Glue is an auxiliary material commonly used for packaging boxes, and its performance and suitability vary. In the packaging industry, white latex, animal glue, and epoxy glue are the most commonly used glues. We will discuss the characteristics of these three types of glue in the following paragraphs.
1. Latex glue
Currently, latex glue is one of the most versatile and largest varieties of adhesives. It can be found in a wide variety of packaging, including mooncake boxes, wine boxes, jewelry boxes, leather boxes, etc. An environmentally friendly water-based environmental adhesive without organic solvents, latex glue is produced by emulsion polymerization, using water as the dispersion medium. The material is fast drying, has high adhesion, is operable, and has high compressive strength. Its physical properties will not change in an environment between -15°C and 60°C, and it is an important component of the packaging box. However, it has poor plasticity and high permeability. Because of its high permeability, if the dosage is too high, it may cause printing color changes, which are often observed during the gluing process. It is therefore very important to select the right kind of paper and to ensure that the glue quality and amount are adequate. As well, if the design requires hot stamping, try to hot stamp the film, so as to isolate the latex and aluminum foil, as this will prevent their reaction and result in the gold color turning black, which should be taken into account when designing the printing process.
2. Animals glue
This type of glue consists primarily of animal protein, does not contain benzene or formaldehyde solvents, is non-toxic and environmentally friendly, and will not cause food or packaging to become polluted. Generally, in production applications, gold & silver card paper is preferred, as its laminated flatness and stability are superior to coated paper. Packaging laminated with it will not be deformed, will be flat and mold-free, and can also improve the stiffness of paper products. There is a certain degree of softness in addition to strong adhesion. It should be noted that this glue has no capability of adapting to high temperatures and high-humidity environments. Long-term high temperatures will cause the edges of laminated packages to warp and separate, which will result in local blistering. As a result, when using this glue, it is essential to take full consideration the environment in which the package will be used.
3. Epoxy glue
Which is often used for bonding metal, rubber, plastic, wood, ceramics, packaging, fabric, and leather, among other things. It is a one-component adhesive, a light yellow viscous liquid. The epoxy glue is capable of curing at room temperature, has a high viscosity, is impact-resistant, water-resistant, and acid and alkali resistant. In the packaging box, it is mainly used for the assembly of accessories. However, the material requires greater levels of time and space to cool and dry, which reduces its efficiency of production; secondly, it is not highly resistant to high temperatures, has an unpleasant odor, and melts at temperatures above 50°C, which may result in the accessories falling off. It is therefore not recommended to use this type of glue in cosmetics and food packaging boxes.
To select the right glue for production use, it is important to consider the client’s requirements, the packaging material, the assembly of accessories, and other factors. Food packaging should be considered environmentally friendly, non-polluting, without odor penetration, and without contaminating the food. Animal glue has obvious advantages in this regard. When it comes to light industry products, white glue is the best choice because it will not be affected by temperature changes in the environment. It is possible to choose the appropriate glue based on the actual situation.
