JP2013107931A - Cleaning liquid for aqueous coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning liquid for an aqueous coating, which contains almost no organic solvent component, can clean an aqueous coating effectively even in a small amount, and exhibits little bubbling of its waste water.SOLUTION: The cleaning liquid for an aqueous coating is prepared by mixing 100 parts by weight of water with 0.01 to 7.00 parts by weight of a polyether modified siloxane and 0.5 to 10.0 parts by weight of an alkanolamine. The polyether modified siloxane used for the cleaning liquid for an aqueous coating has a structure in which an ethyleneoxy group and a propyleneoxy group are ether-bonded to a specific siloxane skeleton.

Description

  The present invention relates to a cleaning liquid for washing away a water-based paint adhering to a painting apparatus, a painting tool, and a paint pipe.

  In a factory or the like where water-based paint is applied, it is necessary to continuously apply the same color or different colors using the same apparatus. In such a case, before coating with the next paint, it is necessary to clean and remove the previous paint adhering to the painting equipment or paint pipe. In particular, in an automated painting factory, the products to be coated flow continuously, and the remaining paint must be washed in a short time to supply the next paint. Therefore, the cleaning liquid is required to have a cleaning ability that provides a predetermined cleaning effect in a short time.

  Conventionally, a cleaning liquid mainly composed of water, a hydrophilic organic solvent, an amine as a pH adjuster, or the like has been used as the cleaning liquid for water-based paints (Patent Document 1). Moreover, in order to improve the detergency and reduce the content of the hydrophilic organic solvent, a cleaning liquid to which a surfactant is added has been devised (Patent Document 2). In addition, in order to eliminate the foaming problem in the wastewater treatment process etc., a detergent added with a specific surfactant having acetylene glycol as a skeleton has been developed. (Patent Document 3).

JP 2000-290544 A JP-A-10-192768 JP 2008-266649 A

  However, since all of the above conventional cleaning liquids have an organic solvent as a main component of the cleaning component, if the organic solvent is reduced, a good cleaning ability cannot be exerted on the dried water-based paint. There was a problem that the load was large.

  The object of the present invention is to eliminate the above-mentioned problems of conventional cleaning liquids for water-based paints, and to clean water-based paints effectively even in small amounts without containing (or hardly containing) organic solvent components. It is to provide a clean water-based paint cleaning liquid.

  Of the present invention, the invention described in claim 1 is an aqueous paint cleaning liquid for cleaning an aqueous paint, and 0.01 to 7.00 parts by weight of polyether-modified siloxane with respect to 100 parts by weight of water. And 0.5 to 10.0 parts by weight of alkanolamine are mixed.

  The invention described in claim 2 is the invention described in claim 1, characterized in that a surfactant is mixed.

  The cleaning liquid for aqueous paint according to claim 1 can smoothly remove the aqueous paint from the object to be cleaned and can easily dissolve (or disperse) the removed paint. It is possible to effectively prevent a situation where it adheres again to the object to be cleaned. In addition, the cleaning liquid for water-based paint according to claim 1 has very little foaming of waste water. Therefore, according to the washing | cleaning liquid for water-based paints concerning Claim 1, it becomes possible to wash | clean a to-be-washed object very efficiently. In addition, since the cleaning liquid for water-based paint according to claim 1 has a simple composition, it is easy to prepare and has a very low content of VOC (Volatile Organic Compounds), and therefore does not adversely affect the environment.

  The cleaning liquid for water-based paints according to claim 2 can develop a higher detergency with the added surfactant.

It is explanatory drawing which shows the evaluation method of a cleaning characteristic.

  The cleaning liquid for water-based paint according to the present invention is obtained by mixing 0.01 to 7.00 parts by weight of polyether-modified siloxane and 0.5 to 10.0 parts by weight of alkanolamine in 100 parts by weight of water. is there.

  The polyether-modified siloxane has a structure represented by the following chemical formula (Chemical Formula 1). In order to develop a high detergency, it is preferable to use one having a molecular weight of about 500 to 10,000. Moreover, in order to express a high detergency, it is preferable to use what adjusted so that (alpha) + (beta) + (gamma) may be 3 or more and 150 or less. In addition, it is particularly preferable to use so-called polyether-modified organopolysiloxane among such polyether-modified siloxanes.

