JP2001164400A - Electrolytic peeling agent for phenolic resin and electrolytic peeling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrolytic peeling agent for a phenolic resin which can rapidly peel the phenolic resin applied on a metallic surface, is further capable of separating and removing the phenolic resin by circulating the peeling liquid with a pump, is continuously usable and is improved in working environmental and waste water treating properties, and to provide an electrolytic peeling method. SOLUTION: The electrolytic peeling agent for the phenolic resin containing 5 to 500 g/L >=1 kind of alkali hydroxides, 1 to 300 g/L >=1 kind of organic amines, and further, 1 to 300 g/L >=1 kind of organic acids and/or their salts and 0.01 to 50 g/L >=1 kind of surfactants, and the electrolytic peeling method is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic stripping solution for a phenolic resin applied on a metal and an electrolytic stripping method.

[0002]

2. Description of the Related Art Phenol resins have excellent coating properties on metals, are inexpensive and have excellent heat resistance, electrical insulation, abrasion resistance, weather resistance, etc., and are widely used as paints on metals. Have been. They are also used in the manufacturing process of foot-operated brake devices and automatic transmissions related to automobiles. However, when a phenol resin is applied to a metal surface, a defective product is generated due to an uneven coating film, an adhesion defect, or the like. In order to regenerate the defective product or the jig used repeatedly, a step of removing the phenol resin is provided. Conventionally, in this stripping step, a stripping solution containing a large amount of a chlorine-based solvent or an acidic or alkaline stripping solution containing an aqueous organic solvent has been used, and the phenol resin coating film has been stripped by a treatment method such as immersion or spraying. .

[0003]

However, such a conventional technique has a problem that it contains a harmful chlorine-based solvent or a highly flammable solvent. Further, it takes a long time to completely remove the phenol resin. There was a problem with workability because of the need. In addition, since this resin dissolves and accumulates in the stripping solution, the solution has to be renewed in a short period of time, which not only has a problem that the cost becomes large, but also the aging waste liquid at the time of the renewal requires solvent or Because of the large amount of resin, wastewater treatment was difficult. Several methods have been tried to solve such problems, but there is a dilemma in which the running property and the wastewater treatment property decrease when the peeling property is improved, and until the above problems are overcome. There was no situation.

[0004] In view of the problems of the prior art, the present invention has been intensively studied for a release agent having low pollution and good productivity. As a result, in the prior art, the treatment method was merely immersion in a stripping solution. The present invention has succeeded in solving various conventional problems by the electrolytic stripping method which has not been attempted at all. ADVANTAGE OF THE INVENTION According to this invention, resin can be peeled in a short time, the peeled resin can be easily separated and removed, running can be performed for a long time, and the cost has been successfully reduced. Further, according to the present invention, since no chlorine-based solvent is contained and the resin hardly dissolves in the stripping solution, the problems of the working environment and the wastewater treatment property are solved.

That is, according to the present invention, the phenol resin can be peeled off in a short time and can be used for a long time.
An object of the present invention is to provide an electrolytic stripping solution for a phenolic resin and an electrolytic stripping method with improved wastewater treatment properties.

[0006]

The electrolytic stripping solution for a phenolic resin according to the present invention comprises an alkali hydroxide, an organic amine,
It is composed of a combination of an organic acid and / or a salt thereof and a surfactant. Further, the method for electrolytically stripping a phenolic resin coating film of the present invention comprises immersing the phenolic resin applied on the metal surface as a cathode or an anode in the above-mentioned electrolytic stripping solution and treating with a current density of 0.5 to 50 A / dm ² . The resin is stripped by electrolytic treatment under the conditions, and the stripped solution is circulated to separate and remove the stripped resin, followed by continuous processing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The electrolytic stripping solution for phenolic resin and the electrolytic stripping method of the present invention will be described in detail below. The phenolic resin according to the present invention is a phenolic resin such as a phenol-formalin resin (phenol resin), a cresol-formalin resin, a modified phenol resin, a phenol-furfural resin, and a resorcin resin.

