Manufacture and use of a composite structure containing precipitated carbonate

Abstract

A precipitated carbonate polysaccharide structure which, when used as a filler, improves the structural strength of paper or board, or gypsum boards, plastics or gums, among others, as well as the stiffness level and optical properties (brightness and opacity) of the paper or board, together or separately with other fillers; carbonates, in particular. The invention further improves the setting of printing ink on the surface of the paper or board. The invention also includes the manufacturing method of the precipitated carbonate polysaccharide structure.

What is claimed is: 
     
         1 . A composite structure that is formed of polysaccharide and carbonate, wherein the body of the structure is made of polysaccharide, into which carbonate has been precipitated. 
     
     
         2 . The composite structure according to  claim 1 , wherein the polysaccharide is starch, cold-soluble starch, carboxy-methyl cellulose, guar gum or nanocellulose or a mixture of any of the above, most preferably starch or nanocellulose, whereby the shape of the polysaccharide body is preferably swollen or partly or fully broken. 
     
     
         3 . The composite structure according to  claim 1 , wherein the precipitated carbonate is calcium or magnesium carbonate or a combination thereof, and at least part of the carbonate is preferably precipitated directly on the polysaccharide body from the solution. 
     
     
         4 . The composite structure according to  claim 3 , wherein part of the carbonate is added carbonate, which is preferably calcium carbonate, such as precipitated calcium carbonate (PCC) or ground calcium carbonate (GCC) or a mixture thereof. 
     
     
         5 . The composite structure according to  claim 1 , being produced by the method of forming a carbonate ion solution; mixing polysaccharide, in a form having free hydroxyl groups on its surface, into the carbonate ion solution, whereby a carbonate polysaccharide slurry is formed; and precipitating carbonate salt from the slurry into the polysaccharide. 
     
     
         6 . Use of the composite structure according to  claim 1  as filler in the manufacture of paper or board, in plastics, gums, the manufacture of gypsum board or the manufacture of laminates that are made of Deco paper. 
     
     
         7 . The use according to  claim 6 , wherein, in the manufacturing process of paper or board, the composite structure is dosed into the pulp together with ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), kaolin agglomerates, carbonate agglomerates, kaolin carbonate agglomerates or any of the above-mentioned mixtures. 
     
     
         8 . The use according to  claim 6 , wherein, in the paper or board machine, the composite structure is either dosed into high-consistency or dilute pulp before the paper or board is formed in the wire section. 
     
     
         9 . The use according to  claim 6 , wherein printing paper, packing board, tissue paper, kraft paper or another paper grade is manufactured, employing mechanical pulp or chemical pulp fibre.