JPH03106926A - New epoxy resin and its production - Google Patents

Abstract

NEW MATERIAL:An epoxy resin compound of the formula (wherein R is H or CH3; X is -CH2OH; m is 1-3; and n is 1-10). EXAMPLE:Glycidyl-etherified resol. USE:A molding material, a sealing agent for electronic components, a matrix resin for substrates and composite materials, an adhesive, a coating material, especially use in the production of FRP by filament winding. PREPARATION:Phenol(P) is reacted with formaldehyde(F) in a molar ratio (F/P) of 0.5-3.0 in the presence of a basic catalyst (in an amount to give a weight ratio to the phenol of 0.001-0.1) to form a resol, which is reacted with an epihalohydrin (in an amount desirably 1.5-7 times the number of moles of the hydroxyls of the starting resol) at 50-100 deg.C for 2-50hr in the presence of an alkali metal hydroxide (desirably in an amount substantially equimolar to the hydroxyls of the starting resol) to form a glycidyl ether, and the product is extracted with a solvent such as an aromatic hydrocarbon or a ketone to obtain a lowly viscous normally liquid epoxy resin of the formula.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a new epoxy resin and a method for producing the same. Since the epoxy resin according to the present invention provides a cured product with excellent heat resistance, water resistance, and mechanical properties, it can be used as a variety of molding materials, sealants and substrates for electronic components, matrix resins for composite materials, and even adhesives and coating materials. It has a wide range of uses such as [Conventional technology] In the FW method (filament winding method), a reinforcing fiber base material such as glass fiber or carbon fiber is impregnated with a thermosetting resin and wound around a mandrill, and after the resin is cured, the mandrel is pulled out (in some cases). (In some cases, the mandrill remains in the product as it is.)
(fiber-reinforced plastic).

According to the FW method, fibers can be arranged in any direction to impart properties such as strength and rigidity, so it is a method particularly suitable for manufacturing high-strength FRP. Thermosetting resins used in the FW method include phenol resins and epoxy resins. When manufacturing high-strength FRP, a low-viscosity liquid resin is used that can be well impregnated into the fiber base material. Resole, a type of thermosetting resin, is a soluble, fusible primary condensation product containing a large amount of methylol groups, obtained by reacting phenols and aldehydes in the presence of a basic catalyst. It's a bottom thing. When this is heated alone or in the presence of a small amount of catalyst, it crosslinks through dehydration, yielding an insoluble and infusible cured product (a phenolic resin called regit) with excellent heat resistance. Although this resol has been used to manufacture FRP with phenolic resin as the matrix resin, it has had the following problems. (2) The curing reaction of resol involves dehydration and also contains water as a diluent to lower the viscosity, so the cured product tends to foam due to water volatilization during curing.

In order to prevent foaming, strict temperature control and a sufficiently long curing time are required, which reduces work efficiency.

(2) In order to solve the above problems, expensive catalysts are used to shorten the curing time.

In this case, in addition to the cost of the catalyst, there is another problem in that the quality of the cured product deteriorates because the catalyst is incorporated into the cured product. (2) In manufacturing FRP, a low-viscosity liquid resin is desirable because it can be easily impregnated into the fiber base material. However, a large amount of unreacted phenol remains in low-viscosity resols, making it difficult to shorten the curing time. (2) On the other hand, if a high viscosity resol is used after its viscosity is lowered by heating, the curing reaction will be accelerated and the pot life for FRP production will become too short. On the other hand, if a solvent is used to lower the viscosity, the solvent must be removed during curing, making it impossible to shorten the curing time. As described above, the industrial production of FRP using resol resin is insufficient. On the other hand, epoxy resins have advantages such as short curing time compared to resols, and are widely used in various fields. Among epoxy resins, diglycidyl ether of bisphenol 8 is particularly widely used. However, because the resulting cured product has a low glass transition temperature, it cannot be used in fields where heat resistance is required. For fields that require heat resistance,
Multifunctional epoxy 4I made from phenol novolak, cresol novolak, etc.! A four-fatty compound, epoxy novolanc resin, is utilized.

