JPH0645739B2 - Flame-retardant ABS resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant ABS resin composition having excellent flame-retardant performance.

(Prior Art) In the field of housing materials for office equipment, demand for flame retardancy has been increasing in recent years. In particular, there is the Electrical Appliance and Material Control Law as a safety standard for electrical materials, and flammability tests are stipulated in the detailed rules for plastic materials. In the United States, UL standards (standards regarding flame retardancy of plastics for electrical equipment) have been established, and highly flame-retardant housing materials are required for products exported to the United States. Even for domestic products, the flame-retardant regulation tends to be strengthened under the influence of the UL standard in the United States. Under such circumstances, there is a strong demand for a flame-retardant housing material.

Examples of the flame-retardant housing material include Noryl (modified PPO). Noryl has excellent mechanical strength, impact resistance, heat resistance, etc., but is expensive and has poor fluidity during molding. In recent years, ABS resin has been used as a housing material in place of Noryl. ABS resin is
It has an excellent total balance of physical properties, is inexpensive, and is easy to mold. However, since ABS resin easily burns, it is necessary to add a flame retardant to make it flame-retardant. As the flame retardant, a vinyl chloride polymer or a low molecular weight halogen compound is generally used. As an ABS resin to which such a halogen-based flame retardant is added, for example, JP-A-54-40
No. 845 discloses chlorinated polyethylene (chlorination degree of 25-
45%), tetrabromobisphenol A and antimony trichloride added compositions are disclosed. JP-A-5
JP-A-4-43255 discloses a composition obtained by adding polyvinyl chloride and antimony trioxide, or polyvinyl chloride and antimony pentoxide to an ABS resin. However, as described above, the ABS resin flame-retarded with the halogen-based flame retardant generates hydrogen halide gas due to thermal decomposition of the halogen compound during molding.
Hydrogen halide gas is toxic to the human body. Discoloration of material,
It also causes the inclusion of carbides and corrosion of the screw and molding die. If the molding temperature is lowered in order to prevent decomposition of the halogen compound, the fluidity of the resin will deteriorate.
Further, the heat distortion temperature of the ABS resin containing polyvinyl chloride is remarkably lowered.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a flame-retardant ABS resin composition in which a flame-retardant agent is not thermally decomposed during molding. To provide things. Another object of the present invention is to provide a flame-retardant ABS resin composition having excellent flame-retardant performance.

(Means for Solving Problems) The flame-retardant ABS resin composition of the present invention comprises 100 parts by weight of an ABS resin having at least a paramethylstyrene unit, 5 to 30 parts by weight of red phosphorus, and 5 to 30 parts by weight of melamine. And 3 to 30 parts by weight of a heat-crosslinking curable resin, whereby the above object is achieved.

The ABS resin having at least paramethylstyrene unit includes, for example, a composition in which at least one styrene monomer unit in the polymer chain of ABS resin is replaced with paramethylstyrene, ABS resin and paramethylstyrene homopolymer. And a polymer blend of an ABS resin and a copolymer containing at least paramethylstyrene.

Here, ABS resin is acrylonitrile, butadiene,
A copolymer resin containing styrene as a main component and a polymer blend thereof. The ABS resin is a blend type of a styrene-acrylonitrile copolymer and an acrylonitrile-butadiene copolymer rubber, and a graft type obtained by graft-copolymerizing styrene and acrylonitrile in the coexistence of a butadiene rubber latex or a styrene-butadiene rubber latex. There is. To improve heat resistance and fluidity of the ABS resin, styrene may be replaced with α-methylstyrene, or a monomer copolymerizable with styrene and acrylonitrile, such as methyl methacrylate, N-, may be used. Phenylmaleinimide may be introduced. It is also preferable to blend other resin components such as polycarbonate.

When the ABS resin having the para-methylstyrene unit is heated, the para-methyl group becomes a methyl radical. Methyl radicals undergo radical coupling to form a crosslinked body. The crosslinked body is effective in preventing dripping of molten plastic when the resin is burned.

The paramethylstyrene unit is 5 in ABS resin.
It is contained in the range of 60 to 60% by weight, preferably 10 to 50% by weight. Below 5% by weight, the effect of preventing drip cannot be obtained. When it exceeds 60% by weight, the characteristics of the ABS resin are adversely affected.

