JP2000129015A - Surface modification method of fluorine resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve abrasion resistance of resin surfaces and to obtain high adhesion stably by sputter etching of surfaces of fluorine resin molded articles and subsequently subjecting the surfaces to electric-discharge treatment in an atmosphere containing an unsaturated hydrocarbon. SOLUTION: An alternating power of 0.1-20 Watt/cm2 is applied to a surface of a fluorine resin molded article such as films and sheets under a pressure of 0.0005-0.5 Torr to subject the surface to sputter etching with accelerated ions such as nitrogen. Subsequently, the fluorine resin molded article surface is subjected to plasma electro-discharge treatment by applying a high voltage in an inert gas atmosphere containing 0.01-10 vol.% of a 2-4C alkylene such as acetylene as an unsaturated hydrocarbon to obtain a surface-modified molded article. As an adhesive for this molded article, a halogen polymer-based adhesive, a silane-coupling agent or a phenol-based adhesive is used when the thing the molded article adhere to is a rubber such as NR and NBR, a silicon-based or fluorine-based rubber or a urethane-based rubber, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface modification method for modifying the surface of a fluororesin molded article by sputter etching and discharge treatment.

[0002]

2. Description of the Related Art Fluororesins have excellent properties that are not found in other resins, such as antifouling properties, heat resistance, chemical resistance, transparency, ultraviolet light degradation resistance, weather resistance, and water and oil repellency. . On the other hand, fluororesins are difficult to combine with other materials due to their characteristic poor adhesion. In addition, in order to apply another material to the fluororesin, it is necessary to carry out through an adhesive, but the adhesion with the adhesive is poor, and therefore, the adhesive surface on the fluororesin side is modified, and Attempts have been made to increase the adhesiveness of the material.

[0003] As a method for modifying the surface of a fluororesin molding, a flame treatment described in JP-B-63-10176 can be used.
2. Description of the Related Art Chemical treatment typified by metal sodium treatment and discharge treatment by excimer laser, plasma, or the like are known.
However, the treatment with metallic sodium has a danger of ignition, a problem with the environment due to the use of a large amount of solvent, and a problem with characteristics that the modified portion is vulnerable to ultraviolet rays and heat. Also,
A method using a liquid also in the discharge treatment (JP-A-6-24)
0026, JP-A-6-228343, etc.) have the disadvantage that the processing area is small and the running cost is high.

[0004] For this reason, various methods for performing various discharge treatments using a mixed gas have been proposed. Regarding the atmospheric pressure plasma treatment, for example, Japanese Patent Application Laid-Open No. 5-92530 discloses that in an inert gas atmosphere containing an organic compound having a functional group having the same or an affinity as a functional group of an adhesive as a partner material, A method for performing a discharge treatment on a fluorine film is disclosed. However, according to this method, the dispersibility is poor when the liquid organic compound is supplied to the discharge space in the form of gas and fine particles at normal temperature and normal pressure, and the organic compound is fragmented in the discharge space and maintains the state of the starting material. Therefore, there is a problem that it is difficult to form a desired functional group on the surface of the fluorine film.

Japanese Patent Application Laid-Open No. Hei 6-107828 discloses a method of modifying a surface by atmospheric pressure plasma in which noble gas is used in an amount of 70 mol% or more, CO ₂ and C _n H _{2n + 2} (n = 1 to 4). A method using a hydrocarbon is disclosed,
The gas system is complicated and difficult to control, and the hydrocarbon as an additive gas is a saturated hydrocarbon having low reactivity, so that there is a problem that the processing speed cannot be increased so much to maintain good adhesive strength.

Further, in Japanese Patent Application Laid-Open Nos. Hei 1-306569 and Hei 2-15171, glow discharge is performed at atmospheric pressure, and surface modification of various polymers is attempted using the glow discharge. It was hard to say that sufficient properties could be obtained by the surface treatment.

