GB1592271A - Overtreated higher dialkyl dimethyl ammonium clay gellants and their use in greases - Google Patents

Description

(54) OVERTREATED HIGHER DLALKYL DIMETHYL AMMONIUM CLAY GELLANTS AND THEIR USE IN GREASES (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to novel thixotropic quaternary ammonium clay composi tions, namely C8 to C,5 dialkyl dimethyl ammonium clays, having layer and chain type structures. More particularly, this invention relates to thixotropic compositions containing overtreated gellant derivatives of layered clays having a high ion exchange capacity and the method of preparing the clays. The present derivatives of such clays are produced by treating mineral clays with a 12 to 25% excess arnount of the corresponding ammonium salt in a reaction medium which comprises water and a water miscible polar organic solvent. Such overtreated ammonium clays, particularly montmorillonites are superior gellants, e.g., for alkyd resin based coatings and polyolefin base lubricant oils.

That is to say, C8 to C, dialkyl dimethyl ammonium clays, of superior gellant effectiveness in oxygenated organic liquids and polyolefin can be produced by the overtreatment of layer and chain type mineral clays via ion exchange reactions. For example, a layered dioctadecyl dimethyl ammonium montmorillonite, a superior gellant for alkyd resin based coatings and polyolefin is prepared by the reaction of sodium montmorillonite with an excess of the corresponding quaternary chloride beyond the known ion exchange capacity of the clay. In the case of the oxygenated compounds the excess ranges from 12 to 25% above the ion exchange capacity of the clay. The overtreatment is preferably carried out in a mixture of water and organic solvent which disperses the clay and dissolves the quaternary ammonium salt.

Layered quaternary higher dialkyl dimethyl ammonium clays containing ammonium groups equivalent to the ion exchange capacity of the starting inorganic clay are known thixotropic gelling agents for toluene and other hydrocarbon solvents containing aromatic components. The properties and applications were reviewed by J. W. Jordan and F. J. Williams in an article, entitled " Organophylic Bentonites III, Inherent Pro perties" [Journal Kolloid-Zeitschrift 137, 40--48 (1954) j. The compositions and their uses are largely covered by patents of J. W. Jordan which are assigned to the National Lead Company, i.e. NL Industries. One of the basic patents issued to Jordan, i.e. U.S. Patent No. 2,531,440, provides a good summary of the state of the art as it relates to the present invention.

The above-referred Jordan patent states, from column 4, line 72 to column 5, line 26, that when preparing ammonium clay gellants, such as the higher dialkyl dimethyl ammonium montmorillonites, optimum gellant compositions are obtained by using equivalent reactants. The term "equivalent means that the clay reactant is contacted with amounts of the ammonium salt reactant which correspond to the ion exchange capacity of the clay. The ion exchange capacity of the clay is obtained by determining the amount of ammonium acetate which reacts with the clay when an excess of ammonium acetate is used as a reactant. See R. P. Graham and J. D. Sullivan, J. Am. Ceram.

Soc., 21, 176-183 (1938). The value of the ion exchange capacity is expressed in milliequivalents per 100 g. dry clay (me).

Furthermore, Jordan in U.S. Patent No. 2,531,440 describes from column 4, line 72 to column 5 line 10 and in Examples 1, 2, 4, particularly Example 4, that an advantageous method for the preparation of his compositions consists of reacting a dilute aqueous dispersion of sodium montmorillonite with the quaternary ammonium salt.

In general, the quaternary ammonium clays previously studied for grease applications are products of equivalent treatment of an organic clay by a quaternary ammonium salt.

For example, one of the Jordan patents, U.S. Patent No. 2,531,449 defines such a grease gellant as a quaternary ammonium derivative of a clay in which the exchangeable inorganic cations were replaced by the organophilic ammonium cation to an extent sufficient to swell, i.e. gel, nitrobenzene. Another patent, U.S. Patent No. 2,966,506, describes sach gellants, such as dioctadecyl dimethyl ammonium montmorillonite, as being derived by reacting, e.g., sodium montmorillonite with the appropriate quaternary ammonium salt in amounts corresponding to the ion exchange capacity of the clay as determined by the ammonium acetate method [Abraham and Sulivan, J. Am. Ceram.

Soc., 21, 176-183(1938)]. Publications related to the grease applications of commer cial dioctadecyl dimethyl ammonium montmorillonite, i.e. Bentone 34, are also con cerned with a typical product of equivalent treatment. For reference, see J. V. Kennedy and W. T. Granquist, Nat. Lub. Grease Inst. Spokesman, 29 (5) 138-145 (1965) and J. L. McAtee, Nat. Lub. Grease Inst. Spokesman, 32 (2) 52-60 (1969).

More specifically, the use of quaternary ammonium clays as gellants for hydro genated polyolefin based greases is described in U.S. Patent No. 3,514,401. The quaternary clays of this patent were again the result of equivalent clay treatment. One of the clays used in the examples of this patent was Bentone 34, (Registered Trade Mark) a commercial ditallow, dimethyl ammonium montmorillonite clay product of NL Industries, i.e. a Bentonite derived from a sodium montmorillonite from Wyoming.

The exchange of the sodium and calcium cations of a Wyoming montmorillonite, i.e. bentonite, having an ion exchange capacity of 92 m.e. by various amounts of qua ternary dimethyl dioctadecyl ammonium chloride was studied in aqueous media by J.

L. McAtee of the National Lead Co. lie reported in Amencan Mfneralogist, 4, 123(S 1236, (1955) that only sodium ions were exchanged by the quaternary ions up to and at the 90 m.e. quaternary salt treatment level. At the next higher treatment levels, 11 8 and 140 m.e. about 10 m.e. calcium iron and an additional 2 m.e. sodium ion were exchanged.

McAtee did not disclose either the properties of the overtreated clays or their uses.

However, J. W. Jordan reported previously [J. Phys. Colloid Chem. 53, 294-305, (1950) at page 304] that the swelling in nitrobenzene of a higher dialkyl dimethyl montmorillonite, i.e., dodecyl hexadecyl dimethyl ammonium bentonite, was adversely affected by overtreatment. Since the swelling of organo-clays usually parallels their gelling ability, this Jordan publication is an indication of the adverse effects of overtreatment on gelling efficacy. A similar adverse indication is provided in another paper by J. W. Jordan, B. J. Hook and C. M. Finlayson (J. Phys. Coil. Chem. 54, 1196- 1207 (1950) at page 1203) on the gel strength of toluene thickened by primary octadecyl ammonium bentonites of varying treatment level.

The ion exchange reactions of clays having a layer or chain type structure by treatment with up to a 100% excess of ammonium salts in C1 to C alcohol media were broadly disclosed in British patent No. 1,190,383 in 1966 by B. J. Fowled.

Although this disclosure was all inclusive, no specific quaternary ammonium salt reactant or product was named or described.

A recent monograph entitled "The Chemistry of Clay Organic Reactions" by B. K. G. Theng - a Holstead Press Book published by J. Wiley & Sons, New York (1974) particularly Chapter 5, pages 224, 229 to 232, makes it clear that the effect of clay overtreatment depends on the structure of the ammonium salt reactants. With regard to the properties of the organic ammonium clay products Theng stated that the hydrophilic character reaches a minimum, i.e. the lipophilic character a maximum at the ion exchange capacity. That means that on the basis of the prior art no improved organophilic gellants were expected from the overtreatment of clays.

