3 Key Steps to Designing for the Unique Demands of Appliances

IDSA Ambassador Teknor Apex Shares INsights on TPE Materials for White Goods

Dec 22 2016 - 12:41pm

IDSA Ambassador Teknor Apex weighs in with its latest installment for IDSA’s INsights.

Manufacturers of major appliances and their components know the value of thermoplastic elastomers (TPEs) which provide rubber-like elasticity, without the design and processing limitations of rubber, and offer performance advantages over flexible PVC. But until recently, their choice of TPE materials was limited to general-purpose thermoplastic vulcanizates (TPVs)—originally formulated for automotive seals and gaskets.

General-purpose TPVs work—but appliances have special demands: custom color and palette matching requirements, resistance to household chemicals and, in some cases, FDA-compliant ingredients for food safety. Designers of white goods with elastomeric components—such as seals, gaskets, hoses, O-rings, motor mounts, drain tubes, shock absorbers and feet—no longer have to rely on a few general purpose TPV compounds. Continuous innovation in material development has led to new, specialty TPEs that are formulated for the particular rigors of specific appliances including:

• Improved copper-resistant TPV for dishwashers

• High heat-resistant TPV (135°C versus 120°C) for dryer components

• Colorable TPEs (also available pre-colored)

• Food contact TPEs for kitchen appliances

IDSA Ambassador Teknor Apex explores how these innovative performance capabilities open new opportunities to design components for white goods—and deliver competitive advantages to workhorse appliances. The categorical advantages of TPVs include thermoset rubber materials such as EPDM, which traditionally are used in appliance components requiring resistance to deformation, heat and chemicals—while flexible PVC is used in less-stringent applications where aesthetics and cost are the primary considerations. Thermoplastic elastomers, such as styrenic-based TPEs and TPVs, offer more design flexibility and a better balance of price and performance than both EPDM and PVC.

Currently using rubber? Replacing traditional EPDM seals with TPV seals results in an overall cost reduction and improved sealing, with:

• Improved long-term performance: TPVs have better aging properties than EPDM and maintain their physical properties better over the life of the appliance

• More design freedom: TPVs can be co-extruded into a seal, or over-molded onto PP for an air-tight gasket; using a more cost-effective process (part consolidation, less assembly) resulting in better functionality

• Reduced environmental impact: TPVs are lighter weight (reduced shipping costs) and are recyclable; resulting in less scrap

Currently using flexible PVC? Compared to flexible PVC, styrenic-based TPEs:

• Remain more flexible at low temperatures and are less susceptible to deformation or cracking

• Can be over-molded and co-extruded over polypropylene (PP) for better sealing performance

• Are lighter weight (Specific Gravity = 0.89 versus 1.2)

• Offer better compression set or higher resistance to deformation due to rubber-like characteristics

• Are less prone to fungal growth like mold

• Can be customized for a matte, rubber-like finish

Teknor Apex hones in on three key steps:

  1. Define Application Requirements: In selecting a TPE compound for appliance components, designers encounter a range of considerations that vary with each application, such as basic performances requirements; end-use conditions; and regulatory concerns.
  2. Understand Material Options for White Goods: New specialty grades of TPVs solve challenges posed by high heat or corrosive chemicals, while new styrenic provide alternatives to TPVs in applications requiring special appearance characteristics or FDA compliance. The portfolio of specialty TPE and TPV offerings continually is expanding to meet design applications and requirements for specific appliances such as washing machines, dryers, dishwashers, refrigerators and freezers.
  3. When Needed, Rely on Custom-Formulated TPEs Collaborations: Component designers truly have unlimited new material options that raise the bar on performance, safety and regulatory compliance, aesthetics and longevity. Today’s innovation is introducing new combinations of critical performance attributes for white goods components. There are thousands of ways to formulate TPEs. These materials are as versatile as they are useful. As a true partner of designers, Teknor Apex provides technical support that draws on the resources of its material libraries and application development laboratory to offer local engineering assistance, including advice on materials, tooling and processing.

The full ebook is available here for download.

Questions? Email tpe@teknorapex.com; call 401.725.8000; or go to www.teknorapex.com. Read more about IDSA Ambassadors.