国产美女白丝袜精品_a不卡,美女一级毛片免费观看,国产精彩刺激对白视频,一级二级毛片,在线欧美色,国产一级毛片免,成年美女在线观看免费视频

Gum arabic has been used in printing industry for a long time.
Gum arabic is weak acid and water-soluvle, so it is used as one of the raw materials of Solution Fountain.Gum arabic can protect the roller and the layout of non seal part to prevent dirt production, and prolong the time of wetting layout.
Gum arabic solution usually can be used in printed sheet because of its good film forming property. It can protect the layout to use it in the future. The usage method of gum arabic solution is coating by hand or adding into plate machine.