Sulfopolyesters for paper strength and process
AssigneeEastman Chemical Company
InventorsRakesh Kumar Gupta, Daniel William Klosiewicz, Melvin Glenn Mitchell, Marvin Lynn Mitchell
Life of this patent
Estimating the term…
Abstract
Sulfopolyester thermoplastic resins provide advantages in papermaking processes and in paper products including paperboard. Improvements in wet strength and dry strength of paper products are achieved by addition of sulfopolyester thermoplastic resins and cationic strength additives during the paper making process. The use of sulfopolyester thermoplastic resins in paper products also significantly enhances the repulpability of the paper.
Claims21
A repulpable paper product comprising:
- papermaking fibers;
- a cationic strength additive;
- and a thermoplastic sulfopolyester resin,
- wherein the papermaking fibers are selected from woody fibers, softwood fibers, hardwood fibers, non-woody fibers, synthetic polymeric fibers, recycled fibers, glass fibers, or combinations thereof,
- wherein the synthetic polymeric fibers are greater than 50% of the total papermaking fiber,
- wherein said synthetic polymeric fibers have a mean fiber diameter of less than 5 microns.
A method of improving the wet-strength of cellulosic paper comprising adding a cationic strength additive and a sulfopolyester thermoplastic resin to papermaking fibers during the papermaking process;
- wherein the papermaking fibers are selected from woody fibers, softwood fibers, hardwood fibers, non-woody fibers, synthetic polymeric fibers, recycled fibers, glass fibers, or combinations thereof,
- wherein the synthetic polymeric fibers are greater than 50% of the total papermaking fiber,
- wherein said synthetic polymeric fibers have a mean fiber diameter of less than 5 microns, and wherein the paper comprises said papermaking fibers, said cationic strength additive and said sulfopolyester thermoplastic resin.
A paper product comprising:
- papermaking fibers consisting of one or more of woody fibers, softwood fibers, hardwood fibers, non-woody fibers, synthetic polymeric fibers, recycled fibers, or glass fibers;
- cationic strength additives consisting of one or more of polyacrylamide resins, polyamide epihalohydrin resins, polyamine epihalohydrin resins, polyamidoamine epichalohydrin resins, polyalkyleneimine resins, urea-formaldehyde resins, melamine-formaldehyde resins, or cationic polysaccharides;
- and
- thermoplastic sulfopolyester resins comprising
- (i) residues of one or more dicarboxylic acids;
- (ii) about 4 to about 40 mole %, based on the total repeating units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;
- (iii) one or more diol residues wherein at least 25 mole %, based on the total diol residues, is a poly(ethylene glycol) having a structure H—(OCH2—CH2)n—OH wherein n is an integer in the range of 2 to about 500;
- and
- (iv) 0 to about 25 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof,
- wherein the synthetic polymeric fibers are greater than 50% of the total papermaking fiber,
- wherein said synthetic polymeric fibers have a mean fiber diameter of less than 5 microns.
Dependencies are inferred from the claim text.