Search results
Results from the WOW.Com Content Network
Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process. [20]
It was not until the introduction of wood pulp in 1843 that paper production was independent of recycled materials. [2] Recycling of used paper before the industrialisation of paper production, rag paper was recycled to make low-grade board. A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth ...
Recycled paper products can also contain BPA, [65] although this can depend strongly on how it is recycled. Deinking can remove 95% of BPA, [9] with the pulp produced used to make newsprint, toilet paper and facial tissues. If deinking is not performed then the BPA remains in the fibers, paper recycled this way is usually made into corrugated ...
Paper chemicals designate a group of chemicals that are used for paper manufacturing, or modify the properties of paper. These chemicals can be used to alter the paper in many ways, including changing its color and brightness, or by increasing its strength and resistance to water. [1] The chemicals can be defined on basis of their usage in the ...
The use of wood to make pulp for paper began with the development of mechanical pulping in the 1840s by Charles Fenerty in Nova Scotia [1] and by F. G. Keller [2] in Germany. Chemical processes quickly followed, first with Julius Roth 's use of sulfurous acid to treat wood in 1857, followed by Benjamin Chew Tilghman 's US patent on the use of ...
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 ...
The claim: Donald Trump can't travel to Canada because he is a convicted felon. A Dec. 3 Threads post (direct link, archive link) offers a theory as to why Canadian Prime Minister Justin Trudeau ...
The focus of the project was on chemical modification of the paper made recycled fibres, investigating the possibility to transfer wood fibre modifications technique from the wood sector to paper and packaging sector. The aim was to enhance the properties of papers and of the packaging, as the recycling process causes the deterioration of fibres.