| 摘要 |
A true processless lithographic printing precursor comprising a substrate, a layer of imaginable element on the substrate. The imaginable element comprising: (1) a substance capable of converting radiation into heat; (2) hydrophobic polymer particles and (3) hydrophilic polymer particles. The imaginable element can not be removed by water or fountain used for press when coated and dried, and becomes hydrophobic under the action of heat. The converter substance may be selected to have an absorption spectrum that is optimized to absorb at the wavelength of imaging radiation. The hydrophilic polymer particles are made by polymerization of at least one hydrophilic monomer and the hydrophobic polymer particles are made by polymerization of at least one hydrophobic monomer. Hydrophilic particles comprise major hydrophilic polymer and reject the ink or oil, and hydrophobic particles comprise major hydrophobic polymer and accept the ink or oil. The processless lithographic printing precursor so created may be imaged using absorbed radiation that is imagewise converted to heat, resulting in areas of hydrophobic property, while unimaged areas retain their hydrophilic property. This allows the latent image so formed to be employed in creating a negative-working lithographic printing master. The negative-working lithographic printing master so created is irreversible, does not require a substrate of controlled hydrophilicity and provides great toughness in the exposed areas.
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