Paper woodfree

An oil-based ink is capable of providing printed images with good water resistance, and making it easy to print images on a recording medium or woodfree paper having a water-resistance surface. 

High grades comprising predominantly white Hghtiy printed graphic papers and board (very often woodfree), recovered by separate collection and therefore relatively clean. 

For production of woodfree uncoated and coated fine papers up to 40 kg starch per ton of paper are applied. 3 to 10 kg starch is added at the wet end, with the aim of internal strength improvement and retention increase. The major share of the starch is added to the sheet in surface treatment. A mass balance on a typical fine paper machine has shown, that more than 90% of the added starch is retained in the final paper product. Losses occur mainly during the sheet forming process in the wire section due to insufficient retention. Starch which is not held back in the paper is discharged with the process effluents to the waste water treatment plant, where a complete biodegradation process follows. 

System for Woodfree Graphic Paper Grades and Market DIP... 

Woodfree recovered paper, such as MOW, CWF and/or UWF, is used as raw material to produce woodfree DIP grades for tissue, woodfree graphic paper grades or market DIP as a chemical pulp substitute. Table 4.4 shows the raw material quality parameters and the quahty demands on woodfree DIPs for named applications. 

TaWe 4.4 Quality parameters of European MOW/UWF/MWF mix and DIP for different woodfree graphical paper grades. 

Process control with advanced measuring techniques and control strategies allowing the operators to continuously monitor the operation, see trends in paper quality and machine condition and take appropriate action Machine speed five decades ago the typical paper machine ran at a speed of about 300-350 mmirnh Today maximum machine speeds are above 2100 m mim for tissue machines, more than 1900 m min in newsprint production and above 1550 m mim for woodfree grades ( Fig. 6.1)... 

The newest development is a single nip press section where the web is dewatered in just one nip (Fig. 6.50). With a shoe of more than 300 mm length a dryness of about 52% is reached in woodfree paper production at more than... 

Woodfree uncoated papers include, above all, office papers, which are in turn subdivided into writing and printing papers as well as copy papers. In the past, these papers were not supercalendered. Simple machine calendering was considered satisfactory. However, the demands made on the surface quality of these papers have now increased considerably. 

Single-coated, woodfree papers are generally calendered on-Hne. The machines used for this are mostly 2 x 2-roU soft calenders. At speeds up to 1300 m min Gardner gloss values of 55-65% can be achieved. To insure good flatness - this applies above aU to cut-size sheets - the papers must be subjected to only moderate linear loads. 

An example of woodfree paper is copy paper. The most important properties are high bulk at a certain roughness, and good formation. Here the whole paper-making process has to be considered to meet the high bulk requirements of the... 

Table 7.4 Woodfree oflfeet printing paper - single-coat, matt quality.

Table 7.6 Woodfree offset printing paper -quality. single-coat, gloss ...

Woodfree papers cover a very wide basis weight range. Depending on the basis weight the application can be single coat, double coat or triple coat The coat weight per layer can vary in a wide range between approximately 8 and 20 g m. ... 

WFC (woodfree coated fine papers) CP 60-120 25-35 single, double, triple 88-98 magazines, image brochures, labels... 

There has been an unbelievable development in the production of documents since the invention of printing with movable letters by Gutenberg. Within a short period of time, the necessary fibers for paper production could no longer be supplied by rags. After an intense search wood was discovered as an alternative. Ground wood pulp was used and later also chemical pulp, whereas in the latter the lignin is removed in a chemical process and so a woodfree pulp is produced. 

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