JPH0649242A - Production of laminated molded article - Google Patents

Abstract

PURPOSE:To obtain a laminated molded article excellent in heat resistance without damaging characteristics of polyimide by using a new prepreg sheet having excellent strength at high temperature prepared from a specific polyamic acid and a fibrous reinforcing material by a specific method. CONSTITUTION:First, a solution of a polyamic acid having a unit of formula I (R1 is bifunctional group selected from >=2C aliphatic group, monocyclic aromatic group, etc.; R2 is tetrafunctional group selected from >=2C aliphatic group, heterocyclic group, etc.; Y is H, alkyl, etc.) in an organic solvent is reacted with a dehydrated imidating agent (e.g. acetic anhydride) and the polyamic acid is chemically imidated to give a polyimide resin having a unit of formula II. Then the powder of the resin preferably in a suspended state in a solvent is applied to a fibrous reinforcing material, heated to >= the glass transition temperature of the polyimide and melted to give a prepreg sheet impregnated with the polyimide resin. Successively the prepreg sheet is laminated and heated to >= the glass transition temperature of the polyimide under heating to give the objective product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminated molded product from a prepreg sheet obtained by a method for producing a prepreg sheet useful as a heat-resistant adhesive, a heat-resistant composite material and the like.

[0002]

2. Description of the Related Art In the fields of electronics, aerospace equipment, transportation equipment, etc., various industrial materials are required to have high temperature characteristics in order to achieve high performance and light weight. Conventionally, epoxy-based, modified epoxy-based, phenolic-based resins, etc., which have been used as structural adhesives or prepregs for laminated molded bodies, have a remarkable drawback in heat resistance. Epoxy resins and the like have a problem in storage stability and have a drawback that they need to be stored at a low temperature. A polyimide resin is used as a material for improving such a defect. However, when a normal polyimide resin is completely cyclized to be in a polyimide state, its melt fluidity becomes very poor, which makes it difficult to use. On the other hand, although the melt fluidity improves in the state where the solvent or the polyamic acid remains, voids are generated in the molded product or the adhesive layer due to the water generated during the cyclization of the residual solvent or the amic acid group during processing, It is not preferable because it lowers the physical properties. As a polyimide resin having improved melt fluidity, tetracarboxylic dianhydride such as 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride and diamine such as 3,3′-diaminobenzophenone are used in an organic solvent. A polyimide resin obtained by heating and imidizing a polyamic acid obtained by the reaction was developed by the National Aeronautics and Space Administration (NASA). (For example, U.S. Pat.
No. 4,094,862. However, the melt fluidity of this polyimide resin is not yet sufficiently satisfactory, and the performance is not sufficient for use in a prepreg.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made from the above point of view, and an object of the present invention is to improve the melt flowability of a polyimide and to form a heat resistant laminate. It is an object of the present invention to provide a method for producing a heat-resistant laminated molded body using materials widely used as a body or an adhesive.

[0004]

The inventors of the present invention have finally made the present invention as a result of extensive studies to achieve the above object. That is, the present invention uses the formula (1)

[Chemical 3] [In the formula, R ₁ represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-bonded group in which aromatic nuclei are interconnected by a bridging member. Represents a divalent group selected from the group consisting of a condensed polycyclic aromatic group and a heterocyclic group,
R ₂ is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-condensed polycyclic group in which aromatic nuclei are interconnected by a bridging member. It represents a tetravalent group selected from the group consisting of aromatic groups and heterocyclic groups, and Y represents a group selected from the group consisting of hydrogen atoms, alkyl groups and aryl groups. ] The organic solvent solution of the polyamic acid having the repeating unit represented by

[Chemical 4] Wherein, R ₁ and R ₂ has the formula (1) is identical to R ₁ and R ₂ in] after coating the polyimide resin powder having a repeating unit represented by the fibrous reinforcing material, of the polyimide Heating and melting above a glass transition point to obtain a prepreg sheet obtained by a method for producing a prepreg sheet characterized by impregnating and heating under a pressure above the glass transition point of the polyimide contained in the prepreg sheet. It is a method for producing a characteristic laminated molded body.

