JPH0585592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a non-dusting powder composition obtained by modifying a powder that easily dusts so that it does not dust easily.

Powdered industrial products are widely produced and handled in various industrial fields. Examples of these powders include fertilizers, pesticides, pigments, dyes, fillers, cement, gypsum, ceramics, coal, clay, livestock feed, and the like. As the constituent particles of these powders become finer, they tend to become powdery, and during operations such as weighing, packaging, and removal, they may generate dust, smoke, etc., worsening the working environment, or the powders may become flammable. Special precautions must be taken to prevent ignition and explosion accidents. In some cases, to avoid dusting,
In some cases, a wet granulation process is provided to convert the material into granules that do not stand up.

Prior Art In order to solve these problems with powders, there is a method of converting easily dusty powders into non-dust-producing powders by mixing powder with a substance that prevents the powders from dusting. For example, in JP-A-60-191084, polytetrafluoroethylene is added to slaked lime powder, and slaked lime fine particles are added to the web-like polytetrafluoroethylene produced by fibrillating the polytetrafluoroethylene. There is a known method for preventing the generation of dust from slaked lime powder by trapping it.

Problems to be Solved by the Invention The method disclosed in JP-A-60-191084 requires a step for fibrillating polytetrafluoroethylene, and the added polytetrafluoroethylene Since it accompanies slaked lime, it may cause harm depending on its use.

An object of the present invention is to provide a simple and efficient method for converting dust-producing powder into non-dust-producing powder, and another object of the present invention is to provide a method for easily and efficiently modifying dust-producing powder into non-dust-producing powder. An object of the present invention is to provide a dusty powder composition.

Means for Solving the Problems The non-dusting powder composition of the present invention is a sulfonic acid group-containing substance such as sulfonated products of methylolmelamine, methylolurea, or cocondensates thereof, salts thereof, and condensates thereof. It is characterized in that an effective amount of is uniformly contained in the dust-generating powder.

The dust-producing powders targeted by the present invention are various insoluble or poorly soluble industrial products that easily dust, such as slaked lime, chemical fertilizers, agricultural chemical powders, pigments such as titanium oxide, dyes, calcium carbonate, kaolin, Examples include fillers such as carbon black, cement, gypsum, ceramic raw materials, coal powder, clay, livestock feed, and earth and sand existing on road surfaces or the ground.

Examples of the sulfonic acid group-containing substance used in the present invention include sulfonated methylolmelamine;
Sulfonated products of methylol urea, sulfonated products of co-condensates of methylol melamine and methylol urea, salts of these sulfonates such as sodium salts, potassium salts, calcium salts, ammonium salts, sulfonated melamine formaldehyde condensates, sulfonated urea formaldehyde condensates Examples include salts such as sulfonated melamine urea formaldehyde cocondensates, sodium salts, potassium salts, calcium salts, and ammonium salts of these condensates or cocondensates. These sulfonic acid group-containing substances are known water-soluble substances and can be easily produced by known methods.

The non-dusting powder composition of the present invention is obtained by adding a solution of the sulfonic acid group-containing substance to the dusting powder,
It can be easily obtained by uniformly mixing and, if necessary, drying. In some cases, for example, an aqueous solution of the above-mentioned sulfonic acid group-containing substance is added to quicklime and mixed uniformly under pulverization if necessary.
It can also be obtained by adding a solution of a sulfonic acid group-containing substance to the raw material of the dust-generating powder in advance and mixing the mixture uniformly. The amount of the sulfonic acid group-containing substance added may be an effective amount sufficient to change the dust-producing property of the powder to non-dust-producing property. This effective amount usually increases as the powder particles become finer, but is preferably about 0.02 to 5% by weight based on the powder. For example, 1
For slaked lime powder consisting of particles of ~3μ,
It is preferably about 0.1 to 0.3% by weight. Further, the concentration of the solution of the sulfonic acid group-containing substance to be added is not particularly limited, but is usually preferably 1 to 10% by weight. Excessively highly concentrated solutions tend to make it difficult to achieve uniform mixing in a short time. A particularly preferred non-dust-producing powder composition is such that a 3-7% by weight aqueous solution of a sodium or potassium salt of a sulfonated melamine formaldehyde condensate is added to the above-mentioned dust-producing powder to give a solid content of 0.2% by weight. It is obtained by adding in a spray form an amount of ~0.5% by weight and uniformly mixing in a powder mixer.

Effect When a large amount of a solution containing a sulfonic acid group is added to a dust-producing powder, a slurry is formed, which is undesirable as it requires a drying process to reconstitute it into a powder. When a solution of the contained substances is added and mixed uniformly, the resulting composition does not generate dust even though it is a powder. Although the powder composition immediately after mixing contains the solvent from the solution, the powder composition obtained by subsequent drying also does not exhibit dusting properties. This effect of preventing powder dust generation is thought to be due to the fact that powder particles that are in contact with each other and covered with a sulfonic acid group-containing substance are difficult to be separated by a weak external force. .

Example 1 To 100 parts by weight of slaked lime powder for fertilizers with a size of 1 to 3μ, 8 parts by weight of a 5% by weight aqueous solution as a solid content of sodium salt of a sulfonated melamine formaldehyde condensate (clay content at 25°C is 3 cp) was added. A powder composition (A ₁ ) was obtained by feeding the mixture into a powder mixer from a sprayer and mixing under closed conditions for 10 minutes. Also,
This composition (A ₁ ) was dried under reduced pressure at 50°C to obtain a powder composition (A ₂ ).

1/4 of the internal volume of each of these powder compositions (A ₁ ) and (A ₂ ) was taken into a transparent glass bottle, the bottle was tightly capped, and then shaken vigorously, but almost no dust was generated in the bottle. . Separately, 10 g of each of the above powder compositions (A ₁ ) and (A ₂ ) were placed on a glass plate, and from a height of 100 cm above the ground in a natural leeward direction, the glass plate was gently tilted toward the ground. Although it fell, there was hardly any dust caused by the wind.

On the other hand, as a comparison, when the slaked lime powder to which the sodium salt of the sulfonated melamine formaldehyde condensate was not added was shaken in a transparent glass bottle in the same manner as above, white dust was generated throughout the bottle, and natural Even when the above weathering test was performed, dust was still observed to be generated by the wind during the fall from the glass plate.

Example 2 A 7% by weight aqueous solution (viscosity at 25°C of 5 cp as solid content) of the sodium salt of a sulfonated melamine formaldehyde condensate was prepared for each of titanium dioxide pigment, calcium carbonate filler, and carbon black filler, all of which exhibit dust-generating properties. ) was added to the powder composition (B ₁ ) in the same manner as in Example 1, except that 12.8 parts by weight of the titanium dioxide pigment (B 1 ) was added and mixed for 15 minutes.
A powder composition (C ₁ ) was obtained from the calcium carbonate filler, and a powder composition (D ₁ ) was obtained from the carbon black filler. By further drying (B ₁ )
From (B ₂ ), (C ₁ ) from (C ₂ ), (D ₁ )
From this, each powder composition (D ₂ ) was obtained.

Next, in the same manner as in Example 1, the above (B ₁ ),
For each sample (B ₂ ), (C ₁ ), (C ₂ ), (D ₁ ), and (D ₂ ), a shaking test in a transparent glass bottle and a natural downwind powder dusting test were conducted. Almost no dust was generated in any of the samples.

Example 3 A 10% solids aqueous solution of sodium salt of sulfonated urea formaldehyde condensate (viscosity at 25°C
A powder composition (E ₁ ) of slaked lime for fertilizer was obtained in the same manner as in Example 1, except that the mixing time was 15 minutes, and a powder composition (E ₂ ) was obtained by drying. Ta. These (E ₁ ) and (E ₂ ) were subjected to a shaking test in a transparent glass bottle and a natural downwind powder dusting test in the same manner as in Example 1, but all samples showed almost no dust generation. Ta.

Effects of the Invention According to the present invention, by simply adding a solution of a specific compound containing a sulfonic acid group to an insoluble or poorly soluble dust-producing powder and uniformly mixing it, a non-dust-producing powder can be produced extremely easily and efficiently. You can get a body. The sulfonic acid group-containing substance used in the present invention is a harmless substance, so even if a small amount of it accompanies the powder,
Not harmful in most applications. In fact, in some cases, this substance may have a useful effect. For example, when added to a powdered fertilizer, it aids in the fertilizing effect of this fertilizer. Furthermore, since the non-dust-producing powder of the present invention generates almost no dust during its handling operations, not only the working environment is not harmed, but also powder loss is reduced.

Claims (1)

[Claims] 1. An effective amount of one or more sulfonic acid group-containing substances selected from the group consisting of sulfonated products of methylolmelamine, methylolurea, or cocondensates thereof, salts thereof, and condensates thereof is added to dust-producing powder. 1. A non-dust-producing powder composition characterized by uniformly containing .