Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-04-04
2004-05-04
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S446000, C510S475000, C134S025200
Reexamination Certificate
active
06730646
ABSTRACT:
The present invention relates to a composition for use in a dishwashing machine and a process for the use thereof.
Although modern dishwashing machines in most cases have numerous different washing programs, which differ with regards to the duration and temperature of the individual washing cycles, all washing programs essentially consist of the following basic steps: preliminary washing cycle, main cleaning cycle, one or more intermediate rinsing cycles, a clear rinsing cycle and drying. Whereas the machine dishwashing agent for bringing about the cleaning action is added at the start of the main cleaning cycle, during the clear rinsing cycle special agents are used, e.g. clear rinsing agents. Clear rinsing agents are intended to ensure that when washing with water water droplets are not left behind on the washed articles which, after drying on, leave behind marks of substances dissolved/dispersed in the droplets.
These two functionalities, namely the cleaning action of the machine dishwashing agent and the described function of a clear rinsing agent, have hitherto been brought about using two separate charging or dosing devices and products charged or dosed at different points during the dishwashing cycle.
Apart from the use of clear rinsing agents, there is still a need for further substances evolving their activity during the washing or rinsing cycle, such as e.g. an antibacterial activity (e.g. cationic compounds or triclosan), silver protection agents (e.g. benzotriazole), an odorous action (fragrances, perfume), bleaching action/disinfection (chlorine bleaches), odour masking (e.g. polyvinylpyrrolidone), anti-coating agents and enzymes for additional purposes (e.g. lipase for removing grease and fat deposits in the dishwasher). However, modern dishwashers have no suitable charging systems for this purpose.
The aim of the present invention was consequently to combine in a single function the cleaning function and the function or functions of the substance or substances to be added during the clear rinsing cycle with a constant efficiency compared with the results obtainable with a separate charging or to permit the charging of substances other than the clear rinsing agent in the clear rinsing cycle.
DE-OS 20 65 153 and 20 07 413 disclose detergent blanks for use as detergents, in which it is inter alia provided that two components having a different functionality are combined. The structure comprises an enveloping shell, which is e.g. formed from two shell halves comprising a cleaning agent, as well as a cavity enclosed by the shells and which contains additives such as softeners, brighteners, etc.
British patent 1 390 503 discloses a liquid detergent containing capsules, which are insoluble in the composition, but release their content if the composition is diluted with water. This objective is achieved in that the capsules are coated with a substance having a poor solubility in water solutions with high ionic strength, but becoming soluble if the ionic strength is reduced by dilution. It is pointed out that this procedure can be used to incorporate materials in the liquid cleaning agent, which are unstable in the latter or would produce an instability if added directly. It is also proposed that this procedure be used in order to delay the release of a specific substance. Reference is made to use in machine dishwashing agents and it is proposed for the encapsulation of tribromosalicylanilide in order to stabilize the latter. The encapsulated material is released within two minutes following the dilution of the cleaning agent with water, i.e. in the main cleaning cycle.
U.S. Pat. No. 4,082,678 describes a fabric conditioning product comprising a closed container containing a releasable agent, which is used to make water-insoluble or non-dispersible an inner container located in the container and which is normally water-soluble or water-dispersible, the inner container containing a fabric conditioner. The inner container is made from a substance, whose solubility in water is highly dependent on the ionic strength or the pH-value of the medium and the agent used for rendering the inner container insoluble is an agent for controlling the pH-value or ionic strength.
Japanese patent applications KOKAI 60-141705, 61-28440, 61-28441, 61-28596, 61-28597 and 61-28598 describe processes for the production of pH-sensitive microcapsules for use in detergents. The pH-sensitive coating is a copolymer of the following monomers:
A) at least one basic monomer of formula I:
in which R is hydrogen or a methyl group, R
1
and R
2
in each case an alkyl group with 1 to 3 carbon atoms and x an integer from 1 to 4,
B) at least one monomer, which is insoluble or difficultly soluble in water and
C) at least one water-soluble monomer.
It is stated that the polymers described are insoluble at a pH-value of 9.5 or higher and are soluble at a pH-value of 8.5 or lower. A description is given of different ingredients of cleaning agent compositions, which can be successfully and usefully coated with the polymers described. The aim of the invention described therein is that the substances only evolve their function during the rinsing cycle, protect the same up to the start thereof and then immediately release it. The use for dishwashing machines is not described.
A disadvantage of the solution described in these Japanese patent applications is that the enveloped particles are in direct contact with non-alkaline washing water at the start of the washing cycle which can lead to a partial dissolving of the protective envelope.
Japanese patent KOKAI 50-77406 discloses a washing aid surrounded by a water-soluble envelope obtained by mixing polyvinyl acetal dialkyl aminoacetate and at least one organic acid, which is solid at ambient temperature. This protective envelope serves to protect the washing aid during the main washing cycle and release it during rinsing cycles. The described compound reacts to a change of the pH-value between the main washing cycle and the rinsing cycle. The correspondingly enveloped particles are mixed with conventional pulverulent detergent. Here again the disadvantage of a possible partial dissolving of the protective envelope at the start of the washing cycle occurs.
European patent applications EP 284 191 A2 and 284 334 A2 disclose a water-soluble polymer film for the release of washing additives in the rinsing cycle of washing machines which, during the normal washing cycle, remains intact over a typical temperature range and rapidly dissolves in the rinsing cycle. It is pointed out that although the use of pH-sensitive coatings is known, said films are normally temperature-sensitive, so that they are not reliably stable during the different temperatures occurring in the washing cycle. The solution proposed is a pH-dependent material (which undesirably also has a positive temperature-dependent dissolving behaviour), which is combined with a material having a negative temperature-dependent dissolving behaviour. This combination is intended to guarantee that the coatings do not dissolve at the high temperatures at the start of the washing cycle (particularly the very high temperatures occurring in American machines). No reference is made to a use for machine dishwashing agents.
European patent application EP 481 547 A1 discloses multilayer machine dishwashing agent tablets with a core, a separating layer surrounding the core and an outer layer for the sequential release of the ingredients of the different layers. The aim of this tablet is to solve two different problems, namely 1) incompatible materials can be formulated together in a single tablet and released at different times in order to prevent mutual influencing and 2) compositions intended to evolve their functions at different times can be formulated in a single tablet.
One of the disadvantages of the prior art described in this document is that the only production process described is the successive moulding of the individual components. This leads to a risk of the core and/or core envelope being deformed, which
Carbonell Enric
Hertling Ludwig
Waschenbach Guido
Wiedemann Ralf
Wolf Natascha
Akin Gump Strauss Hauer & Feld L.L.P.
Douyon Lorna M.
Reckitt Benckiser N.V.
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