The manufacturing process for Arboron sheet
The first plastic laminates were made from phenolic resins that produce only dark colors. In the 1930’s a urea-based resin that was called melamine was developed and this produced a clear surface in the phenolic sheet. The process begins by soaking strips of Kraft paper in resin. Different grades and thicknesses can be made from Kraft paper by combining 7 to 18 layers of paper in the sheet according to its intended use. The paper also comes in different widths usually three, four or five feet. The paper is run through a bath tub of phenolic resins and then through a tub of melamine resin. Afterwards, the papers are placed in a drying chamber then cut and stacked into layers.
The layers are then loaded for final curing on a flatbed hydraulic press. The press compresses the resin-soaked papers at 1,400 psi while heating it with high temperature. Heat catalyzes a reaction on the resins while the phenol or melamine formaldehyde molecules attach to each in an alternating chain way. The resins flow together and then set while water molecules are being released during the process. After the process of thermosetting, the paper sheets that have been impregnated with melamine and phenolic thermosetting resins will be converted into one single phenolic sheet that is dry and insoluble. The phenolic sheet is manufactured in sheets but it can be cut to size and shapes based on the intended application.
After the manufacturing process for the Arboron phenolic laminate, it can be used for power distribution applications that require dielectric strength, low moisture absorption, chemical resistance and dimensional stability. Other applications include switchgear mounting boards, bus bar insulation, phase barriers, electrical enclosures and terminal strips.
Why melamine is used in Arboron phenolic sheets
Melamine formaldehyde is a thermosetting plastic that strengthens while it is subjected to heat during the preparation. Once melamine has set, it cannot be remolded or set into a different shape. Melamine helps in ensuring that the phenolic laminate is able to retain its strength and shape. Other types of thermoplastics can soften with heat and harden when cooled. Aside from its use in the Arboron phenolic sheet, melamine is also the resin used in most decorative laminates for countertops, cabinetry and kitchen counters because of its high resistance to heat and scratches. The laminated sheets are made from three layers; the bottom layer which is made from Kraft paper used in shopping bags is coated with a phenolic resin while the second layer of paper is designed with a desired pattern. The third layer is the clear sheet that is coated with melamine resin.