Multiple color pattern poriuretanhuo - mu

摘要

PURPOSE:To obtain polyurethane foam with a colorful multicolor pattern by a method wherein pattern is formed by mixing foams with a plurality of color tones in polyurethane foam, which is obtained by the reaction of hydroxyl compound with isocyanate. CONSTITUTION:Colorant is intermittently charged in an introducing pipe line 6 to lead hydroxyl compound to a mixing head. A colorant tank 4, a pump 5 and a hydroxyl compound introducing pipe line 6 are connected by pipe lines 7 and 8 and a bypass pipe line 9 is connected between the pipe lines 7 and 8. An on-off valve 10 is provided near the introducing pipe line 6 in the pipe line 8. An on-off valve 11 and a throttle valve 12 are provided in the bypass pipe line 9. The colorant is charged in the introducing pipe line 6 with flows of hydroxyl compound by continuously running the pump 5 and opening the valve 10. The colorant is circulated through the bypass pipe line 9 by closing the valve 10 and opening the valve 11. The throttle valve 12 is used for maintaining the pressure of the colorant during circulation higher than its pressure during delivery in order to realize the stable charging of the colorant.