Patent GB-444853-A (GB)
Title: A process for treating natural gums
IPC: C09F1/00
Filed: 1935-04-12
Abstract: The reactivity of a copal gum is increased by heating it to render it plastic and masticating the gum while in this plastic state.  The gum so treated is found to be more readily reactive with such agents as halogens, oxygen, sulphur, amines, and alcohols, not only of the monobasic, polybasic and phenolic types but also partially esterified alcohols such as mono- and di-acetin, mono- and di-olein, mono- and di-glyceridic abietates and mono-and di-glycerides of drying and non-drying oil acids. The step of reaction may, in some cases, be combined with the step of mastication.  In examples: (1) Congo copal is masticated on heated rolls at 300 DEG  F. for 1 hour.  The gum is removed from the rolls, dissolved in pine oil and heated, under reflux, with glycerol until esterification is complete.  (2) Equal parts of ester gum and Benguela copal are milled at 300 DEG  F. for 1 hour, and the mixture is then removed from the rolls and reacted with glycerol.  (3) Equal parts of ester gum and Congo copal are milled at 270 DEG  F. for 1 hour with 10 per cent of pine oil.  The gum solution is removed from the rolls and reacted with 20 per cent of glycerol di-linoleate.  (4) Equal parts of Kauri copal and linseed oil are milled together for 2 hours at 250 DEG  F., and the solution is then neutralized on the rolls by milling in 5 per cent of litharge.ALSO:The solubility and reactivity of a copal gum are increased by heating it to render it plastic and masticating the gum while in this plastic state.  The process may be performed on heated rollers, the gum being preferably first pulverized, temperatures of from 175 DEG  F. to 400 DEG  F. being employed, and the time of mastication varying from about 20 minutes to 2 hours.  Vacuum may be applied to facilitate the removal of volatile products.  The gum so treated is found to be more readily soluble, and more readily reactive with such agents as metallic oxides, hydroxides and salts, halogens, oxygen, sulphur, amines, and alcohols, not only of the monobasic, polybasic and phenolic types but also partially esterified alcohols such as mono- and di-acetin, mono- and di-olein, mono- and di-glyceridic abietates and mono- and di-glycerides of drying and non-drying oil acids.  The steps of solution and/or reaction may, in some cases, be combined with the step of mastication on the heated rolls.  According to examples: (1) Manila copal is milled for 20--30 minutes on rolls at 270 DEG  F., and is then withdrawn from the rolls and dissolved in butanol at 230 DEG  F. to a 50 per cent solution. The acid present in the gum is then neutralized with 1\ba1/2\be per cent of calcium hydrate, and the water of neutralization and the butanol removed by distillation.  (2) Congo copal is masticated on heated rolls at 300 DEG  F. for 1 hour.  The gum is removed from the rolls, dissolved in pine oil and heated, under reflux, with glycerol until esterification is complete.  (3) Congo copal is masticated as in example (2), heated with an equal amount of rosin, and the mixture neutralized with 5 per cent of lime in an open kettle.  (4) Equal parts of ester gum and Benguela copal are milled at 300 DEG  F. for 1 hour, and the mixture is then removed from the rolls and reacted with glycerol.  (5) Equal parts of ester gum and Congo copal are milled at 270 DEG  F., for 1 hour with 10 per cent of pine oil.  The gum solution is removed from the rolls and reacted with 20 per cent of glycerol di-linoleate.  (6) Manila copal is milled for 1 hour at 300 DEG  F., and 2 per cent of lime is then gradually introduced on to the rolls, milling continuing until the lime has disappeared.  (7) Equal parts of Kauri copal and linseed oil are milled together for 2 hours at 250 DEG  F., and the solution is then neutralized on the rolls by milling in 5 per cent of litharge.