JPH0796618B2 - Low thermal expansion resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a low thermal expansion resin made of polyamideimide.

[Prior Art] Most linear expansion coefficients of organic polymers are 4
It shows a value of × 10 ^-5 (K ^-1 ) or more, which is much larger than that of metals and inorganic substances. As described above, there are many problems caused by the large linear expansion coefficient of the organic polymer. For example, when the organic polymer is compounded with a powder or fiber of a metal or an inorganic material, interfacial peeling with the filler occurs due to heat cycle or the like. Or cracks may occur,
Also, when a molded product is formed by using only a resin, the problem of sink marks is large, and it is difficult to perform molding with precise dimensional accuracy.

Further, as a method for manufacturing a flexible printed circuit board (FPC) consisting of a film and a conductor, there has been proposed a method in which a flexible film material is coated on a metal foil at the time of manufacturing, followed by curing and drying with high heat or thermocompression bonding. In this method, when cooled to room temperature, curling occurs due to thermal stress due to the difference in linear expansion coefficient, and when the FPC copper foil is etched, there is a problem that the dimensions change greatly due to strain relief. .

Therefore, in such an FPC, a low-temperature curable adhesive is used for bonding so that these phenomena do not occur. However, since low-temperature curable adhesives generally have poor heat resistance, even if a heat-resistant film such as a polyimide film is used as the base material in the method of bonding with this adhesive, the original heat resistance cannot be exhibited and It becomes difficult to manufacture an excellent FPC,
Moreover, the flame retardance is often lowered due to the adhesive layer.

On the other hand, in the case of a coating film, when this is applied on a metal plate or an inorganic material having a very small linear expansion coefficient as compared with a normal organic polymer, it is deformed by thermal stress due to the difference in the linear expansion coefficient, Film cracking, peeling, substrate destruction, etc. occur. For example, if a coating film is formed on a silicon wafer as a protection film for LSIs and ICs, the wafer may warp and photolithography for patterning may not be possible, or problems such as extremely low resolution may occur, and further passivation may occur. The film may be peeled off or the silicon wafer itself may be cleaved.

As described above, there are many problems due to the large linear expansion coefficient of the organic polymer, and development of an organic polymer having a low thermal expansion coefficient has been demanded.

Therefore, as such a low thermal expansion resin, for example, in JP-A-60-250,031 and JP-A-60-243,120, aromatic tetracarboxylic acid such as biphenyltetracarboxylic dianhydride and o- Although low thermal expansion polyimides obtained by reacting aromatic diamines such as trizine have been proposed, these are in view of physical properties of the resin produced, especially bending resistance and dimensional stability during heating. It is not always satisfactory, and further improvement is required in terms of adhesive strength.

Also, U.S. Pat.Nos. 3,179,635, 3,511,728 and 3,
In each specification of No. 536,545, the repeating unit as shown below (In the formula, R is Is a divalent aromatic group, and R'is Polyamideimide having a tetravalent aromatic group such as) is disclosed.

Although these polyamide-imides have low linear expansion coefficients, they have problems of water absorption and adhesive strength, and when they are used as insulating materials for flexible printed boards, they have poor solder resistance.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a low thermal expansion resin made of a novel polyamide-imide resin having excellent properties in mechanical properties such as bending resistance and adhesiveness. Especially.

Another object of the present invention is to provide a low thermal expansion resin having improved water absorption.

[Means for Solving Problems] That is, the present invention provides the following general formula (I): [In the formula, Ar represents a tetravalent aromatic group, and R is the following general formula (a) and / or (b). (Wherein R1 to R3 represent the same or different alkyl groups, alkoxy groups or halogens, l, m and n are integers of 0 to 4 and have at least one alkoxy group), and x is 5 to 1,000. Is an integer of 3]
Structural unit 0 to 100 mol%, derived from a tetracarboxylic acid and / or a tricarboxylic acid and a diamine containing no structure represented by the above (a) and / or (b) in the molecule
It is a low thermal expansion resin characterized by comprising 70 mol%.

