PEN helps accelerate the plasticization of beer bottles

Since the synthesis of PEN in the 1940s, PEN has been waiting for the opportunity to be discovered by the market for 50 years. In 1993, PEN's excellent overall performance began to attract special attention.

PEN's high barrier properties help accelerate the plasticization of beer bottles

Application progress of PEN

The structure of PEN (polyethylene diformate) is similar to that of PET, except that the benzene ring is replaced by a ring, but it is superior to PET in almost all aspects: its barrier property is about five times that of PET, and its heat resistance Chemical resistance is better.

With the breakthrough of its raw material synthesis technology of 2,6-dicarboxylic acid, foreign famous ICI, Shell, Amoco, Eastman and other chemical companies have been producing and accelerating their application research. Currently used in food, beverages, pharmaceuticals, cosmetics, etc., such as small-sized carbonated beverage bottles, fruit juices, mineral water, milk, beer bottles, baby food (potable sterilization) packaging, requiring high barrier, radiation resistance and chemical resistance Drug-based pharmaceutical packaging requires high strength, impact resistance, chemical resistance, and high barrier industrial packaging. In beer and beverage packaging, it has made up for the defects in PET and glass and has become a hot topic in recent years.

Some countries in Western Europe have already begun to use PEN beer bottles in the market. Their preservation effect is the same as that of glass bottles. It is impact-resistant and easy to recycle. In recent years, China has also conducted some researches. For example, the product technology development center of Yizheng Chemical Fiber Co., Ltd. performs PEN synthesis and process optimization, and Guilin Electric Science and Technology also tries to synthesize PEN. At present, the development of raw material synthesis technology is not mature. Many research institutes in China are conducting research, but no breakthrough has yet been made. In addition, companies plan to introduce foreign raw material production technologies to further synthesize PEN.

In spite of the considerable improvement and improvement of PEN synthesis technology in recent years in foreign countries, the application cost is still high, so alloying has become one of the effective ways to expand the application range of PEN. On the one hand, under the premise that the PEN performance is not changed, the production cost is reduced. On the other hand, under the condition that the price increase is not much, the barrier property and other properties of the alloy are greatly improved. The current PEN alloying research has become a hot topic in the packaging industry. Because PET is similar to PEN in structure, rich in sources and cheap, it is widely used in the packaging industry. Therefore, PEN/PET alloys are the most studied. The key to the PEN/PET blend molding is the compatibility of the two, and its measurement index is the transesterification rate, so it is very important to choose a reasonable transesterification rate. PEN/PET alloys can be modified on a stretch blow molding machine for PET to produce containers; copolymers of high PEN content and PET are copolymerized to form a variety of block copolymers that can be conventionally stretched, blow molded, injected The equipment is processed so that PEN is in a better position in the packaging field. At present, the use of PEN/PET copolymers and blends can make heat-resistant bottles, high barrier bottles, UV absorption bottles, thermoforming containers, and the like.

PEN and beer

PEN is considered to be the most suitable material for beer packaging, especially when it is found that the barrier properties of PEN are much higher than those of PET, the industry generally believes that the spring of PEN has finally arrived.

However, after years of waiting, the spring that belongs to PEN is only one or several brands in a small area of ​​the European market, and it can only be used as a packaging for high-end beer.

In order to give full play to the special role of PEN, various materials related to PEN have been introduced continuously, such as PET/PEN/PET composites, PEN and PET compounding materials and many other different combinations of materials, trying to be used for beer packaging. And many manufacturers have launched similar beer packaging materials. However, various improved high barrier materials have not reached the same beer packaging effect as PEN.

For beer companies, even if the cost of a penny increases, it will be quite huge. Therefore, cost control has become the focus of bottle suppliers and beer manufacturers. In this case, the use of PET in the packaging of plastics for beer has seen a trend of far more increase than PEN. More importantly, PEN, as a barrier layer, will also bring about an increase in investment, and it has become more and more embarrassing.

“Using PEN as a barrier layer for beer bottles will increase the cost by approximately 50%, so we use EVOH or nylon as the intermediate barrier.” said Chen Zhiyong, project manager of the New Product Development Department of Zhongfu Industry Group Co., Ltd., “The 180-day shelf life can be guaranteed. The needs have been promoted for use in some beer brands."

Similarly, Invista also introduced bottle materials specifically designed for beer PET packaging using special processes. It is said that single-layer beer bottles made using this raw material technology can greatly improve the barrier properties of PET to oxygen and carbon dioxide gas, and meet all the shelf life standards. This product is designed with a special active oxygen barrier device. Since CO2 does not react chemically with other substances, nylon is mixed in the material to achieve good CO2 resistance.

