Roy J. Plunkett's discovery of Teflon in 1938 was just the start of a long process through which E. I. du Pont de Nemours & Co. brought the slippery substance out of the test tube and onto the frying pan.

Because the giant chemical corporation focuses on producing the raw materials that other companies use in manufacturing goods, it had to take different steps from the ones that, say, Eastman Kodak Co. took when it developed and marketed its Disc Camera.

Once Plunkett had discovered Teflon inside a supposedly empty metal cylinder and once its unique properties had been recognized, Du Pont's scientists and technicians had to puzzle over how to use it, Plunkett recalled last week. He was in Washington to be inducted into the National Inventors Hall of Fame.

Plunkett was asked how unusual it is for employes who have worked on a Du Pont innovation to leave the company to set up their own firms to manufacture and market products that use a raw material supplied by Du Pont. Plunkett said that situations of this kind occurred with fellow employes who worked on Teflon, but that he does not know whether it is more prevalent at Du Pont than at other companies that manufacture raw materials.

One example is Wilbert L. Gore, chairman of W. L. Gore and Associates of Newark, Del. Gore founded his company in 1958 after 12 years at Du Pont as a research supervisor. He and his company are best known for Gore-Tex, a waterproof, breathable, Teflon-based fabric used in running suits, space suits, camping gear, artificial arteries and other medical products. He was part of a task force at Du Pont that was working on finding different uses for Teflon.

According to Don Harkey, director of Du Pont's fluoropolymers division, a raw-materials producer can design a product to meet an identifiable need, or discover a product such as Teflon with very unusual properties and set about finding the appropriate market for it. The latter approach is less usual, he said.

Harkey said that Du Pont would deal with an innovation such as Teflon by forming a task force to look into possible commercial applications. The panel would have to decide which applications have enough value to generate a real market, how to produce the raw material and how the customer can make the end-use product.

The last question was important in the case of Teflon, because standard plastic-processing equipment couldn't handle the new material, so Du Pont developed new processing equipment, Harkey said.

Having an employe leave Du Pont to form a company that will manufacture goods from raw materials developed by Du Pont -- as Gore and others have done -- has its good and bad aspects, according to Harkey: "Anyone hates to see talented people leave the organization but we certainly benefit from someone going out to develop a market" for one of Du Pont's products.

Unlike Gore, Plunkett did not leave Du Pont to develop and sell products that use Teflon. Within a year after his discovery, he became a chemical supervisor for the manufacture of tetraethyl lead. He earned promotions in that division and in the company's Freon products section before being named director of Freon operations in 1970. He retired in 1975.

Asked what Du Pont does -- or what any company should do -- to encourage its researchers, Plunkett replied: "The only desire of a researcher is to be innovative." He said that people do their best when there is a reward -- such as money.

He also noted that among the advantages a company researcher has over the basement inventor is "you don't have the risk -- the company takes the fall" if the research or the innovation doesn't pan out.

Despite these advantages, Plunkett does not believe that the day of the basement invention is over: "Happens all the time," he asserted.

Also inducted last month into the National Inventors Hall of Fame:

* Marvin Camras, for the forerunner of the modern tape recorder, patented in 1944.

* Willis Haviland Carrier, for modern air conditioning, in which humidity is controlled along with temperature, patented in 1906.

* Dr. William J. Kolff, for the artificial heart, patented in 1972.

* And, finally, Louis Marius Moyroud and Rene Alphonse Higonnet, who were granted a patent in 1957 for an invention that produced this newspaper: the phototypesetting machine.