JP2011012117A - Expandable polystyrenic resin particles for heat insulating material used for automobile interior material and heat insulating material for automobile interior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the use of hexabromocyclododecane, excellent in flame retardancy and heat insulation, excellent in that it does not expand or contract due to temperature change (dimensional stability), and has a small amount of volatile organic compounds and environmental hygiene The foamed molded product obtained is excellent in environmental hygiene with a good amount of heat fusion and a small amount of volatile organic compounds.
SOLUTION A solubility parameter value (SP value) is 8.3 or more and 9.4 or less after polystyrene resin particles are dispersed in an aqueous suspension and before or during impregnation with a foaming agent. 40-300 parts by weight of 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane as a brominated flame retardant per 100 parts by weight of the plasticizer is dissolved in the plasticizer. Supplying the flame retardant solution prepared in the aqueous suspension,
Using the expandable polystyrene resin particles impregnated with the flame retardant in the polystyrene resin particles, pre-expanded,
A polystyrene-based foam molded article obtained by filling the pre-expanded particles in a mold and foaming, and has an average chord length of 40 to 150 μm.
[Selection figure] None

Description

  The present invention is excellent in environmental compatibility and flame retardancy, and further has a low content of flame retardant, which is an organic additive, and is used for automobile interior materials, particularly floor spacers, door pads, tool boxes and the like. The present invention relates to conductive polystyrene resin particles and automobile interior materials.

  Conventionally, many synthetic resins are used as interior materials in many vehicles such as automobiles. Non-foamed synthetic resin products are also used, but foaming of synthetic resin is necessary for the purpose of improving cushioning and improving ride comfort, absorbing impacts to protect passengers, and ensuring flatness in the vehicle. Car interior materials that are molded products are often used. Various resins such as expandable urethane and expandable polystyrene are used as the expandable synthetic resin, but expandable polystyrene resins are often used because of their excellent moldability and functionality. In recent years, automobile interior materials have been strongly demanded to extremely reduce the content of volatile organic substances in the vehicle. Examples of volatile organic compounds include styrene monomers, aromatic organic compounds such as toluene, ethylbenzene, and xylene, aliphatic hydrocarbons up to carbon 16 (normal pressure boiling point 287 ° C.), cyclohexane And cycloaliphatic hydrocarbons such as methylcyclohexane, and acetates such as methyl acetate and butyl acetate.

JP-A-11-106548 JP 2003-64212 A

  Any organic compound in the foamed molded product has an effect of enhancing the foaming ability and the fusing property of the expandable polystyrene resin particles. However, if these contents are reduced, foamability is deteriorated, and not only lowering of the density is difficult, but also the fusion property of the molded product is deteriorated, and there is a problem that mechanical strength is also lowered. In addition, expandable polystyrene resin particles used for automobile members are also required to have a certain standard of flame retardancy, and Patent Document 2 discloses a suspension polymerization method as a specific method for producing expandable polystyrene resin particles. Are listed. However, it is desired to eliminate the use of hexabromocyclododecane from the viewpoint of accumulation in a living body.

In the present invention, the solubility parameter value (SP value) is 8.3 or more and 9.4 or less after the polystyrene resin particles are dispersed in the aqueous suspension and before or during the impregnation with the foaming agent. 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane 40 to 300 parts by weight as a brominated flame retardant with respect to 100 parts by weight of the plasticizer, and further SP value) Is obtained by dissolving 20 to 200 parts by weight of a flame retardant aid having a half-life temperature of 100 ° C. to 250 ° C. with respect to 100 parts by weight of a plasticizer having an A of 8.3 or more and 9.4 or less. Supply the flame retardant solution into the aqueous suspension,
It is an expandable polystyrene resin particle for a heat insulating material used for an interior material of an automobile, wherein the polystyrene resin particle is impregnated with the flame retardant and a flame retardant aid. And it is the 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 40-150 micrometers.
In particular, the automobile member according to the present invention is a polystyrene-based foam molded article used for automobile interior materials, particularly floor spacers, upper pads, tool boxes, and the density of the polystyrene-based foam molded article is 0.016 to 0.066 g / It is cm3, The average chord length of a foaming molding is 40 micrometers-150 micrometers, It is characterized by the above-mentioned.

