Adhesive polyethylene oxide hydrogel sheet and its production

• US 4,684,558 A
• Filed: 06/30/1986
• Issued: 08/04/1987
• Est. Priority Date: 06/30/1986
• Status: Expired due to Fees

• Current Assignee: Nepera, Inc.
• Original Assignee: Nepera, Inc.
• Inventors: Essmyer, John L., Keusch, Preston
• Primary Examiner(s): McCamish, Marion C.
• Application Number:
  US06/879,876
• Time in Patent Office: 400 Days
• Field of Search: 428/40, 428/220, 428/290, 204/168, 204/169
• US Class Current: 428/40.6
• CPC Class Codes: C08J 2371/02 Polyalkylene oxides
• CPC Class Codes: C08J 3/28 Treatment by wave energy or particle radiation
• CPC Class Codes: C09J 7/10 without carriers
• CPC Class Codes: Y10T 428/1424 Halogen containing compound

Abstract

A solid sheet of adhesive hydrophilic gel which is a homogeneous aqueous mixture, substantially free of unbound water, monomers and crosslinking agents, consisting essentially of an amount dispersed uniformly in water of from about 4 to 35 wt % of a crosslinked polyethylene oxide, effective to form with the water a tacky surfaced viscoelastic solid which sheet of hydrophilic gel is produced by subjecting a liquid film of an aqueous solution having a viscosity of about 2-2,000×10³ cps of a linear water soluble polyethylene oxide having a weight average molecular weight from about 0.02-6×10⁶ Daltons to an amount of high energy radiation effective to convert the liquid film to a sheet of the viscoelastic solid having an adhesive face.

Claims

1. A method for producing an adhesive sheet of hydrophilic gel which comprises the step of subjecting a liquid film of an aqueous solution having a viscosity of about 2-2,000×

10³ cps of a linear water soluble polyethylene oxide having a weight average molecular weight from about 0.02-6×

10⁶ Daltons, to an amount of high energy radiation from about 0.2 to 5.0 Mrads effective to convert the liquid film to a sheet of the viscoelastic solid having an adhesive face which in the rolling ball tack test gives a rolling ball distance of less than about 10 mm and gives an adhesion energy force in the Adhesion Energy Density Determination Test of about 2 to 80 g-cm/cm², which adhesive sheet has greater cohesive strength than adhesive strength, whereby the sheet can be removed from a surface to which it is affixed without leaving a visible residue.

2. A solid sheet from about 10 to 150 mils thick of an adhesive hydrophilic gel which is a homogenous aqueous mixture, substantially free of unbound water, monomers and crosslinking agents, consisting essentially of an amount dispersed uniformly in water of from about 4 to 35 wt % of a crosslinked polyethylene oxide, effective to form with the water a tacky surfaced viscoelastic solid, which sheet of hydrophilic gel is produced according to the process of claim 1.

3. A sheet of hydrophilic gel according to claim 2, wherein the hydrophilic gel contains immersed therein a low area-weight scrim.

4. A sheet of hydrophilic gel according to claim 3, wherein the scrim is a sheet of non-woven polyethylene.

5. A sheet of hydrophilic gel according to claim 2, wherein the concentration of the polyethylene oxide in the hydrogel is about 4 to 35 wt %.

6. A sheet of hydrophilic gel according to claim 2, wherein the concentration of the polyethylene oxide in the hydrogel is about 7 to 20 wt %.

7. A sheet of hydrophilic gel according to claim 2, wherein the polyethylene oxide has a molecular weight of about 0.5 to 5×

10⁶ Daltons.

8. A sheet of hydrophilic gel according to claim 2, wherein the high energy radiation employed to produce the crossslinked polyethylene oxide is a flux of high energy electrons.

9. A sheet of hydrophilic gel according to claim 2, wherein the exposed surface of the sheet is covered by a backing sheet which is peelably removable therefrom.

10. A sheet of hydrophilic gel according to claim 2, wherein the hydrophilic gel contains immersed therein a low area-weight scrim;

wherein the polyethylene oxide has a molecular weight of about 0.5 to 5×

10⁶ Daltons and is present in the hydrophilic gel at a conoentration of about 4 to 12%; and

wherein the exposed sheet which is peelably removable therefrom.

11. A sheet of hydrophilic gel according to claim 10, wherein the scrim formed of a sheet of non-woven polyethylene.

12. A sheet of hydrophilic gel according to claim 1, wherein the hydrophilic gel contains an electrolyte dissolved therein.

13. A sheet of hydrophilic gel according to claim 1, wherein the electrolyte is a water soluble salt present in a concentration of about 0.1 to 15 wt %.

14. A sheet of hydrophilic gel according to claim 13, wherein the water soluble salt is potassium chloride or sodium chloride.