JP5552112B2 - Expandable polystyrene resin particles for low-magnification molding and manufacturing method thereof, low-magnification foamed particles, low-magnification foam moldings and fume tube cushion materials, low-magnification foam moldings and fume tube cushioning material manufacturing methods - Google Patents

Description

The present invention has a high fusion rate between the foamed particles of the obtained foamed molded product when producing a low-polystyrene resin foamed molded product having a foaming factor of 1.5 to 20 times by an in-mold foam molding method. The present invention relates to an expandable polystyrene resin particle for low-magnification molding suitable for producing a low-magnification foam-molded article having excellent elongation between foam particles and high bending strength and compression strength. The low-magnification foam molded product obtained by foam-molding the foamable polystyrene resin particles for low-magnification molding is used in the field of civil engineering, such as cushion materials for fume pipes (concrete propelling pipes), and for building materials, such as floor base materials. It is suitably used in the field.
This application claims priority based on Japanese Patent Application No. 2009-37165 for which it applied to Japan on February 19, 2009, and uses the content here.

  Low-polystyrene resin foam molded products having a foaming factor of 1.5 to 20 times are produced by an in-mold foam molding method. In this method, the low-expansion pre-expanded particles obtained by pre-expanding the expandable polystyrene resin particles as unexpanded particles or at a low expansion ratio of 2.0 to 20 times the bulk expansion ratio are filled in the mold cavity. . And the particle | grains in a cavity are heated, foamed, and fuse | melted, and the low magnification polystyrene-type resin foaming molding of a desired shape is taken out from a type | mold. It is important to have high strength (bending strength, compressive strength, etc.) as the quality required for low-polystyrene resin foam moldings used mainly in the fields of civil engineering and building materials. is there. In particular, it is the most important quality for a cushion material for a fume pipe (concrete propulsion pipe).

Patent documents 1-4 are mentioned as conventional technology relevant to the present invention.
In Patent Document 1, an expandable styrene resin particle containing an easily volatile foaming agent and having a styrene monomer content of 1000 ppm or less is selected from fatty acid amide and fatty acid bisamide with respect to 100 parts by mass of the resin particles. The fatty acid amide and the fatty acid bisamide amine are covered with at least one kind of 0.01 part by weight or more and 0.5 part by weight or less and a fatty acid metal salt of 0.2 part by weight or more and 1.0 part by weight or less. Expandable styrenic resin particles having a value of 1 or less are disclosed. In the paragraph [0029], usable fatty acid amides are exemplified, and in the paragraph [0031], usable fatty acid bisamides are exemplified.

  Patent Document 2 discloses expandable styrene resin particles having a styrene monomer content of 1000 ppm or less, and 0.01 to 0.5 parts by mass of fatty acid amide and / or 100 parts by mass of resin particles. Or the expandable styrene-type resin particle for food containers formed by coat | covering the particle | grain surface with fatty-acid bisamide is disclosed.

  In Patent Document 3, a water dispersion of a foamed polystyrene resin particle is added to and mixed with a water dispersion of a fine powder and a water-insoluble lubricant previously dispersed with an anionic or cationic surfactant. A surfactant that is opposite to the surfactant is added to the mixed dispersion, and an amount sufficient to neutralize the surfactant brought in by the lubricant aqueous dispersion is added, and the resin particle surface is coated with the lubricant. A method for producing a lubricant-coated expandable polystyrene resin particle is disclosed. In that example, 1.0 g of 12-hydroxystearic acid triglyceride having an average particle diameter of 60 μm and 0.7 g of ethylenebisstearic acid amide having an average particle diameter of 70 μm are added as a lubricant to 1 kg of expandable polystyrene particles, Describes the application of a lubricant.

  Patent Document 4 describes a modification obtained by impregnating and polymerizing polyethylene resin particles with a styrene monomer and containing 50 to 80% by mass of a polystyrene resin component and 20 to 50% by mass of a polyethylene resin component. Disclosed is an expandable resin particle obtained by impregnating 100 parts by mass of a polystyrene resin resin with 7 parts by mass or more of a foaming agent containing 10 to 40% by mass of propane and 60 to 90% by mass of butane. Has been. The paragraph [0044] states that the surface of the expandable resin particles may be coated with 12-hydroxystearic acid triglyceride, stearic acid triglyceride, stearic acid amide, 12-hydroxystearic acid amide or the like as a fusion accelerator. Have been described.

JP 2004-315806 A JP 2003-20136 A Japanese Patent Publication No. 7-47664 JP 2008-274133 A

However, the conventional techniques disclosed in Patent Documents 1 to 4 described above have the following problems.
Patent Document 1 discloses that at least one selected from fatty acid amide and fatty acid bisamide as a fusion accelerator and fatty acid metal salt 0 as an agglomeration inhibitor with respect to 100 parts by mass of expandable styrene resin particles. And expandable styrene resin particles coated with 2 parts by weight. However, in the case of producing a low-magnification foamed molded article having a foaming factor of 1.5 to 20 times, the foamed molded article obtained by the combination of the fusion accelerator and the agglomeration preventing agent described in Patent Document 1 is obtained. Therefore, the fusion rate and elongation between the expanded particles become insufficient, and the strength of the low-magnification expanded molded article cannot be improved.

  Patent Document 2 is similar to Patent Document 1, in the case of producing a low-magnification foamed molded article having an expansion ratio of 1.5 to 20 times, the fusion accelerator and the agglomeration inhibitor described in Patent Document 2 With this combination, the fusion rate between the foamed particles and the elongation of the obtained foamed molded article are insufficient, and the strength of the low-magnification foamed molded article cannot be improved.

  The example of Patent Document 3 describes that 12-hydroxystearic acid triglyceride and ethylenebisstearic acid amide are added as a lubricant to the surface of expandable polystyrene particles, and the lubricant is applied to the particle surface. However, in the case of producing a low-magnification foamed molded article having a foaming factor of 1.5 to 20 times, the combination of lubricants described in Patent Document 3 reduces the fusion rate between the foamed particles of the obtained foamed molded article. For this reason, it is difficult to produce a low-strength foam molded body having high strength.

  Patent Document 4 aims to obtain a foam molded article having good mechanical strength using a recycled styrene-modified polyethylene resin, and does not produce a high-strength low-magnification foam molded article according to the present invention. Absent. In the examples, the case where the surface of the expandable resin particles is coated with 12-hydroxystearic acid triglyceride is exemplified, but there is no example where the surface of the expandable resin particles made of polystyrene resin is coated. Further, if the surface of the expandable resin particles made of polystyrene resin is coated with 12-hydroxystearic acid triglyceride alone, the fusion rate between the expanded particles of the obtained foamed molded product is lowered, It is difficult to produce a high low-magnification foamed molded product.

  The present invention has been made in view of the above circumstances, and has a high fusion rate between foam particles of a low-magnification foam molded product obtained by in-mold foam molding, excellent elongation between foam particles, and high bending strength and compression strength. An object of the present invention is to provide an expandable polystyrene resin particle for low-magnification molding suitable for producing a low-magnification foam molded article.

  In order to achieve the above object, the present invention consists of a polystyrene resin containing a foaming agent, and higher fatty acid amide 0 with respect to 100 parts by mass of expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm. Provided is an expandable polystyrene resin particle for low-magnification molding, wherein 0.02 to 2.5 parts by mass and 0.02 to 2.5 parts by mass of a higher fatty acid triglyceride are used together to coat the particle surface.

