JPH0216337B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a method for surface treatment of a propylene-based resin composite material formed by blending and kneading talc and ethylene-propylene rubber with a propylene-based resin, and in particular, the particle size and blending ratio of the talc, and the blending ratio of ethylene-propylene rubber. The present invention relates to a method for surface treatment of a propylene-based resin composite material molded article. As a conventional surface treatment method of this type, there is the following method already proposed by the applicant of the present application. This method is disclosed in Japanese Patent Application No. 54-159733. This is a molded product made by molding a propylene resin composite material, which is made by mixing and kneading 5 to 60% by weight of inorganic fine powder such as talc, heavy charcoal, colloidal charcoal, and precipitated barium sulfate with propylene resin. This is a method in which the surface is treated with oxidizing low-temperature plasma. According to this method, for example, the adhesive strength when bonding another molded body to the molded body using an adhesive or the like, or the adhesion when a paint or the like is applied to the molded body can be significantly improved. The reason is that when treated with oxidizing plasma, in addition to the polarization effect on the surface of the compact, it is assumed that surface activation due to exposure of inorganic fine powder with a polar surface and anchoring effect due to the formation of surface irregularities contribute. Ru. However, the adhesive strength is still insufficient under harsh usage conditions, and this can be improved by appropriately selecting the conditions for surface treatment with oxidizing plasma.
In general, it is possible to improve the adhesive strength to some extent, but for composite materials containing talc, the effect is not fully demonstrated even if the plasma treatment conditions are selected, and there is a limit to the improvement of adhesive strength. Ta. That is, since the shape of the talc particles is generally flat, the talc particles are likely to be arranged in parallel to the surface of the molded product in an overlapping manner near the surface of the molded product. Therefore, if the surface of a molded body in which such talc particles are arranged parallel to each other near the surface is treated with oxidizing low-temperature plasma, the surface adhesion itself will be improved, but the adhesive bonded to the molded body will be Depending on the severe usage conditions and mode of use, the talc on the surface layer of the molded product may peel off, resulting in the problem that the paint applied to other molded products may be easily removed or peeled off. In particular, the particle size of the talc particles is large,
When the particle size exceeds 10μ and the blending ratio increases, this phenomenon becomes noticeable. An object of the present invention is to provide a method for surface treatment of a propylene-based resin composite material molded article, which can solve the above-mentioned problems and significantly increase adhesive strength. That is, the method for surface treatment of a propylene-based resin composite material molded article according to the present invention comprises: a propylene-based resin; talc having an average particle size of 5μ or less and a particle size distribution of 4% by weight or less of particles of 10μ or more;
A propylene-based resin composite material made by blending and kneading 80 to 25% by weight, 5 to 30% by weight, and 15 to 45% by weight of ethylene propylene rubber, respectively, is molded, and the surface of the resulting molded product is treated with oxidizing low-temperature plasma. The content and feature is that it is processed by Here, the above-mentioned propylene resin refers to a propylene homopolymer, a block or random copolymer formed by copolymerizing propylene with 25% by weight or less of ethylene or other α-olefin, and the like. The average particle size of the talc may be 5 μm or less, but preferably 3 μm or less. Furthermore, it is necessary that the content of particles larger than 10μ is 5% by weight or less.
The particle size distribution is measured by a liquid phase sedimentation type light transmission method, for example, model CP-50 manufactured by Shimadzu Corporation, and the average particle size is the value at the cumulative value of 50%. Note that the specific surface area is preferably 30,000 cm ² /g or more. The specific surface area is measured using a constant pressure aeration type specific surface measuring device, for example, a powder specific surface area measuring device SS-100 manufactured by Shimadzu Corporation. The reason why the average particle size was set to 5μ or less and the particle size distribution of particles larger than 10μ was set to 5% by weight or less was that each 5μ
If the amount exceeds 5% by weight, the surface layer of the molded product is likely to peel off, and the effect of the oxidizing low-temperature plasma treatment will not be sufficiently exhibited. The above ethylene propylene rubber has a propylene content of 20 to 60% by weight and a Mooney particle size of ML1+4 (100
℃) 20~105 ethylene propylene rubber or ethylene propylene diene rubber. The reason why the amount of ethylene propylene rubber is limited to 15 to 45% by weight is that if it is less than 15%, it will not be effective in improving the adhesive strength when coating the molded product or bonding other molded products. This is because the effect of suppressing the drop in impact strength of the molded product due to talc filling becomes smaller.If it exceeds 45%, the surface layer of the molded product is likely to peel off, and the effect of improving the adhesive strength is reduced. At the same time, the rigidity of the molded product is significantly reduced, making it impractical. There are 5 reasons why the amount of talc is 5 to 30% by weight.
If it is less than 30%, the effect of improving the adhesive strength is small.
%, even talc having the above particle size and particle size distribution tends to cause surface layer peeling of the molded product. The propylene-based resin composite material may include synthetic resins such as low and medium density polyethylene, high density polyethylene, ABS resin, and nylon resin, rubbers such as styrene-butadiene rubber, and carbonic acid, within a range that does not impair the characteristics of the present invention. Calcium, barium sulfate,
There is no problem in containing one or more fillers such as titanium oxide, mica, and glass fiber, antioxidants, ultraviolet inhibitors, and colorants. The above-mentioned propylene resin, talc, and ethylene propylene rubber are blended and kneaded using a conventional kneading machine such as a single screw extruder, twin screw extruder, roll, or Banbury mixer. The molded article may be formed by any method such as injection molding, extrusion molding, or blow molding. In the treatment with oxidizing low-temperature plasma, a low-pressure oxidizing gas such as oxygen or a gas mixed with nitrogen, argon, etc. is excited by high-frequency discharge, microwave discharge, etc. to generate an active gas, and this is used to form a molded product. This is done by contacting the surface of the The treatment conditions are not particularly limited, but the pressure is usually 0.1 to 10 Torr, preferably 0.1 to 1.0 Torr, and the treatment time is usually 5 to 300 seconds. Examples of the present invention and comparative examples thereof are shown below, and the treatment method of the present invention imparts sufficient adhesive strength to the propylene-based resin composite material molded article to withstand severe usage conditions and modes. reveal what is possible. [] Example 1 and Comparative Example 1 This Example 1 and Comparative Example 1 clarify the particle size effect of talc. In Example 1, 65% by weight of propylene resin, 10% by weight of talc with an average particle size of 1.5 to 4μ, and 2 to 4% by weight of coarse particles of 10μ or more, and 25% by weight of ethylene propylene rubber were blended, respectively. A molded body obtained by molding the kneaded propylene-based resin composite material was treated with oxidizing low-temperature plasma, and then the molded bodies obtained were adhered to each other with an epoxy adhesive, and the epoxy adhesive strength was examined. The experimental conditions are as follows. (1) Compounding and kneading method of propylene-based resin composite material An ethylene-propylene block copolymer resin with an ethylene content of 18% by weight and a melt index of 25g/10 minutes is used as the propylene-based resin; mooney viscosity
Ethylene propylene rubber of ML1+4 (100°C) 70 and the talc shown in Table 1 were uniformly mixed in a high speed mixer, melt-kneaded and granulated in a twin screw extruder with L/0=25. (2) Molding method of molded body: Thickness 3 with injection molding machine (Japan Steel Works N-100)
A plate with a length of 100 mm and a width of 100 mm was formed. (3) Oxidizing low temperature plasma treatment method Internal electrode type high frequency plasma treatment machine (13.56M
Hz), with a discharge output of 200 W and 30 Hz while oxygen was flowing at 460 c.c./min at 0.5 Torr as the processing gas.
Plasma discharge treatment was performed for seconds. (4) Adhesive strength test method 15mm from the above board after oxidizing low temperature plasma treatment
Cut out two test pieces with a width of 50 mm and a length of 50 mm. Apply two-component curing epoxy resin adhesive (Konishi Bond Quick Set) to one surface of one of them, and cut the other one to a length of 7 mm. superimposed on,
Bonding was performed by applying a pressure of 1.2 kg/cm ² . Then 80℃
Heat it in an oven for 30 minutes to harden it. Tensile testing machine (Shimadzu Autograph IS-500)
A shear peeling test was performed at a speed of 20 mm/min using a machine to determine the maximum stress. The value obtained by converting this determined maximum stress into 1 cm ² is the epoxy adhesive strength. The results are shown in Table 1.

