JPS6251882B2 - - Google Patents

Description

[Detailed description of the invention] The present invention provides a hollow granular and stabilized sodium carbonate hydrogen peroxide adduct (2Na ₂ CO ₃ 3H ₂ O ₂ or less).
It is abbreviated as PC. ).

PC is commonly used as an oxygen-based bleaching agent for home and commercial use, either alone or in combination with detergents.

There are various reports regarding PC manufacturing methods, but
Regarding the properties required for a product, first of all, considering stability and fluidity, dense and large particles are good, but they have poor water solubility and have a high bulk specific gravity, so when blended into a detergent with a light bulk specific gravity. ,
Problems such as separation may occur. On the other hand, if particles with a light bulk specific gravity are made, the surface area will increase, resulting in poor stability.Also, the strength of the particles will decrease, causing them to break during transportation, resulting in pulverization, resulting in a heavy bulk specific gravity, and other drawbacks. . In order to satisfy these properties, it is desirable that the particles be hollow and have dense shells. The present invention provides a method for manufacturing such a hollow PC at low cost.

That is, the present invention involves continuously or intermittently adding granular sodium carbonate and hydrogen peroxide to a solution containing sodium carbonate, hydrogen peroxide, and sodium chloride, and reacting at a temperature of 10 to 40°C to form hollow granular PC. When manufacturing, the mother liquor composition should be between 80 and 80% in terms of sodium chloride concentration.
290g/, sodium carbonate concentration 20-120
g/, 6 to 50 g/ for hydrogen peroxide concentration,
Regarding hexametaphosphate concentration 0.01-2.0g/
and the molar ratio of hydrogen peroxide to sodium carbonate is 1.8 or less, and the average particle diameter of the granular sodium carbonate to be added is
50 to 1000 μ, and the weight ratio of hexametaphosphate to the added granular sodium carbonate is 0.05/100 to 1.0/
Added at a ratio of 100 to 100, and using silicic acid compounds and magnesium compounds as stabilizers, the weight ratio of SiO ₂ to the added granular sodium carbonate is 0.05/100 ~
The present invention relates to a method for producing PC, characterized in that the produced sodium carbonate hydrogen peroxide adduct is added in a ratio of 1.0/100 and 0 to 0.2/100 as Mg, and is characterized in that it is in the form of stable hollow particles.

The mechanism of hollow PC formation is that when granular Na ₂ CO ₃ is added to a solution containing H ₂ O ₂ , the Na ₂ CO ₃ dissolves and reacts with H ₂ O ₈ as it diffuses offshore. A thin layer of PC with voids is first formed on the surface of the Na ₂ CO ₃ particles,
Na ₂ CO ₃ elutes from the inside through the voids, and the PC layer gradually thickens due to reaction with H ₂ O ₂ from the outside, resulting in hollow granular PC. , here the concentration of Na ₂ CO ₃ (dissolution rate and diffusion rate of added granular Na ₂ CO ₃ are also related), concentration of H ₂ O ₂ , reaction temperature, hexametaphosphate (hereinafter abbreviated as H・M・P). ) and the particle size of the added granular Na ₂ CO ₃ are required. These factors affect the thickness of the PC layer formed on the Na ₂ CO ₃ surface, the degree of voids, and the internal
This will significantly change the dissolution rate of Na ₂ CO ₃ , and if a dense layer is formed in the early stage of the reaction, the elution of Na ₂ CO ₃ covered inside will be completely stopped. For example, the concentration balance between Na ₂ CO ₃ and H ₂ O ₂ is
In a system in which H ₂ O ₂ is shifted in the direction of H 2 O 2 and H ₂ O ₂ exists in excess, such a phenomenon occurs and the reaction is inhibited. Furthermore, in the present invention, the addition of HMP is particularly important, as it has the effect of making the crystals of the PC layer denser, and also reduces the diffusion rate of Na ₂ CO ₃ and the rate of penetration of H ₂ O ₂ into the interior. It is possible to easily control the generation of PC shells and to widen the range of conditions for generation.Also, the shells produced are strong and have a smooth surface, which improves the fluidity of the product particles, and also increases the transport speed. It has many important effects, such as preventing PC from being destroyed, but when a large amount of HMP is added,
Since the density of the layer increases significantly, Na ₂ CO ₃ from inside
elution may be inhibited. or,
If the concentration balance between Na ₂ CO ₃ and H ₂ O ₂ is biased toward increasing the Na ₂ CO ₃ concentration, for example, increasing the reaction temperature will increase the solubility of Na ₂ CO ₃ and _{increase the}
The small particles in the reaction system dissolve quickly and
This causes the Na ₂ CO ₃ concentration to increase, and conversely, when the temperature decreases, the solubility and dissolution rate of Na ₂ CO ₃ particles decrease, which facilitates the formation of a PC layer on the surface of the raw material particles, but on the other hand, the internal Since the elution of Na ₂ CO ₃ from the inside is suppressed, this causes internal Na ₂ CO ₃ to remain without being completely reacted. Furthermore, when the concentration of HMP is low, the particles become fine. In view of the above, the reaction temperature is 10 to 40℃, preferably 20 to 30℃.
was selected, and the HMP mother liquor concentration was 0.01g/
Adjust and add H. within the range of 1 to 2 g/.
MP is based on the weight of granular Na ₂ CO ₃ added.
It is added in an adjusted range of 0.05/100 to 1/100. It is also possible to use HMP and sodium polyacrylate in combination, and the present invention can be carried out advantageously.

The mother liquor composition to be maintained is 80% with respect to NaCl concentration.
~290g/, 20~120g/ for Na ₂ CO ₃ concentration
, H ₂ O ₂ concentration is 6 to 50 g/, hexametaphosphate concentration is 0.01 to 2.0 g/, and the H ₂ O ₂ molar ratio to Na ₂ CO ₃ is adjusted to 1.8 or less.

What is important in obtaining hollow coarse PC is the particle size of the raw material Na ₂ CO ₃ used in the reaction. As can be seen from the formation mechanism of hollow PC, Na ₂ CO ₃ particles themselves are PC.
This is because it becomes the core of particle formation and is one of the major factors that determines the size of the generated PC particles.
That is, the average particle diameter of the raw material Na ₂ CO ₃ is 50 to 1000 μ.

If the slurry concentration of PC present in the mother liquor becomes too high, the slurry viscosity will increase, making it difficult to quickly disperse the supplied particulate Na ₂ CO ₃ and H ₂ O ₂ throughout the mother liquor. , the raw material is localized in the slurry liquid surface layer, etc., and the reaction proceeds in a localized system that deviates from the appropriate mother liquor composition range, which is undesirable because incomplete reaction tends to cause particles and refinement. The slurry concentration is set at an upper limit of PC350g/(slurry).

In the present invention, sodium chloride not only has the effect of improving the yield of PC due to its salting-out effect, but also has a great effect on adjusting the dissolution rate of Na ₂ CO ₃ and the precipitation rate of PC. In addition, when PC comes into contact with combustible materials, there is a risk of burning the combustible materials under certain conditions, but in the present invention, sodium chloride is incorporated into the PC crystals and acts as a diluent for the PC. It also has the effect of preventing danger.

In the method of the present invention, the stability of PC produced by adding a silicate compound such as sodium silicate and a magnesium compound such as magnesium sulfate as a PC stabilizer is significantly improved. The amount of silicic acid compound and magnesium compound added is
The respective addition ratios are 0.05/100 to 1.0/100 as SiO ₂ and 0.2/100 or less as Mg to the weight of Na ₂ CO ₃ added, and the silicate compound,
It is also possible to use the Mg compound in combination with a known stabilizer such as EDTA or phosphate.

By carrying out the present invention, it is possible to advantageously produce hollow granular PC with improved water solubility, stability and fluidity, and the present invention is an extremely advantageous production method industrially.

The present invention will be explained in detail below using examples.

Example 1 While stirring the mother liquor 10 having a composition of sodium chloride concentration 279 g/, sodium carbonate concentration 50 g/, and hydrogen peroxide concentration 6 g/, the concentration of 840μ or less
Granular sodium carbonate with a particle size of 99.7% and 25.8% below 300μ is supplied at a rate of 2.00Kg/hour, hydrogen peroxide at a concentration of 750g/hour is supplied at a rate of 1.32/hour, and at the same time a sodium hexametaphosphate aqueous solution with a concentration of 0.1g/ml is supplied at a rate of 68mL/hour. 18 ml of magnesium sulfate aqueous solution with a concentration of 0.5 g/ml per hour / 3 with a concentration of 0.5 g/ml per hour
No. sodium silicate was added continuously at a rate of 60 ml/hour, and the liquid temperature was maintained at 22°C during the reaction.

After 1 hour of reaction, the supply of granular sodium carbonate, hydrogen peroxide, sodium hexametaphosphate, magnesium sulfate, and No. 3 sodium silicate was stopped,
After stirring for 10 minutes, the slurry was extracted and separated into solid and liquid using a centrifuge. The filtrate contains 44.2g/for sodium carbonate and 16.4g/for hydrogen peroxide.
It had a concentration of Ten PC particles were randomly extracted, cut into two, and the inside of the particles was observed under an electron microscope, and it was confirmed that the particles were mostly hollow. In addition,
The effective oxygen content of the obtained PC was 14.0%, and the average particle size was 530.
μ, bulk specific gravity is 0.51, and NaCl and
The content of HMP was 3.7% and 0.11%, respectively.

Comparative example 1 The initial mother liquor composition was set to a sodium chloride concentration of 280 g/,
Sodium carbonate concentration 18g/, hydrogen peroxide concentration 6
The reaction was carried out under the same conditions as in Example 1, except that the amount was set to 1. After the reaction is complete, the mother liquor is sodium carbonate.
The obtained particles had a concentration of 21.3 g/, hydrogen peroxide 46.1 g/, and the resulting particles contained 9.2% effective oxygen and bulk specific gravity.
0.97, and unreacted sodium carbonate existed inside the particles surrounded by sodium carbonate-hydrogen peroxide adduct.

Example 2 Using the initial mother liquor 10 having a composition of sodium chloride concentration of 260 g/, sodium carbonate concentration of 50 g/, and hydrogen peroxide concentration of 6 g/, basically Example 1 was used.
Additives were fed at the same feed rate as in the case of sodium carbonate and hydrogen peroxide.
The sodium chloride concentration was adjusted intermittently to maintain a concentration of ~20g/260~270g/.
Continuous reaction was carried out by supplying sodium chloride to maintain the temperature. During the reaction, the slurry concentration is 250g/
The slurry was extracted and the filtrate after centrifugation was circulated in the reaction vessel. Reaction temperature is 23℃
And so.

The particle size of the raw material sodium carbonate is 840μ or less99.6
%, 34.3% of 300μ or less was used. generated
Cut the PC particles in the same manner as in Example 1,
When the inside of the particle was divided into two and observed under an electron microscope, it was found that most of the particles were hollow, with an effective oxygen content of 13.9 to 14.2%, an average particle size of 610μ, and a bulk specific gravity of 0.58. and HMP contents were 4.2% and 0.19%, respectively.

Comparative Example 2 The reaction was started under the same conditions as Example 2 except that sodium hexametaphosphate was not used, but 3 minutes after the start, fine acicular crystals of sodium carbonate hydrogen peroxide adduct precipitated and the slurry The viscosity of the reaction slurry increased, and after 20 minutes, the continuously supplied raw material sodium carbonate particles solidified on the surface of the reaction slurry without being dispersed, making it impossible to continue the reaction. , the reaction was stopped.

The adduct after dehydration and drying had an effective oxygen content of 12.5% and contained 67.4% of microcrystals of 150μ or less, making it unsuitable for general use.

Comparative example 3 NaCl does not coexist, sodium carbonate concentration 110g/
(10wt%), hydrogen peroxide concentration 44g/(4wt%)
While stirring, 2.0% sodium carbonate of the same particle size as used in Example 2 was added to the mother liquor consisting of 10%
Kg/hour, 1.32 hydrogen peroxide at a concentration of 750g/hour
Kg/hour, 68ml/hour of sodium hexametaphosphate solution with a concentration of 0.1g/ml, 18ml/hour of a magnesium sulfate solution with a concentration of 0.5g/ml, and a concentration of 0.5g/hour.
ml of No. 3 sodium silicate was continuously added at a rate of 60 ml/hour, and the reaction was carried out at a reaction temperature of 22° C. for 1 hour. After the reaction, the mother liquor obtained by filtration contained unreacted hydrogen peroxide at a high concentration of 87.2 g/mt. This is considered to be because the reaction between sodium carbonate and hydrogen peroxide did not proceed smoothly and the hydrogen peroxide in the mother liquor increased. The adduct particles after drying have an effective oxygen content of 8.4% and a bulk specific gravity.
It was a non-hollow particle with a diameter of 1.02.

Claims (1)

[Claims] 1. Particulate sodium carbonate and hydrogen peroxide are added continuously or intermittently to a solution containing sodium carbonate, hydrogen peroxide and sodium chloride, and the temperature is 10 to 10.
When reacting at 40°C to produce hollow granular sodium carbonate hydrogen peroxide adducts, the mother liquor composition has a sodium chloride concentration of 80 to 80°C.
290g/, sodium carbonate concentration 20-120
g/, 6 to 50 g/ for hydrogen peroxide concentration,
Regarding hexametaphosphate concentration 0.01-2.0g/
and the molar ratio of hydrogen peroxide to sodium carbonate is 1.8 or less, and the average particle diameter of the granular sodium carbonate to be added is
50 to 1000 μ, and the weight ratio of hexametaphosphate to the added granular sodium carbonate is 0.05/100 to 1.0/
Added at a ratio of 100 to 100, and using silicic acid compounds and magnesium compounds as stabilizers, the weight ratio of SiO ₂ to the added granular sodium carbonate is 0.05/100 ~
1.0/100 and Mg added at a ratio of 0 to 0.2/100. A method for producing a sodium carbonate-hydrogen peroxide adduct, characterized in that the produced sodium carbonate-hydrogen peroxide adduct is in the form of stable hollow particles.