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2022
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What is VMQ?
For a number of sealing solutionswe use VMQ, which is also available as LSR (Liquid Silicone Rubber) material. But what exactly is a VMQ or LSR material? Silicone (VMQ) is a group of elastomers made from silicon, oxygen, hydrogen and carbon. The characteristics of silicone compounds (VMQ) are:
- Extreme temperature range
- Very plastic behaviour
- Very good resistance to excessive stretching
- Low temperature flexibility
- Easy to colour according to RAL numbers
- Single transparent elastomer
Specially developed types
As a group within the elastomers, VMQ has a relatively low tensile strength, severe limited chemical resistance and low abrasion resistance. For these reasons VMQ materials should only be used statically. Special types have been developed for their exceptional resistance to heat and high insulation value. All available types with very specific properties are generally not 1 on 1 comparable to the values of conventional rubber.
What is VMQ resistant to?
Depending on the type selected, VMQ can be used in different markets thanks to its diversity of resistance. Depending on the type selected, VMQ is resistant to:
- Hot air (Very Good)
- Ozone (Very Good)
- UV radiation (Very Good)
- Engine and transmission oils (Good – Moderate)
- Animal and vegetable fats and oils (Good – Moderate)
- Some brake fluids (Good – Moderate)
- Mineral oils (Good – Moderate)
Excellent resistance to extreme temperatures
In general, silicone has excellent resistance to extreme temperatures from -50 ° C to +232 ° C (-58 ° F to +450 ° F). Special VMQ types are even suitable for higher system temperatures up to 275°C with short-term light above 300°C. The preservation of the properties of silicones at high and low temperatures is superior to most other elastomers.
Electrically insulating, -conductive or flame-retardant
Silicones can be specially formulated to be electrically insulating, – conductive or flame-retardant. Many silicones have a higher-than-normal shrinkage during the vulcanization process, so moulds for products in silicone often differ in size from moulds for other elastomers.
VMQ is recommended for static sealing applications
VMQ materials have a relatively low core resistance and a high coefficient of friction so they are only recommended for static sealing applications. When post-treated, silicones do not give off any smell or taste and are also very clean, making them particularly suitable for many food and medical applications .
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