Creaming


As an emulsion ages, the particle size distribution changes and the number of droplets decreases. On a global scale, the rate of creaming, as with milk, reflects the separation into concentrated and dilute emulsion phases. The droplet size distribution can be tabulated from cryoelectron microscopy (see Section VIII-2) photographs [15] or indicated by dynamic light scattering or NMR measurements. Larger particles are better characterized with a Coulter counter, where the electrical resistance is monitored as an emulsion flows through a small orifice. A size distribution is readily accumulated by monitoring the resistance as a series of particles pass through. Emulsion particle sizes often follow a lognormal distribution given by  [c.502]

As illustrated in Fig. XIV-8, at least three types of aging processes occur for emulsions. The inner phase droplets may undergo flocculation, that is, clustering together without losing their identity if, as part of or subsequent to flocculation, the flocks undergo a gravity separation, the entire process is called creaming. If coalescence occurs, then eventual breaking of the emulsion must follow, giving two liquid layers—see Refs. SO and SI for a general discussion  [c.510]

In section C2.6.4.3 it was shown how tlie addition of non-adsorbing polymer chains induces a depletion attraction between colloidal particles. If sufficient polymer is added, tliese attractions can be strong enough to induce a phase separation of tire colloidal particles. An early application of tliis was tire creaming of mbber latex [93].  [c.2688]

This publication provides several examples of the use of solid-phase extractions for separating analytes from their matrices. Some of the examples included are caffeine from coffee, polyaromatic hydrocarbons from water, parabens from cosmetics, chlorinated pesticides from water, and steroids from hydrocortisone creams. Extracted analytes maybe determined quantitatively by gas (GC) or liquid chromatography (LG).  [c.226]

Creaming Cream of tartar  [c.258]

Shape anisotropy Shape control Shape factors Shape-memory alloys Shape-selective catalysis Shape selectivity Sharpless catalyst Shaving cream Shaving creams  [c.882]

Spray shaving creams and furniture poHsh are examples of stable foams.  [c.344]

Emulsions. Aerosol emulsions (qv) may be oil in water (o/w), such as shaving creams, or water in oil (w/o), such as air fresheners and pohshes. These aerosols consist of active ingredients, an aqueous or nonaqueous vehicle, a surfactant, and a propellant, and can be emitted as a foam or as a spray.  [c.345]

Primary human skin irritation of tetradecanol, hexadecanol, and octadecanol is nil they have been used for many years ia cosmetic creams and ointments (24). Based on human testing and iudustrial experience, the linear, even carbon number alcohols of 6—18 carbon atoms are not human skin sensitizers, nor are the 7-, 9- and 11-carbon alcohols and 2-ethylhexanol. Neither has iudustrial handling of other branched alcohols led to skin problems. Inhalation hazard, further mitigated by the low vapor pressure of these alcohols, is slight. Sustained breathing of alcohol vapor or mist should be avoided, however, as aspiration hazards have been reported (25).  [c.446]

Cosmetics and Pharmaceuticals. The main use of hexadecanol (cetyl alcohol) is in cosmetics (qv) and pharmaceuticals (qv), where it and octadecanol (stearyl alcohol) are used extensively as emoUient additives and as bases for creams, Hpsticks, ointments, and suppositories. Octadecenol (oleyl alcohol) is also widely used (47), as are the nonlinear alcohols. The compatibiHty of heavy cut alcohols and other cosmetic materials or active dmg agents, their mildness, skin feel, and low toxicity have made them the preferred materials for these appHcations. Higher alcohols and their derivatives are used in conditioning shampoos, in other personal care products, and in ingested materials such as vitamins (qv) and sustained release tablets (see Controlled RELEASE technology).  [c.449]

When fat is present as the disperse phase of an emulsion, it contributes characteristic rheological and visual properties to foods thought of as creamy, eg, cream, mayonnaise, and pourable salad dressings. In standardized ice creams, fat is a significant factor in ice cream overmn, ie, the abiUty of the chilled mix to entrap air during freezing agitation, thus producing a lighter texture. When a separating salad dressing is compared to a creamy dressing, the dispersed oil droplets of the creamy dressing provide the rheological properties of increased viscosity, thixotropy, and viscoelasticity as well as visual whiteness and opacity.  [c.117]

