Premature Curing

Premature Curing

 

(also scorching), an irreversible reduction in the plasticity of rubber stock, which can occur during manufacturing, processing (for example, during calendering), or storage. Premature curing is caused chiefly by the interaction of raw rubber with vulcanizing agents in the stages of the production process that precede actual vulcanization. As a result, it is difficult, and sometimes impossible, to process the stock into a product. Retarders, or antiscorching agents, are introduced into the rubber stock to prevent premature curing. Phthalic anhydride and N-cyclohexylthiophthalimide are examples of retarders.

References in periodicals archive ?
The maximum injection pressure, low pressure drop and the premature curing or scorching temperature are the criteria to select the mixer design.
If the part in figure 1 has two filling issues where the parts have weak weld lines from scorch (premature curing at a weld line), and the mold tends to flash, but the issues only occur 20% of the time, the goal is to determine which process parameters are most closely tied to these problems.
The patch is covered with a removable flexible polyethylene or polyethylene terephthalate film preventing premature curing. The fibers can be woven or nonwoven glass, carbon or aramid fibers.
One of the materials could not completely fill the cavity due to premature curing (Fig.
An auto purge function prevents premature curing of the material when the dispenser is not in operation.
The inorganic sand mixture reacts to the loss of moisture with premature curing. To avoid the effect, the sand should be held at a temperature close to that of the mixer.
In addition to the obvious benefits of reduced heat output, lower power consumption, and prolonged life, as compared to traditional halogen lights, LED lighting allows the ability to suppress blue light, which causes premature curing of dental resins.
This air-free dispensing method essentially eliminates the problem of premature curing with air/moisture sensitive products.
As more and more cheaper pigments are available to the pigment manufacturers from Southeast Asian sources, we have to be careful about the impurities in those pigments, as the contaminants could cause the premature curing.
Moreover, the temperature control present charring and premature curing to significantly reduce waste.
During transport the liner was covered and iced to prevent premature curing.
He says he had a difficult time finding a machinery manufacturer to work with him because of the premature curing, charring and maintenance problems associated with PUR adhesive.