JPH038661B2 - - Google Patents

Description

[Detailed description of the invention]

Technical Field The present invention relates to a method for surface modification of polyvinyl chloride resin molded articles. More specifically, the present invention relates to a method for eliminating surface cracks without impairing the properties of polyvinyl chloride resin or the shape of molded products thereof. BACKGROUND ART Polyvinyl chloride resins have good processability, high strength, and are inexpensive, so they are used in a wide range of applications. However, as the polyvinyl chloride resin melts and gels when heated, a gloss unique to polyvinyl chloride, so-called "shininess" occurs on its surface. Therefore, in applications such as high-end interiors,
The reality is that its use is restricted. Methods to solve these problems include sandblasting, etching with a chromium mixture,
Known methods include a squeezing method using an engraved erasing roll, a surface treatment method using a resin containing an erasing agent such as silica, and a method of kneading and melting a high polymerization degree resin and a low polymerization degree resin. However, each of these methods has major problems. For example, in the sandblasting method, not only does it require a long treatment time to obtain the removal effect, but also a large amount of sand adheres to and remains on the surface, which is difficult to remove. In addition, the etching method using a chromium mixture has problems in the disposal of waste liquid and has the drawback of inducing bleeding of plasticizers and other fillers contained in molded products. Furthermore, in the engraving roll method for erasing,
The patterns available are limited, and the workmanship requires high costs. Furthermore, in methods using surface treatment agents, if the treatment agent is water-based, the resulting faded surface will have poor durability, and if the treatment agent is used together with an organic solvent, the smell of the solvent will remain in the product for a long time. It has drawbacks. Furthermore, the method of kneading and melting low polymerization degree resin and high polymerization degree resin has the problem that if the heating temperature applied to the product is high, the erasing effect will be lost, while if the heating temperature is low, the properties of the resin itself will be impaired. are doing. Problems to be Solved by the Invention Polyvinyl chloride resin molded products (a) are capable of eliminating surface cracks, (b) are able to maintain their shape, and (c) have chemical and physical properties. To provide a surface treatment method that does not damage. Means and Effects for Solving the Problems The method of the present invention involves treating the surface of a polyvinyl chloride resin molded product with low-temperature plasma, and then
It is characterized by heat treatment at a temperature of 100°C to 400°C and under normal pressure or under pressure. You can erase the barge. The polyvinyl chloride resins used in the method of the present invention include soft polyvinyl chloride resins, hard polyvinyl chloride resins, copolymer resins of vinyl chloride and olefins such as ethylene, propylene, or isobutylene, and vinyl chloride resins. and styrene, copolymer resins of vinyl chloride and dienes such as butadiene or isoprene, copolymer resins of vinyl chloride and acrylic acid, halogenated olefins, or vinyl acetate. , and the above resin and a modifying resin, for example,
There are mixed resins with rubber such as ABS, SBR, or NBR. The polyvinyl chloride resin may contain plasticizers, stabilizers, fillers, flame retardants, flame retardants, antioxidants, ultraviolet absorbers, antimicrobials, lubricants, pigments, etc. depending on the purpose. . There are no particular limitations on the shape and dimensions of the molded product to which the method of the present invention is applied, and the molded product may be a film, sheet, tape, or other molded product having the desired dimensions, and these molding methods may also be conventional methods. For example, any method such as a calendering method, an extrusion method, a coating method, or a dipping method may be used. There are no particular restrictions on the shape of the surface of the molded product, and the surface may be treated with an engraved roll having a desired pattern. In the method of the present invention, the polyvinyl chloride resin molded article is first subjected to low temperature plasma treatment. Low-temperature plasma treatment is generally carried out by exposing the surface of a polyvinyl chloride resin molded article to low-temperature plasma of a gas that does not have plasma polymerizability under a pressure of 0.01 to 10 Torr. The plasma treatment time varies depending on the applied voltage, but generally a range of several seconds to several minutes is sufficient. For low-temperature plasma treatment, for example, low frequency or microwave can be used as the discharge frequency band, and direct current can also be used, and the plasma generation mode can be glow discharge, corona discharge, spark discharge, silent discharge, etc. may also be used. Gases that do not have plasma polymerizability include helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, chlorine, hydrogen chloride, bromine cyanide, and bromine. Examples include halides such as tin oxide, and sulfides such as sulfur, sulfur dioxide, and hydrogen sulfide, and these gases can be used alone or in combination. Although such low-temperature plasma treatment alone does not have sufficient effect of erasing the surface of the molded product, the surface area treated with low-temperature plasma may be
When heat treatment at a temperature of 0.degree. C. is carried out under normal pressure or under pressure, a matting effect on the surface of the molded article is clearly manifested. Such a phenomenon was discovered for the first time in the present invention. Therefore, in the method of the present invention, the polyvinyl chloride resin molded product treated with low-temperature plasma is then subjected to heat treatment. Heat treatment is generally carried out under normal pressure or under pressure.
It is carried out at temperatures between 100°C and 400°C. In this heat treatment, it is sufficient that the surface portion subjected to the low-temperature plasma treatment is substantially heated to 100°C to 400°C,
For example, a molded product that has been subjected to low-temperature plasma treatment may be heated from its bottom surface, or it may be sandwiched between heating plates and contact pressure applied and heated from the surface of the molded product. Furthermore, it may be heated using high frequency or ultrasonic waves. It may also be heated internally. At a heating temperature of 100°C or lower, no erasing effect is observed, and at a heating temperature of 400°C or higher, the surface becomes rough and the shape of the molded product is impaired. Heating time varies depending on the heating temperature used, but generally a few seconds to an hour is sufficient; for example, 120℃ for about 50 minutes, 200℃ for about 20 seconds, and 300℃ for about 5 seconds. The heat treatment provides a sufficient erasing effect and does not damage the shape of the molded product or its surface. The heat treatment in the method of the present invention is performed under normal pressure or increased pressure. If the temperature is 100℃~400℃ under reduced pressure.
When heat treatment is carried out at a temperature of ℃, additives such as plasticizers in the molded product boil out and form ejection holes, which excessively roughens the surface of the molded product, changes its appearance and shape, and reduces its commercial value. This may cause problems such as significant damage to the It is still not clear why the fading effect, which was unclear only with low-temperature plasma treatment, appears when heat treatment is subsequently applied. However, this is probably because the heat treatment causes a difference in thermal stress between the crosslinked part and the non-crosslinked part produced by the low-temperature plasma treatment, resulting in the formation of fine irregularities that exhibit an erasing effect only in the very vicinity of the surface. Probably. Examples Hereinafter, the present invention will be further explained with reference to Examples. Example 1 Polyvinyl chloride resin composition having the following composition; Polyvinyl chloride (Kanevinyl S-1003)
100 parts by weight DOP 60 parts by weight Epoxidized soybean oil 3 parts by weight Ba-Zu stabilizer 2 parts by weight were heated at 160°C with heating rolls and kneaded for 10 hours.
The mixture was heated and kneaded for 1 minute, and formed into a film with a thickness of 0.3 mm. This is designated as sample 1 (untreated product). The test piece taken from this polyvinyl chloride film sample 1 was placed in a predetermined position in the low-temperature plasma device, the pressure inside the device was evacuated to 10 ^-5 Torr, and then CO gas was introduced into the device. pressure 0.2Torr
Adjusted to. Low temperature plasma treatment is frequency
Using a 13.56 MHz high frequency power supply (manufactured by Nippon Koshuha Co., Ltd.), the processing was performed at a power consumption of 100 watts, and the processing time was varied from 1 minute to 10 minutes as shown in Table 1. The sample that had been subjected to the low-temperature plasma treatment was then subjected to a heat treatment. The heat treatment was performed in a gear oven (manufactured by Toyo Seiki Seisakusho) at 180°C for 30 seconds. To determine the erasing effect of the obtained product,
This was done by visual observation using a magnifying glass. Judgment was based on the following criteria. In addition, the wear resistance properties were compared by the amount of wear loss using a Taber type abrasion tester (manufactured by Toyo Seiki Seisakusho). The results are shown in Table 1. (Judgment criteria for the enamel effect) 〇: The enamel effect is observed uniformly on the entire surface △: The enamel remains partially (in the recesses) ×: The enamel remains on the entire surface (Taper type abrasion test conditions) JISL-1096 C method According to Load: 250gr, Number of revolutions: 500 times Wear wheel H-18

