JP2010255395A - Expandable polystyrene resin particle for heat insulating material used for substrate material for roof, and heat insulating material for the substrate material for roof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expandable polystyrene resin particles having a heat resistance within ±0.5% of the dimensional change rate when heating at 90°C for 168 hours, having excellent thermal insulation property, and having excellent filling property into a cavity upon molding. <P>SOLUTION: A polystyrene expansion molded product is obtained by: dispersing polystyrene resin particles having 5-15% of a coefficient of variation (CV value) of the particle diameter of the polystyrene resin particles; supplying a flame-retardant solution obtained by dissolving 33-1,000 pts.wt. of a tetrabromocyclooctane, which is a powdery flame retardant, and 20-200 pts.wt. of a flame retardant aid, which has a 1-hour half-life temperature of 100-250°C with respect to 100 pts.wt. of a plasticizer, to the aqueous suspension before or during the infiltration of a blowing agent; prefoaming using the expandable polystyrene resin particles, wherein the flame retardant and flame retardant aid are impregnated in the polystyrene resin particles; and filling and foaming the prefoamed particles into a mold. Further, its mean bowstring length is 30-380 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an expandable polystyrene-based resin particle for heat insulating material that is excellent in foaming properties and used for a roof base material, and further, for example, heat insulation for a roof base material laid between a base material such as a field board and a roofing material. It relates to materials.

Conventionally, as a base material for roofs, in addition to waterproofing, moisture absorption, moisture proofing and heat insulation, etc., it does not cause thermal degradation under repeated high temperatures due to direct sunlight (heat resistance), nails In addition, it is required that water does not leak from the holes where the staples are struck, and that they do not expand or contract due to temperature changes (dimensional stability).
The heat insulating material used for the roof base material is the work on the roof plate in addition to the required strength because the worker can walk on it during the construction process, From the viewpoints of work safety and simplicity, it is desired to be as light as possible, and a styrene resin foam molded body having a thickness of about 10 to 200 mm is often used as a heat insulating material.

JP-A-4-351646 JP 2007-191518 A

  In the case of the roof structure, the roofing material that has been exposed to direct sunlight in the summer may become as high as about 80 ° C., and the polystyrene foam molded body arranged as a heat insulating material may also rise to about 80 ° C. In general styrenic resin foam moldings, the dimensional change rate when left in a high temperature environment of about 80 ° C. for a long time may be about −1.5% or more. Thus, there is a possibility that a gap occurs in the joined portion, and a gap may be formed between the joined end surfaces of the foamed resin molded bodies forming the heat insulating layer. When a gap is formed, rainwater enters from there and a rainwater retention area is formed between the foamed resin molded body forming the heat insulation layer and the waterproof layer as described above, thereby inducing destruction of the heat insulation material. It becomes a cause. On the other hand, in place of an organic compound such as butane and pentane, expandable styrene resin particles using carbon dioxide gas as a foaming agent have been proposed (Patent Document 1). Molded products in which pre-expanded particles obtained by heating this product are foamed in the mold, since carbon dioxide is used as the foaming agent, the amount of residual gas is small, and when left in a high temperature environment of around 80 ° C for a long time However, the dimensional change rate can be suppressed to about -0.8%. However, at a dimensional change rate of -0.8%, it is not possible to completely avoid the intrusion of rainwater due to the shrinkage of the heat insulating material and the resulting destruction of the heat insulating material.

  Patent Document 2 describes a suspension polymerization method as a method for producing expanded polystyrene resin particles, but the method for producing expanded polystyrene resin particles by suspension polymerization is the particle size of the obtained expandable polystyrene resin particles. Due to the wide distribution, there is a problem in that the pre-foamed grains are poorly filled into the mold details when molding and the moldability is poor.

  According to the present invention, after dispersing polystyrene resin particles having a coefficient of variation (CV value) of polystyrene resin particle diameter of 5 to 15% in an aqueous suspension, before or during impregnation with a foaming agent. In addition, a flame retardant tetrabromocyclooctane of 33 to 1000 parts by weight with respect to 100 parts by weight of the plasticizer, and a flame retardant having a one-hour half-life temperature of 100 ° C. to 250 ° C. with respect to 100 parts by weight of the plasticizer A base material for a roof in which a flame retardant solution obtained by dissolving 20 to 200 parts by weight of an auxiliary agent is supplied into the aqueous suspension, and the polystyrene resin particles are impregnated with the flame retardant and the flame retardant auxiliary agent. It is the expandable polystyrene resin particle for heat insulating materials used for. And it is a foaming molding obtained by filling the foam | expanded pre-expanded particle formed by pre-expanding an expandable polystyrene-type resin particle in a type | mold, Comprising: An average chord length is 30-380 micrometers.

In particular, the heat insulating roof structure according to the present invention, that is, the heat insulating material for the base material for roofing, is a polystyrene-based foamed molding that is installed between a base material such as a base plate and a roofing material, and is 168 hours at 90 ° C. When heated, it is a polystyrene-based foamed molded article having a dimensional change rate within ± 0.5% before and after the heating. The heat insulating material for the base material for the roof is a polystyrene-based foamed molded article having a density of the molded article of 0.018 to 0.033 g / cm ² , and the average chord length of the foamed body is 30 μm to 380 μm. It is characterized by. Furthermore, the heat insulating material for the base material for the roof having the dimensional change rate in the above range, that is, the polystyrene-based foam molded article is an expandable polystyrene-based resin particle having an average particle diameter of 0.3 mm to 1.2 mm, and polystyrene. It is characterized in that a foamed polystyrene resin particle having a coefficient of variation (CV value) of the resin particle diameter of 5 to 15% is pre-foamed and molded.

