US4098940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermoplastics sheets or composite sheets with optical inhomogeneities
Assignee: Hoechst AG
•
Filing: 1976-08-31
•
Granted: 1978-07-04
•
Expires: 1996-08-31
Abstract
Abstract The present invention is related to a sheet or a composite sheet made of transparent thermoplastics with optical inhomogeneities according to a desired and reproducible pattern, which are not discernible with an unaided eye, and which produce polarization-optical patterns when placed in a polarization-optical arrangement. The invention is further related to a process for the manufacture of such a sheet or composite sheet and to their use for the manufacture of counterfeit-proof official documents.
Inventors
- 👤 Rudolf Groh
- 👤 Gustav Meinel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:56
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/12; B29; B29C; B29C67/00; B32B27/30; B32B27/304; B32B27/36; G; G09; G09F; G09F3/00; G09F3/02; G09F3/0291; G09F3/0294; B32B2307/00; B32B2307/40; B32B2307/41; Y; Y10; Y10S; Y10S428/00; Y10S428/914; Y10S428/915; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24992; Y10T428/31504; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
Transparent sheet consisting of a vinyl chloride or styrene polymer, said sheet having optical inhomogeneities which become visible as optical patterns when the sheet is placed between two crossed polarization filters, said optical inhomogeneities being obtained by producing in said sheet thicker spots according to a desired pattern, which spots protrude from the sheet surface 20 to 300 μm at a temperature within the liquid-viscous range of the polymer, and subjecting the patterned sheet to compression at a temperature within the rubber-elastic range to obtain a smooth sheet for achieving optical inhomogeneities.
Claim 2
Dependent Claim
92 words
Transparent sheet consisting of a vinyl chloride or styrene polymer, said sheet having optical inhomogeneities which become visible as optical patterns when the sheet is placed between two crossed polarization filters, said optical inhomogeneities being obtained by producing in said sheet thicker spots according to a desired pattern, which spots protrude from the sheet surface 20 to 300 μm at a temperature within the liquid-viscous range of the polymer, and subjecting the patterned sheet to compression at a temperature within the rubber-elastic range to obtain a smooth sheet for achieving optical inhomogeneities.
Claim 3
Dependent Claim
9 words
Counterfeit-proof documents containing a sheet according to claim 1.
Claim 4
Dependent Claim
10 words
Information carriers consisting of a sheet according to claim 1.
Claim 5
Dependent Claim
12 words
Compounds of various sheets, which contain a sheet according to claim 1.
Claim 6
Dependent Claim
12 words
Compounds of sheets and paper containing a sheet according to claim 1.
Claim 7
Dependent Claim
132 words
Transparent sheet consisting of a vinyl chloride or styrene polymer, said sheet having optical inhomogeneities which become visible as optical patterns when the sheet is placed between two crossed polarization filters, said optical inhomogeneities being produced by compressing the sheet together with a latticed sheet of a homopolymer of vinyl chloride or a copolymer thereof with at least 85 weight percent, calculated on the polymer of polymerized vinyl chloride, said latticed sheet having a thickness surpassing at least by 5% the thickness of the sheet to be compressed with it and having projections according to a predetermed pattern, said compression being carried out at a temperature within the rubber-elastic temperature range of the polymer to thereby obtain a smooth sheet in which the pattern of the lattice is transmitted as optical inhomogeneities.
Claim 8
Dependent Claim
132 words
Transparent sheet consisting of a vinyl chloride or styrene polymer, said sheet having optical inhomogeneities which become visible as optical patterns when the sheet is placed between two crossed polarization filters, said optical inhomogeneities being produced by compressing the sheet together with a latticed sheet of a homopolymer of vinyl chloride or a copolymer thereof with at least 85 weight percent, calculated on the polymer of polymerized vinyl chloride, said latticed sheet having a thickness surpassing at least by 5% the thickness of the sheet to be compressed with it and having projections according to a predetermed pattern, said compression being carried out at a temperature within the rubber-elastic temperature range of the polymer to thereby obtain a smooth sheet in which the pattern of the lattice is transmitted as optical inhomogeneities.
Claim 9
Dependent Claim
9 words
Counterfeit-proof documents containing a sheet according to claim 6.
Claim 10
Dependent Claim
10 words
Information carriers consisting of a sheet according to claim 6.
Claim 11
Dependent Claim
12 words
Compounds of various sheets which contain a sheet according to claim 6.
Claim 12
Dependent Claim
12 words
Compounds of sheets and paper containing a sheet according to claim 6.
References Cited (Backward Citations)
US3412493A
Cited
US3655494A
Cited
US3610120A
Cited
US3679448A
Cited
US3679449A
Cited
US3919447A
Cited
US3961956A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |