JPS63172741A - Aromatic polyimide film and its production - Google Patents

Abstract

PURPOSE:To obtain the title film in which a metal oxide is uniformly dispersed in a state of fine particles and which is excellent in mechanical strengths and dimensional stability, by casting or applying a composition formed by adding a metal oxide sol to a varnish of, e.g., an aromatic polyimide on or to a base and heating it. CONSTITUTION:A composition is obtained by adding 1-100pts.wt. (in terms of the metal oxide) metal oxide sol such as silica sol, alumina sol, iron oxide sol or titania sol and, optionally, 5wt.% or below silane coupling agent (e.g., methyltrimethoxysilane) to 100pts.wt. (in terms of component (a)) aromatic polyimide (a) having repeating units of formula I (wherein Ar<1> is a group of any one of formulas II-IV, Ar2 is a group of any one of formulas V-VII, R is a 1-3C alkyl, alkoxy or a halogen, X is O, S, SO2, a 1-13C alkylene or a group of formula VIII and m and n are each 0-2) or a varnish (b) of a polyamic acid as a precursor of component (a). This composition is cast on or applied to a base such as glass and either dried at 60-170 deg.C for 30-120min or heated at 200-400 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an aromatic polyimide film in which a metal compound is blended and uniformly dispersed, and a method for producing the same.

[Prior Art] Aromatic polyimide resin films made of aromatic tetracarboxylic dianhydride and aromatic diamine have excellent heat resistance and high elastic modulus, so they are used for electrical circuits such as flexible printed wiring boards. Widely used for board applications.

However, organic materials generally have the disadvantage of having a higher coefficient of thermal expansion than inorganic materials, and polyimide films are no exception to this.Therefore, for example, polyimide films and metal foils are bonded together by heat. In some cases, an adhesive layer with low heat resistance is required to prevent curling caused by stress caused by differences in thermal expansion coefficients, and the heat resistance of polyimide film cannot be fully utilized. Its use was restricted.

Under the current situation as described above, attempts have recently been made to improve the coefficient of thermal expansion of polyimide films and to reduce the difference in coefficient of thermal expansion with inorganic materials.

For example, polyimide containing a unit structure of the following formula (where Ar3 is an aromatic group; R' is a lower alkyl group, acyl group, or halogen; n is an integer from 0, 1 to 4) has low expansion. An attempt to improve the efficiency is disclosed in Japanese Unexamined Patent Publication No. 130-250031.

[Problems to be Solved by the Invention] One of the above-mentioned attempts at improvement is to lower the expansion coefficient by, for example, changing the structure of the diamine constituting the polyimide unit. However, on the other hand, it is difficult to synthesize the monomer, and therefore the obtained heptamer is expensive and extremely difficult to obtain, making it unsuitable for general use. Moreover, there are many unclear points regarding the toxicity of Nanatsuma, and the precautions for handling it are also completely unknown.

In view of the above-mentioned problems, the present inventors conducted various research on polyimide films that have low thermal expansion and improved dimensional stability without sacrificing heat resistance, strength, etc., based on polyimide that is easily available at present. We have considered this. As a result, they discovered that a polyimide film that satisfies the above conditions can be obtained by blending a metal oxide into polyimide and uniformly dispersing it, and in particular by adopting specific means, and have completed the present invention. This is what happened.

Therefore, an object of the present invention is to provide an aromatic polyimide film having excellent heat resistance, strength, dimensional stability, etc., which is made by dispersing metal oxides uniformly in easily available polyimide, and a method for producing the same. It is something.

[Means for Solving the Problems] That is, one of the present inventions is an aromatic polyimide film in which a metal oxide is blended with polyimide, wherein the aromatic polyimide film is derived from a metal oxide sol. The present invention provides an aromatic polyimide film characterized by being made of an aromatic polyimide containing a metal oxide.

Another aspect of the present invention is a composition in which a metal oxide sol is blended with an aromatic polyimide varnish or a polyamic acid varnish, which is a precursor of aromatic polyimide, in a method for producing an aromatic polyimide film. The present invention provides a method for producing an aromatic polyimide film, which comprises casting or coating the film onto a substrate and then heating the film to obtain a film made of aromatic polyimide containing a metal oxide.

In the present invention, the aromatic polyimide is not particularly limited, but as described above, as a polyimide consisting of an easily available diamine and an acid anhydride, aromatic polyimides of the general formula CI) are represented by L
; X represents a fullkylene group having 1 to 13 carbon atoms; Preferably, it is an aromatic polyimide having Such polyimide is one or two types.
You may use more than one species in combination.