The roofing material that has been exposed to direct sunlight in the summer may have a high temperature of about 80 ° C., and the polystyrene foam molded body of the present invention installed as a heat insulating material may also rise to about 80 ° C. However, since the polystyrene-based foamed molding of the present invention has a dimensional change rate within ± 0.5% when heated at 90 ° C. for 168 hours, it can be dissolved, deformed, warped or expanded even at high temperatures in summer. Is excellent in temperature stability and can be used without causing thermal deterioration over a long period of time even when subjected to repeated high temperatures.
For this reason, it is possible to suppress that the heat insulating material used as a subject in a normal heat insulation roof structure destroys.
Furthermore, because it is a foamed molded product with excellent heat insulation properties by controlling the average cell diameter of the molded product, it has the effect of improving the heat insulation and airtightness inside the building. As a result, the air conditioning effect in the living space is effective. Can be maintained.
The polystyrene-based foamed molded article has an average particle diameter of 0.3 mm to 1.2 mm, and a polystyrene-based resin particle diameter variation coefficient (CV value) of 5 to 15%, which is a foamable polystyrene resin having a sharp particle size. Since the particles are pre-foamed and molded, the fluidity of the particles is very good, the filling of the pre-foamed particles into the cavities during molding is good, and the molded products with complicated shapes with curved surfaces, irregularities and grooves It is possible to mold.

  Examples of the expandable polystyrene resin particles used in the base material for roof according to the present invention include the following, but are not limited thereto.

  After dispersing polystyrene resin particles having a coefficient of variation (CV value) of polystyrene resin particle diameter of 5 to 15% in an aqueous suspension, before or during impregnation with a foaming agent, 100 weights of plasticizer 33 to 1000 parts by weight of a powder flame retardant is dissolved in part, and 20 to 200 parts by weight of a flame retardant aid having a one-hour half-life temperature of 100 ° C. to 250 ° C. per 100 parts by weight of the plasticizer is dissolved in the plasticizer. The flame retardant solution is supplied into the aqueous suspension, and the polystyrene resin particles are impregnated with the flame retardant and the flame retardant aid, and are expandable polystyrene resin particles, the flame retardant Contains 98.5 to 99.7 parts by weight of tetrabromocyclooctane and 0.3 to 1.5 parts by weight of silica fine powder.

  Here, when the flame retardant tetrabromocyclooctane was added in the form of powder, there was a problem that an aggregate of the flame retardant was generated at the bottom of the reactor during the production process.

As the polystyrene resin particles in the present invention, those produced by a known method can be used. For example, (1) an aqueous medium, a styrene monomer and a polymerization initiator are supplied into the autoclave, Suspension polymerization method for producing polystyrene resin particles by suspension polymerization of styrene monomer with heating and stirring, (2) Supplying aqueous medium and polystyrene resin seed particles into autoclave, polystyrene resin seeds After dispersing the particles in an aqueous medium, the styrene monomer is continuously or intermittently supplied while heating and stirring in the autoclave so that the polystyrene resin seed particles absorb the styrene monomer. Examples thereof include a seed polymerization method in which polystyrene resin particles are produced by polymerization in the presence of a polymerization initiator. The polystyrene-based resin seed particles may be produced and classified by the suspension polymerization method of (1) above.
Here, as the polystyrene resin in the present invention, for example, a homopolymer of a styrene monomer such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene, or the like These copolymers are mentioned.

  Further, the polystyrene-based resin is a copolymer of the styrene-based monomer having the styrene-based monomer as a main component and a vinyl monomer copolymerizable with the styrene-based monomer. Such vinyl monomers may include, for example, alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cetyl (meth) acrylate, (meth ) In addition to acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, and ethyl fumarate, difunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate are exemplified.

  The average particle diameter of the polystyrene-based resin particles is within the cavity of the pre-expanded particles obtained by pre-expanding the expandable polystyrene-based resin particles when in-mold foam molding is performed using the expandable polystyrene-based resin particles. From the viewpoint of the filling property, 0.3 to 2.0 mm is preferable, and 0.3 to 1.4 mm is more preferable. Furthermore, in the case of the heat insulating material used for the base material for roofs, 0.3-1.2 mm is preferable. If the average particle diameter of the particles exceeds 2.0 mm, the filling property of the pre-foamed particles in the cavity deteriorates, so that the filling failure occurs and the foam particles cannot be filled in the details of the mold, so that a foamable body cannot be obtained. There was a problem. On the other hand, when the average particle diameter of the particles is less than 0.3 mm, the strength of the molded body is insufficient, and there is a problem that the molded body breaks during construction.

  The coefficient of variation (CV value) of the polystyrene resin particle diameter of the present invention is preferably 5 to 15%, more preferably 5.5 to 12%. Furthermore, 6 to 9% is preferable. When the CV value exceeds 20%, the filling property of the polystyrene-based resin particles into the cavity of the pre-foamed body deteriorates, and the foam particles cannot be filled into the details of the mold. It was. On the other hand, if the CV value is less than 3%, many steps are required at the time of production, and the production cost increases, which is not preferable.

  Furthermore, if the polystyrene-based weight average molecular weight of the polystyrene-based resin constituting the polystyrene-based resin particles is small, the mechanical strength of the polystyrene-based resin foam molded article obtained by foaming the expandable polystyrene-based resin particles may decrease. On the other hand, if it is large, the foamability of the expandable polystyrene resin particles is lowered, and there is a possibility that a polystyrene resin foam molded article having a high expansion ratio cannot be obtained. ~ 400,000 is more preferable.

The polymerization initiator used in the suspension polymerization method and the seed polymerization method is not particularly limited. For example, benzoyl peroxide, lauryl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxide, t -Butyl peroxypivalate, t-butyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexyl monocarbonate, isopropyl carbonate, t-butyl peroxyacetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxy-3,3,5 trimethylhexanoate, di-t-butylperoxyhexahydroterephthalate, 2,5-dimethyl-2,5 -Bis (benzoylperoxy) hex And organic peroxides such as dicumyl peroxide and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. These may be used alone or in combination of two or more. Good.
The aqueous suspension in which polystyrene resin particles are dispersed in an aqueous medium may be obtained by using the reaction liquid after polymerization by the suspension polymerization method or the seed polymerization method as an aqueous suspension, or the suspension described above. The polystyrene resin particles obtained by the turbid polymerization method or the seed polymerization method may be separated from the reaction solution, and the polystyrene resin particles may be suspended in a separately prepared aqueous medium to form an aqueous suspension. In addition, it does not specifically limit as an aqueous medium, For example, water, alcohol, etc. are mentioned, Water is preferable.

  In the suspension polymerization method or seed polymerization method, a suspension stabilizer is used to stabilize the dispersibility of the styrene monomer droplets or polystyrene resin seed particles when the styrene monomer is polymerized. Examples of such a suspension stabilizer include water-soluble polymers such as polyvinyl alcohol, methylcellulose, polyacrylamide, and polyvinylpyrrolidone, and poorly water-soluble inorganic salts such as calcium triphosphate and magnesium pyrophosphate. In the case of using a poorly water-soluble inorganic salt, an anionic surfactant is usually used in combination.

  Examples of the anionic surfactant include alkyl sulfates such as sodium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, higher fatty acid salts such as sodium oleate, and β-tetrahydroxynaphthalene sulfonate. And alkylbenzene sulfonates are preferred.

  And in the manufacturing method of the expandable polystyrene resin particle of this invention, a foaming agent is impregnated in the well-known manner in the polystyrene resin particle disperse | distributed in the said aqueous suspension. As such a foaming agent, a boiling point is not higher than the softening point of the polystyrene-based resin, and a gaseous or liquid organic compound at normal pressure is suitable. For example, propane, n-butane, isobutane, n-pentane, Hydrocarbons such as isopentane, neopentane, cyclopentane, cyclopentadiene, n-hexane, petroleum ether, ketones such as acetone and methyl ethyl ketone, alcohols such as methanol, ethanol, isopropyl alcohol, dimethyl ether, diethyl ether, dipropyl ether, methyl Examples thereof include low boiling point ether compounds such as ethyl ether, inorganic gases such as carbon dioxide, nitrogen and ammonia, and hydrocarbons having a boiling point of −45 to 40 ° C. are preferred, propane, n-butane, isobutane, n-pentane, Isopentane is more preferred Arbitrariness. In addition, a foaming agent may be used independently or 2 or more types may be used together.

  The expandable polystyrene resin particles of the present invention are obtained by adding a powder flame retardant tetrabromocyclooctane, a flame retardant to a plasticizer before or during impregnation with a polystyrene resin particle dispersed in an aqueous suspension. A flame retardant solution obtained by dissolving the auxiliary agent is supplied into the aqueous suspension, and the polystyrene resin particles are impregnated with the flame retardant and the flame retardant auxiliary agent. The impregnation is preferably performed under pressure. The aqueous medium is not particularly limited as long as it is compatible with the aqueous suspension in which the polystyrene resin particles are dispersed. Examples thereof include water and alcohol, and water is preferable.

The powdery flame retardant tetrabromocyclooctane is added with fine silica powder in order to improve dispersibility. That is, the powdery flame retardant is desirably tetrabromocyclooctane predispersed with fine silica powder. As a method for adding the fine silica powder to tetrabromocyclooctane, it is preferable to mix for a certain time in a mixer such as a Henschel mixer.
As the fine silica powder to be added to the powder flame retardant tetrabromo cyclooctane, specific surface area of 170~330m ² / g in the case if may be either hydrophilic or hydrophobic, and a specific surface area of 200 meters ² / g is Most preferred. When the specific surface area was less than 170 m ² / g, the dispersibility of tetrabromocyclooctane could not be improved, resulting in secondary aggregation of tetrabromocyclooctane. On the other hand, when the specific surface area is larger than 330 m ² / g, there is a problem that the amount of silica fine powder scattered increases and the handling property in production deteriorates.
The amount of silica fine powder added to tetrabromocyclooctane is preferably 0.3 to 1.5 parts by weight of silica fine powder relative to 98.5 to 99.7 parts by weight of tetrabromocyclooctane, Is most preferably 0.5 parts by weight. If it is less than 0.3 part by weight, the dispersibility of tetrabromocyclooctane could not be improved, and as a result, tetrabromocyclooctane secondary aggregated. On the other hand, when the amount is more than 1.5 parts by weight, there is a problem that the amount of silica fine powder scattered increases and the handling property in production deteriorates.

  Furthermore, by using a flame retardant aid in combination with the above flame retardant, it is possible to impart further excellent flame retardancy to the expandable resin particles. Such a flame retardant aid is not particularly limited, and examples thereof include dicumyl peroxide, and those having a one-hour half-life temperature of 100 ° C. to 250 ° C. are preferable. And, if the content of the flame retardant aid in the expandable resin particles is small, the flame retardancy of the expandable resin particles may decrease, but at most, it changes to the flame retardancy of the expandable resin particles. 20 to 200 parts by weight with respect to 100 parts by weight of the plasticizer, that is, 0.2 to 2.0 parts by weight with respect to 100 parts by weight of the expandable polystyrene resin is preferable. More preferably, 5 parts by weight.

The flame retardant solution is prepared by dissolving a powdery flame retardant and a flame retardant aid in a plasticizer. Such a plasticizer is not particularly limited as long as it can dissolve the flame retardant. For example, diisobutyl adipate, diisononyl adipate, dioctyl phthalate, dibutyl phthalate, Examples of sebacic acid esters include dibutyl sebacate, and examples of hydrocarbons include styrene, toluene, ethylbenzene, and cyclohexane, with styrene and toluene being particularly preferred.
And the content of the powdered flame retardant in the flame retardant solution increases the amount of the flame retardant solution that must be used if it is small, while the impregnation of the flame retardant into the polystyrene resin particles decreases, If the amount is too large, the flame retardant becomes difficult to dissolve in the plasticizer, so the amount is limited to 33 to 1000 parts by weight and preferably 100 to 550 parts by weight with respect to 100 parts by weight of the plasticizer.
Furthermore, when supplying the flame retardant solution in the aqueous suspension, the content of the flame retardant in the obtained expandable polystyrene resin particles is 100 parts by weight of the polystyrene resin particles impregnated with the flame retardant. It is preferable to adjust so that it may preferably become 0.3-2.0 weight part, More preferably, it may become 0.5-1.5 weight part. This is because when the content of the flame retardant in the expandable polystyrene resin particles is small, the self-extinguishing property of the obtained thermoplastic polystyrene resin foam molded article may be deteriorated.
Since the powdery flame retardant tetrabromocyclooctane contained in the plasticizer is stably dispersed by the fine silica powder, it is uniformly dispersed in the plasticizer. Further, since the plasticizer is liquid and is uniformly and stably dispersed in the aqueous suspension, the powdered flame retardant dispersed uniformly in the plasticizer is also uniformly dispersed in the aqueous suspension. It is possible to stably disperse, and thus it is possible to impregnate the flame retardant uniformly and with excellent impregnation efficiency in each polystyrene resin particle dispersed in the aqueous suspension.
The procedure for dissolving the powdered flame retardant and the flame retardant aid in the plasticizer is not particularly limited. For example, after the plasticizer is heated to a predetermined temperature, the plasticizer is stirred and powdered in the plasticizer. Examples include a method of adding a flame retardant.
The aqueous medium is not particularly limited as long as it is compatible with the aqueous suspension in which the polystyrene resin particles are dispersed, and examples thereof include water, alcohol, and the like. The same aqueous medium as the aqueous suspension to be dispersed is preferable.
If the amount of the aqueous medium in which the flame retardant solution is dispersed is small, the flame retardant solution may not be stably dispersed in the aqueous medium. Since the impregnation efficiency of the flame retardant may be lowered, the amount is limited to 100 to 3000 parts by weight and preferably 200 to 2000 parts by weight with respect to 100 parts by weight of the plasticizer in the flame retardant solution.

In addition, when the flame retardant solution is dispersed in an aqueous medium, the interfacial energy between the flame retardant solution and the aqueous medium is reduced in the aqueous medium to make the flame retardant solution more stable in the flame retardant solution. A surfactant may be contained in order to be dispersed.
Examples of such surfactants include, but are not limited to, alkyl sulfates such as sodium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, higher fatty acid salts such as sodium oleate, β-tetrahydroxy Anionic surfactants such as naphthalene sulfonates; alkyl ammonium acetates, alkyl dimethyl benzyl ammonium salts, alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, alkyl pyridinium salts, oxyalkylene alkyl amines, polyoxyalkylene alkyl amines, etc. Cationic surfactants; fatty acid diethanolamides, silicone surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl alkyls Vinyl ether, and polyoxyethylene-polyoxypropylene glycol, include such nonionic surfactants such as polyether-modified silicones, preferably anionic surfactants, alkylbenzenesulfonate is preferable. In addition, surfactant may be used independently or 2 or more types may be used together.
When the amount of the surfactant used is small, the dispersibility of the flame retardant solution in the aqueous medium is not improved. On the other hand, when the amount is large, foaming due to the surfactant becomes excessive, causing production trouble. Therefore, the amount is preferably 0.005 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the plasticizer in the flame retardant solution.

Further, when the flame retardant solution is dispersed in an aqueous medium, it is preferable to contain a hardly water-soluble inorganic salt in the aqueous medium. Examples of such a hardly water-soluble inorganic salt include tricalcium phosphate, hydroxyapatite, and the like. , Magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, magnesium phosphate, magnesium carbonate and the like, and magnesium pyrophosphate is preferred.
If the amount of the hardly water-soluble inorganic salt used is small, the dispersibility of the flame retardant solution in an aqueous medium may be reduced. On the other hand, if the amount is large, the viscosity of the dispersion obtained by dispersing the flame retardant solution may be reduced. And the flame retardant solution cannot be uniformly dispersed in the aqueous medium. Therefore, the amount is preferably 10 to 500 parts by weight, more preferably 20 to 200 parts per 100 parts by weight of the plasticizer in the flame retardant solution. Part by weight is preferred.
As a procedure for dispersing the flame retardant solution in the aqueous medium, the plasticizer may be dispersed in the aqueous medium in a state in which the powdered flame retardant and the flame retardant aid are all dissolved in the plasticizer. A surfactant or a hardly water-soluble inorganic salt is added to the aqueous medium as necessary and heated to a predetermined temperature, and then a powdered flame retardant, a flame retardant aid and a plasticizer are added and stirred to form a powder. A method of dissolving a flame retardant in a plasticizer to form a flame retardant solution and simultaneously dispersing the flame retardant solution in an aqueous medium, and adding a surfactant or a hardly water-soluble inorganic salt to the aqueous medium as needed Then, while heating to a predetermined temperature, a powdered flame retardant is dissolved in a plasticizer to prepare a flame retardant solution, and this flame retardant solution is fed into the aqueous medium and dispersed by stirring. Can be mentioned.

The flame retardant solution or a dispersion of the flame retardant solution obtained by dispersing the flame retardant solution in an aqueous medium is added to the aqueous suspension in which the polystyrene resin particles are dispersed. The flame retardant solution or the dispersion of the flame retardant solution may be added to the aqueous suspension of the flame retardant solution or the flame retardant solution. The total amount of the dispersion may be added all at once, the flame retardant solution or the dispersion of the flame retardant solution may be added in several portions, or the flame retardant solution or the flame retardant You may add the dispersion of a solution continuously little by little.
Then, after the polystyrene resin particles dispersed in the aqueous suspension are impregnated with a foaming agent, a flame retardant, and a flame retardant aid, the expandable polystyrene resin particles are manufactured, and then the expandable polystyrene resin particles are used. The aqueous suspension may be taken out, and the expandable polystyrene resin particles may be washed and dried as necessary.

  In addition to the flame retardant, the foamable polystyrene resin particles may be added with additives such as a bubble adjusting agent, a filler, a lubricant, a colorant, and a solvent as needed within a range that does not impair the physical properties. When these additives are added to the expandable polystyrene resin particles, the additives are added to the aqueous suspension in which the polystyrene resin particles are dispersed, or the flame retardant solution or the flame retardant is added. An additive may be added to the dispersion of the solution.

Next, the manufacturing point of a polystyrene-type resin foam molding using the said expandable polystyrene-type resin particle is demonstrated. As a procedure for producing a polystyrene resin foam molded article using the expandable polystyrene resin particles, a known method can be employed. Specifically, the expandable polystyrene resin particles are heated and pre-expanded. The polystyrene resin pre-expanded particles having a bulk density of about 0.01 to 0.05 g / cm ³ are filled into the mold cavity, heated, and foamed to form a polystyrene resin. A foamed molded product can be obtained.

  The average chord length of the foam is preferably 30 to 380 μm, more preferably 40 to 350 μm. Furthermore, when used for the heat insulating material of the base material for roofs, 50 micrometers-330 micrometers are preferable. This is because when the average chord length of bubbles in the foamed molded product is small, the number of the bubble walls in the foamed molded product, that is, the surface area of the cell walls increases too much, and the thickness of each cell wall becomes thin. Although the number increases and the number of times of heat blocking increases, the degree of decrease in the heat blocking effect by the cell walls increases, and as a result, shrinkage of the foamed molded body increases. On the other hand, when the average chord length of the foamed molded product is large, the total number of bubbles in the thickness direction of the foamed molded product decreases, and as a result, the strength of the foamed molded product decreases.

  On the other hand, if the density of the above-mentioned hot polystyrene resin foam molded article is low, the closed cell ratio of the polystyrene resin foam molded article may be lowered, and the heat insulation and mechanical strength of the polystyrene resin foam molded article may be lowered. If it is high, the time required for one cycle in the in-mold foam molding becomes long, and the production efficiency of the polystyrene-based resin foam molded article may be lowered, so 0.01 to 0.05 g / cm 3 is preferable. Furthermore, 0.018 to 0.033 g / cm <3> is preferable when used for a roof base material.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

Example 1
In an autoclave with a stirrer having an internal volume of 100 liters, 120 g of tribasic calcium phosphate (manufactured by Ohira Chemical Co., Ltd.), 2.4 g of sodium dodecylbenzenesulfonate, 160 g of benzoyl peroxide (purity 75% by weight), t-butylperoxy-2-ethylhexyl 30 g of monocarbonate, 40 kg of ion-exchanged water and 40 kg of styrene monomer were supplied, and the stirring blade was rotated at a rotational speed of 100 rpm and stirred to form an aqueous suspension.
Next, while stirring the aqueous suspension by rotating the stirring blade at a rotation speed of 100 rpm, the temperature in the autoclave is raised to 90 ° C. and held at 90 ° C. for 6 hours. The temperature inside was raised to 120 ° C. and maintained at 120 ° C. for 2 hours, whereby the styrene monomer was subjected to suspension polymerization.
Thereafter, the temperature in the autoclave is cooled to 25 ° C., the polystyrene particles are taken out from the autoclave, washed and dehydrated repeatedly, and after passing through a drying step, the polystyrene particles are classified, and the particle size is reduced. Polystyrene particles having 0.2 to 0.8 mm and a weight average molecular weight of 240,000 were obtained.

Next, 35 kg of ion-exchanged water, 4 g of sodium dodecylbenzenesulfonate, and 200 g of magnesium pyrophosphate were supplied to another 100 liter autoclave with a stirrer, and then 8000 g of the polystyrene particles were supplied as seed particles into the autoclave and stirred. Dispersed uniformly in water.
Separately from the above, a dispersant is prepared by dissolving 3 g of sodium dodecylbenzenesulfonate in 5 kg of ion-exchanged water, while the polymerization initiator is added to 1994 g of styrene, 500 g of α-methylstyrene and 6 g of divinylbenzene. -Styrene monomer by dissolving 100 g of dimethyl-2,5-di (benzoylperoxy) hexane (10-hour half-life temperature: 100 ° C.) and 100 g of dicumyl peroxide (10-hour half-life temperature: 116 ° C.) A solution was prepared, and this styrenic monomer solution was added to the dispersion and stirred using a homomixer to make an emulsion, thereby obtaining an emulsion.
Then, after heating and maintaining the autoclave at 80 ° C., the above emulsion is added to the autoclave so that styrene, α-methylstyrene, divinylbenzene and a polymerization initiator are smoothly absorbed in the polystyrene seed particles. The autoclave was heated from 80 ° C. to 118 ° C. at a rate of 1 ° C./min. When the temperature reached 118 ° C., 22,000 g of styrene and 7500 g of α-methylstyrene were continuously dropped into the autoclave over 480 minutes, and then 60 ° C. after completion of dropping of the styrene monomer, The temperature was raised to 140 ° C. at a temperature raising rate of 1 minute and held for 120 minutes to obtain polystyrene particles by seed polymerization. Styrene, α-methylstyrene and divinylbenzene were all used for the polymerization.

Further, 2.24 g of silica (trade name “AEROSIL200” manufactured by Nippon Aerosil Co., Ltd.) as a fluidizing agent is added to 440 g of the flame retardant tetrabromocyclooctane (trade name “Pyroguard FR-200” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and dry-mixed. A flame retardant A was prepared (for example, Henschel mixer).
Further, 6 g of sodium dodecylbenzenesulfonate and 112 g of magnesium pyrophosphate obtained by the metathesis method were supplied to 2 kg of ion-exchanged water, stirred and heated and maintained at 50 ° C., while 240 g of toluene as a plasticizer was added to the ion-exchanged water. In addition, 440 g of flame retardant A and 140 g of flame retardant auxiliary dicumyl peroxide were added, and the mixture was stirred for 30 minutes at 7000 rpm using a homomixer (TK homomixer MARKII fmodel manufactured by Tokushu Kika Kogyo Co., Ltd.). A and a flame retardant assistant were all dissolved therein to form a flame retardant solution, and at the same time, this flame retardant solution was dispersed in ion-exchanged water to form a flame retardant solution dispersion.
Next, after the inside of the autoclave was cooled to 50 ° C. at a temperature lowering rate of 1 ° C./min, the flame retardant solution was supplied into the autoclave.
The autoclave was sealed 30 minutes after supplying the flame retardant solution in the autoclave, and then 3600 g of butane (isobutane / normal butane (weight ratio) = 30/70) and pentane (isopentane / Normal pentane (weight ratio) = 20/80) 1600 g was pressed into the autoclave for 30 minutes by nitrogen pressurization, and the temperature inside the autoclave was raised to the temperature shown in “Foaming agent impregnation temperature” in Table 1 at that temperature. Hold for 4 hours.
Thereafter, the inside of the autoclave is cooled to 25 ° C., the expandable polystyrene particles are taken out from the autoclave, washed and dehydrated repeatedly, and after passing through a drying step, the flame retardant expandable polystyrene particles are classified. Thus, thermoplastic foamable polystyrene particles having a particle diameter of 0.80 to 1.2 mm and an average particle diameter of 1.0 mm were obtained. All flame retardant solution was impregnated with polystyrene particles.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Example 2)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant A was changed to 360 g instead of 440 g.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Example 3)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant A was changed to 679 g instead of 440 g.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

Example 4
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the blowing agent impregnation temperature was 93 ° C. instead of 95 ° C.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Example 5)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the foaming agent impregnation temperature was 98 ° C instead of 95 ° C.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Example 6)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that expandable polystyrene resin particles having a CV value of 9.31% were used.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Example 7)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that expandable polystyrene resin particles having a CV value of 6.09% were used.
When the foamed molded article obtained by filling the foamed pre-expanded particles, which were pre-expanded using the expandable polystyrene particles, into a mold was prepared, the filling property into the cavity was good. Further, the obtained foamed molded article had no unevenness in the fused part between the foamed particles, and the flame retardant was uniformly absorbed. Further, when the average chord length of the obtained foamed molded article was measured, the amount of the flame retardant used was moderate, and thus no bubble densification was observed. Further, the obtained foamed molded article has excellent heat insulation performance, and when heated at 90 ° C. for 168 hours, the heating dimensional change before and after the heating is within ± 0.5%, and is heat resistant. Was excellent.

(Comparative Example 1)
When expandable polystyrene resin particles having a CV value of 20.80% were used, the filling property of the pre-expanded particles in the cavity during molding was poor, and a foamed molded article could not be obtained.

(Comparative Example 2)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant A was changed to 80 g instead of 440 g. For this reason, non-uniform absorption of the flame retardant occurred, and irregularities were observed in the fused part between the foamed particles of the foamable molded article.

(Comparative Example 3)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant A was changed to 1200 g instead of 440 g. When the average chord length of the obtained foamed molded product was measured, the amount of the flame retardant used was large, and the cells were denser. Therefore, unevenness was observed in the fused part between the foamed particles of the foamable molded article.

(Comparative Example 4)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the blowing agent impregnation temperature was 80 ° C. instead of 100 ° C. When the average chord length of the obtained foamed molded product was measured, it was 480 μm and the heat insulation performance was poor.

(Comparative Example 5)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the blowing agent impregnation temperature was 110 ° C. instead of 100 ° C. When the average chord length of the obtained foamed molded product was measured, it was 25 μm and the heat insulation performance was poor.

(Measurement method of average particle size)
About 50 to 100 g of a sample was screened using a low-tap type sieve shaker (manufactured by Iida Seisakusho Co., Ltd.) with a sieve opening of 4.00 mm, an opening of 3.35 mm, an opening of 2.80 mm, an opening of 2.36 mm, Aperture 2.00 mm, Aperture 1.70 mm, Aperture 1.40 mm, Aperture 1.18 mm, Aperture 1.00 mm, Aperture 0.85 mm, Aperture 0.71 mm, Aperture 0.60 mm, Aperture 0 .Classified with a JIS standard sieve of 50 mm, aperture 0.425 mm, aperture 0.355 mm, aperture 0.300 mm, aperture 0.250 mm, aperture 0.212 mm, aperture 0.180 mm for 10 minutes. The particle diameter (median diameter) at which the cumulative weight is 50% based on the cumulative weight distribution curve obtained by measuring the above sample weight is referred to as the average particle diameter.
(Measurement method of coefficient of variation (CV value) of polystyrene resin particle diameter)
The variation coefficient (CV value) of the polystyrene resin particle diameter is a value calculated by substituting the standard deviation (δ) of the particle diameter and the average particle diameter (x) into the following formula.
CV value (%) = (δ / x) × 100

(Method for measuring the specific surface area of silica)
All methods for measuring the specific surface area of the silica fine powder used in the present invention are based on the BET method.

(Blocking evaluation of flame retardant A)
100 g of flame retardant was put in a polyethylene bag, packed in a 50 mm diameter cylinder, loaded with a 1.1 kg weight and stored in an oven at 40 ° C. for 1 month, then taken out and observed for evaluation.
× ・ ・ ・ The flame retardant is solid in a very hard state, and does not collapse even when gripped.
Δ: Although the flame retardant is hardened in a hard state, it collapses when held by hand.
○: There is a tightness but no solidity, and it is in a smooth state.
The obtained expandable polystyrene particles were measured for pre-expandability, foam moldability, combustibility, and the average chord length of bubbles in the foam molded product in the following manner. The results are shown in Table 1.

(Pre-foaming property)
40000 g of the obtained expandable polystyrene particles, 20 g of polyethylene glycol as a surface treating agent, 60 g of zinc stearate, 12 g of hydroxyglyceride stearate (trade name “K-3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.) and stearic acid 20 g of monoglyceride (trade name “Riquemar S-100P” manufactured by Riken Vitamin Co., Ltd.) was supplied to a tumbler mixer and stirred for 30 minutes to coat the surface treatment agent on the surface of the expandable polystyrene particles.
Next, after the expandable polystyrene particles are stored in a 15 ° C. cool box for 48 hours, 500 g of expandable polystyrene particles are supplied to a pre-foaming machine equipped with a stirrer and heated using water vapor to be pre-expanded. Thus, pre-expanded particles having a bulk ratio of 50 times were obtained.

(Foam moldability)
The polystyrene pre-expanded particles are filled into a mold of a foam molding machine (trade name “ACE-3SP” manufactured by Sekisui Koki Co., Ltd.) and subjected to secondary foaming using water vapor, so that the length is 300 mm × width 400 mm × height. A 30 mm rectangular solid foam molded product was obtained.

(Appearance evaluation of foam molding)
The appearance of the foamed molded product was visually observed and evaluated based on the following criteria.
○: The fused part between the expanded particles was smooth.
X: Concavities and convexities were generated in the fused part between the expanded particles.

(Flammability test)
Five test pieces having a rectangular parallelepiped shape having a length of 200 mm, a width of 25 mm, and a height of 10 mm were cut out from the obtained polystyrene foam molded article with a vertical cutter, and after curing in a 60 ° C. oven for 1 day, the measurement method A of JIS A9511-2006 was applied. Measurements were carried out in accordance with the above, and the average value of five test pieces was obtained and used as the flame extinction time, and comprehensively evaluated based on the following criteria. The results are shown in Tables 1 and 2 as self-extinguishing properties. In the JIS standard, the flame extinguishing time needs to be within 3 seconds, preferably within 2 seconds, and more preferably within 1 second.
X: The flame extinguishing time exceeds 3 seconds, or even one of the test pieces has residue or burns beyond the flammability limit indicating line.
○: The flame extinguishing time is within 3 seconds, and all five samples have no residue and do not burn beyond the combustion limit indicator line.
◎ ・ ・ ・ Extinguishing time is less than 1 second, and all five samples have no residue and do not burn beyond the combustion limit indicator line.

