JP2000191341A - Sizing agent for glass fiber and glass fiber coated with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain glass fibers having superior properties of coating, superior flying property, oil removability and suitability to bundling by carrying out coating with a sizing agent containing starch and an alkyl polyoxyethylene ether or an alkylphenyl polyoxyethylene ether. SOLUTION: The starch may be ordinary raw starch such as cornstarch, high-amylose starch, a starch hydrolyzate subjected to oxidation treatment or a chemically modified starch derivative. The starch content is 2.0-10 wt.%. The alkyl polyoxyethylene ether is, e.g. polyoxyethylene lauryl ether. The alkylphenyl polyoxyethylene ether is, e.g. polyoxyethylene nonylphenyl ether. The ether content is 0.1-1.0 wt.%. The HLB of the ethers is preferably 8-16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition of a sizing agent for glass fibers and a glass fiber coated with the sizing agent.

[0002]

2. Description of the Related Art A glass fiber strand is produced by collecting and winding a plurality of glass fiber filaments obtained by drawing a molten glass. At this time, in order to prevent yarn breakage and fuzzing due to friction between the glass fibers and the glass fiber and the guide in the subsequent process,
The glass fibers are coated with a sizing agent.

[0003] Depending on the use of the glass fiber, the glass fiber strand is twisted into a glass fiber yarn, and the glass fiber yarn is woven to obtain a glass fiber fabric. Glass fiber fabric is sometimes used as a reinforcing material for printed wiring boards and other reinforced plastic products by impregnation with resin. At this time, in order to strengthen the adhesive force between the glass fiber fabric and the resin, the glass fiber fabric is subjected to a surface treatment with a silane coupling agent before impregnation with the resin. Generally, prior to the surface treatment of the glass fiber fabric with the silane coupling agent, the glass fiber fabric is incinerated at 350 to 450 ° C. to remove the oil by thermally decomposing and removing organic substances such as a sizing agent coating the glass fiber surface. I do.

[0004] On the other hand, with respect to the characteristic requirements associated with high-density mounting, multi-layering, and thinning of printed wiring boards, and with respect to the characteristic requirements associated with speeding up in the weaving process using an air jet loom, glass fiber is particularly preferred. Many known techniques have been disclosed with respect to the composition of a sizing agent for glass fibers used in glass fiber woven fabrics, from the viewpoint of preventing generation of fluff and improving oil removal. For example, a sizing agent composition containing a polyoxyalkylene polyol or a polyalkyl polyol is disclosed in
No. 7651. A sizing agent composition containing starch and an ammonium sulfate compound is disclosed in JP-A-8-10454.
No. 8. A sizing agent containing starch and having a specific compounding ratio is disclosed in JP-A-3-183644. A sizing agent composition containing a specific starch derivative is disclosed in JP-A-53-35639 and JP-A-4-76338. However, although the glass fiber woven fabric obtained by weaving the glass fiber coated with the sizing agent having the composition of the known art has excellent properties, it can sufficiently satisfy the property requirements of the glass fiber woven fabric. Absent.

[0005] In general, increasing the ratio of starch to the sizing agent component can reduce the generation of fluff and improve the deoiling property. However, the glass fibers are excessively adhered to each other and the glass fiber strands are hardened, resulting in poor weaving. Decrease. Therefore, in the sizing agent having the composition of the well-known technology including the above-described well-known technology, the starch content is 2.0 to 4.0% by weight, and the starch content ratio to the sizing agent component is 65% by weight or less.

[0006]

An object of the present invention is to provide a glass fiber having the following characteristics (a) to (c) by coating the glass fiber with a specific sizing agent. . (A) Deoilability, which is a property of glass fibers that quickly completes an incineration deoiling process that causes a decrease in tensile strength. (B) Coating properties, which are properties that prevent the occurrence of yarn breakage and fluffing of glass fibers in the steps after the step of drawing molten glass. (C) In weaving by an air jet loom, flight performance is a characteristic that prevents a trouble in the process that a weft cannot reach a predetermined position without riding on air. (D) Convergence, which is a property for obtaining a convergence state suitable for impregnating a glass fiber fabric with a resin.