In the aromatic polyimide film of the present invention, the metal oxide contained in the aromatic polyimide is a metal oxide derived from a metal oxide sol. Examples of such metal oxide sols include silica sol, alumina sol, antimony oxide sol, iron oxide sol, zirconia sol, titania sol, and tin oxide sol. Particularly preferred are silica sol, alumina sol, zirconia sol, and titania sol. Alternatively, a mixture of two or more types may be used.

It is a well-known method to improve mechanical strength and heat resistance by adding inorganic fillers to organic shredded oil.
When such a method is applied to a film, the properties of the obtained film such as surface smoothness and strength tend to deteriorate significantly.

For example, a method of mechanically mixing inorganic powder into a polyarylene polyether polyimide film was published in 1980.
Although disclosed in Japanese Patent No. 228557, it is preferable that the amount of inorganic powder is 10% or less based on the resin;
It has been revealed that if it exceeds 10%, problems will occur in terms of surface smoothness and strength. In other words, even if 10% or more is blended, the powder, which normally exists as secondary particles, is not completely converted into primary particles, and the particles themselves become defects in the film, resulting in a decrease in the strength of the film. , which has the disadvantage of becoming brittle. In fact, the results of studies conducted on polyimide films by the present inventors show that the films obtained by mechanically distributing metal oxide fine powder on polyamic acid varnish and imidizing the film have flexibility. In particular, when the amount of metal oxide was large, it was difficult to obtain a self-supporting film.

Therefore, in the present invention, it is extremely important that the metal oxide is blended into the aromatic polyimide in the form of a metal oxide sol. There is a 4'F characteristic in blending a metal oxide sol with a varnish or a varnish of polyamic acid, which is a precursor of aromatic polyimide, and forming it into a film by casting.

In the method for producing an aromatic polyimide film of the present invention, a solvent-soluble polyimide is used as the aromatic polyimide varnish, and the polyimide is, for example, phenol, 0-cresol, m-cresol, p-cresol, m phenols such as 3,5-xylenol, N-
It is used in the form of a solution dissolved in an organic solvent such as methyl-2-pyrrolidone or N-N'-dimethylformamide. In addition, as a varnish of polyamic acid, which is a precursor of aromatic polyimide, polyamic acid can be used, for example.
N-methyl-2-pyrrolidone.

Those synthesized by known methods in a polar solvent such as N-N'-dimethylformamide, N-N'-dimethylacetamide, and dimethyl sulfoxide are used. As an aromatic polyimide varnish, the concentration of polyimide is not particularly limited depending on the viscosity of the polymer, but is usually 5 to 30%.
The concentration of polyamic acid is preferably 5% to 30% by weight, and the concentration of polyamic acid is not particularly limited depending on the viscosity of the polymer, but it is preferably 5 to 30% by weight. Concentration 0
．． It is preferable that the logarithmic viscosity in 2g/100+5lN-methyl-2-pyrrolidone is 0.2 or more, particularly 0.5 or more.

The metal oxide sol used in the present invention includes the above-mentioned sols, and is usually available in the form of an aqueous sol or an alcoholic sol, with alcoholic sol being particularly preferred. An aqueous sol or an alcoholic sol of a metal oxide is prepared by adding a solvent that does not precipitate polyimide and polyamic acid, and then distilling off some or all of the water or alcohol to obtain an organic sol of a metal oxide sol. Prepare as The solvent used for these is N
-Methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide 4-o-lactone, cresol, phenol, halogenated phenol, etc. The average particle size of the organic sol obtained by the above method is usually 3 μm or less, and particularly preferably 1 μm or less. In the organic sol, the solid content concentration of the sol is preferably 1 to 50% by weight, particularly preferably 5 to 30% by weight, from the viewpoint of sol stability.

In a composition in which an organic sol of metal oxide sol is blended with pheno of aromatic polyimide or pheno of polyamic acid, the blending ratio of the organic sol is as follows: The amount of metal oxide derived from the metal oxide sol is 1 to 100 parts by weight, preferably 10 to 50 parts by weight, particularly preferably 1 to 100 parts by weight of the aromatic polyimide component.
It is blended in an amount of 5 to 30 parts by weight. In the above-mentioned composition, the total concentration of solid components in the composition depends on the viscosity, which affects workability when forming a cast film by casting or coating on a substrate, or the desired thickness of the resulting film. Although it is determined as appropriate, it is preferably 5 to 40% by weight.

