JPH0347848A - Production of prepreg - Google Patents

Abstract

PURPOSE:To obtain a prepreg useful as a structural material for sporting goods, an aeroplane, etc., by impregnating a solution of an organic solvent containing a bis (oxazoline) compound, an epoxy compound, an aromatic amine compound and a curing catalyst into a fiber reinforcing material and then evaporating the solvent. CONSTITUTION:A solution of an organic solvent containing (A) a bis(2-oxazoline) compound [preferably 1,3-bis(oxazolin-2-yl) benzene], (B) an epoxy compound (preferably bisphenol A glycidyl, bisphenol diglycidyl, alicyclic epoxy compound) containing at least two epoxy groups in the molecule, (C) an aromatic amine compound (preferably 4,4'-methylenebisaniline) containing at least two amino groups in the molecule and (D) a curing catalyst (preferably aniline hydrodromide) is impregnated into a fiber reinforcing material and then the solvent is evaporated to give the objective prepreg.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel method for producing prepreg, which is used as a structural material for sporting goods, aircraft, industrial equipment, electrical equipment, and the like.

BACKGROUND OF THE INVENTION Conventionally, various prepregs have been made by impregnating a fiber reinforced material with a thermosetting resin.

Well-known resins used include phenol resin, epoxy resin, unsaturated polyester resin, thermosetting polyimide resin, and isocyanate bismaleimide (BT resin).

On the other hand, various thermosetting resins made from bis(2-oxazoline) compounds are known. For example, it is disclosed in the US patent that a thermosetting resin can be obtained by heating and reacting about 1 mole or more of a bis(2oxazoline) compound with a dicarboxylic acid in the presence of an organic phosphate catalyst. No. 3°476.712. Furthermore, it is also described in JP-A-62-104838 that a thermosetting resin can be obtained by heating and reacting a bis(2-oxazoline) compound and an aromatic diamine. Furthermore, one type of compound selected from the group consisting of bis(2-oxazoline) compounds, polyepoxy compounds, polyamine compounds, intramolecular acid anhydrides, and aromatic polyhydroxy compounds is heated under an acidic catalyst to generate heat. It was also disclosed in JP-A-64-26 that a curable resin can be obtained.
It is described in No. 628.

Moreover, a composite material of a thermosetting resin made from a bis(2-oxazoline) compound and a fiber reinforced material is recognized to have excellent heat resistance and high strength. It has also been reported that a prepreg is produced by dissolving a melt of a bis(2-oxazoline) compound and a polyhydric phenol compound in acetone and impregnating it with a fiber reinforcing material. but,
Bis(2-oxazoline) compound - Bis(2-oxazoline) compound - Aromatic diamine type and bis(2-oxazoline) compound - Aromatic Prepregs based on group diamine-epoxy compounds are completely unknown.

Problems to be Solved by the Invention The present inventors have conducted extensive research and discovered a method for producing a bis(2-oxazoline) compound-aromatic amine compound-epoxy compound based prepreg, and based on this knowledge, the present invention has been developed. I was able to complete it.

An object of the present invention is to provide a useful and novel prepreg by impregnating a fiber reinforced material with resin raw materials of a bis(2-oxazoline) compound, an aromatic amine compound, and an epoxy compound.

Means for Solving the Problems The method for producing prepreg according to the present invention comprises: (a) a bis(2-oxazoline) compound; (b) an epoxy compound having at least two epoxy groups in the molecule; A method for producing a prepreg, which comprises impregnating a fiber reinforcing material with an organic solvent solution containing an aromatic amine compound having at least two ami7 groups and (d) a curing catalyst, and then volatilizing the solvent. be.

Examples of the bis(2-oxazoline) compounds used in the present invention include compounds represented by the general formula (wherein R, and R2 each represent hydrogen or an alkyl group having 1 to 3 carbon atoms). It will be done. Specific examples of compounds represented by the general formula 2 include 1,3-bis(2-oxazolin-2-yl)benzene, 1,4-bis(2-oxazolin-2-yl)benzene, 1 ,3-bis(5methyl-2-oxazoline-2-
il) benzene.

