JP2014098081A - Thermosetting resin composition and fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of swelling on the surface of a fiber reinforced composite material when a pot life is long and waste of the curable composition can be reduced and a fiber reinforced composite material is impregnated into a fiber base material. To provide a curable resin composition and a fiber-reinforced composite material using the same.
A resol type phenol resin composition comprising a water soluble resol type phenol resin (A), a solvent (B) having a boiling point of 110 to 300 ° C. and water, and having a pH of 8 to 13. A fiber-reinforced composite material obtained by impregnating a fiber substrate with the resol type phenolic resin composition and curing it.
[Selection figure] None

Description

  The present invention has a long pot life, can reduce excessive waste of the curable composition, and when impregnated into a fiber base material to obtain a fiber-reinforced composite material, the surface of the fiber-reinforced composite material is unlikely to generate bulges. The present invention relates to a thermosetting resin composition and a fiber-reinforced composite material using the same.

  The resol type phenol resin has excellent heat resistance, adhesiveness, mechanical properties, electrical properties, price advantages, and the like. Therefore, resol-type phenolic resins are used as composite materials by adding fillers such as organic and inorganic mats and cloths, powders, thermosetting accelerators, mold release agents, plasticizers, etc. It is used for applications such as parts, ducts, ceiling materials, wall materials, tanks and pipes. In recent years, the above-mentioned excellent properties have been refocused, and resol type phenol resins are used to produce fiber reinforced composite materials by impregnating and heat curing fiber substrates such as glass substrates and carbon nanofibers. As these fiber-reinforced composite materials, specifically, conductive composites by compounding with carbon nanofibers, fuel cell separators, insulating layers of electric double layer capacitors, and the like have been widely studied.

  A fiber reinforced composite material using a resol type phenol resin is usually a composition in which an organic acid such as paratoluenesulfonic acid is added as a curing catalyst to a resin composition containing a resol type phenol resin, and this is used as a fiber base material. Manufactured by impregnating and curing. In this production method, since the resol type phenolic resin begins to be cured by the addition of the curing catalyst, the resin composition is solidified in the supply line unless the entire amount is used within a few minutes to several tens of minutes after the curing catalyst is added. There is a problem.

  As a resol type phenol resin composition having a long pot life (long pot life), for example, it contains a resol type phenol resin and an acid, and the resol type phenol resin uses an aldehyde, a phenol and an alkaline substance as a catalyst. A resol-type phenol resin composition is disclosed, which is a resol phenol resin obtained by reacting and neutralizing a remaining alkaline substance with an acid having a pKa of 0 or less and an acid having a pKa of 1 or more. (For example, refer to Patent Document 1). The resol type phenol resin composition disclosed in Patent Document 1 has a pot life of about 70 minutes after the addition of the curing catalyst. However, the resol-type phenolic resin composition disclosed in Patent Document 1 must be prepared on the day of use, and any composition that cannot be used on the day must be discarded. It is regarded as a problem. Therefore, there is a need for a resol type phenolic resin composition having a longer pot life.

  In addition, the resol-type phenolic resin composition is required to be aqueous from the viewpoints of the environment and occupational safety and health. However, the water-based resol type phenolic resin composition is gasified by heat applied at the time of curing, so that there is a problem that swelling and deformation of the surface of the obtained fiber composite reinforcing material occur. In order to prevent the swelling and deformation, for example, it is necessary to perform special treatment such as curing drying at room temperature for about 24 hours or multi-stage pressing, which deteriorates the production efficiency.

JP 2004-091600 A

  The problem to be solved by the present invention is to provide a molded article such as a fiber composite reinforced material having a long pot life, reducing excessive waste of the curable composition, and having no blister on the surface without reducing the production efficiency. The object is to provide a resol-type phenolic resin composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors set the pH of the composition containing a water-soluble resol-type phenol resin to 8 to 13 to achieve good curing and do not require a catalyst or the like. Since it becomes a composition, the pot life becomes long, and by adding a solvent having a boiling point higher than water, specifically, a solvent having a boiling point of 110 to 300 ° C., about 24 hours at room temperature. The inventors have found that a molded product such as a bulge or a fiber composite reinforced material having no deformation can be obtained without performing special treatment such as curing and drying or multistage pressing, and the present invention has been completed.

  That is, the present invention comprises a water-soluble resol-type phenol resin (A), a solvent (B) having a boiling point of 110 to 300 ° C., and water, and having a pH of 8 to 13 A composition is provided.

  The present invention also provides a fiber-reinforced composite material obtained by impregnating a fiber substrate with the resol-type phenol resin composition and curing it.

  The resol type phenolic resin composition of the present invention is excellent in curability by heat without adding a curing catalyst, and a cured product can be obtained as a one-pack type composition. Therefore, the composition is excellent in pot life. In addition, by using the resol type phenolic resin composition of the present invention, a fiber-reinforced composite material with no blistering on the surface is provided without special treatment such as curing drying at room temperature for about 24 hours or multistage pressing. can do.

  The water-soluble resol type phenol resin (A) used in the present invention can be obtained, for example, by reacting an aldehyde and a phenol in the presence of an alkali metal hydroxide using a catalyst. The alkali metal hydroxide used as the catalyst forms a phenolate with a hydroxyl group of the phenol resin, thereby making it water-soluble.

  Examples of the aldehydes include formaldehyde such as formaldehyde, paraformaldehyde, and trioxane; acetaldehyde and the like, and urotropine can also be used. Among these, formaldehyde is preferable in terms of performance and economy. One type of aldehyde may be used, or two or more types may be used in combination.

  Examples of the phenols include phenols; alkylphenols such as cresol, xylenol, ethylphenol, butylphenol and octylphenol; polyhydric phenols such as resorcin and catechol; halogenated phenols, phenylphenols and aminophenols. Among them, phenol is preferable because a resol-type phenol resin having excellent curability and water solubility can be obtained and it is excellent in economic efficiency. One type of phenols may be used, or two or more types may be used in combination.

  Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, and the like. Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable because they are easily available and are excellent in economy. The alkali metal hydroxide used in the present invention may be a hydrate.

  The amount of aldehydes and phenols used is 1.0 / 1.0 to 3.0 / 1.0 in terms of molar ratio [aldehydes / phenols] because the water-soluble resol-type phenol resin (A) is easily obtained. preferable. Moreover, 0.05 mol-0.5 mol are preferable with respect to 1 mol of phenol, and, as for the quantity of the alkali metal hydroxide used as a catalyst, 0.1-0.4 are more preferable.

  The reaction temperature of aldehydes and phenols in producing the water-soluble resol type phenol resin (A) is usually 40 to 100 ° C. Moreover, reaction time is 1 to 12 hours normally.

  The resol type phenolic resin composition of the present invention has a pH of 8-13. In order to adjust the pH to 8 to 13, the pH of the water-soluble resol type phenol resin (A) may be previously set to 8 to 13, or the water soluble resol type phenol resin (A), the solvent (B) and If necessary, after mixing water, the pH may be adjusted to 8-13. Examples of the alkaline compound used for adjusting the pH include alkaline earth metals such as calcium hydroxide and barium hydroxide in addition to alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide. Hydroxides; alkali metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, and cesium carbonate; amines such as ammonia, triethylamine, and hexamethylenetetramine can be used.

  When using an aqueous solution of the water-soluble resol-type phenol resin (A) as the water-soluble resol-type phenol resin (A) used in the present invention, the amount of active ingredients that can be applied at one time increases, and the resin is excellent in productivity and economy. An aqueous solution of a resol type phenol resin (A) having a solid content concentration of 60% or more is preferable.

  The water-soluble solvent (B) used in the present invention has a boiling point of 110 to 300 ° C. By containing the water-soluble solvent (B), it is possible to efficiently release a large amount of water vapor generated during curing to the outside of the cured product, so that a fiber-reinforced composite material having no blister on the surface is obtained. Examples of the water-soluble solvent (B) include hydroxyalkyl group-substituted cyclic ethers such as tetrahydrofurfuryl alcohol;

Ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 2 -Methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, glycerin, diglycerin, acetylene Polyhydric alcohols such as diols;

Monoethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether, ethylene glycol monophenyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, polyethylene glycol monomethyl ether Alcohols;

Diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, polyethylene glycol dimethyl ether, tetraethylene glycol Diether glycols such as dimethyl ether;

Examples include ethylene glycol monomethyl ether acetate and ethyl lactate. The water-soluble solvent (B) is preferably a solvent having a boiling point of 150 to 300 ° C., is easily available, and is excellent in economic efficiency, so that it is one or more selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol. A water-soluble solvent is preferable, and diethylene glycol is more preferable.

  As content of the organic solvent (B), 0.1 to 20 parts by mass with respect to 100 parts by mass of the water-soluble resol type phenol resin (A) is excellent in drying property, and the physical properties of the obtained cured product are not easily lowered. The resol type phenol resin composition is preferable because it is obtained, and 1 to 15 parts by mass is more preferable.

  The resol-type phenol resin composition of the present invention can be obtained, for example, by mixing an aqueous solution of a water-soluble resol-type phenol resin (A) and a water-soluble solvent (B) having a boiling point of 110 to 300 ° C. As described above, the pH may be adjusted to 8 to 13 after mixing, or may be adjusted to 8 to 13 at the time of the aqueous solution of the water-soluble resol type phenol resin (A).

