GB2118928A

GB2118928A - Enamelling process

Info

Publication number: GB2118928A
Application number: GB08211567A
Authority: GB
Inventors: Geoffrey Cooke; Bruce Alfred Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-21
Filing date: 1982-04-21
Publication date: 1983-11-09

Abstract

A vitreous enamelling process in which an aqueous enamelling composition containing glass and/or metal particles is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base, wherein a water-soluble alkyl cellulose is included in the composition as a suspending agent for the particles.

Description

SPECIFICATION Enamelling process This invention concerns vitreous enamelling processes in which an enamelling composition is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base.

When the substrate is glass, the composition and the glaze may contain particles (powder or flakes) of a metal such as gold or silver instead of or in addition to particles of glass. Because of the nature of the composition, and particularly the presence of glass, firing is carried out rapidly (perhaps for 2 or 3 minutes) at a temperature of 500-1 1000C.

According to the invention, a water-soluble alkyl cellulose is used as a suspending agent for glass and/or metal particles in an aqueous vitreous enamelling composition of the type just described. Water-soluble alkyl celluloses have a long shelf life, can be premixed with glass or metal particles, can be used with tap water, can be used at various concentrations to give the desired viscosity, can be fired wet, do not bloom the glass or leave a carbonaceous residue and can be used with flame heating as well as furnace heating.

The preferred alkyl celluloses are methyl cellulose with a degree of substitution of between 0.7-2.6 ethyl cellulose with a degree of substitution of between 0.5-1.3 Isopropyl cellulose with a degree of substitution of between 0.4-0.9.

Example 1 A vitreous enamelling composition was made up as follows:- Glass particles (100 mesh) 77.8% Methyl cellulose (Degree of substitution 1.6) 0.3% Water 21.9% This composition was used for laying on with a palate knife, or similar, onto a 14 carat gold base to provide a decorative effect and the whole was fired in a furnace at 800 deg. C. for approximately 2 minutes. A fine transparent glaze was obtained.

Example 2 This vitreous enamelling process was repeated except that the composition of the mixture was altered to that below, in order that glass enamel could be sprayed by compressed air spraygun onto a silver plate.

Composition Glass particles (400 mesh) 56.1% Methyl cellulose (Degree of substitution=1.6) 0.3% Water 43.6% This plate was allowed to dry in air at room temperature and fired in a furnace at 750 deg. C.

for approximately 2 minutes.

Again a fine transparent glaze was obtained.

Example 3 It was required to adhere thin gold and silver paillons and shims onto a glass on gold surface in order to sandwich the gold and silver pieces between the base glass and further clear glass overlay. This was achieved by making a composition of binder containing 0.1% methyl cellulose (degree of substitution=1.6) in water w/v. The gold and silver paillons and shims were laid onto the surface of the base glass which had been precoated with binder immediately before laying. After drying the whole was refired at 750 deg. C. for approximately 1 EF minutes, cooled and overlay glass (composition as in Example 1) was administered and fired as in Example 1.

A clear glaze was produced which had embedded in its interior the gold and silver metal pieces as they had been placed with no movement or blemish.

The ratio of composition of binder: water: glass may be altered to facilitate application by brush or other equipment with no detrimental effects to finish.

Although the metals used in the examples were non-ferrous, test plates have shown that this process is as successful on cleaned ferrous metal piates and surfaces.

Claims (Filed on 4 June 1982) 1. A vitreous enamelling process in which an aqueous enamelling composition containing glass and/or metal particles is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base, wherein a watersoluble alkyl cellulose is included in the composition as a suspending agent for the particles.

2. A process according to claim 1 , wherein firing is carried out rapidly at 500-11 000C.

3. A process according to claim 1 or 2, wherein the alkyl cellulose is selected from methyl cellulose with a degree of substitution of 0.72.6, ethyl cellulose with a degree of substitution of 0.5-1.3 and isopropyl cellulose with a degree of substitution of 0.4-0.9.

