Flame retardant test: Tracking
Test standard

GB/T 4207; IEC 60112; EN IEC 60112

Definition

Comparative tracking index CTI: The maximum voltage value when five specimens are subjected to 50 drops of liquid without tracking failure and continuous combustion, expressed in volts (V), and also includes a description of material properties during the 100 drops test;

Proof tracking index PTI: The maximum voltage value corresponding to the five specimens being subjected to 50 drops of liquid without tracking failure and continuous combustion, expressed in volts (V)

Specimen

It is recommended to use specimens with a plane size of not less than 20mmX20mm and a thickness of not less than 3mm (can be stacked)

Sample environmental pretreatment

Unless otherwise specified, the specimen should be kept at (23±2)℃ and relative humidity (50±10)% for at least 24h.

The test should be started within 30 minutes after the sample is taken out of the conditioning chamber

When a sinusoidal voltage is applied to the electrode

Voltage range: 100V~600V; frequency range: 48Hz~62Hz; the maximum error of the voltage measuring device should not exceed 1.5%, and the power supply should not be less than 0.6kVA

Instrument self-calibration

When the effective value of the current is (0.50±0.05)A for (2.0±0.2)s, the overcurrent device should operate

Test solution

Solution A: Dissolve an analytically pure anhydrous ammonium chloride reagent with a mass fraction of about 0.1% and a purity of not less than 99.8% in deionized water to prepare a solution A with a resistivity of (3.95±0.05) Ω·m at (23±1)℃;

Solution B: Dissolve analytically pure anhydrous ammonium chloride (NH.CI) reagent with a mass fraction of about 0.1% and a purity of not less than 99.8% and sodium dibutylnaphthalene sulfonate with a mass fraction of (0.500±0.002)% in deionized water to prepare solution B with a resistivity of (1.98±0.05) Ω·m at (23±1)℃. (Some components of solution B are prohibited, so it is difficult to produce);

Solution C: Dissolve analytically pure anhydrous ammonium chloride (NHCI) reagent with a mass fraction of about 0.2% and a purity of not less than 99.8% and a non-ionic surfactant (octoxynol) with a mass fraction of (0.50±0.02)% in deionized water to prepare solution C with a resistivity of (1.98±0.05)Ω*m at (23±1)℃. The surface tension of solution C is less than 40mN/m.

Electrode

Platinum metal with a purity of at least 99%, the rectangular cross-section of the two electrodes should be (5.0±0.1) mmX(2.0±0.1) mm, and the angle of the end bevel should be (30±2)°

The blade of the bevel should be approximately flat, about 0.01 mm~0.10 mm wide

Operational procedures

Maintain the temperature at (23±2)℃, the relative humidity at (50±10)%; the test solution is 35±5 mm above the sample;

The solution drips at the center of the electrode at a time interval of 30±5S; the mass of 50 consecutive drops should be 0.997g~1.147g, and the mass of 20 consecutive drops should be 0.380g~0.480g;

The time for dripping 50 drops on the sample should be 24.5min±2min.

Result determination

The test shall be stopped if the following situations occur:

a) the overcurrent device is activated;

b) continuous combustion occurs;

c) at least 25 seconds have passed since the 50th (100th) drop of liquid was dripped, and no situation a) or b) occurs.