| 摘要 |
855,867. Ink. CARIBONUM Ltd. July 16, 1957 [Aug. 14, 1956], No. 24862/56. Drawings to Specification. Class 96. In transfer sheet material for use in manifolding comprising a base web carrying on the surface thereof a substantially colourless coating comprising a continuous phase and a discontinuous phase containing a colourless colourforming substance, the discontinuous phase comprises a plurality of discrete spray-dried particles of pressure-responsive sponge-like material having absorbed therein the colourforming substance, the sponge-like particles normally retaining the colour-forming material but permitting it to be expressed through the continuous phase when the sheet is subjected to writing pressure and thereby to be transferred to a copy sheet in contact with the coated surface of the transfer sheet. The colour-forming material may comprise as described in a solution of one or more substituted mono- or di-leucarnamines dispersed in gelatin or ammonium alginate with or without titanium dioxide or zinc oxide. A suitable receptive coating comprises dextrin, blanc fixe, and phosphotungstic or tannic acid dissolved in dibutyl tartrate and water. The sponge-like particles have a size of 3-6 microns and are surface hardened by treatment during spraying with formaldehyde. Specifications 751,600, 852,131 and U.S.A. Specifications 2,712,507 and 2,730,457 are referred to.
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