1、 Core mechanism: Physical shielding vs. chemical cycling protection (essential differences at the molecular level)
1. Carbon black (physical protection scheme)
Action principle: anti-aging through the dual mechanism of “physical shading+free radical adsorption”. Carbon black particles (particle size 20-50nm) are uniformly dispersed inside the fibers, with a shielding rate of ≥ 99% against 200-400nm UVA/UVB, like a “sunshade inside the fibers”, directly blocking ultraviolet penetration; Meanwhile, the active sites on the surface of carbon black can adsorb a small amount of free radicals, reducing their attack on molecular chains.
Molecular limitations: It can only block external damage caused by ultraviolet radiation and cannot intervene in thermal oxidative aging inside fibers (such as residual free radicals from processing and molecular chain breakage at high temperatures), and has no repair function, belonging to “passive defense”.
2. Hindered amine (HALS, chemical protection scheme)
Action principle: anti-aging through the active chemical mechanism of “free radical cycle capture+molecular chain repair”. HALS molecules (such as HALS-770, HALS-944) do not directly absorb ultraviolet light, but generate nitrogen oxygen radicals (NO ·) under ultraviolet/thermal stimulation, which can cyclically capture reactive free radicals such as R ·, ROO · (one HALS molecule can capture dozens of free radicals); Meanwhile, NO can repair slightly broken molecular chain ends and convert unstable free radicals into stable structures, belonging to the category of “active attack+damage repair”.
Molecular level advantages: It can simultaneously resist photo oxidative and thermal oxidative aging, covering the chain reaction of external damage caused by ultraviolet radiation and internal free radicals, providing more comprehensive protection.
2、 Core Performance Showdown (Quantitative Data Comparison)
Carbon black scheme versus hindered amine (HALS) scheme
UV protection efficiency
✅ Advantages: The short-term UV shielding effect is extremely strong. When the dosage is 2% -5%, the UV penetration rate is ≤ 0.1%, and the initial light aging induction period is long (≥ 600 hours). Limitations: Agglomeration of carbon black (particle size>100nm) can lead to local UV shielding blind spots, and “local brittleness” is prone to occur in the later stages of aging.
✅ Advantages: UV protection without blind spots, indirectly blocking UV induced damage through free radical capture, long-term stable protection; After compounding with UV absorbers, the photo aging induction period can reach over 1000 hours. Limitations: The initial UV shielding effect is weaker than carbon black and requires the use of UV absorbers to achieve the same initial protection.
Long term anti-aging life
❌ Disadvantage: After 3-5 years of outdoor use, carbon black particles are prone to migration and aggregation, and cannot repair molecular chain damage, resulting in a fabric fracture strength retention rate of less than 50%; After 2000 hours of aging, the fracture strength loss of QUV is ≥ 40%. Case: Pure carbon black modified PP non-woven fabric, outdoor geotextile will expire after 4 years of use.
✅ Advantages: HALS can be recycled (regeneration reaction of NO ・→ HALS). After 5-8 years of outdoor use, the anti-aging ingredients still retain more than 60%; After 2000 hours of aging, the retention rate of fracture strength of QUV is ≥ 70%. Case: The PP bird proof net made of HALS+UV-327 compound has an outdoor service life of up to 8 years.
Thermal oxidative aging resistance
❌ Disadvantage: Without antioxidant function, it cannot suppress the thermal oxidative chain reaction inside the fiber in high temperature environments (>60 ℃), and the molecular chain breakage rate is 2-3 times faster than the HALS scheme. >Data: After 500 hours of thermal oxidative aging at 120 ℃, the loss of fracture strength is ≥ 55%.
✅ Advantages: Some HALS (such as HALS-944) also have auxiliary antioxidant functions, can decompose hydrogen peroxide, and inhibit thermal oxidative aging; After 500 hours of thermal oxidative aging at 120 ℃, the loss of fracture strength is ≤ 30%. Synergistic effect: After compounding with hindered phenolic antioxidant (1010), the thermal oxidative aging life is further increased by 30%.
Impact on fabric performance
❌ Disadvantage: When the addition amount is ≥ 3%, the fiber color turns black, which limits the application scenarios; Agglomeration of carbon black can easily lead to fiber defects, resulting in a 15% -20% decrease in elongation at break and a 10% -15% decrease in breathability. Limitations: Cannot be used for light and colored non-woven fabric products.
✅ Advantages: HALS is colorless and transparent, and when added in an amount of 0.2% -0.5%, it does not affect the color and appearance of the fabric; Good compatibility with fibers, with an impact of ≤ 5% on fracture strength, elongation, and breathability. Adaptation: It can be used in scenarios that require appearance, such as light colored sunshade nets and non-woven fabrics for car interiors.
