JPH1068000A - Cleaning composition for coating material pipe and cleaning of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cleaning composition for a coating material pipe, improved in safety and handling by including formic acid, potassium oleate, N- methylpyrrolidone, etc., in a specific proportion therein without containing methylene chloride. SOLUTION: This cleaning composition comprises (A) 1-10wt.% formic acid and (B) 0.5-5wt.% potassium oleate and further (C) the balance of a single solvent of N-methylpyrrolidone or a mixed solvent containing >=20wt.% N- methylpyrrolidone and is obtained by making up the total to 100wt.%. Furthermore, the mixed solvent is composed of the N-methylpyrrolidone and a diester of a 2-6C dibasic acid (e.g. dimethyl adipate) and the content of the N- methylpyrrolidone is preferably >=20wt.%. A coating material pipe is preferably cleaned with the resultant composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pipe for installing a paint mixing chamber and feeding the paint therefrom to a spraying chamber, or a paint pipe such as a paint circulating supply device. The present invention relates to a composition for effectively removing and cleaning deposits such as dust and a method for removing the deposits.

[0002]

2. Description of the Related Art In a large painting factory for vehicles, various equipments, etc., when deposits remain in paint pipes such as a paint feeding pipe and a paint circulating supply apparatus, sometimes the paint to be coated is interlocked with the circulating paint. It adheres to the surface, causing poor painting, and repairing it requires a lot of time and cost. for that reason,
It is common to clean paint tubing regularly or as needed. As a washing method in this case, a method of circulating and washing a thinner for washing for 2 to 4 weeks, a high-pressure water washing method, a pig washing method, and the like have been performed, but the washing effect is insufficient or the piping is Since it is long, has many bent portions, and requires pressure resistance of the piping, its application is limited. or,
A method of mixing and circulating amines and organic acids in a chlorine-based solvent is known, but the fixed paint in the pipe was not sufficiently removed and the cleaning effect was not sufficient. Also, as a similar chemical cleaning method, a strong alkaline solution is heated and circulated,
A method of removing paint may also be used (Japanese Patent Laid-Open No.
However, since the cleaning liquid is a strong alkaline liquid and the effect of removing the paint is not sufficiently exhibited unless the cleaning liquid is treated at a high temperature, a heating facility is required. If the liquid leaks, there is a danger of a serious accident. As a countermeasure, formic acid, based on methylene chloride,
Further, a cleaning composition to which a surfactant has been added has been proposed (Japanese Patent Laid-Open No. 5-185045).

[0003]

The cleaning composition obtained by mixing formic acid and a surfactant with methylene chloride has been considerably improved in cleaning effect and has been evaluated to some extent. Recently, however, methylene chloride has been used. Suspected of being transformed into carcinogenic substances in the surrounding environment, the use of which has become extremely restricted.

The present inventors have made a composition for safely and efficiently cleaning which does not contain methylene chloride, and a method for cleaning the composition.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for effectively removing and washing deposits such as paints, pigments and dust attached to paint pipes. A composition comprising potassium acid, N-methylpyrrolidone and, if necessary, a dibasic acid diester having 2 to 6 carbon atoms, and further adding another organic solvent as needed, does not contain methylene chloride. It has been found that the peeling is good and the cleaning power of the paint pipe is excellent, and the present invention has been accomplished.

That is, the present invention provides formic acid of 1 to 10 parts by weight,
A paint containing 0.5 to 5 parts by weight of potassium oleate, N-methylpyrrolidone and, if necessary, a dibasic acid diester having 2 to 6 carbon atoms and, if necessary, another organic solvent to make the whole 100% by weight. A cleaning composition for removing deposits in a pipe, and a method for cleaning a paint pipe using the composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Formic acid used in the present invention has an effect of accelerating the removal of deposits, and is contained in the composition in an amount of 1 to 10% by weight, preferably 2 to 5% by weight. 1% by weight formic acid
If it is less than 10%, the effect will not be sufficiently exhibited.
Even if the amount is more, the improvement of the cleaning effect is not remarkable. Formic acid is usually marketed as a product partially containing water,
In a system where N-methylpyrrolidone coexists, there is no problem even if this water is present in the composition. The formic acid compounding amount is converted to a concentration, and is added as formic acid so as to account for 1 to 10% by weight of the composition.

[0008] The potassium oleate used in the present invention has an effect of accelerating penetration into the paint or pigment to which the cleaning composition has adhered, and 0.5 to 5% by weight, preferably 1 to 3% by weight in the composition. It is blended in the range. If the content of potassium oleate is less than 0.5% by weight, the effect of removing deposits in the paint pipe is not sufficient, while if it exceeds 5% by weight, the cleaning effect is sufficient, but the effect is not good for the added amount. It is disadvantageous economically. Potassium oleate is commercially available as an aqueous solution of 10 to 20% by weight, and the aqueous solution may be used for the purpose of the present invention. The compounding amount is converted to a concentration, and added so as to account for 0.5 to 5% by weight of the composition as potassium oleate.

The N-methylpyrrolidone used in the present invention is
It acts as a medium for dissolving the attached paint and pigment, and also as a medium for dissolving the formic acid and potassium oleate, and plays an important role in removing deposits in the paint piping. The amount of N-methylpyrrolidone in the composition is at least 20% by weight, preferably at least 25% by weight, and if it is less than 20% by weight, the ability to remove the original deposits is undesirably small.

[0010] The combination of formic acid, potassium oleate and N-methylpyrrolidone is sufficient to remove deposits in paint tubing. However, N-methylpyrrolidone is usually expensive and often poses a problem from a practical and economical standpoint. Therefore, a part of N-methylpyrrolidone can be used in place of a dibasic acid diester having 2 to 6 carbon atoms, and a part can be used in place of another organic solvent.

The dibasic acid diester having 2 to 6 carbon atoms used in the present invention, like N-methylpyrrolidone, has a great effect of dissolving paint and pigment adhering to the paint pipes, and has a large penetrating effect. The dibasic acids having 2 to 6 carbon atoms include oxalic acid, maleic acid, succinic acid, glutaric acid, and adipic acid, and dimethyl and / or diethyl esters thereof are used. The preferred compounding amount of the dibasic acid diester is 20% by weight or more in the composition.

Other organic solvents in the present invention are organic solvents except N-methylpyrrolidone and dibasic acid diesters having 2 to 6 carbon atoms, and dissolve, soften, swell, and peel paints and pigments deposited in paint pipes. The one that has the action of Examples thereof include alcohol solvents such as ethylene glycol, benzyl alcohol, methoxyethanol and ethoxyethanol, methyl ethyl ketone, diisobutyl ketone, cyclohexanone, ketone solvents such as acetophenone, ester solvents such as γ-butyrolactone, acetonitrile, propionitrile, Examples include nitrogen-containing solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, sulfur-containing solvents such as dimethylsulfoxide, and aromatic solvents such as ethylbenzene, cumene, p-cymene, and naphthalene. These organic solvents are arbitrarily selected depending on the situation, and two or more kinds can be used in optional combination.

[0013] Although not an essential component of the cleaning composition in the present invention, commercially available formic acid or potassium oleate is an aqueous solution. Even if it is used as an aqueous solution as it is, it has almost no adverse effect on the cleaning effect.

When the present composition is used to remove and clean deposits in the paint pipes, the present composition is circulated using a circulation device. As the circulating device, it is preferable to install a strainer for removing deposits such as paint and dust removed from the piping.

