JPH01259083A - Antifreezing fluid - Google Patents

Abstract

PURPOSE:To provide an antifreezing liquid for coolant of automobile engine, etc., containing a polyalkylene glycol monoallyl ether and a maleic acid-type monomer, exhibiting improved effect to prevent the corrosion of aluminum and having antifreezing effect as well as corrosion protection effect. CONSTITUTION:The objective antifreezing fluid having a pH of 6.5-9.0 is produced by compounding (A) an antifreezing fluid composed of glycols and water with (B) 24-75mol% of phosphoric acids, dicarboxylic acids, manganese compounds, sodium mercaptobenzothiazole, nitrates, benzoates and a polyalkylene glycol monoallyl ether of formula I (m and n are 0 or integer; m+n=1-100) and (C) 24-75mol% of a maleic acid-type monomer of formula II [R1 and R2 are H or methyl; X and Y are (C2H4O)p(C3H6O)qR3 (R3 is H or 1-20C alkyl; p and q are 0 or integer; p+q=1-100), univalent metal, bivalent metal, ammonium or organic amine] and/or 0-50mol% of a copolymerizable monomer. The sum of the components B and C is 100mol%.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an antifreeze solution comprising glycols, water, and a corrosion inhibitor used to prevent freezing of cooling water of a liquid-cooled internal combustion engine. More specifically, the present invention relates to an antifreeze liquid that is used as a coolant for an automobile engine and is effective in maintaining the functions of the cooling system of an automobile engine, in addition to preventing freezing and preventing rust and corrosion. (Prior Art) Conventionally, the coolant for liquid-cooled internal combustion engines, such as automobile engines, has been made mainly of alcohols or glycols to prevent freezing during cold seasons, and various corrosion inhibitors have been added to this to prevent freezing. Antifreeze is used because it has both corrosion and anti-corrosion properties. (Problems to be solved by the invention) - Methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. are used as alcohols, and ethylene glycol, propylene glycol, hexylene glycol, glycerin, etc. are used alone as glycols. Or they are used in combination. Among these, antifreeze containing monoethylene glycol as a main ingredient is particularly used as a coolant in the cooling system of an automobile engine. In the case of monoethylene glycol aqueous solution, -
At 15.5℃ and 50% by volume, anti-freezing effect up to -37.0"C can be obtained. Alcohols or glycols are oxidized by contact with air, and acidic alcohol or glycol oxides are Under high temperature conditions of 50 to 100°C, the formation of oxides of alcohols or glycols is further promoted.These acidic alcohols or glycols are used in internal combustion engine cooling systems, especially automobile engines. Corrosion of the various metals that make up the cooling system of an internal combustion engine significantly accelerates the corrosion of the various metals that make up the cooling system of an internal combustion engine, resulting in a decrease in thermal conductivity due to deposition of corrosion products or blockage of the radiator pipe, which can cause the engine to overrun. Antifreeze containing alcohols or glycols as a main component has no corrosion-preventing effect on itself, so corrosion inhibitors are added. As anti-corrosion agents, borax and sodium nitrite are added. , phosphoric acid, silicates, sodium benzoate, sodium salt of mercaptobenzothiazole, benzotriazole, methylbenzotriazole, triethanolamine, jetanolamine, monoethanolamine, triisopropanolamine, diisopropanolamine, At least one selected from monoisopropanolamine, cyclohexylamine, ethylenediamine, hydrazine, pyridine, morpoline, etc. is added. Representative among these are borax and phosphate of triethanolamine. , sodium benzoate, sodium nitrite, and sodium gaic acid.Borax has been widely used as an effective anticorrosive agent for cast iron engines, but in recent years it has been used to reduce the weight of automobile parts in order to conserve resources and energy. With the adoption of aluminum parts, it has become a problem that aluminum parts have shortcomings in corrosion resistance. When ethylene glycol water thawed with borax is used in the cooling system of an automobile engine, It is known that the aluminum alloy that is the material of engine cylinder heads and cylinder blocks corrodes, and the corrosion products clog the radiator.On the other hand, triethanolamine phosphate is known to corrode the aluminum alloy that is the material of engine cylinder heads and cylinder blocks. It has excellent anti-corrosion properties and has been used as an anti-corrosive agent in place of borax, but it has since been reported that nitrone amines are produced by the coexistence of triethanolamine and nitrites, so avoid the coexistence of amines and nitrites. However, sodium benzoate alone cannot be expected to be effective enough to replace these anticorrosive agents. On the other hand, silicate sorter is also effective as a corrosion inhibitor, but there is a problem in that sodium silicate tends to gel and separate during long-term storage. That is, an object of the present invention is to provide an antifreeze solution that is a composition that does not contain amines and has particularly excellent aluminum corrosion resistance. As a result of extensive research, the present inventors found that in an antifreeze solution consisting of glycols and water, (A) phosphoric acids, (B) dicarboxylic acids, (C) manganese compounds, (D) mercaptobenzothiazole soda, (E)
