GB2385790A - Anitmicrobial silver-chloro agents - Google Patents

Abstract

An antimicrobial agent includes silver-chloro complex salts and chloride, and further oxidizing agents such as sodium hypochlorite or sodium chlorite. The antimicrobial agent includes the silver-chloro complex salts and chloride, and further a compound, such as alcohols or surfactants, which has compatibility with a solvent such as water which dissolves the chloride. The antimicrobial agent has immediate effect and cleansing ability without causing rust or deposition of salts in use. Further, the antimicrobial agent includes the silver-chloro complex salts, and chloride, such as polyaluminium chloride or benzalkonium chloride, which has at least (I) a property capable of existing as a supersaturated aqueous solution in the presence of a crystal nucleus at least at room temperature for 24 hours or longer and (II) a property capable of being decomposed when dissolved in water.

Description

- - 1 _ 2385790

ANTIMICROBIAL AGENTS

FIELD OF THE INVENTION

The present invention relates to an antimicrobial agent, detergent, laundry supplement, disposable sheets, and disposable sheet set, and a producing method of the antimicrobial agent, and an antimicrobial treatment method. Particularly, the invention relates to an antimicrobial agent used to apply antimicrobial treatment such as disinfection (sterilization), deodorizing, mildew proofing, and sanitization on target objects such as houses, hospitals, public facilities, industrial products, industrial wastes, and home appliances, and a producing method of such an antimicrobial agent, and an

- 2 antimicrobial treatment method for treating the target objects with the antimicrobial agent, and the invention also relates to a detergent and laundry supplements used to wash fiber products of, for example, clothes, bedding, and medical use among various other products, and an antimicrobial treatment method for treating target objects such as these fiber products, and also disposable sheets and a disposable sheet set suitable for use in beds of permanently-ill patients.

BACKGROUND OF THE INVENTION

In recent years, in-hospital infections by MRSA (Methicillin-resistant Staphylococcus aureus), or infections by the enteropathogenic bacteria Escherichia cold (O- 157) and other bacteria have become such a serious social problem that there is strong need for counter-measures against these infections. Further, with increase in number of air-tight housing, such as apartments, there has been high demand for mildew proofing in places where humidity is high, such as bathrooms. Conventionally, for disinfection to prevent infections in hospitals and houses, it has been common practice to adopt chlorine-containing disinfectants such as sodium hypochlorite, sodium chlorite, sodium

dichloroisocyanurate, and sodium trichloroisocyanurate, or quaternary ammonium salts such as benzalkonium chloride. In particular, chlorinecontaining disinfectants have such superior properties as demonstrating the disinfecting effect on eumycetes and various species of bacteria except tubercle bacillus, having wide disinfecting spectrum and thus can deactivate viruses, having immediate effect, preventing resistant bacteria, capable of oxidative decomposition of odor components in addition to and at the same time as disinfection, and converting itself after decomposition to sodium chloride or urea which is safe, and thus the chlorine-containing disinfectants have been most commonly used among other disinfectants. However, the chlorine-containing disinfectants have such drawbacks as not showing the residual effect, and failing to inhibit proliferation of air-borne microbes which were newly introduced after the treatment, which necessitated repeating the treatment quite often.

Further, with regard to the quaternary ammonium salts, while their disinfecting properties are similar to that of the chlorine-containing disinfectants, they are incapable of decomposing odor components and react with common anionic surfactants and deactivate itself, and

- 4 thus had the problem of limited use compared with the chlorinecontaining disinfectants.

Meanwhile, conventionally used antimicrobial agents having a long-term and sustained effect on bacteria and molds have incorporated ions of heavy metals such as zinc, silver, and copper. The heavy metal ions have such properties as having a wide disinfecting spectrum, showing strong disinfecting effect in particular on bacteria, having long-term and sustained antimicrobial effect, and preventing resistant bacteria. As such heavy metal ions, silver ion has been widely used recently since it is superior especially in safety.

However, the silver ion is insufficient compared with oxidizing agents such as chlorine-containing disinfectants when it comes to disinfecting effect and deodorizing effect immediately after the treatment, and in order to effect the mildew proofing properties, the silver ion needs to have a higher concentration than the case for bacteria. There is a further problem in silver ion in that when sulfides exist in the target object (object to be treated), the silver ion converts itself to sulfide which is water insoluble, with the result that the antimicrobial effect suffers significantly in subsequent treatment.

In view of these drawbacks, the inventors of the

- 5 - present invention studied to develop antimicrobial agents having a wide disinfecting spectrum, capable of preventing resistant bacteria, having good safety, having both immediate and residual effects with respect to disinfection as well as deodorizing, and having good resistance for the sulfide, by combining the oxidizing agents having the immediate effect and the silver ion having the residual effect.

According to the study by the inventors of the present invention, the silver ion, when combined with the oxidizing agents, preferably exists in the aqueous solution state. The silver ion may be kept in the solution state by conventionally known methods such as turning silver ion into complex salts of thiosulfate or thiocyanate, or into silver salts of amino acids.

However, the anionic ions of thiosulfate, thiocyanate anion, or amino acids, when mixed with the oxidizing agents, are decomposed by the oxidizing effect of the oxidizing agents with the result that the active ingredient, the silver ion, precipitates as hydroxides, which prevented the complex salt of silver thiosulfate, thiocyanate complex salt of silver, and silver salts of amino acids from being mixed with the oxidizing agents.

Further, in recent years, there have been proposed many fiber products such as clothes and other various

- 6 - bacteria-proof products which have been subjected to the antimicrobial treatment (including sanitization and sterilization). Generally, these bacteria-proof products come to have antimicrobial properties by the solid (powder) antimicrobial agents which are pre-fixed on the surface and elsewhere of the fiber products. As such solid antimicrobial agents, organic antimicrobial agents which are hardly soluble in water, or hardly water-

soluble compounds of metals such as silver having antimicrobial properties have been used.

Meanwhile, liquid or water-soluble antimicrobial agents have been put to practical applications as well.

As such liquid or water-soluble antimicrobial agents, alcohols, phenols such as cresol, and quaternary ammonium salts, as well as complex salts of antimicrobial metal such as silver salts of amino acid, thiosulfate, and thiocyanate have been used.

However, the bacteria-proof products (fiber products, etc.) which were treated with the conventional antimicrobial agent lose their antimicrobial properties when their surface is covered with dirt, etc. Further, when silver compounds are used as the antimicrobial agent, the antimicrobial properties are lost when the silver is sulfidized.

Also, the conventional solid antimicrobial agent

needs to be fixed on the surface and elsewhere of the products by prekneading or other special treatment.

Thus, once the antimicrobial properties of the product are lost, for example, by dirt or sulfidization of the silver, an industrial-scale treatment technique is required to recover the antimicrobial properties by treating the product again. Thus, with the antimicrobial treatment method by the conventional solid antimicrobial agent, it was difficult to sustain the antimicrobial properties of the bacteria-proof products or recover the antimicrobial properties by re-treatment of the products conveniently at home.

In contrast, the conventional liquid or water-

soluble antimicrobial agents have the advantage that the antimicrobial properties can be effected by directly applying the agents on the surface of the products in use. However, these liquid or water-soluble antimicrobial agents applied on the surface of the fiber products completely dissolve into water by washing and the antimicrobial properties are easily lost.

Further, the antimicrobial agents of alcohols or phenols have the problem that a sustained antimicrobial effect cannot be obtained since they are volatile and easily oxidized. Also, the antimicrobial agent of alcohols in particular are highly inflammable, and the

- 8 antimicrobial agent of phenols are very toxic and has strong irritating odor, and therefore they have the problem of safety. Further, the antimicrobial agent of quaternary ammonium salts has the drawback that the antimicrobial ability is easily lost by reacting with an anionic surfactant which exists in a common detergent.

Further, the thiosulfate complex salt and thiocyanate complex salt of silver include sulfide ion (S2-) in the complex salt, and generate toxic gas when decomposed by acid or heat, and the complex salt as the active ingredient gradually converts itself to silver sulfide, thus losing the antimicrobial ability.

Incidentally, the thiosulfide complex salt of silver, thiocyanate complex salt of silver, and amino acid salt of silver are decomposed in the presence of alkaline oxidizing agents such as sodium hypochlorite by the oxidizing effect of the sodium hypochlorite, etc. Thus, the conventional silver-containing antimicrobial agents utilizing the complex salts of silver could not be used with so-called chlorine-containing bleaching agents containing the alkaline oxidizing agents such as sodium hypochlorite. Further, the organic complex salts such as amino acid salts of silver have relatively low complex stability compared with inorganic complex salts including

- 9 - sulfide ion (S2-). Thus, the silver chloride tends to form precipitates during storage by the reaction with surrounding chlorine ions with the result that the antimicrobial properties suffer significantly. Also, the precipitates of the silver chloride thus formed gradually increase in size during storage of the detergent, etc. Such precipitates of the silver chloride have poor solubility and are not dispersed homogeneously, and thus do not have the property of being absorbed onto the surface of the products. Thus, the precipitates of the silver chloride which are formed by the reaction of the organic complex salts such as amino acid salts of silver with the surrounding chlorine ions hardly contribute to effect the antimicrobial properties. Further, these organic complex salts may blacken in the same manner as inorganic silver slats and may result in change in color of the fiber products.

Incidentally, in order to eliminate the inconvenience of washing sheets, disposable sheets have been used for the sheets of beds of permanentlyill patients. However, conventional disposable sheets are realized by the use of inexpensive raw materials such as paper or unwoven fabric, and while this may eliminate the inconvenience of washing the sheets, the inconvenience of

- 10 replacing the sheets could not be eliminated. The conventional disposable sheets necessitated a permanently-ill patient to be moved from the bed to replace the sheets. Thus, replacement of the conventional disposable sheets generally required a plurality of care givers and it was very difficult to replace the sheets by a single care giver. Therefore, there were cases where the disposable sheets could not be replaced even when it was urgently needed due to dirt on the sheet because there was only one care giver.

Accordingly, there is demand for disposable sheets which can be replaced by a single care giver.

DISCLOSURE OF INVENTION

The present invention was made in the light of the foregoing problems and it is the first object of the present invention to provide an antimicrobial agent in which oxidizing agents and silver ion coexist, and which has a wide disinfecting spectrum, prevents resistant bacteria, has good safety, shows high resistance to sulfides, and has both immediate and residual properties for disinfection as well as deodorizing, and to provide a producing method thereof, and an antimicrobial treatment method using such an antimicrobial agent.

In order to achieve the first object, a first

- 11 -

antimicrobial agent in accordance with the present invention includes silver-chloro complex salts and oxidizing agents.

With this constitution, it is possible to provide an antimicrobial agent having both immediate and residual properties for disinfection and deodorizing, having a wide disinfecting spectrum, capable of preventing resistant bacteria, having good safety, capable of maintaining sufficient stability even in a medium or environment in which sulfides coexist, and having a reasonable price, and having superior deodorizing action and antimicrobial and mildew proofing action.

It is preferable that the first antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and oxidizing agents in an aqueous solution of chlorides, and the concentration of the silver-chloro complex salts in the aqueous solution of chlorides is not less than 0.05 mg/1 in silver ion equivalent concentration. This allows the antimicrobial agent to demonstrate the antimicrobial action sufficiently. The concentration of the silver-chloro complex salts in the aqueous solution of the chlorides is preferably not less than 2.5 mg/1 in silver ion equivalent concentration. As a result, it is possible to obtain

- 12 superior antimicrobial action even in the presence of organic substances which contain sulfur in the form of sulfides. The concentration of the chloride ion in the aqueous solution of the chlorides is preferably not less than 0.02 mol/l. As a result, the silver ion concentration of not less than 2.5 mg/l can be realized. Thus, superior antimicrobial action can be obtained even in the presence of organic substances which contain sulfur in the form of sulfides. The oxidizing agents are preferably sodium hypochlorite and/or sodium chlorite. As a result, the immediate property of the antimicrobial agent can further be improved.

Further, in order to achieve the first object, a producing method of the first antimicrobial agent in accordance with the present invention is adapted to mix an aqueous solution of chlorides, silver and/or silver compound, and oxidizing agents.

With this method, it is possible to provide a producing method of the antimicrobial agent having both immediate and residual properties for disinfection and deodorizing, having a wide disinfecting spectrum, capable of preventing resistant bacteria, having good safety, capable of maintaining sufficient stability even in a

- 13 -

medium or environment in which sulfides coexist, and having a reasonable price, and having superior deodorizing action and antimicrobial and mildew proofing action. Further, in order to achieve the first object, a first antimicrobial treatment method in accordance with the present invention is adapted to treat a target object using an aqueous solution containing the silver-chloro complex salts in the presence of the oxidizing agents.

With this method, it is possible to provide an antimicrobial treatment method having both immediate and residual properties for disinfection and deodorizing, having a wide disinfecting spectrum, capable of preventing resistant bacteria, having good safety, capable of maintaining sufficient stability even in a medium or environment in which sulfides coexist, and having a reasonable price, and having superior deodorizing action and antimicrobial and mildew proofing action. It is the second object of the present invention to provide an antimicrobial agent and an antimicrobial treatment method which can be used conveniently at the concentration of preservation, and which does not result in rusting or deposition of salts, and which has the immediate property as well as cleansing ability.

In order to achieve the second object, a second antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and chloride for supplying chloride ion, and further compounds having compatibility with the solvent which dissolves the chloride. The second antimicrobial agent preferably further includes the solvent which dissolves the chloride. Further, the solvent is preferably water.

With this constitution, the compounds having compatibility with the solvent which dissolves the chloride capture water or other solvents, and accordingly it is possible to reduce the free water or solvent which is not chemically and physically captured in the vicinity of the silverchloro complex salts in the antimicrobial agent solution. As a result, it is possible to increase the apparent concentration of the chloride ion which contribute to stability of the silver-chloro complex salts. Thus, the concentration of the chloride ion actually contained in the antimicrobial agent solution can be reduced while maintaining the apparent concentration of the chloride ion which is directly required to stabilize the silver-chloro complex salts. As a result, the antimicrobial treatment can be effected easily without diluting the antimicrobial agent solution In use.

- 15 The compounds having compatibility with the solvent which dissolves the chloride are preferably alcohol. The alcohol captures water, etc., and satisfies the immediate property, and thus it is possible to reduce the concentration of the chloride ion, and, at the same time, effect the immediate property for the antimicrobial agent. The compounds having compatibility with the solvent which dissolves the chloride may alternatively be surfactants. The surfactants capture water, etc., and satisfies the cleansing ability, and thus it is possible to reduce the concentration of the chloride ion, and, at the same time, obtain the cleansing ability for the antimicrobial agent.

In order to achieve the second object, a second antimicrobial treatment method in accordance with the present invention is adapted to treat the target object with the second antimicrobial agent.

With this method, it is not required to change the preservation concentration of the chloride ion in use, thus effecting the antimicrobial treatment conveniently.

It is the third object of the present invention to provide an antimicrobial agent which can effectively demonstrate the antimicrobial properties without spoiling the appearance or feel of the target object due to

- 16 formation of crystals such as white crystals on the surface of the target object after the antimicrobial treatment and even when the target object is a liquid, or, for example, has a complicated surface structure such as fine voids.

In order to achieve the third object, a third antimicrobial agent in accordance with the present invention includes a chloride which has at least one of (I) the property capable of existing as a supersaturated aqueous solution for 24 hours or longer in the presence of a crystal nucleus at least at room temperature, and (II) the property capable of being decomposed when dissolved in water, and the silver-chloro complex salts.

With this constitution, by the chloride having at least one of the foregoing properties, there will be no crystallization of the deposited chloride even when the antimicrobial agent is dried and the chloride is concentrated, and the chloride stably exists, for example, as the residue of a transparent and irregular form in the super saturated state. Thus, the appearance or feel of the target object will not be spoiled by the white crystals, etc., of the chloride on the surface of the target object.

The chloride is preferably polyaluminium chloride.

Polyaluminium chloride has the property of forming

- 17 -

colloid hydroxides in an aqueous solution. The colloid hydroxides absorb silver chloride and disperse it in the aqueous solution, and thus fine particles of the silver chloride which demonstrates the antimicrobial properties can be localized in the aqueous solution. As a result, by using the polyaluminium chloride as the chloride, it is possible to provide, when the target object is, for example, a liquid such as foul water or waste fluid, an antimicrobial agent having improved antimicrobial properties than the conventional antimicrobial agents which contain ammonium chloride, or chlorides of alkali metal or alkali earth metal.

The chloride may alternatively be organic compounds.

This allows the surface tension of the antimicrobial agent solution to be reduced compared with the conventional antimicrobial agents which contain ammonium chloride, or chlorides of alkali metal or alkali earth metal, thereby increasing the permeability of the antimicrobial agent solution with respect to the target object. As a result, it is possible to provide an antimicrobial agent which can effectively demonstrate the antimicrobial properties for target objects having a complicated surface structure such as fine voids.

The organic compounds are preferably cationic surfactants, and benzalkonium chloride is particularly

18 - preferable. This allows the surface tension of the antimicrobial agent solution to be further reduced, thus further increasing the permeability of the antimicrobial agent solution with respect to the target object. As a result, it is possible to provide an antimicrobial agent which can demonstrate the antimicrobial properties further effectively with respect to target objects having a complicated surface structure such as fine voids.

Further, since benzalkonium chloride has the antimicrobial properties of superior immediate action, i.e., superior disinfecting ability, it is possible to provide an antimicrobial agent with the immediate property. It is the fourth object of the present invention to provide an antimicrobial agent and a producing method thereof having wide use, for example, such as mixing with a powder such as a powder detergent, or kneading with resin or fiber in the form of fine particles.

The inventors of the present invention have found, in the course of its completion, a solid antimicrobial agent and a producing method thereof which can stably demonstrate antimicrobial properties.

In order to achieve the fourth object, a fourth antimicrobial agent in accordance with the present invention includes silver-chloro complex salts and

- 19 chloride for supplying the chloride ion, and is a solid.

With this constitution, since the antimicrobial agent is a solid, it is possible to provide an antimicrobial agent having wide use, for example, such as mixing with a powder such as a powder detergent, or kneading with resin or fiber, etc., in the form of fine particles. Further, by the silver-chloro complex salts having the sustained antimicrobial property and by the chloride which stabilizes the silver-chloro complex salts, it is possible to provide an antimicrobial agent having stable antimicrobial properties.

In order to achieve the fourth object, a producing method of the fourth antimicrobial agent in accordance with the present invention includes the steps of preparing a mixture by mixing silver and/or silver compound, and the chloride for supplying chloride ion, and water, and removing water from the mixture.

With this constitution, since the mixture contain the chloride, the silver-chloro complex salts exist stably even when water is removed from the mixture. As a result, the solid antimicrobial agent having stable antimicrobial properties can be produced. Thus, it is possible to provide a producing method of the antimicrobial agent having wide use, for example, such as mixing with a powder such as a powder detergent, or

- 20 kneading with resin or fiber, etc., in the form of fine particles. Further, by the sustained antimicrobial property of the silver-chloro complex salts formed in the mixture, and by the chloride which stabilizes the silver-

chloro complex salts, it is possible to provide a producing method of the antimicrobial agent having stable antimicrobial properties.

It is the fifth object of the present invention to provide a detergent and laundry supplement which can conveniently effect the antimicrobial treatment with the sustained property without resulting in change in color of the target object, and to provide an antimicrobial treatment method which can conveniently effect the antimicrobial treatment with the sustained property without resulting in change in color of the target object. After extensive research to achieve this object, the inventors of the present invention have found in the course of its completion that the foregoing object can be achieved by adding the silver-chloro complex salts in the a cleansing solution liquid (solution) when washing, for example, fiber products, etc. That is, in order to achieve the fifth object, the detergent in accordance with the present invention includes the silver-chloro complex salts.

- 21 With this constitution, by the antimicrobial ability of the silverchloro complex salts, the antimicrobial treatment can be effected on a washing target object (target object) without resulting in change in color of the washing target object. Further, since the silver-

chloro complex salts which are diluted in the cleansing solution form fine particles of the silver chloride and are absorbed on the surface of the washing target object, the sustained antimicrobial property can easily be effected in laundry.

Further, with this constitution, since the silver-

chloro complex salts are stable with respect to acid or heat, and do not react with ingredients of the detergent, for example, such as the anionic surfactant, and thus can stably sustain the antimicrobial ability, it is possible to perform washing and antimicrobial treatment at the same time. Further, by the antimicrobial ability of the silver-chloro complex salts, antiseptic effect can be obtained for the detergent.

Note that, the detergent preferably has the washing action by including a surfactant.

In order to achieve the fifth object, the laundry supplement in accordance with the present invention includes the silver-chloro complex salts.

With this constitution, when the silver-chloro

- 22 complex salts include, for example, softening agents, it is possible to effect a softening property, and at the same time, the antimicrobial treatments on the washing target object ttarget object) by the antimicrobial ability of the silver-chloro complex salts without resulting in change in color of the washing target object. Further, since the silver-chloro complex salts which are diluted in the cleansing solution form fine particles of the silver chloride and are absorbed on the surface of the washing target object, it is possible to obtain the sustained antimicrobial property conveniently when effecting the softening property, etc. Further, with the foregoing constitution, since the silver-chloro complex salts are stable with respect to acid or heat, and do not react with ingredients of the laundry supplement, for example, such as the anionic surfactant, and thus can stably sustain the antimicrobial ability, it is possible to effect the softening property, etc., and the antimicrobial treatment at the same time. Further, by the antimicrobial ability of the silver-chloro complex salts, antiseptic effect can be obtained for the laundry supplement. The laundry supplement preferably further includes a bleaching agent. By the oxidizing effect of the bleaching agent included in the laundry supplement, the

- 23 -

silver-chloro complex salts do not lose its antimicrobial ability. Thus, with this constitution, it is possible to provide a laundry supplement which employs both bleaching agent and antimicrobial agent. Note that, the bleaching agent is preferably hypochlorite and/or chlorite.

In order to achieve the fifth object, a third antimicrobial treatment method in accordance with the present invention is adapted to treat the target object in a solution which contains the silver-chloro complex salts. With this constitution, by the antimicrobial ability of the silverchloro complex salts, it is possible to conveniently effect the antimicrobial treatment without resulting in change in color of the target object. Further, since the silver-chloro complex salts which are diluted in the

treatment liquid form fine particles of the silver chloride and are absorbed on the surface of the target object, the antimicrobial effect on the target object can easily be sustained.

The solution is preferably a cleansing solution containing the surfactant. By using such a cleansing solution, the target object can be subjected to the antimicrobial treatment as well as washed.

Further, the third antimicrobial treatment method has the prominent effect of preventing change in color of

- 24 fiber products when the target object is fiber products.

It is the sixth object of the present invention to provide disposable sheets which can be removed while a person is lying thereon, and a disposable sheet set which allows a single care giver to replace the disposable sheets when it is used for beds of permanently-ill patients. In order to achieve the sixth object, the disposable sheets in accordance with the present invention include notches with respect to and in the longitudinal direction of rectangular sheets so that the sheets can be separated into two, and a tape for sealing the notches, which is stuck on the sheets by a pressure sensitive adhesive agent covering the notches.

With this arrangement, the sheets can be removed only by moving the sheets while a person lying thereon.