In contrast to the prior art, it has now been discovered that C8 to C,1 dialkyl dimethyl ammonium clays, particularly montmorillonites impart unexpectedly desirable gellant properties in oxygenated organic liquids and polyolefin lubricant base fluids it the level of clay overtreatment is kept within certain limits. In studying the interaction of such overtreated clays with organic liquids of varying polarity and polyolefin lubri cant base fluids, it was discovered that they depend on clay overtreatment. As a result. the discoveries of the present invention have led to overtreated clay gellants for some organic liquids which could not be gelled by known clay gellants.

The clay derivatives used as gellants for the compositions of the present invention have a high ammonium cation and low anion content in relation to the inorganic clay part. The inherent gelling properties of the clay derivatives are superior to those of the related prior art compositions, e.g., these overtreated clay derivative gellants are more effective in polyolefin lubricant base fluids and non-hydrocarbons especially high moleclear weight liquids used for coating such as alkyd resins. This is a most important unexpected effect. The related prior art compositions are more effective in hydrocarbon solvents. In the prior art, only the hydrocarbon gelling effect of the prior art compositions was known.

The improvement of the gelling ability of the overtreated clay derivatives in oil based coatings free from aromatic hydrocarbon solvents is of particular importance due to current environmental considerations. Arornatic hydrocarbons such as toluene which were considered key coating components in known organo clay gellant interactions are to be essentially eliminated from environmentally acceptable coatings. The overtreated clays provide new possibilities for the formulation or acceptable thixotropic coatings.

In further contrast to the prior art, it has now been discovered that Cs to C,5 dialkyl dimethyl ammonium clays, particularly montmorillonites of onexpectedly desirable gellant properties in polyolefins are obtained via overtreatment. These polyolefins, e.g. polydecene, will provide greases, when mixed with the overtreated ammonium clays, such as dihydrogenated ditallow dimethyl ammonium montmorillonite. No grease is obtained under the same conditions when the corresponding clay of equivalent treatment is used.

The inherent gelling properties of the overtreated clay gellants for polyolefins are surprisingly different from those of the known clay gellants of equivalent treatment, in general. While the present gellants are unexpectedly superior in polyolefins, the known gellants are better in greases based on the more polar mineral oil based lubricant fluids.

The improvement represented by the synthetic hydrocarbon lubricant, e.g. polydecene, based grease compositions is particularly significant since such lubricants can be used over a wide range of operating conditions from very low to high temperatures.

These characteristics are highly desirable in aircraft applications where extremes in temperatures are frequently encountered.

Quaternary Cs to Cs, dialkyl dimethyl ammonium montmorillonite clay products containing ammonium ions in a concentration equivalent to the ion exchange capacity of the starting clay are known geilants for mineral oil based greases. However, these clays do not gel synthetic polyolefin based lubricating fluids under the same conditions.

In contrast, overtreated Cs to C,, dialkyl dimethyl ammonium montmorillonites can be used for gelling synthetic polyolefin based lubricating fluids.

Quaternary Cs to C,, dialkyl dimethyl ammonium montmorillonite clay products containing ammonium ions in a concentration equivalent to the ion exchange capacity of the starting clay are known gellants for aromatic hydrocarbons. The organophilic properties of such gellants depend on the polar character of the liquid to be gelled.

This observation led to this work, extending the study of correlations between gellant effectiveness and solvent polarity to overtreated clays.

It was furthermore found in the present invention that the overtreated Cs to C,, dialkyl dimethyl ammonium clays can be advantageously prepared using a mixture of water and a polar organic liquid such as isopropanol as reaction medi. Such media lead to an unexpectedly increased degree of ion exchange. This in turn results in having an increased amount of the quaternary ammonium salt component in the form of the aluminosilicate rather than the chloride derivative.

According to this invention, thixotropic compositions comprise a major amount of an oxygenated organic compound or a polyolefin lubricant base fluid and a quaternary Ss to C,, dialkyl dimethyl ammonium montmorillonite clay compositions of layer and chain type structure which contain ammonium ions in a concentration ranging from 12 to 25% above the ion exchange capacity of the clay as expressed in milliequivalents per 100 g. dry clay and as determined by the amount of ammonium acetate which reacts with the clay when an excess of ammonium acetate is used as a reactant.

In another aspect of the present invention there is provided a process for prepar ing quaternary higher dialkyl dimethyl ammonium clay compositions comprising, react ing a quaternary ammonium C, to C,, dialkyl dimethyl ammonium compound and a clay in reaction media comprising a mixture of water and a polar organic liquid.

In the following, the overtreated Cs to C1s dialkyl dimethyl ammonium clay gellants and their preparation are disclosed. It is shown that such overtreated clays, particularly montmorillonites, containing a 12 to 25% excess of the quaternary ion, have unexpectedly superior gellant properties and polyolefin in oxygenated organic compounds, such as alkyd type polyesters, although they are inferior in aromatic hydrocarbons such as toluene.

Product Compositions The quaternary C5 to Cs, dialkyl dimethyl ammonium clays useful in the present invention can be represented by the general formula:

wherein each R is the same or different and is a Cs to C, saturated n-alkyl group. It is preferred that R ranges from C14 to C22. In the most preferred case R ranges from C2.6 to C6. It is specifically preferred that R be a hydrogenated tallow group. The term " Clay " designates a layered or fibrous crystalline aluminosilicate of high ion exchange capacity and mineral origin. Sodium and unsubstitnted ammonium alumino-silicates having 25 to 200 milliequivalent (me) of exchangeable cations per 100 g. are preferred.

Even more preferred are clays having ion exchange capacities ranging from 50 to 170 m.e. per 100 g. The most preferred clays have 80 to 120 m.e. ion exchange capacity per 100 g. Layered type clays are structurally preferred, particularly the three layer class. It is most preferred to use a montmorillonite type clay in the sodium salt form.

The symbol "X" represents an anion and is a chloride, C1 to C15 carboxylate, sulfate, C2 to Cs dialkyl phosphate or phosphite or C1 to C,5 sulfonate. Examples are formate, octanoate, dimethyl phosphate, dibutyl phosphite, methanesulfonate and dodecylbenzenesulfonate. X is preferably chloride or acetate and most preferably chloride.

The symbols m and n are positive integers, with the provlso that m is greater than n. The symbol "m" represents the number of quaternary ammonium cations in the composition and the symbol "n" represents the number of negative changes on an aluminosilicate moiety, i.e., particles which are balanced by exchangeable cations in the starting inorganic clay. The symbol "n" is related to ion exchange capacities of clays as discussed in the monograph er.titled "Clay Mineralogy " by R. E. Grim, published by McGraw Hill, Inc. New York (1968). These ion exchange capacities are usually known on the basis of the extent of the sodium clay plus excess ammonium acetate reaction.

As a consequence, the compositions can contain some X anions, e.g., chloride anions, to help to preserve the principle of electroneutrality of salts. The symbol "k" in the formula represents the number of anions. As such, "k" can range from 0 to rn-n. It is, however, preferred that k be 1 to 50. The difference between n and m is preferably 5 to 30. Most preferably, k ranges from 12 to 25.

In the case of a typical Wyoming sodium montmorillonite, the values of the above numbers may range as follows: n 80-100; m=102116, preferably 105 to 111; k=0 to 20, preferably 1 to 10. Optimum products are derived in ion exchange reactions by maximizing the value of m and minimizing that of the k.

Exemplary clay compositions are dioctyl, ditetradecyl, dihexadecyl, dioctadecyl, diheptadecyl, dieicosyl, didocosyl, ditriacontyl and dipentatriacontyl, dimethyl ammonium derivatives of montmorillonite, hectorite, attapulgite, vermiculite, etc., containing, e.g. chloride anions.

