JPH06157010A - Stabilized sodium percarbonate composition and its production - Google Patents

Abstract

PURPOSE:To improve the preservation stability of sodium percarbonate by adding a stabilizer containing starch or/and its derivative to sodium percarbonate, granulating the resultant mixture and further coating the granulated mixture with another inorganic and/or organic substance. CONSTITUTION:Starch or dextrin is preferred as starch or its derivative. The amount thereof added is preferably 1-20%. Various cross-linking agents (e.g. melamine) for cross-linking starch molecules are effectively added so as to enhance the water resistance of the starch and improving the stability thereof. Furthermore, a usually used magnesium salt or other stabilizers in combination can be employed without any problem at all. When the starch is used, it is introduced into warm water at 40-90 deg.C, sufficiently mixed and dissolved and a required amount of water is then supplied. Sodium percarbonate is subsequently added and the obtained mixture is granulated and dried. An aqueous solution of an organic coating agent (e.g. polyethylene glycol) or an inorganic coating agent (e.g. sodium carbonate) is then sprayed on the surface thereof and dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sodium percarbonate having excellent storage stability and a method for producing the same.

[0002]

2. Description of the Prior Art The present invention is
The present invention relates to sodium percarbonate having excellent storage stability.
Sodium percarbonate is a typical bleach along with sodium perborate. Although the bleaching effect is slightly inferior to chlorine-based bleaching agents, its bleaching effect is mild and damages the fabric even for synthetic fibers, animal and plant fibers, and even dyed fibers,
It is very useful as a bleaching agent for household and business use because it has no discoloration. Among them, the main purpose of using the bleaching agent for home use is to bleaching at the time of washing, and the bleaching effect is synergistically increased by mixing with a general detergent.

However, sodium percarbonate has poor storage stability and has a drawback in that effective oxygen is rapidly lost during storage due to the influence of moisture in the air. Furthermore, many of the zeolites greatly accelerate the decomposition of this sodium percarbonate. Zeolite is usually incorporated into household detergents as a builder for softening hard water, and when this detergent and sodium percarbonate are incorporated, it loses available oxygen very quickly and loses its function as a bleaching agent. Therefore, the sodium percarbonate is not usually mixed into household detergents, and it is necessary to separately add the detergent and the sodium percarbonate at the time of washing.

To improve the above-mentioned drawbacks, impurities in the sodium percarbonate production raw material are generally reduced. Add hydrogen peroxide stabilizer. Sodium percarbonate is coated with organic and inorganic substances. Etc. have been studied.

Of these methods, the first method is E
It is a method of producing sodium percarbonate using sodium carbonate in which metal ions are blocked by a chelating agent such as DTA or NTA. The method (2) is a method for obtaining sodium percarbonate in which hydrogen peroxide is stabilized with phosphate, silicate or the like. The above method is merely a method for stabilizing sodium percarbonate, and there is no problem when using sodium percarbonate alone, but there is almost no stabilizing effect when compounded with zeolite. Is a method of coating sodium percarbonate with paraffin or borate, etc., and although the stability is good, the former is not soluble in water, so sodium percarbonate does not dissolve in water when used in water. It does not dissolve and is not practical.
The latter is soluble in water, but its stability to zeolite is insufficient and the stability when mixed with a detergent is not satisfactory.

The performance required for the sodium percarbonate to be mixed with the detergent in this manner is that it is highly stable in the detergent and that it dissolves quickly in water.

[0007]

DISCLOSURE OF THE INVENTION In view of the above-mentioned drawbacks, the present inventors have made various studies and found that after adding and granulating a specific stabilizer to sodium percarbonate to make it into a granular form, the
In addition, they have found a method for producing sodium percarbonate which is stable to household detergents or zeolite used in detergents and has good water solubility by coating with an organic substance.

That is, according to the present invention, a stable sodium percarbonate composition characterized by containing starch or / and a starch derivative and a stabilizer containing starch or / and a starch derivative are added and granulated to give a granular form. It is intended to provide a method for producing sodium percarbonate, which comprises coating the sodium percarbonate with another inorganic substance and / or organic substance.

Usually, the purpose of coating the sodium percarbonate is to prevent contact with moisture in the air or zeolite by the coating and to stabilize the sodium percarbonate. Water-insoluble materials such as small paraffins are preferable, and in fact when paraffin is used for coating, it is possible to obtain sodium percarbonate that is extremely stable against moisture and zeolite. However, since paraffin has no solubility in water, sodium percarbonate is hardly dissolved even if it is thrown into water. On the other hand, when the coating is performed using a water-soluble material such as a water-soluble polymer material that places importance on the solubility in water, the solubility of sodium percarbonate is good, but the polymer material itself is Permeate or adsorb, and impair the stability of sodium percarbonate.

As a result of various studies, the inventors of the present invention added starch or its derivative as a water-soluble material and granulated it to cover the crystal particles inside the granular sodium percarbonate, which was extremely effective for detergents. It became stable and reached the present invention. More effectively, it was also possible to make the sodium percarbonate more stable to detergents by further coating the organic or inorganic substance on the sodium percarbonate in which the starch or starch derivative was added and granulated.

The present invention will be described in detail below. With respect to the starch or starch derivative used in the present invention, starch and dextrin obtained by solubilizing the starch molecular chain are suitable. Further, the addition amount is preferably 1 to 20% because the effect is small when the addition amount is small, and the effective oxygen content of sodium percarbonate decreases when the addition amount is large.
It is also effective to add various cross-linking agents for cross-linking starch molecules, such as melamine, in order to increase the water resistance of the starch and improve its stability. Furthermore, the combined use of normally used magnesium salts and other stabilizers can be used without any problems. When starch is used, the starch is added to warm water at 40 to 90 ° C., mixed and dissolved well, then a necessary amount of water is replenished, added to sodium percarbonate, granulated and dried. Granulation and drying may be carried out by a method usually used in the case of sodium percarbonate.

Next, in order to further enhance the effect of starch, the results obtained by adding starch and granulating the surface of granular sodium percarbonate with an organic or inorganic coating agent can be obtained. Polyethylene glycol, starch, and the like, which are commonly used as organic coating agents, and commonly used coating agents, such as sodium carbonate, baking soda, and boric acid, may be used as inorganic coating agents. That is, the method of spraying an aqueous solution of the coating agent while heating the sodium percarbonate in a fluidized bed and drying is effective.

[0013]

EXAMPLES The effects of the present invention will be described below with reference to examples. Example 1 15 g of starch and 38 g of dextrin were put in 110 g of hot water at 70 ° C. and stirred and dissolved for 5 minutes. Separately, 600 g of sodium percarbonate powder and 1.2 g of magnesium sulfate are mixed well. A starch-dextrin solution was added to the sodium percarbonate powder and mixed for 10 minutes, then granulated using a twin-screw extrusion granulator (manufactured by Fuji Paudal Co., Ltd.) and dried using a fluid bed dryer. did. The stability of the obtained granular sodium percarbonate using a commercially available zeolite for detergent and a detergent was measured by the following method. The measurement results are shown in Table 1.

[Detergent Stability Measuring Method] Synthetic Zeolite 2
90% of linear sodium alkylbenzene sulfonate-based heavy detergent containing 0% and 2% of water (commercially available product) was mixed with 10% of the obtained granular sodium percarbonate, and the temperature and humidity were kept at 40 ° C and 80% RH. It is left in the tank for 2 weeks and the residual ratio of available oxygen is measured to determine the stability against detergent.

[0015]

[Table 1]

Example 2 Granules were prepared in the same manner as in Example 1 except that 0.5 g of melamine was added to the starch-dextrin solution prepared by the method of Example 1 as a cross-linking agent for further improving the water resistance of starch. Sodium percarbonate was produced and stability was measured.

Example 3 500 g of granular sodium percarbonate produced by the method of Example 2
While maintaining at 60 ° C. in a heated fluidized bed, 75 g of a coating agent of the starch, dextrin, and melamine aqueous solution produced by the method of Example 2 was sprayed for coating. The stability of the obtained coated sodium percarbonate was measured by the method of Example 1.

Example 4 500 g of granular sodium percarbonate prepared by the method of Example 2
While maintaining at 60 ° C. in a heating fluidized bed, 260 g of a 10 wt% boric acid aqueous solution at 50 ° C. was sprayed and coated with boric acid. The stability of the obtained coated sodium percarbonate was measured by the method of Example 1.

Comparative Example 1 600 g of sodium percarbonate powder and 1.2 g of magnesium sulfate
Mix well, add ion-exchanged water to add water for 10 to 15
%, Twin-screw extrusion granulator (Fuji Paudal Co., Ltd.)
Manufactured by K.K.) and dried using a fluidized bed drier. 500 g of this granular sodium percarbonate was heated at 60 ° C. in a fluidized bed.
10% by weight boric acid aqueous solution at 50 ° C
It was sprayed with 0 g and coated with boric acid. The stability of the obtained coated sodium percarbonate was measured by the method of Example 1.

[0020]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a sodium percarbonate having excellent storage stability, particularly sodium percarbonate which is stable against zeolite used in detergents.

Front page continuation (72) Inventor Motonao Yamamoto 5253 Oki Ube, Ube City, Yamaguchi Prefecture Central Rural Co., Ltd. Ube Laboratory

Claims (2)

[Claims] 1. Stabilized sodium percarbonate composition, characterized in that it comprises starch or / and starch derivatives. 2. A sodium percarbonate characterized by comprising adding and granulating a stabilizer containing starch or / and a starch derivative, and further coating the granulated sodium percarbonate with another inorganic substance and / or organic substance. Production method.