Process for preparing individualized, polycarboxylic acid crosslinked fibers
First Claim
1. A process for making individualized, twisted and curled, crosslinked wood pulp cellulosic fibers, said process comprising the steps of:
- a. providing wood pulp cellulosic fibers;
b. contacting said fibers with a solution containing a C2 -C9 polycarboxylic acid crosslinking agent, wherein said C2 -C9 polycarboxylic acid crosslinking agent is selected from the group consisting of;
(i) aliphatic and alicyclic C2 -C9 polycarboxylic acids having at least three carboxyl groups per molecule; and
(ii) aliphatic and alicyclic C2 -C9 polycarboxylic acids having two carboxyl groups per molecule and having a carbon-carbon double bond located alpha, beta to one or both of the carboxyl groups, wherein one carboxyl group in said C2 -C9 polycarboxylic acid crosslinking agent is separated from a second carboxyl group by either two or three carbon atoms;
c. mechanically separating said fibers into substantially individual form; and
d. drying said fibers and heating said fibers to cause said crosslinking agent to react with said fibers to form crosslink bonds while said fibers are in substantially individual form, to from intrafiber ester crosslink bonds;
said fibers being contacted with a sufficient amount of crosslinking agent such that from about 0.5 mole % to about 10.0 mole % of the crosslinking agent, calculated on a cellulose anhydroglucose molar basis, reacts with said fibers to form said intrafiber ester crosslink bonds, said crosslinked fibers having a water retention value of from about 28 to about 60.
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Abstract
Disclosed is a process for making individualized, crosslinked fibers which includes the steps of providing cellulosic fibers, contacting the fibers with a solution containing a C2 -C9 polycarboxylic acid crosslinking agent, mechanically separating the fibers into substantially individual form, drying the fibers and reacting the crosslinking agent with the individualized fibers to form intrafiber crosslink bonds. Preferably, the crosslinking agent is citric acid, and preferably, between about 0.5 mole % and about 10.0 mole % of the crosslinking agent reacts to form the intrafiber crosslink bonds. The individualized, crosslinked fibers are useful in a variety of absorbent structure applications.
232 Citations
27 Claims
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1. A process for making individualized, twisted and curled, crosslinked wood pulp cellulosic fibers, said process comprising the steps of:
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a. providing wood pulp cellulosic fibers; b. contacting said fibers with a solution containing a C2 -C9 polycarboxylic acid crosslinking agent, wherein said C2 -C9 polycarboxylic acid crosslinking agent is selected from the group consisting of; (i) aliphatic and alicyclic C2 -C9 polycarboxylic acids having at least three carboxyl groups per molecule; and (ii) aliphatic and alicyclic C2 -C9 polycarboxylic acids having two carboxyl groups per molecule and having a carbon-carbon double bond located alpha, beta to one or both of the carboxyl groups, wherein one carboxyl group in said C2 -C9 polycarboxylic acid crosslinking agent is separated from a second carboxyl group by either two or three carbon atoms; c. mechanically separating said fibers into substantially individual form; and d. drying said fibers and heating said fibers to cause said crosslinking agent to react with said fibers to form crosslink bonds while said fibers are in substantially individual form, to from intrafiber ester crosslink bonds;
said fibers being contacted with a sufficient amount of crosslinking agent such that from about 0.5 mole % to about 10.0 mole % of the crosslinking agent, calculated on a cellulose anhydroglucose molar basis, reacts with said fibers to form said intrafiber ester crosslink bonds, said crosslinked fibers having a water retention value of from about 28 to about 60. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A process for making individualized, crosslinked wood pulp cellulosic fibers, said process comprising the steps of:
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a. providing wood pulp cellulosic fibers; b. contacting said fibers with a solution containing a C2 -C9 polycarboxylic acid crosslinking agent, wherein said C2 -C9 polycarboxylic acid crosslinking agent is selected from the group consisting of; (i) aliphatic and alicyclic C2 -C9 polycarboxylic acids having at least three carboxyl groups per molecule; and (ii) aliphatic and alicyclic C2 -C9 polycarboxylic acids having two carboxyl groups per molecule and having a carbon-carbon double bond located alpha, beta to one or both of the carboxyl groups, wherein one carboxyl group in said C2 -C9 polycarboxylic acid crosslinking agent is separated from a second carboxyl group by either two or three carbon atoms; c. drying said fibers; d. mechanically separating said fibers into substantially individual form; and e. heating said fibers to cause said crosslinking agent to react with said fibers to form crosslink bonds while said fibers are in substantially individual form, to from intrafiber ester crosslink bonds;
said fibers being contacted with a sufficient amount of crosslinking agent such that from about 0.5 mole % to about 10.0 mole % of the crosslinking agent, calculated on a cellulose anhydroglucose molar basis, reacts with said fibers to form said intrafiber ester crosslink bonds, said crosslinked fibers having a water retention value of from about 28 to about 60.
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Specification