摘要:
A positive-working printing plate precursor for wet lithographic printing is disclosed which comprises a support having a hydrophilic surface and a coating comprising a first layer closest to the support, said first layer containing an oleophilic phenolic resin soluble in an aqueous alkaline developer, and a second layer containing an amphyphilic polymer, wherein (c) the second layer is capable of preventing the aqueous alkaline developer from penetrating into the first layer to an extent that substantially no dissolution of unexposed coating occurs upon immersion in the aqueous alkaline developer during a time period t2; (d) and wherein said capability of the second layer of preventing the aqueous alkaline developer from penetrating into the first layer is reduced upon exposure to heat or light to an extent that substantially complete dissolution of exposed coating occurs upon immersion in the aqueous alkaline developer during a time period t1; wherein t2>t1 and t2−t1 is at least 10 seconds; and wherein the amphyphilic polymer is a block- or graft-copolymer comprising (i) a poly(alkylene oxide) block and (ii) a block comprising siloxane and/or perfluorohydrocarbon units.
摘要翻译:公开了用于湿平版印刷的正性印刷版前体,其包含具有亲水表面的载体和包含最靠近载体的第一层的涂层,所述第一层含有可溶于碱性显影液的亲油酚醛树脂,和 第二层含有两亲性聚合物,其中(c)第二层能够防止水性碱性显影剂渗透到第一层中,使得在一段时间内浸入含水碱性显影剂中基本上不会溶解未曝光的涂层 t 2 2; (d),并且其中防止水性碱性显影剂渗透到第一层中的第二层的所述能力在暴露于热或光时减少到在浸入含水碱性显影剂中时基本上完全溶解暴露涂层的程度 时间段t 1< 1>; 其中t 2 2和t 2 -T 1 H 1至少为10秒; 并且其中所述无亲性聚合物是包含(i)聚(环氧烷)嵌段和(ii)包含硅氧烷和/或全氟烃单元的嵌段的嵌段或接枝共聚物。
摘要:
A positive-working printing plate precursor for wet lithographic printing is disclosed which comprises a support having a hydrophilic surface and a coating comprising a first layer closest to the support, said first layer containing an oleophilic phenolic resin soluble in an aqueous alkaline developer, and a second layer containing an amphyphilic polymer, wherein(a) the second layer is capable of preventing the aqueous alkaline developer from penetrating into the first layer to an extent that substantially no dissolution of unexposed coating occurs upon immersion in the aqueous alkaline developer during a time period t2;(b) and wherein said capability of the second layer of preventing the aqueous alkaline developer from penetrating into the first layer is reduced upon exposure to heat or light to an extent that substantially complete dissolution of exposed coating occurs upon immersion in the aqueous alkaline developer during a time period t1;wherein t2>t1 and t2−t1 is at least 10 seconds; and wherein the amphyphilic polymer is a block- or graft-copolymer comprising (i) a poly(alkylene oxide) block and (ii) a block comprising siloxane and/or perfluorohydrocarbon units.
摘要:
A lithographic printing method is disclosed which comprising the steps of providing an imaging material which comprises a support and an image-recording layer that is not removable with a single-fluid ink which comprises an ink phase and a polar phase; image-wise exposure of the image-recording layer to heat or light without substantially ablating said image-recording layer, thereby switching the affinity of the image-recording towards ink or an ink-abhesive fluid and thereby creating a printing master comprising a lithographic image which consists of unexposed areas that have affinity for one phase of said ink phase and polar phase and of exposed areas that have affinity for the other phase of said ink phase and polar phase; printing, wherein the single-fluid ink is supplied to the printing master. The exposed image-recording layer, which normally exhibits a poor differentiation of hydrophilicity or oleophilicity between exposed and non-exposed areas, provides high quality printed copies in combination with the single-fluid ink.
摘要:
According to the present invention there is provided a heat-sensitive material for making lithographic plates comprising in the order given on a support an IR-sensitive oleophilic layer and an ablatable cross-linked hydrophilic layer comprising an inorganic pigment and a hardener, characterized in that the ratio of said inorganic pigment over the hardener is comprised between 95/5 and 75/25 by weight.
摘要:
According to the present invention there is provided a heat mode imaging element for providing a lithographic printing plate consisting of a lithographic base with a hydrophilic surface and a top layer that is sensitive to IR-radiation, comprises a polymer soluble in an aqueous alkaline solution, and is unpenetrable for an aqueous alkaline developer, characterized in that said top layer comprises a polysiloxane surfactant.
摘要:
According to the present invention there is provided a heat-sensitive material for making lithographic plates comprising in the order given on a support an IR-sensitive oleophilic layer and a cross-linked hydrophilic layer comprising an inorganic pigment and a hardener, characterized in that the ratio of said inorganic pigment over the hardener is comprised between 75/25 and 25/75 by weight.
摘要:
According to the present invention there is provided a heat mode imaging element for making a lithographic printing plate having on a lithographic base with a hydrophilic surface a first layer including a polymer soluble in an aqueous alkaline solution, and a top layer on the same side of the lithographic base as the first layer that is IR-sensitive and unpenetrable for an aqueous alkaline developer wherein said first layer and said top layer may be one and the same layer; characterized in that the surface of said element upon exposure and treatment with an aqueous alkaline developer is such that a) the contact angle between the unexposed areas of the imaging element and the aqueous alkaline developer changes for at most 6° during the first minute of contact with said developer; b) the contact angle between the exposed areas of the imaging element and the aqueous alkaline developer changes more than 15° during the first minute of contact with said developer; c) the difference in contact angle between on the one side the unexposed areas and on the other side the exposed areas of the imaging element with the aqueous alkaline solution at the onset of the measurement is not higher than 10°.
摘要:
According to the present invention there is provided a heat-sensitive imaging element for making lithographic printing plates. The heat-sensitive imaging element comprises an image-forming layer comprising hydrophobic thermoplastic polymer particles having a specific particle size and polydispersity for obtaining printing plates with an improved sensitivity, excellent developability, high throughput and less scumming.
摘要:
According to the present invention there is provided a heat-sensitive imaging material for making lithographic printing plates which require no processing. The heat-sensitive imaging element comprises on a lithographic base having a hydrophilic surface a metallic or metal oxide layer and on top thereof an oleophobic polymeric layer having a thickness of less than 5 .mu.m and comprising a polymer containing phenolic groups.
摘要:
According to the present invention there is provided a method for making lithographic printing plates including the following stepsa) preparing a heat mode imaging element having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is sensitive to IR-radiation and is unpenetrable for an alkaline developer containing SiO.sub.2 as silicate;b) exposing imagewise said heat mode imaging element to IR-radiation;c) developing said imagewise exposed heat mode imaging element with said alkaline developer so that the exposed areas of the top layer and the underlying areas of the first layer are dissolved and the unexposed areas of the first layer remain undissolved characterized in that said top layer includes an IR-dye.