JP7103940B2 - Method for producing imide oligomer composition, curing agent, adhesive, and imide oligomer composition - Google Patents

Description

The present invention relates to an imide oligomer that can be used in a cured product having excellent long-term heat resistance. The present invention also relates to a curing agent made of the imide oligomer and an adhesive made of the curing agent. Furthermore, the present invention relates to a method for producing the imide oligomer.

Curable resins such as epoxy resins, which have low shrinkage and are excellent in adhesiveness, insulation, and chemical resistance, are used in many industrial products. In particular, in electronic device applications, curable resin compositions that give good results in a solder reflow test for short-time heat resistance and a cold-heat cycle test for repeated heat resistance are often used.

In recent years, in-vehicle electric control units (ECUs), power devices using SiC and GaN, and the like have been attracting attention, but curable resin compositions used in these applications have heat resistance for a short time or repeatedly. However, heat resistance (long-term heat resistance) when continuously exposed to high temperature for a long period of time is required.

As a curing agent used in a curable resin composition, Patent Document 1 discloses an imide oligomer curing agent having an acid anhydride structure at both ends, but the compatibility with a curable resin such as an epoxy resin is high. Since it is insufficient, there is a problem that the obtained curable resin composition is inferior in long-term heat resistance.

On the other hand, Patent Documents 2 and 3 disclose a curable resin composition using a polyimide having a flexible silicone skeleton or an alicyclic skeleton as a curing agent in order to improve compatibility with a curable resin. There is. However, when a silicone skeleton or an alicyclic skeleton is introduced, the glass transition temperature of the obtained cured product tends to decrease, and the mechanical strength and long-term heat resistance at the operating temperature of the ECU, power device, etc. are inferior. was there. Further, Patent Document 4 discloses that the adhesiveness, heat resistance, etc. of a thermosetting resin composition are improved by using a specific imide oligomer having a phenolic hydroxyl group or the like at both ends as a curing agent. However, even when such an imide oligomer is used, the long-term heat resistance may decrease.

Japanese Unexamined Patent Publication No. 61-270852 Japanese Unexamined Patent Publication No. 2016-20437 Japanese Unexamined Patent Publication No. 2012-227534 International Publication No. 2005/100433

An object of the present invention is to provide an imide oligomer that can be used for a cured product having excellent long-term heat resistance. Another object of the present invention is to provide a curing agent composed of the imide oligomer and an adhesive made of the curing agent. Furthermore, an object of the present invention is to provide a method for producing the imide oligomer.

The present invention is an imide oligomer having a phenolic hydroxyl group, wherein the content ratio of the imide oligomer having an ester bond is 7% or less.
The present invention will be described in detail below.

The present inventors have found that among imide oligomers having a phenolic hydroxyl group, those having an ester bond have little effect of improving the long-term heat resistance of the cured product when used as a curing agent, and have a phenolic hydroxyl group. It was examined to use an imide oligomer having no ester bond. However, even when an imide oligomer having a phenolic hydroxyl group and no ester bond was used, the long-term heat resistance of the cured product could not be sufficiently improved. The reason why the present inventors could not sufficiently improve the long-term heat resistance of the cured product was that the ester bond was used as an impurity in the imide oligomer having a phenolic hydroxyl group used as having no ester bond. It was considered that this was because the imide oligomer having a small amount was present. Therefore, as a result of diligent studies, the present inventors have obtained a cured product having excellent long-term heat resistance by using an imide oligomer having a phenolic hydroxyl group in which the content ratio of the imide oligomer having an ester bond, which is an impurity, is 7% or less. We have found that we can do this, and have completed the present invention.

The imide oligomer of the present invention has a phenolic hydroxyl group.
The imide oligomer of the present invention contains 7% or less of the imide oligomer having an ester bond. When the content ratio of the imide oligomer having an ester bond is 7% or less, the imide oligomer of the present invention is excellent in the effect of improving the long-term heat resistance of the cured product obtained when used as a curing agent. .. The content ratio of the imide oligomer having the ester bond is preferably 5% or less, and most preferably 0%, that is, the imide oligomer having the ester bond is not contained.
The content ratio of the imide oligomer having an ester bond is derived from the ester bond by Fourier transform infrared spectroscopy (FT-IR) after each peak is separated by gel permeation chromatography (GPC). It can be obtained from the weight ratio of the compound having absorption. Specifically, first, a recycled preparative HPLC (manufactured by Nippon Analytical Industry Co., Ltd.) using tetrahydrofuran (THF) as a free liquid and equipped with a GPC column (for example, manufactured by Nippon Analytical Industry Co., Ltd., "JAIGEL-2H", etc.) was performed. Use to separate each peak. Then, the compound obtained by removing the free liquid by heating or the like is measured by a total internal reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer (for example, "UMA600" manufactured by Agilent Technologies). I do. From the obtained measurement results, it can be derived by determining the weight ratio of the weight of the compound having a peak (1159 cm ^-1 ) derived from the ester bond to the total peak compound.

From the viewpoint of long-term heat resistance of the obtained cured product, the imide oligomer of the present invention preferably has a phenolic hydroxyl group at the end of the main chain, and more preferably at both ends.

The preferred lower limit of the number average molecular weight of the imide oligomer of the present invention is 400, and the preferred upper limit is 4200. When the number average molecular weight is in this range, the cured product obtained when the imide oligomer of the present invention is used as a curing agent has excellent long-term heat resistance. The more preferable lower limit of the number average molecular weight of the imide oligomer of the present invention is 420, and the more preferable upper limit is 4000.
In the present specification, the above-mentioned "number average molecular weight" is a value obtained by measuring by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and converting it into polystyrene. Examples of the column used when measuring the number average molecular weight in terms of polystyrene by GPC include JAIGEL-2HA (manufactured by Nippon Analytical Industry Co., Ltd.).

Specifically, the imide oligomer of the present invention preferably contains an imide oligomer represented by the following formula (1-1) and / or an imide oligomer represented by the following formula (1-2) as a main component. ..
In addition, in this specification, the said "main component" means that the content ratio is 60 mol% or more.

In formulas (1-1) and (1-2), R ¹ and R ² are independently hydrogen atoms, halogen atoms, or monovalent hydrocarbon groups that may be substituted, and X is used. Is a bond, an oxygen atom, or a optionally substituted divalent hydrocarbon group, and in formula (1-2), Y may be a bond, an oxygen atom, or a substituted hydrocarbon group. It is a divalent hydrocarbon group.

As a method for producing the imide oligomer of the present invention, a method in which the amount of monoamine having a phenolic hydroxyl group used as a raw material is excessive is preferably used.
It has a step of reacting a compound having an acid anhydride group with a monoamine having a phenolic hydroxyl group, and the amount of the monoamine having a phenolic hydroxyl group used is relative to the acid anhydride group of the compound having an acid anhydride group. A method for producing an imide oligomer having an amount of 1.5 equivalents or more is also one of the present inventions. According to the method for producing an imide oligomer of the present invention, the imide oligomer of the present invention in which the content ratio of the imide oligomer having an ester bond generated as a by-product is 7% or less can be easily produced.

Specific examples of the method for producing the imide oligomer of the present invention are shown below.
First, a monoamine having a phenolic hydroxyl group in advance is dissolved in a solvent (for example, N, N-dimethylformamide, etc.) in which the amic acid oligomer obtained by the reaction is soluble, and acid dianhydride is added to the obtained solution. To obtain an amic acid oligomer solution. Next, the obtained amic acid oligomer solution is added to hydrochloric acid or the like, and the operation of recovering the precipitate is performed several times. By heating the obtained precipitate to proceed with the imidization reaction, an imide oligomer having a phenolic hydroxyl group can be obtained. When this method is used, the content ratio of the imide oligomer having an ester bond is set by setting the amount of the monoamine having a phenolic hydroxyl group to 1.5 equivalents or more with respect to the acid anhydride group having the acid anhydride. Can be 7% or less.

Further, another specific example of the method for producing an imide oligomer of the present invention is shown below.
First, the diamine is previously dissolved in a solvent (for example, N, N-dimethylformamide, etc.) in which the amic acid oligomer obtained by the reaction is soluble, and acid dianhydride is added to the obtained solution to cause a reaction. A solution of an amic acid oligomer (A) having an acid anhydride group at both ends is obtained. A monoamine having a phenolic hydroxyl group is added to the obtained solution of the amic acid oligomer (A) and reacted to obtain a solution of the amic acid oligomer (B). Next, the obtained solution of the amic acid oligomer (B) is added to hydrochloric acid or the like, and the operation of recovering the precipitate is performed several times. By heating the obtained precipitate to proceed with the imidization reaction, an imide oligomer having a phenolic hydroxyl group can be obtained. When this method is used, the amount of the monoamine having a phenolic hydroxyl group used is 1.5 equivalents or more with respect to the acid anhydride group of the amic acid oligomer (A) so that the imide oligomer having an ester bond can be used. The content ratio can be 7% or less.

