Henan Xinxiang No.7 Chemical Co., Ltd is specialized in manufacturing oil field drilling fluid additives. We are the first and now the largest manufacturer of sulfonated asphalt here in China. We have always been focusing on the producing and researching of oilfield chemicals since the very beginning of our establishment, and are playing an important role in both domestic and international market. We began to research and develop the production of sulfonated asphalt in 1983 under the ...