JP7001362B2 - Effervescent polystyrene resin particles, polystyrene pre-expanded particles and foam molded products - Google Patents

Description

The present invention relates to effervescent polystyrene-based resin particles whose monomer composition is composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer. Further, the present invention relates to polystyrene-based prefoamed particles and foamed molded products using the same.

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 driving on rough roads, and the generation of rubbing noise causes a deterioration in usability.

In order to solve such a problem, a foamed molded product in which an aliphatic compound or a silicone compound is coated on a 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 body composed of fatty acid amide and a foamed particle molded body composed of thermoplastic resin prefoamed particles having a monoester of saturated fatty acid and glycerin 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-based 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 prefoaming 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, as an example of copolymerizing a macromonomer with a styrene-based monomer, the preceding documents 5 to 8 are described. However, none of these methods is expected to have a rubbing noise suppression performance for 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 is an effervescent polystyrene-based material that can obtain a foamed molded product capable of suppressing rubbing noise without applying a large amount of an adhering agent and without contaminating the prefoaming machine or the molding die. The purpose is to obtain resin 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.

In the first aspect of the present invention, the monomer composition is composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer, and the polysiloxane-containing macromonomer monomer has 1.5 or more functional groups of 50.0. The present invention relates to foamable polystyrene-based resin particles, which are characterized by the following.

The second aspect of the present invention relates to the effervescent polystyrene-based resin particles according to the first aspect of the present invention, wherein the polysiloxane-containing macromonomer monomer has functional groups at both ends.

A third aspect of the present invention relates to the effervescent polystyrene-based resin particles according to the first or second invention, wherein the polysiloxane-containing macromonomer monomer has a functional group in the side chain.

A fourth aspect of the present invention relates to the effervescent polystyrene-based resin particles according to any one of the first to third inventions, wherein the polysiloxane-containing macromonomer monomer has functional groups at both ends and side chains.

Fifth of the present invention relates to the foamable polystyrene-based resin particles according to any one of the first to fourth items, wherein the functional group of the polysiloxane-containing macromonomer monomer is a vinyl group.

A sixth aspect of the present invention relates to the effervescent polystyrene-based resin particles according to any one of the first to fifth inventions, wherein the gel content insoluble in THF is 5 wt% or more and 45 wt% or less.

A seventh aspect of the present invention is the foaming according to any one of the first to sixth aspects, wherein the weight average molecular weight determined by using GPC, which is a component soluble in THF, is 200,000 or more and 400,000 or less. Sexual polystyrene-based resin particles.

In the eighth aspect of the present invention, the monomer composition is 89.0 parts by weight or more and 99.2 parts by weight or less of the styrene-based monomer, and 0.8 parts by weight or more and 11.0 parts by weight or less of the polysiloxane-containing macromonomer monomer. The foamable polystyrene-based resin particles according to any one of the first to seventh inventions, characterized in that (the total amount of the styrene-based monomer and the polysiloxane-containing macromonomer monomer is 100 parts by weight). ..

The ninth aspect of the present invention relates to the effervescent polystyrene-based resin particles according to any one of the first to eighth aspects, wherein the main component of the surface layer portion is polysiloxane.

The tenth aspect of the present invention relates to polystyrene-based prefoamed particles, which are obtained by pre-foaming the effervescent polystyrene-based resin particles according to any one of the first to ninth aspects.

The eleventh aspect of the present invention relates to a foamed molded product, which is formed by molding the polystyrene-based prefoamed particles according to the tenth aspect of the invention.

According to the present invention, foamable polystyrene-based resin particles can be obtained, which can obtain 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.

The foamable polystyrene-based resin particles of the present invention are obtained by copolymerizing styrene and a polysiloxane-containing macromonomer to have a monomer composition of a styrene-based monomer and a polysiloxane-containing macromonomer monomer, and the polysiloxane-containing macromonomer. Monomer The number of functional groups of the monomer is 1.5 or more and 50.0 or less.

The polysiloxane-containing macromonomer monomer used in the present invention preferably has functional groups at both ends. When functional groups are provided at both ends, there are few steric hindrances when the functional groups are added, and the reactivity with the styrene-based monomer is high.

The polysiloxane-containing macromonomer monomer used in the present invention preferably has a functional group in the side chain. When the side chain has a functional group, the polysiloxane main chain has a high degree of freedom when bonded to the particles, so that the coefficient of friction is lowered and the rubbing noise suppression performance is improved.

