JP2015155520A - Freezing-point depressant and method for utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing-point depressant which does not contain a component which becomes a problem in terms of toxicity and environmental loads and can be used safely, is inexpensive, and has a high antifreeze effect and an effective antirust effect, and to provide a method to utilize the same.

SOLUTION: The freezing-point depressant comprises a succinate or a propionate. The succinate is disodium succinate or disodium succinate hexahydrate. The propionate is sodium propionate. The method for utilizing the freezing-point depressant includes mixing at least one selected from sodium chloride, calcium chloride, and magnesium chloride, and the freezing-point depressant to provide a road surface antifreezing agent, which is scattered on a frozen road surface in a cold district.

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to a freezing point depressant that prevents freezing of water and a method of using the freezing point depressant.

  Conventionally, there are various types of freezing point depressants that cause freezing point depression and prevent water from freezing, and various substances are used. There are many ways to use freezing point depressants, for example, antifreeze that is dissolved in a solvent to be used as cooling water or heat medium for engines and air conditioning, or a road surface that is sprinkled and sprayed onto a frozen road surface in a snowy and cold region to melt ice and snow on the road surface. It is used for anti-freezing agents. The road surface antifreezing agent dissolves in water on the road surface to lower the freezing point, thereby lowering the freezing temperature of the water on the road surface. Road surface anti-freezing agents include chlorides such as calcium chloride, sodium chloride and magnesium chloride, urea, CMA (based on calcium acetate and magnesium acetate) and KAC (based on potassium acetate solution) Acetates such as are sold. Of these, mainly chlorides such as calcium chloride, sodium chloride and magnesium chloride are most widely used in Japan. These chlorides have a low freezing temperature (magnesium chloride -32 ° C, calcium chloride -54 ° C, sodium chloride -22 ° C), excellent solubility and immediate effect, long-lasting effects, and low price It becomes an effective road surface anti-freezing agent because of its abundant amount, easy storage, transportation and spraying, and is highly practical. However, chloride causes salt damage, and there are problems such as corrosion of metals, deterioration of concrete, and contamination of surrounding soil. For example, there are damages such as car bodies corroding, structures around roads such as bridges, road signs, and tunnels being deteriorated and damaged, and roadside trees withering.

  Various measures have been considered to solve this problem. For example, it is considered that urea, sodium formate, sodium acetate or the like is used as a road surface anti-freezing agent as a substitute for chloride. In any case of urea, sodium formate, and sodium acetate, the solid (100% antifreezing agent) or high-concentration aqueous solution is sprayed on the frozen road surface to be used for release of freezing or prevention of freezing.

In addition, as a road surface anti-freezing agent devised to suppress salt damage, the anti-icing agent of Patent Document 1 includes 30 to 70% sodium formate, 30 to 70% sodium chloride, and a corrosion preservative (eg, metasilicate). It is contained at 0.1 to 3% by weight. The rust inhibitor component is sodium metasilicate, and the SiO ₂ / Na ₂ O ratio is 0.95 to 0.97. The method of use is to form into solid particles having a diameter of 0.3 to 10 mm, or to spray on a frozen road surface as a 5 to 25 wt% aqueous solution.

  Moreover, the antifreezing agent of patent document 2 is based on urea and 28-66 weight% sodium chloride with respect to urea as a main component. The method of use is to form an aqueous solution and spray on a frozen road surface.

  The antifreezing agent of Patent Document 3 is composed of a solution containing sodium formate, ammonium formate, and glycol. The method of use is to spray the frozen road surface with a watering machine.

  The antifreezing agent of Patent Document 4 contains 0.001 to 20 weights of a water-soluble polymer in 100 parts by weight of a mixture of a carboxylic acid salt having 1 to 10 carbon atoms and a water-soluble polyhydric alcohol having 1 to 6 carbon atoms. And 0.001 to 20 parts by weight of one inorganic substance selected from silica gel, alumina gel, sodium silicate and potassium silicate. The method of use is to form an aqueous solution and spray on a frozen road surface.