Provided there is no mpture of the films, drainage proceeds until there develops a vertical, hydrostatic pressure gradient to offset gravity. The gradient is supported by the disjoining pressure due to the film thickness being too smaH to minimize the effective interface potential. Thus individual soap films in the foam decrease in thickness with increasing height. This results in a nonuniform gas Hquid volume fraction with the foam being more wet near the bottom of the container as in Eigure 1. The formation of a macroscopic layer of Hquid underneath a previously homogeneous foam is caHed gravitational syneresis, or creaming, and depends not only on the foam composition, but on the size and shape of the container as weH (21).  [c.429]

Drugs and Cosmetics. In dmgs and medicines, glycerol is an ingredient of many tinctures and elixirs, and glycerol of starch is used in jeUies and ointments. It is employed in cough medicines and anesthetics (qv), such as glycerol—phenol solutions, for ear treatments, and in bacteriological culture media. Its derivatives are used in tranquilizers (eg, glyceryl guaiacolate [93-14-1/), and nitroglycerin [55-65-0] is a vasodilator in coronary spasm. In cosmetics (qv), glycerol is used in many creams and lotions to keep the skin soft and replace skin moisture. It is widely used in toothpaste to maintain the desired smoothness, viscosity, and lending a shine to the paste (see Dentifrices).  [c.349]

Propylene glycol is an important solvent for aromatics in the flavor concentrate industry, enabling manufacturers to produce low cost flavor concentrates of high quaUty. It is also an excellent wetting agent for natural gums, greatly simplifying the compounding of citms and other emulsified flavors. PG also finds use as a solvent in elixirs and pharmaceutical preparations containing some water-soluble ingredients, and as a solvent and coupling agent in the formulation of sunscreen lotion, shampoos, shaving creams, and other similar products. Certain esters of propylene glycol such as propjdene glycol monostearate [1323-39-3] are also popular as an emulsifier in cosmetic and pharmaceutical creams.  [c.368]

Propylene glycol is also an effective humectant, preservative, and stabilizer and is found in such diverse apphcations as semimoist pet food, bakery goods, food flavorings, salad dressings, and shave creams. Humectancy, or the capabiUty of retaining moisture in a product, is a result of the vapor—Hquid equihbria of the glycol—water system and can be estimated from tables provided by suppHers (27).  [c.368]

Tripropylene Glycol. Tripropylene glycol is an excellent solvent in many apphcations where other glycols fail to give satisfactory results. Its abihty to solubilize printing ink resins is especially marked, so much so that it finds its way into creams designed to remove ink stains from the hands. A combination of water solubiUty and good solvent power for many organic compounds plus low volatiHty and a high boiling point also have led to its use by formulators of textile soaps and lubricants, cutting oil concentrates, and many similar products. Tripropylene glycol is also used as a reactant to produce acrylate resins which are usefiil in radiation-cured coatings, adhesives, and inks. Polyethers used in the manufacture of urethane rigid foam insulation are  [c.368]

High Solids Emulsions. Latices are made at the highest possible soHds content consistent with acceptable viscosity. Latices soHds can be increased by centrifuging, creaming, electrodecantation, or evaporation. The latter two techniques, however, are not of commercial importance. Natural mbber latex, 25—40 wt % soHds to start, is concentrated to about 60 wt % soHds by centrifuging with milk/cream separator equipment. Creaming is commonly used with synthetic polymer latices. Creaming is accelerated by adding solutions such as ammonium alginate and surfactant to the latex. Depending on the initial soHds content and type of latex, soHds contents of 58—65 wt % are possible.  [c.27]

Applications. Several food uses have been proposed for curdlan including jeUies, jams, noodles, and tofu (322). Its gelling properties make it useflil for the preparation of instant puddings and multiple layer puddings. It has been suggested that it may be useflil as a stabilizing agent in frozen desserts such as ice creams (322). Curdlan can be added to bind water, add stabiUty, and improve the body and gloss of food products.  [c.301]

Microcapsules are used in several film coatings other than carbonless paper. Encapsulated Hquid crystal formulations coated on polyester film are used to produce a variety of display products including thermometers. Polyester film coated with capsules loaded with leuco dyes analogous to those used in carbonless copy paper is used as a means of measuring line and force pressures (79). Encapsulated deodorants that release their core contents as a function of moisture developed because of sweating represent another commercial appHcation. Microcapsules are incorporated in several cosmetic creams, powders, and cleansing products (80).  [c.325]

Horizontal vats are employed for manual and mechanized operations. The starter may be blended with the incoming product or added at the vat. The setting temperature of the treated whey is typically 30°C and is held for 4.5—5 hours. The curd is cut when the titratable acidity is 0.52% for lactic acid milk with 9.0% nonfat milk soHds, or pH 4.6—4.7. The acidity controls the calcium level of the casein that determines many of the characteristics of the curd low acidity causes a mbbery curd, and high acidity causes a tender curd that shatters easily. The curd is cut by moving a knife first horizontally, then vertically, and finally crosswise through the vat. The cut curd is cooked about 30 minutes after cutting is finished. The temperature is gradually increased in increments of 0.5—1.0°C every 3—5 minutes to avoid the formation of a hardened protein layer that would inhibit moisture removal. After cooking, the whey is drained off and the curd is washed successively with cooler water, pasteurized or treated with chlorine, and rinsed at 4.4°C for firmness. Curd pumps move the curd to the blender where salt, cream, and stabilizer may be added. Creamed cottage cheese that has a fat content of at least 4% is produced by mixing in 12—14% fat cream.  [c.368]

Tetrahydronaphthalene [119-64-2] (Tetralin) is a water-white Hquid that is insoluble in water, slightly soluble in methyl alcohol, and completely soluble in other monohydric alcohols, ethyl ether, and most other organic solvents. It is a powerhil solvent for oils, resins, waxes, mbber, asphalt, and aromatic hydrocarbons, eg, naphthalene and anthracene. Its high flash point and low vapor pressure make it usehil in the manufacture of paints, lacquers, and varnishes for cleaning printing ink from rollers and type in the manufacture of shoe creams and floor waxes as a solvent in the textile industry and for the removal of naphthalene deposits in gas-distribution systems (25). The commercial product typically has a tetrahydronaphthalene content of >97 wt%, with some decahydronaphthalene and naphthalene as the principal impurities.  [c.483]

Creams are semisoHd emulsions either water-in-oil (w/o) or od-in-water (o/w). Generally, the ingredients of the two phases are heated separately to ca 70—80°C. The phases are then mixed and stirred vigorously to achieve emulsification. Such stirring is continued until the product has been cooled sufficiendy. Eor further reduction of the internal-phase droplets, the product may be passed through a homogenizer before final cooling. A soHd ingredient can be added to the appropriate phase before emulsification or maybe dispersed at some point after the emulsification step.  [c.233]

If the dmg is not soluble in the propellant, it is dissolved or dispersed in a Hquid vehicle. The propellant then constitutes the third phase of the system, and the container must be shaken before valve actuation. Emulsified aerosol products like lotions and creams are examples of such systems.  [c.235]

Use of a shoe poHsh imparts high gloss, maintains the supple hand of the leather (qv), and increases the weather resistance of the leather (3,57—59). Three general types of poHshes are produced solvent pastes, self-polishing Hquids, and emulsion creams. Solvent pastes represent ca 60% of the market (58).  [c.211]

Cosmetics and Personal Care Products. Alkanolamines ate important taw materials in the manufacture of creams (95—97), lotions, shampoos, soaps, and cosmetics. Soaps (98) formed from triethanolamine and fatty acids ate mild, with low alkalinity and excellent detergency. Triethanolamine lauryl sulfate is a common base for shampoos (99—101) and offers significant mildness over sodiumlauryl sulfate. Diethanolamine lauryl sulfate and fatty acid soaps of mono- and trietban olamine can also be used in shampoos and bubble bath formulations. Chemistry similar to that used in soluble oils and other emulsifiers is appUcable to cleansing creams and lotions (102,103). Alkanolamides or salts ate added to the shampoo base to give a smooth, dense foam (104).  [c.10]

When gases that are somewhat soluble in a Hquid concentrate are used, both concentrate and dissolved gas are expeUed. The dissolved gas then tends to escape into the atmosphere, dispersing the Hquid into fine particles. The pressure within the container decreases as the product is dispersed because the volume occupied by the gas increases. Some of the gas then comes out of solution, partially restoring the original pressure. This type of soluble compressed gas system has been used for whipped creams and toppings and is ideal for use with antistick cooking oil sprays. It is also used for household and cosmetic products either where hydrocarbon propeUants cannot be used or where hydrocarbons are undesirable.  [c.348]

There is more activity in dairy products than anywhere else in the food industry. Ice milk and fro2en yogurt, early leaders in the field, rose rapidly in sales then plummeted. Fat-free ice cream has been marketed, but final results are not yet available. Sales of these products have not cannibalized traditional ice cream (35). Standards for traditional ice cream call for a minimum of 10% butterfat. One fat-free ice cream product is prepared from nonfat milk (skim) and cellulose gum. Fat-free ice creams have encountered strong resistance in some segments of the retail trade. Retailers in Maine and New York, states with important dairy producing industries, refuse to sell such products (36).  [c.118]

Several techniques are available for the generation of special-purpose foam with the desired properties. The simplest method is to disperse compressed gas directly into an aqueous surfactant solution by means of a glass frit. A variation of this method that allows for control of Hquid content is to simultaneously pump gas and surfactant solution through a bead pack or steel wool, for example, at fixed rates. Less reproducible mechanical means of foam generation include bmte force shaking and blending. For highly reproducible foams composed of small bubbles, such as shaving creams, the aerosol technique is especially suitable (39) (see Aerosols). Hydrocarbons or chlorofluorocarbons are Hquefied at high pressure and then emulsified with the surfactant solution. When released to atmospheric pressure, the propeUant droplets evaporate into tiny gas bubbles which aggregate into a foam.  [c.431]

RepeUent compounds exhibit wide differences in their activity against various species of mosquitoes and flies, as weU as other biting arthropods, and it has been demonstrated that the overaU protection against various pests is greatly extended by the use of mixtures, eg, dimethyl phthalate indalone 2-ethyl-l,3-hexanediol, 3 1 1 parts by wt and dimethyl phthalate 2-ethyl-l,3-hexanediol dimethyl carbate, 4 3 3 parts by wt. These repeUents can be incorporated into various creams and lotions. AppUcations of the most effective materials give from one to six hours protection against mosquitoes and biting flies.  [c.304]

Inversion ofMon cjueous Polymers. Many polymers such as polyurethanes, polyesters, polypropylene, epoxy resins (qv), and siHcones that cannot be made via emulsion polymerization are converted into latices. Such polymers are dissolved in solvent and inverted via emulsification, foUowed by solvent stripping (80). SoHd polymers are milled with long-chain fatty acids and diluted in weak alkaH solutions until dispersion occurs (81). Such latices usually have lower polymer concentrations after the solvent has been removed. For commercial uses the latex soHds are increased by techniques such as creaming.  [c.27]

It is possible to iacrease the viscosity of a latex after manufacture using thickeners. Thickening occurs through increases in medium viscosity or polymer particle aggregation. If considerable aggregation occurs without a corresponding increase in medium viscosity, undesirable separation or creaming occurs. MethylceUulose, caseinates, and polyacrylate salts are typical thickeners. Ease of adding the thickener, abiUty to maintain viscosity, and undesirable side effects must be considered when selecting a thickener. Some thickeners slowly hydroly2e in the latex and lose their effectiveness over time. The full range of the effects of a dding thickener develops over time, some of them much faster than others. To avoid exceeding the desired viscosity, it is advisable to add thickener in small increments, waiting after each for the viscosity to reach equiUbrium before adding the next one.  [c.28]

Cosmetics and Soaps, One to five percent lecithin moisturizes, emulsifies, stabilizes, conditions, and softens when used ia products such as skin creams and lotions, shampoos and hair treatment, and Hquid and bat soaps. Siace the iatroduction of Capture ia 1986, liposomes produced from phosphohpids ate commercially available worldwide (36,37).  [c.104]

Cross-linked dextran known as dextranomer (Debrisan), which is similar to Sephadex, has been used in treating wounds. Fluids and small molecules are absorbed into the gel particles, and proteins and cellular material are excluded (205). Complexes of colloidal iron with dextran (206), known as iron—dextran [9004-66-4] are used in treating iron deficiency anemia. This use is limited mainly to animals, especially pigs, because iron—dextran has been listed as a suspected carcinogen. The abiHty of dextran to form stable complexes with metals is one of its more usehil properties. One of the largest markets for dextran is in the manufacture of photographic and x-ray films, where it is used to stabilize silver haHde emulsions. Another large market is in aluminum manufacturing, where dextran solutions are sometimes used in the recovery of aluminum from bauxite ores. Dextran has been used as a binder in tobacco products, and its use in shaving creams and other cosmetics (qv) has also been suggested. The U.S. FDA status of dextran as a food additive is not clear. Although GRAS approval of low molecular weight dextran as a direct food additive was dropped in 1977 (207), F. mesenteroides is approved for use in fermented foods (see Food additives). Because many foods of plant origin contain sucrose, it is virtually certain that any foods containing F. mesenteroides also contain dextran. In fact, some patents describing food appHcations of F mesenteroides B-523 and similar proprietary strains rely on the production of insoluble gelling dextran for key properties as food ingredients (209—211). Other food uses have been proposed for unusual dextrans.  [c.298]

