Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2001-08-28
2004-05-04
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S130000, C510S208000, C510S213000, C510S226000, C510S421000, C510S432000, C510S438000
Reexamination Certificate
active
06730651
ABSTRACT:
FIELD OF THE INVENTION
A stock composition, which can be pre-mixed or stored, for further use in detergent or personal care compositions, the stock comprising a high concentration of capsules which are desired for incorporation into the final consumer product.
BACKGROUND OF THE INVENTION
In many articles of commerce, particularly consumer products, it is desirable to separate certain ingredients, yet have them disposed in a common container. Separation is particularly beneficial where one or more ingredients have negative interactions with each other. For example, in laundry detergents, enzymes are useful in removing stains but it is also best to separate them from other constituents, such as sources of alkalinity and surfactants, especially anionic surfactants like linear alkylbenzene sulfonates or alkyl sulfates. Bleaches, vitamins, perfumes, vegetable oils, plant extracts and ceramides are further examples of ingredients that sometimes need to be separated from the rest of the detergent or personal care composition.
A known technique for separating ingredients in a common container includes encapsulation. Encapsulation technology is well known for different applications. Generally, encapsulation includes a medium that surrounds at least one component and thereby provides a barrier between the “encapsulated” component and other components. The barrier is typically temporary and is designed to break down and release the encapsulated material at a desired time, such as at a particular temperature, upon reaction or dissolution with chemicals, or due to mechanical stress. Methods of encapsulation include coacervation, liposome formation, granulation, coating, emulsification, atomization and spray-cooling.
See, for instance, the disclosures of enzyme encapsulates and encapsulation processes: Falholt et al. (U.S. Pat. No. 4,906,396, UK 2,186 884, and EP 0 273 775), Tsaur et al. (U.S. Pat. Nos. 5,434,069 and 5,441,660), Ratuiste et al. (U.S. Pat. No. 5,589,370). JP 41003667 discloses a dialysis of a protein solution against polyol-base polymer. WO 01/05949 discloses a method for densifying enzyme capsules. See also Mitchnik et al. (U.S. Pat. No. 5,733,531) and Leong (U.S. Pat. No. 5,296,166).
It is also desirable in the manufacturing process to prepare a stock of capsules, so that the capsules may be shipped or stored. In order to prepare such stock, it is necessary to prevent capsule agglomeration after formation and on storage: known capsules frequently agglomerate due to tacky hydrophobic encapsulating materials at the capsule surface. The agglomeration problem is exacerbated when capsule concentration is increased in an attempt to prepare a concentrated stock of capsules.
SUMMARY OF THE INVENTION
The present invention includes concentrated stock composition of capsules for incorporation into detergent or personal care composition, the stock composition comprising a high concentration of capsules comprising a hydrophobic material for forming the capsules, and a supernatant comprising water and a high HLB surfactant and/or a superwetting agent.
The following detailed description and the examples illustrate some of the effects of the inventive compositions. The invention and the claims, however, are not limited to the following description and examples.
DETAILED DESCRIPTION OF THE INVENTION
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about.” All amounts are by weight, unless otherwise specified.
For the avoidance of doubt the word “comprising” is intended to mean including but not necessarily “consisting of” or “composed of”. In other words the listed steps or options need not be exhaustive.
The term “continuous” does not necessarily mean “isotropic”. The term “continuous” is used herein to denote the phase which is predominant in volume during emulsification or dispersion of discontinuous phase in the continuous phase.
The term “hydrocarbon oil” as used herein means a hydrocarbon oil having a maximum viscosity of about 10 kg/(m)(sec), preferably no greater than about 5 kg/(m)(sec).
The term “wax” as used herein means a hydrophobic material which is a solid at 20° C. By “solid” is meant the ingredient is not mobile at 20° C.
Capsules
The inventive stock compositions comprise a high amount of capsules. The stock compositions may be conveniently stored or shipped. The problem of agglomeration is avoided due to the presence in a supernatant part of the composition of a high HLB surfactant and/or super-wetting agent.
The capsules are formed of a hydrophobic material such as, for example, paraffin, oil, wax or petroleum jelly (“petrolatum”), a polymer, and mixtures thereof. However, it is within the scope of the present disclosure that other suitable materials can be used as the shell material. The desired ingredient for the encapsulation may form a continuous phase with the hydrophobic material (it can then be co-melted with the hydrophobic material) or it may form a discontinuous phase. In the latter case, the hydrophobic material forms a continuous phase, which surrounds a discontinuous phase. A hybrid of the two cases is also possible, i.e. both the continuous and discontinuous phases contain benefit ingredient(s) and/or colorant(s).
In one preferred embodiment of the invention, a mixture of a thermoplastic block co-polymer and a hydrocarbon oil is employed as the hydrophobic material, particularly when it is desired to make transparent capsules. The block co-polymers particularly suitable in the present invention are block co-polymers containing at least one rigid block and at least one flexible block. The mixture of the hydrocarbon oil and the block co-polymer according to the present invention is isotropic at 20° C. It should be understood that since the co-polymer is not pourable at 20° C. (indeed, it is solid), it may be difficult to combine the co-polymer with the oil at such temperature to ascertain whether the mixture is isotropic. According to the present invention, a mixture may be formed at any suitable temperature at which the liquefied co-polymer forms an isotropic liquid mixture with the oil. The copolymer/oil mixtures suitable for use in the present invention, however, remain isotropic after cooling. Suitable isotropic mixtures have transmittance of at least 50%, preferably at least 70% as measured by UV-visible spectrophotometer (measured in the visible light range).
Block Co-polymer
In one embodiment of the invention, the co-polymer employed for forming the capsules is selected from the group consisting of a triblock co-polymer, radial co-polymer, and multiblock co-polymer, the co-polymer comprising at least one triblock with a structure: rigid block—flexible block—rigid block. Preferably the rigid block is styrene-type polymer, and the flexible block is rubber-type polymer. By virtue of employing the rigid-flexible-rigid block co-polymer, the viscosity of the oil is increased, and the hardened capsule is formed, yet the resulting capsule is sufficiently soft and friable to release the benefit ingredient in normal use. The co-polymer blends uniformly with oil at a temperature which is much lower than the melting point of wax, thus allowing for encapsulation of temperature-sensitive ingredients, e.g. bleach, perfume, enzyme, vegetable oil, etc.
The preferred co-polymers are transparent and uncolored, in order to attain a transparent and uncolored continuous phase.
Examples of suitable co-polymers include but are not limited to those that are described in Morrison et al. (U.S. Pat. No. 5,879,694) hereby incorporated by reference herein.
Each of the triblock, radial block and/or multiblock copolymers in the invention contains at least two thermodynamically incompatible segments. By the expression thermodynamically incompatible with respect to the polymers, it is meant that the polymer contains at least two incompatible segments, for example at
Bae-Lee MyongSuk
Bowens Tracy
Ehrnsperger Eric Charles
Hsu Feng-Lung Gordon
Neuser Kristina Marie
Mitelman Rimma
Ogden Necholus
Unilever Home & Personal Care USA Division of Conopco. Inc.
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