That is, for example, a person lying on the disposable sheets is moved to the right side of the sheets, and then after peeling off the tape, by pulling the left side of the sheets with hands, the sheets are separated at the notches, removing the left side of the sheets. Then, the person lying on the sheets is moved to a portion from which the left side of the sheets was removed, and the right side of the sheets is pulled to remove the right side of the sheets.

À 25 Thus, with the foregoing arrangement, by placing another sheets in advance under the disposable sheets, the sheets can be replaced while the person is lying thereon, and therefore, when used for beds of permanentlyill patients (simply "patients" hereinafter), it is not required to move the patient from the bed and the sheets can be removed by a single care giver.

Further, with the foregoing arrangement, since the notches are sealed by the tape, it is possible to prevent urine or sweat, etc., of the person (e.g., patient) lying thereon from seeping out into the underlying sheets, for example, another disposable sheets, through the notches in use.

Note that, as the phrase is used herein, "notches which allow the sheets to be separated from each other" is meant to indicate those notches which allow the sheets to be separated into two along the notches by being pulled with hands. Also, "notches" not only indicate slits, i.e., a long narrow opening, but a sewing pattern, i.e., perforations in the form of a dotted line.

In order to achieve the sixth object, the disposable sheets in accordance with the present invention include two rectangular sheet elements which are disposed side by side with their longer sides adjoining each other, and a tape which is attached on the sheet elements by a

- 26 pressure sensitive adhesive agent so as to cover a portion of the sheet elements in contact with each other.

With this arrangement, the sheet elements can be removed only by moving the sheet elements while a person lying thereon. That is, for example, a person lying over the two sheet elements is moved to the right side of the sheet elements and the tape is peeled off, thus allowing the left side of the sheet elements to be removed by pulling it with hands. Then, the person lying on the disposable sheets is moved to a portion from which the left side of the sheet elements was removed, thus allowing the right side of the sheet elements to be removed by pulling it with hands.

Thus, with the foregoing arrangement, by placing another sheets in advance under the disposable sheets, the sheets can be replaced while the person is lying thereon, and therefore, when used for beds of permanently- ill patients, it is not required to move the patient from the bed and the sheets can be removed by a single care giver.

Further, with the foregoing arrangement, since the portion where the sheet elements are in contact with each other is sealed by the tape, urine or sweat, etc., of the person (e.g., patient) lying thereon can be prevented from seeping out into the underlying sheets, for example,

another disposable sheets, through the gap between the sheet elements.

The disposable sheets having the foregoing arrangement preferably further include the antimicrobial and deodorizing agent and a polymer water absorbent. As a result, the antimicrobial and deodorizing effect can be obtained by the antimicrobial and deodorizing agent.

Further, by the polymer water absorbent, it is ensured that the urine or sweat, etc., can be absorbed, thus surely preventing urine or sweat, etc., from seeping out through the disposable sheets. As a result, clean environment can be maintained.

Note that, as the term is used herein, "antimicrobial and deodorizing agent" refers to those additives which have both antimicrobial action and deodorizing action.

The disposable sheets of the foregoing arrangements preferably include the solid silver-chloro complex salts.

As a result, it is possible to obtain the antimicrobial and deodorizing action with a superior sustained (residual) property for the disposable sheets.

In order to achieve the sixth object, the disposable sheet set in accordance with the present invention has the disposable sheets of the foregoing arrangements, any of which are stacked one over another.

With this arrangement, once placed on the bed of a permanently-ill patient, the disposable sheets can be replaced only by moving the sheets while the patient lying thereon. Thus, it is not required to move the patient from the bed and the disposable sheets can be replaced only by a single care giver.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a graph which shows a relationship between incubation time and proliferation of bacteria (indicated by absorbance) in a growth test of Escherichia cold in a medium containing sulfides of Example 3.

Figs. 2(a) and 2(b) are drawings which show one embodiment of disposable sheets of the present invention, in which Fig. 2(a) is a perspective view, and Fig. 2(b) is a side view.

Fig. 3 is a perspective view of the disposable sheets of Figs. 2(a) and 2(b), showing a state in which a tape is peeled off.

Fig. 4 is a cross sectional view showing one example of sheets used as the disposable sheets of Figs. 2(a) and 2(b). Fig. 5 is a cross sectional view showing another example of sheets used as the disposable sheets of Figs. 2(a) and 2(b).

- 29 Fig. 6 is a perspective view showing one embodiment of a disposable sheet set of the present invention.

Figs. 7(a) and 7(b) are drawings which show another embodiment of disposable sheets of the present invention, in which Fig. 7(a) is a perspective view, and Fig. 7(b) ., IS a side view.

Fig. 8 is a perspective view of the disposable sheets of Figs. 7(a) and 7(b), showing a state in which a tape is peeled off.

Fig. 9 is a perspective view showing another embodiment of the disposable sheet set of the present invention. PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

The following will describe in detail a first antimicrobial agent, a producing method of the first antimicrobial agent, and a first antimicrobial treatment method. The first antimicrobial agent in accordance with the present invention includes a silver-chloro complex salts and oxidizing agents.

Note that, in the present invention, "silver-chloro complex salts" indicates salts with a complex ion structure as represented by the following structural formula (1).

- 30 C1 C1 - Ag - C1 (1) C1 The antimicrobial agent may be an aqueous solution containing the silver-chloro complex salts and oxidizing agents (referred to as "antibacterial agent aqueous solution" hereinafter where distinction is necessary), or may be a mixture containing solid chlorocomplex salt and solid oxidizing agents. Note that, even though the following explanation is based mainly on the antimicrobial agent in the form of an aqueous solution, the same effect can be expected with the mixture of the solid chlorocomplex salt and the solid oxidizing agents.

In the antimicrobial agent, the silver ion is stabilized in the form of a chlorocomplex salt (silver-

chloro complex salt) so that it can coexist with the oxidizing agents. That is, the antimicrobial agent is adapted to stabilize the silver ion in the form of the chlorocomplex salt so that the silver ion can coexist with the oxidizing agents in the aqueous solution without precipitation of the silver ion.

The silver-chloro complex salts are stabilized with chloride ion of high concentration. Thus, the

- 31 antimicrobial agent preferably includes a chloride for supplying chloride ion, in addition to the silver-chloro complex salts and oxidizing agents. Accordingly, the antimicrobial agent aqueous solution preferably includes silver ion as the chlorocomplex salt and the oxidizing agents in a chloride aqueous solution.

The Chloride for supplying the chloride ion is not particularly limited and includes: chlorides (chlorides of alkali metals) having counter ions of alkali metal ions such as lithium ion, sodium ion, and potassium ion; chlorides having counter ions of alkali earth metal ions such as magnesium ion and calcium ion; aliphatic quaternary ammonium salts, such as aliphatic guaternary ammonium chloride having one or two alkyl groups of a long chain with 12 to 18 carbon atoms, tetramethylammonium chloride, and tetraethylammonium chloride; polyamine hydrochlorides, such as ethylenediamine hydrochloride, hexamethylenediamine hydrochloride, and hexamethylenetriamine hydrochloride; primary amine hydrochlorides, such as methylamine hydrochloride and ethylamine hydrochloride; secondary amine hydrochlorides, such as dimethylamine hydrochloride and diethylamine hydrochloride; tertiary amine hydrochlorides, such as trimethylamine hydrochloride and triethylamine hydrochloride; aromatic amine

- 32 -

hydrochlorides, such as pyridine hydrochloride and aniline hydrochloride; aromatic quaternary ammonium salts, such as triethyl benzyl ammonium chloride, benzalkonium chloride, benzethonium chloride, pyridinium chloride, and imidazolinium chloride.

In the case where an alkaline oxidizing agents such as sodium hypochlorite are used to coexist as the oxidizing agents, it is particularly preferable that the chloride for supplying chloride ion is a chloride which does not precipitate by generating hydroxides even in the alkaline aqueous solution, i.e., more specifically, chlorides of alkali metals, such as sodium hydroxide and potassium hydroxide.

Unlike thiocyanate complex salt, thiosulfate complex salt, and silver salts of amino acids, the silver-chloro complex salts do not precipitate into silver hydroxide by being oxidized and decomposed by the alkaline oxidizing agents such as sodium hypochlorite. Further, in the case where the chloride for supplying chloride ion is contained, because the silverchloro complex salts are stabilized by the chloride ion, the silverchloro complex salts do not precipitate by producing silver chloride with the coexisting chloride ion even when the chlorine-

containing oxidizing agents is used.

Further, it is well known that silver ion converts

33 - itself to silver sulfide and loses its antimicrobial activity in the presence of sulfur or sulfides. However, with the first antimicrobial agent in accordance with the present invention in which the oxidizing agents coexist with the silver ion, sulfur or sulfides can be oxidized even when it is present, thus preventing forming silver sulfide. Therefore, the first antimicrobial agent in accordance with the present invention can be used for antimicrobial treatment in places where sulfur or sulfides are present, which was not possible with the conventional silver antimicrobial agents.

The oxidizing agents used in the first antimicrobial agent in accordance with the present invention are not particularly limited but chlorite and/or hypochlorite are suitable since they are inexpensive, colorless, sufficiently stable as the aqueous solution for several months, and superior particularly in their immediate properties. Further superior immediate property can be expected with the hypochlorite. On the other hand, the chlorite has the pH in the neutral range and thus has a characteristic which allows a wide selection of metal ions which can be mixed, and a characteristic which is more stable with respect to decomposition than the hypochlorite. Further, the chlorite is preferably sodium chlorite in particular, and the hypochlorite is

- 34 preferably sodium hypochlorite in particular.

Note that, even though many oxidizing agents have the property wherein the content is reduced by self-

decomposition, since the silver-chloro complex salts do not promote decomposition of the oxidizing agents, the stability of the oxidizing agents can be maintained with the silver-chloro complex salts.

The antimicrobial action of the first antimicrobial agent in accordance with the present invention is sufficiently demonstrated by including the silver ion in not less than 0.05 mg/1 in the chloride aqueous solution.

Thus, the concentration of the silver-chloro complex salts in the aqueous solution is preferably not less than 0.05 mg/ in silver ion equivalent concentration.

However, in the case where there exists an organic substance including sulfur in the form of sulfides, since a slight amount of silver is consumed as silver sulfide even in the presence of the oxidizing agents, it is further preferable to include the silver ion as the chlorocomplex salt in the amount of not less than 2.5 mg/l. That is, the antimicrobial action is relatively poor when the concentration of the silver ion is less than 2.5 mg/1, and it is preferable for use in antimicrobial treatment of a target object (object to be treated) which does not contain sulfur in the form of

- 35 -

sulfides. Thus, it is further preferable that the concentration of the silver-chloro complex salts in the aqueous solution is not less than 2.5 mg/ in silver ion equivalent concentration.

Further, the concentration of the chloride ion in the aqueous solution may be suitably decided depending on the required concentration of the silver ion. For example, while the silver can be dissolved as the chlorocomplex ions when the concentration of the chloride ion is not less than 0.003 mol/1, in order to obtain the effective concentration of the silver ion of 2.5 mg/1 or greater even in the presence of sulfides, the concentration of the chloride ion is preferably not less than 0.02 mol/1. Further, even though the concentration of the oxidizing agents in the aqueous solution may be set at an arbitrary concentration, the oxidizing agents are preferably used at various concentrations, for example, at a higher concentration as required when the target object includes a large amount of sulfur or sulfides. As described, a preferable form of the first antimicrobial agent in accordance with the present invention includes as main components the oxidizing agents, the chlorocomplex salt of silver ion, and the chloride for stabilizing the chlorocomplex salt, and it

- 36 may further include other additives such as a surfactant, fragrance, and pigment.

According to the producing method of the first antimicrobial agent in accordance with the present invention, the chloride aqueous solution, silver and/or silver compound, and oxidizing agents are mixed. Here, the silver indicates a silver metal (silver simple substance). According to a particularly suitable producing method of the first antimicrobial agent, a chloride aqueous solution having a predetermined concentration is mixed with the silver and/or silver compound, and the silver ion in a predetermined concentration (preferably not less than 0.05 mg/) is dissolved as the chlorocomplex salt in the chloride aqueous solution, and a predetermined concentration of the oxidizing agents are dissolved in the chloride aqueous solution including the silver ion as the chlorocomplex salt. As a result, it is possible to obtain the antimicrobial agent in accordance with the present invention, i.e., the antimicrobial agent which includes a predetermined concentration of the silver ion as the chlorocomplex salt in the chloride aqueous solution together with the oxidizing agents.

Further, according to the first antimicrobial treatment method in accordance with the present

- 37 -

invention, an aqueous solution including the silver-

chloro complex salts, or, more preferably, the chloride aqueous solution including the silver-chloro complex salts is used in the presence of the oxidizing agents so as to treat a target object. The oxidizing agents may be mixed beforehand with the aqueous solution including the silver-chloro complex salts, or used together with the aqueous solution including the silver-chloro complex salts when treating the target object. That is, the target object may be treated using the antimicrobial aqueous solution in accordance with the present invention, i.e., the aqueous solution including the silver-chloro complex salts and the oxidizing agents, or, alternatively, the target object may be treated using the aqueous solution including the silver-chloro complex salts, together with the oxidizing agents. Further, the target object may be treated using an aqueous solution which is prepared by dissolving in water a solid antimicrobial agent, which is a mixture containing a solid chlorocomplex salt and solid oxidizing agents (preferably further with a solid chloride) .

The antimicrobial agent aqueous solution in accordance with the present invention may be used in undiluted form (antimicrobial agent aqueous solution as prepared) to treat a target object, or, alternatively,

- 38 -

the antimicrobial agent may be adapted to treat the target object with the undiluted solution and then wash the target object with water, or the target object may be treated after diluting the undiluted solution with water.

When treating the target object with the undiluted solution, the oxidizing agents demonstrate the immediate antimicrobial action, and the silver-chloro complex salts demonstrate the sustained antimicrobial action. In the method in which the target object is treated with the undiluted solution and then washed with water, the concentration of the chloride ion decreases in washing and the silver-chloro complex salts are fixed on the surface of the target object by converting itself to silver chloride which is hardly soluble. The silver chloride formed this way is in the form of ultra fine particles, and is dispersed and has a wide surface area.

Therefore, the silver chloride thus prepared shows long-

term strong antimicrobial activity and does not result in blackening, which is commonly seen when the silver chloride is formed. Thus, this method demonstrates the immediate antimicrobial action by the oxidizing agents, and the residual antimicrobial effect by the fine silver chloride. Further, in the method where the target object is treated after diluting the undiluted solution with water, the chlorocomplex salt of the silver ion is

- 39 -

converted to the silver chloride when diluted, thus having the immediate antimicrobial action by the oxidizing agents and the residual antimicrobial action by the fine silver chloride, as in the case where the target object is water washed after treatment with the undiluted solution. Note that, in the method in which the target object is treated after diluting the undiluted solution with water, it is preferable that the concentration of the silver ion after dilution with water satisfies the foregoing conditions.

Referring to Examples, the following will describe the first antimicrobial agent, producing method of the first antimicrobial agent, and first antimicrobial treatment method in accordance with the present invention. [Example 1]

The present example examined stability of the antimicrobial agent solution.

Firstly, an antimicrobial agent solution (solution C) was prepared as the first antimicrobial agent in accordance with the present invention by mixing, in the volume ratio of 1:1, an aqueous solution (solution A) containing 35 percent by weight of sodium chloride and the silver-chloro complex salts in the silver ion concentration of 500 ppm with an aqueous solution

- 40 (solution B) of sodium hypochlorite containing 137 g/l of effective chlorine. The concentration of the silver-

chloro complex salts in the antimicrobial agent solution was about 3 x 102 mg/l in silver ion equivalent concentration. These solutions A, B. and C were stored for 50 days under the condition of 30 C and change in the amount of effective chlorine and change in solution state were measured for each solution. Table 1 shows the results of observation of the amount of effective chlorine (g/l) and the solution state at the start of the test (immediately after mixing) and after 50 days at 30 C, and also a remaining fraction of the effective chlorine (with respect to the initial amount of chlorine at 100 at the start of the test) after 50 days at 30 C. The results show that decline in effective chlorine was not facilitated even in the presence of the silver-chloro complex salts and preservation did not suffer. Further, it was found that the silver-chloro complex salts did not become unstable and did not precipitate by being mixed with the sodium hypochlorite.

- 41 Table 1

START OF TEST AFTER 50 DAYS AT 30 C

(IMMEDIATELY AFTER MIXING)

SAMPLE AMOUNT OF REMAINING SOLUTION AMOUNT OF REMAINING SOLUTION

SOLUTION CHLORINE FRACTION STATE CHLORINE FRACTION STATE

(g/l) (A (g/l) (A SOLUTION O _ COLORLESS O _ COLORLESS

A TRANSPARENT TRANSPARENT

SOLUTION 137 100 YELLOW 103 75 YELLOW

B TRANSPARENT TRANSPARENT

SOLUTION 67 100 YELLOW 56 84 YELLOW

C TRANSPARENT TRANSPARENT

[Example 2]

The present Example examined antimicrobial effect on Staphylococcus aureus.

First, using the antimicrobial agent solution (solution C) of Example 1, antimicrobial effect on Staphylococcus aureus was evaluated. Further, as a control, the same evaluation was made using the sodium hypochlorite solution (solution B). The testing method is as follows.

A floor plate made of linoleum was cut into pieces of 10 cm x 10 cm, which were then boiled for an hour four times in water including a neutral detergent so as to remove a plasticizer, etc. On these floor plates were independently sprayed the solution B diluted 200 times and the solution C diluted 100 times using a sprayer in the amount of 1 ml per floor plate. Spraying was repeated

42 at predetermined intervals of four patterns: everyday, every other day, every three days, and every six days.

Also, on each floor plate was sprayed an inoculum of Staphylococcus aureus in the concentration of 102 CFU (Colony Formation Unit)/ml on the daily basis in the amount of about 1 m1 per floor plate. For the floor plates treated with the solution C, inoculation was made after the surface of the floor plates was dried after the solution treatment. On the 7th day of the experiment, an YP medium was sprayed on the floor plates, and the floor plates were incubated for 2 days under the conditions of 30OC and 100 R.H. (Relative Humidity).

Table 2 shows the results.

- 43 Table 2

TREATING ELAPSED TIME FROM START OF

SOLUTION EXPERIMENT (TREATMENT) IN DAYS PROLIFERATION

OF BACTERIA

DAY DAY DAY DAY DAY DAY

NONE _ _ _ _ _ _ ++

SOLUTION B o o o o o o SOLUTION B o. _ o _ o _ SOLUTION B o _ _ o _ _ SOLUTION B o _ _ _ _ _ ++ _ SOLUTION C o o o o o o _ SOLUTION C o _ o _ o _ _ SOLUTION C o _ _ = = _ SOLUTION C o _ _ _ _ _ In Table 2, "NONE" under the column of treating solution indicates no treatment. The symbol "o" indicates spraying of the treating solutions, and "-" under the olumn of elapsed time from the start of the experiment treatment) in Table 2 indicates no spraying of the Creating solutions. Also, under the column of proliferation of bacteria in Table 2, the symbol "++" and "+" indicate the number of colonies per floor plate in The order of several hundreds (102 to 103) and several tens 10 to 102), respectively, and "-" indicates no colony.

As can be seen from Table 2, the solution B containing only sodium hypochlorite did not show the residual effect for Staphylococcus aureus, whereas the

- 44 solution C which was diluted to contain the same amount of effective chlorine showed the residual effect for 2 days. [Example 3]

The present example compared a growth rate of bacteria using the antimicrobial agent in accordance with the present invention and a comparative antimicrobial agent which did not include the oxidizing agents.

Firstly, a silver-chloro complex salt solution (solution a) was prepared as the comparative antimicrobial agent by dissolving 35 g of calcium chloride and 0.05 g of silver chloride in lOO ml of water. Also, an antimicrobial agent solution (solution b) was prepared as the first antimicrobial agent in accordance with the present invention by adding 3 parts by volume of a 4.3 percent by weight solution of sodium hypochlorite with respect to 7 parts by volume of the solution a.

Then, the Trypto-Soya Broth "Nissui" (TSB) medium (provided by NISSUI PHARMACEUTICAL Co., Ltd.) was adjusted to have a pH of 7.2 and was sterilized for 15 minutes at 121 C and divided into two equal parts. To each of the two parts was added the solution a or solution b in the amount of 0.1 percent by weight (0.5 mg/1 of solution a and 0.35 mg/l of solution b in Ag ion

- 45 equivalent concentration).

Each TSM medium of the solution a or solution b was inoculated with 20 Al of a 100 times diluted inoculum of pre-incubated Escherichia cold (species: Escherichia cold MC1061), and was incubated for 28 hours at 37 C. During incubation, absorbance with respect to the light of 660 nm was measured for every 60 minutes using a spectrophotometer (provided by Shimadzu Corporation:product name (Shimadzu SP-20A)), and the growth curve as shown in Fig. 1 was obtained. Note that, "CONTROL" indicates the result of measurement using a cultured medium which was incubated as above but without inoculating the strain.

The TSB medium includes proteins which contain sulfur in the form of sulfides, such as peptone and soybean peptone. As can be seen in Fig. 1, while the bacteria start to proliferate after 6 hours in the control, proliferation of bacteria is inhibited for 8 hours with the solution a and for 19 hours with the solution b.

[Example 4]

The present example examined minimum growth inhibiting concentration with respect to various microbes using the solutions a and b of the Example 3.

Firstly, the minimum growth inhibiting concentration

- 46 of the solutions a and b was examined with respect to the Escherichia cold MC1061 used in Example 3.

After adjusting the Nutrient Broth (NB) medium (provided by DIFCO Corporation) to have a pH of 7.2, the medium was sterilized for 15 minutes at 121 C. To the medium was added the solution a or solution b to have the solution concentration of each medium as shown in Table Then, each medium was inoculated with 20 pi of a 100 times diluted inoculum of pre-incubated Escherichia cold (species: Escherichia cold MC1061), and was incubated for 24 hours at 37 C. The absorbance of the cultured media was then measured as in Example 1 to evaluate growth inhibition of the Escherichia cold MC1061 ("E. coli" hereinafter). The absorbance of not less than 0.05 was evaluated as "growth", and absorbance of less than O. OS was evaluated as "no growth". The result of evaluation is shown in Table 3. Note that, in Table 3, "growth" is indicated by "+", and "no growth" is indicated by "-".

- 47 Table 3 SOLUTION SOLUTION a SOLUTION b CONCENTRATION

(VOLUME I)

CONTROL + +

0.08 + +

0.1 + +

O.2 + +

0.3 + +

0.4 + +

0.5 + 0.6 + 0.7 + 0.8 _ _

0.9 1.0 _ As can be seen from Table 3, with respect to E. cold which is the representative of gram-negative bacteria, the solution a showed the antimicrobial effect at the concentration of not less than 0.8 percent by volume (Ag concentration of 4.0 mg/1), whereas the solution b which includes chlorite as the oxidizing agents showed the antimicrobial effect at the concentration of 0.5 percent by volume (Ag concentration of 2.5 mg/1). That is, the minimum growth inhibiting concentration of the solution a was 0.8 percent by volume and that of the solution b was 0.5 percent by volume. The results show that the

- 48 -

solution b which includes the silver ion together with the oxidizing agents have the antimicrobial action at a lower concentration than the solution a even in the medium containing sulfur.

