JP6872972B2 - Method for Producing Expandable Polystyrene Resin Particles, Method for Producing Polystyrene Pre-Expanded Particles, and Method for Producing Foamed Mold - Google Patents

Description

The present invention relates to a method for producing foamable polystyrene-based resin particles containing a copolymer composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer having a functional group.

Polystyrene-based foam molded products are widely used in containers, packaging materials, building civil engineering materials, automobile materials, etc. due to their light weight and cushioning performance.

However, the foamed molded product made of foamable polystyrene resin has a problem that when the foamed molded products are rubbed against each other, other resin members, steel plates, or the like, an unpleasant rubbing noise called squeaking is likely to occur. In particular, in the field of automobile parts, vibration is likely to occur when traveling on rough roads, and the generation of rubbing noise causes a loss of usability.

In order to solve such a problem, a foam molded product in which an aliphatic compound or a silicone compound is coated on the surface or kneaded with resin particles is disclosed. For example, Patent Document 1 describes a method of suppressing the generation of rubbing noise with a foamed particle molded product composed of fatty acid amide and thermoplastic resin pre-expanded particles in which a monoester of saturated fatty acid and glycerin is adhered to the surface.

Further, Patent Document 2 describes a method of suppressing the generation of rubbing noise with a foamed particle molded body composed of foamed particles to which a hydrocarbon wax and dimethylpolysiloxane are attached.

However, in these publications, since a large amount of lubricating components are applied to the surface of the foamed particles, there are problems such as deterioration of the rubbing noise prevention performance due to peeling of these components and contamination of the pre-foaming machine and the molding die.

On the other hand, as an example of allowing the silicone compound to exist on the surface of the resin particles, Patent Document 3 describes a method of reducing the aggregation of the foamed particles by coating the surface of the foamable particles with dimethylpolysiloxane. Further, Patent Document 4 describes a method of uniformly kneading organosiloxane into foamable polystyrene-based resin particles to homogenize the bubbles of the foamed particles and obtain a foamed molded product having excellent mechanical strength and heat insulating properties. ..

However, when considering the suppression of rubbing noise, the effect cannot be obtained by adding a small amount as described in these patent documents.

Further, Examples of Copolymerizing a Macromonomer with a Styrene-based Monomer are described in Prior Documents 5 to 8. However, none of these methods is expected to suppress rubbing noise from the macromonomer.

Japanese Unexamined Patent Publication No. 2013-100443 Japanese Unexamined Patent Publication No. 2015-017155 Japanese Unexamined Patent Publication No. 2013-142106 Japanese Unexamined Patent Publication No. 2012-214750 Japanese Unexamined Patent Publication No. 08-134252 WO2006 / 106653 Japanese Unexamined Patent Publication No. 2008-231175 Japanese Unexamined Patent Publication No. 2011-246588

In view of the above circumstances, the present invention provides an effervescent polystyrene-based resin capable of obtaining a foamed molded product capable of suppressing rubbing noise without applying a large amount of an adhering agent and without contaminating a prefoaming machine or a molding die. It is an object of the present invention to provide a manufacturing method capable of obtaining particles.

As a result of diligent studies, the present inventors have completed the present invention by copolymerizing polysiloxane only on the surface of polystyrene particles in order to obtain a foamed molded product capable of suppressing rubbing noise. That is, the present invention is as follows.

The first aspect of the present invention is a method for producing foamable polystyrene-based resin particles containing a copolymer composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer having a functional group, wherein the styrene-based monomer is used. At the time when the polymerization conversion rate is 60% or more and 99% or less, at the same time as the initiator for generating radicals, 0.5% by weight or more of the polystyrene-containing macromonomer monomer having a functional group with respect to 100% by weight of the copolymer. The present invention relates to a method for producing foamable polystyrene-based resin particles, which comprises adding 11.0% by weight or less at a rate of 0.2% by weight / hr or more and 10.0% by weight / hr or less.

The second aspect of the present invention is that the addition rate of the polysiloxane-containing macromonomer monomer having a functional group is 0.4% by weight or more and 8.0% by weight / hr or less with respect to 100% by weight of the copolymer. The present invention relates to a method for producing foamable polystyrene-based resin particles according to the first invention.

A third aspect of the present invention relates to the method for producing foamable polystyrene-based resin particles according to the first or second invention, wherein the initiator that generates radicals is a peroxide-based initiator.

A fourth aspect of the present invention is any of the first to third aspects of the present invention, wherein the amount of the polysiloxane-containing macromonomer monomer having a functional group added is 0.8% by weight or more and 10.2% by weight or less. The present invention relates to a method for producing the foamable polystyrene-based resin particles described in the above.

Fifth of the present invention relates to the method for producing foamable polystyrene-based resin particles according to any one of the first to fourth inventions, wherein the main component of the surface layer portion is polysiloxane.

A sixth aspect of the present invention relates to a method for producing polystyrene-based prefoamed particles, which comprises pre-foaming the effervescent polystyrene-based resin particles according to any one of the first to fifth aspects.

