JP6322148B2 - Seed polymerization seed particles, composite resin particles, expandable particles, expanded particles, and composite resin foam moldings - Google Patents

Description

  The present invention relates to seed particles for seed polymerization, composite resin particles, expandable particles, expanded particles, and a composite resin foam molded article. More specifically, the present invention relates to a composite resin particle capable of providing a composite resin foam molded article having excellent heat resistance while maintaining good moldability, a seed for producing foamable particles and foamed particles by a seed polymerization method. The present invention relates to a seed particle for polymerization, a composite resin particle, an expandable particle, an expanded particle, and a composite resin foam molded body obtained therefrom.

Foamed molded articles made of polystyrene resin are widely used as packaging materials and heat insulating materials because they have excellent buffering properties and heat insulating properties and are easy to mold. However, since the impact resistance and flexibility are insufficient, cracks and chips are likely to occur, and it is not suitable, for example, for packaging precision instrument products.
On the other hand, a foam-molded article made of polyolefin resin is excellent in impact resistance and flexibility, but requires a large facility for molding. Also, due to the nature of the resin, it must be transported from the raw material manufacturer to the molding processing manufacturer in the form of pre-expanded particles. Therefore, bulky pre-expanded particles are transported, and there is a problem that the manufacturing cost increases.
Therefore, various polystyrene composite resin particles having the characteristics of the above two different resins and composite resin foam molded articles using them have been proposed.

For example, Japanese Patent No. 4718597 (Patent Document 1) has a polypropylene resin and a polystyrene resin having a melting point of 140 ° C. to 145 ° C. obtained by a seed polymerization method under specific conditions, and 100 mass of polypropylene resin. A sea-island structure containing polystyrene resin in an amount of 30 parts by mass or more and less than 600 parts by mass and having a polystyrene resin particle having a particle major axis of 5 μm or less dispersed in a polypropylene resin. Styrene-modified polypropylene resin particles, foamable styrene-modified polypropylene resin particles impregnated with a foaming agent, styrene-modified polypropylene resin foam particles pre-foamed, and filled into a mold and foamed A molded styrene-modified polypropylene resin foam molded article having a specific density is disclosed.
Patent Document 1 describes a styrene-modified polypropylene resin foam molded article that has improved mechanical properties and chemical resistance by improving the disadvantages of both a foam molded article made of polystyrene resin and a foam molded article made of polypropylene resin. This object is achieved by the above configuration.

Japanese Patent No. 4718597

The foam molded article of Patent Document 1 improves the problems of chemical resistance and impact resistance of a foam molded article made of a polystyrene resin and the moldability of a foam molded article made of a polypropylene resin. High heat resistance under time conditions.
However, in recent years, foam molded articles used in high-temperature environments, particularly automobile members, have been required to have heat resistance under more severe conditions (high temperature and long time).

  Accordingly, the present invention provides polymer particles, expandable particles, and expanded particles that can provide a composite resin expanded molded article having heat resistance even better than conventional expanded molded articles while maintaining good moldability. It is an object of the present invention to provide seed particles for seed polymerization for production by a polymerization method, polymer particles obtained from the seed particles, expandable particles, expanded particles, and a composite resin foam molded article.

As a result of intensive studies to solve the above problems, the inventors of the present invention have modified polypropylene resins used for seed polymerization with engineering plastics such as polycarbonate resins, polyamide resins, and polyphenylene ether resins. It has been found that there is an effect of improving heat resistance, and among these, the effects of polyamide resins and polyphenylene ether resins are particularly high, and even when added in a small amount, the present invention has been completed.
The prior art related to a composite resin of a polyolefin resin such as a polypropylene resin and a polystyrene resin, and the prior art using the above engineering plastic as a modified resin are often seen, but the engineering plastic such as the present invention was modified. There is no prior art relating to seed particles for seed polymerization made of polyolefin resin and composite resin particles subjected to seed polymerization using the seed particles.

Thus, according to the present invention, in addition to a polypropylene resin and a polystyrene resin, a composite resin foamed molded article containing at least one modified resin component selected from a polycarbonate resin, a polyamide resin, and a polyphenylene ether resin ( Hereinafter, it is also simply referred to as “foam molded article”.
Absorbance ratio (D698 / D1376) of the absorbance at 698 cm ⁻¹ derived from polystyrene resin (D698) and the absorbance at 1376 cm ⁻¹ derived from polypropylene resin (D1376) obtained from the infrared absorption spectrum inside the composite resin foam molded article. ) Is 2 to 30 times the absorbance ratio (D698 / D1376) obtained from the infrared absorption spectrum of the skin surface of the composite resin foam molded article, a composite resin foam molded article is provided.

Further, according to the present invention, seed polymer seed particles for obtaining composite resin particles for obtaining the above composite resin foam molded article by foam molding,
The seed particles for seed polymerization comprise a polypropylene resin and at least one modified resin component selected from a polycarbonate resin, a polyamide resin, and a polyphenylene ether resin at a mass ratio of 99/1 to 80/20. A seed particle for seed polymerization is provided.

Furthermore, according to the present invention, composite resin particles obtained by subjecting the seed polymerization seed particles and the styrene monomer to a seed polymerization method are provided.
Furthermore, according to the present invention, there are provided expandable particles obtained by impregnating the composite resin particles with a foaming agent.
The present invention also provides expanded particles obtained by pre-expanding the expandable particles.

  According to the present invention, polymer particles, expandable particles, and expanded particles that can provide a composite resin expanded molded article having heat resistance further superior to conventional expanded molded articles while maintaining good moldability are seeded. It is possible to provide seed particles for seed polymerization for production by a polymerization method, polymer particles obtained from the seed particles, expandable particles, expanded particles, and composite resin foam molded articles.

The composite resin foam molded article of the present invention is
(1) A composite resin obtained by subjecting seed polymerization seed particles containing a polypropylene resin and a modified resin component in a mass ratio of 99/1 to 80/20 and a styrene monomer to a seed polymerization method. (2) Polypropylene resin has a melting point of 125 to 165 ° C, and polycarbonate resin, polyamide resin and polyphenylene ether resin have a melting point of 145 to 180 ° C. When the glass transition point or the melting point of 190 ° C. to 240 ° C. and (3) the modified resin component satisfies at least one condition of a polyamide resin, a polyphenylene ether resin or a combination thereof, The excellent effect of is further demonstrated.

  In the seed particles for seed polymerization of the present invention, the polypropylene resin has a melting point of 125 to 165 ° C, and the polycarbonate resin, the polyamide resin, and the polyphenylene ether resin have a glass transition point of 190 to 180 ° C or 190. In the case of having a melting point of from ° C to 240 ° C, the above excellent effect is further exhibited.

It is a schematic diagram for demonstrating the measuring method of the light absorbency ratio of a foaming molding.

  The present invention provides composite resin particles capable of providing a foamed molded article having excellent heat resistance while maintaining good moldability, seedable particles for seed polymerization for producing foamable particles and foamed particles by a seed polymerization method, and The composite resin particles, foamable particles, foamed particles and foamed molded product obtained will be described below in this order.

(1) Seed particles for seed polymerization The seed particles for seed polymerization (hereinafter also referred to as “seed particles”) of the present invention are at least one selected from a polypropylene resin, a polycarbonate resin, a polyamide resin, and a polyphenylene ether resin. It contains a modified resin component of seeds at a mass ratio of 99/1 to 80/20.
The seed particles for seed polymerization of the present invention are preferable as seed particles for seed polymerization for obtaining composite resin particles obtained by foam molding of a foam molded body to be described later.

[Polypropylene resin: PP]
The polypropylene resin used in the present invention includes a resin obtained by a known polymerization method, which may be cross-linked, and is selected from polyethylene resin and ethylene acrylic copolymer resin from the viewpoint of impact resistance. Ingredients may be included. For example, propylene, ethylene-propylene random copolymer, propylene-1-butene copolymer, ethylene-propylene-butene random copolymer and the like can be mentioned. Specifically, commercially available products as used in the examples. Is mentioned.
In the present invention, one of the above polypropylene resins can be used alone or in combination of two or more.

[Modified resin component]
(Polycarbonate resin: PC)
The polycarbonate resin used in the present invention is a known polymerization method, that is, a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. The obtained resin is mentioned.
The polycarbonate-based resin is preferably an aromatic polycarbonate-based resin having a diphenylalkane in the molecular chain in that it has a high melting point and is excellent in heat resistance, weather resistance and acid resistance.
Examples of the polycarbonate resin used in the present invention include 2,2-bis (4-oxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-oxyphenyl) butane, 1,1-bis ( 4-oxyphenyl) cyclohexane, 1,1-bis (4-oxyphenyl) isobutane, polycarbonate resins derived from bisphenols such as 1,1-bis (4-oxyphenyl) ethane, and the like. Commercial products such as those used in the examples can be mentioned.
In the present invention, one of the above polycarbonate resins can be used alone or in combination of two or more.

(Polyamide resin: PA)
Examples of the polyamide-based resin used in the present invention include resins obtained by known polymerization methods. Depending on the number of carbons of lactam, the number of carbons of aminocarboxylic acid, the number of carbons of diamine and dicarboxylic acid, It is called nylon 6, nylon 6, 6 or the like. For example, nylon 6 is a polyamide-based resin obtained by ring-opening polymerization of ε-caprolactam, and nylon 6,6 is a polyamide-based resin obtained by polycondensation of hexamethylenediamine and adipic acid.
Examples of the polyamide resin used in the present invention include nylon 6, nylon 6,6, nylon 10, nylon 11, nylon 12, nylon 6,12, nylon 12,12, nylon 4,6 and the like. Specifically, commercially available products such as those used in the examples can be mentioned.
In the present invention, one of the above polyamide resins can be used alone or in combination of two or more.

(Polyphenylene ether resin: PPE)
Examples of the polyphenylene ether resin used in the present invention include a resin obtained by a known polymerization method, for example, an oxidative coupling reaction of 2,6-xylenol.
Examples of the polyphenylene ether resin used in the present invention include poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), poly (2, 6-dichlorophenylene-1,4-ether) and the like, and specifically, commercially available products such as those used in the examples can be mentioned.
In the present invention, one of the above polyphenylene ether resins can be used alone or in combination of two or more.

  Among the above modified resin components, polyamide resin, polyphenylene ether resin, and those resins are used in terms of the heat resistance improvement effect of the foam molded body produced through seed particles, composite resin particles, expandable particles, and expanded particles. Combinations are particularly preferred.

[Melting point of polypropylene resin: mp]
The polypropylene resin used in the present invention preferably has a melting point of 125 to 165 ° C.
The melting point is measured by analysis with a differential scanning calorimeter (DSC), and the details thereof will be described in Examples.
When the melting point of the polypropylene resin is less than 125 ° C., the heat resistance of the foamed molded product may be insufficient. On the other hand, when the melting point of the polypropylene-based resin exceeds 165 ° C., the foaming power of the foamable composite resin particles becomes low, and a low-density foam molded article cannot be produced, and the lightening effect may not be sufficiently exhibited.
The melting point of the polypropylene resin is, for example, 125 ° C, 126 ° C, 127 ° C, 128 ° C, 129 ° C, 130 ° C, 131 ° C, 132 ° C, 133 ° C, 134 ° C, 135 ° C, 136 ° C, 136 ° C, 137 ° C, 138 ° C. 139 ° C, 140 ° C, 141 ° C, 142 ° C, 143 ° C, 144 ° C, 145 ° C, 146 ° C, 147 ° C, 148 ° C, 149 ° C, 150 ° C, 151 ° C, 152 ° C, 153 ° C, 154 ° C, 155 156 ° C., 157 ° C., 158 ° C., 159 ° C., 160 ° C., 161 ° C., 162 ° C., 163 ° C., 164 ° C., and 165 ° C.
The melting point of the polypropylene resin is more preferably 130 to 145 ° C.

[Glass transition point of modified resin component: Tg and melting point: Tm]
The resin of the modified resin component used in the present invention preferably has a glass transition point of 145 to 180 ° C or a melting point of 190 to 240 ° C.
The measurement of the glass transition point and the melting point will be described in detail in the Examples by analysis with a differential scanning calorimeter (DSC).
A resin having a glass transition point of the modified resin component of less than 145 ° C. and a melting point of less than 190 ° C. or not observed may not sufficiently exhibit the heat resistance improvement effect due to the modification of the polypropylene resin. Further, in the case of a resin having a glass transition point of less than 145 ° C. and a melting point of more than 240 ° C., the foam moldability may be remarkably lowered due to the progress of crystallization of the modified resin, while the glass transition of the modified resin component Resins having a point exceeding 180 ° C. and a melting point exceeding 240 ° C. or not observed may have excessively high heat resistance, requiring extremely high-pressure steam during foam molding and reducing productivity.

The glass transition point of the modified resin component is, for example, 145 ° C., 146 ° C., 147 ° C., 148 ° C., 149 ° C., 150 ° C., 151 ° C., 152 ° C., 153 ° C., 154 ° C., 155 ° C., 156 ° C., 157 ° C. 158 ° C, 159 ° C, 160 ° C, 161 ° C, 162 ° C, 163 ° C, 164 ° C, 165 ° C, 166 ° C, 167 ° C, 168 ° C, 169 ° C, 170 ° C, 171 ° C, 172 ° C, 173 ° C, 174 ° C ° C, 175 ° C, 176 ° C, 177 ° C, 178 ° C, 179 ° C, 180 ° C.
A more preferable glass transition point of the modified resin component is 150 to 175 ° C.

The melting point of the modified resin component is, for example, 190 ° C., 191 ° C., 192 ° C., 193 ° C., 194 ° C., 195 ° C., 196 ° C., 197 ° C., 198 ° C., 199 ° C., 200 ° C., 201 ° C., 202 ° C., 203 , 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236 237 ° C, 238 ° C, 239 ° C, 240 ° C.
A more preferable melting point of the modified resin component is 210 to 230 ° C.

[Relationship between melting point of polypropylene resin and glass transition point and melting point of modified resin component]
In the present invention, when the melting point of the polypropylene resin is PP (Tm), the glass transition point of the modified resin component is Re (Tg), and the melting point of the modified resin component is Re (Tm), the following relationship is satisfied. In some cases, the effect of improving the heat resistance is exhibited, and when it is not satisfied, the effect of improving the heat resistance may not be sufficiently obtained.
PP (Tm) <Re (Tg) or Re (Tg) <PP (Tm) <Re (Tm)

[Mass ratio of polypropylene resin to modified resin component]
The seed particles of the present invention contain a polypropylene resin and a modified resin component in a mass ratio of 99/1 to 80/20.
If the mass ratio of the seed particles exceeds 99/1, that is, the polypropylene resin becomes excessive and the modified resin component becomes insufficient, the resin modification by the modified resin component becomes insufficient, and the sufficient heat resistance of the present invention is achieved. The effect of improving the properties may not be obtained. On the other hand, when the mass ratio of the seed particles is less than 80/20, that is, when the polypropylene resin becomes too small and the modified resin component becomes excessive, composite resin particles are produced using this, and the foamed particles and foamed particles are passed through. The foamability and fusion rate of the produced foamed molded product may be reduced, and the productivity may be reduced.
In addition, when using 2 or more types of resin as a modified resin component, those total amounts are used for said ratio.

The mass ratio of the seed particles for polymerization is, for example, 99/1, 98/2, 97/3, 96/4, 95/5, 94/6, 93/7, 92/8, 91/9, 90/10. 89/11, 88/12, 87/13, 86/14, 85/15, 84/16, 83/17, 82/18, 81/19, 80/20.
The mass ratio of the seed particles is preferably 99/1 to 90/10, more preferably 99/1 to 95/5.

[Manufacture of seed particles for seed polymerization]
The seed particles of the present invention can be obtained, for example, by melt-kneading the polypropylene resin and the modified resin component with an extruder, extruding them into a strand shape, and cutting them with a desired particle diameter.

As for the die for obtaining seed particles of a predetermined size, the diameter of the resin discharge hole is preferably 0.2 to 1.0 mm, and the land length of the resin flow path is to maintain the high dispersibility of the polystyrene resin. The resin temperature at the die inlet of the resin extruded from the extruder is adjusted to 200 to 270 ° C. so that the pressure at the die resin flow path inlet can be maintained at 10 to 20 MPa. Is preferred.
Desired seed particles can be obtained by combining an extruder and a die having the screw structure, extrusion conditions, and underwater cutting conditions.
The seed particles can contain additives such as a compatibilizing agent for polyolefin resins and polystyrene resins, a bubble adjusting agent, and an antistatic agent as long as the effects of the present invention are not impaired.

(Particle size)
The particle diameter of the seed particles can be adjusted as appropriate according to the average particle diameter of the composite resin particles, and the preferable particle diameter is in the range of 0.4 to 1.5 mm, more preferably 0.4 to 1.0 mm. The average mass is 30 to 90 mg / 100 grains. In addition, examples of the shape include a true spherical shape, an elliptical spherical shape (egg shape), a cylindrical shape, and a prismatic shape.

(2) Composite resin particles The composite resin particles of the present invention can be obtained by subjecting the above seed particles and a styrene monomer to a seed polymerization method.

(Seed polymerization)
In the seed polymerization method, the composite resin particles can be generally obtained by allowing the seed particles to absorb the monomer and polymerizing the monomer after or while absorbing the monomer. Alternatively, the foamed particles can be obtained by impregnating the composite resin particles with a foaming agent after polymerization or while polymerizing.

Specifically, first, in the aqueous medium, the above-mentioned seed particles are allowed to absorb the styrene monomer, and after the absorption or absorption, the composite resin particles are obtained by polymerizing the styrene monomer. obtain.
The styrenic monomer does not need to be supplied to the aqueous medium at the same time, and all or part of the monomer may be supplied to the aqueous medium at different timings. When the additive is included in the composite resin particles, the additive may be added to the styrene monomer or the aqueous medium, or may be included in the seed particles.
The amount of monomer and resin is almost the same.

The polymerization of the styrene monomer can be performed, for example, by heating at 60 to 150 ° C. for 2 to 40 hours.
In the polymerization step, it is preferable to hold at a polymerization temperature or higher than the polymerization temperature for a long time, that is, to anneal.
In the previous steps up to the annealing step, the styrene monomer and polymerization initiator absorbed in the seed particles have not completely completed the reaction, and there are not a few unreacted substances in the composite resin particles. doing. Therefore, when a foamed molded product is obtained using composite resin particles obtained without annealing, the mechanical properties and heat resistance of the foamed molded product are degraded due to the influence of low molecular weight unreacted materials such as styrene monomers. And odor caused by volatile unreacted materials becomes a problem. Therefore, by introducing an annealing step, it is possible to secure a time for the unreacted material to undergo a polymerization reaction, and to remove the remaining unreacted material so as not to affect the physical properties of the foam molded article.

(Polystyrene resin)
The polystyrene resin obtained by seed polymerization is not particularly limited as long as it is a resin mainly composed of a styrene monomer used in the technical field, and includes a styrene or a styrene derivative alone or a copolymer.
Examples of the styrene derivative include α-methyl styrene, vinyl toluene, chlorostyrene, ethyl styrene, isopropyl styrene, dimethyl styrene, bromostyrene, and the like. These styrenic monomers may be used alone or in combination.

The polystyrene resin may be a combination of a vinyl monomer copolymerizable with a styrene monomer.
Examples of the vinyl monomer include divinylbenzene such as o-divinylbenzene, m-divinylbenzene and p-divinylbenzene, alkylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate. And polyfunctional monomers such as (meth) acrylate; (meth) acrylonitrile, methyl (meth) acrylate, butyl (meth) acrylate and the like. Among these, polyfunctional monomers are preferable, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate having 4 to 16 ethylene units, and divinylbenzene are more preferable, and divinylbenzene, ethylene glycol di ( Particularly preferred is (meth) acrylate. In addition, a monomer may be used independently or may be used together.
Moreover, when using a monomer together, it is preferable that the content is set so that it may become the quantity (for example, 50 mass% or more) which a styrene-type monomer becomes a main component.
In the present invention, “(meth) acryl” means “acryl” or “methacryl”.

The composite resin particles of the present invention preferably contain a polystyrene resin and seed particles in a mass ratio of 90/10 to 50/50.
If the mass ratio of the composite resin particles exceeds 90/10, that is, the polystyrene resin becomes excessive and the seed particles become excessive, the chemical resistance and impact resistance of the foamed molded product may be insufficient. Heat resistance may decrease. On the other hand, when the mass ratio of the composite resin particles is less than 50/50, that is, when the polystyrene-based resin becomes excessive and the seed particles become excessive, the foam moldability may be lowered.
The mass ratio of the composite resin particles is, for example, 90/10, 88/12, 85/15, 80/20, 78/22, 75/25, 70/30, 65/35, 62/38, 60/40, 58/42, 55/45, and 50/50.
A more preferable mass ratio of the composite resin particles is 70/30 to 55/45.

(Aqueous medium)
Examples of the aqueous medium include water and a mixed medium of water and a water-soluble solvent (for example, a lower alcohol such as methyl alcohol or ethyl alcohol).

(Dispersant)
In the aqueous medium, a dispersant may be used in order to stabilize the dispersibility of the styrene monomer droplets and seed particles. Examples of such a dispersant include organic dispersants such as partially saponified polyvinyl alcohol, polyacrylate, polyvinyl pyrrolidone, carboxymethyl cellulose, and methyl cellulose; magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, calcium carbonate, magnesium phosphate, Examples thereof include inorganic dispersants such as magnesium carbonate and magnesium oxide. Among these, an inorganic dispersant is preferable because a more stable dispersion state may be maintained.
When an inorganic dispersant is used, it is preferable to use a surfactant in combination. Examples of such surfactants include sodium dodecylbenzene sulfonate and sodium α-olefin sulfonate.

(Polymerization initiator)
Styrene monomers are usually polymerized in the presence of a polymerization initiator. The polymerization initiator is usually impregnated into the seed particles simultaneously with the styrene monomer.
The polymerization initiator is not particularly limited as long as it is conventionally used for the polymerization of styrene monomers. For example, benzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxyisopropyl carbonate, t-butyl peroxyacetate, 2, 2-t-butylperoxybutane, t-butylperoxy-3,3,5-trimethylhexanoate, di-t-butylperoxyhexahydroterephthalate, 2,5-dimethyl-2,5-bis (benzoyl) Organic peroxides such as peroxy) hexane and dicumyl peroxide. These polymerization initiators may be used alone or in combination of two or more. The usage-amount of a polymerization initiator is the range of 0.1-5 mass parts with respect to 100 mass parts of styrene-type monomers, for example.

  In order to uniformly absorb the polymerization initiator from the seed particles or the seed particles to the growing particles, the polymerization initiator is suspended or emulsified and dispersed in advance in the aqueous medium when the polymerization initiator is added to the aqueous medium. It is preferable to add to the dispersion liquid above, or to add the polymerization initiator to the aqueous medium after previously dissolving it in the styrene monomer.

The addition amount of a polymerization initiator is 0.1-0.9 mass part per 100 mass parts of styrene-type monomers.
When the addition amount of the polymerization initiator is less than 0.1 part by mass, the molecular weight becomes too high and foamability may be lowered. On the other hand, when the addition amount of the polymerization initiator exceeds 0.9 parts by mass, the polymerization rate may become too fast, and the dispersion state of the polystyrene resin particles in the polyolefin resin may not be controlled. A preferable addition amount of the polymerization initiator is 0.2 to 0.5 parts by mass.

(Other ingredients)
The composite resin particles have a colorant, a flame retardant, a flame retardant aid, a plasticizer, a binding inhibitor, a cell regulator, a cross-linking agent, a filler, a lubricant, and a fusion promoter within a range that does not impair the physical properties. Additives such as antistatic agents and spreading agents may be added.

Examples of the colorant include furnace black, ketjen black, channel black, thermal black, acetylene black, graphite, carbon fiber, and other carbon black, and may be a masterbatch blended in a resin.
The carbon black content of the preferred composite resin particles is 1.5 to 5.0% by mass.

Examples of the flame retardant include tri (2,3-dibromopropyl) isocyanate, bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] sulfone, tetrabromocyclooctane, hexabromocyclododecane, and trisdibromo. Examples thereof include propyl phosphate, tetrabromobisphenol A, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol A-bis (2,3-dibromopropyl ether), and the like.
Examples of the flame retardant aid include organic peroxides such as 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, dicumyl peroxide, and cumene hydroperoxide. It is done.
The content of the flame retardant and flame retardant aid in the preferred composite resin particles is 1.0 to 5.0 mass% and 0.1 to 2.0 mass%, respectively.

Examples of the plasticizer include glycerin fatty acid esters such as phthalic acid esters, glycerin diacetomonolaurate, glycerin tristearate, and glycerin diacetomonostearate, adipic acid esters such as diisobutyl adipate, and plasticizers such as coconut oil. .
The content of the plasticizer of the preferable composite resin particle is 0.1 to 3.0% by mass.

Examples of the binding inhibitor include calcium carbonate, silica, zinc stearate, aluminum hydroxide, ethylene bis stearamide, tricalcium phosphate, dimethyl silicon and the like.
Examples of the air conditioner include ethylene bis stearamide, polyethylene wax and the like.
As a crosslinking agent, 2,2-di-t-butylperoxybutane, 2,2-bis (t-butylperoxy) butane, dicumyl peroxide, 2,5-dimethyl-2,5-di-t -Organic peroxides such as butylperoxyhexane.
Examples of the filler include silicon dioxide produced synthetically or naturally.

Examples of the lubricant include paraffin wax and zinc stearate.
Examples of the fusion accelerator include stearic acid, stearic acid triglyceride, hydroxystearic acid triglyceride, stearic acid sorbitan ester, and polyethylene wax.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether, stearic acid monoglyceride, polyethylene glycol and the like.
Examples of the spreading agent include polybutene, polyethylene glycol, and silicone oil.

(Average particle size)
The composite resin particles preferably have an average particle diameter of 0.5 to 2.0 mm.
When the average particle diameter of the composite resin particles is less than 0.5 mm, high foamability may not be obtained. On the other hand, when the average particle diameter of the composite resin particles exceeds 2.0 mm, the pre-expanded particles may not be sufficiently filled during the molding process. More preferably, the average particle diameter of the composite resin particles is 0.8 to 1.5 mm.

(3) Expandable particles The expandable particles of the present invention are obtained by impregnating the composite resin particles of the present invention with a foaming agent by a known method.
When the temperature at which the composite resin particles are impregnated with the foaming agent is low, it takes time for the impregnation, and the production efficiency of the expandable particles may be reduced. On the other hand, when the temperature is high, the coalescence between the expandable particles is large. Since it may generate | occur | produce, 50-130 degreeC is preferable and 60-100 degreeC is more preferable.

(Foaming agent)
The foaming agent is preferably a volatile foaming agent and is not particularly limited as long as it is conventionally used for foaming polystyrene resins. For example, carbon such as isobutane, n-butane, isopentane, n-pentane, neopentane, etc. Examples include volatile foaming agents such as aliphatic hydrocarbons having a number of 5 or less, and butane-based foaming agents and pentane-based foaming agents are particularly preferable. In addition, pentane can be expected to act as a plasticizer.

The content of the foaming agent in the expandable particles is usually in the range of 2 to 10 mass%, preferably in the range of 3 to 10 mass%, particularly preferably in the range of 3 to 8 mass%.
When the content of the foaming agent is small, for example, less than 2% by mass, it may not be possible to obtain a low-density foam molded product from the foamable particles, and the effect of increasing the secondary foaming power during in-mold foam molding is obtained. Therefore, the appearance of the foamed molded product may deteriorate. On the other hand, when the content of the foaming agent is large, for example, it exceeds 10% by mass, the time required for the cooling step in the production process of the foamed molded article using the foamable particles becomes long and the productivity may be lowered.

(Foaming aid)
The foamable particles can contain a foaming aid together with the foaming agent.
The foaming aid is not particularly limited as long as it is conventionally used for foaming polystyrene resins. For example, aromatic organic compounds such as styrene, toluene, ethylbenzene, xylene, cyclohexane, methylcyclohexane, etc. Examples thereof include solvents having a boiling point of 200 ° C. or less under 1 atm, such as cycloaliphatic hydrocarbons, ethyl acetate, and butyl acetate.

The content of the foaming aid in the expandable particles is usually in the range of 0.3 to 2.5% by mass, and preferably in the range of 0.5 to 2% by mass.
When the content of the foaming aid is small, for example, less than 0.3% by mass, the plasticizing effect of the polystyrene resin may not be exhibited. On the other hand, if the content of the foaming aid is large and exceeds 2.5% by mass, the foamed molded product obtained by foaming the foamable particles may be shrunk or melted to deteriorate the appearance, or foamable. The time required for the cooling step in the production process of the foamed molded article using the particles may be long.

(Foaming)
The expandable particles of the present invention have high impact resistance and high expandability, and the expandability of the expandable particles (bulk multiple) of the expanded particles is preferably 5 times or more. The evaluation method will be described in Examples.

(4) Expanded particles The expanded particles of the present invention are obtained by pre-expanding the expandable particles of the present invention, specifically, water vapor (steam) having a gauge pressure of 0.004 to 0.09 MPa introduced in a sealed container. And pre-foamed to a predetermined bulk density.
Examples of the method include batch-type foaming in which steam is introduced, continuous foaming, and release foaming under pressure, and when necessary, air may be introduced simultaneously with water vapor.