[Table] As is clear from Table 1, in Example 1 containing talc with an average particle size of 5μ or less and a particle size distribution of 5% by weight or less of coarse particles of 10μ or more, the epoxy adhesive strength was In contrast, in Comparative Example ¹ in which the particle size distribution of talc exceeds the above range, the epoxy adhesive strength is 30 Kg/cm ² or less. In addition, in the case of Comparative Example 1-, peeling of the adhesive surface layer of the plate was particularly noticeable. [] Example 2 and Comparative Example 2 In Example 2, the effect of the amount of talc in Example 1 was investigated. The propylene resin used was an ethylene propylene block copolymer with an ethylene content of 9% by weight and a melt index of 9 g/10 min, and the ethylene propylene rubber used was a rubber with a propylene content of 49% by weight and a Mooney viscosity of ML1+4 (100°C) 40. This and talc were kneaded in a Banbury mixer and then pelletized. The amount of ethylene propylene rubber blended was fixed at 25% by weight, and the amount of propylene resin blended was varied in accordance with the change in the amount of talc blended. Molding method of compact, oxidizing low temperature plasma treatment method,
And the adhesive strength test method is the same as in Example 1. The compounding amount and epoxy adhesive strength are shown in Table 2.

[Table] Looking at the results in this table, the appropriate blending amount of talc is 5
-30% by weight, and it can be seen that the effect of improving adhesive strength is low outside this range. [] Example 3 and Comparative Example 3 In Example 3, the effect of the blending amount of ethylene propylene rubber on paint adhesion was investigated.
The ethylene propylene rubber was used in Example 1, and the propylene resin was used in Example 2. The talc used had a particle size distribution in which the average particle size was 2.5μ and the proportion of particles larger than 10μ was 2% by weight. The amount of talc added is fixed at 12% by weight,
The amount of propylene resin blended was changed in accordance with the change in the amount of ethylene propylene rubber blended. The blending, kneading method, molding method and oxidizing low temperature plasma treatment method are the same as in Example 1. In order to examine the adhesion of the paint, that is, the adhesive strength, urethane paint (Kashiyu Co., Ltd., PB-2 acrylic urethane paint) was spray-painted (thickness 25μ) and heated at 60℃.
After heating and curing for 30 minutes, this coating film is tested for peeling off the base (make 100 2 mm square incisions with a razor, apply Nichiban cello tape, quickly peel it off, and measure the number of scratches on the coating that will not peel off). )Did. The results are shown in Table 3.

[Table] From this result, ethylene propylene rubber is 15 to 45
It can be seen that it is essential to mix % by weight.

Claims (1)

[Claims] 1 80 to 25% by weight of propylene resin, 5 to 30% by weight of talc with an average particle size of 5μ or less and a particle size distribution of 5% by weight or less of particles 10μ or more, and 15 to 45% by weight of ethylene propylene rubber. , the respective combinations,
1. A method for surface treatment of a propylene resin composite molded article, which comprises molding a kneaded propylene resin composite material and treating the surface of the obtained molded article with oxidizing low-temperature plasma.