New choice of plastic for frozen food cartons

In recent years, carton packaging has been replaced with traditional packaging such as plastic bags (boxes) to enter frozen food packaging due to its novel and beautiful appearance, unbreakable, easy to carry, open, convenient for printing, display, recycling, and environmental protection. field.

We know that frozen foods are stored in the freezer for a long period of time and there is a tendency for water vapor to form when the temperature changes. If the adhesion is not strong, the carton is prone to cracking, which affects the aesthetic appearance of the package and the quality of the product. Therefore, choosing the right adhesive in the carton package of frozen food is the key to avoid cracking the carton under low temperature environment.

Adhesives should have the following conditions to effectively prevent carton cracking. The adhesive should have the following conditions: good adhesiveness at low temperatures, soft film, no brittleness, no breakage, and certain water resistance; Resistance to condensate generated due to sudden changes in temperature, and safe, environmentally friendly; The raw materials used in the adhesive should meet the hygienic requirements for food packaging; the cost or cost-effectiveness of the product is within the acceptable range of the customer.

At the same time, the choice of adhesive should be related to the production equipment (such as the equipment used for adhesive gluing and the coating method), the factory environmental conditions (whether the air conditioning system, workshop temperature and humidity, etc. will affect the gluing operation) and Packaging substrates match. The length of fiber in the board or the proportion of recovered pulp, the weight of the surface printing ink, the type of coating varnish, whether the film is covered, and the level of surface energy, etc., will affect the bonding effect, so the The adhesive must match the adhesive substrate.
Correct application of new adhesives Currently, in order to obtain a good gloss and a beautiful appearance, UV varnish and BOPP film are widely used in the packaging of high-end products, and these two types of substrates are particularly difficult to bond. This has led to the opening of plastics, especially at low temperatures. This requires the use of special water-based adhesives. Recently, some newly-developed water-based adhesives have strong adhesion to UV varnish, have wide adaptability to different types of UV varnish, and can be applied to the bonding of BOPP coated carton.

For hot-melt adhesives, hot-melt adhesives are more suitable. Due to the fact that the hot melt adhesive can be quickly cooled and cured to form the following features, it is used in large quantities to meet the requirements of high-speed production lines.

However, since the operating temperature of the conventional sealing hot melt adhesive is usually in the range of 150° C. to 180° C., it is not only prone to scald accidents, but also the interior of the hot melt adhesive machine is susceptible to carbonization of the glue and clogging the nozzle after a long time of use. The maintenance of the equipment will affect the stability of the packaging quality. Therefore, the use of a new type of ultra-low temperature operation of the hot melt adhesive can avoid the above problems and become a new choice.

It is reported that the new ultra-low temperature operation of hot melt adhesive for the bonding of frozen food cartons, bonding performance to meet the storage environment from 30 °C to as low as -40 °C, the operating temperature can be as low as 90 °C. Its advantages are: (1) Lowering the operating temperature can greatly reduce the occurrence of carbonation and clogging of filters, hoses, nozzles, etc.; (2) It can reduce the loss of hot melt adhesive systems, reduce maintenance costs and reduce the number of processes. (3) Improve operational safety and avoid scalding; (4) Reduce energy consumption; (5) Reduce the environmental pollution of food packaging workshops caused by the smoke and odor produced when glue is heated.