Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
1999-04-01
2001-04-03
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S351000, C510S361000, C510S441000, C510S442000, C510S495000, C510S498000, C510S509000, C510S510000, C510S512000
Reexamination Certificate
active
06211138
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a non-tower process for producing a particulate detergent composition. More particularly, the invention is directed to a continuous process during which detergent agglomerates are produced by feeding a surfactant and coating materials into a series of mixers. 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 for laundry detergents which are “compact” and therefore, have low dosage volumes. To facilitate production of these so-called low dosage detergents, many attempts have been made to produce high bulk density detergents, for example with a density of 600 g/l or higher. The low dosage detergents are currently in high demand as they conserve resources and can be sold in small packages which are more convenient for consumers. However, the extent to which modern detergent products need to be “compact” in nature remains unsettled. In fact, many consumers, especially in developing countries, continue to prefer a higher dosage levels in their respective laundering operations.
Generally, there are two 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). In the second 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., agglomeration process for high density detergent compositions). In the above two 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.
There have been many attempts in the art for providing processes which increase the density of detergent granules or powders. Particular attention has been given to densification of spray-dried granules by post tower treatment. For example, one attempt involves a batch process in which spray-dried or granulated detergent powders containing sodium tripolyphosphate and sodium sulfate are densified and spheronized in a Marumerizer®. This apparatus comprises a substantially horizontal, roughened, rotatable table positioned within and at the base of a substantially vertical, smooth walled cylinder. This process, however, is essentially a batch process and is therefore less suitable for the large scale production of detergent powders. More recently, other attempts have been made to provide continuous processes for increasing the density of “post-tower” or spray dried detergent granules. Typically, such processes require a first apparatus which pulverizes or grinds the granules and a second apparatus which increases the density of the pulverized granules by agglomeration. While these processes achieve the desired increase in density by treating or densifying “post tower” or spray dried granules, they are limited in their ability to go higher in surfactant active level without subsequent coating step. In addition, treating or densifying by “post tower” is not favourable in terms of economics (high capital cost) and complexity of operation. Moreover, all of the aforementioned processes are directed primarily for densifying or otherwise processing spray dried granules. Currently, the relative amounts and types of materials subjected to spray drying processes in the production of detergent granules has been limited. For example, it has been difficult to attain high levels of surfactant in the resulting detergent composition, a feature which facilitates production of detergents in a more efficient manner. Thus, it would be desirable to have a process by which detergent compositions can be produced without having the limitations imposed by conventional spray drying techniques.
To that end, the art is also replete with disclosures of processes which entail agglomerating detergent compositions. For example, attempts have been made to agglomerate detergent builders by mixing zeolite and/or layered silicates in a mixer to form free flowing agglomerates. While such attempts suggest that their process can be used to produce detergent agglomerates, they do not provide a mechanism by which starting detergent materials in the form of pastes, liquids and dry materials can be effectively agglomerated into crisp, free flowing detergent agglomerates.
Accordingly, there remains a need in the art to have an agglomeration (non-tower) process for continuously producing a detergent composition having high density delivered directly from starting detergent ingredients, and preferably the density can be achieved by adjusting the process condition. Also, there remains a need for such a process which is more efficient, flexible and economical to facilitate large-scale production of detergents (1) for flexibility in the ultimate density of the final composition, and (2) for flexibility in terms of incorporating several different kinds of detergent ingredients, especially detergent ingredients in the form of liquid, into the process.
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: Beujean et al, Lid-open No.WO93/23,523 (Henkel), Lutz et al, U.S. Pat. No. 4,992,079 (FMC Corporation); Porasik et al, U.S. Pat. No. 4,427,417 (Korex); 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); Swatling et al, U.S. Pat. No. 5,205,958; Dhalewadikar et al, Laid Open No.WO96/04359 (Unilever).
For example, the Laid-open No.WO93/23,523 (Henkel) describes the process comprising pre-agglomeration by a low speed mixer and further agglomeration step by high speed mixer for obtaining high density detergent composition with less than 25 wt % of the granules having a diameter over 2 mm. The U.S. Pat. No. 4,427,417 (Korex) describes continuous process for agglomeration which reduces caking and oversized agglomerates.
None of the existing art provides all of the advantages and benefits of the present invention.
SUMMARY OF THE INVENTION
The present invention meets the aforementioned needs in the art by providing a process which produces a high density granular detergent composition. The present invention also meets the aforementioned needs in the art by providing a process which produces a granular detergent composition for flexibility in the ultimate density of the final composition from agglomeration (e.g., non-tower) process. The process does not use the conventional spray drying towers currently which is limited in producing high surfactant loading compositions. In addition, the process of the present invention is more efficient, economical and flexible with regard to the variety of detergent compositions which can be produced in the process. Moreover, the process is more amenable to environmental concerns in that it does not use spray drying towers which typically emit particulates and volatile organic compounds into the atmosphere.
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 “granulating” refers to fluidizing agglomerates thoroughly for producing free flowing, round shape granulated-
Bolam Brian M.
Douyon Lorna M.
Miller Steven W.
The Procter & Gamble & Company
William Zerby Kim
LandOfFree
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