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Common problems in blistering of medicinal plastic bottles

Carrie May 29,2019 Share this post:

Pharmaceutical plastic bottles often present some quality problems during blow molding. If we can control its molding process, these defects are minimal. The common problems of plastic bottle blow molding are as follows:


 medicinal plastic bottle

The part of the medicinal plastic bottle will appear white and excessively stretched. This is due to the central temperature attitude or pre-blowing that is formed too early and hits the stretching rod. Others will have wrinkles in the bottom of the bottle, the temperature at the bottom is too high, and the pre-blowing too late pre-blowing pressure is too low, this may be the case, and the flow is too small. The overall thickness of the plastic bottle is thick and thin. This phenomenon is to speed up the pre-blowing time, improve the pre-blowing pressure, and increase the gas flow of the plastic bottle.

What is the blush at the bottom of a medicinal plastic bottle? The preform of the plastic bottle is too cold, the stretching is stopped too much, the pre-blowing is too early or the pre-blowing pressure is too high. There is a magnifying glass at the bottom of the bottle, and there is too much material at the bottom of the bottle. Pre-blowing is too late, pre-blowing pressure is too low. The entire plastic bottle does not look so transparent, it is more turbid, because the solid plastic bottle does not cool enough time. The bottom of the plastic bottle will also exhibit eccentricity, which is related to the temperature, stretching, pre-blowing, high-pressure blowing of the plastic preform. Reduce the temperature of the plastic preform, speed up the stretching of the plastic bottle, check the gap between the rod head and the bottom mold, extend the pre-blowing time, and reduce the pre-blowing pressure. Or delay the high pressure blowing, check if the preform is eccentric.

In addition, the medicinal plastic bottle is particularly prone to deformation, and its wall thickness between the longitudinal wall thickness and the radial wall thickness is too large and is easily deformed. The shrinkage of the position of the mold line of the blow molded container product is more serious than the adjacent position, which is that the cooling rate of the thicker area is much slower than that of the surrounding area. The speed of cooling is different and the deformation is different. This defect is preferably handled by simultaneously controlling the longitudinal wall thickness and the radial wall thickness.

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