1. Control of influencing factors of materials
Because of the amide group in the molecular structure of BOPA, its polarity and surface tension can reach 52 Mn / m. when BOPA is used as the intermediate layer of high temperature cooking composite film, the wetting tension of its non corona surface can not reach 48 When Mn / M is higher than m n / m, the composite fastness of non corona surface can not be guaranteed, which is easy to cause the composite film to layer. At the same time, because there are a large number of amide polar groups in the molecular structure, it is easy to absorb water molecules with the same polarity on the surface. When the two-component polyurethane adhesive with high temperature resistance is used for lamination, it is also easy to cause the lamination is not firm.
For rcpp, the first is to pay attention to its surface wetting tension, and it should be tested roll by roll before lamination. If it is more than 40Mn / m, it can be used safely. If it is only 38mn / m, it needs to be verified before it is used; the second is to pay attention to whether there is precipitation on the surface of rcpp film. If there is precipitation, the composite peeling force will be reduced or even layered, and the appearance of composite and product hygiene will be affected Thirdly, the model and formula of the rcpp passed the test can not be changed without the test, so as to avoid the influence of the composite peeling force and high temperature cooking delamination due to the properties of the rcpp not meeting the requirements.
Ink must choose high temperature cooking ink, otherwise high temperature cooking solvent-free composite products in cooking due to poor ink stratification.
2. Process control
1) Printing control before compounding
A. The amount of color ink and curing agent should be appropriate when printing high-temperature cooking solvent-free composite products.
Generally, ink manufacturers will give the reference proportion when providing ink. At the same time, the color printing factory should make a small test before production. If the amount of curing agent is too small, the crosslinking degree of curing agent and resin is low, and the adhesion strength, heat resistance and hydrolysis resistance of ink layer will be reduced; if there are too many curing agents, excessive crosslinking will occur, which will affect the crystallization and micro phase separation between polymers The adhesive layer cohesion increases, the ink layer shrinks too much, causing delamination, which also causes more operation problems, such as the composite bag will become hard.
B. The printing film should be fully matured before laminating.
The solvent-free glue layer of high-temperature cooking may react with the ink layer, resulting in insufficient crosslinking and curing of the ink and lamination with the film in the subsequent cooking. Therefore, the printing film should be fully matured before laminating.
C. Avoid mixing different series of inks.
D. Control the use of old ink.
2) Compound control
A. High temperature resistant cooking solvent-free adhesive should be selected with good medium resistance (heat resistance, freezing, acid, alkali, salt, oil, spicy, etc.) and non-toxic, no odor, good health and safety model. In fact, high-temperature cooking and packaging has always been a difficulty in the field of solvent-free composite, and has become an obstacle in the promotion of solvent-free composite process. In fact, in order to successfully realize the solvent-free composite process of high-temperature cooking packaging, the most important thing is to develop a solvent-free composite glue which can be used in high-temperature cooking packaging. Solvent free glue with high temperature cooking packaging has become the focus of many glue enterprises.
B. The ratio of glue group should be reasonable when high temperature cooking solvent-free composite. Although the glue manufacturer will give a glue ratio, it is usually a rough or theoretical ratio. In order to achieve good composite effect, we must carry out experimental verification and find a matching ratio with other materials and environment, that is to ensure that the curing agent and resin are fully crosslinked, and there is no excessive cross-linking, so as to avoid stratification and high-temperature cooking stratification.
C. Compared with ordinary products, high-temperature cooking solvent-free composite requires attention to ensure uniform glue mixing, avoid local excessive crosslinking curing and low degree of local cross-linking leading to high-temperature cooking delamination, and pay attention to the temperature of glue, glue mixer and rubber roller, so as to keep the glue at a proper viscosity and ensure the glue loading amount in the process of compounding.
3) Ripening
Compared with the ordinary solventless compound curing at low temperature and room temperature, special attention should be paid to the process design and management of high temperature cooking solvent-free composite. The design of curing temperature and time should be reasonable to ensure sufficient aging. Some of our test operators, for the previous test of a solvent-free glue, suggested that the curing temperature should be above 55 ℃ and the curing time should be extended to 96 ℃ The door of the curing chamber shall not be opened and closed frequently. The door shall not be opened or closed after the composite membrane is put in as far as possible until the specified time, and the door can be taken out after one-time curing. According to the operating experience, if a product can not be fully aged at one time, the stripping force of secondary curing is much lower than that of one-time curing, which is easy to layer and lead to high-temperature cooking stratification.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service. The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries. We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.