Taizhou Rimzer Rubber & Plastic Co., Ltd - Professional Supplier of Bottles Packaging.

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Why and How to Crystallize Bottleneck?

Crystallized bottleneck is mostly used for hot-filling to prevent bottle deformating, while the Non-crystallized bottleneck mostly for normal temperature or low-temperature filling. The crystal is whilte, helping bottleneck withstand the temperature as high as 100℃. To ensure that non-crystallized bottleneck not be deformed by heat, it’s wall thickness is generally thicker than the fromer. The inner diameter of non-crystallized bottleneck is about 0.25mm smaller, thoug their outer diameters are close.

Sometimes, the non-crystallized bottleneck is also used for hot-filling, but ask much from filling machine.

Hot-filling PET bottles mainly are produced by methods - one-step blowing and two-step blowing.

In two-step blowing, blow the preforms to 1.5 ~ 2 times the final bottles volume, then shrink them after heating to 200 ℃, to increase the crystallization rate of the bottle. Thirdly, blow them to the predetermined shape on molds at about 100 ℃, Finaly, inject air quickly to shape the bottles. The advantage of this process is the crystallization rate of the bottle is as high as 45%, and the bottle can resistant temperature as high as 95 ℃; However, the disadvantage are the auxiliary equipment big, and cost much to get high heat energy.

The one-step is blow preforms on molds at 80 ~ 160 ℃. Crystallize the bottlenecks by stretching, and inject air to shape bottles. This process is relatively simple. The bottleneck can be crystallized through the crystallization furnace, or inceasing the bottleneck thickness. Its advantages are only need few auxiliary equipment, and cost few on heat energy. At the same time, it can be exchanged with ordinary PET bottle blowing machine. The disadvantage is the bottles can only withstand 85 ~ 90 ℃.