Desiccant entrained polymer

• US 6,214,255 B1
• Filed: 07/27/1998
• Issued: 04/10/2001
• 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): Silbaugh, Jan H.
• Assistant Examiner(s): McDowell, Suzanne E
• Application Number:
  US09/122,912
• Time in Patent Office: 988 Days
• Field of Search: 206/204, 34/95, 343/29, 502/402, 502/405, 534/00, 534/28, 531/11, 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: 252/194
• CPC Class Codes: B01J 20/28042 Shaped bodies; Monolithic structures
• CPC Class Codes: B29C 45/006 Joining parts moulded in separate cavities
• CPC Class Codes: B29C 45/0081 of objects with parts connected by a thin section, e.g. hinge, tear line
• 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: B29L 2031/565 for containers
• CPC Class Codes: B65D 81/266 for absorbing gases, e.g. oxygen absorbers or desiccants B65D51/244, B65D51/30 take precedence

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. 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. The composition having veined domains of channeling agents comprising at least three components:

(a) wherein component A is a polyolefin;

(b) wherein component B is a channeling agent consisting of a hydrophilic material that is heated above its melt point during processing of the composition;

(c) wherein component B is substantially separate from component A and forms channels;

(d) wherein component C is a desiccating agent;

(e) wherein the volume fraction of component A represents at least about 50% by volume of the total volume of components A, B and C;

(f) wherein the preferential affinity between component B and component C is greater than between components A, and component C;

(g) wherein at least two aggregates are formed, one aggregate is composed of a majority of components A, and the second aggregate is composed of a majority of component B and a majority of component C; and

(h) wherein component B forms channels for moisture transmission through the polymer.

2. The composition of claim 1 wherein the polyolefin is selected from the group consisting of polyethylene and polypropylene.

3. The composition of claim 1 wherein the desiccating agent is selected from the group consisting of silica gel and molecular sieve.

4. The composition of claim 1, wherein the composition is formed into a shaped article.

5. The composition of claim 4, wherein the shaped article is a sheet for use as a packaging wrap.

6. The composition of claim 1, wherein the range of desiccating agent is between about 40% to about 60% by weight of the total composition.