John T. Dorrance Jr., 70, former chairman of Campbell Soup Co. and a leading patron of the Philadelphia Museum of Art, died in April 1989. Mr. Dorrance retired in 1984 after 22 years as chairman of Campbell but remained on the board of directors of the Camden-based processed-food giant. He was the son of John T. Dorrance Sr., whose invention of condensed soup helped bring the company - originally called the Joseph Campbell Preserve Co. - its phenomenal success. With a net worth estimated by Fortune magazine in 1987 at $1.5 billion, Mr. Dorrance was frequently listed among the world's wealthiest people. The only boy among four children, Mr. Dorrance was born in Cinnaminson on Feb. 7, 1919. His father, whom he called "the hero of my life," died when he was only 11. Dorrance graduated from St. George's School in Newport, R.I., and Princeton University. In addition to his work with Campbell, Dorrance also served on the board of directors of J.P. Morgan & Co. Inc., the Nieman-Marcus Group Inc. and the Penn Mutual Life Insurance Co. He also served on the boards of the Wistar Institute; the Princeton University trustees; the Church Farm School, Paoli; Hampton University, Hampton, Va.; the Eisenhower Exchange Fellowships; the Academy of Natural Sciences; the Philadelphia Maritime Museum; the PennJerDel Corp., and the World Wildlife Fund. He was a member of the Union League, the Philadelphia Club, the Corinthian Yacht Club, the Rittenhouse Club, the Gulph Mills Golf Club, the Merion Cricket Club and the New York Yacht Club. Mr. Dorrance is survived by his wife, Diana Rogers Dripps Dorrance; two sons, John III and Bennett, and a daughter, Mary Alice Dorrance Malone.