JPS6157332B2 - - 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, provides durable and permanent antistatic properties to the molded articles by subjecting the surface of the vinyl chloride resin molded article to low-temperature plasma treatment. The purpose is to In general, vinyl chloride resin molded products are extremely susceptible to being charged with electricity, resulting in dirt on the exterior due to the adhesion of dust, dirt, etc., and problems such as the effects of accumulated static electricity on the human body (electric shock) and spark discharge. It has points. 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. and processability deteriorates,
This has the disadvantage that the surface of the molded product becomes colored and easily becomes dirty. On the other hand, attempts have been made to treat the surface of vinyl chloride resin molded products with low-temperature plasma of inorganic gases such as helium, argon, nitrogen, oxygen, and carbon monoxide to make them hydrophilic, thereby suppressing charging. efforts have been made, but sufficient effects cannot be obtained. The present inventors have completed the present invention as a result of extensive research in order to solve these problems.
This relates to a surface treatment method for a vinyl chloride resin molded article, which comprises subjecting the surface of the vinyl chloride resin molded article to low-temperature plasma treatment with a nitrogen atom-containing organic compound and low-temperature plasma treatment with an organosilicon compound. It is something. According to the method of the present invention, the surface properties of the molded article are modified without impairing its inherent mechanical strength, and the low-temperature plasma treatment of the nitrogen atom-containing organic compound and the low-temperature plasma treatment of the organosilicon compound are performed. It was confirmed that the synergistic effect of the treatments provided antistatic properties that were even more permanent and durable. By performing both of these treatments, an extremely thin modified layer is formed on the surface of the molded product, and this layer has the characteristic of strongly bonding to vinyl chloride resin.
Furthermore, the formation speed of this modified layer is faster than when the molded article is made of other polymers, and it is thought that this is because the effects of the low-temperature plasma treatment on both of them are noticeable. The method of the present invention will be explained in detail below. In carrying out the method of the present invention, the nitrogen atom-containing organic compound used to form the low-temperature plasma of the nitrogen atom-containing organic compound is:
Especially general formulas or A compound represented by is desirable. In the above general formula, R ¹ and R ⁴ are substituted or unsubstituted monovalent hydrocarbon groups, R ² , R ³ , R ⁶ , R ⁷ and R ⁸ are hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups, R ⁵ represents a substituted or unsubstituted divalent hydrocarbon group, respectively. Specifically, such nitrogen atom-containing organic compounds include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n-
propylamine, tri-n-propylamine, n
-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, Examples include amines such as ethyleneimine, 1-methylethyleneimine, N·N-dimethylformamide, formamide, capronamide, aminoacetal, benzylamine, piperidine, pyrrolidine, and morpholine, imines, amides, imides, and derivatives thereof. Note that two or more of these may be used in combination. On the other hand, the organosilicon compounds used to form the low-temperature plasma of organosilicon compounds are especially organosilane compounds represented by the general formula R _a H _b SiX _4-ab and their hydrolyzed condensates. is desirable. In this general formula, R is a methyl group, an ethyl group, a propyl group,
Monovalent hydrocarbon groups such as alkyl groups such as butyl groups, alkenyl groups such as vinyl groups and allyl groups, alkynyl groups such as ethynyl groups, propynyl groups and butynyl groups, aryl groups such as phenyl groups and naphthyl groups, and monovalent hydrocarbon groups such as these groups. Indicates a substituted monovalent hydrocarbon group in which the hydrogen atoms of the valent hydrocarbon group are partially substituted with other atoms (such as halogen) or groups (such as cyano group), and X in the formula represents a halogen such as chlorine or bromine, methoxy group,
Indicates an alkoxy group such as an ethoxy group or a butoxy group. In addition, a in the formula is 0, 1, 2, 3, or 4, b is 0, 1, or 2, but a+b is 0,
1, 2, 3 or 4. Specific examples of such organosilicon compounds include trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, vinyldimethylchlorosilane, vinyldimethylmethoxysilane, vinyldimethylethoxysilane, ethynyldimethylmethoxysilane, ethynyldimethylchlorosilane, and methylchlorosilane. Methylmethoxychlorosilane, triethylmethoxysilane, dimethylchloromethylethoxysilane, dimethylchloromethylchlorosilane, dimethylphenylmethoxysilane, 2-chloroethynyldimethylchlorosilane,
2-chloroethyldimethylmethoxysilane, methyldichlorosilane, dimethyldimethoxysilane,
Diethyldimethoxysilane, dimethyldiethoxysilane, vinylmethyldichlorosilane, vinylmethyldimethoxysilane, 2-chloroethylmethyldimethoxysilane, vinylmethyldiethoxysilane, chloromethylmethyldichlorosilane, dimethoxymethylphenylsilane, chloromethylmethyldimethoxysilane , methyltrimethoxysilane,
Examples include methyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, chloromethyltrimethoxysilane, 2-chloroethyltrimethoxysilane, tetramethoxysilane, and tetraethoxysilane. In the formula, X corresponds to an alkoxy group or chlorine, but the same applies when it is another halogen element such as bromine), as well as the formula R ₄ Si, which is clearly included in the above general formula,
_R3SiH , (R)(H)Si(X) ₂ , _HSiX3 , (R) ₂
(H) Those corresponding to Si(X) can also be mentioned. Note that two or more of these may be used in combination. All of the organosilicon compounds exemplified above correspond to organosilane compounds, but in the present invention, hydrolyzed condensates of these compounds can also be used, including divinyltetramethyldisiloxane, dichlorosiloxane, Examples include methyltetramethyldisiloxane, diethynyltetramethyldisiloxane, and tetramethyldisiloxane. Of course, other hydrolysis condensates can also be used, but high condensates that are difficult to gasify are unsuitable. 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. An example is olefin. 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 phthalic acid esters such as dioctyl phthalate, dibutyl phthalate, and butylbenzyl phthalate, and aliphatic esters such as dioctyl adipate and dibutyl sebacate. Basic acid esters, pentaerythritol esters, glycol esters such as diethylene glycol dibenzoate, fatty acid esters such as methyl acetyl ricinoleate, phosphate esters such as tricresyl phosphate, triphenyl phosphate, epoxidized soybean oil, epoxidized linseed Epoxidized oils such as oils, citric acid esters such as acetyl tributyl citrate and acetyl trioctyl citrate, trialkyl trimellitate, tetra-n-octyl pyromellitate, polypropylene adipate, and other polyesters with various structures. An example is a plasticizer. In addition, calcium stearate,
Metal salts of carboxylic acids such as zinc stearate, lead stearate, barium stearate, cadmium stearate, tribasic lead sulfate, dibasic lead phosphite, dibutyltin dilaurate, di-n-octyltin malate, Examples include organic tin compounds such as -n-octyltin mercaptite, esters such as butyl stearate, fatty acid amides such as ethylene bisstearamide, higher fatty acids and their esters, and polyethylene wax. 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-styrene. -Butadiene copolymer, acrylonitrile-styrene-
Examples include butadiene copolymers, urethane elastomers, polyamide resins, ethylene-propylene-diene terpolymers, and epoxy-modified polybutadiene resins. Please note that these are vinyl chloride resins.
It is desirable to use the compound in an amount of 50 parts by weight or less per 100 parts by weight. 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. The present invention modifies the surface characteristics of such molded products by subjecting the surface of such vinyl chloride resin molded products to both of the above-mentioned low-temperature plasma treatments, resulting in highly durable and long-lasting antistatic properties. The specific method of this treatment is basically to charge a vinyl chloride resin molded product into a low-temperature plasma generator, and to add the above-mentioned nitrogen atom-containing organic compound or 10 minutes inside the device while flowing gas of one of the organosilicon compounds.
