JP3335304B2 - Method for producing surface-modified polyimide film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface-modified polyimide film and a method for producing the same. The present invention particularly relates to an aromatic compound obtained from an aromatic tetracarboxylic acid component containing 3,4,3 ', 4'-biphenyltetracarboxylic acid or an anhydride or ester thereof and an aromatic diamine component containing p-phenylenediamine. The present invention relates to a polyimide film obtained by dispersing an inorganic filler in a group III polyimide, the surface of which is modified so as to exhibit good adhesiveness.

[0002]

2. Description of the Related Art Aromatic polyimides (wholly aromatic polyimides) produced by polymerization and dehydration of an aromatic tetracarboxylic acid component and an aromatic diamine component have remarkably excellent heat resistance, mechanical strength and the like. Because of its excellent chemical stability, it is particularly used in severe conditions and requires high reliability in technical fields (eg, electronic materials, various materials used in outer space) ) Use is increasing.

[0003] Aromatic polyimides exhibit excellent properties in many properties as described above. However, since the surface of a molded product such as a film is inactive, the adhesion between aromatic polyimide films or the aromatic polyimide film is not effective. There is a problem that adhesion between the metal foil and the metal foil (eg, copper foil) is not easy. And, in the past, the development of adhesives for increasing the adhesion of the aromatic polyimide film to other materials has also been performed, but the adhesion between those adhesives and the surface of the aromatic polyimide film is also insufficient. Absent.

For this reason, a method of improving the adhesiveness of the surface of the aromatic polyimide film by subjecting the surface of the aromatic polyimide film to a discharge treatment such as a corona discharge treatment or a plasma discharge treatment has been studied and used.

For example, JP-A-63-61030 discloses that the oxygen / carbon ratio on the film surface is increased by 0.01 to 0.1 by corona discharge treatment, and the residual volatile matter content is reduced to 0.45. Polyimide films of up to% by weight are described.

JP-A-1-128242 discloses that an aromatic polyimide film is supported by a discharge electrode,
A method for modifying the surface of an aromatic polyimide film by performing a discharge treatment such as corona discharge is described.

JP-A-3-56541 describes a method for modifying an aromatic polyimide film, which comprises treating an aromatic polyimide film with an organic solvent in advance and then performing a plasma treatment.

[0008] Japanese Patent Application Laid-Open No. 5-1160 discloses an aromatic polyimide film in which a discharge treatment such as a plasma discharge is performed at normal pressure using an application electrode having a specific shape while supporting the aromatic polyimide film with a drum electrode. Are described.

[0009]

SUMMARY OF THE INVENTION The method for modifying the surface of an aromatic polyimide film described in each of the above publications can be effectively applied to various heat-resistant resin films centering on an aromatic polyimide film. Have been. However,
It is clarified as specific facts in each description that an aromatic polyimide film produced using pyromellitic dianhydride as a tetracarboxylic acid component and 4,4-diaminodiphenyl ether as a diamine component, Alternatively, it is an aromatic polyimide film manufactured using these materials and having a trade name of "Kapton". According to the examples described in each gazette, corona discharge treatment or plasma discharge treatment for this kind of aromatic polyimide film Has been shown to be effective in improving its adhesive strength.

However, according to the present inventor's study on the improvement of the surface properties of the aromatic polyimide film, it has been found that aromatic polyimides whose surface properties are not sufficiently improved even by the above-mentioned known corona discharge treatment or plasma treatment. The film was found to be present.

That is, as another kind of aromatic polyimide film, an aromatic tetracarboxylic acid component containing 3,4,3 ′, 4′-biphenyltetracarboxylic acid or an anhydride or ester thereof and an aromatic containing p-phenylenediamine An aromatic polyimide film comprising an aromatic polyimide obtained from a diamine component is known, and the aromatic polyimide film is an aromatic polyimide film produced from the pyromellitic dianhydride and 4,4-diaminodiphenyl ether. Polyimide film, even more excellent heat resistance, and is an aromatic polyimide film with excellent mechanical strength and chemical stability, this kind of aromatic polyimide film, especially excellent chemical stability Although it is presumed to be caused, it is known that it is difficult to further improve the surface characteristics. And, for an aromatic polyimide film produced from an aromatic tetracarboxylic acid component containing 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride and an aromatic diamine component containing p-phenylenediamine, Even if the above-described conventional discharge treatment (particularly normal pressure plasma treatment) is performed, satisfactory modification of the film surface (particularly, improvement in adhesiveness) is not realized.