The functional group is not particularly limited as long as it is a functional group that reacts with the styrene-based monomer, but a vinyl group is preferable from the viewpoint of reactivity with the styrene-based monomer, and a methacryloyl group or an acryloyl group is more preferable.

As an example of the polysiloxane-containing macromonomer monomer, polyorganosiloxane such as polydimethylsiloxane, polymethylphenylsiloxane, and polydimethylsiloxane-diphenylsiloxane copolymer, and a part of the side chain alkyl group was replaced with a hydrogen atom. Polyorganohydrogensiloxane and the like 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 functional group is 1.5 or 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, so that it tends to be difficult to copolymerize. 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 will occur, and there is a problem that the reactivity with the styrene-based monomer is deteriorated.

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 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. The method of polymerizing 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, the polystyrene-equivalent weight average molecular weight (Mw) in a solution, slurry, or emulsion is preferably 20,000 or more, more preferably 50,000 or more, and further having a polysiloxane of 100,000 or more and preferably a functional group. Examples thereof include 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.

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 propyloxysilanes, condensates of trifunctional or higher silanes such as methyl orthosilicates, and optionally mercaptopropyldimethoxymethylsilanes, acryloyloxypropyldimethoxymethylsilanes, and methacryloyloxypropyldimethoxymethylsilanes. , Vinyldimethoxymethylsilane, Vinylphenyldimethoxymethylsilane and other functional groups can be used to obtain polysiloxane-containing macromonomers. 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, and more preferably 50 mm ² / s or more at 25 ° C. as the 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, is preferably 1,000 or more and 500,000 or less, and more preferably 3,000 or more and 300,000 or less in terms of polystyrene-equivalent weight average molecular weight obtained by using GPC. The higher the molecular weight, the longer the siloxane chain, and the more likely it is that the rubbing noise suppression performance will be exhibited. However, if the viscosity is too high, the handling property will deteriorate and polymerization will become difficult.

The gel content insoluble in THF in the present invention is 5 wt% or more and 45 wt% or less, 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 article 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.

The monomer composition of the base resin constituting the foamable polystyrene-based resin particles in the present invention is 89.0 parts by weight or more and 99.2 parts by weight or less of the styrene-based monomer, and the polysiloxane-containing macromonomer monomer 0. It is 8 parts by weight or more and 11.0 parts by weight or less (the total amount of the styrene-based monomer and the polysiloxane-containing macromonomer monomer is 100 parts by weight), and more preferably 93.0 parts by weight of the styrene-based monomer. 98.5 parts by weight or less, 1.5 parts by weight or more and 7.0 parts by weight or less of the polysiloxane-containing macromonomer monomer. 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.

As the styrene-based monomer used in the present invention, for example, styrene-based derivatives such as styrene, α-methylstyrene, paramethylstyrene, t-butylstyrene, and chlorstyrene 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 moldability.

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 acrylic acid and methacrylic acid esters 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 bifunctional 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, the total amount of styrene and other monomers is preferably 98.8 parts by weight or more and 99.0 parts by weight or less.

It is preferable that the main component of the surface layer portion of the effervescent polystyrene-based resin particles of the present invention is polysiloxane.

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, which is a state in which 50% by weight or more of the polysiloxane component is contained. It is 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, it tends to be difficult to exhibit the rubbing noise suppressing performance.

The polysiloxane-containing monomer may be added at any stage of the polymerization, but in order to allow it to be present on the surface more and to obtain the rubbing noise suppressing performance, the polysiloxane-containing simpler should be added at the end of the addition of the styrene-based monomer. It is preferable to add a monomer.

As a method for producing the effervescent resin particles of the present invention, a method of polymerizing a styrene-based monomer in an aqueous suspension, suspending the polymerization, 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, bubble regulators, flame retardant agents, 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.

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 during 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 a water-soluble polymer. More than 500 ppm is preferable.

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 for the first-stage polymerization, a radical generation type 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 peroxides, azobisisobutyronitrile, azobisdimethyl Examples include azo compounds such as valeronitrile. These polymerization initiators may be used alone or in combination of two or more.

