PVC film formulation
Poly vinyl chloride is the world’s most widely used industrial time, the most widely used general-purpose thermoplastic. Pure poly vinyl chloride resin decomposition and plasticization temperature is very close, when heated to 130 ℃ ~ 140 ℃, it will break down, release hydrogen chloride, so pure poly vinyl chloride resin can not be processed to produce plastic products, must join the Additives, to improve the performance of PVC in order to obtain different performance, the use of a wide range of products. Therefore, the PVC formula design is the prerequisite for the processing of PVC products and important processes. Compared to other plastic varieties, PVC is the most complex formula, the use of the largest variety of additives, the largest number of plastic. Heat stabilizers, plasticizers, lubricants, fillers, colorants and processing aids and impact modifiers, etc., can be seen in most polyvinyl chloride formulations. In order to achieve more excellent performance of polyvinyl chloride to adapt to more severe application environment, broaden the application of PVC, in some PVC formulations sometimes also often add some special additives, such as antistatic agents, flame retardants , Antioxidants and so on. Polyvinyl chloride formula is the core of polyvinyl chloride resin and commonly used additives, such as stabilizers, plasticizers, lubricants, modifiers and other options and mix, some non-use additives are only given some unique PVC products Performance and use.
PVC blown film is mainly used as packaging materials and agricultural insulation covering materials. As the requirements of agricultural film is relatively high, in order to meet the needs of the vast number of rural areas, to be durable in quality, withstand the wind and rain, the price should be low. Therefore, in the design of agricultural PVC film formula, we must consider the following: First, there is sufficient thermal stability. Extrusion blow molding film processing temperature is relatively high (die temperature of 210 ℃), only in the case of good plasticity in order to blow molding in the nose for the appearance of beautiful and uniform thickness of the product. In order to meet the characteristics of the blow molding process, the formulation must be considered not to decompose at high temperatures. Second, there is a good anti-aging. Plastic film in the use of the process, due to the role of sunlight caused by plasticizer volatile. Due to rain, soil buried, etc. to make plasticizer out. At the same time when exposed to the air for a long time, PVC itself will be in the heat, light and other external conditions under the influence of decomposition of HCL, which quickly heat and photoaging. These effects will make the film degenerate crisp, and finally lose the use of value, so the anti-aging problem of agricultural film directly affect its use, cost. If the same film, the use of life can be doubled, then not only reduce the cost, but also save the material. The main contradiction in the use of plastic film is the anti-aging problem, so it should be the focus of the study, in the plasticizer selection, stabilizer with, and other special additives to add to consider to improve the agricultural film Of the aging resistance. Third, there must be a certain degree of softness, especially in the low temperature to maintain a certain degree of softness. Because the vegetables are used in the field of plastic film season is winter, low temperature, wind, coupled with snow or hail, so if the low temperature of the plastic film is not good, it will break the frozen seedlings. In order to reduce costs as far as possible the use of a wide range of low-cost raw materials, such as petroleum esters and chlorinated paraffin and so on. Fourth is the sticky problem. This is not very prominent on agricultural film, because it is the production season and the use of the season mostly in the winter. Packaging film must be considered hot days sticky problem.
Poly vinyl chloride (PVC) film products, PVC resin molding plastic products, should first control the application of the product requirements, the design of the product of the raw materials for the molding formula. In the formulation of blown film, Ba – Cd metal soap as a stabilizer, coupled with the superplasticizer, epoxy resin, UV absorber composed of stabilizer system, its aging resistance is excellent. In the design formula, the proportion of various additives to be fully considered, it is necessary to consider the film has excellent anti-aging properties, but also consider the characteristics of blow molding process, it is necessary to consider the film has a certain flexibility and low temperature toughness, but also To consider the film can not be too sticky to avoid affecting the use.
Post time: Sep-07-2017