JPH0299599A - Cleaning agent for aluminum heat-exchanger for air-conditioning - Google Patents

Abstract

PURPOSE:To provide the subject cleaning agent containing a polyvalent metal ion sequestering agent, a surfactant and an alkali builder and effective in recovering the lowered hydrophilicity of especially a hydrophilicized surface of an Al fin. CONSTITUTION:The objective cleaning agent contains (A) a polyvalent metal ion sequestering agent consisting of an alkali metal salt of an amino(poly) carboxylic acid, polyphosphoric acid, aluminosilicate carboxylic acid and carboxylic acid, a polyamine compound, an amine compound, etc., (B) preferably an anionic and/or nonionic surfactant and (C) an alkali builder consisting of a carbonate, phosphate, silicate, borate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning agent for aluminum heat exchangers for air conditioning.

[Prior Art] In recent years, heat exchangers for air conditioning have been required to be made more compact, and as a result, it has become necessary to narrow the spacing between fins as much as possible.

By the way, during cooling operation of an air conditioner, moisture in the air adheres to the surface of the aluminum fins of the heat exchanger as condensed water, but this adhered water forms a semicircle or bridge shape on the fin surface to facilitate the smooth flow of air. This increases ventilation resistance and reduces the heat exchange efficiency of air conditioners. As a result of the above-mentioned requirements for compact heat exchangers, this undesirable phenomenon has become even more pronounced.

As a countermeasure, a method has been proposed in which the surface of the aluminum fin is subjected to a hydrophilic surface treatment to form a thin film of condensed water and allow it to flow up.

[Problems to be Solved by the Invention] However, the wood-philic nature of the fin surface treated with hydrophilic surface treatment prevents dirt from adhering during the manufacturing process of the heat exchanger, and from entering the air during use as an air conditioner. It gradually decreases due to the adhesion of existing dust, sand, oil, etc., leading to an increase in ventilation resistance. Even if a commercially available cleaning agent is used to remove dirt adhering to the surface, the hydrophilicity of the fin surface cannot be sufficiently restored.

In view of these circumstances, an object of the present invention is to provide a cleaning agent for aluminum heat exchangers for air conditioning, and in particular, to provide a cleaning agent that restores the degraded hydrophilicity of the surface of aluminum fins subjected to hydrophilic surface treatment. It is something.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors first conducted extensive research into the causes of a decrease in hydrophilicity. Dust inside, sand dust,
It has been found that adsorption of polyvalent metals (such as calcium, magnesium, and iron) contained in sea salt particles to the hydrophilic treated fin surface is a significant cause that cannot be ignored.

Therefore, the development of a cleaning agent that can remove these causes of hydrophilicity deterioration became a research topic, and as a result of intensive study of the ingredients of the cleaning agent, we were able to complete a cleaning agent that has the desired ability to restore hydrophilicity. did it.

That is, the present invention provides (a) a polyvalent metal ion sequestering agent, (b)
) A surfactant, and (c) an alkali builder, which is a cleaning agent for aluminum heat exchangers for air conditioning.

(a) The polyvalent metal ion sequestering agent used in the present invention includes, for example, alkali metal salts of aminopolycarboxylic acids;
Examples include alkali metal salts of aminocarboxylic acids, alkali metal salts of polyphosphoric acid, alkali metal salts of aluminosilicate carboxylic acids, alkali metal salts of carboxylic acids, polyamine compounds, and amine compounds. Or use two or more types of compounds.

(b) As the surfactant, one or more of anionic surfactants and nonionic surfactants are used as appropriate.

(e) Examples of the alkali builder include carbonates, phosphates, silicates, and borates, and one or more of these may be used.

Next, each component of the cleaning agent and its main action will be described below.

(a) First component: The polyvalent metal ion sequestering agent has the effect of preventing the polyvalent metal ions from re-adhering to the fin surface by reacting with and sealing the polyvalent metal ions.

These components have already been described, but to explain more specifically: ■ Alkali metal salt of aminopolycarboxylic acid As niaminopolycarboxylic acid, ethylenediaminetetraacetic acid (
EDTA), cyclohexadiaminetetraacetic acid (cy
DTA), glycol ether diamine tetraacetic acid (G
IEDTA), diethylenetriaminepentaacetic acid (DT
PA), triethylenetetraminehexaacetic acid (TTI
IA), Nitrilotriacetic acid (NTA), Tetraethylenepentamineheptaic acid If (TPIIA), Hydroxyethylethylenediaminetriacetic acid (IIEDTA)
, ethylenediaminetetrapropionic acid (EDTP)
, diaminocyclohexanetetraacetic acid (DCTA), and the like. Alkali metals include sodium, potassium,
There's lithium. Among these, sodium ethylenediaminetetraacetate and sodium nitrilotriacetate are preferred.

(2) Alkali metal salts of aminocarboxylic acids Niaminocarboxylic acids include α-alanine, glutamic acid, glycine, iminodiacetic acid, picolinic acid, and cysteine. Alkali metals include sodium, potassium, and lithium, and sodium salts are preferred.

■ Alkali metal salts of polyphosphoric acid: Polyphosphoric acids include birophosphoric acid, tripolyphosphoric acid, tripolyphosphoric acid, and chain polyphosphoric acid.
Examples include tetrapolyphosphoric acid, and cyclic polyphosphoric acids include trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, and the like.

Alkali metals include sodium, potassium, and lithium. Among these, sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, and sodium hexametaphosphate are preferred.

■ Aluminosilicates: Aluminosilicates include natural zeolites and synthetic zeolites containing alkali metals.