In terms of overtreatment, the overtreated clay gellants contain 12 to 25 excess, preferably a 15 to 20% excess of the quaternary ion moiety.

OVERTREATMENT PROCESS The quaternary higher alkyl dialkyl dimethyl ammonium clay can be prepared by reacting a clay, preferably sodium clays with an excess of a higher dialkyl dimethyl ammonium salt, above the known ion exchange values as indicated by the following reaction scheme: m [R2N+(CH3)2] X-.+ [Clay"-] n/yMe- m [R2N+(CH3)2j Clay-1.kX + n/y MeX wherein Me is Na, K, NH4, Ca, Mg preferably Na, NH4, most preferably Na, y is 1 or 2, preferably 1 and the other symbols have meanings previously defined. When X is monovalent, m has the same value as k.

The type of clay mineral to be used may vary with the intended use. Among the preferred clays are those having crystalline, layer type structures. For optimum gelling properties, it is best to use a three layer type montmorillonite which exhibits good swelling properties in water and a high ion exchange capacity. However, sorne nonswelling clays, when converted to the ammonium salt form, will swell in organic liquids and give rise to thixotropic colloidal dispersions. The latter clays such as the two layer type kaolinites can be also used. Another useful clay is the chain structure type attapulgite. The clays particularly contemplated are the alkali metal and alkali earth metal montomorillonites, e.g. sodium and potassium, montmorillonites particularly of the Wyoming type, most specifically naturally occurring sodium montmorillonite.

These clays are particularly characterized by an unbalanced crystal lattice, are believed to have negative charges which are normally neutralized by inorganic cations.

As found in nature, therefore, they exist as salts of the clay acid with bases such as the alkali or alkaline-earth metal hydroxides. The base-exchange capacities of the various clays enumerated generally range from about 25 to about 100, based upon milliequivalents of ammonium acetate exchangeable base per 100 grams of clay. The montmorillonites have comparatively high base-exchange capacities, viz., 60-100. Attapulgite has substantial base-exchange capacity, viz., 25-35. Generally, the clays of higher baseexchange capacities are particularly preferred.

Surprisingly, the products of the present invention, having inherently better gelling properties, are prepared when the reaction is carried out in a mixture of a polar organic solvent and water rather than in water alone. The organic solvent is miscible with the water and is preferably a C1 to C12 alcohol, a ketone, an ether, a nitrile, a sulfone, a carboxylic acid, a carboxylic ester or an amide. Solvents in the Cl to C4 range are preferred, particularly, the alcohols. Exemplary solvents are methanol, dodecanediol, methylethylketone, dimethyl ether, dioxane, furane acetonitrile, pyrrolidone, dimethyl sulfone, acetic acid, methyl acetate, dimethyl formamide. Isopropanol is most preferred.

The ratio of the solvent to water in the reaction media is not critical, provided that the quaternary salt reactant is dissolved and the starting clay is dispersed in the medium. The preferred solvent to water ratio ranges from 1:20 to 2:1, more preferably from 1:10 to 1:3.

The unexpected effect of the solvent chemically manifests itself in higher conversions, i.e., higher values of the m and lower values of the k in the product. This effect is particularly critical when making the novel compositions having an excess of the quaternary ammonium groups.

The reaction does not depend on the temperature. From the practical point of view it is carried out below the boiling point of the solvent mixture and above the freezing point of water. Preferred temperatures are between 10 and 900. Slightly elevated temperatures between 40 and 80" are even more preferred since they result in an increased solubility of the quaternary salt reactants.

The ratio of the quaternary salt reactant to the clay corresponds to the ratio of m to n in the product. Surprisingly, the ammonium group is essentially quantitatively incorporated into the product. The ammonium saft is used as a solution. This is added to the suspension of the clay at as fast a rate as practicable. A salt solution may be combined with a clay suspension in a flow system to produce the reaction mixture.

The reaction is very fast. The combination of the reactants results in an immediate sharp increase of the viscosity of the clay mixture. Within a few minutes this is followed by a reduction of the viscosity due to the separation of macroscopic product particles. The product is usually separated within a few hours by filtration and may be washed before drying. The particle size of the dry product is usually reduced below 200 mesh size by known means of pulverizing and milling before or during its use.

The reaction does not depend on the concentration of the reactants. However, to prepare the preferred compositions in a practical manner it is important to have the rlay in the form of well stirrable colloidal suspension. The clay concentration is pre ferably 0.5 to 10%, more preferably 1 to 5%. The quaternary salt is preferably in solution of a concentration of preferably 3 to 80% more preferably 5 to 20%.

PRODUCT PROPERTIES The properties of the products are largely dependent on their microstructure. For example, in the case of the layered montmorillonite derivatives, a characteristic of the microstructure is the interplanar spacing. This is the repeat distance between the aluminosilicate layers. It has been found that in the case of the overtreated clays, this distance is surprisingly dependent on the number of carbon atoms of the higher n-alkyl substituents of the quaternary ammonium moieties. Such a dependence in the C14 td C18 alkyl range is in contrast with the prior art observations by Jordan on monoalkyl ammonium clays of the same carbon range. This indicates an unexpected difference between the microstructure of over-treated ammonium clays and the stoichiometric compositions reported previously. The microstructure presently found is due to a certain orientation of the higher alkyl groups between the aluminosilicate layers in a manner described for quaternary phosphonium clays by A. A. Oswald in U.S. Patent 3,929,849.

POLAR ORGANIC COMPOUNDS The novel compositions are unexpectedly useful as thixotropic components of polar organic liquids of preferably nonhydrocarbon character, more preferably oxygenated organic compounds, parxicularly oxygenated organic polymers, more particularly polyesters wherein related prior art compositions are not effective. The present compositions are specifically useful in the so-called alkyd resins. The latter are polyesters derived from fatty acids such as stearic acid, polyols such as glycerol or glycol and dicarboxylic acids such as phthalic anhydride.

Certain types of alkyds, the so-called long oil alkyd resins are the most commonly used base for general purpose industrial coatings. Such base resins are usually diluted with minor amounts of a hydrocarbon solvent. For example, 30% of mineral spirits may be employed.

The present compositions in general will provide improved thixotropic compositions in polyesters including unsaturated polyesters such as those described in U.S.

Patent No. 3,974,125 by Oswald and Barnum. Among other oxygenated compounds are as example 3 polyalkylene terephthalates, nylon type polyamides, epoxide resins. An example of nonhydrocarbons containing no oxygen is polyvinyl chloride.

Related prior art thixotropic gellants are known to interact with the hydrocarbon solvent. The present gellants surprisingly interact with nonhydrocarbons. The latter activity depends on the-presence of excess quaternary ammonium groups in the present compositions. Dependent on the amount of this excess, the activity of the present compositions shows an unexpected optimum. The ammonium excess in the optimum composition is dependent on the structure of the quaternary ammonium moiety, the aluminosilicate and the anion present.

POLYOLEFINS The polyolefin components of the nonpolar compositions such as greases of the invention are preferably derived from C2 to C12 olefins, more preferably from C8 to C12 olefins.

The C8 to C12 polyolefin components are preferably derived from a-olefins. It is furthermore preferred that said a-otefins be polymerized by cationic catalysts. During the polymerization the a-olefins can undergo isomerization reactions which increase the branchiness of the polyolefin products. A high degree of branching of the polyolefin base fluids is preferred because it reduces their pour points. However, long straight alkyl segments are desired for an increased interaction with the gelling agent and stability.