The low thermal expansion resin having the structural unit represented by the general formula (I) is represented by the following general formula (II) [In the formula, Ar represents a tetravalent aromatic group, and R is the following general formula (a) and / or (b). (Wherein R1 to R3 represent the same or different alkyl groups, alkoxy groups or halogens, l, m and n are integers of 0 to 4 and have at least one alkoxy group), and x is 5 to 1,000. It is manufactured by curing a polyamideimide precursor represented by

The polyamideimide precursor represented by the general formula (II) is represented by the following general formula (III) H ₂ N—R—NH ₂ (III) [wherein R represents the following general formula (a) and / or Or (b) (Wherein R1 to R3 represent the same or different alkyl groups, alkoxy groups or halogens, l, m and n are integers of 0 to 4 and have at least one alkoxy group), and x is 5 to 1,000. A diamine represented by the following general formula (IV) (In the formula, Ar is the same as in the case of the general formula (I)) and is obtained by reacting with an aromatic tetracarboxylic acid represented by the following formula or a derivative thereof.

The diamine represented by the general formula (III) and the general formula (I
V) in the aromatic tetracarboxylic acid represented by
A, R1 to R3, l to n and x are Ar, A, R1 to R3 and l in the structural units represented by the general formulas (I) and (II), respectively.
~ N and x.

The above R1, R2 and R3 are an alkyl group, an alkoxy group or a halogen, and the alkyl group and the alkoxy group may be a substituted alkyl group or a substituted alkoxy group, preferably a lower alkyl having 5 or less carbon atoms. Group, a lower alkoxy group having 5 or less carbon atoms or halogen, and more preferable specific examples thereof include methyl group, ethyl group, propyl group, methoxy group, ethoxy group, propoxy group, fluorine,
Examples thereof include chlorine and bromine. These substituents
R1, R2 and R3 may be the same or different from each other, but at least one of them must be an alkoxy group. Further, the above l, m and n are integers of 0 to 4 and have at least one alkoxy group, so the total of these l + m + n is 1 or more, preferably 1 or 2.

Further, the alkoxy group is preferably a lower alkoxy group having 3 or less carbon atoms, more preferably a methoxy group. And regarding the substitution position of this alkoxy group,
The ortho position of the benzene ring adjacent to the amide bond is preferable, and the ortho position of any one of the benzene rings adjacent to the nitrogen atom of the amide bond is more preferable. By introducing an alkoxy group into the structural unit, the adhesive strength of the resin material is improved and its water absorption is lowered, which causes swelling or peeling between the conductor and the insulating material during soldering. No need for pre-drying when soldering.

Further, x is 0 or 1, but is preferably 0.
When x is 0, it is most preferred that either one of R1 or R2 is a methoxy group and the sum of l and m is 1. In the benzene ring between the amide bond and the nitrogen atom of the imide bond in the structural unit, it is more advantageous that the alkoxy group is in the ortho position of the amide bond and the imide bond is in the para position of the amide bond.

Also, the above Ar is A tetravalent aromatic group such as or a derivative thereof such as an alkyl-substituted derivative thereof is preferable. Further, the number of repeating structural units in the general formulas (I) and (II) is an integer of 1 or more, preferably 5 to 1,000.
Is an integer.

And as a preferable specific example of the diamine represented by the above general formula (III), for example, x = 0, for example, 2-methoxy-4,4'-diaminobenzanilide, 2'-methoxy-4,4'- Diaminobenzanilide, 2'-methoxy-4,5'-diaminobenzanilide, 2-ethoxy-
4,4'-diaminobenzanilide, 2'-ethoxy-4,
4'-diaminobenzanilide, 2-propoxy-3,4 '
-Diaminobenzanilide, 2'-propoxy-4,4 '
-Diaminobenzanilide, 2,2'-dimethoxy-4,4 '
-Diaminobenzanilide, 2-methoxy-2'-ethoxy-4,3'-diaminobenzanilide, 2,6-dimethoxy-4,4'-diaminobenzanilide, 2,2'-dimethoxy-3,4'- Diaminobenzanilide, 2,2'-diethoxy-4,4'-diaminobenzanilide, 2,6-diethoxy-4,4'-diaminobenzanilide and the like can be mentioned, preferably 2-methoxy-4,4. ′ -Diaminobenzanilide and 2′-methoxy-4,4′-diaminobenzanilide, and more preferably 2′-methoxy-4,4′-diaminobenzanilide from the viewpoint of ease of synthesis.

Also, as an example of x = 1, Etc. Such compounds are known, for example, in the above-mentioned US Pat. No. 3,179,635 and West German Patent 2,255,652, or can be synthesized by applying the method described therein.

