JP2790082B2 - Antifreezing agent and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material used for melting snow and ice on roads and bridges in a cold region to flow away, or for preventing snow and ice from freezing. It also relates to its manufacturing method. In this specification, the above operation is collectively referred to as “freezing prevention”.

[0002]

2. Description of the Related Art Sodium chloride and calcium chloride are currently used to prevent freezing of roads and the like, but salt damage has become a problem. Therefore, some use calcium / magnesium acetate (generally called “CMA”) instead. CMA is
It has the advantage that it is not as effective as chloride in effect, but does not cause salt damage because it is biochemically decomposed in the environment. It is known that CMA has a double salt bonded in a ratio of 3 mol of CA and 7 mol of MA. This double salt has no water of crystallization and has 5% or less, usually about 1% of attached water.

[0003] The production of CMA consists of Ca (OH) ₂ and Mg.
It is carried out using a neutralization reaction in which (OH) ₂ is added to an aqueous acetic acid solution. As raw materials, lightly burned dolomite and those that control its reactivity by digesting it are inexpensive,
Many dolomite have a Ca / Mg ratio that is more Ca-rich than 3/7 above, so that Mg from another magnesium source
The one supplemented with O or Mg (OH) ₂ is used.

Various improvements have been attempted in the actual CMA production process. For example, a method of obtaining coarse CMA by strictly controlling the amount of water in the above-described neutralization reaction (Japanese Patent Application Laid-Open No. 62-267246). No. 1), a method of reacting an aqueous mixture of a CM base with acetic acid and aging the resulting CMA slurry to obtain a product having less dust and uniform particle size and less odor of acetic acid (JP-A-1-50220).
No. 0) has been proposed.

[0005] On the other hand, potassium acetate (hereinafter abbreviated as "PA") is also used as an antifreezing agent. Since the heat of fusion per unit weight of alkali metal acetate is higher than that of alkaline earth metal acetate, PA can be said to be a higher performance antifreeze, but the price is high, so it can be justified. It is used only in airports and other limited areas.

Accordingly, it has been proposed to use CMA and PA together (US Pat. No. 5,219,483).
PA shows the same cryoprotection in a smaller amount than CMA,
In addition, the fast-acting feature is complemented by the fact that CMA is inexpensive and slow-acting than PA. The aim is to achieve it. The composition of a typical CMA + PA (hereinafter abbreviated as “CMAK” according to the description of the above-mentioned U.S. Patent) is as follows: 75% by weight of CMA having C / M = 3/7 and P
A25% by weight.

The inventors believe that magnesium resources are more expensive than calcium because they mainly rely on imports,
A study was conducted to increase the price of A, while considering that dolomite is relatively abundantly produced in Japan, and if the calcined product or calcined-digested product can be used as it is, it will help to reduce the cost of antifreezing agents. As a result, CA, MA and PA form a ternary double salt, and the ternary double salt forms CMA.
And PA were found to be useful as a cryoprotectant combining the advantages of both.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel compound or composition as an antifreezing agent by utilizing the above-mentioned knowledge of the present inventors, which has higher performance than CMAK, but is less expensive. An object of the present invention is to provide a material which is not much different from CMA, and to provide a suitable method for producing such an antifreezing agent.

[0009]

Means for Solving the Problems CA-MA-P of the present invention
The ternary double salt A is represented by the formula Ca ₄ Mg ₃ K ₃ (CH ₃ COO) ₁₇ . Hereinafter, this is abbreviated as “CMPA”.

The antifreezing agent of the present invention is a composition containing the above ternary double salt as an active ingredient. That is, the main component is CMPA, and a small amount of another salt is mixed with the main component. As the “other salt”, CA, MA and PA are all present as a single salt and are mixed. Things, CMA
And PA, or CMA, CA and / or MA and P
Various forms are possible, such as a mixture of A, a mixture of one, two or three of CMPA and CA, MA, and PA, and a mixture of CPA and CMA. It goes without saying that these "other salts" assist the action of the above ternary double salt, and act as an antifreezing agent as a whole mixture.

From the standpoint of practical application to roads and the like, it is preferable that the above-mentioned antifreezing agent has a uniform particle size as much as possible. Such particles are convenient to spread evenly on the road with a mechanical spraying device.
It is also expected that the deicing agent sprayed on the ice and snow will not roll down the slopes and will increase the friction between the tires of the car and the ice and snow on the road surface as if sanded. If so, it is better to make the particle shape as square as possible.

The method for producing antifreeze particles of the present invention is characterized in that Ca (OH) ₂ and Mg (OH) ₂ obtained by digesting lightly burned dolomite.
To the mixture of the above, an aqueous solution in which CH ₃ COOK and an approximately equivalent amount of CH ₃ COOH are dissolved in the hydroxide is added, and the mixture is stirred and reacted to form the ternary double salt, and the ternary double salt is contained. It consists of drying and solidifying the paste-like material and crushing the solidified material. This makes it possible to obtain a (2 to 5 mm) square particle product having a size suitable for spraying.

[0013] The deicing agent must have a pH value in the range of 7 to 9 when dissolved in water. This pH
In order to assure CH ₃ C in the above neutralization reaction,
OOH must not be excessive. Excess CH ₃ CO
The presence of OH is also undesirable in that it gives the product an acetic acid odor.

[0014]

As described above, CMA and P are used as antifreezing agents.
When A is compared, CMA is effective for preventing freezing in a narrow sense because it has a large freezing point drop and is slow-acting, whereas PA has a large heat of fusion and is fast-acting, and has a high melting-ice effect. .

The antifreeze according to the present invention has both properties of CMA and PA, as apparent from the test results described below. That is, as an antifreezing agent, it shows a quick effect and the effect lasts for a long time. In addition, the amount of ice melt can be obtained higher than CMAK as a whole. This is presumably because the ternary double salt CMPA has been given more energy than CMAK in its production.

In the compounding of raw materials for producing CMPA, CA:
The ratio of MA: PA is 4: 3: 3, which is the component ratio of the ternary double salt.
It is preferable to be closer to
If it is within 0%, it is possible to select a combination out of the equivalence relation. Preferred is within 30%. P
Based on A, 0.83 to 1.33: 1: 1
1.8: 0.6 to 1.4: 1, preferably 1.0
~ 1.7: 0.7 to 1.3: 1.

An advantage of CMPA over CMA is that, as also shown in the test results below, corrosion to aluminum, which cannot be avoided with CMA, is no longer seen with CMPA.

[0018]

EXAMPLES In the following examples, the performance and corrosivity of the antifreeze were tested as follows.

(Freezing point) Samples were 1%, 5%, 10%, 1%
Prepare a solution dissolved at a concentration of 5% or 20%.
Place 0 ml into test tube and freeze completely by cooling with dry ice. The mixture is left at room temperature, and when melting begins, it is observed with stirring with a thermometer, and the temperature at which the ice is completely melted is defined as the freezing point.

(Ice melting ability) After 500 ml of water was placed in a 500 ml polyethylene beaker, cooled to -5 ° C or -10 ° C and frozen, 10 g of the sample was sprayed on ice,
Leave in 5 ° C atmosphere for 10 minutes, 20 minutes, 30 minutes,
Measure the amount of ice melt after 60, 120 and 180 minutes.

(Anti-freezing ability) 12.7 g of a sample was
After dissolving in 20 g of the solution, put 20 g of the solution in a petri dish, place in a low-temperature constant temperature bath, leave at −5 ° C., −10 ° C., or −15 ° C., and freeze after 10 minutes, 30 minutes, 1 hour, and 3 hours. Observe the situation.

(Corrosiveness to Metal) ASTM F-4
Follow the method specified in 83. Using a 5% or 15% solution, the amount of increase or decrease in the surface of the aluminum, titanium or carbon steel specimen after 24 hours and 168 hours is measured.

The mixing Example 1 CA, the MA and PA at a ratio shown in Table 1 below, Table 1 CA: MA - PA Sample No. molar ratio Weight ratio 1 0.71: 0.49: 1.00 40%: 25%: 35% 2 0.89: 0.62: 1.00 43%: 27%: 30% 31.24: 1.38: 1.00 40%: 40%: 20 % Water was added to form a slurry that was partially dissolved and partially undissolved. The slurry was heated to evaporate to dryness, and the solid obtained by further heating to 180 ° C. was subjected to X-ray diffraction. The results are shown in FIG. 2 (No. 1), FIG. 3 (No. 2) and FIG. 4 (No. 3). In the same manner as above, a mixture of CA: MA = 1: 1 was used to evaporate the slurry to dryness and heat to synthesize CMA, and an X-ray diffraction chart was obtained. This is shown in FIG.

