JP2005206782A - Polyamic acid and polyimide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamic acid and polyimide without having an absorption in the ultraviolet light region, having high light transmittance and excellent in solubility in an organic solvent. <P>SOLUTION: This polyamic acid can be obtained from a tetracarboxylic acid dianhydride of a specific structure, having an aromatic ring and alicyclic ring structure with a diamine, and the polyimide is obtained from the polyamic acid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel polyamic acid obtained from a novel alicyclic tetracarboxylic dianhydride and a novel polyimide obtained therefrom.

Polyimide is used as a raw material for various industrial parts by utilizing its excellent mechanical strength, heat resistance, insulation, and solvent resistance, and it is also used as a curing agent for epoxy resin by utilizing reactivity. Furthermore, in recent years, it is used as a liquid crystal display element, an electronic material such as a protective material in a semiconductor, an insulating material, an optical communication material such as an optical waveguide material, and a liquid crystal alignment film.
However, typical wholly aromatic polyimides (for example, polyimides composed of ring-opening polyaddition reaction of pyromellitic acid and 4,4'-diaminodiphenyl ether) are dark amber, and therefore require high transparency. Problems arise in certain applications.
Further, since the aromatic ring is continuously present in the main chain, the absorption of light in the ultraviolet region is large, which may cause a problem when used for an optical functional member.
Further, since wholly aromatic polyimides are extremely insoluble in organic solvents, in some cases, polyamic acid as a precursor thereof is actually dissolved in a specific organic solvent and heated to cause a dehydrating imide ring-closing reaction. However, for example, as seen in the relationship between polyimide film formation and color filters in liquid crystal display devices, depending on the temperature and time required for this process, the function of other members used in combination with the polyimide may be adversely affected. There is.

As a means for solving the above problems, a polyamic acid is produced using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic dianhydride monomer, followed by a dehydrating imide ring-closing reaction to produce a polyimide having low colorability. Has been proposed.
However, alicyclic tetracarboxylic dianhydride monomers proposed in these technologies are compounds that require an ene reaction that generally has a problem in yield after the Diels-Alder reaction (for example, Patent Documents 1 to 4). 2), or a compound that is difficult to obtain easily due to a more complex structure (see, for example, Patent Documents 3 to 5). Therefore, these proposals are problematic in terms of cost. In addition, there is a potential danger of contamination. Further, the tetracarboxylic dianhydride is a compound having a relatively low melting point, and sufficient heat resistance cannot be obtained for the obtained polyimide. A tetracarboxylic dianhydride monomer having a tricyclo ring structure obtained from 1 mol of 1,1-diphenylethylene and 2 mol of maleic anhydride has also been proposed, but the 1-position formed by Diels-Alder reaction is also proposed. Carbon-carbon unsaturated bonds may decompose due to reverse Diels-Alder reaction at high temperatures. (For example, refer to Patent Documents 1 to 6 and Non-Patent Document 1.)
Japanese Patent Laid-Open No. 9-71650 JP-A-2002-338686 JP-A-6-136120 JP 2001-48874 A JP 2003-96070 A JP 9-2111467 A WNEmmerling et al, European Polymer Journal, Vol.13, p179-184

  In order to solve this problem, in addition to UV absorption, which is a characteristic when tetracarboxylic dianhydride is used as a monomer of polyimide, in addition to solubility in organic solvents, it has a high melting point and is a manufacturing process. To find a tetracarboxylic dianhydride that can be easily obtained in high yield, is easy to purify, has a high purity, and has an appropriate reactivity as a constituent monomer for polyamic acid and polyimide. is required.

  The first of the present invention is a polyamic obtained by reacting at least one of tetracarboxylic dianhydrides represented by the following general formulas (1) and (2) with a diamine represented by the following general formula (3): It is about acid.

  In the general formulas (1) and (2), R1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms. m and n are arbitrary integers of 0 to 5 independent of each other. When m + n is plural, plural R2s may be the same or different from each other.

  In the general formula (3), R3 represents a divalent organic group.

  In the second aspect of the present invention, at least one of tetracarboxylic dianhydrides represented by the first general formulas (1) and (2) of the present invention and a tetracarboxylic acid represented by the following general formula (4) The present invention relates to a polyamic acid obtained by reacting a dianhydride and a diamine represented by the following general formula (3).

  In General Formula (4), R1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms. m and n are arbitrary integers of 0 to 5 independent of each other. When m + n is plural, plural R2s may be the same or different from each other.

  A third aspect of the present invention relates to a polyimide obtained by dehydrating and ring-closing the polyamic acid according to the first or second aspect of the present invention.

