Thermoplastic extrusion half-products

There are basically two families of snack items obtained with thermoplastic extruders the direct expanded snacks and the third-generation snacks produced from pellets or half-products obtained after the sequential cooking and forming extrusion steps. The direct extruded types are subdivided into baked puffs and fried puffs (Rooney and Sema-Saldivar 2003, Serna- Saldivar et al. 2008). 

Third-generation snacks Snack food category also known as half-products or pellets. This includes all intermediate or half-products made via thermoplastic extrusion that need further processing to reach consumers. The resulting pellets are usually fried or baked and flavored before packaging. 

Theres a lot of competition between PS and the other five big thermoplastics LDPE, LLDPE, HDPE, PP, and PVC. Polystyrene continues to lose marker share, but it seems to have a permanent place in some applications, particularly molded foams (for carryout food containers), some extrusions, and sheet and film applications. About half the polystyrene ends up in packaging, 17% in electrical/electronics applications, 13% in construction, building products and furniture, and 7% in medical applications. 

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