Web printing paper and process for producing it

Details Web printing paper and process for producing it Web printing paper and process for producing it

1995-09-21

1998-05-19

Ozaja, Donald E.

Paper making and fiber liberation

Processes and products

With coating after drying

162137, 162147, 162183, 1621811, 1621817, 1621576, 428341, 428342, 428331, D21H 1114, D21H 1984, D21H 1936

Patent

active

057530777

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a web printing paper, which has a base paper containing mineral filler, recycled fibers and, as applicable, mechanical pulp and/or chemical pulp, and a coating on both sides containing pigment and binder. Furthermore, the invention relates to a process for producing the web printing paper.


BACKGROUND OF THE INVENTION

Basically, there are three main groups of press papers:
The above-mentioned papers are used in the production of daily newspapers, illustrated periodicals, magazines, catalogs and advertising circulars, such as those usually included with daily newspapers or illustrated periodicals.
In the past, there were many attempts to improve the quality of these papers while at the same time reducing production costs. This led to upgraded newsprint being used in areas which originally were reserved for the higher-value SC papers; in turn, SC papers of improved quality could be used where only LWC papers had been used in the past.
An overview of the current press papers may be found in the "Paper Manufacturing Weekly" (Wochenblatt fur Papierfabrikation) 9 (1988), pp. 337-344. This study also describes a film press used to apply preparations to the paper types in question. SC papers and LWC papers are largely printed by the offset or gravure process, while newsprints and upgraded newsprints are printed almost exclusively by the offset process. Because the papers mentioned are supplied to the printing machine exclusively in the form of webs, they are also referred to collectively as "web printing papers." In this study, the fiber composition of known European wood-containing offset papers is given as 4 to 50% chemical pulp, remainder: mechanical pulp. The ash content of newsprints is given as 0 to 7%, and for SC papers 18 to 25%. The use of recycled fibers is not addressed.
The authors Bergh and Svenka report in the "Paper Manufacturing Weekly" 16 (1990), pp. 701-708 and in "Pulp and Paper Canada" 92: 4 (1991), pp. 52-58 on the surface treatment of newsprint with starch or pigmentations in order to improve printability. Even a surface treatment carried out solely with starch leads, at a applied coat of 1 g/m.sup.2, to improved surface binding, resulting in a paper suitable for multicolor offset printing. The reduced whiteness, however, was disadvantageous. When, instead, a starch solution based on calcium carbonate or kaolin and preparations containing 70% by weight starch ester, relative to the pigment, were applied with a so-called film press, a quality of improved strength and printability was created that could no longer be termed newsprint. Depending on the selected satinage conditions--super-calendar (SC) or soft-compact-calendar (SCC)--smoothness values between a maximum of <200 (SCC) and 1,000 Bekk/sec. (SC) were obtained. The base paper used for the starch/pigment application contained TMP (thermo-mechanical pulp) as its main fiber components and an ash content of 0.4% weight.
The article: "The Production of High-Quality Upgraded Newsprint by an On-Machine Surface Treatment with LAS (Liquid Application System)," Eucepa Conference Proceedings (1988), pp. 538-555 reports on the surface treatment of newsprint with starch, CMC or other film-formers and on the application of a lightly pigmented coating. The produced product is to said to fall between LWC and SC papers. The application of the surface preparation is, according to the article, carried out with the devices known as short-swell coaters or LAS. Better base papers, in respect to strength, can be coated using the short-dwell system, while papers of lower strength can only be processed on an LAS device. If pigmented preparations are used, they have compositions of 50% coating kaolin and 50% finely-ground calcium carbonate and contain binder shares of between 50 and 200 parts by weight, relative to 100 parts by weight pigment. If latex is also used as a binder, its share of the total binder quantity is 10%. The prepared papers are subsequently treated on a super-calendar. If only star

REFERENCES:
patent: 4298652 (1981-11-01), Suzuki et al.
patent: 4425405 (1984-01-01), Murakami et al.
patent: 4478910 (1984-10-01), Oshima et al.
patent: 5302437 (1994-04-01), Idei et al.
"Moglichkeiten zum On-line-Streichen von hochgefullten, holzhaltigen Papieren"; Glittenberg et al.; Wochenblatt fur Papierfabrikation, 13, 1992, pp. 505-515.
"Pigmentieren mit der Filmleimpresse"; Rantanen; Wochenblatt fur Papierfabrikation 6, 1992, pp. 193-197.
"Zur Ordnung der Verfahren der mechanischen Zerfaserung von Holz" Blechschmidt; Zellstoff und Papier 37, 1988, pp. 212-213.
Wochenblatt Fur Papierfabrikation, 9, 1988, pp. 337-344; "Studie uber Bindemittelsysteme fur LLWC-und MFP-Papiere" N.O. Bergh et al.
Wochenblatt Fur Papierfabrikation, 16, 1990 pp. 701-708; "Oberflachenbehandlug von Zeitungsdruckpapier . . . " N.O. Bergh, et al.
"Upgrading of newsprint by surface treatment" Bergh et al.; Pulp & Paper Canada 92:4 (1991) pp. 52-58.
"The Production of High Quality Upgraded Newsprint By An On Machine Surface Treatment with LAS", Akesson et al; Eucepa Conference Proceedings (1988) pp. 538-555.
"Improving the quality of newsprint with fillers" Koppelman et al.; Tappi Journal, Nov. 1986 pp. 74-78.
"Oberflachenbeschichtete SC-Papiere, eine Herausforderung fur LWG-Papiere"; Baumeister et al.; Wochenblatt Fur Papierfabrikation, 1, 1988, pp. 1-6.

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