Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Spray cooling process – or product thereof
Reexamination Certificate
2001-04-12
2003-09-30
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Spray cooling process, or product thereof
C510S276000, C510S438000, C034S284000, C034S287000, C034S288000
Reexamination Certificate
active
06627597
ABSTRACT:
TECHNICAL FIELD
The present invention relates to nanoporous granular materials, and more particularly, to a process for producing a starting material in a granular form and in a nanoporous anhydrous state, a process for improving the water-solubility and controlled release characteristics of a detergent material, and a detergent composition.
BACKGROUND OF THE INVENTION
Starting materials in the granular form, such as those used for making detergent compositions, have various disadvantages related to the lack of particle size and particle pore size uniformity. One major disadvantage resulting from granular materials having non-uniform pore size, low porosity and non-uniform size distribution is that the solubility of the detergent composition in water is detrimentally affected. Currently, detergent formulators are faced with numerous problems which impede delivering the active ingredients to the fabric or dishware to be cleaned. By way of example, recent low dosage or “compact” detergent products experience dissolution problems, especially in cold temperature laundering solutions (i.e., less than about 30° C.). More specifically, poor dissolution results in the formation of “clumps” which appear as solid white masses remaining in the washing machine or on the laundered clothes after conventional washing cycles. These “clumps” are especially prevalent under cold temperature washing conditions and/or when the order of addition to the washing machine is such that the laundry detergent is added first, the clothes are added thereafter and the water is added in the end, commonly known as the “Reverse Order Of Addition” or “ROOA”. Similarly, this clumping phenomenon can contribute to the incomplete dispensing of detergent in washing machines equipped with dispenser drawers or in other dispensing devices, such as a granulettes. In such cases, the undesired result is undissolved detergent residue in the dispensing device.
Another disadvantage is that non-uniform granular materials for detergent applicants do not have a high amount of liquid loading capability, which is necessary, for example, for loading perfume onto a detergent granule. Also it has been recognized by the inventors of this invention that larger pore size and non-uniform pore size distribution in a granular detergent composition leads to lower active agglomerates, i.e., agglomerates that do not have the level of activity desirable for detergent applications.
Another disadvantage of this particle size non-uniformity in powdered starting materials is the presence of sometimes significant amounts of very fine particles which very frequently lead to safety and health problems due to the risk of dusting and pollution by these very fine particles. Consumers of detergent compositions do not want to be exposed to detergent agglomerates that have these undesirable dusting characteristics. Another problem in the detergent area is that the non-uniform size caused the granular starting materials to generally flow with difficulty, which makes it difficult to handle them and in particular, to dose them correctly during usage.
It is very desirable to produce starting materials, such as detergent materials, in the form of granules, that is to say, agglomerates of powder grains having a regular shape, an even surface, a nanoporous sized porosity, and of a generally graded size. The desirability of creating nanoporous sized granular starting materials for laundry and cleaning applications, such as in detergent compositions has been recognized by the inventors of this invention and it has been their focus to develop a process and product that results in granular materials that dissolve easily, are high active agglomerates and that have high liquid loading capability. It has been recognized that in the non-detergent applications, these nanoporous sized granules, which are less volatile than particles of powder, exhibit an appreciably reduced risk of atmospheric pollution and consequently of poisoning by inhalation via the respiratory tract, in the case of toxic starting materials. Further, when the starting material is provided in the form of granules having a regular shape, an even surface and a graded size, it can easily be handled, especially owing to ease of flow, and in particular it is easy to carry out the precise automatic weighing thereof for packaging purposes as well as dosing during subsequent uses. The present invention overcomes the problems, as set forth above.
BACKGROUND ART
Lyophilization is a known technique for obtaining anhydrous products which comprises the desiccation, by sublimation, of a product which has been solidified beforehand by freezing. This lyophilization is used for the manufacture of pharmaceutical, cosmetic, food or veterinary products in pulverulent form.
Published Japanese Patent Application JP 87 305 829 describes the preparation of a chitosan powder by dissolving chitosan in an acid, suspending, freezing and lyophilizing in order to obtain chitosan granules. Such a process does not make it possible to obtain granules with an even surface and with a homogeneous size, and in the nanoporous pore size range.
Published Japanese Patent Application JP 81 152 449 describes a process for the production of a fine powder which consists in dissolving a vehicle substance in an alcoholic solvent, in spraying the solution in an atmosphere at a temperature of less than −40 degrees C. in order to obtain frozen granulated fines and in drying the granules under vacuum while retaining them in the frozen state. Owing to the fact that the granules are formed by spraying by means of a propellant gas, the flow obtained is in the form of a more or less continuous thin stream and it is not possible to obtain frozen granules of homogeneous size, nor are they nanoporous.
U.S. Pat. No. 5,611,973 issued to Gurfein et al. on Mar. 18, 1997 discloses a process for producing a starting material, and in particular colouring materials, in the form of anhydrous granules having a regular shape, an even surface and a graded size. This process provides granules having sufficient cohesion for their subsequent uses and provides granules having a microporous structure which facilitates subsequent dissolution of the product. However, this patent does not provide a process for producing nanoporous size granular starting materials that have markedly improved solubility, activity, liquid loading capability and particularly, nanoporous granular materials for detergent applications.
SUMMARY OF THE INVENTION
The invention meets the needs above by providing a process for producing a starting material in a granular form and in a nanoporous anhydrous state, a process for improving the water-solubility and controlled release characteristics of a detergent material, and a detergent composition.
In one aspect of the present invention, a process for producing a starting material in a granular form and in a nanoporous anhydrous state is disclosed. The process includes the steps of obtaining a starting material in a form of a dispersion or solution in a sublimable solvent or mixtures of sublimable solvents, forming graded droplets by atomization, freezing the graded droplets in a freezing medium at a controlled freezing rate of at least 100° C. per second to form frozen droplets and drying the frozen droplets by vacuum sublimation to obtain freeze-dried granules of the starting material in a nanoporous anhydrous state. The starting material in dispersion or solution form has a viscosity suitable for atomization and formation of graded droplets.
In another aspect of the present invention, a process for improving water-solubility and controlled release characteristics of a detergent material is disclosed. The process includes the steps of obtaining a detergent starting material in a form of a dispersion or solution in a sublimable solvent or mixtures of sublimable solvents, forming graded detergent droplets by atomization, freezing the graded detergent droplets in a freezing medium at a controlled freezing rate of at least 100° C. per second to form froz
Achanta Srinivas
France Paul Amaat
Bolam Brian M.
Corstanje Brahm J.
Douyon Lorna M.
Miller Steven W.
The Procter & Gamble & Company
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