Monolithic composition having the capability of maintaining constant relative humidity in a package

• US 6,613,405 B1
• Filed: 03/30/2001
• Issued: 09/02/2003
• Est. Priority Date: 04/19/1995
• Status: Expired due to Term

• Current Assignee: CSP Technologies North America LLC (AptarGroup Incorporated)
• Original Assignee: CSP Technologies Incorporated (AptarGroup Incorporated)
• Inventors: Hekal, Ihab M.
• Primary Examiner(s): McDowell, Suzanne E.
• Application Number:
  US09/823,355
• Time in Patent Office: 886 Days
• Field of Search: 428/34.1, 428/35.7, 428/613, 206/204, 34/95, 343/29, 534/00, 534/28, 531/11, 252/194
• US Class Current: 428/34.1
• 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: F26B 21/083 by using sorbent or hygroscopic materials, e.g. chemical substances, molecular sieves
• CPC Class Codes: Y10T 428/12479 Porous [e.g., foamed, spongy, cracked, etc.]
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]

Abstract

The present invention generally related to a monolithic composition comprising a water insoluble polymer and a deliquescent material. A deliquescent material is blended into the polymer so that the deliquescent material is distributed within the product. The deliquescent material blended in the water-insoluble polymer is capable of maintaining a substantially constant relative humidity in a closed container. The product may be used to form a desired shaped article such as plug type inserts and liners for closed containers, or it may be formed into a film, sheet, bead or pellet.

Claims

1. An article of manufacture comprising a monolithic composition for maintaining a substantially constant relative humidity formed by combining at least the following components:

a polymer having a solubility in water below about 0.1% at 25°

C. and atmospheric pressure;

a hydrophilic agent is at least about 5% by weight of the polymer and is selected from the group consisting of polyglycols, poly(ethylene glycol), poly(propylene glycol), EVOH, pentaerithritol, PVOH, polyvinylpyrollidine, vinylpyrollidone or poly(N-methyl pyrollidone), and saccharide based compounds, glucose, fructose, and their alcohols, mannitol, dextrin, and hydrolized starch and mixtures thereof; and

a deliquescent material;

wherein the composition comprises at least three phases and has interconnecting channels with the deliquescent material in or adjacent to these channels.

2. An article of manufacture comprising a monolithic composition for maintaining a substantially constant relative humidity comprising at least the following components:

(a) a polymer having a solubility in water below about 0.1% at 25°

C. and atmospheric pressure;

(b) a hydrophilic agent is at least about 5% by weight of the polymer and is selected from the group consisting of polyglycols, poly(ethylene glycol), poly(propylene glycol), EVOH, pentaerithritol, PVOH, polyvinylpyrollidine, vinylpyrollidone or poly(N-methyl pyrollidone), and saccharide based compounds, glucose, fructose, and their alcohols, mannitol, dextrin, and hydrolized starch and mixtures thereof; and

(c) a deliquescent material;

wherein the composition comprises at least three phases and has interconnecting channels with the releasing agent in or adjacent to these channels.

3. The article of manufacture of claim 2 wherein the polymer is a thermoplastic.

4. The article of manufacture of claim 2 wherein the hydrophilic agent is a polyglycol.