  The present invention uses a novel alicyclic tetracarboxylic dianhydride having a specific structure obtained with high purity as a monomer, has no absorption in the ultraviolet region, has high light transmittance, and is soluble in organic solvents. Can be obtained. Since it is excellent in solubility in an organic solvent, it is easy to form a film by spin coating or the like, and it is possible to obtain a polyimide that is particularly excellent in moldability to a liquid crystal alignment film used in a liquid crystal display device. Moreover, the polyimide which is excellent in adhesiveness with a metal or an epoxy resin and can be used for various flexible circuit boards (including TAB, COF, etc.) can be obtained.

A polyimide obtained by dehydrating and ring-closing a polyamic acid obtained by reacting a tetracarboxylic dianhydride containing general formula (1) or (2) as an essential component with a diamine represented by general formula (3) The following excellent characteristics are derived from the structure of the alicyclic tetracarboxylic dianhydride represented by the general formulas (1) and (2) contained as a constituent material.
(1) Since the part which comprises the principal chain in alicyclic tetracarboxylic dianhydride is a tricyclo ring structure, the heat resistance of a polyimide is not reduced significantly.
(2) The structure of the alicyclic tetracarboxylic dianhydride is asymmetrical, and further includes an aromatic ring or a cyclohexane ring as a side chain, so that flexibility is imparted to the polyimide molecule and light transmittance is high. .
(3) Since the alicyclic tetracarboxylic dianhydride has an asymmetric structure and further contains an aromatic ring or a cyclohexane ring as a side chain, flexibility is imparted to the polyimide molecule, and the toughness of the coating film molded product Is expensive.
(4) Since the alicyclic tetracarboxylic dianhydride is produced through a mild and free side reaction route, the impurity concentration in the polyimide is low.
(5) Since the carbon / carbon double bond produced by the Diels-Alder reaction is hydrogenated, the decomposition due to the reverse Diels-Alder reaction in a high temperature environment is suppressed.

Hereinafter, the present invention will be described in detail.
The polyamic acid and polyimide of the present invention are obtained from at least one of tetracarboxylic dianhydrides represented by general formulas (1) and (2) and a diamine represented by general formula (3). Alternatively, the polyamic acid and the polyimide of the present invention include at least one of tetracarboxylic dianhydrides represented by general formulas (1) and (2) and a tetracarboxylic dianhydride represented by general formula (4). And a diamine represented by the general formula (3). The tetracarboxylic dianhydride represented by the general formulas (1) and (2) is obtained by reacting 1 mol of the compound represented by the general formula (5) with 2 mol of the compound represented by the general formula (6). It is obtained by hydrogenating the tetracarboxylic dianhydride represented by the general formula (4) obtained in this way. (See Non-Patent Document 1.)

  In General Formulas (5) and (6), R1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms. m and n are arbitrary integers of 0 to 5 independent of each other. When m + n is plural, plural R2s may be the same or different from each other.

Specific examples of the compound represented by the general formula (5) include 1,1-diphenylethylene, 1,1-di (methylphenyl) ethylene, 1-phenyl-1-methylphenylethylene, 1,1-diphenylpropene. 1,1-di (methylphenyl) propene, 1-phenyl-1-methylphenylpropene, and the like.
Specific examples of the compound represented by the general formula (6) include maleic anhydride, citraconic anhydride (3-methylmaleic anhydride), 3-ethylmaleic anhydride, 3,4-dimethylmaleic anhydride, 3-chloro. Maleic anhydride, 3,4-dimethylmaleic anhydride, etc. are mentioned.

  1 mol of the compound of the general formula (5) and 2 mol of the compound of the general formula (6) react with each other through the route shown in FIG. 1 to produce a tetracarboxylic dianhydride of the general formula (4). Conceivable. For the progress of the reaction, a catalyst is not particularly required, and it can be obtained by using a solvent as appropriate, mixing them and heating and stirring them. When the solvent is used, the reaction temperature is generally near the boiling point of the solvent, but can be performed at 50 to 200 ° C. More preferably, it is 60-150 degreeC. Although the reaction time is determined from the relationship with the reaction temperature, it is usually preferably in the range of 0.1 to 20 hours.

Hereinafter, the reaction route will be described with reference to FIG.
The compound of the general formula (5) and the general formula (6) forms a charge transfer complex due to the difference in the electron density of the carbon / carbon double bond.
Therefore, it is preferable that the substituents present in the compounds of the general formula (5) and the general formula (6) do not reduce the difference in electron density between the carbon / carbon double bonds of the two. That is, it is not preferred that a substituent other than the aromatic ring of the compound of the general formula (5) has a strong electron-withdrawing substituent, and a strong electron-donating substituent is present on the carbon of the compound of the general formula (6). It is not preferable to exist. Furthermore, the presence of a substituent having a steric hindrance effect is also undesirable.

Therefore, it is preferable that at least one of R1 in the general formula (5) and R1 in the general formula (6) is a hydrogen atom. Further, when each of R1 and R2 is an alkyl group, it preferably has 10 or less carbon atoms, more preferably 5 or less carbon atoms, and particularly preferably a methyl group or a propyl group.
Furthermore, about the compound of General formula (5), it is preferable to set it as m + n <= 4, and m + n <= 2 is especially preferable. Therefore, the most preferable compound represented by the general formula (5) is 1,1-diphenylethylene, and the most preferable compound represented by the general formula (6) is maleic anhydride.

  The charge transfer complex formed from the general formula (5) and the general formula (6) becomes a six-membered ring (cyclohexadiene ring) by an intramolecular cyclization reaction, and the cyclohexadiene part in the six-membered ring compound and the raw material compound It is considered that the carbon / carbon double bond portion of the general formula (6) generates the compound of the general formula (4) via the Diels-Alder reaction. Since the carbon / carbon double bond produced by the Diels-Alder reaction may be decomposed by the reverse Diels-Alder reaction in a high-temperature environment, hydrogenation is performed by a conventional method using a known reduction method, etc. A tetracarboxylic dianhydride represented by the general formula (1) as a single bond, and further a tetracarboxylic dianhydride represented by the general formula (2) by nuclear hydrogenation of the aromatic ring of the side chain; To do.

In the catalytic reduction method, palladium, ruthenium, rhodium, platinum, nickel, cobalt, etc. are used as a metal catalyst, and the hydrogen pressure is in a range from normal pressure to 10 MPa (100 kg / cm 2) in a solvent, and the temperature is 0 to 150. It can be performed in the range of ° C.
More specifically, when the tetracarboxylic dianhydride represented by the general formula (1) is obtained in a high yield, the hydrogen pressure is set in the range of 1 MPa to 5 MPa in the presence of the palladium-based catalyst, and the temperature is set to room temperature to 50-50. The catalytic reduction is preferably performed in the range of 5 ° C. for 5 to 20 hours. When the tetracarboxylic dianhydride represented by the general formula (2) is obtained in a high yield, the hydrogen pressure is set to 5 MPa in the presence of a palladium catalyst. The catalytic reduction may be performed in the range of 8 MPa and the temperature in the range of 50 to 100 ° C. for 5 to 20 hours.

  The tetracarboxylic dianhydrides represented by the general formulas (1), (2), and (4) have special reaction conditions compared to the tetracarboxylic dianhydrides used in conventional alicyclic polyimides. An optical functional member that can be obtained without a by-product in a reaction under mild conditions compared to an ene reaction, etc., without producing any by-products, and requires a high purity. It exhibits extremely excellent properties as a monomer for producing polyimides used in it. Among these, the tetracarboxylic dianhydrides represented by the general formulas (1) and (2) are required to have high heat resistance or long-term stability because there is no reverse Diels-Alder reaction even in a high temperature environment. It is excellent as a constituent monomer for polyimide.

  In the tetracarboxylic dianhydride represented by the general formulas (1), (2), and (4) according to the present invention, two carboxylic dianhydride groups are arranged asymmetrically in a tricyclo ring structure. And a side chain (for example, a benzene ring if n = 0). The present inventors consider that the basic structure is greatly involved in the heat resistance of polyamic acid and polyimide, the solubility in organic solvents, and the provision of toughness.

  In addition to the above basic characteristics, if you want better heat resistance and affinity with aromatic materials, tetracarboxylic dianhydride represented by general formula (1), better transparency and dissolution When desired, the tetracarboxylic dianhydride represented by the general formula (2) is used singly, but when these properties are desired in a balanced manner, they may be mixed and used. In addition, the tetracarboxylic dianhydride represented by the general formula (4) may be used in combination when a chemical modification or a cross-linking reaction is desired, or when thermal decomposition that does not leave a large amount of residue at 300 ° C. or higher is desired. preferable.

  In addition, in order to obtain the polyamic acid and the polyimide according to the present invention, a ring-opening polyaddition reaction or a ring-closing reaction is carried out in the tetracarboxylic dianhydride represented by the general formulas (1), (2), (4). It is preferable not to contain a substituent that causes steric hindrance with respect to progress, and among the general formulas (1), (2), and (4), a tetracarboxylic dianhydride synthesized from 1,1-diphenylethylene and maleic anhydride Things are preferred. Needless to say, other known tetracarboxylic acid anhydrides used as components of polyimide can be used in combination as long as the effects of the present invention are not impaired.

There is no restriction | limiting in particular as a diamine compound represented by General formula (3), What is necessary is just a diamine compound known as a polyimide constituent monomer. R3 preferably has 6 to 18 carbon atoms, and more preferably has an aromatic ring.
Preferred examples include p-phenylenediamine, 4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4′-diaminodiphenyl ether, 4,4 ′-(p-phenylene) Isopropylidene) bisaniline, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2′-bis [4- ( 4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2 -Trifluoromethyl) phenoxy] -octafluorobiphenyl, etc., particularly preferably p-phenylenedia And 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenyl ether.

  The polyamic acid of the present invention comprises a tetracarboxylic dianhydride represented by general formulas (1), (2), and (4) and a diamine compound represented by general formula (3), for example, It can be synthesized by addition reaction.

The preferred use ratio when the polyamic acid is synthesized with the tetracarboxylic dianhydride represented by the general formulas (1), (2) and (4) and the diamine compound represented by the general formula (3) is as described above. The acid anhydride group of the tetracarboxylic dianhydride with respect to 1 equivalent of the amino group contained in the diamine compound is within a range of 0.2 to 4 equivalents. When it is desired to obtain a polyamic acid having a high degree of polymerization, the range is 0.8 to 1.2 equivalents.
By the above method, a polyamic acid having a logarithmic viscosity in the range of 0.05 to 10 can be obtained. The value of logarithmic viscosity is as follows: logarithmic viscosity = [ln (solution viscosity / solvent viscosity)] / at 30 ° C. for a solution having a concentration of 0.5 g / 100 ml using N-methyl-2-pyrrolidone as a solvent. Determined by [Solution concentration].

  The synthetic reaction of polyamic acid is usually carried out in an organic solvent under a temperature condition of 0 to 150 ° C, preferably 0 to 100 ° C. Here, the organic solvent is not particularly limited as long as it can dissolve the synthesized polyamic acid. Examples of solvents include non-protons such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, and hexamethylphosphortriamide. Examples thereof include phenolic solvents such as system polar solvents, m-cresol, phenol, and halogenated phenol.

Subsequently, this reaction solution and a poor solvent for polyamic acid are mixed to obtain a precipitate, and this precipitate is dried under reduced pressure to obtain a polyamic acid. Further, the polyamic acid can be purified by dissolving the polyamic acid again in an organic solvent and precipitating with a poor solvent once or several times.
Examples of poor solvents include water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and cyclohexanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl acetate and ethyl acetate, diethyl And ethers such as ether and ethylene glycol methyl ether.

  According to a known method, the polyimide according to the present invention is heated to remove the low molecular weight compound generated during the imidation reaction as it is or in an organic solvent while removing the low molecular weight compound from the system. Synthesis). The reaction temperature in heating is 50 to 300 ° C, preferably 100 to 200 ° C. When the reaction temperature is less than 50 ° C., the imidization reaction does not proceed sufficiently, and when the reaction temperature exceeds 300 ° C., the molecular weight of the resulting polyimide may decrease.

  Also, the polyimide according to the present invention can be synthesized by adding a dehydrating agent and an imidization catalyst to the polyamic acid solution. Examples of the dehydrating agent include acid anhydrides such as acetic anhydride and propionic anhydride. Examples of imidation catalysts include tertiary amines such as triethylamine, pyridine, collidine and the like. Moreover, the polyimide of this invention can be refine | purified by performing operation similar to the purification method of polyamic acid with respect to the reaction solution obtained in this way.

  The polyimide according to the present invention is derived from the structure of the alicyclic tetracarboxylic dianhydride represented by the general formulas (1) and (2) contained as its constituent materials, and is a conventional alicyclic tetracarboxylic acid. Compared with a polyimide containing acid dianhydride, it is characterized by having the following excellent characteristics, and is a very balanced polyimide.

  Some polyimide main chains obtained from conventional alicyclic tetracarboxylic dianhydrides are introduced with free-rotatable carbon / carbon bonds in tetracarboxylic dianhydrides. Although heat resistance could not be obtained, in the polyimide according to the present invention, the main chain portion constituting the tetracarboxylic dianhydride is a tricyclo ring structure, and the reverse Diels-Alder reaction is suppressed, Good heat resistance. (See TGA analysis below.)

  Since the structure of the alicyclic tetracarboxylic dianhydride of the present invention is asymmetric and further contains an aromatic ring or a cyclohexane ring as a side chain, the polyimide molecule is given flexibility and has high light transmittance. (Refer to the visual observation of the solution described later and the UV spectrum.)

  Conventional alicyclic tetracarboxylic dianhydride monomers having a bicyclo ring structure usually have a symmetric structure. However, the tetracarboxylic dianhydride according to the present invention has an asymmetric structure, and the asymmetric structure provides a polyimide molecule. Toughness is imparted by flexibility, and a tough coating film is obtained.

  Since the alicyclic tetracarboxylic dianhydride of the present invention is produced through a mild and free side reaction route, the impurity concentration of the polyimide molecule is low. As is clear from the description of Examples below, crystals having a sharp melting point can be obtained by purification by recrystallization.

EXAMPLES Hereinafter, although an Example is given and the content of this invention is demonstrated concretely, this invention is not limited to these.

<Synthesis of tetracarboxylic dianhydride>
Into a 20 ml capacity eggplant-shaped flask, 5.10 g of 1,1-diphenylethylene and 2.78 g of maleic anhydride (molar ratio 1: 1) were added, and after degassing dissolved oxygen for 10 minutes, 140 oil baths were added.
The mixture was kept at ℃ and stirred for 5 hours. The temperature of the reaction system was 106 ° C. After completion of the reaction, toluene was added to the flask, and the deposited precipitate was collected by filtration. The weight of the filtrate was 3.65 g.
In this synthesis example, 1,1-diphenylethylene is charged as a reaction raw material, and at the same time, the excess functions as a solvent. The yield of this synthesis example is 68% based on 2.51 g of 1,1-diphenylethylene and 2.78 g of maleic anhydride (molar ratio 1: 2).
(Melting point measurement by DSC analysis)
The compound recrystallized from ethyl acetate showed a clear endothermic peak at 290 ° C. under the temperature rising condition at 20 ° C./min.

<Determining the structure of tetracarboxylic dianhydride>
(Mass spectrum)
As a result of mass spectrum, the molecular weight of the product was 376.
(IR spectrum measurement)
700 cm-1 to 740 cm-1: 1 substituted aromatic attribute peak 760 cm-1 to 860 cm-1: carbon / carbon double bond attribute peak 1780 cm-1 to 1880 cm-1: carboxylic acid anhydride attribute peak (1H NMR spectrum measurement)
1H NMR spectrum (DMSO-d6)
2.55 (m, 2H), 2.75 (m, 2H): hydrogen on carbon adjacent to the carbonyl group 3.50 to 3.60 (m, 2H)
3.70 (t, 1H): hydrogen on carbon at the cyclohexene ring and cyclohexadiene ring bond 3.80 (m, 2H): methine hydrogen in cyclohexene 6.00 (t, 1H), 6.25 ( t, 1H): hydrogen at carbon-carbon double bond 7.20 (d, 2H), 7.35 (t, 1H), 7.45 (t, 2H):
From the above analysis results, the chemical structure of the product is a tetracarboxylic dianhydride satisfying the structure of the general formula (4), and the following chemical formula (71) (3-phenyltricyclo [ 6,2,2,0 ^2,7 ] dodeca-2,11-ene-5,6,9,10-tetracarboxylic dianhydride) . Regarding the structure determination of the compound, Non-Patent Document 1 was also referred to.

1 g of the above tetracarboxylic dianhydride represented by the chemical formula (1) is dissolved in 10 ml of THF, 100 mg of 10% palladium / carbon catalyst (manufactured by Kojima Pharmaceutical) is added, and 50 ° C., 5 to 4.50 MPa ( Hydrogen reduction was carried out for 16 hours. After removing the catalyst, THF was distilled under reduced pressure to recover white crystals in a yield of 95%.
When the ¹ HNMR spectrum of the crystal was measured in the same manner as described above, the peak area attributed to two hydrogen atoms of the carbon / carbon double bond portion appearing in the region of δ = 6.00 to 6.25 disappeared. It was shown that the carbon / carbon double bond (disubstituted olefin) at the 11th position in the chemical formula (1) was hydroreduced. On the other hand, when δ = 1.00 to 2.00, no cycloalkane methine hydrogen appeared, indicating that no nuclear hydrogenation of the aromatic ring occurred. There were no other major changes. Further, it was confirmed from IR spectrum analysis that an anhydrous carbonyl group remained, and from the result of mass spectrum, it was confirmed that the molecular weight was 378, which was 2 more than the compound of the chemical formula (1).
From this result, it was confirmed that the hydrogenation product is a tetracarboxylic dianhydride represented by the following chemical formula (2) that satisfies the structure of the general formula (1).

