Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
2003-03-04
2003-10-28
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S157000
Reexamination Certificate
active
06639090
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to powdered overbased amorphous alkaline earth metal salts of fatty acids and a process for producing them. The overbased powders are useful in many applications including polymer stabilizers, lubricants, catalysts, oil well compositions, animal nutrition and cosmetics.
BACKGROUND OF THE INVENTION
The preparation of overbased calcium or barium salts of carboxylic acids, alkyl phenols, and sulfonic acids are disclosed in the following U.S. Pat. Nos.: 2,616,904; 2,760,970; 2,767,164; 2,798,852; 2,802,816; 3,027,325; 3,031,284; 3,342,733; 3,533,975; 3,773,664; and 3,779,922. The use of these overbased metal salts in the halogen-containing organic polymer is described in the following U.S. Pat. Nos.: 4,159,973; 4,252,698; and 3,194,823. The use of overbased barium salt in stabilizer formulations has increased during recent years. This is due, in the main, to the fact that overbased barium salts possess performance advantages over the neutral barium salts. The performance advantages associated with overbased barium salts are low plate-out, excellent color hold, good long-term heat stability performance, good compatibility with the stabilizer components, etc. Unfortunately, most of the overbased barium salts are dark in color and, while these dark colored overbased barium salts are effective stabilizers for halogen-containing organic polymer, their dark color results in the discoloration of the end product. This feature essentially prohibits the use of dark colored overbased barium salts in applications where a light colored polymer product is desired.
According to the teachings of U.S. Pat. No. 4,665,117, light colored alkali or alkaline earth metal salts are prepared where alkyl phenol is used as a promoter. However, alkyl phenol is also a major cause for the development of color in the final product. This problem is overcome by the use of propylene oxide which displaces the hydrogen of the phenolic hydroxyl group and thereby restricts the formation of colored species. However, there are disadvantages associated with this approach, principally due to the toxic nature of propylene oxide. Propylene oxide is classified as a possible carcinogen and laboratory animal inhalation studies have shown evidence of a link to cancer. Propylene oxide is also listed as a severe eye irritant, and prolonged exposure to propylene oxide vapors may result in permanent damage to the eye. Furthermore, propylene oxide is extremely flammable and explosive in nature under certain conditions. Propylene oxide boils at 94° F. and flashes at −20° F. As a result, extreme precautions are required to handle propylene oxide at the plant site. Special storage equipment is required for propylene oxide and other safety features are necessary. U.S. Pat. No. 4,665,117 describes the use of propylene oxide at 150° C. At this temperature, propylene oxide will be in the gaseous phase. Under these operating conditions, more than stoichiometric amounts of propylene oxide are required to carry the reaction to completion because propylene oxide will escape from the reaction mixture and this requires additional handling of the excess propylene oxide.
With the movement in the plastics industry to remove heavy metals, liquid calcium-zinc stabilizers are desirous, but not practical, as replacements for barium-cadmium or barium-zinc. Low metal concentrations, poor compatibility, haziness in clear products and plate out during processing in PVC have severely limited the universal acceptance of calcium based liquid stabilizer compositions. Problems are encountered in the stability of these compositions upon standing or storage. Storage stability is due to the incompatibility among the metal salts employed in the composition and is exhibited by increased turbidity, viscosity, or insoluble solids over time. As a result, the liquid calcium compositions are no longer homogeneous or readily pourable and must be specially treated in order to be used. U.S. Pat. No. 5,322,872 is directed to stabilized compositions of mixed metal carboxylates having improved storage stability. According to this patent, a complexing agent is added to the mixed metal carboxylate in order to improve shelf stability. Complexing agents disclosed in this patent include phosphines, phosphites, aromatic cyanides, aromatic hydroxy compounds, oximes and other compounds. U.S. Pat. Nos. 5,830,935 and 5,859,267 have also issued as directed to processes for improving basic metal salts and stabilizing halogen-containing polymers therewith.
U.S. Pat. Nos. 3,766,066 ('066) and 3,766,067 ('067) disclose the preparation of solid calcium-containing micellar complexes from homogenized carbonated calcium overbased organic acid salts with the aid of “conversion agents” such as water and alcohols. The '067 patent teaches that to prepare the desired micellar complexes from the overbased salts it is first necessary to subject a solution of those salts in inert organic liquid diluents to a homogenization step with vigorous agitation in the presence of water, alcohols or mixtures of alcohols and water. The homogenization is accompanied by a “thickening” or “gelling” phenomenon to produce crystalline particles characterized by an x-ray diffraction pattern corresponding to that of calcite. However, x-ray diffraction studies of the starting salt solutions do not indicate the presence of any crystalline calcium carbonate. In fact, the '066 patent teaches that the calcium carbonate present in the starting non-homogenized solution appears to be amorphous. The amorphous metal salts or complexes present in the material are unquestionably transformed to crystalline particles on homogenization according to the '066 and '067 patents. U.S. Pat. No. 5,534,169 also teaches the conversion of a Newtonian overbased calcium carboxylate to a non-Newtonian dispersion of calcite particles in order to produce a material useful for reducing friction. U.S. Pat. No. 5,830,832 also discloses the preparation of powdered calcium overbased soaps from branched oxo-acids.
Notwithstanding the state of the art as exemplified by the above patents, there is a need for further improvements in overbased alkaline earth metal salts of fatty acids, methods for making them and their use in product applications.
SUMMARY
The present invention relates to a powdered overbased amorphous alkaline earth metal salt of a fatty acid. These powders comprise isolated solid agglomerated particles of an amorphous alkaline earth metal salt from the group consisting of carbonate, sulfate, sulfide and sulfite complexed with an amorphous alkaline earth metal carboxylate of a fatty acid. In a preferred form, the powders are alkaline earth metal carboxylates/carbonates. These powders are referred to sometimes hereinafter more simply as “powdered overbased amorphous alkaline earth metal salt(s)” or “powdered overbased amorphous alkaline earth metal carboxylate(s)/carbonate(s)”. Powdered overbased amorphous calcium and barium salts are preferably provided and, in a preferred form of the invention, the powders are essentially free of a phenol or a phenolic derivative. The powdered amorphous overbased salts are essentially solid particles which are agglomerated micelles of the amorphous metal salt, like the metal carbonate, complexed with the amorphous metal carboxylate. The agglomerated particles generally range from about 50 microns in size.
The invention also relates to a process for preparing the powdered overbased amorphous alkaline earth metal salts. The process involves reacting an alkaline earth metal base and a fatty acid with an equivalent ratio of metal base to fatty acid being greater than 1:1 in the presence of a liquid hydrocarbon. A surfactant and catalyst are used to promote the reaction. The mixture is acidified, preferably by carbonation, to produce an amorphous alkaline earth metal carbonate. In a preferred method, during carbonation, a dispersion of alkaline earth metal base, a liquid hydrocarbon, and an aliphatic alcohol having at least 8 c
Ramey Chester E.
Reddy James E.
Carr Deborah D.
OMG Americas, Inc.
Wood, Herron & Evans L.L.P
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