Performance requirements for packaging plastic film

First, good barrier properties

The plastic film for packaging should have good barrier properties to prevent the penetration of oxygen and water vapor phase liquids. As a film for food packaging, it is generally required to block oxygen and bacteria in order to extend the shelf life. For packaging films such as meat, chocolate and biscuits, the barrier to water vapor is very high, because meat and chocolate will dry out if they lose water, and biscuits will deteriorate if they absorb water. In addition, the film packaging metal parts should be able to block oxygen and water vapor, because the conditions of the metal parts are trapped by the oxygen phase water. The bitter LDPE film is permeable to oxygen and water vapor and must be compounded with a barrier material if it is to be used in a barrier package.

Second, heat resistance

Some food packaging requires high temperature sterilization, which requires a plastic film that is resistant to 100 °C.

Third, cold resistance

Many foods need to be refrigerated or frozen. For example, the refrigerator compartment is 2-8 ° C, the freezing temperature can reach 18-34 ° C, and some films will become brittle at low temperatures, which can not meet the requirements of use, but should be used at low temperatures. film.

Fourth, heat sealability

According to the requirements of storage, transportation and automated packaging, the film is required to have heat sealability, the heat seal temperature is low and the heat seal strength is high.

Fifth, better mechanical properties

High mechanical strength films are suitable for mechanized and automated packaging lines for storage and transportation. The strength of the film is high and can be correspondingly thinner, thereby reducing costs.

Sixth, printing performance

Printing is mainly for decoration and promotion. Modern market competition requires packaging films to be easy to print and lasting.

Seven, transparency

In the packaging of food, clothing and some daily necessities, it is required to display the goods in order to facilitate the selection of customers. This requires a higher transparency of the film.

Eight, health

Some packaging films can erode some chemicals that are harmful to the human body and cannot be used as food and pharmaceutical packaging. Ordinary soft polyvinyl chloride film has long been known because of its high content of vinyl chloride monomer in its resin, the use of plasticizers and stabilizers that do not meet hygienic requirements and cannot be used as food packaging. Recently, it has been found that antioxidants in polyolefin films (such as dibutyl-based toluene or BHT) are also harmful to human health, and it has been suggested to use vitamin E as an antioxidant.

Nine, operating performance

Automated packaging lines require good mechanical properties, good openness and a suitable coefficient of friction, which are called film handling properties.

X. Appropriate shrinkage

Due to the development of heat shrinkable packaging, it is required that the shrink film must have and the lower the shrinkage temperature, the better.

11. Energy saving, easy disposal of waste and low cost

From the perspective of energy conservation, the process of manufacturing thin films should be as low as possible. Low-cost films are more competitive and can be accepted by users. Therefore, with the same strength, thinner films can be used to save energy or reduce costs. advantageous. In addition, a large amount of film waste poses a threat to the environment, and plastic film is not easy to rot and is not easily degraded by organisms. Therefore, how to treat waste film and whether it is easy to handle is a problem that film research and manufacturers should pay full attention to.