  The road antifreezing agent of Patent Document 5 is composed of a porous aggregate having an average particle diameter of 0.6 to 13.2 mm and impregnated with acetate and a rust inhibitor. Sodium acetate, potassium acetate, calcium acetate and the like are used as the acetate, and sodium nitrite, sodium tripolyphosphate and the like are used as the rust inhibitor. The method of use is to spray directly on a frozen road surface.

  The antifreezing agent of Patent Document 6 is obtained by coating a predetermined amount of a predetermined antirust agent on the surface of granular or powdered sodium chloride. The rust preventive agent is any of sodium silicate, sodium pyrophosphate, lignin sulfonic acid, and sodium nitrite. The method of use is to spray directly on a frozen road surface.

JP 2000-109820 A Japanese Patent No. 3020915 Japanese Patent No. 3764475 JP-A-10-251622 JP-A-10-140130 JP 2002-60726 A

  The antifreezing agents for suppressing salt damage of each background art may cause new problems in terms of toxicity, environmental load, cost, and the like. Urea, sodium formate, sodium acetate, and the like, which are non-chlorides, have the advantage that they are less likely to cause corrosion of metal structures, but have the disadvantage of being more expensive than chlorides. In addition, sodium acetate has a problem that bad odor is generated, and is not suitable for use as a wide range of road surface anti-freezing agent. Such non-chlorides are organic acids (urea) or salts (sodium salt, potassium salt or calcium salt) of organic acids (formic acid, acetic acid, etc.), and the aqueous solution is BOD (biochemical oxygen derived from organic components). (Required amount) and COD (chemical oxygen demand) are present in a certain amount, and may be regulated by water-related laws and regulations and local ordinances.

  In the case of Patent Document 1, Patent Document 3, Patent Document 4, and Patent Document 5, since an organic acid salt is used, there is a problem of BOD and COD derived from organic components as described above. In the case of Patent Document 2, since urea is included, there is a problem that the soil around the road is enriched by nitrogen in the urea. Furthermore, in the case of Patent Document 3, since sodium formate is the main component and there is an increase in hydrogen ion concentration (pH 8.5) during storage of the solution, it is necessary to control the pH by adding subcomponents, which is troublesome. It is such a thing. In the case of Patent Document 4, the anti-freezing agent made of chloride is made to improve the point that the durability is not good and the anti-slip effect is not sufficient, and the anti-rust effect. It does not have. In the case of Patent Document 5, a step of filling the pores of the aggregate with acetate is necessary, and in the case of Patent Document 6, a step of coating the surface of sodium chloride with a rust inhibitor is necessary. And costly.

  In addition, as a solution to the metal corrosion problem, it has been proposed to use various surfactants as a rust inhibitor, but in general, the combined use of surfactants is expensive and has the effect of preventing freezing. In addition, other problems such as slipperiness and pollution caused by surfactants may occur, and this has not been put into practical use.

  The road surface anti-freezing agent must take into consideration the impact on the road and the environment around the road, and it is required to have an inexpensive and effective anti-rust effect and to be able to utilize the existing spraying system. In order to satisfy the requirements, the composition of the conventional road surface antifreezing agent alone is insufficient, and a new one is required.

  The present invention has been made in view of the problems of the background art described above, and can be used safely without including components that are problematic in terms of toxicity and environmental load, is inexpensive, has a high anti-freezing effect, and is effective. It aims at providing the freezing point depressant which has a rust prevention effect, and its utilization method.

  The present invention is a freezing point depressant characterized by containing a succinate or a propionate. The succinate is disodium succinate or disodium succinate hexahydrate. The propionate is sodium propionate.

  It contains the succinate or propionic acid and glycerin. The glycerin is preferably mixed at a concentration of 5 to 20%.

  In the present invention, at least one chloride selected from sodium chloride, calcium chloride and magnesium chloride and the freezing point depressant are mixed to form a road surface anti-freezing agent, which is sprayed on the road surface of a frozen road in a cold region. This is a method of using a freezing point depressant.

  The mixing ratio of the road surface antifreezing agent is 5 to 20 parts by mass of disodium succinate, disodium succinate / hexahydrate or sodium propionate with respect to 100 parts by mass of the chloride.

  It is preferable to use glycerin mixed with the disodium succinate, the disodium succinate hexahydrate, or the sodium propionate.

