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
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/54—Starch

Definitions

• the invention relates to a printing paper according to the preamble of claim 1, which is to be used in particular for offset or gravure printing. Furthermore, the invention relates to a method for producing the printing paper and its use.
• DE-AS 12 21 893 describes the production of coated printing papers, starch being made partially cold-soluble by mechanical treatment in a pan mill, so that it is still dissolved in the drying after the coating process by the evaporating water of the coating slip and in a dissolved or gelatinized form in a manner known per se. as a binder to fix the pigments like chalk.
• the papers produced are certified to have a high gloss. The problem of the rub resistance of the printing inks is not addressed.
• banknote paper is known in which to avoid fiber detachment and to increase the resistance to soiling, the surface is provided with a coating which contains 0.5 to 10 parts by weight of very fine rice starch and, if appropriate, further inorganic pigments from a special plastic binder. The problem of abrasion resistance does not arise with such papers.
• Matte printing papers have the great advantage that, on the one hand, the printed products produced with them do not produce any annoying light reflections and, on the other hand, in conjunction with suitable printing inks, the actual printing, in particular the multi-color printing, has a very excellent printing gloss, which increases the quality of the printing product.
• Calcium carbonate has been widely used in the past few years to produce such matt-coated printing papers.
• Scrub resistance is understood to mean the resistance of an ink layer against mechanical stress due to pressure load and friction during the further processing of the printed sheets and when using the finished printed products.
• the object of the present invention is therefore to provide a matt-coated printing paper which has improved abrasion resistance and reduced susceptibility to glossy strips.
• the invention provides the characteristic features of a printing paper according to the preamble of claim 1.
• Claims 2 to 9 identify preferred design options for the printing paper.
• a method for producing the matte coated printing paper is specified in claims 10 and 11 and the use of the printing paper in claim 12.
• non-gelatinized starch granules which are practically present as a coating pigment in the coating in an amount of 10 to 65% by weight, based on the dry content of the coating for taking up the printing ink, the coating being a further pigment Calcium carbonate contains, a paper suitable for the production of high-quality printing work can be produced, the rub resistance and susceptibility to gloss streak development is significantly improved.
• coated paper according to the invention can now also be used to provide smooth, but non-glossy papers for the gravure printing process, as are required in particular for printed products with long runs.
• the printing paper according to the invention preferably contains starch granules whose gelatinization temperature is increased by chemical modification known per se. Such a modification is very preferably achieved by the starch granules designated in the characterizing part of claims 3 and 4, the gelatinization temperature being able to be influenced by the choice of the degree of etherification or esterification.
• the size of the starch granules is expediently chosen depending on the average size of the calcium carbonate pigment. Starch granules with an average grain diameter of 7 ⁇ m to 50 ⁇ m are preferred, but starch granules with an average grain diameter of 15 to 25 ⁇ m are particularly preferred.
• the selection can be made using the known separation techniques, such as hydrocyclone separation according to DE-OS 2341570. In particular, the following may be considered as non-gelatinized starch granules: corn, potato, wheat, rye, rice or tapioca starch. However, corn or potato starches are particularly preferred since they are sufficiently available and inexpensive.
• the line for taking up the printing ink can also contain other white pigments known and customary in paper coating technology.
• Common coating kaolins, titanium dioxide to increase whiteness and opacity, satin white to increase whiteness, gypsum as an inexpensive pigment from flue gas desulphurization plants, talc, but also known synthetic pigments based on silicate, aluminum oxide or plastic can also be used.
• the proportion of these pigments should expediently not exceed 15% by weight, based on the solids content of the coating, with all proportions, including binders and auxiliaries, adding up to 100% by weight.
• a method according to the invention for producing the printing paper according to the invention consists in the fact that a conventional coating base paper with a basis weight of
• the coating composition in addition to calcium carbonate, also containing 10 to 65% by weight of unglazed starch granules contains on their solids content.
• the coating slip contains 5 to 14% by weight, preferably less than 10% by weight, of conventional binders such as plastic latices, gelatinized, degraded starch or other known binders from paper coating technology, dispersants, optionally further white pigments and viscosity regulators.
• the solids content of this coating slip is set to 40 to 72% by weight, preferably 55 to 63% by weight.
• the viscosity of this coating slip is set to 500 to 4000 m Pas, measured with the Brookfield viscometer, spindle no. 4 at 50 rpm. A higher viscosity for the roll order and a lower viscosity for the doctor blade, air brush or blade application are preferred, it being possible to adjust the viscosity by adding customary, known water-soluble polymers, such as polyvinyl alcohol, carboxymethyl cellulose or polyacrylic acid derivatives.
• the pH of the coating slip to be applied is 8 to 10, preferably 8.8 to 9.2 and is adjusted during the preparation of the coating slip, if necessary by adding alkali.
• the non-gelatinized starch When preparing the coating slip, it has proven to be particularly preferred to add the non-gelatinized starch to the batch as the last component in order to avoid excessive shear of the starch granules. If higher amounts of starch granules are added to the batch, it is advisable to increase the proportion of inorganic or organic dispersants to 0.5 to 1 part by weight, since it has been shown that native, non-gelatinized starch results in a dilatant flow behavior of the coating slip.
• the paper coated with it is dried to a final moisture content of 92 to 96% dry using known drying processes, such as IR emitters, hot air floating dryers or cylinder dryers, and then trimmed to the desired roll or format width.
• coated paper produced in this way is to be used for gravure printing, it is subjected to a calender treatment known per se, with 2 to 8 roller nip passes producing the necessary smoothness on the paper at a line pressure of 50 to 400 da N / cm, without a noticeable increase in gloss to cause.
• a common primer formulation contains, for example, 100 parts by weight of ground chalk with a grain size of 70% ⁇ 2 ⁇ m, 10 parts by weight of oxidized, gelatinized starch and 9 parts by weight of a styrene-butadiene plastic binder as a binder, as well as other auxiliaries for pH and viscosity control as calcium carbonate pigment .
• the solids content of such a primer is depending on the application of the primer from 55 to 72 % By weight atro adjusted, the line application per side being chosen between 6 to 15 g / m atro.
• the method according to the invention can be used to produce matt papers coated on one or both sides.
• plastic latex binder 0.5 parts by weight of urea formaldehyde resin
• the coated papers each have one
• the pick test was determined in accordance with the information sheet for the IGT device, and the evaluation was carried out using a rating scale from 1 to 6.
• the unsaturated patterns of Examples 1 to 3 and the comparative example were used to produce proofs with a defined amount of ink, so-called weighed proofs, with the test printing device from fürbau. After the printing ink had dried through for at least 24 hours, the abrasion resistance test was carried out using the Oser abrasion resistance tester under defined conditions. The printed surface is rubbed against the same side or the back of the Paper, each unprinted, for a period of 3 minutes with a load of 625 g. The assessment can be made visually or by contrast measurement with the Elrepho device at the unprinted point. The visual assessment with a grade of 1 to 6 resulted in the following classification of the examples:
• the examples according to the invention have a substantially lower gloss than the comparative example, both in the unsatinated and in the satin state, and that the so-called matt effect increases with increasing proportion of native undisturbed starch in the coating slip, without the susceptibility of the unsatinated dried line increases to form gloss streaks.
• the coated paper is satinized, on the one hand the gloss does not increase significantly above the value of the unsatinated comparative example, but on the other hand a sufficient smoothness increase can be achieved which makes the printing paper according to the invention suitable for the gravure printing process.

Landscapes

• Paper (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6368639

Family Applications (1)

Country Status (5)

Cited By (3)

Families Citing this family (3)

Citations (2)

• 1988
  • 1988-12-07 DE DE3841199A patent/DE3841199A1/de not_active Withdrawn
• 1989
  • 1989-12-01 ES ES199090900830T patent/ES2035747T3/es not_active Expired - Lifetime
  • 1989-12-01 DE DE9090900830T patent/DE58902391D1/de not_active Expired - Lifetime
  • 1989-12-01 WO PCT/EP1989/001428 patent/WO1990006399A2/de active IP Right Grant
  • 1989-12-01 EP EP90900830A patent/EP0447471B1/de not_active Expired - Lifetime
• 1991
  • 1991-06-05 FI FI912707A patent/FI98235C/sv active

Patent Citations (2)

Also Published As

Similar Documents

Legal Events