JPS59109530A - Surface treatment of propylene resin molding - Google Patents

Abstract

PURPOSE:To improve the surface adhesiveness of a propylene resin molding, by plasma-treating the surface of the molding of a propylene resin comprising an ethylene/propylene copolymer resin having specified properties and an ethylene/ propylene copolymer rubber at a low temperature. CONSTITUTION:The following components A and B are mixed together so that the product of the limiting viscosity of component A and the Mooney viscosity of component B is 58 or greater: (A) 60-90wt% ethylene/propylene block copolymer resin having a xylene-soluble portion at ordinary temperature of 3- 30wt%, a xylene-insoluble portion at ordinary temperature of 97-70wt%, an ethylene content of the xylene-soluble portion of 25-80wt%, an ethylene content of the xylene-insoluble portion of below 10wt%, and a limiting viscosity in a decalin solution at 135 deg.C of 0.8-5dl/g, and (B) 40-10wt% ethylene/propylene copolymer rubber having a Mooney viscosity at 100 deg.C of 18-90. The produced resin is molded, and the surface of the molding is plasma-treated at a low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of a propylene resin molded product, and more specifically, the present invention relates to a method for surface treatment of a propylene resin molded product, and more specifically, by treating the surface of a propylene resin molded product with low-temperature plasma, surface adhesion such as paintability of the molded product is improved. Concerning how to improve sex.

Propylene resins are widely used in various fields because they are relatively inexpensive resins with excellent mechanical properties, thermal properties, and moldability. Among them, ethylene propylene block copolymer resins and ethylene propylene Propylene-based resins composed of compositions with polymer rubber have attracted attention in various fields including automobile bumpers because of their excellent impact resistance, but their adhesion to paints, adhesives, etc. is not necessarily good. For example, when applying a urethane paint with excellent toughness, gloss, oil resistance, abrasion resistance, etc. to a propylene resin molded product made from this composition, the surface of the molded product is etched with a solvent in advance, and then chlorine is applied to the surface of the molded product. It requires a complicated process of applying an undercoat mainly composed of a solvent-soluble resin with high affinity for propylene-based resins such as chlorinated polypropylene or chlorinated rubber, and then applying the urethane paint on top of that. Adhesion between the material propylene resin and the coating film is not necessarily sufficient. Furthermore, even if this propylene-based resin is subjected to low-temperature plasma treatment using oxidizing gas, which is known as a method for improving the surface adhesion of various resins such as polyolefin,
At present, it is not possible to sufficiently stably satisfy the adhesive force required for actual use.

In view of the current situation, the present inventors have conducted repeated studies on improving the adhesion of a propylene-based resin made of a composition of an ethylene-propylene block copolymer resin and an ethylene-propylene copolymer rubber by low-temperature plasma treatment. The adhesion improvement effect of paints, adhesives, etc. depends on the dispersion shape of the ethylene propylene copolymer rubber in the propylene resin, and by appropriately controlling this dispersion shape, the adhesion improvement effect can be stabilized. They discovered that in order to obtain the desired results and the dispersed shape of the resin, the ethylene propylene block copolymer resin and the ethylene propylene copolymer rubber that constitute the resin must each be specific. Completed the invention.

Therefore, the present invention provides a method for surface treating a propylene resin molded article using low-temperature plasma, which can provide a high level of adhesive performance by using a specific propylene resin.

That is, the method for surface treatment of a propylene resin molded article of the present invention consists of the following (4) and (b), and the surface treatment method of a propylene resin molded article made of a composition that satisfies the following (Q). It is characterized by being treated with low-temperature plasma.

(4) (a) Xylene soluble content at room temperature is 3 to 30% by weight
and the ethylene content of the xylene soluble portion is 25 to 8.
At 0% by weight, the intrinsic viscosity of decalin solution at 135°C is 0.
．． 8-s, octp/y, and (b) an ethylene-propylene block copolymer resin having a xylene-insoluble content of 97-70% by weight at room temperature and an ethylene content of the xylene-insoluble content of 10% by weight or less. ...60 to 90% by weight (B) Ethylene propylene copolymer rubber having a Mooney viscosity of 18 to 90 at 100°C ...40 to io weight% (O The above intrinsic viscosity and the above Mooney viscosity The product of this must be 58 or more.

