Patent US4896943A successfully refreshed from Google Patents.
US4896943A
Expired / Lapsed
US
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Encapsulated-lens retroreflective sheeting having improved cover film
Assignee: 3M Co
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Filing: 1987-05-13
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Granted: 1990-01-30
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Expires: 2007-05-13
Abstract
Abstract An encapsulated-lens retroreflective sheeting comprising a monolayer of lenses partially embedded in a binder layer, a specularly reflective layer underlying the lenses, and a cover film sealed to the binder layer along a network of interconnecting lines forming hermetically sealed cells within which the lenses are encapsulated and have an air interface, wherein the cover film comprises polyethylene, or polypropylene, or a copolymer comprising a major portion by weight of at least one of ethylene or propylene and a minor portion by weight of a comonomer. Such a cover film affords high flexibility, improved impact resistance, resistance to moisture absorption, and greater toughness to the retroreflective sheeting. In some embodiments the cover film is multi-layer.
Inventors
- 👤 Howard R. Tolliver
- 👤 Roger R. Kult
- 👤 Terry R. Bailey
- 👤 Arthur D. Dickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:38
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128; B; B29; B29D; B29D11/00; B29D11/00605; B29D11/00615; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/252
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
94 words
An encapsulated-lens retroreflective sheeting comprising a monolayer of lenses partially embedded in a binder layer, a specularly reflective layer underlying the lenses, and a cover film sealed to the binder layer along a network of interconnecting lines forming hermetically sealed cells within which the lenses are encapsulated and have an air interface, wherein: the cover film comprises polyethylene, or polypropylene; or a copolymer comprising a major portion by weight of at least one of ethylene or propylene and a minor portion by weight of at least one comonomer; blends of polyethylene, polypropylene, or copolymers.
Claim 2
Dependent Claim
94 words
An encapsulated-lens retroreflective sheeting comprising a monolayer of lenses partially embedded in a binder layer, a specularly reflective layer underlying the lenses, and a cover film sealed to the binder layer along a network of interconnecting lines forming hermetically sealed cells within which the lenses are encapsulated and have an air interface, wherein: the cover film comprises polyethylene, or polypropylene; or a copolymer comprising a major portion by weight of at least one of ethylene or propylene and a minor portion by weight of at least one comonomer; blends of polyethylene, polypropylene, or copolymers.
Claim 3
Dependent Claim
20 words
The sheeting of claim 1 wherein one of said comonomers is acrylic acid, methacrylic acid, vinyl acetate, or ethyl acrylate.
Claim 4
Dependent Claim
37 words
The sheeting of claim 1 wherein said cover film comprises a copolymer comprising a major portion by weight of at least one of ethylene or propylene, and a minor portion by weight of at least one comonomer.
Claim 5
Dependent Claim
15 words
The sheeting of claim 1 wherein said cover film is at least 1 mil thick.
Claim 6
Dependent Claim
18 words
The sheeting of claim 4 wherein said cover film is between about 1 mil and 10 mils thick.
Claim 7
Dependent Claim
18 words
The sheeting of claim 1 wherein said cover film is between about 2 mils and 6 mils thick.
Claim 8
Dependent Claim
22 words
The sheeting of claim 1 wherein the inner surface of said cover film is primed to improve compatibility with said binder layer.
Claim 9
Dependent Claim
13 words
The sheeting of claim 7 wherein said prime comprises a polymeric priming layer.
Claim 10
Dependent Claim
20 words
The sheeting of claim 8 wherein said polymeric priming layer is of the same polymer family as said binder layer.
Claim 11
Dependent Claim
12 words
The sheeting of claim 8 wherein said polymeric priming layer comprises aziridine.
Claim 12
Dependent Claim
11 words
The sheeting of claim 1 wherein said lenses are glass microspheres.
Claim 13
Dependent Claim
11 words
The sheeting of claim 1 wherein said cover film is multi-layer.
Claim 14
Dependent Claim
51 words
The sheeting of claim 1 wherein said cover film is dual-layer, comprising: an inner layer which comprises polyethylene, polypropylene, or a copolymer comprising a major portion by weight of at least one of ethylene or propylene and a minor portion by weight of at least one comonomer; and an outer layer.
Claim 15
Dependent Claim
37 words
The sheeting of claim 13 wherein said inner layer comprises a copolymer comprising a major portion by weight of at least one of ethylene or propylene, and a minor portion by weight of at least one comonomer.
Claim 16
Dependent Claim
37 words
The sheeting of claim 13 wherein said outer layer comprises a copolymer comprising a major portion by weight of at least one of ethylene or propylene, and a minor portion by weight of at least one comonomer.
Claim 17
Dependent Claim
11 words
The sheeting of claim 1 wherein said binder layer is white.
Claim 18
Dependent Claim
13 words
The sheeting of claim 1 wherein said binder layer contains a whitening agent.
Claim 19
Dependent Claim
12 words
The sheeting of claim 17 wherein said whitening agent is a pigment.
Claim 20
Dependent Claim
19 words
The sheeting of claim 1 wherein said binder layer is of a different polymer family from said cover film.
Claim 21
Dependent Claim
13 words
The sheeting of claim 1 wherein said cover film comprises a weathering stabilizer.
Claim 22
Dependent Claim
27 words
The sheeting of claim 20 wherein said weathering stabilizer comprises at least one of the following: antioxidant, energy quencher, hindered amine light stabilizer or ultraviolet radiation absorber.
Claim 23
Dependent Claim
12 words
The sheeting of claim 1 wherein said cover film comprises a dye.
Claim 24
Dependent Claim
17 words
The sheeting of claim 1 wherein said cover film has a transmittance of at least 75 percent.
Claim 25
Dependent Claim
17 words
The sheeting of claim 1 wherein said cover film has a transmittance of at least 85 percent.
Claim 26
Dependent Claim
18 words
The sheeting of claim 1 wherein said cover film comprises a conditioning layer on the outside surface thereof.
References Cited (Backward Citations)
US2407680A
Cited
US3190178A
Cited
US3935359A
Cited
US3874914A
Cited
US4025159A
Cited
US4288493A
Cited
US4618518A
Cited
US4637950A
Cited
US4663213A
Cited
US4664966A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |