阅读说明：本技术 发泡性苯乙烯系树脂粒子的制造方法 (Method for producing expandable styrene resin particles ) 是由 青木佑司 于 2019-07-04 设计创作，主要内容包括：本发明提供一种发泡性苯乙烯系树脂粒子的制造方法,能够抑制未反应而直接残留的苯乙烯单体的量。发泡性苯乙烯系树脂粒子的制造方法包括：通过在2,2-双[4-(2,3-二溴-2-甲基丙氧基)-3,5-二溴苯基]丙烷及含有酯基的磺酸盐的存在下进行苯乙烯系单体的悬浮聚合,而获得苯乙烯系树脂粒子的步骤；以及在所述悬浮聚合中或所述悬浮聚合后使所述苯乙烯系树脂粒子含有发泡剂的步骤。(The invention provides a method for producing expandable styrene resin particles, which can inhibit the amount of unreacted and directly remained styrene monomer. The method for producing expandable styrene resin particles comprises: a step of obtaining styrene-based resin particles by suspension polymerization of a styrene-based monomer in the presence of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group; and a step of incorporating a blowing agent into the styrene resin particles during or after the suspension polymerization.)

1. A method for producing expandable styrene resin particles, comprising:

a step of obtaining styrene-based resin particles by suspension polymerization of a styrene-based monomer in the presence of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group; and

and a step of adding a blowing agent to the styrene resin particles during or after the suspension polymerization.

2. The method for producing expandable styrene resin particles according to claim 1, wherein in the step of obtaining styrene resin particles, 1 to 7 parts by mass of the ester group-containing sulfonate is used per 100 parts by mass of the 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane.

3. The method for producing expandable styrene resin particles according to claim 1 or 2, wherein the ester group-containing sulfonate is a polyester of a polycarboxylic acid having a sulfonate structure.

Technical Field

The present invention relates to a method for producing expandable styrene resin particles.

Background

Expanded moldings of styrene resins obtained from expandable styrene resin particles are lightweight and have high heat insulation properties, and therefore are used in various fields such as building materials and household electric appliances.

On the other hand, organic compounds such as formaldehyde, toluene, xylene, and styrene which are volatilized from building materials and the like are pointed out to have adverse effects on human bodies, and therefore, it is required to suppress the amounts of these organic compounds contained in the styrene-based resin.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2007-9018

Disclosure of Invention

[ problems to be solved by the invention ]

For example, japanese patent laid-open No. 2007-9018 (patent document 1) describes a method of suppressing the amount of a styrene monomer that remains unreacted in expandable styrene resin particles, but it is desired to develop a technique that exceeds this method.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for producing expandable styrene resin particles, which can suppress the amount of unreacted styrene monomer that remains.

[ means for solving problems ]

In order to solve the above problems, a method for producing expandable styrene resin particles according to one aspect of the present invention includes: a step of obtaining styrene-based resin particles by suspension polymerization of a styrene-based monomer in the presence of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group; and a step of incorporating a blowing agent into the styrene resin particles during or after the suspension polymerization.

[ Effect of the invention ]

According to the present invention, the amount of the styrene monomer remaining in the expandable styrene resin particles without being reacted can be suppressed.

Detailed Description

First, the contents of the embodiments of the present invention are listed for explanation.

(1) A method for producing expandable styrene resin particles according to an embodiment of the present invention includes: a step of obtaining styrene-based resin particles by suspension polymerization of a styrene-based monomer in the presence of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group; and a step of incorporating a blowing agent into the styrene resin particles during or after the suspension polymerization.

By this method, the amount of the styrene monomer remaining in the obtained expandable styrene resin particles without being reacted can be suppressed.

(2) Preferably: in the step of obtaining styrene resin particles, 1 to 7 parts by mass of the ester group-containing sulfonate is used per 100 parts by mass of the 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane.

By this method, the amount of the styrene monomer remaining in the expandable styrene resin particles without being reacted can be further suppressed.

(3) Preferably: the sulfonate containing ester group is a polyester of polycarboxylic acid having a sulfonate structure.

By this method, the amount of the styrene monomer remaining in the expandable styrene resin particles without being reacted can be further suppressed.

Hereinafter, embodiments of the present invention will be described in more detail.

In the production method of the present embodiment, expandable styrene resin particles containing 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group are obtained by suspension polymerization of a styrene monomer in the presence of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and a sulfonate containing an ester group.

