JPS6059252B2 - Surface treatment method for vinyl chloride resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of vinyl chloride resin molded articles, and in particular, to provide permanent antistatic properties to the molded articles by modifying the surface properties of the vinyl chloride resin molded articles. The purpose of this is to impart properties such as durability and stain resistance.

In general, vinyl chloride resin molded products are easily charged with electricity, so the appearance becomes dirty due to adhesion of dust, dirt, etc., and problems such as the effects on the human body due to accumulated static electricity (lightning shock) and spark discharge. have.

Known methods for preventing this charging (accumulation of static electricity) include applying an antistatic agent to the surface of the molded product or incorporating an antistatic agent into the molded product during manufacture. The former method of application provides a fast-acting effect, but lacks durability and has the problem of a sticky surface and blocking, while the latter method has less durability than the former method. However, the antistatic effect is not sufficient, and when the amount of antistatic agent added to compensate for this, a sticky feeling appears on the surface of the molded product, causing problems such as blooming and blocking. However, there are disadvantages in that heat resistance decreases, processability deteriorates, and the surface of the molded product is easily colored and stained.

On the other hand, attempts have been made to improve the hydrophilicity of vinyl chloride resin molded articles by plasma-treating their surfaces and thereby suppress charging, but sufficient effects cannot be obtained.

The inventors of the present invention conducted extensive research to solve these problems, and found that they exposed vinyl chloride resin molded products to low-temperature plasma of an organic compound containing nitrogen atoms at 10 torr or less, and then applied halogen or halogen to the low-temperature plasma-treated surface. When a molded product is brought into contact with hydrogen hydride or an organic halide, its surface properties are modified without sacrificing its inherent mechanical strength, giving it excellent antistatic properties and stain resistance. I discovered that. Furthermore, when treated with the above method, an extremely thin modified layer is formed on the surface of the vinyl chloride resin molded product, and this layer has the advantage of bonding particularly strongly to polyvinyl chloride. The formation speed was faster than that of other polymer molded products, and it was confirmed that the effects of low-temperature plasma treatment were noticeable. The nitrogen atom-containing organic compound is preferably a compound represented by the general formula.

In the above general formula, R1 represents a substituted or unsubstituted monovalent hydrocarbon group, and R2, R3, R5 and R6 represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, respectively. However, in the present invention, organic compounds having silicon atoms are not included.

The present invention will be explained in detail below.

The vinyl chloride resin molded products targeted by the method of the present invention mainly include polyvinyl chloride and vinyl chloride. In this case, the comonomer copolymerized with vinyl chloride may be vinyl ester, vinyl ether, acrylic acid or methacrylic acid and its ester, maleic acid or fumaric acid, or its - Examples include esters, maleic anhydride, aromatic vinyl compounds, vinylidene halides, acrylonitrile or methacrylonitrile, and olefins such as ethylene and propylene.

Note that various compounding agents and additives may be added to the vinyl chloride resin as necessary. For example, plasticizers used to adjust the flexibility and hardness of molded products include phthalate esters such as dioctyl phthalate, dibutyl phthalate, butylbenzyl phthalate, dioctyl adipate,
Aliphatic dibasic acid esters such as dibutyl sebacate, glycol esters such as pentaerythritol ester and diethylene glycol dibenzoate, fatty acid esters such as methyl acetyl ricinoleate, phosphate esters such as tricresyl phosphate and triphenyl phosphate, and epoxy Epoxidized oils such as oxidized soybean oil and epoxidized linseed oil, citric acid esters such as acetyl tributyl citrate and acetyl trioctyl citrate, trialkyl trimellitate, tetra n-octyl pyromellitate, polypropylene adipate, and other polyesters. Examples include plasticizers with various structures such as.

In addition, as additives used to improve properties such as lubricity and stability, metal salts of carboxylic acids such as calcium stearate, zinc stearate, lead stearate, barium stearate, and cadmium stearate, tribasic Lead sulfate, dibasic lead phosphite, dibutyltin dilaurate,
Organic tin compounds such as di-n-octyltin malate and di-n-octyltin mercaptite, esters such as butyl stearate, fatty acid amides such as ethylene bisstearamide, higher fatty acids and their esters, or polyethylene Wax etc. are exemplified.

Various other additives used in the molding of vinyl chloride resins include fillers, heat resistance improvers, antioxidants, ultraviolet absorbers, antistatic agents, anti-drop agents, pigments, dyes, crosslinking aids, etc. Ru. Furthermore, various polymeric rubber elastic bodies may be blended, and examples of this polymeric comb elastic body include ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, styrene-acrylonitrile copolymer, and methyl methacrylate copolymer. Examples include styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, urethane elastomer, polyamide resin, ethylene-propylene-diene terpolymer, and epoxy-modified polybutadiene resin.

It is desirable to use these in an amount of 5 parts by weight or less per 10 parts by weight of the vinyl chloride resin. The method for obtaining a vinyl chloride resin molded product may be any conventional molding method used for molding vinyl chloride resin, such as extrusion molding, injection molding, calendar molding, inflation molding, or compression molding, depending on the type of molded product. , there are no particular restrictions on the shape. In the method of the present invention, the surface of the vinyl chloride resin molded article thus obtained is treated with low-temperature plasma of a nitrogen atom-containing organic compound. Preferably, those represented by the following general formulas include methylamine, dimethylamine, trimethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, and n-propylamine.
-Butylamine, n-amylamine, n-hexylamine, laurylamine, ethylenediamine, trimethylenediamine, hexamethylenediamine, ethanolamine, diethanolamine, allylamine, aniline, alanine, N-methylaniline, allyldimethylamine, 2
-aminoethyl ether, 1-dimethylamino-2-chloroethane, cyclopropylamine, cyclohexylamine, ethyleneimine, 1-methylethyleneimine, formamide, N,N-dimethylformamide, capronamide, aminoacetal, benzylamine, piperidine, Amines such as pyrrolidine and morpholine, imines,
Amides, imides, and derivatives thereof are exemplified.

Among these compounds, those having a high boiling point (low vapor pressure) may be used in a gaseous state by heating or other operations. When generating a low-temperature plasma of a nitrogen atom-containing organic compound, the pressure of the nitrogen atom-containing organic compound in the device is often 10-3 to 10 Torr (preferably 0.01 Torr to 5 Torr). A low-temperature plasma can be generated satisfactorily.

Therefore, the nitrogen atom-containing organic compound may be one having a vapor pressure that allows it to exist as a gas at such a pressure, and therefore those having a relatively large molecular weight can also be used. In addition to using one type or two or more types of nitrogen atom-containing organic compounds, these nitrogen atom-containing organic compounds may be used in combination with an inorganic gas, and examples of this inorganic gas include helium, neon, argon, and nitrogen. , nitrous oxide, nitrogen monoxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, bromine cyanide, sulfur dioxide gas, hydrogen sulfide, etc. These gases may be used alone or in combination. Ru.

The gas pressure of these gases in the plasma generator (
It is desirable that the partial pressure (partial pressure) be 1110 or less of the partial pressure of the nitrogen atom-containing organic compound, or 0.5 torr or less, so that the desired low-temperature plasma can be generated better. be able to. The conditions for generating low-temperature plasma include, for example, applying high frequency power of several KHz to several hundred MHz between the electrodes, and sufficient results can be obtained with either polar discharge or 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.For example, low frequency, microwave, direct current, etc. can be used as the discharge frequency band, and the electrodes can be capacitively coupled, such as internal electrodes, coil type, etc. in addition to external electrodes. or inductive coupling.

However, whatever method is used, it is necessary to prevent the surface of the material from deteriorating due to discharge heat. In the method of the present invention, after a vinyl chloride resin molded article is subjected to low-temperature plasma treatment as described above, the treatment is completed by bringing the treated surface into contact with halogen, hydrogen halide, or a halide. Examples of hydrogen halides include fluorine, chlorine, bromine, and iodine, and hydrogen halides include hydrogen chloride, hydrogen bromide, hydrogen iodide, and hydrogen fluoride. Examples of organic halides include n-propyl fluoride, methyl chloride, methyl bromide, allyl chloride, vinyl chloride, vinyl bromide, isopropenyl chloride, 1,1,2-
Examples include trifufluorinated ethane, 1,1-dichloroethane, chloroform, and carbon tetrachloride. The means for bringing the halogen, hydrogen halide, or organic halide into contact with the low-temperature plasma-treated surface of the molded article may be either gaseous contact or liquid contact. In gaseous contact, for example, bromine, iodine, allyl chloride, chloroform, carbon tetrachloride, etc. may be made gaseous by heating and/or reduced pressure, and then the contact operation is performed, while in liquid contact, for example, fluorine, hydrogen fluoride, Chlorine, hydrogen chloride, hydrogen bromide, hydrogen iodide, methyl chloride, vinyl chloride, etc. may be liquefied by cooling and/or under pressure and then subjected to a contact operation. In consideration of the contact operation and the removal of excess contact material after the contact is completed, gaseous contact, so-called dry contact treatment is desirable. In this case, it is preferable for the contact pressure to be 10 torr or more in terms of processing efficiency, and the contact time varies depending on the pressure, gas temperature, temperature of the molded product surface, etc., but is usually from several tens of seconds to several tens of minutes. This allows the desired modification to occur. The vinyl chloride resin molded product treated by the method of the present invention does not lose any of its original physical properties such as mechanical strength, but has the above-mentioned antistatic properties and stain resistance due to surface modification. In addition, it has other advantages such as excellent abrasion resistance, adhesion, heat resistance, wettability, and printability.