The operations of the foregoing test were performed using Staphylococcus aureus IF03183 ("S. aureus" hereinafter) which is the representative of gram-positive bacteria, instead of E. cold, and the absorbance was measured as above to evaluate growth inhibition of S. aureus by the foregoing evaluation method of Example 3.

The result is shown in Table 4.

Table 4

SOLUTION SOLUTION a SOLUTION b CONCENTRATION

(VOLUME %)

CONTROL + +

0.08 + +

0.1 0.2 + +

0.3 + +

0.4 + +

0.5 + _

0.6 + _

0.7 + _ _

0.8 - _

0.9 + 1.0 _ _

As can be seen from Table 4, with respect to S. aureus which is the representative of gram-positive bacteria, the solution a showed the antimicrobial effect at the concentration of not less than 1.0 percent by volume (Ag concentration of 5.0 mg/l), whereas the solution b showed the antimicrobial effect at the concentration of 0.5 percent by volume (Ag concentration of 2.5 mg/l). That is, the minimum growth inhibiting concentration of the solution a was 1.0 percent by volume and that of the solution b was 0.5 percent by volume. The results show that the solution b has the antimicrobial effect at a lower concentration.

The same test was also performed using other media, and other bacteria, yeast, and filamentous fungus (mold) so as to measure minimum growth inhibiting concentration of the solution b. Specifically, the minimum growth inhibiting concentration ("MIC" hereinafter) of the solution b was measured with respect to E. cold on the desoxycholate medium, S. aureus on the MSA medium, other bacteria on the NB medium, yeast on the SABOURAUD medium, and filamentous fungus on the PDA medium. Note that, the incubation temperature was 25 C and incubation time was 1 day, 3 days, and 7 days for the bacteria, yeast, and filamentous fungus, respectively.

The result showed that the MIC was 0.5 percent per

- 50 volume for the E. cold on the desoxycholate medium and A. aureus on the MSA medium, which was the same as the case the NIB medium was used. With regard to other bacteria, Pseudomonas fluorescent IAM12022, Bacillus subtilis 3013, and Streptococcus lactis 12546 had the MIC of 0.5 percent by volume, 0.3 percent per volume, and 0.4 percent per volume, respectively. With regard to the yeast, Pnichia membranaefaciens IAM49 11 and Debaryomyces hasenJi IAM12209 both had the MIC of 0.3 percent by volume. With regard to the filamentous (mold), Aspergillus oryzae IFO4296 and Penicillium citrinum IFO both had the MIC of 0.5 percent by volume.

Thus, the solution b, which is the first antimicrobial agent in accordance with the present invention, showed the growth inhibiting effect also for the yeast and mold for which growth inhibition is more difficult than for bacteria, at the concentration substantially the same as that for bacteria (Ag concentration of around 1.5 mg/1 to 2.5 mg/l).

[Example 5]

Using the solution b of Example 3, an instant deodorizing test was performed. First, "okara" (bean curd refuse), which is the refuse of wringed soy beans, generated as a by-product in manufacture of "tofu" (bean curd) was spread over two Petri dishes, 100 g on each

- 51 dish. On the rear surface of one of the Petri dishes was uniformly applied approximately 1 g of the solution b, while the other Petri dish was untreated (no solution was added), and the both Petri dishes were allowed to age in the opened state at 20 C.

The result showed that the untreated sample clearly displayed odor in 3 hours and gradually changed its color to brown, whereas the sample applied with the solution b displayed no odor and no coloration was observed.

The following will describe the second antimicrobial agent and the second antimicrobial treatment method using it. The first and other inventors of the present invention have filed an application which relates to an antimicrobial agent including the silver-chloro complex salts (Japanese Unexamined Patent Publication No. 182326/1998 (Tokukaibei 10-182326) (published date: May 7, 1998), prior to the present invention.

Unlike thiocyanate complex salt or thiosulfate complex salt of silver, etc., the silver-chloro complex salts do not contain sulfide ion (S2-). Thus, the silver-

* chloro complex salts do not generate a toxic gas by being decomposed by heat or acid and do not blacken by the silver sulfide produced, and therefore is stable.

Further, since the silver-chloro complex salts are

- 52 highly stable at a high concentration of the chloride ion, it can stably exist in the water-soluble state or near water-soluble state without resulting in precipitation of the silver chloride.

On the other hand, the silver-chloro complex salts have the property of easily depositing the silver chloride or silver metal (silver simple substance) when the concentration of the surrounding chloride ion is reduced by being diluted with water, etc. This is because the amount of the chloride ion which directly contributes to stabilization of the silver-chloro complex salts is reduced in the low concentration state of the chloride ion. The silver-chloro complex salts demonstrate the antimicrobial properties by the silver chloride or silver metal which was deposited in the low concentration state of the chloride ion and is absorbed on the surface of the target object. The antimicrobial agent of the prior application had the antimicrobial effect on the surface of the target object such as various industrial products or home appliances by utilizing the foregoing property of the silver-chloro complex salts.

However, in the antimicrobial agent of the prior application including the silver-chloro complex salts as the main component, due to the property of the silver

- 53 chloro complex salts, it is required to maintain the concentration of the chloride ion at high level during storage, and accordingly it is required to dilute the antimicrobial agent to a predetermined concentration for use. Yet, depending on use of the antimicrobial agent, there are cases where it should be used directly without diluting it with water, etc. Even in such cases, an additional step of diluting the antimicrobial agent to a predetermined concentration is required for use, which complicates the procedure of antimicrobial treatment.

For example, when the antimicrobial treatment is of the form where the antimicrobial agent is stored in a spray container and it is sprayed through a nozzle, etc., for use, the procedure of antimicrobial treatment by diluting the antimicrobial agent in the container every time it is used is extremely tedious and complex.

Also, to store the antimicrobial agent including the silver-chloro complex salts as the main component, as described, the preservation stability needs to be maintained by maintaining the concentration of the silver chloride at high level. Thus, when the antimicrobial agent is to be used without dilution as above, it must be used in the high concentration state of the chloride ion.

Thus, in this case, rust may grow on the surface of the target object, or salts may deposit thereon.

Further, even though the silver-chloro complex salts demonstrate superior antimicrobial activity at a predetermined low concentration, it does not have the immediate property. Thus, in applications where immediate property is required, the silver-chloro complex salts cannot be used by itself. Further, while the silver-

chloro complex salts have the antimicrobial activity, it does not have the cleansing ability, thus preventing the target object to be washed at tine time of the antimicrobial treatment.

In order to solve the foregoing problems, the second antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts, chloride capable of supplying chloride ion by dissociation (electrolytic dissociation) to stabilize the silver-chloro complex salts, and compounds which have compatibility with a solvent which dissolves the chloride ("solvent" hereinafter) such as water, respectively in a predetermined amount.

In the second antimicrobial agent in accordance with the present invention, the compounds having compatibility with the solvent such as water capture the solvent such as water in the antimicrobial agent so as to reduce the solvent which is not chemically and physically captured, such as free water (water which is not chemically and

- 55 -

physically captured) in the vicinity of the silver-chloro complex salts. This makes it possible to reduce the apparent concentration of the chloride ion which exists in the vicinity of the silver-chloro complex salts and which contributes to stabilization of the silver-chloro complex salts. Thus, as a whole, the actual concentration of the chloride ion in the antimicrobial agent can be reduced. The silver-chloro complex salts contained in the second antimicrobial agent in accordance with the present invention are not particularly limited as long as it can supply the complex ion structure as represented by the structural formula (1) in the solution.

The chloride which included in the second antimicrobial agent in accordance with the present invention, and which supplies the chloride ion for stabilizing the silver-chloro complex salts may be, for example, various chlorides as exemplified as the chlorides of the first antimicrobial agent.

Of the chlorides as exemplified above, it is particularly preferable to adopt those which have high solubility for the compounds having compatibility with the solvent. Among such chlorides, organic compounds such as quaternary ammonium salts, polyamine hydrochloride, primary amine hydrochloride, secondary amine

- 56 -

hydrochloride, tertiary amine hydrochloride, and aromatic amines are particularly preferable.

Further, of the chlorides as exemplified above, while chlorides having at least one of lithium ion, magnesium ion, and calcium ion dissolve in compounds having a large polarity such as methanol and ethanol, they are not soluble in compounds with a small polarity among the compounds which are compatible with the solvent. However, since these chlorides have relatively high solubility with respect to the solvent compared with the other chlorides, the concentration of the silver-

chloro complex salts can be maintained at high level, which makes these compounds particularly preferable.

The compounds having compatibility with the solvent, included in the second antimicrobial agent in accordance with the present invention, indicate those compounds which interact with and has affinity toward the solvent molecules such as water molecules, for example, by forming a hydrogen bond or ionic bond with the solvent molecules such as the water molecules.

Further, the second antimicrobial agent in accordance with the present invention may include, as required, a solvent which dissolves the chloride. As such a solvent which dissolves the chloride, other than water or protonic solvent which behaves in the same way as

- 57 water, for example, a non-protonic solvent such as N,N-

dimethylformamide, dimethylsulfoxide; propylene carbonate; and polyvinylpyrrolidone are available. Of these solvents, water is particularly preferable. This is because the solubility of the chloride with respect to water is relatively high compared with other solvents, which allows the concentration of the silver-chloro complex salts to be increased in the antimicrobial agent.

The compounds which have compatibility with the solvent include, for example, among organic compounds, alcohols such as methanol, ethanol, 1propanol, isopropanol, isobutanol, 1-butanol, 2-butanol, 1-

pentanol, 2-pentanol, 3-pentanol, 1,1-dimethyl-1-

propanol, 2,2-dimethyl-1-propanol, 2-methyl-1-butanol, 3-

methyl-1-butanol, 3-methyl-2-butanol, ethylene glycol, diethylene glycol, triethylene glycol, glycerine (glycerol), polyethylene glycol, 3-methyl-1butyn-2-ol, 3,6-dimethyl-4-octyne-3,6-diol, 2,5-dimethyl-3-hexene-

2,5-diol, isoprene glycol, ethyl glycol (ethylene glycol monoethylether), ethyl diglycol (diethylene glycol monoethylether), ethyl triglycol (triethylene glycol monoethylether), butyl glycol (ethylene glycol monobutylether), butyl diglycol (diethylene glycol mononeobutylether), neopentyl glycol (ethylene glycol mononeopentylether), 1,3-butanediol, 1, 4-butanediol, 1,5

- 58 -

pentanediol, 1,6-hexanediol, 1,2,6-hexanetriol, propylene glycol, pentaerythritol, hexylene glycol, polypropylene glycol, 3-methyl-1,5pentanediol, 3-methyl-3-methoxy-1-

butanol, 3-methoxy-1-butanol, catechol, and propylene chlorohydrin; esters such as ethyl acetate, 3-methoxybutyl acetate, propylene glycol monomethylether acetate, ethylene carbonate, methyl lactate, and ethylene glycol diacetate; ethers such as diethyl ether, ethylene glycol dimethylether, diethylene glycol dimethylether, triethylene glycol dimethylether, polyethylene glycol dimethylether, and dioxane; nitriles, such as acetonitrile and succinonitrile; ketones, such as acetone and methylethylketone; amines and their salts, such as N,N-

diethylethanolamine, N,N-dimethylethanolamine, N-(2-

aminoethyl)ethanolamine, N-methyldiethanolamine, isopropylamine, isopropanolamine, ethanolamine, mono-n-

butylamine, n-hexylamine, -m-phenylenediamine, 4-m-

phenylenediamine, hexylamine hydrochloride, benzylamine hydrochloride, diethylamine, biphenylamine, dipropylamine, and triethylamine; organic acids or their salts, such as formic acid, sodium formate, potassium formate, ammonium formate,

- 59 rubidium formate, cesium formate, acetic acid, lithium acetate, sodium acetate, magnesium acetate, calcium acetate, cesium acetate, propionic acid, isobutyric acid, 3-aminobutyric acid, 4-aminobutyric acid, oxalic acid, potassium oxalate, tartaric acid, sodium tartrate, citric acid, (+)-malic acid, glyoxylic acid, malonic acid, sodium maleate, potassium gluconate, sodium gluconate, sodium salicylate, potassium salicylate, ammonium salicylate, sodium phthalate, methanesulfonic acid, 1-

hydroxyethylidene-l, 1-diphosphonic acid, aminotrimethylene phosphoric acid, pentasodium aminotrimethylene phosphonate, sodium 2-methyl-2propene-

1-sulfonate, ammonium 1-naphthalene sulfonate, o-

chlorobenzoic acid, m-chlorobenzoic acid, potassium benzoate, deoxycholic acid, sodium benzenesulfonate, trichloroacetic acid, and sodium nicotinate; sugars or their derivatives, such as D-glucose, sucrose, Lsorbose, maltose, methyl-D-glucoside, and D-

sorbitol; aldehydes, such as glyoxal and acrylaldehyde; phenols, such as o-cresol, m-cresol, p-cresol, o-

chlorophenol, m-chlorophenol, p-chlorophenol, and phenol; and 1,1dichloroethane, 1,2-dichloroethane, dimethylcarbonate, polyethyleneimine, dimethyl sulfoxide,

- 60 dimethylhydrazine, hexanone, phenylhydrazine, N,N-

dimethylformamide, 2,2-dimethoxypropane, polyvinyl pyrrolidone, tetrahydrofuran, ethylenecyanhydrin, acetanilide, urea, codeine phosphate, pyrogallol, betaine, betaine hydrobromide, betaine sulfate, 2,4-

dimethyl pyridine, 2,6-dimethylpyridine, 2,4,6-

trimethylpyridine, 3-methylpyridine, 1-methylpiperidine, 2methylpiperidine, 3-methylpiperidine, and 4-

methylpiperidine. Further, the inorganic compounds having compatibility with the solvent include, for example, silver perchlorate, silver fluoride, aluminium nitrate, aluminium perchlorate, barium nitrate, calcium chlorate, calcium perchlorate, calcium nitrite, calcium nitrate, calcium amidonitrate, Ca[SiF], cadmium selenate, Ce(NH4)2 (NO3) s, Ce (NH4) 2 (NO3) 6, cobalt chlorate, cobalt perchlorate, cobalt nitrate, cobalt sulfate, cobalt thiocyanate, [Co (NH3) 5 (H2O)] (C1O4) 3, [Co (NH3) , (H2O)] (NO3) 3, [Co (NH3) 4 (H2O) 2] (NO3) 3, [Co (NH3) 4 (H2O) 2] 2 (SO4) 3, [Cr (NH3) S (H2O)] (C1O4) 3, [Cr (N) 3 (NH3) s] (C1O4) 2, chrome perchlorate, chrome nitrate, chrome sulfate, cesium sulfate, cesium hydrogencarbonate, Cs2Fe(SO4) 2' cesium molybdate, cesium tungstate, copper chlorate, copper perchlorate, copper sulfate, Cu[SiF]4H2O, Cu(SO3F2)4NH3, copper amidochlorate, iron () perchlorate, iron (II)

- 61 -

perchlorate, iron (I) nitrate, iron (II) nitrate, FeK2(SO4) 2 - 4H2O, FeK2(SO4) 2 - 2H2O, GaNH4(SO4) 2 - 12H2O, cadmium bromate, InNH4(SO4) 232H2O, potassium carbonate, potassium fluoride, dipotassium hydrogenphosphate, potassium molybdate, tripotassium phosphate, K2S2O4, K3H(P2O6)-3H2O, KPH202, K4P2O8-8H2O, KSnBr3.H2O, K2[Sn(OH) 6] 2H2O, K2[Sn(OH) 5], La2Mg3(NO3) 12' lanthanum nitrate, lanthanum bromate, La(NH4)2(NO3)5, lithium bromate, lithium chlorate, lithium perchlorate, lithium iodate, lithium dihydrogenphosphate, lithium nitrate, magnesium chlorate, magnesium perchlorate, magnesium nitrate, Mg3Nd2(NO3) 12, Mg3Pr2 (NO3) 12' magnesium amidosulfate, manganese nitrate, Mn3Nd2 (NO3) 12 24H2O, Mn3Pr2 (NO3) 12 24H2O, hydroxylamine hydrochloride, ammonium fluoride, ammonium dihydrogenphosphate, ammonium nitrate, ammonium sulfate, (NH4)2S2o6, (NH4)2S2Oa, (NH4)2S306, (NH4)2S4O6, ammonium amidosulfate, hydrazinel/2sulfate, (NH4) 2 [Fe(CN) 6], sodium hypochlorite, sodium chlorite, sodium perchlorate, sodium monobydrogenphosphate, sodium nitrate, NaPHO3, sodium amidosulfate, sodium tungstate, Na2S3053H2O, sodium tellurite, Na2[TiF6], neodymium nitrate, neodymium bromate, Nd2Zn3(NO3)l224H2O, nickel chlorate, nickel perchlorate, nickel nitrate, H4P2O6-2H2O, pyrophosphonic acid, Ni3Pr2(NO3) 12' praseodymium nitrate, praseodymium bromate, Pr2Zn3(NO3) 12 24H2O, rubidium nitrate, rubidium

- 62 _luoriae, rubidium hydrogencarbonate, Rb[IBr2], rubidium molybda_e, rubidium tungstate, samarium bromate, samarium titrate, (NH4)2SnBr4.r:2O, strontium nitrate, Te[GeF6], -ioSO4-:2O, yttrium nitrate, ytterbium sulfate, zinc chlorate, zinc perch orate, zinc nitrate, (NH4) 2 [ZrF6], NH)3[Z-F7], and zinc sulfate, etc. The compound having compatibility with the solvent -s pre drably alcohols since they have the immediate antimicrobial action. Among alcohols, ethanol, methanol, and iso-ropanol in particular have superior antimicrobial effect. Thus, by including these compounds as the -ompour. having compatibility with the solvent in the antimicrobial agent, the antimicrobial agent can Demonstrate superior antimicrobial effect.

The compound having compatibility with the solvent may be a mixture of ompounds of two or more kinds as Long as it can be dissolved in the solvent. In this case, -he compounds included as the mixture may be compounds -which come to have compatibility with the solvent by being A. xed.

Su-table combinations of compounds of two or more kinds include: acetic acid and ethyl acetate; acetic acid and hexane; methanol and ethyl acetate; methanol and ohenyl; 1-pronanol and hexanone; acetone and ethyl acetate; acetone and phenol; ethanol and ethyl acetate;

63 - ethanol and diethylether; ethanol and 1,1-dichloroethane; ethanol and 1,2-dichloroethane; and ethanol and hexane, etc. Further, the compound having compatibility with the solvent included in the second antimicrobial agent in accordance with the present invention may be a surfactant as listed below. This allows the antimicrobial agent to also have the cleansing ability at the same time.

However, of those surfactants exemplified below, anionic surfactants are applicable only when their property is such that the anion derived from the anionic surfactant does not form a precipitate, as in the case where the cation existing in the antimicrobial agent is the alkali earth metal ion, etc. For example, the surfactant includes: ether-type non-ionic surfactants, such as polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene sterolether, polyoxyethylene lanolin derivative, polyoxyethylene alkyl phenol ether formaldehydecondensate, polyoxyethylenepolyoxypropylene block polymer, and polyoxyethylenepolyoxypropylene alkyl ether, etc.; ether ester-type nonionic surfactants, such as polyoxyethylene glycerine fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil,

polyoxyethyle-e so-=itan fa_ty acid ester, and polyoxyethyle-e sorb-ol fatty acid ester, etc.; es_er-ty_e nc--ionic surfactants, such as oolyetylenegycol -atty acid ester, fatty acid monogly_eride, polygycerine fatty acid ester, sorbitan atty a_id es_er, pr_?yleneglycol fatty acid ester, and _ar.e s_gar fa- y acic ester; n_ rogen-_ontai "ng ncn-ionic surfactants, such as atty aci a:kaol amide, polyoxyethylene fatty acid amide, olyo'-etylee alkylamine, and alkylamine oxide; nc a--onic surfac_ants, such as alkyl ether ^arboxy' ate, -_y pe-_ide, alky' ether sulfate, secondary higher _lcoho:et:noxy-ulfate, polyo=vethylene alkylphenyl ether -1lfate, ard a:<yl et:ner phos?hate, etc. F_ther, mcng tee ether-tye non-ionic surfactants, polyoxy-thyle-e alky ether inc. udes: polyoxyethylene (3 moles) hexyl etner; polycxyethylene (3 moles) octyl ether; poly-xyethy:ene (3 mo es) decyl ether; polyow--thyle e (= mc:es) octyl -the-; polyoxyethylene (6 oles) Becyl ether; polyoxyethylere (6 moles) dodecyl ether; poly^xyethy_ene (9 moas) octyl ether; polyo=; ethyle-e (3 mc:es) decyl ethe; polyoxyethylene (6 oles) hexadey eher; polyoxyethylene (12 moles) :nexadecl etha-; olyxyethylene (1 moles) nonyl ether;

- 65 polyoxyethylene (20 moles) hexadecyl ether; and polyoxyethylene (23 moles) dodecyl ether, etc. Further, the polyoxyethylene alkylaryl ether includes: polyoxyethylene (9 moles) oxylphenyl ether; polyoxyethylene p-1, 1,3,3-tetramethylbutylphenyl (.5 moles) ether (Triton X-100); polyoxyethylene (20 moles) nonylphenyl ether; and polyoxyethylene dinonylphenyl ether, etc. Note that, the number of moles in the brackets after "polyoxyethylene" indicates the number of additional moles of the ethylene oxide, i.e., the repeated number of ethylene oxide chains.

The evaluation method of the surfactant includes, for example, an emulsion measurement method and peel strength measurement method. The emulsion measurement method is the method in which an oil of an arbitrary type is mixed with water containing a surfactant (surfactant concentration of 1 to 10 (w/v)), and evaluation is made by measuring the amount (volume or height) of the emulsion phase. Note that "(w/v)" indicates the proportion of the solute weight in percent with respect to the total weight of the solution as determined from the total volume of the solution when the specific gravity of the entire solution was 1.

Further, the peel strength measurement method is the method in which a cloth is wetted and soaked in water

66 - including the surfactant, and evaluation is made by measuring the time it takes for the oil to be peeled off from the cloth. To carry out this method more easily, a line is drawn on a glass plate with a "magic ink" (trade name), and the glass plate is soaked in water including the surfactant, and evaluation is made by measuring the t me it Cakes for the magic ink to be removed from the g ass plate. In addition to the foregoing methods, the surfactat may be measured by other methods such as the method o- actually washing dirt off the target object.

The concentration of the chloride in the second antimicrobial agent in accordance with the present invention is not particularly limited, but it is peferab:e that the chloride be added in a predetermined concentration in accordance with the concentration of the s-lver-c:loro complex salts contained in the a-_imicrabial agent. For example, when the chloride is sodium chloride, as shown in Table 5 below, it is p-eferab:e to adopt a predetermined concentration which slows a positive co-relation with respect to the cscentrc_ion of the silver-chloro complex salts.

Specifically, the required concentration of the chloride to stabilize the silve--chloro complex salts (at 25 C) has the allowing correlation in water or in a 70 (w/v) ethanol aqueous solution.

