JPH11100237A - Glass fiber sizing agent for frp and glass fiber strand having the same agent deposited on the same strand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the sizing agent capable of providing the FRP formed article with good water resistance and well-balanced proterties at the time of producing an FRP formed article by preparing a sizing agent contg. as essential components, three components, i.e., a coating film forming agent, a melamine resin and a melamine-resin-reactive silane coupling agent. SOLUTION: This sizing agent contains a melamine resin and a melamine- resin-reactive silane coupling agent in a total amount sufficient to provide an about 5 to 50 wt.% ratio to the weight of solid matter in the agent. The blending ratio of (weight of the melamine resin):(weight of the silane coupling agent) is about 10:1 to 1:10. The amount of the sizing agent to be deposited on a glass fiber strand is about 0.1 to 10.0 wt.% and in particularly preferably, 0.5 to 5.0 wt.%, based on the weight of the strand. As the melamine resin, a water-soluble methylated melamine resin capable of being easily dissolved into water is appropriately used. The content of the melamine resin in the sizing agent is about 5 to 50 wt.%, or preferably 7 to 35 wt.%, based on the weight of the solid matter in the sizing agent. An example of the melamine- resin-reactive silane coupling agent is an epoxysilane compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing agent for glass fibers which improves the water resistance of FRP using a matrix resin which is a thermosetting resin, particularly an unsaturated polyester resin.

[0002]

2. Description of the Related Art Generally, a glass fiber is drawn out of molten glass from several thousand nozzles and stretched while adhering a sizing agent by a known applying means such as a roller applicator or a belt applicator. 1- Divided into glass fiber bundles, also called several strands, and wound into a cake. The glass fiber bundle produced in this way is roving, chopped strand, chopped strand mat, roving.
It is used for reinforcement when it is processed into a shape such as a bing cloth and a resin molded product is manufactured. The glass fiber sizing agent for FRP has a solvent of water and a film-forming agent as a main component, and a lubricant, a softening agent, a surface treatment agent, an antistatic agent and the like are blended as required.

[0003] Film-forming agents adhere several hundreds of glass filaments to a single strand and further protect the yarn from any bending and friction during processing on subsequent processing machines or at the point of use. Used in Glass fiber sizing agents used for FRP include vinyl acetate resin, vinyl acetate copolymer resin, urethane resin,
Emulsions such as acrylic resins are often used.
These film forming agents are generally used alone or in combination of two or more.

[0004] Lubricants are used to impart slip to strands, reduce friction on the machine and protect the yarn.
As the type of the lubricant, a modified silicone oil, a hardened oil obtained by hydrogenating animal and vegetable oils, and a synthetic oil such as a condensate of a higher saturated fatty acid and a higher saturated alcohol are often used. Cationic softeners are used to soften hard glass yarns, and to reduce friction between filaments in strands. I have. For example, those obtained by reacting tetraethylenepentamine with stearic acid are used. Surfactants are mainly used as emulsifiers for lubricants, and for example, polyoxyethylene polyalkyl ether or polyoxyethylene alkyl ether is often used.

[0005] The antistatic agent has a function of removing static electricity generated when the strand runs or cuts, and inorganic salts such as lithium nitrate and lithium chloride or quaternary ammonium salts are used as materials. As the surface treatment agent, an unsaturated polyester resin having a double bond or a chemical bond with styrene in the resin is used, and a silane coupling agent such as methacrylsilane, acrylic silane, vinylbenzylaminosilane is preferably used. ing.

[0006]

The sizing agent for roving made of such a raw material has considerably excellent properties, and in many cases, it has actually been used. However, in the case of FRP products using glass fibers to which these sizing agents are attached, particularly products used around water such as bath units made of SMC and the like, and bathtubs made by the BMC method, like a 24-hour bath. , Longer time water resistance,
As hot water resistance is required, the required quality is getting stricter year by year, making it difficult to satisfy all.
In order to satisfy these requirements, improvement of a glass fiber sizing agent for strengthening the bond between the glass fiber and the resin is desired. An object of the present invention is to solve the above-mentioned problems and to provide a sizing agent which has good water resistance when formed into an FRP molded product and can obtain various properties conventionally required in a well-balanced manner. .

[0007]

In order to achieve the above object, the present invention provides at least a melamine resin and a melamine-reactive silane coupling agent in a sizing agent in a solid content of 5-5%.
A first aspect of the present invention is a glass fiber sizing agent characterized by containing 0% by weight, and the solid content of the sizing agent is 0.1 to 10.0.
A second feature of the present invention is a glass fiber characterized by being attached by weight%.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A sizing agent for glass fibers comprising the melamine resin and the silane coupling agent of the present invention in a sizing agent solid content of 5 to 50% by weight improves the sizing ability of the glass fiber strand. This improves workability during use, such as preventing fluffing and cutting of glass fibers, and suppressing various problems caused by static electricity. At the same time, when making an FRP molded product using this, the impregnating property of the unsaturated polyester resin serving as the matrix is improved, and the melamine resin contained and the silane coupling agent work to chemically bond the resin and the surface of the glass fiber. By doing so, characteristics such as water resistance, mechanical strength, and heat resistance can be dramatically improved. The characteristics of the melamine resin are slightly different depending on the structure and the molecular weight, but a water-soluble methylated melamine resin which is easily soluble in water is preferably used. Examples of such a resin include a methylated melamine resin alkyl-etherified with methanol, and a mixed etherified melamine resin alkyl-etherified with two types of alcohols such as methanol and butanol. Is used. The content of the melamine resin is 5-50% by weight of the solid content of the sizing agent.
And preferably 7-35% by weight.