Processing compatibility
❌ Disadvantages: Carbon black has a high density (1.8-2.1 g/cm ³), which differs greatly from PP (0.91 g/cm ³) in density. It is prone to settling and agglomeration during spinning, requiring additional dispersants (such as calcium stearate) and causing significant wear on the screw. Processing requirements: It is necessary to increase the screw speed (≥ 300r/min) to increase energy consumption.
✅ Advantages: HALS is a low melting point solid (melting point 80-120 ℃), with excellent melt compatibility with PP (solubility parameter difference ≤ 0.8), uniform dispersion during spinning, no need for additional dispersants, and no wear on equipment. Processing cost: 10% -15% lower than the carbon black solution (saving dispersants and energy consumption).
Environmental Protection and Safety
✅ Advantages: Carbon black has stable chemical properties, no migration risk, and meets safety standards such as food contact and medical use (such as FDA). Limitations: Some inferior carbon black contains heavy metal impurities, and the purity of the raw materials needs to be strictly controlled.
✅ Advantages: High quality HALS (such as HALS-770) have no VOC emissions, a migration rate of ≤ 0.1%, and comply with environmental standards such as GB 4806 and REACH. Attention: Low molecular weight HALS (molecular weight<2000) are prone to migration, and high molecular weight models (molecular weight ≥ 4000) should be selected.
cost control
✅ Advantages: The price of carbon black raw materials is low (about 5-8 yuan/kg), and when the addition amount is 2% -5%, the unit cost only increases by 0.3-0.6 yuan/square meter, making it suitable for low-cost, large-scale production.
❌ Disadvantage: HALS raw material prices are relatively high (about 80-120 yuan/kg), with an added amount of 0.2% -0.5%+UV absorber 0.3% -0.5%, resulting in an increase in unit cost of 0.8-1.2 yuan/㎡, which is higher than the carbon black solution.
3、 Applicable scenario showdown: Who is better suited to your needs?
1. The “advantageous scenarios” of the carbon black solution
Low cost, black appearance acceptable short-term outdoor scenes: such as ordinary agricultural covering cloth (1-2 seasons of use cycle), temporary construction enclosures (service life ≤ 2 years), the high initial UV shielding rate of carbon black can meet basic protection, and the cost advantage is obvious;
High dust, harsh environmental scenarios: such as mining geotextiles, landfill covers, carbon black has strong physical stability, is not easily affected by pollutants, and black can absorb heat, suitable for insulation scenarios.
2. “Advantage Scenarios” of HALS Solution
Long term outdoor use (≥ 3 years): such as geotextiles (with a lifespan requirement of 5-8 years), bird proof nets, sunshade nets, HALS’s long-term chemical protection can avoid aging and failure in the later stage, reducing replacement costs;
Light colored, colorful, or visually demanding scenarios: such as non-woven fabrics for car interiors, household sunshades, and light colored agricultural greenhouse films. HALS’s colorless and transparent characteristics do not affect the product’s appearance and are suitable for diverse needs;
High temperature and complex environmental scenarios, such as outdoor tents and industrial filter materials (working temperature 40-80 ℃), HALS’s ability to resist thermal oxidative aging can cope with molecular chain damage at high temperatures, ensuring product stability;
Scenarios with high safety and compliance requirements, such as non-woven fabrics for food packaging and medical protective non-woven fabrics, have HALS low migration and residue free characteristics that are more in line with safety standards.
4、 Advanced Choice: Single Solution vs. Composite Solution?
1. Limitations of a single solution
Carbon black solution: only UV resistant, unable to resist thermal oxidative aging, prone to brittleness after long-term use; Single color, limited application;
HALS single solution: The initial UV protection is weak, and it needs to be combined with UV absorbers (such as UV-327) to achieve the best light protection effect.
2. Optimization direction of composite scheme (1+1>2)
Carbon black+HALS composite: For black long-term outdoor products (such as black geotextiles), adding 2% -3% carbon black (strengthening initial UV shielding)+0.2% HALS (inhibiting thermal oxidative aging and free radical proliferation) can extend the outdoor life from 3-5 years to 6-8 years, and increase the retention rate of fracture strength by 20%;
HALS+UV absorber+antioxidant composite: for high demand scenarios (such as car interior, high-end sunshade), the “0.3% HALS+0.4% UV-327+0.2% AO-1010″ composite system is adopted, covering the whole links of photo oxygen and thermal oxygen. The breaking strength retention rate of QUV after aging for 3000 hours is ≥ 65%, which is the most mainstream high-end anti-aging scheme at present.
Post time: Mar-09-2026