JP2001115150A - Production method of antifreezing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an antifreezing agent excellent in quick-acting properties and persistence of effects, conveniently in a simple manner. SOLUTION: An antifreezing agent containing a calcium magnesium carboxylate and an antifreezing component acting more quickly than calcium acetate is produced by supplying a calcium magnesium component, an alkali or alkaline earth metal compound, and a carboxylic acid (especially acetic acid) to a tightly sealed reaction system 3 and reacting therein the above components while they are being kneaded and conveyed. The alkali or alkaline earth metal compound may be a carbonate, hydrogencarbonate, hydroxide, oxide, or the like, of an alkali metal or magnesium. The molar ratio of calcium to an alkali or alkaline earth metal in the antifreezing agent is about (5/95)-(40/60).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an antifreezing agent having a quick action and a long lasting effect.

[0002]

2. Description of the Related Art In a cold region, a car slip accident and accompanying traffic congestion are likely to occur due to snow accumulation, road surface freezing or freezing. As such a slip prevention measure, a medicine (antifreeze) is sprayed.

Conventionally, chlorides such as rock salt (sodium chloride) and calcium chloride are often used as antifreezing agents. However, the effect of using these chlorides to melt snow and ice has a quick effect but is not persistent, so that the antifreeze property cannot be maintained for a long time. If the drug is not persistent, it is necessary to repeatedly apply the drug, and a large amount of the drug is used in total. However, when a large amount of the chemical is sprayed, the metal used in automobiles and road facilities is corroded. In addition, by dissolving in water and flowing out, it causes death of plants, water pollution of groundwater, rivers and lakes, and the like.

Accordingly, calcium magnesium acetate (hereinafter, sometimes referred to as CMA) has been used as a deicing agent which is persistent, less corrosive, and has relatively little adverse effect on the environment. For example, Japanese Patent No. 2507504 discloses that CaMg ₂ (C ₂
H ₃ O ₂ ) ₆ are disclosed. However, CMA has low immediate efficacy.

[0005] For this reason, there is a demand for the development of an antifreezing agent which has a rapid effect and a long lasting effect, has a low corrosiveness and has a small adverse effect on the environment. For example, there is a demand for an anti-freezing agent that sprays snow before the commuting rush in the morning, melts the snow by the commuting rush, and maintains the snow-melting effect as it is until the evening homecoming rush.

[0006] Japanese Patent Application Laid-Open No. 11-5969 discloses a snow melting agent having both a slow effect (persistence) and a fast effect.
A composition comprising 5 to 40% of magnesium acetate (hereinafter sometimes referred to as MA) is added to calcium magnesium acetate. This composition is prepared by mixing and reacting a calcined dolomite powder and acetic acid with a kneader to produce CMA, mixing and reacting calcined magnesium carbonate and acetic acid with a kneader to produce MA, and blending the CMA and MA. It is obtained by doing. Further, this document states that the reaction of calcined dolomite is performed while cooling at room temperature to 100 ° C., that magnesium reacts slowly, and that CaO or MgO may be added during the reaction of dolomite. Has been described. However, in this method, a composition of CMA and MA cannot be easily obtained, resulting in an increase in cost.
In addition, in the production process of magnesium acetate, the magnesium acetate becomes clay-like (sticky), so that the reactivity is lowered. Further, since unreacted acetic acid is taken in, a strong acetic acid odor is generated, and the commercial value is lowered.

[0007] Japanese Patent Application Laid-Open No. 9-208955 discloses that calcium acetic acid is prepared by quantitatively supplying powdered and granulated dolomite and acetic acid, and reacting the powdered and granulated dolomite and acetic acid while kneading and transferring them in a closed reaction system. A method for making a magnesium composition is disclosed. This document describes calcium acetate (hereinafter sometimes referred to as CA).
It is described that a CMA composition containing a large amount of CA is preferable for preventing slip because of its low solubility in water. Further, in order to obtain a CMA composition containing CA, calcined dolomite and quicklime or slaked lime may be quantitatively supplied to the reaction system, and the ratio of calcined dolomite to quicklime or slaked lime is Ca / Mg = 1/1. It is described that it can be selected from a range of 3/1 (molar ratio).