As the monoamine having a phenolic hydroxyl group, a compound represented by the following formula (2) is preferably used.
Specific examples of the monoamine having a phenolic hydroxyl group include 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o-cresol, 4-amino-2,3-. Xylenol, 4-amino-2,5-xylenol, 4-amino-2,6-xylenol, 4-amino-1-naphthol, 5-amino-2-naphthol, 6-amino-1-naphthol, 4-amino- Examples thereof include 2,6-diphenylphenol. Among them, 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o- can be obtained because a cured product having excellent availability and storage stability and a high glass transition temperature can be obtained. Cresol is preferred.

In formula (2), Ar is a optionally substituted divalent aromatic group, and R ³ and R ⁴ are independently hydrogen atoms or optionally substituted monovalent hydrocarbon groups, respectively. Is.

As the acid dianhydride, a compound represented by the following formula (3) is preferably used.
Specific examples of the acid dianhydride include pyromellitic acid dianhydride, 3,3'-oxydiphthalic acid dianhydride, 3,4'-oxydiphthalic acid dianhydride, and 4,4'-oxydiphthalic acid. Dianoxide, 4,4'-(4,4'-isopropyridene diphenoxy) diphthalic acid anhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl ether, p-phenylene bis (trimeritate anhydride) ), 2,3,3', 4'-biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-carbonyldiphthalic acid dianhydride And so on. Among them, 4,4'-(4,4'-isopropyridenediphenoxy) diphthalic anhydride, 3,4'-oxydiphthalic anhydride, because of their excellent solubility, heat resistance, and availability. 4,4'-oxydiphthalic acid dianhydride and 4,4'-carbonyldiphthalic acid dianhydride are preferable.

In formula (3), A is a tetravalent group represented by the following formula (4-1) or the following formula (4-2).

In formulas (4-1) and (4-2), * is a bond position, and in formula (4-1), Z is a bond, an oxygen atom, a carbonyl group, or even if substituted. It is often a divalent hydrocarbon group that may have an oxygen atom at the bond position. The hydrogen atom of the aromatic ring in the formulas (4-1) and (4-2) may be substituted.

As the diamine, a compound represented by the following formula (5) is preferably used.
Specific examples of the diamine include, for example, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 3,4'-. Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 3,3'-diaminodiphenylsulphon, 4,4'-diaminodiphenylsulphon, Bis (4- (3-aminophenoxy) phenyl) sulphon, bis (4- (4-aminophenoxy) phenyl) sulphon, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-amino) Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, bis (4- (4-aminophenoxy) phenyl) methane, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 1 , 3-bis (2- (4-aminophenyl) -2-propyl) benzene, 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene, 3,3'-diamino-4, 4'-Dihydroxydiphenylmethane, 4,4'-diamino-3,3'-dihydroxydiphenylmethane, 3,3'-diamino-4,4'-dihydroxydiphenyl ether, 2,2-bis (3-amino-4-hydroxyphenyl) ) Propane, 2,2-bis (3-hydroxy-4-aminophenyl) propane, bisaminophenylfluorene, bistoluidinefluorene, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-diamino- 3,3'-dihydroxydiphenyl ether, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4'-diamino-2,2'-dihydroxybiphenyl, 4,4'-diamino-3,3'- Examples thereof include dihydroxybiphenyl, 4,4'-bis (4-aminobenzamide) -3,3'-dihydroxybiphenyl, 4,4'-bis (3-aminobenzamide) -3,3'-dihydroxybiphenyl and the like. .. Among them, because of their excellent solubility, heat resistance, and availability, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,2-phenylenediamine, 1,3-phenylenediamine, 1, 4-Phenylenediamine, bis (4- (3-aminophenoxy) phenyl) sulphon, bis (4- (4-aminophenoxy) phenyl) sulphon, 1,3-bis (2- (4-aminophenyl) -2- Propyl) benzene and 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene are preferred.

In the formula (5), B is a divalent group represented by the following formula (6-1) or the following formula (6-2), and R ⁵ to R ⁸ are independently hydrogen atoms or 1 respectively. It is a valent hydrocarbon group.

In formulas (6-1) and (6-2), * is a bond position, and in formula (6-1), Y is a bond, an oxygen atom, or a divalent optionally substituted. It is a hydrocarbon group of. The phenylene group in the formulas (6-1) and (6-2) may have some or all hydrogen atoms substituted with hydroxyl groups.

The preferable lower limit of the imidization ratio of the imide oligomer of the present invention is 70%. When the imidization ratio is 70% or more, a cured product having superior mechanical strength at high temperature and long-term heat resistance can be obtained when used as a curing agent. The more preferable lower limit of the imidization ratio is 75%, and the more preferable lower limit is 80%. Further, although there is no particular preferable upper limit of the imidization ratio of the imide oligomer of the present invention, the substantial upper limit is 98%.
The "imidization rate" can be determined by Fourier transform infrared spectroscopy (FT-IR). Specifically, the measurement is carried out by the total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer (for example, "UMA600" manufactured by Agent Technologies), and it is derived from the carbonyl group of the amic acid. It can be derived from the peak absorbance area near 1660 cm ^-1 by the following formula. The "peak absorbance area of the amic acid oligomer" in the following formula is determined by reacting a compound having an acid anhydride group with a monoamine having a phenolic hydroxyl group, and then evaporating the solvent without performing an imidization step. It is the absorbance area of the amic acid oligomer obtained by removing it.
Imidization rate (%) = 100 × (1- (peak absorbance area after imidization) / (peak absorbance area of amic acid oligomer))

As described above, the imide oligomer of the present invention can be used as a curing agent to obtain a cured product having excellent long-term heat resistance. The curing agent composed of the imide oligomer of the present invention is also one of the present inventions. An adhesive containing a curable resin and the curing agent of the present invention is also one of the present inventions.

Regarding the content of the curing agent of the present invention in the adhesive of the present invention, the preferable lower limit is 50 parts by weight and the preferable upper limit is 500 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the curing agent of the present invention is in this range, the cured product of the obtained adhesive becomes more excellent in long-term heat resistance. The more preferable lower limit of the content of the curing agent of the present invention is 70 parts by weight, and the more preferable upper limit is 400 parts by weight.

The adhesive of the present invention may contain other curing agents in addition to the curing agent of the present invention as long as the object of the present invention is not impaired in order to improve processability in an uncured state. ..
Examples of the other curing agents include phenol-based curing agents, thiol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, cyanate-based curing agents, active ester-based curing agents, and the like. Of these, phenol-based curing agents, acid anhydride-based curing agents, cyanate-based curing agents, and active ester-based curing agents are preferable.

When the adhesive of the present invention contains the other curing agent, the preferable upper limit of the content ratio of the other curing agent in the entire curing agent is 70% by weight, the more preferable upper limit is 50% by weight, and the further preferable upper limit is 30. By weight%.

The adhesive of the present invention contains a curable resin.
The curable resin is preferably liquid at 25 ° C. from the viewpoint of the fluidity and processability of the obtained adhesive.

As the curable resin, an epoxy resin is preferably used.
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, 2,2'-diallyl bisphenol A type epoxy resin, and hydrogenated bisphenol type epoxy resin. , Propoxy oxide-added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, naphthylene ether Type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, biphenyl novolac type epoxy resin, naphthalenephenol novolac type epoxy resin, glycidylamine type epoxy resin, alkyl polyol type epoxy resin, Examples include rubber-modified epoxy resins and glycidyl ester compounds. Of these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and resorcinol type epoxy resin are preferable because the viscosity is low and the processability of the obtained adhesive at room temperature can be easily adjusted.

The adhesive of the present invention may contain a curing accelerator. By containing the above-mentioned curing accelerator, the curing time can be shortened and the productivity can be improved.

Examples of the curing accelerator include an imidazole-based curing accelerator, a tertiary amine-based curing accelerator, a phosphine-based curing accelerator, a photobase generator, a sulfonium salt-based curing accelerator, and the like. Of these, an imidazole-based curing accelerator is preferable.

The content of the curing accelerator is preferably 0.01 part by weight and a preferable upper limit is 10 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the curing accelerator is in this range, the effect of shortening the curing time while maintaining excellent adhesiveness and the like becomes more excellent. The more preferable lower limit of the content of the curing accelerator is 0.05 parts by weight, and the more preferable upper limit is 5 parts by weight.

The adhesive of the present invention may contain an organic filler for the purpose of stress relaxation, toughness imparting, flame retardancy imparting and the like.
Examples of the organic filler include silicone rubber particles, acrylic rubber particles, urethane rubber particles, polyamide particles, polyamide-imide particles, polyimide particles, benzoguanamine particles, and core-shell particles thereof. Of these, polyamide particles, polyamide-imide particles, and polyimide particles are preferable.

