WO2008041636A1 - Polyimide and optical waveguide using the same - Google Patents

Abstract

[PROBLEMS] To provide a polyimide which has heat resistance, light transmission properties, a low linear expansion coefficient and insulation-retaining properties and which is useful for an optical material, particularly an optical waveguide. [MEANS FOR SOLVING PROBLEMS] Disclosed is a polyimide which contains no chlorine atom in the molecule, and has a glass transition temperature of 300 ºC or higher, a birefringence index of 0.15 or less and a linear expansion coefficient of 70 ppm/ °C or lower. The polyimide can be produced, for example, by reacting an aromatic tetracarboxylic acid with an aromatic diamine, wherein the aromatic tetracarboxylic acid and the aromatic diamine have the structures shown below, respectively.

Description

 Specification

 Polyimide and optical waveguide using it

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a polyimide for optical materials that can be used for optical waveguide elements, optical fibers, lenses, optical disk substrates and the like having heat resistance and excellent dimensional stability and a low linear expansion coefficient.

In particular, it can be used as an optical material for optical waveguides in opto-electronic integrated circuits (OEIC) and opto-electronic hybrid mounting wiring boards, and it is particularly excellent in optical polyimide that combines heat resistance, low linear expansion coefficient, light transmission characteristics, and insulation sustainability. The present invention relates to an optical material. In the present invention, the polyimide used in polymer optical waveguides is peeled or warped due to the difference in linear expansion coefficient between the silicon substrate and the like, and the polyimide is softened at 320 ° C or higher in Au—Sn solder, resulting in malfunction. The present invention relates to a polyimide for optical materials that solves the problems such as the loss of functionality as an optical component due to the double refraction.

 Background art

 [0002] In the optical communication field, where interest has been increasing recently, optical branching couplers (optical power bras), optical multiplexers / demultiplexers, optical isolators, optical fiber amplifiers, etc. are important optical materials. However, among these, optical waveguide type elements are of particular interest and practical materials are strongly desired. Currently, the optical waveguide element with the highest performance and high reliability is the glass optical waveguide, but there are problems in the process, such as the high temperature process above 1000 ° C in the manufacturing process. Has a problem.

 In order to solve these problems, polymer optical waveguide forces using polymer materials have been proposed recently. Since it has properties such as transparency, heat resistance and low hygroscopicity, many fluorine-containing polyimide resins have been proposed as polymer materials for optical waveguides (see Patent Documents 1 to 4).

As a polymer optical waveguide using a polymer material other than the fluorinated polyimide, an optical waveguide using a polyethylene methacrylate or polycarbonate has been proposed. The polymer material of poly (methyl methacrylate) is inexpensive and easy to process. Polymethyl methacrylate has a low glass transition temperature (Tg) of about 100 ° C, so it can be heated during processing. Therefore, there is a risk of softening, and there is a problem that the refractive index cannot be controlled. [0003] Fluorinated polyimide is transparent in the communication wavelength band (1 · S ^ m, 1.55 m). Although it passes, its linear expansion coefficient is high, so if a wave-guiding layer is formed on a silicon wafer or a synthetic quartz substrate, the substrate is often distorted or peeled off from the substrate.

 In addition, in order to provide a polymer optical waveguide having a core layer and a clad layer made of polyimide that does not cause curl (folding) in the substrate and does not cause solvent cracks in the polyimide layer when multilayered, the polyimide is formed on the substrate. The core layer consisting of 2, 2'-dichloro-4,4 ', 5,5' is a first polyimide obtained by polycondensation of monobiphenyltetracarboxylic dianhydride and aromatic diamine and a cladding layer of 2 , 2'-dichloro-4,4 ', 5,5'-biphenyltetracarboxylic dianhydride, including biphenyltetracarboxylic dianhydride, and second polyimide obtained by polycondensation of aromatic diamine In polymer composite waveguides with fine conductor circuits and optical waveguides mixed together, chlorine is generated from the constituent polyimide by dissociation and decomposition (see Patent Document 5, for example). In many cases, it has a great influence on the insulation failure of the conductor circuit.

[0004] A polymer having a rigid and bulky skeleton has low thermal expansion and excellent dimensional stability due to its rigidity, and has high heat resistance, and the bulky skeleton reduces its polarizability and birefringence. There is an effect that can be reduced. The structure of [Chemical 1] can be cited as a skeleton that can be expected to have such effects.

 Polyimides incorporating this skeleton include 4,4'-one (2,2'-hexafluoroisopropylidene) diphthalic dianhydride and 2,2,1-bis (biphenyl) benzidine. However, due to the flexible structure of 4,4 '-(2,2'-hexafluoroisopropylidene) diphthalic dianhydride, the linear expansion coefficient is 62.3 ppm. There is no solution to distorting or peeling off a substrate as high as / ° C.

 Patent Document 1: Japanese Patent Laid-Open No. 09-021920

 Patent Document 2: Japanese Patent Laid-Open No. 11 147955

 Patent Document 3: Japanese Patent Laid-Open No. 06-208033

 Patent Document 4: Japanese Patent Laid-Open No. 04-009807

Patent Document 5: Japanese Unexamined Patent Publication No. 2005-350562 Non-Patent Document 1: JC Chen, FW Harris, Polymer, 40, 4571 (1999)

 Disclosure of the invention

 Problems to be solved by the invention

[0005] The present invention was made to solve the above-mentioned problems in optical materials, particularly polymer-based optical waveguides, and is a substrate for forming a linear waveguide and a linear expansion coefficient of polyimide as an optical material. As a result, the difference in the coefficient of linear expansion between the glass substrate and the key substrate is small. As a result, the substrate is not curled and the substrate and the optical waveguide are not easily separated. Therefore, an object of the present invention is to provide an optical material, particularly an optical waveguide, which has characteristics that do not cause a poor insulation of a conductor circuit.

 Means for solving the problem

That is, the present invention is based on the following configuration.

 1. a polyimide containing no chlorine atom in the molecule! /, Obtained by reacting an aromatic tetracarboxylic acid and an aromatic diamine, which has a glass transition point of 300 ° C or higher and a birefringence index Polyimide, characterized by having a coefficient of linear expansion of 0.15 or less and a linear expansion coefficient of 70 ppm / ° C or less.

 2. The polyimide according to 1 above, wherein the polyimide has a glass transition point of 320 ° C. or more and a linear expansion coefficient of 40 ppm / ° C. or less.

 3. The polyimide according to 2 above, wherein the molecule does not contain a chlorine atom! /, And the aromatic tetracarboxylic acid includes an aromatic tetracarboxylic acid having a skeleton of the following [Chemical!] To [Chemical 3].

 [Chemical 1]

 [Chemical 2]

[化 3]

[Chemical 3]

 (In [Chemical Formula 1] to [Chemical Formula 3], [Chemical Formula 1] shows two aspects of the phenyl skeleton, [Chemical Formula 2] shows two aspects of the biphenyl skeleton, and [Chemical Formula 3] shows three aspects of the naphthyl skeleton. , X;! To X6 represent a monovalent hydrocarbon aromatic group (phenyl, biphenyl, naphthyl), a monovalent aromatic ether group (phenoxy, biphenoxy, naphthoxy), hydrogen, and each unit (skeleton) ) At least one of them is a monovalent hydrocarbon aromatic group and / or a monovalent aromatic ether group, and the other bonding part represents a carboxylic acid bonding part.

 4. The polyimide as described in 2 or 31 / above, wherein the aromatic diamine contains an aromatic diamine having a skeleton of [Chemical Formula 4] to [Chemical Formula 6] below.

[Chemical 4]

[Chemical 6]

(In [Chemical 4] to [Chemical 6], [Chemical 4] shows two aspects of the phenyl skeleton, [Chemical 5] shows two aspects of the biphenyl skeleton, and [Chemical 6] shows five aspects of the naphthyl skeleton. , X;! To X8 are monovalent hydrocarbon aromatic groups (phenyl, biphenyl, naphthyl), monovalent aromatic ether groups (phenol) Xy, biphenoxy, naphthoxy), hydrogen, and at least one of each unit (skeleton) is a monovalent hydrocarbon aromatic group and / or a monovalent aromatic ether group, and the other bond portion is an amine bond portion. It is shown. )

 5. The polyimide as described in any one of 1 to 4 above, wherein the polyimide has a linear expansion coefficient of 60 ppm / ° C or less and contains the following structural formula [Chemical Formula 7] in the polyimide structure.

 6. The polyimide as described in 5 above, wherein the birefringence of the polyimide is 0.1 or less.

 7. The polyimide according to 1 to 4 above, wherein the polyimide structure contains a diamine skeleton of the following structural formula [Chemical Formula 8].

