Drug – bio-affecting and body treating compositions – Anti-perspirants or perspiration deodorants
Reexamination Certificate
1999-10-06
2002-01-15
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Anti-perspirants or perspiration deodorants
C264S102000, C264S297800, C264S328160, C425S144000, C425S145000, C425S149000, C425S547000, C425S549000, C424S066000, C424S067000, C424S068000, C424S400000, C424S401000
Reexamination Certificate
active
06338840
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process and apparatus for forming a deodorant or antiperspirant composition, and particularly to compositions suitable for forming into sticks, to a process and apparatus for forming such sticks and to such sticks obtained thereby.
BACKGROUND AND PRIOR ART
Deodorant or antiperspirant sticks are conventionally manufactured by casting. In conventional casting processes, the constituents of a deodorant or antiperspirant stick composition are mixed in a large vessel, and heated to form a molten composition. Whilst the composition is in a mobile and readily pourable state, it is poured into the its container of the desired shape, which is sometimes called a barrel, and sometimes called a canister. Hereinafter, reference to a barrel includes reference to a canister. The composition is thereafter cooled until it solidifies. The barrel is either capped or bottomed, depending on whether bottom fill or top fill has been employed. If the barrel has been bottom filled, the bottom, including for example a mechanism for moving the stick along the barrel, is usually inserted whilst the composition is still sufficiently fluid or the mechanism defines an aperture through which the barrel can be filled.
There are several disadvantages associated with preparing a large volume of molten deodorant or antiperspirant composition for batch processing. The composition usually remains in a molten state for a long period, and particularly that towards the end of the batch. During this period, heat is dissipated, thereby increasing the overall energy consumption for the process. Secondly, the maintenance of a relatively high temperature needed to keep the composition molten for an extended period can not only cause the degradation of some common constituents, such as the oxidation of waxes or fats, resulting potentially in rancid odours that need to be masked by additional perfume, but also constrains the incorporation of heat sensitive constituents, such as any perfume itself, on account of the likelihood that they will be impaired before the sticks are formed. In addition, the conventional batch process is poorly suited to switching between different formulations in view of the time taken to cleanse the apparatus between batch preparations to avoid cross contamination.
One major problem associated with a casting process for deodorant or antiperspirant compositions is that they tend to shrink within the stick barrels as they cool. This is highly undesirable because shrinkage can adversely affect the visual appearance of the stick. Shrinkage can take the form of dimples, or voids, or a depression at the fill point of the stick. This problem becomes apparent particularly when the stick barrels are filled from the top. On the other hand, bottom filling of stick barrels is often more wasteful of material.
A second major problem arises because the composition must be kept mobile whilst it is being fed from its production/storage vessel to the filling station so as to avoid line blockage which would be extremely disruptive to production. In practice, this means that during the casting operation, the composition is usually introduced into the barrel at a temperature that is still significantly above its set temperature. As a consequence, the composition is likely to remain for a relatively long period of time within the barrel in a mobile state during which segregation can arise, particularly in respect of particulates, such as active antiperspirant materials, intended to be distributed reasonably evenly throughout the composition. Segregation is inherently undesirable for users of the stick, because its performance can vary depending on how much of the stick has been consumed.
Therefore, there is a need for a process and apparatus that is capable of forming deodorant or antiperspirant compositions into good quality sticks (i.e. sticks, for example, having a good appearance and physical characteristics) which overcomes or ameliorates one or more of the problems identified hereinbefore or disadvantages associated with the existing casting process.
In WO 94/28866, Gillette describes a modification of a conventional batch process for making antiperspirant sticks which avoids the formation of agglomerations of antiperspirant particles by controlling the processing temperature during the batch processing. Thereafter, they advocate that the stick composition is cooled to within the range of 1-10° C. above, and preferably, 1-4° C. above the solidification point of the solution suspending the antiperspirant and then poured into moulds. Whilst this modification may alleviate the formation of agglomerates of actives, it does not address various other aspects of a batch/pour mould method as indicated above.
In U.S. Pat. No. 4,722,836 to Geary et al, assigned to American Cyanamid Company, there is described an antiperspirant stick in which the segregation of an antiperspirant can be reduced by employing a material which has a surface area of at least 2m
2
/g by the BET method using nitrogen. This is of limited value to manufacturers of antiperspirant compositions in that the process is not applicable to any antiperspirant material having a surface area of below 2m
2
/g, and introduces an extra step into the manufacturing process, namely determining the surface area for all batches of material that are contemplated for use. Moreover, it does not address various other aspects of a batch/pour mould method as indicated above.
Apparatus and methods for injecting thermoplastics into moulds are known and used. For example, in U.S. Pat. No. 4,678,420 to Inoue, assigned to Inoue-Japax Research Inc, there is described apparatus in which a thermoplastic is fed through a hopper into a single screw mixer, plasticised and injected into a mould. Such apparatus and methods do not provide teaching that is directly applicable to deodorant or antiperspirant compositions, due to very different structuring mechanisms.
In U.S. Pat. No. 4,688,609 (Diaz) assigned to Fluid Packaging Company, there is described a system for automatically dispensing metered amounts of deodorant composition into stick barrels in which a large vat of molten deodorant composition is produced, and progressively delivered into stick barrels through dispensing apparatus injected at an operating pressure of 10-15 psi and within which the composition is maintained in a molten state by hot water jackets. The disclosure provides no teaching as to how to ameliorate or overcome the disadvantages of a batch manufacture process. Likewise, the document is silent about injection of a deodorant composition which is at least partially structured and another means to tailor an injection process to antiperspirant or deodorant compositions.
In U.S. Pat. No. 5,316,712 to Ono et al assigned to JO Cosmetics Co Ltd, there is described a process for producing solid cosmetics in which a cosmetic base containing a powder and oil is fed into a single screw which rotates within a heated chamber to mix and heat the constituents. The screw reciprocates within the chamber to inject the cosmetic base into a mould. The process is applied to producing cosmetics such as lipstick eye-shadow or foundation having an extremely high content of particulate materials such as talc or mica under high shear and very high pressure conditions without cooling to the vicinity of the set temperature of the cosmetic base. Such a combination of conditions is not applicable to the satisfactory injection moulding of deodorant or antiperspirant compositions.
The present inventors have found that some of the problems associated with the prior art processing of deodorant or antiperspirant compositions can be ameliorated or overcome by employing a continuous method for producing or dispensing a mobile feed of the deodorant or antiperspirant composition for supply to apparatus for dispensing the composition into stick containers.
The present inventors have also found that some or other problems associated with prior art processing of deodorant or antiperspirant compositions
Allan Peter Stewart
Bibby Elaine Susanne
Browne Michael Andrew
Langeveld Elfriede Maria
Lloyd Paul
Boxer Matthew
Dodson Shelley A.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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