JP3373334B2 - Thermoplastic resin composition and molded article thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition having excellent mechanical strength such as impact resistance and rigidity, and further having excellent surface impact after coating, and a molded product made from the same.

[0002]

2. Description of the Related Art Conventionally, aromatic polycarbonate resins are
It has excellent mechanical strength and electrical properties, and is widely used as an engineering plastic in various fields such as electricity, electronic equipment, automobiles, and security. However, aromatic polycarbonate resins have drawbacks such as low impact resistance at low temperatures, large change in impact resistance due to wall thickness, and poor chemical resistance to organic solvents such as gasoline and thinner. There were cases where use was restricted. Various methods have been proposed to remedy these drawbacks. For example, as a method for improving impact resistance, a method of blending an aromatic polycarbonate resin with an ABS resin is disclosed in JP-B-38-15225 and JP-B-55-27579, but impact resistance at low temperature is disclosed. Was not enough. As a method for improving impact resistance at low temperature, aromatic polycarbonate resin is added to polyorganosiloxane rubber component and polyalkyl (meth)
A method of blending a composite rubber in which an acrylate rubber component has an interpenetrating network structure is disclosed in JP-A-64-79257.
Japanese Unexamined Patent Publication No. HEI 6-26977 discloses a method of compounding an aromatic polycarbonate resin and an AS resin with a composite rubber in which an ABS resin, a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component have an interpenetrating network structure. 1897. However, these methods cannot sufficiently satisfy the surface impact property after coating.

[0003]

An object of the present invention is to provide a thermoplastic resin composition which is excellent in mechanical strength such as impact resistance and rigidity, and is also excellent in surface impact after coating.

The present inventor has conducted earnest studies to achieve the above object, and as a result, a compound rubber in which a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate component have an interpenetrating network structure in an aromatic polycarbonate resin, It was found that a thermoplastic resin composition having excellent mechanical strength such as impact resistance and rigidity as intended, and further excellent surface impact resistance after coating can be obtained by blending a polyolefin and a polyolefin, and arrived at the present invention. .

[0005]

That is, according to the present invention, (A) an aromatic polycarbonate resin of 99.4 to 80% by weight, (B) a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate component interpenetrate. 0.5 to 15% by weight of composite rubber having a network structure, and (C)
Provided is a thermoplastic resin composition comprising 0.1 to 5% by weight of a polyolefin, and a molded article made from the same.

The aromatic polycarbonate resin (A) used in the present invention is a resin usually used as an engineering resin, and is an aromatic polycarbonate obtained by reacting a dihydric phenol with a carbonate precursor by a solution method or a melting method. It is a resin.

The basic means of these manufacturing methods will be briefly described. In the reaction using, for example, phosgene as the carbonate precursor, the reaction is usually performed in the presence of an acid binder and a solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the solvent, for example, a halogenated hydrocarbon such as methylene chloride or chlorobenzene is used. A catalyst such as a tertiary amine or a quaternary ammonium salt may be used to accelerate the reaction. At that time, the reaction temperature is usually 0 to 40 ° C.
And the reaction time is several minutes to 5 hours.

The transesterification reaction using a carbonic acid diester as a carbonate precursor is a method in which a dihydric phenol component in a predetermined ratio is stirred with a carbonic acid diester while heating in an inert gas atmosphere to distill the alcohol or phenols produced. Done by. The reaction temperature varies depending on the boiling point of the alcohol or phenols produced, etc., but is usually in the range of 120 to 300 ° C. From the initial stage of the reaction, the reaction is completed while reducing the pressure to distill off the produced alcohol or phenols. Further, a catalyst usually used in transesterification reaction may be used to accelerate the reaction. Examples of the carbonic acid diester used in the transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and the like. Of these, diphenyl carbonate is particularly preferable.

Typical examples of the dihydric phenol used here include 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A) and bis (4-).
Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2, 2
-Bis (4-hydroxy3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) ether, 4,4'-dihydroxydiphenyl, bis (4
-Hydroxyphenyl) sulfide and bis (4-
Examples thereof include hydroxyphenyl) sulfone. Preferred dihydric phenol is bis (4-hydroxyphenyl)
It is an alkane, and bisphenol A is particularly preferable.

