JP4282000B2 - Expandable styrene resin particles, styrene resin foam particles, and styrene resin foam particles - Google Patents

Description

  The present invention relates to an expandable styrene resin particle, a styrene resin foam particle, and a styrene resin foam particle molded body containing a phosphate ester compound and a halogen-based flame retardant and having a low content of organic volatile components.

  Styrenic resin expanded particle molded bodies obtained from expandable styrene resin particles are used in building heat insulating materials, cold insulation boxes, and the like due to their excellent heat insulating performance. As the heat insulating material for buildings, a styrene resin expanded particle molded body having flame retardancy is generally used. And in recent years, in order to cope with chemical substance hypersensitivity (so-called sick house syndrome), the heat insulating material for buildings is required to have a low content of organic volatile components.

  On the other hand, in a styrene resin expanded resin molded article, a styrene resin having a large molecular weight is generally used as a base resin in order to realize excellent mechanical properties. However, styrene resins having a large molecular weight tend to have high melt viscosity, and are used for heat insulating materials for buildings, etc., in order to ensure foaming performance of expandable styrene resin particles using the styrene resin as a base resin. , An organic solvent such as toluene or xylene is added as a plasticizer (see, for example, Patent Document 1).

  Usually, a small amount of ethylbenzene, propylbenzene or the like is contained as an impurity in the styrene monomer which is a raw material of the styrene resin. The impurities such as ethylbenzene and the unreacted styrene monomer have a function as a plasticizer and contribute to the improvement of the foaming performance of the expandable styrene resin particles.

  However, if the content of the organic volatile component acting as a plasticizer is reduced in response to the demand for the molded product of the styrene resin expanded particle having a low content of the organic volatile component, the expansion of the expandable styrene resin particle is reduced. Performance, fusing performance of styrene resin foamed particles, and secondary foam performance may be reduced, and molding processability to a styrene resin foamed particle molded product may be deteriorated.

  In order to solve such problems as deterioration of molding processability, fats and oils such as glycerin esters and phthalates are used as plasticizers instead of organic volatile components. In the case of use, there is a possibility that a new problem that the required flame retardant performance is lowered occurs.

On the other hand, as a flame retardant used for a styrene resin expanded resin molded article, a halogen flame retardant exhibits an excellent flame retardant effect, and conventionally, a halogen flame retardant has been mainly used (for example, patents). Reference 1).
However, halogen-based flame retardants, particularly halogen-based flame retardants having a phenylallyl ether structure, inhibit the styrene monomer polymerization reaction by a chain transfer reaction, lower the molecular weight of the resulting styrene resin, and increase the number of unreacted styrene monomers. In some cases, a styrenic resin having high strength and a low content of organic volatile components cannot be obtained.

JP-A-11-130898

  The present invention solves the above-described problems of the prior art. That is, despite the low content of organic volatile components, the styrenic resin foamed particle molded article exhibiting excellent mechanical properties, flame retardancy and heat insulation, and foaming excellent in foamability suitable for the production of the molded article It is an object of the present invention to provide an expandable styrene resin particle and a styrene resin expanded particle excellent in moldability.

The present invention relates to (1) expandable styrene resin particles having a total content of four kinds of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less. Expandable styrenic resin particles comprising 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphate ester compound with respect to parts by weight.
(2) The expandable styrene resin particles according to (1) above, wherein the halogen flame retardant contains one or more halogen flame retardants having a phenylallyl ether structure.
(3) The foaming property as described in (2) above, wherein the weight ratio (a / b) of the halogen-based flame retardant (a) to the phosphate ester compound (b) is 0.5 to 5 Styrenic resin particles.
(4) The expandable styrenic resin particles according to any one of (1) to (3), wherein the solubility of the phosphate ester compound in 100 g of water at 25 ° C. is 1 g or less.
(5) Styrenic resin expanded particles having a total content of four types of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less, and 100 parts by weight of the base resin of the expanded particles On the other hand, 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphoric acid ester compound are contained.
(6) A styrene-based resin expanded particle molded body having a total content of four types of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less, and the base resin 100 of the molded body A styrene-based resin expanded particle molded body containing 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphate ester compound with respect to parts by weight.
(7) The apparent density (d) is 10 to 100 kg / m ³ , and the relationship between the bending strength (B) and the apparent density (d) satisfies the following formula (1): Styrenic resin expanded particle molded body.
B / d ≧ 13 (1)
[B: bending strength (kPa), d: apparent density (kg / m ³ )]
Is a component requirement.

The expandable styrenic resin particles of the present invention are phosphoric acid ester compounds in spite of expandable styrene resin particles having a small total content of four types of organic volatile components such as toluene, xylene, ethylbenzene, and styrene monomer. By containing a specific amount, it has excellent foamability. Furthermore, since the polymerization inhibition reaction of the styrene monomer during the production of the expandable styrene resin particles is suppressed due to the low content of the halogen-based flame retardant, the content of the styrene monomer is reduced, which is obtained in a later step. The resulting styrene resin expanded particles and molded articles thereof exhibit excellent mechanical properties.
Moreover, the flame retardant improvement effect by using together with a phosphoric acid ester compound will become still higher because a halogen flame retardant shall contain 1 or more types of halogen flame retardants which have a phenyl allyl ether structure.
Further, even if the halogen flame retardant (a) is reduced by setting the weight ratio (a / b) of the halogen flame retardant (a) to the phosphoric acid ester compound (b) to 0.5 to 5. Efficiently flame retardant effect will be exhibited.
Moreover, by selecting a phosphoric acid ester compound having a solubility in 100 g of water at 25 ° C. of 1 g or less, the styrene monomer is transferred into the aqueous phase during the suspension polymerization and contaminates the waste water. The fear that the suspension system becomes unstable and the resin particles that can be obtained become large or the entire polymerization system is solidified is eliminated. Further, at the time of the polymerization, it becomes possible to polymerize a polystyrene resin having sufficient flame retardancy by adding a smaller amount of a phosphoric ester compound, and as a result, expandable styrene resin particles, styrene resin foam particles and molding thereof. A desired amount of a phosphoric acid ester compound can be reliably contained in the body, and in combination with the flame retardant effect of the halogen-based flame retardant, it exhibits stable and excellent flame retardancy.

The foamed styrene resin particles of the present invention contain a specific amount of a phosphate ester compound, although the total content of the four organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer is small. Therefore, it is excellent in molding processability such as secondary foamability and fusing property at the time of in-mold molding.
As described above, the expanded polystyrene particles of the present invention exhibit sufficient flame retardancy and excellent mechanical properties, and are adapted to the environmental guideline concentration of the Ministry of Health, Labor and Welfare related to chemical sensitivity.

The foamed particle molded body obtained by in-mold molding of the foamed particles of the present invention is long for adapting to the environmental guideline concentration of the Ministry of Health, Labor and Welfare related to chemical substance hypersensitivity because the total content of organic volatile components is small. A period of aging and curing is not required. Moreover, it is excellent in mechanical properties as described above, and exhibits sufficient flame retardancy by containing a small amount of a halogen-based flame retardant and a specific amount of a phosphoric ester compound.
Furthermore, the apparent density (d) is a 10 to 100 kg / ^{m 3,} flexural strength (B) (kPa) and apparent when the ratio B / d between the density ^{(d) (kg / m 3} ) is 13 or more, In particular, it is excellent in mechanical properties and becomes a foamed particle molded body suitable as a heat insulating material for buildings.

The expandable styrene resin particles of the present invention (hereinafter also referred to as expandable resin particles) have a total content of four organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less. Expandable styrenic resin particles comprising 0.1 to 3 parts by weight of a halogenated flame retardant and 0.1 to 3 parts by weight of a phosphoric acid ester compound with respect to 100 parts by weight of the base resin. It is what.
The styrene resin expanded particles of the present invention (hereinafter also referred to as expanded particles) are styrene having a total content of four organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less. 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphoric acid ester compound with respect to 100 parts by weight of the base resin of the foamed particles. It is what.
Furthermore, the styrene-based resin expanded particle molded body (hereinafter also referred to as expanded particle molded body) of the present invention has a total content of four organic volatile components of 0.2% by weight of toluene, xylene, ethylbenzene, and styrene monomer. The following styrene-based resin expanded particle molded body, comprising 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 0.1 parts of a phosphate ester compound with respect to 100 parts by weight of the base resin of the molded body It contains 3 parts by weight.

  The foamable resin particles, foamed particles and foamed particle molded body of the present invention contain 0.1 to 3 parts by weight, preferably 0.3 to 2 parts by weight of a halogen-based flame retardant as a flame retardant in the base resin. To do. If the content is too small, flame retardancy may not be exhibited. On the other hand, when the content exceeds 3 parts by weight, the polymerization reaction of the styrene monomer is inhibited, and the molecular weight of the styrene resin constituting the expandable resin particles, the expanded particles, and the expanded particle molded body becomes low. There is a risk that the mechanical properties such as bending strength of the foamed particle molded body will eventually decrease, or the amount of unreacted aromatic vinyl monomer increases and the content of organic volatile components is 0.2 parts by weight or less. There is a risk that it will not.

  In addition, in this invention, a flame retardance is a flame retardance which passes the combustion test (measurement method A) of JIS A 9511 (1995). That is, it means that the fire is extinguished within 3 seconds, there is no residual dust, and combustion does not exceed the combustion limit indicator line.

Examples of the halogen-based flame retardant in the present invention include aliphatic, alicyclic or aromatic bromine-based or chlorine-based halogen compounds, such as hexabromobenzene, tetrabromocyclooctane, hexabromocyclododecane, tetrabromo. Butane, hexabromocyclohexane, tribromophenol, tetrabromobisphenol A, ethylenebisbromide · 2,2-bis (4- (3,5-dibromo-4-hydroxyphenyl) propane condensate, 2,2-bis (4 -(2,3-dibromopropoxy) -3,5-dibromophenyl) propane, 2,2-bis (4- (2-allyloxy) -3,5-dibromophenyl) propane, bis (3,5-dibromo- 4-dibromopropyloxyphenyl) sulfone, tri (2,3-dibromopropyl) isocyanate Examples include nurate, 2,4,6-tribromophenol allyl ether, decabromodiphenyl ether, octabromodiphenyl ether, perchlorocyclopentadecane, chlorinated polyethylene, etc. In addition, the flame retardant effect is high and the addition amount can be reduced. Therefore, among the halogen-based flame retardants, aromatic halogen-based flame retardants, among which bromine-based flame retardants are preferable, particularly halogen-based flame retardants having a phenyl allyl ether structure, and among them, bromine-based flame retardants are preferable. Examples of the halogen-based flame retardant having 2 include 2,2-bis (4- (2-allyloxy) -3,5-dibromophenyl) propane and 2,4,6-tribromophenol allyl ether.
In addition, the said halogenated flame retardant may be used independently or may be used in mixture of 2 or more types. When using two or more types of halogenated flame retardants, the total content of the two or more types of halogenated flame retardants used is the content specified by the present invention.

