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What is the difference between nylon rope 66 and nylon 6

In 1935, Dr. Carothers and his team developed polyamide, commonly known as “nylon”. There are several varieties of nylon, and the most widely used polyamide in commerce is nylon 66 and nylon 6.

Nylon rope 6 is made by polymerizing caprolactam as monomer raw material, while nylon 66 is made by polymerizing ethylenediamine and adipic acid as monomer raw material.

Molecular structure of nylon rope 6 and nylon 66

In terms of molecular structure, both have the same ratio of carbon, hydrogen, oxygen and nitrogen atoms, but Nylon 6 monomeric caprolactam, is polymerized into a polyamide by head-to-tail ring opening, while nylon 66 is formed by alternating hexamethylene diamine and adipic acid to form a polyamide. The differences in monomeric raw materials result in their different polymer structures and physical properties.

1.Different structure

Nylon is a semi-crystalline polymer. nylon 66 has a different hydrogen bonding arrangement than nylon 6. nylon 66 has a more regular arrangement of atoms than nylon 6. The tighter the hydrogen bonding arrangement, the higher the crystallinity. Nylon 6 hydrogen bonds have two arrangements, about 50% of which have longer and weaker tilted hydrogen bonds. Nylon 66 has only one hydrogen bonding arrangement with hydrogen bonds arranged in direct rows, which can form a strong dense polymer structure.

2. Different performance

Structure determines performance. Because the molecular chain arrangement of nylon 66 is different from that of nylon 6, the two have different properties. Under similar process conditions, nylon 66 is more crystalline and more orderly than nylon 6, thus nylon 66 has a higher melting point (its melting point is 40°C higher than nylon 6), slower permeability, stronger resistance to deformation, etc.

Widely used in static rope, kinetic rope, climbing rope, tire cord, textile products, outdoor equipment, guitar strings, etc.

(1) High melting point – high temperature resistance advantage

Unlike polypropylene, both nylons are not easily melted in the case of frictional heat generation. The melting point of nylon 66 is higher than that of nylon 6, which significantly improves the safety factor of recovering from contact with hot objects and also brings friction resistance.

(2) Dimensional stability – Texture retention advantage

Both nylons have superior recovery properties in carpet compared to polypropylene and polyester. However, nylon 66, with its more orderly arrangement and stronger average hydrogen bonding, offers better performance than carpets of the same structure made with nylon 6.

(3) Tighter and more orderly structure – lower stain penetration advantage

Nylon 66 has a more compact and orderly polymer structure that is less permeable than nylon 6, impeding stain penetration. Lower permeability means that stains penetrate nylon 66 more slowly.

Both nylon rope 6 and nylon rope 66 polymer types can be recycled. Manufacturers choose different methods of recycling for certain reasons, and it is up to the manufacturer to assess the environmental impact of their chosen method.

When nylon ropes can last longer and look good, they will last like new and their service life can be extended. Long-lasting products can be replaced less often and with less waste, thus providing better environmental benefits, i.e., more environmentally friendly!

Our kinetic reocovery rope is made from high quality nylon 66,not cheaper nylon 6. which help us to make the high performance recovery rope. To make a safer and smarter solution to our customers.

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