  The present invention also provides low-magnification foamed particles obtained by heating the foamable polystyrene resin particles for low-magnification molding and foaming them in a range of bulk foaming factor of 2.0 to 20 times.

  The present invention also provides the low-magnification foamable polystyrene resin particles or low-magnification foamed particles filled in the cavity of a molding machine having a cavity that matches a desired molding shape, and obtained by in-mold foam molding. A low-magnification foamed molded article having a foam expansion ratio in the range of 1.5 to 20 times is provided.

  Furthermore, this invention provides the cushion material for fume pipe | tubes in which the foaming magnification of the said low magnification foaming molding is in the range of 1.5-10 times.

  Moreover, this invention consists of a polystyrene-type resin containing a foaming agent, and higher fatty acid amide 0.02-2.5 with respect to 100 mass parts of expandable polystyrene-type resin particles which are in the range whose average particle diameter is 300 micrometers-2500 micrometers. By adding and mixing the mass part and 0.02 to 2.5 parts by mass of the higher fatty acid triglyceride, the higher fatty acid amide and the higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles, and the low-magnification molding is used. Provided is a method for producing expandable polystyrene resin particles for low-magnification molding to obtain expandable polystyrene resin particles.

  Further, the present invention comprises a polystyrene-based resin containing a foaming agent, and an aqueous dispersion of expandable polystyrene-based resin particles having an average particle diameter in the range of 300 μm to 2500 μm. Additive aqueous dispersion in which fatty acid triglyceride is dispersed with a surfactant is added, mixed, and then dehydrated and dried to obtain the above-described expandable polystyrene resin particles for low-magnification molding of the present invention. Provided is a method for producing conductive polystyrene resin particles.

  The present invention also includes a finely powdered higher fatty acid amide and a higher fatty acid in advance in an aqueous dispersion of expandable polystyrene resin particles comprising a polystyrene resin containing a foaming agent and having a particle diameter in the range of 850 μm to 2000 μm. An additive aqueous dispersion in which triglyceride is dispersed with an anionic or cationic surfactant is added and mixed, and then the surfactant opposite to the surfactant is added to the mixed dispersion, and the additive aqueous dispersion is added to the aqueous dispersion. By adding an amount sufficient to neutralize the surfactant contained, the higher fatty acid amide and the higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles, and the above-described low-magnification foaming property of the present invention A method for producing expandable polystyrene resin particles for low-magnification molding to obtain polystyrene resin particles is provided.

In the present invention, the low-magnification molding expandable polystyrene resin particles or the low-magnification foam particles are filled in the cavity of a molding machine having a cavity that matches a desired molding shape, and the foaming ratio is 1.5 to Provided is a method for producing a low-magnification foamed molded article, which is foam-molded in a mold within a range of 20 times.

  Furthermore, this invention provides the manufacturing method of the cushioning material for fume pipe | tubes which makes the foaming magnification of the said low magnification foaming molding in the range of 1.5-10 times.

The expandable polystyrene resin particles for low-magnification molding of the present invention have a higher fatty acid amide of 0.02 to 2.5 masses per 100 mass parts of expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm. Part and 0.02 to 2.5 parts by mass of higher fatty acid triglyceride are used together to cover the particle surface. As a result, the low-magnification foamed molded product obtained by in-mold foam molding of the low-magnification foamed particles obtained by foaming the low-magnification polystyrene resin particles for low-magnification molding is obtained as follows. The fusion rate and elongation between particles are good, and the bending strength and compressive strength are excellent. Therefore, the expandable polystyrene resin particles for low-magnification molding of the present invention can be used for producing a low-magnification foam molded article excellent in bending strength and compressive strength.
The low-magnification expanded particles of the present invention are obtained by heating the low-magnification molding expandable polystyrene resin particles and foaming them within the range of the bulk expansion ratio of 2.0 to 20 times. It can be used to produce a low-magnification foam molded article excellent in the above.
The low-magnification foam molded article of the present invention is obtained by in-mold foam-molding the low-magnification foamable polystyrene resin particles or low-magnification foam particles, and the foaming ratio is in the range of 1.5 to 20 times. Because it is a thing, it has good fusion rate and elongation between foamed particles, has excellent bending strength and compressive strength, and is used for civil engineering such as cushioning materials for fume pipes (concrete propelling pipes) that require high strength and long-term durability. It can be applied to the field of building materials such as floor base materials.
In the cushion material for a fume tube of the present invention, the low-magnification foamed molded product has a foaming ratio of 1.5 to 10 times, so that the fusion rate and elongation between the foamed particles are good, and the bending strength and compressive strength are improved. Excellent, especially high strength and long-term durability.

  The expandable polystyrene resin particles for low-magnification molding of the present invention are made of a polystyrene resin containing a foaming agent, and the average particle diameter is within a range of 300 μm to 2500 μm, with respect to 100 parts by mass of expandable polystyrene resin particles. It is characterized in that 0.02 to 2.5 parts by mass of higher fatty acid amide and 0.02 to 2.5 parts by mass of higher fatty acid triglyceride are used in combination to coat the particle surface.

  The polystyrene resin used as the base of the low-magnification expandable polystyrene resin particles of the present invention is mainly composed of polystyrene, and may be a homopolymer of styrene, α-methylstyrene, paramethylstyrene, Styrene derivatives such as t-butyl styrene and chlorostyrene, acrylic acid and methacrylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and cetyl methacrylate, and various types such as acrylonitrile, dimethyl fumarate and ethyl fumarate It may be a copolymer with a monomer. Moreover, you may use together bifunctional monomers, such as divinylbenzene and alkylene glycol dimethacrylate. In the present invention, a preferred polystyrene resin is a styrene homopolymer.

As a foaming agent contained in the expandable polystyrene resin particles, either a volatile foaming agent or a decomposable foaming agent may be used.
Examples of the volatile foaming agent include aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ethers, and ketones. Among these, examples of the aliphatic hydrocarbon include propane, butane (normal butane, isobutane), pentane (normal pentane, isopentane, etc.), and examples of the alicyclic hydrocarbon include cyclopentane, cyclohexane, and the like. Can be mentioned. Examples of the halogenated hydrocarbon include one or more of halogenated hydrocarbons such as trichlorofluoromethane, trichlorotrifluoroethane, tetrafluoroethane, chlorodifluoroethane, difluoroethane, and the like. Furthermore, examples of the ether include dimethyl ether and diethyl ether, and examples of the ketone include acetone and methyl ethyl ketone.
Examples of decomposable foaming agents include inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium nitrite, azide compounds, sodium borohydride, azodicarbonamide, barium azodicarboxylate, and dinitrosopentamethylene. Organic foaming agents such as tetramine are listed.
The said foaming agent may be used independently and may mix and use 2 or more types.

