JPS61204238A - Surface-treatment of polyolefin resin molded article - Google Patents

Abstract

PURPOSE:To improve the primary adhesivity and the secondary adhesivity in the painting and bonding, etc., of the surface of a molded polyolefin resin, remarkably, by molding a polyolefin resin blended with a specific amount of a chlorinated polyolefin, and treating the surface of the molded article with plasma. CONSTITUTION:The surface of a molded article of a composition obtained by blending (A) 100pts.wt. of a polyolefin resin with (B) 0.5-30pts. of a chlorinated polyolefin (preferably having a chlorine content of 1-45wt%) is treated with plasma, usually under 0.1-3.0 Torr pressure for preferably 3sec-20min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method for completely improving the surface properties of a molded article by plasma treating a molded article made of a polyolefin resin containing a chlorinated polyolefin.

BACKGROUND OF THE INVENTION Polyolefin resins are inherently non-polar, making it difficult to adhere or paint them, and their uses have been limited. For this reason, it is known that polyolefin resin molded bodies are treated with low-temperature plasma to improve their adhesion to paints and adhesives, but in order to have practical coating film performance and adhesive performance, However, simple low-temperature plasma treatment was insufficient.

As a method for improving the paintability and adhesion of such polyolefin resins, for example, there is a method in which a propylene polymer is filled with inorganic fine powder and the surface of a molded product of a nine-composite resin is treated with low-temperature plasma (Japanese Patent Laid-Open No. 56-82826). (No. 57-207625), a method of plasma treating the surface of a composite material molded article made by blending Merck and ethylene propylene rubber with a propylene resin (No. 1982-207625), a method of plasma treating the surface of a composite material molded article made of a propylene resin blended with Merck and ethylene propylene rubber (Japanese Patent Publication No. 57-207625), a method consisting of a polyolefin resin containing a fatty acid metal salt. Surface treatment method of plasma treating the surface of a molded body (4! Open% 58-1792
39) and a method of plasma treating the surface of a molded article made of a polyolefin resin containing a hindered amine (Patent Publication No. 58-17924.0).

Although the above proposal improves the paintability of polyolefin resin moldings to a certain extent, it is not satisfactory, and problems such as the formation of blisters (glister) occur especially with respect to secondary adhesion such as hot water resistance. It was left behind.

An object of the present invention is to solve the above-mentioned problems and provide a surface treatment method that completely improves surface properties such as paintability and adhesion of the surface of a polyolefin molded article, particularly secondary adhesion.

The present inventors have carried out various studies to achieve the object of the present invention. By plasma treating the surface of a polyolefin resin molded article containing chlorinated polyolefin, the present inventors have improved the adhesion to paints and adhesives. The present invention has been completed based on the discovery that this can be significantly improved.

That is, the present invention provides a method for surface treatment of a polyolefin resin molded article, characterized in that the surface of a molded article containing 0.5 to 30 parts by weight of chlorinated polyolefin per 100 parts by weight of a polyolefin resin is subjected to plasma treatment. It's a method.

The polyolefin resin in the present invention is a homopolymer of α-olefin such as ethylene or propylene, butene-1, pentene-1, hexene-1,4-methylpentene-1, a copolymer of ethylene and α-olefin, or A copolymer of two or more of these a-olefins,
Alternatively, ethylene or a copolymer with a vinyl ester, an unsaturated carboxylic acid, or a derivative thereof having these α-olefins as a main component can be mentioned. Included here are copolymers and random, block or graft copolymers.

Moreover, two or more types of these resins can be used in combination.

Among the polyolefin resins mentioned above, polymers containing propylene as a main component, such as polypropylene and random t- or block copolymers prepared by copolymerizing propylene with ethylene or other a-olefins, are preferred. Moreover, elastomers such as ethylene-propylene rubber and ethylene-propylene-diene copolymer can be mixed with the polyolefin resin. Furthermore, part or all of the polyolefin resin can be modified with an unsaturated carboxylic acid or a derivative thereof.

Examples of the chlorinated polyolefin in the present invention include those obtained by chlorinating the above-mentioned polyolefin resins. Among these chlorinated polyolefins, chlorinated products such as homopolypropylene, propylene-ethylene copolymer,
Chlorinated products such as low, medium, and high density polyethylene, linear low density polyethylene, etc. Ethylene/propylene = 80/20~2
Chlorinated rubbers such as 0/80% by weight ethylene-propylene rubber and ethylene-propylene-diene copolymer are preferred. The chlorine content of these chlorinated polyolefins is preferably 1 to 45% by weight.

In the molded article of the present invention, 0.5 to 30 parts by weight, preferably 5 to 30'M parts, of a chlorinated polyolefin is blended with 100 parts by weight of a polyolefin resin.

If the amount of chlorinated podioolefin is less than 0.5 parts by weight, the object of the present invention cannot be achieved, while if it exceeds 30 parts by weight, no further effect can be expected and it is uneconomical.

