JP5969938B2 - Expandable thermoplastic resin particles and production method thereof, pre-expanded particles, foamed molded product, resin composition for producing antistatic resin molded product - Google Patents

Description

 The present invention relates to expandable thermoplastic resin particles and methods for producing the same, pre-expanded particles, foamed molded articles, and resin compositions for producing antistatic foamed molded articles. Particularly, the present invention relates to an electronic device that requires antistatic performance and antistatic properties. Foamable thermoplastic resin particles capable of producing antistatic foamed moldings used as parts packaging materials, electronic component transport trays, etc., and methods for producing the same, prefoamed particles, foamed molded articles, and antistatic resin molded articles The present invention relates to a resin composition for production.

  As polyolefin-based resin foam molded articles having sustained antistatic performance, foamable resin particles blended with a polymer-type antistatic agent, and foam molded articles produced using the same are known (for example, patent documents). 1-3).

  Patent Document 1 discloses a non-crosslinked polypropylene resin composition containing 1 to 30% by weight of an ion conductive polymer type antistatic agent comprising an amphiphilic block copolymer containing an alkali metal salt of fluoroalkylsulfonic acid. Non-crosslinked polypropylene resin pre-expanded particles made of a product and non-cross-linked polypropylene resin pre-expanded particles filled in a mold that can be closed but cannot be sealed, and heated and molded with water vapor A cross-linked polypropylene resin in-mold foam molded article is disclosed.

  Patent Document 2 discloses polyolefin resin pre-expanded particles obtained by foaming polyolefin resin particles, the polyolefin resin particles being 100 parts by weight of polyolefin resin and 0.01 parts by weight of low molecular weight antistatic agent. And a polyolefin-based resin pre-expanded particle obtained from a polyolefin-based resin composition containing 5 parts by weight or more and 30 parts by weight or less of a polyether-polyolefin-based resin block copolymer system antistatic agent A foam-molded product obtained by heat-sealing is disclosed.

  Patent Document 3 discloses foamed particles obtained by foaming composite resin particles composed of a core layer composed of a polyolefin resin and a coating layer covering the core layer composed of a polyolefin resin, The polyolefin resin constituting the core layer is a crystalline polyolefin resin, and the polyolefin resin constituting the coating layer has a melting point (B) lower than the melting point (A) of the polyolefin resin constituting the core layer. And a difference [(A)-(B)] between the melting point (B) and the melting point (A) of the polyolefin resin constituting the core layer is more than 0 ° C. and not more than 80 ° C. Or a softening point (C) lower than the melting point (A) of the polyolefin resin constituting the core layer, and the softening point (C) and the melting point (A) of the polyolefin resin constituting the core layer; Difference (A)-(C)] is an amorphous polyolefin-based resin having a temperature exceeding 0 ° C. and not exceeding 100 ° C., and a polymer type antistatic agent is blended in the coating layer in an amount of 10 wt% to less than 50 wt%. A polyolefin-based resin expanded particle is disclosed.

Republished WO2008 / 075503 Republished WO2009 / 001645 JP 2009-173021 A

  However, the foamable thermoplastic resin particles produced by the above-mentioned conventional technology are heated and foamed into pre-foamed particles, which are then filled into the mold cavity and heated with steam or the like to be foam-molded in the mold. In the case of producing a foamed molded product, in order to impart sufficient antistatic performance to the obtained foamed molded product, it is necessary to add an antistatic agent in a considerably large amount, resulting in an increase in the cost of the foamed molded product. There was a problem.

  The present invention has been made in view of the above circumstances, and expandable thermoplastic resin particles capable of manufacturing a foamed molded article having sufficient sustained antistatic performance even with a small addition amount of an antistatic agent, a method for manufacturing the same, and the foaming It is an object of the present invention to provide pre-expanded particles and foam-molded products obtained from heat-resistant thermoplastic resin particles, and a resin composition for producing an antistatic resin-molded product.

The foamable thermoplastic resin particle of the present invention comprises a thermoplastic resin, a foaming agent, an ion conductive polymer antistatic agent containing an ionic surfactant, and a polyether compound. .
The thermoplastic resin preferably contains a rubber component, and the rubber content with respect to the thermoplastic resin is more preferably 1.0 to 8.0% by mass.
The ion conductive polymer antistatic agent preferably contains an anionic surfactant, and the anionic surfactant is an alkali metal salt of dodecylbenzenesulfonic acid or an alkali metal salt of trifluoromethanesulfonic acid. It is more preferable.
The polyether compound is preferably polyethylene glycol, more preferably 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin. More preferably, the number average molecular weight (Mn) of the glycol is in the range of 200-1500.
In a resin supply apparatus, a foaming agent is press-fitted and kneaded into a molten resin containing the ion conductive polymer type antistatic agent, the polyether-based compound, and the thermoplastic resin, and the foamed agent-containing molten resin is resinized. Manufactured by a melt extrusion method in which the extrudate is cut while being extruded into a cooling liquid directly from a small hole of a die attached to the tip of the supply device, and the extrudate is cooled and solidified by contact with the cooling liquid. Are preferred.
The thermoplastic resin is preferably a polystyrene-based resin or an impact-resistant polystyrene-based resin.

  The pre-expanded particles of the present invention are obtained by heating and foaming the expandable thermoplastic resin particles of the present invention.

The foamed molded article of the present invention is obtained by filling the pre-expanded particles of the present invention into a cavity of a molding die and heating and molding in the mold.
The foam-molded article of the present invention is a foam-molded article obtained by filling pre-foamed particles obtained by heating and foaming expandable thermoplastic resin particles into a cavity of a mold, and heating and molding in-mold. In the invention, the thermoplastic resin contains an ionic conductive polymer type antistatic agent containing an ionic surfactant and a polyether compound.
The thermoplastic resin preferably contains a rubber component, and the rubber content with respect to the thermoplastic resin is more preferably 1.0 to 8.0% by mass.
The ion conductive polymer antistatic agent preferably contains an anionic surfactant, more preferably an alkali metal salt of dodecylbenzenesulfonic acid or an alkali metal salt of trifluoromethanesulfonic acid.
The polyether compound is preferably polyethylene glycol, more preferably the polyethylene glycol is blended in an amount of 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin. More preferably, the number average molecular weight (Mn) of the glycol is in the range of 200-1500.
The thermoplastic resin is preferably a polystyrene-based resin or an impact-resistant polystyrene-based resin.

The resin composition for producing an antistatic resin molded article of the present invention contains one or both of a thermoplastic resin, an ion conductive polymer type antistatic agent containing an ionic surfactant, and a polyether compound. It is characterized by.
The thermoplastic resin preferably contains a rubber component, and the rubber content with respect to the thermoplastic resin is more preferably 1.0 to 8.0% by mass.
The ion conductive polymer antistatic agent preferably contains an anionic surfactant, more preferably an alkali metal salt of dodecylbenzenesulfonic acid or an alkali metal salt of trifluoromethanesulfonic acid.
The polyether compound is preferably polyethylene glycol, more preferably the polyethylene glycol is blended in an amount of 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin. More preferably, the number average molecular weight (Mn) of the glycol is in the range of 200-1500.
The thermoplastic resin is preferably a polystyrene-based resin or an impact-resistant polystyrene-based resin.

The method for producing expandable thermoplastic resin particles of the present invention includes a die in which a foaming agent is press-fitted and kneaded into a thermoplastic resin melted in a resin supply device, and a foamed agent-containing molten resin is attached to the tip of the resin supply device. In the method for producing expandable thermoplastic resin particles by a melt extrusion method in which the extrudate is cut while being extruded directly into the cooling liquid from the small holes of the melt, and the extrudate is cooled and solidified by contact with the cooling liquid. The foaming agent is press-fitted and kneaded into a molten resin containing the thermoplastic resin, an ionic conductive polymer type antistatic agent containing an ionic surfactant, and a polyether compound. The molten resin is extruded from the small hole of the die.
The thermoplastic resin preferably contains a rubber component, and the rubber content with respect to the thermoplastic resin is more preferably 1.0 to 8.0% by mass.
The ion conductive polymer antistatic agent preferably contains an anionic surfactant, more preferably an alkali metal salt of dodecylbenzenesulfonic acid or an alkali metal salt of trifluoromethanesulfonic acid.
The polyether compound is preferably polyethylene glycol, more preferably the polyethylene glycol is blended in an amount of 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin. More preferably, the number average molecular weight (Mn) of the glycol is in the range of 200-1500.
The thermoplastic resin is preferably a polystyrene-based resin or an impact-resistant polystyrene-based resin.

