Resistance to cold and hot temperature difference refers to the ability of paint film to resist damage in the process of temperature change from low to high or from high to low. According to the national standard GB4893.7-85, paint film is resistant to cold and hot temperature difference performance measurement method is as follows:

1. المعدات والمواد: constant temperature and humidity box (temperature higher than 60℃, الرطوبة النسبية 98% ~ 99%), low temperature refrigerator (temperature lower than -40℃), توازن, electric stove, عدسة مكبرة, bristling brush, paraffin and rosene, إلخ.

The determination method of resistance to cold and hot temperature difference is illustrated in Figure 1

طريقة تحديد المقاومة للاختلافات في درجات الحرارة الساخنة والباردة

2. خطوات الاختبار:

Four samples were taken, one of which was used as a comparison model and the remaining three as tests. A mixture of paraffin and rosin (1:1 نسبة) was used to seal the periphery and back of the specimen.

Put the closed sample into a constant temperature and humidity box (temperature 40±2℃, رطوبة 98% ~ 99%) and keep it for 1 ساعة.

The samples were removed and immediately placed in a low temperature refrigerator (temperature -20±2℃) ل 1 ساعة.

The above temperature change steps were repeated, and after every three cycles, the samples were placed in an environment of 20±2 ° C and 60% ~ 70% relative humidity for 18 ساعات.

Observe sample, يستخدم 4 times the magnifying glass to observe any crack, فقاعة, obvious loss of light and color, وهلم جرا وهكذا دواليك.

طريقة تحديد المقاومة للاختلافات في درجات الحرارة الساخنة والباردة

According to the agreement between the supply and demand parties, different cycles can be selected, مثل 3, 6, 9, 12, 15, 18 weeks, إلخ.

If cracks, محتدما, significant loss of light, تغير اللون, إلخ. occur during the inspection process, the sample is judged to be unqualified.

The test of temperature difference between cold and hot can simulate the performance of the paint film under temperature change, help to evaluate the stability and durability of the paint film, and ensure that the paint film will not be damaged or quality problems under different temperature conditions.