Defects of Melamine Resin Impregnated Paper Boards and Measures
Defects of Melamine Resin Impregnated Paper Boards and Measures,Melamine MDF defects ,Melamine Paper grading rules ,MDF melamine paper surface problems and inspection
- wooden boards warping: There are many reasons for wooden boardswarping, mainly as follows: 1. Uneven impregnation of base paper with different volatiles.
(2) Thermal pressure has no thickness regulation;
(3) The temperature difference between the upper and lower hot-pressing plates is too large, which makes the curing speed of the two sides of the wooden boards board inconsistent, and causes the board to bend towards the fast curing side.
Measures: 1. Adjust the impregnation speed of base paper and prepare impregnating resin according to requirements;
(2) Increase the thickness gauge of hot pressing to control the thickness of compression;
(3) Adjust the temperature difference between upper and lower pressure plates so that the difference does not exceed 4 degrees Celsius.
- Adhesive board of polishing board: Melamine resin is partially adhering to polishing board during curing, which causes surface cracking of adhering board.
The reasons are as follows:
The curing time is too long or the hot pressing temperature is too high.
There is no release agent in melamine resin.
(3) The quality of the polishing board declined.
The above shortcomings can be overcome by adjusting the hot pressing temperature, adding release agent when mixing, and better polishing board, such as chrome plated polishing board.
- Porous surface of wooden boards: The porous surface of wooden boardsis mainly due to insufficient resin flow at high temperature or low pressure. In addition, the surface structure of particleboard has some influence on wooden boards. Therefore, it can increase the pressure to the maximum, increase the volatile content and resin content of paper; increase the content of modifier by 0.5%. In addition, check whether impregnated paper is stored too long or improper.
- Layering and bubbling of the wooden boards, and the layering of the wooden boardsmainly include the following aspects:
Resin waterproof paraffin, oil or paraffin coating on particleboard surface;
(2) The resin content in impregnated paper is very small, and the fluidity of resin is too low, which makes the resin on the surface of particleboard insufficient; and (3) the moisture content of particleboard is too low or the volatile content of impregnated paper is too low.
The reason for cloth bubbling is that the base material is too thin or the moisture content is too high. When the press opens, the raw water vapor is generated at the wooden boards time.
- When the edge of wooden boardsis cut, the edge of wooden boardsis damaged and degraded due to the tearing of wood chips. The causes of the defects may be: the strength of the edge of the base material is not enough; the shearing strength of the surface layer of the base material is not enough, or the shape of the cutter needs to be adjusted; the sawing speed is too low or the feed speed of the board is too fast. Therefore, in addition to purchasing high-quality substrates, the cutting tools should be inspected regularly.
- The folding of impregnated paper during hot pressing: There are many reasons for the folding of impregnated paper during hot pressing. The following measures are generally taken to overcome the folding of impregnated paper:
(1) Slow down the closing speed of the press;
(2) Check whether the pressing strip of the polishing board is warped or whether the polishing board needs to be updated;
(3) Check the electrostatic device and clean or convert the power supply;