JPS62257843A - Composite material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a novel composite material.

(Prior art) Conventionally, a combination of carbon fiber or glass fiber and epoxy resin has been used as a composite material for composites, and composite materials have been created by impregnating woven fabrics, tapes, etc. of these fibers with epoxy resin. A method is adopted in which the composite material is laminated into a desired shape and the epoxy resin is cured under heating and pressure to form a molded product.

By the way, the storage conditions for composite materials using epoxy resins are strict, and it is necessary to store them at -18°C or lower, and the storage period is short, about 3 to 6 months.

In addition, when using a composite material using epoxy resin, it is necessary to raise the temperature from the storage temperature (-18°C or less) to the lamination work temperature at room temperature, and during this temperature rise, moisture accumulates on the surface of the composite material. Dew condensation can cause deterioration in the performance of the resulting molded product, so careful handling of composite materials is required.

Furthermore, as described above, the temperature of the composite material using epoxy resin was raised from the storage temperature to the working temperature, and the required quantity was collected.
Since the remaining composite material is subjected to a thermal cycle to be stored at a low temperature again, the actual shelf life is 3 months or less even if stored at -18°C.

When laminating the composite material to obtain a molded product,
It is necessary to heat and press the laminated composite material in a vacuum state in an autoclave, which requires improvements such as expensive equipment and low productivity.

As seen above, conventional composite materials have various drawbacks.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a new composite material that can be stored for more than one year in a normal room, is unaffected by the cloud atmosphere, and can be subjected to normal heat pressing. .

[Means to solve the problem]

The present inventors have finally arrived at the present invention as a result of intensive studies for the above purpose.

That is, the present invention is a fiber-reinforced composite material characterized by containing a polyimide resin having a repeating unit represented by the formula (I[[).

Furthermore, the above polyimide and I! ? The fiber reinforcing material is impregnated with a polyimide solution consisting of 8 solvents and then desolvated, or
This is a fiber-reinforced composite material characterized in that a fibrous reinforcing material is impregnated with the polyamic acid shown in /) or a solution containing the polyamic acid, and then heated to convert the impregnated polyamic acid into a polyimide.

The polyimide solution used in the present invention or the polyamic acid solution which is its precursor can be obtained by the following method.

That is, 2,2-bis(4-(3-aminophenoxy)phenyl)propane and 3.3°, 4°, 4°-benzophenone tetracarboxylic dianhydride are polymerized in an organic solvent to form a polyamic acid solution. In addition, to obtain polyimide, 1 volume of the above polyamic acid is mixed with 100~
Polyimide is obtained by heat dehydration at 400° C. or chemical dehydration by treatment with a commonly used imidizing agent, such as acetic anhydride, triethylamine, or a terminal stopper, such as phthalic anhydride. A polyimide solution is obtained by dissolving it in a suitable solvent. Moreover, when the produced polyimide is dissolved in the polymerization solvent, it can be used as it is as a polyimide solution.

Regarding 2,2-bis(4-(3-aminophenoxy)phenyl)propane according to the present invention, JP-A-59-1
70.122 briefly states that a dinitro compound is obtained by the reaction of tochloronitrobenzene and 2,2-bis(4-hydroxyphenyl)propane, and then this is reduced, but the melting point etc. , there is no description of the physical properties that confirm the structure.

The logarithmic viscosity of polyamic acid, which is a precursor of polyimide used in the present invention, is 0.01 to 3.0 dlt7
g, preferably 0.05 to 2.5 d j!
/g, more preferably 0.1 to 1.5d
It is 17g.

The polyamic acid production reaction described above is usually carried out in an organic solvent. Examples of the organic solvent used in this reaction include 1JdJ-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N
-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone,
N-methylcaprolactam, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis(2-(2-methoxyethoxy)ethyl)ether, tetrahydrofuran, Examples include 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, etc. These growth solvents may be used alone or in combination of two or more. There is no problem in using it.

The reaction temperature is usually 60°C or lower, preferably 50°C or lower.

The reaction pressure is not particularly limited, and the reaction can be carried out at normal pressure.

The reaction time varies depending on the type of solvent and reaction temperature, but it is a sufficient time for polyamic acid to be produced, and is usually 4.
~24 hours.

Such a reaction yields a solution of polyamic acid in an organic solvent.

In addition, the am solvent solution of polyimide can be prepared by heating or chemically dehydrating the polyamic acid, and adding the polyimide to a suitable solvent, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl- 2-
Pyrrolidone, tetrahydrofuran, sulfolane, 1,3
- Dimethyl-2-imidazolidinone, p-chlorophenol, chloroform, dichloromethane, dichloroethane, trifluorethane, ethylbromide, tetrabromoethane, and other halogenated hydrocarbons, cresol, cyclohexanone, isophorone, etc., obtained by dissolving the compound.

Moreover, when the produced polyimide is dissolved in the polymerization solvent, it can be used as it is as a polyimide solution.

The amount of solvent to be used is determined so that the viscosity of the solution when polyamic acid or polyimide is dissolved is in the range of 10 to 4000 centiboise at room temperature. If the void is less than 10 cm, it is difficult to remove the solvent after impregnating the fibrous reinforcing material.
000 centipoise or more, on the other hand, the impregnability of the fibrous reinforcing material deteriorates, making the work difficult.

Typical fibrous reinforcing materials include glass fibers, carbon fibers, aromatic polyamide fibers, silicon carbide fibers, alumina fibers, boron fibers, metal fibers, etc., and these fibers may be used alone or in combination. Furthermore, other reinforcing materials such as potassium titanate fibers, mica, and calcium silicate may also be used in combination with the fibers, if necessary.

The fibrous reinforcing material is impregnated with a polyamic acid solution or a polyimide solution. In this case, all known methods can be used.
~ 500 centipoise) after soaking in a polyamic acid solution or polyimide solution, air drying, and then drying with relatively high viscosity (about 500 centipoise).
It is preferable to immerse the material in a polyamic acid solution or a polyimide solution (approximately 100 to 4000 centivoids) because a uniform composite material with many impregnated types can be obtained.

When using a polyamic acid solution, heat treatment is performed to remove the solvent from the impregnated fibrous reinforcing material and at the same time to imidize it. In this case, bubbles may be generated due to the dehydration reaction caused by imidization, so it is desirable to sufficiently control the temperature increase rate. Usually, the polyimidation temperature is in the range of 100 to 400 degrees Celsius, preferably 100 to 250 degrees Celsius. Although the rate of temperature increase varies depending on the solvent used and the conditions such as when processing under normal pressure or reduced pressure, 2 to b minutes is usually appropriate. The heat treatment time varies depending on the polyimidation temperature, desired imidization rate, etc., but one minute to several hours is sufficient. Furthermore, when using a polyimide solution, it can be used as a composite material by simply removing the solvent after impregnating the fibrous reinforcing material.

The solvent may be removed at room temperature or by heat treatment, but care should be taken to ensure that no bubbles remain when removing the solvent.

The composite material obtained as described above can be laminated and heated and compressed to produce a molded product of a desired shape.

The heating temperature during lamination molding may be 250°C or higher, preferably 300°C to 400°C.

In addition, although the pressurizing pressure varies depending on the shape, it is usually LOKg/c
11 or more is sufficient.

The composite material of the present invention can be stored indoors at room temperature for more than one year, and can be laminated indoors.

In addition, the above-mentioned molding process is easy, and ordinary hot press molding can be used without using an autoclave, which is required when using composite materials using epoxy resin, which has the effect of reducing molding costs. can get.

〔Example〕

Hereinafter, the present invention will be explained in detail using Examples, Comparative Examples, Synthesis Examples, and Reference Examples.

Reference Example: Ullmann reaction in which tochloronitrobenzene and 2,2-bis(4-hydroxyphenyl)propane are condensed in an amine solvent under a copper catalyst and heated in an aprotic polar solvent in the presence of a base. However, the reaction did not proceed at all in any of the methods, and 2,2-bis(4-(3-aminophenoxy)phenyl)propane could not be obtained.

Synthesis example 2.2-1? -S(4-(3-aminophenoxy)phenyl)propane was synthesized as follows.

