How to Avoid Compromising Flame Retardancy When Storing Flame-Retardant TPE?

Flame-retardant TPE has long been widely used in safety-critical industries such as electronics, automotive, and cables due to its excellent flame retardancy, flexibility, and processability. However, storage conditions directly impact its flame-retardant effectiveness. Improper storage can lead to flame retardant leaching and reduced mechanical properties, threatening the safety of end products. So, what key points should be noted when storing flame-retardant TPE to avoid compromising its flame-retardant properties? This article shares insights from Huizhou Zhongsuowang.

Flame-retardant TPE storage must focus on three core objectives: preventing flame retardant migration, preventing material aging, and resisting external interference. Key points are as follows:

1. Temperature Control: Prevent high temperatures from causing flame retardant migration

Flame retardants in flame-retardant TPE (e.g., halogen-based, phosphorus-based) are prone to thermal migration under high temperatures—migrating from the material's interior to its surface. This reduces local flame retardant concentration, directly compromising flame retardancy. Simultaneously, high temperatures may cause the TPE base material to soften, stick together, and damage its structure. Recommended storage temperature: 15-30°C. Avoid prolonged exposure above 35°C. Keep away from heat sources like radiators, boilers, and ovens. Do not expose to direct sunlight. Avoid high-temperature areas such as vehicle interiors and rooftop warehouses during summer.

2. Humidity Control: Prevent moisture absorption affecting flame retardancy and processing

Certain flame-retardant TPEs, particularly those containing polar groups or using hygroscopic flame retardants, absorb moisture from the air in humid environments. Short-term exposure may cause minor reactions with flame retardants (e.g., hydrolysis of inorganic flame retardants), reducing flame retardancy. Long-term moisture absorption creates microscopic bubbles within the material, leading to defects during subsequent processing (injection molding, extrusion) and indirectly affecting the uniformity of flame retardancy. Maintain relative humidity between 40%-60%. In humid regions, install dehumidifiers in storage areas or employ dual protection for flame-retardant TPE: sealed packaging + desiccants (silica gel or montmorillonite, replaced regularly).

3. Packaging and Sealing: Preventing Flame Retardant Volatilization/Contamination

Packaging for flame-retardant TPE must provide barrier properties and airtight sealing to prevent two critical issues: certain organic flame retardants (e.g., some phosphorus-based or nitrogen-based types) exhibit slight volatility, leading to gradual loss during prolonged open storage; dust, oil residues, or solvent vapors may adhere to material surfaces or penetrate internally, reacting with flame retardants and compromising the flame-retardant system. Packaging must use original containers, typically kraft paper bags lined with PE film, sealed plastic bags, or cardboard boxes. Unused material after opening must be resealed promptly and never left exposed. Non-sealed containers like open drums or uncovered bins are prohibited, as is co-storage with oil contaminants or solvents such as alcohol or gasoline.

4. Light Protection: Prevent UV Accelerated Material Degradation

Ultraviolet radiation, particularly UV rays in sunlight, accelerates the aging and degradation of TPE substrates while potentially disrupting the chemical structure of flame retardants. Substrate aging reduces material flexibility and causes cracking, facilitating the migration of flame retardants through fissures. Flame retardant decomposition directly diminishes their efficacy, preventing materials from achieving intended flame retardancy ratings (e.g., downgrading from V0 to V2). Storage environments should utilize warehouses free from direct natural light or employ opaque, light-blocking packaging such as black PE bags or light-shielding cardboard boxes. Avoid outdoor stacking or proximity to light sources like transparent windows or UV lamps.