Process control points of solvent-free composite nylon cooking bag
release time:2019-03-14
Browse times:2993
1. Printing control before compounding
A. High-temperature cooking and solvent-free composite products should be used in the amount of color ink and curing agent.
Generally, the ink manufacturer will give a reference ratio when providing the ink. At the same time, the color printing factory should make a small test before the production, if the amount of the curing agent is too small, the crosslinking degree of the curing agent and the resin is low, the adhesion strength of the ink layer, Heat resistance and hydrolysis resistance will decrease; if there are too many curing agents, excessive crosslinking will occur, affecting the crystallization and micro phase separation between the polymers, the cohesive force of the rubber layer will increase, and the ink layer will shrink excessively, causing delamination. It will also cause more operational problems, such as the bag will become harder after the composite.
B. The film should be fully cured before compounding.
The high temperature resistant solvent-free glue layer may react with the ink layer, resulting in insufficient curing of the ink cross-linking, and layering with the film in the subsequent cooking. Therefore, the printed film should be fully matured before compounding.
C. Avoid mixing different types of inks.
D. Control the use of old ink.
2, composite control
A, high temperature cooking solvent-free glue should choose a good resistance to medium (heat, freeze, acid, alkali, salt, oil, spicy, etc.) and non-toxic, no odor, good health and safety models.
In fact, high-temperature cooking and packaging has always been a difficult point in the field of solvent-free composites, and it has become a hurdle in the process of promoting solvent-free composite processes. In fact, high-temperature cooking packaging to successfully achieve a solvent-free composite process, the most critical is the development of a solvent-free composite glue that can be used in high-temperature cooking packaging. Solvent-free glue that can withstand high temperature cooking packaging has become the focus of many glue companies.
B. The distribution ratio of the glue group should be reasonable when the solvent-resistant composite is resistant to high temperature cooking. Although the glue manufacturer will give a glue ratio, but it is often a theoretical or theoretical ratio. In order to achieve a good composite effect, we must carry out experimental verification and find a matching ratio with other materials and environment, that is, It is necessary to ensure that the cross-linking of the curing agent and the resin is sufficient without excessive cross-linking, thereby avoiding delamination and stratification of high-temperature cooking.
C. High-temperature cooking solvent-free composite phase is more common than ordinary products. First, it is necessary to pay attention to ensure uniform mixing, avoid local excessive cross-linking curing and low degree of local cross-linking, resulting in high-temperature cooking stratification. Second, pay attention to glue and mixing. The temperature of the glue and the rubberizing roller keeps the glue at a proper viscosity to ensure the amount of sizing during the compounding process.
3, ripening
Compared with common solvent-free composite low temperature and room temperature curing, high temperature cooking solvent-free compounding should pay special attention to the process design and management of the curing process, and the design of the curing temperature and time should be reasonable to ensure sufficient ripening.
Some of our test operators, for the previous test of a solvent-free glue, it is recommended that the curing temperature should be above 55 °C, the curing time should be extended above 96h, the door of the curing chamber should not be opened and closed frequently, as much as possible in the composite film. Do not open the door afterwards, until the specified time, fully mature and then take out.
According to the operating experience, if a product can not be fully cured at one time, the peeling force of the secondary ripening is much worse than that of a fully ripened peeling force, and it is easy to stratify and lead to high-temperature cooking stratification.