The polystyrene foam used in the automobile interior material of the present invention uses, for example, an adipate as an organic compound having an SP value of 8.3 or more and 9.4 or less as a plasticizer. Polystyrene foam in which the total weight of one or more aromatic organic compounds selected from the group consisting of ethylbenzene, isopropylbenzene, normal propylbenzene, xylene and toluene is less than 1000 ppm relative to the total weight of the polystyrene foam It is characterized by its body.
Furthermore, the polystyrene-based foamed molded article having a dimensional change rate in the above range is characterized by using a foamed polystyrene-based resin particle having an average particle diameter of 0.6 mm to 1.2 mm and pre-foamed and molded. Yes.

The polystyrene foam used in the automobile interior material of the present invention can eliminate the use of hexabromocyclododecane, has excellent flame retardancy and thermal insulation, and does not expand or contract due to temperature changes (dimensional stability). Is excellent. In addition, since the content of easily volatile organic compounds such as formaldehyde, toluene, xylene, styrene and the like is suppressed to less than 1000 ppm, the amount of volatile organic compounds is small, and environmental hygiene is excellent.
Further, since an adipic acid ester having an SP value of 8.3 or more and 9.4 or less is used as a plasticizer for the expandable polystyrene resin particles, for example, the obtained foam molded product is an organic compound that has good thermal fusion and volatilizes. Small quantity and excellent environmental sanitation.

  Examples of the expandable polystyrene resin particles used in the automobile interior material of the present invention include, but are not limited to, the following.

In the present invention, the solubility parameter value (SP value) is 8.3 or more and 9.4 or less after the polystyrene resin particles are dispersed in the aqueous suspension and before or during the impregnation with the foaming agent. 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane 40 to 300 parts by weight as a brominated flame retardant with respect to 100 parts by weight of the plasticizer, and further SP value) Is obtained by dissolving 20 to 200 parts by weight of a flame retardant aid having a half-life temperature of 100 ° C. to 250 ° C. with respect to 100 parts by weight of a plasticizer having an A of 8.3 or more and 9.4 or less. Supply the flame retardant solution into the aqueous suspension,
It is an expandable polystyrene resin particle for a heat insulating material used for an interior material of an automobile, wherein the polystyrene resin particle is impregnated with the flame retardant and a flame retardant aid.

  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 absorbed into the polystyrene resin seed particles by supplying the styrene monomer continuously or intermittently while heating and stirring in the autoclave. For example, 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 0.5 to 1.4 mm is more preferable. Furthermore, in the case of a heat insulating material used for an automobile interior material, 0.6 to 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, t-butyl peroxide, t- Butyl peroxypivalate, t-butyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxyacetate, 2,2- Organic peroxides such as bis (t-butylperoxy) butane, t-butylperoxy-3,3,5 trimethylhexanoate, di-t-butylperoxyhexahydroterephthalate, azobisisobutyronitrile, azo Azo compounds such as bisdimethylvaleronitrile These may be used alone or in combination of two or more.

  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.

  Further, in the above suspension polymerization method or seed polymerization method, when the styrene monomer is polymerized, the suspension is stabilized in order to stabilize the dispersibility of the styrene monomer droplets or the polystyrene resin seed particles. Examples of such suspension stabilizers include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, and polyvinyl pyrrolidone, and poorly water-soluble inorganic substances such as tricalcium phosphate and magnesium pyrophosphate. Examples include salts and the like, and an anionic surfactant is usually used together when a poorly water-soluble inorganic salt is used.

  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, an organic compound which has a boiling point below the softening point of a polystyrene resin and is gaseous or liquid 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 and isopropyl alcohol, dimethyl ether, diethyl ether and dipropyl ether , Low boiling point ether compounds such as methyl ethyl ether, inorganic gases such as carbon dioxide, nitrogen and ammonia, hydrocarbons having a boiling point of −45 to 40 ° C. are preferred, propane, n-butane, isobutane, n− Pentane and isopentane are more preferred . In addition, a foaming agent may be used independently or 2 or more types may be used together.

  Further, in the method for producing expandable polystyrene resin particles of the present invention, the polystyrene resin particles dispersed in the aqueous suspension are impregnated with 2,2-bis-plasticizer before or during impregnation with the foaming agent. [4- (2,3-Dibromoalkoxy) -3,5-dibromophenyl] -propane-dissolved flame retardant solution is supplied into the aqueous suspension, and the flame retardant is applied to the polystyrene resin particles. Impregnation 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.

