| 摘要 |
A pastel paint composition comprises a white pigment or pigments having an index of refraction of at least 1.8, preferably at least 2.5, less than 50% by weight with respect to the white pigment of a daylight fluorescent pigment which is in sufficient quantity to impart a pastel colour to the white pigment, but insufficient to impart a fluorescent appearance thereto, and a binder for the pigments. The fluorescent pigment may be present in an amount up to 45% by weight of the total solids in the paint and in specific examples given about 5% thereof. Suitable white pigments are rutile- or anatase-derived titanium dioxide, possibly with calcium sulphate or aluminium silicate extender; zinc oxide; antimony oxide; and lithopone (zinc white); also mentioned as providing non-suitable paints are calcium carbonate; magnesium silicate; and silica. Suitable fluorescent pigments are rhodamines or coumarins dispersed in a resinous carrier such as a co-condensed product including formaldehyde, an aromatic sulphonamide (toluene sulphonamide) and an aminotriazine (benzoguanamine). A suitable binder is a combination of an acrylic ester resin and an acrylic modified alkyd resin. Polyethylene or polystyrene may also be used as a binder. A wetting agent may be added to the binder. The fluorescent pigment has a particle size of 5-20 microns, although the use of particles having a size of 1-5 microns is mentioned. The paint may further include the usual additives, i.e. thinners, driers, anti-skinning agents &c. |