[0008]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for easily producing an antifreezing agent which is excellent in quick action and sustainability.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an alkali or alkaline earth metal compound, a calcium magnesium component such as dolomite, and a carboxylic acid have a closed reaction. When the reaction is carried out while being transported together with the kneading in the system, the reaction between each metal component and acetic acid can be maintained at a high level by effectively utilizing the heat of reaction, and calcium magnesium carboxylate and freezing more quickly than calcium acetate can be easily obtained. The present inventors have found that an antifreezing agent having an antifreeze component can be obtained and completed the present invention.

That is, in the present invention, a calcium magnesium component, an alkali or alkaline earth metal compound, and a carboxylic acid (particularly, acetic acid) are supplied to a closed reaction system, and the components are reacted while being kneaded and transferred. By doing so, an antifreeze containing calcium magnesium carboxylate and an antifreeze component that is more effective than calcium acetate is produced. The alkali or alkaline earth metal compound may be an alkali metal or magnesium carbonate, hydrogen carbonate, hydroxide, oxide or the like. The ratio of calcium and alkali or alkaline earth metal in the antifreeze is, for example, 5/95 to 40/60 (molar ratio).
Degree. The ratio of acetic acid may be about 0.8 to 1.2 times the stoichiometric amount based on the total of the calcium magnesium component and the alkali or alkaline earth metal compound. The calcium magnesium component and the alkali or alkaline earth metal compound may be quantitatively supplied to the closed reaction system, respectively, and are reacted at a temperature of 80 to 130 ° C. while being transported together with kneading, and are produced with the reaction. The antifreezing agent may be manufactured continuously by condensing the evaporation component and returning at least a part of the condensed liquid to the kneading system.

[0011]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a calcium magnesium component, an alkali or alkaline earth metal compound,
React with carboxylic acid. As the calcium magnesium component, for example, calcium and magnesium,
Calcium / magnesium = 30 / 70-70 / 30
(Molar ratio), preferably 40/60 to 65/35
(Molar ratio). Preferred calcium magnesium components include dolomite. The calcium magnesium component is usually calcined (for example, calcined dolomite or the like) in order to increase the reactivity to the carboxylic acid.

Among the metal components constituting the alkali or alkaline earth metal compound, examples of the alkali metal include lithium, sodium and potassium. Examples of the alkaline earth metal include magnesium and barium. Preferred metal components include alkali metals and magnesium, especially alkali metals (sodium, potassium, etc.).

As the alkali or alkaline earth metal compound, carbonates (sodium carbonate, potassium carbonate, magnesium carbonate, etc.), hydrogen carbonates (sodium hydrogen carbonate,
Examples thereof include potassium hydrogen carbonate and the like, hydroxides (such as sodium hydroxide, potassium hydroxide and magnesium hydroxide), and oxides (such as magnesium oxide).

The solid components such as the calcium magnesium component and the alkali or alkaline earth metal compound may be granulated as required. The average particle size of the powder is, for example, about 0.01 to 5 mm, preferably 0.05 to 3 mm.
mm.

Examples of the carboxylic acid include C _1-5 carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid and valeric acid. Preferred carboxylic acids are C _1-3 carboxylic acids, especially formic acid and acetic acid.

The carboxylic acid does not need to contain much water like glacial acetic acid, but may be an aqueous carboxylic acid solution if necessary. The carboxylic acid concentration in the aqueous solution is, for example, about 50 to 99.5% by weight, preferably 7
It can be selected from the range of about 0 to 99.5% by weight.

In the present invention, the calcium magnesium component, an alkali or alkaline earth metal compound,
And the carboxylic acid are supplied to the closed reaction system (particularly, quantitatively supplied), and reacted while being transferred together with kneading, whereby calcium magnesium carboxylate and an alkali or alkaline earth metal having a higher effect than calcium acetate are obtained. (Particularly, metal components other than calcium such as sodium, potassium and magnesium) and a carboxylate can be obtained. Calcium magnesium carboxylate can maintain the snow-melting effect over a long period of time, and alkali or alkaline earth metal carboxylate can quickly melt ice and snow, so that an antifreezing agent with excellent durability and quick-acting properties can be obtained. Can be.