  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. 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, the flame retardancy of the expandable resin particles may change. In many cases, it is preferably 0.2 to 2.0 parts by weight, more preferably 0.2 to 1.5 parts by weight, based on 100 parts by weight of the expandable polystyrene resin.

  The flame retardant solution is obtained by dissolving a powdered flame retardant in a plasticizer. Such a plasticizer is not particularly limited as long as it can dissolve a flame retardant, for example, diisobutyl adipate, diisononyl adipate, dioctyl phthalate, dibutyl phthalate in phthalate esters, Examples of the sebacic acid esters include one or more kinds such as dibutyl sebacate, and diisobutyl adipate is particularly preferable.

Examples of such plasticizers include organic substances having an SP value (Solubility parameter) of 8.3 or more and 9.4 or less, preferably adipic acid esters having an SP value of 8.5 or more and 9.2 or less, Particularly preferred are diisobutyl adipate (SP value: 8.9) (DIBA) and diisononyl adipate (DINA). The SP value of the present invention is calculated by substituting evaporation energy ΔE and molar volume V per unit volume of one molecule into the following equation.
(SP) 2 = ΔE / V

  And as said flame retardant, it should just be a powder form, when it exists in the state which does not melt | dissolve in another medium on the conditions impregnated in a polystyrene-type resin particle, 2,2-bis [4 among brominated phenol derivatives -(2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane, and 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane Most 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 40 to 300 parts by weight and preferably 50 to 270 parts by weight with respect to 100 parts by weight of the plasticizer.
In particular, 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane is preferably contained in an amount of 40 to 300 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 as to be preferably 0.4 to 2.5 parts by weight, and more preferably 0.5 to 2.0 parts by weight. This is because if the content of the flame retardant in the expandable polystyrene resin particles is small, the self-extinguishing property of the resulting polystyrene resin foam molded article may be deteriorated.

  The flame retardant having 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane contained in the plasticizer 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 in the plasticizer is not particularly limited. For example, after heating the plasticizer to a predetermined temperature, the powdered flame retardant is added to the plasticizer while stirring the plasticizer. The method etc. are mentioned.

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 sulfonate; alkylammonium acetates, alkyldimethylbenzylammonium salts, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylpyridinium salts, oxyalkylenealkylamines, polyoxyalkylenealkylamines, 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 an aqueous medium, it is sufficient that the powdered flame retardant is completely dissolved in the plasticizer and the plasticizer is dispersed in the aqueous medium. For example, it is necessary in the aqueous medium. Depending on the conditions, a surfactant or a hardly water-soluble inorganic salt is added and heated to a predetermined temperature, and then a powdered flame retardant and a plasticizer are added and stirred to dissolve the powdered flame retardant in the plasticizer. A method in which a flame retardant solution is formed and at the same time a flame retardant solution is dispersed in an aqueous medium, and a surfactant or a hardly water-soluble inorganic salt is added to the aqueous medium as necessary and heated to a predetermined temperature, while powder The flame retardant is dissolved in a plasticizer to prepare a flame retardant solution, and this flame retardant solution is supplied into the aqueous medium and stirred to disperse.

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.
And, the polystyrene resin particles dispersed in the aqueous suspension are impregnated with the foaming agent and the flame retardant. The present invention is excellent in environmental compatibility and flame retardancy, and further, the content of the flame retardant which is an organic additive The present invention relates to a foaming polystyrene-based resin particle for a heat insulating material and an automotive interior material, which are suitably used for automobile interior materials having a low content, particularly floor spacers, door pads, tool boxes and the like.
To produce expandable polystyrene resin particles, and then remove the expandable polystyrene resin particles from the aqueous suspension and, if necessary, subject the expandable polystyrene resin particles to a washing treatment and a drying treatment. Good.

  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, and the polystyrene resin pre-expanded particles are filled in the cavity of the mold, heated and foamed to expand the polystyrene resin. A molded body can be obtained.

  The average chord length of the foam is preferably 40 to 150 μm, and more preferably 50 to 120 μm. 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.

  When the density of the polystyrene-based resin foam molded article is low, the closed cell ratio of the polystyrene-based resin foam molded article is reduced, and the heat insulation and mechanical strength of the polystyrene resin foam molded article may be reduced. 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 resin foam molding may be lowered, so 0.01 to 0.08 g / cm 3 is preferable. Furthermore, 0.016 to 0.066 g / cm3 is preferable when used for automobile interior materials.

