Method for applying an exothermic coating to a substrate

• US 20060141882A1
• Filed: 12/23/2004
• Published: 06/29/2006
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Schorr, Phillip A., Quincy, Roger Bradshaw III
• Granted Patent: US 7,338,516 B2
• Time in Patent Office: Days
• US Class Current: 442/164
• CPC Class Codes: A61F 7/034 Flameless
• CPC Class Codes: C09K 5/18 Non-reversible chemical reactions
• CPC Class Codes: D06N 3/0063 Inorganic compounding ingredients, e.g. metals, carbon fibres, Na2CO3, metal layers; Post-treatment with inorganic compounds
• CPC Class Codes: F24V 30/00 Apparatus or devices using heat produced by exothermal chemical reactions other than combustion
• CPC Class Codes: Y02P 70/62 related technologies for production or treatment of textile or flexible materials or products thereof, including footwear
• CPC Class Codes: Y10T 442/2762 Coated or impregnated natural fiber fabric [e.g., cotton, wool, silk, linen, etc.]
• CPC Class Codes: Y10T 442/2861 Coated or impregnated synthetic organic fiber fabric
• CPC Class Codes: Y10T 442/2926 Coated or impregnated inorganic fiber fabric

Abstract

A substrate that is capable of generating heat upon activation is provided. Specifically, the substrate is applied with an exothermic coating that may be formed from a variety of different components, including oxidizable metals, carbon components, binders, electrolytic salts, moisture-retaining particles, and so forth. The oxidizable metal is capable of undergoing an exothermic reaction in the presence of oxygen and water to generate heat. To reduce the likelihood of premature activation prior to use, the exothermic coating is anhydrous, i.e., generally free of water. The coated substrate may be employed in a wide variety of articles, such as absorbent articles, thermal blankets, drapes, heating pads etc.

Claims

1. A method for applying an exothermic coating to a substrate, said method comprising:

forming a coating formulation that comprises an oxidizable metal powder and a solvent, wherein said solvent constitutes from about 10 wt. % to about 80 wt. % of said coating formulation;

applying said coating formulation to one or more surfaces of the substrate; and

heating said coated substrate to form an exothermic coating that is generally free of water.

2. The method of claim 1, wherein said solvent constitutes from about 20 wt. % to about 70 wt. % of said coating formulation.

3. The method of claim 1, wherein said solvent constitutes from about 25 wt. % to about 60 wt. % of said coating formulation.

4. The method of claim 1, wherein said solvent is water.

5. The method of claim 1, wherein said metal powder contains iron, zinc, aluminum, magnesium, or combinations thereof.

6. The method of claim 1, wherein said metal powder constitutes from about 20 wt. % to about 80 wt. % of said coating formulation.

7. The method of claim 1, wherein said metal powder constitutes from about 30 wt. % to about 70 wt. % of said coating formulation.

8. The method of claim 1, wherein said coating formulation further comprises a carbon component, a binder, and an electrolytic salt.

9. The method of claim 8, wherein said carbon component is activated carbon.

10. The method of claim 8, wherein said binder is a polymer latex, a water-soluble organic polymer, or combination thereof.

11. The method of claim 10, wherein said binder is a nonionic cellulosic ether.

12. The method of claim 8, wherein said electrolytic salt is a metal halide.

13. The method of claim 8, wherein said carbon component constitutes from about 0.1 wt. % to about 20 wt. % of said coating formulation, said binder constitutes from about 0.01 wt. % to about 20 wt. % of said coating formulation, and said electrolytic salt constitutes from about 0.01 wt. % to about 10 wt. % of said coating formulation.

14. The method of claim 1, wherein said coating formulation further comprises moisture-retaining particles.

15. The method of claim 1, wherein the solids content of said aqueous formulation is from about 30% to about 80%.

16. The method of claim 1, wherein the solids content of said aqueous formulation is from about 40% to about 70%.

17. The method of claim 1, wherein said coated substrate is heated at a temperature of at least about 100°

C.

18. The method of claim 1, wherein said coated substrate is heated at a temperature of at least about 110°

C.

19. A substrate that contains an exothermic coating at a solids add-on level of from about 20% to about 5000%, said exothermic coating being formed from an oxidizable metal powder, carbon component, binder, and electrolytic salt, said exothermic coating being capable of activation in the presence of oxygen and moisture to generate heat, wherein said exothermic coating is generally free of water prior to activation.

20. The substrate of claim 19, wherein said metal powder contains iron, zinc, aluminum, magnesium, or combinations thereof.

21. The substrate of claim 19, wherein said carbon component is activated carbon.

22. The substrate of claim 19, wherein said binder is a polymer latex.

23. The substrate of claim 19, wherein said binder is a nonionic cellulosic ether.

24. The substrate of claim 19, wherein said electrolytic salt is a metal halide.

25. The substrate of claim 19, wherein said exothermic coating further comprises moisture-retaining particles.

26. The substrate of claim 25, wherein said moisture-retaining particles include calcium carbonate.

27. The substrate of claim 19, wherein the solids add-on level is from about 100% to about 1200%.

28. The substrate of claim 19, wherein said metal powder constitutes from about 40 wt. % to about 95 wt. % of said exothermic coating.

29. The substrate of claim 19, wherein said metal powder constitutes from about 50 wt. % to about 90 wt. % of said exothermic coating.

30. The substrate of claim 19, wherein said carbon component constitutes from about 0.01 wt. % to about 20 wt. % of said exothermic coating.

31. The substrate of claim 19, wherein said binder constitutes from about 0.01 wt. % to about 20 wt. % of said exothermic coating.

32. The substrate of claim 19, wherein said electrolytic salt constitutes from about 0.01 wt. % to about 10 wt. % of said exothermic coating.

33. The substrate of claim 19, wherein the substrate contains a nonwoven fabric, woven fabric, knit fabric, paper web, film, foam, or combination thereof.

34. The substrate of claim 19, wherein the substrate contains a nonwoven web.