"mannans comprising from 1 to 6 hydroxyl groups, for example 2 to 4 hydroxyl groups, per saccharide, substituted with a saturated or unsaturated alkyl chain; polymers or copolymers resulting from the polymerization or copolymerization of an ethylenic monomer, comprising one or more ethylenic, preferably conjugated bonds (or dienes); silicone gums; ethylcellulose, such as the products sold under the" . . . .