  The foamable resin particles, foamed particles and foamed particle molded body of the present invention have a phosphoric acid ester compound content of 0.1 to 3 parts by weight, preferably as a plasticizer and flame retardant aid in the base resin. Contains 0.2 to 2 parts by weight. When the content is too small, the flame retardancy is insufficient. Further, in foamable resin particles, foamability may be reduced, and it may be difficult to obtain foam particles having a desired bulk density. In foamed particles, secondary foamability, fusibility, etc. at the time of in-mold molding are present. There is a possibility that the molding processability is lowered due to insufficient. On the other hand, if the content exceeds 3 parts by weight, heat resistance may be lowered, foamability control becomes difficult for foamable resin particles and foamed particles, and a change in heating dimension becomes large in the foamed molded article. The physical properties related to heat resistance may be reduced.

  Examples of the phosphate ester compound in the present invention include trimethyl phosphate, triethyl phosphate, tributyl phosphate, alkyl phosphate such as trioctyl phosphate, alkoxyalkyl phosphate such as tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, tri (isopropyl). Phenyl) phosphate, trixyl phosphate, aryl phosphate such as cresyl diphenyl phosphate, alkyl aryl phosphate such as octyl diphenyl phosphate, phosphonate, phospholinen and the like. Among the phosphoric acid ester compounds, alkyl phosphates and aryl phosphates are preferable, and triphenyl phosphate and tricresyl phosphate are particularly preferable.

  Moreover, it is preferable that the solubility with respect to 100 g of water of 25 degreeC of a phosphate ester compound is 1 g or less. If a phosphate ester compound having a solubility in 100 g of water of more than 1 g is used, there is a risk of shifting into the aqueous phase during suspension polymerization and contaminating the waste water, and the resin particles that can be destabilized in the suspension system become large. Or the entire polymerization system may solidify.

Examples of the phosphoric acid ester compound having a solubility in 100 g of water at 25 ° C. of 1 g or less include triphenyl phosphate, tricresyl phosphate, triisopropylphenyl phosphate, tributyl phosphate, tributoxyethyl phosphate, trioctyl phosphate and the like.
In addition, the said phosphate ester compound may be used independently, or 2 or more types may be mixed and used for it. When using 2 or more types of phosphate ester compounds, it is made for the total content of the 2 or more types of phosphate ester compound used to become content specified by this invention.

  Further, the expandable resin particles, the expanded particles and the expanded particle molded body of the present invention include, as necessary, aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcium aluminate, antimony trioxide, expandable graphite, red phosphorus, etc. Inorganic flame retardants and 2,3-dimethyl-2,3-diphenylbutane and other flame retardant aids may be further contained.

  The foamable resin particles, foamed particles and foamed particle molded body of the present invention have four types of organic volatile components (hereinafter referred to as toluene, xylene (m-xylene, p-xylene, o-xylene), ethylbenzene, and styrene monomer). The total content of organic volatile components is also 0.2% by weight or less, preferably 0.15% by weight or less, and more preferably 0.1% by weight or less.

  If the total content of the four organic volatile components is too large, there is a possibility that the amount of organic volatile components released into the atmosphere cannot be reduced when a foamed particle molded body is used as a heat insulating material for buildings. . If the total content of the organic volatile four components in the foamable resin particles and the foamed particles is too large, it becomes difficult to obtain a foamed particle molded body with a small amount of organic volatile components released into the atmosphere.

From the above viewpoint, the expandable resin particles, the expanded particles, and the expanded particle molded body also contain propylbenzene (n-propylbenzene, i-propylbenzene) as an impurity in the styrene resin in addition to the organic volatile four components. Therefore, the total content of the five components obtained by adding propylbenzene to the four organic volatile components is preferably 0.2% by weight or less, more preferably 0.15% by weight or less, and particularly preferably 0.1% by weight or less.
In addition, since content of the said organic volatile component is a volatile matter, it changes with time. Therefore, in the expandable resin particle of the present invention, the content of the organic volatile component in the expandable resin particle when foamed by a foaming machine is used, and in the expanded particle of the present invention, the mold is filled and molded. The content of the organic volatile component in the foamed particle of the present invention, and the content of the organic volatile component in the foamed particle molded body when used as a molded product according to the application in the foamed particle molded body of the present invention. .

In the present invention, the content of each component such as the above-mentioned organic volatile four components and propylbenzene in the expandable resin particles, the expanded particles or the expanded particle molded body is determined by using a sample such as expandable resin particles as dimethylformamide (DMF). Dissolve in water and quantify by gas chromatography.
Specifically, quantification by gas chromatography is performed according to the following procedure.
1. About 5 g of cyclopentanol is precisely weighed to the third decimal place in a 100 mL volumetric flask (the weight at this time is Wi), and DMF is added to make a total of 100 mL. This DMF solution is further diluted 100 times with DMF to make an internal standard solution.
2. About 1 g of the measurement sample is precisely weighed to the third decimal place from the expandable resin particles, the expanded particles or the expanded particle molded body to be measured, and the weight at this time is defined as W _S (g).
3. The accurately weighed sample is dissolved in about 18 mL of DMF, and 2 mL of the internal standard solution prepared in 1 above is accurately added with a whole pipette.
4). 1 μL of this solution is collected with a microsyringe and introduced into a gas chromatograph to obtain a chromatogram.
The peak area of each organic volatile component and internal standard is determined from the obtained chromatogram, and the concentration of each component is determined by the following equation (2).
Concentration of each component (% by weight) = [(W _i / 10000) × 2] × [An / Ai] × Fn ÷ W _S × 100 (2)
(W _i : cyclopentanol weight (g) when the internal standard solution was prepared, W _S : sample weight (g) dissolved in DMF, An: each organic volatile component substance at the time of gas chromatograph measurement) (Peak area, Ai: Peak area of the internal standard substance at the time of gas chromatograph measurement, Fn: Correction coefficient of each organic volatile component obtained from a calibration curve prepared in advance.)

The conditions for the gas chromatographic analysis are as follows.
Equipment used: Gas chromatograph GC-6AM manufactured by Shimadzu Corporation.
Column material: A glass column having an inner diameter of 3 mm and a length of 5000 mm.
Column packing agent: [Liquid phase name] FFAP (free fatty acid), [Liquid phase impregnation rate] 10 wt%, [Carrier name] Diatomaceous earth Chromosorb W for gas chromatography, [Carrier particle size] 60/80 mesh, [Carrier treatment method] AW-DMCS (washing, baking, acid treatment, silane treatment), [filling amount] 90mL
Inlet temperature: 250 ° C
Column temperature: 120 ° C
Detector temperature: 250 ° C
Carrier gas: N ₂ , flow rate 40 m / min.
Detector: FID (hydrogen flame ionization detector)
Detection limit: 20 ppm by weight for each component

  In the present invention, when the content of each component such as toluene, xylene, ethylbenzene, and styrene monomer in the foamable resin particles, the foamed particles or the foamed particle molded body is below the detection limit, the content of the components Is considered 0 ppm.

  The expandable resin particles of the present invention can be used in the presence of a suitable suspending agent together with a styrene monomer, a plasticizer and a polymerization initiator in a closed container equipped with a stirrer, for example, using a known apparatus. There is a method in which after dispersing in a medium, a polymerization reaction is started, and a foaming agent is added during or after the completion of polymerization to obtain expandable styrene resin particles.

  The expandable resin particles of the present invention are produced from a styrene monomer or a mixture of vinyl monomers containing styrene monomer as a main component. Examples of vinyl monomers copolymerizable with styrene monomers include styrene derivatives such as α-methylstyrene, p-methylstyrene, t-butylstyrene, chlorostyrene, bromostyrene, divinylbenzene, methyl acrylate, ethyl acrylate, Acrylic esters such as butyl acrylate, 2-ethylhexyl acrylate, butanediol diacrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, acrylonitrile, methacrylate Examples include nitrile group-containing monomers such as rhonitrile, and a mixture of two or more of these vinyl monomers may be used.

  As a polymerization initiator for polymerizing the above monomer, it is soluble in vinyl monomer and has a half-life temperature of 10 hours (when the organic oxide is decomposed at a constant temperature, the amount of active oxygen is reduced to half of the initial value in 10 hours. Benzoyl peroxide, stearoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxy 2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl Peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t Butyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexyl carbonate, t-butyl peroxybenzoate, t-amyl peroxyisopropyl carbonate, t-amyl peroxy-2-ethylhexyl carbonate, t-hexyl peroxyisopropyl carbonate , T-butylperoxy-3,5,5-trimethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylper Oxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) butane 1,1-bis (t-hexylperoxy) Organic peroxides such as 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, And azo compounds such as azobisisobutyronitrile. These polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of the vinyl monomer. If the amount is less than 0.01 part by weight, the polymerization rate is slowed, resulting in a decrease in productivity. Conversely, if it exceeds 3 parts by weight, it is uneconomical. It is preferable to use a combination of an organic peroxide having a 10-hour half-life temperature of 60 to 80 ° C. and an organic peroxide having a 10-hour half-life temperature of 80 to 120 ° C.

  Examples of the suspending agent used for polymerizing the monomer include hydrophilic polymers such as polyvinyl alcohol, methyl cellulose, and polyvinyl pyrrolidone, tertiary calcium phosphate, magnesium pyrophosphate, hydroxyapatite, aluminum oxide, talc, kaolin, and bentonite. Such as a poorly water-soluble inorganic salt can be used, and a surfactant may be used in combination as necessary. In addition, when using a water-insoluble inorganic salt, it is preferable to use together anionic surfactants, such as sodium alkylsulfonate and sodium dodecylbenzenesulfonate.

  The amount of the suspending agent used is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the aromatic vinyl monomer. When using the said slightly water-soluble inorganic salt and an anionic surfactant together, 0.05 to 3 parts by weight of the slightly water-soluble inorganic salt and an anionic surfactant are added to 100 parts by weight of the aromatic vinyl monomer. It is preferable to use 0.0001 to 0.5 parts by weight.

  In addition, aromatic vinyl monomers include polyethylene wax, talc, silica, ethylene bisstearylamide, methyl methacrylate copolymer, silicone and other cell nucleating agents, liquid paraffin, glycerol diacetomonolaurate, glycerol tristearate, Plasticizers such as di-2-ethylhexyl phthalate and di-2-ethylhexyl adipate, chain transfer agents such as dodecyl mercaptan and α-methylstyrene dimer, antistatic agents such as alkyldiethanolamine, glycerin fatty acid ester and sodium alkylsulfonate , Phenolic, phosphorus, sulfur and other antioxidants, benzotriazole and benzophenone UV absorbers, hindered amine light stabilizers, conductive carbon black, graphite powder, aluminum powder, Conductive fillers such as zinc alloy powder, copper powder, silver powder, gold powder, organic antibacterial agents such as IPBC, TBZ, BCM, TPN, inorganic antibacterial agents such as silver, copper, zinc, and titanium oxide Rubber components such as additives, butadiene rubber, styrene-butadiene rubber, isoprene rubber, and ethylene-propylene rubber may be added as long as the objects and effects of the present invention are not impaired.

