JP3397768B2 - Flame retardant styrenic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrene resin composition having good flame retardancy, and more particularly to a resin composition capable of reducing a glowing glowing time during combustion.

[0002]

2. Description of the Related Art Conventionally, in order to impart flame retardancy to a styrene resin composition, a halogen-based, phosphorus-based or inorganic flame-retardant is added to the composition. The flame-retardant effect required for UL-94 VO level generally improves as the flame-retardant is added, but the use of a large amount of flame-retardant increases the specific gravity of the resin, resulting in high weight per unit volume and cost of the molded product. Become. On the other hand, for the composition itself, a large amount of flame retardant not only lowers the impact strength of the resin, but also causes deterioration of physical properties such as thermal stability. In addition, the production cost is increased by adding a large amount of flame retardant.

The flame retardant is described in, for example, JP-A-59-16.
No. 6552 has a halogen-based flame retardant, antimony oxide (Sb ₂ O ₃ ) composition, and a small amount of ethylenebisstearylamide (EBA) in a styrene resin with a specific viscosity (more than 0.4 dl / g).
Is disclosed. Although this method improves the flame retardancy, it has a drawback that the red-hot combustion phenomenon during combustion is prolonged.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a styrene resin composition having good flame retardancy and capable of reducing the red hot combustion time during combustion.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned drawbacks, the present inventor has identified the molecular weight distribution of tetrahydrofuran-soluble component of styrene resin, and It has been found that by specifying the contents of halogen (particularly bromine) and antimony, the resin composition is provided with good flame retardancy and the red heat burning time during combustion is reduced.

The present invention contains (A) a rubber-modified styrene resin [hereinafter referred to as (A) component], (B) a brominated flame retardant [hereinafter referred to as (B) component], and (C) antimony. A flame-retardant styrenic resin composition containing an oxide [hereinafter referred to as (C) component], wherein the ratio X (% by weight) of the tetrahydrofuran-soluble component of (A) having a molecular weight of 2,000 to 50,000. ) Is less than 25% by weight, and this ratio X
And the ratio Y (% by weight) of those having a molecular weight of 1,000,000 or more satisfy the relationship of X / Y ^1.5 ≤ 10.5, and the bromine content (as bromine atom) in the composition is 8.5% by weight or more and the antimony content (antimony atom). As 1.0) to 1.0% by weight of the flame-retardant styrenic resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber-modified styrene resin as the component (A) is obtained by graft-polymerizing an aromatic vinyl monomer and another monomer copolymerizable with the aromatic vinyl monomer in the presence of a rubber-like polymer. It is also possible to use the one obtained by kneading the above-mentioned graft copolymer with the above-mentioned graft copolymer, which contains the above-mentioned graft copolymer. The polymerization method is a bulk polymerization method,
A solution polymerization method, a combined use of a bulk solution polymerization method and a suspension polymerization method and the like can be mentioned.

Examples of the aromatic vinyl monomer include styrene, orthomethylstyrene, paramethylstyrene, metamethylstyrene, 2,4-dimethylstyrene, ethylstyrene, para-t-butylstyrene, and other alkyl-substituted styrene, α-methyl. Examples include styrene, α-alkyl-substituted styrenes such as α-methyl-paramethylstyrene, and bromo-substituted styrenes such as bromostyrene, dibromostyrene, and 2,4,6-tribromostyrene. Of these, styrene and α-methylstyrene are more preferable. The above styrenic monomers can be used alone or in combination.

In the present invention, an aromatic vinyl monomer,
Preferably the units of styrenic monomer preferably account for 98-60% by weight of component (A), more preferably 96
~ 70% by weight.

Other monomers copolymerizable with the aromatic vinyl monomer include unsaturated nitriles (eg acrylonitrile), (methyl) acrylic acid esters (eg methyl methacrylate, butyl acrylate),
Acrylic acid, maleic anhydride, maleimide (eg N-phenylmaleimide) and the like can be mentioned. The unit of the other copolymerizable monomer is preferably a component of the component (A).
It accounts for 0 to 20% by weight.

