JPH09176440A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition having excellent chemical resistance and slidability, improved sound damping qualities and good laser markability by mixing a mixture comprising a polyester resin and a rubbery graft copolymer with a specified multiphase structure thermoplastic resin. SOLUTION: This resin composition is prepared by mixing 100 pts.wt. resin mixture comprising 25-70wt.% polyester resin having an intrinsic viscosity of 0.5-1.4 and 30-75wt.% polymer based on a rubbery graft copolymer prepared by grafting 20-95wt.% vinyl monomer onto 5-80wt.% rubbery polymer with 3-15 pts.wt. multiphase structure thermoplastic resin comprising 5-95wt.% dispersed particles comprising a polyolefin (co)polymer and having a particle diameter of 0.001-10μm and 95-5wt.% vinyl copolymer comprising at least one vinyl monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin used for molding materials required to have slidability such as electric / electronic mechanical parts, office automation equipment such as key tops of personal computers, keyboard parts, automobile parts and the like. More specifically, the present invention relates to a thermoplastic resin composition having excellent chemical resistance, and particularly excellent color development property with respect to laser marking property.

[0002]

2. Description of the Related Art Polyester resins represented by polyethylene terephthalate and polybutylene terephthalate are
It has excellent moldability, mechanical properties, heat resistance, and chemical resistance.
Widely used as electric parts and automobile parts.
However, the abrasion resistance, abrasion resistance and impact resistance were not sufficient. The present inventors have proposed a method of blending polybutylene terephthalate with a thermoplastic resin having a multi-phase structure as a method of improving these drawbacks (Japanese Patent Laid-Open No. 5-22).
2278).

However, although these materials have excellent slidability, when used as materials for laser marking, satisfactory coloring properties were not obtained.

On the other hand, ABS resin is excellent in moldability, appearance and impact resistance, and is widely used as a material for various housings, and is also used as a laser marking material. However, ABS resin is not sufficient in chemical resistance and slidability, and when ABS resin is used as a sliding member, abrasion cannot be remarkably used.

Therefore, key tops, key bases, etc. of personal computers were previously made by secondary processing such as sublimation printing and tampo printing using polybutylene terephthalate, but in recent years, laser marking has been developed. At the same time, it is being changed to ABS resin for the above reason.

However, due to the problems of chemical resistance and slidability, which are the drawbacks of ABS resin, it is necessary to limit the places to be used, apply grease to improve slidability, or perform Teflon coating. This is an obstacle to the rationalization of manufacturing of key tops and key bases for personal computers.

[0007]

The object of the present invention is to improve chemical resistance so that it can be used anywhere regardless of where it is used, and has excellent slidability and reduced rigidity. In this way, it is possible to obtain a thermoplastic resin composition having improved sound deadening property and good laser marking property.

[0008]

In view of such circumstances, the present inventor has found that a resin mixture composed of a polyester resin and a polymer mainly composed of a rubber-like graft copolymer has a specific polyolefin (co) weight. By blending the thermoplastic resin with multi-phase structure consisting of coalesced, the abrasion resistance, abrasion resistance,
The inventors have found that a thermoplastic resin composition having excellent impact resistance, sound deadening properties, and laser marking properties can be obtained, and have reached the present invention.

That is, the gist of the present invention is as follows.
100 parts by weight of a resin mixture consisting of 25 to 70% by weight of a polyester resin (A) and 30 to 75% by weight of a polymer (B) mainly composed of a rubbery graft copolymer contains a polyolefin (co) polymer. Multiphase thermoplastic resin (C) 3
-15 parts by weight of the thermoplastic resin composition.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin (A) in the present invention is obtained by subjecting an aromatic dicarboxylic acid or an ester-forming derivative thereof and a monomer having a diol or an ester-forming derivative as a main component to a condensation reaction. The resulting (co) polymer.

In the present invention, the aromatic dicarboxylic acid used as the acid component is terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid,
1,5-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,
4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, etc. are mentioned, and these ester-forming derivatives include their dialkyl esters, diaryl esters, etc.

As the diol component used in the present invention, ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 16-hexanediol, decamethylene glycol, cyclohexanedimethanol, etc. An aliphatic diol having 2 to 10 carbon atoms, polyethylene glycol, poly-1,
Examples include long-chain glycols having a molecular weight of 400 to 6000 such as 3-propylene glycol and polytetramethylene glycol.