In the present invention, in addition to the above-mentioned components, inorganic fillers such as Merck, mica, calcium carbonate, glass fiber, carbon fiber, and crystalline calcium silicate, antioxidants, ultraviolet absorbers, and dispersants are used as necessary. , a coloring agent, etc. may be added within a range that does not impair the effects of the present invention.

The method for blending the chlorinated polyolefin with the polyolefin resin is not particularly limited, but it is usually melt-mixed using a single-screw or twin-screw press ratio machine, hot roll, or mixer.

Further, the molded body may be molded by any method such as injection molding, extrusion molding, press molding, blow molding, etc. Note that the molded body may be subjected to steam cleaning using a solvent such as trichloroethane in order to remove dirt and the like from the surface thereof.

The plasma treatment in the present invention may be performed by high-frequency discharge or microwave discharge, and a reactive plasma gas such as oxygen, gas, or air, or a non-reactive plasma gas such as argon or helium is generated, and this is applied to the molded product. This is done by contacting the surface of the

Processing conditions are not particularly limited, but usually the pressure is 0.1
~3.0 torr, processing time is 3 seconds to 20 minutes.

According to the method of the present invention, primary adhesion and secondary adhesion in coating, adhesion, etc. on the surface of a molded product can be significantly improved compared to already proposed surface treatment methods for polyolefin resin molded products.

Due to the above-mentioned excellent properties, the method of the present invention can be applied in various fields such as automobile parts, home appliance parts, and daily necessities.

Example Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that % and parts in the examples are based on weight, and the experimental conditions were as follows.

The test piece was molded into a multi-plate shape by injection molding.

Plasma treatment is performed using a high frequency discharge (13,56MHz) plasma treatment equipment and microwave frequency @ (2450MI+
2) In a plasma processing device, use air at a pressure of 1 Ot.
orr, and the test piece was processed for 60 seconds at an output of 500W.

In the coating film performance test, urethane paint was spray applied to a plasma-treated test piece, and after drying, the M film was tested at 18%.
0@Peel strength was measured. In addition, in the hot water immersion test, the test piece after drying the paint was immersed in 40C hot water for 10 days, and then the coating surface was observed. was marked as ×.

Examples 1 to 4, Comparative Examples 1 to 6 Homopolypropylene (MI = 15,9710 minutes, hereinafter P
P-1), ethylene-propylene block copolymer (ethylene content = 7%, nI = 9II/10 min, hereinafter referred to as PP-2), ethylene-propylene block copolymer
1 coalescence (engine f'7 content; 7%, MI=l!Ml/10
minutes, hereinafter referred to as pp-35), ethylene propylene rubber (
Ethylene content = 70%, Mooney viscosity ML, +8127
C=52, hereinafter referred to as EPR) and ethylene-propylene-diene copolymer (ethylene content = 65%, third component: ethylidene norbornene, Mooney viscosity ML, +8
+27c=50. For 100 parts by weight of each polyolefin (hereinafter referred to as IEPDM), chlorinated polypropylene [
Super Chron SO 6 (product name), chlorine content = 67%, hereinafter referred to as chlorinated pp], manufactured by Sanyo Kokusaku Palf Co., Ltd., chlorinated polyethylene [manufactured by Osaka 1, Daiso Raku MR1
04 (product name), chlorine content = 40%, hereinafter chlorinated PK-
1], chlorinated polyethylene [manufactured by Showa Denko, 3o
IA (product name), chlorine content = 30%, hereinafter chlorinated PE
-2], chlorinated KPDM (chlorine content = 5%,
Each chlorinated polyolefin (manufacturing method is as follows), Merck (average particle size: 2.5μ), mica (average particle size: 40μ)
, fibrous crystalline calcium silicate (average particle size: 9μ, hereinafter referred to as calcium silicate), calcium stearate, and hindered amine (manufactured by Sankyo Co., Ltd., Sanol LS770 (trade name)) were blended in the proportions shown in Table 1. The resulting composition was molded into a test piece by injection molding.

The obtained test piece was subjected to plasma treatment and a coating film performance test was conducted, and the results are shown in Table 1.

EPDM (ethylene content = 65%, third component = ethylidene norbornene, Mooney viscosity ML, +4+z7C=s
5 parts by weight of crystalline high-density polyethylene powder was mixed with 100 parts by weight of pulverized a) at a low temperature. This powder 1509 was placed in a glass container with an internal volume of 21, and 0.1 g of a nonionic emulsifier and water Ie were added thereto, stirred and heated, and the temperature was adjusted to about 80C. Apply 15 I of chlorine gas to this thread.
The mixture was introduced at a rate of 1/min and reacted for 2 hours.

During the reaction, the glass container was illuminated from the outside with a fluorescent lamp. After the reaction was completed, it was washed with warm water, dried under reduced pressure with SaC, and chlorinated KPDM with a chlorine content of 15% by weight was added to the diameter ratio.

Claims (1)

[Claims] A method for surface treatment of a polyolefin resin molded article, which comprises subjecting the surface of a molded article prepared by blending 0.5 to 30 parts by weight of a chlorinated polyolefin to 100 parts by weight of a polyolefin resin to plasma treatment.