The circulation time of the composition is appropriately determined in consideration of the facilities of the paint piping system, the degree of contamination in the piping, and the like, but is usually 5 to 24 hours. During this time, the strainer is replaced as appropriate, and the cleaning time is usually determined according to the degree of contamination. Further, when the paint pipe is extremely contaminated, the composition may be replaced with a suitable one. The circulation is usually at a flow rate of 0.5 to 4 m / sec, preferably 1 to 3 m
Per second. By circulating the present composition, deposits on the pipes and the like are removed and washed, and thereafter, the paint is circulated and restored using the cleaning thinner and then the thinner for dilution.

In addition, depending on the paint pipe, washing with an acid after washing with the present composition is effective for the purpose of removing rust at the lower portion of the deposit and removing inorganic components in the deposit attached to the paint pipe. There are cases. In this case, after passing through an acid washing step, a neutralizing step, a rust prevention step, and a water displacement step, the washing thinner and the thinner for dilution are circulated and recovered by a known method.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples.

[Cleaning composition] A cleaning composition having the following composition was prepared.

[0019]

[Table 1]

(Test of peelability of coating film) Preparation of test piece: A mild steel test piece of 1 × 30 × 50 mm was immersed in paint at room temperature, drained naturally, and then dried and cured. Paint used in the test: Baking type melamine resin paint; Nippon Paint Co., Ltd., Olga Select 120 (trade name) Phthalic acid resin paint; Nippon Paint Co., Ltd., Unipack 200 (trade name) Synthetic resin paint; Nippon Paint Hi-Tex 500 (trade name) manufactured by Co., Ltd. Dry curing condition: baking-type melamine resin paint is 30 minutes at 110 ° C., and others are 8 hours at room temperature. Peelability test method: 100 mL beaker, cleaning composition of the present invention Alternatively, a comparative cleaning composition was added, the above-prepared test piece was suspended in the liquid, and the liquid was stirred with a magnetic stirrer, and the time until the coating film was almost completely peeled off was observed. The results are shown in Table 2.

From these results, it can be understood that the cleaning composition of the present invention is excellent in the peelability of the coating film.

[0022]

[Table 2]

(Fixed Paint Washing Test) In an automobile factory, a part of a pipe (1 inch inner diameter × 500 mm length) to which the paint was fixed was cut out and used for about 5 years. The test tube was connected to a test circulation device in a laboratory (a chemical solution holding amount of 10 L, a circulation amount of 36 L / min), and the test tube was circulated for 3 hours using the cleaning composition.

Remove the test tube and add 3 L of tap water.
After passing through the test tube at a rate of 2 minutes per minute, the state of the inner surface of the test tube was observed. The results are shown in Table 3.

[0025]

[Table 3]

[0026]

EFFECTS OF THE INVENTION By using the paint pipe cleaning composition and the cleaning method of the present invention, it is possible to effectively remove deposits such as paints, pigments, dust and the like adhered in the paint pipe. As a result, even when the paint pipe is reused, coating failure due to adhesion of deposits on the surface of the paint does not occur, and it is possible to save much time and cost for repairing the paint. Since the cleaning composition of the present invention does not contain methylene chloride, it is highly safe and can be handled with ease.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C11D 7/50 C11D 7/50

Claims (4)

[Claims] 1. A mixed solvent containing 1 to 10% by weight of formic acid and 0.5 to 5% by weight of potassium oleate, with the balance being a single solvent of N-methylpyrrolidone or at least 20% by weight of N-methylpyrrolidone. And 100% by weight of the total composition for cleaning paint piping. 2. The mixed solvent comprises N-methylpyrrolidone and a dibasic acid diester having 2 to 6 carbon atoms, wherein the content of N-methylpyrrolidone is at least 20% by weight.
A cleaning composition for paint piping as described in the above. 3. The mixed solvent comprises N-methylpyrrolidone, a dibasic acid diester having 2 to 6 carbon atoms and another organic solvent, and the content of each of the N-methylpyrrolidone and the dibasic diester is at least 20% by weight. The cleaning composition for paint piping according to claim 1, which is: 4. A method for cleaning a paint pipe, comprising using the composition according to claim 1, 2, or 3.