The preparation of preferred polyolefin components is illustrated in U.S. Patent Nos. 3,149,178; 3,156,736 and 3,842,134. The polyolefin components are more preferably hydrogenated in a subsequent treating process to saturate all the double bonds.

A detailed description of conducting such a treatment is found in U.S. Patent No.

3,149,178. The resulting polyolefin derived products of completely saturated aliphatic, i.e. paraffinic character are of superior stability.

PLASTICS AND ELASTOMERS The grease compositions of the invention which include the polyolefin and the overtreated clays can be used in reinforced plastics and elastomers applications. For such applications, the preferred polymers are derived from C3 toC6 olefins.

Exemplary polymers are polypropylene, hydrogenated copolymers of butadiene and styrene, ethylene-propylene-diene terpolymers. The method of such application is described in U.S. Patent No. 2,531,396.

Greases The present thixotropic compositions, preferably comprising major amounts, preferably 80 to 95%, of C to C8 polyolefin lubricating base fluids and minor amounts, preferably 5 to 15%, of overtreated higher dialkyl dimethyl ammonium montmorillonite gellants, possess preferred viscosity behavior, i.e. rheology, stability and lubricating characteristics. These properties allow their advantageous application as greases. The grea then filtered with suction at the same temperature. The products were washed for filtration three times on the Buchner-funnel by fresh aqueous isopropanol of the com poblblon used in the reaction. The fifth wash employed water. At the 30 g. starting clay level the volume of liquid for one wash was 300 ml. Products having increasing alkyl substituents were increasingly hydrophobic and easy to filter. The washed, filtered products nevertheless still had a water content of about 90%. They were dried under 0.1 mm pressure either at ambient temperature or at 600 C. The dry products were ball milled overnight and then passed through a 200 mesh screen. Thereafter, they were analyzed and evaluated. Their interplanar spacings of the 001 reflection by X-ray and elemental compositions are shown in Table I.

The interplanar spacing of the products as determined by X-ray diffraction analysis, i.e., the repeat distance between the layers was much larger than that of the starting clay, l20Avs. 18"A or greater. The interplanar distance of the products was increasing with the length of the higher alkyl substituents of the quaternary nitrogen.

In the case of the C8 to C28 derivatives the change of this distance per two carbon increase of the alkyl substituents was decreasing. Overall the definite changes in the C14 to C18 alkyl range were in contrast with the observations of Jordan on monoalkylammonium montmorillonites of the same range. Jordan reported no change whatsoever in this region [Journal of Physical and Colloid Chemistry 53, 297 (1950)]. This indicates an unexpected difference between the microstructure of the present ammonium clays and of those reported previously. This microstructure is apparently differentiated by the various orientations of the higher alkyl groups between the aluminosilicate layers.

As it is also shcwn by Table I, the found elemental composition of the clays was in fair agreement with the calculated compositions assuming the attachment of all the ammonium groups to the clay. The chlorine content of the products is low indicating that the clay undergoes the reaction with the large higher dialkyl dimethyl ammonium ion beyond its prior art ion exchange capacity.

TABLE I Interplanar Spacing and Composition of Quaternary Higher Dialkyl Dimethyl Ammonium Montmorillonite Clays [R2N+(CH3)2]m Clayn-.Clk Elemental Composition of Quaternary Clay, % Calcd for 99 me Salt i-Propanol X-Ray per 100g Clay Reaction Found in Water Seq. Exp. No. Structure Spacing Reaction No. E- of, n- d001 A C H N C H N Cl Medium, % 1 2708-II C8H17 18.0 17.19 3.21 1.11 18.46 3.82 1.21 0.17 0 2 2703-II C10H21 21.1-21.5 20.11 3.69 1.07 19.38 3.84 0.79 0.12 20 3 2723-II C14H29 23.8 25.27 4.52 0.98 24.92 4.81 1.03 0.08 23 4 2610-II C16H33 25.2 27.59 4.91 0.95 28.55 5.41 0.78 0.09 30 5 2803-II C18H37 26.8 29.67 5.24 0.91 29.32 5.41 1.06 0.03 33 6 2639-II C20-22H41-45 31.5 31.95 5.61 0.86 33.94 6.40 1.03 0.10 50 EXAMPLE 2.

Preparation of Quaternary Ditallow Dimethyl Ammonium Montmorillonite Composi tions Having About 0 to 30% Excess of The Ammonium Moiety The refined montmorillonite of Example 1 was also reacted with various quantities of a technical hydrogenated ditallow dimethyl ammonium chloride derived from hydrogenated tallow oil. As such, a quaternary higher dialkyl dimethyl ammonium chloride was used wherein 60% of the alkyl groups had 18 carbon atoms 35% was C18 and 5% C24. This product was obtained from the Ashland Chemical Company under the trade name Adogen 442-75. This commercial product composition had 75% quaternary salt, 20% isopropanol and 5% water. At room temperature the product is a waxlike solid, but it is easily melted to provide a clear liquid mixture. The quaternary salt is not significantly soluble in cold water but it is readily soluble in aqueous isopropanol.

The preparation and analyses of Adogen-442--75 modified montmorillonites are summarized in Table II.

The ditallow dimethyl ammonium montmorillonites of Table II were derived by using various quantities of the quaternary salt reagent per 100 g. dry clay, ranging from amounts corresponding to the ion exchange capacity (90 me) to 35% excess (121 me).

Some of the clay modifications were carried out in water, others used a 4 to 1 mixture of water and isopropanol. The large scale reactions were run at ambient temperatures (Seq. Nos. 2--4). The laboratory preparations were carried out at 55--600C. in the manner described in the previous example (Seq. Nos. 5-9). The concentration of the clay in the reaction mixture ranged from 2 to 3%. The Adogen 442-75 was added either as such or as a 510% solution in a liquid having an identical composition with the clay dispersion medium.

The analysis of a commercial dimethyl ditallow ammonium clay product of the Georgia Kaolin Co., Astratone-40, is shown for comparison under Sequence No. 2 of Table I. Pilot plant preparations were carried out using a sodium montmorillonite slurry (Seq. Nos. 2 and 3) in equivalent and excess amounts. This slurry was prepared from a crude sodium montmorillonite clay mined and dried in Wyoming.

TABLE II Elemental Composition of Quaternary Dimethyl Ditallow Ammonium Montmorillonites Preapred Via Ion Exchange Reactions Using Various Quantities of the Quaternary Chloride Reagent Treatment Level Isopropanol Adogen, % me Reactant in Water, % Rx (Conc. in Seq. Exp. No. of per 100 g Designation of (Clay in Reactant Temp.

No. Clay Prep. Dry Clay Strarting Clay Mixture, %) Solution) C.