The styrene monomer of the present embodiment is not particularly limited, and includes: aromatic vinyl monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2, 4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α -methylstyrene, α -methyl-p-methylstyrene, 1-diphenylethylene, p- (N, N-diethylaminoethyl) styrene, p- (N, N-diethylaminomethyl) styrene, vinylpyridine and vinylnaphthalene. These may be used singly or in combination of 2 or more. Styrene is particularly preferable as the styrene monomer in the present embodiment.

In the present embodiment, another vinyl monomer copolymerizable with the styrene monomer may be used in combination. Examples of such vinyl monomers include acrylic acid esters and methacrylic acid esters of alcohols, acrylonitrile, maleic acid esters, vinyl acetate, and olefins.

Further, for the purpose of forming a crosslinked structure, a 2-functional type monomer may also be used in combination. Examples thereof include divinylbenzene and alkanediol di (meth) acrylates.

Since 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane is less likely to interfere with the polymerization reaction of styrene monomers by a chain transfer reaction (chain transfer reaction), the use of this compound as a flame retardant can improve the flame retardancy of a styrene resin foam molded article (hereinafter, also simply referred to as "foam molded article") while suppressing the increase of unreacted styrene monomers.

In the production method of the present embodiment, the amount of 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane used is preferably 0.2 to 5 parts by mass, more preferably 0.3 to 4 parts by mass, and even more preferably 0.3 to 3 parts by mass, per 100 parts by mass of the styrene-based monomer, from the viewpoint of improving the flame retardancy of the foam molded product and suppressing an increase in unreacted styrene-based monomer.

In the production method of the present embodiment, for example, a sulfonate containing an ester group is used as the dispersant. Sulfonate salts containing ester groups are believed to provide better dispersion of styrenic monomers and 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane as a flame retardant in the suspension.

By better dispersing the styrenic monomers in the suspension, the styrenic monomers can be effectively polymerized with each other, and thus the amount of unreacted styrenic monomers can be reduced.

Further, by dispersing 2, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane as a flame retardant in a suspension, the flame retardant can contribute to flame retardancy with good efficiency.

In the production method of the present embodiment, the amount of the ester group-containing sulfonate to be used is preferably 0.5 to 50 parts by mass, more preferably 0.5 to 25 parts by mass, even more preferably 1 to 7 parts by mass, and even more preferably 1 to 4 parts by mass, based on 100 parts by mass of the flame retardant, from the viewpoint of suppressing the amount of unreacted styrene-based monomer.

In the production method of the present embodiment, the amount of the ester group-containing sulfonate to be used is preferably 0.001 to 0.05 parts by mass, more preferably 0.003 to 0.04 parts by mass, even more preferably 0.004 to 0.03 parts by mass, and still more preferably 0.005 to 0.02 parts by mass, based on 100 parts by mass of the styrene-based monomer to be used, from the viewpoint of suppressing the amount of unreacted styrene-based monomer.

The ester group-containing sulfonate used in the present embodiment is not particularly limited, and 1 kind may be used singly, or 2 or more kinds may be used in combination. The ester group-containing sulfonate is preferably a polyester of a polycarboxylic acid having a sulfonate structure such as sodium dioctyl sulfosuccinate, sodium didecyl sulfosuccinate, or sodium dihexyl sulfosuccinate, and more preferably a diester of a dicarboxylic acid having a sulfonate structure such as sodium dioctyl sulfosuccinate or sodium didecyl sulfosuccinate, from the viewpoint of suppressing the amount of unreacted styrene-based monomer.

In the production method of the present embodiment, a suspending agent may be used. The suspending agent is not particularly limited, and includes: hydrophilic polymers such as polyvinyl alcohol, methyl cellulose and polyvinyl pyrrolidone, and sparingly water-soluble inorganic salts such as tricalcium phosphate, magnesium pyrophosphate, hydroxyapatite, alumina, talc, kaolin and bentonite. The amount of the suspending agent used is not particularly limited, but is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the styrene-based monomer.

In the production method of the present embodiment, for example, various other additives may be used in suspension polymerization. The additives are not particularly limited, and include: polyethylene wax, talc, silica, ethylene bis stearamide, methyl methacrylate copolymer, a bubble nucleating agent such as silicone, liquid paraffin, glycerol diacetyl monolaurate (glycerol diacetyl monolaurate), glycerol tristearate, plasticizers such as di-2-ethylhexyl phthalate and di-2-ethylhexyl adipate, chain transfer agents such as dodecylmercaptan and alpha-methylstyrene dimer, antistatic agents such as alkyldiethanolamine, glycerol fatty acid ester and sodium alkylsulfonate, antioxidants such as phenol, phosphorus and sulfur, ultraviolet absorbers such as benzotriazole and benzophenone, light stabilizers such as hindered amine, conductive carbon black, graphite powder, copper-zinc alloy powder, copper powder, silver powder, gold powder, conductive fillers such as IPBC, TBZ, BCM and TPN, organic antibacterial agents such as silver, copper, zinc, etc., conductive fillers such as IPBC, TBZ, BCM and TPN, and antibacterial agents such as silver, copper, zinc, etc, Inorganic antibacterial agents such as titanium oxide.

Further, rubber components such as butadiene rubber, styrene-butadiene rubber, isoprene rubber, ethylene-propylene rubber and the like may be added.

In the present embodiment, 2-bis [4- (2, 3-dibromo-2-methylpropyloxy) -3, 5-dibromophenyl ] propane and another flame retardant may be used in combination as the flame retardant. The other flame retardant is not particularly limited, and includes: halogen flame retardants such as hexabromobenzene, tetrabromocyclooctane, hexabromocyclododecane, tetrabromobutane, hexabromocyclohexane, tribromophenol, tetrabromobisphenol A, ethylenebisbromide 2, 2-bis (4- (3, 5-dibromo-4-hydroxyphenyl) propane condensate, 2-bis (4- (2, 3-dibromopropoxy) -3, 5-dibromophenyl) propane, decabromodiphenyl ether, octabromodiphenyl ether, perchlorocyclopentadecane, chlorinated polyethylene, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (isopropylphenyl) phosphate, non-halogen phosphorus flame retardants such as tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (chloropropyl) phosphate, tetrabromobisphenol A, and ethylene bisbromide, Halogen-containing phosphorus flame retardants such as tris (2, 3-dibromopropyl) phosphate and tris (tribromoneopentyl) phosphate, and inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcium aluminate, antimony trioxide, expandable graphite, and red phosphorus.

Further, a flame retardant auxiliary such as 2, 3-dimethyl-2, 3-diphenylbutane may be used as necessary within the range in which the intended effect of the present embodiment is achieved.

In the production method of the present embodiment, a polymerization initiator may be used. The polymerization initiator is not particularly limited, and includes: benzoyl peroxide, tert-butyl peroxy-2-ethylhexyl monocarbonate, and the like.

In the production method of the present embodiment, expandable styrene resin particles can be obtained by adding a foaming agent to styrene resin particles during or after suspension polymerization of a styrene monomer to thereby incorporate the foaming agent into the styrene resin particles.

The blowing agent of the present embodiment is not particularly limited, and includes: aliphatic hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, and cyclohexane, ethers such as dimethyl ether, diethyl ether, and furan, alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol, and halogenated hydrocarbons such as HCFC-141b, HCFC-142b, HCFC-124, HFC-152a, and HFC-134 a. These blowing agents may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The content of the foaming agent in the expandable styrene resin particles is not particularly limited, but is preferably 1 to 20 wt%, more preferably 2 to 10 wt%.

The timing of adding the blowing agent may be any of before, during and after the polymerization reaction, and from the viewpoint of suppressing the amount of unreacted styrene-based monomer, the blowing agent is preferably added at a stage at which the polymerization conversion of the styrene-based monomer is 70% or more, more preferably at a stage at which the polymerization conversion is 80% or more, and still more preferably at a stage at which the polymerization conversion is 90% or more.

The molecular weight of the polystyrene resin constituting the styrene resin particles of the present embodiment is preferably in the range of 150,000 to 350,000, and more preferably 180,000 to 300,000 in terms of weight average molecular weight (Mw). When Mw is less than 150,000, the strength of the obtained expanded bead molded article may be reduced. When Mw exceeds 350,000, the expanded particles are less likely to fuse together during molding, and the strength of the molded article may be reduced.

The expandable styrene resin particles of the present embodiment preferably have a size of 0.3mm to 3mm, more preferably 0.5mm to 2.0 mm.

The foamed molded article of the present embodiment is obtained, for example, by foaming expandable styrene resin particles to produce foamed particles, filling the foamed particles into a mold, and heating and foaming the foamed particles to weld the foamed particles to each other.

The method of foaming the expandable styrene resin particles is not particularly limited, and examples thereof include a method of foaming by heating with Steam (Steam) or the like using a foaming machine equipped with a stirring device. The method for producing the foamed molded article is not particularly limited, and examples thereof include an in-mold molding method in which a metal mold is filled with foamed particles and heated with steam or the like.