1 g of tetracarboxylic dianhydride represented by the chemical formula (1) is dissolved in 10 ml of THF, 50 mg of 10% palladium / carbon catalyst (manufactured by Kojima Pharmaceutical) is added, and 100 ° C., 1 to 0.95 MPa (hydrogen pressure) ) For 6 hours. After removing the catalyst, THF was distilled under reduced pressure to recover white crystals in a yield of 95%.
When the ¹ HNMR spectrum of the crystal was measured in the same manner as described above, the peak area attributed to two hydrogen atoms of the carbon / carbon double bond portion appearing in the region of δ = 6.00 to 6.25 and δ = The ratio of the peak area attributed to the five hydrogen atoms of the monosubstituted benzene ring portion appearing in the region of 7.20 to 7.45 changed from 2: 5 before the reduction treatment to 1.2: 5 In addition, a new methine hydrogen peak appeared near δ = 6.00, and a part of the carbon / carbon double bond (2-substituted olefin) at the 11th position in the chemical formula (1) was hydrogenated and reduced. showed that.
On the other hand, at δ = 1.00 to 2.00, no cycloalkane-based methine hydrogen appeared, indicating that no aromatic ring nuclear hydrogenation occurred. There was no significant change other than this. Further, it was confirmed from IR spectrum analysis that an anhydrous carbonyl group remained.
From this result, the reduction treatment compound has a chemical formula satisfying about 60 mol% of tetracarboxylic dianhydride represented by the chemical formula (1) satisfying the structure of the general formula (4) and a structure of the general formula (1). It was confirmed that it was composed of about 40 mol% of tetracarboxylic dianhydride represented by (2).
Hereinafter, the mixture obtained by this method is referred to as “hydrogenated tetracarboxylic dianhydride mixture A”.

1 g of the tetracarboxylic dianhydride represented by the chemical formula (1) is dissolved in 10 ml of THF, 100 mg of 10% palladium / carbon catalyst (manufactured by Kojima Pharmaceutical) is added, 120 ° C., 9.00 to 8.50 MPa. Hydrogen reduction was carried out for 16 hours at (hydrogen pressure). After removing the catalyst, THF was distilled under reduced pressure to recover white crystals in a yield of 95%.
When the ¹ HNMR spectrum of the crystal was measured in the same manner as described above, a peak attributed to two hydrogen atoms of the carbon / carbon double bond portion appearing in the region of δ = 6.00 to 6.25 and δ = The peak attributed to the hydrogen atom of the aromatic ring appearing in the 7.20 to 7.00 region disappears, and the carbon-carbon double bond (2-substituted olefin) at the 11th position in the chemical formula (1) is hydroreduced. And showed that the aromatic ring was nuclear hydrogenated. On the other hand, cycloalkane methine hydrogen appeared at δ = 1.00 to 2.00. Further, it was confirmed from IR spectrum analysis that an anhydrous carbonyl group remained, and from the result of mass spectrum, it was confirmed that the molecular weight was 386, which is 8 more than the compound of the chemical formula (1).
From this result, it was confirmed that the said reduction process compound is the tetracarboxylic dianhydride represented by following Chemical formula (93) which satisfies the structure of General formula (2).
The synthesis route of these alicyclic tetracarboxylic dianhydride compounds is shown in FIG.

1 g of tetracarboxylic dianhydride represented by the chemical formula (1) is dissolved in 10 ml of THF, 50 mg of 10% palladium / carbon catalyst (manufactured by Kojima Pharmaceutical) is added, and 100 ° C., 1 to 0.95 MPa (hydrogen pressure) ) For 6 hours. After removing the catalyst, THF was distilled under reduced pressure to recover white crystals in a yield of 95%.
When ¹ HNMR spectrum measurement of the crystal was performed in the same manner as described above, the peak area attributed to two hydrogen atoms of the carbon / carbon double bond appearing in the region of δ = 6.00 to 6.25 disappeared, It was shown that the carbon-carbon double bond (2-substituted olefin) at the 11-position in the chemical formula (1) was hydrogenated and reduced. Further, the peak area attributed to five hydrogen atoms of the mono-substituted benzene ring portion appearing in the region of δ = 7.20 to 7.45 and δ = 1.00 to 2.00 include cycloalkane methine hydrogen. Newly appeared. There were no other major changes. Further, it was confirmed from IR spectrum analysis that an anhydrous carbonyl group remained.
From the ratio of the respective peak areas, the reduction treatment compound is about 50 mol% of tetracarboxylic dianhydride represented by the chemical formula (2) satisfying the structure of the general formula (1) and the structure of the general formula (2). It was confirmed that it was composed of about 50 mol% of tetracarboxylic dianhydride represented by the chemical formula (3) satisfying
Hereinafter, the mixture obtained by the method is referred to as “hydrogenated tetracarboxylic dianhydride mixture B”.

