Thermoplastic polyurethane (TPU) not only exhibits the rubber-like properties of crosslinked polyurethanes—such as high strength and excellent abrasion resistance—but also possesses the thermoplastic characteristics of linear polymers, thereby extending its applications into the plastics sector. In particular, over the past few decades, TPU has become one of the fastest-growing polymer materials.

TPU film is an important application form of TPU material, and in recent years, with the development and advancement of high technology, its use has become increasingly widespread. However, due to factors such as its difficult processing and product instability, no manufacturers in mainland China have yet achieved reliable mass production.

1 Current Status of Production and Applications of TPU Films

1.1 Analysis of TPU Film Production Status

TPU production is primarily concentrated in the United States, Western Europe, and Japan, with Taiwan also accounting for a notable share. Internationally prominent manufacturers include Bayer, Dow, Mobay, and DuPont. In Taiwan, several influential TPU producers operate, such as Sanhong Chemical, Gaoding Chemical, Risheng Chemical, and DingZing Chemical. TPU film represents an important application of TPU and one of its most promising market segments. Major producers include Germany’s Bayer, Taiwan’s DingZing Chemical, and South Korea’s Jinxing Chemical, with DingZing particularly excelling within the industry.

However, on the one hand, TPU film products exhibit highly unstable characteristics during production, requiring advanced technologies and equipment for development and testing. On the other hand, competition from alternative materials and economic considerations necessitate that TPU film manufacturing become more efficient—enabling the consistent production of high‑quality films to reduce costs. At the same time, there is a demand for a broader range of TPU film types, with thinner and thicker gauges, as well as the incorporation of cutting‑edge technologies to enhance material properties and thereby increase added value. These two factors have become bottlenecks constraining the development of domestic TPU manufacturers in China.

1.2 Current Status of TPU Film Applications

Due to TPU’s high strength, wear resistance, excellent elasticity, and weather resistance, TPU films are widely used in industries such as automotive, footwear, apparel lamination, ready-to-wear garments, chemicals, electronics, and medical applications. As many countries place increasing emphasis on environmental protection—particularly since the European Union banned PVC in materials like footwear—efforts have been made to identify suitable alternative materials.

Due to TPU’s environmental friendliness, non-toxicity, and ease of recycling and biodegradation, TPU film has become a superior alternative to PVC in footwear materials, and wherever PVC can be used, TPU can serve as a replacement. As a key credential for entering the European and American markets, test reports from internationally recognized testing organizations such as SGS, ASTM, JIS, and FDA are also highly important.

For example, the renowned film brand DingZing Film has long since obtained these certifications. Its films are of consistent quality, non-toxic, pollution-free, free from the eight major harmful heavy metals, and both incinerable and biodegradable—factors that have earned the brand widespread recognition worldwide.

TPU films are divided into two main categories: polyester and polyether. Polyester-based products offer superior heat resistance and chemical resistance, making them widely used as replacements for PVC products. Polyether-based films, on the other hand, exhibit excellent low-temperature resistance, hydrolysis resistance, and anti-mold and antibacterial properties, and are commonly employed in applications involving contact with water.

The application areas of TPU film can be broadly categorized as follows:

(1) Waterproof and breathable TPU films for textiles: The introduction of advanced hydrophilic groups gives TPU films not only high waterproofness but also excellent moisture permeability. This material breakthrough, combined with textile lamination technologies, significantly enhances the added value of textiles. Representative examples include DingZing’s Dintex brand and Germany’s Gore‑Tex brand. These innovative, practical fabrics are highly popular with consumers.

(2) A non-yellowing series of TPU films for UV protection.

(3) Hot-melt adhesive film TPU film used for bonding.

(4) TPU film for footwear applications: Its excellent printability and ease of processing make TPU an ideal film material for sports shoes, casual shoes, sandals, and other specialized footwear. Internationally renowned brands such as Nike, Reebok, Converse, and Adidas, as well as prominent domestic brands like Anta, Li-Ning, Xtep, and Hongxing Erke, are all heavy users of TPU film. Additionally, TPU film is the preferred choice for certain three-dimensional logos and trademarks.

(5) TPU Film for Blow-Molded Products It is worth noting that, due to the difficulty in precisely controlling the raw material ratios and reaction temperatures during synthetic TPU production, combined with TPU’s inherent instability, its thickness is hard to regulate. Consequently, manufacturers typically do not use film area as the basis for pricing. In practice, sales are usually measured in kilograms, as this approach more accurately reflects the material’s value. Meanwhile, companies that require the film generally focus only on the desired length and width. Therefore, the length (in yards) and weight (in kilograms) of TPU film often need to be converted. The market price of TPU film is approximately RMB 70 per kilogram, and it fluctuates in response to changes in petroleum prices and the costs of its synthesis precursors.

2 Research on TPU Films

2.1 Research on Raw Materials for TPU Film

Process: The three raw materials are heated separately in their respective storage tanks at temperatures of 90°C, 70°C, and 40°C. Metering pumps then deliver them individually to a mixing head, where a high-speed rotating rotor ensures thorough blending. The mixture is dispensed onto a conveyor belt; as it passes through a curing tunnel, the TPU liquid solidifies into sheets. These sheets are then crushed or pelletized and fed into an extruder, where they are extruded at 132°C for secondary pelletization.

2.2 Processability Study

The development of TPU films is closely linked to the processing methods for TPU materials and also imposes new requirements on the properties of the raw materials. Because domestically produced TPU pellets often fail to meet processing specifications, even when local manufacturers are capable of production, they typically import TPU pellets from overseas.

