Experts, our factory’s apparent density is very high; how can we adjust it to reduce it? I would appreciate some advice!
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Our factory produces PVC using the calcium carbide method, and its apparent density is quite high, around 0.56. Could the experts please advise on how to adjust this?
There are many factors that affect apparent density: 1. As temperature increases, apparent density rises while oil absorption decreases； 2. The pH value of the polymerization system affects the effectiveness of the dispersant, which in turn influences the apparent density and oil absorption of PVC ； 3. Selection of the dispersant: When polyvinyl alcohol is used as the dispersant, the lower the degree of hydrolysis and polymerization (which can be characterized by the viscosity of the aqueous solution), the lower the apparent density of the resulting resin ； Specifically, it still requires experiments; adjustments to the formula can only be made gradually, and experience is of the utmost importance!
To make adjustments to the dispersant formula, the amount of the gel-retaining type dispersant should be reduced. Initially, the total dry weight of the dispersants can be kept unchanged while making these adjustments; after that, the changes in product quality and particle morphology should be observed, and further adjustments can be made accordingly
Hehe, we can invite you to our place; our value fluctuates between 0.51 and 0.53, and it’s not possible to adjust it.
Hehe, I’ll try adjusting it first and share the results with everyone once I have something
It has been adjusted; pay attention to the quality of individual units.
The dispersant with an alcoholysis degree of 88 is used to adjust the apparent value; its amount can be reduced, while that of the one with a degree of 70 can be increased