Patent US5894022A successfully refreshed from Google Patents.
Patent US4664966A successfully refreshed from Google Patents.
US4664966A
Expired / Lapsed
US
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Enclosed-lens retroreflective sheeting having tough, weather-resistant, transparent cover film
Assignee: 3M Co
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Filing: 1985-11-18
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Granted: 1987-05-12
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Expires: 2005-11-18
Abstract
Abstract A transparent cover film better protects enclosed-lens retroreflective sheeting and can be applied more economically when it is extruded and is a thermoplastic polymer which has good elongation and minimal elastic memory. Preferred polymers are (a) aliphatic urethanes and (b) copolymers of ethylene or propylene.
Inventors
- 👤 Terry R. Bailey
- 👤 Dale H. Haunschild
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:49
CPC Classifications
B; B32; B32B; B32B5/00; B32B5/16; B32B27/00; B32B27/06; B32B27/08; G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T428/24868; Y10T428/24876; Y10T428/25; Y10T428/252
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
72 words
Enclosed-lens retroreflective sheeting comprising substantially a monolayer of lenses anchored in a binder layer, a specularly reflective layer underlying and spaced from the lenses by transparent material, and a weather-resistant, transparent cover film, wherein the improvement comprises: the cover film comprises extruded, substantially thermoplastic polymer and has an elongation of at least 50% and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 2300 N/m width.
Claim 2
Dependent Claim
72 words
Enclosed-lens retroreflective sheeting comprising substantially a monolayer of lenses anchored in a binder layer, a specularly reflective layer underlying and spaced from the lenses by transparent material, and a weather-resistant, transparent cover film, wherein the improvement comprises: the cover film comprises extruded, substantially thermoplastic polymer and has an elongation of at least 50% and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 2300 N/m width.
Claim 3
Dependent Claim
29 words
Retroreflective sheeting as defined in claim 1 wherein the cover film has an elongation of at least 100% and a tensile relaxation force of less than 1000 N/m width.
Claim 4
Dependent Claim
25 words
Retroreflective sheeting as defined in claim 2 wherein the elongation is at least 200% and the tensile relaxation force is less than 700 N/m width.
Claim 5
Dependent Claim
19 words
Retroreflective sheeting as defined in claim 1 wherein the melt index of the polymer is no greater than 300.
Claim 6
Dependent Claim
48 words
Retroreflective sheeting as defined in claim 1 wherein the polymer is selected from (a) one or more aliphatic urethanes or (b) one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer.
Claim 7
Dependent Claim
30 words
Retroreflective sheeting as defined in claim 5 wherein the polymer is a copolymer (b), and said another monomer is at least one of acrylic acid, methacrylic acid, and vinyl acetate.
Claim 8
Dependent Claim
34 words
Retroreflective sheeting as defined in claim 5 wherein said cover film comprises a dual-layer composite, each layer being a copolymer (b), the inner layer being a nonionomeric copolymer and the outer, an ionomeric copolymer.
Claim 9
Dependent Claim
82 words
Enclosed-lens retroreflective sheeting comprising substantially a monolayer of lenses anchored in a binder layer, a specularly reflective layer underlying and spaced from the lenses by thermoset transparent material, and a weather-resistant transparent cover film, wherein the improvement comprises: the cover film comprises substantially thermoplastic polymer selected from (a) one or more aliphatic urethanes or (b) one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer.
Claim 10
Dependent Claim
82 words
Enclosed-lens retroreflective sheeting comprising substantially a monolayer of lenses anchored in a binder layer, a specularly reflective layer underlying and spaced from the lenses by thermoset transparent material, and a weather-resistant transparent cover film, wherein the improvement comprises: the cover film comprises substantially thermoplastic polymer selected from (a) one or more aliphatic urethanes or (b) one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer.
Claim 11
Dependent Claim
30 words
Retroreflective sheeting as defined in claim 8 wherein said polymer is a copolymer (b), and said another monomer is at least one of acrylic acid, methacrylic acid, and vinyl acetate.
Claim 12
Dependent Claim
76 words
Method of providing retroreflecting base material with a soft, tough, weather-resistant, transparent cover film comprising the steps of (1) extruding a cover film comprising substantially thermoplastic polymer, which cover film has an elongation of at least 50% and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 2300 N/m width, and (2) contacting the extruded cover film to the retroreflecting base material under heat and pressure to provide retroreflective sheeting.
Claim 13
Dependent Claim
76 words
Method of providing retroreflecting base material with a soft, tough, weather-resistant, transparent cover film comprising the steps of (1) extruding a cover film comprising substantially thermoplastic polymer, which cover film has an elongation of at least 50% and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 2300 N/m width, and (2) contacting the extruded cover film to the retroreflecting base material under heat and pressure to provide retroreflective sheeting.
Claim 14
Dependent Claim
36 words
Method as defined in claim 10 wherein the cover film has an elongation of at least 100%, and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 1000 N/m width.
Claim 15
Dependent Claim
18 words
Method as defined in claim 11 wherein the retroreflecting base material is adhered to a license plate blank.
Claim 16
Dependent Claim
37 words
Method as defined in claim 10 wherein the polymer is one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer.
Claim 17
Dependent Claim
15 words
Method as defined in claim 10 wherein the polymer is one or more aliphatic urethanes.
Claim 18
Dependent Claim
85 words
Method of providing retroreflecting base material with a soft, tough, weather-resistant, transparent cover film comprising the steps of (1) forming a transparent cover film which comprises substantially thermoplastic polymer selected from (a) one or more aliphatic urethanes and (b) one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer and (2) contacting the transparent film to the retroreflecting base material under heat and pressure to provide retroreflective sheeting.
Claim 19
Dependent Claim
85 words
Method of providing retroreflecting base material with a soft, tough, weather-resistant, transparent cover film comprising the steps of (1) forming a transparent cover film which comprises substantially thermoplastic polymer selected from (a) one or more aliphatic urethanes and (b) one or more copolymers of monomers comprising by weight a major proportion of at least one of ethylene and propylene and a minor proportion of another monomer and (2) contacting the transparent film to the retroreflecting base material under heat and pressure to provide retroreflective sheeting.
Claim 20
Dependent Claim
36 words
Method as defined in claim 15 wherein the cover film has an elongation of at least 100%, and a tensile relaxation force from 50% elongation after 5 minutes relaxation of no more than 1000 N/m width.
References Cited (Backward Citations)
US2407680A
Cited
US4511210A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |