Thickening additive

The base readily penetrates the hair and promotes bleaching. The addition of stabilizers such as sodium pyrophosphate or sodium oxalate [16,17] retards the decomposition of hydrogen peroxide in the alkaline preparation and thus enhances the bleaching action. The same holds for complexing agents (seques-trants) such as ethylenediaminetetraacetic acid, which hinder decomposition due to traces of heavy metals. Thickening additives include carboxymethyl celluloses, xanthine derivatives, and synthetic polymers. Certain dyes can also be added. 

Engine test used by Mack Track Company in specifying T-6, T-7 heavy-duty diesel lubricants. T-6 (piston deposit, oil consumption, and oil thickening) T-7 (oil thickening). Additive which prevents the oxidation-increasing catalytic effect of certain metals on the oil in the lubrication system, copper, lead, and iron are the most common. 

The third difficulty concerns application. Emulsions are intrinsically difficult to apply by any method (except, perhaps, spraying), since they have the viscosity of a solvent (the continuous phase). They are too fluid for brushing or dipping, for example. It therefore becomes necessary to raise the viscosity, either with thickener additives, or by use of resinous materials soluble in the continuous phase. The latter convert the continuous phase to a polymer solution, thus increasing its viscosity and therefore that of the paint. In either case, the material added to increase the viscosity must be compatible in the paint, or poor gloss and film integration will result. 

Thick films (125-250 pm) can be applied to verticals in one coat without sagging, by the inclusion of the usual thickening additives. The resin solution is easily pigmented, but care must be taken to avoid... 

Sodium methyl palmitoyl taurate Sodium methyl stearoyl taurate Sorbitan caprylate Steareth-2 Styrene/acrylates copolymer Tallowamidopropyl dimethylamine Tridecyl trimellitate Trihydroxystearin Welan gum Zinc laurate Zinc myristate thickener, cosmetics Microcrystalline wax thickener additive Acrylamide... 

Thickeners/gelling agents Forsthoff, 1991). Fatty alcohol ethoxylate, fatty acid alkylolamine, ethoxylated glucose ester and common salt are used as thickening additives in liquid washing, shower and bath preparations. Structurally viscous products retain their gel-like character by the addition of polymer gelling agents such as, polyacrylic acids, xanthan or hydroxypropyhnethylcellulose. However, the latter compound has been associated with a loss of efficacy for certain preservatives. 

Pigment dispersions, thermoplastic elastomer additives, thickeners additive concentrates... 

The solution is to prepare a concentrate which has viscosity characteristics similar to those of liquid antacids. The viscosity of a flowable concentrate will generally be in the range 2500-3500 cps. Either mineral thickeners alone or minerals in combination with polysaccharide gums can be employed as the thickening agent. While modified bentonites are used on occasion, attapulgites are most often the mineral of choice as the sole thickener (Sawyer, 1987). Combination thickeners are based on seaweed derived xanthan gum (a common food thickening additive) and montmorillonite (R.T. Vanderbilt). 

The base lubricant is usually a petroleum oil while the thickener usually consists of a soap or soap mixture. In addition they may contain small amounts of free alkali, free fatty acid, glycerine, anti-oxidant, extreme-pressure agent, graphite or molybdenum disulphide. 

Chain-Growth Associative Thickeners. Preparation of hydrophobically modified, water-soluble polymer in aqueous media by a chain-growth mechanism presents a unique challenge in that the hydrophobically modified monomers are surface active and form micelles (50). Although the initiation and propagation occurs primarily in the aqueous phase, when the propagating radical enters the micelle the hydrophobically modified monomers then polymerize in blocks. In addition, the hydrophobically modified monomer possesses a different reactivity ratio (42) than the unmodified monomer, and the composition of the polymer chain therefore varies considerably with conversion (57). The most extensively studied monomer of this class has been acrylamide, but there have been others such as the modification of PVAlc. Pyridine (58) was one of the first chain-growth polymers to be hydrophobically modified. This modification is a post-polymerization alkylation reaction and produces a random distribution of hydrophobic units. 

HydrophobicaHy Modified, Ethoxylated Urethane. HEUR associative thickeners are in effect poly(oxyethylene) polymers that contain terminal hydrophobe units (66). They can be synthesized via esterification with monoacids, tosylation reactions, or direct reaction with monoisocyanates. There are problems associated with aH of the methods of synthesis. The general commercial procedure for their synthesis is by a step-growth addition of... 

Addition Point. The flocculant addition point in a continuous system can also have a significant effect on flocculant performance. The turbulence as the flocculant is mixed in and the floes travel toward the point where they enter the thickener or filter causes both the formation and breakup of floes. Usually there is an optimal addition point or points which have to be determined empirically. In cases where the same polymer is being added at two or more points, the relative amounts added at each point may also affect performance. Thus providing multiple addition points in the design of new installations is recommended (56). 

Locust bean gum and its derivatives are exceUent film formers and can be used either alone or in combination with starch as textile sizing agents and dye thickeners in textile printing, and as fiber bonding and beater additives in the papermaking industry. However, in most of these appHcations it has been replaced by guar. 

Pa.ste Shampoos. These shampoos represent thickened versions of opaque shampoos. They have a somewhat firm, cream-like consistency and are packaged in jars and/or tubes. Thickening of these systems is usually accompHshed through additions of stearate soaps and electrolytes. 

Inorganic salts are also used to promote shampoo thickening. These should be used sparingly since an excess may have a deleterious effect on a product s physical stabiHty. Sodium chloride commonly is used in these cases. The additions of sodium stearate and stearic amides can be found in paste shampoos for thickening. 

High Water-Base Fluids. These water-base fluids have very high fire resistance because as Httle as 5% of the fluid is combustible. Water alone, however, lacks several important quaUties as a hydrauHc fluid. The viscosity is so low that it has Httle value as a sealing fluid water has Httle or no abiHty to prevent wear or reduce friction under boundary-lubrication conditions and water cannot prevent mst. These shortcomings can be alleviated in part by use of suitable additives. Several types of high water-based fluids commercially available are soluble oils, ie, od-in-water emulsions microemulsions tme water solutions, called synthetics and thickened microemulsions. These last have viscosity and performance characteristics similar to other types of hydrauHc fluids. 

The fluid is formulated from a premium mineral od-base stock that is blended with the required additive to provide antiwear, mst and corrosion resistance, oxidation stabdity, and resistance to bacteria or fungus. The formulated base stock is then emulsified with ca 40% water by volume to the desired viscosity. Unlike od-in-water emulsions the viscosity of this type of fluid is dependent on both the water content, the viscosity of the od, and the type of emulsifier utilized. If the water content of the invert emulsion decreases as a result of evaporation, the viscosity decreases likewise, an increase in water content causes an increase in the apparent viscosity of the invert emulsion at water contents near 50% by volume the fluid may become a viscous gel. A hydrauHc system using a water-in-od emulsion should be kept above the freezing point of water if the water phase does not contain an antifreeze. Even if freezing does not occur at low temperatures, the emulsion may thicken, or break apart with subsequent dysfunction of the hydrauHc system. 

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