A seventh aspect of the present invention relates to a method for producing a foamed molded article, which comprises molding the polystyrene-based prefoamed particles according to the sixth aspect of the invention.

According to the present invention, it is possible to obtain foamable polystyrene-based resin particles capable of obtaining a foamed molded product capable of suppressing rubbing noise without applying a large amount of an adhering agent and without contaminating a prefoaming machine or a molding die. Provide a method.

The method for producing foamable polystyrene-based resin particles of the present invention is a method for producing foamable polystyrene-based resin particles containing a copolymer composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer having a functional group. When the polymerization conversion rate of the styrene-based monomer is 60% or more and 99% or less, at the same time as the initiator for generating radicals, a single amount of polysiloxane-containing macromonomer having a functional group with respect to 100% by weight of the copolymer. It is characterized in that 0.5% by weight or more and 11.0% by weight or less of the body is added at a rate of 0.2% by weight / hr or more and 10.0% by weight / hr or less.

The timing of addition of the polysiloxane-containing macromonomer monomer in the present invention is such that the polymerization conversion rate of the polystyrene-based resin particles is 60% or more and 99% or less, and more preferably 75% or more and 95% or less. If the polymerization conversion rate is less than 60%, the particles tend to aggregate with each other, resulting in abnormal polymerization. When the polymerization conversion rate exceeds 99%, the polymerization reaction between the styrene resin particles and the polysiloxane-containing macromonomer monomer does not proceed and tends to aggregate.

The monomer composition of the base resin constituting the foamable polystyrene-based resin particles in the present invention is 89.0% by weight or more and 99.5% by weight or less of the styrene-based monomer with respect to 100% by weight of the copolymer, and poly. The siloxane-containing macromonomer monomer is 0.5% by weight or more and 11.0% by weight or less (the total amount of the styrene-based monomer and the polysiloxane-containing macromonomer monomer is 100% by weight), and more preferably styrene. The system monomer is 89.8% by weight or more and 99.2% by weight or less, and the polysiloxane-containing macromonomer monomer is 0.8% by weight or more and 10.2% by weight or less. If the ratio of the polysiloxane-containing monomer component is large, the foaming agent tends to come off, so that the foamability and moldability tend to be inferior, and it is difficult to obtain a foamed molded product having a beautiful surface. If the amount of the polysiloxane-containing monomer component is small, the rubbing noise suppression performance is not sufficiently exhibited.

The addition rate of the polysiloxane-containing macromonomer monomer having a functional group in the present invention is 0.2% by weight or more and 10.0% by weight / hr or less with respect to 100% by weight of the copolymer, which is more preferable. Is 0.4% by weight / hr or more and 8.0% by weight / hr or less. If the addition rate is less than 0.2% by weight / hr, the productivity deteriorates and it is not suitable for mass production. When the addition rate exceeds 10.0% by weight / hr, the particles being polymerized tend to aggregate with each other, resulting in abnormal polymerization.

The functional group of the polysiloxane-containing macromonomer monomer having a functional group used in the present invention is not particularly limited as long as it is a functional group that reacts with the styrene-based monomer, but is reactive with the styrene-based monomer. A vinyl group is preferable, and a methacryloyl group or an acryloyl group is more preferable.

Examples of the main chain constituting the polysiloxane-containing macromonomer monomer having a functional group include polyorganosiloxane such as polydimethylsiloxane, polymethylphenylsiloxane, and polydimethylsiloxane-diphenylsiloxane copolymer, and side chain alkyl groups. Polyorganohydrogensiloxane or the like in which a part is substituted with a hydrogen atom can be used. Of these, polydimethylsiloxane, polymethylphenylsiloxane, and polydimethylsiloxane-diphenylsiloxane copolymer are preferable, and polydimethylsiloxane is most preferable because it is economically easily available.

The number of functional groups of the polysiloxane-containing macromonomer monomer having a functional group is preferably 1.5 or more, and more preferably 1.7 or more. If the number of functional groups is less than 1.5, the reactivity with the styrene-based monomer is low, and the copolymerization tends to be difficult. The upper limit is 50.0 or less, preferably 30.0 or less, and more preferably 10.0 or less. If the number exceeds 50.0, a reaction between the polysiloxane-containing macromonomers occurs, and there is a problem that the reactivity with the styrene-based monomer deteriorates.

The polysiloxane-containing macromonomer monomer having a functional group has a functional group because it copolymerizes with a styrene-based monomer. It is more preferable to have at least a plurality of functional groups per molecule on the side chain or both ends. The functional group equivalent of the functional group is preferably 100 g / mol or more and 20,000 g / mol or less, and more preferably 1,000 g / mol or more and 10,000 g / mol or less. When the functional group equivalent is less than 100 g / mol, the polymerization of polysiloxane-containing macromonomers increases, so that it tends to be difficult to obtain a copolymer with styrene. When the functional group equivalent exceeds 20,000 g / mol, the reactivity with the styrene-based monomer is low, so that it tends to be difficult to copolymerize.

The method for obtaining the polysiloxane-containing macromonomer monomer having the functional group is not particularly limited, and a solution polymerization method, a suspension polymerization method, an emulsion polymerization method and the like are used.

As a method for producing a side-chain type polysiloxane-containing macromonomer monomer, for example, a cyclic, linear or branched organosiloxane, preferably a cyclic organosiloxane, is used with a catalyst such as an acid, an alkali, a salt or a fluorine compound. And the method of polymerization can be mentioned. The polystyrene-equivalent weight average molecular weight (Mw) of the organosiloxane used for the polymerization is preferably 20,000 or less, more preferably 10,000 or less. In the above method, a method using a silane having a functional group and / or a cyclic, linear or branched organosiloxane having a functional group together with the organosiloxane can be more preferably mentioned.

Alternatively, it has a polysiloxane having a polystyrene-equivalent weight average molecular weight (Mw) of preferably 20,000 or more, more preferably 50,000 or more, and further 100,000 or more, and preferably a functional group in a solution, a slurry, or an emulsion. A method of equilibrating a cyclic, linear or branched organosiloxane having a silane and / or a functional group in the presence of a catalyst or the like as described above can be mentioned.

Further, the method for producing the side chain type polysiloxane-containing macromonomer can be obtained, for example, by a known emulsion polymerization method described in JP-A-2006-291122.

That is, a cyclic siloxane represented by 1,3,5,7-octamethylcyclotetrasiloxane, and / or a bifunctional silane having a hydrolyzable group such as dimethyldimethoxysilane, and if necessary, methyltriethoxysilane and tetra. Trifunctional or higher alkoxysilanes such as propyloxysilane, condensates of trifunctional or higher silanes such as methyl orthosilicate, and optionally mercaptopropyldimethoxymethylsilane, acryloyloxypropyldimethoxymethylsilane, methacryloyloxypropyldimethoxymethylsilane , Vinyldimethoxymethylsilane, Vinylphenyldimethoxymethylsilane, and other functional groups can be used to obtain polysiloxane-containing macromonomonates. Of these, methacryloyloxypropyldimethoxymethylsilane is preferable from the viewpoint of copolymerization with a styrene-based monomer.

The viscosity of the polysiloxane-containing macromonomer monomer ^{is preferably 10 mm 2} / s or more, more preferably 50 mm ² / s or more at 25 ° C. as a kinematic viscosity. The higher the viscosity, the longer the siloxane chain, and the more likely it is that the rubbing noise suppression performance will be exhibited.

The molecular weight of polysiloxane, which is the main chain of the polysiloxane-containing macromonomer monomer having a functional group, is preferably 1,000 or more and 500,000 or less in terms of polystyrene-equivalent weight average molecular weight obtained by using GPC, and is preferably 3,000 or more and 300,000 or less. Is more preferable. The higher the molecular weight, the longer the siloxane chain, so the rubbing noise suppression performance is likely to be exhibited, but if the viscosity is too high, the handleability deteriorates and polymerization becomes difficult.

The foamable polystyrene-based resin particles of the present invention preferably contain polysiloxane as the main component of the surface layer portion.

The surface layer portion in the present invention indicates a range of 30 nm or more and 250 nm or less from the outermost layer of the foamable polystyrene-based resin particles, and the main component is polysiloxane, and the polysiloxane component is 50% by weight based on 100% by weight of the copolymer. It is in a state of being contained in% or more, preferably 70% by weight or more, and more preferably 90% by weight or more.

If the content of polysiloxane, which is the main component, is less than 50% by weight, the rubbing noise suppression performance tends to be difficult to develop.

The gel content insoluble in THF in the present invention is preferably 5 wt% or more and 45 wt% or less, and more preferably 12 wt% or more and 40 wt% or less. If the gel content is less than 5 wt%, the rubbing noise suppression performance is not sufficiently exhibited. If the gel content exceeds 45 wt%, the foamability and moldability tend to be inferior, and it tends to be difficult to obtain a foamed molded product having a beautiful surface.

The polystyrene-equivalent weight average molecular weight of the effervescent polystyrene-based resin particles of the present invention measured by GPC, which is a component soluble in THF, is preferably 200,000 or more and 400,000 or less, and more preferably 250,000 or more and 350,000 or less. If the weight average molecular weight is low, the mechanical strength such as compressive strength when used as a member tends to be inferior, and if it is high, it is difficult to obtain a molded product having good surface properties. In the present invention, bifunctional monomers such as divinylbenzene and hexanediol di (meth) acrylate can be used for adjusting the molecular weight.

As the styrene-based monomer used in the present invention, for example, styrene-based derivatives such as styrene, α-methylstyrene, paramethylstyrene, t-butylstyrene, and chlorostyrene can be used. These styrene-based monomers may be used alone or in combination of two or more. In particular, styrene is preferable because it has good foamability and molding processability.

In the present invention, a monomer copolymerizable with styrene may be used as the styrene-based monomer as long as the effect of the present invention is not impaired. Examples of the components that can be copolymerized with styrene include esters of acrylic acid and methacrylic acid such as methyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and cetyl methacrylate, and various simple compounds such as acrylonitrile, dimethyl fumarate and ethyl fumarate. It also includes difunctional monomers such as weights, divinylbenzene and alkylene glycol dimethacrylate. One or two or more of these copolymerizable components may be used for copolymerization.