The rubber-like polymer may be a general rubber applied to impact-resistant styrenic resins, such as natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene rubber, styrene-isoprene rubber-like copolymer. Coalesce, butyl rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber and the like, butadiene rubber,
Styrene-butadiene rubber, isoprene rubber and ethylene-propylene-diene rubber are preferred. These rubber polymers can be used alone or in combination of one or more. Among them, polybutadiene rubber includes high cis type having a high cis-1,4 bond content and low cis type having a low cis content.
The rubbery polymer preferably accounts for 2 to 20% by weight, and preferably 4 to 15% by weight in the component (A).

Rubber-modified styrene type component (A) of the present invention
Resin is soluble in component (A), tetrahydrofuran (THF)
In the minutes, the ratio X (heavy
%) Is 25% by weight or less, and this ratio X and THF soluble content are
With the ratio Y (% by weight) of those having a molecular weight of 1,000,000 or more
Is X / Y^1.5The relationship of ≦ 10.5 is satisfied. Ratio X is good
23 wt% or less, more preferably 21 wt% or less
It Also, preferably X / Y ^1.5≤10.0, more preferably
Is X / Y^1.5≦ 9.0. Ratio X exceeds 25% by weight
I'm X / Y^1.5If> 10.5, extinguish flames during combustion test
After burning, the red-hot combustion phenomenon is likely to occur. This molecular weight
Is the weight average molecular weight.

As a result of earnest studies by the present inventors, it was found that the cause of red heat combustion was due to the combined effect of the low molecular weight portion and the high molecular weight portion in the component (A). That is, if the low molecular weight portion is too much or the high molecular weight portion is too small in the component (A), a red-hot combustion phenomenon occurs. In addition, the reason why the ratio X of the low molecular weight portion is limited to 25% by weight or less in the present invention is that when this ratio exceeds 25% by weight, the overall viscosity decreases, and even if the ratio Y of the high molecular weight portion is increased, modification is performed. This is because the effect will not improve. Therefore, X / Y ^1.5 ≤ 10.5 and X is 25% by weight
The effect of effectively preventing the red hot combustion phenomenon of the resin composition is exhibited only when the following relationships are satisfied at the same time.

In the present invention, the THF-soluble component as the component (A) means an insoluble substance (or gel-like substance) in which the rubber-modified styrene resin as the component (A) is dissolved in THF and which is insoluble in the filter. It is obtained by excluding.

In the present invention, the ratio of the component (A) in the composition is 40 to 95% by weight, more preferably 50 to 90% by weight, and particularly preferably 60 to 85% by weight.

As the brominated flame retardant of the component (B) of the present invention, tetrabromobisphenol A, tetrabromobisphenol A bis (2-hydroxyethyl ether), tetrabromobisphenol A bis (2,3-dibromophenyl ether) Tetrabrom bisphenol A derivatives such as In addition, there are hexabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether (abbreviation DE-83), bis (tribromophenoxy) ethane, hexabromocyclododecane, and brominated epoxy resin flame retardants. This brominated epoxy resin flame retardant is obtained by reacting brominated bisphenol A with 3-chloro-1,2-epoxypropane. Further, a high molecular weight brominated epoxy resin having an epoxy group or a phenol group at the terminal obtained by reacting a bromine-containing epoxy resin with a bromine-containing bisphenol A can also be used in the present invention. In addition, the epoxy group contained in the brominated epoxy resin, phenol,
Also used are those in which the terminal group obtained by reacting with alkylphenol, brominated phenol, tribromophenol, trichlorophenol, pentabromophenol, pentachlorophenol, etc. is phenyl etherified.

As the brominated flame retardant of the component (B) of the present invention, those represented by the following structural formulas are preferable.

[0018]

[Chemical 1]

R in the above structural formula is a hydrogen atom or the following group.

