Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-07-02
2002-03-12
Wilson, Donald R. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S330100, C525S384000, C526S317100, C526S318100, C526S318300, C526S271000, C523S340000, C523S343000
Reexamination Certificate
active
06355727
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a bulk polymerization and esterification process for maximizing the conversion of an aliphatic alkanol to an ester in a radically-initiated polymerization of an ethylenically unsaturated acid-functional monomer, to the polymeric products produced by the process, to polymeric products, to processes for preparing emulsions and dispersions utilizing the polymeric products, and to overprint varnishes (OPVs), inks, coatings, surfactants, adhesives, paints, primers, and floor polishes containing the polymeric products.
BACKGROUND OF THE INVENTION
Conventional solvent-based industrial finishes and coatings have presented many problems to date. Organic solvents can pollute the workplace and environment. In addition, many organic solvents are readily ignited, toxic, expensive, and lower the quality of finishes, and they can add undesirable colors to an otherwise colorless finish. As a replacement for these solvent-based finishes, the trend in the polymer industry has been toward high solids, liquid coatings and polymerization processes reducing or eliminating solvent.
High solids coatings offer significant advantages over conventional, solvent-thinned coatings. For example, high solids coatings do not pollute the air, they reduce or eliminate exudation of fumes in use, they reduce the energy requirements for their preparation in terms of material, energy expended and labor, and unlike solvent-based systems, they do not present significant fire and toxicity problems. High solids coatings also provide substantial advantages over other high solids liquids, such as solventless, water-borne, powder and non-aqueous systems. Additionally, they offer a better balance of properties.
One of the most enduring and difficult problems in preparing and utilizing high solids coatings is the selection and control of viscosity. Significant efforts have been made to improve processes and polymeric products for use in high solids applications. For example, various methods of characterizing polymers such as the number average molecular weight (M
n
), weight average molecular weight (M
w
), and the sedimentation average molecular weight (M
z
) and ratios calculated using these characteristics such as the polydispersity ratio (M
w
/M
n
) and the dispersion index (M
z
/M
n
) have been investigated and adjusted to obtain polymeric products with viscosities useful for high solids applications. Although these efforts have produced vast improvements in polymers for use in high solids applications, improved processes are required to produce polymers with characteristics maximized for high solids applications.
U.S. Pat. No. 4,414,370 discloses a continuous bulk polymerization process for polymerizing vinylic monomers to prepare low molecular weight polymers employing thermal initiation at reaction temperatures from 235° C. to 310° C. and residence times of at least 2 minutes in a continuous stirred reactor zone. The vinylic monomers of the disclosed process include styrenic monomers such as styrene and &agr;-methylstyrene; acrylic monomers such as acrylic acid, methacrylic acid, acrylates, methacrylates; and other non-acrylic ethylenic monomers such as vinyl acetate.
U.S. Pat. No. 4,529,787 discloses a continuous bulk polymerization process including an initiator for preparing low molecular weight, uniform polymers from vinylic monomers at short residence times and moderate reaction temperatures to provide high yields of a product suitable for high solids applications. The disclosed vinyl monomers include styrenic monomers such as styrene and &agr;-methylstyrene; acrylic monomers such as acrylic acid, methacrylic acid, acrylates, methacrylates, and functional acrylic monomers; and non-acrylic ethylenic monomers such as maleic anhydride and vinyl pyrrolidone.
U.S. Pat. No. 4,546,160 discloses a continuous bulk polymerization process for polymerizing acrylic monomers to prepare low molecular weight, uniform, polymers for use in high solids applications which uses a minor amount of initiator at short residence times and moderate temperatures.
U.S. Pat. No. 5,130,369 discloses a batch process for preparing functionalized polymeric compositions. The functionalized polymeric compositions are prepared by polymerizing an ethylenically unsaturated functional monomer in a solvent including a reactive compound. The polymeric compositions prepared according to the process can be used as builders in detergent compositions, as pigments, dispersants in coating compositions, as tanning agents for leather, as associative thickeners and as rheology modifiers in coating compositions.
U.S. Pat. No. 5,521,267 discloses a batch process for preparing polymers from ethylenically unsaturated compounds containing acid groups with further ethylenically unsaturated compounds and monohydroxy compounds The polymer industry has long known that continuous polymerization processes are best for obtaining large quantities of polymeric product. Furthermore, optimized continuous processes provide economic advantages over batch polymerization processes and may provide more uniform polymeric products. While continuous processes have been disclosed for the preparation of certain polymeric products for use in high solids coatings applications, a continuous process is needed for preparing polymeric products with improved viscosity characteristics in aqueous media for use in high solids applications. Furthermore, a need remains for a polymerization process which incorporates an esterification reaction in which an alcohol with desirable viscosity-modifying behavior is incorporated into a polymeric chain with a high degree of conversion.
SUMMARY OF THE INVENTION
It would be highly desirable to be able to produce a polymeric product exhibiting low viscosity in aqueous solution using a continuous polymerization process where an alkanol is incorporated with high conversion into the polymer via an esterification reaction with an ethylenically unsaturated acid-functional monomer or a residue of such a monomer already present in the polymer.
One object of the invention is to provide a continuous bulk polymerization and esterification process including charging continuously into a reaction zone at least one ethylenically unsaturated acid-functional monomer and at least one alkanol having the formula ROH, where R is a linear or branched chain alkyl moiety, or combinations thereof, having greater than 11 carbon atoms. The process also includes maintaining a flow rate through the reaction zone sufficient to provide an average residence time of the monomers in the reaction zone of less than 60 minutes and maintaining a temperature in the reaction zone sufficient to produce a polymeric product. Preferably, the polymeric product of the continuous bulk polymerization and esterification process incorporates at least 80 percent of the alkanol as an ester of the ethylenically unsaturated acid-functional monomer when the alkanol is present in the reaction zone in an average amount of at least up to 25 mole percent of the total moles of the ethylenically unsaturated monomers. More preferably, the polymeric product of the continuous bulk polymerization and esterification process incorporates at least 85 percent of the alkanol as an ester of the ethylenically unsaturated acid-functional monomer when the alkanol is present in the reaction zone in an average amount of at least up to 20 mole percent of the total moles of the ethylenically unsaturated monomers. Most preferably, the polymeric product of the continuous bulk polymerization and esterification process incorporates at least 90 percent of the alkanol as an ester of the ethylenically unsaturated acid-functional monomer when the alkanol is present in the reaction zone in an average amount of at least up to 15 mole percent of the total moles of the ethylenically unsaturated monomers.
In preferred processes, the ethylenically unsaturated acid-functional monomer is acrylic acid, methacrylic acid, or crotonic acid while in other preferred processes, the R group of the alkan
Andrist Kevin M.
Blasko John E.
Calhoun Glenn C.
Hansen Frederick C.
Hellwig Dean R.
Bovee Warren R.
Hamilton Neil E.
Rymarz Renee J.
S. C. Johnson Commercial Markets, Inc.
Wilson Donald R.
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