- 67 N r N _ or kD O kD O O O "i N O O O O O

O - O O.q > D a, a) O u, _ _ O O N

05_, -

D, H U m In O m O O at: U LIZ; H

at: O U H at: Z r a\ X 0 )

m Z Zen O O N al at, V O cq

- 68 -urt:ner, the upper limit value of the chloride conce-raio- in determined by (1) the amount of free water e=c., and (2) the solubility of the cation const_=uting the chloride with respect to the solvent.

For example, since the amount of free water which contr:but-s to the dissolution of the chloride is incre_sec as he content of the compound having compG ibilit-. with the solvent deceases, the conce-_ra=ic- c- tie chloride can be increased in the anti._-rcia_ agent as a whole. Further, in the case where the these of cation constituting the chloride has high vdroph-licity, such as lithium, magnesium, calcium, and Organic bases, etc., since the solubility with respe_ to tee solvent is Sleigh, the upper limit value of the chloride is also increased in this case.

the cor_entrat_on of he silver-chloro complex salts contained in he second antimicrobial agent in accordance with::ne present invention becomes Different depending on the:-.pe of the c" ion contained in the antimicrobial agent and to- type of the compound having compatibility with::ne sol-:ent. Mcre specifically, it is determined by (1) --e amo at of solvent which s not chemically and physically Captured, such as free water, (2) the solut:lity f the silve--chloro complex salts with respe to:he sc:vent which is not chemically and

- 69 physically captured, such as free water, and (3) the concentration of chloride ion in the solvent which is not chemically and physically captured.

With regard to (1), the amount of solvent which is not chemically and physically captured, such as free water, which is required for dissolving the silver-chloro complex salts is increased when the content of the compound having compatibility with the solvent is small, thus increasing the upper limit value of the concentration of the silver-chloro complex salts accordingly. Further, with regard to (3), since whether the silverchloro complex salts can stably exist without undergoing dissociation of the complex is determined by how much the chloride ion is dissolved in the solvent which is not chemically and physically captured, such as free water, the upper limit value of the silver-chloro complex salts depends on the concentration of the chloride ion.

For example, in the system of silver-chloro complex salts (sodium tetrachloroargentate (I))-sodium chloride-

water-ethanol, the upper limit value of the silver-chloro complex salts is 46 ppm when water and ethanol was mixed in the volume ratio of 32:68 and 3 %(w/v) of sodium chloride was contained therein.

The concentration of the compound having

- 70 -

compatibiliy with the solvent, included in the second antimicrobial agent in accordance with the present invention, is determined by the amount of the solvent which is no_ chemically and physically captured, such as free water, which are available to dissolve the cation partially constituting the chloride, or silver-chloro complex salts. Thus, the upper limit value of the concentration of the compound having compatibility with the solvent is determined by the relationship between the concentration of thechloride and the concentration of the silver-^hloro complex salts relative to each other.

Note that, he stronger the affinity (hydration when the solvent is water) of the compound having compatibility with the solvent toward the solvent which should be captured by the compound, the lesser the amount of the solvent which is not chemically and physically captured, such as free water.

The proportions of tine silver-chloro complex salts, the chloride, and the compound having compatibility with the solver differ depending on the type of each constituent, as described above.

More specifically, in view of antimicrobial activity, the concentration of the silver-chloro complex salts is preferably not less than 0.01 ppm, and more preferably 3.05 ppm in the silver ion concentration.

The upper limit value of the preferable concentration of the compound having compatibility with the solvent is the solubility of the compound with respect to the solvent. However, to keep the concentration of the chloride concentration low, the concentration of the compound having compatibility with the solvent is increased to the concentration closer to the upper limit value. A specific concentration becomes different depending on the type of the compound. For example, when the compound having compatibility with the solvent is ethanol, 50 to 95 volume is preferable and 60 to 90 volume is further preferable to achieve effective disinfection.

By the antimicrobial treatment method using the second antimicrobial agent in accordance with the present invention (second antimicrobial treatment method), antimicrobial treatment of any kind of target object is possible. Since the second antimicrobial agent in accordance with the present invention in particular has a lower chloride ion concentration and generates less rust compared with the conventionally used antimicrobial agents, it can be suitable used for kitchen equipment or bath tub made of stainless steel (SUS304), which is susceptible to rust. Further, since the antimicrobial agent containing alcohol as the compound having

- 72 Compatibility with the solvent has lipophilic property, -t has he advantage cl uniformly treating equipment made of resin, etc. The second antimicrobial agent in accordance with the present invention may also be used -or var ous objects such as concrete wall, floor, ceramic products, and fiber products, etc. The second an imicrobial treatment method in accordance with the present invention includes, for example, a method of reatment in wh ch the target object s soaked in the second antimicrobial agent, a method of Treatment in which he second antimicrobial agent is sprayed on the target object, a me-hod of treatment in which the second antimicrobial agent is directly applied on the -arget abject, and a method of treatment in which -he target object is wiped with a cloth, etc. , which has absorbed t'ne second Antimicrobial agent.

The following w 11 describe the mechanism by which he si:-/er-ch2oro complex salts con ained in the second antimicrobial agent in accordance with the present -event on demonstrate the antimicrobial properties on the -arget object, and the mechanism by which the chloride and the compound hav ng compatibil ty with the solvent contained in the second antimicrobia agent in accordance with the present invention act on the silver-chloro -omplex salts.

- 73 The silver-chloro complex salts effect the antimicrobial properties on the target object in the form of the silver-chloro complex salts, silver chloride, or silver metal in the solution by the presence of silver as the central ion. The silver ion as the central ion of the silver-chloro complex salts makes the silver chloride to precipitate with decrease in concentration of the surrounding chloride ion. The precipitate of the silver chloride is hardly soluble in water, and thus it is required to prevent precipitation of the silver chloride during storage. However, by further increasing the concentration of the chloride ion in the antimicrobial agent, an equilibrium state can be maintained without resulting in formation of the silver chloride by the chloride ion, thus allowing the silver-chloro complex salts to stably exist in the form of water soluble complex salts.

Therefore, in order to make the silver-chloro complex salts soluble and stabilize it without resulting in precipitation of the silver chloride, the chloride needs to be stored in not less than a certain concentration in the antimicrobial agent. However, when the stored antimicrobial agent is to be used without dilution with the solvent, since the chloride exists in a concentration of not less than a certain level, there

a--- =-a-_acks Ghan ru__ may grow on the target object a-:er the treatten= or salts deposit.

In -he secc-d nt-nicrobial agent in accordance with tee sre_-nt ir^-;en. ion. by mixing the compound having c-pa.ik:lity with the solvent for dissolving the c'-:oride the ccc=ntra_ion of the chloride in the stored aimicr:oial =-ert c be -educed compared with the c-aveti:nal ex_mpe. mere, tine exploration is based on t-- case where the sc:vent dissolving the chloride is -_:er h2-en =he _nt-mic-obial agent enchains the compound h_-, -irg _ompati^-2l-2ty -with tie solvent, the compound c_?tu es cater -n the Equivalent amount of the compound.

2- Is, tee re'_.ive amount of water which is not c2--mi_al:y add:lysica_ly captured, i.e., free water, is -ucd Smearer with:he case where he compound having c:npa=ik:lity w:-h water is not contained.

As _ resul, i- is possible to increase the apparent c:-.cetr__icn c- the _:lloride ion w:^ ch contributes to s:abiliz__icn -, th- silver-chlo_o complex salts.

:-ordir_ly, t2-- con:entrat-on of the chloride ion c:atane- in t2-e ant2icrob-al aged_ can be actually - lucked while a2nta:ning the concentration of the c-:oride for di-ec_ly required for stabilization of the s::ve--c-loro complex salts. This allows easy =--im-cr:oia1 treatment without diluting the

- 75 antimicrobial agent solution in use.

The following will describe the second antimicrobial agent and the second antimicrobial treatment method using it based on Examples.

[Example 6]

The following describes the relationship between the concentration of the chloride when the antimicrobial agent includes the compound having compatibility with the solvent and presence or absence of precipitation of the silver chloride.

An aqueous solution (solution D) including 35 % (w/v) of sodium chloride and 500 ppm of the silver-chloro complex salts in the silver ion concentration was prepared. The solution D was mixed with a solution (30 volume ethanol aqueous solution) to be mixed with the solution D having the composition as shown in Table 6 at the volume ratio of 1:99 so as to prepare an antimicrobial agent solution including the silver-chloro complex salts in the silver concentration as shown in Table 6 and sodium chloride in the final concentration as shown in Table 6. The antimicrobial agent was allowed to age for 4 hours at room temperature and presence or absence of precipitation such as silver chloride was observed. The result is shown in Table 6.

[Examples 7 to 12]

À - 76

The same operatic-s as in Example 6 were performed except If_ the solutions to be mixed with the solution D having tee respective compositions as shown in Table 6.

T:-e resu_ is shown in Table 6.

[Co.-.?arative Examples 1 to 4] The same Aerations as in Example 6 was performed except for the solutions to be mixed with the solution D having t:-e respective compositions as shown in Table 6.

The result is shown in Table 5.

- 77 -

_. _ _. _.

a u a u = 0 0 -' _o 0 0 US U 0 U _ Z a_ In In in u, u' in u, In l U 0 m 0 0 0 0 O to 0 Z Z. ICY

t U n u7 u, u) u, u7 m UO UO U. L Z O _ _ _ _ m U-m 0 O O 0 0 0 0 r) m0 0 O _ O 0 U C,1 o 0 0 r 0 0 _ 0 O 3. O i Z Z 3 l Z Z a la 0 _ _ X

r 0 0 0 t:4 r _ O = Z 3 = = x _ _ __ o

- 78 -- Thor- n able 5, the antimicrobial agents aorta Tins ethanol, glycerine, and acetone in pr-de-=rm-ne ccncer-rations did not show precipitation of the silver h2orie as w-th the antimicrobial agent of Compa-_tive trample 3 containing sodium chloride in the final -oncenation of 6.3 g/l. It can be seen from this resul- that he s-lver-cloro complex salts can be stabi:zed w:-hout _nclud-ng high concentration sodium ch:or_-e but _h f--egoir compounds in predetermined conce--ra_io--. -shc-- by the result of Example 6, the an=im_ roDia_ agent solution containing ethanol in a conce= ratio= o_ about 30 volume percent generated a sleigh- premix tote _f the silver chloride. However, as shown by Ex_mple i, The silver chloride does not orci-:ta=e a a'1 when this antimicrobial agent solution ccta--s sodium chloride in a concentration (final cacheratio 3 35 c!l) lower than conventionally.

xampl_ 13] _. col- and c. aure Is were each incubated on a tr-pt_-oya b Dillon medium (provided by NISSUI PKR'-EUIC'-_ Co.,.td.) for 24 hours at 37 C to prepare an in:-ul-um -av-ng a concentration of about 1Oa CFU/ml.

0.' = of the- -ach noculum thus prepared was indep--de-tl-. acted _o lo Al of the antimicrobial agent

solution having the same composition ratio as in Example 9, i.e., the antimicrobial agent solution of 70 percent by volume of the ethanol aqueous solution containing the silver-chloro complex salts in the silver concentration of 5 ppm and sodium chloride in the concentration of 0.35 g/l, which was then processed for 10 minutes. Then, 0.1 ml of each solution was collected and 10 ml of the triptosoyabouillon solution was added thereto for incubation at 37 C for 72 hours. The turbidity of the incubated solutions was observed by visual inspection and presence or absence of proliferation of the respective bacteria was judged. The results are shown in Table 7.

Note that, in Table 7, "+" indicates proliferation of the bacteria, and "" indicates no proliferation of the bacteria. [Comparative Examples 5 to 9] The same operations as in Example 13 were performed except that the comparative antimicrobial agent solutions as shown in Table 7 were used as the antimicrobial agent solutions. The results are shown in Table 7.

- 80 C ___ of o. _ _ _. a. _ _ Z : D U. Z

U) _ _ ox _ r =' { [-, U i: U

[Example 14]

The antimicrobial agent having the same composition as in Example 9 (antimicrobial agent containing ethanol in a predetermined concentration) was prepared. The antimicrobial agent immediately after the preparation was sprayed on a petri dish of the size 9 cm to have 1 pl/cm2of the antimicrobial agent solution, which was then wind dried and allowed to age at room temperature for 7 days. Then, 0.5 ml of a suspension liquid of E. cold in the concentration of 106 CFU/ml was dropped on the perti dish. The petri dish was then covered with a sterilized film of the size 4.5 x 4.5 cm and was processed for 24 hours at 25 C while maintaining a relative humidity of not less than 90 \. After the process, 0.1 ml of the suspension liquid was collected and spread over a standard agar medium (provided by NISSUI PHARMACEUTICAL Co., Ltd.), which was then incubated for 24 hours at 35 C, and the number of bacteria was counted. The result is shown in Table 8.

[Examples 15 and 16] The same operations as in Example 14 were performed except that an antimicrobial agent solution having the same composition as in Example 10 (antimicrobial agent solution containing glycerine in a predetermined concentration) and an antimicrobial agent having the same

-omposi:ion as Example 11 (antimicrobial agent solution _ontair:ng acetone in a predetermined concentration) were -_sed instead o the antimicrobial agent solution used in example 14. The resul is shown in Table 8.

[C:mparative Examples 10 to 14] Th- same opeaticns as in Example 14 were performed except -hat ccpa-ative antimicrobial agent solutions as --hogan I- Table 8 were used instead of the antimicrobial _get s:2ution used iExample 14. The result is shown in ab- 8.

Table 8

NT3MICR-BIAL AGENT NUTTIER OF BACTERIA

SC_-JTION

! ENCAMP_ 14 SAME AS EXAMPLE 9 O.O

EXAMP-- 15 SAME AS -XAMPLE 10 O O

E.=AMP-- 16 SAME AS EXAMPLE;1 O.O

CCMPAR.':IVE W.'.TER 2.6 x 105 ENCAMP--

CCMPAR':IVE 70 VOLUME ETHANOL 2.1 x 105 E=AMP-- 11 AQUEOUS SOLUTION _

CCMPAR'-:IVE SAME AS -OMPARAT-VE O.O

ENCAMP-- 12 EX't'PLE 1 CCMPAR'-_IVE SAME AS _OMPARAT-VE O.O

E=AMP-- 13 EX;''PLE 2

j CCMPAR':IVE SAME AS:OMPARAT-VE O O I EXEMPT- 14 EK''!PLE 3

[-ample:7] Ar.antim-_roDia: agent solution having the same

- 83 -

composition as in Example 12 (antimicrobial agent solution containing sorbitan monooleate in a predetermined concentration) was prepared. The antimicrobial agent solution immediately after preparation was sprayed on a petri dish of the size 9 cm so as to have 1 p1/cm: of the antimicrobial -agent solution, which was then washed twice with 10 ml of water each time, wind dried, and allowed to age at room temperature for 7 days. On the petri dish was dropped 0.5 ml of the suspension liquid of E. cold in a concentration of 105 CFU/ml, and the petri dish was covered with a sterilized film, which was then processed for 24 hours at 25 C while maintaining the relative humidity of not less than 90 t. After the process, 0.1 ml of the suspension liquid was collected and incubated at 35 C for 24 hours using the standard agar medium and the number of bacteria was counted. The result is shown in Table 9.

[Comparative Examples 15 to 18] The same operations as in Example 17 were performed except that the comparative antimicrobial agent solutions as shown in Table 9 were used instead of the antimicrobial agent solution used in Example 17. The result is shown in Table 9.

- 34 Tabl_ 9 |.-=ICRC_-= A&=- =ER OF BACTERIA

| SOL-.-_ON

-:XALE _ -- ?IE AS _tIP' 12 O. O :OMP}AT_. WA_:R 2. 6 x l Os I:XArQLE _ _OMPRAT_. ?IE LS C-!PARTIN,-- O. O

S:XA1QLE: XA.-- 1

::)MP:iAT_.. -'ME AS C-?AR iTIt'-- O. O i:XALE: CAN-- 2 :QMP:sULT_. ME AS C-!=ARTI\i-: O. O EXALE:- |}{A.?-. 3

[=xa=le 18: 13 -_ of omerc-al_y avai:able edible oil (-oduct =ame "Xissin -alad il" marufactured by The N-_sin Oi- Mills, Ltd) --d 0 -1 of distilled water were ch--ge i- a lOC ml gr--ua=ed cylinder. To this liquid m-:ure w_s adder 5 l c_ an ar. imicrob-al agent solution hc:ng _-e se-e cc=oos ti-n as in Example 12 (a imicr_oial _gert:ontair-ng po yoxyethylene (20 mc_=s) -orbita- mor:_,leate in a predetermined cc=-en- ra:_on). he, t-crac_ated cylinder was sealed or the c_-ning it- a pa-af- :m (trade mark) and was ac:-ated _- s:nak:g t ---ll up nd cow-. The mixture was a'_owe t_ age a 25C _r 13 h-urs and the volume of the em- lsion _:-ase was meas ed Th- result is shown in Table 10.

- 85 [Comparative Examples 19 and 20] The same operations as that in Example 18 were performed except that water and the comparative antimicrobial agent solution having the same composition as in Example 1 were used instead of the antimicrobial agent used in Example 18. The result is shown in Table 10. [Comparative Example 21] The same operations as in Example 18 were performed except that 14 (w/v) of a polyoxyethylene (20 moles) sorbitan monooleate aqueous solution was used instead of the antimicrobial agent solution used in Example 18. The result is shown in Table 10.

Table 10

| ANTIMICROBIAL AGENT VOLUME OF EMULSION

| SOLUTION PHASE

EXAMPLE 18 | SAME AS EXAMPLE 12 9 ml COMPARATIVE | WATER 1 ml EXAMPLE 19 l

COMPARATIVE | SAME AS COMPARATIVE 1 ml EXAMPLE 20 | EXAMPLE 1

COMPARATIVE | (*) 9 ml EXAMPLE 21 l

l (*) 14 (w/v) polyoxyethylene (20 moles) sorbitan monooleat e aqueous solution [Example 19]

1 ml of a commercially available edible oil (product name "Nissin Salad Oil" manufactured by Nissin Oil Mills,

À 86 Let) --as dripped o- a petri dish made of polystyrene having the sze c cm, and spread over the surface of the petri dish with a steering stick made of glass. Then, after Washing the surface of the pe_ri dish with a sponge containing the ant microbial agent solution having the same -omps-_io as in Example 12, the perti dill was rinse_ with ^-stilled water. Then, any residue of the oil was c-se=vec by visual inspection on the surface of the petri fish. The result is shown in Table 11.

omoar_.ie Examples 22 and 23] One cam- opera-ions as in Example 19 were performed excep- that water ^r the antimicrobial agent solution having the same com?ositicn as in Comparative Example 1 immediately _fter -:s preparation were used instead of the a-_imcr-oial a ant so ution used in Example 19. The resul- is shown in Cable 1.

omar__ive Example 24] He sag- operations as in Example 19 were performed exceF- that:4 (rev) of a polycxyethylene (20 moles) sorbian mor_oleate aqueous solution was used instead of the =_imicr bial agent solution used in Example 19. The resul- is st wn in Table 1:.

- 87 Table 11

ANTIMICROBIAL AGENT OIL RESIDUE

SOLUTION

EXAMPLE 19 SAME AS EXAMPLE 12 ABSENT

COMPARATIVE WATER PRESENT

EXAMPLE 22

COMPARATIVE SAME AS COMPARATIVE PRESENT

EXAMPLE 23 EXAMPLE 1

COMPARATIVE (*) ABSENT

EXAMPLE 24

(*) 14 (w/v) polyoxyethylene (20 moles) sorbitan monooleate aqueous solution As shown in Table 11, oil residue was not observed when the antimicrobial agent solution containing polyoxyethylene (20 moles) sorbitan monooleate was used, showing the cleansing ability for the oil. It can also be seen from the results of Example 19 and Example 17 shown in Table 9 that the antimicrobial agent solutions containing the surfactant has the sustained antimicrobial properties and the cleansing ability.

Further, as indicated by the foregoing results altogether, the antimicrobial agent solution containing a predetermined concentration of ethanol can stabilize the silver-chloro complex salts and has the immediate antimicrobial property, i.e., disinfecting ability, without containing sodium chloride in high concentration.

Further, the antimicrobial agent solutions containing ethanol, glycerine, and acetone respectively in

- 38 predet_-minec coven rat-ore can stabilize the silver-

_hloro Complex salts and has the sustained antimicrobial proer-y without cctaining sodium chloride in high -oncen:atior. Further, the antimicrobial agent solution _onai-ing pc:voxyethylene (20 moles) sorbitan monooleate -an stabilize The sil-'er-ch oro complex salts and has the surfac:ant pr_?ety and sustained antimicrobial property -it:nou conta_nirg sodium chloride in high concentration.

I-e ol:_wig well describe a third antimicrobial agent in acac-darce w-th the present invention in detail.

A- described, the silver-ckloro complex salts demons:-ate::^e ant microb al properties by depositing silver color e or silver metal in a low concentration state _ó the chloride ion and by absorption of the silver h'-ori-e or -_lvr.etal on the surface of the target object. Mare spe-if rally, the antimicrobial properties by :he silver chloride absorbed on the surface of the target object are c^_ained by the silver--hloro complex salts -ah ch Become unstable and depos t in the form of pa-tic:es of:he silver chloride in a low concentration state f the chloride ion. For example, the surface of Target ob,ec_s such as fiber products has high surface energy and ac ording:y a large numbe- of deposited silver chlorite par:cles a-e ascrbed on the surface thereof.

- 89 Note that, crystals may grow from the crystal of the absorbed silver chloride acting as a nucleus, and the crystal in this case will have the size of about 1 am.

Thus, in the antimicrobial treatment of target objects, by setting a chloride ion concentration which would generate silver chloride particles, the particles of the silver chloride are fixed or anchored on the surface of the target objects, thereby effecting the antimicrobial treatment on the target objects.

The antimicrobial agent of the prior application (Tokukaihei 10-182326) effects the antimicrobial properties on the surface of the target object such as various industrial products and home appliances by utilizing the foregoing properties of the silver-chloro complex salts.

However, in the antimicrobial agent of this prior application, the chloride contained to supply the chloride ion is limited to ammonium chloride, and chlorides of alkali metal or alkali earth metal. These chlorides all have the property of depositing crystals of, for example, while crystals when they cannot be further dissolved in the solution as the solvent evaporates. Thus, in the case of the antimicrobial treatment where the antimicrobial agent is sprayed or applied on the target object in a concentration which

- 9o demonstrates the antimicrobial properties, the appearance or feel of the target object may be lost by the white crystals, etc. Further, in the antimicrobial agent of the foregoing prior application, when the target object is, for example, a liquid such as foul water or waste fluid, it becomes relatively difficult for the fine particles of the silver chloride to demonstrate the superior antimicrobial properties. This is because when the target object is a liquid such as foul water or waste fluid, unlike the case of fiber products, etc., the fine particles of the silver chloride are homogeneously dispersed in the liquid and delocalized, thus making it relatively difficult to effect the antimicrobial treatment. Further, the antimicrobial agent of the foregoing prior application has large boundary tension (surface tension) and does not permeate sufficiently with respect to the target object. Thus, for example, when the surface of the target object has fine voids, etc., the antimicrobial agent cannot reach into the voids, and bacteria or mold existing in such fine voids may not be subjected to the antimicrobial treatment sufficiently.

Thus, with the foregoing antimicrobial agent, the antimicrobial treatment may not be effected effectively

- 91 on target objects having a complex surface structure, for example, such as the voids.

