Heat-bondable retroreflective sheeting

Claim 2

Retroreflective sheeting of claim 1 which further includes an adhesive layer that forms the back surface of the sheeting, said adhesive layer comprising a thermoplastic heat-activatable adhesive acrylate-based copolymer that comprises an acrylic acid and an acrylate ester.

Claim 3

Retroreflective sheeting of claim 3 in which the acrylate-based copolymer is a copolymer of iso-octylacrylate and acrylic acid.

Claim 4

Retroreflective sheeting of claim 1 in which the specular reflective means comprises a transparent layer of refractive index n1, the faces of said layer being in contact with materials of refractive index n2 and n3, both n2 and n3 being at least 0.1 either higher or lower than n1, at least the material contacting that face most adjacent to the spherical lens elements being transparent, and the transparent layer having an optical thickness corresponding to an odd-numbered multiple of about one-quarter wavelength of light in the wavelength range of about 3, 800 to 10,000 angstroms.

Claim 5

Retroreflective sheeting of claim 5 in which the material of refractive index n2 is the material of the spherical lens elements and the material of refractive index n3 is said binder material.

Claim 6

A laminated product comprising the retroreflective sheeting of claim 1 and a substrate to which the sheeting is adhered.

Claim 7

A laminated product of claim 7 in which the substrate is a photograph.

Claim 8

Retroreflective sheeting comprising a monolayer of minute spherical lens elements; specular reflective means underlying and in optical connection with the back extremities of the spherical lens elements, said specular reflective means comprising a transparent layer of refractive index n1, the faces of said layer being in contact with materials of refractive index n2 and n3, both n2 and n3 being at least 0.1 either higher or lower than n1, at least the material contacting that face of the layer most adjacent to the spherical lens element being transparent, and the transparent layer having an optical thickness corresponding to an odd-numbered multiple of about one-quarter wavelength of light in the wavelength range of about 3,800 to 10,000 angstroms; a layer of binder material adhered to the specular reflective means and supporting the spherical lens elements comprising at least 50 percent of a thermoplastic heat-activatable adhesive copolymer that comprises ethylene, vinyl chloride, and acrylamide; and an adhesive layer that forms the back surface of the sheeting, said adhesive layer comprising a thermoplastic heat-activatable adhesive acrylate-based copolymer that comprises an acrylic acid and an acrylate ester.

Claim 9

Retroreflective sheeting of claim 9 in which the acrylate-based copolymer is a copolymer of iso-octylacrylate and acrylic acid.

Claim 10

Retroreflective sheeting of claim 9 in which the material of refractive index n2 is the material of the spherical lens elements and the material of refractive index n3 is said binder material.

Claim 11

A laminated product comprising the retroreflective sheeting of claim 9 and a substrate to which the sheeting is adhered.

Claim 12

A laminated product of claim 12 in which the substrate is a photograph.

Claim 13

Retroreflective sheeting of claim 9 in which the binder material further comprises a thermoplastic heat-activatable adhesive copolymer that comprises methyl methacrylate, ethyl acrylate, and methacrylic acid.

Claim 14

Retroreflective sheeting of claim 10 in which the binder material further comprises a thermoplastic heat-activatable adhesive copolymer that comprises methyl methacrylate, ethyl acrylate, and methacryLic acid.