JPH11116748A - Preparation of self-extinguishing styrene-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the preparation of a self-extinguishing styrene-based resin composition exhibiting well-balanced mechanical properties even after being endowed with a self-extinguishing function. SOLUTION: Hundred pts.wt. of a mixed resin (A) of (A1) with (A2), 1-50 pts.wt. of a halogen-containing flame retarder (B) and 0-30 pts.wt. of a flame retarder aid (C) are compounded and kneaded by means of an extruder, where (A1) is a rubber-modified styrene-based resin having a rubbery polymer content of 3-20 wt.%, a wt. average particle size of the dispersed rubber particles of 0.4-1.0 μm, a proportion of particles having salami structure in the dispersed rubber particles of 80% or more and a ratio of a toluene insoluble content (wt.%) to the rubbery polymer content (wt.%) of 2.4 or less, and (A2) is a rubber-modified styrene-based resin having a rubbery polymer content of 3-20 wt.%, a wt. average particle size of the dispersed rubber particles of 1.1-5.0 μm and a ratio of a toluene insoluble content (wt.%) to the rubbery polymer content (wt.%) of 2-4. A bromine-containing flame retarder having a melting or softening point of 200 deg.C or above is preferably applicable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a self-extinguishing styrenic resin composition, and more particularly, to U.S. Underright Laboratory Inc. (hereinafter "U").
L "), which is a self-extinguishing styrenic material having a high balance of mechanical properties such as high impact resistance, rigidity, moldability, etc., which satisfies UL Standard No. 94 of the self-extinguishing standard (hereinafter," UL-94 standard ") The present invention relates to a method for producing a resin composition.

[0002]

2. Description of the Related Art A self-extinguishing resin composition comprising a styrenic resin, a halogen-based flame retardant and a flame retardant auxiliary has high self-extinguishing properties at a low cost, as well as heat resistance, impact resistance, and the like. Because of their excellent rigidity, moldability, dimensional stability, electrical insulation, etc., they are used in various fields including home electric appliance parts, OA equipment parts, and automobile parts.

However, recently, as these parts have become thinner, lighter, more complex, and larger, the demand for a composition comprising a styrene-based resin, a halogen-based flame retardant, and a flame-retardant auxiliary has been increasing. It has been difficult for conventional compositions comprising a styrene-based resin, a halogen-based flame retardant, and a flame-retardant auxiliary (for example, JP-A-54-68854) to satisfy the requirements. In particular, from the field of home electric appliances and the like, there is an increasing demand for enhancing the impact resistance of a self-extinguishing styrene-based resin so that sufficient strength can be maintained even when the thickness is reduced. It is an important issue. In particular, in the self-extinguishing of styrenic resins using bromine-based flame retardants among the halogen-based flame retardants, the impact resistance after imparting the self-extinguishing function tends to decrease. There was a need to improve.

[0004] Various proposals have been made in order to satisfy such demands. For example, JP-A-7-102137 and JP-A-8-199023 disclose a self-extinguishing polystyrene composition having high impact resistance using a halogen-containing compound having a specific structure as a flame retardant. However, these technologies are technologies that achieve high impact strength after self-extinguishing by using a flame retardant with a specific structure. It is not a technology that guarantees the use of flame retardants.

[0005] One technique for developing a high impact strength of a self-extinguishing resin composition against the use of a halogen-based flame retardant whose structure is not specified is to increase the impact resistance of a styrene resin composition as a base resin. There have been various proposals for that. For example, Japanese Unexamined Patent Publication (Kokai) No. 3-281649 discloses a flame-retardant resin composition comprising a rubber-modified styrenic polymer, wherein the dispersed rubber particles in the composition consist of two specific peaks of a large particle portion and a small particle portion. It is disclosed that a composition obtained by combining a rubber-modified styrenic polymer having a distribution and a halogen-based flame retardant having a specific range of melting point or softening point exhibits good impact resistance and appearance.

However, the technique disclosed in the above publication mainly focuses on the balance between the appearance of the molded product and the impact resistance, and the maintenance of high impact resistance after imparting the self-extinguishing function is still insufficient. Not a satisfactory technology. In addition, this is a technique in which only the content of the dispersed rubber in the resin composition and the range of the particle diameter are controlled, and does not describe any control of the dispersed rubber form necessary for maintaining the physical property balance,
In addition, the melting point or softening point of the halogen-based flame retardant is 100
~ 200 ° C, when self-extinguishing using a flame retardant with a high softening point 200 ° C or higher, which is known for its versatility,
The level of impact resistance was greatly reduced and was not satisfactory. In particular, when such a flame retardant having a low softening point is used, there is a concern that problems such as a decrease in heat resistance and occurrence of burns at the time of molding are concerned, so that there is also a disadvantage that the applicable range is limited.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide a high impact resistance even after imparting a self-extinguishing function by using an unspecified halogen-based flame retardant.
An object of the present invention is to provide a method for producing a self-extinguishing styrenic resin composition having a balance between rigidity and mechanical properties of moldability.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have determined the amount of the dispersed rubber component, the rubber particle diameter, the ratio of the toluene insoluble content of the rubber to the rubber content, and the like. The inventors have found that the above problems can be solved by uniformly kneading and blending a halogen-based flame retardant and antimony trioxide into a resin obtained by mixing two specified rubber-modified styrene-based resins, and completed the present invention.

