EP0570461A1 - Composition pour plaques d'impression appliquee avant la cuisson - Google Patents

Composition pour plaques d'impression appliquee avant la cuisson

Info

Publication number
EP0570461A1
EP0570461A1 EP19920904701 EP92904701A EP0570461A1 EP 0570461 A1 EP0570461 A1 EP 0570461A1 EP 19920904701 EP19920904701 EP 19920904701 EP 92904701 A EP92904701 A EP 92904701A EP 0570461 A1 EP0570461 A1 EP 0570461A1
Authority
EP
European Patent Office
Prior art keywords
acid
organic acid
salt
tetrasodium
composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19920904701
Other languages
German (de)
English (en)
Inventor
Thomas J. Dooley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sun Chemical Corp
Original Assignee
Sun Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sun Chemical Corp filed Critical Sun Chemical Corp
Publication of EP0570461A1 publication Critical patent/EP0570461A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/08—Damping; Neutralising or similar differentiation treatments for lithographic printing formes; Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/26—Processing photosensitive materials; Apparatus therefor
    • G03F7/40—Treatment after imagewise removal, e.g. baking

Definitions

  • a type of radiation sensitive materials known as photopolymers become less soluble after exposure to radiation and therefore a negative transparency is used in the exposure. In this case, it is the non-radiation-exposed areas that are removed upon development and the radiation-exposed areas that remain on the substrate form the image.
  • suitable photopolymers include diazo resins chromium-sensitized colloids, diazonium or azide-sensitized resins or polymers bearing such groups. Plates having a radiation sensitive layer based on such materials are known as negative-working plates.
  • Radiation sensitive materials such as those based on
  • orthoquinone diazides become more soluble after exposure to radiation and therefore a positive transparency is used in the exposure. In this case, it is the radiation-exposed areas that are removed by development and the non-radiation-exposed areas that remain on the substrate form the image. Plates having such radiation sensitive layers are known as positive-working plates.
  • the life, in terms of the number of copies it can produce, of a printing plate can often be increased by baking the plates, i.e.
  • Patent 1,154,749 heating at a temperature sufficient to harden resin-reinforced image areas causes those areas of the substrate revealed on development to be at least partially covered with a contaminating layer which is ink accepting and which would therefore cause scumming and yield a soiled background during printing. This layer must therefore be removed before printing is initiated and this is achieved in accordance with the teachings of the patent by treating the plate with aqueous alkaline solution.
  • U.S. Patent 4,294,910 discloses the use of various aqueous compositions known as "gumming" or "pre-bake” solutions to avoid problems resulting from the burning-in process.
  • Such solutions contain materials such as sodium dodecyl phenoxybenzene disulfonate and the sodium salts of alkylated naphthalene sulfonic acid, sulfonated alkyl diphenyl oxide, methylene dinaphthalene disulfonic acid, etc.
  • burning-in process is not, as a rule, discernible to the naked eye and it is difficult to ensure that all the contamination has been removed.
  • contamination may be present in the pores as a result of residual material left behind from the development process. Such contamination is likely to even cause scumming during long printing runs as the substrate surface is gradually worn away.
  • the alternative of redeveloping the plates after burning-in in order to remove the contaminating layer is costly and inconvenient since the plates have to be returned to the plate fabrication facility after they have been removed from the oven.
  • pre-bake gum solution It is important to consider the requirements for an effective pre-bake gum solution.
  • the components of the solution must act to clean or even seal the porous aluminum oxide surface. Indeed, such cleaning must occur with precision around the fine image structure of the printing plate.
  • the components of the pre-bake gum must also not attack the coating that constitutes the image area. Such components must not only avoid penetration to the base or near to the base, but must also avoid the creation of serious irregularities in the coating surface. Deficiencies occurring during the pre-bake process can bring about coating failure under the stress of press conditions.
  • the aqueous composition of the present invention provides superior pre-bake protection while allowing for a wide latitude of coating thickness.
  • the superior properties in comparison to the prior art compositions arise out of a better coating integrity during lay-down on the plate surface as well as during pyrolysis (i.e. during "burning-in”).
  • the anionic surfactant component of the composition of this invention has a viscosity depressant property and also has a unique wetting activity that increases markedly (i.e. 10-30 fold) with temperature.
  • the present invention involves the use of an aqueous
  • composition which is applied to the surface of the developed plate prior to burning- in.
  • the composition acts as a protectant in preventing contamination from occurring during burning-in and thereby obviates the necessity for redeveloping the plate.
  • the unique improvement of the invention lies in an increase in the latitude of application, i.e. in the permitted variation in coating thickness, such as occurs in the manual application of the pre-bake gum solution.
  • the potassium-sodium salt combination is preferred for several reasons. First, it results in a marked color change to brown when the plated is baked. This color change is helpful to the printer since it offers an immediate indication as to whether the plate has been baked. It has also been found that the combination of potassium and sodium salts causes a retention of film integrity during drying and pyrolysis (i.e. the baking or "burning-in" step). The result is a smooth, unmarked plate coating surface after baking and washing. When the salts were exclusively sodium, tiny cracks occurred in the film during drying and baking, resulting in areas having a linear wave-like surface pattern, which indicated a coating attack.
  • the strong organic acid may contain C 8 - C 40 straight or branched chain alkyl, alkaryl, aralkyl, aryl or aryl ether groups and includes acids such as n-decyl (sulfophenoxy) benzenesulfonic acid, oxybis (n-decylbenzenesulfonic acid), a mono-or di-alkyl straight or branched chain derivative of naphthalenesulfonic acid having 1 to 4 carbon atoms in the alkyl group, methylene di-naphthalenedisulfonic acid, dodecyl benzenesulfonic acid,
  • acids such as n-decyl (sulfophenoxy) benzenesulfonic acid, oxybis (n-decylbenzenesulfonic acid), a mono-or di-alkyl straight or branched chain derivative of naphthalenesulfonic acid having 1 to 4 carbon atoms in the al
  • the alkyl group contains 1 to 4 carbon atoms, dodecyl (sulfophenoxy) benzenesulfonic acid, oxybis (dodecylbenzenesulfonic acid), hexadecyl (sulfophenoxy) benzenesulfonic acid, oxybis (hexadecylbenzenesulfonic acid) and mixtures thereof.
  • the strong organic acid comprises a mixture of n-decyl (sulfophenoxy) benzenesulfonic acid and oxybis (n-decylbenzenesulfonic acid).
  • anionic surfactants include tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinamate, tetrasodium N-1,2-dicarboxyethyl)-N-dodecylsulfosuccinamate, tetrasodium N-(1,2-di-carboxyethyl-N-butylsulfosuccinamate), tetrasodium N-(1,2-dicarboxyethyldicarboxyethyl)-N-amyloxypropylsulfosuccinamate, tetrasodium N-(ß-hydroxyethyl)-N-(sulfo-2,5-endomethylenehexahydrophthalylate) aspartate, sodium N-methyl-N-cocoyl taurate and mixtures thereof.
  • the preferable anionic surfactant is tetras
  • the salt of the strong organic acid will be present in an amount of 1 to 12 wt.%., preferably 3 to 8 wt.%, while the salt of the anionic surfactant will be present in an amount of 1 to 10 wt. %, preferably 2 to 6 wt.%.
  • the weak organic acid may be selected from the group consisting of citric acid (which is preferred), isomalic acid, glycolic acid, malonic acid, tartronic acid, malic acid, glyceric acid, tartaric acid, tricarballylic acid, and 1,2,3,4-butanetetracarboxylic acid.
  • the salt of the weak organic acid comprises potassium citrate.
  • the salt of the weak organic acid is generally employed in an amount of 0.5 to 12 wt.%, preferably 1 to 9 wt.%.
  • the components of the aqueous composition should be such that they do not volatilize at the burning-in temperature, and are selected according to the nature of the substrate, radiation sensitive layer, and the purpose for which the plate is to be used. For example, in the case where a lithographic printing plate is being produced, the selected component must not only be an effective physical barrier, but it must also be such that it does not
  • compositions of the present invention are easily applied to the surface of the developed plate by conventional methods, e.g. spraying, dipping, brushing, etc. and provide the desired protective shield.
  • the shield can be readily removed from the plate merely by wiping the plate with water. This removal step can be effected while the plate is actually mounted on the printing press., and thus the plate need not be returned to the plate-making facility after completion of the burning-in procedure. Rinsing with water to remove the shield and desensitizing with, e.g. gum arable, is all that is then required to make the plate ready for printing.
  • a pre-sensitized radiation sensitive plate comprising a metallic substrate and a radiation sensitive layer comprising an organic photosensitive compound may be processed by the steps of:
  • composition of the present invention to provide a water- soluble layer overlying the revealed substrate and the previously-exposed radiation sensitive layer not removed during the developing step;
  • compositions The first was to study the effect of a thick layer of the aqueous composition on the plate coating and also to determine the efficacy of the composition in cleaning-sealing the base. The second was to study the precision of cleaning-sealing around the complex patterns of a test picture. All plate evaluations were carried out with positive-working plates.
  • test plate consisted of a 12.7 ⁇ 25.4 cm section of which about 2.5 - 3.8 cm were exposed. The entire plate was developed and wiped to dryness or near-dryness. The exposed area was treated with several milliliters of aqueous composition which were
  • a wipe was soaked with the aqueous composition and the excess squeezed out.
  • the resultant moist pad was wiped onto the large section to give a thick, uniform layer. This layer was not subsequently buffed.
  • the plate was then allowed to air-dry.
  • the exposed buffed area i.e. the thin layer
  • the unexposed area (i.e. the thick layer) had a solution coating weight of 12 to 16 g/m 2 .
  • the test plate consisted of a 20 x 28 cm section. About 2.5 - 5.0 cm were unexposed and the remainder of the plate was exposed using a gray scale and in a test picture having varied and complex texturing and details. The plate was developed and wiped to near- dryness. Thereafter, a suitable quantity of the test solution was applied and carefully rubbed in. The plate was then buffed to near- dryness and was allowed to air-dry. The coating weight of solution applied at this point was about 3.5 - 4.0 g/m 2 . The treated plate was heated in a laboratory oven at about
  • IA-SP Greater streaking Rough coating. Lightened textures with white areas of penetration.
  • Example 1 a comparison was made of the commercially available composition of Example 1 which contains the branched dodecyl sulfonate salts and an aqueous composition that contains the straight chain decyl sulfonate salts as well as the preferred sulfosuccinamate surfactant.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
  • Printing Plates And Materials Therefor (AREA)

Abstract

L'invention se rapporte à une composition aqueuse servant à protéger des plaques d'impression lithographiques présensibilisées exposées à un rayonnement lumineux actinique. Cette composition comprend une quantité efficace de: (a) un sel d'ammonium, sodium, potassium ou lithium d'un acide organique fort, et (b) un sel d'ammonium, sodium, potassium ou lithium d'un agent tensio-actif anionique qui contient les fonctions du sel d'un acide organique fort et du sel d'un acide organique faible, ainsi que (c) un sel d'ammonium, sodium, potassium ou lithium d'un acide organique faible. Cette composition est appliquée à la surface des plaques après le développement de celles-ci, mais avant qu'elles soient cuites, de façon à empêcher la contamination de ces surfaces qui risquerait de se produire en raison du traitement thermique.
EP19920904701 1991-01-30 1992-01-09 Composition pour plaques d'impression appliquee avant la cuisson Withdrawn EP0570461A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US64790991A 1991-01-30 1991-01-30
US647909 1991-01-30

Publications (1)

Publication Number Publication Date
EP0570461A1 true EP0570461A1 (fr) 1993-11-24

Family

ID=24598739

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920904701 Withdrawn EP0570461A1 (fr) 1991-01-30 1992-01-09 Composition pour plaques d'impression appliquee avant la cuisson

Country Status (4)

Country Link
EP (1) EP0570461A1 (fr)
JP (1) JPH06505207A (fr)
CA (1) CA2100082A1 (fr)
WO (1) WO1992014190A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2510907A (en) * 2013-02-19 2014-08-20 Krefting & Sandstrom Lifeclean Ab New compositions

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3539992A1 (de) * 1985-11-12 1987-05-14 Hoechst Ag Einbrenngummierung fuer offsetdruckplatten
CA1329719C (fr) * 1987-07-31 1994-05-24 Tadao Toyama Plaque d'impression lithographique et methode de traitement connexe
GB8827813D0 (en) * 1988-11-29 1988-12-29 Vickers Plc Improvements in/relating to processing of radiation sensitive members
US5021324A (en) * 1990-10-05 1991-06-04 Polychrome Corporation Printing plate protectant

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9214190A1 *

Also Published As

Publication number Publication date
JPH06505207A (ja) 1994-06-16
CA2100082A1 (fr) 1992-07-31
WO1992014190A1 (fr) 1992-08-20

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