DE1596826C3 - Process for the production of iridescent glasses with underglazing - Google Patents

Description

The invention relates to a method of manufacture - of iridescent glasses, in which a glass body with a silver salt and a sublimable metal compound is treated with the involvement of a reduction.

From DT-PS 1 22 897 it has become known to produce matt or glossy iridescence on glass objects in that a conventionally pre-processed glass object is pre-colored with a metal, ie by metals such as gold, silver, copper, antimony, etc. or by metal oxides colored glass melt is provided, then heated and subsequently the iridescence-causing vapors of tin, strontium ^1, barium salts, inter alia, is exposed in the usual manner. It is particularly pointed out there that a reduction is effected during the heating.

While in these methods the iridescence on the glass objects, i. H. generated on their surface is, the invention has set itself the task of a reliable iridescence by means of a wafer-thin metal layer inside the vitreous in the form of iridescent bubbles. The application of another Glass layer on the iridescence is not possible in the aforementioned known method because when piercing over the iridescence layer is destroyed.

The object of the invention is thereby achieved; that to achieve an underglazing the glass surface roughened before treatment and pierced after treatment.

As a result of the roughening of the surface of the vitreous body, indentations are created in which, as a result Capillary action, the reduced metal accumulates strongly, as described in DT-PS 5 05 041 above. Surprisingly, it was found that the metal particles located in the depressions when trapped are not adversely affected by the high temperatures occurring, as is the case without roughening the case is. Since the subliming metal compound also collects in the depressions, will these are also protected from adverse effects by the cladding glass.

In the method of the invention, the reduction is preferably carried out by immersion in a Reduk tion agent, especially in sawdust. This is supported by charred residues in the depressions through gasification in the case of piercing, the preservation of the reduced metal, d. H. by enriching silver and reducing agents the metal deposits are more permanent than a metal layer, which is evenly on a smooth Glass surface sits.

When the vial is then pierced with liquid glass, all of the raised surface areas connect with this glass, with the metal on them. compound burns. This creates on these Make a veil of bubbles and a slight discoloration. Due to its toughness, however, the glass penetrates not into the depressions, and the gasifying residues in them cannot escape. she but also do not come into direct contact with the liquid glass, so that they do not burn, but sublimate due to the thermal radiation and form bubbles in the soft piercing glass. This clearly visible bubbles do not show any iridescence, but only when the vitreous humor is in the bubble area When the solidification temperature is reached, a silky, matt iridescence of the bladder walls suddenly appears the precipitate of the cooled sublimate.

When piercing over the parison, the sublimable metal compounds thus fulfill a double task: They protect the wafer-thin metal layer against the high temperature of the pierced glass, and on the other hand, due to their sublimation, they form bubbles on the surface of the metal layer and beat then settles on the surface of the bubbles as the glass cools. This results in novel Iridescence effects as a result of the resulting mother-of-pearl-like matt gas bubbles that penetrate the glass mass are built in. The effect of this iridescence is particularly noticeable when the substrate is in contact with the the iridescence and the areas bearing gas bubbles are dark in color.

The metal sulfides, chlorides or arsenic oxide known per se are used as sublimable metal compounds into consideration. Tin chloride is preferably used.

In detail, the process can be carried out in the following way:

The surface of the hot parison is roughened by placing it in a rough glass mold or briefly quench the hot glass in water.

Instead, the parison can also be sprinkled with glass powder or glass crumbs or with a small amount Foam glass can be coated. Then the still hot glass bowl is coated with silver halide, e.g. B. silver chloride, sprinkled, which melts due to the inherent heat of the glass, so that liquid silver chloride droplets are formed, which adhere to the glass, especially in its capillary depressions or the like. Here the glass takes a yellow color. By "immersion in sawdust or another reducing agent in the absence of air During half a minute to a full minute or by treatment with reducing gases, the silver chloride becomes reduced to metallic silver; the sawdust burns up. Then it is applied to the vitreous Tin chloride evaporated by introducing it into a container in which the tin chloride is evaporated. A white flaky coating forms. If the parcel prepared in this way then is pierced with liquid glass, that sublimates

Tin chloride with the formation of numerous bubbles, and when the glass cools, the sublimate becomes visible the surface of the bubbles. This creates matted and iridescent bubbles in the glass mass.

Claims (4)

Patent claims: 1. Process for the production of iridescent glasses, in which a glass body with silver salt and with a sublimable metal compound with the inclusion of a. Reduction is treated, characterized in that the glass surface is used to achieve underglazing roughened before treatment and pierced after treatment. 2. The method according to claim 1, characterized in that the reduction by immersion in a reducing agent is made. 3. The method according to claim 2, characterized in that sawdust is used as the reducing agent will. 4. The method according to any one of claims 1 to 3, characterized in that the silver salt is silver chloride and tin chloride can be used as the sublimable metal compound.