Research on Rayon: Pulp, Hemp, and Bamboo

I thought I’d bring together a few scattered thoughts and links on rayon production and processes in one post, but beware, this is an overview and not an in-depth study of rayon production.  When I mentioned working with rayon-made-from-hemp the other day, I started digging around for information on rayon production.  Whew- what a lot of information to wade through!   I don’t want to embarrass myself by trying to talk about physics or chemistry.  If you’re interested in those aspects of rayon production, then please do follow the links.

I’ll break Rayon into three parts: Definition, Manufacturing/Sustainability, and Practical Use.

Definition: A Man-Made Natural Fiber

Rayon was discovered by Count Hilarie de Chardonnet in the 1884. (Some sources claim it’s much earlier.)   He and Louie Pasteur (yes, that Pastuer) were looking for a cheap alternative to silk when France’s silk moths were under threat from disease.

Rayon derives from natural fibers, usually wood pulp or cotton, and is processed and chemically re-arranged to form strands of fiber which produce a soft, absorbent, drapey fabric.

Click for source, and for a detailed description of the chemical process

The process varies, and has changed over the decades but most of my sources agree it goes like this:

To make rayon, sheets of purified cellulose are steeped in caustic soda, dried, shredded into crumbs, and then aged in metal containers for 2 to 3 days. The temperature and humidity in the metal containers are carefully controlled.
After ageing, the crumbs are combined and churned with liquid carbon disulfide, which turns the mix into orange-colored crumbs known as sodium cellulose xanthate. The cellulose xanthate is bathed in caustic soda, resulting in a viscose solution that looks and feels much like honey.

Caustic soda is the same thing as lye used in soap making, and is also found in Drano.

Click for short article on industrial synthetic fiber creation…

Once the honey colored viscose solution has aged a few days (it varies), the solution is forced through “spinnerets” which look like shower heads.  Rayon is “wet processed” which means the viscose is exposed to sulfuric acid, sodium sulfate, and zinc sulfate to turn the liquid viscose into useable fiber.  The gases (CS2 and H2S) released during this process also find their way into the environment.

Manufacturing and Sustainability:

Since the roughly the mid-90’s, (judging by the literature I found) manufacturers searched for a cheaper way to produce rayon with fewer toxic by-products.  One way way is electronic beam processing:

Electron processing renders the cellulose more
accessible to chemicals and reduces the amount of alkali,
carbon disulfide, and acid used in the process. In addition
to potential savings of about US $3 million per annum
for a typical plant, the lower chemical demand translates
into reduced emissions of polluting chemicals. Electron
processing may allow a plant to stay in operation under
current emission standards, or expand its operation
without the need for further pollution control.

–“Electronic Beam Processing: A New Business and a New Industry

Tencel is another type of rayon, made from Euclyptus pulp.  The process sets Tencel/Lyocell apart from other rayons because it is a closed-loop system.  That means that it reuses the waste created in the process.  That’s nifty.

Another aspect of rayon and textile sustainability involves the fibers used to make the rayon in the first place.  Most of the time, bamboo sold for clothing is actually rayon.  The material began life as a bamboo shoot, but went through one of the processes outlined above to become a fabric.

Hemp, too.  Hemp is my favorite fiber because of its sustainability cred, but I admit I’m a little conflicted about wearing hemp rayon jersey.  Is hemp or bamboo jersey more or less sustainable than cotton or other rayon?  Probably.  Both hemp and bamboo grow much more quickly with fewer chemicals and less water usage than cotton.  Both bamboo and hemp grow exponentially quicker than wood.

Practical Use (subjective opinion!):

Click to view the Sailor Sweetheart Top, made of rayon and already a victim of pilling and stinkage.

I don’t like sewing with rayon jersey.  There, I said it.  In my experience, rayon jersey pills if I look at it sideways and begins to stink after the first sweat.  It’s maddening to sew- much more wiggly than regular t-shirting fabrics.  The bindings and design details tend to crumple in the wash, even when I’m careful to take everything out and dry it immediately.

Made of bamboo- not quite dead, but longer than it was at the beginning of its life and not the greatest t-shirt ever.

Plus- I noticed that bamboo jerseys tend to “grow” just like knitted garments made with bamboo yarn.  Any knitters out there notice that?  It’s the same, the hem creeps slowly downwards.  I have yet to find any bamboo fabric that doesn’t pill (some are better than others), it grows, and it is extra wiggly compared to regular rayon.

