JPH06248135A - Thermoplastic resin composition excellent in weatherability - Google Patents

Abstract

PURPOSE: To obtain styrene based thermoplastic resin compositions which have solved the problems of ACS resins and have excellent chemical properties and weatherability and, at the same time, difficulty in causing laminar peeling compared to the conventional ones.

CONSTITUTION: A styrene based thermoplastic resin composition comprises (A) 50-85 wt.% styrene based polymer, (B) 10-35 wt.% chlorinated polyethylene, (C) 5-35 wt.% modified ethylene-propylene based rubber and (D) 0-10 wt.% vinyl based graft copolymer.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin, and more particularly to a styrene-based thermoplastic resin composition having excellent weather resistance and excellent mechanical properties such as impact strength. Is.

[0002]

2. Description of the Related Art ABS resin is a copolymer resin of acrylonitrile, butadiene and styrene, and generally has excellent physical properties such as impact resistance and tensile property, chemical resistance, molding processability, etc. This resin is widely used in products and various office equipment.

However, the ABS resin is apt to undergo an oxidation reaction due to ultraviolet rays or oxygen due to the double bond of butadiene rubber, which is one of its components, and thus discoloration and deterioration of physical properties are serious, and therefore weather resistance is required. There was a limit in applying it to electronic products and outdoor products.

In order to solve such problems, US Pat. Nos. 3,886,233 and 4,007,2 have been proposed.
As disclosed in Japanese Patent Publication No. 34, etc., ethylene-propylene rubber (hereinafter referred to as "EPR") or ethylene-propylene-diene rubber (hereinafter referred to as "EPDM") having no or almost no double bond in place of butadiene rubber. Called)
Is used as an impact reinforcing material by graft polymerization of SAN, or as described in US Pat. No. 4,528,328, a high impact resistance and weather resistance is obtained by using a graft polymer of acrylic rubber. There is a method to obtain.

However, the above-mentioned graft polymer has the drawbacks that it has a very low fluidity, the processing conditions are limited, and a complicated manufacturing process is required.

On the other hand, Japanese Patent Publication No. 39-17057,
No. 41-6351 discloses an ACS (acrylonitrile-chlorinated polyethylene-styrene) resin produced by polymerizing or blending chlorinated polyethylene with an acrylonitrile-styrene copolymer instead of butadiene rubber. Although it has excellent heat resistance and weather resistance, it has a drawback that mechanical properties such as impact resistance are somewhat inferior.

In order to solve such disadvantages of the ACS resin, Japanese Patent Publication No. 48-44933 discloses a chlorinated polyethylene (hereinafter referred to as "CPE") and a small amount of EPR or EPDM as an impact reinforcement of a styrene resin. Although the mechanical properties such as impact resistance have been improved by using it, this technique has a problem that impact strength improving effect is low and delamination occurs.

In order to solve the above-mentioned problems, EP 37609 and US Pat. Nos. 4,341,884 and 4,468,487 disclose EP in the above composition.
Crystalline CPE is used with increasing amounts of DM.

However, this method also has a limit in improving the mechanical properties and is not effective in preventing delamination.

[0010]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems of the ACS resin, has excellent mechanical properties as compared with existing thermoplastic resins, and has delamination. An object of the present invention is to provide a resin composition having a low occurrence rate of phenomena and excellent weather resistance.

[0011]

Means and Actions for Solving the Problems As a result of intensive studies for the above purpose, the present inventors have found that styrene resin and CPE, modified ethylene-propylene rubber and vinyl impact reinforcement are suitable. It was clarified that the above-mentioned object can be achieved by adjusting and using it at various ratios.

The present invention is characterized by having the following composition.

(A) Aromatic vinyl monomer 60-85w
50% to 85% by weight of a styrene polymer obtained by mixing 40% to 15% by weight of a vinyl cyanide monomer and 0% to 40% by weight of another vinyl monomer that can be polymerized with t%, and polymerized (B) chlorine CPE10-35w with a content of 20-40wt%
t%; (C) Reactive monomer having 0 to 2 parts of organic peroxide and 100 to 100 parts by weight of ethylene-propylene rubber (hereinafter abbreviated as "part") and a carboxyl group or an anhydrous carboxyl group. Modified ethylene-propylene rubber 5 to 35 wt% produced by melt-kneading 5 to 6 parts; and (D) vinyl graft copolymer 0 to 10 wt% are blended and melt-kneaded to produce.

The present invention will be described in more detail below.

As the vinyl-based copolymer constituting component of the component (A) of the present invention, the aromatic vinyl monomer and vinyl cyanide monomer listed above can be used, and they can be polymerized. Examples of the vinyl monomer include (meth) acrylic acid ester monomers such as methyl, ethyl, propyl and n-butyl of acrylic acid and methacrylic acid, maleimide, N-
Maleimides such as methylmaleimide, N-phenylmaleimide, etc., acrylamide.

As the method for producing the constituent component (A), any of known polymerization methods such as emulsion polymerization, suspension polymerization, bulk polymerization and continuous polymerization can be used.

The component (B) of the composition, CPE, can be produced by chlorinating polyethylene through a solution, suspension or gas phase reaction, and the production method is described in US Pat.
Those disclosed in Japanese Patent No. 935,181 and Japanese Patent No. 4,197,386 can be used.

The chlorine content of CPE is 20 to 40 wt% in consideration of the compatibility with the constituent component (C) and the impact reinforcing effect.
% Is appropriate. A suitable composition ratio of the component (B) is 10 to 35 wt% with respect to the entire composition, and preferably 13 to 25 wt%.

When the CPE is less than 10 wt% with respect to the entire composition, the tensile strength, hardness and heat resistance are improved, but the elongation and impact resistance sharply decrease, while when it exceeds 35 wt%, the impact resistance is increased. Although the characteristics are excellent, toxic gas is generated at the time of molding, and the tensile strength, hardness, and weather resistance are deteriorated, which causes a problem that it is not suitable for practical use.

As the ethylene-propylene rubber constituting the modified ethylene-propylene rubber as the constituent component (C) of the present composition, ethylene-propylene rubber (hereinafter referred to as "EP
R ") and ethylene-propylene-diene rubber (hereinafter referred to as EPDM") can be used. The diene component of EPDM in this is 1,4-hexadiene,
Dicyclopentadiene, 5-vinyl nobonene, 2,5-
Ethylidene nobonene or the like can be used, and the composition thereof can be 2 to 8 parts based on 100 parts of EPDM.

Examples of the organic peroxide used for the production of the component (C) include diisopropylbenzene hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide and di-t-butyldioxide. Peroxyphthalate, succinic acid peroxide, t-butyl peroxybenzoate, t-
Butyl peroxymaleic acid, methyl ethyl ketone peroxide, cyclohexanone peroxide and the like can be used. Among them, it is preferable to use dicumyl peroxide in consideration of reactivity and processability.

Maleic acid, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid ester and the like can be used as the reactive monomer having a carboxyl group or a carboxyl anhydride group used for the production of the component (C). The use of maleic anhydride is preferred.

When more than 2 parts of the organic peroxide is mixed during the production of the modified ethylene-propylene rubber, the rubber property is reduced by the cross-linking reaction, the impact-reinforcing effect is lowered, and the amount of the reactive monomer is reduced. If it is less than 1.5 parts or exceeds 6 parts, the impact resistance effect is reduced. Also, the constituent component (C)
If the ratio of the modified ethylene-propylene rubber of 3 is out of the range of 5 to 35 wt% with respect to the entire resin composition, the impact reinforcing effect is insufficient.

The component (C) is produced by mixing EPR or EPDM with an organic peroxide or a reactive monomer,
It is manufactured by modifying EPR or EPDM in a melt-kneaded state using a Banbury mixer or a vent type extruder.

The main chain component (a) of the vinyl-based graft polymer which is the constituent component (D) of the present composition is an ester compound such as methylmethacrylic acid, butylmethacrylic acid or butylacrylic acid, or a carboxyl group such as vinyl acetate. Among these, it is a copolymer of a monomer containing ethylene with an olefinic monomer such as ethylene or propylene, and among them, ethylene / vinyl acetate, ethylene / ethyl acrylate and the like can be preferably used.

As the side chain component (b), a copolymer of a styrene-based monomer and a vinyl cyanide-based monomer or the like is used. Among them, a styrene-acrylonitrile copolymer is most used. desirable. In the main chain component (a), the amount of the monomer containing a carboxyl group is less than 5 wt% or 40 w
When it exceeds t%, the impact reinforcing effect is poor, and when the amount of the main chain (a) in the constituent component (D) is less than 40 wt% or exceeds 90 wt%, the impact reinforcing effect is poor.

When the ratio of the constituent component (D) exceeds 10 wt% with respect to the entire composition, mechanical properties such as tensile strength are deteriorated.

The method for producing the present resin composition is not particularly limited. For example, (A) vinyl-based copolymer and (B) CP
E, (C) modified ethylene-propylene rubber and (D)
After the vinyl-based graft polymer is mixed, it can be produced by a usual method using a Banbury mixer or a vent type extruder.

As described above, the thermoplastic resin composition of the present invention differs from the conventional ones by mechanically adding an ethylene-propylene rubber modified with a reactive monomer having a carboxyl group. The physical properties are improved, the surface delamination phenomenon is reduced, and the weather resistance is improved. It is speculated that this is due to the favorable interaction between the modified ethylene-propylene rubber and CPE and other components.

As can be seen from FIGS. 1, 2 and 3, when the modified ethylene-propylene rubber is used, the degree of dispersion of the rubber particles becomes better as compared with the case where EPR or EPDM is used. Interaction with matrix resin is increasing.

If necessary, flame retardants, lubricants, heat stabilizers, light stabilizers, pigments, etc. may be added to the above thermoplastic resin composition for use.

[0032]

EXAMPLES Examples of the present invention will be described below.

Production Example (1) Polymer (A) (A) -1: Produced by suspension polymerization by adding 730 g of styrene, 270 g of acrylonitrile and 5 g of t-dodecyl mercaptan to a reactor.

(A) -2: 710 g of α-methylstyrene, 290 g of acrylonitrile and 5 g of t-dodecyl mercaptan were placed in a reactor and emulsion-polymerized.

(2) Polymer (B) The following 3 types of CPE were used.

(B) -1: TYRIN 3615 (CPE of Dow Chemical Product of the United States, chlorine content 36 wt%) (B) -2: DAISOLAC J-230 (CPE of Nihon Taisho product, chlorine content 30 wt%) (B) -3: DAISOLAC MR104 (Nippon Taisho CPE, chlorine content 40 wt%) (3) Polymer (C) EPR (KEP020P manufactured by Kotoko EP Rubber, Korea) or EPDM (KEP570 manufactured by Koto EP Rubber, Korea)
P), maleic anhydride (hereinafter referred to as “MA”), and dicumyl peroxide (hereinafter referred to as “DCP”) are shown in Table 1.
After mixing at the ratio shown in, L / D = 34, φ = 40 m
pelletized polymer (C) -using a twin screw extruder
1- (C) -6 were manufactured. At this time, the cylinder temperature is 150 to 190 ° C, and the screw rotation speed is 400 rpm.
Set to.

[0037]

[Table 1]

Among the above results, the grafted MA
The content of was calculated by reprecipitating the produced pellet with a toluene / methanol solution and then measuring the area of the characteristic band (1785 cm ⁻¹ ) of MA with an infrared spectroscope. Among the above results, the gel content was calculated by measuring the weight of the residual gel by the Soxhlet distillation method (distillation for 8 hours).

(4) Polymer (D) MODIPER A6400 ((D) -1) manufactured by NOF CORPORATION,
A5400 ((D) -2) was used, and the symbols and compositions of each component are as shown in Table 2 below.

[0040]

[Table 2]

Examples 1 to 5 and Comparative Examples 1 to 4 Examples 1 to 5 and Comparative Examples 1 to 4 are polymers (A),
After mixing (B) and (C) at a constant ratio as shown in Table 4 below, pellets were produced using a twin-screw extruder with L / D = 34 and φ = 40 mm, and then the pellets were injected. Molded to prepare a test piece for measuring mechanical properties and weather resistance, and shown in Table 3 below.
The test method and test conditions as described above were used for measurement. The results are shown in Table 4.

The cylinder temperature at this time is 180 to 210.
It was set to ° C.

[0043]

[Table 3]

[0044]

[Table 4]

Based on the results in Table 4 above, MA modified EPR or E
It can be seen that when PDM is used, mechanical properties such as tensile strength and impact strength are improved to a greater extent than when EPR and EPDM are used, and the surface releasability is improved. However,
Modified EP with MA content less than 1.5 parts or more than 6 parts
When R is used (Comparative Examples 1 and 2), the elongation and impact strength are rather reduced, and the effect of improving surface peeling is also insufficient.

Examples 6 and 7 and Comparative Examples 5 to 12 In Examples 6 and 7 and Comparative Examples 5 to 12, changes in mechanical properties and weather resistance depending on the contents of CPE and modified EPR were measured. The results are shown in Table 5 below. Extrusion, injection and property measurement methods are the same as in Examples 1-5.

[0047]

[Table 5]

As can be seen from the results in Table 5 above, CP
When the E-modified EPR is used alone, the tensile strength, the elongation and the impact strength are improved more than when the E-modified EPR is used alone. In the case of Comparative Example 5 in which the content of the polymer (B) (CPE) is less than 10 wt% or less, the impact strength is very low, and in the case of Comparative Example 6 in which CPE is used excessively, the tensile strength and the weather resistance are It will be very low.

In Examples 6 and 7 and Comparative Examples 5 to 10, 0.2 parts by weight of a light stabilizer was added together with an antioxidant.

Examples 8 to 13 and Comparative Examples 13 to 15 In Examples 8 to 13 and Comparative Examples 13 to 15, a vinyl-based graft polymerizing agent was added as an impact reinforcing material, and the physical properties and surface releasability were measured. The results are shown in Table 6 below. The extrusion, injection and physical property measurement methods are the same as those in Examples 1 to 5 above.

[0051]

[Table 6]

From the results shown in Table 6 above, when compared with the case where EVA was added, the cases where the polymers (D) -1 and (D) -2 were added exhibited better physical properties, and (D) -2
Than (D) -1 is more effective in improving the physical properties,
It can be seen that the effect of improving the physical properties decreases when both (D) -1 and (D) -2 exceed 10 wt%.

[0053]

As confirmed by the above Examples and Comparative Examples, in the composition of the present invention, it is possible to omit the polymerization step, while having excellent mechanical properties and weather resistance, and at the same time, delaminate the surface. Sex is greatly improved.

[Brief description of drawings]

FIG. 1 shows the morphology of a fracture surface when ethylene-propylene rubber (EPR) is used as the ethylene-propylene rubber in the constituent components of the present invention (Comparative Example 3).
It is an electron micrograph (SEM) of a magnification,

FIG. 2 is an ethylene-propylene-diene rubber (EPD) as an ethylene-propylene rubber in the constituent components of the present invention.
(M) was used under the same conditions (Comparative Example 4), the morphology of the fracture surface was observed at a magnification of 2000 times (SE).
M),

FIG. 3 shows the morphology of a fracture surface when modified ethylene-propylene rubber is used as the ethylene-propylene rubber in the constituents of the present invention under the same conditions (Example 2).
It is an electron micrograph (SEM) at a magnification of 000.

Claims (8)

[Claims] 1. A styrene-based polymer (A) 50 to 85 wt.
%, (B) chlorinated polyethylene 10 to 35 wt%, (C) modified ethylene-propylene rubber 5 to 35 wt%
% And (D) vinyl-based graft copolymer 0 to 10 wt%, a thermoplastic resin composition. 2. The thermoplastic resin composition according to claim 1, wherein the component (B) chlorinated polyethylene has a chlorine content of 20 to 40 wt%. 3. The component (C) modified ethylene-propylene rubber is a reactive monomer 1 having 0 to 2 parts of an organic peroxide and a carboxyl group or an anhydrous carboxyl group with respect to 100 parts of ethylene-propylene rubber. The thermoplastic resin composition according to claim 1, which is produced by melt-kneading 5 to 6 parts. 4. The component (C) modified ethylene-propylene rubber is a reactive monomer having 0 to 2 parts of an organic peroxide and 100 parts of an ethylene-propylene-diene rubber and a carboxyl group or an anhydrous carboxyl group. The thermoplastic resin composition according to claim 1, which is produced by melt-kneading 1.5 to 6 parts. 5. The thermoplastic resin composition according to claim 1, wherein the component (D) vinyl-based graft copolymer has an ester compound as a main chain component. 6. The vinyl graft copolymer as the component (D) has a copolymer of a monomer having a carboxyl group and an olefin monomer as a main chain component. The thermoplastic resin composition. 7. The component (D) vinyl-based graft copolymer has a copolymer of a styrene-based monomer and a vinyl cyanide-based monomer as a side chain component. Thermoplastic resin composition. 8. The reactive monomer having a carboxyl group or a carboxyl anhydride group is one selected from maleic acid, maleic anhydride, fumaric acid, acrylic acid, and methacrylic acid ester. The thermoplastic resin composition according to claim 3 or 4.