Method of applying chemicals to the sample

Reg43 Rev2 Ann3 fig 22

11.2.5. Indices of difficulty of the secondary characteristics

The other secondary characteristics are not concerned.
11.2.6. Interpretation of results
11.2.6.1. The test for resistance to chemical agents shall be considered to have given a satisfactory result if the sample does not exhibit any softening, tackiness, crazing or apparent loss of transparency.
11.2.6.2. A set of samples shall be considered satisfactory with regard to the test for resistance to chemical agents if one of the following conditions is met:
11.2.6.2.1. All the tests have given a satisfactory result;
11.2.6.2.2. One test having given an unsatisfactory result, a new series of tests carried out on a new set of samples has given a satisfactory result.
12. Flexibility test and fold test
12.1. Scope
With this test has to be found out whether a plastic is to be classed into the categories of rigid or flexible plastics.
12.2. Test method
From the material of the nominal thickness a rectangular flat sample 300 mm long and 25 mm wide is cut out and horizontally clamped into a clamping device in such a way that 275 mm of the length of the sample freely extend over the holding device. This free end shall be supported horizontally by an appropriate device until the test begins. Sixty seconds after removal of this support the vertical deviation of the free end is indicated in mm. If this deviation exceeds 50 mm a 180° fold test is performed subsequently. The sample is folded concisely, after that it is folded round 0.5 mm thick piece of sheet metal in such a way that it tightly contacts it on both sides.
12.3. Test conditions

Temperature: 20 °C ± 2 °C

Relative humidity: 60 ± 5 per cent

12.4. Requirements
The vertical deviation shall be more than 50 mm for flexible plastics, and 10 seconds after a 180° - folding the material shall not show any fracture-like damages at the point of buckling (see Figure 23).
13. Cross-cut test
13.1 Scope
This test gives a simple method to determine the adhesion of coatings to the subsurface. The brittleness and other strength characteristics can be evaluated.
13.2. Apparatus
Cutting tool with 6 blades set at 1 mm apart. A magnifying glass with an enlargement of 2 x to examine the crosscut specimen (see Figure 24).