Since these are added to the styrene-based monomer in the present invention, unless the total amount of styrene and other monomers is 89.0% by weight or more and 99.5% by weight or less with respect to 100% by weight of the copolymer. It doesn't become.

In the present invention, when the polymerization conversion rate of the styrene-based monomer is 60% or more and 99% or less, the polysiloxane-containing macromonomer monomer must be added and the radical-generating initiator must be added at the same time. As the initiator for generating radicals, a peroxide-based initiator and / or an azo compound-based initiator is preferable, and a peroxide-based initiator is more preferable. Typical examples are benzoyl peroxide, lauroyl peroxide, t-butylperoxybenzoate, isopropyl-t-butylperoxycarbonate, butyl perbenzoate, and t-butylperoxy-2-ethylhexanoate. , T-butyl perpivalate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyhexahydroterephthalate, 1,1-di (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1, Organic excesses such as 1-bis (t-amylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexyl monocarbonate, etc. Examples thereof include oxides and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. These polymerization initiators may be used alone or in combination of two or more.

As a method for producing the foamable resin particles of the present invention, a method of polymerizing a styrene-based monomer in an aqueous suspension, suspend-polymerizing, and then adding a polysiloxane-containing macromonomer monomer to polymerize. Alternatively, by continuously or intermittently adding the styrene-based monomer and the polysiloxane-containing monomer to the aqueous suspension containing the polystyrene-based resin particles, the styrene-based monomer and the poly are added to the polystyrene-based resin particles. Examples thereof include a so-called seed polymerization method in which a siloxane-containing macromonomer monomer is impregnated and polymerized.

The aqueous suspension refers to a state in which resin particles and monomer droplets are dispersed in water or an aqueous solution, and a water-soluble surfactant or monomer may be dissolved in water, or water. Insoluble dispersants, initiators, chain transfer agents, cross-linking agents, air bubble modifiers, flame retardants, plasticizers and the like may be dispersed together.

The weight ratio of resin to water is preferably 1.0 / 0.6 to 1.0 / 3.0 as the obtained resin / water ratio.

In the suspension polymerization of the present invention, it is preferable that after the first-stage polymerization is carried out and the main reaction is carried out, the residual monomer is reduced by the second-step polymerization reaction at a higher temperature than the first step.

As the polymerization initiator used in the first-stage polymerization, a radical-generating polymerization initiator generally used for producing a thermoplastic polymer can be used, and typical examples thereof are benzoyl peroxide and lauroyl. Peroxide, t-butylperoxybenzoate, isopropyl-t-butylperoxycarbonate, butyl perbenzoate, t-butylperoxy-2-ethylhexanoate, t-butylperpivalate, t-butylperoxyisopropyl Carbonate, di-t-butylperoxyhexahydroterephthalate, 1,1-di (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-amylperoxy) -3,3 , 5-trimethylcyclohexane, 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexyl monocarbonate, and other organic radicals, azobisisobutyronitrile, azobisdimethyl Examples include azo compounds such as valeronitrile. These polymerization initiators may be used alone or in combination of two or more.

Dispersants that can be used for suspension polymerization include, for example, poorly water-soluble inorganic salts such as calcium tertiary phosphate, magnesium pyrophosphate, hydroxyapatite, and kaolin, and water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, and polyvinylpyrrolidone. When a poorly water-soluble inorganic salt is used, it is effective to use an anionic surfactant such as α-olefin sulfonic acid sodium and dodecylbenzene sulfonic acid sodium in combination. These dispersants may be added in the middle of the polymerization if necessary.

The amount of the dispersant used depends on the type, but is 0.1 part by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of water as a poorly water-soluble inorganic salt, and 30 ppm as an anionic surfactant or water-soluble polymer. More than 500 ppm is preferable.

Examples of the foaming agent include ozone depletion of aliphatic hydrocarbons such as propane, isobutane, normal butane, isopentane, normal pentane, and neopentane, which are hydrocarbons having 3 or more and 5 or less carbon atoms, such as difluoroethane and tetrafluoroethane. Examples thereof include volatile foaming agents such as hydrocarbons having a coefficient of zero. These foaming agents may be used in combination. The amount used is preferably 4 parts by weight or more and 10 parts by weight or less, and more preferably 5 parts by weight or more and 9 parts by weight or less with respect to 100 parts by weight of the polystyrene-based resin particles. If the amount of the foaming agent is small, it is difficult to obtain the foaming ratio, and if the amount of the foaming agent is large, the resin tends to aggregate in the foaming agent impregnation step.

As the additive used in the present invention, a solvent, a plasticizer, a bubble adjusting agent, an external additive, a flame retardant and the like can be used depending on the purpose.

Examples of the solvent include those having a boiling point of 50 ° C. or higher, and examples thereof include C6 or higher aliphatic hydrocarbons such as toluene, hexane and heptane, and C6 or higher alicyclic hydrocarbons such as cyclohexane and cyclooctane.

