TPEs have been used for over 10 years in automotive sealing, and are now recognized as a direct alternative to EPDM rubber. CTS believes that by 2020 they will represent 25% of the automotive sealing market, offering a growth rate double the global vehicle growth rate.
Fixed glass encapsulation and fixed seals were the first applications for TPEs, before the industry began looking at semi-dynamic seals such as belt line seals and glass run channels, which are increasingly being made from TPE. Research is now being conducted on door seals, whose dynamic function increases the difficulty.
TPEs offer weight savings, increased productivity, lower investment and recycling, which puts them well ahead of EPDM in the area of sustainable development.
With specific gravity roughly 30% lower than that of vulcanized EPDM and the ability to replace steel reinforcements with polypropylene (filed or not), TPEs help reduce vehicle weight.
Moreover, the absence of vulcanization during extrusion reduces cost and makes the process more energy efficient. This makes it easier to design small production units similar to assembly lines, greatly reducing the complexity of the supply chain and giving more flexibility while minimizing the carbon footprint.
A sealing system has several functions.
There are the functional parts, which consist of one or more sealing lips whose geometry should be tailored to the properties of the material.
Then there is the anchoring of the profile to the body of the vehicle. Although it remains invisible, this part requires good mechanical properties, particularly a high flexural modulus.
Finally, the bond between the extruded profiles (corners in particular) is completed by injection molding with a TPE formulated by CTS with a sliding function, which eliminates the extra process step of flocking the molded corner.
When comparing technology all applicable advantages must be explored. Seal discoloration and harmony over time is a widespread problem of EPDM. TPVs partially correct this, but do not reach the level expected by manufacturers. However, resistance over time is a key feature of TPE-S and TPE-SV such as Téfabloc ™.
The wide variety of surface finishes available also distinguishes TEFABLOC™ (TPE-S- TPE SV) from other TPEs, and in particular TPVs made from EPDM. TEFABLOC™ comes in various finishes and colour-matching is available, thus meeting the expectations of manufacturers in terms of aesthetics.
This is perfectly illustrated through three examples of vehicles for which TEFABLOC ™ offers a specific solution: The C3 Picasso, which has matte finish seals, the Fiat Giulietta which has seals with a semi-gloss finish, and the Suzuki Splash, which has glossy seals. To meet these needs CTS offers TPE-S and TPE-SV on a gloss scale from 1-20.
This gloss range is available for extruded parts (glass run channels) and injection moulded parts (corners, belt line seals, fixed window encapsulation) and the TEFABLOC™ range is available for these different processes to obtain perfect consistency in terms colour, gloss and aging.
Seals can now do much more than provide a sealing function. TEFABLOC™ TPE-S with or without crosslinking makes seals an integral part of the design, providing new opportunities for automotive sealing suppliers. For instance, the seals of vehicles under development will be proudly displayed on the car body as a true design component.
And tomorrow? CTS is working actively to finalize the development of formulas that will meet the future requirements of the automotive industry in terms of sustainable development, namely to replace non-recyclable materials and provide materials that contain a significant portion of reclaimed or renewable materials. The progress of research in this area means that we will likely be marketing solutions containing a high percentage of green materials by the end of 2010.
TEFABLOC ™ is a registered trademark of CTS and the TPE-S (TPE-SV) crosslinking process is patented.
More information about CTS - Compound Technology Services available on www.cts-compound.com
CTS: the expertise in Automotive
CTS has designed and produced thermoplastic materials for nearly 50 years. They are used for numerous applications. And in all sectors they have been unmistakably successful.
As a pioneer in TPEs, CTS has always played a leading role in developing soft thermoplastic materials matching the technical requirements and the strong design expectations required in automotive applications.
This offensive strategy has lead CTS to:
- rank N°1 in Europe and 3rd worldwide for airbag covers
- be the first supplier of TPE-S being used for automotive glass run channels.
- be the first supplier of TPE for thermoplastic steering wheel manufacturing
- to make Marvyflo® the material used to produce the dash board skin for 1 in every 4 cars in Europe.
CTS is part of the Tessenderlo group, an international company active in many areas of the chemical industry.
To get more information, please visit www.cts-compound.com , www.tessenderlogroup.com.