WO2023145555A1

WO2023145555A1 - Method for producing coolant additive or coolant, and coolant additive

Info

Publication number: WO2023145555A1
Application number: PCT/JP2023/001273
Authority: WO
Inventors: 勇士佐々木
Original assignee: 株式会社Moresco
Priority date: 2022-01-26
Filing date: 2023-01-18
Publication date: 2023-08-03

Abstract

Provided is a coolant additive that can be used in the production of a non-phosphate coolant. This method for producing a coolant additive includes a reaction step for mixing and reacting water, an alcohol, a silicate, and a metal coupling agent.

Description

COOLANT ADDITIVE OR COOLANT PRODUCTION METHOD, AND COOLANT ADDITIVE

The present invention relates to a coolant additive or a coolant manufacturing method, and a coolant additive.

As coolants such as engine coolants, coolants containing phosphoric compounds, which are excellent in rust prevention of iron or aluminum, are often used. On the other hand, when hard water is used as the diluent water for the coolant, phosphoric acid and minerals chemically react to form precipitates, which reduces the rust prevention function of the engine coolant. In addition, there is an increasing trend to reduce the amount of phosphoric acid used, which causes eutrophication, and the development of a non-phosphoric cooling liquid is desired.

For example, Patent Document 1 discloses a coolant composition containing alcohol, silicate and a calcium compound.

Japanese Unexamined Patent Publication JP-A-7-70558

However, when the composition of Patent Document 1 is used as a cooling liquid, the cooling liquid tends to become unstable due to gelation of the cooling liquid because the composition contains silicate. Therefore, the development of a non-phosphoric cooling liquid with suppressed gelation is desired.

Therefore, an object of one aspect of the present invention is to provide a coolant additive that can be used in the production of a non-phosphate coolant.

In order to achieve the above object, the present inventors have made intensive studies and found that gelation is suppressed and stabilized by using a coolant additive produced by mixing and reacting specific components. It was found that a cooling liquid with high performance can be produced. In addition, the inventors have found that the cooling liquid has the same antirust property as that of the phosphoric acid-based cooling liquid, and have completed the present invention.

That is, the present invention consists of the following configurations.
- A method for producing a coolant additive, which comprises a reaction step of mixing and reacting water, an alcohol, a silicate, and a metal coupling agent.
• Additives for coolants, including mixtures of water, alcohols, silicates, metal coupling agents, and partial reactions of these components.

According to one aspect of the present invention, it is possible to provide a coolant additive that can be used in the production of non-phosphate coolants.

4 is a diagram showing the results of a stability test of Evaluation Example 1. FIG. FIG. 10 is a diagram showing the results of an aluminum casting heat transfer surface corrosion test in Evaluation Example 4; FIG. 10 is a diagram showing the results of a metal corrosiveness test in Evaluation Example 4; FIG. 10 is a diagram showing the results of a metal corrosiveness test in Evaluation Example 5; FIG. 10 is a diagram showing the results of a hard water stability test in Evaluation Example 6; FIG. 12 is a diagram showing evaluation results of Evaluation Example 8;

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to this, and various modifications are possible within the scope described, and the present invention also includes embodiments obtained by appropriately combining technical means disclosed in different embodiments. included in the technical scope of Unless otherwise specified in this specification, "A to B" representing a numerical range intends "A or more and B or less".

[1. Manufacturing method of coolant additive]
A method for producing a coolant additive according to an aspect of the present invention includes a reaction step of mixing and reacting water, alcohol, silicate, and a metal coupling agent.

As used herein, the term "metal coupling agent" refers to a compound having two or more different reactive groups (e.g., an epoxy group and an alkoxysilyl group), which serves to bind two or more different substances. It is not limited to things. Moreover, when it has three or more reactive groups, at least any two of them may be different reactive groups.

A coolant additive containing at least water, a silicate, or a reactant in which a metal coupling agent has reacted can be produced by the above-described reaction step. The coolant additive will be described later.

(water)
The water used in the method for producing a coolant additive according to one aspect of the present invention may be ultrapure water, pure water, or purified water such as distilled water.

(alcohol)
The alcohol used in the method for producing a coolant additive according to one aspect of the present invention may be monohydric alcohols or polyhydric alcohols. Additionally, the alcohol may be a primary, secondary or tertiary alcohol. The alcohol is preferably a polyhydric alcohol, more preferably an aliphatic polyhydric alcohol, and even more preferably a primary aliphatic polyhydric alcohol. The alcohol is preferably glycol or glycol ether in terms of suppressing gelation of the cooling liquid and freezing of the cooling liquid. The lower limit of the number of carbon atoms in the alcohol is preferably 2 or more from the viewpoint of suppressing gelation of the cooling liquid. Moreover, the upper limit of the number of carbon atoms in the alcohol is preferably 10 or less, more preferably 5 or less, from the viewpoint of suppressing gelation of the cooling liquid.