[0007]

On the other hand, JP-A-51-1
Japanese Patent No. 25455 discloses a surface treatment method for subjecting a fluorinated olefin polymer molded article to a sputter etching treatment under an atmosphere pressure of 0.0005 to 0.5 torr. It is known to be obtained. However, the present inventors examined the adhesiveness under various conditions, the surface of the resin subjected to this treatment has a problem in terms of abrasion resistance,
It has been found that this needs to be improved in practical use. That is, although the problem is unlikely to occur when the adhesive or the like is applied as it is after the production of the film or the like, the surface modification is performed only by friction of the surface, for example, by wiping off the dust adhered (electrostatically adsorbed) with the cloth after the production. It was found that the effect was reduced.

On the other hand, combinations of the above surface treatments have also been attempted. For example, JP-A-6-220228 discloses a method in which a fluororesin surface is subjected to low-temperature plasma treatment and then irradiated with an excimer laser. . But,
This has the problem of high cost.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to improve the abrasion resistance of a resin surface subjected to a sputter etching treatment and to prevent various adhesives and rubbers from being used. Another object of the present invention is to provide a surface modification method which can stably obtain high adhesiveness and is advantageous in cost.

[0010]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies on post-processing of a sputter etching process. As a result, after the sputter etching process, unsaturated hydrocarbons, particularly those having 2 to 2 carbon atoms, were obtained. The present inventors have found that by performing a discharge treatment in an atmosphere containing at least one selected from the alkynes of No. 4, the wear resistance of the resin surface subjected to the sputter etching treatment can be improved, and the present invention has been completed.

That is, the surface modification method of the present invention is characterized in that after the surface of a fluororesin molded product is subjected to sputter etching treatment, a discharge treatment is performed in an atmosphere containing unsaturated hydrocarbons.

As the unsaturated hydrocarbon, various ones can be mentioned as described below.
It is preferably at least one selected from alkynes having 2 to 4 carbon atoms.

As the atmosphere, there are various ones as described later, and it is preferable that the atmosphere contains acetylene in an inert gas. Also,
As the type of the discharge treatment, there are various forms including a treatment performed under a low pressure as described later. The discharge treatment generates a plasma under a pressure of 500 to 1000 torr (hereinafter, referred to as “large”). Pressure plasma treatment ").

The concentration of the acetylene is appropriately set according to the pressure of the discharge atmosphere and the form of the discharge. In the case of the atmospheric pressure plasma treatment, the concentration of the acetylene is
It is preferably 0.01 to 10% by volume.

The shape of the fluororesin molding is not particularly limited as described later, and may be any shape. However, the fluororesin molding is preferably a film or a sheet.

As the above-mentioned fluororesin molded product, there are various types as described later, and among them, a polytetrafluoroethylene (PTFE) film or sheet is preferable.

According to the surface modification method of the present invention, the abrasion resistance of the resin surface subjected to the sputter etching treatment can be improved, High adhesion to rubber and rubber. Although the details of the reason are not clear, it is considered as follows. In other words, the sputter etching process produces fine needle-like projections on the resin surface to improve the adhesiveness. However, these projections have low strength against friction and cause a decrease in the adhesive strength due to friction. It is considered that by performing the discharge treatment in an atmosphere containing a saturated hydrocarbon, the strength of the protrusion against friction was increased, and the wear resistance was improved. Also,
In addition to such improvement in abrasion resistance, a unique surface modification effect by discharge treatment can be obtained. That is, sputter etching is mainly a physical treatment, whereas discharge treatment also involves chemical changes such as carbonization and hydrophilization of the surface, and it is thought that a high adhesiveness can be realized by a synergistic effect of these. Can be

When the unsaturated hydrocarbon is at least one selected from alkynes having 2 to 4 carbon atoms, it has a triple bond between carbon atoms, so that it reacts with other gas molecules or fluororesin in the discharge treatment section. It is considered that the reaction which is high in property and hard to cause a reaction disadvantageous to the surface modification can promote a reaction effective for the surface modification as a whole.

