JPS62162542A - Polyinide film with fluoroplastic layer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyimide film having a fluororesin layer. More specifically, the present invention relates to a film laminate in which a fluororesin film is laminated on at least one surface of an aromatic polyimide film.

[Background of the Invention] Aromatic polyimide films have been known as resin films with high heat resistance and insulation properties. It is used for many purposes, and new uses are being developed.

As mentioned above, aromatic polyimide film has excellent properties and is a useful resin film, but on the other hand, it has insufficient moldability into arbitrary shapes, and other resins,
There are problems such as insufficient adhesion to other materials and insufficient adhesion between polyimide films.

In particular, the problem with insufficient adhesion of the latter is that the polyimide film is made into a tape, and then it is connected to ordinary copper wire, rectangular WA, etc.
This becomes a big problem when it is used as an insulating coating material by winding it spirally around electric wires such as wires. In other words, there is no adhesive between the overlapping parts of polyimide tape wrapped in a spiral, so if polyimide tape is used as an insulating coating in a state where it is simply stacked like that, it will not be possible to bend the wire or wrap it into a coil. When doing so, "slippage" occurs in the overlapping part of the tape,
There is a problem that insulation failure is likely to occur.

In consideration of the above-mentioned problems, attempts have already been made to impart adhesiveness to the surface of aromatic polyimide films, and one representative example is One example is a method in which fluororesin films whose surfaces have been subjected to discharge treatment are laminated under heating to form an adhesive layer.

The present inventor has conducted research with the aim of improving the surface adhesion of aromatic polyimide films.
We have found that the method of simply applying a fluororesin film whose surface has been subjected to electrical discharge treatment as an adhesive layer does not provide sufficient adhesion to polyimide films that are processed or used under harsh conditions. .

In particular, if the polyimide of the aromatic polyimide film is of a type in which the main acid skeleton is biphenyltetracarboxylic dianhydride, the lamination of the fluororesin film adhesive layer by the above method will not result in practically satisfactory adhesion. It was found that no gender was assigned.

[Object of the Invention] The main object of the present invention is to provide an aromatic polyimide film with improved Ta adhesion.

Particularly, an object of the present invention is to provide an aromatic polyimide film of a type in which the polyimide has biphenyltetracarboxylic dianhydride as the main acid skeleton, and which has high adhesive properties. do.

[Summary of the Invention] The present invention provides that a fluororesin film that has been subjected to discharge treatment on the discharge treated surface of an aromatic polyimide film whose surface has been subjected to discharge treatment, and that the discharge treated surface of the aromatic polyimide film is It is made of a polyimide film having a fluororesin layer that is laminated so that the surfaces thereof face each other.

Furthermore, the present invention provides an aromatic polyimide film having an adhesive layer attached to both sides, that is, an aromatic polyimide film having discharge treatment applied to both sides, and a fluororesin resin having discharge treatment applied to at least one surface of the aromatic polyimide film. The present invention also provides a polyimide film having fluororesin layers on both sides, characterized in that the films are laminated with their discharge treated surfaces facing each other.

Note that the term "film" in Part 1 is not used with the intention of specifically specifying the thickness, and the "film" in the present invention is generally referred to as a "thin film", "sheet", etc. This includes any form of M film-like material.

[Detailed Description of the Invention] Aromatic polyimide films obtained from various aromatic polyimides have been known so far, and the polyimide film of the present invention is a film obtained from any such aromatic polyimide. It may be.

Aromatic polyimides are generally composed of an aromatic tetracarboxylic acid skeleton and an aromatic diamine skeleton, and by selecting compounds with various chemical structures for each, aromatic polyimides with various physical and chemical properties can be created. known to be obtained.

That is, the aromatic tetracarboxylic acid skeleton of the aromatic polyimide is 3.3', 4.4'-benzophenonetetracarboxylic acid, and 2,3.3'.

