Document ID: chunk:federal_register_of_legislation:F2015C00542:reg:1:p8
Version: federal_register_of_legislation:F2015C00542
Segment Type: reg
Provision Reference: reg 1 (pt 8/43)
Character Range: 167191–169738

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).

Figure 23

Arrangement of flexibility test

Figure 24

Tool with six blades

13.3. Test Method
 Cut through the coating on to the subsurface a pattern with 6 cuts and perpendicular to this, another one so that a grid with 25 squares arises (grid-cut).
 The cutting tool should be drawn steadily with a speed of 2 to 5 cm/s so that the cuts reach the subsurface but do not penetrate too deeply.
 The cutting is conducted in such a way that the two leading heads at the edge of the apparatus touch the surface uniformly. After the test the cuts are examined with a magnifying glass to check that they reach the subsurface. The test is carried out at least at two different positions of the sample. After the cuts have been produced they are brushed 5 times with slight pressure in both diagonal directions with a hand brush with polyamide bristles.
13.4. Interpretation of results
 The grid cuts are examined with a magnifying glass. If the cut edges are perfectly smooth and if no part of the coating is detached then it will be given a cross cut value of Gt0. If there are small fragments detached at the intersection of the cuts and if the exposed area amounts to about 5 per cent of the grid area the cut value is Gt1.
 Larger areas of detachment will be graded in the range Gt2 to Gt5.
Cut value grade  Exposed area of the grid area
Gt2              between 5 and 15  per cent
Gt3              between 15 and 35  per cent
Gt4              between 35 and 65  per cent
Gt5              higher than 65  per cent

Annex 4
  Toughened-glass windscreens
1.