An antislip composition for application to the handle of sporting apparatus such as tennis rackets and which does not transfer readily to the hand and remains effective even with a high degree of sweating, consists essentially of 10 to 50% by weight of rosin, 10 to 40% by weight of microcrystalline wax, 10 to 50% by weight dammar resin or a synthetic resin with similar properties and the balance to 100% by weight paraffin.

Alkali-soluble hot melt adhesive compositions are provided which contain (a) about 10-40 weight % of an alkenyl succinic anhydride, (b) a carboxyl group containing ethylene copolymer, and (c) about 10-50 weight % of rosin.

Formic acid is disclosed as a catalyst for polymerizing rosin. The discovery is the basis of a method for polymerizing rosin by heating the rosin in the presence of a catalytic proportion of formic acid. The catalyst is easily separated from the polymerized rosin for reuse.

A method and apparatus are disclosed for delivering particulate material while minimizing the release of dust. The apparatus comprises a vertical conduit, and movable flap adapted to close the lower end of the conduit and a counterwieght or linear actuator for moving the flap to close the conduit whenever the quantity of material within the conduit drops to be predetermined level. The device operates so that a column of solid particulate material is maintained in the lower end of the tube at all times to prevent escape of dust.

An improved, stable rosin ester tackifier consisting essentially of an adduct of rosin and a polyhydric alcohol selected from the group consisting of trimethylolpropane, trimethylolethane, and mixtures thereof, and hot melt adhesive compositions consisting essentially of said tackifier and a polymer component, said compositions containing a mixture of antioxidants containing a higher alkyl diester of thiopropionic acid, a hindered phenolic compound and a phenol sulfide compound, preferably an alkyl phenol disulfide oligomer.