The necessity of research and development of improved water-based acrylic adhesive

Currently, water-based acrylic adhesives are the most widely used alternative to oil-based adhesive products. The reasons for this are as follows.

They generally adhere very well to a wide range of materials and have excellent weathering and low-temperature resistance properties. In addition, they are emulsion-based adhesives with cross-linking capability, thus offering compatibility with other polymer emulsions, good adjustability, and workability due to their wide viscosity range, and can have a high solids content. To solve these problems, the content of solids can be increased and special beads of raw materials can be used to improve the production speed and adhesion. However, these practices are economically ineffective due to the increased cost of raw materials and the excessive residues after the high-temperature production process can cause other problems in the reassembly process.

Even though conventional emulsion-based adhesives contain the same polymeric components as solvent-based adhesives, they are slightly inferior in terms of adhesive performance (e.g., adhesion, cohesion, shear, and heat resistance). One of the reasons for this is the different mechanisms of mucous film formation. In the case of drop-in adhesives, the continuous film is formed when the organic solvent evaporates from the homogeneous solution. In the case of emulsions, the film is formed when the water dries out of the discontinuous system of emulsion particles. In addition, emulsion-type adhesives contain low molecular weight substances, such as surface activators or defoamers and viscosity modifiers (usually tackifiers), which are detrimental to their adhesive properties.

Although it depends on the method and process used to form the film, these phenomena can cause emulsion adhesives to have reduced moisture and water resistance, adhesion and other adhesive properties compared to solvent-based adhesives, for which polyethylene (PE) films have been widely used as substrates for tapes.

However, because of its low melting point, its use in the manufacturing process of Braun tubes at temperatures above 200°C is very limited, it is not possible to dry quickly, the preparation process is time-consuming, and its adhesive state may be easily changed again by melting the adhesive.

The availability of improved aqueous acrylic adhesives not only solves these problems but also allows the use of high-quality blast tapes for fixing braunschweiger tubes.