Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2002-07-16
2004-05-18
Green, Anthony J. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S413000, C106S447000, C106S448000, C106S453000, C106S459000, C106S460000, C106S473000, C106S474000, C106S493000, C106S495000, C106S496000, C106S497000, C106S498000, C106S503000
Reexamination Certificate
active
06736892
ABSTRACT:
FIELD OF INVENTION
The present invention pertains to a process of preparing an aqueous dispersion containing a pigment uniformly distributed throughout. In particular, the invention relates to a process of dispersing a pigment in an aqueous system with a styrenated and sulfated phenol ethoxylates. The invention is also directed to aqueous carbon black dispersions containing carbon black and surfactants based on sulfated styrenated phenol alkoxylates, in addition to water. The dispersions are produced by dispersing the carbon black and the other constituents in water, using bead mills, ultrasonic mills and/or an ultra-turrax. The aqueous carbon black dispersions can be used in many applications such as printing inks including ink-jet inks or writing inks. Also the carbon black dispersions are also useful in lubricating applications.
The present invention also relates to pigment dispersions free from organic solvents and containing a carboxymethylated styrenated phenol alkoxylate as dispersing agent. The pigment dispersion can be used in paints based on water as well as organic solvents.
The present invention also provides homogeneous pigment dispersions which are completely free from organic solvents and which, without causing flocculations which may cause unacceptable differences in color, may be used in water-based paints as well as paints containing organic solvents.
This invention also relates to pigment dispersions suitable for pigmenting hydrophilic as well as hydrophobic media. The present invention further relates to methods of preparing inorganic pigment dispersions useful in the manufacture of latex paints, and latex paints prepared therewith.
BACKGROUND OF THE INVENTION
One of the most difficult pigments to disperse and stabilize in a waterborne coating formulations or rubber compositions is carbon black, because of its enormous surface area and high oil absorption. Additionally, especially where a conductive carbon black pigment is to be utilized, it is important that the reduction of the electrostatic properties be minimized, and that the other physical characteristics of the final coating are not deleteriously affected by the particular pigment dispersant employed.
The products commonly employed in the prior art as carbon black dispersants in coatings are salts of an acrylic acid copolymer, acetylenic diol surfactants, or polyalcohol ethers which fit into various classes of wetting and dispersing agents, (Calbo, Handbook of Coatings Additives, Dekker pg. 516). Such additives could be called on to function as more than a dispersant and can also act in one or more of the following ways: a) to prevent flocculation, b) to prevent hard settling, c) to improve jetness/color/gloss, d) to control viscosity, and/or e) to improve wetting of the base resin.
Various considerations are important in determining the usefulness of any additive as a dispersing agent for use with a carbon black or with other pigments, depending upon the product into which such a dispersion is to be incorporated. When used throughout this application the terms pigment(s) or pigment dispersion(s) are intended to encompass various materials which may be intended to impart either color and/or serve some other function, such as for example the use of carbon black in rubber where, in addition to adding color, such also acts as a reinforcing agent.
One of the most important considerations in determining whether a particular dispersant will be useful for use with a given pigment or pigments when such a pigment is to be used in a paint or coating composition is whether such a dispersant/pigment combination will or will not impart a conductive nature or characteristic to the dried paint film or coating into which it has been added.
The automotive industry is replacing and will continue to replace exterior metal body panels on vehicles with plastic and composite body panels. Some reasons for this change are weight reduction, flexibility of design, and lower tooling costs. The replacement of metal body panels by plastics and composites is not without difficulties.
One problem of note is the electrostatic spray painting of plastics. Electrostatic spray painting is the preferred manner of applying automotive topcoats. Spray painting normally gives the best appearance to the vehicle and the electrostatic technique assures the most economical use of the material. The problem arises because plastics do not paint well electrostatically unless a conductive primer is used.
Amongst the most important considerations for determining the utility of any dispersant to be used in conjunction with conductive carbon blacks are the following: the inherent rheological stability of the dispersion, both alone and when added to a formulated paint; resistance to flocculation of the carbon black/dispersant mixture and in the final paint or coating; and ability to achieve low viscosity at high pigment loadings.
The various prior art references of which the applicants are aware which relate to dispersing agents for pigment additives, such as carbon blacks, suffer from a number of shortcomings. The most significant shortcomings of the carbon black dispersants of the prior art, including those used for conductive carbon blacks, are: high levels of dispersant may be required which tends to detrimentally affect the physical properties of formulated paints, such as adversely affecting the resultant humidity resistance, yellowing upon exposure to UV light, loss of cure in melamine cross-linked systems, and other undesirable effects; inability to prevent reflocculation of carbon black, resulting in the loss of electrical conductivity in dried paint films; and incompatibility of the dispersant with the particular resin system selected for use in the final paint formulation.
Additionally, more and more paints are produced which are water-based and completely free from organic solvents, such as glycol ethers. When toning these paints to the desired colour, use is made to a great extent of pigment dispersions, which can be used both for water-based paint and for paint based on organic solvents. The pigment dispersions are normally composed of pigments, fillers, dispersing agents and an aqueous phase in the form of ethylene glycol, di- and triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and glycerol. In most cases, the dispersing agent is a nonionic surface-active compound or a combination of nonionic and anionic surfactants. For environmental reasons, it is however desirable that the pigment dispersions are solvent-free.
The shortcomings of the prior art dispersing agents noted above may be overcome by employing certain sulfated and/or carboxymethylated styrenated phenol alkoxylates in accordance with the present invention.
OBJECTS OF THE INVENTION
It is a first object of the present invention to provide novel pigment dispersions incorporating novel surfactants.
It is another object of the instant invention to provide novel pigment dispersions containing surfactants based on sulfated styrenated phenol alkoxylates.
A further object of the invention is to provide novel carbon black dispersions containing novel surfactants.
A still further object of the invention is to provide novel carbon black dispersions incorporating sulfated styrenated phenol alkoxylates.
An additional object of the invention is to provide novel pigment dispersions incorporating sulfated styrenated phenol ethoxylates.
A still further object of the invention is to provide carbon black dispersions containing surfactants based on sulfated styrenated phenol ethoxylates.
An additional object of the present invention is sulfated styrenated phenol alkoxylates.
Another main object of the present invention is to provide pigment dispersions incorporating sulfated styrenated phenol ethoxylate/propoxylate surfactants.
Another object of the present invention is to provide carbon black dispersions incorporating sulfated styrenated phenol ethoxylate/propoxylate surfactants.
A still further object of the present invention is to provide graphite dispersions incorp
Godwin Edward R.
Weipert Paul David
Angres Isaac A.
Ethox Chemicals LLC
Green Anthony J.
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