Paper making and fiber liberation – Processes and products – Non-fiber additive
Patent
1995-08-23
1998-04-28
Chin, Peter
Paper making and fiber liberation
Processes and products
Non-fiber additive
1621646, 1621682, 162183, 106401, 106499, D21H 1769
Patent
active
057440018
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aqueous pigment slurries which contain up to 80% by weight of a finely divided pigment in dispersed form and from 0.1 to 5% by weight of at least one dispersant, processes for the preparation of the aqueous pigment slurries and the use of the pigment slurries as additives to the paper stock in the production of filler-containing paper.
2. Discussion of the Background
Concentrated aqueous pigment slurries are required in industry, for example for the preparation of paper coating slips. In order to be able to prepare highly concentrated aqueous pigment slurries having a low viscosity, a dispersant is required. Known dispersants are, for example, low molecular weight polyacrylic acids (cf. EP-B-0 002 771, which discloses a process for the preparation of low molecular weight polyacrylic acids).
Furthermore, U.S. Pat. No. 3,945,843 discloses that copolymers of methyl acrylate and acrylic acid are suitable as dispersants for the preparation of highly concentrated pigment slurries, such as calcium carbonate slurries. The pigment slurries have solids contents of from 50 to 80% by weight and are used for coating paper.
EP-B-0 194 621 discloses that, for the production of filler-containing papers, aqueous pigment slurries which contain from 40 to 80% by weight of a pigment in which the particle diameter of from 40 to 90% of the particles are less than 2 .mu.m and from 0.1 to 2% by weight, based on the pigment, of a copolymer which contains esters of acrylic acid or methacrylic acid and at least one ethylenically unsaturated C.sub.3 -C.sub.5 -carboxylic acid as polymerized units are added to the stock suspension before sheet formation. The low molecular weight copolymers which act as dispersants have virtually no effect on the efficiency of drainage aids and retention aids in papermaking, whereas low molecular weight homopolymers of acrylic acid have a very adverse effect on the efficiency of drainage aids and retention aids in papermaking.
The non-prior published German Application P 42 44 194.3 discloses water-soluble condensates which are obtainable by reacting ethyleneimine, polyetheramines and mixtures of the stated compounds with or nitriles of monoethylenically unsaturated carboxylic acids, chlorocarboxylic acids and/or glycidyl compounds of the formula ##STR1## where X is --NH.sub.2, --OMe or --OR, halohydrin, glycidyl, aziridine or isocyanate unit or a halogen atom as a functional group, solution at 20.degree. C., have a viscosity of at least 100 mPa.s.
The condensates are used as drainage aids, flocculents and retention aids in papermaking.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide pigment slurries which contain dispersants which do not adversely affect, or may even enhance, the efficiency of retention and drainage aids in the production of filler-containing papers.
We have found that this object is achieved, according to the invention, by aqueous paper slurries which contain up to 80% by weight of a finely divided pigment in dispersed form and from 0.1 to 5% by weight of at least one dispersant, if the dispersants used are reaction products which are obtainable by reacting ethyleneimine, polyetheramines and mixtures of the stated compounds with or nitriles of monoethylenically unsaturated carboxylic acids, chlorocarboxylic acids and/or glycidyl compounds of the formula ##STR2## where X is --NH.sub.2, --OMe or --OR, required, halohydrin, glycidyl, aziridine or isocyanate unit or a halogen atom as a functional group, solution at 20.degree. C., have a viscosity of at least 100 mPa.s.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The pigment slurries are prepared by milling pigments in the presence of the dispersants and water or dispersing finely divided pigments in water in the presence of the dispersants. The aqueous pigment slurries thus obtainable are used as additives to the paper stock in the production of filler-containing paper.
Suitable pigments are all pigments usually
REFERENCES:
patent: 3144380 (1964-08-01), Drennen
patent: 3252852 (1966-05-01), Lagally
patent: 4610801 (1986-09-01), Matthews et al.
patent: 4711727 (1987-12-01), Matthews et al.
patent: 4874466 (1989-10-01), Savino
patent: 5076846 (1991-12-01), Buri et al.
patent: 5244542 (1993-09-01), Bown et al.
patent: 5372747 (1994-12-01), Uhrig et al.
patent: 5384013 (1995-01-01), Husband et al.
Linhart Friedrich
Lorencak Primoz
Moench Dietmar
Reuther Wolfgang
Scherr Guenter
BASF - Aktiengesellschaft
Chin Peter
LandOfFree
Aqueous pigment slurries for production of filler-containing pap does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aqueous pigment slurries for production of filler-containing pap, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aqueous pigment slurries for production of filler-containing pap will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1528798