Joseph J. (Joe) Philips, 78, president of the Philips Police Equipment Co. in Washington, died Friday at his home in Silver Spring after apparently suffering a heart attack.

Although he was in semi-retirement, he continued to be active in the business he founded in about 1950. The firm sells flashlights, belts, cartridge holders and other items needed by law enforcement officials as well as special equipment for their cars.

Mr. Philips was born in New York City. He came here as a child with his family. During the early 1930s, he joined the Washington police department as a civilian and worked in the police equipment unit until 1947.

During this period, he aslo attended night classes at the old National University, where he earned a law degree. He practiced law here from 1947 until the mid-1950s.

Mr. Philips was a member of the Benjamin Franklin Blue Lodge No. 50 of the Masons, the Scottish Rite, Almas Temple and the Circle Club.

He is survived by his wife, Florence, of the home; a son, Leonard T., of Oxon Hill; two daughters, Sandra Pyle, of Columbia, Md., and Thelma Hawkins, of San Angelo, Tex.; a brother, Lazarus, of Philadelphia, 10 grandchildren and one great-grandchild.