Examples include 1,4-bis(5-methyl-2-oxazolin-2yl)benzene.

These bis(2-oxazoline) compounds may be used alone or in a mixture of two or more.

Further, as a bis(2-oxazoline) compound, a compound having, for example, an ester, carbonate, or ether bond in the main chain and having oxazoline rings at both ends can also be used. A compound having an oxazoline ring at both ends is, for example, compound 1 having a carboxyl group at both ends.
It can be obtained by reacting 2 mol or more, preferably 2 mol, of a bis(2oxazoline) compound at about 100 to 200°C.

Examples of compounds having carboxyl groups at both ends include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and oligomeric dicarboxylic acids having ester, carbonate, or ether bonds in the main chain. Specific examples of aliphatic dicarboxylic acids include adipic acid, sebacic acid, and dodecanedioic acid, and examples of aromatic dicarboxylic acids include terephthalic acid and naphthalene dicarboxylic acid. Oligomeric dicarboxylic acids include, for example, about 1 mol of an oligomeric diol such as polyester diol, polycarbonate diol, polyether diol, and 2 or more mol, preferably 2 mol, of an acid anhydride at about 100 to 200°C.
It is obtained by reacting for about 10 minutes to 2 hours. Examples of acid anhydrides include succinic anhydride, phthalic anhydride,
Examples include tetrahydrophthalic anhydride. The molecular weight of the oligomer diol used is within the range of about 300 to 3,000. If necessary, the bis(2-oxazoline) compound represented by the above general formula has, for example, an ester, carbonate, or ether bond in the main chain,
A mixture of compounds having oxazoline rings at both ends may be used.

Specifically, the epoxy compound having at least two epoxy groups in the molecule used in the present invention includes bisphenol-type epoxy compounds such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and tetrabromobisphenol A diglycidyl ether. compounds, diglycidyl phthalate, diglycidyl terephthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl p-oxybenzoate, diglycidyl dimamate, etc. Examples include ester type epoxy compounds, novolac type epoxy compounds, alicyclic epoxy compounds, and the like. these are,
Used alone or as a mixture.

Among the above-mentioned epoxy compounds, bisphenol A diglycidyl, bisphenol diglycidyl, and alicyclic epoxy compounds are preferred.

In the present invention, in addition to the above-mentioned epoxy compounds, monoepoxy compounds having one epoxy group in the molecule can also be used. Examples of such monoepoxy compounds include phenylglycidyl ether and allylglycidyl ether.

The aromatic amine compound having at least two amino groups in the molecule used in the present invention may be either a monocyclic or polycyclic compound, and specifically, for example,
0-lm- or p-phenylene diamine, 2,3- or 2,4- or 2,5-1-lylene diamine, 4.4'
-diaminobiphenyl, 3,3-dimethoxy-4,4°
-diaminobiphenyl, 4,4-diaminotriphenylmethane, 3°3'-dimethyl-4,4°-diaminobiphenyl, 2,2'-,5,5'-tetrachloro-4,4
'-diaminobiphenyl, 4,4'-methylenebisaniline, 4,4-methylenebis(2-chloroaniline),
To 2゜2゛-bis[4-(4-aminophenoxy)phenyl]propa 1,3-bis(4-aminophenoxy)
Benzene, 1,3-bis(3-aminophenoxy)benzene, 3.4'-diaminodiphenyl ether, 4.4
-diaminodiphenyl sulfone, 4,4 diaminodiphenyl sulfide, 4I4''-bis(aminophenyl)
Amine, 4,4'-[1,3-phenylenebis(1-methylethylidene)cobisaniline, trimethylenebis(
4-aminobenzoate), polytetramethylene oxide di-p-aminohenshade represented by the following formula, and the like.

These aromatic amine compounds may be used alone or as a mixture of two or more.

Among the above, in particular, 4,4°-methylenebisaniline, 4,4'-methylenebis(2-chloroaniline)
, 1.3-bis(4-aminophenoxy)benzene, 3
．． 4'-diaminodiphenyl ether 4.4'-diaminodiphenyl sulfide, 2.2bis[1-(4-aminophenoxy)phenyl J propane, etc. are preferred.

In the present invention, in addition to the above three components, polybasic acids having at least two carboxyl groups in the molecule and aromatic rings containing 7 amino groups and carboxyl groups are used for the purpose of increasing the solubility of Fes and adjusting the viscosity. Compounds (hereinafter sometimes referred to as additive compounds) may also be used.

Among the above additive compounds, polybasic acids include, for example, adipic acid, azelaic acid, sebacic acid, dodecanoic acid,
Examples include aliphatic dibasic acids such as timer acid and aromatic dibasic acids such as terephthalic acid and natutaledicarphonic acid.Specific examples of compounds having both an amine group and a carboxyl group in the aromatic ring For example, anthranilic acid p-aminobenzoic acid is used.These additive compounds can be used alone or as a mixture of two or more.

The blending ratio of the three components used in the present invention is bis(2
-oxazoline) compound, an aromatic amine compound, and an epoxy flower stand, the range satisfies the number of oxazoline rings+the number of epoxy groups≧the number of amino groups. Further, in this case, the epoxy compound is usually used in an amount of 1 epoxy group equivalent or less per 1 amino group equivalent of the aromatic amine compound.

In systems in which additive compounds are added to bis(2-oxazoline) compounds, aromatic amine compounds, and epoxy compounds, the ratio of raw materials used is the number of oxazoline rings + the number of epoxy groups ≧ the number of amino groups + the number of carboxyl groups. It is used within the range that satisfies the following.

In the present invention, the substrate (organic solvent solution) used to produce the prepreg is a bis(2-oxazoline) compound having at least two epoxy groups in two molecules, and at least two amino groups in one molecule of the epoxy compound. It is prepared by mixing an aromatic amine compound curing catalyst and an organic solvent. Specifically, a bis(2-oxazoline) compound, an aromatic amine compound, and an epoxy compound are heated and dissolved, and if necessary, the aromatic amine compound and the epoxy compound are reacted, and then a catalyst and a solvent are added. , or after heating and dissolving the aromatic amine compound and the epoxy compound in advance and reacting if necessary,
It is prepared by adding a bis(2-oxazoline) compound, a catalyst, and a solvent. At this time, the organic solvent used can uniformly dissolve the resin raw material,
Further, it is desirable that the solvent can be removed at a relatively low temperature from the fiber reinforced material to which the resin raw material is attached. Preferred solvents that satisfy these conditions include lower alcohols,
Examples include ethylene glycol monoalkyl ether or its acylate.

Examples of lower alcohols include methanol ethanol, isopropyl alcohol, and n-7'tanol; examples of ethylene glycol monoalkyl ethers include ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; and examples of acylates include ethylene glycol monoalkyl ether. Examples include acetate ester of ethyl ether. A lower alcohol may be added to the ethylene glycol monoalkyl ether. The mixing ratio of lower alcohol/ethylene glycol monoalkyl ether or its acylate is in the range of about 10/90 to 90/10 by weight. The solvent has a resin solid content ratio of about 20 to
An amount of 80% by weight is used, more preferably about 30-70% by weight. The melting temperature varies depending on the type and amount of individual resin raw materials, but in most cases it is between 50℃ and 180℃.
, preferably in the range of about 100' to 150°C, and for about 5 to 60 minutes. The time required for dissolution and reaction depends on the type and amount of raw materials and the heating temperature, but is about 5 minutes to 5 hours, preferably about 20 minutes to 1.5 hours.

The curing catalyst used in the present invention is preferably a catalyst that does not cause gelation during the preparation of the resin solution or during the drying process (also, the obtained prepreg is stable, and is capable of curing quickly during molding).

Such catalysts include, for example, compounds having an aliphatic hydrocarbon carbon to which a halogen element is bonded and hydrohalides of aromatic monoamines.

