JPS6241658B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing water-insoluble powder metal soap having large particles. Conventional methods for producing metal soap powder can be roughly divided into two methods: direct method, which involves the reaction of fatty acids with metal oxides or metal hydroxides, and double decomposition method, which involves reacting fatty acid alkali metal salts or metal hydroxides. There is a production method by reacting an aqueous solution of fatty acid ammonium salt with a metal salt (hydrochloride, sulfate, nitrate, acetate, etc.). Metal soap powder produced by the double decomposition method contains less free fatty acids because the reaction is carried out in the absence of fatty acids.
It has various advantages over the direct method, such as the fact that the particles are fine and easy to disperse, and the contamination of different metals (Fe, Pb, Mn, Cd) can be kept to a low level. However, the metal soap powder produced by the usual double decomposition method has the drawbacks of high hygroscopicity, strong adhesion, and poor fluidity because the average particle size is extremely small, about 5 μm. Therefore,
Even if it is sufficiently dried and in a satisfactory state at the time of manufacture, it adsorbs a large amount of water afterwards, causing problems during use, such as foaming and clouding when added to synthetic resins. In addition, in the plastics industry, which consumes large amounts of metal soap powder, automation through automatic weighing and pneumatic transportation is progressing, but metal soap powder with a small particle size produced by the ordinary double decomposition method has strong adhesion. The fluidity was poor, and troubles such as clogging in the piping and bridging in the hopper were likely to occur. As a result of intensive research, the present inventor found that these problems can be solved by increasing the particle size.
Furthermore, after adding or generating the desired fatty acid metal soap in advance, double decomposition reaction is carried out using an aqueous solution of fatty acid alkali metal salt or fatty acid ammonium salt in which the fatty acid metal soap is uniformly dispersed in the form of fine particles by stirring. They discovered that a fatty acid metal soap powder with large particles can be obtained by drying the soap powder, and completed the present invention. That is, in the present invention, when producing a C ₈ - C ₂₂ fatty acid metal soap powder by the double decomposition method, the target fatty acid metal soap is added in advance to an aqueous solution of a fatty acid alkali metal salt or a fatty acid ammonium salt, and the mixture is stirred. After uniformly dispersing the fatty acid metal soap in the form of fine particles, or by adding a portion of the metal salt aqueous solution in advance to an aqueous solution of fatty acid alkali metal salt or fatty acid ammonium salt, the desired fatty acid metal soap is produced, and then The process of discontinuing the addition of the metal salt aqueous solution and stirring to uniformly disperse the produced fatty acid metal soap in the form of fine particles, and then adding the metal salt aqueous solution to cause a double decomposition reaction. A method for producing fatty acid metal soap powder is provided. The fatty acid alkali metal salt or fatty acid ammonium salt used in the present invention is a _C8 to _C22 fatty acid, such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid. The metal salts include water-soluble metal salts such as hydrochlorides, sulfates, nitrates, acetates, etc. of metals such as barium, calcium, magnesium, strontium, and zinc. The fatty acid metal soap (hereinafter abbreviated as metal soap) powder according to the present invention is obtained by improving the conventional double decomposition method, so it has all the advantages of metal soap powder produced by the double decomposition method, and has no disadvantages. It has significantly improved hygroscopicity and adhesion,
The average particle size was over 10 μm, about twice the particle size of conventional products, and when observed with an electron microscope, it was found to be large plate-shaped crystals with a smooth surface. Conventional products had small particle sizes and agglomerated. In the production method according to the present invention, for example, during the double decomposition reaction, the target substance is added in advance to an aqueous solution of fatty acid alkali metal salt or fatty acid ammonium salt (hereinafter referred to as alkali salt) at a temperature of usually 60 to 100°C, preferably 80 to 100°C. After adding 0.1 to 50% by weight, preferably 5 to 20% by weight of the final theoretical yield of the metal soap in powder or slurry form and stirring to uniformly disperse the metal soap in the form of fine particles. , by adding metal salts or by adding 0.1 to the theoretical yield in advance.
