JP2022053323A - Amorphous particles containing amide acid oligomer having imido groups, and production method thereof - Google Patents

Abstract

To provide: a production method allowing production of particles containing an amide acid oligomer in a less expensive and more convenient manner in far shorter time than the prior art; and particles containing an amide acid oligomer having novel physical properties and characteristics never found before.SOLUTION: Amorphous particles contain an imido group-containing amide acid oligomer (P) in which some of amide acid units in an amide acid oligomer (A) represented by general formula (2) are converted to imide rings with the imidization rate from 1% to 80% inclusive, where the average particle diameter measured when the particles are dispersed in water is in the range of 100-500 μm.SELECTED DRAWING: None

Description

The present invention relates to amorphous particles containing an amic acid oligomer having an imide group and a method for producing the same.

Aromatic polyimide has excellent moldability, has the highest level of heat resistance in a polymer system, and has excellent mechanical and electrical properties. Therefore, aircraft, space industry equipment, electrical and electronic equipment, etc. It is used as a material (heat-resistant composite material) in a wide range of fields such as general industrial applications and vehicle engine (peripheral) members. Therefore, there is a demand for a method capable of producing polyimide, which is a matrix resin, inexpensively, easily, and in a short time.

As a method for producing polyimide, Patent Document 1 describes a method for producing polyimide powder in which a polyamic acid solution is heat-treated to precipitate polyimide particles from a solvent, and the polyimide powder is directly collected from the solvent. In Patent Document 2, an aromatic tetracarboxylic acid component and an aromatic diamine component are reacted in a reaction solvent to precipitate fine particles, and then the reaction is continued while distilling off water to produce a polyimide powder. The method is described. In Patent Document 3, an NMP solution of a terminal-modified imide oligomer is poured into ion-exchanged water, and the precipitated solid content is filtered off to obtain a granular terminal-modified imide oligomer, and then the terminal-modified imide oligomer is pulverized. A production method for obtaining a terminally modified imide oligomer powder is described.

Further, there is also known a method of directly obtaining a polyimide molded body without isolating the polyimide powder by obtaining a polyamic acid powder and molding the powder. Patent Document 4 describes a method for producing a polyimide molded product, in which a polyamic acid is polymerized in a specific solvent, powders and granules are taken out from the suspension, and the powder or granular material is heat-molded to obtain a polyamic acid molded product, which is further imidized. Are listed.

It is also known that polyamic acid powder can be used as an adhesive. Patent Documents 5 and 6 describe that after preparing a solution of polyamic acid, powder of polyamic acid can be produced by a plurality of methods and used for bonding cold rolled steel.

Japanese Unexamined Patent Publication No. 7-33875 Japanese Unexamined Patent Publication No. 11-302380 WO 2018/180930 A1 Japanese Patent Application Laid-Open No. 7-118388 Japanese Patent Application Laid-Open No. 6-16811 Japanese Patent Laid-Open No. 6-1856

However, in the techniques described in Patent Documents 1 and 2, the polyamic acid is heated in a solution to prepare a polyimide solution, and then the polyimide particles are precipitated, recovered, washed, and dried to form a powdery polyimide. Is being manufactured. In the technique described in Patent Document 3, a powdery imide oligomer is produced by precipitating (precipitating) an imide oligomer in a solution with a poor solvent, recovering, washing, and drying. In the technique described in Patent Document 4, a suspension of polyamic acid is prepared in a specific solvent, and the polyamic acid is recovered, washed, and dried to produce powdered polyamic acid. In the techniques described in Patent Documents 5 and 6, in addition to the method similar to the above, a polyamic acid powder is produced by preparing a polyamic acid solution and then volatilizing the solvent.

Therefore, the techniques described in Patent Documents 1 to 4 have many steps and are complicated, and a long time (several hours) is required for manufacturing. Therefore, from the viewpoint of manufacturing polyimide inexpensively, easily and in a short time. , There is room for further improvement. Further, the technique described in Patent Documents 5 and 6 for producing a polyamic acid powder by volatilizing a solvent from a polyamic acid solution includes a polyamic acid having a very limited composition and a very limited variety. Only the combination with the solvent is exemplified, the versatility is completely unknown, and the use of the obtained polyamic acid is exemplified only for the adhesive, and the polyamide suitable for obtaining the molded product is exemplified. Its application to acids is completely unknown. In addition, a high boiling point aprotic solvent is used, which raises concerns about safety, and its application to other solvents is completely unknown.

One aspect of the present invention is a production method capable of producing amorphous particles (P) containing an amic acid oligomer having an imide group at a low cost, easily, and in an extremely short time as compared with the prior art. And an object thereof is to provide amorphous particles (P) containing the amic acid oligomer.

As a result of diligent studies to solve the above problems, the present inventor has made it possible to obtain an amorphous particle containing an amic acid oligomer (P) having an imide group inexpensively and easily by melt-processing the solution of the amic acid oligomer. The present invention has been found that it can be produced in an extremely short time (for example, several minutes), and that the obtained amic acid oligomer (P) having an imide group has novel physical properties and properties that have never been seen before. Has been completed.

That is, one embodiment of the present invention includes the following configurations.
[1] A part of the amid acid unit in the amid acid oligomer (A) represented by the following general formula (2) is converted into an imide ring, and the imidization rate is 1 to 80% (here, α to α to 80%). β represents α or more and β or less; the same applies hereinafter) and contains an amic acid oligomer (P) having an imide group.
Amorphous particles having an average particle diameter in the range of 100 to 500 μm measured by being dispersed in water.

(In general formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ may be the same or different from each other. Representing a good tetravalent aromatic tetracarboxylic acid residue, R ₅ and R ₆ are one of which is a hydrogen atom and the other of which is a phenyl group, where m and n are 1 ≦ m, 0 ≦ n, The relationship of 1 ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of repeating units may be block or random.)
[2] The amorphous particle according to [1], which contains 20% by weight or less of a solvent.
[3] The solvent is a mixed solvent of an alcohol-based solvent and an ether-based solvent, a single solvent of a hydroxy-ether-based solvent, a mixed solvent of an alcohol-based solvent and a hydroxy-ether-based solvent, and a mixture of an ether-based solvent and a hydroxy-ether-based solvent. The solvent or a mixed solvent of an alcohol-based solvent, an ether-based solvent, and a hydroxy-ether-based solvent, wherein the boiling point (in the mixed solvent, the boiling point of each single solvent) is 130 ° C. or lower, according to [2]. Atypical particles.
[4] The amorphous particle according to [3], wherein the solvent is a mixed solvent of methanol and 1,3-dioxolane.
[5] An imide group-containing amide in which a part of the amic acid unit in the amid acid oligomer (A) represented by the following general formula (2) is converted into an imide ring and the imidization rate is 0 to 1%. The method for producing an amorphous particle according to [1], which comprises a step of melting and processing a solution of the acid oligomer (P).

(In general formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ may be the same or different from each other. Representing a good tetravalent aromatic tetracarboxylic acid residue, R ₅ and R ₆ are one of which is a hydrogen atom and the other of which is a phenyl group, where m and n are 1 ≦ m, 0 ≦ n, The relationship of 1 ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of repeating units may be block or random.)
[6] The method for producing amorphous particles according to [5], wherein the melting process is performed at a temperature of 250 ° C. or lower.
[7] The method for producing amorphous particles according to [6], which uses an extruder during melt processing.
[8] The method for producing amorphous particles according to [7], wherein the residence time in the extruder is 1 to 30 minutes.

According to one aspect of the present invention, it is not necessary to precipitate (precipitate) or pulverize the amic acid oligomer (P) having an imide group with a poor solvent. Therefore, it is possible to produce amorphous particles containing an amic acid oligomer (P) having an imide group, which is excellent in handleability, inexpensively, easily, and in an extremely short time (several minutes) as compared with the prior art. It is possible to provide an amorphous particle containing an amic acid oligomer (P) having an imide group having a novel physical property and characteristics which has never been seen before.

This is an example of observing amorphous particles with an optical microscope.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to this, and various modifications can be made within the scope described, and the present invention can be obtained by appropriately combining the technical means disclosed in different embodiments and examples. The form is also included in the technical scope of the present invention. In the present specification, unless otherwise specified, "A to B" representing a numerical range means "A or more (including A and larger than A), B or less (including B and smaller than B)". do. Also, "weight" and "mass" are used as synonyms.

[1. Amorphous particles containing an amic acid oligomer (P) having an imide group]
In one embodiment of the present invention, the amorphous particles containing the amic acid oligomer (P) having an imide group are amorphous particles, and each particle has a sharp portion (not spherical). Whether or not a particle is an "atypical particle" can be easily determined, for example, by observing it with an optical microscope.

The amorphous particles containing the imide group-containing amic acid oligomer (P) of the present invention contain the imide group-containing amid acid oligomer (P) as an essential component, and further, as an optional component, an imide oligomer (B) and a solvent ( C) and other components may be included. Among them, it is preferable to contain either the imide oligomer (B) or the solvent (C), and it is more preferable to contain the imide oligomer (B) and the solvent (C).
The amic acid oligomer (P) having an imide group and the imide oligomer (B) do not have to be chemically compatible, but are preferably chemically compatible. That is, the amic acid oligomer (P) having an imide group is preferably a precursor of the imide oligomer (B), and the imide oligomer (B) is a chemical reaction (imidization) from the amid acid oligomer (P) having an imide group. ) Is preferable.

The amide acid oligomer (P) having an imide group is obtained by converting a part of the amide acid unit in the amide acid oligomer (A) represented by the above general formula (2) into an imide ring. That is, the amic acid oligomer (A) is different from the amid acid oligomer (P) having an imide group.
The proportion of the imide ring converted from the amic acid unit can be expressed by the imidization rate.
The imidization rate of the amic acid oligomer (P) having ^an imide group can be calculated by measuring the peak area derived from the aromatic 1H and the peak area derived from the residual amide 1H by ¹ H ^- NMR. .. The imidization ratio (Rp) of the amic acid oligomer (P) having an imide group of the present invention is 1 to 80%, preferably 3 to 60%, and more preferably 5 to 40%.

In other words, in the amic acid oligomer (P) having an imide group, the number of moles of the amic acid unit and the imide ring unit in one molecule has the following relationship.
0.01 ≤ (number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amide acid unit) ≤ 0.80
Preferably, in the amic acid oligomer (P) having an imide group, the number of moles of the amic acid unit and the imide ring unit in one molecule has the following relationship.
0.03 ≤ (number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amide acid unit) ≤ 0.60
More preferably, in the amic acid oligomer (P) having an imide group, the number of moles of the amic acid unit and the imide ring unit in one molecule has the following relationship.
0.05 ≤ (number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amide acid unit) ≤ 0.40

In the present invention, it is necessary that the amic acid oligomer (P) having an imide group has an imidization ratio (Rp) in a specific range as described above in order to exert the effect of the present invention. When the imidization ratio (Rp) is less than 1%, problems such as liquid dripping and air bubbles may occur due to the excessively high fluidity. When the imidization ratio (Rp) exceeds 80%, the fluidity is too low, and the moldability may be inferior. Further, in the present invention, it is considered that the imide group of the amic acid oligomer (P) having an imide group contributes to providing a molded product having excellent mechanical properties, for example, elongation at break.

The amic acid oligomer (P) can secure molding fluidity even when the imidization ratio (Rp) is more than 60% and less than 80%, but when higher molding fluidity is required, The imidization ratio (Rp) is preferably 60% or less, more preferably 40% or less.

Further, when the imidization rate (Rp) is low, for example, when a thick molded product is to be imidized and molded at the same time, the water generated by the imidization may be difficult to escape and bubbles may be formed. Therefore, the imidization ratio (Rp) is preferably 3% or more, and more preferably 5% or more.

Further, the imidization ratio (Rp) needs to be appropriately set depending on the properties of the molded product and the molding conditions. For example, when imidizing and molding a thick molded product at the same time, the imidization ratio (Rp) is preferably 5% or more and less than 80%, and 10% or more and less than 80%. Is more preferable. Further, for example, in order to obtain a molded product having excellent breaking elongation in terms of its mechanical properties, the imidization ratio (Rp) is preferably 5% or more and 50% or less, and 10% or more and 40% or less. Is more preferable.

The imidization ratio (Rp) of the amic acid oligomer (P) having an imide group can be controlled by controlling the temperature and time of the melt processing. It can also be adjusted by blending an amic acid oligomer (P) having a plurality of types of imide groups having different imidization ratios. The method for measuring the imidization rate will be described in detail in Examples.

When the amorphous particles containing the amide acid oligomer (P) having an imide group of the present invention contain the imide oligomer (B), the amide acid oligomer (P) having an imide group and the imide oligomer (B) It is preferable that (P) is 50 wt% or more and less than 100 wt%, where the total of and is 100 wt%.

Further, the imidization ratio (Rpb) in consideration of all the imide units and the amidic acid units of the amic acid oligomer (P) having an imide group and the imide oligomer (B) is preferably 1 to 80%. In other words, in the amorphous particles containing the amic acid oligomer (P) having an imide group and the imide oligomer (B), the number of moles of all the amic acid units and the imide ring unit may be as follows. preferable.
0.01 ≤ (number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amide acid unit) ≤ 0.80

When the chemically compatible amic acid oligomer (P) and imide oligomer (B) coexist, the amide acid oligomer (P) softens and flows at a lower temperature than the imide oligomer (B), so that the amide A relatively small amount of acid oligomer (for example, the imidization ratio (Rpb) considering all the imide units and amidic acid units of the amid acid oligomer (P) having an imide group and the imide oligomer (B) is 50%. It is possible to secure the molding fluidity even in the region of more than 80% or less). However, when the imidization ratio (Rpb) exceeds 80%, the moldability may be inferior. Further, when the imidization rate (Rpb) is low, for example, when a thick molded product is to be imidized and molded at the same time, the water generated by the imidization may be difficult to escape and bubbles may be formed. Therefore, it is necessary to appropriately set it according to the properties of the molded body and the molding conditions. For example, when imidizing and molding a thick molded product at the same time, the imidization ratio (Rpb) is preferably 5% or more and less than 80%, and 10% or more and less than 80%. Is more preferable. Further, for example, when trying to obtain a molded product having excellent breaking elongation in terms of its mechanical properties, the imidization ratio (Rpb) is preferably 5% or more and 50% or less, and is preferably 10% or more and 40% or less. Is more preferable.

The amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention may be a mixture of amid acid oligomers having imide groups having different molecular weights. Further, it may be a mixture of amic acid oligomers having imide groups having different monomer compositions. In these cases, it is preferable that the imide oligomers (B1, B2 ...) Chemically corresponding to the amic acid oligomers (P1, P2 ...) having their respective imide groups are contained.

The molecular weight (weight average molecular weight) of the soluble polymer component (for example, the amic acid oligomer (P) and the imide oligomer (B) having an imide group) contained in the amorphous particles containing the amic acid oligomer (P) having an imide group is , Can be confirmed by GPC. The molecular weight is preferably 1000 to 100,000, more preferably 3,000 to 50,000, and even more preferably 5,000 to 30,000. The molecular weight of the amic acid oligomer (P) having an imide group can be controlled by controlling the temperature and time of the melt processing. The molecular weight measurement conditions are set by GPC so as to be optimal according to the structure of the oligomer in the amorphous particles containing the amic acid oligomer (P) having an imide group to be measured.

The average particle size of the atypical particles containing the amic acid oligomer (P) having an imide group can be measured by dispersing the atypical particles containing the amic acid oligomer (P) having the imide group in water. can. The average particle size is preferably in the range of 10 to 500 μm, more preferably in the range of 10 to 300 μm, and even more preferably in the range of 20 to 100 μm. Further, the particle size distribution (D50) is preferably in the range of 100 to 500 μm. The method for measuring the average particle size will be described in detail in Examples.

The minimum melt viscosity of the amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention is preferably 20000 Pa · sec or less, and more preferably 10,000 Pa · sec or less. It is more preferably 5000 Pa · sec or less, and particularly preferably 3000 Pa · sec or less. The minimum melt viscosity of the amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention is preferably 1 to 20000 Pa · sec, but is not limited to this range. When the minimum melt viscosity is within the above range, the amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention are more excellent in moldability. In the present specification, the minimum melt viscosity refers to a value measured by the method described in Examples described later.

The melt viscosity of the amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention at 280 ° C. is preferably 200 to 1000000 Pa · sec, preferably 200 to 800,000 Pa · sec. More preferably, it is more preferably 200 to 500,000 Pa · sec. If the melt viscosity at 280 ° C. exceeds 1,000,000 Pa · sec, it tends to be difficult to flow. Therefore, when producing a fiber-reinforced composite material, it is difficult for the amic acid oligomer (P) having an imide group to be impregnated between the fibers, and defects such as voids or non-impregnated portions are reduced or eliminated. Tends to be difficult to obtain. Further, when the melt viscosity at 280 ° C. is less than 200 Pa · sec, the resin tends to flow too easily and it tends to be difficult to produce a prepreg, and as a result, it may be difficult to secure the drape property as the prepreg. In the present specification, the melt viscosity at 280 ° C. refers to a value measured by the method described in Examples described later.

In the amic acid oligomer (P) having an imide group in one embodiment of the present invention, a part of the amide acid unit in the amide acid oligomer (A) represented by the following general formula (2) is converted into an imide ring. The imidization rate (Rp) is 1 to 80%.

[2. Amidoacid oligomer with imide group (P)]
Hereinafter, in the present specification, "amide acid oligomer" is used as a synonym for "terminally modified amid acid oligomer" unless otherwise specified.
In the amide acid oligomer (P) having an imide group of the present invention, a part of the amide acid unit in the amide acid oligomer (A) represented by the following general formula (2) is converted into an imide ring, and the imide is used. It is an amic acid oligomer having an imide group having a conversion (Rp) of 1 to 80%.

(In general formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ may be the same or different from each other. Representing a good tetravalent aromatic tetracarboxylic acid residue, R ₅ and R ₆ are one of which is a hydrogen atom and the other of which is a phenyl group, where m and n are 1 ≦ m, 0 ≦ n, The relationship of 1 ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of repeating units may be block or random.)

In one embodiment of the present invention, in the general formula (2), the divalent aromatic diamine residue represented by R ₁ and R ₂ is present between the two amino groups of the aromatic diamines. Refers to aromatic organic groups. Further, in one embodiment of the present invention, in the general formula (2), the tetravalent aromatic tetracarboxylic acid residues represented by R ₃ and R ₄ are the four carbonyls of the aromatic tetracarboxylic acid. Refers to aromatic organic groups existing between groups. Here, the aromatic organic group is an organic group having an aromatic ring. The aromatic organic group is preferably an organic group having 4 to 30 carbon atoms, more preferably an organic group having 4 to 18 carbon atoms, and further preferably an organic group having 4 to 12 carbon atoms. .. The aromatic organic group is preferably a group containing 6 to 30 carbon atoms and hydrogen, more preferably a group containing 6 to 18 carbon atoms and hydrogen, and more preferably 6 carbon atoms. It is more preferably a group containing up to 12 carbons and hydrogen. The divalent aromatic diamine residues represented by R ₁ and R ₂ may be the same as each other or may be different from each other. Further, the divalent aromatic diamine residue represented by R ₁ and R ₂ may be a different aromatic diamine residue for each repeating unit.

