Abstract:
The invention is directed to compensating for imaging aberrations that result from repeated passes by an imaging laser array. The aberrations may result from swath lines formed by thermal heating and from the ruling and screen angle of the image. The techniques described herein reduce the undesirable aberrations in thermal laser generated images by breaking up and/or reducing the swath lines. In general, the techniques provide for overlapping swaths and providing masking for one or both passes that print the overlapped region.
Abstract:
A process for making thermally imageable negative working compositions comprising the steps of: (1) providing a patterning composition layer on a substrate, said patterning composition comprising: (a) at least one acid generator which is sensitive to UV radiation; (b) at least one cross-linking resin or compound; (c) at least one binder resin comprising a polymer containing at least one reactive pendent group consisting of hydroxyl, carboxylic acid, sulfonamide, alkoxymethylamide and mixtures thereof; and (d) at least one infrared absorber; (2) subjecting the patterning composition layer to a two-stage radiation exposure; (a) one stage being a flood UV-exposure; and (b) the other stage being a imagewise infrared exposure stage; (3) treating the exposed patterning composition with heat energy; and (4) developing the heat treated, exposed patterning composition with an aqueous alkaline developer to remove the non-imaged areas of the patterning composition and leaving the imaged areas substantially unaffected.
Abstract:
The present invention provides an imageable composition, which includes an acid curable composition, an acid generator, an infrared absorber, optionally a colorant, such as, a colorant dye or colorant pigment, wherein at least one of the infrared absorber and the colorant has a counter anion derived from a non-volatile acid, and further optionally, a strong acid. The present invention further provides an imageable element, which includes a substrate and an imageable composition according to the present invention coated on a surface of the substrate. Also provided is method of producing an imaged element according to the present invention.
Abstract:
A coating solution useful in the preparation of printing plate precursors comprises: a) a radiation sensitive composition C comprising a phenolic resin; b) at least one thermoplastic polymer P which has a solubility in aqueous alkaline media ranging from sparingly soluble to insoluble; c) a first solvent component A which is capable of solubilizing both composition C and thermoplastic polymer P; d) a second solvent component B having a volatility less than component A, wherein component B is capable of volatilizing composition C but not thermoplastic polymer P, and composition C and thermoplastic P are homogeneously dissolved in a mixture of components A and B; and e) at least one further polymer AP having a higher molecular weight than the phenolic resin of composition C, wherein polymer AB is miscible with the phenolic resin and immiscible with thermoplastic polymer P. The coating provides a radiation-sensitive layer for the substrate, and the coating contains homogeneously distributed thermoplastic polymer particles.
Abstract:
A method of producing a printing plate comprises: (a) providing a printing plate precursor comprising a topmost etchable first layer and a second layer located below the first layer, wherein the first and second layers have different affinities for at least one printing liquid; (b) imagewise providing atomized fluid particles in an interaction zone located above the surface of the first layer; and (c) imagewise directing laser energy into the interaction zone, wherein the laser energy has a wavelength which is substantially absorbed by the atomized fluid particles in the interaction zone, and the absorption of the laser energy causes the atomized fluid particles to imagewise impart kinetic energy to and etch the first layer. Lithographic and flexographic printing plates may be prepared according to this method, including waterless plates, negative-and positive-working plates, and processless plates.
Abstract:
The present invention provides a photosensitive lithographic printing plate which displays superior ink receptivity and superior film strength of the photosensitive layer (image area). The photosensitive lithographic printing plate is produced by providing, on top of a support, a photosensitive composition comprising a fluororesin having a fluoro aliphatic group of 3 to 20 carbon atoms in which at least two of three terminal hydrogen atoms are substituted for fluorine atoms, and an ethylene based unsaturated group, as well as a negative photosensitive compound.
Abstract:
The present invention includes an imageable element, which can be: (a) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; a polyvinyl acetal binder; and a sheet substrate; or (b) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; and a sheet substrate. The imaging layer includes a total aromatic diazonium salt containing compound content of at least 10 weight percent. The molar ratio of the aromatic diazonium salt containing compound having an alkoxy substituent to the aromatic diazonium salt containing compound that is free of an alkoxy substituent is from about 1.0:1 to 70:1. Upon imagewise exposure and development, an imaged element is obtained.
Abstract:
A method for manufacturing a microporous film comprising the steps of: (a) providing a first polymer which is a hydrophobic thermoplastic polymer and a second polymer which is a hydrophilic polymer or copolymer of N-vinylpyrrolidone; (b) dissolving said first and second polymers in a solvent system which is compatible with both polymers, said solvent system comprising a blend of an aprotic organic solvent and an alcohol; (c) coating the resulting solution on a support; (d) effecting at least a partial drying of the resulting coating; and (e) washing the coating in an aqueous medium so as to extract at least 50% by weight of the said second polymer. Image accepting members comprising a microporous film made by the above method, and preferably comprising a support which is also microporous.
Abstract:
A novel fluorinated aromatic acetal polymer comprises at least one unit of A and at least one unit of B or C, or at least one unit of each of A, B and C and optionally further comprises at least one unit of either D or E or at least one unit of each of D and E, wherein the units A and B and/or C, and optionally D and/or E are linked together by single covalent C-C bonds and have the formulae: 1 wherein RA is H or C1-C11 alkyl, or an aryl group that does not contain fluorine, and RB and RC are an aryl groups that contain fluorine. The polymer is prepared by reacting a hydrolyzed polyvinyl acetate polymer or copolymer with at least one non-fluorinated aldehyde component, and at least one fluorinated aromatic component. The polymer is useful is preparing a photosensitive composition which comprises at least one diazo resin and at least one such fluorinated aromatic acetal polymer. Such a photosensitive composition may be applied to a support to form an imageable member which may be imaged to form a lithographic printing plates.p
Abstract:
A polyvinyl acetal copolymer compound comprises the units A, B, C and D, wherein A is present in an amount of 0.5 to 30 wt.-% and is of the formula 1 wherein R is hydrogen, C1-C6 alkyl, nullCHnullCHCOOH or 2 B is present in an amount of 5 to 35 wt.-% and is of the formula 3 C is present in an amount of 10 to 55 wt.-% and is of the formula 4 wherein R1 is an alkyl group with up to 4 carbons, which is optionally substituted by an acid group, or a phenyl group to which an acid group is attached, wherein the phenyl group optionally comprises 1 to 2 further substituents selected from halogen atoms, amino, methoxy, ethoxy, methyl and ethyl groups, or is a group ZnullNR2nullCOnullYnullCOOH, wherein Z is an aliphatic, aromatic or araliphatic spacer group, R2 is hydrogen or an aliphatic, aromatic or araliphatic moiety and Y is a saturated or unsaturated chain- or ring-shaped spacer group, and unit C may have one or more occurrences in the copolymer with various moieties R1 independent of one another; and D is present in an amount of 10 to 40 wt.-% and is of the formula 5 wherein X is C1-C6 alkylene, a 5 or 6 membered saturated carbocyclic moiety optionally substituted with one or more substituents selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy or halogen, a 5 or 6 membered saturated heterocyclic moiety which comprises in the nucleus one or more heteroatoms selected from oxygen, nitrogen and sulfur, or a group of the formula I 6 wherein n is an integer from 0 to 4 and each R3 is independently selected from the group consisting of C1-C4 alkyl, halogen or C1-C4 alkoxy. A radiation-sensitive composition useful in a lithographic printing plate comprises (i) the above-described polyvinyl acetal copolymer; and (ii) a light-to-heat transformer compound.