In the present invention, the expandable resin particles containing a halogen-based flame retardant, a flame retardant aid added as necessary, and a phosphate ester compound are used as the styrene monomer when the styrene monomer is polymerized. It can be obtained by dissolving it in In addition, the content of the expandable resin particles of the halogen-based flame retardant and phosphate ester compound in the base resin can be adjusted by changing the amount of the substance dissolved in the styrene monomer. % By weight is contained in the polymerized polystyrene resin.
Further, the foamable resin particles are heated and foamed to obtain foamed particles containing the halogen-based flame retardant of the present invention, a flame retardant aid added as necessary, and a phosphate ester compound. By molding the foamed particles in a mold, a foamed particle molded body containing the halogen-based flame retardant of the present invention, a flame retardant aid added as necessary, and a phosphate ester compound is obtained.

In the present invention, in order to reduce the content of the organic volatile component in the expandable resin particles, the expanded particles, or the expanded particle molded body, the following method is exemplified.
For example, in order to reduce the content of the styrene monomer, a method of reducing the amount of the halogen-based flame retardant that inhibits the polymerization reaction of the styrene monomer can be used. The extent to which the amount of the halogenated flame retardant must be suppressed depends on the type of the halogenated flame retardant, but is generally 0.5 to 1 part by weight or less with respect to 100 parts by weight of the styrene monomer. preferable. As a method for reducing the amount of unreacted styrene monomer, the polymerization of the expandable resin particles is carried out by carrying out the first stage of polymerization at 70 to 110 ° C. and the second stage of polymerization at 100 to 130 ° C. It is preferable to use a combination of an organic peroxide having an initial temperature of 60 to 80 ° C and an organic peroxide having a 10-hour half-life temperature of 80 to 120 ° C.

Examples of the organic peroxide having a 10-hour half-life temperature of 60 to 80 ° C. include diacyl peroxides such as benzoyl peroxide, alkyl peresters such as t-butylperoxy-2-ethylhexanoate, 2,5- It is particularly preferable to use a bifunctional alkyl perester such as dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane. In addition, as the organic peroxide having a 10-hour half-life temperature of 80 to 120 ° C., percarbonates such as t-butylperoxy-2-ethylhexyl carbonate and t-amylperoxy-2-ethylhexyl carbonate, 1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) It is particularly preferable to use peroxyketals such as cyclohexane.
In the present specification, the 10-hour half-life temperature of the organic peroxide is usually 0.1 mol / L using a solution that is relatively inert to radicals (for example, benzene and mineral spirits). An organic peroxide solution is prepared, sealed in a glass tube subjected to nitrogen substitution, immersed in a thermostatic bath set at a predetermined temperature, and thermally decomposed for measurement.

In addition, in order to reduce the content of organic volatile components such as ethylbenzene other than styrene monomer, organic volatile components such as ethylbenzene other than styrene monomer are derived from impurities in styrene monomer. Examples include a method in which polystyrene is suspension-polymerized as described above using the obtained high-purity styrene monomer as a starting material.
However, in the present invention, the method for reducing the content of the organic volatile component in the expandable resin particles, the expanded particles, or the expanded expanded particles is not particularly limited to the above method.

  Moreover, as a foaming agent supplied in an airtight container at the time of foaming resin particle manufacture, propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, etc. aliphatic hydrocarbons, dimethyl ether , Ethers such as diethyl ether and furan, alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, halogenated hydrocarbons such as HCFC-141b, HCFC-142b, HCFC-124, HFC-152a and HFC-134a, Examples thereof include inorganic gases such as carbon and nitrogen. These foaming agents can be used alone or in combination of two or more.

  The foaming agent is supplied in an airtight container in such an amount that the foaming agent content in the expandable styrene resin particles is 1 to 20% by weight, preferably 2 to 10% by weight. The blowing agent may be added before, during or after the polymerization reaction, but is preferably added at a polymerization conversion of 70% or more of the aromatic vinyl monomer. Furthermore, it is preferable to add at a polymerization conversion rate of 80% or more. When the polymerization conversion of the aromatic vinyl monomer is less than 70% and the foaming agent is added, the unreacted aromatic vinyl monomer increases and the content of the organic volatile component is 0.2 parts by weight or less. May not be obtained.

  The molecular weight of the styrene resin particles constituting the expandable resin particles, expanded particles or expanded particle molded body of the present invention is preferably in the range of 150,000 to 350,000 in terms of weight average molecular weight (Mw). If the Mw is less than 150,000, the strength of the obtained foamed particle molded body may be lowered. When Mw exceeds 350,000, the foaming property is lowered, and it may be difficult to foam to a target foaming ratio (for example, 50 to 60 times), and it becomes difficult for the foamed particles to be fused at the time of molding. There is a possibility that the body strength is lowered. Preferred Mw is 180,000 to 300,000.

The weight average molecular weight is measured by gel permeation chromatography (GPC) analysis method by dissolving 10 mg of styrene resin constituting foamable resin particles, foamed particles or foamed particle molded body in 10 ml of tetrahydrofuran (THF). These are values calibrated with standard polystyrene.
The details of the GPC analysis conditions are as follows.
Equipment used: Tosoh SC-8020 column: Showa Denko Shodex AC-80M connected in series Column temperature: 40 ° C
Flow rate: 1.0 ml / min Detector: UV-visible light detector UV-8020 manufactured by Tosoh Corporation

The foamed particles of the present invention are obtained by foaming expandable resin particles, and the foamed particle molded body of the present invention is obtained by molding the foamed particles in a mold.
As a foaming method of the expandable resin particles, for example, using a foaming machine composed of a cylindrical container with a well-known stirring device, the foamable resin particles are put into the foaming device and stirred in the stirring device. A method of heating and foaming the expandable resin particles by introducing a heating medium such as steam is adopted.

