A method for controlling the deposition of stickies in pulping and papermaking processes

Abstract

A method for controlling the deposition of stickies in pulping and papermaking processes. The method comprises adding to fibre pulp or stock an additive comprising an organo-modified siloxane comprising units of the formula: [R<1>ZSiO<(4-a-b) / 2>]n in which each R<1> is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group, and each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or preferably at least one or more groups -R<2>-(OCpH<2p>)<q>(OC<r>H<2r>)<s>-R<3>, wherein the n is an integer greater than 1; the a and the b are independently 0, 1, 2 or 3; the R<2> is an alkylene group or a direct bond; the R<3> is a group as defined for the R<1> or the Z above; the p and the r are independently an integer from 1 to 6; the q and the s are independently 0 or an integer such that 1 <= q + s <= 400. Each molecule of the organo-modified siloxane contains at least one group Z. The organo-modified siloxane is preferably a hydroxyl- or alkyl- endcapped linear polydimethylsiloxane, in which 5 to 18 mole percents of silicon atoms are substituted by the Z groups of the formula -R<2>-(OCH<2p>)<q>(OC<r>H<2r>)<s>-R<3>, wherein the p is 2, the r is 3, the q and the s are independently 10 to 20, the R<2> is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and the R<3> is a hydrogen atom or a hydroxyl, alkoxy, ester or ether group.

Description

technical field [0001] The present invention relates to a method for controlling sticky deposition in pulp and papermaking processes. Background technique [0002] The problems associated with the formation of sticky deposits (comprising both inorganic and organic components) in pulp and papermaking processes are well known. "Pitch", "stickies" and "white-pitch" are terms commonly used for the sticky hydrophobic material produced in these processes that mechanically adheres to surfaces and forms aggregates body. [0003] In pulping processes using virgin fibers, "bitumen" generally refers to a natural resinous hydrophobic material comprising fatty acids, esters and sterols derived from natural raw materials, most often wood. Bitumen is particularly prevalent in the mechanical grade pulps commonly used for recycled paper, where it undergoes hydrolytic degradation and saponification to a lesser extent than the alkaline kraft process used to make chemical pulps. [0004] Pap...

AI Technical Summary

Problems solved by technology

These changes may also limit the types of techniques available to overcome problems caused by stickies deposition

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