MXPA99008577A - Reticulated bacterial cellulose as a rheological modifier for polyol fluid compositions - Google Patents

Abstract

Rheologically modified compositions, and rheologically modified fluid compositions prepared therefrom, containing reticulated bacterial cellulose in a polyol base fluid, are disclosed. The amount of reticulated bacterial cellulose present in the composition is an amount effective to viscosify the polyol base fluid.

Description

BACTERIAL CELLULOSE REJECTED AS A REOLÓGICO MODIFIER FOR POLYOL FLUID COMPOSITIONS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to rheologically modified polyol compositions, which use crosslinked bacterial cellulose as a rheology modifying agent.

THE BACKGROUND TECHNIQUE The rheologically modified polyol compositions, or those to which viscosity has been imparted, have many uses. They have been used for fluid seal / retention systems, for example, as tire sealants, fluid impellers and the like. Polyols, and in particular polyethylene glycols, are frequently added, together with other components, for various applications in cosmetics, for example, cast bars (lipstick), sunscreens, astringents, shaving products, including gels and creams for before shaving and shaving, and after-shave products. Polyols are common additives in other personal care products, such as fixatives, dyes and hair conditioners, and are often used as vehicle providers of treatments for the scalp. In each of these applications, the combination of polyols with a rheological modifying agent forms compositions that have become viscous, giving products that are easy to use and apply. Rheologically modified polyols provide improved flow properties and adhesion to various humectants, such as toothpastes and gels. Synthetic lubricants represent yet another application in which the increased rheology of the base polyol fluids receive adhesion and release control and prevent the leakage flow of the lubricant. Due to the ability of the rheologically modified polyols to suspend particles, those viscous compositions can be used as fluid delivery compositions or as carriers for certain materials. Fluids for working metals containing said rheologically modified polyols can be used as auxiliaries to transport the cuttings. Additionally, those fluid compositions can be used as carriers or as delivery vehicles for other particulate materials, for example, water-soluble hydrocolloids. These aspects of supply and adhesion to surfaces are important in other applications as well, such as in varnish and paint removers and in other paint applications. The rheologically modified polyols have been used in oilfield operations, for example, in drilling fluids, in complement / completion fluids, cement fluids, oil well insulator fluids, as ballast materials, base hydraulic fluids without petroleum and similar. The transportation of oil obtained from fields located offshore requires systems with special design. Sometimes the temperature of the oil, pumped from below the bottom of the ocean, is approximately 104-121 ° C, but the temperature of the water through it must be transported so that the oil can be so low that it reaches 0-10 ° C. Any system for transporting oil through such an environment at low temperature must provide an adequate means to isolate the oil from the low temperature of the circulating environment. Failure to provide adequate insulation results in a reduction in oil temperature. It is important to keep the temperature of the oil high so that it retains its low viscosity and its possibility of pumping, when pumping oil through the pipeline. As the temperature decreases, the viscosity of the oil increases, making pumping difficult. Additionally, at lower temperatures, the result may be that various fractions of hydrocarbon present in the oil separate and crystallize. For example, paraffins can be deposited, low viscosity hydrocarbons, medium viscosity hydrocarbons, oil sludge and the like, on the walls of the pipeline, gradually restricting the oil flow. Thus, the means of transport, typically pipelines, must be isolated to achieve an efficient oil flow. Ramsay and co-authors, in US Pat. No. 5,290,768, describe the use of rheologically modified welan / ethylene glycol compositions as insulating fluids for oil pipelines. A chelating agent, such as ethylenediaminetetraacetic acid, is present in these compositions to minimize the deleterious effects of metal ion contaminants present in pumping operations in the pipeline. However, a rheologically modified, improved composition, which would serve as a thermal insulating material, which would have very durable stability at high temperatures and in the presence of metal ion contaminants, without the need for additional chelating agents, would be extremely convenient for oil isolation in the pipeline. The cross-linked bacterial cellulose is a useful and unique rheological modifier or viscosity imparting agent. In contrast to water-soluble viscosity imparting agents, such as various polysaccharide derivatives, guar gum, welan gum, xanthan gum and sodium alginate, crosslinked bacterial cellulose is a colloidal fiber lattice. of ultrafine cellulose. This lattice structure differentiates the cross-linked bacterial cellulose used in this invention from other polysaccharide derivatives. When the fine cellulose fibers of the cross-linked bacterial cellulose are dispersed in a base