  The foamable thermoplastic resin particles of the present invention include a thermoplastic resin, a foaming agent, an ionic surfactant, for example, an ionic conductive polymer antistatic agent containing an anionic surfactant, a polyether compound, In comparison with foamable thermoplastic resin particles that do not contain a polyether compound, the decrease in ion conductive polymer antistatic agent during preliminary foaming and in-mold foam molding is reduced. Even if the addition amount of the inhibitor is small, it is possible to produce a foamed molded article having sufficient sustained antistatic performance.

  The method for producing expandable thermoplastic resin particles of the present invention includes a die in which a foaming agent is press-fitted and kneaded into a thermoplastic resin melted in a resin supply device, and a foamed agent-containing molten resin is attached to the tip of the resin supply device. In the method for producing expandable thermoplastic resin particles by a melt extrusion method in which the extrudate is cut while being extruded directly into the cooling liquid from the small holes of the melt, and the extrudate is cooled and solidified by contact with the cooling liquid. The foaming agent is press-fitted and kneaded into a molten resin containing the thermoplastic resin, an ionic conductive polymer type antistatic agent containing an ionic surfactant, and a polyether compound. Since the molten resin is extruded from the small holes of the die, as described above, the foamable thermoplastic resin particles that can produce a foamed molded article having sufficient antistatic performance even with a small amount of the antistatic agent added. It can be efficiently produced at low cost.

  The foamed molded article of the present invention comprises an ionic surfactant, for example, an ionic conductive polymer type antistatic agent containing an anionic surfactant, and a polyether compound. There is little decrease in the ion conductive polymer type antistatic agent at the time of in-mold foam molding, and even if the addition amount of the antistatic agent is small, it is excellent with sufficient sustained antistatic performance.

  The resin composition for producing an antistatic resin molded article of the present invention comprises an ion conductive polymer type antistatic agent containing an ionic surfactant, for example, an anionic surfactant, and a polyether type resin in a thermoplastic resin. Since the composition includes a compound, by blending as a master batch for adding an ion conductive polymer antistatic agent and a polyether compound to the thermoplastic resin in the method for producing foamable thermoplastic resin particles, Expandable thermoplastic resin particles in which an ion conductive polymer antistatic agent and a polyether compound are uniformly dispersed throughout the particles can be easily obtained.

It is a block diagram which shows an example of the manufacturing apparatus of the foamable thermoplastic resin particle by a melt extrusion method.

(Foaming thermoplastic resin particles)
The foamable thermoplastic resin particle of the present invention comprises a thermoplastic resin, a foaming agent, an ion conductive polymer antistatic agent containing an ionic surfactant, and a polyether compound. .
In the expandable thermoplastic resin particles of the present invention, the ion conductive polymer antistatic agent and the polyether compound are uniformly contained in the entire expandable thermoplastic resin particles (excluding internal bubbles). A configuration is preferred.

  Although the kind of thermoplastic resin used for the foamable thermoplastic resin particles of the present invention is not limited, for example, polystyrene resin, polyethylene resin, polypropylene resin, polyester resin, vinyl chloride resin, ABS resin, AS resin Etc. can be used alone or in admixture of two or more. Furthermore, it is possible to use a recovered resin of a thermoplastic resin obtained after being used once as a resin product. In particular, polystyrene resins such as amorphous polystyrene (GPPS) and high impact polystyrene (HIPS: high impact polystyrene) are preferably used.

  The polystyrene resin is not particularly limited. For example, homopolymers of styrene monomers such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, i-propylstyrene, dimethylstyrene, bromostyrene, or the like. A polystyrene resin containing 50% by mass or more of styrene is preferable.

  The polystyrene resin may be a copolymer of the styrene monomer and a vinyl monomer copolymerizable with the styrene monomer, the main component of which is the styrene monomer. Examples of such vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, alkyl (meth) acrylates such as cetyl (meth) acrylate, (meth) acrylonitrile, dimethyl maleate, In addition to dimethyl fumarate, diethyl fumarate, and ethyl fumarate, bifunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate are exemplified.

  If a polystyrene resin is the main component, other resins may be added. Examples of the resin to be added include polybutadiene, styrene-butadiene copolymer to improve the impact resistance of the foam molded article. Examples thereof include rubber-modified polystyrene resins to which a diene rubber-like polymer such as a polymer, ethylene-propylene-nonconjugated diene three-dimensional copolymer is added, and high-impact polystyrene resins such as high-impact polystyrene. Alternatively, a polyethylene resin, a polypropylene resin, an acrylic resin, an acrylonitrile-styrene copolymer, an acrylonitrile-butadiene-styrene copolymer, and the like can be given.

As raw material styrene resins, non-recycled polystyrene resins (virgin polystyrene) such as ordinary polystyrene resins available on the market, polystyrene resins newly prepared by suspension polymerization methods, etc. are used. In addition, a regenerated polystyrene resin obtained by regenerating a used polystyrene resin foam molded article can be used.
As this recycled polystyrene-based resin, used polystyrene-based resin foam molded products, for example, fish boxes, household appliance cushioning materials, food packaging trays, etc. are recovered and recycled by the limonene dissolution method or heating volume reduction method. Can be used. In addition, recycled polystyrene resins that can be used are not only those obtained by reprocessing used polystyrene resin foam moldings, but also household electrical appliances (for example, televisions, refrigerators, washing machines, air conditioners, etc.) In addition, a recycled polystyrene resin obtained by pulverizing, melt-kneading, and re-pelletizing a non-foamed polystyrene resin molded product separated and collected from office equipment (for example, a copying machine, a facsimile machine, a printer, etc.) can be used.

As the thermoplastic resin, those containing a rubber component are preferable. Examples of the thermoplastic resin containing rubber include, for example, a polystyrene resin as a main component, polybutadiene, styrene-butadiene copolymer, ethylene-propylene-nonconjugated diene three-dimensional copolymer, acrylonitrile-butadiene-styrene copolymer. And rubber-modified polystyrene resin to which a diene rubber-like polymer such as is added.
The rubber component makes it easy to form an ion network structure necessary for exhibiting antistatic performance in the foamable thermoplastic resin particles. For this reason, the foamable thermoplastic resin particles contain a rubber component, so that the antistatic effect is enhanced, and the amount of the ion conductive polymer type charging agent to be described later can be further reduced.

  When the thermoplastic resin contains a rubber component, the rubber content in the thermoplastic resin is preferably 1.0 to 8.0% by mass, more preferably 2.0 to 6.0% by mass, and 3.0 to 5.0 mass% is still more preferable. If it is more than the said lower limit, it will be easy to aim at the further improvement of the antistatic effect. If it is below the said upper limit, it will be easier to raise the bulk expansion ratio of an expandable thermoplastic resin particle (for example, 40 times or more).

  Examples of the foaming agent contained in the expandable thermoplastic resin particles of the present invention include propane, n-butane, isobutane, n-pentane, isopentane, neopentane and other aliphatic hydrocarbons, 1,1-dichloro-1-fluoroethane ( HCFC-141b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123), chlorodifluoromethane (HCFC-22), 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) and other chlorofluorocarbons, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC- 134a), fluorocarbons such as difluoromethane (HFC-32), various alcohols, carbon dioxide, water, and Include physical blowing agents such as iodine, it can be used in combination one or more of these. Among these, particularly preferable blowing agents include n-butane, isobutane, n-pentane, and isopentane. The addition amount of a foaming agent shall be the range of 1-15 mass parts with respect to 100 mass parts of polystyrene-type resins, More preferably, it shall be the range of 3-12 mass parts.

(Ion conductive polymer antistatic agent)
The ionic conductive polymer type antistatic agent contained in the foamable thermoplastic resin particles of the present invention is obtained by adding an ionic surfactant, for example, an anionic surfactant, to a base polymer component. is there. Although it does not specifically limit as a high molecular component, For example, the amphiphilic block copolymer which has a structure where the hydrophilic polymer segment (hydrophilic part) and the hydrophobic polymer segment (hydrophobic part) couple | bonded alternately is mentioned. It is done. The hydrophobic part is preferably an olefin polymer and the hydrophilic part is preferably an ether polymer.

  Examples of the olefin constituting the olefin polymer include olefins such as ethylene, propylene, butene, pentene, and hexene. Examples of the monomer that constitutes the ether polymer include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. The chemical bond between the olefin polymer and the ether polymer is not particularly limited, and examples thereof include an ester bond, an amide bond, and an ether bond. The number average molecular weight of the amphiphilic block copolymer is preferably in the range of 1000 to 100,000, and more preferably in the range of 3000 to 40000.

The ionic surfactant added to the ionic conductive polymer type antistatic agent is an ionic surfactant that can impart antistatic performance when mixed with a thermoplastic resin, for example, anionic surfactant Agents, cationic surfactants, and amphoteric surfactants.
Anionic surfactants include alkali metal salt of dodecylbenzenesulfonic acid, alkali metal salt of bistrifluoromethanesulfonimide, alkali metal salt of trifluoromethanesulfonic acid, alkali metal salt of octylbenzenesulfonic acid, alkali metal of lauryl sulfate Salt).
Examples of the cationic surfactant include benzyltrimethylammonium halide, benzyltriethylammonium halide, dodecylpyridinium halide, and the like.
Examples of amphoteric surfactants include dodecylaminomethyldimethylsulfopropylbetaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauroylmethyl-β-alanine, and the like.
Among these various ionic surfactants, anionic surfactants are preferable, and among them, alkali metal salts of dodecylbenzenesulfonic acid, alkali metal salts of trifluoromethanesulfonic acid, and the like are preferable. The alkali metal salt is preferably a sodium salt or a potassium salt.

  The amount of the ionic surfactant added to the ion conductive polymer type antistatic agent is preferably in the range of 0.2 to 2.0% by mass, and 0.4 to 1.2% by mass in the polymer component. The range of is more preferable.

  The ion conductive polymer antistatic agent can be appropriately prepared by mixing the polymer component and the anionic surfactant. Moreover, it can also select and use suitably from various commercial items. Examples of such commercially available products include “Peletron HS” (trade name) manufactured by Sanyo Chemical Industries, “Pelestat NC6322” (trade name) manufactured by the same company, “Peletron PVH” (trade name) manufactured by the same company, “Pelestat 230” (trade name) manufactured by Sanko Chemical Co., Ltd., “Sanconol TBX-65” (trade name), etc.

  The amount of the ion conductive polymer type antistatic agent contained in the foamable thermoplastic resin particles of the present invention is preferably in the range of 5 to 30 parts by mass, and in the range of 10 to 20 parts by mass per 100 parts by mass of the thermoplastic resin. Is more preferable. When the amount of the ion conductive polymer antistatic agent is less than the above range, sufficient antistatic performance cannot be imparted to the foamed molded article to be produced. When the ion conductive polymer type antistatic agent exceeds the above range, the antistatic performance reaches its peak and the cost increases.

(Polyether compound)
Examples of the polyether compound contained in the expandable thermoplastic resin particles of the present invention include compounds having a plurality of ether structures in the molecule, such as polyethylene glycol and polypropylene glycol.

  The number average molecular weight (Mn) of the polyethylene glycol is preferably in the range of 200 to 2000, and more preferably in the range of 200 to 1500. If the number average molecular weight (Mn) is less than 200, formation of an ion network structure necessary for exhibiting the antistatic performance is insufficient, and the predetermined antistatic performance may not be exhibited. Exceeding this is not preferable because crystallization proceeds between molecules of polyethylene glycol or within a molecular chain, and thus a predetermined antistatic performance may not be exhibited.

  The amount of the polyether compound contained in the expandable thermoplastic resin particles of the present invention is preferably in the range of 0.2 to 3.0 parts by mass, and 0.5 to 2.0 parts by mass per 100 parts by mass of the thermoplastic resin. A range is more preferred.

  The foamable thermoplastic resin particles may contain a foam nucleating agent such as liquid paraffin, aromatic hydrocarbon, and inorganic foam nucleating agent, if necessary.

(Resin composition for producing antistatic resin molding)
One or both of the ion conductive polymer type antistatic agent and the polyether compound may be the same kind of thermoplastic resin as the thermoplastic resin of the foamable thermoplastic resin particles of the present invention or another kind of compatible resin. It can also be mixed with a thermoplastic resin and used as a masterbatch for producing expandable thermoplastic resin particles (resin composition for producing an antistatic resin molding).

  In the foamable thermoplastic resin particles of the present invention, additives such as a foam nucleating agent, a crosslinking agent, a plasticizer, a filler, a flame retardant, a flame retardant aid, a lubricant, and a colorant are added within a range that does not impair physical properties. In addition, if powder metal soaps such as zinc stearate are applied to the surface of the expandable styrene resin particles, polystyrene resin pre-expanded in the pre-expanding step of expandable thermoplastic resin particles This is preferable because the bonding between particles can be reduced.

  The particle diameter of the expandable thermoplastic resin particles of the present invention is not particularly limited, but is usually preferably in the range of 0.5 to 3.0 mm, more preferably in the range of 0.7 to 2.0 mm. The shape of the particles is not particularly limited, but is preferably spherical or substantially spherical.

The foamable thermoplastic resin particles of the present invention include a thermoplastic resin, a foaming agent, an ionic surfactant, for example, an ionic conductive polymer antistatic agent containing an anionic surfactant, a polyether compound, In comparison with foamable thermoplastic resin particles that do not contain a polyether compound, the decrease in ion conductive polymer antistatic agent during preliminary foaming and in-mold foam molding is reduced. Even if the addition amount of the inhibitor is small, it is possible to produce a foamed molded article having sufficient sustained antistatic performance.
Furthermore, the foamable thermoplastic resin particles can further reduce the amount of the antistatic agent added by including a rubber component.

(Method for producing foamable thermoplastic resin particles)
The method for producing foamable thermoplastic resin particles of the present invention includes a thermoplastic resin, an ion conductive polymer antistatic agent containing an ionic surfactant, a foaming agent, and a polyether compound. The melt extrusion method which shape | molds molten resin to a granule is mentioned.
Examples of the melt extrusion method include the following methods.
First, a foaming agent is press-fitted and kneaded into a molten resin containing a thermoplastic resin, an ionic conductive polymer type antistatic agent, and a polyether compound to obtain a foaming agent-containing molten resin. While cutting the extrudate while extruding the obtained foaming agent-containing molten resin directly into the cooling liquid from the small holes, the extrudate is cooled and solidified by contact with the cooling liquid.
By using the melt extrusion method, expandable thermoplastic resin particles in which an ion conductive polymer type antistatic agent, a polyether-based compound, and a foaming agent are uniformly dispersed in a thermoplastic resin can be obtained. For this reason, this method can make it easy to form the ion network structure required in order to exhibit antistatic performance in an expandable thermoplastic resin particle. The foamable thermoplastic resin particles obtained by this method can enhance the antistatic effect and can further reduce the addition amount of the ion conductive polymer type charging agent.

An example of a method for producing expandable thermoplastic resin particles by the melt extrusion method will be described below with reference to FIG.
In the method for producing expandable thermoplastic resin particles in this embodiment, a foaming agent is press-fitted and kneaded into a thermoplastic resin melted in a resin supply device, and a foamed agent-containing molten resin is attached to the tip of the resin supply device. Extrude directly into the cooling liquid from the small hole of the die, and simultaneously extrude and cut the extrudate with a high-speed rotary blade, and cool and solidify the extrudate by contact with the liquid to obtain expandable thermoplastic resin particles In a method for producing expandable thermoplastic resin particles by an extrusion method, in a thermoplastic resin, a foaming agent, an ionic surfactant, for example, an ionic conductive polymer type antistatic agent containing an anionic surfactant, It is characterized by adding an ether compound and uniformly containing the whole foamable thermoplastic resin particles (excluding internal bubbles). Here, the ion conductive polymer antistatic agent and the polyether compound may be the same as those described above.

  FIG. 1 is a configuration diagram showing an example of a production apparatus used in the method for producing expandable thermoplastic resin particles of the present invention. The production apparatus of this example includes an extruder 1 as a resin supply apparatus, and an extruder 1. A die 2 having a large number of small holes attached to the tip of the resin, a raw material supply hopper 3 for introducing a resin raw material or the like into the extruder 1, and a foaming agent through the foaming agent supply port 5 to the molten resin in the extruder 1. A cutting chamber in which a cooling liquid (for example, cooling water) is brought into contact with the high pressure pump 4 to be press-fitted and a resin discharge surface in which a small hole of the die 2 is formed, and the cooling liquid is circulated and supplied into the chamber. 7, a cutter 6 rotatably provided in the cutting chamber 7 so as to cut the resin extruded from the small hole of the die 2, and a foaming property carried along with the flow of the cooling liquid from the cutting chamber 7 Liquid for cooling thermoplastic resin particles And a dehydrating dryer 10 with a solid-liquid separating function to obtain foamed thermoplastic resin particles by dehydrating and drying, and a water tank 8 for storing a cooling liquid separated by the dehydrating dryer 10 with a solid-liquid separating function, A high-pressure pump 9 for sending the cooling liquid in the water tank 8 to the cutting chamber 7 and a storage container 11 for storing the foamed thermoplastic resin particles dehydrated and dried by the dehydration dryer 10 with a solid-liquid separation function are provided. It is configured.

