JPH04164077A - Method for preventing powder from consolidating - Google Patents

Abstract

PURPOSE:To suppress water absorption and sublimation of powder and prevent the powder from mutually contacting and consolidating by addition thereof in a small amount by using polyethylene-piperazines as a consolidation inhibitor for the powder. CONSTITUTION:Poly-1,4-ethylene-piperazines are used as a consolidation inhibitor for powder [e.g. piperazine, triethylenediamine (TEDA), ammonium sulfate, ammonium chloride or sodium chloride] to prevent the powder from consolidating. Furthermore, the amount of the consolidation inhibitor used is preferably 0.005-0.02 pt.wt. based on 100 pts.wt. powder. The aforementioned inhibitor is normally added by a method for mixing the powder with a solution of the poly-1,4-ethylene-piperazines in water or an organic solvent using a mixer such as a ribbon blender after production of the powder.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for preventing and suppressing caking of powder having caking properties, and more specifically, a method for preventing and suppressing caking of powder having caking properties, and more specifically, a method for preventing and suppressing caking of powder having caking properties. Concerning the anti-caking method used.

(Prior art) Generally piperazine, triethylenediamine (hereinafter TED)
Powders of amines such as A) are condensable, adhesive, and easily solidified compounds.In addition to these powders, powders with strong hygroscopicity and powders with strong sublimation properties are , caking occurs easily due to the inclusion of a small amount of moisture or an increase in temperature. For this reason, these powders with caking properties require special care in handling, and if the powders solidify, they become extremely difficult to handle. Measures to prevent caking of these powders with caking properties include increasing the particle size of the powder itself, removing impurities in the powder, adding anti-caking agents to the powder, or using airtight containers. At present, this is carried out as appropriate by means such as storing the powder.

However, some powders with caking properties, such as piperazine, still caking even when stored in a closed container.
There are also substances with strong sublimation properties, such as TEDA, which promote solidification even if the purity is increased. As described above, it is currently difficult to find a method for preventing caking of these powders. Furthermore, since these powders have extremely strong caking properties, it is usually difficult to prevent caking by slightly enlarging the particle size.

Therefore, it is generally considered that the addition of an appropriate anti-caking agent is effective in preventing caking of such highly caking powders.

When selecting an anti-caking agent, select an anti-caking agent that can effectively achieve its purpose by adding as little amount as possible, and that does not cause coloring or odor to the powder due to the additive. There is no effect on the physical properties of the powder for the purpose of use.
Furthermore, an inexpensive anti-caking agent is desired.

As a conventional anti-caking agent, silica powder (JP-A-57-2
No. 03039) and polyethylene glycols (Special Publication No. 6
No. 3-46758), etc. are known. However, silica powder only temporarily avoids contact between crystals and does not have a very strong long-term anti-caking effect. Also, liquid anti-caking agents such as polyethylene glycols are TED
It is sufficient to simply mix it with powder A, but as a result, the TEDA powder becomes wet, and during long-term storage, the liquid material flows to the bottom of the storage container, making it non-uniform within the container and reducing the anti-caking effect. In addition, any anti-caking agent must be added at a relatively high concentration;
This results in a decrease in the purity of TEDA.

In contrast, Special Publication No. 6B-62241, Special Publication No. 64-
In No. 3142, by adding TEDA polymer, which is a polymer of TEDA, to the crystallization process as an additive, it becomes possible to simplify the process associated with addition and facilitate process control, and TEDA polymer has a high degree of anti-caking property. shows the effect,
It is disclosed that the effect can be sufficiently achieved by adding a very small amount. However, this TEDA polymer had a high molecular weight and was insoluble in most organic solvents.

(Problems to be Solved by the Invention) Many powders generally have cohesive and adhesive properties, and operations such as granulation and classification are performed to improve these properties. However, powders that have solidification properties, such as TEDA, which have strong sublimation properties, repeatedly sublimate and condense due to changes in external temperature, forming strong bridges between the powders (crystals). . As a result, the TEDA solidifies completely within the container and does not easily collapse.

TEDA is generally synthesized and manufactured from N-aminoethylpiperazine or hydroxylethylpiperazine. If these methods are used, TEDA can be obtained as pale yellow white crystals.