The atmosphere is one containing acetylene in an inert gas, and the discharge treatment is performed in a range of 500 to 1
In the case where plasma is generated under a pressure of 2,000 torr, so-called atmospheric pressure plasma processing causes economical problems such as an increase in equipment costs and processing costs associated with low-temperature plasma, and functional problems such as heat generation in processing. There are few problems, and it is particularly excellent as a post-process of surface modification. Further, among the above-mentioned alkynes, acetylene having particularly good reactivity is used, so that the above-mentioned effects are particularly remarkable.

At this time, the concentration of the acetylene is 0.0
When the content is 1 to 10% by volume, the amount of the formed functional group is sufficient, the adhesion to the adhesive becomes good, and the adhesion is prevented from lowering due to the accumulation of powdery decomposition products. Can be.

When the fluororesin molding is a film or a sheet, the film or the sheet is liable to be subjected to friction in a winding step and other operations.
In particular, when applying an adhesive, it is necessary to wipe off dust and the like adhered by static electricity, so that abrasion resistance is an important performance, and the present invention is particularly useful. In addition, since a continuous process can be adopted when the material is a film or a sheet, the process can be performed quickly, and the subsequent discharge process can be performed without an intermediate winding process that easily causes abrasion. become.

When the above-mentioned fluororesin is polytetrafluoroethylene (PTFE), the combined use of the sputter etching treatment and the discharge treatment becomes remarkable as compared with other fluororesins, and the present invention is particularly effective. Become something. In other words, in the case of other fluororesins, an effect of improving the adhesiveness to some extent can be expected only by the discharge treatment, whereas in the case of polytetrafluoroethylene (PTFE), as shown in the comparative example, only the discharge treatment has a sufficient adhesiveness. However, by performing the combined treatment as in the present invention, sufficient adhesiveness can be realized.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in the order of a fluororesin molded product, a sputter etching process, and a discharge process.

(Fluororesin Molded Article) The form of the fluororesin molded article to be treated includes various forms such as a film, a sheet, a plate, a tube, and a bulk. A film or a sheet-like material is preferable because it can be disposed between the electrodes for efficient processing. The film or sheet may be a porous body or a laminate.

The fluororesin is not particularly limited as long as it contains a fluorine atom in the molecule. Specifically, polytetrafluoroethylene (PTF
E) and its modified products, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE),
Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-vinylidene fluoride copolymer (TFE / VdF), tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymer (EPA), poly Chlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), chlorotrifluoroethylene-vinylidene fluoride copolymer (CTFE / VdF), polyvinylidene fluoride (PVd)
F), polyvinyl fluoride (PVF) and the like.
Among them, as described above, polytetrafluoroethylene (P
TFE) is preferred.

(Sputter etching process) As a source of accelerated ions for performing the sputter etching process, either low-temperature plasma or an ion beam can be used. Examples of the accelerated ions include argon, nitrogen, and oxygen.

As the processing apparatus and processing conditions when using low-temperature plasma, those described in detail in JP-A-51-125455 can be employed. That is, as processing conditions, 0.0005 to 0.5 torr
Is preferable, and an AC voltage is applied between the cathode and the anode. In this case, the fluororesin film to be processed is preferably brought into contact with the cathode. The gas as the accelerating ions may or may not be introduced.

The power supply has a high frequency (several hundred kHz to several tens MH)
z) can be used, but practically 13.56 MHz
It is preferable to use If the pressure is less than 0.0005 torr or more than 0.5 torr, the discharge becomes unstable, which is not preferable. PTFE at 0.01 torr or more
There is a tendency that projections formed on the surface are small and adhesive characteristics are hard to appear. AC power is 0.1-20 Watt / cm ²
If it is less than 0.1 Watt / cm ² , the projections are small and adhesion characteristics are hard to appear, and if it exceeds ²⁰ Watt / cm ² , the amount of generated gas increases, the etching rate reaches a plateau, and power tends to be wasted.

[0029] The processing conditions of the ion beam, pressure 10 ^-7 to
10 ^-5 torr, irradiation amount 10 ¹³ to 10 ¹⁷ ions / cm
² , a voltage of 5 to 50 kv and a current of 10 to 100 mA are preferred. When the irradiation amount is less than 10 ¹³ ions / cm ² , the voltage is less than 5 kv, and the current is less than 10 mA, the protrusion tends to be small. If the irradiation amount exceeds 10 ¹⁷ ions / cm ² , the voltage exceeds 50 kv, and the current exceeds 100 mA, the materials tend to be easily damaged.

FIG. 1 is a schematic diagram of an example of an apparatus used for a sputter etching process. The apparatus transports the fluororesin film 1, a high-voltage applying means for forming a low-temperature plasma, a decompression vessel 22 for maintaining a gas concentration and a pressure, a supply and exhaust means for introducing and exhausting gas. It is composed of four elements of a transport mechanism for feeding out and winding up.

The high voltage applying means includes a cathode 24 and an anode 29
And a high frequency power supply 27 for applying an AC voltage between the two electrodes.
(Including a matching box for performing impedance matching if necessary). The cathode 24 is formed in a roll shape and can rotate in synchronization with the transport of the fluororesin film 1. The cathode 24 is made of a shielding material 28.
, So that processing can be performed only on the opening.

Atmospheric gas can be supplied to the depressurized container 22 through a valve 23, and exhaust can be performed from the exhaust pipe 21 by a vacuum pump or the like. At this time, the pressure of the atmosphere can be known by the pressure gauge 30.

The transport mechanism is constituted by a feeding section 25a and a winding section 25b of the fluororesin film 1,
The fluororesin film 1 is transported while being in contact with the rolled cathode 24.

When a dark area is formed in the space near the fluororesin film 1 and a plasma area is formed on the anode 29 side (low-temperature plasma) by the high voltage applying means, positive ions are accelerated to the cathode 24 side, It collides with the surface of the fluororesin film 1, and the etching is performed by the impact.

When a sputter etching process is performed using an ion beam, ion beam irradiation means is used. The ion beam irradiation means includes an ion generating section and a section for accelerating and extracting generated ions. Details of such an apparatus and processing conditions are disclosed in, for example, “Surface Modification Technology Dry Process and Its Application” (published by Nikkan Kogyo Shimbun, published in 1988) edited by the Society of Precision Engineering.

(Discharge treatment) The discharge treatment is performed in an atmosphere containing unsaturated hydrocarbons. Examples of the form of the discharge treatment include various discharges that can generate plasma such as glow discharge and corona discharge (so-called plasma discharge), and various discharges that can activate molecules in a gas phase or fluororesin. Can also be adopted. These are disclosed in JP-B-37-17485, JP-B-49-12900, and U.S. Pat. No. 3,296,011. Further, the pressure of the discharge atmosphere may be set to a pressure corresponding to the above-described various discharges. As the surface reforming device for performing the discharge treatment, a device according to the form and pressure of various kinds of discharge treatment may be appropriately selected.

The atmosphere in which the discharge treatment is performed contains unsaturated hydrocarbons. Examples of unsaturated hydrocarbons include alkenes such as ethylene, propylene and butylene, and alkynes. Preferably, it is at least one selected from alkynes having 2 to 4 carbon atoms. Examples of such alkynes include acetylene, methylacetylene, 1-butyne, and 2-alkyne.
Butyne and the like. Among them, acetylene is most preferable for the above-mentioned reason.

Other components contained in the discharge atmosphere include helium, argon, neon, krypton, and the like.
A rare gas such as xenon or an inert gas such as nitrogen may be used. Further, a reactive organic compound or an inorganic compound may be contained as long as the effect of the present invention by addition of the alkyne is not impaired.

Hereinafter, a preferred embodiment of the present invention will be described with reference to an example in which a fluororesin film is subjected to an atmospheric pressure plasma treatment. FIG. 2 is a schematic configuration diagram of an example of an apparatus used for atmospheric pressure plasma processing. The apparatus includes a high-voltage applying means for forming a plasma discharge, a processing chamber 11 for introducing and discharging a gas to maintain an oxygen concentration and a pressure, and introducing acetylene or a mixed gas containing acetylene into a discharge space. And a transport mechanism for feeding and winding the fluororesin film 1 while transporting it.

