JPH04306234A - New polyimide copolymer - Google Patents

Abstract

PURPOSE:To obtain a new polyimide copolymer having excellent heat resistance, high modulus of elasticity, low thermal expansion, low dielectric constant and low water vapor absorption, comprising an aromatic tetracarboxylic dianhydride having introduced furan ring in the main chain as a production raw material. CONSTITUTION:(A) 3-Bromo- or 3-iodo-o-xylene is reacted with metal magnesium or metal lithium in an ether or aprotic solvent and then with a furan compound to give a compound (e.g. bis-o-xylinofuryl) shown by formula I (m is 1-3), which is oxidized and is subjected to ring closure through dehydration to give an acid anhydride shown by formula II. (B) The acid anhydride shown by formula II is polymerized with a diamine compound (preferably long-chain aromatic diamine) shown by formula III (R is bifunctional organic group) in an equimolar ratio in an organic polar solvent (e.g. dimethyl sulfoxide) to give a solution of a polyamic acid copolymer and the solution is thermally dehydrated or dehydrated with a dehydrating agent to give a new polyimide copolymer having a structural unit shown by formula IV.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a novel polyimide copolymer which has excellent heat resistance, low moisture absorption, and low dielectric constant.

0002

Conventionally, polyimide resins have excellent heat resistance and electrical insulation properties, and have been widely used as industrial materials including electrical equipment. Polyimide resin is
As described above, it has various superior properties compared to other polymers, but as technology advances, the required properties are becoming increasingly sophisticated, and it is desired to have a combination of various performances depending on the application. For example, base films for flexible printed circuit boards and carrier tapes for TAB (tape automated bonding) are desired to have high heat resistance, high modulus of elasticity, low coefficient of thermal expansion, low dielectric constant, and low moisture absorption. It is desired that the dielectric constant, moisture absorption rate, and coefficient of thermal expansion be small for resins for use or interlayer insulating films for LSIs, and in order to obtain polyimide with such characteristics, the present invention An acid anhydride with a structure similar to the acid anhydride used for has been synthesized. However, the emergence of polyimide that achieves both of these properties at a higher level is awaited.

0003

[Problems to be Solved by the Invention] The present invention has a high elastic modulus,
The purpose of the present invention is to provide a polyimide copolymer having excellent properties such as low thermal expansion, low dielectric constant, and low moisture absorption.

0004

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted intensive studies and have found a new polyimide composition having the specific structural unit shown below, and have completed the present invention. That is, the present invention provides the following general formula (I)

[0005]

[Case 2]

(However, m is an integer of 1 to 3, and R represents a divalent organic group.) It contains a novel polyimide copolymer having a structural unit represented by the following formula.

The present invention will be explained in detail below. The present inventors conducted various studies on the molecular structure of polyimide, and
Structural formula (A) below in which a furan ring is introduced into the main chain of biphenyltetracarboxylic acid

[0008]

[Chemical formula 3]

[0009] If a compound represented by (m = an integer of 1 to 3) is used, the molecular weight of the acid anhydride increases, and the proportion of imide rings, which are the polar parts of polyimide, decreases, resulting in a low dielectric constant. , found that low hygroscopicity could be achieved,
It has been found that by reacting this compound with various aromatic diamines, a polyimide copolymer having a lower dielectric constant and moisture absorption rate than conventional polyimides can be obtained. The polyimide copolymer of the present invention is obtained from a polyamic acid copolymer solution which is a precursor thereof, and this polyamic acid copolymer solution can be produced by a known method. That is, it is obtained by using substantially equimolar amounts of acid anhydride and diamine components and polymerizing them in an organic polar solvent.

[0010] As the aromatic tetracarboxylic dianhydride used to obtain the polyamic acid, a compound represented by the above structural formula (A) is suitable. The following structural formula (B) is a raw material for producing the tetracarboxylic dianhydride represented by the above structural formula (A).

