Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-03-15
2001-05-29
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
Reexamination Certificate
active
06239201
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aqueous dispersions containing fillers and/or pigments and novel dispersing agent mixtures.
2. Description of the Prior Art
Aqueous dispersions of fillers and/or pigments, which can be used, for example, as pigment pastes in coating compositions for buildings, generally have a solids content of 30 to 90 wt. %. The dispersing agent should impart suitable rheological properties to the dispersion at the desired solids content and, in the case of pigment pastes, the property of being readily incorporated into corresponding coatings and paints. The dispersing agent or wetting agent should also improve the wetting of the materials to be dispersed or wetted, facilitate deagglomeration during the dispersion process and stabilize the finished dispersion against agglomeration, sedimentation and flooding.
Organic and inorganic dispersing agents for these purposes are known. Phosphates, polyphosphates or sodium hexametaphosphate are used as inorganic dispersing agents.
Organic dispersing agents include polymers and copolymers of methacrylic and acrylic acid having a low to average molecular weight. DE-A 2,700,444 describes the use of copolymers of maleic acid derivatives; JP-A 57/095 396 describes the use of copolymers of acrylic acid and of styrenesulfonic acid; JP-A 56/115630 describes the use of copolymers of unsaturated sulfonic acids; and DE-OS 3,101,939 describes the use of phosphorus-containing polyacrylic acid copolymers. The use of sulfonated polyester resins is described in SU-A 861,377 and the use of derivatives of styrene-maleic anhydride copolymers is disclosed in SU-A 903,438. The use of low molecular weight non-ionic surfactants is described in BE-A 741,374.
The effectiveness of the known dispersing agents is in many cases not adequate to obtain pigment pastes and/or dispersions having optimal properties for technical use. If the viscosity of such pigment pastes and/or dispersions is too high, the solids content has to be decreased in order to obtain technically usable dispersions, for example, coating compositions to be applied by brushing. This leads, however, to deterioration in the quality of these paints, in particular their strength of color, covering power and/or film formation.
In the case of pigment pastes, a non-optimal dispersion process leads to deterioration of the stability of the pastes and of the paints and coatings produced therefrom. The depth of color of the resulting coatings is also not optimal.
Accordingly, it is an object of the present invention to provide new dispersing and wetting agents for the preparation of pigment and/or filler pastes having improved properties.
This object may be achieved with the aqueous compositions according to the invention, which are described hereinafter.
SUMMARY OF THE INVENTION
The present invention relates to an aqueous dispersion containing a pigment and/or a filler and, as dispersing agent,
A) 50 to 90 wt. % of a non-ionic alkylene oxide adduct having a number average molecular weight of 2000 to 100,000,
B) 0 to 40 wt. % of a salt of a polycarboxyl compound,
C) 5 to 40 wt. % of a salt of an acidic (poly)phosphate ester and
D) 0 to 60 wt. % of a water-soluble or water-dispersible polyurethane oligomer,
wherein the sum of the components A)+B)+C)+D) equals 100 wt. %, based on the weight of A), B), C) and D), and the amount of at least one of components B) or D) is not 0.
DETAILED DESCRIPTION OF THE INVENTION
Component A) is present in a quantity of 50 to 90 wt. %, preferably 60 to 80 wt. %. Component C) is present in a quantity of 5 to 40 wt. %, preferably 10 to 40 wt. % and more preferably 10 to 30 wt. %. Components B) and D) are present, preferably independently of one another, each in a quantity of preferably 0 to 40 wt. % and more preferably 20 to 40 wt. %.
Mono-, di- and polyfunctional species are suitable for use as non-ionic alkylene oxide adducts A). Examples include condensation products of alkylene oxides with any compounds containing active hydrogen. The alkylene oxides contain 2 to 20 carbon atoms, preferably 2 or 3 carbon atoms. The compounds containing active hydrogen include mono-, di- or polyfunctional, optionally substituted phenols, alcohols, thioalcohols or amines. Condensation products of alkylene oxides with &agr;,&ohgr;-aminopolyethers are also suitable, e.g., those having number average molecular weights of 200 to 100,000, preferably of 500 to 60,000.
A particularly preferred group of compounds suitable for use as component A) corresponds to formula (I)
wherein
R
1
represents an aliphatic, aromatic or araliphatic group having 1 to 40 carbon atoms,
R
2
represents hydrogen, phenyl or an alkyl group having 1 to 12 carbon atoms and
n has a value of 1 to 200, preferably 4 to 100 and more preferably 6 to 30.
Suitable components A) are described in DE-A 3,815,299.
Examples of compounds suitable for use as component B) are homopolymers and copolymers of methacrylic and/or acrylic acid and salts thereof. Preferred are those which have a number average molecular weight of 800 to 40,000, more preferably 1000 to 20,000, and are present in the form of their sodium salts, potassium salts or ammonium salts. Other oligomers containing carboxyl groups, such as salts of polyaspartic acid or homo or copolymers thereof having number average molecular weights of 200 to 30,000, are also suitable. Low molecular weight carboxylates, such as salts of phosphonobutanetricarboxylic acids or iminosuccinic acids, are particularly suitable.
Known salts of phosphoric and polyphosphoric acid are suitable for use as component C). Salts of di- and monoalkylphosphates with organic amines such as dimethylethanolamine, methyldiethanolamine, triethanolamine or dimethylaminocyclohexane are particularly preferred.
Known water-soluble or water-dispersible oligourethanes are suitable as component D). Examples include the reaction products of polyisocyanates with hydrophilic polyethers and optionally a tertiary amino compound. The presence of component D) provides an improvement in the dispersions according to the invention if they are prepared from pigments or fillers which are not readily dispersible, such as carbon black, quinacridone or phthalocyanines.
The aqueous dispersions according to the invention contain the combination of dispersing agents in quantities of 0.02 to 200 wt. %, preferably 0.05 to 100 wt. % and more preferably 0.5 to 80 wt. %, based on the remainder of the solids present in the dispersion, i.e., the solids content of the dispersion excluding the dispersing agent.
The dispersions of pigment pastes or filler pastes containing the combinations of dispersing agents according to the invention are distinguished by having improved flow properties, especially when compared to dispersions that contain only one dispersing agent.
Components C) and D) may be selected according to known methods, for example, on the basis of viscosity measurements made on the dispersions or on pigment pastes. Combinations of components A)+C)+B) and/or D) are particularly preferred. The ratio to one another of the components A) to D) can be varied in different filler and/or pigment compositions. The effectiveness of combinations of dispersing agents according to the invention may optionally be optimized by varying the proportions of the individual components to one another, in order to obtain dispersions or pigment pastes having the best possible flow properties. The respective optimal ratio of components can be easily determined by screening tests.
Any organic and inorganic solids are suitable for use as fillers and pigments. Examples include organic pigments such as phthalocyanines, benzidines, arylamide yellow, nickel azo yellow, diarylidones, isoindolines, perylene red, thioindigo red, quinacridone violet and carbon black; inorganic pigments such as titanium dioxide, iron oxides, zinc oxides, chromates, molybdates and cobalt spinels; and fillers such as silicates, aluminum titanates, silicon nitrites, barium sulfate and calcium
Edelmann Dirk
Link Gunter
Mazanek Jan
Bayer Aktiengesellschaft
Gil Joseph C.
Michl Paul R.
Roy Thomas W.
LandOfFree
Aqueous pigment and/or filler dispersions containing a... 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 and/or filler dispersions containing a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aqueous pigment and/or filler dispersions containing a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2567520