  In addition, as a method of making the expanded particles into expanded particle molded bodies, for example, after filling the expanded particles in a mold or between a pair of upper and lower steel belts, the expanded particles are heated by introducing a heating medium such as steam. A well-known in-mold molding method is available in which the foam particles are fused to each other to obtain a foam particle molded body having an in-mold shape.

The bulk density of the obtained expanded beads as described above, 10~100kg / ^{m 3,} preferably a further 12~50kg / ^{m 3.} Moreover, it is preferable that the apparent density of a foaming particle molded object is 10-100 kg / m < ³ >, Furthermore, 12-50 kg / m < ³ >. The bulk density of the foamed particles is appropriately selected according to the apparent density of the desired foamed particle molded body and the in-mold molding conditions. Further, the apparent density of the foamed particle molded body is appropriately selected according to the intended use and intended physical properties of the molded body. If the apparent density of the foamed particle molded body is too low, the strength is insufficient. On the other hand, if the apparent density is too high, it is difficult to sufficiently exhibit the physical properties unique to the foam such as lightness, shock-absorbing property, and heat insulation. It is an economy.

In the present specification, the bulk density (kg / m ³ ) of the expanded particles is such that an empty graduated cylinder is prepared, and is left in the graduated cylinder at a relative humidity of 50%, 23 ° C., 1 atm for 2 days or more. Foamed particles (weight W1 of the foamed particles), and the weight W1 (g) of the foamed particles placed in the graduated cylinder at the bulk volume V1 (cm ³ ) of the foamed particles read from the scale of the graduated cylinder. Is divided and converted into units (W1 / V1 × 1000).
Further, in this specification, the apparent density (kg / m ³ ) of the foamed particle molded body is obtained by dividing the foamed particle molded body weight WM (g) by the volume VM (cm ³ ) determined from the outer dimensions of the foamed particle molded body. And converted into units (WM / VM × 1000).

Particularly, in the foamed particle molded body of the present invention, the apparent density (d) is 10 to 100 kg / m ³ , and the relationship between the bending strength (B) and the apparent density (d) satisfies the following formula (1): In particular, it has excellent mechanical properties and is suitable as a heat insulating material for buildings.
B / d ≧ 13 (1)
[However, B: Bending strength (kPa), d: Apparent density of foamed particle molded body (kg / m ³ )]

  The foamed particle molded body of the present invention is excellent in flame retardancy and mechanical properties in addition to the basic physical properties of the foam, and does not require long-term aging curing after product production to deal with chemical sensitivity. Therefore, the cost related to the storage curing space can be reduced and the cost is excellent. Such a foamed particle molded body is particularly suitable as a heat insulating material for buildings, a shock absorbing material for vehicles and ships, and a civil engineering material.

  Examples of the present invention and comparative examples will be described below.

Example 1
An autoclave with an internal volume of 50 L equipped with a stirrer was charged with 16 kg of deionized water, 20 g of tricalcium phosphate as a suspending agent, and 0.8 g of sodium dodecylbenzenesulfonate as a surfactant.
Subsequently, 34 g of a benzoyl peroxide aqueous diluted powder (Nippa Oil & Fats Co., Ltd. “Nyper BW”, benzoyl peroxide purity: 75% by weight), which is an organic peroxide having a 10-hour half-life temperature of 74 ° C. as a polymerization initiator, and 10 34 g of t-butylperoxy-2-ethylhexyl monocarbonate (“Perbutyl E” manufactured by NOF Corporation), which is an organic peroxide having a time half-life temperature of 99 ° C., and 2,2-bis (4- 68 g of (2-allyloxy) -3,5-dibromophenyl) propane (“Fireguard 3200” manufactured by Teijin Chemicals Ltd.), triaryl phosphate as a phosphate ester compound (mixture of isopropylated triphenyl phosphate and triphenyl phosphate) ("Reophos 65" manufactured by Ajinomoto Techno Fine Co., Ltd., solubility (25 ° C) 0.0001 g Water 100 g) 170 g was dissolved in styrene monomer 17 kg, was added to the autoclave with stirring at 230 rpm. After the atmosphere in the autoclave was replaced with nitrogen, the temperature was raised and the temperature was raised to 90 ° C. over 1 hour and a half.

After reaching 90 ° C., it was held at 90 ° C. for 6 hours, then heated to 120 ° C. over 3 hours, held at 120 ° C. for 5 hours, and then cooled to 30 ° C. over about 6 hours. During the temperature increase from 90 ° C to 120 ° C, when reaching 100 ° C, 340 g of pentane (a mixture of 80% n-pentane and 20% isopentane) and 1200 g butane (a mixture of 70% n-butane and 30% isobutane) It was press-fitted into the autoclave for 30 minutes.
After cooling, the contents are taken out, and in order to remove the tertiary calcium phosphate adhering to the surface of the expandable styrene resin particles, nitric acid is added to dissolve the tertiary calcium phosphate, and then dehydrated with a centrifuge and fluidized drying apparatus The water adhering to the surface was removed, and expandable styrene resin particles having an average particle diameter of about 1 mm were obtained.