In order to solve the foregoing problems, the third antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and the chloride for supplying chloride ion to stabilize the silver-chloro complex salts, wherein the chloride has at least one of (I) a property capable of existing as a supersaturated aqueous solution for 24 hours or longer in the presence of a crystal nucleus at least at room temperature, and (II) a property capable of being decomposed when dissolved in water, and the silver-chloro complex salts.

The silver-chloro complex salts included in the third antimicrobial agent in accordance with the present invention are not particularly limited as long as it is a salt having the complex ion structure as represented by the structural formula (1).

The chloride included in the third antimicrobial agent in accordance with the present invention has at least one of (I) the property capable of existing as a supersaturated aqueous solution for 24 hours or longer in the presence of a crystal nucleus at least at room temperature (first property), and (II) the property capable of being decomposed when dissolved in water

- 92 (second property), and it has the function of stabilizing the silverchloro complex salts.

The following will describe in further detail the relationship between the first and second properties and how the third antimicrobial agent in accordance with the present invention prevents appearance or feel of the target object from being affected by deposition of crystals such as white crystals on the surface of the target object.

In general, compounds take the semi-stable state in the supersaturated state, i.e., in a state of a solution (supersaturated solution) containing a solute in the amount equal to or larger than the amount equivalent to the solubility which is distinct to the compounds, and thus they lose stability by external stimuli, for example, such as the presence of the crystal nucleus, and start transition from the liquid phase to the solid phase, i.e., crystal deposition proceeds.

However, by the first properly, the chloride proceeds with the transition at a significantly slow rate or chemical kinetics. Further, the transition proceeds even slower when the crystal nucleus is not present than t'ne case it is present. Thus, under normal antimicrobial treatment conditions, the supersaturated aqueous solution can stably exist practically permanently.

- 93 As described, since the chloride having the first property does not have a clear boundary defining the supersaturation, it does not deposit as a crystal even when the chloride is concentrated by being dried after the antimicrobial treatment. Therefore, with the antimicrobial agent including the chloride having the first property, there will be no crystal deposition which can be observed by visual inspection even when the antimicrobial agent is dried after the antimicrobial treatment. Further, the chloride having the second property is decomposed by being dissolved in water. Here, when referring to "a compound is decomposed by being dissolved in water", it is meant that the compound becomes another compound by being dissolved in water. More specifically, decompose" refers to the phenomenon in which the compound before being dissolved in water is different from the compound which was once dissolved in water and later recovered by removing water.

Thus, in the antimicrobial agent including the chloride having the second property, even in the case where the ingredients of the antimicrobial agent are concentrated by being dried after the antimicrobial treatment, there will be no crystal deposition because the compounds generated from these ingredients by the

- 94 decomposition of the chloride are hydrolyzed products, and mostly basic salts and their polymers.

Thus, by using the chloride having at least one of the first and second properties, it is possible to prevent deposition of crystals such as white crystals, which cause the surface of the target object to have a rough feel or spoil the appearance thereof.

Here, the first and second properties of the chloride in accordance with the present invention can be seen as a unique property whereby there is no match in solubility at a predetermined temperature and accordingly the solubility cannot be c' early determined.

More specifically, the first and second properties refer to the case which satisfies at least one of the following conditions (1) to (3): (I) the solubility which was measured by dissolving the chloride in the solvent does not match the solubility which was measured as the amount of the solvent in the dissolution by concentrating the solution; (2) the solubility which was measured by dissolving the chloride at a fast rate does not match the solubility which was measured by dissolving the chloride at a slower rate; and (3) the solubility which was measured by dissolving the chloride at a predetermined temperature does not match the solubility which was measured by dissolving the chloride at a higher

- 95 -

temperature and then cooling it to the predetermined temperature. Here, whether there is a match is decided by whether the difference exceeds 10 A. The degree of supersaturation of the supersaturated solution in the first property, i.e., the range of measure which indicates the degree of saturation is suitably decided by the type and amount of the chloride used and is not particularly limited.

The chloride included in the third antimicrobial agent in accordance with the present invention has at least one of the first and second properties at least at room temperature, i.e., at a temperature of the everyday environment in which the antimicrobial treatment is usually effected, for example, at a temperature in a range of about 18 C to 25 C.

The chloride included in the third antimicrobial agent in accordance with the present invention includes, for example, organic compounds such as polyaluminium chloride, tetramethylammonium chloride, triocLylmethylammonium chloride, choline chloride, benzalkonium chloride,benzethonium chloride, trimethylbenzylammonium chloride, tributylethylammonium chloride, tributylbenzylammonium chloride, imidazolinium chloride, and N-laurylpyridinium chloride.

Of the chlorides as exemplified above, polyaluminium

- 96 -

chloride is particularly preferable when the target object is a liquid, for example, such as foul water or waste fluid since the polyaluminium chloride forms colloid hydroxides (aluminium hydroxide) in the aqueous solution, which absorbs and disperses the fine particles of the silver chloride which demonstrates the antimicrobial properties, thereby localizing the fine particles of the silver chloride in the aqueous solution.

Further, of the chlorides as exemplified above, the organic compounds, i. e., compounds having carbons can reduce the surface tension of the solution, and increase the permeability of the antimicrobial agent solution with respect to the target object when the antimicrobial agent is used in the form of a solution. As a result, even when the target object has, for example, a complicated surface structure such as small voids, the antimicrobial agent can reach into the voids and sufficiently effect the antimicrobial treatment for the bacteria or mold existing in such small voids, thus making these organic compounds particularly preferable.

Further, among the organic compounds as exemplified as above, the chlorides which function as the cationic surfactant, such as benzalkonium chloride, benzethonium chloride, imidazolinum chloride, and Nlaurylpyridinium chloride, and, in particular, benzalkonium chloride can

- 97 -

further reduce the surface tension of the antimicrobial agent solution, making these compounds even more preferable since they can demonstrate the antimicrobial properties further effectively when used for the antimicrobial treatment on target objects having a complicated surface structure. Further, benzalkonium chloride has the disinfecting ability and thus particularly preferable when antimicrobial properties with superior immediate action are needed.

In the case of the antimicrobial treatment using the third antimicrobial agent in accordance with the present invention, the concentration of the silver-chloro complex salts in the antimicrobial treatment is not particularly limited as long as the antimicrobial properties are sufficiently effected when the antimicrobial agent is used either directly, for example, in undiluted form or the dilution of several tens to several thousand times.

Specifically, the range by which the antimicrobial properties are demonstrated is preferably in a range of 0.01 to 5000 mg/1 in the silver concentration in the solution, or more preferably in a range of 0.1 to 2000 mail, and most preferably in a range of 1 to 500 mg/1 in the antimicrobial treatment.

Further, in the case where the antimicrobial agent in accordance with the present invention is in the form

- 98 -

of a solution, the concentration of the chloride in the antimicrobial agent is not particularly limited and it is suitably set in accordance with the type or Volubility, etc., of the chloride, but a range of 1 to 500 g/1 is preferable, and a range of 10 to 400 g/1 is more preferable, and a range of 100 to 300 g/1 is most preferable. The ratio of the silverchloro complex salts to the chloride in accordance with the present invention is not particularly limited as long as it is in a predetermined range which allows the antimicrobial agent to effect the antimicrobial properties, and a weight ratio of 1:5 x loB to l:2 is preferable, and 1:1000 to i: i07 is more preferable. The third antimicrobial agent in accordance with the present invention may be in the form of a solution, for example, such as an aqueous solution, or, for example, a solid such as a powder. Further, the third antimicrobial agent in accordance with the present invention may contain other ingredients, as required, in addition to the silver-chloro complex salts and the chloride.

The third antimicrobial agent in accordance with the present invention can be adapted to effect the antimicrobial treatment on various kinds of target objects. The target objects which can be treated by the

antimicrobial treatment of the third antimicrobial agent in accordance with the present invention includes various industrial products and home appliances employing such raw materials as resin, fiber, paper, wood, cement, mortar, plaster, unwoven fabric, felt, and leather, and also concrete walls, floor, and ceramic products. The antimicrobial agent is to be effected on the target objects themselves, and as such, the target objects include those objects, for example, such as cosmetics or builder in the form of a powder on which the antimicrobial properties are effected by suitably mixing the third antimicrobial agent in accordance with the present invention therewith.

Further, in the case where the third antimicrobial agent in accordance with the present invention is, for example, chlorides of organic compounds, such as benzalkonium chloride, it is possible to effect the antimicrobial properties which are particularly effective on target objects having a complicated surface structure such as small voids. Examples of the target objects having small voids include, for example, walls, floors, ceilings, joints of tiles, which are made from cement, mortar, or plaster, etc.; walls, floors, ceilings, and furniture, which are made from wood, etc.; and filters made from unwoven fabric or felt, etc.

- 100 When the third antimicrobial agent in accordance with the present invention is a solid, it can be used, for example, by containing it in a powder such as a powder detergent. Further, when the third antimicrobial agent in accordance with the present invention is a solid, it can be used to obtain resin or fiber having antimicrobial properties, for example, by kneading it with resin or fiber, etc. The third antimicrobial agent in accordance with the present invention may be used to treat target objects, for example, by washing the target object with a powder detergent or powder laundry supplement containing the third antimicrobial agent in the form of fine particles, by soaking the target object in the solution of the third antimicrobial agent, by spraying the solution of the third antimicrobial agent on the target object, directly applying the third antimicrobial agent on the target object, by applying the third antimicrobial agent on the target object in the form of a solution or a mixture with a creamy substance, and by wiping the target object with a cloth, etc., which has absorbed the third antimicrobial agent. The method of producing the third antimicrobial agent in accordance with the present invention is not particularly limited, and the third antimicrobial agent

- 101 -

can be produced by the process of preparing a solution by mixing the silver and/or silver compound, chloride, and solvent such as water, or in the case where the antimicrobial agent is a solid, by the additional process of removing the solvent from the solution by evaporation, etc. The silver used herein is the silver metal. Also, the silver compound is not particularly limited as long as it can supply the silver ion by dissociation, and may be, for example, silver salts such as silver chloride, silver sulfate, and silver nitrate.

The temperature in the process of preparing the solution by mixing the silver and/or silver compound, chloride, and solvent such as water may be suitably set and is not particularly limited, but a range of 5 to 95 C is preferable. Further, the temperature in the process of removing the solvent by evaporation, etc., may be suitably set and is not particularly limited, but a range of -20 to 900 C is preferable.

The order of mixing the silver and/or silver compound, chloride, and solvent such as water in the process of preparing the solution of these compounds is not particularly limited, and, for example, it may be conducted, for example, by the method of dissolving the chloride in water to prepare an aqueous solution, and by

adding and mixing silver and/or silver compound therein.

As described, the third antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and the chloride for stabilizing the silver-chloro complex salts, wherein the chloride has at least one of (I) the property capable of existing as a supersaturated aqueous solution for 24 hours or longer even in the presence of a crystal nucleus at least at room temperature, and (II) the property capable of being decomposed when dissolved in water.

By the chloride having at least one of the foregoing properties, there will be no deposition of crystals such as white crystals, which cause the surface of the target object after antimicrobial treatment to have a rough feel or spoil the appearance, even when the antimicrobial agent is dried and the ingredients therein are concentrated after the antimicrobial treatment. Further, even though there are cases where a transparent residue of an irregular shape remains on the surface of the target object, it is either the chloride which exists in the supersaturated state, or a compound which was decomposed by being dissolved and is different from the chloride. Such a residue does not cause the target object to have a rough feel or does not spoil the appearance, thus maintaining the feel or appearance of the target

object. Further, the antimicrobial agent including, for example, polyaluminium chloride among the foregoing chlorides has the property of generating colloid hydroxides in the aqueous solution, and the colloid hydroxides absorb and disperse the fine particles of the silver chloride in the aqueous solution, thus localizing the fine particles of the silver chloride which demonstrates the antimicrobial properties. As a result, it is possible to effect superior antimicrobial properties compared with the conventional antimicrobial properties when the target object is, for example, a liquid such as foul water or waster fluid.

Further, the antimicrobial agent including, for example, chlorides of organic compounds such as benzalkonium chloride among the foregoing chlorides can reduce the surface tension of the antimicrobial agent solution and thus can increase the permeability with respect to the target object. As a result, it is possible to effect the antimicrobial properties which are effective with respect to target objects having a complicated surface structure such as small voids.

The following will describe the third antimicrobial agent in accordance with the present invention in more detail based on Examples and Comparative Examples, which

by no way limit the present invention. Note that, various testing methods in the following Examples and Comparative Examples are as follows.

Method of Confirming Presence or Absence of White Crystals> The following method was employed to confirm presence or absence of white crystal deposition on the surface of the target object after antimicrobial treatment by the antimicrobial agent. The undiluted solution and a 100 times diluted solution were each sprayed on a glass petri dish having a diameter of 9 cm in the concentration of 10 pl/cm2, which was then dried at 30 C for one day. After dried, presence or absence of white crystal deposition on the surface of the glass petri dish was confirmed by visual inspection.

cpo.ato juice deodorant effect test> Potato was squashed in a juicer and 100 ml of the juice was poured respectively into Erlenmeyer flasks each having a volume of 200 ml. The antimicrobial agent was then added to the respective juice in the silver concentrations of 0.2 mg/1, 1.0 mg/1, and 5.0 mg/1, and after sufficient stirring, the mixture was allowed to age at 20 C. The odor of each potato juice after a predetermined time period was evaluated by the sensory test by Len testers to determine the average value of the

! - 105 -

evaluation values of the sensory test, which indicate the degree of odor. The evaluation values of the sensory test were given in five levels: 5 "no odor", 4 "slight odor", 3 "weak odor", 2 "odor", and 1 "strong odor".

Antimicrobial Property Tests To a 50 ml centrifuge tube was added 10 ml of a suspension liquid which contained 7.0 x 105 CFU/ml of MRSA in a 1/1000 diluted triptosoyabouillon medium (provided by NISSUI PHARMACEUTICAL Co., Ltd.), and the antimicrobial agent was added therein in the silver concentration of 0.1 mg/l. Then, while rotating it at 150 rpm, the suspension liquid was incubated at about 25 C for a predetermined time period and the number of bacteria in 1 ml of the suspension liquid was counted by the following bacteria counting method. Also, for comparison, the same operations were performed without adding the antimicrobial agent.

Antimicrobial Treatment Effect Test by Spraying> A diluting solution which had been diluted to have the concentration of the antimicrobial agent in the silver concentration of 1.0 mg/l was sprayed on a perti dish of the size 9 cm in the concentration of 1 pl/cm2 and dried thereon, which was then stored for 3 days at 20 C. On the petri dish was dropped 0. 5 ml of a suspension liquid which contained 5.0 x 106 CFU/ml of MRSA

- 106 -

ln a 1/lOOO diluted triptosoya bouillon medium. Then, the petri dish was covered with a sterilized film of 4.5 cm x 4.5 cm, which was allowed to age for 24 hours at 25 C while maintaining a relative humidity of 100 A. Thereafter, 5 ml of a 1/lOOO diluted triptosoyabouillon medium was added and the suspension liquid treated by the antimicrobial treatment was recovered. The number of bacteria in 1 ml of the suspension liquid which was treated by the antimicrobial treatment and thus recovered was then counted by the following bacteria counting method. Also, for comparison, the same operations were performed without adding the antimicrobial agent.

permeability Confirmatory Test of Antimicrobial Agent> 100 Al of an aqueous solution which had been prepared by diluting the antimicrobial agent 100 times with pure water was delicately dropped on a petri dish made of polystyrene, and the diameter (mm) of the droplet was measured after 1 minute. The diameter was used as a measure of indicating permeability. Further, the surface tension (dye/cm) of the aqueous solution at 20 C was measured using an automatic surface tension balance (product name: "automatic surface tension balance K1OST" provided by Crus Company). The permeability of the antimicrobial agent was judged high with a larger

- 107 diameter of the droplet, or with a lower surface tension.

Also, for comparison, the diameter and surface tension of water, instead of the antimicrobial agent, were measured.

bacteria Number Counting Methods A suspension liquid, or a diluting solution which had been prepared by diluting the suspension liquid with 1/1000 diluted triptosoyabouillon (provided by NISSUI PHARMACEUTICAL Co., Ltd.) was prepared. 1 ml of the suspension liquid or diluting solution was placed on a petri dish of the size 9 cm. Then, to the petri dish was added 20 ml of a standard agar medium (provided by NISSUI PHARMACEUTICAL Co., Ltd.) which had been sterilized by an autoclave and cooled to 40 C. The medium was stirred sufficiently and allowed to age to a solid.

* After incubating the petri dish for 24 hours at 36 C, the number of colonies was counted to calculate the number of bacteria (CFU/ml) in 1 ml of the suspension liquid.

[Example 20]

An aqueous solution was prepared as the third antimicrobial agent in accordance with the present invention to have the silver-chloro complex salts in the silver concentration of 0.13 g/1 and the polyaluminium chloride as the chloride in accordance with the present invention in the AlCl3 equivalent concentration of 100 g/1

- 108 Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

Then, the deodorant effect of the antimicrobial agent with respect to the potato juice was confirmed by the foregoing confirmatory method. The results are shown in Table 13.

Further, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial property test. The results are shown in Table 14.

[Example 21]

The same operations as in Example 20 were performed to obtain the third antimicrobial agent in accordance with the present invention except that the silver-chloro complex salts in the silver concentration of 0.08 g/l, and benzalkonium chloride instead of the polyaluminium chloride were used.

Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

- 109 Further, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial property test. The results are shown in Table 14.

Also, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial treatment effect test by spraying. The results are shown in Table 15.

Further, the permeability of the antimicrobial agent with respect to the target object was confirmed by the foregoing permeability confirmatory test for the antimicrobial agent. The results are shown in Table 16.

[Example 22]

An aqueous solution was prepared as the third antimicrobial agent in accordance with the present invention to have the silver-chloro complex salts in the silver concentration of 0.08 g/l, and polyaluminium chloride as the chloride in accordance with the present invention in the AlCl3 equivalent concentration of 133 g/1. Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

- 110 [Comparative Example 25] The same operations as in Example 20 were performed to obtain a comparative antimicrobial agent except that the aqueous solution was prepared to have the silver-

chloro complex salts in the silver concentration of 0.50 g/l and the sodium chloride of 330 g/l.

Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

Then, the deodorant effect of the antimicrobial agent with respect to the potato juice was confirmed by the foregoing confirmatory method. The results are shown in Table 13.

Further, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial property test. The results are shown in Table 14.

Also, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial treatment effect test by spraying. The results are shown in Table 15.

Further, the permeability of the antimicrobial agent with respect to the target object was confirmed by the

foregoing permeability confirmatory test for the antimicrobial agent. The results are shown in Table 16.

[Comparative Example 26] The same operations as in Example 20 were performed to obtain a comparative antimicrobial agent except that the aqueous solution was prepared to have the silver-

chloro complex salts in the silver concentration of 0.50 g/l and the ammonium chloride of 250 g/l.

Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

Further, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial property test. The results are shown in Table id.

Also, the antimicrobial effect of the antimicrobial agent with respect to MRSA was examined by the foregoing antimicrobial treatment effect test by spraying. The results are shown in Table 15.

[Comparative Example 27] The same operations as in Example 20 were performed to obtain a comparative antimicrobial agent except that the aqueous solution was prepared to have the silver

chloro complex salts in the silver concentration of 0.08 g/1 and the sodium chloride of 330 g/1.

Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

[Comparative Example 28] The same operations as in Example 20 were performed to obtain a comparative antimicrobial agent except that the aqueous solution was prepared to have the silver-

chloro complex salts in the silver concentration of 0.08 g/1 and the ammonium chloride of 250 g/1.

Then, presence or absence of white crystals on the surface of the target object after antimicrobial treatment by the antimicrobial agent was examined by the foregoing confirmatory method. The results are shown in Table 12.

- 113 2 2 2! u a: V o.. Z Z E" Ed En 3 H Z Z 113 Z Z Z

a:::) u, us u' to us co In H. Z H E H _

En O o 0 0 0 0 0 Abet R=< 03 O O H H E

X _ Ho> =: O O O O OO

oo= o o o o o o o rJ I Z --- - 1O i N H rl (:> r H 3 R;i u _ u u

- 114 As is clear from the results of Table 12, in the antimicrobial treatment using the third antimicrobial agent in accordance with the present invention including polyaluminium chloride or benzalkonium chloride as the chloride, no white crystal but a transparent residue of an irregular shape was observed. Such a residue did not cause the surface of the target object to have a rouge feel or deposition of crystals such as white crystals, and it was considered to be the chloride which was existing in the supersaturated state. Thus, it can be seen that the antimicrobial treatment by the antimicrobial agent of the present invention does not spoil the appearance or feel of the target object. In contrast, in the case where the antimicrobial agents of Comparative Examples 25 to 28 including sodium chloride or ammonium chloride were used, white crystals deposited on the surface of the target object, thus spoiling the appearance or feel.

- 1 is -

u} o Gin - 111 I O O N

EN - u, 11) i) 0 __ __

tl) O O o N r r u, ui u, at _ __ _ __ g O.. _ 0 E" H U) Cat O O O O O AH a ARIA;3

- 116 It can be seen from the results of Table 13 that the potato juice after antimicrobial treatment by the third antimicrobial agent in accordance with the present invention including the polyaluminium chloride did not display any odor even after 21 days by the addition in the silver ion concentration of not less than 1.0 mg/l.

Thus, it can be seen that the third antimicrobial agent in accordance with the present invention including polyaluminium chloride can demonstrate superior antimicrobial properties compared with the conventional antimicrobial agents.

- 117 -m _ =3: o o o o D: D o n X it O LD O 0 0 U O

O Z X O X X X

It C Z la D o o o o EN H O

=- r O o C1 o H D3 O O O O O

.e L Act O "l H N H HO ED

5 oa =

- 118 Table 15

AMOUNT OF NUMBER OF BACTERIA

ANTIMICROBIAL AGENT (CFU/ml) ADDED (mg SILVER/l) EXAMPLE 21 1.O O.O

EXAMPLE 25 1.0 0.0

COMPARATIVE 1.O O.O

EXAMPLE 26

NO ADDITION 0.0 4.6 x 105 Further, as it can be seen from the results of Table 14 and Table 15, the third antimicrobial agent in accordance with the present invention has the antimicrobial properties after 24 hours from the start of the antimicrobial treatment with respect to MRSA, and in the antimicrobial treatment by spraying, the number of bacteria was reduced to 0.0 CFU/ml, thus showing superior antimicrobial properties. Also, as is clear from the results of Table 14, the third antimicrobial agent in accordance with the present invention can reduce the number of bacteria immediately after the start of antimicrobial treatment with respect to MRSA. This shows that the third antimicrobial agent in accordance with the present invention has the antimicrobial properties of superior immediate action, i.e., superior disinfecting ability compared with the antimicrobial agents of Comparative Examples 25 and 26. In particular, the third

- llg -

antimicrobial agent in accordance with the present invention including benzalkonium chloride as the chloride is especially superior in immediate action.