  Divalent phenols may be added to the resol type phenol resin composition of the present invention in order to improve curability. Examples of the divalent phenols include resorcin, catechol, hydroquinone, 2,2-bis (4′-hydroxyphenyl) propane, 1,1′-bis (dihydroxyphenyl) methane, and 1,1′-bis (dihydroxy). Naphthyl) methane, tetramethylbiphenol, biphenol, hexamethylbiphenol, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1 , 7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, naphthalenediols such as 2,7-dihydroxynaphthalene, and the like.

  The resol type phenolic resin composition of the present invention provides a coupling agent that imparts adhesion to a fiber substrate, a flame retardant that imparts flame retardancy to a fiber reinforced composite material, and a releasability from the mold. A mold release agent, etc. can be mix | blended in the range which does not impair the effect of this invention.

  As said coupling agent, a silane coupling agent, a titanate coupling agent, etc. are mentioned, for example, A silane coupling agent is preferable. Examples of the silane coupling agent include silane coupling agents having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycid Silane coupling agents having an epoxy group such as xylpropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane;

Silane coupling agents having a styryl group such as p-styryltrimethoxysila; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxy Silane coupling agent having a methacryl group such as propyltriethoxysilane; Silane coupling agent having an acrylic group such as 3-acryloxypropyltrimethoxysilane;

N- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3 -Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- ( Silane coupling agents having an amino group such as hydrochloride of vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane;

Silane coupling agents having a ureido group such as 3-ureidopropyltriethoxysilane; Silane coupling agents having a mercapto group such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; Bis (triethoxy Silane coupling agents having a sulfide group such as (silylpropyl) tetrasulfide; Silane coupling agents having an isocyanate group such as 3-isocyanatopropyltriethoxysilane. One type of these coupling agents may be used, or two or more types may be used in combination.

  Examples of the flame retardant include phosphorus such as red phosphorus, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, resorcinol bisphenyl phosphate, bisphenol A bisdiphenyl phosphate, and the like. Examples include acid esters and borate esters. One type of these flame retardants may be used, or two or more types may be used in combination.

  Examples of the mold release agent include silicon oil, stearic acid ester, carnauba wax and the like. One type of these release agents may be used, or two or more types may be used in combination.

  The fiber-reinforced composite material of the present invention is obtained by impregnating a fiber substrate with the resol type phenol resin composition of the present invention and curing it. As the fiber base material, for example, glass fiber, carbon fiber, aramid fiber, boron fiber, alumina fiber, silicon carbide fiber or the like is used, and two or more kinds of these fibers may be mixed and used. The form of the fiber base material is not particularly limited, and for example, long fibers aligned in one direction, tows, woven fabrics, mats, knits, braids, short fibers chopped to a length of less than 10 mm, and the like are used. . As used herein, long fibers refer to single fibers or fiber bundles that are substantially continuous by 10 mm or more. The short fiber is a fiber bundle cut to a length of less than 10 mm.

  The fiber-reinforced composite material of the present invention is usually obtained by impregnating a fiber substrate with the resol-type phenol resin composition of the present invention and then heating at 100 to 200 ° C. for 10 minutes to 12 hours. When curing, for example, curing may be performed at a high temperature such as 170 ° C., or curing may be performed at a relatively low temperature of 100 ° C. and then the temperature may be increased to be cured.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. In the examples, “part” and “%” are based on mass unless otherwise specified.

Synthesis Example 1 [Preparation of water-soluble resol type phenol resin (A)]
A 1000 ml four-necked flask equipped with a condenser was charged with 154 g of phenol, 213 g of a 42% formalin aqueous solution, and 105 g of a 48% potassium hydroxide aqueous solution, and heated and stirred for 2 hours in an oil bath at 70 ° C. for reaction. After dehydration under reduced pressure, the temperature was lowered to 50 ° C., and after the reaction, the mixture was adjusted with a 48% aqueous potassium hydroxide solution until pH 11.5 was obtained to obtain 400 g of a water-soluble resol type phenol resin (A1). The pH of the water-soluble resol type phenol resin (A1) was 11.4, and the nonvolatile content at 135 ° C. was 67%.

Synthesis example 2 (same as above)
Synthesis was performed in the same manner as in Synthesis Example 1 except that pH adjustment was not performed with a 48% aqueous potassium hydroxide solution after the reaction, to obtain 320 g of a water-soluble resol type phenol resin (A2). The water-soluble resol type phenol resin (A2) resin pH was 8.9, and the nonvolatile content at 135 ° C. was 73%.

