What is the reason for the plywood to be glued? Plywood is an important part of most furniture. Different types of panels have different physical properties. However, all plywood used in furniture faces the problem of ungluing.
Glue opening is a key factor affecting the quality of the plywood, and the plywood is an important indicator of the use of furniture. Therefore, only by understanding the specific reasons for the ungluing of the plywood can the unnecessary losses caused by this be avoided. Among them, the moisture content of the plywood, drying, adhesive, and external environment are the main reasons that affect the opening of the plywood.
First of all, the moisture content of the plywood is a key factor affecting the bond strength. Plywood, particle plywood, and MDF are all plywood that contains moisture. Freshly felled wood has a higher moisture content, while long-dried wood has a lower moisture content. Generally, the moisture content of the plywood is between 8% and 12%, which is the national standard. However, due to the difference in climate and air humidity, the moisture content of the plywood in different regions is different, so the control of the moisture content of the plywood in different regions is also different. Methods to control the moisture content of the plywood include natural drying and drying machine.
Secondly, drying is an important process in panel production. The drying process brings the plywood to standard faster and more evenly.
Third, the adhesive used in the sheet can also affect the glue release. If the bond strength is insufficient, debonding will ensue. For example, early urea-formaldehyde adhesives used a urea-formaldehyde ratio of 7:3 for environmental protection. However, later, the urea-formaldehyde ratio was changed to 3:7 to increase the bonding strength, which is why many plywood using urea-formaldehyde adhesives exceeded the formaldehyde emission standards.
Finally, the external environment will also affect the glue opening. Even if the plywood is well controlled, if they are exposed to dark and damp conditions for an extended period, unnecessary losses, including debonding, can occur. Sun exposure can cause the panels to crack, and prolonged humidity can affect the overall bond strength of the panels. Therefore, to avoid unnecessary losses caused by glue opening, it is necessary to choose suitable plywood and maintain furniture.