Difference Explained Between Nylon 6 & Nylon 66

 

In today’s world both Nylon 6 and Nylon 6 are widely used synthetics polymer. They have played a vital role in growth and innovation during last few decades. Here we will be examining the properties (similarities and differences) so you can make an informed choice while making a choice between the two.

 

Introduction to Nylon 6 and Nylon 66 :

 

Nylon 6 and Nylon 66 are both polyamides, where the number represents the quantity and type of carbon atoms in the chemical structure.

 

Nylon 6 is made from caprolactam, which consists of 6 carbon atoms, while nylon 66 is made from adipic acid, which has 6, and hexamethylene diamine, which also has 6.

 

History of Nylon 6 and Nylon 66 :

 

In 1930, Du Pont discovered Nylon 66 which was the first synthetics fibre in the world.

 

In 1939, Paul Schlack discovered Nylon 6.

 

Both of them due to their very attractive properties were accepted quickly thus becoming the backbone of the synthetics fibre industry.

 

Technical comparisons of Nylon 6 and 66

 

• The number of units within the polymer chains of nylon 6 and 66 is 130 and 65 respectively.
• Both iterations comprise weak basic amino acids and acidic carboxylic acid end groups.
• They are both strong fibres of moderate elasticity, even after being drawn.
• Both nylons have high tenacity variants that are applied to industrial applications, and both have multiple strands of property definitions based on changes in polymerisation and drawing conditions.
• Nylon 6 has a lower elastic modulus and better elastic recovery and therefore provides softer, more flexible fabrics.
• At higher temperatures, like 180°c, nylon 6/6 shows markedly better heat age strength at 11.5kg, compared to nylon 6 of only 2.5kg.
• The fibres of nylon 66 are 33% more resistant to abrasion than nylon 6, withstanding up to 60,000 cycles compared to 40,000 in the case of nylon 6.
• With low creep, and more crystallinity, nylon 66 is slightly more rigid, allowing good stretch recovery and higher abrasion resistance.

 

Properties of Nylon 6 vs Nylon 66

 

Both Nylon 6 and 66 are different in many ways but there are many similarities too. Below we have underlined some key core performance characteristics :

 

 

• High Rigidity, stiffness and toughness.
• High mechanical strength
• Good Electrical Insulation
• Exemplary resistance to high energy radiation
• Superior sliding properties
• Top-Notch mechanical damping ability
• Outstanding wear resistance
• Good machinability
• High fatigue resistance

 

 

Nylon 6 vs Nylon 66: Differences and Comparisons

 

NYLON 6	NYLON 66
Less crystalline	More crystalline
Lower mould shrinkage	Exhibits greater mould shrinkage
Lower melting point	Higher melting point
Lower heat deflection temperature	Higher heat deflection temperature
Higher water absorption rate	Lower water absorption rate
Poor chemical resistance to acids	Better chemical resistance to acids
Withstands high impact and stress and better stands up to hydrocarbons	Better stiffness, tensile modulus and flexural modulus
Lustrous surface finish, easy to colour	More difficult to colour

 

 

The most remarkable difference between Nylon 6 and 66 is the mould shrinkage. As Nylon 6 has low mould shrinkage it is more reliable in terms of final part dimensions whereas Nylon 66 higher mould shrinkage makes it skepctical to alteration of dimensions of manufactured goods.

Other notable important differences are their heat deflection value and water absorption rate. Due to higher water absorption and less heat deflection it is less durable in applications where high temperatures are used and more water exposure. In this case Nylon 66 is the preferred choice.

Typical Material Apllications:

Nylon 6:

• Stadium seats
• Hosiery
• Radiator grills
• Industrial yarn
• Toothbrush fibres
• Wear Strip and Chain Guards
• Machine Guards
• Rotor slot wedges
• Firearms
• Upholstery
• Heavy-duty fabrics
• Circuit insulation boards
• Switchgear
• Seals

Nylon 66 :

• Friction bearings
• Tire cord
• Carpets
• Battery modules
• Automotive airbags
• Conveyor belts
• Parachutes
• Apparel
• Seat belts

 

Final Thoughts :

So after having to know both Nylon 6 and 66 we now know that both have some similar properties but yet due to certain differences the type of application is different. One needs to take into consider processing, aesthetics, appearance and mechanical properties first beforehand.

Nylon 6 has better appearance due to its easy to dye property and lustrous finish. It is preferred mainly in lightweight engineering plastic where high impact and stress is involved. It is the absolute option to go for applications in industries like automotive, industrial and military. As we already know that it is not to be used in applications with high temperatures and expose to water.

Nylon 66 is used in engineering plastic that requires exposure to higher temperatures. Plus the stiffness and good tensile property makes it ideal for applications that required long term performance.