JPS636509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment agent for glass fibers that can provide glass fibers with a high reinforcing effect and high cohesiveness, and a method for preparing the same.

Currently, glass fiber products are widely used as reinforcing materials for various reinforced plastic products. Glass fiber products are usually produced by pulling out a large number of glass filaments from a bushing with many nozzle holes installed at the bottom of a glass melting forefurnace.
Immediately after that, a film forming agent, a coupling agent,
It is manufactured by surface-treating each glass filament with a treatment agent containing a lubricant, an antistatic agent, etc., bundling it into several bundles with a guide, winding them up, and heating and drying the rolled up products.

The performance required of a surface treatment agent for glass fibers is that the treatment agent composition has high adhesion to glass fibers, can produce highly cohesive glass fiber products, and has high adhesion between the treatment agent film and the resin matrix. Among these are the ability to provide strong and high-strength glass fiber reinforced plastic products (hereinafter referred to as FRP products).

However, there is a limit to the reinforcing effect of glass fibers that have been surface-treated with a treatment agent that uses polyvinyl acetate resin, which is currently widely used as a film-forming agent in surface treatment agents for glass fibers, as a film-forming agent. This glass fiber reinforced
This tendency is large in FRP products, especially FRP molded products using sheet molding compound (hereinafter referred to as SMC) and bulk molding compound (hereinafter referred to as BMC), and it is difficult to obtain sufficient FRP strength to meet market demands. ,
The problem is that it is difficult.

As a conventional technique for manufacturing high-strength FRP products, a method of increasing the glass fiber content of FRP products is known, but in this method, for example, SMC
In such cases, there are many problems that lead to a decline in cost competitiveness, such as increases in equipment costs, decreases in work efficiency, and increases in material costs. In addition, with the aim of providing high-strength FRP products, research has been conducted on surface treatment agents for glass fibers, and polyester resins, epoxy resins, or polyurethane resins are used as the film forming agent component of the surface treatment agents. It is known that by using polyvinyl acetate resin, glass fiber products with a higher reinforcing effect can be obtained than in the case of polyvinyl acetate resin. It has the problem of being expensive.

In order to solve the problems of the prior art described above and obtain a glass fiber product with a high reinforcing effect, the present inventors have developed a surface treatment using a relatively inexpensive polyvinyl acetate resin as the main component of the film forming agent. As a result of extensive research on the agent, we have developed a glass fiber surface treated with a surface treatment agent that uses a crosslinking reaction product of a polyvinyl acetate resin with reactive functional groups and a silane coupling agent as a film-forming agent component. It was discovered that the product has an extremely high reinforcing effect, leading to the present invention.

As the polyvinyl acetate resin having a reactive functional group to be incorporated into the surface treatment agent of the present invention, one having a functional group such as a silanol group, a glycidyl group, or a methylol group is preferable.

As the silane coupling agent which is a crosslinking agent to be incorporated into the surface treatment agent of the present invention, acrylic silane, vinyl silane, amino silane, epoxy silane, peroxy silane, mercapto silane, etc. are preferable.

The content of reactive functional groups in the polyvinyl acetate resin having reactive functional groups is preferably in the range of 0.5 to 10% by weight, and the blending ratio of the silane coupling agent, which is a crosslinking agent, is The amount is desirably in the range of 1 to 15% by weight based on the blended amount of the vinyl acetate resin.

When a polyvinyl acetate resin having a silanol group as a functional group is used as a film forming agent for a treatment agent, acrylic silane and vinyl silane are particularly preferred as crosslinking agents, and polyvinyl acetate resins having a glycidyl group or a methylol group as a functional group are particularly preferred as crosslinking agents. When the resin is used as a film forming agent for a treatment agent, aminosilane is particularly preferred as the crosslinking agent. Furthermore, when a silane coupling agent is blended into an aqueous dispersion of polyvinyl acetate resin having a reactive functional group and a crosslinking reaction is carried out while stirring, the thinner the concentration of the aqueous dispersion is, the more the crosslinking reaction is Since it takes a long time and the preparation efficiency of the surface treatment agent decreases, in order to complete the crosslinking reaction within 1 to 6 hours, the concentration of the aqueous dispersion must be set to 20% by weight or more in terms of solid content. There is a need to.

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

Example 1 (1) Preparation of surface treatment agent 12 parts by weight of an aqueous dispersion of polyvinyl acetate resin having a silanol group as a functional group (solid content = 50
%) in a container, 0.6 parts by weight of r-methacryloxypropyltrimethoxysilane (solid content = 80%) was gradually added while stirring, and the crosslinking reaction was carried out at room temperature for 3 hours. Then put it in a separate container
Take 57 parts by weight of deionized water, add an appropriate amount of acetic acid to adjust the pH to a range of 3.5-4.0, add 0.1 parts by weight of r-methacryloxypropyltrimethoxysilane and 1.8 parts by weight of cationic surfactant. Add and stir thoroughly for 20 minutes. When the preparation is completed, mix the two types of blended liquids and stir thoroughly.
Further, 27.7 parts by weight of deionized water is added as residual water and thoroughly stirred to prepare a surface treatment agent.

