Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-04-05
2002-04-02
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C523S105000, C524S504000, C524S531000, C424S070100, C424S078030
Reexamination Certificate
active
06365656
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to liquid dispersion polymer compositions which comprise a dispersed polymer phase, a continuous carrier phase and a surfactant, their preparation and the use of these liquid dispersion polymer compositions to prepare microparticulate thickening systems which thicken aqueous or aqueous/organic compositions. More particularly it relates to liquid dispersion polymer compositions which comprise microparticles of a hydrophilic, water soluble or swellable polymer, preferably an acrylic-based polymer, which is dispersed in a di- or triglyceride oil carrier phase and an oil-in-water surfactant, their preparation and the use of these liquid dispersion polymer compositions to prepare microparticulate thickening systems to thicken aqueous or aqueous/organic compositions, particularly for use in personal care and pharmaceutical formulations.
Thickeners are used extensively in personal care formulations such as cosmetic and pharmaceutical formulations, to affect the aesthetics, product application and suspension and delivery of the active raw materials. Polymeric thickeners have been used for this purpose for many years. The types of polymeric thickeners that have been used range from natural gums such as guar, through modified natural materials such as hydroxyethyl cellulose, to synthetic thickeners such as the Carbomers® based on polyacrylic acids.
The Salcare® range of liquid dispersion polymers, available through Ciba Specialty Chemicals, High Point, N.C., is a range of microparticulate acrylic-based polymeric thickeners in a hydrophobic carrier medium. Salcare® SC91 is an anionic thickening agent based on a sodium acrylate polymer and mineral oil carrier with PPG-1 trideceth-6 as the activator surfactant. Salcare® SC92 is a cationic copolymer thickener and conditioner comprising polyquaternium 32 and mineral oil. Salcare® SC95 and Salcare® SC96 are cationic homopolymer thickeners and conditioners. Salcare® SC95 comprises polyquaternium 37 in mineral oil with PPG-1 trideceth-6. Salcare® SC96 comprises polyquaternium 37 in propylene glycol dicaprylate dicaprate with PPG-1 trideceth-6.
The tiny, spherical microparticles of the above hydrophilic acrylic polymers, whether anionic or cationic in charge, have a typical particle size in the range of 0.1-2 microns, with an average particle size in the range of 0.5-1.0 microns. The polymer microparticles are preferably manufactured by methods in which water soluble vinyl addition monomers are polymerized utilizing a water-in-oil polymerization route.
On stirring of any of the above liquid dispersion polymers into an aqueous system, the activator surfactant converts the hydrophobic carrier into an oil-in-water emulsion. By the term “activator surfactant” is meant a surfactant which activates the conversion of the hydrophobic carrier into an oil-in-water emulsion. At the same time the hydrophilic polymer expands on exposure to water but does not dissolve, resulting in a smooth and rapid viscosity increase. Typically the polymer particles swell to give a microparticulate thickening system comprising polymer particles having a typical particle size in the range of 2.5-5 microns in diameter. Since the water molecules move into the small polymer particles by osmosis, the osmotic effect experienced by the polymer particle is a balance between water and any electrolyte present in the system. Hence high electrolyte levels reduce the swelling of the polymer particles.
The microparticulate thickening systems have a pseudoplastic Theological profile which gives good stability and suspension characteristics at low shear rates (such as those experienced by the product on standing), and low apparent viscosities at high shear rates, which corresponds to excellent rub-in characteristics.
As previously mentioned, the continuous organic carrier phase for the above Salcare® liquid dispersion polymers is either mineral oil or a synthetic glycol ester, propylene glycol dicaprylate dicaprate. Mineral oil is known to provide good barrier properties to the skin. Now however it has been found that liquid dispersion polymer compositions which comprise microparticles of a hydrophilic, water soluble or swellable polymer as the dispersed polymer phase, a di- or triglyceride oil as the continuous organic carrier phase and an oil-in-water surfactant, offer a number of advantages to the personal care end user. Like the known Salcare® liquid dispersion polymers, the inventive liquid dispersion polymers provide microparticulate thickening systems which give effective thickening to aqueous or aqueous/organic personal care formulations at concentrations of 0.1% to 8%, preferably 1% to 6%, by weight. In addition however they combine the thickening effect of the liquid dispersion polymer with the advantages of a cosmetically acceptable di- or triglyceride carrier oil. Thus the resulting oil-in-water microparticulate thickening emulsions provide excellent moisturizing properties and excellent emolliency to skin care formulations, leading to smooth skin with good elasticity. Additionally, since the activator remains outside the swollen particle, other synthetic or natural oils, including silicones, can be readily emulsified without the need for calculation of the HLB, heating, neutralization or use of additional emulsifiers. This means that the thickener can be used to produce personal care emulsions by a very simple room temperature production process in a shorter manufacturing time, and multiple ingredients which may include two phases can be mixed in one vessel prior to addition of the thickener. Additionally, by selection of an appropriate cationic or anionic polymer, thickened compositions which are compatible with a variety of cationic or anionic co-ingredients can be obtained.
SUMMARY OF THE INVENTION
In one aspect the present invention provides a liquid dispersion polymer composition comprising a hydrophilic, water soluble or swellable polymer as a dispersed polymer phase, a di- or triglyceride oil as a continuous organic carrier phase and an oil-in-water surfactant, wherein the polymer is in the form of microparticles having an average particle size in the range of 0.1 to 2 microns.
Typically the liquid dispersion polymer composition comprises
a) from 35% to 65% by weight of the polymer,
b) from 20% to 50% by weight of a di- or triglyceride oil, and
c) from 5% to 25% by weight of a surfactant or a surfactant mixture, each based on the total weight of the composition.
Advantageously the hydrophilic polymer a) is water swellable, i.e. it is sufficiently crosslinked to swell but not dissolve in water. Preferably it is acrylic-based. Also it is preferably anionic or cationic.
The di- or triglyceride oil b) may be of natural or synthetic origin. Preferably it is of animal or plant origin. Most preferably the oil is a naturally occurring triglyceride vegetable oil.
Soybean oil is especially preferred.
The surfactant or surfactant mixture c) is advantageously a mixture of surfactants. Preferably the mixture comprises both surfactants useful in the manufacture of the microparticles of swellable polymer a), and at least one surfactant which serves as the activator for the subsequent oil-in-water microparticulate thickening emulsions. This activator surfactant for the oil-in-water thickening emulsions comprises from 0.5% to 8% by weight of the composition, preferably from 1% to 3% by weight of the composition. It has been found that when the liquid dispersion polymer composition comprises a di- or triglyceride oil as the continuous phase, substantially less of the activator surfactant is needed than with the less polar mineral oil. Preferably the activator surfactant is a nonionic oil-in-water emulsifier having a HLB generally above 10. Suitable emulsifiers of this type are well known to those skilled in the art. Ethoxylated alcohols are preferred, with PPG1-trideceth 6 being especially preferred.
Additionally the composition may contain minor amounts of other components which do not affect its essential characteristics. Typically
Gavin Dwayne Erick
Green Michael
Ridley Eleanor Bernice
Ciba Specialty Chemicals Corporation
Mansfield Kevin T.
Yoon Tae H.
LandOfFree
Liquid dispersion polymer compositions, their preparation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid dispersion polymer compositions, their preparation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid dispersion polymer compositions, their preparation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2835574