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
2002-06-20
2004-02-03
Niland, Patrick D. (Department: 1714)
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...
C524S589000, C524S590000, C528S085000
Reexamination Certificate
active
06686435
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for making natural oil-based polyols. Still further, the present invention includes using natural oil-based polyols to produce polyurethane resins for use as casting compounds for electrical applications.
Polyols may be produced from petroleum. However, there has been an active trend in recent years to use renewable resources, such as vegetable and animal oils. Vegetable and animal oil molecules must be chemically transformed in order to introduce hydroxyl groups. For instance, soybean oil does not contain any hydroxyl groups but has on average about 4.6 double bonds per molecule. The unsaturated portions of the vegetable or animal oil molecule can be converted to hydroxyl groups. However, many reactions for preparing polyols from various natural oils are not very selective. By-products, in addition to alcohol groups, are created during the transformation. Furthermore, many conventional methods of preparing polyols from natural oils do not produce polyols having a significant content of hydroxyl groups. Still further, many available methods of preparing polyols from natural oils do not produce products having a desirable viscosity. Greases or waxes often result as a consequence of such chemical transformations.
Conventionally, cast electrical components such as dry voltage transformers and insulators are formed from epoxy resins. Epoxy resins are rather expensive to use. Still further, epoxy resins are not easy to handle at low temperatures and have poor elasticity. Polyurethane resins prepared with castor oil have also been produced. However, these resins tend to be rubbery and thus undesirable for certain casting applications. Still further, castor oil-based polyurethanes have some limitations due to their higher price and environmental problems related to their by-products.
In order to overcome the deficiencies found with conventional processes for making natural oil-based polyols, a method for making natural oil-based polyols from vegetable or animal oil or epoxidized vegetable or animal oil is needed for a variety of applications including preparation of, through polyurethane chemistry, a resin for use as an electroinsulating casting compound, which is another embodiment of the present invention. Still further, this method of making natural oil-based polyols should avoid substantial side reactions, such as esterification, cyclization, polymerization, crosslinking, and other undesirable reactions, and should produce polyols having a high hydroxyl content and a desirable viscosity.
SUMMARY OF THE INVENTION
According to the present invention, a method for making natural oil-based polyols directly from vegetable or animal oil using a consecutive two-step process involving epoxidation and hydroxylation is provided. Specifically, this process comprises adding a peroxyacid to a natural oil wherein said natural oil and said peroxyacid react to form an epoxidized natural oil and adding said epoxidized natural oil to a mixture of an alcohol, water, and a fluoboric acid catalyst. The catalytic amount of fluoboric acid is less than about 0.5% by weight of the entire reaction mixture, and the amount of water is about 10 to 30% by weight of the entire mixture. The epoxidized natural oil undergoes hydroxylation and forms a natural oil-based polyol. The present invention further includes a method for making natural oil-based polyols from epoxidized oil by hydroylating the epoxidized oil in the presence of fluoboric acid, alcohol and water in the amounts discussed above.
The natural oil-based polyols created by this method may be reacted with isocyanates so as to form polyurethanes, which is another embodiment of the present invention. Alternatively, fillers such as silica may be combined with these natural oil-based polyols before they are reacted with isocyanates to form polyurethanes. In still another embodiment of the present invention, polyurethanes made from natural oil-based polyols may be used to form electroinsulating casting resins for use in electrical applications.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The method of the present invention involves making natural oil-based polyols by converting each of the double bonds of the natural oil molecule into a hydroxyl group. This method takes place at approximately atmospheric pressure.
The process of the present invention involves epoxidation and subsequent hydroxylation of a natural oil so as to make a polyol. More specifically, the process of the present invention includes adding a peroxyacid in a solvent to a vegetable or animal oil wherein the oil and the peroxyacid react to form an epoxidized oil, and adding said epoxidized oil, which is in the solvent, to a mixture of an alcohol, water, and a catalytic amount of fluoboric acid so as to form a natural oil-based polyol. These are consecutive, non-stop steps. The reaction is not stopped after the epoxidized natural oil forms so as to purify the intermediate product.
Another embodiment of the present invention is a method of making polyols from epoxidized natural oil by the second step of the process outlined above. This second step provides a fast conversion of an epoxidized oil to a polyol. Epoxidized natural oils, the starting component of this second step, can be obtained from Ferro Corporation, C. P. Hall, Ashland Chemicals or Union Carbide or made from natural oil, as discussed above. Preferably, the epoxidized natural oil used in the method of the present invention has an epoxide content between 6-7% by mole epoxy groups per mole of epoxidized natural oil, and it has about 90 to 95% of the double bonds in the natural oil epoxidized. In other terms, preferably, each epoxidized natural oil molecule has about 2-6 epoxy groups. In still other terms, preferably, the epoxidized natural oil used has an epoxide content of 2-8 weight %.
Any vegetable or animal oil may be used in this process. Examples of vegetable and animal oils that may be used include, but are not limited to, soybean oil, safflower oil, linseed oil, corn oil, sunflower oil, olive oil, canola oil, sesame oil, cottonseed oil, palm oil, rapeseed oil, tung oil, fish oil, or a blend of any of these oils. Alternatively, any partially hydrogenated or epoxidized natural oil or genetically modified natural oil can be used to obtain the desired hydroxyl content. Examples of such oils include, but are not limited to, high oleic safflower oil, high oleic soybean oil, high oleic peanut oil, high oleic sunflower oil (NuSun sunflower oil) and high erucic rapeseed oil (Crumbe oil). The iodine values of these natural oils range from about 40 to 220 and more preferably from about 80 to 180. When natural oils having lower iodine values are used to make natural oil-based polyols, polyols with lower hydroxyl numbers and thus lower viscosities are created.
Any peroxyacid may be used in the epoxidation reaction. Examples of peroxyacids that may be used include, but are not limited to, peroxyformic acid, peroxyacetic acid, trifluoroperoxyacetic acid, benzyloxyperoxyfornic acid, 3,5-dinitroperoxybenzoic acid, m-chloroperoxybenzoic acid, or any combination of these peroxyacids. The peroxyacids may be formed in-situ by reacting a hydroperoxide with the corresponding acid, such as formic or acetic acid. Examples of hydroperoxides that may be used include, but are not limited to, hydrogen peroxide, tert-butylhydroperoxide, triphenylsilylhydroperoxide, cumylhydroperoxide, or any combination of these hydroperoxides. Preferably, the peroxyacid is in a solvent such as acetic acid, formic acid, or chloroform.
Fluoboric acid is us
Guo Andrew
Javni Ivan
Petrovic Zoran
Zhang Wei
Niland Patrick D.
Pittsburg State University
Stinson Morrison & Hecker LLP
LandOfFree
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