Add an amount of the metal aqueous solution to produce the desired metal soap of ~50% by weight, preferably 5 to 20% by weight to form the desired metal soap, then interrupt the addition of the metal salt aqueous solution and stir. After the generated metal soap is uniformly dispersed in the form of fine particles, the remaining metal salt aqueous solution is added to complete the reaction.The higher the reaction temperature is, the better the crystal growth of the metal soap will be. Desirably, a temperature of 80 to 95°C is particularly preferred. At this time, if the amount of metal soap that is uniformly dispersed in the form of fine particles is less than 0.1% by weight, it will have little contribution to crystal growth, and if it exceeds 50% by weight, the metal soap will not be sufficiently dispersed and the resulting metal soap will grow in crystal growth. is not done enough. The concentration of the alkaline salt aqueous solution used here is usually 3 to 20% by weight, preferably 5 to 15% by weight, particularly preferably 10% by weight.
The concentration of the metal salt aqueous solution is generally 10 to 40% by weight, although there is no particular restriction on the concentration range as long as the metal salt is dissolved in water. In order to suppress the water repellency of the metal soap, a small amount of anionic or nonionic surfactant may be added either before or after the double decomposition reaction. The large-particle metal soap powder obtained by the method of the present invention is filtered, washed, and dried according to conventional methods to become a product, but the wet cake moisture content is 40 to 50% by weight, which is higher than that of the conventional method (60 to 70% by weight). Since it is significantly lower, there is also the advantage that utility costs such as washing water and drying heat required for removing soluble salts can be significantly reduced. The present invention will be explained in more detail with reference to Examples below. Note that all percentages in the examples are percentages by weight. Example 1 104 g of stearic acid and solid caustic soda were placed in a stainless steel reaction vessel equipped with a stirrer and a heating device.
16.2g of sodium stearate (hereinafter referred to as Na-
An aqueous solution (denoted as St) was prepared. This Na-St aqueous solution was added with an average particle size of 5.3 μm obtained in Comparative Example 1 described later.
When 10g of calcium stearate (hereinafter referred to as Ca-St) powder was added and stirred for 30 minutes, Ca
-Semi-transparent Na with finely dispersed St uniformly dispersed-
It became an aqueous St solution. Add 120 g of a 20% calcium chloride (hereinafter referred to as CaCl ₂ ) aqueous solution to this aqueous solution at 80°C.
was added dropwise over 20 minutes, and the mixture was further stirred for 1 hour to complete the reaction. When the obtained Ca-St was dehydrated using a centrifuge, the moisture content of the wet cake was 45%. Wash this wet cake with water again, and
117g of Ca-St powder when dried in a hot air dryer at ℃
(Moisture: 0.5%) was obtained. Average particle size is 13.4μ
It was m. Comparative Example 1 104 g of stearic acid and solid caustic soda were placed in a stainless steel reaction vessel equipped with a stirrer and a heating device.
Add 16.2g and 1000g of water and heat to 80℃ while stirring to make a transparent Na-St aqueous solution. This Na−St
120 g of a 20% CaCl ₂ aqueous solution was added dropwise to the aqueous solution at 80° C. over 20 minutes, and the mixture was further stirred for 1 hour to complete the reaction. When the resulting Ca-St slurry was dehydrated using a centrifuge, the moisture content of the wet cake was 65%. This wet cake was further washed with water and dried with hot air to obtain 110 g of Ca-St powder (water content: 1.9%). The average particle diameter was 5.3 μm. Example 2 6 pieces of water in 10 reaction vessels equipped with a stirrer and a heating device
, stearic acid 556g, solid caustic soda 86.4g
g and heated to 90℃ while stirring to form a uniform Na
An aqueous solution of -St was prepared. 35 at 90℃ in this aqueous solution.
After adding 50 g of %CaCl ₂ aqueous solution over 5 minutes, the addition of further CaCl ₂ aqueous solution was temporarily suspended and stirring and heating were continued for 30 minutes, resulting in a semi-transparent mixture in which the Ca-St was uniformly dispersed in the form of fine particles. An aqueous solution of Na-St was obtained. Next, 320 g of a 35% CaCl ₂ aqueous solution was added to this aqueous solution at 90° C. over 20 minutes, and stirring was continued for an additional 30 minutes to ripen the product, and the product was placed in a pressure filter to dehydrate. The moisture content of this wet cake was 40%. This wet cake was further washed with water and dried in a hot air dryer at 110°C, resulting in 580g of Ca-St powder.
(Moisture: 0.7%) was obtained. The average particle size of this Ca-St powder was 12.3 μm. Comparative example 2 6 pieces of water in 10 reaction vessels equipped with a stirrer and heating device
, stearic acid 556g, solid caustic soda 86.4g
g and heated to 90℃ while stirring to form a uniform Na
An aqueous solution of -St was prepared. 35 at 90℃ in this aqueous solution.
After adding 370 g of % _CaCl2 aqueous solution over 55 minutes,
Stirring was continued for 30 minutes to age, and the product was dehydrated in a pressure filter. The moisture content of this wet cake was 60%. When this wet cake is further washed with water and dried in a hot air dryer at 110℃, Ca-St
575 g of powder (moisture: 1.4%) was obtained. This Ca
The average particle size of the -St powder was 6.3 μm. Example 3 In a 2 m ³ reaction tank equipped with a stirrer and a heating device, 10%
Prepared 100 kg of slurry containing Ca-St, 1 m ³ of water, 140 kg of stearic acid, and 101 kg of 20% caustic soda, 95
The mixture was stirred for 1 hour while being heated to .degree. C. to obtain a translucent Na-St aqueous solution in which Ca-St was uniformly dispersed in the form of fine particles. 20% _CaCl2 aqueous solution at 90 °C in this aqueous solution.
After dropping 150 kg over 30 minutes, stirring and heating were continued for an additional hour to complete the reaction. Generated Ca-St
When the slurry was dehydrated using a centrifuge, the wet cake moisture content was 45%. When this wet cake was further washed with water, stored and dried, 146.5 kg of Ca-St powder was obtained.
(Moisture: 0.9%) was obtained. Average particle size is 10.4μ
It was m. Comparative Example 3 In a 2 m ³ reaction tank equipped with a stirrer and a heating device, 1 part of water was added.
^m3 , stearic acid 140Kg, 20% caustic soda 101Kg
was charged and stirred for 1 hour while heating to 95°C to obtain a uniform Na-St aqueous solution. 90℃ in this aqueous solution
After 150 kg of a 20% CaCl ₂ aqueous solution was added dropwise over 1 hour and 50 minutes, stirring and heating were continued for another 1 hour to complete the reaction. When the resulting Ca-St slurry was dehydrated using a centrifuge, the moisture content of the wet cake was 63%. This wet cake was further washed with water, dehydrated and dried to obtain 135.8 kg of Ca-St powder (water content: 1.7%). The average particle diameter was 6.7 μm. Example 4 100 kg of stearic acid, 31.3 kg of 48% caustic soda, and 1 m ³ of water in a 2 m ³ reaction tank equipped with a stirrer and heating device.
was heated at 80℃, stirred for 1 hour, and then heated at 80℃.
20% zinc sulfate (hereinafter referred to as ZnSO ₄ ) aqueous solution 41.3
Kg was added dropwise over 10 minutes, and the mixture was further stirred for 30 minutes to obtain a translucent Na-St aqueous solution in which zinc stearate (hereinafter referred to as Zn-St) was uniformly dispersed in the form of fine particles. Further, 240 kg of 20% ZnSO ₄ was added dropwise at 80° C. over 20 minutes, followed by stirring for 30 minutes to complete the reaction. The wet cake produced by centrifugally filtering the Zn-St slurry had a moisture content of 43%. When this wet cake is further washed with water and dehydrated and dried, it weighs 110 kg and has a moisture content of 0.3%.
Zn-St powder was obtained. The average particle size was 11 μm. Comparative Example 4 104 kg of stearic acid and 32.6 kg of 48% caustic soda in a 2 m ² stainless steel reaction tank equipped with a stirrer and heating device.
Kg and 1 m ³ of water were charged and stirred for 1 hour while heating to 80°C to prepare a transparent Na-St aqueous solution. 80℃
Then, 293 kg of a 20% ZnSO ₄ aqueous solution was added dropwise, and the mixture was further stirred for 30 minutes to complete the reaction. The moisture content of the wet cake obtained by centrifugally filtering the generated Zn-St slurry is
It was 62%. Wash this wet cake with water again,
When dehydrated and dried, 115 kg of Zn-St powder (moisture: 0.6
%)was gotten. The average particle diameter was 6.2 μm. The wet cake moisture content, average particle diameter, and dynamic repose angle as an index of the fluidity of powder particles of the metal soap powders obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1. Figure 1 shows the change in water content over time of the metal soap powder obtained in Comparative Example 1.
Double scanning electron micrographs are shown in Figures 2-3. In addition, the average particle diameter was determined using a light transmission particle size distribution analyzer.
The dynamic angle of repose was measured using a three-ring dynamic angle of repose measuring device, and the change in moisture content over time was measured by placing completely dry metal soap powder in a constant temperature and humidity chamber at 25°C and 90% RH. Measurements were taken after leaving it as it was.

【table】

【table】 [Brief explanation of the drawing]

Figure 1 shows the change over time in the water content of the metal soap powders obtained in Example 1 and Comparative Example 1 (25°C, 90%RH).
FIG. 2 is a scanning electron micrograph of the metal soap powder obtained in Example 1, and FIG. 3 is a scanning electron micrograph of the metal soap powder obtained in Comparative Example 1. Note that the white line at the bottom left of the photo indicates a length of 5 μm.

Claims (1)

[Claims] 1. When producing C ₈ - _{C 22} fatty acid metal soap powder by double decomposition method, the desired fatty acid metal soap is added in advance to an aqueous solution of fatty acid alkali metal salt or fatty acid ammonium salt, and stirred to dissolve the fatty acid metal soap. After uniformly dispersing the metal salt in the form of fine particles, or by adding a portion of the metal salt aqueous solution in advance to an aqueous solution of a fatty acid alkali metal salt or fatty acid ammonium salt, the desired fatty acid metal soap is produced, and then the metal salt aqueous solution is The method of producing fatty acid metal soap powder with large particles is characterized in that the addition is interrupted and stirred to uniformly disperse the produced fatty acid metal soap in the form of fine particles, and then an aqueous metal salt solution is added to cause a double decomposition reaction. Production method.