Desiccant entrained polymer

• US 6,130,263 A
• Filed: 03/05/1997
• Issued: 10/10/2000
• Est. Priority Date: 04/19/1995
• Status: Expired due to Term

• Current Assignee: CSP Technologies North America LLC (AptarGroup Incorporated)
• Original Assignee: Capitol Specialty Plastics Incorporated
• Inventors: Hekal, Ihab M.
• Primary Examiner(s): Timm, Catherine
• Assistant Examiner(s): MCDOWELL, SUZANNE E
• Application Number:
  US08/812,315
• Time in Patent Office: 1,315 Days
• Field of Search: 206/204, 34/95, 34/329, 502/402, 502/405, 53/400, 53/428, 53/111, 264/DIG. 78, 264/250, 264/259, 264/510, 264/173.16, 264/268, 264/165, 264/299, 264/176.1, 264/255, 252/194
• US Class Current: 521/50
• CPC Class Codes: B01J 20/28014 characterised by their form
• CPC Class Codes: B01J 20/28033 Membrane, sheet, cloth, pad, lamellar or mat
• CPC Class Codes: B01J 20/28042 Shaped bodies; Monolithic structures
• CPC Class Codes: B29C 45/16 Making multilayered or multicoloured articles B29C45/0062 takes precedence; feeding colouring materials into the injection unit B29C45/1816
• CPC Class Codes: B65D 81/264 for absorbing liquids
• CPC Class Codes: B65D 81/266 for absorbing gases, e.g. oxygen absorbers or desiccants B65D51/244, B65D51/30 take precedence
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
• CPC Class Codes: Y10S 264/78 Processes of molding using vacuum
• CPC Class Codes: Y10S 521/905 Hydrophilic or hydrophobic cellular product

Abstract

The present invention includes processes and resulting structures for producing moisture absorbing desiccant entrained polymers. A polymer is caused to assume a molten state, typically by applying heat and melting the polymer. To achieve certain results in the hardened end product, such as rigidity and durability, the polymer normally acts as a moisture barrier in a solidified state, both before and after melting. A desiccating agent is blended into the polymer so that the desiccating agent is distributed within the polymer. A channeling agent is also blended into the polymer so that it is distributed within the polymer. The blending of the components is preferably done before the polymer is caused to assume a molten state. Together, the polymer, desiccating agent and channeling agent create a blended mixture. The mixture is solidified so that the channeling agent forms passages in the mixture through which moisture is communicable to desiccating agent that is entrained within the mixture. The solidified mixture may be used to form plug type inserts and liners for closed containers, or it may be used for producing laminated sheeting employed as package wrap.

Claims

1. An article of manufacture comprising a shaped article formed by:

(a) mixing a polymer, a desiccating agent and a channeling agent, wherein the channeling agent is a hydrophilic material;

(b) heating the mixture at a temperature at least above the melt point of the channeling agent so that the desiccating agent and channeling agent are distributed within the polymer;

(c) cooling the mixture to form passages containing the channeling agent through which moisture is communicable with the desiccating agent.

3. The article of claims 1 or 2 wherein the polymer is a thermoplastic.

4. The article of claim 3, wherein the desiccating agent is selected from the group consisting of silica gel, molecular sieve and clay.

5. The article of claims 1 or 2 wherein the channeling agent is selected from the group of a polyglycol, glycerin, ethylene-vinyl alcohol and polyvinyl alcohol.

6. The article of claims 1 or 2 wherein the desiccating agent is of the type that physically absorbs moisture, is inert and non-water soluble.

7. The article of claims 1 or 2 further comprising;

forming a plug from the mixture for inclusion within a container constructed of a substantially moisture impermeable barrier material.

8. The article of claim 7, wherein the article is a container.

9. The article of claims 1 or 2 further comprising:

forming a liner with the mixture for inclusion within a container constructed from a substantially moisture impermeable barrier substance, the liner having an exterior surface configured for mating engagement with an interior surface of the container.

