JPH05202208A - Method of surface-treating vulcanized rubber - Google Patents

Abstract

PURPOSE:To provide the title method which can easily be carried out in a clean environment, can give a vulcanized rubber having far better surface adhesion than one obtained by low-pressure glow plasma treatment, and does not impair the properties inherent in the rubber because only an extremely thin surface layer is treated. CONSTITUTION:The title method comprises treating the surface of a vulcanized rubber with an atmospheric-pressure plasma obtained from a gas containing oxygen atoms and a gas containing halogen atoms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for surface-treating a vulcanized rubber, particularly for the purpose of joining another material to the vulcanized rubber.

[0002]

BACKGROUND OF THE INVENTION The surface treatment of vulcanized rubber is carried out by joining the vulcanized rubber with another rubber material or another material such as metal or resin to produce a composite material or vulcanization. It is used as a pretreatment for painting rubber,
Conventionally, various surface treatment methods are known.

For example, there is known a method of strongly oxidizing the surface of a vulcanized rubber with a strong acid or a strong oxidant to give adhesiveness to the vulcanized rubber to generate fine cracks on the entire surface. This method requires the handling of a strong acid and a strong oxidant with great care, and also has the problem that the physical properties of the vulcanized rubber are significantly impaired by the strong acid and the strong oxidizer, and it is difficult to give a sufficient adhesive force.

Further, a chlorine treatment method in which a vulcanized rubber is exposed to chlorine gas and a surface treatment method using a pseudohalogen compound (see Japanese Patent Publication No. 52-36910) are also proposed.
All of these methods attack double bonds in rubber,
This is a surface treatment method for forming a Cl group to make the surface easy to adhere. When the surface treatment of the vulcanized rubber is carried out by these methods, for example, it is compounded with another material such as metal or resin to form a vibration-proof rubber ( Since the surface to be treated becomes a resin during the production of (NR / SBR), there is a problem that the adhesiveness and heat resistance become poor. There is also a problem that the surface to be treated turns yellow. For example, using this method, the golf ball body made of vulcanized rubber whose main component is balata (trans polyisoprene) is surface treated and painted. When a golf ball is manufactured, there is a problem that the appearance of the golf ball is impaired. Further, there is a problem that chlorine gas and pseudo halogen compounds cause environmental destruction.

Still another surface treatment method is O ₂ or CF ₄
There is a method in which the surface of the vulcanized rubber is etched and oxidized by a low-pressure glow plasma treatment method using a gas such as a mixed gas of OH and O ₂ . However, in the low-pressure glow plasma treatment, a uniform surface treatment with less unevenness of treatment can be performed. However, since the low-pressure plasma treatment is usually performed at a low pressure of 10 Torr or less, a large vacuum device is required when performing this industrially. , And for continuous processing,
Equipment cost and processing cost increase. Furthermore, in a reduced-pressure atmosphere, oil, water, etc. are released from the surface of the vulcanized rubber, so that the desired performance or function may not be obtained in the plasma treatment.

The present invention has been made in view of the above circumstances.
The surface of the vulcanized rubber can be easily surface-treated, and can give good adhesiveness to the surface of the vulcanized rubber and can be bonded to other materials to obtain a good composite material. It is intended to provide a processing method.

[0007]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the surface of a vulcanized rubber is exposed to atmospheric pressure using a gas containing an oxygen atom and a gas containing a halogen atom. When plasma treated, no solvent is used, so surface treatment can be performed easily in a clean environment. Vulcanization with a much better adhesive surface compared to conventional methods such as low pressure glow plasma treatment. The inventors have found that a rubber can be obtained, and that the physical properties of the vulcanized rubber itself are not impaired because only the surface is treated, and the present invention has been completed.

Therefore, the present invention provides a surface treatment method for vulcanized rubber, which comprises subjecting the surface of the vulcanized rubber to atmospheric pressure plasma treatment using a gas containing oxygen atoms and a gas containing halogen atoms.

The present invention will be described in more detail below. In the surface treatment method for vulcanized rubber of the present invention, the surface of the vulcanized rubber is subjected to atmospheric pressure plasma treatment using a gas containing oxygen atoms and a gas containing halogen atoms. It is a thing.

