Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
224 words
A method of chemically strengthening a glass article which comprises (1) applying a metal oxide-forming compound selected from the group consisting of tin compounds, titanium compounds, zirconium compounds and vanadium compounds to the outer surface of a heated glass article to form a metal oxide coating having a thickness of 50 to 130 Angstroms on the outer surface of the glass article, (2) applying a concentrated mixed solution of potassium chloride and potassium nitrate having a potassium chloride to potassium nitrate weight ratio of 85 to 45 : 15 to 55, or a concentrated mixed solution of potassium sulfate and potassium nitrate having a potassium sulfate to potassium nitrate weight ratio of 30 to 100 : 70 to 0, to the outer and inner surfaces of the thus treated glass article having a temperature of 30° to 75° C., (3) maintaining the resultant glass article at an elevated temperature below the strain point of the glass but as near the strain point as possible for a period of time sufficient to obtain a compressive stress layer having a depth of at least 10 microns and a compressive stress of at least 700 kg/cm 2 , (4) cooling the thus heated glass article to room temperature and removing the mixture of the potassium salts remaining on the outer and inner surfaces of the glass article.
Claim 2
Independent Claim
224 words
A method of chemically strengthening a glass article which comprises (1) applying a metal oxide-forming compound selected from the group consisting of tin compounds, titanium compounds, zirconium compounds and vanadium compounds to the outer surface of a heated glass article to form a metal oxide coating having a thickness of 50 to 130 Angstroms on the outer surface of the glass article, (2) applying a concentrated mixed solution of potassium chloride and potassium nitrate having a potassium chloride to potassium nitrate weight ratio of 85 to 45 : 15 to 55, or a concentrated mixed solution of potassium sulfate and potassium nitrate having a potassium sulfate to potassium nitrate weight ratio of 30 to 100 : 70 to 0, to the outer and inner surfaces of the thus treated glass article having a temperature of 30° to 75° C., (3) maintaining the resultant glass article at an elevated temperature below the strain point of the glass but as near the strain point as possible for a period of time sufficient to obtain a compressive stress layer having a depth of at least 10 microns and a compressive stress of at least 700 kg/cm 2 , (4) cooling the thus heated glass article to room temperature and removing the mixture of the potassium salts remaining on the outer and inner surfaces of the glass article.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein in the mixed solution of potassium chloride and potassium nitrate, a part of the potassium chloride and potassium nitrate is substituted by potassium sulfate.
Claim 4
Dependent Claim
18 words
The method of claim 1, wherein the thickness of the metal oxide coating is 70 to 100 Angstroms.
Claim 5
Dependent Claim
39 words
The method of claim 1, wherein in the mixed solution of potassium sulfate and potassium nitrate, the quantity of potassium nitrate being greater than zero, a part of the potassium sulfate and potassium nitrate is substituted by potassium chloride.
Claim 6
Dependent Claim
21 words
The method of claim 1, wherein wetting aid is added to the mixed solution in a quantity of 0.2 to 1%.
Claim 7
Dependent Claim
18 words
The method of claim 5, wherein the wetting aid is selected from the group consisting of anionic surfactants.
Claim 8
Dependent Claim
19 words
The method of claim 1, wherein the mixed solution is applied to the glass article by dipping or spraying.
Claim 9
Dependent Claim
17 words
The method of claim 1, wherein the temperature of the mixed solution is 50° to 75° C.
Claim 10
Dependent Claim
26 words
The method of claim 1, wherein the liquidus temperature of the mixed salt is higher than or substantially equal to the strain point of the glass.
Claim 11
Dependent Claim
20 words
The method of claim 1, wherein the temperature of the glass article in step (2) is 50° to 60° C.