 [Chemical 8]

 8. The polyimide according to 7 above, wherein the birefringence of the polyimide is 0.05 or less.

 9. An optical waveguide using the polyimide according to the above;! ~ 81 /.

The invention's effect

The polyimide for optical material according to the present invention is a polyimide that does not contain a chlorine atom in the molecule, has a glass transition point of 300 ° C or higher, a birefringence of 0.15 or lower, and a linear expansion coefficient of 70 ppm / ° C or lower. It is a polyimide for an optical material, and its linear expansion coefficient is small and the difference between the linear expansion coefficient of the glass substrate and the silicon substrate is small. Even if a crack layer or core layer is formed, the substrate does not curl and the substrate and the optical waveguide are not easily peeled off. Also, in the composite wiring board in which the conductor circuit and the optical waveguide are mixed, the insulation failure of the conductor circuit Heat resistance, light transmission, low coefficient of linear expansion, insulation maintenance, with characteristics that do not cause malfunction due to deformation of polyimide at a temperature of 320 ° C or higher in Au-Sn solder that is hard to generate And is useful as an optical material, particularly as an optical waveguide.

 BEST MODE FOR CARRYING OUT THE INVENTION

 [0008] The polyimide in the present invention is a polyimide obtained by reacting, for example, an aromatic tetraforce rubonic acid containing no chlorine atom in the molecule with an aromatic diamine, and has a glass transition point of 300 ° C or higher. Any polyimide having a birefringence of 0.15 or less and a linear expansion coefficient of 70 ppm / ° C or less is not particularly limited, but the following aromatic diamines and aromatic tetracarboxylic acid (anhydrous anhydride) Things) are preferred! /, For example.

 Examples of aromatic diamines that can be particularly preferably used in the present invention include the following compounds of [Chemical Formula 9] to [Chemical Formula 26], but are not limited thereto.

 [0009] [Chemical 9]

 [0010] [Chemical 10]

[0011] [Chemical 11]

[0015] [Chemical 15]

[0020] [Chemical 20]

[0024] [Chemical 24]

 In the present invention, one or more diamines exemplified below may be used in combination with the above diamine. Preferably, it is less than 50 mol%, or less than 30 mol%, further less than 20 mol% of all diamines (including diamine and amide bond derivatives).

Examples of such diamines include 5-amino-2- (p-aminophenyl) benzoxazole, 6-amino-2- (p-aminophenyl) benzoxazole, and 5-amino-2- (m-aminophenol). Benzoxazole, 6-amino-2- (m-aminophenyl) Benzoxazole, 4, 4, 1-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4— (3-Aminophenoxy) phenol] sulfide, bis [4— (3-aminophenoxy) phenol] sulfone, 2,2-bis [4— (3-aminophenoxy) phenol] propane, 2 , 2-bis [4- (3-Aminophenoxy) phenyl] — 1, 1, 1, 3, 3, 3—Hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p— Fenji Rangemi , M-aminobenzinoleamine, p-aminobenzinoleamine, 2, 6- Diaminonaphthalene, 1,4-diaminonaphthalene, 1,8 diaminonaphthalene, 2,7 diaminonaphthalene,

 [0028] 3,3, -diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4 'diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,3'-diaminodiph Enyl sulfoxide, 3, 4'-diaminodiphenyl sulfoxide, 4, 4'-diaminodiphenyl sulfoxide, 3, 3'-diaminodiphenyl sulfone, 3, 4'-diaminodiphenyl sulfone, 4, 4'-diaminodiphenyl sulfone 3, 3'-Diaminobenzophenone, 3, 4'-Diaminobenzofenone, 4, 4'-Diaminobenzophenone, 3, 3'-Diaminodiphenylenemethane, 3, 4'-Diaminodiphenylmethane, 4, 4'-Diaminodiph Enylmethane, bis [4 — (4-aminophenoxy) phenyl] methane, 1, 1-bis [4— (4-aminophenoxy) phenol binole] ethane, 1, 2 bis [4 (4 aminophenoxy) pheneno] ethane, 1,1 bis [4 — (4 aminophenoxy) pheneno] propane, 1,2 bis [4— (4 aminophenoxy) pheneno]] propane, 1,3 bis [4 (4 aminophenoxy) phenol] propane, 2,2-bis [4-((4-aminophenoxy) phenol] propane,

 [0029] 1,1 bis [4 (4-aminophenoxy) phenyl] butane, 1,3 bis [4 (4-aminophenoxy) phenolin] butane, 1,4 bis [4 (4 (aminophenoxy) phene] Ninole] butane, 2, 2 bis [4 1 (4-aminominophen) phenine] butane, 2,3 bis [4 1 (4-aminophenoxy) phenyl] butane, 2— [4— (4 aminophenoxy) phenyl] 2 — [4— (4 aminophenoxy) 3 methylphenoxy] propane, 2, 2 bis [4— (4 aminophenoxy) 1 3 methylphenoxy] propane, 2 — [4 one (4 aminophenoxy) phenyl] -2— [ 4 One (4-aminophenoxy) 3,5 Dimethylphenol] propane, 2,2 bis [4— (4 Aminophenoxy) 3,5 Dimethylphenol] propane, 2,2 bis [4— (4 Aminophenoxy) ) Phenyl] -1, 1, 1, 3, 3, 3—Hexafluoro Propane,

[0030] 1,4 bis (3 aminophenoxy) benzene, 1,3 bis (3 aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, Bis [4- (4-aminophenoxy) phenol] ketone, Bis [4- (4-aminophenoxy) phenol] sulfide, Bis [4 (4-aminophenoxy) phenol] sulfoxide, Bis [4- (4-Aminophenoxy) phenone] sulfone, bis [4-((3-aminophenoxy) phene Ninole] ether, bis [4 (4-aminophenoxy) phenyl] ether, 1,3-bis [4 (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene 1, 4, 2-bis [4- (3-aminophenoxy) benzoyl] benzene, 4, 4, monobis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl Nore] propane, 1,3-bis [4 (3-aminophenoxy) phenyl] propane, 3,4'-diaminodiphenylsulfide,

 [0031] 2, 2 Bis [3— (3 Aminophenoxy) phenyl] — 1, 1, 1, 3, 3, 3 Hexafluoropropane, Bis [4— (3-Aminophenoxy) phenol] methane, 1 , 1 Bis [4- (3-aminophenoxy) phenyl] ethane, 1,2 Bis [4-((3-aminophenoxy) phenyl] ethane, Bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4, 4, 1-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4,1-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4 'bis [4 (4-amino-α, a dimethylenobenzyl) phenoxy] benzophenone, 4, 4'-bis [4- (4-amino-1-α, a-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} Ninore] sulfone, 1, 4—bis [4— ( 4-aminophenoxy) phenoxy α, α-dimethylbenzyl] benzene, 1,3-bis [4 (4-aminophenoxy) phenoxy-a, a-dimethylbenzyl] benzene, 1,3-bis [4 (4-amino-6) —Trifluoromethylphenoxy) α, α-Dimethylbenzyl] benzene, 1,3-bis [4 (4-amino-6-fluorophenoxy) -a, a-dimethylbenzenole] benzene, 1 , 3-bis [4- (4-amino-6-methylphenoxy) α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-cyanphenoxy) α, α dimethinolevendinore] benzene,

[0032] 3,3, -diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5 'diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxy Benzophenone, 3, 3'-diamino-4 phenoxybenzophenone, 4, 4'-diamino-5-phenoxyben zophenone, 3, 4'-diamino-4 phenoxybenzophenone, 3, 4'-diamino-5 ' — Phenoxybenzophenone, 3, 3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3, 4'-diamino- 4,5'-dibiphenoxybenzophenone, 3, 3, -diamino-4-biphenoxybenzophenone, 4, 4, -Diamino-5-biphenoxybenzophenone, 3, 4 '-Diamino-4-biphenoxyben zophenone, 3, 4' -Diamino-5 '-biphenoxybenzophenone, 1,3-bis (3-amino) — 4-phenoxybenzoino) benzene, 1,4-bis (3-amino-4-phenoloxybenzoino) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) benzene, 1, 4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoino) benzene, 1,4 bis (3-amino-4) -Biphenoxybenzoinole) Benzene, 1,3-bis (4-amino-5-biphenoxybenzoinole) benzene, 1,4-bis (4 amino-5-biphenoxybenzoyl) benzene, 2 , 6 bis [4- (4 amino 1 α, a-dimethylbenzyl ) Phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring in the aromatic diamine are fluorine atoms, alkyl groups having 1 to 3 carbon atoms, alkoxyl groups, cyano groups, alkyl groups or alkoxyl group hydrogen atoms. Examples thereof include aromatic diamines substituted with a fluorinated alkyl group having 1 to 3 carbon atoms substituted with a fluorine atom or an alkoxyl group.

