板材含水率对人造板表面胶合强度影响数据

影响强度：人造板材表面胶合强度与单板的含水率密切相关。过高或者过低的含水率都会影响到表面胶合强度。当单板的含水率过高时,人造板材易发生开裂和翘曲现象,从而导致人造板材的强度降低。而当单板的含水率过低时,胶合板的板面易出现干缩、开裂等情况,表面胶合强度也受到影响。因此,控制单板含水率是确保表面胶合强度的关键。
影响稳定性：合理控制单板含水率可以保证人造板材的稳定性。当单板的含水率过高时,人造板材吸收水分后容易发生鼓包等变形现象,从而影响人造板材的稳定性。而当单板的含水率过低时, 人造板材在使用过程中容易发生变形、开裂等现象,同样影响到了人造板材的稳定性。因此,控制单板含水率是提高人造板材稳定性的重要措施。合理控制单板含水率可以提高人造板材的质量。具体地,可以从以下几个方面入手: 1、控制木材的含水率 木材在制作人造板材之前需要进行烘干处理,以降低其含水率。在具体操作中,应该控制好烘干温度和烘干时间,确保木材含水率稳定在合理的范围内。含水率
测定含水率时，试件在锯割后应立即进行称量，精确至0.01g。如果不能立即称量，应避免试件含水率在锯割至称量期间发生变化。试件在温度（103±2）℃条件下干燥至质量恒定，干燥后的试件应立即置于干燥器内冷却，防止从空气中吸收水分。冷却至室温后称量，精确至0.01g。前后相隔6h两次称量所得的试件质量差小于试件质量的0.1%，即视为试件质量恒定。试件的含水率H=(m0-m1)/m1×100%。试件取算术平均值记为最终结果。
表面胶合强度
采用热熔胶将试件与专用卡头胶合在一起，试机均匀加载荷直至试件被破坏，记录最大载荷值。试件表面胶合强按σ=F_max/A （F_max-最大载荷值；A-试件与卡头粘合面积）

Impact on Strength: The surface bonding strength of wood-based panels is closely related to the moisture content (MC) of veneers. Both excessively high and excessively low MC will impair the surface bonding strength. When the MC of veneers is too high, wood-based panels are prone to cracking and warping, which reduces the strength of the panels. When the MC of veneers is too low, the surface of plywood is prone to shrinkage, cracking and other issues, and the surface bonding strength is also affected. Therefore, controlling the MC of veneers is the key to ensuring surface bonding strength.

Impact on Stability: Properly controlling the MC of veneers can ensure the stability of wood-based panels. When the MC of veneers is too high, wood-based panels are prone to deformations such as bulging after absorbing moisture, which affects the stability of the panels. When the MC of veneers is too low, wood-based panels are prone to deformation, cracking and other phenomena during use, which also affects the stability of the panels. Therefore, controlling the MC of veneers is an important measure to improve the stability of wood-based panels. Properly controlling the MC of veneers can improve the quality of wood-based panels. Specifically, it can be carried out from the following aspects:
1. Control the moisture content of wood
Before manufacturing wood-based panels, wood needs to be dried to reduce its MC. In specific operations, the drying temperature and drying time should be properly controlled to ensure that the wood MC is stabilized within a reasonable range.

Moisture Content Determination
The test specimen shall be weighed immediately after sawing, accurate to 0.01 g. If weighing cannot be carried out immediately, the change of the specimen's MC during the period from sawing to weighing shall be avoided. The specimen shall be dried to constant mass at (103±2)℃, and the dried specimen shall be immediately placed in a desiccator for cooling to prevent moisture absorption from the air. Weigh after cooling to room temperature, accurate to 0.01 g. The mass difference of the specimen obtained from two weighings separated by 6 hours is less than 0.1% of the specimen's mass, which is regarded as the specimen reaching constant mass. The moisture content H of the specimen is calculated as H=(m0-m1)/m1×100%. The arithmetic mean of all test specimens is taken as the final result.

Surface Bonding Strength
The specimen and the special chuck are bonded together with hot melt adhesive. The testing machine applies a uniform load until the specimen breaks, and the maximum load value is recorded. The surface bonding strength of the specimen is calculated as σ=F_max/A (F_max: maximum load value; A: bonding area between the specimen and the chuck)