Examples of the plasticizing agent include high boiling point plasticizing agents having a boiling point of 200 ° C. or higher. Examples thereof include vegetable oils such as palm kernel oil, aliphatic esters such as dioctyl adipate and dibutyl sebacate, liquid paraffin, and organic hydrocarbons such as cyclohexane.

Examples of the bubble adjusting agent include aliphatic bisamides such as methylene bisstearic acid amide and ethylene bisstearate amide, and polyethylene wax.

Specific examples of the external preparation include fatty acid triglycerides such as triglyceride laurate, triglyceride stearate, triglyceride linoleic acid, and triglyceride hydroxystearate, diglyceride laurate, diglyceride stearate, and diglyceride linoleic acid, and lauric acid. Fatty acid monoglyceride such as monoglyceride, monoglyceride stearate, monoglyceride linoleic acid, vegetable oil such as castor oil, soybean oil, olive oil, fatty acid metal salt such as zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, zinc laurate, calcium laurate. , Polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene laurate, polyoxyethylene palmitate, polyoxyethylene stearate, nonionic surfactants such as polyoxyethylene oleate, etc. Can be mentioned. These external additives and attachments may be used alone or in combination of two or more. Of these, triglyceride stearate and castor oil are preferable because they promote the fusion of foams. Further, these external additives and attachments may be added to the water system when impregnated with the foaming agent, or may be added and coated after dehydration or drying, regardless of the coating method. A preferred coating method is a method of coating by attaching after drying and mixing and stirring.

As the flame retardant and the flame retardant aid used in the present invention, known and commonly used ones can be used.

Specific examples of the flame retardant include halogenated aliphatic hydrocarbon compounds such as hexabromocyclododecane, tetrabromobutane, and hexabromocyclohexane, tetrabromobisphenol A, tetrabromobisphenol F, 2,4,6-tri. Brominated phenols such as bromophenol, tetrabromobisphenol A-bis (2,3-dibromopropyl ether), tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A- Brominated phenol derivatives such as diglycidyl ether, 2,2-bis [4'(2 ", 3" -dibromoalkoxy) -3', 5'-dibromophenyl] -propane, brominated styrene-butadiene block copolymer , Brobroinated random styrene / butadiene copolymer, brominated butadiene / vinyl aromatic hydrocarbon copolymer such as brominated styrene / butadiene graph and copolymer (for example, EMERALD3000 manufactured by Chemtura, and Special Table 2009-516019). Disclosed in the Gazette) and the like. These flame retardants may be used alone or in combination of two or more.

As a specific example of the flame retardant aid, for example, an initiator such as cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane may be used. ..

The obtained foamable polystyrene-based resin particles can be made into pre-foamed particles by a general pre-foaming method. Specifically, it is placed in a container equipped with a stirrer and heated by a heat source such as steam to perform preliminary foaming up to a desired foaming ratio.

Further, the effervescent styrene-based prefoamed particles can be molded by a general in-mold molding method to obtain a foamed molded product. Specifically, it is filled in a mold that can be closed but cannot be closed, and heat-fused with steam to obtain a styrene-based foamed molded product.

The styrene-based foamed molded product of the present invention was pre-foamed at a foaming ratio of 45 times, and the rubbing noise when molded was evaluated.

Examples and comparative examples are given below, but the present invention is not limited thereto.

<GPC measurement>
0.02 g of the foamable polystyrene-based resin particles were dissolved in 20 ml of tetrahydrofuran (hereinafter, may be abbreviated as "THF") with respect to the obtained foamable polystyrene-based resin particles, and then the gel component was filtered. Next, GPC measurement was performed on only the components soluble in THF using a gel permeation chromatograph (GPC) under the following conditions, and the GPC measurement chart, weight average molecular weight (Mw) and number average molecular weight (Mw) and number average molecular weight ( Mn) was obtained. The obtained value is a relative value in terms of polystyrene.
Measuring device: High-speed GPC device HLC-8220 manufactured by Tosoh Corporation
Column used: Tosoh Co., Ltd., SuperHZM-H x 2, SuperH-RC x 2 Column temperature: 40 ° C, mobile phase: THF (tetrahydrofuran)
Flow rate: 0.35 ml / min, injection volume: 10 μl
Detector: RI.

<Manufacturing of preliminary foamed particles>
Expandable polystyrene-based resin particles classified into a predetermined particle size by a sieve are blown into a prefoaming machine "Daikai Kogyo, BHP" under the condition of a vapor pressure of 0.09 to 0.12 MPa to a bulk magnification of 45 times. After that, the particles were left at room temperature for 1 day to obtain pre-foamed particles having a bulk ratio of 45 times.

<Manufacturing of foam molding>
The obtained styrene-based prefoamed particles were blown into the mold using a molding machine "Daisen, KR-57" and molded in the mold at a vapor pressure of 0.10 MPa to form a flat plate having a thickness of 25 mm and a length of 400 mm and a width of 350 mm. Foam molded article was obtained.