Examples of preferred alcohols include ethylene glycol, propylene glycol, diethylene glycol, glycerin, 1,3-propanediol and the like. Among these alcohols, ethylene glycol or propylene glycol is more preferable, and ethylene glycol is even more preferable, from the viewpoint of suppressing gelation of the coolant and suppression of freezing of the coolant. The use of ethylene glycol improves the rust resistance to aluminum.

(silicate)
The silicate used in the method for producing a coolant additive according to one aspect of the present invention is a silicate containing an element of Group 1 or an element of Group 2 of the periodic table in terms of improving rust resistance. Acid salts are preferred.

A material represented by nX ₂ O·mSiO ₂ is an example of a composition formula of a silicate containing an element of Group 1 or Group 2 of the periodic table. Examples of X include alkali metals or alkaline earth metals such as potassium, sodium, lithium, magnesium, and calcium. n and m are preferably 0.1-10. The structure of the silicate may be ortho-, meta-, pyro-, or the like. Among the silicates containing alkali metals or alkaline earth metals, alkali metal silicates are more preferable, and potassium silicate represented by the compound name is even more preferable, from the viewpoint of improving rust resistance.

(metal coupling agent)
The metal coupling agent used in the method for producing a coolant additive according to one aspect of the present invention means a coupling agent containing a metal element such as titanium, zirconium, aluminum or silicon. Among them, a silane coupling agent is preferable from the viewpoint of suppressing the generation of gel in the cooling liquid.

Examples of titanium coupling agents include titanium alkoxides. Examples of zirconium coupling agents include zirconium alkoxide and the like. Aluminum alkoxide etc. are mentioned as an aluminum coupling agent.

Examples of silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyl Diethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3- aminopropyltrimethoxysilane, 3-ureidopropyltrialkoxysilane, 3-isocyanatopropyltriethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropyltrimethoxysilane and the like. Organic functional groups attached to silane coupling agents include vinyl groups, epoxy groups, styryl groups, methacrylic groups, acryl groups, amino groups, ureido groups, isocyanate groups, isocyanurate groups, mercapto groups, methylene groups, and the like. . The number of hydroxyl groups attached to the silanol group is preferably 1 or more and 3 or less. A silane coupling agent having an epoxy group is more preferable in that it suppresses gelling of the cooling liquid and does not have an unpleasant odor, and 3-glycidoxypropyltrimethoxysilane (hereinafter referred to as "3-GPTMS"). ) is more preferable.

(Conditions of the reaction step)
In the reaction step, water, alcohol, silicate, and metal coupling agent are mixed to prepare a mixture.

The lower limit of the amount of the metal coupling agent is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more in 100% by mass of the mixture. The upper limit of the amount of the metal coupling agent is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. When the amount of the metal coupling agent is within the above range, the reaction proceeds efficiently. In addition, even when a coolant is produced by mixing ethylene glycol, water, or the like with a coolant composition, gelation is further suppressed and the coolant is stabilized.

The lower limit of the amount of silicate is preferably 12.5% by mass or more, more preferably 15% by mass or more, and more preferably 17.5% by mass or more in 100% by mass of the mixture. preferable. The upper limit of the amount of silicate is preferably 25% by mass or less, more preferably 22.5% by mass or less, and even more preferably 20% by mass or less. When the amount of silicate is within the above range, the reaction proceeds efficiently, and even when used as a cooling liquid, it exhibits good rust prevention properties.

The lower limit of the amount of alcohol may be 0.1% by mass or more, 1% by mass or more, 2% by mass or more, or 5% by mass or more in 100% by mass of the above mixture. may be Moreover, the upper limit of the amount of alcohol may be 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less. When the amount of alcohol is within the above range, the reaction proceeds efficiently. In addition, by reacting a mixture containing an alcohol within the above range with a silicate and a metal coupling agent, rust prevention against aluminum is improved.

The lower limit of the amount of water is preferably 22.5% by mass or more, more preferably 35% by mass or more, based on 100% by mass of the mixture. Also, the upper limit of the amount of water is preferably 75% by mass or less, more preferably 60% by mass or less. When the amount of water is within the above range, the reaction proceeds efficiently. As one aspect, the blending amount of water is preferably larger than the blending amounts of the metal coupling agent, silicate, and alcohol from the viewpoint of facilitating adjustment of the coolant containing the coolant additive.