  The present invention is a freezing point depressant that can be used safely without containing components that cause problems with toxicity and environmental load, and can reliably lower the freezing point of an aqueous solution. In addition, salt damage is not caused, and rusting of metals and deterioration of concrete can be greatly suppressed. Furthermore, handling is easy and it can utilize for various uses, such as a road surface antifreezing agent and the heat medium of an electric heating system. Moreover, it can be produced by fermentation from raw materials such as plants, and since it is a plant-derived component, it is environmentally friendly and can promote the use of the bio industry.

It is a graph which shows the change of the freezing point of the aqueous solution which changed the density | concentration of glycerol in the range of 0-25%, and dissolved sodium chloride. It is the graph which measured the change of the freezing point when mixing sodium propionate, disodium succinate, and disodium succinate hexahydrate at a concentration of 20% in a glycerin 10% aqueous solution.

  Embodiments of the present invention will be described below. The freezing point depressant according to this embodiment includes any of disodium succinate, disodium succinate hexahydrate, and sodium propionate. Disodium succinate, disodium succinate hexahydrate, and sodium propionate can be produced by fermentation from raw materials such as plants. It is a plant-derived component and does not contain any components that cause problems with toxicity or environmental impact and is safe. In particular, disodium succinate and sodium propionate are highly safe compounds used as food additives. It is safe and odorless, free from ingredients that cause problems with toxicity and environmental impact.

  The freezing point of disodium succinate is -11.6 ° C, the freezing point of disodium succinate hexahydrate is -5.9 ° C, and the freezing point of sodium propionate is -17 ° C. Since the freezing point depressant of this embodiment is solid at room temperature and water-soluble, it can be handled as a solid or an aqueous solution.

  Next, a method for using the freezing point depressant of this embodiment will be described. For example, it is used as a road surface anti-freezing agent that melts ice and snow, and is sprayed on a road surface frozen in a snowy and cold region to lower the freezing point and melt the ice and snow on the road surface. As the road surface antifreezing agent, the freezing point depressant may be used alone, or may be mixed with one or a plurality of chlorides selected from chlorides such as sodium chloride, calcium chloride and magnesium chloride.

  When mixed with chloride, the mixing ratio is suitably 5 to 20 parts by mass of disodium succinate, disodium succinate / hexahydrate or sodium propionate with respect to 100 parts by mass of chloride. is there. As a method of mixing with chloride, for example, once a solid agent or aqueous solution of chloride is prepared, a predetermined amount of the freezing point depressant is added thereto to obtain a road surface antifreeze agent. Disodium succinate (pH 8.9) and sodium propionate (pH 7.7) are weakly alkaline aqueous solutions, but the road surface anti-freezing agent to which this is added is easy to control the pH, and is compatible with water quality regulations. Adjust within the range. The road surface anti-freezing agent sprayed on the road surface will eventually flow into the public water area along with the melted ice and snow, so the pH is preferably 9.0 or less due to the regulations of water quality laws and regulations. In order to protect the device, it is desirable to use a weak alkaline region. In addition, although the road surface antifreezing agent made of chloride alone causes salt damage, the salt damage is suppressed by mixing with the freezing point depressant.

  Moreover, since the road has an inclination (about 2-3%) and flows out even if the antifreezing agent is sprayed, it is necessary to fix it on the road. Therefore, it is preferable to mix glycerin as a fixing agent. This is because glycerin is odorless, highly safe, and highly sticky. By mixing glycerin with the freezing point depressant of this embodiment, in addition to the above effects, it has high fixability.

  According to the freezing point depressant of this embodiment, the following various effects are obtained. First, it can be used safely without containing components that are problematic in terms of toxicity and environmental load, and the freezing point of the aqueous solution can be lowered reliably. It has little impact on the environment and is effective for economic efficiency in the future. It is easy to handle and can be used for various applications such as road surface antifreezing agents and electrothermal liquids for electric heating systems. Disodium succinate, disodium succinate hexahydrate, and sodium propionate are all solid at room temperature and are water-soluble, so they can be handled, transported, stored, or sprayed in either solid or aqueous solutions. The degree is high.