Preferred examples of compounds having an aliphatic hydrocarbon carbon to which a halogen element is bonded are monohaloalkanes and polyhaloalkanes, such as methyl iodide,
Butyl chloride, butyl bromide, butyl iodide, n-hexyl bromide, octyl chloride, n-octyl bromide, lauryl bromide, stear bromide, 1J nope allyl bromide, ethane tetrabromide, etc. Preferred examples include, for example, Hensyl bromide, p.

Examples include monohalomethylbenzene such as p'-dichloromethylbenzene, polyhalomethylbenzene, and halogenated fatty acid esters such as ethyl 2-bromopropionate and ethyl 2-bromoisobutyrate. Furthermore, cyclohexyl halides such as cyclohexyl chloride, cyclohexyl bromide, and cyclohexyl iodide can also be used.

Examples of hydrohalides of aromatic monoamines include alkylanilines such as aniline, methylaniline, and ethylaniline, hydrochlorides, hydrobromides, and iodine of aromatic monoamines such as toluidines, xylidines, and naphthylamines. Examples include hydrochloride.

The above catalysts may be used alone or in combination of two or more.

Among the above, particularly preferred are aniline hydrochloride, hydrobromide, ethyl 2-bromoisobutyrate, ethyl 2-bromopropionate, cyclohexyl bromide, and n-octyl chloride.

In the method of the present invention, these catalysts are added to the resin raw materials, i.e., the sum of the above-mentioned bis(2-oxazoline) compounds, epoxy compounds and aromatic amine compounds (including the amount of additive compounds, if used). A range of about 0.05 to 5% by weight is used, preferably a range of about 0.001 to 2% by weight.

In the present invention, a thickener such as Aerosil may be added to the varnish in order to adjust the fluidity of the prepreg. Furthermore, since the water content of the solvent may affect the curability, it is also useful to use a solvent with low water content or to add a dehydrating agent such as molecular sieve when preparing the varnish.

The fiber reinforcement material is impregnated with the varnish thus prepared.

Typical fiber reinforcement materials used in the present invention include glass fibers, carbon fibers, aromatic polyamide fibers, etc.; Any type of glass such as C-glass, A-glass and S-glass can be applied. Examples of carbon fibers include those manufactured using polyacrylonitrile fibers, cellulose fibers, pitch, aromatic hydrocarbons, carbon black, and the like as raw materials. Examples of aromatic polyamide fibers include poly-p-phenylenetetraphthalamide and poly-ruaminobenzamide.

These fiber reinforced materials can be classified into rovings, chopped strand mats, continuous mats, cloths, roving cloths, surfacing mats, and chopped strands depending on their shape. They are appropriately selected depending on the intended use and performance of the product, and two or more types or shapes may be used in combination if necessary.

The operation of impregnating the fiber reinforced material with varnish is carried out by dipping the fiber reinforced material into a container containing the varnish or by sprinkling the varnish onto the fiber reinforced material. This operation is carried out at room temperature or above. Solvent removal from the impregnated fiber reinforcement is accomplished by heating. The conditions are 50 to 200°C for 5 minutes to 1 hour.

The prepreg made in this way is cut into shapes according to the purpose, stacked, placed in a mold set in a press and sprayed with a mold release agent, and cured by applying temperature and pressure.
The desired fiber-reinforced molded product can be obtained. At this time, the temperature used is about 120-200°C, and the pressure is about 0.5-30 kg/cm", preferably about 0.
, 5~l Okg/am'.

Curing time is about 10 minutes to 2 hours, usually about 30 minutes to 1 hour.

Effects of the Invention According to the method of the present invention, a bis(2-oxazoline) compound, an aromatic amine compound, an epoxy compound, a curing catalyst,
By making prepreg varnish using organic solvent and soaking the fiber reinforcement material in it and pulling it up and drying it, it has good storage stability, is easy to handle, and can be cured and molded quickly without resin leakage. It is possible to obtain brevlegs that harden. The molded product is highly heat resistant, has high strength, and has great adhesion to the fiber reinforcing material, so it has high interlaminar shear strength and is extremely useful industrially.

