Characteristics | Plenco's Commitment | Typical Applications for Phenolic Molding Materials

Plastics Engineering Company manufactures a full range of phenolic molding materials. Plenco thermoset compounds are suitable for evaluation in industrial and consumer applications, which require molded properties to be maximized, but unit cost to be minimized. Plenco phenolic two-stage, single-stage, and pigmented molding materials are produced in granular, nodular, and briquette forms.

Plenco thermoset phenolic molding material is manufactured with state-of-the-art process control and quality management systems to ensure the highest product quality and uniformity. At a relatively low unit cost, Plenco phenolic molding materials offer outstanding long-term engineering performance when exposed, under load, to elevated temperature. Additionally phenolic materials have excellent chemical resistance, electrical insulation, surface hardness, and dimensional stability.

In the design of Plenco phenolic molding materials, specific base-resin properties, filler composition, lubricants, and moisture content are important to a particular application. Key formulation properties, such as plasticity, extent of flow, and particle size help to ensure cost-effective and highly productive molding. All of this offers Plenco customers an optimized combination of characteristics, which are available for knowledgeable material selection.

Formulations are typically engineered with two-stage phenolic resins for a broad range of molded properties and processing latitude. Single-stage phenolic resins contribute to long-term service in those applications requiring moisture and steam exposure, and minimum corrosion. When the end product calls for bright and stable computer-matched color, Plenco offers a unique line of melamine-phenolic copolymer molding materials.



Thermal Performance

It is often recognized in the evaluation of available plastics for a given application that the outstanding characteristic of cured thermoset phenolic molding material is excellent thermal performance. This is especially significant when consideration is given to the relatively low unit cost of these materials.

Thermal performance refers to the ability of a molded plastic product to maintain its structural integrity, under mechanical load during a prolonged exposure to elevated temperatures. The thermal performance of polymer systems is closely related to their glass transition temperature (Tg). This is the temperature at which the molecules rapidly gain in their mobility as the cured molded sample is heated. Even in the presence of fillers and reinforcements that provide the apparent initial rigidity, exposure to temperatures above the Tg will usually cause a polymer to flow or creep under load.

Engineered Creep Resistance

The relatively high glass transition temperature of cross-linked polymers, such as phenolic, results in excellent resistance to creep under mechanical load. A unique property of cured phenolic is the ability to raise its Tg by a carefully controlled post bake protocol, after the part is molded. When correctly applied, the post bake program can result in a further improvement in creep resistance, dimensional stability, and modulus (stiffness) at elevated temperature.

Dynamic Mechanical Properties

Dynamic mechanical analysis (DMA) is a powerful analytical tool for characterizing the thermal properties of polymers. The important feature of DMA is that the physical measurements of storage and loss modulus are made so gently that the sample is not damaged. It is therefore possible to observe the changes in modulus as a third parameter, such as temperature, is varied. With this and other analytical techniques, Plenco chemists and engineers, who have achieved a considerable understanding of the post bake process, are available to assist in the optimization of dynamic mechanical properties and thermal performance of your cured phenolic parts. Reports on post baking and its effect on the glass transition temperature that are published by Plenco are available upon request.

Heat Resistance

Because of excellent thermal performance, phenolic molding materials are specified to insulate and protect sensitive components from the adverse effect of high temperature exposure. Plenco manufactures a wide range of phenolic molding materials designed for high temperature use. These grades are formulated with resole or novolac resin systems, and specially selected fillers and reinforcements, in order to meet end use specifications. Consumer safety is enhanced when the potential for the end product to overheat, melt or initiate a fire is minimized through the selective use of a heat resistant phenolic molding material. Plenco heat resistant phenolic grades are the materials of choice for automotive under-the-hood parts, cookware handles and knobs, and electrical appliance components.

Underwriters Laboratories Ratings

Phenolic molding materials are listed by Underwriters Laboratories with a generic Relative Thermal Index of 150� C. this listing is based on the excellent 75-year safety record of molded thermoset phenolic components used in electrical and consumer products. Especially noteworthy is Plenco 06582, a modified phenolic formulation, which is UL yellow card listed at 180� C.

Careful formulation of Plenco phenolic molding materials makes them ideal candidates in applications requiring optimum flammability characteristics. Unlike many thermoplastic resins, phenolic molded parts, when exposed to an ignition source, do not drip flaming particles, a potential ignition source. Plenco phenolic molding materials are tested and classified according to the UL 94 Flammability Standard as HB, V-1, or V-0. Typical applications specifying these ratings include appliance components, electrical distribution products, and housewares applications.

Dimensional Stability

Many of Plenco's phenolic molding materials are formulated to provide tight dimensions with minimal deformation under mechanical load at elevated temperatures. This characteristic is critical when considering calibration requirements, screw-torque retention, and dimensional specifications to prevent thermal, mechanical, or electrical failure, especially during thermal cycling of end used products. For this reason, power train components, electrical motor housings, brush cards, control housings, and telecommunication connectors specify phenolic formulations.


Plastics Engineering Company offers several unique phenolic molding materials enhanced with graphite, PTFE, and other internal lubricants. These formulations provide excellent lubricity and abrasion resistance for components that require repeated mechanical cycling or part-to-part contact. A key advantage of components molded from these materials is their ability to maintain surface smoothness after mechanical lapping. Plenco self-lubricating phenolic materials are used in gas metering devices, fuel impellers, toggle switches, seals, and bearings.

Plenco's Commitment

Plenco's accredited Resin Research and Materials Engineering Laboratories, extensive resin manufacturing and compounding facilities, and ongoing technical sales efforts are direct indications of a strong dedication to building strategic relationships with our customers. Plenco has the capacity to deliver large quantities of consistent and high quality thermoset molding materials that meet or exceed customer specifications. Additionally, we have a philosophy of continual product improvement and cost containment. All of this is supported with in-depth engineering suggestions for tooling and part design, and assistances with prototype molding. And finally, there is Plenco's responsive distribution center offering custom handling and efficient, on-time delivery, often in Plenco's own fleet of trucks.

The combined effort of materials engineering and manufacturing at Plenco, along with good communication with our customers, is key in developing value-added end-product characteristics. While many of Plenco's formulations are suitable for evaluation in typical applications, often our molding materials are the result of customized development and engineering to match specific molding situations or end-use requirements of individual customers. This results in a wide range of phenolic formulations and plasticity grades. We look forward to working with you to explore the application of Plenco phenolic molding materials in your process or product application. Detailed data reports and price schedules are available upon request.

After the engineering and development program is completed and the tooling is in place, Plenco will provide an experienced group of technical service personnel, who offer out customers assistance in processing initial samples for their fitness-for-use testing, or in solving problems in production processing. We will do our best to help out immediately by phone or fax, or if you wish we will come to your plant promptly. Our strong commitment to polymer science research, together with the design of innovative molding materials, proves Plenco to be a leader in the thermoset phenolic industry.

Typical Applications for Phenolic Molding Materials

  • Cookware handles and knobs
  • Electrical terminal strips
  • Drive train components, brake components, engine oil fill caps, and motor and alternator components
  • Small appliance parts, such as steam iron skirts, range strips, appliance plug parts, houseware items, and popcorn popper chutes
  • Gas meter parts
  • Bottle and container covers and closures
  • Electrical applications, such as switch housings, circuit breaker cases, fuse holders,
    lighting baffles, snap-switch housings, capacitor caps, connectors, and commutators
  • Parts for automotive interiors



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