(Average string length)
The average chord length of the foam molded article refers to that measured in accordance with the test method of ASTM D2842-69. Specifically, the foamed molded body is cut into approximately equal halves, and the cut surface is photographed at a magnification of 100 times using a scanning electron microscope (trade name “S-3000N” manufactured by Hitachi, Ltd.). To do. The photographed image is printed on A4 paper, and a straight line with a length of 60 mm is drawn at an arbitrary position. From the number of bubbles existing on this straight line, the average chord length (t) of the bubbles is calculated by the following equation.
Average string length t = 60 / (number of bubbles × photo magnification)
When drawing a straight line, if the straight line would make point contact with the bubble as much as possible, this bubble was included in the number of bubbles, and both ends of the straight line were positioned within the bubble without penetrating the bubble. In the case of the state, the bubble in which both ends of the straight line are located is included in the bubble number. Further, the average chord length is calculated in the same manner as described above at any five locations in the photographed image, and the arithmetic mean value of these average chord lengths is taken as the average chord length of the foam molded article.

(Thermal conductivity)
A rectangular parallelepiped test piece having a length of 200 mm, a width of 200 mm, and a height of 10 to 25 mm was cut out from the foam molded article.
Using a measuring device commercially available from EKO SEIKI under the trade name “HC-074 / 200”, the low sound plate of the measuring device is 15 ° C. lower than the average temperature of the test piece and the high temperature plate is lower than the average temperature of the test piece. Is set 15 ° C. higher, and the thermal conductivity of the test piece is JIS A 1412-2: 1999 “Method of measuring thermal resistance and thermal conductivity of thermal insulation material—Part 2: Heat flow meter method (HFM method)” The measurement was performed according to the described method. In addition, the average temperature of the test piece was 3 points | pieces, 0, 20, and 30 degreeC. Based on the obtained thermal conductivity, a regression line was drawn with the horizontal axis representing temperature and the vertical axis representing thermal conductivity, and the thermal conductivity of the test piece at 23 ° C. was calculated.
The thermal conductivity of an extruded polystyrene standard plate (NIST-SRM1453) from the National Institute of Standards and Technology was measured in the same manner as described above. And the correction | amendment of a measuring apparatus was performed by the following formula using the thermal conductivity and nominal value (23 degreeC calculated value) of an extrusion method polystyrene standard board, and the value after correction | amendment was made into the thermal conductivity of a test piece.
Thermal conductivity λ (W / m · K)
= Thermal conductivity at 23 ° C of test piece x Nominal value of extruded polystyrene standard plate (calculated value at 23 ° C)
/ Thermal conductivity of extruded polystyrene standard plate at 23 ° C

(Heat-resistant)
A test piece having a rectangular parallelepiped shape having a length of 120 mm, a width of 120 mm, and a height of 30 mm was cut out from the foamed molded product, and the dimensional change rate of heating after leaving the test piece at 90 ° C. for 168 hours was measured according to JIS K6767: 1999 ( Measured according to dimensional stability at high temperature: method B). In addition, the case where the heating dimensional change rate was within ± 0.5% was indicated as “◯”, and the case where the heating dimensional change rate was below −0.5% or above 0.5% was indicated as “X”.

(Br amount)
The amount of Br contained in the molded product is measured by an order analysis method (thin film method) using a fluorescent X-ray analyzer (RIX-2100 manufactured by Rigaku Corporation). That is, a polystyrene foam is hot pressed at 2 to 3 g at 200 ° C. to 230 ° C. to produce a film having a thickness of 0.1 mm to 1 mm, a length of 5 cm, and a width of 5 cm. After measuring the weight of the film, the basis weight is calculated, the balance component is C8H8, and the Br amount is calculated from the X-ray intensity by the order analysis method.

Claims (6)

  After dispersing polystyrene resin particles having a coefficient of variation (CV value) of polystyrene resin particle diameter of 5 to 15% in an aqueous suspension, before or during impregnation with a foaming agent, 100 weights of plasticizer Flame retardant auxiliary agent having a powdery flame retardant tetrabromocyclooctane of 33 to 1000 parts by weight, and further a plasticizer of 100 parts by weight with a 1 hour half-life temperature of 100 ° C. to 250 ° C. For roofs, wherein a flame retardant solution in which a part is dissolved in a plasticizer is supplied into the aqueous suspension, and the polystyrene resin particles are impregnated with the flame retardant and a flame retardant aid. Expandable polystyrene resin particles for heat insulating materials used for base materials. The powdery flame retardant tetrabromocyclooctane according to claim 1, wherein the fine silica powder contains 0.3 to 1.5 parts by weight with respect to 98.5 to 99.7 parts by weight. The expandable polystyrene resin particle for heat insulating materials used for the base material for roofs of Claim 1. The flame retardant solution is dispersed in 100 to 3000 parts by weight of an aqueous medium with respect to 100 parts by weight of the plasticizer, and 0.005 to 10 parts by weight of a surfactant is contained in the aqueous medium. The expandable polystyrene-type resin particle for heat insulating materials used for the base material for roofs of Claim 1 characterized by the above-mentioned. A pre-expanded particle for a heat insulating material used for a base material for a roof, wherein the expandable polystyrene resin particles for a heat insulating material used for the base material for a roof according to claim 1 are pre-expanded. A heat insulating material for a base material for a roof, which is a foam-molded product obtained by filling the foamed pre-expanded particles according to claim 4 into foam and having an average chord length of 30 to 380 µm. A polystyrene-based foam molded article obtained by filling the pre-expanded particles according to claim 4 into a mold and foaming,
The density of the polystyrene-based foamed molded product is 0.018 to 0.033 g / cm3,
The foamed molded article has an average chord length of 30 to 380 μm,
The polystyrene-based foam molded article is a heat insulating material for a base material for a roof, which is a polystyrene-based resin particle having an average particle diameter of 0.3 mm to 1.2 mm.