JPS6039290B2 - Method for imparting hydrophilicity to vinyl chloride resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for imparting hydrophilicity to vinyl chloride resin molded articles.

Molded products made from vinyl chloride resins have drawbacks such as non-hydrophilic surface characteristics, such as being easily charged with static electricity and poor printability.

As a way to solve this drawback, attempts have been made to treat the surface of the molded product with low-temperature plasma, which makes the surface of the molded product hydrophilic, imparts antistatic properties, and improves printability. This effect is expected. However, even if conditions such as low-temperature plasma processing gas pressure, gas flow rate, and applied power are kept constant, it is not possible to obtain the desired processing effect with good reproducibility. This was also observed when low-temperature plasma treatment was performed, and the treatment effect was unreliable.
As a result of intensive research into this technical problem, the present inventors have found that the effect of imparting hydrophilicity to vinyl chloride resin molded products through low-temperature plasma treatment depends on the surface temperature of the molded product to be treated and the input side for low-temperature plasma generation. The present invention was achieved by discovering that this is subtly influenced by the relationship with the electrode temperature. That is, in the present invention, a vinyl chloride resin molded product is placed in an internal electrode discharge type low-temperature plasma generator, and - the temperature of the molded product (T
, °C) and input side electrode temperature (too), respectively.
, = 0 to 80 20 - A method for imparting hydrophilicity to a vinyl chloride resin molded article, characterized by treating it with low-temperature plasma of an inorganic gas of 10 Torr or less while maintaining TI≦T2 100 According to this method, the surface of the molded article can be reliably modified, the effect of improving hydrophilicity is extremely remarkable, and the advantage is that this can be achieved with good reproducibility.

The method of the present invention will be explained in detail below.

First, the vinyl chloride resin molded product to which the method of the present invention is carried out may be either a soft molded product or a hard molded product, and it may be made of polyvinyl chloride or a copolymer mainly composed of vinyl chloride as a resin raw material. Any molded product molded using a molded product such as a film or sheet, a tubular body such as a tube or a hose, or other irregularly shaped products are eligible, and there are no restrictions on the shape or type of the molded product.

As mentioned above, copolymers mainly composed of vinyl chloride include vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-acrylonitrile copolymer, and vinyl styrene chloride copolymer. Polymer, vinyl chloride styrene-butadiene copolymer,
Examples include vinyl chloride-vinylidene chloride copolymers and graft copolymers mainly composed of polyvinyl chloride.

These vinyl chloride resins are not limited to one type, but may be used as a blend of two or more types, and other synthetic resins may be blended for the purpose of improving the mechanical strength of the molded product. The resins include ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, styrene-acrylonitrile copolymer, methyl methacrylate-styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, and ethylene-propylene. Elastomer, ethylene carbon. Examples include pyrene-gene elastomer, polyamide resin, caprolactam polymer, epoxy-modified polybutadiene, epoxy-modified polyol, and organopolysiloxane. Various additives are added to the vinyl chloride resin composition as necessary, and these additives include plasticizers, stabilizers, lubricants, fillers, pigments, dyes, ultraviolet absorbers, antioxidants, and crosslinking agents. , a vulcanization accelerator, and various surfactants (cationic, anionic, nonionic, amphoteric) are used as appropriate.

The vinyl chloride resin molded article may be obtained by any molding method employed in conventional vinyl chloride resin molding, such as extrusion molding, injection molding, calendar molding, inflation molding, or compression molding.

The molded product thus obtained is then subjected to low-temperature plasma treatment, and in the method of the present invention, an internal electrode discharge type low-temperature plasma generator is used as the plasma generator, and the plasma treatment conditions are adjusted to the temperature of the molded product to be treated. T.
0 and the input side electrode temperature is L°C, then T,=0
~80 20 - It is necessary to satisfy TI≦T2≦100.

If this condition is not satisfied, it becomes difficult to stably achieve the effect of imparting hydrophilicity with good reproducibility. An internal electrode discharge type low-temperature plasma generator is a type in which an electrode is placed inside the generator in contact with an inorganic gas.The low-pressure inorganic gas introduced inside is turned into plasma near the electrode, and this is generated by the generator. It acts on the surface of the molded article placed inside, achieving the desired modification, that is, imparting hydrophilicity to the surface of the molded article.

Various shapes such as a flat plate type, a net type, a coil type, and a square type are selectively used as the input side power, but in the present invention, a temperature control means is provided to satisfy the above-mentioned temperature conditions. For this purpose, it is desirable to use an electrode that allows a heating medium to flow inside the electrode.

To control the temperature of the molded product to be processed, for example, a metal plate-like electrode that can control the temperature is used as the ground side electrode, and the molded product to be processed is layered on this electrode, and the molded product placed on it is controlled by controlling the temperature of the electrode. A method such as controlling the temperature of the product may be used.

Further, when a tube-shaped molded body is subjected to continuous low-temperature plasma treatment, it is convenient to flow a heat medium at a predetermined temperature into the tube. To generate low-temperature plasma, an inorganic gas is introduced into the device, and the electrodes are heated, for example, at 13.5 Isogo, 10~
It is sufficient to apply a power of 70 cm.