Nitrate, (Fbenzoate and (G) General formula (1) % formula %)] (However, in the formula, m and n are 0 or a positive integer, m and n
= 1 to 100, (02H40) unit and fc3H6
0) Units may be combined in any order. ) Polyalkylene glycol monoallyl ether (I) represented by the general formula (2) % formula % [wherein R and R2 each represent hydrogen or a methyl group, and X and Y each represent (C2H
40) p(C3H60), R3 (wherein R3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, and p and q
is 0 or a positive integer, p+q=o~100, and (
02H40) units and (C31160) units may be bonded in any order. ), a maleic acid monomer represented by co representing a monovalent metal, a divalent metal, an ammonium group or an organic amine group (n) and/or a monomer copolymerizable with these (a copolymer derived from I [ was able to achieve the objective. (Means for Solving the Problems) The present invention provides an antifreeze solution comprising glycols and water, (A) phosphoric acids, (B) dicarboxylic acids, (C) a manganese compound, (D) mercaptobenzothiazole soda, ( E)
Nitrate, (F) Benzoate and (G) General formula <1) C112= CH 1...(1) CIl 29 (C2H40), (C3)160
) n H (where m and n in the formula are 0 or positive integers and m+n = 1 to 100, and the (02H40) unit and (C3■60) unit may be combined in any order, ) Polyalkylene glycol monoallyl ether (I) represented by the general formula (2), R1R2 0=C...(2) C02X C02Y [wherein R and R2 each represent a hydrogen methyl group, X and Y are each (C2H
40), (C3H60), R3 (wherein R3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, P and q are 0 or a positive integer, p + q = 0 to 100, (CHO) unit and (C3■60) unit may be bonded in any order), a maleic acid monomer (n ) and/mana is a copolymer derived from a monomer (I [I) copolymerizable with these, and has a pH in the range of 6.5 to 9.0. It is something that takes place in between. Examples of the phosphoric acids of the present invention include phosphoric acids and salts thereof. In addition to orthophosphoric acid, first to tertiary salts of alkali metals such as lithium, sodium, and potassium can be used. The amount added is 0.1 to 5.0 to the undiluted antifreeze solution.
% by weight, preferably 0.5-3. Off amount %. The dicarboxylic acids of the present invention include oxalic acid, malonic acid,
Succinic acid, glutaric acid, adipic acid, piperic acid, speric acid, azelaic acid, cepatic acid, brassylic acid, tabucic acid can be used. Moreover, salts of these dicarboxylic acids can also be used. The amount of dicarboxylic acids added is 0.05 to 1.0%, preferably 0.1 to 0.0%.
It is in the range of 7% by weight. Manganese compounds of the present invention include manganese oxide, manganese hydroxide, manganic acid, potassium permanganate, sodium permanganate, lithium permanganate, magnesium permanganate, manganese chromate, manganese borate, manganese fluoride, and manganese chloride. , manganese bromide, manganese iodide, manganese carbonate, manganese nitrate, manganese sulfite, manganese sulfate, manganese ammonium sulfate, manganese phosphate, manganese hydrogen phosphate, manganese dihydrogen phosphate, manganese ammonium phosphate, manganese formate, manganese acid, oxalic acid Manganese, manganese butyrate, manganese lactate, manganese malonate, manganese tartrate, manganese abutate, manganese glycerate, manganese valerate, manganese maleate, manganese oleate, citric acid, manganese iron citrate, manganese benzoate, manganese salicylate , manganese glutamate, etc. can be used. The amount of the manganese compound of the present invention added is 0.0001 to 0.050% by weight, preferably 0.00% by weight, based on the stock solution of antifreeze.
It ranges from 5 to 0.020% by weight. The amount of sodium mercaptobenzothiazole of the present invention added is in the range of 0.05 to 0.70% by weight, preferably 0.1 to 0.50% by weight, based on the stock solution of antifreeze. As the nitrate of the present invention, alkali metal salts such as sodium salts and potassium salts are used. The amount of nitrate added is 0.05 to 0.70% by weight, preferably 0.05 to 0.70% by weight based on the stock solution of antifreeze.