Since sufficient properties cannot be obtained by adding a melamine resin alone, a silane coupling agent capable of reacting with a melamine resin used in combination must be chemically bonded to an unsaturated polyester resin which is usually compounded. A melamine-reactive silane coupling agent having a functional group that easily reacts with a melamine resin in combination with or without using a vinylsilane-based, acrylic silane-based, epoxysilane-based, or aminosilane-based silane coupling agent Is selectively used. Specific examples of the functional group include epoxy groups, amino groups, ureido groups, mercapto groups, chloro groups, hydroxyl groups, and silane coupling agents containing a carboxyl group.
Amino silane, ureido silane, mercapto silane and the like can be easily obtained.

The content is 0.1% of the solid content of the sizing agent.
It is 1-10% by weight, preferably 0.5-5% by weight. The amount of the melamine-reactive silane coupling agent in all the combined silane coupling agents is 10-100% by weight. The ratio of the melamine resin to the melamine-reactive silane coupling agent is used in a ratio of 10: 1-1: 10. The sizing agent containing the melamine resin and the silane coupling agent of the present invention is attached to the glass strand for FRP, but the glass strand is limited by the glass composition, the diameter of the filament, the cross-sectional shape of the filament, the number of filaments constituting the strand, and the like. However, it can be applied to any glass strand. The amount of sizing agent to be deposited is 0.
1-10.0% by weight, particularly preferably 0.5-5.0% by weight.
% By weight.

[0011]

【Example】

Example 1 0.1 kg of acetic acid is added to 80 kg of pure water to adjust the pH to 3.5. To this solution, 0.3 kg of methacrylsilane (A174, manufactured by Nippon Unicar) as a silane coupling agent is weighed and added. After sufficiently stirring and dissolving, 0.1 k of epoxy silane (A187, manufactured by Nippon Unicar) is added.
g and lightly dissolve. After completely dissolving the silane coupling agent, the melamine resin (Sumitomo Chemical,
0.5 kg of Sumimar M-30W) are metered in and dissolved in the same manner. Next, 6 kg of a pinyl acetate resin emulsion (solid content: 55%) and 1 kg of an ethylene-vinyl acetate copolymer resin emulsion (solid content: 50%) are weighed and dispersed. To this, 0.1 kg of an acetic acid activated product of a condensate of tetraethylenepentamine and stearic acid, 0.1 kg of a modified silicone oil, and 0.2 kg of lithium nitrate as an antistatic agent were sequentially added to another container. Pure water and total weight 10
Adjust to 0kg. This sizing agent was attached to a glass fiber spinning fiber bundle having a fiber diameter of 13 μm and a sizing number of 800 (270 tex) by 0.95% by weight to form a strand, and a plurality of strands were combined to form a glass roving. No fluff and no static electricity were generated when the roving was prepared, and the workability was good. While cutting this glass roving, SM
A C sheet was prepared according to the following specifications, and molded by a heating and pressing press to obtain a flat SMC molded product (thickness: 3 mm). SMC formulation: unsaturated polyester resin 80 parts Low shrinkage agent 20 parts Calcium carbonate 70 parts Aluminum hydroxide 70 parts Magnesium oxide 0.8 parts Zinc stearate 5 parts Styrene 4 parts Peroxybenzoate 1 part Glass roving (length 25 mm) 80 Department

Test method: Bending test: According to JIS R3420. Water resistance: The time until blistering occurs in boiling water. Water absorption: Measured after standing in boiling water for 1000 hours.

Example 2 A glass roving was prepared in the same manner as in Example 1 except that the silane coupling agent was changed from epoxy silane (A187) to aminosilane (A-1100, manufactured by Nippon Unicar). Further, an SMC molded product was prepared in the same manner as in Example 1, and the characteristics were evaluated. Table 1 shows the results.

Comparative Example 1 Table 1 shows the properties of the SMC molded article obtained in the same manner as in Example 1 except that the melamine resin was omitted.

Comparative Example 2 Table 1 shows the characteristics of an SMC molded article obtained in the same manner as in Example 1 except that ethoxysilane was omitted.

[0016]

According to the present invention, since a sizing agent containing a film-forming agent, a melamine resin and a melamine-reactive silane coupling agent at the same time is used as described in claim 1, excellent workability and a test shown in Table 1 are obtained. As shown in the results, it is possible to produce an SMC molded article having an extremely long blistering time and excellent water absorption.

[0017]

[Table 1]

Claims (3)

[Claims] 1. A sizing agent for glass fibers, comprising a film forming agent, a melamine resin, and a melamine resin-reactive silane coupling agent as essential components. 2. The sizing agent for glass fibers according to claim 1, wherein the compounding ratio of the melamine resin and the melamine resin-reactive silane coupling agent is from 10: 1 to 1:10. 3. The sizing agent according to claim 1, wherein the sizing agent has a solid content of 0.1%.
A glass fiber bundle having 5 to 5% by weight attached.