The International Trade Commission yesterday found that U.S. textile companies suffered economic injury from Chinese dumping of polyester-cotton cloth, triggering the imposition of duties that could drive the Chinese from the market.

The duties on the low-priced cloth could amount to as much as 10 cents for a linear yard on a product for which a half-cent difference in price can mean a tremendous competitive advantage, trade sources said.

This was the first time the Chinese have been found to be dumping goods on the American market, but there was no reaction from Peking yesterday on the ITC decision. In the past the Chinese have reacted forcefully to U.S. trade curbs, including a boycott of farm purchases in retaliation for a cutback last December in textile import quotas.

The ITC action came just three days after that dispute was settled with the signing of a new five-year agreement on textile imports that allows the Chinese a greater increase in their share of the U.S. market than the Reagan administration originally offered and that the other major textile exporting nations--Hong Kong, Taiwan and South Korea--received.

The American Textile Manufacturers Institute, which bitterly assailed the signing of the U.S.-Chinese agreement on Friday, yesterday applauded the favorable ITC decision in the complaint it filed last August on polyester/cotton printcloth imports.

The ITC acted after the Department of Commerce determined last month that the Chinese had been dumping polyester/cotton printcloth--a low-priced unfinished cloth ready for dyeing. Made by eight South Carolina companies, the medium-weight fabric is used mainly in apparel and furnishing.

The Commerce Department, comparing the prices China charged in the United States to the prices Thailand charged the European Economic Community, determined the Chinese cloth was being sold here at 22.4 percent below fair market value. That will be the amount of duty assessed on all Chinese shipments after last March 3, when Commerce made its preliminary determination of dumping.

China's share of the U.S. polyester/cotton printcloth market jumped from 0.05 percent in 1979 to almost 14 percent last year, when it supplied 61.5 percent of all such imports, the ITC said. U.S. companies saw their profits drop from $16.6 million in 1981 to $223,000 last year.