That is, the present invention relates to the following (A1) and (A2) wherein the rubbery polymer is dispersed in the form of particles in a matrix composed of an aromatic monovinyl polymer; (RC: weight%) 3 to
20% by weight, the weight average particle diameter of the dispersed rubber particles is 0.4 to
The ratio of the number of rubber particles having a salami structure in dispersed rubber particles having a particle diameter of 1.0 μm or less is not less than 80%, and a toluene-insoluble content (TI: wt%) and a rubber-like polymer content (RC: weight) %), A rubber-modified styrenic resin having a ratio TI / RC of 2.4 or less; (A2); a rubbery polymer content (RC:% by weight) of 3 to
20% by weight, the weight average particle diameter of the dispersed rubber particles is 1.1 to
5.0 μm, the ratio TI / RC of the toluene-insoluble matter (TI: wt%) to the rubbery polymer content (RC: wt%) is 2 to 4
Rubber-modified styrenic resin, Mixed resin (A) 100
1 to 50 parts by weight of a halogen-based flame retardant (B) and 0 to 30 parts by weight of a flame retardant auxiliary (C) based on parts by weight, and melt-kneaded using an extruder. This is a method for producing a resin composition.

In the present invention, in particular, the mixed resin (A)
The total content of the rubbery polymer in the composition is 3 to 20% by weight, and 99 to 30% by weight of the total content of the rubbery polymer is (A1)
Therefore, it is preferable to mix two types of rubber-modified styrene resins so that 1 to 70% by weight is formed from (A2). In the case of (A1) and (A2), the ratio of TI to RC is preferably smaller for the former and larger for the latter to form the mixed resin (A). Further, as the halogen-based flame retardant of the component (B), it is preferable to use a bromine-based flame retardant having a melting point or a softening point of 200 ° C. or more. Furthermore, it is preferable to use antimony trioxide as the flame retardant aid of the component (C).

According to the present invention, two types of rubber-modified styrenic resins (A1) and (A2) having a large particle portion and a small particle portion having different particle diameters of the dispersed rubber-like polymer are produced. To control the content of the dispersed rubber-like polymer, the form of polystyrene encapsulated in the dispersed rubber and the ratio of the rubber-modified styrene-based resin's toluene-insoluble matter to the rubber content to a specific optimum state and then to mix them High impact resistance, even after adding an unspecified halogen-based flame retardant to give a self-extinguishing function,
A self-extinguishing styrene resin composition excellent in rigidity and excellent balance of mechanical properties of moldability can be easily obtained. In particular, even when a flame retardant comprising a versatile high-melting bromine compound having a softening point of 200 ° C. or more is added, a UL-94 standard V0 grade in which the reduction in impact resistance is greatly improved can be easily obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
Two types of rubber-modified styrenic resins (A) used in the present invention
Both 1) and (A2) are polymers in which a rubbery polymer is dispersed in a special particle having a specific structural factor in a matrix composed of an aromatic monovinyl polymer. Such a rubber-modified styrene-based resin is dissolved in the presence of a rubber-like polymer by adding an aromatic monovinyl-based monomer such as styrene and other vinyl-based monomers copolymerizable therewith, if necessary. Known bulk polymerization methods, bulk suspension polymerization methods, solution polymerization methods, emulsion polymerization methods, and the like can be used, each of which is manufactured by individually changing the polymerization conditions.

Here, examples of the aromatic monovinyl monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene and the like. Other vinyl monomers copolymerizable therewith include methyl methacrylate, ethyl methacrylate,
(Meth) acrylates such as methyl acrylate and ethyl acrylate, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile, methacrylic acid, acrylic acid, maleic anhydride, phenylmaleimide, cyclohexylmaleimide or halogen-containing vinyl Monomers. These copolymerizable monomers are as follows:
Only the species may be used, or two or more species may be used in combination.

These other copolymerizable vinyl monomers are used in an amount of preferably 15% by weight or less, particularly preferably 5% by weight or less, based on the total aromatic monovinyl monomer containing styrene. . The most preferred matrix composed of an aromatic monovinyl polymer is composed only of polystyrene, and a homo-polystyrene-based rubber-modified styrene resin usually called high impact polystyrene (HIPS) can be mentioned as an optimum resin.

