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The table shows how the two systems rate high-brightness papers, but there is no simple way to convert between the two systems because the test methods are so different. [4] The ISO rating is higher and can be over 100. This is because contemporary white paper incorporates fluorescent whitening agents (FWA). Because the ISO standard only ...
In the production of white paper, the wood pulp is bleached to remove any color from the trace amounts of lignin that was not extracted in the chemical pulping process. There are three predominant methods of bleaching: Elemental chlorine bleaching uses chlorine and hypochlorite.
If white paper is desired, bleaching uses peroxides or hydrosulfites to increase the brightness of the pulp. The bleaching methods are similar for mechanical pulp, but the goal is to make the fiber brighter.
Elemental chlorine free (ECF) is a technique that uses chlorine dioxide for the bleaching of wood pulp.It does not use elemental chlorine gas during the bleaching process and prevents the formation of dioxins and dioxin-like compounds, carcinogens.
The pulp produced up to this point in the process can be bleached to produce a white paper product. The chemicals used to bleach pulp have been a source of environmental concern, and recently the pulp industry has been using alternatives to chlorine, such as chlorine dioxide, oxygen, ozone and hydrogen peroxide.
A precursor to the soda pulping process was the paper making process developed by Matthias Koops in 1801 which involved washing wood shavings in limewater, adding soda crystals and then boiling the mixture. [2] Soda pulping was one of the first chemical pulping methods and was invented in 1851 by Burgess (United States) and Watts (England).
Put a paper towel inside the container and close the lid. Shake it vigorously for 30 seconds and rinse it clean. Vinegar Method. Fill your container with white vinegar. Let it sit for two to three ...
Early method of bleaching cotton and linen goods on lawns A bleach worker. The textile bleaching (or bleaching of textiles) is one of the steps in the textile manufacturing process. The objective of bleaching is to remove the natural color for the following steps such as dyeing or printing or to achieve full white. [1]