JPH0372528A - Fluorinated polyimide and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a fluorinated polyimide having a coefficient of thermal expansion, a dielectric constant, and a refractive index respectively lower than those of conventional polyimides by introducing a fluoroalkyl group into an acid anhydride and a diamine. CONSTITUTION:This fluorinated polyimide has repeating units of formula I (wherein R1 is a tetravalent organic group selected from those of formulas II, III, etc.) and is formed by reacting 2,2'-bis(trifluoromethyl)-4,4'- diaminobiphenyl of formula IV with a tetracarboxylic acid dianhydride selected from those of formulas V, VI, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluorine-containing polyimide having a low dielectric constant, low refractive index, and low coefficient of thermal expansion, and a method for producing the same.

[Conventional technology]

Among various organic polymers, polyimide has excellent heat resistance, so it is beginning to be used in a wide range of fields, from space and aviation to electronic communications. Particularly recently, materials are expected not only to have excellent heat resistance but also to have various performances depending on the purpose. For example, printed circuit boards and interlayer insulating films for LSIs are expected to have low coefficients of thermal expansion and dielectric constants, and cladding materials for optical communications, particularly optical waveguides, are expected to have low refractive indexes. In addition, in order to maintain stable physical property values, it is necessary to have a low water absorption rate. However, a polyimide that fully satisfies these properties has not been obtained. In order to obtain these polyimides, the main chain of the polyimide is made as rigid as possible to exhibit low thermal expansion, and the monomer tetracarboxylic dianhydride or diamine has low dielectric constant and low refractive index properties. One possible method is to introduce a substituent to be expressed. For example, regarding epoxy resins, the Journal of Polymer Science (Journal of Polymer 5c)
(Part) C, Polymer
As shown in Polymer Letters, Vol. 24, p. 249 (1986), by introducing polyfluorine substituents into the curing agent of epoxy resins, we achieved the lowest dielectric properties of any epoxy resin to date. rate has been achieved. Furthermore, as shown in JP-A No. 61-44969, the lowest refractive index of any epoxy resin to date has been achieved by introducing a polyfluorine substituent. By making the polyimide skeleton into a rigid structure and introducing fluorine substituents in this way, reductions in the coefficient of thermal expansion, dielectric constant, and refractive index can be expected.

However, there has been no report to date of achieving low dielectric constant, low refractive index, and low coefficient of thermal expansion by introducing fluorine substituents into polyimide having a rigid structure.

In addition, 2.2'-
3,3'-bis(trifluoromethyl)4.4 is an isomer of bis(trifluoromethyl)-4,4'-diaminobiphenyl and has the following molecular structure.
It has been shown that the material using '-diaminobiphenyl has a very low coefficient of thermal expansion, and has a significantly high mechanical strength and elastic modulus, so that it can be used as a low thermal expansion material. However, the synthesis method of the same material as the present invention and the physical property values such as thermal expansion coefficient, dielectric constant, refractive index, and thermal decomposition temperature have not been reported at all. Furthermore, as a result of studies conducted by the present inventors, 2,2'-bis(trifluoromethyl)-4 according to the present invention
, 4'-diaminobiphenyl is a fluorinated polyimide using 3,3'-his(trifluoromethyl) described in the detailed description of the invention in JP-A-60-250031.
It was revealed that the degree of polymerization was higher and the mechanical strength was much greater than when -4,4'-diaminobiphenyl was used. This means that 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl is 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl
This is because the trifluoromethyl group is located at the meta position of the amino group compared to (trifluoromethyl)-4,4'-diaminobiphenyl, which improves the reactivity between the diamine and the acid dianhydride.

Also, JP-A-62-280257 and JP-A-61-
176198, etc., it is shown that a material having the same molecular structure as a part of the present invention can be applied as a module wiring board or a low viscosity varnish, but the coefficient of thermal expansion, dielectric constant, No value of pyrolysis temperature is reported.

