What is EVA interlayer film? What types and applications does it have?

Taking the performance table of Shengding's EVA interlayer film as an example:

In Optical Performance, a lower "Haze" value (e.g., 0.36%) indicates clearer material; a high "Visible Light Transmittance" (e.g., 90.5%) represents good transparency; a low "UV Light Transmittance" helps protect internal items from fading.

In Physical Performance, "Crosslink Degree" (e.g., 76%) reflects the degree of three-dimensional network structure formed after the material is heated and cured—a higher degree indicates better heat resistance and creep resistance; "180° Peel Strength" (e.g., 71.1 N/cm) directly measures its adhesion to glass.

Durability Performance is key. For instance, "no bubbles after boiling for 2 hours" proves its resistance to high temperature and humidity; "no delamination defects after 1000 hours at high temperature and high humidity" indicates its long-term reliability; the extremely low Yellowing Index (YI < 0.5) after "UV Radiation Resistance" demonstrates its outstanding resistance to UV aging. These indicators collectively ensure the safety, aesthetics, and durability of EVA laminated glass during long-term outdoor use.

Although both TPU interlayer film and traditional Polyvinyl Butyral (PVB) interlayer film belong to the category of safety glass interlayer materials, their performance differs significantly:

1. Mechanical Properties: TPU generally has higher tensile strength, tear strength, and elongation at break than PVB, with particularly outstanding toughness (elasticity), offering better impact resistance and energy absorption capacity.

2. Weather Resistance: TPU has excellent resistance to UV aging and damp heat, making it less prone to yellowing, bubbling, or delamination over long-term use, resulting in a longer lifespan.

3. Temperature Adaptability: The glass transition temperature (Tg) of TPU can be as low as -68°C, allowing it to remain flexible in extremely cold environments, whereas PVB becomes hard and brittle at low temperatures.

4. Optical Performance: High-end optical-grade TPU can achieve extreme levels of light transmittance and purity, with very low haze and minimal optical distortion.

5. Processability: TPU is not sensitive to moisture and does not require the strict dehumidification environment and pre-pressing procedures necessary for PVB.

Therefore, TPU is the preferred choice for higher-end and more demanding application scenarios (e.g., aviation, bulletproof), while PVB is more widely used in ordinary architectural and automotive windshield glass.

Shengding has built a whole-process quality control system from "source" to "shipment."

At the raw material end, core raw materials such as high-end polyols, isocyanates, and special additives are sourced from renowned domestic and international suppliers, subject to strict incoming inspection.

At the production end, advanced automated production lines and precise process control systems (e.g., closed-loop control of temperature, pressure, tension) are employed to ensure stable production processes.

At the testing end, the company is equipped with a comprehensive material testing laboratory capable of conducting full-range tests on product optical properties (transmittance, haze), mechanical properties (tensile, tear, adhesion), thermal properties (glass transition temperature), and weather resistance (UV, damp heat, high/low temperature cycling). All tests are conducted according to national standards, national military standards, or customer-specified standards.

At the system end, the strict implementation of management systems like ISO9001 ensures standardized quality management and continuous improvement capabilities.

The company's contributions in the aerospace field are systematic and landmark.

At the product level, its developed aviation-grade TPU interlayer films like SD570 have been successfully applied to windshields, canopies, and cabin windows of various aircraft models. The long-term reliability of the materials under extreme high/low temperatures, UV radiation, and humid-hot environments has been rigorously verified, providing fundamental material assurance for flight safety.

At the standardization level, as the host drafting unit, the company led the formulation of the national standard "General Technical Specification for Aerospace Thermoplastic Polyurethane Elastomer Interlayer Films." This filled a domestic gap in this field, standardized and elevated the industry's technical level, and holds significant importance for ensuring the independent controllability of China's aviation equipment.

At the technology leadership level, through continuous R&D, the company promotes the exploration of TPU material applications in lighter, higher-transparency, and more intelligent (e.g., electrochromic) aircraft transparencies.

Shengding adheres to a market strategy of "rooted domestically, with a global perspective." In the domestic market, the company's products are deeply integrated into the supply chains of national pillar industries and strategic emerging industries such as aerospace, rail transportation, automotive manufacturing, security protection, and high-end building materials, and have established stable cooperative relationships with numerous industry leaders.

In the international market, relying on superior product quality and technical strength, the company has successfully exported its products to multiple countries and regions including North America (USA), South America (Brazil), Europe (Russia), the Middle East (Iran), and Southeast Asia (Singapore, India), gaining recognition from international clients.

The company actively expands its global business by participating in international industry exhibitions and establishing overseas technical service networks, striving to become a significant supplier in the global high-performance polymer materials field and allowing high-end "Made-in-China" materials to serve the world.

Shengding offers a wide variety of TPU granules (pellets), with over 60 product grades covering a broad Shore hardness range from soft 80A to rigid 70D. These granules possess a series of outstanding comprehensive properties: High transparency, suitable for products with appearance requirements; Excellent mechanical properties, including high tensile strength, high tear strength, and extremely high elongation at break, providing products with good elasticity and durability; Outstanding chemical resistance, able to withstand oils, greases, and various chemicals; Good hydrolysis resistance and a wide processing temperature window, suitable for various processing techniques such as injection molding, extrusion, and blow molding.

Based on these characteristics, Shengding TPU granules are widely used in multiple fields including automotive components (e.g., dust covers, pipes), wire and cable sheathing, industrial transmission parts, sports equipment, medical devices, and 3D printing materials, providing key material support for customer product upgrades and innovation.