The high voltage application means is composed of the high voltage application side electrode 3 connected to the high frequency power supply 9 and covered with the dielectric 3a, and the ground side electrode 2a provided below the silicon rubber layer 2b of the main roll 2. You. An inert gas cylinder 10b is connected to the processing chamber 11 via a flow meter 10a, exhausted from an exhaust port 8, and an oxygen concentration and a pressure are monitored by a vacuum gauge 6 and an oxygen concentration meter 7. You. A supply means of acetylene or the like includes a gas cylinder 4c of acetylene or the like, a flow meter 4
b and the nozzle 4c. The transport mechanism includes a feeding unit and a winding unit (not shown) of the fluororesin film 1, a rotating roll 5 a provided at an entrance and an exit of the processing chamber 11, and a main roll 2 facing the high-voltage application side electrode 3.
It is composed of support rolls 5b provided before and after that.

The shape of the high-voltage application electrode 3 is not particularly limited, but when the object to be processed is a wide film, a rod-shaped object is preferable because a uniform processing can be performed. Ground electrode 2
The a (main roll 2) preferably has a cylindrical shape because it also has a function of transporting the fluororesin film 1, which is an object to be processed. The distance between the electrodes is set to 1 to 5 mm, and -10 to the set value.
% To + 10% is preferable for stabilizing discharge. If it is less than 1 mm, it is difficult to maintain the uniformity of the distance between the electrodes, and if it is more than 5 mm, the voltage load tends to increase. The variation of the distance between the electrodes is -10 against the set value.
If it exceeds% to + 10%, a short circuit tends to occur at the shortest part between the electrodes. The high frequency power supply 9 is used for voltage application, and the frequency can be arbitrarily selected from a low frequency (kHz), a high frequency (MHz), and a microwave (GHz). Since it becomes difficult, 200 kHz or less is preferable. In addition, the frequency is preferably 1 kHz or more in order to efficiently perform a polymerization reaction of a single gas or a composite gas containing an acetylene gas. More preferably, 20 to
80 kHz. Even in the case of low frequency, it is preferable to coat one or both of the electrodes with a dielectric such as glass, rubber, ceramics, etc. in order to prevent arc discharge.

The processing chamber 11 is filled with an inert gas such as argon, helium, or nitrogen to adjust the oxygen concentration and the pressure so as to discharge an inert gas introduction system, an acetylene-containing additive gas, and its decomposition gas. It is preferable to use a hermetic type in which an exhaust system is installed for the purpose. For this reason, when the fluororesin film 1 to be treated is guided from the atmosphere outside the processing, the entrance and the exit of the conveyance are coated with a metal having a low frictional resistance such as chrome plating to prevent air from being mixed. It is preferable to sandwich the film between the rolls 5a. When the film is conveyed between rolls having a large frictional resistance such as rubber at both the entrance and the exit, the adhesive strength after treatment tends to decrease.

The oxygen concentration in the processing chamber 11 is 1 to 1000 pp
m, preferably 5 to 200 ppm. If it is less than 1 ppm, it is difficult to adjust the oxygen concentration.
If it is more than 00 ppm, the adhesive strength with the adhesive tends to decrease. The pressure is preferably 500 to 1000 torr. If the pressure is less than 500 torr, it is difficult to adjust the pressure.
If it is larger than 00 torr, the discharge tends to be difficult to stabilize.

The blowing position of the nozzle 4a depends on the introduction amount of acetylene or the like, but the blowing port of the nozzle is directed to the plasma discharge region and 1 to 50 mm from the intersection of the plasma discharge region and the fluororesin film. It is preferable that the outlet is present at a distance of. If it is less than 1 mm, the distribution difference of acetylene in the plasma region becomes large, and this tends to lead to variations in processing and adhesive characteristics. If it is larger than 50 mm, the uniformity of the treatment increases, but the gas concentration tends to be low and the adhesive properties tend to be low. In order to eliminate such a decrease in concentration, a cover may be provided in the vicinity of the discharge region so that acetylene or the like is supplied into the cover and a part of the cover is exhausted.

Further, the amount of acetylene introduced varies depending on the plasma discharge region and the processing speed. However, a fluororesin film having a base material width of 250 mm is placed between an aluminum electrode having a thickness of 20 mm and a width of 300 mm and a ground electrode having a diameter of 100 mm and a width of 400 mm. When passing through the plasma region at a transport speed of 1 m / min for processing, the amount of acetylene introduced is 0.1 to 10 L / mi.
n is preferred. If it is less than 0.1 L / min, the amount of the functional group formed is small, and the adhesive strength with the adhesive tends to decrease. If it is more than 10 L / min, a powdery decomposition product is apt to be deposited, whereby the adhesive strength tends to be hardly developed. Such an introduction amount substantially corresponds to 0.01 to 10% by volume in the concentration of acetylene in the discharge region.

The type of the adhesive for bonding the surface-modified fluororesin film or the like may be appropriately selected according to the type of the rubber or the adhesive as the mating material. The partner material is NR,
For NBR rubber, a halogen polymer-based adhesive can be used as a silicone-based adhesive, for a fluorine-based rubber, a silane coupling agent can be used, and for a urethane-based rubber, a phenol-based adhesive can be used.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and the like showing specific configurations and effects of the present invention will be described below. In addition, the evaluation data in each Example etc. is based on the following evaluation method.

(Epoxy Adhesive Strength) A steel plate and a film were adhered with a roller using a mixture of a main agent of epoxy adhesive (manufactured by Konishi Co., Bond E) and a curing agent in a ratio of 1: 1. Heating was performed for 1 hour to bond them. Thereafter, the film was peeled at an angle of 180 °, and the peel strength at that time was measured.

Example 1 Using a device as shown in FIG.
Film (No900, cutting type, Nitto Denko Corporation)
) At a pressure of 0.01 torr (no gas introduced), a frequency of 13.56 MHz, and a discharge energy of 3 Watt / cm.
^{2. A} sputter etching process was continuously performed at a speed of 1 m / min. The roll on which the treated PTFE film was wound was taken out of the apparatus and subjected to the following discharge treatment.

That is, nitrogen was introduced into the processing chamber at 100 L / min as an inert gas using an apparatus as shown in FIG.
An atmosphere with an oxygen concentration of 50 ppm was created, and an alternating voltage of 50 kHz and a voltage of 13 kv was applied between a rod-shaped aluminum anode covered with a dielectric and a cathode (roll-shaped ground-side electrode) covered with silicon rubber to discharge. Was. Acetylene gas was introduced into the discharge space at a flow rate of 2 L / min (the acetylene concentration in the discharge region was about 2% by volume), and at the same time, PTFE was used.
With the sputter-etched surface of the film facing the anode side,
The back surface was brought into contact with the cathode and transported at a speed of 1 m / min.

The epoxy adhesive strength of the 180 ° peel after the treatment was 0.9 kg / cm. The epoxy adhesive strength after rubbing the treated surface after atmospheric pressure plasma three times with a load of 18 g / cm ² using Bencott (70% by weight of cotton cellulose + 30% by weight of polyester) manufactured by Asahi Kasei Corporation was also 0.1. 9 kg / cm was maintained.

Next, a metal plate G is coated on a steel plate and dried,
1.5 phr sulfur, 40 phr carbon, 5p zinc oxide
hr, 1 phr of stearic acid, 2 phr of accelerator and N
2 mm thick made of unvulcanized nitrile butadiene rubber (NBR) containing 100 phr of BR (low nitrile type)
The NBR and the metal-coated G coated film-treated surface are brought into contact with each other, and a pressing pressure of 50 kg /
The NBR was vulcanized to a thickness of 1.5 mm at a temperature of 150 ° C. for 10 minutes at a temperature of 150 cm ² . Subsequently, the treated film was peeled from the steel plate at 180 ° peel. The peeling force at this time is 2.
At 8 kg / cm, cohesive failure of rubber occurred. Also, the peeling force of the treated film rubbed under the above conditions was 2.2 kg / cm, which resulted in cohesive failure of rubber.