[Table] For comparison, a sample that had been subjected to low-temperature plasma treatment was heat-treated at 180°C for 30 seconds in a vacuum chamber at 0.05 Torr. The product broke through and spouted out, forming many craters or voids on the surface, resulting in a product with poor appearance and could not be put to practical use. Example 2 Polyester base fabric with the following structure: 20/2 x 20/2/48 x 43 and polyvinyl chloride sol with the following composition: Polyvinyl chloride (Zeon 121) 100 parts by weight DOP 60 parts by weight Epoxidized soybean oil 3 parts by weight It was immersed in 2 parts by weight of Ba-Zu stabilizer, squeezed with a mangle, and heated at 190°C for 3 minutes to gel and fix the PVC resin. The amount of adhesion at this time was 250 g/m ² in terms of solid content. Without cooling this product, it was passed between an engraved roll having a floral pattern and a back roll to form a so-called diaphragm with a floral pattern on the surface of the PVC molded product. Sample 2
(unprocessed product). A test piece taken from this sample 2 was treated with low temperature plasma in the same manner as in Example 1. Here, Ar was used as the gas, the power consumption was 500 W, and the processing time was 30 seconds. In the heat treatment, the temperature was varied between 70°C and 450°C as shown in Table 2, and the treatment time was also varied between several seconds and one hour. The results are shown in Table 2.

[Table] As is clear from Table 2, by appropriately selecting the heating temperature and time in the method of the present invention,
It is possible to erase the surface while maintaining the shibori pattern. Effects of the Invention The method of the present invention can eliminate the unique burrs of polyvinyl chloride resin molded articles without impairing their physical and chemical properties. Particularly in molded products that have been subjected to drawing processing using engraved rolls having various patterns, it has become possible to erase the burlap without eliminating the surface pattern. As a result, polyvinyl chloride resin molded products can now be used in interior design and other applications, where until now their use was limited due to the unique properties of PVC.

Claims (1)

[Claims] 1. The surface of a polyvinyl chloride resin molded product is treated with low-temperature plasma, and then heated at 100°C to 400°C.
1. A method for surface modification of a polyvinyl chloride resin molded article, the method comprising heat-treating at a temperature of 100 mL and normal pressure or under increased pressure. 2. The method of claim 1, wherein the low temperature plasma treatment is carried out using low temperature plasma of a gas that does not have plasma polymerizability under a pressure of 0.01 to 10 torr. 3. The gas that does not have plasma polymerizability is helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide,
2. The method of claim 1, wherein the compound is selected from hydrogen, chlorine, halides and sulfides.