[0020]

[Chemical 2]

Here, R'is lower (preferably having 1 carbon atom).
To 5) phenyl group substituted with an alkyl group or a bromine atom, X
Is a bromine atom, i is an integer of 1 to 4, and n is an integer of 0 to 30.

Other brominated flame retardants used in the present invention include bromophenol, tribromophenol,
Pentabromphenol, tribromocresol, dibromoisopropylphenol, tetrabromobisphenol S, brominated trimethylphenylindane and the like can be mentioned.

In the present invention, the bromine content in the composition is not less than 8.5% by weight, preferably 9.0 to 18% by weight, more preferably 9.5% to achieve the flame retardancy standard of UL-94 VO level. ~ 13% by weight. When the bromine content is lower than 8.5% by weight, the burning seconds are rapidly increased during the burning test and UL-9
4 Does not reach VO level flame retardancy.

The oxide containing antimony of the component (C) of the present invention is used as a flame retardant aid, and the content of antimony occupies 1.0 to 4.0% by weight of the resin composition, preferably 1.5 to
It is 3.7% by weight, more preferably 2.0 to 3.5% by weight. Specific antimony oxides include diantimony trioxide, diantimony pentoxide, etc., but the effect is that the bromine compound exerts an auxiliary effect when suppressing the combustion mechanism, and antimony is contained in the composition. UL-94 VO level requirements will not be reached if the amount becomes insufficient, but a certain effect will be exhibited if it exceeds a certain ratio. However, on the contrary, if the ratio is too high, for example, 4.0% by weight in the resin composition.
Above, the red-hot combustion phenomenon warps and increases. Although the mechanism is not clear, it is considered to be a phenomenon caused by the accumulation of heat quantity in metal ions, and it is considered that the agglomerated antimony oxide forms a heat concentration point and the red heat combustion phenomenon occurs continuously.

If desired, other additives may be added to the flame-retardant styrene resin composition of the present invention. For example, carbon black or the like is added to the resin when producing a black molded product. However, when carbon black is added to the composition, the red-hot combustion phenomenon of the resin composition becomes more prominent, so the amount of carbon black added is generally preferably 0.125 to 2.0% by weight in the composition. Other additives include antioxidants, UV absorbers, lubricants, fillers, plasticizers and antistatic agents.

Examples of the antioxidant used in the present invention include 2,6-di-t-butyl-4-methylphenol, trinonylphenylphosphite, octadecyl-3- (3,5-di-t-).
Butyl-4-hydroxyphenyl) propionate, thiodiethylenebis (3,5-di-t-butyl-4-hydroxyhydrocinnamate), tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinna) Mate)] methane, 2,
4-bis [(octylthio) methyl] orthocresol,
Tris (2,4-di-t-butylphenyl) phosphite, di-
Lauryl thiodipropionate, distearyl thiodipropionate, triethylene glycol bis 3- (3-t-
Butyl-4-hydroxy-5-methylphenyl) propionate, 1,1-bis (2-methyl-4-hydroxy-5-t
-Butylphenyl) butane and the like.

As the lubricant used in the present invention, metal stearate such as calcium stearate, magnesium stearate and zinc stearate, ethylenebisstearylamide (abbreviation EBA), methylenebisstearylamide, palmitylamide, butyl stearate, Compounds such as palmityl stearate, polypropylene glycol monostearate, behenic acid and stearic acid, polyethylene wax, montan wax and the like can be mentioned.

The resin composition of the present invention is obtained by kneading the styrene resin as the component (A), the brominated flame retardant as the component (B), the antimony oxide as the component (C), and other additives. As a kneading method for obtaining the resin composition of the present invention, there is a method of dry-blending with a Henschel mixer or the like and then melt-kneading with a kneader such as an extruder, a kneader, or a Banbury mixer.

When the melt kneading is carried out by the above-mentioned mixing method, or when the resin composition of the present invention is subjected to a thermal history at the time of molding by the molding method described later, there is a possibility that thermal decomposition or dehydrohalogenation reaction may occur. Therefore, it is necessary to keep the kneading temperature and the molding processing temperature within the range of 180 to 250 ° C. Molding methods generally applied when molding is performed using the resin composition of the present invention include an injection molding method, an extrusion molding method, a compression molding method and a hollow molding method.