  In the present invention, the average particle diameter of the expandable polystyrene resin particles is in the range of 300 μm to 2500 μm, preferably in the range of 650 μm to 2500 μm, and more preferably in the range of 800 μm to 2000 μm. When the average particle diameter of the expandable polystyrene resin particles is less than the above range, the low-magnification expandable polystyrene resin particles produced based on the resin particles, or the low-expansion foam obtained by pre-expanding it. When the double-expanded particles are filled in the cavity of the molding machine and foamed in-mold to produce a low-magnification foamed molded product, the space between the particles is narrowed and the steam for heating is not distributed evenly. There is a possibility that the fusion rate of the foam molded article becomes non-uniform, and a low-magnification foam molded article having sufficient strength cannot be obtained. On the other hand, when the average particle diameter of the expandable polystyrene resin particles exceeds the above range, the mass of one particle becomes large, and it becomes difficult to transport the particles into the cavity or to uniformly fill the particles. Moreover, it becomes unsuitable for manufacture of the foam-shaped body of complicated shape.

  These expandable polystyrene resin particles have foaming aids, lubricants, anti-shrink agents, and antioxidants as necessary, as long as they do not affect the foaming properties of the resin particles and the mechanical strength of the resulting low-magnification foamed molded product. Various additives such as an agent, an antistatic agent, a flame retardant, an ultraviolet absorber, a light stabilizer, a colorant, an inorganic cell nucleating agent, and an inorganic filler may be added.

  The expandable polystyrene resin particles for low-magnification molding of the present invention have a higher fatty acid amide 0.02 to 2.5 parts by mass and a higher fatty acid triglyceride 0.02 to 2 parts per 100 parts by mass of the expandable polystyrene resin particles. The particle surface is coated in combination with 5 parts by mass. Here, “coating the particle surface” means that the additive of the higher fatty acid amide and the higher fatty acid triglyceride may be attached or impregnated in any state on the surface of the expandable polystyrene resin particles. That is, any one of various bonding states from the state in which the fine powder of the additive is weakly adhered to the surface of the resin particle to the state in which the additive is completely impregnated in the surface layer of the resin particle. Also means good.

Examples of the higher fatty acid amide as one of the additives include capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, lignoceric acid amide, 12 -Hydroxy stearic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide and the like. Among these, stearic acid amide and palmitic acid amide are preferable.
In the present invention, “higher fatty acid amide” does not include fatty acid bisamides such as ethylene bisstearic acid amide.
The coating amount of the higher fatty acid amide is in the range of 0.02 to 2.5 parts by mass with respect to 100 parts by mass of the expandable polystyrene resin particles. Preferably it is in the range of 0.02-1.5 parts by mass, more preferably in the range of 0.03-1.0 parts by mass, most preferably in the range of 0.05-0.40 parts by mass. It is. When the coating amount is less than 0.02 parts by mass, in the low-magnification foam molded article produced by the in-mold foam molding described above, the fusion between the foamed particles deteriorates, and a high-strength low-magnification foam molded article is obtained. It becomes impossible. On the other hand, even if the coating amount exceeds 2.5 parts by mass, the fusion is deteriorated, and a high-strength low-magnification foam molded article cannot be obtained.

As the higher fatty acid triglyceride which is the other additive, it can be appropriately selected from various triglycerides containing a fatty acid having 10 or more carbon atoms. For example, vegetable oils such as olive oil, rapeseed oil, soybean oil, cottonseed oil, pork fat And synthetic / semi-synthetic oils and fats such as beef tallow, animal fats and oils, stearic acid triglyceride, 12-hydroxystearic acid triglyceride and palmitic acid triglyceride. Among these, 12-hydroxystearic acid triglyceride is preferable from the viewpoint of chemical stability.
The coating amount of the higher fatty acid triglyceride is in the range of 0.02 to 2.5 parts by mass with respect to 100 parts by mass of the expandable polystyrene resin particles. Preferably it exists in the range of 0.02-1.5 mass part, More preferably, it exists in the range of 0.06-0.50 mass part. When the coating amount is less than 0.02 parts by mass, in the low-magnification foam molded article produced by the above-described in-mold foam molding, the expansion of the foam particles is deteriorated, the number of gaps between the foam particles is increased, and the appearance is poor. In addition, a high-strength low-magnification foamed molded article cannot be obtained. On the other hand, even if the coating amount exceeds 2.5 parts by mass, the elongation is poor, the appearance is poor, and a high-strength, low-magnification foam molded article cannot be obtained.

  Next, the manufacturing method of the expandable polystyrene-type resin particle for low magnification molding which concerns on this invention is demonstrated.

(Manufacture of expandable polystyrene resin particles)
In the production method of the present invention, the expandable polystyrene resin particles can be produced using various conventionally known methods for producing foamed resin particles. Among these methods, (1) suspension polymerization method and (2) extrusion-water cutting method are preferable.

(1) Suspension polymerization method When producing polystyrene resin particles by the suspension polymerization method, polymerization is usually performed in an aqueous medium using a styrene monomer or a styrene monomer and another monomer as a material. A suspension polymerization method may be used, or a so-called suspension seed polymerization method in which a styrene monomer is added to a polystyrene resin seed particle (seed) dispersed in an aqueous medium and the seed particle is impregnated for polymerization. .

In the aqueous medium used in this suspension polymerization, as a dispersant, for example, a poorly water-soluble inorganic substance such as calcium phosphate, magnesium pyrophosphate, sodium pyrophosphate, magnesium oxide, a surfactant such as sodium dodecylbenzenesulfonate, etc. May be added.
Also, in this aqueous medium, foaming aids, lubricants, shrinkage inhibitors, antioxidants, antistatic agents, flame retardants, ultraviolet absorbers, light stabilizers, colorants, inorganic cell nucleating agents, inorganic fillers, etc. Various additives may be added.

The polymerization initiator used in this suspension polymerization is not particularly limited as long as it is conventionally used in this kind of polymerization, and examples thereof include benzoyl peroxide, di-t-butyl peroxide, and t-butyl peroxide. Benzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl-peroxy-2 -Ethyl hexyl carbonate etc. are mentioned, It may be used independently or 2 or more types may be used together.
If the amount of the polymerization initiator added to the aqueous medium is small, it takes too much time to polymerize the styrenic monomer. On the other hand, when there is much quantity of a polymerization initiator, the molecular weight of the polystyrene-type resin obtained will fall. The amount of the polymerization initiator is preferably 0.1 to 2 parts by mass, more preferably 0.2 to 0.8 parts by mass with respect to 100 parts by mass of the styrene monomer used.

After the various materials described above are placed in the reaction vessel, suspension polymerization is performed by heating to a temperature above which the styrene monomer starts to polymerize.
After completion of suspension polymerization, the obtained polystyrene resin particles are taken out from the reaction vessel, washed, dried, and further screened for polystyrene resin particles having an average particle diameter of 300 μm to 2500 μm by a method such as sieving. Collect.

Next, the polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm are impregnated with a foaming agent to produce expandable polystyrene resin particles.
As a procedure for impregnating the polystyrene resin particles with the foaming agent, a known procedure is used. Specifically, the polystyrene resin particles, the dispersant and the water are supplied into the autoclave and agitated. There is a method in which a dispersion liquid is produced by dispersing system resin particles in water, a foaming agent is pressed into the dispersion liquid, and the foaming agent is impregnated into the particles. The dispersant is not particularly limited, and examples thereof include poorly water-soluble inorganic substances such as calcium phosphate, magnesium pyrophosphate, sodium pyrophosphate, and magnesium oxide, and surfactants such as sodium dodecylbenzenesulfonate. Examples of the blowing agent preferably used here include propane, normal butane, isobutane, pentane, isopentane, cyclopentane, hexane and the like.

