JPS6033860B2 - Fluororesin film with adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluororesin film with adhesive.

Among plastic films with adhesives, those in which the plastic film is a fluororesin film and the adhesive is a thermosetting adhesive have excellent heat resistance as well as the plastic film and adhesive. Because of its chemical resistance, etc., it has a wide range of uses.

For example, it can be used for flat printed cables that require heat resistance, or for coating the inner surface of containers that require heat resistance and chemical resistance. However, the surface of the fluorine-adhesive film is extremely inert, and the adhesive force between the film surface and the thermosetting acid adhesive layer is weak in the adhesive-coated fluororesin film. There is a concern about peeling at the adhesive interface.

As a method for activating the surface of fluororesin molded products,
It is known to treat the surface with chemicals such as sodium in liquid ammonia solution.

However, since this method uses sodium, it is difficult to handle the used processing solution, which poses a risk of igniting a fire during processing. The treated surface of the fluororesin film turns brown and the product value inevitably decreases. In addition to the disadvantage that the electrical resistance of the surface of the film is reduced, there is also the disadvantage that when the treated surface is exposed to ultraviolet rays, the treatment effect is significantly reduced. In view of the above situation, the present inventors conducted extensive research and found that if the surface of a polyurethane resin film is subjected to sputter etching treatment under atmospheric pressure conditions of 0.0005 to 0.5 Torr, the same surface can be thermally cured. The present inventors have discovered that a fluororesin film with an adhesive can be firmly attached to the adhesive layer without the above-mentioned difficulties, and have proposed the adhesive-coated fluororesin film of the present invention.

That is, the adhesive-attached fluororesin film according to the present invention has the surface of the fluororesin film exposed to an atmospheric pressure of 0.0005.
Sputter etching treatment under ~0.5Ton conditions,
This structure is characterized in that a thermosetting adhesive layer is provided on the treated surface.

In the present invention, examples of the fluorine-compatible resin film include polymers of fluorine-based monomers such as tetrafluoroethylene, trifluoroethylene, and hexafluoropropylene, or copolymers of these monomers and olefins. Molded products of polytetrafluoroethylene and fluoroethylenepropylene polymers are particularly effective.

As mentioned above, the atmospheric pressure when sputter etching a fluororesin film is 0.0005 to 0.5 at room temperature.
Torr, preferably 0.001 to 0.15T
It's on.

The distance between the electrodes is determined in proportion to approximately 1/P (P is pressure Torr), and is approximately 100 cm when the atmospheric pressure is 0.005 Torr, for example. Other sputter etching processing conditions include a frequency of several hundred KHZ to several tens of MHZ;
The normal frequency is 13.53 MHZ, which is the industrially allocated frequency. The discharge power is 0.1 to lOWatt/. As for the processing time, the smaller the discharge power is, the longer it is necessary to make it. Practically speaking, it is desirable to increase the discharge power and shorten the processing time. To give an example, the processing time in the case of 5Watt/unwanted is 1 second or more, preferably 2 seconds to 1 minute,
Therefore, the product of discharge power and processing time is 5Watt・Se
c/enemy or higher, preferably lOWatt・Sec/c style~
300 Watt Sec/c tiger is good. The atmospheric pressure can also be maintained at the above pressure while introducing a gas. In this case, the gas may be an inert gas such as argon, air,
Nitrogen, water vapor, carbon dioxide, ammonia, etc. are used. Furthermore, treatment can be performed using only decomposed gas without introducing gas.

As the sputter etching apparatus, for example, the one shown in FIG. 1 is used.

In FIG. 1, 1 is an exhaust pipe connected to a vacuum pump (not shown) for exhausting the gas in the reduced pressure vessel 2, 3 is a valve for introducing atmospheric gas into the reduced pressure vessel 2, and 4 is a fluorine gas pipe. It is an electrode for sputter etching the resin film 5, and is connected to the external matching box 6 with a lead wire.
(impedance matching device), and is further guided to a high frequency power source 7.

Reference numeral 8 denotes a shielding electrode for the electrode 4, which is suitable for conduction with the ground side of the high frequency power source 7.

Reference numeral 9 denotes a counter electrode, which is also connected to the ground side of the high frequency power source 7.