1 Nil MCBP 2 E-2811-I 90 (Astratone 40) 0 (3) Ambient 100 3 E-2839-VII 91 Suspension 0 (3) Ambient 100 4 E-2840-VII 102 Suspension 0 (3) Ambient 100 5 E-2682-III 101 MCBP 20 (2) 60 10 6 E-2686-III 0 (2) 100 7 E-2690-III 111 MCBP 20 (3) 55 5 8 E-2697-III 116 MCBP 20 (2) 57 10 9 E-2698-I 121 MCBP 20 (2) 57 10 TABLE II (Cont'd) Elemental Composition of Quaternary Dimethyl Ditallow Ammonium Montmorillonites Prepared Via Ion Exchange Reactions Using Various Quantities of the Quaternary Chloride Reagent Calculated Composition, % Treatment Level 90 me Salt/100g Clay All Salt/100g Clay me Reactant Conversion Conversion Found Composition % Seq. Exp. No. of per 100 g No. Clay Prep. Dry Clay C H N Cl C H N C H N Cl 1 Nil 2 E-2811-I 90 29.96 4.79 0.86 0.00 29.96 4.76 0.86 28.82 5.48 1.07 0.71 3 E-2839-VII 91 27.16 5.17 0.94 0.02 27.16 4.81 0.87 27.21 4.84 0.99 0.57 4 E-2840-VII 102 29.19 5.17 0.94 0.28 29.32 5.20 0.94 28.89 5.34 0.91 0.75 5 E-2682-III 101 29.01 5.09 0.93 0.26 29.13 5.16 0.93 30.11 5.75 1.03 0.09 6 E-2686-III 7 E-2690-III 111 30.73 5.45 0.99 0.47 30.97 5.49 0.99 32.58 6.09 1.12 0.29 8 E-2697-III 116 31.56 5.60 1.01 0.57 31.85 5.64 1.02 33.28 6.22 1.09 0.39 9 E-2698-I 121 32.34 5.73 1.03 0.67 32.70 5.79 1.05 34.01 6.35 1.05 0.40 The crude clay (900 lib., i.e. 408 kg.) and Calgon hexametaphosphate dispersant additive (1.5 lib., i.e. 680 g.) were mixed with water (1218 gal., i.e., 4610 liter) for 30 minutes using a Strucher-Wells high speed mixer. The large particle size impurities were then removed from the resulting water gel by passing it through a 100 mesh screen. Thereafter, the finer impurities having a larger than 2 microns size were removed by a DeLaval centrifuge. The resulting stable dispersion had a pH of 8.1.

The refining of the crude clay of 8.85% solids content resulted in a slurry of 3.12% concentration. This slurry was prepared five days in advance. It was then kept in a holding tank at 60 C. since there was no provision for heating the pilot plant reactor vessels.

In both of the pilot plant preparations, 200 gal. of the slurry was used in a poly ethylene tank. The Adogen 44275 was melted at 50"C. The melt was added over a 5 min. period to the slurry which was stirred at 160 rpm at 500 C.

In the case of the 90 milliequivalent treatment, the addition of the quaternary salt (23.28 moles) resulted only in a moderate thickening followed by a rapid viscosity de crease. In contrast, the 99 me. treatment (with 44.1 Ibs. Adogen 442 containing 25.6 moles quaternary salt) resulted in substantial but not excessive thickening.

After about 35 minutes stirring both ammonium clay products were filter pressed.

In the case of the lower treatment a filter pressure of 30 Ibis. was sufficient for getting a sufficiently moisture free cake. The more highly treated product required 60 Ibs. for effective filtration. Also, the higher treatment resulted in a foamy, slightly cloudy rather than clear aqueous filtrate.

Both ammonium clays were air dried overnight in an air blown heated oven after filtration. However, by accident the overtreated clay was dried at 70 rather than 600 C.

This had no apparent effect. After drying, both products were pulverized.

The analyses of the quaternary ditallow dimethyl ammonium montmorillonites of Table I, in general, show that the organic content of the clay products is increasing with the level of treatment by the quaternary salt. This indicates that the quaternary groups are retained on the clay in quantities in excess of the ion exchange capacity.

The found clay compositions were compared with compositions calculated assum ing either the reaction of only equivalent or the reaction of all added quaternary salt.

The comparison of the chlorine values showed that, in the case of treatment in iso propanol-water high excess, more than an equivalent but not all the quaternary salt entered the ion exchange (Seq. No. 8 and 9).

In water medium, the reactions were apparently conversions limited as indicated by the relatively high chlorine contents (Seq. Nos. 24, 6). In these cases, much of the quaternary reagent remained in the chloride form. The difference caused by the substitution of water by isopropanolic water is particularly shown by the data of the fifth and sixth experiments. The chlorine content of the product was reduced to less than one-third when alcohol was present (Seq. Nos. 5 and 6). At the same time the carbon contenr increased rather than decreased indicating that the retention of the ammonium groups on the clay was not adversely affected.

To learn about the change of the concentration of metal cations as a function of the treatment level several of the clays of Table I were also analyzed for Na, K and Ca. The values found, were then compared with those for the starting MCBP clay: Elemental Composition, Exp. Treatment X-Ray Found, % No. Level Spacing E me/100 g. OA Na K Ca Nil 2.150 0.159 0.304 2812-I 90 26.4 0.386 0.099 0.058 2682-III 99 12.8 26.7 0.038 0.088 0.058 2690-III 110 12.6 31.5 0.038 0.021 0.050 2698-III 120 12.8 21.0 35.5 0.038 0.066 0.029 The comparison showed that up to the 120 me treatment level, the metal ion con Penetration was independent from the degree of overtreatment. (The high ion concentrations of the commercial products Astratone 40, were mainly due to incomplete washing.) A significant, but minor change in the concentration of K and Ca seemed to occur at the 120 me treatment level.

The X-ray spacing of the clays of various treatment level indicated changes in microstructure. With overtreatment, an increased d801 spacing is observed, indicating that the angle of the higher alkyl groups relative to the aluminosilicate layer is increased.

Additional peaks are also observed in the spectra. These peaks, the 12.7s peak probably originating from a d882 reflection, indicate new phase formation on overtreatment.

THE METHODS USED TO DETERMINE GELLING ABILITY All the gel test methods give somewhat different results if organic clays of various particle size are used. Therefore, the dry, ball milled clays were all passed through a 200 mesh screen before testing.

A. The Alkyd Resin Gel Test Alkyd resins are in general, polyesters derived from fatty acids, polyols such as glycerol or glycol, and dicarboxylic acids, usually phthalic anhydride. The resins used in the present tests were long oil alkyd resins, which are most commonly used for general purpose industrial coatings. They were obtained from Reichhold Chemical under the name Beckosol P-296-70 (Registered Trade Mark) with a computer code number 10-045. The product contains 30% mineral spirits as a solvent. The solid resin (70%) is derived using about 65% soybean oi!, 24% phthalic anhydride and 11% glycerol As such, the product meets federal specification, classification TTR 2660A, Type Class A, vinyl compatible. Its Gardner-Holdt viscosity is Y-Z2. The viscosity of the products supplied was apparently significantly different on the Brookfield scale, when determined using a number three spindle.

For the viscosity determinations, fluid is poured into a pint can where the viscosity readings are taken using a Brookfield viscometer with a number three spindle. The spindle is inserted to the near side of the jar and then moved to the center. Then viscosity readings are taken from low to high stirring rates: at 10 rpm after 40 seconds at this speed, at 20 rpm after 30 seconds, at 50 rpm after 20 seconds and at 100 rpm after 15 seconds. After the viscosity readings, the temperature in the rear side of jar is usually about 300C. and at the center 35 C.

In the alkyd resin gel tests, three batches of Beckosol P-296-70 were used.

Their viscosity characteristics, as determined by the Brookfield viscosimeter, were somewhat different as indicated by the following tabulation: Batch Identification Brookfield Viscosities, cps, of Long of Resin Oil Alkyd Resins After 18-24 hours Beckosol P-296-70 (at various Stirring Rates, rpm) (10) (20) (50) (100) A 2800 3000 3120 3200 B 2000 2200 2400 2400 C 2400 2500 2640 2620 The different batches of the resin showed different responses to the higher dialkyl dimethyl ammonium clay gellants. Therefore, strictly speaking, the data are comparable only when the same batch of resin was used.

