摘要：
A transfer sheet material for forming retroreflective graphic images on a substrate, the sheet material comprising a monolayer of transparent microspheres (12); a color layer (22) printed over the microspheres in a first graphic segment of the sheet material in an imagewise pattern, the color layer comprising a colorant in a transparent resin; a reflective layer printed over the microspheres in a second graphic segment of the sheet material in an imagewise pattern, the reflective layer comprising reflective flakes in a transparent binder, wherein the microspheres are partially embedded in at least one of the color layer and the reflective layer, individual microspheres having the reflective flakes arranged in cup-like fashion about their embedded portions; and a bonding layer (28) printed over the color layer and the reflective layer, the bonding layer being sufficiently thick to embed all exposed surfaces of the color layer and the reflective layer and being adapted for use in securing the sheet material to a substrate (30). Also, a method for making such a sheet material. Also, a sheet material having the color layer and the reflective layer combined as a single layer. Also, a sheet material having a graphic segment in which a specularly reflective metal layer is deposited over the microspheres.
权利要求：
CLAIMS:
1. A sheet material for forming retroreflective graphic images on a substrate, the sheet material comprising :
a) a monolayer of transparent microspheres;
b) a color layer printed over the microspheres in a first graphic segment of the sheet material in an imagewise pattern, the color layer comprising a colorant in a transparent resin;
c) a reflective layer printed over the microspheres in a second graphic segment of the sheet material in an imagewise pattern such that overlapping areas of the first and second graphic segments are characterized by the color layer being disposed between the microspheres and the reflective layer, the reflective layer comprising reflective flakes in a transparent binder, wherein the microspheres are partially embedded in at least one of the color layer and the reflective layer, the reflective flakes being small enough relative to the microspheres that individual microspheres have the reflective flakes arranged in cup-like fashion about their embedded portions; and
d) a bonding layer printed over the color layer and the reflective layer, the bonding layer being sufficiently thick to embed exposed surfaces of the color layer and the reflective layer and oeing adapted for use in securing the sheet material to a suostrate.
2. The sheet material of claim 1, further comprising a second color layer printed in the first graphic segment in an imagewise pattern, the second color layer comprising a second colorant in a second transparent resin.
3. The sheet material of claim 1 or 2 bonded to a fabric substrate.
4. The sheet material of any one of claims 1 to 3, wherein the reflective flakes are selected from the group consisting of metal flakes, plastic flakes, metal-plated plastic flakes, and nacreous pigment particles, and wherein the reflective flakes have a thickness in the range of about 0.03 to about 0.8 microns.
5.
The sheet material of any one of claims 1 to 4,
wherein the colorant comprises a transparent pigment or
transparent dye .
6. The sheet material of any one of claims 1 to 5, wherein the color layer and the reflective layer at least partially overlap, the color layer being disposed between the microspheres and the reflective layer to provide a segment of the sheet material which is capable of retroreflecting the color of the color layer when the microspheres in this segment are illuminated with incident light.
7. The sheet material of any one of claims 1 to 6, wherein the bonding layer comprises an extender resin and a heat-activatable, hot-melt adhesive powder fused into the extender resin.
The sheet material of any one of claims 1 to 7,
further comprising a layer of specularly reflective metal adhered to the microspheres in an imagewise pattern to form a third graphic segment.
9. A sheet material for forming retroreflective
graphic images on a substrate, the sheet material comprising :
a) a monolayer of transparent microspheres;
b) a colored reflective layer printed over the microspheres in a first graphic segment of the sheet material in an imagewise pattern, the colored reflective layer comprising a colorant and reflective flakes in a transparent resin, wherein the microspheres are partially embedded in the colored reflective layer, the reflective flakes being small enough relative to the microspheres that individual microspheres have reflective flakes arranged in a cup-like fashion about their embedded portions; and
c) a bonding layer printed over the colored reflective layer, the bonding layer being sufficiently thick to embed all exposed surfaces of the colored reflective layer and being adapted for use in securing the sheet material to a substrate.
10. The sheet material of claim 9 further comprising:
d) a layer of specularly reflective metal adhered to the microspheres in a second graphic segment of the sheet material in an imagewise pattern, the bonding layer being printed over the specularly reflective metal in the second graphic segment, the bonding layer oeing sufficiently thick to embed all exposed surfaces of the specularly reflective metal layer.
11. The sheet material of claim 9 or 10, wherein the reflective flakes comprise aluminum metal flakes.
12. A method for making a transfer sheet material which is adapted to be used in transferring retroreflective graphic images from the sheet material to a substrate, comprising :
a) providing a carrier web;
b) partially embedding a monolayer of transparent microspheres onto the carrier web;
c) printing onto the microspheres in a first graphic segment of the sheet material in a first imagewise pattern with a colorant composition comprising a colorant in a transparent resin and drying the colorant composition to form a color layer;
d) printing onto the microspheres in a second graphic segment of the sheet material a reflective layer composition in a second imagewise pattern such that overlapping areas of the first and second graphic segments are characterized by the color layer being disposed between the microspheres and the reflective layer composition, the reflective layer composition comprising reflective flakes in a transparent binder, and drying the reflective layer composition to form a reflective layer, wherein the microspheres are partially embedded in at least one of the color layer and the reflective layer, the reflective flakes being small enough relative to the microspheres that individual microspheres have the reflective flakes arranged in cup-like fashion about their embedded portions; and
e) thereafter printing onto the first and second graphic segments of the sheet material with a bonding composition to a depth sufficient to embed exposed surfaces of the color layer and the reflective layer and drying the bonding composition to form a bonding layer.
13. The method of claim 12, further comprising
printing onto the microspheres a second colorant composition comprising a second colorant in a second transparent resin
and drying the second colorant composition to form a second color layer.
14. The method of claim 12 or 13, wherein the
reflective flakes are selected from the group consisting of metal flakes, plastic flakes, metal-coated flakes, and nacreous pigment particles.
15.
The method of any one of claims 12 to 14, wherein
the reflective flakes have a thickness in the range of about
0.03 to about 0.8 microns.
16. The method of any one of claims 12 to 15, wherein the microspheres are embedded in the heat-softenable layer to a depth averaging between about 40 and about 50 percent of their diameters.
17. The method of any one of claims 12 to 16, wherein the colorant composition, the reflective layer composition, and the bonding composition are printed by use of a screen printing process.
18. The method of any one of claims 12 to 17, wherein the colorant comprises a transparent pigment.
19. The method of any one of claims 12 to 17, wherein the colorant comprises a transparent dye.
20. Th method of any one of claims 12 to 19, wherein the transparent resin is selected from the group consisting of polyester resins and polyurethane resins.
21. The method of any one of claims 12 to 20, wherein
the transparent binder is selected from the group consisting of polyester binders and polyurethane binders.
22. The method of any one of claims 12 to 21, wherein
the colorant composition and the reflective layer composition are printed in such a manner that they at least partially overlap, the color layer being disposed between the microspheres and the reflective layer to provide a segment of the sheet material which is adapted to retroreflect the color of the color layer when the microspheres in this segment are illuminated with a beam of incident light.
23. The method of any one of claims 12 to 22, wherein the bonding composition is printed to a wet thickness of about 50 to about 100 microns.
24. The method of any one of claims 12 to 23, wherein the bonding layer is formed by printing onto the first and second graphic segments of the sheet material with an extender resin and fusing a heat-activatable, hot-melt adhesive powder into the extender resin.
25. The method of claim 24, wherein the extender resin is selected from the group consisting of polyester extender resins and polyurethane extender resins.
26. The method of claim 24 or 25, wherein the hot-melt adhesive powder comprises a polymeric material selected from the group consisting of polyesters and polyamides.
27. A method for making a transfer sheet material which is adapted to be used in transferring retroreflective graphic images from the sheet material to a substrate, comprising :
providing a carrier web;
partially embedding a monolayer of transparent
microspheres onto the carrier web;
printing onto the microspheres in a first graphic segment of the sheet material in a first imagewise pattern with a first colorant composition comprising a first colorant and metal flakes in a transparent resin and drying the first colorant composition to form a first color layer, wherein the metal flakes form hemispherical reflectors about the embedded portions of the microspheres in the first graphic segment;
printing onto the microspheres in a second graphic segment of the sheet material in a second imagewise pattern with a second colorant composition comprising a second colorant and metal flakes in a transparent resin and drying the second colorant composition to form a second color layer, wherein the metal flakes form hemispherical reflectors about the embedded portions of the microspheres in the second graphic segment; and
printing onto the first and second graphic segments of the sheet material with a bonding composition to a depth sufficient to embed exposed surfaces of the first color layer and second color layer and drying the bonding composition to form a bonding layer.
28. The method of claim 27, wherein the method further
comprises printing onto the microspheres in a third graphic segment of the sheet material in a third imagewise pattern with a reflective layer composition comprising reflective flakes in a transparent resin, and drying the reflective layer composition to form a reflective layer, and further wherein printing onto the first and second graphic segments of the sheet material with a bonding composition further comprises printing onto the third graphic segment of the
sheet material with a bonding composition to a depth sufficient to embed exposed surfaces of the first color layer, second color layer, and reflective layer and drying the bonding composition to form a bonding layer.
SMART & BIGGAR
OTTAWA, CANADA
PATENT AGENTS