Currently, steaming and sterilization packaging is mainly divided into two types: plastic and aluminum-plastic structures. According to the requirements of GB/T10004-2008, the cooking conditions are divided into two levels: semi high temperature cooking (above 100 ° C to 121 ° C) and high temperature cooking (above 121 ° C to 145 ° C). Solvent free adhesives can now cover cooking sterilization at 121 ° C and below.
In addition to the well-known three/four layer structure, the main materials used are PET, AL, NY, and RCPP. There are also some steaming products with other material application structures on the market, such as transparent aluminum coating, high-temperature steaming polyethylene film, etc. However, they have not been used on a large scale or in large quantities. The basis for their widespread application still needs longer time and more process inspections.
Application cases and process points
In the field of high-temperature steaming and boiling, our glue has been applied in the four layer structure PET/AL/NY/RCPP packaging of meat products and glutinous rice and lotus roots, all of which can achieve cooking and sterilization at 121 ° C. The applications in plastic structures include WD8166 in 121 ° C NY/RCPP composite applications, which have been widely used and mature; Aluminum plastic structure: The application of WD8262 at 121 ° C AL/RCPP/is also quite mature.
At the same time, in the cooking and sterilization application of aluminum-plastic structure, the medium (ethyl maltol) tolerance performance of WD8268 is also quite good. In addition, WD8258 has shown good performance in the dual nylon cooking structure (NY/NY/RCPP) and the AL/NY (NY is a single corona discharge) layer in the four layer aluminum foil cooking structure.
Process precautions：
Firstly, the setting and confirmation of the adhesive amount should be carried out. The recommended adhesive amount for solvent-free adhesives is between 1.8-2.5g/m ².
Ambient humidity range
It is recommended to control the environmental humidity between 40% -70%. The humidity is too low and needs to be humidified. High humidity requires dehumidification. Because a portion of the water in the environment participates in the reaction of solvent-free glue, excessive water participation can reduce the molecular weight of the glue and cause certain side reactions, thereby affecting the high-temperature resistance performance during cooking. Therefore, it is necessary to adjust the configuration of A/B components slightly in high temperature and humidity environments.
Parameter settings for device operation
Set tension and adhesive ratio according to different equipment models and configurations.
Requirements for raw materials
Good flatness, good wettability, shrinkage and even moisture content of the film are all necessary conditions for completing the cooking of composite materials.
Future development：
Using solvent-free technology for high-temperature cooking packaging, it has:
1.Efficiency advantage, production capacity can be greatly improved.
2.Cost advantage: The amount of solvent based high-temperature cooking glue applied is large, basically controlled at 4.0g/m ² Left and right, the limit is not less than 3.5g/m ²， But the amount of glue applied to solvent-free cooking glue is 2.5g/m ² Some products even weigh less than 1.8g.
3.Advantages in safety and environmental protection
4.Energy saving advantages
In summary, due to its unique characteristics, solvent-free adhesives will have a wider range of applications in the future with the collaborative cooperation of color printing, adhesives, and composite enterprises.
Post time: Mar-11-2024