Kemira Oyj

Tarja Turkki

Anneli Lepo

Elsi Turunen

Jonni Ahlgren

Helena Peuranen

Sami Puttonen

Mari Ojanen

Erland Hermansson

Sai Li

Bernhard Überbacher

Antti Matula

Eija Anneli Lepo

Bernhard ÜBerbacher

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 method of producing a surface sizing composition, the method comprising: providing a metal salt having at least 3 valence electrons, wherein the metal salt is selected from the group of aluminium sulfate, aluminium chloride, aluminium nitrate, polyaluminium sulfate (PAS), polyaluminium chloride (PAC), and polyaluminium chloride sulfate (PACS), polyaluminium formiate, polyaluminium nitrate, and any combination thereof; providing an aqueous polymer dispersion, wherein the aqueous polymer dispersion is an aqueous polymer dispersion (A) and an aqueous prepolymer composition (B), wherein the aqueous polymer dispersion (A) is obtainable by free radical emulsion copolymerizing a first ethylenically unsaturated monomer blend, and wherein the aqueous prepolymer composition (B) is obtainable by free radical emulsion copolymerizing in a polymerization solvent comprising C1-6-carboxylic acid and C1-6-carboxylic acid anhydride, a second ethylenically unsaturated monomer blend; and mixing the metal salt and the aqueous polymer dispersion to provide a surface sizing composition to be used in papermaking.

Surface sizing composition, method of production, and use thereof

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

A coating structure for a sheet-like substrate, which includes lignocellulosic fibres is disclosed. The structure includes at least one pre-coat layer including at least 70 weight-% of a first styrene (meth)acrylate copolymer polymerised in the presence of a stabiliser, having a glass transition temperature Tg &#x2264;20&#xb0; C. preferably &#x2264;10&#xb0; C., &#x2264;30 weight-% of inorganic platy mineral particles and 0.01-2 weight-% of at least one first thickener. The coating structure further includes a top coat layer including at least 50 weight-% of a second styrene (meth)acrylate copolymer polymerised in the presence of a stabiliser having a glass transition temperature Tg &#x2264;20&#xb0; C. preferably &#x2264;10&#xb0; C., &#x2264;30 weight-% of inorganic mineral particles, 0.01-5 weight-% of at least one second thickener and 0.5-30 weight-% of an antiblocking agent. Further disclosed is a sheet-like product coated with the coating structure.

The present invention relates to a surface sizing composition comprising a metal salt, wherein the metal has at least 3 valence electrons, and an aqueous polymer dispersion, wherein the aqueous polymer dispersion is an aqueous polymer dispersion (A) obtainable by free radical emulsion copolymerizing a first ethylenically unsaturated monomer blend comprising (a) 0 to 75% by weight of at least one optionally substituted styrene, (b) 15 to 100% by weight of at least one C1-C4-alkyl (meth)acrylate, and (c) 0 to 10% by weight of other ethylenically unsaturated copolymerizable monomers, wherein the sum (a)+(b)+(c) is 100%, in the presence of a water-soluble redox system comprising a first free radical initiator for the free radical emulsion copolymerization and an aqueous prepolymer composition (B) obtainable by free radical emulsion copolymerizing in a polymerization solvent comprising C1-6-carboxylic acid and C1-6-carboxylic acid anhydride, a second ethylenically unsaturated monomer blend comprising (i) 5 to 50% by weight of at least one ethylenically unsaturated quaternary amine selected from quaternary salt of N,N,N-tri(C1-4-alkyl)amino C1-4-alkyl(meth)acrylate with a mineral acid or an organic acid and/or quaternary salt of N,N,N-tri(C1-4-alkyl)amino C1-4-alkyl(meth)acrylamide with a mineral acid or an organic acid, (ii) 0 to 40%, preferably 0%, by weight of at least one ethylenically unsaturated tertiary amine selected from N,N-di(C1-4-alkyl)amino C1-4-alkyl(meth)acrylate and/or N,N-di(C1-4-alkyl)amino C1-4-alkyl(meth)acrylamide, (iii) 10 to 95% by weight of at least one optionally substituted styrene, (iv) 0 to 50% by weight of at least one C1-C4-alkyl (meth)acrylate, and (v) 0 to 10% by weight of other ethylenically unsaturated copolymerizable monomers, wherein the sum (i)+(ii)+(iii)+(iv)+(v) is 100%, in the presence of a second free radical initiator, and adding water to the obtained polymer dispersion to obtain the aqueous prepolymer composition. The present invention further relates to production thereof and use on cellulosic materials.

A water-based barrier coating composition suitable for use as a barrier coating is disclosed which includes an aqueous polymer composition obtainable by free radical (co)polymerizing an ethylenically unsaturated monomer blend having an optionally substituted styrene, at least one C1-C4-alkyl (meth)acrylate, other ethylenically unsaturated copolymerizable monomers, degraded starch polyvinyl alcohol (PVA), a plasticizer; a composition having C16-C18 alkenyl ketene dimer, optionally as a mixture with rosin, of a gelling agent; and optionally a filler.

Water-based barrier coatings

Provided herein is an aqueous polymer dispersion (A) obtainable by free radical emulsion copolymerizing a first ethylenically unsaturated monomer blend having 15 to 100% by weight of at least one C1-C4-alkyl (meth)acrylate, in the presence of a water-soluble redox system having a first free radical initiator for free radical emulsion copolymerization and an aqueous prepolymer composition (B) obtainable by free radical emulsion copolymerizing in a polymerization solvent having C1-6-carboxylic acid and C1-6-carboxylic acid anhydride a second ethylenically unsaturated monomer blend with 5 to 50% by weight of at least one ethylenically unsaturated quaternary amine, and 10 to 95% by weight of at least one optionally substituted styrene, in the presence of a second free radical initiator.

Cationic surface sizing agent

The present invention relates to a sizing agent composition comprising starch, lignosulfonate and poly(alkyl acrylate), poly(alkyl (meth)acrylate), a mixture of poly(alkyl acrylate) and poly(alkyl methacrylate) or a copolymer of alkyl acrylate and alkyl (meth)acrylate. The present invention further relates to a method for preparing the sizing agent composition, and use of the sizing agent composition for sizing paper, paper products or board.

Method for producing a sizing agent composition, a sizing agent composition and use thereof

The present invention provides a core/shell polymer particle for surface sizing of cellulosic products, wherein the core polymer and the shell polymer of the core/shell polymer particle are polymerized from monomers comprising at least 40%, by weight of monomers selected from branched C3-10-alkyl (meth)acrylate, styrene, linear C1-10-alkyl (meth)acrylate, and acrylonitrile, based on the total weight of the monomers of the core/shell polymer particle; provided that the polymer of the core/shell polymer particle comprises at least 40% by weight of branched C3-6-alkyl (meth)acrylate and at least 50% by combined weight of branched C3-10-alkyl (meth)acrylate and styrene, linear C1-10-alkyl (meth)acrylate, and/or acrylonitrile, based on the total weight of the monomers of the core/shell polymer particle.

Core/shell polymer particles as surface sizing agents

The invention relates to a coating color composition for paper and/or paperboard comprising a pigment, optionally known additives used in coating compositions, and a binder substitute comprising styrene acrylate copolymer having mean particle size &#x2266;100 nm. The invention also relates to paper or paperboard coated with a coating color composition according to the invention.

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Helsinki, Finland

Tarja Turkki