Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
1999-08-25
2001-06-19
Kopec, Mark (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S351000, C510S352000, C510S438000, C510S445000
Reexamination Certificate
active
06248709
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a process for producing a detergent composition. More particularly, the invention is directed to a non-tower process during which detergent granules are produced by adding co-surfactants. The process produces a free flowing, detergent composition whose density can be adjusted for wide range of consumer needs, and which can be commercially sold.
BACKGROUND OF THE INVENTION
Recently, there has been considerable interest within the detergent industry to produce modern detergent compositions for flexibility in the ultimate density of the final composition.
Generally, there are three primary types of processes by which detergent granules or powders can be prepared. The first type of process involves spray-drying an aqueous detergent slurry in a spray-drying tower to produce highly porous detergent granules (e.g., tower process for low density detergent compositions). The second type of process involves spray-drying an aqueous detergent slurry in a spray-drying tower as the first step, then, the resultant granules are agglomerated with a binder such as a nonionic or anionic surfactant, finally, various detergent components are dry mixed to produce detergent granules (e.g., tower process plus non-tower [agglomeration] process for high density detergent compositions). In the third type of process, the various detergent components are dry mixed after which they are agglomerated with a binder such as a nonionic or anionic surfactant, to produce high density detergent compositions (e.g., non-tower [agglomeration] process for high density detergent compositions). In the above three processes, the important factors which govern the density of the resulting detergent granules are the shape, porosity and particle size distribution of said granules, the density of the various starting materials, the shape of the various starting materials, and their respective chemical composition.
It is often desirable, for performance reasons, to use a mixture of surfactants. Such surfactants are typically prepared in the form of aqueous pastes (typically 25-70% active). When preparing agglomerated granules from mixtures of such surfactant pastes, there are two approaches generally used. One typical approach is; surfactants in the form of paste are mixed so as to form a co-surfactant paste, followed by agglomerating the paste in a mixer, or in a series of mixers with dry ingredients such as builders (e.g. sodium tripolyphosphate), inorganic fillers (e.g. sodium sulfate), bleaches, etc. This approach is not always desirable in terms of finished product quality. For example, mixing of even a relatively small amount of a non-crystalline surfactant paste, (i.e. the paste of a type of surfactant which is typically sticky and difficult to be applied in an agglomeration process), with a paste of a crystalline surfactant, (i.e. a type which is typically easy to apply in an agglomeration process), results in a co-surfactant paste that has the nature of paste of a non-crystalline surfactant. In other words, this type of approach typically causes stickiness of a co-surfactant paste, when co-surfactants include a non-crystalline surfactant, since such non-crystalline surfactant is generally sticky. Consequently, the granules made by this approach generally include a large amount of undesirable oversized agglomerates. Some reduction in the amount of oversize agglomerates can be achieved by using relatively large amounts of flow aids such as zeolites and silicates in the agglomeration step. This, however results in added expense. Another typical approach is, each type of surfactant is formulated into separate agglomerates and then both agglomerates are blended. This approach typically is not desirable since the cost for the parallel agglomeration is rather expensive.
Accordingly, there remains a need in the art to have a process for producing a detergent composition which reduces the level of resulting undesirable oversized agglomerates, when starting detergent materials include a co-surfactant which is non-crystalline. Also, there remains a need for such a process which is more efficient, flexible and economical to facilitate large-scale production of detergents for flexibility in the ultimate density of the final composition.
BACKGROUND ART
The following references are directed to densifying spray-dried granules: Appel et al, U.S. Pat. No. 5,133,924 (Lever); Bortolotti et al, U.S. Pat. No. 5,160,657 (Lever); Johnson et al, British patent No. 1,517,713 (Unilever); and Curtis, European Patent Application 451,894.
The following references are directed to producing detergents by agglomeration: Beerse et al, U.S. Pat. No. 5,108,646 (Procter & Gamble); Capeci et al, U.S. Pat. No. 5,366,652 (Procter & Gamble); Hollingsworth et al, European Patent Application 351,937 (Unilever); and Swatling et al, U.S. Pat. No. 5,205,958.
The Japanese Patent Application, Laid-open No H5-171199 (Lion), describes a high bulk density granular detergent composition comprising a fatty acid lower alkyl ester sulfonate (“Co-surfactant I”) and an anionic surfactant other than Co-surfactant I, silicate, and carbonate. This composition is disclosed as preventing the hydrolysis of Co-surfactant I after long term shortage.
SUMMARY OF THE INVENTION
The present invention meets the aforementioned needs in the art by providing a non-tower process, especially agglomeration process, which produces a granular detergent composition having ultimate density of the final granular composition. The present process is stable in terms of flow ability and cost effective, since the process reduces the level of undesirable oversized granules and/or the level of process flow aids, such as zeolites and/or silicates, that prevent over agglomeration. Consequently, the process of the present invention is more efficient, economical and flexible with regard to obtaining detergent compositions having less oversized granules (i.e., agglomerates).
As used herein, the term “agglomerates” refers to particles formed by agglomerating raw materials with binder such as surfactants and or inorganic solutions/organic solvents and polymer solutions. As used herein, the term “crystalline (anionic) surfactant paste” refers to the (anionic) surfactant paste having crystalline structure, generally having about 50-100%, preferably about 65-100%, more preferably about 80-100% of crystallinity, measured by X-Ray Diffraction (XRD). As used herein, the term “non-crystalline (anionic) surfactant paste” refers to the (anionic) surfactant paste which is not crystalline (anionic) surfactant paste defined as the above. All percentages used herein are expressed as “percent-by-weight” unless indicated otherwise.
The present invention provides a process for preparing a granular detergent composition, the process comprising: (a) thoroughly mixing a crystalline anionic surfactant paste with a sufficient amount of fine powders of starting detergent materials form a free flowing agglomerate; (b) thoroughly mixing a product of the step (a) with a non-crystalline anionic surfactant paste to form a free flowing agglomerate; is provided. An agglomerate from the process of the present invention has a reduced level of resulting undesirable oversized granules.
Also provided are the granular detergent compositions produced by any one of the process embodiments described herein.
Accordingly, it is an object of the invention to provide a process for continuously producing a free flowing agglomerate, which reduces the level of resulting undesirable oversized granules. It is also an object of the invention to provide a process which is more efficient, flexible and economical to facilitate large-scale production of detergents of low as well as high dosage levels. These and other objects, features and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment and the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMB
Kandasamy Manivannan
Naemura Kenji
Bolam Brian M.
Kopec Mark
Miller Steven W.
Mruk Brian P.
The Procter & Gamble & Company
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