The rubber-modified styrenic resin of the present invention (A
1) As the rubbery polymer used in the production of (A2),
Polybutadiene, styrene-butadiene copolymer, polyisoprene, butadiene-styrene-polyisoprene copolymer, natural rubber and the like can be used. The microstructure of the polybutadiene portion may be low-cis polybutadiene rubber, high-cis polybutadiene rubber, or a mixture of low-cis polybutadiene rubber and high-cis polybutadiene rubber. The structure of the styrene-butadiene copolymer rubber may be a random type, a block type or a taper type. One of these rubbery polymers can be used alone, or two or more can be used in combination. However, when a styrene-butadiene copolymer is used as the rubber-like polymer, the rubber-modified styrene-based resin as the component (A) of the present invention has a salami structure particularly for the dispersed rubber particles forming the small particle portion. Preferably, the styrene content in the styrene-butadiene copolymer is 10% or less.

The content of the rubbery polymer of the rubber-modified styrenic resins (A1) and (A2) used in the present invention (RC:% by weight, hereinafter simply abbreviated to RC) is 3 to 20% by weight. And preferably in the range of 6 to 16% by weight. If the content is less than 3% by weight, the impact resistance becomes low, which is not preferable. If it exceeds 20% by weight,
The fluidity, rigidity, and surface hardness of the rubber-modified styrene resin are significantly reduced, and the self-extinguishing properties are also unfavorably reduced. However, these rubber-modified styrenic resins (A1),
RC at the time of mixing (A2) may be the same or different.

Further, a rubber-modified styrenic resin (A1),
In order to achieve a high mechanical strength in a well-balanced manner by mixing (A2), it is necessary that the rubber particles dispersed in (A1) and (A2) have different weight average particle diameters. . That is, in the rubber-modified styrene resin (A1),
The rubber weight average particle diameter of the dispersed rubber particles is 0.4 to 1.0.
It is necessary to be in the range of μm, preferably in the range of 0.5 to 1.0 μm, and most preferably in the range of 0.7 to 1.0 μm. 0.4μ weight average particle size
If it is less than m, the impact resistance of the mixed resin (A) is insufficient, and if it exceeds 1.0 μm, it is not preferable from the viewpoint of balance of physical properties such as a decrease in rigidity as compared with an improvement in impact resistance.

In the rubber-modified styrenic resin (A2), the rubber weight average particle diameter of the dispersed rubber particles is 1.1 to 1.1.
It is necessary to be in the range of 5.0 μm, and 1.5 to 4.0
μm, preferably 2.0 to 3.0 μm
Is most preferably within the range. When the weight average particle diameter is less than 1.0 μm, the impact resistance of the mixed resin (A) is insufficient, and when it exceeds 5.0 μm, it is difficult to improve the impact resistance, but the rigidity is reduced. Is not preferred.

Further, a rubber-modified styrenic resin (A1),
In (A2), most of the dispersed rubber particles need to have a salami structure. Here, the dispersed rubber particles having a salami structure include two or more particles of the aromatic vinyl polymer included in the dispersed rubber particles. In particular, it is important that the ratio of the number of rubber particles having a salami structure in the dispersed rubber particles of the small particle portion having a particle diameter of 1.0 μm or less in the rubber-modified styrene resin (A1) is 80% or more. If the ratio of the dispersed particles is less than 80%,
Impact resistance decreases. The aromatic vinyl-based polymer particles included herein are defined as an electron micrograph of a rubber-modified styrene-based resin obtained by an ultra-thin section method, and a photograph obtained by magnifying 10,000 times and having a particle diameter of 0.3 mm ( That is, it means particles having an actual size of 0.03 μm or more. When the particles have an elliptical shape, the average value of the major axis a and the minor axis b (a +
b) / 2 is defined as the particle diameter.

In the present invention, in order to balance impact resistance and rigidity, toluene-insoluble matter (TI: wt%, hereinafter simply abbreviated to TI) due to dispersed rubber particles is used.
And RC must be controlled within a certain range. That is, in the rubber-modified styrenic resin (A1) having the dispersed rubber particles in the small particle portion, the ratio of TI to RC needs to be 2.4 or less, preferably 1.5 to 2.4. Here, if it exceeds 2.4, the rigidity is undesirably reduced. If the lower limit is 1.5 or less, the impact resistance is lowered, which is not preferable. On the other hand, in the rubber-modified styrenic resin (A2) having large particles of dispersed rubber particles, the ratio of TI to RC is 2
It is necessary to be not less than 4 and preferably not less than 2.5 and not more than 3.5. If it is less than 2, the impact resistance is significantly reduced,
If it exceeds 4, the rigidity decreases, which is not preferable. (A
In (1) and (A2), it is preferable that the ratio of TI to RC is smaller than the former and the latter is larger to form a mixed resin (A) from the viewpoint of improving the impact resistance and securing the balance of physical properties such as rigidity.

