| 摘要 |
A paper is indicated which is especially suitable for use as cover sheets in the production of gypsum wallboards. The paper is sufficiently porous to allow better drainage and faster drying in the production of the paper, and when the paper is applied to the surfaces of a gypsum emulsion to form wallboards, the effect is that less heat is used in the transformation to wallboards. Savings are thereby made in the energy used to dry the board. The paper contains in percent by weight: A) Fibres in a quantity of 65-90% and having a CSF value (Canadian Standard Freeness) of 350-550 ml, B) a mineral filler in a quantity of 10-35%, C) a bonding agent in a quantity of 1-3.5%, D) a flocculating agent in a quantity of 1-2 kg/tonne E) a weighting agent in an effective quantity for preventing water penetration. In a preferred embodiment, the paper is treated with an internal weighting agent during its formation and it is then treated, after the formation, with a surface- weighting agent for achieving better adhesion to the gypsum core. |