Specific examples of the aromatic tetracarboxylic acid represented by the general formula (IV) or a derivative thereof include those in which four carboxy groups or derivatives thereof are bonded to an aromatic ring. Specific examples thereof include the following. Something like this. In addition,
Although tetracarboxylic acid is exemplified here, ester compounds, acid anhydrides and acid halides thereof can of course be used. Pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 2,3,3 ', 4'-diphenyl ether tetracarboxylic acid, 2,3,3', 4'-benzophenone tetracarboxylic acid, 2,3,6,7-naphthalene tetracarboxylic acid, 1,4,5,7
-Naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 3,3 ', 4,4'-diphenylmethanetetracarboxylic acid, 2,2-bis (3,4-dicarboxyphenyl) propane, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 3,4,9,10-tetracarboxyperylene, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane , 2,2-bis [4- (3,4
-Dicarboxyphenoxy) phenyl] hexafluoropropane, etc., preferably pyromellitic acid, 3,
3 ', 4,4'-biphenyltetracarboxylic acid, 3,3', 4,4 '
-Benzophenone tetracarboxylic acid, 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid. From the viewpoint of low thermal expansion effect, pyromellitic acid or a derivative thereof is preferable, but two or more kinds of tetracarboxylic acid or a derivative thereof may be used for the purpose of improving physical properties or adhesiveness.
The use of an acid anhydride as a derivative of an aromatic tetracarboxylic acid is advantageous in that it is easy to synthesize and there is no harmful by-product.

Although the synthetic reaction of the resin of the present invention can be carried out by the method described in U.S. Pat.No. 3,179,635, etc.,
A raw material containing a diamine represented by the general formula (III) and an aromatic tetracarboxylic acid represented by the general formula (IV) or a derivative thereof, preferably an aromatic tetracarboxylic dianhydride, is preferably N-methyl. Pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAC),
Dimethyl sulfoxide (DMSO), dimethyl sulfate, sulfolane, butyrolactone, cresol, phenol,
In a solvent such as halogenated phenol, cyclohexanone, dioxane, tetrahydrofuran, diglyme,
The reaction is carried out in the range of 0 to 200 ° C, preferably 0 to 100 ° C to produce a polyamideimide precursor represented by the general formula (II), and the polyamideimide precursor is heated to 200 ° C, preferably 2
This is a method of imidizing at a temperature of 50 ° C. or higher to obtain the low thermal expansion resin of the present invention. If the reaction temperature during the production of the polyamideimide precursor of the general formula (II) exceeds 200 ° C., the imidization reaction may proceed during the polymerization reaction, making it difficult to obtain the low thermal expansion effect of the present invention. Also, the moldability is significantly reduced.

In the present invention, the polyamideimide represented by the general formula (I) is used as a constituent unit in an amount of 30 mol% or more, preferably
It is desirable that the content is 40 mol% or more, and more preferably 50 mol% or more. If it is less than 30 mol%, the effect of low thermal expansion is small.

Other structural units include structural units obtained by using various diamines, tetracarboxylic acids, tricarboxylic acids or derivatives thereof such as acid anhydrides, which are randomly entered by random copolymerization. Alternatively, it may be one that is inserted in blocks by block polymerization.