[0030]

EXAMPLES <Physical property test> (1) The average molecular weight and the molecular weight distribution (A) component were measured under the following conditions based on gel permeation chromatography (GPC). Column: KD-806M Detector: RI-410, UV-486 Mobile phase: Tetrahydrofuran (THF), Flow rate 1.0cc / min In the GPC measurement chart, the integrated total area of 2,000 to 12,000,000 molecular weight is 100%, and the molecular weight is 2,000. The integrated area in the range of up to 50,000 is X, and the integrated area having a molecular weight of 1,000,000 or more is Y.

(2) Impact strength (IZ) According to ASTM D-256 (notched, thickness 1/8 inch). The unit is kg-cm / cm.

(3) Tensile strength (Tsy) Measured according to ASTM D-638. The unit is kg / cm ² .

(4) Combustion test According to the UL-94 VO measurement standard, flame burning was performed using a test piece (125 mm × 13 mm × 2.5 mm) of a flame-retardant styrene resin composition, and the burning time was measured. Those that passed are "○",
Those that cannot pass are indicated by "x".

(5) Red-hot burning time This is represented by the number of seconds of combustion of the extra flame in the burning test. That is, it is the number of seconds until the remaining sparks are continuously burned and completely extinguished after the flame on the test piece is extinguished during the combustion test.

<Production Example> Production Example 1 [Production of rubber-modified styrene resin (A-1)] 86% by weight of styrene monomer, 7% by weight of ethylbenzene, 6.675% by weight of polybutadiene rubber (low cis butadiene rubber, Mooney viscosity is 35 cps, molecular weight is 450,00
0, vinyl-based structure 12% by weight), 0.3% by weight 2,6-
Mixing raw material consisting of di-t-butyl-4-cresol and 0.025% by weight of initiator (t-butylperoxyisopropyl carbonate), using a pump, three plugs with a flow rate of 50 liters per hour and a volume of 110 liters each Send to a flow type reaction tank. The reaction temperature gradually increases from 105 ° C to 175 ° C. A product with a final conversion of 72% by weight is obtained. After the solvent was removed from the above product, a rubber-modified styrene resin (A-1) was obtained.

Production Example 2 [Rubber-modified styrene resin (A-
2) Production] 85.7% by weight of styrene monomer, 7% by weight of ethylbenzene, 7.035% by weight of polybutadiene rubber (the same as in Production Example 1), 0.25% by weight of octadecyl-3- (3,5-di-t-).
Butyl-4-hydroxyphenyl) propiolate, 0.015
50% of compounded material consisting of wt.
It is sent to a three-plug flow type reaction tank with a volume of 110 liters and a volume of 110 liters. Reaction temperature gradually increases from 105 ℃ to 1
Raise it to 90 ° C. A product with a final conversion of 81% by weight is obtained. After the solvent was removed from the product, a rubber-modified styrene resin (A-2) was obtained.

Production Example 3 [Rubber-modified styrene resin (A-
3) Production] The production method is the same as in Production Example 2, but the styrene monomer in the blended raw material is changed to 84.7% by weight, and a high molecular weight of 1.0% by weight
1,700,000) polystyrene was added to obtain a rubber-modified styrene resin (A-3).

Production Example 4 [Rubber-modified styrene resin (A-
4) Production] The production method is the same as in Production Example 2, but the styrene monomer in the compounded raw material is changed to 84.7% by weight, and the high molecular weight (molecular weight
1,700,000) polystyrene was added and the temperature in the third reaction tank was raised to 205 ° C. to obtain a rubber-modified styrene resin (A-4) having a final conversion of 90% by weight.