4°-benzophenonetetracarboxylic acid, pyromellitic acid, 3.3', 4.4'-biphenyltetracarboxylic acid, and 2,3.3', 4°-biphenyltetracarboxylic acid, and aromatic groups thereof Examples include carboxylic acid skeletons derived from acid dianhydrides, esters, salts, etc. of tetracarboxylic acids. Of these, 3.3”;
Derived from biphenyltetracarboxylic dianhydride represented by 4.4'-biphenyltetracarboxylic acid dianhydride and 2゜3.3',4'-biphenyltetracarboxylic acid dianhydride. The present invention is particularly effective when an aromatic polyimide film having an acid skeleton as the main acid skeleton is used.

As the aromatic diamine skeleton of aromatic polyimide, halophenyl diamine, metaphenylene diamine, 2,4
-diaminotoluene, 4,4'-diaminodiphenyl ether, 4,4°-diaminodiphenylmethane, 0-)
Lysine, 1,4-bis(4-aminophenoxy)benzene, 0-tolidinesulfone, bis(aminophenoxy-
phenyl)methane and bis(aminophenoxy-phenyl)sulfone.

There are also various methods for producing polyimide using the above aromatic carboxylic acid component and aromatic diamine component. For example, a method for obtaining a polyimide by heating the above-mentioned aromatic carboxylic acid component and aromatic diamine component dissolved in an organic polar solvent to perform polymerization and imidization in a one-step reaction, and and an aromatic diamine component dissolved in an organic polar solvent, a polymerization reaction is caused at a low temperature near room temperature to form a polyamic acid, and this amic acid is formed into a coating film and imidized to form a film. Methods for obtaining polyimide are known.

The aromatic polyimide used in the present invention may be obtained by any method.

As mentioned above, the technology of attaching a fluororesin film to the surface of an aromatic polyimide film to form an adhesive layer is already known. The fluororesin film used in the present invention may be a film molded from any fluororesin. good.

Examples of fluororesins that can be used in the production of the fluororesin film of the present invention include copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), fluoroalkoxyethylene 41 resins (P
FA), fluorinated ethylene propylene ether resin (E
PE), and tetrafluoroethylene resin (TFE).

Discharge treatment methods for the surface of a fluororesin film are already known, and for example, a method of generating corona discharge or plasma discharge on the surface of a fluororesin film is commonly used. The conditions for the discharge treatment are determined in consideration of the surface condition required of the fluororesin film after treatment, and the physical properties and strength of the film. In any case, these discharge treatment operations and conditions are appropriately determined according to known techniques.

Although it is not known about the discharge treatment of the surface of aromatic polyimide film, according to the research of the present IJI researcher, it can be done under the same operation and conditions as the discharge treatment of conventionally known heat-resistant synthetic resin films. It was found that the discharge treatment on the surface of aromatic polyimide film was a part of the process.

Therefore, for the main treatment of the surface of the aromatic polyimide film, a method of generating corona discharge or plasma discharge on the surface can be used. The conditions for the discharge treatment can be determined in consideration of the surface condition required of the aromatic polyimide film after treatment, the physical properties 1 strength of the film, and the like. That is, when the amount of discharge increases, the adhesiveness or activity of the treated surface improves, but the strength of the film decreases and other physical properties may also decrease. On the other hand, if the amount of discharge is small, the adhesion or activity of the treated surface will not be sufficiently improved. Therefore, the treatment operations and conditions are appropriately determined in consideration of these fluorescences. For example, when using corona discharge, the amount of applied current is 20 to 3
It is preferable to select from the range of 00 W/ln'·min.

Lamination of a fluororesin film onto a polyimide film can be carried out, for example, by the following operation.

A polyimide film and a fluororesin film are overlapped, and a press roller consisting of a metal roller and a rubber roller is used to apply pressure of 0.5 to 5.0 kg/Crrr' and temperature of about 50 to 250°C (preferably about 80 to 80°C). Pressure bonding is performed at a temperature of 200°C. The bonded laminate is then separated by approximately 250
A temperature of ~450°C (preferably about 300-400°C) (
A heat treatment is performed at a maximum temperature of 0.5 to 5 minutes without applying pressure.

In the present invention, the fluororesin film may be provided on only one side of the aromatic polyimide film, but when used in applications requiring adhesion between polyimide films, such as when used as an insulating coating material for electric wires, for example, Alternatively, one fluororesin film may be laminated on both sides of the aromatic polyimide film.

An example of the structure of an aromatic polyimide film having a fluororesin layer according to the present invention is shown in the attached drawings.

FIG. 1 shows that a fluororesin film 12 whose one surface 12a has been subjected to an electric discharge treatment is placed on the discharge treated surface 11a of an aromatic polyimide film 11 whose one surface 11a has been subjected to an electric discharge treatment. 12a is a Mi layer formed so as to face the discharge-treated surface 11a of the polyimide film.

FIG. 2 shows that a fluororesin film 22 whose both surfaces 22a and 22b have been subjected to discharge treatment is placed on the discharge treated surface 21a of an aromatic polyimide film 21 whose one surface 21a has been subjected to discharge treatment. 22a shows a structure in which 8i layers are formed so as to face the discharge-treated surface 21a of the polyimide film.

FIG. 3 shows a discharge treated surface 31a of an aromatic polyimide film 31 whose both surfaces 31a and 31b have been subjected to discharge treatment, and a fluororesin film 32 whose both surfaces 32a and 32b have been subjected to discharge treatment. shows a structure in which the polyimide films are laminated so as to face the discharge-treated surface 31a.

FIG. 4 shows the discharge-treated surfaces (both sides) of an aromatic polyimide film 41, which has been subjected to discharge treatment on both sides 41a and 41b.
Two fluororesin films 42, 43 each having one surface 42a, 43a subjected to discharge treatment are arranged such that the discharge treated surfaces 42a, 43a face the discharge treated surfaces 41a, 41b of the polyimide film. It shows a stacked structure.

FIG. 5 shows that on the discharge treated surfaces (both sides) of an aromatic polyimide film 51 whose both sides 51a and 51b have been subjected to discharge treatment,
Two fluororesin films 52 and 53, each of which has been subjected to discharge treatment on both sides 52a, 52b, 53a, and 53b,
A configuration is shown in which the discharge treated surfaces 52a and 53a are laminated so as to face the discharge treated surfaces 51a and 51b of the polyimide film.

[Effects of the Invention] The aromatic polyimide film having a fluororesin layer of the present invention has excellent adhesion between the fluororesin layer and the polyimide film, so it can withstand harsh conditions such as application of strong shearing force. Even when the fluororesin layer and the polyimide film are placed on the bottom, undesirable phenomena such as peeling or "slippage" between the fluororesin layer and the polyimide film are less likely to occur.

Furthermore, since the IJI strength of the aromatic polyimide film having a fluororesin layer of the present invention exhibits high water resistance, there is also the advantage that there is little decrease in bonding strength even if the bonded state is left in the atmosphere for a long period of time. The aromatic polyimide film having a fluororesin layer of the present invention can be used very advantageously in practice.

In addition, heating is usually performed when laminating a fluororesin film to an aromatic polyimide film, but the heating conditions are also compared to those used in conventional lamination methods, in which the surface of the polyimide film is laminated without electrical discharge treatment. This can be carried out under mild conditions, for example, relatively low temperature conditions, and therefore, it is possible to effectively reduce thermal deterioration between the fluororesin film and the aromatic polyimide film that tends to occur during lamination operations under heated conditions. I can do it.

[Example] [Example 1] A copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), which was treated with corona discharge on both sides, was used as a fluororesin film.
) long film (@500mm, thickness 12-5gm
) was prepared.

3.3' as an aromatic polyimide film.

4. A long polyimide film produced from a polyimide solution (P-chlorophenol solution) obtained by polymerizing and imidizing 4°-biphenyltetracarboxylic acid dianhydride and 4,4-diaminodiphenylnitrate. (radius 500 mm, thickness 12.51 Lm) was prepared, and both surfaces thereof were subjected to discharge treatment under the conditions listed in Table 1.

A fluororesin film was layered on one side of the aromatic polyimide film, and the film was pressurized by passing continuously between a metal roller and a rubber roller heated to 130°C under a pressure of 1.9 kg/crn. heated to 375℃ for 1 minute,
Thereby, the fluororesin film was laminated onto the polyimide film to obtain a laminated film.

[Comparative Example 1] A laminated film in which a fluororesin film was laminated on a polyimide film surface was obtained in the same manner as in Example 1 except that the surface of the polyimide film was not subjected to discharge treatment.

[Evaluation of Adhesive Strength of Laminated Film 1 Regarding the obtained laminated film, the adhesive strength between the polyimide film and the fluororesin film (laminate strength)
was measured. This adhesive strength measurement was performed using a test piece (10 mm
The T-peel strength was measured using a tensile testing machine under the conditions of a chuck interval of 50 mm and a tensile speed of 100 mm/min.

In addition, two laminated films were prepared, and the polyimide film surface of one bt layer film and the fluororesin film of the other laminated film were superimposed, and this was sealed using a heat sealer with upper and lower heating plates. crrr? The overlapping portions were joined by heating at 350° C. for 20 seconds while applying a pressure of . The adhesive strength (joint strength) of this joint was determined by measuring the T-peel strength under the same conditions as above. The results obtained are shown in Table 1.

Note that the measurements were performed on five test pieces prepared from the same sample. The measured values shown in Table 1 are the average values of the measured values of five test pieces.

Table 1 Discharge treatment Laminate bonding strength (w/m″
/min) Strength (g/cm) (g/am) Example 1
150 200 or more 280 Comparative Example 1 None 40 180 [Example 2, Comparative Example 2
] The same fluororesin film (discharge treated on both sides) and aromatic polyimide film (discharge treated on both sides under the conditions listed in Table 2) used in Example 1 were prepared.

A fluororesin film was layered on one side of the aromatic polyimide film, and heated at 130°C under a pressure of 1.9 kg/cm''.
The film was continuously passed between a heated metal roller and a rubber roller to apply pressure, and then heated to 375°C for 1 minute, thereby laminating the fluororesin film onto the aromatic polyimide film. Next, a fluororesin film was layered on the other side of the aromatic polyimide film, passed between rollers in the same manner, and then heated, thereby laminating the fluororesin film on both sides of the aromatic polyimide film. A laminated film was obtained.

Regarding the obtained laminated film, the lamination strength (adhesion strength between the polyimide film and the first laminated fluororesin film) and bonding strength (the difference between the fluororesin film surface of one test piece and the fluororesin film of the other test piece) The adhesion strength to the surface was measured by the method described in the above examples. The results obtained are shown in Table 2.

Below is the margin 2nd table Discharge treatment Laminate bonding strength (w/m″
/min) Strength (g/a) (g/cm) Example 2
150 200 or more 650 Comparative Example 2 None 110 440 [Evaluation of water resistance of laminated film] The same test piece (test piece obtained by bonding the laminated film) as the test piece used in the above test for bonding strength evaluation was tested. After being placed in boiling water for 4 hours, a similar test was conducted to evaluate bonding strength. The results are shown in Table 3.

Measurements were performed on five test pieces prepared from the same sample. The measured values shown in Table 3 are the average values of the measured values of five test pieces.

Table 3 (Changes in bond strength due to boiling water treatment) Discharge treatment Bond strength After boiling water treatment (W/g/min)
(g/c layer) Strength retention example 2150
565 87% Comparative Example 2 None 31
0 70% [Example 3, Comparative Example 3] As a fluororesin film, a long film (width 500 mm, thickness 12.5 m) of fluorinated alkoxyethylene resin (PFA) 17) which had been subjected to corona discharge treatment on both sides was used. Prepared.

The same aromatic polyimide film as used in the above examples (both sides of which were subjected to discharge treatment under the conditions listed in Table 4) was prepared.

A fluororesin film was laid on one side of the aromatic polyimide film, and the film was passed between a metal roller and a rubber roller under a pressure of 1.9 kg/crm'.
This was heated in batches to 355°C, thereby laminating the fluororesin film onto the aromatic polyimide film.

Regarding the obtained laminated film, the lamination strength (adhesive strength between the polyimide film and the fluororesin film)
The bonding strength (adhesion strength between the polyimide film surface of one test piece and the fluororesin film surface of the other test piece) was measured by the method described in the above example. The results obtained are shown in Table 4.

Table 4: Discharge treatment Laminate bonding strength (w/m″
/min) Strength (g/c■) (g/c) Implementation-Example 3 50 200 or more 370 Comparative Example 3
None 137 15 [Examples 4 to 7] Example 1 except that the amount of discharge treatment in corona discharge was changed to the value shown in Table 5, and heating during lamination was performed at 335°C.
In the same manner as above, a laminate in which a fluororesin film was laminated on one side of an aromatic polyimide film was produced.

Regarding the obtained laminated film, the lamination strength and bonding strength were measured in the same manner. The results obtained are shown in Table 5.

Table 5 Discharge treatment Laminate bonding strength (w/rn'/
) Strength (g/cm) (g/cm) Example 4
50 200 or more 2605 100
200 or more 3576 150 200 or more
3507 300 200 or more 290

[Brief explanation of drawings]

FIGS. 1 to 5 are schematic diagrams each showing typical structural examples of an aromatic polyimide film having one fluororesin layer according to the present invention. 11.21.31.41.51: Aromatic polyimide film 11a, 21a, 31a, 31b, 41a, 41b, 5
1a, 51b: Discharge treated surface of aromatic polyimide film 12.22.3
2.42.43.52.53: Fluororesin films 12a, 22a, 22b, 32a, 32b, 42a, 4
3a, 52a, 52b, 53a, 53b: Discharge treatment surface of fluororesin film Patent applicant Ube Industries Co., Ltd. Same as above Chukoh Chemical Industries Co., Ltd. Representative Patent attorney Yasuo Yanagawa Ward Ward Ward-〇1
Nozuka Tsuka
Ukiashi Ward@＄h Shirozuka Procedural Amendments March 4, 1986

Claims (1)

[Scope of Claims] 1. A fluororesin film subjected to discharge treatment is placed on the discharge treated surface of an aromatic polyimide film whose surface has been subjected to discharge treatment, and the discharge treated surface is the discharge treated surface of the polyimide film. A polyimide film having a fluororesin layer laminated so as to face each other. 2. A polyimide film having a fluororesin layer according to claim 1, wherein both sides of the fluororesin film are subjected to discharge treatment. 3. The polyimide film having a fluororesin layer according to claim 1, wherein the surface of the aromatic polyimide film on the side on which the fluororesin film is not laminated is also subjected to discharge treatment. 4. Any one of claims 1 to 3, characterized in that the polyimide of the aromatic polyimide film has a carboxylic acid skeleton derived from biphenyltetracarboxylic dianhydride as its main acid skeleton. A polyimide film having a fluororesin layer according to the above item. 5. A fluororesin film whose discharge treatment has been applied to at least one surface is laminated on both sides of an aromatic polyimide film whose discharge treatment has been applied to both sides, with the discharge treated surfaces facing each other. A polyimide film with fluororesin layers on both sides. 6. The polyimide film having fluororesin layers on both sides as claimed in claim 5, wherein both sides of the fluororesin film are subjected to discharge treatment. 7. The aromatic polyimide film according to claim 5 or 6, wherein the polyimide has a carboxylic acid skeleton derived from biphenyltetracarboxylic dianhydride as the main acid skeleton. Polyimide film with a fluororesin layer.