High frans-Polybutadiene Is Born Phillips Chemical now offers high-frans polymer in semicommercial quantities With cis-polybutadiene commercially launched, Phillips Chemical is now laying the keel for its polymeric brother, high frans-polybutadiene. The company calls it Trans-4 rubber. And Phillips research heads see the pair as only the beginning of a whole new line of stereospecific polymers and copolymers. Phillips is now producing cte-polybutadiene at the rate of 100 tons per month in its Borger, Tex., plant. It is expanding the plant to a 20,000 tonper-year capacity, scheduled for completion during the last quarter of 1960. Now, high-trans joins Cis-4 at the semicommercial level. Phillips makes high frans-polybutadiene rubber with a solution process that gives a product with about 90% trans content. But the company is keeping secret the operating conditions and the exact catalyst used. Natural Substitute. Synthetic high irans-polybutadiene resembles the natural irans-polyisoprene rubbers, balata and gutta-percha, in many of its properties. Its fortes, claims Phillips, are its high hardness and tensile strength, excellent resilience, and abrasion resistance. Trans-4 rubber has properties of both rubber and plastic. At room temperature it is hard, resin-like, and has a crystalline structure. But since it is thermoplastic, it can be mixed, milled, and extruded in conventional rubberprocessing equipment at elevated temperatures (180° to 280° F . ) . Like most synthetic rubber, it can be vulcanized with conventional cross-linking agents such as sulfur and peroxides. The vulcanized product varies from a hard, inelastic material to one that is soft and rubbery, depending upon cure. Short on Trans. The present tight supply of natural trans-polyisoprene rubbers has encouraged Phillips to spur its Trans-4 rubber development program. Right now, the price of balata and gutta-percha is high, approximately $5.00 per pound. But despite their premium price, these rubbers will probably become more scarce. The U.S. imports only about 1.5 to 2 million pounds of the natural trans
rubbers annually. Most of this goes to golf ball makers, since lower-priced materials like polyethylene have squeezed the natural polymers out of the transoceanic cable-covering market. Golf ball covers need the tough properties of the trans rubbers. With the natural supply dwindling and with golf ball production enjoying an estimated 10% per year growth, makers are looking for synthetic substitutes. More important, this specialty field can bear the "couple of dollars per pound" price at which Trans-4 now sells in semicommercial quantities. Golf ball covers, then, represent the most promising market for Trans-4 at this stage of the game. Future Markets. But there are several other market possibilities for Trans-4. Phillips' tests show that high frans-polybutadiene, compounded with 6 p.h.r. (parts per hundred, rubber) of sulfur, makes a tough, pliable shoe sole with excellent abrasion resistance. Shoe soles represent a relatively large market, about 15 to 20 million pounds per year, by Phillips' estimates. Another possibility: floor
tile. Trans-4 provides an exceptionally long wearing floor tile. Cost, though, is now the big drawback as far as these two markets are concerned. At its present price, Trans-4 could hardly compete with low priced materials such as S BR rubbers, now used in soles, and vinyls, which go into floor tiles. Phillips, however, points out two alternatives. One is that as higher volume production is reached, price of the high trans material will come down—probably not low enough to compete directly with the low cost polymers, but at least to a range where it will attract wider interest. If the spread is not too great, manufacturers may be willing to pay a premium for the improved properties which Trans-4 offers. Secondly, Trans-4 does a good job of improving the characteristics of other rubbers when it is blended with them. Thus, it may find service in upgrading other rubbers. There are other uses for high transpolybutadiene which Phillips is considering. These include wire and cable covering, drive belting, sponges, gaskets, tire beads, and molded parts. But Phillips scientists view transpolybutadiene as important, regardless of its present market potential. They say its development is representative of the control which chemists now have over the structure of rubbers, that it opens the way to a new field of tailor-made, stereospecific polymers.
SYNTHETIC TRANS FOR GOLF BALLS. Natural tram-polyisoprene rubbers, with their high resilience and abrasion resistance, are used in golf ball covers. But the natural supply is dwindling. So Phillips has come up with synthetic trans-polybutadiene to fill the gap
