JP2009185204A - Polyimide oligomer and polyimide resin formed by heating/curing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To polyimide oligomer having excellent thermal moldability, excellent heat resistant as a polyimide after being heated/cured and inexpensively obtainable. <P>SOLUTION: The polyimide oligomer contains a diamine component containing at least one or more kinds of non-axisymmetric aromatic diamine expressed by general formula (1) and an acid dianhydride component as constituent monomers (in the formula, X is a direct bond, -O-, -NH-, -CH<SB>2</SB>-, -C<SB>2</SB>H<SB>4</SB>-, -C(CH<SB>3</SB>)-, -CF<SB>2</SB>-, -C<SB>2</SB>F<SB>4</SB>-, -C(CF<SB>3</SB>)<SB>2</SB>-, -C(=O)-, -S-, -S(=O)- or -S(=O)<SB>2</SB>-). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermosetting polyimide oligomer, particularly a polyimide oligomer that is excellent in moldability and can obtain a polyimide resin excellent in heat resistance by heat curing.

  Polyimide resin is excellent in heat resistance and exhibits a very high thermal decomposition temperature, and is therefore used as a carbon fiber reinforced structural material matrix in the fields of rockets and artificial satellites (for example, see Non-Patent Document 1). In recent years, in the field of LSIs using Si wafers, electronic parts using Si-C have been actively researched as information is densified and increased in speed, and LSIs using Si-C are 400 ° C. Although operation at a temperature exceeding is assumed, even if a conventional polyimide resin, which is said to be excellent in heat resistance, is used, it cannot be handled. Therefore, use of various heat-resistant polymer films as well as polyimide resins has been studied (for example, see Non-Patent Document 2).

  On the other hand, the polyimide resin has high heat resistance, so that there is a problem that the crystal structure is strong, the melting / melting characteristics are lacking, and the molding is difficult. In recent years, research and development of polyimide oligomers having thermosetting properties have been promoted for such problems. That is, by adding a crosslinking reactive functional group such as 4-phenyl ethynyl phthalic anhydride to the end of the polyimide oligomer, the polyimide oligomer is molded and then the crosslinking reaction between the polymer chains proceeds by heating. It is intended to obtain a polyimide resin molded body which is cured and has high heat resistance.

  Further, for the purpose of improving the dissolution / melting characteristics of such polyimide oligomers or the properties of the resulting polyimide resin, for example, non-axial such as 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride. A polyimide oligomer into which a symmetric biphenyl dianhydride is introduced has been proposed (see, for example, Patent Document 1). In addition, the normal polyimide structure has high linearity and very large intermolecular interaction, but by introducing such a non-axisymmetric molecule, the polyimide chain exhibits spirality, so intermolecular interaction It becomes clear that heat melting property and coloring property are improved (see, for example, Non-Patent Document 3).

JP 2000-219741 A Supervised by Masaaki Enomoto, “Latest Polyimide Materials and Applied Technologies”, CM Publishing “Research on practical application and introduction of SiC power electronics”, New Functional Device Research and Development Association, March 2005 Masatoshi Hasegawa et al., Macromolecules, 1999, 32, p382.

However, the non-axisymmetric acid dianhydride monomer used in Patent Document 1 is difficult to synthesize and is relatively expensive, and thus the high heat resistance and thermoformability obtained in this way. It was practically difficult to apply these polyimide oligomers to various fields.
That is, an object of the present invention is to provide a polyimide oligomer that has excellent thermoformability and excellent heat resistance as a polyimide resin after heat curing, and can be obtained easily and inexpensively.

  As a result of intensive studies in view of the problems of the prior art, the present inventors obtained a non-axisymmetric aromatic diamine in which two amino groups are not introduced on the same axis as a diamine component. In order to complete the present invention, it is found that the polyimide oligomer having a helical property is excellent in thermoformability, and that the polyimide resin obtained by heat curing the polyimide oligomer exhibits excellent heat resistance. It came.

（上記式において、Ｘは、直接結合、−Ｏ−、−ＣＨ_２−、−Ｃ_２Ｈ_４−、−Ｃ（ＣＨ_３）_２−、−ＣＦ_２−、−Ｃ_２Ｆ_４−、−Ｃ（ＣＦ_３）_２−、−Ｃ（＝Ｏ）−、−ＮＨ−、−Ｓ−、−Ｓ（＝Ｏ）−、又は−Ｓ（＝Ｏ）_２−である） That is, the polyimide oligomer according to the present invention contains a diamine component containing at least one non-axisymmetric aromatic diamine represented by the following general formula (1) and an acid dianhydride component as constituent monomers. It is characterized by.

(In the above formula, X represents a direct bond, —O—, —CH ₂ —, —C ₂ H ₄ —, —C (CH ₃ ) ₂ —, —CF ₂ —, —C ₂ F ₄ —, —C (CF ₃ ) ₂ —, —C (═O) —, —NH—, —S—, —S (═O) —, or —S (═O) ₂ —.

The polyimide oligomer preferably has a crosslinkable reactive group at both ends.
In the polyimide oligomer, it is preferable that the average degree of polymerization is 2 to 12 and the average molecular weight is 8000 or less.

In the polyimide oligomer, the non-axisymmetric diamine is selected from 3,4'-diaminophenyl ether, 3,4'-diaminophenylmethane, 3,4'-diaminobenzophenone, and 3,4'-benzidine. It is preferred that there are at least one or more.
In the polyimide oligomer, the diamine component preferably has a ratio of the non-axisymmetric aromatic diamine in the total amount of the diamine component of 90 mol% or more.

  In the polyimide oligomer, the diamine component other than the non-axisymmetric aromatic diamine is 4,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4- Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 2,2-bis [4- (4-Aminophenoxy) phenyl] hexafluoropropane, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, 3,3′-bis (4-aminophenyl) fluorene It is suitable that it is a seed or more.

  In the polyimide oligomer, the acid dianhydride component is pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-biphthalic acid dianhydride. 3,3 ′, 4,4′-diphenylsulfonic acid, 4,4 ′-(hexafluoroisopyridene) diphthalic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,4,9, 10-perylenetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride, 2,2-bis It is preferable that it is at least one selected from (4-carboxylic acid phenyl) propanoic acid dianhydride.

  In the polyimide oligomer, the crosslinkable reactive group is 4-phenylethynylphthalic anhydride, phthalic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, 2,5-norbornadiene-2,3. -It is preferably derived from at least one compound selected from dicarboxylic anhydride, maleic anhydride, propargylamine, phenylethynylaniline, ethynylaniline, aminostyrene, and vinylaniline.

The polyamic acid oligomer according to the present invention contains a diamine component containing at least one non-axisymmetric aromatic diamine represented by the general formula (1) and an acid dianhydride component as constituent monomers. It is characterized by this.
In addition, the polyimide resin according to the present invention is obtained by heat-curing the polyimide oligomer.

  According to the present invention, by using a non-axisymmetric aromatic diamine in which two amino groups are not introduced on the same axis as a diamine component, the obtained polyimide oligomer has a helical property. A polyimide oligomer having excellent moldability and excellent heat resistance as a polyimide resin after heat curing can be obtained.

The polyimide oligomer according to the present invention contains a diamine component containing at least one non-axisymmetric aromatic diamine represented by the following general formula (1) and an acid dianhydride component as constituent monomers. It is what.

  Here, the compound represented by the general formula (1) is one in which an amino group is bonded to each of the 3-position and 4-position on two benzene rings bonded directly or via a specific functional group, The bonding position of the amino group is not an axially symmetric position around X, that is, it is a non-axisymmetric aromatic diamine.

In the general formula (1), X represents a direct bond, —O—, —CH ₂ —, —C ₂ H ₄ —, —C (CH ₃ ) ₂ —, —CF ₂ —, —C ₂ F ₄ —. _{, -C (CF 3) 2 -} , - C (= O) -, - NH -, - S -, - S (= O) -, or -S (= _{O) 2} - a.

More specifically, the non-axisymmetric aromatic diamine represented by the general formula (1) is 3,4'-benzidine (X is directly bonded), 3,4'-diaminophenyl ether (X is- O -), 3,4'-diaminodiphenyl methane (X is _-CH 2 -), 3,4'- diaminodiphenyl phenylethane (X is _-C 2 _H 4 -), 3,4'- diaminophenyl isopropane ( X is —C (CH ₃ ) ₂ —), 3,4′-diaminophenyldifluoromethane (X is —CF ₂ —), 3,4′-diaminophenyltetrafluoroethane (X is —C ₂ F ₄ —) 3,4′-diaminophenylhexafluoroisopropane (X is —C (CF ₃ ) ₂ —), 3,4′-diaminobenzophenone (X is —C (═O) —), 3,4′-diamino Phenylamine (X is —NH—), 3,4′-diamino Phenyl sulfide (X is -S -), 3,4'-diaminodiphenyl phenyl sulfoxide (X is -S (= O) -), 3,4'- diaminophenyl sulfone (X is -S (= _{O) 2} −). Of these, 3,4′-diaminophenyl ether, 3,4′-diaminophenylmethane 3,4′-diaminobenzophenone, and 3,4′-benzidine can be preferably used. Phenyl ether or 3,4'-diaminophenylmethane can be preferably used. In addition, you may use these non-axisymmetric aromatic diamines individually by 1 type or in combination of 2 or more types.

  As a diamine component used for the polyimide oligomer of this invention, you may use combining diamine components other than the said non-axisymmetric aromatic diamine. The non-axisymmetric aromatic diamine is only required to contain at least one molecule as a diamine component, and the ratio of the non-axisymmetric aromatic diamine in the total amount of the diamine component is not particularly limited, Preferably, it is 80 mol% or more, more preferably 90 mol% or more in the total amount of the diamine component. More preferably, the total amount of the diamine component may consist only of the non-axisymmetric aromatic diamine.

  When a diamine component other than the non-axisymmetric aromatic diamine (that is, an axially symmetric diamine component) is used in the present invention, it may be anything as long as it can form a polyimide structure by condensation reaction with an acid dianhydride. It is not limited. Examples of such a diamine component include 4,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis ( 4-aminophenoxy) benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane , Α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, 3,3′-bis (4-aminophenyl) fluorene, and the like. In addition, you may use these axially symmetric aromatic diamines in combination of 2 or more types. Of these, 4,4′-diaminodiphenyl ether and 1,3-bis (3-aminophenoxy) benzene can be preferably used. The ratio of these axially symmetric diamine components is not particularly limited, but is preferably less than 20 mol%, more preferably less than 10 mol% in the total amount of diamine components.

  The acid dianhydride component used for the polyimide oligomer of the present invention is not particularly limited as long as it can form a polyimide structure by condensation reaction with diamine. Examples of the acid dianhydride used in the present invention include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-biphthalic acid dianhydride, 3 , 3 ′, 4,4′-diphenylsulfonic acid, 4,4 ′-(hexafluoroisopyridene) diphthalic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,4,9,10- Perylenetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic dianhydride, 2,2-bis (4 -Carboxylic acid phenyl) propanoic acid dianhydride and the like. In addition, as the acid dianhydride component, a known non-axisymmetric acid dianhydride component may be used, and as such a non-axisymmetric acid dianhydride component, for example, 3, 4 ′ -Biphthalic dianhydride, 3,4 '-(hexafluoroisopyridene) diphthalic dianhydride, 3,4'-oxydiphthalic dianhydride, etc. are mentioned. In addition, you may use these acid dianhydride components in combination of 2 or more types. Of these acid dianhydride components, 4,4′-oxydiphthalic acid dianhydride and 4,4′-biphthalic acid dianhydride can be preferably used.