The main processing methods for TPU films include blow molding, cast extrusion, T-die extrusion, and calendering. The final product typically does not require vulcanization or crosslinking, which can shorten the production cycle, and waste material can be recycled and reused. TPU films can incorporate a wide range of additives and fillers to enhance certain physical properties, improve processability, or reduce costs.

Precautions for processing:

① Ensure that the material remains in the dryer for 4 hours, as TPU raw material is prone to moisture absorption.

② The viscosity of the material is highly sensitive to temperature and its fluctuations; therefore, it is important to carefully control both the reaction temperature and the localized temperature at the die.

③ In terms of thickness, mass-produced films exhibit a rather poor thickness distribution; therefore, the TPU film’s thickness should be accurately measured during production, tailored to the specific processing method employed, in order to achieve better control over film thickness.

④ The mold’s structural design must ensure smooth material flow and prevent any material buildup.

⑤ Due to the properties of TPU material, the drive power required by processing equipment is 1.5 to 2.0 times greater than that for processing certain general-purpose plastics.

Blown film is a relatively new process with low production volumes, and the material should be dried before processing. The drying temperature range for TPU is 82–121°C.

Strictly speaking, TPU film should not contain plasticizers, as they are inherently toxic chemicals. However, due to technological and equipment limitations, many companies resort to using them to reduce pellet viscosity, lower hardness, and decrease molecular weight for easier processing. The downside is that this leads to embrittlement, off‑odors, and oil blooming (migration) in the TPU film, severely compromising its physical properties and environmental compliance.

Currently, the thinnest TPU film available worldwide is 10 µm; Japan’s Mirac‑tran TPU can reach several tens of micrometers, while DingZing’s TPU film achieves 12 µm, outperforming TPU film manufacturers in South Korea, Japan, and the United States. TPU film products are highly suitable for bonding through heat pressing, high‑frequency processing, sewing, or adhesive application, and they also lend themselves to ink printing and vacuum or high‑frequency molding to create three‑dimensional effects.

2.3 Study on the Properties of TPU Films

The performance of TPU films has been studied primarily in terms of tear resistance, abrasion resistance, flexural durability, water resistance, yellowing resistance, low-temperature performance, heat and oxidation resistance, mold and antibacterial properties, oil resistance, gas permeability, and biomedical characteristics. Experimental results demonstrate that, compared with other conventional plastic films, TPU films exhibit superior performance across all these aspects.

2.4 Testing of TPU Film

Currently, TPU films produced on a large scale internationally still exhibit significant thickness variations. To capture a larger market share under these circumstances, state-of-the-art production lines equipped with advanced measurement and control technologies are essential. The inspection of TPU films serves two purposes: first, to detect pinholes and reject defective products; second, to monitor and control the film’s thickness. The thickness distribution is measured using a thickness gauge that moves vertically and horizontally around the bubble.

Some sensor elements and capacitive sensing components are also entering the thin-film measurement market. Currently, worldwide testing of TPU films reveals that most manufacturers produce rolls with 7 to 10 small pinholes per roll. Only a very small number of manufacturers can achieve just 1 or 2 pinholes per roll, and occasionally even zero.

Because the raw material ratios and reaction temperatures in TPU film production are difficult to control, many customers express dissatisfaction and complaints about product tolerances. Practical experience shows that even on the same day, using the same machine to produce parts of the same specification can sometimes result in significant variations. Therefore, for TPU manufacturers aiming to grow stronger and larger, increased investment in production technology and measurement equipment is essential. Only then can they deliver products that meet quality standards and satisfy customers. However, advanced TPU film testing equipment is often very expensive, making thickness control and defect rate management a major challenge for many small and medium-sized TPU film producers.

When inspecting TPU film during the purchasing process, it’s important not to cut off a small sample for evaluation. Instead, use an entire roll as the sample; this allows you to observe subtle details and differences. Currently, TPU films that are free of water ripples and surface imperfections, and remain perfectly flat, are best suited for logos on apparel and footwear. To protect the TPU film and maintain its smooth finish, PE, PET, or release paper is often used as a protective layer. As a result, the TPU film you see in practice typically consists of two layers; simply remove the protective layer before use.

4 Prospects for TPU Films

TPU film is an environmentally friendly material; thanks to its excellent properties and eco‑friendliness, it is seeing increasingly widespread use, giving it outstanding market prospects.

Printability ensures that TPU films will continue to experience rapid growth in footwear applications; the automotive sector also represents a significant market for both TPU films and broader TPU applications; inflatable products have likewise begun to see rapid growth in southern Chinese cities; waterproof–breathable membranes constitute a vast market, yet because they must be laminated to fabrics, substandard technology can damage the fabric itself, placing stringent demands on TPU film quality—demanding further advancement as technology progresses. In terms of biomedical performance, TPU films are non‑toxic, non‑allergenic, and non‑irritating, making them suitable for widespread use in medical and hygiene‑related products. In the construction industry, laminated membrane panels used as roof underlayment are projected to become a major market segment; moreover, their use in greenhouses as a replacement for short‑life polyethylene films holds considerable promise.

Additionally, according to Nike’s R&D team, screen printing on TPU film significantly increases labor time and processing steps. To save on manpower, financial resources, and materials, shoe manufacturers hope that TPU film producers can supply films in any color they require—this is an area where companies should focus their efforts.

In short, as market competition intensifies, only high-quality TPU films at reasonable prices will dominate the international TPU film market. Therefore, global TPU film manufacturers should invest heavily in technological innovation, develop new product varieties, and continuously improve their offerings to expand and enhance the market for this environmentally friendly material.