JPH06116472A - Thermoplastic resin composition excellent in coatability - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin composition improved in coatability without detriment to the excellent heat resistance, moldability, impact resistance, etc., of a starting resin, particularly heat resistance. CONSTITUTION:The composition is prepared by mixing 100 pts.wt. rubber- reinforced thermoplastic resin with 1-20 pts.wt. polyether-ester type or polyester- ester type polyester elastomer containing 20-60wt.% polybutylene terephthalate as a hard segment component and containing 40-80wt.% polytetramethylene glycol or aliphatic fatty acid polyester as a soft segment component. By mixing the specified polyester elastomer with the rubber-reinforced thermoplastic resin in the specified ratio, the coatability can markedly by improved without detriment to the heat resistance, impact resistance and moldability.

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, and more particularly to a thermoplastic resin composition having a good balance of properties such as impact resistance, moldability and heat resistance and having good coatability.

[0002]

2. Description of the Related Art Thermoplastic resins such as ABS resin, AAS resin and AES resin have been widely used as molding raw materials in various fields since they are excellent in impact resistance, moldability and heat resistance. Therefore, in order to improve the heat resistance of these thermoplastic resins, a method of substituting a part or all of styrene constituting the resin with α-methylstyrene, or a method of separately copolymerizing a maleimide compound is adopted. Has been done.

[0003]

However, these thermoplastic resins have the drawback that they are easily dissolved and swelled in organic solvents such as aromatic hydrocarbons and aliphatic hydrocarbons.
For this reason, when coating a molded product made of these thermoplastic resins, the molded product is dissolved and swelled by an organic solvent such as thinner used to dilute the paint, and the molded product is caused by residual stress. Stress cracking or crazing occurred on the surface, which was a cause of significantly impairing the appearance of the product.

Further, the thermoplastic resin having the above-mentioned formulation for improving heat resistance has been widely used for automobile interior parts, OA equipment parts, home electric appliance parts, etc., but it is still inferior in terms of coatability. As a result, defects such as suction, cracks, pinholes and poor adhesion of the coating film have occurred on the coated surface of the product.

The present invention solves the above-mentioned problems of the prior art, has good properties such as impact resistance, moldability, and heat resistance, and also has an excellent balance of properties, and has a significantly improved paintability. An object is to provide a resin composition.

[0006]

The thermoplastic resin composition of the present invention comprises 2 parts of polybutylene terephthalate as a hard segment with respect to 100 parts by weight of a rubber-reinforced thermoplastic resin.
0 to 60% by weight, containing 40% polytetramethylene glycol or fatty acid polyester as a soft segment
Polyester Ester Type or Polyester Ester Type Polyester Elastomer Containing Up to 80% by Weight 1
It is characterized by being mixed in an amount of up to 20 parts by weight.

The present invention will be described in detail below.

In the present invention, the rubber-reinforced thermoplastic resin is a rubber component: 30 to 70 parts by weight Aromatic vinyl compound: 5 to 70 parts by weight Acrylonitrile: 10 to 30 parts by weight Other copolymerizable monomer: 0 The graft copolymer is composed of ˜30 parts by weight and, if necessary, is mixed with other copolymer.

Here, as the rubber component of the graft copolymer, one kind or two or more kinds of polybutadiene, styrene-butadiene rubber, acrylic rubber, ethylene propylene non-conjugated diene copolymer (EPDM) rubber, crosslinked acrylate rubber and the like can be used. Is mentioned. The diolefins contained in EPDM include dicyclopentadiene and 1,4-
Hexadiene, 1,4-heptadiene, 1,5-cyclooctadiene, 6-methyl-1,5-heptadiene, 1
1-ethyl-1,11-tridecadiene, 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 2,5-norbornadiene, 2-methyl-2,5-
Norbornadiene, methyltetrahydroindene, limonene and the like can be mentioned.

Examples of the aromatic vinyl compound include styrene and α-methylstyrene. Other copolymerizable monomers include acryl such as methyl acrylate, ethyl acrylate and butyl acrylate. Acid ester monomer, methacrylic acid ester monomer such as methyl methacrylic acid ester, ethyl methacrylic acid ester, vinyl carboxylic acid monomer such as acrylic acid and methacrylic acid, acrylic acid amide, methacrylic acid amide, acenaphthylene, N- Vinyl monomers such as vinylcarbazole, N-alkyl-substituted maleimide, and N-aromatic-substituted maleimide are mentioned.

The graft copolymer is produced by carrying out a graft copolymerization using the above-mentioned components in a conventional manner.

On the other hand, other copolymers that can be blended with such a graft copolymer include those containing an aromatic vinyl compound, acrylonitrile, and, if necessary, other monomers copolymerizable therewith. It is preferable that the blending ratio is 10 to 80% by weight of the aromatic vinyl compound, 15 to 50% by weight of acrylonitrile, and 0 to 40% by weight of the other monomer copolymerizable with them. The copolymer having such a composition is extremely effective in improving the heat resistance of the product. The vinyl aromatic compounds and the monomers copolymerizable with them may be the same as those mentioned above.

Such a copolymer is synthesized by polymerizing the above-mentioned respective components, but the polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization and the like are adopted.

It is preferable to use, as a rubber-reinforced thermoplastic resin, a mixture of 20 to 85 parts by weight of such a copolymer with 15 to 80 parts by weight of the graft copolymer.

The polyester elastomer used in the present invention is a block copolymer composed of polybutylene terephthalate, which is a hard segment of polyester, and polytetramethylene glycol or an aliphatic polyester, which is a soft segment of polyether or polyester. However, the physical properties of this copolymer are significantly changed by changing the constituent components of each segment, the ratio of the segments to each other, and the molecular weights and types of the polyether and polyester.

Polyester elastomers are prepared, for example, by using polytetramethylene glycol or an aliphatic polyester, 1,4-butanediol and dimethyl terephthalate in the presence of a small amount of diamine, and using a titanium-based catalyst.
It can be obtained by removing methanol while heating and stirring for about 2 hours under the condition of 50 ° C./0.3 mmHg.

In the present invention, the proportion of polybutylene terephthalate as the hard segment in the polyester elastomer is 20 to 60% by weight, and the proportion of polytetramethylene glycol or fatty acid polyester as the soft segment is 40 to 80% by weight. When the hard segment is less than 20% by weight and the soft segment exceeds 80% by weight, the mechanical properties such as tensile strength, bending strength and bending elastic modulus are largely deteriorated, and the hard segment exceeds 60% by weight and the soft segment is 40% by weight. If it is less than%, the effect of improving paintability is insufficient.

In the thermoplastic resin composition of the present invention, 1 to 20 parts by weight of the above polyester elastomer is mixed with 100 parts by weight of the rubber-reinforced thermoplastic resin. If the blending amount of this polyester elastomer is less than 1 part by weight, sufficient effect of improving coatability cannot be obtained, and if it exceeds 20% by weight, heat resistance, moldability and the like are impaired.

In the thermoplastic resin composition of the present invention, the above graft copolymer and, if necessary, the above copolymer and the above polyester elastomer are blended in a predetermined ratio, and further, if necessary, other thermoplastic resin or the like. It can be easily obtained by kneading using a Banbury mixer, an extruder, a roll mill or the like.

The thermoplastic resin composition of the present invention may contain other additives such as a lubricant, an antioxidant, a flame retardant and a coloring agent, if necessary.

The thermoplastic resin composition of the present invention can be used, for example, in injection molding, hollow molding, extrusion molding, compression molding, roll processing,
The product is molded by a known method such as stretching, and is coated according to a conventional method to give a product.

[0022]

[Function] By blending a specific polyester elastomer with a rubber-reinforced thermoplastic resin in a specific ratio, heat resistance,
It is possible to significantly improve paintability while sufficiently maintaining these properties without impairing impact resistance and moldability.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.
In the following, "part" means "part by weight".

The following were used as the polyester elastomer.

Polyester elastomer B-1: Polybutylene terephthalate: 40% by weight Polytetramethylene adipate: 60% by weight Polyester elastomer B-2: Polybutylene terephthalate: 70% by weight Polytetramethylene adipate: 30% by weight Synthesis Example 1 (ABS Synthesis of Graft Copolymer C-1) An ABS copolymer was synthesized by an emulsion polymerization method with the following composition.

[Compounding] Styrene (ST) 55 parts Acrylonitrile (AN) 25 parts Polybutadiene latex (solid content) 20 parts Disproportionated potassium rosinate 1 part Potassium hydroxide 0.03 parts Tertiary decyl mercaptan (t-DM) ) 0.1 part cumene hydroperoxide 0.3 part ferrous sulfate 0.007 part sodium pyrophosphate 0.1 part crystalline glucose 0.3 part distilled water 190 parts distilled water in an autoclave, disproportionated potassium rosinate, After charging potassium hydroxide and polybutadiene latex (solid content) and heating to 60 ° C, ferrous sulfate, sodium pyrophosphate and crystalline glucose were added, and ST, AN, t-DM and cumene were kept at 60 ° C. Hydroperoxide was continuously added over 2 hours, then the temperature was raised to 70 ° C and kept for 1 hour. To complete the. An antioxidant was added to the ABS latex obtained by the above reaction, then coagulated with sulfuric acid, thoroughly washed with water, and dried to obtain an ABS graft copolymer C-1.

Synthesis Example 2 (ABS Graft Copolymer C-2
Synthesis) The same procedure as in Synthesis Example 1 was repeated except that the styrene content was 35 parts, the acrylonitrile content was 15 parts, and the polybutadiene latex (solid content) content was 50 parts. Got 2.

Synthesis Example 3 (AES Graft Copolymer C-3
Synthesis of) 50 parts by weight of ethylene / propylene / non-conjugated diene copolymer rubber latex (ethylene: propylene = 75: 25 (weight ratio)) with a gel content of 65% by weight, 70 parts by weight of an aromatic vinyl compound % And vinyl cyanide compound 3
AES graft copolymer C-3 was obtained in the same manner as in Synthesis Example 1 except that the total amount of 50 parts of the vinyl monomer mixture consisting of 0% by weight was 100 parts.

Synthesis Example 4 (AAS Graft Copolymer C-4
Synthesis of) AAS graft copolymer C- in the same manner as in Synthesis Example 1 except that 15 parts of acrylonitrile and 35 parts of styrene were reacted in the presence of 50 parts of polybutyl acrylate rubber.
Got 4.

Synthesis Example 5 (Synthesis of AS Copolymer D-1) 120 parts of water, 0.002 part of sodium alkylbenzene sulfonate, 0.5 part of polyvinyl alcohol, 0.3 part of azoisobutyl nitrile were placed in a reactor substituted with nitrogen. Then, a monomer mixture consisting of 30 parts of acrylonitrile and 70 parts of styrene was added and heated at a starting temperature of 60 ° C. for 5 hours, then
The temperature was raised to 0 ° C., and after reacting for 4 hours, the polymer was taken out. The conversion rate was 98%.

Synthesis Example 6 (Synthesis of AMS Copolymer D-2) 200 parts of water, 2.0 parts of sodium alkylbenzene sulfonate and 0.3 part of potassium persulfate were placed in a reactor purged with nitrogen and heated to 73 ° C. Then, 65 parts of α-methylstyrene, 20 parts of acrylonitrile, and 15 parts of styrene, and 0.4 part of t-dodecyl mercaptan were continuously added over 100 minutes, and emulsion polymerization was carried out for 3 hours. The conversion rate was 98%.

Synthesis Example 7 (AS-N / PMI Copolymer E-
Synthesis of 1) A polymer was obtained in the same manner as in Synthesis Example 5, except that the monomer mixture was 65 parts of α-methylstyrene, 15 parts of N-phenylmaleimide, and 20 parts of acrylonitrile.
The conversion rate was 95%.

Synthetic Example 8 (Synthesis of MMASAN Copolymer F-1) Except that the monomer mixture was 50 parts of methyl methacrylate, 20 parts of styrene and 30 parts of acrylonitrile.
A polymer was obtained in the same manner as in Synthesis Example 6. Conversion rate is 98%
Met.

Examples 1 to 7 and Comparative Examples 1 to 3 The copolymers and polyester elastomers were mixed in the formulations shown in Table 2 and molded under the following conditions.

Molding conditions (test piece molding conditions) Molding machine: "FS-55SE (2oz)" manufactured by Nissei Jushi Kogyo Molding temperature Nozzle: 240 ° C front part: 240 ° C middle part: 220 ° C rear part: 200 ° C resin temperature: 245 ° C. Mold temperature: 50 ° C. EBS-WAX was added as a lubricant in the mixed raw material to 1.
0 parts were compounded.

Various properties of the obtained molded product were tested,
The results are shown in Table 2. The characteristic test was performed under the following conditions and methods.

Izod impact value (kg · cm / cm): ASTM
(D256) Notched Izod, 23 ° C. Melt flow rate (g / 10 min): ASTM (D),
200 ℃, 5kg Heat deformation temperature (℃): ASTM (D64
8) Bending elasticity (kg / cm ² ): ASTM (D79
0) Further, coating was performed under the following coating conditions, and the appearance after coating was observed, and evaluation was made as follows: = very good, ◯ = good, x = bad. In addition, the adhesion was tested by the eye contact test, and the results are also shown in Table 2.

Coating conditions (all manufactured by Kansai Paint) Paint (main agent): Undercoat = Soflex 5100 Topcoat = Soflex 5500 Curing agent: Soflex standard curing agent Thinner: Soflex standard thinner (compounding ratio, etc.)

[0039]

[Table 1]

(Coating process) Isopropyl alcohol wipe Undercoating interval (normal temperature, 10 minutes) Topcoating setting (normal temperature, 10 minutes) Drying

[0041]

[Table 2]

As is clear from Table 2, according to the present invention, there is provided a thermoplastic resin composition having excellent impact resistance, heat resistance, moldability and mechanical properties, and also having excellent coatability.

On the other hand, in Comparative Example 1 in which the amount of the polyester elastomer compounded was small, the coatability was poor and, conversely,
Comparative Example 2 containing a large amount of the polyester elastomer is inferior in heat resistance and flexural modulus, and Comparative Example 3 containing a large amount of the hard segment of the polyester elastomer is inferior in coatability, both of which are not preferable.

[0044]

As described above in detail, according to the thermoplastic resin composition of the present invention, various properties such as impact resistance, heat resistance, moldability and various other mechanical properties are excellent, and the coating property is excellent. A significantly improved thermoplastic resin composition is provided.

The thermoplastic resin composition of the present invention is extremely useful as a molding raw material for automobile interior parts, OA equipment parts, home electric appliance parts and the like, and can provide a high quality product having a good coated surface. To be done.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 67:02)

Claims (1)

[Claims] 1. Polybutylene terephthalate as a hard segment is contained in an amount of 20 to 60% by weight with respect to 100 parts by weight of a rubber-reinforced thermoplastic resin, and polytetramethylene glycol or a fatty acid polyester is used as a soft segment.
A thermoplastic resin composition having an excellent coating property, which is obtained by blending 1 to 20 parts by weight of a polyether-ester type or polyester-ester type polyester elastomer containing 0 to 80% by weight.