In the present invention, the rubber-modified styrenic resin (A
When 1) and (A2) are mixed, the total content of the rubbery polymer should be 3 to 3 in order to maintain good balance between impact resistance and other mechanical properties in the mixed resin (A). 20 to 30% by weight in the total content of the rubbery polymer.
Since the weight% has dispersed rubber particles of a small particle portion (A1),
1 to 70% by weight has large particles of dispersed rubber particles (A
It is preferable to appropriately adjust the mixing ratio of the two types of rubber-modified styrenic resins and mix them as formed in 2).
If the content of the small particles is less than 30% by weight and the content of the large particles is more than 70% by weight, the synergistic effect of improving the impact resistance is reduced, and the balance with other mechanical properties is deteriorated. On the other hand, if the content of the small particle portion is more than 99% by weight and the content of the large particle portion is less than 1% by weight, when a flame retardant is blended, impact resistance may not be easily exhibited depending on the flame retardant used.

The method for producing the rubber-modified styrenic resins (A1) and (A2) used in the present invention is not particularly limited, but in particular, the specific structure of the rubbery polymer-dispersed particles of the present invention can be surely obtained. As a preferred method for obtaining it, it is preferable to use a continuous bulk polymerization apparatus in which a complete mixing type reactor and one or more plug flow reactors are arranged in series. In this case, the rubbery polymer is added to an aromatic vinyl-based monomer such as styrene, and a raw material solution containing a solvent, an organic peroxide, a chain transfer agent and other additives is added continuously as necessary. 1 to a complete mixing type reactor, where the rubbery polymer is polymerized to a range where it does not become dispersed particles, and then the polymerization rate is increased in a plug flow type polymerization reactor to make the rubbery polymer into dispersed particles. After further increasing the conversion, the volatile components are removed under reduced pressure.

At this time, the dispersion rubber particle diameter and the salami structure specified in the present invention are adjusted by controlling the degree of polymerization at which the rubbery polymer does not become dispersed particles in the above-mentioned complete mixing type reactor, and the degree of polymerization in the plug flow reactor. This can be achieved by appropriately adjusting the stirring conditions at the time of producing the rubber particles, or partially mixing the polystyrene containing no rubber-like polymer. The ratio of TI to RC specified in the present invention can be adjusted by polymerization conditions such as the type of rubbery polymer used, polymerization temperature, and stirring conditions during the reaction.

The rubber-modified styrenic resin (A1) of the present invention
When (A2) and (A2) are mixed, a styrene resin containing no rubber component can be further contained. The amount of the styrene resin containing no rubber component is 50 parts by weight based on 100 parts by weight of the mixed rubber-modified styrene resin (A).
Not more than parts by weight. The styrene-based resin containing no rubber component may be added at the same time as the halogen-based flame retardant is added, or may be previously contained in the rubber-modified styrene-based resin (A). here,
Preferable examples of the styrene resin containing no rubber component include polystyrene, which is a homopolymer of a styrene monomer. In the present invention, the flowability of the resin composition can be easily adjusted by including the styrene resin containing no rubber component in the component (A).

Next, as the halogen-based flame retardant (B) to be blended in the present invention, a bromine-based flame retardant containing a bromine atom can be preferably used. The type of the flame retardant is not particularly limited, but tris (tribromophenoxy) S triazine, decabromobiphenyl ether, octabromodiphenyl ether, hexabromodiphenyl ether, tris (2,3-dibromopropyl) isocyanurate, Decabromodiphenylethane,
Bistribromophenoxyethane, bis (pentabromophenoxy) ethane, ethylenebistetrabromophthalimide, decabromobiphenyl, brominated polystyrene with 1 to 5 nuclear bromine substitution, poly (dibromophenylene ether), tetrabromobisphenol-A, tetrabromobisphenol -A. Diglycidyl ether, tetrabromobisphenol-A type epoxy oligomer, tetrabromobisphenol-A type polycarbonate oligomer,
Examples include polypentabromobenzyl acrylate and hexabromocyclododecane.

Among these brominated flame retardants, those having a melting point or softening point of 200 ° C. or more are preferred, and those having a melting point of 210 ° C. or more are particularly preferred. When a flame retardant having a melting point or a softening point of 200 ° C. or more is used, a self-extinguishing function is easily provided (particularly, UL-94 standard V-
0 can be easily achieved), and also can realize a higher impact resistance more effectively than the conventional self-extinguishing styrene-based composition, and have a reduced heat resistance when the softening point is 200 ° C. or lower, There is no problem such as burns. The type of the flame retardant is not particularly limited, and examples thereof include decabromodiphenyl ether, decabromodiphenylethane, and ethylenebistetrabromophthalimide. The blending amount of the flame retardant is not particularly limited, and varies depending on the rank of the self-extinguishing property of the UL-94 standard to be achieved.
The amount is usually 1 to 50 parts by weight with respect to 100 parts by weight of the mixed resin (A) of (A2) and (A2), and about 3 to 30 parts by weight is preferable even in view of the balance with mechanical properties.