<Surface property of molded product>
The state of the surface of the foam molded product was evaluated by visual observation. The larger the value, the more beautiful the surface condition with less gaps between the particles, and a score of 3 or more expressed on a scale of 5 was considered acceptable.
5: No gaps are found 4: There are some gaps, but I can hardly understand them 3: There are some gaps, but they are acceptable as a whole 2: The gaps are conspicuous 1: There are many gaps.

<Measurement of static friction coefficient>
A test piece of a single-sided skin having a length of 60 mm, a width of 60 mm, and a thickness of 4 mm was cut out from the obtained foam molded product using a vertical slicer (manufactured by Sakura Engineering).

The test piece was allowed to stand still in a constant temperature and humidity chamber having a temperature of 23 ° C. and a humidity of 50% for 12 hours. Then, under the same environment, the test piece was rubbed against the iron plate 10 times with a surface tester HEIDON Type: 14FW (manufactured by Shinto Kagaku Co., Ltd.) under the conditions of a load of 200 g, a reciprocating distance of 50 mm, and a sliding speed of 3000 mm / min. The average value of the coefficient of static friction for each rubbing was calculated.

<Measurement of rubbing sound>
A rectangular parallelepiped test piece of a double-sided skin having a length of 300 mm, a width of 60 mm, and a thickness of 25 mm was cut out from the obtained foam molded product using a vertical slicer (manufactured by Sakura Engineering). Further, a test piece of a triangular prism having a double-sided skin having a base of 120 mm, a height of 60 mm and a thickness of 25 mm was cut out, and both were allowed to stand in a constant temperature and humidity chamber having a temperature of 23 ° C. and a humidity of 50% for 12 hours. Then, under the same environment, the test piece of the triangular prism was placed on the test piece of the rectangular parallelepiped so that the corners touched, and a load of 2000 g was placed on the test piece of the triangular pyramid. In that state, the test piece was reciprocated 10 times in a section having a width of 50 mm at a speed of 6000 mm / min.

The rubbing sound generated at that time was measured with a sound collecting microphone over a wide range and sound pressure. The highest sound pressure was sought in the range of 5,000 or more and 20,000 Hz or less, which humans find unpleasant.

<Combustion speed>
The obtained in-mold foam molded product was cut into a sample having a length of 356 mm, a width of 101.6 mm and a thickness of 12 mm using a heat ray slicer to obtain a test piece for a combustion test.
The burning rate was evaluated using the obtained test pieces by a method in accordance with the US automobile safety standard FMVSS302.

The flame spread rate was calculated by the following formula.
Combustion rate (mm / min.) = 60 * (D / T)
D: Distance traveled by the flame (mm), 25.4 cm when the fire spreads to the end
T: Time required for fire spread (seconds)
The evaluation was based on the following criteria.
○: Self-erasing before the marked line.
X: Combustion speed 80 mm / min. Super.

<Macromonomer species containing polysiloxane used>
MPS: Side-chain type methacryloyl-containing polysiloxane (molecular weight: 200,000, viscosity: unknown, number of functional groups: 7.5, functional group equivalent: 9300 g / mol)
X-22-164B: Double-ended methacryloyl-containing polysiloxane (molecular weight: 0.35 million, viscosity: 55 mm ² / s, number of functional groups: 2.1, functional group equivalent: 1630 g / mol) (manufactured by Shinetsu Silicone Co., Ltd.)
KF-96-50: Didimethylpolysiloxane (Molecular weight: 0.35 million, Viscosity: 50 mm ² / s, No functional group) (manufactured by Shinetsu Silicone Co., Ltd.)
KF-96-300: Didimethylpolysiloxane (Molecular weight: 15,000, Viscosity: 300 mm ² / s, No functional group) (manufactured by Shinetsu Silicone Co., Ltd.)
KF-2012: Single-ended methacryloyl-containing polysiloxane (molecular weight ^{: 0.4 million, viscosity: 60 mm 2} / s, number of functional groups: 0.8, functional group equivalent: 4600 g / mol) (manufactured by Shinetsu Silicone Co., Ltd.)
X-22-2426: Single-ended methacryloyl-containing polysiloxane (molecular weight 1,000,000 :, viscosity: 200 mm ² / s, number of functional groups: 0.8, functional group equivalent: 12000 g / mol) (manufactured by Shin-Etsu Silicone Co., Ltd.) ..

<Initiator type used>
HTP: Di-t-butylperoxyhexahydroterephthalate (10-hour half-life temperature 83 ° C) (manufactured by Kayaku Akzo: Kayaester HTP-65W)
PBE: t-butylperoxy-2-ethylhexyl monocarbonate (10-hour half-life temperature 99 ° C.) (manufactured by NOF CORPORATION: Perbutyl E).

(Example 1)
<Manufacturing of polystyrene resin seed particles>
In a reactor equipped with a stirrer, 100 parts by weight of pure water, 0.4 parts by weight of tricalcium phosphate, 0.01 parts by weight of sodium dodecylbenzenesulfonate, 0.5 parts by weight of sodium chloride, and polyethylene wax as a nucleating agent 0. After adding 07 parts by weight and stirring to form an aqueous suspension, 0.2 parts by weight of benzoyl peroxide and 1,1-bis (t-butylperoxy) were added to 100 parts by weight of the styrene monomer as a polymerization initiator. ) Dissolve 0.2 part by weight of cyclohexane, add to the reactor, heat to 98 ° C., polymerize for 4.5 hours, cool, take out the contents, dehydrate and dry, and sieve. To obtain polystyrene-based resin seed particles having a particle diameter of 0.4 to 0.5 mm.

