Rosin

Name:
Rosin
Detailed information:

Properties:

Angular, translucent, amber-colored fragments. D 1.08, mp 100–150C, acid number above 150, flash p 370F (187C). Insoluble in water; freely soluble in alcohol, benzene, ether, glacial acetic acid, oils, carbon disulfide, dilute solutions of fixed alkali hydroxides. Hard and friable at room temperature; soft and very sticky when warm. Combustible.

Chief Constituents:

Resin acids of the abietic and pimaric types, having the general formula C19H29COOH and a phenanthrene nucleus.See Turpentine (gum).

Derivation:

From pine trees, chiefly Pinus palustris and Pinus caribaea. (1) Gum rosin is the residue obtained after the distillation of turpentine oil from the oleoresin tapped from living trees. (2) Wood rosin is obtained by extracting pine stumps with naphtha and distilling off the volatile fraction. (3) Tall-oil rosin is a by-product of the fractionation of tall oil.

Grade:

Virgin, yellow dip, hard, NF. Wood rosin grades are B, C, D, E, F, FF, G, H, I, J, K, L, M, N, W-G (window-glass), W-W (water-white). The grading is done by color; B is the darkest and W-W the lightest.

Hazard:

Evolves irritating and suffocating fumes on heating.

Use:

Hot-melt and pressure-sensitive adhesives, mastics and sealants, varnishes, ester gum, soldering compounds, core oils, insulating compounds, soaps, paper sizing, printing inks, polyesters (formed by reaction of the conjugated acids of rosin with acrylic acid, followed by reaction with a glycol).

See Abietic Acid.