Specific examples of other diamines include p-phenylenediamine, m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane and 3,3 '. -Dimethyl-4,4'-diaminodiphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane,
1,2-bis (anilino) ethane, diaminodiphenyl sulfone, diaminobenzanilide, diaminobenzoate, diaminodiphenyl sulfide, 2,2-bis (p-
Aminophenyl) propane, 2,2-bis (p-aminophenyl) hexafluoropropane, 1,5-diaminonaphthalene, diaminotoluene, diaminobenzotrifluoride, 1,4-bis (p-aminophenoxy) benzene, 4, 4'-bis (p-aminophenoxy) biphenyl, diaminoanthraquinone, 4,4'-bis (3-aminophenoxyphenyl) diphenyl sulfone, 1,3-bis (anilino) hexafluoropropane, 1,4-bis (anilino ) Octafluorobutane, 1,5-bis (anilino) decafluoropentane, 1,7-bis (anilino)
Tetradecafluoroheptane, the following general formula Or (However, in the formula, R5 and R7 represent a divalent organic group, and R4 and R6
Represents a monovalent organic group, and p and q represent integers greater than 1), 2,2-bis [4
-(P-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (3-aminophenoxy)
Phenyl] hexafluoropropane, 2,2-bis [4-
(2-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (4-aminophenoxy)-
3,5-Dimethylphenyl] hexafluoropropane, 2,2
-Bis [4- (4-aminophenoxy) -3,5-ditrifluoromethylphenyl] hexafluoropropane, p
-Bis (4-amino-2-trifluoromethylphenoxy) benzene, 4,4'-bis (4-amino-2-trifluoromethylphenoxy) biphenyl, 4,4'-bis (4-amino-3-tri) Fluoromethylphenoxy) biphenyl, 4,4'-bis (4-amino-2-trifluoromethylphenoxy) diphenyl sulfone, 4,4'-bis (3-amino-5-trifluoromethylphenoxy)
Diphenyl sulfone, 2,2-bis [4- (4-amino-3-trifluoromethylphenoxy) phenyl] hexafluoropropane, benzidine, 3,3 ', 5,5'-tetramethylbenzidine, octafluorobenzidine, 3 ,
3'-dimethoxybenzidine, o-tolidine, m-tolidine, 2,2 ', 5,5', 6,6'-hexafluorotrizine,
There are diamines such as 4,4 ″ -diaminoterphenyl and 4,4-diaminoquaterphenyl.

Examples of other tetracarboxylic acids and their derivatives include the following. Although tetracarboxylic acid is exemplified here, ester compounds, acid anhydrides and acid halides thereof can of course be used. Examples include butanetetracarboxylic acid and cyclopentanetetracarboxylic acid, and also trimellitic acid and its derivatives.

Furthermore, it is also possible to introduce a crosslinked structure or a ladder structure by modifying with a compound having a reactive functional group. For example, there are the following methods.

By modifying with a compound represented by the general formula,
Introduce a pyrrone ring or isoindoloquinazolinedione ring.

[However, an aromatic organic group R8 is 2 + z value in the formula (z is 1 or 2), B is _a -NH ₂ group, -CONH ₂ group or -SO ₂ N
It is a substituent selected from the H ₂ group and is in the ortho position with respect to the amino group] Amine having a polymerizable unsaturated bond, diamine, dicarboxylic acid, tricarboxylic acid, modified with a derivative of tetracarboxylic acid, at the time of curing Form a bridge structure. As the unsaturated compound, maleic acid, nadic acid, tetrahydrophthalic acid, ethynylaniline and the like can be used.

A network structure is formed by modifying with an aromatic amine having a phenolic hydroxyl group or a carboxylic acid and using a crosslinking agent capable of reacting with the hydroxyl group or the carboxyl group.

The linear expansion coefficient of the polyamide-imide resin of the present invention can be adjusted by modifying it with each of the above components. That is, the polyamide-imide resin having only the structure of the general formula (I) has an in-plane 1 × 10 ⁻⁵ (K
^-1 ) It is possible to form an insulator having the following linear expansion coefficient, but by modifying it using the above-mentioned components,
The linear expansion coefficient can be arbitrarily increased.

In the present invention, in order to obtain a resin having a lower thermal expansion coefficient, it is preferable that the polyamic acid solution is applied onto an arbitrary support, dried with a solvent, and further imidized on the support or in a tensioned state. Further, it is also possible to carry out an operation such as stretching to further reduce the thermal expansion. On the contrary, when the imidization reaction is carried out without tension, the linear expansion coefficient tends to increase.

In the present invention, the solvent drying temperature and the imidization temperature can be arbitrarily selected. The imidization temperature is usually 200 ° C or higher, preferably 250 ° C or higher. Further, it is possible to raise the temperature above the glass transition temperature.

In the present invention, when the low thermal expansion polyamide imide and the inorganic material are integrated, the surface of the inorganic material is roughened, or a silane coupling agent, a titanate coupling agent, an aluminum alcoholate, an aluminum chelate, a zirconium chelate, or an aluminum acetylacetone is used. It is also possible to further improve the adhesive strength by carrying out a surface treatment by the above method. Further, by using a polyimide or its precursor, which is more excellent in adhesive strength to the surface of the inorganic material, as an anchor coat, it is possible to improve the adhesive strength of the low thermal expansion resin of the present invention coated thereon. You can

In the present invention, in order to lower the coefficient of linear expansion, increase the coefficient of elasticity, control the fluidity, or reduce the cost, powders of inorganic, organic or metal, fibers, chopped strands, etc. are mixed. It can also be used. It is also possible to blend a polyimide or a precursor thereof, which has been separately synthesized, and polyamide imide.

