The Difference Between Nylon 6.6 and Nylon 6

Aug. 26, 2024

The Difference Between Nylon 6.6 and Nylon 6

Nylon is a family of polymers, and all nylons share certain characteristics. However,there are some significant differences among types of nylon. Not all nylons are the same.

Click here to get more.

Specifically, there are significant differences between Nylon 6.6 and Nylon 6, which are two commonly-chosen options for industrial sewing and thread applications. Here&#;s a closer look at their characteristics and why you might select one over the other.

Chemistry, Characteristics, and Choosing

Chemically speaking, Nylon 6 is one monomer with 6 carbon atoms. Nylon 6.6 is made from 2 monomers with 6 carbon atoms each, which results in the designation of 6.6.

Both can withstand high heat and are generally tough materials with good wear resistance. However, when you take a closer look, their individual characteristics become more clear.

Nylon 6

Nylon 6 has the core characteristics of any member of the nylon family, including its hardness, stiffness, and toughness. It has good mechanical dampening and insulation qualities.

It slides with minimal abrasion, resists fatigue, and is very wear-resistant over time. As an added benefit, it has good machinability and can be worked into its final form fairly easily. It also has a lustrous finish.

Nylon 6.6

Nylon 6.6 is similar to Nylon 6 but not the same. It has a higher melting temperature. At 160 degrees Celsius, Nylon 6.6&#;s heat age strength at break is 13.6 kg versus Nylon 6&#;s 12.0 kg.

When you increase the temperature to 180&#;, the difference becomes starker. Nylon 6.6&#;s heat age strength is 11.5 kg, while Nylon 6&#;s drops down to 2.6 kg. In some applications, this could make a huge difference.

Some industrial fiber processes, like tire cord, use heat to incorporate the fiber into the end product. Nylon 6.6 withstands these processes and continues to provide reliable strength well afterward. Nylon 6, by contrast, degrades or forces a change in the processes, reducing productivity.

Nylon 6.6 offers low creep, good stretch recovery, and higher abrasion resistance than Nylon 6 and most other materials you&#;ll find in the marketplace. In fact, its abrasion and heat resistance are the defining properties that make it a superior choice for industrial applications.

The fibers in Nylon 6.6 are 33% more abrasion resistant than Nylon 6 fibers, withstanding over 60,000 cycles over Nylon 6&#;s 40,000 cycles. In hard-wearing industrial fiber applications, this means much more reliable long-term performance.

Primary Uses of Nylon 6.6

Nylon 6.6 has several primary uses, including micro denier vs. heavy denier vs. high-tech. In its micro denier form, it is mostly used in apparel. It offers great toughness and wear resistance for high-performance sports gear and industrial workwear.

In its heavy denier form, it is used in tires and industrial products. In its high-tech form, you&#;ll find it in automotive airbags, parachutes, carpet, and other uses where extreme performance, durability, and reliability are of the utmost importance.

Primary Uses of Nylon 6

The major use of Nylon 6 is in industrial yarn. It is found in cords, heavy-duty fabric, toothbrush fibers, and many other products that rely on tough industrial nylon for a blend of strength and flexibility.

Nylon 6 is also found in fabrics with a certain type of desirable fashion sheen like hosiery, chiffon, and organza. This is due to the lustrous surface finish that is unique to Nylon 6.

A Comparison Table

To help you examine the differences between Nylon 6.6 and Nylon 6, we created this helpful table. On the left, you&#;ll see Nylon 6 and on the right, you&#;ll see Nylon 6.6 for comparison.

NYLON 6

NYLON 6.6

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 color

Also easy to color

If you need additional assistance with choosing Nylon 6.6, Nylon 6, or another industrial sewing thread or yarn, we welcome you to reach out to us at Service Thread. We are dedicated to helping our customers understand the characteristics and benefits of nylon as well as all industrial sewing materials.

Nylon 6 vs 66

SIMILARITIES, DIFFERENCES & APPLICATIONS

Many customers ask about the differences between Nylon 6 and Nylon 6/6, and which resin may be best suited for an application. This document will provide some general similarities, differences, and applications for Nylon 6 and Nylon 6/6. While both Nylon 6 and Nylon 6/6 are made of the same elements, they are created from different monomers which leads to the differences in their physical properties.

Similarities

Nylon 6 and Nylon 6/6 are both semi-crystalline polymers and contain the same elements of carbon, hydrogen, oxygen, and nitrogen. The polyamide chains of both nylons are also held together with hydrogen bonds. Due to their similar structures, the polymers possess comparable mechanical qualities regarding tensile and impact strength, elasticity, density, and moisture absorption. As a result, they can be used in many of the same applications such as textiles, consumer goods and automotive parts.

Differences

While the chemical properties of Nylon 6 and 6/6 are similar, there are differences that may help make decisions on which resin to use. Nylon 6 is synthesized via ring&#;opening polymerization with caprolactam, whereas Nylon 6/6 is made through a polycondensation reaction between hexamethylenediamine and adipic acid. Since Nylon 6 is an open structure and its hydrogen bonds are further apart than Nylon 6/6, it results in a lower strength and temperature resistance with a melting temperature of around 220°C. Nylon 6&#;s density is also slightly lower than Nylon 6/6. However, Nylon 6 is better than Nylon 6/6 for toughness and surface appearance.

Nylon 6/6 has greater strength and higher temperature resistance, with a melting point near 260°C, due to a tighter crystal structure with less openings and closer hydrogen bond alignment. It has higher stiffness and lower moisture absorption than Nylon 6.

The chemical resistance of both Nylon 6 and Nylon 6/6 is similar with only strong acids being of major concern. Both Nylon 6 and Nylon 6/6 absorb moisture. This moisture absorption has a plasticizing effect on the products. The strength properties are reduced about 25%, while the impact performance is improved by about the same 25%. Nylon 6 has about 20% greater moisture absorption than Nylon 6/6. So Nylon 6 is on the higher end of the property change, while Nylon 6/6 is on the lower end of the property change.

See below for a comparison of properties for unfilled and 33% glass reinforced Nylon 6 and Nylon 6/6.

Property

Units

Nylon 6/6

Nylon 6

Water Absorption at Equilibrium (23C, 50% RH)

2.80

3.00

Melting Point

°C

260

220

Property (DAM)

Units

With competitive price and timely delivery, sft sincerely hope to be your supplier and partner.

Additional reading:
4 Tips to Select the Perfect Stainless Steel Corrugated ...

Nylon 66 Non-reinforced

Nylon 6 Non-reinforced

Specific Gravity

1.14

Tensile Strength

MPa

Elongation at Break

Flexural Modulus

MPa

3,000

2,800

Notched Izod Impact

kJ/m2

6.0

7.0

HDT at 1.8 MPa

°C

Property (DAM)

Units

Nylon 66 33% glass reinforced

Nylon 6 33% glass reinforced

Specific Gravity

1.38

1.37

Tensile Strength

MPa

200

190

Elongation at Break

2.5

3.0

Flexural Modulus

MPa

9,500

9,400

Notched Izod Impact

kJ/m2

HDT at 1.8 MPa

°C

235

195

Applications

Nylon 6 possesses a more resin rich surface appearance than Nylon 6/6, which works well in products that require good surface aesthetics and do not require higher heat and wear resistance. This may include items such as automotive door handles and roof racks where the appearance of the part is critical. Nylon 6 is also well suited for applications such as office furniture and firearm parts because of its superior surface appearance and higher impact performance.

Nylon 6/6 is preferred for under-the-hood automotive parts such as cylinder head covers and cooling system components, where higher temperatures are of concern. Nylon 6/6 is often used in molding parts such as fasteners and cable ties; in this case, added strength is a benefit. Additionally, those applications are typically impact modified, and the Nylon 6/6 has a higher affinity. In cooling systems, Nylon 6/6 is preferred due to the lower moisture absorption and associated property change.

In the end, Nylon 6 and Nylon 6/6 can often be interchangeable in many applications. But when the application details are examined closely one of them will stand out as the better choice.

Are you interested in learning more about nylon 6 yarn? Contact us today to secure an expert consultation!

Comments

All Comments (0)