A one-piece container closure with a collar, stiff planar triangular leaflets attached by linear hinges to the collar, and thin flexible foldable webs attached to and extending between the leaflets. The leaflets are flat with the webs folded beneath in closed closure position. The leaflets are pivoted upwardly with webs unfolded therebetween in open position. An integral cap is attached to the collar by a snap-action bow-tie hinge. A central pin on the cap seals with the leaflets when the cap is closed. The closure is integrally molded in open position with raised leaflets and unfolded webs, leaflets then being lowered and the webs folded to closed position while the closure is still warm, the cap then being closed, and the closed closure then being annealed to establish the elastic positional memory of the leaflets and hinges in the closed position when product is not being dispensed through the closure.