When comparing the chart of FIG. 1 with the charts of FIGS.
Both have clear differences, and FIGS. 2 to 4 show 2θ = 8.
Large peaks are observed around 2 °, 8.8 ° and 10.1 °, and peaks are observed around 26.1 °. Since this is different from any of the patterns of CA, MA, and PA, it is interpreted as a peak unique to CMPA. In particular, the chart of FIG. 3 has the largest difference from the chart of FIG. 2 is considered to be dominated by CMPA.

Example 2 K ₂ CO ₃ was added to an aqueous solution of CH ₃ COOH (abbreviated as “HA”), and PA + H
An aqueous solution of A was prepared. This aqueous solution was put into a stainless steel cylindrical reactor equipped with a rotating stirrer, and Ca (OH) ₂ and Mg (OH) ₂ were added thereto, and the same CA: MA: PA The reaction was performed by charging the mixture so as to obtain the ratio.

After the introduction of the hydroxide, the contents of the slurry reactor were gradually changed to those having a high solid content. The reaction product was dried by heating to 150 ° C. The dried aggregates are crushed by a crusher and sieved to 2 to 5 mm
Of the same size were collected. X-ray diffraction analysis of this product (referred to as sample No. 4) was as shown in FIG. 5, and a chart very similar to FIG. 2 was obtained.

Sample No. Table 2 shows the results of the freezing point test of No. 4. For comparison, known CMA and calcium chloride were also tested under the same conditions.

Table 2 Concentration (%) of the present invention No. 4 CMA calcium chloride 1 + 2 ° C + 3 ° C + 2 ° C 5 ± 0 ± 2 ± 0 10 -1 -1 -1 15 -3-2 -4 -20 -6 -2 -8

Sample No. FIG. 6 shows the test results of the ice melting ability of No. 4 at −5 ° C. From the graph of FIG. 6, it can be seen that the antifreezing agent of the present invention increases the amount of ice melt after a long period of time as compared with CMA, and has a long-lasting effect.

The antifreezing ability is as shown in Table 3. For comparison, CMA was also tested under the same conditions.

Table 3 Temperature 10 minutes 30 minutes 1 hour 3 hours Sample No. 4-5 ° C ○ ○ ○ △ -10 ○ ○ △ △ -15 ○ △ * △ △ CMA-5 -10 ○ ○ △ △ -15 ○ △ △ × Evaluation ○ Not frozen △ Partially frozen or sherbet Shape × frozen * soft sherbet shape

Table 4 shows the measurement results of the corrosiveness. Again, for comparison, CMA was tested under the same conditions.

Table 4 Sample time Aluminum Titanium Carbon steel (Time) 5% 15% 5% 15% 5% 15% No. 4 24 0.00 0.00 -0.004 -0.004 0.00 0.00 168 0.00 0.00 0.00 -0.001 0.00 0.00 CMA 24 +0.033 +0.030 -0.004 -0.003 -0.002 -0.002 168 +0.040 +0.040 0.00 -0.005 0.00 0.001 The unit is mg / mg. cm ² / 24hr

Example 3 Lightly burned dolomite was digested,
The molar ratio of Ca (OH) ₂ : Mg (OH) ₂ is 1.44: 1.0
0 digested dolomite was obtained. On the other hand, K ₂ CO ₃ is converted to CH ₃
A solution dissolved in a COOH aqueous solution and containing an excess of CH ₃ COOH was prepared.

A screw capable of transferring powder or slurry and a paddle for stirring were provided, and both were supplied to an extruder-type reactor capable of being heated by a jacket, and the paste was extruded in the form of a strand through a perforated plate. . The ratio of each component supplied to the reactor was Ca: Mg: K: HA =
0.89: 0.62: 1.00: 4.02. The warm strand was left to dry, crushed and sieved to a particle size of 2-5 mm.

With respect to the antifreezing agent thus obtained,
Ice melting tests at -5 ° C and -10 ° C were performed.
For comparison, the same test was carried out for the following cryoprotectants: CMA: commercial CMA, C: M = 3: 7 CMA75 + PA25: 75% by weight of the above CMA and PA2
Dolomite CMA75 + PA25 in a mixture with 5% by weight:
CMA obtained by reacting the above digested dolomite with acetic acid
Mixture of 75% by weight and 25% by weight of PA From the data in FIG. 7, the following can be seen. That is,
The addition of PA to CMA increases the ability to melt ice,
Dolomite CMA with an M / C ratio lower than 3/7, the optimum of CMA plus PA, has slightly lower performance, and the examples of the present invention show that (Mg source to dolomite Determining higher performance than CMA75 + PA25 (even though the ratio to Ca is not increased). The data in FIG. 8 show that at low temperatures of -10 ° C., CMA no longer serves much as a cryoprotectant, and that the cryoprotectant of the present invention performs best under these conditions. I have.

[0037]

According to the present invention, a novel compound in the form of a CA / MA / PA ternary double salt and a salt mixture containing the same as a main component and having a composition in the vicinity thereof are provided. These compositions are more durable than traditional CMA as antifreeze agents. Since the deicing agent of the present invention does not substantially corrode carbon steel and aluminum, when sprayed on roads and bridges, there is a fear that corrosion will occur on running automobile parts and various facilities in the vicinity. rare.

The method for producing the antifreezing agent of the present invention can be carried out in a conventional reactor, and can provide spherical particles or square particles depending on the application. The cost is low because dolomite, which is an inexpensive raw material, is used as a calcium and magnesium source, and it is not necessary to replenish magnesium from another source.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction chart of CMA synthesized from CA and MA.

FIG. 2 is an X-ray diffraction chart (C by molar ratio) of a substance (sample No. 1) obtained from a mixed slurry of CA, MA and PA.
A: MA: PA = 3.2: 2.2: 4.5).

FIG. 3 is an X-ray diffraction chart (C by molar ratio) of a substance (sample No. 2) obtained from a mixed slurry of CA, MA and PA.
A: MA: PA = 3.5: 2.5: 4.0).

FIG. 4 is an X-ray diffraction chart of a substance (sample No. 3) obtained from a mixed slurry of CA, MA and PA (C in terms of molar ratio)
A: MA: PA = 3.4: 3.8: 2.8).

FIG. 5: A substance obtained by adding Ca (OH) ₂ and Mg (OH) ₂ to an aqueous solution of PA and HA and reacting them (Sample No.
4) X-ray diffraction chart (molar ratio is the same as that of sample No. 2).

FIG. 6 shows data of one example of the antifreezing agent of the present invention in which its ice-melting ability was compared with that of a known antifreezing agent,
The graph which shows the time change of the amount of ice melt produced at -5 ° C.

FIG. 7 is a graph showing data of another example of the antifreezing agent of the present invention, in which the ice melting ability is compared with that of a known antifreezing agent, showing a time change of the amount of ice melt generated at −5 ° C.

FIG. 8 is a graph showing data of another example of the antifreezing agent of the present invention in which the ice melting ability is compared with that of a known antifreezing agent, showing a time change of the amount of ice melt generated at −10 ° C.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Seiji Muramoto 63-1, Ikuno, Katano-shi, Osaka Yoneyama Chemical Industry Co., Ltd. Osaka factory (56) References JP-A-62-267246 (JP, A) JP-A-6-279347 (JP, A) JP-A-6-279750 (JP, A) JP-A 9-13003 (JP, A) JP-A-1-502200 (JP, A) JP-A 5-508617 (JP, A) US Patent 5,219,483 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 53/10 C07C 51/41 C09K 3/00 102 C09K 3/18 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A ternary double salt represented by Ca ₄ Mg ₃ K ₃ (CH ₃ COO) ₁₇ . 2. An antifreezing agent comprising the ternary double salt of claim 1 as an active ingredient. 3. Antifreezing agent particles obtained by sizing the antifreezing agent according to claim 2 into particles suitable for mechanical spraying. 4. Ca (O) obtained by digesting lightly burned dolomite
The mixture of H) ₂ and _{Mg (OH) 2, CH 3} COOK and added to an aqueous solution prepared by dissolving approximately equivalent of CH ₃ COOH in the hydroxide, ternary claim 1 by reacting with stirring double salt , A paste containing the ternary double salt is dried and solidified, and the solidified product is crushed to produce a cryoprotectant particle.