Micro-organisms are a general problem in the papermaking industry. They may be introduced into a paper making process in a number of ways. For example, micro-organisms can be carried on the wood particles which are incorporated into the paper stock. They can also be introduced into the paper stock by the web itself which serves as a vehicle for the micro-organisms. In addition, when a paper web is made on a Yankee dryer, microbial agents can be present in the air used to dry the web, and consequently can be present on the paper web after it is wet with the finishing water.
It is known that micro-organisms can cause problems which include degrading pulp, slime formation, and product defects, such as holes, pinholes, or spots, color loss, and defects in the appearance of the paper product.
Typical prior art antimicrobials used in papermaking processes to control micro-organisms include quaternary ammonium compounds such as benzalkonium chloride. These compounds are used to maintain the surfaces of paper machines and other paper processing equipment and the paper web itself in a clean and sanitary condition during the papermaking process. However, these compounds have limited effectiveness against some types of micro-organisms, and are in fact becoming ineffective due to bacterial resistance. Other biocides are also used, but their effectiveness is limited by the fact that the biocide must be in contact with the micro-organisms in order to have an effect.
One promising type of antimicrobial papermaking additive is a cationic compound which has the ability to disrupt the anionic charge of the cell wall of the micro-organism being treated. This disrupts the cell wall and results in cell death. It is believed that cationic antimicrobial agents which act in this manner are unique in that they are not attacked by bacterial enzymes which break down other types of antimicrobial agents. The cationic antimicrobial compounds are not water-soluble, and thus are not easily washed off the treated paper web and equipment.
While the cationic antimicrobial compounds are known in the art and have been used to control micro-organisms in papermaking processes, they have not been used to the fullest extent possible. It is possible to add the compounds to a paper stock in the amount of about 0.1 to about 5 mg/kg. However, if the amount of cationic compound is too low, the compound will not have a significant effect against the micro-organisms present in the system. Conversely, if be359ba680
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