In formulating the composition as described above, in order to improve the compatibility between the aromatic polyimide component and the metal oxide component and obtain uniform dispersibility, a silancan coupling agent is blended at a ratio of 5% by weight or less. It's okay. It is particularly effective to incorporate at least 2% by weight. Therefore, the silane coupling agent not only acts as a dispersion improver and dispersion stabilizer for the polyimide component and sol particles, but also acts as a dispersion stabilizer and dispersion improver for the polyimide component and sol particles. It can be combined with other groups, and the physical properties of the resulting film can be significantly improved. Examples of usable silane coupling agents include alkyl silane coupling agents such as methyltrimethoxysilane, halogen silane coupling agents such as γ-chloropropyltritomexysilane, and vinyl silane coupling agents such as vinyltriethoxysilane. ring agents, methacrylic silane coupling agents such as γ-methacryloxypropyltrimethoxysilane, epoxy silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, and mercapto-based silane coupling agents such as γ-mercaptopropyltriethoxysilane. silane cuff pulling agent,
Hydroxy-based silane coupling agents such as (jetanolamine)propyltriethoxysilane, incyanate-based silane coupling agents such as γ-incyanatopropyltrimethoxylane, and amine-based silanes such as γ-aminopropyltrimethoxysilane. Examples include coupling agents and their salt types, and such silane coupling agents may be used alone or in combination of two or more types. The silane coupling agent may be simply mixed during film formation or when blending the metal oxide sol, but the polyimide component has a functional group and some interaction or bond formation with the silane coupling agent is expected. If the polyimide component is used, the polyimide component may be mixed with the polyimide component in advance, or pretreatment such as heating may be performed.

In the method for producing the film of the present invention, the cast film forming method by casting or applying the composition onto a substrate and then heating is not particularly limited, and any known method may be employed. 0 For example, after applying it uniformly to a glass plate as a substrate using an applicator,
After drying at a temperature of 30 to 120 minutes, the formed film is peeled off to obtain a self-supporting film. In the case of a composition made of polyamic acid, the metal oxide is imidized by fixing the self-supporting film obtained by the above method to an iron frame and heat-treating it at 200 to 400°C. An aromatic borimide film made of aromatic polyimide containing a metal oxide derived from a sol can be obtained.

[Example] The present invention will be explained in more detail with reference to Examples.
First, the preparation of an organic sol regarding the metal oxide sol will be explained.

Preparation Example 1 Preparation of Silica Sol 100 g of tomethyl-2-pyrrolidone was charged into a reactor equipped with a stirrer, a dropping funnel, and a reflux condenser.
While vigorously stirring, 83 g of 30% silica isopropyl alcohol sol ("03CAL-1432", manufactured by Catalysts & Chemicals Co., Ltd.) was added dropwise from the dropping funnel at room temperature over 10 minutes. Next, the attached reflux condenser was replaced with a distillation device, and the reactor was heated in an oil bath to 100-130℃.
58 g of isopropyl alcohol was distilled off and cooled to give a transparent and uniform N-methyl-2-2-
Pyrrolidone sol was obtained. The average particle diameter of this sol was 120 when measured at 25°C using a Coulter Counter ("N-4°", manufactured by Coulter Inc.).

Preparation Example 2 Preparation of silica-titania mixed sol Instead of the silica sol in Preparation Example 1, titanium oxide 10
% aqueous solution sol (manufactured by Tamoto Chemical Co., Ltd.) 100g and silica 30
% methanol sol (“03CAL-1132” manufactured by Catalysts Kasei Kogyo Co., Ltd.) in the same manner as in Preparation Example 1.
125 g of water-methanol was distilled off by heating,
After cooling, a silica-titania 20% N-methyl-2-pyrrolidone sol was obtained. The average particle size of this sol is 180
It was a person.

Examples 1 to 8 A reactor equipped with a stirrer, a dropping funnel, a reflux condenser, and a nitrogen gas introduction tube was charged with diamines and aminosilanes shown in Table 1, and the solid concentration of polyamic acid was 20.
N-methyl-2-pyrrolidone was added in an amount of % by weight and stirred until homogeneous.Next, while cooling this solution to 5°C in a water bath, the tetracarboxylic dianhydride shown in Table 1 was added. and the tetracarboxylic dianhydride was dissolved with stirring. After dissolution, the water bath was removed and the mixture was reacted at room temperature for about 5 hours to obtain a polyamic varnish having the logarithmic viscosity shown in Table 1.

The organic sol of the metal oxide obtained in Preparation Example 1 was added to 100 parts by weight of the solid content in the obtained polyamic acid varnish as shown in Table 1 to prepare a mixed varnish of polyamic acid-metal oxide sol. was prepared.

The mixed varnish of polyamic acid-metal oxide sol thus prepared was applied uniformly onto a glass plate using an applicator, and dried by holding at 50 to 60°C for 60 minutes and then at 170°C for 60 minutes. Afterwards, the film formed from the glass plate was peeled off. The film was fixed in a steel frame and heated to 320°C for 120 minutes, then to 400°C for 120 minutes.
After cooling, a film having a thickness of 50 mm and made of aromatic polyimide containing a metal oxide uniformly dispersed therein was obtained.

The physical properties of the obtained film were measured as follows.

[Tensile strength, tensile modulus]: ASTM-D-88
Measured at 23°C according to the method shown in 2-80.

[Flexibility]: AS TM-D-2178-83T
(MIT method) at 23°C.

[Coefficient of linear expansion]: TMA method (DT-4 manufactured by Takasugi Seisakusho)
0), and the average value of the slope at 50 to 250°C was taken as the linear expansion coefficient.

Table 1 shows the results of measuring film properties using the above method.

Comparative Examples 1 to 3 A transparent film with a thickness of 50 JL made of aromatic polyimide was prepared in the same manner as in Examples 1 to 8, except that the organic sol of metal oxide was not added to the polyamic acid varnish in Examples 1 to 8. I got it.

The properties of the obtained film were measured in the same manner as in Examples 1-8. The results are shown in Table 2.

Comparative Examples 4 to 6 Fine particles of metal oxide were directly added to the polyamic acid varnish shown in Table 2 without using an organic sol of metal oxide, and the total solid concentration was adjusted to 20% by weight. After that, the mixture was vigorously stirred and mixed using a mixer to obtain a translucent viscous varnish.

The varnish thus obtained was formed into a film in the same manner as in Examples 1-8.

The properties of the obtained films were measured in the same manner as in Examples 1 to 8, but in Comparative Examples 5 and 6, many cracks occurred during film formation, and no films were obtained.

Explanation of abbreviations in Table 1.2 DADE: 4,4-diaminodiphenyl ether γ-A
PTS: 3-Aminopropyltriethoxysilane ρ-PDA: Halaphenylenediamine BAPS: Pis(4-(4-aminophenoxy)phenyl)sulfone PDA: Pyromellitic dianhydride PDA: 3,3'・4 , 4'-biphenyltetracarboxylic a) A: Using the organic sol of Preparation Example 1 B: Using the organic sol of Preparation Example 2 C: a Fine particulate anhydrous silica (using Nippon Aerosil Co., Ltd. 5i DJ fine particulate anhydrous titanium) (manufactured by Nippon Aerosil Co., Ltd.) Use E: Use of talc could not be made into a film [Effects of the invention] When preparing a composition in which a metal oxide is blended with an aromatic polyimide polymer, the present invention uses a sol-like metal oxide. It is characterized by its skillful use, and circulation is the uniform dispersion of metal oxides in the form of fine particles by such means.

This composition is formed into a film by forming a film, and the resulting film is recognized to be superior in mechanical strength, thermal expansion coefficient, and other dimensional stability as compared to a simple polymer film.

Claims (4)

[Claims] (1) An aromatic polyimide film made of polyimide mixed with a metal oxide, characterized in that the aromatic polyimide film is made of an aromatic polyimide containing a metal oxide derived from a metal oxide sol. Aromatic polyimide film. (2) Aromatic polyimide has the general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (However, Ar^1 in the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲mathematical formulas, chemical formulas) , there are tables, etc. ▼, ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼; Ar^2 is selected from ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ there are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ mathematical formulas, Selected from chemical formulas, tables, etc.▼, ▲numerical formulas, chemical formulas, tables, etc.▼; R represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a halogen; X is -O-, -S-, -SO_2-, ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ indicates an alkylene group having 1 to 13 carbon atoms; m and n each indicate an integer of 0 to 2.) Aromatic having a repeating unit represented by The aromatic polyimide film according to claim 1, which is polyimide. (3) The aromatic polyimide containing a metal oxide contains 1 to 1 part of the metal oxide component per 100 parts by weight of the aromatic polyimide component.
2. The aromatic polyimide film according to claim 1, wherein the aromatic polyimide film contains 0.00 parts by weight. (4) In the method of manufacturing an aromatic polyimide film, a composition obtained by blending a metal oxide sol with an aromatic polyimide varnish or a polyamic acid varnish, which is a precursor of aromatic polyimide, is cast or applied onto a substrate. 1. A method for producing an aromatic polyimide film, which comprises heating the aromatic polyimide film after heating to obtain a film made of aromatic polyimide containing a metal oxide.