The content of the organic filler is preferably 10 parts by weight and a preferable upper limit of 500 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the organic filler is in this range, the obtained cured product becomes more excellent in toughness and the like while maintaining excellent adhesiveness and the like. The more preferable lower limit of the content of the organic filler is 30 parts by weight, and the more preferable upper limit is 400 parts by weight.

The adhesive of the present invention contains an inorganic filler for the purpose of reducing the linear expansion coefficient after curing to reduce warpage, imparting flame retardancy, improving adhesive reliability, and the like. May be good.

Examples of the inorganic filler include silica such as colloidal silica, alumina, aluminum nitride, boron nitride, silicon nitride, aluminum hydroxide, magnesium hydroxide, glass powder, glass frit, glass fiber, carbon fiber, and inorganic ion exchange. The body etc. can be mentioned.

The content of the inorganic filler is preferably 10 parts by weight and a preferable upper limit of 1000 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the inorganic filler is in this range, the effect of improving the adhesive reliability while maintaining the excellent processability and the like becomes more excellent. The more preferable lower limit of the content of the inorganic filler is 20 parts by weight, and the more preferable upper limit is 900 parts by weight.

Further, the inorganic filler can also be used as a flow adjusting agent for the purpose of improving the coatability and shape retention on the adherend in a short time.

Examples of the inorganic filler used as the flow conditioner include fumed silica and layered silicate.

Regarding the content of the inorganic filler used as the flow conditioner, the preferable lower limit is 0.1 parts by weight and the preferable upper limit is 50 parts by weight with respect to 100 parts by weight of the curable resin. When the content of the inorganic filler used as the flow adjusting agent is within this range, the effect of improving the coatability and shape retention on the adherend in a short time becomes more excellent. The more preferable lower limit of the content of the inorganic filler used as the flow adjusting agent is 0.5 parts by weight, and the more preferable upper limit is 30 parts by weight.

The adhesive of the present invention may contain a polymer compound as long as the object of the present invention is not impaired. The polymer compound plays a role as a film-forming component.

The polymer compound may have a reactive functional group.
Examples of the reactive functional group include an amino group, a urethane group, an imide group, a hydroxyl group, a carboxyl group, an epoxy group and the like.

Further, the polymer compound may or may not form a phase-separated structure in the cured product. When the polymer compound does not form a phase-separated structure in the cured product, the polymer compound is excellent in mechanical strength at high temperature, long-term heat resistance, and moisture resistance, and therefore, as the reactive functional group. A polymer compound having an epoxy group is preferable.

The adhesive of the present invention may contain a reactive diluent as long as the object of the present invention is not impaired.
As the reactive diluent, a reactive diluent having two or more reactive functional groups in one molecule is preferable from the viewpoint of adhesive reliability.
Examples of the reactive functional group contained in the above-mentioned reactive diluent include those similar to the reactive functional group possessed by the above-mentioned polymer compound.

The adhesive of the present invention may further contain additives such as a solvent, a coupling agent, a dispersant, a storage stabilizer, an antibleeding agent, a flux agent, and a liquid flame retardant.

As a method for producing the adhesive of the present invention, for example, a curable resin and a curing agent of the present invention are added as necessary using a mixer such as a homodisper, a universal mixer, a Banbury mixer, or a kneader. Examples thereof include a method of mixing with other curing agents, curing accelerators and the like.
Further, by applying the adhesive of the present invention on the release film and drying it, an adhesive film made of the adhesive of the present invention can be obtained.

The adhesive of the present invention can be used for a wide range of applications, but can be suitably used for electronic material applications in which high heat resistance is particularly required. For example, it can be used as a die-attaching agent in aviation and in-vehicle electric control unit (ECU) applications, and in power device applications using SiC and GaN. Further, for example, it can be used as an adhesive for a power overlay package, an adhesive for a printed wiring board, an adhesive for a coverlay of a flexible printed circuit board, an adhesive for semiconductor bonding, an adhesive for a structural material, and the like. Further, in addition to adhesive applications, it can be used as a curable composition, for example, in a sealing agent, a copper-clad laminate, an adhesive for semiconductor bonding, an interlayer insulating film, a prepreg, and the like.

According to the present invention, it is possible to provide an imide oligomer that can be used for a cured product having excellent long-term heat resistance. Further, according to the present invention, it is possible to provide a curing agent composed of the imide oligomer and an adhesive made of the curing agent. Furthermore, according to the present invention, it is possible to provide a method for producing the imide oligomer.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Synthesis Example 1 (Preparation of Imide Oligomer A))
3-Aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) 32.74 parts by weight (1.5 equivalents with respect to the acid anhydride group of 3,4'-oxydiphthalic acid dianhydride to be reacted) N, N-dimethylformamide 200 mL Was dissolved in. 31.0 parts by weight of 3,4'-oxydiphthalic acid dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution, and the mixture was stirred at 25 ° C. for 2 hours to react to obtain an amic acid oligomer solution. The obtained amic acid oligomer solution was added to 2 L of 1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.5 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was heated at 180 ° C. for 2 hours and then reacted at 300 ° C. for 2 hours under imidization conditions to obtain an imide oligomer A having a phenolic hydroxyl group (imidization ratio 94%). ..
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer A contained the imide oligomer represented by the above formula (1-1) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer A contained 5.5% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer A was 506.

(Synthesis Example 2 (Preparation of Imide Oligomer B))
The imidization condition of the precipitate was the same as that of Synthesis Example 1 except that the imidization condition of the precipitate was changed to heating at 200 ° C. and 5 mmHg for 3 hours using a vacuum drying oven, and the imide oligomer B having a phenolic hydroxyl group (imidization). Rate 46%) was obtained.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer B contained the imide oligomer represented by the above formula (1-1). Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer B contained 5.5% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer B was 510.

(Synthesis Example 3 (Preparation of Imide Oligomer C))
The same as in Synthesis Example 1 except that the amount of 3-aminophenol used was changed to 65.48 parts by weight (3 equivalents with respect to the acid anhydride group of the 3,4′-oxydiphthalic anhydride to be reacted). , An imide oligomer C having a phenolic hydroxyl group (imidization ratio 94%) was obtained.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer C contained the imide oligomer represented by the above formula (1-1) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer C contained 4.7% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer C was 506.

(Synthesis Example 4 (Preparation of Imide Oligomer D))
32.74 parts by weight of 3-aminophenol with respect to 36.95 parts by weight of 5-amino-o-cresol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) (with respect to the acid anhydride group of 3,4'-oxydiphthalic acid dianhydride to be reacted. An imide oligomer D having a phenolic hydroxyl group (imidization ratio 94%) was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to 1.5 equivalents.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer D contained the imide oligomer represented by the above formula (1-1) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer D contained 5.3% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer D was 531.

(Synthesis Example 5 (Preparation of Imide Oligomer E))
Instead of 31.0 parts by weight of 3,4'-oxydiphthalic anhydride, 52.0 weight of 4,4'-(4,4'-isopropyridenediphenoxy) diphthalic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) An imide oligomer E having a phenolic hydroxyl group (imidization ratio 93%) was obtained in the same manner as in Synthesis Example 1 except that the portion was added. The amount of 3-aminophenol used is 1.5 equivalents with respect to the acid anhydride group of the 4,4'-(4,4'-isopropyridenediphenoxy) diphthalic anhydride to be reacted.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer E contained the imide oligomer represented by the above formula (1-1) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer E contained 5.4% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer E was 712.

(Synthesis Example 6 (Preparation of Imide Oligomer F))
34.45 parts by weight of 1,3-bis (2- (4-aminophenyl) -2-propyl) benzene (manufactured by Mitsui Chemicals Fine Co., Ltd., "bisaniline M") was dissolved in 200 mL of N, N-dimethylformamide. To the obtained solution, 104.1 parts by weight of 4,4'-(4,4'-isopropyridenediphenoxy) diphthalic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added, and the mixture was stirred at 25 ° C. for 2 hours for reaction. A solution of an amic acid oligomer (A) having an acid anhydride group at both ends was obtained. 32-74 parts by weight of 3-aminophenol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) in the obtained solution of the amic acid oligomer (A) (1.5 equivalents with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted) Was added, and the mixture was stirred at 25 ° C. for 2 hours to react to obtain a solution of the amic acid oligomer (B). The obtained solution of the amic acid oligomer (B) was added to 2 L of 1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.5 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was heated at 180 ° C. for 2 hours and then reacted at 300 ° C. for 2 hours under imidization conditions to obtain an imide oligomer F having a phenolic hydroxyl group (imidization ratio 92%). ..
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer F contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer F contained 5.5% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer F was 1548.

(Synthesis Example 7 (Preparation of Imide Oligomer G))
The amount of 1,3-bis (2- (4-aminophenyl) -2-propyl) benzene used was changed to 17.23 parts by weight, and the amount of 3-aminophenol used was changed to 49.11 parts by weight. An imide oligomer G having a phenolic hydroxyl group (imidization ratio 93%) was obtained in the same manner as in Synthesis Example 6 except for the above. The amount of 3-aminophenol used is 1.5 equivalents with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer G contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer G contained 5.4% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer G was 1126.

(Synthesis Example 8 (Preparation of Imide Oligomer H))
1,3-bis (2- (4-aminophenyl) -2-propyl) benzene (manufactured by Mitsui Chemical Fines, Inc., "bisaniline M") 34.5 parts by weight is N-methylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., "NMP") was dissolved in 200 mL. To the obtained solution, 104.1 parts by weight of 4,4'-(4,4'-isopropyridenediphenoxy) diphthalic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 25 ° C. for 2 hours for reaction. Amic acid oligomer solution (A) was obtained. Further, with respect to the obtained amic acid oligomer solution (A), 32.74 parts by weight of 3-aminophenol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) (1.5 with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted). Equivalent amount) was added, and the mixture was stirred at 25 ° C. for 2 hours to react to obtain an amic acid oligomer solution (B). The obtained solution of the amic acid oligomer (B) was added to 2 L of 1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.5 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was dissolved in 100 mL of N, N-dimethylformamide, and the obtained solution was added to 2 L of 0.1 mol / L hydrochloric acid to recover the precipitate. The obtained precipitate was heated at 180 ° C. for 2 hours and then reacted at 300 ° C. for 2 hours under imidization conditions to obtain an imide oligomer H having a phenolic hydroxyl group (imidization ratio 92%). ..
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer H contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer H contained 5.5% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer H was 2720.

(Synthesis Example 9 (Preparation of Imide Oligomer I))
Changed 34.45 parts by weight of 1,3-bis (2- (4-aminophenyl) -2-propyl) benzene to 25.83 parts by weight of 2,2-bis (3-amino-4-hydroxyphenyl) propane. An imide oligomer I having a phenolic hydroxyl group (imidization ratio 93%) was obtained in the same manner as in Synthesis Example 6 except for the above.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer I contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer I contained 5.4% of the imide oligomer having an ester bond. Furthermore, the number average molecular weight of the imide oligomer I was 1490.

(Synthesis Example 10 (Preparation of Imide Oligomer J))
The same as in Synthesis Example 1 except that the amount of 3-aminophenol used was changed to 21.83 parts by weight (1 equivalent with respect to the acid anhydride group of the 3,4'-oxydiphthalic anhydride to be reacted). , An imide oligomer J having a phenolic hydroxyl group (imidization rate 93%) was obtained.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer J contained the imide oligomer represented by the above formula (1-1) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer J contained 8.2% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer J was 543.

(Synthesis Example 11 (Preparation of Imide Oligomer K))
The imide oligomer K (imidization ratio 44%) was prepared in the same manner as in Synthesis Example 10 except that the imidization conditions of the precipitate were changed to heating at 200 ° C. and 5 mmHg for 3 hours using a vacuum drying oven. Obtained.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer K contained the imide oligomer represented by the above formula (1-1). Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer K contained 8.2% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer K was 556.

(Synthesis Example 12 (Preparation of Imide Oligomer L))
An imide oligomer L having a phenolic hydroxyl group (imidization ratio 92%) was obtained in the same manner as in Synthesis Example 6 except that the amount of 3-aminophenol used was changed to 21.83 parts by weight. The amount of 3-aminophenol used is 1 equivalent with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer L contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer L contained 8.0% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer L was 1710.

(Synthesis Example 13 (Preparation of Imide Oligomer M))
Similar to Synthesis Example 6, an imide oligomer having a phenolic hydroxyl group, except that the amount of 1,3-bis (2- (4-aminophenyl) -2-propyl) benzene used was changed to 17.23 parts by weight. M (imidization ratio 92%) was obtained. The amount of 3-aminophenol used is 1 equivalent with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer M contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC fractionation and FT-IR analysis, it was confirmed that the imide oligomer M contained 8.1% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer M was 1241.