[0007]

The sizing agent for glass fibers in the present invention is characterized by containing starch and alkylpolyoxyethylene ether or alkylphenylpolyoxyethylene ether.

Further, in the sizing agent for glass fibers, the content of the sizing agent component is preferably the following (a) and / or (b). (A) The starch content is 2.0 to 10.0% by weight, more preferably 4.0 to 8.0% by weight. (B) The content of alkylpolyoxyethylene ether or alkylphenylpolyoxyethylene ether is 0.1 to 1.0% by weight, more preferably 0.1 to 1.0% by weight.
2 to 0.5% by weight.

Further, in order to exert a remarkable effect on the object of the present invention, the sizing agent may contain an ammonium sulfate compound. The content of the ammonium sulfate compound is preferably from 0.1 to 1.0% by weight, and more preferably from 0.1 to 0.5% by weight.

That is, the present invention provides a composition of a sizing agent for glass fibers which can be prepared so that the content ratio of starch in the sizing agent component can be adjusted to a higher ratio than known techniques and can contain an ammonium sulfate-based compound. . Further, the present invention is to provide a glass fiber which is obtained by coating a glass fiber with the sizing agent and exhibiting excellent covering properties, flight properties, deoiling properties and sizing property.

[0011] In the sizing agent for glass fibers, generally, when the content ratio of starch is increased, the film-forming property and the oil-removing property are improved, but the sizing property and flight property of the glass fiber are reduced. In order to solve this, an alkyl polyoxyethylene ether or an alkyl phenyl polyoxyethylene ether is contained in a sizing agent to impart flexibility to a glass fiber strand and obtain favorable properties as a glass fiber.
This is because the alkylpolyoxyethylene ether or the alkylphenylpolyoxyethylene ether acts as a plasticizer on the starch and covers the surface of the starch granules, thereby suppressing the swelling of the starch granules and binding the starch granules. In addition to blocking, it forms a complex with amylose in the starch granules, prevents elution of amylose out of the granules, prevents the formation of hard amylose gel between the starch granules, and obtains a flexible glass fiber strand. Inferred.

Further, in the sizing agent of the present invention, the ammonium sulfate compound functions to further improve the sizing property, the flying property and the deoiling property. This is considered to be due to the following reasons.

That is, glass fibers coated with a sizing agent containing an ammonium sulfate-based compound have low adhesiveness between glass fibers in a wet state. Therefore, it is easy to control the amount of the sizing agent attached, and it is easy to separate even if it adheres to the adjacent glass fiber yarn due to vibrations during drying, etc. It is easy to move into the glass fiber yarn and the amount of sizing agent between adjacent glass fiber yarns is reduced. This is presumably because a glass fiber strand having good division properties was obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The components constituting the sizing agent for glass fibers are intricately related to each other and cannot be strictly classified according to their functions. The glass fiber sizing agent comprises a film forming agent, a lubricant, a softener, an emulsifier, a preservative, and the like, and is coated on the glass fibers in the form of an aqueous preparation.

As the film forming agent, polyvinyl alcohol can be used in addition to starch for the purpose of forming a film for protecting the glass fiber from bending and friction during the process. In the sizing agent of the present invention, starch is used as a film-forming agent. The sizing agent of the present invention does not prevent the combination with polyvinyl alcohol, and in this case, the starch content can be reduced. Starch is ordinary raw starch such as corn starch, high amylose type starch, enzyme-modified starch,
Alternatively, starch degradation products subjected to acid treatment, wet heat treatment, or oxidation treatment, or starch derivatives chemically modified such as cross-linking, esterification, etherification, or grafting may be used. In the sizing agent of the present invention, one or more kinds of starch may be appropriately selected depending on the use of the glass fiber.

