1) Polyester film technology and its current situation
With the continuous development of our country’s economy and the improvement of living standards. There is an increasing demand for modified polyester films with enhanced technical properties. Although traditional polyester film is widely used. Yet, it is no longer able to meet the diverse requirements of today’s consumers and industries. So, various modification technologies have been introduced to improve the performance of polyester films. Let’s explore some common techniques:
1. Copolymer modification:
Regular PET films lack heat-sealing properties. To address this limitation, copolymer modification was employed. Regular PET film is produced by condensing PTA and MEG using a catalyst and heat. These films are highly crystalline. This will hinder its heat-sealing ability. Copolymer modification destroys the ordered arrangement of molecules. The result is an amorphous copolymer with improved heat-sealing properties.
2. Mixed modifications:
Blending modification involves introducing a certain proportion of other substances, such as PEN or LCP, into the PET film. to enhance specific performance. For example, blending 10-20% of PEN with PET can significantly improve its oxygen and carbon dioxide barrier properties. Increases of 30%-50% and 23%-37% respectively. This modification also extends the film’s UV protection wavelength to 380nm. Making it suitable for applications such as liquid packaging.
3. Multi-layer co-extrusion:
Multilayer coextrusion technology in polyester film production allows different raw materials to be combined according to the performance requirements of the final product. For example, PEN and PET are both polyesters with excellent compatibility. A layer of PEN is added to the three-layer co-extrusion process. Can improve barrier properties, heat resistance, and radiation resistance. Making it ideal for a variety of applications.
4. Surface coating modification:
Applying coatings to the surface of polyester film is a common method to enhance its properties. For example, a clear coating containing UV absorbers can form a UV protective layer. Improve the UV resistance of the film. Also, coatings such as polymer solutions can significantly increase the surface tension of the film. Improve its printability and aluminizing properties. Remains stable even under high temperature and high humidity conditions.
5. Nanomaterial modification:
Nanomaterials have unique quantum size effects, surface effects, and interface effects due to their extremely small size. Incorporating nanomaterials such as silica or nanoparticles into polyester films can enhance their mechanical properties. Reduce thermal expansion and increase transparency. Making these films highly versatile and efficient.
2) Current status of polyester film technology in China
In recent years, China’s polyester film market has undergone significant changes. The industry was initially dominated by general-purpose films. Later it underwent a transition to functional films. Special attention is paid to optical films. This shift is driven by changing consumer demands, oversaturation of the standard film market, and the pursuit of improved living standards. So, manufacturers diversify their product offerings. The result is a wider range of differentiated films. This article takes an in-depth look at the evolution of China’s polyester film market. The factors driving this shift and their impact on product mix are highlighted.
1. Shift to functional films
1.1 The rise of functional films:
Historically, China’s polyester film market has been primarily characterized by general-purpose films used in a variety of packaging applications. But, as the market became saturated with standard films. Manufacturers are beginning to explore new avenues. Demand for functional films. In particular, demand growth in the optical field is strong. The changing needs of consumers, including improvements in living standards. prompting a shift towards films with enhanced technological capabilities.
1.2 Optical films become the focus:
The field of optical films has become a key driver of the transition to functional films. With the rise of consumer electronics and the demand for high-quality displays. Optical films have found their niche. These films are an important component of devices such as televisions, smartphones and tablets. Improves screen clarity, brightness, and viewing angles. The growth of this industry has played a key role in steering the industry towards functional films.
2. The evolution of product structure
2.1 Before 2015: Dominance of general packaging films:
Before 2015, China’s polyester film market was dominated by general packaging films. These films are used for traditional purposes and are widely used in the packaging industry. The market mainly revolves around films designed for basic protection, printing, and simple applications.
2.2 2015 and beyond: Moving to Functional Films:
The turning point came in 2015 when the market for standard packaging films became oversaturated. As the environment and consumer needs change. Manufacturers embark on a transformation journey. A new production line was established. Special emphasis is placed on producing thicker functional films. These films emphasize performance and differentiation. Catering to the changing needs of industries and consumers.
- Diversified and differentiated products:
The shift towards functional films has led to product diversification in the polyester films market. Manufacturers are beginning to offer a wider range of films with unique properties and applications. These differentiated products are designed to meet the specific requirements of each industry. Including optical films for electronic displays, high-performance films for industrial use, and films with advanced technical properties.
- Self-sufficient products:
As the industry embraces this shift, some differentiated products are proving to be self-sustaining. These films not only meet the needs of the domestic market. The export potential has also been demonstrated. These self-sufficient products have contributed to the growth and development of China’s polyester film industry. Strengthened its position in the global market.
With the continuous growth and diversification of China’s polyester film market. Manufacturers must remain innovative and collaborative to close the technological gap with their international counterparts. This approach meets the changing needs of consumers. It can gain a firm foothold in the global polyester film market. It can also provide high-quality and specialized film products for a variety of industries and applications.
3) Technology and production features
Special functional polyester films boast remarkable properties. They are multifaceted mechanical, optical, and physical attributes. They have been seamlessly integrated into numerous industrial sectors. It is widely used in liquid crystal displays, semiconductor lighting, solar photovoltaics, and electronic fields. With the expansion of application scope and the strengthening of import substitution calls. Expectations continue to increase related to quality, performance, and stability. So, film manufacturers must strictly adhere to strict requirements on product formulas, manufacturing procedures, and production equipment.
1. Formula Design
Formula design is an indispensable step in the production of special functional polyester films. According to specific roles and functions, suitable additives and granules are carefully selected. It also includes vary in size and quantity. Formulators must also consider the expected performance characteristics of the product. This process requires extensive experimentation and comprehensive testing of different material compositions. Finally, the optimization of the formula design is achieved. Efficiently achieving requires performance benchmarks.
2. Choice of Stretching Technique
The choice of stretching technology is crucial. These processes are divided into two categories: uniaxial stretching technology and biaxial stretching technology. Currently, biaxial stretching and its ability to enhance film properties are less efficient. People prefer biaxial stretching. Biaxial stretching involves heating and melting polyester chips through an extruder. The material is then stretched longitudinally and transversely. This process aligns the polymer chains. Crystal structures parallel to the plane of the film. Thereby it improves film performance.
3. Production equipment
The production of special functional polyester films requires a set of core equipment. Including extrusion system, casting system, stretching system, and winding system. Extrusion systems convert raw materials from solid to molten state. Also, ensure thorough mixing by means of. It consists of basic components such as an extruder, primary filter, metering pump, and secondary filter. The casting system revolves around the process of casting molten material onto a rotating cooling drum. Generates thick amorphous plates. Stretching, either longitudinally or transversely, is critical to orienting the polymer chains. It produces films with excellent properties. The main components of the stretching system include longitudinal stretchers and transverse stretchers. Finally, the task of the winding system is to roll the finished film onto the mandrel. And it needs to control the roll tension during the winding process. The system includes components such as winding shafts, tension controllers, embossing rollers, flattening rollers, and static eliminators.
As consumer demand continues to expand in everything from LCD displays to solar photovoltaics. The importance of these specialty films has grown exponentially. Manufacturers in this area must maintain their commitment to research and development. At the same time, we insist on innovation. This approach helps meet the growing needs of various industries. It also strengthens its position in the global market as a supplier of high-quality products. Specialized film products can be tailored for a variety of applications.