[0008] The alkali hydroxide of the present invention is a main component that corrodes the resin, imparts conductivity to the stripping solution, and releases and removes the resin by the action of hydrogen and oxygen gas generated by electrolysis. Examples thereof include alkali metal hydroxides such as lithium hydroxide, potassium hydroxide, and sodium hydroxide. These are effective when used at a concentration of 5 to 500 g / L, and particularly preferably 30 to 300 g / L.

Although the action of the organic amine used in the present invention is not necessarily clear, it is a component that cuts the cross-linking of the resin polymer to form a monomer, and has an effect of accelerating peeling by causing cracks in the resin. It is considered to be obtained. These organic amines can include aliphatic and aromatic mono- or polyamines containing at least one amino group, their ammonium salts, (poly) alkylene polyamines, alkanolamines, and the like.

The most suitable organic amines include methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, pentylamine, isopentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, Methylethylamine, N-ethylisobutylamine, trimethylamine, triethylamine,
Primary, secondary and tertiary amines such as N, N-dimethylpropylamine, N-ethyl-N-methylbutylamine, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetramethylammonium hydroxide , Ammonium salts such as tetraethylammonium chloride, tetraethylammonium hydroxide, etc. (poly) such as ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc. Alkylene polyamine, ethanolamine, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-
1,3-propanediol, ethyl monoethanolamine, diethanolamine, dimethylethanolamine,
Diethylethanolamine, butyldiethanolamine, 3-diethylamine-1,2-propanediol,
Examples thereof include alkanolamines such as triethanolamine and tris (2-hydroxypropyl) amine, and aromatic amines such as choline, aniline, toluidine, methylaniline, ethylaniline, diphenylamine and phenylenediamine. These are preferably used at a concentration of 1 to 300 g / L, more preferably 10 to 200 g / L.

The organic acid and / or salt thereof used in the present invention has the effect of improving the conductivity of the stripping solution and promoting the release of the resin by the auxiliary action of the alkali hydroxide. Examples of usable organic acids and / or salts thereof include aliphatic and aromatic mono- or polycarboxylic acids, oxycarboxylic acids, amino acids and the like, and also aliphatic and aromatic mono- or polysulfonic acids and the like, which are soluble in these acids. Salts, especially alkali metal salts, are included.

Examples of effective organic acids and / or salts thereof include formic acid, acetic acid, propionic acid, gluconic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and benzoic acid. Carboxylic acids such as acids, phthalic acid, tartaric acid, glycolic acid, lactic acid, ethylenediaminetetraacetic acid, glycine, diglycolic acid, citric acid, malic acid, glyceric acid and nitrilotriacetic acid and / or alkali metal salts thereof, and methanesulfonic acid And sulfonic acids such as ethanesulfonic acid, benzenesulfonic acid and toluenesulfonic acid and / or alkali metal salts thereof. These are preferably used at a concentration of 1 to 300 g / L,
More preferably, it is used at a concentration of 10 to 200 g / L.

