Curable resin coated sheets having reduced tack

• US 4,856,502 A
• Filed: 05/22/1987
• Issued: 08/15/1989
• Est. Priority Date: 05/05/1987
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Reed, Katherine E., Scholz, Matthew T., Hansen, Paul E., Buckanin, Richard S., Ersfeld, Dean A., Bartizal, Dennis C., Larson, Wayne K., Sandvig, Timothy C.
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): PREBILIC, PAUL B
• Application Number:
  US07/053,098
• Time in Patent Office: 816 Days
• Field of Search: 128/89 R, 128/90, 128/91 R, 128/155, 128/156, 128/169, 427/2, 428/253, 428/290, 428/352, 428/423.1, 428/423.7, 428/425.6, 428/913
• US Class Current: 602/8
• CPC Class Codes: A61F 13/04 Plaster of Paris bandages; Other stiffening bandages A61F13/06 - A61F13/15 take precedence
• CPC Class Codes: A61L 15/07 Stiffening bandages
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31601 Quartz or glass
• CPC Class Codes: Y10T 442/172 Coated or impregnated
• CPC Class Codes: Y10T 442/198 Coated or impregnated
• CPC Class Codes: Y10T 442/2311 Coating or impregnation is a lubricant or a surface friction reducing agent other than specified as improving the "hand" of the fabric or increasing the softness thereof
• CPC Class Codes: Y10T 442/2328 Organosilicon containing

Abstract

The present invention relates to orthopedic casting materials having reduced tack and methods for preparing and using such orthopedic casting materials, wherein the materials comprise a nonwoven, stretchable fabric which is impregnated with a curable prepolymer resin. The nonwoven fabric comprises fiber bundles and apertures between the fiber bundles, with each of the fiber bundles comprising a plurality of fibers having interstices therebetween. The curable prepolymer resin is impregnated into the nonwoven fabric such that the interstices between the fibers receive the resin, while leaving the apertures between fiber bundles substantially unoccluded. Such orthopedic casting materials are relatively inexpensive and exhibit improved properties.

Claims

1. An orthopedic support material, comprising a nonwoven, stretchable fabric impregnated with a pre-lubricated curable resin:

wherein a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2;

wherein said nonwoven fabric comprises a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween, the average cross-sectional area of each said fiber bundle being from about 0.2 mm² to about 1.2 mm² ; and

wherein said resin is impregnated into the interstices between said fibers of said fiber bundles so as to impart sufficient strength to the material upon curing to be used as an orthopedic support material while leaving the apertures between fiber bundles substantially unoccluded so as to permit sufficient water vapor permeability through the cured material.

2. An orthopedic support material as defined in claim 1 wherein, prior to impregnation with said resin, said nonwoven fabric has from about 10% to about 45% extensibility in the elongated direction when a 2 pound load is applied across a 1.5 inch section of the nonwoven fabric.

3. An orthopedic support material as defined in claim 1 wherein the fibers in each said fiber bundle are oriented so as to be generally parallel to one another.

4. An orthopedic support material as defined in claim 1 wherein a cross-section of each said fiber bundle contains an average of at least about 100 of said fibers.

5. An orthopedic support material as defined in claim 1 wherein the average diameter of each individual fiber in each said fiber bundle is from about 1 micron to about 30 microns.

6. An orthopedic support material as defined in claim 1 wherein the average void volume within each said fiber bundle is from about 20% to about 98% of the total volume occupied by the fiber bundle.

7. An orthopedic support material as defined in claim 1 wherein the weight of said nonwoven fabric is from about 1 ounce per square yard to about 2.5 ounces per square yard.

8. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric has from about 15 to about 400 of said apertures per square inch.

9. An orthopedic support material as defined in claim 1 wherein the average size of said apertures is from about 0.3 mm² to about 16 mm².

10. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric is a spunlaced, hydroentangled, nonwoven fabric.

11. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises polyester.

12. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises cotton.

13. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises nylon.

14. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises acrylic.

15. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises polypropylene.

16. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises fiberglass.

17. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises polyarylamide.

18. An orthopedic support material as defined in claim 1 wherein said nonwoven fabric comprises carbon.

19. An orthopedic support material as defined in claim 1 wherein said resin is an isocyanate functional, polyurethane prepolymer resin.

