JPH01278547A - Antistatic styrene resin composition - Google Patents

Abstract

PURPOSE:To provide the title composition of permanent antistatic nature, outstanding in flame retardancy, thermal properties, mechanical strength and processability, colorable in any color tone, comprising a styrene resin, (a) flame retardant and calcium sulfate. CONSTITUTION:The objective composition can be obtained by kneading in a molten state using e.g., a vent-type single (twin) screw extruder, of a composition comprising (A) 100pts.wt. of a styrene resin (e.g., ABS resin, AS resin), (B) 1-50pts.wt. of at least line kind of flame retardant selected from tetrabromobisphenol A, decabromodiphenyl oxide, triphenylphosphate and antimony trioxide, and (C) 1-30pts.wt. of calcium sulfate 1-50mum in particle size, containing crystal water in the structure or capable of intake of crystal water with time, also invariant in its weight at <=180 deg.C (pref., gypsum hemihydrate or III-type anhydrous gypsum).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a styrenic resin composition having excellent flame retardancy and antistatic properties.

(Prior art and problems) In general, plastics have a high electrical resistance, easily become charged due to friction or contact, attract dirt and dust, and cause problems such as spoiling the appearance of molded objects, sheets, films, and fibers. This causes various problems in various fields. In order to improve this drawback, false color methods have been proposed and put into practical use.

For example, there is a method of kneading or spraying an antistatic agent into a thermoplastic resin. The former method of heating and kneading is simple, but if the antistatic agent present on the surface is removed by washing with water, friction, or other means, the antistatic property will be lost, but the antistatic agent contained inside the molded product will still be removed. However, some parts of the surface are covered with brie 1' to compensate for this. Especially ABS resin, old PS
With styrene-based resins such as resins, there is a problem in that the antistatic agent is difficult to float from the inside to the surface. Furthermore, in thermoplastic resin systems containing flame retardants, the effect of adding antistatic agents was poor and could not be used practically. The latter method of spraying an antistatic agent is very simple, but it has the disadvantage that antistatic properties are more likely to be lost than the former, so εJ is not suitable for applications that require a long-lasting antistatic effect. do not have.

In addition, a method of kneading conductive inorganic materials such as carbon fiber or carbon black into thermoplastic resin has been put into practical use, but although it has a long-lasting antistatic effect, the color tone is limited to black, and carbon There was a problem in that the flame retardancy was improved due to the combination, but the flame retardant level was lowered.

Furthermore, as a method for chemically modifying thermoplastic resins, there is a method of copolymerizing monomers containing polyalkylene oxite groups that have antistatic properties (Japanese Patent Laid-Open No. 58-98317
), there was a problem in that the resin obtained in this case had insufficient antistatic properties under low humidity conditions.

(Another means to solve the problem) The present inventor has discovered that the antistatic effect does not decrease due to washing etc.
In addition, the present invention was achieved as a result of intensive efforts to obtain a resin that can be colored in any color tone and has permanent antistatic properties that do not reduce the flame retardant level.

That is, the present invention provides an antistatic styrenic resin composition with excellent flame retardancy, characterized by comprising 100 parts by weight of a styrene resin, 1 to 50 parts by weight of a flame retardant, and 1 to 30 parts by weight of calcium sulfate. It provides:

The antistatic styrenic resin composition of the present invention will be explained in detail below.

As the styrenic resin used in the present invention, at least one monomer selected from the respective groups of styrene monomers and other vinyl monomers copolymerizable with the monomers, and The term refers to products obtained by polymerization in the presence of rubber-like substances if necessary. Among these, styrenic monomers are styrene, α-methylstyrene, and hydrogen atoms of Hensen's nucleus. is a general term for styrene derivatives substituted with a halogen atom or a C8 to C4 alkyl group, and representative examples of such styrene monomers include styrene, 0-
Examples include chlorstyrene, p-chlorostyrene, p-methylstyrene, 2,4-dimethylstyrene, and t-butylstyrene.

In addition, typical examples of the other copolymerizable vinyl monomers mentioned above include (meth)acrylic I: ni-IJ, α-
Acrylonitrile monomers such as chloroacrylonitrile or vinylidene cyanide; (meth)acrylic acid;
Such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, glycidyl (meth)acrylate, 2-ethylhexyl (meth)acrylate or β-hydroxyethyl (meth)acrylate ( meth)acrylic acid and their various esters; or vinyl acetate, vinyl chloride, vinylidene chloride, vinylpyrrolidone, (meth)acrylamide, dimethyl(
Examples include meth)acrylamide, maleic anhydride, itaconic anhydride, or maleimide, vinyl gels, vinyl ethers, and the like.

Furthermore, typical rubber-like substances mentioned above include polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-butadiene, styrene block copolymer rubber, ethylene-propylene terpolymer rubber, and butadiene-acrylic one-helical copolymer rubber. Rubber, butyl rubber, acrylic rubber, styrene/isobutylene/butadiene copolymer rubber, or isoprene/acrylic acid ester copolymer rubber, which is obtained using a conjugated 1,3-shiconine monomer such as isoprene or chloroprene. There are many types of rubber, but these can be used alone or in combination of two or more types.

One type or combination of two or more of the styrenic resins obtained above, and other resins such as polycarbonate
, polybutylene terephthalate, a combination with polyphenylene ether resin, etc. can be used.

Flame retardants used in the present invention include tetrabromobisphenol A, decabromodiphenyl oxide, octabromodiphenyl oxide, bis(tribromophenoxy)ethane, perchloropentacyclododecane, triphenylbosphate, and tricresyl phosphate. , 1 to butyl phosphate, tris(β-chloroethyl) phosphate, chlorinated polyethylene, antimony trioxide, zinc borate, etc., and one type or a combination of two or more of these can be used.

The amount and combination of flame retardants used can be selected as appropriate depending on the flame retardant level required for the composition, but the amount of flame retardant added depends on mechanical strength, thermal properties, processability, and product cost. The amount is 1 to 50 parts by weight of the flame retardant per 100 parts by weight of the resin, and if it is less than 1 part by weight, the flame retardant effect will be low, and if it is more than 50 parts by weight, the mechanical strength will be greatly reduced, which is not preferred.

Calcium sulfate used in the present invention has the general formula CaSO4
Alternatively, calcium sulfate, which is a gypsum compound represented by Ca5Oa.nH2O and has a particle size of 1 to 50 μmφ, can be used, but usually exhibits the form of fine particles with an average particle size of 15 μmφ. In particular, from the viewpoint of processability and antistatic properties of the composition, gypsum hemihydrate (CaS04.1/21hO) or type anhydrite (IIIcasO4) is preferable.

The amount of calcium sulfate to be used can be appropriately selected depending on the mechanical strength, thermal properties, antistatic properties, and processability of the composition, and is 1 to 30 parts by weight per 100 parts by weight of styrenic resin. If it is less than 1 part by weight, the antistatic properties will be significantly inferior, and if it exceeds 30 parts by weight, the mechanical strength, thermal properties, and processability will be significantly inferior.

In the present invention, calcium sulfate, which contains water of crystallization in its structure or incorporates water of crystallization over time, is an essential component, and calcium sulfate, which is completely anhydrous, cannot be used in the compositions of the present invention. I can't.

The antistatic styrenic resin composition of the present invention is prepared by mixing 100 parts by weight of a styrene resin, 1 to 50 parts by weight of a flame retardant, and 1 to 30 parts by weight of calcium sulfate using a general kneading machine such as a vent type shaft extruder. It is obtained by melt-kneading using a bent-type twin-screw extruder or the like.

There are no restrictions on the shape of the styrene resin used, and any shape such as powder, beads, pellets, dice, etc. can be used.

Furthermore, there are no restrictions on the order of kneading the styrene resin, flame retardant, and calcium sulfate during kneading.

In addition, it is also possible to appropriately blend colorants, antioxidants, ultraviolet absorbers, fillers, etc. into the composition of the present invention.

(Example) The present invention will be explained below with reference to Examples, but the present invention is not limited thereto in any way.

Example-1 AS resin, ABS resin, flame retardant, calcium sulfate, antioxidant, and lubricant were melt-kneaded using an Osaka Seiki pent-type screw extruder (extrusion temperature 180 to 220°C) to form compositions 1 to 5.
I got it.

Compositions 6 to 9 were evaluated as comparative examples, and an antistatic agent was added to compositions 6 to 9.

The obtained composition was molded using a Nissei Plastics FN-1ON injection molding machine (
Various test pieces were prepared at an injection temperature of 200°C) and subjected to evaluation.

The composition and evaluation results of the composition are shown in Table-1.

*Beaded AS resin consisting of 25% by weight of AS resin acrylonitrile and 75% by weight of styrene *ABS resin powdered AB consisting of 25% by weight of acrylonitrile, 40% by weight of butadiene rubber, and 35% by weight of styrene
S resin *Flame retardant tetrabromo bisphenol A, decabromodiphenyl oxide, octabromodiphenyl oxide,
Bis(tribromophenoxy)ethane, chlorinated polyethylene, antimony trioxide * Calcium sulfate hemihydrate gypsum (CaSO4・1/2H20) Average particle size 15 μm ■ Type anhydrite CI [lCa5O4) Average particle size 15 μm * Antioxidant phosphite Antioxidant (diarylmonoalkyl phosphite) *Antistatic fatty acid amide derivative (N,N'-ethylene bisstearamide) *Antistatic agent Miyoshi Dasper 125B Kao Electros I-Ripper-PC, Electro Stripper S 1500 Example-2 ABS resin, heat-resistant ABS resin, ABS resin, AAS resin, PC/ABS resin, flame retardant, calcium sulfate,
The antioxidant and lubricant were melt-kneaded using a Hen I-type screw extruder manufactured by Osaka Seiki Co., Ltd. (extrusion temperature 180-240°C) to obtain compositions 10-18.

In addition, compositions 15 to 18 were evaluated as comparative examples, and compositions 15 to 18 were evaluated.
An antistatic agent was added to samples 1 to 18.

The obtained composition was molded by FN=1ON injection molding R (
Various test pieces were prepared at an injection temperature of 200 to 240°C) and subjected to evaluation.

The composition and evaluation results of the composition are shown in Table-2.

*A +33 Resin acrylonitrile 30% by weight, sitadiene type Goj, 15
Pellet-like ABS consisting of 55% by weight of styrene
Resin *Heat-resistant ABS resin Acryloni I/Tsuru 26% by weight, butadiene rubber 10%
24% by weight, 24% by weight of styrene, 40% by weight of α-me f-lusunarene, 24% by weight of +-shaped heat-resistant ABS resin R3 resin * Pellet-like ABS resin consisting of AAS resin Acrylic 1 to Ryl 25% by weight, acrylic ester comb 10%, and styrene 65% by weight] 2 *PC/ABS resin polymerization degree 22000 Bere/1-shaped ABS resin consisting of 60% by weight of PC resin, 26% by weight of acrylonitrile, 15% by weight of butadiene rubber, and 61% by weight of styrene,
Pellet-shaped PC/ABS resin extruded with 0% by weight blend *@Flame agent decabromodiphenyl oxite, antimony trioxide *Calcium sulfate hemihydrate gypsum (CaSO4・1/21120) Average particle size 15 μm ■ Type anhydrite (ICaSOJ average Particle size 15 IJm *Antioxidant Phosphite antioxidant (searyl mono-alkyl phosphor l-) *Lubricant Fatty acid amide derivative (N,N'-ethylene bisstearamide) *Antistatic agent Miyoshi Yushi Co., Ltd. Dust Bar] 25B (Effects of the Invention) The antistatic styrenic resin composition of the present invention naturally does not reduce its antistatic effect due to washing, friction, etc.
It is a material that can be colored in any color, maintains a sufficient degree of flame retardancy, and has excellent thermal properties, mechanical strength, and processability.

Therefore, if used as housing materials and structural component materials for OA equipment, office equipment, various home appliances, general miscellaneous goods, etc., it will prevent dust and debris from adhering and accumulating while products are being stored and displayed. This not only improves the product image, but also frees office automation equipment and office equipment from troubles caused by static electricity in the vapor guide mechanism.

Claims (1)

[Scope of Claims] 1) An antistatic styrenic resin composition comprising 100 parts by weight of a styrene resin, 1 to 50 parts by weight of a flame retardant, and 1 to 30 parts by weight of calcium sulfate. 2) Flame retardants include tetrabromobisphenol A, decabromodiphenyl oxide, octabromodiphenyl oxide, bis(tribromophenoxy)ethane, perchloropentacyclododecane, triphenyl phosphate, tricresyl phosphate, tributyl phosphate, tris( The antistatic styrenic resin composition according to claim 1, which contains one or a combination of two or more of β-chloroethyl) phosphate, chlorinated polyethylene, antimony trioxide, and zinc borate. 3) Calcium sulfate contains water of crystallization in its structure or has the ability to incorporate water of crystallization over time, and is heated to 180°C.
The antistatic styrenic resin composition according to claim 1 or 2, characterized in that there is no weight change at the following temperatures, and the antistatic styrenic resin composition has a granular form of 1 to 50 μmφ.