Here, the vulcanized rubber treated by the atmospheric pressure plasma method is not particularly limited, and NR
(Natural rubber) type, SBR (Styrene-butadiene rubber)
System, IR (isoprene rubber) system, NBR (acrylonitrile / butadiene rubber) system, EPM (ethylene / propylene rubber) system, EPDM (ethylene / propylene / diene rubber) system, BR (butadiene rubber) system, IIR (butyl rubber) system, It can be applied to any vulcanized rubber such as CR (chloroprene rubber). The vulcanized rubber may have any shape such as a plate shape, a sheet shape, a spherical shape, a cylindrical shape, a columnar shape, and a block shape.

Among the reaction gases used in the surface treatment method according to the present invention, the gas containing oxygen atoms is O ₂ , H ₂ O, C.
Gas such as O _2, alcohols, ketones, include such as a gas of an oxygen-containing organic substances such as ethers, of which in particular O ₂ is preferably used.

Further, as the gas containing a halogen atom,
Simple gases such as F ₂ , Cl ₂ , Br ₂ , and I ₂ , HF, HCl,
Hydrogen halides such as HBr and HI, CF ₄ , CClF ₃ ,
Freon such as CCl ₂ F ₂ and C ₂ F ₆ , halon such as CBrF ₃ and CHClF ₂ , CHBrF ₂ , CHCl ₃ and CH ₂ Cl
₂ , halogenated hydrocarbons such as CH ₃ CCl ₃ and CCl ₄ , S
F _{6 and the} like can be mentioned. Of these, fluorocarbons, halons, and halogenated hydrocarbons are preferably used from the viewpoint of easy handling, and the following are particularly preferable in combination with the above-mentioned gas containing oxygen from the viewpoint of easy handling.

O ₂ + CCl ₂ F ₂ , O ₂ + CClF ₃ , O ₂ + CHCl
F ₂ , O ₂ + CBrF ₃ , O ₂ + CF ₄ , O ₂ + CF ₄ + CHC
l ₃ , O ₂ + CF ₄ + CH ₂ Cl ₂ , O ₂ + CF ₄ + CCl ₄ , O ₂ + CF ₄ + CH ₃ CCl ₃

The gas containing oxygen atoms and halogen atoms at the same time can be used alone.

When the surface treatment is carried out using the above-mentioned reaction gas, it is preferable to dilute the above-mentioned reaction gas with a gas which is easy to glow discharge at atmospheric pressure in order to stably obtain atmospheric-pressure plasma. As such a gas, specifically, helium,
An inert gas such as argon or neon, a general-purpose gas such as nitrogen or hydrogen, a gas of various organic substances, or a mixture of two or more gases can be used. Of these, helium is particularly preferably used.

These gases do not necessarily have to be gaseous at room temperature, and the supply method is selected depending on the discharge region temperature and the state (solid, liquid, gas) at room temperature. That is, if it is gaseous at the temperature of the discharge region or at room temperature, it can be allowed to flow into the processing container as it is. The liquid may be bubbled with an inert gas or the like to flow in, or the liquid may be applied to the surface of the vulcanized rubber which is the object to be treated and used.
On the other hand, when it is not in a gaseous state and has a relatively low vapor pressure, it can be used by heating it in a state where the gaseous state or the vapor pressure is high.

As a method of generating atmospheric pressure plasma according to the present invention, any method can be adopted as long as it is a method capable of generating glow discharge at a pressure near atmospheric pressure.
There are roughly two types of voltage application methods, DC and AC, but industrially AC discharge is easier.

When the internal electrode type AC discharge is adopted, it is recommended to cover at least one of the electrodes with an insulator in order to easily obtain stable atmospheric pressure plasma. Also,
When the processing chamber is made of an insulating material such as glass, the external electrode method can be adopted. Further, a coil type discharge or a waveguide type discharge is also possible. In the case of direct current discharge, it is preferable that neither the high voltage application side electrode nor the ground side electrode is covered with an insulator in order to form and stabilize a direct current glow by direct inflow of electrons from the electrode.