The low thermal expansion resin of the present invention has a linear expansion coefficient of 16 × 10 ⁻⁶ (K
^-1 ) It is desirable that it is below. If it is larger than this, when applied on a metal plate or an inorganic plate, deformation such as curl,
Film cracking, peeling, substrate damage, etc. occur. here,
The linear expansion coefficient was measured by applying a polyamideimide precursor solution on a copper foil and curing it, and then removing the copper foil by etching and heating the resulting 25 μm film to 250 ° C.
What is calculated as the average of the dimensional change rate between 240 ℃ and 100 ℃ after cooling at ℃ / min. It is the value obtained by.

Further, the water absorption rate is desirably 3% or less. If it is larger than this, not only swelling and peeling occur between the base material and the resin serving as the insulating material during soldering, but also the insulating property is deteriorated. Here, the water absorption rate, the rate of change in weight after immersion of the film obtained in the same manner as above for 24 hours at room temperature,
That is, It is a value obtained from.

The low thermal expansion resin of the present invention can be used for molded articles, films, adhesives, paints, etc., but its high heat resistance, low coefficient of linear expansion and water absorption, high electrical insulation, high bending resistance It is useful as a film, coating material, etc. in the fields requiring heat resistance or electrical insulation resistance. For example, flexible printed boards, multilayer wiring boards, flat cables, film carriers, IC or LSI coating agents, optical fiber secondary Examples thereof include coating materials, solar cells, and other sheets and adhesives that are required to have light resistance and dimensional stability.
It is also possible to introduce a photosensitive group into a photosensitive polyamideimide resin.

When the polyamideimide is used as a film for a flexible printed board, a flat flexible printed board which does not curl while maintaining the mechanical properties of conventional polyimide can be obtained. Further, a manufacturing method in which the polyamideimide precursor solution is directly applied to the copper foil without using an adhesive is possible. Therefore, the manufacturing process is reduced to less than half as compared with the conventional method in which a film and a metal foil that are prepared in advance are attached with an adhesive, and the problem that the heat resistance due to the low temperature curing adhesive is significantly reduced. Does not occur. Further, the flame retardancy is not lowered by the adhesive, and the circuit material has high reliability. Furthermore, the flexible printed circuit board made of the polyamide-imide resin of the present invention does not require pre-drying when soldering because it has high adhesiveness of copper foil and low water absorption. If the water absorption is large, swelling or peeling occurs between the copper foil and the resin without drying.

Similarly, when used as a film carrier, the manufacturing process is simplified and the reliability is high. And as a coating agent for IC and LSI, passivation,
Polyimide varnish is used for the purpose of α-ray shielding, etc., but also by using the resin of the present invention, the stress strain due to the difference in the linear expansion coefficient between the chip and the chip becomes small, and the reliability is high. Become. Moreover, since the adhesiveness is high, peeling is unlikely to occur. In addition, the physical properties of the coating are even better,
Since the water absorption is also low, there is little deterioration in reliability due to corrosion of aluminum wiring.

Further, also in the optical fiber coating material, by using it as a secondary coating material, the difference in the coefficient of linear expansion from the core can be made small, whereby the distortion can be made small and the optical loss can be made small. Furthermore, when the metal foil coated with the polyamide-imide resin of the present invention is used as a substrate for an amorphous solar cell, the occurrence of cracks in the amorphous silicon thin film is significantly reduced.

INDUSTRIAL APPLICABILITY The resin of the present invention has a low thermal expansion property, has good bending resistance and adhesiveness, and has a low water absorption coefficient, and thus is extremely useful as another industrial material.

[Examples] Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples.

For the linear expansion coefficient, use a sample for which the imidization reaction has been completed,
Using a thermomechanical analyzer (TMA), apply the polyamideimide precursor solution on the copper foil, imidize it, and then dissolve and remove the copper foil to obtain a 25 μm film and raise the temperature to 250 ° C. 240 ℃ by cooling at ℃ / min.
The average linear expansion coefficient from 1 to 100 ° C was calculated.

For adhesive strength, using Tensilon tester, fix the resin side of the copper clad product with a width of 10 mm to the aluminum plate with double-sided tape,
It was determined by peeling in the direction of ° C.

