Rigid Laminate Material Summary
Thermoset Rigid Laminates
There are two primary types of thermoset laminate materials: high pressure and low pressure.
High pressure laminates are manufactured by laminating multiple layers of B-stage substrate in a press under heat and pressure. Typically, several sheets of material can be made in one press. Cure times vary according to material, but a press load of material may take anywhere from 2 to 4 hours to cure.
Low pressure laminates are manufactured by laying random glass mat material into a mold. Then, the mold is filled with polyester resin. The press then cures the sheet of material under heat and pressure. Low pressure laminates are produced one sheet at a time with relatively short curing times ranging from minutes up to an hour.
Typically, high pressure laminates offer much better mechanical properties due to the inherent structure of a woven substrate versus a random mat material. In addition, the longer curing times at higher pressures helps produce a stronger laminate. However, low pressure laminates are typically less expensive due to their shorter manufacturing times.
The following list of high and low pressure laminates represents an overview of the materials available for use as components depending on the unique characteristics of the equipment application. Of course, as with any engineering design decision, there are many alternatives depending on the application specifications. Our staff can help determine the best possible options for the material to satisfy application requirements.
High Pressure Laminates
High pressure laminates are composite materials made from a base or substrate material impregnated with a particular resin system. The combination of substrate and resin system provide each laminate material with a specific set of properties. Due to the high pressure lamination process, these materials typically have very high mechanical strength characteristics. As thermoset plastics, they also exhibit outstanding temperature resistance properties maintaining their mechanical properties at elevated temperatures.
| Material Description, Grade | Temp Class | General Description | Common Applications |
|---|---|---|---|
| Canvas Phenolic, NEMA CE | 130 C | General purpose laminate primarily used for mechanical applications requiring basic dielectric properties. | Bearing housings, motor and generator wedges, wear plates, gears, and trunnions. |
| Linen Phenolic, NEMA LE | 130 C | Fine weave cotton cloth laminate primarily used for mechanical applications requiring improved machining properties. | Gears, trunnions, terminal strips, and various punched parts. |
| Paper Phenolic, NEMA X, XX, & XXX | 130 C | Kraft paper based laminate primarily used in transformer applications requiring excellent dielectric properties with good oil compatibility. | Tap changer boards, terminal strips, fuse boards, phase barriers, lead clamps, and conduit tubes. |
| Arboron Paper Phenolic Laminate | 105 C | General purpose paper phenolic laminate with arc resistant melamine surface. | Fuse support boards, terminal strips, transformer coil supports. |
| Glass Melamine, NEMA G-5 & G-9 | 130 C | Glass cloth based laminate with excellent dielectric and arc resistance properties. Very good mechanical strength. | Motor topsticks and wedges, switchgear terminal boards, and fuse insulators. |
| Glass Silicone, NEMA G-7 | 220 C | High temperature glass cloth laminate with excellent dielectric and arc resistance properties at elevated temperatures. | Electric furnace insulation components, circuit breaker arc chutes, bus tube clamps. |
| Glass Epoxy, NEMA G-10 | 130 C | General purpose glass cloth based laminate with excellent mechanical strength and good electrical properties. Not flame retardant and thus, a non-brominated material. | Motor and generator wedges, transformer coil supports, terminal boards. Material for non-brominated requirements. |
| Glass Epoxy, NEMA FR4 | 130 C | General purpose glass cloth based laminate with excellent mechanical strength and good electrical properties. Most commonly a brominated flame retardant resin system. | Motor and generator wedges, transformer coil supports, terminal boards. Contains brominated flame retardants in most grades so care should be taken in using this material. |
| Glass Epoxy, NEMA G-11 | 180 C | High temperature version glass cloth based laminate with temperature resistance up to 180C. Excellent mechanical strength. | Motor and generator wedges, dry type transformer terminal boards. |
| Silicone Bonded Mica Laminate | 500 C | Highest temperature thermoset laminate with very good mechanical and electrical properties. | Electric furnace insulation, high temperature appliance components, arc chutes. |
| Epoxy Bonded Mica Laminate | 180 C | General purpose mica base laminate with excellent electrical properties. Limited mechanical strength versus glass laminates. | Resistor insulators, fuse element supports, dry type transformer insulation. |
Low Pressure Laminates
Low pressure laminates are composite materials made from a base or substrate material that is typically a random mat glass. The random mat glass is impregnated with a particular resin system, typically in the polyester resin family. The combination of glass mat substrate and the particular resin system provide each laminate material with a specific set of properties. To review a complete data sheet for a material, click on the material grade.
| Material Description, Grade | Temp Class | General Description | Common Applications |
|---|---|---|---|
| Glass Polyester, NEMA Grades GPO-1, GPO-2, & GPO-3 | 130 C - 155 C | GPO-1 grades are general purpose grades with good mechanical strength and good electrical properties. GPO-2 and GPO-3 grades offer improved electrical properties and flame retardance characteristics. | Bus bar supports, bus duct windows, phase barriers, fuse boards, terminal strips. |
| Glass Polyester Angles & Channels | 130 C | Wide range of standard angles and channels for structural applications. | Bus bar supports, structural members, fuse supports. |
| Stand-off Insulators | 130 C | Complete line of stand-off insulators. | Bus bar supports, coil supports, and fuse supports. |
| Pultruded Rod, Dogbones, and Specialty Shapes | 155 C - 220C | Wide range of standard pultruded shapes. | Coil spacers, terminal strips, and supports. |
| Glass Polyester Grades SG-200 & HST-II, & N220 | 220 C | High temperature grades with good mechanical properties at elevated temperatures and excellent dielectric properties. | Transformer winding combs, coil supports, phase barriers. |
| Glass Polyester Grade LST | 130 C | Specialty U.V. resistant grade of NEMA GPO-3 for outdoor applications. | Outdoor bus supports, phase barriers, and bus duct windows. |
| Glass Polyester Grades Glastherm S & HT, Thermalate, & Grade MPI |
250 C | High temperature boards designed for mold platen insulation applications. | Mold platen thermal insulation. |
