JPS61204237A - 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 compounded with a specific amount of nucleation agent, and treating the surface of the molded article with plasma. CONSTITUTION:The surface of a molded article of a composition obtained by compounding (A) 100pts.wt. of a polyolefin resin (preferably a polymer composed mainly of propylene) with (B) 0.01-2pts. of a nucleation agent (e.g. dibenzylidene sorbitol), is treated with plasma, usually under 0.1-3.0 Torr pressure for preferably 3sec-20min.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a surface treatment method for improving the surface characteristics of a molded body by plasma treating a molded body made of a polyolefin resin containing nucleating agent t-gold. Regarding.

BACKGROUND ART Polyolefin resins are inherently non-polar, making it difficult to adhere or paint them, and their uses are 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. Low-temperature plasma treatment alone was insufficient.

As a method for improving the paintability and adhesion of such polyolefin resins, for example, a method of treating the surface of a molded product of a composite resin in which a propylene polymer is filled with inorganic fine powder with low-temperature plasma (Japanese Patent Laid-Open No. 56-82826) has been proposed. Publication], A method of plasma treating the surface of a composite material molded product made by blending Merck and ethylene propylene rubber with a propylene resin (Japanese Unexamined Patent Publication No. 57-207625), Molding made of a polyolefin resin containing a fatty acid metal salt Surface treatment method for plasma treating the surface of the body (Japanese Unexamined Patent Publication No. 58-17923
No. 9], No. 9 - Method for plasma treating the surface of a molded article made of a polyolefin resin containing doamine (
Japanese Unexamined Patent Publication No. 58-179240] has been proposed.

Problems to be Solved by the Invention Although the above proposal improves the paintability of polyolefin resin moldings to a certain extent, it is not satisfactory, and especially with regard to secondary adhesion such as hot water resistance, blistering occurs. Problems such as the occurrence of

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

Means for Solving the Problems In order to achieve all the objects of the present invention, the present inventors conducted various studies on VC, and found that by plasma treating the surface of a polyolefin resin molded body containing a nucleating agent, paint We found that the adhesion to adhesives and adhesives was significantly improved.
A friend who completed this invention.

That is, the present invention provides plasma treatment for the surface of a molded product made by blending 0.01 to 2 parts by weight of a nucleating agent with respect to 100 parts by weight of a polyolefin resin. This is a processing method.

The polyolefin resin in the present invention includes homopolymers of α-olefins such as ethylene 4L<a propylene, phthene-1, pentene-1, hexene-1,4-methylpentene-1, and copolymers of ethylene and α-olefins. Or a copolymer of two or more of these α-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 used. Here, the copolymers include random copolymers and block copolymers and graft copolymers.

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

Among the above-mentioned polyolefin resins, polymers containing propylene as a main component such as polypropylene, a random polymer made by copolymerizing propylene with ethylene or other a-olefin gold, and block copolymers are preferred. Ninth, 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.

As the nucleating agent in the present invention, metal salts of aromatic carboxylic acids or aromatic dicarboxylic acids or their alkyl-substituted derivatives, dibenzylidene lupitors, and the like can be used. Examples include the sodium or potassium salts of benzoic acid, the aluminum salts of di-para-tert-butyl-benzoic acid, the titanium or chromium salts of para-tert-butyl-benzoic acid, the aluminum salts of monophenylacetic acid, Examples include shihenzylidene rubitol and g-paramethylbenzylidene rubitol.

The molded article in the present invention has a nucleating agent of 0.01 to 2X parts, preferably 0.01 to 2X parts by weight, based on 100 parts by weight of the polyolefin resin.
．． It contains 1 to 2 parts by weight. Nucleating agent is 0.0
If it is less than 1 part by weight, the object of the present invention cannot be achieved, while if it exceeds 2 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 talc, mica, calcium carbonate, glass fiber, carbon fiber, and crystalline calcium silicate, antioxidants,
Ultraviolet absorbers, dispersants, colorants, etc. can be blended within a range that does not impair the effects of the present invention.

The method for blending the nucleating agent into the polyolefin resin is not particularly limited, but it is usually melt-mixed using a single-screw or twin-screw extruder, a hot roll, a Banbury mill, or the like.

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 generates a reactive plasma gas such as oxygen, nitrogen, or air, or a non-reactive plasma gas such as argon or helium, and applies this to the surface of the molded product. This is done by bringing it into contact with.

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

Effects of the Invention 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. I can do it.

Due to the excellent properties described above, 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.

In addition, the % machining part in the examples is based on weight, and the experimental conditions are as follows.

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

Plasma treatment is performed using high frequency discharge (13,56MH2) plasma processing equipment and microwave discharge (2450MH2)
In a plasma processing device, a pressure of 1. Otor
r, the test piece was processed for 60 seconds at an output of 500W.

In the coating film performance test, urethane paint was sprayed onto a plasma-treated test piece, and the coating film after drying was tested at 18%.
The 0° peel strength was measured. In addition, in the hot water immersion test, all test pieces after drying the paint were immersed in warm water at 40°C for 10 days, and then the coating surface was observed. No blisters were ○, some blisters were Δ, and blisters (thick) were 6! It was set as IX.

Examples 1 to 9, Comparative Examples 1 to 6 Homopolypropylene (M I = 151//10 min, hereinafter referred to as PP-1), ethylene-propylene block copolymer (ethylene content = 7%, MI = 9.9// 10 minutes, hereinafter referred to as PP-2), ethylene-propylene rubber (ethylene weight = 70%, Mooney viscosity ML 127°C =
52, hereinafter referred to as KPR1+4] and] ethylene-propylene-diene copolymer ethylene content = 65%, third component = -Z f IJ
7” Norbornene, Mooney viscosity ML, +8127°C
=50, hereinafter referred to as EPDM] each polyolefin 10
0 parts by weight, dipendylidene rubitol (hereinafter referred to as nucleating agent-1), di-pt-butyl monohydroxybenzoic acid (hereinafter referred to as nucleating agent-2), di-
p-methylbenzylidene sorbitol (hereinafter referred to as nucleating agent-3)
) and sodium benzoate (hereinafter referred to as nucleating agent-4) were blended in the proportions shown in Table 1 to form a composition, which was molded by injection molding into test piece 1. Obtained A coating film performance test was conducted by plasma treating the test piece.
The results are shown in Table-1.

For comparison, an experiment similar to Example 1 was carried out in the case where no nucleating agent was used and when calcium stearate and hindered aban [manufactured by Sankyo Co., Ltd., Sanol LS 770 (trade name)] were used instead of the nucleating agent. Complete all actions and display the results.
Also listed in 1.

Claims (1)

[Claims] Nucleating agent 0.0 per 100 parts by weight of polyolefin resin
1. A method for surface treatment of a polyolefin resin molded article, which comprises subjecting the surface of the molded article containing 1 to 2 parts by weight of the polyolefin resin to plasma treatment.