Red phosphorus is a flame retardant for forming a solid film on the combustion surface during the combustion of ABS resin, thereby cutting off the supply of oxygen from the outside.

Generally, a phosphorus compound transforms metaphosphoric acid into polyphosphoric acid during its combustion. Polyphosphoric acid forms a solid film on the combustion surface, which interrupts the supply of oxygen from the outside. In addition, metaphosphoric acid exhibits a dehydrating action in the process of becoming polyphosphoric acid. Therefore, carbonization of the organic compound is promoted. This carbonized layer is also effective in blocking oxygen. Moreover, it is effective in preventing drip.

Surface-treated red phosphorus particles are used for red phosphorus. The surface treatment is carried out by coating the surface of the red phosphorus fine particles with a thermosetting resin as disclosed in JP-A-51-105996 and JP-A-52-125489. By such surface treatment, alteration of red phosphorus fine particles due to moisture in the air is prevented, and danger in handling is also avoided. Red phosphorus particles are ABS resin 10
It is contained in an amount of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 0 parts by weight. If the amount is less than 5 parts by weight, the desired flame retardant performance cannot be obtained. If it exceeds 30 parts by weight, the flame retardant performance is rather deteriorated and the characteristics of the ABS resin are adversely affected.

Melamine is a flame retardant for condensing oxygen near the combustion temperature of the ABS resin and taking a carbonized structure to cut off the supply of oxygen and prevent drip. The amino group in the melamine molecule traps free radicals during the oxidation reaction of the flammable gas to further promote flame retardation. Melamine is contained in an amount of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the ABS resin. If the amount is less than 5 parts by weight, the desired flame retardant performance cannot be obtained. If it exceeds 30 parts by weight, the flame retardant performance is rather deteriorated and the characteristics of the ABS resin are adversely affected.

The heat-crosslinking curable resin is
Resole type phenolic resin and polyacrylonitrile having a reactive methylol group which can be hardened by thermal crosslinking and have a carbonized structure. Due to this carbonized structure, the supply of oxygen is cut off and the ABS resin is made flame-retardant. The carbonized structure also helps prevent drip.

As the resol-based phenol resin, a heat infusible or heat fusible granular phenol resin is used. The phenolic resin of the present invention further has a reactive methylol group. The content of methylol group is 3 to 15% by weight, preferably 5
~ 10% by weight. Moreover, the three-dimensional crosslink density is small.
Therefore, the compatibility between the phenol resin and the ABS resin is improved. Further, when the ABS resin is burned, the condensation of the phenol resin is promoted and the carbonized structure is easily obtained.

Polyacrylonitrile can be obtained by a known polymerization method such as suspension polymerization or emulsion polymerization. The molecular weight is preferably 50,000 to 200,000. Polyacrylonitrile takes on a one-dimensional graphite structure by being cyclized by the heat of combustion. In addition, they condense between each graphite chain and form a graphite skeleton. The graphite skeleton cuts off the supply of oxygen and makes the ABS resin flame-retardant. Instead of polyacrylonitrile, an acrylonitrile copolymer containing 10% by weight or less of a monomer copolymerizable with acrylonitrile may be used.

Such a heat-crosslinking curable resin is contained in an amount of 3 to 30 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the ABS resin. If it is less than 3 parts by weight, the desired flame retardant performance cannot be obtained. If it exceeds 30 parts by weight, the flame retardant performance is rather deteriorated and the characteristics of the ABS resin are adversely affected.

The addition of such a flame retardant effectively makes the ABS resin composition of the present invention flame retardant. A composition obtained by adding a similar flame retardant to a resin other than the ABS resin is disclosed in, for example, Japanese Patent Publication No. 51-27461, but it is desired to apply the composition to the ABS resin as it is. Flame retardant performance cannot be obtained. As shown in the present invention, it is necessary to mix the flame retardant within a certain range.

(Examples) The present invention will be described below with reference to Examples.

