Polycarboxylated polymer, method of making, method of use, and superabsorbent compositions including the same
An aqueous superabsorbent polymer precursor composition that includes a superabsorbent polymer precursor prepared by polymerizing alpha,beta-ethylenically unsaturated carboxylic acid monomers in the presence of inorganic metal salt catalyst, and an optional metal ion containing crosslinking agent, and a method of making an absorbent article that includes contacting a mesh with a slurry that includes cellulose fibers to form a wet fiber mat, removing water from the wet fiber mat, contacting the wet cellulose fiber mat with the aqueous superabsorbent polymer precursor composition, and drying the mat.
1 . A method of making an absorbent article, said method comprising
contacting a mesh with a slurry comprising cellulose fibers to form a wet fiber mat;
removing water from said wet fiber mat;
contacting said wet cellulose fiber mat with an aqueous superabsorbent polymer precursor composition comprising
a superabsorbent polymer precursor prepared by polymerizing alpha,beta-ethylenically unsaturated carboxylic acid monomers in the presence of inorganic metal salt catalyst, and
a metal ion containing crosslinking agent; and
drying said mat.
2 . The method of claim 1 , wherein said absorbent article comprises no greater than 0.5 milligrams per square inch chloroform-soluble extractives.
3 . The method of claim 1 , wherein the resulting absorbent article comprises less than 300 ppm extractable alpha,beta-ethylenically unsaturated carboxylic acid monomer.
4 . The method of claim 1 , wherein said alpha,beta-ethylenically unsaturated carboxylic acid monomers comprise acrylic acid monomers.
5 . The method of claim 4 , wherein the resulting absorbent article comprises less than 200 ppm extractable acrylic acid monomer.
6 . The method of claim 4 , wherein the resulting absorbent article comprises less than 50 ppm acrylic acid monomer.
7 . The method of claim 1 , wherein said inorganic metal salt catalyst comprises ferrous sulfate.
8 . The method of claim 1 , wherein said inorganic metal salt catalyst is selected from the group consisting of ferrous nitrate, ferrous chloride, ferrous ammonium sulfate and combinations thereof.
9 . The method of claim 1 , wherein said inorganic metal salt catalyst is selected from the group consisting of manganese salts, magnesium salts, zinc salts, vanadium salts, calcium salts, and combinations thereof.
10 . The method of claim 1 , wherein said metal ion containing crosslinking agent comprises ammonium zirconyl carbonate.
11 . An aqueous superabsorbent polymer precursor composition comprising:
at least partially neutralized polycarboxylated polymer prepared from alpha,beta-ethylenically unsaturated carboxylic acid monomers;
inorganic metal salt catalyst; and
from 0.1% by weight to about 10% by weight metal ion containing crosslinking agent.
12 . The composition of claim 11 , wherein said alpha,beta-ethylenically unsaturated carboxylic acid monomers comprise acrylic acid monomers and wherein said composition, when dry, comprises less than 300 ppm acrylic acid monomer.
13 . The composition of claim 12 , wherein said composition, when dry, comprises less than 50 ppm acrylic acid monomer.
14 . The composition of claim 11 , wherein said inorganic metal salt catalyst comprises ferrous sulfate.
15 . The composition of claim 11 , which, when dry, comprises no greater than 0.5 mg/in 2 chloroform-soluble extractives.
16 . The composition of claim 11 , which, when dry, comprises no greater than 0.1 mg/in 2 chloroform-soluble extractives.
17 . A superabsorbent polymer prepared by drying the superabsorbent polymer precursor composition of claim 11 .
18 . A solution polymer comprising polyacrylic acid polymerized in the presence of ferrous sulfate catalyst, having a pH from 5.7 to 6.3, and a solids content of no greater than 50% by weight.
19 . A method of making a superabsorbent polymer precursor composition, said method comprising:
polymerizing alpha,beta-ethylenically unsaturated monomers in the presence of inorganic metal salt catalyst to form an aqueous solution polymer composition; and
adjusting the pH of said composition to a pH of from 5.7 to 6.3.
20 . The method of claim 19 further comprising
diluting said composition with water to a solids content of no greater than 10% by weight; and
adding a metal ion containing crosslinking agent.
21 . The method of claim 20 , wherein said metal ion containing crosslinking agent comprises ammonium zirconyl carbonate.
22 . The method of claim 20 , comprising adding no greater than 4% by weight said crosslinking agent.
23 . The method of claim 20 , wherein said composition, when cured, comprises less than 300 parts per million alpha,beta-ethylenically unsaturated carboxylic acid monomer.
24 . An absorbent article comprising:
a substrate comprising fibers; and
a superabsorbent polymer formed from an aqueous superabsorbent polymer precursor composition comprising
at least partially neutralized polycarboxylated polymer,
inorganic metal salt catalyst, and
a metal ion containing crosslinking agent.
25 . The absorbent article of claim 24 , wherein said polycarboxylated polymer is prepared from acrylic acid monomer, and said absorbent article comprises no greater than 0.5 g/in 2 chloroform-soluble extractives and no greater than 300 ppm acrylic acid monomer.
26 . Paper toweling comprising the absorbent article of claim 24 , wherein said substrate comprises cellulose fibers.
27 . The paper toweling of claim 26 , further comprising a second substrate comprising cellulose fibers, said superabsorbent polymer being disposed between said first substrate and said second substrate.
28 . The paper toweling of claim 26 , wherein said superabsorbent polymer is in the form of a discontinuous pattern on the cellulose fiber substrate.
29 . Cellulose tissue comprising a cellulose fiber web and a superabsorbent polymer derived from the composition of claim 11 .
30 . The absorbent article of claim 24 , wherein said article exhibits a water absorbency that is at least 10% greater than the water absorbency of the article without the superabsorbent polymer composition.
31 . The absorbent article of claim 24 , comprising from 1% by weight to 10% by weight said superabsorbent polymer.
32 . The absorbent article of claim 24 , comprising from 1% by weight to about 8% by weight superabsorbent polymer.
33 . The absorbent article of claim 24 , wherein said substrate comprises a nonwoven web.
34 . A method of making the absorbent article of claim 24 comprising:
a) contacting a substrate with a first composition comprising one of
i) an aqueous superabsorbent polymer composition comprising
at least partially neutralized polycarboxylated polymer, and
inorganic metal salt catalyst, and
ii) a metal ion containing crosslinking agent; and
b) contacting said substrate with a second composition comprising the other of
i) said aqueous superabsorbent polymer composition, and
ii) said metal ion containing crosslinking agent.
35 . A food package comprising:
a food substance; and
the absorbent article of claim 24 .
36 . The food package of claim 31 , wherein said food substance comprises at least one of meat, fish, fruit, and vegetables.
37 . A method of making an absorbent article comprising:
contacting a substrate comprising fibers with an aqueous solution comprising a polymer derived from alpha,beta-ethylenically unsaturated monomers and inorganic metal salt catalyst, said solution having a pH of from about 7 to about 10; and
drying said substrate.
38 . The method of claim 37 , wherein said solution further comprises a metal ion containing crosslinking agent.