The hemp-rayon jersey may be different.  I have a swatch that has gone through six loads of washing thus far without pilling.  I’m impressed.  It’s not as “wiggly” either, and has a nice lightweight but firm hand.  The hemp rayon differs from hemp jersey- I used some of that last year for a dress and two shirts- plain hemp jersey(mixed with organic cotton and a whiff of lycra) is somewhat heavy and curiously “nubbly.”  This hemp rayon is smooth and extremely lightweight.  I have some purple I’ll use later this month for June’s hack…

I found this delightful old video on rayon production while researching the topic- check it out for some lovely mid-century optimism and a look at the process of making rayon.
Do you sew with rayon?  How do you like it?  (You don’t have to agree with me!)

29 comments

  1. Fascinating. A while back ago I ordered about 15 swatches of rayon (the bamboo and synthetic kinds) and the excitement I felt opening the packaged went up in a poof of smoke the moment I handled (fondled?) them. You can tell just from feeling them that they’d distort out of shape the second you was them, not to mention the difficultly you’d have in sewing them. I wasn’t aware of their incompatibility with sweat though! They just don’t bounce back like other fibres with stretch. Shame, really.

    • I think most rayons have at least a little lycra in them to help them bounce back, but no, on the whole I’m not terribly impressed with them. I tried.

  2. Y’know, the first time I ever sewed with rayon it was a woven, and I really loathed the way it wrinkled in a way made linen look like a high-twist wool crepe by comparison. That was years ago – like 25 years ago. Then the sewing world got all crazy about knits, but I HATE polyester with a profound loathing, and refused point blank to sew any of the knits that I found. Then I stumbled upon some lovely rayon-lycra knits online and have never looked back. I haven’t found that they stretch out of shape – maybe that’s the lycra? – or pill horribly. I did try some bamboo – purchased from ebay to try – and was really disappointed in the flimsiness of the fabric and the pilling. I’m really disappointed in all things bamboo these days, including the “linen” that was given to me. But I’m liking the rayon-lycra combination.

    • I like and don’t like woven rayon… I think it’s on a “piece by piece” basis… Where did you find your non-pilly rayon?

      What did you not like about the “linen”? Curious. The linen is usually the non-chemically-treated stuff, or less so. Interesting…

      • Yes, Like and Not Like is my reaction to woven rayon. There is no way to predict ahead of time which piece will behave itself nicely and which piece will lead you to say unkind words out loud in front of toddlers! All are relatively cool to wear in a hot climate. Most have a decent drape and hand. Some pill excessively, and sag and droop worse than my 95-year-old grandaunt. Rayon is like the Christmas toys you yearned for as a child. Some of them delight beyond all expectation, and some disappoint you.

      • I must confess to being an Irish linen snob. It was the only linen that I sewed with for a very long time, and the first time I worked with the bamboo it just felt funny somehow. Can’t explain it, but maybe I’m being unreasonable! As for the non-pilly rayon knit, I’m going to have to confess to eating humble pie. Y’know – post a comment and investigate later. I did go upstairs and compare all the knits I own, including some high end RTW cotton tees. And they ALL pill. The rayon/lycra I was thinking of has been washed a few times, but never in the dryer, and after thoroughly inspecting it I was a surprised to see it had pilled on the inside of the dress, though the right side was pill-less. ?! It was purchased online. The one rayon/lycra me-made casual tee that I’ve worn and washed a lot has pilled, but I just chalked that up to cheap material, since it came from my local Fabricland, and they generally never stock anything high end. Working with knits is new to me, so I have no idea how a really excellent ITY or silk would stand up to wear. :)

  3. I haven’t noticed any distortion of my knitted garments (bamboo & cotton mix) I machine wash them and dry them flat though. I never hang my handknits out on the line! X

  4. Oh boy. The “designer off-cut” bamboo jersey I got has been HORRIBLE. I feel sorry for the people who bought designer duds made out of this fabric, because after the second wash, it was already toast. I think I wore my tee 5 or 6 times, and then I threw it out. It wasn’t even good enough for a rag.

    I haven’t found hemp locally, but the organic cotton French terry is a dream.

    • I have had very very bad pilling with bamboo. To be fair, not with every piece of bamboo I’ve ever worked with, but consistently enough that I decided to just not work with it anymore. What’s the point of making something I can only wear a handful of times?

      What do you mean by local hemp? There’s heaps of hemp merchants in the US… Hemp Traders is one, Near Sea Naturals (though they’re kind of pricey), Fabric.com actually has a decent array of hemp and organic cotton/ hemp..

      • Shipping to Canada is usually prohibitively expensive, especially on a student’s budget. I’m looking for a source that sells hemp fabric locally, where even though it may cost a little more, at least I’m not getting walloped by shipping costs.

        I’ve had shipping costs end up being more than the fabric a few times now, so my policy has changed from ‘maybe’ to ‘no way’.

  5. I find it so interesting that people have had problems with the rayon knits. I have a few dresses and tops that I’ve made out of rayon knits (some standard rayon and one bamboo) and even the ones that I wear at least a couple of times a week are not stretched out of shape, no pilling, and as far as I can tell doesn’t smell particularly bad. I think most if not all of them include lycra though so maybe that’s helping with the ability to keep the garment shape.

    • It may be the lycra, it may be whatever kind of rayon… From what I found in reading about production, the manufacturing process varies wildly. Which is quite interesting, really. I wonder if I can go pester some rayon manufacturers to find out what exactly they do with their fabrics??

  6. Wow, what an interesting post. I have only sewed bamboo jersey once and that top grew during the sewing process. The fabric felt divine on my skin, but a nice little long sleeve t-shirt ended up like a dress for an elephant. I am actually in the process of knitting a cardigan from a bamboo yarn, so I’ll let you know if it does the same thing! I haven’t used any hemp jersey, but as I love woven hemps I am sure I would love it, too. I remember having a rayon tie-dyed bikini when I was a teenager. It had little ties at the side that held it together. One day when I was walking up the beach out of the surf one side had come a little loose, so I re-tightened the ties and they snapped, leaving me … exposed …so my conclusion is that rayon and sea water don’t mix but then that’s gone right off topic!

    • Oh! That’s not funny but it is kind of hilarious… ;) I think the bamboo without lycra grows quite badly, with isn’t so bad. It still stinks, though.

      Too bad, too! It feels so good on the skin, like you said.

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  8. I do sew with rayon jersey blends, and I’ve also found them extremely wiggly, pill prone and hard to handle at times. I thought that rayon challis would be as fiddly, but I found it much easier to work with than I expected.

    I also agree that all rayon and rayon blends are not created equal. I have two challis prints that seem very delicate next to the sort of hardy red dotted one I made a skirt with recently. And some of my tees are holding up well while others are headed for the trash heap/rag bag soon.

    • The range of quality in rayon fabrics is pretty amazing… I don’t mind a rayon woven, though I don’t really run across them very often…

  9. I like rayon challis. I’ve had good luck with it so far. But I’m not a fan of rayon jerseys. Too hard to sew with, and yes, lots of pilling. You should be a spokesperson for hemp fabric :) I’ve never sewn with anything hemp, but I’m still really interested in hemp silk after reading about your jacket.

    • Ha! I guess I am anyway, self-appointed… I just really like the fabric, and it seems like the hemp fabric industry is working hard to make “new” and more useful fabrics…. Which is good, I think.

  10. Kentucky legislature recently okayed farming hemp (not the smokable kind), so my friends with land that is now in pasturage are all excited to think they can make money growing and processing hemp rope and fabric. Cattle are expensive to raise. Hemp, not so much.

    • That’s awesome! It’s cheaper than cattle, to be sure, but it also enriches the land. And it’s a super useful plant. Way to go, Kentucky! :)

  11. What an interesting read! I remember the Tencel jeans and shirts of the 90’s – they looked so luxurious – I never bought any – they didn’t remain popular for long – wonder if that was because of some the issues mentioned. I have never seen rayon knit fabric for sale in Aus, but I am sure I have bought tops from Target that are poly/viscose. It’s probably the polyester pilling right? I have bought bamboo undies – and they are fine so far. Wouldn’t it be great if they could get it right as a more environmentally friendly option. Come on textile scientists!

  12. Hey Steph! I’m worming my way back to the online sewing community and slowly working my way through your posts. Expect a few comments on older posts! :)

    I wanted to comment because while I haven’t worked with any kind of rayon or bamboo jersey (that I know of), I have recently worked with woven rayon in my RTW-inspired blouse. I really loved the drape of the fabric, and while I did have to hang it for a bit before I did the hem, I haven’t noticed it growing at all (prob because it’s a woven). I love the way the top hangs, and I love the way it feels, but the wrinkles are awful. I basically have to iron it every single time I want to wear it, and sometimes half-way through wearing it. I guess having such a drapy design probably helps, because it doesn’t feel too hot on warm days at all, and I think I’d always only use this fabric on loose, drapy tops.

    But like I said, that’s only wovens. I don’t work with knits near as much as I should. :)

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  16. I had read somewhere that rayon was made from the mulberry trees the silk worms fed on. In the 90’s it was used for longer flowing dresses and it was recommended back then that if you sewed a dress or skirt with it (the woven type), that you let it hang overnight before hemming it. I like the feel and drape of it. I think I used to hand wash it in woolite, roll it in a towel to remove most of the water, then lay it on a rack to dry overnight.


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