When the calcium magnesium carboxylate and the alkali or alkaline earth metal carboxylate are produced by such a method, the reaction is carried out together with the kneading in a closed reaction system, so that the reaction heat is effectively utilized. It is possible to maintain high reactivity between an alkali or alkaline earth metal (sodium, potassium, magnesium, etc.) and acetic acid, and to easily obtain an antifreezing agent. In addition, it can be manufactured with one reaction device, and is excellent in device efficiency. Furthermore, even if the alkali or alkaline earth metal carboxylate is a compound that easily becomes clay-like (mochi), such as magnesium acetate, coking with calcium magnesium carboxylate can prevent clay formation. And acetic acid odor can be suppressed.

When the antifreezing agent is produced by a closed reaction system, it can be produced, for example, by using the same apparatus as disclosed in Japanese Patent Application Laid-Open No. 9-208955 shown in FIG. That is, the calcium magnesium component and the alkali or alkaline earth metal component are preliminarily mixed, and the mixture is passed through a hopper 1 and a fixed-quantity feeder 2 to a single-shaft or twin-shaft kneader (mixer) 3 constituting a closed reaction system. To the unit quantitatively and continuously. On the other hand, the carboxylic acid is quantitatively and continuously supplied from the supply ports 4a to 4c branched from the supply line 5. Each component supplied to the kneading machine 3 reacts by rotating the spiral stirring blade (screw) in the axial direction, while kneading from the starting end to the rear end of the kneading machine and transferring. The reaction mixture transferred to the rear end of the kneader can be extruded quantitatively by rotating a screw. In addition, since it is kneaded in a closed-type reactor, it is possible to prevent the powder and granules from adhering to the apparatus, and it is possible to increase the yield by smooth operation. Furthermore, since the reaction system is a closed type, there is no problem such as scattering of dust, and the working environment can be improved.

The supply of the calcium magnesium component and the alkali or alkaline earth metal compound from the quantitative feeder 2 and the supply of the carboxylic acid from the supply line 5 are performed quantitatively and continuously. That is, it is generally difficult to quantitatively supply a solid (for example, a granular material) as compared with the quantitative supply of a liquid such as a carboxylic acid. It is difficult to perform evenly. Therefore, in the present invention, it is important to supply the solid and acetic acid quantitatively and continuously.

The ratio of the calcium magnesium component to the alkali or alkaline earth metal compound may be in a range in which the product has a fast-acting and long-lasting antifreeze, for example,
The ratio of calcium in the antifreeze to alkali or alkaline earth metal other than calcium (sodium, potassium, magnesium, etc.) is the former / the latter = 15 / 85-
About 50/50 (molar ratio), preferably 20/80 to 5
The calcium magnesium component and the alkali or alkaline earth metal compound are mixed so as to be about 0/50 (molar ratio). When the alkali or alkaline earth metal is magnesium, the ratio between calcium and magnesium may be about 20/80 to 45/55 (molar ratio).

When an alkali metal compound is used, the ratio between the calcium magnesium component and the alkali metal compound is the former / the latter = about 10/90 to 90/10 (weight ratio), preferably 20/80 to 80/20 (weight). Ratio), more preferably about 30/70 to 70/30 (weight ratio).

In order to obtain an antifreezing agent which is particularly excellent in immediate action, an alkali or alkaline earth metal compound may be used in an amount larger than the above ratio. When it is obtained, the calcium magnesium component may be higher than the above ratio. By appropriately adjusting the ratio between the calcium magnesium component and the alkali or alkaline earth metal compound, the balance between the rapid effect and the sustainability can be easily adjusted.

When the calcium magnesium component and the alkali or alkaline earth metal component are supplied, they may be supplied to the respective reaction systems without being mixed in advance.
For example, a plurality of powder supply ports each having a hopper and a feeder may be independently provided, and a calcium magnesium component may be supplied from one supply port, and an alkali or alkaline earth metal component may be supplied from the other supply port.

The ratio of acetic acid is about 0.8 to 1.2 times, preferably about 0.8 to 1.0 times the stoichiometric amount based on the total of the calcium magnesium component and the alkali or alkaline earth metal compound. More preferably 0.85-
0.95 equivalent. In addition, the supply rate of acetic acid can be selected according to the purity and supply rate of the calcium magnesium component and the alkali or alkaline earth metal compound. Acetic acid does not need to be supplied at a plurality of points in the mixing system, and may be supplied from only one point of the kneader, for example, only from the start end.