Specific examples of the divalent aromatic diamine residue represented by R ₁ and R ₂ include 2-phenyl-4,4'-diaminodiphenyl ether (Ph-ODA) and 9,9-bis (Ph-ODA). At least one selected from 4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, 1,3-diaminobenzene, 4-phenoxy-1,3-diaminobenzene. It is more preferable to have.

The amic acid oligomer (A) represented by the general formula (2) is, for example, an amic acid oligomer using 2-phenyl-4,4'-diaminodiphenyl ether, and may be synthesized by the following method. More preferred. That is, the amide oligomer (A) represented by the general formula (2) is
(i) 1,2,4,5-benzenetetracarboxylic acids (particularly their acid dianhydrides), 3,3', 4,4'-biphenyltetracarboxylic acids (particularly their acid dianhydrides), and One or more tetracarboxylic acids selected from the group consisting of bis (3,4-carboxyphenyl) ethers (particularly their acid dianhydrides), and
(ii) Aromatic diamines containing 2-phenyl-4,4'-diaminodiphenyl ether,
(iii) 4- (2-Phenylethynyl) phthalic anhydride (PEPA), which is an unsaturated acid anhydride for introducing an unsaturated terminal group into an amic acid oligomer, and
Is more preferably synthesized by charging so that the total amount of the dicarboxylic acid group and the total amount of the primary amino group are approximately equal to each other and reacting in the presence (or absence) of an organic solvent.

When a plurality of dicarboxylic acid groups are adjacent to each other, "the number of carboxyl groups ÷ 2" is defined as "the number of dicarboxylic acid groups". For example, it is assumed that two dicarboxylic acid groups are contained in the structure "COOH-COOH-COOH-COOH".

In the amic acid oligomer (A) thus synthesized, R ₃ and R ₄ are independently selected from the tetravalent aromatic tetracarboxylic acid residues derived from one or more of the above aromatic tetracarboxylic acids. They may be the same as each other or different from each other. Further, in the case of 1 <m and 1 <n (m and n are integers), R ₃ (or R ₄ ) of each repeating unit may be the same as each other or may be different from each other. Further, in the case of 1 <m, one of a repeating unit in which R ₅ is a phenyl group and R ₆ is a hydrogen atom, and a repeating unit in which R ₅ is a hydrogen atom and R ₆ is a phenyl group. Or both may be optionally included.

In the general formula (2), m and n satisfy the relationships of 1 ≦ m, 0 ≦ n, 1 ≦ m + n ≦ 20, and 0.05 ≦ m / (m + n) ≦ 1.
The amic acid oligomer (P) having an imide group in one embodiment of the present invention may be 1 ≦ m ≦ 5, 0 <n ≦ 5, or 1 <m + n ≦ 10. It may be 0.5 ≦ m / (m + n) <1. Further, the amic acid oligomer (P) having an imide group in one embodiment of the present invention is more preferably 4 ≦ m + n, further preferably 5 ≦ m + n. When m and n satisfy the above relationship, the amic acid oligomer (P) having an imide group in one embodiment of the present invention is more excellent in storage stability of the solution, and the polyimide obtained by curing is heat resistant. Further excellent in sex and mechanical strength. In addition, m and n can be easily adjusted by controlling the type, molar ratio, etc. of the tetracarboxylic acids and aromatic diamines used as raw materials.

As used herein, the phrase "the sequence of the repeating unit may be either block or random" is intended to mean that the portion of the repeating unit may be a block polymer or a random polymer. ..

The amide acid oligomer (P) having an imide group is more preferably an amide acid oligomer having an amide bond in the main chain, and (i) 4- (2-phenylethynyl) at the ends (more preferably both ends). ) It has an additive-polymerizable unsaturated terminal group derived from phthalic anhydride, (ii) satisfies the relationship of 1 ≦ m + n ≦ 20, and (iii) is solid at room temperature (for example, 23 ° C.).

Examples of the 1,2,4,5-benzenetetracarboxylic acids include 1,2,4,5-benzenetetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA), and the like. And acid derivatives (esters, salts, etc.) of 1,2,4,5-benzenetetracarboxylic acid. Of these, 1,2,4,5-benzenetetracarboxylic acid dianhydride is more preferable.

Examples of the 3,3', 4,4'-biphenyltetracarboxylic acid are 3,3', 4,4'-biphenyltetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid di. Examples thereof include anhydrate (s-BPDA) and acid derivatives (esters, salts, etc.) of 3,3', 4,4'-biphenyltetracarboxylic acid. Of these, 3,3', 4,4'-biphenyltetracarboxylic dianhydride is more preferable.

Examples of the bis (3,4-carboxyphenyl) ethers include bis (3,4-carboxyphenyl) ether, bis (3,4-carboxyphenyl) ether dianhydride (s-ODPA), and bis (3,4-carboxyphenyl) ethers. Examples thereof include acid derivatives (esters, salts, etc.) of 3,4-carboxyphenyl) ethers. Of these, bis (3,4-carboxyphenyl) ether dianhydride is more preferred.

In one embodiment of the invention, R ₃ and / or R ₄ are 1,2,4,5-benzenetetracarboxylic acids, 3,3', 4,4'-biphenyltetracarboxylic acids, and bis (3). , 4-Carvophenyl) It may have a structure derived from aromatic tetracarboxylic acids other than ethers. That is, the amic acid oligomer (P) having an imide group is used as 1,2,4,5-benzenetetracarboxylic acids, 3,3', 4,4'-biphenyltetracarboxylic acids, and bis (3,4-). Carboxyphenyl) Other aromatic tetracarboxylic acids other than ethers may be added to the raw material and synthesized (using as a monomer). Examples of such other aromatic tetracarboxylic acids include 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), 2,3,3', 4'-biphenyltetracarboxylic acid. Dianoxide (a-BPDA), 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride (i-BPDA), 2,2-bis (3,4-dicarboxyphenyl) methane dianhydride , Bis (3,4-carboxyphenyl) ether dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride and the like. As the other aromatic tetracarboxylic acids, only one kind may be used, or two or more kinds may be used in combination.

Further, the amic acid oligomer (P) having an imide group can be synthesized by adding (using as a monomer) other aromatic diamines other than 2-phenyl-4,4'-diaminodiphenyl ether to the raw material. good. Examples of such other aromatic diamines include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 2,6-diethyl-1,3-diaminobenzene, 4, 6-diethyl-2-methyl-1,3-diaminobenzene, 3,5-diethyltoluene-2,6-diamine, 4,4'-diaminodiphenyl ether (4,4'-ODA), 3,4'-diamino Diphenyl ether (3,4'-ODA), 3,3'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, Bis (2,6-diethyl-4-aminophenyl) methane, 4,4'-methylene-bis (2,6-diethylaniline), bis (2-ethyl-6-methyl-4-aminophenyl) methane, 4 , 4'-Methylene-bis (2-ethyl-6-methylaniline), 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 1,3-bis ( 4-Aminophenoxy) Benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, benzidine, 3, 3'-dimethylbenzidine, 2,2-bis (4-aminophenoxy) propane, 2,2-bis (3-aminophenoxy) propane, 2,2-bis [4'-(4''-aminophenoxy) phenyl ] Hexafluoropropane, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene and the like can be mentioned. Among the above, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, and 1,3-diaminobenzene are other aromatic diamines. More preferable as a class. As the other aromatic diamines, only one kind may be used, or two or more kinds may be used in combination.

In particular, in applications where mechanical strength is required, (i) 2-phenyl-4,4'-diaminodiphenyl ether and (ii) other aromatic diamines are used in combination in the synthesis of the amic acid oligomer. Is preferable. In this case, the amount of the other aromatic diamines used is preferably more than 0 and 50 mol% or less, and more than 0 and 25 mol% or less, with the total amount of the aromatic diamines being 100 mol%. It is more preferable, and it is more preferable that it exceeds 0 and is 10 mol% or less. Other aromatic diamines used at this time include 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, and 1,3-diamino. One or more selected from benzene is preferable.

Similarly, in applications where mechanical strength is required, 0.50 ≦ m / (m + n) <1 is preferable, and 0.75 ≦ m / (m + n) <1 in the general formula (1). It is more preferably 0.90 ≦ m / (m + n) <1, and even more preferably 0.90 ≦ m / (m + n) ≦ 0.95.

Such an amic acid oligomer is excellent in handleability, has high solubility, and has high mechanical properties.

As the unsaturated acid anhydride for end modification (end cap), it is preferable to use 4- (2-phenylethynyl) phthalic anhydride. When synthesizing the amic acid oligomer, 4- (2-phenylethynyl) phthalic anhydride is preferably used in the range of 5 to 200 mol% with the total amount of aromatic tetracarboxylic acids as 100 mol%, and 5 to 150 mol. It is more preferable to use it at a ratio within the range of%.

[3. Imid oligomer (B)]
The amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention may contain the imide oligomer (B) represented by the following general formula (1) as an optional component. good. It is preferable that the imide oligomer (B) and the amide acid oligomer (P) or the amide acid oligomer (A) having an imide group chemically correspond to each other. That is, the imide oligomer (B) is preferably produced by a chemical reaction (imidization) from the amic acid oligomer (P) having an imide group or the amid acid oligomer (A).

Here, the imide oligomer (B) is different from the amic acid oligomer (P) having an imide group. That is, in the imide oligomer (B), a part of the imide unit in the imide oligomer (B) represented by the following general formula (1) may be converted into an amic acid unit, and the imidization rate (Rb) may be high. It is more than 80% and less than 100%. Preferably, the imidization rate is 90% or more and 100% or less.

In other words, in the imide oligomer (B), the number of moles of the amic acid unit and the imide ring unit in one molecule has the following relationship.
0.80 <(number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amic acid unit) ≤ 1.00
Preferably, in the imide oligomer (B), the number of moles of the amic acid unit and the imide ring unit in one molecule has the following relationship.
0.90 ≤ (number of moles of imide ring unit) / (number of moles of imide ring unit + number of moles of amide acid unit) ≤ 1.00

In the present specification, "imide oligomer" is used as a synonym for "terminally modified imide oligomer" unless otherwise specified.

(In the general formula (1), the sequences of R ₁ and R ₂ , R ₃ and R ₄ , R ₅ and R ₆ , m and n, and the repeating unit are the same as those in the general formula (2).)
In one embodiment of the present invention, the divalent aromatic diamine residues represented by R ₁ and R ₂ in the general formula (1) are the same as those in the general formula (2). Further, in one embodiment of the present invention, the tetravalent aromatic tetracarboxylic acid residues represented by R ₃ and R ₄ in the general formula (1) are the same as those in the general formula (2).

The divalent aromatic diamine residue represented by R ₁ and R ₂ is, as in the general formula (2), specifically, for example, 2-phenyl-4,4'-diaminodiphenyl ether (Ph-). ODA), 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, 1,3-diaminobenzene, 4-phenoxy-1,3-diamino More preferably, it is at least one selected from benzene.

The imide oligomer (B) represented by the general formula (1) is, for example, an imide oligomer using 2-phenyl-4,4'-diaminodiphenyl ether, and is derived from the corresponding (A) by imidization. It is preferable to have.

In the imide oligomer (B) thus derived, R ₃ and R ₄ are the same as in the general formula (2).

In the general formula (2), m and n are the same as the general formula (2).

The imide oligomer is more preferably an imide oligomer having an imide bond in the main chain, and (i) addition polymerization derived from 4- (2-phenylethynyl) phthalic anhydride at the ends (more preferably both ends). It has a possible unsaturated terminal group, (ii) satisfies the relationship of 1 ≦ m + n ≦ 20, and (iii) is solid at room temperature (eg, 23 ° C.).

Examples of the 1,2,4,5-benzenetetracarboxylic acids include 1,2,4,5-benzenetetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA), and the like. And acid derivatives (esters, salts, etc.) of 1,2,4,5-benzenetetracarboxylic acid. Of these, 1,2,4,5-benzenetetracarboxylic acid dianhydride is more preferable. When R ₃ and R ₄ are 1,2,4,5-benzenetetracarboxylic acids, the imide oligomer is represented by the following general formula (1-2). In the general formula (1-2), the definitions of R ₁ , R ₂ , R ₅ , R ₆ , m and n are the same as the definitions in the general formula (1).

Examples of the 3,3', 4,4'-biphenyltetracarboxylic acid are 3,3', 4,4'-biphenyltetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid di. Examples thereof include anhydrate (s-BPDA) and acid derivatives (esters, salts, etc.) of 3,3', 4,4'-biphenyltetracarboxylic acid. Of these, 3,3', 4,4'-biphenyltetracarboxylic dianhydride is more preferable. When R ₃ and R ₄ are 3,3', 4,4'-biphenyltetracarboxylic acids, the imide oligomer is represented by the following general formula (1-3). In the general formula (1-3), the definitions of R ₁ , R ₂ , R ₅ , R ₆ , m and n are the same as the definitions in the general formula (1).

Examples of the bis (3,4-carboxyphenyl) ethers include bis (3,4-carboxyphenyl) ether, bis (3,4-carboxyphenyl) ether dianhydride (s-ODPA), and bis (3,4-carboxyphenyl) ethers. Examples thereof include acid derivatives (esters, salts, etc.) of 3,4-carboxyphenyl) ethers. Of these, bis (3,4-carboxyphenyl) ether dianhydride is more preferred. When R ₃ and R ₄ are bis (3,4-carboxyphenyl) ethers, the imide oligomer is represented by the following general formula (1-4). In the general formula (1-4), the definitions of R ₁ , R ₂ , R ₅ , R ₆ , m and n are the same as the definitions in the general formula (1).

In one embodiment of the invention, R ₃ and / or R ₄ are 1,2,4,5-benzenetetracarboxylic acids, 3,3', 4,4'-biphenyltetracarboxylic acids, and bis (3). , 4-Carvophenyl) It may have a structure derived from aromatic tetracarboxylic acids other than ethers. That is, the above-mentioned imide oligomer is used in a method other than 1,2,4,5-benzenetetracarboxylic acids, 3,3', 4,4'-biphenyltetracarboxylic acids, and bis (3,4-carboxyphenyl) ethers. Other aromatic tetracarboxylic acids may be added to the raw material and synthesized (using it as a monomer). Examples of such other aromatic tetracarboxylic acids include 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), 2,3,3', 4'-biphenyltetracarboxylic acid. Dianoxide (a-BPDA), 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride (i-BPDA), 2,2-bis (3,4-dicarboxyphenyl) methane dianhydride , Bis (3,4-carboxyphenyl) ether dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride and the like. As the other aromatic tetracarboxylic acids, only one kind may be used, or two or more kinds may be used in combination.

Further, the amic acid oligomer (A) that induces the imide oligomer (B) is added to a raw material (using as a monomer) other aromatic diamines other than 2-phenyl-4,4'-diaminodiphenyl ether. It may be synthesized. Examples of such other aromatic diamines include 1,4-diaminobenzene, 1,3-diaminobenzene, 1,2-diaminobenzene, 2,6-diethyl-1,3-diaminobenzene, 4, 6-diethyl-2-methyl-1,3-diaminobenzene, 3,5-diethyltoluene-2,6-diamine, 4,4'-diaminodiphenyl ether (4,4'-ODA), 3,4'-diamino Diphenyl ether (3,4'-ODA), 3,3'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, Bis (2,6-diethyl-4-aminophenyl) methane, 4,4'-methylene-bis (2,6-diethylaniline), bis (2-ethyl-6-methyl-4-aminophenyl) methane, 4 , 4'-Methylene-bis (2-ethyl-6-methylaniline), 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 1,3-bis ( 4-Aminophenoxy) Benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, benzidine, 3, 3'-dimethylbenzidine, 2,2-bis (4-aminophenoxy) propane, 2,2-bis (3-aminophenoxy) propane, 2,2-bis [4'-(4''-aminophenoxy) phenyl ] Hexafluoropropane, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene and the like can be mentioned. Among the above, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, and 1,3-diaminobenzene are other aromatic diamines. More preferable as a class. As the other aromatic diamines, only one kind may be used, or two or more kinds may be used in combination.

In particular, in applications where mechanical strength is required, (i) 2-phenyl-4,4'-diaminodiphenyl ether and (ii) other aromatic diamines are used in combination in the synthesis of the amic acid oligomer. Is preferable. In this case, the amount of the other aromatic diamines used is preferably more than 0 and 50 mol% or less, and more than 0 and 25 mol% or less, with the total amount of the aromatic diamines being 100 mol%. It is more preferable, and it is more preferable that it exceeds 0 and is 10 mol% or less. Other aromatic diamines used at this time include 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4- (4-aminophenoxy) phenyl) fluorene, and 1,3-diamino. One or more selected from benzene is preferable.

Similarly, in applications where mechanical strength is required, 0.50 ≦ m / (m + n) <1 is preferable, and 0.75 ≦ m / (m + n) <1 in the general formula (1). It is more preferably 0.90 ≦ m / (m + n) <1, and even more preferably 0.90 ≦ m / (m + n) ≦ 0.95.

Such an amic acid oligomer is excellent in handleability, has high solubility, and has high mechanical properties.

As the unsaturated acid anhydride for end modification (end cap), it is preferable to use 4- (2-phenylethynyl) phthalic anhydride. When synthesizing the amic acid oligomer, 4- (2-phenylethynyl) phthalic anhydride is preferably used in the range of 5 to 200 mol% with the total amount of aromatic tetracarboxylic acids as 100 mol%, and 5 to 150 mol. It is more preferable to use it at a ratio within the range of%.

[4. solvent〕
The particles containing the amic acid oligomer (P) may contain the solvent (C) as an optional component. The content (residual solvent) of the solvent (C) in the particles containing the amic acid oligomer (P) is preferably 20% by weight or less, more preferably 10% by weight or less, and 8% by weight or less. It is more preferable to have.
The solvent is not particularly limited, and examples thereof include the solvent used at the time of synthesizing the amic acid oligomer.

For example, a solvent containing one or more solvents selected from the group consisting of an alcohol solvent, an ether solvent, and a hydroxy ether solvent can be mentioned.

Further, for example, a mixed solvent of an alcohol-based solvent and an ether-based solvent; a single solvent of a hydroxy-ether-based solvent; a mixed solvent of an alcohol-based solvent and a hydroxy-ether-based solvent; a mixed solvent of an ether-based solvent and a hydroxy-ether-based solvent; Alternatively, a mixed solvent of an alcohol solvent, an ether solvent and a hydroxy ether solvent; may be mentioned. Further, these solvents have a boiling point (boiling point of each single solvent in the mixed solvent) of 130 ° C. or lower regardless of whether they are used as a single solvent or a mixed solvent. preferable. Among these, a mixed solvent of methanol and 1,3-dioxolane is more preferable.

