An adhesive material is made by chemically bonding a major proportion of a vulcanizable rubber with a minor proportion of a heat reactive "A" stage resin obtained by reacting a para-substituted hydroxy phenol with an aldehyde or ketone, the bonding being effected by treatment at such an elevated temperature for such time that the mass assumes a swelling volume, as defined in the Specification between 20 and 36, the reaction then being terminated so that the product is stabilized in a soft flexible and substantially non-stringy state. The rubber may be natural rubber, polyisoprene polychloroprene, or a copolymer of isobutylene such as butyl rubber, or a copolymer of butadiene with styrene, methacrylate, acrylate or acrylonitrile. The phenol is preferably substituted by an ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, phenyl, menthyl or ethyl benzene group. Specified resins are those known under the Registered Trade Marks "Durez" 202 and "Bakelite" BR 14634; and also "Amberol" St. 137. The nature of the product may be modified by the addition of fillers such as zinc oxide, aluminium oxide, titanium dioxide and calcium carbonate; by tackifying resins such as rosin, dehydrated rosin, hydrogenated rosin, their glycol, polyglycol and glycerol esters, their penta-erithritol esters and maleic alkyd modifications; polypinenes, coumarone-indene resins, hydrogenated coumarone indene resins and polyisobutylene; and also accelerators and modifiers such as metal compound acids, strong oxidizing agents, copper oleate and other copper compounds, lime and other calcium compounds, lead acetate, lead oxide, lead dioxide, and other lead compounds, magnesium oxide and other magnesium derivatives, zinc, zinc oxide and other zinc derivatives, lauryl peroxide, phosphoric pentoxide, lecithin or triethylamine; plasticizers such as petroleum oils, soft waxes and high boiling esters such as methyl abietate; and solvents such as naphtha, xylene, benzene or toluene. In example I, which is typical of many, 100 parts of GR-S and 100 parts of zinc oxide are mixed on a Banbury mixer and then 75 parts of the glyceride of hydrogenated rosin added and then the mixture steam heated on reaching 270 DEG F., 10 parts of para tertiary amyl phenol formaldehyde condensation product are added and heating continued until the required swelling volume is reached. 33 parts of a petroleum hydrocarbon oil and 2 parts of an antioxidant such as an alkylated polyhydroxy phenol are added and then the mixture thinned with an organic solvent.ALSO:An adhesive material is made by chemically bonding a major proportion of a vulcanizable rubber with a minor proportion of a heat reactive para-substituted hydroxy phenyl carbinol, the bonding being effected by treatment at such an elevated temperature for such time that the mass assumes a swelling volume, as defined in the Specification between 20 and 36, the reaction then being terminated so that the product is stabilized in a soft flexible and substantially non-stringy state. The rubber may be natural rubber, polyisoprene, polychloroprene, or a copolymer of isobutylene such as butyl rubber, or a copolymer of butadiene with styrene, methacrylate, acrylate or acrylonitrile. The phenol is preferably substituted by an ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, phenyl, menthyl or ethyl benzene group, and is then treated preferably with formaldehyde to produce an "A" stage resin. Specified resins are those known under the Registered Trade Marks "Durez" 202 and "Bakelite" BR 14634; and also "Amberol" St. 137. The nature of the product may be modified by the addition of fillers such as zinc oxide, aluminium oxide, titanium dioxide and calcium carbonate; by tackifying resins such as rosin, dehydrated rosin, hydrogenated rosin, their glycol, polyglycol and glycerol esters, their penta-erithritol esters and maleic alkyd modifications; polypinenes, coumarone - indene resins, hydrogenated coumarone indene resins and polyisobutylene; and also accelerators and modifiers such as metal compounds, acids, strong oxidizing agents, copper oleate and other copper compounds, lime and other calcium compounds, lead acetate, lead oxide, lead dioxide, and other lead compounds, magnesium oxide and other magnesium derivatives, zinc, zinc oxide and other zinc derivatives, lauryl peroxide, phosphoric pentoxide, lecithin or triethylamine; plasticizers such as petroleum oils, soft waxes and high boiling esters such as methyl abietate; and solvents such as naphtha, xylene, benzene or toluene. In example I, which is typical of many, 100 parts of GR-S and 100 parts of zinc oxide are mixed on a Banbury mixer and then 75 parts of the glyceride of hydrogenated rosin added and then the mixture steam heated, on reaching 270 DEG F., 10 parts of para tertiary amyl phenol formaldehyde condensation product are added and heating continued until the required swelling volume is reached. 33 parts of a petroleum hydrocarbon oil and 2 parts of an antioxidant such as an alkylated polyhydroxy phenol are added and then the mixture thinned with an organic solvent.