Adjust and maintain the pressure to below 10 Torr, generate low temperature plasma under this gas pressure, expose the molded product to the low temperature plasma of the gas, and then reduce the pressure within the device to below 10 Torr while passing the gas from the other gas. The plasma treatment is performed in two steps: adjusting and holding the gas, generating low-temperature plasma under the gas pressure, and exposing the molded article to the low-temperature plasma of the gas. In this two-step plasma treatment, either the low-temperature plasma treatment step for the nitrogen atom-containing organic compound or the low-temperature plasma treatment step for the organosilicon compound may be performed first, but the effect of the present invention can be more pronounced. In order to achieve this, it is desirable to first perform low-temperature plasma treatment on the nitrogen atom-containing organic compound, and then perform low-temperature plasma treatment on the organosilicon compound. After the low-temperature plasma treatment of the nitrogen atom-containing organic compound, the system may be evacuated once to create a vacuum state, and then the organosilicon compound may be introduced and the next low-temperature plasma treatment may be performed. During low-temperature plasma treatment of organic compounds, the amount of organic silicon compound gas is gradually increased and mixed over time, and at the same time the amount of nitrogen-containing organic compound gas is gradually decreased, and finally the organic silicon compound alone is treated at low temperature. A method of transferring to plasma treatment may also be used. Furthermore, there is a method of introducing other types of inert gas or reactive gas into the system after the completion of the first-stage low-temperature plasma treatment and exposing the molded product surface to these gases to perform the second-stage low-temperature plasma treatment, or to increase the treatment effect. Therefore, it is also effective to subject the molded product to heat treatment, ultraviolet light treatment, and low-temperature plasma treatment with inorganic gas. In carrying out the above two-step plasma treatment, an inert gas such as helium or argon is used together with the nitrogen atom-containing organic compound and organosilicon compound gas.
Nitrogen, oxygen, air, hydrogen, water vapor, carbon dioxide,
An inorganic gas such as carbon monoxide, a nitrogen atom-containing organic compound, and an organic gas other than an organosilicon compound may be coexisting. In addition, when an inorganic gas is coexisting, the gas partial pressure is that of a nitrogen atom-containing organic compound or an organosilicon compound.
10 ^-3 to 10 torr, preferably 10 ^-4 to 10 torr for inorganic gas. This not only provides excellent antistatic properties (reduced surface resistance) with excellent durability and sustainability, but also has the advantage of providing wettability, printability, adhesion, etc. . In the above processing method, if the pressure of the low-temperature plasma gas in the device is 10 Torr or more, it will be difficult to obtain a processed molded product with excellent antistatic properties, so the gas pressure of this low-temperature plasma should be 10 Torr or less. It is preferably in the range of 1 to 0.005 Torr. Low-temperature plasma treatment at this gas pressure imparts excellent antistatic properties, but when the gas pressure exceeds 10 Torr, the antistatic properties rapidly decrease (accompanied by an increase in surface resistance). Such a phenomenon is completely unexpected from the knowledge obtained in conventional plasma polymerization and plasma treatment. As conditions for generating low-temperature plasma, for example, a power of 10 KHz to 100 MHz and 10 W to 100 KW may be applied to the electrodes, and either an internal electrode method or an external electrode (electrodeless) method may be used. Further, a sufficient reforming effect can be obtained regardless of the type of discharge (glow discharge, corona discharge, etc.). The plasma processing time varies depending on the applied power and the like, but generally several seconds to several tens of minutes is sufficient. Next, a specific example will be given. Example 1 A blend consisting of 100 parts by weight of vinyl chloride resin, 3 parts by weight of barium-zinc stabilizer, 50 parts by weight of DOP, and 2 parts by weight of epoxidized soybean oil was roll-kneaded at 170°C for 10 minutes, and then kneaded at 175°C. Press molded and thickness
A 0.5 mm sheet was created (untreated sheet). Set this sheet in the plasma generator,
After reducing the pressure inside the apparatus to 10 ^-4 Torr, the pressure inside the apparatus was adjusted and maintained at 0.3 Torr while introducing ethylamine gas, and high-frequency power of 13.56MHz 1KW was applied to generate low-temperature plasma and the sheet was processed for 1 minute (processed sheet 1). On the other hand, the sheet was subjected to low-temperature plasma treatment for 3 minutes in the same manner as above except that trimethylchlorosilane was used instead of ethylamine gas (treated sheet 2). In addition, low-temperature plasma treatment was performed in exactly the same manner as for treatment sheet 1, and then the pressure inside the apparatus was reduced to 10 ^-4 Torr, and then adjusted and maintained at 0.4 Torr while introducing trimethylchlorosilane gas, and high frequency power of 13.56MHz 500W was applied. A low-temperature plasma was generated and the sheet was treated for 3 minutes (treated sheet 3). When the tobacco ash adsorption distance, surface resistivity, and frictional charging voltage were measured for the thus treated sheets 1, 2, and 3 and the untreated sheet, the results shown in Table 1 were obtained.