When preparing the mixture, the order of mixing is not particularly limited, but from the viewpoint of the stability of the coolant additive, water and silicate may be mixed before the metal coupling agent is mixed. preferable. The mixture may be prepared by a known method such as stirring.

The reaction temperature is usually 20°C to 80°C, preferably 25°C to 60°C, because the evaporation of the components in the reaction process is small and the manufacturing equipment can be simplified. In order to stabilize the quality, the reaction time is usually 3 hours to 100 hours, preferably 5 hours to 80 hours.

After preparing the above mixture, it is preferable to react the above mixture for a period of time that satisfies the following formula (A) or longer in order to promote the synthesis of the compound described below. During the reaction step, the mixture may be allowed to stand still, or may be fluidized by stirring or the like.
y≧7.58x−22.9 (A)
In formula (A),
x=1000/(273.14+T),
y=ln(h) and
T represents a temperature (unit: ° C.) that satisfies 0 ≤ T ≤ 100,
h represents time (unit: hour).

After the mixture is prepared, it is more preferable to leave the mixture at rest or stir for a period of time that satisfies the following formula (B) or longer, in order to promote the synthesis of the compound described below.
y≧7.58x−21.1 (B)
In formula (B),
x=1000/(273.14+T),
y=ln(h) and
T represents a temperature (unit: ° C.) that satisfies 0 ≤ T ≤ 100,
h represents time (unit: hour).

The lower limit of T in formulas (A) and (B) is preferably 0°C or higher, more preferably 10°C or higher, and even more preferably 20°C or higher. The upper limit of T is preferably 100°C or lower, more preferably 85°C or lower, and even more preferably 70°C or lower. When T is within the above range, evaporation of the components is small, so that the production equipment for the coolant additive can be simplified. Further, when T is within the above range, the stability of the coolant additive or the coolant containing the coolant additive is improved.

The lower limit of h in formulas (A) and (B) may be 1 hour or more, 7 hours or more, 14 hours or more, or 24 hours or more, It may be 48 hours or longer, or 72 hours or longer. Also, the upper limit of h may be 1000 hours or less, 360 hours or less, 120 hours or less, or 96 hours or less. When h is within the above range, the stability of the coolant additive or the coolant containing the coolant additive is improved. From the viewpoint of simplification of equipment and stabilization of quality, it is desirable to carry out the reaction at 30 to 40° C. for 70 hours or more.

A coolant additive manufactured by the method for manufacturing a coolant additive according to one aspect of the present invention described above is also included in one aspect of the present invention.

[2. Cooling liquid manufacturing method]
A method for manufacturing a coolant according to one aspect of the present invention may include a step of manufacturing a coolant additive by the method for manufacturing a coolant additive according to one aspect of the present invention.

In the method for producing a coolant according to one aspect of the present invention, the coolant additive produced by the method for producing a coolant additive according to one aspect of the present invention includes water such as ion-exchanged water, ethylene A solvent such as glycol; an organic acid; a neutralizer (pH adjuster); a coloring agent;

The amount of the coolant additive in the coolant according to one aspect of the present invention can be appropriately adjusted according to the application. 05% by mass or more, and more preferably 0.1% by mass or more. Further, the upper limit of the amount of the coolant additive is preferably 3% by mass or less, more preferably 1% by mass or less. When the amount of the coolant additive is within the above range, the rust prevention and stability of the coolant are further improved. Further, when the amount of the additive for coolant is within the above range, the coolant exhibits sufficient anticorrosiveness to metals.

[3. Coolant Additive and Coolant]
A coolant additive according to one aspect of the present invention includes a mixture of water, an alcohol, a silicate, and a metal coupling agent, and a partial reaction product obtained by reacting these components. A "partial reactant" refers to a reactant produced by reacting at least two components contained in a liquid, or a reactant produced by reacting the same components with each other. For example, a reaction product of a metal coupling agent and water, a reaction product of a metal coupling agent and a silicate, a reaction product of a metal coupling agent, a silicate and water, a reaction product of a silicate and a silicate A reactant, or a reactant of water, silicate and/or a metal coupling agent with an alcohol, and the like. Further, one aspect of the present invention also includes a coolant additive manufactured by the method for manufacturing a coolant additive according to one aspect of the present invention.

