JP2000256498A - Heat-resistant flame-retardant resin particle and foamed article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hear-resistant flame-retardant resin particle capable of imparting stabilized flame retardance with a small amount of a flame retarder without damaging the foamability, moldability and hear resistance, and foamed articles using the same. SOLUTION: The heat-resistant flame-retardant resin particles comprise foamable resin particles which are constituted by the monomer component composed of 50-80 wt.% styrene, 5-45 wt.% tricyclo [5, 2, 1, 02.6] deca-8-yl methacrylate, and 5-45 wt.% α-methylstyrene and 1-3 wt.%, based on the monomer component, tetrabromobisphenol A diallyl ether as the flame retardant, and the surfaces or the neighborhood of the surfaces of the heat-resistant flame retardant resin particles are coated with an inorganic ammonium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to expandable resin particles having good heat resistance and flame retardancy, and to a foam molded article using the same. More specifically, by coating inorganic ammonium on the surface of or near the surface of heat-resistant flame-retardant resin particles, excellent flame retardancy can be achieved with a small amount of flame retardant without impairing foamability, moldability and heat resistance. The present invention relates to a heat-resistant flame-retardant resin particle and a foamed molded article having the same.

[0002]

2. Description of the Related Art Conventionally, styrene-based resin particles have been used as a cover of a hot water pipe or a heat insulating material thereof because of excellent heat insulating properties. However, styrene-based resins have poor heat resistance, so they are used in applications requiring heat resistance higher than the softening temperature of styrene-based resins, such as thermal insulation for heat pipes, metal roof insulation in buildings, bathroom insulation, and automotive roof insulation. Could not be used. In addition, styrene resin foams have a drawback that they are easily flammable due to their structure, and cannot be used in application fields requiring flame retardancy such as building materials.

[0003] Various attempts have been made to improve the heat resistance. For example, a blend with a heat-resistant polymer such as high-density polyethylene or crystalline polypropylene is used as the base resin (JP-A-54-6316, JP-A-54-63195, JP-A-52-10).
No. 1268) has been proposed, but in this case, the moldability is deteriorated due to the difficulty in mixing with the styrene resin and the poor retention of the readily volatile foaming agent, and a good-quality foam cannot be obtained. And so on.

Further, there is disclosed an example in which a styrene-maleic anhydride copolymer is used in these resins to improve heat resistance (Japanese Patent Application Laid-Open No. 47-39186). Requires a very complicated suspension polymerization process due to the strong reactivity of maleic anhydride, and the resin component has good adhesion to metal roofs, so there was difficulty in mold release during molding. .

JP-A-60-206846, 206
No. 847 and No. 206848 disclose a copolymer containing α-methylstyrene and acrylonitrile as main components. However, when acrylonitrile is copolymerized, the fluidity of resin particles is reduced, so that a high foaming property is obtained. It was difficult to give.

[0006] Known flame retardants for styrene resin particles include relatively low molecular weight and low melting point compounds such as tetrabromoethane, hexabromocyclododecane, tribromophenol, and tetrabromobisphenol A. Organic brominated flame retardants are known. Various methods for flame retarding such as before coating, during polymerization, after polymerization, and surface coating on resin particles have been studied.

[0007] The addition of a flame retardant during the polymerization has disadvantages such as a decrease in the polymerization rate and yield, and an uneven impregnation of the flame retardant. For this reason, in order to impart sufficient flame retardancy, a large amount of flame retardant is required, and it has been difficult to say that it is economical. Also, the use of a large amount of a flame retardant causes a decrease in foaming property, workability and heat resistance of a molded article due to generation of blocking during prefoaming.

[0008]

SUMMARY OF THE INVENTION The present invention provides heat resistance,
An object of the present invention is to provide heat-resistant and flame-retardant resin particles which can have stable flame retardancy with a small amount of a flame retardant without impairing the foamability and moldability, and a foam molded article using the same.
That is, the present invention, by coating the surface of the heat-resistant flame-retardant resin particles containing a volatile foaming agent with inorganic ammonium, foamability, moldability, without impairing the heat resistance, and stable with a small amount of flame retardant They have been found to impart flame retardancy.

