JPS6014773B2 - Manufacturing method for vinyl chloride resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a vinyl chloride resin molded article, and in particular, by modifying the surface properties of the molded article, plasticizers and other additives inside the molded article can be reduced. The present invention relates to a method for continuously preventing the phenomenon of migration and oozing onto the surface of a molded product over a long period of time.

PVC resin gives hard and rigid molded products when it is not blended with a plasticizer, but its hardness can be adjusted by blending a plasticizer such as phthalate, so it is suitable for use in rigid molded products. It is also widely applied not only to so-called soft molded products.

In addition to plasticizers, stabilizers, lubricants, antioxidants, chelators, dropless agents, ultraviolet absorbers, and Various additives and compounding agents such as fillers are used,
It is widely used in various products such as films, sheets, synthetic leather, tubes, hoses, bags, packing, and covering materials, including medical equipment, food packaging materials, electrical wire covering materials, agricultural materials, and construction materials. However, the plasticizers and other additives contained in these vinyl chloride resin molded products migrate to the molded product surface over time and ooze out, which can cause contamination of the appearance, deterioration of quality, and harmful effects. It is said to have major drawbacks in terms of (hygienic safety), durability, etc., and there is a problem that it is particularly limited in its application to medical and food applications.

As a countermeasure to these problems, it is possible to treat the surface of the molded product with ionizing radiation, ultraviolet rays, or chemical means, but when using such methods, heat resistance,
Although improvements in solvent resistance, hydrophilicity, antistatic properties, and printability are achieved to some extent, it is not only impossible to prevent the oozing of plasticizers, etc., but also the inherent properties of vinyl chloride resin are diminished. There are disadvantages such as being left behind.

In other words, since the energy of ionizing radiation treatment is too strong, it acts not only on the surface of the molded product but also to some extent inside the molded product, causing intermolecular cross-linking reactions, which greatly deteriorates the original properties of vinyl chloride resin. In addition, ultraviolet treatment has the problem of discoloration due to decomposition and deterioration of the surface of the molded product, and furthermore, when using chemical means, there are problems with corrosion of the molded product and problems with the adhesion and durability of the treatment agent. On the other hand, attempts have been made to modify the surface of plastic molded products by subjecting them to low-temperature plasma treatment. However, if it is exposed outdoors for a long period of time, the preventive effect will disappear over time, resulting in poor weather resistance and durability.

As a result of extensive research into this technical problem, the present inventors have found that when a vinyl chloride resin molded product containing a predetermined amount of a methacrylic group-containing compound is treated with low-temperature plasma, intermolecular crosslinking on the surface of the molded product progresses favorably. The present invention has been completed based on the discovery that this can continuously prevent additive components such as plasticizers from oozing out onto the surface of the molded product over a long period of time.

That is, in the present invention, a vinyl chloride resin composition containing 0.5 to 50 parts by weight of a methacrylic group-containing compound per 10 parts by weight of vinyl chloride resin is molded, and then this molded product is heated to 0.001 Torr. The present invention relates to a method for manufacturing a vinyl chloride resin molded article, which is characterized in that it is treated with low-temperature plasma of a gas that does not have plasma polymerizability under a pressure of ~10 torr.

The present invention will be explained in detail below. The pinyl chloride resin used in the method of the present invention may be either polyvinyl chloride or a copolymer mainly composed of vinyl chloride, and examples of the comonomer copolymerized with vinyl chloride include vinyl ester, vinyl ether, Examples include acrylic acid or methacrylic acid and its esters, maleic acid or fumaric acid or anhydride, and its esters/aromatic vinyl compounds, vinylidene halides, acrylonitrile or methacrylonitrile, and olefins such as ethylene and propylene.

In addition, a methacrylic group-containing compound is used as an essential component, and this has the effect of promoting crosslinking reaction on the surface of the molded product by low-temperature plasma treatment, which prevents the oozing out of plasticizers, etc. It is effective in reducing usage, improving the flexibility of molded products, and improving the smoothness and aesthetic appearance of molded product surfaces.

The methacrylic group-containing compound used for this purpose may be any compound having one or more methacrylic groups in one molecule, such as methyl methacrylate, lauryl methacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, etc. Examples include methacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate.

However, among these, those having two or more methacrylic groups are particularly desirable. The above tacryl group-containing compound needs to be used in a range of 0.5 to 5 parts by weight per 10 parts by weight of the vinyl chloride resin, and if this is too small, the effect of the low-temperature plasma treatment described above becomes small, and if it is too large, it becomes impossible to obtain a molded product with the performance inherent to vinyl chloride resin.

The vinyl chloride resin composition used in the method of the present invention is
In addition to containing the above-mentioned methacrylic group-containing compound as an essential component, it also contains various necessary additives and compounding agents.

For example, as a plasticizer used to adjust the flexibility and hardness of molded products, jetyl phthalate, di-2 phthalate, etc.
- Phthalic acid esters such as ethylhexyl and dinonyl phthalate, trimellitic acid esters such as trimethyl trimellitate and trioctyl trimellitate, aliphatic dibasic acid esters such as dioctyl adipate, diisodecyl adipate, and dioctyl azelate, oleic acid butyl,
Fatty acid esters such as methyl acetyl lysylate, chlorinated fatty acid methyl, ethyl phthalyl ethylene glycolate,
Examples include plasticizers such as diethylene glycol dibenzoate and tributyl acetyl citrate.

In addition, additives used to improve properties such as heat resistance, toughness, and stability include calcium stearate, zinc stearate, lead stearate, barium stearate,
Consisting of metal salts of carboxylic acids such as cadmium stearate, tribasic lead sulfate, dibasic lead phosphite, organic tin compounds such as dibutyltin dilaurate, di-n-octyltin maleate, and di-n-octyltin mercaptide. Stabilizers; esters such as butyl stearate,
fatty acid amides, such as ethylene bisstearamide,
Silk agents made of higher fatty acids and their esters, or polyethylene wax; Other various additives used in molding vinyl chloride resins, such as fillers, antioxidants,
Examples include ultraviolet absorbers, antistatic agents, antifogging agents, pigments, and dyes.

The pinyl chloride resin composition used in the method of the present invention includes:
For the purpose of improving the physical properties of the molded product, an elastic polymer rubber may be blended, and examples of the elastic polymer include ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, and styrene-acrylonitrile copolymer. Examples include ethylene propylene elastomer, ethylene-propylene diene elastomer, and the like.

In addition, these are 5 parts by weight per 10 vinyl chloride resins.
It is desirable to use the compound in an amount of not more than 1 part by weight. In the method of the present invention, the vinyl chloride resin composition obtained in this way is first molded into a molded product, and this molding method can be performed by extrusion molding, injection molding, calendar molding, inflation molding,
Any molding method conventionally employed in molding vinyl chloride resin, such as compression molding, may be used, and there are no particular restrictions on the type or shape of the molded product.

Next, this molded article is subjected to low temperature plasma treatment, and this treatment may be performed by treating the molded article with low temperature plasma of a gas that does not have plasma polymerizability under a pressure of 0.001 to 10 torr. In this case, the plasma generation conditions include, for example, a ratio of 13.5 between the electrodes, and a ratio of 10 to 10.
It is sufficient to apply a power of 500 W, and sufficient results can be obtained whether the discharge is a polar discharge or an electrodeless discharge.

The plasma processing time varies depending on the applied voltage, but generally a few seconds to several tens of minutes is sufficient. In addition,
There are various methods for plasma treatment other than the above-mentioned method. For example, low frequency, microwave, direct current, etc. can be used as the discharge frequency band, and plasma generation modes include glow discharge, corona discharge, spark discharge, and silent discharge. You can choose discharge, etc.

In addition to external electrodes, the electrodes may also be internal electrodes, coil type, or other capacitively coupled electrodes. However, no matter what method is used, it is necessary to prevent the surface of the material from deteriorating due to discharge heat. Gases that do not have plasma polymerizability include helium, 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 are used alone or in combination.

By setting the gas pressure of these gases in the plasma generator to 0.001 to 10 Torr (preferably 0.01 Torr to 1 Torr), the desired plasma can be generated satisfactorily. By plasma-treating the molded product in this way, the phenomenon of additives such as plasticizers oozing out onto the surface of the molded product is completely suppressed, and the formed surface treatment layer (barrier layer) has flexibility. In addition, the air fill density is appropriately controlled, so it has good heat sheet properties and durability, and the barrier layer remains intact even when the molded product is used outdoors for a long period of time. The result is a molded product with remarkable durability and full functionality.

Furthermore, this plasma-treated molded product exhibits excellent surface properties such as hydrophilicity, camphor resistance, oil resistance, and chemical resistance. Next, examples of the present invention will be given.

Example 1 A mixture consisting of 10 parts by weight of vinyl chloride resin (TK-1300, trade name manufactured by Shin-Etsu Chemical Co., Ltd.), parts by weight of DOP5, 1.5 parts by weight of calcium stearate, and 1.5 parts by weight of zinc stearate was mixed into 160 oo The mixture was kneaded with a roll for 10 minutes, and then press-molded using 16520 to form a sheet with a thickness of 0.5 mm.

This is designated as sample A-1. Further, a mixture of the above-mentioned compound and other parts by weight of diethylene glycol dimethacrylate was mixed and press-molded in the same manner as above to a thickness of 0.
I created a sheet for the 5th side. This is designated as sample B-1. 13. Set each of the sheets of Samples A-1 and B-1 in a plasma generator, and adjust and maintain the pressure at 0.4 torr while passing carbon monoxide gas under reduced pressure.13. Handling ratio, 15
Plasma was generated by applying a high frequency wave of 0 W and causing discharge, and the sheet surface was treated for 10 minutes. The sheets treated with plasma in this manner are designated as A-2 and B-2. For each of the above samples, the initial n-hexane extraction amount and the n-hexane extraction amount after forced deterioration were measured using a weather meter, and the results were as follows.

(N-hexane extracted amount of phosphorus) Sample name A-IA-2 B-I B-2 Initial value 156 1.04 143 0.78 forced deterioration ・3o 3.9100 hours forced deterioration ・43 13.0500 hours n -Measurement method for hexane extraction amount: A sample sheet was set at the bottom of a 100°C cylindrical extraction container, the surface of this 26-layer was brought into contact with 50'N-hexane, and the sample sheet was heated in a water bath at 30°C. So we played monkey games for 2 hours.
The amount of plasticizer (DOP) extracted into n-hexane was quantitatively analyzed by gas chromatography.

Forced deterioration test method using a weather meter: Standard Sunsayain Weather Ometer WESUNHC model (manufactured by Toyo Rika Co., Ltd.) was used to force deterioration for 10 or 50 hours.

Example 2 100 parts by weight of vinyl chloride resin (TK-1300), DO
Parts by weight of P5, 1.5 parts by weight of calcium stearate,
160% of a formulation consisting of 1.5 parts by weight of zinc stearate
℃ for 1 minute, and then press-molded at 165q0 to produce a sheet with a thickness of 0.5 mm.

This is designated as sample A-1. Further, 1 part by weight of trimethylolpropane trimethacrylate was added to the above-mentioned mixture, and the mixture was thickened and press-molded under the same conditions as above to prepare a sheet having a thickness of 0.5.

This is designated as sample B-1. Above samples A-1 and B-1
Each sheet was set in a plasma generator, and the pressure was adjusted and maintained at 0.8 torr while venting carbon monoxide and argon mixed gas (10:90) under reduced pressure.
, 300 W of high frequency was applied and discharged to generate plasma, and the sheet surface was treated for 5 minutes.

The sheets processed in this way are referred to as A-2 and B-2. For each of the above samples, the initial amount of n-hexane extracted and the amount of n-hexane extracted after forced deterioration due to outside Weathermey were measured using the same machine as the previous example, and the results were as follows.

(N-hexane extraction amount) Sample name A-I A-2 B
-I B-2 initial value 156
1.30 143 078
Forced deterioration 13o
l. 56100 hours forced deterioration

5.2500 hours Example 3 100 parts by weight of pinyl chloride resin (TK-1300), DO
P50 parts by weight, calcium stearate 1.5 parts by weight,
160% of a formulation consisting of 1.5 parts by weight of zinc stearate
The mixture was kneaded with a roll for 10 minutes at OO, and then press-molded at 165q0 to produce a sheet with a thickness of 0.5.

This will be referred to as sample A-1. Further, 15 parts by weight of diethylene glycol dimethacrylate was added to the above-mentioned mixture, and the mixture was kneaded and press-molded under the same conditions as above to prepare a sheet having a thickness of 0.5 mm.

This is designated as sample B-1. Above samples A-1 and B-1
Each sheet is set in a plasma generator, the pressure is adjusted and maintained at 0.15 Torr while carbon monoxide gas is vented under reduced pressure, and a high frequency of 13.58M and 500W is applied to generate plasma. was generated and the sheet surface was treated for 5 minutes. The sheets processed in this way are referred to as A-2 and B-2. The initial n-hexane extraction amount and the n-hexane extraction amount after outdoor exposure were measured for each of the above samples, and the results were as follows.

(n-hexane extract)

Claims (1)

[Claims] 1. A vinyl chloride resin composition containing 0.5 to 50 parts by weight of a methacrylic group-containing compound per 100 parts by weight of vinyl chloride resin is formed, and then this molded product is
1. A method for producing a vinyl chloride resin molded article, which comprises treating the product with low-temperature plasma of a gas that does not have plasma polymerizability under a pressure of 0.01 to 10 Torr.