(2) Extrusion—Underwater cutting method In this method, an extruder provided with a foaming agent supply path for press-fitting a foaming agent into the molten resin while a die having a large number of nozzles for extruding the molten resin in a strand shape is attached to the tip. And an underwater cutting mechanism for cutting the molten resin extruded from the nozzle of this extruder in circulating water, and resin particle collection for separating and collecting the expandable polystyrene resin particles conveyed along with the flow of circulating water Expandable polystyrene resin particles are produced using a production apparatus having a mechanism.

  In this method, first, a polystyrene resin as a material and various additives that are added as necessary are put into an extruder, heated and melted and kneaded in the extruder, and a foaming agent is added to the molten resin. Press fit. The molten resin containing the foaming agent is extruded in a strand form from a number of nozzles of a die attached to the tip of the extruder. The extruded molten resin immediately comes into contact with the circulating water and is cut by the rotary blade while being suppressed in foaming, and is carried while being cooled along with the flow of the circulating water. Then, the circulating water and the expandable polystyrene resin particles are separated by the resin particle collecting mechanism, and the circulating water is circulated for use. The expandable polystyrene resin particles thus produced are dried and sieved as necessary to obtain expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm.

(Manufacture of expandable polystyrene resin particles for low-magnification molding)
Next, a higher fatty acid amide and a higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm, and the low-magnification foaming property according to the present invention. Polystyrene resin particles are produced.

  In the production method of the present invention, the following (1) to (3) are methods for attaching higher fatty acid amide and higher fatty acid triglyceride to the surface of expandable polystyrene resin particles and coating them with these additives. Can be mentioned. (1) Dry method (2) Wet method-1 (3) Wet method-2.

  (1) In the dry method, 0.02 to 2.5 parts by mass of a higher fatty acid amide and 0.02 to 2.5 parts by mass of a higher fatty acid triglyceride with respect to 100 parts by mass of an expandable polystyrene resin particle having an average particle size in the range of 300 to 2500 μm. By adding and mixing 02 to 2.5 parts by mass, the higher fatty acid amide and the higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles to obtain expandable polystyrene resin particles for low-magnification molding. At this time, the mixture of the resin particles and the additive may be appropriately heated. The additive of the higher fatty acid amide and the higher fatty acid triglyceride may be in the form of fine particles, or it is brought into contact with the surface of the resin particles in a state of being dissolved or dispersed in a small amount of an organic solvent. You may leave. Furthermore, you may add a small amount of adhesives (binder) which raises the adhesive force to the resin particle surface with these additives. According to this method, the total amount of the converted higher fatty acid amide and higher fatty acid triglyceride adheres to the surface of the expandable polystyrene resin particles.

  (2) In wet method-1, a fine powdery higher fatty acid amide and higher fatty acid triglyceride are preliminarily added to an aqueous dispersion of expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm. The additive aqueous dispersion dispersed in (1) is added and mixed, and then dehydrated and dried to obtain expandable polystyrene resin particles for low-magnification molding. The surfactant used here is not particularly limited and can be appropriately selected from various surfactants such as an anionic surfactant, a cationic surfactant, and a nonionic surfactant. For example, alkylbenzene sulfone can be used. Examples include acid salts. According to this method, about 50% of each of the added higher fatty acid amide and higher fatty acid triglyceride adheres to the surface of the expandable polystyrene resin particles.

  (3) In the wet method-2, a fine powdery higher fatty acid amide and a higher fatty acid triglyceride are previously mixed with an anion or cation in an aqueous dispersion of expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm. An additive aqueous dispersion dispersed with a surfactant is added and mixed, then a surfactant reverse to the surfactant is added to the mixed dispersion, and the surfactant contained in the additive aqueous dispersion is added. By adding an amount sufficient for neutralization, the higher fatty acid amide and the higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles to obtain low-magnification expandable polystyrene resin particles. The anionic or cationic surfactant used here is not particularly limited, and examples of the anionic surfactant include alkylbenzene sulfonate, and examples of the cationic surfactant include alkyldimethylbenzylammonium chloride. According to this method, about 50% of each of the added higher fatty acid amide and higher fatty acid triglyceride adheres to the surface of the expandable polystyrene resin particles.

  In the foamable polystyrene resin particles for low-magnification molding of the present invention produced as described above, higher fatty acid amide is added to 100 parts by mass of the expandable polystyrene resin particles having an average particle diameter in the range of 300 μm to 2500 μm. The particle surface is coated using 02 to 2.5 parts by mass and 0.02 to 2.5 parts by mass of a higher fatty acid triglyceride. As a result, the low-expandable polystyrene resin particles for low-magnification molding remain or are obtained by in-mold foam molding of the low-magnification foam particles obtained by low-expansion of the low-magnification foamable polystyrene resin particles. In addition, the low-magnification expanded molded article has good fusion rate and elongation between the expanded particles, and is excellent in bending strength and compressive strength. Therefore, the expandable polystyrene resin particles for low-magnification molding of the present invention can be used for producing a low-magnification foam molded article excellent in bending strength and compressive strength.

The “average particle diameter” of the expandable polystyrene resin particles for low-magnification molding of the present invention refers to those measured in the following manner. The method for measuring the average particle size is as follows.
Table 1 and Table 2 of ISO 565: 1990 (Tables 1 and 2 of ISO 565: 1990) were obtained using a low-tap type sieve shaker (manufactured by Iida Seisakusho) with 50 to 100 g of expandable polystyrene resin particles. ) Nominal aperture (auxiliary dimension) 4 mm, 3.35 mm, 2.8 mm, 2.36 mm, 2 mm, 1.7 mm, 1.4 mm, 1.18 mm, 1 mm, 850 μm, 710 μm, 600 μm, 500 μm, 425 μm Classification is carried out for 10 minutes with sieves of 355 μm, 300 μm, 250 μm, 212 μm and 180 μm. The sample mass on the sieve mesh is measured, and the particle diameter (median diameter) at which the cumulative mass is 50% is determined as the average particle size based on the cumulative mass distribution curve obtained from the result.
Further, the “bulk density” of the low-magnification expandable polystyrene resin particles of the present invention refers to those measured according to the method for measuring the “bulk density” of the low-magnification foam particles described later.

The low-magnification expanded particles according to the present invention are obtained by steam-heating the low-magnification foamable polystyrene resin particles of the present invention and foaming them within a range of a bulk expansion ratio of 2.0 to 20 times. The range of the bulk foaming factor is preferably 2.0 to 10 times, and more preferably 2.0 to 5 times.
When the bulk expansion ratio of the low expansion foam particles is less than the above range, the variation of the bulk expansion ratio is large, and uniform particles cannot be obtained. On the other hand, when the bulk expansion ratio of the low expansion foamed particles exceeds the above range, a low expansion foam molded article excellent in sufficient strength and long-term durability cannot be obtained.

