Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
194 words
A process for producing a highly water absorptive amorphous resin, which comprises (a) suspending an aqueous solution of partially neutralized alkali metal acrylate wherein about 50 to 100% by mole of the carboxyl group has been neutralized to its alkali metal salt and at least one water soluble radical polymerization initiator, in a hydrocarbon solvent containing a surfactant having a HLB value of 8˜12; (b) subjecting the mixture to inverse suspension polymerization while raising the internal temperature of the reactor successively to 70° C., to 60°˜67° C., and then to 75° C., to undergo phase-transition; (c) during or after the polymerization, separating the moisture from the produced polymer by azeotropic distillation to reduce the water content to about 15 to 55% by weight, and filtering to remove the solvent; (d) adding a crosslinking agent having three or more reactive epoxy groups which is dissolved in methanol, wherein the amount of the crosslinking agent is 0.005˜15% by weight based on the produced polymer, and incubating for 1˜2 hours at temperatures 70° to 85° C.; and (e) washing with methanol, filtering, and drying at temperatures of 90° to 175° C. to obtain the water absorptive resin.
Claim 2
Dependent Claim
194 words
A process for producing a highly water absorptive amorphous resin, which comprises (a) suspending an aqueous solution of partially neutralized alkali metal acrylate wherein about 50 to 100% by mole of the carboxyl group has been neutralized to its alkali metal salt and at least one water soluble radical polymerization initiator, in a hydrocarbon solvent containing a surfactant having a HLB value of 8˜12; (b) subjecting the mixture to inverse suspension polymerization while raising the internal temperature of the reactor successively to 70° C., to 60°˜67° C., and then to 75° C., to undergo phase-transition; (c) during or after the polymerization, separating the moisture from the produced polymer by azeotropic distillation to reduce the water content to about 15 to 55% by weight, and filtering to remove the solvent; (d) adding a crosslinking agent having three or more reactive epoxy groups which is dissolved in methanol, wherein the amount of the crosslinking agent is 0.005˜15% by weight based on the produced polymer, and incubating for 1˜2 hours at temperatures 70° to 85° C.; and (e) washing with methanol, filtering, and drying at temperatures of 90° to 175° C. to obtain the water absorptive resin.
Claim 3
Dependent Claim
17 words
The process according to claim 1, wherein the surfactant is sorbitan monolaurate or Ryoto Sugar Ester S-970®.
Claim 4
Dependent Claim
21 words
The process according to claim 1, wherein the hydrocarbon solvent is selected from the group consisting of n-hexane, n-heptane and cyclohexane.
Claim 5
Dependent Claim
12 words
The process according to claim 1, wherein the hydrocarbon solvent is cyclohexane.
Claim 6
Dependent Claim
27 words
The process according to claim 1, wherein the water soluble radical polymerization initiator is selected from the group consisting of ammonium persulfate, potassium persulfate and hydrogen peroxide.
Claim 7
Dependent Claim
16 words
The process according to claim 1, wherein the water soluble radical polymerization initiator is potassium persulfate.
Claim 8
Dependent Claim
28 words
The process according to claim 1, wherein the crosslinking agent is selected from the group consisting of glycerol polyglycidyl ether, trimethylol propane polyglycidyl ether and sorbitol polyglycidyl ether.
Claim 9
Dependent Claim
31 words
The process according to claim 1, wherein the partially neutralized alkali metal acrylate is prepared by addition of an alkali metal hydroxide such as sodium hydroxide, lithium hydroxide or potassium hydroxide.