Polyester resins obtained from such aromatic dicarboxylic acid components and diol components include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyhexamethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-. Examples thereof include naphthalate and the like, or copolymers containing these as the main components.
Among them, polyethylene terephthalate and polybutylene terephthalate are preferable because they have appropriate mechanical strength.

These polyester resins are phenol /
In a mixed solvent of tetrachloroethane (mixing ratio is 1: 1 by weight), the intrinsic viscosity [η] at a temperature of 23 ° C. is 0.5.
It is preferable that it is ~ 1.4. This is because when the intrinsic viscosity is less than 0.5, the strength of the molded product obtained from the thermoplastic resin composition of the present invention tends to decrease, and when it exceeds 1.4, the fluidity at the time of molding decreases and the filling property becomes low. This is because there is a risk that the

The rubber-like graft copolymer in the polymer (B) mainly composed of the rubber-like graft copolymer in the present invention is a rubber-like polymer obtained by graft-polymerizing a vinyl monomer. As the rubber-like polymer, an elastomer such as a diene rubber, an acrylic rubber, an EPDM rubber, a chlorinated polyethylene rubber, a silicone rubber, a silicone-acrylic composite rubber can be used, and a polybutadiene rubber and a butadiene copolymer are preferable. It is a rubber, for example, a butadiene copolymer rubber obtained by copolymerizing monomers such as about 30% by weight of acrylonitrile, (meth) acrylic acid ester and styrene.

The vinyl-based monomer used in the rubber-like graft copolymer is an aromatic vinyl-based monomer or (meth).
It is at least one vinyl-based monomer selected from the group consisting of acrylic acid ester-based monomers and vinyl cyanide-based monomers. Aromatic vinyl monomers that can be used in the present invention include styrene, α-methylstyrene, halogenated styrenes such as chlorostyrene and bromostyrene, and alkylstyrenes such as vinyltoluene, which are used alone or in combination of two or more. Used as a mixture. Styrene or α
-Methylstyrene is preferably used alone or as a mixture of two kinds.

The (meth) acrylic acid ester-based monomer that can be used in the present invention is methyl acrylate,
Methyl methacrylate, methyl ethacrylate, ethyl acrylate, ethyl methacrylate, ethyl ethacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate and the like and derivatives thereof. These can be used alone or in combination of two or more. Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, butyl acrylate and the like are preferable.

The vinyl cyanide-based monomers that can be used in the present invention are acrylonitrile, halogenated acrylonitrile, methacrylonitrile, ethacrylonitrile, etc. and their derivatives, which may be used alone or in combination. One or more species can be used in combination. Preferred is acrylonitrile and / or methacrylonitrile.

Further, in the present invention, if necessary,
Other vinyl-based monomers, for example, maleimide-based monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide and derivatives thereof, acrylamide and derivatives thereof, and the like can be used.

The composition ratio of the rubber-like polymer and the vinyl-based monomer unit in the rubber-like graft copolymer is 5 to 80% by weight, preferably 5 to 70% by weight, the vinyl-based monomer. Unit 20-95% by weight, preferably 30-95
% By weight. If the content of the rubber-like polymer is less than 5% by weight, impact resistance is insufficient, and if it exceeds 80% by weight, the hardness of the resin is insufficient, which is not preferable.

The composition ratio of the aromatic vinyl-based monomer unit and / or the (meth) acrylic acid ester-based monomer unit and the vinyl cyanide-based monomer unit in the rubber-like graft copolymer is Vinyl monomer unit and /
Or (meth) acrylic acid ester-based monomer unit 30 to
99% by weight, preferably 50 to 90% by weight, vinyl cyanide monomer unit 1 to 70% by weight, preferably 10 to 5%
0% by weight. When the aromatic vinyl monomer unit is 30% by weight or less, the fluidity of the resin is insufficient, and when the vinyl cyanide monomer unit is 1% by weight or less, the chemical resistance of the resin is low. It is not preferable because it deteriorates the property.

If desired, a vinyl (co) polymer may be added to the rubber-like graft copolymer. The vinyl-based (co) polymer is at least one vinyl-based monomer selected from the group consisting of aromatic vinyl-based monomers, (meth) acrylic acid ester-based monomers, and vinyl cyanide-based monomers. (Co) polymer obtained from As the aromatic vinyl-based monomer that can be used here, the same ones as those used above can be used. If necessary, other vinyl-based monomers such as maleimide, N-methylmaleimide, N-
It is also possible to use maleimide-based monomers such as phenylmaleimide and derivatives thereof, and glycidyl methacrylate and derivatives thereof.