[0011]

[C4]

[0012] Bis o-xylinofuryl, bis o-xylinobifuryl, represented by (where m = an integer of 1 to 3);
Bis-o-xylinotafuryl can be synthesized, for example, by the following method. The following reaction formula (C)

[0013]

[C5]

(where X is Br or I, m is an integer of 1 to 3, M is metallic magnesium or metallic lithium), in ether or an aprotic solvent.
-Reacting bromo-o-xylene or 3-iodo-o-xylene with metal magnesium or metal lithium,
Next, the furan compound

[0015]

[C6]

(where X is I or Br, and m is an integer of 1 to 3), the compound represented by the structural formula (B) can be synthesized. In addition, the following reaction formula (
As shown in D), 3-bromo-o-xylene or 3-bromo-o-xylene or 3-bromo-o-xylene in water, methanol, or a mixture of water and methanol
The structural formula ( A compound represented by B) can be synthesized.

[0017]

[C7]

(However, X is Br or I, m is an integer from 1 to 3, and the catalyst is palladium, an alloy of palladium and mercury, or a mixture of palladium chloride and mercuric chloride)

001
9] Next, from bis o-xylinofuryl, bis o-xylinobifuryl, and bis o-xylinotafuryl represented by structural formula (B), a tetracarboxylic dianhydride represented by structural formula (A) is obtained. The oxidation and dehydration reactions can be carried out by conventional oxidation and dehydration ring closure techniques. For example, oxidation of a methyl group by a potassium permanganate method, a nitric acid method, etc., and an acid anhydride method such as an acetic anhydride method, a heat dehydration method, etc. can be adopted. Alternatively, it is also possible to directly convert the acid anhydride by air oxidation using vanadium pentoxide as a catalyst.

In order to synthesize polyamic acid, which is a precursor of the polyimide of the present invention, the acid anhydride of the above structural formula (A) and the general formula H2 N-R-NH2 (wherein R is a divalent A diamine compound represented by an organic group) is used. In particular, in order to obtain polyimide with a low dielectric constant and low moisture absorption rate, structural formula group (E)

[0021]

[Chemical formula 8]

It is desirable to use at least one type of long-chain aromatic diamine as shown in the following. In addition, if you want to further provide properties such as high elastic modulus and low thermal expansion, structural formula group (F)

[0023]

[Chemical formula 9]

At least one highly linear aromatic diamine as shown in (X represents F, Cl, CH3 -- or CH3 O-) can be used. By copolymerizing aromatic diamines such as those shown in structural formula groups (E) and (F) or blending polyamic acids synthesized using these diamines, low water absorption, low dielectric constant, and high It is possible to achieve both high elastic modulus and low thermal expansion.

For example, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,
4'-diaminodiphenylmethane, bis(3-ethyl-
4-aminophenyl)methane, bis(3-methyl-4-
aminophenyl)methane, bis(3-chloro-4-aminophenyl)methane, 2,2',5,5'-tetrachloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfide, 3, 3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether,
4,4'-diaminooctafluorobiphenyl, 2,4
'-Diaminotoluene, metaphenylenediamine, 2,
2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)
phenyl]hexafluoropropane, 2,2-bis(4
-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(
3-hydroxy-4-aminophenyl)propane, 2,
Examples include diamines such as 2-bis(3-hydroxy-4-aminophenyl)hexafluoropropane, 9,9-bis(4-aminophenyl)-10-hydro-anthracene, and orthotolidine sulfone. Also, 3,3'
,4,4'-biphenyltetraamine, 3,3',4,
It is also possible to use some polyvalent amine compounds such as 4'-tetraaminodiphenyl ether.

Examples of the organic polar solvent used in the reaction for producing the polyamic acid copolymer include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamides such as N,N-dimethylformamide and N,N-diethylformamide. -based solvents, acetamide-based solvents such as N,N-dimethylacetamide and N,N-diethylacetamide, pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- , or p-cresol, xylenol,
Examples include phenolic solvents such as halogenated phenol and catechol, hexamethylphosphoramide and γ-butyrolactone, and it is preferable to use these alone or as a mixture of two or more, but furthermore, xylene, toluene, etc. It is also possible to use some aromatic hydrocarbons such as Further, it is desirable from the viewpoint of handling that the polyamic acid copolymer is preferably dissolved in an organic polar solvent in an amount of 5 to 40% by weight, more preferably 10 to 30% by weight.

