Oerlikon Nonwoven: the master of TPU diversity
TPU nonwoven fabrics have many strengths, but they are not easy to develop. Now nonwoven fabric producers can get help when doing so, as Oerlikon Nonwoven has expanded its expertise and provides comprehensive support - from the choice of the right base material to its processing and setting the desired color.
Nowadays, thermoplastic polyurethane elastomers (TPU) are predominantly processed by injection molding. They are used in a wide variety of applications, such as timing belts or tool handles for industry, ear tags for cattle, football boot soles or clothing for outdoor enthusiasts and athletes, but it can also be processed very well into nonwovens using the meltblown spinning method.
The applications for meltblown nonwovens based on thermoplastic polyurethane elastomers are extremely diverse, as each of the numerous types of TPU elastomer has very specific properties in terms of elongation, tensile strength, wear and abrasion resistance, hardness and resistance to oils, fats, liquids, oxygen and UV radiation, which means that TPU meltblown nonwoven fabrics can be used to make products for a wide range of applications in the textile industry as well as in the medical sector.
TPU nonwoven fabrics can be used wherever their elastic properties are required. Because TPU nonwoven fabric is also breathable, it is ideal for sportswear, swimwear and seamless underwear, where another advantage also comes into play, as TPU nonwovens can be ultrasonically welded and the textile webs do not need to be sewn. Medical products such as wound dressings or diaper closures can also be made from TPU meltblown nonwovens.
But, as varied as the possible uses of TPU nonwoven fabrics are, so too are the requirements for the processing of thermoplastic polyurethane elastomers during the production of nonwovens. Producers of meltblown nonwovens therefore often specialize in the production of one or just a few types or grades of TPU.
Nonwovens producers need to invest a lot of time and effort in process optimization if they wish to expand their product portfolio and process another type of TPU. One of the challenges they face is the extreme temperature sensitivity of the TPU raw material, which means that the process parameters of the plant have to be set very precisely in the event of a production changeover from one type of TPU to another, a process which is often very time consuming.
Not only do the individual process parameters have to be exactly right, the plant technology as such also has to be designed for sensitive polymers.
Oerlikon Nonwoven’s meltblown technology is characterized by a constant melt pressure distribution as well as a constant polymer retention time over the entire width of the spinning beam, ensuring particularly homogeneous nonwoven properties and grammages, even when working with sensitive raw materials.
Through its extensive research work, Oerlikon Nonwoven has built up in-depth knowledge about the properties and processing of the various different types of TPU.
“If nonwoven producers want to switch to a different type of nonwoven or find a suitable type of TPU with specific properties, we can provide expert advice, help to adapt processes, or train employees,” says technology manager Michael Latinski. In addition, Oerlikon Nonwoven can undertake the complex development work for nonwoven producers on request.
There is another big advantage for manufacturers in the textile industry: not only does Oerlikon Nonwoven know which type of TPU is best suited to which application. Thanks to the cooperation with a masterbatch manufacturer, the nonwoven experts can also give recommendations on how to specifically dye TPU nonwovens according to the RAL color chart. For example, by adding the right amount of color granules, the nonwovens turn out deep black, instead of gray, or bright red rather than pink.