GB/T17657-2013 Test Method for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels: Determination of Moisture Resistance – Boiling Water Boiling Test
- Determination of moisture resistance – boiling water boiling test
13.1 Principle
Determine the internal bonding strength of the specimen after boiling in water.
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13.2 Instruments and equipment
13.2.1 Universal mechanical testing machine (see 11.2.1).
13.2.2 Vernier caliper, with a division value of 0,1mm and a range of 0mm~150mm.
13.2.3 Water tank, which can be heated and can keep the water boiling,
13.2.4 Card head, which can be metal, hardwood or hardwood plywood, is matched with the fixture and the test piece is bonded to the card head. The density of hardwood or hardwood plywood is greater than 600kg/m3. If inspecting thin plates (thickness<8.0mm) or high-density boards (>800kg/m3), it is recommended to use metal clamps.
13.2.5 Blast drying oven, capable of maintaining a temperature of (70 ± 2) ℃.
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13.3 Test pieces
13.3.1 Specimen size
Length l=(50 ± 1) mm, width b=(50 ± 1) mm.
13.3.2 Sample balance treatment
If necessary, place the test piece and hardwood or hardwood plywood clamp in an environment with a temperature of (20 ± 2) ° C and a relative humidity of (65 ± 5)% until the mass remains constant. The difference between the two weighing results after a 24-hour interval does not exceed 0.1% of the mass of the test piece, which is considered to be a constant mass.
13.4 Method
13.4.1 Measure the width and length of the specimen at the centerline of its length and width (see 1).
13.4.2 Place the test piece in a water tank with a pH value of 7 ± 1 and a temperature of (20 ± 5) ° C, with the upper end of the test piece (75 ± 25) mm away from the water surface. The distance between the test pieces, as well as between the test pieces and the bottom and wall of the water tank, should be at least 15mm, so that water can flow freely. Slowly and uniformly heat the water to the boiling point (about 100 ° C) within (90 ± 10) minutes, and immediately start timing. The test piece continues to be boiled in boiling water for (120 ± 5) minutes, while the water remains slightly boiling to prevent rolling bubbles and strong water flow from eroding the test piece. The water should be replaced for each test.
13.4.3 After boiling with water, remove the test piece and immediately place it in a water bath at (20 ± 5) ° C to cool for (60 ± 5) minutes. The surface of the test piece is perpendicular to the water surface, and the distance between the test pieces, as well as between the test pieces and the bottom and wall of the water tank, should be at least 15mm.
13.4.4 Take out the test piece and dry it, and place it flat in a drying oven at (70 ± 2) ° C for (960 ± 15) minutes.
13.4.5 Remove the specimen from the drying oven, cool to room temperature, and then bond the specimen to the clamp head.
13.4.6 Determine the failure load according to 11.4.3 and 11.1.4.
13.5 Expression of Results
13.5.1 Calculate the internal bonding strength according to 11.5.1. The size of the test piece is calculated before boiling.
13.5.2 – The internal bonding strength of a board after boiling is the arithmetic mean value of the internal bonding strength of all test pieces in the same board after boiling, accurate to 0.01MPa.