In order to further enhance the self-extinguishing properties, it is preferable to add (C) a flame retardant aid as a flame retardant aid. The type of the flame retardant aid is not particularly limited, but includes antimony oxides such as antimony trioxide, tin compounds such as tin oxide, molybdenum compounds such as molybdenum oxide, and zinc compounds such as zinc borate. And the like.
Among them, the use of antimony trioxide is preferable because effective self-extinguishing properties and good mechanical properties can be realized at low cost. The amount of the flame-retardant aid is not particularly limited, and varies depending on the rank of the self-extinguishing property of the UL-94 standard to be achieved, but the mixed resin of the above (A1) and (A2) (A) Usually 0 per 100 parts by weight
To 30 parts by weight, and about 0.5 to 20 parts by weight is preferable even in view of balance with mechanical properties.

With respect to 100 parts by weight of the mixed resin (A) of the above (A1) and (A2) of the present invention, (D) styrene-butadiene block copolymer and / or styrene-isoprene block copolymer Incorporation of a coalescence is also preferable from the viewpoint of synergistic improvement of the impact resistance of the composition. The (D) styrene-butadiene block copolymer and / or styrene-isoprene block copolymer has a polybutadiene or polyisoprene content of 60 to 95% by weight and a solution viscosity (25 g / dl toluene solution, (Measured at 25 ° C) is 1200-24000c
ps are preferable, and those having a polybutadiene or polyisoprene content of 70 to 90% by weight and a solution viscosity (a 25 g / dl concentration toluene solution, measured at 25 ° C) of 1500 to 10000 cps are more preferable.

(D) The microstructure of the polybutadiene portion in the block copolymer may be low-cis polybutadiene rubber, high-cis polybutadiene rubber, or low-cis polybutadiene rubber and high-cis polybutadiene rubber. It may be a mixture. The structure of the styrene-butadiene copolymer rubber may be a random type, a block type or a taper type. Further, both the linear type and the side chain type can be used. Specific examples of the block copolymer are preferably a styrene-butadiene diblock copolymer, a styrene-butadiene block copolymer, a styrene-isoprene diblock copolymer, and a styrene-isoprene triblock copolymer. No. When the above (D) block copolymer is added, the amount of (A) component 10
The amount is preferably 0 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, most preferably 0.3 to 5 parts by weight with respect to 0 parts by weight. By adjusting to this range, impact resistance can be improved.

The self-extinguishing styrenic resin composition of the present invention may further comprise (E) a silicone oil, if desired. Examples of such a silicone oil include those having a structure represented by the following general formula (I). (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ represent organic groups such as an alkyl group, a phenyl group, and an aralkyl group.)

The silicone oil used here is 2
The surface tension at 5 ° C. is 19.0 to 22.0 dyne /
cm, preferably 19.8-21.5 dyne / cm,
More preferably, it is desirable to be in the range of 20.1 to 21.2 dyne / cm. The viscosity of the silicone oil is not particularly limited, but is preferably 10 to 1000 cps at 25 ° C. The amount of the silicone oil to be added is as described in (A1) above.
To 100 parts by weight of the mixed resin (A) of (A) and (A2).
001 to 0.5 parts by weight, more preferably 0.1 to 0.5 parts by weight.
002 to 0.3 parts by weight, most preferably 0.005 to
The range is 0.2 parts by weight. By adjusting the addition amount of silicon oil and the surface tension in this range, the impact resistance can be further improved.

Examples of the silicone oil that can be used in the present invention include dimethyl silicone oil, methylphenyl silicone oil, methylethyl silicone oil, or hydroxyl, fluorine, alkoxy groups at the terminals or in the molecular chains of these silicone oils. Examples include silicone oil into which an amino group, an epoxy group, a carboxyl group, a halogen group, an amide group, an ester group, and a vinyl group are introduced. These silicone oils may be used alone or as a mixture of two or more.

The silicone oil of the present invention can be added at any stage. Specific examples of the addition method include, for example, a rubber-modified styrenic resin (A1) or (A2)
A method of adding to a raw material before performing polymerization, a method of adding to a polymerization solution during polymerization, a method of adding in a granulation step after completion of polymerization, a method of adding using a kneader, and the like. . Among these, a method of adding in the polymerization step of the rubber-modified styrenic resin, a method of adding after polymerization is preferable, and the like are preferable. As a method of adding after the polymerization is completed, for example, a master pellet having a high silicon oil concentration is produced using silicone oil and a styrene-based resin or a rubber-modified styrene-based resin, and the master pellet and the rubber-modified styrene-based resin are extruded and molded. A method of mixing with a machine or the like is also preferable.

In the present invention, if necessary, a lubricant may be added to further improve the fluidity while maintaining the mechanical properties and the like of the self-extinguishing styrenic resin composition.
Examples of the lubricant that can be used in the present invention include polyolefin lubricant, metal soap lubricant, fatty acid ester lubricant, alcohol lubricant, fatty acid lubricant, polysiloxane lubricant, aromatic compound oligomer, liquid paraffin, and the like, and mixtures thereof. Can be The amount of the lubricant is usually 10 parts by weight or less, preferably 5 parts by weight, per 100 parts by weight of the component (A).
Not more than parts by weight. If the amount of the lubricant exceeds 10 parts by weight, the inherent properties of the resin are lost, which is not preferable.

If necessary, other thermoplastic resins and thermosetting resins can be added to the styrenic resin composition of the present invention as long as the effects of the present invention are not impaired. Also,
If necessary, ordinary additives, for example, antistatic agents, antioxidants, ultraviolet absorbers, coloring agents, surface modifiers, metal soaps, organotin compounds, light stabilizers, processing aids, foaming agents, glass Inorganic fillers such as fibers and talc can be added.

The method of compounding the rubber-modified styrenic resins (A1) and (A2), the halogen-based flame retardant (B), the flame-retardant aid (C), and other additives in the present invention is described in, for example, a drum tumbler. After mixing uniformly by using a single-screw extruder or a twin-screw extruder, the mixture can be easily manufactured by pelletizing. The self-extinguishing styrenic resin composition of the present invention thus obtained is, for example, injection-molded, extruded or compression-molded,
Various molded articles having excellent balance between moldability and mechanical properties, as well as excellent self-extinguishing properties and coloring properties can be obtained.

[0037]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The examples of the present invention were evaluated based on the following evaluation methods. All percentages and parts in the examples are on a weight basis.

(1) Rubber content (RC:% by weight); determined by the Wies method.

(2) Measurement of toluene-insoluble matter (TI: wt%): 1 g of the rubber-modified styrene resin composition was added to toluene 30
ml, and centrifuged at 14,000 rpm.
After centrifugation at 20 ° C. for 30 minutes, the supernatant is removed and the insoluble matter is separated. After the toluene is removed by drying the insoluble matter, the weight of the insoluble matter is determined and calculated by the following formula. TI (% by weight) = (weight of insoluble matter / weight of resin composition)
× 100

(3) Measurement of rubber particle diameter: The resin is stained with osmium tetroxide, and an electron micrograph is taken by an ultra-thin section method. In a photograph magnified 10000 times, the particle diameter of 1000 or more dispersed rubber particles is measured, and the average particle diameter is determined by the following equation. The average particle diameter ^{_{D w = Σn i D i 4}} ÷ Σn i D i 3 ( where n _i is the number of rubbery polymer particles having a particle diameter D _i)

(4) Confirmation of the ratio of the number of salami-type dispersed rubber particles in the dispersed rubber particles having a rubber particle diameter of 1.0 μm or less; Dispersion rubber particles having a diameter of 10 mm or less (ie, actual size of 1.0 μm) in a photograph magnified 10,000 times. 200 were arbitrarily selected and confirmed. However, the lower limit of the dispersion rubber particles was set to 0.5 mm (ie, the actual size of 0.05 μm) in the photograph.

(5) Izod impact strength (Izod);
It was measured at 23 ° C. by a method according to ASTM D-256 (V notch, １ ／ inch test piece).

(6) Melt flow rate (MFR);
The measurement was carried out under the conditions of a load of 5 kgf and a measurement temperature of 200 ° C. by a method based on IS K-7210.

(7) Flexural modulus; ASTM D-790
It measured at 23 degreeC by the method based on.

(8) Self-extinguishing U
Test for self-extinguishing properties based on L-94 standard
It was performed at 2.1 mm.

Reference Example 1 Preparation of Rubber-Modified Styrenic Resin Having Small Particles of Dispersed Rubber A mixed solution of polybutadiene rubber dissolved in styrene was thermally polymerized, and then the polymer was removed under reduced pressure to remove volatile components. Later it was pelletized. According to the above method, the weight average particle diameter of the dispersed rubber particles is 0.7 μm, and the rubber particle diameter is 1.0
A rubber-modified styrene-based resin was obtained in which 96% of the rubber particles having a salami-type structure were contained in the dispersed rubber particles having a particle size of μm or less. To this, polystyrene not modified with rubber was added to adjust the RC in the rubber-modified styrene resin to 15% by weight.
The ratio of RC was obtained Table 1 rubber-modified styrenic resin A ₁ described in 1.9 (Examples 1 to 5 and Comparative Examples 2, 7, 8,
9, 10). In the same manner, among the dispersed rubber particles having a rubber particle diameter of 1.0 μm or less, the rubber particles having a salami structure are 80% or more, the RC is 15% by weight, and the weight average particle diameter is 0.3 μm to 1. 7 μm, rubber-modified styrene resin A shown in Table 1 having a ratio of TI to RC of 1.8 to 3.0
_I, to give A _II, A _III a (used in Comparative Example 3, 4 and 5). Further, in the same manner, in the dispersed rubber particles having a rubber particle diameter of 1.0 μm or less, the rubber particles having a salami structure are less than 80%, the RC is 15% by weight, the weight average particle diameter is 0.7 μm,
A rubber-modified styrenic resin A _IV (used in Comparative Example 6) shown in Table 1 having a ratio of TI to RC of 1.6 was obtained.