  The obtained expandable styrenic resin particles are sieved and 0.7 to 1.4 mm particles are taken out, and N, N-bis (2- Hydroxyethyl) alkylamine (0.005 parts by weight) was added, and the mixture was further coated with a mixture of zinc stearate (0.1 parts by weight), glycerol tristearate (0.05 parts by weight) and glycerol monostearate (0.05 parts by weight).

  After 4 kg of the obtained expandable styrene resin particles were supplied in a pressure batch foaming machine (DYHL500U manufactured by Daisen Kogyo Co., Ltd.) so that the pressure in the foaming machine was 0.01 MPa and heated for about 90 seconds, 60 kg The foamed particles were obtained by drying for 2 seconds. The obtained expanded particles were aged at room temperature for 1 day, filled in a mold of a mold molding machine (manufactured by Daisen Kogyo Co., Ltd., VS500), heated at a steam pressure of 0.07 MPa for 20 seconds, sufficiently cooled, The molded product was taken out from the mold and a styrene-based resin expanded particle molded body was obtained.

  The expandable styrenic resin particles obtained as described above were excellent in expandability despite the low content of organic volatile components. Further, the styrene resin expanded particles obtained as described above were excellent in moldability despite the low content of organic volatile components. Moreover, the styrene resin expanded resin molded article obtained as described above had a low content of organic volatile components and was excellent in flame retardancy and mechanical properties.

Example 2
The same procedure as in Example 1 was performed except that 68 g of 2,4,6-tribromophenol allyl ether (“Pyroguard FR-100” manufactured by Daiichi FAR Co., Ltd.) was used as the halogen flame retardant.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Example 3
The same procedure as in Example 1 was conducted except that 170 g of triphenyl phosphate (“TPP” manufactured by Daihachi Chemical Co., Ltd., solubility (25 ° C.) 0.001 g / 100 g of water) was used as the phosphate ester compound.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Example 4
The same procedure as in Example 1 was performed except that 170 g of tricresyl phosphate (“TCP” manufactured by Daihachi Chemical Co., Ltd., solubility (25 ° C.) 0.00001 g / 100 g of water) was used as the phosphate ester compound.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Example 5
The same procedure as in Example 1 was conducted except that 340 g of triaryl phosphate “Reophos 65” was used as the phosphate ester compound.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Example 6
340 g of 2,2-bis (4- (2,3-dibromopropoxy) -3,5-dibromophenyl) propane (“Fireguard 3100” manufactured by Teijin Chemicals Ltd.) as a halogen flame retardant, and tria as a phosphate ester compound 170 g of reel phosphate “Reophos 65”, 51 g of 2,3-dimethyl-2,3-diphenylbutane (“NOFMER BC” manufactured by NOF Corporation) as a flame retardant aid, dilute benzoyl peroxide powder (“ Nipper BW ", benzoyl peroxide purity 75 wt%) 43g and t-butyl peroxy-2-ethylhexyl monocarbonate (" perbutyl E ") 25g, and after reaching 90 ° C autoclave temperature conditions, 90 ° C to 100 ° C After raising the temperature to 6.5 ° C over 6.5 hours, further raise the temperature to 120 ° C over 1.5 hours. Further, the same procedure as in Example 1 was performed except that the temperature was kept at 120 ° C. for 2.5 hours and then cooled to 30 ° C. over about 6 hours.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Example 7
68 g of 1,2,5,6-tetrabromocyclooctane (“Pyroguard FR-200” manufactured by Daiichi FAR Co., Ltd., containing 0.5% silica) as a halogen-based flame retardant, and triaryl phosphate as a phosphate ester compound 170 g of “Reophos 65”, 43 g of water-diluted powder of benzoyl peroxide (“Nyper BW”, 75% by weight of benzoyl peroxide) as a polymerization initiator, and t-butylperoxy-2-ethylhexyl monocarbonate (“Perbutyl E”) ) After 25g was used and the autoclave temperature reached 90 ° C, the temperature was raised from 90 ° C to 100 ° C over 6.5 hours, and then further raised to 120 ° C over 1.5 hours. After holding for 5 hours, the same procedure as in Example 1 was performed, except that cooling was performed to 30 ° C. over about 6 hours.
The obtained expandable styrene-based resin particles, styrene-based resin expanded particles, and styrene-based resin expanded particle molded bodies were excellent as in the case of Example 1.

Comparative Example 1
The same procedure as in Example 1 was performed except that 170 g of glycerin tristearate was dissolved in 17 kg of styrene monomer as a plasticizer without using a phosphate ester compound.
The expandable styrene resin particles obtained in Comparative Example 1 were inferior in foamability, and the styrene resin foam particles were inferior in moldability. Moreover, the obtained styrene resin expanded resin molded article was inferior in flame retardancy.

Comparative Example 2
170 g of 2,2-bis (4- (2-allyloxy) -3,5-dibromophenyl) propane “Fireguard 3200” is used as a halogen-based flame retardant, without using a phosphate ester compound, and as a plasticizer The same procedure as in Example 1 was carried out except that 130 g of liquid paraffin (“Morresco White P60” manufactured by Matsumura Oil Research Co., Ltd.) was dissolved in 17 kg of styrene monomer.
The expandable styrene resin particles obtained in Comparative Example 2 had a high content of organic volatile components. Further, the expandable styrene resin particles were excellent in foamability, and the styrene resin foam particles were excellent in molding processability, but the obtained styrene resin foam particles were inferior in mechanical properties.

Comparative Example 3
The same operation as in Comparative Example 2 was conducted except that 680 g of 2,2-bis (4- (2-allyloxy) -3,5-dibromophenyl) propane “Fireguard 3200” was used as a halogen flame retardant.
The foamable styrene resin particles, the styrene resin foam particles, and the styrene resin foam particle molded body obtained in Comparative Example 3 had a large content of organic volatile components. In addition, although the expandable styrene resin particles are excellent in foamability and the styrene resin foam particles are excellent in molding processability, the obtained styrene resin foam particles are inferior in mechanical properties and heat resistance. there were.

Comparative Example 4
The same procedure as in Example 6 was performed except that 170 g of glycerin tristearate was dissolved in 17 kg of styrene monomer as a plasticizer without using a phosphate ester compound.
The expandable styrene resin particles obtained in Comparative Example 4 were inferior in foamability, and the styrene resin foam particles were inferior in molding processability. Moreover, the obtained styrene resin expanded resin molded article was inferior in flame retardancy.

Comparative Example 5
The same procedure as in Example 1 was carried out except that no halogen-based flame retardant was used and 680 g of triaryl phosphate “Reophos 65” was used as the phosphate ester compound.
Although the expandable styrene resin particles obtained in Comparative Example 5 are excellent in foamability and the styrene resin foam particles are excellent in molding processability, the obtained styrene resin foam particle molded body is flame retardant. And it was inferior in heat resistance.

Comparative Example 6
Example except that a phosphoric ester compound was not used and 170 g of 1,2,5,6-tetrabromocyclooctane “Pyroguard FR-200” (containing 0.5% silica) was used as a halogen flame retardant. It carried out like 7.
The expandable styrene resin particles obtained in Comparative Example 6 had a high content of organic volatile components. The expandable styrene resin particles were inferior in foamability, and the styrene resin foam particles were inferior in moldability. Furthermore, the obtained styrenic resin expanded particle molded body was inferior in mechanical properties.

  Various physical properties of the foamable styrene resin particles, styrene resin foam particles, and styrene resin foam particles obtained in Examples 1 to 7 and Comparative Examples 1 to 6 are shown in Tables 1 to 6.

The meanings of the abbreviations in Tables 1 to 6 are as follows.
TBBPA / AE; 2,2-bis (4- (2-allyloxy) -3,5-dibromophenyl) propane TBP / AE; 2,4,6-tribromophenol allyl ether TBBPA / BP; 2,2-bis (4- (2,3-dibromopropoxy) -3,5-dibromophenyl) propane TBCO; 1,2,5,6-tetrabromocyclooctane TCP; tricresyl phosphate TPP; triphenyl phosphate TAP; triaryl phosphate

In the table, the evaluation of foamability, flame retardancy, and bending strength was performed as follows.
(Foaming)
About 30 g of expandable styrenic resin particles are placed in a metal box with a wire mesh on the bottom, and then the box is placed in a box-type batch pre-foaming machine, and steam with a blowing pressure of 0.08 MPa is introduced for 270 seconds. Heated. The obtained foamed particles were air-dried at room temperature for 1 day, and then the foamed particles were put into a 1 L graduated cylinder, the weight per volume of the foamed particles was measured, and the bulk density (kg / m ³ ) was measured.

(Flame retardance)
A combustion test was conducted in accordance with the combustion test (Measurement Method A) of JIS A 9511 (1955), the average fire extinguishing time was within 1.5 seconds, there was no residual dust, and combustion did not continue beyond the combustion limit indicator line. ◎, when the average fire extinguishing time is 3 seconds, there is no residual dust and the combustion limit indicator line is exceeded and combustion does not continue ○ ○ When the combustion continues for more than 3 seconds or exceeds the combustion limit indicator line The case was marked with x.

(Bending strength)
The foamed particle molded body was cut to prepare a test piece (with a single-sided skin) having a length of 300 mm, a width of 75 mm, and a thickness of 25 mm, and a test speed of 10 mm in accordance with JIS K 7221-2 (1999) and Annex 1. A three-point bending test was performed with the skin surface as the bottom surface under the conditions of / min, the maximum load was measured, and the bending strength was calculated.

Claims (7)

  Expandable styrene resin particles having a total content of four types of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less, based on 100 parts by weight of the base resin of the resin particles Expandable styrenic resin particles comprising 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphate ester compound.   2. The expandable styrene resin particles according to claim 1, wherein the halogen flame retardant contains at least one halogen flame retardant having a phenyl allyl ether structure.   3. The expandable styrenic resin particles according to claim 2, wherein the weight ratio (a / b) of the halogen-based flame retardant (a) to the phosphate ester compound (b) is 0.5 to 5. .   The expandable styrene resin particles according to any one of claims 1 to 3, wherein the solubility of the phosphate ester compound in 100 g of water at 25 ° C is 1 g or less.   Styrenic resin expanded particles having a total content of four kinds of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less, based on 100 parts by weight of the base resin of the expanded particles Further, 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphoric acid ester compound are contained.   A styrene-based resin expanded particle molded body having a total content of four types of organic volatile components of toluene, xylene, ethylbenzene, and styrene monomer of 0.2% by weight or less, and 100 parts by weight of the base resin of the molded body On the other hand, 0.1 to 3 parts by weight of a halogen-based flame retardant and 0.1 to 3 parts by weight of a phosphate ester compound are contained. The styrenic resin according to claim 6, wherein the apparent density (d) is 10 to 100 kg / m ³ , and the relationship between the bending strength (B) and the apparent density (d) satisfies the following formula (1). Expanded particle molded body.
B / d ≧ 13 (1)
[B: bending strength (kPa), d: apparent density (kg / m ³ )]