Metsa-serla Oy

Jyrki Kettunen

Petri Silenius

Anne Rutanen

Jukka Ranua

The present invention concerns a process and a coating color for coating a cellulosic web. According to the process an aqueous coating color is applied on the surface of the web. The invention comprises using a coating color which contains an aqueous polymer whose viscosity in an aqueous solution increases when the temperature rises. Preferably, methylcellulose or a corresponding polymer having a gelling temperature of about 5 to 10 .degree. C. more than the application tempature of the coating color is used. The temperature of the coating is increased after the application of the coating color in order to achieve gelling of the polymer. As a result, the coating color rapidly solidifies which decreases the amount of mixture being recycled and it reduces mist-formation in the film press method and improves coverage of coating applied by conventional blade coating.

Process and coating color for coating of paper and board

The present invention is related to a method of producing paper pulp from a fibrous raw material. According to the invention, such pulpwood is used in which the content of phenol compounds or phenolic derivatives is clearly, advantageously at least 20% lower than the average content of such compounds in the native grade of the raw material. Advantageously, the content of parahydroxy-benzoic acid (PHBA) is determined from the pulpwood and pulpwood containing low PHBA levels is used as pulping raw material. The invention also provides a method of producing pulp-wood suitable for use in the manufacture of easily bleachable paper pulp, in which method selected native specimens of pulpwood trees with an advantageously low content of phenol compounds or phenolic derivatives are produced by micropropagation, the cloned tree specimens are planted and grown to obtain pulping raw material, the pulpwood is harvested, and the pulpwood is produced into paper pulp using mechanical, chemical or chemimechanical delignification methods.

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Kirkniemi, Finland

Jyrki Kettunen