Dictionary of National Biography, 1885-1900/Hancock, Thomas (1786-1865)
HANCOCK, THOMAS (1786–1865), founder of the indiarubber trade in England, was second son of James Hancock, a timber merchant and cabinet-maker at Marlborough, Wiltshire, where he was bcrn 8 May 1786. Walter Hancock [q. v.] was a younger brother. He was educated at a private school in his native town, and after spending his 'earlier days in mechanical pursuits,' as he states in his 'Personal Narrative,' he came to London. About 1819 his attention was directed to the uses of indiarubber. His first patent, which bears date 29 April 1820, related to the application of indiarubber springs to various articles of wearing apparel. Observing that two freshly-cut surfaces of indiarubber readily adhered by simple pressure, he was led to the invention of the 'masticator,' as it was afterwards called, by the aid of which pieces of indiarubber were worked up into a plastic and homogeneous mass. This machine consists of a roller set with sharp knives or teeth, revolving in a hollow cylinder of slightly larger diameter, into which the material to be operated upon is introduced. The knives, or teeth, tear the indiarubber in every direction, thus producing a constant succession of freshly cut surfaces which adhere together by the effect of the heat evolved during the operation, and by the pressure against the cylinder. By aid of the masticator a substance was obtained capable of being pressed into blocks, or rolled into sheets. With the invention of this process, which was perfected about 1821, the india-rubber trade commenced. Hancock took premises in the Goswell Road (where his successors still carry on business), and commenced manufacturing indiarubber. The masticating process was never patented, but remained a secret in the factory until about 1832, when it was divulged by a workman. Experiments showed that masticated india-rubber was much more easily acted upon by solvents than ordinary rubber, and this discovery brought him into communication with Macintosh, the well-known manufacturer of waterproof garments, who carried on business at Manchester. Eventually Hancock became a partner in the firm of Charles Macintosh & Co., though he still carried on his own business in London.
Indiarubber articles still possessed serious defects due to the material itself; they became sticky, and at low temperatures lost their elasticity. In 1842 specimens of 'cured' indiarubber, prepared in America by Charles Goodyear according to a secret process, were exhibited in this country. Hancock investigated the matter, and discovered that when indiarubber was exposed to the action of sulphur at a certain temperature a change took place. He thus obtained 'vulcanised' india-rubber, which is capable of resisting extremes of heat and cold, and is very durable. This discovery was patented 21 Nov. 1843. Although Hancock was not the inventor of vulcanising in the strictest sense of the word, he first showed that sulphur alone is sufficient to effect the change, whereas Goodyear employed other substances in addition. Hancock also discovered that if the vulcanising process is continued, and a higher temperature employed, a horny substance, now called vulcanite or ebonite, is produced. This is said to have been the result of an accident, a number of samples having been left in the oven and forgotten. The manufacture of 'hard' indiarubber is also included in Hancock's patent.
Hancock took out sixteen patents in all relating to indiarubber between 1820 and 1847. He displayed remarkable ingenuity in suggesting uses for what was practically a new material, and the specifications of his patents cover the entire field of indiarubber manufactures, though many of his ideas were not carried out at the time. His brothers Charles, John, Walter, and William were also associated with him, and were concerned in patents for developing various branches of the trade. Hancock died 26 March 1865, at Stoke Newington, where he had lived for fifty years.
He published at London in 1857 'Personal Narrative of the Origin and Progress of the Caoutchouc or Indiarubber Manufacture in England.'
[Hancock's Personal Narrative, 1857.]