Process for improving granulated detergents

Abstract

A process for improving the properties of granulated detergents, comprising adding a liquid perfume or lower alcohol to the granulated detergent produced by the spray drying method while making the detergent grains roll over, and subsequently adding thereto metallic soap powder having a mean particle diameter of less than 100.mu. when the surface of detergent grain has been imparted with a sufficient adhesive power by virtue of the adhesion of said liquid perfume or lower alcohol thereto.

Description

BACKGROUND OF THE INVENTION

a. Field of the Invention

The present invention relates to a process for improving the properties of granulated detergents produced by the conventional spray drying method so as to make them retain the excellent fluidity, hygroscopic solidification preventability and stable preservability over a long period of time and also stabilize the imparted perfume.

B. Description of the Prior Art

The majority of the prevailing granulated detergents are those manufactured by the spray drying method (that is, a method of obtaining dried grains in a short time by contacting sprayed particles of a material slurry with a hot air, which employs either the parallel-current process or the counter-current process in effecting the contact between said particles and hot air) suitable for mass production. Among these granulated detergents, the so-called detergents for domestic use are ones prepared by the spray drying method and further adding some perfume by spraying in the state of liquid thereafter. However, the thus prepared detergents for domestic use have been defective in that the fragrance is apt to diminish in a relatively short period of time and fail to last long.

Besides, though the conventional granulated detergents of the foregoing type have a satisfactory water-solubility, they are attended with troubles in respect of the hygroscopic solidification preventability thereof, entailing some trobles in respect of the stable preservability. The `hygroscopic solidification preventability` herein means the property of detergent grains to be free of solidification of absorbing moisture in the air. In other words, a granulated detergent superior in hygroscopic solidification preventability means such one as will hardly absorb or never absorb moisture in the air and will maintain a granular shape without getting solidified over a long period of time. The conventional granulated detergents are inferior in said hygroscopic solidification preventability so that hygroscopic solidification would take place even after packing thereof in a carton case. Even in the case where such solidification is somehow controlled, the fluidity of the detergent grains per se is poor, entailing in troubles on the occasion of taking out of the storing silo or packing in the carbon case.

As a measure for overcoming these defects in the prior art, the specification for U.S. Pat. No. 3,472,784, for instance, has disclosed a method of obtaining a granulated detergent by adding surface active agent and water to such inorganic builders for use in detergent as sodium tripoliphosphate, soda ash, etc. while admixing them by a ribbon mixer. And it is proposed to coat the surface of detergent grains uniformly with tripoliphosphate, soda ash or sodium sulfate. However, even these method has failed to produce a satisfactory granulated detergent as desired. Not only that, it has made no contribution to the improvement of the fragrancy required especially of the granulated detergents for domestic use in general.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a process for improving the fluidity and the hygroscopic solidification preventability of granulated detergents. Another object of the present invention is to provide a process for an everlasting stable fragrance to said granulated detergents.

In other words, the process for improving the properties of granulated detergents according to the present invention is characterized by the steps of adding a lower alcohol or liquid perfume as the binder to the surface of every grain of an ordinary granulated detergent prepared by the spray drying method while making the grain roll over, and subsequently adding thereto a specific metallic soap powder when the surface of detergent grain has been thus imparted with a sufficient adhesive power, thereby letting said metallic soap powder adhere to the surface of detergent grain.

To be more precise, the application of said lower alcohol (mainly by the spray method) to the granulated detergent is for the purpose of imparting adhesive power to the surface of detergent grain so as to facilitate satisfactory adhesion of said metallic soap powder thereto. And, the application of said liquid perfume (mainly by the spray method) to the granulated detergent is for the purpose of imparting adhesive power to the surface of detergent grain to thereby not only facilitate satisfactory adhesion of the metallic soap powder thereto but also perpetuate the fragrance of the granulated detergent. Employment of water as the binder in place of said lower alcohol or in place of said liquid perfume with a view to coating the detergent grains with metallic soap powder would fail to achieve the aimed effect because the metallic soap is poor in affinity with water so that a uniform coating of the surface of detergent grains with metallic soap powder is infeasible. And, employment of inorganic builders for use in detergent such as sodium tripoliphosphate and sodium sulfate in place of said metallic soap powder would also fail to achieve the aimed effect. There have hitherto been proposed various methods for securing the perpetuity of fragrance of granulated detergents, but none of these methods has ever adopted the rolling-granulation process applied for film coating like in the present invention and has been successful in overcoming the above-mentioned defects simultaneously.

The object of the present invention can be achieved subject to application of a lower alcohol or liquid perfume as the binder and application of metallic soap powder as the coating agent. The reason why such as effect as in the present invention can be brought about is yet to be clarified: nevertheless, it is presumed that, by virtue of synergy between the water insolubility and water repellency possessed by said metallic soap powder and the proper affinity with metallic soap possessed by said lower alcohol and liquid perfume, the metallic soap powder might uniformly adhere to the surface of detergent grains to form a coating. Particularly in the case where a liquid perfume is employed as the binder, said perfume is distributed into the inner part of the product and coated the surface so that the perpetuity of fragrance can be secured. Besides, at the time of use of the product, as a result of breakdown thereof, the fragrance becomes greater. Because of the surface of every detergent grain having been uniformly coated with metallic soap, the product granular detergent displays an improved fluidity and hygroscopic solidification preventability.

The lower alcohol applicable to the present invention is monohydric alcohol or dihydric alcohol having 1-4 carbon atoms. Such alcohols may be used either individually or upon combining two or more of them. The appropriate amount of the lower alcohol to be applied is in the range of 0.1-1 part by weight relative to 100 parts by weight of detergent grains: in case of application of less than 0.1 part by weight, the surface of detergent grain fails to get wet sufficiently, while in case of application of more than 1 part by weight, it is rather unfavorable as it will require such additional processes as drying and recovering alcohol. As to the liquid perfume for use in the present invention, any perfume commonly used in the granulated detergents for domestic use is applicable as long as it has a proper affinity with metallic soap to be coated on the layer of perfume adhering to the detergent grain, and it includes, for instance, terpene series (linalool, terpineol, geraniol) phenol series (eugenol) and aromatic alcohol series (phenylethyl alcohol, benzyl alcohol). Such liquid perfumes may be used either individually or upon combining two or more of them. The appropriate amount of the liquid perfume to be applied is in the range of 0.05-1 part by weight relative to 100 parts by weight of detergent grains.

The metallic soap powder applicable to the present invention is calcium salt or magnesium salt of saturated fatty acid having a mean particle diameter of less than 100.mu.. However, in the case where lower alcohol is employed as the binder, it is necessary to apply a fatty acid salt having 16-20 carbon atoms. Application of a metallic soap powder having a mean particle diameter of more than 100.mu. is inadvisable as it will not only necessitate the use of metallic soap powder in great quantities in order to achieve the intended effect but also spoil the appearances of the resulting product. The foregoing metallic soap powders may be used either individually or upon combining two or more of them. The appropriate amount of the metallic soap powder to be applied is in the range of 0.3-15 parts by weight -- preferably 0.5-10 parts by weight -- relative to 100 parts by weight of detergent grains: in case of application of less than 0.3 part by weight, the surface of detergent grain fails to be uniformly coated therewith, while in case of application of more than 15 parts by weight, the amount is excessive and the water-insoluble metallic soap turns into a white emulsion when the product granular detergent is dissolved in water, so that it is undesirable.

The granulated detergent constituting a material for use in the process according to the present invention suffices to be ordinary hollow grains obtained by spraying and drying a detergent composition, and is not limited to any particular detergent. In other words, the material granulated detergent consists of the surface active agent, inorganic or organic builder, fluorescent agent and other additives.

The rolling apparatus for use in the process according to the present invention is not limited to any particular one; that is, any of the well-known apparatuses can be employed. For instance, it will do employ the conventional rolling-drum for use in adding perfume in the field of detergent-manufacturing industry. Addition of the lower alcohol or liquid perfume may be performed by any method as long as uniform addition can be effected thereby; nevertheless, the spray method, and especially the nozzle-spray method employing solid cone nozzle, hollow cone nozzle and the like, are suitable. As to the method for adding the metallic soap powder, any method will do as long as uniform coating can be effected thereby; for instance, the sprinkling method may be applied.

Next, the concrete procedures for obtaining an improved granulated detergent as product according to the process of the present invention will be elucidated in the following, but it will be understood that variations and modifications thereof which lie within the scope of the invention as defined by the appended claims are fully contemplated.

To begin with, the material hollow-granular detergent is introduced into a rolling-drum. Thereafter, a prescribed amount of lower alcohol or liquid perfume is added to said granular detergent in the drum by an appropriate method, such as nozzle-spraying, while rolling the drum. When said lower alcohol or liquid perfume has sufficietly adhered to the surface of all detergent grains to make them wet, a prescribed amount of metallic soap powder is added to the thus wetted detergent grains by an appropriate method, such as sprinkling, so as to make said powder uniformly adhere to said grains. The inside temperature of the drum should of course not be so high as to permit said lower alcohol or liquid perfume to boil or evaporate. Accordingly, on the occasion of employing a granulated detergent immediately after being produced by the spray drying method as the material for use in the present invention, inasmuch the detergent grains still hold a high temperature, if said temperature is so high as to permit the lower alcohol or liquid perfume to boil or evaporate, the material granulated detergent must be once cooled.

The present invention renders it possible to achieve the desired effect by simple procedures, so that the operation can be performed continuously and is therefore suitable for mass production.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

EXAMPLE 1.

100 parts by weight of a hollow-granular detergent having the following composition as obtained by the spray drying method were introduced into a rolling-drum. 0.5 part by weight of ethanol was added to said detergent by the use of a spray nozzle at the inlet of the drum while rolling it to see that said ethanol be applied to the detergent grains uniformly. When the detergent grains were sufficiently wetted with the prescribed amount of ethanol, 1 part by weight of calcium stearate having a mean particle diameter of less than 20.mu. was sprinkled over the thus wetted detergent to make it adhere and form a coating thereon. The inside temperature of the drum on this occasion was 35.degree.C.

When the fluidity and the hygroscopic solidification preventability of the granular product thus obtained were examined after leaving said product standing for 24 hours, the results were as shown in Table-1 in the following.

Composition of the material hollow-granular detergent: sodium linear alkylbenzene sulfonate 17 g sodium tripolyphosphate 25 g sodium silicate 10 g sodium sulfate 38 g fluorescent agent 0.4 g CMC (carboxymethyl cellulose) 0.6 g water 9 g

EXAMPLE 2.

A granular detergent product was obtained through the same procedures as in Example 1 except for substituting a perfume (namely, geraniol) for ethanol. When the fluidity and the hygroscopic solidification preventability of thus product were examined, the results were as shown in Table-1 in the following. Example 3.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the following composition were coated with 2 parts by weight of calcium stearate having a mean particle diameter of less than 20.mu. by applying 1 part by weight of ethanol as the binder. The result of examination of the properties of the product was as shown in Table-1 in the following.

Composition of the material hollow-granular detergent:

sodium olefin sulfonate having 13-18 carbon atoms 17 g sodium tripoliphosphate 20 g sodium silicate 10 g sodium sulfate 43 g fluorescent agent 0.4 g CMC 0.6 g water 9 g

EXAMPLE 4.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the following composition were coated with 2 parts by weight of calcium stearate having a mean particle diameter of less than 20.mu. by applying 0.2 part by weight of a perfume (a mixture composed of geraniol and linalool at the rate of 1:1 by weight) as the binder. The result of examination of the properties of the product was as shown in Table-1 in the following.

Composition of the material hollow-granular detergent:

sodium olefin sulfonate having 15-18 carbon atoms 18 g sodium tripoliphosphate 20 g sodium silicate 10 g sodium sulfate 42 g fluorescent agent 0.4 g CMC 0.6 g water 9 g

EXAMPLE 5.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the same composition as in Example 1 were coated with 3 parts by weight of calcium stearate (consisting of 20 wt.% of particles having a mean diameter of 50-30.mu. and 80 wt.% of particles having a mean diameter of less than 30.mu.) by applying 1 part by weight of ethanol. The inside temperature of the rolling-drum on this occasion was 40.degree.C. The result of examination of the properties of the product was as shown in Table-1 in the following.

EXAMPLE 6.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the same composition as in Example 1 were coated with 1 part by weight of magnesium stearate having a mean particle diameter of less than 10.mu. instead of calcium stearate used in Example 1 and by applying 0.3 part by weight of ethylene glycol instead of 0.5 part by weight of ethanol used in Example 1. The result of examination of the properties of the product was as shown in Table-1 in the following.

EXAMPLE 7.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the following composition were coated with 2 parts by weight of calcium stearate having a mean particle diameter of less than 10.mu. by applying 0.5 part by weight of methanol as the binder. The result of examination of the properties of the product was as shown in Table-1 in the following.

Composition of the material hollow-granular detergent:

sodium linear alkylbenzene sulfonate 30 g sodium sulfate 65 g water 5 g

EXAMPLE 8.

Through the same procedures as in Example 1, 100 parts by weight of a hollow-granular detergent having the following composition were coated with 3 parts by weight of calcium stearate having a mean particle diameter of less than 20.mu. by applying 0.15 part by weight of a perfume (a mixture composed of geraniol and linalool at the rate of 1:1 by weight) as the binder. The result of examination of the properties of the product was as shown in Table-1 in the following.

Composition of the material hollow-granular detergent:

sodium linear alkylbenzene sulfonate 20 g sodium tripoliphosphate 22 g sodium silicate 10 g sodium sulfate 38 g fluorescent agent 0.4 g CMC 0.6 g water 9 g

EXAMPLE 9.

In the same way as in Example 2 except for substituting magnesium stearate for calcium stearate, a hollow-granular detergent product was obtained. The result of examination of the properties of this product was as shown in Table-1 in the following.

EXAMPLE 10.

Through the same procedures as in Example 1, 100 parts by weight of the same material hollow-granular detergent as in Example 1 were coated with 3 parts by weight of calcium stearate having a mean particle diameter of less than 20.mu. by applying 0.2 part by weight of a perfume (namely, eugenol). The result of examination of the properties of the product was as shown in Table-1 in the following.

Table 1 __________________________________________________________________________ Example No. 1 2 3 4 5 6 7 8 9 10 __________________________________________________________________________ fluid- ity* (angle of repose) 37.degree. 36.degree. 35.degree. 35.degree. 34.degree. 38.degree. 35.degree. 35.degree. 37.degree. 35.degree. hygro- scopic solidi- fica- tion pre- venta- bility** 5 5 3 4 2 6 5 3 5 5 fra- grancy*** -- 38 -- 45 -- -- -- 47 38 48 __________________________________________________________________________ Remarks: *Measurement of the fluidity was conducted by setting the temperature of the sample (product) at 35.degree.C. **The hygroscopic solidification preventability was evaluated through the procedure comprising leaving the sample standing with atmosphere of 95% i RH and 30.degree.C in 24 hrs, then sifting this sample by the use of a 4-mesh sieve, and measuring the amount of sample left on the sieve in terms of wt.%. ***The fragrancy was evaluated through the procedure comprising packing the sample in a carbon case, leaving the thus packed sample standing in a room of normal temperature upon cutting open the prescribed outlet of the carton case, and counting the number of days required for half decay of the initial fragrancy after packing.

(The above procedures for measurement and evaluation will apply to the following comparative examples too.)

Comparative Example 1.

The same material hollow-granular detergent as used in Example 1 was left standing for 24 hours without applying the treatment according to the present invention, and was thereafter subjected to examination of the fluidity and hygroscopic solidification preventability thereof. The result was as shown in Table-2 in the following.

Comparative Example 2.

In the same way as in Example 1 except for changing the amount of calcium stearate from 1 part by weight to 2 parts by weight and the particle diameter thereof to be less than 10.mu. and substituting water for ethanol, coating of the material hollow-granular detergent was effected. The result of examination of the properties of the product was as shown in Table-2 in the following.

Comparative Example 3.

In the same way as in Example 1 except for substituting sodium sulfate (applied amount: 2 parts by weight; mean particle diameter: less than 100.mu.) for calcium stearate, coating of the material hollow-granular detergent was effected. The result of examination of the properties of the product was as shown in Table-2 in the following.

Comparative Example 4.

In the same way as in Example 1 except for substituting sodium sulfate (applied amount: 2 parts by weight) for calcium stearate and 0.2 part by weight of geraniol for 0.5 part by weight of ethanol, coating of the material hollow-granular detergent was effected. The result of examination of the properties of the product was as shown in Table-2 in the following.

Comparative Example 5.

0.2 part by weight of geraniol was added to 100 parts by weight of the same material hollow-granular detergent as used in Example 1. The result of examination of the properties of the product was as shown in Table-2 in the following.

Table 2 ______________________________________ Comparative Example No. 1 2 3 4 5 ______________________________________ fluidity * (angle of repose) 42.degree. 40.degree. 38.degree. 40.degree. 42.degree. hygroscopic solidification 25 27 30 20 25 preventability ** fragrancy *** -- -- -- 32 30 ______________________________________

Claims

what is claimed is:

1. A process for improving the properties of granulated detergents, which comprises adding a lower alcohol or liquid perfume to an ordinary hollow granular detergent produced by the spray drying method when the temperature of the detergent is lower than the boiling point of the alcohol or perfume while making the detergent grains roll over, and subsequently adding thereto a powder of a water insoluble metal soap having a mean particle diameter of less than 100.mu. when the surface of the grains has been imparted with sufficient adhesive power by the addition of the alcohol or perfume.

2. A process according to claim 1, wherein said lower alcohol is at least one member selected from the group consisting of monohydric alcohols having 1-4 carbon atoms and dihydric alcohols having 2-3 carbon atoms and the amount of said lower alcohol added is in the range of 0.1-1 part by weight relative to 100 parts by weight of the detergent.

3. A process according to claim 1, wherein said liquid perfume is a member selected from the group consisting of linalool, terpinneol, geraniol, eugenol, phenylethyl alcohol, benzyl alcohol and mixtures thereof and the amount of said liquid perfume added is in the range of 0.05-1 part by weight relative to 100 parts by weight of the detergent.

4. A process according to claim 1, wherein said metallic soap is selected from the group consisting of calcium and magnesium salts of saturated fatty acids having at least 16 carbons and the amount of said metallic soap added is in the range of 0.3-15 parts by weight relative to 100 parts by weight of the detergent.