The solvent content can be measured by heating the particles containing the amic acid oligomer with DSC to a vicinity of the glass transition temperature (Tg) to soften the particles and volatilize the solvent incorporated therein. That is, in the present specification, the solvent content (residual solvent) refers to a value calculated from the weight reduction rate of the particles containing the amic acid oligomer in the vicinity of the glass transition temperature in TGA-DSC.

[5. Other additives]
The amorphous particles containing the amic acid oligomer (P) having an imide group according to the embodiment of the present invention may be mixed with other soluble polyimide or thermoplastic polyimide. The above-mentioned thermoplastic polyimide is a polyimide that becomes soft by heating, and although commercially available products can be mentioned, it is not particularly limited.

[6. Imidized / cured product]
The 5% weight loss temperature in air of the polyimide resin obtained by imidizing and curing amorphous particles containing an amic acid oligomer (P) having an imide group in one embodiment of the present invention is 520 ° C. or higher. It is preferably 530 ° C. or higher, more preferably 535 ° C. or higher, and even more preferably 535 ° C. or higher. The 5% weight loss temperature in air is considered to correlate with the oxidative deterioration rate when the polyimide resin is used for a long period of time in a high temperature environment. The higher the 5% weight loss temperature in air, the longer the polyimide resin can be used in a high temperature environment. That is, it can be said that the higher the 5% weight loss temperature in the air, the better the heat resistance stability for a long period of time. The 5% weight loss temperature in air refers to a value measured by the method described in Examples described later.

The amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention can be formed into, for example, a film-shaped polyimide by pressing, heating and melting, imidizing and curing. .. This film has the advantages of being able to obtain a fiber-reinforced composite material that has unprecedented new physical properties and properties, is excellent in handleability, is excellent in moldability, and exhibits excellent heat resistance and mechanical properties. Have.

Atypical particles containing an amic acid oligomer (P) having an imide group are used for sliding of aircraft, space industry equipment, engine (peripheral) members for vehicles, transport arms, robot arms, roll materials, friction materials, bearings, etc. It can be used in a wide range of fields where ease of moldability and high heat resistance are required, including general industrial applications such as dynamic members. Examples of aircraft members include engine fan cases, inner frames, moving blades (fan blades, etc.), stationary blades (structural guide blades (SGV), etc.), bypass ducts, various pipes, and the like. Examples of the vehicle member include a brake member, an engine member (cylinder, motor case, air box, etc.), an energy regeneration system member, and the like.

[7. Method for producing amorphous particles containing an amic acid oligomer (P) having an imide group]
The amic acid oligomer (P) having an imide group can be synthesized by the following method, to give a specific example.
1. 1. (i) 3,3', 4,4'-biphenyltetracarboxylic acids (particularly this acid dianhydride), 1,2,4,5-benzenetetracarboxylic acids (particularly this acid dianhydride), and One or more aromatic tetracarboxylic acids selected from the group consisting of bis (3,4-carboxyphenyl) ethers (particularly, this dianhydride) and (ii) 2-phenyl-4,4'-diamino. Aromatic diamines containing diphenyl ether and (iii) 4- (2-phenylethynyl) anhydrous phthalic acid are prepared so that the total amount of dicarboxylic acid groups and the total amount of primary amino groups are approximately equal. ..
2. 2. Each of the prepared monomers is polymerized in an organic solvent at a reaction temperature of about 100 ° C. or lower (preferably about 80 ° C. or lower) to synthesize an amic acid oligomer (A) in a solution state.
3. 3. The solution of the amic acid oligomer is melt-processed at a temperature of 180 ° C. or lower. In this way, amorphous particles containing an amic acid oligomer (P) having a 4- (2-phenylethynyl) phthalic anhydride residue at the terminal are obtained.

Specific examples of a more preferable method for producing amorphous particles containing the amic acid oligomer include the following methods.
Aromatic diamines containing 1.2-phenyl-4,4'-diaminodiphenyl ether are uniformly dissolved in an organic solvent.
2. 2. Aromatic tetracarboxylic dianhydride is added to the obtained solution and dissolved uniformly. The aromatic tetracarboxylic acid dianhydrides are 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 1,2,4,5-benzenetetracarboxylic acid dianhydride, and bis (3,3). 4-Carboxyphenyl) One or more selected from ether dianhydride.
3. 3. The obtained solution is reacted at a reaction temperature of about 5 to 60 ° C. with stirring for about 1 to 180 minutes.
4. 4- (2-Phenylethynyl) phthalic anhydride is added to the obtained reaction solution to uniformly dissolve it.
5. The obtained solution is reacted at a reaction temperature of about 5 to 60 ° C. with stirring for about 1 to 180 minutes. In this way, the amic acid oligomer (A) in the form of a solution is synthesized.
6. The obtained reaction solution is melt-extruded at a temperature of 180 ° C. or lower to cause an imidization reaction and to form particles. After melt extrusion, the obtained particles are cooled to around room temperature, if necessary. As a result, amorphous particles containing the amic acid oligomer (P) having an imide group are synthesized.

It is preferable that all or part of the steps in the above synthesis are carried out under an inert gas atmosphere (atmosphere such as nitrogen gas or argon gas) or under reduced pressure.

Examples of the organic solvent used in the above synthesis include N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methylcaprolactam, and γ-butyrolactone (GBL). , Cyclohexanone, and a mixed solvent of methanol and 1,3-dioxolane. Only one kind of these organic solvents may be used, or two or more kinds may be used in combination. These organic solvents can be appropriately selected by applying known techniques relating to soluble polyimide. Among these, it is more preferable to use a mixed solvent of methanol and 1,3-dioxolane.

That is, in the method for producing an amorphous particle containing an amic acid oligomer (P) having an imide group in one embodiment of the present invention, a solution of the amic acid oligomer (A) represented by the following general formula (2) is used. It is a method including a step of melt processing.

(In formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ are divalent which may be the same or different from each other. Represents the aromatic tetracarboxylic acid residue of, R ₅ and R ₆ are hydrogen atoms or phenyl groups, one of which is a phenyl group, and m and n are 1 ≦ m, 0 ≦ n, 1 The relationship of ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of the repeating unit may be block or random.)
As described above, the solution of the amic acid oligomer can be produced by reacting an aromatic tetracarboxylic acid, an aromatic diamine, and an unsaturated acid anhydride for terminal modification in a solvent. A known production method can be adopted as the method for producing the solution of the amic acid oligomer, and the method is not particularly limited to the above-mentioned method.

As the solvent used for preparing the solution of the amic acid oligomer, that is, the solvent for dissolving the amid acid oligomer, the solvent used at the time of the reaction is suitable, and specifically, for example, N-methyl-2-pyrrolidone (NMP). , N, N-dimethylacetamide (DMAc, boiling point 165 ° C.), N, N-diethylacetamide (boiling point 185 ° C.), boiling point 202 ° C. (hereinafter, the boiling point indicates the temperature under normal pressure unless otherwise specified). , N-Methylcaprolactum (boiling point 120 ° C. under reduced pressure (25 mmHg)) and other amide solvents; γ-butyrolactone (GBL, boiling point 204 ° C.) and other ester solvents; cyclohexanone (boiling point 156 ° C.) and other ketone solvents. 1,3-dioxane (boiling point 105 ° C.), 1,4-dioxane (boiling point 101 ° C.), tetrahydrofuran (boiling point 66 ° C.), 1,3-dioxolane (boiling point 75 ° C.), 1,2-dimethoxyethane (boiling point 83 ° C.) Ether-based solvent such as (° C.); alcohol-based solvent such as methanol (boiling point 65 ° C.), ethanol (boiling point 78 ° C.), 1-propanol (boiling point 98 ° C.), 2-propanol (boiling point 82 ° C.); methoxymethanol (boiling point 90 ° C.) Hydroxyl ethers such as ~ 95 ° C.), ethoxymethanol (boiling point 102 ° C.), 2-methoxyethanol (boiling point 124 ° C.), 2-ethoxyethanol (boiling point 135 ° C.), 1-methoxy-2-propanol (boiling point 119 ° C.) Solvent; Only one kind of these solvents may be used, or two or more kinds may be used in combination. Further, as the solvent, a mixed solvent such as a mixed solvent of methanol and 1,3-dioxolane may be used.

The boiling point (under normal pressure) of the solvent is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, still more preferably 130 ° C. or lower, and 100. Most preferably, it is below ° C. If the boiling point (under normal pressure) exceeds 200 ° C., the precipitation of the amic acid oligomer may not proceed smoothly, or it may be difficult to volatilize the solvent.

Further, from the viewpoint of easiness of precipitation of the imide oligomer at the time of volatilization, the solvent is more preferably an ester solvent, a ketone solvent, an ether solvent, an alcohol solvent, a hydroxy ether solvent, and a mixed solvent of these solvents. , Ether solvent, alcohol solvent, and hydroxy ether solvent, and a mixed solvent of these solvents are more preferable, and an ether solvent and a hydroxy ether solvent, and a mixed solvent of these solvents and an alcohol solvent are particularly preferable. preferable. It is more preferable that the ether solvent has two or more oxygen atoms per molecule because of its excellent solubility. A solvent having too high an ability to dissolve the amic acid oligomer may not allow the precipitation of the amic acid oligomer to proceed smoothly or may make it difficult to volatilize the solvent. In addition, a solvent having too low an ability to dissolve the amide acid oligomer cannot obtain an amide acid oligomer solution having an appropriate concentration.

Among the above-exemplified solvents, an alcohol-based solvent having excellent solubility of tetracarboxylic acids and aromatic diamines used as a raw material for the amic acid oligomer, and an ether-based solvent having excellent solubility of the tetracarboxylic acids and the obtained amic acid oligomer. A single solvent of a hydroxy ether solvent having the characteristics of an alcohol solvent and an ether solvent; a mixed solvent of an alcohol solvent and a hydroxy ether solvent; a mixed solvent of an ether solvent and a hydroxy ether solvent; Alternatively, a mixed solvent of an alcohol solvent, an ether solvent and a hydroxy ether solvent; is particularly preferable because the amic acid oligomer can be efficiently polymerized. Further, in consideration of solubility, it is more preferable that the ether solvent has two or more oxygen atoms per molecule. Further, these solvents have a boiling point (boiling point of each single solvent in the mixed solvent) of 130 ° C. or lower regardless of whether they are used as a single solvent or a mixed solvent. preferable. In consideration of volatility, a mixed solvent of an alcohol-based solvent and an ether-based solvent is more preferable because it forms an azeotropic mixture and volatilizes. Alcohol-based solvents and hydroxyether-based solvents obtain amic acid oligomers because the hydroxyl groups of the molecules stabilize radicals that may be formed from the ether-based solvents during autoxidation by oxygen, for example. There is an advantage that sometimes it becomes difficult to generate peroxide. That is, the alcohol solvent and the hydroxy ether solvent also have a function as a stabilizer for the ether solvent. Unlike the ether solvent, the hydroxy ether solvent has a function of stabilizing itself even when used as a single solvent. However, in anticipation of further stabilization, it may be used as a mixed solvent with an alcohol solvent.

As the mixed solvent of the alcohol-based solvent and the ether-based solvent, specifically, for example, a mixed solvent of methanol and 1,3-dioxolane is suitable, and methanol: 1,3-dioxolane has a weight ratio of 1: 1. A mixed solvent of 4 to 4: 1 is more preferable, and a mixed solvent of 1: 2 to 2: 1 is even more preferable.

The concentration of the solution of the amic acid oligomer is preferably 10 to 90% by weight, more preferably 20 to 70% by weight, still more preferably 30 to 50% by weight. When the concentration of the solution of the amic acid oligomer is within the above range, the particles containing the amid acid oligomer can be efficiently produced.

In the process of melt processing, the amic acid oligomer is melt-processed while volatilizing the solvent from the solution of the amid acid oligomer (A) to prepare an amid acid oligomer (P) having an imide group.
The melting process is preferably performed at a temperature of 180 ° C. or lower. Therefore, the set temperature of the processing machine in the melting process is preferably 80 to 230 ° C, more preferably 100 to 210 ° C, and even more preferably 120 to 190 ° C. If the set temperature of the processing machine is less than 80 ° C., the volatilization of the solvent tends to be insufficient. When the set temperature of the processing machine exceeds 230 ° C., the corresponding imide oligomer tends to be excessively formed or an undesired curing reaction tends to be promoted. The imidization reaction can be easily controlled by adjusting the temperature at the time of melt processing.

The method of melt processing is not particularly limited, but a method of melt extrusion using an extruder as a processing machine is convenient. The extruder that can be used in the process of melt processing may be an extruder that can extrude while melting and kneading the amic acid oligomer by heating, and examples thereof include a single-screw extruder and a twin-screw extruder. However, it is not particularly limited. Of these, a twin-screw screw extruder is preferable. The extruder may be provided with a perforated plate at its tip.

It is desirable that the extruder is provided with a temperature gradient from the supply port side to the extrusion port side so that melt extrusion can be preferably performed. Specifically, the temperature on the supply port side is preferably room temperature to 80 ° C., more preferably room temperature to 50 ° C., and even more preferably near room temperature. The temperature on the extrusion port side is preferably 80 to 230 ° C, more preferably 100 to 210 ° C, and even more preferably 120 to 190 ° C.

The extruder is a desolving device that volatilizes the solvent from the solution of the amidic acid oligomer, a reactor that performs an imidization reaction (dehydration reaction) until the desired imidization rate is reached, and the obtained amidic acid oligomer. It acts as a powdering device for atomizing. Therefore, in the extruder, volatilization (desolventization) of the solvent, imidization reaction when necessary, and powdering can be continuously carried out from the supply port side to the extrusion port side.

That is, in the method for producing particles containing an amic acid oligomer in one embodiment of the present invention, for example, using an extruder, the solution of the amic acid oligomer is melt-kneaded while being heated, and the solvent and the necessary are added during the melt-kneading. In such a case, since the imidization reaction is carried out while volatilizing the water produced by the imidization reaction, it is not necessary to add an imidizing agent and a dehydrating agent even when partial imidization is required. ..

The residence time of the amic acid oligomer in the extruder is preferably 1 to 30 minutes, more preferably 2 to 20 minutes, still more preferably 3 to 10 minutes. By controlling the shape and rotation speed of the extruded member such as a screw to adjust the residence time, the imidization reaction when necessary can be easily controlled. If the residence time is less than 1 minute, the removal of the solvent is insufficient or the desired imidization rate tends not to be obtained. When the residence time exceeds 30 minutes, the curing reaction tends to be promoted.

That is, in the method for producing particles containing an amic acid oligomer according to the embodiment of the present invention, melt extrusion is performed by appropriately adjusting the shape and rotation speed of the extrusion member, the temperature during melt extrusion, and the residence time. The imidization ratio of the amidic acid oligomer-containing particles thus obtained can be easily controlled, if necessary.

The amorphous particles containing the amic acid oligomer (P) having an imide group extruded from the extruder are amorphous particles. When the particles containing the amic acid oligomer are connected to form flakes, they may be lightly pulverized. The obtained amorphous particles containing an amic acid oligomer having an imide group can be subjected to a curing reaction without purification.

In the production method according to the embodiment of the present invention, atypical particles containing an amic acid oligomer (P) having an imide group are produced by performing a solution processing step, and at the time of imidization when necessary. Since no solvent / imidizing agent and dehydrating agent are used in the solution, there is no need for a recovery step of precipitating (precipitating) the amic acid oligomer in the solution with a poor solvent, and a post-step such as a washing step and a drying step. Therefore, the production method according to the embodiment of the present invention can produce particles containing an amic acid oligomer in an extremely short time (several minutes) at a low cost and easily as compared with the prior art.

The particles containing the amic acid oligomer (P) having an imide group obtained by the production method in one embodiment of the present invention are amorphous particles, and each particle has an acute-angled portion (not spherical). .. Whether or not a particle is an "atypical particle" can be easily determined, for example, by observing it with an optical microscope. For example, FIG. 1 in which an amorphous particle containing an amide acid oligomer (P) having an imide group in one embodiment of the present invention produced by the above production method was observed with an optical microscope, and an amide produced by a conventional production method. Comparing the particles containing the acid oligomer with FIG. 2 observed with an optical microscope, the amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention have sharp angles to individual particles. It is easy to understand that it is an "atypical particle".

[8. Prepreg]
The amorphous particles containing the amic acid oligomer (P) having an imide group in one embodiment of the present invention can be mixed with reinforcing fibers to form a prepreg. By using the amorphous particles containing the amic acid oligomer (P) having an imide group in the prepreg according to the embodiment of the present invention, the residual volatile components such as the solvent are reduced. Further, the resin composite material (for example, carbon fiber reinforced composite material) produced by using the above prepreg reduces (or eliminates) defects such as voids caused by volatilization and decomposition of volatile components such as a solvent. It has an extremely advantageous effect of having a glass transition temperature (Tg) equal to or higher than that of the resin alone. In addition, one embodiment of the present invention may include a fiber-reinforced laminated board obtained by laminating the above prepreg and heat-curing it.

The residual volatile content of the prepreg is preferably 20% by weight or less, more preferably 10% by weight or less, based on the weight derived from the amid acid oligomer (P) having an imide group contained in the prepreg. It is more preferably 8% by weight or less. The volatile content of the prepreg also includes an organic solvent at the time of producing the amidic acid oligomer and a water content desorbed at the time of imidization of the amidic acid oligomer. If the residual volatile content of the prepreg is within the above range, defects such as voids due to volatilization and decomposition of the solvent and the like occur when a resin composite material (for example, a carbon fiber reinforced composite material) is produced using the prepreg. It is preferable because a good composite material having a Tg equal to or higher than that of the resin alone can be obtained by reducing or eliminating the resin.

Further, in one embodiment of the present invention, the prepreg and the resin composite material are produced without preparing a suspension of particles containing the amic acid oligomer even if the amic acid oligomer has a relatively large molecular weight. be able to. Further, the prepreg can maintain the drape property, and the obtained resin composite material has excellent heat resistance.

In addition, in this specification, "prepreg" means a resin-reinforcing fiber composite in which atypical particles containing an amic acid oligomer are partially impregnated into the reinforcing fiber (semi-impregnated state) and integrated. The "prepreg" contains a fiber arrangement that is not impregnated with the resin because it is in a semi-impregnated state, whereby the drape property is not impaired, and the formability to a complicated shape is good. As one aspect of the "prepreg", it often shows a form in which a resin-rich layer is provided on the outer surface of the reinforcing fiber.

The above-mentioned "drape property" means an index indicating the degree of suppleness of deformation of the resin-reinforced fiber composite. "Drapeability" is an index showing the degree to which a resin-reinforcing fiber complex flexibly follows its shape without breaking or breaking of the reinforcing fiber when it is deformed along other objects such as a mold. be. If the drape property is high, it is easy to shape the curved surface, and if the drape property is low, it is difficult to shape the curved surface. Further, if the drape property is low, it is naturally difficult to form a press-molded product having a complicated shape.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the present invention can be obtained by appropriately combining the technical means disclosed in the different embodiments. Embodiments are also included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The pressures in the examples and the comparative examples are all the actual pressures applied to the sample, not the display pressure (gauge pressure) of the press machine or the like.

