JPH0518865B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a film made of a polyimide resin, and more particularly to a film made of a polyimide resin composition in which a polyimide polymer contains a specific amount of a polysulfone polymer. Polyimide resins have excellent mechanical, physical, chemical, and electrical properties over a wide temperature range from low to high temperatures, and therefore have a wide variety of uses. Widely used as molded products, such as coatings for electric wires and cables, coatings for magnet wires, slot runners for motors, interlayer insulation films for transformers, flexible printed circuit boards, capacitor films, base films for magnetic recording, heat-resistant adhesive tapes, etc. It is used. Generally, polyimide film is produced by casting a solution of polyimide in an organic solvent or a solution of polyamic acid, which is a precursor of polyimide, onto a heated drum (belt), drying and removing the solvent with hot air, and then removing the film from the heated drum (belt). A polyimide film is obtained by peeling off the film and subjecting it to heat treatment. However, since the film obtained by this method has an extremely smooth surface, it has extremely poor slip properties, and there are major problems in winding and unwinding the film and in its subsequent processing. Possible ways to improve slipperiness include roughening the surface of the heating drum (belt) or adding inorganic particles, but these methods may improve slipperiness, but they also result in the surface becoming extremely rough. However, it was difficult to form uniform irregularities, and the resulting film was of significantly inferior commercial value. That is, with the prior art, it has been difficult to obtain a film with a smooth surface and good sliding properties. In order to solve the above-mentioned problems, the present inventors conducted extensive research and unexpectedly found that by incorporating a specific amount of polysulfone-based polymer into polyimide resin, it was possible to create a film using conventional casting film technology. too,
The inventors have discovered that a polyimide film with a smooth surface and good slip properties can be obtained, leading to the completion of the present invention. That is, the gist of the present invention is that the general formula (In the formula, R ¹ is

[expression] or

[Formula] (X is a single bond, -O -,

[Formula] _-CH2- , -C( _CF3 ) ₂ , or -C( _CF3 ) _2- ), ^R2 is an aromatic diamine residue, and n represents a positive integer. ) is soluble in an organic solvent and has at least one sulfone group in the repeating unit _-SO2 A polyimide film comprising a polyimide resin composition containing 0.01 to 5 parts by weight of an aromatic polysulfone polymer having -. The polyimide polymer referred to in the present invention can be obtained, for example, by a known reaction between a diamine compound and a tetracarboxylic dianhydride. That is, 4,4'-diaminodiphenyl ether,
Diamine compounds such as 4,4'-diaminodiphenylmethane, p-phenylenediamine, 3,3'-dimethylbenzidine, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, 3,
A tetracarboxylic dianhydride such as 3',4,4'-biphenyltetracarboxylic dianhydride is charged in substantially equimolar amounts, and N,N'-dimethylformamide,
A polyimide precursor solution is prepared by reacting in an organic solvent such as N,N-dimethylacetamide, N-methyl-pyrrolidone, phenol, p-chlorophenol, etc. at a relatively low temperature, e.g., 50°C or less. It is produced by a known method such as imide ring closure. Also, for example, 3, 3', 4,
It can also be produced by reacting a mixture of 4'-benzophenonetetracarboxylic dianhydride, triene diisocyanate and methylene bis(phenylisocyanate) simultaneously or sequentially. Note that a plurality of types of diamine compounds may be used, or a small amount of a triamine compound may be used in combination. Moreover, multiple types of tetracarboxylic dianhydrides can be used as necessary. Examples of R ¹ in the repeating unit of the polyimide polymer of the general formula [] include groups of the following structural formula.

【formula】

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【formula】

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【formula】

[Formula] Also, in the repeating unit of the polyimide polymer,
Examples of R ² include groups of the following structural formula.