なお、式中、Ｒ_１〜Ｒ_７は、それぞれ、炭素数が１〜６個のアルキル基であり、α，β，γは、それぞれ、１以上の整数である。また、Ｅ０は、エチレンオキシ基であり、Ｐ０は、プロピレンオキシ基である。さらに、δ，εは、それぞれ、０以上の整数であり、δ，εともに０とはならないように選択される。加えて、Ｅ０とＰ０との結合状態は、ランダムであってもブロックであっても良く、その結合順序は限定されない。

In the formula, R _{1 to} R ₇ are each an alkyl group having 1 to 6 carbon atoms, and α, β, and γ are each an integer of 1 or more. E0 is an ethyleneoxy group, and P0 is a propyleneoxy group. Furthermore, δ and ε are integers of 0 or more, respectively, and are selected so that neither δ nor ε is 0. In addition, the coupling state between E0 and P0 may be random or block, and the coupling order is not limited.

  The polyether-modified siloxane described above needs to be mixed in an amount of 0.01 to 7.00 parts by weight, preferably 0.01 to 5.00 parts by weight, with respect to 100 parts by weight of water as the main component. When the content of the polyether-modified siloxane is less than 0.01 parts by weight, the cleaning power of the aqueous paint cleaning liquid is reduced, which is not preferable. Moreover, even if the content of the polyether-modified siloxane exceeds 7.00 parts by weight, the detergency will not reach its peak and improve, not only the economics at the time of production will deteriorate, but also the stability of the aqueous paint cleaning liquid will be improved. Since it gets worse, it is not preferable. From the viewpoint of detergency and economy, the content of the polyether-modified siloxane is more preferably 0.01 parts by weight or more and 0.10 parts by weight or less.

  On the other hand, as alkanolamine, monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine, morpholine, piperazine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N -(2-Aminoethyl) ethanolamine, N-methylethanolamine, N-methyldiethanolamine, N-ethylethanolamine, N-butylethanolamine, N-butyldiethanolamine, N-tertiarybutylethanolamine, N-tertiary Suitable for butyldiethanolamine, N- (2-aminoethyl) isopropanolamine, N, N-diethylisopropanolamine, ethylamine, diethylamine, triethylamine, trimethylamine, propylamine, butylamine, etc. It is possible to have. Among them, those that do not fall within the EU definition of VOC (Gothenburg Protocol 1999), such as DIPA, triisopropanolamine, diethanolamine, triethanolamine, diisopropanolamine, N- (2-aminoethyl) -2-aminoethanol Is more preferable, and diisopropanolamine is particularly preferable.

  The above alkanolamine is preferably mixed in an amount of 0.5 to 10.0 parts by weight with respect to 100 parts by weight of water as the main component. If the alkanolamine content is less than 0.5 parts by weight, the cleaning power of the aqueous paint cleaning liquid is reduced, which is not preferable. On the other hand, even if the content of alkanolamine exceeds 10.0 parts by weight, the detergency has not reached its peak and does not improve, the amount of VOC in the cleaning liquid increases, and economics at the time of manufacture and water-based paint This is not preferable because the stability of the cleaning liquid is deteriorated. The alkanolamine content is more preferably 0.5 parts by weight or more and 5.0 parts by weight or less, and further preferably 0.5 parts by weight or more and 2.0 parts by weight or less.

  In addition, the water-based paint cleaning liquid according to the present invention is more preferably a mixture of a surfactant. The type of the surfactant is not particularly limited, but those having ethylene oxide (or propylene oxide) in the side chain are preferable, and those having an acetylene glycol skeleton are more preferable. Among these, those having a structure of the following chemical formula (Chemical Formula 2) (for example, polyoxyethylene acetylenic glycol ether) are particularly preferable.

なお、上式において、Ｒ１〜Ｒ４ はアルキル基（好ましくは炭素数１〜５のアルキル基）を示し、ｍおよびｎはエチレンオキサイドの付加モル数（好ましくは０〜３０、より好ましくは２〜８、特に好ましくは２〜６の整数）を示す。

In the above formula, R1 to R4 represent an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms), and m and n are added moles of ethylene oxide (preferably 0 to 30, more preferably 2 to 8). , Particularly preferably an integer of 2 to 6.

  The surfactant content is preferably mixed in an amount of 0.1 to 10.0 parts by weight with respect to 100 parts by weight of water, which is the main component. If the amount of the surfactant mixed is small, the cleaning power of the cleaning liquid decreases, which is not preferable. On the other hand, if the amount of the surfactant mixed is large, foaming of the waste liquid increases, which is not preferable.

  Further, the cleaning liquid for water-based paints according to the present invention preferably has a surface tension adjusted to 20.0 mN / m or more and 60.0 mN / m or less, and is adjusted to 22.0 mN / m or more and 58.0 mN / m or less. It is more preferable. If the surface tension is more than 60.0 mN / m, the cleaning property is lowered, which is not preferable.

  In addition, the cleaning liquid for water-based paint according to the present invention may contain other organic solvents and the like within a range that does not impair the cleaning power and does not adversely affect the equipment and paint used.

  In addition, the pH of the cleaning liquid for water-based paints according to the present invention varies depending on the composition of the mixture, but is preferably adjusted within the range of 10-12. On the other hand, paints that can use the cleaning liquid of the present invention are water-based paints. Such water-based paints include those in which water is the main solvent or dispersion medium and an organic solvent or the like is mixed therein.

  Hereinafter, the cleaning liquid for water-based paint according to the present invention will be described in detail by way of examples. However, the present invention is not limited to the embodiments of the examples, and may be appropriately changed without departing from the gist of the present invention. can do. In addition, the evaluation method of the characteristic in each Example and each comparative example is as follows.

[Cleaning characteristics]
As shown in FIG. 1, a test panel 2 made of aluminum having a length of 100 mm, a width of 50 mm, and a thickness of 0.5 mm is prepared. No. 5 thermosetting water-based paint, trade name “WBC-713T”, color code 3R3) 4 was applied (the water-based paint was still wet after 5 minutes from application to the test panel 2). ). Thereafter, the test panel 2 coated with the water-based paint is dried at room temperature for a predetermined time (15 minutes), and then the lower half of the test panel 2 (the part where the water-based paint 4 is applied) is placed in the example or comparative example. It was gently immersed in the cleaning solution 6 and left for 30 seconds. After performing the cleaning for 30 seconds in this manner, the test panel 2 is gently pulled up from the cleaning liquid 6 and the surface condition after the cleaning is visually observed. Sensory evaluation was performed.
◎ ・ Approximately more than 80% of the test panel substrate is exposed ○ ・ Approximately 60% or more of the test panel substrate is exposed △ ・ Approximately 30% or more of the test panel substrate is exposed × ・・ The exposed part of the base of the test panel is less than 30%

[surface tension]
Using an automatic contact angle meter (DM-501) manufactured by Kyowa Interface Science Co., Ltd., based on the ds / de method, the maximum diameter of the hanging drop (equatorial plane diameter) de and the hanging drop under an atmosphere of 25 ° C. The suspended drop diameter ds at a position elevated by de from the lowest end was measured, and the surface tension was calculated using the following equation (1).
γ = Δρgd _e ² (1 / H) (1)
In the above equation (1), Δρ is a density difference, g is a gravitational acceleration, and 1 / H is a correction coefficient obtained from ds / de.

[Stability of cleaning solution]
By visually observing the state after the adjusted cleaning solution was left for 1 hour, the stability of each cleaning solution was sensory evaluated in the following three stages.
○ ・ ・ There is no phase separation and a uniform state is maintained.
△ ・ ・ Partial phase separation is observed.
× ·· Phase separation is observed as a whole.

<Example 1>
Polyether-modified organopolysiloxane (KF-6011, molecular weight 1,500, manufactured by Shin-Etsu Silicone Co.), which is a polyether-modified siloxane represented by the following chemical formula (Chemical Formula 3), with respect to 100 parts by weight of water, and 0.02 part by weight By mixing 1.0 part by weight of diisopropanolamine, the aqueous paint cleaning liquid of Example 1 was prepared (in the following chemical formula (Chemical Formula 3), x = 8 to 15). And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Examples 2 to 15>
Except that the mixing ratio of polyether-modified siloxane (polyether-modified organopolysiloxane) and diisopropanolamine was changed as shown in Table 1, the washing liquids for aqueous paints of Examples 2 to 15 were prepared in the same manner as in Example 1. . And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 16>
In 100 parts by weight of water, 0.02 part by weight of polyether-modified siloxane, 1.0 part by weight of diisopropanolamine, and an ethylene oxide (10 mol) adduct of acetylenic diol as a surfactant (manufactured by Nissin Chemical Industry Co., Ltd.) Olfin E1010) The aqueous paint cleaning liquid of Example 16 was prepared by mixing 0.1 part by weight. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 17>
The aqueous paint cleaning liquid of Example 17 was prepared in the same manner as in Example 14 except that the mixing ratio of the ethylene oxide adduct of acetylene glycol was changed to 1.0 part by weight. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 18>
The aqueous paint cleaning liquid of Example 18 was changed in the same manner as in Example 2 except that the type of polyether-modified organopolysiloxane was changed to KF-354L (molecular weight: 1,000 to 2,000) manufactured by Shin-Etsu Silicone. It was adjusted. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Examples 19 and 20>
The aqueous paint cleaning liquids of Examples 19 and 20 were prepared in the same manner as in Example 18 except that the mixing ratio of the polyether-modified siloxane (polyether-modified organopolysiloxane) was changed as shown in Table 1. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 21>
The aqueous paint cleaning solution of Example 21 was prepared in the same manner as Example 2 except that the polyether-modified siloxane was changed to the one represented by the following chemical formula (Formula 4). And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Examples 22 and 23>
The aqueous paint cleaning liquids of Examples 22 and 23 were prepared in the same manner as in Example 21 except that the mixing ratio of the polyether-modified siloxane (polyether-modified organopolysiloxane) was changed as shown in Table 1. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 24>
The aqueous paint cleaning liquid of Example 25 was prepared in the same manner as in Example 1 except that diethanolamine was used instead of diisopropanolamine as the alkanolamine. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Example 25>
The aqueous paint cleaning liquid of Example 25 was prepared in the same manner as in Example 1 except that monoisopropanolamine was used instead of diisopropanolamine as the alkanolamine. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

<Comparative Examples 1-6>
The aqueous paint cleaning liquids of Comparative Examples 1 to 6 were prepared in the same manner as in Example 1 except that the mixing ratio of the polyether-modified siloxane and diisopropanolamine was changed as shown in Table 1. And the above-mentioned washing | cleaning characteristic and surface tension were evaluated using the obtained washing | cleaning liquid for water-based paints. The evaluation results are shown in Table 1 together with the composition of the water-based paint cleaning solution.

  From Table 1, it can be seen that the cleaning solutions for water-based paints of Examples 1 to 25 all have good cleaning properties (the mixing ratio of the polyether-modified siloxane was 0.02 to 0.3 parts by weight). When the mixing ratio of alkanolamine is 0.5 to 1.0 parts by weight, or when a surfactant is mixed, it can be seen that the cleaning properties are much better). On the other hand, the water-based paint cleaning liquids of Comparative Examples 1 to 6 whose polyether-modified siloxane and alkanolamine contents do not satisfy the requirements of the present invention have poor cleaning characteristics and poor stability. I understand that

  Since the cleaning liquid for water-based paints of the present invention exhibits the above-described excellent cleaning ability for water-based paints, it can be suitably used as a cleaning liquid for water-based paints.

2. Test panel 4. Water-based paint 6. Cleaning fluid (water-based paint cleaning fluid)

Claims (2)

An aqueous paint cleaning liquid for cleaning an aqueous paint,
A cleaning liquid for water-based paints, comprising 0.01 to 7.00 parts by weight of polyether-modified siloxane and 0.5 to 10.0 parts by weight of alkanolamine based on 100 parts by weight of water.   The cleaning liquid for water-based paint according to claim 1, comprising a surfactant.

Images