Defects and corresponding measures of melamine impregnated paper Lamination
The full name of melamine impregnated paper is melamine impregnated paper, also known as “melamine” paper. It is a type of plain paper or printing decorative paper that has been impregnated with amino resin (melamine formaldehyde resin and urea formaldehyde resin) and dried to a certain degree, with a certain resin content and volatile matter content. After hot pressing, it can be bonded to each other or to artificial board substrates as industrial paper!
melamine impregnated paper
Melamine impregnated paper veneers, on the other hand, have the advantages of low production materials, low energy consumption, fewer processes, and low cost, as well as beautiful appearance, certain wear resistance, heat resistance, pollution resistance, and easy cleaning. We are rapidly expanding into material professions such as office and civilian furniture, vehicle manufacturing, construction, shipbuilding, and interior decoration, and have already gained a considerable market share. Therefore, the quality requirements during the production process of melamine impregnated paper veneer panels are becoming increasingly high. Now let’s share the defects and corresponding measures of melamine impregnated paper veneer together.
- Panel warping: There are many reasons for panel warping, mainly including: ① Uneven impregnation of the original paper with different volatiles.
② Hot pressing without thickness gauge;
③ The temperature difference between the upper and lower hot pressing plates is too large, resulting in inconsistent curing speed on both sides of the veneer, causing the board to bend towards the side with faster curing.
Measures taken:
① Adjust the impregnation speed of the original paper and modulate the impregnation resin according to the requirements;
② Add a hot press thickness gauge to control the compression thickness;
③ Adjust the temperature difference between the upper and lower pressure plates to ensure that the difference does not exceed 4 degrees Celsius
- Polishing board adhesion: During curing, some of the melamine resin adheres to the polishing board, causing the surface of the veneer to crack. The reasons for this include:
① Curing time is too long or hot pressing temperature is too high;
② There is no release agent in melamine resin;
③ The quality of the polishing board has decreased.
The above defects can be overcome by adjusting the hot pressing temperature, adding a release agent during glue adjustment, and using other better polishing plates, such as chrome plated polishing plates.
- Porous surface of the veneer: The porous surface of the veneer is mainly due to insufficient resin flow under high temperature or low pressure, and the external structure of other particle boards also has a certain impact on the veneer. Therefore, increasing the pressure to a higher level can increase the volatile matter content and resin content of the added paper; Increase the content of the modifier to 0.5%, and check if the impregnated paper has been stored for too long or improperly.
- The layering and bubbling of the veneer mainly include the following aspects:
① Resin waterproof white wax, coated with oil or white wax on the surface of particle board;
② The resin content in impregnated paper is very low, and the resin flowability is too low, resulting in insufficient resin on the surface of the particleboard;
③ The moisture content of particleboard is too low or the volatile content of impregnated paper is too low.
The reason for the occurrence of blistering in the fabric is that the substrate is too thin or the moisture content is too high, which generates water vapor during the lamination time, causing blistering when the press is open.
- When the edge of the board is cut, the edge of the board is damaged and degraded due to the tearing of wood chips. The reason for the defect may be that the strength of the substrate edge is insufficient; The insufficient shear strength of the surface layer of the substrate may be due to the need to adjust the shape and sawtooth of the cutting tool, as well as the low sawing speed or the fast feed rate of the plate. Therefore, in addition to selecting high-quality substrates, it is important to regularly check the cutting tools.
- Folding of impregnated paper during hot pressing: There are many reasons for the folding of impregnated paper during hot pressing, and the following measures are generally adopted to overcome it:
① Slow down the closing speed of the press;
② Check if the clamping strip of the polishing plate is warped or if the polishing plate needs to be updated;
③ Check the static electricity equipment and clean or convert the power supply;
④ Check the weather condition of the impregnated paper in the storage room and the rigidity of the wet paper.
- Paper wrinkles immersed in a drying oven: Measures taken include:
① Relax the conflict brake on the relaxing device to reduce the tension of the paper;
② Reduce the tension of the paper between the automatic roller and the driven roller;
③ After the base paper passes through the top impregnation tank, the scraper is loosened and driven.