<Manufacturing of foamable polystyrene resin particles>
In a 6L autoclave attached to the stirrer, 167 parts by weight of pure water, 1.2 parts by weight of tricalcium phosphate, 0.022 parts by weight of α-olefin sulphonate, 0.2 parts by weight of sodium chloride, t-butylperoxy. After charging 0.04 parts by weight of -2-ethylhexyl monocarbonate (10-hour half-life temperature 99 ° C.) and 20 parts by weight of styrene-based resin seed particles having a particle size of 0.4 to 0.5 mm, stirring was started. Subsequently, after the temperature was raised to 90 ° C., 0.22 parts by weight of a benzoyl peroxide 30% solution was charged in a reactor for 5 hours and 78.0 parts by weight of a styrene monomer was charged in a reactor for polymerization. did. At this time, the methacryloyl-containing polysiloxane (methacryloyloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) 2.0 at the end of the addition of the styrene monomer (5 hours after raising the temperature at 90 ° C.) A parts by weight and 0.10 parts by weight of di-t-butylperoxyhexahydroterephthalate were charged over 4 hours and kept at 90 ° C. for 30 minutes. Then, the temperature was raised to 120 ° C. and held for 1 hour, then cooled to 98 ° C. to charge 1.0 part by weight of cyclohexane, 6.5 parts by weight of normal rich butane (70% normal butane, 30% isobutane), and 110 parts by weight. The temperature was raised to ° C. and held for 1.5 hours, and then cooled to 40 ° C. The suspension was taken out, dehydrated, dried and classified to obtain effervescent polystyrene resin particles having a particle size of 0.6 to 1.15 mm.

The obtained effervescent polystyrene-based resin particles are sieved to obtain effervescent polystyrene-based resin particles having a particle diameter of 0.5 to 1.0 mm, and further, using a pressurized pre-foaming machine "BHP-300 (manufactured by Daikai Kogyo)" Pre-foamed particles were obtained with a bulk ratio of 45 times. After curing the obtained prefoamed particles at room temperature for one day, a foamed molded product was obtained with a mold having a size of 300 × 450 × 25 (t) mm using a molding machine “KR-57 (manufactured by Daisen)”. , The surface properties of the molded product, the coefficient of static friction, and the rubbing noise were evaluated. The evaluation results are shown in Table 1.

(Examples 2 to 14, Comparative Examples 1 to 5, Comparative Examples 8 to 10)
As shown in Tables 1 and 2, foaming is performed in the same manner as in Example 1 except that the type, amount, addition time, addition time, type and amount of the addition initiator are changed. Sexual polystyrene-based resin particles, pre-foamed particles, and foamed molded product were obtained, and the same evaluation was carried out.

(Example 15)
In a 6L autoclave attached to the stirrer, 167 parts by weight of pure water, 1.2 parts by weight of tricalcium phosphate, 0.022 parts by weight of α-olefin sulphonate, 0.2 parts by weight of sodium chloride, t-butylperoxy. After charging 0.04 parts by weight of -2-ethylhexyl monocarbonate (10-hour half-life temperature 99 ° C.) and 20 parts by weight of styrene-based resin seed particles having a particle size of 0.4 to 0.5 mm, stirring was started. Next, 3.0 parts by weight of Pyroguard SR-130 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 0.6 parts by weight of dicumyl peroxide were dissolved in 10 parts by weight of styrene as flame retardants, and then added to the suspension. .. Then, after holding at 60 ° C. for 1 hour, 0.03 part by weight of a 30% benzoyl peroxide solution was added, the temperature was raised to 90 ° C., and the mixture was held for 1 hour and 30 minutes. Subsequently, 0.2 parts by weight of a 30% benzoyl peroxide solution was charged in a reactor for 4 hours and 30 minutes, and 68 parts by weight of a styrene monomer was charged in a reactor for polymerization. At this time, the methacryloyl-containing polysiloxane (methacryloyloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) 2 at the end of the addition of the styrene monomer (4 hours and 20 minutes after raising the temperature at 90 ° C.) 2 0.0 part by weight and 0.1 part by weight of di-t-butylperoxyhexahydroterephthalate were charged over 2 hours and maintained at 90 ° C. for 30 minutes. Subsequent operations were the same as in Example 1, and the evaluation results are shown in Table 1.

