| 摘要 |
<p>1299194 Heat-sensitive stencils RICOH K K 19 Dec 1969 [20 Dec 1968] 61983/69 Heading G2C A heat-sensitive stencil comprises a porous paper support, an adhesive layer and a layer of a thermoplastic resin, the adhesive and resin being capable of being perforated when heated up to 170‹C., and either the adhesive layer or a layer over the thermoplastic layer containing a compound or composition which gives a colour on heating up to the perforation temperature. Specified heat-sensitive compounds or compositions are (i) hexamethylenetetramine nickel or cobalt salts optionally mixed with sulphur and a polyhydric alcohol, (ii) sulphur, benzoin or polyhydric alcohol and a heavy metal salt, (iii) a sacclaride and or acid or alidic salt, (iv) heavy metal salts and an alkaline earth metal sulphide or a tetrathionate, a thiosulphate or a thiourea, (v) silver or mercury oxalate and a polyhydric alcohol or silver oleate or stearate and hydroquinone, spiroindene, protocatechnic acid, (vi) a heavy metal soap and a zinc di-alkyldithiocarbonate and (vii) resorcinol and one nitroso compound. A vinyl chloride vinylidene chloride copolymer is specified as the thermoplastic resin and the adhesive may be polyvinyl acetate, an acrylic resin or a vinylidene chloride/acrylontrile copolymer.</p> |