．． It ranges from 1 to 0.50% by weight. As the benzoate of the present invention, alkali metal salts such as sodium salts and potassium salts are used. The amount of benzoate added is in the range of 1.0 to 7.0% by weight, preferably 2.0 to 7.0% by weight, based on the stock solution of antifreeze. The copolymer of the present invention is a copolymer derived from polyalkylene glycol monoallyl ether (K), a maleic acid monomer (n), and a monomer (I) copolymerizable with these. It can be used, preferably, the general formula (1), CH2=CH1...(1) CH20(C2+140)I(C3H60). H (in the formula, m and n are positive integers less than 0, m + n = 1
~100, (02H40) unit and (C3■60)
The units may be bonded in any order.) Polyalkylene glycol monoallyl ether (I) represented by the general formula (2), R1R2 C=C...(2) C02X Co2Y [However, In the formula, R and R2 each represent hydrogen or a methyl group, and X and Y each represent (C2H
40) rJ (031160) qR3 (wherein R3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, p and q are 0 or a positive integer, P+ (1=O to 100), (02H40) unit and (C3■60) units may be bonded in any order), represents a -valent metal, divalent metal, ammonium group or organic amine group] Maleic acid monomer ( n) and/or a copolymer derived from a monomer (I [I) copolymerizable with these. Polyalkylene glycol monoallyl ether is KOH
It can be synthesized by a known method of directly adding ethylene oxide and/or propylene oxide to allyl alcohol using an alkali such as or NaOH as a catalyst. As long as it is represented by the above general formula, it can be used either as a single structure or as a mixture. The maleic acid monomer (I) is represented by the above general formula, and specifically includes maleic acid, phthalic acid, citraconic acid, mesaconic acid, and monovalent metal salts and divalent metal salts of these acids. Salts, ammonium salts, organic amine salts, and these acids and HO (C2H40), (C3H60), R3 (wherein R3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, and p and q are 0 or a positive integer) So, p+q=o~
100, and (C3H6Q) units and (C2H40) units may be bonded in any order), such as secondary alcohol ethoxylate monomerate. can be suitably used. Moreover, one or more of these can be used. Monomers ([) that can be copolymerized with these include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, and Examples include esters obtained from these acids and alcohols, (meth)acrylamide, vinyl acetate, propenyl acetate, aromatic vinyl compounds such as styrene and p-methylstyrene, vinyl chloride, etc. One or two of these More than one species can be used. The copolymer contains 2 polyalkylene glycol monoallyl ether (■), a maleic acid monomer (II), and/or a half-mer copolymerizable with these (If).
4 to 75 mol%, 24 to 75 mol%, and 0 to 50 mol%, provided that the total of components (I), (II), and (DI) is 100 mol%. ) was derived using the ratio of To produce a copolymer, the monomer components may be copolymerized using a polymerization initiator. Copolymerization can be carried out by polymerization in a solvent, bulk polymerization, or the like. Polymerization in a solvent can be carried out either batchwise or continuously, and the solvents used include water; lower alcohols such as methyl alcohol, ethyl alcohol, and ingropyl alcohol; benzene, toluene, xylene, cyclohexane, Examples include aromatic or aliphatic hydrocarbons such as n-hexane; ethyl acetate; and getone compounds such as acetone and methyl alcohol. From the viewpoint of the raw material monomer Jl#%, the solubility of the resulting copolymer, and the convenience of using the copolymer, at least one selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms should be used. Among the lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, and isopropyl alcohol are particularly effective. When polymerization is carried out in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator. At this time, an accelerator such as sodium hydrogen sulfite can also be used in combination. In addition, for polymerization using lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, ethyl acetate, or ketone compounds as solvents, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; Aliphatic azo compounds such as bisisobutyronitrile are used as polymerization initiators. At this time, a promoter such as an amine compound can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from among the various polymerization initiators or combinations of polymerization initiators and accelerators mentioned above. The polymerization temperature is adjusted appropriately depending on the solvent and polymerization initiator used, but it is usually carried out within the range of 0 to 120°C. In bulk polymerization, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumenepytropaloxide; and aliphatic azo compounds such as azobisisobutyronitrile are used as polymerization initiators.