10. The article of claims 1 or 2 further comprising:

molding a liner from the mixture; and

molding a container from a moisture barrier substance about the liner so that at least a portion of the liner is exposed to an interior of the container and a majority of an interior surface of the container is covered by the liner.

11. The article of claims 1 or 2, wherein the article is in the form of a disc.

12. The article of claims 1 or 2, wherein the article is in the form of a film.

13. The article of claims 1 or 2, wherein the article is in the form of a sleeve.

14. The article of claims 1 or 2, wherein the article is in the form of beads.

15. The article of claims 1 or 2, wherein the article is in the form of a sheet.

16. The article of claims 1 or 2, wherein the article is molded into a shaped article.

17. The article of claims 1 or 2, wherein the article is extruded into a shaped article.

2. An article of manufacture comprising a shaped article formed by:

(a) heating a polymer;

(b) mixing a desiccating agent and a channeling agent with the polymer material at a temperature at least above the melt point of the channeling agent, wherein the channeling agent is a hydrophilic material; and

(c) cooling the blend to form passages containing the channeling agent through which moisture is communicable with the desiccating agent.

18. An article of manufacture comprising a monolithic composition formed by:

(a) mixing a polymer, a desiccating and a channeling agent, wherein the channeling agent is a hydrophilic material;

(b) heating the mixture at least above the melt point of the channeling agent so that the desiccating agent and channeling agent are distributed within the polymer; and

(c) cooling the mixture to form channels containing the channeling agent.

19. An article of manufacture comprising a monolithic composition formed by:

(a) mixing a polymer selected from the group consisting of polyolefins, polycarbonates and polyamides;

a desiccating agent selected from the group consisting of silica gel, molecular sieve and clay; and

a channeling agent selected from the group consisting of polyglycol, glycerin, ethylene-vinyl alcohol and polyvinyl alcohol;

(b) heating the mixture at least above the melt point of the channeling agent so that the desiccating agent and channeling agent are distributed within the polymer; and

(c) cooling the mixture to form a monolithic composition.

20. An article of manufacture comprising a monolithic composition formed by:

(a) mixing a polymer, a desiccating agent and a channeling agent, wherein the channeling agent is a hydrophilic material;

(b) exposing the mixture to a temperature at least above the melt point of the channeling agent so that the desiccating agent and channeling agent are distributed within the polymer; and

(c) forming a monolithic composition having channels containing the channeling agent.

21. The article of claim 20, wherein:

(a) the polymer is selected from the group consisting of polyolefins, polycarbonates and polyamides;

(b) the desiccating agent is selected from the group consisting of silica gel, molecular sieve, and clay; and

(c) the channeling agent is selected from the group consisting of polyglycol, glycerin, ethylene-vinyl alcohol and polyvinyl alcohol.

22. An article of manufacture comprising a monolithic composition formed by:

(a) mixing a polymer, a desiccating agent and a channeling agent, wherein the channeling agent is a hydrophilic material;

(b) exposing the mixture to a temperature at least above the melt point of the channeling agent so that the desiccating agent and the channeling agent are distributed within the polymer; and

(c) cooling the mixture to form a monolithic composition having channels containing the channeling agent.

23. The article of claim 22, wherein the article is in a form of a sheet.

24. The article of claim 22, wherein the article is extruded into a shaped article.

25. The article of claim 22, wherein the desiccating agent is selected from the group consisting of a silica gel, molecular sieve and clay.

26. The article of claim 22, wherein the article is a container.

27. The article of claim 22, wherein the polymer is a thermoplastic.

28. The article of claim 22, wherein the channeling agent is selected from the group consisting of a polyglycol, glycerin, ethylene-vinyl alcohol and polyvinyl alcohol.

29. The article of claim 22, wherein the article is in the form of a disc.

30. The article of claim 22, wherein the article is in the form of a film.

31. The article of claim 22, wherein the article is in a form of a sleeve.

32. The article of claim 22, wherein the article is in a form of beads.