History shellac

Shellac has had a commercial history similar to that of the traditional resins. It has been replaced by synthetic resins in many applications. In the 1950s, about 19,000 t of various grades of processed shellac were available in the United States. The volume was about 5,500 t in 1995. The largest importer of shellac is William Zinsser Company, Inc. The superior grades of shellac are sold for about 6.60— 9.90/kg, depending on quality. 

A review of polymer history is beyond the scope of this paper and several such reviews are available. Most early polymer applications were modifications of poly(peptides) or poly(saccharides), although some other classes of natural polymers found utility. For example, shellac is a natural poly(ester) derived from from the excretions of the insect Lac-cifer lacca. While these materials were not recognized as polymers until... 

Plastics are made up of polymers and other materials that are added to them to give the desired characteristics. Natural polymeric materials such as mbber, shellac and gutta percha have a long history as raw materials for man. The first thermoplastic, celluloid, was also manufactured from a natural product, from cellulose. Even today, there are still some cellulose based plastics, i.e., the cellulose acetates (CA). Cellulose is already composed of the large molecules that are characteristic of plastics (macromolecules). However, to manufacture CA plastics, they still have to be prepared with acetic acid. The first injection moulding machine was built and patented in 1872 in order to mould cellulose materials. 

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