Production Example 5 [Rubber-modified styrene resin (A-
Production of 5)] The same composition and production method as in Production Example 2, except that the styrene monomer in the raw material composition is changed to 80.7% by weight, 5.0% by weight of medium molecular weight polystyrene (molecular weight 420,000) is added, and the rubber-modified styrene resin ( A-5) was obtained.

Production Example 6 [Rubber-modified styrene resin (A-
6) Production] 85.4% by weight of styrene monomer, 4% by weight of ethylbenzene, 7.5% by weight of polybutadiene rubber (Hicis rubber, Taiwan Synthetic Rubber Taipol-015H), 0.05% by weight of octadecyl-3- (3,5-) Di-t-butyl-4-hydroxyphenyl) propiolate, 3.02% by weight of mineral oil, and 0.03% by weight of an initiator were used as raw material compositions and reacted in the same manner as in Production Example 1 to produce a rubber-modified styrenic resin (A- 6) was obtained.

Production Example 7 [Rubber-modified styrene resin (A-
Production of 7)] The same composition and production method as in Production Example 2, except that the initiator in the blended raw material is
0.015% by weight, styrene monomer was changed to 85.415% by weight, the temperature in the third reaction tank was raised to 185 ° C., and the final conversion rate was about 85% to obtain a rubber-modified styrene resin (A-7).

<Example> Example 1 78.5% by weight of styrene resin (A-1) and 17.0% by weight of brominated epoxy resin (hereinafter referred to as EC-14. Dainippon Ink and Chemicals, bromine content 58.5%) , A flame retardant with a molecular weight of 1,400), 3.5 wt% diantimony trioxide (Sb ₂ O ₃ ), and 1.
0% by weight of carbon black is uniformly melt-kneaded in an extruder. After kneading, the molten resin is extruded from a strand die, cooled in a water tank and then cut into pellets. This pellet is pre-dried and then 1/1 with an injection molding machine.
A 0-inch UL combustion test piece and a physical property test piece are molded and the above-mentioned physical properties and combustion test are performed. The results are shown in Table 1.

Example 2 The same production method as in Example 1 was used, but using A-6 as a styrene resin.
It was used. The evaluation results are shown in Table 1.

Example 3 The same production method as in Example 1 was used, but 79.0% by weight of a styrene resin (A-3) was used, and the amount of antimony trioxide used was 3.
Changed to 0% by weight. The evaluation results are shown in Table 1.

Example 4 The same manufacturing method as in Example 1 was used, but the raw material composition was 84.1% by weight of styrene resin (A-1) and 10.8% by weight of decabromodiphenyl ether (flame retardant, hereinafter referred to as DE-83). ,
4.1 wt% diantimony trioxide and 1.0 wt% carbon black. The evaluation results are shown in Table 1.

Example 5 In Example 4, the raw material composition was changed to styrene resin (A-
1) was 82.0% by weight, DE-83 was 14.0% by weight, and diantimony trioxide was 3.0% by weight. The evaluation results are shown in Table 1.

Example 6 In Example 4, the raw material composition was changed to styrene resin (A-
1) was 83.0% by weight, DE-83 was 14.0% by weight, diantimony trioxide was 3.0% by weight, and carbon black was not used. The evaluation results are shown in Table 1.

Comparative Example 1 The same production method as in Example 1 was used, but A-2 was used as a styrene resin.
It was used. The evaluation results are shown in Table 1.

Comparative Example 2 The same production method as in Example 1 was used, but using A-7 as a styrene resin.
It was used. The evaluation results are shown in Table 1.

Comparative Example 3 In the same production method as in Example 1, the styrene resin in the raw material composition was changed from (A-1) to 79.0% by weight (A-4), and the amount of diantimony trioxide used was 3.0% by weight. Changed to%. The evaluation results are shown in Table 1.

Comparative Example 4 The same production method as in Example 1 was used, but the amount of styrene resin (A-1) used in the raw material composition was changed to 77.0% by weight, and the amount of diantimony trioxide used was changed to 5.0% by weight. . The evaluation results are shown in Table 1.