In the present invention, polyamic acid is first synthesized. Polyamic acid can be synthesized by a known method. Generally, it is synthesized by reacting a tetracarboxylic dianhydride and a diamine compound in an organic solvent. Specifically, for example, by dissolving or suspending a diamine compound in an organic solvent and gradually adding tetracarboxylic dianhydride under a stream of dry nitrogen, or vice versa, diamine is added to the tetracarboxylic dianhydride solution. It is synthesized by gradually adding the compound.

The tetracarboxylic dianhydride used is preferably, for example, the following. Pyromellitic anhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3', 4'-benzophenone tetracarboxylic dianhydride, 2,2 ', 3,3' -Benzophenone tetracarboxylic dianhydride, 4,4 ', 5
5 ', 6,6'-hexafluorobenzophenone-2,
2 ', 3,3'-tetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,5,6-trifluoro-3,
4-dicarboxyphenyl) methane dianhydride, 1,1-
Bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride Anhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (2,5,5
6-trifluoro-3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,5,6-trifluoro-3,4-dicarboxy) Phenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) -phenylphosphonate dianhydride, bis (3,4-dicarboxyphenyl) -phenylphosphine oxide dianhydride, N,
N- (3,4-dicarboxyphenyl) -N-methylamine dianhydride, bis (3,4-dicarboxyphenyl)
-Diethylsilane dianhydride, bis (3,4-dicarboxyphenyl) -tetramethyldisiloxane dianhydride,
3,3 ', 4,4'-Tetracarboxybenzoyloxybenzene dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,
7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride,
1,4,5,8-tetrafluoronaphthalene-2,3
6,7-Tetracarboxylic acid dianhydride, 1,8,9,10
-Phenanthrene tetracarboxylic dianhydride, 3,4
9,10-perylenetetracarboxylic dianhydride, 2,
3,4,5-thiophenetetracarboxylic dianhydride,
2,3,5,6-pyrazinetetracarboxylic dianhydride,
2,3,5,6-pyridinetetracarboxylic dianhydride,
Tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride, 3,3 ', 4,4'-azobenzenetetracarboxylic dianhydride, 3,3', 4,4'-azoxybenzenetetracarboxylic Acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, ethylenetetracarboxylic acid dianhydride, butanetetracarboxylic acid dianhydride and the like. Among them, particularly preferable tetracarboxylic acid dianhydride is 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride (hereinafter abbreviated as BTDA). These tetracarboxylic dianhydrides may be used alone or in admixture of two or more.

The following diamine compounds are desirable. o-, m- and p-phenylenediamine, 2,
4-diaminotoluene, 1,4-diamino-2-methoxybenzene, 2,5-diaminoxylene, 1,3-diamino-4-chlorobenzene, 1,4-diamino-2,5
-Dichlorobenzene, 1,4-diamino-2-bromobenzene, 1,3-diamino-4-isopropylbenzene, 2,2-bis (4-aminophenyl) propane,
3,3'- or 4,4'-diaminodiphenylmethane,
3,4'-diaminodiphenylmethane, 2,2'- or 4,4'-diaminostilbene, 4,4'-diamino-
2,2 ', 3,3', 5,5 ', 6,6'-octafluorodiphenylmethane, 3,3'- or 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4' -Diamino-2,2 ', 3
3 ', 5,5', 6,6'-octafluorodiphenyl ether, 3,4'-diaminodiphenylthioether, 3,3'- or 4,4'-diaminodiphenylthioether, 4,4'-diaminodiphenylsulfone,
3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4-aminobenzoic acid 4'-
Aminophenyl ester, 2,2'-, 3,3'- or 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 2,3'-diaminobenzophenone, 4,4'-diaminobenzyl, 4- (4-Aminophenylcarbamoyl) aniline, bis (4-aminophenyl) -phosphine oxide, bis (4-aminophenyl) -methylphosphine oxide, bis (3-aminophenyl) -methylphosphine oxide, bis (4-aminophenyl) ) -Cyclohexylphosphine oxide,
N, N-bis (4-aminophenyl) -N-phenylamine, N, N-bis (4-aminophenyl) -N-methylamine, 2,2 '-, 3,3'- or 4,4' -Diaminoazobenzene, 4,4'-diaminodiphenylurea, 1,8- or 1,5-diaminonaphthalene, 1,5
-Diaminoanthraquinone, diaminofluoranthene,
3,9-diaminochrysene, diaminopyrene, bis (4
-Aminophenyl) -diethylsilane, bis (4-aminophenyl) -dimethylsilane, bis (4-aminophenyl) -tetramethyldisiloxane, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6- Diaminoacridine, 2,4-diamino-S-triazine,
2,7-diamino-dibenzofuran, 2,7-diaminocarbazole, 3,7-diaminophenothiazine, 5,
6-diamino-1,3-dimethyluracil, 2,5-diamino-1,3,4-thiadiazole, dimethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nona Methylenediamine,
Decamethylenediamine, 2,2-dimethylpropylenediamine, 2,5-dimethylhexamethylenediamine,
2,5-dimethylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 3-methoxyhexamethylenediamine,
5-methylnonamethylenediamine, 2,11-diaminododecane, 1,12-diaminooctadecane, 1,2-
Bis (3-aminopropoxy) -ethane and the like. Among them, a particularly preferred diamine compound is 3,3′-diaminobenzophenone (hereinafter abbreviated as 3,3′-DABP). These diamine compounds may be used alone or in 2
Use by mixing more than one species.

Further, N, N'-dialkyl or diaryl-substituted diamine compounds such as N, N'-diethylethylenediamine, N, N'-diethyl-1,3-diamino are used within a range that does not significantly affect the physical properties of the polyimide resin. Propane, N, N'-dimethyl-1,6-diaminohexane, N, N'-diphenyl-1,4-phenylenediamine and the like can be used in combination. The organic solvent used is N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N-acetyl-2-pyrrolidone, sulfolane, dimethyl sulfoxide, diethylene glycol dimethyl ether and the like.
These solvents are used alone or as a mixture. The resulting polyamic acid solution contains the usual 2 to 50% resin content, or the viscosity of the solution is in the range of 10 to 50,000 centivoice as the viscosity measured by Brookfield viscometer. It is preferable in terms of easiness of handling and impregnation into the reinforcing material.

The polyamic acid has an intrinsic viscosity of 0.2 to
It is preferable to be in the range of 2.0 dl / g from the viewpoint of mechanical strength, melt fluidity, heat resistance and the like of the obtained polyimide resin. The intrinsic viscosity is calculated by the following formula. η inh = (1 / C) · ln (η / η _O ) (In the above formula, ln = natural logarithm η = viscosity of a solution of 0.5 g of polyamic acid dissolved in 100 ml of N, N-dimethylacetamide (35 ° C.) η _O = viscosity of N, N-dimethylacetamide (35 ° C.) C = polymer solution concentration expressed in g of polyamic acid per 100 ml of solvent.)

Next, the obtained organic solvent solution of polyamic acid is reacted with a dehydration imidizing agent. As a dehydration imidizing agent, for example, acetic anhydride, propionic anhydride, isobutyric anhydride,
Use one or a mixture of butyric anhydride. The chemical imidization method is generally the following two methods. The first method is a method of adding a dehydration imidizing agent to a polyamic acid solution. In the second method, conversely, a polyamic acid solution is added to the dehydration imidizing agent. Other methods may be used.

For example, when the dehydrating imidizing agent is added to the polyamic acid solution of the first method, it is preferable to add the dehydrating imidizing agent at -10 ° C / 150 ° C. The dehydration imidizing agent may be added directly to the polyamic acid or diluted with an organic solvent and added. The amount of the dehydration imidizing agent added is 0.8-based on the carboxyl groups present in the polyamic acid.
4 equivalents, particularly preferably 1 to 2 equivalents, are used. It is also possible to add an imidization catalyst at the same time, and examples of the catalyst include trimethylamine, triethylamine, tributylamine, pyridine, α-picoline, β-picoline, γ.
And tertiary amines such as picoline and lutidine. When using a catalyst, 0.05 to 1.5 equivalents, preferably 0.2 to the carboxyl groups present in the polyamic acid.
Use ~ 1 equivalent. When the dehydrating imidizing agent is added while stirring the polyamic acid solution, imidization starts, and when the stirring is continued after the addition, the polyimide resin is precipitated in powder form.
This is separated by filtration, thoroughly washed with water and / or an organic solvent, and then dried by heating to obtain a polyimide resin powder.

The second method is a method for producing a polyimide resin powder by adding a polyamic acid solution to a dehydration imidizing agent, and in this case, the same dehydrating imidizing agent and imidization catalyst as those used in the first method are used. To do. Upon addition, it is preferable to add the polyamic acid solution while stirring the dehydration imidizing agent. The dehydration imidizing agent is preferably used in an amount of 1 equivalent or more with respect to the carboxyl group present in the polyamic acid. Further, as in the first method, the dehydration imidizing agent may be diluted with an organic solvent before use. The deposited polyimide resin is treated in the same manner as in the first method to obtain a powder. In the polyimide resin thus obtained, even if an uncyclized amic acid group in a range that does not significantly affect the physical properties remains, or there is a thermally imidized portion that does not depend on chemical imidization. It doesn't matter.

Next, a polyimide resin powder is applied to the fiber reinforcing material, and the fiber reinforcing material is further heat-melted and impregnated. Typical examples of the fibrous reinforcing material include glass fiber, carbon fiber, aromatic polyamide fiber, aromatic polyamide non-woven fabric, and boron fiber. These fibers are used alone or in combination. Further, if necessary, other reinforcing materials such as silicon carbide fiber, mica, calcium silicate, silica and alumina may be used in combination with the above fiber. It is possible to apply the polyimide resin powder directly to the fibrous reinforcing material as the application method,
The method of suspending in a solvent and applying is easy in terms of work. The heating temperature must be at least the glass transition point of the polyimide resin powder and is 240 to 360 ° C.

It is also possible to use, as the fibrous reinforcing material in the present invention, one which is impregnated with polyamic acid in advance, is thermally and / or chemically imidized, and is further volatile removed. In this case, a prepreg sheet in which the polyimide resin is sufficiently impregnated can be manufactured.
The prepreg sheet obtained by the above operation preferably contains 20 to 80% of resin.

The method of applying the polyimide resin of the present invention to the fibrous reinforcing material, heating and melting it to impregnate it is carried out by impregnating a polyamic acid solution which is generally used in the prior art, and then heating to remove the solvent and imidize. It has the following advantages over the method. Since it contains almost no solvent, a large amount of resin can be impregnated at one time, and there is no need to divide the impregnation operation into several times.
Moreover, problems such as foaming due to heating do not occur. Also,
A prepreg sheet containing almost no volatile matter can be produced, and blisters do not occur in the subsequent laminating or bonding operation. Further, the polyimide-impregnated prepreg sheet produced by the chemical imidization operation used in the present invention has excellent melt fluidity of the polyimide resin contained as compared with the prepreg sheet obtained by heating and imidizing polyamic acid, and a material for a laminated molded article. Alternatively, it is suitable as an adhesive. The laminated molded product is obtained by laminating the prepreg sheets obtained as described above and heating and pressing.
The heating temperature during lamination is not less than the glass transition point of the polyimide contained in the prepreg sheet, preferably 240 to 360.
℃. The applied pressure is 1 to 500 depending on the shape.
kg / cm ² is desirable.

[0016]

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples. Example-1 (a) Polymerization N, N-dimethylacetamide was added to a 500 ml four-necked flask.
300ml, 3,3'-DABP 31.85g (0.15mol) was added, and BTDA powder with stirring at 15 ° C under a dry nitrogen stream.
48.33 g (0.15 mol) was added slowly. The viscosity of the solution increases with the addition. After the addition was completed, stirring was continued for a further 4 hours to complete the reaction. The obtained polyamic acid was light brown and transparent and had an intrinsic viscosity of 0.69 dl / g (0.5 g / 100 ml N, N-dimethylacetamide solvent, 35 ° C.). (b) Production of Polyimide Resin Powder Following the total amount of the polyamic acid solution obtained in (a), 45.94 g of acetic anhydride, 8.4 g of β-picoline (0.09 mol), N, N-
A solution consisting of 40 g of dimethylacetamide was added dropwise at 20 ° C under a stream of dry nitrogen while stirring. When the stirring was continued for 6 hours after the dropping, a pale yellow polyimide resin was deposited.
The polyimide resin was separated from the solvent and imidizing agent by filtration, washed with water or methanol, and dried under reduced pressure at 120 ° C. (c) Impregnation The polyimide resin powder obtained in (b) was applied to a glass fiber cloth (WF-230 manufactured by Nitto Boseki Co., Ltd.). Next, it was heated to 295 ° C. to melt and impregnate the resin powder to produce a polyimide-impregnated prepreg sheet. (d) Forming the prepreg sheet obtained in (c) using a compression molding machine.
It was molded at 350 ° C. and 100 kg / cm ² . The obtained molded product was brown and tough. The tensile strength of this molded product is 10.6 kg.
/ mm ² (23 ℃) (ASTM D-638), bending strength 14.3kg / m
m ² (23 ° C) (ASTM D-790), Izod impact strength (with notch) is 4.2kg ・ cm / cm ² (23 ° C) (ASTM D-
256).

Examples-2 to 6 Polyimide resin powders were generated by using various diamines and tetracarboxylic dianhydrides in the same manner as in Example-1,
Molding was performed using the obtained resin, and the results shown in Table 1 were obtained.

[Table 1]

Comparative Example-1 3,3'-DABP and BTDA under the same conditions as in Example-1.
Was reacted to obtain a polyamic acid solution having an intrinsic viscosity of 0.69 dl / g (0.5 g / 100 ml N, N-dimethylacetamide solvent, 35 ° C.). This solution was diluted with N, N-dimethylacetamide so that the resin content was 8% by weight, and then a glass fiber cloth was immersed. The glass fiber cloth was soaked and then air dried. Do this operation 3
This was repeated to obtain a polyamic acid-containing prepreg sheet. The resulting prepreg sheet was heated and dried at 100 ° C. for 1 hour, 150 ° C. for 1 hour, 180 ° C. for 1 hour, and 220 ° C. for 3 hours to imidize and remove volatile matter to obtain a polyimide-containing prepreg sheet. (a) Molding The obtained prepreg sheets were laminated and molded in the same manner as in Example-1 (d). The tensile strength of this compact is 6.1 kg / mm ²
(23 ℃), bending strength is 7.0kg / mm ² (23 ℃), Izod impact strength (with notch) is 2.4kg ・ cm / cm ² (23 ℃),
It was inferior to Example-1.

Example 7 (a) Polymerization N, N-dimethylacetamide was placed in a 500 ml four-necked flask.
300 ml and 48.33 g (0.15 mol) of BTDA powder were added, and while stirring under a stream of dry nitrogen, 21,23 g (0.
1 mol) and 3,3'-diaminodiphenyl sulfone 12.4
g (0.05 mol) was added slowly. The viscosity of the solution increases with the addition. After the addition was completed, stirring was continued for a further 4 hours to complete the reaction. The obtained polyamic acid was light brown and transparent and had an intrinsic viscosity of 0.67 dl / g (0.5 g / 100 ml N, N-dimethylacetamide solvent, 35 ° C.). (b) Production of polyimide resin powder Acetic anhydride 184 g (1.8 mol), β-picoline 33.6 g (0.36
Mol) and 160 g of N, N-dimethylacetamide in a 1000 ml four-necked flask. 20 ℃ in this solution
The polyamic acid solution obtained in (a) was added dropwise with stirring. After the dropping was completed, stirring was continued for another hour to obtain a pale yellow polyamide resin. This polyamide resin is filtered off from the solvent and imidizing agent, washed with water and methanol, and then kept at 120 ° C.
It was dried under reduced pressure. (c) Impregnation The polyimide resin powder obtained in (b) was applied to a glass fiber cloth (WF-230, manufactured by Nitto Boseki Co., Ltd.) in the same manner as in Example-1 (c) and heat-fused to form a polyimide-impregnated prepreg. The sheet was manufactured. 1 hour at 0 ℃, 30 minutes at 150 ℃, 30 minutes at 180 ℃,
It was dried at 230 ° C. for 1 hour to obtain a polyimide-impregnated prepreg sheet. The fiber content was 58% vol. (d) Example 1 by stacking the prepreg sheets obtained in molding (c)
Molding was performed in the same manner as (d). The tensile strength of this compact is 1
^{0.2kg / mm 2 (23 ℃)} , flexural strength ^{14.8kg / mm 2 (23 ℃)} , Izod impact strength (notched) of 3.7kg · cm / cm ² (23
℃).

