Hydroxyalkylcellulose as additive in pigmented metering size press coatings
View Patent ↗Pigmented coated paper is prepared by adding a water-soluble hydroxyalkylcellulose (HAC) with an alkyl moiety of 1 to 4 carbons, or water soluble alkylhydroxyalkylcellulose (AHAC) with an alkyl hydrophobe of 1 to 24 carbons to a pigmented wet coating formulation in an amount equal to or greater than 0.15 parts HAC or AHAC based on pigment content of the coating and applying the pigmented wet coating formulation to a moving paper web via roller metering size press, wherein the use of HAC or AHAC in the pigmented coating significantly reduce misting of the coating during application as compared to the control condition with no HAC or AHAC added.
1. A process for preparing coated paper comprising a) adding a water-soluble hydroxyalkylcellulose (HAC) having an alkyl moiety of 1 to 4 carbons to a pigmented wet coating formulation in an amount 0.2 to 0.8 parts HAC based on 100 parts of pigment in the coating and b) applying the pigmented wet coating formulation to a moving paper web via roller metering size press.
2. The process of claim 1 , wherein the alkyl in the water-soluble hydroxyalkylcellulose has 2 to 3 carbons.
3. The process of claim 1 , wherein the water-soluble hydroxyalkylcellulose is hydroxyethylcellulose.
4. The process of claim 1 , wherein the pigment is selected from the group consisting of calcium carbonate and kaolin clay.
5. The process of claim 1 , wherein the pigmented wet coating formulation contains 100 parts pigment, 10 to 18 parts binder, 0.2 to 0.8 parts HAC, and 20 to 60% solids based on the total weight of the binder and pigment.
6. The process of claim 5 , wherein the solids content is 50 to 60% by weight.
7. The process of claim 5 , wherein the binder is starch or a latex.
8. The process of claim 7 , wherein the latex is a styrene based.