Table 16

DILUTION FACTOR DIAMETER OF SURFACE TENSION

(TIMES) DROPLET (mm) (dye/cm) EXAMPLE 21 100 12.8 30.4

COMPARATIVE 100 7.2 71.6

EXAMPLE 25

WATER 7.1 72.7

It can be seen from the results of Table 16 that in the third antimicrobial agent in accordance with the present invention including benzalkonium chloride as the chloride, the diameter of the droplet dropped on the petri dish is larger than that of the antimicrobial agent of Comparative Example 25 or water, and the surface tension is lower. This shows that the third antimicrobial agent in accordance with the present invention including benzalkonium chloride has higher permeability with respect to the target object compared with the conventional antimicrobial agents.

The following will describe a fourth antimicrobial agent in accordance with the present invention in detail.

The antimicrobial agent of the prior application (Tokokaibei 10-182326) includes the silver-chloro complex salts.

- 120 However, the antimicrobial agent of the prior application is produced first by preparing an aqueous solution which contains chlorides of ammonium chloride, alkali metal, or alkali earth metal as the chloride ion, and then by adding the silver chloride or silver metal in the aqueous solution and dissolving it therein as the silver-chloro complex salts. Thus, the foregoing antimicrobial agent is produced, stored, and used in the form of a solution, i.e., a liquid. Therefore, the foregoing antimicrobial agent cannot be stored or used in a solid state by mixing it with a powder such as a powder detergent. Further, since the antimicrobial agent of the prior application is not solid, it cannot be used in the form of fine particles by pulverizing it. Namely, in manufacture of various industrial products or home appliances made from resin or fiber, etc., it is difficult to contain the antimicrobial agent in the resin or fiber by first pulverizing and then kneading the antimicrobial agent.

In general, antimicrobial agents which include the silver-chloro complex salts have sustained antimicrobial properties and the superior property of retaining the antimicrobial properties even when, for example, the surface of the target object is covered with dirt, etc.,

121 - or washed repeatedly. However, since the antimicrobial agent of the prior application is in the liquid form, it is difficult to contain the antimicrobial agent in the target object, for example, by kneading, thus limiting the use.

In order to solve the foregoing problems, a fourth antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and the chloride for supplying chloride ion to stabilize the silverchloro complex salts, and is in the solid form.

The silver-chloro complex salts included in the fourth antimicrobial agent in accordance with the present invention are not particularly limited as long as it is a salt having the complex ion structure as represented by the foregoing structural formula (l). Also, the counter ion (cation) is selected according to use and is not particularly limited.

The chloride included in the fourth antimicrobial agent in accordance with the present invention, which supplies chloride ion to stabilize the silver-chloro complex salts may be, for example, various chlorides as exemplified as the chlorides of the first antimicrobial agent. The ratioof the silver-chloro complex salts to the chloride for supplying chloride ion in accordance with

- 122 À_he present invention is not particularly limited as long as it is in a predetermined range which allows the antimicrobial agent to effect the antimicrobial properties without generating the silver chloride by the silver-_hloro complex salts which became unstable, but a range which would make the proportion of the silver-

_hloro complex salts higher than the weight ratio of l:lOa s preferable. The proportion of the silver-chloro complex salts below this range is not preferable since the amount of antimicrobial agent added needs to be ncreased in this case and due to the fact that the concentrations of the chloride and other ingredients need _o be diluted to have a practical range, which recess- ates diluting the antimicrobial agent to have a significantly low silver-chloro complex salt _oncent_ation. More specifically, the weight ratio in a ange Of 1:105 to 1:10 is preferable, and a range of À:: 1000 o 1:50 is more preferable, and a range of 1:200 o 3:2 0 is further preferable. Note that, when the proportion of the silver-chloro complex salts exceeds the -oregoing ranges, the silverchloro complex salts may become -instable.

In the case of using the fourth antimicrobial agent -n accc-dance with the present invention, for example, by -ontair_ng it in a powder detergent, etc, the mixed

- 123 -

ratio of the antimicrobial agent is not particularly limited and it is suitably set according to potency such as the cleansing ability, etc., of the detergent, and type or amount of the target object. For example, when the antimicrobial agent is used by containing it in a powder detergent and diluting it 100 times in washing, the proportion is to fall in a range which would maintain the antimicrobial properties in use, and a range of 0.001 to 10 percent by weight is preferable, and a range of 0.01 to 2 percent by weight is further preferable in pure silver content. Note that, in this case, in order to effect superior sanitizing and antimicrobial properties in washing, the concentration of the antimicrobial agent in the cleansing solution is preferably not less than 0.01 ppm in the silver concentration.

The fourth antimicrobial agent in accordance with the present invention may include other solid components as required in addition to the silverchloro complex salts and the chloride.

The powder which can be used by adding and mixing the fourth antimicrobial agent in accordance with the present invention is not particularly limited as long as the powder requires antimicrobial properties in use, and it includes, in addition to the powder detergent, for example, a laundry supplement, surfactant, enzyme,

12, :uoescnt br--ht-ne-, anti-recoiling agent, bleaching __en=, -:am stabilize-. foam Inhibitor, softening agent, s lu^il: er, th:_kener emulsifier, perfume, and pigment, ^:c., o al pc-de-y arms.

Ails:, the powder-^hich is used by adding and mixing :-e _nt:-icob_-1 age_ therein may further include an _ iep:: age-- or -isinfe_tant having antimicrobial --opert:_s. Fu- he-,::ne fourth ant-microbial agent in _ coda-:- it- the present inversion may also be added --d mix-- w-th Ether solid substances such as a solid s:ap, i- adcit_:n to.:-e powder.

Th -curt- artim:_robia agent in accordance with -a res-nt invent-on may be added to and mixed with the -:recoi- powders, eta, for example, by directly adding _d -om: eneous_y mix:-,g the ant-microbial agent, after _=epcri-_ its -ll-eruent, w-th -he powder by stirring ^:-h -_xe-. e:_., oby adding _he antimicrobial agent _- atria-:- to - sclut:on dissolving a powder such as a --_e-ge-:, and:he- doling by evaporation, etc. Oh_ o-rt:- ar_im_-robia: agent in accordance with :-e re--nt ir-;en-ior being a sol-d, can be used to _a-n, -fir fixable, a-:imicrcial resin or antimicrobial :be- b--:<nead--g -t With resin or -iber. The method of :_eacin the urea -atimicrobial agent in accordance --:_h th- prose-- nve=ion, -or example, with resin or

fiber is not particularly limited, and it may be performed, for example, by pulverizing the fourth antimicrobial agent in accordance with the present invention into fine particles, which are then mixed with a raw material in manufacture of resin or fiber.

With the fourth antimicrobial agent in accordance with the present invention, antimicrobial treatment of various target objects is possible. The target object which can be subjected to the antimicrobial treatment of the fourth antimicrobial agent in accordance with the present invention includes various industrial products and home appliances which use the raw materials of resin, fiber, paper, and leather, etc., building materials such as a concrete wall or floor, and ceramic products. The antimicrobial agent is to be effected on the target objects themselves, and as such, the target objects nclude those objects, for example, such as cosmetics or builder of in the form of a powder on which the antimicrobial properties are effected by adding and mixing the fourth antimicrobial agent in accordance with the present invention.

The target object may be treated by the fourth antimicrobial agent in accordance with the present invention, for example, by washing the target object with a powder detergent or powder laundry supplement, etc.,

- 126 which- includes tee Fourth antimicrobial agent in a_co-_ance with tk- present invention in the particle form, or by on=air-ng the fourth antimicrobial agent in a_co--ance with the present invention which has been p-'lveized i- resin or fiber by kneading in manufacture o t..- tcrge abject made of resin or fiber.

producing me hod of the fourth antimicrobial agent i- ac orcance w-th:he present invention includes a step ( irs: step) of preparing a mixture by mixing the silver a-d/c- solver compclnd, chloride, and water, and a step (,ecc-d step c removing water from the mixture.

-pecif'-aly, _he producing method of the fourth atir-crobia_ sager in accordance with the present ive-:ior ir_ludes, for example, () a method in which an a_uac-_s Tic- mix -,re is prepared by mixing the silver a-d/csolve- comp und, chloride, and water, and then water is -emoveo from the aqueous solution by e-:apc-at-on, and (' a method in which water is added to the silver a-1/cr silver compound and the chloride in the amou-- which -an make a pas e of the silver and/or silver clo-:de an_ tee Chloride by wetting, and then after p-ep=-ing a hcmog_nous mixture by mixing, water is remox--d ror._he mixture Ev evaporation.

-with tee me-hod (a) of the two methods as exem-if-ed oo-e, -:e sil:erchlo-o complex salts can be

- 127 -

prepared by the reaction in a paste state, i.e., in the solid phase state, without taking the aqueous liquid form. According to the method (2), the amount of chloride which contributes to stabilizing the silver-chloro complex salts can be increased compared with the method (1) which takes the aqueous liquid form, thus having the advantage of increasing the concentration of the silver-

chloro complex salts compared with the method (1).

Further, in the method (2), since it does not require an anticorrosive concentrator which is required for removing water from the aqueous solution in the method (1), there is an advantage of reducing the manufacturing cost. Thus, in the foregoing two methods, the method (2) is more preferable. The silver mixed in the first step is a silver metal. Further, as the silver compound mixed in the first step, for example, other than silver chloride, any silver compounds may be used, except silver salts such as silver sulfide, silver selenide, silver telluride, silver iodide, and silver bromide, which have lower solubility than silver chloride. In industrial applications, as the silver and silver compound, it is further preferable to mix the silver salts. Further, among the silver salts, silver chloride is more preferable.

- 128 2n tee first step, the concentration of the silver ar-/or s__ver chloride in the aqueous solution, for ex_=pl^, --hen the mixture takes the aqueous form as in th_ methc- (1) is not particularly limited.

urt-er, even though the concentration of the chloride _n the aqueous solut on when the mixture takes th- a=ec_s form as in tee method (1) is not particularly 1-.-ted, -ange of _ to 40 percent by weight is pr- erabl_, and a range of 5 to 30 percent by weight is mc-- Are -rable, and a range of 10 _o 20 percent by we:-ht is -ur_her preferable.

Cn t-- othe- hand, Then the mixture takes the paste for, for example, as i- the method (2), the proportions of silver nd/or silver _ompourd, chlor de, and water are nc: part-_1larly limited as long as they are within a rat he by -Munich tile advantages of the method (2) can be ot:air-d; however, th- proportion of chloride is pr--erabl-.- in a range of not less than 1.3 in weight ra:-o whe- the weight ratio o the silver and/or silver cc-?o=nd s 1. Also, the proportion of water is pr_-erabl-. in a - ange c10 to 100 in weight ratio when th_ weigh: ratio of the silver and/or silver compound is 1. Tine --orking temperature of the first step is not pa-:ic-la-:y limited but a range of 60 to 110 C is

further preferable. Further, the working temperature in the second step is not particularly limited but a range of 20 to 200 C is further preferable.

The order of mixing the silver and/or silver chloride, chloride, and water in the first step is not particularly limited, and, for example, it may be performed by dissolving the chloride in an aqueous solution and adding and mixing the silver and/or silver compound therewith, or by adding and mixing the silver and/or silver compound with a mixture of the chloride and water which has been prepared beforehand, which is then further added and mixed with another mixture of the chloride and water.

When the mixture is obtained in the aqueous liquid form, water may be removed from the mixture in the second step by concentrating the mixture under reduced pressure at room temperature or under applied heat using, for example, a rotary vacuum evaporator, and then evaporating the mixture to desiccate it by drying at room temperature or under applied heat. Further, when the mixture is obtained in the paste form, the mixture may be evaporated to desiccate it by drying at room temperature or under applied heat.

According to the fourth antimicrobial agent in accordance with the present invention, the water-soluble

- 130 -

silver-chloro complex salts having a sustained anim _robial property can be produced by the reaction of the silver ar._/o- silver compound with the chloride at a predetrminec ratio in the first step. Further, the ch'orie Was the function of stabilizing the product si've-chlorc complex salts. Further, in the second step, rh- fourth a-imicrbial agent in accordance with the preset_ inve- icn can be obtained in a solid form by remov -g mate- from:he mixture.

e ol_Dwing will explain the mechanism by which chic s-_ve--c:-:oro complex salts included in the fourth anim-_robia: agent in accordance with the present invention demonstrate the antimicrobial properties with espec to th- targe_ object, and the mechanism by which the c-:oride aces - n the silver--hloro complex salts incluc_d in t:-e four h ant microbial agent in accordance with --e present invention.

C-ne-al:-.-, complex salts of s lver ion demonstrate the c imic--oial roperties on bacteria of various specie- and colds By the presence of silver as the cents_: atom. Among such complex salts, the silver-chloro complex salts, -=nli:<e thiocyanic acid complex salt of silve- or thi_su2fur_c acid, etc., co not include sulfide ion (-:). Th_s, the silver-chloro complex salts do not gener=e a toxic gas by being decomposed by heat or acid,

- 131 -

and do not blacken by forming silver sulfide, and therefore have the sustained antimicrobial property. That is, the silver-chloro complex salts demonstrate the antimicrobial property on the target object in the form of the silver-chloro complex salts, or silver chloride, or silver metal.

In the case of using the fourth antimicrobial agent in accordance with the present invention, for example, for laundry by including it in a powder detergent, since the antimicrobial agent is diluted with water, the concentration of the chloride surrounding the silver-

chloro complex salts is reduced. With decrease in concentration of the chloride, the silver-chloro complex salts become unstable and deposit in the form of fine particles of the silver chloride. Because the surface energy of the surface of fiber products, etc., is high, the fine particles of the silver chloride thus deposited are absorbed on the surface in large number, thereby demonstrating the antimicrobial properties. Note that, there may be cases where crystals grow from the crystal of the absorbed silver chloride acting as the nucleus, but a size of the crystal in this case is around 1 m.

Further, in the case where the fourth antimicrobial agent in accordance with the present invention is, for example, kneaded with resin or fiber, the fine particles

132 - of the silver chloride which dissolved out of the fiber are absorbed again on the fiber surface and the antimicrobial properties are effected on the fiber surface. This phenomenon can be observed by electron microscope photography, etc. Further, the antimicrobial properties of the fine particles of the silver chloride which were absorbed again on the fiber surface are not lost even when washed with water and are stable.

Further, with the producing method of the fourth antimicrobial agent in accordance with the present invention, the silver-chloro complex salts can be formed by mixing the silver and/or silver compound with the chloride in the paste form using a small amount of water, for example, without taking the aqueous form. This allows the amount of chloride which contributes to stabilizing the silver-chloro complex salts to be suitably set within a range which can inhibit conversion of the silver-chloro complex salts into silver chloride, thus further stabilizing the product silver-chloro complex salts.

Further, compared with the antimicrobial agent of the solution form, the amount of the product silver-chloro complex salts can be increased.

As described, the fourth antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and the chloride for

- 133 -

stabilizing the silver-chloro complex salts, and is in a solid form. The antimicrobial agent, being a solid, can be used, for example, by mixing it with a powder such as a powder detergent, or by kneading it in the form of fine particles with resin or fiber, thus having wide use.

Further, by including the chloride for stabilizing the silver-chloro complex salts, stable antimicrobial properties can be obtained.

Further, by setting a ratio of the silver-chloro complex salts to chloride in a range of 1:1000 to 1:50 in weight ratio, a further stable solid antimicrobial agent can be obtained and the content of the silver- chloro complex salts can -be increased, thus improving the antimicrobial properties compared with the antimicrobial agent of a solution form.

According to the producing method of the fourth antimicrobial agent in accordance with the present invention, the solid antimicrobial agent can be obtained by removing water from the mixture which has produced the silver-chloro complex salts from the silver and/or silver compound, chloride, and water. Thus, it is possible to obtain the antimicrobial agent having wide use, for example, which can be used by mixing it with a powder such as a powder detergent, or by kneading it in the form of fine particles with resin or fiber, etc. Further,

ir.-e::ae si:-fer-chloro complex salts produced in the Fixture have -Ike sustained antimicrcoial property and the -hlori_- stak:lizes _he silverchlc-o complex salts, it -s possible obtain the antimicrobial agent having Stable antimiobial properties T-. following will describe the fourth antimicrobial agent:a accc-dance with the present invention and the prcuc_ng me:nod thereof in more detail based on _xapl_s, wh--h however are not to limit the present -nvnt:on in Any ways. Note that, t:- e counting method of cac=er_a and the cor.position of a powder detergent in Example 24 ar_ as follows.

c-acteri- Numbe- Count-ng Method> T-e numb_- of MRSA in a solution was counted by the -ollow_-.g met-oaf.

A so'ut-_n, or a diluted solution which has been Ciliate- with - 1000 diluted riptoso-.-a-bouillon (provided by NIS--I --'CUT--AL Co., Ltd.) was prepared. 1 ml of he sc_-,ton -r diluted solution w_s placed on a petri fish h_-:ing a Diameter- of 9 cm. Then, 20 ml of a standard -gamedium (-ovded by NISSUI PHAR'!ACEUTICAL Co., Ltd.) -h'_h -ad bee seer lized flying an autoclave and then Socked to 4C-C was put in each petri dish. After uf-ic:-nt st:-ring, the medium we_ allowed to age and ol-di I. Aft_- incubating the petri dish for 24 hours at

- 135 37 C, the number of colonies was counted to calculate the number of bacteria in the solution.

<Composition of Powder Detergents To prepare a detergent composition containing the antimicrobial agent, a powder detergent having the following composition was used.

dodecylbenzenesulfonic acid Is percent by weight sodium tripolyphosphate 17 percent by weight sodium silicate lo percent by weight sodium carbonate 3 percent by weight carboxymethyl cellulose l percent by weight sodium sulfate 54 percent by weight [Example 23]

The fourth antimicrobial agent in accordance with the present invention was prepared using the producing method of the fourth antimicrobial agent in accordance with the present invention in which the mixture takes the aqueous solution form in the first step.

933 g of potassium chloride was dissolved in water to prepare 3 1 of an aqueous solution in total weight.

Then, 2.43 g of wet silver chloride (containing equivalent to 1.5 g of pure silver) was stirred, dispersed, and dissolved in the aqueous solution to prepare a mixture as an aqueous solution of the silver-

chloro complex salts. The aqueous solution was then

- 136 conc_ntrate_ under reduced pressure at 80 C using a rotary vacu-_m e-apc ator to obtain a concentrated slurry.

The ^oncentated slurry was dried in air for 8 hours at 050_. The Height Of the dried product after drying was 936 -. The -rind product showed no change in color even when expose to -irect sun light for 10 minutes or conch, thus confi-ning that no silver chloride resided -n t2-- brie- podu_t. The dried product was obtained as the -fourth antimi_obial agent n accordance with the present in-_nt-on in a solid form.

[ExamF:e 24] The fc_rt a-_imicrQbial agent in accordance with the present inversion was produced by the producing mesh-1 of:-e Lou- h ant-microbial agent in accordance with, _he present i-'enicn in which the mixture does not take -he aqueous s lummox form in the first step.

20 c- potassium chloride was made into a powder and -.4 Al _- water was acted and mixed therewith to have a p_ste firm. Then, 2.6 g of wet silver chloride corinins equiva:-nt to 1.6 g of pure silver) was added and fixed I obtai a horogenous mixture (A). Then, 980 g of potass:-'m _hlcide and 60 ml of water were added and komo-=neous:y mixe_ in a other container, to which was then added:he mixture (.), which was mixed therein to cEta:n a ho-ogenous mixtu-= (B). A portion of the mixture

- 137 (B) was collected and exposed to the sun light and the mixture (B) immediately turned to a blue-purple color, thus confirming the presence of silver chloride which had not been changed to the silver-chloro complex salts at the time the collection was made. Thus, the mixture (B) was further dried in air for 8 hours at 105 C. The weight of the dried product recovered after drying was 1003 g.

The dried product did not show any change in color even when exposed under direct sun light for 10 minutes or longer, thus confirming that no silver chloride resided.

This confirmed formation of the silver-chloro complex salts in a solid phase without taking the aqueous solution form. The dried product was obtained as the fourth antimicrobial agent in accordance with the present invention in a solid form. The antimicrobial agent contained the silverchloro complex salts in the silver concentration of 1595 mg/kg (1. 595 x 10-3 percent by weight), and potassium chloride as the remainder of the silver-chloro complex salts.

Antimicrobial treatment was applied on a cloth by the detergent composition which was prepared by adding and mixing the antimicrobial agent powder with a powder detergent having the foregoing composition.

To a 1 l beaker were placed 30 sheets of cloth made of polyacetate, each having a size of 1.8 cm x 1.8 cm.

- 138 Afte adding 500 m of water to the beaker, a detergent compcsiton which -was prepared by mixing 50 mg of the antimicrobial agent and 500 mg of the powder detergent was -urther added, which was then washed for 5 minutes while rotating it. Then, the pieces of cloth were trans-ered to another beaker containing 500 ml of the anti.. crobi_1 agent, which was then rinsed for 5 minutes.

The pieces of cloth were taken out and placed on a s_er::ized Petri dish, and after wind dried, each piece was --dependently transferred to a 50 ml centrifuge tube.

T'ne -eces _. clot- were _hen inoculated with 0.2 ml of an MESA s_spensin liquid containing MRSA in the concentration of 5 x 10/ml in a lOOO times diluted trip,osoya.-ouillo. medium (provided by NISSUI P-ARt'ACEUTI_\L Co. , Ltd.). The pieces of cloth thus inoc__ated we-e processed for 18 hours at room temperature (20 to 25 C). To the centrifuge tube were then added C.85 percent by weight of a common salt and 20 ml c a sc:ution Containing 0.2 percent by weight of Twee- 80 (pc:yoxyet:-ylene sorbitan monooleate), which was then shaken O times to wash out bacteria, and the number of bacteria -n each solution was counted by the foregoing coun:_ng me hod to Determine the average value for the 30 pieces or cloth.

Also, he same operations as above were performed to

count the number of bacteria except that the powder detergent was O g.

Further, the same operations as above were performed to count the number of bacteria without using the antimicrobial agent.

Further, the same operations as above were performed to count the number of bacteria without using the antimicrobial agent and the powder detergent. The results are shown in Table 17.

Table 17

ANTIMICROBIAL POWDER DETERGENT NUMBER OF BACTERIA

AGENT (mg) (mg) __ 50. 500 0.0

50 0 0.0

_ 0 500 4.6 x 105 0 0 4.8 x 105 It can be seen from the results of Table 17 that the antimicrobial treatment can be effected on cloth by washing it using the fourth antimicrobial agent in accordance with the present invention or using the detergent composition containing the fourth antimicrobial agent in accordance with the present invention. In contrast, it can be seen that in the case of washing with the powder detergent alone without the fourth antimicrobial agent in accordance with the present

i--rer_ic-, c_ in the c_se of washing with water alone, c-owt:n c- the noculaed bacteria is observed and no a-- imicr-oia' treatment is ef ected.

The ol2ow-ng wil: describe in detail a detergent, l_uncy --upplement, an a third antimicrobial treatment m_hod i- acorance w- h the present invention.

The etorg_nt and laundry supplement in accordance --oh =he present irvenon can be obtained by containing t:-- slv--cloo complex sales in a Predetermined ratio - a -et_-ge-t c- launc-y supplement having the following c:=pcsit:ons. The sil-ver--hloro _ompex salts a-e not particularly Limited as onc as it is a salt which can supply the complex:on st-_ct-=re as represented by the structural _ Emma:) -n::ne aqueous solution.