In the present invention, the reaction is performed at a relatively high temperature by effectively utilizing the reaction heat for heating the reaction system. The reaction temperature is, for example, about 80 to 130 ° C, preferably about 90 to 120 ° C, and more preferably about 90 to 110 ° C. When the reaction temperature is out of the above range, the temperature may be controlled by a jacket.

Further, according to the present invention, even a component having low reactivity such as a magnesium component is reacted while kneading and transferring at a relatively high temperature in a closed system, so that it can be reacted quickly. The average residence time (reaction time) of the kneaded material in the kneader is, for example, about 0.1 to 30 minutes, preferably 1 to 20 minutes, and more preferably about 1 to 10 minutes.

In the single-screw or twin-screw kneader, the rotation speed of the screw can be selected according to the transfer speed of the kneaded material, the extruded amount, and the like, and may be, for example, about 10 to 100 rpm.

Evaporated components (such as water and unreacted carboxylic acid) from the reaction system are condensed in at least one condenser (heat exchanger) 6a, 6b connected to the kneading system 3.
Return to kneading system. For this reason, even if it is a closed type, large reaction heat can be effectively removed by latent heat of evaporation and condensation, and the condensate can be returned to the reaction system by the circulation system, thereby maintaining the mass balance of the reaction system. Further, the distilling of the liquid component can be prevented, and the uniformity of the kneading system can be improved. For example,
When the carboxylic acid from the reaction system is condensed and returned to the kneading system, not only can the loss of the carboxylic acid be prevented, but also a uniform and smooth mixing and reaction can be maintained, and a metal component having low reactivity such as magnesium is used. Can also be efficiently reacted with a carboxylic acid. In addition, as a general method, even if an attempt is made to remove heat by flowing a refrigerant through a jacket provided in a reactor, since the reaction system is a solid phase reaction between powder and granules and acetic acid, the reaction heat is efficiently removed. It is difficult. And if heat removal efficiency falls, the uniformity of quality of the product antifreeze will fall.

Both ends of the condensers 6a and 6b of the kneading machine 3 may be respectively partitioned by material seals provided with partitioning members.
A holding member may be provided at the location where b is provided to form an upper space that serves as a passage for the evaporated component by holding the component to be kneaded. When the reaction is performed while suppressing the components to be kneaded, not only can the evaporated components be smoothly refluxed, but also the pressure can be applied to the kneading system, and the reactivity of the metal components can be increased. When a plurality of capacitors are used, it is not necessary to press the components to be kneaded by the pressing member between the capacitors in the kneading machine, and the raw material charging port side of the most upstream condenser and the discharge port side of the most downstream condenser are not necessary. A pressing member may be provided to press the component to be kneaded at the site.

It is not always necessary to condense the evaporated components with a condenser directly connected to the kneading system.
The condenser may be connected to the kneader via a return line, and the condensed liquid may be returned to the closed reaction system through the return line.

The condensed liquid condensed by the condenser only needs to return at least a part thereof (particularly, carboxylic acid as a reaction component) to the reaction system, and non-reactive components (moisture, etc.) do not necessarily return to the reaction system. There is no.

The reaction mixture thus obtained may be extruded from the rear end of the kneader 3 and granulated by the granulator 9. When granulating by the granulator 9, water can be supplied from the water supply line 8 and the water supply port 7 at the rear end side of the kneading machine 3 (in this example, downstream of the condenser) to perform granulation. It may be a water-containing composition. In addition, when granulating by adding water, it is sufficient to prepare a water-containing composition that can be granulated at least in the granulating step by the granulator 9. That is, (1) water is added in any one of a kneading step in a kneader or a kneading step accompanying compression extrusion in a granulator, and a granulated water-containing composition is prepared by mixing or kneading, Extrusion granulation may be carried out by a granulator. (2) In both steps, that is, while adding a part of water (for example, a small amount of water) to the kneader 3, a predetermined amount of the extruded reaction product is further added. Water may be added to prepare a water-containing composition capable of granulation, and the composition may be extruded and granulated by a granulator.

The amount of water supplied is, for example, 0 to 20 parts by weight (for example, 3 to 2 parts by weight) based on 100 parts by weight of the total of the calcium magnesium component and the alkali or alkaline earth metal.
0 parts by weight), preferably 0 to 15 parts by weight (for example, 4 to
15 parts by weight), and 0 to 10 parts by weight (for example, 5 parts by weight).
-10 parts by weight). When a carboxylic acid aqueous solution is used, the amount of the water to be added includes the content of water in the carboxylic acid aqueous solution.

The aqueous composition extruded from the kneader can be granulated by a granulator 9 and dried to produce a product. In the example shown in the figure, the water-containing composition is extruded into a thread-like (or noodle-like) shape by a granulator (extrusion molding machine) 9, and the extruded product is conveyed by a cooling conveyor 10 while being sucked. The water is removed (dried) while sucking the water evaporating by the hood 11 and is cooled. That is, a conveying means is used as a means for cooling and drying the extruded product. Extrusion in the form of a thread can increase the granulation efficiency.

When the above water-containing composition having a low water content is extruded from a kneader at a temperature of about 80 to 120 ° C. (eg, 90 to 110 ° C.), the addition of the kneader can be greatly reduced and the granulator 9 can be used. 70 to 120 ° C (for example, 75 to
When extruding in the form of a thread (or noodles or flakes) at about 110 ° C., the extruded water-containing composition is cooled (for example, 10 to 50) in the subsequent transportation process without a drying step.
C, preferably about 20 to 40 C). For this reason, in this example, a noodle-like formed body that is dried while being cooled in the process of being conveyed by the conveyor 10 is supplied to the sizing machine 12, and the noodle-shaped molded product is cut by a rotary cutter in the sizing machine, and the granulated or pellet-shaped product is cut. Products.

The granulation and extrusion of the water-containing composition may be carried out by a conventional method, for example, a method using a pressure extruder (compression extruder).

In the case of supplying a thread-like compact to the granulator 12 having a rotary cutter, in order to increase production efficiency, 30
It is advantageous to supply a thread-shaped molded product cooled to about 50 ° C. and cut it continuously by a rotary cutter. The rotation speed of the cutter can be selected according to the desired pellet size and the supply amount of the formed body, for example, 1000 to 3000 r.
pm, preferably about 1500 to 2500 rpm in many cases.

In the production method of the present invention, granulation, extrusion molding and sizing with addition of water are not always necessary. For example, the antifreezing agent may be directly taken out from the rear end of the kneading machine 3 without installing the granulator 9. In particular, when the reaction is performed while removing non-reacted components (such as water) from the reaction system, the water content of the reaction mixture is small.
By directly taking out from the rear end, a powdery antifreezing agent having high fluidity (free flowing) can be obtained.

In the above-mentioned manufacturing method, a drying step is not particularly employed. However, if necessary, the granulated material may be dried by a granulator and then supplied to the granulator, and the dried granulated material may be dried. The granulator may be pulverized, sieved through a sieve having a predetermined mesh size or the like, and sized to produce a product.

The antifreezing agent may contain various additives as required, for example, friction aids (for example, inert granules such as sand, pulverized lime, vermiculite, pumice, wood flour, fruit husk, etc.) ), A black substance (for example, a black colorant such as charcoal or carbon black).

According to the present invention, a calcium magnesium component, an alkali or alkaline earth metal compound, and a carboxylic acid can be efficiently reacted, and a quick-acting and long-lasting deicing agent can be continuously and easily prepared. Can be manufactured.

The antifreeze thus obtained can be used for a wide range of applications. That is, the conventional anti-freezing agent is excellent in only one of the properties of fast-acting or long-lasting, so that the spraying period (spraying before road freezing where sustainability is important (pre-spraying) and quick-acting) are important. To be used according to road conditions (such as snowy roads where sustainability is important, frozen roads where quick action is important), regional characteristics, and weather characteristics. The antifreezing agent obtained according to the present invention can be used for a wide range of applications regardless of these situations.

Since this antifreezing agent has an excellent ability to melt ice and snow, it can be used as a snow melting agent (snow removing agent, deicing agent). Furthermore, it is also useful as an anti-slip agent that can shorten the braking distance of a traveling vehicle by spraying on a frozen surface, a snow surface, an ice surface, or the like. The amount of the antifreeze agent (snow-melting agent, anti-slip agent)
It can be selected according to the temperature, the amount of snow, the degree of freezing, the purpose of spraying (anti-freezing, snow-melting, anti-slip), etc.
500 g / m ^2, preferably from 5 to 250 g / m ^2, more preferably 10 to 100 g / m ² approximately.