  When this freezing point depressant is used as a road surface anti-freezing agent, the conventional road surface anti-freezing agent made of chloride alone causes salt damage, but it is effectively mixed with the freezing point depressant to suppress salt damage. It is possible to suppress the occurrence of rust on metal bridges, road signs, passing vehicles, etc., prevent deterioration of concrete tunnels and bridges, and prevent roadside trees from withering. Moreover, it can be mixed with conventional chlorides such as sodium chloride, calcium chloride and magnesium chloride. Disodium succinate, disodium succinate hexahydrate and sodium propionate are Compared with corrosive antifreezing agents (CMA, urea, etc.), it is inexpensive and economical without increasing the price. In addition, there is no odor, and even if sprayed over a wide area, there will be no discomfort to residents and passersby around the road. The road surface freezing agent of this embodiment can be applied in the same manner as a road surface freezing agent made of chloride alone, and can be used immediately. When utilizing the existing spraying system, it is necessary to store the sample outdoors, and highly hygroscopic substances change, such as solidification, but this freezing point depressant has no change and can be stored outdoors. Existing spraying system can be used. Since a volatile organic solvent (VOC), acetate salt, ammonium salt or the like is not required, no bad odor is generated and the influence on the environment and human body is small.

  In addition, it can be produced by fermentation from raw materials such as plants, and since it is a plant-derived component, it is environmentally friendly and promotes the utilization of the bio industry. It is an environmentally friendly anti-freezing agent for road surfaces, and is expected to decrease in price as it spreads in the future, which is advantageous in terms of cost. The fossil fuel that causes carbon dioxide generation is not made from (petroleum, natural gas) based materials, but can be produced from plants that can be regenerated by fermentation, and this also has an impact on the environment. Is small. Fossil fuels are expected to continue to increase in price and are economical in that they do not contain substances made from fossil fuels.

  In addition, according to the freezing point depressant of the present invention, in addition to the above-described components, other components can be blended within a range not departing from the gist of the present invention. In consideration of safety and the environment, each component can be composed only of substances permitted as food additives. The method of using the freezing point depressant can be used for various applications such as a heat medium of an electric heating system in addition to the road surface antifreezing agent.

  About the disodium succinate, the disodium succinate hexahydrate, and the sodium propionate, the freezing point of the mixture with sodium chloride was measured. The measurement method is to make a 10-40% aqueous solution with a sample, put it in a test tube, and put this test tube together with a thermometer in acetone that has been cooled to about 0 ° C. using a cooler in a Dewar bottle. The mixture was cooled with stirring with a stirrer, and the temperature was measured using a thermometer every 30 seconds. The temperature decreased with time, but at a certain time, the temperature increased, and then the temperature decreased again. The temperature that increased and decreased again was measured as the freezing point. The mixing ratio with sodium chloride was measured for 0%, 10%, 20%, 30%, and 40%, each sample was measured twice, and the average value was described. The results are shown in Table 1.

Also, a hygroscopic test was conducted. The hygroscopicity test method is as follows: Disodium succinate, disodium succinate hexahydrate, sodium propionate, put a mixture with sodium chloride into a sample bottle, cover with medicine wrapping paper, and make some holes. Stored for 1 week and observed changes in sample. The results are shown in Table 1.

  Thereby, sodium propionate, disodium succinate, disodium succinate hexahydrate has a low freezing point and is effective as a freezing point depressant. When mixed with sodium chloride, the freezing point dropped more. The mixing ratio is suitably 5 to 20 parts by mass with respect to 100 parts by mass of sodium chloride. Further, in the hygroscopicity test, it was found that there was no change such as solidification in the state after one week, and there was stability.

