Nylon sewing thread and bonded nylon thread possess excellent corrosion and abrasion resistance, primarily due to their unique molecular structure and chemical properties.

I. Reasons for Excellent Abrasion Resistance (Wear Resistance)‌

Abrasion resistance is one of the most outstanding advantages of nylon sewing thread & bonded nylon thread, even surpassing many metal materials. This is mainly thanks to the following points:

1. High Toughness and Self-Lubricity
● Molecular Chain Structure:‌ The molecular backbone of nylon (polyamide) contains regular amide groups (-CO-NH-), but the molecular chains themselves are relatively flexible. This combination of rigidity and flexibility prevents it from easily chipping or peeling under friction, unlike some brittle materials.
● Low Friction Coefficient:‌ The forces between nylon molecular chains are moderate, resulting in a relatively smooth surface. When friction occurs with other surfaces, it can form a very thin transfer film, acting as a self-lubricant, thereby effectively reducing friction resistance and wear. This results in minimal wear loss for nylon thread during repeated friction.

2. High Mechanical Strength and Toughness‌

Nylon has high tensile strength, impact resistance, and resilience. When subjected to friction and compression, it can absorb and disperse stress through minor deformation, rather than being "worn away" forcibly. This characteristic of "using softness to overcome hardness" makes it very durable.

3. Surface Smoothness‌

High-quality nylon thread undergoes precision drawing and surface treatment during production, resulting in a very smooth and flat surface. A smooth surface reduces the actual contact area and mechanical interlocking with contacting objects, thus lowering wear.

In summary, the wear resistance of nylon thread is the result of the synergistic effect of high strength, high toughness, and self-lubricity. It is not the hardest material, but it is "resilient" and "lubricates itself," making it particularly wear-resistant.

II. Reasons for Corrosion Resistance (Chemical Stability)‌

Here, "corrosion resistance" needs to be understood correctly: Nylon has excellent resistance to most common organic solvents and oils, but it is relatively sensitive to strong acids, strong alkalis, and UV light. Therefore, we examine this in two parts:

PART A: The Corrosion-Resistant Side (Resistance to Organic Substances and Some Chemicals):‌

1. Stable Molecular Backbone and High Crystallinity‌

● The molecular backbone of nylon is composed of strong covalent bonds, making it chemically stable. Furthermore, nylon is a semi-crystalline polymer. The well-ordered crystalline regions within its structure are very dense, effectively blocking the penetration and damage from chemical media.

● This dense structure makes it difficult for oils, greases, hydrocarbon solvents, and most alcohols to penetrate the material and cause reactions or swelling. Therefore, nylon thread performs stably in environments like engine oil, gasoline, and lubricating oil, and does not age and swell as easily as rubber.

2. Stability of the Amide Group‌

At room temperature, the amide group is relatively stable against many chemicals, especially in non-polar organic solvents.

PART B: The Non-Corrosion-Resistant Side (Its Chemical Weaknesses):‌

1. Sensitivity to Strong Acids‌

The amide group (-CO-NH-) undergoes hydrolysis in strong acids (e.g., concentrated sulfuric acid, hydrochloric acid) and under high-temperature acidic conditions, leading to molecular chain scission. This severely damages the molecular structure of nylon, causing a sharp decrease in its strength.

2. Sensitivity to Strong Alkalis‌

Although its alkali resistance is slightly better than its acid resistance, strong alkalis (e.g., concentrated sodium hydroxide solution) can also cause hydrolysis of nylon at high temperatures, leading to degradation.

3. Sensitivity to Ultraviolet Light (Photo-oxidation)‌

Under prolonged exposure to UV light in sunlight, the amide groups and methylene groups (-CH2-) in the nylon molecule can undergo photo-oxidative degradation, causing chain scission. This results in embrittlement, yellowing, and reduced strength of the material. This is the main reason for the aging of nylon during long-term outdoor use.

4. Moisture Absorbance‌

The amide group is a polar group with an affinity for water molecules, so nylon has a certain degree of water absorption. Absorbed water causes it to swell and slightly reduces its mechanical strength (though it may increase toughness). While water at room temperature does not rapidly hydrolyze nylon, in high-temperature and high-humidity environments, it can accelerate its hydrolytic aging.

Therefore, in practical applications, the excellent abrasion resistance of nylon sewing thread & bonded nylon thread and its stability against common organic substances make it a very reliable and durable material. However, when used in environments with strong acids, strong alkalis, or long-term outdoor exposure, its chemical weaknesses must be considered, or specially modified nylon products (e.g., with added UV stabilizers) should be selected.

 Nylon Sewing Thread     Bonded Nylon Thread     Filament High Tenacity     Polyamide 6.6 Bonded Thread    PA66 Bonded Thread   PA6.6   Nylon 6,6