4. A process according to claim 1, substantially as described in any of the Examples.

5. A substrate which has been enamelled by a process according to any preceding claim.

New claims or amendments to claims filed on 1 7-82 Superseded claim 1 New or amended claim: 1. A vitreous enamelling process in which an aqueous enamelling composition containing glass

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

SPECIFICATION Enamelling process This invention concerns vitreous enamelling processes in which an enamelling composition is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base.

When the substrate is glass, the composition and the glaze may contain particles (powder or flakes) of a metal such as gold or silver instead of or in addition to particles of glass. Because of the nature of the composition, and particularly the presence of glass, firing is carried out rapidly (perhaps for 2 or 3 minutes) at a temperature of 500-1 1000C.

According to the invention, a water-soluble alkyl cellulose is used as a suspending agent for glass and/or metal particles in an aqueous vitreous enamelling composition of the type just described. Water-soluble alkyl celluloses have a long shelf life, can be premixed with glass or metal particles, can be used with tap water, can be used at various concentrations to give the desired viscosity, can be fired wet, do not bloom the glass or leave a carbonaceous residue and can be used with flame heating as well as furnace heating.

The preferred alkyl celluloses are methyl cellulose with a degree of substitution of between 0.7-2.6 ethyl cellulose with a degree of substitution of between 0.5-1.3 Isopropyl cellulose with a degree of substitution of between 0.4-0.9.

Example 1 A vitreous enamelling composition was made up as follows:- Glass particles (100 mesh) 77.8% Methyl cellulose (Degree of substitution 1.6) 0.3% Water 21.9% This composition was used for laying on with a palate knife, or similar, onto a 14 carat gold base to provide a decorative effect and the whole was fired in a furnace at 800 deg. C. for approximately 2 minutes. A fine transparent glaze was obtained.

Example 2 This vitreous enamelling process was repeated except that the composition of the mixture was altered to that below, in order that glass enamel could be sprayed by compressed air spraygun onto a silver plate.

Composition Glass particles (400 mesh) 56.1% Methyl cellulose (Degree of substitution=1.6) 0.3% Water 43.6% This plate was allowed to dry in air at room temperature and fired in a furnace at 750 deg. C.

for approximately 2 minutes.

Again a fine transparent glaze was obtained.

Example 3 It was required to adhere thin gold and silver paillons and shims onto a glass on gold surface in order to sandwich the gold and silver pieces between the base glass and further clear glass overlay. This was achieved by making a composition of binder containing 0.1% methyl cellulose (degree of substitution=1.6) in water w/v. The gold and silver paillons and shims were laid onto the surface of the base glass which had been precoated with binder immediately before laying. After drying the whole was refired at 750 deg. C. for approximately 1 EF minutes, cooled and overlay glass (composition as in Example 1) was administered and fired as in Example 1.

A clear glaze was produced which had embedded in its interior the gold and silver metal pieces as they had been placed with no movement or blemish.

The ratio of composition of binder: water: glass may be altered to facilitate application by brush or other equipment with no detrimental effects to finish.

Although the metals used in the examples were non-ferrous, test plates have shown that this process is as successful on cleaned ferrous metal piates and surfaces.

Claims (Filed on 4 June 1982)

1. A vitreous enamelling process in which an aqueous enamelling composition containing glass and/or metal particles is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base, wherein a watersoluble alkyl cellulose is included in the composition as a suspending agent for the particles.

2. A process according to claim 1 , wherein firing is carried out rapidly at 500-11 000C.

3. A process according to claim 1 or 2, wherein the alkyl cellulose is selected from methyl cellulose with a degree of substitution of 0.72.6, ethyl cellulose with a degree of substitution of 0.5-1.3 and isopropyl cellulose with a degree of substitution of 0.4-0.9.

4. A process according to claim 1, substantially as described in any of the Examples.

5. A substrate which has been enamelled by a process according to any preceding claim.

New claims or amendments to claims filed on 1 7-82 Superseded claim 1 New or amended claim:

1. A vitreous enamelling process in which an aqueous enamelling composition containing glass and/or metal particles is coated onto a metal or glass substrate and fired to form a glaze with a substantially transparent base, wherein a watersoluble alkyl cellulose is included in the composition as a suspending and binding agent for the particles.