Accordingly, an object of the present invention is to provide an aromatic tetracarboxylic acid component containing 3,4,3 ', 4'-biphenyltetracarboxylic acid or an anhydride or ester thereof having improved surface properties, particularly adhesion. It is to provide an aromatic polyimide film obtained from an aromatic diamine component containing p-phenylenediamine.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to
Finely divided inorganic filler in an aromatic polyimide obtained from an aromatic tetracarboxylic acid component containing 3 ', 4'-biphenyltetracarboxylic acid or an anhydride or ester thereof and an aromatic diamine component containing p-phenylenediamine While the polyimide film having a thickness of 20 to 125 μm in which a plurality of plasma discharge electrodes arranged in two rows are run in a non-contact manner under an atmosphere of a mixed gas of argon and hydrogen, the plasma A method for producing a surface-modified polyimide film, comprising performing a plasma discharge treatment with a discharge electrode.

The plasma discharge treatment operation according to the present invention comprises argon as a main component, and contains 1 to 100 mol of argon.
It is desirable to carry out the reaction in a gas atmosphere of 0.8 to 1.2 atm with addition of ５5 mol of nitrogen and 1 to 50 mol of hydrogen.

In the plasma discharge treatment of the present invention, the amount of the metal element of the inorganic filler in the element composition on at least one surface of the surface-modified polyimide film is 0.03 to 0.03.
It is desirable to increase the concentration by 0.5 at% and increase the oxygen / carbon ratio on the surface by 0.01 to 0.20. In particular, the amount of the metal element of the inorganic filler in the elemental composition on both surfaces of the surface-modified polyimide film is 0.
It is desirable to perform the plasma discharge treatment so as to increase the atomic ratio by 0.5 to 0.5 atomic% and increase the oxygen / carbon ratio at the surface by 0.01 to 0.20. Alternatively, in the plasma discharge treatment, the amount of the metal element of the inorganic filler in the element composition on both surfaces of the surface-modified polyimide film is increased by 0.5 to 1.5 atomic%, and the oxygen / carbon ratio on those surfaces is increased. It is also desirable to carry out so as to increase by 0.11 to 0.15.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing an aromatic polyimide film having a modified surface according to the present invention will be described in detail with reference to typical embodiments. The structure and production method of the aromatic polyimide of the aromatic polyimide film to be the surface modification treatment of the present invention have already been described in known documents including numerous publications, and the aromatic polyimide used in the present invention is such an aromatic polyimide. It can be manufactured by appropriately selecting from known materials and conditions.

The aromatic tetracarboxylic acid component used in the present invention is a 3,3 ', 4,4'-biphenyltetracarboxylic acid component (that is, 3,3', 4,4'-biphenyltetracarboxylic acid; Anhydrides, such as anhydrides, and esters), and 2,3,3 ′, 4′-biphenyltetracarboxylic acid component (eg, dianhydride) and pyromellitic acid component (eg, dianhydride) )) And other aromatic tetracarboxylic acid components. However, the amount of the aromatic tetracarboxylic acid component used in combination should not exceed 90 mol% of the total amount of the aromatic tetracarboxylic acid component (that is, the 3,3 ′, 4,4′-biphenyltetracarboxylic acid component is 10 to 100%). (Amount in the range of mole%).

The aromatic diamine component used in the present invention is p
-Containing phenylenediamine but 4,4 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-dimethoxy-
Other aromatic diamine components such as diphenyl ether diamines such as 4,4'-diaminodiphenyl ether may be used in combination. However, the aromatic diamine used in combination is
It does not exceed 90 mol% of the total amount of the aromatic diamine component used (that is, p-phenylenediamine is 10 to 10 mol%).
Used in an amount in the range of 100 mol%).

The aromatic polyimide film of the present invention has a thickness in the range of 20 to 125 μm, preferably 50 to 1 μm.
It is in the range of 25 μm and contains fine inorganic fillers. Representative examples of the inorganic filler include silicon dioxide, titanium dioxide, magnesium oxide, calcium carbonate, and talc. The inorganic filler preferably has an average particle size in the range of 0.01 to 5.0 μm. The content of the inorganic filler in the aromatic polyimide film is preferably in the range of 0.02 to 5.0% by weight.

