Animal glue flexible

MMM-A-001993 Adhesive, Epoxy, Flexible, Filled. MMM-A-100 Animal Glue. 

Technical gelatin and animal glue, on the other hand, have seen their market share considerably eroded in the last 25 years. This decline has been brought about by the advent of synthetic polymers, which have taken over the sizing of synthetic fibers and the binding of paperback books. (But telephone books and catalogs have stayed with animal glue because of its superior durability and flexibility as well as lower cost.)... 

Early hot melt adhesives were based on ethyl cellulose and animal or hide glues. These were later replaced by synthetic resins such as polyamides and ethylene-vinyl acetate copolymers. More recently a new class of compounds, referred to as block copolymers because of their unique chemical structure, have emerged. These latter compounds are copolymers of styrene and butadiene, isoprene, or ethylene-butylene which tend to widen the flexibility property range of hot melt adhesives. They probably represent the fastest growing segment of the hot melt adhesives market at the present time. Their primary application is in hot melt pressure sensitive adhesives. Polymers based on other than polyolefin resins are discussed in other chapters in this handbook. 

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