Dalian Mingcheng packaging Limited properties of gypsum based board requirements aspects: 1) tensile strength and wet strength to high. The tensile strength and wet strength is a key indicator of the cover board. The strength of the gypsum board mainly rely on the cover board tensile Dulai guarantee. In the gypsum board production line, upper and lower board has a touch of gypsum slurry, so have the wet strength enough, otherwise it will be broken in the gypsum board production line, the line outage. Board also have certain properties, in wet and drying process does not occur, bulging, wrinkling and deformation. 2) water absorption and water resistance to the appropriate. Facing board requirements on water absorption and water resistance is strict, because it and the gypsum core material must be tight, firm adhesion. Bonding mechanism is: when the board and gypsum slurry contact, from the gypsum slurry to absorb a portion of water, with water permeation and diffusion, ultrafine gypsum and gypsum solution supersaturated partial penetration to needle like crystals formed fibrous tissue paper (solidification), the crystallization of Criss Cross, the board and gypsum closely bonded together. This requires the board to have certain water absorption, but its absorbing speed and quantity (i.e., permeation rate and permeation of the gypsum liquid) to maintain the right amount, to the initial setting time and gypsum anastomosis, can guarantee the quality of gypsum board. At the same time, water quantity must have certain limit, the water can not penetrate into the surface of the paper, otherwise it will affect the strength of paper, so the requirement of surface layer, the core layer based board should have a certain degree of water resistance.