Kemira Oyj

Other

Helena Peuranen

Anneli Lepo

Tarja Turkki

Perttu Heiska

Kimmo Huhtala

Erland Hermansson

Nina Bruun

Sami Puttonen

Mari Ojanen

A coating structure for a sheet-like substrate is disclosed including cellulosic fibres and a sheet-like product. The structure includes at least one pre-coat layer and a top coat layer, where the pre-coat layer(s) and the top coat layer include 10-90 weight-% of a styrene (meth)acrylate copolymer which is polymerised in the presence of a stabiliser, and which has a glass transition temperature Tg≤20° C., preferably ≤15° C., more preferably ≤13° C. Furthermore, the pre-coat layer(s) includes a polysaccharide, such as starch, and the top coat layer includes 5-60 weight-% of at least one water-soluble coating binder, which is selected from polysaccharides and polyvinyl alcohols, as well as at most 5.0 weight-% of a cross-linker, which reacts with —OH or —COOH groups.

Coating structure, sheet-like product and its use

A barrier coating composition is disclosed including 30-70 weight-% of a styrene (meth)acrylate copolymer, polymerised in the presence of a stabiliser, and the styrene (meth)acrylate copolymer having a glass transition temperature Tg&#x2264;20&#xb0; C., preferably &#x2264;10&#xb0; C., 30-70 weight-% of a polyvinyl alcohol, and at most 5.0 weight-% of a cross-linker, reacting with &#x2014;OH or &#x2014;COOH groups. Further disclosed is a sheet-like product coated with the coating composition.

Barrier coating composition, sheet-like product and its use

The invention relates to a composition for modifying rheology of coating colour and its use. The composition comprises an aqueous polymer dispersion, comprising a copolymer of monomer (a), which is at least one optionally substituted styrene, and monomer (b), which is at least one C1-C4-alkyl (meth)acrylate. The copolymer has a particle size D50&#x3c;100 nm. Composition comprises also degraded starch having an average molecular weight Mn&#x3c;1000 g/mol.

Composition for modifying rheology of coating color, its use and a coating color

The invention relates to an aqueous polymer dispersion having a viscosity of &#x2264;150 m Pas at 40% solids content and comprising polymer particles having a particle size D50 less than 85 nm. The polymer dispersion is obtainable by free radical emulsion copolymerisation of at least monomer (a) and monomer (b), where monomer (a) is at least one optionally substituted styrene and monomer (b) is at least one C1-C4-alkyl (meth)acrylate, in a reaction mixture comprising degraded starch which has an average molecular weight Mn&#x3c;1000 g/mol. The invention relates also to the use of the polymer dispersion and method for preparing it.

Aqueous polymer dispersion, its use and method for preparing aqueous polymer dispersion

The present disclosure relates to a method for controlling size distribution of formed polymer particles during preparation of aqueous polymer dispersion. The method comprises obtaining an aqueous polysaccharide solution, which comprises about 10 to 40 weight-% polysaccharide containing a free hydroxyl group, such as starch, and polymerising in the polysaccharide solution in the presence of a graft-linking, water-soluble redox system about 30 to 60 weight-% of at least one optionally substituted styrene, about 60 to 30 weight-% of at least one C1-C4-alkyl(meth)acrylate, and 0 to about 10 weight-% of other ethylenically unsaturated copolymerizable monomers. The size distribution of the formed polymer particles is controlled by adjusting viscosity of the polysaccharide solution before the polymerisation to a level less than about 20 mPas.

Method for controlling size distribution of polymer particles during preparation of aqueous polymer dispersion and aqueous polymer dispersion

The present disclosure relates to a method for controlling size distribution of formed polymer particles during preparation of aqueous polymer dispersion. The method comprises obtaining an aqueous polysaccharide solution, which comprises about 10 to 40 weight-% polysaccharide containing a free hydroxyl group, such as starch, and polymerising in the polysaccharide solution in the presence of a graft-linking, water-soluble redox system about 30 to 60 weight-% of at least one optionally substituted styrene, about 60 to 30 weight-% of at least one C1-C4-alkyl (meth)acrylate, and 0 to about 10 weight-% of other ethylenically unsaturated copolymerizable monomers. The size distribution of the formed polymer particles is controlled by adjusting viscosity of the polysaccharide solution before the polymerisation to a level less than about 20 mPas.

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Espoo, Finland

Helena Peuranen