JP3154437B2 - Phenolic resin composition for carbon-carbon composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a phenolic resin composition having a low viscosity and a high residual carbon content, which is suitable for molding carbon-carbon composites, and a carbon-carbon composite using the phenolic resin obtained in the present invention. It relates to a molded product. By using the resin of the present invention, what has conventionally required a multi-stage impregnation step can obtain an equivalent one by one-stage impregnation, and can greatly reduce labor.

[0002]

2. Description of the Related Art Conventionally, phenolic resins have been used as a raw material for carbon materials, and have also been used for producing carbon-carbon composites. However, the production of carbon-carbon composites of sufficient strength involves impregnation, drying,
It is necessary to perform multi-stage impregnation by repeating the firing step several times, which requires a great deal of cost and labor and is expensive.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a phenolic resin composition having a high residual carbon ratio suitable for producing a carbon-carbon composite and a carbon-carbon composite molded product obtained by using the same. The present invention requires several steps of impregnation, drying, and sintering, thus simplifying the production of an extremely expensive carbon-carbon composite and producing a resin with a high residual carbon ratio that can produce a molded product at low cost. To offer.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a phenolic resin composition having a high residual carbon ratio suitable for producing a carbon-carbon composite and a carbon-carbon composite molded product obtained by using the same. The phenolic resin composition of the present invention has a molar ratio of aldehydes to phenols.
Is 1.0-2.0, and the number average molecular weight is 150-30.
After reacting the resole type phenol resin which is
Alcohol and / or furfural at least 3% by weight
% Or more. As the phenols, phenol, cresol, resorcinol, bisphenol A, and the like can be used. However, any phenol compound that is generally used when synthesizing a phenol resin can be used without particular limitation. Seeds may be mixed and used.

As the aldehydes, formaldehyde, acetaldehyde, benzaldehyde and the like can be used.
There is no particular limitation, and any compound containing an aldehyde group can be used, and a mixture of several compounds may be used. Aldehyde to phenol ratio
(Molar ratio) 1.0-2.0 is appropriate, but 1.2-2.0.
About 1.5 is the best. The reaction time is not particularly limited and can be appropriately changed depending on the intended use and the required properties of the resin.
By setting it to about 300, workability and impregnation are greatly improved. The catalyst used in synthesizing the phenolic resin is not particularly limited, but bases can be used, and the reaction can be appropriately selected according to the required properties of the resin.

[0006] Furfuryl alcohol and / or furfural must be contained in a resol-type phenol resin in an amount of 3% by weight or more, and may be used alone or in combination. If the amount is less than 3% by weight, the viscosity cannot be sufficiently reduced, and it is necessary to reduce the non-volatile content to lower the viscosity. As a result, the residual carbon ratio is reduced, and the hollow portion increases in the carbon-carbon composite in the one-stage impregnation,
Multi-stage impregnation is required to reduce the strength. As described above, a resin having a high residual carbon ratio and good workability needs to have a high non-volatile content and a low viscosity (high impregnation), and furfuryl alcohol and furfural which are both a solvent and a carbon source at the same time It is very effective in achieving high non-volatile content and low viscosity.

[0007]

EXAMPLES The present invention will be described below with reference to examples. In the following, "parts" and "%" all indicate "parts by weight" and "% by weight". Further, the present invention is not limited to the embodiments.

Example 1 1000 g of phenol, 37
In a reaction flask equipped with a stirrer, 35 g of a 10% aqueous solution of sodium hydroxide and 35 g of a 10% aqueous solution of potassium hydroxide are added. After reacting at 85 ° C. for 3 hours, the mixture is dehydrated under vacuum, and 100 g of furfural is added and mixed. Thus, a desired resol-type phenol resin solution was obtained. The obtained resin has a viscosity of 1.2 Pa · s and a non-volatile content of 7 Pa · s.
5%. Table 1 shows the residual carbon ratio of the resin.

Example 2 1000 g of phenol, 37
1000 g of formalin in a reaction flask equipped with a stirrer, 35 g of a 10% aqueous solution of sodium hydroxide and 35 g of a 10% aqueous solution of potassium hydroxide are added, and the mixture is reacted at 85 ° C. for 3 hours and dehydrated under vacuum.
Was added and mixed to obtain a desired resol-type phenol resin solution. The viscosity of the obtained resin was 1.0 Pa · s, and the nonvolatile content was 74%. Table 1 shows the residual carbon ratio of the resin.

<< Example 3 >> 1000 g of phenol, 37
In a reaction flask equipped with a stirrer, 35 g of a 10% aqueous solution of sodium hydroxide and 35 g of a 10% aqueous solution of potassium hydroxide are added. After reacting at 85 ° C. for 3 hours, the mixture is dehydrated under vacuum, and 200 g of furfural is added and mixed. Thus, a desired resol-type phenol resin solution was obtained. The obtained resin has a viscosity of 0.8 Pa · s and a non-volatile content of 7 Pa · s.
5%. Table 1 shows the residual carbon ratio of the resin.

Comparative Example 1 Phenol 1000 g, 37
In a reaction flask equipped with a stirrer, 35 g of a 10% aqueous solution of sodium hydroxide and 35 g of a 10% aqueous solution of potassium hydroxide are added. After reacting at 85 ° C. for 3 hours, the mixture is dehydrated under vacuum, and 100 g of ethanol is added and mixed. The desired resol-type phenol resin solution was obtained.
The viscosity of the obtained resin is 0.7 Pa · s, and the non-volatile content is 74%.
Met. Table 1 shows the residual carbon ratio of the resin.

(Evaluation) The resin solutions of Example 1-3 and Comparative Example 1 were heated to 70 ° C. and impregnated into carbon cloth.
Then, it dried at 130 degreeC for 3 minutes and made it into B stage, and obtained the carbon prepreg. Eight prepregs thus obtained were laminated and press-formed at 130 ° C. and 60 kg / cm ² for 1 hour. The molded laminate was gradually heated in a non-oxidizing atmosphere and fired at 2000 ° C. for 20 hours to obtain a carbon-carbon composite. Table 2 shows changes in weight and bending strength before and after firing.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

As can be seen from the above table, a resin composition having a low viscosity and a high residual carbon ratio can be obtained by using furfural or furfuryl alcohol. Conventionally, impregnation, drying, multi-stage impregnation of repeating the steps of firing is required several times, the production of carbon-carbon composites that required a very large cost, the high carbon residue resin composition of the present invention By using these, it is possible to simplify these steps and perform them by one-stage impregnation, and to produce a high-strength carbon-carbon composite molded product at low cost.

Claims (1)

(57) [Claims] 1. The method according to claim 1, wherein the molar ratio of the aldehyde to the phenol is 1.0 to 2.0, and the number average molecular weight is 150 to
After reacting the resole type phenolic resin of 300, furfuryl alcohol and / or furfural are added at least 3 times.
A resol-type phenolic resin composition for carbon-carbon composites, characterized by being added in an amount of at least% by weight.