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Number of plasticizers selected for PVC blown film

by:LINYANG     2020-01-14
The number of plasticizers selected for polyvinyl chloride blown film

The softness of the film is largely determined by the proportion of plasticizers in the formula. Generally speaking, the more plasticizers, the better the softness and low temperature performance.

The so-called low temperature impact compression temperature is based on the issued standard HG2-165- 65 regulations are carried out, which means that at low temperature, a certain energy hammer is used to impact the compressed sample, and the temperature at which the rupture rate is 50% is calculated. It can represent the dynamic state during use (Such as snow and other loads)Low temperature performance. The lower the low temperature impact compression temperature, the better the low temperature performance. The low-temperature performance is not only related to the quantity of plasticizers, but also to the variety and collocation of plasticizers.

not only that, the aging speed is relatively slow after the plasticizer is increased. For example, if 45 parts of plasticizer film is added to the formula, the low temperature elongation will be reduced to 2. 120 days after outdoor exposure. 5% or so. However, for films of the same formula, if the plasticizer is increased to 50, the low temperature elongation after 120 days of exposure can still be maintained at about 5%. Therefore, under the condition of cost permitting, it is beneficial to increase the proportion of plasticizer in the film.

but we should use'Divided into two' From the point of view, the blow molding process will cause great difficulties after the plasticizer content increases. Because the material is too soft, the bubble in the blow molding process will droop down, resulting in sticking to the opening film and damaging the normal operation. At the same time, too much plasticizer will make the two layers of blown film Stick and cannot be peeled off, which is very unfavorable to the packaging film. It has been proved that the viscosity of blown film is directly proportional to plasticizer content and inversely proportional to film thickness. The plasticizer content increases and the viscosity also increases. The larger the film thickness, the smaller the viscosity. Of course, viscosity is also related to the cooling conditions in the production process, so the use conditions of the film must be considered when determining the content of plasticizer in the formula.

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