[Table] Example 2 A blend consisting of 100 parts by weight of vinyl chloride resin, 3 parts by weight of dibutyltin mercaptide stabilizer, and 0.1 part by weight of polyethylene wax lubricant was roll-kneaded at 180°C for 10 minutes, and then pressed at 185°C. mold,
A sheet with a thickness of 1 mm was prepared (untreated sheet). Set this sheet inside the plasma generator,
After reducing the pressure inside the apparatus to 10 ^-4 torr, the inside of the apparatus was adjusted and maintained at 0.08 torr while introducing dimethylamine gas, and high-frequency power of 13.56 MHz and 700 W was applied to generate low-temperature plasma and the sheet was treated for 2 minutes. Next, the pressure inside the apparatus was reduced to 10 ^-4 torr, and then adjusted and maintained at 0.1 torr while introducing vinylmethyldimethoxysilane gas, and high-frequency power of 13.56 MHz and 1 KW was applied to generate low-temperature plasma, and the sheet was treated for 1 minute. When various physical properties were measured in the same manner as in the previous example for sheets treated in this manner and sheets that were not subjected to any low-temperature plasma treatment, the results shown in Table 2 were obtained.

[Table] Example 3 A blend consisting of 100 parts by weight of vinyl chloride resin, 1.5 parts by weight of dibutyltin maleate, 1 part by weight of calcium stearate, 0.5 parts by weight of zinc stearate, and 1 part by weight of stearic acid was rolled at 180°C for 10 minutes. Knead and press-form at 185℃ to a thickness of 1.
mm sheet was created (unprocessed sheet). Set this sheet inside the plasma generator,
After reducing the pressure inside the device to 10 ^-4 torr, adjust and maintain the inside of the device at 0.05 torr while introducing argon gas.
Next, methylamine gas was introduced into this, and the partial pressure of methylamine gas was 0.1 torr, and the partial pressure of argon gas was 0.05.
I adjusted it to the torque. In this state, high-frequency power of 13.56 MHz and 200 W was applied to generate low-temperature plasma, and the sheet was treated for 5 minutes (treated sheet 1). On the other hand, the sheet was subjected to low-temperature plasma treatment for 3 minutes in the same manner as above except that trimethylmethoxysilane was used instead of methylamine gas (treated sheet 2). Further, the sheet was subjected to low-temperature plasma treatment in exactly the same manner as Treated Sheet 1, and then the pressure inside the apparatus was reduced to 10 ^-4 Torr, and then the pressure inside the apparatus was adjusted and maintained at 0.05 Torr while introducing atmospheric air. Next, trimethylmethoxysilane gas was introduced into this, and the partial pressure of the mrimethylmethoxysilane gas was adjusted to 0.3 torr and the atmospheric partial pressure to 0.05 torr. In this state, high frequency power of 13.56 MHz and 400 W was applied to generate low temperature plasma, and the sheet was treated for 3 minutes (treated sheet 3). Regarding sheets 1, 2, and 3 treated in this way, and sheets that were not treated,
When the tobacco ash adsorption distance, surface resistivity and frictional charging voltage were measured, the results shown in Table 3 were obtained.

[Table] Example 4 A vinyl chloride resin sheet obtained by molding in the same manner as in Example 2 was set in a plasma generator, and the inside of the device was opened.
After reducing the pressure to 10 ^-4 torr, the inside of the device was adjusted to 0.05 torr while introducing allylamine gas, and then maintained at 0.05 torr.
