The glue is applied to the surface of the adherend by a suitable method and tool. Whether the glue is applied correctly or not has a great influence on the quality of the bond.

The difficulty of coating epoxy resin has a great relationship with the viscosity. For solvent-free epoxy resin, if the viscosity is too large, or it becomes sticky due to low temperature, it is difficult to apply, and the adherend can be adhered. The surface is preheated by a hair dryer or other means, and preheated to 40~50 °C, so that the adhesiveness of the coated epoxy resin is lowered, and the surface to be adhered is easily wetted. If it is a solvent-based epoxy resin, the viscosity is too large, and it can be diluted after being diluted with a corresponding solvent to facilitate wetting.
(1) Glue pass count

The number of passes of the glue varies depending on the nature of the epoxy resin and the adherend. Like solvent-free epoxy glue and dense adherend, it can be coated once, and most solvent-based epoxy glues and porous adherends or glue layers requiring a certain thickness need to be glued 2~3 all over. For multiple passes of glue. Be sure to apply the next time after the first time the glue is dry, so don't worry too much.
(2) Glue amount

The amount of glue applied is also related to the variety of epoxy glue and the type of adherend. The amount of glue applied to the porous adherend is larger. The size of the glue directly determines the thickness of the glue layer. Generally, the thinner the glue layer, the less defects, the smaller the deformation, the smaller the shrinkage, the smaller the internal stress, the higher the bond strength, the thinner the layer should not be thicker, and the glue layer is too thick. It is not only useless, but harmful. therefore. Under the premise of ensuring no glue shortage, the glue layer should be as thin as possible. It is generally considered that the thickness of the adhesive layer is controlled to be 0.08 to 0.15 mm.
(3) Gluing method

The method of applying the glue varies depending on the form of the epoxy resin. For liquid, paste or paste epoxy glue can be brushed, sprayed, dip coated, bladed, rolled, injected, etc.
1 brushing method

The method is to apply a glue to the surface of the adherend with a brush. The brushing method is suitable for painting any surface of the shape. For the transformer core insulation black paint LD-2055, the brushing should be in one direction, do not reciprocate, the speed is slower, so as not to bring in air bubbles.

2 spraying method

The method uses a special glue gun to spray the glue onto the bonding surface by means of dry compressed air. The spraying characteristics are uniform thickness of the glue layer, high production efficiency, and suitable for large-area bonding. For large-area pool waterproof products - Liding waterproof paint construction process, construction can be carried out by spraying.

3 dip coating

The method is a process for dipping an adherend into an epoxy resin solution for dipping. For the dip coating of epoxy resin, it is mostly used for the application of insulating paint such as LD-401/LD-401-C. The coil is immersed or dripped in the glue to achieve full filling of the insulating varnish between the coil gaps. To the role of insulation and sealing. The dip coating method is suitable for small, thin and complicated adherends, and has the advantages of simple equipment, low glue consumption and high production efficiency. The dip coating method commonly used is a manual method, a rotary dip coating method, a centrifugal dip coating method, a vacuum dip coating method, a transmission dip coating method, and the like.

4 scraping method

The method is a squeegee that scrapes a paste or paste of epoxy resin to the bonded and sealed portion. For Liding adhesive steel, the paste-like structural adhesive can be evenly applied to the surface to be bonded by the doctor-coating process, and the structure reinforcement can be achieved after the later bonding-curing.
5 roll coating method

The method uses the roller to first dipped into the glue and then transfers to the surface to be bonded or coated. When the surface of the wide flat object is glued, it is more convenient to operate with a rubber roller, and the roller film is relatively uniform. There is no sag, but the corners are not easy to roll and need to be brushed. The scope of construction products includes: waterproof paint, colored pavement adhesive, ground insulating paint and so on.

6 injection method

The method is to pass the epoxy resin glue through a special container and inject it into the joint by hand, mechanical or pneumatic pressure, to be bonded or to be sealed. For example, using 50ml of LD-EP706 or 400ml Liding planting rubber, it can be packed through the rubber cylinder. In the later stage, it can be directly glued by glue dispenser or glue gun, which can not only reduce the post-mixing process, but also improve the curing surface effect and speed up production. speed.

Regardless of the method of applying the glue, it must be carried out carefully and carefully, requiring uniform coating and avoiding air intrusion, and finally obtaining a glue with no suitable thickness, no glue, no bubbles, no accumulation, and a proper thickness after bonding. Floor. If the viscosity of the epoxy resin is too large, the viscosity can be appropriately reduced by heating or formulation improvement, and the adhesion and penetration properties of the epoxy rubber can be improved to ensure the bonding strength. In terms of the rubberized surface, in principle, the surface of each adherend should be uniformly coated to ensure sufficient wetting, but for large-area, low-strength bonding, it can also be applied by spot coating, thread coating or spotting. The method of applying the wire and applying the glue is to save the glue and save labor.