Minimum Friction Maximum Performance

For years, professional athletes have been coating their ski and snowboard gear with ultrathin coatings that provide exceptional glide properties. Surface coatings at nano-scale are not only for winter sports anymore. Seal-Glide®, an innovative surface treatment from Trelleborg Sealing Solutions, significantly improves friction and stickslip properties of elastomer seals while having little or no effect on the performance of the compounds the seals are made from.

-By Donna Guinivan

IN SHORT

  • The Seal-Glide® process allows seals to be coated thinly to just a few hundred nanometers.
  • Two versions are available; Seal-Glide® Nano for general applications and Seal-Glide® Medical for healthcare applications.
  • Advantages of the coating includes low friction and enhancing automated processes.

Seals coated with Seal-Glide® improve feed rate in automatic assembly lines

Seals coated with Seal-Glide® improve feed rate in automatic assembly lines

THE SEAL-GLIDE® RANGE

Currently there are two coatings in the Seal-Glide® range:
Seal-Glide® Nano for general applications.
Seal-Glide® Medical for healthcare applications.

Further coatings will be added in the future

THE UNIQUE SEAL-GLIDE® PROCESS ALLOWS SEALS TO BE COATED THINLY to just a few hundred nanometers, ten to 50 times less than typical coating thicknesses. Despite the thinness of the coating, it significantly reduces the friction coefficient of elastomer seals and improves their stick-slip properties considerably.

Seal-Glide® is suited for coating classic O-Rings and complex molded parts for a wide range of applications and is available in two versions: Seal-Glide® Nano for automotive and industrial uses and Seal-Glide® Medical.

Resistant to sterilization processes

“The Seal-Glide® Medical coating is ideal for use in healthcare and medical applications as the new process has a very high level of stability,” says Andreas Schmiedel, Technical Manager for Healthcare and Medical in Europe at Trelleborg Sealing Solutions. “This makes it resistant against sterilization with gamma radiation, ethylene oxide and hot steam, which is essential for the multiple use of medical devices, fermenters or syringes.

“To this end, the coating process satisfies the strict requirements for medical, bio-technology and pharmaceutical applications as prescribed by the authorities such as the American FDA (Food and Drug Administration) or European standards such as DIN EN ISO 10993 for the biological evaluation of medical devices.”

“The Seal-Glide® Medical coating is ideal for use in healthcare and medical applications as the new process has a very high level of stability.”

-ANDREAS SCHMIEDEL, Technical Manager for Healthcare and Medical in Europe at Trelleborg Sealing Solutions

SUITABLE MATERIALS

Seal-Glide® is suitable for many types of elastomer and thermoplastic seal material types. These include LSR (Liquid Silicone Rubber), Ethylene Propylene Diene Monomer Rubber (EPDM), Fluorocarbon (FKM), Fluorosilicone (FVMQ), Nitrile Butadine rubber (NBR), Hydrogenated Nitrile Butadiene Rubber (HNBR), Ethylene Acrylate Rubber (AEM), and silicone rubber (VMQ) as well as thermoplastic polyurethane (TPU).

High volume automation

In automotive or industrial applications, Seal-Glide® Nano gives distinct advantages in high volume automated assembly lines.

“The strong surface tackiness of elastomer seals is an inherent property, which can cause issues such as the creation of high assembly forces, disruptions in automatic assembly lines as well as reduced performance in dynamic applications,” says Gordon Micallef, Operations Director at Trelleborg Sealing Solutions in Malta, where Seal-Glide® Nano was developed.

“On many assembly lines, overall speed is limited by the elastomer parts feed rate. Due to the reduction in coefficient of friction, the use of the Seal-Glide® Nano coating will result in significant efficiency gains, by considerably improving the feed rate in automatic assembly lines. This is also important in healthcare and medical applications.

“When coated, O-Rings or complex molded parts can be installed more easily and securely in components due to better separation of the seals,” continues Andreas. “Using the friction-reducing coating, the components can be assembled smoothly and without damage so that the entire assembly process is completed simply and securely. Feed issues are minimized, reducing the probability of production stops.”

“Another advantage of Seal-Glide® is that due to its thinness, the coating has a high level of transparency and does not cover the original color of the elastomer.”

-GORDON MICALLEF, Operations Director at Trelleborg Sealing Solutions in Malta

Same properties, longer life

Typically Seal-Glide® coatings are less than 450 nanometers. It therefore imparts the benefits of a surface coating, without affecting the bulk properties of the seals. As a result, the original elastic properties of the elastomers are virtually unaltered but the seals have a higher service life due to reduced wear when in motion or on start-up.

“Another advantage of Seal-Glide® is that due to its thinness, the coating has a high level of transparency and does not cover the original color of the elastomer,” says Gordon. “The color of seals can play a central role in assembly. O-Rings are mostly black, but are often dyed in order to visually highlight differences in composition, diameter, thickness or positioning within a component.

With our innovative coating, this color coding is retained, even after the coating.” “All in all, the Seal-Glide® coating may be thin, but it can give big advantages to our customers,” concludes Andreas.

STICKY SEALS Elastomers without a surface treatment tend to stick, either to each other during automatic assembly or to counter surfaces in dynamic use.

MINIMIZING STICK-SLIP A particular issue is after periods of rest, when due to an elastomer’s inherent stickiness, there can be a stick-slip-effect. In this, the elastomer seal sticks to its counterpart and when moved elastomer is pulled off the seal reducing seal life. In addition, extra energy is required to move the seal from a stationary position.

This stick-slip effect can be minimized or even virtually eradicated through effective surface treatment of a seal.