Polyurethane Fabric: What is PU and What is it Used For?

Polyurethane fabric, also known as PU-coated fabric, is incredibly popular across various industries because of its versatility and durability. We'll explore everything about these fabrics, from their advantages and disadvantages to their many uses, safety tips, and how best to take care of them.

Read more: What is Flame Retardant Fabric? How is it Different Than Flame Resistant Fabrics?

 

What is PU?

PU stands for polyurethane (PU). It's a type of polymer, which is a synthetic material made from petroleum byproducts.
 

What is polyurethane used for?

Polyurethane is used to strengthen fabrics, keeping them from getting damaged during sewing. You'll find polyurethane used in everything from clothing and footwear to furniture.

 

Why do we need to use polyurethane on fabric?

It's important to know that fabric isn't naturally fragile, but it can fray or unravel during sewing and cutting, which could ruin the product. PU treatment helps by binding the threads together to prevent fraying when the fabric is cut. Even strong materials like cotton, wool, or synthetic blends can break or tear over time, especially under heavy use. 
 

That's why fabrics or wool are often treated with a polyurethane coating before being shaped and turned into final products. This coating helps prevent the edges from fraying and extends the life of the fabric.

 

For instance, when making textiles for car interiors, sewing is a typical method used. To make sure the fabric remains durable and doesn't get damaged during sewing, it's often applied with a PU coating. 
 

What is polyurethane fabric?

Polyurethane fabric, also known as PU coating, is a layer of synthetic material made from petroleum and applied to fabrics like polyester, nylon, cotton, and leather to enhance their durability. This coating makes the fabric lighter, more water-resistant, and flexible. It can be applied to one side or both sides of the fabric, making it especially versatile.

 

This type of fabric is widely used across many industries because it provides extra protection. It's popular in making everything from medical equipment and diapers to activewear and pet products!
 

Polyurethane resin systems

All fabrics coated with polyurethane contain polymer resins. There are three different types of resins used in PU coatings, which can be used alone or mixed with other materials. The three types of resins include:
 

1. Polycarbonate (PC)

It is known for its excellent toughness and good heat resistance. This type of resin is often used in applications where durability and impact resistance are critical, such as in protective coatings, automotive parts, and electronic casings. 

 

2. Polyether (PET)

PET resins are great for their flexibility and ability to handle moisture well, making them perfect for wet environments. They're especially valued for staying strong and resisting germs, which is crucial for items used in damp places like boats, hydraulic seals, and certain medical devices.
 

3. Polyester (PES)

Polyester resins (PES) are ideal for less demanding commercial uses. For example, they work really well for products like headboards and pillows because they handle heat, light, and humidity well, despite not being highly resistant to these elements.

Wet and dry processes of polyurethane fabrics 

1. Wet polyurethane process

The wet polyurethane process begins by applying a special mixture known as a coagulated base to a material or substrate using various resin systems. Here's what happens: polyurethane, diluted with solvents or water, is applied on a roll similar to a glue stick. Once the fabric is loaded into the machine, it moves through and gets coated with PU. After coating, the fabric is then placed in an oven to dry.

As the fabric dries, the solvents evaporate, leaving behind a solid layer of polyurethane. This method produces a flexible and thin coating. However, it requires careful handling because the solvents can release VOCs—harmful vapors—while drying.
 

2. Dry polyurethane process

The dry process for applying polyurethane involves laying a solid layer of polyurethane directly onto a fabric or surface without using solvents or water. Typically, this is done using a hot melt or a thermoplastic urethane film that is laminated onto the fabric under heat and pressure. Unlike the wet process, which uses a coagulate base, the dry method adheres polyurethane directly to the backing, triggering a chemical reaction that significantly enhances the material's strength and performance. 

This method is termed "dry" because it doesn’t use liquid carriers, thus it’s more environmentally friendly; it emits no volatile organic compounds (VOCs). Additionally, it utilizes higher quality resin systems such as solid polycarbonate and polyether-polycarbonate. The process not only recaptures and recycles almost 100% of the solvents used, but it also consumes 25% less energy during the drying phase compared to the wet process.
 

The differences between PU and PUL fabric

Both PU (Polyurethane) fabric and PUL (Polyurethane Laminate) fabric come from polyurethane, but there's a key difference between them. PU fabric is a broad term for any fabric that has a polyurethane coating. On the other hand, PUL fabric specifically refers to fabrics that have been laminated with a polyurethane layer.

 

Feature	PU fabric	PUL fabric
Construction	Fabric coated with a layer of polyurethane.	Fabric bonded with a polyurethane film for lamination.
Water Resistance	Water-resistant, effectiveness varies by application.	Waterproof, offers complete barrier against water.
Breathability	Generally breathable, suitable for wearables.	Less breathable, though modern types can allow vapors.
Flexibility	More flexible, ideal for clothing and dynamic uses.	Less flexible, better for structured items.
Applications	Used in fashion items, raincoats, shoes, upholstery.	Used in baby bibs, mattress covers, medical garments.

