Production of paper using slica-based-sols
View Patent ↗A process for the production of paper which includes the steps of providing an aqueous suspension containing cellulosic fibers, and optional fillers; adding to the suspension: (a) at least one charged organic polymer; and (b) an aqueous sol containing silica-based particles; wherein the sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; and (iii) a molar ratio of SiO 2 to M 2 O, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and (III) forming and draining the suspension on a wire. The invention is further directed to processes for making paper wherein the added sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; and (iii) a silica content of at least 10% by weight, or wherein the added sol has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 7 to 25 cP; (iii) a silica content of at least 10% by weight; (iv) a molar ratio of SiO 2 to M 2 O, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and (v) a pH of at least 10.6. The invention is further directed to a process for making paper wherein the added sol is modified by an aluminum-containing compound, a boron-containing compound or a mixture thereof and has: (i) an S-value within the range of from 10 to 45%; (ii) a viscosity within the range of from 5 to 40 cP; (iii) a silica content of at least 10% by weight; and (iv) a molar ratio of SiO 2 to M 2 O, where M being alkali metal or ammonium, within the range of from 10:1 to 40:1.
1. A process for the production of paper which comprises:
(I) providing an aqueous suspension containing cellulosic fibers, and optional fillers;
(II) adding to the suspension:
(a) at least one charged organic polymer; and
(b) an aqueous sol containing silica-based particles;
wherein the sol has:
(i) an S-value within the range of from 10 to 45%;
(ii) a viscosity within the range of from 5 to 40 cP; and
(iii) a molar ratio of SiO 2 to M 2 O, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and
(III) forming and draining the suspension on a wire.
2. The process according to claim 1 , wherein the silica-based particles have a specific surface area within the range of from 300 to 1050 m 2 /g.
3. The process according to claim 1 , wherein the silica-based particles have a specific surface area within the range of from 550 to 725 m 2 /g.
4. The process according to claim 1 , wherein the silica-based particles have a specific surface area within the range of from 775 to 1050 m 2 /g.
5. The process according to claim 1 , wherein the charged organic polymer is cationic starch or cationic polyacrylamide.
6. The process according to claim 1 , wherein before adding the aqueous sol containing silica-based particles to the suspension the aqueous sol is diluted or mixed with water to form an aqueous sol having a silica content of from 0.05 to 5% by weight.
7. The process according to of claim 1 , wherein the aqueous sol containing silica-based particles is added to the suspension in an amount of from 0.005 to 0.5% by weight, calculated as SiO 2 and based on dry cellulosic fibers and optional fillers.
8. A process for the production of paper which comprises
(I) providing an aqueous suspension containing cellulosic fibers, and optional fillers;
(II) adding to the suspension:
(a) at least one charged organic polymer; and
(b) an aqueous sol containing silica-based particles;
wherein the sol has:
(i) an S-value within the range of from 10 to 45%;
(ii) a viscosity within the range of from 5 to 40 cP; and
(iii) a silica content of at least 10% by weight; and
(III) forming and draining the suspension on a wire.
9. The process according to claim 8 , wherein the silica-based particles have a specific surface area within the range of from 300 to 1050 m 2 /g.
10. The process according to claim 8 , wherein the silica-based particles have a specific surface area within the range of from 550 to 725 m 2 /g.
11. The process according to claim 8 , wherein the silica-based particles have a specific surface area within the range of from 775 to 1050 m 2 /g.
12. The process according to claim 8 , wherein the charged organic polymer is cationic starch or cationic polyacrylamide.
13. The process according to claim 8 , wherein before adding the aqueous sol containing silica-based particles to the suspension the aqueous sol is diluted or mixed with water to form an aqueous sol having a silica content of from 0.05 to 5% by weight.
14. The process according to claim 8 , wherein the aqueous sol containing silica-based particles is added to the suspension in an amount of from 0.005 to 0.5% by weight, calculated as SiO 2 and based on dry cellulosic fibers and optional fillers.
15. A process for the production of paper which comprises:
(I) providing an aqueous suspension containing cellulosic fibers, and optional fillers;
(II) adding to the suspension:
(a) at least one charged organic polymer; and
(b) an aqueous sol containing silica-based particles;
wherein the sol has:
(i) an S-value within the range of from 10 to 45%;
(ii) a viscosity within the range of from 7 to 25 cP;
(iii) a silica content of at least 10% by weight;
(iv) a molar ratio of SiO 2 to M 2 O, where M is alkali metal or ammonium, within the range of from 10:1 to 40:1; and
(v) a pH of at least 10.6; and
(III) forming and draining the suspension on a wire.
16. The process according to claim 15 , wherein the charged organic polymer is cationic starch or cationic polyacrylamide.
17. The process according to claim 15 , wherein before adding the aqueous sol containing silica-based particles to the suspension the aqueous sol is diluted or mixed with water to form an aqueous sol having a silica content of from 0.05 to 5% by weight.
18. The process according to of claim 15 , wherein the aqueous sol containing silica-based particles is added to the suspension in an amount of from 0.005 to 0.5% by weight, calculated as SiO 2 and based on dry cellulosic fibers and optional fillers.
19. A process for the production of paper which comprises:
(I) providing an aqueous suspension containing cellulosic fibers, and optional fillers;
(II) adding to the suspension:
(a) at least one charged organic polymer; and
(b) an aqueous sol containing silica-based particles;
wherein the sol is modified by an aluminium-containing compound, boron-containing compound or a mixture thereof and has:
(i) an S-value within the range of from 10 to 45%;
(ii) a viscosity within the range of from 5 to 40 cP;
(iii) a silica content of at least 10% by weight; and
(iv) a molar ratio of SiO 2 to M 2 O, where M being alkali metal or ammonium, within the range of from 10:1 to 40:1; and
(III) forming and draining the suspension on a wire.
20. The process according to claim 19 , wherein the charged organic polymer is cationic starch or cationic polyacrylamide.
21. The process according to claim 19 , wherein before adding the aqueous sol containing silica-based particles to the suspension the aqueous sol is diluted or mixed with water to form an aqueous sol having a silica content of from 0.05 to 5% by weight.
22. The process according to of claim 19 , wherein the aqueous sol containing silica-based particles is added to the suspension in an amount of from 0.005 to 0.5% by weight, calculated as SiO 2 and based on dry cellulosic fibers and optional fillers.