-,er_-aly, o=ulex salts of silver ion demonstrate =-imicr:oial properties on bacteria of various species =-1 mold- by th_ prse-_e of silver as the central atom.

=-ons such complex salts, he sil-;er-chloro complex s_:ts, =-ik- t-iocyar - acid complex salt of silver or t- os''lf--ic acid, Sac., do no include sulfide ion (S2-).

-IS, to- silve--clor_ complex salts do not generate a t:xic ga- by being decomposed by heat or acid, or do not t:ackn -y.or-inc silver sulfide, and therefore is s-abl.

- 141 Further, the silver-chloro complex salts, whether it is preserved alone or in the detergent or laundry supplement, do not become unstable by the W light or heat, etc. Also, the silver-chloro complex salts do not generate precipitate of silver chloride even with the presence of chlorine ions which are contained in a thickening agent (described later) as the ingredient of the detergent or laundry supplement, and therefore is very stable.

The silver-chloro complex salts used in the present invention may be included in a liquid detergent in the form of an aqueous solution, or in a liquid laundry supplement. Further, the silver-chloro complex salts may be included in a powder detergent or powder laundry supplement in the form of a solid (powder) which is obtained by evaporating the aqueous solution of the silver-chloro complex salts to dryness. Further, the silver-chloro complex salts may be included in the powder detergent or powder laundry supplement while being supported on a porus material such as zeolite.

The detergent of the present invention refers to those detergents which are composed of a surfactant, as the main component, and additives, and whose primary cleansing action is by the surfactant property. The additives contained in the detergent include, a builder,

- 142 -

e-zyme, fluorescent brightener, anti-recoiling agent, bleaching agent, foam stabilizer, foam inhibitor, softening agent, sol=oilizer, thickener, emulsifier, perfume, and pigment, etc. The detergent may further i-.clude an antiseptic agent or disinfectant having antimicrobial properties.

The surfactant includes, for example, anionic s-_.facta-ts, such as alkylbenzenesulfonate, a-olefin-

s_lfonat-, alkyl sulfa e, polyoxyethylene alkyl sulfate, a- a salt of long--:aain -atty acids and non-ionic s_rfacta ts. As th- nc--ionic surfactants, various non-

inic su-factans as exemplified as the surfactant used i- the second antimicrobial agent in accordance with the present Invention may He used.

The builder includes inorganic builders and organic b-_ilaers. The crga. nic builders may be water soluble or w_-er insoluble. The w-_ter soluble builders may be, for example, phosphates, such as sodium tripolyphosphate, t-isodiu- phosphate, sodium metaphosphate, and sodium p-.ophos-hate; silicates such as sodium silicate; c_rbonat-s, suck- as sodium carbonate, sodium bicarbonate, a-d sodium carbonate oeroxyLydrate; sulfates such as sodium sulfate; and caboxyla.es such as sodium citrate.

T:-e wate- insoluble boulders may be crystalline alumina sodium silicate (zeoli-e), etc.

- 143 The organic builders include an organic chelate builder, polymer electrolytic builder, and organic activating builder. The organic chelate builder may be, for example, aminocarboxylic acids, such as nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA), and their salts; organic acids, such as oxalic acid, tartaric acid, citric acid, gluconic acid, and their salts; cyclocarboxylic acid such as pyromellitic acid and benzopolycarboxylic acid, and their salts; and ether carboxylic acids, such as carboxymethyltartronic acid (CMT), carboxymethyloxysuccinic acid (CMOS), and 2,5-dioxa-1,1,3,A,6,6-hexanehexacarboxylic acid (TMD).

The polymer electrolytic builder may be, for example, oxidized derivatives of synthetic polymer, such as acrylic acid polymer, maleic anhydride polymer, co-

polymer of acrylic acid and maleic anLydride, -

hydroxyacrylic acid polymer, itaconic acid polymer, and epoxysuccinic acid polymer; oxidized derivatives of natural polymer, such as starch, cellulose, and alginic acid. The organic activating builder may be, forexample, aminosulfonate. The enzyme may be, for example, protease, lipase, amylase, and cellulose, etc. as long as its activity is not lost by the silver ion.

- 144 :-e fluarescer brightener may be, for example, de-iv_ ives c b s(tiazinylamino)stilbene sulfonic acid, de-iv_ ives of b-sstyryl biphenyl, derivatives of couma-_n, de- vaives of pyrazoline, and derivatives of napht'-_limide. ^e ant--r-so-2ling agent may be, for example, cabo≤e_hy: cellu:ose, methy' cellulose, hydroxyethyl ce lu_-se, ca-bo=. methyl hydrcxyethyl cellulose, hycro<-propy' celluose, hydroxybutylmethyl cellulose, oo2ye ylenec_ycol, polyvinyl alcohol, polyvinyl py-ro::done, ? <vi-yl acetate (viryl acetate polymer), co-po:-.e- or et-yle-e glycol and et:nylene phthalate, co-

polyme of inyl vrrolidone and vinyl acetate, co-

polyme- o v-.yl su onic acid and sodium acrylate, co-

po ym=- or vi yl aceate and maleic anhydride, co-polymer of vi--.-l pyrli-one and maleic anhvdride, co-polymer of vi.yl--_lfonic aced c d maleic anhyd-ide, and the like.

le__hlg agent may be., for example, sodium pe-bo__e, pe oxvbo-ax, sodium caronate peroxyhydrate, sociu. pe-ox-=y_oph^sphate, perberzoate, ureahydrogen pe_ox2_e comF-und, -..elamine-hydrogen peroxide compound, -itric acid perhy-ate, and socium perborate zinc phtha::_yanir sul:-nate, sodium perborate aluminium phtha:-yanir sulf_nate, and the like. Further, the activ=:2ns acent o the bleachinc agent may be, for

- 145 example, pUthalic anLydride, benzoic anhydride, N. N', N", N" ' tetraacetylglycoluril, and tetraacetylethylenediamine. Alternatively, the stabilizing agent of the bleaching agent may be magnesium silicate, calcium silicate, tin silicate, and the like.

The foam stabilizer may be, for example, diethanol-

amide, long-chain alcohol, amine oxide, carboxy betaine, sulfobetaine, hydroxyalkylamide, alkyleulfoxide, and the like. The foam inhibitor may be, for example, microcrystal wax, silicone, ketones with 18 to 40 carbon atoms, and the like.

The softening agent may be cationic surfactants such as dimethylstearylammonium chloride; monoalkyldimethylamine oxide, high molecular weight polyamine, montmorillonite as the natural mineral, and the 1 ike.

When the detergent in accordance with the present invention is a liquid detergent, a solubilizer may be used f or the purpose of solubi 1 i z ing the s i lver - chloro complex salts. The solubilizer may be, for example, benz enesul f onat e, toluene sul f onate, xylene sul f onat e, urea, ethanolamine, diethanolamine, teiethanolamine, ethyl alcohol, ethylene glycol, propyleneglycol, polyethylene glycol, ethylbenzenesulfonic acid,

isop^?y=er.-enesui-onae, cellosolve (ethyleneglycol monoe hy_t--), ar the like iber t:-e cte_gent i acorc.=nce with the present inve--ior i- l_;uid detergent, the detergent may inclc_e a t-_ck-ne. The thickene- may be, for example, polyr-- comc_unds, such as malic acid polymer, itaconic acid _olyer, cc-po:ymer o viryl r.-.ethyl ether and maleic arhycride, poyprpyleneglycol, polyvinyl alcohol, hydrcyet:y_ celluose, methylhyGroxypropyl cellulose, and L-.-ircxyp-op-1 c_ lulose; inorgnic electrolytes, such as sc_ium s_:fie, sodium chloride, potassium chloride, and -e ike.

her t:-e aete-gent in accorcance with the present inve:ior i- 1-quid cetergent, the detergent may inclc_e an -mulsi-ier he emu:sifier may be, for exam-_e, o--olver f sty-ene and acrylamido, co-polymer of s:-.-re-e c d vinypyrroidore, -inyl acetate polymer, magn -ium steara-, mcog yce-ido, ethyleneglycol mono-_tv- ac ester, ethy:eneglyco1 difatty acid ester, a_ge-:ine, r-^aceou- titarium, anc the like.

-urtne-- wen he detergent _n accordance with the prese-. nv-nt-on -s a iqu-d cetergent, the liquid dete- ent wi_1 "lso:ave the anticc-rosive and sanitizing effec:s by tee &nti-.icrobia1 actic of the silver-chloro comp: x sal:s cont.-ined t:nerein. However, the silver

- 147 chloro complex salts may also be used together with a known anticorrosive agent and disinfectant. The anticorrosive agent or disinfectant may be dehydroacetic acid and its salt, sorbic acid and its salt, isobutyl p-

hydroxybenzoate, isopropyl p-hydroxybenzoate, ethyl p-

hydroxybenzoate, butyl p-hydroxybenzoate, n-propyl p-

hydroxybenzoate, butylhydroxyanisole, butylhydroxytoluene, and the like.

The types of perfume and pigment are not particularly limited.

As the term is used herein, the "laundry supplement" in accordance with the present invention refers to those supplements which are used before, during, or after washing for the purpose of enhancing the cleansing ability of the detergent, or, for the purpose of applying other treatment on, for example, fiber products, other than washing. The other treatment includes, for example, bleaching, brightening, softening, sizing, and removal of alkali component. The laundry supplement of the present invention includes, for example, a presoak, water softening agent, pretreatment agent, bleaching agent, brightener, souring agent, softening agent, sizing agent, and the like. The laundry supplement may further include a builder, enzyme, fluorescent brightener, anti-recoiling agent, bleaching agent, foam stabilizer, foam inhibitor,

148 - softeni.g agent, solubilizer, thickener, emulsifier, -erfume, and pigment, etc. which are contained as the Detergent component in accordance with the present indention. The laundry supplement of the present Invention may further include the sanitizing agent and he ant microbial agent.

Further, as the bleaching agent contained in the Laundry supplement n accordance with the present Invention, other than he bleaching agents as exemplified bove,:-ypochlorite such as sodium hypochlorite, and/or Chlorite such as sod lm chlorite can be used. That is, :he sil-;er-chloro complex salts included in the laundry -upplement in accordance with the present invention are -=able even in the presence of chloride ion. Thus, the aundry supplement n accordance with the present Invention can be used combining the bleaching agent -ontain-ng hypochlorie and/or chlorite, i.e. , a so-

_alled chlorine-containing bleaching agent, and the -ilver-chloro complex salts. As a result, it is possible :o have -he bleaching effect as well as the antimicrobial effect on the target object by the antimicrobial ropert--s of the silver-chloro complex salts.

According to the third antimicrobial treatment in _ccorda-ce with the present invention, the washing target -bject -arget object) such as fiber products are treated

149 - in a solution containing the silver-chloro complex salts.

The solution is preferably a cleansing solution containing the silverchloro complex salts and the surfactant. This allows the target object to be subjected to the antimicrobial treatment as well as washed. That is, the solution preferably includes the silver-chloro complex salts in a cleansing solution containing at least the surfactant and, as required, the laundry supplement, etc. The method of adding the silver-chloro complex salts in the cleansing solution is not particularly limited as long as the sanitizing and antimicrobial effect is effected on the washing target object. For example, it is possible to adopt a method of directly putting into the cleansing solution, a method of spraying onto the washing target object in advance, a method of soaking the washing target object in advance in a liquid containing the silver-chloro complex salts, a method of mixing the silver-chloro complex salts beforehand in the detergent or laundry supplement as a component thereof, and the like. Further, the silver-chloro complex salts may be added to the cleansing solution at any time between start and end of washing. Note that, a dewatering process may be performed in washing.

- 150 The mixed ratio of the silver-chloro complex salts contained in the detergent to laundry supplement in accordance with the present invention is not particularly limited, and the silver-chloro complex salts are added in a range which would sustain the antimicrobial properties when used by being diluted several tens to several thousand times during washing, etc. In order to effect superior disinfecting and antimicrobial properties, a silver concentration of not less than 0.1 ppm is preferable. The concentration of the detergent and laundry supplement in accordance with the present invention in the cleansing solution is not particularly limited as long as it is within a range by which the disinfecting and antimicrobial properties are effected at the time of washing. However, in order to effect the antimicrobial properties sufficiently, the silver ion concentration of not less than 0.01 ppm in the cleansing solution is preferable. Further, when washing the same washing target object repeatedly, the antimicrobial effect can be obtained at lower concentrations.

The following explains the mechanism by which the silver-chloro complex salts in accordance with the present invention demonstrate the antimicrobial properties on products.

- 151 The silver-chloro complex salts are diluted with water when used in washing, etc., and thus the concentration of the chloride ion decreases. With decrease in chloride ion concentration, the silver-chloro complex salts become unstable and deposit in the Form of fine particles of the silver chloride. Because the surface energy of the surface of fiber products, ec., is high, the fine particles of the silver chloride thus deposited are absorbed on the surface in large -umber.

Note that, there may be cases where crystals grew from the crystal of the absorbed silver chloride acting as the nucleus, but the size of the crystal in this case is around 1 m.

Thus, when washing the washing target object, the silver-chloro complex salts are added to the cleansing solution, and then the washing target object is rinsed as required to fix or anchor the fine particles of the silver chloride on its surface, thereby having the antimicrobial effect on the washing target object.

In this case, the crystals of the silver chloride which was absorbed on the surface and elsewhere of the washing target object are markedly fine particles and thus the surface area is large. As a result, the silver ion easily dissolves out and superior antimicrobial properties are effected. Further, since the silver

152 chloride absorbed on the fiber surface is markedly fine particles, it does not blacken by irradiation of the W light to the level which can be observed by an naked eye.

As described, by utilizing the properties of the silver-chloro complex salts contained in the detergent and laundry supplement in accordance with the present invention, the sanitizing and antimicrobial effects can be easily obtained on the washing target object at the same time as washing while sustaining the antimicrobial properties on the washing target object.

The detergent and laundry supplement in accordance with the present invention can be applied to fibers such as wool, silk, polyamide, polyurethane, and the like.

Further, the applicable fibers may be colored.

The following describes the detergent, laundry supplement, and third antimicrobial treatment method in accordance with the present invention in more detail based on Examples and Comparative Examples without limiting the present invention in any ways. Note that, the detergent aqueous solution and the bacteria number counting method in the Examples and Comparative Examples are as follows.

detergent Aqueous Solution> dodecylbenzenesulfonic acid 20 by weight dodecylpolyoxyethylene ether 7 by weight

- 153 -Odin- m-.xyleesu: onate 6 by weight -rie=nan_:amoni== citrate 10 by weight -sate- 57 by weight acuec-_s solution containing 0.1 percent by weight cf t-- acuec_s olu-ion of the foregoing composition and the sive-chlorc complex salts and/or sodium hypoc:lorite in a predetermined concentration was used as the _-te-ge aquecus solution in the following laundry F- c_sses. cBacte--a Number Cou-.tins Methods The nu.-=er of bacteria in t:-e solution (cleansing solu_-on, r-.sing solution was cclnted by the method of Exam._e 24.

Examp- 2] isnf_-tion c cloth by the silver-chloro complex salt- was performed in the follow fig manner.

n a c-nt-ifu-e tube with a volume of 50 ml was placed a piece of cloth having a s-ze of 1.8 cm x 1.8 cm, and::e Sub_ was sterilized by a. autoclave. The cloth was then inc_ulatec by collecting and placing thereon 0.2 ml o susp-ns-on Liquid cont.-in) g 5 x 104/ml of MRSA in a 10: t-mes diluted trip.osoyabclillon medium.

To "he centrifuge tube was -hen added 20 ml of a detergent a_leous solution containing 1.0 ppm of the silv_--clo-, complex sal s. The c oth was washed for 10

- 154 minutes while rotating the centrifuge tube at 150 rpm, and the supernatant was used as the cleansing solution.

Then, the cloth was transferred to another centrifuge tube containing 20 ml of sterilized water and was rinsed for 10 minutes at 150 rpm, and the supernatant was used as the cleansing solution. The cloth was then taken out and placed on a standard agar medium for incubation at 37 C for 24 hours to confirm presence or absence of MRSA proliferation. The same operation was repeated 3 times to prepare Petri Dish 1, Petri Dish 2, and Petri Dish 3.

In the same manner, the same operation was repeated for detergent aqueous solutions containing the silver-

chloro complex salts in the concentrations of 10.0 ppm and 100.0 ppm, respectively, and for a detergent aqueous solution containing 1.0 ppm of silver-chloro complex salts and 125.0 ppm of sodium hypochlorite (reagent) in the concentration of active chlorine. The results are shown in Table 18.

After washing, the number of bacteria contained in each rinsing solution was counted by the foregoing counting method. The petri dish which contained one or more bacteria was represented by "+", and the petri dish which contained no bacteria was represented by "-".

[Comparative Example 29] The same operation as in Example 25 was performed

without using the silver-chloro complex salts. The results are shown in Tables 18 to 20.

Table 18

SILVER-CHLORO SODIUM PRESENCE OR ABSENCE OF

COMPLEX SALTS CHLORITE BACTERIA

(ppm IN SILVER (ppm IN ACTIVE CONCENTRATION) CHLORINE)

EXAMPLE 25 1.0 0.0 | |

1.0 125.0

10.0 0.0 _

100.0 0.0 _

COMPARATIVE 0.0 0.0 + | +

EXAMPLE 9 l

0.0 125.0 1 _

Tab e 19 SILVER-CHLORO SODIUM NUMBER OF BACTERIA IN

COMPLEX SALTS CHLORITE CLEANSING SOLUTION

(ppm IN SILVER (ppm IN ACTIVE CONCENTRATION) CHLORINE)

_XAMPLE 25 1.0 0.0 9.5.x I02 1.0 125.0 0

10.0 0.0 3.5 x 1o2 100.0 0.0 0

OMPARAT-lE 0.0 0.0 3.3 x 10 EXAMPLE 29.

0.0 125.0 0

Table 20

SILVER-CHLORO SODIUM NUMBER OF BACTERIA IN

COMPLEX SALTS CHLORITE RINSING SOLUTION

* (ppm IN SILVER (ppm IN ACTIVE CONCENTRATION) CHLORINE)

EXAMPLE 25 1.0 O.0 O

1.0 125.0 0

10.0 0.0 0

100.0 0.0. 0

COMPARATIVE O.O O.O 1.5 x 1o2 EXAMPLE 29

0.0 125.0 0

[Example 26]

Antimicrobial treatment by the silver-chloro complex salts was effected on cloth in the following manner.

To a loo ml beaker was added a piece of cloth having a size of 1.8 cm x 1. 8 cm. To the beaker was added 50 ml of a detergent aqueous solution containing the silver-

chloro complex salts and/or sodium hypochlorite in a predetermined concentration, and the cloth was washed for 5 minutes while rotating it. The cloth was then transferred to another beaker containing 50 ml of sterilized water and rinsed for 5 minutes.

The cloth was then taken out and placed on a sterilized petri dish, and after wind dried, transferred to a 50 ml centrifuge tube. The cloth was inoculated with 0.2 ml of an MRSA suspension liquid containing 5 x 104/ml of MRSA in a 1000 times diluted triptosoya bouillon

157 - mediu-, add --as treated for 18 hours at room temperature (20 t2 C). To tee centrifuge tube was added 20 ml of a so -_ticn contain -.g 0. 85 of a common salt and 0.2 of Tw_en 30 oolyox"-ethylenesoritan monooleate), and the bacteria was washed out by shaking the tube 30 times and the -umber Of bacteria contained in the solution was counted by tee ore_oing count-ng -.ethod. Also, the same opera_ior was performed except hat water was used inste_B c tee aqueous solution The results are shown in Table 21.

o==ar_.ive Example 30] :ne ma...- cper--ion as in Example 26 was performed withy-_ using the silver-choro complex salts. The rsul-3 are - known. Table 21.

- 158 Table 21

SURFACTANT SILVER-CHLORO SODIUM NUMBER

COMPLEX SALTS HYPOCHLORITE OF

(ppm IN SILVER (ppm IN BACTERIA CONCENTRATION) ACTIVE

CHLORINE)

_ EXAMPLE 26 ABSENT 5 0.0 0.0

5 125.0 0.0

PRESENT 5 0.0 0.0

5 125.0 0.0

ABSENT 500 0.0 0.0

500 0.0 0.0

COMPARATIVE ABSENT O O.O 1.8 x 106 EXAMPLE 30

0 125.0 2.1 x 106 PRESENT 0 0.0 2.5 x 1o6 0 125.0 1.4 x 106 It can be seen from the results of Table 18 to 20 that when the silver-chloro complex salts are contained in the silver concentration of 1.0 ppm or more, no bacteria existed on the cloth after washing and rinsing, and the cloth was completely sanitized.

It can be seen from the results of Tables 18 to 20 the sodium hypochlorite also has the sanitizing effect.

However, it can be seen from the result of Table 21 that when the detergent aqueous solution does not contain the silver-chloro complex salts, no antimicrobial properties were effected on the cloth after washing and growth of bacteria was observed.

- 1S9 -,rt.ner, it can be seen from the results of Table 21 that:e silverchloro complex salts can demonstrate the antim__robia: ability regardless o presence or absence of the surfac_ant.

The fo lowing will describe one embodiment of disposable sheets in accordance with the present inven on wi h reference to Figs. 2(a) and 2(b) , and Figs. 3 taro_gh 6.

-3 shown In Figs. 2(a) and 2(b), in disposable sheet_ 2 of -he present er. od-men, there are provided noch_s 3 with respect to and in the longitudinal direc_-on of a rectangular sheet so that the sheet 2 can be separated into a right-side part 2R and a left-

side cart 2L, and a tape 4 for sea ing the notches 3 is stuck on the sheet 2 by a pressure sensitive adhesive agent 'not shown) covering the notches 3.

he disposable sheets 1 can be used for beds of perma-ently-- l patients and rmo.-ed only by moving it while he pa--ent laying thereon.

Specifically, -n order to --move the disposable sheets 1, the body c a patient is Burned to the side on the r:ght-si-e part 2R (a- left--ide part 2L) of the sheet 2 to peel off -he tape 4 sea:ng the notches 3. As a result, as shown in Fig. 3, the notches 3 appear. Then, by pulling ha-d the effusive part AL (or right-side part

2R) of the sheet 2 with hands, the left-side part 2L (or right-side part 2R) of the sheet 2 is separated from the right-side part 2R (or left-side part 2L) at the notches 3, thus removing the left-side part 2L (or rightside part 2R) of the sheet 2. Then, the body of the patient is turned to the side from which the left-side part 2L (or right-side part 2R) of the sheet 2 was removed (e.g., on the left-side part 2L of underlying disposable sheets 1) and the right-side part 2R (or left-side part 2L) of the sheet 2 is pulled with hands to remove it.

Since the disposable sheets 1 can be removed while the patient is lying thereon, by placing another sheets under the disposable sheets 1 in advance, the sheets can be replaced while the patient is lying thereon.

Accordingly, it is not required to move the patient from the bed, thus making it possible to replace sheets by a single care giver.

Further, since the notches 3 of the disposable sheets 1 are sealed with the tape 4, urine or sweat of the patient is prevented from seeping out into underlying sheets in use, for example, such as another disposable sheets 1, through the notches 3.

The size of the disposable sheets 1 is suitably adjusted according to the size of the bed to which the disposable sheets 1 are applied, and it is set to have a

size of about 150 cm x 220 cm (width x length), for example.