■ Alkali metal salts of carboxylic acids: Examples of carboxylic acids include citric acid, malic acid, oxalic acid, tartaric acid, lactic acid, salicylic acid, sulfosalicylic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, benzoic acid, formic acid, and acetic acid. , acetylacetone, etc. Alkali metals include sodium,
Contains potassium and lithium. Among these, sodium citrate, sodium malate, sodium oxalate, sodium tartrate, and sodium lactate are preferred.

■ In addition to the above components, polyamine compounds such as ethylenediamine (En) and diethylenetriamine (Die
n)) Lyaminotriethylamine (Tren)
Amine compounds such as triethylenetetramine (Trlen), tetraethylenepencunamine (Tctrcn), pentaethylenehexamine (Pcntcn), diaminopropane (DAP), triaminopropane (TAP), triethanolamine (TEA), diamino Diethyl sulfide (DS), thiourea, thiosemicarbamide, 2,2'-dipyridyl, l,10-phenanthrine, 8-oxyquinoline-5-sulfonic acid (II
It may also contain a polyvalent metal ion sequestering agent such as Qs).

(b) Second component: The surfactant lowers the interfacial tension between the contaminant and the fin surface, penetrates between them, separates the contaminant from the fin surface, and has the effect of emulsifying and separating the dyed material. do.

Specifically, these components include sodium alkylbenzenesulfonate, sodium alkylsulfate, triethanolamine alkylsulfate, and sodium alkylnaphthalenesulfonate A1 as anionic surfactants.
Sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, sodium alpha olefin sulfonate, sodium alkyl diallyl ether sulfonate, alkyl phosphate, sodium fatty acid, carboxylic acid type polymer activator Among them, sodium alkylbenzene sulfonate, sodium alkyl sulfate, triethanolamine alkyl sulfate, sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, and sodium alpha olefin sulfonate are preferred. Polyoxyethylene alkyl ether (
Examples include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene higher alcohol ether. ), polyoxyethylene alkyl allyl ether (polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, etc.), polyoxyethylene derivatives, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, etc. The HLB of the surfactant is preferably 9 or more and 20 or less.

(c) Third component: Alkali builder lowers the interfacial tension, makes the liquid alkaline, and maintains it,
It has the effect of facilitating the separation of substances formed on the fin surface from the surface. It also has the effect of preventing the detached t1j dye material from being reattached to the tube.

Specifically speaking about these ingredients, carbonates include sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, etc., and phosphates include sodium orthophosphate, sodium birophosphate, potassium pyrophosphate, and tripolyphosphate. There are silicates such as sodium metasilicate, sodium sesquisilicate, and sodium orthosilicate, and borates such as borax. Among these, sodium carbonate, sodium tripolyphosphate, sodium metasilicate, sodium orthosilicate, and borax are preferred.

In addition to the above-mentioned components, it is also possible to include sodium sulfate, carboxymethyl cellulose, etc. as a builder, and to use ethanol, propylene glycol, etc. as a solubilizing agent.

The relative proportions of each component in the cleaning agent, by weight, are (a):
(b): (e) -1~100: 10~to
o: 1 to 50 mouths is desirable.

The amount of the cleaning agent of the present invention added to the cleaning solution during use can be determined as appropriate depending on the number of aluminum heat exchangers to be cleaned, the degree of tri-staining, the cleaning method, and the effective whitening concentration of each component in the cleaning agent. However, 0.05 to 200 g/cross is preferable.

In addition, the pH of the cleaning solution during use is 5 to 13, preferably
7 to 12.

[Example] The present invention will be explained in more detail by giving examples below.

Example Industrial pure aluminum (A1
050 H22) After degreasing, cleaning and phosphoric acid chromate treatment, a hydrophilic paint containing a carboxyl group as a hydrophilic functional group was applied to create a hydrophilic surface treated fin shrine (water resistant) with a hydrophilic film layer of 18m thick. The contact angle with the material was 5°). Next, the hydrophilicity of the hydrophilic surface-treated fin material was determined by
The contact angle with water was reduced to 35° using a dry/wet alternating tester with a 2-minute water immersion = 6-minute cold air drying cycle. The fin materials with reduced hydrophilicity were immersed in the cleaning solutions shown in Tables 1 and 2 for 10 minutes, and then washed with water.The contact angle with the water was determined as A11J, and the cleaning effect was evaluated.

◯ indicates good (contact angle 15'' or less), Δ indicates somewhat good (contact angle 15-30'), and X indicates poor (contact angle greater than 30°).

The meanings of the abbreviations used in Tables 1 and 2 are shown below.

EDT^; Sodium ethylenediaminetetraacetate NT
A: Sodium nitrilotriacetate^13S: Sodium alkylbenzene sulfonate (Neoperex F-25, manufactured by Kako) AS: Sodium alkyl sulfate (Emar 0, manufactured by Kako),! (On ■: Polyoxyethylene nonyl phenyl ether 11 [, B Lo, 8 (, iE Kou Emulgen 9
0G) 3 (ON): Polyoxyethylene nonylphenyl ethyl IILB 14.5 (Emulgen 91 manufactured by Kako Co., Ltd.
3) Calculation ion ■: Polyoxyethylene nonylphenyl ether IILB J7.5 (Emulgen 9 manufactured by IE Kogyo Co., Ltd.
35) Charcoal #Na: Sodium carbonate Na metasilicate: Storium metasilicate TSP: Sodium orthophosphate 5TPr' Nitripolyphosphate Major thorium glutamate N
a: Sodium glutamate Sodium citrate: Sodium citrate AI (1m example) Table 2 (comparative example) Procedures 11 Seiji Miken (voluntary) November 16, 1988

Claims (1)

[Claims] A cleaning agent for aluminum heat exchangers for air conditioning, comprising (a) a polyvalent metal ion sequestering agent, (b) a surfactant, and (c) an alkali builder.