Patent US2718979A successfully refreshed from Google Patents.
Patent EP0200521A2 successfully refreshed from Google Patents.
EP0200521A2
Expired / Lapsed
EP
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Delamination-resistant cellular retoreflective sheeting
Assignee: 3M Co
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Filing: 1986-04-28
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Granted: —
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Expires: 2006-04-28
Abstract
Abstract An improved, delamination-resistant, cellular retroreflective sheeting comprising: 1) a base sheet having a layer of retroreflective elements disposed over one of its surfaces, 2) a polymeric cover film disposed in spaced relation from the layer of retroreflective elements, and 3) a network of narrow intersecting bonds extending between said cover film and base sheet to adhere the cover film and base sheet together and form a plurality of cells within which retroreflective elements are hermetically sealed. The cover film, which comprises a continuous polymeric phase and a discontinuous polymeric phase, is biaxially oriented such that the discontinuous polymeric phase is in the form of minute disks distributed substantially uniformly throuout the film. The retoreflective sheeting is resistant to delamination because under the influence of forces that tend to remove the cover film from the base sheet, the cover flim si generally removed only at the edge of the sheeting. e.g., from the front row of cells, but no further, Most of the sheeting remains intact and ready for continued utility.
Inventors
- 👤 David L. C/O Minnesota Mining And Bergeson
- 👤 Lee A. C/O Minnesota Mining And Pavelka
- 👤 Barbara A. C/O Minnesota Mining And Mielke
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 18:37
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/122; G02B5/124; G02B5/126; G02B5/128; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10S428/913; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/2457; Y10T428/24579; Y10T428/24612; Y10T428/25; Y10T428/252
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
111 words
Retroreflective sheeting comprising 1) a base sheet having a layer of retroreflective elements disposed over one of its surfaces; 2) a polymeric cover film disposed in spaced relation from the layer of retroreflective elements; and 3) a network of narrow intersecting bonds extending between said cover film and base sheet to adhere the cover film and base sheet together and form a plurality of cells within which retroreflective elements are hermetically sealed; characterized in that the cover film comprises a continuous polymeric phase and a discontinuous polymeric phase, the film being biaxially oriented such that the discontinuous polymeric phase is in the form of minute disks distributed uniformly throughout the film.
Claim 2
Dependent Claim
111 words
Retroreflective sheeting comprising 1) a base sheet having a layer of retroreflective elements disposed over one of its surfaces; 2) a polymeric cover film disposed in spaced relation from the layer of retroreflective elements; and 3) a network of narrow intersecting bonds extending between said cover film and base sheet to adhere the cover film and base sheet together and form a plurality of cells within which retroreflective elements are hermetically sealed; characterized in that the cover film comprises a continuous polymeric phase and a discontinuous polymeric phase, the film being biaxially oriented such that the discontinuous polymeric phase is in the form of minute disks distributed uniformly throughout the film.
Claim 3
Dependent Claim
47 words
The retroreflective sheeting of claim 1 further characterized in that the cover film comprises a multiphase interpolymer in which the discontinuous phase comprises a first polymeric material and the continuous phase comprises a second more rigid polymeric material polymerized in the presence of the first polymeric material.
Claim 4
Dependent Claim
31 words
The retroreflective sheeting of claim 1 or 2 further characterized in that the discontinuous phase comprises a polymer having a lower glass transition temperature than the polymer of the continuous phase.
Claim 5
Dependent Claim
23 words
The retroreflective sheeting of any one of claims 1, 2, or 3 further characterized in that the discontinuous phase comprises a crosslinked polymer.
Claim 6
Dependent Claim
19 words
The retroreflective sheeting of any one of claims 1-4 further characterized in that the retroreflective elements are transparent microspheres.
Claim 7
Dependent Claim
20 words
The retroreflective sheeting of any one of claims 1-4 further characterized in that the retroreflective elements are cube-cornered retroreflective elements.
Claim 8
Dependent Claim
19 words
The retroreflective sheeting of any one of claims 1-6 further characterized in that the discontinuous phase comprises acrylic-based ingredients.
Claim 9
Dependent Claim
19 words
The retroreflective sheeting of any one of claims 1-7 further characterized in that the continuous phase comprises acrylic-based ingredients.
Claim 10
Dependent Claim
128 words
Retroreflective sheeting comprising 1) a base sheet having a layer of microspheres disposed over one of its surfaces; 2) a cover film disposed in spaced relation from the layer of microspheres; and 3) a network of narrow intersecting bonds extending between said cover film and base sheet to adhere the cover film and base sheet together and form a plurality of cells within which microspheres are hermetically sealed; characterized in that the cover film comprises a multiphase interpolymer comprising a discontinuous crosslinked elastomeric phase and a more rigid thermoplastic continuous phase polymerized in the presence of the elastomeric phase, the elastomeric phase comprising acrylic-based ingredients, and the film being biaxially oriented such that the elastomeric phase is in the form of minute disks distributed uniformly throughout the film.
Claim 11
Dependent Claim
128 words
Retroreflective sheeting comprising 1) a base sheet having a layer of microspheres disposed over one of its surfaces; 2) a cover film disposed in spaced relation from the layer of microspheres; and 3) a network of narrow intersecting bonds extending between said cover film and base sheet to adhere the cover film and base sheet together and form a plurality of cells within which microspheres are hermetically sealed; characterized in that the cover film comprises a multiphase interpolymer comprising a discontinuous crosslinked elastomeric phase and a more rigid thermoplastic continuous phase polymerized in the presence of the elastomeric phase, the elastomeric phase comprising acrylic-based ingredients, and the film being biaxially oriented such that the elastomeric phase is in the form of minute disks distributed uniformly throughout the film.
Claim 12
Dependent Claim
27 words
The retroreflective sheeting of claim 9 further characterized in that the elastomeric phase comprises alkyl or aralkyl acrylate, and the thermoplastic phase comprises alkyl or aralkyl methacrylate.
Claim 13
Dependent Claim
23 words
The retroreflective sheeting of any one of claims 1-10 further characterized in that the disks have average diameters less than about 200 nanometers.
References Cited (Backward Citations)
No citation records indexed.
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