JPS6158409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass roving (hereinafter abbreviated as roving), which is made by bundling hundreds of glass filaments together with an adhesive, further bundling several to several dozen strands and winding them into a cylindrical shape. .

Currently, FRP products are used in large quantities in residential equipment such as septic tanks and bathtubs, fishing boats, and leisure boats, due to their light weight, good corrosion resistance, and high strength. Glass fiber products that are frequently used as reinforcement for these FRP products include glass chopped strand mats, rovings, glass roving cloth, and glass cloth. The most commonly used base material among these is roving.

Roving depends on the FRP forming method (filament winding method, drawing method, etc.).
It can be used by being impregnated with resin liquid without being cut, but it can be used by cutting it to a predetermined length and then integrating it with resin, such as by spray method, sheet molding method, liquid plate continuous molding method, etc. It is also widely used in the method of The most important property required for roving that is cut to a predetermined length for use is that it must have a good ability to unravel into individual strands after being cut (hereinafter referred to as unbundling properties). . This is because if there are parts of the roving bundle that are not unbundled, complete contact between the resin and glass fibers may be prevented, many air bubbles may be incorporated into the FRP molded product, or the glass content distribution may become extremely uneven. This is because not only the physical properties of the FRP molded product deteriorate but also the appearance of the FRP molded product deteriorates.

The reason for poor unbundling properties when cutting roving for use is that by bundling strands together and winding them into a cylindrical shape as roving,
This is because the strands come into pressure contact with each other and the surface treatment agent of the strands adheres to each other.

As a conventional technique for solving such poor unbundling properties, there is a known method of treating with a processing agent composition that has a high softening point and low stickiness and does not soften even under hot and humid conditions in the summer. However, when treated with such a treatment agent composition, the compatibility with the resin often deteriorates, and the glass fiber and resin may separate after molding the FRP product, making it impossible to obtain the desired strength, or the glass fiber portion However, there are problems in that whitening occurs, in which the paint appears white, and water resistance deteriorates, and it is extremely difficult to solve these problems.

In addition, as another conventional technique for improving the unbundling property, there is a method of lowering the tension and winding it into a soft package to reduce the contact pressure between the strands, but it is easy to deform during handling, especially If the strands are stacked in multiple stages and transported, uneven compression is applied to the package during transportation, causing the package to be compressed and deformed obliquely and not forming a cylindrical shape, which poses a problem in that the strand bundle cannot be pulled out smoothly during use.

The inventors of the present invention have conducted intensive studies to solve these problems of the prior art, and as a result, the inventors have found that a strand bundle with a bulk specific gravity of 1.3 g/cm ³ or less is wound softly under a slight tension. By uniformly compressing the glass roving in the height direction (=axial direction of the roving) to make it denser, the unbundling property when cutting the roving is poor even if the roving is left under high temperature and high humidity conditions. However, it was found that the degree of unbundling is the same as that of soft rolled roving having a bulk specific gravity of 1.3 g/cm ³ or less, and deformation is less likely to occur during multi-stage stacking and transportation, leading to the present invention.

It is not clear why the unbundling properties of the roving produced in this way do not deteriorate, but by uniformly compressing the roving to the height, the contact pressure between the strands and between the strand bundles is equalized. This seems to be due to the following.

The present invention will be specifically explained below using Examples and Comparative Examples.

Example 1 One filament was treated with a treatment agent consisting of 6% by weight of polyvinyl acetate, 0.3% by weight of surfactant, 0.2% by weight of coupling agent, 0.2% by weight of antistatic agent and 93.3% by weight of deionized water. A bundle of 12 strands with a thickness of 190 tex (unit of thickness means weight in grams per 1000 length) obtained by drying at 125℃ for 8 hours, and a small amount of By applying tension and rolling it up, the bulk specific gravity
1.5g/ ^cm3 , height 26.0cm, outer diameter 26.0cm, weight
Created roving weighing 15.6Kg. This roving was uniformly compressed using a press so that it was parallel to the floor surface from the height direction to produce a roving with a height of 24.0 cm and a bulk specific gravity of 1.25 g/cm ³ . A large number of these high-density rovings are made using the same method as above,
It was found that no deformation occurred even when stacked in three layers and transported by truck for 500 km, and that even after being left for two months and then cut and used, it had good unbundling properties and an FRP product with excellent properties was obtained.

Comparative Example 1 Bulk specific gravity 1.15 grams and height adjusted in Example 1
26.0cm glass rovings are stacked in 3 layers,
As a result of 500km truck transportation, the one on the bottom row was significantly deformed diagonally, and although the unbundling properties were good, the strand bundles became entangled when pulled out from the inside, making it practically unusable.

Comparative Example 2 Twelve strands with a thickness of 190 tex prepared by surface treatment with the same treatment agent as in Example 1 were tied together and rolled up under strong tension to give a bulk specific gravity of 1.35.
Grams/cm ³ , height 26.0cm, outer diameter 26.0cm, weight 16.0
Kg roving does not deform when stacked in three layers and transported by truck for 500 km, but the unbundling property is poor after being left for more than a week, and FRP using this roving is
The molded product had cavities and parts with low strength.

Claims (1)

[Claims] 1 High-density glass roving made by compressing glass roving with a bulk specific gravity of 1.3 g/ ^cm3 or less evenly in the height direction (axial direction).