RU2578235C2 - Method of protecting a glass surface - Google Patents

Abstract

FIELD: construction materials.

SUBSTANCE: invention relates to a technology for applying protective film on the glass surface. On the surface of the etched glass gluing film is applied heated to 50-60 °C having a thickness of 0.3-0.7 mm, and fixed them on glass by vacuum and heating in a vacuum bag for 60 minutes at a temperature of 80-90 °C. Glass surface after pickling is coated with polyurethane or polyvinyl butyral film 0.64 mm thick, heated to 50-60 °C. Vacuumisation of glass protective film is performed in a vacuum bag with a release coating on the inside at room temperature for 30-60 minutes, then the temperature was raised to 80-85 °C at a rate of 1-1.5 °C/min and held for 60 minutes. Glass work piece with protective film is stored in a vacuum bag prior to assembly of the composite material.

EFFECT: method of protecting a glass surface can significantly improve the optical characteristics of the constructional optics product while maintaining high strength of composite materials.

5 cl, 2 ex

Description

The invention relates to a technology for applying protective films to a glass surface and is a method of preserving the surface of chemically toughened glasses obtained by etching in aqueous solutions of hydrofluoric and sulfuric acids, used, for example, for the manufacture of structural optics (PPI).

A known method of protecting the surfaces of etched glasses by applying organosilicon monomers, which allows to increase the average strength of the glass from 100-200 MPa to 1500-2500 MPa (depending on the thickness of the glass), which is a consequence of maintaining the surface condition and eliminating moisture aging due to their chemical grafting to glass [Bershtein V.A., Vitman F.F., Volovets L.D. Chemical surface modification and high strength sheet glass. On Sat Mechanical and thermal properties and structure of inorganic glasses, M., 1972, p. 215-224].

The disadvantage of this method is the impossibility of combining the obtained polymer coatings with adhesive films used on an industrial scale, and the selection of special finishes (adhesive materials) is not technologically advanced.

There is also a known method of coating by air spraying varnishes with a spray gun, used in the automotive industry and allowing to apply varnish without flowing onto two surfaces [French Patent, No. FR 2563835, cl. C03C 17/32, publ. 12/12/1986].

However, the method of applying protective coatings by air spraying turned out to be unsuitable for etched glasses, since due to the action of varnish particles on the juvenile surface, the strength under centrally symmetric bending was reduced by 30-50%.

Closest to the claimed is a method of protecting the surface of etched glass from various kinds of chemical and mechanical damage by applying polyvinyl butyral varnish coatings. The most technologically advanced for creating composite materials are varnishes containing components of adhesive layers, as a rule, of various polyvinyl butyral (PVB) films of a certain concentration, which are applied to the glass blanks by irrigation [Method for manufacturing multilayer glazing. USSR copyright certificate, No. 333144, cl. С03С 27/12, declared 12/06/1967, publ. 03/21/1972] [prototype].

The fastening of protective films (ZP) on the glass surface occurs during heat treatment of glass blanks in a thermostat at a temperature of 50-150 ° C for 30-120 minutes.

The disadvantage of this method is that to obtain a protective coating of a certain thickness, which is necessary to protect the etched surface from mechanical damage during the assembly of composite materials, it requires repeated use, which leads to a significant increase in the cost of the process. And, in addition, good results in optical parameters in the IRF compositions can be obtained only if the composition of the protective varnish (for example, based on PVB film) and the bonding material - PVB film are identical.

In this case, the protective varnish is completely dissolved in the adhesive layer and there are no optical defects. However, modern PPI compositions include several different bonding materials, as consist of several functional parts. The outer and rear glass, as a rule, are glued on both sides to the etched glass or block using elastic polyurethane (PU) adhesive films. In this case, a protective PVB varnish applied to the etched surface of the power unit does not completely dissolve in the PU material.

As a result, two surfaces are formed, connected by adhesive bonds, but having different physical properties, which is the cause of optical distortions of the finished product. It is practically impossible to coat one side of the power glass with liquid varnish based on PVB material and the other based on PU varnish without watering each varnish onto the opposite surface, and removing the stained varnish from the opposite etched surface mechanically causes a decrease in the strength of the etched glass.

Flowing to the opposite side can be avoided by gluing the end of the boundary film and applying the calculated amount of varnish (dosed watering) to the surface.

This method has been recommended for applying a protective coating to flat glass blanks. In this case, the flow of varnish to the other side can be avoided, but this method has not received industrial development due to the complexity of the uniform distribution of the protective coating.

It should also be noted that the replacement of PVB varnishes with varnishes containing components of a polyurethane film (PU) was not possible because of the high volatility of the solvents of the PU film, the evaporation of which led to a change in the viscosity of the varnish during irrigation and the uneven distribution of this coating over the surface oversized glass blanks.

The objective of the invention is to increase the optical characteristics of products of structural optics based on etched glasses, as well as reducing their cost while maintaining the strength of hardened glass blanks.

The problem is solved as follows.

An adhesive film of 0.3-0.7 mm thick, of the same grade as the adhesive material in the composition, facing this side of the glass, which is heated in an thermostat to 50-60 ° C, is placed on a glass backing coated with a release film. dried etched glass is placed on the heated adhesive film, preventing glass from moving relative to the film.

On top, another gluing film is applied, 0.3-0.7 mm thick, of the same grade as the adhesive material in the composition, facing this side of the glass, heated to 50-60 ° C, and a release film on it.

The collected composite material is subjected to evacuation at a pressure of P = - (0.6-0.8) bar in special vacuum bags for 30-90 minutes, then the temperature is raised to 80-90 ° C and kept in a thermostat for 30-90 minutes .

The material is cooled to room temperature spontaneously or automatically. Glass blanks are stored in a vacuum bag until the product is packaged.

Example 1

According to the traditional method, to protect the etched surface of the glass, a varnish of a certain concentration is used, made by dissolving the bonding film in ethanol, the application of which is repeated three times. Coated glass is first dried in the application chamber, then baked in a thermostat and transferred to the assembly area, and the shelf life of the glass blanks is limited. Next, the outer glass is glued with a polyurethane film.

With such conservation of the etched surface of the glass, the average strength of satellite samples with central symmetric bending (CSI) is from 13 00 to 1900 MPa, with a minimum strength of 300 to 600 MPa. After pressing the composite material when viewing at an angle, the appearance of optical defects (ripples) was noted.

According to our proposed method, the dried etched glass is placed on a substrate glass coated with release and PU film (0.38 mm thick) heated to (53 ± 2) ° С, then it is coated on top with similar films and everything is placed in a vacuum bag. Processing in a vacuum is carried out first at room temperature for 40-50 minutes, then the temperature is raised to 85 ° C and held for 60 minutes. Glass cooling is carried out spontaneously. Next, glass billet as a power window is used in the assembly of the pentaplex. The strength in the case of the central digital center on manufactured satellite samples was 1760 (1000-2100) MPa. Optical distortion on the product after pressing was not observed.

Example 2

The dried etched glass is placed on a substrate glass coated with a PVB film (0.64 mm thick) heated to (55 ± 2) ° C, then it is coated on top with similar films and everything is placed in a vacuum bag. Processing in a vacuum is carried out first at room temperature for 40-50 minutes, then the temperature is raised to 87 ° C and held for 60 minutes. Glass cooling is spontaneous. Next, glass billet as a power window is used in the assembly of the pentaplex. The strength in the case of SSC on manufactured satellite samples was 1390 (780-1690) MPa. Optical distortion on the product after pressing was not observed.

It should be noted that for preservation of etched glass surfaces on both sides, protection variations are possible both with two films of the same chemical composition and films with different adhesion grafting mechanisms ↔ glass.

The proposed method of surface protection eliminates the process of preparing PVB varnishes of strictly specified viscosity and temperature, application processes, drying of the protective coating in special chambers and, as a result, reduces the cost of electricity and labor.

In this case, the use of an expensive solvent of PVB film (rectified ethyl alcohol "Extra" GOST 28546 - 90, consumption when applying a protective coating - 3 l / m ² ) is excluded, thereby reducing the cost of manufacturing an IRF, and most importantly, the optical characteristics are significantly improved while maintaining high strength values of composite materials.

Information sources

1. Bershtein V.A., Vitman F.F., Volovets L.D. Chemical surface modification and high strength sheet glass. On Sat Mechanical and thermal properties and structure of inorganic glasses. M. 1972, p. 215-224.

2. French Patent No. 8406783, C03C 17/32, 1985.

3. Copyright certificate. No. 333144, С03с 27/12, 1972.

Claims (5)

1. A method of protecting a glass surface hardened by chemical etching in aqueous solutions containing hydrofluoric acid by applying a polymer coating to its surface, heating, holding and then cooling to room temperature, characterized in that the polymer coating is applied by applying heated to 50- 60 ° C of polymer films on the surface of etched glasses, their subsequent evacuation at room temperature, heating under vacuum to a temperature of 80-90 ° C, holding at this temperature Ur for 30-60 minutes, then cooling to room temperature, further storage in a vacuum. 2. The method according to p. 1, characterized in that they use a polyurethane or polyvinyl butyral film or a combination thereof. 3. The method according to any one of paragraphs. 1 or 2, characterized in that the heating in vacuum is carried out at a temperature of 85-90 ° C. 4. The method according to any one of paragraphs. 1-3, characterized in that the evacuation of the glass after applying the protective films is carried out in vacuum bags with an internal release coating at room temperature for 30-60 minutes. 5. The method according to any one of paragraphs. 1-4, characterized in that the glass with a polymer film is stored in a vacuum bag.