Moisture and particle getter for enclosures

• US 5,304,419 A
• Filed: 03/09/1992
• Issued: 04/19/1994
• Est. Priority Date: 07/06/1990
• Status: Expired due to Term

• Current Assignee: Alpha Fry Limited (Element Solutions Inc)
• Original Assignee: Staystik Incorporated
• Inventors: Shores, A. Andrew
• Primary Examiner(s): ZIRKER, DANIEL R
• Application Number:
  US07/848,232
• Time in Patent Office: 771 Days
• Field of Search: 252/194, 428/355, 428/343, 428/351, 55/387, 55/389
• US Class Current: 428/355.00R
• CPC Class Codes: C09K 2200/0243 Silica-rich compounds, e.g. silicates, cement, glass
• CPC Class Codes: C09K 2200/06 Macromolecular organic compounds, e.g. prepolymers
• CPC Class Codes: C09K 3/1018 Macromolecular compounds having one or more carbon-to-silicon linkages
• CPC Class Codes: H05K 5/0212 Condensation eliminators
• CPC Class Codes: H05K 5/0213 Venting apertures; Constructional details thereof
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/846 comprising getter material or desiccants
• CPC Class Codes: Y10S 95/902 Molecular sieve
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2835 including moisture or waterproof component
• CPC Class Codes: Y10T 428/2852 Adhesive compositions
• CPC Class Codes: Y10T 428/2891 including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof
• CPC Class Codes: Y10T 428/2896 including nitrogen containing condensation polymer [e.g., polyurethane, polyisocyanate, etc.]

Abstract

An enclosure for providing both a moisture free and particle free environment is disclosed. A portion of the inner surface of the enclosure, that comprises an electronic device sealed in a container, is coated with a pressure sensitive adhesive comprising 4-40 percent, by volume, of a solid desiccant. The preferred adhesive is a silicone pressure sensitive adhesive and the preferred desiccant is zeolite.

Claims

1. A hermetically sealed enclosure housing an electronic device and having an inner surface provided on at least some portion thereof with a coating of a pressure sensitive adhesive containing 4-40 volume percent of a finely particulated solid desiccant having an average particle size of 0.2-100 micrometer, said coating having a thickness of 1-25 mil and being effective to maintain an environment within the enclosure substantially moisture-free and substantially devoid of free solid particles.

2. An enclosure as in claim 1 wherein said desiccant is a zeolite.

3. An enclosure as in claim 1 wherein said desiccant is selected from the group consisting of activated alumina, silica gel, calcium sulfate, calcium chloride, calcium bromide and lithium chloride.

4. An enclosure as in claim 1 wherein said desiccant is selected from the group consisting of an alkaline earth oxide, potassium carbonate, copper sulfate, zinc chloride and zinc bromide.

5. An enclosure as in claim 1 wherein said pressure sensitive adhesive is a silicone.

6. An enclosure as in claim 5, wherein said desiccant is a zeolite.

7. An enclosure as in claim 1, wherein said pressure sensitive adhesive is selected from the group consisting of acrylics, polyvinylethers, polyurethanes and rubber-tackifier mixtures.

8. An enclosure as in claim 1, wherein the coating thickness is 2-10 mil.

9. An enclosure as in claim 8, wherein the average particle size is 0.5-10 micrometer.

10. An enclosure as in claim 1, wherein the average particle size is 0.5-10 micrometer.

11. A hermetically sealed enclosure housing an electronic device and having an inner surface at least some portion of which is provided with a coating of a pressure sensitive adhesive which is effective to maintain an environment within the enclosure substantially devoid of free solid particulate contaminants, said coating having a thickness of 1-25 mil and containing a finely particulated solid desiccant having an average particle size of 0.2-100 micrometer in an amount effective to maintain said environment substantially moisture-free.

12. An enclosure as in claim 11, wherein the coating thickness is 2-10 mil.

13. An enclosure as in claim 11, wherein the average particle size is 0.5-10 micrometer.

14. An enclosure as in claim 13, wherein said coating has a thickness of 2-10 mil.