TPU Industry FAQ | Common Questions & Answers

TPU, or thermoplastic polyurethane, is a versatile and durable elastomeric material known for its flexibility, high tensile strength, abrasion resistance, and chemical stability. It is widely used in industries such as medical, automotive, electronics, and textiles.Role of TPU in hot melt adhesive films:Adhesion enhancer: TPU provides excellent bonding to various substrates, including fabrics, plastics, and metals, ensuring durable adhesion.Flexibility and elasticity: TPU ensures the adhesive film remains flexible, allowing for bending, stretching, and conforming to irregular surfaces without cracking.Durability: TPU enhances resistance to wear, tear, and environmental factors such as heat, moisture, and chemicals, extending the life of the adhesive bond.Transparency and aesthetics: TPU hot melt adhesive films can maintain high clarity, making them suitable for applications where visual quality is important.Overall, TPU is a key component in hot melt adhesive films, combining strong adhesion, flexibility, and durability to meet high-performance requirements across diverse applications.

TPU, or thermoplastic polyurethane, is a flexible and durable material that can be effectively combined with carbon fiber to create high-performance composite materials. This combination leverages the unique properties of both TPU and carbon fiber, making it suitable for automotive, aerospace, electronics, and sports equipment applications.Key points on combining TPU with carbon fiber:Matrix and reinforcement: TPU acts as the matrix, providing elasticity and impact resistance, while carbon fiber serves as the reinforcement, adding strength, stiffness, and dimensional stability.Processing methods: TPU and carbon fiber can be combined using techniques such as hot pressing, extrusion, or injection molding. Proper temperature and pressure control ensure uniform bonding and prevent fiber damage.Surface treatment: Carbon fibers may undergo surface treatments or sizing to improve adhesion to TPU, enhancing mechanical performance and durability of the composite.Applications: TPU-carbon fiber composites offer lightweight, strong, and flexible materials ideal for protective gear, structural components, and flexible electronic housings.By combining TPU with carbon fiber, manufacturers can create composites that balance strength, flexibility, and lightweight performance, meeting high standards in demanding applications.

Corona treatment is an electrical surface modification process that increases the surface energy of materials, improving adhesion for subsequent coatings, printing, or laminating. How corona treatment works on TPU films: High-voltage discharge: A high-frequency, high-voltage power supply is applied between a metal electrode and the corona treatment roller, generating electrical discharge. Air ionization and ozone formation: The discharge ionizes the surrounding air, producing ozone and energetic particles that interact with the TPU surface. Surface activation: High-energy electrical sparks impact the TPU film, creating a micro-roughened, chemically active surface, which increases surface energy and improves adhesion. Applying corona treatment to TPU films significantly enhances surface adhesion. It allows for stronger bonding when applying adhesives, coatings, or double-sided tapes, and improves durability and water resistance. It is important to apply coatings only on the corona-treated side of the TPU film for optimal adhesion and performance. Overall, corona treatment is a reliable and widely used method to prepare TPU film surfaces for printing, laminating, and coating applications, ensuring better product quality and performance.

Two-layer TPU and PET composite films are made by laminating a PET film onto a TPU film using roller pressing and winding techniques. This combination leverages the advantages of both TPU and PET materials. Advantages of TPU and PET composite films include: Elasticity: The two-layer structure provides excellent flexibility, allowing the film to maintain shape during printing and processing without distortion or contamination. Processing convenience: The composite film is easy to handle and can be readily used in printing, coating, and laminating processes. High-end applications: Widely used in advanced electronics and optical fields, offering good optical performance and protection for delicate surfaces. In addition to two-layer TPU-PET films, we also produce three-layer PET-TPU-PET composite films to meet specific application requirements, providing enhanced mechanical strength, protection, and stability. Overall, TPU-PET composite films combine the softness and elasticity of TPU with the strength, stability, and optical clarity of PET, making them ideal for demanding industrial and electronic applications.

TPU films are typically supplied in rolls with standard widths such as 1.37 m and 1.53 m. However, these standard sizes do not always meet specific customer requirements. To achieve the desired size, slitting is necessary to convert the original roll into materials that match the required dimensions. Slitting is the process of converting TPU film materials that do not meet the required dimensions into suitable ones using specialized slitting equipment. This step is often part of a production sequence that includes slitting, printing or coating, laminating, and further slitting to prepare the final product. Common TPU film slitting methods include: Edge trimming: Removes the process edge material left from previous production steps, commonly used in the processing of laminated films and similar materials. Slitting: Converts wide rolls into multiple narrower rolls to obtain the required width specifications. Rewinding: Divides large-diameter rolls into several smaller rolls. Proper slitting and rewinding help ensure good appearance and stable winding quality of the final product. The main purposes of slitting TPU films are: To correct appearance defects such as misalignment or uneven winding, improving the overall quality grade of the product. To re-inspect the entire length of the film during slitting and remove defective sections, ensuring consistent quality. Regardless of the slitting method used, the processed film must meet the required dimensional specifications — including width, length, and quality parameters such as flatness, appearance, and winding condition — to ensure optimal performance in downstream applications.

The melting point of thermoplastic polyurethane refers to the temperature at which the material transitions from a solid to a molten state, expressed in degrees Celsius ℃. Several factors influence the melting point of thermoplastic polyurethane materials:Hard segment content: Higher hard segment content results in a higher melting point.Molecular weight: For materials with the same hard segment content, a higher molecular weight leads to a higher melting point.Hard segment composition: Different raw materials in the hard segment can cause variations in the melting point.The melting point is tested under constant pressure by measuring the temperature at which thermoplastic polyurethane transitions from a solid to a molten state. This measurement reflects the thermodynamic performance of the material.Understanding these factors helps manufacturers select the right thermoplastic polyurethane for applications such as hot melt adhesive films, ensuring optimal performance in both processing and end-use conditions.

Thermoplastic polyurethane film is a strong, durable, and flexible elastomer known for its excellent wear resistance, high strength, toughness, chemical resistance, hydrolysis resistance, mold resistance, low-temperature flexibility, transparency, and color stability. TPU processing is highly versatile, allowing it to be used in various applications.TPU films are widely recognized for their waterproof and breathable properties, often referred to as "breathable waterproofing." They are commonly used in outdoor apparel such as mountaineering jackets, windbreakers, hoodies, and seamless undergarments. TPU-based composite fabrics provide comfort and breathability, keeping wearers cool even in hot summer conditions.TPU films can resist liquid penetration while allowing high water vapor permeability. This is achieved thanks to their special molecular structure. TPU films are non-porous hydrophilic membranes that use hydrophilic groups to transport water molecules from the side with higher vapor pressure to the side with lower vapor pressure. As a result, TPU films are both waterproof and breathable, providing excellent moisture management.The high elasticity of TPU films ensures a close fit to the body, adapting well to different surfaces while maintaining comfort. Their breathability allows the skin to "breathe," reducing the risk of irritation or allergies.

Thermoplastic polyurethane (TPU) is a linear block copolymer composed of soft segments from polyols and hard segments from diisocyanates and chain extenders. TPU can be classified into polyester-based and ether-based types. Here are reliable methods to identify them: Physical Methods: Density Test: Measure the density of the TPU sample. Ether-based TPU typically ranges from 1.13 to 1.18 g/cm³, while polyester-based TPU ranges from 1.18 to 1.22 g/cm³. Tear Test: Tear the TPU film. If the resulting tear has obvious jagged edges, it is polyester-based TPU. If the jagged edges are minimal, it is ether-based TPU. Chemical Methods: Colorimetric Reaction Method 1: Dissolve the TPU sample in 5–10 mL of glacial acetic acid. If insoluble, use other solvents such as dimethylformamide (DMF) or o-cresol. Drop the solution into approximately 0.1 g of p-aminobenzaldehyde reagent. Polyester-based TPU will develop a yellow color within a few minutes. Ether-based TPU does not show this reaction. Colorimetric Reaction Method 2: Mix about 5 g of TPU with phenolphthalein in methanol and add a few drops of 2 M potassium hydroxide. Then add a few drops of hydroxylamine hydrochloride saturated solution in methanol. Heat to 50°C briefly, acidify with 1 M hydrochloric acid, and add one drop of 3% ferric chloride solution. Polyester-based TPU will immediately display a purple or reddish-purple color, while ether-based TPU shows no color change. Physical methods are simple and easy to perform, while chemical methods are more complex but provide higher accuracy. Choose the method that best suits your available resources.

TPU films are widely used for printing due to their excellent properties — abrasion resistance, flexibility, corrosion resistance, and aging resistance. However, many people face challenges when printing on TPU surfaces. To achieve optimal results, it’s essential to follow these four core principles: Choose the right ink: Use polyurethane-based inks (PU or TPU ink) as they are chemically compatible with TPU materials, ensuring strong adhesion and durability. Perform corona treatment: Treat the TPU film surface with corona discharge to increase its surface energy to above 38 dynes — ideally between 40 and 42 — for better ink adhesion. Apply chemical surface treatment: Wipe or coat the surface with chemical solvents to further enhance printability. The effectiveness ranking of common solvents is: DMF > MEK > Toluene > Ethyl acetate > Thinner > Alcohol. Choose the right surface texture: Matte or frosted TPU films provide better ink adhesion and higher color fastness compared to glossy surfaces due to their larger surface area. By mastering these four principles, printing on TPU films becomes straightforward and worry-free.

No, polyester-based TPU and polyether-based TPU cannot be directly blended or processed together. This is mainly due to differences in their molecular structure and compatibility.Key reasons:Delamination risk: Different polarity (ether vs. ester groups) causes poor compatibility, leading to visible layering and haziness.Poor miscibility: Molecular interactions and crystallinity differ significantly, resulting in weak bonding.Physical property loss: Even if processed together, the final product shows a major decline in mechanical and transparency performance.Exception case: Polyether TPU synthesized with PTMG has slightly better compatibility, but still not recommended for production use.Conclusion: Polyester TPU and polyether TPU should not be mixed during processing, especially for transparent or high-performance applications.