GB/T 9780-2013Test method for dirt pickup resistance and stain remvoal of film of architectural coatings and paint (English PDF)

4.1 Standard test conditions

The standard test conditions are temperature (23 ± 2) °C AND relative humidity (50 ± 5) %.

5.1 Test equipment and materials

5.1.2 Reflectance meter. in accordance with the requirements of 4.1 in GB/T 23981-2009.

5.1.3 Electronic balance. sensitivity of not more than 0.1 g.

5.1.4 Electric blast oven. accuracy ± 2 °C.

5.1.5 Wire rod coater. specifications of 80 µm and 120 µm.

5.1.6 Basic gray scale. complies with GB/T 250.

5.2 Test contamination sources

5.2.1 Contamination source

USE the national standard sample of Ash reference sample for dirt pickup resistance test of building coating.

5.3 Preparation and curing of sample plate

5.3.1 TREAT the surface of the substrate complying with the requirements of 5.1.9 in accordance with the requirements of 10.2 in GB/T 9271-2008.

5.4 Brushing method

5.4.1 Test procedure

5.4.1.3 Method B (drying oven fast method)

5.4.1.3.1 PLATE the sample plate of 5.4.1.1 in the (60 ± 2) °C drying oven for 30 min; TAKE it out and PLACE it under the standard test conditions for 2 h;

MOVE it onto the sample plate rack of the rinse device; OPEN the rinse device valve to its uttermost position which had been filled with 15 L of water, to rinse the coating sample plate.

5.4.2 Results calculation

The exterior wall coating and paint dirt pickup resistance is calculated in accordance with the equation (1).

5.5 Dipping method

5.5.1 Test procedures

6.1 Test equipment and materials

6.1.3 Electronic balance. sensitivity of 0.1 g.

6.1.4 Wet film preparation device. the 150 µm gap type wet film preparation device made of stainless steel, with the prepared coating width of 100 mm.

6.1.5 Scraper. it may be any suitable shape and size AND the blade is made of appropriate materials, such as stainless steel or plastic.

6.1.6 Test gauze. the cotton wool gauze in accordance with YY 0331.

6.2 Cleaning medium and stain for test purposes

6.2.1 Cleaning medium for test purposes

DISSOLVE the phosphate-free detergent complying with the requirements of GB/T 13171.2 into the level III water complying with GB/T 6682, to prepare the detergent powder solution of the mass fraction 2%, the pH value of which is 9.5 ~ 11.0.

6.2.2 Stain for test purposes

6.2.2.4 Water-soluble melanin solution

In accordance with the specified proportion, ADD water into the vessel; AND the water quality shall comply with the level III water requirements as specified in GB/T 6682. Under the mixing conditions, slowly ADD water-soluble melanin (CAS 8005-03-6), were the mass ratio between water and water-soluble melanin is 97.3; fully STIR it until the melanin is completely dissolved. During each test, it shall be prepared 24 h in advance, AND the shelf life of the prepared solution is 168 h.

6.2.2.6 Vaseline carbon black mixture

The medium color carbon black (CAS 1333-86-4) complying with GB/T 7044, the parameters of which are as follows. oil absorption (95 ± 5) mL/100 g, particle size (20 ± 2) nm, specific surface area (180 ± 20) m²/g, and tinting force >= 128%.

6.3 Preparation and curing of sample plate

The sample shall be uniformly coated on a substrate specified in 6.1.7 with a wet film preparation device complying with the requirements of 6.1.4. At least one sample plate shall be prepared for each stain.

Unless otherwise specified, the sample plates shall be cured under standard test conditions for 168 hours.

6.4 Test procedures