20. An orthopedic support material as defined in claim 1 wherein sufficient resin is impregnated into the nonwoven fabric such that the resin represents from about 65% to about 90% by weight of the total weight of the orthopedic support material.

21. An orthopedic support material as defined in claim 1 wherein from about 0.1 grams to about 0.3 grams of resin are applied to each square inch of the nonwoven fabric.

22. An orthopedic support material as defined in claim 1 wherein from about 60% to about 100% of the total area of said apertures remains unoccluded after impregnation of said resin into said nonwoven fabric.

23. An orthopedic support material as defined in claim 1 wherein upon curing a laminate comprising 6 layers of said material said laminate has a passive water vapor permeability of at least about 2000 mg H₂ O vapor/m² -hr when measured under an atmosphere of about 45% relative humidity and at a temperature of about 22°

C.

24. An orthopedic support material as defined in claim 1 wherein upon curing a laminate comprising 6 layers of said material, with each layer having an area of about 4 in², said laminate has an air permeability of from about 30 cm³ air/second to about 370 cm³ air/second when an air pressure differential of about 6.4 psi exists between two sides of the laminate.

25. An orthopedic support material as defined in claim 1 wherein after curing a ring laminate comprising 6 layers of said material and having a length of 3 inches and a diameter of 2 inches, said ring laminate has a ring strength of at least about 10 pounds per inch of ring length.

26. An orthopedic support material as defined in claim 1 wherein said prelubricated curable resin comprises a lubricant at the major surface of the material, said lubricant comprising

(a) hydrophilic groups which are covalently bonded to the curable resin, or

(b) an additive which is incompatible with the curable resin, or

(c) a combination of (a) and (b);

and wherein said lubricant is present in an amount such that the kinetic coefficient of friction of the major surface of the material is less than about 1.2.

27. An orthopedic support material as defined in claim 26 wherein the lubricant comprises hydrophilic groups which are covalently bonded to the curable resin.

28. An orthopedic support material as defined in claim 27 wherein the lubricant comprises polyethylene oxide.

29. An orthopedic support material as defined in claim 27 wherein the lubricant comprises a polyethoxylated fatty alcohol.

30. An orthopedic support material as defined in claim 29 wherein the lubricant comprises sulfonate groups.

31. An orthopedic support material as defined in claim 28 wherein said lubricant is an additive which comprises a surfactant.

32. An orthopedic support material as defined in claim 31 wherein said surfactant is an alkyl, aryl, or aralkyl ionic compound.

33. An orthopedic support material as defined in claim 31 wherein said surfactant is an alkyl sulfate.

34. An orthopedic support material as defined in claim 31 wherein said surfactant is a polyethoxylated compound.

35. An orthopedic support material as defined in claim 31 wherein said surfactant is an anionic compound.

36. An orthopedic support material as defined in claim 31 wherein said surfactant is a nonionic compound.

37. An orthopedic support material as defined in claim 31 wherein said surfactant is a solid at ambient temperatures.

38. An orthopedic support material as defined in claim 26 wherein said lubricant is an additive which comprises a polymer having a plurality of hydrophilic groups.

39. An orthopedic support material as defined in claim 38 wherein said polymer is comprised of repeating units derived from ethylenically unsaturated monomers selected from the group consisting of acrylamide, vinylpyrrolidone, vinylacetate and its polymeric hydrolyzed derivatives, hydroxy and amino functional lower alkyl acrylates, and combinations thereof.

40. An orthopedic support material as defined in claim 38 wherein said polymer is polyvinyl alcohol.

41. An orthopedic support material as defined in claim 26 wherein said lubricant is an additive which comprises a polysiloxane.

42. An orthopedic support material as defined in claim 26 wherein said lubricant is an additive which comprises a polydimethylsiloxane.

43. An orthopedic support material as defined in claim 26 wherein said lubricant is an additive comprising a mixture of any of the compositions selected from the group consisting of:

(i) a surfactant;

(ii) a polymer having a plurality of hydrophilic groups; and

(iii) a polysiloxane.

50. An orthopedic support material as defined in claim 1 wherein said major surface of the material exhibits a kinetic coefficient of friction of 0.93 or less.

51. An orthopedic support material as defined in claim 1 wherein said major surface of the material exhibits a kinetic coefficient of friction of 0.75 or less.

52. An orthopedic support material as defined in claim 1 wherein said major surface of the material exhibits a kinetic coefficient of friction of 0.4 or less.

