JPS6094336A - Surface treatment of synthetic resin molded piece - Google Patents

Abstract

PURPOSE:To improve coating property and adhesion property in a synthetic resin molded piece by conducting plasma treatment after conducting ultraviolet treatment to the surface of the synthetic resin molded piece. CONSTITUTION:Ultraviolet rays are irradiated to a synthetic resin molded piece. The wave length applicable is 250-700nm, preferably, 350-400nm. The irradiating time is desired to be established according to the wave length and strength of ultraviolet ray and the state of deterioration of the synthetic resin molded piece. Then, the plasma treatment is conducted. About 13.56MHz is especially preferable as the wave length. Oxygen is used for reactive gas supplied to the plasma treatment apparatus and nitrogen is used for purge gas. The normal pressure or the reduced pressure is sufficient as the pressure of the reactive gas, especially a zone between 0.1 and 1.7Torr is preferable.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for surface treatment of synthetic resin molded products, and provides a method suitable for pre-treatment processes such as painting and adhesion on the surface of synthetic resin molded products. be.

[Prior art]

The surface of a synthetic resin molded product is generally in an inert state, so it is unsuitable for painting or adhesion as it is.To overcome this drawback, surface treatments such as plasma treatment and ultraviolet treatment are performed.

It is true that this plasma treatment considerably improves paintability and adhesion. However, the effects of plasma treatment on improving paintability and adhesion are often insufficient in the following cases.

■Depending on each grade of each material, there are grades for which plasma treatment is insufficient for practical use. Furthermore, there are some grades in which sufficient effects cannot be obtained depending on the molding conditions.

For example, in molded articles made of polypropylene homopolymer or polypropylene copolymer, the paint peeling strength is significantly reduced.

■ In the case of large synthetic resin molded products, variations in plasma processing occur depending on the location within the plasma processing equipment.

As an example of this, when an automobile bumper is manufactured from a synthetic resin molded product and treated by storing it in a plasma processing apparatus, the treatment of (11!1) parts of the bumper is often insufficient.

In addition, the surface treatment method of synthetic resin molded products using ultraviolet rays requires a long time to be effective by itself, and in order to further increase the effect, a sensitizer must be applied in advance, and then of! A step of washing the sensitizer after IQ injection is necessary.

[Purpose of the invention]

The inventors of the present invention have conducted intensive studies on the plasma treatment and ultraviolet treatment described above for the purpose of improving the paintability and adhesion of synthetic resin molded products, and have confirmed that a certain combination of these treatments has a remarkable effect. Ta.

The present invention was obtained based on the above findings, and includes:
The present invention provides a surface treatment method for synthetic resin molded articles that has considerably increased effects compared to the effects obtained by plasma treatment or ultraviolet treatment alone.

The present invention for achieving the above object is characterized in that after the surface of a synthetic resin molded article is irradiated with ultraviolet rays, plasma treatment is subsequently performed.

An important point in the present invention is that it is necessary to perform two combined steps: irradiating the synthetic resin molded product with ultraviolet rays and plasma treatment, and the order may be changed. And 'J' fruit becomes insufficient.

[Plasma treatment] is, for example, BRANSON IPC
Company m3oos-no2o 5TQA etc. can be used.

Various frequencies are selected for the high frequency in the device depending on the characteristics of the resin, but according to the experimental results of the present invention, especially 1
A range of about 3.56 MIIZ was preferable.

In addition, the reactive gas supplied to the plasma processing equipment is oxygen,
It is preferable to use nitrogen gas as the purge gas.

The pressure of the reaction gas may be normal pressure or reduced pressure, and is preferably in the range of 0.1 to 1.7 Torr for ships.

The wavelength of [ultraviolet ray treatment] is 250 to 700 nm, preferably 350 to 400 nm.

As the light source for generating this ultraviolet ray, a carbon arc lamp, a xenon arc lamp, a UV curing lamp, or the like, which does not significantly progress the deterioration of the resin during this treatment, is used.

The irradiation time of ultraviolet rays is preferably set based on the ripples and intensity of the ultraviolet rays and the state of deterioration of the synthetic resin molded product.

[Effects of the Invention] Since the present invention is carried out as described above, as will be described in detail in the Examples, the adhesion of the paint and adhesive becomes stronger compared to the case of only plasma treatment or ultraviolet treatment.

Therefore, (1) Even if plasma treatment alone is insufficient for practical purposes, it is possible to put coating and adhesion into practical use.

(2) In the case of only plasma treatment, the selection range of resins to be used as materials for synthetic resin molded products was narrow, but according to the present invention, it is possible to widen the selection range of resins.

(3) With conventional surface treatment methods, the surface treatment effect varied depending on the molding conditions of the synthetic resin molded product, but with the present invention, there is no need to worry about variations in the molded product due to molding conditions. , suitable for mass production.

(4) If variations occur within the plasma processing equipment,
By irradiating the lower limit of the variation with ultraviolet rays in advance, it is possible to uniformly treat the surface.

In particular, various industrial effects can be achieved, such as increasing the size of the processing equipment and eliminating the need for a device for rotating synthetic resin molded products within the processing equipment.

〔Example〕

Next, the effects of the present invention will be explained using examples.

[Example-1] After treating the surface of a synthetic resin molded product under the following conditions,
A coating was applied to the surface, and the peeling strength of the coating film was measured.

(1) Using polypropylene BC-8D manufactured by Mitsubishi Yuka Co., Ltd., a synthetic resin board measuring 1 ltoo m long, 100 ++ m wide, and 2 mm thick was manufactured.

Paint R-263 manufactured by Nippon B Chemical Co., Ltd. was applied to the surface of the test piece.

(2) Plano and 1 Riso W: BRANSON IPC 3005-11
0203T[]A high frequency: 13.56 MIIZ Reaction chamber Nigarasu 240φX480 IIi+ (cylindrical type) Processing: Reaction gas = 02, purge gas 2N2O2 gas pressure 1.0 Torr O2 gas flow rate: about 30cc/min.

High frequency output crab 200W (3) Shugaiho treatment Ultraviolet lamp for curing UV curing adhesive Wavelength: 250
~700nm Electric crab 450W (Input density 300W/cm
)(4)? ΣShobee 1 ngue, 12 狽l paint includes main agent: R163 (manufactured by Nippon Bee Chemical Co., Ltd.), hardening agent: R-230, thinner: T-801゜weight ratio - main agent: hardening agent: thinner = 100: 25:3
0 The thickness of the coating film is approximately 50 μm, and the coating film is 10 mm wide and 1
The film was peeled off in an 80° direction, and the peel strength at that time was measured.

Under the above conditions, (1) UV irradiation time: 0.5 minutes, 1 minute, 10 minutes, 30 minutes
(2) A group in which plasma treatment was applied for an additional 30 seconds after this ultraviolet irradiation time; (3) A group in which plasma treatment was applied for 30 seconds and then the time of ultraviolet treatment was varied; 4) The results of measuring the beering strength of the coating films in the four groups that received only plasma treatment were as shown in Table 1.

As is clear from Table 1, the beering strength was 0.12 kBf/cm even after being treated with ultraviolet light for 30 minutes, which was about 10 minutes. It was found that the effect of surface treatment cannot be expected at all in this treatment.

Those in group (2) have a beering strength of 0.67.
~0.86, and it was found that the plasma treatment performed for 30 seconds after 10 minutes of ultraviolet treatment showed an excellent effect.

Group (3) ＼ Peeling strength is 0.60 ~
0.22, and it can be seen that the beering strength decreases as the ultraviolet treatment time increases.

The peeling strength of the group (4) was 0.64, which indicates that a remarkable surface treatment effect can be obtained only by this plasma treatment.

From the above examples, it can be seen that although plasma treatment is suitable for surface treatment of synthetic resin molded products, performing plasma treatment after ultraviolet treatment as in group (2) has a better surface treatment effect. .

[Example-2] The test piece used in Example-1 had a thickness of 2 dragons, but a 3 dragon plate-shaped test piece made of the same material was used to change the ultraviolet treatment time. was applied, and then plasma treatment was performed for 30 seconds to confirm the effect.

The ultraviolet irradiation time before plasma treatment is 5.10.1.
5.20.30.60.120 minutes and 20.40.10
The effect was confirmed by changing the time to 0 hours. The results are shown in Table 2.

As shown in Table 2, 11 ultraviolet treatment shows sufficient effects in 5 to 10 minutes, and when the treatment lasts for more than 15 minutes, the beering strength of the coating gradually decreases, and at 100 hours, it shows sufficient effect after 5 to 10 minutes. It can be seen that the peel strength is approximately 1/2 that of that treated with.

(Margin below) Table two soils Table 22 Otsu

Claims (1)

[Claims] A method for surface treatment of a synthetic resin molded article, which comprises performing a plasma treatment on the surface of the synthetic resin molded article after applying ultraviolet light treatment to the surface of the synthetic resin molded article in pretreatment such as painting.