In the sizing agent of the present invention, if the starch content is less than 2.0% by weight based on the sizing agent, fluffing or yarn breakage may occur due to a decrease in the coating property of glass fibers, and 10.0% by weight. %, Fluffing and yarn breakage may occur due to adhesion with adjacent glass fiber yarns.

Lubricants are used to provide slip to the strands, reduce friction and protect glass fibers. Examples of the type of lubricant include hardened oil obtained by hydrogenating animal and vegetable oils, paraffin wax, ester condensates of higher saturated fatty acids and higher saturated alcohols, and the like. In the sizing agent of the present invention, the type of the lubricant and the content with respect to the sizing agent may be selected according to the use of the glass fiber,
There is no particular limitation.

The softener is used for the purpose of softening hard glass fiber strands and selectively adhering to the glass surface to provide lubricity in order to reduce friction between filaments in the strands. In the sizing agent of the present invention, an alkyl polyoxyethylene ether or an alkylphenyl polyoxyethylene ether is used.

Alkyl polyoxyethylene ethers and alkyl phenyl polyoxyethylene ethers belong to the nonionic activators, but alkyl esters, sorbitan derivatives, and propylene oxide / ethylene oxide block copolymers belonging to the same nonionic activator include: The effect as a softener is small.

Examples of the alkyl polyoxyethylene ether used in the sizing agent of the present invention include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether and the like. can do. Examples of the alkylphenyl polyoxyethylene ether include polyoxyethylene nonyl phenyl ether and polyoxyethylene octyl phenyl ether.

In the sizing agent of the present invention, the alkylpolyoxyethylene ether or alkylphenylpolyoxyethylene ether as a softener preferably has an HLB (lipophilic hydrophilic balance) of 8 to 16,
More preferably, the number is from 12 to 16. However,
HLB = E / 5 (E; ethylene oxide content [% by weight]) When the HLB is less than 8 or more than 16, emulsification of the lubricant becomes insufficient, and an effect satisfying the object of the present invention is obtained. May not be possible.

In the sizing agent of the present invention, if the content of the alkyl polyoxyethylene ether or the alkylphenyl polyoxyethylene ether is less than 0.1% by weight with respect to the sizing agent, necessary flexibility may not be obtained,
If it exceeds 1.0% by weight, it becomes excessively soft and may cause fluffing or yarn breakage.

In addition to the above-mentioned alkyl polyoxyethylene ethers or alkylphenyl polyoxyethylene ethers as softening agents, cationic activities such as amides or imidazolines obtained by reacting tetraethylene pentamine with stearic acid, quaternary ammonium salts, etc. Agents and the like. The sizing agent of the present invention does not prevent the combination with other softeners other than the alkylpolyoxyethylene ether or the alkylphenyl polyoxyethylene ether.

The emulsifier uses a nonionic activator mainly for the purpose of emulsifying a lubricant. The alkyl polyoxyethylene ether or alkyl phenyl polyoxyethylene ether contained in the sizing agent of the present invention is considered to be a nonionic activator and also acts as an emulsifier. In the sizing agent of the present invention, a nonionic activator other than alkylpolyoxyethylene ether or alkylphenylpolyoxyethylene ether, for example, an alkyl ester, a sorbitan derivative, or a propylene oxide / ethylene oxide block copolymer can also be used as the emulsifier. May be appropriately selected depending on the compatibility with other components and the use of the glass fiber. The sizing agent of the present invention does not prevent the combined use of an alkyl polyoxyethylene ether or an alkylphenyl polyoxyethylene ether with other nonionic activators.

