US5663227A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Release agent for linerless pressure sensitive postage stamps
Assignee: United States Postal Service
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Filing: 1996-03-14
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Granted: 1997-09-02
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Expires: 2016-03-14
Abstract
Abstract An improved release agent for linerless pressure sensitive postage stamps, comprising a low adhesion backsize, preferably organo polysiloxane polyurea block copolymer, as disclosed by Tushaus, et al. (U.S. Pat. No. 5,290,615), containing therein a dispersion of calcium carbonate in the range of 2 to 7 percent by weight, and polyvinyl pyrrolidone in the range of 4 to 10 percent. The combined level of both additives to said low adhesion backsize is about 8 to 12 percent. The preferred levels of each additive are: polyvinyl pyrrolidone at 4 percent and calcium carbonate at 4 percent, to achieve a desired minimum drying time for cancellation ink imposed upon a surface of said release agent.
Inventors
- 👤 Ronald B. Birkholz
- 👤 Mark E. Schwartz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:53
CPC Classifications
G; G09; G09F; G09F3/00; G09F3/08; G09F3/10; C; C09; C09D; C09D183/00; C09D183/10; Y; Y10; Y10T; Y10T428/00; Y10T428/14; Y10T428/1476
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
A release agent for covering an upper, image-bearing surface of each of an aggregate of linerless, pressure sensitive postage stamps, said stamps being connected end-to-end and coiled into a roll, with pressure sensitive adhesive of one stamp removably adhering to said release agent stop a stamp in another layer of said roll, said release agent comprising: (a) an organo polysiloxane polyurea block copolymer with average molecular weight of about 4780; (b) calcium carbonate dispersed throughout said copolymer: and (c) polyvinyl pyrrolidone dispersed throughout said copolymer, whereby said release agent may accept and retain a glycol-based postal cancellation ink.
Claim 2
Dependent Claim
98 words
A release agent for covering an upper, image-bearing surface of each of an aggregate of linerless, pressure sensitive postage stamps, said stamps being connected end-to-end and coiled into a roll, with pressure sensitive adhesive of one stamp removably adhering to said release agent stop a stamp in another layer of said roll, said release agent comprising: (a) an organo polysiloxane polyurea block copolymer with average molecular weight of about 4780; (b) calcium carbonate dispersed throughout said copolymer: and (c) polyvinyl pyrrolidone dispersed throughout said copolymer, whereby said release agent may accept and retain a glycol-based postal cancellation ink.
Claim 3
Dependent Claim
48 words
A release agent as described in claim 1, wherein said calcium carbonate is dispersed within said copolymer at a level of 2 to 7 percent of total weight, and said polyvinyl pyrrolidone is dispersed within said copolymer at a level of 4 to 10 percent of total weight.
Claim 4
Dependent Claim
29 words
A release agent as described in claim 2, wherein said calcium carbonate and said polyvinyl pyrrolidone appear at a total combined level of about 8 percent of total weight.
Claim 5
Dependent Claim
36 words
A release agent as described in claim 3, wherein said calcium carbonate appears at a level of 4 percent of total weight and said polyvinyl pyrrolidone appears at a level of 4 percent of total weight.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-09-01 | 2001-03-03 | 2001-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-01 | 2005-03-03 | 2005-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-01 | 2009-03-03 | 2009-09-02 | $7700.00 | Window Closed / Lapsed |