JPH02232611A - Glass fiber - Google Patents

Abstract

PURPOSE:To obtain a glass fiber having a coating structure which is excellent in heat resistance by forming the outermost layer of a coating layer of ladder type silicone. CONSTITUTION:The outermost layer 3 of the coating layer has the structure coated with the ladder type silicone and the ladder type silicone has generally such a structure as expressed by formula I. (In the formula X, Y denote a functional group, such as alkyl group or phenyl group; R denotes hydrogen, additive group, such as alkyl group.) The org. part, such as alkyl group, phenyl group or alkoxy group of the ladder type silicone induces a thermal decomposition at a high temp. but the remaining silica parts remain and can maintain the shape. The contact of the coating layer consisting of a heat resistant resin or metal existing therein with oxygen is, therefore, averted even at a high temp. The glass fiber having the coating structure which is high in the heat resistance is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to glass fibers used at high temperatures, and particularly to the structure of glass fibers with excellent heat resistance. [Prior art] So-called bare fibers drawn from a glass base material (preform) generally have small diameters and low mechanical strength, and scratches on the fiber surface are likely to grow due to the influence of dust. For this reason, it is common practice to coat the outer periphery with a resin or the like to form a protective layer. In particular, in the case of glass fibers used at high temperatures of several hundred degrees Celsius, it is necessary to use a coating material with excellent heat resistance.
Conventionally, silicone resins, polyimide resins, or metals such as aluminum, which are resins with relatively excellent heat resistance, have been used as coating materials for this type of heat-resistant glass fiber. [Problems to be Solved by the Invention] However, conventional coating materials of this type suffer from severe damage when used at high temperatures of 500°C or higher, and cannot adequately fulfill their role as a protective layer. Ta. In the case of silicone resins and polyimide resins, decomposition reactions occur at such temperatures, resulting in a significant weight loss. Additionally, in the case of metal layers, high-temperature oxidation causes corrosion of the metal, resulting in significant rust. An object of the present invention is to provide a glass fiber having a coating structure that suppresses disadvantages such as weight loss of resin and rusting of metal even in such high-temperature ring tombs, and has excellent heat resistance. [Means for Solving the Problems] In order to solve the above conventional problems, the present invention provides a glass fiber having at least two or more coating layers, in which the outermost layer of the coating layer is made of ladder-type silicon. The present invention provides a glass fiber with the following characteristics. In the present invention, a particularly preferred embodiment of the glass fiber is characterized in that the inner layer of the two or more coating layers is made of a heat-resistant resin such as a polyimide resin, a silicone resin, or a fluororesin, or a metal.

FIG. I is a sectional view of a specific example of the present invention, in which 1 is a glass fiber, 2 is a coating layer (inner layer) made of a heat-resistant resin,
3 shows the coating layer made of ladder-type silicone. In this example, the number of inner layers is one, but the number is not limited to this. FIG. 2 is a sectional view of another embodiment of the invention, in which a layer 4 made of metal is provided as an inner layer. In the above example, the inner layer is one layer, but it is not limited to this. [Function] Since the glass fiber of the present invention has a structure in which the outermost layer of the coating layer is covered with ladder-type silicone, contact between the heat-resistant resin or metal of the inner coating layer and oxygen can be prevented. Therefore, thermal decomposition reactions of heat-resistant resins and corrosion caused by high-temperature oxidation of metals can be suppressed. The reason for this is explained below. The ladder-type silicone according to the present invention generally has a structure as shown in the following model structural formula (Il). (R represents a functional group such as hydrogen or an alkyl group.) At high temperatures, organic moieties such as alkyl groups, phenyl groups, and alkoxy groups in this ladder silicone undergo thermal decomposition, but the remaining The silica portion of the ladder remains and can maintain its shape. Therefore, even at high temperatures, contact of oxygen with the coating layer made of heat-resistant resin or metal inside the ladder can be avoided. The coating thickness of the mold silicone is preferably about 0.1-107j1, and if it is less than this range, the above effects cannot be achieved,
Furthermore, if the thickness exceeds this range, it becomes difficult to form a uniform coating. Ladder type silicone coating is done by dissolving the ladder type silicone oligomer in a solvent such as alcohol or xylene, placing it in a die, applying it to the glass immediately after drawing, and then passing it through a heating furnace to evaporate the solvent and at the same time cause a condensation reaction. By means of hardening by causing .

In the present invention, the heat-resistant resin coated on the glass fiber as an inner layer includes, for example, polyimide resin, silicone resin, fluororesin, etc., and the material for the metal layer is comparatively aluminum, copper, nickel, indium, etc. It is preferred because it melts at low temperatures and is easy to apply to fibers. There is no particular restriction on the calendar number of these inner layers as long as it is 1 or more,
Generally, there are 1 to 3 layers. The heat-resistant resin layer coating is
This is commonly used as a means of forming a coating on this type of glass fiber. The glass fiber that has just been drawn is passed through a die filled with uncured resin to coat it with resin, and then passed through a heating furnace to harden the resin. Alternatively, a method such as applying a thermoplastic resin using an extruder may be used.

The metal coating can be formed by, for example, the Disob method in which a fiber is passed through a metal molten at high temperature to form a coating layer, or the CVD method in which a coating layer is formed by a chemical reaction in a gas phase. The glass fiber (bare glass fiber) of the present invention is not particularly limited in its composition, and may be made of various glasses such as quartz glass, alkali glass, and borosilicate glass. Hereinafter, details of the present invention will be specifically explained in Examples.

〔Example〕

Example 1 A glass fiber of the present invention having the structure shown in FIG. 1 was manufactured. 1
The glass fiber is made from a quartz glass base material with an outer diameter of 1
Immediately after drawing, the fiber was drawn into a 25-mm fiber, passed through a die filled with polyimide resin, and then cured in a heating furnace to be coated with a polyimide resin with a crotch thickness of 15 μm. ',R
=X=Y=-Ch) and then passed through a heating furnace to harden to form a ladder-type silicone outermost layer with a crotch thickness of 7p. The glass fiber of the present invention obtained above was cut to a length of 3 m, and placed in an electric furnace at 500°C for 24 hours.
I left it for a while. Next, when it was taken out of the furnace and its shape was inspected, it was found that the coating maintained its initial shape, and its tensile strength was measured at a gauge line distance of 300 m and a tensile speed of 100 mm/m.
When evaluated using f, the weight was 6 kg, which is equivalent to the strength when left at 500°C. Comparison 1P1l A comparative glass fiber of 3 m manufactured in exactly the same manner as in Example 1 except that the structure was coated only with polyimide resin having a film thickness of 15/J without coating with ladder-type silicone was heated to 500° C. in the same manner as in Example 1. When it was left in an electric furnace for 24 hours, the polyimide resin coating completely decomposed and disappeared.

Example 2 A glass fiber of the present invention having the structure shown in FIG. 2 was manufactured. l
The glass fiber is made from a quartz glass base material with an outer diameter of 1
A 25/7I1 fiber was drawn, and the fiber was passed through molten aluminum and coated with aluminum to form a coating layer with a thickness of 15p. After the temperature had cooled down sufficiently, ladder-type silicone was applied in the same manner and then cured to form the outermost layer of ladder-type silicone with a film thickness of 7p. The glass fiber of the present invention obtained above was cut into a length of 3 m.
It was cut out and left in an electric furnace at 500°C for 24 hours. After being left alone, the glass fiber retained its shape and there was no change in appearance. Comparative Example 2 Regarding a comparative glass fiber of 3 m manufactured in exactly the same manner as in Example 1 except that the structure was coated with an aluminum layer of 15 ta thick without coating with ladder-type silicone,
When it was left in an electric furnace at 500°C for 24 hours in the same manner as in Example 1, rust had grown all over the surface of the aluminum, starting from white aluminum oxide caused by high-temperature oxidation of aluminum. In Example 2, an example was shown in which aluminum was used as the metal coating, but the same effect as in Example 2 was obtained even in the case of an inner layer of other metals such as copper, nickel, and indium. According to experiments conducted by the present inventors, it has been found that the glass fiber of the present invention can be used at temperatures of 600 to 800°C. As is clear from the results of the above Examples and Comparative Examples, the glass fiber of the present invention can prevent the oxidation reaction of the internal coating layer by using ladder-type silicone as the outermost layer, thereby providing a highly heat-resistant coating. This realizes a glass fiber with a structure. [Effects of the Invention] As explained above, the glass fiber of the present invention has a structure in which the outermost layer of the coating layer is covered with ladder-type silicone. Contact can be avoided, corrosion caused by thermal decomposition reactions of heat-resistant resins and high-temperature oxidation of metals can be suppressed, and heat resistance and strength can be improved compared to conventional methods.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views showing specific examples of the present invention. FIG. 1 shows an example in which the inner layer is made of heat-resistant resin, and FIG. 2 shows an example in which the inner layer is made of metal.

Claims (3)

[Claims] (1) A glass fiber having at least two or more coating layers, wherein the outermost layer of the coating layer is made of ladder-type silicon. (2) The glass fiber according to claim 1, wherein the inner layer of the two or more coating layers is made of a heat-resistant resin such as a polyimide resin, a silicone resin, or a fluorine resin. (3) The glass fiber according to claim 1, wherein an inner layer of the two or more coating layers is made of metal.