The ammonium sulfate compound which can be used in the sizing agent of the present invention is represented by the formula (1). R ₁ —SO ₄ —R ₂ Formula (1) In the formula, R ₁ is ammonium or a group containing ammonium, and R ₂ is ammonium, a group containing ammonium, or an organic group other than these. R
_1, the group having an ammonium in R _2, triethylammonium, octyl triethylammonium,
Oleylamidopropyldimethylammonium, stearyldiacetylmethylammonium and the like can be exemplified. R ₂ may be any functional group as long as it does not hinder the water solubility of the ammonium sulfate compound, and examples thereof include an alkyl group, an alkyl arene group, an aryl group, an alkenyl group, and an alkynyl group.

From the combination of these functional groups, ammonium sulfate compounds used in the present invention include trimethylammonium sulfate, triethylammonium sulfate, tributylammonium sulfate, octyltrimethylammonium ethosulfate, laurylamidopropyltriethylammonium methosulfate, and stearylamidodihydrooxy. Ethyl methyl ammonium methosulfate, stearyl diacetyl methyl ammonium methosulfate and the like can be exemplified.

In the sizing agent of the present invention, if the content of the ammonium sulfate compound is less than 0.1% by weight of the sizing agent, the oil-removing property may not be improved. Flushing and yarn breakage may occur.

As a preservative, formalin is mainly used. In the sizing agent of the present invention, the kind of the preservative and the content relative to the sizing agent are not particularly limited.

The method for preparing the sizing agent of the present invention may be in accordance with a known method. In the glass fiber of the present invention, when coating the glass fiber with a sizing agent, the amount of the sizing agent attached to the glass fiber is 0.1 to 0.1% after drying the glass fiber.
It is 10.0% by weight, preferably 0.5 to 1.5% by weight. If the amount is less than 0.5% by weight, fluffing or yarn breakage may occur due to a decrease in film properties, and 10.0% by weight
If the ratio exceeds the above, troubles due to reduced flight performance may occur.

In the glass fiber of the present invention, the glass composition, the diameter and shape of the glass fiber filament, the number of filament bundles of the glass fiber strand and the twisting method,
The weaving method for obtaining the glass fiber fabric, the incineration and deoiling conditions for the glass fiber fabric and the resin impregnation method, and the type of the silane coupling agent for surface treating the glass fiber fabric can be appropriately selected depending on the use of the glass fiber. Well, there is no particular limitation. In the present invention, the warp is preferably coated with a secondary sizing agent when weaving. The present invention does not limit the composition of the secondary sizing agent.

[0031]

EXAMPLES [Example 1] (1) Preparation of sizing agent 2500 g of high amylose etherified starch and 2500 g of etherified starch were dispersed in 80 kg of pure water and heated at 95 ° C.
And then cooled to 65 ° C. to obtain a liquid A. Hydrogenated vegetable oil 1000 g, polyoxyethylene polypropylene ether (HLB = 16) 100 g, polyoxyethylene lauryl ether (HLB = 14) 40
Warm water was added to 0 g of the mixture while stirring with a homomixer to make the total amount 4 kg. Warm water was added to 100 g of the acetic acid active substance of the condensate of tetraethylenepentamine and stearic acid to make 3 kg, thereby obtaining a liquid C. 150 g of octyltrimethylammonium ethosulfate was dissolved in 300 g of warm water to obtain a solution D. 50 g of formaldehyde was dissolved in 3 kg of water to obtain a solution E. Solution A, Solution B, Solution C, Solution D, and Solution E were added sequentially, and then hot water was added thereto to obtain a total weight of 100 kg.
Was obtained.

(2) Production of Glass Fiber Yarn The sizing agent for glass fiber described in (1) is adhered in an amount of about 1.0% by weight based on the weight of the glass fiber, and an example of ECG 75 1/0 0.7 according to JIS standard R3413 is used. One glass fiber yarn was obtained.

