Plasticizers in rotational molding

Processing of polymers in powder and liquid form by rotational molding is quite different in all means related to the distribution of the material in the mold. When a solid polymer is nsed, powder particles become soft when a certain temperamre is reached. Hot particles, initially at the bottom of the mold, attach to the mold walls as it rotates and a sintering pro- 

As commented, PVC plastisols are suspensions of emulsion PVC in a plasticizer. Formulations contain components such as pigments and thermal stabilizers, but plasticizers are by far the major component. PVC plastisols are rotomolded to obtain hollow soft articles, mainly in the toy industry. It could be deduced that mechanical properties of these parts are not important, but the finishing operations such as insertion of eyes and hair in dolls heads or mechanisms in arms and bodies, or final assembly, imply big loads apphed to the part, and consequently, the mechanical properties have to be developed to the full. Moreover, the molds used in these apphcations have very intricate shapes, pronounced ribs and comers, and aesthetics and details reproduction is very important in these parts. These complex shapes may involve high tensions in the moldings and corrrphcate the demolding process. To obtain a good thickness distribntion in snch a mold, variables involved in the process have to be at the optimnm. 

Aliphatic polyester of dicarboxylic acid PM632 BASF 

The liquid plastisol is at the bottom of the mold forming a pool of material. When the rotation begins some plastisol is lifted by the cold mold, depending on the initial viscosity of the plastisol and on the rotation speed. When viscosity and the rotation speed 

Most problems with the material distribution on a mold surface are controlled by time. In addition, mold temperature, oven temperatirre, and rotation speed affect behavior of plastisols and their distribution. 

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