  The polyimide oligomer of the present invention preferably has a crosslinkable reactive group at both ends. Thermosetting is imparted by modifying the terminal with a compound having a crosslinkable reactive group. Examples of the compound having a crosslinkable reactive group used in the present invention include 4-phenylethynylphthalic anhydride, phthalic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, and 2,5-norbornadiene-2. , 3-dicarboxylic acid anhydride, maleic acid anhydride, propargylamine, phenylethynylaniline, ethynylaniline, aminostyrene, vinylaniline and the like. Of these, 4-phenylethynylphthalic acid anhydride and 5-norbornene-2,3-dicarboxylic acid anhydride can be preferably used.

  In the polyimide oligomer of this invention, it forms by the alternating bond of a diamine component and an acid dianhydride component, and the average degree of polymerization which makes this polyimide repeating unit one unit is 2-20. In addition, this average degree of polymerization can be suitably adjusted by changing the quantity and reaction time of the diamine component and acid dianhydride component used for manufacture of a polyimide oligomer. If the average degree of polymerization exceeds 20 in the polyimide oligomer of the present invention, the heat meltability may be inferior and molding may be difficult. From the viewpoint of the moldability of the polyimide oligomer, the average degree of polymerization is preferably 2 to 12, and more preferably 4 to 10. When the average degree of polymerization is within the above range, a polyimide oligomer particularly excellent in moldability can be obtained.

  In the polyimide oligomer concerning this invention, the oligomer chain | strand has shown the helical structure as a whole by having the non-axisymmetric aromatic diamine represented by the said General formula (1) in an oligomer chain | strand. For this reason, since the polyimide oligomer according to the present invention is thermally melted at a relatively low temperature, thermoforming is easy, and the thermal decomposition temperature of the polyimide resin after heat curing reaches 500 ° C. or higher, and also in heat resistance. Very good.

  Note that, for example, the conventional helical polyimide oligomer described in Patent Document 1 is excellent in thermoformability and heat resistance of the polyimide resin after heat curing, but is a relatively expensive non-axisymmetric compound. Therefore, there has been a problem that a great deal of cost is required in production. On the other hand, the helical polyimide oligomer according to the present invention can greatly reduce the manufacturing cost by using a non-axisymmetric aromatic diamine which is available at a relatively low cost, and has excellent thermoformability and heat curing. A polyimide oligomer having heat resistance of the subsequent polyimide resin can be obtained easily and inexpensively.

In addition, the polyimide oligomer concerning this invention can be prepared by the following process, for example.
(A) A diamine component containing at least one non-axisymmetric aromatic diamine represented by the general formula (1) is reacted with an acid dianhydride component to prepare a polyamic acid.
Here, the polymerization degree can be appropriately adjusted by changing the addition ratio and reaction time of the diamine component and the acid dianhydride component. In this invention, it is necessary to adjust the addition ratio of each said component so that the average degree of polymerization of a polyimide repeating unit may be 2-20.

  Examples of the solvent used in the reaction include aprotic solvents such as N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide, NN-dimethylacetamide (DMAc), and γ-butyrolactam. It is done. When the polymerization reaction is carried out in an aprotic solvent, it is usually obtained as a polyamic acid oligomer having an amide moiety and a carboxylic acid moiety in the molecule. This polyamic acid oligomer is, for example, added to an imidizing agent at a low temperature, or heated and refluxed at a high temperature to dehydrate and cyclize (imidize) the amide moiety and the carboxylic acid moiety to form a polyimide oligomer. be able to.

(B) Furthermore, the compound which has a crosslinkable reactive group is added to the terminal of the polyimide oligomer or polyamic acid oligomer obtained above.
Since this crosslinkable reactive group forms a cross-linked structure by heating, the thermosetting property can be imparted to the polyimide oligomer.
Here, the crosslinkable reactive group-containing compound may be any compound that can react with either the unreacted carboxylic acid group in the acid dianhydride or the unreacted amino group in the diamine. What is necessary is just to adjust the addition amount of a crosslinkable reactive group containing compound suitably according to the equivalent of the reactive carboxylic acid group or amino acid group.

