JPH06173170A - Sizing agent composition for reinforcing fiber - Google Patents

Abstract

PURPOSE:To obtain the subject aqueous sizing agent composition containing a specific modified epoxy resin and a water-soluble penetrant as essential components and uniformly penetrable to the inner part of a hydrophobic reinforcing fiber. CONSTITUTION:This sizing agent is produced by compounding (A) a water-soluble and/or self-emulsifiable modified epoxy resin such as polyether adduct of an epoxy resin, epoxidized product of the adduct or epoxidized polyether derivative of a dihydroxy compound with (B) 0.05-5wt.% (based on the resin) of a penetrant composed of a water-soluble fluorinated alkyl compound and/or a water-soluble polysiloxane. The surface tension of the compounded composition is <=40dyne/cm at 20 deg.C at a concentration of 1wt.%. In the case of self- emulsifiable modified epoxy resin, the emulsion has a particle diameter of <=0.5mum and is free from particles of >=3mum diameter. Reinforcing fiber for composite material such as carbon fiber and aramid fiber can be uniformly sized with the sizing agent to the inner part of the fiber to increase the collectability and improve the adhesivity to the matrix resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sizing agent composition used for reinforcing fibers for composite materials such as carbon fibers, aramid fibers, aromatic polyester fibers, glass fibers and alumina fibers.

[0002]

2. Description of the Related Art Reinforcing fibers such as carbon fibers and aramid fibers used for composite materials are generally multifilaments or tow-shaped ones composed of an aggregate of several hundred or more thin single fibers. It is used as a sheet-like processed product aligned in the direction, a woven fabric, or a tow for filament winding. In these processing steps, a sizing agent is added in the step of manufacturing the fiber bundle or in the step before processing as a composite material in order to prevent the reinforcing fiber bundle from being wrapped around the fluffing roller and facilitate handling.

Many proposals have been made as sizing agents for reinforcing fibers. As a sizing agent used for this purpose, a water-soluble polymer or an epoxy resin is often used. These sizing agents are often acetone,
It is dissolved in an organic solvent such as Perclen or is used as an aqueous emulsion.

However, when an organic solvent is used, special consideration is required in terms of work environment and safety. From this point, it is advantageous to use it as an aqueous solution or an aqueous dispersion or emulsion (emulsion), but since the reinforcing fiber is usually hydrophobic, the sizing agent is evenly applied even within the reinforcing fiber bundle in a short time. It was difficult to get him to do it.

For example, Japanese Patent Publication No. 62-11112 proposes an emulsion-type sizing agent composed of a thermosetting resin or a thermoplastic resin containing a surfactant.

On the other hand, with these sizing agents, the particle diameter of the emulsion and the surface tension of the solution are not appropriate. Therefore, in the case of a thick fiber bundle composed of several thousand or more single fibers, the fiber bundle can be shortened in a short time. It cannot be said that the sizing agent is evenly applied to the inside of the composition.

Therefore, the carbon fiber bundle obtained by using them has a drawback that, in the pre-process of producing the unidirectional prepreg, when the fiber bundle is widely spread, the portion where the sizing agent is not adhered is fluffed. It is difficult to obtain high quality prepreg.

In order to solve these drawbacks, it is necessary to improve the composition of the sizing agent and the physicochemical properties of its aqueous solution. That is, a measure for improving the size of emulsion particles and the permeability of a solution is required, but no specific proposal satisfying this has been made yet.

[0009]

The present inventors have developed a water-soluble epoxy resin, a method for reducing the particle size of an aqueous emulsion, a method for lowering the surface tension of an aqueous solution, and the like in order to improve such drawbacks. As a result of extensive studies, the present invention has been reached.

That is, an object of the present invention is to provide a sizing agent composition capable of easily sizing fibers located inside a reinforcing fiber bundle composed of an assembly of a large number of single fibers.

More specifically, the sizing agent should be applied uniformly to the inside of the hydrophobic reinforcing fiber bundle in a short time without using a solvent that is flammable or harmful to the human body and to the extent that it does not pose a practical problem. Another object of the present invention is to provide a sizing agent composition capable of performing suitable sizing that can be performed and that does not hinder the adhesiveness between the reinforcing fiber and the matrix resin.

