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

Definitions

• the present invention relates to liquid compositions which can be used for constituting the wetting water of offset plates; it also relates to the wetting waters obtained using the compositions according to the invention.
• offset plates have, on their surface, aquaphile parts and encrophilic parts.
• the aquaphile parts When these plates are brought into contact with water or solutions containing water and with ink, the aquaphile parts are covered with a thin film of water and the ink-absorbing parts are covered with a film ink. These films of water and ink are then, via a rubber roller called “blanket”, transferred to the paper which is thus "printed"
• aqueous product As an aqueous product which can be used to produce these water films, water or a mixture of water and at least one alcohol (isopropyl alcohol) is most often used. It is also known that this aqueous product may contain certain additives such as, for example, glycerin and / or sodium phosphates and / or bactericides which prevent any development of algae.
• the aqueous product to be used should advantageously have very specific characteristics so as to, on the one hand, maintain improved stability despite the possible transfer of products from the paper and / or the plate. offset and, on the other hand, to carry out a control as precise as possible of the thickness of said film of water and therefore of the water-ink balance during transfer to the paper.
• an appropriate surface tension depends. the dampening system used on the printing machine.
• said surface tension will preferably be chosen between 44 and 52 10 -3 N / m.
• said surface tension will preferably be between 32 and 37 10 - 3 N / m, it being understood that, by means of a suitable choice of the solution used for wetting, the quantity of d alcohol as usually used. If necessary, an adjustment of the surface tension of the aqueous solutions can be obtained by adding an appropriate additive (such as a non-foaming surfactant known to specialists).
• the desired buffer effect should be as effective as possible; certain preferred preparations of the invention make it possible, for the same test, to obtain variations in pH of less than 0.5 unit.
• the preparations used can consist either, preferably, of a single product, or of a mixture of products.
• a single product it has been found that said product must be a salt (previously formed or formed within the solution) of an organic carboxylic acid with an organic base (amine).
• an organic acid with an acid constant (expressed in pKa) between 3 and 6 will be used.
• the monoacids have proved to be of little interest; polyacids will therefore be used which may have complementary functional groups, for example hydroxyl groups, as organic base, mono or polyamines (primary, secondary or tertiary amines or polyamines, such as hydrazine or ethylenediamine or amines cy cliques, or amino alcohols); these.
• amines will have a Basicity constant (pKb) between 2 and 9 and more particularly between 3 and 6.
• pKb Basicity constant
• the acid salt of citric acid and dimethylamine mention will be made in particular of the acid salt of citric acid and dimethylamine.
• This preparation can be marketed in any form; however, it will preferably be marketed in the form of an additive for fountain water which will be directly usable by the printer.
• This additive will comprise, in the form of an aqueous solution, in addition to the preparation described above, a hygroscopic product and optionally at least one light alcohol which will serve to compatibilize the various ingredients of said additive:
• the hygroscopic product which may either be glycerin , either an equivalent polyol such as a polysaccharide or one of its derivatives (for example carboxymethylcellulose) or a polymerization product of vinylpyrrolidone, or a colloidal silicic acid, serves to maintain the quantity of water deposited on the plate and the blanket given in particular that, due to the relatively low surface tension of the solutions used, the film of water on the plate and the blanket is particularly thin. Another important technical consequence of this minimal need for water is that the drying of the prints is accelerated.
• the additive for wetting water may also include various products such as bactericides, fungicides or products used for self-cleaning of the blanket with respect to the ink such as, for example, N-methylpyrrolidone.
• This additive for fountain water will be in the form of an aqueous solution and will have a concentration of active products (preparation, hygroscopic product, surfactant, etc.) such as generally from 1 to 10% of this additive is used in l dampening water.
• the salt obtained by condensation of 1 mole of citric acid (in its monohydrate form) with 2 moles of dimethylamine was used as a buffer preparation.
• the salt obtained by condensation of 1 mole of citric acid monohydrate with 2 moles is used as a buffer preparation. ethanolamine.
• the salt obtained by condensation of 1 mole of malic acid per 1.1 mole of dimethylamine was used as a buffer preparation.
• the salt obtained by condensation of 1 mole of citric acid monohydrate per 2 moles of cyclohexylamine was used as a buffer preparation.
• the salt obtained by condensation of one mole of adipic acid with one mole of piperidine was used as a buffer preparation.
• composition A or of composition B depends on the experimental conditions, in particular on the hardness of the water.
• the additives described above are sold so as to be used in an amount of 1 to 6 parts by weight of this additive (per 100 parts of water).
• additives are advantageously used after adding a suitable amount of water, namely, for example, 4 parts of additives per 100 parts of water.

Landscapes

• Printing Plates And Materials Therefor (AREA)
• Detergent Compositions (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9279581

Family Applications (2)

Family Applications Before (1)

Country Status (8)

Cited By (2)

Families Citing this family (4)

Citations (4)

Family Cites Families (3)

• 1982
  • 1982-11-26 FR FR8219911A patent/FR2536675A1/fr not_active Withdrawn
• 1983
  • 1983-11-18 WO PCT/US1983/001839 patent/WO1984002142A1/en unknown
  • 1983-11-18 JP JP84500418A patent/JPS59502097A/ja active Pending
  • 1983-11-18 AU AU24122/84A patent/AU576748B2/en not_active Ceased
  • 1983-11-18 EP EP84900335A patent/EP0126773A1/de not_active Withdrawn
  • 1983-11-24 EP EP83402270A patent/EP0112745A1/de not_active Withdrawn
  • 1983-11-25 DK DK541683A patent/DK541683A/da not_active Application Discontinuation
  • 1983-11-25 CA CA000441981A patent/CA1251881A/en not_active Expired
  • 1983-11-25 MX MX199538A patent/MX161896A/es unknown

Patent Citations (4)

Non-Patent Citations (2)

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