Page 1

Understanding Basic Grades of Thermoset Plastic

Overview Thermoset Plastic Laminates are a durable and versatile form of plastic used in a variety of industrial applications. They are made by applying heat and pressure to prepreg/B-stage sheets consisting of resin and base materials, creating a composite that is more heat resistant than ordinary plastic and can be machined to make parts of most any shape. Thermosets come in differing grades, with each grade being more suited to specific tasks than others.

Basic Grades of Thermoset Plastics Canvas Base Phenolic Linen Base Phenolic

Paper Base Phenolic Glass Base Epoxy Glass Base Silicone Glass Base Melamine Glass Base Polyester

Canvas Phenolic • Canvas Phenolic comes in grades C and CE. • Grade C is appropriate for applications requiring high impact strength such as components of gears and pulleys. • Grade CE is more resistant to moisture and may also be used for electrical insulation applications.

Linen Phenolic • Linen Phenolic comes in grades L and LE. • Grade L is appropriate for mechanical and machining applications. • Grade LE provides improved moisture resistance and is well-suited for finemachining and some electrical insulation applications.

Paper Phenolic • Paper Phenolic comes in grades X and XX. • Grade X is appropriate for mechanical applications where moisture is of small concern. It typically comes in sheet form. • Grade XX provides better moisture resistance and is better suited for insulation applications. It is available in sheet, rod, tube and panel form. • An XXX grade offering even better moisture resistance is available.

Glass Epoxy • Glass Epoxy comes in grades FR4/G10, G10, FR5/G11 and G11. • FR4/G10 is strong, water resistant and is flame retardant. • G10 has the same properties, but contains no halogens for flame resistance. • FR5/G11 is even more resistant to high temperatures than FR4/G10 and is flame retardant. • G11 is similar to FR5/G11, but contains no halogens for flame resisitance.

Glass Silicone • Glass silicone comes in grade G7. • This grade offers the best heat resistance. • G7 comes in sheet, tube and sheet rod form.

Glass Melamine • Glass silicone comes in grades G9 and G5. • These grades are highly resistant to electrical arcing. • G9 is the more moisture resistant variety.

Glass Polyester • Glass polyester comes in grade GPO-1 and GPO-3. • This is a good general purpose grade of thermoset. • Typically available in sheet form only. • GPO-3 is fire retardant. GPO-1 is not.

About Accurate Plastics Accurate Plastics sells thermoset plastic products on six continents and has a reputation for exceptional products and customer service. In business for 30 years, our firm is an ISO 9001 certified company. Accurate Plastics will work with you to determine how thermoset laminates can benefit your products and provide you with reliable, quality plastic. To learn more, visit

Understanding Basic Grades of Thermoset Plastic | Thermoset plastic is a strong, fire-resistant form of plastic with many industrial applications. Differing grades o...