When a metal reduced pressure container is used as the reduced pressure container 2, this container is connected to the ground side of the high frequency power source 7. The matching box 6 is a circuit consisting of capacitance and inductance, and performs impedance matching. When the potential on the electrode 4 side is negative with respect to the electrode 9, positive ions generated as a result of the discharge are accelerated and collide with the surface of the fluororesin film 5, thereby performing sputter etching. At this time, the positive charges possessed by the colliding brass ions accumulate on the surface of the fluororesin film 5 and the surface potential increases, so the potential difference between this surface and the electrode 9 becomes 4, maintaining the discharge. It becomes difficult to do. However, during a half cycle of the high frequency voltage, the potential on the electrode 4 side becomes positive with respect to the electrode 9, so electrons enter the surface of the fluorinated olefin copolymer molded article 5 from the discharge space, and the electrons have a negative potential. Neutralizes positive ions that have accumulated on the surface due to electric charge. As a result, when the potential on the electrode 4 side becomes negative with respect to the electrode 9 in the next half cycle of the high-frequency voltage, the potential difference between the two is large and discharge occurs, and the generated positive ions are accelerated and fluorinated. It collides with the surface of the olefin copolymer molded article 5 to enable sputter etching.
The above steps are repeated for each cycle of the high frequency voltage, and the surface of the fluorinated olefin copolymer molded article 5 is sputter-etched. To briefly describe an example of the sputter etching process, a fluororesin film 5 is placed on the electrode 4 shown in FIG. Atmosphere gas is introduced and adjusted to 1 x 10-2 Tom, and the high frequency power source is adjusted so that the discharge power is 0.5 Watt, and sputter etching is performed for several seconds to several tens of seconds.

In order to continuously perform the surface treatment of the fluororesin film, a sheet winding drive device may be installed in the vacuum container 2, as shown in FIG. 2, for example.

In addition, in the figure, 51 is a fluororesin film, 10 is a supply roll, and 11 is a winding roll. Figure 3 is a 400-degree enlarged photo showing the surface condition of the fluororesin film that has been sputter-etched as described above.The surface has minute acicular unevenness, and this acicular unevenness improves adhesive strength. greatly contributes to As shown in Comparative Examples 1 and 2, which will be described later, in other plastics, the surface does not become uneven due to sputter etching, and the surface only changes chemically, but in fluororesin films, chemical In addition to the change, there is also the occurrence of acicular unevenness, and this unevenness has a great effect of improving adhesion. In the present invention, in order to provide a thermosetting adhesive layer on the surface of a fluororesin film subjected to sputter etching as described above, the thermosetting resin composition is made into a solution with an appropriate solvent, and this solution is rolled. The coating is applied by a conventional coating method such as coating, reverse coating, knife coating, or globia roll coating, and the coating is heated to volatilize and remove the solvent.

In this case, the thermosetting resin coating layer may be provided in either an uncured state or a semi-cured state. For the thermosetting resin composition, any suitable thermosetting resin such as epoxy resin or phenol resin can be used, but in order to impart flexibility, a rubber component such as acrylonitrile butadiene rubber may be added. It is preferable.

In order to reduce the cost and shrinkage of thermosetting adhesives, we add fillers such as clay, silica, calcium carbonate, silica, barium carbonate, etc. to paper, cloth, glass paper, and glass. A base film or sheet for lamination such as fiber cloth can also be embedded in the adhesive layer. Furthermore, additives such as heat stabilizers, anti-aging agents, and curing accelerators can be added as necessary. As shown in FIG. 3, the adhesive-attached fluororesin film according to the present invention is a film in which a thermosetting adhesive is applied to a finely textured film surface. Due to chemical changes on the film surface due to ions, electrons, and extreme ultraviolet light generated during sputter etching, the interfacial adhesive force between the film and the adhesive layer is extremely large. A simple glow discharge treatment does not make the surface of the fluororesin film uneven, so the above-mentioned excellent interfacial adhesion cannot be obtained. That is, according to the present invention, the discharge treatment is carried out in the cathode dark region where the ion energy of the discharge region is extremely high, and under the specified conditions as described above.

The ion energy in the dark part of the cathode is about 10 to 100 times greater than the ion energy of a simple glow discharge in which discharge processing is performed in plasma. Therefore, the surface of the fluororesin film can be subjected to a good surface treatment in a short time, and a strong adhesive surface can be obtained. Furthermore, the above-mentioned interfacial adhesion of the film of the present invention is superior to that of a fluororesin film whose surface is treated with the chemicals mentioned above, and overcomes all the difficulties mentioned above when treating with chemicals. It can be resolved.

In the present invention, it is also possible to sputter-etch both sides of a fluororesin film and provide a thermosetting adhesive layer on each treated side.Examples of the present invention will be described below.

