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Kalrez W240

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Kalrez® W240 perfluoroelastomer parts are a black product for photovoltaic wet manufacturing processes requiring a wide range of chemical resistance. W240 provides an excellent combination of properties (resistance to acids/bases) and is the product of choice for wet processes as an upgrade from standard elastomers, i.e., FKM, NBR, EPDM, etc. A maximum service temperature of 230°C is suggested.


  • Excellent resistance/low volume swell in a wide range of wet chemistries (acids/bases)
  • Excellent resistance to amine-based chemistries versus standard elastomers
  • Low metals content
  • Very good mechanical strength/compression set properties

Suggested Applications

  • Wet etch tools
  • Roller applications for wet inline tools
  • Wet chemical management systems
  • Filter, pumps, etc., for wet process applications

Typical Physical Properties1
Color Black
Hardness2 , Shore M (O-ring) 79
100% Modulus3 , MPa 7.85
Tensile Strength at Break3 , MPa 19.08
Elongation at Break3 , % 159
Compression Set4 , %
70 hr at 204 °C
Maximum Service Temperature5, °C 230

1 Not to be used for specification purposes
2 ASTM D2240 and D1414 (AS568 K214 O-ring test specimens)
3 ASTM D412 and D1414 (AS568 K214 O-ring test specimens)
4 ASTM D395B and ASTM D1414 (AS568 K214 O-ring test specimens)
5 DuPont proprietary test method

Chemical Resistance

For many applications, low volume swell/weight gain (change) of elastomers is critical for proper equipment operation. Excessive swell/weight gain (change) may cause permanent seal failure due to equipment hang-up, extrusion, etc. While other physical property testing may be needed to adequately define product performance in a particular application, volume swell/weight gain (change) is an excellent indicator of resistance to chemical attack. Table 1 provides chemical resistance (% volume swell) test data for Kalrez® W240 in various acids, bases, solvents and water. Table 2 compares the weight gain and volume swell of Kalrez® W240 versus standard FKM in an amine-based chemistry.

Table 1: Chemical Resistance, % Volume Swell1,2

Chemical Exposure Time Temperature (°C) % Volume Swell Kalrez® W240
Acetic Acid 70 100 4
Ammonium Hydroxide 70 100 4
Ethylene Diamine 70 90 5
Nitric Acid (70%) 70 85 1
Nitric Acid (70%) 672 85 3
Sulfuric Acid (98%) 70 150 3
Sulfuric Acid (98%) 672 150 5
Toluene 70 100 7
Toluene 672 100 6
Water 70 225 6

1 ASTM D471 and D1414 (AS568 K214 O-ring test specimens)
2 Please consult a Daemar Application Engineer to asses performance fit in your specific application

Table 2: Amine-Based Chemistry Resistance (MEA: DMSO 70:30 Mixture)1,2

Property Kalrez® W240 % Volume Swell Competitive FKM K7
Weight Change, % 1.0 Test Specimen Melted
Hardness Change, pts. -3 Test Specimen Melted
Surface Condition After Exposure No Surface Degradation Test Specimen Melted

1 MEA = Monoethanol Amine; DMSO = Dimethyl Sulfoxide
2 DuPont Proprietary Test Method: 14 days @ 80ºC

Download the Kalrez® W240 technical sheet.


Standard Kalrez® O-Ring Compounds

Daemar DMR O-Rings Kalrez

Kalrez® Compounds – 4079

4079 perfluoroelastomer parts are a black, low compression set product for use in many dry and wet semiconductor process environments. It has excellent chemical resistance, good mechanical properties and outstanding thermal stability.


Kalrez® Compounds – 6375

6375 is designed to give outstanding performance in the widest possible range of chemicals and temperatures. This product is an excellent choice for use in acids, bases, amines, steam, ethylene oxide, and many other aggressive chemicals.


Kalrez® Compounds – 7075

7075 is designed for general-purpose use as O-rings or custom sealing components in the chemical and hydrocarbon processing industries. It is a carbon black-filled compound with mechanical properties designed for improved sealing performance in temperature cycling applications. 7075 has improved thermal resistance that extends maximum service temperature to 327 °C (620 F).


Kalrez® Compounds – 0090

0090 perfluoroelastomer parts deliver durable, reliable sealing solutions for applications requiring excellent rapid gas decompression (RGD) properties as well as high hardness and high modulus properties. Some application areas include downhole equipment such as drilling and completion tools as well as industrial equipment including pumps and valves.

Specialty Kalrez® O-Ring Compounds


Kalrez® Compounds – 1050LF

1050LF is a carbon black-filled product for O-rings, seals, and other parts used in chemical process industries. It has good hot water/steam, and excellent amine resistance. Kalrez® 1050LF is not recommended for use in organic acids, or inorganic acids at high temperatures.


Kalrez® Compounds -6380

6380 is a non-black product specifically developed for chemical processes involving hot, aggressive amines. It has also been successfully used in applications involving highly oxidizing chemicals. In addition, it has excellent overall chemical resistance. This cream colored product is easily identifiable when selecting an O-ring material for harsh chemical plant services.


Kalrez® Compounds -7090

7090 is a product for uses requiring higher hardness/higher modulus than more typical applications. Kalrez® 7090 perfluoroelastomer parts are well suited for both static and dynamic applications as well as specific sealing applications requiring extrusion resistance at high temperatures.


Kalrez® Compounds -0040

0040 -is a black product specifically designed for low temperature environments where significant chemical resistance is required. Kalrez® 0040 parts maintain elasticity and seal force at temperatures unattainable by other perfluoroelastomers.



Kalrez® is a registered trademark of E.I. du Pont de Nemours and Company or its affiliates












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