85.6 g (0.38 mol) of 2,2-bis[4-hydroxyphenyl]propane in a 2.000 ml glass container
, m-dinitrobenzene 151.2 g (0.9 mol),
Charge 124.6 g of potassium carbonate and 660 ml of N,N-dimethylformamide, and heat at 145 to 150°C.
React for 0 hours. After the reaction is complete, cool and filter the solid matter.
Next, the solvent was distilled off from the filtrate by one distillation under reduced pressure, and then 65
The mixture was cooled to ℃, charged with 450 ml of methanol, and stirred for 1.0 hour. The crystals were filtered, washed with water, methanol, and dried to obtain yellowish brown crystals of 2°2-bis(4-(3-nitrophenoxy)phenyl)propane. Yield: 164.8
g (yield 93.5%), the crude crystals were recrystallized with methyl cellosolve to obtain a pure product.

Pale yellow prismatic crystal +1+9 111~113℃
C1 (N Elemental analysis Calculated value (χ) 168.93 4.71 5.
96 analysis value α) 69.05 4.65 5.94
book) CzJttNzOa MS: 470 (M”), 455 (M-C1 (ff
)"IR(niBr, ell-'): 1520 and 1
340 (No, group) 1240 (ether bond) 1,000 In a closed glass container, crude 2,2-bis[4-(3-nitrophenoxy)phenyl]propane 1
00g (0.21 mol) is charged together with 5χPd/C5,Og and methyl cellosolve 3001. 60-65℃
Introduce hydrogen while stirring vigorously. Absorption stopped in 8 hours and the reaction was completed.

After cooling, the catalyst was removed and methyl cellosolve 150
Distill n+1. Add 12,270 g of 20% salt, further add 30 g of common salt, and cool to 20 to 25° C. while stirring to precipitate crystals. This is filtered and neutralized with aqueous ammonia in 30% isopropanol to precipitate crystals. After filtering, washing with water and drying, remove the benzene.
Recrystallized from a mixed solvent of hexane to give 2.2-his(4-
(3-Aminophenoxy)phenyl]propane was obtained.

Yield 69.2g (Yield 80χ) Colorless crystals mp, 1
06-b Purity 99.52 (by high performance liquid chromatography) C) IN Elemental analysis Calculated value (χ) 79.02 6.34 6.
83 analysis value (χ) 79.216°40 6.71 rate”)
CtJzbNzOb MS: 410 (M”), 395 (M-CHi)
"rR(KBr, am-'): 3460 and 3
370 (Nnz group) 1220 (ether bond) Example 1 41.0 g of 2,2-bis(4-(3-aminophenoxy)phenyl)propane ( 0.1 mol) and N, N-
219.6 g of dimethylacetamide was charged, and 31.6 g (0,098 mol) of 3,3°14,4"-benzophenonetetracarboxylic dianhydride was added in small portions as a dry solid under a nitrogen atmosphere at room temperature. The mixture was added and reacted to obtain a solution containing 23% by weight of polyamic acid.

The polyamic acid solution was further diluted with N,N-dimethylacetamide to obtain a solution having a concentration of about 10% by weight.

A carbon fiber woven fabric (Torayca Cloth+16343° trademark) was dipped in this solution, air-dried, and then dipped in a 23% by weight polyamic acid solution and air-dried three times, until the amount of polyamic acid attached was 40% by weight. I made it happen.

A carbon fiber woven fabric with a polyamic acid adhesion amount of 4% and 1% was heated to 220°C at a heating rate of 7°C/min in a nitrogen atmosphere, and heated at that temperature for 1 hour to form a polyimide with a thickness of 0.
A composite material of 32 ma+ was obtained.

The resulting composite material was heated to -18°C, 20°C, and 120°C.
After storing for 30 days under the conditions of '417@l at room temperature,
After vacuum drying to remove moisture etc., 10 sheets of the composite material under each storage condition were stacked and stored at 330℃ and 100Kg.
/cJ for 20 minutes, 200 x 2
I got a flat plate of 00X 3m+w. The bending strength of this flat plate was 75Kg/mm'' and 13Kg/mm'' under each storage condition.
, 78 Kg/mm'', and there was almost no difference between the storage conditions and the bending strength.