[Various test methods for particles containing imide oligomers]
(1) Measurement of glass transition temperature (Tg) and heat generation start temperature Measurement was performed using a Q100 (DSC) device manufactured by TA Instruments. The measurement conditions were 1st run: 40 to 450 ° C., heating rate 20 ° C./min, 2nd run: 40 to 500 ° C., and heating rate 20 ° C./min. Then, the intersection of the two tangents before and after the decrease of the heat flow (W / g) curve of the 2nd run was defined as the glass transition temperature (Tg) after the particles containing the imide oligomer were cured. That is, the glass transition temperature (Tg) of the particles (powder) containing the imide oligomer after curing is Tg of 2nd run in the DSC measurement. When an exothermic peak was observed on the heat flow (W / g) curve, the temperature of the exothermic peak was defined as the curing exothermic peak temperature of the particles containing the imide oligomer.

(2) Measurement of imidization rate Proton nuclear magnetic resonance spectroscopy (model: AV-400M, Bruker Co., Ltd.) was prepared by dissolving the imide oligomer in heavy DMF (dihydroformamide N, N-dimethylformamide) and using it as a measurement sample. The peak area was measured at 30 ° C. using ¹ H-NMR). Then, from the peak area derived from aromatic 1H having ^a chemical shift of 7 to 9 ppm and the peak area derived from residual amide 1H having ^a chemical shift of around 11 ppm, the imidization rate (mol%) of the particles containing the imide oligomer was determined. Was calculated.

(3) Measurement of particle size distribution and average particle size Particles containing an imide oligomer are dispersed in water to prepare a measurement sample, and an imide is used using a laser diffraction type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd .: Microtrac). The volume average particle size distribution of the particles containing the oligomer was measured. Then, the 50% cumulative volume average particle diameter was defined as the average particle diameter (μm) of the particles containing the imide oligomer.

(4) Tensile test Using Autograph AGS-X manufactured by Shimadzu Corporation, a cured film (press molding) made from particles containing an imide oligomer at a chuck distance of 20 mm and TS: 5 mm / min. The product) was subjected to a tensile test, and mechanical properties (tensile elastic modulus (N / mm ² ), fracture stress (N / mm ² ), and fracture strain (%)) were measured.

(5) Solubility test To 0.1 g of particles containing an imide oligomer, 10 g of N-methyl-2-pyrrolidone (NMP) was added, and the mixture was stirred at room temperature for 1 hour so that the concentration became 1% by weight, and then visually observed. A solubility test was conducted by confirming the presence or absence of insoluble matter.

(6) Particle shape An appropriate amount of particles containing the imide oligomer was taken, and the shape of the aggregated particles was observed using an optical microscope (VHX-5000, manufactured by KEYENCE). Further, 3.7 g of methanol was placed in a screw tube, particles containing about 0.1 mg of imide oligomer were added, and then ultrasonic waves were applied for 10 minutes using an ultrasonic cleaning device. The resulting suspension was then collected with a Pastur pipette, dropped onto a glass plate, dropped and dried thoroughly at room temperature during the draft. Then, the shape of each particle was observed by using an ultra-deep microscope (manufactured by KEYENCE) as a residue after volatilizing methanol.

(7) Fluidity The evaluation of the fluidity of the particles containing the imide oligomer is good (A), slightly good (B), normal (C), and usable (it can be used at the last minute) (D). ), Defect (E).

(8) Residual solvent rate Approximately 2 mg of particles containing the amidic acid oligomer were weighed and heated by TGA-50 (manufactured by Shimadzu Corporation) from room temperature to 600 ° C. at 5 ° C./min under a nitrogen stream. The weight loss rate observed near the glass transition temperature (Tg) was defined as the solvent content (residual solvent rate).

(9) BET specific surface area Particles containing an amidic acid oligomer were put into TriStar3000 (manufactured by Shimadzu Corporation), pretreated in air at 120 ° C. for 1 hour, and then subjected to pretreatment in air at 120 ° C. and then BET specific surface area at 77K with nitrogen. Was measured.

(10) GPC molecular weight Prepare an N-methylpyrrolidone (containing 0.01 M LiBr) solution of particles containing an amid acid oligomer, and use 20 μL of the sample in a deaerator, pump, column oven, UV detector, and so on. The measurement was carried out by Prominence (manufactured by Shimadzu Corporation) equipped with a refractive index detector and connected in series with Phenogen (column, manufactured by Phenomenex). The calibration curve preparation sample was standard polystyrene (manufactured by TOSOH).

[Manufacturing Example 1]
After heating the inside of a 7L autoclave equipped with a thermometer and a stir bar to 45 ° C. with a heater, 1105 g (4.0 mol) of 2-phenyl-4,4'-diaminodiphenyl ether (Ph-ODA), and 1, A mixed solvent of 1650 g of 3-dioxolane and 1650 g of methanol (weight ratio 1: 1) was added, and the nitrogen flow was started. After dissolving 2-phenyl-4,4'-diaminodiphenyl ether, 232.6 g of 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) was added to the above autoclave three times at intervals (697 in total). 8.8 g (3.2 mol)) was added, and the polymerization reaction was carried out at a set temperature of 45 ° C. for 3 hours to obtain an amic acid oligomer. To the reaction solution containing this amic acid oligomer, 397.1 g (1.6 mol) of 4- (2-phenylethynyl) phthalic anhydride (PEPA) was added, and the reaction was continued for 1.5 hours for terminal denaturation. As a result, a solution of the terminal-modified amic acid oligomer was obtained (solid content concentration (theoretical value) = 2200/5500 = about 40% by weight).

The obtained terminally modified amic acid oligomer has n = 0 in the above general formula (2), R ₁ is represented by a 2-phenyl-4,4'-diaminodiphenyl ether residue, and R ₃ is 1,2. , 4,5-benzenetetracarboxylic acid dianhydride residue, on average m = 4 (tetramer). The obtained solution of the terminal-modified amic acid oligomer was referred to as varnish (N1). The imidization rate of the terminal-modified amidic acid oligomer in the varnish was almost 0%.

[Manufacturing Example 2]
23.43 g (84.8 mmol) of 2-phenyl-4,4'-diaminodiphenyl ether and 82.5 g of N-methyl-2-pyrrolidone (NMP) in a three-necked 300 mL flask equipped with a thermometer and a stir bar. And put in. After dissolving 2-phenyl-4,4'-diaminodiphenyl ether, 3.28 g (9.41 mmol) of 9,9-bis (4-aminophenyl) fluorene was added to the flask, and the mixture was stirred until it was dissolved. Subsequently, 16.44 g (75.4 mmol) of 1,2,4,5-benzenetetracarboxylic acid dianhydride was added to the flask, the mixture was sealed with nitrogen, and the polymerization reaction was carried out at room temperature for 1.5 hours. Obtained an amic acid oligomer. To the reaction solution containing this amic acid oligomer, 9.35 g (37.7 mmol) of 4- (2-phenylethynyl) phthalic anhydride and 15 g of NMP are added, filled with nitrogen, and reacted at room temperature for 1.5 hours. End denatured by. Further, a nitrogen introduction tube was attached to the flask, and the mixture was stirred at 200 ° C. for 5 hours under a nitrogen stream to form an imide bond, and then cooled to obtain an NMP solution of the terminally modified imide oligomer (solid content concentration (theory). Value) = 52.5 / 150 = about 35% by weight).

In the obtained terminally modified imide oligomer, _R1 is represented by a 2-phenyl-4,4'-diaminodiphenyl ether residue or a 9,9-bis (4-aminophenyl) fluorene residue in the above general formula (1). R ₂ is represented by 9,9-bis (4-aminophenyl) fluorene residues, and R ₃ and R ₄ are represented by 1,2,4,5-benzenetetracarboxylic acid dianhydride residues. On average, m = 3.6 and n = 0.4. The obtained NMP solution of the terminal-modified imide oligomer was referred to as varnish (N2). The imidization rate of the terminal-modified amidic acid oligomer in the varnish was almost 0%.

[Example 1]
As a twin-screw extruder used in the melting process, MPU25TW (manufactured by Technobel Co., Ltd.), which is a twin-screw extruder in the same direction, has a screw diameter of 25 mmφ, and has a maximum effective screw length (L / D) of 60, was used. The heater temperature of the cylinder of this twin-screw extruder is set to water cooling only for the varnish inlet (C0), 40 ° C for the inlet side block (C1), 80 ° C for the upstream intermediate block (C4), and downstream. Approximately half of the blocks (C6 to C10, DH) on the side were set to 150 ° C., and a temperature gradient was set between them. The die head was opened without attaching a die to the downstream end of the twin-screw extruder. The screw rotation speed was set to 10 rpm. This rotation speed corresponds to a residence time: about 6 minutes.

When the varnish (N1) was charged from the varnish charging port (C0), yellow powder was discharged from the downstream end of the twin-screw extruder. No blocking was observed in the obtained powder, and it had a usable fluidity. No insoluble matter was confirmed in the solubility test. When this powder was measured by the various test methods described above, the imidization rate was 7.1 mol%, the average particle size was 55 μm (single peak), and the particle shape was amorphous. Therefore, the powder was amorphous particles containing an amic acid oligomer.