[0045]

According to the present invention, since the calcium magnesium component, the alkali or alkaline earth metal compound, and the carboxylic acid are reacted while being kneaded and transported in a closed reaction system, the heat of reaction is effectively utilized. Thus, an antifreezing agent having excellent fast-acting and long-lasting properties can be easily obtained.

[0046]

The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the examples, the weight of acetic acid means the weight in terms of glacial acetic acid.

Embodiment 1 The downstream condenser 6b and the downstream acetic acid supply line 4
The same apparatus as that in FIG. 1 was used except that b and 4c were not provided. Mixture of calcined dolomite and anhydrous sodium carbonate (calcined dolomite / anhydrous sodium carbonate = 68 /
32 (weight ratio); calcium / (magnesium + sodium) = 42/59 (molar ratio)) from the quantitative feeder 2 to the twin-screw continuous kneader 3 (100 mmφ × 1000 mm,
It was supplied at a supply rate of 20 kg / hr at a rotation speed of 30 rpm. For the mixture kneaded and transferred by the kneading machine 3,
36 kg / hr of acetic acid supplied from acetic acid supply line 4a
(Using a plunger pump) to react. Tap water (cooling water) is passed through the spiral condenser 6a (heat transfer area: 0.3 m ² ) to condense evaporation components (acetic acid, water, etc.) generated from the reaction mixture in the kneader and return to the reaction system. Was. Water is added to the reaction mixture transferred to the rear end of the kneader 3 from the water supply port 8 at a supply amount of 6 kg / hr to obtain a water-containing composition (temperature of 105 ° C., powdery ), And continuously extruded from the kneader 3 to obtain a mixture of CMA and sodium acetate. The temperature of the composition at the outlet of the kneader was 105 ° C., and the composition was partly in the form of granular powder. The power required for kneading during the continuous operation (that is, during the operation at a charged amount of 62 kg / hr) was about 4 A with respect to a 1.5 kW rated motor, and the operation was smooth.

Example 2 From the quantitative feeder 2, a mixture of calcined dolomite and anhydrous sodium carbonate (calcined dolomite / anhydrous sodium carbonate = 40/60 (weight ratio); calcium / (magnesium + sodium) = 25/75 (molar ratio) )) To supply 2
Example 1 except that the acetic acid was supplied at a supply rate of 35.6 kg / hr from the acetic acid supply line 4a at a supply rate of 5 kg / hr.
Same as. The reaction was smoothly performed without any problem.

Example 3 From the quantitative feeder 2, a mixture of calcined dolomite and potassium carbonate (calcined dolomite / potassium carbonate = 67/3)
3 (weight ratio); calcium / (magnesium + potassium) = 44/56 (molar ratio)) 25 kg / hr
And supply acetic acid from the acetic acid supply line 4a at 43k.
The procedure was the same as in Example 1, except that g / hr was supplied. The reaction was smoothly performed without any problem.

Example 4 A water-containing composition obtained in the same manner as in Example 1 was dried while naturally cooling to 80 ° C. This composition is formed into a thread (noodle) having a diameter of 3 mmφ by compression extrusion, then dried while being naturally cooled to about 40 ° C., and sized at 1400 to 2,000 rpm using a sizing machine having a rotary blade. By granulating, a granulated product containing 95% by weight or more of pellets having a shape larger than 4 mmφ × 2 mm was obtained.

Example 5 In the same manner as in Example 4, extruded into a yarn (noodle) having a diameter of 8 mmφ, dried while cooling naturally, and pulverized with a roll crusher to obtain a pellet having a particle size larger than 3 mm. Was obtained in an amount of 68% by weight or more.

Example 6 A composition (particle size: 150 μm to 1 mm) containing CMA and sodium acetate obtained in the same manner as in Example 2 was applied at a pressure of 5
It was supplied to a compression roll of 〜9 t at a supply amount of 50 to 90 kg / hr, and was compression-molded into a plate shape. By continuously supplying the plate-like molded product to the crusher, a granulated product containing a granulated product having a particle size larger than 0.5 mm by about 80% by weight was obtained.