 

Benefits of Polyurethane Fabric

Drawbacks of Polyurethane Fabric

Polyurethane fabric is inherently flammable. When exposed to fire, it can ignite and burn quickly, posing serious risks, especially in products that are frequently in close contact with children, such as baby strollers and toys.

To make polyurethane fabric safer, manufacturers often treat it with flame retardants, including phosphours-based chemicals. Flame retardants are chemicals added to materials such as tectile and plastic to prevent or slow the spread of fire. It makes PU-coated fabrics less likely to catch fire quickly and meet federal safety flammability standards. 

However, some types of flame retardants have been linked to health and environmental concerns, sparking demands for safer alternatives. Here are the issues with using flame retardants:
 

1. Health Concerns
Flame retardants can be toxic, especially to children. They may affect development and disrupt hormonal systems. This is particularly worrying for products like baby strollers and toys, which children use frequently and in close contact.
 

2. Environmental Impact
These chemicals don't just stay in the fabric; they can leach out and contaminate the environment. They're tough to break down, leading to long-lasting pollution that can harm wildlife and ecosystems.

Some companies or manufacturers would use materials that are naturally less flammable or develop new, chem-free fabrics. However, even naturally less flammable materials like wool still often require a PU (polyurethane) coating to prevent it from breaking under heavy use.

 

Any solution?

Like we mentioned earlier, even materials like wool, which are naturally less flammable, often need a PU (polyurethane) coating to make it more durable and flexible during the making process. There seems to be no way that fabrics can be inflammable yet chem-free. Fortunately, textile manufacturers have developed a new type of fabric with a PU coating that is tested to be chemical-free and meets federal safety flammability standards. That way, fabrics used in children's products, such as baby strollers and infant car seats, can be safe and free from harsh chemicals.

 

Common Uses of Polyurethane Fabric

• Fashion Industry: Used in making jackets, bags, and shoes.

• Upholstery: Popular in furniture coverings due to its durability and easy maintenance.

• Automotive: Used in car interiors for seats and trim.

• Children products: Baby strollers, toys, and infant car seats.

 

Final thoughts

Polyurethane’s widespread use is due to its durability, flexibility, and resistance to water and chemicals. Even strong materials like wool still often require a PU (polyurethane) coating to prevent it from breaking under heavy use. However, PU itself can be flammable, creating a bit of a dilemma. And we are here to help. Yu-City provides PU fabrics that meet fire safety standards and are tested chemical free. You’d get the highest quality materials without compromising on safety. Let us help you find the perfect PU fabric for your needs!

 

FAQs

1. What is polyurethane in a fabric?

Polyurethane in fabric refers to a polymer that is applied as a coating to enhance the material's durability, flexibility, and resistance to elements like water and stains.

 

2. What does polyurethane fabric feel like?

Polyurethane fabric typically has a smooth, sometimes rubbery texture. It can also mimic the feel of leather, depending on the finish and application.

 

3. Is polyurethane fabric safe to wear?

Yes, polyurethane fabric is generally safe to wear. It is commonly used in many types of clothing, including outerwear and fashion accessories.

 

4. Is polyurethane fabric waterproof?

Polyurethane fabric is water-resistant and can be made waterproof depending on the thickness and method of application of the polyurethane coating.

 

5. What is 100% polyurethane fabric?

100% polyurethane fabric means that the material is entirely made of polyurethane without any other underlying fabric layers.

 

6. What is the difference between polyester and polyurethane fabric?

Polyester is a synthetic fiber used primarily for fabric manufacturing, known for its durability and resistance to shrinking and stretching. Polyurethane is a type of plastic used as a coating on fabric or as a solid material for waterproof and flexible properties.

 

7. What are the disadvantages of polyurethane?

It's quite flammable, so manufacturers often add flame retardants to make products with PU coating less likely to catch fire. However, since flame retardants can be harmful to children, more and more brands are searching for fabrics that can meet fire safety standards without using these chemicals.

 

8. Will polyurethane fabric peel?

Over time and with extensive use, polyurethane fabric may start to peel, especially if it is of lower quality or not properly maintained.

 

9. Does polyurethane fabric melt?

Polyurethane can melt or deform when exposed to high temperatures, so it should be kept away from direct heat sources.

 

10. Is polyurethane fabric stretchy?

Polyurethane adds a degree of stretchiness to fabrics, making them more flexible, which is why it's often used in active wear.

 

11. Can you machine wash polyurethane fabric?

It's generally recommended to hand wash or use gentle cycles for polyurethane-coated fabrics to prevent peeling and maintain the integrity of the coating.

 

12. How do you take care of polyurethane fabric?

Care for polyurethane fabric by cleaning it with a damp cloth, using mild soap for stains, and avoiding high heat and harsh chemicals. Always check the care label for specific instructions.

 

13. Does polyurethane fabric breathe?

Polyurethane fabric is not as breathable as natural fabrics like cotton, which can make it less comfortable in warm conditions unless specifically designed for breathability.

 

14. What material is PU?

PU, or polyurethane, is a synthetic polymer that can be used as a substitute for leather. It mimics the look and feel of genuine leather very well. PU leather is completely artificial, which is a great vegan option.