Comparative Example 1 In Example 1, without performing the atmospheric pressure plasma treatment,
Only the sputter etching process was performed. As a result, the epoxy adhesive strength was 0.9 kg / cm, which was the same as that of Example 1, but the epoxy resin having a Bencott friction was 0.5 kg / cm.
And a significant decrease in adhesiveness was observed. Also, NBR
The adhesive strength with 2.8 kg / cm was the same as that of Example 1 due to the cohesive failure of rubber, but the one with Bencot friction was 0.5 kg / cm, and an extremely low adhesion was observed. .

Therefore, it was found that the present invention significantly improved the effect of improving wear resistance.

Comparative Example 2 The same process as in Example 1 was performed except that the sputter etching process was not performed. As a result, the epoxy adhesive strength after the treatment was easily peeled at 0.2 kg / cm. Therefore, it is understood that a high adhesiveness can be stably obtained by using the sputter etching process and the discharge process together as in the present invention.

Test Example 1 Using the treated films obtained in Example 1 and Comparative Example 1,
The adhesion between the treated surface and various types of rubber base adhesives was evaluated. At that time, the evaluation was performed in the same manner as in the evaluation of the rubber adhesion in Example 1. Table 1 shows the results.

[0057]

[Table 1] 1) Chemloc: manufactured by Road Far East Incorporated, Inc. Metalloc: manufactured by Toyo Chemical Laboratory Co., Ltd. As is clear from the results in Table 1, according to the combined treatment as in the present invention, various types of adhesives for rubber bases were used. It was also found that the effect of improving the adhesion was great. In this case, it is clear that the effect of improving the wear resistance according to the present invention can be obtained.

Test Example 2 Using the treated films obtained in Example 1 and Comparative Example 1,
ESCA measurement was performed on the treated surface under the following measurement conditions and the like, and changes in the surface composition were examined.

(Measurement conditions, etc.) Measuring device: Shimadzu / Kratos, AXIS
-HSi X-ray source: AlKα (using monochromator) Output: 150 W (15 kV) Extraction angle: 90 ° with respect to the sample surface Measurement area: 300 × 700 μm Binding energy: 292.5 e at the peak top of C1s
The shift was corrected as V (CF ₂ ).

As a result, in the film of Comparative Example 1, carbon atoms were 34.0%, oxygen atoms were 1.0%, and fluorine atoms were 64%.
4%, whereas the film of Example 1 had 80.2% of carbon atoms, 14.3% of oxygen atoms, and 1.6% of fluorine atoms.
%Met. Therefore, it was found that by the discharge treatment after the sputter etching treatment, the fluorine atoms were almost carbonized and the amount of oxygen atoms was increased, thereby improving the wear resistance and the adhesion.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an apparatus used for a sputter etching process.

FIG. 2 is a schematic configuration diagram of an example of an apparatus used for atmospheric pressure plasma processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluororesin film 2a Grounding side electrode 3 High voltage application side electrode 4c Gas cylinder of acetylene etc. 22 Pressure reducing container 24 Cathode 29 Anode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshihiko Ariyoshi 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Kazuyoshi Uemori 1-1-1, Shimohozumi, Ibaraki-shi, Osaka No. 2 Nitto Denko Corporation F-term (reference) 4F073 AA01 BA16 BB01 CA22 CA49 CA63 FA01 FA02

Claims (2)

[Claims] 1. A method for modifying the surface of a fluororesin molded product, comprising subjecting a surface of the fluororesin molded product to a sputter etching treatment and then performing a discharge treatment in an atmosphere containing an unsaturated hydrocarbon. 2. The surface modification method according to claim 1, wherein the fluororesin molded product is a polytetrafluoroethylene (PTFE) film or sheet.