[0009]

Means for Solving the Problems points invention, the monomer component constituting the foamable resin particles, styrene 50-80% by weight, methacrylic acid tricyclo [5,2,1,0 ^2.6] dec -8 -Yl is 5 to 45% by weight and α-methylstyrene is 5 to 45% by weight, and a flame retardant is added to the monomer component based on tetrabromobisphenol A diallyl ether 1 to 3.
The present invention relates to heat-resistant flame-retardant resin particles in which the surface or near the surface of the heat-resistant flame-retardant resin particles is coated with an inorganic ammonium salt.

In the present invention, it is preferable that the surface or near the surface of the heat-resistant and flame-retardant resin particles is coated with ammonium phosphate.

In the present invention, the ammonium phosphate is used in an amount of 0.05 to 0.5 with respect to the heat-resistant and flame-retardant resin particles.
It is preferable that the coating is performed in a weight%.

The present invention relates to a foam molded article obtained by subjecting the above-mentioned heat-resistant flame-retardant resin particles to foam molding using 3 to 10% by weight of a readily volatile foaming agent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the heat-resistant and flame-retardant resin particles of the present invention and a foam molded article using the same will be described in detail.

(1) Method for Producing Heat-Resistant Flame-Retardant Resin Particles An aqueous flame-retardant solution is prepared in which tetrabromobisphenol A diallyl ether present in an aqueous surfactant solution is further uniformly and finely dispersed by a stirrer. I do. The obtained aqueous solution of the flame retardant is dispersed in tricyclo [5,2,1,0
^2.6 ] A heat-resistant polystyrene resin particle composed of deca-8-yl, α-methylstyrene and styrene is added to a stirred autoclave in which a surfactant and an aqueous dispersant are present,
6 to 6 at the impregnation temperature of 70 to 125 ° C.
The impregnation is performed for 10 hours.

The composition ratio of the heat-resistant resin particles used in the present invention is such that styrene is 50 to 80% by weight and 50 to 80% by weight.
Resin particles comprising 70% by weight are preferred. Tricyclo [5,2,1,0 ^2.6 ] dec-8-yl methacrylate is 5
To 45% by weight, preferably 5 to 20% by weight. Also, α-methylstyrene is 5 to 45% by weight.
And resin particles comprising 5 to 20% by weight are preferred.

The flame retardant used in the present invention is tetrabromobisphenol A diallyl ether, and preferably has a fine and uniform particle diameter of the flame retardant. More preferably, the flame retardant tetrabromobisphenol A diallyl ether has an average particle diameter of 100 microns or less. The amount used is tetrabromobispheno-
The amount of diallyl ether is from 1 to 3% by weight, preferably from 1 to 2% by weight, based on the monomer component.

The softening agent used in the present invention has a boiling point of 150 ° C. lower than that of the resin particle composition.
C. or less is preferred. For example, aromatic hydrocarbons such as ethylbenzene, toluene, styrene, benzene and xylene 1.2 halogenated hydrocarbons such as dichloropropane and trichloroethylene, dioctyl adipate vegetable oil, dibutyl sebacate and the like can be mentioned. The amount of the softener is preferably 0.05 to 3% by weight based on the monomer component,
~ 3% by weight is more preferred.

As the foaming agent in the present invention, a volatile organic compound which is liquid or gas at normal pressure and normal temperature and does not dissolve resin particles is used. Examples of such a compound include aliphatic hydrocarbons such as propane, butane, normal butane, isobutane, isopentane, and normal pentane, and cycloaliphatic hydrocarbons such as cyclohexane and cyclopentane. The amount of the foaming agent to be used is 3 to 10% by weight based on the monomer component, preferably 3 to 10% by weight.
８8% by weight. The obtained heat-resistant flame-retardant resin particles are subjected to dehydration, drying and classification, and then coated with a surface additive.

(2) Coating Method of Surface Additive On the surface or near the surface of the obtained heat-resistant and flame-retardant resin particles,
Coat ammonium monophosphate. As ammonium phosphate used in the present invention, ammonium monophosphate, diammonium phosphate, ammonium tertiary phosphate and ammonium polyphosphate are used, but ammonium monophosphate is preferred from the working environment.

The ammonium monophosphate used in the present invention has two types of appearance, crystalline and fine powder, and fine powder is preferred. More preferably,
It is preferable that the particle diameter of ammonium monophosphate is 100 microns or less. The amount of ammonium monophosphate used is 0.05 to 0.5 with respect to the heat-resistant flame-retardant resin particles.
% By weight, more preferably from 0.05 to 0.3% by weight. Further, since ammonium monophosphate is easily dissolved in water and hot water, it can be coated as an aqueous solution of ammonium monophosphate.

In addition, such a coating agent can be used in combination with a surfactant used as zinc stearate, triglyceride stearate, monoglyceride stearate, hydrogenated castor oil, amide compound, antistatic agent and the like. The coating of the foamed particles with the surface coating agent can be performed by a Henschel mixer, a Lady Ge mixer or the like.

The foaming of the expandable resin particle composition according to the present invention is carried out by steam, hot air, hot water or the like. As the method, a general styrene resin foaming method can be applied. Foaming ratio of the foamable resin composition according to the present invention,
It can be arbitrarily selected from low magnification to high magnification.

The foam molded article obtained from the expandable resin particles according to the present invention is used as a solar-related heat insulating material, a hot water tank heat insulating material, a metal roof heat insulating material, a food container heat insulating material, a vehicle ship. There are thermal insulation, hot water pipe insulation, sizing board, automobile-related structural material, metal simultaneous molding panel molding and the like.

[0024]

Next, the present invention will be described in more detail by way of examples.

The evaluation in the present invention was performed as follows. Amount of bromine in gas: After burning the gas, the bromine content was measured by ion chromatography. Amount of blocking generated during prefoaming: The amount of blocking generated during prefoaming was investigated. Dimensional change rate: The foamed particles were foamed 40 times (ml / g), cured at 60 ° C. for 3 days, room temperature for 3 days, and then cured.
The specimen was cut into a specimen of × 100 × 25 (mm). The test piece was left in an atmosphere of 95 ° C. for 168 hours, and the dimensional shrinkage at that time was determined. Self-extinguishing time: based on JIS A9511.

Example 1 <Preparation of heat-resistant resin particle composition> In a 16-liter autoclave equipped with a stirrer, 6000 g of pure water, 9 g of tricalcium phosphate, and 0.24 of sodium dodecylbenzenesulfonate were added.
g and 4.2 g of sodium sulfate were charged and stirred at 200 rpm. Subsequently, 4200 g of styrene and tricyclo [5,2, methacrylate] were similarly stirred.
1,0 ^2.6 ] dec-8-yl (manufactured by Hitachi Chemical Co., Ltd., FA-
513M) 900 g, α-methylstyrene 900 g,
1.1. Bis (t-butylperoxy) 3,3,5 trimethylcyclohexane (Nippon Resin, Perhexa 3M)
30 g, t-butyl peroxyisocarbonate
0 g and ethylene bisamide (3.0 g) were mixed and dissolved. After the charging was completed, the temperature was raised to 93 ° C. Three hours and four hours after completion of the temperature increase, tricalcium phosphate was added to each of 3.0 hours.
g and 6.0 g were added. Subsequently, the temperature was maintained at 93 ° C. for 3 hours, and when the polymerization proceeded to 90%, 6.0 g of tricalcium phosphate was added. Then, the temperature was raised to 115 ° C., and the temperature was maintained for 4 hours to complete the polymerization. Next, the slurry was cooled to 40 ° C., and the removed slurry was washed, dehydrated and dried.
Classification was performed with 2 mesh passing and 26 mesh remaining.