 [0033] The molecule used in the present invention does not contain a chlorine atom! /, An aromatic tetracarboxylic acid (including tetracarboxylic acid, dianhydride, amide bond derivative, etc.) that can be preferably used. Specific examples of carboxylic acids include, but are not limited to, compounds represented by [Chemical 27] to [Chemical 50].

 [0034] [Chemical 27]

[0036] [化 29]

[0036] [Chemical 29]

[0040] [化 33]

[0040] [Chemical 33]

[0041] [Chemical 34]

 [0044] [Chemical 37]

[0045] [化 38]

[0045] [Chemical 38]

[0046] [Chemical 39]

[0047] [Chemical 40]

 [0048] [Chemical 41]

[0049] [Chemical 42]

 [0052] [Chemical 45]

[0053] [Chemical 46]

[0057] [Chemical 50]

In the present invention, one or more aromatic tetracarboxylic acids exemplified below may be used in combination with the aromatic tetracarboxylic acids. Preferably, it is less than 50 mol% of all tetracarboxylic acids (including tetracarboxylic acid and carboxylic acid derivatives), or less than 30 mol%, more preferably less than 20 mol%.

[0059] pyromellitic anhydride, 3, 3 ', 4, 4'-biphenyltetratetracarboxylic dianhydride, 2, 3 ,, 3, 4'-biphenyltetratetracarboxylic dianhydride, 2 , 2 ', 3, 3'-biphenyl tetratetracarboxylic dianhydride, 3, 3' 4, 4'-oxydiphenyl tetracarboxylic anhydride, benzophenone 3, 3 ', 4, 4'-tetracarboxylic Acid dianhydride, diphenyl sulfone 3, 3 ', 4, 4'-tetracarboxylic dianhydride, 4, 4' mono (2, 2 hexafluoroloy propylidene) diphthalic dianhydride, diphenyl melophene Dianhydride, 2, 2, 1 diphenoxy 1, 3, 3 ', 4, 4'-biphenyl tetratetracarboxylic dianhydride, 1, 2, 5, 6 naphthalene tetracarboxylic dianhydride, 2, 3, 6 , 7 Naphthalenetetracarboxylic dianhydride, 2, 3, 5, 6 Pyridinetetracarboxylic dianhydride, 1, 4, 5, 8 Naphthalenetetracarboxylic dianhydride, 3, 4, 9, 10 Perylenetetracarboxylic dianhydride, 4, 4 'Sulfodirudiphthalic dianhydride, 3, 3, 4, 4, 4 , -Tetraphenylsilane tetracarboxylic dianhydride, metaterfeline, 3, 3 ', 4, 4'-tetracarboxylic dianhydride, 3, 3', 4, 4'-diphenyl ether tetracarboxylic Acid dianhydride, 1,3-bis (3,4-dicarboxyphenyl) 1,1,3,3-tetramethyldisiloxane dianhydride, 1- (2,3-dicarboxyphenyl) mono 3— (3,4-dicarboxyphenyl) 1 1,1,3,3—tetramethyldisiloxane dianhydride, (trifluoromethyl) pyromellitic dianhydride, di (dianhydride, penta Fluoroetilpyromellitic dianhydride, bis {3,5-di (trifluoro Methyl) phenoxy} pyromellitic dianhydride, 2, 2 bis (3,4 dicarboxyphenyl) hexafluoropropane dianhydride, 5, 5, -bis (trifluoromethyl) -3, 3 ,, 4, 4'-tetracarboxybiphenyl dianhydride, 2, 2, 1, 5, 5, -tetrakis (trifluoromethyl) -3, 3 ,, 4, 4, 4-tetracarboxybiphenyl dianhydride, 5, 5,1bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxydiphenyl ether dianhydride, 5,5, bis (trifluoromethyl) 3,3', 4,4'-tetra Carboxybenzophenone dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} benzene dianhydride, bis {(tris (dicarboxyphenoxy) (trifluoromethyl) benzene dianhydride, Bis (dicarboxiphenoxy) bis (trifluoromethyl) E) Benzene dianhydride, bis (dicarboxyphenoxy) tetrakis (trifluoromethinole) benzene dianhydride, 2, 2 bis {(4 (3,4 dicanoloxyphenoxy) phenyl) Xafluoropropane dianhydride, bis {(trifluoronorlevoxyphenoxy) bis (trifluoromethyl) biphenyl dianhydride, bis {(trifluoromethylinore) dicarboxyphenoxy} diphenyl ether dianhydride, bis Hydrogen atoms on the aromatic ring in (dicarboxyphenoxy) bis (trifluoromethyl) biphenyl dianhydride, 2, 2 bis [4 ((4,4 dicarboxyphenoxy) phenyl] propane and the above aromatic tetracarboxylic acids A part or all of these are fluorine atoms, alkyl groups having 1 to 3 carbon atoms, alkoxyl groups, cyano groups, alkyl groups or alkoxy Some or all of the hydrogen atoms of the Le group aromatic tetracarboxylic acid substituted with an fluorinated alkyl group or alkoxyl group having 1 to 3 carbon atoms are exemplified by a fluorine atom.

These tetracarboxylic acids may be used alone or in combination of two or more. The polyimide of the present invention can be produced, for example, by polycondensation (polymerization) of the aromatic diamines and the aromatic tetracarboxylic acid (anhydride) to produce a polyamic acid, and imidizing the polyamic acid. Thus, polyimide can be obtained. The solvent used in the production of the polyamic acid is not particularly limited as long as it dissolves the raw material monomer and the resulting polyamic acid! /, But there is no particular limitation, but a polar organic solvent is preferred. 2-pyrrolidone, N-acetylyl 2-pyrrolidone, N, N dimethylformamide, N, N Examples thereof include talamides such as lumamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoric amide, ethyl acetate sorb acetate, diethylene glycol dimethyl ether, sulphophoran, halogenated phenols, and m-taresol. These solvents can be used alone or in combination. The amount of the solvent used is sufficient if it is sufficient to dissolve the monomer as a raw material. The specific amount used is that the mass power of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by mass, preferably The amount is 10-30% by mass.

[0061] In the present invention, a co-solvent may be used to azeotrope water. For example, force S including toluene, xylene and the like is not limited as long as water can be efficiently azeotroped.

 The conditions for the polymerization reaction for producing the polyamic acid (hereinafter, simply referred to as “polymerization reaction”) are as follows: after the production of polyamic acid, the conventional known conditions can be applied, followed by thermal imidization or chemical imidization. The two-stage polymerization, or the one-stage polymerization which is performed at once in an organic solvent until imidization is preferably used.

 Specific examples of the two-stage polymerization include stirring and / or mixing continuously in an organic solvent at a temperature range of 0 to 80 ° C. for 10 minutes to 30 hours. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of addition of both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic anhydrides to a solution of aromatic diamines.

[0062] On the other hand, the one-step polymerization is continuously carried out in a temperature range of 0 to 80 ° C for 10 minutes to 30 hours with stirring and / or mixing in an organic solvent, and then further performed at 100 to 300 ° C. The process is continued for 10 to 30 hours in the temperature range. If necessary, the polymerization reaction can be divided or the temperature can be raised or lowered. In this case, the order of addition of both reactants is not particularly limited, but it is preferable to add aromatic tetracarboxylic acid anhydrides to the solution of aromatic diamines. The polymerization reaction is preferably carried out while distilling off water together with the azeotropic solvent. Further, a ring-closing catalyst may be used. Specific examples of the ring-closing catalyst used in the present invention include aromatic carboxylic acids such as benzoic acid, o-benzoic acid, m-benzoic acid and p-benzoic acid, and aliphatic tertiary compounds such as trimethylamine and triethylamine. Grade amine, isoquinoline, pyridine, beta It is preferable to use at least one amine selected from a force S such as a heterocyclic tertiary amine such as picoline and a heterocyclic tertiary amine. The content of the ring-closing catalyst is preferably in the range in which the content (mol) of the ring-closing catalyst (mol) / the content (mol) of the precursor polyamic acid is 0.01 to 10;

 The mass of the polyamic acid obtained by the polymerization reaction or the polyamic acid or polyimide in the polyimide solution is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and the viscosity of the solution is a Brookfield viscometer According to the measurement according to the above (25 ° C.), the point of stability of the liquid feeding is also preferably 10 to 2000 Pa ′s, more preferably 100 to lOOOPa ′s.

 The reduced viscosity (7] sp / C) of the polyamic acid or polyimide in the present invention is not particularly limited, but is preferably 1. Odl / g or more, more preferably 2.0 dl / g or more.

[0063] Vacuum degassing during the polymerization reaction is effective for producing a good quality polyamic acid or polyimide organic solvent solution. Further, the polymerization may be controlled by adding a small amount of an end-capping agent to the aromatic diamine before the polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as anhydrous maleic acid. When maleic anhydride is used, the amount used is preferably from 0.00;! To 1.0 monole per mole of aromatic diamine.

 [0064] As an imidization method by high-temperature treatment, a conventionally known imidization reaction can be appropriately used. For example, using a polyamic acid solution that does not contain a ring-closing catalyst or a dehydrating agent, the imidization reaction proceeds by subjecting it to a heat treatment (so-called thermal ring-closing method), or a polyamic acid solution containing a ring-closing catalyst and a dehydrating agent. There can be mentioned a chemical ring closure method in which an imidization reaction is carried out by the action of the above ring closure catalyst and a dehydrating agent.

 The heating maximum temperature of the thermal ring closure method is exemplified by 100 to 500 ° C, preferably 200 to 480 ° C. If the maximum heating temperature is lower than this range, it is difficult to sufficiently close the ring, and if it is higher than this range, deterioration proceeds and the composite tends to become brittle. A more preferred embodiment includes a two-stage heat treatment in which treatment is performed at 150 to 250 ° C. for 3 to 20 minutes and then treatment at 350 to 500 ° C. for 3 to 20 minutes.

[0065] In the chemical ring closure method, the imidization reaction of the polyamic acid solution partially proceeds to provide self-supporting properties. After the polyimide precursor to be formed is formed, imidization can be performed completely by heating.

 In this case, the condition for partially proceeding with the imidization reaction is preferably a heat treatment at 100 to 200 ° C. for 3 to 20 minutes (3 minutes to 30 hours), in order to complete the imidation reaction. The condition is preferably a heat treatment for 3 to 20 minutes at 200 to 400 ° C.

 The timing for adding the ring-closing catalyst to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid, or may be added during or after the polymerization reaction. Specific examples of the ring-closing catalyst include aliphatic tertiary amines such as trimethylamine and triethylamine, and heterocyclic tertiary amines such as isoquinoline, pyridine, and betapicoline. At least one amine selected from tertiary amines is preferred. The amount of the ring-closing catalyst used per mole of polyamic acid is not particularly limited, but is preferably 0.01 to 10 moles.

 The timing of adding the dehydrating agent to the polyamic acid solution is not particularly limited, and may be added in advance before the polymerization reaction for obtaining the polyamic acid. Specific examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. Among them, acetic anhydride, benzoic anhydride, etc. Acids or mixtures thereof are preferred. The amount of the dehydrating agent used per mole of polyamic acid is not particularly limited, but is preferably 0.01 to 10 moles. When using a dehydrating agent, you can use acetylacetone and the like together! The polyimide in the present invention is preferably a polyimide having a linear expansion coefficient of 60 ppm / ° C or less and a skeleton represented by the structural formula [Chemical Formula 7]. Preferably, it is obtained by reacting 2,2'-bis (biphenyl) benzidine (a diamine having a [Chemical 7] skeleton) with tetracarboxylic dianhydride having a rigid structure such as pyromellitic acid. More preferred is [Chemical 5 ;! ] ~ ~ As shown in [Chemical formula 59] !, a polyimide obtained by reacting with a substituted aromatic tetracarboxylic dianhydride, especially 3,6-diphenylbiromellitic acid [Chemicals 51] is preferably used for tetracarboxylic dianhydride! /.

In the present invention, mixing other resins with the polyimide described above does not exclude this unless the dimensional stability and low linear expansion coefficient of the present invention are impaired! / It is preferable that 50% by mass or more is contained in the mixed resin.

 The birefringence of the polyimide is not particularly limited as long as it is 0.15 or less. The force S is preferably 0.10 or less. If the birefringence exceeds 0.15, the functionality as an optical component is likely to be impaired.

 The synthesis of 2,2′-bis (biphenyl) benzidine in the present invention was in accordance with the following document (Non-Patent Document 2).

 Non-Patent Document 2: Der— Jang Liaw, Macromolecules, 38, 4024 (2005)

[0067] The polyimide in the present invention is preferably a polyimide having a skeleton represented by the structural formula [Chemical Formula 8]. Rigidities such as 2,5 diphenylenol 1,4 phenyldiamine (diamine of [Chemical Formula 8]) and pyromellitic acid, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride It is a polyimide obtained by reacting with a tetracarboxylic dianhydride having a simple structure, and more preferably has a rigid and bulky substituent as shown in the above [Chemical Formula 51] to [Chemical Formula 59]. It is a polyimide obtained by reacting with an aromatic tetracarboxylic dianhydride. In particular, it is desirable to use [Chemical Formula 52] or [Chemical Formula 53] as a tetracarboxylic dianhydride. In the present invention, mixing other resins with the polyimide does not exclude this unless the low birefringence, heat resistance, and dimensional stability of the present invention are impaired, but the polyimide of the present invention is mixed. It is preferable to contain 50% by mass or more in the resin.

 The synthesis of 2,5 diphenyl-1,4 phenylenediamine in the present invention was in accordance with the following non-patent literature.

 Non-Patent Document 3: L. H. Klemm, J. Heterocyclic. Chem, 2, 140 (1965)

[0068] [Chemical 51]

[0069] [Chemical 52]

[0073] [Chemical 56]

 Chemicalization 59]

The birefringence of the polyimide is not particularly limited as long as it is 0.15 or less, and preferably S 0.05 or less. More preferably 0.03 or less, still more preferably 0.0 1 or less, particularly preferably 0.005 or less is desirable. If the birefringence exceeds 0.1, the functionality as an optical component is likely to be impaired.

 The linear expansion coefficient of the polyimide is not particularly limited as long as it is 70 ppm / ° C or less, but is preferably 50 ppm / ° C or less, more preferably 30 ppm / ° C or less, and even more preferably 15 ppm / ° C. ° C or less is preferred. When the linear expansion coefficient exceeds 70 ppm / ° C, distortion occurs between the polyimide and the substrate, and there is a high possibility that warpage and peeling will occur due to this distortion.

 [0078] In the present invention, various fillers may be added to the polyimide within a range that does not impair the properties of the optical material polyimide as an optical waveguide. Examples of such fillers include wear resistance improvers such as graphite, carborundum, keystone powder, molybdenum disulfide, and fluorine resins, reinforcing agents such as glass fibers and carbon fibers, antimony trioxide, and magnesium carbonate. Flame retardants such as calcium and calcium carbonate, electrical property improvers such as clay and my strength, tracking resistance improvers such as vest, silica and graphite, and acid resistance such as barium sulfate, silica and calcium metasilicate Heat conductivity improver such as iron powder, zinc powder, aluminum powder, copper powder, glass beads, glass spheres, talc, key algae, alumina, shirasu balun, hydrated alumina, metal oxide, colorant, etc. Can be mentioned.

 [0079] In the present invention, the polyimide obtained by the reaction may be reprecipitated from the reaction solution using an appropriate poor solvent. Examples of the poor solvent include acetone, methanol, ethanol, water, and the like. The poor solvent is not particularly limited as long as it can be reprecipitated efficiently. In addition, the solvent for removing the residual reaction solvent after reprecipitation is not particularly limited, but it is preferable to use the solvent used for reprecipitation.

[0080] In the present invention, the reaction solution may be used as a polyimide solution as it is, or the polyimide reprecipitated by the above-described method may be dissolved in a solvent again to obtain a polyimide solution. Good. In the latter case, there is no particular limitation as long as the polyimide can be dissolved efficiently, but examples include o-creso monore, m-creso monore, p-creso monore, N-methylo. Organic compounds such as 2-pyrrolidone, N-acetylyl 2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolatathone, sulfolane, halogenated phenols A solvent is mentioned. [0081] In the present invention, the means for mixing the polyimide and the organic solvent is not particularly limited. For example, a method of mixing and stirring using a normal stirring blade, a high-viscosity stirring blade, multi-axial extrusion, and the like. And a method using a static mixer or the like, and a method using a high viscosity mixing and dispersing machine such as a roll mill.

 [0082] The composition of the polyimide in the polyimide solution obtained in the present invention is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. in this case. Its viscosity is 0 · l to 2000 Pa-s as measured with a Brookfield viscometer, preferably;! To lOOOPa • s, which is preferable because stable processing is possible.

