Is Polyester Waterproof?

No natural or synthetic fabric exists in its purest form that is completely waterproof; all such fabrics have been altered or blended to acquire this property.

Polyester fabric may not be completely waterproof, but it is water-resistant and still useful, especially during harsh weather like the wet season.

Does Polyester Absorb Water?

Polyester fabrics are resistant to moisture. And together with nylon, it is one of the two most popular types of water-resistant fabric.

Many people often think that waterproof means the same thing as water-resistant.” However, one cannot be used interchangeably with the other. Waterproof materials have no gaps through which water or air can seep. Typically, you’ll rarely see that in textiles. However, the fabric weave of water-resistant fabrics leaves very few pores.

Polyester’s water resistance comes from its thick construction, which prevents water from penetrating. The fewer holes any material has, no matter how big or small, the more water resistant the material is because it’ll take longer for water to seep in when the fabric and construction are dense. It’s all about how closely the fabric yarn is woven. 

To prevent moisture from leaking through the fabric’s holes, it should have a high Denier count weave or be treated on the outside or inside.

For instance, a 300 or 400D polyester would be woven with about 300 to 400 crossing threads and the same weft threads, whereas a 1000D fabric would be woven even more tightly to accommodate 600 crossing threads and 600 weft threads more. It essentially means that the smaller the hole through which water may slowly seep, the higher the denier.

Although individual polyester threads have a reputation for water resistance, woven polyester fabrics do not. Because ultrasonic welding is required to seal a fabric’s seams thoroughly to make it waterproof, just regular stitching won’t do the trick. 

Types of Waterproof Polyester Fabrics

Being waterproof means that there is an addition of coatings to the outer layer of fabric. Polyester fabrics in the same light include; 

  • Thermoplastic polyurethane

Thermoplastic polyurethane fabric is constructed by sewing a polyurethane membrane onto a polyester backing. And this makes it watertight and windproof. TPU, however is softer than PUL, although it may not be as long-lasting.

This material is stretchy, waterproof, and resistant to the sun’s rays. That’s why it’s used in waterproof cloth diapers, survival jackets, and other outdoor gear. 

  • PUL” 

PUL, which is Polyurethane laminate in full, is a synthetic fabric constructed from a layer of laminated material over a layer of very thin knit polyester with the fabric either bonded or fused to the lamination.

PUL is often machine-washable, allowing for air circulation and a modest degree of stretch.

It is a popular material for various home decor and practical applications, including shower curtains and upholstery. 

  • 100% Polyester Fleece

Polyester is a water-resistant fabric, and blending with fleece supports its increased resistance. However, the quality and fiber content of the fleece in the blend determines whether or not it will repel water. The greater the density of the fleece, the greater its water resistance. 

That’s why it is widely used as the outer layer of cloth diapers and other wet environments. 

  • PVC Polyester

PVC polyester is completely impervious to water and is constructed by applying a polyvinyl chloride coating to the reverse side of the polyester fabric. 

Because of this backing, PVC-coated polyester is relatively rigid, incredibly sturdy, and long-lasting due to its high denier. 

This polyester type serves great use in the production of umbrellas, suitcases, and banners.

Polyester vs. Nylon

Nylon is another synthetic fabric that shares properties with polyester. In comparison to polyester’s 0.4%, nylon’s recovery is a much higher 4%. This means that polyester is more water resistant than nylon since it absorbs less moisture. In comparison, nylon is substantially more absorbent. 

Nylon and polyester are permeable to water because of the tiny spaces between their fibers. However, they can be protected against moisture by a coating because the coating or finish added to a textile fabric is what actually determines whether or not it is waterproof.

Nylon and polyester are both widely used for waterproofing items, including raincoats, tents, and bathing suits. Water-repellent characteristics beyond those inherent to polyester are often achieved through blending with another fabric or special treatment.

Is Recycled Polyester Waterproof?

Recycled polyester fabric is equally tough, long-lasting, and water-resistant as regular polyester. The fabric somewhat possesses thermal comfort and moisture-wicking features and is much the same as the standard waterproof material.

Recycled polyester is produced using eco-friendly methods, such as recycling PET bottles, post-industrial polyester waste, or even old polyester clothing. And is an excellent option or alternative to regular polyester. 

Some Water-resistant Polyester Blends

Water resistance can only be achieved through finishes and chemical treatments, but this does not make the item waterproof. A polyester fabric blend must be coated with a waterproofing agent to be considered waterproof.

The following are some water-resistant polyester fabric blends. 

  • Polyester-Spandex blend

This fabric blend is probably the commonest you’ll see. It is very popular and is used in activewear, swimwear, and other clothing types like yoga pants. 

  • Polyester-Cotton blend

As the name implies, it is a fabric blend of polyester and cotton. And each fabric has its unique features.

Cotton is soft and breathable, but when blended with polyester, they become more sturdy and resistant to tear. 

This fabric blend is also popular due to its lower price than 100% cotton. Although the polyester-cotton blend is comfortable, it is not very water resistant because of the cotton content.

  • Polyester-Wool Blend

The Polyester-wool blend can withstand some moisture because both polyester and wool fibers are water-repelling. This cozy fabric blend is commonly used for winter coats, although it is not 100% watertight though.

Is Spun Polyester Waterproof?

Spun polyester is rather water-resistant than waterproof. Even though the fabric’s natural pores are smaller than those of conventionally manufactured polyester, it is still not completely waterproof unless treated with a coating, a membrane, or some other technical finishing.

First, the primary components of spun polyester are identical to those used in producing standard polyester fabric.

Polyester fibers can be spun into a soft and smooth material by first cutting them into short fibers and then merging all the short pieces.

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