Starch compositions and methods for use in papermaking
AssigneeCargill, Incorporated
InventorsKevin Ray Anderson, David Edward Garlie
Life of this patent
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Abstract
Starch compositions, including cationic crosslinked starches, and methods of using those starches in papermaking are disclosed. In particular, a cationized crosslinked starch and use of the starch in the wet end system of a paper machine is disclosed. The starch compositions of the disclosure are particularly adapted for customization for specific wet end systems, and allow for modification to correspond to variations in the wet end of the papermaking machine.
Claims61
A papermaking process comprising the steps of:
- a) providing a starch component comprising a cationized crosslinked starch having a hot paste viscosity in the measured range of from about 10 cps to about 3000 cps when measured in a Brookfield viscometer at about 95° C. using a No. 21 spindle at 20 rpm with a solids level of 2 percent;
- b) cooking a first portion of the starch component to generate a cooked starch component, said cooking comprising cooking the starch component at first average cooking temperature below 330° F. for a first period of time;
- c) dewatering a paper furnish, the paper furnish including:
- (i) cellulosic fibers in an aqueous slurry,
- (ii) microparticles comprising at least 50 percent by weight particles having an average particle size of no greater than 1 micron, and
- (iii) the cooked starch component;
- and
- d) adjusting the dewatering rate by cooking a second portion of the starch component at a second average cooking temperature at least 10° F. different than the first average cooking temperature and adding the second portion of the starch to the paper furnish.
A papermaking process comprising the steps of:
- a) proving providing a starch component comprising a cationized crosslinked starch having a hot paste viscosity in the range of from about 10 cps to about 3000 cps as measured in a Brookfield viscometer at about 95° C. using a No. 21 spindle at 20 rpm with a solids level of 2 percent;
- b) cooking a first portion of the starch component to generate a cooked starch component, said cooking comprising cooking the starch component at a first average cooking temperature below 330° F. for a first period of time;
- c) dewatering a paper furnish, the paper furnish including:
- (i) cellulosic fibers in an aqueous slurry,
- (ii) microparticles comprising at least 50 percent by weight particles having an average particle size of no greater than 1 micron, and
- (iii) the cooked starch component;
- and;
- d) adjusting first pass retention during dewatering by cooking a second portion of the starch composition at a second average cooking temperature at least 10° F. different than the first average cooking temperature and adding the second portion of the starch to the paper furnish.
A cooked cationic crosslinked starch paste having a viscosity of from about 95 to about 250 cps, as determined by using a Brookfield viscometer at a measurement temperature of about 150° F. using Spindle 21 at 20 rpm, at a solids level of about 1.2% to about 1.4%.
A cooked cationic crosslinked starch paste having a viscosity of from about 95 to about 250 cps as determined by using a Brookfield viscometer at a measurement temperature of about 150° F. using Spindle 21 at 20 rpm at a solids level of about 1.2% to about 1.4%, prepared by cooking a cationic crosslinked starch having a hot paste viscosity in the range of from about 10 cps to about 3000 cps as measured after 10 minutes on a Brookfield viscometer at about 95° C. using a No. 21 spindle at 20 rpm at a solids level of 2 percent.
A process for producing a cooked cationic crosslinked starch paste having a viscosity of from about 95 to about 250 cps, as determined by using a Brookfield viscometer at a measurement temperature of about 150° F. using Spindle 21 at 20 rpm, at a solids level of about 1.2% to about 1.4%, comprising cooking a cationic crosslinked starch having a hot paste viscosity in the range of from about 10 cps to about 3000 cps as measured after 10 minutes on a Brookfield viscometer at about 95° C. using a No. 21 spindle at 20 rpm at a solids level of 2 percent.
Dependencies are inferred from the claim text.