JPH0246060B2 - PUROPIRENKEIJUSHISEIKEIBUTSUNOHYOMENSHORIHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of a propylene resin molded article, and more specifically, the present invention relates to a method for surface treatment of a propylene resin molded article, and more specifically, it improves the paintability, printability, and This invention relates to a method for improving adhesive properties, etc. Propylene resin has mechanical and thermal properties,
It is a relatively inexpensive resin with excellent moldability, so it is widely used in various fields, but it is also used in paints, inks,
Due to its poor adhesion to adhesives, its use in applications requiring painting, printing, and adhesion is limited, and improvements in its adhesion are being considered. An effective method for this purpose is to improve the adhesion of the molded product surface by low-temperature plasma surface treatment using oxidizing gas, but even this plasma treatment method cannot sufficiently achieve the adhesion required in actual applications. The current situation is that we are not satisfied. In view of the current situation, the present invention provides a method for surface treating a propylene-based resin molded article using low-temperature plasma, which can provide a high level of adhesive performance by using a specific propylene-based resin. The method for surface treatment of a propylene-based resin molded article of the present invention involves treating the surface of a molded article made of a propylene-based resin with low-temperature plasma. It is characterized by being a copolymer. (1) The xylene soluble content at room temperature is 3 to 40% by weight, and the ethylene content of the xylene soluble content is 10 to 40% by weight.
Must be 80% by weight. (2) The xylene insoluble content at room temperature is 97 to 60% by weight, the ethylene content of the xylene soluble content is 20% by weight or less, and the main melting peak temperature is 130 to 158°C. This ethylene propylene block copolymer is
For example, Special Publication No. 44-16668, Special Publication No. 47-26190
No., JP-A-47-25291, JP-A-50-115296,
It can be obtained by using the manufacturing method described in JP-A-54-24995 and other publications. These are usually substantially crystalline blocks consisting of a block portion consisting of an ethylene propylene block copolymer containing a small amount of ethylene and a block portion consisting of an ethylene propylene random copolymer containing a relatively high content of ethylene. It is a synthetic resin. Note that the former and latter blocks contain butene.
In some cases, α-olefin such as No. 1 is further copolymerized. These ethylene propylene block copolymers are usually referred to as a xylene-soluble component (hereinafter referred to as CXS) and an insoluble component as CXIS at room temperature. ). Generally, the former is an amorphous component and the latter is a crystalline component. The present invention has succeeded in imparting advanced adhesive performance in low-temperature plasma treatment by specifying the CXS and CXIS structures of the ethylene propylene block copolymer. That is, the ethylene propylene block copolymer used in the present invention contains (1) 3 to 40% by weight of CXS;
Preferably 4-30% by weight, particularly preferably 5-25%
% by weight, the ethylene content of the CXS is 10 to 80% by weight, preferably 20 to 70% by weight, particularly preferably 25
~65% by weight, and (2) CXIS is 97 to 60% by weight, preferably 96 to 70% by weight, and the ethylene content of the CXIS is 20% by weight or less, preferably 15% by weight.
Below, the main melting peak temperature is 130-158°C, preferably 132-157°C. If CVS is less than 3% by weight or more than 40% by weight, if CXS has an ethylene content of less than 10% by weight, and if CXIS has an ethylene content of 20% by weight
If the ethylene content of the CXS exceeds 80% by weight, the surface layer of the molded product tends to peel off in layers, making it difficult to use practical adhesion. Strength cannot be obtained. Furthermore, if the CXS is less than 3% by weight and the ethylene content of CXS is less than 10% by weight, the impact strength of the molded product will be low and it will be impractical. In addition,
When the main melting peak temperature of CXIS is outside the range of 130 to 158° C., it is generally difficult to obtain a high degree of adhesive performance because the structure of CXS and CXIS needs to be more strictly defined. The melt flow rate (MFR) of this ethylene propylene block copolymer is not particularly limited, but the value according to JIS K7210 is 0.1 to 100.
g/10 min is preferable, especially 1 to 80 g/10
Minutes are preferred. In order to improve adhesion by low-temperature plasma treatment, it is effective to add a small amount of organic peroxide and melt-knead it to increase the MFR, but the MFR in this case also falls within the above range. The ethylene propylene block copolymer may include low to high density polyethylene, ethylene vinyl acetate copolymer, as long as the characteristics of the present invention are not impaired.
Plastics such as ethylene-butene-1 copolymer, homopolypropylene, ethylene-propylene random copolymer, propylene-butene-1 random copolymer, ethylene-propylene copolymer rubber, ethylene-propylene diene copolymer rubber, styrene-butadiene block copolymer Elastomers such as combined rubber, talc, calcium carbonate, barium sulfate, titanium oxide, inorganic fillers such as glass fiber, colorants,
Antioxidants, neutralizing agents, ultraviolet absorbers, ultraviolet inhibitors, crystallization nucleating agents, etc. may be added as desired. The molded product may be molded by any method such as injection molding, extrusion molding, or blow molding, 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 gas, 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 to 10 torr and the processing time is 5 seconds to 15 minutes. It is also effective to clean the surface of the molded article with 1,1,1-trichloroethane vapor or the like before treatment. It is not clear why molded articles made of the ethylene propylene block copolymer specified in the present invention have a great effect of improving adhesion by low-temperature plasma treatment. However, when the cross section of the molded product is ion-etched and observed with a scanning electron microscope, it is found that domains mainly composed of CXS are dispersed in a matrix mainly composed of CXIS. The diameter of the copolymers of the present invention is often about 2μ or less, whereas the diameter of copolymers other than the present invention is often more than about 2μ, indicating that the fineness of the domain-dispersed particles is effective. In addition, it is presumed that because the matrix component contains chemically bonded ethylene, it also has a high affinity with the dispersed phase that also contains ethylene. In the present invention, CXS and CXIS of the ethylene propylene block copolymer, the ethylene content of both, and the main melting peak temperature of CXIS are as follows:
Each measurement was performed using the following measurement method. Approximately 0.7 g of CXS and CXIS samples were poured into approximately 300 c.c. of xylene, and
After dissolving by refluxing for a minute, leave to stand at room temperature, cool and filter, evaporate the liquid to dryness, and calculate CXS from the solid weight.
The cake was also dried and CXIS was determined from its weight. Ethylene content of CXS and CXIS The CXS and CXIS obtained in the above measurement were used as samples and measured by ¹³ C-NMR method. The measuring device is a JEOL FX-200NMR device, and the pulse interval
Measured under conditions of 30 sec, pulse width 45°, and complete decoupling. Main melting peak temperature of CXIS Using the CXIS obtained in the above measurement as a sample, using a PerkinElmer DSC (differential scanning calorimeter),
After heating and melting 5.0 mg of the sample at 250°C for 3 minutes under a nitrogen stream, it was cooled to 60°C at a cooling rate of 10°C/min to crystallize it, and then melted at a heating rate of 10°C/min while taking a thermogram. was obtained, from which the main melting peak temperature was read. In addition, temperature correction is "thermal measurement"
3, 83 (1976), etc. The effects of the present invention will be clarified by Examples and Comparative Examples below. Examples and Comparative Examples Various ethylene propylene block copolymers made of CXS and CXIS shown in Table 1 (MFR is
All about 5g/10 minutes. ), 0.2 parts by weight of 2,6-di-t-butyl-4-methylphenol (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) was added as an antioxidant, and 50O
It was pelletized using a single screw extruder (manufactured by Thermoplastics). Adhesion test pieces were made using an injection molding machine (N made by Japan Steel Works, Ltd.).
−100) obtained by 100mm×100mm×3mmt
This is the board. Low-temperature plasma surface treatment was performed using a microwave plasma treatment device (TMZ-9602B manufactured by Tokyo Shibaura Electric Co., Ltd.) using oxygen gas at a flow rate of 400 c.c./min and a pressure of 0.5 torr.
Processed for 10 seconds at an output of 400W. The adhesion test was conducted using the following method. After the plasma treatment, a two-component urethane paint (manufactured by Nippon B Chemical Co., Ltd., R-263) was spray-coated to a film thickness of approximately 100 to 120μ, and the test piece was heated at 90℃ for 40 minutes.
Bake for a minute. Next, a 10 mm wide cut was made in the coating film, and a strip of coating film was peeled off from one end, folded back in the opposite direction, and subjected to a 180° peel test (using Shimadzu Autograph P-100, pulling speed 20 mm/min).
Did. The results are shown in Table 1. [Table] [Table]

Claims (1)

[Scope of Claims] 1. In treating the surface of a molded article made of propylene resin with low-temperature plasma, the propylene resin is an ethylene-propylene block copolymer that satisfies the following (1) and (2). A method for surface treatment of propylene resin molded articles. (1) The xylene soluble content at room temperature is 3 to 40% by weight, and the ethylene content of the xylene soluble content is 10 to 40% by weight.
Must be 80% by weight. (2) The xylene insoluble content at room temperature is 97 to 60% by weight, the ethylene content of the xylene insoluble content is 20% by weight or less, and the main melting peak temperature is 130 to 158°C.