Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-12-20
2002-08-06
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S220000, C510S439000, C264S037100, C264S114000, C264S140000
Reexamination Certificate
active
06429185
ABSTRACT:
The present invention relates to a process for producing a powder from packaged detergent tablets, especially those adapted for use in washing.
Detergent tablets are widely used in different types of washing or cleaning applications. In auto dish washing application, such tablets are produced from an original highly compressed powder having a given chemical composition, whereby the highly compressed tablet is not sensitive to mechanical stress because it is solid, and whereby the tablet readily dissolves in the dish washing machine for producing the aqueous solution comprising surfactants. In the production process of such tablets, it may occur that a low proportion of the tablet produced are not suitable for use, for example because of a non adequate chemical composition, or because of breakage on the line. In such a case, the tablets which are not suitable for use are typically recycled by crushing and dissolving the not suitable tablets to form a solution, so that a powder may be obtained from this solution, this powder being added in small proportion to the original powder to be compressed again for making tablets suitable for use.
This process is further complicated in cases of use of packaged tablets, whereby such tablets may be used also for producing powder, and whereby it should be avoided that the powder obtained contains pieces of the package. The aim is then to selectively separate the package from its content, i.e. the tablet, to avoid contamination of the obtained powder by remains of package.
The present invention concerns a process for producing a powder from a packaged tablet, the package comprising plastic materials.
Among the advantages of such a process is that it can be used for reducing waste in the environment while maintaining a satisfactory quality for the tablets to use.
While having these and other advantages, existing processes for producing a powder from a tablet, particularly the processes used for recycling auto dish washing tablets, have disadvantages. For example, such a process does not apply to the separation of the package from the tablet in cases where the tablet is packaged prior to being processed.
The invention seeks to provide a process of the above mentioned kind which allows to obtain a recycled powder which is not contaminated by packaging residues.
SUMMARY OF THE INVENTION
In accordance with the invention, this object is accomplished in a process of the above kind in that it comprises a first step of submitting the packaged tablet to mechanical degradation with first mechanical degradation means, a second step of sifting with first sifting means to obtain an intermediate material, a third step of submitting the intermediate material to mechanical degradation with second mechanical degradation means, and a fourth step of sifting with second sifting means to obtain the powder, whereby the powder obtained comprises less than 0.05% per weight of plastic material.
A process in accordance with the invention has a number of advantages. Since the recycling of the tablet is made using mechanical agitation and sifting, the recycled powder can be obtain without passing by a dissolution step, although it could be preferred to add such a step in particular conditions. Furthermore, the combination of the four steps allows to minimise the amount of plastic material contained in the obtained powder.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a process for producing a powder from a packaged tablet. In a preferred embodiment according to the invention the tablet is having a tensile strength of at least 5 kPa, preferably the tensile strength is of at least 10 kPa, more preferably of at least 15 kPa and even more preferably of at least 20 kPa, so that the tablet is sufficiently mechanically resistant while dissolving readily. The tablet also preferably comprises surfactants, more preferably at least 2% by weight of surfactants. In a preferred embodiment according to the invention, the tablet comprises at least 10% by weight of surfactants, more preferably at least 15% and most preferably at least 20%. Indeed, the invention more particularly relates to laundry tablets, laundry tablets having a particularly high level of surfactant. The process according to the invention comprises a first step, whereby the tablet is submitted to mechanical degradation. Mechanical degradation may be obtained via different means, the preferred means for mechanical degradation being provided by centrifugation, preferably by use of a centrifugal sifter, in particular a KEK centrifugal sifter from KEMUTEC, preferably a K650. The second step of the process consists in sifting to obtain the intermediate material. Indeed, after having been submitted to mechanical degradation, the packaged tablet is not a solid block but consists in a plurality of grains or package pieces. Sifting allows to select a part of these grains or package pieces. In a preferred embodiment according to the invention, sifting in the second step is obtained by a mesh having a plurality of 8 mm diameter apertures. Preferably, the mesh size is comprised between 2 and 15 mm, more preferably between 5 and 12 mm, and most preferably between 6 and 10 mm. The rest of the grains or package pieces which is does not sift through is evacuated and is not comprised in the intermediate material. Typically, the rest of the grains or package pieces which are not submitted to the second step represents less than 1% per weight of the whole grains or package pieces. Most of this rest is formed from plastic materials. This rest is preferably not re-inserted directly at the start of the process according to the invention, but may be submitted to an extra treatment. According to the invention, the intermediate material is thereafter submitted to a third step similar to the first step, and to a fourth step similar to the second step. Preferred for the fourth step is use of a nylon sieve having apertures having a diameter comprised between 2.4 and 3.5 mm. Preferably, the mesh size or the diameter of the apertures is comprised between 1 and 6 mm, more preferably between 1.5 and 5 mm, and most preferably between 2 and 4 mm. Similarly, a part of the intermediate material is sifted, the other part being rejected. According to he invention, it was found that use of such a process allows that the obtained powder comprises less than 0.05% per weight of plastic material, preferably less than 0.03% per weight, more preferably less than 0.02%, and most preferably less than 0.01%.
In a preferred embodiment according to the invention, the intermediate material is such that it comprises less than 5% per weight of particles passing through a 150 micrometer sieve, the obtained powder being such that it comprises less than 6% per weight of particles passing through a 150 micrometer sieve. In a preferred embodiment, the obtained powder is such that it comprises less than 5% preferably less than 4% per weight of particles passing through the 150 micrometer sieve. It should be noted that the 150 micrometer sieve referred to is normally different from the sieving means used in the second step according to the invention, and that it is mentioned in the purpose of providing means for analysing the granular structure of the obtained powder or intermediate material. The minimisation of the level of fine particles allows to improve the sanitary and environmental characteristics of the obtained powder. This more particularly applies to a tablet comprising enzymes, whereby it is preferred that the enzymes components of the tablet are not broken up during the process. Breaking up of percarbonate components should also be avoided, as the stability of the finished product could be affected. Indeed, typically tablets according to the invention would be tablets which require being packed in order to stabilise their chemical evolution thanks to specific characteristics of the package, as described in the EP application of the applicant number 97202674.4 now WO99/11540. Indeed, in a preferred embodiment, the invention relates to a tablet compr
Ollero Novo Maria del Mar
Van Dijk Paul Irma Albertus
Vega Jose Luis
Douyon Lorna M.
Dressman Marianne
Miller Steven W.
William Zerby Kim
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