Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-10-16
2004-07-13
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S424000, C510S421000, C510S432000, C510S505000
Reexamination Certificate
active
06762159
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a detergent with excellent transparency stability and a polyglycerol fatty acid ester composition suited for use for such a detergent.
Liquid detergents need to remain free from separating or precipitation of the constituents and be capable to maintain transparency stability, or the ability to remain transparent for a prolonged period of time, when placed under various environmental conditions in the market, especially in a cold district.
Japanese Patent Application Laid-Open (KOKAI) No. 6-340896 discloses a detergent containing an alkylene oxide adduct of a short-chain alcohol as a liquid detergent with improved transparency stability.
Polyglycerol fatty acid esters are a very mild surface active agent showing high performance in surface tension, emulsification, solubilization and foaming as well as high detergency, harmless to the human body and also little stimulant to the skin and hair, so that they are suited for cleaning foods, processed food materials, food producing equipment, tableware and such and actually used as a primary constituent of detergent compositions such as shampoo, body shampoo, cleanser, etc.
For instance, as a polyglycerol fatty acid ester with improved foaming ability, one containing not less than 70% of a fatty acid monoester obtained from an addition polymerization reaction of glycidyl and a fatty acid is known (Japanese Patent Application Laid-Open (KOKAI) No. 8-109153, EP 0758641 A1).
The hitherto known detergents containing a polyglycerol fatty acid ester, however, are still unsatisfactory in their ability to retain transparency, and the development of a detergent with high transparency stability has been desired.
SUMMARY OF THE INVENTION
In view of the above, the object of the present invention is to provide a transparent detergent which is capable of maintaining excellent transparency stability even if kept in storage for a long time, gives a good image as a commercial product, and is assured of high safety and thus anticipated to obtain high appraisal in the market.
As a result of the present inventors' earnest study, to solve the above problem, it has been found that such a detergent can be realized by using a polyglycerol fatty acid ester composition having a specific cloud point as a surface active agent.
In a first aspect of the present invention, there is provided a detergent which comprises an aqueous solution containing not less than 2% by weight of a polyglycerol fatty acid ester and which is capable of remaining transparent for one week or more at 5° C.
In a second aspect of the present invention, there is provided a detergent comprising a polyglycerol fatty acid ester composition whose cloud point as determined in an 8 wt % sodium sulfate solution in a concentration of 1% by weight is not lower than 40° C.
In a third aspect of the present invention, there is provided a detergent as defined in the above first aspect or second aspect which is to be used for foods.
In a fourth aspect of the present invention, there is provided a polyglycerol fatty acid ester composition whose cloud point as determined in an 8 wt % sodium sulfate solution in a concentration of 1% by weight is not lower than 40° C., and which composition contains not less than 0.1% by weight of soap.
The polyglycerol fatty acid ester compositions whose cloud point as determined in an 8% sodium sulfate solution in a concentration of 1% by weight is not lower than 40° C. are already known in the art as an emulsion stabilizer for foods, but their use for detergents is novel.
DETAILED DESCRIPTION OF THE INVENTION
The detergent according to the present invention is an aqueous solution which comprises not less than 2% by weight of a polyglycerol fatty acid ester and which is capable of remaining transparent for one week or more at 5° C.
The polyglycerol fatty acid ester (which may hereinafter be referred to as “PoGE”) used in the present invention is an ester obtainable by reacting usually polyglycerol (which may hereinafter be referred to as “PoG”) and a fatty acid. In the said polyglycerol fatty acid ester, the average degree of polymerization of the constituent polyglycerol is usually 4 to 20, preferably 8 to 14. The fatty acid forming another constituent of the ester is usually selected from the saturated or unsaturated fatty acids having 8 to 22 carbon atoms in the molecule, but it is preferably a saturated fatty acid having 8 to 14 carbon atoms in the molecule. Examples of such fatty acids include caprylic acid, capric acid, lauric acid and myristic acid, among which lauric acid is preferred. These fatty acids may be used as a combination of two or more depending on the purpose of use of the composition. The greater the content of the monoester, the more desirable. The average esterification degree is usually 1 to 1.5, preferably 1.
In the aqueous solution according to the present invention, usually water is used as medium, but it is possible to use a mixture of water and an alcohol such as ethanol, ethylene glycol, glycerin, propylene glycol or the like as medium. In case of using a mixture of water and an alcohol, their mixing ratio is not subject to any specific restrictions, but usually the content of water in the medium is not less than 70% by weight, preferably not less than 80% by weight, more preferably not less than 90% by weight.
The content of the polyglycerol fatty acid ester in the detergent is not less than 2% by weight. The content defined herein (not less than 2% by weight) is the content of the ester proper and does not indicate the content of the polyglycerol fatty acid ester composition which includes impurities such as the unreacted materials. The ester content is usually not more than 20% by weight, preferably not more than 15% by weight, more preferably not more than 10% by weight. Below 2% by weight, the content of the surface active agent (polyglycerol fatty acid ester) is too low to produce the desired detersive effect. It is to be also noted that supplementation of other surface active agent than a polyglycerol fatty acid for maintaining the detersive effect may prove detrimental to the safety of the composition. An ester content in excess of 20% by weight is also undesirable as it tends to induce precipitation.
“which is capable to remain transparent for one week or more at 5° C.” means that the detergent can remain transparent for more than a week when it is allowed to stand at 5° C. immediately after its preparation. “Being transparent” means that the transmittance of the whole detergent is almost 100%, and such “transparent detergent” does not include one which forms a precipitate at the bottom of the container. The period in which the detergent can remain transparent is preferably not less than 50 days, more preferably not less than 100 days, even more preferably not less than 150 days. It is considered that if the preparation can remain transparent for more than a week at 5° C., it can well maintain high transmittance for a long time even in a cold district. On the other hand, in the case of a detergent which is not transparent from the time of its preparation or a detergent which can not keep transparency even for a week at 5° C., it is considered that such a detergent is liable to precipitate heavily at the bottom of the container if it is stored for a long time in a cold district. In such a case, the user may hold doubt about safety and cleaning ability of the detergent, and also the image of the detergent as a commercial product will be impaired from the aesthetic point of view.
The content of soap in the detergent of the present invention is not less than 0.01% by weight. A soap content of not less than 0.01% by weight is preferable as it helps better transparency stability of the detergent. This is attributable to the fact that since the soap molecules are trapped in the micells formed by the polyglycerol fatty acid ester, the negative charge carried by the soap molecules is given to the micells to generate a static repulsion which discourages aggregation or uniting of
Conlin David G.
Edwards & Angell LLP
Hazzard Lisa Swiszcz
Mitsubisi Chemical Corporation
Ogden Necholus
LandOfFree
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