Explaining an example of a manufacturing apparatus used for carrying out the surface treatment according to the present invention, for example, an apparatus as shown in FIG. 1 can be cited. That is, this apparatus accommodates the object 2 to be processed in the processing chamber 1 in which the plasma discharge region is formed, and in the processing chamber 1, a gas containing an oxygen atom and a gas containing a halogen atom, and a gas for diluting the gas. The surface treatment is performed by supplying gas from the gas supply pipe 3 and forming plasma discharge regions in the electrodes 4 and 4. The electrodes 4 and 4 are covered with an insulating material and are arranged so as to face each other with a predetermined gap therebetween. One electrode 4 is connected to an AC power source 5 and the other electrode 4 is grounded. An object to be treated 2 (vulcanized rubber) is arranged between the electrodes 4 and 4 to perform surface treatment. In addition, 6 is a gas discharge pipe (exhaust system).

Since the surface of the vulcanized rubber which has been surface-treated according to the present invention has been modified to a surface which is highly easily adhered, the surface of the vulcanized rubber can be changed to another surface by a known method such as heating, pressure bonding or thermocompression bonding. The members can be easily bonded.

In this case, the other member may be an organic solid or an inorganic solid such as plastic, rubber, metal, ceramic, etc., and the shape thereof is plate, sheet, fiber or block. It does not matter what shape it is.

When joining the surface-treated vulcanized rubber and other members, an adhesive is generally used. Examples of the adhesive include silane coupling agents, aminosilane coupling agents, and epoxies. Adhesives such as system-based, urethane-based, phenol-based, acrylic-based, and rubber-based adhesives are used, and can be appropriately selected depending on the types of other members to be bonded to the vulcanized rubber, the surface condition thereof, and the bonding method. Depending on the type of the member and the surface treatment conditions of the vulcanized rubber, it is possible to directly bond without using an adhesive.

The method of the present invention is applied to the production of various vulcanized rubber composite materials, and is particularly preferably applied to the production of golf balls, anti-vibration rubber, recycled tires and the like.

[0024]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 14, Comparative Examples 1 to 12] FIG.
The surface treatment of the vulcanized rubber obtained by vulcanizing the rubber composition having the following composition was performed under the conditions shown in Table 1 using the atmospheric pressure glow discharge device shown in FIG. (Examples 1 to 14). Further, for comparison, an untreated vulcanized rubber (Comparative Example 1), a vulcanized rubber treated with a pseudohalogen compound (Comparative Example 2), and a vulcanized rubber treated with a low pressure glow plasma under the conditions shown in Table 1 (Comparative Examples 3 to 3). The following experiment was conducted for 12). The results are also shown in Table 1.

Experiment 1 A rubber composition consisting of trans polyisoprene 30 parts SBR (manufactured by Japan Synthetic Rubber Co., Ltd., 1502) 50 NR 20 sulfur 1 zinc white 5 Nocrac NS-6 (manufactured by Ouchi Shinko Chemical Co., Ltd.) 1 was used. After vulcanization, 10 × 60 × 3mm
The test piece of was produced. The processing conditions shown in Table 1 (Examples 1 to 1)
9, two surface treatments in Comparative Examples 1 to 7) were applied, urethane-based adhesive was applied to the treated surfaces, the applied surfaces were superposed and adhered, and a T-shaped peeling test was performed as shown in FIG. The adhesive strength was measured. In FIG. 2, 7 is a vulcanized rubber test piece and 8 is a urethane adhesive.

Experiment 2 The surface of a vulcanized rubber test piece similar to that in Experiment 1 was surface-treated under the treatment conditions (Examples 2 to 9) shown in Table 1, and a urethane-based adhesive was applied to the treated surface to form a polyester-based nonwoven fabric. And a 180 ° peel test was performed as shown in FIG. 3 to measure the adhesive force. In addition, in FIG. 3, 9 is a nonwoven fabric.

