Lamination of plastic bags is one of the common problems in packaging. Many people simply attribute the reason of lamination to compound, blindly seeking solutions on compound. In fact, the lamination of plastic bags is a comprehensive problem, which is caused by compounding, curing, product properties and storage environment.
First, compound
Lamination is one of the main reasons for lamination of plastic bags. Composite is the completion of printing, with glue and other auxiliary materials in the dry reproduction machine to compound each layer of film together. In this step, glue is the key.
Glue is an adhesive that composites multilayer materials together. The viscosity and quantity of glue have certain standards, and need to be adjusted according to the characteristics of different batches and different kinds of raw materials. Thin glue and small quantity may lead to bag layering. More glue may lead to poor bag flatness. Therefore, appropriate adhesive and appropriate ratio should be selected to ensure sufficient amount of glue to meet the quality requirements of the packaging bag.
In addition, the network cable roller is to supply glue equipment for composite plastic bags. If the network cable roller is blocked, the amount of glue will be reduced. The amount of glue that was set up is reduced, and the composite plastic bags are certainly not firm, and it is easy to appear stratification.
Second, the curing
The composite film just completed has not been fixed molding, can not enter the processing process, therefore, the need to put the plastic bag in the constant temperature curing room for curing, strengthen the tightness between the layers of the film. Curing time is not enough will also lead to the completion of the packaging bag, each layer of film stratification phenomenon.
General composite products from composite calculation, 7 days after the adhesive will be considered to have close to 100% curing, peeling strength tends to be stable. If the factory reduces curing time in order to meet deadlines or cut corners, it may lead to bag stratification.
Third, the nature of the product itself
Built-in packet if corrosive products, also may result in stratification, such as alcohol, acetic acid, methanol, toluene or ec pesticide, or special food additives such as flavouring agent ethyl maltol, the impact of these different kinds of material of packaging is not the same, solvent type material generally by the migration of the inner membrane permeability, If you encounter aluminum foil or aluminum plating and other high barrier materials, will be enriched on its surface, on another plastic film and adhesive swelling and the two layers of film "spread", resulting in stratification.
Still have a kind of circumstance is, if acid, alkaline material passes through inner layer heat seal film hind and adhesive contact, react with adhesive, hydrolyze perhaps its degradation dropped, the adhesive after breaking chain lost original adhesion performance and bring about stratification.
Four, storage,
Composite packaging bag is a film of different materials bonded together by glue. Under different temperature and light conditions, there will be different degrees of aging. After a long time, there will be the phenomenon of peel strength attenuation and even stratification.
