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: A repaired elastomer article having a cut or crack entirely therethrough. An interior cavity is located in the vicinity of the cut or crack and has a filler therein. A treating agent is located about the cut portion on the inner surface of the article and an amine curable polymer or prepolymer resides over said treating agent. A cured elastomeric patch resides over said amine curable polymer or prepolymer. Since the amine curable polymer or prepolymer cures at ambient temperatures, the repair of the elastomer article can occur in situ. The invention is especially useful in the repair of tires.

Abstract: Urethane compositions generally free of phase separation patterns and flow lines are produced. One method includes the utilization of a nucleating compound which is generally added to a urethane prepolymer before any chain extension thereof. Examples of nucleating agents include urethanes, ureas and allophanates such as carboxylic acids, organic acid and anhydrides, amides, imides and the like. Another method includes adding a very small initial incremental amount of a curing agent to the prepolymer with an insoluble product being produced thereby and subsequently adding the remainder of the curing agent.

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: A process and product thereof for densifying guayule shrubs by compression and forming a densified pellet. The densified pellet substantially maintains its molecular weight during storage over a period of weeks without the aid of any inert gas blanket or the like.

Abstract: Rubber curing agents such as quinoids are solution compounded to achieve a uniform or homogeneous distribution thereof in a rubber composition. The curing agents are initially solubilized in an organic polar solvent and then mixed with the rubber masterbatch solution. The solvent is then removed. A uniform fine distribution of the curing agent results in improved physical properties. The present invention is particularly suitable as a sealant composition for tires.

Abstract: A process for drying lactams to extremely low water contents is provided which comprises mixing the lactam with hydrocarbon distilling from the mixture a water/hydrocarbon vapor and or condensate, contacting said vapor or condensate with a drying agent to remove water and returning the dried distillate to the mixture to permit recycling process is capable of providing anionic polymerization grade lactam with a water content of less than about 50 ppm.

Abstract: A process and urethane composition for making urethane prepolymers from a polyisocyanate and blends of two or more urethane intermediates. The prepolymers so produced when cured have improved physical properties such as high low strain modulus and tensile strength relative to cured polyurethanes prepared from a mixture of prepolymers prepared by reacting a polyisocyanate with the component intermediates and subsequently blending the prepolymers.

Abstract: Rubber compositions and metal-reinforced rubber ply members have improved metal adhesion and metal adhesion retention. The improvement comprises admixing from about 0.5 to about 10.0 parts per hundred rubber (phr) of bis(2-mercaptobenzothiazato) nickel with a vulcanizable rubber composition prior to combining the metal and rubber and then curing. A method for improving the metal adhesion and metal adhesion retention between a vulcanizable rubber and metal member includes the step of dispersing from about 0.5 to about 10.0 phr of nickel in a vulcanizable rubber composition prior to curing.

Abstract: A method for improving metal adhesion and metal adhesion properties between a vulcanizable rubber composition and brass or zinc or brass-plated or zinc-plated metallic reinforcing elements includes dispersing from about 0.5 to about 12.5 parts by weight of an organic salt of nickel or cobalt per 100 parts of rubber component in a sulfur vulcanizable rubber composition and dispersing from about 0.5 to 15 parts by weight of a thermosetting two-step phenolic resin per 100 parts of the rubber component in the same rubber composition prior to curing.

Abstract: A method for separating guayule bagasse from a guayule-solvent mixture utilizing a monophase solvent. Upon the addition of water, a two-phase system is formed wherein the bagasse is located just below the monophase solvent-water interface.

Abstract: Including certain carboxy-terminated butadiene-acrylonitrile copolymers in natural rubber formulations increases their tear strength, and hardness properties.

Abstract: This invention is directed toward a method for improving the green strength properties of vulcanizable rubber compositions comprising the step of mixing a halogenated polymer with the vulcanizable rubber composition prior to curing in an amount ranging from about 5 to 25 weight percent of the rubber in the composition.

Abstract: Urethane compositions are prepared which contain preformed adducts. The preformed adducts are prepared by reacting a polyisocyanate with various polyols or amine analogs thereof whereby a product insoluble in the urethane prepolymer is produced. An intermediate polyol is added to produce a prepolymer. The cured urethane compositions have high low-strain moduli.

Abstract: Urethane elastomers are produced by initially adding at least one incremental amount of a curing agent to a urethane prepolymer, having free polyisocyanate therein. Generally, free polyisocyanate-curing agent adducts are precipitated. Subsequently, the remaining amount of curing agent is added. Chain extension, accordingly, is favored which produces hard segment domains more evenly distributed in the polymer chain and imparts improved physical properties such as hardness, tear strength and high-low strain modulus.

Abstract: Filled rubber vulcanizates containing aromatic furazan oxides exhibit many improved properties such as increased filler-rubber interaction and decreased hysteresis. Useful furazan oxides have both carbons of the furazan ring as part of a fused aromatic ring. Typical examples are benzofurazan oxide and its methyl and methoxy analogs. Tires made from the inventive vulcanizates show lower running temperatures and improved rolling resistance. The desirable effects of the aromatic furazan oxides may be improved by mixing the rubber, filler and furazan oxide in a conventional mechanical compounding device at specific temperatures and time periods such as about 200.degree.-400.degree. F. for 2-20 minutes.

Abstract: Combinations of para-phenylene diamines and para di(nitroso) arenes act synergistically in guayule rubber-based compositions to protect them against oxidative degradation. A typically useful diamine is N-(1,3-dimethylbutyl)-N'-phenyl-phenyl-p-phenylene diamine and a useful arene is para-di(nitroso)benzene. Vulcanizable compositions, as well as articles made therefrom, are within the scope of the invention.

Abstract: Elastomers such as guayule rubber is stabilized by the addition of an alkyl, cycloalkyl or alkyl substituted cycloalkyl phenyl-phenylenediamine compound with an alkyl, cycloalkyl or alkyl substituted cycloalkyl phosphite compound which, in combination, yield an unexpectant and synergistic result.

Abstract: The process described herein comprises the crosslinking by radiation of a miscible mixture of two or more homopolymers such as A and B, etc., to give a block copolymer having one or more blocks of A and one or more blocks of B. This process has the advantage of effecting crosslinking between blocks at such a rapid rate that substantial crosslinking is effected before phase separation occurs. Moreover, the process may be modified by agents which promote crosslinking and also by compatibilizing agents to give improved miscibility of the A and B homopolymers. Other modifications of the process effect improvements either by centrifugal separation of gelled high molecular weight products or by breaking down the molecular weights of such gelled portion either by mechanical shear or by ultrasonic treatment. The product of this invention has a variety of uses such as in adhesive and coating compositions, molding compositions, compatibilizing agents, etc.

Abstract: Carbon black products useful in rubber compositions, and rubber compositions (uncured or cured) containing said carbon black products are described. The carbon black products of the invention comprise carbon black having a surface area of at least 20 m.sup.2 /g. and up to about 10% by weight, based on the weight of the carbon black of at least one aromatic furazan oxide. Useful furazan oxides have both carbons of the furazan ring as part of a fused aromatic ring, and particular examples include benzofurazan oxide, and its methyl and methoxy analogs. Improvements in the processability of uncured rubber compositions containing the carbon black products of the invention have been observed.Filled rubber vulcanizates containing the carbon black products of the invention exhibit many improved properties such as increased filler-rubber interaction and decreased hysteresis.