Enzymatic opacifying composition for paper, pulp or paperboard, processes using same and pulp, paper or paperboard produced therefrom

Abstract

An organic agent for enhancing opacity in paper, paperboard or pulp comprises a hydrolase or an oxido-reductase; this enzymatic opacifying agent overcomes drawbacks associated with traditional organic and inorganic opacifying agents but also serves to provide increased strength and reduced porosity in paper and paperboard.

Description

FIELD OF THE INVENTION [0001] This invention relates to a composition for use in making paper, pulp or paperboard; and a process of making paper, pulp or paperboard employing the composition, especially to add opacity to the paper, pulp or paperboard and a paper, pulp or paperboard produced using the composition. BACKGROUND OF THE INVENTION [0002] In paper and paperboard manufacture, sheet formation is generally obtained on wire webs in a wet end from pulp slurry and is followed by the gradual removal of moisture in a press section and drier section. A calender section follows the drier section with the purpose of obtaining a desired finish, for example, smoothness, thickness or gloss. [0003] Despite the real advantages of using mechanical action to impart certain characteristics to the sheet, these advantages are limited. Complementary solutions for improving even further certain paper or paperboard characteristics can be applied internally in the wet end or externally with size-pr...

AI Technical Summary

Benefits of technology

[0096] A particular advantage of the present invention is that for a given amount of inorganic filler, if present, in the paper, paperboard or pulp, which filler may or may not have opacifying properties, the opacity is enhanced by the organic, enzymatic opacifying agent. More especially, it is not necessary to use an inorganic opacifying agent and it is not necessary to increase the content of an inorganic filler having opacifying properties in order to increase the opacity, and which increase in content would result in loss of strength. The organic, enzymatic opacifying agent of the invention not only enhances the opacity but also increases the strength and lowers the porosity.

[0097] An inorganic filler is not required in order to provide opacity when employing the organic opacity agent of the invention; and the invention contemplates paper compositions containing the opacifying agent of the invention and being free of inorganic filler, although inorganic fillers may be included in the paper composition for the traditional purpose of reducing the pulp content, without their necessity to provide an opacifying function.

[0098] The invention is further illustrated by reference to the Examples. EXAMPLES

Problems solved by technology

Despite the real advantages of using mechanical action to impart certain characteristics to the sheet, these advantages are limited.

The process disadvantages are however important and concern mostly wire, felt, doctor blade, refiners abrasion, machine deposits increase, increased linting dust, breaks related to sheet strength decrease and filler retention difficulties requiring retention program solutions.

The functional disadvantages are mostly related to increased two sidedness, reduced rigidity, increased linting and decreased sheet strength.

Despite the clear advantages traditional opacifiers bring to papermaking, functional limitations on their use related especially to paper sheet strength and porosity have been noticed in mill conditions.

Increasing the level of inorganic fillers for the majority of specific paper grades very often equates into one or more of the following disadvantages: Increased paper machine blades abrasion Increased paper machine press rolls wear Increased paper machine inorganic deposits and breaks Increased chemical costs in papermaking (e.g. when TiO2 is used) Increased printer equipment abrasion

In the prior art. it was known that increasing the levels of inorganic fillers favors opacity increase, but also results in decrease in strength.