Zipper storage bags were patented by Robert W. Vergobbi on May 18, 1959. In the same year, Minigrip licensed them as pencil bags. Not until 1968 did Dow Chemical Company

Dow Chemical Company

The Dow Chemical Company is a multinational corporation headquartered in Midland, Michigan, United States. As of 2007, it is the second largest chemical manufacturer in the world by revenue and as of February 2009, the third-largest chemical company in the world by market capitalization .Dow...

 (already known for Styrofoam

Styrofoam

Styrofoam is a trademark of The Dow Chemical Company for closed-cell currently made for thermal insulation and craft applications. In 1941, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene...

 and Saran Wrap) begin marketing for them. The bags are known more commonly under the genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

 Ziploc

Ziploc

Ziploc is a brand of reusable, re-sealable zipper storage bags and containers originally developed by Dow Chemical Company, and now produced by S. C. Johnson & Son. According to Dow's website, the bags were originally test marketed in 1968....

 but Hefty

Hefty

Hefty is a brand name of trash bags, trash cans, foam disposable tableware, children’s disposable tableware, slider closure food storage and freezer bags, and disposable cookware. Hefty is a registered trademark of Pactiv Corporation...

and other companies manufacturer slider storage bags as well.