1.This standard specifies a method for measuring the bonding strength of common plywood as defined in GB9846.2.
2.Refer to the standard GB 9846.2 Plywood terms and definitions GB 9846.8 Plywood measurement of bonding strength extraction method GB 9846.9 plywood specimen saws GB 9846.10 Plywood specimen size measurement
Measuring tools and instruments
3.1 Vernier caliper, the reading accuracy of indexing is 0.01g.
3.2 Constant temperature water bath, 30 ~ 100℃.
3.3 Tensile testing machine, load reading accuracy of 5N.
3.4 Air convection drying oven, the temperature of each point in the oven can be maintained at 63±3℃.
4. sampling and specimen
4.1 Sample is extracted according to GB 9846.8.
4.2 Saw and cut the specimen according to GB 9846.9.
4.3 There shall be no material defects and processing defects that affect the bonding strength in the shear section of the specimen.
5.1 Measure the size of the specimen according to GB9846.10.
5.2 The specimens were treated under the following conditions according to the type of plywood they belong to:
A. Class I plywood: the specimen was boiled in boiling water for 4h, then dried in an air convection drying chamber at 63±3℃ for 20h, and then boiled in boiling water for 4h. After being removed, it was cooled at room temperature for 10min. When cooking the test piece, all the test parts should be immersed in boiling water and covered with boiling water. Note: the rapid inspection method of boiling for 3h is allowed in the production of the factory, and the measured result multiplied by coefficient 0.9 is used as the bonding strength value of the product inspection. However, in case of the dispute between the supply and demand for the reinspection of class ⅰ plywood, the 28h boiling and baking cycle method is still used as the cutting promotion method.