Which Elastomer Offers The Best Weather Resistance?
When a product is required to operate in an outdoor environment, in one where it is either continually or at certain times exposed to the elements, there comes a need to select a base elastomer which offers the best weather resistance.
Certain elastomers perform better than others in different environments, however having a core understanding as to which offers the best base for a product helps to steer a brief and develop a detailed specification further.
In selecting a rubber which can withstand the elements for use in any particular application, it is necessary to understand the different ways in which the weather can affect any given elastomer, with the most common being:
- Ozone & UV
- Inclement Weather Conditions
When a product or component is exposed to direct sunlight, it’s internal temperature can be increased to more than 60°C and this heat cycling can accelerate compression set in many materials.
In perhaps a complete opposite to exposure to direct sunlight, components and products operating at the opposite end of the spectrum, in near-to or sub-freezing environments can be susceptible to cracking, with further problems intensifying when returning to temperatures above 0°.
Ozone & UV
Ozone not only occurs naturally but can also be generated in instances such as outdoor enclosures which commonly house electrical equipment. Exposure to UV can also be detrimental to the lifespan of a component and result in cracking or disintegration.
Inclement Weather Conditions
Inclement weather conditions can take the form of humidity, dew, rain, snow, frost or hail, depending upon the ambient temperature and when this moisture is combined with solar radiation, can contribute significantly to the weathering of base materials. As a result of both mechanical stresses imposed on a material when moisture is absorbed or desorbed and to the chemical participation of moisture in the chemical evolution. In conjunction with the effects of temperature upon a material, the freeze/thaw cycling caused by inclement weather conditions can cause structural failures or accelerate degradation where already initiated.
Selecting the correct elastomer for a particular application where exposed to the elements and, as such, subject to weathering, alongside ‘compounding’ it with ingredients which will fine tune many of the above properties is essential and something which White Cross Rubber Products pride themselves on.
Primarily utilising 12 different elastomers for the manufacture of both rubber sheeting, reinforced rubber sheeting and rubber coated textiles, our technicians are on hand to help inform decisions and to help make the research stage that little bit more straightforward.
Below you’ll find a comparison of our 12 most commonly utilised elastomers based upon their weather resistance properties rated ‘poor’ to ‘excellent’:
Please note: Whilst most main rubbers are outlined below, our capabilities and experience allow us to manufacture a much wider range of blends and formulations. The inherent characteristics of a polymer can be improved through the inclusion of additives, including the weather resistance properties.
|Natural Rubber||Poor / Fair|
|SBR||Poor / Fair|
Whilst clearly faced with a number of options in terms of elastomers offering ‘excellent’ Ozone and weather resistance, the following examples showcase commonly used base materials which help to minimise the impact of harsh weather conditions upon a product or component.
Butyl is commonly used as a base material due to it’s strong resistance to sunlight, ozone and heat aging, as well as other properties which give it exceptional resistance to gas and moisture (water and steam) permeation. Butyl also offers good resistance to dilute acids and alkalis as well as good low-temperature flexibility.
EPDM is compatible with a wide variety of other materials when manufacturing blends specific to a particular application and exhibits outstanding weather resistance, making it a sound choice for use when products or components are exposed to the elements. EPDM has the ability to resist the deteriorative effects of ozone, oxygen, heat, and weather, along with a range of chemicals and dilute acids and alkalis.
Hypalon is one of the most weather-resistant base materials available with both sunlight and UltraViolet light having few adverse effects upon its physical properties. Whilst many elastomers start to degrade by ozone concentrations of 1 ppm in air, Hypalon remains unaffected by concentrations as high as 1 part per 100 parts of air. It’s excellent ability to accept pigmentation also means that coloured Hypalon compounds do not fade in extended exposure to sunlight and UV.
In comparison to other elastomers, Polyurethane offers excellent abrasion resistance and tensile strength, both of which translate to a superior performance in all weather conditions, as well as the material offering good resistance to Ozone and operating temperatures as low as -50°C and as high as 90°C.
Silicone is widely regarded as an extremely versatile material being highly resistant to oxygen, ozone, UV light, aging, weather, and extreme temperatures.
In many cases, material selection needs to be a compromise with a number of different factors coming into play including the individual usage specifications, not forgetting the economics of a particular situation.
Should you be looking for more in-depth, backed up information and data surrounding the weather resistance of any number of our main elastomers, we welcome you to give our technicians a call on 01524 585200 where we will be only more than happy offer guidance and assistance.