Examples of vinyl-based (co) polymers are methyl methacrylate polymer, acrylonitrile-styrene copolymer, acrylonitrile-α-methylstyrene copolymer, styrene-N-phenylmaleimide copolymer, acrylonitrile- Examples thereof include styrene-N-phenylmaleimide terpolymer.

The vinyl-based (co) polymer may be composed of a single vinyl-based monomer unit, but it may be composed of 30 to 95% by weight of an aromatic vinyl-based monomer unit and a (meth) acrylic acid ester-based monomer unit. Those composed of 5 to 70% by weight of a monomer unit and / or vinyl cyanide monomer unit and 0 to 40% by weight of a maleimide monomer unit are preferable. Furthermore, aromatic vinyl-based monomer units 50 to 85% by weight, (meth) acrylic acid ester-based monomer units and / or vinyl cyanide-based monomer units 15 to 50% by weight, and maleimide-based monomer units. It is preferably composed of 0 to 30% by weight. If the amount of the aromatic vinyl monomer unit is less than 30% by weight, the fluidity of the resin will be insufficient, and if the amount of the vinyl cyanide monomer unit is less than 5% by weight, the chemical resistance of the resin will be poor.

The proportion of the vinyl-based (co) polymer used is 0 to 60% by weight in the resin composition comprising the rubber-based graft copolymer and the vinyl-based (co) polymer.

Polyester resin (A) in the present invention
Is 2 in a resin mixture composed of a polyester resin (A) and a polymer (B) mainly composed of a rubbery graft copolymer.
It is used in the range of 5 to 70% by weight. This is because if it is less than 25% by weight, chemical resistance and slidability are inferior, and if it exceeds 70% by weight, color development in laser marking is inferior. Preferably it is 30 to 60% by weight.

The multi-phase structure thermoplastic resin (C) in the present invention is used for enhancing slidability, and is 5 to 95% by weight of a polyolefin (co) polymer and 95 to 5 of a vinyl (co) polymer. It is preferable that the graft copolymer comprises 20 wt% to 90 wt% of the polyolefin (co) polymer and 80 wt% to 10 wt% of the vinyl (co) polymer. This is a polyolefin type (co)
If the amount of the polymer is less than 5% by weight, the effect of improving the abrasion resistance, abrasion resistance and impact resistance may be insufficient. On the contrary, if the amount of the polymer exceeds 95% by weight, the polyester resin (A) and the rubber-like graft may both be reduced. This is because the dispersion in the polymer (B) containing the polymer as the main component tends to be poor.

Further, it is more preferable to disperse the resin uniformly in the form of particles in a resin mixture of the polyester resin (A) and the polymer (B) mainly composed of a rubbery graft copolymer. In this case, the particle size of the dispersed particles is 0.001
10 to 10 μm is preferable, and 0.01 to 5 is more preferable.
μm. This is because if the particle size is less than 0.001 μm, the impact resistance is not sufficient, and conversely if it exceeds 10 μm, the impact resistance, abrasion resistance and abrasion resistance cannot be improved.

As the above-mentioned polyolefin (co) polymer, low density, medium density, high density polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-
1 etc. homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1
Copolymers composed of ethylene and other α-olefins such as copolymers, ethylene-4-methylpentene-1 copolymers, ethylene-octene-1 copolymers, etc., containing ethylene as a main component, propylene-ethylene block Copolymers consisting of propylene and other α-olefins such as copolymers and containing propylene as a main component, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, ethylene Of acrylic acid or methacrylic acid with esters of methyl, ethyl, propyl, isopropyl, butyl, etc., ethylene-maleic acid copolymer, ethylene-propylene copolymer rubber, ethylene-propylene-diene-copolymer Rubber, liquid polybutadiene, ethylene-vinyl acetate-vinyl chloride copolymer and mixtures thereof, Examples thereof include a mixture of these and a different kind of synthetic resin or rubber.

The vinyl-based (co) polymer means an aromatic vinyl-based monomer, a (meth) acrylic acid ester monomer, a (meth) acrylonitrile monomer, a vinyl ester monomer, (meth) ) A (co) polymer obtained by polymerizing at least one vinyl monomer selected from the group consisting of acrylamide monomers, and specifically, styrene, methylstyrene, dimethylstyrene, ethylstyrene, Isopropylstyrene, chlorostyrene, α-methylstyrene, α-ethylstyrene, methyl (meth) acrylate,
Ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, vinyl acetate, vinyl propylate,
Examples thereof include vinyl monomers such as maleic acid monoester, maleic acid diester, maleic anhydride monoester and maleic anhydride diester.

Among these, aromatic vinyl monomers,
It is preferable to use a (meth) acrylic acid ester monomer, a (meth) acrylonitrile monomer and a vinyl ester monomer. In particular, a vinyl (co) polymer such as an acrylonitrile-styrene copolymer containing 50% by weight or more of an aromatic vinyl-based monomer unit is preferable because it is well dispersed in the polyester resin (A).

The number average degree of polymerization of the vinyl (co) polymer is preferably in the range of 5 to 10,000, and more preferably in the range of 10 to 5,000. This is because when the number average degree of polymerization is less than 5, the heat resistance of the composition is lowered, and conversely 1000
This is because if it exceeds 0, the melt viscosity increases, the moldability is impaired, and the surface gloss decreases.

Further, the blending amount of the thermoplastic resin (C) having a multi-phase structure containing a polyolefin (co) polymer is the same as that of the polyester resin (A) and the polymer (B) mainly composed of the rubber-like graft copolymer. 3 to 15 parts by weight with respect to 100 parts by weight of the resin mixture consisting of. This is because if it is less than 3 parts by weight, the sliding property is not improved, and if it exceeds 15 parts by weight, the coloring property by laser marking is poor. Preferably, it is 5 to 11 parts by weight.

In the present invention, coloring containing a nucleating agent such as talc, a lubricant such as silica or stearate or a mold release agent, an ultraviolet absorber, a pigment such as carbon black, etc., within the range that does not impair the effects of the present invention. Known additives such as agents, flame retardants such as halogen compounds and phosphorus compounds, flame retardant aids, antioxidants, and heat stabilizers may be optionally added.

[0035]

The present invention will be specifically described below with reference to examples.

In the examples, the flexural modulus and Izod impact strength of resin pellets shown in Tables 1 and 2 were measured using an in-line screw injection molding machine at a cylinder temperature of 250 ° C., a mold temperature of 80 ° C. and a molding cycle of 30. In seconds, the flexural modulus is calculated according to ASTM-D790.
The Izod impact strength was measured according to M-D256.
For the evaluation of chemical resistance, a 150 mm square × t2 mm molded product was obtained in the same manner as the test piece used for the measurement of the Izod impact,
A 35 mm x 120 mm x t2 mm test piece was cut out from the molded product, and the chemical was Morikort EM-60L.
(Manufactured by Dow Corning Co., Ltd.), a 1/4 ellipse test was carried out by the method shown in FIG. 1, and the minimum strain value (critical strain value%) of occurrence of cracks was referred to with reference to the symbol shown in FIG. ) Was calculated according to the following equation. In addition, t is the thickness (mm) of the test piece,
x represents the distance (mm) to the critical point of crack generation.

Critical strain value (%) = 0.139 (1-0.
00617X ^{2) -3/2} t critical strain value is evaluated as follows.

˜2.0 (%): No crack is generated even with large strain 2.0 to 0.8 (%): Crack is generated when the strain is large 0.8 to 0.5 (%): Slightly large strain 0.5-0.3 (%): Cracks occur even with a small strain 0.3-(%): Cracks occur even with residual strain Regarding the sound deadening property, a box-shaped molded product of 15 mm × 25 mm × H10 mm is prepared as described above. Obtained in the same manner as the test piece used for measuring flexural modulus and Izod impact, acrylonitrile 25 parts by weight, styrene 60 parts by weight, polybutadiene 15
A 100 mm square × t3 mm plate of ABS resin consisting of parts by weight is obtained in the same manner as above, and this is used as a mating material.
As shown in FIG. 2, a coil-shaped spring was inserted between these molded products to confirm the spotting test. The evaluation was performed as follows.