The water absorption rate was determined by immersing the film obtained in the same manner as in the measurement of the linear expansion coefficient in water at room temperature for 24 hours, and measuring the weight change before and after.

The bending resistance test uses a sample with a width of 10 mm and a thickness of about 25 μm, manufactured by Toyo Seiki Co., Ltd. MIT soft fatigue tester (chuck 0.38 mmR,
The load was 1 kg).

In addition, the intrinsic viscosity of the polyamideimide precursor before imidization was measured at 30 ° C. in a 0.5 g / dl solution of DMAc solvent.

The abbreviations in each example are as follows.

PMDA: pyromellitic dianhydride BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride DDE: 4, 4'-diaminodiphenyl ether DDM: 4,4'-diaminodiphenylmethane o-TLDN: o-tolidine DABA: 4,4'-diaminobenzanilide Mt-DABA: 2'-methyl-4,4'-diaminobenzanilide Cl-DABA: 2'-chloro-4,4'-diaminobenzanilide 2'-Mo-DABA: 2'-methoxy-4,4'-diaminobenzanilide 2-Mo-DABA: 2-methoxy-4,4'-diaminobenzanilide 2,2'-dMo-DABA: 2,2'-dimethoxy-4,4'-diaminobenzanilide 4,5'-dA-2'-MoBA: 4,5'-diamino-2'-methoxybenzanilide B (4A, 2Mo) TPA: bis (4-amino-2-methoxy) terephthalanilide 2'-Eo-DABA: 2'-ethoxy-4,4'-diaminobenzanilide DMAc: Dimethylacetamide NMP: N-methyl-2-pyrrolidone Example 1 2'while flowing 200 ml of nitrogen per minute into a 300 ml four-necked flask equipped with a thermometer, a calcium chloride tube, a stir bar and a nitrogen inlet. -Mo-DABA: 0.075 mol and DMAc: 170 ml were added and stirred. It was not possible to dissolve all of the 2'-Mo-DABA. While cooling this solution to 10 ° C or lower in a water-cooled bath, PMDA (0.075 mol) was gradually added to the solution.
Mo-DABA reacted while gradually dissolving.

When reacted for about 20 minutes, DDE: 0.025 mol, BTDA: 0.025 mol
Molar and DMAc: 50 ml were added. Then, stirring was continued at room temperature for about 2 hours to carry out a polymerization reaction to obtain a block polymer.

This resin solution was coated on an electrolytic copper foil fixed on an aluminum plate using an applicator so that the film thickness would be about 25 μm, and then sequentially placed in a forced air oven at 130 ° C and 150 ° C for 10 hours.
It was left for minutes for predrying, and then left in a circulating hot air oven at 300 ° C. for 15 minutes for imidization. After cooling, the copper foil was dissolved and removed to obtain a film.

The coefficient of thermal expansion of this film was 8 × 10 ⁻⁶ (K ⁻¹ ). The water absorption was 2.8%, and the bending resistance test was 50,000 times or more.

In addition, this resin solution is fixed on an aluminum plate to a commercially available thickness.
Coated with an applicator on a 35μm electrolytic copper foil to a film thickness of about 25μm,
The mixture was left to stand in a forced air oven at 50 ° C for 10 minutes, and then heated to 330 ° C over 15 minutes to imidize. A sample with almost no curl was obtained. The adhesive strength of this copper-clad product is 1.4kg /
It was cm. After holding this copper-clad product at 76% RH for 24 hours,
It was immersed in a solder bath at 260 ° C for 10 seconds, but no change was observed.

Further, the film of the polyamideimide precursor and the film after imidization were subjected to infrared absorption analysis. First in the case of a film of polyamide-imide precursor
The figure and the case of the film after imidization are shown in FIG. 2, respectively.

Example 2 2'-Mo-DABA: 0.090 mol, DDM: 0.010 in a four-necked flask.
Molar and DMAc: 170 ml added, PMD with stirring under cooling
A: 0.090 mol and BTDA: 0.010 mol were gradually added. When stirring was continued at room temperature for about 2 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film obtained by this is 3 × 10
^The water absorption was 2.8% at ^-6 (K ^-1 ), and the bending resistance test was 50,000 times or more. The adhesive strength of the copper-clad product with this resin was 1.0 kg / cm, and no abnormality due to solder was confirmed.

