Odor-Removing and Deodorizing Composition Employing a Hydrolysate of Keratin Material

1. Field of the Invention

This invention relates to an odor-removing and deodorizing composition and more particularly, to a composition of the just-mentioned type comprising hydrolysates of keratin materials.

2. Description of the Prior Art

Offensive odors emitted from refuse boxes, water closets and the like involved in places of human activity such as, for example, ordinary homes, business facilities and public service and particularly those of mercaptan, hydrogen sulfide and the like which have been considered difficult in removing their odors are highly desired to be advantageously removed or masked and deodorized. Also during the course of permanent waving, there is generated a bad smell such as of mercaptan ascribed to the decomposition of thioglycol contained in chemicals and keratin in the hair on the way of the treatment, often causing one to feel objectionably.

A number of methods of removing the offensive odor or smell have heretofore been proposed and may broadly be classified into four categories including an odor-removing neutralization method, an odor-removing adsorption method, an odor-removing masking method and an odor-removing biochemical method. However, these methods have all the following disadvantages and are not necessarily satisfactory.

This is a method of neutralizing acidic or basic materials giving off bad odor by application with basic or acidic odor-removing bases. This method is effective for local removal of odor but has the disadvantage, when the odor over a wide sphere is removed, that a large quantity of odor-removing bases is required and the efficacy of bases does not develop unless excess neutralization is effected, thus this method being not practically useful in most cases. Moreover, the vital drawback of the method is that neutral offensive odors, e.g. a putrid smell ascribed to mercaptan, cannot be removed.

This is a method of adsorbing offensive odors on porous materials such as active carbon but has the disadvantages that the diffusion of offensive odors into adsorbents is rate-limiting and the adsorbent does not have effect on removal of odor over a wide area, that it takes long time before an adsorption equilibrium is reached and it is not necessarily easy for the equilibrium system to lower the concentration below a threshold value of offensive odor, and that adsorbents do not show activity with respect to all the types of offensive odors.

This is a method of merely masking offensive odors with perfumes and thus the origin of offensive odor is not removed substantially, so that this method is not a substantial odor-removing method.

This is a method of preventing emission of bad smells by lowering the activity of microorganisms with use of bacteriostatics or bactericides, but the method is preventive and does not give any effect on once emitted offensive odors.

As having described above, the currently employed odor-removing methods are not satisfactory for all origins of offensive odors and particulary for mercaptan and hydrogen sulfide. In this connection, there have recently been reported deodorizing bases which are effective for mercaptan and hydrogen sulfide but almost all of these bases are highly stimulative against mucous membranes such as of eyes, nose, throat and the like and cannot be applied actually.

Under these circumstances, the present invention have made a study to find out odor-removing bases which effectively act on mercaptan and hydrogen sulfide with which it has been considered difficult to remove their odors or deodorize and which show little mucous stimulativeness and found that hydrolysates of keratin materials satisfy the above requirement.

That is, the present invention provides a novel odor-removing and deodorizing composition which comprises as its effective component a hydrolysate of keratin material.

The hydrolysates of keratin material (hereinafter referred to as "keratin hydrolysate(s)) used in the present invention are obtained by hydrolyzing keratin materials.

The starting keratin materials are, for example, animal hairs, human hair, feathers, nails, horns, hooves, scales and the like, among which wool, human hair and feathers are most preferable. These keratin materials may be subjected to the oxidation or reduction reaction as they are, or may be cut or reduced into pieces or may be subjected to pretreatments such as washing and defatting as desired.

The hydrolysis of keratin material may be effected by any known methods without limitation. Examples of the methods are as follows.

Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, hydrobromic acid and the like, and organic acids such as acetic acid, formic acid, oxalic acid and the like.

The hydrolysates obtained by the acid hydrolysis do not undergo any changes other than hydrolysis at polypeptide chains of keratin, so that better results are obtained than in the case of hydrolysis with alkali.

Examples of alkalis include inorganic alkalis such as sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, sodium silicate, borax and the like.

Examples of enzymes include acidic proteinases such as pepsin, protease A, protease B and the like, and neutral proteinases such as papain, promeline, thermolycin, trypsin, pronase, chymotrypsin and the like.

The hydrolysates obtained by these hydrolysis reactions should preferable have an average molecular weight of from 200 to 5,000. The disulfide bonds in the keratin hydrolysates should favorably be left in amounts as great as possible. To this end, it is recommended to use a keratin material of high purity and to effect the hydrolysis under mild conditions.

The odor-removing and deodorizing composition according to the present invention can be used in any known forms by treating the keratin hydrolysate to be an odor-removing base by usual manners, including liquids obtained by dissolving the hydrolysate in solvents or emulsifying it using surface active agents; aerosols obtained by filling the liquids in a spray container along with an injector; gel-like solids mixed with natural or synthetic gel bases such as agar-agar, carrageenan, polyethylene glycol and the like; solids in which the hydrolysate is absorbed in paper or porous materials or is incorporated in synthetic resins such as polyethylene; and powders in which the hydrolysate is admixed with powdery, inorganic materials such as silica, perlite and the like.

If necessary, solvents, surface active agents, acidic materials such as hydrochloric acid, phosphoric acid, citric acid, malic acid, tartaric acid and the like, alkaline materials such as sodium hydroxide, triethanolamine, basic amino acids and the like, bactericides, perfumes; colorants and the like may be further added to the composition of the invention.

In the production of the odor-removing and deodorizing agents, there are used as a solvent alcohols or glycols such as ethanol, isopropanol, propylene glycol, polyethylene glycol, diethylene glycol, triethylene glycol and the like, or deionized water. Examples of the surface active agents include anionic active agents such as higher alcohol sulfates, alkylarylsulfonates, soaps of fatty acids or resin acids, polyoxyethylenealkyl or alkylphenyl ether sulfates, alkylsulfosuccinates, alkylsulfonates, .alpha.-olefinsulfonates and the like, nonionic active agents such as polyoxyethylenealkyl phenyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene stearate, glycerol fatty acid esters, ethylene oxide adducts or castor oil or lanolin and the like, and anionic and amphoteric active agents such as quaternary ammonium salts, higher alcohol betaine and the like. Examples of the bactericides (antiseptics) include parahydroxyalkyl benzoates (parabens), sorbic acid or its potassium salt, dehydroacetic acid or its sodium salt, sodium propionate, and anionic and amphoteric active agents.

The amount of the odor-removing and deodorizing composition of the invention varies depending on the intensity and type of offensive odor and is determined so that the concentration of the keratin hydrolysate is generally in the range of over 0.01 wt% (hereinafter referred to simply as %), inclusive, preferably over 0.1%, of the system to be treated. Accordingly, the amount of the keratin hydrolysate in the odor-removing and deodorizing composition is in the range of 0.1-10%, preferably 0.5-5%.

The odor-removing and deodorizing composition of the invention can be used over a wide range of pH by adjusting with acidic or alkaline materials to a pH of 0.5-10, preferably 1-8. Accordingly, when the composition is adjusted in pH to an acidic range of, for example, 1-3, it is possible to remove not only offensive odors of mercaptan and hydrogen sulfide but also the odor of ammonia.

The present invention is described by way of references and examples, which should not be construed as limiting the present invention thereto.

(a) 10 g of wool fibers were immersed in 300 g of a 75% phophoric acid aqueous solution and hydrolyzed at a temperature of 120.degree.-130.degree. C. for 5 hours. The reaction solution was cooled and filtered to remove insoluble matters therefrom, after which 4-5 times by volume of water was added and insoluble matters were further removed by centrifugation. Then, calcium carbonate or barium hydroxide was added to adjust the pH to 6.7, followed by collecting the resulting precipitate by filtration and drying to obtain 8.0 g of a hydrolysate with a molecular weight of 1,500.

(b) 100 g of feathers were heated in an autoclave by means of a superheated steam of 6 kg/cm.sup.2 and 240.degree. C. for 6 minutes and released abruptly into the air to obtain a porous puffed product. This puffed product was reduced into pieces and admixed with 3 liters of 0.3N caustic soda, followed by hydrolysis at 60.degree. C. for 18 hours, neutralizing with 1N hydrochloric acid and filtering the reaction solution. The resulting filtrate was subjected to the ultrafiltration using a membrane with a fractional molecular weight of 500 to remove sodium chloride therefrom, with the aqueous solution of the keratin hydrolysate being concentrated, followed by freeze drying to obtain 7.2 g of the keratin hydrolysate. The molecular weight of the hydrolysate determined by the gel filtration technique was 1,800.

An odor-removing and deodorizing composition of the following composition was prepared and its odor-removing effect was examined.

The odor-removing effect was determined as follows. That is, 0.05 ml of a methyl mercaptan standard solution* was placed in a 100 ml Erlenmeyer flask as an offensive odor source, into which was immediately dropped 0.5 ml of the composition, followed by tightly sealing and keeping at 20.degree. C. for 5 minutes. Then, the concentration of the methyl mercaptan was measured by the Kitagawa detector tube and after standing for 5 minutes, the odor in the flask was evaluated by 5 panel members.

Methyl mercaptan standard solution for testing bad smell substances (Wako Junyaku Ind. Co., Ltd: content 1 .mu.g/1 .mu.l (benzene solution))

Composition:

Results:

An odor-removing and deodorizing composition of the formulation indicated in Table 2 was prepared and sprayed for 5 seconds in a one liter beaker in which had been placed 1 ml of mercaptoethanol and 96 ml of purified water to examine its odor-removing effect. The effect was judged by organoleptically evaluating odors in the beaker by 5 panel members 3 minutes after the spraying.

An odor-removing and deodorizing composition of the formulation indicated in Table 3 for use in permanent wave treatment was prepared and its effect was examined. The results are shown in Table 4.

Composition:

Test method:

4 tresses of human hairs each having a weight of 10 g and a length of 20 cm were each immersed in 100 ml of first agent for permanent wave (waving lotion) for 15 minutes to conduct the perm treatment. Thereafter, the four tresses were removed, lightly squeezed and applied with 5 ml of the odor-removing and deodorizing composition, followed by organoleptically evaluating the effect by 10 panel members.

For control, the treated tress was washed with running water for 10 seconds without use of any odor-removing and deodorizing composition and its effect was also judged.

Results:

An odor-removing and deodorizing composition of the formulation indicated in Table 5 for use in permanent wave treatment was prepared and three females with a hair length of about 20 cm as subjects were each actually permanent waved. The odor-removing and deodorizing effect on the emitted offensive odors was evaluated. The results are shown in Table 6.

Composition:

Test Method:

The hair wound about a rod was applied with 80 ml of a commercially available the first agent for permanent wave (waving lotion) containing as its chief component ammonium thioglycollate and allowed to stand for 15 minutes.

Then,

(1) Subject A was washed with running water for 1 minute,

(2) Subject B was applied with 30 g of the present composition indicated in Table 5, and

(3) Subject C was applied with 30 g of the comparative product indicated in Table 5.

The odors of the respective hairs were evaluated by 5 panel members.

Thereafter, 100 ml of a second agent for the permanent wave (neutralizer) was applied to each of the hairs, which was allowed to stand for 15 minutes, and washed with water for 2 minutes, followed by evaluation by the expert panel.

Results: