Can you soften a thermoplastic polyurethane without plasticizer? YES!

P-XX50 series, Kuraray’s new bio-based, polyester polyols, offers customers?powerful properties and a sustainable solution.

Thermoplastic polyurethane (TPU) is multiblock copolymer used as a key building block in numerous products because of its strength, durability, flexibility, and resistance to abrasion and wear and tear. You can find TPU in industrial and medical tubes, smartphone cases, shoe soles and paint protection films, to name a few products.?

But, if you need to make a softer TPU, manufacturers often rely on a plasticizer – a synthetic resin that promotes flexibility and reduces brittleness. There are mixed reviews on the use of plasticizers, plus there is a huge push for more sustainable products. Kuraray recently unveiled new bio-based, polyester polyols based on their unique diol, MPD, called P-XX50 series. By properly integrating P-XX50 series into a formulation, designers can achieve the level of desired softness in a TPU without the need for plasticizer. Here are some FAQs I’m often asked about this innovative product solution.?

Q: What is the concern around using plasticizers in TPU to achieve softness? ???

A: Phthlates are chemicals used to make plastics soft and flexible, and as a result, they are commonly used as plasticizers. However, plasticizers are known to “bleed out,” meaning the liquid migrates to the surface of the end product. If you’re manufacturing a medical product, for example, there may be concern that a harmful plasticizer could bleed out, leach into the blood stream and cause potential health issues.??

Q: What are the key ingredients of P-XX50 series? ???

A: P-XX50 series has two main ingredients: an aliphatic diol known as MPD (3 - methyl - 1,5 - pentanediol) and sebacic acid derived from castor oil. MPD has many distinctive properties, such as remaining a liquid even at low temperatures, low viscosity and good transparency. The sebacic acid from the castor oil helps us achieve the bio-based, sustainability portion of the product.?

Q: So describe Kuraray’s process for creating a soft TPU using P-XX50 series?????

A:?P-XX50 series is liquid at room temperature. This feature allows for easy handling and potential energy reduction when producing TPU. When you convert MPD bio-based polyol into polyurethane, the flexible nature of MPD combined with durability of sebacic acid allows the manufacturer to create soft TPU without a plasticizer having high heat resistance and low water absorption.?

Q: What are some of the other features of this new MPD bio-based polyol?????

A: They are available in molecular weights from 500 to 6000. This allows for a wide range of TPU designs with an excellent balance of softness, good heat resistance and low water absorption. Plus, there is the added benefit of potentially lower energy consumption with the?low viscosity and ease of handling.?

Q: When did Kuraray first unveil P-XX50 series and what has been customer reaction???

A:??Kuraray has produced MPD bio-based polyols for several years. But, the P-XX50 series with the expanded molecular range was just recently unveiled. Some customers have already begun using P-XX50 series in products such as artificial leather. Reviews have been positive, especially regarding sustainability and performance.??

Q: Do you have more technical information and research to back up your claims about the P-XX50 series????

A:?Yes. Two of my colleagues and I jointly wrote a technical paper that was recently published in the September 2024 issue of Rubber World. The paper chronicles our research in testing the P-XX50 series for its tensile property, heat resistance, moisture absorption and more. You can read that white paper here.

To learn more about Kuraray’s P-XX50 series, click here.??