It also contains alkylpiperazine and the like as by-products. This by-product had some caking inhibiting effect.

However, as a result of the demand for high-purity TEDA crystals in recent years, improvements in purification technology have resulted in more than 99.9% T.
EDA crystals have been produced. As a result, the solidification properties of TEDA have increased rapidly, causing problems in the manufacturing process and storage.

An object of the present invention is to produce a powder that has caking properties.
It is an object of the present invention to provide a method for preventing the caking of powder using 1,4-ethylenepiperazine, which does not affect the physical properties of the powder and can be carried out effectively by adding a small amount.

(Means for Solving the Problems) As a result of intensive studies in view of the above-mentioned current situation, the present inventors have found that by using poly-1,4-ethylenepiperazine as an anti-caking agent, powders can be effectively consolidated. The present invention has been achieved by discovering that this can be suppressed.

That is, the present invention provides a method for preventing caking of caking powder, which uses poly-1,4-ethylenepiperazines and suppresses caking by adding them to the powder.

The details will be explained below.

Powder having caking properties in the present invention includes piperazine,
It refers to powders with extremely strong adsorption and sublimation properties, such as TEDA, ammonium sulfate, ammonium chloride, and sodium chloride.

There are two main causes of powder caking: absorption of moisture and formation of bridges between powders (crystals) due to sublimation and condensation. The issue is being addressed through measures such as strengthening quality control. In the latter case, no effective method has been found that does not affect the physical properties of the powder and also satisfies the other conditions. The present invention provides an extremely effective method for preventing caking by adding an anti-caking agent that suppresses the effects of water absorption and sublimation and condensation.

In the present invention, poly-1,4-ethylenepiperazines are represented by, for example, the following general formula (1) (where n is 1
The above integer, R1-12 is H or an alkyl group,
R13 is a piperazyl group. ) To give a concrete example,
Poly-1,4-ethylenepiperazine, poly-1,4-ethylene(2-methyl)piperazine, poly-1,4-(1
-methyl)ethylenepiperazine, etc.

The method for synthesizing the poly-1,4-ethylenepiperazines of the present invention is not particularly limited, but a preferred method is, for example, by refluxing a piperazine derivative and a bifunctional alkene such as ethylene dichloride in an aqueous solvent. In this method, the reaction is carried out at the bottom, and after the reaction is completed, it is treated with caustic soda. In this case, the average molecular weight of BoIJ-1.4-ethylenepiperazines is 400 to 600, and the yield is also extremely high, at 99% or more. Furthermore, the obtained poly-1,4-ethylenepiperazines exhibit excellent solubility in acidic aqueous solutions and various organic solvents.

In the present invention, the amount added to the powder having caking properties is not particularly limited as the amount added varies depending on the type of powder, but it is usually 1 part by weight or less per 100 parts by weight of the powder. Used in addition.

The characteristic feature of the present invention is that 0.001 to 0
．． 1 part by weight, preferably 0.005-0.02'ff1
The object of the present invention can be sufficiently achieved with an extremely small addition amount of ffi parts.

The mechanism of preventing caking in the present invention is considered as follows. Poly-1,4-ethylenepiperazines exhibit excellent solubility in various solvents. A solution of this poly-1,4-ethylenepiperazine in water or an organic solvent is mixed with powder and dried to form a thin film on the surface of the powder, thereby microcapsulating the crystals. It is thought that this blocks contact between the crystal-forming components and the outside air or between the crystals and suppresses sublimation and condensation, thereby suppressing the mutual condensation of the crystals and providing an anti-caking effect.

According to the present invention, the method of adding poly-1,4-ethylenepiperazine to the powder is not particularly limited, but for example, after producing the powder, a mixing device such as a ribbon blender or a V-type mixer is used. Using powder and poly-1,4-
A common method is to thoroughly mix ethylene piperazine with a solution of water or an organic solvent. However, if these mixing devices are used, the process will be complicated and the cost will be considerable. On the other hand, in the deliquification step immediately after crystallization, the TEDA crystal cake in the centrifuge is
By spraying a solution of 1,4-ethylenepiperazines in water or an organic solvent or adding them in various ways and drying, TE can be prepared without the need for any mixing equipment.
The DA crystal surface can be efficiently and uniformly coated. It may also be added during the crystallization process as shown in Japanese Patent Publication No. 63-62241.

The anti-caking agents currently used are silica powder and polyethylene glycols, but these additives have low anti-caking ability. About 1 part by weight is required, whereas in the present invention poly-1,4-ethylenepiperazines are mixed with TEDA10 in order to form a thin film on the powder surface.
If poly-1,4-ethylene piperazine is contained in an amount of 0.001 part by weight or more based on 0 parts by weight, an anti-caking effect is observed, but the larger the amount added, the more the anti-caking effect tends to be. be. However, as the amount added to the powder increases, the purity of the powder decreases, so it is desirable that the amount added be as small as possible. According to the present invention, the amount to be added to the powder is 0.001 part by weight to 1 part by weight, preferably 0.005 part by weight to 0.01 part by weight, per 100 parts by weight of the powder. Appropriate. This addition amount corresponds to 1/100 to 1/1000 of that of conventional additives.

Furthermore, poly-1,4-ethylenepiperazines are extremely stable chemically, so they have little effect on the physical properties of powder, and they also show excellent solubility in various solvents, making them useful as additives or coatings. It has extremely excellent properties as an agent.

(Effect of the invention) In this way, the present invention adds a very small amount of poly-1,4-ethylenepiperazine to powder and coats the surface of the powder to suppress water absorption and sublimation of the powder. An epoch-making anti-caking agent that not only provides excellent anti-caking effect to prevent contact between particles, but also allows the anti-caking agent to be quickly dissolved in the solvent without being suspended in the solvent when dissolving powder (crystals). It's technology.

(Example) Specific examples of the present invention are shown below, but the present invention is not limited thereto.

Example 1 100 g of piperazine, 100 g of ethylene dichloride, and 200 g of pure water were placed in a flask with an internal volume of 1000 g, and reacted under reflux in an oil bath until the liquid temperature began to rise. After the reaction was completed, the mixture was sufficiently cooled and an excess amount of caustic soda was added. After precipitating the produced poly-1,4-ethylenepiperazine and separating the supernatant, the poly-1,4-ethylenepiperazine was separated by filtration.
1°4-ethylenepiperazine was separated. After thorough washing with pure water, vacuum drying was performed to obtain 115 g of poly-1°4-ethylenepiperazine. Molecular weight distribution is 400~
1000, average molecular weight was 500, and showed excellent solubility in acidic aqueous solutions and organic solvents such as methanol.

T with a purity of 99.95% or more was used for the caking property test.
EDA powder was used, and poly-1,4-ethylenepiperazine synthesized by the above manufacturing method was used as an anti-caking agent. The addition was carried out by coating the TEDA surface with poly-1,4-ethylenepiperazine using the following method.

A 500 g TEDA cake was prepared on a Buchner funnel and added with 20 g of a 0.5% alcoholic solution of the above anti-caking agent.
After adding 0- and mixing thoroughly to bring the solution into contact with the TEDA crystals, filtration was performed and the TEDA crystals were taken out. The crystals were sufficiently dried under vacuum to obtain a 430 g sample. The coating amount is 0.03g (additive concentration in crystal)
(Similarly shown below) was near 0 ppm).

The measurement method and criteria for solidified dust are as follows. The obtained sample is packed into a container with a length of 5 cm and a height of 2 cITl, and a plastic plate with a length of 5 cm is placed on top.

A 300 g weight was placed on top of the sample, and the sample was stored in a desiccator at a humidity of 1% or less. At this time, the pressure applied to the crystal is 1
It is 2g/c.

After being stored in a desiccator for one month, the weight and container were removed, the plastic plate was placed face down, and pressure was applied to the central part of the crystal mass using a bookstore type hardness tester to read the pressure at the time of pulverization.

The values obtained in this way are classified into the following three ranks,
It was evaluated as an indicator of solidified dust. The results are shown in Table 1. As is clear from Table 1, it was ranked A and was found to have an excellent caking inhibiting effect.

As a result, it was ranked A in terms of the caking dust index, indicating that it had an excellent caking inhibiting effect.