The surfactant used in the present invention has the effect of promoting the action of the organic amine and accelerating the detachment of the resin from the material surface. As long as the surfactant has an osmotic action, any of anionic, cationic, amphoteric, and nonionic surfactants can be used, but anionic and nonionic surfactants are preferred. Examples of the anionic surfactant include a fatty acid soap surfactant, an alkyl sulfonate, an alkylbenzene sulfonate, an alkyl (or alkoxy) naphthalene sulfonate, an alkyl ether sulfonate, an alkyl sulfate ester salt, and polyoxyethylene. Alkyl ether sulfates, polyoxyethylene alkylphenol ether sulfates, alkylol sarcosine,
Alkyloyl sarcosinate, alkyl sulfoacetate,
Examples thereof include alkyl sulfocarboxylates, alkyl sulfosuccinates, dialkyl sulfosuccinates, and alkyl polyoxyethylene sulfosuccinates. The above salts include alkali metal salts, ammonium salts and the like. Nonionic surfactants include polyoxyalkylene alkyl ethers (or esters), polyoxyalkylene phenyl (or alkyl phenyl) ethers, polyoxyalkylene styrenated phenyl ethers, polyoxyalkylene bisphenol ethers, polyoxyethylene polyoxypropylene Block polymer, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene sorbite fatty acid ester, polyethylene glycol fatty acid ester, polyoxyalkylene glycerin fatty acid ester, polyoxyalkylene alkylamine,
Polyoxyalkylene condensate adduct of ethylenediamine, polyoxyalkylene fatty acid amide, polyoxyalkylene castor oil, polyoxyalkylene alkylphenyl formalin condensate, glycerin (or polyglycerin) fatty acid ester, pentaerythritol fatty acid ester, sorbitan mono (sesqui, Tri) fatty acid esters, higher fatty acid mono (di) ethanolamide, alkyl / alkyloamide, oxyethylenealkylamine and the like. The concentration is in the practical range of 0.01 to 50 g / L, and preferably 0.1 to 10 g / L.

Next, in the electrolytic stripping method of the present invention,
The object to be treated is immersed in the stripping electrolyte of the present invention as either an anode or a cathode and subjected to electrolytic treatment. The anode has a larger stripping effect. As the counter electrode, any material having conductivity and alkali resistance can be used.
Steel is preferred. The treatment temperature has a wide practical range, and it can be used at a low temperature or a high temperature. The current density of the electrolysis is 0.5 to 50 A / d.
m ² is preferred. Further, the resin that has been peeled off and dropped can be continuously used without any deterioration of the liquid because the peeling liquid is constantly circulated and can be easily separated and removed by passing through a filtering material such as an alkali-resistant net or a filter cloth. .

[0015]

EXAMPLES The effects of the present invention will be described below with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with appropriate modifications.

Examples 1 to 6 SUS304 stainless steel plate (50 × 100 × 0.3 m
m) was degreased and washed, and a sulfuric acid aqueous solution (100 g / L, 60 g
After activating for 5 minutes), 0.2 g of a phenol resin (D-22 manufactured by Oshika Shinko Co., Ltd.) solubilized with a solvent was evenly applied with a bar coater except for a part of the current-carrying part with the electrodes. ,
After drying at 120 ° C. for 15 minutes, a test piece was prepared. An electrolytic stripping solution containing 150 g / L of sodium hydroxide and 100 g / L of the organic amine shown in Table 1 were prepared, and the test piece was used as an anode in these electrolytic stripping solutions.
A stainless steel plate of SUS304 is immersed as a cathode,
Electrolytic treatment was performed at 5 ° C. and 5 A / dm ² , and the peeling time was measured. Table 1 shows the results.

Examples 7 to 8 The same method as in Examples 1 to 6 was applied to the electrolytic stripping solution shown in Table 1.
SUS304 stainless steel, using the test piece prepared in
Immersion as a positive electrode at 25 ° C, 5A / dm ^TwoCondition
And the stripping time was measured. Table 1 shows the results.
Show.

Examples 9 to 13 5 to 500 g / L of sodium hydroxide shown in Table 1, TMA
H (tetramethylammonium hydroxide) 1-300 g /
A test piece prepared in the same manner as in Examples 1 to 6 above was immersed in the electrolytic stripping solution L as an anode, and a SUS304 stainless plate was used as a cathode, and subjected to electrolytic treatment at 25 ° C. and 5 A / dm ² , The peel time was measured. Table 1 shows the results.

Examples 14 to 20 Potassium hydroxide 120 g / L, TMAH 70 shown in Table 1
g / L aqueous solution to which an organic acid or an organic acid salt and a surfactant were added to prepare an electrolytic stripping solution, and a test piece prepared in the same manner as in Examples 1 to 6 above was used as an anode, and SUS
The 304 plate was immersed as a cathode, subjected to electrolytic treatment at 25 ° C. and 5 A / dm ² , and the peeling time was measured. Table 1 shows the results.

