Does Polyester Shrink? How About Viscose (Rayon)?

No, polyester will not shrink if put in the dryer and exposed to high heat since it is a resilient synthetic fiber as compared to organic fibers like cotton or wool. While polyester does not shrink, it is possible to melt the synthetic fibers under very high heat.

You will likely find viscose, also known as Rayon, will shrink in the dryer. This is because while viscose is a synthetic material created from cellulose it is often mixed with organic fibers such as cotton and silk which very much do shrink.

Remember that time you bought an expensive sweater and it shrunk after you washed it? Most of us have had a similar experience at some point in our lives. Sometimes clothes shrink quite noticeable often rendering unbearable. But other times they shrink just about enough to fit more tightly.

When that happens you might be inclined to think that you need to lose some weight. But the first thing to do is to check whether your clothes have been shrinking.

To some extent, you can reduce shrinkage of clothes by following the cleaning instructions on their label closely. But there is only so much you can do about it.

Why Do Clothes Shrink? 

The reason why some items of clothing shrink over time relates to the fibers they are made out of. There are two main groups of fibers that are used for clothes production:

  • Synthetic fibers.
  • Organic fibers.

What are synthetic fibers made out of? The characteristic that distinguishes synthetic fibers from organic fibers is that synthetic fibers are man-made from chemical chains that are based on petrochemicals. When we talk about synthetic fibers, we are talking about polyester, spandex, nylon, olefin, acrylic, rayon, etc. Collectively, they are known as polymers.

Now, polymers never shrink. So, if you want clothes that will stay the same size then you should buy clothes made out of synthetic fibers only. But why do these fibers not shrink? The reason why nylon, polyester, etcetera do not shrink is that the temperatures that washing machines wash at (even at their maximum temperature) are never hot enough to make these fibers shrink. Nothing happens to their molecular structure unless exposed to the kind of high temperatures that no washing machine would reach.

What are organic fibers? Unlike, synthetic fibers, organic fibers are found in nature. Cotton, silk, and other organic fibers are not man-made. So, while polymers are made in such as way that they are ready to be woven, organic fibers because they are not manufactured they are not straight but tangled. What this effectively means is that these organic fibers need to be stretched even before the can be used to make clothes. And it is precisely this stretching that causes molecular tension. So, even before the piece of clothing is manufactures, the molecular structure has been “messed with”.

Does Polyester Shrink?

I always wanted to create clothing that was universal – easy to wear, to care for, and that was also beautiful. As such, I became interested in polyester, and its potential, from the beginning of my career. – Issey Miyake

Although there is very little chance that polyester clothes will shrink accidentally, there are ways to make it shrink.

The good news is that it is virtually impossible for clothes to shrink accidentally. The bad news is that if you want to shrink polyester this will take some time and effort. It can be done but you will need to make a concerted effort. The first thing that you will need to do is to turn the item of clothing in question inside out. Then, you would need to wash it at the highest possible temperature, preferably by itself. Once the garment has been through the cycle, put it in the dryer without wasting any time. And choose the highest possible temperature for the drying out process.

Because polyester resists shrinkage so much, you might need to put the garment through this washing and drying cycle a few times over. Just make sure that you check it for shrinkage every time.

Why Does Viscose Shrink? Is There A Way To Avoid This?

As we have seen, rayon is one of the synthetic fibers. And viscose is simply a kind of rayon. Therefore, you might expect it to be quite resistant to shrink. But viscose is not purely synthetic. At least, not always.

More likely than not, viscose is also mixed with organic fibers such as cotton and silk. And this means that, unfortunately, viscose clothes are susceptible to shrink. But not only that, because its delicate molecular structure it is quite common of viscose clothing to become damaged if washed using a washing machine. That it is why hand washing is recommended.

Oftentimes washing it by hand is not really enough. You would have to make sure that you wash these garments with cool water and using a detergent that would be gentle enough to deal with viscose fibers without damaging the item of clothing.

It is also important to avoid twisting or wringing the garment as you wash it. Once you are done washing it, it is better to avoid hanging it to dry it out straight away. Also, you should avoid using a dryer. Instead, you should put the viscose piece of clothing on a cotton towel think enough to absorb the humidity. Once the water has been absorbed by the think towel and the garment in question has become noticeably lighter, you can hang it. Make sure that there are no creases and that the piece of clothing retains its original size and shape as you drive it. Any creases that are left once the item is fully dried would be near impossible to eliminate.

Why Does Cotton Shrink?

One of the most notorious fabrics when it comes to shrinkage is cotton.

Cotton fibers are made up of long molecular chains, linked by carbon and oxygen bonds. These long molecular chains are so much twisted and stretched so much that they become stressed even before the fabric is made. But it is this stress that keeps the fabric in shape and size. The problem is that one a piece of clothing made of cotton is washed, some of the stress is released.

So, with cotton more than shrinkage, there is a risk that the garment could lose its original shape after it has been washed several times. This could be avoided to some extent (or, at least, delayed as much as possible) by using the cotton option on your washing machine.

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  • Juan Ramos has many ‘facts’ incorrect in his article. He is not knowledgeable about textiles, fibers, yarns nor how they are made. He should educate himself on the definition of ‘petrochemical.’ There are so many incorrect statements in his article they would take up more space than the article. As a scientist, I appreciate and respect those who get their facts correct before publishing them. It seems that this is more of an ‘opinion’ article that fact. This article should have been proof read before appearing on the website.

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