Synthesis example 3 (same as above)
Synthesis was carried out in the same manner as in Synthesis Example 1 except that 115 g of phenol, 220 g of 42% formalin aqueous solution, 54 g of 49% sodium hydroxide aqueous solution, and 115 g of water were charged in the flask to obtain 480 g of water-soluble resol type phenol resin (A3). It was. The pH of the water-soluble resol type phenol resin (A3) was 11.5, and the nonvolatile content at 135 ° C. was 42%.

Synthesis Example 4 [Preparation of water-soluble resol type phenol resin (a) for comparison]
Synthesis was performed in the same manner as in Synthesis Example 1 except that the pH was adjusted to 6.2 with 98% sulfuric acid after the reaction to obtain 310 g of a comparative water-soluble resol type phenol resin (a1). The water-soluble resol type phenol resin (a1) resin pH was 6.2, and the nonvolatile content at 135 ° C. was 74%.

Example 1
A water-soluble resol-type phenol resin (A) and a water-soluble solvent (B) were blended according to the formulation shown in Table 1 to obtain a resol-type phenol resin composition (1) of the present invention. In addition to evaluating the curability of the resol type phenol resin composition (1), the appearance of the cured product, and the pot life, the fiber reinforced composite material is manufactured using the resol type phenol resin composition (1), and the bending characteristics are evaluated. went. The evaluation method is shown below. The evaluation results are shown in Table 1.

<Evaluation method of curability>
According to JIS K6910 5.14.2 gelation time B method, the gelation time of the resol type phenol resin composition at 150 ° C. was measured. The shorter this time, the better the curability.

<Method for evaluating appearance of cured product>
The test piece is dried with a constant temperature drier under two conditions (condition A: 110 ° C. × 5 minutes + 170 ° C. × 10 minutes, condition B: 170 ° C. × 10 minutes), and the occurrence of blistering on the appearance at the time of removal is visually observed, The case where there was no bulge in the appearance was marked with ◎, the bulge was confirmed but the diameter was smaller than 1 mm, and the case where there was at least one bulge with a diameter of 1 mm or more was marked as x.

<Evaluation method of pot life>
The resol type phenolic resin composition was charged into a 100 ml beaker and then stirred with a glass rod. The elapsed time until the time when the composition in the beaker became cloudy and lost transparency was measured and defined as the pot life. The longer this time, the better the pot life.

<Evaluation method of bending characteristics>
^Two 150 × 150 mm glass mats each having a weight of 300 g / m ² were placed on a glass plate, and the resol type phenol resin composition was applied to each glass mat with a roller so as to be 650 g / m ² . After drying the test piece with a constant temperature drier under two conditions (Condition A: 110 ° C. × 5 minutes + 170 ° C. × 10 minutes, Condition B: 170 ° C. × 10 minutes), the obtained cured product was bent according to JIS K7017 A method. Characteristics were measured.
In order to align curing conditions with those in which swelling occurred in the swelling test, the samples used for the bending test were cured at room temperature for 48 hours and then dried under the respective temperature conditions to prepare test pieces without swelling.

Examples 2-8 and Comparative Examples 1-6
Resol type phenolic resin compositions 2 to 8 and comparative resol type phenolic resin compositions 1 'to 6' were obtained in the same manner as in Example 1 except for the formulations shown in Tables 1 to 3. The same evaluation as in Example 1 is performed, and the evaluation results are shown in Tables 1 to 3.

Footnotes in Tables 1 to 3 (A1): Water-soluble resol type phenol resin (A1)
(A2): Water-soluble resol type phenol resin (A2)
(A3): Water-soluble resol type phenol resin (A3)
(A1): Water-soluble resol type phenolic resin for comparison (a1)
DEG: Diethylene glycol Additive A: Silane coupling agent “KBM-403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
Additive B: Silane coupling agent "KBM-602" (N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. Additive C: Silane cup manufactured by Shin-Etsu Chemical Co., Ltd. Ring agent "KBE-903" (3-aminopropyltriethoxysilane)
Acid curing agent: 65% paratrienesulfonic acid aqueous solution

Claims (5)

  A resol-type phenol resin composition comprising a water-soluble resol-type phenol resin (A), a water-soluble solvent (B) having a boiling point of 110 to 300 ° C., and water, and having a pH of 8 to 13.   The resol type phenol resin composition according to claim 1, wherein the resol type phenol resin (A) is an aqueous solution of a resol type phenol resin (A) having a resin solid content concentration of 60% or more.   The resol-type phenol resin composition according to claim 1, wherein the water-soluble solvent (B) is one or more water-soluble solvents selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol.   The resol type phenol resin composition according to any one of claims 1 to 3, wherein the content of the organic solvent (B) is 1 to 15 parts by mass with respect to 100 parts by mass of the water-soluble resol type phenol resin (A). .   A fiber-reinforced composite material obtained by impregnating a fiber substrate with the resol-type phenol resin composition according to any one of claims 1 to 4 and curing it.