Minnesota Mining and Manufacturing Company

Roger R Kult

Terry R Bailey

Howard R Tolliver

Arthur D Dickson

Gregory F Jacobs

James E Lasch

Louis C Belisle

Robert A Haenggi

Michael P Daniels

Thermoplastic based pavement marking sheets are disclosed. The marking sheets employ a conformant composite material including: polyolefin and a nonreinforcing mineral particulate; and/or a thermoplastic upper surface. Preferably, the sheet's thermoplastic upper surface is embedded with reflective elements and/or skid-resistant particles. A solventless process of embedding particles in thermoplastic pavement marking sheets is disclosed. Processes for preparing marking sheets are also disclosed. Conformant pavement marking sheets which may be applied in cooler conditions are also disclosed.

Thermoplastic marking sheet

Process for making conformable thermoplastic marking sheet

Cellular, encapsulated-lens retroreflective sheeting comprising: (1) a base sheet of a monolayer of retroreflective elements partially embedded in a binder layer which typically is white or comprises a whitening agent; (2) a cover sheet disposed in spaced relation from the layer of retroreflective elements; and (3) a network of narrow intersecting bonds or seal legs that extend between the cover sheet and the base sheet and comprise binder material thermoformed at the point of contact between the base sheet and cover sheet so as to adhere the base sheet and the cover sheet together and form a plurality of cells within which retroreflective elements are hermetically sealed; wherein the cover sheet comprises an inner layer and at least a structural layer, the structural layer being adhered to the outside surface of the inner layer. The inner layer of the cover sheet has a higher Vicat Softening Point and/or lower adhesion to the microlenses than at least the structural layer of the cover sheet so that when the cover sheet and base sheet are sealed together and the binder material is thermoformed into contact with the cover sheet to form the seal legs, the binder material is better able to flow around and flood the front surfaces of the retroreflective lenses, thereby hiding same and imparting greater whiteness to the resultant sheeting.

Cellular encapsulated-lens high whiteness retroreflective sheeting with

In encapsulated-lens reflective sheeting of the prior art, a monolayer of glass microspheres is embedded in a binder layer, a specularly reflective layer underlies the microspheres, and a cover film encapsulates the microspheres, within a plurality of hermetically sealed cells. In the invention, a HMW thermoplastic binder film, affords improved structural intregity, greater toughness, and better conformability to irregular surfaces without cracking. The cover film preferably is of the same polymer family as said binder film.

Encapsulated-lens retroreflective sheeting and method of making

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.

Encapsulated-lens retroreflective sheeting having improved cover film

In encapsulated-lens reflective sheeting of the prior art, a monolayer of glass microspheres is embedded in a binder layer, a specularly reflective layer underlies the microspheres, and a cover film encapsulates the microspheres, within a plurality of hermetically sealed cells. In the invention, a HMW thermoplastic binder film, affords improved structural integrity, greater toughness, and better conformability to irregular surfaces without cracking. The cover film preferably is of the same polymer family as said binder film.

Method of making encapsulated-lens retroreflective sheeting

Retroreflective sheeting has a flat, transparent cover film of excellent clarity and weatherability that resists dirt accumulation while also having good flexibility, conformability and stretchability, this desirable combination of properties being achieved when the cover film includes a urethane inner layer and an acrylic outer layer. The acrylic outer layer preferably is a copolymer of 60 to 80 parts of methyl methacrylate and correspondingly 40 to 20 parts by weight of at least one of ethyl acrylate, n-butyl acrylate, and-butyl methacrylate. The urethane inner layer comprises a thermoplastic aliphatic urethane polymer.

Growing community of inventors

Maplewood, MN, United States of America

Roger R Kult