  As the extruder 1, either an extruder using a screw or an extruder not using a screw can be used. Examples of the extruder using a screw include a single-screw extruder, a multi-screw extruder, a vent-type extruder, and a tandem extruder. Examples of the extruder that does not use a screw include a plunger type extruder and a gear pump type extruder. Moreover, any extruder can use a static mixer. Among these extruders, an extruder using a screw is preferable from the viewpoint of productivity. Moreover, the conventionally well-known thing used in the granulation method by melt extrusion of resin can also be used for the cutting chamber 7 which accommodated the cutter 6. FIG.

  In order to produce foamable thermoplastic resin particles using the production apparatus shown in FIG. 1, first, a raw material thermoplastic resin, an ion conductive polymer type antistatic agent, a polyether compound, and, if necessary, a fluid Desired additives such as paraffin, aromatic hydrocarbons, inorganic foam nucleating agent, and foam nucleating agent are weighed and fed into the extruder 1 from the raw material supply hopper 3. The raw material thermoplastic resin may be mixed in advance in the form of pellets or granules and then charged from one raw material supply hopper. For example, when a plurality of lots are used, the supply amount for each lot may be reduced. A plurality of adjusted raw material supply hoppers may be charged and mixed in an extruder. Also, when using a combination of recycled materials from multiple lots, mix the raw materials from multiple lots in advance and remove foreign matter using appropriate sorting methods such as magnetic sorting, sieving, specific gravity sorting, and air blowing sorting. It is preferable to keep it.

  A thermoplastic resin, an ion conductive polymer antistatic agent, a polyether compound, and other additives are fed into the extruder 1 and then mixed while heating at a temperature at which the thermoplastic resin melts to obtain a molten resin. . While the molten resin is being transferred to the die 2 side, the blowing agent is press-fitted from the blowing agent supply port 5 by the high-pressure pump 4 and mixed with the molten resin. The foaming agent-containing molten resin is moved to the tip side while further kneading through a foreign matter removing screen provided in the extruder 1 as necessary, and the foaming agent-containing molten resin is attached to the tip of the extruder 1. The die 2 is extruded through a small hole.

  The resin discharge surface in which the small hole of the die 2 is drilled is disposed in the cutting chamber 7 in which the cooling liquid is circulated and supplied into the chamber, and is pushed into the cutting chamber 7 from the small hole of the die 2. A cutter 6 is rotatably provided so as to cut the resin. When the foaming agent-containing molten resin is extruded into the cooling liquid from the small hole of the die 2 attached to the tip of the extruder 1, the extruded molten resin (extruded product) is cut by the cutter 6 and simultaneously brought into contact with the cooling liquid. Then, it is rapidly cooled and solidified with foaming being suppressed to form expandable thermoplastic resin particles.

  The formed foamable thermoplastic resin particles are transferred from the cutting chamber 7 to the flow of the cooling liquid and carried to the dehydrating dryer 10 with a solid-liquid separation function. Here, the foamable thermoplastic resin particles are used as the cooling liquid. Separate and dry. The dried foamable thermoplastic resin particles are stored in the storage container 11.

  According to the method for producing expandable thermoplastic resin particles of this embodiment, an ion conductive polymer type antistatic agent containing a foaming agent and an ionic surfactant, for example, an anionic surfactant, in the thermoplastic resin. And a polyether compound are added uniformly to the entire foamable thermoplastic resin particles (excluding internal bubbles), so that sufficient antistatic performance can be achieved even with a small amount of antistatic agent added. It is possible to efficiently and inexpensively produce expandable thermoplastic resin particles capable of producing a foam-molded article having the above.

(Pre-expanded particles and foamed molded product)
The expandable thermoplastic resin particles of the present invention are pre-expanded by heating by steam heating or the like using a well-known apparatus and method in the field of manufacturing a foamed resin molded product, thereby forming pre-expanded particles. The pre-expanded particles are pre-expanded so as to have a bulk density equivalent to the density of the foamed molded product to be manufactured. In the present invention, the bulk density is not limited, usually being in the range of 0.010~0.50g / cm ^3, it is preferably in the range of 0.015~0.20g / cm ^3, 0 More preferably, it is in the range of 0.020 to 0.10 g / cm ³ .
The bulk expansion ratio of the pre-expanded particles is determined in consideration of the use of the foamed molded product to be manufactured, and is preferably 10 times or more (bulk density 0.10 g / cm ³ or less), preferably 30 times or more (bulk density). 0.033 g / cm ³ or less) is more preferable, and 40 times or more (bulk density 0.025 g / cm ³ or less) is more preferable. If the above-mentioned bulk foaming factor is not less than the above lower limit value, it can be applied to foam molded articles for various uses.

In the present invention, the bulk density of the pre-expanded particles refers to those measured in accordance with JIS K6911: 1995 “General Test Method for Thermosetting Plastics”.
<Bulk density of pre-expanded particles>
First, Wg was sampled from pre-expanded particles as a measurement sample, this measurement sample was naturally dropped into a graduated cylinder, and the volume Vcm ³ of the measurement sample dropped into the graduated cylinder was measured using an apparent density measuring instrument based on JIS K6911. The bulk density of the pre-expanded particles is measured based on the following formula.
Bulk density (g / cm ³ ) = mass of measurement sample (W) / volume of measurement sample (V)

<Bulk expansion ratio of pre-expanded particles>
Moreover, the bulk expansion ratio of the pre-expanded particles is a numerical value calculated by the following equation.
Bulk foaming factor = 1 / bulk density (g / cm ³ )

The pre-expanded particles are filled in the cavity of the mold using a well-known apparatus and method in the field of manufacturing a foamed resin molded body, heated by steam heating or the like, and subjected to in-mold foam molding, foaming A molded body is manufactured.
Although the density of the foamed molded article of the present invention is not particularly limited, but usually is in the range of 0.010~0.50g / cm ^3, it is preferably in the range of 0.015~0.20g / cm ³ , 0.020 to 0.10 g / cm ³ is more preferable.
The expansion ratio of the foamed molded product is determined in consideration of the use of the foamed molded product to be manufactured, and is preferably 10 times or more (density 0.10 g / cm ³ or less), preferably 30 times or more (density 0.033 g). / Cm ³ or less), more preferably 40 times or more (density 0.025 g / cm ³ or less). If the expansion ratio is not less than the above lower limit value, it can be applied to foam molded articles for various uses.

In the present invention, the density of the foamed molded product refers to the density of the foamed molded product measured by the method described in JIS K7122: 1999 “Measurement of foamed plastic and rubber-apparent density”.
<Density of foam molding>
A test piece of 50 cm ³ or more (100 cm ³ or more in the case of semi-rigid and soft materials) was cut so as not to change the original cell structure of the material, its mass was measured, and calculated by the following formula.
Density (g / cm ³ ) = Test piece mass (g) / Test piece volume (cm ³ )
Test piece condition adjustment and measurement test pieces were cut out from samples that had passed 72 hours or more after molding, and were subjected to atmospheric conditions of 23 ° C. ± 2 ° C. × 50% ± 5% or 27 ° C. ± 2 ° C. × 65% ± 5%. It has been left for more than an hour.

<Folding multiple of foamed molded product>
Further, the expansion factor of the foamed molded product is a numerical value calculated by the following equation.
Foaming factor = 1 / density (g / cm ³ )

  The foamed molded article of the present invention contains an ionic surfactant, for example, an ionic conductive polymer type antistatic agent containing an anionic surfactant, and a polyether compound in a thermoplastic resin. In addition, there is little decrease in the ion conductive polymer type antistatic agent at the time of preliminary foaming and in-mold foaming, and even if the amount of the antistatic agent added is small, it has excellent sustained antistatic performance.

[Materials used]
(Thermoplastic resin)
<General-purpose polystyrene resin (GPPS)>
GPPS manufactured by Toyo Styrene Co., Ltd .: trade name “Toyostyrene HRM26”, rubber content = 0 mass%
GPPS manufactured by Toyo Styrene Co., Ltd .: trade name Toyostyrene HRM10N ”, rubber content = 0 mass%
<Impact-resistant polystyrene resin (HIPS)>
HIPS made by PS Japan Co., Ltd .: trade name “E641N”, rubber content = 6.0% by mass
HIPS made by PS Japan Co., Ltd .: trade name “H758K”, rubber content = 7.5% by mass
<Polybutadiene-polystyrene copolymer>
Asahi Kasei Kogyo Co., Ltd. Polybutadiene-polystyrene copolymer: Trade name “Tufprene A”, rubber content = 60 mass%

<Method for measuring rubber content in thermoplastic resin>
The rubber content in the thermoplastic resin was determined by the following measurement method.
A sample 0.1 to 0.5 mg was precisely weighed and wrapped with a ferromagnetic metal body having a Curie point of 590 ° C. (Pyrofoil: manufactured by Nihon Analytical Industries, Ltd.). The sample wrapped with pyrofoil was disassembled with a Curie Point pyrolyzer JPS-700 type (manufactured by Nippon Analytical Industries, Ltd.). The butadiene monomer and 4-vinylcyclohexane produced from the decomposed sample were measured with a gas chromatograph GC7820 (manufactured by Agilent Technologies, detector: FID). The total amount of butadiene was calculated from the total peak area obtained and the absolute calibration curve prepared in advance, and this was used as the rubber content.
The measurement conditions are as follows.

≪Measurement conditions≫
・ Heating (590 ℃ -5sec)
・ Oven temperature (300 ℃)
・ Needle temperature (300 ℃)
Column (Inter Cap 5 (φ0.25 mm × 30 m (film thickness 0.25 μm): GL Sciences Inc.)
・ Temperature condition (After holding at 50 ° C. for 0.5 minutes, the temperature is raised to 200 ° C. at 10 ° C./minute, then raised to 320 ° C. at 20 ° C./minute and held at 320 ° C. for 0.5 minutes)
・ Carrier gas (He)
・ He flow (25ml / min)
・ Inlet pressure (100 KPa)
・ Inlet temperature (300 ℃)
・ Detector temperature (300 ℃)
・ Split ratio (1/30)
A standard sample for preparing a calibration curve is POLYSCIENCES. INC / St / BD = 85/15 (CAT # 07073) resin was used.

(Master Badge)
The following materials were prepared in advance in producing a polyether-based polymer masterbatch used for producing thermoplastic foamable resin particles for evaluation.

(A) Polyethylene glycol masterbatch A1: General purpose polystyrene (GPPS) manufactured by Toyo Styrene Co., Ltd., 90 parts by weight of “Toyostyrene HRM10N”, polyethylene glycol manufactured by Sanko Chemical Co., Ltd., “Sanconol PEG200-50T” (molecular weight Mn : 200) was blended in an amount of 10 parts by mass, melt kneaded at an extrusion temperature of 200 ° C., and discharged as a rod-shaped molded body. The discharged molded body was water-cooled, and a granular master batch was produced using a pelletizer.
A2: General-purpose polystyrene (GPPS) manufactured by Toyo Styrene Co., Ltd., 90 parts by mass of Toyo Styrol HRM10N, blended with 10 parts by mass of polyethylene glycol manufactured by Nippon Oil & Fats Co., Ltd., and trade name “PEG # 300” (molecular weight Mn: 300) A polyethylene glycol master batch was produced in the same manner as in A1 except that.
A3: Polypropylene manufactured by Borealis, trade name “Daploy WB-135”, 90 parts by mass, except for blending 10 parts by mass of polyethylene glycol manufactured by Nippon Oil & Fats, Inc., trade name “PEG # 1500” (molecular weight Mn: 1500) A polyethylene glycol master batch was prepared in the same manner as in A1.
A4: A polyethylene glycol masterbatch was prepared in the same manner as A1, except that polyethylene glycol manufactured by Nippon Oil & Fats Co., Ltd., trade name “PEG # 2000” (molecular weight Mn: 2000) was used as polyethylene glycol.
A5: General-purpose polystyrene (GPPS) manufactured by Toyo Styrene Co., Ltd., 80 parts by mass of product name “Toyostyrene HRM10N”, 10 parts by mass of polyethylene glycol manufactured by Sanko Chemical Co., Ltd. and product name “Sanconol PEG200-50T” (molecular weight Mn: 200) 10 parts by mass of 3M Lithium bistrifluoromethanesulfonimide, trade name “HQ-115” was blended, melt kneaded at an extrusion temperature of 200 ° C., and discharged as a rod-shaped molded body. The discharged molded body was water-cooled, and a granular master batch was produced using a pelletizer.

(B) Polypropylene glycol masterbatch B1: General-purpose polystyrene (GPPS) manufactured by Toyo Styrene Co., Ltd., trade name “Toyostyrene HRM10N” MFR 5.6 g / min (condition K of JIS K 7210) 90 parts by mass, manufactured by Sanyo Chemical Industries 10 parts by mass of polypropylene glycol and trade name “New Pole PP1200” (molecular weight Mn: 1150) were blended, melt-kneaded at an extrusion temperature of 200 ° C., and discharged as a rod-shaped molded body. The discharged molded body was water-cooled, and a granular master batch was produced using a pelletizer.

[Example 1]
(Preparation of foamable thermoplastic resin particles)
Polyether olefin block copolymer containing Na dodecylbenzenesulfonate as an ion conductive polymer type antistatic agent for 82 parts by mass of Toyostyrene Co., Ltd., general-purpose polystyrene resin (GPPS), trade name “Toyostyrene HRM26” 12 parts by mass (trade name “Peletron HS”, manufactured by Sanyo Chemical Industries, Ltd.) and 6 parts by mass of polyethylene glycol masterbatch (A1) are blended. MAX401-2HP (trade name) was added so as to be 0.5 parts by mass, and this was uniformly mixed in advance with a tumbler mixer and then supplied to a single screw extruder having a diameter of 90φ (L / D = 35). Melt kneading was performed with the single screw extruder. For this melt kneading, the maximum temperature in the extruder is set to 220 ° C., the kneaded resin is melted to obtain a molten resin, and a foaming agent (isopentane is used so that the ratio to 100 parts by mass of the molten resin is 5.0 parts by mass. : Normal pentane = 2: 8 mixture) Press-fitted from the middle of the extruder.
Then, while cooling so that the resin temperature at the front end of the extruder is 180 ° C., the molten resin is moved to the front end side of the extruder from this foaming agent press-fitting point, and the molten resin and the foaming agent are moved during the movement. Further kneading.
Next, a molten resin containing a foaming agent is conveyed to a granulation die through a diverter (extruder-die connection portion: maintained at a temperature of 185 ° C.) provided at the tip of the extruder, and the granulation die Melted in a chamber in which cooling water at 40 ° C circulates through eight circular plates (diameter having 25 nozzles with a diameter of 0.6 mm and a land length of 3.0 mm) arranged circumferentially on the die. The resin was extruded at a discharge rate of 150 kg / h.
Then, a high-speed rotary cutter having 10 rotary blades rotating along the place where the eye plate is installed is arranged on the chamber side, and the molten resin extruded from the nozzle and cooled by the cooling water is 3000 times per minute. Was cut with the rotary blade rotated at a rotational speed of, and dehydrated and dried to produce substantially spherical expandable polystyrene resin particles.

(Preparation of pre-expanded particles (1))
The foamable polystyrene resin particles are allowed to stand at 20 ° C. for 1 day, and then 0.1 parts by mass of 12-hydroxystearic acid triglyceride is added to and mixed with 100 parts by mass of the expandable polystyrene resin particles to obtain resin particle surfaces. After coating, it is put into a small batch type pre-foaming machine (internal volume 40L) and heated with steam (about 100 ° C.) with a blowing pressure of 0.05 MPa (gauge pressure) while stirring, Ten times (bulk density: 0.1 g / cm ³ ) pre-expanded particles were prepared.

(Fabrication molding production (1))
The pre-expanded particles were aged at 23 ° C. for 1 day, and then using an automatic molding machine (ACE-3SP2 model, manufactured by Sekisui Koki Co., Ltd.) equipped with a mold having an internal dimension of 400 × 300 × 30 mm, A bead-foamed molded article having an expansion ratio of 10 times (density 0.1 g / cm ³ ) was produced by in-mold molding under molding conditions.
<Molding conditions (ACE3-SP2)>
Molding vapor pressure: 0.08 MPa (gauge pressure)
Mold heating: 5 seconds One heating: 15 seconds Reverse one heating: 5 seconds Double-sided heating: 20 seconds Water cooling: 300 seconds Set extraction surface pressure: 0.02 MPa

[Evaluation method]
About the foaming molding of Example 1 manufactured as mentioned above, <surface specific resistance value> and <quantification of the polyether type compound in a foaming molding> were performed as follows. The results are shown in Table 1.

<Surface specific resistance value>
The obtained foamed molded article was measured for the value of surface resistivity by the method described in JIS K 6911: 1995 “General Test Method for Thermosetting Plastics”.
Specifically, a flat square test piece having a side of 10 cm and a thickness of 5 mm was left in an atmosphere of a temperature of 22 ° C. and a humidity of 60% for 24 hours, and then tested in an environment of a temperature of 22 ° C. and a humidity of 60%. Using an apparatus (manufactured by Advantest Corp., digital ultra-high resistance / microammeter R8340 and resiliency chamber R12702A), an electrode was crimped to the test piece with a load of about 30 N and a voltage of 500 V was applied for 1 minute. The subsequent resistance value was measured and calculated by the following equation (a).
ρs = π (D + d) / (D−d) × Rs (a)
However,
ρs: Surface resistivity (Ω / □)
D: Inner diameter (cm) of the annular electrode on the surface (7 cm for the resiliency chamber R12702A)
d: outer diameter (cm) of inner circle of surface electrode (5 cm for resiliency chamber R12702A)
Rs: Surface resistance (Ω)
Respectively.
Moreover, the measurement was implemented 3 times, each arithmetic mean value was calculated | required, and the following reference | standard evaluated.
Excellent (◎): Surface resistivity value is less than 5 × 10 ⁹ Ω / □ Good (◯): Surface resistivity value is 5 × 10 ⁹ Ω / □ or more and less than 7 × 10 ⁹ Ω / □ Effective (△): Surface resistivity value is 7 × 10 ⁹ Ω / □ or more, less than 1 × 10 ¹⁰ Ω / □ Defect (×): Surface resistivity value is 1 × 10 ¹⁰ Ω / □ or more

<Quantification of polyether-based compound in foam molded article>
(Extraction method)
Measurement method: 10.0 g of a sample was weighed into a 50 mL conical flask with a lid. Add about 20 mL of distilled water and leave it for one day. After filtration with 5A filter paper, the filtrate (distilled water) was evaporated to dryness. Methanol for HPLC was added to the obtained evaporated dry product and subjected to ultrasonic extraction. The extract was made up in a 20 mL volumetric flask, filtered through an aqueous 0.20 μm chromatodisc, and subjected to HPLC measurement.
(HPLC analysis (quantitative method))
Measuring device: Liquid chromatograph LC-10Avp (manufactured by Shimadzu Corporation)
Column: TSKgel ODS-80TS QA 4.6 * 150 (manufactured by TOSOH)
Measurement conditions: column temperature (40 ° C.), mobile phase (methanol), mobile phase flow rate (0.7 mL / min), pump temperature (room temperature), measurement time (10 min), detection (evaporation light scattering), injection volume (50 μL) )
Detector: Evaporative light scattering detector ELSD-2000 (manufactured by Altech)
Drift Tube temp. (60 ° C.), GAS Flow (1.6 mL / min), GAIN = 1 (impactor = off)

[Example 2]
Polyester ester amide block copolymer (manufactured by Sanyo Kasei Kogyo Co., Ltd.) containing dodecylbenzenesulfonic acid Na as an ion conductive polymer type antistatic agent for PS Japan Co., Ltd., HIPS, 64 parts by mass of “E641N”. , Trade name “Pelestat NC6321”) and 6 parts by mass of polyethylene glycol masterbatch (A1), and MAX401-2HP (trade name) manufactured by Takehara Chemical Co., Ltd. as a foam nucleating agent for 100 parts by mass of the resin. ) Was added so as to be 0.5 parts by mass, in the same manner as in Example 1, foamable thermoplastic resin particles, pre-foamed particles, and foamed molded products were produced, and the same was true for the obtained foamed molded products. Evaluated. The results are shown in Table 1.

[Example 3]
Polyether olefin block copolymer containing Na dodecylbenzene sulfonate (manufactured by Sanyo Kasei Kogyo Co., Ltd.) as an ion conductive polymer type antistatic agent with respect to 61 parts by mass of PS Japan Co., Ltd., HIPS and trade name “E641N” 15 parts by mass of “Peletron PVH” (trade name) and 24 parts by mass of polyethylene glycol masterbatch (A2) are mixed. The foamed thermoplastic resin particles, the pre-foamed particles and the foamed molded product were prepared in the same manner as in Example 1 except that 0.5 parts by mass was added. evaluated. The results are shown in Table 1.

[Example 4]
(Preparation of foamable thermoplastic resin particles)
Polyether ester amide block copolymer containing Na dodecylbenzenesulfonate as an ion conductive polymer type antistatic agent with respect to polypropylene manufactured by Borealis, trade name “Daploy WB-135”, 86.4 parts by mass ( 10 parts by mass of Sanyo Kasei Kogyo Co., Ltd., trade name “Pelestat 230”) and 3.6 parts by mass of polyethylene glycol masterbatch (A3) were added. After blending 0.5 parts by mass of MAX401-2HP (trade name) and 0.2 parts by mass of Hydrocerol HK manufactured by Boehringer, the mixture was uniformly mixed in a tumbler mixer in advance, and the diameter was 90φ (L / D = 35) was supplied to a single screw extruder and melt kneaded with the single screw extruder. For this melt-kneading, the maximum temperature in the extruder is set to 250 ° C. and the kneaded resin is melted, and then the ratio of the foaming agent (isopentane) extruder is 6 parts by mass with respect to 100 parts by mass of the kneaded resin. Press-fitted from the middle.
Then, while cooling the resin so that the resin temperature at the leading end of the extruder is 195 ° C., the molten resin is moved to the leading end side of the extruder from the blowing agent press-fitting point, and the molten resin and the blowing agent are moved during the movement. Further kneading.
Next, a molten resin containing a foaming agent is conveyed to a granulation die through a diverter (extruder-die connection portion: maintained at a temperature of 200 ° C.) provided at the tip of the extruder, and the granulation die is used. Melted in a chamber in which cooling water at 40 ° C circulates through eight circular plates (diameter having 25 nozzles with a diameter of 0.6 mm and a land length of 3.0 mm) arranged circumferentially on the die. The resin was extruded at a discharge rate of 150 kg / h.
Then, a high-speed rotary cutter having 10 rotary blades rotating along the place where the eye plate is installed is arranged on the chamber side, and the molten resin extruded from the nozzle and cooled by the cooling water is 3000 times per minute. It was cut with the rotary blade rotated at a rotational speed of, and dehydrated and dried to produce substantially spherical expandable polypropylene resin particles.

(Preparation of pre-expanded particles (2))
Immediately after extruding the expandable polypropylene resin particles, 0.1 parts by mass of 12-hydroxystearic acid triglyceride is added to 100 parts by mass of the expandable polypropylene resin particles and mixed to coat the resin particle surface. It is put into a pressure-resistant pre-foaming machine and heated with steam (about 154 ° C.) with a blowing pressure of 0.44 MPa (gauge pressure) while stirring, so that the bulk foaming factor is 10 times (bulk density 0.1 g / cm ³ ). The pre-expanded particles were prepared.

(Internal pressure applied)
By leaving the pre-expanded particles obtained by the above method in a pressurized carbon dioxide gas of 1.5 kg / cm ² at room temperature for 3 days, carbon dioxide gas is introduced into the polypropylene resin pre-expanded particles having poor foaming agent retention. The foaming force at the time of molding was given by press-fitting and applying an internal pressure.

(Fabrication molding production (2))
Immediately after applying the pre-expanded particles to which the internal pressure was applied, the mold was molded under the following molding conditions using an automatic molding machine (DBO-0504VS manufactured by DABO) equipped with a mold having an internal dimension of 400 × 300 × 30 mm. A foam molded article having an expansion ratio of 10 times (density 0.1 g / cm ³ ) was produced by internal molding.
<Molding conditions (DPM-0504)>
Molding vapor pressure: 0.38 MPa (gauge pressure)
Mold heating: 5 seconds One side heating: 15 seconds Reverse one side heating: 10 seconds Double-sided heating: 20 seconds Water cooling: 300 seconds Set extraction surface pressure: 0.02 MPa

  About the obtained foaming molding, the same evaluation as Example 1 was performed. The results are shown in Table 1.

[Example 5]
Polyether ester amide block copolymer containing Na dodecylbenzenesulfonate as an ion conductive polymer type antistatic agent with respect to polypropylene manufactured by Borealis, trade name “Daploy WB-135”, 86.4 parts by mass ( Sanyo Kasei Kogyo Co., Ltd., trade name “Pelestat 230”) 10 parts by mass and polypropylene glycol masterbatch (B1) 3.6 parts by mass, Takehara Chemical as a foam nucleating agent for 100 parts by mass of the resin Pre-foaming in the same manner as in Example 4 except that MAX401-2HP (trade name) manufactured by the company was added to 0.5 parts by mass and Hydrocerol HK manufactured by Boehringer was added to 0.2 parts by mass. Particles and a foam-molded product were prepared, and the obtained foam-molded product was evaluated in the same manner. The results are shown in Table 1.

[Example 6]
Polyether ester amide block co-polymer containing Na-decylbenzenesulfonate as an ion conductive polymer type antistatic agent for 58 parts by mass of Toyo Styrene Co., Ltd., general-purpose polystyrene resin (GPPS), trade name “Toyostyrene HRM26” 30 parts by weight of coalescence (manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name “Pelestat NC6321”) and 12 parts by weight of polyethylene glycol masterbatch (A4) are blended. A foamable thermoplastic resin particle, pre-foamed particle, and foamed molded article were produced in the same manner as in Example 1 except that 0.540 parts by mass of MAX401-2HP (trade name) was added. The foamed molded product thus obtained was evaluated in the same manner. The results are shown in Table 1.

[Example 7]
Polyether ester amide block containing Na dodecylbenzene sulfonate as an ion conductive polymer type antistatic agent for 69.4 parts by mass of general-purpose polystyrene resin (GPPS) manufactured by Toyo Styrene Co., Ltd. and the trade name “Toyostyrene HRM26” Example 6 except that 30 parts by mass of a copolymer (manufactured by Sanyo Chemical Industries, Ltd., trade name “Pelestat NC6321”) and (A1) as a polyethylene glycol masterbatch were added to 0.6 parts by mass. In the same manner as above, expandable thermoplastic resin particles, pre-expanded particles, and foamed molded products were prepared, and the obtained foamed molded products were evaluated in the same manner. The results are shown in Table 1.

[Example 8]
Polyether ester amide block copolymer containing trifluoromethanesulfonic acid Li as an ion conductive polymer type antistatic agent for 79 parts by mass of general-purpose polystyrene resin (GPPS) manufactured by Toyo Styrene Co., Ltd. and trade name “Toyostyrene HRM26” Combined (Sanko Chemical Co., Ltd., trade name "Sanconol TBX-65" 15 parts by mass, polyethylene glycol masterbatch (A1) 6 parts by mass, Takehara as a foam nucleating agent for 100 parts by mass of the resin Expandable thermoplastic resin particles, pre-expanded particles, foam-molded as in Example 1 except that 0.5 parts by mass of MAX401-2HP (trade name) manufactured by Kagaku Co., Ltd. was added and no polyether polymer was added. A body was made and evaluated.

[Comparative Example 1]
Except that the polyether polymer was not added, expandable thermoplastic resin particles, pre-expanded particles, and foamed molded products were prepared in the same manner as in Example 1, and the obtained foamed molded products were evaluated in the same manner. The results are shown in Table 1.

From the results shown in Table 1, the foam molded articles produced in Examples 1 to 8 according to the present invention had a low surface specific resistance value and excellent antistatic performance.
On the other hand, Comparative Example 1 in which the same amount of the ion conductive polymer type antistatic agent as Example 1 was added, but no polyether compound was added, had a high surface resistivity and poor antistatic performance. It was.
However, Examples 2, 4 to 7 are reference examples.

[Example 9]
(Preparation of foamable thermoplastic resin particles)
Polyethylene containing Na dodecylbenzenesulfonate as an ion conductive polymer type antistatic agent with respect to 74 parts by mass of general-purpose polystyrene resin (GPPS) (trade name “Toyostyrene HRM26”) so as to have the composition shown in Table 2. 20 parts by mass of an ether ester amide block copolymer (trade name “Pelestat NC6321” manufactured by Sanyo Chemical Industries, Ltd.) and 6 parts by mass of a polyethylene glycol masterbatch (A1) were blended.
Next, with respect to 100 parts by mass of the thermoplastic resin, MAX401-2HP (trade name) manufactured by Takehara Chemical Co., Ltd. is added as a foam nucleating agent to 0.5 parts by mass, and a foaming agent injected from the middle of the extruder is added. Expandable thermoplastic resin particles were produced in the same manner as in Example 1 except that the amount was 6.0 parts by mass with respect to 100 parts by mass of the molten resin.
The rubber content contained in the thermoplastic resin of this example is 0% by mass.

(Preparation of pre-expanded particles)
The foamable polystyrene resin particles are allowed to stand at 20 ° C. for 1 day, and then 0.1 parts by mass of 12-hydroxystearic acid triglyceride is added to and mixed with 100 parts by mass of the expandable polystyrene resin particles to obtain resin particle surfaces. After coating, it is put into a small batch type pre-foaming machine (internal volume 40L) and heated with steam (about 100 ° C.) with a blowing pressure of 0.05 MPa (gauge pressure) while stirring, Pre-expanded particles of 10 times (bulk density 0.10 g / cm ³ ) and 40 times (bulk density 0.025 g / cm ³ ) were prepared.

(Production of foamed molded product)
After the pre-expanded particles were aged at 23 ° C. for 1 day, the following molding was performed using an automatic molding machine (Sekisui Koki Seisakusho, ACE-3SP2 model) equipped with a mold having an internal dimension of 400 × 300 × 30 mm. In-mold molding was performed under the conditions to produce bead foam moldings having a foaming magnification of 10 times (density 0.10 g / cm ³ ) and 40 times (density 0.025 g / cm ³ ).
<10 times molded product molding conditions (ACE3-SP2)>
Molding vapor pressure: 0.08 MPa (gauge pressure)
Mold heating: 5 seconds One heating: 15 seconds Reverse one heating: 5 seconds Double-sided heating: 20 seconds Water cooling: 300 seconds Set extraction surface pressure: 0.02 MPa
<40 times molded product molding conditions (ACE3-SP2)>
Molding vapor pressure: 0.08 MPa (gauge pressure)
Mold heating: 3 seconds One heating: 14 seconds Reverse one heating: 4 seconds Double-sided heating: 10 seconds Water cooling: 10 seconds Set extraction surface pressure: 0.03 MPa

  About the obtained foaming molding, it carried out similarly to Example 1, and measured the surface specific resistance value and the amount of polyether compounds in a foaming molding. In addition, <maximum foamability evaluation of pre-expanded particles>, <40-fold foamability evaluation>, and <overall evaluation> described later were performed. The results are shown in Table 2.

<Evaluation of maximum foamability of pre-expanded particles>
The maximum bulk foaming factor (maximum bulk foaming factor) obtained by weighing 2.0 g of the sample and heating it with steam (100 ° C.) having a blowing pressure of 0.05 MPa (gauge pressure) was measured.
In the present invention, the bulk expansion ratio of the pre-expanded particles refers to a value obtained by the following measurement method after measuring the bulk density in accordance with JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. .

≪Bulk expansion ratio of pre-expanded particles≫
First, pre-expanded particles are filled in a graduated cylinder to a scale of 500 cm ³ . However, the graduated cylinder was visually observed from the horizontal direction, and the filling operation was completed if even one pre-expanded particle reached the scale of 500 cm ³ . Next, the mass of the pre-expanded particles filled in the graduated cylinder was weighed with two significant figures after the decimal point, and the mass was defined as W (g). The bulk density of the pre-expanded particles was calculated by the following formula.
Bulk density (g / cm ³ ) = W / 500
Next, the bulk expansion ratio of the pre-expanded particles was calculated by the following formula.
Bulk foam multiple (times) = 1 / bulk density (g / cm ³ )

<40 times foam moldability evaluation>
A flat foam molded body having a length of 400 mm, a width of 300 mm, and a thickness of 30 mm was molded, and the appearance of the molded body was evaluated according to the following evaluation criteria.
≪Evaluation criteria≫
(Double-circle): A foaming molding does not shrink | contract but an external appearance is very favorable.
○: Although slight shrinkage is observed in the foamed molded article, the appearance is good.
(Triangle | delta): A big shrinkage is seen by a foaming molding, and an external appearance is bad.
X: Significant shrinkage is observed in the foamed molded product, and remarkable deformation is observed in the appearance.

<Comprehensive evaluation>
Based on the results of <40-fold molded body surface specific resistance value> and <40-fold foam moldability evaluation>, evaluation was performed according to the following evaluation criteria.
A: Both surface resistivity and formability are evaluated as A.
○: The surface resistivity value is Δ or more and the moldability is ○ or more.
(Triangle | delta): It is evaluation whose surface specific resistance value is more than (triangle | delta), and moldability is (triangle | delta) or less.
X: The surface resistivity value is x evaluation.

[Example 10]
It replaces with 74 mass parts of "Toyostyrene HRM26", and is the same as Example 9 except having used 18 mass parts of HIPS (brand name "E641N") by PS Japan, and 56 mass parts of "Toyostyrene HRM26". Thus, expandable thermoplastic resin particles, pre-expanded particles, and foamed molded articles were produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 1.4% by mass.

[Example 11]
In the same manner as in Example 9, except that 74 parts by mass of “Toyostyrene HRM26” was used, 39.7 parts by mass of “E641N” and 34.3 parts by mass of “Toyostyrene HRM26” were used. Resin particles, pre-expanded particles, and foamed molded articles were prepared. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 3.0% by mass.

[Example 12]
In place of 74 parts by mass of “Toyostyrene HRM26”, 55.6 parts by mass of “E641N” and 18.4 parts by mass of “Toyostyrene HRM26” were used in the same manner as in Example 9, except that foamable thermoplasticity was used. Resin particles, pre-expanded particles, and foamed molded articles were prepared. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 4.2% by mass.

[Example 13]
Expandable thermoplastic resin particles, pre-expanded particles, and foamed molded articles were produced in the same manner as in Example 9 except that 74 parts by mass of “E641N” was used instead of 74 parts by mass of “Toyostyrene HRM26”. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 5.6% by mass.

[Example 14]
Expandable thermoplastic resin particles and pre-expanded particles in the same manner as in Example 9 except that 74 parts by mass of “Toyostyrene HRM26”, PS Japan Co., Ltd., HIPS, and 74 parts by mass of the trade name “H758K” were used. A foamed molded product was produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 7.0% by mass.

[Example 15]
Instead of using 74 parts by mass of “Toyostyrene HRM26”, 70 parts by mass of “Toyostyrene HRM26” and 4 parts by mass of styrene-butadiene copolymer (trade name “Tufprene A” manufactured by Asahi Kasei Kogyo Co., Ltd.) are used. In the same manner as in Example 9, expandable thermoplastic resin particles, pre-expanded particles, and a foam-molded article were produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 3.0% by mass.

[Example 16]
Except that 74 parts by mass of “Toyostyrene HRM26” was replaced by 44.7 parts by mass of “E6541N” and 39.3 parts by mass of “Toyostyrene HRM26”, and “Pelestat NC6321” was changed to 10 parts by mass. In the same manner as in Example 9, expandable thermoplastic resin particles, pre-expanded particles, and foamed molded articles were produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 3.0% by mass.

[Example 17]
Example except that 34.7 parts by mass of “E6541N” and 29.3 parts by mass of “Toyostyrene HRM26” were used instead of 74 parts by mass of “Toyostyrene HRM26”, and “Pelestat NC6321” was changed to 30 parts by mass. In the same manner as in Example 9, expandable thermoplastic resin particles, pre-expanded particles, and foamed molded articles were produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 3.0% by mass.
However, Example 17 is a reference example.

[Example 18]
Expandable thermoplastic resin particles in the same manner as in Example 9 except that instead of 74 parts by mass of “Toyostyrene HRM26”, 62 parts by mass of “Toyostyrene HRM26” and 12 parts by mass of “Toughprene A”, Pre-foamed particles and foamed molded products were produced. About the obtained foaming molding, it evaluated similarly to Example 9, and shows the result in Table 2.
The rubber content contained in the thermoplastic resin of this example is 9.0% by mass.
In this example, since the maximum bulk expansion ratio of the pre-expanded particles was 35 times and a 40-fold molded body could not be produced, evaluation of the 40-fold foam moldability and the surface specific resistance value in the 40-fold molded body and overall synthesis No evaluation was performed.

[Comparative Example 2]
As in Example 9, except that 74 parts by mass of “Toyostyrene HRM26” and 6 parts by mass of the polyethylene glycol masterbatch (A1) were replaced by 40 parts by mass of “E641N” and 40 parts by mass of “Toyostyrene HRM26”. Expandable thermoplastic resin particles, pre-expanded particles, and foamed molded articles were prepared. The obtained foamed molded product was evaluated in the same manner as in Example 9, and the results are shown in Table 2.
The rubber content contained in the thermoplastic resin of this example is 3.0% by mass. Moreover, the quantity of the polyether type compound contained in the thermoplastic resin of this example is 0 mass%.

As shown in Table 2, in each of Examples 9 to 18 to which the present invention was applied, the evaluation of the surface specific resistance value of the 10-fold molded body was “Δ” to “い ず れ”. In comparison of Examples 9 to 15 and 18 (all of which 20 parts by mass of an antistatic agent was added), Examples 10 to 15 and 18 containing rubber were compared with Example 9 not containing rubber. The surface resistivity was low.
In the comparison of Examples 10 to 14, as the rubber content increased, the surface specific resistance value decreased, but the shrinkage of the 40-fold molded body increased.
In Examples 11 and 12, the appearance of the 10-fold and 40-fold molded bodies was excellent in antistatic performance in the 10-fold and 40-fold molded bodies.
In Example 15, the rubber content was adjusted to the same amount as in Example 11 with a styrene-butadiene copolymer, and the same evaluation results as in Example 11 were obtained.
In Example 16, the rubber content was the same as in Example 11, but the surface resistivity value was higher than that in Example 11 because the proportion of the antistatic agent was small.
In Example 17, the rubber content was the same as in Example 11, but since the ratio of the antistatic agent was large, the surface specific resistance value was lower than that in Example 11, and the antistatic performance was excellent. The maximum bulk expansion ratio of the pre-expanded particles was low.
In Example 18 in which the rubber content was 9% by mass, the surface specific resistance value of the 10-fold molded body was good, but the 40-fold foam moldability was “Δ”.
In Comparative Example 2, the rubber content in the thermoplastic resin was 3.0%, but since the polyether compound was not contained, the surface specific resistance value was “x”.

  The present invention relates to an expandable thermoplastic resin particle capable of producing an antistatic foam molded article used as an electronic component packaging material, an electronic component transport tray, or the like that requires antistatic performance and antistatic properties, and the production thereof. The present invention relates to a method, pre-expanded particles, a foamed molded product, and a resin composition for producing an antistatic resin molded product.

  DESCRIPTION OF SYMBOLS 1 Extruder (resin supply device), 2 dies, 3 Raw material supply hopper, 4 High pressure pump, 5 Foaming agent supply port, 6 Cutter, 7 Cutting chamber, 8 Water tank, 9 High pressure pump, 10 Dehydration dryer with solid-liquid separation function 11 Storage container.

Claims (11)

A thermoplastic resin, a foaming agent, an ion conductive polymer type antistatic agent containing an anionic surfactant, and one or more polyether compounds selected from polyethylene glycol and polypropylene glycol,
Containing 5 to 30 parts by mass of the ion conductive polymer antistatic agent with respect to 100 parts by mass of the thermoplastic resin;
Expandable thermoplastic resin particles comprising 0.5 to 3.0 parts by mass of the polyether-based compound with respect to 100 parts by mass of the thermoplastic resin.   The foamable thermoplastic resin particle according to claim 1, wherein the thermoplastic resin contains a rubber component.   The expandable thermoplastic resin particles according to claim 2, wherein the rubber content relative to the thermoplastic resin is 1.0 to 8.0 mass%.   The foamable thermoplastic resin according to any one of claims 1 to 3, wherein the anionic surfactant is an alkali metal salt of dodecylbenzenesulfonic acid or an alkali metal salt of trifluoromethanesulfonic acid. particle.   The expandable thermoplastic resin particle according to any one of claims 1 to 4, wherein the polyether compound is polyethylene glycol.   6. The foamable thermoplastic resin particles according to claim 5, wherein the polyethylene glycol has a number average molecular weight (Mn) in the range of 200 to 1500.   The foamable thermoplastic resin particle according to any one of claims 1 to 6, wherein the thermoplastic resin is a polystyrene-based resin or an impact-resistant polystyrene-based resin.   Pre-expanded particles obtained by heating and foaming the expandable thermoplastic resin particles according to any one of claims 1 to 7.   A foam-molded product obtained by filling the pre-expanded particles according to claim 8 into a cavity of a molding die and heating to form in-mold foam molding. A thermoplastic resin, an ion conductive polymer-type antistatic agent containing an anionic surfactant, and one or more polyether compounds selected from polyethylene glycol and polypropylene glycol,
Containing 5 to 30 parts by mass of the ion conductive polymer antistatic agent with respect to 100 parts by mass of the thermoplastic resin;
A resin composition for producing an antistatic resin molded product, comprising 0.5 to 3.0 parts by mass of the polyether compound with respect to 100 parts by mass of the thermoplastic resin. A foaming agent is press-fitted and kneaded into the thermoplastic resin melted in the resin supply device, and the molten resin containing the foaming agent is extruded into the cooling liquid directly from the small hole of the die attached to the tip of the resin supply device. In the method for producing expandable thermoplastic resin particles by a melt extrusion method of cutting the extrudate and cooling and solidifying the extrudate by contact with the cooling liquid,
100 parts by mass of the thermoplastic resin, 5 to 30 parts by mass of an ion conductive polymer antistatic agent containing an anionic surfactant, and one or more polyether compounds selected from polyethylene glycol and polypropylene glycol 0 Foaming thermoplastic resin particles, wherein the foaming agent is press-fitted and kneaded into a molten resin containing 5 to 3.0 parts by mass, and the foaming agent-containing molten resin is extruded from the small holes of the die. Manufacturing method.

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