This is because the high viscosity of the slice melt faster than the same temperature viscosity of the chip melt speed is slow; the other hand, high viscosity slices can withstand a relatively high melting temperature and maintain the quality of the product. If the high viscosity of the slice using a lower melt temperature will lead to extended injection cycle, and low viscosity of the slices using a higher melt temperature will lead to screw slippage and product quality degradation, can lead to serious molding. For injection molding, once the process parameters are determined, it is desirable that the viscosity of the bottle stage slice is as stable as possible. If the slice of the viscosity fluctuations are required to continue to fine-tune the injection process parameters, serious conditions will lead to product quality decline. ? DSC melting point polymer dissolves requires a process whose DSC melting point reflects the temperature at the peak of the dissolution process. The actual injection molding in theory can exceed the melting point of 20 ℃, such as water bottle DSC melting point is generally about 250 ℃, so the injection temperature is set to 270 ℃ on it, but the injection in order to improve efficiency, the general actual injection temperature will exceed the melting point of DSC 30 ° C to 50 ° C. As long as the quality of products is guaranteed, the appropriate increase in injection temperature is feasible. The ● Isophthalic acid bottle grade slices in the production process by adding isophthalic acid to achieve the purpose of copolymerization, making the flexibility of the bottle to increase and reduce the crystallization performance, is conducive to the preform processing. At the same time, the amount of isophthalic acid increased by 1%, the melting point of the slice will drop 3 ~ 3.5 ℃. The effect of isophthalic acid on the internal quality of the slices is mainly to change its crystallinity. Different products on the performance requirements of the bottle is not the same, so the amount of isophthalic acid can not be generalized. For example, edible oil veneer weight, wall thickness (usually about 110 grams), the billet cooling speed is slow, it requires the lower the better the performance of the bottle, that is, isophthalic acid content should be as high as possible; and hot filling The bottle needs to withstand 90 ° C
Of the high temperature, hope the bottle has a certain degree of crystallinity to reduce the heat shrinkage, so I hope that the performance of slices of the appropriate high, that is, isophthalic acid content should be appropriate low.
First, raw materials knowledge 1, preface PET (polyethylene terephthalate) is the abbreviation of English Polyethylene Terephthalate. Is the most widely used beverage packaging materials. Because PET can be easily through the rapid cooling method to be basically in the amorphous, highly transparent, easy to stretch the PET products, so as a packaging material PET can be made both two-way stretch packaging film, but also by the amorphous embryo Get high-strength, high-transparent stretch blown bottle, you can also directly extrusion or blow molding into non-stretch PET hollow containers. PET hollow containers, especially stretch blow molding bottles, give full play to PET performance, the contents of a good display effect, performance and cost to compete with other hollow containers. So PET packaging materials are basically used to stretch blow molding, which is the most applications of dozens of milliliters to 2 liters of small bottles, Plastic Spray Bottle Manufacturers, Plastic Bottle Cap Suppliers, https://www.plastic-bottle-manufacturers.com
