Plastisol heat exposure

The plastisol is converted to a homogeneous solid ( vinyl ) product through exposure to heat [e.g., 350°F (176°C)], depending on the resin type and plasticizer type and level. The heat causes the suspended resin to undergo fusion—that is, dissolution in the plasticizer (Figure 2.42)—so that on cooling, a flexible vinyl product is formed with little or no shrinkage. The product possesses all the excellent qualities of vinyl plastics. 

In cases where viscosity-ternperamre behavior is of less concern, the plastisol can be coated on a glass or stainless steel sheet to the desired thickness using a wire-wound bar, or onto backing or release liner by means of a laboratory coater. Samples are then placed in a circulating air oven at, for example, 190 °C for various time periods. Physical property measmements are then used to determine fusion time. Additional exposure can be used to measure static heat stability. Such measurements can also be carried out with the Metrastat apparatus. 

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