The aromatic polyimide film to be subjected to the plasma discharge treatment (normal pressure plasma treatment, ie, the plasma discharge treatment at 0.8 to 1.2 atm) of the present invention comprises an aromatic carboxylic acid component and an aromatic diamine. The dope solution (polyamic acid solution) produced from the components is cast on a long support, and then heated to form a dry film. Then, the dry film is peeled from the support, and then heated to a high temperature. By completing the dehydration imidization, the compound can be produced.

The inorganic filler may be added at any time before, during, or after the production of the polyamic acid dope, and the inorganic filler is present in a state of being dispersed in the finally obtained aromatic polyimide film. There is no particular limitation on the timing and method of addition as long as the addition is performed.

The present invention relates to an aromatic polyimide film, which is particularly difficult to modify the surface, comprising an aromatic tetracarboxylic acid component containing 3,4,3 ', 4'-biphenyltetracarboxylic acid or an anhydride or ester thereof, and p -By adding a fine particle inorganic filler to an aromatic polyimide obtained from an aromatic diamine component containing phenylenediamine and forming a film, a large number of protrusions formed by the inorganic filler are formed on the film surface. And a method of forming a film surface. As described above, a normal aromatic polyimide film is prepared by casting a polyamic acid dope solution on a long support and heating and drying the polyamic acid film to form a polyamic acid film, and then supporting the polyamic acid film. It is peeled off from the body and manufactured using a method of heating this polyamic acid film to a high temperature, but the resulting polyimide film is heated by casting a dope solution containing an inorganic filler in a dispersed state on a support. On the side that has been in contact with the support in the drying step (generally called side B), the adhesiveness has reached a level sufficient for practical use, but on the opposite side (generally called side A). Poor adhesion.

The plasma discharge treatment of the present invention is particularly effective when performed on the A-side of an aromatic polyimide film containing an inorganic filler. That is, by performing a plasma discharge treatment on the surface A of the aromatic polyimide film containing the inorganic filler, the aromatic polyimide layer covering the inorganic filler on the surface is oxidized, destroyed, removed, and the like. Is exposed, and an effective increase in adhesive strength is realized.

Therefore, the plasma discharge treatment of the present invention is preferably performed on the surface A (non-support side surface) of the aromatic polyimide film containing the inorganic filler, but the plasma discharge treatment is, of course, performed on both surfaces of the aromatic polyimide film. Is preferably applied.

Next, the plasma discharge treatment of the aromatic polyimide film containing the inorganic filler of the present invention will be described. The plasma processing in the present invention is desirably performed using a plasma processing apparatus schematically shown in FIG. 1 of the accompanying drawings.

In FIG. 1, reference numeral 11 denotes a housing of a plasma processing apparatus, in which a plurality of plasma discharge chambers 12 are provided. Plasma discharge chamber 12
, A plurality of plasma discharge electrodes 13 are arranged in two rows. The plasma discharge chamber 12 is provided with a mixed gas introduction pipe 15 connected to a mixed gas supply source 14 for supplying a mixed gas of argon and hydrogen forming a discharge atmosphere in the discharge chamber. An inlet 16 and an outlet 17 for an aromatic polyimide film to be plasma-treated are provided.

The gaseous atmosphere for carrying out the plasma discharge treatment of the present invention is mainly composed of argon, and 1 to 5 mol of nitrogen and 1 mol per 100 mol of argon.
A gas atmosphere to which about 50 mol of hydrogen has been added is preferred. If necessary, another inert gas such as helium (preferably 1 to 50 mol) may be added to the gas atmosphere.

Outside and inside the plasma processing apparatus,
A number of film transport rollers 18 are provided for assisting the running of the aromatic polyimide film, and assist the smooth running of the aromatic polyimide film 20 unwound from the film unwinding roll 19, and provide the processed aromatic polyimide film. It works to finally deliver the polyimide film 20 to the take-up roll 21.

The outline of the plasma processing apparatus used for the plasma discharge processing of the present invention is as shown in FIG. 1. For example, the number of discharge chambers is increased / decreased, the arrangement is changed, the number of plasma discharge electrodes is increased / decreased, and the arrangement is changed. Of course, changes can be made.

The plasma discharge process of the present invention is performed, for example, by referring to FIG.
By using the plasma processing apparatus shown in the above, the aromatic polyimide film containing the inorganic filler in a dispersed state is continuously run in the direction of the arrow without contacting the plasma discharge electrode during the discharge, thereby forming a film. In order to realize a discharge treatment on both surfaces, it is preferable to use such a treatment device.

When performing the plasma discharge treatment of the aromatic filler-containing aromatic polyimide film of the present invention, a pretreatment using an organic solvent as described in JP-A-3-56541 is required. Can also.

[0032]

EXAMPLES (1) Aromatic polyimide film Using a long support, a known method was carried out using 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and an equimolar amount of p-phenylenediamine. A long aromatic polyimide film having a thickness of 75 μm (containing 0.2% by weight of SiO ₂ ) was obtained.

(2) Plasma discharge treatment An atmospheric pressure plasma treatment device having the same configuration as the plasma treatment device shown in FIG. 1 (however, only one plasma discharge chamber is provided.
The plasma treatment was performed at 1 atm), and the plasma treatment was performed at the gas composition and the film traveling speed in the plasma discharge treatment chamber shown in Table 1 below.

[0034]

Table 1 Table 1 Plasma treatment gas composition (molar ratio) ) Film running speed ──────────────────────────────────── Comparative example Argon (Ar) only 0.5m / Min Example 1 Ar / N ₂ / H ₂ (90/2/3) 1.0 m / min Example 2 Ar / N ₂ / H ₂ (90/2/3) 0.5 m / min Example 3 Ar / N ₂ / H ₂ (90 / 2.5 / 3) 0.5 m / min Example 4 Ar / N ₂ / H ₂ (90/4/3) 1.0 m / min Example 5 Ar / N ₂ / H ₂ (90/2/3) 1.5 m / min Example 6 Ar / N ₂ / H ₂ (90/2/2) 0.5 m / min Example 7 Ar / N ₂ / H ₂ / He (90 / 2/3/10) 0.5 m / min Example 8 Ar / N ₂ / H ₂ (90/2/5) 0.5m / min ────────────────────────────────────

(3) Surface Composition Analysis of Plasma Discharge Treated Film 1) Measurement of Silicon (Si) Atomic Concentration (Atom%) The silicon concentration on the surface of the aromatic polyimide film subjected to the plasma discharge treatment was measured by using the ESCA method. It was measured. Table 2 shows the results. 2) Increase in oxygen / carbon ratio The oxygen / carbon ratio of each surface of the aromatic polyimide film subjected to the plasma discharge treatment and the aromatic polyimide film not subjected to the plasma discharge treatment was measured by the ESCA method. The results are shown in Table 2 as an increase in the oxygen / carbon ratio with respect to the aromatic polyimide film not subjected to the plasma discharge treatment.

(4) Evaluation of Adhesiveness of Aromatic Polyimide Film Each surface of the aromatic polyimide film subjected to the plasma discharge treatment and the aromatic polyimide film not subjected to the plasma discharge treatment (the surface of the aromatic polyimide film which is in contact with the surface of the support during film production) A side, which is the surface on the side where the film has not been made, and B, which is the surface on the side which came into contact with the surface of the support during film production
Both sides were evaluated for adhesion under the following conditions. A) Adhesive: Acrylic resin adhesive (Pilalux manufactured by DuPont) b) Adhered sheet: copper foil (thickness: 30 μm) c) Adhesion operation: 180 ° C., 20 kg / cm ² , thermocompression bonding for 40 minutes ) Adhesion strength measurement: T peeling, peeling speed 50 mm / min

Table 2 shows the adhesive strengths of the surfaces A and B measured under the above conditions. Table 2 also shows the adhesive strength of the aromatic polyimide film that has not been subjected to the plasma discharge treatment on the A side and the B side.

[0038]

[Table 2] Table 2 Oxygen / carbon Si atom bond strength (Kg / cm) Ratio increase concentration (atomic%) A surface B surface ───────────────────────────────── Untreated film --- 0.16 0.4 1.2 Comparative example 1 --- 0.18 0.5 1.3 ─────────────────── Example 1 0.186 0.23 1.2 1.2 Example 2 0.137 1.08 1.3 1.3 Implementation Example 3 0.144 0.96 1.2 1.3 Example 4 0.127 0.51 1.3 1.4 Example 5 0.115 0.54 1.4 1.4 Example 6 0.120 0.80 1.4 1.4 Example 7 0.119 0.76 1.4 1 0.4 Example 8 0.030 0.25 1.2 1.2 ─── Note: The oxygen / carbon ratio increase and the Si atom concentration are all measured values of the A-plane. In addition, the measured value of the B side of each film was the same as the measured value of the A side.