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

Furthermore, n of the repeating unit of the polyimide polymer
It is preferably 10 or more and 1000 or less in view of the heat resistance, mechanical strength, etc. of the polyimide polymer. or,
In N,N-dimethylformamide or 97% concentrated sulfuric acid
Preferably, the concentration is 0.5 g/dl and the logarithmic viscosity (ηinh) measured at a temperature of 30° C. is in the range of 0.5 dl/g to 10 dl/g. The aromatic polysulfone polymer referred to in the present invention is produced by polycondensation of sodium salt of bisphenol A and 4,4'-dichlorodiphenylsulfone, polycondensation of potassium salt of 4-(4-chlorophenylsulfonyl)phenol, etc. It is an aromatic polysulfone-based polymer that is soluble in the organic solvent described below and has at least one sulfone group _-SO2- in the repeating unit, as represented by the polysulfone described below. Examples include known polysulfone polymers having repeating units such as. Here n is a positive integer,
Those having a molecular weight of 5 or more and 1000 or less are preferable in terms of heat resistance, mechanical strength, or solubility in organic solvents. Organic solvents for polysulfone polymers are not particularly limited, but include, for example, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylformamide.
-Amides such as dimethylpropionamide, N-
Methyl-2-pyrrolidone, 1,5-dimethyl-2
- Pyrrolidones such as pyrrolidone, phenol, p
Examples include phenols such as -chlorophenol and o-chlorophenol, organic halogen compounds such as trichloroethane, trichloromethane, and tetrachloroethane, and dimethyl sulfoxide. The amount of the polysulfone polymer added is 0.01 to 5 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the polyimide resin. If the amount is less than 0.01 part by weight, the slipperiness will not be sufficiently improved, and if it is more than 5 parts by weight, the slipperiness will be sufficiently improved, but the surface will become rough and only products with significantly inferior commercial value will be obtained. Next, a method for producing the polyimide resin composition of the present invention will be explained. After adding and mixing the polysulfone polymer or its organic solvent solution to the polyimide precursor solution or polyimide solution, the organic solvent is removed by drying.
Heat and dry as necessary. In the case of a polyimide precursor, the composition of the present invention is obtained by carrying out imide ring closure simultaneously with heating and drying, or by heating and closing imide rings after drying. Note that when the polysulfone polymer is added in solid form rather than in solution form, it is preferable to use a solvent that dissolves the polysulfone polymer as the solvent for the polyimide or its precursor solution. In addition, during the production of a polyimide precursor or polyimide, that is, during polymerization, a polysulfone polymer or its organic solvent solution may be added together with the monomer or during polymerization to produce a polyimide precursor or polyimide containing a polysulfone polymer. After obtaining the solution, the composition of the invention may be obtained as described above. The polyimide resin composition of the present invention is useful as extremely heat-resistant films, coatings, etc., and in particular has improved slipperiness, characterized by a small coefficient of dynamic friction despite having small surface irregularities. . It can be widely applied to electronic and electrical insulating materials. The film or sheet made of the polyimide resin composition of the present invention can be used as a belt (drum) as described above.
It is generally produced by a method of casting on
It can also be produced by casting on a glass plate or the like as shown in the Examples. Also, aluminum,
A laminate can also be produced by coating a substrate of iron, steel, copper, ceramics, etc. and drying and removing the solvent. The composition of the present invention may be blended with known compounding agents such as antioxidants, heat stabilizers, ultraviolet absorbers, colorants, etc. according to methods known per se. The present invention will be explained in detail below with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. The coefficient of dynamic friction is the coefficient of dynamic friction between films measured based on ASTM-D-1844.
It represents the slipperiness of the film, and the smaller the coefficient of dynamic friction, the better the slipperiness. In addition, the surface roughness (Ra) was determined by using an ET-10 type thin film step measuring instrument manufactured by Kosaka Laboratory, and the average protrusion height was determined according to the method defined in JIS-B0601. Examples 1 to 6, Comparative Examples 1 to 4 0.94 kg of 4,4'-diaminodiphenyl ether (hereinafter abbreviated as ODA) and N,N were placed in a 25 polymerization pot.
-Dimethylformamide (hereinafter abbreviated as DMF)
17.73 kg was charged and stirred for 1 hour to completely dissolve ODA. Next, pyromellitic dianhydride (hereinafter
After adding 1.03 kg (abbreviated as PMDA) little by little, the reaction solution was polymerized for 5 hours with stirring while maintaining the temperature at 20°C to obtain a viscous polyimide precursor (polyamic acid) solution. Take a portion of this solution and DMF
A 0.5 g/dl solution was prepared by diluting the solution, and the logarithmic viscosity was measured and found to be 2.5 dl/g. Next, add 200g of this polyimide precursor solution.
A 20% by weight solution of N-methylpyrrolidone (hereinafter abbreviated as NMP) of a polysulfone polymer was added to 100 parts by weight of the polyimide polymer obtained by ring-closing the polyimide precursor. The mixture was added in the proportions shown in Table 1 and stirred at room temperature for 5 hours to mix well. This mixed solution was cast onto a glass plate using a doctor knife and dried in a hot air dryer at 120°C for 10 minutes. Next, this semi-dry film was fixed on a metal frame, and further heated from 120°C to 250°C for 15 minutes, and finally heat treated at 350°C for 4 minutes to obtain a 25 μm film of the resin composition of the present invention. . Table 1 shows the results of measuring the surface roughness and dynamic friction coefficient of this polyimide film.

[Table] Examples 7 to 11 Logarithmic viscosity was measured in the same manner as in Example 1 except that 0.5 kg of 3,3'-dimethylbenzidine (hereinafter abbreviated as OTD), 0.47 kg of ODA, and 1.03 kg of PMDA were used.
A 2.7 dl/g polyimide precursor solution was obtained, and a polysulfone polymer was mixed therein to produce a cast film. Table 2 shows the results of measuring the coefficient of dynamic friction and surface roughness.

【table】

[Table] Example 12 DMF177.3 in a 300ml flask equipped with a stirring device
g and Polyimide 100 is a polysulfone polymer with the structure of
The ingredients were added in an amount of 3 parts by weight and dissolved under stirring. Next, 9.4 g of ODA was charged and dissolved, and then 10.3 g of PMDA was added and reacted at room temperature for 5 hours.
Logarithmic viscosity was 2.6 dl/g. Example 1
When I made a film by casting in the same way,
The coefficient of dynamic friction was 0.8 and Ra was 0.06 μm. Examples 13-15 3,3',4,4'-benzophenonetetracarboxylic dianhydride, toluene diisocyanate and methylene bis(phenyl isocyanate) (mole ratio
80/20) in DMF by a known method to obtain a DMF-soluble polyimide. Logarithmic viscosity is 0.7
It was dl/g. A polysulfone polymer was added in the same manner as in Examples 1 to 6, and a cast film thereof was produced. Table 3 shows the results of the dynamic friction coefficient and surface roughness.

[Table] Example 16 To the polyimide precursor solution containing the polysulfone polymer used in Example 7, 4 moles of isoquinoline as a catalyst and 4 moles of acetic anhydride as a dehydrating agent were added to 1 mole of pyromellitic acid units of the polyimide precursor and mixed well. After that, a polyimide film was produced in the same manner as in Example 1. Its dynamic friction coefficient was 0.7 and Ra was 0.06 μm. Example 17 The polyimide solution containing the polysulfone polymer used in Examples 13 to 15 was coated on a mirror-finished 2 mm thick aluminum plate and heated at 120°C for 10 minutes.
The temperature was raised to 250°C for 15 minutes, and finally heat treated at 300°C for 4 minutes to obtain a polyimide coated aluminum plate.
In all cases, the surface roughness was the same as in Examples 13-15.

Claims (1)

[Claims] 1. General formula (In the formula, R ¹ is [Formula] or [Formula] (X is a single bond, -O -, [Formula] -CH ₂ -, -C(CH ₃ ) ₂ -, or -C(CF ₃ ) ₂ - ), R ² is an aromatic diamine residue, n represents a positive integer), and has a logarithmic viscosity of 0.5 to 10 dl/g.
For 100 parts by weight of thermoplastic aromatic polyimide,
Soluble in organic solvents and containing at least 1 repeating unit
1. A polyimide film comprising a polyimide resin composition containing 0.01 to 5 parts by weight of an aromatic polysulfone polymer having _-SO2- sulfone groups.