Example The present invention will be explained below with reference to Examples.

Example 1 1.3-bis(2-oxazolin-2-yl)benzene 108,108 O mol), 4,4'-methylenebisaniline 792 g (4 mol), Epicron 860 (Dainippon Ink & Chemicals Co., Ltd.) 000 g (equivalent to 2 moles) was weighed, dissolved in an oil bath at 150°C, and 120 to 13
React at 0°C for 30 minutes.

Then a mixture of methanol and methylceasolve 1:I 5
Add I2 and dissolve. Cool this resin liquid to room temperature and
- A varnish was prepared by adding 57 g of ethyl bromoinbutyrate. The resulting varnish is a clear, low viscosity solution. 300
A woven fabric made by plain weaving yarns made of bundles of 0 carbon fiber filaments at a weaving density of 13 threads/inch was dipped in varnish at room temperature, and after impregnation, it was pulled up and dried at 100'C for 10 minutes to obtain a prepreg. This prepreg is stable even when left at room temperature, has appropriate toughness, and is easy to handle. Twelve sheets of this prepreg were laminated at 160℃ and 5 kg/am'
The mixture was cured for 1 hour under heat and pressure to obtain a composite material with a thickness of 2.5 mm.

The physical properties of the composite material were as follows.

Bending strength (kgf/+nm2) 103, 4 Bending strength (kgf/mm") 6050 Interlaminar shear strength (kgf/mm") 7.2 Example 2 1.3-Bis(2-oxazolin-2-yl) Weighed out 864 g (4 mol) of benzene and 202 g (1 mol) of sebacic acid, and heated them on a 150°C oil bath at an internal temperature of 140'C for 30 minutes.
The mixture was heated for 1 minute to cause a dissolution reaction and a clear liquid was obtained. Also, 4.4
'-Methylenebisaminoaniline 792g (4 mol) and Epicote 828 (manufactured by Yuka Shell Co., Ltd.) 370g (1
molar equivalent) was heated on an oil bath at 135°C for 40 minutes at an internal temperature of around 120°C to cause a dissolution reaction and obtain a transparent liquid. The respective liquids were mixed, cooled to 110°C, and a 4:6 mixture of isopropyl alcohol and cellosolve acetate 412 was added and dissolved uniformly. Ethyl 2-bromopropionate 3
3 g was added to obtain a transparent varnish. A plain weave glass cloth (WE-22D104BZ2 manufactured by Nitto Boseki Co., Ltd.) was applied at room temperature, pulled up and dried at 120°C for 15 minutes to obtain a prepreg. Laminated 14 sheets of this prepreg, 160°
It was cured for 1 hour under heat and pressure of C, 5 kg/cm' to obtain a composite material with a thickness of 3.0 mm.

The physical properties of the composite material were as follows.

Tensile strength (kgf/mm2) 42.3 Tensile modulus (kgJ/mm2) 940 Bending strength (kgf
/mm') 51, 8 Flexural modulus (kgf/m
m”) 2140 Compressive strength (kgf/mm”)
52,9 Example 3 1.3-bis(2-oxazolin-2-yl)benzene 864 g (4 mol), para-amino-7 benzoic acid 69 g (0,
5 moles), 820 g (2 moles) of 2,2"-bis[4-(4-aminophenoxy)phenyl]propane, polyether skeleton oligomer having an aromatic amine group at the molecular end (elasmer manufactured by Ihara Chemical Co., Ltd.) 1000) 123
0 g (equivalent to 1 mol) and Epicote 815 (Yuka Shell (
Co., Ltd.) 555g (1.5 mol) was weighed and heated to 140°C.
The mixture was dissolved and reacted in an oil bath for 1 hour. Next, 5Q, a 1=1 mixture of ethanol and ethyl cellosolve, was added, followed by 71 g of cyclohexyl bromide to obtain a transparent varnish. Cool to room temperature and carbon fiber roving (C manufactured by Kurashiki Boseki Co., Ltd.)
200CD) was immersed, pulled up and dried at 1100C for 10 minutes to obtain a prepreg. This prepreg is stable even when left at room temperature, has appropriate toughness, and is easy to handle.

