In furniture manufacturing, the edge banding and the board are bonded together by hot melt adhesive (adhesive). A physical phenomenon of wetting and mechanical seizure, this bond is affected by environmental conditions, and the following quality problems occur. In winter, the ambient temperature is low, and the temperature of the substrate used for bonding is also low, so the characteristics are greatly affected by temperature.
Pseudo-adhesion is poor; plastic edge banding is mainly composed of thermoplastic resin. When the ambient temperature is low, the hot melt adhesive is coated on the substrate and quickly absorbs part of the heat by the surrounding low-temperature air and the substrate, which shortens the "exposed time" of the hot melt adhesive, and forms a film on the surface. Blocks the progress of hot melt adhesive wetting, resulting in false bonding or poor bonding. Problem The following actions can be taken:
1. Preheat the substrate and raise the temperature of the hot melt adhesive box to 5°C-15°C.
2 Conditions can increase the speed of the edge banding machine.
3. Use hot melt adhesive with long exposure time, good infiltration effect and strong cohesion.
In addition, the low pressure of the edge banding machine will cause an air gap between the contact surface of the hot melt adhesive and the substrate, which hinders the optimal infiltration and mechanical occlusion of the hot melt adhesive and the substrate, and also causes false adhesion and poor adhesion. In response to this problem, the sensitivity of the pressure roller should be checked to show the accuracy of the instrument and the stability of the gas supply system. Adjust the appropriate pressure (thin side 1.5-2Pa, thick side 2-3Pa). In order to avoid false bonding and poor bonding.
1. The edge strip falls off/unsatisfactory tensile strength
Hot melt adhesive is mainly composed of thermoplastic resin and thermoplastic elastomer EVA, which is greatly affected by temperature. When the ambient temperature is low in winter, the hot melt adhesive is coated on the substrate and quickly takes away part of the heat by the surrounding low-temperature air and the substrate, which shortens the "exposed time" of the hot melt adhesive and forms a film on the surface. , which blocks the progress of hot melt adhesive infiltration, resulting in false adhesion or poor adhesion. To solve this problem, you can use the following methods:
①Before edge sealing, preheat the base material;
The ambient temperature affects the bonding strength, and the board must be preheated before gluing and sealing, especially in winter. Before the edge banding operation, the plate should be placed in the workshop in advance to keep the temperature of the plate at the same temperature as the workshop; or the plate should be heated with a small sun lamp one night in advance (heated to 15 degrees), of course, It is best to install heating in the production workshop, but the cost of this solution is relatively high. (If the temperature of the substrate is low, the cooling rate of the adhesive applied to the substrate is too fast, resulting in false bonding between the substrate and the edge band, and the bonding is not firm.)
② Properly increase the set temperature of hot melt glue tank and glue roller;
On the basis of the original set temperature, the temperature of the hot melt glue tank is increased by 5-8℃, and the temperature of the glue wheel is increased by 8-10℃.
③ Properly adjust the pressure of the edge banding machine;
If the pressure is low during edge sealing in winter, it is easy to cause an air gap between the contact surface of the hot melt adhesive and the substrate, which hinders the optimal infiltration and mechanical engagement between the hot melt adhesive and the substrate, resulting in false adhesion and poor adhesion. To solve this problem, the sensitivity of the pressure roller should be checked, the accuracy of the display instrument, the stability of the air supply system, and the appropriate pressure should be adjusted (1-1.5Pa for the thin edge, 1.5-3Pa for the thickness).
④ Properly increase the edge sealing speed to avoid the hot melt adhesive being exposed to the cold air for too long.
⑤ Check whether the back coating of the edge banding is qualified. After the edge banding is completed, put it at room temperature above 15°C, pull off the edge band, and check whether there is glue or wood chips at the bottom of the edge band. If not, it can prove the edge band The back coating is unqualified or the edge sealing hot melt adhesive is unqualified. If it is veneer edge sealing, check whether it is a resin species, or whether the wettability of the non-woven fabric on the back reaches the standard.
⑥ Check whether the board is too loose or unqualified, and whether the stacking time of the board is too long and there is too much dust on the port.
⑦According to different types of edge banding models, choose hot melt adhesives with longer "exposing time", good infiltration effect and strong penetration.
2. Slotting is easy to collapse and degumming
All thermoplastics are greatly affected by temperature, and the lower the temperature, the more prone to cold shrinkage, and hot melt adhesives and edge bands are no exception. They harden further with decreasing temperature and create internal stresses at the bonding interface. When the impact force of the slotting tool acts on the bonding interface, the internal stress is released, causing edge chipping or debonding. To deal with this problem, the temperature of the plate during grooving can be adjusted to above 18°C, so that the soft elastic hot melt adhesive can relieve the impact force of the tool; or change the direction of rotation of the tool, so that the impact force of the tool acts on the surface of the edge banding strip; or Reduce the grooving advance speed and sharpen the grooving tool to reduce the impact force of the tool.
3. There is a "drawing" situation on the edge
Generally speaking, the situation of "drawing" mainly occurs when using transparent glue to seal the edge. Especially in winter, the temperature difference between indoor temperature and outdoor temperature is large, and air convection will change the temperature environment, resulting in the occurrence of "drawing".
In addition, if the temperature is too high or too low, and the amount of glue applied is too large, there may also be a "drawing" situation. It is recommended that the furniture factory adjust the temperature according to the temperature and the condition of the machine.
According to the bonding principle of the edge band and the hot melt adhesive, the environment, the performance of the equipment, the quality of the materials used, the operation technology and the regulations, etc., the bonding quality of the edge band will be affected. Therefore, in order to obtain a good edge band effect, manufacturing For high-quality furniture, it is necessary to comprehensively consider the influence of various factors on the edge sealing process, and adjust from process equipment, material technology, and reprocessing procedures.