Study Reveals Causes Fixes for TPE Elastomer Odor Problems

"The new TPE yoga mat still has a strange smell after several days of airing out - is this normal? Could it be harmful to health?" Consumers are increasingly concerned about odor issues in TPE (thermoplastic elastomer) products. This article provides a comprehensive examination of the sources of odor in TPE elastomer products and offers systematic solutions to help manufacturers improve product quality and ensure consumer safety.

TPE, or thermoplastic elastomer, is a novel material that combines the high elasticity, strength, and resilience of rubber with the plasticity of plastic. TPE materials feature soft texture, good weather resistance, and typically contain no plasticizers, making them considered environmentally friendly and non-toxic. With a wide hardness range, excellent coloring properties, comfortable touch, outstanding weather, fatigue and temperature resistance, superior processing performance that requires no vulcanization, and recyclability that reduces costs, TPE is widely used in daily products that come into contact with human skin, such as toys, tableware, sports equipment, and medical devices.

As a blended polymer material, TPE's formulation system often contains various oils (such as white oil, naphthenic oil, etc.). These oil components primarily consist of organic hydrocarbon compounds that easily volatilize at high temperatures, making them one of the main causes of odor in TPE products. Moreover, oil quality directly affects odor intensity, with inferior oils typically producing stronger smells.

Beyond oils, other additives in the formulation may also contribute to odor. The type and quantity of additives both influence the final product's smell. Generally, fewer additives result in less odor. Below is a deeper analysis of primary odor sources:

Softening oils are crucial components in TPE formulations, primarily serving to reduce material hardness while improving processing performance and product flexibility. However, being low-molecular-weight substances, softening oils tend to volatilize during processing or at elevated temperatures, releasing small molecules that generate odor. Notably, low-hardness (0-30A) TPE products typically emit stronger odors than high-hardness (70-100A) ones, as they require more softening oil.

Softening oils vary significantly by type and composition:

• Paraffinic oils: Offer good chemical and thermal stability but relatively stronger odor.
• Naphthenic oils: Feature excellent solubility and compatibility with lighter odor.
• Aromatic oils: Have good solubility but contain harmful substances like polycyclic aromatic hydrocarbons, producing strong odors and being environmentally unfriendly - their use should be avoided.
• Synthetic oils: Manufactured through chemical synthesis, they offer superior performance with minimal odor, though at higher cost.

Beyond softening oils, TPE formulations contain various other components including base resins, compatibilizers, stabilizers, fillers, and colorants. The selection of these materials also affects the final product's odor. Therefore, components with minimal odor should be prioritized, and their quantities carefully controlled.

TPE processing methods significantly influence final product odor. During high-temperature processing, softening oils and other components volatilize more rapidly, increasing odor. Thus, processing temperatures should be minimized, duration shortened, and ventilation enhanced to reduce odor generation.

To address odor issues in TPE products, comprehensive measures should be implemented across multiple aspects:

• Select low-odor softening oils like highly refined naphthenic or synthetic oils
• Choose other formulation components with minimal odor profiles
• Minimize additive quantities while maintaining performance requirements

• Adjust softening oil types and quantities according to hardness requirements
• Incorporate odor absorbers like activated carbon or zeolite
• Consider bio-based or biodegradable TPE alternatives

• Optimize processing temperatures to minimum effective levels
• Reduce high-temperature exposure duration
• Enhance workshop ventilation systems
• Implement post-production treatments like extended airing

• Increase surface area for better odor dissipation
• Implement multilayer structures with low-odor surface layers

• Establish comprehensive quality management systems
• Conduct specialized odor testing for sensitive applications
• Collaborate with suppliers on low-odor material development

A prominent sports brand successfully reduced odors in its new yoga mat line by implementing these solutions - selecting high-quality low-odor softening oils, optimizing formulations, and strictly controlling production processes. This significantly improved product acceptance and market competitiveness.

Addressing odor in TPE products requires a systematic approach encompassing material selection, formulation optimization, process control, product design, and quality management. Only through comprehensive measures can manufacturers effectively reduce odors, enhance product quality, and meet consumer demands for health and environmental safety. As technology advances, new generations of eco-friendly, low-odor TPE materials will emerge, expanding options across industries.

It's important to note that even "odor-free" TPE may emit some smell during high-temperature molding due to softening oil volatilization, which is normal. Typically, odors diminish as products cool and small molecules dissipate. Therefore, TPE product odor assessment should consider application scenarios and usage conditions.