(The bulk density)
The expanded particles of the present invention preferably have a bulk density of 0.010 to 0.200 g / cm ³ . When the bulk density of the foamed particles is less than 0.010 g / m ³ , the foamed molded product tends to shrink and the appearance may be impaired, and the mechanical strength may not be sufficient. On the other hand, when the bulk density of the expanded particles exceeds 0.200 g / m ³ , the merit of weight reduction as a foamed molded product may be impaired. A preferred bulk density of the expanded particles is 0.025 to 0.050 g / cm ³ .

(Average particle size)
The expanded particles of the present invention preferably have an average particle size of 0.5 to 8.0 mm. When the average particle diameter of the expanded particles is less than 0.5 mm, the foamability at the time of foam molding is low, and the elongation of the surface of the molded article may be deteriorated. On the other hand, if the average particle diameter of the expanded particles exceeds 8.0 mm, the filling properties of the expanded particles during the molding process may be insufficient. More preferably, the average particle size of the composite resin particles is 1.5 to 7.0 mm.

(5) Foam molded article A composite resin foam molded article comprising at least one modified resin component selected from a polycarbonate resin, a polyamide resin and a polyphenylene ether resin in addition to a polypropylene resin and a polystyrene resin,
Absorbance ratio (D698 / D1376) of the absorbance at 698 cm ⁻¹ derived from polystyrene resin (D698) and the absorbance at 1376 cm ⁻¹ derived from polypropylene resin (D1376) obtained from the infrared absorption spectrum inside the composite resin foam molded article. ) Is 2 to 30 times the absorbance ratio (D698 / D1376) obtained from the infrared absorption spectrum of the skin surface of the composite resin foam molded article.

The foam molded article of the present invention is a foam molded article obtained by foam molding composite resin particles obtained by subjecting the seed polymerization seed particles of the present invention and a styrene monomer to a seed polymerization method. Preferably there is.
Specifically, the foamed molded body is obtained by a method known in the art, for example, by filling the foamed particles into a mold (cavity) of a foam molding machine and heating again to foam the foamed particles while thermally melting the foamed particles. It is obtained by putting it on.

(density)
The foamed molded product of the present invention preferably has a density of 0.010 to 0.200 g / cm ³ . When the density of the foamed molded product is less than 0.010 g / cm ³ , the impact resistance may not be sufficient. On the other hand, when the density of the foamed molded product exceeds 0.200 g / cm ³ , the effect of reducing the weight of the foamed molded product is limited. The bulk density of a preferable foamed molded product is 0.025 to 0.050 g / cm ³ . The measuring method will be described in Examples.

(Heat-resistant)
The foamed molded product of the present invention has, for example, a dimensional change rate of 0 ≦ S ≦ 10 before and after a heat resistance test at a temperature of 90 ° C. for 168 hours. The measuring method will be described in Examples.

(Fusion rate)
The foamed molded product of the present invention has, for example, a fusion rate in the range of 20 to 100%. The measuring method will be described in Examples.

(chemical resistance)
The foamed molded article of the present invention has chemical resistance such that the appearance does not change even after 24 hours exposure to oils such as engine oil and brake oil, and chemicals such as grease, washer fluid, gasoline and light oil. The evaluation method will be described in Examples.

(Absorbance ratio)
The foamed molded article of the present invention has an absorbance ratio (D698) between the absorbance at 698 cm ⁻¹ derived from polystyrene resin (D698) and the absorbance at 1376 cm ⁻¹ derived from polypropylene resin (D1376) obtained from the infrared absorption spectrum inside. / D1376) is 2 to 30 times the absorbance ratio (D698 / D1376) obtained from the infrared absorption spectrum of the skin surface.
The method for measuring the absorbance ratio will be described in Examples.

When the ratio of the absorbance ratio is less than 2, the polystyrene component on the surface of the molded product becomes excessive, and the particles may be linked to each other at the time of foaming or the chemical resistance may be lowered. Furthermore, the foam moldability may be significantly reduced. On the other hand, if the ratio of the absorbance ratio exceeds 30 times, foam moldability may be lowered.
The magnification of the absorbance ratio is, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30.
The magnification of the preferred absorbance ratio is 3 to 20 times.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, the following Examples are only illustrations of this invention and this invention is not limited only to the following Examples.
In Examples and Comparative Examples, raw material resins, obtained seed particles, expandable particles, expanded particles, and expanded molded articles were evaluated as follows.

<Glass transition point of the modified resin component>
The glass transition point is measured by the method described in JIS K7121: 1987 “Method for measuring plastic transition temperature”. However, the sampling method and temperature conditions are as follows.
That is, using a differential scanning calorimeter DSC6220 type (manufactured by SII Nano Technology Co., Ltd.), about 6 mg of the sample is filled so that there is no gap at the bottom of the aluminum measurement container, and under a nitrogen gas flow rate of 20 mL / min, The temperature was raised from 30 ° C. at a rate of 20 ° C./min to a temperature 30 ° C. higher than the assumed glass transition temperature, quickly taken out after holding for 10 minutes, and allowed to cool in an environment of 25 ± 10 ° C. Thereafter, the midpoint glass transition temperature is calculated from the DSC curve obtained when the temperature is raised from 30 ° C. to the above-mentioned upper limit temperature again at a rate of 20 ° C./min. At this time, alumina is used as a reference material. The midpoint glass transition temperature is determined from the standard (9.3 “How to determine glass transition temperature”).

<Melting point of modified resin component and polypropylene resin>
The melting point is measured by the method described in JIS K7121: 1987 “Method for measuring transition temperature of plastic”. However, the sampling method and temperature conditions are as follows. That is, using a differential scanning calorimeter DSC6220 type (manufactured by SII Nano Technology Co., Ltd.), about 6 mg of the sample is filled so that there is no gap at the bottom of the aluminum measurement container, and under a nitrogen gas flow rate of 20 mL / min, The temperature was lowered from 30 ° C. to −40 ° C. and held for 10 minutes, the temperature was raised from −40 ° C. to 290 ° C. (1st Heating), held for 10 minutes, then cooled from 290 ° C. to −40 ° C. (Cooling), and held for 10 minutes— A DSC curve is obtained when the temperature is raised from 40 ° C. to 290 ° C. (2nd Heating). All the temperature increases / decreases are performed at a rate of 10 ° C./min, and alumina is used as a reference material. In this invention, melting | fusing point is the value which read the temperature of the top of the melting peak seen in a 2nd Heating process using the analysis software attached to an apparatus.

