Flexible packaging polyurethane laminating adhesives are the core materials for film laminating and flexible packaging production. The bonding effect directly affects the sealing, durability and safety of the packaging products. To avoid problems such as delamination, blistering and poor curing, and to ensure production quality and construction safety, the following five key points need to be paid special attention to when using them.
1. Strictly control the mixing ratio. This adhesive is mostly two-component, and the main agent and curing agent must be mixed in the standard proportion. It is strictly forbidden to increase or decrease the dosage at will. After mixing, fully stir for 10-15 minutes, let it stand to eliminate bubbles, and then use. An imbalanced ratio or uneven stirring will result in incomplete gelation of the adhesive and a decrease in bonding strength.
2. Do a good job in surface treatment of the substrate. Before bonding, thoroughly clean the dust, oil stains, and moisture on the surface of the film, aluminum foil, etc., to ensure the substrate is dry and clean. Impurities on the substrate will block the bonding of the adhesive, easily causing quality defects such as glue spots and delamination after bonding.
3. Strictly control the construction temperature and humidity environment. The suitable construction temperature is 5-35℃. High humidity in the environment will cause the adhesive to absorb water and deteriorate, affecting the curing effect. At the same time, avoid direct blowing of the air onto the adhesive surface to prevent rapid formation of a crust on the surface of the glue and reduce the bonding performance.
4. Follow the construction time specification. The mixed glue has a fixed applicable period. It should be prepared in small amounts and used as soon as possible to avoid the increase of glue viscosity and failure due to long-term storage. After bonding, it is necessary to control the temperature and humidity for curing according to the standard to ensure the stability of bonding.
5. Standardize storage and safe operation. The glue should be stored in a cool, dry, and shaded place away from fire sources, heat sources, and acid and alkali chemicals. The remaining glue should be sealed and stored, marked with usage information, and prevent the mixing of deteriorated glue. At the same time, take proper construction protection measures to ensure operational safety.