Static mixers are used ia the chemical iadustries for plastics and synthetic fibers, eg, continuous polymeri2ation, homogeni2ation of melts, and blending of additives ia extmders food manufacture, eg, oils, juices, beverages, milk, sauces, emulsifications, and heat transfer cosmetics, eg, shampoos, hquid soaps, cleaning Hquids, and creams petrochemicals, eg, fuels and greases environmental control, eg, effluent aeration, flue gas/air mixing, and pH control and paints, etc.  [c.435]

Oil. Tung and oiticia are sources of quick-drying oils for the paint and varnish industry (see Drying oils). Coconut, babassu, and palm oils are used chiefly for the manufacture of margarine, soap, shaving cream, cosmetics (qv), and other domestic products. Walnut oil, a fine specialty oil having drying qualities, is used in the preparation of artists colors (see Pigments). Peanut oil is used as a lubricant and in shaving creams, shampoos, and cosmetics. It is also a good source of edible oil in the manufacture of shortening and margarine. Sweet almond oil is transparent, consisting chiefly of triolein. It has important uses as a laxative, in treating bronchitis and colds, and in fine soaps and cosmetics. Because most edible tree nuts are considered luxury food items, production of oil from these is usually not an economical practice except for specialty oils.  [c.278]

Aerosols. Pressurized containers to deHver aerosolized dmg products through appropriate systems of valves and actuators have been available since the 1950s (see Aerosols). Such dosage forms are used as external appHcations of lotions and creams, for oral inhalation, or for treatment of the vaginal cavity, eg, contraceptive foams. Aerosols contain two- or three-phase systems, wherein a volatile Hquid or admixture of Hquids is sealed in a  [c.234]

Specially designed impervious suits, eg. Level A suits, are utili2ed by workers handling some rocket fuels and other highly ha2ardous compounds (see Explosives and propellants). Barrier creams are much less effective than gloves for preventing skin contact.  [c.96]

They are similar to the paste furniture and floor poHshes, except that the former contain higher wax-to-solvent ratios and high levels of dye. The resulting film dries to a dull finish and must be buffed to a high shine. Liquid self-polishing products contain a soft polymer, which provides a more flexible coating, and coloring agents. The latter may be dyes or, in scuff-coat poHshes, pigments. Shoe creams can be made in any consistency. They are emulsions of waxes, solvents, and water. Formulas for shoe poHshes are Hsted in References 3 and 57. SiHcone waxes can also be used in shoe poHshes (60). The evaluation of shoe poHshes is reviewed in Reference 3. The evaluation of paste shoe poHshes is reviewed in Federal Specification P-P-557B (see also Leather Leather-like materials).  [c.211]

For dry-mbber compounding, the latex is coagulated, dried, and used in a soHd state after mechanically inducing plasticity. Latex compounding, on the other hand, is done in the Hquid state and the compounded latex used directly to form articles without being first converted to a separate soHd. For such use, the latex is usually concentrated to ca 60% solids by one of several methods, the most common of which is centrifuging a less common variant is creaming. For production of special, thin-wall dipped medical latex products, variants of the centrifuging process, such as double centrifuging or substaging, produce latex concentrate of higher purity. As with dry mbber, most uses of latex require modification by addition of vulcanizing agents and other ingredients stabilizers are also necessary. Exceptions are adhesives in which latex is used without modification by compounding.  [c.252]


See pages that mention the term Creaming : [c.53]    [c.130]    [c.234]    [c.1542]    [c.1044]    [c.433]    [c.451]    [c.494]    [c.225]    [c.255]    [c.255]   
Physical chemistry of surfaces (0) -- [ c.302 , c.510 ]