<Foaming properties of expandable particles>
The mass a (g) of about 2 g of expandable particles is weighed with two significant figures after the decimal point. The weighed expandable particles are put in a container, and it is confirmed that the temperature in the foaming tank is 90 ° C. or less. The container in which the expandable particles are put in the foaming tank is put, and water vapor with a gauge pressure of 0.03 MPa (vapor temperature: 106 C)), the inside of the foaming tank is pressurized to raise the temperature in the foaming tank to 102 to 106 ° C, and the foam is heated and foamed. At this time, the heating time is set to 1 minute, and the expansion ratio of the expanded particles immediately after taking out from the expansion tank is measured. The heating time is from the time when the temperature in the foaming tank becomes 102 ° C. or higher. The expansion ratio is obtained by placing the expanded particles in a graduated cylinder, measuring the volume b (cm ³ ), and dividing the volume b by the mass a.
From the obtained expansion ratio, the expandability of the expandable particles is evaluated based on the following criteria.
○ (Good): The expansion ratio is 30 times or more △ (Slightly bad): The expansion ratio is 5 times or more and less than 30 times × (Poor): The expansion ratio is less than 5 times

<Density of foam molding>
After molding, a test piece having a length of 75 × width of 300 × thickness of 35 mm was cut out from the foamed product dried at a temperature of 50 ° C. for 4 hours or more, and its mass a (g) and volume b (cm ³ ) were significant figures. It measures so that it may become 3 digits or more, and calculates the density of a foaming molding based on a following formula.
Density of foamed molded product (g / cm ³ ) = a / b

<Heat resistance of foamed molded product: 90 ° C.>
The change in the heating dimension of the foamed molded product is measured in accordance with the method B described in JIS K 6767: 1999 “Foamed Plastic-Polyethylene Test Method”, and the heat resistance of the foamed molded product is evaluated from the obtained result.
Specifically, a test piece having a length of 150 mm, a width of 150 mm, and a height of 20 mm is cut out from the foamed molded body. Then, on the surface of the test piece, three straight lines with a length of 50 mm directed in the vertical direction are written in parallel with each other at intervals of 50 mm, and three straight lines with a length of 50 mm directed in the horizontal direction are parallel with each other. Fill in every 50mm interval. Thereafter, the test piece is left in a hot air circulating drier at a temperature of 90 ° C. for 168 hours and then taken out, and is taken for 1 hour under the conditions of standard conditions (temperature 20 ± 2 ° C., humidity 65 ± 5%). Leave it over.
Next, the lengths of the six straight lines entered on the surface of the test piece are measured, and the arithmetic average value L1 of the lengths of the six straight lines is calculated. Then, the degree of change S is calculated based on the following formula, and the absolute value of the degree of change S is defined as a heating dimension change (/ 1000).
S = 1000 × (L1-50) / 50
From the heating dimensional change of the obtained foamed molded product, the heat resistance of the foamed molded product is evaluated based on the following criteria.
○ (good): small dimensional change (0 ≦ S ≦ 10) and good dimensional stability Δ (possible): dimensional change is seen (10 <S ≦ 15), but practical use is possible. X (impossible): dimensional change is remarkably observed (15 <S), impractical use is impossible <heat resistance of foamed molded article: 95 ° C.>
The heat resistance of the foamed molded product is evaluated in the same manner as the heat resistance at 90 ° C. except that the temperature of the hot air circulation dryer is 95 ° C. From the heating dimensional change of the obtained foamed molded product, the heat resistance of the foamed molded product is evaluated based on the following criteria.
◎ (excellent): small dimensional change (0 ≦ S ≦ 15), good dimensional stability and sufficiently practical at 95 ° C. (good): dimensional change is seen (15 <S ≦ 30), Practical use at 95 ° C is difficult but has excellent heat resistance. △ (possible): Although dimensional change is noticeable (30 <S ≤ 50), the effect of improving heat resistance is confirmed. ): Significant changes in dimensions (50 <S), impractical use in high temperature range regardless of 90 ° C or 95 ° C

<Fusion rate of foam molding>
A cutting line having a length of 300 mm and a depth of about 5 mm is put along the horizontal direction with a cutter on the upper surface of a 30 mm-thick rectangular foam-shaped body having an upper surface of length 400 mm × width 300 mm. The foamed molded product is divided into two. And about the expanded particle of the fracture surface of the foamed molded product divided into two, the number of expanded particles broken in the expanded particle (a) and the number of expanded particles broken at the interface between the expanded particles (b) Measure and calculate the fusion rate (%) based on the following formula.
Fusing rate (%) = 100 × (a) / [(a) + (b)]
The fusion rate of the obtained foamed molded product is evaluated based on the following criteria.
○ (good): indicates a fusion rate of 80% or more Δ (slightly bad): indicates a fusion rate of 20% or more and less than 80% × (bad): fusion rate of less than 20%

<Chemical resistance of foamed molded products>
A flat rectangular plate-shaped test piece having a length of 100 mm, a width of 100 mm, and a thickness of 20 mm was cut out from the foamed molded product so that the entire upper surface was formed from the skin of the foamed molded product, and the obtained test piece was at a temperature of 23 ° C. Leave for 24 hours under the condition of 50% humidity.
Next, 1 g of gasoline as a chemical is uniformly applied to the upper surface of the test piece and left for 60 minutes under the conditions of a temperature of 23 ° C. and a humidity of 50%. Thereafter, the chemical is wiped off from the upper surface of the test piece, and the upper surface of the test piece is visually observed to evaluate the chemical resistance based on the following criteria.
○ (Good): No change △ (Slightly bad): Surface softening × (Poor): Surface depression (shrinkage)

<Comprehensive evaluation>
Evaluation results of the obtained expandable particles and foamed molded product, that is, evaluation items related to productivity (foamability and fusion rate), evaluation items related to products (heat resistance (90 ° C. and 95 ° C.) and chemical resistance) Is comprehensively evaluated based on the following criteria.
◎ (Excellent): ◯ or higher in all evaluation items related to productivity and products ○ (Good): ◯ or higher in evaluation items related to productivity, but at least one item in the evaluation items related to products has △ Slightly bad): There are △ in the evaluation items related to productivity, and there is no “×” in the evaluation items related to products.

<Absorbance ratio of foam molded article>
The absorbance ratio (D698 / D1376) of the foam molded article is measured as follows.
In addition, each light absorbency obtained from an infrared absorption spectrum says the height of the peak originating in the vibration of each resin component contained in a composite resin particle.
About 10 randomly selected compacts, the skin surface (surface) that has not been cut at all, and the slice surface (inside) after slicing the skin with a ham slicer 0.5-1.5 mm Then, an infrared absorption spectrum is obtained by performing surface layer analysis by an infrared spectroscopic analysis ATR measurement method.
In this analysis, an infrared absorption spectrum in the depth range from the sample surface to several μm (about 2 μm) is obtained.
The individual absorbance ratio (D698 / D1376) is calculated from each infrared absorption spectrum, the arithmetic average of the individual absorbance ratios calculated for the surface is defined as the surface absorbance ratio, and the arithmetic average of the individual absorbance ratios calculated for the interior is the internal absorbance ratio. And
The absorbances D698 and D1376 are measured under the following conditions using a Thermo Scientific Fourier transform infrared spectrophotometer, trade name “NICOLET iS5”, and Thermo Scientific “iD5” as an ATR accessory.

(Measurement condition)
High refractive index crystal seed = Ge (germanium)
Incident angle = 45 ° ± 1 °
Measurement area = 4000 cm ^{−1 to} 675 cm ⁻¹
Fractional dependence of measurement depth = No correction Reflection count = 1 Detector = DTGSKBr
Resolution = 4cm ^-1
Number of integrations = 16 times Others: An infrared absorption spectrum is measured under the above conditions without contacting the sample, and the measured infrared absorption spectrum is used as the background. When measuring the sample, the measurement data is processed so that the background does not contribute to the measurement spectrum. In the ATR method, the intensity of the infrared absorption spectrum changes depending on the degree of adhesion between the sample and the high refractive index crystal. Therefore, the maximum load that can be applied with “iD5” of the ATR accessory is applied to perform the measurement with the contact degree being substantially uniform.
About the infrared absorption spectrum obtained on the above conditions, the peak process is performed as follows and each light absorbency is calculated | required.

The absorbance D698 at 698 cm ⁻¹ obtained from the infrared absorption spectrum is an absorbance corresponding to the absorption spectrum derived from the out-of-plane vibration of the benzene ring contained in the polystyrene resin. In this absorbance measurement, peak separation is not performed even when other absorption spectra overlap at 698 cm ⁻¹ . Absorbance D698 is a straight line connecting the 1400 cm ^-1 and 790 cm ^-1 as a baseline, means the maximum absorbance between 710 cm ^-1 and 685cm ^-1.
Further, the absorbance D1376 at 1376 cm ⁻¹ obtained from the infrared absorption spectrum is an absorbance corresponding to an absorption spectrum derived from CH ₃ methyl symmetrical variable bending vibration contained in the polypropylene resin. In this absorbance measurement, peak separation is not performed even if other absorption spectra overlap at 1376 cm ⁻¹ . Absorbance D1376 is a straight line connecting the 1400 cm ^-1 and 1340 cm ^-1 as a baseline, means the maximum absorbance between 1400 cm ^-1 and 1350 cm ^-1.

Example 1
(Preparation of seed particles)
Polypropylene resin PP1 (melting point 140 ° C .; manufactured by Prime Polymer Co., Ltd., brand: Prime Polypro F-744NP) and polyamide resin PA (Tg 45 ° C., Tm 220 ° C .; manufactured by Unitika Ltd., product name: Unitika Nylon 6 A1030BRT) 30 kg in total so that the mass ratio was 75:25, was put into a tumbler mixer and mixed for 10 minutes.
Next, the obtained resin mixture was supplied to an extruder (Toshiba Machine Co., Ltd., model: SE-65), melted and kneaded at a temperature of 200 to 250 ° C., granulated by an underwater cutting method, and oval (egg-like) ) To obtain seed particles. The average mass of the seed particles was 0.6 mg.

(First polymerization)
Next, 760 g of the obtained seed particles are put into a 5 liter autoclave with a stirrer (manufactured by Nitto High Pressure Co., Ltd.), 2,000 g of pure water as an aqueous medium, 10 g of magnesium pyrophosphate as a dispersant, and a surfactant. 0.5 g of sodium dodecylbenzenesulfonate as a mixture was added and stirred to suspend the seed particles in an aqueous medium, maintained for 10 minutes, and then heated to 70 ° C. to obtain an aqueous suspension.
Next, 380 g of a styrene monomer prepared by dissolving 0.8 g of dicumyl peroxide as a polymerization initiator in advance was added dropwise to the obtained aqueous suspension over 30 minutes. The seed particles were impregnated (absorbed) with the styrene monomer by holding for 30 minutes after the dropping.
Next, the temperature of the reaction system was raised to 140 ° C. and held at this temperature for 2 hours to polymerize the styrene monomer in the seed particles (first polymerization).

(Second polymerization)
Next, the temperature of the first polymerization reaction solution was lowered (cooled) to 125 ° C., and 1.5 g of sodium dodecylbenzenesulfonate as a surfactant was added. Thereafter, 860 g of a styrene monomer prepared by dissolving 4.5 g of dicumyl peroxide as a polymerization initiator in advance is dropped over 4 hours, and the seed particles are impregnated (absorbed). ), The styrene monomer was polymerized in the seed particles (second polymerization).
After completion of the dropwise addition, the temperature of the reaction system was maintained at 125 ° C. for 1 hour, and then heated to 140 ° C. and maintained at this temperature for 2 hours and 30 minutes to complete the polymerization to obtain composite resin particles.

(Production of expandable particles)
Next, the temperature of the mixed solution containing the composite resin particles was cooled to about 60 ° C., and the composite resin particles (about 2000 g) were taken out from the autoclave.
2,000 g of the obtained composite resin particles and 2 liters of water were again put in an autoclave with a capacity of 5 liters equipped with a stirrer. Furthermore, 300 g of butane (n-butane: i-butane = 7: 3) (520 mL, 15 parts by mass with respect to 100 parts by mass of the composite resin particles) was injected into the autoclave as a foaming agent. After the injection, the mixture was heated to 70 ° C. and stirred at this temperature for 4 hours to obtain expandable particles.
Thereafter, the mixed solution was cooled to room temperature, and the expandable particles were taken out from the autoclave and dehydrated and dried (about 2000 g).

(Production of expanded particles)
Next, 1,000 g of expandable particles are put into a pre-foaming machine having a can capacity of 40 liters (manufactured by Kasahara Kogyo Co., Ltd., model: PSX40), water vapor with a gauge pressure of 0.03 MPa is introduced into the can and heated, Foamed particles were obtained by pre-foaming to a bulk density of 0.029 g / cm ³ .
At the same time, the foamability was evaluated by introducing and heating water vapor with a gauge pressure of 0.03 MPa to foam the foamable particles for 1 minute.

(Production of foamed molded product)
Next, the obtained expanded particles were allowed to stand at room temperature (23 ° C.) for 1 day, and then filled into a cavity of a mold having an internal dimension of 400 mm × 300 mm × 50 mm.
Next, 0.29 MPa of water vapor is introduced into the mold for 50 seconds and heated, and then cooled until the maximum surface pressure of the foamed molded product is reduced to 0.001 MPa, and foam molding with a density of 0.029 g / cm ³ is performed. Got the body.
Under these molding conditions, the appearance and fusion of the obtained foamed molded article were both good.
The obtained molded foam was evaluated for heat resistance, fusion rate and chemical resistance.
The results are shown in Table 1 together with the raw materials and production conditions.

(Example 2)
Except for the following, in the same manner as in Example 1, foamed molded articles were obtained, and their physical properties including intermediate products were evaluated.
In (preparation of seed particles), a polypropylene resin PP2 (melting point 162 ° C .; grade: PL500A) is used instead of the polypropylene resin PP1, and a mass ratio of the polypropylene resin PP2 and the polyamide resin PA is used. In the first polymerization, 400 g of seed particles put in the autoclave and 0.4 g of dicumyl peroxide as a polymerization initiator were dissolved. In using 200 g of styrene monomer (second polymerization), 1400 g of styrene monomer prepared by dissolving 5.8 g of dicumyl peroxide as a polymerization initiator was dropped over 7 hours. The results are shown in Table 1 together with the raw materials and production conditions.

(Example 3)
In (preparation of seed particles), a polycarbonate resin PC (Tg 149 ° C .; product name: Panlite L-1250Y) was used instead of the polyamide resin PA, and a polypropylene resin PP1 and a polycarbonate resin PC were used. Were blended so that the mass ratio was 98: 2, and in the same manner as in Example 1, foamed molded articles were obtained and their physical properties including intermediate products were evaluated.
The results are shown in Table 1 together with the raw materials and production conditions.

Example 4
In (preparation of seed particles), the mass ratio of the polypropylene resin PP1, the polyamide resin PA, and the polyphenylene ether resin PPE (Tg 170 ° C .; manufactured by SABIC, trade name: EFN4230) is 96: 2: 2. Except for blending in the same manner as in Example 1, foamed molded articles were obtained and their physical properties including intermediate products were evaluated.
The results are shown in Table 1 together with the raw materials and production conditions.

(Example 5)
In (Preparation of seed particles), a foamed molded article was obtained in the same manner as in Example 1 except that the polypropylene resin PP1 and the polyamide resin PA were blended so that the mass ratio was 90:10. Their physical properties were evaluated.
The results are shown in Table 1 together with the raw materials and production conditions.

(Example 6)
(Preparation of seed particles), polypropylene resin PP3 (melting point 127 ° C .; manufactured by Prime Polymer Co., Ltd., brand: Prime Polypropylene F-794NV) was used instead of polypropylene resin PP1, and polypropylene resin PP3 and polyamide resin A foamed molded article was obtained in the same manner as in Example 1 except that PA was blended so that the mass ratio was 98: 2, and the physical properties including intermediate products were evaluated.
The results are shown in Table 1 together with the raw materials and production conditions.

(Example 7)
In (preparation of seed particles), a foamed molded article was obtained in the same manner as in Example 1 except that the polypropylene resin PP1 and the polyamide resin PA were blended so that the mass ratio was 98: 2, and an intermediate product was obtained. Their physical properties were evaluated.
The results are shown in Table 2 together with the raw materials and production conditions.

(Example 8)
In (preparation of seed particles), a polyphenylene ether resin PPE is used instead of the polyamide resin PA, and the polypropylene resin PP1 and the polyphenylene ether resin PPE are blended so that the mass ratio is 98: 2. Were obtained in the same manner as in Example 1, and foamed molded articles were obtained, and their physical properties including intermediate products were evaluated.
The results are shown in Table 2 together with the raw materials and production conditions.

Example 9
Except for the following, in the same manner as in Example 1, foamed molded articles were obtained, and their physical properties including intermediate products were evaluated.
In (preparation of seed particles), blending the polypropylene resin PP1 and the polyamide resin PA so that the mass ratio is 98: 2 (first polymerization), the seed particles to be put in the autoclave are 1000 g, and In using 430 g of a styrene monomer prepared by dissolving 1.0 g of dicumyl peroxide as a polymerization initiator (second polymerization), 3.0 g of dicumyl peroxide as a polymerization initiator 570 g of a styrenic monomer prepared by dissolving styrene was added dropwise over 2 hours. The results are shown in Table 2 together with the raw materials and production conditions.

(Comparative Example 1)
In (Preparation of seed particles), a foamed molded article was obtained in the same manner as in Example 1 except that only the polypropylene resin PP1 was used, and their physical properties including intermediate products were evaluated.
The results are shown in Table 2 together with the raw materials and production conditions.

(Comparative Example 2)
In (preparation of seed particles), a polyethylene resin PE (linear low density polyethylene, melting point 121 ° C .; manufactured by Prime Polymer Co., Ltd., brand: Harmolex NF444N) is used instead of the polypropylene resin PP1, and a polyethylene resin A foamed molded article was obtained in the same manner as in Example 1 except that PE and polyamide resin PA were blended so that the mass ratio was 98: 2, and their physical properties including intermediate products were evaluated.
The results are shown in Table 2 together with the raw materials and production conditions.

(Comparative Example 3)
Polypropylene resin PP1 (melting point 140 ° C .; manufactured by Prime Polymer Co., Ltd., brand: Prime Polypro F-744NP) and polyamide resin PA (Tg 45 ° C., Tm 220 ° C .; manufactured by Unitika Ltd., product name: Unitika Nylon 6 A1030BRT) , Polystyrene resin (Toyo Styrene Co., Ltd., product name: Toyostyrene GP, varieties: HRM-40) was mixed in a total mass of 30: 1 so that the mass ratio was 49: 1: 50, and the mixture was put into a tumbler mixer. Mixed for minutes.
Next, in the same manner as in Example 1, the obtained mixed resin was supplied to an extruder, melted and kneaded, granulated by an underwater cutting method, and formed into an oval shape (egg) to obtain composite resin particles. The average mass of the composite resin particles at this time was about 0.6 mg.
Next, in the same manner as in Example 1, the obtained composite resin particles were impregnated with a foaming agent to obtain expandable particles (about 2000 g).
Next, the obtained expandable particles were pre-expanded, but the expandability was low and expanded particles could not be obtained.
In Comparative Example 3, foamed particles were not obtained, so the foamable particles were filled as they were into a mold cavity having a 400 mm × 300 mm × 50 mm internal cavity, and 0.29 MPa water vapor was introduced into the mold for 50 seconds. Then, the molded body was produced by cooling until the maximum surface pressure of the foamed molded body decreased to 0.001 MPa.
The results are shown in Table 2 together with the raw materials and production conditions.

From the results in Tables 1 and 2, the following can be understood.
The foamed molded products of Examples 1 to 9 have better heat resistance than conventional foamed molded products while maintaining good moldability. If there are too many modified resin components, foamability and fusion rate (Example 1), in the case of imparting high heat resistance while maintaining productivity, the mass ratio is preferably 99/1 to 80/20, If the amount of the modified resin component is too small, a sufficient heat resistance improvement effect cannot be expected. ・ If the melting point of the polypropylene resin is high, the foam moldability may be lowered (Example 2), while the melting point of the polypropylene resin is low. If it is low, the heat resistance may decrease (Example 6).
-When the resin kneaded with the polypropylene resin is a polyamide resin or a polyphenylene ether resin, there is a higher heat resistance improvement effect (contrast with Examples 7 and 8 and Example 3).
-Expandable particles produced through extrusion kneading have extremely poor foamability, and expanded particles cannot be obtained. This is presumably because the absorbance ratio between the inside and the surface is 1.

1 Slice 2 Surface 3 Inside

Claims (9)

In addition to polypropylene resin and polystyrene resin, it is a composite resin foam molded article comprising at least one modified resin component selected from polycarbonate resin, polyamide resin and polyphenylene ether resin,
Absorbance ratio (D698 / D1376) of the absorbance at 698 cm ⁻¹ derived from polystyrene resin (D698) and the absorbance at 1376 cm ⁻¹ derived from polypropylene resin (D1376) obtained from the infrared absorption spectrum inside the composite resin foam molded article. ) Is 2 to 30 times the absorbance ratio (D698 / D1376) obtained from the infrared absorption spectrum of the skin surface of the composite resin foam molded article.   The composite resin foam molded article is subjected to a seed polymerization method by adding seed particles for seed polymerization containing the polypropylene resin and the modified resin component in a mass ratio of 99/1 to 80/20 and a styrene monomer. The composite resin foam molded article according to claim 1, which is a foam molded article obtained by subjecting the composite resin particles obtained by foam molding to foam molding.   The polypropylene resin has a melting point of 125 to 165 ° C, and the polycarbonate resin, polyamide resin and polyphenylene ether resin have a glass transition point of 145 to 180 ° C or a melting point of 190 ° C to 240 ° C. The composite resin foam molded article according to 1 or 2.   The composite resin foam molded article according to any one of claims 1 to 3, wherein the modified resin component is a polyamide-based resin, a polyphenylene ether-based resin, or a combination thereof. Seed particles for seed polymerization for obtaining composite resin particles for foam molding of the composite resin foam molded body according to any one of claims 1 to 4,
The seed particles for seed polymerization comprise a polypropylene resin and at least one modified resin component selected from a polycarbonate resin, a polyamide resin, and a polyphenylene ether resin at a mass ratio of 99/1 to 80/20. A seed particle for seed polymerization characterized by comprising.   The polypropylene resin has a melting point of 125 to 165 ° C, and the polycarbonate resin, polyamide resin and polyphenylene ether resin have a glass transition point of 145 to 180 ° C or a melting point of 190 ° C to 240 ° C. 6. Seed polymerization seed particles according to 5.   Composite resin particles obtained by subjecting the seed polymerization seed particles according to claim 5 or 6 and a styrene monomer to a seed polymerization method.   Expandable particles obtained by impregnating the composite resin particles according to claim 7 with a foaming agent.   Expanded particles obtained by pre-expanding the expandable particles according to claim 8.

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