[0012]

The above-mentioned object of the present invention is to provide a water-soluble or self-emulsifying epoxy resin modified product, a water-soluble fluorinated alkyl compound, and / or
Alternatively, a penetrant composed of a water-soluble polysiloxane compound is used as an essential component, and the penetrant is added to the epoxy resin in an amount of 0.0
A sizing agent composition containing 5 to 5.0% by weight, wherein the surface tension of a 1% by weight aqueous solution of the sizing agent composition is 40 dyne / cm or less at 20 ° C.,
In addition, in the epoxy resin modified body having self-emulsifying property with respect to water, the average particle size of the emulsion in the aqueous solution is 0.5 micron or less, and the reinforcing fiber sizing does not contain particles of 3 micron or more. Effectively achieved by the agent composition.

The present invention will be described in detail below, but the terms used in the text will be explained in advance.

The sizing agent composition in the present invention is
As will be described later, it refers to a mixture of a modified epoxy resin, a penetrating agent, an emulsion stabilizer, and an improving agent for improving the smoothness and sizing property of reinforcing fibers.

The sizing agent or the aqueous solution of the sizing agent composition is a solution in which the sizing agent composition is dissolved or emulsified in an aqueous medium for application in the actual process.

The term "aqueous solution" does not necessarily mean only a single solution of water, but it should be treated with water within a range in which work environment and safety are taken into consideration and the effect of the sizing agent composition can be sufficiently exhibited. It refers to a solution that is dissolved or emulsified in a mixed solvent of a soluble organic solvent and water.

Examples of the organic solvent which can be mixed and used include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol and isoprolol alcohol, polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin, acetone, methyl ethyl ketone and diethyl. Examples thereof include ketones such as ketones, dioxane, methyl cellosolve, and the like.

The mixing ratio of these organic solvents and water varies depending on the type of organic solvent, but at least 5
It should be contained in an amount of 0% by weight or more, preferably 70% by weight or more.

Sizing refers to the operation of applying the sizing agent to the reinforcing fibers.

The water-soluble or self-emulsifying epoxy resin modified product, which is the main component of the sizing agent composition of the present invention, includes ethylene oxide (hereinafter abbreviated as EO) or propylene oxide as an epoxy resin. (Hereinafter P
Abbreviated as O), a polyether compound obtained by reacting a polyether compound such as O) or an epoxy compound obtained by further reacting an epoxy resin polyether compound with epichlorhydrin, or bisphenol, diphenol, dihydroxybenzene, dihydroxyanthracene, etc. Compounds obtained by epoxidizing the polyether derivative of the dihydroxy compound are preferably used, but are not limited thereto.

Although the bisphenol type is generally used as the epoxy resin, other phenol novolac type epoxy resins and alicyclic epoxy resins such as cyclohexylphenol can also be preferably used.

Although it is not easy to write modified compounds of these epoxy resins by the general formula, the general formulas are shown by taking bisphenol type epoxy resins and dihydroxy compounds as examples, and the following formulas (1), (2) and (3 ) Is written.

[0023]

[Chemical 1]

In the above formula, R and R'independently represent an alkyl group having 4 or less carbon atoms, l represents 0 or an integer of 1 to 5, and X and X'independently represent --CH ₂ --CH.
(OH)-CH _2- (EO) _n1 (PO) _m1 --H or --CH ₂ --CH (OH)-CH
_{2 - (EO) n2 (PO} ) represents _{m2 -N (CH 2 OH) 2} , EO represents ethylene oxide, PO represents propylene oxide, n1 represents an integer of 3 to 50, m1 is 0 or 1 Represents an integer of 100, n2 represents 0 or an integer of 1 to 50, and m2 represents 0 or an integer of 1 to 100.

[0025]

[Chemical 2]

Where R, R ', n1, n2, m1, m2,
EO, PO and l are as described above, and Y represents hydrogen or a glycidyl group.

[0027]

[Chemical 3]

In the formula, Ph represents a divalent aromatic or alicyclic group having two hydroxyl groups in the molecule, such as bisphenol, diphenol, dihydroxybenzene, dihydroxycyclohexane, dihydroxynaphthalene and dihydroxyanthracene, and n1, n2 , M1, m2, EO and PO are as described above, and Z represents hydrogen, a glycidyl group or —CH ₂ —CH (OH) —CH ₂ —N (C ₂ H ₄ OH) ₂ .

The modified hydrophilic epoxy resin represented by the general formulas (1), (2), (3), etc. is a homopolymer of ethylene oxide in which the polyether introduced to increase the hydrophilicity of the epoxy resin. (Degree of polymerization: 4 to 100), or a block or random copolymer with propylene oxide. Epoxy compounds having 0 to 2 epoxy rings in one molecule are preferable, and those having 3 or more epoxy rings in one molecule even after being converted into a hydrophilic modified epoxy resin are used as sizing agents. Gelling tends to occur and is not suitable for use.

Whether the modified epoxy resin is water-soluble or self-emulsifying depends on the number of moles of EO or PO added to improve hydrophilicity and the chemical structure of the epoxy resin. Although it is difficult to determine it, many of them are self-emulsifying when the number of moles of EO or PO added is 4 to 8, and water-soluble when the number of moles of EO or PO is 9 or more.

In the present invention which uses a water-soluble or self-emulsifying epoxy resin modified product, particularly an emulsifier for emulsifying the epoxy resin and an emulsifying agent for keeping the resulting emulsion particles (emulsion particles) stable. A stabilizer (emulsion stabilizer) is not required, but a small amount of emulsifier or emulsion stabilizer may be added. However, as described below, a 1% by weight aqueous solution of the sizing agent composition is at 20 ° C.
It is needless to say that the addition must be made within a range capable of maintaining the surface tension at 40 dyne / cm or less.

As the emulsifier or emulsion stabilizer, polyoxyethylene alkyl ether, or EO and P
Alkyl ethers with block copolymers of O are often used, and the addition amount thereof is usually in the range of about 1 to 20% by weight.

In the case where the modified epoxy resin is self-emulsifying and the aqueous solution is in an emulsion state (hereinafter abbreviated as emulsion type sizing agent), the particle size of the emulsion greatly affects the function as the sizing agent. Therefore, the average particle size must be 0.5 micron or less and substantially free of particles of 3 micron or more.

Since the reinforcing fiber bundle is usually composed of an aggregate of fine fibers having a diameter of 10 μm or less, the gap between the single fibers is extremely narrow when tension is applied to the reinforcing fibers, 3 μm or more. Since the particles of No. 2 adhere only to the surface of the fiber bundle and do not easily penetrate into the inside of the fiber bundle, it is extremely difficult to uniformly size even the single fibers located inside.

Further, even with a sizing agent using a water-soluble epoxy resin as described in JP-B-4-8542, several hundreds of sizing agents are used in a short sizing step of 10 seconds or less which is usually carried out industrially. In the above multifilament or tow-shaped filaments, it is difficult to sufficiently permeate the inside of the filament due to the high surface tension of water and the hydrophobicity of the reinforcing fiber.

In order to overcome this, it is necessary to lower the surface tension of the aqueous solution of the sizing agent composition to an appropriate range. However, in the sizing agent composition of the present invention, a specific water-soluble solution is used as described later. Penetrants have contributed effectively.

In the present invention, a water-soluble fluorinated alkyl compound or a water-soluble polysiloxane compound used as a penetrating agent is used. Typical examples of these are the following general formula (4):
The compound represented by (5) is preferably used, but the compound is not limited thereto, and any compound capable of suitably reducing the surface tension of the aqueous solution may be used.

[0038]

[Chemical 4]

[0039]

[Chemical 5]

For example, in the formula (4), part of F may be H or a halogen element other than fluorine.

Further, —CH ₃ in the formula (5) is a lower alkyl group having a carbon number n of 10 or less represented by C _n H _{2n + 1} or a phenyl group, or a part of H is substituted with a halogen element. It may be an alkyl group. Furthermore, a part of the terminal or side chain is a hydroxyl group,
Those substituted with a sulfonic acid group or an aminoalkyl group are also included.

Such a penetrant has a function of reducing the surface tension of the aqueous solution of the sizing agent composition when the sizing agent composition of the present invention is applied to the reinforcing fibers, and is a water-soluble fluorinated alkyl group. A single compound or a mixture of a plurality of compounds, or a mixture of a plurality of compounds may also be used in the water-soluble polysiloxane compound.

It is also possible to employ a mixture of a water-soluble fluorinated alkyl compound and a water-soluble polysiloxane compound.

In the present invention, the penetrant consisting of the water-soluble fluorinated alkyl compound and / or the water-soluble polysiloxane compound described above is added to the solid content of the water-soluble or self-emulsifying epoxy resin modified product. 0.05-5.
It is essential to add 0% by weight, whereby the surface tension of a 1% aqueous solution of the sizing agent composition at 20 ° C. is 40 dyne / cm or less, preferably 35 dyne / cm.
It is possible to reduce it to cm or less.

Here, the amount of the penetrant added to reduce the surface tension is industrially advantageous as it is small, but 0.05% by weight or less is not sufficient. In addition, if the penetrant is added in an amount of 5.0% by weight or more, not only does the effect of lowering the surface tension not be further exhibited, but also the adhesiveness between the reinforcing fiber and the matrix may be impaired when the reinforcing fiber is used as a composite material, which is dangerous. is there. Therefore, the amount of penetrant added is 0.05-
A range of 5.0% by weight is preferred.

As described above, it is needless to say that the penetrant to be added is not limited to one kind, and two or more kinds may be appropriately mixed and used. The preferred range of the total amount is 0.05 to 5.0% by weight.

A water-soluble compound containing 0.05 to 5.0% by weight of one or more penetrants composed of a water-soluble fluorinated alkyl compound or a water-soluble polysiloxane compound as an active ingredient, or self-contained in water. Use of an emulsifying epoxy resin modified product, and the surface tension of its aqueous solution or aqueous emulsion solution (hereinafter referred to as aqueous solution) is 2
40 dyne / cm or less at 0 ° C., preferably 35
dyne / cm or less, and in the case of a water-based emulsion, the average particle size of the emulsion is 0.5 micron or less, and a reinforcing fiber bundle is formed by using a water-based sizing agent solution containing no particles of 3 micron or more. It is possible to effectively size in a short time.

By using the aqueous solution of the sizing agent composition according to the present invention, even the reinforcing fibers composed of several hundred or more monofilaments can be uniformly sized even on the surface of the monofilaments located inside the fiber bundle. Since the agent is applied, the aggregation of the fibers is maintained well even in the process of manufacturing the composite material, and the operational inconveniences such as fluffing due to the cutting of the fibers, winding around the roller, and catching on the guide are remarkably improved. , It has become possible to efficiently produce high quality composite materials.

The sizing agent composition for reinforcing fibers according to the present invention is further improved in smoothness and bundling property of reinforcing fibers within a range in which the surface tension of an aqueous solution having a concentration of 1% by weight at 20 ° C. is not increased to 40 dyne / cm or more. Desired leveling agent,
There is no problem in using a softening agent, a sizing agent, and other improving agents in combination.

Examples of the improver compounded for this purpose are ester compounds of higher fatty acid and EO homopolymer (POE), block or random copolymer of higher fatty acid, EO and PO (POE / PPO). ) Ester compound with higher alkyl alcohol and POE or POE / PP
Examples thereof include an ether compound with an O block or a lacdam copolymer. The compounding ratio of these improvers varies greatly depending on the properties to be improved, but is generally 1/10 to 20/10 by weight with respect to the epoxy resin modified product.

In the industrial use of the sizing agent composition for reinforcing fiber of the present invention, the composition is prepared in water or a mixed solution of water and an organic solvent at an appropriate concentration, usually 0.1 to 10% by weight. %
It is used as a solution dissolved in or an emulsified emulsion solution.

The above-mentioned modifier may be added later to the aqueous solution of the sizing agent composition, or may be mixed with the sizing agent composition and then dissolved in water or a mixed solution of water and an organic solvent.

Therefore, the sizing agent composition of the present invention is 1) a water-soluble and / or self-emulsifying epoxy resin modified body as a main ingredient 2) a specific water-soluble penetrant 3) an emulsion stabilizer 4) optionally added It is a composition composed of an improving agent which is optionally incorporated.

However, as mentioned above, 3) and 4) do not necessarily have to be used in combination and only 1) and 2) may be combined, and 3) and 4) are mixed for the purpose of producing a complementary effect. It is a thing.

[0055]

When a water-based solution of the sizing agent composition of the present invention is applied to the sizing of reinforcing fibers, high-quality reinforcing fibers capable of improving excellent sizing properties, operability in the subsequent steps, quality of molded products, etc. The reason is not always explained clearly, but it is presumed that it is largely due to the following reasons.

A fine hydrophilic sizing substance having an average particle size of 0.5 micron or less rapidly penetrates into the reinforcing fibers in combination with a low surface tension to uniformly coat the surface of each single fiber. Therefore, it is possible to uniformly prevent damage to the reinforcing fiber derived in the operation in the subsequent process and suppress the generation of fluff, and not only have appropriate flexibility and smoothness, but also to spread the reinforcing fiber widely. It is thought that this is because it also has the appropriate spreadability required for.

[0057]

EXAMPLES In order to describe the present invention more specifically, typical examples will be shown below, but the present invention is not limited to the scope of these examples. The% shown in the following examples is% by weight unless otherwise specified.

In this example, the physical properties of the strand, the interlaminar shear strength (ILSS), the amount of the sizing agent composition deposited, the particle size of the emulsion and the surface tension were measured by the following methods.

(1) Measurement of Physical Properties of Strand According to the method of JIS-7601, a resin-impregnated strand was prepared by using a mixed solution of Epicoat # 828/3 boron fluoride monoethylamine / methyl ethyl ketone = 100/3/30 as a resin solution, It was measured after curing at 130 ° C. for 30 minutes.

(2) Measurement of ILSS A test piece was formed by laminating a unidirectional prepreg prepared by using a 3501 resin system manufactured by Hercules Co., Ltd., and molded into a test pinse having a length of 20 mm, a width of 6 mm and a thickness of 2 mm. ILSS was obtained from this by a 3-point bending test.

(3) Measurement of Adhesion Amount of Sizing Agent About 5 g of the fiber provided with the sizing agent composition was placed in a Soxhlet extractor and extracted with methyl ethyl ketone for 2 hours,
It was calculated from the weight difference between the fibers before and after extraction.

(4) Measurement of particle size of emulsion The particle size of an aqueous solution of the sizing agent composition having a concentration of 1% by weight was measured by the centrifugal sedimentation method. The apparatus used was a Horiba particle size distribution analyzer CAPA-700.

(5) Method of measuring surface tension The aqueous solution of the sizing agent composition having a concentration of 1% by weight at 20 ° C. was determined by the Wilhelmy method. The apparatus used was a Kyowa Scientific surface tension measuring instrument Kyowa CBVP type.

Example 1 A polyacrylonitrile-based precursor composed of 16000 denier / 12000 filaments was flame-resistant and carbonized, then surface-treated by electrolytic oxidation, washed with water, and dried with a roller to obtain a water content of about 100% (water / water). After squeezing so that the carbon fiber = about 50/50), the wet carbon fiber bundle is treated with an aqueous solution of the sizing agent composition shown in Table 1 below, and then a hot air drying cylinder at 130 ° C. And dried for 1 minute. The concentration of the sizing agent composition was 0.6%, and the sizing agent composition was applied by the roller touch method. The time from the treatment with the aqueous solution of the sizing agent composition until entering the drying cylinder was 3.5 seconds.

The carbon fiber bundle which had been subjected to the drying step after applying the sizing agent composition was brought into contact with a chrome-plated guide bar having a diameter of 10 mm, bent upward at a right angle and pulled out, and wound up by a winder. Table 1 also shows the sizing properties of the wound carbon fiber bundles. As the penetrant, a water-soluble fluorinated alkyl compound represented by the above formula (4) (trade name: Surflon S-141 Asahi Glass Co., Ltd.) was used.

[0066]

[Table 1]

As is clear from these results, carbon fibers having a good binding property were obtained by adding a penetrant comprising a water-soluble fluorinated alkyl compound in an amount of 0.05% by weight or more to reduce the surface tension. On the other hand, in the comparative examples (Sample Nos. 1 and 8) in which the penetrating agent was not added, when the fiber bundle was spread by contacting with the guide bar, the sizing agent sufficiently penetrated into the portion located inside the fiber bundle. Not only was the focusing property inferior because it was not carried out, but the occurrence of fluff was also noticeable.

The sample No. used here is Since the sizing agent compositions 1 to 7 are water-soluble, the aqueous solution was transparent and no particles were observed.

On the other hand, sample No. of the comparative example. 8 and 9 are emulsions obtained by emulsifying a commercially available epoxy resin (bisphenol A diglycidyl ether, average molecular weight 470) using a nonionic emulsifier, and the average particle size was measured to be 0.76 micron. It contained 7% of particles of 3 microns or more. When this was observed with a scanning electron microscope, it was confirmed that particles of the sizing agent were unevenly distributed on the surface of the carbon fiber bundle.

Comparative Example Sample No. No. 9 is a comparative example. 8 has the same penetrant as in the present invention added,
Since the surface tension of the sizing agent emulsion solution is lowered, the sample No. Although the bundling property is slightly improved as compared with No. 8, the bundling property is inferior to that of the present invention because the particles of the sizing agent are unevenly distributed.

Sample No. 1 (comparative example) is a water-soluble sizing agent, but since the surface tension of the aqueous solution is high, the permeability into the inside of the fiber bundle is poor, and the focusing property of the fibers located inside is poor. Occurrence of fluff was remarkable when the bundle was spread.

Sample No. Sample No. 8 (Comparative Example) Similar to No. 1, the bundle had poor focusing properties and had a lot of fuzz.
Sample No. Sample No. 9 is Although the number of fluffs was less than that of Sample Nos. 1 and 8, Sample No. It did not reach 2-7.

Example 2 Single yarn denier 0.8 / 1200 obtained by spinning a copolymer consisting of 98% acrylonitrile and 2% methacrylic acid.
0 filament precursor, 220 ℃, 235
C., 250.degree. C., and retained in a hot air circulation type flameproofing furnace for 20 minutes each to make it flameproof, then the maximum temperature 500.degree.
It was continuously carbonized using a carbonization furnace at 1400 ° C. The carbonized fiber was subjected to a surface treatment by an electrolytic oxidation method using ammonium bicarbonate as an electrolyte, washed with water, and then squeezed with a roller so that the water content was about 100%, and the same penetrant as in Example 1 was used. It was sized with a 1.3% aqueous solution of 5% POE (30) bisphenol A glycidyl ether and dried. The strand strength and ILSS of the carbon fiber thus obtained were measured, and the results are shown in Table 2.

[0074]

[Table 2]

As is clear from Table 2, the sample No. 1 according to the present invention. 11 to 17, ILSS is a comparative example sample No. in which a penetrant is not added. You have beaten ten.

On the other hand, sample N containing 5.5% penetrant
o. 18, ILSS was slightly lowered.

Even if the penetrant is added in an excessive amount, the surface tension of the aqueous solution of the sizing agent composition does not decrease to 25 dyne / cm or less, and rather, the ILSS decreases. Is 0.05 to 5.
0% is suitable.

Example 3 In a water-soluble epoxy resin modified product [POE (30) bisphenol A glycidyl ether], a water-soluble polysiloxane [a polysiloxane represented by the formula 5 and R is C
₃ H ₆ , X is (C ₂ H ₄ O) _l , l = 15, x = 30,
The surface tension of an aqueous solution of a sizing agent composition containing 0 to 2% of y = 3] was measured, and the results are shown in Table 3. By adding the water-soluble polysiloxane-based penetrant, the surface tension of the aqueous solution of the sizing agent composition was suitably reduced.

[0079]

Example 4 Epoxy resin modified product self-emulsifying in water [PO
E (5) Bisphenol A glycidyl ether] was added with the same penetrant as in Examples 1 and 3, and the surface tension of the 1% solution was measured. The results are shown in Table 4. By the addition of the penetrant, the surface tension of the aqueous solution of the sizing agent composition was obviously lowered. The emulsions in this sizing agent composition aqueous solution each had an average particle size of 0.1 micron, and particles of 3 micron or more were not detected.

[0081]

Example 5 As a sizing agent composition, a 1.5% aqueous solution of a mixture of POE (30) bisphenol A glycidyl ether / POE (15) rosin ester = 2/1 was added to a fluorine-based penetrant (Surflon S-141). The carbon fiber obtained by treating in the same manner as in Example 2 except that 0.5% was added has good sizing property, has no fluff in the prepreg processing step, and has a high commercial value of 75 per square meter. A thin gram of prepreg sheet was obtained. The surface tension of the aqueous solution of the sizing agent composition used here was 30 dyne / c.
It was m. The carbon fiber strand strength is 570 kg.
/ Mm ² and ILSS were 12.8 kg / mm ² .
When such an appropriate sizing agent is blended, the handling of the composite material in the processing step becomes easier.

Example 6 As a sizing agent composition, POE (30) bisphenol A glycidyl ether was used, and alcohol or methyl ethyl ketone was added to this 1% aqueous solution at 95/5, 9/5.
With respect to the solution mixed so as to have a volume ratio of 0/10, the effect of reducing the surface tension by adding the penetrant was clarified. The results are shown in Table 5. The same penetrant as in Example 1 was used. As is clear from this result, it is difficult to reduce the surface tension of the sizing agent solution to the range of the present invention simply by mixing a low surface tension organic solvent, and it is necessary to use an appropriate penetrant in combination. It is understood to be achieved.

[0084]

[Table 3]

Example 7 0.8% of the same sizing agent as in Example 5 was applied to alumina long fibers (manufactured by Sumitomo Chemical Co., Ltd.) consisting of 10,000 single filaments each having a diameter of 9 microns, and then continuously dried in a drying tube at 130 ° C. It was dried and wound on a winder. Even though the dipping time in the sizing bath is 2.5 seconds, which is extremely short, the inside of the fiber bundle is uniformly sized, so that the obtained alumina fiber has very little fuzzing and proper sizing ability. There was excellent operability in post-processing such as prepreg and filament winding. On the other hand, POE (30) bisphenol A glycidyl ether / POE (15) rosin ester with no penetrant added = 2 /
1.5% solution of the mixture of 1 (surface tension 43 dyne / c
The product treated in the same manner as m) had a portion where the sizing agent was not applied inside the fiber bundle, so that the damage of the fiber in the winder was conspicuous and the appearance was not good and the commercial value was poor.

[0086]

INDUSTRIAL APPLICABILITY According to the present invention, the effect of appropriately setting the average particle diameter of the modified epoxy resin and the penetrant as the essential component and the appropriate setting of the surface tension by the penetrant are achieved. Even if the object of sizing is a hydrophobic reinforcing fiber bundle, the sizing agent can be evenly applied to the inside of the fiber bundle easily in a short time.

Further, since the aqueous solution of the sizing agent composition of the present invention does not use an organic solvent to the extent that flammability and harmfulness to the human body pose a problem, it is also suitable for work environment and work safety. Since the agent composition can be provided, industrially advantageous sizing can be performed on the reinforcing fiber. The reinforcing fiber is preferably applied not only to carbon fiber but also to many fibers such as aramid fiber, wholly aromatic polyester fiber, glass fiber and alumina fiber.

Claims (2)

[Claims] 1. A penetrant comprising a water-soluble or self-emulsifying epoxy resin modified product and a penetrant comprising a water-soluble fluorinated alkyl compound and / or a water-soluble polysiloxane compound as essential components. In an amount of 0.05 to 5.0% by weight based on the modified epoxy resin, wherein the surface tension of a 1% by weight aqueous solution of the sizing agent composition is 40 dyn at 20 ° C.
In the epoxy resin modified product having an e / cm or less and having a self-emulsifying property with respect to water, the average particle diameter of the emulsion in the aqueous solution is 0.5 μm or less,
A sizing agent composition for reinforcing fibers, which is characterized by not containing particles of 3 microns or more. 2. A compound obtained by adding a polyether to an epoxy resin, or a compound obtained by further epoxidizing an epoxy resin after adding a polyether to the epoxy resin, wherein the water-soluble or self-emulsifying epoxy resin modified product is, The sizing agent composition for reinforcing fibers according to claim 1, which is a compound obtained by epoxidizing a polyether derivative of a dihydroxy compound.