The low-temperature plasma treatment time for a molded article varies depending on the applied voltage, but generally a few seconds to several tens of minutes is sufficient. As the discharge frequency band for generating low-temperature plasma, in addition to the above-mentioned high frequency, low frequency, microwave, direct current, etc. can be used. Helium is an inorganic gas,
Examples include neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, chlorine, as well as hydrogen chloride, sulfur dioxide gas, and hydrogen sulfide.
These gases may be used alone or in combination.

The gas pressure of these gases in the plasma generator is required to be such that the desired low-temperature plasma can be easily generated, that is, 10 Torr or less (preferably 0.01 Torr to 1 Torr). By subjecting the molded article to low-temperature plasma treatment in this manner, the desired surface modification of the molded article can be achieved in an extremely short period of time. Next, examples of the present invention will be given.

Example 1 10 parts by weight of vinyl chloride resin (TK-1000, trade name manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by weight of calcium-zinc stabilizer,
170 qo of a formulation consisting of 3 parts by weight of epoxy stabilizer
This was rolled for 10 minutes and then press-molded at 180 qo to create a sheet with a thickness of 0.5 willow.

One piece of this sheet (sample sheet) was placed on the flat metal ground electrode in the internal electrode discharge type low temperature plasma generator, and CO- to -N2 (capacity ratio 8:1:1) was mixed inside the device. The pressure is adjusted and maintained at 0.5 torr while gas is vented, and the temperature is controlled by circulating a heating medium inside both the input side electrode and the ground side electrode in the device, and the sample sheet is placed on the ground side. It was kept at the same temperature as the electrodes. Low-temperature plasma was generated by applying a high frequency of 13.58 MHz and 500 W to the input side electrode, and the sample sheet was subjected to low-temperature plasma treatment for 3 minutes.

When the hydrophilicity of each treated sheet was examined by controlling the temperature of the input side electrode and sample sheet to various values in the above, the results shown in Table 1 were obtained.

Hydrophilicity: Contact angle with water at temperature 25q0 Table 1 (contact angle with water, degree, 25°C) Example 2
5 parts by weight of vinyl chloride resin (TK-1300, trade name manufactured by Shin-Etsu Chemical Co., Ltd.), vinyl chloride-vinyl acetate copolymer resin (
SC-40 product name manufactured by Shin-Etsu Chemical Co., Ltd., vinyl acetate content (IZ weight %) 5 parts by weight, tin calcium stabilizer 1
．． A blend consisting of part by weight of the box and 1 part by weight of the epoxy stabilizer was kneaded at 160o0 between rolls of flour,
A sheet having a thickness of 0.5 mm was prepared by press molding with 000.

One piece of this sheet (sample sheet) was placed on the flat metal ground electrode in an internal electrode discharge type low-temperature plasma generator, and the pressure was adjusted and maintained at 0.1 Torr while argon gas was vented into the device. The temperature of both the input electrode and the ground electrode in the apparatus was controlled by circulating a heating medium inside them, so that the sample sheet was kept at the same temperature as the ground electrode.

Low-temperature plasma was generated by applying a high frequency of 13.58 MHz and 500 W to the input side electrode, and the sample sheet was subjected to low-temperature plasma treatment for 2 minutes.

When the antistatic property of each of the treated sheets was examined by controlling the temperature of the input side electrode and the sample sheet at various values in the above, the results shown in Table 2 were obtained.

Antistatic property test method: Measured using a rotary static tester manufactured by Koa Shokai, Conditions: Cotton cloth, 200g load, 75ppm, 3mm, RH50% (2yo) Table 2 [Frictional charging voltage M] Example 3 Example 20 sample sheets prepared using the same machine as No. 1 were prepared.

For each of the 10 sheets, type and pressure of gas: argon gas, 〇. 3 Torr Input side electrode temperature: 40q0 Controlled sample temperature: 40°C High frequency: 13.5 Mother M ratio, 700W Low temperature plasma treatment was performed according to Example 1 under the conditions of 1 minute treatment time, and the contact angle (degrees) with respect to water was , 25qo) and frictional charging voltage (V) were measured.

Each of the other sample sheets lq was subjected to low-temperature plasma treatment in the same manner as above, except that the temperature of the input electrode and sample was not controlled at all, and the contact angle with water (degrees, 25 mm) and friction The charging voltage (V) was measured.

The respective measurement results are shown in Table 3. By controlling the temperature of the input side electrode and sample sheet, sufficient processing effects can be achieved with good reproducibility, but if temperature control is not performed, It can be seen that the processing effect varies greatly and the reproducibility is extremely poor.

Table 3 ×1. : When temperature is controlled *2. : When temperature is not controlled

Claims (1)

[Claims] 1. A vinyl chloride resin molded product is placed in an internal electrode discharge type low temperature plasma generator, and the temperature of the molded product (T_1°C) and the input side electrode temperature (T_2°C) are set as T_1=
A method for imparting hydrophilicity to a vinyl chloride resin molded article, the method comprising treating it with low-temperature plasma of an inorganic gas of 10 torr or less while maintaining 0 to 80 20-1/5T_1≦T_2≦100.