Elastic Strand Bonding without the Use of End-Block Resins

It is common in the hygiene industry to make elastic laminates by bonding elastic strands using an adhesive. The laminate comprises a layer of non-woven, elastic strands, and a polypropylene back sheet. These three components are held together using an adhesive. Many kinds of adhesives are viable, but hot-melt adhesives are typically used and those based on styrenic block copolymers are favored. Of the types of block copolymers available, styrene-isoprene-styrene (SIS) block copolymers are preferred. By raising the modulus, the end-block resin also helps to hold the elastic strands in place. If the elastic strands slip or creep, the laminate will lose elasticity. Thus, the adhesive must hold the laminate together and prevent the bonded elastic strands from creeping. End-block resins are limited in supply, high in odor, and tend to reduce adhesion. Thus, the elimination of end-block resins would be useful. SIS polymers can be used to eliminate the need for end-block resins.