As the carbonate precursor, carbonyl halide, carbonate ester or haloformate is used, and specific examples thereof include phosgene, diphenyl carbonate or dihaloformate of dihydric phenol.

In producing the aromatic polycarbonate resin by reacting the above dihydric phenol with the carbonate precursor, the dihydric phenol may be used alone or in combination of two or more kinds, and the aromatic polycarbonate resin may be trifunctional or more than trifunctional. It may be a branched polycarbonate resin obtained by copolymerizing a polyfunctional aromatic compound or a mixture of two or more aromatic polycarbonate resins. Moreover, you may use a catalyst, a molecular weight regulator, and an antioxidant as needed.

Regarding the molecular weight of the aromatic polycarbonate resin, any molecular weight can be used. For example, when bisphenol A is used as the dihydric phenol and phosgene is used as the carbonate precursor to obtain the aromatic polycarbonate resin, the concentration is 0.7 g. / Dl methylene chloride solution has a specific viscosity (ηsp) of 0.15 measured at a temperature of 20 ° C.
The thing of -1.5 is preferable.

The (B) composite rubber used in the present invention is 2
It has a structure in which the cross-linked networks of the various rubber components are entangled with each other. Therefore, the respective rubber components cannot be separated and extracted with a normal organic solvent such as acetone and toluene. Of the two rubber components constituting this composite rubber, one rubber component is a polyorganosiloxane rubber component and the other rubber component is a polyalkyl (meth) acrylate rubber component. By compounding this composite rubber, a molded article having excellent impact strength can be obtained. However, it is difficult to obtain a molded article having high impact strength even if the polyorganosiloxane rubber component and the polyalkyl (meth) acrylate rubber component constituting the composite rubber are used alone or simply by mixing them. Therefore, in the present invention, the composite rubber has a structure having excellent impact resistance due to the structure in which the above-mentioned two kinds of rubber components constituting them are entwined with each other through the cross-linking network, that is, the structure in which the composite rubber is integrated. Believed to give a gift.

The composite rubber in the present invention comprises 10 to 90% by weight of a polyorganosiloxane rubber component and 90 to 10% by weight of a polyalkyl (meth) acrylate rubber component (the total amount of each rubber component is 100% by weight). The rubber components are entangled with each other, and the average particle size is 0.08 to
The composite rubber has a thickness of 0.6 μm, and particularly preferably a composite rubber graft copolymer in which one or more vinyl monomers are graft-polymerized. When the polyorganosiloxane rubber component constituting the composite rubber exceeds 90% by weight, the surface appearance of the molded product is deteriorated, and when the polyalkyl (meth) acrylate rubber component exceeds 90% by weight, the impact resistance of the molded product is high. Since both of the two rubber components are 10 to 90% by weight (however, the total amount of both rubber components is 100% by weight), the property is deteriorated.
Weight percent is particularly preferred.

The average particle size of the composite rubber is 0.08-0.
6 μm is preferable. If the average particle size is smaller than 0.08 μm, the impact resistance of the molded product is lowered, and if it is larger than 0.6 μm, the impact resistance of the molded product is reduced and the appearance is also deteriorated, which is not preferable.

The emulsion polymerization method is most suitable for producing the composite rubber having the above-mentioned average particle diameter. First, the latex of the polyorganosiloxane rubber is prepared, and then the alkyl (meth) acrylate rubber monomer is added. It is preferred to impregnate the rubber particles of the polyorganosiloxane rubber latex before polymerizing the above monomers.

The polyorganosiloxane rubber component constituting the above composite rubber can be prepared by emulsion polymerization using an organosiloxane and a cross-linking agent, and a graft crossing agent can also be used in combination therewith. Examples of the organosiloxane include various cyclic compounds having a 3-membered ring or more, and a 3- to 6-membered ring is preferably used. For example, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentanesiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethylphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, and the like, These may be used alone or in combination of two or more. The amount of these used is 50% by weight or more, preferably 70% by weight or more in the polyorganosiloxane rubber component.

As the crosslinking agent, a trifunctional or tetrafunctional silane-based crosslinking agent such as trimethoxymethylsilane,
Triethoxyphenylsilane, tetramethoxysilane,
Tetraethoxysilane, tetra-n-propoxysilane, tetrabutoxysilane, etc. are used. Particularly, a tetrafunctional crosslinking agent is preferable, and tetraethoxysilane is particularly preferable. The amount of the cross-linking agent used is 0.1 to 30% by weight in the polyorganosiloxane rubber component.

As the graft crossing agent, (meth) acryloyloxysiloxane is suitable, and methacryloyloxysiloxane is particularly preferable. Specific examples of this methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane,
γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane Examples include silane.
The amount of the graft crossing agent used is 0 to 10% by weight in the polyorganosiloxane rubber component.

The latex of the polyorganosiloxane rubber component is produced, for example, by preparing a mixed solution of an organosiloxane, a crosslinking agent and, if desired, a graft crossing agent, in the presence of a sulfonic acid emulsifier such as alkylbenzene sulfonic acid or alkyl sulfonic acid. It is preferably produced by shear mixing with water using, for example, a homogenizer. Alkylbenzene sulfonic acid is suitable because it acts as an emulsifier of the organosiloxane and at the same time serves as a polymerization initiator. At this time, it is preferable to use a metal salt of alkylbenzene sulfonic acid, a metal salt of alkyl sulfonic acid, etc. in combination because it is effective in maintaining the polymer stably during the graft polymerization.

Next, the polyalkyl (meth) acrylate rubber component constituting the above composite rubber can be synthesized by using the following alkyl (meth) acrylate, crosslinking agent and graft crossing agent. Examples of alkyl (meth) acrylates include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and hexyl methacrylate.
Alkyl methacrylates such as -ethylhexyl methacrylate and n-lauryl methacrylate may be mentioned, and the use of n-butyl acrylate is particularly preferable.

Examples of the cross-linking agent include ethylene glycol methacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, and 1,4-butylene glycol dimethacrylate.

Examples of the graft crossing agent include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate and the like. Allyl methacrylate can also be used as a crosslinking agent. These crosslinking agents and graft crossing agents may be used alone or in combination of two or more. The total amount of the cross-linking agent and the graft crossing agent used is 0.1 to 20% by weight in the polyalkyl (meth) acrylate rubber component.

The polymerization of the polyalkyl (meth) acrylate rubber component is carried out by adding the above alkyl (meth) acrylate to the latex of the polyorganosiloxane rubber component neutralized by the addition of an aqueous solution of an alkali such as sodium hydroxide, potassium hydroxide or sodium carbonate. ) After adding an acrylate, a cross-linking agent and a graft crossing agent and impregnating the polyorganosiloxane rubber particles, a general radical polymerization initiator is allowed to act. As the polymerization progresses, a crosslinked network of polyalkyl (meth) acrylate rubber entangled with each other in the crosslinked network of polyorganosiloxane rubber is formed, and the polyorganosiloxane rubber component and the polyalkyl (meth) acrylate rubber component which are substantially inseparable A composite rubber latex is obtained.

This composite rubber was mixed with toluene at 90 ° C. for 1 hour.
The gel content measured by extracting for 2 hours is 80% by weight or more.

Examples of vinyl monomers that can be graft-polymerized to this composite rubber include aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene, and methacryl such as methylmethacrylate and 2-ethylhexylmethacrylate. Various vinyl monomers such as acid esters, acrylic acid esters such as methyl acrylate, ethyl acrylate and butyl acrylate, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and the like may be used alone or in combination. Can be used.

The ratio of the composite rubber to the vinyl monomer is
Based on the weight of the obtained graft copolymer, the composite rubber is 30 to 95% by weight, preferably 40 to 90% by weight and the vinyl monomer is 5 to 70% by weight, preferably 10 to 60%.
Weight percent is preferred.

The compounding amount of the composite rubber in the present invention is 0.5 to 1 per 100% by weight of the total of the thermoplastic resin composition.
It is 5% by weight, preferably 1 to 10% by weight. If it is less than 0.5% by weight, the impact resistance is lowered,
If it exceeds 5% by weight, the rigidity is lowered, which is not preferable.

The (C) polyolefin used in the present invention may be a commercially available product produced by a general production method. By blending this polyolefin, the chemical resistance is improved, and therefore a molded article having excellent surface impact after coating can be obtained. Examples of the polyolefin include low density polyethylene, high density polyethylene, polypropylene, polymethylpentene-1, and the like, and two or more kinds of these may be used in combination.

The amount of the polyolefin compounded in the present invention is 100% by weight based on the total weight of the thermoplastic resin composition.
0.1 to 5% by weight, preferably 0.5 to 3% by weight
Is preferred. When the content of polyolefin is less than 0.1% by weight, the surface impact property after coating is lowered, and when it exceeds 5% by weight, layer peeling occurs in the molded product and the appearance is deteriorated, which is not preferable.

Any method may be used to produce the thermoplastic resin composition of the present invention. For example, an aromatic polycarbonate resin, a composite rubber in which a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component have an interpenetrating network structure, a polyolefin, and other additives as appropriate, such as a V-type blender, are used. It can be produced by a method generally used in industry, such as a method of sufficiently mixing using a mixing means and then pelletizing with a vent type uniaxial ruder or the like.

Further, flame retardants, flame retardant auxiliaries, heat stabilizers, antioxidants, light stabilizers, colorants, lubricants, release agents, antistatic agents, within the range not impairing the objects and effects of the present invention. Etc. may be blended, and other thermoplastic resins may be blended.

The resin composition thus obtained can be molded by any method such as injection molding, compression molding or rotational molding. Examples of these molded products can be used in many fields such as housings of various devices in the fields of electric and electronic devices, instrument panels, exterior parts and interior parts in the field of automobiles, helmets, shields, signal light bodies in the field of security. . However, the molded product molded from the thermoplastic resin composition of the present invention is not limited to these examples.

[0034]

Examples 1 to 6 and Comparative Examples 1 to 4 The present invention will be described in more detail below with reference to examples. Aromatic polycarbonate resin, composite rubber, and polyolefin were mixed in the ratio shown in Table 1, and the extruder (manufactured by Nakatani Co., Ltd., 30 mmφ) was used.
Pelletized at a cylinder temperature of 280 ° C. by a vent type extruder, dried at 120 ° C. for 5 hours, and then injection-molded (F-NAC Co., Ltd. T-150D).
Various test pieces were prepared at a cylinder temperature of 280 ° C. and a mold temperature of 70 ° C., and each evaluation was performed using these test pieces. The evaluation results are shown in Table 1. The symbols showing the components shown in Table 1 are as follows.

PC: Aromatic polycarbonate resin [Panlite L-1225 manufactured by Teijin Chemicals, ηsp =
0.41] S-2001: Composite rubber [Mitsubishi Rayon Co., Ltd. METABLEN S-2001] RK-200: Composite rubber [Mitsubishi Rayon Co., Ltd. METABLEN RK-200] PE: High density polyethylene [Mitsui Petrochemical Industry Co., Ltd. Hi-Zex 2100JP, specific gravity = 0.957]

The evaluation was carried out by the following method. (1) Impact strength: 1/4 "according to ASTM D256
The notched Izod impact strength was measured.

(2) Flexural modulus: The flexural modulus was measured according to ASTM D790.

(3) Appearance: 75 mm × 75 mm × 2 mm
The appearance of the test piece of t (thickness) was visually determined and evaluated according to the following criteria. ○: Good appearance (no layer peeling) ×: Poor appearance (layer peeling) (4) DuPont surface impact coating after coating: 75 mm × 75 mm × 2 mmt (thickness) on one side of a test piece of Nippon Bee Chemical Co., Ltd. ) R-230 Dover White was applied and dried at 80 ° C. for 1 hour. The thickness of the coating film at this time was 30 μm.

Evaluation: The coated surface of the test piece was placed upward with both ends free, 12.5 mmφ and tip R = 3.
Place a 2mm steel hammer on it and weigh 2kg on it.
The height at which the steel ball was dropped and measured was measured.

[0040]

[Table 1]

[0041]

INDUSTRIAL APPLICABILITY The thermoplastic resin composition of the present invention is excellent in mechanical strength such as impact resistance and rigidity, and is also excellent in surface impact after coating, and is used in various industries such as automobile field and safety field. Useful for applications.

Claims (2)

(57) [Claims] 1. (A) Aromatic polycarbonate resin 9
9.4-80 wt%, (B) Polyorganosiloxane rubber component and polyalkyl (meth) acrylate rubber component composite rubber 0.5-1 having an interpenetrating network structure
A thermoplastic resin composition consisting essentially of 5% by weight and (C) a polyolefin of 0.1 to 5% by weight. 2. A molded product obtained by molding the thermoplastic resin composition according to claim 1.