Abstract:
Images can be provided using a method comprising thermally imaging a negative-working imageable element to provide an imaged element with exposed regions and non-exposed regions, the exposed regions consisting essentially of coalesced core-shell particles, and developing the imaged element on-press to remove only the non-exposed regions using a lithographic printing ink, fountain solution, or both. The imageable element comprises a single thermally-sensitive imageable layer consisting essentially of an infrared radiation absorbing compound and core-shell particles that coalesce upon thermal imaging. The core of the core-shell particles is composed of a hydrophobic thermoplastic polymer, the shell of the core-shell particles is composed of a hydrophilic polymer that is covalently bonded to the core hydrophobic thermoplastic polymer, and the thermally-sensitive imageable layer comprises less than 10 weight % of free polymer.
Abstract:
A method is described for producing an imaged lithographic printing plate, wherein the developer comprises a hydrophilic polymer comprising (m1) structural units derived from at least one compound comprising both a polyalkylene oxide chain and a free radical polymerizable group, and (m2) structural units derived from at least one compound copolymerizable with the free radical polymerizable group of (i) and comprising at least one functional group with pKs
Abstract:
Imageable elements useful as lithographic printing members are disclosed. The elements contain a substrate, an underlayer, and a top layer. The underlayer contains a combination of polymeric materials that provides resistance both to fountain solution and to aggressive washes, such as a UV wash. The underlayer can be used in either thermally imageable or photochemically imageable elements.
Abstract:
The invention relates to coating solutions, processes for the preparation of a printing plate using these coating solutions as well as printing plates prepared in this manner; in particular, the invention relates to printing plates the photosensitive layer of which contains homogeneously distributed polymer particles.
Abstract:
A lithographic printing plate precursor comprises an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye comprising an infrared radiation absorbing cation and a counter anion, and a polymeric binder. The salt formed between the infrared radiation absorbing cation and a tetraphenyl borate has solubility in 2-methoxy propanol at 20° C. that is greater than or equal to 3.5 g/l. The use of these infrared radiation absorbing dyes in the imageable layers provides a reduced tendency of these dyes to crystallize in the presence of tetraaryl borate counter anions.
Abstract:
A lithographic printing plate precursor comprises an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye that is defined by Structure (I) shown in the disclosure, which dyes comprise one or more ethylenically unsaturated polymerizable groups in an organic group that is attached to the methine chain. These infrared radiation absorbing dyes exhibit a reduced tendency to crystallize in the imageable layers in the presence of tetraaryl borate counter anions and therefore provide improved shelf life.
Abstract:
Imageable elements can be imaged and then processed using a solution containing core-shell particles that are designed to complex with non-coalesced particles in the non-exposed regions of imaged element. A separate development step is not needed, but the non-coalesced particles and complexed core-shell particles can be removed from the resulting printing plate before using the resulting lithographic printing plate for printing.
Abstract:
A radiation-sensitive composition for use in printing plates is described. The composition comprises: (a) at least one novolak; (b) at least one naphthoquinone diazide derivative; and (c) a copolymer comprising units A, B, and a unit C comprising a cyclic terminal urea group, wherein unit A is present in an amount of about 5 to about 50 mol % and has the formula is represented by wherein R1 is selected such that the homopolymer of A is alkali-soluble, unit B is present in an amount of about 20 to about 70 mol % and has the following formula is represented by wherein R2 is selected such that the homopolymer of B has a glass transition temperature greater than 100° C., preferably a glass transition temperature in the range from about 100 to about 380° C., and the unit C comprising a cyclic terminal urea group is present in an amount of about 10 to about 50 mol % and has the formula is represented by wherein X is a spacer group which is preferably selected from the group consisting of (a) a —(CR2)m— chain, (b) a —[CH2—CH2—O]m— chain; and (c) a —[Si(R2)—O]m— unit, wherein m is an integer greater than or equal to 1, more preferably between 2 and 12, the spacer group is connected to one of the carbon ring atoms of the cyclic urea unit or to one of the nitrogen atoms of the cyclic urea unit, and n is an integer greater than or equal to 1, more preferably between 1 and 5; and Y is a group selected from the group consisting of: wherein each R in units A, B, and C, the —(CR2)m— chain, the —[Si(R2)—O]m— unit, and group Y represents a bond between the cyclic urea and the spacer group X, or is independently selected from hydrogen, aryl, (C1-C12) alkyl, and or halogen.
Abstract:
Single layer IR-sensitive negative-working imageable elements include thermally coalesceable core-shell particles without a polymeric binder in an imageable layer. Thermal imaging causes coalescence of the particles in imaged regions while non-imaged regions can be removed with plain water or an aqueous solution containing an acidic polymer.
Abstract:
A radiation-sensitive composition for use in printing plates is described. The composition comprises: (a) at least one novolak; (b) at least one naphthoquinone diazide derivative; and (c) a copolymer comprising units A, B, and a unit C comprising a cyclic terminal urea group, wherein unit A is present in an amount of about 5 to about 50 mol % and has the formula wherein R1 is selected such that the homopolymer of A is alkali-soluble, unit B is present in an amount of about 20 to about 70 mol % and has the following formula wherein R2 is selected such that the homopolymer of B has a glass transition temperature greater than 100° C., preferably a glass transition temperature in the range from about 100 to about 380° C., and the unit C comprising a cyclic terminal urea group is present in an amount of about 10 to about 50 mol % and has the formula wherein X is a spacer group which is preferably selected from the group consisting of (a) a —(CR2)m— chain, (b) a —[CH2—CH2—O]m— chain; and (c) a —[Si(R2)—O]m— unit, wherein m is an integer greater than or equal to 1, more preferably between 2 and 12, the spacer group is connected to one of the carbon ring atoms of the cyclic urea unit or to one of the nitrogen atoms of the cyclic urea unit, and n is an integer greater than or equal to 1, more preferably between 1 and 5; and Y is a group selected from the group consisting of: and wherein each R in units A, B, and C, the —(CR2)m— chain, the —[Si(R2)—O]m— unit, and group Y is independently selected from hydrogen, aryl, (C1-C12) alkyl, and halogen.