JPS5839880B2 - How to use the new technology - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing granular detergents containing water-insoluble or poorly water-soluble inorganic salts.

Generally, granular detergents are obtained by spray-drying a slurry whose main components are surfactants and detergent aids such as sodium tripolyphosphate and CMC (carboxymethylcellulose) fluorescent dye. Phosphates are generally used in large amounts because they are effective in improving the detergency, mechanical strength, and hygroscopic solidification of products.

However, as eutrophication of rivers due to phosphates has become a problem in recent years, there is a trend toward avoiding the use of large amounts of phosphates.

On the other hand, detergents that use a large amount of alkali builders such as sodium silicate and soda carbonate instead of phosphates are also known.

Although it is possible for such detergents to have the same level of cleaning power as phosphate-based detergents, they are highly hygroscopic, and during storage, they tend to aggregate due to moisture absorption, resulting in so-called clumps that reduce the product value. .

In order to prevent the hygroscopic solidification of non-phosphate granular detergents, methods of adding lower alkyl sulfates, polycarboxylate salts, silica, etc. have been proposed, but the effects are not sufficient.

Furthermore, a method of adding a weak alkali metal salt of a strong acid such as magnesium sulfate has been proposed, but the conventional addition method does not provide sufficient effects and is not practically satisfactory.

In the present invention, the drawbacks of non-phosphate granular detergents are eliminated by adding an aqueous solution of a weak alkali metal salt of a strong acid to a detergent slurry containing a sufficient amount of alkali silicate at a rate below a certain rate, We have discovered a method for producing granular detergent that has improved moisture absorption and solidification properties and does not form lumps.

That is, the method of the invention contains a surfactant and an alkali silicate in an amount sufficient to react with a weak alkali metal salt of a strong acid such as hydrochloric acid, sulfuric acid or nitric acid, and optionally other alkali builders or other cleaning aids. slurry,
0.3-10% by weight of the aqueous solution of the weak alkali metal salt of the strong acid was added at 1001 mol/d based on the total solid content in the slurry.
This is a method for producing a granular detergent, characterized in that the detergent is added at an addition rate of less than 1 minute.

In the method of the present invention, the reaction between the weak alkaline earth salt of the strong acid and the alkali silicate is preferably carried out at a temperature of 20 to 80°C, but the temperature is not particularly limited to this range.

The amount of the weak alkali metal salt of the strong acid is suitably 0.5-10% by weight based on the total solid content of the slurry, and the amount of the alkali silicate is an amount sufficient to react with the weak alkali metal salt and the final Use an amount that will keep the detergent slurry alkaline.

This reaction produces water-insoluble or poorly soluble fine particles with an average particle size of 10 μm or less, which is effective in improving moisture absorption and solidification properties.

The concentration of the weak alkali metal salt aqueous solution is not particularly limited, but a range of about 5-30% by weight gives preferable results.

Further, any method of addition may be used as long as the addition rate is 100 f-+7711 minutes or less, but it is preferable to add it continuously in the form of a spray.

Further, during the reaction, use of a homomixer, a disvermill, etc. can suppress the generation of coarse particles, and even better results can be obtained.

The fine particles thus obtained are considered to be an inorganic compound having a composition of 5 in 263-70%, 5% or less alkali, 5% or less acid residues, the metal involved in the reaction, and a small amount of ignited volatile matter.

Note that if the amount of the weak alkali metal salt of the strong acid is less than 0.5% by weight, the effect of preventing absorption and solidification of the granular detergent cannot be obtained;
If it exceeds 0% by weight, the amount of insoluble fine particles becomes too large, resulting in a decrease in the solubility and detergency of the detergent.

Furthermore, if the addition rate is set to 1005 i'mol/d min or higher, the average thickness of the particles produced increases, and the production of coarse particles increases, making it impossible to obtain the desired effect.

Next, after the reaction is complete, if necessary, various detergent ingredients such as surfactants, virgoo, and detergent auxiliaries are added and mixed.
The granular detergent of the present invention can be obtained by spray drying according to a conventional method.

The weak alkali metal salt used in the present invention may be any water-soluble acidic salt having a pH of 5.5 or less that reacts with an alkali silicate to form a water-insoluble or poorly water-soluble compound, such as Mg, Ca, Zn, AI, Co, M
Examples include hydrochloric acid, sulfuric acid, nitrate, etc.

Further, as the alkali silicate, Na salt, K salt, etc. can be used.

Any conventional surfactant and detergent auxiliary agent can be used.

That is, surfactants include anionic surfactants such as alkylaryl sulfonates, α-olefin sulfonates, and alkyl sulfates, and nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkylphenyl ether. As adjuvants carbonate, phosphate,
Any of borates, organic polycarboxylates, CMC1 fluorescent agents, bleaches, etc. can be used.

However, when using a phosphate, it is preferable to use as little amount as possible from the above-mentioned viewpoint.

The granular detergent obtained by the method of the present invention has almost no hygroscopic solidifying property, and even if it does, the rate of hygroscopic absorption is slow, and even if clumps occur, it has a free-flowing feel and breaks with the slightest impact.

Moreover, the detergent's solubility, detergency, and foaming properties are excellent.

This effect is obtained because the water-insoluble or poorly soluble fine particles generated in the above reaction are present in a dense and concentrated state near or in contact with the surface of the detergent particles during spray drying, and they are also absorbed by the detergent and other ingredients. This is thought to be to prevent any negative effects.

This surface layer has a moisture retaining effect, prevents moisture from migrating into the detergent particles, and smooths the surface, giving the detergent a constantly flowing feeling.

It is also believed that the above-mentioned complex composition of the surface layer has a positive influence on the excellent effects of the present invention.

Note that the unit of addition rate in the present invention is 1 mol/m min.
It represents the number of moles calculated by r of the weak alkali metal salt of a strong acid added to the slurry of rn''.

Examples are shown below.

Examples 1 to 4 and Comparative Examples 1 to 4 1.5 kg of linear alkylbenzenesulfonate sodium, 0.9 k of sodium silicate (Si02/Nc20 molar ratio: 2)
g, soda carbonate 0.3 kg, sodium citrate 0.6 to 9
While stirring the slurry containing 0.06 kg of CMC and the balance amount of Glauber's sulfate in a blending tank equipped with a turbine type stirrer, the indicated amount of 20% by weight aqueous aluminum sulfate solution was added for 5 minutes (
In Comparative Example 2, the fluorescent brightener 0.06 kli+
was added to form a slurry with a water content of 40% by weight, and this was spray-dried to obtain a granular detergent.

In the case of this example, the average particle size (Stokes diameter) of the generated particles is 0.5-5μ, and the true specific gravity is about 2. o?
/ml.

Aluminum silicate has a pharmacopoeia light average Stokes diameter of 8.7
μ, true specific gravity 2. Of/rule was used.

The results are as follows.

*1: Moisture permeability of sample 500P is approximately 200? /m'・24
Place in a paper container and seal.

After being left for 24 hours under conditions of 35° C. and 95% RH, the amount of lumps was determined from the weight ratio of the moisture absorption amount to the total amount of the lump-solidified portion (clumps) based on the increase in weight.

*2: Granular detergent sample with a diameter of 1 cfrL and a depth of 1 cIrL.
Place it in a tablet molding machine and apply a load of 5001 from the top and bottom to make a tablet.

This tablet is broken with a glass needle, and the solidification failure value is determined by the maximum load applied at that time.

It expresses the breakability of solidified matter (clumps) numerically, and the smaller the breakage value, the better the granular detergent.

Examples 5 to 10 In Examples 1 to 4, granular detergents** were prepared by using 5% aqueous solution of hydrochloride of various metals instead of aluminum sulfate,
The results of a similar test are shown in the table below.

Note that the addition rate of the hydrochloride was 20-602 mol/d·min.

Example 11-13 In Example 1-4, the amount of aluminum sulfate was changed to 3
% and when an aqueous solution of 3% aluminum chloride or 3% aluminum ☆☆nium nitrate was used instead of aluminum sulfate, and the properties of the granular detergent were similarly tested.

The results are shown in the table below.

Claims (1)

[Claims] 1. A method for producing a granular detergent by mixing a surfactant, an alkali silicate, a weak alkali metal salt of a strong acid such as hydrochloric acid, sulfuric acid or nitric acid, other detergent auxiliaries and water, and spray-drying the resulting slurry. , the amount of the weak alkali metal salt of the strong acid is 0.5-10% by weight based on the total solid content in the slurry, and the amount of the alkali silicate is equal to or more than the equivalent molar amount of the weak alkali metal salt of the strong acid; A method for producing a granular detergent, which comprises adding the weak alkali metal salt of the strong acid as an aqueous solution to a slurry containing an acid alkali at an addition rate of 1001 mol/d min or less.