COMPOSITION FOR ALTERING RHEOLOGICAL PROPERTIES

Abstract: Compositions useful as rheological and/or thixotropic agents capable of altering or modifying the rheological characteristics of a system in which they have been incorporated. The compositions appear to result from the electromagnetic and/or electrochemical interaction of a clay, a quaternary ammonium compound and a compound containing Zirconium or a compound containing Silicon. The compositions are useful in altering and, particularly, controlling the rheological properties of plastic-type systems where such plastic-type systems are found in liquid, semi-solid or gel states as well as in coating systems.

Description: DESCRIPTION COMPOSITION FOR ALTERING RHEOLOGICAL PROPERTIES TECHNICAL FIELD OF INVENTION The present invention provides compositions related to the improvement in rheological characteristics of systems in which the compositions are incorporated. Presently, commercial examples of such systems are typically plastic-type systems or coating systems which will be more specifically defined hereinafter. Representative examples of prior art plastic-type systems include fiberglass or polyester resin/styrene polymers where such plastic-type systems can be in a liquid, semi-solid or gel form. Representative examples of coating systems include paints or laminating systems used in association with plastic-type systems which have become static such as fiberglass. z BACKGROUND ART Compositions within the scope of the present invention are easily adapted to and can be incorporated into many final end products and systems without the necessity of retooling a manufacturing facility. Heretofore desired rheological properties have been achieved through the use of commerically available materials well known in the art which are capable or modifying rheologial properties in varying degrees. One such agent is Fumed Silica- which is the most widely used agent in the art to date. Fumed silica is an entirely different chemical composition than those compositions within the scope of the present invention. However, there are disadvantages in the use of fumed silica as a rheological agent. One obvious disadvantage is that fumed silica has extremely low bulk density so the volume storage requirements are high. Further, because of such low bulk density it becomes difficult to incorporate the material into many plastic-type systems. Fumed silica is also extremely dusty and requires users to wear protective respiratory masks. Still another disadvantage is that fumed silica is expensive compared to compositions within the scope of the present invention and greater labor costs are associated with incorporating it in plastic-type systems. Another type of rheological agent for plastic-type systems is composed in part of organoclays. These organoclays are also known in the art as organophillic clays. Many of the processes for activating and making organoclay-rheological agents are described, defined and known in the related prior art which, insofar as known, includes U.S. Patent No. 4,569,923, U.S. Patent No. 3,977,894, U.S. Patent No. 4,391,637 and United Kingdom Application No. GB 2,158,053 A. These references disclose various processes of making rheological agents composed in part of an organoclay. The above noted references teach that a quaternary ammonium having varied carbon side chain groups extending from the Nitrogen atom are necessary to activate the surface of the clay that will eventually be incorporated into plastic-type systems. Further, the prior art describes that the organophillic clay requires a smectite-type clay base and that rheological agents containing smectite-type clay can be incorporated into aqueous or non-aqueous plastic-type systems. There are various suppliers of the above-described organoclay-rheological agents, examples of which are, Claytone PS™ available from Southern Clay Products and Polytrope 1131 from N.L. Chemicals. A major problem encountered with commercially available organoclay-rheological agents is that they do not enhance the thixotropic index of plastic-type systems to the level required by many producers of such plastic-type systems into which they are incorporated. Additionally, the organoclay rheological agents described in the prior-art must first be incorporated into a gel-like carrier before such agents can be incorporated into a plastic-type systems. Of course, this additional step adds additional cost to the use of the organoclay rheological agents already known in the art. Accordingly, in many cases, use of the organoclays provided by the prior art becomes impractical, if not prohibitive. Thus, to date, fumed silica remains the primary rheological agent used in plastic-type systems. DISCLOSURE OF THE INVENTION Compositions within the scope of the present invention are useful for altering the rheological c properties of plastic-type systems or coating systems. Within the scope of the present invention, plastic-type systems are defined as those systems comprised of polymers in a liquid state or a semi-solid state or a gel state which with the passage of time become static, hardened or solid. Typically, such o ' plastic-type systems can be represented by fiberglass, polyester or polyester/styrene systems. The improved rheological characteristics associated with plastic-type systems created by the incorporation of compositions within the scope of the present invention allow greater flexibility in shaping the final static or hardened end product produced by such plastic-type systems. A few examples of such end products include boats, bodies for automobiles, hard hats, casings for telephones, typewriters, computers, etc. Coating systems are those systems comprised of paints and/or laminating systems to provide protective outer coatings to static bases. Compositions within the scope of the present invention have been found to be less expensive to incorporate into plastic-type systems than other rheological agents presently known and/or those already commercially available. In addition it has been found that compositions within the scope of the present invention greatly improve the desired rheological characteristics of the plastic-type systems into which they are incorporated over other types of rheological agents, as will be disclosed more fully hereinafter. Compositions of the present invention typically include a smetite clay, a quaternary ammonium compound or mixture of various quaternary ammonium compounds and a compound containing at least one Zirconium atom or a compound containing at least one Silicon atom,in combination. The present invention include processes and materials to promote the interaction of an organophillic clay with either a compound containing the element Zirconium or a compound containing the element Silicon. This combination has heretobefore been unknown in the art for the purposes described hereinafter. Briefly the present invention provides compositions useful as rheological agents capable of altering or modifying the rheological characteristics of a system in which they have been incorporated. The compositions are the result of the electromagnetic and/or electrochemical interaction of a clay, a quaternary ammonium compound and a compound containing Zirconium or a compound containing Silicon. The compositions are useful in controlling the rheological properties of plastic-type systems where such plastic-type systems are found in liquid, semi-solid or gel states as well as in coating systems. BEST MODE FOR CARRYING OUT THE INVENTION The new and useful effects of compositions in accordance with the present invention have been discovered and demonstrated in various experimental 5 methods. As previously disclosed, compositions in accordance with the present invention are the result of the co binaton of a clay, a quaternary ammonium αompound, or mixture of quaternary ammonium compounds, and either a compound containing Zirconium or a compound containing Silicon. The electromagnectic or electrochemical forces responsible for the interaction of the Zirconium or Silicon compounds with the surface of the organophillic clay appear to be covalent ' banding. It has been found that compositions within the scape of the present invention unexpectedly and favorably alter the rheological properties of systems frrfcσ which they have been incorporated. Examples of sich systems include plastic-type systems and coating systems as hereinbefore defined. Compositions within the scope of the present invention are useful as rheological agents when incorporated in plastic-type systems or coating systems and, as such, the compositions provide high viscosity at low sheer rates to enhance the rheological properties of such systems. In other words, because of high viscosity and low shear rate provided by the incorporation of compositions within the scope of the 5 present invention into such systems, plastic-type systems will have greater propensity to retain their molded form until the plastic-type system has become static; and coating systems, such as paints are easily applied to surfaces without resultant sagging or slumping. 20 Methods by which organophillic clays are prepared are well known in the art. Thus, under appropriate conditions, an organic cationic compound such as a quarternary ammonium will react by ion-exchange with " the clay having a negative layer lattice and 15 exchangable cations to form an organophillic clay. Due to this phenomenon the clay becomes activated; therefore, it will electromagnectically or electrochemically interact with either a Zirconium compound or a Silicon compound in accordance with the present invention. 20. Clays within the scope of the present invention are smecite-type clays having a cation exchange capacity of at least 75 milliequivalents per 100 grams of clay. There are many commercially available quarternary ammonium compounds which will activate -5. smecite-type clays. After the clay has been activated either a Zirconium compound or a Silicon compound is introduced to the combination, and it has been found within the scope of the present invention that the activated clay and the Zirconium compound or the Silicon compound interact as hereinbefore described creating compositions in accordance with the present invention. The method of forming inventions within the scope of the present invention can be illustrated in weight to weight percentages as follows. A 3.2% to 3.5% clay slurry in water is made. The clay slurry is then filtered to remove any impurities, such as sand or gravel, thus, the clay is cleaned. A 2.0% to 3.0% slurry of the cleaned clay in water is then made which is then mixed and reacted with a 7.0% to 8.0% water emulsion containing the quatenary ammonium or a mixture of quatenary ammounium compounds. The quaternary ammounium compound or compounds activate the clay causing the clay to become organophillic. The organophillic clay is then mixed and reacted with 1.0% to 2.0% of either a Zirconium or a Silicon compound within the scope of the present invention. After the organophillic clay has reacted with either the Zirconium or Silicon compound in accordance with the present invention, the excess water can be removed by filitration and the resultant solids can be dried. Additionally, castor oil compounds may be incorporated into the dried solids in accordance with the present invention, thus, allowing greater flexibility in the control of the plastic-type or coating systems rheology in which the present invention has been incorporated. It is believed that the functional portion of Zirconium compounds within the scope of the present invention can be represented by the following general formula: R, / Al 'Zr where the Aluminum and Zirconium atoms are bonded to other molecular structures (not shown in the general formula for the Zirconium compound) . R, is respresentative of either a carboxylic acid group or an aromatic group containing at least six Carbon atoms or an alkyl group of the general formula (CH_) CH-.. More specifically, it has been found that when R, represents an alkyl group, the alkyl group contains less than 16 Carbon atoms. Regardless whether R, is representive of a carboxyl group including acids, an aromatic group or an alkyl group, it has been found that under laboratory conditions the resultant rheological properties of compositions within the scope of the present invention were generally the same. Various carboxylic acid groups containing up to five Carbon atoms were tested and it was found that C-H--C00r_ provided optimal rheological properties, for compositions within the scope of the present invention when R, is represented by a carboxylic acid group when a "pre-gel" (as will be described more fully 0 hereinafter) method of incorporation was used. Numerous aromatic groups containing at least six Carbon atoms with various hydrocarbon side-chains extending therefrom were tested and it was found that r C fi H _ι P rov "i ed optimal rheological properties, for compositions in accordance with the present invention when R- is represented by an aromatic group when a "direct add" (as will be described more fully hereinafter) method of incorporation was utilized. Because of acquisition costs, with the various o groups representing R, for the Zirconium compounds, the experimental data following hereinafter, will focus on Zirconium compounds where R, is C-H,COOH. It has also been found that Silicon compounds can also be used within the scope of the present invention 5 and can be represented by the general formula: R, f 2 R 5 Si__R 3 5 4 It appears that the Silicon compounds also interact with the organophillic clay by covalent bonding, however; other electromagnectic or electrochemical forces may be involved. R„, R_. or R. may be represented by a hydroxyl group or groups represented _U_ by the formula -O-RΛ or any combination thereof. For the purposes of the Silicon compounds, in accordance with the present invention where R„, R, or Rf.t represents -O-R_?_. the Oxygen molecule is -, ς bonded to a, Silicon atom and R . R represents an alkyl group including from two to four Carbon atoms. Because of acquisition costs, with the various R groups associated with the Silicon compounds in accordance with the present invention, the data which follows hereinafter will concentrate on the following o composition within the scope of the present invention having the following formula: ι 2 5 H 5 C 6- Si •OC 2 H 5 OC 2 H 5 Regardless whether Zirconium or Silicon compounds were incorporated into compositions within the scope of the present invention, laboratory data indicates that present compositions are more compatable with, and provide better rheological properties for the systems in which they are incorporated, than the organoclay rheological agents heretobefore disclosed. Further, it has been found.that compositions of the present invention can be incorporated into a system without the use of a gel-like carrier as required by the rheological agents presently known. However, compositions within the scope of the present invention may be incorporated into systems with the use of a gel-like carrier. As previously disclosed, after either the Zirconium or Silicon compounds are reacted in combination with the previously described clay and quarternary ammonium compound or compounds, the composition is dried. The compositions are thereafter ready to be incorporated into systems such as a plastic-type systems or coating systems as hereinbefore defined. Additionally, in accordance with another feature of the present compositions, it has been discovered that the addition of castor oil compounds in concentrations of up to 25% by weight of the composition will further advantageously alter the rheological properties of the plastic-type system into which the composition is incorporated. Compositions of the present invention are compatible with many plastic-type systems and/or coating systems and may be incorporated into such systems in concentrations from 0.10%-2.00% by weight of such systems. It is well known in the art that rheological agents are generally incorporated into plastic-type systems and/or coating systems by either of two methods. Those methods are known as the "pre-gel" or "direct add" methods. The "pre-gel" method can be described as the addition of the rheological agent into a gel-like carrier which is thereafter incorporated into a system. The "direct add" method is self explanatory in that the rheological agent is incorporated directly into the system without the necessity of a gel-like carrier. It has unexpectedly been found that compositions within the scope of the present invention may successfully be incorporated into systems by either the "pre-gel" or "direct add" methods. Other presently known organoclay rheological agents can only be incorporated into systems via the "pre-gel" method, otherwise, such organoclay rheological agents separate from such systems and fail to yield meaningful modification to such systems rheology. In the industry the rheological properties of systems hereinbefore described and the effectiveness of thixotropic agents incorporated into such systems can ultimately be evaluated by the "drain out" test. The "drain out" test, stated simply, is a quantitative measurement of the ability of a system to retain its form or shape until such system has become static. More specifically,- "drain out" can be described as the percentage of surface area of a glass matting, such as fiberglass, from which the system has drained because of gravity with such percentage being measured as a function of time. The "drain out" tests for compositions within the scope of the present invention were conducted using the following procedure. The various rheological agents of the present invention were incorporated into a system in a ratio of 1.0% by weight of the system. Five grams of this material was poured onto a 3" x 5" glass matting and immediately worked into the matting with a spiral laminating roller suitable for fiberglass lay-up work until the air is removed. The matting is then placed at a 75° angle and observed at 1, 2, 3, 4, and 5 hours. Various compositions in accordance with the present invention were measured using the "drain out" testing procedure. Claytone PS ™ and Fumed Silica as previously discussed herein were also used as rheologcial agents for the purposes of comparison. The system into which the above rheological agents were incorporated was a polyester-styrene mixture for the purposes of obtaining "drain out" data. The data and graphs which follow summarize "separation" and "drain out" data for the specific compositions in accordance with the present invention as indicated therein in comparision with Claytone PS ™ and fumed silica. SEPARATION TEST ZR Claytone PS™ Fumed Silica Time 1 hr 0.00% 0.00% 0.00% 24 hrs 0.00% 81.00% 92.00% 48hrs 0.00% 70.00% 90.00% SI Claytone PS™ Fumed Silica Time lhr 0.00% 0.00% 0.00% 24hrs 0.00% 10.00% 96.00% 48hrs 0.00% 10.00% 96.00% All "separation" Tests were performed as follows: 1.00% w/v of the rheological agent was added to identical volumes of carrier thereafter the rheological agent was completly dispersed in the carrier, i.e. plastic type system. The carrier was 8141 resin manufactured by Cargill, Inc. Percentage figures represent the ratio of settled rheological agent height to total system height, i.e. the amount of rheological agent that has settled out of the carrier do to the force of gravity as a function of time. ZR represents the Zirconium compounds in accordance with the present invention having the following functional portion: Al' 'Zr SI represents the Silicon Compounds within the scope of the present invention having the following formula: DRAIN OUT GRAPHS Pfircr.nl πrniπ-()ut IVπ. il. Urn iιι-()ιιt 25 ZR and SI represent the same compounds as previously identified. CO represents Claytone PS™. FS represents Fumed Silica. The results of the "separation" and "drain out" tests clearly indicate the superiority of compositions within the scope of the present invention in relation to rheological agents presently known with respect to their ability to alter the rheology of a system into which they have been incorporated.

Claims: CLAIMS : 1. A--composition for altering the rheological ^ properties of a system in which said composition is incorporated, comprising: a) a clay; b) a first compound containing a quaternary ammonium compound or a mixture of quaternary ammonium compounds and, 0 c) a second compound containing at least one atom of the element Zirconium. 2. The composition of Claim 1 wherein said clay is a 5 smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay. 3. The composition of Claim 1 wherein said second 0 compound also contains at least one atom of the element Aluminψn.. The composition, of Claim 3, further comprising: 5 f 1 0 C 1 - __ 0 a) wherein R, is a carboxylic acid group containing less than five Carbon atoms, or; b) wherein R, is an aromatic hydrocarbon containing at least six carbon atoms, or; c) wherein R, is an alkyl group containing less than sixteen Carbon atoms. 5. The composition of Claim 4 wherein said carboxylic acid group is C-H.-C00H. 6. The composition of Claim 4 wherein said aromatic hydrocarbon is CgH.. 7. The composition of Claim 1 further comprising, a castor oil compound added to said composition in concentrations of up to 25% by weight of said composition. 8. The composition of Claim 7 wherein, said castor oil compound is hydrogenated castor oil. 9. A composition for altering the rheological properties of a system in which said composition is incorporated, comprising: a) a clay; b) a first compound containing a quaternary ammonium compound or a mixture of quaternary ammonium compounds; and, c) a third compound containing at least one atom of the element Silicon. 10. The composition of Claim 9 wherein said clay is a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay. 11. The composition of Claim 9, further comprising: R a) wherein R 2 is either a hydroxyl group or a group having the general formula of O-R ; b) wherein R-, is either a hydroxyl group or a group having the general formula of O-R, ; c) wherein R. is either a hydroxyl group or a group having the general formula of O-R ; and, d) wherein R 5-. is C6-H5-.. 12, The composition of Claim 11 wherein said R , said R,b and said Rc contain at least 1 atom of the element Carbon. 13. The composition of Claim 12 wherein said R is C2 0 H5 r , said R,b is C2-.H5- and said Rc is C 2 H 5 . 14. The composition of Claim 9 further comprising, a castor oil compound added to said composition in concentrations of up to 25% by weight of said composition. The composition of Claim 14 wherein, said castor ompound is hydrogenated castor oil.

Inventors: ELLIOTT DONALD R, ELLIOTT, DONALD, R.
Applicants: UNITED CATALYSTS INC, UNITED CATALYSTS INC.
Application year: 1988
Main classification: C04B33
IPC codes: C01B33, C08K3, C08K5, C09D5