Abstract: A semi-synthetic rubber latex. The rubber employed in the latex is natural rubber obtained from plant life known to produce polyisoprene. Surprisingly, the semi-synthetic rubber latex is essentially devoid of those proteins that are known to give rise to natural rubber allergenicity or hypersensitivity, and are also essentially devoid of antigens that potentially will give rise to immune responses. Also provided is a method for obtaining the semi-synthetic rubber latex and dipped films thereof that are also substantially free of known natural rubber allergens.

Abstract: A process for reducing the amount of lipids within natural rubber latices comprising the steps of obtaining a natural rubber latex from a guayule bush, the latex having a dry natural rubber content of from about 10 to about 40 percent by weight, adding from about 0.1 to about 25 parts by weight of a surfactant per one hundred parts by weight of dry natural rubber, wherein the surfactant is selected from the group including nonionic, ionic, and amphoteric surfactants, adding from about 1,000 units to about 500,000 units of a lipid reducing enzyme preparation per gram of dry natural rubber, wherein the lipid reducing enzyme preparation is selected from the group including lipases from plant, animal, synthetic and microbial sources, adding a pH buffer to maintain the pH in a range of from about 5 to about 12, mixing the natural rubber latex with the lipid reducing enzyme preparation for a period of between one-half hour to about 24 hours at a temperature of from about 20.degree. C. to about 60.degree. C.

Abstract: Free-flowing particulate compositions matter useful as fuel or soil amendments can be made by impregnating solid particles of guayule bagasse with guayule resins. Processes for making these materials as well as for using them are also disclosed.

Abstract: A stabilizing composition and process for guayule type rubbers which can be directly applied to guayule-type plants or shrubs before processing thereof, or to guayule-type rubber miscella, rubber-resin miscella, etc., contains a volatile low melting point antioxidant which is either liquid or solid and an optional liquid inert carrier which lowers the melting point of the antioxidant. Since antioxidants are generally expensive, recovery thereof as by distillation is aided through the utilization of low boiling point antioxidants.

Abstract: Guayule-type resins are chemically treated with a reactive phenolic resin and a polyether such as an amine terminated polyether. The treated guayule resin has improved physical properties such as higher softening points. The resulting composition is suitable as a rubber additive since it improves various physical properties such as building tack, tear strength, hysteresis loss, and the like.

Abstract: A hydrocarbon insoluble polar fraction is extracted from guayule-like resins by adding a hydrocarbon solvent containing a small amount of water therein to the guayule-like resins and mixing the same. A two-phased solution is formed with the hydrocarbon insoluble polar fraction being located in the water phase. The addition of water to the hydrocarbon increases the yield of the insoluble polar fraction as well as the acid number and the amount of ketoalcohol located therein.

Abstract: There is disclosed the reaction product of an N-(substituted oxymethyl)melamine and a 2-mercaptoarylthiazole and its use as an adhesion promoter to improve rubber to metal wire adhesion.

Abstract: Guayule resin is sulfurized such that it has a high softening point of at least 70.degree. C. The sulfurized guayule resin can be utilized in association with conventional rubbers and the end results in improved properties such as reduced hysteresis loss, increased tensile strength and the like.

Abstract: Guayule-type resins are chemically treated with polyamine. The resulting composition is suitable as a rubber additive since it improves various physical properties of rubber compositions such as green strength, building tack, tear strength, hysteresis loss and the like.

Abstract: There is disclosed the reaction product of an N-(substituted oxymethyl)melamine and a 2-mercaptoarylthiazole and its use as an adhesion promoter to improve rubber to metal wire adhesion.

Abstract: A metal to rubber adhesion promoter comprising the reaction product of a phenol and a substituted melamine, said phenol being ##STR1## wherein R.sub.1 through R.sub.4 are selected from the group consisting of hydrogen, cyclic and acyclic alkyl groups having from 1 to 10 carbon atoms, and a substituted melamine having the formula ##STR2## where R.sub.5 through R.sub.10 may be the same or different and are selected from the group consisting of alkyl groups having from 1 to 5 carbon atoms. The reaction product is a resin and is added to the rubber compound prior to cure. The adhesion promoter is useful in the making of tires having steel belts and in other reinforced rubber articles.