Nylon 6 or Nylon 66 - Which One Should I Choose?

Nylon (PA) 6 & 66 are both synthetic polymers called polyamides, with the numbers describing the type and quantity of polymer chains in their chemical structure. Most nylons, including 6 & 66, are semi-crystalline and possess good strength and durability for demanding applications.  

Check now

Nylon Properties

As polyamides, Nylon 6 & 66, whilst having their own separate and distinct benefits, do share many of the same core properties:

• High mechanical strength, stiffness, hardness and toughness.
• Good fatigue resistance.
• High mechanical damping ability.
• Good sliding properties.
• Excellent wear resistance
• Good electrical insulating properties
• Good resistance to high energy radiation (gamma & x-ray).
• Good machinability.

Differences

So whilst Nylon 6 & 66 are very similar materials, they do provide slightly different characteristics. The reason for the differences is largely due to their differences in chemical structure. Nylon 6 is made from one monomer which has 6 carbon atoms whilst Nylon 66 is made from 2 monomers with each one having 6 carbon atoms, hence the Nylon 66 name.

NYLON 6

NYLON 66

Less crystalline

More crystalline

Lower mold shrinkage

Exhibits greater mold 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

An important difference between Nylon 6 & 66 is mold shrinkage. Nylon 6&#;s lower mold shrinkage adds reliability to final part dimensions which is beneficial whilst Nylon 66&#;s greater mold shrinkage, as it is exposed to cool air and solidifies, means the material&#;s shape changes more after processing, which must be accounted for.

Other key differences between the two nylons are water absorption rates and heat deflection temperatures. As Nylon 6 absorbs more water than Nylon 66 and has lower heat deflection temperatures, it is not suited to applications that are exposed to water at high temperatures. Nylon 66 would be a better choice between the two.    

Typical Material Applications

• Sleeve and slide bearings
• Wear pads
• Support and guide wheels
• Cable sheaves
• Hammer heads
• Scrapers
• Gear wheels
• Seal rings
• Cutting boards
• Track plates

Which One Should I Choose?

The needs of an application have to be considered in terms of processing, aesthetic appearance, and mechanical properties first, in order to decide whether Nylon 6 or 66 is more suitable.

Nylon 6 should be used if a lightweight engineering plastic is required to withstand high impact and stress. It has better aesthetic appearance than Nylon 66 due to its lustrous finish and is easier to dye. It is an ideal choice for applications in the automotive, industrial and military industries. Common applications include: gears, firearm components and automotive engine compartments. It is not ideal, however, for applications that are exposed to water at high temperatures due to its higher water absorption and lower heat deflection rate than Nylon 66, which would be a better choice.

Nylon 66 should be used if a high performing engineering plastic is required that will be exposed to higher temperatures. Additionally, its stiffness and good tensile and flexural modulus make it an ideal material for applications that need repeated long-term performance. Typical applications include: friction bearings, radiator caps and tire ropes. 

Time : -07-31

Hits : 92

Nylon 6 and Nylon 66, are two materials of strength, toughness, and workability.

Setting aside these common benefits, there exist important differences between the chemical structure, melting point, strength and durability, moisture absorption, wear resistance, and industrial applications of these two materials.

Interested in knowing which one would best fit your purpose? Nylon 6 has fine dyeability and good flexibility; thus, performance is also very good in textiles and carpets.

On the contrary, Nylon 66 has its great properties operating under high-temperature and friction environments; hence, application fields will be auto parts and industrial machinery.

This will go a long way in making you understand the exact differences between Nylon 6 and Nylon 66, hence positioning you better in making the most appropriate choice for all your requirements for application purposes.

Nylon 6 And Nylon 66 Differences & Comparisons

Nylon 6 consists of one monomer, caprolactam, which contains 6 carbon atoms. On the other hand, nylon 66 is formed from the condensation of two monomers: adipic acid, thus called "66".

The semi-crystalline nature of Nylon 6 and Nylon 66 reveals they have ordered molecular structures that coexist with non-ordered molecular structures.

Hence, they possess strength combined with flexibility, making them suitable for high-strength projects.

Now, after knowing the differences between Nylon 6 and Nylon 66, one can let oneself make a choice for the right material to serve the purpose.

The table shown below will compare and explain their difference in characteristics.

Read more:Nylon polyamide fiber properties and applications

Resistance to Hydrocarbons

Nylon 6 has far better resistance to hydrocarbons compared to Nylon 66.

Thus, it can be used where such chemicals are present more safely.

Mould Shrinkage

Nylon 6: The shrinkage associated with this Nylon is less during the molding process, making the dimensions of the final parts more reliable. 

Nylon 66: It has higher mold shrinkage, which makes the size of the final product more variable.

Impact Resistance

Nylon 6 has higher impact resistance compared to Nylon 66 and is ideal in high durability applications.

Easiness to Colour

Nylon 6: This produces a shiny bright color, which gives the nylon a more beautiful appearance.

Nylon 66: Less brilliancy, more difficulty in dyeing.

Water Absorption Speed

While Nylon 6 quickens water uptake as compared to Nylon 66, it has some effect on its mechanical properties in a humid environment.

Recyclability Potential

In this respect, Nylon 6 is privileged with higher recyclability potential owing to fewer and less complicated production and reprocessing steps.

Molecular Mobility

This means Nylon 6 exhibits superior molecular mobility to Nylon 66 and hence superior flexibility and easier processability.

Elastic Recovery

Nylon 6 tends to show better elastic recovery, and this factor will be useful in applications where materials are subjected to distortion and have to return to their original shape.

Dye Affinity

An improved dye affinity in nylon 6 materialized into better and more intense coloration.

Crystalline Structure

Nylon 6: The formation of the crystalline is less structured, hence more flexible.

Nylon 66: It has a denser and more organized crystalline structure, hence it is more rigid.

Heat Deflection Temperature

It is for this reason that the heat deflection temperature for Nylon 66 is higher; hence, it will do better in high-temperature applications.

Melting Point

Nylon 6: The melting temperature range will be from 215°C to 220°C.

Nylon 66: This will be seen to melt at a higher range of 250°C to 265°C.

Chemical Acid Resistance

Nylon 66 provides a higher level of resistance in acidic environments than Nylon 6.

sft contains other products and information you need, so please check it out.

Rigidity

Nylon 66 is more rigid than Nylon 6, which can be advantageous in structural applications.

Nylon 66 is more rigid than Nylon 6, which is beneficial in structural applications.

Colour-Fastness

Nylon 6 has better color-fastness and resists fading much better when exposed to sunlight and detergents.

Temperature Resistance

Nylon 66 has better temperature resistance and can support high-temperature applications.

Ability to Clean

Nylon 6 is generally easier to clean, hence more suitable for textiles and consumer goods.

Elastic Modulus

It has a high elastic modulus, hence it is very strong in tension. 

Internal Structure

Nylon 6: Less density in the internal structure gives more flexibility to this material. 

Nylon 66: More density within the internal structure provides more strength and stiffness.

Polymerization Formation

Nylon 6: Ring-opening polymerization.

Nylon 66: Condensation polymerization.

Moisture Regain

Both Nylon 6 and Nylon 66 display similar moisture regain at 4-4.5%.

Monomer Requirements

Nylon 6: Only one type of monomer is required for its polymerization.

Nylon 66: Two different types of monomers are required.

Density

Nylon 6: Around 1.2 g/ml.

Nylon 66: Slightly lower at 1.15 g/ml.

Degree of Polymerization

Nylon 6: Around 200.

Nylon 66 has contributed to continued use at temperatures as high as 210°F, above the 200°F limit of Nylon 6.

This makes Nylon 6/6 slightly better where temperatures are higher.

Nylon 6/6 has far better acid resistance than the chemical resistance of Nylon 6. 

That would mean that Nylon 66 has greater strength and can be more reliable in areas where harsh chemicals are likely to be high.

If you are doing a job where you may be exposed to strong acids or hazardous chemicals, Nylon 66 will be better and safer.

Knowing these key differences will give you greater knowledge and help you answer which is the best fit for your specific expectations.

The information will help you understand the difference between Nylon 6 and Nylon 66 in addition to which is better for specific needs.

Also Read:Unlocking the Versatility of Polyamide 6 & 66: Applications, Uses, and Key Properties

People Also Ask About Nylon 6 and Nylon 66

What are the main uses of Nylon 6 and Nylon 66?

Because Nylon 6 costs so much less and is a much better mechanical, it has found a wide range of applications&#;from carpets and textiles to industrial plastics, where one can recommend otherwise, the uses that it is high strength&#;for example, automotive parts, electrical components , and appliances&#;Nylon 66 In effect, tensile strength, thermal resistance, and chemical resistance may well suit nylon 66 applications where performance forward Expected attributes.

How do Nylon 6 and Nylon 66 differ in chemical composition?

The biggest difference is in the most important, depending on the chemical composition. Nylon 6 is a single-chain polymer derived from a single monomer, Nylon 66 is a double-chain polymer with two monomers, hexamethylenediamine and adipic acid, polymerized by polycondensation These structural differences complicate and complicate the synthetic mechanism of nylon 66 crystal size Thus, Nylon 6 offers better mechanical properties than Nylon 66 .

Is Nylon 66 more durable than Nylon 6?

Yes, Nylon 66 is more mechanically resilient than Nylon 6.

The stiffer and more crystalline constitution of Nylon 66 confers it with better tensile strength, heat resistance, and chemical resistance in comparison with Nylon 6.

This is the reason that these good mechanical properties conferred on Nylon 66 make it possible to sustain stresses and hard uses in many diversified and demanding applications.

From here we can make it clear why and when the application of Nylon 66 is only imparted when high-end strength and reliability to the product's application are in consideration&#;for instance, car parts or any equipment of the like.

Are Nylon 6 and Nylon 66 resistant to acids?

Both of them have quite passable acid resistance, but generally speaking, Nylon 66 has better acid resistance.

Because Nylon 66 has a much more rigid and crystalline structure, it gives less of a chance for some sort of chemical degradation pathway in case it encounters an acidic environment.

Enhanced acid resistance makes Nylon 66 more suitable for applications where its material may come in contact with acidic materials, such as in some industrial or chemical processing environments.

Which nylon is better for automotive applications, Nylon 6 or Nylon 66?

Nylon 66 typically has more preferences in automobile applications than Nylon 6 due to improved mechanical properties.

With better tensile strength and heat resistance, along with dimension stability, Nylon 66 becomes a material more effective at performing its duties against the harsh conditions it will meet in the automobile environment, including high temperatures, vibrations, and mechanical stresses.

These various properties of Nylon 66 would lend to it a better choice than Nylon 6 for application in which part has to perform for lifetime of the vehicle and retain integrity of vehicle.

How does the production process differ between Nylon 6 and Nylon 66?

Only one monomer is involved in Nylon 6, called caprolactam. To produce Nylon 66 through stepwise polycondensation, two monomers&#;hexamethylenediamine and adipic acid&#;have to be combined.

Additional work of stepwise polycondensation for two monomers adds to the rigors of processing Nylon 66 and makes it more resource-intensive; hence, it is more expensive to manufacture compared to Nylon 6.

What factors should I consider when choosing between Nylon 6 and Nylon 66?

Some of the main factors that will always be based on making a choice between Nylon 6 and Nylon 66 revolve around mechanical properties required in the application, such as tensile strength, heat resistance, and chemical resistance; secondly, the manufacturing process and associated costs.

Generally, Nylon 66 should be specified for use in applications where better performance is called for, such as in automotive and industrial components, due to its better mechanical properties.

While Nylon 6 could be more economical in lower-grade applications where better performance properties of Nylon 66 would not be of significance.

Is Nylon 66 more expensive than Nylon 6?

Yes, Nylon 66 will always be more expensive than Nylon 6. The major reason has to do with the considerably more complicated manufacturing process defining Nylon 66.

More steps, in addition to raw materials, are needed to prepare the two monomers and to complete the actual polycondensation reaction; hence, making it more costly to produce Nylon 66 compared with Nylon 6 where one step in polymerization does the job.

It means the additional production cost of Nylon 66 is added on to the market price of the material in comparison with Nylon 6.

In summary, Nylon 6 and Nylon 66 are both high-performance engineering materials with very special advantages: good dyeability, flexibility, and property in textile and carpet applications are the strong points of Nylon 6;high temperature and frictional environments can easily be dealt with because of the high performances provided by Nylon 66, thus making it a top choice for auto parts and industrial machines.

It largely depends on application requirements. That makes it important for the user to consider different factors, such as the mechanical properties desired, thermal stability, and conditions under which the operating environment is going to be, in order to determine the type of nylon that best fits the application.

This comparative analysis provides the proper fundamental base for the selection of appropriate nylon materials to be used in a wide range of industrial and consumer applications.

Contact us to discuss your requirements of nylon 66 yarn. Our experienced sales team can help you identify the options that best suit your needs.