JP2013241553A - Thermosetting polyimide comprising cardo type diamine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide oligomer that can be readily thermoformed, yields a polyimide resin excellent in heat resistance after being heated and cured at a low temperature and exhibits large elongation at break.SOLUTION: A polyimide oligomer has a nonaxisymmetric aromatic acid anhydride and an aromatic diamine, has a crosslinkable terminus comprising an ethynylphthalic anhydride residue (4-EPA), a 4-methylethynylphthalic anhydride residue (4-META) or a 4-phenylethynylphthalic anhydride residue (4-PEPA) and is represented by formula (1), which represents a schematic diagram of a chemical structure of the polyimide oligomer, and formula (2) (wherein X is a direct bond, O or CO).

Description

The present invention is a thermosetting polyimide oligomer, particularly excellent in thermoformability at low temperatures, is soluble in highly polar solvents such as N-methylpyrrolidone, γ-butyrotactone, aquamid ^TM , and is heat resistant by heat curing. It is related with the polyimide oligomer which can obtain the polyimide resin excellent in the property.

  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 (see, for example, 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 solubility / meltability is 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 crosslinkable functional group such as 4-phenylethynylphthalic anhydride to the end of the polyimide oligomer, the polyimide oligomer is molded, and then the crosslink reaction between the oligomer chains is advanced by heating to cure the resin. And it is going to obtain the polyimide resin molding which has high heat resistance.

  Furthermore, 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).

  In addition, as the diamine, for example, a polyimide oligomer using a bent diamine such as 4,4′-diaminodiphenyl ether and a linear diamine such as 3,4′-diaminodiphenyl ether in a specific ratio, It has been reported that it is suitable for molding a polyimide resin by resin transfer molding (RTM) or resin injection (RI) technology (for example, see Patent Document 2).

  However, polyimides obtained from polyimide oligomers as described in Patent Documents 1 and 2 exhibit a dark brown color after thermosetting, and it is practically difficult to apply the obtained polyimide oligomers to various optical fields. Met.

  On the other hand, in the linear thermosetting polyimide using 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, not only the solubility of the oligomer in the organic solvent is improved, but also the prepared film is Heat-curing diamine that is confirmed to show yellow to pale yellow and is bulky and has no conjugation in the molecule such as 1,3,3, -trimethyl1-1H-indene-5 (or 6) -amine (TMDA) If it employ | adopts as a main composition of an electroconductive polypolyimide oligomer, it thought that the thermosetting polyimide which does not show a color more may be obtained (for example, refer nonpatent literature 4).

  In addition, the crosslinkable reactive group used at the terminal of the polyimide oligomer has been studied, and conventionally, 4-phenylethynylphthalic acid, in particular, is said to have an excellent balance of moldability, heat resistance, mechanical properties, etc. Widely used (see, for example, Patent Document 3). However, the crosslinkable reactive group used in these conventional polyimide oligomers requires a high temperature for the crosslinking reaction (thermosetting), and cannot be said to be sufficient for application to resin molded products in various fields.

  JP 2000-219741 A   US Pat. No. 6,359,107   JP 2007-99969 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.   Hongwei Zhou, C.I. C. , Reito Kanbara, Takeshi Sasaki, Rikio Yokota, High Performance Polymers, 2005, 17, p213.

  The present invention has been made in view of the above-mentioned problems of the prior art. The problem to be solved is that thermoforming is easy, and the polyimide resin after heat curing has excellent heat resistance and is easily N The object is to provide a polyimide oligomer that can be dissolved in a highly polar solvent such as methylpyrrolidone. Furthermore, it is ideally desired to be colorless and transparent as a sealing material for optical elements such as EL and LCD.