 [0083] In the present invention, the method of applying the polyimide solution onto the substrate is not particularly limited! /, For example, spin coating such as spin coating, doctor blade, applicator, comma coater For example, a method using a squeegee, a screen printing method, and the like.

 In the present invention, the drying temperature condition for removing the polyimide solution solvent applied on the substrate is 80 ° C or higher, preferably 150 ° C or higher, more preferably 180 ° C or higher. Is. If the drying temperature is too low, it takes time to evaporate the solvent, or sufficient drying is expected! If the drying temperature is high! /, Better, 1S too high, the film properties will deteriorate due to thermal deterioration, so it is better to keep the temperature below 500 ° C.

 [0084] The base material is preferably a base material that constitutes an electric / electronic component, a wiring board, or the like, but is not limited thereto. For example, an inorganic substrate such as a silicon wafer, a glass substrate, or a copper foil, a polyethylene terephthalate film And organic substrates such as polyimide films.

 Example

 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

 In addition, the evaluation method of the physical property in the following examples etc. is as follows.

 1. Reduced viscosity of polyamic acid and polyimide (7] sp / C)

 A solution dissolved in Ν-methyl-2-pyrrolidone so that the polymer concentration was 0.2 g / dl was measured at 25 ° C. with an Ubbelohde type viscosity tube.

(If the solvent used to prepare the polyamic acid solution is N, N-dimethylacetamide, N The polymer was dissolved and measured using N-dimethylacetamide. )

 2. Thickness of polyimide layer (film)

 The measurement was made using a micrometer (Millitron 1254D, manufactured by Finerfu).

[0086] 3. Average linear expansion coefficient of polyimide layer (film) from 30 ° C to 200 ° C

 For the polyimide layer (film) to be measured, measure the stretch rate / temperature at intervals of 30 ° C, 40 ° C, 40 ° C, 50 ° C, ... and 10 ° C under the following conditions. C, and calculate the average value of all measured values from 50 ° C to 200 ° C when the temperature falls as the average coefficient of linear expansion (CTE) /

 Device name: TMA4000S manufactured by MAC Science

 Sample length; 10mm

 Sample width: 2mm

 Temperature rise start temperature; 25 ° C

 Temperature rise end temperature; 400 ° C

 Heating rate: 5 ° C / min

 Atmosphere: Argon

[0087] 4. Birefringence measurement

 The polyimide layer (film) to be measured was placed on a glass substrate, the refractive index nTE, ηΤΜ in the TE and TM directions was measured under the following conditions, and the birefringence index Δη = η = -ηΤΕ was calculated.

 Device name: Metricon Prism Force Plastic Model 2010

 Measurement wavelength: 633nm

 Moh ； Dual Film

 [0088] 5. Measurement of glass transition point

 For the polyimide layer (film) to be measured, the glass transition point (Tg) was measured under the following conditions. The glass transition point mentioned here was calculated as the Inflection temperature in the analysis of the step-like curve.

 Device name: DSC2920 manufactured by Ti Instruments Co., Ltd.

 Sample amount: 10 ± 0.5mg

Temperature rise start temperature; room temperature Temperature rise end temperature: 450 ° C

 Heating rate: 10 ° C / min

 Atmosphere: Argon

 For polyimides with a rigid primary structure, the glass transition point may not be detected by the above DSC measurement. In that case, the inflection point in the above average linear expansion coefficient measurement was taken as the glass transition point. If there was no inflection point up to 400 ° C, the glass transition point was determined to be 400 ° C or higher.

[0089] 4. Propagation loss measurement

 Using the optional function of Metricon's Prism Force Plastic Model 2010, measurements were made by the scattering detection method. The scattering detection method uses an optical fiber as a probe, moves the tip approaching the waveguide while keeping the angle and the distance from the waveguide constant, and plots logP with respect to L. This is a measurement method for calculating propagation loss.

 Device name: Metricon Prism Force Plastic Model 2010

 Measurement wavelength: 633nm

 Measuring distance: 5cm

[0090] (Example 1)

In a dry nitrogen atmosphere, DPBPDA [Chemical Formula 37] (2, 2'-diphenylenole 3, 4, 3 ', 4'-biphenylenetetracarboxylic dianhydride) was added in an amount of 4.46 parts by mass and DAMBO (5-amino- 2- (p-aminomino) benzoxazolene) ² · 25 parts by mass were dissolved in m-taresol to give a 3% by mass solution. After stirring this at room temperature for 3 hours, isoquinoline is added as a catalyst, stirred at 200 ° C for 3 hours under a nitrogen stream, and cooled to room temperature to obtain a highly viscous solution. When this polyimide solution was reprecipitated in ethanol, a yellow fibrous polymer was obtained. After drying the polymer, which was dissolved in N- methyl-2-pyrrolidone, and 10 mass _^0/0 solution was applied to a clean silicon substrate, in a dry nitrogen atmosphere, a 15-minute 120 ° C, 350 ° By heating with C for 1 hour, a polyimide film with a thickness of 20 m was obtained. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured to find 14.7 ppm / ° C. The birefringence was Δ η = 0.1128 (ηΤΕ = 1. 7301, ηΤΜ = 1.6173). The glass transition point is a force that cannot be detected by DSC. On the other hand, no inflection point was found in the wrinkle measurement Therefore, the glass transition point was determined to be 400 ° C or higher.

[0091] (Example 2)

In a dry nitrogen atmosphere, DPBPDA [Chemical Formula 37] (2, 2'-diphenylenole 3, 4, 3 ', 4'-biphenylenetetracarboxylic dianhydride) was added in an amount of 4.46 parts by mass and TFMB (2, 2 'Bis (trifnoleolomethyl) ⁴ , ⁴ , diaminobiphenyl) 3 · 20 parts by mass was dissolved in m-taresol to give a 3% by mass solution. After stirring this at room temperature for 3 hours, isoquinoline is added as a catalyst, stirred at 200 ° C for 3 hours under a nitrogen stream, and cooled to room temperature to obtain a highly viscous solution. When this polyimide solution was reprecipitated in ethanol, a light yellow fibrous polymer was obtained. After drying the polymer, a polyimide film was obtained in the same manner as in Example 1. The film was peeled from the silicon substrate and the coefficient of linear expansion was measured to be 24.7 ppm / ° C. In addition, the DSC showed that the glass transition point was a force that could not be measured, and the resulting force was from the inflection point of the TMA to the glass transition temperature (up to 390 C. On the other hand, the birefringence index (up to Δ η = 0.0.676 (ηΤΕ = 1. 6452, ηΤΜ = 1. 5776).

[0092] (Example 3)

 In a dry nitrogen atmosphere, DPBPDA [Chemical Formula 37] (2, 2'-diphenylenole 3, 4, 3 ', 4'-biphenylenetetracarboxylic dianhydride) was added in an amount of 4-46 parts by mass and Fluorenediamine (9, 9 , Bis (4-aminophenyl) fluorene) 3 · 48 parts by mass was dissolved in m-taresol to give a 5% by mass solution. After stirring this at room temperature for 3 hours, isoquinoline is added as a catalyst, stirred at 200 ° C for 3 hours under a nitrogen stream, and cooled to room temperature to obtain a highly viscous solution. When this polyimide solution was reprecipitated in ethanol, a light yellow fibrous polymer was obtained. After drying the polymer, a polyimide film was obtained in the same manner as in Example 1. The film was peeled off from the silicon substrate and the coefficient of linear expansion was measured to be 39.5 ppm / ° C. Moreover, the glass transition temperature was 360 from the inflection point of the force TMA, which could not be measured by DSC. C. On the other hand, the birefringence was Δη = 0.0146 (ηΤΕ = 1.6822, ηΤΜ = 1.676).

[0093] (Example 4)

In a dry nitrogen atmosphere, DPBPDA [Chemical Formula 37] (2,2'-diphenylenoyl 3, 4, 3 ', 4'-biphenylenetetracarboxylic dianhydride) 3.57 parts by mass, BPDA (3,4 , 3, 4, bihue Polyimide in the same manner as in Example 1 except that 0 · 56 parts by mass of dienetetracarboxylic dianhydride) and DAMBO (5 amino-2- (ρ-aminophenyl) benzoxazole) 2. 25 parts by mass were used. A film was obtained. The film was peeled from the silicon substrate, and the linear expansion coefficient was measured and found to be 10.5 ppm / ° C. Since the glass transition point could not be detected by DSC and the inflection point was not observed in the TMA measurement, the glass transition point was determined to be 400 ° C or higher. On the other hand, the birefringence was Δη = 0.1430 (ηΤΕ = 1. 7541, ηΤΜ = 1.61111).

 [Example 5]

 In a dry nitrogen atmosphere, DPBPDA [Chemical Formula 37] (2, 2'-diphenyl 3, 4, 3 ', 4'-biphenylene tetracarboxylic dianhydride) was added in an amount of 4.46 parts by mass and DAMBO (5 Mino 1— (paminophenenole) benzoxazonole) 1.13 mass ^ Fluorenediamin e (9, 9 'bis (4-aminophenyl) fluorene) 1. Example 1 except that 74 parts by mass were used A polyimide film was obtained in the same manner. This film was peeled off from the silicon substrate, and the coefficient of linear expansion was measured to be 20. lppm / ° C. The glass transition point could not be detected by DSC, and no inflection point was observed by TMA measurement. On the other hand, the birefringence was Δη = 0.0430 (ηΤΕ = 1.7082, ηΤΜ = 1.6652).

 [Example 6]

 In a dry nitrogen atmosphere, DPPMDA [Chemical 8] (1,4 diphenylpyromellitic acid dianhydride) 3.70 parts by mass and DAMBO (5 amino-2- (ρaminophenyl) benzoxazole) 2.25 parts by mass Was dissolved in m-taresole to give a 3% by mass solution. Thereafter, a polyimide film was obtained in the same manner as in Example 1. The linear expansion coefficient was 25. Oppm / ° C. The birefringence was Δη = 0.1481 (ηΤΕ = 1. 7174, ηΤΜ = 1. 5693). The glass transition point is a force that cannot be detected by DSC. On the other hand, it was judged that the glass transition point was 400 ° C or higher because the inflection point was not observed in the TMA measurement.

[Example 7]

In a dry nitrogen atmosphere, DPPMDA [Chemical Formula 8] (1,4 diphenylpyromellitic acid dianhydride) 3.70 parts by mass and TFMB (2,2, -bis (trifluoromethyl) —4, 4 'Jia Minobifueniru) 3. 20 parts by weight were dissolved in m- Tarezoru and a solution of 4 wt _^0/0. Thereafter, a polyimide film was obtained in the same manner as in Example 1. The linear expansion coefficient was 19.8 ppm / ° C. The glass transition point could not be detected by DSC. On the other hand, the TMA measurement showed that the inflection point was not seen, and the glass transition point was determined to be 400 ° C or higher. On the other hand, the birefringence was Δ η = 0.0505 (ηΤΕ = 1.6098, ηΤΜ = 1.5593).

[Example 8]

In a dry nitrogen atmosphere, DPOBPDA [Chemical 21] (2, 2'-Diphenyl 3, 4, 3 ', 4'- Biphenyl tetracarboxylic dianhydride) 4.78 parts by mass and DAMBO (5 Amino-2 (paminophenol) benzoxazonole ( ² · 25 parts by mass) was dissolved in m-taresol to give a 10% by mass solution. Thereafter, a polyimide film was obtained in the same manner as in Example 1. The linear expansion coefficient was 14.5 ppm / ° C. The birefringence was Δ η = 0 · 0781 (ηΤΕ = 1.7260, ηΤΜ = 1.6479). The glass transition point could not be detected by DSC. On the other hand, the TMA measurement showed that the inflection point was not observed, and the glass transition point was judged to be 400 ° C or higher.

[Example 9]

 In a dry nitrogen atmosphere, DPOBPDA [Chemical Formula 21] (2, 2'-diphenyl 3, 4, 3 ', 4'- biphenyltetracarboxylic dianhydride) was added in 4 · 78 parts by mass and TFMB (2 , 2'-bis (trifluoromethyl) 4, 4, diaminobiphenyl) 3 · 20 parts by mass was dissolved in m-taresol to give a 10% by mass solution. Thereafter, a polyimide film was obtained in the same manner as in Example 1. The linear expansion coefficient was 26. lppm / ° C. The glass transition point could not be detected by DSC. On the other hand, the TMA measurement showed that the inflection point was not observed, and the glass transition point was judged to be 400 ° C or higher. On the other hand, the birefringence was Δη = 0.04414 (ηΤΕ = 1.6338, ηΤΜ = 1.5924).

[0099] (Example 10)

In a dry nitrogen atmosphere, DPOBPDA [Chemical 21] (2, 2'-diphenyl 3, 4, 3 ', 4'- biphenylene tetracarboxylic dianhydride) in 4 · 78 parts by mass and Fluorenediamine (9 , 9, bis (4aminophenenole) fluorene) 3 · 48 parts by mass was dissolved in m-taresol to give a 10% by mass solution. Thereafter, a polyimide film was obtained in the same manner as in Example 1. Linear expansion The tonicity factor was 38. Oppm / ° C. The glass transition temperature could not be measured by DSC. From the inflection point of force S and TMA, the glass transition temperature was 350 ° C. On the other hand, the birefringence was Δη = 0.0047 (ηΤΕ = 1.6727, ηΤΜ = 1.6680).

[0100] (Comparative Example 1)

 In a dry nitrogen atmosphere, 2 · 94 parts by mass of BPDA (3, 4, 3 ', 4'-biphenylenetetracarboxylic dianhydride) and 1 · 08 parts by mass of PDA (p-phenylenediamine) N —Dissolved in methyl-2-pyrrolidone to give a 12% by mass solution. When this was stirred for 15 hours at room temperature, a highly viscous yellow polyamic acid solution was obtained. This polyamic acid solution is applied onto a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a polyimide film with a thickness of 20 μm. It was. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured to find 15. lppm / ° C. The birefringence was Δη = 0.2631 (ηΤΕ = 1.8665, ηΤΜ = 1.6034). The glass transition point could not be detected by DSC, and the TMA measurement showed no inflection point. Therefore, the glass transition point was determined to be 400 ° C or higher.

[0101] (Comparative Example 2)

 In a dry nitrogen atmosphere, 2 · 94 parts by mass of BPDA (3, 4, 3 ', 4'-biphenylene ditetracarboxylic dianhydride) and DAMBO (5-amino-2- (p-aminophenyl) benzoxazole) 2. A polyimide film having a thickness of 20 m was obtained in the same manner as Comparative Example 1 except that 25 parts by mass was used. The linear expansion coefficient of this film was 8. lppm / ° C. The birefringence was Δη = 0.2815 (ηΤΕ = 1.8484, ηΤΜ = 1.6033). Since the glass transition point could not be detected by DSC and the inflection point was not observed in the wrinkle measurement, the glass transition point was determined to be 400 ° C or higher.

[0102] (Comparative Example 3)

In a dry nitrogen atmosphere, 2-94 parts by mass of BPDA (3, 4, 3 ', 4'-biphenylenditetracarboxylic dianhydride) and Fluorenediamine (9,9'-bis (4-aminominophenyl) fluorene) 3. 48 parts by mass was dissolved in m-talesole to make a 10% by mass solution. After stirring this at room temperature for 3 hours, isoquinoline is added as a catalyst, stirred at 200 ° C for 3 hours under a nitrogen stream, and cooled to room temperature to obtain a highly viscous solution. This polyimide solution in ethanol When re-precipitated, a yellow fibrous polymer was obtained. After drying the polymer, a polyimide film was obtained in the same manner as in Example 1. The film was peeled from the silicon substrate and the coefficient of linear expansion was measured. As a result, it was 41. Oppm / ° C and the glass transition point was 380 ° C. On the other hand, the birefringence was Δ η = 0.0387 (ηΤΕ = 1.6910, ηΤΜ = 1.6523).

[0103] (Comparative Example 4)

 In a dry nitrogen atmosphere, 3.58 parts by mass of DSDA (diphenylsulfone-3, 4, 3 ', 4'-tetracarboxylic dianhydride) and ODA (4, 4'-diaminodiphenyl ether) 2. A polyimide film was obtained in the same manner as in Comparative Example 3 except that 00 parts by mass was used. This finenome was peeled from the silicon substrate, and the coefficient of linear expansion was measured to be 64.5 ppm / ° C and the glass transition point was 280. C. On the other hand, the birefringence was Δ η = 0 · 0072 (ηΤΕ = 1.6692, ηΤΜ = 1.6620).