(Reference Example 1) <Synthesis of polyamic acid>
752 mg (2 mmol) of tetracarboxylic dianhydride represented by the chemical formula (1), 400 mg (2 mmol) of 4,4′-diaminodiphenyl ether and 1.5 ml of N, N-dimethylacetamide as a solvent are placed in a 30 ml eggplant flask. The reaction was stirred for one day at room temperature. The reaction solution became viscous.
Subsequently, 15 ml of N, N-dimethylacetamide was added to the reaction solution and dissolved to lower the consistency, and the reaction solution was poured into 150 ml of methanol. The precipitate was collected by filtration and washed with excess methanol. The logarithmic viscosity was 2.3.

<Structure determination of polyamic acid>
(IR spectrum measurement)
1540 cm −1, 1680 cm −1 Amide bond attribution peak 1780 cm −1, 1860 cm −1 Disappearance of carboxylic acid anhydride attribution peak IR spectrum is shown in FIG. 3.
From the above analysis results, it was confirmed that the polyamic acid according to Reference Example 1 has a repeating unit structure represented by the following chemical formula (4).

<Synthesis of polyimide>
752 mg (2 mmol) of tetracarboxylic dianhydride represented by the chemical formula (1), 400 mg (2 mmol) of 4,4′-diaminodiphenyl ether and 1.5 ml of N, N-dimethylacetamide as a solvent are placed in a 30 ml eggplant flask. The reaction was stirred for one day at room temperature. The reaction solution became viscous.
Subsequently, the reaction solution was heated at 100 ° C. for 30 minutes and at 200 ° C. for 2 hours under reduced pressure. After cooling to room temperature, 15 ml of N, N-dimethylacetamide was added and dissolved to lower the consistency, and the reaction solution was poured into 150 ml of methanol. The precipitate was collected by filtration and washed with excess methanol. The composite was a light gold powder and the yield was 100%.

<Polyimide structure determination>
(IR spectrum measurement)
Disappearance of 1540 cm −1, 1680 cm −1 amide bond attribution peak 1710 cm −1, 1780 cm −1 Imide bond attribution peak 1780 cm −1, 1860 cm −1 Disappearance of carboxylic acid anhydride attribution peak IR spectrum is shown in FIG. 4.
From the above analysis results, it was confirmed that the polyimide according to Reference Example 1 has a repeating unit structure represented by the following chemical formula (5).

(Examples 1-4)
Instead of 2 mmol of tetracarboxylic dianhydride represented by chemical formula (1) in Reference Example 1, a tetracarboxylic dianhydride represented by chemical formula (2) (hereinafter referred to as “Example 1”), chemical formula (3) tetracarboxylic dianhydride (hereinafter referred to as “Example 2”), hydrogenated tetracarboxylic dianhydride mixture A (hereinafter referred to as “Example 3”), hydrogenated tetra. A polyamic acid and polyimide were synthesized in the same manner as in the reference example except that the carboxylic acid dianhydride mixture B (hereinafter referred to as “Example 4”) was about 2 mmol, and the IR spectrum was synthesized. The structure was determined. The yield in each synthesis reaction was almost the same, and the assignment of IR spectrum was also almost the same.

  It was confirmed that the polyamic acid according to Example 1 (having a logarithmic viscosity of 2.1) has a repeating unit structure represented by the following chemical formula (6), and polyimide has the following chemical formula (7).

  It was confirmed that the polyamic acid according to Example 2 (having a logarithmic viscosity of 2.1) has a repeating unit structure represented by the following chemical formula (8) and polyimide has the following chemical formula (9).

  The polyamic acid according to Example 3 (having a logarithmic viscosity of 2.0) has a repeating unit structure of chemical formula (4) and chemical formula (6), and polyimide is a repeating chemical formula (5) and chemical formula (7). It was confirmed to have a unit structure.

  The polyamic acid according to Example 4 (having a logarithmic viscosity of 2.2) has a repeating unit structure of chemical formula (6) and chemical formula (8), and polyimide is a repeating unit of chemical formula (7) and chemical formula (9). It was confirmed to have a structure.

<Solubility in organic solvents such as polyimide>
When 5 mg of each polyamic acid and polyimide obtained in Examples 1 to 4 above were weighed and put into 5 ml of dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) and N-methylpyrrolidone at room temperature, all The organic solvent was dissolved immediately after the addition. The solution was substantially transparent.

(Reference Example 2)
In the above Reference Example 1, when the polyamic acid and polyimide synthesized by replacing the tetracarboxylic dianhydride of the chemical formula (1) with pyromellitic dianhydride were similarly evaluated, the polyamic acid was dimethyl sulfoxide (DMSO), Although the solution was dissolved in N, N-dimethylformamide (DMF) and N-methylpyrrolidone, the solution was colored, and the brown polyimide was not dissolved at all and remained precipitated.

<Light transmittance of polyimide>
The polyimides obtained in Reference Example 1 and Examples 1 to 4 were dissolved in N-methylpyrrolidone (0.1% by mass), placed in a 1 cm square quartz cell, a bandwidth of 2 nm, a scanning speed of 200 nm / min. The UV-absorption spectrum was measured. All polyimides had an absorption edge of 330 nm or less, and did not show absorption in the visible region (400 to 780 nm). The light transmittance in the visible range is 90% in the reference example, 92% in the examples 1 and 3, 94% in the examples 2 and 4, and the alicyclic tetracarboxylic dianhydride. It can be seen that even a polyimide composed of a physical compound is extremely excellent in light transmittance.

<Thermal analysis of polyimide, etc.>
TGA measurement was performed on the polyimide according to Reference Example 1 under a nitrogen atmosphere at a temperature increase rate of 20 ° C./min. The 5% weight loss temperature was 320 ° C., and it was confirmed to have heat resistance as a liquid crystal alignment film application. Moreover, the weight residual ratio in 600 degreeC was 37%, and the characteristic which is hard to produce coking by heat decomposition was confirmed.
The 5% weight loss temperature and the weight residual ratio at 600 ° C. of the polyimides according to Examples 1 to 4 are 355 ° C. (50%) in Example 1, 355 ° C. (44%) in Example 2, and 335 in Example 3. It can be seen that the temperature is 42 ° C. (42%) and 355 ° C. (44%) in Example 4 is extremely excellent in heat resistance even among polyimides composed of alicyclic tetracarboxylic dianhydride compounds. Moreover, the characteristic which is hard to produce caulking by thermal decomposability with respect to the aromatic polyimide was confirmed from comparison with Reference Example 2 described later.

  When the polyimide of Reference Example 2 was evaluated in the same manner, the weight residual ratio at 600 ° C. was 82%, respectively, and it was confirmed that the resin was thermally decomposable and easily caulked.

The polyimide according to the present invention can be used in parts of various industrial parts such as separation claws and bearings of copying machines as molding parts, and parts of office automation equipment such as copying machines, as well as existing polyimides as molding materials.
In addition, it is a polyimide film that is excellent in heat resistance and moldability and is soluble in organic solvents, as a base material for flexible printed wiring boards and heat-resistant adhesive tapes, and as a resin varnish for semiconductor insulation film, protective film, heat resistance Low dielectric adhesives such as low dielectric adhesives with excellent adhesive properties, film-like bonding materials, adhesive laminates, flexible printed circuit boards (FPC) and TAB (Tape Automated Bonding) tapes, composite lead frames, laminate materials, etc. It is suitable for production of a laminated structure for uses requiring heat resistance and adhesiveness, and can be used for an alignment film for liquid crystal display elements.

Reaction path diagram for producing tetracarboxylic dianhydride Reaction path diagram for producing tetracarboxylic dianhydride according to the example IR spectrum of polyamic acid IR spectrum of polyimide

Claims (3)

A polyamic acid obtained by reacting at least one of tetracarboxylic dianhydrides represented by the following general formulas (1) and (2) with a diamine represented by the following general formula (3).

In the general formulas (1) and (2), R1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms. m and n are arbitrary integers of 0 to 5 independent of each other. When m + n is plural, plural R2s may be the same or different from each other.

In the general formula (3), R3 represents a divalent organic group. At least one of the tetracarboxylic dianhydrides represented by the general formulas (1) and (2) according to claim 1 and the tetracarboxylic dianhydride represented by the following general formula (4) and the general formula ( A polyamic acid obtained by reacting the diamine represented by 3).

In General Formula (4), R1 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms. m and n are arbitrary integers of 0 to 5 independent of each other. When m + n is plural, plural R2s may be the same or different from each other.   A polyimide obtained by dehydrating and ring-closing the polyamic acid according to claim 1.

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