JPS6059929B2 - 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 products, and in particular, it provides permanent antistatic properties to molded products by modifying the surface properties of vinyl chloride resin molded products. 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 the adhesion of dust, dirt, etc., and problems such as the effects on the human body due to accumulated static electricity (electric 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 quick-acting effects, but lacks durability and has the problem of sticky and blocking surfaces, while the latter method is more durable than the former. Although the antistatic effect is excellent, the antistatic effect is insufficient, 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, as well as poor heat resistance. There are disadvantages in that the 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.

In order to solve this problem, the inventors of the present invention have conducted extensive research, and as a result, we have developed vinyl chloride resin molded products with gas partial pressures of 10-2 to 10-2.
Low-temperature plasma treatment is performed by applying high-frequency power of 10 KHz or more between electrodes in an atmosphere of 10 torr of nitrogen atom-containing organic compounds (excluding organosilicon compounds) and inorganic gas with a gas partial pressure of 10-4 to 10 torr. In addition, by providing a polymer film of the nitrogen atom-containing organic compound on the surface of the molded product, the surface properties of the molded product are modified without impairing its inherent mechanical strength, resulting in excellent antistatic properties and durability. It has been found that it imparts contaminant properties. 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 strongly bonding to polyvinyl chloride, and the formation speed of this modified layer is It was confirmed that the processing speed was faster than that of other polymer molded products, and the effects of low-temperature plasma treatment were noticeable. It is particularly desirable that the nitrogen atom-containing organic compound is a compound represented by the general formula or.

In the above general formula, R1 is a substituted or unsubstituted monovalent hydrocarbon, R29R39R49R59R69R79R99
RlO and Rll represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, and R8 represents a substituted or unsubstituted divalent hydrocarbon group, respectively. In addition, preferable results can be obtained by coexisting nitrogen, a nitrogen atom-containing organic compound, or a rare gas together with the above-mentioned nitrogen atom-containing organic compound in the low-temperature plasma atmosphere, and further, low-temperature plasma can be generated by high-frequency discharge of 10 KHz or higher. Furthermore, by applying high-frequency power between electrodes installed in a gas atmosphere containing nitrogen-containing organic compounds to generate low-temperature plasma, it is possible to achieve better and more durable antistatic and anti-pollution properties. can be given gender.

It should be noted that the method of manufacturing a plasma-polymerized semipermeable membrane using an amine monomer and an electrodeless (external electrode) method of high-frequency discharge is well known, but if an internal electrode is used for such plasma polymerization, the formation Plasma polymerization treatment using conventional polymer-based polymers using internal electrodes has been considered due to disadvantages such as deterioration of the film, peeling of the film from the substrate, and non-uniform film thickness. It had not been done.

On the other hand, studies have not yet been conducted on applying plasma polymerization to a high-frequency base material using an electrodeless method to impart antistatic properties. When a vinyl chloride resin molded product is subjected to plasma polymerization treatment, a polymer film of the nitrogen atom-containing compound is formed on the base material, and usually only a strongly positively charged molded product is obtained, but no antistatic effect is obtained. No (untreated vinyl chloride resin molded products are usually strongly negatively charged).

However, by using the internal discharge method using high-frequency power as in the present invention, a modified vinyl chloride resin molded product having extremely good antistatic properties can be obtained.

Although the reason for this is not clear, it can be estimated as follows. In other words, in the internal electrode method, unlike the electrodeless method, the growth reaction of the polymer film, the deterioration and decomposition reactions of the film and the base material are considerably faster, and the polymer film covers the surface of the molded product on the base material evenly.
In other words, rather than a reaction mainly consisting of a polymerization reaction between amine or amide compounds, a comparatively low molecular weight nitrogen atom-containing compound or the amine or amide compound used itself is introduced as a functional group into the surface layer of the base material. In other words, the bonding reaction between the amine or amide compound and the base material is preferential,
As a result, the introduced functional group, which tends to be positively charged, and the vinyl chloride polymer portion, which tends to be negatively charged, can cancel each other out. The present invention will be explained in detail below.

The vinyl chloride resin molded article targeted by the method of the present invention may be manufactured from polyvinyl chloride or a copolymer mainly composed of vinyl chloride, and in this case, the comonomer to be copolymerized with vinyl chloride is are vinyl esters, vinyl ethers, acrylic acid or methacrylic acid and its esters, maleic acid or fumaric acid or its esters, maleic anhydride, aromatic vinyl compounds, vinylidene halides, acrylonitrile or methacrylonitrile, as well as ethylene, propylene, etc. Examples include olefins.

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, pentaerythritol esters, glycol esters such as diethylene glycol dibenzoate, aliphatic esters such as methyl acetyl ricinoleate, phosphate esters such as tricresyl phosphate and triphenyl phosphate, 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. is 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, such as ethylene-vinyl acetate copolymer, acrylonitrile-butadiene copolymer, styrene-acrylonitrile copolymer, methyl methacrylate copolymer, etc. 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 of 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, and 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, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, 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-
Chlorethane, cyclopropylamine, cyclohexylamine, ethyleneimine, 1-methylethyleneimine,
Examples include amines, imines, amides, amides, and derivatives thereof, such as formamide, N,N-dimethylformamide, capronamide, aminoacetal, benzylamine, piperidine, pyrrolidine, and morpholine.

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 need only have a vapor pressure that allows it to exist as a gas at such a pressure, and therefore compounds with relatively large molecular weights 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 (
The partial pressure) is desirably 1110 or less of the partial pressure of the nitrogen atom-containing organic compound, or 0.5 torr or less. By doing so, the desired low-temperature plasma can be generated well. can. 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 or non-electrode 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 processing 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 external electrodes, internal electrodes, capacitive coupling such as coil type, Either inductive coupling may be used.

However, no matter what method is used, it is necessary to prevent the surface of the material from deteriorating due to discharge heat. Although it is preferable to carry out the method of the present invention using an internal electrode method, there is no particular restriction on the shape of the electrode in this case;
The input side electrode) and the ground side electrode may have the same shape or different shapes, and they can be in various shapes such as a flat plate, a mesh, a coil, a ring, and a rod. It is also possible to use a method in which the electrode is a high frequency electrode or a ground side electrode. The vinyl chloride resin molded product treated by the method of the present invention does not lose any of its inherent physical properties such as mechanical strength, and has the above-mentioned antistatic properties and stain resistance due to surface modification. In addition, it has other advantages such as excellent abrasion resistance, adhesiveness, heat resistance, wettability, and printability.

Next, specific examples will be given.

Experiment. 1 1 A blend consisting of 10 parts by weight of vinyl chloride resin, 5 parts by weight of plasticizer (DOP), 2 parts by weight of barium-zinc stabilizer, and 3 parts by weight of epoxidized soybean oil was kneaded with one powder roll at 170°C, This was press molded at 175℃ to a thickness of 0.3T1.
n sheets were created.

This sheet is installed between the internal electrodes in the plasma generator (between the high frequency flat plate electrode and the earth flat plate electrode), and the inside is
After reducing the pressure to 0-4 Torr, ethylamine gas was introduced, and after adjusting and maintaining it at 0.1 Torr under gas flow, 13 Torr was applied between the internal electrodes.
．． A high-frequency power of 56 MHz and 500 W was applied to generate low-temperature plasma, and the sheet was subjected to low-temperature plasma treatment for 3 minutes (this treated sheet is referred to as treated sheet (2)).

In addition, in the above, the flow pressure of ethylamine gas was set to 5×1.
A low-temperature plasma treatment was performed in the same manner except that the temperature was changed to 0-4 torr (this treated sheet is referred to as treated sheet I). When the tobacco ash adsorption distance, surface resistivity, and frictional charging voltage were measured for sheets I and (2) treated in this manner and sheets that were not subjected to plasma treatment, the following results were obtained.

*1: After rubbing the sample surface with a cotton cloth 10], bring it close to cigarette ash and the cigarette ash begins to adhere to it.Experiment No. 10 parts of vinyl dichloride resin, 3 parts of dimethyltin mercaptide
1 part by weight, 1 part by weight of epoxidized soybean oil, and 0.5 parts by weight of ethylene bisstearylamide.
The powder was kneaded with one roll at 75℃ and then press-formed at 180℃ to a thickness of 0.2Tfr! A sheet of Ft was created.

Experimented with this sheet. Using the same equipment and electrodes as in 1, after installing the sheet between the electrodes, the pressure inside the equipment was reduced to 10-4 Torr, and then dimethylformamide gas was introduced.
A high-frequency power of 13.56 MHz and 1 KW was applied to the gas under 0.5 torr to generate low-temperature plasma, and the formed sheet between the electrodes was treated for 3 minutes.

In this way, the treated sheets and the sheets that were not subjected to plasma treatment were tested for brown color in the experiment. The physical properties were measured in the same manner as in 1, and the results were as follows.

Experiment No. 3 The same molded sheet as in Experiment No. 2 was used, and this sheet was installed between the internal electrodes (between the high-frequency rod-shaped electrode and the earth plate electrode) in the plasma generator.

Next, after reducing the pressure inside the device to 0.05 torr, trimethylamine gas was introduced, and the gas was heated to 110K under 0.5 torr.
A high frequency power of 800 W of Hz was applied to generate low temperature plasma, and the sheet was treated for 5 minutes. Regarding this treated sheet, experiment No. When the physical properties were measured in the same manner as l,
The results were as follows.

Experiment Brown 4 Experiment No. 3, the power is 1101 (Hz8O
Low-temperature plasma treatment was performed in the same manner except that high-frequency power of 5 KHz 2 KW was used instead of OW.

Experiment with this treatment sheet. The physical properties were measured in the same manner as in 1, and the results were as follows.

Experimental brown 5 Experimental brown. The same molded sheet as in 2 was used, and this sheet was used in the experimental brown color. Low-temperature plasma treatment was performed using the same plasma generator as in 3.

At that time, the inside of the apparatus was replaced with nitrogen gas in advance, and after further reducing the nitrogen residual pressure to 0.2 torr, methylamine gas was introduced, and a high-frequency power of 13.56 MHz 1 KW was applied under 1 torr of the gas to generate low-temperature plasma. , the formed sheet between the internal electrodes was treated for 3 minutes. Experimenting with this treatment sheet? ．． The physical properties were measured in the same manner as in 1, and the results were as follows.

Experiment. 6 Experiment No. Using the same molded sheet as in 2, set this sheet in an external electrode type low temperature plasma generator (the electrode is of the induction type using a coil), and then 10-4.
The pressure was reduced to Torr, then dimethylformamide gas was introduced, and the frequency was reduced to 13.56MHz70 under a gas pressure of 5 x 10-1 Torr.
Generate low-temperature plasma by applying 0W high-frequency power,
One sheet in the device was processed and closed.

The physical properties of this treated sheet were measured in the same manner as in 0.1, and the results were as follows.

Experimental brown 7 Vinyl chloride-vinyl acetate copolymer (SC-400G) 1
0 parts by weight, 2.5 parts by weight of dibutyltin mercaptide,
0.5 parts by weight of dibutyltin malate, 0.5 parts by weight of calcium stearate. A blend consisting of a weight part and 0.1 part by weight of polyethylene wax was roll-kneaded at 175°C for 10 minutes, and then press-molded at 180°C to form a sheet with a thickness of 0.57 m.

Use this sheet as an experiment. Using the same equipment and electrodes as in 1, and installing it between the electrodes, reduce the pressure inside the equipment to a residual pressure of 0.1 torr, then introduce allylamine gas, and reduce the pressure to 1 torr of gas.
A low-temperature plasma was generated by applying high-frequency power of 3.5 degrees ZIKW, and the sheet was treated for 5 minutes.

Regarding the sheets treated with low-temperature plasma in this way and the sheets not treated with low-temperature plasma, Experiment No. l
The physical properties were measured in the same manner as above, and the results are as follows.

Experiment No. 8 Experiment No. The same molded sheet as in 7 was used in Experiment No. Low-temperature plasma treatment was performed using the same equipment as in 7, but the atmospheric leak pressure was 7×10
- Under 1 torr, the total pressure was set to about 1.7 torr while passing 1 torr of allylamine gas partial pressure, and the total pressure was 13.56 MH.
A high frequency power of 1 KW was applied to generate low temperature plasma, and the sheet placed between the electrodes was treated for 5 minutes.

Experiments were carried out on sheets treated in this way. Physical properties were measured in the same manner as in 1.

Experiment No. 9 Experiments. The same molded sheet as in 7 was used as an experimental brown. Low-temperature plasma treatment was performed using the same equipment as in 7, but the inside of the equipment was heated to 1X before treatment.
The pressure was reduced to 10-4 torr, and then the internal pressure was adjusted to 0-2 torr per cut while passing carbon dioxide gas through.

Thereafter, the total pressure was brought to about 2.1 x 10-1 Torr while passing n-butylamine gas at a partial pressure of 2 x 10-1 Torr.
．． High-frequency power of 56 MHz and 700 W was applied to the electrode to generate low-temperature plasma, and the sheet placed inside the electrode was treated for 3 minutes. Experiment No. 1 was obtained for the sheet treated in this way. The physical properties were measured in the same manner as in 1.

Reference Experiment Example Experiment NO. 7
Low-temperature plasma treatment was carried out using the same apparatus as above, but prior to treatment, the pressure inside the apparatus was reduced to 0-4 torr, and then the internal pressure was adjusted to 1 x 10-2 torr while nitrogen gas was vented.

Claims (1)

[Claims] 1. A vinyl chloride resin molded product is heated to a gas partial pressure of 10^-^2
In an atmosphere of a nitrogen atom-containing organic compound (excluding organosilicon compounds) of ~10 torr and an inorganic gas with a gas partial pressure of 10^-^4 to 10 torr, high-frequency power of 10 KHz or higher is applied between the electrodes to reduce the temperature. A method for surface treatment of a vinyl chloride resin molded article, which comprises subjecting the molded article to plasma treatment and providing a polymer film of the nitrogen atom-containing organic compound on the surface of the molded article. 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 has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (wherein R^1, R^5 and R^6 are hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups ) The surface treatment method according to claim 1, wherein the surface treatment method is a compound represented by: 4 The nitrogen atom-containing organic compound has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (in the formula, R^8 is a substituted or unsubstituted divalent hydrocarbon group, R^7, R^9, R^ 1^0
2. The surface treatment method according to claim 1, wherein R^1^1 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group.