 [Example 10]

 In a dry nitrogen atmosphere, add 3, 6 diphenylpyrrolomellitic anhydride (lmmol, 0.370 3g) and 2,2 'bis (biphenyl) benzidine (lmmol, 0.4886g) to m cresol. Dissolved to give a 4% by weight solution. After stirring this at room temperature for 2 hours, isoquinoline was added as a catalyst, stirred at 200 ° C for 30 minutes under a nitrogen stream, and when this polyimide solution was reprecipitated in 2-propanol, a yellow powdery polymer was formed. Obtained. The polymer obtained was washed with 2-propanol and dried. The reduced viscosity of the polymer was 1.38. The polymer is dissolved in N-methyl-2-pyrrolidone by heating to form a 10% by mass solution, applied onto a clean silicon substrate, and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour. As a result, a 6.5 m thick polyimide film was obtained. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured to be 3.7 ppm / ° C. The birefringence of this film was Δη = 0.05533 (ηΤΕ = 1.7055, ηΤΜ = 1.6522), and the propagation loss was 2.7 dB / cm. The glass transition point could not be detected by DSC, and no inflection point was found in the TMA measurement, so the glass transition point was determined to be 400 ° C or higher.

 [Example 12]

In a dry nitrogen atmosphere, pyromellitic anhydride (lmmol, 0.2942g) and 2,2'bis (biphenyl) benzidine (lmmol, 0.4886g) were dissolved in N-methyl-2-pyrrolidone. 20% by mass solution. When this is stirred for 24 hours at room temperature in a nitrogen atmosphere, a highly viscous solution is obtained. The reduced viscosity of the obtained solution was 1.17. The polymer solution was applied on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a 8.2-m thick polyimide film. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured. As a result, it was 20.8 ppm / ° C. The birefringence of this film was Δ η = 0.0267 (ηΤΕ = 1.6846, ηΤΜ = 1. 6579), and the propagation loss was 2.9 dB / cm. The glass transition point could not be detected by DSC, and no inflection point was found by TMA measurement, so the glass transition point was determined to be 400 ° C or higher.

 [Example 13]

 In a dry nitrogen atmosphere, 3, 4, 3 ', 4'-biphenyltetracarboxylic anhydride (lmmol, 0.2942g) and 2,2, -bis (biphenyl) benzidine (lmmol, 0.4886g) Was dissolved in m-talesol to give a 10% by mass solution. After stirring this for 2 hours at room temperature, isoquinoline is added as a catalyst, stirring at 200 ° C for 3 hours under a nitrogen stream, and then cooling to room temperature gives a highly viscous solution. When this polyimide solution was reprecipitated in 2-propanol, a light yellow fibrous polymer was obtained. The polymer obtained was washed with 2-propanol and dried. The reduced viscosity of the polymer was: Dissolve the polymer in N-methyl-2-pyrrolidone to make an 8% by weight solution, apply it on a clean silicon substrate, and heat in a dry nitrogen atmosphere at 120 ° C for 15 minutes and at 350 ° C for 1 hour. As a result, a polyimide film having a thickness of 7.4 m was obtained. The film was peeled from the silicon substrate and the coefficient of linear expansion was measured. C. Further, the birefringence of this film was Δη = 0.03341 (ηΤΕ = 1. 7195, ηΤΜ = 1.6854), and the propagation loss was 2.3 dB / cm. The glass transition point could not be detected by DSC, and no inflection point was found by TMA measurement. Therefore, the glass transition point was determined to be 400 ° C or higher.

 [Example 14]

In a reaction vessel, 3, 3 ', 4, 4'-biphenyltetracarboxylic dianhydride (lmmol, 0.294 2g), 2, 2, monobis (biphenyl) 1, 1, 1, monodiphenyl 1 4 , 4, monodiisocyanate (lm mol, 0.5406g) and potassium salt of FUJI 匕 potassium lOOmg, dissolved in 10g of N-methylolene-2-pyrrolidone, then stirred at 80 ° C to 150 ° C under nitrogen flow for 8 By reacting for hours As a result, a transparent and viscous polyamideimide solution was obtained. The polymer solution was applied on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a polyimide film having a thickness of 10.6 mm. The film was peeled from the silicon substrate and the coefficient of linear expansion was measured to find 18.6 ppm / ° C. Further, the birefringence of this film was Δη = 0.0276 (ηΤΕ = 1. 7163, ηΤΜ = 1.6887), and the propagation loss was 2.2 dB / cm. Since the glass transition point could not be detected by DSC and the inflection point was not seen in TMA measurement, the glass transition point was judged to be 400 ° C or higher.

[0108] (Comparative Example 5)

In a dry nitrogen atmosphere, 4, 4 '-(2,2'-hexafluoroisopropylidene) diphthalanol dianhydride (lmmol, 0.444g) and 2,2'-bis (biphenol) benzidine (lm mol, 0. 4886g) was dissolved in m cresol one Honoré was 10 mass _^0/0 solution. This is stirred for 3 hours at room temperature, then isoquinoline is added as a catalyst, stirred for 3 hours at 200 ° C under a nitrogen stream, and cooled to room temperature to obtain a highly viscous solution. When this polyimide solution was reprecipitated in 2-propanol, a white fibrous polymer was obtained. After drying the polymer, a polyimide film having a film thickness of 26.8 m was obtained in the same manner as in Example 1, and the coefficient of linear expansion was measured to be 62.3 ppm / ° C. The glass transition point was 285 ° C. On the other hand, the birefringence (up to Δ η = 0.006 (ηΤΕ = 1.6361, ηΤΜ = 1.6301)) and propagation loss (up to 1.2 dB / cm).

[0109] (Comparative Example 6)

In a dry nitrogen atmosphere, dissolved pyromellitic anhydride (2. 181 g) and 1, 3-bis (4 Aminofu enoxy) benzene (2 · 923g) in dimethyl § Seth amide was 12 mass _^0/0 solution . When this is stirred for 24 hours at room temperature in a nitrogen atmosphere, a highly viscous solution is obtained. Using this polyamic acid solution, a polyimide film with a film thickness of 15.2 m was obtained in the same manner as in Example 2. The coefficient of linear expansion was measured to be 51.4 ppm / ° C and the glass transition point was 330 ° C. It was hot. On the other hand, the birefringence was Δ η = 0.1307 (ηΤΕ = 1. 7380, ηΤΜ = 1. 6073), and the propagation loss was 2.8 dB / cm.

[0110] (Comparative Example 7)

2, 2'-Diphenyl 3, 4, 3 ', 4'-tetracarboxylic anhydride in dry nitrogen atmosphere Objects (10 mmol, 2. 942 g) was dissolved and 5-amino-2- (4 Aminofueniru) Benzookisazo le (10 mmol, 2. 253 g) and dimethyl § Seth amide was 10 mass _^0/0 solution. When this is stirred at room temperature for 96 hours in a nitrogen atmosphere, a highly viscous solution is obtained. The reduced viscosity of the obtained solution was 0.44. The polymer solution was applied on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a polyimide film having a thickness of 13. mm. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured to find 8. lppm / ° C. The birefringence of this film was Δη = 0.6022 (ηΤΕ = 1.88765, ηΤΜ = 1.1633), and the propagation loss was 4.9 dB / cm. The glass transition point could not be detected by DSC, and no inflection point was observed by TMA measurement, so the glass transition point was determined to be 400 ° C or higher.

[0111] (Comparative Example 8)

 In a dry nitrogen atmosphere, pyromellitic anhydride (10 mmol, 2. 181 g) and 5 amino-2- (4-aminophenyl) benzoxazole (10 mmol, 2.253 g) are dissolved in dimethylacetamide to give a 10% by mass solution. It was. When this is stirred at room temperature for 24 hours in a nitrogen atmosphere, a highly viscous solution is obtained. The reduced viscosity of the obtained solution was 3.1. A polymer solution was coated on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and at 350 ° C for 1 hour to obtain a 9.4 m thick polyimide film. . The film was peeled from the silicon substrate and the coefficient of linear expansion was measured and found to be 0.8 ppm / ° C. The birefringence of this film was Δη = 0.2524 (ηΤΕ = 1.8471, ηΤΜ = 1.5947), and the propagation loss was 5.2 dB / cm. The glass transition point could not be detected by DSC, and the inflection point was not observed in TMA measurement, so the glass transition point was determined to be 400 ° C or higher.

Yes

 [0112] (Example 15)

2, 2'-Diphenoxy 3, 3 ', 4, 4'-Biphenyltetracarboxylic dianhydride (lmmol, 0.4784g) and 2,5 Diphenenole 1, 4 Phenyl diamamine in dry nitrogen atmosphere (lmmol, 0. 2603g) was dissolved in dimethyl § Seth amide was 20 wt _^0/0 solution. When this is stirred at room temperature for 96 hours in a nitrogen atmosphere, a highly viscous solution is obtained. The reduced viscosity of the obtained solution was 0.465. Apply the polymer solution onto a clean silicon substrate. A polyimide film having a thickness of 20.O ^ m was obtained by coating and heating in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour. This film was peeled off from the silicon substrate, and the coefficient of linear expansion was measured to be 55.7 ppm / ° C. In addition, the birefringence of this film was Δη = 0.0.00076 (η486 = 1.6486, ηΤΜ = 1.6478), and the propagation loss was 2.6 dB / cm. The glass transition point could not be detected by DSC, and no inflection point was found in the TMA measurement, so the glass transition point was determined to be 400 ° C or higher.

 [0113] (Example 16)

 In a dry nitrogen atmosphere, 3, 3 ', 4, 4'-biphenyltetracarboxylic dianhydride (lmmol, 0.2942g) and 2,5 diphenylinol 1,4 phenylenediamine (lmmol, 0 260 3g) was dissolved in dimethylacetamide to give a 20% by weight solution. When this is stirred at room temperature for 6 hours in a nitrogen atmosphere, a gel polymer is obtained. The reduced viscosity of the obtained polymer was 0.75. When the gel polymer is heated at 120 ° C for 30 seconds, a polymer solution is obtained. This polymer solution is quickly applied onto a clean silicon substrate, 120 in a dry nitrogen atmosphere. 15 minutes at C, 350. A 6.0-m-thick polyimide Finolem was obtained by heating the temple for 1 day. The film was peeled from the silicon substrate and the coefficient of linear expansion was measured. C. The birefringence of this film was Δη = 0.00301 (ηΤΕ = 1.66 834, ηΤΜ = 1.66533), and the propagation loss was 2.9 dB / cm. The glass transition point could not be detected by DSC, and the TMA measurement showed no inflection point. Therefore, the glass transition point was determined to be 400 ° C or higher.

 [0114] (Example 17)

2, 2'-Diphenoxy 3, 3 ', 4, 4'-Biphenyltetracarboxylic acid dihydrate (lmmol, 0.4784g), 2, 5 By adding cyanate (lmmol, 0.3123g) and potassium salt of futsui potassium lOOmg and dissolving in 10g of N-methinole-2-pyrrolidone, the mixture was allowed to react at 80 ° C to 150 ° C for 8 hours with stirring under a nitrogen stream. A clear and viscous polyamideimide solution was obtained. The polymer solution was applied on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a 15.2 mm thick polyimide film. This film was peeled off from the silicon substrate, and the coefficient of linear expansion was measured. As a result, it was 55.7 ppm / ° C. Also, the double bending of this film As a result, Δ η = 0. 0060 (ηΤΕ = 1. 6535, ηΤΜ = 1. 6475), and the propagation loss was 2.8 dB / cm 2. The glass transition point could not be detected by DSC, and no inflection point was found in the TMA measurement. Therefore, the glass transition point was determined to be 400 ° C or higher.

[0115] (Comparative Example 9)

 In a dry nitrogen atmosphere, 3, 4, 3 ', 4'-benzophenone tetracarboxylic anhydride (10 mmol, 3. 222 g) and 5 amino-2- (4 aminopheninole) benzoxazole (10 mmol, 2.253 g) was dissolved in dimethylacetamide to give a 10% by weight solution. When this is stirred at room temperature for 24 hours in a nitrogen atmosphere, a highly viscous solution is obtained. The reduced viscosity of the obtained solution was 2.5. The polymer solution was applied on a clean silicon substrate and heated in a dry nitrogen atmosphere at 120 ° C for 15 minutes and 350 ° C for 1 hour to obtain a polyimide film having a thickness of 20.6 m. The film was peeled from the silicon substrate, and the coefficient of linear expansion was measured to find 23.7 ppm / ° C. This film had a birefringence of Δη = 0.2320 (ηΤΕ = 1.8417, ηΤΜ = 1.6097), and a propagation loss of 3. OdB / cm. The glass transition point could not be detected by DSC, and no inflection point was found by TMA measurement. Therefore, the glass transition point was determined to be 400 ° C or higher.

[0116] (Comparative Example 10)

In a dry nitrogen atmosphere, dissolved pyromellitic anhydride (2. 181 g) and 1, 3-bis (4 Aminofu enoxy) benzene (2 · 923g) in dimethyl § Seth amide was 12 mass _^0/0 solution . When this is stirred for 24 hours at room temperature in a nitrogen atmosphere, a highly viscous solution is obtained. Using this polyamic acid solution, a polyimide film with a film thickness of 15.2 m was obtained in the same manner as in Example 2. The coefficient of linear expansion was measured to be 51.4 ppm / ° C and the glass transition point was 330 ° C. It was hot. On the other hand, the birefringence was Δ η = 0.1307 (ηΤΕ = 1. 7380, ηΤΜ = 1. 6073), and the propagation loss was 2.8 dB / cm.

 Industrial applicability

[0117] Since the polyimide of the present invention has a small linear expansion coefficient and a small difference from the linear expansion coefficient of a glass substrate or a key substrate, a clad layer or a core layer made of such a polyimide on these substrates. Even when the substrate is formed, the substrate is not curled and the substrate and the optical waveguide are not easily separated from each other, and the conductor circuit is insulated from the composite circuit board in which the conductor circuit and the optical waveguide are mixed. Insufficient defects in Au-Sn solder In 300 ° C or higher, polyimide is softened and deformed due to softening, etc., and malfunction is not caused. Also, the birefringence is small, so the functionality as an optical component is impaired. It is a polyimide that has characteristics such as no dimensional stability, low linear expansion coefficient, optical isotropy, heat resistance, light transmission characteristics, and insulation sustainability, and is useful for optical materials, particularly optical waveguides.

 Semiconductor mounting technology can be used as it is for optical waveguide production, and it is possible to produce highly reliable optical waveguides with little misalignment and warping at low cost, which is expected to make a significant contribution to the industry. Is done.

Claims

The scope of the claims  [1] A polyimide having no chlorine atom in the molecule, the polyimide having a glass transition point of 300 ° C or more, a birefringence of 0.15 or less, and a linear expansion coefficient of 70 ppm / ° C or less. Characteristic polyimide.  [2] The polyimide according to claim 1, wherein the polyimide has a glass transition point of 320 ° C. or higher and a linear expansion coefficient of 40 ppm / ° C. or lower. [3] The polyimide according to claim 2, wherein the molecule does not contain a chlorine atom! /, And the aromatic tetracarboxylic acid includes an aromatic tetracarboxylic acid having a skeleton of the following [Chemical ;!] to [Chemical 3] .  [Chemical 1]

(In [Chemical Formula 1] to [Chemical Formula 3], [Chemical Formula 1] shows two aspects of the phenyl skeleton, [Chemical Formula 2] shows two aspects of the biphenyl skeleton, and [Chemical Formula 3] shows three aspects of the naphthyl skeleton. , X;! To X6 represent a monovalent hydrocarbon aromatic group (phenyl, biphenyl, naphthyl), a monovalent aromatic ether group (phenoxy, biphenoxy, naphthoxy), hydrogen, and each unit (skeleton) ) At least one of them is a monovalent hydrocarbon aromatic group and / or a monovalent aromatic ether group, and the other bonding part represents a carboxylic acid bonding part. [4] The polyimide according to claim 2 or 31 /, wherein the aromatic diamine includes an aromatic diamine having a skeleton of [Chemical Formula 4] to [Chemical Formula 6] below.

 (In [Chemical 4] to [Chemical 6], in [Chemical 4], the two aspects of the phenyl skeleton are [Chemical 5] shows two aspects of the biphenyl skeleton, [Chemical 6] shows five aspects of the naphthyl skeleton, and X;! To X8 are monovalent hydrocarbon aromatic groups (phenyl, biphenyl, naphthyl). , Monovalent aromatic ether group (phenoxy, biphenoxy, naphthoxy), hydrogen, and at least one of each unit (skeleton) is a monovalent hydrocarbon aromatic group and / or monovalent aromatic ether group Yes, and the other binding part indicates an amine binding part. )  5. The polyimide according to claim 1, wherein the polyimide has a linear expansion coefficient of 60 ppm / ° C. or less, and the polyimide structure includes the following structural formula [Chemical Formula 7].  [Chemical 7]

6. The polyimide according to claim 5, wherein the birefringence of the polyimide is 0.1 or less.  [7] The polyimide structure contains a diamine skeleton represented by the following structural formula [Chemical Formula 8] The polyimide in any one of 1-4.  [Chemical 8]

 8. The polyimide according to claim 7, wherein the birefringence of the polyimide is 0.05 or less.  An optical waveguide using the polyimide described in 1-8.