⊚: Most favorable and low sound ◯: Good and low sound Δ: Slightly high sound ×: High sound The slidability was evaluated using the resin pellets shown in Tables 1 and 2.
A ring having an outer diameter of 25.6 mm, an inner diameter of 20.0 mm, and a height of 15 mm was obtained in the same manner as the test piece used for the measurement of the Izod impact, and this was used as a test piece. EFM-3-E) manufactured by EFM-3-E), the fixed side is a resin pellet shown in Tables 1 and 2, the rotating side is an ABS resin composed of 25 parts by weight of acrylonitrile, 60 parts by weight of styrene, and 15 parts by weight of polybutadiene, and a sliding speed of 20 cm / sec. , A load of 1 Kgf and a running time of 24 hours were tested, and the friction coefficient and the specific wear amount were measured.

Evaluation of laser marking property is 80 mm
A plate of x50 mm x t3 mm was molded under the above-mentioned molding conditions to give a test piece for evaluation. The test piece was used to confirm the contrast and surface condition under each laser marking output condition. The evaluation was performed as follows.

⊚: Most good color development ◯: Good color development Δ: Some poor color development ×: Poor color development (Examples 1 to 4) (A) and (B) at the ratios shown in Table 1.
Each of (C) was blended and uniformly mixed in a V-type blender for 5 minutes. This mixture was put into a vent-type melt extruder having a diameter of 45 mm and extruded at a cylinder temperature of 250 ° C. to obtain resin pellets. The above evaluation was performed using the obtained resin pellets. The results are shown in Table 1.

Here, as (A), the intrinsic viscosity [η]
Polybutylene terephthalate of 1.0 is used as (B), an ABS resin composed of 25 parts by weight of acrylonitrile, 58 parts by weight of styrene, and 17 parts by weight of polybutadiene,
As (C) -1, a multi-phase structure thermoplastic resin composed of 50 parts by weight of low density polyethylene and 50 parts by weight of acrylonitrile-styrene copolymer was used.

[0043]

[Table 1]

(Comparative Examples 1 to 8) (A), (B) and (C) were blended in the proportions shown in Table 2 and extruded in the same manner as in Examples 1 to 4 to obtain resin pellets.

The resin pellets thus obtained were evaluated in the same manner as in the examples. The results are shown in Table 2.

Here, as (A), the intrinsic viscosity [η]
Polybutylene terephthalate of 1.0 is used as (B), an ABS resin composed of 25 parts by weight of acrylonitrile, 58 parts by weight of styrene, and 17 parts by weight of polybutadiene,
As (C) -1, a thermoplastic resin having a multiphase structure consisting of 50 parts by weight of low-density polyethylene and 50 parts by weight of acrylonitrile-styrene copolymer, and low-density polyethylene as (C) -2 were used.

[0047]

[Table 2]

From the above results shown in Tables 1 and 2, the thermoplastic resin composition of the present invention was compared with the conventional composition,
It was revealed that it is excellent in slidability, chemical resistance, noise reduction and laser marking.

[0049]

EFFECT OF THE INVENTION The thermoplastic resin composition of the present invention has a sliding property obtained by blending a multiphase thermoplastic resin into a resin mixture composed of a polyester resin and a polymer mainly composed of a rubber-like graft copolymer. , Which can improve chemical resistance and can also obtain molded products with excellent laser marking properties, and is widely used as a molding material for various office automation equipment, electrical and electronic parts, automobile parts, etc. It is possible.

[Brief description of the drawings]

[Figure 1] Schematic of chemical resistance test

[Fig. 2] Schematic diagram of sound deadening test

FIG. 3 is a schematic sectional view of a sound deadening test.

[Explanation of symbols]

 1 Test piece 2 Crack generation point X Distance to critical point of crack generation 3 ABS resin 4 Spring

Claims (2)

[Claims] 1. A polymer (B) mainly composed of 25 to 70% by weight of a polyester resin (A) and a rubber-like graft copolymer.
A thermoplastic resin composition comprising 100 parts by weight of a resin mixture consisting of 30 to 75% by weight and 3 to 15 parts by weight of a multiphase structural thermoplastic resin (C) containing a polyolefin (co) polymer. 2. A thermoplastic resin (C) having a multiphase structure, comprising a polyolefin-based (co) polymer, having a particle size of 0.001 to 1.
The thermoplastic resin composition according to claim 1, which comprises 5 to 95% by weight of 0 μm dispersed particles and 95 to 5% by weight of a vinyl-based copolymer comprising at least one vinyl monomer.