Melamine impregnated paper,use high quality printed decor paper, impregnated with melamine resin, then laminated onto all kinds of wood based panels. It plays a very good decorative effect on the surface of panels, and make the surface resistant to high temperature, wear-resistant and anti pollution.
At present the impregnation usually adopts the twice saturation. The decor paper is firstly impregnated with normal melamine resin to get the core layer, then use high quality melamine resin for second impregnation.The melamine resin in these two times impregnation can be adjusted as per requirements to ensure the final quality of melamine impregnated paper, and to make the production economical. Impregnation has strict requirements on printed decor paper and melamine resin. The resin after modulation should obtain the flexibility, which can prevent the surface brittle crack. In actual production, melamine resin also need to add a variety of additives.
In order to guarantee the quality of the melamine impregnated paper, high quality decorative paper must be used. Decorative paper has no α pulp fiber,performs well in color fade, and be resistant of high temperature of 180 C, and of good opacity. In normal the grammage of decor paper should be 70-90g/㎡, with tolerance of ± 2g/㎡, the moisture content 2.5-4.2%, PH value 6.5-7.5. If the PH value is too low, it may wrinkles during impregnation. To avoid break during impregnation, the length of the longitudinal wet break is at least 450m, and the lateral 300m. To obtain a good impregnation speed, decor paper should have very high absorbent with quick penetration. Water suction height requirements: vertical 25-35mm/min, horizontal 22-30mm/min. Smoothness of decor paper should be moderate, too low may affect the lamination effect on surface and too high will reduce the ability of impregnating resin.
Modulation resin is mainly MF and UF, as well as a variety of additives. Curing additive plays the role of catalyst to accelerate curing time during lamination. Wetting additive is to reduce the surface tension of resin,and enhance the penetration ability on decorative paper to confirm the impregnation uniformity. Release additive is used to prevent impregnated paper from steel plate during lamination.Defoaming additive is used to avoid bubbles in resin bath which may affect impregnating uniformity. Solvent is water or ethanol, diluted to adjust the viscosity to obtain good permeability on decor paper. Using special glue technology to make melamine formaldehyde resin and urea formaldehyde resin, and then add the modifier and storage, finally add a hardening additive, wetting additive, release additive, foaming additive and other additives,inject into resin bath. After twice impregnation,decorative paper need to be dried, cooled and cut into certain sizes. The size requires to be about 10-30mm bigger than panels in width and length.In the impregnation process, we should follow the strict requirements of the process operation, test samples every 30 min, guarantee resin content of 130-150%, volatile matter content 6-7%, pre-curing degree ≦ 65%. With approval, the finished melamine impregnated paper sheets could be packed sealed by polyethylene film. About 200 sheets per bale, 10 bales each pallet. In order to ensure the quality lamination, melamine impregnated paper should be stored in good condition. The relative humidity in the warehouse is 60±5%, so that the paper will not absorb or release moisture. Temperature should be 20-25℃. High temperature and high humidity make the impregnated paper sheets becomes soft and sticky. But impregnated paper is easy to break when the temperature is too low. The shelf life of impregnated paper is about 3 months if they are stored well. To prevent sticky because of moisture absorption, please repack and seal well once opened.
The resin content (solid resin relative to the weight of the resin) is 130-150%. The low resin content brings low strength on paper, and it is easy to dimex. The proper melamine content is good for lamination in production and quality. When the resin content is too high, it is easy to crack. The content of volatile matter (at 160℃ drying for 10 minutes) was 6-7%.