The “bulk density” of the low-magnification expanded particles refers to those measured in the following manner. First, a 500 cm ³ graduated cylinder is prepared, and pre-expanded particles are filled in the graduated cylinder so as to be horizontal on the 500 cm ³ scale. The graduated cylinder is visually observed from the horizontal direction, and if any pre-expanded particles reach the scale of 500 cm ³ , the filling of the pre-expanded particles into the graduated cylinder is terminated at that point. Next, the mass of the pre-expanded particles filled in the graduated cylinder is weighed with two significant figures after the decimal point, and the mass is defined as W (g). Then, the bulk density of the pre-expanded particles is calculated by the following formula. Bulk density (g / cm ³ ) = W (g) / 500 (cm ³ )

Further, the “bulk foaming factor” of the low-magnification expanded particles is the reciprocal of the bulk density (1 / bulk density), and in the case of polystyrene resin, the low-magnification foamed particles having a bulk density of 0.2 g / cm ³ are Low expansion foam particles having a bulk expansion ratio of 5 times and a bulk density of 0.1 g / cm ³ have a bulk expansion ratio of 10 times.

  The low-magnification expanded particles according to the present invention are obtained by heating the foamable polystyrene resin particles for low-magnification molding and foaming them within the range of 1.5 to 20 times the bulk expansion ratio. It can be used to produce a low-magnification foam molded article excellent in the above.

  The low-magnification foam molded body according to the present invention is filled with the expandable polystyrene resin particles for low-magnification molding or the low-magnification foam particles in the cavity of a molding machine having a cavity that matches a desired molding shape, Obtained by in-mold foam molding. Moreover, the expansion ratio in that case is in the range of 1.5 to 20 times.

In this low-magnification foamed molded article, the expansion ratio is preferably in the range of 1.5 to 10 times, and more preferably in the range of 1.6 to 5 times. If the expansion ratio is within the above range, it can be applied to the field of civil engineering such as cushioning materials for fume pipes (concrete propulsion pipes), the field of building materials such as floor base materials, etc. An excellent low-magnification foamed article can be provided.
The “density” of the foamed molded product is measured by the method described in JIS K6767: 1999 “Foamed Plastics and Rubber—Measurement of Apparent Density”. That is, a test piece of 50 cm ³ or more (100 cm ³ or more in the case of semi-hard and soft materials) is cut so as not to change the original cell structure of the material, its mass (g) is measured, and calculated by the following formula: . Density (g / cm ³ ) = Test piece mass (g) / Test piece volume (cm ³ )
The “foaming multiple” of the foamed molded product is the reciprocal of the density (1 / density). In the case of polystyrene resin, the low-magnification expanded particles having a density of 0.2 g / cm ³ have a foaming multiple of 5 A low-fold expanded particle having a double density of 0.1 g / cm ³ has a expansion ratio of 10 times.

The low-magnification foam molded article of the present invention is obtained by in-mold foam-molding the low-magnification foamable polystyrene resin particles or low-magnification foam particles. Therefore, the fusion rate and elongation between the foamed particles are good, the bending strength and the compressive strength are excellent, and for civil engineering such as cushioning materials for fume pipes (concrete propulsion pipes) that require high strength and long-term durability. The present invention can be applied to the field and the field for building materials such as floor base materials.
The cushion material for a fume pipe (concrete propulsion pipe) according to the present invention is excellent in bending strength and compressive strength because the foaming ratio of the low-magnification foamed molded product is in the range of 1.5 to 10 times. Excellent long-term durability.
This fume pipe (concrete propulsion pipe) cushioning material preferably has a foaming factor of 1.6 to 5 times. When the expansion ratio is within the above range, a cushion material for a fume pipe (concrete propulsion pipe) that is particularly excellent in high strength and long-term durability can be provided.
The cushion material for a fume pipe (concrete propulsion pipe) can be manufactured by cutting out from a flat low-magnification foam molded body into a curved shape in accordance with the shape of the joint portion between the fume pipes. In addition, the cavity shape of the molding die set in the foam molding machine can be curved in advance, and can be manufactured by in-mold foam molding.

In the following examples, the effects of the present application will be described by taking as an example the case where low-magnification foamable polystyrene resin particles are produced by a dry method and a wet method.
[1] When producing expandable polystyrene resin particles for low-magnification molding by a dry method In Examples 1 to 14 and Comparative Examples 1 to 6 below, stearic acid is formed on the surface of the expandable styrene resin particles by a dry method. Both amide and 12-hydroxystearic acid triglyceride were coated (however, Comparative Examples 1 and 3 were either one) to produce low-magnification expandable polystyrene resin particles and low-magnification foam-molded articles. . By this method, the total amount of the added stearic acid amide and 12-hydroxystearic acid triglyceride adhered to the surface of the expandable polystyrene resin particles and was coated.

[Example 1]
In a 100 liter reactor, 44 kg of pure water, 800 g of tribasic calcium phosphate and 1.7 g of sodium dodecylbenzenesulfonate were added and stirred, and 110 g of benzoyl peroxide and 8 g of t-butylperoxybenzoate were dissolved and added to 42 kg of styrene. It was. The reactor was sealed and heated to 90 ° C., reacted for 5 hours, then heated to 125 ° C. over 1 hour, cooled after 1 hour, and cooled to room temperature. The obtained slurry was dehydrated and dried, and sieved to obtain polystyrene resin particles having an average particle diameter of 1400 μm.

  1.5 kg of pure water in a 5 liter reactor, 2.0 kg of polystyrene resin particles (average particle size 1400 μm, weight average molecular weight of about 300,000, residual monomer of about 2000 ppm) obtained by the above method, dodecylbenzenesulfonic acid 0.2 g of sodium and 7.0 g of magnesium pyrophosphate were added and suspended by stirring. Next, 0.5 kg of pure water prepared in advance, 0.1 g of sodium dodecylbenzenesulfonate and 9.5 g of toluene were stirred with a homomixer to prepare a suspension, and charged into the reactor. Next, 25 g of pentane and 18 g of butane were injected into the reactor at room temperature, heated to 120 ° C. and held for 5 hours, then cooled to room temperature and taken out to obtain expandable polystyrene resin particles.

Next, 2.0 kg of the obtained expandable styrene resin particles were put into a tumbler mixer (manufactured by Tokuju Kogakusha Co., Ltd., Kotobuki Mixwell W-20), and as a coating agent, 100 parts by mass of expandable styrene resin particles. , 0.02 parts by mass of stearic acid amide and 0.06 parts by mass of 12-hydroxystearic acid triglyceride were added, stirred, and bulk density 0.6 g coated with stearic acid amide and 12-hydroxystearic acid triglyceride A foamable polystyrene resin particle for low-magnification molding at / cm ³ was obtained.

Next, the mold cavity (200 mm × 150 mm × 15 mm) in which the expandable polystyrene resin particles for low-magnification molding obtained by the above-described method were set in a molding machine (ACE-3SP, manufactured by Sekisui Koki Co., Ltd.) Cavity for molding), heated with 0.08 MPa water vapor for 35 seconds, cooled, density 0.6 g / cm ³ , foaming factor 1.7 times, low magnification of dimensions 200 mm × 150 mm × 15 mm A foamed molded product was obtained.

  The following tests and evaluations were performed on this foamed molded product. The results are shown in Table 1.

<Fusion rate>
First, a cutting line having a depth of 1 mm was formed on an arbitrary surface of the low-magnification foam molded body using a cutter knife, and the low-magnification foam molded body was divided into two by hand or a hammer along the cutting line. Thereafter, in any 100 to 150 expanded particles exposed on the fracture surface of the low-magnification expanded molded article, the number of particles (a) broken in the expanded particles and the fracture at the thermal fusion interface between the expanded particles The number (b) of the particles being counted was counted, and the fusion rate of the low-magnification foamed molded product was calculated based on the following formula.
Fusion rate of foamed molded product (%) = 100 × number of particles (a) / (number of particles (a) + number of particles (b))
For the fusion rate, 70% or more was accepted and less than 70% was rejected.

<Elongation>
The surface of the low-magnification foamed molded product is observed, and the number (a) of the foamed particles within the range of 30 mm × 30 mm with no trace of the core vent (vapor hole) and between the foamed particles surrounded by at least three foamed particles The number of gaps (b) having a gap distance of 0.5 mm or more, respectively, and calculating the gap ratio of the low-magnification foamed molded product based on the following formula Was rated on a five-point scale. An evaluation of “4” or higher was regarded as acceptable for sufficient elongation, and an evaluation of “3” or lower was regarded as unacceptable for insufficient elongation.
Crevice ratio (%) = b / a × 1005: There is no gap between particles (gap ratio 0%). 4: The clearance ratio exceeds 0% and is less than 5%. 3: The clearance ratio is 5% or more and less than 20%. 2: The clearance ratio is 20% or more and less than 40%. 1: The clearance ratio is 40% or more.

[Example 2]
The low-magnification expandable polystyrene resin particles and the low-magnification moldable polystyrene resin particles in the same manner as in Example 1 except that the amount of stearic acid amide used for the production of the low-magnification expandable polystyrene resin particles was 0.03 parts by mass. A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 3]
Except that the addition amount of stearic acid amide used for the production of the low-magnification expandable polystyrene resin particles is 0.05 parts by mass, the low-magnification foamable polystyrene resin particles and A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 4]
Except that the addition amount of stearic acid amide used for the production of low-magnification expandable polystyrene resin particles was 0.07 parts by mass, the low-magnification foamable polystyrene resin particles and A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 5]
Except that the addition amount of stearic acid amide used for the production of low-magnification expandable polystyrene resin particles was 0.10 parts by mass, the low-magnification foamable polystyrene resin particles and A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 6]
Except that the addition amount of stearic acid amide used for the production of the low-magnification expandable polystyrene resin particles was 0.20 parts by mass, the low-magnification foamable polystyrene resin particles and A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 7]
The low-magnification expandable polystyrene resin particles and the low-magnification moldable polystyrene resin particles in the same manner as in Example 1 except that the amount of stearic acid amide used for the production of the low-magnification expandable polystyrene resin particles was 0.30 parts by mass. A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 8]
Except that the amount of stearic acid amide used for the production of the low-magnification expandable polystyrene resin particles was 0.40 parts by mass, the low-magnification foamable polystyrene resin particles and A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Example 9]
Implemented except that the addition amount of stearic acid amide used for the production of expandable polystyrene resin particles for low-magnification molding was 0.10 parts by mass and the addition amount of 12-hydroxystearic acid triglyceride was 0.02 parts by mass In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Example 10]
Implemented except that the addition amount of stearic acid amide used in the production of low-magnification expandable polystyrene resin particles was 0.10 parts by mass and the addition amount of 12-hydroxystearic acid triglyceride was 0.04 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Example 11]
Implemented except that the addition amount of stearic acid amide used for the production of expandable polystyrene resin particles for low-magnification molding was 0.10 parts by mass, and the addition amount of 12-hydroxystearic acid triglyceride was 0.10 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Example 12]
Implemented except that the addition amount of stearic acid amide used for the production of low-magnification expandable polystyrene resin particles was 0.10 parts by mass, and the addition amount of 12-hydroxystearic acid triglyceride was 0.20 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Example 13]
The addition amount of stearic acid amide used for the production of expandable polystyrene resin particles for low-magnification molding is 0.10 parts by mass, the addition amount of 12-hydroxystearic acid triglyceride is 0.06 parts by mass, and the others are carried out. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding were obtained. The obtained low-magnification moldable polystyrene resin particles were heated with steam at about 95 ° C. by a batch type foaming machine, and pre-foamed to a bulk density of 0.2 g / cm ³ and a bulk foaming factor of 5 times. The pre-expanded particles were left to stand at room temperature for about 1 day and aged, and then the pre-expanded particles were filled into a molding machine cavity (200 mm × 150 mm × 15 mm), heated with 0.08 MPa steam for 35 seconds, and cooled. Thus, a low-magnification foamed molded article having a density of 0.2 g / cm ³ , a foaming ratio of 5 times, and a size of 200 mm × 150 mm × 15 mm was obtained. This low-magnification foam molded article was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 14]
The addition amount of stearic acid amide used for the production of expandable polystyrene resin particles for low-magnification molding is 0.10 parts by mass, the addition amount of 12-hydroxystearic acid triglyceride is 0.06 parts by mass, and the others are carried out. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding were obtained. The obtained low-magnification foamable polystyrene resin particles for low-magnification molding were heated with steam at about 95 ° C. by a batch type foaming machine, and pre-foamed to a bulk density of 0.1 g / cm ³ and a bulk foaming factor of 10 times. The pre-expanded particles were left to stand at room temperature for about 1 day and aged, and then the pre-expanded particles were filled into a molding machine cavity (200 mm × 150 mm × 15 mm), heated with 0.08 MPa steam for 35 seconds, and cooled. As a result, a low-magnification foamed molded article having a density of 0.1 g / cm ³ , an expansion ratio of 10 times, and a size of 200 mm × 150 mm × 15 mm was obtained. This low-magnification foam molded article was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 15]
The average particle diameter of polystyrene resin particles used for the production of low-magnification expandable polystyrene resin particles is 800 μm, the addition amount of stearic acid amide is 1.0 part by mass, and the addition amount of 12-hydroxystearic acid triglyceride is Except that it was 0.50 parts by mass, the low-magnification foamable polystyrene resin particles and the low-magnification foam molded body were produced in the same manner as in Example 1, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Example 16]
Implemented except that the addition amount of stearic acid amide used for the production of low-magnification expandable polystyrene resin particles was 1.5 parts by mass, and the addition amount of 12-hydroxystearic acid triglyceride was 1.5 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 1]
Except that stearic acid amide was not added and only 0.06 parts by mass of 12-hydroxystearic acid triglyceride was added as an additive used for producing low-magnification expandable polystyrene resin particles. Thus, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 2]
The low-magnification expandable polystyrene resin particles and the low-magnification moldable polystyrene resin particles in the same manner as in Example 1 except that the amount of stearic acid amide used for the production of the low-magnification foamable polystyrene resin particles was 0.01 parts by mass. A low-magnification foamed molded article was produced and subjected to the same tests and evaluation as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
Example 1 except that 0.10 parts by mass of stearic acid amide was added and 12-hydroxystearic acid triglyceride was not added as an additive used for producing low-magnification expandable polystyrene resin particles. Similarly, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 4]
Implemented except that the addition amount of stearic acid amide used in the production of low-magnification expandable polystyrene resin particles was 0.10 parts by mass and the addition amount of 12-hydroxystearic acid triglyceride was 0.01 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 5]
As an additive used for the production of low-magnification expandable polystyrene resin particles, the addition amount of stearic acid amide is 0.10 parts by mass, and instead of 12-hydroxystearic acid triglyceride, 0.06 parts by mass of zinc stearate Except that it was added, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced in the same manner as in Example 1, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 6]
0.10 parts by mass of ethylenebisstearic acid amide instead of stearic acid amide and 0.06 parts by mass of 12-hydroxystearic acid triglyceride as an additive used for the production of low-magnification expandable polystyrene resin particles Except that it was added, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced in the same manner as in Example 1, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

[Comparative Example 7]
Implemented except that the addition amount of stearic acid amide used for the production of low-magnification expandable polystyrene resin particles was 3.0 parts by mass and the addition amount of 12-hydroxystearic acid triglyceride was 3.0 parts by mass. In the same manner as in Example 1, expandable polystyrene resin particles for low-magnification molding and a low-magnification foam-molded product were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 1.

  From the results of Table 1, the surface of the expandable polystyrene resin particles is 0.02 to 2.5 parts by mass of higher fatty acid amide and 0.02 to 2.5 parts by mass of higher fatty acid triglyceride with respect to 100 parts by mass of the resin particles. The low-magnification foamed molded products of Examples 1 to 16 according to the present invention produced by using low-magnification foamable polystyrene resin particles formed by coating in combination with each other have a fusion rate of 75% or more. Yes, the evaluation of elongation was 4 to 5, and had excellent strength and durability.

On the other hand, Comparative Example 1 which was not coated with stearic acid amide and coated with 0.06 parts by mass of 12-hydroxystearic acid triglyceride had a poor fusion rate of the low-magnification foamed molded article, and a molded article with sufficient strength was obtained. I couldn't.
Further, in Comparative Example 2 in which the coating amount of stearic acid amide was 0.01 parts by mass and less than the range of the present invention, the fusion rate of the low-magnification foam molded article was poor, and a molded article with sufficient strength could not be obtained. .
Further, in Comparative Example 3 in which 12-hydroxystearic acid triglyceride was not coated, although the fusion rate was improved, the elongation of the expanded particles was as bad as “2” in the five-step evaluation, and the number of gaps between the expanded particles was small. There were very many poor appearances, and a molded article with sufficient strength could not be obtained.
Further, in Comparative Example 4 in which the coating amount of 12-hydroxystearic acid triglyceride was less than 0.01 parts by mass and less than the range of the present invention, the elongation of the expanded particles was poor as “3” in the five-step evaluation, and the gap between the expanded particles And the appearance was poor, and a molded article with sufficient strength could not be obtained.
Further, in Comparative Example 5 in which zinc stearate was coated instead of 12-hydroxystearic acid triglyceride, both the fusion rate and elongation of the low-magnification foam molded article were deteriorated, and a molded article having sufficient strength could not be obtained. .
In Comparative Example 6 in which ethylene bis-stearic acid amide was coated instead of stearic acid amide, the evaluation of elongation was good, but the fusion rate was poor, and a molded article having sufficient strength could not be obtained.
Further, Comparative Example 7 in which the coating amount of stearic acid amide is 3.0 parts by mass and the coating amount of 12-hydroxystearic acid triglyceride is 3.0 parts by mass exceeds the range of the present invention. The ratio was poor and the elongation of the expanded particles was also as bad as “3” in a five-step evaluation. The number of gaps between the expanded particles was large and the appearance was poor, and a molded article with sufficient strength could not be obtained.

[2] When producing expandable polystyrene resin particles for low-magnification molding by a wet method In Examples 15 to 21 and Comparative Examples 7 to 9 below, stearic acid is applied to the surface of the expandable styrene resin particles by a wet method. Coating both amide and 12-hydroxystearic acid triglyceride (however, Comparative Example 7 was only 12-hydroxystearic acid triglyceride) Manufactured. By this method, about 50% of each of the added stearic acid amide and 12-hydroxystearic acid triglyceride adhered to the surface of the expandable polystyrene resin particles and was coated.

[Example 17] (Preparation of aqueous additive dispersion)
Put 300 mL of water in a 500 mL beaker, and 100 parts by mass of expandable polystyrene resin particles to be used later, 0.04 parts by mass of stearic acid amide, 0.12 parts by mass of 12-hydroxystearic acid triglyceride, and dodecylbenzenesulfonic acid 0.005 part by mass of sodium was added and dispersed using a stirrer to prepare an aqueous additive dispersion.

(Preparation of expandable polystyrene resin particles for low-magnification molding)
Next, 1.0 kg of the expandable polystyrene resin particles obtained in Example 1 and 650 mL of water were added to a 2 L beaker, and the additive aqueous dispersion was further added. And stirred for 5 minutes at 650 rpm. Next, this was dehydrated and dried to obtain low-magnification foamable polystyrene resin particles having a bulk density of 0.6 g / cm ³ .

Based on the low-magnification foamable polystyrene resin particles produced by the above-described method, in-mold foam molding was performed in the same manner as in Example 1, and the density was 0.6 g / cm ³ , the expansion ratio was 1.7 times, and the dimensions were A low-magnification foamed molded article of 200 mm × 150 mm × 15 mm was obtained. The obtained low-magnification foamed molded article was subjected to the same tests and evaluation as in Example 1. The results are shown in Table 2.

[Example 18]
Extensive polystyrene resin particles for low-magnification molding and low-magnification foam moldings in the same manner as in Example 15 except that the amount of stearic acid amide added to the additive aqueous dispersion was 0.06 parts by mass. The same test and evaluation as in Example 1 were performed. The results are shown in Table 2.

[Example 19]
Extensive polystyrene resin particles for low-magnification molding and low-magnification foam moldings in the same manner as in Example 15 except that the addition amount of stearic acid amide added to the additive aqueous dispersion was 0.10 parts by mass. The same test and evaluation as in Example 1 were performed. The results are shown in Table 2.

[Example 20]
Except that the addition amount of stearic acid amide added to the additive aqueous dispersion was 0.20 parts by mass, and the addition amount of 12-hydroxystearic acid triglyceride was 0.04 parts by mass, the same as in Example 15. Then, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 2.

[Example 21]
Except that the addition amount of stearic acid amide added to the additive aqueous dispersion was 0.20 parts by mass, and the addition amount of 12-hydroxystearic acid triglyceride was 0.04 parts by mass, the same as in Example 15. Then, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 2.

[Example 22]
Low-magnification foaming in the same procedure as in Example 15 except that 0.20 parts by mass of stearic acid amide and 0.12 parts by mass of 12-hydroxystearic acid triglyceride were prepared in the preparation of the additive aqueous dispersion. Polystyrene resin particles were obtained. The obtained low-magnification molding expandable polystyrene resin particles were heated with about 95 ° C. water vapor by a batch type foaming machine, and pre-expanded to a bulk density of 0.2 g / cm ³ and a bulk foaming factor of 5 times. The pre-expanded particles were left to stand at room temperature for about 1 day and aged, and then the pre-expanded particles were filled into a molding machine cavity (200 mm × 150 mm × 15 mm), heated with 0.08 MPa steam for 35 seconds, and cooled. Thus, a low-magnification foamed molded article having a density of 0.2 g / cm ³ , a foaming ratio of 5 times, and a size of 200 mm × 150 mm × 15 mm was obtained. The same test and evaluation as in Example 1 were performed on this low-magnification foamed molded product. The results are shown in Table 2.