Such epoxy novolak 4M resin has a large number of epoxy groups, so its heat resistance is improved, but its properties at room temperature are viscous liquid or solid. Therefore, in order to use it in the production of FRP, it was necessary to make it into a low-viscosity liquid by heating or diluting it with a solvent, but this causes the same problems as the above-mentioned resol. The recently developed epoxy resin made from polyhydric phenol is a liquid with low viscosity at room temperature, and is used in the production of FRP (Japanese Patent Publications No. 62-13352 and No. 62-56).
Publication No. 148). However, the glass transition temperature of a cured product of this epoxy resin is at most 240° C., and further improvement in heat resistance is desired. Moreover, this resin has 1,3.
Since the raw material is a special divalent or trivalent phenol such as 4-benzenetriol or dihydroxybenzenecarboxylic acid, the raw material is currently too expensive for mass production.

In addition, single resol compounds, i.e., p-cresol dialcohol, O-cresol dialcohol, and 0-cresol dinuclear dialcohol, were each reacted with shrimp chlorohydrin to convert phenolic hydroxyl groups into glycidyl ethers. Epoxy resin compounds are described in Kiichi Hasegawa et al., Proceedings of the Thermosetting Resin Symposium (1988), p.
121. However, the epoxy resin compounds obtained here are all crystals or viscous liquids at room temperature, and are not suitable for manufacturing FRP. Also,
The glass transition temperature of a cured product of this epoxy resin is at most 170°C, and its heat resistance is also insufficient. [Problems to be Solved by the Invention] The present invention provides an epoxy resin compound that can solve the contradictory properties (heat resistance, fluidity, curing properties) of the above-mentioned epoxy resins and phenol resins all at once. The purpose is to develop. [Means for Solving the Problems] The present inventors have succeeded in obtaining a novel epoxy resin that can achieve the above objectives by converting resol into glycidyl ether by reaction with epihalohydrin. Here, the gist of the present invention is to recover a resol obtained by reacting a phenol compound and an aldehyde in the presence of a basic catalyst from a reaction product obtained by reacting it with epihalohydrin in the presence of an alkali metal hydroxide. In addition, it is an epoxy resin that is a low viscosity liquid at room temperature.

This epoxy resin is produced by, for example, reacting a phenol compound and an aldehyde in the presence of a basic catalyst to produce a resol, which is then reacted with epihalohydrin in the presence of an alkali metal hydroxide to form a glycidyl ether.
It can be produced by recovering a solvent-soluble resin from this reaction product. However, other manufacturing methods can also be used as long as the desired epoxy resin that is a low viscosity liquid at room temperature can be obtained.

The present invention also provides a composite molding material using this epoxy resin and a method for manufacturing FRP using the FW method. Furthermore, the glycidyl etherified raw bottom material contained in the epoxy resin of the present invention produced using a resol obtained from phenol and formaldehyde as a starting material is a new compound. The present invention will be explained in detail below. The low-viscosity liquid epoxy resin of the present invention is obtained by reacting a resol obtained by condensing phenols and aldehydes in the presence of a basic catalyst with epihalohydrin. Next, a method for producing resol will be briefly explained.

As raw material phenols, compounds having at least one phenolic hydroxyl group such as phenol, cresol, xylenol, ethylphenol, phenylphenol, catechol, resorcinol, hydroquinone, and naphthol can be used. The following explanation uses phenol as a representative of phenols. Examples of aldehydes that serve as crosslinking agents include aliphatic or aromatic aldehydes such as formaldehyde, acetaldehyde, benzaldehyde, trioxane, hydroxybenzaldehyde, and glyoxal, or trioxane;
Aldehyde generating substances such as rose formaldehyde can be used alone or in combination of two or more. In the following, formaldehyde will be used as a representative example of aldehydes. As formaldehyde, formalin, which is an aqueous solution thereof, can also be used. Examples of basic catalysts include sodium hydroxide, barium hydroxide, magnesium hydroxide, lithium hydroxide, strontium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, amines (e.g. triethylane), ammonia, etc. Various alkaline or amine catalysts can be used.

There is no particular restriction on the type of catalyst, but since an alkali metal hydroxide is used in the subsequent glycidyl etherification step, it is preferable from a process standpoint to use an alkali metal hydroxide also in the resol aggregation step. In general, the synthesis reaction of resols involves a methylolation reaction in which formaldehyde is added to the hydrogen atom on the aromatic ring to form a methylol group, and a crosslinking process through dehydration condensation between the methylol group and the hydrogen atom on the aromatic ring. The condensation reaction proceeds sequentially. In order to obtain the low viscosity liquid epoxy resin of the present invention in high yield,
In the resol coalescence reaction, it is preferable to control the reaction so that it proceeds as homogeneously as possible while suppressing excessive condensation, leaving some unreacted phenol compounds, and producing a resol with a relatively low molecular weight. Therefore, although the resol synthesis reaction is possible without a solvent, it is preferable to carry out the reaction in a solvent because it becomes difficult to control the reaction. More preferably, the reaction is carried out under refluxing conditions of the solvent. Under solvent reflux conditions, the heat of reaction can be efficiently removed, the reaction temperature can be easily controlled, and excessive local condensation reactions can be prevented. Also,
In order to promote the condensation reaction, the water produced by the condensation may be removed from the reaction system simultaneously with the reflux of the solvent.

The reaction solvent used during resol synthesis is preferably a polar solvent that can dissolve any of the reactants and catalysts used as well as the resol product. More preferred polar solvents are liquid compounds capable of hydrogen bonding with phenolic hydroxyl groups, such as water, alcohols, and ketones. When such a polar solvent is used, the phenomenon in which phenols aggregate and become polymerized due to hydrogen bonds between phenolic hydroxyl groups can be prevented because the polar solvent forms hydrogen bonds with the phenols. Therefore, the phenols are uniformly distributed in the solvent, and local excessive condensation reaction can be prevented from proceeding.

One or more solvents can be selected as appropriate in consideration of the reaction conditions, but it is preferable to use a solvent with a relatively low boiling point so that the solvent can be easily removed by distillation after the reaction. preferable.

The reaction conditions are not particularly limited and are appropriately determined depending on the properties of the desired resol raw bottom material. Next, we will explain the conditions for a typical resol aggregation reaction. The molar ratio of phenol (P) and formaldehyde (F) is F/P = 0.5 to 3.
．． If the F/P molar ratio is less than 0.5, a low viscosity resin can be obtained, but the cured product may have a low glass transition temperature and insufficient heat resistance.

On the other hand, if this molar ratio exceeds 3.0, the yield of the obtained liquid resin tends to decrease.

The amount of solvent used is appropriately determined depending on the type of solvent used. For example, when using a polar solvent, which is a preferred solvent, the amount used is preferably within the range of 0.8 to 4.0 in terms of weight ratio to the raw material phenol. When using formalin, the polar solvent is already about 63% in the formalin.
Therefore, the amount of the polar solvent to be added separately is preferably within the range of about 0.1 to 3.0 in terms of weight ratio to the phenol. If the amount of solvent used is too small, the objective of controlling the condensation reaction may be difficult to achieve, and if the amount of solvent is too large, the reaction efficiency tends to decrease. The amount of catalyst used is 0.001 to 0.000% by weight relative to the raw material phenol.
It is preferably within the range of 1. Catalyst/phenol weight ratio is 0
．． If it is less than 001, the methylolation reaction may not proceed sufficiently, and the resulting cured product may have insufficient heat resistance. On the other hand, if this weight ratio exceeds 0.1, the yield of the desired liquid resin tends to decrease. This resol coalescence reaction is preferably carried out at a reaction temperature of 70 to 130°C and a reaction time of 10 minutes to 10 hours.
Although the reaction pressure is not particularly limited, it is usually carried out at normal pressure. However, if necessary, for example, increased pressure or reduced pressure may be employed to reflux the solvent at the reaction temperature.

After completion of this resol synthesis reaction, the used reaction solvent is removed to isolate the resol resin. Since the condensation reaction of resols progresses when heated, in order to prevent excessive condensation reactions, it is preferable to remove the solvent by distillation under reduced pressure. The degree of pressure reduction is not particularly limited, but in order to prevent condensation reactions, it is preferable to keep the pressure as low as possible and the distillation temperature.

Furthermore, when a basic catalyst other than an alkali metal hydroxide is used, this catalyst is removed from the resol by appropriate means such as washing with water. The resol resin obtained by the resol coalescence reaction may be one in which phenol has completely reacted, or one containing unreacted phenol. The degree of polymerization of the obtained resol and the amount of unreacted phenol contained therein are not particularly limited, but in order to obtain the low viscosity liquid epoxy resin of the present invention in high yield, the degree of polymerization of the resol must be relatively low. It is preferable that the amount of unreacted phenol is smaller, and the degree of polymerization of the resol is preferably lower.

However, since the viscosity of the resin is reduced by the subsequent glycidyl etherification, the raw material of the resol synthesis reaction may become a viscous liquid. Unreacted phenol can be present in a content within a wide range from a few percent or less to as much as about 50 percent by weight of the resol. If necessary, phenol can be added to the produced resol to adjust its content. Using a resol resin from which the polar solvent has been removed as a starting material, this is reacted with epihalohydrin in the presence of an alkali metal hydroxide by a conventional method to glycidyl etherify some or all of the phenolic hydroxyl groups in the resol compound, Develop a new low-viscosity liquid epoxy resin for the purpose. During this reaction with epihalohydrin, it is thought that some dehydration condensation of methylol groups and polymerization of glycidyl etherification products occur as side reactions, and the products can be obtained from various resin compounds containing methylol groups and/or epoxy groups. It seems to be a mixture.

However, it is thought that glycidyl etherification of the methylol groups in the resol hardly occurs. Furthermore, when the raw material resol contains unreacted phenol, this phenol is also converted into glycidyl ether and is included in the final epoxy resin compound. As the epihalohydrin, shrimp chlorohydrin, shrimp chlorohydrin, β-methyl shrimp chlorohydrin, etc. can be used. The amount of epihalohydrin used is 0.5 to 15 moles, preferably 1.5 to 7 moles, relative to the hydroxyl groups in the raw material resol. As the alkali metal hydroxide, sodium hydroxide, potassium hydroxide, etc. can be used. The amount of alkali metal hydroxide used is 0.5 to 0.5 to hydroxyl groups in the raw material resol.
Suitable amounts are 1.5 moles, preferably 0.8 to 1.2 moles, particularly preferably approximately equimolar amounts. As described above, since the amount of catalyst used is larger than that in the resol coalescence stage, it is necessary to add a catalyst even when an alkali metal hydroxide catalyst is used in the resol coalescence stage. It is preferable that the alkali metal hydroxide is added dropwise little by little in the form of a concentrated aqueous solution to the reaction system. If a large amount is added at once, local condensation reactions tend to occur. This glycidyl etherification reaction is carried out at 40-150'C without the presence of an organic solvent.
, preferably at a temperature range of 50 to 100°C for 2 to 50 hours.

It is preferable to carry out the reaction while removing water by-product from the reaction from the reaction system by azeotroping with the epihalohydrin, and in order to prevent condensation reactions, the reaction is carried out under reduced pressure.
It is preferable to lower the azeotropic temperature. After completion of the glycidyl etherification reaction, the epoxy resin product is recovered from the reaction mixture. Recovery of resin can be done, for example, by
This can be carried out by recovering epihalohydrin from a resin solution by distillation, and then separating the solvent-soluble epoxy resin of the present invention from the alkali metal salt and solvent-insoluble resin by solvent extraction. The solvent used for this solvent extraction is preferably an aromatic hydrocarbon solvent such as benzene, toluene, or xylene, or a ketone solvent such as a7tone, methyl ethyl ketone, or methyl isobutyl ketone. The amount of solvent used is not particularly limited as long as it is sufficient to extract the low viscosity liquid epoxy resin. The desired low-viscosity liquid epoxy resin can be isolated by separating the solvent from the obtained extract by distillation. When resol is synthesized from phenol and formaldehyde, the average resin content of the low viscosity liquid epoxy resin of the present invention consists of a resole glycidyl ether compound represented by the following formula.

R Xm In the formula, R is H or CH, X is -CH. OH, m is an integer from 1 to 3, and n means an integer of 1 to 10, respectively.

This epoxy resin compound is a new compound. In addition to this, the epoxy resin of the present invention includes a crosslinked product in which the epoxy compound represented by the above general formula (1) is crosslinked by condensation of methylol groups, a polymer in which epoxy groups undergo ring-opening polymerization, and glycidyl ether of phenol. Contains etc. While the aforementioned conventional epoxy resins derived from single resol compounds are solid or viscous liquid at room temperature, the novel epoxy resin of the present invention can be obtained as a liquid resin with low viscosity at room temperature. This is presumably because the epoxy resin of the present invention is a mixture of various components having a relatively low degree of polymerization, including the above-mentioned resole glycidyl ether compound. Furthermore, when the raw material resol contains unreacted phenol, the glycidyl ether of phenol contained in a small amount in the epoxy resin acts as a reactive diluent and effectively lowers the viscosity. As mentioned above, if a product with a relatively low degree of polymerization is obtained in the resol synthesis step, and if the reaction is controlled so that a small amount of unreacted phenol remains, a low viscosity product that is recovered as a solvent-soluble component after solvent extraction can be obtained. The yield of liquid epoxy resin increases. The low-viscosity liquid epoxy resin of the present invention can be cured by similarly using a conventionally used epoxy curing agent. Specific examples of usable curing agents include amine curing agents, polyaminoamide curing agents, acid and acid anhydride curing agents, and the like. Among these curing agents, aromatic amine curing agents are particularly preferred because the resulting cured product has a high glass transition temperature and provides a cured product with excellent heat resistance. The amount of curing agent used may be the same as that of conventional epoxy resins based on the epoxy equivalent of the epoxy resin. It is believed that the curing of the epoxy resin of the present invention proceeds through the involvement of ring-opening polymerization of epoxy groups and dehydration condensation of methylol groups. Conventional curing of resols has had the problem of foaming due to water as mentioned above, but no foaming is observed in the cured product of the epoxy resin of the present invention. This is because the resin of the present invention does not contain water, and during curing, a significant amount of epoxy curing agent is used, and this curing agent also has a catalytic action to promote dehydration condensation of methylol groups. This suggests that the methylol group undergoes dehydration condensation at the beginning of the curing reaction. Since the epoxy resin of the present invention is in a liquid state with low viscosity, it has excellent shapeability. Furthermore, the cured product of the epoxy resin of the present invention has excellent heat resistance, water resistance, and mechanical properties.

This Evokin resin can be used alone for coating, adhesive, various types of applications, or as a sealing or substrate material for electronic components. Furthermore, by taking advantage of its low viscosity liquid properties, it can be advantageously used as a matrix resin for composite materials.For example, it can be used as a matrix resin for composite materials.
Suitable for manufacturing RP. In particular, the FW method
It is suitable as a matrix resin when producing P.

Other epoxy resins may be mixed and used within a range that does not impair the useful properties of the epoxy resin of the present invention.

[Example] Examples according to the present invention will be shown below to specifically illustrate the present invention.

Example 1 (Synthesis of resol) Capacity 5 equipped with a stirring device, thermometer, nitrogen introduction tube, and reflux tube
1000 g of phenol, 37% in a 4-lof flask
Formalin aqueous solution 1295 g, methanol 1000 g
g, and 80 g of a 25% aqueous sodium hydroxide solution were charged, and the temperature was started to rise while stirring, and the reaction was carried out at 80°C for 4 hours. The formaldehyde/phenol molar ratio in this reaction is 1.5, and all polar solvents (methanol + water), including those derived from formalin and catalysts,
The weight ratio of phenol is I. 8. The weight ratio of methanol/phenol added was 1.0, and the weight ratio of catalyst/phenol was 0.02.

Methanol and water were distilled off under reduced pressure from the obtained resol solution using an evaporator, and a viscous resol of approximately 1,400 g
I got g. Infrared spectrum of the obtained resol and '
The H-NMR spectra are shown in Figures 1 and 2, respectively. The content of unreacted phenol contained in this resol was about 14% by weight, and the hydroxyl equivalent measured by the acetyl chloride method was about 72 g/mol. Note that unreacted formaldehyde was not detected.

(Glycidyl etherification of resol) Stirrer, thermometer, nitrogen inlet pipe, dropping funnel, and equipment for condensing and separating the azeotrope of shrimp chlorohydrin and water and returning the lower shrimp chlorohydrin to the reactor. In a 5-bottle flask with a capacity of 5 liters equipped with an apparatus, resol 13 obtained above was added.
60 g, and 2550 g of shrimp chlorohydrin (
approximately 1.5 mol) based on the hydroxyl group in the resol,
The temperature was started to increase while stirring, and the pressure was adjusted so that the azeotrope was distilled out at 75°C. Under these reaction conditions, 40% by weight aqueous sodium hydroxide solution 1
Dropping of 970 g (approximately 1.0 mol based on the hydroxyl group in the resol) was started and continued over 3.5 hours.

During this time, the azeotropic mixture of distilled shrimp chlorohydrin and water was condensed and separated, and the lower shrimp chlorohydrin layer was returned to the reactor. After completing the dropwise addition of the aqueous sodium hydroxide solution, the above reaction conditions were maintained for an additional 30 minutes to completely remove water from the reaction system. Next, shrimp chlorohydrin was distilled off under reduced pressure using an evaporator. 22% of toluene and 52% of acetone are added to the remaining reaction raw material.
were added sequentially to dissolve the resin at room temperature, and filtered. Toluene and acetone are distilled off from the filtrate using an evaporator to obtain a solvent-soluble low-viscosity liquid epoxy resin of the present invention.
800 g was collected.

On the other hand, the solvent-insoluble matter separated by filtration was washed with water to remove water-soluble alkali metal salts and unreacted alkalis, and about 800 g of solid reaction residue was obtained.

The infrared spectrum and 'lI-NMR spectrum of the epoxy resin of the present invention obtained from the filtrate are shown in Figures 3 and 4, respectively. Comparing the infrared spectra in FIG. 1 and FIG. 3, in FIG. 1 an absorption band specific to the methylol group is seen near IOIOCII-'. In contrast, in Figure 3, 800 to 92
Absorption specific to epoxy groups is observed near 0CIIl-1 and 1240 cm-', and absorption of methylol group is observed near 1010 cm-'.

When comparing the 'II-NMR spectra in Figure 2 and Figure 4, it is found that in Figure 4 after glycidyl etherification, δ-
An epoxy group peak is seen at 2.8 to 4.2 ppm. Furthermore, in both FIGS. 2 and 4, peaks of aromatic ring-bonded methylene and methylol groups are seen at δ=4 to 5 ppm.

From the above, the structure of the above formula (r) was assigned as a component contained in the epoxy resin in the present invention. In addition, when the molecular weight distribution of the liquid epoxy resin obtained above was measured by gel permeation chromatography (GPC), it was found that the glycidyl ether of phenol and the epoxy compound corresponding to n = 1 in the above formula (I), respectively. Two peaks that were considered to correspond were clearly observed. The peaks of substances with higher molecular weights overlapped with each other, but a considerable amount of such epoxy compounds with n=2 or more were also present. The number average molecular weight of the resin determined from the molecular weight distribution by GPC was 220. The epoxy equivalent of this epoxy resin was measured by the hydrochloric acid monodioxane method, and was found to be about 235 g/mol, and the hydroxyl equivalent, measured by the acetyl chloride method, was about 102 g/mol. The viscosity of this liquid epoxy resin is 800 at 20°C.
It was 0 cp. From these measurement results, as shown in Table 1 below, the average structure of the epoxy resin obtained in this example is as follows:
A structure represented by the following formula (II) can be considered. However, as mentioned above, the product is a mixture of various substances, so the structure below merely shows the average structure, and does not mean that this structure is the main precept. ．． Table 1 (Curing of epoxy resin) Ancamine, a commercially available aromatic amine curing agent, was mixed in an amount of 20% phr to the liquid epoxy resin obtained above, placed in a mold, and cured at 190°C for 3 hours. I let it happen. When the glass transition temperature of the obtained cured product was measured by TMA method, it was found to be 25
The temperature was over 0℃. [Comparative Example] Ancamine 23% phr was mixed with DER330 (manufactured by Dowke ξCal), a commercially available bisphenol A glycidyl ether type epoxy resin, and cured under the same curing conditions as in the above example. The glass transition temperature of the obtained cured product was 175°C. [Effects of the Invention] Although the novel epoxy resin of the present invention is a liquid resin with low viscosity at room temperature, it can be cured in the same curing time as conventional epoxy resins, and has excellent heat resistance. It is possible to judge the shape of the cured product. Moreover, the water resistance and mechanical properties of the cured product are also good.

Therefore, the epoxy resin derived from the resol of the present invention has excellent moldability, can be cured in a shorter time than conventional resols, and does not have the problem of foaming, so it has excellent workability.

Furthermore, the cured product of this epoxy resin has a glass transition temperature that is dramatically improved compared to conventional epoxy resins.
Shows high heat resistance comparable to resol.

Due to these characteristics, the low-viscosity liquid epoxy resin of the present invention can be used in a wide range of applications such as various prettier materials, sealants and substrates for electronic components, matrix resins for composite materials, as well as adhesives and coating materials. In particular, the production of FRP,
Among these, it is suitable for manufacturing FRP by the FW method.

[Brief explanation of drawings]

Figures 1 and 2 show infrared spectra and I-NMR spectra, respectively, of resols (starting materials for liquid epoxy resins of the present invention) obtained in Examples, and

Claims (5)

[Claims] (1) Low viscosity at room temperature, recovered from the reaction product obtained by reacting a resol obtained by reacting a phenol compound and an aldehyde in the presence of a basic catalyst with epihalohydrin in the presence of an alkali metal hydroxide. Liquid epoxy resin. (2) A phenol compound and an aldehyde are reacted in the presence of a basic catalyst to produce a resol, which is then reacted with epihalohydrin in the presence of an alkali metal hydroxide to form a glycidyl ether, and the reaction product is converted into a glycidyl ether. A method for producing an epoxy resin that is liquid at room temperature and has a low viscosity, which involves recovering a solvent-soluble resin. (3) A molding material containing the epoxy resin according to claim 1 and reinforcing fibers. (4) A method of manufacturing fiber-reinforced plastic products by a filament winding method using the epoxy resin according to claim 1. (5) A novel epoxy resin compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) In the formula, R means H or CH_3, X means -CH_2OH, m means an integer from 1 to 3, and n means an integer from 1 to 10, respectively.