Examples 21 to 27 SPCC steel sheets were added to an electrolytic stripping solution of 80 g / L of lithium hydroxide and 100 g / L of ethylenediamine and an electrolytic stripping solution to which an organic acid or an organic acid salt and a surfactant were added as shown in Table 1. (50 × 100 × 0.3 mm) was immersed in a test piece prepared by the same method as in Examples 1 to 6 above as an anode and an SPCC steel plate as a cathode, and the temperature was 20 to 90 ° C.
The electrolytic treatment was performed under the current density range of 0.5 to 50 A / dm ² , and the peeling time was measured. Table 1 shows the results.

Example 28 Examples 1-5 were applied to an electrolytic stripping solution containing 120 g / L of sodium hydroxide and 70 g / L of TMAH and an electrolytic stripping solution containing 80 g / L of sodium gluconate and 5 g / L of Demol N added thereto.
Using a test piece prepared in the same manner as
04 stainless steel plate as a cathode, immersion at 25 ° C, 5A /
The electrolytic treatment is performed under the condition of dm ² until the film is completely peeled off. While repeating this, the electrolytic stripping solution was circulated by a pump, the running was continued while the separated resin was separated and removed by a stainless mesh, the stripping time was measured, and the degree of deterioration of the stripping property was evaluated. 500 test pieces were treated per liter of the electrolytic solution, and the liquid was colored yellowish brown and hardly changed, and the peeling time was the same as the initial time (4 minutes) and did not change at all.

Comparative Examples 1 to 6 Test pieces prepared in the same manner as in Examples 1 to 6 were immersed in a stripping solution shown in Table 1 under predetermined conditions, and the stripping time was measured.
Table 1 shows the results.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

The electrolytic stripping solution and the electrolytic stripping method of a phenolic resin according to the present invention exhibit a remarkably excellent stripping effect as compared with the prior art, and enable continuous use by separating and recovering the stripped phenolic resin. . Furthermore, since the amount of resin mixed into the stripping solution is extremely small and does not contain any chlorine-based solvent, wastewater treatment is easy, and wastewater treatment costs can be reduced.
It is excellent in reducing wastewater treatment of washing water, and is extremely useful in industry.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 BB20Z BB81Z CA02 CA18 CA23 CA32 DB01 DC11 EA06 EB32 EC01 EC07 EC35 EC54 4F301 AA22 AD10 BA02 BA12 BA22 BF06

Claims (7)

[Claims] 1. An electrolytic stripping solution for a phenolic resin, which comprises one or more alkali hydroxides. 2. The electrolytic stripping solution for phenolic resin according to claim 1, further comprising one or more organic amines. 3. The electrolytic stripping solution for phenolic resin according to claim 1, further comprising one or more of an organic acid and / or a salt thereof. 4. The method according to claim 1, wherein one or more of the alkali hydroxides is from 5 to 500.
g / L, at least one of organic amines at a concentration of 1 to 300 g / L, and at least one of organic acids and / or salts thereof at a concentration of 1 to 300 g / L. The electrolytic stripping solution for phenolic resin according to 1. 5. The method according to claim 1, wherein one or more of the surfactants is 0.01 to 50.
2. The composition of claim 1, further comprising g / L.
The electrolytic stripping solution for a phenolic resin according to any one of claims 1 to 4. 6. A phenolic resin applied on a metal surface is immersed in the electrolytic stripping solution for phenolic resin according to claim 1 as an anode or a cathode.
A method for electrolytically peeling off a phenolic resin coating, comprising electrolytically removing the phenolic resin coating at a current density of A / dm ² . 7. The electrolytic stripping method according to claim 6, wherein the phenolic resin stripped by the electrolytic stripping method is continuously pump-circulated with the electrolytic stripping solution for phenolic resin according to any one of claims 1 to 5. A method for continuous electrolytic stripping of a phenolic resin coating film, which includes separating and removing.