Example 1 A cut polytetrafluoroethylene sheet with a thickness of 0.2 ribs was set in a device as shown in Fig. 1 (distance between electrodes: 11 ribs), and the inside of the container was heated to 1 x 10-5 Torr using a vacuum pump.
After reducing the pressure to below r, argon was introduced through a valve to maintain the atmospheric pressure at 5×10-orr.

Next, a high frequency voltage of 13.5 MH2 was applied, and sputter etching was carried out under a discharge power of 4.0 Watts per carp. After the power was turned off, air was introduced into the container through a valve to bring it to normal pressure. I returned it. On the other hand, bisphenol type epoxy resin (manufactured by Shell Petrochemical Co., Ltd., trade name: Epiquat) 10
Ikaribe, 30 Ikaribe, carboxy-modified acrylonitrobutadiene rubber (manufactured by Nippon Zeon Co., Ltd., trade name: Nibol 1072) and 400 parts of methyl ethyl ketone were lit for 6 hours,
An adhesive resin solution was created.

This resin solution was applied to the sputter-etched surface of the polytetrafluoroethylene sheet described above using an applicator, and dried at 13,000°C for 10 minutes to form an adhesive layer.

The adhesive strength of the sample obtained in this way was determined according to JIS-C-211
7, the sample was placed on a 35-layer copper foil with the adhesive layer side facing up to 170qo, 50k9/
Pressing was carried out for 1.5 hours under normal heating and pressure conditions, and the adhesive strength of the thus obtained measurement sample was measured and found to be 1.0.
It was K9/depression.

Example 2 A cut polytetrafluoroethylene sheet with a thickness of 0.2 mm was set in the apparatus shown in Fig. 1 (distance between electrodes 11 mm), and the atmospheric pressure in the container was increased to 5 × 10 mm using a vacuum pump.
-Kept at 汀orr.

Next, a high-frequency voltage of 13.5 aMHZ was applied, and a sand sputter etching process was performed under a discharge power of 2.0 Watt/ground, the power was cut off, and air was introduced into the container from the valve to bring it to normal pressure. I returned it.

On the other hand, 10 parts of Novorazku epoxy type epoxy resin (manufactured by Dow Chemical Co., Ltd., trade name: DEN438), carboxy-modified acrylonitrile-butadiene rubber (manufactured by Nippon Zeon Co., Ltd., trade name: Nipole 1072) and 300 parts of methyl ethyl ketone were added. After 6 hours of rope worship, an adhesive resin solution was created.

Next, in the same manner as in Example 1, an adhesive layer was provided on the sputter-etched surface of the polytetrafluoroethylene sheet, and a measurement test was created in the same manner as in Example 1,
When the adhesive strength was measured, it was 1.1k9/c.

Example 3 A sheet of fluoroethylene propylene polymer with a thickness of 0.2 was set in the device shown in Figure 1 (distance between electrodes 11 mm), and the inside of the container was heated to 1 x 10-5 T using a vacuum pump.
After the pressure was reduced to below orr, air was introduced through a valve to maintain the atmospheric pressure at 5×10-orr.

Next, a high frequency voltage of 13.58 MHZ was applied, and sputter etching was performed for 4 hours under a discharge power of 3.0 Watt/c. After the power was turned off, air was introduced into the container through a valve to bring it to normal pressure. I returned it. On the other hand, ether ester type epoxy resin (manufactured by Dainippon Ink and Chemicals, trade name: Epicron 1030) 10, cariboxy-modified acrylonitrile-butadiene rubber (Nipole 1072) 4
0 and 1 with methyl ethyl ketone and acetone:
750 parts of the mixed solution of No. 1 was stirred for 6 hours to obtain an adhesive solution.

Next, an adhesive layer was provided on the sputter-etched surface of the fluoroethylene propylene polymer sheet in the same manner as in Example 1, and a measurement sample was prepared in the same manner as in Example 1, and the adhesive strength was measured.1. It was 0k9/c.

Example 4 Instead of the discharge power of 4.0 Watt/ground and the processing time of 30 seconds in Example 1, the discharge power was 0.1 Watt.
All other conditions were the same as in Example 1, except that 20 minutes and 20 minutes were used.

Regarding this example product, the same machine as Example 1 was used, and JIS-C-
When the adhesive strength was measured according to 2107, it was 1.05k9/
It was the skin.

In all of Examples 1 to 4 submitted, the generation of fine needle-like irregularities as shown in FIG. 3 was competed.

