Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-02-13
2001-03-13
Woodward, Ana (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S558000
Reexamination Certificate
active
06201048
ABSTRACT:
FIELD OF THE INVENTION
This invention belongs to the field of emulsion chemistry. In particular, it relates to stable waterborne polymer compositions useful in a variety of coating formulations.
BACKGROUND OF THE INVENTION
In an increasing number of industries, aqueous coating compositions continue to replace traditional organic solvent-based coating compositions. Paints, inks, sealants, and adhesives, for example, previously formulated with organic solvents are now formulated as aqueous compositions. This reduces potentially harmful exposure to volatile organic compounds (VOC's) commonly found in solvent-based compositions. While the move from organic solvent-based to aqueous compositions brings health and safety benefits, the aqueous coating compositions must meet or exceed the performance standards expected from solvent-based compositions. The need to meet or exceed such performance standards places a premium on the characteristics and properties of waterborne polymer compositions used in aqueous coating compositions.
Waterborne polymer having various functional groups have been used to impart and achieve desired properties to a particular coating composition. For example, a coating composition should exhibit good film formation, print and block resistance, as well as adhesion and tensile properties. Polymers having acetoacetoxy- and enamine-functional groups represent one example of waterborne polymers which have such properties, may carry different functional groups, and are useful in aqueous coating compositions.
U.S. Pat. No. 5,296,530 discloses a quick-curing coating prepared from a polymer having acetoacetyl groups, in which substantially all of the acetoacetyl groups have been converted to enamine functional groups. This conversion occurs, for example, by treatment with ammonia or a primary amine. Coatings so prepared cure more quickly under sunlight or ultraviolet light than coatings which contain the acetoacetyl functional polymer but which have not been converted to an enamine form.
U.S. Pat. Nos. 5,484,975 and 5,525,662 describe the preparation of polymers containing functional acetoacetate groups and then, following the polymerization, reacting the acetoacetate group with a functional amine to form an enamine. The resulting polymers are reported to have a variety of uses including coatings, sealants, adhesives, and saturant applications.
U.S. Pat. No. 5,498,659 discloses polymeric formulations comprising an aqueous carrier, at least one polymeric ingredient, a non-polymeric polyfunctional amine, and a base. The polymeric ingredient has both acid-functional and acetoacetoxy-type functional moieties. The aqueous polymeric formulations produce crosslinked polymeric surface coatings on a substrate.
Japanese Pat. No. 61-21171 describes a fast-curing adhesive of two separate liquids. The first liquid is an aqueous solution and/or aqueous emulsion of a polymer compound containing an acetoacetyl group. The second liquid consists of polyethylenimine.
Even with current waterborne polymer formulations, a need remains for improved aqueous coating compositions and waterborne polymers for use in those compositions. In particular, a need exists for waterborne polymer compositions which may formulate as a single, stable composition but which undergo crosslinking upon film formation imparting one or more desired properties to the resulting coating. The present invention meets such needs.
SUMMARY OF THE INVENTION
This invention provides stable waterborne polymer compositions which are stabilized against gelling upon addition of a poly(alkylenimine), preferably by post polymerization addition of certain anionic surfactants. These stable waterborne polymer compositions are useful in a variety of coating formulations such as, for example, paints, inks, sealants, and adhesives. When used in coating formulations, the stable waterborne polymer compositions of the invention provide adhesion and crosslinking in the final film or coating. The film or coating may be cured at ambient temperatures or may be thermally cured. Methods of preparing stable waterborne polymer compositions are also disclosed, along with methods of stabilizing latex compositions against gelling upon addition of a poly(alkylenimine).
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides stable waterborne polymer compositions, that is compositions containing a polymer and water. Waterborne polymer compositions include, but are not limited to, latexes, dispersions, microemulsions, or suspensions. Waterborne polymer compositions of the present invention are stable and may be stored at room temperature or moderately above room temperature (e.g., about 50 to 60° C.) and provide adhesion and crosslinking upon film formation when applied to a substrate. Yet, a film or coating formed with polymers of the invention may be cured at room temperature (ambient cure) or at elevated temperatures (thermal cure).
The polymers used to prepare the waterborne polymer composition of the present invention are generally prepared as particles. The particles may be structured or unstructured. Structured particles include, but are not limited to, core/shell particles and gradient particles. The average polymer particle size may range from about 25 to about 600 nm.
The polymer particles generally have a spherical shape. In one embodiment, the generally spherical polymeric particle may have a core portion and a shell portion. The core/shell polymer particles may also be prepared in a multilobe form, a peanut shell, an acorn form, or a raspberry form. It is further preferred in such particles that the core portion comprises about 20 to about 80 of the total weight of said particle and the shell portion comprises about 80 to about 20 of the total weight volume of the particle.
Although the following description will be directed to a discussion of specific types of polymers, other waterborne latex polymers that are susceptible to gelling upon addition of a poly(alkylenimine) are within the scope of the present invention.
Enamine-functional polymers represent a preferred embodiment of polymers used to form the stable waterborne polymer compositions of the present invention. Enamine-functional polymers may be prepared by reacting a polymer having acetoacetoxy groups with ammonia or a primary or secondary amine. The primary or secondary amine may be a monoamine compound or a polyamine compound. Preferred amines include, for example, triaminononane, H
2
N(CH
2
)
3
CH(CH
2
NH
2
)(CH
2
)
4
NH
2
(CAS Registry No. 1572-55-0), available from Monsanto; 2-amino-2-methyl-1-propanol available as AMP-95 product from Angus Chemical Company, Buffalo Grove, Ill.; or, as described below, polyethylenimine, (PEI). In water-based latexes, the enamine functionality serves to further stabilize the acetoacetoxy-groups and protect them from hydrolysis. Enamine-functional polymers have been described in Moszner et al., Polymer Bulletin 32, 419-426 (1994); European patent Application No. 0 492 847 A2; U.S. Pat. No. 5,296,530; and U.S. Pat. No. 5,484,849. These documents are incorporated herein by reference.
Acetoacetoxy-type functional polymers useable in the present invention may be prepared by free radical emulsion polymerization of vinyl monomers having an acetoacetoxy functionality such as those of Formula (I) below with other vinyl monomers. This combination of monomers provides water-based dispersion of polymer particles where the polymer has pendant acetoacetoxy groups. As used here, a “vinyl” monomer is an ethylenically unsaturated monomer. A pendant acetoacetoxy group is not strictly limited to those at the termini of the polymer. Pendant acetoacetoxy groups also include groups attached to the polymer's backbone and available for further reaction.
Acetoacetoxy-type functional polymers preferably contain about 0.5 to about 30 weight percent of vinyl monomers having acetoacetoxy-type functionality such as those of Formula I, and about 99.5 to about 70 weight percent of other vinyl monomers, preferably alkyl (meth)acrylates having 1 to 18 ca
Raynolds Peter Webb
Scott Duane Allan
Allen Rose M.
Eastman Chemical Company
Gwinnell Harry J.
Woodward Ana
LandOfFree
Stable waterborne polymer compositions containing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stable waterborne polymer compositions containing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stable waterborne polymer compositions containing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436595