  As a result of intensive studies conducted by the present inventors in view of the problems of the prior art, the non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a- BPDA) is 3 or more molecules per tetramer, 1,3,3, -trimethyl1-1H-indene-5 (or 6) -amine (TMDA) is 3 molecules or more per tetramer and the main composition is 3, 4′-diaminodiphenyl ether (3,4′-ODA), 1,4-bis (4-aminophenoxy) benzene (1,4,4-APB), 1,3-bis (3-aminophenoxy) benzene (1 , 3,3-APB), 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB) and having at least one molecule and no more than one molecule, and the crosslinkable terminal is ethynyl. Phthalic anhydride residue (4-E A), consisting of 4-methylethynylphthalic anhydride residue (4-META) or 4-phenylethynylphthalic anhydride residue (4-PEPA), and represented by the following general formula (1) Characterized polyimide oligomer. In addition, by using 4-methylethynylphthalic anhydride as a crosslinkable reactive group at the end, a polyimide oligomer having excellent dissolution / melting characteristics and excellent thermoformability capable of primary curing at low temperature can be obtained. Furthermore, the present inventors have found that a polyimide resin obtained by heat-curing this polyimide oligomer exhibits excellent heat resistance, and completed the present invention.

That is, the polyimide oligomer according to the present invention has a non-axisymmetric site derived from non-axisymmetric 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride as an acid dianhydride main molecule in the oligomer chain. 3 or more molecules per monomer, 1,3,3, -trimethyl 1-1H-indene-5 (or 6) -amine (TMDA) as a diamine main molecule, 3 or more molecules per tetramer, 3,4 ′ -Diaminodiphenyl ether (3,4'-ODA), 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene (1,3,3-APB), 1,3 -Bis (4-aminophenoxy) benzene (1,3,4-APB) only 1 molecule or less, and the crosslinkable terminal is an ethynylphthalic anhydride residue (4-EPA), 4-methylethynylphthalic acid It consists of an anhydride residue (4-META) or 4-phenylethynylphthalic anhydride residue (4-PEPA), and is represented by the following general formula (1).

  In the polyimide oligomer, the average degree of polymerization n and n ′ of each imide repeating structure is the average degree of polymerization of each imide repeating structure, n is 1 to 12, n ′ is 0 to 6, n + n ′ ≦ 12, and The average molecular weight of the entire polyimide oligomer is preferably 8000 or less.

  Further, in the polyimide oligomer, the acid dianhydride residue is required to have 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride at least 3 molecules per tetramer, and depending on the physical properties, acid dianhydride And at least one acid diacid selected from 4,4′-oxydiphthalic acid dianhydride, 4,4′-biphthalic acid dianhydride, and 3,3 ′, 4,4′-diphenylsulfonic acid. Anhydrides can be introduced.

  Further, in the polyimide oligomer, the diamine residue is 1,3,3, -trimethyl1-1H-indene-5 (or 6) -amine (TMDA) is essential for 3 or more molecules per tetramer, and 3 depending on the purpose. , 4′-diaminodiphenyl ether (3,4′-ODA), 1,4-bis (4-aminophenoxy) benzene (1,4,4-APB), 1,3-bis (3-aminophenoxy) benzene ( It is preferably derived from at least one diamine selected from 1,3,3-APB) and 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB). Some of these diamino residues are 4,4′-diaminodiphenyl ether, 1,2-bis (4-aminophenoxy) benzene (1,2,4-APB), 4,4′-diaminodiphenyl ether (4, 4′-ODA), 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, 1,1-bis [4- (4-aminophenoxy) phenyl] Cyclohexane can also be used.

（ｎ、ｎ’は各イミド繰り返し構造の平均重合度でｎは１〜１６、ｎ’は０〜８である。）In addition, the amic acid oligomer according to the present invention comprises 3 or more molecules of non-axisymmetric acid dianhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride per tetramer and 3 or more molecules of TMDA. As main molecules, 3,4-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene (1,4,4-APB), 1,3-bis (3-aminophenoxy) benzene (1,3,3) 3-APB), 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB) selected from diamines alone or in combination and characterized by an oligomer chain having only one molecule or less, and a crosslinkable terminal Consists of 4-methylethynylphthalic anhydride residue and is represented by the following general formula (2).

(N and n ′ are average polymerization degrees of each imide repeating structure, n is 1 to 16, and n ′ is 0 to 8.)

  In addition, the polyimide resin according to the present invention, after chemically imidizing the amic acid oligomer, after distilling off the chemical imidizing agent, or imidization by heat condensation, the polyimide oligomer varnish, etc. is charged into methanol, etc. It is formed by precipitation, pulverization, and heat curing.

  According to the present invention, a non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride in which two carboxylic acid anhydride groups are not introduced on the same axis is represented by 4 At least 3 molecules per monomer are arranged in a polyimide oligomer chain, and 3 or more molecules of 1,4-bis (4-aminophenoxy) benzene are essential as an aromatic diamine, and 3,4′-diaminodiphenyl ether, 1,3- One molecule of diamine selected from bis (3-aminophenoxy) benzene (1,3,3-APB) and 1,3-bis (4-aminophenoxy) benzene (1,3,4-APB) alone or in combination By introducing 4-methylethynylphthalic anhydride as a cross-linkable reactive group at the terminal having only the following, it has excellent dissolution / melting characteristics and can be used at low temperature. It can be obtained excellent polyimide oligomers readily to curable thermoformability. Moreover, the polyimide resin obtained by heat-curing this polyimide oligomer powder exhibits excellent heat resistance.

  The polyimide oligomer according to the present invention comprises 3 or more molecules of non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride per tetramer, 1,4-bis (4 -Aminophenoxy) benzene 3 or more molecules, 3,4'-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene (1,3,3-APB), 1,3-bis (4-aminophenoxy) Benzene (1,3,4-APB) is selected according to the purpose and is introduced alone or in combination with 1 molecule or less having only 1 molecule or less per tetramer, and the crosslinkable terminal is 4-methylethynylphthalic anhydride It consists of chemical residues.

  The aromatic acid anhydride represented by the general formula (2) is a non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic acid dianhydride, 3 molecules per tetramer. More specifically, the acid dianhydride residue is 4,4′-oxydiphthalic acid dianhydride, 4,4′-biphthalic acid dianhydride, 3,3 ′, 4, depending on the physical properties. At least one or more acid dianhydrides selected from 4′-diphenylsulfonic acid can be introduced in an amount of 1 molecule or less per tetramer. In addition, 4,4'-oxydiphthalic dianhydride can be particularly preferably used.

  The aromatic diamine represented by the general formula (2) more specifically requires 3 or more molecules of TMDA per tetramer, and depending on the purpose, the diamine residue may be 3,4'-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene and 1,3-bis (4-aminophenoxy) benzene are preferably used, and 1,2-bis (4-aminophenoxy) benzene, 4,4′-diamino Diphenyl ether, 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 should also be used Can do. These aromatic diamines may be used alone or in combination of two or more in one molecule or less per tetramer.

  That is, the polyimide oligomer according to the present invention is a tetramer of the non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride represented by the general formula (1). 3 or more per molecule, 3 or more TMDA molecules, and 3,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, and 1,3-bis (4-aminophenoxy) benzene at each end A compound in which an amino group is added to a terminal of a polyimide oligomer chain formed by polycondensation of an arbitrary acid dianhydride and a diamine to an amino group, and thereby a non-axisymmetric aromatic anhydride 2,3 More than 3 molecules of 3 ′, 4′-biphenyltetracarboxylic dianhydride per tetramer and aromatic diamine more specifically 1,4-bis (4-aminophenyl). Noxy) an oligomer chain consisting of 3 or more molecules of benzene and 1,4'-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, or 1,3-bis (4-aminophenoxy) benzene is there.

Moreover, in the polyimide oligomer concerning this invention, a phthalic acid derivative is used as a compound for forming a crosslinkable terminal.
The acid anhydride used as a crosslinkable terminal compound in the present invention is a compound in which an acetylene group, a methylacetylene group, or a phenylacetylene group is substituted on a phthalic acid anhydride, and is a compound represented by the following general formula (3). is there.

  That is, the phthalic acid derivative anhydride represented by the above general formula (3) has an acid anhydride group condensed with an arbitrary amino group at the end of the polyimide oligomer chain to form an imide bond, and a crosslinkable reactive group. Added as.

  A normal polyimide oligomer is imparted with thermosetting properties by modifying the terminal with a crosslinkable terminal compound. As the crosslinkable terminal compound, for example, 4-phenylethynylphthalic anhydride is widely used. However, these conventional crosslinkable terminal compounds require a high temperature for the crosslinking reaction (thermosetting). Since the cured polyimide resin is very strong, it lacks flexibility in molding and is difficult to handle. In contrast, the polyimide oligomer of the present invention can be primarily cured at a lower temperature than before by using 4-methylethynylphthalic anhydride as a crosslinkable terminal compound. For this reason, for example, it is possible to flexibly adopt a molding method suitable for the target product, such as taking an approximate mold by primary curing at low temperature, then finely molding and then secondary curing at high temperature.

The polyimide oligomer according to the present invention is represented by the following general formula (1).

  In the above general formulas (1) and (2), X is an acid dianhydride residue. The acid dianhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride used for the polyimide oligomer of the present invention is non-axisymmetric and has 3 or more molecules per tetramer, and other 4 amounts. The acid dianhydride copolymerized by 1 molecule or less per body is not particularly limited as long as it can form a polyimide structure by condensation reaction with diamine. Examples of the copolymer dianhydride used in the present invention include 4,4′-oxydiphthalic dianhydride (ODPA), 4,4′-biphthalic dianhydride (s-BPDA), 3,3 ′, 4,4′-diphenylsulfonic acid dianhydride and the like. Of these, 4,4′-oxydiphthalic dianhydride can be particularly preferably used.

  In the general formulas (1) and (2), the diamine used in the polyimide oligomer of the present invention is not particularly limited as long as it can form a polyimide structure by condensation reaction with an acid dianhydride. . As a diamine used in the present invention, 3 or more molecules of TMDA are essential per tetramer, and 3,4′-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene or 1,3-bis (3 -Aminophenoxy) benzene is used in one molecule or less. In addition, 1,2-bis (4-aminophenoxy) benzene, 4,4′-diaminodiphenyl ether, 1,3-bis (3-aminophenoxy) benzene, 1,3-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 can be used. Of these, 3,4'-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, and 1,3-bis (3-aminophenoxy) benzene can be preferably used.

  In the above general formulas (1) and (2), in the polyimide oligomer of the present invention, the terminal is modified with 4-methylethynylphthalic anhydride, so that a conventional crosslinkable terminal compound (for example, 4-phenylethynylphthalate) is obtained. It becomes possible to perform primary curing at a lower temperature than the acid anhydride). For this reason, the polyimide oligomer of the present invention can flexibly select and adopt an appropriate molding method according to the target product when manufacturing a polyimide resin molded product, and can be applied to a wider range of molded products. Become.

  In the above general formulas (1) and (2), n and n ′ are the average degree of polymerization of the imide repeating structure, and the average degree of polymerization (n + n ′) is 1 to 12. In addition, this average degree of polymerization can be suitably adjusted by changing the ratio of the aromatic diamine and acid dianhydride used for manufacture of a polyimide oligomer. In the polyimide oligomer of the present invention, if the average degree of polymerization n + n ′ of each imide repeating structure exceeds 12, the meltability may be inferior and molding may be difficult. From the viewpoint of the moldability of the polyimide oligomer, the average degree of polymerization (n + n ′) of each imide repeating structure is preferably 1 to 12, and more preferably 2 to 8. When the average degree of polymerization of each imide repeating structure is within the above range and n is larger than n ′, a polyimide oligomer having particularly high breaking elongation can be obtained.

  In the polyimide oligomer according to the present invention, as shown in the general formulas (1) and (2), the non-axisymmetric acid dianhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride is used. 3 or more molecules per tetramer, 3 or more molecules of diamine main composition TMDA, 3,4'-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene and 1,3-bis (3-aminophenoxy) benzene Is the basic structure of an oligomer chain consisting of 1 molecule or less, and the oligomer chain as a whole shows a helical structure. As a result, since the polyimide oligomer according to the present invention is melted at a relatively low temperature, thermoforming is easy, and the thermal decomposition temperature of the heat-cured polyimide resin reaches 500 ° C. or more, resulting in heat resistance. Is also very good.

  In addition, for example, although the conventional helical polyimide oligomer as described in Patent Document 1 is excellent in thermoformability and heat resistance of the polyimide resin after heat curing, the solubility in the reaction solvent is There is a problem that it is low and costs a great deal in manufacturing. In contrast, the polyimide oligomer according to the present invention is a polyimide oligomer that dissolves in an organic solvent such as N-methyl-2-pyrrolidone (NMP) and has excellent thermoformability and heat resistance of the polyimide resin after heat curing. It can be obtained easily and inexpensively.

  The amidic acid oligomer obtained as described above was added with a chemical imidizing agent while stirring the solution after completion of the reaction. By leaving it under vacuum at about 60 ° C. for several hours, it can be used as a polyimide oligomer solution. Moreover, it is heat-dehydrated and used as a polyimide oligomer varnish. Furthermore, the polyimide oligomer powder obtained by stirring in alcohol and making it drop-precipitate can be filtered and dried for use.

  In addition, the polyimide oligomer obtained as described above can be made into a polyimide matrix resin having excellent heat resistance by heating and curing the oligomer alone or impregnating a fibrous reinforcing material such as carbon fiber. Can do. In addition, since the polyimide oligomer according to the present invention exhibits meltability 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 easily.

  In addition, when the polyimide oligomer is heat-cured, the heating temperature and the heating time can be adjusted by appropriately selecting a crosslinking group in accordance with the physical properties of the desired polyimide resin. In addition, the polyimide oligomer concerning this invention starts primary hardening at about 280-300 degreeC, for example, when MEPA is selected with a crosslinking group. More specifically, for example, the polyimide oligomer is thermally melted by preliminary heating at a temperature of about 200 ° C. for a predetermined time, and then primary curing is performed by heating at a temperature of about 300 ° C. for a predetermined time. A cured polyimide resin having excellent heat resistance and mechanical properties can be obtained by heating at a temperature of 340 ° C. for a certain period of time and secondary curing. In addition, the heat resistance of a polyimide resin hardened | cured material usually improves by raising the heating temperature in each heating process, or lengthening a 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, when MEPA is selected as a cross-linking group, the polyimide oligomer powder of the present invention is filled in a mold, and heat compression molding is performed at 300 ° C. and about 0.5 to 5 MPa for about 1 to 12 hours to perform primary molding. Goods can be obtained. Subsequently, a polyimide resin molded article having excellent heat resistance and mechanical properties can be obtained by heat compression molding at 350 ° C. and about 0.5 to 5 MPa for about 1 to 3 hours. If it is not necessary to obtain a primary molded product, the heat treatment compression treatment may be performed directly at a high temperature of about 300 to 350 ° C. Further, for example, after impregnating the fibrous oligomer varnish of the present invention into a fibrous reinforcing material such as carbon fiber and heating and drying at 120 to 200 ° C. for about 1 to 3 hours, further under pressure, 230 to 350 ° C. at 1 to 5 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 to a copper foil, the solvent is distilled off at 120 to 200 ° C., and the mixture is heated at 250 to 350 ° C. for about 1 to 5 hours to produce a copper-clad laminate. Further, it was found that a polyimide resin film can be obtained by coating on a support having good peelability such as a glass plate and heating at 250 to 350 ° C. for about 1 to 5 hours.

７−８としたポリイミドオリゴマーを例示すると（他も７−８と同じ操作手順）、四つ口フラスコ（３００ｍｌ）を室温下、窒素置換し、窒素気流下、Ｎ／Ｎ〜３０％となるように、ＴＭＤＡ１８．５４ｇ、３，４’−ジアミノジフェニルエーテル６．３５ｇとａ−ＢＰＤＡ２４．８８ｇを加え、攪拌しながら、ＮＭＰ１１０ｇを室温下攪拌する。二時間後温度センサーが発熱の終了を確認後、４−メチルエチニルフタル酸無水化物を３．９５ｇとＮＭＰ７ｇを加え、二時間後温度センサーで発熱の終了を確認した。その後、窒素気流下溶剤存在下、加熱還流を２４時間続け、淡い黄色を呈したポリイミドオリゴマーワニスを得た。
その後、洗浄乾燥させたガラス板にカプトンテープを用い、成形型とし、ガラス棒を用い、均一にガラス板に塗布し、１９０℃で１時間乾燥させ、３４０℃で２時間加熱処理をした。冷却後、ナイフで切れ目を入れ、水の入ったビーカーにガラス板ごと付けた。剥離したフィルムを室温で一昼夜乾燥させ、幅３ｍｍ、長さ５０ｍｍに切り取り、膜厚測定後、力学試験を行った。 Example 1

When the polyimide oligomer made into 7-8 is illustrated (the other operation procedure is the same as 7-8), the four-necked flask (300 ml) is purged with nitrogen at room temperature, and N / N to 30% in a nitrogen stream. To this, TMDA 18.54 g, 3,4'-diaminodiphenyl ether 6.35 g and a-BPDA 24.88 g are added, and NMP 110 g is stirred at room temperature while stirring. Two hours later, after the temperature sensor confirmed the end of heat generation, 3.95 g of 4-methylethynylphthalic anhydride and 7 g of NMP were added, and the temperature sensor confirmed the end of heat generation after two hours. Thereafter, heating under reflux was continued for 24 hours in the presence of a solvent in a nitrogen stream to obtain a polyimide oligomer varnish exhibiting a pale yellow color.
Thereafter, a Kapton tape was used for the glass plate that had been washed and dried to form a mold, and a glass rod was used to uniformly apply to the glass plate, dried at 190 ° C. for 1 hour, and heat-treated at 340 ° C. for 2 hours. After cooling, a cut was made with a knife, and the glass plate was attached to a beaker containing water. The peeled film was dried at room temperature for a whole day and night, cut into a width of 3 mm and a length of 50 mm, measured for film thickness, and then subjected to a mechanical test.

The following is the polyimide oligomer

  The physical production of various polyimide oligomers obtained in accordance with the polyimide oligomer obtained as described above was examined with a tetramer. The results are shown in Table 2.

  Furthermore, the relationship between the composition of 7 and the number of masses was examined. However, although the composition ratio is slightly different from the stability of the NMP solution, the results obtained are shown in Table 3.

About the polyimide resin hardened | cured material obtained above, the tensile test was measured in the constant temperature and humidity chamber using Shimadzu Corp. make and ASGS-1kNG. For T _g, measured by the TA manufactured by Q200TA. TG-DTA was estimated using a DTG-50 manufactured by Shimadzu Corporation under a nitrogen atmosphere at a rate of sound increase of 100 ° C./mm ⁻¹ . The linear expansion coefficient CTE is measured under the TMA-50 temperature rising rate 100 ° C./mm ⁻¹ , load 10.0 g, air atmosphere, manufactured by Shimadzu Corporation. For example, in 7-8, CTE = 19.8 ppm can be used as an electronic material. I understood that.

Example 2
The oligomer solution polymerized in Example 1 was diluted with 100 ml of NMP, the reaction solution was poured into 400 ml of water, filtered, washed with water several times, dried at 80 ° C. overnight, and a yellow powdered polyimide oligomer was obtained. It was.

The polyimide oligomer powder obtained above is taken in a polyimide film, melted and degassed on a hot press at 250 ° C for 0.5 hours, and then defoamed and added for 10 minutes at 250 ° C and 2 MPa on a hot press. The pressure was repeated and heated at 320 ° C. for 2 hours (heating rate 5 ° C./min) to obtain a cured polyimide resin. Under a nitrogen stream, a result of analysis by TG-DTA, 5% thermal decomposition temperature of 568.5 ° C. (heating rate 10 ° C. / min), _{T g} is 262.0 ° C. by DSC (heating rate 10 ° C. / min) CTE was confirmed to be 21 ppm. The initial elastic modulus of the film having a thickness of about 50 μm was 3.0 GPa, the breaking strength was 208.7 MPa, and the breaking elongation was 32.0%.

Comparative Examples Imide numbers 1, 3, 4, and 5 shown in Table 1 are comparative examples.

