JP3399701B2 - 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 impact resistance and penetration resistance, and a molded article made of the same.

[0002]

2. Description of the Related Art Aromatic polycarbonate resins are widely used as engineering plastics having excellent mechanical strength and electric properties in various fields such as electric fields, electronic equipment fields, automobile fields, and security fields.
Especially for helmet applications, glass fiber reinforced thermosetting resin has been used in the past, but recently, helmet weight reduction,
In addition, from the viewpoint of workability when manufacturing helmets, the use of aromatic polycarbonate resin, which has excellent mechanical strength, is increasing. However, the aromatic polycarbonate resin has drawbacks such as impact resistance at low temperature and a large change in impact resistance due to wall thickness. In particular, the low notched Izod impact strength at low temperatures and the low 1/4 "notched Izod impact strength mean that the helmet may be used in low temperature atmosphere or due to the effect of minute scratches on the helmet surface during use. It means that the impact strength of No. 1 was decreased, and it was necessary to improve these defects.
Various methods have been proposed so far in order to improve these drawbacks. For example, a method of blending an aromatic polycarbonate resin with a composite rubber in which a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component have an interpenetrating network structure is disclosed in JP-A-64-792.
Japanese Patent Application Laid-Open No. 57-57980, and 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. It is disclosed in Japanese Unexamined Patent Publication No. 6-1897. However, although the impact resistance at low temperature is improved by these methods, the method of JP-A-64-79257 adds a large amount of the composite rubber, and therefore JP-A-6-1897.
In the publication, since AS resin and ABS resin are added, a penetration resistance test (JIS T 8
The vertical distance from the upper end of the top ring of the test jig, which is the standard value of 131), to the lowest point of the depression of the molded product is 15 m.
It could not be satisfied that it is less than m.

[0003]

An object of the present invention is to provide a thermoplastic resin composition having excellent impact resistance and penetration resistance.

As a result of intensive studies to achieve the above object, the present inventor has found that an aromatic polycarbonate resin has a polyorganosiloxane rubber component and a polyalkyl (meth).
It has been found that a target thermoplastic resin composition having excellent impact resistance and penetration resistance can be obtained by compounding a specific amount of a composite rubber having an interpenetrating network structure as an acrylate component, and arrived at the present invention.

[0005]

That is, according to the present invention, (A) 99 to 95 % by weight of an aromatic polycarbonate resin, (B) a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate component are interpenetrating network structures. Having an average particle diameter of 0.08 to 0.6 μm
That substantially consisting a thermoplastic resin composition and a molded article therefrom is provided from the compound rubber 1 to 5% by weight. Further, the thermoplastic resin composition has a temperature of 23 ° C. according to JIS T 8
Penetration resistance by 131 is less than 15 mm, 1/4 "notched Izod impact strength by ASTM D256 at 23 ° C is 45 kgfcm / cm or more, 1/4" notched Izod impact strength by ASTM D256 at -30 ° C is 20 kgfcm / cm or more Is to have.

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.
It is 6 μm. 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
30-95% by weight of composite rubber, preferably 40-90% by weight and 5-70% by weight of vinyl monomer, preferably 10-6, based on the weight of the obtained graft copolymer.
0% by weight is preferred.

The compounding amount of the composite rubber in the present invention is from 1 to.
It is in the range of 5% by weight . If it is less than 0.5% by weight, impact resistance is lowered, and if it exceeds 8% by weight, penetration resistance is lowered, which is not preferable.

Any method may be employed 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, and other additives as appropriate, for example, a mixing means such as a V-type blender. It can be produced by a method generally used in industry, such as a method of pelletizing with a vent type uniaxial ruder or the like after sufficiently mixing with.

Further, flame retardants, flame retardant aids, heat stabilizers, antioxidants, light stabilizers, colorants, lubricants, mold release agents, antistatic agents, within the range not impairing the objects and effects of the present invention, You may mix these. Moreover, you may mix | blend another thermoplastic resin.

The resin composition thus obtained can be molded by any method such as injection molding, compression molding or rotational molding.

[0032]

EXAMPLES 1 TO 4 AND COMPARATIVE EXAMPLES 1 TO 2 The present invention will be described in more detail below with reference to Examples. The components shown below were mixed in the proportions shown in Table 1 to give Examples 1 to 4 and Comparative Example 1
No. 2 is pelletized by an extruder (30 mmφ vent type extruder manufactured by Nakatani Co., Ltd.) at a cylinder temperature of 280 ° C., and the pellets are dried at 120 ° C. for 5 hours, and then an injection molding machine (T-manufactured by FANUC Co., Ltd.). 150D), various test pieces were prepared at a cylinder temperature of 280 ° C. and a mold temperature of 70 ° C., and each test piece was evaluated. 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]

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) Penetration resistance: Average wall thickness is 1.5 mmt
Was molded, and the vertical distance from the upper end of the top ring of the test jig to the lowest point of the depression of the molded product was measured according to JIS T8131.

[0036]

[Table 1]

[0037]

INDUSTRIAL APPLICABILITY The thermoplastic resin composition of the present invention is excellent in impact resistance and penetration resistance, and is useful for various industrial applications such as automobile fields and safety fields.

Claims (2)

(57) [Claims] 1. (A) Aromatic polycarbonate resin 99
To 95 % by weight, the (B) polyorganosiloxane rubber component and the polyalkyl (meth) acrylate rubber component have an interpenetrating network structure, and the average particle size is 0.0.
A thermoplastic resin composition consisting essentially of 1 to 5 % by weight of a composite rubber having a size of 8 to 0.6 μm, and having a J value at 23 ° C.
Penetration resistance according to IST 8131 is less than 15 mm
1/4 "according to ASTM D256 at 23 ° C
Notched Izod impact strength is 45 kgfcm / cm
And above, according to ASTM D256 at -30 ° C.
1/4 "notched Izod impact strength is 20kgf
A thermoplastic resin composition having a cm / cm or more . 2. A by molding the thermoplastic resin composition of claim 1 Symbol mounting moldings.