particular, when the thickness of the foamed plate is increased, the extrusion stability tends to be lowered, and the production method of the present invention is useful. Moreover, the upper limit is preferably 150 mm, more preferably 140 mm, and still more preferably 130 mm. Specifically, the width of the extruded foam plate is preferably 500 mm to 1500 mm.

  Further, the average cell diameter in the thickness direction is preferably 0.75 mm or less, more preferably 0.5 mm or less, and further preferably 0.3 mm or less in order to obtain a foamed plate having higher heat insulation.

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

  In order to obtain the extruded foam plates of Examples and Comparative Examples, the following apparatuses and materials were used.

[Extruding equipment]
A first extruder having an inner diameter of 65 mm and a second extruder having an inner diameter of 90 mm are connected in series, a physical foaming agent injection port is provided near the end of the first extruder, and a resin discharge having a rectangular cross section with a gap of 1 mm and a width of 110 mm is provided. A production apparatus in which a flat die provided with an outlet (die lip) was connected to the outlet of the second extruder was used.
At the resin outlet of the second extruder, a shaping device (guider) constituted by a plate made of a pair of upper and lower polytetrafluoroethylene resins installed so as to be parallel thereto was attached.

[material]
(Polystyrene resin (a))
PS1 (polystyrene): weight average molecular weight 27 × 10 ⁴ , melt viscosity 950 Pa · S (200 ° C., shear rate 100 sec ⁻¹ )

(Flame retardant composition (b))
A flame retardant (styrene-brominated butadiene copolymer, manufactured by Chemtura, Emerald 3000) and a thermal stabilizer (EPICLON N680, Irganox 1010, PEP36) shown in Table 1 were twin-screw extruder (inner diameter 20 mm, L / D = 48). Is used to adjust the temperature so that the resin temperature is 175 ° C., melt kneaded, extruded into a strand at a discharge rate of 10 kg / hr, and cut into a pellet to obtain a high-concentration flame retardant composition shown in Table 1 (B) was obtained.

(Polystyrene resin composition (c1))
Using an extruder with an inner diameter of φ50, the raw materials shown in Table 2 were introduced into the extruder, melted and kneaded at a resin temperature of 165 ° C., and then extruded at a discharge rate of 15 kg / hour to obtain a pellet-like low concentration resin composition (b1) Obtained. In addition, the flame retardant and the heat stabilizer were added so that the flame retardant composition (b) was blended as shown in Table 2. Therefore, the (c1) contains 3.5% by weight of a styrene-brominated butadiene copolymer.

(Polystyrene resin composition (c2))
A first extruder having an inner diameter of 65 mm and a second extruder having an inner diameter of 90 mm are connected in series, a physical foaming agent injection port is provided near the end of the first extruder, and a resin discharge having a rectangular cross section with a gap of 1 mm and a width of 110 mm is provided. A production apparatus in which a flat die provided with an outlet (die lip) was connected to the outlet of the second extruder was used. Moreover, what attached the shaping apparatus (guider) comprised by the board which consists of a pair of upper and lower polytetrafluoroethylene resin installed so that it might be parallel to this at the resin exit of the 2nd extruder was used.
A polystyrene resin virgin raw material (a), a styrene-brominated butadiene copolymer, and a cell regulator are heated to 200 ° C. in a first extruder and melt-kneaded, and are provided in the vicinity of the tip of the first extruder. The required amount of the physical foaming agent having the composition shown in Table 3 was supplied from the foaming agent inlet. Then, the foamable molten resin composition further melted and kneaded in the first extruder is supplied to the subsequent second extruder, and the resin temperature is expressed as a foaming suitability temperature as shown in Table 3 (the foaming temperature is indicated in the table). The foaming temperature was adjusted to be the temperature of the foamable molten resin composition measured at the position of the junction between the extruder and the die), and was then disposed in parallel at a gap of 25 mm from the die lip at a discharge rate of 70 kg / hr. It was extruded into a guider and passed through the guider while being foamed to form (shape) a plate to produce a polystyrene resin extruded foam plate. In addition, a styrene-brominated butadiene copolymer is added so that the flame retardant composition (b) has a blending ratio shown in Table 3, and a bubble regulator is added so that talc has a blending amount shown in Table 3. did.
After the extruded foam plate is pulverized, it is supplied to a single-screw extruder having an inner diameter of 90 mm and L / D = 50, kneaded at a maximum temperature of 220 ° C., and the molten resin is extruded in a strand shape at a discharge rate of 250 kg / hr, and pellets By cutting into a shape, pellets of polystyrene resin composition (c2) (recycled polystyrene resin composition) were obtained. Therefore, (c2) contains 3.5% by weight of a styrene-brominated butadiene copolymer.

(Bubble preparation agent)
Talc (Matsumura Sangyo, high filler # 12)
(Flame retardants)
Emerald 3000: Styrene-brominated butadiene block copolymer (manufactured by Chemtura) (melt viscosity 5300 Pa · S (200 ° C., shear rate 100 sec ⁻¹ ))
(Heat stabilizer)
EPICLON N680 (manufactured by DIC): novolac type epoxy resin Irganox 1010 (manufactured by BASF): pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]
PEP36 (manufactured by ADEKA): bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite

Example 1
The virgin polystyrene resin (a; PS1) and the flame retardant composition described above so as to have the blending amounts shown in Table 4 in the first extruder in the same manner as the polystyrene resin composition (c2). (B), a polystyrene-based resin composition (c1), and a bubble regulator (talc) are supplied, heated to 200 ° C. in the first extruder, melted and kneaded, and provided near the tip of the first extruder. A required amount of the physical foaming agent having the composition shown in Table 4 was supplied from the obtained physical foaming agent inlet. In addition, the bubble regulator was added so that talc might become the compounding quantity of Table 4.

  Subsequently, the foamable molten resin composition further melt-kneaded in the first extruder is supplied to the subsequent second extruder, and the resin temperature is expressed as a foaming suitable temperature as shown in the table (the foaming temperature is indicated in the table). The foaming temperature was adjusted to the temperature of the foamable molten resin composition measured at the position of the joint between the extruder and the die), and was then disposed in parallel at a discharge rate of 70 kg / hr and a gap of 50 mm from the die lip. It was extruded into a guider and passed through the guider while being foamed to form (shape) a plate to produce a polystyrene resin extruded foam plate.

(Example 2)
In Example 1, a polystyrene resin extruded foam plate was obtained in the same manner as in Example 1 except that the blending amount of the polystyrene resin composition (c1) was changed to the values shown in Table 4.

(Example 3)
In Example 1, a polystyrene resin extruded foam plate was obtained in the same manner as in Example 1 except that the blending amount of the polystyrene resin composition (c1) was changed to the values shown in Table 4.

Example 4
In Example 3, a polystyrene resin extruded foam plate was prepared in the same manner as in Example 3 except that the polystyrene resin fat composition (c1) was replaced with a polystyrene resin fat composition (c2) (recycled polystyrene resin composition). Obtained. The ratio (MWc / Mwa) of the weight average molecular weight (Mwa) of the polystyrene resin (a) and the weight average molecular weight (Mwc) of the polystyrene resin composition (c) is 1.0, and the melt viscosity ratio (Ηc / ηa) was 1.

Comparative Example 1
A polystyrene resin extruded foam plate was obtained in the same manner as in Example 1 except that the polystyrene resin composition (c1) was not added.

  Extrusion stability in the methods of Examples 1 to 4 and Comparative Example 1, and apparent density, thickness, closed cell ratio, appearance, color tone, bubble diameter, thermal conductivity, combustion of the obtained polystyrene resin extruded foam plate Properties and molecular weights are shown in Table 4.

The measurement method and evaluation method of various physical properties of the extruded foam plate shown in Table 4 are as follows.

(Extrusion stability)
A: An extruded foam board having no surface irregularities and good appearance can be obtained stably for a long time.
(Triangle | delta): When it drive | operates for a long time, discharge pressure will fluctuate and it will become an extrusion foam board in which surface unevenness was formed in a part.
×: Product cannot be obtained

(Apparent density)
It is an apparent density measured based on JIS K7222 (2005).

(thickness)
In the vicinity of the central portion in the width direction of the extruded foam plate, the thicknesses of five points were measured at equal intervals, and the arithmetic average value of these measured values was taken as the thickness (mm) of the extruded foam plate.

(Closed cell rate)
The closed cell ratio of the extruded foam plate was determined as follows. First, the extrusion foamed board was divided into 5 equal parts in the width direction, and cut samples (total 5 pieces) having no molded skin were cut out in the size of 25 mm × 25 mm × 20 mm from the vicinity of the center. Next, according to the procedure C of ASTM-D2856-70, the true volume Vx of each cut sample is measured, the closed cell ratio S (%) is calculated by the following formula (1), and the arithmetic average value of these calculated values is calculated. The closed cell ratio of the extruded foam plate was used. In addition, Toshiba Beckman Co., Ltd. air comparison type hydrometer 930 type was used as a measuring apparatus.

S (%) = (Vx−W / ρ) × 100 / (Va−W / ρ) (1)
However, Vx: the true volume (cm ³ ) of the cut sample obtained by measurement with the above air comparison hydrometer (the volume of the resin composition constituting the cut sample of the extruded foam plate and the closed cell portion in the cut sample (This corresponds to the sum of the total volume of bubbles.)
Va: Apparent volume of the cut sample calculated from the outer dimensions of the cut sample used for measurement (cm ³ )
W: Total weight of cut sample used for measurement (g)
ρ: density of the resin composition constituting the extruded foam plate (g / cm ³ )

(appearance)
The smoothness of the product surface was evaluated visually.
○: A smooth surface with no irregularities Δ: Some irregularities are observed during long-time operation ×: The surface is not smooth due to gas separation or the like

(Color tone of foam plate)
The color tone of the extruded foam plate obtained in Examples and Comparative Examples and the color tone of the reference extruded foam plate (conventional extruded foam plate produced by blending hexabromocyclododecane as a flame retardant) were visually compared, Evaluation was made according to the following criteria.
○: The color does not change from the standard foam board
X: Slightly yellow compared to the reference foam plate

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

(Average cell diameter in the thickness direction)
The average bubble diameter (DT: mm) in the thickness direction is measured by drawing a line segment over the entire thickness in the thickness direction at a total of three locations in the center and both ends of the vertical cross section in the width direction. The average diameter of bubbles existing on each line segment (the length of the line segment / the number of bubbles intersecting with the line segment) is obtained from the number of bubbles intersecting the line, and the arithmetic average value of the average diameters of the three obtained positions is calculated. The average cell diameter in the thickness direction (DT: mm) is used.

(Thermal conductivity)
The thermal conductivity was measured by the following method based on the accelerated test described in ISO 11561.
A test piece having no molded skin of 200 mm × 200 mm × 10 mm was cut out from the central portion of the extruded foam plate immediately after production, and the test piece was stored in an atmosphere of 23 ° C. and humidity 50%. Ten days after production, using the test piece, based on the heat flow method described in JIS A1412-2: 1999 (one specimen, symmetrical configuration method, high temperature side 38 ° C., low temperature side 8 ° C., average temperature 23 ° C.) The thermal conductivity was measured.

(Combustion quality)
Immediately after production, the extruded foam plate was transferred to a room with an air temperature of 23 ° C. and a relative humidity of 50%. After leaving in that room for 4 weeks, five test pieces were randomly cut from the extruded foam plate (N = 5), and JIS Combustibility was measured based on 5.13.1 “Measurement method A” of A9511 (2006R), and the flame retardancy of the extruded foam plate was evaluated by the average burning time (seconds) of five test pieces. In addition, it has high flame retardance, so that average combustion time is short.

(Weight average molecular weight)
The weight average molecular weights of the raw material resin, the extruded foam plate, and the recycled raw material resin were measured by gel permeation chromatography analysis.
About the recycled resin, the weight average molecular weight was measured about the pellet which melted and re-pelletized the extrusion foaming board obtained by each Example and the comparative example with the extruder for recycling.