Next, specific examples will be given.

Experiment No. l 10 parts by weight of vinyl chloride resin, 1 part by weight of DOPl, 1 part by weight of dibutyltin mercaptide, 0.0 parts by weight of calcium stearate. A blend of heel weight, 0.3 parts by weight of zinc stearate, and 1 part by weight of epoxidized soybean oil was kneaded with a roll at 170°C, and then press-molded at 175°C to a thickness of 0.
．． A sheet of 5Tf$t was created (unprocessed sheet).

This sheet was set in a plasma generator, and after evacuating the inside of the apparatus to 10<-6> Torr, nitrogen gas was introduced and the inside of the apparatus was adjusted and maintained at 0.1 Torr while the gas was flowing. Next, ethylamine gas was introduced into the device, mixed with nitrogen gas, and the temperature inside the device was adjusted to 0.3 Torr under gas flow. Adjust and hold; 13.
High-frequency power of 56 MHz and 1 KW was applied to generate low-temperature plasma, and the sheet was treated for 3 minutes (treated sheet 1).

After that, the pressure inside the apparatus was reduced to 10-3 Torr, and then chlorine gas was introduced, and when the internal pressure reached 100 Torr, it was introduced. The heating was stopped and the sheet was left under 100 Torr for 5 minutes to contact the sheet with chlorine gas (treated sheet 2).

When the tobacco ash adsorption distance, surface resistivity, and frictional charging voltage were measured for sheets 1 and 2 treated in this manner and sheets that were not treated, the following results were obtained. Experiment No. 2 Experiment No. Using the same molded sheet as in I, set this sheet in a plasma generator, evacuate the inside of the device to 10-6 torr, then introduce argon gas and adjust the inside of the device to 0.6 torr while circulating. held.

Next, ethylamine gas was introduced into the apparatus, and while being mixed with argon, the inside of the apparatus was adjusted and maintained at 1.2 torr. A high frequency power of 13.56 MHz and 800 W was applied to this system to generate low temperature plasma, and the sheet was treated for 5 minutes. After that, the treated sheet was taken out, placed in a vacuum device, and the pressure was reduced to 1 Torr, then chlorine gas was introduced, and when the internal pressure reached 100 Torr, the introduction was stopped, and the sheet was left under 100 Torr for 10 minutes to be brought into contact with the chlorine gas. Ta.

Regarding this treated sheet, experiment No. The physical properties were measured in the same manner as 1, and the results were as follows. Experiment No. 3. A blend consisting of 10 parts by weight of vinyl chloride resin, 2.5 parts by weight of lead stearate, 0.5 parts by weight of tribasic lead sulfate, 0.5 parts by weight of barium stearate, and 0.3 parts by weight of polyethylene wax. Knead with a roll for 10 minutes at 180°C,
This was press-molded at 185° C. to produce sheets of one thickness.

This sheet was set in a plasma generator, and after the inside of the apparatus was evacuated to 10<-6> Torr, carbon dioxide gas was introduced and the inside of the apparatus was adjusted and maintained at 0.05 Torr while gas was flowing.

Next, allylamine gas was introduced into the device, and while mixing with carbon dioxide gas, the inside of the device was adjusted and maintained at 1 Torr.
High frequency power of MHz 1 KW was applied to generate low temperature plasma and the sheet was treated for 5 minutes. Afterwards, check the inside of the device by 10-3.
After reducing the pressure to 450 torr, hydrogen chloride gas was introduced to
When the temperature reached a certain level, the introduction was stopped and the sheet was left standing for one hour, and the sheet was brought into contact with hydrogen chloride gas.

Experiment No. 1 was obtained for sheets treated in this manner and sheets not subjected to plasma treatment. The physical properties were measured in the same manner as in 1, and the results were as shown below.

Experiment No. 4 Using the same sheet as in Experiment No. 3, set this sheet in the plasma generator, reduce the pressure inside the device to 10-6 Torr, then introduce carbon dioxide gas, and reduce the pressure inside the device to 0.7 Torr under gas flow.
Adjusted and held to the torque.

Next, allylamine gas was introduced into the device, mixed with carbon dioxide gas, and the inside of the device was adjusted and maintained at 1.7 Torr.
High-frequency power of MHz 1 KW was applied to generate low-temperature plasma, and the sheet was treated for 5 minutes.

Regarding this treated sheet, experiment No. The physical properties were measured in the same manner as in 1, and the results were as follows. Experiment No. 5 Experiment No. Using the same molded sheet as in Example 3, this sheet was set in a plasma generator and the pressure inside the apparatus was reduced to 10<-6> Torr, and then argon gas was introduced to adjust and maintain the inside of the apparatus at 0.05 Torr.

Next, dimethylamine gas was introduced into this device, and while mixing with argon, the inside of the device was adjusted and maintained at 0.08 Torr.
A high frequency power of 0 KHz and 2 KW was applied to generate low temperature plasma and the sheet was treated for 2 minutes. After that, take out the treated sheet, put it in a vacuum device, reduce the pressure to 100 Torr, introduce chlorine gas, and stop introducing it when the internal pressure reaches 15 Torr.
The sheet was allowed to stand for a minute and was brought into contact with chlorine gas.

Regarding this treated sheet, experiment No. The physical properties were measured in the same manner as 1, and the results were as follows.

Experiment No. 6 Experiment No. Using the same sheet as in 3, set this formed sheet in a plasma generator, reduce the pressure inside the device to 10-6 torr, then introduce nitrogen gas and adjust the inside of the device to 0.3 torr under gas flow. held.

Next, dimethylformamide gas is introduced into the device and mixed with nitrogen gas while adjusting and maintaining the inside of the device at 0.4 torr.
High frequency power of 13.56 MHz 2 KW was applied to generate low temperature plasma and the sheet was treated for 3 minutes. After that, the treated sheet was taken out, put into a decompression device, and the pressure was reduced to 0.1 Torr, then heated allyl chloride gas was introduced, the internal pressure was set to 76 degrees, and it was left for 1 minute, and the silt was brought into contact with allyl chloride. I let it happen. Regarding this treated sheet, experiment No. The physical properties were measured in the same manner as 1, and the results were as follows.

Experiment No. 7 Consisting of 10 parts by weight of vinyl chloride-vinyl acetate copolymer (SC-400G: Shin-Etsu Chemical Co., Ltd.), 3 parts by weight of dibutyl tin mercaptide, 2 parts by weight of epoxidized soybean oil, and 0.5 parts by weight of calcium stearate. The mixture was heated to 180°C.
The mixture was kneaded with one powder roll and press-molded at 185°C to form a sheet with a thickness of 1Tn.

Claims (1)

[Claims] 1. A vinyl chloride resin molded product is exposed to low-temperature plasma of a nitrogen atom-containing organic compound (excluding organic silicon compounds) at 10 torr or less, and then halogen or hydrogen halide is applied to the low-temperature plasma-treated surface. Alternatively, a method for surface treatment of a vinyl chloride resin molded article, which comprises contacting with an organic halide. 2 The nitrogen atom-containing organic compound has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (in the formula, R^1 is a substituted or unsubstituted monovalent hydrocarbon group, R^2 and R^3 are hydrogen atoms or a substituted or unsubstituted monovalent hydrocarbon group). 3 The nitrogen atom-containing organic compound is a compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^5 and R^6 are hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups) A surface treatment method according to claim 1. 4. The gas atmosphere of the low-temperature plasma is composed of (a) a nitrogen atom-containing organic compound with a gas partial pressure of 10^-^3 to 10 Torr, and (b) an inorganic gas with a gas partial pressure of 10^-^4 to 10 Torr. The surface treatment method according to claim 1, characterized in that: