Process for manufacturing board
AssigneeKemira Oyj
InventorsAarto Paren, Jukka Jakara, Ari Juppo, Reetta Strengell
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Abstract
The invention relates to a process for manufacturing liquid packaging board, in which process a board pulp is treated with a percarboxylic acid by adding to the pulp percarboxylic acid in an amount of 0.5-5 kg/ton of dry pulp, indicated as a 100 percent percarboxylic acid, whereafter, or simultaneously with the percarboxylic acid treatment, sizing is carried out with a combination of a resin size and a neutral size, which is followed by board forming. The manufactured board has good resistance to liquid penetration.
Claims11
A process for manufacturing liquid packaging board, characterized in that a board pulp is treated with a percarboxylic acid by adding to the pulp percarboxylic acid in an amount of 0.5-5 kg/ton of dry pulp, indicated as a 100 percent percarboxylic acid, whereafter, or simultaneously with the percarboxylic acid treatment, sizing is carried out with a combination of a rosin size and a neutral size, which is followed by board forming.
The method according to any of the preceding claims, characterized in that the board a pulp is mechanical pulp or an unbleached chemical pulp or a mixture thereof.
The process according to any of the preceding claims, characterized in that the percarboxylic acid is performic acid, peracetic acid or perpropionic acid, preferably distilled peracetic acid.
The process according to any of the preceding claims, characterized in that the percarboxylic acid is added to the board pulp in an amount of 1-3 kg/ton of dry pulp, indicated as a 100 percent percarboxylic acid.
The process according to any of the preceding claims, characterized in that the consistency of the board pulp in connection with the adding of percarboxylic acid is 0.1-40%.
The process according to any of the preceding claims, characterized in that the pH at the said sizing step is within the range 3-11, preferably 4-9.
The process according to any of the preceding claims, characterized in that in connection with the sizing step there is added one or more agents stabilizing the percarboxylic acid, such as a complexing agent or an alkaline-earth metal compound.
The process according to any of the preceding claims, characterized in that in connection with the sizing step there is added one or more aluminum compounds, preferably alum.
A process for improving the resistance of liquid packaging board to liquid penetration, characterized in that in connection with the manufacture of board a board pulp is treated with a percarboxylic acid by adding to the pulp percarboxylic acid in an amount of 0.5-5 kg/ton of dry pulp, indicated as a 100 percent percarboxylic acid, whereafter, or simultaneously with the percarboxylic acid treatment, sizing is carried out with a combination of a resin size and a neutral size.
Dependencies are inferred from the claim text.