Palanque: At a crushing pressure of 1.0 kg/cJ or less, solidification has hardly progressed and the block is crushed by a minute impact.Crystal B rank: At a crushing pressure of 10.0 kg/cd or less , C-rank crystals that have fully consolidated and the block will not be crushed by a mild impact...Consolidation has progressed completely at a crushing pressure of 10.0 kg/c- or more, and the block is quite strong enough to be crushed. Example 2 of a crystal in which blocks requiring impact are formed In a flask with an internal volume of 1000 rd, 100 g of 2-methylpiperazine, 100 g of ethylene dichloride, and 2 ml of pure water are placed.
00rd was added and reacted under reflux in an oil bath until the liquid temperature started to rise. After the reaction was completed, the mixture was sufficiently cooled and an excess amount of caustic soda was added. The produced poly-1,4-ethylene (2-methyl) piperazine was precipitated, the supernatant was separated, and poly-1,4-ethylene (2-methyl) was separated by filtration.
methyl)piperazine was separated. After thoroughly washing with pure water and vacuum drying, poly-1,4-ethylene (2
115 g of -methyl)piperazine were obtained. The molecular weight distribution is 3
00 to 1200, and the average molecular weight was 600, and showed excellent solubility in acidic aqueous solutions and organic solvents such as methanol.

Coating was performed in the same manner as in Example 1 using the obtained poly 1,4-ethylene (2-methyl) piperazine. The coated TEDA crystals were thoroughly dried under vacuum to obtain a 350 g sample. The coating amount was 0.07 g (200 ppm).

The degree of caking of this sample was evaluated in the same manner as in Example 1, and the result was A rank, indicating that it had an excellent caking inhibiting effect.

Comparative Example 1 The same operation as in Example 1 was performed except that no anti-caking agent was used. The results are shown in Table 1.

Comparative Example 2 A TEDA methanol solution having a composition of 5 parts of TEDA and 50 parts by weight of methanol was added to an internal volume of 50
00 mj flask, and 0.15 g of TEDA polymer obtained by the synthesis method described in JP-A No. 63-62241, that is, cationic polymerization method, was added. T at this time
The EDA polymer had an average molecular fn of 2,800 and a molecular weight distribution of 400 to 7,000. This solution was demethanoled using an evaporator to distill out 1,100 d of methanol, which was then allowed to stand at room temperature and cooled to a liquid temperature of 20°C.

The precipitated TEDA crystals were suction-filtered using No. 50 filter paper, and then vacuum-dried to obtain 450 g of TEDA crystals. At this time, the TEDA polymer contained in the TEDA crystal is 0.
．． It was 0.4g.

The degree of consolidation of this sample was evaluated in the same manner as in Example 1. The results are shown in Table 1. As shown in Table 1, it exhibited an excellent caking inhibiting effect, but when made into a 33% by weight dipropylene glycol solution, some turbidity occurred.

Comparative Example 3 500 g of TEDA and 2 g of silica gel (manufactured by Nippon Silikani Gyo Co., Ltd., bulk specific gravity 40 g/I, average particle size 2 μm) were thoroughly mixed in a V-type mixer, and then a sample was prepared. Other than that, the same procedure as in Example 1 was carried out. As shown in Table 1, some caking occurred.

Comparative example 4 rEDA500g and polyethylene glycol #200 (
Kanto Chemical) was thoroughly mixed in a V-type mixer to prepare a sample. Other than that, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 3 Using the poly-1,4-ethylenepiperazine obtained in Example 1, the coating amount and caking suppressing effect were compared. (1) 1% of poly-1,4-ethylenepiperazine;
(2) 0.5%, (3) 0.1%.

Example 1 except that (4) 0.05%, (5) 0.01% alcohol solution and (6) pure alcohol were used, respectively.
I did the same thing.

The TEDA yield, the coating amount of poly-1,4-ethylenepiperazine, and the caking suppression effect are shown in Table 2. As is clear from Table 2, a slight caking inhibiting effect was observed even at a coating amount of about 10 ppm, and 70
At ppm or more, an extremely excellent caking inhibiting effect is exhibited. Furthermore, no turbidity or floating matter was observed in various solvents such as alcohol, water, and glycols.

Example 4 Using the poly-1,4-ethylene(2-methyl)piperazine obtained in Example 2, the coating amount and caking suppressing effect were compared. Poly-1゜4-ethylene(2-methyl)piperazine (1) 1%, '(2) 0.5%, (3
) 0.2%, (4) 0. Example 1 was carried out in the same manner as in Example 1, except that 05% alcohol solution and (5) pure alcohol were each used.

TEDA yield, poly-1,4-ethylene (2-methyl)
Table 3 shows the coating amount and caking inhibition effect of piperazine.
Shown below. As is clear from Table 3, coating ffi1
A slight caking inhibiting effect is observed even at a concentration of about 5 ppm, and an extremely excellent caking inhibiting effect is observed at a concentration of 100 ppm or more.

Example 5 1000 g of an ammonium chloride aqueous solution having a composition of 35 parts by weight of ammonium chloride and 65 parts by weight of water was added to an inner volume of 2000 g.
- Poly-1,4 obtained in Example 1
- 0.5 g of ethylene piperazine was added. It was heated with a mantle heater, and the heating was stopped when 300 degrees of water had been distilled out.

The flask was immersed in a water bath and cooled to the liquid temperature of 20°C. The precipitated ammonium chloride is No.5C
It was suction filtered through filter paper and washed with a small amount of pure water. This was vacuum dried to obtain 92 g of ammonium chloride. At this time,
Poly-1,4-ethylenepiperazine contained in the crystal is 0
．． 023g (250ppI11). The degree of consolidation of this sample was evaluated in the same manner as in Example 1. The result was palanque.

Example 6 Coating was carried out in the same manner as in Example 5 except that poly-1,4-ethylene(2-methyl)piperazine obtained in Example 2 was used to obtain 88 g of ammonium chloride. At this time, poly-1,4-ethylene (
2-methyl)piperazine is 0.021g (239pp
+g).

The degree of consolidation of this sample was evaluated in the same manner as in Example 1, and the result was A rank.

Comparative Example 5 The same procedure as Example 5 was carried out except that poly-1,4-ethylenepiperazine was not added. Consolidation of the obtained sample had progressed to the inside, and the degree of consolidation was C rank.

Example 7 40 ammonium sulfate was added to a flask with an internal volume of 2000 mi.
1000 g of an aqueous solution of ammonium sulfate having a composition of 60 parts by weight and 60 parts by weight of water was added, and the
0.5 g of 1,4-ethylenepiperazine was added. It was heated with a mantle heater, and the heating was stopped when 400 rn1 of water had been distilled out.

The flask was immersed in a water bath and cooled until the liquid temperature reached 20°C. The precipitated ammonium sulfate is No. 5C.
It was suction filtered through filter paper and washed with a small amount of pure water. This was vacuum dried to obtain 230 g of ammonium sulfate. At this time, ammonium sulfate contained 0.05 g (217 ppm) of poly-1,4-ethylenepiperazine. The degree of consolidation of this sample was evaluated in the same manner as in Example 1.

The result was A rank.

Example 8 Coating was carried out in the same manner as in Example 7 except that poly-1,4-ethylene(2-methyl)piperazine obtained in Example 2 was used to obtain 210 g of ammonium sulfate. At this time, the poly-1,4-ethylene (2-methyl) piperazine contained in the crystal was 0.045g (214p
pm+).

The degree of consolidation of this sample was evaluated in the same manner as in Example 1, and the result was A rank.

Comparative Example 6 The same procedure as Example 7 was carried out except that poly-1,4-ethylenepiperazine was not added. Consolidation of the obtained sample had progressed to the inside, and the degree of consolidation was C rank.

Example 9 The same operation as in Example 2 was carried out except that piperazine and propylene dichloride were used in place of 2-methylbiperazine and ethylene dichloride, and poly-1,4
120 g of -(1-methyl)ethylenepiperazine was obtained.

The molecular weight distribution was 300-1000, and the average molecular weight was 500.

As a result of the coating process, 350 g of TEDA was obtained, and the coating amount was 0.07 g (200 ppm). The degree of caking was ranked A in the index, and the effect of preventing caking was recognized.

Claims (1)

[Claims] A method for preventing caking of powder, comprising using poly-1,4-ethylenepiperazine as a powder caking inhibitor.