A coolant according to one aspect of the present invention contains the coolant additive. Further, one aspect of the present invention also includes a coolant manufactured by a method for manufacturing a coolant according to one aspect of the present invention.

The cooling liquid according to one aspect of the present invention has high stability. In addition, although the cooling liquid according to one aspect of the present invention is a non-phosphoric cooling liquid, it has the same anticorrosion properties as the phosphoric acid cooling liquid. In addition, the cooling liquid according to one aspect of the present invention is a non-phosphate cooling liquid and has excellent hard water stability.

Applications of coolants include coolants and antifreeze used in internal combustion engines such as diesel engines and gasoline engines, batteries such as fuel cells and secondary batteries, heat pipes, and motors. Among others, it can be suitably used as a coolant for internal combustion engines.

[4. Coolant additive]
A coolant additive according to an aspect of the present invention includes a compound represented by the following formula (1) as a partial reaction product.

In formula (1),
Each of R ₁ to R ₃ is independently a hydroxyl group, an alkyl group having an ether bond, or an amide group, any two of R ₁ to R ₃ may be bonded to each other, and the bonding group is a ketone may be a base,
R ₄ is an alkyl group having 1 to 10 carbon atoms, -(CH ₂ ) _{Z 1} -CO-NH-(CH ₂ ) _{Z 2} -, or -(CH ₂ ) _{Z 3} -SH ₂ -(CH ₂ ) _{Z 4} - Yes, 1 ≤ Z1 + Z2 ≤ 10, 1 ≤ Z3 + Z4 ≤ 10,
_R5 is an alkyl group having 1 to 10 carbon atoms, isopropyl group, vinyl group, styryl group, acryl group, amino group, carboxyl group, ureido group, mercapto group, isocyanate group, silanol group, hydroxy group, aldehyde group, carbonyl a nitro group, a sulfone group, a phenyl group, a naphthyl group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a triazole group, an epoxy group, a hydrocarbon ring group, or a heterocyclic group;
The compound of formula (1) may form a dimer or multimer with one or more of R ₁ to R ₃ as a linking group, and the linking group has an ether bond.

The coolant additive according to one aspect of the present invention preferably contains any one of the compounds represented by the following formulas (2) to (9) as a partial reaction product, and the following formulas (2) and (3) , (6) or (7), and more preferably a compound represented by the following formula (2) or (6).

As a method for identifying the structure of the compound contained in the coolant additive according to one aspect of the present invention, identification by analysis by mass spectrometry (MS), nuclear magnetic resonance (NMR), or the like can be mentioned.

The coolant according to one aspect of the present invention has an excellent rust-preventing effect on metals even if it does not contain phosphoric acid. By using the cooling liquid according to one aspect of the present invention, it is possible to prevent and reduce water pollution due to eutrophication in lakes, inland seas, etc., and contribute to the achievement of Sustainable Development Goals (SDGs).

〔summary〕
One embodiment of the present invention includes the following configurations.
[1] A method for producing a coolant additive, comprising a reaction step of mixing and reacting water, an alcohol, a silicate, and a metal coupling agent.
[2] The coolant according to [1], wherein the metal coupling agent is at least one coupling agent selected from titanium coupling agents, zirconium coupling agents, aluminum coupling agents and silane coupling agents. manufacturing method of additive for
[3] The method for producing a coolant additive according to [1] or [2], wherein the metal coupling agent is 3-glycidoxypropyltrimethoxysilane.
[4] Production of the coolant additive according to any one of [1] to [3], wherein in the reaction step, the metal coupling agent is added after mixing the water and the silicate. Method.
[5] A method for producing a coolant, comprising a step of producing a coolant additive by the method for producing a coolant additive according to any one of [1] to [4].
[6] A coolant additive comprising a mixture of water, an alcohol, a silicate and a metal coupling agent, and a partial reaction product of these components.
[7] The partial reaction product includes a reaction product of the metal coupling agent and the water, a reaction product of the metal coupling agent and the silicate, and a reaction product of the metal coupling agent, the silicate and the The coolant additive according to [6], which is at least one selected from the group consisting of a reaction product with water.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, % represents % by mass unless otherwise specified. In the preparation examples, addition is performed by dropping, but the addition may not be by dropping. In the preparation examples, the mixture is allowed to stand still in the reaction step, but the mixture may be fluidized continuously or intermittently by stirring or the like.

