METHOD FOR PURGING PAINT CIRCUITS AND WATERBORNE PURGE CLEANER

Abstract

Described herein is a waterborne purge cleaner solution with improved cleaning efficiency and reduced VOC (Volatile Organic Compound) content as well as a concentrate for producing the purge cleaner solution.

Claims

1. A waterborne purge cleaner solution comprising at least one glycolether, which comprises hexylglycol and/or hexyldiglycol, characterized in that it additionally comprises at least one water-soluble amine having 7 to 15 carbon atoms, which is selected from the group consisting of N-methyldiisopropanolamine, N-octyldiethanolamine, triisopropanolamine and N,N-dibutylethanolamine, wherein the solution contains only hexylglycol and/or hexyldiglycol as the at least one glycolether.

2. A concentrate for producing the waterborne purge cleaner solution according to claim 1 characterized in that the purge cleaner solution is obtainable by diluting the concentrate with water, and adjusting the pH value, if required, with at least one acid or base.

3. The concentrate according to claim 2 characterized in that it comprises a) 1 to 40% (w/w) of at least one amine having 7 to 15 carbon atoms, b) 40 to 60% (w/w) of hexylglycol, and c) 40 to 60% (w/w) of hexyldiglycol.

4. The concentrate for producing the waterborne purge cleaner solution according to claim 1 characterized in that the purge cleaner solution is obtainable by diluting a concentrate with water by 5:1,000 to 30:1,000 and adjusting the pH value, if required, with at least one acid or base.

Description

EXAMPLES

Test 1: Quantitative 9 Drops Test on Wet Paint5 Min. at RT

[0057] A waterborne paint layer with a thickness between 40 to 60 m was extended on a glass panel (200200 mm). The layer was then partially dried for 4 minutes at room temperature (RT) and placed at a slope of 45. At a rate of 1 drop per second and from a height of 12 cm, 9 drops of the purge cleaner solution to be tested were added onto the panel.

[0058] After 5 minutes at room temperature, the width of the paint-free spot where the drops had hit the panel (open head), in cm was measured. The larger the width, the better the stripping effect, i.e. the cleaning efficiency, of the tested solution.

Test 2: Spray on Wet Paint Test10 Min. at RT

[0059] A waterborne paint layer with a thickness of approx. 60 m was extended on a glass panel (100200 mm). The layer was then partially dried for 4 minutes at room temperature and placed at a slope of 45. From 30 cm distance, 10 ml of the purge cleaner solution to be tested were sprayed on the panel.

[0060] After 10 minutes at room temperature, the stripping effect, i.e. the cleaning efficiency, was evaluated according to the following categories: Bad (), regular (+), good (++) and very good (+++).

Test 3: Quantitative N Drops Test on Dried Paint

[0061] A waterborne paint layer with a thickness between 40 to 60 m was extended on a glass panel (200200 mm). The layer was then dried for 24 h at room temperature and placed at a slope of 45. At a rate of 1 drop per second and from a height of 12 cm, drops of the purge cleaner solution to be tested were added onto the panel until the layer was opened, i.e. until there was a paint-free spot where the drops had hit the panel.

[0062] The number of drops (n) added was determined. The lower the number, the better the stripping effect, i.e. the cleaning efficiency, of the tested solution.

Purge Cleaner Solutions and Test Results

[0063] For every amine A, B and C (see below), a mixture of 95 wt.-% of hexyldiglycol and 5 wt.-% of amine was prepared. [0064] Amine A: Triethanolamine (6 carbon atoms) (comparative example) [0065] Amine B: N-methyldiisopropanolamine) (7 carbon atoms) (inventive example) [0066] Amine C: N,N-dibutylethanolamine (10 carbon atoms) (inventive example)

[0067] The mixtures were diluted with deionized water to 2 wt.-%.

[0068] The Quantitative 9 Drops Test was performed as described above (Test 1) on the wet paint Fller Red (Hemmelrath, Germany).

[0069] The results are summarized in the following table wherein the cleaning efficiency was calculated compared to the one with triethanolamine (amine A) which was considered as reference.

TABLE-US-00001 Amine Width of open head in cm Cleaning efficiency in % A 1.45 100 B 1.51 104 C 1.48 102

[0070] The Spray Test was conducted as described above (Test 2) on the wet paint Fller Red (Hemmelrath, Germany) as well and showed the following results:

TABLE-US-00002 Amine Cleaning efficiency A + B + to ++ C ++

[0071] For amines A and B, the Quantitative N Drops Test was performed as described above (Test 3) on the dried paint Fller Red (Hemmelrath, Germany). The results are summarized in the following table. The cleaning efficiency was calculated compared to the one with triethanolamine (amine A) as a reference.

TABLE-US-00003 Amine Number of drops (n) Cleaning efficiency in % A 20 100 B 9 222

[0072] Surprisingly, all tests revealed an improved cleaning efficiency of the inventive purge cleaner solutions containing a water-soluble amine with at least 7 carbon atoms (amines B and C) compared to a purge cleaner solution which contains an amine having 6 carbon atoms (amine A).