Patent ID: 8343312

Claim:
A process for making a filler-containing paper or product thereof, comprising: dispersing at least one inorganic pigment and at least one polymer in water to obtain a first aqueous suspension; milling said first aqueous suspension in a ball mill to obtain a second aqueous suspension comprising a polymer-pigment hybrid as a filler; optionally drying said second aqueous suspension to obtain a dried polymer-pigment hybrid; optionally redispersing the dried polymer-pigment hybrid in water; adding said second aqueous suspension or the dried polymer-pigment hybrid redispersed in water to a paper stock; and draining the paper stock to obtain a sheet, wherein said at least one polymer is a polydiene consisting of from 10 to 90% by weight of an aliphatic hydrocarbon having two double bonds, from 10 to 90% by weight of a vinylaromatic compound, from 0 to 20% by weight of an acid monomer, and from 0 to 20% by weight of a further monomer, or a polyacrylate consisting of from 10 to 95% by weight of a C 1 -C 10 -alkyl (meth)acrylate, from 0 to 60% by weight of a vinylaromatic compound, from 0 to 20% by weight of an acid monomer, and from 0 to 10% by weight of a further monomer, and wherein the milling of said first aqueous suspension is carried out in the presence of a polyethylene wax, said wax comprising, in copolymerized form, from 26.1 to 39% by weight of at least one ethylenically unsaturated carboxylic acid, and from 61 to 73.9% by weight of ethylene.