Next, a metal corrosivity test was performed on sodium propionate and disodium succinate. As a control, the same test was conducted with distilled water, special grade reagent sodium chloride, special grade reagent calcium chloride (anhydrous), and a 2: 8 mixture of disodium succinate and sodium chloride. The test method will be described. Put cathodic iron plate for Hull cell test (67 × 50 × 0.3mm) in 5% sulfuric acid solution for 1-2 minutes, remove galvanization, wash it with water, quickly wash in order of alcohol, acetone, nitrogen gas Were dried by spraying, stored in a desiccator and weighed. A 3 wt% aqueous solution obtained by dissolving the road surface antifreezing agent of the present invention product in water as a test solution was used as a test solution (wet test piece kept at 23 ° C for 24 hours, then removed from the test solution) 24 hours) was repeated over 7 days. The rust generated on the test piece is removed by adding it to a solution of 1% propargyl alcohol with respect to 5% hydrochloric acid for several minutes to 10 minutes. Then, it was washed and dried with alcohol and acetone, and the weight was measured. From the data obtained in this corrosive test, the corrosion reduction rate was calculated as follows.
(Mg / dm ² * day) = (initial weight−post-test weight) × 100 / total sample area × 7
The results are shown in Table 2.

  Accordingly, it was found that the corrosion reduction rates of sodium propionate and disodium succinate were both 0.3 mdd, and the progress of corrosion was smaller than that of distilled water, special grade reagent sodium chloride, and special grade reagent calcium chloride (anhydrous). Furthermore, even in a 2: 8 mixture of disodium succinate and sodium chloride, the corrosion reduction rate is 2.8 mdd, and even if sodium chloride is mixed, the progress of corrosion can be suppressed to a level significantly lower than that of distilled water. It was confirmed that even in the 1: 9 mixture of disodium succinate and sodium chloride, the corrosion reduction rate was 7.3 mdd, which was suppressed to a level lower than that of distilled water. Furthermore, even in a 2: 8 mixture of disodium propionate and sodium chloride, the corrosion reduction rate is 4.4 mdd, and even when sodium chloride is mixed, the progress of corrosion is suppressed to a level significantly lower than that of distilled water. .

  Next, when the freezing point depressant of the present invention was used as a road surface freezing agent, it was verified how the freezing point is changed when glycerin is mixed. The measurement method was as follows. First, an aqueous solution in which the glycerin concentration was changed was prepared, the reagent was dissolved therein to a concentration of 20%, and the freezing point was measured in the same manner as in Table 1. First, the reagent was sodium chloride. The result is shown in FIG.

  When the concentration of glycerin was in the range of 0 to 25%, sodium chloride was dissolved to obtain an aqueous solution. The freezing points at glycerin concentrations of 20% and 25% were −29.5 ° C. and −39.7 ° C., respectively, which were sufficient as antifreeze agents. However, the problem is that it takes too much time to completely dissolve. When the concentration of glycerin was 10%, the freezing point was −25.9 ° C. and the dissolution was smooth. When the concentration of glycerin was 5%, the freezing point was almost the same as that of water alone.

  Next, the change in freezing point was measured when sodium propionate, disodium succinate, and disodium succinate hexahydrate were mixed at a concentration of 20% with a 10% aqueous solution of glycerin. The result is shown in FIG. As a result, it was found that the freezing point was lowered by about 4 to 6 ° C. by mixing glycerin.

  From the results of the above test, it was found that the freezing point depressant of the present invention has a high antifreezing effect, no problem in hygroscopicity, and suppresses metal corrosion. And it turned out that it becomes a road surface anti-freezing agent with a higher effect by mixing with glycerin.

Claims (7)

  A freezing point depressant comprising succinate or propionate.   The freezing point depressant according to claim 1, wherein the succinate is disodium succinate or disodium succinate hexahydrate, and the propionate is sodium propionate.   The freezing point depressant according to claim 1 or 2, comprising the succinate or propionic acid and glycerin.   The freezing point depressant according to claim 3, wherein the glycerin is mixed at a concentration of 5 to 20%.   The at least 1 sort (s) of chloride chosen from sodium chloride, calcium chloride, and magnesium chloride, and the said freezing point depressant are mixed, and it is spread on the road surface of the frozen road of a cold region, and is sprayed. How to use freezing point depressants.   The mixing ratio of the road surface antifreezing agent is 5 to 20 parts by mass of disodium succinate, disodium succinate / hexahydrate or sodium propionate with respect to 100 parts by mass of the chloride. To use freezing point depressants. The method for using a freezing point depressant according to claim 6, wherein glycerin is mixed with the disodium succinate, the disodium succinate hexahydrate, or the sodium propionate.