Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2002-07-23
2003-12-16
Gorr, Rachel (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C524S005000, C524S591000, C524S840000, C106S823000, C525S123000
Reexamination Certificate
active
06664360
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to alkoxylated acrylate and methacrylate macromonomers useful for preparing water-reducing additives for concrete, ultraviolet light (UV)-cured adhesives, and water-dispersed polyurethanes. The macromonomers are prepared using the continuous addition of starter in order to minimize the by-product formation during the alkoxylation reaction used to produce the macromonomer.
BACKGROUND OF THE INVENTION
Polyols produced using a double metal cyanide (DMC) catalyst are known to possess advantageous properties, such as low ethylenic unsaturation. Particularly preferred polyols made using these DMC catalysts are produced using a continuous addition of starter, together with optional initially charged starter, during the polymerization of epoxide to produce the desired polyol, as described in more detail in U.S. Pat. No. 5,777,177. The '177 patent teaches the use of water or a low molecular weight polyol as the starter, and discloses that the resulting polyol has a reduced amount of high molecular weight tail.
The continuous addition of other starters, such as hydroxypropylmethacrylate (HPMA) to initiate the polymerization of an epoxide, such as propylene oxide or ethylene oxide, in the presence of a DMC catalyst, is described in U.S. Pat. No. 5,854,386, notably at column 3, lines 13-16, and column 6, lines 15-18 thereof. The '386 patent discloses that this methodology is useful in preparing stabilizers for polymer polyols and impact modifiers made by reacting the stabilizer with one or more polymerizable vinyl monomers. This process is described in more detail in the paragraph bridging columns 7 and 8 of that patent. The '386 patent is incorporated herein by reference in its entirety.
Due to the hydrophobic nature of many polyurethanes, there is a need to employ a dispersion stabilizer when preparing water-dispersed polyurethanes in order to prevent the dispersion from “breaking” by virtue of precipitation or agglomeration of the polyurethane component. Conventional dispersion stabilizers for water-dispersed polyurethanes are typically expensive, and oftentimes do not perform as well as might be desired. For example, 2,2-dimethyol propionic acid (DMPA) is costly, in short supply, and typically does not provide acid groups in the desired location on the urethane molecule, namely in the middle of the hydrophobic polyether portion of the molecule, upon reaction with an isocyanate.
There currently is a need in the polyurethanes manufacturing community for inexpensive, homogeneous macromonomer compositions that are useful in preparing water-dispersed polyurethanes having alcohol water-dispersing moieties in a middle portion of the urethane molecules. The present invention provides one solution to this need by using “continuous addition of starter” (CAOS) methodology to prepare alkoxylated macromonomers, such as propoxylated acrylate- and propoxylated methacrylate- macromonomers. These macromonomers can be copolymerized with an acid, or combination of acids, to produce a stabilizer for water-dispersible polyurethanes. Alternatively, these macromonomers can be co-polymerized with a monomer, or combination of monomers, to produce copolymers that are useful as additives in concrete-forming compositions. These additives permit the use of a reduced amount of water in fabricating the concrete, and provide a further improvement over the water-reducing agents described in co-pending U.S. application Ser. No. 09/358,009 filed Jul. 21, 1999. These copolymers are also useful as additives in UV-curable adhesives in order to enhance the adhesive's performance.
SUMMARY OF THE INVENTION
One aspect of this invention provides an improved process for producing an alkoxylated acrylate macromonomer or an alkoxylated methacrylate macromonomer. The alkoxy moiety of the macromonomer contains between one and six carbons. In the process, a first component, namely a hydroxyalkylacrylate or a hydroxyalkylmethacrylate, is reacted with a second component, namely an alkylene oxide compound (preferably an alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof). The macromonomer is produced by co-feeding the reactants into the reaction vessel co-currently or counter-currently, and carrying out the reaction at a reaction temperature of between about 60° C. and about 130° C. in the presence of a DMC catalyst, and optionally in the presence of a solvent. The reaction employs a CAOS method whereby the first component is added to a reactor already containing at least some amount of the second component. Use of this CAOS method facilitates production of the desired macromonomer, and reduces the likelihood of forming unwanted byproducts.
In another aspect, the present invention comprises co-polymerizing the above-described macromonomer with a monomer selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, styrene, maleic acid, methyl methacrylate, and combinations thereof. The resulting copolymer is useful as a water-reducing additive for concrete formation. When this water-reducing additive is present in a reaction mixture comprising sand, cement, and water, less water is needed than the amount that is necessary to prepare concrete in the absence of the water-reducing additive.
In still another aspect, this macromonomer, and its derivatives, can be used as a performance-enhancing additive for a UV-curable adhesive.
In yet another aspect, the above-described macromonomer can be used in the preparation of water-dispersible polyurethanes. For this use, the macromonomer is co-polymerized with a monomer selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and combinations thereof, in order to produce a co-polymer containing hydroxyl and acid moieties. At least a portion of the hydroxyl moieties on the copolymer are then reacted with an isocyanate to provide the water dispersible polyurethane.
These and other aspects of the present invention will become apparent upon reading the following detailed description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
It has now been surprisingly found that macromonomers produced in accordance with the present invention using a continuous addition of starter methodology are particularly useful in fabricating water-reducing additives for concrete-forming compositions, in producing dispersants for water-dispersible polyurethanes and performance enhancing additives for UV curable compositions. Illustratively, the macromonomers are reacted with a vinyl monomer to produce a co-polymer that is useful as a water-reducing additive (WRA) in concrete-forming compositions.
The macromonomers are prepared at a relatively low reaction temperature (between about 60 degrees and about 130 degrees Centigrade, preferably between about 60° C. and about 110° C.) in the presence of a relatively low concentration of a DMC catalyst (5 ppm to 500 ppm, preferably 5 ppm to 50 ppm), optionally in the presence of a solvent. The relatively low concentration of DMC catalyst, together with the relatively low reaction temperature, has been found by the present inventor to reduce or minimize the homopolymerization of the acrylate and methacrylate reactants. These reaction parameters have also been found to reduce or minimize the trans-esterification of hydroxyalkyl methacrylate and hydroxyalkylacrylate to form unwanted di-methacrylate and di-acrylate by-products. These byproducts are undesirable since they would be detrimental to the present inventor's envisioned use of the macromonomers as intermediates in the production of dispersants for water-dispersed polyurethanes, as well as the other uses described herein.
The macromonomers produced in accordance with the present invention are made using CAOS methodology wherein the methacrylate or acrylate “starter” is continuously added during the course of the reaction. The alkylene oxide compound employed in oxyalkylating the “starter” or “initiator” may
Arco Chemical Technology L.P.
Gorr Rachel
Wiggin & Dana
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