TPU material vs silicone cover image

TPU material vs silicone: Which One’s Better and Why?

We’re seeing a rise in the prices of smartphones. Remember when $1,000 was considered to be outrageous? Well, Samsung released the Note 20 with sub-par specs at a thousand bucks. With expensive phones come expensive risks of damaging them. And when it comes to protection, there are two options; extended warranty and phone cases, the most common being silicone and TPU. Let’s put these two sides by side in this TPU material vs Silicone battle and see what are these materials and which one is better.

Both TPU and silicone are polymer-based materials and used in multiple industries for their physical qualities. Both the materials are soft, mouldable, and easy to produce. This is why phone cases made from these two are cheap and easily available. Both the materials have some pros and cons and depending on the unique qualities they possess, phone cases are preferred.

What does TPU mean

TPU stands for Thermoplastic Polyurethane. We are not going to dive into the organic chemistry part of this material. It would be sufficient to say that TPU is made of repeating chains of the block copolymer. To understand it, imagine a mesh pattern with a dot at the intersection. The dots would be the block copolymer while the lines would be the connecting bridges.

TPU is not just used for making phone cases or such. Have you seen those dish-washing sponges? Those are made of polyurethane, a constituent part of TPU. TPU is very versatile, its uses ranging from dishwashing to medical appliances. But what makes this TPU material so apt for making phone cases? 

Since it is a polymer, there are some great qualities that TPU has which a case also needs. The most useful one is its high abrasion resistance. But before we get to know TPU better, let’s learn why it is such great material for phone cases and other appliances. Let’s look at the PC material.

PC – Polycarbonate material

Polycarbonate belongs to the same family of materials as TPU. In the case of PC, carbonate is the building block and is repeated (hence polymer). PC is highly resistant to shock. It is tough, durable, and very clear. You can imagine how tough it is since it’s used in F-22 Raptor’s cockpit covering. Polycarbonate is hard, tough plastic that feels very much like glass without the weight or fragility. Some lenses for spectacles are made of PC.

The problem with PC is that it is non-malleable and not very good at handling scratches. The hard material and difficulty turning it into different shapes made PC a problematic material for making phone cases. We need a material that is soft and malleable enough to act as a phone covering. This diverts us to another material with which cases can be made; Silicone. Let’s look at the pros and cons of silicone. 

structure of polymer material
How the structure of a polymer looks like. The green dots represent either carbon or silicon. This isn’t the actual representation.

Silicone material 

Silicone is a soft, rubbery material that is also very popular for making phone cases. The silicone material is thin, contours the phone body. Perhaps the biggest reason why people go for silicone cover is the soft material and great grip it provides. Silicone covers do not add to the bulk of the phone and they are very comfortable to hold. Silicone is also a polymer, the repeating element being silicon (different from silicone). The reason why silicon and carbon are used to make polymer is that they can form four strong covalent bonds.

The cons of silicone material 

When compared to TPU or even PC, there are many disadvantages of using silicone material for making mobile covers. The first and most crucial one is its inability to protect the device. Protection from shock (if the phone falls and hits a hard surface) is the primary reason why people get a phone cover. While silicone is good for protecting from abrasions and scratches, there is almost no fall protection. 

The other major issue is its durability. Silicone materials are poor lasting. While this material works well at lower temperatures, they are a poor performer at high temperatures. Continuous use (friction) wears them out and the silicone turns gooey and sticky. Not something you want to keep your hands on, especially when your phone also heats.

Another problem with the silicone cases is that they are dirt magnets. Silicone provides a great grip it sticks to the hands. And hands have a lot of grease and dirt which are swiftly transferred to the cover. Silicone is also prone to cuts and abrasions, further decreasing its longevity and reliability. 

Perhaps the only reason people use it is that it is cheap and does not add bulk to the phone. It acts like a soft cloth for the phone. So there are many problems with silicone material for phone covers (and not cases). This is where TPU or thermoplastic polyurethane comes in. It took the best things from both PC and silicone and combined them into one. 

TPU material to make the casing

TPU takes the best of both worlds. It is made of both hard parts and soft parts, giving it both qualities. Cases made of TPU are resistant to scratches, shock, and abrasion. They also don’t add to the bulk (not as light and thin as silicone but also not as bulky as plastic).

Most of the cases that come with the phones (like OnePlus, Samsung, Xiaomi, etc) are made of TPU. They are thick, transparent (and can be colored easily), and very flexible. 

TPU is also very long-lasting. Unlike silicone which turns gooey due to friction, the hardness of TPU makes it resistant to friction. So no matter how many times you pick up your phone, rub the case while putting it inside your pockets, TPU will last for years. But this does not mean that TPU is devoid of any flaws. 

phone with a TPU case on it
Phone with a TPU case on it

The cons of TPU as phone cases

Perhaps the biggest flaw in TPU cases is that clear TPU cases turn yellow after a year or so and this is, sadly, inevitable. And I have seen articles claiming soaps and bleach will help get rid of the yellow stains. That’s not gonna work. Here’s why. 

Why TPU cases become yellow? There are two reasons for it. First is the ultraviolet rays of the sun (or sunlight) and the second is the heat from it. These two reasons cause a chemical reaction in the chemical structure of TPU, changing the color. Since this is a chemical reaction, no bleach or soap can remove this yellow color. There are some cases with a composite material that do not turn yellow. But the cheap TPU cases will turn yellow. 

Summary 

Silicone material cases are soft to touch, very thin and flexible, contouring the body of the phone. This flexibility and softness add to the grip and feel of the phone while not adding to the bulk of the phone. There are some cons to this material as well. It is bad at protecting the devices from shock and is itself poor at scratch, cut, or friction resistance. 

Polycarbonate or PC is engineered plastic with great strength but it is brittle. This makes it a bad choice for mobile phone cases. Hence, TPU acts as a hybrid of silicone and polycarbonate. TPU stands for thermoplastic polyurethane. It is both hard and soft, transparent, and good at scratch, shock resistance. It is cheap to produce but turns yellow due to sunlight exposure. This was all about TPU material and silicone. We hope this article helped you understand the difference better.

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