Treatment designed to improve the performance of O-rings
Standard elastomer O-rings sometimes need to undergo special surface treatment. This will enhance the performance of the equipment and levels of productivity in the assembly and mounting processes in which these seals are used.
We at JIOrings treat the surface of O-rings using special cleaning, immersion or coating processes, with the aim of reducing friction and adhesion in order to achieve a permanent lubricating effect and to facilitate the installation of the seals.
This treatment is usually carried out on large quantities or batches, however, if you have any such needs, we recommend you contact us to enable us to analyse your request and propose the appropriate solution. We provide the following different types of treatment and surface coatings:
- Coloured PTFE
- Micro Talc
*Requesting and downloading the technical data sheets for each type of treatment is subject to the purchase of seals subjected to any of the aforementioned coatings.
PTFE (polytetrafluoroethylene) coating, also known as TEFLON® (the registered trademark of Chemours), is a fluoropolymer-based coating designed to provide excellent anti-adherence to the seals.
PTFE is a material that is suitable for contact with food (FDA), and as such is used in many industrial sectors such as food, beverages, chemicals, textiles… The process for coating seals with PTFE Teflon® consists of four different stages:
- Degreasing – Consists of the removal of any organic or inorganic residue on the parts. The seals to be treated need to be degreased to do this.
- Sandblasting – The preparation of the surface to be coated in order to guarantee the maximum adherence of Teflon® by sandblasting with aluminum oxide.
- Application – This is conducted using liquid, electrostatic, HVLP spray guns or powder guns. The process can consist of several layers of product, depending on the purpose of the coating.
- Curing – The coating needs to be polymerised to ensure Teflon® retains all its properties. This involves keeping the seals at a temperature of 360 ºC for 10 minutes.
A silicone coating provides seals with greater anti-adherence, impermeability and mechanical resistance. In addition, silicone seals have better sealing and thermal insulation. A silicone seal has the following advantages:
- Greater thermal resistance.
- Good flammability properties.
- Excellent impermeability (even in hostile conditions: weather, water, steam, smoke and combustion gases).
- Excellent flexibility.
- Easy to clean.
- Greater durability.
Molykote is the trade name for special Dow Corning lubricants. This lubricant is designed to deal with industrial lubrication issues and to reduce friction and wear.
Treating O-rings with Molykote, which features molybdenum disulfide (MoS2) in the lubricant, gives rise to an end product capable of withstanding high loads, high and low working temperatures, dirt and dust, aggressive chemical environments and extreme speeds.
The MoS2 is placed in the elastomer in the form of a dry lubricating film by deposition on the sealing surface. This produces a mechanical interlock, which reduces friction and wear caused by dynamic stress in the long term. The main advantages of this type of treatment are:
- It improves separation in automatic assembly.
- It reduces friction and dynamic stress.
- It controls contamination.
- It provides protection against corrosion.
- It dissipates heat.
- It transmits power.
- The process is suitable for all types of elastomers.
When used on O-rings, this static lubricant enables them to be used in advanced applications that require high electrical conduction, heat transfer, vacuum sealing and/or shear stability.
It is often necessary to improve the friction coefficient of O-rings, as they normally have rough and sticky surfaces. In these cases, surface treatments such as talc can be used. This method reduces friction, both to facilitate assembly and to prolong service life.
Treatment with talc consists of applying a powder coating to seals in a drum. No crosslinking with the elastomer surface occurs in this process.