In recent years, China has entered the WTO and absorbed foreign experience in food packaging. Instead of simply pursuing the appearance of food packaging, it has begun to pay attention to the nature of packaging, to keep food fresh, to contaminate packaging, and to increase shelf life. The trend can be shown from the development of plastic composite printing industry and high-performance BOPET film in recent years.
First, the development of the plastic composite printing industry is the basis for improving the quality of food packaging:
The development of China’s economy has led to a rapid development of the plastic composite color printing industry. It was reported at the National Plastic Flexible Packaging Conference and related magazines that the level of high-speed multicolor intaglio printing machines designed and manufactured in China in the 1990s was close to the international level. The sales are very good. The annual sales volume is more than 100 sets. Each year, it imports more than 40 sets of various plastic color printing presses. Each year needs more than 500 tons of plastic film. Every year it needs to increase the output of various films to at least 60,000 tons. With the further development of our country’s economy, the further improvement of the people’s living standards and the development of the Great Northwest will provide a good opportunity for the development of the plastic packaging film industry. After joining the WTO, we will keep up with the world level in food packaging and will also increase the demand for BOPET film. In 2000, the consumption of BOPET film in the Americas exceeded 380,000 tons, and it is foreseen to increase at an annual growth rate of 3%. The average annual growth rate of BOPET film in the world is 4 to 6%, although there are some applications in recording and video tapes. Declined, but growth in packaging and other industries exceeded average growth.
Second, the excellent performance of polyester film to meet the improvement of packaging quality
After the SARS epidemic, the majority of consumers paid more attention to the hygienic requirements of food packaging, especially the requirements for the storage period of food, the preservation requirements of food, and the antibacterial requirements for packaging materials. Plastic packaging manufacturers to restore the practical requirements of consumers, from the appearance of beautiful, to practical functional packaging design, restore the true role and significance of food packaging. In this form, the demand for BOPET film with excellent performance has been continuously increased in recent years. At the same time, the quality of food packaging has also been improved, making it unnecessary to increase the printing cost due to the excessive pursuit of appearance, but also reducing the packaging bag's cost. Costs to participate in market competition, manufacturers in the selection of materials to lower performance standards lose consumer trust. We can clearly see from the comparison below.
1. We compare the oxygen permeability of BOPP film and BOPET film, which are the most used in the market today. Oxygen permeability is an important performance of food packaging. If the packaging bag is well sealed, the storage period of food The material's permeability to oxygen is determined, especially for vacuum packaging and oxygen removal packaging.
From the above data can be analyzed, BOPP film packaging food storage period than BOPET film packaging food storage period is shorter, especially at room temperature BOPET film packaging food in the supermarket shelf life than BOPP film shelf life is twice as high the above. However, the fact is that BOPP-packaged foods are the majority. This is because food packaging companies ignore the quality of packaging, and cause foods that exceed the storage period to be pushed into the market and disposal markets, which endanger people's health.
2? Comparison of vapor permeability of organic solvents
Most of the organic solvents are harmful to human health. Therefore, consumers are paying more attention to the protection of their health with the improvement of living standards. In China, today's composite printing is inseparable from organic solvents, especially in China. How to choose a barrier material with a low organic solvent transmission rate is the responsibility of food packaging manufacturers for people's health. In the United States, Japan, and Europe, there are stringent requirements for organic solvent penetration. After China enters the WTO, It has attracted the attention of the composite printing industry. In recent years, the selection of packaging materials has focused on the choice of material properties, which has also promoted the development of high-end packaging materials BOPET film. <BR>
After the aluminum-plated BOPET film shows its superiority, not only to further improve the oxygen barrier, but also make it better than the BOPP moisture barrier, BOPET aluminum permeability after the moisture permeability from the original 40-45 drop To 0.3 to 0.6 and BOPP aluminum plating after the moisture permeability from the original 5 ~ 7 down to 0.8 ~ 1.2 (g/mm2.24h.40 °C - aluminum layer thickness of 60 ~ 70mm).
The large number of BOPET film applications on the packaging increase the strength of the packaging bag and reduce the weight per unit of packaging material, which helps reduce environmental pollution. At the same time, the scope of application of the temperature of packaging materials has been improved, from the packaging of frozen foods to the holding of high-temperature cooking foods.
The application and development of the transparent film of high barrier silicone film with BOPET film vacuum plating will also promote the transparency of packaging in China's food packaging industry, practical application, and development of recycling and environmental protection.
Silicone vacuum-plated BOPET film, also known as soft glass, has the same effect as the glass bottle in terms of product preservation. No long-term storage or high-temperature treatment will produce no odor.
Its barrier properties are the same as that of aluminum plating. Its advantage is that the transparency is basically the same after the silicon plating, so the packaged food can be seen clearly from the outside of the packaging bag, increasing the consumer's credibility and the desire to purchase. .
In addition, due to the temperature resistance of BOPET film (which can be used at 130°C for a long time), the film after silicon plating can be used for microwave food packaging. As people's daily life and work pace is accelerated, lifestyle will also change and microwave foods will be affected. The majority of consumers are welcome.
BOPET film is the most suitable material for vacuum plating of silicon oxide. Silicon oxide evaporated film is deposited on the polyester film by vapor deposition, which means that the increase in barrier properties is caused by the glass layer, so in order to maintain the process of evaporation and after plating In the barrier properties, the glass layer must be kept intact.
The damage of the glass layer is caused by the thermal deformation of the base film during the vapor deposition process. The temperature during the vapor deposition is high, and the material that is not temperature-resistant can cause thermal deformation. After the cooling, internal stress occurs and cracks, which affects the thin film. Barrier properties
During the post-plating process, the required evaporation base film has a good degree of smoothness, so that the film is not easily folded and the glass layer is damaged, which may affect the reduction of barrier properties.
This material can be recycled and reused. Silicon oxide has no effect on the properties of plastics in recycled materials and is therefore also referred to as environmentally friendly material.
Reproduced from: ca.sooq.cn