From the above, it is possible to store the product at a temperature of 20° C. or higher without condensation of moisture or other condensation.

Example 2 After obtaining a polyamide tRig t& in the same manner as in Example 1, acetic anhydride and triethylamine were used as a dehydrating agent, and the mixture was added dropwise to dissolve while stirring, and then drained into water and the precipitate was separated by filtration. .

It was washed with methanol and dried under reduced pressure to obtain polyimide powder. This polyimide powder was dissolved in N-methyl-2-pyrrolidone to give polyimide solutions of 10% by weight and 20% by weight, respectively.

Similar to Example 1, carbon fiber woven fabric (Tracking Card Cloth 8634
3. After repeating the process of first immersing (trademark) in a 10% by weight polyimide solution and air drying, then immersing it in a 20% by weight polyimide solution and air drying three times, it was heated to 200°C at a heating rate of 10°C. After raising the temperature, it was heated for 1 hour to obtain a composite material with a polyimide adhesion amount of 40% by weight and a thickness of 0.32 m+++.

The obtained composite material was stored in the same manner as in Example 1, and then molded under the same conditions to obtain a flat plate. The bending strength of each flat plate is 79
Kg/i11", 14Kg/ma+", 77Kg/ms
', and there was almost no difference between the storage conditions and the bending strength.Example 3 Phthalic anhydride was added dropwise to the polyamic acid solution used in Example 1 and stirred, and then under the conditions shown in Example 2. imidization with
An end-blocked polyimide powder was obtained, an imide solution was prepared, the solution was dipped into a carbonate fiber fabric, air-dried, and the solvent was removed to obtain a composite material.

The composite material was further treated under the same storage conditions as shown in Example 1, and then molded under the same conditions to obtain a flat plate.

The bending strength of the flat plate is 74Kg/m+w” and 78Kg/m, respectively.
There was almost no difference between the storage conditions and the bending strength, which was 75 Kg/mm".

Example 4 The polyamic acid solution used in Example 1 was applied to a glass fiber woven fabric (Nittobo Glass Fiber F3) under the same conditions as Example 1.
50), air-dried, and further heat-treated to obtain an imidized composite material with a thickness of 0.32 ma+.

The composite materials were further treated under the same storage conditions as described in Example 1 and molded under the same conditions, and the bending strength of each flat plate was 58 g/m.
J, 63Kg/am", 60Kg/ms",
There was little difference between storage conditions and bending strength.

Example 5 A composite material was obtained in the same manner as in Example 4 except that an aromatic polyamide fiber woven fabric (manufactured by DuPont, Kevlar 49 aramid fiber) was used as the fibrous reinforcing material. The obtained composite material was stored and then molded in the same manner as in Example 1 to obtain a flat plate. The bending strength of the obtained flat plates was 41 kg/mm.
", 35Kg/mm", 46 to 17mm",
There was little difference between storage conditions and bending strength.

〔Effect of the invention〕

The composite material of the present invention can be stored at low temperature (-18℃) like conventional products.
(below) and can be stored at room temperature. For this reason, there is no need to raise the temperature from the storage temperature to the room temperature lamination work temperature as in the past, and therefore, there is no fear of condensation of moisture or the like on the surface during the lamination work, and the work can be carried out with peace of mind. Furthermore, it has great industrial utility effects, such as being able to be molded using a normal hot press.

[Brief explanation of drawings]

FIG. 1 is an example of an infrared absorption spectrum diagram of polyimide powder used in the present invention.

Claims (3)

[Claims] (1) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ A composite material made of polyimide and a fibrous reinforcing material that has a repeating unit represented by (I). (2) Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼It is characterized by impregnating a fiber reinforcing agent with a polyimide solution consisting of a polyimide having a repeating unit represented by (I) and an organic solvent, and then removing the solvent. A method for manufacturing a composite material. (3) A polyamic acid having a repeating unit represented by formula (II) ▲ ▲ Numerical formula, chemical formula, table, etc. ▼ (II) which is a precursor of polyimide shown in formula (I) in the first claim, Or, a method for producing a composite material, which comprises impregnating a fiber reinforcing material with the solution and then heating it to form a polyimide.