Comparative Example 5 The same production method as in Example 1 was used, but the raw material composition was 74.9% by weight of styrene resin (A-6), 20.0% by weight of EC-14, 4.1% by weight of antimony trioxide, and 1.0% by weight. Of carbon black. The evaluation results are shown in Table 1.

Comparative Example 6 The same production method as in Example 4 was used, but the amount of styrene resin (A-1) used in the raw material composition was changed to 82.7% by weight, and the amount of diantimony trioxide used was changed to 5.5% by weight. . The evaluation results are shown in Table 1.

Comparative Example 7 The same manufacturing method as in Example 4 was used, but the raw material composition was 82.0% by weight of styrene resin (A-2), 14.0% by weight of DE-83, and 3.0% by weight of diantimony trioxide. The evaluation results are shown in Table 1.

Comparative Example 8 The same production method as in Example 4 was used, but the raw material composition was 79.2 wt% styrene resin (A-4), 16.0 wt% DE-83, 3.8 wt% diantimony trioxide, and 1.0 wt%. Of carbon black. The evaluation results are shown in Table 1.

Comparative Example 9 The same manufacturing method as in Example 4 was used, but the raw material composition was 82.0% by weight of styrene resin (A-5), 14.0% by weight of DE-83, 3.0% by weight of antimony trioxide, and 1.0% by weight. Of carbon black. The evaluation results are shown in Table 1.

Comparative Example 10 The same production method as in Example 4 was used, but the raw material composition was 80.2% by weight of styrene resin (A-4), 16.0% by weight of DE-83, and 3.8% by weight of diantimony trioxide. The evaluation results are shown in Table 1.

Comparative Example 11 The same production method as in Example 1 was used, but the raw material composition was 83.5 wt% styrene resin (A-1), 12.0 wt% flame retardant EC-14 (bromine content 7.0 wt%), 3.5 wt%. Diantimony trioxide and 1.0% by weight of carbon black. When the obtained test piece was evaluated, it was found from the combustion results that the flammability was insufficient and there was a drop burning phenomenon, and the UL-94V-O burning test could not be passed.

[0059]

[Table 1]

Continuation of front page (56) Reference JP-A-63-135442 (JP, A) JP-A-5-311030 (JP, A) JP-A-6-192513 (JP, A) JP-A-7-97525 (JP , A) JP 7-258507 (JP, A) JP 8-3398 (JP, A) JP 10-147692 (JP, A) JP 2000-44767 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) C08L 51/04 C08K 3/22 C08K 5/00

Claims (5)

(57) [Claims] 1. A rubber-modified styrenic resin (A),
A flame-retardant styrene resin composition comprising (B) a brominated flame retardant and (C) an oxide containing antimony,
In the tetrahydrofuran-soluble component of (A), a molecular weight of 2,000-5
The ratio X (% by weight) of those in the range of 0,000 is 25% by weight or less, and the ratio X and the ratio Y (% by weight) of those having a molecular weight of 1,000,000 or more satisfy X / Y ^1.5 ≤ 10.5, and Bromine content (as bromine atoms) is 8.5 wt% or more, antimony content (as antimony atoms) is 1.0
~ 4.0 wt% flame-retardant styrene resin composition. 2. The flame-retardant styrene resin composition according to claim 1, wherein the ratio X is 23% by weight or less, and the ratios X and Y satisfy X / Y ^1.5 ≦ 10.0. 3. The flame-retardant styrenic resin composition according to claim 1, wherein the content of antimony is 1.5 to 3.5% by weight. 4. (A) contains a graft copolymer obtained by graft-polymerizing an aromatic vinyl monomer and another monomer copolymerizable with the aromatic vinyl monomer in the presence of a rubber-like polymer. Item 5. The flame-retardant styrene resin composition according to any one of items 1 to 3. 5. The rubbery polymer is butadiene rubber, styrene-butadiene rubber, isoprene rubber and ethylene-
The flame-retardant styrene resin composition according to claim 4, which is a diene rubber selected from propylene-diene rubber.