(2) Preparation of glass chopped strands and SMC Immediately after drawing out the molten glass from a platinum bushing with 800 nozzle holes, the surface treatment agent prepared in (1) was applied to the glass filament using an application device, and 800 strands were prepared. After winding the glass filaments into two bundles, they were heated and dried at 130°C for 9 hours to prepare a glass strand roll. The glass strand is pulled out from the glass strand roll thus obtained and cut into 2.5 cm pieces.
This glass chopped strand with a cut length of 2.5 cm was mixed with a polyester resin compound (60 parts by weight of unsaturated polyester resin, 40 parts by weight of low shrinkage agent, 150 parts by weight of calcium carbonate, 1 part by weight of hardening agent, 4 parts by weight of lubricant). 0.5 parts by weight of a thickener) is evenly dispersed on a coated polyester film, the polyester resin composition is evenly poured onto it, and then a polyester film is further placed on top of the polyester film. After covering, it is degassed through a rolling roll and stored at 50°C for 12 hours to prepare SMC with a glass fiber content of 30%.

(3) Molding of SMC molded product (FRP plate) and its mechanical properties Using the SMC obtained in ( ² ), the thickness was A 3mm thick FRP board was molded. this
As a result of measuring the mechanical properties of the FRP board, the tensile strength was 7.1 Kg/mm ² , the bending strength was 19.8 Kg/mm ² , and the shear ruby impact strength was 68.0 Kg·cm/cm ² .

In contrast, using conventional glass chopped strands obtained by surface treatment with a surface treatment agent containing a general polyvinyl acetate resin that does not have conventional reactive functional groups as a film forming agent, SMC was prepared under exactly the same conditions as in Example 1, and an FRP plate was formed and its mechanical properties were measured. As a result, the tensile strength was 5.3 Kg/cm ² , the bending strength was 15.8 Kg/mm ^{2 , and the Sialby impact strength was 5.3 Kg/cm 2} . 51.6Kg・
cm/cm ² and glass chopped strands surface-treated with the surface treatment agent of the present invention.
The strength was low.

Example 2 (1) Preparation of surface treatment agent 11.4 parts by weight of an aqueous dispersion of polyvinyl acetate resin having a glycidyl group as a functional group (solid content =
55%) in a container and add 0.6 parts by weight of r-p minopropyltriethoxysilane (solid content = 30%).
was gradually added while stirring, and the crosslinking reaction was carried out at room temperature for 3 hours. After that, take 57 parts by weight of deionized water in a separate container, add an appropriate amount of acetic acid, and adjust the pH.
was adjusted to a range of 3.5 to 4.0, and 0.25 parts by weight of r-
Add methacryloxypropyltrimethoxysilane, 1.8 parts by weight of a cationic surfactant, and 0.25 parts by weight of lithium chloride, and stir thoroughly for 20 minutes. When the preparation is completed, mix the above two types of blended liquids, stir thoroughly, and add 28.7% as residual water.
A surface treatment agent is prepared by adding parts by weight of deionized water and stirring thoroughly.

(2) Preparation of glass chopped strands and SMC Glass chopped strands and SMC are prepared under exactly the same conditions as in Example 11.

(3) Molding of SMC molded product (FRP board) and its mechanical properties Using the SMC adjusted in (2), an FRP board was molded under exactly the same conditions as in Example 1, and its mechanical properties were measured. Tensile strength is 7.3Kg/ ^mm2 ,
The bending strength is 20.1Kg/mm ² and the Shyalby impact strength is
It was found to be extremely high at 70.3Kg・cm/cm ² .

For comparison, an aqueous dispersion of polyvinyl acetate resin having a glycidyl group as a functional group used in Example 2 was used, and r-aminopropyltriethoxysilane was prepared in exactly the same formulation as in Example 2 without crosslinking. Glass chips obtained by surface treatment with a prepared surface treatment agent (prepared by adding deionized water so that the concentration of polyvinyl acetate resin aqueous dispersion is 20% by weight or less, and then adding a silane coupling agent). SMC was prepared under exactly the same conditions as in Example 2 using the pud strands. FRP
As a result of forming a plate and measuring its mechanical properties,
Tensile strength is 5.5Kg/ ^mm2 , bending strength is 16.3Kg/
mm ² and Shalby impact strength of 53.3 Kg·cm/cm ² , which is extremely lower than when using glass chopped strands surface-treated with the surface treatment agent of the present invention.

Claims (1)

[Scope of Claims] 1. A surface treatment agent for glass fibers using a reaction product obtained by subjecting a polyvinyl acetate resin having a reactive functional group to a crosslinking reaction with a silane coupling agent as a film forming agent. 2. The surface treatment agent for glass fibers according to claim 1, wherein the reactive functional group is a silanol group, and the silane coupling agent is acrylic silane or vinyl silane. 3. The surface treatment agent for glass fibers according to claim 1, wherein the reactive functional group is a glycidyl group and the silane coupling agent is aminosilane. 4. The surface treatment agent for glass fibers according to claim 1, wherein the reactive functional group is a methylol group and the silane coupling agent is aminosilane. 5 Add a silane coupling agent to an aqueous dispersion of a polyvinyl acetate resin having a reactive functional group with a solid content of 20% or more, mix thoroughly to carry out a crosslinking reaction, and then add this crosslinking reaction product. A method for preparing a surface treatment agent for glass fibers, which is used as a film forming agent to prepare a treatment agent having a predetermined composition.