Phospholipid lubricant for coating moving webs
View Patent ↗Lubricant formulations comprising a phospholipids such as lecithins and a low hydrophobic lipophilic balance (HLB) surfactant provide improved rheological properties for coating a rapidly moving web, such as a paper web. The low hydrophobic lipophilic balance (HLB) surfactant is preferably an alcohol ethoxylate having an HLB value of between 7 and 10 or more preferably between 7.5 and 9.5. The lubricant formulations of the invention are preferably applied to the paper web as part of a coating mixture. The lubricant is well-suited for short-dwell coating methods.
1. A lubricant additive mixture adapted for combination with an aqueous-based paper or paper board coating mixture, said additive mixture comprising, by weight, about 65-75% lecithin, about 5-20% of a fatty acid, about 5-20% of a fatty acid ester, and about 2-15% of a surfactant having an HLB value of less than about 10.
2. The lubricant additive mixture of claim 1 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
3. The lubricant additive mixture of claim 1 , wherein the additive mixture comprises 67-73% lecithin by weight.
4. The lubricant additive mixture of claim 1 , wherein the additive mixture comprises 68-72% lecithin by weight.
5. The lubricant additive mixture of claim 1 , wherein the surfactant is an alcohol ethoxylate.
6. The lubricant additive mixture of claim 1 , wherein the surfactant comprises at least one alcohol ethoxylate having an HLB value of between about 7 and about 10.
7. The lubricant additive mixture of claim 6 , wherein the surfactant is an alcohol ethoxylate having a primary or secondary alcohol residue having between 8 and 20 carbon atoms and an ethoxylate chain having between two and five ethylene glycol residues.
8. The lubricant additive mixture of claim 1 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
9. The lubricant additive mixture of claim 1 , wherein the surfactant is an alcohol ethoxylate of the formula:
wherein R is at least one C 8 -C 20 alkyl group which may be straight or branched and n represents an average value of the number of ethoxylate residues which is selected from real numbers of between about 2 and about 5.
10. The lubricant additive mixture of claim 9 , wherein R represents between 1-5 linear or branched C 8 -C 20 alkyl groups having the same or different number of carbon atoms and the same or different branching position.
11. The lubricant additive mixture of claim 10 , wherein n is a real number of between about 2.5 and about 4.
12. The lubricant additive mixture of claim 10 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
13. The lubricant additive mixture of claim 9 , wherein R represents between 1-4 linear C 8 -C 20 alkyl groups.
14. The lubricant additive mixture of claim 13 , wherein n is a real number of between about 2.5 and about 4.
15. The lubricant additive mixture of claim 13 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
16. The lubricant additive mixture of claim 13 , wherein R represents between 1-4 linear alkyl groups selected from nonyl, decyl undecyl, dodecyl, tetradecyl, hexadecyl, and octadecyl.
17. The lubricant additive mixture of claim 16 , wherein n is a real number of between about 2.5 and about 4.
18. The lubricant additive mixture of claim 16 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
19. The lubricant additive mixture of claim 13 , wherein R represents nonyl, decyl, undecyl, dodecyl, a mixture of nonyl and undecyl groups, a mixture of dodecyl and tetradecyl groups, a mixture of dodecyl, tetradecyl and hexadecyl groups, or a mixture of C 12-15 alkyl groups.
20. The lubricant additive mixture of claim 19 , wherein n is a real number of between about 2.5 and about 4.
21. The lubricant additive mixture of claim 19 , wherein the surfactant has an HLB value of between about 7.5 and about 9.5.
22. An aqueous-based paper or paper board coating mixture comprising clay and a lubricant additive mixture comprising, by weight, about 65-75% lecithin, about 5-20% of a fatty acid, about 5-20% of a fatty acid ester, and about 2-15% of a surfactant having an HLB value of less than about 10.
23. The coating mixture of claim 22 comprising a solid content by weight of between 50 and 75%.
24. The coating mixture of claim 22 , having the following composition by weight: 10-90% binder, 10-90% pigment and 0.2-5% of the lubricant additive mixture.
25. The coating mixture of claim 24 wherein the lubricant additive mixture comprises a fatty acid selected from the group consisting of linoleic acid, oleic acid, palmitic acid, acid stearic, and coconut fatty acid.
26. The lubricant additive mixture of claim 1 , wherein at least the lecithin and the surfactant are in the same phase.
27. The lubricant additive mixture of claim 1 , wherein the lecithin, the fatty acid, the fatty acid ester and the surfactant are in the same phase.