16.1.History and Classifications 331 Latex is only workable when freshly tapped from the rubber tree.Thus,Europeans struggled considerably to find solvents for caoutchouc to make it spreadable after it arrived in Europe in its "dried"(actually,coagulated,i.e.,solid)state.Efforts utilizing ether,turpentine,or naphtha (a waste product from coal-gas plants)were only partially successful since the waterproofed items,produced from rubber,remained sticky particularly when warm,and turned to dust in hot summers.Moreover,these rub- ber items were odorous,perishable,and became brittle and even cracked upon the slightest use during extremely cold winters. Nevertheless,a large number of products were manufactured in the early 1800s,such as air mattresses,portable bath tubs,wa- terproof mailbags,boots,and,notably,"mackintoshes"(named after their Scottish inventor).The latter material consisted of a mixture of naphtha and rubber which was sandwiched between double layers of cloth.This procedure alleviated the exposure of a tacky surface which was so annoying in earlier products. A different(nonchemical)approach was applied in the 1820s by Thomas Hancock in England.He built a machine that rapidly cuts rubber into small pieces which generated heat and thus fa- cilitated the fusing of rubber scraps into blocks.This process is called masticationo and is still used in the rubber industry. Riding on the rubber boom of the 1830s was Charles Goodyear of Boston(USA)who,in the cold winter of 1839,after considerable experimentation,accidentally dropped a piece of rubber coated with sulfur and lead?onto a hot stove.Both white lead (a common pig- ment)and sulfur were used before by others in this context,but it was Goodyear who recognized the transformation(curing)process that occurred during heating.The new substance did not melt(as untreated rubber would do);it was durable and retained its plia- bility and elasticity when cold.This technique of vulcanization is still used today with very little modification.However,Goodyear's discovery was made at a time when rubber had a bad reputation because many rubber products had failed in extreme weather.As a consequence,potential investors were reluctant to risk money for the support of additional experimentation.Further,Goodyear was imprisoned for debt more than once,which required him to sell even his children's school books at one point.Nevertheless,in 1842, Goodyear received a U.S.patent which became probably the most litigated one in history (about 150 suits were filed in the first 12 years).Goodyear received a gold medal for excellence at the inter- national exhibitions in London and Paris in the 1850s,at which he displayed his entire vision about the future of rubber products,in- 6Mastikhan (Greek)=to grind the teeth. 7Other sources say zinc.Latex is only workable when freshly tapped from the rubber tree. Thus, Europeans struggled considerably to find solvents for caoutchouc to make it spreadable after it arrived in Europe in its “dried” (actually, coagulated, i.e., solid) state. Efforts utilizing ether, turpentine, or naphtha (a waste product from coal-gas plants) were only partially successful since the waterproofed items, produced from rubber, remained sticky particularly when warm, and turned to dust in hot summers. Moreover, these rub￾ber items were odorous, perishable, and became brittle and even cracked upon the slightest use during extremely cold winters. Nevertheless, a large number of products were manufactured in the early 1800s, such as air mattresses, portable bath tubs, wa￾terproof mailbags, boots, and, notably, “mackintoshes” (named after their Scottish inventor). The latter material consisted of a mixture of naphtha and rubber which was sandwiched between double layers of cloth. This procedure alleviated the exposure of a tacky surface which was so annoying in earlier products. A different (nonchemical) approach was applied in the 1820s by Thomas Hancock in England. He built a machine that rapidly cuts rubber into small pieces which generated heat and thus fa￾cilitated the fusing of rubber scraps into blocks. This process is called mastication6 and is still used in the rubber industry. Riding on the rubber boom of the 1830s was Charles Goodyear of Boston (USA) who, in the cold winter of 1839, after considerable experimentation, accidentally dropped a piece of rubber coated with sulfur and lead7 onto a hot stove. Both white lead (a common pig￾ment) and sulfur were used before by others in this context, but it was Goodyear who recognized the transformation (curing) process that occurred during heating. The new substance did not melt (as untreated rubber would do); it was durable and retained its plia￾bility and elasticity when cold. This technique of vulcanization is still used today with very little modification. However, Goodyear’s discovery was made at a time when rubber had a bad reputation because many rubber products had failed in extreme weather. As a consequence, potential investors were reluctant to risk money for the support of additional experimentation. Further, Goodyear was imprisoned for debt more than once, which required him to sell even his children’s school books at one point. Nevertheless, in 1842, Goodyear received a U.S. patent which became probably the most litigated one in history (about 150 suits were filed in the first 12 years). Goodyear received a gold medal for excellence at the inter￾national exhibitions in London and Paris in the 1850s, at which he displayed his entire vision about the future of rubber products, in- 16.1 • History and Classifications 331 6Mastikhan (Greek)
to grind the teeth. 7Other sources say zinc