NR Seals


NR is the abbreviation for natural rubber.

The raw material is extracted from the milky sap of rubber plants and is primarily important as a base material for other rubber compounds in the entire elastomer industry.

NR/SBR is a compound consisting of natural and styrene-butadiene rubber and is the most widely used rubber compound for a wide range of the simplest applications, thanks in part to the excellent mechanical and dynamic properties of this material.

NR Seal-1

NR materials available from Rehm-Dichtungen Ehlers GmbH

We purchase part of the NR as rolls and sheets from the manufacturer Semperit. Here we divide the material qualities into three ranges that are suitable for different applications.

The NR/SBR qualities A9506, A618 and A621 are referred to as Commercial Standard quality. These are qualities that consist mainly of SBR components and only a very small proportion of NR. These qualities are suitable for simple applications and are in the lower price segment. A9506 can be supplied with one or two glass fibre inserts on request. This increases the tensile strength somewhat. The qualities A618 and A621 are tested PAH-free (BfR XXI category 1 and FDA 21 Food and Drugs Part 177.2600) and are suitable for use in the food sector.

A160, A560 and A654 are classified as para grades. They consist almost exclusively of NR and therefore have the best mechanical properties. The wear protection grade A590 contains slightly more SBR than the Para grades. This makes them less expensive, but they still have good mechanical values and excellent abrasion values.

In addition to Semperit NR/SBR, we also source various import qualities.

Paraqualities

A160 NR

Technical data sheet:

A160 NR

Properties:

Hardness [Shore A] ISO 7619-1 40 +-5
Density [g/cm³] ISO 1183 Approx. 1.08
Tensile strength [N/mm²] ISO 37-S2 15
Elongation at break [%] ISO 37-S2 550
Abrasion [mm³] ISO 4649-A 110 [5N]

 

Approvals and certifications:

  • highly elastic
  • Excellent mechanical properties
  • PAH - fully complies with GS Cat. 3
  • Corresponds to WDK guideline 2201
A560 NR

Technical data sheet:

A560 NR

Properties:

Hardness [Shore A] ISO 7619-1 40 +-5
Density [g/cm³] ISO 1183 Approx. 1.06
Tensile strength [N/mm²] ISO 37-S2 18
Elongation at break [%] ISO 37-S2 600
Abrasion [mm³] ISO 4649-A 110 [5N]

 

Approvals and certifications:

  • highly elastic
  • Excellent mechanical properties
  • PAH - fully complies with GS Cat. 3
  • Corresponds to WDK guideline 2201

Materials for food contact

A618 NR/SBR light 45 Shore

Technical data sheet:

A618 NR/SBR light 45 Shore

Properties:

Hardness [Shore A] ISO 7619-1 45 +-5
Density [g/cm³] ISO 1183 Approx. 1.28
Tensile strength [N/mm²] ISO 37-S2 12
Elongation at break [%] ISO 37-S2 550

 

Approvals and certifications:

  • Food quality
  • BfR XXI Category 1 (For consumer articles that come into contact with foodstuffs for longer than 24 hours when used as intended)
  • FDA 21 Food and Drugs Part 177.2600 for repeated contact with aqueous foodstuffs
  • PAH - fully complies with GS Cat.3
  • Corresponds to WDK guideline 2201i
A621 NR/SBR light 65 Shore

Technical data sheet:

A621 NR/SBR light 65 Shore

Properties:

Hardness [Shore A] ISO 7619-1 65 +-5
Density [g/cm³] ISO 1183 Approx. 1.43
Tensile strength [N/mm²] ISO 37-S2 8
Elongation at break [%] ISO 37-S2 380

 

Approvals and certifications:

  • Food quality
  • BfR XXI Category 4 (For consumer goods that are in contact with the food for a very short time or only with a very small surface area).
  • FDA 21 Food and Drugs Part 177.2600 for repeated contact with aqueous foodstuffs
  • PAH - fully complies with GS Cat.3
  • Corresponds to WDK guideline 2201

Commercial standard qualities

A9506 NR/SBR 70 Shore

Technical data sheet:

A9506 NR/SBR 70 Shore

Properties:

Hardness [Shore A] ISO 7619-1 70 +-7
Density [g/cm³] ISO 1183 Approx. 1.46
Tensile strength [N/mm²] ISO 37-S2 4
Elongation at break [%] ISO 37-S2 200

 

Approvals and certifications:

  • Standard quality
  • For low requirements
  • Corresponds to WDK guideline 2201
  • SVHC-free

Wear protection qualities

A590 NR/SBR 60 Shore

Technical data sheet:

A590 NR/SBR 60 Shore

Properties:

Hardness [Shore A] ISO 7619-1 60 +-1
Density [g/cm³] ISO 1183 Approx. 1.15
Tensile strength [N/mm²] ISO 37-S2 15
Elongation at break [%] ISO 37-S2 400

 

Approvals and certifications:

  • Technical sealing plate
  • Excellent mechanical properties
  • Conditionally weather resistant
  • antistatisch (spezifischer Durchgangswiderstand nach ASTM D 991 < 1 MegaOhm*cm)
  • Corresponds to WDK guideline 2201
  • SVHC-free

Import qualities

NR/SBR 50 Shore

Technical data sheet:

NR/SBR 50 Shore

Properties:

Hardness [Shore A] ISO 7619-1 50 +-1
Density [g/cm³] ISO 1183 Approx. 1.4
Tensile strength [N/mm²] ISO 37-S2 3
Elongation at break [%] ISO 37-S2 250
NR/SBR 70 Shore

Technical data sheet:

NR/SBR 70 Shore

Properties:

Hardness [Shore A] ISO 7619-1 70 +-10
Density [g/cm³] ISO 1183 Approx. 1.5
Tensile strength [N/mm²] ISO 37-S2 3
Elongation at break [%] ISO 37-S2 200
NR/SBR 70 Shore with insert

Technical data sheet:

NR/SBR 70 Shore with insert

Properties:

Hardness [Shore A] ISO 7619-1 70 +-10
Density [g/cm³] ISO 1183 Approx. 1.5
Tensile strength [N/mm²] ISO 37-S2 3
Elongation at break [%] ISO 37-S2 200
NR/SBR 70 Shore with insert, fabric patterned on one side

Technical data sheet:

NR/SBR 70 Shore with insert, fabric patterned on one side

Properties:

Hardness [Shore A] ISO 7619-1 70 +-10
Density [g/cm³] ISO 1183 Approx. 1.5
Tensile strength [N/mm²] ISO 37-S2 3
Elongation at break [%] ISO 37-S2 200
NR/SBR 80 Shore

Technical data sheet:

NR/SBR 80 Shore

Properties:

Hardness [Shore A] ISO 7619-1 80 +-10
Density [g/cm³] ISO 1183 Approx. 1.4
Tensile strength [N/mm²] ISO 37-S2 3
Elongation at break [%] ISO 37-S2 200
NR/SBR light 50 Shore

Technical data sheet:

NR/SBR light 50 Shore

Properties:

Hardness [Shore A] ISO 7619-1 50 +-10
Density [g/cm³] ISO 1183 Approx. 1.5
Tensile strength [N/mm²] ISO 37-S2 5
Elongation at break [%] ISO 37-S2 300
NR/SBR light 65 Shore

Technical data sheet:

NR/SBR light 65 Shore

Properties:

Hardness [Shore A] ISO 7619-1 65 +-10
Density [g/cm³] ISO 1183 Approx. 1.5
Tensile strength [N/mm²] ISO 37-S2 5
Elongation at break [%] ISO 37-S2 300

The advantages and material properties of NR/SBR at a glance

In addition to the named properties, the NR/SBR rubber has good compressive strength and good resistance to acetone and alcohol. Styrene-butadiene rubber is also considered to have excellent resistance to water and steam. Furthermore, the material is very ductile and shock-elastic. In addition, the temperature resistance is considered to be good. This makes this material suitable for many areas of application.

NR/SBR owns:

  • High elasticity
  • High cold flexibility
  • High tensile strength
  • High abrasion resistance

Only moderate resistance to numerous chemicals as well as alkalis and acids can be assumed. NR/SBR is also unsatisfactory in terms of its ageing resistance and resistance to ozone and UV light. The material is also not recommended with regard to fuels or cleaning agents containing solvents.

NR Permanencies at a glance

Material designationOzone and weather resistanceOil and petrol resistanceAcid resistanceStrong basesWear resistance
Semperit SBR A 9506not durablenot durableconstantconditionally stableNot suitable
Semperit NR-SBR A 618not durablenot durableconditionally stableconstantconditionally stable
Semperit NR-SBR A 621not durablenot durableconditionally stableconstantconditionally stable
Semperit NR SBR A 590not durablenot durableconditionally stableconstantwell suited
Semperit Para NR A 160not durablenot durableconditionally stableconstantwell suited
Semperit Para NR 560not durablenot durableconditionally stableconstantwell suited

Application areas of NR/SBR gaskets

NR/SBR seals can be used for hydraulic and pneumatic applications where high mechanical wear due to friction is to be expected. The interior of buildings or housings as well as UV-protected outdoor areas can be highlighted as a further area of application. Furthermore, the material is suitable as wear protection, abrasion protection as well as impact protection.

We will be happy to answer your questions about whether NR is also suitable as a sealing material for your purposes. Please contact our customer service, who will be happy to provide you with comprehensive advice.

FAQ

What are NR seals?
NR gaskets, also known as natural rubber, are classified as elastomer gaskets. The NR SBR gasket material is the most commonly used rubber compound for flat gaskets and related products.
What are the properties of NR seals?
Seals made of NR/SBR are characterised above all by good compressive strength. The material is also highly elastic, flexible at low temperatures and has high tensile strength and abrasion resistance. Finally, the material is expandable and shock-elastic.
What resistance do NR seals offer?
NR gaskets have a reduced number of resistances compared to the materials NBR or EPDM. In principle, the NR sealing material has a limited resistance to acids and is resistant to strong bases. Furthermore, NR seals have good wear resistance.
Can NR seals also be equipped with self-adhesive?
NR gaskets can be equipped with basic self-adhesive features. In the first production step, the roll or sheet material is glued with a self-adhesive film in order to subsequently produce your self-adhesive flat gasket.
Can NR SBR also be purchased by the metre?
We use all our sealing materials to produce the right seals for you using our various manufacturing processes - water jet cutting, plotting, punching. However, we are also happy to sell you NR SBR by the metre, in strips or in the form of rolls and sheets.
Which different NR qualities are in stock as standard?
We obtain part of our NR materials from the manufacturer Semperit, whereby we subdivide these into three different areas, depending on the intended use. The NR/SBR qualities A9506, A618 and A621 belong to the Commercial Standard quality. We consider both A618 and A621 to be food contact materials as they are FDA compliant. The sealing materials A160, A560 as well as A654 can be assigned to the para-qualities, while the A590 belongs to the range of wear qualities. In addition to the NR materials from Semperit, we also purchase various import qualities.