The weight average molecular weight is a value obtained by dissolving 10 mg of a resin sample in 10 ml of tetrahydrofuran (THF), measuring by a gel permeation chromatography (GPC) analysis method, and calibrating with standard polystyrene.
Details of the GPC analysis conditions are as follows.
Equipment: GPC high performance liquid chromatograph column manufactured by GL Sciences Inc .: Showa Denko Co., Ltd., trade name ShodexGPC KF-806, KF-805, KF-803 are connected in series in this order, and column temperature used : 40 ° C
Solvent: THF
Flow rate: 1.0 mL / min Concentration: 0.15 w / v%
Injection volume: 0.2ml
Detector: UV-visible detector manufactured by GL Sciences Inc., trade name UV702 type (measurement wavelength 254 nm)
Molecular weight range of calibration curve used for calculation of molecular weight distribution: 1.2 × 10 ^{7 to} 5.2 × 10 ³

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

The results of Examples 1 to 4 show that according to the production method of the present invention, the polystyrene resin composition (a) and the flame retardant composition (b) were obtained by using the polystyrene resin composition (c) as a compatibilizing agent. This improves the kneadability and improves the extrusion stability, which indicates that it is possible to stably produce a foam plate having no surface irregularities and excellent surface smoothness and good color tone. In addition, the polystyrene-based resin composition (c) exhibits a function as a compatibilizing agent, but at the same time, since the flame retardant is uniformly and sufficiently dispersed, it also functions as a flame retardant. It shows that an extruded foam board with improved flame retardancy can be obtained.
Moreover, it turns out that the dispersibility of a flame retardant improves and the flame retardance is further improved when the compounding quantity of a polystyrene-type resin composition (b1) increases from the result of Examples 2-3.
From the results of Example 4, it is understood that the flame retardancy is further improved by using a sufficiently kneaded polystyrene resin composition (c) such as the recycled polystyrene resin composition (c2). .

Comparative Example 1 is an example in which the polystyrene resin composition (c) is not used. In Comparative Example 1, improvement in extrusion stability is not observed, and a foamed plate having no surface irregularities and good appearance cannot be stably produced for a long time. Moreover, since the polystyrene-type resin composition (c) is not contained, the flame-resistant improvement like Examples 1-4 is not seen so much.

Claims (7)

A method for producing a polystyrene resin extruded foam plate by extruding and foaming a foamable resin melt containing a polystyrene resin composition and a physical foaming agent,
The polystyrene resin composition, a polystyrene resin (a), a styrene - brominated butadiene copolymer seen containing 30 wt% or more, and a flame retardant composition comprising a thermal stabilizer (b), a polystyrene resin And a polystyrene-based resin composition (c) containing 0.1 to 10% by weight of a styrene-brominated butadiene copolymer, and the blending amount of the flame retardant composition (b) is It is 1 to 20 parts by weight with respect to 100 parts by weight of the polystyrene resin (a), and the blending amount of the polystyrene resin composition (c) is 10 to 150 parts by weight with respect to 100 parts by weight of the polystyrene resin (a). And adding the flame retardant resin composition (b) as a masterbatch or a melt-kneaded product .   The polystyrene resin extruded foam board according to claim 1, wherein a blending ratio (c / b) of the polystyrene resin composition (c) to the flame retardant composition (b) is 2 to 50. Production method. The polystyrene resin (a) has a melt viscosity (ηa) of 500 to 2500 Pa · s at 200 ° C. and a shear rate of 100 sec ⁻¹ , and the polystyrene resin composition (c) for the melt viscosity (ηa) The ratio (ηc / ηa) of the melt viscosity (ηc) under the conditions of 200 ° C. and a shear rate of 100 sec ⁻¹ is from 0.8 to 2, wherein the polystyrene-based resin according to claim 1 or 2 Method for producing extruded foam board.   The polystyrene resin composition (c) is a melt-kneaded product containing a styrene-brominated butadiene copolymer, a heat stabilizer, and a polystyrene resin. Manufacturing method of polystyrene resin extruded foam board. The heat stabilizer is one or more heat stabilizers selected from bisphenol type epoxy compounds, novolak type epoxy compounds, hindered phenol compounds, hindered amine compounds and phosphite compounds. The manufacturing method of the polystyrene-type resin extrusion foam board in any one of Claim 1 to 4 characterized by the above-mentioned. The polystyrene resin composition (c) obtained by heating and melting polystyrene resin extruded foam waste containing polystyrene-brominated butadiene copolymer and / or a pulverized product of the foamed plate. The method for producing a polystyrene-based resin extruded foam plate according to any one of claims 1 to 5, wherein: The method for producing a polystyrene-based resin extruded foam plate according to any one of claims 1 to 6, wherein the polystyrene-based resin composition (c) is pelletized .