[Example 23]
Low-magnification molding in the same procedure as in Example 15 except that 0.20 parts by mass of stearic acid amide and 0.12 parts by mass of 12-hydroxystearic acid triglyceride were prepared in the preparation of the additive aqueous dispersion. Expandable polystyrene resin particles were obtained. The obtained low-magnification expandable polystyrene resin particles were heated with steam at about 95 ° C. by a batch type foaming machine, and pre-expanded to a bulk density of 0.1 g / cm ³ and a bulk foaming factor of 10 times. The pre-expanded particles were left to stand at room temperature for about 1 day and aged, and then the pre-expanded particles were filled into a molding machine cavity (200 mm × 150 mm × 15 mm), heated with 0.08 MPa steam for 35 seconds, and cooled. As a result, a low-magnification foamed molded article having a density of 0.1 g / cm ³ , an expansion ratio of 10 times, and a size of 200 mm × 150 mm × 15 mm was obtained. The same test and evaluation as in Example 1 were performed on this low-magnification foamed molded product. The results are shown in Table 2.

[Comparative Example 8]
Low-magnification molding in the same manner as in Example 15 except that in the preparation of the additive aqueous dispersion, stearic acid amide was not added and only 12-hydroxystearic acid triglyceride was added at 0.12 parts by mass. The foamable polystyrene resin particles and the low-magnification foamed molded product were manufactured, and the same test and evaluation as in Example 1 were performed. The results are shown in Table 2.

[Comparative Example 9]
In the preparation of the additive aqueous dispersion, the low-magnification foamable polystyrene resin particles and the low-magnification foam molding were performed in the same manner as in Example 15 except that the addition amount of stearic acid amide was 0.02 parts by mass. The body was manufactured and the same test and evaluation as Example 1 were performed. The results are shown in Table 2.

[Comparative Example 10]
In the preparation of the additive aqueous dispersion, the same as in Example 15 except that the addition amount of stearic acid amide was 0.20 parts by mass and the addition amount of 12-hydroxystearic acid triglyceride was 0.02 parts by mass. Thus, expandable polystyrene resin particles for low-magnification molding and low-magnification foamed molded articles were produced, and the same tests and evaluations as in Example 1 were performed. The results are shown in Table 2.

  From the results of Table 2, even when [2] expandable polystyrene resin particles for low-magnification molding were produced by a wet method, as in the case of [1] dry method, Examples 17 to 23 according to the present invention. All of the low-magnification foamed molded articles had a fusion rate of 75% or more, an evaluation of elongation of 4 to 5, and had excellent strength and durability.

On the other hand, Comparative Example 8 which was not coated with stearic acid amide and coated with 0.06 part by mass of 12-hydroxystearic acid triglyceride had a poor fusion rate of the low-magnification foamed molded product, and a molded product with sufficient strength was obtained. I couldn't.
In Comparative Example 9 in which the coating amount of stearic acid amide was less than the range of the present invention, the fusion rate of the low-magnification foam molded article was poor, and a molded article having sufficient strength could not be obtained.
Further, in Comparative Example 10 in which the coating amount of 12-hydroxystearic acid triglyceride was less than the range of the present invention, the elongation of the expanded particles was bad as “3” of the five-step evaluation, the number of gaps between the expanded particles was large, and the appearance was poor In addition, a molded article having sufficient strength could not be obtained.

According to the expandable polystyrene resin particles for low-magnification molding of the present invention, the fusion rate between the foam particles of the low-magnification foam molded product obtained by in-mold foam molding is high, the elongation between the foam particles is excellent, and the bending A low-magnification expanded molded article having high strength and compressive strength can be produced. The low-magnification foam molded article of the present invention is suitably used in the field of civil engineering such as a cushion material for a fume pipe (concrete propulsion pipe), the field of building materials such as a floor base material, and the like.
The cushion material for a fume pipe of the present invention is suitably used as a cushion material for a fume pipe (concrete propulsion pipe).

Claims (9)

In the expandable polystyrene-based resin particles for low-magnification molding used for the production of a low-magnification foam molded product having a foaming factor of 1.5 to 20 times,
Higher fatty acid amide 0.02-2.5 parts by mass with respect to 100 parts by mass of expandable polystyrene resin particles comprising a polystyrene-based resin containing a foaming agent and having an average particle diameter in the range of 300 μm to 2500 μm. fatty acid triglyceride 0.0 from 6 to 2.5 parts by weight and the low-magnification molding expandable polystyrene resin particles in combination with, characterized by comprising coating the particle surface with.   Low-expanded foamed particles obtained by heating the expandable polystyrene resin particles for low-magnification molding according to claim 1 and foaming them in a range of bulk expansion ratio of 2.0 to 20 times.   The expandable polystyrene resin particles for low-magnification molding according to claim 1 or the low-magnification foamed particles according to claim 2 are filled into the cavity of a molding machine having a cavity that matches a desired molding shape, A low-magnification foam molded product obtained by inner foam molding and having a foaming ratio of 1.5 to 20 times.   A cushioning material for a fume tube, wherein the expansion ratio of the low-magnification expanded molded article according to claim 3 is in the range of 1.5 to 10 times. Higher fatty acid amide 0.02-2.5 parts by mass with respect to 100 parts by mass of expandable polystyrene resin particles comprising a polystyrene-based resin containing a foaming agent and having an average particle diameter in the range of 300 μm to 2500 μm. It was added and the fatty acid triglyceride 0.0 from 6 to 2.5 parts by weight, low magnification molded according to a higher fatty acid amide and a higher fatty acid triglyceride and claim 1 is adhered to the expandable polystyrene resin particles the surface by mixing Of expandable polystyrene resin particles for low-magnification molding to obtain expandable polystyrene resin particles for use.   An aqueous dispersion of expandable polystyrene resin particles comprising a polystyrene resin containing a foaming agent and having an average particle size in the range of 300 μm to 2500 μm is preliminarily interfaced with fine fatty acid amide and higher fatty acid triglyceride. Additive aqueous dispersion dispersed with an activator is added and mixed, and then dehydrated and dried to obtain expandable polystyrene resin particles for low-magnification molding according to claim 1. Manufacturing method.   An aqueous dispersion of expandable polystyrene resin particles consisting of a polystyrene resin containing a foaming agent and having an average particle size in the range of 300 μm to 2500 μm is prepared by anionic anion of fine fatty acid amide and higher fatty acid triglyceride in advance. Alternatively, an additive aqueous dispersion dispersed with a cationic surfactant is added and mixed, and then a surfactant reverse to the surfactant is added to the mixed dispersion, and the surfactant contained in the additive aqueous dispersion is mixed. The foamable polystyrene resin particles for low-magnification molding according to claim 1, wherein the higher fatty acid amide and the higher fatty acid triglyceride are adhered to the surface of the expandable polystyrene resin particles by adding an amount sufficient to neutralize the agent. A process for producing expandable polystyrene resin particles for low-magnification molding.   The expandable polystyrene resin particles for low-magnification molding according to claim 1 or the low-magnification foamed particles according to claim 2 are filled into the cavity of a molding machine having a cavity that matches a desired molding shape, and foamed. A method for producing a low-magnification foamed molded article, in which in-mold foam molding is performed within a range of a multiple of 1.5 to 20 times.   The manufacturing method of the cushion material for fume pipe | tubes which makes the expansion ratio of the low expansion | swelling expansion molded object of Claim 8 in the range of 1.5-10 times.