In order to obtain the polyimide copolymer of the present invention from this aromatic polyamic acid copolymer solution, either a thermal method of thermal dehydration or a chemical method using a dehydrating agent may be used. A chemical method is preferable because the resulting polyimide copolymer has excellent mechanical properties such as elongation and tensile strength. The imidization method is illustrated below.

[0028] The above polyamic acid copolymer solution or a solution prepared by adding a dehydrating agent in a stoichiometric amount or more and a catalytic amount of tertiary amine to the solution is cast or coated on a drum or an endless belt to form a film, The membrane is dried at a temperature below 150° C. for about 5 to 90 minutes to obtain a self-supporting polyamic acid membrane. Then, it is peeled off from the support and the ends are fixed. Thereafter, it is imidized by gradually heating to about 100 to 500°C, and after cooling, it is removed from the drum or endless belt to obtain the aromatic polyimide polymer film of the present invention. Examples of the dehydrating agent mentioned here include aliphatic acid anhydrides such as acetic anhydride, aromatic acid anhydrides, and the like. Examples of catalysts include aliphatic tertiary amines such as triethylamine, and aromatic tertiary amines such as dimethylaniline.
Examples include heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline, which may be used alone or in combination of two or more.

[0029]

[Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. In the examples, BAPP is bis(aminophenoxyphenyl)propane, ODA is 4,4'-diaminodiphenyl ether, PMDA is pyromellitic anhydride, DMF
represents dimethylformamide.

Example 1 DMF and BAPP were placed in a 2-liter separable flask and mixed well at room temperature until the diamino compound was completely dissolved. Next, while cooling the mixed solution with ice, bis(
BA (3-phthalic anhydride)-2,5-furyl
It was added in a substantially equimolar amount with PP and stirred for 1 hour to obtain a DMF solution of polyamic acid. The amount of DMF used was such that the monomer concentration of the diamino compound and aromatic tetracarboxylic acid compound was 18% by weight. A polyamic acid solution was cast onto a glass plate, and after drying at about 100°C for about 60 minutes, the polyamic acid coating was peeled off from the glass plate, the coating was fixed on a support frame, and then heated at about 100°C for about 30 minutes. for about 60 minutes at about 200°C, about 3
Heated at 00℃ for about 60 minutes, dehydrated and ring-closed to a thickness of 25μ.
A polyimide film of m was obtained. Table 1 shows the physical properties of the obtained polyimide film.

Examples 2 to 5 Using the same method as in Example 1, polyimide films of different compositions were obtained. These physical properties are shown in Table 1.

Example 6 1,4-bis(4-
200 mmol of (aminophenyl)benzene and DMF were taken and mixed well at room temperature until the diamino compound was completely dissolved. Next, while cooling the mixture with ice, bis(3-
Phthalic anhydride)-2,5-frill 400mm
After adding ol at once, stir for 30 minutes, then add BAPP20
A DMF solution of polyamic acid was obtained by adding 0 mmol of DMF solution. The amount of DMF used was such that the monomer concentration of the diamino compound and aromatic tetracarboxylic acid compound was 18% by weight. The polyimide film production conditions were the same as in Example 1,
A polyimide film with a thickness of 25 μm was obtained. Table 1 shows the physical properties of the obtained polyimide film.

Comparative Example 1 A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 using equal moles of PMDA and ODA. Table 1 shows the physical properties of the obtained polyimide film.

[0034]

[Table 1]

[0035]

As described above, according to the present invention, a polyimide copolymer having excellent heat resistance, low hygroscopicity, and low dielectric constant can be obtained.

Claims (1)

[Claims] [Claim 1] A novel polyimide copolymer having a structural unit represented by the following general formula (I) [Formula 1] (where m = an integer of 1 to 3, and R represents a divalent organic group) .