According to Wang Yanfeng of Italian SIPA company, “For plastic bottles for beer packaging, only two methods are needed to achieve popularization as soon as possible. One is that the government or the government prohibits the use of glass bottled beer; the other method is to reduce the cost of packaging materials to existing packaging. Equivalent to or lower than the cost of glass packaging."

Therefore, after nearly a decade of development, the application of PEN in beer packaging is still only in an awkward position.

PEN and barrier film

While paying attention to the application of PEN in the beer packaging market, raw material manufacturers have also begun to actively explore their uses outside beer packaging. The high barrier film is one of the major aspects.

DuPont Teijin Film Japan plans to increase sales of PEN film. The field of application that is now being fully developed is the flexible printed circuit (FPC) for automobiles, which is expected to be used as a replacement for polyimine films due to outstanding performance and low cost.

With the development of hybrid fuel vehicles in the future, the application prospect of this product will be very good. Due to the insufficient heat resistance of the PET film and the too high cost of the polyimine (PI) film, PEN provides a new market opportunity.

PEN film has outstanding heat resistance, dimensional stability, durability and good airtightness. Due to the balanced performance of all aspects, application is very easy. PEN film can withstand high temperatures of 160 °C, much higher than the 120 °C level of polyester film, while gas permeability and water absorption are lower than PI film. Europe has begun to use PEN film in FPCs for parts such as car dashboards and seat sensors.

Due to the outstanding performance of PEN, the use of PEN film brings many advantages: For a given temperature, a thinner insulating material can be used, which helps to reduce the cost of insulation and other materials, saves space, and has better design possibilities. Sex and good heat transfer; like PET, easy to handle or fit; can be used like a flat film; can be combined with certain materials to get a high quality, low cost lamination system.

PEN and chemical fiber

Due to its excellent physical and mechanical properties and its wide range of applications, PEN fiber has attracted a great deal of interest from chemical fiber manufacturers. It has invested in the construction of PEN fiber manufacturing plants and developed new products such as DuPont, Teijin, Toray, and Toyobo. Companies such as Eastman, Eastman, ICI, and Hoechst are in the leading position. According to reports, Allied Signal in the United States has a production facility of 200 tons/year, Italy also has a production line, and DuPont is building a fiber plant with a capacity of 40,000 tons/year. In addition, some achievements have been made in the development of new varieties of PEN fibers. For example, Japan's Toyobo and Teijin have adopted the composite spinning process and technology, and have developed PEN/PET composite fibers with excellent performance and low cost. When used in tire cords for carcass materials, the adhesion to rubber is very good. It can also be used to manufacture car seat covers, safety belts, etc.

PEN fiber is a kind of high-tech fiber, because it has more excellent performance than PET fiber: high modulus, good dimensional stability, no deformation, elastic foot, good rigidity, is an ideal textile raw material. Currently mainly used for:

(1) Car anti-collision inflatable safety bag. This kind of safety bag requires small size, light weight, high strength, and good flame retardancy after folding. Fabrics made of PEN fiber can meet this requirement.

(2) Skeleton materials such as tires and conveyor belts. Because PEN fiber has greater resiliency and rigidity, it can meet the requirements of high temperature resistance, fatigue resistance, impact resistance, adhesion, and creep resistance of rubber frame materials, and thus become an alternative steel wire, PA66, PET And other ideal materials.

(3) PEN fiber reinforced material. High-pressure water pipes, steam, fuels, chemicals and other pipelines as well as automotive engine covers and other items are all working in a hot and humid environment and must have excellent mechanical and physical properties. PEN fiber is an ideal reinforcing material for these products.

(4) Filter material. Environmental filter materials generally require excellent heat resistance, chemical resistance, resistance to moisture hydrolysis, and abrasion resistance. The filter material made of PEN fiber has excellent filtration performance and is comparable to polyphenylene sulfide (PPS) fibers. At the same time, PEN filter material has excellent tensile strength over a wide range of PH (acidity degree) values, so it will gradually replace the PET screen, which has been widely used in the field of paper and screen mesh.

(5) Cables. Because PEN fiber has high modulus, high flexibility, excellent chemical resistance, and UV resistance, it is an ideal material for the manufacture of various types of cables. It will be possible to gradually replace PET cables in the future.

(6) Clothing and apparel materials. Because PEN fiber has many excellent properties, it is also ideal for clothing and apparel materials.

In summary, the application of PEN is very broad. We believe that with the breakthrough in the synthesis technology of PEN raw materials, PEN will eventually find its special development space.