Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-05-28
2001-09-25
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...
C510S139000, C510S395000, C510S438000, C510S444000, C510S475000, C510S507000, C510S511000, C424S489000, C134S042000
Reexamination Certificate
active
06294509
ABSTRACT:
TECHNICAL FIELD
The present invention relates to disintegrating particles and a cleaner or detergent composition containing the same, and more particularly to disintegrating particles which disintegrate during cleansing and rinsing, thereby causing little damage to and itchiness of the skin. A cleanser or detergent composition which contains the disintegrating particles has outstanding physical (mechanical) cleaning capability, and has excellent rinsability properties because the particles readily disintegrate during rinsing.
BACKGROUND ART
In recent years, various kinds of rinse-out type skin cleansers (facial soap, body soap, massaging cream and solid soap) have been marketed and used. The reasons for the success of these products is that they provide users with a fresh clean feeling after use and moreover have the desirable property that excess keratin (dirt), clogged skin pores, and the like, which are difficult to remove with the conventional cleanser compositions, can be washed out by virtue of the physical cleansing effects of the rinse-out type skin cleansers.
Controlling the particle diameter and hardness of a scrubbing cleanser in view of problems of irritation to the skin and skin roughness has also been investigated, in order to develop a cleanser having high cleanability that causes little skin irritation (Japanese Patent Application Laid-Open No. 151693/1990).
On the other hand, cleanser compositions have been proposed to achieve high physical detergency and to smoothly finish the skin by incorporating particles of sodium chloride in a proportion not lower than its saturated solubility in the cleanser composition (Japanese Patent Application Laid-Open No. 305951/1994). Other cleanser compositions have been proposed that are intended to achieve high physical detergency and to smoothly finish the skin by incorporating particles of a water-soluble inorganic salt in the cleanser composition and dissolving potassium chloride and magnesium chloride therein with the object of stabilizing the resulting dispersion (Japanese Patent Application Laid-Open No. 208455/1996).
However, the cleanser compositions comprising the scrubbing cleanser wherein the particle diameter and hardness have been controlled still have problems because they leave a feeling of mixed foreign matter upon massaging, and it is difficult to rinse out afterwards.
The cleanser composition in which the particles of sodium chloride are incorporated in a proportion not lower than its saturated solubility have the problems of dispersion stability and dispersibility of individual components including the scrubbing cleanser (scrubber), since the scrubber tends to cause agglomeration and sedimentation. In addition, since sodium chloride is incorporated in a proportion not lower than its saturated solubility, the composition is undesirable because its foamability is extremely reduced upon cleansing, and so its cleaning ability and skin feeling are deteriorated.
On the other hand, in the cleanser composition in which potassium chloride and magnesium chloride are incorporated in addition to the above-described particles of the water-soluble inorganic salt, the agglomeration and sedimentation of the scrubber are improved. However, since the water-soluble inorganic salt is incorporated in a proportion not lower than its saturated solubility, the composition undesirably has a reduced foamability upon cleansing, and so its cleaning ability and skin feel are deteriorated.
DISCLOSURE OF THE INVENTION
One object of the invention is to provide a cleansing composition having high detergency and gives users a pleasant feeling upon use. Another object is to provide a cleansing composition that does not cause damage to and itch on the skin. Another object of the present invention is to provide a cleansing composition having extremely good rinsability because the disintegrating particles are easily disintegrated by either rinse or tears.
These and other objects are achieved by providing disintegrating particles formed by agglomerating primary particles at least part of which are insoluble in water (hereinafter referred to as “disintegrating particles”), wherein the agglomeration of the disintegrating particles disintegrates in an aqueous solution containing a water-soluble salt by lowering the concentration of the water-soluble salt.
According to the present invention, there is also provided a cleanser composition that contains the disintegrating particles, a water-soluble salt, a surfactant and water, wherein the concentration of the water-soluble salt is lower than its saturated solubility.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Other features of the invention will become apparent in the following description of preferred embodiments, which are given for illustration of the invention and are not intended to be limiting thereof.
The disintegrating particles according to the present invention are agglomerated particles formed by agglomerating primary particles at least part of which are insoluble in water, and are such that the agglomeration thereof is disintegrated in an aqueous solution containing a water-soluble salt by lowering in the concentration of the water-soluble salt, namely their rate of disintegration is higher in the case where the concentration of the water-soluble salt is low compared with the case where the concentration is high.
No particular limitation is imposed on the primary particles for forming the disintegrating particles according to the present invention so far as at least a portion of the particles is insoluble in water. Preferable examples thereof include water-insoluble primary particles and a combination of water-insoluble primary particles and water-soluble primary particles. These primary particles may be either organic particles or inorganic particles. The term “water-insoluble” as used herein means that the solubility of the subject particles is lower than 50 wt. %, when 1 part by weight of the particles are dissolved in 99 parts by weight of water, while the term “water-soluble” means that the solubility under the same conditions as described above is at least 50 wt. %. Preferably, the solubility is calculated out from a solids content in a filtrate obtained by filtering the aqueous solution through filter paper (No. 2). The water-soluble primary particles are preferably those such that the solubility is at least 90 wt. %.
Examples of the water-insoluble organic primary particles include primary particles of synthetic polymers, such as polyethylene, polypropylene, polyamide, polyethylene terephthalate, polystyrene, polyurethane, sodium poly(meth)acrylate, poly(meth)acrylic esters, rubbers such as ethylene rubber, propylene rubber, styrenebutadiene rubber, butadiene rubber and silicone rubber, and crosslinked products thereof; and natural polymers such as cellulose and derivatives thereof, chitosan and derivatives thereof, starch and fruit shells, and derivatives thereof. Among these, the primary particles of polyethylene, polyamide, polystyrene, sodium poly(meth)acrylate, poly(meth)acrylic esters, cellulose and derivatives thereof, and starch are preferably used.
Examples of the water-insoluble primary particles include primary particles of bentonite, talc, mica, kaolin, sepiolite, silica, calcium carbonate, titanium oxide, silicic acid anhydride, hydroxy calcium apatite and pearl powder. Among these, bentonite, talc, mica, kaolin and silica are preferably used.
These water-insoluble primary particles may be in any form of true sphere, substantial sphere and irregular shapes formed by grinding or the like. Hollow or porous particles may also be used. These water-insoluble primary particles may be used either singly or in any combination thereof.
As the water-soluble organic primary particles, there may be used primary particles of synthetic products such as polyvinyl alcohol and derivatives thereof, alkali salts of poly(meth)acrylic acid, alkali salts of (meth)acrylic acid/(meth)acrylate copolymers, alkali salts of acrylic acid/maleic acid copolymers, and polyvinyl pyrrolidone; s
Hanazawa Hideyuki
Hasebe Yoshihiro
Matsumoto Tatsuki
Meiwa Zenbei
Nakamura Mamoru
Douyon Lorna M.
Kao Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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