Hydroxyalkylated cross-linked regenerated cellulose and method of preparation thereof

Claim 2

A water insoluble, hydrophilic, water swellable hydroxy C 2 -C 4 alkylated cross-linked regenerated cellulose prepared from the reaction of up to 20% (V/W based on cellulose) cross-linking agent comprising a bifunctional compound of formula XRY wherein X and Y which may be the same or different is each halo or epoxy and R is an aliphatic residue, up to 100% (V/W based on cellulose) hydroxy C 2 -C 4 alkylating agent and regenerated cellulose.

Claim 3

The product of claim 1 wherein said cross-linking agent is epichlorohydrin.

Claim 4

The product of claim 2 wherein said hydroxy C 2 -C 4 alkylating agent is selected from the group consisting of ethylene oxide and propylene oxide.

Claim 5

The product of claim 2 wherein said hydroxy C 2 -C 4 alkylating agent is propylene oxide.

Claim 6

The product of claim 4 wherein the particle size of the regenerated cellulose starting material is between 50-75μ.

Claim 7

The product of claim 1 prepared using 2-8% (V/W based on cellulose) epichlorohydrin and 50% (V/W based on cellulose) propylene oxide.

Claim 8

A process for preparing a water insoluble, hydrophilic water swellable hydroxy C 2 -C 4 alkylated cross-linked regenerated cellulose which comprises mixing regenerated cellulose in an aqueous alkaline medium with up to 20% (V/W based on cellulose) of a cross-linking agent comprising a bifunctional compound of formula XRY wherein X and Y which may be the same or different is each halo or epoxy and R is an aliphatic residue, up to 100% (V/W based on cellulose) of an hydroxy C 2 -C 4 alkylating agent with agitation or stirring until substantially all swelling is completed and substantially all liquid absorbed, sealing the swollen mixture in a closed vessel and heating the mixture to an elevated temperature in excess of the boiling temperature of said hydroxy C 2 -C 4 alkylating agent and maintaining the mixture in excess of said boiling temperature until said reaction is substantially complete, and recovering the product from said vessel.

Claim 9

A process for preparing a water insoluble, hydrophilic water swellable hydroxy C 2 -C 4 alkylated cross-linked regenerated cellulose which comprises mixing regenerated cellulose in an aqueous alkaline medium with up to 20% (V/W based on cellulose) of a cross-linking agent comprising a bifunctional compound of formula XRY wherein X and Y which may be the same or different is each halo or epoxy and R is an aliphatic residue, up to 100% (V/W based on cellulose) of an hydroxy C 2 -C 4 alkylating agent with agitation or stirring until substantially all swelling is completed and substantially all liquid absorbed, sealing the swollen mixture in a closed vessel and heating the mixture to an elevated temperature in excess of the boiling temperature of said hydroxy C 2 -C 4 alkylating agent and maintaining the mixture in excess of said boiling temperature until said reaction is substantially complete, and recovering the product from said vessel.

Claim 10

The process according to claim 7 wherein said aqueous alkaline solution is a dilute sodium hydroxide solution, said cross-linking agent is epichlorohydrin, said hydroxy C 2 -C 4 propylating agent is propylene oxide and said elevated temperature is about 60° C.

Claim 11

The process of claim 8 wherein from 2-8% epichlorohydrin and 40-50% propylene oxide are employed.

Claim 12

The process of claim 8 wherein the regenerated cellulose used has a particle size between 50-75μ.

Claim 13

A process for preparing a water insoluble, hydrophilic water swellable hydroxy C 2 -C 4 alkylated cross-linked regenerated cellulose which comprises mixing cross-linked regenerated cellulose in an aqueous alkaline medium with up to 100% (V/W based on cellulose) of an hydroxy C 2 -C 4 alkylating agent with agitation or stirring until substantially all swelling is completed and substantially all liquid absorbed, sealing the swollen mixture in a closed vessel and heating the mixture to an elevated temperature in excess of the boiling temperature of said hydroxy C 2 -C 4 alkylating agent and maintaining the mixture in excess of said boiling temperature until said reaction is substantially complete, and recovering the product from said vessel.

Claim 14

A process for preparing a water insoluble, hydrophilic water swellable hydroxy C 2 -C 4 alkylated cross-linked regenerated cellulose which comprises mixing cross-linked regenerated cellulose in an aqueous alkaline medium with up to 100% (V/W based on cellulose) of an hydroxy C 2 -C 4 alkylating agent with agitation or stirring until substantially all swelling is completed and substantially all liquid absorbed, sealing the swollen mixture in a closed vessel and heating the mixture to an elevated temperature in excess of the boiling temperature of said hydroxy C 2 -C 4 alkylating agent and maintaining the mixture in excess of said boiling temperature until said reaction is substantially complete, and recovering the product from said vessel.