(Preparation Example 1) Additive for coolant and preparation of coolant In a beaker, 34% ultrapure water and 38% 50% potassium silicate aqueous solution (1K potassium silicate manufactured by Nippon Kagaku Kogyo Co., Ltd.) (that is, silicic acid 19% potassium, 19% water), 22% 3-GPTMS and 6% ethylene glycol (hereinafter sometimes abbreviated as “EG”) were added dropwise with stirring in this order. Then, the mixture obtained by dropping and stirring was allowed to stand in a constant temperature bath at 0° C. or 30° C. under the reaction conditions shown in Table 1 for 1, 2, or 3 days to prepare a coolant additive. The obtained coolant additives 1 to 6 were prepared by mixing with ethylene glycol containing an organic acid and a neutralizer at the coolant formulation ratio shown in Table 1, and evaluated as coolants 1 to 6. . The organic acid and the neutralizing agent are additives generally contained in the cooling liquid, and do not affect the stability of the cooling liquid, and the neutralizing agent does not contribute to the anti-corrosion properties.

(Preparation Example 2) Additives for coolant and preparation of coolant In a beaker, 34% ultrapure water, 38% 50% potassium silicate aqueous solution, 22% 3-GPTMS and 6% EG are added in this order. Stirred dropwise. Additive 7 for cooling liquid was obtained by dropping and stirring without standing and heating. It was prepared by mixing it with ethylene glycol containing an organic acid and a neutralizing agent at the cooling liquid formulation ratio shown in Table 1, and evaluated as cooling liquid 7.

(Evaluation Example 1) Stability Test of Cooling Liquid Cooling liquids 1 to 7 obtained in Preparation Examples 1 and 2 were allowed to stand in a constant temperature bath at 60° C. for 1 hour to evaluate the stability of the cooling liquid. Table 1 shows the evaluation results.

Fig. 1 shows the cooling liquids 3 and 7 after standing for 1 hour in a constant temperature bath at 60°C. In FIG. 1, the cooling liquid (50% diluted liquid) is the cooling liquid obtained by diluting with ultrapure water.

As shown in Table 1, in the cooling liquids 1 to 3 containing the cooling liquid additive obtained by setting the standing temperature to 30 ° C. and standing for one day or more, the cooling liquid is stable and cloudy or precipitated. did not occur, and gelling of the coolant was suppressed. Moreover, as shown in FIG. 1, the cooling liquid 3 was transparent and had good properties. The stability of the cooling liquid was maintained even when the cooling liquid 3 and ultrapure water were mixed to dilute the cooling liquid concentration to 50%. The

cooling liquids

1 and 2 also gave the same results as the cooling liquid 3.

Cooling liquids 4 to 6 containing cooling liquid additives with the stationary temperature set to 0°C became cloudy and the cooling liquid was unstable. On the other hand, although not shown in Table 1, no precipitation or white turbidity occurred in the coolant containing the additive for coolant obtained by standing at 0° C. for 37 days. From these results, in the manufacture of coolant additives, if the standing temperature is low, the gelling of the coolant may be suppressed by extending the standing time, but the stability of the coolant can be ensured. It has been suggested that it is difficult

As shown in Table 1 and Fig. 1, the cooling liquid 7, in which the mixture was not allowed to react in the preparation of the cooling liquid additive, became cloudy and the cooling liquid was unstable. Further, even when the cooling liquid 7 and ultrapure water were mixed to dilute the cooling liquid to a concentration of 50%, the cooling liquid became cloudy and had unstable properties. This is probably because the coolant 7 was prepared by diluting the coolant additive 7 which had a low reaction rate because no reaction time was provided. From this result, it is considered that the coolant is stabilized by chemically reacting the mixture at a constant temperature and time and generating the coolant using the coolant additive in a state of high reaction rate.

(Evaluation Example 2) Examination test of the ratio of each component in the coolant additive Next, without changing the blending ratio of potassium silicate and EG, the blending ratio of 3-GPTMS was changed, and the performance of the coolant was evaluated. was evaluated. Into a beaker, ultrapure water, 38% 50% potassium silicate aqueous solution, 6% EG and 3-GPTMS were dropped and stirred in this order. The percentage of 3-GPTMS was set at 12%, 17%, 22%, 27% and 32% and water was added to make the mixture 100%. The resulting mixture was allowed to stand at 30° C. for 3 days to prepare a coolant additive. 0.4% of the resulting coolant additive and ethylene glycol containing an organic acid and a neutralizing agent were mixed in the same ratio as the coolant formulation shown in Table 1 to prepare a coolant and evaluate it. did

In addition, we evaluated changes in coolant performance by changing the mixing ratio of potassium silicate. Ultrapure water, 50% potassium silicate aqueous solution, 22% 3-GPTMS and 6% EG were added dropwise and stirred in this order into a beaker. The proportions of 50% potassium silicate aqueous solution were set at 28%, 33%, 38%, 43% and 48% and water was added to make the mixture 100%. The resulting mixture was allowed to stand at 30° C. for 3 days to prepare a coolant additive. The obtained additive for coolant and ethylene glycol containing an organic acid and a neutralizing agent were mixed in the same ratio as the coolant formulation shown in Table 1 to prepare a coolant and evaluated.