Examples of the foaming agent include aliphatic hydrocarbons having 3 or more and 5 or less carbon atoms such as propane, isobutane, normal butane, isopentane, normal pentane, and neopentane, and ozone depletion potential 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 at all. 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 is likely 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, and examples thereof include fatty acid glycerides such as stearic acid triglyceride, palmitic acid triglyceride, laurate triglyceride, stearic acid diglyceride, and stearic acid monoglyceride, palm oil, and palm oil. 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 bisstearate 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. Among them, 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 at the time of impregnation 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- Diglycidyl ether, brominated phenol derivatives such as 2,2-bis [4'(2 ", 3" -dibromoalkoxy) -3', 5'-dibromophenyl] -propane, brominated styrene-butadiene block copolymers , Brominated 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 form 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 foam molded product.

The styrene-based foamed molded product of the present invention was pre-foamed at a foaming magnification 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.

<Measurement of gel content>
The obtained effervescent polystyrene-based resin particles were dissolved in 20 ml of tetrahydrofuran (hereinafter, may be abbreviated as "THF") in 0.25 g, and the mixture was stirred with a magnetic stirrer for 3 hours. Then, it was filtered through a weighed filter paper, and the gel component remaining on the filter paper was dried together with the filter paper at 30 ° C. for 24 hours. The gel component after drying was weighed together with the filter paper, and the gel content was calculated by the following formula.
Gel content (wt%) = (weight of filter paper after filtration-weight of filter paper before filtration) / 0.25 * 100
<GPC measurement>
For the obtained effervescent polystyrene-based resin particles, 0.02 g of effervescent polystyrene-based resin particles was dissolved in 20 ml of tetrahydrofuran (hereinafter, may be abbreviated as "THF"), 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 a GPC measurement chart and a weight average molecular weight (Mw) and a number average molecular weight (Mw) were measured. Mn) was obtained. The obtained values are relative values in terms of polystyrene.
Measuring device: Tosoh's high-speed GPC device HLC-8220
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>
Effervescent polystyrene-based resin particles classified to a predetermined particle size by a sieve are blown into a prefoaming machine "Ohiraki Kogyo, BHP" under the condition of a vapor pressure of 0.09 to 0.12 MPa to a bulk magnification of 45 times. After pre-foaming, 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 molded products>
The obtained styrene-based prefoamed particles were blown into a mold using a molding machine "Daisen, KR-57" at a vapor pressure of 0.10 MPa, and formed into a flat plate having a thickness of 25 mm and a length of 400 mm and a width of 350 mm. The foam molded product of 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 3 or more expressed on a scale of 5 was regarded as acceptable.

5: No gaps are found 4: There are some gaps, but I can hardly tell 3: There are gaps in some places, but it is acceptable as a whole 2: The gaps are conspicuous 1: There are many gaps.

<Measurement of static friction coefficient>
A single-sided skin test piece 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. After that, 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 same environment 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 the 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 obtained in the range of 5000 or more and 20,000 Hz or less, which humans feel uncomfortable.

<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 combustion test.
Combustion rates were evaluated using the resulting test pieces in a manner compliant with US Automotive 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 10,000 :, viscosity: 200 mm ² / s, number of functional groups: 0.8, functional group equivalent: 12000 g / mol) (manufactured by Shinetsu Silicone Co., Ltd.) ..

(Example 1)
<Manufacturing of polystyrene-based resin seed particles>
In a reactor equipped with a stirrer, 100 parts by weight of pure water, 0.4 parts by weight of tertiary calcium phosphate, 0.01 parts by weight of sodium dodecylbenzene sulfonate, 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 the temperature 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 effervescent polystyrene resin particles>
In a 6L autoclave attached to the stirrer, 167 parts by weight of pure water, 1.2 parts by weight of tertiary calcium phosphate, 0.022 parts by weight of α-olefin sulphonate soda, 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 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 79.5 parts by weight of a styrene monomer was charged in a reactor for polymerization. did. At this time, at the end of the addition of the styrene monomer (5 hours after the temperature rise to 90 ° C.), the methacryloyl-containing polysiloxane (methacryloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) 0.5. A parts by weight and 0.025 parts by weight of di-t-butylperoxyhexahydroterephthalate were charged over 30 minutes and maintained 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 were sieved to obtain effervescent polystyrene-based resin particles having a particle diameter of 0.5 to 1.0 mm, and further subjected to a pressurized pre-foaming machine "BHP-300 (manufactured by Daikai Kogyo)". Pre-foamed particles were obtained with a bulk ratio of 45 times. After the obtained preliminary foamed particles were cured at room temperature for one day, a foamed molded product was obtained in 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 9, Comparative Examples 1 to 5)
As shown in Table 1, the foamable polystyrene resin particles and the pre-expanded particles were prepared in the same manner as in Example 1 except that the type, amount, addition time and amount of the addition initiator were changed. A foam molded product was obtained and the same evaluation was performed.