Example 4 Preparation of varnish 4.264 g of 4'-diaminodiphenylmethane (1,3
3 mol) and 123 g (0.33 mol) of epoxy resin Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd.) were weighed in a heater, and 400 g of ethylene glycol monomethyl ether was added thereto and dissolved.

Next, 288 g (1,33 mol) of 2.2"-(1,3-phenylene)bis-2-oxazoline was weighed into another beaker, and 600 g of ethylene glycol monomethyl ether
g was added, and the mixture was placed in an oil bath and heated to 60'C to dissolve it.

Combine these two solutions and add about 2 ounces of calcium chloride to it.
0 g was added and stirred thoroughly to remove water in the solution. Then, 14 g of aniline hydrobromide and Aerosil #3
00 was added and stirred thoroughly to obtain a translucent, low viscosity varnish.

Preparation of Prepreg A woven fabric made by plain weaving carbon fibers made of bundles of 3,000 filaments at a weaving density of 13 filaments/inch was impregnated with the above varnish at room temperature, and left in an oven at 100°C for 910 minutes to dry. Got prepreg.

Lamination of prepreg and measurement of physical properties Twelve sheets of the prepreg described above were laminated, placed in a mold at 130°C, and clamped under a pressure of 5 kg/cm' for 1 hour to harden, resulting in a laminate of 2.5 mm thickness. Got the board. The strength of this laminate was measured and the following results were obtained.

Short beam interlaminar shear strength 3,7 kg/mm
23-point bending strength 4,4 kg/m
m23 point bending modulus 5650 kg/m
m' Example 5 Preparation of varnish The same procedure as in Example 4 was carried out.

Preparation of Prepreg Carbon fibers made of 12,000 filaments were impregnated with varnish and dried at 140°C for 40 seconds to obtain a yarn-like prepreg.

Lamination of prepreg and measurement of physical properties This prepreg has a width of 12.7 mm and a height of 2 mm.

34 pieces were set in a mold with a length of 250+ nm (temperature: 130°C), and the mold was closed for 1 hour by applying a pressure of 30 kg/cm'. The physical properties of the unidirectional composite material having a thickness of 2 mm thus obtained were measured and the following values were obtained.

Short beam interlaminar shear strength 10.8kg/mm
”3-point bending strength 175kg/mm2
3-point bending modulus II, 600kg/
mm'' Example 6 Preparation of varnish The same procedure as in Example 4 was carried out.

Preparation of Prepreg A unidirectional glass roving having a weight of 0.115 g per meter was impregnated with varnish and dried at 140° C. for 40 seconds to obtain a yarn-like prepreg.

Lamination of prepreg and measurement of physical properties This prepreg has a width of 12.7 mm and a height of 2 mm.

Set in a mold with a length of 250 mm (temperature 130°C),
The mold was closed and cured under a pressure of 30 kg/cm' for 1 hour to obtain a unidirectional composite material with a thickness of 1.9 mm. The physical properties of this material were measured and the following values were obtained.

Claims (4)

[Claims] (1) (a) bis(2-oxazoline) compound, (b) epoxy compound having at least two epoxy groups in the molecule, (c) aromatic amine compound having at least two amino groups in the molecule, and (d) A method for producing a prepreg, which comprises impregnating a fiber reinforcing material with an organic solvent solution containing a curing catalyst, and then volatilizing the solvent. (2) Claim (1) wherein the bis(2-oxazoline) compound is 1,3-bis(2-oxazolin-2-yl)benzene and the aromatic amine compound is 4,4'-methylenebisaniline. Prepreg manufacturing method. (3) The method for producing a prepreg according to claim (1), wherein the curing catalyst is aniline hydrobromide or 2-bromoisobutyric acid alkyl ester. (4) The method for producing a prepreg according to claim (1), wherein the organic solvent is ethylene glycol monoalkyl ether or its acylate.