  The reaction in the above step (B) can be carried out continuously with the step (A). Usually, all steps (A) and (B) are carried out in the state of polyamic acid oligomer, and finally converted into a polyimide oligomer. . That is, in the state of the polyamic acid oligomer obtained in the step (A), the crosslinkable reactive group-containing compound is added in the step (B), followed by, for example, adding an imidizing agent at a low temperature, or at a high temperature. By heating to reflux, the amide moiety and the carboxylic acid moiety are dehydrated and cyclized (imidized) to obtain a polyimide oligomer having a crosslinkable reactive group at the molecular end.

  In addition, the polyamic acid oligomer which has not been imidized in the steps (A) and (B) is also within the scope of the present invention. Such a polyamic acid oligomer can be easily converted into a polyimide oligomer by dehydration and cyclization reaction by heating. For example, the polyimide oligomer of the present invention can be obtained by heating and refluxing the polyamic acid oligomer solution of the present invention at a high temperature of about 150 to 245 ° C. Alternatively, for example, the polyimide oligomer of the present invention can be obtained by applying a polyamic acid oligomer solution onto a support having good releasability such as a glass plate and heating to about 250 to 350 ° C. .

  In the reaction steps (A) and (B), both are preferably performed in the presence of an inert gas such as argon or nitrogen, or in a vacuum.

  In addition, by reacting a non-axisymmetric aromatic diamine in advance with a large excess of acid dianhydride, acid dianhydride is formed on both side chains centered on one molecule of non-axisymmetric aromatic diamine. It is possible to prepare an oligomer precursor condensed with a compound. Then, by adding another diamine component to the oligomer precursor (including unreacted acid dianhydride) thus obtained and further performing a polycondensation reaction, a non-axisymmetric aromatic diamine is obtained. It is also possible to obtain a polyimide oligomer in which is disposed only at the center of the oligomer chain.

  The polyimide oligomer obtained as described above can be used as it is after the reaction. For example, after the reaction is completed, the solution after the reaction is stirred into a large amount of water and isolated by filtration. By drying at about 100 ° C., it can be used as a powdered polyimide oligomer. Also. The polyimide oligomer powder thus obtained can also be used as a solution dissolved in an appropriate solvent, if necessary.

  In addition, the polyimide oligomer obtained as described above can be made into a polyimide resin having excellent heat resistance by heating and curing the oligomer alone or impregnating a fibrous reinforcing material such as carbon fiber. it can. In addition, since the polyimide oligomer according to the present invention exhibits a spiral structure and is excellent in moldability, for example, it can be easily molded by a mold or the like, or can be applied to a fibrous reinforcing material or the like. Impregnation can also be performed relatively easily.

  Further, when the polyimide oligomer is heat-cured, the heating temperature and the heating time can be appropriately adjusted according to the desired physical properties of the polyimide resin. In addition, although the polyimide oligomer concerning this invention changes also with the kind etc. of a crosslinkable reactive group containing compound, it thermosets normally at about 300-370 degreeC. More specifically, for example, the polyimide oligomer is thermally melted by preliminary heating at a temperature of about 210 to 320 ° C. for a certain period of time, and then the crosslinking reaction is performed by heating at a temperature of 350 to 400 ° C. for a certain period of time. A polyimide resin cured product is obtained. Usually, the heat resistance of the cured polyimide resin is improved by increasing the heating temperature in each heating step or increasing the heating time.

  In addition, what is necessary is just to perform manufacture of the polyimide resin molding using the polyimide oligomer of this invention according to a well-known method. For example, the polyimide oligomer powder of the present invention is filled in a mold, and heat compression molding is performed at 250 to 370 ° C. and about 0.5 to 5 MPa for about 1 to 5 hours to obtain a polyimide resin molded body. . Further, for example, after impregnating a fibrous reinforcing material such as carbon fiber with the polyimide oligomer solution of the present invention and heating and drying at 180 to 260 ° C. for about 1 to 5 hours, further under pressure, at 1 to 5 at 250 to 370 ° C. By heating for about an hour, a fiber-containing composite of polyimide resin can be obtained. Moreover, for example, the polyimide oligomer solution of the present invention is applied onto a support having good peelability such as a glass plate and heated at 250 to 350 ° C. for about 1 to 5 hours to obtain a polyimide resin film. it can.

Hereinafter, the present invention will be described in more detail based on the description of Examples, but the present invention is not limited to these Examples.

Under a stream of argon, 23.15 g of 3,4′-diaminodiphenyl ether and 26.80 g of 4,4′-oxydiphthalic anhydride were dissolved in 200 ml of N, N-dimethylacetamide and stirred at room temperature for about 30 minutes. Thereafter, 14.29 g of 4-phenylethynylphthalic anhydride was added, and the mixture was stirred at room temperature for about 1 hour, and then the solvent was refluxed for about 12 hours to obtain an off-white suspension. The suspension was poured into 800 ml of ion-exchanged water, and after filtration, washing with water was repeated several times, washing with methanol, filtration, and drying overnight at 120 ° C. to obtain an off-white powdery polyimide oligomer. The obtained polyimide oligomer was measured by GPC (Aliance 2695: manufactured by Waters), and as a result, the number average molecular weight (Mn) was 5.2 × 10 ³ g / mol (NMP solvent).

  Next, after taking the required amount of polyimide oligomer powder on the polyimide film as described above, after melting and defoaming at 230 ° C. for 1 hour on a hot press, pressurizing at 350 ° C. and 2 Mpa for 1 hour to obtain a cured polyimide resin Obtained.

The polyimide resin cured product obtained above was analyzed by TG-DTA (EASTAR6000: manufactured by SII) under a nitrogen stream. As a result, the 5% thermal decomposition temperature (τ ₅ ) was 563.3 ° C. (in a nitrogen stream, rising) The temperature rate was 10 degrees / minute). Further, TMA: the measurement by (EASTAR6000 manufactured by SII), the glass transition temperature of the cured polyimide resin _{(T g)} is 316.4 ° C. (under nitrogen stream, heating rate: 10 ° C. / min) was.
Moreover, the thermal expansion coefficient (CTE) of the polyimide resin cured product measured by TMA (EASTAR6000: manufactured by SII) was 31 ppm. Moreover, it was 3.2 GPa as a result of measuring an initial stage elasticity modulus (EZGraph: made by Shimadzu) as a polyimide resin hardened | cured material as a film about 75 micrometers thick.

Under an argon stream, 18.97 g of 3,4′-diaminodiphenyl ether and 22.82 g of 3,3 ′, 4,4′-benzophenone terephthalic dianhydride were dissolved in 200 ml of N, N-dimethylacetamide, and the room temperature was about 30 minutes. Stirring under. Thereafter, 11.72 g of 4-phenylethynylphthalic anhydride was added and stirred at room temperature for about 1 hour, and then the solvent was refluxed for about 12 hours to obtain a greenish white suspension. The suspension was poured into 800 ml of ion-exchanged water, filtered and washed with water several times, washed with methanol and filtered, and dried overnight at 120 ° C. to obtain a greenish white powdery polyimide oligomer. In addition, about the obtained polyimide oligomer, as a result of measuring by GPC (Aliance2695: made by Waters), the number average molecular weight (Mn) was 5.2x10 < ³ > g / mol (NMP).

  Next, after taking the required amount of polyimide oligomer powder to the polyimide film as described above, after melting and defoaming at 250 ° C. for 0.5 hours on hot press, further pressurizing at 350 ° C. and 2 Mpa for 1.5 hours to discolor A transparent polyimide resin cured product was obtained.

The polyimide resin cured product obtained above was analyzed by TG-DTA (EASTAR6000: manufactured by SII) under a nitrogen stream. As a result, the 5% thermal decomposition temperature (τ ₅ ) was 563.3 ° C. (in a nitrogen stream, rising) The temperature rate was 10 degrees / minute). Further, TMA: the measurement by (EASTAR6000 manufactured by SII), the glass transition temperature of the cured polyimide resin _{(T g)} is 316.4 ° C. (under nitrogen stream, heating rate: 10 ° C. / min) was.
Moreover, the thermal expansion coefficient (CTE) of the polyimide resin cured product measured by TMA (EASTAR6000: manufactured by SII) was 31 ppm. Moreover, it was 3.2 GPa as a result of measuring an initial stage elasticity modulus (EZGraph: made by Shimadzu) as a polyimide resin hardened | cured material as a film about 75 micrometers thick.

In a stream of argon, 4.73 g of 3,4′-diaminodiphenylmethane was dissolved in 100 ml of N, N-dimethylacetamide, and 6.84 g of 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride was added to obtain about 60 Stir for a minute at room temperature. Thereafter, 2.37 g of 4-phenylethynylphthalic anhydride was added and stirred at room temperature for about 1 hour, and then the solvent was refluxed for about 12 hours. The reaction solution was poured into 500 ml of ion-exchanged water, filtered and washed with water several times, washed with methanol and filtered, and then dried overnight at 120 degrees to obtain a milky white powdery polyimide oligomer. In addition, about the obtained polyimide oligomer, as a result of measuring by GPC (Aliance2695: made by Waters), the number average molecular weight (Mn) was 4.5x10 < ³ > g / mol (NMP solvent).

  Subsequently, the polyimide oligomer powder was taken in a sample bottle as described above, and heated under a nitrogen stream at 250 ° C. for 2 hours, 280 ° C. for 5 hours, 320 ° C. for 2 hours, and 350 ° C. for 2.5 hours. An amber transparent polyimide resin cured product was obtained.

The polyimide resin cured product obtained above was analyzed by TG-DTA (EASTAR 6000: manufactured by SII) under a nitrogen stream. As a result, the 5% thermal decomposition temperature (τ ₅ ) was 557.3 ° C. (ascended under a nitrogen stream). The temperature rate was 10 degrees / minute). Further, TMA: the measurement by (EASTAR6000 manufactured by SII), the glass transition temperature of the cured polyimide resin _{(T g)} is 330.0 ° C. (under nitrogen stream, heating rate: 10 ° C. / min) was.
Moreover, the thermal expansion coefficient (CTE) of the polyimide resin hardened | cured material measured by TMA (EASTAR6000: SII company make) was 38 ppm. Moreover, it was 2.8 GPa as a result of measuring an initial stage elasticity modulus (EZGraph: made by Shimadzu) as a polyimide resin hardened | cured material as a film about 75 micrometers thick.

3.92 g of 3,4'-diaminodiphenylmethane was dissolved in 200 ml of N, N-dimethylacetamide under an argon stream, 36.29 g of 3,4'-oxydiphthalic anhydride was added, and the mixture was stirred for about 30 minutes at room temperature. Thereafter, 40.78 g of 9,9-bis (4-aminophenyl) fluorene was added and stirred for about 1 hour to obtain a viscous solution. Further, 9.68 g of 4-phenylethynylphthalic anhydride was added, and the mixture was stirred at room temperature for about 1 hour, and then the solvent was refluxed for about 12 hours. The reaction solution was poured into 800 ml of ion-exchanged water, filtered and washed with water several times, washed with methanol and filtered, and dried overnight at 120 ° C. to obtain a white powdery polyimide oligomer. The obtained polyimide oligomer was measured by GPC (Aliance 2695: manufactured by Waters), and as a result, the number average molecular weight (Mn) was 5.2 × 10 ³ g / mol (NMP solvent).

  Subsequently, as described above, a required amount of polyimide oligomer powder is taken into a sample bottle, heated at 250 ° C. for 0.5 hours under a nitrogen stream, and further pressurized at 350 ° C. for 1.5 hours under 2 Mpa pressure condition. C. for 2 hours, 280.degree. C. for 5 hours, 320.degree. C. for 1.5 hours, and 350.degree.

The polyimide resin cured product obtained above was analyzed by TG-DTA (EASTAR6000: manufactured by SII) under a nitrogen stream. As a result, the 5% thermal decomposition temperature (τ ₅ ) was 563.3 ° C. (in a nitrogen stream, rising) The temperature rate was 10 degrees / minute). Further, TMA: the measurement by (EASTAR6000 manufactured by SII), the glass transition temperature of the cured polyimide resin _{(T g)} is 316.4 ° C. (under nitrogen stream, heating rate: 10 ° C. / min) was.
Moreover, the thermal expansion coefficient (CTE) of the polyimide resin cured product measured by TMA (EASTAR6000: manufactured by SII) was 31 ppm. Moreover, it was 3.2 GPa as a result of measuring an initial stage elasticity modulus (EZGraph: made by Shimadzu) as a polyimide resin hardened | cured material as a film about 75 micrometers thick.

  As shown in each of the above examples, by using a non-axisymmetric aromatic diamine in which two amino groups are not introduced on the same axis as a diamine component, the obtained polyimide oligomer has excellent thermoformability. Moreover, it was confirmed that the polyimide resin obtained by heat-curing this polyimide oligomer exhibits excellent heat resistance and mechanical properties.

Claims (10)

A polyimide oligomer comprising a diamine component containing at least one non-axisymmetric aromatic diamine represented by the following general formula (1) and an acid dianhydride component as constituent monomers.

(In the above formula, X represents a direct bond, —O—, —CH ₂ —, —C ₂ H ₄ —, —C (CH ₃ ) ₂ —, —CF ₂ —, —C ₂ F ₄ —, —C (CF ₃ ) ₂ —, —C (═O) —, —NH—, —S—, —S (═O) —, or —S (═O) ₂ —.   The polyimide oligomer according to claim 1, which has a crosslinkable reactive group at both ends.   The polyimide oligomer according to claim 1 or 2, wherein the average degree of polymerization is 2 to 20, and the average molecular weight is 8000 or less.   The polyimide oligomer according to any one of claims 1 to 3, wherein the non-axisymmetric diamine is 3,4'-diaminophenyl ether, 3,4'-diaminophenylmethane, 3,4'-diaminobenzophenone, 3 Polyimide oligomer characterized by being at least one selected from 4,4'-benzidine.   The polyimide oligomer according to any one of claims 1 to 4, wherein the ratio of the non-axisymmetric aromatic diamine in the total amount of the diamine component is 90 mol% or more.   The polyimide oligomer according to any one of claims 1 to 5, wherein the diamine component other than the non-axisymmetric aromatic diamine is 4,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, 3,3′-bis (4-amino) A polyimide oligomer characterized by being at least one selected from phenyl) fluorene.   The polyimide oligomer according to any one of claims 1 to 6, wherein the acid dianhydride component is pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 4'-biphthalic acid dianhydride, 3,3 ', 4,4'-diphenylsulfonic acid, 4,4'-(hexafluoroisopyridene) diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride , 3,4,9,10-perylenetetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,4 ′-(hexafluoroisopropylidene) diphthalic acid A polyimide oligomer comprising at least one selected from an anhydride and 2,2-bis (4-carboxylic acid phenyl) propanoic dianhydride.   The polyimide oligomer according to any one of claims 1 to 7, wherein the crosslinkable reactive group is 4-phenylethynylphthalic anhydride, phthalic anhydride, 5-norbornene-2,3-dicarboxylic acid anhydride, , 5-norbornadiene-2,3-dicarboxylic acid anhydride, maleic anhydride, propargylamine, phenylethynylaniline, ethynylaniline, aminostyrene, vinylaniline A polyimide oligomer.   A polyamic acid oligomer comprising a diamine component containing at least one non-axisymmetric aromatic diamine represented by the general formula (1) and an acid dianhydride component as constituent monomers.   A polyimide resin obtained by heat-curing the polyimide oligomer according to claim 1.