BOPA is the abbreviation of biaxially oriented nylon film. It is an important raw material for the production of various composite packaging materials. At present, BOPA has become the third largest packaging material after BOPP and BOPET films. Compared with other traditional films, BOPA film has the advantages of good transparency, high gloss, strong odor barrier, oil and heat resistance. At the same time, because BOPA film is non-toxic and harmless, it has become a hot material in food packaging industry in recent years, especially suitable for freezing, cooking and vacuum packaging.
There are two main manufacturing processes of BOPA in China: two-step method (asynchronous method) and synchronous method. The two-step method refers to the two-step drawing process in the production of BOPA. Generally, the longitudinal stretching is carried out at the same time of adding cushion, and then the two sides of the film are clamped with film clamp, and the transverse stretching is carried out in the stretcher, and then the heat setting is carried out in the stretcher after stretching. The synchronous method is to stretch the extruded plastic sheet in the same drawing machine, simultaneously complete longitudinal and transverse stretching, cold and heat treatment to make film. The synchronous method is similar to the two-step system, but slightly different. The characteristics of BOPA membrane produced by the two processes are different, and the downstream application is also different. The advantages and disadvantages of the two production methods are compared from two aspects.
Firstly, the properties of BOPA films produced by the two manufacturing processes are different. The biggest advantage of the synchronous method is that it can reduce the bow effect. Arched effect refers to the situation that both ends of the film will be warped when it is used to make bags because of uneven stretching, poor balance of film surface and inconsistent heat shrinkage rate of diagonal line. The bow effect can be effectively improved by synchronous drawing, and the BOPA film has the characteristics of good balance. Therefore, BOPA produced by synchronous method is mainly used in packaging market with high requirements for film surface flatness, such as medical equipment packaging. The tensile strength of BOPA film produced by two-step method is 20% higher than that of BOPA film produced by synchronous method, and its elongation at break is about 18% higher. At the same time, the two-step BOPA also has high mechanical strength. In the drop test of plastic industry, the damage rate of BOPA under two-step stretching is far lower than that of synchronous method, which means that the BOPA film produced by two-step method is more suitable for outer packaging of food materials, especially for vacuum and frozen food packaging. With the accelerating pace of life, fast food in supermarkets is gradually accepted by most people. In the future, the demand for BOPA film produced by two-step process will be further increased, and the application prospect will be more extensive.
On the other hand, the two-step method is more popular because the product performance is easy to control and the production operation is more convenient. After two-step drawing, necessary heat treatment and cooling treatment can be completed in the same horizontal drawing machine. The production speed is high, with an average of 200m / min. the two-step production line can reach the production capacity completely or even exceed the production capacity. However, the synchronous production line can only reach 80% - 90% of the actual production capacity, and the enterprises with higher efficiency can reach 90%. At the same time, because the two-step production process is more mature, manufacturers using two-step production can ensure high production capacity and yield. In this way, BOPA film produced by two-step method has more cost advantages than that produced by synchronous method. At the same time, the price of synchronous drawing equipment is much higher than that of two-step drawing equipment. The high cost limits the synchronous method BOPA only to be used in the packaging market with higher price, and also limits the growth of relevant demand.
According to Frost & Sullivan's survey, there are only three domestic manufacturers that can produce synchronous BOPA, while the other two-step production lines are imported. After years of production practice, manufacturers of two-step BOPA production have gradually overcome the shortcomings of large bow effect of two-step BOPA film through continuous exploration and technical improvement without changing the existing strength, thus reducing a series of finished product quality problems caused by bow effect. According to the current testing data and application effect, the surface balance of some products has reached the level of synchronous method products. In this way, the advantages of the two methods can be taken into one, which makes the two-step stretching film have a greater market prospect.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service. The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries. We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.