Is Polyester Waterproof?

Polyester is commonly used in clothing, including outdoor gear, due to its water resistant features. Polyester can be made waterproof through several different ways including combining it with another material or using a spray coating.

In this article, we’ll explain what polyester is, how water resistant it is, and its suitability for use in outdoor clothing.

What is polyester?

Polyester is a kind of synthetic material that is most commonly made from petroleum. Though it can also be made from recycled plastic, this doesn’t occur as frequently. 

The word polyester comes from two words: polymer, which means to have many parts, and ester, meaning a chemical compound.

Durable, versatile, and lightweight, polyester is an ideal fabric that has many uses. It is relatively inexpensive when compared with other materials. 

Polyester has been used in the United States since the 1950s. Even though it is a fairly new product, it is the most commonly used fiber in the world.

How is polyester made?

After being extracted from the earth, petroleum is sent to a refinery where ethylene and p-xylene are derived from it. Heat, pressure, and other methods are used to break down the petroleum into different byproducts.

P-xylene produces two compounds called dimethyl terephthalate (DMT) and terephthalic acid (TPA). Ethylene produces ethylene glycol. These three components are heated and put under high pressure to produce something called polyethylene terephthalate (PET).

The PET is dried and made into plastic pellets. These are then melted and formed into long threads. When the threads are cooled, they harden into a polyester fiber.

What is polyester used for?

Since polyester is such an inexpensive and durable material, it is used in several different industries to make many products.

Various types of clothing are made from polyester including jackets, hats, pants, and shirts. Polyester is ideal for clothes since it dries quickly, doesn’t wrinkle, and doesn’t tear easily.

This material is also used to make bedding including sheets and blankets. Cushions, comforters, and pillows can also be filled with polyester fiber. Furniture upholstery can be made with polyester as well.

Other uses for polyester include seat belts, bottles, ropes, and conveyor belts.

What is the difference between waterproof and water resistant?

When it comes to a fabric’s ability to stay dry, there are two ways that it may be characterized: waterproof or water resistant. Waterproof materials are the most protection you can get from moisture, while water resistant materials are a bit less protective.

Waterproof materials do not let any moisture through. They are a complete physical barrier to water. Since they do not let moisture through, they are considered to be non-breathable fabrics.

The majority of fabrics are not waterproof on their own, but need to be coated with a special sealant or combined with another fabric to make them waterproof.

Water resistant materials repel water from the surface of the fabric. If they get wet enough the weight of the water can cause it to seep through eventually. 

Fabrics that are water resistant are sometimes called “everyday waterproof” because they do a good enough job at repelling water for most purposes.

Is polyester waterproof or water resistant?

Polyester is not 100 percent waterproof in its original state. Threads of polyester are basically waterproof, but when they are woven together to make a fabric, this creates small areas in between the threads. Since water can get through these holes, the material is not considered waterproof.

Polyester is water resistant enough that it is commonly used for rain gear, backpacks, even shower curtains. 

When choosing an item made from polyester, look at the denier rating. Denier refers to how closely woven the threads of polyester are. The higher this number, the more resistant the polyester will be to water since the spaces between the threads are smaller. 

Denier is shown as a “D” number, for example, 40D. A rating of 40D is adequate for rain gear, though if you spend every day outside in heavy rains you may want to look for gear that is 80D.  

Can I make polyester waterproof?

There are a few options when it comes to making polyester waterproof. The first option is to use a spray coating. These are usually made from silicone or water repellant elastic polymers. Spray coating can be used on clothing as well as furniture like couches and chairs.

Another option is to purchase items that are already combined with a waterproof fabric or coating. Poly-vinyl chloride (PVC)-coated polyester is simply polyester that has been coated with PVC.

Polyurethane laminate (PUL) is a type of compound fabric that is made by laminating polyurethane to polyester. Similarly, thermoplastic polyurethane (TPU) combines polyester with a polyurethane membrane. 

Is polyester good for rain?

Polyester is a great choice for rain jackets and other rain gear. For everyday use, a regular polyester material is water resistant enough to keep you dry.

If you will be spending a lot of time in heavy rains, choose either PVC-coated polyester, PUL, or TPU. Alternatively, use a waterproof spray on a polyester rain jacket.

In addition to being great for wearing in the rain, polyester also provides protection against the wind. It is also easy to clean and relatively inexpensive.

Can polyester absorb water?

The polyester fabric itself does not absorb any water. The reason you may get wet when wearing polyester is that the water seeps through the tiny holes between the threads of polyester woven together.

What happens when polyester gets wet?

Polyester is a fairly quick-drying material. When this fabric gets wet, it does not get damaged. Since it is able to repel water fairly well, polyester will dry quickly once out of the rain.

What material is most waterproof?

Vinyl is considered to be one of the most waterproof fabrics. It is not commonly used in rain gear since it is not a breathable material and is uncomfortable to wear. It can be a good choice for other products like outdoor awnings or for flooring in kitchens and bathrooms.

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