JP2008169393A - Polyimide for optical part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide for optical parts that are used as optical parts such as optical wave guides optical filters, and light transmission films, having characteristic values, particularly a constant optical transmission loss. <P>SOLUTION: A tetracarboxylic dianhydride having a purity of ≥95 mol% and a diamine having a purity of ≥95 mol%, at least one of which is a fluorine-containing compound, are reacted to manufacture the polyimide for optical parts excluding wholly fluorinated polyimides. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing polyimide used for optical parts such as an optical waveguide, an optical filter, and a light transmission film.

Polyimide has excellent heat resistance among organic materials and has the characteristics of being resistant to various organic solvents, so it is used for semiconductor devices and circuit forming substrates that require high-temperature manufacturing processes. It has been. In addition, this feature is used for optical parts that require heat resistance. In order to use polyimide for an optical component, it is necessary to improve optical characteristics, and as such a method, a method using a polyimide containing a fluorine atom as shown in Patent Document 1 is known. .
Polyimide used for optical components is generally a polyimide precursor solution that is a polyimide precursor solution or a polyimide solution in which a polyimide that has been imidized from a polyamic acid solution is dissolved in an organic solvent, such as spin coating or casting, It is formed by thermosetting this.
The polyamic acid solution, which is a polyimide precursor solution, is generally obtained by a synthesis process in which an acid dianhydride monomer and a diamine monomer are reacted and polymerized in an organic solvent as raw materials.

The characteristics of the polyimide formed by such a method are affected by the state of the polyimide precursor solution and the curing conditions of the film. Among the various properties, the optical properties important for optical components vary particularly greatly. By controlling the molecular weight of the polymer in the polyimide precursor solution, birefringence can be controlled, or the type of organic solvent used in the solvent can be changed. The refractive index and the optical transmission loss can be changed, and the refractive index and the optical transmission loss can be controlled to some extent by the curing temperature, time, atmosphere and curing device of the film.
However, the polyimide precursor solution has a problem that the characteristic value, in particular, the value of optical transmission loss is not constant every time it is synthesized, and sometimes shows a large value.
JP-A-3-72528

  The invention according to claim 1 provides a method for producing a polyimide for optical parts, which makes it possible to stably produce a polyimide for optical parts having a constant characteristic value, in particular, a value of optical transmission loss, stably with a high yield. is there.

  The present invention relates to a method for producing a polyimide for optical parts, characterized by reacting a tetracarboxylic dianhydride having a purity of 95 mol% or more with a diamine having a purity of 95 mol% or more.

  The method for producing a polyimide for optical parts according to claim 1 makes it possible to stably produce a polyimide for optical parts having a constant characteristic value, in particular, a value of optical transmission loss, with a high yield.

The polyimide for optical components of the present invention can be obtained by imide ring closure of a polyimide precursor by a conventional method. The polyimide precursor is synthesized by reacting a diamine with tetracarboxylic dianhydride using a polar organic solvent such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, γ-butyrolactone, and dimethyl sulfoxide as a solvent. The
The proportion of diamine and tetracarboxylic dianhydride used at this time is preferably 0.95 to 1.05 mol of tetracarboxylic dianhydride with respect to 1 mol of diamine, from the viewpoint of increasing the molecular weight, More preferably, it is 1 mol.
The reaction temperature at this time is usually 0 to 50 ° C., and the reaction time is usually in the range of 0.5 to 50 hours. The synthesized polyimide precursor solution can be filtered under pressure at a pressure of 0.1 to 10 atm with a filter having a hole diameter of 0.2 to 20 μm to remove foreign matters mixed during the synthesis.

The organic solvent used as the solvent preferably has a purity of 96 mol% or more, more preferably 99 mol% or more, in order to prevent contamination by impurities and to suppress reaction suppression due to impurities such as water.
Thus, the weight average molecular weight (GPC measurement, standard polystyrene conversion) of the synthesized polyimide precursor is preferably 10,000 to 1,000,000 from the viewpoint of strength and handleability, and 100,000 to More preferably, it is 400,000.

  In the present invention, the purity of tetracarboxylic dianhydride and diamine used as raw materials must be 95% by weight or more, preferably 98% by mole or more, more preferably 99% by mole or more. preferable. When the purity is less than 95% by weight, it is impossible to stably produce polyimide for optical components having a constant characteristic value, particularly, a value of optical transmission loss. The purity of tetracarboxylic dianhydride and diamine used as raw materials affects the optical transmission loss of the formed polyimide. If the purity is low, impurities remain in the polyimide film and the chromophore is replaced by heating during film formation. The optical transmission loss increases due to the formation of a group, and if the purity is high, the purity of the formed polyimide increases and decreases to near the limit value of the theoretical optical transmission loss.

The impurities contained in tetracarboxylic dianhydride and diamine used as raw materials are trash, isomers having different amino group bonding positions, alkali metals such as lithium, sodium and potassium, noble metals such as platinum, Examples include compounds having monoamines and nitro groups. In tetracarboxylic dianhydrides, dust, isomers having different bonding positions of carboxyl groups, alkali metals such as lithium, sodium and potassium, noble metals such as platinum, Non-anhydride tetracarboxylic acid, tetracarboxylic acid that should be fluorinated but not fluorinated, tricarboxylic acid, dicarboxylic acid, monocarboxylic acid and the like can be mentioned.
Examples of methods for measuring the purity of tetracarboxylic dianhydride and diamine include differential scanning calorimetry (DSC) measurement, mass spectrum, nuclear magnetic resonance (NMR) measurement, liquid chromatography, and gas chromatography.

Further, as a method for increasing the purity of tetracarboxylic dianhydride, there are recrystallization using an organic solvent such as acetic anhydride, and as a method for increasing the purity of diamine, an organic solvent such as n-butanol and ethyl alcohol is used. There are recrystallization using, vacuum distillation and the like.
Although there is no restriction | limiting in particular in the kind of tetracarboxylic dianhydride and diamine used by this invention, From the point which improves transparency, the compound containing a fluorine is used for at least one of tetracarboxylic dianhydride and diamine. It is preferable to use it.

  Examples of the tetracarboxylic dianhydride containing fluorine include (trifluoromethyl) pyromellitic dianhydride, di (trifluoromethyl) pyromellitic dianhydride, di (heptafluoropropyl) pyromellitic dianhydride , Pentafluoroethylpyromellitic dianhydride, bis {3,5-di (trifluoromethyl) phenoxy} pyromellitic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane Dianhydride, 5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxybiphenyl dianhydride, 2,2'-5,5'-tetrakis (trifluoromethyl)- 3,3 ', 4,4'-tetracarboxybiphenyl dianhydride, 5,5'-bis (trifluoromethyl) -3,3', 4,4'-tetracar Xydiphenyl ether dianhydride, 5,5'-bis (trifluoromethyl) -3,3 ', 4,4'-tetracarboxybenzophenone dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} benzene dianhydride Bis {(trifluoromethyl) dicarboxyphenoxy} (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) bis (trifluoromethyl) Benzene dianhydride, bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) benzene dianhydride, 2,2-bis {(4- (3,4-dicarboxyphenoxy) phenyl} hexafluoropropane dianhydride, bis {(Trifluoromethyl) dicarboxyphenoxy} Phenyl dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} bis (trifluoromethyl) biphenyl dianhydride, bis {(trifluoromethyl) dicarboxyphenoxy} diphenyl ether dianhydride, bis (dicarboxyphenoxy) bis (Trifluoromethyl) biphenyl dianhydride etc. are mentioned.

  Examples of the diamine containing fluorine include 4- (1H, 1H, 11H-eicosafluoroundecanoxy) -1,3-diaminobenzene, 4- (1H, 1H-perfluoro-1-butanoxy) -1, 3-diaminobenzene, 4- (1H, 1H-perfluoro-1-heptanoxy) -1,3-diaminobenzene, 4- (1H, 1H-perfluoro-1-octanoxy) -1,3-diaminobenzene, 4 -Pentafluorophenoxy-1,3-diaminobenzene, 4- (2,3,5,6-tetrafluorophenoxy) -1,3-diaminobenzene, 4- (4-fluorophenoxy) -1,3-diaminobenzene 4- (1H, 1H, 2H, 2H-perfluoro-1-hexanoxy) -1,3-diaminobenzene, 4- (1H, 1H, 2H, 2H- -Fluoro-1-dodecanoxy) -1,3-diaminobenzene, (2,5) -diaminobenzotrifluoride, bis (trifluoromethyl) phenylenediamine, diaminotetra (trifluoromethyl) benzene, diamino (pentafluoroethyl) benzene 2,5-diamino (perfluorohexyl) benzene, 2,5-diamino (perfluorobutyl) benzene, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'- Bis (trifluoromethyl) -4,4'-diaminobiphenyl, octafluorobenzidine, 4,4'-diaminodiphenyl ether, 2,2-bis (p-aminophenyl) hexafluoropropane, 1,3-bis (anilino) Hexafluoropropane, 1,4-bis (anilino) Kutafluorobutane, 1,5-bis (anilino) decafluoropentane, 1,7-bis (anilino) tetradecafluoroheptane, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 3 , 3'-bis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 3,3 ', 5,5'-tetrakis (trifluoromethyl) -4,4'-diaminodiphenyl ether, 3,3'-bis (Trifluoromethyl) -4,4'-diaminobenzophenone, 4,4'-diamino-p-terphenyl, 1,4-bis (p-aminophenyl) benzene, p-bis (4-amino-2-tri Fluoromethylphenoxy) benzene, bis (aminophenoxy) bis (trifluoromethyl) benzene, bis (aminophenoxy) Tetrakis (trifluoromethyl) benzene, 2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- (3-aminophenoxy) phenyl} hexafluoropropane, 2, 2-bis {4- (2-aminophenoxy) phenyl} hexafluoropropane, 2,2-bis {4- (4-aminophenoxy) -3,5-dimethylphenyl} hexafluoropropane, 2,2-bis { 4- (4-aminophenoxy) -3,5-ditrifluoromethylphenyl} hexafluoropropane, 4,4′-bis (4-amino-2-trifluoromethylphenoxy) biphenyl, 4,4′-bis (4 -Amino-3-trifluoromethylphenoxy) biphenyl, 4,4'-bis (4-amino-2-trifluoromethyl) Phenoxy) diphenylsulfone, 4,4'-bis (3-amino-5-trifluoromethylphenoxy) diphenylsulfone, 2,2-bis {4- (4-amino-3-trifluoromethylphenoxy) phenyl} hexafluoro Propane, bis {(trifluoromethyl) aminophenoxy} biphenyl, bis [{(trifluoromethyl) aminophenoxy} phenyl] hexafluoropropane, bis {2-[(aminophenoxy) phenyl] hexafluoroisopropyl} benzene, etc. It is done.

  Examples of the tetracarboxylic dianhydride containing no fluorine include p-terphenyl-3,4,3 ″, 4 ″ -tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4. , 4'-benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-biphenyl ether tetracarboxylic dianhydride, 1 , 2,5,6-naphthalenetetracarboxylic 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'-sulfonyldiphthalic dianhydride, 3,3 ', 4,4 '-Tetraphenylsilante Lacarboxylic acid dianhydride, meta-terphenyl-3,3 ″, 4,4 ″ -tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride, 1,3- Bis (3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldisiloxane dianhydride, 1- (2,3-dicarboxyphenyl) -3- (3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldisiloxane dianhydride and the like. In order to obtain a polyamideimide resin, chlorotrimellitic anhydride or the like is usually used.

Examples of the diamine not containing fluorine include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, benzine, methanephenylenediamine, P-phenylenediamine, 2,2-bis- (4-aminophenoxyphenyl) propane, 1,5-naphthalenediamine, 2,6-naphthalenediamine, bis- (4-aminophenoxyphenyl) sulfone, bis- (4-amino) Phenoxyphenyl) sulfide, bis- (4-aminophenoxyphenyl) biphenyl, 1,4-bis- (4-aminophenoxy) benzene, 1,3-bis- (4-aminophenoxy) benzene, 3,4'-diamino Diphenyl ether, 3,3'-dimethyl 4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether-3-sulfonamide, 3,4'-diaminodiphenyl ether-4-sulfonamide, 3, 4,4'-diaminodiphenyl ether-3'-sulfonamide, 3,3'-diaminodiphenyl ether-4-sulfonamide, 4,4'-diaminodiphenylmethane-3-sulfonamide, 3,4'-diaminodiphenylmethane-4-sulfone Amides, 3,4'-diaminodiphenylmethane-3'-sulfonamide, 3,3'-diaminodiphenylmethane-4-sulfonamide, 4,4'-diaminodiphenylsulfone-3-sulfonamide, 3,4'-diaminodiphenyl Sulfone-4-sulfonamide, 3, 4 -Diaminodiphenyl sulfone-3'-sulfonamide, 3,3'-diaminodiphenyl sulfone-4-sulfonamide, 4,4'-diaminodiphenyl sulfide-3-sulfonamide, 3,4'-diaminodiphenyl sulfide-4- Sulfonamide, 3,3'-diaminodiphenyl sulfide-4-sulfonamide, 3,4'-diaminodiphenyl sulfide-3'-sulfonamide, 1,4-diaminobenzene-2-sulfonamide, 4,4'-diamino Diphenyl ether-3-carbonamide, 3,4'-diaminodiphenyl ether-4-carbonamide, 3,4'-diaminodiphenyl ether-3'-carbonamide, 3,3'-diaminodiphenyl ether-4-carbonamide, 4,4 '-Diaminodipheny Lumethane-3-carbonamide, 3,4'-diaminodiphenylmethane-4-carbonamide, 3,4'-diaminodiphenylmethane-3'-carbonamide, 3,3'-diaminodiphenylmethane-4-carbonamide, 4,4 '-Diaminodiphenylsulfone-3-carbonamide, 3,4'-diaminodiphenylsulfone-4-carbonamide, 3,4'-diaminodiphenylsulfone-3'-carbonamide, 3,3'-diaminodiphenylsulfone-4 '-Carbonamide, 4,4'-diaminodiphenyl sulfide-3-carbonamide, 3,4'-diaminodiphenyl sulfide-4-carbonamide, 3,3'-diaminodiphenyl sulfide-4-carbonamide, 3,4 '-Diaminodiphenyl sulfide-3 - sulfonamides, 1,4-diaminobenzene-2-carboxylic amide.
The above-mentioned tetracarboxylic dianhydrides and diamines are used alone or in combination of two or more.

This polyimide precursor solution is applied to a semiconductor substrate such as silicon or gallium arsenide, or an optical substrate such as quartz or glass by a spin coating method, a printing method, or the like, and 150 to 400 by a heating device such as a hot plate or an oven. The polyimide film for optical parts of the present invention can be formed by ring-closing the imide at a temperature of ° C., drying and curing. Further, these films are patterned by a method such as wet etching, dry etching, or laser application, if necessary, and formed into a predetermined shape to become an optical component.
Examples of optical components include lenses, optical waveguides, optical splitters, optical multiplexers, optical switching devices, optical modulators, optical filters, wavelength dividers, optical amplifiers, optical attenuators, wavelength converters, optical circuits, and the like. .

Example 1
A polyimide was formed using 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanoic acid dianhydride (6FDA) as tetracarboxylic dianhydride and paraphenylenediamine (PPD) as a diamine as raw materials. The optical transmission loss was measured.
6FDA having a purity of 94.3 mol% which had not been recrystallized was recrystallized using acetic anhydride to obtain a high purity monomer. Further, 93.8 mol% of PPD which had not been recrystallized was recrystallized using butanol to obtain a high purity monomer. The purity of these high-purity monomers was 99.5 mol% for 6FDA and 99.0 mol% for PPD, respectively. The purity of the monomer was measured by using DuPont's 9900 Computer / Thermal Analyzer System; Version 6.0 apparatus installed with DuPont's DSC DYNAMIC CALORIMETRIC PURITY DATA ANALYSIS PROGRAM; Version 1.0.

The synthesis was conducted by dissolving 5.88 g of PPD having a purity of 99.0 mol% in 170.0 g of N, N-dimethylacetamide having a purity of 99.9 mol% as a solvent in a 0.5 liter flat bottom flask. 99.5 mol% 6FDA (24.12 g) was added, and the mixture was stirred at room temperature in a nitrogen atmosphere for 10 hours to obtain a polyimide precursor solution having a viscosity of about 20 Pa · s.
Next, the precursor solution is applied onto a quartz wafer having a diameter of 4 inches by spin coating, and then in an oven at 100 ° C. for 3 minutes, then at 200 ° C. for 30 minutes, and then at 350 ° C. for 60 minutes in air. The imide was ring-closed by heating, dried and cured to form a polyimide film having a thickness of about 4 μm.
The optical transmission loss is measured by a light scattering method in which TM mode light is incident on a film through a prism by a polarizing filter using a semiconductor laser having a working wavelength of 830 nm, and light loss is calculated from the distance from the prism and the intensity of scattered light. Measured with
As a result, it was confirmed that the optical transmission loss was 0.5 dB / cm in both the TE mode and the TM mode and was good for optical parts.

Comparative Example 1
A polyimide precursor solution was synthesized in the same manner as in Example 1, using 93.8 mol% pure PPD that had not been recrystallized, and using the same raw materials as in Example 1 for 6FDA and N, N-dimethylacetamide. . The viscosity of this precursor solution was 3.8 Pa · s.
When this polyimide precursor solution was evaluated by the same method as in Example 1, the optical transmission loss was inferior at 2.3 dB / cm in both the TE and TM modes.

Claims (3)

  A fully fluorinated polyimide produced by reacting a tetracarboxylic dianhydride having a purity of 95 mol% or more with a diamine having a purity of 95 mol% or more and using a compound containing fluorine in at least one of the tetracarboxylic dianhydride and the diamine. Other polyimide for optical parts.   The polyimide for optical parts according to claim 1, wherein the purity of tetracarboxylic dianhydride and diamine is both 98 mol% or more.   2. The polyimide for optical parts according to claim 1, wherein the purity of tetracarboxylic dianhydride and diamine is 99 mol% or more.