(Example 10)
In a 6L autoclave attached to the stirrer, 167 parts by weight of pure water, 1.2 parts by weight of tertiary calcium phosphate, 0.022 parts by weight of α-olefin sulphonate soda, 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 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 the reactor for 4 hours and 30 minutes, and 68 parts by weight of the styrene monomer was charged in the reactor for polymerization. At this time, at the end of the addition of the styrene monomer (4 hours and 20 minutes after the temperature rise at 90 ° C.), the methacryloyl-containing polysiloxane (methacryloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) 2 0.0 parts 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 11)
96 parts by weight of water, 0.17 parts by weight of tertiary calcium phosphate, 0.048 parts by weight of α-olefin sulfonate, brominated butadiene-styrene copolymer as flame retardant (EMERALD 3000 manufactured by Chemtura) in a 6 L autoclave with a stirrer. 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-ethylhexylmono 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, the temperature was raised to 98 ° C., and polymerization was carried out for 5 hours. Subsequently, 2 parts by weight of methacryloyl-containing polysiloxane (methacryloxypropyldimethoxymethylsilane content: 2.5% by weight, molecular weight: 200,000) and 0.1 part by weight of di-t-butylperoxyhexahydroterephthalate over 2 hours. Was added, and the mixture was further polymerized for 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 and heated to 120 ° C., and impregnated with a foaming agent and polymerized for 4 hours. Then, after cooling to 40 degreeC, it was washed, dehydrated, and dried to obtain effervescent polystyrene resin particles.

The obtained effervescent polystyrene-based resin particles were sieved to obtain effervescent polystyrene-based resin particles having a particle diameter of 0.5 to 1.0 mm, and further subjected to a pressurized pre-foaming machine "BHP-300 (manufactured by Daikai Kogyo)". Pre-foamed particles were obtained with a bulk ratio of 45 times. After the obtained preliminary foamed particles were cured at room temperature for one day, a foamed molded product was obtained in 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 12)
Instead of 79.5 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. The same procedure as in Example 1 was carried out except that 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. The evaluation results are shown in Table 1.

Claims (10)

The monomer composition is composed of a styrene-based monomer and a polysiloxane-containing macromonomer monomer, and the polysiloxane-containing macromonomer monomer has 1.5 or more and 50.0 or less functional groups.
The functional group of the polysiloxane-containing macromonomer monomer is a vinyl group,
Effervescent polystyrene-based characterized in that the amount of the polysiloxane-containing macromonomer is 0.5 parts by weight or more (the total amount of the styrene-based monomer and the polysiloxane-containing macromonomer monomer is 100 parts by weight) . Resin particles. The foamable polystyrene-based resin particle according to claim 1, wherein the polysiloxane-containing macromonomer monomer has functional groups at both ends. The effervescent polystyrene-based resin particles according to claim 1 or 2, wherein the polysiloxane-containing macromonomer monomer has a functional group in the side chain. The foamable polystyrene-based resin particle according to any one of claims 1 to 3, wherein the polysiloxane-containing macromonomer monomer has functional groups at both ends and side chains. The foamable polystyrene-based resin particle according to any one of claims 1 to 4, wherein the gel content insoluble in THF is 5 wt% or more and 45 wt% or less. The effervescent polystyrene-based resin particles according to any one of claims 1 to 5, wherein the weight average molecular weight determined by using GPC, which is a component soluble in THF, is 200,000 or more and 400,000 or less. The monomer composition is 89.0 parts by weight or more and 99.2 parts by weight or less of the styrene-based monomer, and 0.8 parts by weight or more and 11.0 parts by weight or less of the polysiloxane-containing macromonomer monomer (with the styrene-based monomer). The foamable polystyrene-based resin particle according to any one of claims 1 to 6, wherein the total amount of the polysiloxane-containing macromonomer monomer is 100 parts by weight). The effervescent polystyrene-based resin particles according to any one of claims 1 to 7, wherein the main component of the surface layer portion is polysiloxane. The polystyrene-based pre-expanded particles, which are obtained by pre-foaming the effervescent polystyrene-based resin particles according to any one of claims 1 to 8. A foamed molded product obtained by molding the polystyrene-based prefoamed particles according to claim 9.