| 摘要 |
A light retroreflecting marking composition capable of being applied to a surface as a hot melt at 300-450 DEG F. comprises a colourless non-cloying thermoplastic binder e.g. 15-35% solid at 77 DEG F. and softening to a flowable state at 150-350 DEG F. and hardening solely by cooling, a pigment, e.g. up to 15%, and 20-70% of transparent retroreflecting beads, e.g. glass of diameter 10-1,000 microns, and optionally up to 30% filler: the binder comprises a major amount of a non-cloying thermoplastic resin which is solid at 77 DEG F. and a minor amount of a non-cloying thermoplastic resin of lower softening point than the first resin. The binder may be polystyrene resins, e.g. 65-85% of softening point 100 DEG C. and 15-35% of softening point 5 DEG C., or a non-cloying alkyd resin modified by a non-cloying oil, e.g. a phthalic acid or anhydride glycol alkyds modified with coconut oil mixed with hydrogenated rosin modified with maleican hydride and/or glycerol, and may include a non-cloying plasticizer e.g. a partially epoxidised soyabean oil. The filler may be zinc oxide, asbestine, sand, whiting, calcium carbonate, and may include a material capable of introducing porosity in the composition, e.g. diatomaceous earth. The pigment may be titanium dioxide or cadmium yellow. The beads may be of a plastic of refractive index above 1.3. A 1/32 -/ba1/2 inch thick layer of the composition may be applied to a solid surface, e.g. road, together with a further portion of beads. The composition may be formed into blocks. |