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 exchange water and 40 kg of styrene monomer were supplied, and the stirring blade was rotated at a rotation 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 maintained at 90 ° C. for 6 hours. The styrene monomer was subjected to suspension polymerization by raising the temperature to 120 ° C. and holding at 120 ° C. for 2 hours.

  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 0.6 to 0.85 mm and a weight average molecular weight of 300,000 were obtained.

  Next, after supplying 30 kg of ion exchange water, 4 g of sodium dodecylbenzenesulfonate, and 100 g of magnesium pyrophosphate to another 100 liter autoclave with a stirrer, 11 kg of the polystyrene particles were supplied as seed particles in the autoclave and stirred. Dispersed uniformly in water.

  In addition, a dispersion is prepared by dispersing 2 g of sodium dodecylbenzenesulfonate and 20 g of magnesium pyrophosphate in 6 kg of ion-exchanged water, while 132 g of benzoyl peroxide (purity 75%) as a polymerization initiator is added to 5 kg of styrene monomer. A styrene monomer solution in which 50 g of t-butylperoxy-2-ethylhexyl monocarbonate was dissolved was prepared, and this styrene monomer solution was added to the above dispersion and stirred using a homomixer to give an emulsion. To give an emulsion.

  Then, after heating and maintaining the autoclave at 75 ° C., the above emulsion is added to the autoclave, and the styrene monomer and benzoyl peroxide are absorbed into the polystyrene seed particles for 30 minutes. Then, 28 kg of styrene monomer was continuously dropped into the autoclave over 160 minutes while increasing the temperature in the autoclave from 75 ° C. to 108 ° C. at a rate of 0.2 ° C./min. Next, 20 minutes after the completion of dropping of the styrene monomer, the temperature is raised to 120 ° C. at a rate of 1 ° C./min and held for 90 minutes to obtain polystyrene particles by seed polymerization. It was. All styrene monomers were used for polymerization.

  2 g of ion-exchanged water is supplied with 6 g of sodium dodecylbenzenesulfonate and 112 g of magnesium pyrophosphate obtained by the metathesis method. (DIBA) (trade name “DI4A” manufactured by Taoka Chemical Industries, Ltd. 350 g, flame retardant 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane (Daiichi Kogyo Seiyaku Co., Ltd.) 310 g) and 130 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 MARK II fmodel manufactured by Tokushu Kika Kogyo Co., Ltd.). All of the flame retardant and flame retardant aid are dissolved therein to form a flame retardant solution. To form a dispersion of the flame retardant solution is dispersed in exchanged water. Then the autoclave after having cooled to 50 ° C. at a cooling rate of 1 ° C. / min, was fed the flame retardant solution into the autoclave.

  The autoclave was sealed 30 minutes after supplying the flame retardant solution into the autoclave, and then 3600 g of butane (isobutane / normal butane (weight ratio) = 30/70) as a blowing agent was applied under nitrogen pressure. The inside of the autoclave was heated to 100 ° C. in Table 1 and held at that temperature for 2 hours and 30 minutes.

  Then, cool the autoclave to 25 ° C. Taking out the expandable polystyrene particles from the autoclave, washing and dehydrating repeatedly, after passing through the drying step, classifying the flame retardant expandable polystyrene particles, the particle size is 0.90 to 1.4 mm, Thermoplastic expandable polystyrene particles having an average particle diameter of 1.1 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 had a good appearance.

(Example 2)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant was changed to 180 g instead of 310 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 had a good appearance.

(Example 3)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant was changed to 660 g instead of 310 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 had a good appearance.

Example 4
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the blowing agent impregnation temperature was 97 ° C. instead of 100 ° 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 had a good appearance.
(Example 5)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the foaming agent impregnation temperature was 103 ° C instead of 100 ° 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 had a good appearance.
(Example 6)
Expandable polystyrene particles were obtained in the same manner as in Example 1, except that the plasticizer was dibutyl sebacate (DBS) (SP value = 9.2) instead of isobutyl adipate.
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 had a good appearance.

