Fiberlean Technologies Limited

Imerys Pigments, Inc.

Imerys Minerals Limited

Ecc International Limited

John Claude Husband

Per Svending

David Robert Skuse

Tafadzwa Motsi

Alan Coles

Mikko Likitalo

Christopher R L Golley

Desmond Charles Payton

Daniel John Panfil

Harry Vincent Brown, Jr

Michele Susan Renals

Jonathan Stuart Phipps

David O Cummings

Richard Bown

Christopher Nutbeem

Nigel Victor Jarvis

Dave R Skuse

Charles Desmond Payton

Pamela G Drage

Ulrika Reimer

David Frederick Bailey

Adrian Hughes

A method for preparing an aqueous suspension may include providing a fibrous substrate comprising cellulose having a Canadian Standard freeness equal to or less than 450 cm, and microfibrillating the fibrous substrate in an aqueous environment by grinding in the presence of a grinding medium consisting essentially of mullite. The grinding may be carried out in the absence of grindable inorganic particulate material. The grinding medium may be present in an amount of at least about 10% by volume of the aqueous environment. The microfibrillated cellulose may have a fibre steepness of from about 20 to about 50.

Paper filler composition

Methods of preparing partially dried or essentially completely dried compositions comprising microfibrillated cellulose and an inorganic particulate material may include microfibrillating a fibrous substrate comprising cellulose in an aqueous environment by grinding in the presence of an inorganic particulate material to form an aqueous composition comprising microfibrillated cellulose and inorganic particulate material, wherein the fibrous substrate comprising cellulose has a Canadian Standard freeness equal to or less than 450 cm, wherein the fibrous substrate to the inorganic particulate material are in a ratio of about 99.5:0.5 to about 0.5:99.5, and wherein the microfibrillated cellulose has a fibre steepness of from about 20 to about 50; by treating the aqueous composition comprising microfibrillated cellulose and inorganic particulate material to remove at least a portion or substantially all of the water of the aqueous composition to form a partially dried or essentially completely dried composition comprising microfibrillated cellulose and inorganic particulate material.

The present invention relates to compositions, such as filled and coated papers, comprising microfibrillated cellulose and inorganic particulate material.

Compositions

A paper product may include high energy thermomechanical pulp (TMP), low energy TMP, and microfibrillated cellulose. The paper product may also include inorganic particulate material. A papermaking composition suitable for making the paper product, a process for preparing the paper product, and use of microfibrillated cellulose may include high energy TMP, low energy TMP, and microfibrillated cellulose, and optionally inorganic particulate material. The microfibrillated cellulose may have a fibre steepness of from about 20 to about 50 in the paper product.

Paper composition

A paper product may include high energy thermomechanical pulp (TMP), low energy TMP, and microfibrillated cellulose. The paper product may also include inorganic particulate material. A papermaking composition suitable for making the paper product, a process for preparing the paper product, and use of microfibrillated cellulose may include high energy TMP, low energy TMP, and microfibrillated cellulose, and optionally inorganic particulate material. The microfibrillated cellulose may have a fiber steepness of from about 20 to about 50 in the paper product.

Compositions such as filled and coated papers may include microfibrillated cellulose and inorganic particulate material.

A method for preparing an aqueous suspension may include providing a fibrous substrate comprising cellulose having a Canadian Standard freeness equal to or less than 700 cm, and microfibrillating the fibrous substrate in an aqueous environment by grinding in the presence of a grinding medium which is to be removed after completion of grinding. The grinding may be carried out in the absence of grindable inorganic particulate material, wherein the grinding medium is present in an amount of at least about 10% by volume of the aqueous environment, and wherein the microfibrillated cellulose has a fiber steepness of from about 20 to about 50.

A method for preparing an aqueous suspension comprising microfibrillated cellulose and inorganic particulate material, the method comprising a step of microfibrillating a fibrous substrate comprising cellulose in an aqueous environment in the presence of an inorganic particulate material.

Paper filler method

A method of preparing a steep particle size inorganic particulate material includes grinding an aqueous suspension of an inorganic particulate material having a solids content of less than 35% and including a sub-effective amount of a dispersant for the inorganic particulate material. The method may further include dewatering the aqueous suspension to a solids content of at least 50% and dispersing the dewatered aqueous suspension by adding an additional amount of dispersant, and wherein, after grinding, the inorganic particulate material has a steepness factor above 35.

Grinding method for inorganic particulate material

A coating composition for paper and other substrates, particularly mechanical papers such as lightweight coated (LWC) paper, comprises an aqueous suspension of a particulate pigment together with a binder, wherein the particulate pigment comprises: (a) a first component which is a precipitated calcium carbonate consisting predominantly of aragonitic or rhombohedral particle shapes or of aragonitic and rhombohedral particle shapes in a weight ratio of between around 40:60 and about 60:40 (e.g. about 50:50) aragonitic:rhombohedral, and a second component which is a processed particulate hydrous kaolin clay having a shape factor greater than or equal to about 25 and a steepness greater than or equal to about 20; or (b) a first component which is a fine particulate calcium carbonate consisting predominantly of particles having a generally spherical particle shape, and a second component which is a processed particulate hydrous kaolin clay having a shape factor greater than or equal to about 45 and a mean equivalent particle diameter (d) less than about 0.5 &#x3bc;m; or (c) a first component which is a precipitated calcium carbonate consisting predominantly of aragonitic and rhombohedral particle shapes in a weight ratio of between about 40:60 and about 60:40 (e.g. about 50:50) aragonitic:rhombohedral, and a second component which is a processed particulate hydrous kaolin clay having a shape factor less than about 25.

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St. Austell, United Kingdom

John Claude Husband