In order to clarify the unique effect of the fluororesin film in the present invention (the above-mentioned fine acicular unevenness),
Regarding polyethylene film and vinyl chloride film (both film thickness is on the 0.2 side), the above Examples 1 to
Sputter etching treatment was performed under the same conditions as in 4.

However, under the conditions of Examples 1, 2, and 3, all of the films melted due to the high temperature, making sputter etching impossible.

Under the conditions of Example 4, polyethylene film and vinyl chloride film could be treated, but no surface roughness was observed. Comparative Example 1 A polyethylene film with a thickness of 0.2 was subjected to sputter etching under the same conditions as in Example 4.

That is, a polyethylene film with a thickness of 0.2
Set it in the device as shown in the figure (electrode distance 110 side),
After the pressure inside the container was reduced to 1×10 −5 Ton or less, argon was introduced through a valve to maintain the atmospheric pressure at 5×10 −5 orr.

Next, a high frequency voltage of 13.58 MHZ was applied, and sputter etching was performed for 20 minutes at a discharge power of 0.1 Watt/h, and after the power was cut off, air was introduced into the container through a valve to return to normal pressure.

The condition of the treated surface of this comparative example was as shown in FIG. 5A (enlarged photograph at 4,000 yen), and no unevenness was observed. Comparative Example 2 Same as Comparative Example 1 except that a vinyl chloride film was used instead of the polyethylene film of Comparative Example 1.

The condition of the treated surface of this comparative example was as shown in FIG. 5B (4,00M sound magnification photograph), and no unevenness was observed. From the comparison of Comparative Examples 1 and 2 and Example 4 above, it can be seen that the sputter etching process of the present invention causes the fluororesin film to become acicularly uneven, and the accompanying remarkable adhesion improvement effect is due to the unique effects of the fluororesin film. It is clear that

Next, it is clear from Comparative Example 3 below that in the case of normal glow discharge treatment (discharge treatment in a plasma region), the adhesive force cannot be increased even if the amount of electric power is increased.

Comparative Example 3 A cut polytetrafluoroethylene sheet with a thickness of 0.2 skin used in Example 1 was placed approximately in the center of the electrode of a glow discharge treatment device in which the electrode on the side with an interelectrode distance of 160 was provided in a reduced pressure container, 0.01Ton in a water vapor gas atmosphere inside the container
The frequency is 60, the discharge voltage is 7KV, and the discharge current is 2.
Discharge was performed between three inkstone sands under the discharge condition of 0MA.

The electric energy of this discharge is the electric energy used in Examples 1 to 4 (
100 to 120 Watt/ground x Sec). The surface condition of the sheet after this treatment is as shown in Figure 4, and unlike the needle-like uneven surface in the case of Figure 3,
) (Figure 4 has the same magnification as Figure 3). An adhesive layer was provided on this treated sheet in the same manner as in Example 1, and the adhesive strength was measured to be 0.
．． It is only 2k9/skin (in the case of Example 1, it is 1.0k9/skin as described above).

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing a sputter etching apparatus used for surface treatment of the film of the present invention;
The figure is a photomicrograph showing the sputter-etched surface of the film of the present invention, FIG. 4 is a photomicrograph showing the surface condition obtained by treating a fluorinated olefin polymer sheet by ordinary glow discharge, and FIGS. FIG. 5B is a micrograph showing the surface condition obtained by processing in Comparative Examples 1 and 2, respectively. In the figure, 4 and 9 are electrodes, and 5 and 51 are films. Anno diagram〆2 figure 73 figure O44 Ota diagram A Kata diagram B

Claims (1)

[Claims] 1. The surface of the fluororesin film is subjected to an atmospheric pressure of 0.0005
An adhesive-backed fluororesin film characterized in that it is sputter-etched under conditions of ~0.5 Torr to form fine acicular irregularities, and a thermosetting adhesive layer is provided on the treated surface. 2 Discharge power of sputter etching treatment is 0.1 to 10
Watt/cm^2. The adhesive-backed fluororesin film according to claim 1, characterized in that the adhesive is 3. The adhesive-backed fluororesin film according to claim 1, wherein the product of discharge power and processing time in the sputter etching process is 5 watt·Sec/cm^2 or more. 4 The product of discharge power and processing time for sputter etching treatment is 10Watt・Sec/cm^2~300Watt
- The adhesive-backed fluororesin film according to claim 1, characterized in that the adhesive is Sec/cm^2.