| 摘要 |
The closed type retroreflecting material is prepared by (1) adjusting to 2,000- 20,000 cps the viscosity of a misture of 10-30 wt.% acrylic copolymer contg. 20-50% solid part, 40-80 wt.% polyurethane resin contg. 20-50% soild part, 0.05-0.5 wt.% benzotriazole UV-stabilizer, 0.01-0.5 wt.% phenolic antioxidizer, and 0.1-1.0 wt.% silicon additive of formula (J) using a mixed solvent, (2) coating polyethylene terephthalate film surface with above mixture in thickness 5 μm-30 μm focusing layer, (5) vacuum depositiong 300-2000A reflecting metal, and (6) releasing the film. Each process of (2), (3) and (4) is followed by drying and hardenign at 100-160 deg.C. In (I), R1 is -HCH3; R2 N and R3 are - CnH2n+1; n is 1-10. In (I), R1 is -HCH3; R2 and R3 are -CnH2n+1; n is 1-10.
|
