The Unique Challenge of Synthetic Leather Antifungal Treatment: Completely Different Substrate Chemical Environments
Many factories habitually apply antifungal experiences from genuine leather or natural fibers to synthetic leather, often with limited success. The root cause lies in the substrate of synthetic leather—polyurethane (PU) or polyvinyl chloride (PVC)—whose chemical composition is fundamentally different from the collagen fibers of genuine leather. The mold nutrient sources in genuine leather primarily come from residual oils and proteins, whereas mold growth in synthetic leather is closely related to plasticizers, stabilizers, fillers, and processing aids in the resin. These components migrate to the surface under specific temperature and humidity conditions, forming carbon and nitrogen sources directly usable by mold. In other words, the “food” for mold on synthetic leather is not the protein of the leather itself, but the additives in the polymer material.
Selection Logic for Synthetic Leather Antifungal Agents: Shifting from “Surface Protection” to “Internal Inhibition”
Since mold growth in synthetic leather often begins with the migration of internal additives, relying solely on surface spraying of antifungal agents is insufficient to eradicate the problem. Therefore, synthetic leather antifungal treatment requires a dual strategy of “internal addition + post-treatment.” Internal addition antifungal agents (such as iHeir-907) should be incorporated during the wet or dry coating process of synthetic leather. Their active ingredients can be uniformly dispersed in the polyurethane resin, continuously inhibiting microbial reproduction within. The mechanism of iHeir-907 involves disrupting the respiratory chain and energy metabolism of mold cells, rather than simple contact killing, thus remaining effective even during additive migration. Post-treatment targets potential contamination and residual nutrient sources on the surface of finished synthetic leather. Non-release antifungal agents (such as iHeir-3) can be applied via spraying or dipping, forming a physical barrier on the surface to prevent the attachment and germination of external mold spores.
Process Parameters for Synthetic Leather Antifungal Treatment: Precise Control of Concentration, Temperature, and Time
The success of synthetic leather antifungal treatment often depends on the rationality of parameter settings. Below are recommended parameters based on extensive factory testing:
- Internal Addition (iHeir-907): Recommended addition amount is 0.5%-1.5% of the resin solid content. Mixing time should be ≥15 minutes to ensure uniform dispersion. Processing temperature should be controlled between 80-120°C to avoid decomposition of the antifungal agent due to high temperatures.
- Surface Treatment (iHeir-3): For spraying, the dilution ratio is 1:10-1:20 (iHeir-3:water), with a spray volume of 15-25 g/m². For dipping, immersion time is 15-30 seconds, drying temperature is 80-100°C, ensuring moisture content drops below 8%.
Special attention: If there are release paper residues or mold release agents on the synthetic leather surface, they will significantly affect the adhesion of the antifungal agent. It is recommended to wipe with alcohol or a specialized cleaning agent during the pretreatment stage.
Overlooked Blind Spots in Synthetic Leather Antifungal Treatment: Plasticizer Migration and Temperature-Humidity Coupling Effects
Two technical blind spots most easily overlooked in synthetic leather antifungal treatment: First, the accelerating effect of plasticizer migration. When ambient temperature exceeds 40°C, the migration rate of phthalate plasticizers in PVC synthetic leather can increase by 3-5 times. These migrants form an oil film on the surface, becoming a “breeding ground” for mold. Second, the temperature-humidity coupling effect. Although synthetic leather has lower hygroscopicity than genuine leather, its surface microporous structure still adsorbs moisture when relative humidity >85%, forming localized high-nutrient microenvironments with migrated plasticizers. Our tests found that under simulated maritime conditions at 35°C and 90% humidity, untreated synthetic leather samples showed visible mold spots within 72 hours, while samples treated with iHeir-907 internal addition and iHeir-3 surface treatment showed no significant changes under the same conditions for 120 hours.
Conclusion: Synthetic Leather Antifungal Treatment Requires a “Material-Process-Environment” Tripartite Solution
iHeir-907 internally inhibits nutrient sources from additive migration, while iHeir-3 forms an impermeable protective layer on the surface. They act on different stages of synthetic leather antifungal treatment, creating a synergistic system of “internal inhibition and external prevention.” No single measure can cover the full-cycle risks from production to storage of synthetic leather. For customized solutions tailored to specific synthetic leather types (PU or PVC) and processing methods (dry or wet), contact technical consultants for free samples for targeted testing.