Example 1 100 parts by weight of a blend type ABS resin (heat distortion temperature of 90 ° C.) containing 20% by weight of paramethylstyrene unit, red phosphorus fine particles (Nova Red “120, phosphorus) surface-treated with a thermosetting resin Chemical Industry Co., Ltd.) 10 parts by weight, powdered melamine 10 parts by weight and reactive methylol group-containing phenolic resin (Bellpearl S-970, manufactured by Kanebo Co., Ltd.) 10 parts by weight, and mixed at 180-185 ° C. for 0.5 Roll kneading was performed for an hour, and the kneaded material was heated and pressed at 190 to 200 ° C to obtain a thickness of 1.6 mm (1/16
I got a sheet of inch). A test piece with a width of 12.7 mm was cut out from this sheet and a flame-retardant test was performed according to the standards of US UL-94. The results are shown in Table 1.

Example 2 A test piece was prepared in the same manner as in Example 1 except that 20 parts by weight of melamine and 5 parts by weight of phenol resin were used, and the same burning test was performed. The results are shown in Table 1.

Example 3 A test piece was prepared in the same manner as in Example 1 except that 30 parts by weight of melamine and 5 parts by weight of phenol resin were used, and the same burning test was performed. The results are shown in Table 1.

Example 4 A test piece was prepared in the same manner as in Example 1 except that 15 parts by weight of red phosphorus fine particles, 20 parts by weight of melamine, and 5 parts by weight of phenol resin were used, and the same burning test was performed. The results are shown in Table 1.

Example 5 A test piece was prepared in the same manner as in Example 1 except that 20 parts by weight of red phosphorus fine particles and 5 parts by weight of phenol resin were used.
The same combustion test was performed. The results are shown in Table 1.

Example 6 15 parts by weight of red phosphorus fine particles and 20 parts by weight of melamine,
A test piece was prepared in the same manner as in Example 1 except that 5 parts by weight of the phenol resin (Belpearl S-930) was used instead of 10 parts by weight of the phenol resin (Belpearl S-970), and the same burning test was performed. It was The results are shown in Table 1.

Example 7 15 parts by weight of red phosphorus fine particles, 20 parts by weight of melamine, and 5 parts by weight of polyacrylonitrile (Toughtic B, manufactured by Nippon Exlan Co., Ltd.) were used instead of 10 parts by weight of a phenol resin (Bellpearl S-970). A test piece was prepared in the same manner as in Example 1 except for the above, and the same combustion test was performed. The results are shown in Table 1.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1 except that the red phosphorus fine particles were 3 parts by weight and the phenol resin was 5 parts by weight.
The same combustion test was performed. The results are shown in Table 1.

Comparative Example 2 A test piece was prepared in the same manner as in Example 1 except that 35 parts by weight of red phosphorus fine particles and 5 parts by weight of phenol resin were used.
The same combustion test was performed. The results are shown in Table 1.

Comparative Example 3 20 parts by weight of melamine and 5 parts by weight of phenol resin,
A test piece was prepared in the same manner as in Example 1 except that the red phosphorus fine particles were not used, and the same burning test was performed. The results are shown in Table 1.

Comparative Example 4 A test piece was prepared in the same manner as in Example 1 except that 20 parts by weight of melamine was used, 5 parts by weight of polyacrylonitrile was used in place of the phenol resin, and red phosphorus fine particles were not used, and the same combustion test was performed. I went. The results are shown in Table 1.

Example 8 Graft type AB containing 35% by weight of paramethylstyrene units instead of blend type ABS resin containing 20% by weight of paramethylstyrene units (heat distortion temperature 90 ° C.)
A test piece was prepared in the same manner as in Example 1 except that the S-based resin (heat distortion temperature 95 ° C.) was used, and the same combustion test was performed. The results are shown in Table 2.

Example 9 A test piece was prepared in the same manner as in Example 8 except that 20 parts by weight of melamine was used, and the same burning test was performed. The results are shown in Table 2.

Example 10 A test piece was prepared in the same manner as in Example 8 except that 15 parts by weight of red phosphorus fine particles, 20 parts by weight of melamine, and 5 parts by weight of phenol resin were used, and the same burning test was performed. The results are shown in Table 2.

Example 11 A test piece was prepared in the same manner as in Example 8 except that 20 parts by weight of red phosphorus fine particles and 5 parts by weight of phenol resin were used.
The same combustion test was performed. The results are shown in Table 2.

Comparative Example 5 A test piece was prepared in the same manner as in Example 8 except that 3 parts by weight of red phosphorus fine particles and 5 parts by weight of phenol resin were used.
The same combustion test was performed. The results are shown in Table 2.

Comparative Example 6 A test piece was prepared in the same manner as in Example 8 except that 35 parts by weight of red phosphorus fine particles and 5 parts by weight of phenol resin were used.
The same combustion test was performed. The results are shown in Table 2.

Comparative Example 7 Instead of a blend type ABS resin containing 20% by weight of paramethylstyrene unit (heat distortion temperature of 90 ° C.), an ABS resin containing no paramethylstyrene unit (heat distortion temperature of 95 ° C.).
C., EX-450, manufactured by Ube Saikon Co., Ltd.), a test piece was prepared in the same manner as in Example 1 except that the red phosphorus fine particles were 3 parts by weight and the phenol resin was 5 parts by weight. I went. The results are shown in Table 2.

Comparative Example 8 A test piece was prepared in the same manner as in Comparative Example 7 except that the amount of red phosphorus fine particles was 35 parts by weight, and the same burning test was performed. The results are shown in Table 2.

Comparative Example 9 A test piece was prepared in the same manner as in Comparative Example 7 except that 10 parts by weight of red phosphorus fine particles and 30 parts by weight of melamine were used, and no phenol resin was used, and the same burning test was performed. The results are shown in Table 2.

As is clear from Table 1 and Table 2, red phosphorus fine particles 10 to 20 parts by weight, melamine 10 to 10 parts by weight per 100 parts by weight of ABS resin containing 20% by weight of paramethylstyrene unit.
By blending 30 parts by weight and 5 to 10 parts by weight of a heat-crosslinking curable resin, excellent flame retardant performance of UL-94 standard V-0 to V-1 was obtained. Red phosphorus fine particles 10 to 20 parts by weight, melamine 10 to 20 parts by weight and heat-crosslinking curable resin 5 to 10 parts by weight, even with respect to 100 parts by weight of ABS resin containing 35% by weight of paramethylstyrene unit. By blending
Similarly, UL-94 standard V-0 ~ V-1 flame retardant performance. Considering other experimental data by the present inventor, the composition of the present invention contains 5 to 30 red phosphorus fine particles per 100 parts by weight of ABS resin having at least paramethylstyrene unit.
It has been revealed that the desired excellent flame retardant performance can be obtained when the amount of melamine is 5 to 30 parts by weight and the heat-crosslinkable curable resin is in the range of 3 to 30 parts by weight.

As shown in Comparative Examples 3 to 4 and Comparative Example 9, even if any one of these additives is lacking, remarkably low flame retardant performance such as UL-94 standard notV can be obtained. In addition, Comparative Example 1
.About.2 and Comparative Examples 5 to 8, the flame retardant performance is deteriorated even when the amount of the additive deviates from the above range. Also,
When an ABS resin containing no paramethylstyrene unit is used, not only the flame retardant performance is inferior, but also drip is likely to occur.

(Effects of the Invention) Since the flame-retardant ABS resin composition of the present invention thus uses the flame retardant other than the halogen compound, the flame retardant is not thermally decomposed during molding. As a result, generation of toxic gas, discoloration of material, mixing of carbide, corrosion of screw and molding die does not occur. Therefore, the composition of the present invention is useful as a flame retardant material.

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Claims (6)

[Claims] 1. 100 parts by weight of ABS resin having at least paramethylstyrene unit, 5 to 30 parts by weight of red phosphorus,
Thermo-crosslinking curable resin 3 which is at least one of a resole phenolic resin having 5 to 30 parts by weight of melamine and a reactive methylol group and polyacrylonitrile.
A flame-retardant ABS resin composition containing 30 to 30 parts by weight. 2. The ABS resin according to claim 1, wherein at least one styrene monomer unit in the polymer chain of the ABS resin is replaced with paramethylstyrene.
A flame-retardant ABS resin composition according to item. 3. The flame-retardant ABS resin composition according to claim 1, wherein the ABS resin is a polymer blend of an ABS resin and a paramethylstyrene homopolymer. 4. The flame-retardant ABS resin composition according to claim 1, wherein the ABS resin is a polymer blend of an ABS resin and a copolymer containing at least paramethylstyrene. 5. The flame-retardant ABS resin composition according to claim 1, wherein the ABS resin contains a paramethylstyrene unit in a range of 5 to 60% by weight. 6. The flame-retardant ABS resin composition according to claim 1, wherein the red phosphorus is red phosphorus fine particles surface-treated with a thermosetting resin.