(3) Production of glass fiber woven fabric The glass fiber yarn obtained in (2) is used as a weft, and a secondary sizing agent having the composition shown in the following (a) is attached to the glass fiber yarn in an amount of about 1.5% by weight. The coated glass fiber yarn is treated as warp yarn,
The glass fiber fabric of Example 1 of IS standard R3414 EP18B was obtained. (A) Composition of secondary sizing agent Partially saponified polyvinyl alcohol 5.0 parts by weight High amylose type etherified starch 1.0 part by weight Paraffin wax 1.0 part by weight Formalin 0.1 part by weight Water remaining amount

Example 2 In the preparation of the sizing agent of Example 1, polyoxyethylene lauryl ether (HLB =
14) Instead of 400 g, 400 g of polyoxyethylene nonylphenyl ether (HLB = 14) was added to prepare solution B. Otherwise, the sizing agent of Example 2 was prepared in the same manner as in Example 1. Further, (2) and (3) of Example 1
The glass fiber yarn of Example 2 and the glass fiber fabric were obtained in the same manner as in Example 1.

Example 3 In the preparation of the sizing agent of Example 1, polyoxyethylene lauryl ether (HLB =
14) Instead of 400 g, 400 g of polyoxyethylene octyl phenyl ether (HLB = 13) was added to prepare solution B. Otherwise in the same manner as in the first embodiment, the third embodiment
Was prepared. Further, (2) of Example 1,
The glass fiber yarn of Example 3 and the glass fiber fabric were obtained in the same manner as in (3).

Example 4 In the preparation of the sizing agent of Example 1, polyoxyethylene lauryl ether (HLB =
14) Instead of 400 g, 400 g of polyoxyethylene nonylphenyl ether (HLB = 9) was added to prepare solution B. Otherwise in the same manner as in Example 1, the sizing agent of Example 4 was prepared. Furthermore, a glass fiber yarn and a glass fiber fabric of Example 4 were obtained in the same manner as in (2) and (3) of Example 1.

Example 5 The sizing agent of Example 5 was prepared in the same manner as in Example 1, except that the solution D was not added. Further, a glass fiber yarn and a glass fiber woven fabric of Example 5 were obtained in the same manner as in (2) and (3) of Example 1.

Example 6 The sizing agent of Example 6 was prepared in the same manner as in Example 2 except that the solution D was not added. Further, the glass fiber yarn and the glass fiber fabric of Example 6 were obtained in the same manner as in (2) and (3) of Example 1.

Example 7 The sizing agent of Example 7 was prepared in the same manner as in Example 3 except that the solution D was not added. Further, a glass fiber yarn and a glass fiber fabric of Example 7 were obtained in the same manner as in (2) and (3) of Example 1.

Example 8 The sizing agent of Example 8 was prepared in the same manner as in Example 4, except that the solution D was not added. Further, a glass fiber yarn and a glass fiber fabric of Example 8 were obtained in the same manner as in (2) and (3) of Example 1.

Example 9 A solution D was prepared by dissolving 150 g of triethylammonium sulfate in 300 g of warm water. Otherwise, the sizing agent of Example 9 was prepared in the same manner as (1) of Example 1. Further, a glass fiber yarn and a glass fiber fabric of Example 9 were obtained in the same manner as in (2) and (3) of Example 1.

Example 10 3000 g of high amylose etherified starch and 3000 g of etherified starch were dispersed in 80 kg of pure water and gelatinized at 95 ° C. for 30 minutes.
It cooled to 65 degreeC and was set as the liquid A. Hydrogenated vegetable oil 500
g, polyoxyethylene polypropylene ether (HL
B = 16) and 50 g of polyoxyethylene lauryl ether (HLB = 14) were mixed with hot water while stirring with a homomixer to make a total amount of 4 kg, thereby obtaining a liquid B. Otherwise, the sizing agent of Example 10 was prepared in the same manner as in (1) of Example 1. Further, the glass fiber yarn and the glass fiber fabric of Example 10 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 1 1000 g of hydrogenated vegetable oil
Polyoxyethylene polypropylene ether (HLB =
16) 100 g of polyoxyethylene sorbitan monolaurate (HLB = 13) (400 g) was added with warm water while stirring with a homomixer to make a total amount of 4 kg to obtain a liquid B. In addition, 300 g of water was used as solution D. Otherwise, the sizing agent of Comparative Example 1 was prepared in the same manner as in Example 1, (1). Further, a glass fiber yarn and a glass fiber fabric of Comparative Example 1 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 2 Hydrogenated vegetable oil 1000 g,
Polyoxyethylene polypropylene ether (HLB =
16) 100 g of polyethylene glycol monolaurate (HLB = 14) (400 g) was added to warm water while stirring with a homomixer to make a total amount of 4 kg, thereby obtaining a liquid B. Water 3
00 g was used as solution D. Otherwise, the sizing agent of Comparative Example 2 was prepared in the same manner as in (1) of Example 1. Further, a glass fiber yarn and a glass fiber fabric of Comparative Example 2 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 3 1000 g of hydrogenated vegetable oil
Polyoxyethylene polypropylene ether (HLB =
16) Warm water was added to 100 g of the mixture while stirring with a homomixer to make the total amount 4 kg, thereby obtaining a liquid B. 500 g of acetic acid active substance of condensate of tetraethylenepentamine and stearic acid
Was added to warm water to make up to 3 kg to obtain a liquid C. Otherwise, the sizing agent of Comparative Example 3 was prepared in the same manner as in Example 1, (1). Further, a glass fiber yarn and a glass fiber fabric of Comparative Example 3 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 4 1000 g of hydrogenated vegetable oil,
Polyoxyethylene polypropylene ether (HLB =
16) Warm water was added to 100 g of the mixture while stirring with a homomixer to make the total amount 4 kg, thereby obtaining a liquid B. 500 g of acetic acid active substance of condensate of tetraethylenepentamine and stearic acid
Was added to warm water to make up to 3 kg to obtain a liquid C. 300 g of water D
Liquid. Otherwise, the sizing agent of Comparative Example 4 was prepared in the same manner as in Example 1 (1). Furthermore, a glass fiber yarn and a glass fiber fabric of Comparative Example 4 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 5 1800 g of high amylose etherified starch and 1800 g of etherified starch were mixed with pure water 8
0 kg, and gelatinized at 95 ° C. for 30 minutes.
It cooled to 5 degreeC and was set as the liquid A. Hydrogenated vegetable oil 1300
g, 1300 g of paraffin wax and 260 g of polyoxyethylene polypropylene ether (HLB = 16) while stirring with a homomixer, add hot water and add 4 kg in total.
And used as solution B. 300 g of water was used as solution D. Otherwise, the sizing agent of Comparative Example 5 was prepared in the same manner as in Example 1, (1). Further, a glass fiber yarn and a glass fiber woven fabric of Comparative Example 5 were obtained in the same manner as in (2) and (3) of Example 1.

Comparative Example 6 Hydrogenated vegetable oil 1000 g,
Polyoxyethylene polypropylene ether (HLB =
16) Warm water was added to 100 g of the mixture while stirring with a homomixer to make the total amount 4 kg, thereby obtaining a liquid B. 150 g of octyltrimethylammonium ethosulfate in 300 parts of warm water
g and used as solution D. Otherwise (1) of Example 1
The sizing agent of Comparative Example 6 was prepared in the same manner as described above. further,
In the same manner as in (2) and (3) of Example 1, a glass fiber yarn and a glass fiber fabric of Comparative Example 6 were obtained.

Table 1 shows the composition of the sizing agent of each Example, and Table 2 shows the composition of the sizing agent of each Comparative Example.

[0050]

[Table 1]

[0051]

[Table 2]

[Evaluation] The properties of the glass fiber yarn, glass fiber fabric or laminate obtained in each of the examples and comparative examples were measured in the following manner. Since the convergence of the glass fiber directly affects the impregnation of the glass fiber fabric with the resin, the impregnation of the resin was evaluated and the convergence was indirectly evaluated.

(A) Coverability: The number of fluffs per 1000 m of glass fiber of each of the glass fiber fabrics of Examples and Comparative Examples was measured by a fluff counter manufactured by Toray Industries, Inc.

(B) Flying property: The tip of the glass fiber yarn bobbin of each of Examples and Comparative Examples was passed through an air nozzle, and the weight of the glass fiber yarn flying per minute at an air pressure of 1 kgf / cm ² was measured.

(C) Deoiling property: 200 pieces of 20 cm * 20 cm pieces of the glass fiber woven fabrics of the respective Examples and Comparative Examples were superimposed, subjected to a load, and thermally deoiled in an oven at 400 ° C. for 24 hours. (CIE) The color tone of the central portion of the 100th glass fiber woven piece from the top was measured by the color sensation color b *.

(D) Resin impregnation; FR according to JIS standard
-4 type epoxy resin varnish with solvent at 150 cps
The glass fiber woven fabric of each of Examples and Comparative Examples
A piece of 0 cm * 10 cm was gently floated, and the time until the bubbles in the glass fiber completely disappeared was measured.

The measurement results for (a) to (d) were evaluated in five grades according to the procedure shown in Table 3. The grades in Table 3 indicate that smaller ones have better properties. Table 4 shows the evaluation results.

[0058]

[Table 3]

[0059]

[Table 4]

In the well-known sizing agent for glass fibers (Comparative Example 5), the starch content ratio to the sizing agent component was about 55.
% By weight. When the starch content is increased to 75% by weight or more (Comparative Example 6), the deoiling property of the glass fiber is improved, but the other properties are reduced. The sizing agent having a high starch content ratio cannot satisfy the required properties of the glass fiber even if the softener content is changed (Comparative Example 4) and an ammonium sulfate-based compound is further added (Comparative Example 3).

However, a glass fiber satisfying the required characteristics can be obtained by using a sizing agent containing an alkyl polyoxyethylene ether or an alkylphenyl polyoxyethylene ether as a softener (Examples 5 to 8). Furthermore, a glass fiber having excellent properties can be obtained by using a sizing agent (Examples 1 to 4) obtained by adding an ammonium sulfate-based compound thereto. Example 1
In the sizing agent, even if the type of the ammonium sulfate compound was changed (Example 9) or the starch content was further increased (Example 10), glass fibers having the same excellent properties could be obtained. it can.

The sizing agent containing a nonionic activator of a sorbitan derivative (Comparative Example 1) or the sizing agent containing a nonionic activator of an alkyl ester (Comparative Example 2) does not satisfy the required properties of glass fibers. Can not.

As described above, the glass fibers coated with the sizing agent of the present invention have excellent film-forming properties, flying properties, oil-removing properties, and resin-impregnating properties (ie, sizing properties).

[0064]

The glass fiber woven fabric obtained by weaving the glass fiber coated with the sizing agent of the present invention has excellent resin impregnating properties and has little fuzzing and thread breakage. It is suitable.

Claims (6)

[Claims] 1. A sizing agent for glass fibers, comprising starch and an alkyl polyoxyethylene ether or an alkylphenyl polyoxyethylene ether. 2. The sizing agent for glass fibers according to claim 1, wherein the starch content is 2.0 to 10.0% by weight. 3. The sizing agent for glass fibers according to claim 1, wherein the content of the alkyl polyoxyethylene ether or the alkyl phenyl polyoxyethylene ether is 0.1 to 1.0% by weight. 4. The sizing agent for glass fibers according to claim 1, wherein the sizing agent for a glass fiber comprises an ammonium sulfate compound. 5. The content of the ammonium sulfate compound is as follows:
The sizing agent for glass fibers according to claim 4, which is 0.1 to 1.0% by weight. 6. A glass fiber coated with the sizing agent for glass fiber according to claim 1. Description: