Method Of Preparation Of An Aqueous Composition Of Zirconium Carbonate And An Alkaline Metal Salt And Use Thereof
The invention relates to a process for the preparation of an aqueous composition of zirconium carbonate and an alkali metal salt in which a zirconium compound and an alkali metal bicarbonate are reacted, in the aqueous phase, with a bicarbonate to zirconium molar ratio equal to or greater than 4:1. The invention also relates to the use of the said aqueous composition of zirconium carbonate and an alkali metal salt as insolubilizing agent in a coating bath for paper or board.
1 . A process for the preparation of an aqueous composition of zirconium carbonate and an alkali metal salt comprising the step of reacting, in an aqueous phase, a zirconium compound and an alkali metal bicarbonate, wherein the bicarbonate to zirconium molar ratio is equal to or greater than 4:1.
2 . A process according to claim 1 , wherein the zirconium compound is selected from the group consisting of basic zirconium carbonate, zirconium oxychloride (ZrOCl 2 ) and basic zirconium sulphate.
3 . A process according to claim 1 , wherein the alkali metal bicarbonate is selected from the group consisting of potassium bicarbonate and sodium bicarbonate.
4 . A process according to claim 1 , wherein the bicarbonate to zirconium molar ratio is between approximately 4:1 and approximately 6:1.
5 . A process according to claim 1 , wherein the bicarbonate to zirconium molar ratio is approximately 4:1.
6 . A process according to claim 1 , further comprising the step of adding an a stabilizing agent.
7 . A process for the treatment of a cellulose-based product comprising the step of insolubilizing a natural or synthetic binder with an aqueous composition of zirconium carbonate and an alkali metal salt produced by the process according to claim 1 .
8 . A process according to claim 7 , wherein the cellulose-based product is selected from the group consisting of paper and board.
9 . A process according to either of claim 7 , wherein the insolubilizing step is carried out in a coating bath.
10 . A process according to claim 9 , wherein the coating bath is intended for the impregnating or coating of paper or board.
11 . A process according to claim 7 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a concentration of approximately 10 to 12% by weight of zirconium, expressed as ZrO 2 , and/or a solids content of 50 to 55%.
12 . A process according to claim 7 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a pH of greater than 8 and less than 10.
13 . A process for the treatment of a cellulose-based product, in which a coating bath comprising at least one binder, an insolubilizing agent and optionally a pigment is applied at the surface of the cellulose-based product, wherein the insolubilizing agent is an aqueous composition of zirconium carbonate and an alkali metal salt produced according to the process of claim 1 .
14 . A process for the treatment of a cellulose-based product in which a coating bath comprising at least one binder, an insolubilizing agent and optionally a pigment is brought into contact with the cellulose-based product, wherein the insolubilizing agent is an aqueous composition of zirconium carbonate and an alkali metal salt produced according to the process of claim 1 .
15 . A process according to claim 13 , wherein the cellulose-based product is selected from the group consisting of paper and board.
16 . A process according to claim 13 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a concentration from approximately 10 to 12% by weight of zirconium, expressed as ZrO 2 , and/or a solids content of 50 to 55%.
17 . A process according to claim 13 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a pH of greater than 8 and less than 10.
18 . A process according to claim 7 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a pH of between approximately 8.5 and 9.6.
19 . A process according to claim 13 , wherein the aqueous composition of zirconium carbonate and an alkali metal salt has a pH of between approximately 8.5 and 9.6.