High-frequency power of 110KHz3KW was applied to generate low-temperature plasma and the sheet was treated for 30 seconds. This treated sheet was taken out into the atmosphere and kept at 50°C for 24 hours, then placed back into the plasma generator and the pressure inside the equipment was reduced to 10 ^-4 torr, and then nitrogen gas was introduced while adjusting and maintaining the inside of the equipment at 0.1 torr. Tetramethoxysilane gas was introduced into this, the partial pressure of tetramethoxysilane gas was adjusted to 0.1 torr, and the partial pressure of nitrogen gas was adjusted and maintained at 0.1 torr, and then high-frequency power of 110 KHz2KW was applied to generate low-temperature plasma and the sheet was treated for 30 seconds. When the various physical properties of the sheet subjected to the two-stage low temperature plasma treatment were measured in the same manner as in Example 1, the results were as shown in Table 4.

[Table] Example 5 100 parts by weight of vinyl chloride-vinyl acetate copolymer (vinyl acetate content: 16% by weight), 1 part by weight of epoxidized soybean oil, 1 part by weight of dibutyltin mercaptide, 0.5 parts by weight of calcium stearate, carbon A blend consisting of 0.1 part by weight of black was kneaded at 180°C for 10 minutes and press-molded at 185°C to obtain a plate-like body with a thickness of 5 mm. After setting this plate-shaped body in a plasma generator and reducing the pressure inside the device to 10 ^-4 Torr, the inside of the device was adjusted and maintained at 0.05 Torr while introducing ethylenediamine gas, and high frequency power of 110 KHz 3 KW was applied to lower the temperature. Plasma was generated and the plate was treated for 5 minutes. Next, following this treatment, while reducing the amount of ethylenediamine gas introduced, vinyldimethylchlorosilane gas was simultaneously introduced and gradually increased.
During this time, the inside of the apparatus was maintained at 0.05 torr, and after 3 minutes, the inside of the apparatus was switched to low-temperature plasma of vinyl dimethylchlorosilane gas at 0.05 torr, and the plate-shaped body was treated with the low-temperature plasma for an additional 5 minutes. Various physical properties were measured in the same manner as in Example 1 for the plate-like bodies treated in this way and the plate-like bodies that were not subjected to any treatment, and the results were as shown in Table 5.

【table】

Claims (1)

[Scope of Claims] 1. A vinyl chloride resin molded article, characterized in that the surface of the vinyl chloride resin molded article is subjected to low-temperature plasma treatment with a nitrogen atom-containing organic compound and low-temperature plasma treatment with an organosilicon compound. surface treatment method. 2 The nitrogen atom-containing organic compound has the general formula (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, R ² and R ³ are hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups) Surface treatment method described in section. 3 The nitrogen atom-containing organic compound has the general formula (In the formula, R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group, R ⁵ is a substituted or unsubstituted divalent hydrocarbon group, and R ⁶ , R ⁷ and R ⁸ are hydrogen atoms or substituted or unsubstituted monovalent hydrocarbon groups. 2. The surface treatment method according to claim 1, wherein the surface treatment method is a compound represented by a valent hydrocarbon group. 4 The organosilicon compound has the general formula R _a H _b SiX _4-ab (wherein R is a substituted or unsubstituted monovalent hydrocarbon group, X is a halogen atom or an alkoxy group, and a is 0, 1 , 2, 3 or 4, b is 0, 1 or 2, but a+b is 0, 1, 2, 3 or 4
2. The surface treatment method according to claim 1, which is an organosilane represented by the following formula or a hydrolyzed condensate thereof. 5. The low-temperature plasma treatment of the nitrogen atom-containing organic compound is carried out in the presence of the nitrogen atom-containing organic compound with a gas partial pressure of 10 ^-3 to 10 Torr and an inorganic gas with a gas partial pressure of 10 ^-4 to 10 Torr. A surface treatment method according to claim 1, characterized in that: 6. The low temperature plasma treatment of the organosilicon compound is carried out in the presence of the organosilicon compound with a gas partial pressure of 10 ^-3 to 10 Torr and an inorganic gas with a gas partial pressure of 10 ^-4 to 10 Torr. A surface treatment method according to claim 1.