(Synthesis Example 14 (Preparation of Imide Oligomer N))
Phenolic hydroxyl groups in the same manner as in Synthesis Example 9 except that the amount of 3-aminophenol used was changed to 21.83 parts by weight (1 equivalent with respect to the acid anhydride group of the amic acid oligomer (A) to be reacted). An imide oligomer N having an imidization ratio of 94% was obtained.
It was confirmed by ¹ H-NMR, GPC, and FT-IR analysis that the imide oligomer N contained the imide oligomer represented by the above formula (1-2) as a main component. Further, by GPC preparative and FT-IR analysis, it was confirmed that the imide oligomer N contained 8.4% of the imide oligomer having an ester bond. Further, the number average molecular weight of the imide oligomer N was 1571.

(Examples 1 to 9, Comparative Examples 1 to 5)
Each material was stirred and mixed according to the compounding ratios shown in Tables 1 and 2, and the adhesives of Examples 1 to 9 and Comparative Examples 1 to 5 were prepared.

<Evaluation>
The following evaluations were performed on each of the adhesives obtained in Examples and Comparative Examples. The results are shown in Tables 1 and 2.

(5% weight loss temperature)
Each of the adhesives obtained in Examples and Comparative Examples was applied onto a release film and dried to obtain an adhesive film having a thickness of 25 μm.
The obtained adhesive film was cured by heating at 190 ° C. for 1 hour, and the adhesive film was cured at 40 ° C. to 450 ° C. using a thermogravimetric measuring device (“EXTEAR TG / DTA6200” manufactured by SII Nanotechnology Co., Ltd.). The 5% weight loss temperature was measured under a temperature range of ° C. and a temperature rise condition of 10 ° C./min.

(Long-term heat resistance (adhesive strength))
50 μm-thick Kapton (registered trademark) was laminated on both sides of each of the adhesives obtained in Examples and Comparative Examples, cured and adhered by heating at 190 ° C. for 1 hour, and then cut into strips having a width of 1 cm. I got a test piece. The obtained test piece was heat-treated at 175 ° C. for 1000 hours. The adhesive strength of the test piece after the heat treatment was measured using a tensile tester (manufactured by ORIENTEC, "UCT-500") under the condition of a peeling speed of 20 mm / min.
When the adhesive strength is 3.4 N / cm or more, it is "○", when it is less than 3.4 N / cm, it is "△", when it is 2.4 N / cm or more, and it is less than 2.4 N / cm. The long-term heat resistance was evaluated as "x".

According to the present invention, it is possible to provide an imide oligomer that can be used for a cured product having excellent long-term heat resistance. Further, according to the present invention, it is possible to provide a curing agent composed of the imide oligomer and an adhesive made of the curing agent. Furthermore, according to the present invention, it is possible to provide a method for producing the imide oligomer.

Claims (5)

An imide oligomer composition containing an imide oligomer represented by the following formula (1-1) and / or an imide oligomer represented by the following formula (1-2) .
The content ratio of the imide oligomer having an ester bond is 7% or less, and the content ratio is 7% or less.
Imidization rate is 70% or more
An imide oligomer composition characterized by the above.

In formulas (1-1) and (1-2), R ¹ and R ² are independently hydrogen atoms, halogen atoms, or monovalent hydrocarbon groups that may be substituted, and X is used. Is a bond, an oxygen atom, or a optionally substituted divalent hydrocarbon group, and in formula (1-2), Y may be a bond, an oxygen atom, or a substituted hydrocarbon group. It is a divalent hydrocarbon group. The imide oligomer composition according to claim 1, wherein the number average molecular weight is 400 or more and 4200 or less. A curing agent comprising the imide oligomer composition according to claim 1 or 2 . An adhesive comprising a curable resin and the curing agent according to claim 3 . A step of reacting a compound represented by the following formula (3) with a compound represented by the following formula (2) to obtain an amic acid oligomer solution , and the obtained amic acid oligomer solution is added to an acid for precipitation. It has a process of collecting things ,
A method for producing an imide oligomer composition, wherein the amount of the monoamine having a phenolic hydroxyl group used is 1.5 equivalents or more with respect to the acid anhydride group of the compound having an acid anhydride group.

In formula (3), A is a tetravalent group represented by the following formula (4-1) or the following formula (4-2).

In formulas (4-1) and (4-2), * is a bond position, and in formula (4-1), Z is a bond, an oxygen atom, a carbonyl group, or even if substituted. It is often a divalent hydrocarbon group that may have an oxygen atom at the bond position. The hydrogen atom of the aromatic ring in the formulas (4-1) and (4-2) may be substituted.

In formula (2), Ar is a optionally substituted divalent aromatic group, and R ³ and R ⁴ are independently hydrogen atoms or optionally substituted monovalent hydrocarbon groups, respectively. Is.