Embodiment 7 The condenser 6b on the downstream side and the acetic acid supply line 4 in the central part
The same apparatus as in FIG. 1 was used except that b was not provided. Mixture of calcined dolomite and anhydrous sodium carbonate (calcined dolomite / anhydrous sodium carbonate = 68/32)
(Weight ratio; calcium / (magnesium + sodium) = 32/68 (molar ratio)) is supplied from the quantitative feeder 2 to the twin-screw continuous kneader 3 (100 mmφ × 1000 mm, rotation speed 30 rpm) at a supply amount of 20 kg / hr. did.
Acetic acid is supplied from the acetic acid supply lines 4a and 4c to the mixture which is kneaded and transferred by the kneader 3 at an amount of 36 kg / h.
r (using a plunger pump) to react.
Thereafter, the same operation as in Example 1 was performed to obtain a mixture of CMA and sodium acetate. The power required for kneading during the continuous operation (that is, during the operation at a charged amount of 62 kg / hr) is the same as in Example 1 (current about 4 A for a motor of rated 1.5 kW), and the operation is smooth. did it.

The quick-acting and sustaining properties of the antifreezes obtained in Examples 1 to 3 were examined as follows. For comparison, cases where CMA, calcium chloride dihydrate, and sodium chloride were used as antifreezing agents were also examined (Comparative Examples 1 to 3).

[Rapid effect] In a petri dish (86 mmφ),
60 g of distilled water was frozen, and after freezing, it was kept at −5 ° C. for about 1 hour to produce ice. 2 g of an antifreeze was evenly sprayed on ice in a petri dish and maintained at -5 ° C. One hour after spraying the antifreeze, the weight of the melted water (the amount of ice melt) was measured.

[Persistence] The antifreeze was sprayed in the same manner as described above, and the amount of ice melt after 4 hours, 6 hours and 12 hours was examined.

The results are shown in Tables 1 and 2.

[0059]

[Table 1]

[0060]

[Table 2]

As is clear from Table 1, the antifreezes of Examples 1 to 3 can melt more ice than CMA in a short time, and are excellent in quick action.

As is clear from Table 2, the amount of ice melt decreased with calcium chloride dihydrate 4 hours after spraying.
With sodium chloride, the amount of ice melt has decreased after 6 hours from the application. That is, in these antifreezing agents, the ice once melted is re-frozen, and the durability is low. In contrast,
The antifreezing agents of Examples 1 to 5 have a constant amount of ice melt over a long period of time and are excellent in persistence.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a manufacturing method of the present invention.

[Explanation of symbols]

 3: Closed reaction system

Claims (7)

[Claims] 1. A calcium magnesium component, an alkali or alkaline earth metal compound, and a carboxylic acid are supplied to a closed reaction system, and the components are reacted while being kneaded and transported.
A method for producing a cryoprotectant containing a cryoprotectant component that is more effective than calcium acetate. 2. The method according to claim 1, wherein the alkali or alkaline earth metal compound is a carbonate, hydrogencarbonate, hydroxide or oxide of at least one metal selected from alkali metals and magnesium. 3. The method according to claim 1, wherein the carboxylic acid is a C _1-5 carboxylic acid. 4. The method according to claim 1, wherein the ratio of calcium in the deicing agent to alkali or alkaline earth metal is 15/85 to 50/50.
The production method according to claim 1, wherein the calcium magnesium component and the alkali or alkaline earth metal compound are mixed so as to be 50 (molar ratio). 5. The method according to claim 1, wherein the ratio of the carboxylic acid is 0.8 to 1.2 times the stoichiometric amount based on the total amount of the calcium magnesium component and the alkali or alkaline earth metal compound. 6. A calcium-magnesium component and an alkali or alkaline earth metal compound are quantitatively supplied to a closed reaction system, and the mixture is heated at a temperature of 8 while being transferred together with kneading.
The antifreezing agent is continuously produced by reacting at 0 to 130 ° C., condensing an evaporating component generated by the reaction, and returning at least a part of the condensate to the kneading system.
5. The production method according to any one of the above items 5. 7. The method according to claim 6, wherein the carboxylic acid is returned to the kneading system.