1 Introduction
The large-scale production of transparent granules began in the early 1990s, and the production of transparent granules in China began in the late 1980s. At present, there are large-scale development manufacturers mainly concentrated in the Jiangsu-Zhejiang-Guangzhou-Shenzhen area. Transparent granules are mainly used in the production of edible oil bottles - mineral water
Bottles - cosmetic bottles - profiles and other aspects. Since the transparent granules are hard, direct processing is very difficult, and in order to produce pvc granules that satisfy the hygienic-transparency-impact resistance-processing suitability, it is necessary to add various additives. Therefore, the production formula of transparent pvc granules is particularly complicated, and the production formula is the key to the production of transparent pvc granules.
2. Production of components in the formula
2.1 Polyvinyl chloride resin is the main component in the production of transparent pvc granules, accounting for 80-85%.
2.2 Processing improver
Plastic processing is difficult, in order to improve the processing properties of hard plastics, processing aids must be added. After the processing aid is added, the processing temperature of the product can be increased, and the opportunity for the melt to be thermally decomposed can be reduced.
2.3 heat stabilizer
The processing temperature of PVC is very close to its decomposition temperature, and its thermal stability is poor. In order to improve its thermal stability, a heat stabilizer must be added. The determination of the heat stabilizer system and dosage is the key to the formulation of transparent pvc granules and a difficult point in the formulation system.
2.4 lubricant
The main function is to reduce the friction between the internal molecules of the plastic during the processing and between the plastic and the processing equipment, thereby improving the fluidity of the resin and improving the transparency and smoothness of the product. According to the action mechanism of the lubricant, it can be divided into an internal slip agent and an external slip agent. The internal slip agent generally has good compatibility with the friction during the intermolecular processing. The external slip agent has only limited compatibility and is free between the particles, reducing the friction between the molecules and the processing equipment.
2.5 colorants
2.6 Other additives
In order to produce high quality, good transparency, good heat resistance, high strength, good flow properties, odorless and low consumption, transparent pvc granules are often added with other additives such as fluorescent whitening agents, auxiliary heat stabilizers and Some other modifiers.
3. Formula
The production of transparent pvc granules is a difficult processing technology. The formulation requirements are scientific and precise. There are many kinds of additives used, and the mutual influence is also large. The products produced must have high strength, good heat resistance, high transparency, etc. A series of requirements. After a lot of experiments, with the help of a large number of books, through the test of production practice, the following formulas are considered to be more practical:
Recipe 1. Water bottle
Pvc (SG-7) 100 parts
MBS impact modifier 5-9 parts
Calcium and zinc stabilizer 4-6 parts
Processing aid 0-3 parts
Internal and external slip agent 1-4 parts
Auxiliary heat stabilizer 6-10 parts
Fluorescent whitening agent
a little color
Other amount
Formula 2 for oil bottles
Pvc (SG-7) 100 parts
Impact modifier 10-16 parts
Organotin stabilizer 2-5 parts
Processing aid 0-3 parts
Internal and external slip agent 0-4 parts
Auxiliary heat stabilizer 1-3 parts
a little color
Other amount
4 Conclusion
The production of PVC transparent granules is a complex and highly technical plastics processing process. 'There are many types of additives involved in the formulation (up to 15), and the various additives will interact with each other. The recipe is extremely complicated. Due to the different types of equipment and the selected pigment composition, the processing conditions are different, and there is no constant standard formula. Therefore, we have established a formula series according to the different requirements of different users to meet the requirements of users to the utmost, and in order to reduce the cost of formula, the amount of various additives must be appropriate, pay attention to the mutual matching between additives, additives Localization is achieved as much as possible, so that high-quality and low-consumption PVC transparent granules can be produced.
