US3887348A — Glass coloring process

Claim 1

Independent Claim 188 words

A PROCESS FOR IMPARTING A YELLOW COLORATION TO SODA-LIMESILICA GLASS BODIES OF ORDINARY COMPOSITION CONTAINING A SMALL CONCENTRATION OF REDUCING IONS IN AT LEAST THE SURFACE LAYERS OF A PORTION THEREOF AND HAVING NO VISIBLE COLORATION, COMPRISING THE STEPS OF: PLACING THE SURFACE OF SUCH A BODY WHICH IS ASSOCIATED WITH SUCH SURFACE LAYERS IN CONTACT WITH A CONTACTING MEDIUM COMPOSED OF A MIXTURE OF MOLTEN METAL SALTS, WHICH MIXTURE INCLUDES A SILVER SALT PRESENT IN A CONCENTRATION OF BETWEEN 0.01 PERCENT, BY WEIGHT, AND FURNISHING REDUCIBLE SILVER IONS CAPABLE OF BEING REDUCED BY THE REDUCING IONS IN THE SURFACE LAYERS IN SUCH A MANNER AS TO IMPART A YELLOW COLORATION TO THE BODY; SAID PLACING BEING UNDER CONCENTRATION, TEMPERATURE AND TIME CONDITIONS SUCH AS TO CAUSE SUCH REDUCIBLE IONS TO DIFFUSE INTO SUCH BODY SURFACE LAYERS WITHOUT GIVING A SIGNIFICANT VISIBLE COLORATION TO THE GLASS; AND SUBSEQUENT TO SUCH DIFFUSION, HEATING SUCH BODY TO A TEMPERATURE ABOVE THE STRAIN POINT OF THE GLASS AND HIGHER THAN THE TEMPERATURE EMPLOYED DURING SAID STEP OF PLACING FOR A TIME SUFFICIENT TO CAUSE THE BODY TO DEVELOP A YELLOW COLORATION.

Claim 2

Dependent Claim 188 words

A PROCESS FOR IMPARTING A YELLOW COLORATION TO SODA-LIMESILICA GLASS BODIES OF ORDINARY COMPOSITION CONTAINING A SMALL CONCENTRATION OF REDUCING IONS IN AT LEAST THE SURFACE LAYERS OF A PORTION THEREOF AND HAVING NO VISIBLE COLORATION, COMPRISING THE STEPS OF: PLACING THE SURFACE OF SUCH A BODY WHICH IS ASSOCIATED WITH SUCH SURFACE LAYERS IN CONTACT WITH A CONTACTING MEDIUM COMPOSED OF A MIXTURE OF MOLTEN METAL SALTS, WHICH MIXTURE INCLUDES A SILVER SALT PRESENT IN A CONCENTRATION OF BETWEEN 0.01 PERCENT, BY WEIGHT, AND FURNISHING REDUCIBLE SILVER IONS CAPABLE OF BEING REDUCED BY THE REDUCING IONS IN THE SURFACE LAYERS IN SUCH A MANNER AS TO IMPART A YELLOW COLORATION TO THE BODY; SAID PLACING BEING UNDER CONCENTRATION, TEMPERATURE AND TIME CONDITIONS SUCH AS TO CAUSE SUCH REDUCIBLE IONS TO DIFFUSE INTO SUCH BODY SURFACE LAYERS WITHOUT GIVING A SIGNIFICANT VISIBLE COLORATION TO THE GLASS; AND SUBSEQUENT TO SUCH DIFFUSION, HEATING SUCH BODY TO A TEMPERATURE ABOVE THE STRAIN POINT OF THE GLASS AND HIGHER THAN THE TEMPERATURE EMPLOYED DURING SAID STEP OF PLACING FOR A TIME SUFFICIENT TO CAUSE THE BODY TO DEVELOP A YELLOW COLORATION.

Claim 3

Dependent Claim 191 words

A process for imparting a yellow coloration to soda-lime-silica glass bodies of ordinary composition containing a small concentration of reducing ions in at least the surface layers of a portion thereof and having no visible coloration, comprising the steps of: placing the surface of such a body which is associated with such surface layers in contact with a contacting medium composed of a mixture of molten metal salts, which mixture includes a silver salt present in a concentration of between 0.01 percent and 3 percent, by weight, and furnishing reducible silver ions capable of being reduced by the reducing ions in the surface layers in such a manner as to impart a yellow coloration to the body; said placing being under concentration, temperature and time conditions such as to cause such reducible ions to diffuse into such body surface layers without giving a significant visible coloration to the glass; and subsequent to such diffusion, heating such body to a temperature above the strain point of the glass and higher than the temperature employed during said step of placing for a time sufficient to cause the body to develop a yellow coloration.

Claim 4

Dependent Claim 191 words

A process for imparting a yellow coloration to soda-lime-silica glass bodies of ordinary composition containing a small concentration of reducing ions in at least the surface layers of a portion thereof and having no visible coloration, comprising the steps of: placing the surface of such a body which is associated with such surface layers in contact with a contacting medium composed of a mixture of molten metal salts, which mixture includes a silver salt present in a concentration of between 0.01 percent and 3 percent, by weight, and furnishing reducible silver ions capable of being reduced by the reducing ions in the surface layers in such a manner as to impart a yellow coloration to the body; said placing being under concentration, temperature and time conditions such as to cause such reducible ions to diffuse into such body surface layers without giving a significant visible coloration to the glass; and subsequent to such diffusion, heating such body to a temperature above the strain point of the glass and higher than the temperature employed during said step of placing for a time sufficient to cause the body to develop a yellow coloration.

Claim 5

Dependent Claim 22 words

A process as defined in claim 1 wherein the medium contains less than 0.05 percent, by weight, of silver ion furnishing salt.

Claim 6

Dependent Claim 22 words

A process as defined in claim 1 wherein the medium contains less than 0.5 percent, by weight, of silver ion furnishing salt.

Claim 7

Dependent Claim 15 words

A process as defined in claim 1 wherein the medium additionally contains a zinc salt.

Claim 8

Dependent Claim 20 words

A process as defined in claim 1 wherein the salt furnishing reducible metal ions is a nitrate, chloride, or sulphate.

Claim 9

Dependent Claim 29 words

A process as defined in claim 1 wherein said step of maintaining is carried out in such a manner as to maintain the temperature at a value below 350*C.

Claim 10

Dependent Claim 39 words

A process as defined in claim 1 wherein the body is formed of drawn soda lime flat glass and said step of heating is carried out so as to heat the glass to a temperature of at least 500*C.

Claim 11

Dependent Claim 26 words

A method as defined in claim 1 further comprising, after said step of heating, rapidly cooling the body to induce compressive stresses in its surface layers.

Claim 12

Dependent Claim 67 words

A process as defined in claim 1 further comprising, during said heating step and while the body is at a temperature above the strain point of the glass, diffusing into the surface layers of the body further ions which reduce the coefficient of thermal expansion of the body, in exchange for other ions, and subsequently cooling the body to induce compressive stresses in the surface layers thereof.

Claim 13

Dependent Claim 31 words

A process as defined in claim 1 further comprising, during said heating step and while the temperature of the body is above the strain point of the glass, bending the body.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-06-02	1978-12-02	1979-06-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-06-02	1982-12-02	1983-06-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-06-02	1986-12-02	1987-06-03	$7700.00	Window Closed / Lapsed

Glass coloring process

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