Further, this powder was put into a hot press heated to 325 ° C. to preheat it, and after confirming that it had melted, the powder was gradually pressurized and the air bleeding operation was repeated by pumping. After that, the cured product film (press molded product) obtained by heating and pressurizing for 1 hour after reaching 370 ° C. by heating while applying a predetermined pressure is subjected to a tensile test to obtain mechanical properties (tensile elastic modulus). When the rate, breaking stress, and breaking strain) were measured, good physical properties were shown. The results are summarized in Table 1.

[Example 2]
As for the heater temperature of the cylinder of the twin-screw extruder, the varnish inlet (C0) is only water-cooled, the inlet side block (C1) is 40 ° C, the upstream intermediate block (C4) is 80 ° C, and the downstream side. About half of the blocks (C6 to C10, DH) were set to 150 ° C., and a temperature gradient was set between them. The screw rotation speed was set to 30 rpm. This rotation speed corresponds to a residence time: about 3 minutes. Other than that, the varnish (N1) was charged from the varnish charging port (C0) under the same conditions as in Example 1.

When the varnish (N1) was charged from the varnish charging port (C0), yellow powder was discharged from the downstream end of the twin-screw extruder. No blocking was observed in the obtained powder, and it had a usable fluidity. No insoluble matter was confirmed in the solubility test. When this powder was measured by the various test methods described above, the imidization rate was 20.0 mol%, the average particle size was 48 μm (single peak), and the particle shape was amorphous. Therefore, the powder was amorphous particles containing an amic acid oligomer.

Further, when the mechanical physical characteristics of the cured film obtained from this powder under the same conditions as in Example 1 were measured by conducting a tensile test, good physical characteristics were shown. The results are summarized in Table 1.

[Comparative Example 1]
As for the heater temperature of the cylinder of the twin-screw extruder, the varnish inlet (C0) is only water-cooled, the inlet side block (C1) is 40 ° C, the upstream intermediate block (C4) is 80 ° C, and the downstream side. About half of the blocks (C6 to C10, DH) were set to 200 ° C., and a temperature gradient was set between them. The screw rotation speed was set to 30 rpm. This rotation speed corresponds to a residence time: about 3 minutes. Other than that, the varnish (N1) was charged from the varnish charging port (C0) under the same conditions as in Example 1.

When the varnish (N1) was charged from the varnish charging port (C0), yellow powder was discharged from the downstream end of the twin-screw extruder. No blocking was observed in the obtained powder, and it had normal fluidity. No insoluble matter was confirmed in the solubility test. When this powder was measured by the various test methods described above, the imidization rate was 91.8 mol%, the average particle size was 54 μm (single peak with a shoulder), and the particle shape was amorphous. Therefore, the powder was not an amorphous particle containing the amic acid oligomer of the present invention. The results are summarized in Table 1.

[Comparative Example 2]
Without using a twin-screw extruder, varnish (N1) was poured into a glass container and allowed to stand in a vacuum oven set at 45 ° C for 18 hours, and then left in a hot air oven set at 250 ° C for 1 hour. And obtained a yellow solid. That is, no powder was obtained.

When this solid was cut out and measured by the various test methods described above, the imidization rate was 99.9%. No insoluble matter was confirmed in the solubility test. Further, the mechanical properties of the cured film obtained from this solid under the same conditions as in Example 1 were measured by a tensile test. The results are summarized in Table 1.

[Comparative Example 3]
100 g of varnish (N2) was put into 720 g of methanol, and the precipitated powder was filtered off. The obtained powder was washed with 480 g of methanol for 30 minutes repeatedly 5 times, and then the powder was separated by filtration. The obtained powder was dried under reduced pressure at 120 ° C. for 1 day to obtain granular terminal-modified imide oligomers. Further, the obtained granular terminal-modified imide oligomer was pulverized with a hammer mill to obtain a terminal-modified imide oligomer powder.

No blocking was observed in the obtained powder, and it had a usable fluidity. No insoluble matter was confirmed in the solubility test. When this powder was measured by the various test methods described above, the imidization rate was 98.2 mol%, the average particle size was 71 μm (single peak), and the particle shape was amorphous. Further, the mechanical properties of the cured film obtained from this powder under the same conditions as in Example 1 were measured by a tensile test and found to be good. The results are summarized in Table 1.

[Consideration for results]
Comparing Examples 1 and 2, the powder obtained by setting the heater temperature of the extruder (referring to the set temperature of approximately half the blocks (C7 to C10) on the downstream side; the same applies hereinafter) to 150 ° C. It can be seen that the imidization rate of (atypical particles containing an amic acid oligomer) can be made to be approximately 20 mol% or less, and the fluidity of the powder is not impossible. Further, it can be seen that the imidization rate can be controlled by controlling the screw rotation speed even if the heater temperature of the extruder is the same.

Among them, it can be seen that in the physical properties of the cured product shown in Example 2, the value of the breaking strain is particularly large and the mechanical properties are excellent. Although the reason is unknown, the imide oligomer, which is a partially imidized component, forms a domain because it is difficult to melt, and the amic acid oligomer forms a matrix because it is easy to melt, and it is possible to make the crosslinks coarse and dense. It is presumed that the structure is flexible and tenacious, and the elongation at break is improved without significantly deteriorating the elastic coefficient. That is, from the viewpoint of mechanical characteristics, it is presumed that the imidization rate has an optimum point.

Further, comparing Examples 1 and 2 with Comparative Example 1, by raising the heater temperature of the above-mentioned extruder to 200 ° C., the imidization rate is remarkably improved so as to exceed the upper limit of 80% in the present invention. , It can be seen that particles containing an amic acid oligomer cannot be obtained.

Comparing the physical characteristics of the cured product film produced from the amorphous particles containing the amic acid oligomer obtained in Examples 1 and 2 with the physical characteristics of the cured product film produced from the varnish obtained in Comparative Example 2. It can be seen that Example 1 and Comparative Example 2 show similar physical properties. However, in Comparative Example 2, it takes 19 hours or more to obtain a solid from the varnish (N1), which is inferior in efficiency. Moreover, in Comparative Example 2, it takes time and effort to cut out the obtained solid and then process it into a cured film, which is inferior in processability and handleability. On the other hand, it can be seen that Examples 1 and 2 are excellent in efficiency, processability and handleability.

In Comparative Example 3, a terminal-modified imide oligomer powder is obtained by a conventional production method (pulverization method). Comparing the physical characteristics of the cured product film obtained in Examples 1 and 2 with the physical characteristics of the cured product film obtained in Comparative Example 3, it can be seen that Comparative Example 3 exhibits smaller elongation and harder physical properties. Further, in Comparative Example 3, it takes a long time together with a large amount of methanol to reprecipitate from the varnish (N2) to obtain a powder, which is inferior in efficiency. Moreover, in Comparative Example 3, it takes time and effort to crush the powder with a hammer mill (crusher) to obtain the powder, and the processability and handleability are also inferior. On the other hand, it can be seen that Examples 1 and 2 are excellent in efficiency, processability and handleability.

Since the present invention has excellent moldability, heat resistance, mechanical properties, electrical properties, and the like, the present invention is used for aircraft, space industry equipment, electrical and electronic equipment, general industrial use, and vehicle engines. It can be used as a material (heat-resistant composite material) in a wide range of fields such as peripheral) members.

Claims (8)

Amid acid having an imide group in which a part of the amid acid unit in the amid acid oligomer (A) represented by the following general formula (2) is converted into an imide ring and the imidization rate is 1% to 80%. Atypical particles containing an oligomer (P) and having an average particle diameter in the range of 100 to 500 μm measured by dispersing in water.

(In general formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ may be the same or different from each other. Representing a good tetravalent aromatic tetracarboxylic acid residue, R ₅ and R ₆ are one of which is a hydrogen atom and the other of which is a phenyl group, where m and n are 1 ≦ m, 0 ≦ n, The relationship of 1 ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of repeating units may be block or random.) The amorphous particle according to claim 1, which contains 20% by weight or less of a solvent. The solvent is a mixed solvent of an alcohol-based solvent and an ether-based solvent, a single solvent of a hydroxy-ether-based solvent, a mixed solvent of an alcohol-based solvent and a hydroxy-ether-based solvent, a mixed solvent of an ether-based solvent and a hydroxy-ether-based solvent, or a mixed solvent. The amorphous particle according to claim 2, which is a mixed solvent of an alcohol solvent, an ether solvent and a hydroxy ether solvent, and the boiling point thereof (the boiling point of each single solvent in the mixed solvent) is 130 ° C. or lower. .. The amorphous particle according to claim 3, wherein the solvent is a mixed solvent of methanol and 1,3-dioxolane. An imide group-containing amid acid oligomer (a imide group-containing amid acid oligomer in which a part of the amid acid unit in the amid acid oligomer (A) represented by the following general formula (2) is converted into an imide ring and the imidization ratio is 0 to 1%. The method for producing an amorphous particle according to claim 1, which comprises a step of melting the solution of P).

(In general formula (2), R ₁ and R ₂ represent divalent aromatic diamine residues that may be the same or different from each other, and R ₃ and R ₄ may be the same or different from each other. Representing a good tetravalent aromatic tetracarboxylic acid residue, R ₅ and R ₆ are one of which is a hydrogen atom and the other of which is a phenyl group, where m and n are 1 ≦ m, 0 ≦ n, The relationship of 1 ≦ m + n ≦ 20 and 0.05 ≦ m / (m + n) ≦ 1 is satisfied, and the sequence of repeating units may be block or random.) The method for producing amorphous particles according to claim 5, wherein the melting process is performed at a temperature of 250 ° C. or lower. The method for producing amorphous particles according to claim 6, wherein an extruder is used during melt processing. The method for producing amorphous particles according to claim 7, wherein the residence time in the extruder is 1 to 30 minutes.

Images