Reference Example 2 Preparation of Rubber-Modified Styrenic Resin Having Large Particles of Dispersed Rubber A mixture of styrene and polybutadiene rubber dissolved therein was thermally polymerized, and then the volatile components were removed from the polymer under reduced pressure. Later it was pelletized. By the method described above, a rubber-modified styrene resin having a weight average particle diameter of the dispersed rubber particles of 2.1 μm and a salami structure was obtained. This polystyrene is not rubber-modified was added to adjust so that the RC in the rubber-modified styrene resin is 9.4 wt%, to obtain a rubber-modified styrenic resin B ₁ in Table 1 (Example 1 5, and Comparative Examples 1, 3, 4, 5, and 6). In the same manner, a table having a salami-type structure, a RC of 9.4% by weight, a weight average particle diameter of 1.0 μm to 6.0 μm, and a ratio of TI to RC of 1.9 to 4.1. The rubber-modified styrenic resins B _I , B _II , B _III , and B _IV described in 1 (used in Comparative Examples 7, 8, 9, and 10) were obtained. Table 1 shows the two types of rubber-modified styrene resins obtained as described above.

[0048]

[Table 1]

[0049] were mixed in a ratio of rubber-modified styrene resin A ₁ 50 parts by weight of B ₁ 50 parts by weight in Example 1. Table 1, with respect to those of the resin 100 parts by weight, decabromodiphenyl ethane (trade name "SA
YTEX 8010 "15 parts by weight of Ethyl Corporation), 5 parts by weight of antimony trioxide, 1 part by weight of a lubricant, 0.1 part by weight of dimethylpolysiloxane having a surface tension of 20.9 dyne / cm, and 2 parts by weight of mineral oil are added and mixed. Cylinder temperature 25 with twin screw extruder with screw diameter 30mm
The mixture was melt-kneaded and pelletized at 0 ° C. The sample was molded at a cylinder temperature of 200 ° C. and a mold temperature of 40 ° C. for evaluation. Table 2 shows the results.

[0050] except that a mixing ratio of the rubber modified styrenic resin A ₁ 75 parts by weight of B ₁ 25 parts by weight in Example 2 in Table 1 was subjected to a same manner as in Example 1. Table 2 shows the results.

[0051] except that a mixing ratio of the rubber modified styrenic resin A ₁ 25 parts by weight of B ₁ 75 parts by weight in Example 3 in Table 1 was subjected to a same manner as in Example 1. Table 2 shows the results.

Example 4 The same operation as in Example 1 was carried out except that decabromodiphenyl ether (trade name “SAYTEX 102E” manufactured by Ethyl Corporation) was used as a brominated flame retardant. Table 2 shows the results.

Example 5 Ethylene bistetrabromophthalimide (trade name "SAYTEX BT-9" manufactured by Ethyl Corporation) was used as a brominated flame retardant.
3)), except that Example 1 was used. Table 2 shows the results.

[0054] was able as in Example 1 except for using only the rubber-modified styrenic resin B ₁ 100 parts by weight in Comparative Example 1 in Table 1.
Table 2 shows the results.

[0055] was able as in Example 1 except for using only the rubber-modified styrenic resin A ₁ 100 parts by weight in Comparative Example 2 in Table 1.
Table 2 shows the results.

[0056]

[Table 2]

From the results in Table 2, it can be seen that the composition using the specific rubber-modified styrenic resin obtained according to the present invention as a molding material, especially when a flame retardant having a melting point of 200 ° C. or higher is used.
MFR as an index of moldability and Iz as an index of impact resistance
It can be seen that an excellent balance between flexural modulus, which is an index of od impact strength and rigidity, and good self-extinguishing properties (V-0). On the other hand, from the results of Comparative Examples 1 and 2, the self-extinguishing property (V-0) was obtained when the dispersed rubber was only the large particle portion or only the small particle portion.
However, the flexural modulus and Izod impact strength are greatly reduced, and the self-extinguishing resin composition excellent in the balance of physical properties is obtained only when the dispersed rubber has a proper ratio of the small particle portion to the large particle portion. Is obtained.

[0058] except that a mixing ratio of the rubber-modified styrene resin A _I 50 parts by weight of B ₁ 50 parts by weight in Comparative Example 3 in Table 1 was subjected to a same manner as in Example 1. Table 3 shows the results. It can be seen that if the weight average particle diameter of the dispersed rubber is too small, sufficient impact resistance is not exhibited.

[0059] except that a mixing ratio of the rubber-modified styrene resin A _II 50 parts by weight of B ₁ 50 parts by weight in Comparative Example 4 in Table 1 was subjected to a same manner as in Example 1. Table 3 shows the results. When the weight average particle diameter of the dispersed rubber in the small particle portion is too large, it can be seen that the flexural modulus is lowered and a satisfactory physical property balance cannot be obtained.

