Difference Between TPU and Silicone

The key difference between TPU and silicone is that TPU material is better than silicone to be used in the production of mobile phone cases.

Both TPU and silicone are used in the manufacturing of mobile phone cases or covers. These two materials are commonly used for this application due to their ability to protect the mobile phone. For example, TPU material can protect the phone from collisions, without causing any damage to the phone. Moreover, TPU material is more transparent in colour and environmentally friendly.

CONTENTS

1. Overview and Key Difference
2. What is TPU 
3. What is Silicone
4. Side by Side Comparison – TPU vs Silicone in Tabular Form
5. Summary

What is TPU?

The term TPU stands for thermoplastic polyurethane. It is any class of polyurethane plastics having many properties such as elasticity, transparency, and resistance to oil, grease, and abrasion. We can classify them as thermoplastic elastomers. This material contains linear segmented block copolymers consisting of hard and soft segments.

Thermoplastic polyurethane is a block copolymer composed of an alternating sequence of hard and soft segments or fragments that are formed by the reaction between diisocyanate with short-chain diols and the reaction between diisocyanates with long chain diols. We can obtain a variety of TPU material by changing the ratio, structure or molecular weight of the reactants. E.g. if the ratio between hard and soft segments is great, then the resulting TPU is more rigid comparatively.

This block copolymer material contains low polarity segments. Both hard and soft segments in this polymer are linked to each other via covalent links, so they form block copolymer structure. The polarity of the hard segments creates a strong attraction between these segments. This leads to a high degree of aggregation and order, resulting in either in a crystalline or a pseudocrystalline material. These crystalline or pseudo crystalline areas in this material can act as physical cross-linking regions, which cause the high elasticity of TPU.

What is Silicone?

Silicone is an inorganic material we use as sealants, adhesives, lubricants, medicine, etc. We call it as polysiloxanes as well. It is the chemical name of this compound. These are polymer materials that consist of repeating units of siloxanes. Typically, silicone is heat resistant and is a rubbery material. However, sometimes, we can find it in its liquid form as well, depending on the intended application. It is a good thermal and electrical insulator. Common compounds that we use in day-to-day life include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

This compound can make watertight seals. However, it has a high gas permeability. That means, it is highly permeable to gases such as oxygen, which makes it useful in medical applications where we need more aeration. We can use silicone in the automotive field as silicone grease to act as a lubricant for brakes. It is also useful in coatings and provides surfaces with waterproofing ability. Since silicone is non-toxic and low-taint, we can use this compound when we need to make tools that come into contact with food. Liquid silicone is useful as a dry cleaning solvent. Moreover, it is resistant to microbial attacks, which provides this material with a long shelf life.

What is the Difference Between TPU and Silicone?

The key difference between TPU and silicone is that TPU material is better than silicone to be used in the production of mobile phone cases. This is because silicone material is a bad conductor of heat which can store heat in the mobile phone case that can cause heating the phone eventually. But TPU material can conduct heat out of the phone case and does not store heat as in silicone. Therefore, the phone is safe inside this cover. Moreover, TPU material is more transparent in colour, environmentally friendly, and more importantly, with TPU cases, the user will not lose grip of the phone easily.

Below infographic compares both materials and tabulates side by side the differences between TPU and silicone.

Summary – TPU vs Silicone

The key difference between TPU and silicone is that TPU material is better than silicone to be used in the production of mobile phone cases. Moreover, TPU material is more transparent in colour, environmentally friendly, and more importantly, TPU gives the user a good grip of the phone.

Reference:

1. “Thermoplastic Polyurethane.” Wikipedia, Wikimedia Foundation, 10 Dec. 2020, Available here.

Image Courtesy:

1. “Chips TPU” Par Luigi Chiesa — Travail personnel (CC BY-SA 3.0) via Commons Wikimedia
2. “Overview commonly used silicone systems” By Boltea – Own workselfmade with Power Point (CC0) via Commons Wikimedia