<Preparation of Flame Retardant Dispersion> To 6000 g of the obtained heat-resistant resin particles, 120 g of tetrabromobisphenol A diallyl ether having an average diameter of 70 μm (Frame cut 122 k, manufactured by Toso) was added to dodecylbenzene sulfone. 500 g of an aqueous solution containing 6.0 g of acid soda was dispersed by a homomixer (Model 4D, manufactured by Tokushu Kogyo Co., Ltd.) for 30 minutes. <Blowing agent impregnation step> A resin having a particle size of 0.7 to 1.0 mm was added to an autoclave with a 16-liter stirrer, 360 g of tricalcium phosphate and 6.0 g of sodium dodecylbenzenesulfonate, and 6000 g of pure water. 6000 g of particles were charged, and the flame retardant dispersion was added with stirring. After the preparation,
Toluene 90 as a softening agent for 6000 g of resin particles
g of an aqueous solution containing 6.0 g of sodium dodecylbenzenesulfonate and a homomixer (MO manufactured by Tokushu Kogyo Kogyo Co., Ltd.)
(DEL40) for 20 minutes, and added to the autoclave over 60 minutes. After the addition is complete,
After the temperature was raised, 480 g of a foaming agent composed of 40% by weight of propane and 60% by weight of butane was added over 60 minutes.
After 60 minutes, the temperature was raised to 120 ° C. over 90 minutes, and the temperature was maintained for 8 hours, then cooled to 40 ° C. and taken out of the autoclave. Then, after dehydration and drying, pass through 12 mesh 2
Classification was performed with 6 mesh remaining. <Post-treatment step> For 6000 g of the obtained resin particles, 18 g of ammonium monophosphate and an antiblocking agent 12
g and 3.0 g of castor hardened oil, to obtain heat-resistant and flame-retardant resin particles. <Evaluation of molded article> The obtained heat-resistant flame-retardant resin particles were pre-foamed to a bulk density of 0.025 g / ml using steam as a heat medium, aged, and then foamed to obtain a molded article. Table 1 shows the test results obtained by measuring the amount of flocking generated during prefoaming, 95 ° C., dimensional shrinkage, self-extinguishing time, and the bromine content in the paste.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that the flame retardant tetrabromobisphenol A diallyl ether was used in an amount of 180 g and was not coated with ammonium monophosphate in the post-treatment step. Table 1 shows the results. Comparative Example 2 Table 1 shows the test results measured in the same manner as in Example 1 except that the monoammonium phosphate was not coated in the post-treatment step. Comparative Example 3 The same procedure as in Example 1 was carried out except that the flame retardant tetrabromobisphenol A diallyl ether was used in an amount of 30 g, and the post-treatment step was coated with 30 g of ammonium monophosphate.
Table 1 shows the test results.

[0029]

[Table 1]

[0030]

According to the present invention, there are provided heat-resistant and flame-retardant resin particles and foamed molded articles which impart stable flame retardancy with a small amount of a flame retardant without impairing foamability, moldability and heat resistance. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C08L 25/08 C08L 25/08 (72) Inventor Tetsuya Kato 14 Goi Minamikaigan, Ichihara-shi, Chiba Prefecture Hitachi Chemical Co., Ltd. F-term in Goi factory (reference) 4F074 AA32 AC31 AF01 BA35 BA36 BA37 BA38 BA39 BA40 BB28 CA34 CC47 4J002 BC071 BC091 BG071 DH047 ED077 FB071 FD136 GL00

Claims (4)

[Claims] 1. A monomer component constituting the foamable resin particles, styrene 50-80% by weight, methacrylic acid tricyclo [5,2,1,0 ^2.6] dec-8-yl 5-45 wt% and α-methylstyrene comprising 5-45% by weight,
The flame retardant is added to the monomer component with tetrabromobispheno-
Heat-resistant flame-retardant resin particles containing 1 to 3% by weight of diaryl ether, wherein the surface or near the surface of the heat-resistant flame-retardant resin particles is coated with an inorganic ammonium salt. 2. The heat-resistant flame-retardant resin particles according to claim 1, wherein the surface or near the surface of the heat-resistant flame-retardant resin particles is coated with ammonium phosphate. 3. The ammonium phosphate according to claim 2,
Heat-resistant flame-retardant resin particles coated with 0.05 to 0.5% by weight based on the heat-resistant flame-retardant resin particles. 4. A foam molded article obtained by subjecting the heat-resistant and flame-retardant resin particles according to claim 1 to foam molding by using 3 to 10% by weight of a volatile foaming agent.