fluid, the colloidal network expands throughout the fluid. In this dispersed form, the crosslinked bacterial cellulose is insensitive to many of the rough conditions that adversely impact soluble polysaccharide materials, such as rough temperatures, pH, salinity and shear stress. As used herein, the term "cross-linked bacterial cellulose" refers to cellulose produced by microorganisms using aerobic culture techniques, and is characterized by a strongly cross-linked network, with interconnected branches, of fibers that are insoluble in water. The cross-linked bacterial cellulose can be produced by the genus Acetobacter, under agitated conditions, and is available, under the trademark Cellulon®, from NutraSweet Kelco Company, a unit of Monsanto Company, St. Louis, Missouri, USA. The preparation of bacterial cellulose Reticulated is well known. For example, U.S. Patent No. 5,079,162 and U.S. Patent No. 5,144,021, both incorporated herein by this reference, describe a method and means for aerobically producing cross-linked bacterial cellulose, under agitated culture conditions, using a bacterial Acetobacter aceti strain. , var. xylinum. The use of agitated culture conditions results in a sustained production, for an average of 70 hours, of at least 0.1 g / liter per hour of the desired cellulose. The cross-linked cellulose in wet cake, containing about 80-85% water, can be produced using the methods and conditions described in the patents mentioned above. The dried, cross-linked bacterial cellulose can be produced using drying techniques, such as spray drying, drum drying, tray drying or freeze drying, which are well known. Acetobacter is characteristically a gram-negative rod-shaped bacterium, 0.6 to 0.8 μm per 1.0-4 μm. It is a strictly aerobic organism; that is, his metabolism is respiratory, never fermentative. This bacterium is further distinguished by its ability to produce multiple poly-β-1,4-glucan chains, chemically identical to microcrystalline cellulose. The microcellulose chains, or microfibrils, of cross-linked bacterial cellulose, are synthesized on the bacterial surface, at sites outside the cell membrane. These microfibrils generally have dimensions, in cross section, of about 1.6 x 5.8 nm. Due to the small particle diameter, microfibrils have a surface area several orders of magnitude higher than normal wood cellulose. This extremely high surface area, which is responsible for many of the unique functional properties (viscosity, elastic limit, binding properties, etc.) of the crosslinked bacterial cellulose. The rheologically modified aqueous compositions containing crosslinked bacterial cellulose compositions have been used in petroleum production applications. U.S. Patent No. 5,009,797 discloses a high viscosity aqueous hydraulic fracturing fluid composed of a mixture of aqueous base, cross-linked bacterial cellulose and a gellant. Aqueous, interlaced fracturing fluids, which demonstrate increased resistance to weight loss with temperature and physical shear stress, have also been prepared using cross-linked bacterial cellulose, a gelling agent and an interlacing agent; see U.S. Patent 5,350,528. Methods for drilling formations, which use aqueous hole-hole drilling muds, which contain cross-linked bacterial cellulose, are described in US Pat. No. 5,362,713. The drilling muds may additionally contain water-soluble polymers, such as cellulose derivatives, polyacrylamides or other polysaccharides. Morano, in U.S. Patent 5,366,750, discloses non-aqueous, edible thermostable compositions containing cellulose materials with ultra-high surface, such as bacterial fermentation cellulose, which are pre-dried with a chaotropic agent, preferably corn syrup, for use as fillings or creams for food products. These compositions have extremely low aqueous activity and additionally contain a non-aqueous, edible hydrophilic liquid. However, there remains a strong need for stable, rheologically modified polyol compositions useful for industrial applications. These highly desirable compositions would possess good flow properties, which would allow them to be pumped and poured and would increase the value of current polyol applications.

BRIEF DESCRIPTION OF THE INVENTION This invention is directed to rheologically modified, stable and stable compositions containing crosslinked bacterial cellulose in a base polyol fluid. The amount of cross-linked bacterial cellulose present in the compositions is an amount effective to impart viscosity and stabilize the compositions, while allowing a smooth and uniform flow, which allows the compositions to be pumped and poured. The present invention is directed to rheologically modified polyol compositions, to fluid compositions prepared therefrom, and to methods for using such compositions as deicing agents, anti-peel agents or pour point enhancers, drilling fluids, fluid supply compositions , for example, fluids for supplying hydrocolloids, as well as drilling fluids and the like. The present invention is further directed to a method for using rheologically modified polyol compositions, as a thermal insulation composition, i.e., as an insulator in oil pipelines. The rheologically modified insulation composition of this invention is particularly suitable for maintaining a relatively high oil temperature during transportation within a pipe located in a relatively low temperature environment, such as seawater.

DETAILED DESCRIPTION OF THE INVENTION The rheologically modified poiyol compositions of this invention comprise versatile and stable dispersions of crosslinked bacterial cellulose and a base polyol fluid. The polyol compositions can be prepared by mixing the crosslinked bacterial cellulose with the base polyol fluid, to form a homogeneous dispersion. The dispersion of crosslinked bacterial cellulose in the polyol can be preferably carried out using high energy mixing conditions, for example, using high shear mixing or homogenization. The apparatus that may be useful for forming the cellulose dispersion includes a Gaulin homogenizer, a Waring blender or other high shear mixers, such as those manufactured by Silverson, Ross, Greaves and the like; or a Heidolph propeller mixer. The amount of crosslinked bacterial cellulose present in the polyol compositions is that amount necessary to effectively thicken the base polyol fluid, i.e., to impart viscosity to the base polyol fluid, at a desired viscosity, which may vary, depending on the intended use of the composition. These polyol compositions can be used directly or they can be used in combination with other additives to form rheologically modified fluid compositions. The rheologically modified compositions of this invention have advantageous stability and good flow properties, that is, good pumping characteristics. These compositions are also thixotropic and will liquefy when agitated, shaken or shaken, and then thickened upon standing. Preferred polyol compositions of this invention will form a gel structure when at rest. The cross-linked bacterial cellulose used to prepare the rheologically modified polyol compositions of this invention may be in the form of a culture medium (liquid or concentrated fiber), a wet cake or a powder; but it is preferred to use it as a solid, for example, a wet cake or a dry powder. While the amount of crosslinked bacterial cellulose present in the polyol compositions of this invention will vary, depending on the viscosity of the composition necessary for a speciuse, the amount of cellulose used is typically about 0.005% to 2.0% by weight of the composition. The polyol-based fluids, which can be used in the rheologically modified compositions of this invention, are polyhydroxyl-containing solvents, which contain 2 or more hydroxyl portions. Polyol-based fluids, examples, include, but are not limited to: glycols, for example, ethylene glycol, propylene glycol; polyglycols, for example, polyethylene glycol, polypropylene glycol; and polyhydric alcohols, for example, glycerin. These base fluids may be used alone or in combination with other solvents that are miscible with the base fluid, for example, water, lower alkyl alcohols or other polyols. Commercially available base polyol fluids often contain low amounts of impurities, including water. Typically, they contain less than 10% water and, preferably, less than 5% water, by weight.Consequently, these base polyol fluids are considered as substantially non-aqueous solvents; and the rheologically modified compositions, prepared from them, are considered as substantially non-aqueous, rheologically modified compositions. The total amount of fluid used in the rheologically modified polyol compositions of this invention will vary depending on the intended use of the composition. However, generally, the total amount of fluid in the polyol compositions of this invention is about 40% to about 99.995% by weight of the composition. The amount of base polyol fluid present in the polyol compositions of this invention is about 50% to 99.995% by weight of the total amount of fluid present in the composition and, preferably, about 95% to 99.9% by weight. weight of the total amount of fluid present in the composition. When dispersed in the base polyol fluid, the crosslinked bacterial cellulose provides a fine structure that is effective to create an elastic limit. The elastic limit is a measure of the force necessary to initiate the flow in a gel-like system, and represents the tension necessary to initiate the movement of the fluid. The elastic limit is indicative of the suspension capacity of a fluid. The yield strength obtained by the use of crosslinked bacterial cellulose, particularly in base polyol fluids, imparts excellent stability to a variety of industrial applications. When used to prepare a thermal insulation fluid, the fine lattice substructure formed by the crosslinked bacterial cellulose effectively prevents the formation and circulation of thermal convection currents. When used to prepare fluid carrier or delivery compositions, the fine lattice substructure increases the ability of the fluid to suspend particulate materials, such as hydrocolloid particles, metal trimmings and the like, and contributes to the formation of smooth suspensions, stable, of particles that do not sediment, not even at rest. The rheologically modified polyol compositions of this invention are useful for imparting improved adhesion and anti-release properties for de-icing fluids, especially for aircraft and other machinery that need to be kept free of ice buildup in freezing environments. The method of using a rheologically modified polyol composition as a de-icing fluid comprises applying the polyol composition by spraying, pouring or pumping it onto the surface of the object or substrate to be protected. The increased adhesion properties of the polyol composition substantially inhibit or prevent the composition from flowing out of the surface of the object, thereby forming a barrier between the surface of the object and the environment. In addition, when the object begins to move, that is, when an airplane begins to decorate and the force of the air increases against the plane, the thixotropic polyol composition liquefies and flows out of the object, thereby functioning as an efficient temporary coating. of the object. The rheologically modified fluid compositions of this invention contain the rheologically modified polyol composition of this invention, in combination with various additives that are typically present or are necessary or convenient for specific applications. Typical additives may include the active materials of the composition or stabilizing agents that are added to prevent degradation of the composition. Because the crosslinked bacterial cellulose is capable of maintaining high viscosity and stability in the rheologically modified compositions, in the presence of different types of additives, the compositions of this invention are advantageously useful for a wide variety of applications. further, because the crosslinked bacterial cellulose compositions remain stable, the compositions of this invention are useful without addition of the stabilizing agents necessary for many of the viscosity imparting agents of the prior art. In one embodiment of this invention, rheologically modified thermal insulation fluids can be prepared and used for the transport of a temperature-sensitive fluid, eg, oil, through a lower temperature environment surrounding the fluid sensitive to temperature. The fluid, thermally modified, rheology compositions of this invention contain bacterial cellulose crosslinked in a base polyol fluid and may optionally contain coagents, corrosion inhibitors and / or metal sequestrants (metal chelators). The rheologically modified thermal insulation composition of this invention can be used to isolate a thermally sensitive fluid, surrounding an outer surface of a fluid transport member, with the fluid composition. Generally a fluid transport member, such as a pipe or a set of pipes (bundle of pipes) is placed inside a carrier pipe. The carrier pipe has a diameter sufficiently larger than the fluid transport member to provide an insulating chamber. The introduction of the rheologically modified thermal insulation composition of this invention, in the insulating chamber, encircles or encloses the fluid transporting member to provide a stable and effective insulating system, which reduces the heat loss of the fluid during the operation of transportation (fluid pumping) through the fluid transport member, of an oil pipeline. This arrangement allows the fluid transport member to be effectively isolated from the lower temperature environment. The fluid sensitive to temperature, for which the method described above is especially useful, is petroleum, particularly oil that is obtained from oil wells on the sea floor. Said oil, which naturally has a higher temperature than the sea near the bottom of the ocean, is isolated from the lower temperature of the sea and retains its naturally high temperature, as it flows through the pipes to reach the oil collection facility , based on the surface of the ocean or on land. The insulating capacity of the fluid thermal insulation composition is such that it is possible to have larger lines on the seabed or lower production rates through shorter lines, while maintaining the minimum oil temperatures in the line final. The thermal insulation composition of this invention also helps ballast the bundles of tubes to substantially eliminate the buoyancy of the carrier tube that could occur with an alternative insulation system. Conventional insulation materials, such as extruded foams and insulation wraps, which are low density materials, do not provide such stability. Significantly, the thermal insulation composition of this invention is stable in the presence of cations. The cations can detrimentally impact the fluids imparted viscosity with anionic polysaccharides by interlacing with the viscosity imparting agent or the polysaccharide material. Steel or concrete pipes, used to contain the insulation composition, serve as sources for cationic contaminants. Steel tubes can introduce iron ions or other metal ions into the insulation composition. The concrete used in the pipes can introduce calcium ions into the fluid. The fluid, thermally modified, rheology compositions of the present invention are advantageously stable in the presence of metal ions, without the need for additional metal scavengers. Nevertheless, optionally, metal sequestrants (chelators) can be added to the thermal insulator composition of this invention to increase the stability of the composition. The rheologically modified insulation compositions of this invention possess other advantageous properties, such as a thermal insulation material for oil well. The crosslinked bacterial cellulose present in the base polyol fluid is compatible with water and with salt water. In addition, the miscibility of the base polyol fluid in the water ensures that there will be no lasting detrimental effects to the environment in case of spillage of the composition. The amount of cross-linked bacterial cellulose present in the rheologically modified thermal insulation composition of this invention is an amount effective to impart viscosity to the base polyol fluid to substantially reduce the convection flow in the composition. Typically, the amount of the cellulose present in the flowable composition is about 0.05% to 2% and, preferably, about 0.1% to 1% and, more preferably, about 0.4% to 0.7% by weight of the composition. The amount of base polyol fluid, present in the flowable composition, is about 50% to 99.995% and, more preferably, about 95% to 99.6% by weight of the composition. Optionally, coagents or dispersing agents can be used in the thermal insulation compositions of this invention, to provide for increased inhibition of convection current formation and / or to improve the pumping ability of the resulting mixtures. The coagents useful in the present invention are typically water-soluble polymers that are capable of interacting with the surface of the cross-linked bacterial cellulose, in a non-covalent manner (ie, by hydrogen bonding with cellulose). The coagents can be used to modify the flow behavior of the crosslinked bacterial cellulose dispersions, act as auxiliaries for the dispersion / activation process, of high energy, to improve the activation efficiency, to prevent the possibility of flocculation and sedimentation of cellulose, and to act as a dispersant and auxiliary reactivation for dry materials, produced from dispersions of crosslinked bacterial cellulose. Coagents can be added alone or in solution. Suitable coagents are water soluble cellulosic materials. Thus, the fluid thermal insulation compositions of the present invention may optionally contain sufficient amounts of water to solubilize the coagent in the base polyol fluid. Coagents that may be useful in the present invention include, but are not limited to: hydroxyethyl cellulose (HEC), cationic hydroxyethyl cellulose, methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroxymethyl cellulose (HMC), nonionic cellulose, hydroxypropyl cellulose (HPC), cellulose fiber (ie, Solka-Floc®, sold by James River Corp., Berlin, New Hampshire, USA), welan gum and xanthan gum. A preferred coagent is carboxymethylcellulose. If present, the amount of coagent used in the thermal insulation composition of this invention is about 0.05% to 1% and, preferably, about 0.05% to 0.25% by weight of the composition. Optionally, corrosion inhibitors can be present in the thermal insulation fluid of the present invention, to provide increased stability of the pipe / insulator system, inhibiting the deterioration of concrete or steel pipes, by constant contact with the composition of insulation fluid. Corrosion inhibitors are compounds or compositions that will adhere to the surface of the pipe, forming a protective coating on it. Corrosion inhibitors that may be useful include, but are not limited to: surfactants, for example, N-lauryl sarcosine (used as Hamposyl-O®), a product of W. R. Grace, Co.), triethanolamine, fatty diamines, phosphonates, acetylenic alcohols, polyoxyalkylated amines and polyoxyalkylated imidazolines. A preferred corrosion inhibitor is N-lauryl sarcosine. If present, the amount of corrosion inhibitor used in a thermal insulation composition of this invention is about 0.01% to 1% and, preferably, about 0.05% to 0.1% by weight of the composition. Optionally, metal sequestrants or metal chelators may be present in the thermal insulation fluid of the present invention to give increased stability to the pipe / insulator system, joining metal cations that may be present in the fluid insulation composition. Once attached to the chelator, additional reactions of the metal cation with other materials present in the isolation fluid are inhibited or prevented.

Accordingly, the compounds that are useful as metal sequestrants or chelators in the present invention are those compounds or compositions that form stable complexes with metal ions, and particularly with metal ions that are present in, or that could be generated from, materials used in the construction of the pipe. Examples of useful metal sequestrants (chelating agents) include, but are not limited to: polyphosphates, eg, pyrophosphate, metaphosphate; hydroxy acid salts, for example, sodium citrate, sodium gluconate; aminopolycarboxylic acids, for example, ethylenediaminetetraacetic acid, nitrilotriacetic acid, hexahydric alcohols, for example, sorbitol and mannitol. If present, the amount of metal scavenger used in a thermal insulation composition of this invention is about 0.05% to 1% and preferably about 0.05% to 0.2% by weight of the composition. The fluid, rheologically modified isolation compositions of this invention can be prepared by combining at least one of the above-described additives with the rheologically modified polyol composition of this invention. Optionally, coagents, corrosion inhibitors and / or metal scavengers can be added by mixing these net additives (such as solid or liquid powders) or in solution with the dispersed polyol composition. Alternatively, a coagent can be combined with the crosslinked bacterial cellulose, prior to dispersion, to obtain a well dispersed mixture of the coagent and the bacterial cellulose crosslinked in the polyol. Solutions of the additives can be prepared by dissolving the additive in water or in a base polyol fluid, depending on the solubility characteristics of the additive. The rheologically modified thermal insulation fluid composition of this invention preferably contains cross-linked bacterial cellulose, ethylene glycol or polyethylene glycol and carboxymethylcellulose or cationic hydroxyethylcellulose. More preferably, the fluid thermal insulation composition includes cross-linked bacterial cellulose, ethylene glycol and carboxymethylcellulose. Fluid delivery compositions constitute another embodiment of this invention. These delivery compositions contain particulate materials, or active materials, which are suspended, but not solvated, in the fluid and, thus, can be supplied or carried by the fluid. These delivery compositions are typically prepared by mixing the particulate material and any other necessary additive, with the rheologically modified polyol composition of this invention, described above. The base polyol fluids, useful in the hydrocolloid supplying fluid composition of this invention, are fluids that do not dissolve or solvate the hydrocolloid or other particulate materials that are to be supplied or carried. A base polyol fluid, especially useful, is polyethylene glycol (PEG). Preferred polyol base fluids are those polyethylene glycols obtainable commercially under the designation PEG 200, PEG 300, PEG 400 and the like. The compositions for fluid delivery, containing water-soluble hydrocolloids in admixture with the polyol composition of this invention, are useful for dosing hydrocolloids, ie, food starches, in food processing systems. Generally hydrocolloids are commercially available as dry powders, and accurate dosing of discrete amounts of said solid powders is often difficult. The formation of the stable, but fluid, viscous dispersions of the hydrocolloids in the rheologically modified polyol composition of the present invention allows the dosing of the hydrocolloids using a common liquid supply equipment, for example, the liquid supplying equipment in ready-to-use concrete mixing plants, and in the mixer truck equipment; the feeding systems in liquid processes, in food and industrial plants, and the like. The amount of cross-linked bacterial cellulose present in the fluid composition for supplying hydrocolloid, of this invention, is about 0.005% to 2.0% by weight of the composition, and preferably, 0.005% to 0.5% by weight. The amount of hydrocolloid particulate materials, present in the fluid supply compositions is about 0.1% to about 60% by weight of the composition. The amount of base polyol fluid used in the compositions for supplying fluid will vary significantly in these types of compositions, because the weight of the particulate material to be delivered in the fluid is specific to the application. The amount of base polyol fluid present in the composition will be that amount which is necessary to fluidize the cellulose / hydrocolloid mixture, at a desired viscosity. Accordingly, the amount of base polyol fluid used in these compositions can vary from about 40% to about 99.9% by weight of the composition. However, the base polyol fluid will constitute about 95% to 100% of the fluid used in the composition. In another embodiment of this invention the rheologically modified polyol composition can be used as the drilling fluid. Drilling fluids are used to clean and cool the drill bit during drilling operations. Typically, the drilling fluid is pumped through the drill bit to flood rock cuttings, eg rock particles and other detritus, out of the drill bit; and to suspend and transport the rock cuttings to the surface, thus improving the efficiency of the drilling. The amount of cross-linked bacterial cellulose present in the drilling fluid composition of this invention is about 0.005% to 2.0% by weight of the composition, and preferably 0.02% to 0.5% by weight of the composition. The amount of base polyol fluid present in the drilling fluid composition is about 90% to about 99.995% by weight of the composition. The rheologically modified polyol compositions of the present invention are useful for imparting enhanced properties to a wide variety of applications, in addition to those described hereinabove. For example, polyol compositions are useful for imparting adhesion and anti-peel properties to paint and varnish removers, to tire sealants, to shock absorbers, to fluid impellers, to metalworking fluids, to lubricants , cosmetics, personal care products and the like. For each application, a rheologically modified fluid composition, comprising a mixture of the polyol composition of this invention, having an appropriate viscosity for the specific application, and any additives, such as solvents that remove paint or materials, can be applied. Sealant formers, by spraying, pouring or pumping on the surface of the object to be coated. For example, a fluid composition, tire sealant, can be introduced into a tire to coat and seal the inner surface of the tire, while a fluid paint remover composition can be applied over the painted surface of a chair, a door or a object from which the paint will be removed. The increased adhesion and anti-peel properties of the fluid compositions substantially inhibit or prevent the compositions from flowing out of the surface of the object or subject that is coated with the composition. While various uses of the compositions of this invention and various compositions containing the polyol compositions of this invention have been described, this disclosure is not intended to limit the present invention.; and those skilled in the art can readily contemplate other applications of, and compositions containing, the polyol compositions of the present invention; all of which is considered within the scope of the present invention. The following examples are intended to be illustrative of some preferred embodiments of the invention, and a limitation to the invention is not implied.

EXAMPLE 1 COMPOSITION OF POLYOL Crosslinked bacterial cellulose was dispersed as a wet cake in polyethylene glycol (PEG 200) using a high speed (1200 r.p.m.) pulsating style mixer equipped with a disintegrating or saw blade type mixing blade. Mixing was continued until all the wet cake was visibly dispersed. The solution was further passed through an extension homogenizer, three times, at a pressure of 10.545 kPa. The used extension homogenizer was equipped with a 0.5 mm diameter nozzle at a separation distance of 0.25 mm. The unit contains a dispersion device including a nozzle and a plate having a defined spacing within which a fluid or a multi-component system is forced under pressure. The extension homogenizer is further described in International Publication No. WO 96/40423, the description of which is incorporated herein by reference. The pressure for this unit was supplied by compressed gas. The resulting fluid of crosslinked bacterial cellulose / polyethylene glycol was tested for viscosity at room temperature using a Brookfield DV3 viscometer equipped with a small sample adapter (spindle SC4-14) at 2.5 rpm. The concentration of crosslinked bacterial cellulose is given as a percentage by weight of the active material.

TABLE 1 EXAMPLE 2 INSULATING COMPOSITION 1 200 ml of ethylene glycol, 5.56 g of cross-linked bacterial cellulose, in wet cake (18% by weight solids) and 6.67 g of a 5% by weight solution of carboxymethylcellulose (CMC 7L) were combined in a masonry glass jar. deionized water. The ratio of crosslinked (active) bacterial cellulose: CMC, in this example, was 3: 1. A mixing blade assembly (Oster or Waring) was connected to the masonry vessel and the mixture was mixed at high speed for 10 to 20 minutes. The combined mixture was vacuum degassed.

EXAMPLE 3 INSULATING COMPOSITION 2 200 ml of ethylene glycol, 5.56 g of bacterial cellulose crosslinked in wet cake (18% solids and 0.67 g of a solid powder of carboxymethylcellulose (CMC 7L) was combined in a masonry glass container.The ratio of bacterial cellulose crosslinked in cake wet (active: CMC in this example was 2: 1.) A mixer blade assembly was connected to the masonry vessel, and the mixture was mixed at high speed for 10 to 20 minutes, the combined mixture was vacuum degassed.

EXAMPLE 4 INSULATING COMPOSITION 3 200 ml of ethylene glycol, 2 g of cross-linked bacterial cellulose, dry (50% active ingredient, 50% corn starch filler) and 0.5 g carboxymethylcellulose (CMC 7L) were combined in a masonry glass jar. The ratio of active cross-linked bacterial cellulose: CMC in this example was 2: 1. A mixing blade assembly was connected to the masonry vessel and the mixture was mixed at high speed for 10 to 20 minutes. The combined mixture was vacuum degassed.

METHOD OF PROOF OF HIGH TEMPERATURE STABILITY 180 ml of the cross-linked bacterial cellulose / ethylene glycol fluid of the insulating composition was placed in a clear, heat resistant container. Corroded pieces of mild steel were added to the fluid. An approximate metal surface ratio of 6 cm 3 / cm 2 was used. The corroded metal ingots were used to simulate the iron present in the submarine insulation pipe. The remaining volume of the vessel was purged with a stream of nitrogen and a lid was secured on the vessel. The container was placed in an oven at 80 ° C and was periodically observed for a period of 6 months. This sample maintained the thixotropic properties without detectable separation of the ethylene glycol during the whole period of one year. The separation of the base fluid could lead to the formation of convection currents and the concomitant loss of insulation properties.

EXAMPLE 5 COMPOSITION OF HYDROCOLOIDAL FLUID 7.5 g of crosslinked bacterial cellulose wet cake (18 wt.% Solids) was mixed with 500 ml of polyethylene glycol (PEG 200, Dow Chemical Co., Midland, Michigan, USA), using a Waring blender for 5 minutes, at speed "high" to give a viscous, homogeneous dispersion. 26 g of welan gum, sold by Kelco®, a unit of Monsanto, San Diego, California, E.U.A.), was added slowly, mixing at 640 r.p.m., using a propeller-type mixer. The resulting suspension of welan gum in the combination of crosslinked bacterial cellulose / polyethylene glycol was stable and did not sediment. Other variations and modifications, which will be obvious to those skilled in the art, are within the scope and teachings of this invention. This invention is not limited except as noted in the claims that follow.

Claims (13)

NOVELTY of the INVENTION CLAIMS

1. - A rheologically modified polyol composition, characterized in that it comprises: (i) cross-linked bacterial cellulose; and (ii) ethylene glycol; wherein said cross-linked bacterial cellulose is present in an amount effective to impart viscosity to the ethylene glycol, to substantially reduce the flow of the composition.

2. A rheologically modified polyol composition, characterized in that it comprises: (i) cross-linked bacterial cellulose; (ii) ethylene glycol; and (ii) cationic hydroxyethylcellulose or carboxymethylcellulose; wherein said cross-linked bacterial cellulose is present in an amount effective to impart viscosity to the ethylene glycol to substantially reduce the flow of the composition.

3. A method for thawing a surface of a substrate, characterized in that said method comprises the step of: applying to the surface of the substrate a rheologically modified composition, comprising crosslinked bacterial cellulose and a polyol-based fluid, wherein the Crosslinked bacterial cellulose is present in an effective amount to impart viscosity to the base polyol fluid to substantially reduce the flow of the composition.

4. - A method for using a rheologically modified polyol composition as a drilling fluid, characterized in that it comprises: pumping through a drill bit a modified polyol composition comprising crosslinked bacterial cellulose and a base polyol fluid; wherein the crosslinked bacterial cellulose is present in an approximate concentration of 0.005% to 2.0% by weight of the composition.

5. A method for using a rheologically modified composition as an anti-detachment agent, characterized in that it comprises: applying to a surface of a substrate a rheologically modified polyol composition comprising crosslinked bacterial cellulose and a base polyol fluid; wherein the crosslinked bacterial cellulose is present in an amount effective to impart viscosity to the base polyol fluid to substantially prevent the composition from flowing out of the surface of the substrate.

6. A fluid composition of thermal insulation, modified rheologically, characterized in that it comprises: (i) a cross-linked bacterial cellulose; (ii) a base polyol fluid; (Ii) at least one coagent; and (iv) a corrosion inhibitor; wherein the crosslinked bacterial cellulose is present in an amount effective to impart viscosity to the base fluid to substantially reduce convective flow in the composition.

7. A composition according to claim 6, further characterized in that it comprises a metal scavenger.

8. A method for thermally isolating a fluid transport member, characterized in that it comprises the step of: encircling an outer surface of the fluid transport member with a rheologically modified polyol composition, comprising crosslinked bacterial cellulose and a polyol fluid of base; wherein the crosslinked bacterial cellulose is present in an amount effective to impart viscosity to the base polyol fluid to substantially reduce convective flow in the composition.

9. A method according to claim 8, further characterized in that the polyol composition additionally comprises at least one co-agent and one corrosion inhibitor.

10. A fluid supply composition, characterized in that it comprises: (i) a cross-linked bacterial cellulose; (ii) a base polyol fluid; and (iii) a particulate material; wherein said cross-linked bacterial cellulose is present in an amount effective to suspend the particulate material in the fluid composition.

11. A method for suspending particulate material in a fluid composition, characterized in that it comprises the step of: adding a particulate material to a rheologically modified polyol composition comprising crosslinked bacterial cellulose and a base polymer fluid; wherein said bacterial cellulose is present in an amount effective to suspend the particulate material in the fluid composition.

12. - A fluid supply composn according to claim 10, further characterized in that the particulate material is a water soluble hydrocolloid material.

13. The composn according to any of claims 1-6, 8, 10 or 12, further characterized in that the base polyol fluid is selected from the group consisting of glycols, polyglycols and polyhydric alcohols.