The ethylene-propylene block co-polymer resin used here is obtained, for example, by using the production method described in JP-A-49-61278, etc., and is usually a propylene homopolymer or a small amount of ethylene-containing ethylene. It is a substantially crystalline resin composed of a block part made of a propylene random copolymer and a block part made of an ethylene propylene random copolymer containing a relatively high content of ethylene. Note that an α-olefin such as butene-1 may be further copolymerized in the former and latter blocks. This ethylene propylene block copolymer resin usually consists of a component that is soluble in xylene at room temperature (hereinafter referred to as CXS) and an insoluble component (hereinafter referred to as CXS).
It is classified by CXl5 (0). Generally, the former is an amorphous component and the latter is a crystalline component.

The ethylene propylene block copolymer resin in the present invention contains (a) 3 to 30% by weight of CXS, preferably 5 to 25% by weight, particularly preferably 6 to 15% by weight,
The ethylene content of XS is 25 to 80% by weight, preferably 30 to 70% by weight, particularly preferably 35 to 65% by weight, and the intrinsic viscosity [η]de'1' in a decalin solution at 135°C is 0.8. ~5.0dll?, 135°C, preferably 1.0~4.5dll?, and (b
) CXl5 is 97-70% by weight, preferably 95-7
5% by weight, particularly preferably 94-80% by weight of the CXl
The 5O ethylene content is 10% by weight or less, preferably 8% by weight or less, particularly preferably 0.5 to 6% by weight.

When CXS exceeds 30% heavy load, when the ethylene content of CXS exceeds 80% by weight, [η)7' of CXS
Force 'J'-' is 5.0 a/? If the CXI SO ethylene content exceeds 10% by weight, the effect of improving the adhesion of the plasma-treated molded product is insufficient, and if the CXS content is less than 3% by weight, the ethylene content of CXS Decanoa containing less than 25% by weight is o, s d
When i/ is less than [η]□350, the surface layer of the molded product tends to peel off in layers, and practical adhesive strength cannot be obtained.

The melt flow rate (MFR) of this ethylene propylene block copolymer resin is not particularly limited, but the value according to JIS K7210 is 0.1 to 100.
f/10 minutes is preferable, especially 1 to 801F/1
0 minutes is preferred.

The ethylene propylene copolymer rubber in the present invention is an ethylene propylene binary copolymer or an ethylene propylene diene terpolymer, and contains 20 to 5 % of propylene.
0% by weight, preferably 22 to 40% by weight, and 100% by weight.
Mooney viscosity MLi+4 at °C (1o o °C) is 18
-90, preferably 20-80.

When the propylene content is less than 20% by weight, the effect of improving the impact strength of the molded product is small, and when it exceeds 50% by weight, the elastic modulus and surface hardness of the molded product decrease, making it impractical. Furthermore, if the Mooney viscosity is less than 18, the surface layer of the molded product will tend to peel off in layers, making it impossible to obtain a practical adhesive strength, and if it exceeds 90, the effect of improving adhesion will not be sufficient.

The composition in the present invention is composed of the ethylene propylene block copolymer resin and the ethylene propylene copolymer rubber, and further contains the above [η] of CXS of the resin.
It is necessary that the product of the ML1+4 (135°C expressed in dll?) of the rubber is 58 or more, preferably 6
0 or more and 400 or less, particularly preferably 65 or more and 360
It is as follows. If this product is less than 58, sufficient adhesive strength cannot be obtained even if both components satisfy the above ranges.

The composition ratio of the ethylene propylene block copolymer resin and the ethylene propylene copolymer rubber is such that the former resin accounts for 60 to 90% by weight, preferably 65 to 85% by weight. If it is less than 60% by weight, surface peeling tends to occur, sufficient adhesive strength cannot be obtained, and rigidity is low. Also, 90% by weight
If it exceeds this, the impact strength will not be sufficient.

The composition of the present invention comprises the ethylene propylene block copolymer resin, the ethylene propylene copolymer rubber, and, if necessary, low to high density polyethylene, ethylene Resins such as vinyl acetate copolymers, rubbers such as styrene-butadiene block copolymer rubbers, inorganic fillers such as mata, talc, calcium carbonate, barium sulfate, titanium oxide, glass fibers, colorants, antioxidants, etc. Mixing agents, ultraviolet absorbers, ultraviolet inhibitors, crystallization nucleating agents, etc. are added as desired, and the mixture is melt-kneaded using a -screw extruder, twin-screw extruder, Banbury type mixer, etc., usually at a temperature of 200 to 250°C. It can be obtained by

The molded product may be molded by any method such as injection molding, extrusion molding, blow molding, etc., and is not limited to a specific product.

Low-temperature plasma treatment involves exciting a low-pressure oxidizing gas, such as oxygen, or a gas mixed with nitrogen, air, argon, carbon dioxide, chlorine gas, etc., using high-frequency discharge, microwave discharge, etc. to generate an active gas. This is done by bringing it into contact with the surface of the molded article. Processing conditions are not particularly limited, but usually the pressure is 0.1-10 torr and the processing time is 5 seconds to 15 minutes. Also, before processing, 1.1.1-
) The surface of the molded product may be cleaned with dichloroethane vapor, etc. In the present invention, the ethylene content of both CXS and CXl5 of the ethylene propylene block copolymer resin is determined by the following measurement method. It is.

About 0.71 of the CXS and CXI S samples were placed in about 300 cr of xylene;
After dissolution by refluxing for 15 minutes, the mixture was allowed to stand at room temperature, cooled, and filtered. Solution F was evaporated to dryness, and CXS was determined from the solid weight. The cake was dried and CXIS was determined from the weight.

Ethylene content of CXS and CXl5 Using the CXs and CXl5 obtained in the above measurements as samples, 13C-NMR
It was measured by the method. The measuring device is JEOL MFX-20ON.
The measurement was carried out using an MR device under complete Decara ring conditions with a pulse interval of 30 sec and a pulse width of 45°.

The effects of the present invention will be clarified by Examples and Comparative Examples below.

Various ethylene propylene block copolymer resins (manufactured by Mitsubishi Yuka Co., Ltd., MF
R is 4 to 10 f/10 minutes) and ethylene propylene copolymer rubber (manufactured by Japan Synthetic Rubber Co., Ltd.), and 2,6-di-t-butyl was added as an antioxidant to too M parts of the mixture. -4-Methylphenol (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) was added to 05 parts by weight of tetrakis-[methylene-a-1 (3,
5-di-t-butyl-4-hydroxyphenyl)glochionate] 0.05 parts by weight of methane (manufactured by Ciba Geigy) and 0.05 parts by weight of calcium stearate as a neutralizing agent.
05 parts by weight was added and pelletized using a 50e-shaft extruder (manufactured by Thermo Glassnack).

Adhesive test pieces were made using an injection molding machine (N-100 manufactured by Japan Steel Works).
) is a board of 100 mm x 100 mm x 3 mm.

The low-temperature plasma surface treatment was performed for 10 seconds at a flow rate of 4 ooec/min, a pressure of 0.5 torr, and an output of 400 W using oxygen gas using a microphone P-wave plasma processing apparatus (TMZ-9602B manufactured by Tokyo Shibaura Electric Co., Ltd.).

The adhesion test was carried out in the following manner.

A two-component urethane paint (manufactured by Nippon B Chemical Co., Ltd., R-z63) was applied to the test piece after plasma treatment to a film thickness of approximately 100 to 1.
It was sprayed to a thickness of 20μ and baked at 90°C for 40 minutes. Next, a 10-tone width cut was made in the coating film, and a strip of coating film was peeled off from one end and folded back in the opposite direction.
180° Beer test (Autograph p- manufactured by Takasugi Seisakusho)
100 was used, and the tensile speed was 20 tm for 7 minutes).

The results are shown in Tables 1 to 3. Table 1 shows the effects of the ethylene propylene block copolymer resin and ethylene propylene copolymer rubber components, and Table 2 shows the effects of the composition ratio of both components. Table 3 mainly shows the effects related to the product of intrinsic viscosity and Mooney viscosity.

(Margin below)

Claims (1)

[Scope of Claims] Propylene characterized in that the surface of a molded product of a propylene resin made of a composition that is more similar to the following material and (B) and that satisfies the following 0 is treated with low-temperature plasma. A method for surface treatment of molded resin products. (A) (a) The xylene soluble content at room temperature is 3 to 30% by weight, and the ethylene content of the xylene soluble content is 25% by weight.
-80% by weight, the intrinsic viscosity of the decalin solution at 135°C is 8-5.0 dll's, and (b) the xylene-insoluble content at room temperature is 97-70% by weight, and the xylene-insoluble content contains ethylene. Ethylene propylene block copolymer resin with a ratio of 10% by weight or less...60 to 90% by weight (B) Ethylene propylene copolymer rubber with a Mooney viscosity of 18 to 90 at 100°C... ...40 to 10% by weight 0 The product of the limiting viscosity and the Mooney viscosity is 58 or more.