The term ASBESTOS FREE GASKET or NON ASBESTOS GASKET commonly used in European and American countries refers to gaskets that are 100% asbestos free. Translated into Chinese, it can be said as "asbestos free gasket" or "non asbestos gasket", but in the Chinese market, some companies refer to gaskets containing a certain amount of asbestos (5-20%) as non asbestos gaskets, while gaskets that are 100% asbestos free are called non asbestos gaskets. In view of this special situation, we hereby reiterate that all gaskets operated by SealTex (our company) are asbestos free gaskets that do not contain any asbestos components.

What are the main materials of asbestos gaskets?

Non asbestos gasket is a type of sealing gasket made by stamping environmentally friendly non asbestos gasket materials as profiles, which can replace traditional asbestos gasket products. The main materials of environmentally friendly stone free gasket materials include reinforcing fibers (plant fibers, cork, inorganic fibers, etc.), binders, and fillers, which play different roles inside the gasket. Different reinforcing fibers, binders, and fillers can be combined to form different gasket materials.

1.Reinforced fiberCommon inorganic fibers include aramid fiber, carbon fiber, glass fiber, etc., which can provide tensile strength and structural stability

Commonly used aramid fibers as reinforcing fibers for gasket materials include ST-2058, AFM34, CSA-90

Carbon fiber reinforced: NA-1100, ST-2062

Glass fiber reinforced models include ST-2063, C4430, etc

2.fillerGraphite, mica, mineral powder, and other fillers can enhance sealing and temperature and corrosion resistance; Common models of asbestos free gasket materials filled with graphite include ST-2060, novatec HPN, ST-2067, etc

3.binderCommon adhesives for elastomeric substrates include nitrile rubber (NBR), ethylene propylene diene monomer (EPDM), chloroprene rubber (CR), styrene butadiene rubber (SBR), and fluororubber (FKM), which can endow gaskets with elasticity and sealing adaptability;

The models of asbestos free gasket materials using nitrile rubber as a binder include ST-2046, ST-2058, ST-2052, etc

The model of asbestos free gasket material with chloroprene rubber as adhesive is MP-15

The models of asbestos free gasket materials using styrene butadiene rubber as a binder include TS-9006, S-8091, TS-9013, NA-1035, AFM33/2, etc

By adjusting the material ratio and process, asbestos free gaskets can be adapted to different working conditions, such as oil resistance, acid and alkali resistance, or high temperature resistance

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What is the heat resistance of asbestos free gaskets?

The heat resistance of asbestos free gaskets depends on their formula and adhesive type, with a typical temperature range as follows:

1.Room temperature type(Cork rubber gasket, oil resistant paper gasket, asbestos free fiber paper gasket, etc.): Applicable temperature-29℃Up to 180 ℃Suitable for general industrial pipelines, small machines, gearboxes, transmission equipment, etc; Common models include Flexoid, Fibreflex, TS1521, TD1049, ST-2136, N-8092, S-8091, etc

2. Medium high temperature type (asbestos free fiber rubber sheet, PTFE sheet/modified PTFE sheet): usually used at temperatures<250 ℃, commonly used models include ST-2028-39, ST-2058, AFM34, TF1570 modified PTFE sheet, 24SH expanded PTFE sheet, etc., suitable for gasoline engines, diesel engines, industrial pump valves, petrochemicals, compressors, heat exchangers, food, pharmaceuticals and other industries.

3. High temperature type: With the high temperature resistance of graphite (able to withstand 1600 ℃ in an oxygen free environment), the special formula gasket can withstand short-term temperature and even break through500℃However, it is recommended to control long-term useWithin 400 ℃Metal lining can also be used in the middle to enhance its performance. The process is divided into sprinting and bonding, corresponding to our company's models ST-9926, ST-9916, ST-2067, novaform SK, etc., suitable for exhaust ports, ships, superchargers, various special equipment, etc

4. Ultra high temperature type: Ceramic fiber fiberboard: BARLON 8501200 1100bio, ISOPLAN 750, temperature resistance of 750~1250 ℃. Commonly used in industries such as steel, boilers, and burners

Mica composite board ST-4376, ST-4976, high temperature resistance of 700-1000 ℃, commonly used in high-temperature and high-pressure applications such as turbochargers and aircraft engines.

It should be noted that continuous high temperature can cause the aging of the elastomer, and long-term overheating may cause the gasket to harden, shrink or fail. Therefore, a comprehensive selection should be made based on the working pressure, medium corrosiveness, and other factors.

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What issues should be noted when choosing asbestos free gaskets?

1.Media compatibilityRubber adhesive needs to be non reactive with the medium (such as avoiding nitrile rubber in strong acid environments, and prioritizing fluororubber or PTFE gaskets)

2.Temperature and pressure matchingGraphite composite gaskets should avoid ultra-high temperatures (aerobic environment should not exceed 450 ℃), and PTFE gaskets should control pressure

3.Pre tightening force controlExcessive pre tightening force of bolts may cause the gasket to be crushed, and insufficient pre tightening force may also fail to achieve initial sealing. You can ask the technical personnel for the M and Y values of this material.

Certification compliance of asbestos free gaskets：

Restricted material testing: Generally, asbestos free gaskets must meet the basic RoHS and REACH regulations

Export to the EU must comply with DVGW, KTW-BWGL (Ell), WRAS, etc

Exporting to the United States requires certification such as NSF-61, CP65, UL, etc

The food and pharmaceutical industry needs to comply with certifications such as FDA and USP Class VI (PTFE gaskets can meet these requirements)