GB/T 4893.7-2013Test of surface coatings of furniture - Part 7: Determination of surface resistance to alternation of heat and cold (English PDF)

2.1 temperature and humidity chamber

Accuracy ± 1 °C.

2.2

four times the magnifying glass.

2.3 edge materials

aluminum foil tape or flat brush temples, paraffin wax and rosin.

2.4

furnace.

2.5

dry cotton cloth.

3.1 Sample size 250mm × 200mm

After finishing the specimen shall not be less than 15 °C temperature environment placed ventilation after 7d experimenting. May also be in the rear has been completely dried finished furniture directly test specimen preparation.

3.2 Number of samples of four

3 a test, a comparison.

3.3

specimen surface smooth, no bubble, scratches, faded, wrinkled skin and other defects.

4.1 Pretreatment

Before the test specimen shall be at a temperature of 20 °C ± 2 °C, relative humidity of 60% to 70% for pre-processing 24h.

4.2 Test cycle

Should be based on the requirements of product standards or determine supply and demand side, the absence of special provisions, the recommended temperature is 40 °C ± 2 °C, relative humidity

95% ± 3% and -20 °C ± 2 °C; with 3 cycles.

4.3 Determination

4.3.1

Edge material with predetermined sides and back of the sample seal. The use of paraffin wax - rosin mixture Edge, the mixing ratio of 1.1.

4.3.2

specimens should be placed inside the constant temperature and humidity level.

4.3.3

a test cycle consists of two phases. The first stage. temperature 40 °C ± 2 °C, relative humidity of 95% ± 3%, 1h; the second stage

Section. Cold -20 °C ± 2 °C, 1h. High and low temperature transfer time shall not exceed 2min.

After the test at the end of 4.3.4, the sample at 20 °C ± 2 °C, relative humidity of 60% to 70% of the conditions placed 18h, dry with a clean cotton cloth

Cleaning the surface to be checked.