Adds sales, segment details, background July 21 (Reuters) - Chemicals maker Dow Inc DOW.N reported a fall in second-quarter profit on Thursday, as surging inflation and COVID-19 lockdowns in China dented demand for its products. Dow's chemicals, used in a wide range of products including food packaging, mattresses, textiles and electronics, suffered a slowdown in orders from the key Chinese market as Beijing imposed widespread restrictions to contain COVID-19 flare-ups. Overall, Dow's net sales increased about 13% to $15.66 billion.