JPS6221872A - Carbon fiber for reinforcing polyimide resin - 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 (Technical Field) The present invention uses polyimide resin as a matrix material (base material).
The present invention relates to carbon fibers that have excellent adhesion to matrix resins at high temperatures and excellent processing stability in carbon fiber reinforced materials.

<Background technology> In recent years, carbon cords have been developed with high strength, high elastic modulus, and a specific gravity of 1.
．． 6 to 1.9, it is composited with matrix materials such as thermosetting or thermoplastic plastics in the form of fiber bundles (strands) or chops, and is mainly used in the fields of aircraft, automobiles, and sporting goods. It is widely used.

In particular, carbon fiber reinforced materials using polyimide resin as a matrix material are expected to be used in areas that require high temperatures because the resin has very good heat resistance.

For example, members around the engine are a typical example. However, the commonly used carbon fiber cups? When used as a reinforcing material for polyimide resin, the sizing agent that is attached to maintain workability gasifies at high temperatures and has poor heat resistance, so the physical properties of the resulting reinforced material at high temperatures, especially the adhesive properties It had the disadvantage of being inferior to

For this purpose, carbon fibers using heat-resistant resin as a sizing agent have been considered, but such carbon fibers tend to generate fuzz during processing, and the sizing agent itself changes over time, resulting in poor processability. It had the disadvantage of being unstable.

(Problems to be solved by the invention) The present inventors have investigated a sizing agent-attached carbon fiber that can be used in a polyimide matrix resin and has excellent heat resistance, processability, and stability, and has solved the above-mentioned drawbacks. , which led to the present invention.

(Structure and operation of the invention) The present invention provides a sizing agent composition containing a polymaleimide represented by the general formula (1) and an epoxy resin and having a viscosity of 10 to 5 x 10'' poise at 50°C. It is a polyimide-based resin-reinforcing carbon fiber with a weight of ~5% by weight.

Particularly desirably, the sizing composition has a polymaleimide content of 15% or more, and a weight loss of 5% when treated in air at 230° C. for 1 hour. These are as follows.

The polymaleimide used in the present invention is produced by reacting an aromatic amine at a ratio of 2 to GO moles with respect to 1 mole of aromatic dialdehyde, adding 17 polyamine and maleic anhydride to form polyamic acid, which is then dehydrated. Obtained by cyclization.

Here, the aromatic aldehyde is 1,2-benzenedialdehyde, 1,3-benzenedialdehyde, or 1,4-benzenedialdehyde represented by the general formula, and preferably 1,4-benzenedialdehyde from the viewpoint of heat resistance. It is a dialdehyde.

Further, aromatic amines include aniline, 0-toluidine, totoluidine, and P-toluidine, and aniline is usually preferred.

The polymaleimide in the present invention may be a reaction product containing 60% by weight or more of the compound represented by the general formula (1), or may be an extracted and purified product of this reaction product.

The epoxy resin used in the present invention is usually diglycidyl ether of bisphenol A1 bisphenol F1 bisphenol S, and its commercial product is Epicote 827.
, 828, 834 (manufactured by Yuka Shell Epoxy Co., Ltd.) with an epoxy equivalent of 100 to 230, and phenol novolac epoxies, such as Epicote 1.
52, 154 (manufactured by Yuka Shell Epoxy Co., Ltd.), Araldite EPN1138 (manufactured by Ciba Geigy Co., Ltd.) and other epoxy equivalents of 170 to 182, urethane-modified epoxy resins, and their products include Adekal Resin EPV-6, E
PV-6A (Asahi Kaisha'l) Epoxy equivalent 210
~250, one or more of these, [
It is. Epoxy resins made from other amine compounds are not preferred because the hardness of the trjA material changes over time and processability deteriorates.

In the present invention, a known nonionic surfactant consisting of a polymaleimide, an epoxy resin and, if necessary, a surfactant exhibiting lubricity of up to 10% by weight, such as a polyether adduct of an aliphatic or aromatic alkyl, is used. Improving sex 1 =
Polymaleimide is applied to carbon fibers in the form of a mixture mixed with polyvinyl alcohol etc. such that the viscosity at 50°C is 10 to 5 x 10" poise, and it is preferable that the mixture contains 15% by weight or more of polymaleimide. .

If it is less than 15% by weight, the heat resistance of the molded product tends to be poor, which is not preferable. If the viscosity of the mixture at 50° C. is less than 10 voices, the carbon fibers to which the mixture is attached will not have sufficient cohesiveness, resulting in poor processability, which is not preferred. In addition, if the voice exceeds 5 x 10', it is preferable because it will lead to poor impregnation of the polyimide matrix resin into the carbon fibers to which the mixture is attached, and the physical properties at high temperatures of the obtained molded product, especially the interlaminar shear strength (ILSS), will become low. do not have.

It is preferable that the weight loss of the mixture after being treated in air at 230° C. for 1 hour is 5% or less.

If it exceeds 5%, the high-temperature physical properties of the molded product will deteriorate as described above.

The higher the proportion of polymaleimide in the sizing composition, the less the weight loss will occur, but the amount of weight loss will depend on the type of epoxy resin, lubricity, surfactant, and matrix and type of focusing compound added. It is desirable to appropriately select the content of the polymaleimide since it is costly.

The attachment method is to melt the polymerimide, epoxy resin, and additives if necessary in a kneader, etc.
Alternatively, each individual may be added to a good solvent such as acetone, methyl ethyl ketone, tetrahydrofuran, etc. at a concentration of 1.0 to 100%.
Carbon fibers are immersed in a solution obtained by dissolving ζ to a concentration of 1/R or sprayed with the solution to achieve a coating weight of 0.1 to 5% by weight (relative to the total weight). Attach as desired.

If the amount of adhesion is less than 0.1% by weight, the processability of carbon mta will be poor, which is not preferable. In addition, if it exceeds 5% by weight, it is not preferable because the impregnation of the matrix resin into carbon 1a miscellaneous particles during molding will be reduced and the physical properties of the molded product at high temperatures, especially the interlaminar shear strength, will be low. .

The carbon fiber used in the present invention has a carbon content of 85.4%.
Above, acrylonitrile fiber or pitch mm
It consists of single fibers with a diameter of 0.1 to 20 microns and a number of constituent fibers of 100 to 10,000,000,000,000,000,000,000,00000000000000000000000000000000000000000000 form form type form type type form type form form type form. ) is a fiber bundle.

The sizing agent-attached carbon fiber of the present invention is made of polyimide matrix resin such as polyimide resin (trade name, PMR-
11, LARK, etc.), triazine-based bismaleimide resin (trade name, [3T resin), N , N = -4
, 4--diphenylmethane bismaleimide and other polymaleimide resins and polyetherimide resins are used in the form of long m fibers or single #a fibers.

(Effect of the invention) Sizing agent-adhered carbon of the present invention! &! Miscellaneous fibers have excellent heat resistance, are easy to handle when processing fibers into woven fabrics, knitted fabrics, and sheet materials, and have excellent processability in that they can be operated smoothly without generating fuzz, and are stable even after long-term storage. Because the fiber has such processability, it can be combined with a heat-resistant resin, particularly a polyimide resin whose heat distortion temperature is 200° C. or higher, to form a heat-resistant composite material with excellent physical properties at high temperatures.

Therefore, it can be used in place of metal, which has conventionally been used as a material for parts exposed to high temperatures in engines, etc., and is suitable for achieving energy savings through weight reduction.

Ij (Implementation? and comparative example) The present invention will be explained in more detail by giving examples.

Unless otherwise specified, "%" [parts] are not expressed by weight.

Example 1 Polyamine obtained from 1.4-benzenedialdehyde (0.44 mol) and aniline (2.6 mol) <softening point 11
5-121℃, neutralization equivalent 118, perchlorine 11 titration method)
A reaction product (softening point: 160 to 180°C) was prepared by reacting 94.4 g of maleic anhydride with 78.6 g of maleic anhydride. This reaction product contained 68% of the polymaleimide compound represented by formula (3). 35% of this reaction product and 65% of Epicote 82B (manufactured by Yuka Shell Epoxy Co., Ltd.), which is a diglycidyl ether of bisphenol A, were mixed, and the resulting mixture was dissolved in acetone to a concentration of 1.5%. This is carbon fiber (strength 4.2G) consisting of 6000 pieces with a diameter of 7 microns.
Pa, elastic modulus 250 GPa>, 80% of the solution adhered to the fibers, and dried at 130°C. From the obtained carbon￥aM1,
When the adhering mixture was extracted by acetone reflux extraction method, it was 97311.1111%, and the extracted mixture was measured using a viscosity measuring device (Rheometrics RD-7).
700 type), the viscosity was 13 at 50°C.
It was 00 poise.

The carbon mst bundle with the above mixture attached was placed in an air m/m at 25°C.
The processability was determined by the fuzz condition of the fiber surface when rolled up in minutes, and the heat resistance of the acetone reflux extract (inner diameter 45
mm, i! In addition to investigating the oxidation weight loss when 1 gram of the object to be measured was placed in a 3-inch somm and treated in air at 230°C for 1 hour, Combimite H-800 (manufactured by Technochem Co., Ltd.), a bismaleimide resin, was investigated. A molded plate (
Thickness t) 1 mm, m fiber volume content (vf) 60%] was further heated at 210°C for 15 hours, and the interlaminar shear strength (I
The measuring device used to measure L SS ) was an Instron universal testing machine, and the measuring method was ASTM D-2344).

As shown in Table 1, the fibers had good processability and good processability even after long-term storage.Furthermore, the sizing agent had good heat resistance and the molded product had good adhesion at high temperatures (rLs).
s) was also excellent.

Table 1 Examples 2 to 3 and Comparative Examples 1 to 3 A mixture of 1 q of the polymaleimide obtained in Example 1 and Epicoat 152 (manufactured by Yuka Shell Epoxy Co., Ltd.), which is a phenol novolak type epoxy resin, as shown in Table 2. Carbon fibers were obtained in the same manner as in Example 1 except that the sizing agent was used. Table 2 shows the results of examining the properties of the fibers.
show.

In the case of the range of the present invention, the processability of the fiber is good, and it also shows good processability even after long-term storage, as well as the heat resistance of the sizing agent and the adhesion of the molded product at high temperatures Examples 4 to 5 Example 1 A mixture of polymaleimide and tetraglycidyldiaminophenylmethane (manufactured by Ciba Geigy, Araldite MY-720) as shown in Table 3 was used as the sizing agent (A), and tetraglycidyldiamino A carbon miscellaneous material was obtained in the same manner as in Example 1, except that phenylmethane was replaced with a diglycidyl ether agent (B) of bisphenol A.

Table 3 shows the results of investigating its properties.

Table 3 Example 6 In Example 2, polyoxyethylene (n-10) lauryl ether having lubricity was added as an additive at 1.5.1 parts per 100 parts of the mixed system of polymaleimide and epoxy resin.
* Oxidation reduction I in the same manner as in Example 1.
The juice was measured.

The results were 2.3, 2.5, and 2.7%, respectively, which were good values. The viscosity of the obtained sizing agent composition was 1゜2X10'', 1.Ox 10◆, 7,OX
It was 10” poise.

The sizing agent composition was adhered to carbon lJA fibers in an amount of 11.5% in the same manner as in Example 1, and various properties were measured.

Changes in the hardness of the m string bundle after 6 months! There was no change in the processability of IN after 6 months, and the ILSS of the molded product was 12.3 GPa when measured at 25°C and 5 when measured at 250°C.
It was ゜3GPa.

Patent applicant: Eastern Bethlon Hayashiki Company Representative Patent Attorney, Third Department Procedural amendment September 140, 1985

Claims (3)

[Claims] (1) General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (Here, R: ▲There are mathematical formulas, chemical formulas, tables, etc.▼) Polymaleimide and epoxy resin shown by Carbon fibers for reinforcing polyimide resin to which 0.1 to 5% by weight of a sizing agent composition containing 10 to 5 x 10^4 poise and having a viscosity of 10 to 5 x 10^4 poise at 50°C is adhered. (2) The content of polymaleimide in the sizing agent composition is 1
The carbon fiber for reinforcing polyimide resin according to claim (1), which contains 5% by weight or more. (3) Claims (
1) Carbon fiber for reinforcing polyimide resin.