Experiment 3 SBR (manufactured by Japan Synthetic Rubber Co., Ltd., 1502) 50 parts NR 50 carbon black 60 sulfur 2 zinc white 5 antioxidant (Note 1) 1 vulcanization accelerator (Note 2) 1 (Note 1) N, N′-diphenyl-p-phenylenediamine (DPPD) (Note 2) 34 × 75 × 5 mm after vulcanizing a rubber composition consisting of N-oxydiethylene-2-benzothiazole (NOBS)
The test piece of was produced. The processing conditions shown in Table 1 (Example 3 to
9 and Comparative Examples 1, 2 and 4 to 7) were each subjected to surface treatment, and the treated surface was coated with a phenol-based adhesive, and then the coated surfaces were superposed on each other and heat-pressed at 150 ° C. for 30 minutes for adhesion. It was Similar to Experiment 1, the T-shaped peeling test shown in FIG. 2 was performed to measure the adhesive force.

Experiment 4 NBR (N2305 manufactured by Japan Synthetic Rubber Co., Ltd.) 100 parts Carbon black 60 Sulfur 2 Zinc white 5 Anti-aging agent (Note 3) 1 Vulcanization accelerator (Note 4) 1 Mineral oil 2 (Note 3) N -Phenyl-N'-isopropyl-p-phenylenediamine (NOCRAC 810-NA) (Note 4) Tetramethylthiuram monosulfide (TM)
A rubber composition consisting of TM) was vulcanized at 150 ° C. for 20 minutes, and then a test piece of 34 × 75 × 5 mm was prepared. Surface treatment was performed under the treatment conditions shown in Table 1 (Examples 8 to 12 and Comparative Examples 10 to 14), a phenol adhesive was applied to the treated surface, and 1
After heat treatment in an oven at 50 ° C. for 30 minutes, glass fiber-filled nylon (filling ratio 50%) was injection-molded on the above-mentioned phenol resin adhesive using a resin injection machine. The same 180 ° peel test as shown in FIG. 3 was performed to measure the rubber breakage (area%).

[0030]

[Table 1]

As can be seen from Table 1, in the case of low pressure glow plasma treatment (Comparative Examples 8 to 12), the treatment time was 0.5 to
Rubber damage increases up to 2 minutes, but if the treatment time is longer than 2 minutes, the rubber fracture decreases and the adhesiveness deteriorates. Furthermore, even the 2 minute treatment, which shows the maximum value of rubber fracture, causes 100% area damage of rubber. It does not reach. On the other hand, in the case of the atmospheric pressure plasma treatment (Examples 10 to 14), the rubber breakage was 100% by area in 0.5 minute treatment, and the adhesiveness did not change even if the treatment time was lengthened. In the case of low-pressure glow plasma treatment, when rubber is exposed to a plasma atmosphere under reduced pressure for a long time, the temperature of the rubber rises and gas in the rubber is generated. It is considered that the plasma treatment does not generate gas from the rubber because the rubber is not put under a reduced pressure, and a stable surface treatment can be performed.

[0032]

According to the present invention, the vulcanized rubber can be surface-treated easily in a clean environment, and has a much better adhesive surface than the case of low-pressure glow plasma treatment. Rubber can be obtained, and the physical properties of the vulcanized rubber itself are not impaired because only the surface is treated.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an atmospheric pressure plasma discharge device used in an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a T-shaped peel test in Examples and Comparative Examples of the present invention.

FIG. 3 is an explanatory diagram of a 180 ° peel test in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 1 Processing Room 2 Processing Object 3 Gas Supply Pipe 4 Electrode 5 AC Power Supply 6 Gas Discharge Pipe 7 Vulcanized Rubber Test Piece 8 Urethane Adhesive 9 Nonwoven Fabric

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Setsuo Akiyama 2-5 of 28, Miyashitahonmachi, Sagamihara-shi, Kanagawa (72) Inventor Masato Yoshikawa 3-5-9-202, Ogawahigashi-cho, Kodaira-shi, Tokyo (72) Inventor Toshio Naito 969-1 Makinagi, Miyamae-ku, Kawasaki-shi, Kanagawa (72) Inventor Sachiko Okazaki 2-20-11, Takaido Higashi, Suginami-ku, Tokyo (72) Masuhiro Ogoma 843-15 Shimoshinkura, Wako-shi, Saitama

Claims (1)

[Claims] 1. A method for treating the surface of a vulcanized rubber, which comprises subjecting the surface of the vulcanized rubber to atmospheric pressure plasma treatment using a gas containing an oxygen atom and a gas containing a halogen atom.