[0060] except that a mixing ratio of the rubber-modified styrene resin A _III 50 parts by weight of B ₁ 50 parts by weight in Comparative Example 5 in Table 1 was subjected to a same manner as in Example 1. When the ratio of TI to RC in the small particle portion of the dispersed rubber is too large, it is understood that the MFR and the flexural modulus are reduced, and a satisfactory physical property balance cannot be obtained.

[0061] except that a mixing ratio of the rubber-modified styrene resin A _IV 50 parts by weight of B ₁ 50 parts by weight in Comparative Example 6 in Table 1 was subjected to a same manner as in Example 1. Table 3 shows the results. Particle size 1.0
It can be seen that if the ratio of salami particles in the μm dispersed rubber particles is too low, sufficient impact resistance is not exhibited.

Comparative Example 7 The same operation as in Example 1 was carried out except that 50 parts by weight of the rubber-modified styrene resin A _{1 and} 50 parts by weight of B _I in Table 1 were mixed. Table 3 shows the results. When the ratio of TI to RC in the large particle portion of the dispersed rubber is too large, it is found that the flexural modulus is lowered and a satisfactory balance of physical properties cannot be obtained.

Comparative Example 8 The same operation as in Example 1 was carried out except that 50 parts by weight of the rubber-modified styrene resin A _{1 and} 50 parts by weight of B _II in Table 1 were mixed. Table 3 shows the results. It can be seen that if the ratio of TI to RC in the large particle portion of the dispersed rubber is too small, sufficient impact resistance is not exhibited.

Comparative Example 9 The same procedure as in Example 1 was carried out except that 50 parts by weight of the rubber-modified styrene resin A _{1 and} 50 parts by weight of B _III in Table 1 were mixed. Table 3 shows the results. When the weight average particle diameter of the large particle portion of the dispersed rubber is too large, it is understood that the flexural modulus is lowered and a satisfactory balance of physical properties cannot be obtained.

Comparative Example 10 The same operation as in Example 1 was carried out except that 50 parts by weight of the rubber-modified styrene resin A _{1 and} 50 parts by weight of B _IV in Table 1 were mixed. Table 3 shows the results. When the weight average particle diameter of the dispersed rubber large particle part is too small, it is understood that sufficient impact resistance is not exhibited.

[0066]

[Table 3]

[0067]

According to the present invention, a resin composition having an excellent balance between moldability and mechanical properties after the self-extinguishing function is provided can be easily obtained. The self-extinguishing styrenic resin composition obtained by the present invention is required to be thinner, lighter, more complex, and larger, including housings for home electric appliances and OA equipment, automobile parts, and other mechanical parts. Can be widely used in various fields.

Claims (5)

[Claims] 1. A rubbery polymer dispersed in a matrix composed of an aromatic monovinyl polymer in the form of particles (A1) and (A2) below (A1); rubbery polymer content (RC: weight) %) Is 3 ~
20% by weight, the weight average particle diameter of the dispersed rubber particles is 0.4 to
The ratio of the number of rubber particles having a salami structure in dispersed rubber particles having a particle diameter of 1.0 μm or less is not less than 80%, and a toluene-insoluble content (TI: wt%) and a rubber-like polymer content (RC: weight) %), A rubber-modified styrenic resin having a ratio TI / RC of 2.4 or less; (A2); a rubbery polymer content (RC:% by weight) of 3 to
20% by weight, the weight average particle diameter of the dispersed rubber particles is 1.1 to
5.0 μm, the ratio TI / RC of the toluene-insoluble matter (TI: wt%) to the rubbery polymer content (RC: wt%) is 2 to 4
100 parts by weight of the mixed resin (A) of the rubber-modified styrenic resin (A), 1 to 50 parts by weight of the halogen-based flame retardant (B) and 0 to 30 parts by weight of the flame-retardant auxiliary (C) are blended, and an extruder is used. A method for producing a self-extinguishing styrenic resin composition, wherein the composition is melt-kneaded. 2. The total content of the rubbery polymer in the mixed resin (A) is 3 to 20% by weight, and 99 to 30% by weight of the total content of the rubbery polymer is from (A1). 1 to 70% by weight
The method for producing a self-extinguishing styrenic resin composition according to claim 1, wherein two kinds of rubber-modified styrenic resins are mixed so that is formed from (A2). 3. A mixed resin (A) wherein (A1) and (A2) have TI / RC smaller than the former and larger than the latter.
Or the manufacturing method of the self-extinguishing styrene resin composition of Claim 2. 4. The method for producing a self-extinguishing styrenic resin composition according to claim 1, wherein a bromine-based flame retardant having a melting point or a softening point of 200 ° C. or more is used as the halogen-based flame retardant (B). 5. The method for producing a self-extinguishing styrenic resin composition according to claim 1, wherein antimony trioxide is used as the flame retardant aid of the component (C).