JPH03187905A - Stable granulated material of sodium percarbonate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a highly safe granulated product of sodium percarbonate (sodium carbonate hydrogen peroxide adduct). Sodium percarbonate is mainly used as an oxygen bleach for household or commercial purposes, either alone or in combination with detergents. Lithium/sulfur percarbonate itself is not flammable and is a safe compound by itself, but if it comes into contact with or mixes with flammable materials for any reason during handling or storage,
Enhanced combustion may occur under certain conditions.

The present invention relates to a granulated product of sodium percarbonate that is unlikely to cause combustion even when mixed with combustible materials, and is stable and easy to handle.

(Prior art) One way to reduce the risk of combustion when sodium percarbonate and combustible materials are mixed is to reduce the effective oxygen concentration by adding a diluent. Methods of adding agents have been tried. Examples of diluents that have been tried include sodium bicarbonate, sodium carbonate, sodium chloride, and sodium sulfate.

Generally, supercarbonate with high effective oxygen is used for convenience of use.
Therefore, it is important to provide a composition of sodium percarbonate that is highly safe against combustion, with the addition of as little as possible, ie, while maintaining as high an effective oxygen concentration as possible.

The present inventor has already discovered that sodium bicarbonate is effective as an additive that significantly increases safety when added in small amounts,
A patent application was filed for a highly safe sodium percarbonate composition made by adding sodium bicarbonate to sodium percarbonate (Japanese Patent Application No. 1-117439). Special application Hei I1
According to 17439, the safety against combustion increases as the amount of sodium bicarbonate added increases, but the effective oxygen concentration decreases, so an appropriate amount is selected from the balance between the necessary safety degree and the desired effective oxygen concentration. . Sodium bicarbonate has the same safety-improving effect as common diluents such as sodium carbonate, sodium chloride, and sodium sulfate when added in an amount of 60 to 70% by weight.

Therefore, by using sodium bicarbonate, the necessary degree of safety can be achieved while maintaining a high effective oxygen concentration.

(Problems to be Solved by the Invention) Methods for adding sodium bicarbonate include: ■ Adding sodium bicarbonate when producing sodium percarbonate by reacting IJium with an arsenic arsenic aqueous solution; ■ A method of adding wet or dry sodium percarbonate obtained by reacting an aqueous hydrogen peroxide solution with sodium carbonate during granulation: ■ Mixing it with powdered or granular sodium percarbonate obtained by drying. The following methods can be employed: (1) forming a tablet together with powdered or granular sodium percarbonate obtained by drying; and (2) coating granular sodium percarbonate obtained by drying with sodium bicarbonate.

Method (2) cannot necessarily be said to be a good method because it disturbs the reaction state depending on the amount of sodium bicarbonate added.

As an example of method (2), there are several known examples of compositions of sodium percarbonate mixed with sulfur and lithium bicarbonate together with other ingredients for use in bleaches, cleaning agents, etc. 61-36216, Japanese Patent Publication No. 54-163906
, JP 51-54111, JP 63-35200,
Special Publication No. 53-13354). In this method, since the resulting composition is a mere mixture, classification occurs during the handling process, resulting in a distribution of active oxygen content, which may reduce the effect of adding sodium bicarbonate.

As an example of method (1), a tablet is known in which the mixture is mixed with other ingredients and formed into a tablet (Japanese Patent Application Laid-Open No. 63-23812). However, tablets have a special shape, and because of their large size, they have the disadvantage that they cannot be mixed and dispersed sufficiently when blended with other ingredients, and also have low productivity and high costs.

As an example of method (1), sodium percarbonate coated with other ingredients and sodium bicarbonate is known (Japanese Patent Publication No. 5B).
-243'61). In this method, the sodium bicarbonate and sodium percarbonate are not uniformly mixed and dispersed, resulting in weak particle strength. It is difficult and expensive to add large amounts of sodium bicarbonate, making it uneconomical.

The addition granulation method (2) is the most preferable method because it is economically superior because sodium bicarbonate is uniformly dispersed and mixed in all the particles, so there is no risk of classification, and there is no complication in the process. As an example of method (2), a method of granulating with sodium bicarbonate together with other ingredients is known (Japanese Patent Publication No. 5O-27824), but this method uses α starch or carboxymethyl scouch in combination with an alcohol aqueous solution to form granules. This is a method of In this method, alcohol is used as a solvent in addition to the water plate, which complicates the process and increases costs. As another example of method (2), it has been proposed to use sodium bicarbonate as another diluent in a composition of 1-lium percarbonate containing sodium chloride or/and sodium sulfate (Japanese Patent Application Laid-open No. 58-204806), but this method contains sodium chloride and/or sodium sulfate as essential components, and this method is not effective in making it safe while maintaining a high active oxygen content.

The method of adding sodium bicarbonate when granulating wet or dry sodium percarbonate obtained by reacting an aqueous hydrogen peroxide solution with sodium carbonate is a safe way to granulate sodium percarbonate. Although this is an excellent method for producing a product, the sodium percarbonate granules obtained in this way are more stable during storage than sodium percarbonate that does not contain 1-lium bicarbonate as a diluent. This has the drawbacks of lower properties and lower particle strength.

Sodium percarbonate and its granules tend to gradually decompose and lose active oxygen during storage.

It is prone to decomposition, especially at high temperatures or in humid atmospheres. This decomposition causes the sodium percarbonate granules to lose their available oxygen during storage or transportation, reducing their potency before use. Therefore, it is desired to be as stable as possible.

Sodium percarbonate granules containing sodium bicarbonate have a disadvantage in that they have lower stability during storage, particularly in a humid atmosphere, than sodium percarbonate that does not contain sodium bicarbonate.

Furthermore, it is desirable for the particles to have high physical strength since it is difficult to handle the particles by crushing them to generate fine powder during transportation during the manufacturing process, transportation to the market, or during use. Sodium percarbonate granules containing sodium bicarbonate have a disadvantage in that their particle strength is lower than that of sodium percarbonate that does not contain bicarbonate.

Although various stabilizers or granulation binders for sodium percarbonate are known, no sodium percarbonate granules containing sodium bicarbonate are known other than the above-mentioned examples.

(Means for Solving the Problems) As a result of intensive study to solve the above-mentioned problems of sodium percarbonate granules containing sodium bicarbonate, the present inventor added silicon oxide or silicate. The present invention was completed based on the discovery that sodium percarbonate granules containing sodium bicarbonate can be produced by this method without impairing stability or particle strength.

Specifically, the present invention relates to sodium percarbonate granules containing sodium bicarbonate and containing silicon oxide or silicate. The present invention also relates to a method for producing granulated sodium percarbonate, which comprises adding silicon oxide or silicate when granulating sodium bicarbonate and sodium percarbonate.

The sodium percarbonate to which sodium bicarbonate is added may be sodium percarbonate as a dried product;
As mentioned above, when granulating wet or dry sodium percarbonate obtained by reacting an aqueous hydrogen peroxide solution and sodium carbonate, the method of adding bicarbonate (bicarbonate) was considered to be economical. Sometimes it's reasonable.

Any method may be used to add silicon oxide or silicate as long as it can be added together, but it is preferable that silicon oxide or silicate be dispersed and mixed as uniformly as possible with sodium percarbonate and sodium bicarbonate. In this respect, it is preferable to add silicon oxide or silicate together when adding sodium bicarbonate and granulating.

The amount of sodium bicarbonate added is usually 3 to 50% by weight, preferably 5 to 50% by weight, more preferably 7 to 30% by weight, and most preferably 7 to 20% by weight based on sodium percarbonate.
Weight%. If the amount of sulphurium bicarbonate exceeds 50% by weight, the stability during storage tends to decrease and the particle strength tends to decrease. Moreover, if it is less than 3% by weight, sufficient safety cannot be ensured. Sodium bicarbonate is effective when used alone as a diluent, but it is also effective when used with other diluents such as sodium carbonate, sodium chloride, sodium sulfate, and sodium borate.

Sodium bicarbonate may be added in the form of a powder, an aqueous solution, or a mixture of the two, but it is convenient to add it in the form of a powder.

Any silicon oxide or silicate that can be used in the present invention is effective, but examples include (1)
) silicon oxide such as colloidal silica and white carbon, (2) sodium orthosilicate, sodium metasilicate,
Water Glass No. 1, Water Glass No. 2, Water Glass No. 3, sodium silicate such as powdered sulfur and lithium silicate, and alkali metal silicate such as lithium silicate, potassium silicate, rubidium silicate, cesium silicate, (3) calcium silicate Alkaline earth metal silicates such as , magnesium silicate, and barium silicate are effective. Among these, colloidal silica and alkali metal salts of silicic acid such as No. 1, No. 2, and No. 3 water glass, sodium oleate, sodium metasilicate, lithium silicate, and potassium silicate are particularly preferred, and colloidal silica and sodium silicate are economical. It is most preferable when considering the following. These may be used alone or in combination of two or more. It may also be used in combination with other known binders and stabilizers.

The silicon oxide or silicate may be in any form, but in the case of a solid, it is preferable that the particles be small so that they can be dispersed well. In this respect, in the case of silicon oxide, it is a preferable method to add a colloidally dispersed solid to an aqueous medium, as in the case of colloidal silica. In the case of silicates, in addition to adding them in the form of powder, it is preferable to add them in the form of an aqueous solution, as in the case of water glass.

The amount of silicon oxide or silicate added is silicon oxide (SiO□)
0.01 to 10% by weight, preferably 0.05 to 7% by weight, more preferably 0.07 to 5% by weight, most preferably 0.1 to 3% by weight, based on sodium percarbonate.
It is. If the amount of silicon oxide or silicate added is less than 0.01% by weight, the stabilizing effect and the effect of increasing the physical strength of the granules will not be sufficient, and if it exceeds 10% by weight, the effective oxygen content of the sodium percarbonate granules will be reduced. This is not preferable because it unnecessarily lowers the water content and the solubility of the granulated material in water becomes worse.

Sodium percarbonate granules are used as bleach cleaning agents by combining them with surfactants and inorganic or organic auxiliaries, but even in this case, the effect of adding sodium bicarbonate is not impaired, and it is safe in small amounts. The trend toward increased sexual orientation is maintained. Furthermore, the stabilizing effect of silicon oxide or silicate is retained.

Examples of surfactants that can be blended with sodium bicarbonate and sodium percarbonate granules containing silicon oxide or silicate include (1) sodium laurate, sodium stearate, sodium myristate, sodium palmitate, Fatty acid salts such as sodium oleate, sodium linoleate, sodium linoleate, sodium lysylsinate, (2) ortho, meta,
Sodium salt of alkylbenzene sulfonic acid in para position,
Salts such as ammonium salts and alkylolamine salts, (3
) Higher alcohol sulfate ester salts such as lauryl alcohol sulfate sodium salt and oleyl alcohol sulfate ester sodium salt, (4) cationic surfactants such as tetraalkyl quaternary ammonium salts, (5)
Examples include, but are not limited to, nonionic surfactants such as polyoxyethylene adducts of alkylphenols or higher alcohols, alkylolamides of fatty acids, and (6) amphoteric surfactants such as dodecyldiaminoethylglycine hydrochloride. It is not applicable to surfactants that can be used as bleach cleaning agents.2 The following are examples of auxiliaries that can be blended with sodium bicarbonate and sodium percarbonate granules containing silicon oxide or silicate. Examples include inorganic auxiliaries such as carbonates, bicarbonates, silicates, phosphates, sulfates, thiosulfates, hyposulfites, sodium hydroxide, and organic auxiliaries such as carboxymethylcellulose and ethylenediaminetetraacetate. However, the present invention is not limited to these, and can be applied to inorganic or organic auxiliaries that can be used in bleach cleaning agents.

In addition to the above-mentioned surfactants and auxiliaries, bleaching detergents contain enzymes and those disclosed in JP-A-57-73100 and JP-A-59-1293.
Enzyme deactivation inhibitors as disclosed in Publication No. 00,
In particular, the hexagonal crystal system of anhydrous calcium sulfate, calcium sulfate 1/2 hydrate, etc.
Fragrances as disclosed in Publication No. 1983, 14
Coloring agents such as ultramarine as described in Publication No. 38,
Furthermore, various trace additives such as silicones, bactericides, antioxidants, optical brighteners, and ultraviolet absorbers may be added, but even when these are added, sodium bicarbonate is added. The trend towards improved safety will be maintained. Furthermore, the stabilizing effect of silicon oxide or sodium silicate is retained.

As the granulation method in the present invention, a conventional powder granulation method can be adopted. Examples include transfer granulation, extrusion granulation, fluidized granulation, mixed granulation, disintegration granulation, spray drying granulation, and the like.

Particularly preferred granulation methods include a method in which extrusion granulation is performed after mixing or kneading, or a method in which granulation is performed by kneading and then crushing. Methods belonging to the latter include JP-A-57-71631 and JP-A-5.
The methods disclosed in JP-A-8-20228, JP-A-58-49605, and JP-A-58-49606 are exemplified. By employing these methods, sodium bicarbonate and silicic acid or silicate can be uniformly dispersed, and the intended purpose of increasing storage stability and particle strength can be achieved effectively and economically. I can do it.

There is no particular restriction on the size of the particles of the granulated product, but from the viewpoint of convenience in transportation, transportation, etc., the particle size is preferably in the range of 100μ to 2000μ, with a median diameter of 200μ to 12μ.
Something around 00μ is easy to handle.

(Function) In the present invention, sodium bicarbonate is used as a kind of diluent to inhibit combustion, thereby increasing safety when sodium percarbonate is mixed with combustible materials, and silicon oxide or silicate is used as a kind of binder. It acts as a type of stabilizer, and when sodium bicarbonate is added, it has the effect of stabilizing sodium percarbonate and increasing the physical strength of the granules.

(Effects of the Invention) According to the present invention, it is possible to provide sodium percarbonate granules that are highly safe against combustion, have excellent storage stability, and have high particle strength while maintaining a high effective oxygen concentration. can.

(Example) Next, the present invention will be described in more detail with reference examples, examples, and comparative examples. % in the examples means % by weight unless otherwise specified.

Reference Example (Production Example of Sodium Percarbonate) In a stainless steel reactor equipped with a stirrer, a thermometer, and a cooling jacket, 30 liters of a reaction mother liquor containing 2% H20□ and 12% Na2G03 is prepared. 15~
60%11 while stirring while maintaining the temperature at 20°C.
□02 2.5kg', Na2C○3 3. At the same time, Okg was gradually added over about 1 hour, and the added acid was stirred for an additional 1 hour while maintaining the above temperature. The resulting slurry was separated into sodium percarbonate crystals and a filtrate using a centrifuge to obtain about 3.5 kg of wet sodium percarbonate.

Examples 1 to 6 Wet sodium percarbonate powder obtained by the method of the reference example was supplied to Nigu, and a predetermined amount of 1 to 6 parts sodium bicarbonate to 6 parts sodium percarbonate (dry standard) was added thereto. Then, 5 iOz of colloidal silica (Snowtex manufactured by Nissan Chemical; 5i02 20% aqueous solution) was added in an amount of 0.5% based on sodium percarbonate (dry basis), and the total water content was further adjusted to 10 to 15%. A desired amount of water was added to the mixture, and the mixture was kneaded for 30 minutes. The kneaded wet rings are extruded and granulated using a granulator, and the granules are dried using a fluidized fluid dryer to obtain a median particle diameter of 300μ to 600μ.
A product of μ was obtained. A combustion test, storage stability test, and particle strength determination test were conducted on this product as follows.

(Combustion test) The sample and wood flour were mixed at a weight ratio of 7:3, the total of both was 40 g, and the ratio of height to bottom diameter was 1:1.
5 conical deposits were made.

A circular nichrome wire heated to about 1000° C. was brought into contact with the base of the deposit for 10 seconds. Table 1 shows the results of observing the combustion situation.

The symbols in the table mean the following situations.

◎: Does not ignite.

○: Flame ignited and extinguished halfway.

◇: After flaming, the process progresses to smoke burning, but the smoking time is longer than the flaming time.

△: After flaming, the process progresses to smoke burning, but the flaming time is longer than the smoking time.

(Storage stability test) Crystallizer containing 1 g of sample (inner diameter 26 mm, height 30 mm)
) in a desiccator filled with water and kept at 45°C for 24 hours. After standing, the sample is titrated with N/4KM n O4 to determine the active oxygen content. The active oxygen loss rate was determined using the following formula.

Active oxygen loss rate (%) - (I The results are shown in Table 2.

(Particle strength determination test) Particle strength was determined by measuring the crushing rate using an apparatus as shown in FIG. 1 of the attached drawings. In this apparatus, 1 is a sample supply tube, 2 is a bent glass tube with an inner diameter of 8 mm and has 14 acute bends, and 4 is a sample collection tube. The sample supply tube 1 is connected to the flex tube 2 by a conduit 7 provided with a cock 5, one end of which is connected to a conduit 8 attached to the sample collection tube 4. The other end of the bent tube 2 has an air inlet hole 3. The conduit 8 is equipped with a conduit, and the bent pipe 2 is connected to the upper part of the conduit. The crushing rate was measured as follows. After sieving 100 g of the sample through a 32-mesh sieve and measuring the weight of the sample on the sieve, the upper and lower sides of the sieve are mixed and supplied to the sample supply tube 1. Next, air inlet hole 3
Air is introduced at a speed of 14111/sec from conduit 7.
The cock 5 is opened, and the sample in the supply tube 1 is force-fed and collected in the sample collection tube 4. Once the sample has been collected, open the container and collect it. This operation is repeated five times for the same sample, the collected sample is sieved again, and the weight remaining on the sieve is measured. The crushing rate was calculated using the following formula.

9 Crushing rate (%) - (1 Examples 7 to 9 The product obtained in Example 4 and a surfactant were mixed in a predetermined ratio in a blender. A combustion test was conducted on this mixture. The combustion situation was It is shown in Table 1.

Examples 10-14 Products were obtained in the same manner as in Examples 1-6 by adding 15% sodium bicarbonate and adding a predetermined amount of silicate. Storage stability tests and particle strength measurements were conducted on this product. The results are shown in Table 4.

Examples 15-17 The wet sodium percarbonate powder obtained by the method of the reference example was dried in a fluidized fluid dryer to obtain sodium percarbonate.

To this was added 105% sodium bicarbonate powder, a predetermined amount of silicon oxide or silicate, and further added a desired amount of water so that the water content was 10 to 15%, and kneaded for 30 minutes. The kneaded wet mass was granulated using an extrusion granulator, and the granules were dried using a fluidized fluid dryer to obtain a product. Storage stability tests and particle strength measurements were conducted on this product. The results are shown in Table 5.

Comparative Examples 1-6 Examples 1-6 except that no colloidal silica was added
Products were obtained in the same manner as above. Storage stability and particle strength of this product were measured. The results are shown in Table 3.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for a particle strength determination test. 1...Sample supply tube 2...Bent pipe 4...Sample collection tube

Claims (2)

[Claims] (1) 3 parts sodium bicarbonate to 3 parts sodium percarbonate
Contains ~50% by weight, and silicon oxide or silicate in terms of SiO_2 relative to sodium percarbonate is 0.01~10
Sodium percarbonate granules containing % by weight. (2) The method for producing sodium percarbonate granules according to claim 1, characterized in that silicon oxide or silicate is added when granulating sodium bicarbonate and sodium percarbonate.