Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/38—Coatings with pigments characterised by the pigments
  • D21H19/40—Coatings with pigments characterised by the pigments siliceous, e.g. clays
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/38—Coatings with pigments characterised by the pigments
  • D21H19/385—Oxides, hydroxides or carbonates
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/38—Coatings with pigments characterised by the pigments
  • D21H19/42—Coatings with pigments characterised by the pigments at least partly organic

Definitions

• the present invention relates to a paper capable of gravure printing, comprising at least on one side a line provided for receiving the printing ink, which contains mineral pigment and synthetic resin binders.
• Gravure-capable papers of the type specified above are known and are used, for. B. used as a print medium for illustrated magazines, mail order catalogs, advertising brochures or packaging material. Most of the papers are coated on both sides, with a primer and then the top coat intended to hold the printing ink being applied. Since, as is known, the failure of the printed image in a paper printed by the gravure printing process depends to a large extent on the surface of the coated paper, in particular on the smoothness and flatness of the line, papers intended for gravure printing are usually calendered, usually using so-called supercalenders. Despite the most careful selection of the raw material components used, in particular of the coating pigments and binders can often not always meet the high demands placed on rotogravure printing paper.
• mising dots are understood to mean unprinted imperfections which arise as a result of slight unevenness in the paper surface in that the web to be printed does not lie exactly against the gravure printing form, so that the printing ink located in the cups of the gravure form is not sucked out of the cups and White spots form in the print image due to the lack of printing ink.
• hydro- and oxycelluloses have already been used instead of finely ground cellulose fibers as a vegetable filler for the production of art print or chrome papers.
• This document does not refer to an improvement in the printability of gravure-capable papers "which are provided with a line containing mineral pigments and synthetic resin binders.
• the object of the present invention is to provide a paper capable of gravure printing, in which the printability is improved and in which in particular the number of "missing dots" that occur is significantly reduced.
• the invention provides an intaglio paper that is at least on one Page has a line intended for receiving the printing ink, which contains mineral pigment and synthetic resin binder, the line additionally containing finely ground cellulose fibers.
• the proportion of cellulose fibers present in the coating is 5 to 30% by weight, based on the total pigment proportion.
• both the mineral pigment components and the cellulose fibers are added to the total pigment component.
• the average fiber length of the cellulose fibers is between 10 and 30 ⁇ m.
• the production of cellulose fibers ⁇ 10 lim is relatively uneconomical due to the grinding effort, whereas a fiber length> 30 ⁇ m leads to problems when applying the coating, in particular by means of a doctor blade, as a result of the accumulation of the longer fibers in the coating machine application.
• the average fiber diameter is preferably in the range of 10 to 20 ⁇ m.
• the term “line” defines the line that receives the printing ink, often also called the top line.
• the paper can have a so-called primer, to which the stroke (top coat) is then applied.
• the information on the binder content is to be understood as an indication of the dry weight proportions.
• cellulose fibers present in the coating is below 5% by weight, there is no appreciable improvement in printability. Amounts of up to 30% by weight of cellulose fibers have proven to be particularly advantageous, particularly in the production of matt paper. In contrast, a proportion of cellulose fibers in the range from 5 to 15% by weight has been found to be particularly suitable for normally glossy papers.
• the mineral pigment used is calcium carbonate in an amount of 70 to 85% by weight, to which 15 to 30% by weight of finely ground cellulose fibers are added, whereby complete all information to 100% by weight total pigment.
• a binder - based on 100 parts by weight of the total pigment content - come 3.5 to 10% by weight of a synthetic resin binder, e.g. B. an aqueous plastic dispersion z. B. based on acrylate or butadiene-styrene, for use.
• Calcium carbonate in which between 50 and 70% by weight calcium carbonate particles are less than 2 lim, has proven to be a particularly suitable mineral pigment in the production of so-called matt papers in combination with finely ground cellulose fibers.
• a line composition in which the mineral pigment consists of kaolin has proven to be suitable for a normally glossy, gravure-printable paper, having a gloss value of 40 to 55% measured according to Lehmann at 75 °, whereby this mineral pigment fraction comprises 85 to 95% by weight of the makes up the entire pigment content of the coating, while the remaining 5 to 15% by weight of the pigment fraction consist of 5 to 15% by weight of finely ground cellulose fibers.
• the binder content is in the range from 3.5 to 10% by weight, based on 100 parts by weight of total pigment.
• a composition of 10 to 90% by weight of calcium carbonate and 90 to 10% by weight of kaolin has been found according to a further well-suited embodiment of the invention mineral pigment content 85 to 95 % By weight of the total pigment content and 5 to 15% by weight of finely ground cellulose fibers are added to the mixture of calcium carbonate and kaolin.
• the binder content is 3.5 to 10% by weight, based on 100 parts by weight of total pigment.
• the pigment content of the coating for a gravure-capable paper having a normal gloss consists of a mixture of calcium carbonate and / or kaolin and talc, these mineral pigments accounting for 85 to 95% by weight of the total pigment content of the coating and the rest 5 to 15% by weight of the pigment fraction consist of 5 to 15% by weight of finely ground cellulose fibers.
• the pigment content of a gravure-capable paper having a normal gloss is composed of 85 to 95% by weight from a mixture of: 40 to 70% by weight calcium carbonate and / or kaolin and 30 to 60% by weight talc, wherein the remaining 5 to 15% by weight of the pigment fraction consist of finely ground cellulose fibers and the binder content is 3.5 to 10% by weight, based on 100 parts by weight of the total pigment.
• An advantage of the above formulation is that the use of calcium carbonate in coating formulations for gravure-sensitive papers is improved, which results in a higher whiteness sets.
• the gravure-printable papers according to the present invention include the so-called LWC (light-weight-coated) papers with a basis weight (including the line on the front and back) of less than 60 g / m 2 , with an application weight of 8 on each line up to 12 g / m 2 is not required.
• LWC light-weight-coated
• a precoat can preferably be applied, the pigment content of which consists only of calcium carbonate and which is then covered by a top coat according to the invention of 8 to 12 g / m 2 on one or both sides.
• 10 to 50% by weight of the synthetic resin binder can be replaced by starch as the binder.
• the stroke is preferably applied with a doctor knife.
• cellulose fibers as a coating component have already been used in the production of so-called pressure-sensitive recording papers to protect the microcapsules containing dye precursors used in these papers in order to protect the microcapsules from premature destruction, but it is due to that Hand that the so-called pressure-sensitive recording papers are not capable of gravure printing, because the sensitive microcapsules would be destroyed during the printing process.
• the present invention therefore expressly excludes pressure-sensitive recording papers.
• a coating slip is produced in which the
• the cellulose fibers have an average fiber length of 20 ⁇ and an average fiber thickness of 15 tons.
• 5% by weight (dry weight fractions, based on the total pigment fraction) of a self-thickening, aqueous synthetic resin dispersion are used as binders.
• the coating slip is applied with an application weight of 10 g / m 2 and side onto a base paper with a basis weight of 37 g / m 2 by means of a doctor blade and, after drying, is subjected to a supercalender satin coating in the usual way.
• Example 1 prepared, but the pigment content increases
• Example 2 40% by weight consists of talc.
• the coated paper is applied and produced in accordance with Example 1.
• Pigment consists of calcium carbonate, in an amount of 8 g / m 2 and side is provided
• a coating slip is produced in which the pigment fraction consists of 90% by weight of kaolin and 10% by weight of finely ground cellulose fibers, as stated for example 1.
• the amount and type of binder, application weights and production of the paper correspond to the information given in Example 1.
• Example 3 The procedure is as described for Example 3 above, but the pigment fraction is 100% by weight kaolin.
• the table below shows the values for gloss, smoothness, heliotest and sliding friction coefficient measured on the papers produced.
• An intaglio printing plate filled with printing ink, the grid area of which has an increasing cell depth, is rolled off with a constant pressure on a test strip.

Landscapes

• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Paper (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Sheet Holders (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6450591

Family Applications (1)

Country Status (7)

Cited By (11)

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Citations (3)

Family Cites Families (1)

• 1992
  • 1992-01-30 DE DE4202598A patent/DE4202598C1/de not_active Expired - Fee Related
• 1993
  • 1993-01-15 DK DK93902211.7T patent/DK0624213T3/da active
  • 1993-01-15 WO PCT/EP1993/000087 patent/WO1993015270A1/de active IP Right Grant
  • 1993-01-15 EP EP93902211A patent/EP0624213B1/de not_active Expired - Lifetime
  • 1993-01-15 DE DE59300352T patent/DE59300352D1/de not_active Expired - Fee Related
  • 1993-01-15 ES ES93902211T patent/ES2074926T3/es not_active Expired - Lifetime
  • 1993-01-15 AT AT93902211T patent/ATE125015T1/de not_active IP Right Cessation
• 1994
  • 1994-07-25 FI FI943494A patent/FI114326B/fi not_active IP Right Cessation

Patent Citations (3)

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