CS275864B6 - A method for producing glass microfibres - Google Patents

Abstract

Microscales, especially those with a thickness of 2 to 6 μm, are prepared from thin-walled glass foil obtained from a glass flask, which is heated evenly throughout and then blown rapidly with air pressure until it breaks into fragments, which can be processed by crushing or grinding as needed. Glass microscales are intended as an additive to anti-corrosion coatings, a filler for plastics, for the production of glass paper, etc.

Description

The invention relates to a process for the production of glass microflakes, in particular microflakes with a thickness of 2 to 6 .mu.m. The microflakes are obtained from a thin-walled glass foil, after the disintegration of which the fragments obtained are subsequently treated by crushing or grinding to the desired size.

Various methods for the production of glass flakes or scales are known, either by forming suitable semi-finished products, e.g. flat glass, glass cylinders, tubes, etc., or by direct melt forming.

The method of production of glass flakes by transforming shaped glass is given, for example, in the Czechoslovak author's certificate No. 113 454. Glass flakes are obtained by crushing the foil, in particular by means of rollers. The film is formed by drawing from a sheet of glass heated to a temperature of 1,100 to 1,300 ° C by multi-stage drawing at a speed of 5 to 50 m.s '·' ·. In this way, a film with a thickness of up to 20 [mu] m is obtained.

It can be assumed that during several stages of drawing, the thickness of the glass sheet gradually decreases, and thus its area increases, which can cause difficulties both in realizing the requirement of uniform heating for the next stage of drawing and especially Large differences in the thickness of the scales limit their use.

A one-step method for producing glass flakes directly from glass is disclosed in Japanese Patent Application No. 21,533-84. A continuous stream of glass is fed to the medium. part of a horizontally rotating disk, whereby the glass is dispersed around the circumference of the disk in the form of a thin film which is further drawn by the action of flowing air which is blown from below the thin film in the drawing direction so as to draw and harden the thin layer. During curing, the thin layer splits into small pieces to form flakes, which are collected by a stream of air. The circumferential part of the disk is made of graphite and an inert gas is applied in the space around the circumference of the disk in the production process.

The advantage of this solution is continuous single-stage production and probably a large production capacity.

With the centrifugal method of forming the film, it is probably difficult to obtain a glass film with a thickness below 10 .mu.m, which limits its subsequent application. Technological adjustment of production equipment is probably extremely demanding to maintain constant parameters, especially temperature. .

These disadvantages are eliminated or substantially reduced in the process for the production of glass microblasts, in particular 2 to 6 .mu.m thick from a thin-walled film according to the invention, the essence of which is that the thin-walled glass film is obtained from a glass flask which is uniformly heated throughout the mass. after complete warm-up, it blows violently with compressed air until it disintegrates.

The advantage of this solution is the simplicity of the method and the equipment used in one-stage and two-stage production, eg from tubes. This procedure enables the production of extremely thin glass microblasts, with a narrow dispersion of thickness, which can be used in thin layers of paints, where it fulfills the function of anticorrosion, or filling plastics, which increases strength, or for the production of facade materials in construction, or as the main component in the production of glass paper, etc.

An exemplary embodiment of the method is described below on a specific embodiment of the production of microblasts from glass tubes on a multi-position carousel machine.

First, the glass tube is inserted vertically into the upper spindle of the multi-spindle carousel machine and clamped on impact with the stop bridge. The upper end of the tube is connected to compressed air. In the lower part of the tube, where it is necessary to create a constriction, the tube is heated while simultaneously clamping the open lower end into the lower spindle. After sufficient warm-up, the lower spindle moves downwards, the tube is stretched and narrowed at the heated point. The upper part of the constriction is further heated, while at the same time the lower part is cooled.

CS 275864 B 6 2

Subsequently, the lower spindle is moved downwards, the tube is interrupted at a constricted point and at the same time the bottom of the future flask is formed, which is cooled to prevent deformation. The closed end of the tube is clamped by the lower spindle and at the same time the glass tube is heated at the point of future narrowing of the neck of the flask. The deflection of the lower spindle narrows at the point of heating and thus creates a neck of the flask, which is subsequently cooled to compensate for the temperature gradient in the flask. While cooling the flask neck, the lower spindle is released and moved down. With a special burner, the entire body of the glass flask is evenly heated in several other positions. After complete heating, the flask is blown with compressed air until it ruptures and forms irregular pieces or fragments of glass foil of the required thickness, which are discharged outside the machine into the hopper by means of a suction device. The rest of the glass tube clamped in the upper spindle is ignited after the flask has been blown, and the whole working cycle is repeated. .

Fragments or pieces of glass foil are crushed or ground as required.

Claims (1)

PATENT CLAIMS Process for the production of glass microblasts, in particular 2 to 6 .mu.m thick, from thin-walled. glass foil, after the disintegration of which the obtained fragments are subsequently adjusted by crushing or grinding to the desired size, characterized in that the thin-walled glass foil is obtained from a glass flask which is uniformly heated throughout the mass and after perfect heating is blown to disintegrate it into fragments.