As is clear from the results shown in Table 2,
3,3 ′, 4,4′-biphenyltetracarboxylic acid in which the oxygen / carbon ratio on the film surface is increased in a certain range and the Si atom concentration is also increased in a certain range by performing the plasma discharge treatment of the present invention. An aromatic polyimide film obtained from dianhydride and p-phenylenediamine shows high adhesiveness. Particularly, on the surface A, which is the surface that was not in contact with the support surface during the production of the aromatic polyimide, the improvement in the adhesiveness is extremely remarkable.

[0040]

The aromatic tetracarboxylic acid component mainly containing 3,4,3 ', 4'-biphenyltetracarboxylic acid or its anhydride or ester and the aromatic diamine component mainly containing p-phenylenediamine In the aromatic polyimide film obtained from the above, the amount of the metal element of the inorganic filler in the element composition on the film surface is determined by dispersing the inorganic filler in the form of fine particles in the film and subjecting the film to plasma discharge treatment. , And the oxygen / carbon ratio on the surface thereof is increased to a certain range, whereby high adhesiveness is exhibited.

[Brief description of the drawings]

FIG. 1 shows an example of a plasma processing apparatus used for performing plasma discharge processing on an aromatic polyimide film in the present invention.

DESCRIPTION OF SYMBOLS 11 Housing of plasma processing apparatus 12 Plasma discharge chamber 13 Plasma discharge electrode 14 Mixed gas supply source 15 Mixed gas introduction pipe 16 Aromatic polyimide film inlet 17 Aromatic polyimide film outlet 18 Film transport roller 19 Film unwinding roll 20 Aromatic polyimide film 21 Film take-up roll

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-143688 (JP, A) JP-A-8-120098 (JP, A) JP-A-5-222219 (JP, A) JP-A-5-222 28458 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J ^7/ 00-7/18

Claims (5)

(57) [Claims] 1. Aroma obtained from an aromatic tetracarboxylic acid component containing 3,4,3 ′, 4′-biphenyltetracarboxylic acid or an anhydride or ester thereof and an aromatic diamine component containing p-phenylenediamine. Non-contact between a plurality of plasma discharge electrodes arranged in two rows under an atmosphere of a mixed gas of argon and hydrogen in a polyimide film having a thickness of 20 to 125 μm in which fine-particle inorganic fillers are dispersed in group III polyimide A method for producing a surface-modified polyimide film, characterized in that a plasma discharge treatment is performed by these plasma discharge electrodes while traveling down. 2. A plasma discharge treatment comprising argon as a main component, and 1 to 5 moles of nitrogen and 1 to 50 moles of hydrogen added to 100 moles of argon.
The method for producing a polyimide film according to claim 1, wherein the method is performed in a gas atmosphere of 2 atm. 3. The amount of the metal element of the inorganic filler in the element composition on at least one surface of the surface-modified polyimide film is 0.03 to 0.03 due to the plasma discharge treatment.
The method for producing a polyimide film according to claim 1 or 2, wherein the plasma discharge treatment is performed such that the atomic ratio increases by 0.5 atomic% and the oxygen / carbon ratio on the surface increases by 0.01 to 0.20. 4. The amount of the metal element of the inorganic filler in the element composition on both surfaces of the surface-modified polyimide film is increased by 0.05 to 0.5 atomic% by the plasma discharge treatment.
And the oxygen / carbon ratio on their surface is 0.01 to
The method for producing a polyimide film according to claim 3, wherein plasma discharge treatment is performed so as to increase by 0.20. 5. The amount of the metal element of the inorganic filler in the element composition on both surfaces of the surface-modified polyimide film is increased by 0.5 to 1.5 atomic% by the plasma discharge treatment, and the oxygen / carbon on those surfaces is increased. When the ratio is 0.11-0.
The method for producing a polyimide film according to claim 1, wherein the plasma discharge treatment is performed so as to increase by 15 times.