Filler compositions and their use in papermaking
First Claim
1. An improved process for the manufacture of a fibrous sheet material by dewatering an aqueous slurry of fibers, and in which (a) filler particles are added to the aqueous slurry, before the dewatering, wherein the improvement is characterized by first making a filler/fiber composition of the filler particles (a) with (b) synthetic organic hydrophobic fibers by treating the fibers (b) with the filler particles (a) and with (c) a polymer that coats the fibers (b) and functions as a coupling agent between the filler particles (a) and the said fibers (b), and then incorporating said filler/fiber composition in the aqueous slurry.
1 Assignment
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Accused Products
Abstract
A filler composition that is suitable for use in the manufacture of paper, board, wet-laid non-wovens or other fibrous sheet materials comprises (preferably flocculated) filler particles (e.g. mineral fillers such as clay, talc or calcium carbonate) attached to fibres (e.g. synthetic organic fibres such as polyester or aramid fibres) by means of a coupling agent. These fibres generally have an average fibre length of 4 mm or more. Suitable coupling agents include oligomeric and other polymeric materials such as modified starch, cellulose ethers and derivatives thereof, modified natural gums, ketene dimers or poly(vinyl alcohol). Colloidal silica or colloidal bentonite clay may also be included. The filler composition is preferably added to the stock before the latter reaches the flowbox of the sheet-making machine. The invention allows high levels of filler to be achieved while maintaining satisfactory strength properties, in particular tear strength, in the sheet.
136 Citations
8 Claims
- 1. An improved process for the manufacture of a fibrous sheet material by dewatering an aqueous slurry of fibers, and in which (a) filler particles are added to the aqueous slurry, before the dewatering, wherein the improvement is characterized by first making a filler/fiber composition of the filler particles (a) with (b) synthetic organic hydrophobic fibers by treating the fibers (b) with the filler particles (a) and with (c) a polymer that coats the fibers (b) and functions as a coupling agent between the filler particles (a) and the said fibers (b), and then incorporating said filler/fiber composition in the aqueous slurry.
Specification