In order to prevent the sheets from becoming sultry by sweat, etc., the sheet 2 is preferably made from sheets having gas permeability such as paper or unwoven fabric, or gas permeable sheets including additives. As such gas permeable sheets, paper and unwoven fabric are particularly preferable since they are inexpensive and have some absorbency to partially absorb urine or sweat, -to. T e sheet 2 preferably further includes the antimicrobial and deodorizing agent, such as the silver-

hloro complex salts, as additives. As a result, the sheet 2 can have the antimicrobial and deodorizing effects, thus maintaining further cleaner environment.

The sheet 2 preferably further includes a polymer cater absorbent as additives. This ensures to absorb urine or sweat, etc., and prevents urine or sweat, etc., _o seep out into the underlying sheets through the sheet 2. As such a polymer water absorbent, polymer absorbent resin -n the form of fine particles, as represented by "Aquakeep lOSH-NF" (product name, provided by Sumitomo troika Chemicals Co., Ltd.) can suitably be used.

The method of adding the additives in the gas permeable sheet is not particularly limited, and it can

162 - be performed by kneading the additives with the raw material of the gas permeable sheet in manufacture thereof ("kneading method" hereinafter) , or by sandwiching the additives between the gas permeable sheet and another sheet, which are then pasted together ("sandwiching method" hereinafter), or by dissolving the additives with a binding agent to have a solution and then soaking the gas permeable sheet in the solution ("soaking method" hereinafter).

The following will describe the method of adding additives in more detail based on the example of adding the antimicrobial and deodorizing agent and polymer water absorbent. When adding both the antimicrobial and deodorizing agent and the polymer water absorbent by the kneading method, the antimicrobial and deodorizing agent and the polymer water absorbent are added by kneading with the raw material of the gas permeable sheet in manufacture of the gas permeable sheet from its raw material such as paper or unwoven fabric.

As a result, as shown in Fig. 4, the sheet 2 of a single layer structure in which the antimicrobial and deodorizing agent 23 and the polymer water absorbent 22 are dispersed in the gas permeable sheet 21 is obtained.

In this case, as the antimicrobial and deodorizing agent

- 163 23, the antimicrobial and deodorizing agent of a powdery form, for example, such as a silver-chloro complex salt powder can be used. Also, as the polymer water absorbent 22, a polymer water absorbent of a powdery form, for example, such as polymer water absorbent resin of fine particles as represented by "Aquakeep lOSH-NF" (product name, provided by Sumitomo Seika Chemicals Co., Ltd.) can be used.

Note that, to increase the strength of the sheet 2, the sheer of the s ngle structure in which the antimicrobial and deodorizing agent 23 and the polymer water absc_bent 22 are kneaded in the gas permeable sheet 21 is integrated by bending using an adhesive with a resin sheet made of polyethylene, polyester, polypropylene, or polyamide, or a gas permeable sheet (paper or unwoven fabr c) which does not contain the antimicrobial and deodorizing agent and the polymer water absorbent. In this case, the sheet 2 come to have a double layer structure.

Further, in the case where the antimicrobial and deodorizing agent and the polymer water absorbent are added by the soaking method and the sandwiching method, respectively, the following is carried out.

That is, after menu acturing the gas permeable sheet made of paper or unwoven fabric, etc., the gas permeable

- 164 sheet is soaked in a mixture of the antimicrobial and deodorizing agent and the binding agent so as to attach the antimicrobial and deodorizing agent and the binding agent (binder) on the surface of the gas permeable sheet.

As a result, the antimicrobial and deodorizing agent is fixed on the surface of the gas permeable sheet by the binding agent, thereby adding the antimicrobial and deodorizing agent on the gas permeable sheet. In this case, as the antimicrobial and deodorizing agent, the antimicrobial and deodorizing agent of a liquid form, for example, such as liquid silver-chloro complex salts can be used.

Then, the gas permeable sheet adhering the antimicrobial and deodorizing agent thereon is integrated by bonding using an adhesive with a resin sheet such as polyethylene, polyester, polypropylene, and polyamide, etc., or a gas permeable sheet (paper or unwoven fabric) which does not contain the antimicrobial and deodorizing agent while sandwiching the polymer water absorbent therebetween. In this case, as the polymer water absorbent, a polymer water absorbent of a powdery form, for example, such as a polymer water absorbent powder as represented by "Aquakeep lOSH-NF" (product name, provided by Sumitomo Seika Chemicals Co., Ltd.) can be used.

As a result, as shown in Fig. 5, it is possible to

- 165 obtain a sheet 2' of a double layer structure wherein the polymer water absorbent 22 is sandw ched between the gas permeable sheet 21 dispersing the antimicrobial and deodorizing agent 23 therein and the sheet 24 made from a resin sheet or gas permeable sheer.

Note that, the positions of the antimicrobial and deodorizing agent and the polymer water absorbent may be change-. That is, the sheet of the c. ouble layer structure incluc.-ng the antimicrobial and deodorizing agent and the polyme- wate- absorbent can also be obtained by first making a gas permeable sheet containing the polymer water absorbent and then bonding it with a resin sheet or gas permeable sheet which does not contain the polymer water absorbent us-ng an adhesive wh le sandwiching the antimicrobial and deodorizing agent _herebetween. In this case, as the antimicrobial and deodorizing agent, the antimicrobial and deodorizing ages- of a powdery form, for example, such as the powder - ilver-chloro complex salts Can be -'sed.

T-e notches 3 are to allow the sheet 2 to be separated by pulling the sheets 2 -with hands, and they can be, for example, slits or sewing pattern.

The notches 3 are preferably provided along the center line in the longitudinal direction of the sheet 2, i.e., -or example, in such a manner that the distance

from the longer sides of the sheet 2 to the center line is 75 cm when the width of the sheet 2 is 150 cm.

As a result, the two portions on the both sides of the notches 3 of the sheet 2, i.e., the right-side part 2R and the left-side part 2L become equal in size. As described, in order to replace the disposable sheets 1 while the patient is lying thereon, it is required to turn the patient to the right-side part 2R of the sheet 2 and then to the side of the sheets 2 from which the left-side part 2L of the sheet was removed (e.g., on the left-side part 2L of the sheet 2 of underlying disposable sheets 1). By making the right-side part 2R and the left-

side part 2L equal in size, it becomes relatively easier to turn the patient to the right-side part 2R of the sheet 2, and to the portion of the sheets 2 from which the left-side part 2L of the sheet 2 was removed.

The tape 4 covering the notches 3 may be a sheet having the same composition and structure as that of the sheet 2, or, for example, paper or unwoven fabric which has been cut to have a width narrower than that of the sheets 2. The width of the tape 4 is to have a width which can cover the notches 3 and which permits bonding by the pressure sensitive adhesive agent, and it is, for example, about 2 cm.

The pressure sensitive adhesive agent is provided

- 167 -

between the sheet 2 and the tape 4 and preferably applied only on the Cape 4. This prevents the pressure sensitive adhesive agent from sticking to the patient when the patient is urned from the righ;-side part 2R of thesheet 2 to _he portion of the sheet 2 from which the left-side cart 2_ was removed when replacing the dispceable sheets:. Note that, the type of the pressure sens- ive adhesive agent -s not particularly limited.

As shc^-n in rig. 6, the d-sposable sheets 1 are preferably _sed as a set o disposable sheets by stacking a plurality of disposable sheets l on one another. With this arrangement, once the patient is laid on the bed, the Disposable sheets can be replaced only by moving the sheets -Chile _he patient is lying thereon. This allots tine --sposa^le sheets 1 to be replaced only by a sing:- care Liver.

The nether c_ disposable sheets 1 stacked is determined _- tine =-_mbe- c disposable sheets 1 which can be re?laced-hi7e he patient is icing thereon. Also, the number o c-sposab:e sheers 1 is selected according to the eriod -A replacing the disposable sheet set since the c sposa_:e sheet set -.eeds to be replaced by moving the patient once all the disposable sheets of the dispcaable street set are Used up. For example, when the number- of c sposa_le sheets is seven, the disposable

- 168 sheet set is replaced every week, which may be convenient. Note that, as shown in Fig. 6, the disposable sheets 1 are preferably stacked with the tape 4 facing upward.

This allows the tape 4 to be easily peeled off when replacing the disposable sheets 1.

The following will describe another embodiment of the disposable sheets and disposable sheet set in accordance with the present invention with reference to Figs. 7(a) and 7(b), and Figs. 8 and 3.

As shown in Figs. 7(a) and 7(b), in disposable sheets 11 of the present embodiment, two rectangular sheet elements 12 and 13 are disposed side by side with their longer sides contacting each other, and a tape 14 is attached on the sheet elements 12 and 13 by a pressure sensitive adhesive agent (not shown) so as to cover a portion of the sheet elements 12 and 13 in contact with each other.

The disposable sheets 11 can be used for beds of permanently-ill patients and removed only by moving it while the patient is laying thereon.

Specifically, in order to remove the disposable sheets 11, the body of a patient bridging over the sheet elements 12 and 13 is turned to the side on the sheet element 12 (or sheet element 13) to peel off the tape 14.

- 169 As a result, as shown in Fig. 8, the sheet elements 12 and 1 become movable independently from the other. Then, by pulling:ze sheet element 13 for sheet element 12) with:-=ncs,:ae sheet element 13 (or sheet element 12) is removed. The-, _he body of the patient is turned to the side from weigh the sheet elements 13 (or sheet element 12) was em,_ed, and the sheet element 12 (or sheet eleme-.c 13) -s pulled with hands to remove it.

mince tee disposable sheens 1: can be removed while the patient -s laying thereon, by placing another sheets under the --sposable sheets 11, the sheets can be replaced -while the patient is lying thereon. Accordingly, it is not required to move the patient from the bed, thus making it pcssile Lo replace sheets by a single care giver. -urther, in the disposable sheets 11, since the portion of t:-e shee- elements 12 and 13 in contact with each Ocher i- covered with the tape 14, urine or sweat of the patient -s prevented from seeping out into underlying sheets in use, for example, such as another disposable sheets 11, l-rough a gap between the sheet elements 12 and 1-.

The siz- of the disposable sheets 11 is suitably adjusted according to the size of the bed to which the disposable sheets 1- are applied, and it is set to have

- 170 a size of about 150 cm x 220 cm (width x length), for example.

In order to prevent the sheets to become sultry by sweat, etc., the sheet elements 12 and 13 are preferably made from sheets having gas permeability such as paper or unwoven fabric, or gas permeable sheets including additives. As such gas permeable sheets, paper and unwoven fabric are particularly preferable since they are inexpensive and have some absorbency to partially absorb urine or sweat, etc. The sheet elements 12 and 13 preferably further include the antimicrobial and deodorizing agent such as the silver-chloro Complex salts as additives. As a result, the sheet elements 12 and 13 can have the antimicrobial and deodorizing effects, thus maintaining further cleaner environment.

The sheet elements 12 and 13 preferably further include a polymer water absorbent as additives. This ensures to absorb urine or sweat, etc., and prevents urine or sweat, etc., to seep out into the underlying sheets through the sheet elements 12 and 13. As such a polymer water absorbent, polymer absorbent resin in the form of fine particles, as represented by "Aquakeep lOSH-

NF" (product name, provided by Sumitomo Seika Chemicals Co., Ltd.) can suitably be used.

- 171 The method of adding the additives in the gas permeable sheet is not particularly l mited, and it can be performed by kneading the additives with the raw material of the gas permeable sheet in manufacture thereof ("kneading method" hereinafter), or by sandwiching the additives between the gas permeable sheet and another sheet, which are then pasted together ("sandwiching method" hereinafter), or by dissolving the additives with a binding agent to have a solution and then soaking the gas permeable sheet in the solution ("soaking method" hereinafter). Note that, the sheet elements 12 and 13 of the gas permeable sheet having added the antimicrobial and deodorizing agent and the polymer water absorbent may be of the form of the sheet 2 as described in the First Embodiment, and, for example, the sheet 2 as shown in Fig. 4 or the sheet 2' as shown in r ig. 5 may be adopted.

The sheet elements 12 and 13 are preferably in the sa..e size. As described, in order to replace the disposable sheets 11 while the patient is lying thereon, it is required to turn the patient to the sheet element 12 and then to the side from which the sheet element 13 was removed (e.g., on the sheet element 13 of underlying disposable sheets 11). By making the sheet elements 12 and 13 equal in size, it becomes relatively easier to

- 172 turn the patient to the sheet element 12, and to the portion from which the sheet element 13 was removed.

The tape 14 may be a sheet having the same composition and structure as that of the sheet elements 12 and 13, or, for example, paper or unwoven fabric which has been cut to have a width narrower than that of the sheet elements 12 and 13. The width of the tape 14 is to have a width which can cover the portion of the sheet elements 12 and 13 in contact with each other, and which permits bonding by a pressure sensitive adhesive agent, and it is, for example, about 2 cm.

The pressure sensitive adhesive agent is provided between the sheet elements 12 and 13 and the tape 14 and preferably applied only on the tape 14. This prevents the pressure sensitive adhesive agent from sticking to the patient when the patient is turned from the sheet element 12 to the portion from which the sheet elements 13 was removed when replacing the disposable sheets 11. Note that, the type of the pressure sensitive adhesive agent is not particularly limited.

As shown in Fig. 9, the disposable sheets 11 are preferably used as a set of disposable sheets by stacking a plurality of disposable sheets 11 on one another. With this arrangement, once the patient is laid on the bed, the disposable sheets 11 can be replaced only by moving

the s-.eets while te patient is lying thereon. This allows the disposable sheets l to be replaced only by a single care giver.

ye number of disposable sleets 11 stacked is deters ned by the number of disposable sheets 11 which can be replaced-while the patient is lying thereon. Also, the number o- disposable sheets 11 is selected according to the period of replacing the dispceable sheet set since the disposable sheet set needs to be replaced by moving the patient Sync- a1 the disposable sheets 11 of the disposable sheet set are used up. for example, when the number of disposable sheets 11 is seven, the disposable sheet set -s replaced every week, which may be conver ent.

N_te th=_, as s:-own in Fig. 9, =he disposable sheets 11 are preferably stacked w th the -ape 14 facing upward.

This allows The tape 14 to be easily peeled off when replac-ng the disposable sheets 11.

-:-e invention being thus described, it will be obvious that he sate way may be -raried in many ways.

Such variations are not to be regarded as a departure from tee sui'-t and scope of the invention, and all such modif-ations as would be obvious -o one skilled in the art are interred to be included wi hin the scope of the following cla-ms. -

- 174 INDUSTRIAL APPLICATIONS OF THE PRESENT INVENTION

As described, a first antimicrobial agent in accordance with the present invention includes silver-

chloro complex salts and oxidizing agents.

With this constitution, it is possible to provide an antimicrobial agent having both immediate and sustained properties with respect to disinfection as well as deodorizing, having a wide disinfecting spectrum, capable of preventing resistant bacteria and having good safety, capable of sustaining sufficient stability even in a medium or environment where sulfides coexist, having a reasonable price, and having superior deodorizing action as well as antimicrobial and mildew proofing action.

As described, a producing method of the first antimicrobial agent in accordance with the present invention is adapted to mix a chloride aqueous solution, silver and/or silver compound, and oxidizing agents.

With this method, it is possible to provide an antimicrobial agent having both immediate and sustained properties with respect to disinfection as well as deodorizing, having a wide disinfecting spectrum, capable of preventing resistant bacteria and having good safety, capable of sustaining sufficient stability even in a medium or environment where sulfides coexist, having a reasonable price, and having superior deodorizing action

as well as antimicrobial and mildew proofing action.

As described, a first antimicrobial treatment method in accordance with the present invention is adapted to treat a target object using an aqueous solution which contains the silver-chlcro complex salts in the presence of the oxidizing agents.

With this method, it is possible to provide an antimicrobial agent having both immediate and sustained properties with respect to disinfection as well as decdorizi-g, having a wide disinfecting spectrum, capable of preventing resistant bacteria and having good safety, capable of sustaining sufficient stability even in a medium or environment where sulfides coexist, having a reasonable price, and having superior deodorizing action as -sell as antimicrobial and mildew proofing action.

As described, a second antimicrobial agent in accordance with the present invent-on includes the si:ver-ch:oro complex salts and chlor de for supplying chloride -on, and the second antimicrobial agent further includes compounds having compatibili y with a solvent dissolving the chloride, and more preferably a solvent (p-eferab:y water) whic.n dissolves the chloride.

Thus, as the compounds having compatibility with the solvent which dissolves the chloride capture water or ot:-er solvent, it is possible to reduce the free water or

- 176 solvent which is not chemically and physically captured in the vicinity of the silver-chloro complex salts in the antimicrobial agent solution. As a result, the apparent concentration of the silver-chloro complex salts, which contributes to stability of the silver-chloro complex salts, can be increased. Accordingly, it is possible to reduce the concentration of the chloride ion actually contained in the antimicrobial agent solution while maintaining a chloride ion concentration which is directly required for stabilizing the silver- chloro complex salts. Thus, with the foregoing constitution, it is possible to provide an antimicrobial agent which can easily effect the antimicrobial treatment without diluting the antimicrobial agent solution when using it.

As described, a second antimicrobial treatment method in accordance with the present invention is adapted to treat the target object with the second antimicrobial agent.

Thus, With this method, since it is not required to change the stored concentration of the chloride ion, the antimicrobial treatment can be effected conveniently.

As described, a third antimicrobial agent in accordance with the present invention includes a chloride which has at least one of (I) a property capable of existing as a supersaturated aqueous solution for 24

- 177 -

hours or longer in the presence of a crystal nucleus at least at room temperature, and (II) a property capable of being decomposed when dissolved in water, and the silver-

chloro complex salts.

Thus, with this constitution, by the chloride having the foregoing properties, the chloride does not grow into white crystals, etc., on the surface of the target object even when the chloride is concentrated by the antimicrobial agent wh ch has dried after the antimicrobial treatment, thus preventing appearance or feel of the target object from being spoiled.

As described, a fourth antimicrobial agent in accordance with the present invention includes the silver-chloro complex salts and the chloride, and is a solla. Thus, since the antimicrobial agent is a solid, it is possible to provide an antimicrobial agent having wide use, for example, such as mixing with a powder such as a powder detergent, or kneading with resin or fiber in the form of fine particles. Further, by the silver- chloro complex salts having the sustained antimicrobial property and by the chloride which stabilizes the silver-chloro complex salts, it is possible to provide an antimicrobial agent having stable antimicrobial properties.

As described, a producing method of the fourth

- 178 antimicrobial agent in accordance with the present invention includes the steps of preparing a mixture by mixing the silver and/or silver compound, chloride for supplying chloride ion, and water, and removing water from the mixture.

Thus, since the mixture contains the chloride, the silver-chloro complex salts exist stably even when water is removed from the mixture, thus producing a solid antimicrobial agent having stable antimicrobial properties. As a result, it is possible to provide a producing method of an antimicrobial agent having wide use, for example, such as mixing with a powder such as a powder detergent, or kneading with resin or fiber in the form of fine particles. Further, by the silver-chloro complex salts having the sustained antimicrobial property and by the chloride which stabilizes the silver-chloro complex salts, it is possible to provide a producing method of the antimicrobial agent having stable antimicrobial properties.

As described, a detergent in accordance with the present invention includes the silver-chloro complex salts. Thus, the antimicrobial treatment can be effected on the washing target object without resulting in change in color of the washing target object (target object).

- 17g Furt:^er, the susta ned antimicrob al property can easily be effected in washing. Also, since there is no reaction with the _-gr-dier, ts contained in the detergent, for example, such as -he anionic surfactant and thus the anti-.icrobi_1 ability can be stably maintained, it is poss-ble to Demonstrate washing ark antimicrobial effects at -he same time, among other effects. Further, antiseptic -rfect can be obtained for the detergent.

As described, a laundry supplement in accordance with the present inventon includes the silver-chloro complex sa:_s.

Thus, -or example, when used-ith a softening agent, the antimicrobial treatment car be effected on the washing target ob ect w-thout resulting in change in colc- of tee washing target objec_ (target object) while effe__irg tee softening property. Further, the sustained ant_-icrobial property can be conveniently effected when the often_-g property, etc., is effected. Also, since there is nc react-on with ingredients contained in the laundry s_oplemen., fc example, in the anionic surf_ct=t, and thus the antimicrobial ability can be maintained stably, it is possible to effect the antiicrobi_1 effect, among othe- effects, at the same time when -he softening property, etc., is effected.

Furt er, a isept-c effect can be obtained for the

laundry supplement.

As described, a third antimicrobial treatment method in accordance with the present invention is adapted to treat the target object in a solution containing the silver-chloro complex salts.

Thus' the antimicrobial treatment can easily be effected without resulting in change in color of the target object. Further, the antimicrobial effect can easily be sustained on the target object.

As described, disposable sheets in accordance with the present invention include notches with respect to and in the longitudinal direction of a rectangular sheet so that the sheet can be separated into two, and a tape for sealing the notches is stuck on the sheet by a pressure sensitive adhesive agent covering the notches.

Thus, with this constitution, it is possible to provide disposable sheets which can be removed while a person is lying thereon.

As described, disposable sheets in accordance with the present invention include two rectangular sheet elements which are disposed side by side with their longer sides contacting each other, and a tape is attached on the sheet elements by a pressure sensitive adhesive agent so as to cover a portion of the sheet elements in contact with each other.

Thus, with this constitution, it is possible to provide disposable sheets which can be removed while a person is lying thereon.

As described, a disposable sheet set in accordance with the present invention has the disposable sheets, any of which are stacked one over another.

Thus, with this constitution, it is possible to provide a disposable sheet set which allows a single care giver to replace the sheets when used for beds of permanently-ill patients.

Claims (11)

CLAIMS:

1. An antimicrobial agent including a silver-chloro complex salt and an oxidizing agent.

s

2. An antimicrobial agent according to claim 1, wherein the silver-

chloro complex salt and the oxidizing agent are contained in an aqueous chloride solution.

10

3. An antimicrobial agent according to claim 2, wherein the concentration of the silver-chloro complex salt in the aqueous chloride solution is not less than 0.05 mgA of silver ion equivalent.

4. An antimicrobial agent according to claim 2, wherein the 15 concentration of the silver-chloro complex salt in the aqueous chloride solution is not less than 2.5 mgA of silver ion equivalent.

5. An antimicrobial agent according to any one of claims 2 to 4, wherein the chloride ion concentration in the aqueous chloride solution is not 20 less than 0.02 mold.

6. An antimicrobial agent according to any one of claims 1 to 5, wherein the oxidizing agent is hypochlorite and/or chlorite.

7. An antimicrobial agent according to any one of claims 1 to 6, wherein the silver-chloro complex salt has the structural formula: Act_ Act_ cj3

8. A method of producing an antimicrobial agent according to any one of claims 1 to 7, which comprises mixing together an aqueous chloride solution, silver and/or a silver compound and an oxidizing agent.

9. A method of antimicrobial treatment which comprises treating a target object with an aqueous solution which contains a silver-chloro complex salt in the presence of an oxidizing agent.

15

10. A method according to claim 9, wherein the silver-chloro complex salt has the structural formula:

f LOCI- Ag- C)

11. A method according to claim 9 or claim 10, wherein the aqueous solution is an aqueous chloride solution.