Examples 3 and 4 Instead of 2'-Mo-DABA of Example 1, 2-Mo-DABA and 2,
It was performed using 2'-dMo-DABA. The evaluation results are shown in Table 1.

Example 5 As in Example 2, 2'-Mo-DABA: 0.
10 mol and DMAc: 170 ml were added, and PMDA:
0.10 mol was added slowly. When the stirring was continued at room temperature for about 2 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film thus obtained is 1 × 10
^The water absorption was 2.8% at ^-6 (K ^-1 ). First evaluation result
Shown in the table.

Example 6 As in Example 2, 2'-Mo-DABA: 0.
10 mol and NMP: 170 ml were added, and BPDA: 0.
10 mol was added slowly. When the stirring was continued at room temperature for about 3 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film obtained by this is 15 × 10
^The water absorption was ^-6 (K ^-1 ) and was 2.0%. First evaluation result
Shown in the table.

Example 7 As in Example 2, 4,5'-dA-2 'was added to a four-necked flask.
-MoBA: 0.10 mol and DMAc: 170 ml were added, and PMDA: 0.10 mol was gradually added while cooling and stirring. When the stirring was continued at room temperature for about 3 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film thus obtained is 14 × 10
^The water absorption was 2.9% at ^-6 (K ^-1 ). First evaluation result
Shown in the table.

Example 8 As in Example 2, B (4A, 2Mo) TPA:
0.075 mol, DDE: 0.025 mol and DMAc: 170 ml were added, and PMDA: 0.10 mol was gradually added while cooling and stirring. When the stirring was continued at room temperature for about 3 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film obtained by this is 12 × 10
^The water absorption was 2.8% at ^-6 (K ^-1 ). First evaluation result
Shown in the table.

Example 9 As in Example 2, 2'-Eo-DABA: 0.
049 mol, DDE: 0.051 mol and DMAc: 170 ml were added, and PMDA: 0.1 mol was gradually added with cooling and stirring. When the stirring was continued at room temperature for about 2 hours, a viscous resin solution was obtained.

The linear expansion coefficient of the film obtained by this is 15 × 10
^{At -6} (K ^-1 ), the water absorption was 2.5%. First evaluation result
Shown in the table.

Comparative Examples 1 to 3 Instead of 2'-Mo-DABA of Example 1, DABA, Mt-DABA and
It was performed using Cl-DABA. The evaluation results are shown in Table 1.

Comparative Example 4 o-TLDN as an amine component and BPDA as an acid anhydride component
Polymerization was carried out in NMP in the same manner as in Example 2 and evaluated. The obtained resin was a resin having low bending resistance. The evaluation results are shown in Table 1.

Comparative Example 5 Polymerization was carried out in DMAc in the same manner as in Example 2 using DDE as the amine component and PMDA as the acid anhydride component, and evaluated. The obtained resin had a large coefficient of thermal expansion. The evaluation results are shown in Table 1.

[Effects of the Invention] The low thermal expansion resin of the present invention has excellent properties in mechanical properties such as bending resistance and adhesiveness, and also has improved water absorption, and thus has a flexible printed circuit board, a film carrier, an IC. It is also useful as a resin for the production of coating agents for LSIs, secondary coating materials for optical fibers, amorphous solar cells, and other sheets, coating materials, adhesives, etc., which are required to have light resistance and dimensional stability.

[Brief description of drawings]

1 and 2 are infrared absorption analysis charts of the polyamideimide precursor film obtained in Example 1 and the film after imidization thereof.

Claims (3)

[Claims] 1. The following general formula (I): [In the formula, Ar represents a tetravalent aromatic group, and R is the following general formula (a) and / or (b). (Wherein R1 to R3 represent the same or different alkyl groups, alkoxy groups or halogens, l, m and n are integers of 0 to 4 and have at least one alkoxy group), and x is 5 to 1,000. Is an integer of 3]
Structural unit 0 to 100 mol%, derived from a tetracarboxylic acid and / or a tricarboxylic acid and a diamine containing no structure represented by the above (a) and / or (b) in the molecule
A low thermal expansion resin characterized by comprising 70 mol%. ] 2. The low thermal expansion resin according to claim 1, wherein the alkoxy group is a lower alkoxy group having 3 or less carbon atoms. 3. The low thermal expansion resin according to claim ^{1, which} has a linear expansion coefficient of 16 × 10 ⁻⁶ (K ⁻¹ ) or less.