Examples-8 to 11 Polyimide resin powders were produced using various tetracarboxylic dianhydrides and diamine compounds in the same manner as in Example-7, and molding and adhesion tests were conducted using the obtained resins. The results shown in Table 2 were obtained.

[Table 2]

Example-12 3,3'-DABP and BTD under the same conditions as in Example-1.
The reaction of A with an intrinsic viscosity of 0.72 dl / g (0.5 g / 100 ml N, N-
A polyamic acid solution in dimethylacetamide solvent, 35 ° C.) was obtained. This solution is mixed with N, N so that the resin content becomes 8% by weight.
-After diluting with dimethylacetamide, a carbon fiber cloth (Torayca cloth 6343) was impregnated. After impregnation, air dry the prepreg sheet, then 100 ° C for 1 hour, 150 ° C for 30 minutes,
It was dried at 220 ° C for 30 minutes. The fiber content of this prepreg sheet was 85% vol. Next, the polyimide resin powder obtained in Example-7 was further applied to this prepreg sheet and heated and melted at 305 ° C. to impregnate the resin. The carbon fiber content in the obtained polyimide-impregnated prepreg sheet was 60.
% Vol. (Molding) The obtained prepreg sheets were laminated and molded in the same manner as in Example-1 (d). The tensile strength of this compact is 73
kg / mm ² (23 ℃), flexural strength 81kg / mm ² (23 ℃), interlaminar shear strength 6.7kg / mm ² (23 ℃)

[0022]

Since the present invention is constructed as described above,
According to the present invention, it is possible to provide a method for producing a laminated molding having excellent heat resistance using a novel prepreg sheet that exhibits particularly excellent strength even at high temperatures.

Claims (4)

[Claims] 1. Formula (1): [In the formula, R ₁ represents an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-bonded group in which aromatic nuclei are interconnected by a bridging member. Represents a divalent group selected from the group consisting of a condensed polycyclic aromatic group and a heterocyclic group,
R ₂ is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-condensed polycyclic group in which aromatic nuclei are interconnected by a bridging member. It represents a tetravalent group selected from the group consisting of aromatic groups and heterocyclic groups, and Y represents a group selected from the group consisting of hydrogen atoms, alkyl groups and aryl groups. ] The organic solvent solution of the polyamic acid having a repeating unit represented by the formula Wherein, R ₁ and R ₂ has the formula (1) is identical to R ₁ and R ₂ in] after coating the polyimide resin powder having a repeating unit represented by the fibrous reinforcing material, of the polyimide A method for producing a laminated molded article, comprising laminating prepreg sheets obtained by heating, melting, and impregnating the glass transition point or higher, and heating under pressure to the glass transition point or higher of the polyimide contained in the prepreg sheet. 2. A fibrous reinforcing material obtained by impregnating a fibrous reinforcing material with an organic solvent solution of a polyamic acid used for obtaining a polyimide resin powder in advance and thermally and / or chemically imidizing the fibrous reinforcing material. The method for producing a laminated molded body according to claim 1, wherein the laminated molded body contains the 3. The polyamic acid is obtained by reacting 3,3′-diaminobenzophenone and 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride in an organic solvent. Or the method for producing a laminated molded article according to item 2. 4. The method for producing a laminated molded article according to claim 1, 2 or 3, wherein the dehydration imidizing agent is at least one selected from acetic anhydride, propionic anhydride, isobutyric anhydride and butyric anhydride.