The response of these resins to organic clay gellants was determined using available commercial quaternary dimethyl dihydrogenated tallow ammonium clays, as standards, having equivalent amounts of the quaternary group on the clay. The Astratone 40 standard is manufactured by the Georgia Kaolin Co. starting with refined sodium montmorillonite, basically the same clay which was used in our Examples 1 and 2. The Bentone 38 standard is manufactured by N. L. Industries from refined sodium hectorite. The effectiveness of these two ammonium clays in the three batches of alkyd resin was as shown by the following tabulation.

Brookfield Viscosities of Long Oil Alkyd Batch Identification Resins After 18-24 Hrs.

Dimethyl Ditallow of Resin Beckosol At Various Stirring Ammonium Clay P-296-70 Rates (rpm) (10) (20) (50) (100) Astratone-40 A 6000 5400 5120 4940 Bentone-38 A 6800 6200 5680 5320 Astratone-40 B 3200 3100 3040 2960 Bentone-38 B 4400 4000 3760 3540 Astratone-40 C 3400 3400 3280 3120 Bentone-38 C 4400 4200 3920 3740 In the test procedure, 1.25 g of ammonium clay is slowly added to 88 g. resin, while stirring it with a high speed, i.e., high shear mixer (with a drill press equipped with a circular Cowle's blade). After mixing for about two to five minutes, a polar sol vent mixture consisting of 95% propylene carbonate and 5% water is added in an amount equaling 33% of the clay while stirring to give optimum dispersion and highest viscosity. Thereafter, stirring is continued for an additional five minutes. The resulting gel is then thinned using a solvent, i.e., 10 g odorless mineral spirit, to reduce the vis cosity. Viscosity measurements of the resulting mixtures are made in 18 to 24 hours after the air bubbles formed during the stirring rose out of the liquid gels.

B. The Toluene Gel Strength Test To 294 g. toluene placed into a Waring blender, 6 g. of higher dialkyl dimethyl ammonium clay is added in 45 seconds while it is stirred at a rate of about 10,000 rpm (transformer setting 25). The resulting mixture is then stirred at 15,000 rpm for 90 seconds (transformer setting 100). The stirring rate is then reduced to 13,000 and 2.3 ml polar addictive, consisting of 95% commercial (i.e., 99%) methanol and 5% distilled water is added over 30 seconds. The speed is then again increased to 15,000 rpm and the stirring continued for a further 3 minutes.

The gel is then poured into a pint jar which is subsequently rocked and swirled for 30 seconds to remove most of the air bubbles. The jar is then capped tight and put into a 25 C. water bath. After fifteen minutes and 34 hours, viscosity readings are taken in the manner previously described. Between the 10 minutes and 24 hours reading, the jar is capped and set in a 25 C. water bath until the 24 hour reading.

C. The Unsaturated Polyester Test Unsaturated polyesters are polyesters of a dicarboxylic acid and a diol having a major amount of olefinic unsaturation. Such esters are more extensively defined in U.S.

Patent 3,974,125. This patent also describes in detail the styrene pregel method used in the present test. Throughout this work a common unsaturated polyester derived via the esterification of maleic anhydride, phthalic anhydride, propylene glycol mixture was used. It is commercially produced by the Reichhold Chemical Company and sold e.g. as a 60% polyester, 40% styrene liquid mixture under the number 33-072, 64005.

Styrene pregels were prepared usually at the 6% higher dialkyl dimethyl ammo nium clay gellant level by adding the appropriate quaternary clay having less than 200 mesh particle size to polymerization grade styrene stabilized with 50 ppm t-butyl cate chol. In a standard test, 3 g. of gellant and 50 g. styrene were placed into a 9.5 cm high, 8.5 cm diameter metal can. The contents were then stirred on a Rockwell Delta 6 Plus 6 15 in. drill press, equipped with a 5 cm wide "Cowles Blade ", at 725 rpm to obtain the pregel which was then usually employed for gelling the polyester composition.

An 80% polyester -- 20% styrene resin was used to make gels containing 40% styrene by adding approximately one part pregel to three parts of the resin.

In a typical procedure 52 g. of the styrene pregel was added to 148 g. of the liquid 80% polyester -- 20% styrene mixture, using stirring by drill press as des cribed earlier. After 15 minutes stirring, the resulting gels were closed to avoid evaporation, stored at ambient temperatures and/or at 24"C. Viscosity measurements were carried out after 15 minutes and 24 hours using a Brookfield LVT Viscometer with a number 3 spindle at 6 and 60 rpm stirring rate, generally at 240 C.

EXAMPLE 3.

(Comparative) Gelling Effectiveness of Various Higher Dialkyl Dimethyl Ammonium Montmorillo nite Clays in Alkyd Resins The clay preparations of Example 1, containing 10% excess of the ammonium moiety were tested as gellants in alkyd resins in the manner previously described. The results are shown in Table III.

TABLE III GEL STRENGTHS IN GENERAL PURPOSE LONG OIL ALKYD RESINS OF QUATERNARY HIGHER DIALKYL DIMETHYL AMMONIUM MONTIMORILLONITES Brookfield Viscosities, cps After 18-24 Hrs.

(At Various Stirring Rates, rpm) Alkyd Seq. Exp. No. Structure Resin No. E- of R, n- (10) (20) (50) (100) Useda 1 2708-IVb C8H17 3400 3300 3280 3240 B 2 2703-IIIb C10H21 2400 2400 2600 2700 B 3 2609-III C12H25 4800 4800 4960 4880 A 4 2723-IVb C14H29 5000 4500 4200 3960 C 5 2610-IIIb C16H33 9400 8200 7200 6480 A 6 2692-IIIb C18H37 8000 7000 5880 5560 A 7 2639-IIIb C20-22H41-45 5200 5300 5200 5120 A a Described under the test methods. b Clay composition described in Table I.

The data of Table III show that all the higher dialkyl dimethyl ammonium clays had a gelling effect on the alkyd resins. The gelling effect of the dioctyl derivative (Seq. No. 1) wwas particularly surprising since the prior art workers stated that the presence of higher than decyl group was necessary for a gelling effect.

Although all the clays tested were gellants not all of them had a significant thixotropic effect. Only the C14 to C18 derivatives increased the viscosity of the alkyds significantly more at low than at high stirring rates (Seq. Nos. 4-6). Surprisingly, the hexadecyl derivative seemed to be the most effective thixotropic gelling agent.

EXAMPLE 4.

Gelling Effectiveness of Ditallow Dimethyl Ammonium Montmorillonite Clays in an Alkyd Resin and in Toluene as a Function of Their Degree of Overtreatment.

The gelling effectiveness in an alkyd resin and in toluene of sodium montmorillonite treated with various quantities of Adogen 442-75 was examined by the test methods described earlier. The preparation of the variously overtreated clays was given in Example 2. In the present example, viscosities were determined in a general purpose long oil alkyd resin containing 1.4% of the experimental gellants and in toluene having 2% gellant concentrations.

The test results are given in Table IV. The table also shows the styrene swell, which is determined by slowly adding using a spatula 2 g. of an ammonium clay sample to 100 ml polymerization grade styrene. The styrene was contained in a 100 ml measuring cylinder of about 2.5 cm diameter. On the addition of the clay gelling agents, a spontaneous gelling occurred. The resulting gel volume of the clays was severalfold of the original by the time they fell to the bottom of the cylinder. The volume of the resulting bottom gel " phase " was read after 15 minutes, 2 hours and 24 hours.

The viscosity data of the table show different responses to overtreated clay gellants in alkyd resins and in toluene. In the alkyd resin the moderately overtreated clay showed optimum effectiveness when prepared in aqueous isopropanol (Seq. No. 3).

Furthermore, severe overtreatment did not significantly reduce the gel strength in the alkyd (Seq. Nos. 4-6). In contrast, in toluene the moderately overtreated clay was effective only when prepared in water (Seq. No. 2 vs. 3). The more severely overtreated clays had no significant gellant activity in toluene (Seq. Nos. 4-6).

TABLE IV GELLING EFFECTIVENESS OF DITALLOW DIMETHYL AMMONIUM MONTMORILLONITE CLAYS AS A FUNCTION OF THEIR DEGREE OF OVERTREATMENT Brookfield Viscosities, cps.

In long Oil Alkyd Resin 20% After 18-24 Hours [(Tallow)2N+(CH3)2]Cl- i-Propanol (At various Stirring Rates, rpm) Seq. me/100g Dry Clay in Water No. (Exp. No. E-) Medium (10) (20) (50) (100) 1 90 (2811-I) No 5200 5200 4960 4880 2 101 (2686)-III) No 6400 5800 5280 4900 3 101 (2682-III) Yes 8000 7000 5880 5280 4 111 (2690-III) Yes 6800 6000 5360 5600 5 116 (2697-III) Yes 6400 6000 5280 5080 6 121 (2698-III) Yes 6200 5700 5280 4880 TABLE IV (Continued) GELLING EFFECTIVENESS OF DITALLOW DIMETHYL AMMONIUM MONTMORILLONITE CLAYS AS A FUNCTION OF THEIR DEGREE OF OVERTREATMENT Brookfield Viscosities, cps (At Various Stirring Rates, rpm) In Toluene Styrene 20% Swell [(Tallow)2N+(CH3)2]Cl- i-Propanol After 15 Minutes After 24 Hours Ml Seq. me/100g Dry Clay in Water No. (Exp. No. E-) Medium (10) (20) (50) (100) (10) (20) (50) (100) 2 Hr. 24 Hr.

1 90 (2811-I) No 320 132 62 41 304 160 83 46 2 101 (2686-III) No 554 226 94 59 408 198 87 54 30 31 3 101 (2682-III) Yes 136 60 26 25 96 60 24 20 30 30 4 111 (2690-III) Yes 64 36 21 19 64 40 21 21 24 25 5 116 (2697-III) Yes 64 40 21 18 72 40 24 21 26 25 6 121 (2698-III) Yes 64 40 22 20 72 40 22 20 23 22 The gel strengths in toluene are somewhat analogous to the styrene swells. In the latter case as well a high degree of overtreatment results in inferior effects. It is felt that the hydrocarbon swelling and gelling activity of completely or overreacted clays is inferior to those only substantially reacted. A similar behaviour of ammonium clays towards nitrobenzene was reported by Jordan with a comment of overtreating being deleterious.

EXAMPLE 5.

Gelling Effectiveness of Dihydrogenated Ditallow Dimethyl Ammonium Montmorillonite Clays in an Unsaturated Polyester as a Function of Their Degree of Overtreatment.

The gelling effectiveness of various Astratone 40 type clays in a maleic and phthalic anhydride plus propylene glycol based unsaturated polyester was examined via the styrene pregel method described earlier. This unsaturated polyester is most often used for the preparation of glass reinforced thermoset resins. In the present tests, the final gels contained 40% styrene which serves both as a solvent for the solid polyester and a crosslinking monomer.

The gel resulting from the experiments using variously overtreated gellants were evaluated for their viscosity at 6 and 60 rpm. The viscosity data obtained and the viscosity indices are shown in Table V.

The preparation of the series of increasingly overtreated dihydrogenated ditallow ammonium montmorillonite gellants used was described in Example 2. The nonovertreated Astratone 40 commercial control gellant of 90 me treatment level was also described previously.

TABLE V VISCOSITY CHARACTERISTICS OF AN UNSATURATED POLYESTER-STYRENE RESIN CONTAINING 1.5% OF VARIOUSLY OVERTREATED DITALLOW DIMETHYL AMMONIUM CLAYS Brookfield Viscosities, cps. Viscosity Ratios (At various stirring rates, rpm) (6 per 60 rpm) Seq. Exp. No. Treatment, After 15 Min. After 18-24 Hr. After After No. E- me (6) (60) (6) (60) 15 Min. 18-24 Hr.

1 2811-I 1400 680 1420 702 2.05 2.02 90(a) 2 2682-III 99 1800 766 1860 770 2.35 2.42 3 2690-III 110 2200 858 2220 2.59 2.58 862 4 2697-III 115 2100 822 2140 830 2.55 2.58 5 2698-III 120 1720 694 1840 740 2.48 2.49 (a) Astratone 40, commercial clay.

The data of table IV show that the clay commercial gellant (Sequence No. 1) was generally less effective both in terms of absolute viscosities and viscosity indices than the overtreated clays (Sequence Nos. 26). The thixotropic effectiveness of the ex perimental clays was clearly dependent on their treatment level. The relatively poor performance of the commercial clay was obviously a consequence of its low treatment level.

The optimum treatment level was in the range of 110-115 milliequivalent di methyl ditallo ammonium chloride per 100 g dry clay (Sequence Nos. 3, 4). A com parison of the viscosity values of the commercial clay with the optimally treated clay shows rounded 60 rpm viscosities of about 1500 versus 2000 and viscosity indices of 2.0 versus 2.6. The better performance of the optimally overtreated clay seems parti cularly important in terms of the thixotropic index, which is the most important para meter in reinforced plastics applications.

The value of overtreatment in terms of the ammonium clay gellant needed to achieve certain thixotropic properties can be estimated from the response of the un saturated polyester resin to different concentrations of the normal Astratone 40 gellant (E-28 11-1). This concentration response is shown by the following tabulation.

Brookfield Viscosities, cps (At various Stirring Rates, rpm) Viscosity Ratios (At various Stirring Rates,I rpm, (6 per 60 rpm) Concentration of After 15 Min. After 18-24 Hrs.

Astratone 40 After After Geliant % (6) (60) (6) (60) 15 Min. 18-24 Hr

Micro-penetration values are then obtained at 25H-1 C. with a straight taper cone according to ASTM D 1403-69. The straight taper cone modification of the test is described in "The Lubrication Engineer's Manual ", edited by C. A. Bailey and J. S.

Aarons, published by United States Steel Corporation (1966). The results are shown in Table VI.

TABLE VI GELLING OF POLYDECENE BASE FLUID (a) BY 11% OF AN OVERTREATED AND NORMALLY TREATED AMMONIUM CLAY AS MEASURED IN A PENETRATION TEST (b) Quaternary Level, Micro- Full Scale Seq. Clay Exp. No. Quaternary me per Penetration, Penetration, No. - E- Cation Structure 100 g. clay mm x 0.1 mm x 0.1 12811-I (c) (C,8H37)2N+(CH3)2(d) 90 152 Too soft 2 2690will (e) (C18H37)2N+(CH,)2(d) 110 60 284 (a) Polydecene, ESH 400 from Ethyl Corp., having a viscosity of 19 centistokes at 10001 and about 10 olefin units per molecule.

(b) Micropenetration test according to ASTM D 1403-69 using a cone with a modified tip Full scale penetration test according to ASTM D 217.

(c) Georgia Kaolin's product, Astratone 40.

(d) Dimethyl ditallow ammonium group derived from the technical chloride salt, Adogen 440 of the Ashland Oil Co.

(e) Derived from the same Wyoming sodium montmorillonite as Astratone 40.

A comparison of the penetration data of Table I shows that in contrast to the normally treated clay the overtreated clay provided a hard polydecene grease.

A comparison of the gelling effectiveness of the overtreated and normally treated ammonium clay was also made in a solvent extracted high viscosity mineral lubricating oil base. This mineral oil contained only 11.1% paraffins. In addition, it had a 57.3% naphthenes, 29.1 % aromatic hydrocarbons and 2.4% polar non-hydrocarbon compounds.

Grease compositions based on the above mineral oil and the two clays were pre pared again on an 11% gellant basis. Micropenetration values were determined. The comparative results are shown by the following tabulation: Quaternary Level, me Micropenetration per 100 g. Clay mx 0.1 90 49 100 83 The data show that, in contrast to the results in polydecene, the commercial type clay of equivalent treatment level was a much more effective gellant in the mineral oil.

EXAMPLE 7.

Gelling of Polydecene by Overtreated Dimethyl Dihydrogenated Ditallow Ammonium Montmorillonite Clay in the Presence of Various Antioxidants.

Into a 250 ml. beaker are weighed 15.0 g. of oil base and 6.3 g. of organo clay.

After mixing the clay into the oil base with a flat tipped spatula, 0.38 g. of polar addi tive (propylene carbonate or acetone) is added with continued mixing. Meanwhile, 0.57 g. of antioxidant is dissolved in 35.02 g. of oil based by heating the oil at 60"C. in a water bath. The oil portion containing the antioxidant is allowed to cool to room temperature and is mixed with the other portion. Finally, 0.30 g. of water is added with continued mixing with a flat tipped spatula. The grease composition is then either heated and worked as described in the previous example or handled according to a modified procedure as follows: In a modification of the micropenetration test, the final grease composition is transferred into a crystallising dish (12.5 x 6.5 cm) and distributed evenly over the bottom and sides of the dish. The dish is then placed in a vacuum oven (i=1.0 mm) at 60 C for 30 mins. to remove the water and acetone. The grease is allowed to cool and worked through a 3-roll mill at a 0.9 setting.

Micropenetration values are obtained in the same manner as usual. The data of the greases prepared by both the regular and modified method are shown in Table VII.

The data show that all three types of additives could be used in the present greases without any large effect on grease hardness. The use of the hindered phenol had no adverse effect on the gel at all. The small adverse effect of the amines could be counter acted by an increased concentration of the clay gellant. The preferred polar additive was propylene carbonate.

TABLE VII GEI < IyING OF POLYDECENE BASE FLUID BY OVERTREATED AMMONIUM CLAY a IN THE PRESENCE OF VARIOUS ANTIOXIDANTS AS MEASURED IN A MICROPENETRATION TEST (b) Micropenetration (c), mm x 0.1 in the Presence of Antioxidant Added, 1% Clay Seq. Gelled Propylene Naphth 1 Diphenyl Hindered o. % Carbonate Acetone Amine td) Amine (e) Diphenol (f) 1 11 Yes - 90 80 (77g) 69 (57g) 2 13 Yes - 58 59 (62g) 47 (62g' 3 11 - Yes 78 75 63 (a) Sodium montmorillonite treated with 110 me per 100 g. clay of dimethyl dihydro genated ditallow ammonium chloride as in Table I.

(b) Micropenetration test according to ASTM D 1403-69.

(c) Most of the test procedures controlled the temperature of the removal of polar dispersants by the modified procedure.

(d) Phenyl-2-naphthyl amine.

(e) Bis, -4-isooctylphenyl-amine, Vanlube 81.

(f) 4,4'Methylene-bis-(2,6-di-t-butyl phenol) Ethyl 702.

(g) Original dispersant removal procedure, producing scattered results.

Claims (22)

WHAT WE CLAIM IS:

1. A quaternary C8 to C dialkyl dimethyl ammonium clay gellant of layer and chain type structure characterized by containing ammonium ions in a concentration ranging from 12 to 25% above the ion exchange capacity of the clay as expressed in milliequivalents per 100 g. dry clay wherein the ion exchange capacity is determined by the amount of ammonium acetate which reacts with the clay when an excess of ammonium acetate is used as a reactant.

2. A clay gellant according to claim 1 which comprises a quaternary dihydrogenated ditallow dimethyl ammonium montmorillonite clay gellant.

3. A clay gellant according to either of claims 1 and 2 characterized by containing ammonium ions in a concentration ranging from 15 to 20% above the ion exchange capacity of the clay.

4. A clay gelant according to any one of the preceding claims wherein the clay is a three layered type.

5. A process for preparing a quaternary C8 to C3 dialkyl dimethyl ammonium clay gellant of layer and chain type structure which comprises reacting in a reaction medium comprising water and a water miscible polar organic solvent a mineral clay of layer and chain type structure disposed in the mdeium with a quaternary C8 to C3, dialkyl dimethyl ammonium salt dissolved in the medium, wherein the concentration of ammonium ions of said ammonium salt ranges from 12 to 25% above the ion exchange capacity of the clay as expressed in milliequivalents per 100 g. dry clay and as determined by the amount of ammonium acetate which reacts with the clay when an excess of ammonium acetate is used as a reactant.

6. A process according to claim 5 wherein the concentration of the ammonium ions ranges from 15 to 20% above the ion exchange capacity of the clay.

7. A process according to either of claims 5 and 6 wherein the dialkyl substituent of the quaternary C8 to Cas dialkyl dimethyl ammonium salt is C18 to C18 alkyl.

8. A process according to any one of the claims 5 to 7 wherein the polar organic solvent is a C1 to C12 alcohol, ketone, ether, nitrile, sulphone, carboxylic acid, carboxylic ester or amide.

9. A process according to claim 8 wherein the polar organic solvent is isopropanol.

10. A process according to any one of claims 5 to 9 wherein the solvent to water ratio ranges from 1:20 to 2:1.

11. A process according to any one of claims 5 to 10 wherein the mineral clay dispersed in solvent and water comprises a Wyoming montmorillonite clay with a dihydrogenated ditallow dimethyl ammonium chloride.

12. A quaternary C8 to Cy, dialkyl dimethyl ammonium clay gellant of layer and chain type structure whenever prepared by the process according to any one of claims 5 to 11.

13. A composition comprising (1) a major proportion by weight of an oxygenated compound or a polyolefin and (2) a clay gellant according to any one of claims 1 to 4 and 12; said gellant being present in amounts sufficient to attain the desired thixotropic characteristics.

14. A composition according to claim 13 wherein the oxygenated compound is an alkyd type polyester.

15. A composition according to claim 13 wherein the oxygenated compound is an unsaturated polyester.

16. A composition according to claim 13 in the form of a grease comprising: (a) a major proportion by weight of a polyolefin lubricant base fluid; and (b) a minor proportion by weight of the clay gellant.

17. A composition according to claim 16 wherein the polyolefin is hydrogenated to provide a completely saturated aliphatic hydrocarbon.

18. A composition according to claim 16 wherein the polyolefin is a C8 to C12 polyolefin.

19. A composition according to claim 16 wherein the polyolefin is a hydrogenated polydecene lubricant base fluid.

20. A clay gellant according to claim 1 substantially as hereinbefore described with reference to the Examples.

21. A process for preparing a clay gellant according to claim 5 substantially as hereinbefore described with reference to the Examples.

22. A composition according to claim 13 substantially as hereinbefore described with reference to the Examples.