(Example 16)
96 parts by weight of water, 0.17 parts by weight of tricalcium phosphate, 0.048 parts by weight of sodium α-olefin sulphonate in a 6 L autoclave with a stirrer, brominated butadiene-styrene copolymer as a flame retardant (Cemtura "EMERALD 3000" Bromine content 64%) 3.0 parts by weight, 0.2 parts by weight of dicumyl peroxide as a flame retardant, 0.1 parts by weight of benzoyl peroxide as a polymerization initiator, t-butylperoxy-2-ethylhexyl mono After charging 0.37 parts by weight of carbonate and 1.4 parts by weight of coconut oil as a plasticizer, 98 parts by weight of styrene was charged and the temperature was raised to 98 ° C. to carry out polymerization. At the second hour of the polymerization, 0.10 parts by weight of the third calcium phosphate was added, and the polymerization was carried out for 5 hours. Subsequently, 2.0 parts by weight of methacryloyl-containing polysiloxane (methacryloyloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) and 0.1 parts by weight of di-t-butylperoxyhexahydroterephthalate were added. It was added over time and polymerized for an additional 30 minutes. Further, 1.0 part by weight of cyclohexane and 6.5 parts by weight of normal rich butane (70% normal butane, 30% isobutane) were charged, the temperature was raised to 120 ° C., and the foaming agent was impregnated and polymerized for 4 hours. Then, after cooling to 40 ° C., it was washed, dehydrated, and dried to obtain foamable polystyrene resin particles.

The obtained effervescent polystyrene-based resin particles are sieved to obtain effervescent polystyrene-based resin particles having a particle diameter of 0.5 to 1.0 mm, and further, using a pressurized pre-foaming machine "BHP-300 (manufactured by Daikai Kogyo)". Pre-foamed particles were obtained with a bulk ratio of 45 times. After curing the obtained prefoamed particles at room temperature for one day, a foamed molded product was obtained with a mold having a size of 300 × 450 × 25 (t) mm using a molding machine “KR-57 (manufactured by Daisen)”. , The surface properties of the molded product, the coefficient of static friction, and the rubbing noise were evaluated. The evaluation results are shown in Table 1.

(Example 17)
Instead of 78.0 parts by weight of the styrene-based monomer, 73 parts by weight of the styrene monomer and 5 parts by weight of butyl acrylate were mixed in advance, and a total of 78 parts by weight of the monomer was added over 5 hours and 30 minutes. Then, 2.0 parts by weight of the methacryloyl-containing polysiloxane and 0.1 part by weight of the dit-butylperoxyhexahydroterephthalate were charged over 2 hours, and the same procedure as in Example 1 was carried out. The evaluation results are shown in Table 1.

(Comparative Example 6)
96 parts by weight of water, 0.17 parts by weight of tricalcium phosphate, 0.048 parts by weight of sodium α-olefin sulfonate, 0.1 parts by weight of benzoyl peroxide as a polymerization initiator, t-butylperoxy in a 6 L autoclave with a stirrer. 0.37 parts by weight of 2-ethylhexyl monocarbonate, 1.4 parts by weight of coconut oil as a plasticizing agent, and polysiloxane containing methacryloyl (methacryloyloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) After charging 2.0 parts by weight and 0.1 parts by weight of di-t-butylperoxyhexahydroterephthalate, 98 parts by weight of styrene was charged and the temperature was raised to 98 ° C. for polymerization. As a result, polystyrene-based resin particles could not be obtained because the inside of the can aggregated in the first hour of polymerization and abnormal polymerization occurred.

(Comparative Example 7)
2.0 parts by weight of methacryloyl-containing polysiloxane (methacryloyloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) and 0.1 part by weight of di-t-butylperoxyhexahydroterephthalate at the initial stage of polymerization When the addition was carried out from the 1st hour to the 2nd hour of the polymerization instead of adding all at once, the inside of the can aggregated in the 2nd hour of the polymerization and abnormal polymerization occurred, so that polystyrene-based resin particles could not be obtained. ..

Claims (7)

A method for producing foamable polystyrene-based resin particles containing a copolymer composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer having a functional group, wherein the polymerization conversion rate of the styrene-based monomer is 60% or more. At 99% or less, at the same time as the initiator for generating radicals, 0.5% by weight or more and 11.0% by weight or less of the polysiloxane-containing macromonomer monomer having a functional group with respect to 100% by weight of the copolymer. , A method for producing foamable polystyrene-based resin particles, which comprises adding at a rate of 0.2% by weight / hr or more and 10.0% by weight / hr or less. A claim characterized in that the addition rate of the polysiloxane-containing macromonomer monomer having a functional group is 0.4% by weight or more and 8.0% by weight / hr or less with respect to 100% by weight of the copolymer. Item 2. The method for producing foamable polystyrene-based resin particles according to Item 1. The method for producing foamable polystyrene-based resin particles according to claim 1 or 2, wherein the initiator that generates radicals is a peroxide-based initiator. The effervescent polystyrene type according to any one of claims 1 to 3, wherein the amount of the polysiloxane-containing macromonomer monomer having a functional group added is 0.8% by weight or more and 10.2% by weight or less. Method for producing resin particles. The method for producing foamable polystyrene-based resin particles according to any one of claims 1 to 4, wherein the main component of the surface layer portion is polysiloxane. A method for producing polystyrene-based pre-foamed particles, which comprises pre-foaming the effervescent polystyrene-based resin particles according to any one of claims 1 to 5. A method for producing an effervescent molded product, which comprises molding the polystyrene-based prefoamed particles according to claim 6.