Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-05-19
2001-03-13
Medley, Margaret (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S306000, C524S310000, C524S312000, C524S313000, C508S491000, C508S493000
Reexamination Certificate
active
06201053
ABSTRACT:
BACKGROUND OF THE INVENTION
Triglycerides occur as normal constituents of all forms of animal, vegetable and marine life. The fats of sea life are characterized by the presence of high molecular weight, highly unsaturated acids associated with only minor amounts of saturated acids. In contrast, the fats of land animals contain large amounts of C
16
and C
18
saturated and unsaturated acids, whereas fats of vegetable origin contain substantial amounts of closely related acids which are characteristic of a particular source.
Our ancestors developed many specific uses for fats in addition to their use as foods. It is believed that saponification was the first chemical reaction to which oils and fats were subjected, and the early chemical history of these substances actually constitutes a study of this process. The products of saponification offered the initial clue to the actual structure of the fats. Soaps were first prepared by boiling fats with wood ashes and were considered to be a combination of the fats with the ash constituents. Later, caustic was substitued for the wood ashes. The first United States patent was issued in 1790 to Samuel Hopkins, as signed by George Washington, and it covered the making of pearl-ash as an ingredient of soap manufacture.
It is necessary to go far back into chemical history in order to retrace the various contributions which have culminated in our present ideas concerning fats and saponification. More recently, however, improvements in partial saponification of fats were made. For example, when mixtures of salts of fatty acids and esters of fatty acids are produced by partial saponification, there is a tendency of the salts (soaps) to separate into curds. U.S. Pat. No. 4,824,583 issued in 1989 and it concerns the problem of incompatibility of soaps and esters produced during partial saponification. In order to produce soaps and esters as a homogeneous composition, oxidized polyethylene was used during partial saponification. It was believed that the oxidized polyethylene, particularly the functional carboxyl groups, reacted with components of the saponification mixture to form esters which were believed to promote homogeneity of the composition. Furthermore, in this '583 patent, the partially saponified triglycerides resulting from the reaction with oxidized polyethylene were used as lubricants in rigid PVC compositions.
In brief, hydrolysis of triglycerides with alkaline or alkaline earth metal bases is ancient. The reaction produces glycerol and a mixture of metal salts when one hundred percent of the saponification of the starting triglyceride is achieved. When saponification is less than one hundred percent, mono-substituted and di-substituted glycerides are obtained with triglycerides. However, there has been very little activity as represented by the above '583 patent for the use of partial saponification products as polymer additives. This may be in part attributable to the evolution of the metallic stearate and glyceryl ester industries because both of these industries predate polymers and plastics industries. In the continuing search for more cost-effective solutions in non-polymer areas, high-purity stearate products evolved first. By the time polymer applications became commercial opportunities, additives manufacturers had production facilities dedicated to making high-purity products.
Against this background, this invention is directed to improvements in partially saponified triglycerides, their methods of manufacture, applications as polymer additives, and use in other areas.
SUMMARY OF THE INVENTION
This invention relates to homogeneous partially saponified triglycerides (PSTs) which consist essentially of a metal salt of a fatty acid (soap) and glycerides. The PST comprises the reaction product of a fat or oil with a metal base, where the metal base is present in an insufficient amount to completely convert the ester to a soap. The reaction product is a homogeneous composition of a soap and a mixture of monoglyceride, diglyceride, and triglyceride with a minor amount of glycerine. By “homogeneous”, it is meant that the metal soap and glyceride components are uniformly dispersed in each other and behave as one phase.
It has been found under controlled reaction conditions that a homogeneous composition of partially saponified triglycerides is obtained in the absence of a compatibilizing agent such as has been found necessary in the prior art mentioned in the background of this invention.
According to the method of this invention, a triglyceride is reacted with a metal base in the presence of a catalyst. The metal base is selected from a class of metal oxides, hydroxides, and carbonates, preferably of the alkali metal and alkaline earth metal class, most preferably calcium or sodium hydroxide. The reaction may be conducted under anhydrous conditions, but it is preferred to react the components with a very minor amount of water on the order of about 0.1 to about 2 percent by weight. The use of a minor amount of water not only facilitates the reaction but eliminates the formation of the reaction products and offensive odors that occur under anhydrous conditions. A variety of catalysts may be employed but organic acids or their salts are especially preferred, particularly low molecular weight acids such as glacial acetic acid on the order of about 0.1 to about 2 percent by weight. It is necessary to conduct the reaction at a sufficiently high temperature for solubilization or homogenization of the metal salt in the glycerides reaction mixture. It has been found, for example, that reaction temperatures in excess of about 120° C., preferably about 150° C. to about 250° C., are necessary to achieve the solubilization of the fatty acid salt in the reaction mixture. By achieving this solubilization, homogeneous partially saponified triglycerides are obtained without the need for the addition of compatibilizing agents of the type set forth in the background of this invention. In other words, essentially pure homogeneous partially saponified triglycerides are achieved according to the methodology of this invention.
It has also been found that the homogeneous partially saponified triglycerides are very useful as polymer additives and in other areas. In particular, the homogeneous PSTs are suitable for use as lubricants in vinyl halide resin formulations, particularly PVC. The homogeneous PSTs also serve as antistats in PVC compositions. Polyolefin resins such as polypropylene and propylene-ethylene copolymers are neutralized against corrosive activity by the homogeneous PSTs.
SUMMARY OF BEST MODES OF PRACTICING THE INVENTION
The best modes of practice involve reaction of triglycerides with a small amount of an organic acid catalyst, water and a metal base to give a homogeneous composition of the respective soaps and mono-, di- and tri-glycerides. An important step in this preferred mode of reaction is to use an organic acid, such as glacial acetic acid or its salt, and a small amount of water. In order to achieve the homogeneity in the reaction product, it is important that after the fatty acids soaps start to come out of solution, that the soaps in the reaction mixture redissolve. There are a number of advantages associated with this method. For example, homogeneous PSTs are achieved as relatively thick liquids which can be pumped or completely emptied from the reaction vessel. It has been found that the homogeneous PSTs produced by this method avoid the need for compatibilizing agents such as oxidized polyethylene that heretofore has been found necessary in order to achieve homogeneity of the partially saponified triglycerides.
The catalysts are used in amounts of about 0.1 to about 2 parts by weight. A very minor amount of water is also preferably required, in the order of about 0.1 to about 2 percent by weight. While water may be eliminated, the total elimination causes objectionable odor, probably from the formation of polyglycerols and/or acrolein from the glycerine formed in the hydrolysis. While foam may develop because o
Dieckmann Dale J.
Nyberg Wayne H.
American Ingredients Company
Medley Margaret
Toomer Cephia D.
Wood Herron & Evans L.L.P.
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