From the results of Examples 1 and 2 above, 3 or more molecules of 1,4-bis (non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride per tetramer are obtained. (4-aminophenoxy) benzene has 3 or more molecules per tetramer, 3,4-diaminodiphenyl ether has only 1 molecule or less, and the crosslinkable terminal consists of 4-ethynylphthalic anhydride residue. Polyimide oligomer represented by the formula (1) In the polyimide oligomers of Examples 1 and 2, the film can be easily obtained, so that it is possible to perform primary molding at a lower temperature than before. It was. Moreover, 5% thermal decomposition temperature ((tau) ₅ ) of the polyimide resin hardened | cured material obtained by thermosetting this polyimide oligomer was 500 degreeC or more, and it was confirmed that it is excellent also in heat resistance. Moreover, it turned out that the mechanical property of the obtained polyimide resin hardened | cured material is also a favorable thing.

  In addition, it can be estimated that the oligomer chain of Example 1 has a helical structure as a whole. As a result of the fact that the oligomer chain exhibits spirality as described above, it is considered that thermoforming can be easily performed at a lower temperature as compared with conventional polyimide oligomers having high linearity (crystallinity). In addition, by using 4-ethynylphthalic anhydride as a crosslinkable terminal compound, primary curing can be performed at a lower temperature than before, and thus it is considered that application to a wider range of molded products becomes possible. Furthermore, by using 1,4-bis (4-aminophenoxy) benzene as the main molecule, the heat-cured polyimide resin has excellent heat resistance and mechanical characteristics represented by a large elongation at break. , 3,4′-diaminodiphenyl ether and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride ensure solubility, achieve low temperature curing and solubility in organic solvents, Bis (4-aminophenoxy) benzene achieves a high elongation at break.

Schematic diagram of chemical structure of polyimide oligomer of the present invention Schematic diagram of the chemical structure of the polyimide oligomer of Example 1 Schematic diagram of chemical structure of terminal crosslinking group of polyimide oligomer of the present invention

Claims (8)

3 or more molecules of non-axisymmetric aromatic acid anhydride 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue per tetramer, 4,4′-oxydiphthalic acid dianhydride residue or 1,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue, 3,3,3 ′, 4′-benzophenonetetracarboxylic dianhydride residue Aminophenyl) 1,3,3, -trimethyl1-1H-indene-5 (or 6) -amine residue is 4 or more and 5 molecules or less, 3,4-diaminodiphenyl ether residue, 1,3-bis ( 3-aminophenoxy) benzene residue, 1,3-bis (4-aminophenoxy) benzene residue, alone or in combination, having only one molecule or less, and having a crosslinkable terminal 4-ethynylphthalic anhydride residue, 4-methylethynylphthal A polyimide oligomer comprising a sulfonic anhydride residue or a 4-phenylethynylphthalic acid residue and represented by the following general formula (1).

(In the above formula (1), n is the average degree of polymerization of the imide repeating structure, n is 1 to 12, and n is 0 to 3)   The polyimide oligomer according to claim 1, wherein the average molecular weight of the whole polyimide oligomer is 8000 or less. The polyimide oligomer according to any one of claims 1 to 3, wherein the amic acid oligomer is characterized by the following general formula (2).

  The polyimide that can be imidized by a heat dehydration reaction in the presence of a polar solvent such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, γ-butyrolactone, aquamid (TM), etc. Oligomer.   The polyamic acid oligomer according to claim 3, wherein a chemical imidizing agent such as triethylamine / acetic anhydride is used at a low temperature of 60 ° C or lower, and after imidation, the remaining chemical imidizing agent and its by-products are distilled off under reduced pressure. The resulting polyimide oligomer and its varnish. A polyimide oligomer and a varnish thereof obtained by the amidic acid oligomer according to claim 3, wherein the terminal cross-linking group R is a polyamic acid oligomer having CH ₃ , C ₆ H ₅ , and is obtained after heat immobilization with heating under reflux.   The powder polyimide oligomer obtained by precipitating the polyimide oligomer obtained by Claim 1, 2, 4, 5, 6 using alcohol, such as methanol.   The polyimide resin according to claim 1, wherein the oligomer according to claim 1 is cured by heating and has a film thickness of 20 μm and an absorbance at 350 mm of 0.2 or less.

Images