Industry new
Effect of Methanol on Different Rubber Materials
At present, the global demand for methanol is constantly changing and developing. The hydraulic crushing method has made the price of natural gas increasingly lower. By 2017, North America is considered to be a net exporter of methanol. A recent article written by a chemical engineer “The Transformation of Methanol Roles” (July 2014) shows the importance of methanol because methanol can be used to produce many other basic compounds.
We see the constant consumption of traditional gasoline and biodiesel production, but methanol can be seen as a renewable energy source. Methanol can also be widely used in the petrochemical industry, and products such as enamel coatings, adhesives, and synthetic rubber can be made.
Due to the continuous increase in the production and use of methanol, two potential points of failure with the methanol-related rubber seals occur:
1, the current seal is already in use if methanol as an additive may cause the rubber to expand.
2, the production of methanol used in the sealing process equipment.
The effect of methanol on the volume expansion of different rubber elastomers is also different. In practical sealing applications, choosing the right rubber elastomer makes it important that the expansion coefficient is within the specified range.
In current seals, especially in the automotive industry, standard dimer FKMs are used as materials in fuel systems. By adding an additional 10% methanol, or the new E85 standard, the seal will expand in volume due to methanol contact. Loss of sealing effect. New methanol-resistant seals are in urgent need of development.
Temperature range and contact are crucial for selecting a new seal design. In fact, FKM compounds have the largest volume expansion rate, which is contrary to the traditional idea, the traditional idea is that FKM is the most chemical-resistant rubber elastomer.
Fluorine rubber:
The advantage of fluoroelastomer is that the material is not used in any formulation oil, which is very important. Because methanol is a very good solvent, plasticizers can be extracted from rubber elastomers. This depends on how methanol is used, otherwise it may cause pollution problems.
In fact, the use of high-fluorine content polymers is very necessary, such as ternary copolymer fluorine rubber, this fluorine rubber has a good resistance to methanol. If there is a mixture of solvents, it is necessary to use a higher grade of chemical resistant fluoroelastomers, such as ETP fluoroelastomers.
Although perfluoroelastomer is the best chemically resistant rubber elastomer, the price of this material is several thousand dollars per pound, making this material not the best option because cost is a major factor.
Nitrile rubber:
Another alternative is a nitrile rubber compound that can withstand a wide range of temperatures with a low volume expansion rate. However, a defect of nitrile rubber is that it is not resistant to ozone, so if the seal of nitrile rubber is exposed to the environment, it will have a short service life, mainly due to the deterioration of ozone on the nitrile rubber compound. In addition, 10% plasticizers are usually extracted.
Hydrogenated nitrile rubber:
Hydrogenated nitrile rubber is a rubber elastomer similar to nitrile rubber but is resistant to ozone. Hydrogenated nitrile rubber provides improved physical properties and has better abrasion resistance compared to other rubbers. It also has a wide temperature range and dynamic performance, making it the ideal material for the oil and gas industry. In addition he usually contains a small amount of plasticizer, which also reduces the extraction.
Silicone and Silastic:
Both silica gel and silica gel have good resistance to methanol. The temperature range of these two materials is very wide, but it is not recommended to use in dynamic sealing, because these two materials have poor tear strength and poor wear resistance. Both of these materials are ideal for use in low temperature seals, and are also very good for use under the hood.
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