Method for improving filling property of rigid polyurethane foam plastics

The present invention relates to a method for improving filling property of hard polyurethane foamed plastic. The invention is characterized in that an air induction device is adopted for controlling the inner pressure of cavity of hard polyurethane foamed plastic in the foaming process. The gas which affects the flow of reaction solution is leaded out to cause that the reaction solution easily flows in the whole foaming reaction process. The invention can continuously lead out the gas which affects the generation of reaction solution so that the reaction solution easily flows in the whole reaction process. The problems of low flow property and inferior filling property in the prior forming process of polyurethane are essentially settled. The filling property in the foaming forming process is greatly improved. The filling amount of hard polyurethane foam prepared according to the invention is reduced by 5-20% at the state that the performance is guaranteed compared with the state that the invention is not adopted. The invention can be actualized with the existing foam production device which is little reformed.