(Comparative Example 1)
Except for replacing the flame retardant 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane with tetrabromobisphenol A-bis (2,3 dibromopropyl ether). In the same manner as in Example 1, expandable polystyrene particles were obtained.
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. However, in the combustion test of the obtained polystyrene foam molding, it burned and the self-extinguishing property was x.
(Comparative Example 2)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the flame retardant was changed to 130 g instead of 310 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 2 except that the flame retardant was changed to 1300 g instead of 310 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 300 μm, and the appearance of the foam was poor. Therefore, irregularities were observed in the fused part between the foamed particles of the foamable molded product.
(Comparative Example 5)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the blowing agent impregnation temperature was 120 ° C. instead of 100 ° C. When the average chord length of the obtained foamed molded product was measured, it was 30 μm, and the appearance of the foam was poor. Therefore, unevenness was observed in the fused part between the foamed particles of the foamable molded product.
(Comparative Example 6)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the plasticizer was dimethyl phthalate (SP value = 10.7) instead of diisobutyl adipate. However, when the obtained expandable polystyrene particles were pre-foamed, there were many deposits on the can wall in the pre-foaming machine, and there was a large amount of blocking where the foam particles were united, and as a result, a foam molded article was obtained. I couldn't.
(Comparative Example 7)
Expandable polystyrene particles were obtained in the same manner as in Example 1 except that the plasticizer was liquid paraffin (SP value = 7.5) instead of diisobutyl adipate. However, when the obtained expandable polystyrene particles were pre-foamed, there were many deposits on the can wall in the pre-foaming machine, and there was a large amount of blocking where the foam particles were united, and as a result, a foam molded article was obtained. I couldn't.

  About the obtained expandable polystyrene particles, the pre-expandability, foam moldability, combustibility, and the average chord length of the bubbles of the foam molded article were measured in the following manner, and the results are shown in Table 1 and Table 2. .

[Pre-foaming]
40000 g of the obtained expandable polystyrene particles, 20 g of polyethylene glycol as a surface treatment agent, 48 g of zinc stearate, 16 g of 12-hydroxystearic acid triglyceride (trade name “K-3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.) and stearic acid 28 g of monoglyceride (trade name “Riquemar S-100P” manufactured by Riken Vitamin Co., Ltd.) and 120 g of fatty acid triglyceride (trade name “Sunfat GTS-P” manufactured by Taiyo Kagaku Co., Ltd.) are supplied to a tumbler mixer and stirred for 30 minutes. The surface treatment agent was coated 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, 420 g of expandable polystyrene particles are supplied to a pre-foaming machine equipped with a stirrer and heated using steam to pre-expand. Thus, pre-expanded particles having a bulk ratio of 40 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. Measure according to the above, find the average value of the five test pieces, use it as the extinguishing time, and evaluate it comprehensively 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 having a length of 60 mm is drawn at an arbitrary position. The average chord length (t) of the bubbles is calculated from the number of bubbles existing on the straight line by the following formula.
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.

(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

Claims (5)

A plasticizer having a solubility parameter value (SP value) of 8.3 or more and 9.4 or less after dispersing polystyrene-based resin particles in an aqueous suspension and before or during impregnation with a foaming agent. 40-300 parts by weight of 2,2-bis [4- (2,3-dibromoalkoxy) -3,5-dibromophenyl] -propane as a brominated flame retardant with respect to parts is difficult to dissolve in the plasticizer. Supply the flame retardant solution into the aqueous suspension.
Expandable polystyrene resin particles used for automobile interior materials, wherein the polystyrene resin particles are impregnated with the flame retardant.   2. The expandable polystyrene resin particles used for an interior material of an automobile according to claim 1, wherein the plasticizer is an adipic acid ester, a phthalic acid ester or a sebacic acid ester. 3. Pre-expanded particles for use in an automobile interior material, wherein the expandable polystyrene resin particles used in the automobile interior material according to claim 1 or 2 are pre-expanded. An interior material for an automobile, which is a foamed molded article obtained by filling pre-expanded particles according to claim 3 into a mold and foaming, and having an average chord length of 40 to 150 µm. A polystyrene-based foam molded article obtained by filling the pre-expanded particles according to claim 3 into a mold and foaming,
The density of the polystyrene-based foam molded article is 0.016 to 0.066 g / cm3,
The average chord length of the foamed molded product is 40 μm to 150 μm,
The polystyrene foam molded article is an automotive interior material that is polystyrene resin particles having an average particle diameter of 0.6 mm to 1.2 mm.