PAWTUCKET, RI, U.S.A. -- Teknor Apex Company
has announced that a new styrene block copolymer thermoplastic elastomer (TPE-S)
for automotive interior parts
such as cable ducts and grommets exhibits improved injection moldability compared with other elastomers while providing competitive physical properties and meeting stringent OEM requirements.
Sarlink® ML-2355B for Cable Ducts
Sarlink® ML-2355B TPE-S compound has been approved by VAG for cable ducts. Used to guide cables in their convoluted route through the spaces in pillars and other structures surrounding the passenger compartment, these ducts are complex parts with long flow paths and many undercuts, making them a challenge to mold and de-mold.
- Compared with other elastomers used for cable ducts, new Sarlink ML-2355B TPE-S exhibits reduced viscosity for improved moldability, a wider processing window, and greater weld-line strength to facilitate air-assist de-molding.
- Unlike standard TPE-S compounds, it does not exhibit stress marks caused by deformation during mold release, and it avoids the de-molding difficulties posed by thermoplastic vulcanizates (TPVs) in parts with severe undercuts.
Jeffrey E. Dickerhoof, Senior Sales and Marketing Manager for the Thermoplastic Elastomer Division of Teknor Apex, said:
“The enhanced processability of Sarlink ML-2355B compound provides better surface quality than standard TPE-S materials and fewer sink marks, which exhibiting lower processing temperatures, faster cavity filling, and improved mold release”.
Advantages of Sarlink ML-2355B TPE-S Over Standard Rubber
Sarlink ML-2355B TPE-S also provides numerous advantages over thermoset EPDM rubber, starting with a lower density that translates into 20% weight savings, plus the benefit—as a thermoplastic—of scrap recycling.
Ger L. Vroomen, Senior Automotive Market Manager for Teknor Apex, said:
“Processing improvements versus EPDM include shorter cycle times, easier processing of complex geometries, adhesion to polypropylene (PP) through two-component molding, and capability for robot-assisted de-molding, which is impossible with EDPM. Sarlink ML-2355B compound also remains elastic over a broader temperature range and provides improved flex fatigue behavior.”
Typical Properties of Injection Molding Elastomers for Automotive Interior Parts
Source: Teknor Apex
OEM part requirements for the VAG cable duct include:
- an operational temperature range of -40 to 90 °C;
- burning behavior meeting the TL-1010 flammability standard for passenger compartments;
- electrical insulation meeting specification PV 1015;
- a water-tight seal;
- passage of natural weathering tests for one year in both hot and humid and desert-dry conditions.
Minimum OEM material requirements for the application include odor and emissions, tensile strength and elongation, property retention after 90 °C / 94 hrs heat aging, and avoidance of cracks or surface changes after 150 °C / 700 hrs heat aging.
Sarlink ML-2355B TPE-S is a black 55 Shore A compound; other hardnesses are available. Teknor Apex can supply the compound worldwide.
About Teknor Apex
Teknor Apex Company, a privately held firm founded in 1924, is one of the world’s leading custom compounders of plastics. Teknor Apex produces flexible and rigid vinyl, thermoplastic elastomers, nylons, color masterbatches, specialty chemicals, and hoses. The company is headquartered in Pawtucket, RI, U.S.A. and operates thirteen manufacturing facilities worldwide in the United States, Belgium, Germany, China, and Singapore.
The Thermoplastic Elastomer Division of Teknor Apex Company offers the broadest portfolio of TPE compounds available from a single source. The division compounds TPEs at eight locations in the U.S., Europe, and Asia under the brands: Elexar® (electrical and electronics applications), Medalist® (medical devices), Monprene® (consumer and industrial products), and Sarlink® (transportation).
Source: Teknor Apex Company