[Problem to be solved by the invention]

An object of the present invention is to provide a polyimide that has a low coefficient of thermal expansion, a low dielectric constant, and a low refractive index that conventional polyimides do not have, and a method for producing the same.

[Means to solve the problem]

To summarize the present invention, the first invention of the present invention relates to a fluorine-containing polyimide, which has the following general formula I: (wherein R1 is the following structural formula 20CF).

It is characterized by having a repeating unit represented by (representing a tetravalent organic group selected from the group consisting of groups represented by).

Further, the second invention of the present invention relates to a method for producing the fluorine-containing polyimide of the first invention, which has the following structural formula
: 2,2'-bis(trifluoromethyl) represented by 3C4.
It is characterized by reacting 4'-diaminobiphenyl with a tetracarboxylic dianhydride selected from the following structural formula group.

Furthermore, the third invention of the present invention is an invention relating to another fluorine-containing polyimide, which has the following general formula (■): 0 (wherein R is selected from the group consisting of groups represented by the following structural formula: CF3). It represents a tetravalent organic group.In the formula, R2 represents a divalent organic group selected from the group consisting of tetracarboxylic dianhydride represented by the following structural formula. It is characterized by having a repeating unit represented by

Furthermore, the fourth invention of the present invention is an invention relating to the method for producing the fluorine-containing polyimide of the third invention, which has the following general formula (■): 0 <wherein R is the following structural formula: CF3 CF3 CF .

A tetracarboxylic dianhydride represented by (representing a tetravalent organic group selected from the group consisting of groups represented by) and the following one-ship formula V: 11, N - R, -N) 1. ... [V] (
In the formula, R2 is a diamine represented by the following structural formula: (represents a divalent organic group selected from the group consisting of groups represented by the following).

The fifth invention of the present invention relates to another fluorine-containing polyimide, which has the following general formula: [In the formula, R is a tetravalent organic group selected from the following general formula (n is 1 Indicates an integer of ~3> :CnF2n++
CnFzh++CIIF2n+1 R2 represents a divalent organic group selected from the following general formula, and is characterized by containing a repeating unit represented by: RISR2 has a fluorine-containing substituent on at least one side.

Furthermore, a sixth invention of the present invention is an invention relating to a method for producing the fluorine-containing polyimide of the fifth invention, which comprises a tetracarboxylic dianhydride represented by the following general formula General formula■
: +12N R2Nl2...
It is characterized by reacting with a diamine represented by [■] (in each of the above formulas, R1 and R2 have the same meaning as the formula (2) in the fifth invention).

The present inventors conducted various studies on the molecular structure of fluorinated polyimide, and by introducing fluorinated alkyl groups into acid anhydrides and diamines, we created a polyimide with a lower dielectric constant, refractive index, and water absorption than conventional polyimides. revealed that it can be obtained.

The diamino used in the present invention includes 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3
．． 3'-dimethyl-4,4-diaminobiphenyl, 4.
Examples include 4'-diamino-p-terphenyl. Among these, 2,2'-bis(trifluoromethyl)-4,4
A method for producing '-diaminobiphenyl is described, for example, in Journal of the Chemical Society of Japan, No. 3, pp. 675-676 (1972). Moreover, the tetracarboxylic dianhydride used in the present invention is pyromellitic anhydride, 3.3'.

4.4'-benzophenone tetracarboxylic dianhydride,
3.3',4.4'-biphenyltetracarboxylic dianhydride, 2.2-bis(3,4-dicarboxyphenyl)
-hexafluoropropane dianhydride, trifluoromethylpyromellitic dianhydride, 1,4-di(trifluoromethyl)pyromellitic acid dihydrate, 1,4-di(pentafluoroethyl)pyromellitic acid dianhydride Examples include anhydride, heptafluoropropylpyromellitic dianhydride, and the like.

Among them, trifluoromethylpyromellitic dianhydride, which is a fluorine-containing dianhydride with a fluoroalkyl group introduced into the benzene ring of pyromellitic acid, and 1,4-cy(trifluoromethyl)pyromellitic dianhydride. thing, ・1.4-di(
Methods for producing pentafluoroethyl)pyromellitic dianhydride, pentafluoropropylpyromellitic dianhydride, etc. are described in Japanese Patent Application No. 165056/1983. Polyamic acid is produced by reacting these diamines with tetracarboxylic dianhydride.

The reaction conditions may be the same as those for ordinary polyamic acid polymerization;
The reaction is carried out in a polar organic solvent such as dimethylacetamide or dimethylformamide.

Next, a polyimide synthetic leather is obtained by imidizing the obtained polyamic acid, and a normal polyimide synthesis method can be used for this as well.

〔Example〕

EXAMPLES The fluorine-containing polyimide of the present invention and the method for producing the same will be explained in detail below with reference to Examples, but the present invention is not limited to these Examples.

Imidization was confirmed by the characteristic absorption caused by symmetric and asymmetric stretching vibrations of the carbonyl group in the infrared absorption spectrum. In addition, in each example below, the dielectric constant is the value at 1 kHz, and the refractive index is the wavelength of the IJum D line (589, 6n
m) Te(7)(a (20°C).Thermal decomposition temperature,
The glass transition temperature was measured at a heating rate of 1017 minutes under a nitrogen stream. The coefficient of thermal expansion was determined by attaching the film heated and manufactured under the conditions described in Example 1 to a thermomechanical testing machine at a heating rate of 5° C./min.

Example 1 4.36 g (20.0 mmol) of pyromellitic dianhydride having the following structural formula and 2,2'-bis(trifluoromethyl)-4゜4 having the following structural formula were placed in an Erlenmeyer flask. '-diaminobiphenyl 6.40 g (20.0 mmol), and N,N-
100 g of dimethylacetamide (DMA) was added.

This mixture was stirred at room temperature under a nitrogen atmosphere for 31 minutes to obtain a DMA solution of polyamic acid.

The viscosity of this solution was approximately 80 poise. This material was spin-coated on an aluminum plate and heated for 70 minutes under a nitrogen atmosphere.
C. for 2 hours, 160.degree. C. for 1 hour, 250.degree. C. for 30 minutes, and then heated at 350 tons for 1 hour. This aluminum plate was immersed in a 10% HCI aqueous solution, and the aluminum plate was dissolved to obtain a polyimide film. When this infrared absorption spectrum was measured, absorptions specific to the imide group were found at 1740 and 1790.
cm-', and it was confirmed that imidization had completely progressed. The thermal decomposition temperature of this material is 610℃, the glass transition temperature is 365℃, the dielectric constant is 3.2, the refractive index is 1.65,
The coefficient of thermal expansion was 3.3 x l 0-6 (-').

Example 2 The pyromellitic dianhydride in Example 1 was converted to 3,3',4,4'-biphenyltetracarboxylic dianhydride represented by the following structural formula 111 0 5.88 g (20, Ommol) The same procedure as in Example 1 was carried out except that . The properties of the synthesized polyimide are shown in Table 1 below along with other examples.

Example 3 Pyromellitic dianhydride in Example 1 was replaced with 6.44 g (20, Ommol) of 3,3',4,4'-benzophenonetetracarboxylic dianhydride represented by the following structural formula. , in the same manner as in Example 1. Table 1 shows the properties of the synthesized polyimide.

Example 4 The pyromellitic dianhydride in Example 1 was converted to 8.88 g (20, Ommol ) was carried out in the same manner as in Example 1. Table 1 shows the properties of the synthesized polyimide.

Example 5 The same procedure as in Example 1 was carried out except that pyromellitic dianhydride in Example 1 was replaced with 5.72 g (20, Ommol) of trifluoromethylpyromellitic dianhydride represented by the following structural formula. Ta. Table 1 shows the properties of the synthesized polyimide.

Example 6 Pyromellitic dianhydride in Example 1 was replaced with 7.08 g (20, Ommol) of 1,4-di(trifluoromethyl)pyromellitic dianhydride shown by the following structural formula, The same procedure as in Example 1 was carried out. Table 1 shows the properties of the synthesized bo1r imide.

Example 7 Pyromellitic dianhydride in Example 1 was replaced with trifluoromethylpyromellitic dianhydride 5.72 g (20
, Ommol), and 2 in Example 1,
2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl was replaced with 4.25 g (20,0+++ mol) of 3,3'-dimethyl-4,4'-diaminobiphenyl shown by the following structural formula. The same procedure as in Example 1 was carried out. Table 1 shows the properties of the synthesized polyimide.

Example 8 The pyromellitic dianhydride in Example 1 was replaced with 5.72 g of trifluoromethylpyromellitic dianhydride (20,
Ommol), and 2, 2 in Example 1
5.21 g (20, Ommol
) was carried out in the same manner as in Example 1. Table 1 shows the properties of the synthesized polyimide.

Example 9 Pyromellitic dianhydride in Example 1 was replaced with 1,4-di(trifluoromethyl)pyromellitic dianhydride 7.0
8 g (replaced with 20.0 mm, and Example 1
2,2'-bis(trifluoromethyl)-4,
4'-diaminobiphenyl to 3,3'dimethyl-4,4
'-diaminobiphenyl 4.25g (20.0mmo
The same procedure as in Example 1 was carried out except that 1) was replaced. Table 1 shows the properties of the synthesized polyimide.

Example 10 The pyromellitic dianhydride in Example 1 was replaced with 1.4-di(trifluoromethyl)pyromellitic dianhydride 7.0
8g (20, Ommol) and Example 1
2,2'-bis(trifluoromethyl)-4,
The same procedure as in Example 1 was carried out except that 4'-diaminobiphenyl was replaced with 5.21 g (20, Ommol) of 4.4'diamino-p-terphenyl.

Table 1 shows the properties of the synthesized polyimide.

Example 11 The pyromellitic dianhydride in Example 1 was converted to 11.08 g of 1,4-di(heptafluoropropyl)pyromellitic dianhydride represented by the following structural formula (20, Ommo
The same procedure as in Example 1 was carried out except that 1) was replaced. Table 1 shows the properties of the synthesized polyimide.

Example 12 The pyromellitic dianhydride in Example 1 was replaced with 1.4-cy()lyfluoromethyl)pyromellitic dianhydride 7.0
8 g (20, Ommol) and 2,2'-bis(trifluoromethyl)-4 in Example 1.
, 4'-diaminobiphenyl was prepared in the same manner as p-phenylenediamine Example 1 shown by the following structural formula. Table 1 shows the properties of the synthesized polyimide.

Example 13 Pyromellitic dianhydride in Example 1 was replaced with pentafluoroethylpyromellitic dianhydride 0 6,72 g (20, Ommol) shown by the following structural formula, and 2 in Example 1, 2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl is converted into 2,5-diaminotoluene 2,16 g (20
, Ommol) and carried out 2.44 g (2
The same procedure as in Example 1 was carried out except that 0.0, Ommol) was used. Table 1 shows the properties of the synthesized polyimide.

Comparative Example 1 Using the same method as in Example 1, a commercially available polyimide (trade name Upilex ) was obtained. The properties of this product are shown in Table 1.

Comparative Example 2 3.3', 4.4 using the same method as Example 1
'.

Benzophenone tetracarboxylic dianhydride and 4゜4'-
Polyimide was obtained using equimolar amounts of diaminodiphenyl ether. The properties of this product are shown in Table 1.

Comparative Example 3 Pyromellitic dianhydride 4 was prepared in the same manner as in Example 1.
．． 36 g (20.0 mmol) and 4.4' of 3,3'-bis(trifluoromethyl) shown by the following structural formula.
- A DMA solution of polyamic acid was obtained using 6.40 g (20.0 mmol) of diaminobiphenyl. The viscosity of this product was low, and the mechanical strength of the polyimide after heat curing was extremely low. Therefore, it was impossible to measure the dielectric constant, refractive index, and coefficient of thermal expansion.

Comparative Example 4 Pyromellitic dianhydride in Comparative Example 3 was replaced with 8.88 g (20.0 mmol) of 2,2-bis(3,4-dicarboxyphenyl>hexafluoropropane dianhydride), and Comparative Example 3 and The same procedure was carried out.D of polyamic acid
The viscosity of the MA solution was low, and the mechanical strength of the polyimide after heat curing was extremely low. Therefore, the dielectric constant,
It was not possible to measure the refractive index and thermal expansion coefficient.

From these results, the fluorine-containing polyimide of the present invention has a lower dielectric constant and lower refractive index than conventional ones. It has also been revealed that the coefficient of thermal expansion can be changed by changing the acid anhydride.

〔Effect of the invention〕

As explained above, the fluorine-containing polyimide of the present invention is
Compared to polyimide using conventional pyromellitic dianhydride, it has the advantages of lower dielectric constant, lower refractive index, and variable thermal expansion coefficient, so it can be used as a material for printed boards, interlayer insulation films for LSI, optical waveguides, etc. can be applied.

Claims (1)

[Claims] 1. The following general formula I: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] (In the formula, R_1 is the following structural 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. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼,▲Mathematical formulas, chemical formulas,
A fluorine-containing product characterized by having a repeating unit represented by (indicates a tetravalent organic group selected from the group consisting of groups represented by ▼, ▲mathematical formulas, chemical formulas, tables, etc.) Polyimide. 2. Structural formula II below: ▲Mathematical formulas, chemical formulas, tables, etc.▼...[II] 2,2'-bis(trifluoromethyl)-4 represented by
, 4'-diaminobiphenyl and the following structural formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Numerical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
The method for producing a fluorine-containing polyimide according to claim 1, characterized in that the reaction is carried out with a tetracarboxylic dianhydride selected from the group consisting of tetracarboxylic dianhydrides represented by ▼. 3. General formula III below: ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [III] (In the formula, R_1 is the following structural formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables etc. ▼ Indicates a tetravalent organic group selected from the group consisting of the groups represented by. In addition, R_2 in the formula is the following structural formula: ▲ mathematical formula, chemical formula,
A fluorine-containing product characterized by having a repeating unit represented by ▼, ▲Mathematical formula, chemical formula, table, etc.▼ (representing a divalent organic group selected from the group consisting of the groups represented by) Polyimide. 4. The following general formula IV: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[IV] (In the formula, R_1 is the following structural formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables etc. ▼ indicates a tetravalent organic group selected from the group consisting of the groups represented by) and the following general formula V: H_2N-R_2-NH_2... [V] (In the formula, R_2 is the following structural formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
4. The method for producing a fluorine-containing polyimide according to claim 3, characterized in that the diamine represented by ▼ (indicating a divalent organic group selected from the group consisting of groups represented by ▼) is reacted. 5. The following general formula VI: ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [VI] [In the formula, R_1 is a tetravalent organic group selected from the following general formula (n is an integer from 1 to 3) ): ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R_2 is a divalent organic group selected from the following general formulas: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Numerical formulas, chemical formulas, tables, etc. There are ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. Fluorine-containing polyimide. 6. The following general formula VII: ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [VII] Tetracarboxylic dianhydride represented by the following general formula V
III: H_2N-R_2-NH_2... [VIII] (In each of the above formulas, R_1 and R_2 are the formula V according to claim 5
6. The method for producing a fluorine-containing polyimide according to claim 5, characterized by reacting the diamine represented by (synonymous with I).