1.4 Working environment for performance testing of plastic products
The working environment for performance testing of plastic products shall be: temperature (23 ± 2) ℃, relative humidity (45%~75%) and air pressure (86~106kPa) according to the provisions of GB 2918.
When testing the performance of plastic products, it is very important to require the environmental conditions to be fixed. Only this condition is guaranteed, can more accurate test results be obtained. This is determined by the special structure of plastic polymer. The instability of environmental conditions will lead to differences in mechanical properties, and accurate test results will not be obtained.

1.5 Detection test of resin melt flow rate
The melt flow rate of the resin refers to the mass of the melt material that can pass through the die with standard diameter every 10min under certain temperature and load conditions. The melt flow rate - 2 (MFR) is g/10min.
Melt flow rate is one of the main parameters in the quality of thermoplastic resin and the processing technology of its products. The higher the MFR value, the lower the molecular weight, the better the fluidity of the melt, but the worse the polymer strength.
(1) Equipment for melt flow rate detection test
① The structure of the melt flow rate indicator tester is shown in Figure 1-1. The equipment shall be equipped with heating and temperature control devices, and the temperature control accuracy shall be ± 0.5 ℃.
Fig. 1-1 Structure of Melt Flow Rate Meter
1 - Pressure load weight; 2 - Insulation sleeve; 3 - Temperature to 1mg.
Durometer; 4 - Material pressing rod; 5 - Thermal insulation layer; 6 - Furnace body; 7 - Material barrel; 8 - Temperature control element;
9 - Standard discharge die opening; 10 - Thermal insulation pad; 11 Tray
② Measuring and reusing balance, accuracy
③ Use a stopwatch for timing, accurate to 0.1s.
(2) Operation sequence of melt flow rate detection test
① The melt flow rate meter heats up.
According to the different plastic varieties of the test sample, refer to Table 1-4 and Table 1-5 to heat to the required temperature of the sample, and then keep the temperature constant for 15min.
② The MFR value of the sample is preliminarily estimated, and the sample material is measured and added into the barrel according to Table 1-6.
③ The sample material shall be preheated in the barrel for 4 min, the barrel shall be heated up to the test lagoon of the sample (Table 1-5), and the pressing rod shall be pressed by hand to drop to the point where the annular mark is 5~10 mm from the barrel mouth. Refer to Table 1-4 and Table 1-5, and add corresponding weights to the pressure bar.
④ When the pressing bar with the specified load is lowered to the level of the lower annular mark and the barrel mouth, cut off the strip that has flowed out.
⑤ Start cutting test strips according to the sample cutting interval specified in Table 1-6.
⑥ The sample strips are weighed on the balance after cooling, and the MFR value is calculated as follows.
(3) Precautions for melt flow rate detection test
① The cut sample strip shall be at the effective position of the pressing bar (i.e., at the ring mark).
② The strips used for testing shall be free of bubbles and impurities.
③ During the testing of easily oxidized and degradable materials, nitrogen shall be used to purge the cylinder before loading.
④ This test method for the melt flow rate of thermoplastics is arranged according to the national standard GB3682.

1.6 Common data
See Table 1-7~Table 1-10 for the commonly used physical quantities and codes of commonly used raw materials in plastic processing.