A metal corrosiveness test was performed on the coolant prepared above. These tests were conducted in accordance with JISK2234:2018 Antifreeze. Evaluation results are shown in Tables 2 and 3.

As shown in Table 2, even when the blending ratio of 3-GPTMS was 12 to 32%, the components contained in the mixture reacted, and the coolant exhibited good rust prevention properties.

As shown in Table 3, even when the mixing ratio of potassium silicate was 14 to 24%, the components contained in the mixture reacted, and the coolant exhibited good rust prevention properties.

(Evaluation Example 3) Examination test of the addition timing of each component of the coolant additive evaluated. Additives 9 to 12 for cooling liquid were prepared by dropping and stirring in a beaker in the order of addition shown in Table 4. The amount of each component charged in preparing the coolant additive was 34% ultrapure water, 38% 50% potassium silicate aqueous solution, 22% 3-GPTMS, and 6% EG.

As shown in Table 4, cloudiness did not occur during the preparation of coolant additives 9 and 11. In the preparation of coolant additive 10, white turbidity (gelation) occurred after addition of the potassium silicate aqueous solution. On the other hand, when all the components were stirred dropwise and allowed to stand in a constant temperature bath at 30°C for several days, the coolant additive became transparent. Coolant Additive 10 could be used, but the preparation of Coolant Additive 10 took longer than the preparation of Coolant Additives 9 and 11 to eliminate cloudiness.

Also, in the preparation of the coolant additive 12, white turbidity occurred after water was added, but the white turbidity disappeared when the potassium silicate aqueous solution was added. The white turbidity disappears after all the components are mixed, so it is acceptable, but for stable preparation, it is desirable that the white turbidity does not occur even during the preparation.

From these results, it was found that it is preferable to add 3-GPTMS after mixing water and an aqueous solution of potassium silicate so that cloudiness does not occur during preparation of the coolant additive.

(Evaluation Example 4) Evaluation Test of Engine Coolant The coolant additive 3 prepared in Preparation Example 1 was mixed with ethylene glycol containing an organic acid and a neutralizer to obtain an engine coolant (0.00% additive for coolant). 2 to 10%) was prepared. The prepared engine coolant was subjected to an aluminum casting heat transfer surface corrosion test and a metal corrosion test. These tests were conducted according to JISK2234:2018 antifreeze solution. An aqueous solution with a volume fraction of 30% was prepared from the engine coolant, and the results of the aluminum casting heat transfer surface corrosion test are shown in FIG. 2, and the results of the metal corrosion test are shown in FIG.

　From Figures 2 and 3, it was confirmed that the engine coolant containing 0.3 to 4% of additive 3 for coolant has anti-corrosion properties. In Evaluation Example 4, it was found from the results of the JIS test that the optimum content of the coolant additive prepared in Preparation Example 1 in the coolant was 0.4%. The optimum content of the coolant additive in the coolant varies depending on the blending amount of each component of the coolant additive.

(Evaluation Example 5) Evaluation Test of Anticorrosiveness of Coolant A metal corrosiveness test (according to JISK2234:2018 antifreeze liquid) was performed on samples a to d shown below to evaluate the anticorrosive effect. The coolant was diluted with water, and the metal corrosion test was performed using a 30% aqueous solution, and the aluminum heat transfer surface test was performed using a 25% aqueous solution. FIG. 4 shows the evaluation results of the rust prevention properties of each cooling liquid.
Sample a... Coolant 3 prepared in Preparation Example 1
Sample b: commercially available phosphoric acid-based cooling liquid Sample c: commercially available silicic acid-based cooling liquid Sample d: commercially available organic acid-based cooling liquid

As shown in Fig. 4, it was confirmed that sample a had the same anticorrosive properties as samples b to d of commercial cooling liquids.