It is carried out within a temperature range of 50-150°C. The copolymer thus obtained may be used after being further neutralized with an alkaline substance if necessary. Such alkaline substances include hydroxides of -valent metals and divalent metals. , chlorides and carbonates: ammonia; organic amines and the like are preferred. Moreover, the molecular weight of the copolymer can be used in a wide range, but it is preferably in the range of 500 to 50,000. Polyalkylene glycol monoallyl ether (1) contained in the antifreeze of the present invention, maleic acid monomer (I[>
A copolymer derived from the monomer (III) copolymerizable with these has a corrosion inhibiting effect on iron-based materials and a corrosion-inhibiting effect on aluminum-based materials. Thus, the antifreeze of the present invention overcomes the problems associated with automotive antifreeze containing phosphates. The amount of the copolymer derived from the polyalkylene glycol monoallyl ether (1) of the present invention, the maleic acid monomer (II), and the monomer copolymerizable with these (I [ It is 0.01% by weight or more based on the stock solution. In addition, methylbenzotriazole, benzotriazole, etc. can be used. For adjusting the pH of the antifreeze solution, ordinary basic substances can be used, but hydroxides of alkali metals such as lithium, sodium, and potassium are preferably used. Acidic substances such as phosphoric acid can also be used if necessary. The pH adjustment range is 6.5 to 9.0, preferably 7.
．． It is 0 to 8.0. If the pH is higher than this range, the corrosion resistance against aluminum will be poor, and if it is lower, corrosion of iron will occur, so it should be adjusted within the above range. The antifreeze of the present invention includes silicone oil, mineral oil, alcohol,
Antifoaming agents such as higher fatty acid esters can be added. (Function) As is clear from the results of Examples and Comparative Examples described below, the antifreeze solution of the present invention has a significantly improved corrosion prevention effect on aluminum. (Example) Next, the antifreeze solution of the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. [A] Metal corrosion test method [JIS-2234 (antifreeze)] Using metal test pieces of core aluminum casting, cast iron, steel, brass, solder, and copper, mixed water (sodium sulfate 148 mg,
165 mg of sodium chloride and 13 mg of sodium bicarbonate
8mg in 1f of distilled water! (dissolved in) 30% by volume
Soak in antifreeze diluted with 100±10m1 of dry air.
While feeding at a flow rate of /nin, increase the antifreeze temperature to 88±
It was held at 2°C for 672 hours. The mass of each metal piece before and after the test was measured to determine the change in mass. The change in mass of each metal was determined from the following equation. C= (m2-m1)/Swhere, C: Change in mass (m g/C18)m
1: Quality of test piece before testing! L (mg) m2
: Quality of test piece after test 41 (mg) S : Total surface area of test piece before test (cd)

[B] Heat transfer surface corrosion test method (1) Apparatus The top surface of a disk-shaped test piece is in contact with the antifreeze solution, and the bottom surface is heated by a heater, so that heat is transferred to the antifreeze solution through the test piece. The experiment was carried out using a device designed as follows. (2) Test method ■ The test piece is polished with #320 water-resistant abrasive paper so that it becomes flat. ■ Prepare the test solution to 25% by volume with distilled water or pure water. Sodium chloride is added to this solution to give a concentration of 1100 pp as chlorine ions. ■ After injecting the sample into the device, 0.5Kg/aa with air
Apply pressure to G. ■ After the test, remove any deposits from the test piece, dry it, and weigh it accurately. (3) Test conditions Test piece: Aluminum casting (AC2A) Test piece temperature: 135 parts 1°C Antifreeze concentration: 25% by volume aqueous solution Antifreeze liquid volume
: 500 [DI test time: 16
8 hours (continuous) (4) Test item ■ Appearance of test piece ■ Change in mass of test piece The change in mass was determined from the following equation. C= (m2-m1)/Swhere, C: Change in mass (m g/Cl1l
) m 1: Mass of test piece before test (mg) m 2
: Mass of test piece after test (mg) S : Total surface area of test piece before test (Al reference example 1 [Copolymer (
1) Preparation] Polyethylene glycol monoallyl ether (average
334 parts of ethylene oxide units) and 100 parts of water were charged, the inside of the reaction vessel was replaced with nitrogen while stirring, and heated to 95°C in a nitrogen atmosphere, and then 139.3 parts of maleic acid and 14 parts of ammonium persulfate were charged. An aqueous solution of .2 parts dissolved in 225 parts of water was added over 120 minutes. After the addition was completed, 14.2 parts of a 20% aqueous ammonium persulfate solution was further added over 20 minutes. After completion of addition, 95°C for 100 minutes
The temperature in the reaction vessel was maintained to complete the polymerization reaction, and a copolymer water solution was obtained.Next, a 40% aqueous solution of caustic soda was added to neutralize the sodium salt of copolymer (1).
Hereinafter, it will be abbreviated as copolymer (1) Najp. ) An aqueous solution was obtained. The sodium salt aqueous solution of this copolymer (1) has a pH of 9.
5. The viscosity was 203 centiboise. Reference Example 2 [Preparation of copolymer (2)] Polyethylene glycol monoallyl ether (5 ethylene oxide molecules per molecule on average) was placed in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a gas introduction tube, and a reflux condenser. (including units) and 88.5 parts of water,
The inside of the reaction vessel was replaced with nitrogen while stirring, and the temperature was increased to 95% in a nitrogen atmosphere.
heated to ℃. Thereafter, an aqueous solution of 139.3 parts of maleic acid and 11 parts of ammonium persulfate dissolved in 209 parts of water and 2 parts of styrene were added in parallel over 120 minutes. After the addition was complete, 27.8 parts of a 20% aqueous ammonium persulfate solution was added to the fire over 60 minutes. 95 for 90 minutes after completion of addition
The temperature inside the reaction vessel was maintained at ℃ to complete the polymerization reaction and obtain copolymer (2). Then, a 40% by weight aqueous solution of caustic soda was added to neutralize the mixture to obtain an aqueous solution of copolymer (2). This copolymer (2
) had a pH of 9.5 and a viscosity of 198 centiboise. Reference Example 3 [Preparation of copolymer (3)] Polyalkylene glycol monoallyl ether (10 molecules per molecule on average) Containing an ethylene oxide unit and two propylene oxide units) 3
6 parts of 99.degree. Then 75.4 parts of maleic acid and persulfuric acid? An aqueous solution in which 17.1 parts of Nmoni Uno was dissolved in 113.2 parts of water was added over 120 minutes. After the addition is complete, add 1 part of 20% ammonium persulfate aqueous solution to the fire over 20 minutes.
After the addition was completed, the temperature inside the reaction vessel was maintained at 95°C for 100 minutes to complete the polymerization reaction, and a copolymerization solution was obtained.Next, a 40% aqueous solution of caustic soda was added to neutralize the copolymer ( An aqueous solution of copolymer (3) was obtained.This aqueous solution of copolymer (3) had a pf (-') of 5 and a viscosity of 135 cmVoice. parts or monoethylene glycol at the compounding ratio shown in Table 1, and the two solutions were mixed. The following tests and measurements were performed on each sample: rA] Metal corrosion test [B] Heat transfer surface corrosion The test results were as shown in Table 1. Comparative Examples 1 to 7 Samples prepared at the blending ratios in Table 1 were tested in the same manner as Examples 1 to 7. The results were as shown in Table 1. (Effects of the Invention) In the antifreeze solution comprising a glycol compound and water of the present invention, (A> phosphoric acids, (B) dicarboxylic acids, (C) manganese compound, (D) mercaptobenzothiazole soda, (E)
Nitrate, (F) Benzoate and (G) General formula (1) % formula % (However, in the formula, m and n are 0 or a positive integer, and m +
n = 1 to 100, (C21t40) units and (03H60) units may be bonded in any order) Polyalkylene glycol monoallyl ether (I) represented by general formula (2), R1R2 C=C...(2) Co2X C02Y [However, in the formula, R1 and R2 each represent hydrogen or a methyl group, and X and Y each represent (C2H40)
, (C3H60), R3 (R3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, p and q are 0 or a positive integer, p+q=o to 100, (02H40
) units and (C3H60) units may be bonded in any order, ) represents a monovalent metal, a divalent metal, an ammonium group, or an organic amine group. n) and/or a copolymer which is not derived from a monomer (It) copolymerizable with these, and has a pH in the range of 6.5 to 9.0, thereby preventing corrosion against aluminum. The prevention effect is significantly improved. Patent applicant Nippon Shokubai Chemical Co., Ltd. Procedural amendment (
Spontaneous> July 22, 1986

Claims (1)

[Claims] (1) In an antifreeze solution consisting of glycols and water, (A) phosphoric acids, (B) dicarboxylic acids, (C) manganese compounds, (D) mercaptobenzothiazole soda, (E) nitrates, (F) benzoates and (G) General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (However, in the formula, m and n are 0 or positive integers, and m+n
= 1 to 100, and (C_2H_4O) units and (C_3H_6O) units may be combined in any order. ) Polyalkylene glycol monoallyl ether (I), general formula (2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(2) [However, in the formula, R_1 and R_2 each represent hydrogen or a methyl group. and X and Y are each (C_2H
_4O)_p(C_3H_6O)_qR_3(R_3 represents hydrogen or an alkyl group having 1 to 20 carbon atoms, p and q are 0 or a positive integer, p+q=0 to 100, and (C_2H_4O) unit and (C_3H_O) Units may be bonded in any order), monovalent metals, divalent metals, ammonium groups, or organic amine groups. ] A copolymer derived from the maleic acid monomer (II) and/or the monomer (III) copolymerizable with these, and has a pH of 6.5 to 9.0. Antifreeze characterized by a range.