44. An orthopedic casting material comprising a nonwoven sheet of polyester impregnated with a pre-lubricated, isocyanate functional, polyurethane prepolymer resin:

wherein a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2;

wherein said nonwoven sheet of polyester comprises a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween, the average cross-sectional area of each said fiber bundle being from about 0.2 mm² to about 1.2 mm², said nonwoven polyester sheet having from about 10% to about 45% extensibility along its length when a 2 pound force is applied across a 1.5 inch section of said sheet; and

wherein said pre-lubricated, isocyanate functional, polyurethane prepolymer resin is impregnated into the interstices between said fibers of said fiber bundles in sufficient quantity such that the resin represents from about 65% to about 90% by weight of the total weight of the orthopedic casting material and imparts sufficient strength to the material upon curing to be used as an orthopedic casting material, said apertures remaining substantially unoccluded such that upon curing a laminate comprising 6 layers of said material said laminate has a water vapor permeability of at least about 2000 mg H₂ O vapor/m² -hr when measured under an atmosphere of about 45% relative humidity and at a temperature of about 22°

C., thereby substantially avoiding skin maceration.

45. An orthopedic casting material as defined in claim 44:

wherein the fibers in each said fiber bundle are oriented so as to be generally parallel to one another and wherein a cross-section of each said fiber bundle contains an average of at least about 100 of said fibers;

wherein said nonwoven polyester sheet has a weight of from about 1 ounce per square yard to about 2.5 ounces per square yard; and

wherein said nonwoven polyester sheet has from about 15 to about 400 of said apertures per square inch, the average size of said apertures ranging from about 0.3 mm² to about 16 mm².

46. A method of preparing an orthopedic support material, comprising the steps of:

providing a nonwoven, stretchable fabric comprising a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween, the average cross-sectional area of each said fiber bundle being from about 0.2 mm² to about 1.2 mm² ; and

impregnating a curable resin into the interstices between the fibers of the fiber bundles so as to impart sufficient strength to the material upon curing to be used as an orthopedic support material while leaving the apertures between fiber bundles substantially unoccluded so as to permit sufficient water vapor permeability through the cured material, said curable resin being pre-lubricated such that, prior to the completion of curing, a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2.

47. An orthopedic support material, comprising a nonwoven, stretchable fabric impregnated with a pre-lubricated curable resin:

wherein a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2;

wherein said nonwoven fabric comprises a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween, the weight of said nonwoven fabric being from about 1 ounce per square yard to about 2.5 ounces per square yard; and

wherein said resin is impregnated into the interstices between said fibers of said fiber bundles so as to impart sufficient strength to the material while leaving the apertures between fiber bundles substantially unoccluded so as to permit sufficient water vapor permeability through the cured material.

48. An orthopedic support material, comprising a nonwoven, stretchable fabric impregnated with a pre-lubricated curable resin:

wherein a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2;

wherein said nonwoven fabric comprises a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween;

wherein said resin is impregnated into the interstices between said fibers of said fiber bundles so as to impart sufficient strength to the material upon curing to be used as an orthopedic support material while leaving the apertures between fiber bundles substantially unoccluded so as to permit sufficient water vapor permeability through the cured material; and

wherein upon curing laminate comprising 6 layers of said material said laminate has a passive water vapor permeability of at least about 2000 mg H₂ O vapor/m² -hr when measured under an atmosphere of about 45% relative humidity and at a temperature of about 22°

C.

49. An orthopedic support material, comprising a nonwoven, stretchable fabric impregnated with a pre-lubricated curable resin:

wherein a major surface of the material exhibits a kinetic coefficient of friction of less than about 1.2;

wherein said nonwoven fabric comprises a pattern of fiber bundles and apertures between said fiber bundles, each said fiber bundle comprising a plurality of fibers having interstices therebetween;

wherein said resin is impregnated into the interstices between said fibers of said fiber bundles so as to impart sufficient strength to the material upon curing to be used as an orthopedic support material while leaving the apertures between fiber bundles substantially unoccluded so as to permit sufficient water vapor permeability through the cured material; and

wherein upon curing a laminate comprising 6 layers of said material, with each layer having an area of about 4 in², said laminate has an air permeability of from about 30 cm³ air/second to about 370 cm³ air/second when an air pressure differential of about 6.4 psi exists between two sides of the laminate.