(Evaluation Example 6) Hard Water Stability Test of Cooling Liquid Samples a and b of Evaluation Example 5 were evaluated for the presence or absence of precipitation when diluted with hard water. Specifically, the samples a and b were evaluated under the following conditions 1 to 4. Evaluation results are shown in FIG.
<Condition 1>
After stirring 100 mL of the sample and 100 mL of hard water (containing 10 ppm of Ca), the mixture was allowed to stand in a dark place for 24 hours.
<Condition 2>
After stirring 100 mL of the sample and 100 mL of hard water (containing 100 ppm of Ca), the mixture was allowed to stand in a dark place for 24 hours.
<Condition 3>
After stirring 100 mL of the sample and 100 mL of hard water (containing 10 ppm of Ca), the mixture was heated to 80° C. and allowed to stand in the dark for 24 hours.
<Condition 4>
After stirring 100 mL of the sample and 100 mL of hard water (containing 100 ppm of Ca), the mixture was heated to 80° C. and allowed to stand in the dark for 24 hours.

As shown in Fig. 5, precipitation occurred in sample b under any of conditions 1 to 4, but no precipitation was observed in sample a. Phosphoric acid-based coolants tend to react with mineral components and precipitate, but sample a did not precipitate and was found to be excellent in hard water stability.

(Evaluation Example 7) Analytical Test of Coolant Additive In the coolant additive prepared in the above evaluation example, the chemical reaction is accelerated by allowing the components to stand at a constant temperature after mixing, and the coolant is stable. It is presumed that it imparts toughness and rust resistance. It is also presumed that reactants produced by the chemical reaction contribute to the stability and rust prevention of the coolant. Therefore, an analytical test was conducted on the components contained in the coolant additive.

The coolant additive 3 prepared in Preparation Example 1 was analyzed by LC-MS. Samples subjected to LC-MS were prepared by dissolving coolant additives in a mixed solution of 10 mM aqueous ammonium bicarbonate and acetonitrile (mixing ratio=1:1). Samples subjected to LC-MS were not concentrated under reduced pressure or heated.

Analysis conditions by LC-MS are shown below.
Apparatus (LC): Agilent 1100 Series manufactured by Agilent Technologies
Apparatus (MS): Bruker Daltonics microTOF focus type Column: Unison UK-C8 (3 μm, 4.6 × 150 mm)
Mobile phase: 10 mM ammonium bicarbonate aqueous solution/acetonitrile = 1/5
Flow rate: 1 mL/min Column temperature (LC part): 40°C
Mass spectrometry temperature (MS section): 190°C
Detection method: ESI (negative mode)
Injection volume: 10 μL

As a result of the analysis, it was speculated that the coolant additive contained the following two compounds. These compounds are believed to have been produced during the reaction process during the preparation of the coolant additive.

Based on the analysis results (molecular weight) by LC-MS, it was suggested that the following two compounds are also included in the coolant additive.

In addition to LC-MS, analysis of coolant additives was also performed by ¹ H-NMR. The NMR analysis results suggested that the following four compounds were also included in the coolant additive.

The compounds of formulas (2) to (9) above are presumed to correspond to reactants of the metal coupling agent and water. The above analysis results were obtained using a silane coupling agent as the metal coupling agent.

Although not confirmed by LC-MS and NMR analysis, the structures of the components (water, 3-GPTMS, EG and potassium silicate) used to prepare the coolant additive produced the compounds shown below. It is possible that

The above four compounds are presumed to correspond to reactants of a metal coupling agent, water, silicate and alcohol, or reactants of a metal coupling agent, water and alcohol. The above compound uses a silane coupling agent as a metal coupling agent.

(Evaluation Example 8) Examination of reaction temperature and reaction time Into a beaker, 34% ultrapure water, 38% 50% potassium silicate aqueous solution, 22% 3-GPTMS and 6% EG were dropped and stirred in this order. . Table 5 shows the reaction time at which the reaction of the metal coupling agent was confirmed when the reaction temperature of the mixture obtained by dropping and stirring was 10 ° C., 20 ° C., 30 ° C., 60 ° C. and 70 ° C. . Further, in Table 6, suppression of gelation in the mixture was confirmed when the reaction temperature of the mixture obtained by dropping and stirring was 10°C, 20°C, 30°C, 60°C, and 70°C. Indicates reaction time.

As shown in Table 5, it was found that when the reaction temperature is low, the metal coupling agent reacts if the reaction time is lengthened. From the results of Evaluation Examples 1 to 7, it is presumed that the reaction product functions as an additive for coolants at any reaction temperature studied in Evaluation Example 8, but if the reaction temperature is low, the production efficiency is poor.

Also, based on the results in Tables 5 and 6, an equation showing the correlation between reaction temperature and reaction time was derived. FIG. 6 shows a graph created for deriving the formula. The circled plots in FIG. 6 are plots obtained by reflecting the data in Table 6, and the following formula (A1) was derived.
y≧7.58x−22.889 (A1)
In formula (A1),
x=1000/(273.14+T),
y=ln(h) and
T represents a temperature (unit: ° C.) that satisfies 0 ≤ T ≤ 100,
h represents time (unit: hour).

The triangle mark plot in FIG. 6 is a plot obtained by reflecting the data in Table 5, and the following formula (B1) was derived.
y≧7.58x−21.089 (B1)
In formula (B1),
x=1000/(273.14+T),
y=ln(h) and
T represents a temperature (unit: ° C.) that satisfies 0 ≤ T ≤ 100,
h represents time (unit: hour).

The reaction temperatures and reaction times in Table 5 satisfy the above formulas (A1) and (B1).
When the reaction was carried out for a time longer than the time satisfying formula (B1), almost no unreacted metal coupling agent was detected, and the reactant was produced without waste. The reaction temperature and reaction time may be appropriately determined, but if the reaction rate is low, the stability of the coolant additive and the coolant will be insufficient.

(Evaluation Example 9) Examination of alcohol addition timing In a beaker, add ultrapure water, 50% potassium silicate aqueous solution, 3-GPTMS and EG in the amounts and procedures shown in Table 7, and add for cooling liquid. formulations were prepared. Table 7 shows the results of various tests conducted using the prepared cooling additive. The stability test was conducted under the same test conditions and compounding conditions as Evaluation Example 1, the metal corrosion test under Evaluation Example 2, and the hard water stability test under Evaluation Example 6.

As shown in Table 7, coolant additive 13 does not have antifreeze properties because EG is not added. Coolant Additives 3, 13 and 14 all showed good results in the stability test, metal corrosion test and hard water stability test. Thereby, by mixing and reacting water, silicate and metal coupling agent, a partial reaction product of these components is generated. It has been found that the inclusion of the partial product provides a coolant additive exhibiting good stability and antirust properties.

In the aluminum rust prevention test, the entire aluminum test piece (AC2A) was immersed in a solution containing 1% of each cooling additive, 1% of sodium hypochlorite, and 98% of water, and was kept at a constant temperature of 60 ° C. The change in weight of the aluminum test piece after standing in the tank for 96 hours was evaluated.

Cooling liquid additive 3, which was produced by mixing alcohol, silicate, water, and a metal coupling agent and leaving the mixture at 30°C for 3 days, had high rust resistance. However, the coolant additive 13 that does not contain alcohol and the coolant additive 14 that is mixed with silicate, water and a metal coupling agent and allowed to stand at 30 ° C. for 3 days and then added with alcohol is not suitable for cooling. The antirust property was inferior to that of Additive 3. From these results, it was found that a coolant additive having an excellent antirust effect can be obtained by mixing and reacting alcohol, water, silicate and a metal coupling agent with the coolant additive. In the coolant additive 3, it is presumed that water, silicate and/or a metal coupling agent react with alcohol to produce a reaction product.

From the above results, as one aspect of the reaction process of the present invention, water, a silicate, and a metal coupling agent are mixed for a predetermined time (for example, several hours to several days), and then alcohol is added. good too.

The present invention can be used as additives for coolants, coolants for engine or battery cooling, rust inhibitor compositions for rust prevention, metalworking compositions for metalworking, and the like.

Claims

A method for manufacturing a coolant additive, which includes a reaction step of mixing and reacting water, alcohol, silicate, and a metal coupling agent.
The coolant additive according to claim 1, wherein the metal coupling agent is at least one coupling agent selected from a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent and a silane coupling agent. manufacturing method.
The method for producing a coolant additive according to claim 1 or 2, wherein the metal coupling agent is 3-glycidoxypropyltrimethoxysilane.
The method for producing a coolant additive according to claim 1 or 2, wherein in the reaction step, the metal coupling agent is added after mixing the water and the silicate.
A method for manufacturing a coolant, comprising a step of manufacturing a coolant additive by the method for manufacturing a coolant additive according to claim 1 or 2.
A coolant additive containing a mixture of water, alcohol, silicate, and a metal coupling agent, and a partial reaction product of these components.
The partial reaction products include a reaction product of the metal coupling agent and the water, a reaction product of the metal coupling agent and the silicate, and a reaction product of the metal coupling agent, the silicate, and the water. 7. The coolant additive according to claim 6, which is at least one selected from the group consisting of a reactant.