leather mold prevention: Essential Anti-Mold Secrets

Causes of leather mold

The raw hides used in leather production are rich in protein, fat, and other nutrients, making them highly susceptible to microbial invasion during storage. Processed finished leather Although resistance to microorganisms increases, mold still occurs, especially when large amounts of fat-adding agents made from natural oils are introduced during leather production, which also serve as breeding grounds for microorganisms. Additionally, the porous and polar structure of leather makes it easily absorbent, making leather acidic. All of the above causes form the basic conditions for mold.

Moldy leather products may develop white, blue, yellow, and black colonies or color spots, with surface mold spreading into the leather, affecting the leather’s wear resistance, strength, and elasticity.

Common mold

Common molds include Aspergillus, Penicillium, Trichoderma, Mucor, and Rhizopodium.

Aspergillus

Aspergillus includes many species, mainly Aspergillus flavus, Aspergillus parasiticus, Aspergillus variegum, Aspergillus nest-going, and others. It is a genus of bacteria capable of producing biological toxins, with aflatoxins produced by Aspergillus flavus and Aspergillus parasitic being particularly notorious.

Penicillium

The vegetative mycelium of Penicillium appears colorless, monochrome, or vivid, with a septal structure. It is either hidden or partially absent, partially aerial type, with aerial hyphae appearing densely felt or fluffy, or partially free in bundles.

Trichoderma

The Xylella colony initially appears white, dense, and round, spreading outward. Later, green spores emerge from the center of the colony, turning green, surrounded by bands of white mycelium, and eventually the entire colony turns green. Green Trichoderma mycelium is white, slender, 1.5~2.4 microns wide, and produces conidia.

Mucor

Mucor mold has a well-developed mycelium, loose colony texture, cotton-like texture, and is composed of many branched hyphae. The hyphae have no septa and have multiple nuclei. Mucor grows rapidly, with usually white hyphae without rhizoids, belonging to single-celled fungi.

Rhizopodium mold

Rhizopus colonies are loose or dense, initially white, later turning grayish-brown or dark brown. The hyphae crawl colorlessly, with well-developed rhizoids and branches that are finger-like or root-like and brown. The spores are yellow when first appearing and turn black when mature.

Mildew prevention measures for leather

The basic principle of leather mildew prevention is to create an environment inside and outside the leather that is unsuitable for mold growth and reproduction.

Eliminate nutrients

By removing nutrients such as sugars, proteins, and fats left inside and on the leather during the tanning process, it eliminates the foundation for mold growth on the leather.

Control environmental conditions

For example: purifying the air to reduce the number of mold spores; Lowering environmental temperature and humidity and improving leather dryness; Add oxygen scavengers to reduce oxygen content and inhibit mold growth.

Fumigation method

After sealing and packaging leather products, ethylene oxide is applied to penetrate the leather and achieve sterilization. This method ensures that packaged leather products do not develop mold for a considerable period of time, ensuring the products arrive safely at their destination. However, this method requires high safety protection measures, complex process conditions, high costs, and severe air pollution, so it is now rarely used.

Radiation anti-mold method

By utilizing the penetrating and lethal power of Co-Y rays, it eliminates all fungal spores inside the leather, thereby eliminating the internal causes of leather mold. For mildew prevention on leather products, this method is very effective but requires specialized equipment, requires high one-time investment, and to ensure absolute environmental safety, radiation fields are best built in sparsely populated areas, making it difficult to promote and popularize them.

Use anti-mold agents

This is the main method for preventing mold in leather, and its mechanism mainly involves three aspects:

(1) Inhibits protein synthesis and promotes bacterial coagulation;

(2) Inhibiting the synthesis of fungal ergozol and inactivating mold;

(3) Impairs metabolic function, inhibiting spore production or spore germination.