[Dry goods] Use of hot melt adhesive for edge banding and analysis of problems

发布时间：2021-04-22 0

Edge banding hot-melt adhesive is a kind of adhesive specially used for the pasting of artificial boards. It is an environmentally friendly, solvent-free thermoplastic adhesive. When the hot melt adhesive is heated to a certain temperature, it changes from a solid state to a molten state. When it is coated on the surface of a wood-based panel substrate or edge-sealing material, it cools to a solid state, bonding the material and the substrate together. What problems will occur during the use of edge-sealing hot melt adhesives?

1. The temperature during edge sealing

Since the performance of edge-sealing hot melt adhesive is affected by temperature, temperature is an indicator that needs attention during the edge-sealing process. The temperature of the hot melt adhesive, the temperature of the base material, the temperature of the edge banding material and the temperature of the working environment (the workshop where the edge banding machine is located) are all very important edge banding parameters during edge banding. On the automatic edge banding machine, because the glue is applied to the base material with a low temperature, the hot melt adhesive will be cured in advance, which will cause the glue to stick to the base material but not firmly. The temperature of the edge banding material base material is best kept at Above 20°C. The working environment temperature of the edge banding machine will affect the curing speed of the glue. Factories often have edge sealing problems in low-temperature seasons. The reason is that the curing speed of the hot melt adhesive at low temperatures accelerates the effective bonding time and shortens. If the feeding speed of the edge banding machine cannot be changed (in most cases), the plate and edge banding material must be preheated to ensure the quality of the edge banding.

2. Treatment of edge banding glue line

After edge sealing, the glue line between the board and the edge band will adversely affect the appearance of the panel furniture. Excessive amount of glue will make the glue line obvious and on the contrary will reduce the edge sealing strength. There are many reasons for the discontinuous or uneven glue line phenomenon. The following factors must be comprehensively considered: the cutting accuracy of the plate. The edge of the plate must be at a 90° angle with its plane; the pressure roller of the edge banding machine Whether the pressure is evenly distributed and the size is appropriate. The pressure direction should be at a 90° angle to the edge of the plate; whether the glue roller is intact and whether the hot melt glue is evenly spread on it. Place in the finishing process to prevent dirty things from contacting the glue line.

3. Hot melt adhesive requirements for base material and edge banding materials:

(1) It is more difficult to seal the edges of the base material rich in grease. Oily substances will reduce the affinity of the board and the glue for a long time, which will greatly reduce the bonding strength and cause the edge band to fall off;

(2) Generally speaking, the temperature of the plate and the edge banding material should be kept above room temperature to ensure the quality of the edge banding;

(3) The moisture content of the board and veneer should not exceed 12%. Excessive moisture content will cause the hot melt adhesive to cure in advance and reduce the wetting performance, thereby reducing the bonding strength;

(4) When the fireproof board is used as an edge sealing material, since its back often has residual substances that are not conducive to bonding, the back of the fireproof board must be treated with universal glue or a suitable solvent before sealing the edge to obtain a good edge sealing effect;

(5) Some PVC edge banding tapes often cause difficulties in edge banding due to poor back-coating treatment.

4. Matters needing attention in the use of hot melt adhesive in the maintenance of the edge banding machine

(1) When the edge banding machine is not working, the temperature of the glue tank should be reduced to about 150°C. On the one hand, it can avoid the carbonization of the hot melt glue at the use temperature for a long time. Keep the glue tank clean and will not cause the glue supply system to block. And reduce the heating performance; on the other hand, it can quickly heat up the glue tank to the use temperature when working again. In addition, more than 2/3 of the glue must be kept in the glue tank, otherwise black charcoal will be produced around the glue tank;

(2) Regularly clean the rubber tank and the rubber tank around the excessive carbon and the residue on the rubber roller will reduce the performance of the heating system and the glue supply system;

(3) If you want to remove the remaining glue in the glue tank, you can put a T-shaped object into the glue before the edge banding machine stops working when the glue is still in the molten state, and then reheat the glue after the glue is completely cooled. The surrounding glue is heated and melted and most of the remaining glue can be taken out with a T-shaped object. Then use a 1:1 mixture of toluene and methylene chloride to clean the remaining glue.