Title:  Internal liquid composition contained as internal liquid in a releasing container and releasing container product

United States Patent:  6,258,857

Assignee:  Kyowa Industrial Co., Ltd. (Osaka, JP)

Filed:  February 4, 1999

The invention relates to an internal liquid composition contained in a releasing container such as an aerosol container, and a releasing container product containing such composition. The following three types are proposed as the composition. The first type is a blending of inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, and alkali. The second type is a blending of inorganic porous fine particles carrying a chemical, disperse solution, and synthetic resin fine particles. The third type is a blending of inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, alkali, and synthetic resin fine particles. As inorganic porous fine particles, for example, silicic anhydride porous fine particles may be used. The chemical to be carried by the inorganic porous fine particles includes perfume, insect repellent, agricultural chemical, deodorant, plant extract, ultraviolet blocker, antioxidant, antipruritic, hair growth promoter, vitamin, antiperspirant, sunburn remedy, antiseptic, moisturizer, styptic, oil, and others. As disperse solution, water, alcohol, ether and other organic solvents may be used.

BRIEF SUMMARY OF THE INVENTION

The present inventors made various investigations in order to solve the above problems, and hence discovered the following three compositions, as the internal liquid composition to be contained in an aerosol container as the internal liquid in a releasing container.

The first internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, and alkali.

The second internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, and synthetic resin fine particles.

The third internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, alkali, and synthetic resin fine particles.

The inventors further invented releasing container products containing these first, second and third internal liquid compositions.

The first internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, and alkali. In this internal liquid composition, by the thickening action and pH adjustment obtained by the acrylic acid polymer and alkali, the inorganic porous fine particles carrying the chemical can be uniformly dispersed in the disperse solution. Moreover, when the disperse solution is evaporated after releasing onto the object, a film of the acrylic acid polymer can be formed on the surface of inorganic porous fine particles, and dissipation of the carried chemical is delayed, so that the sustained-release effect can be enhanced.

The second internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, and synthetic resin fine particles. The inventors discovered that the dispersion and re-dispersion performance of inorganic porous fine particles can be enhanced and that lowering of dispersion performance of inorganic porous fine particles due to propellant can be prevented by introducing fine particles of other material (that is, synthetic resin particles) capable of preventing collision among these fine particles in the group of inorganic porous fine particles such as group of silicic anhydride fine particles, and thereby completed the second internal liquid composition of the invention.

More specifically, in the course of various experiments about the first internal liquid composition of the invention, the inventors noticed that the re-dispersion of the inorganic porous fine particles was lowered as the content of carbon dioxide as propellant in the aerosol product was increased. A superficial cause is changes of pH of the internal liquid due to filling with carbon dioxide. The relation between the pH changes and lowering re-dispersion is estimated as follows. That is, the electric charge on the surface of fine particles is considered to have an action to prevent collision between fine particles. This is because fine particles of positive (+) and negative (-) polarity attract each other by the electrostatic repulsion of electric charge of same polarity. For example, when silicic anhydride fine particles are used as inorganic porous fine particles, the acidity of the internal solution is increased by filling with carbon dioxide and the concentration of hydroxide ions in the internal solution is lowered in the disperse solution of water or alcohol, and silicic ions are also decreased. When the concentration of the remaining silicic ions is lowered, the electric charge on the surface of fine particles decreases. As a result, the electric charge on fine particles is insufficient, and collision between fine particles cannot be prevented.

Accordingly, when both silicic anhydride fine particles and synthetic resin fine particles are coexistent in the disperse solution, frictional charging hardly occurs between the both fine particles, and since charging of the two is both negative (-), so that collision between fine particles can be prevented. At this time, the particle size of the synthetic resin fine particles is preferred to be same as the particle size of silicic hydride porous fine particles, or larger than the particle size of silicic hydride porous fine particles. That is, by decreasing the particle size of silicic hydride porous fine particles which are more likely to have effects of pH, and increasing the particle size of organic synthetic resin fine particles which are less likely to have effects of electric charge by pH, the behavior between fine particles by electric charge is dominant, and therefore it is considered that collision between fine particles can be prevented by the electric charge.

The third internal liquid composition of the invention comprises inorganic porous fine particles carrying a chemical, disperse solution, acrylic acid polymer, alkali, surface active agent, and synthetic resin fine particles, and it exhibits the actions of both first and second internal liquid compositions.

Claim 1 of 6 Claims

What is claimed is:

1. An internal liquid composition contained in a releasing container as an internal liquid, comprising inorganic porous fine particles carrying a chemical, a disperse solution, and synthetic resin particles, wherein said inorganic porous fine particles are at least one kind selected from the group consisting of non-hollow porous silica spherical fine particles and hollow porous silica spherical fine particles, and the inorganic porous fine particle size is 0.5 to 50 microns, mean particle size is 0.5 to 30.0 microns, surface pore diameter is 20 to 150 angstroms, specific surface area is 20 to 800 m² /g, and pore volume is 0.01 to 1.50 ml/g.

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