FreeShip- Rayon Fiber (Flocking), Royal Blue, Epoxy Resin Thickener, Thixotropic Agent- (Prompt rebate on orders with 3+ FreeShip items!)

DESCRIPTION-> Click "Learn more about this item" for article & instructions!
****************
The 2nd picture close-up shows the thinness of the individual fibers; these are extremely "tight tolerance" fibers, the diameter and grooving are very consistent from fiber to fiber, and they are also very straight (unless forcibly bent by heavy loading in resin).
If you wish to use these fibers for flocking, there are complete instructions for flocking in articles and videos on the web. Here is one: https://www.flockingunlimited.com/pages/how-to-apply-flocking

The flock in this listing is made of rayon, which is a very interesting polymer.
Normally I put non-technical information further down in the description (actually, you will find the simple "how-to" section in the step-by-step flocking instructions that are given in the site link above).
But here is a bit of first hand info gained by pulling out the microscope and getting a closer view of the tiny rayon fibers. Rayon fiber is unique and different from other fibers like the olefins (polyethylene and polypropylene being the most common) or cotton.
If you look at this rayon's fibers under a microscope they are very thin, transparent fibers that have very smooth axial (lengthwise) surfaces. There are no perpendicular bumps or fibrous outcroppings, so they slide past each other with low friction. They are also striated lengthwise which reveals a radial (cross-sectional) shape that has very regular rounded grooves that are made by the spinneret's hole (the die through which the rayon solution passes to become a fiber). This circular grooved cross section (versus a regular circular hole cross section) increases the surface area of the fiber, making the fiber stronger and giving it other properties according to which grade it is. The many grades of rayon have intermediate chemicals which can degrade a common steel spinneret. Rayon is the only polymer which requires an exotic and expensive platinum alloy spinneret. This thin rayon is about 1/32" in length and is the shortest fiber we have. "Milled" glass fiber is often thought to be the shortest fiber at about 1/16" in length.
I've read some sources that say that rayon is a relatively low strength polymer. The particular rayon fibers we carry don't bear that out. Perhaps if the rayon was in a smooth, completely round cross section the fiber would be weaker. The mechanical advantage of having perfect longitudinal grooves might be having a larger effect on stiffness and strength than would be expected.

I bought rayon fiber for a non-flocking experiment and so I wanted a neutral white. Fiber for flocking is made from several types of polymer fibers. Rayon has several advantages as a flocking fiber. It comes from a natural polymer, cellulose (usually from cotton or wood). It has physical properties which make it a good flocking fiber. Another interesting thing about rayon is that it's used as a "precursor" in the manufacturer of high tech carbon fiber, now used in many products for it's strength and light weight. Aerospace and sporting goods are prime areas of application.
Rayon (the most common grade being "viscose") comes in many colors. It's used mostly as a fabric. There are many grades of it having different physical properties. Rayon is somewhat elastic (stretches). It has a grade type-range of fibers meant to match silk, cotton, wool, etc. It has a specific gravity (SG, density) of 1.52, which is fairly high compared to other man-made, polymer fiber materials (polypropylene has an SG of 0.90, and nylon has an SG of 1.14. That means that if you add a certain amount by weight of those polymer fibers, you're going to be adding a larger volume of the polypropylene and nylon than you are of rayon.
This grade of rayon has very good properties for flocking if you want to try flocking. The individual fibers tend to stay separate and straight, and not clump together like cotton, polypropylene, and others. The fibers are the thinnest of any fiber we sell and the shortest. Those properties also make it more free flowing than other fibers. Rayon bears some resemblance to nylon fiber when looked at with a microscope. Nylon also tends to be of regular cross section (round, but not grooved), straight, and transparent. Nylon fiber, though, tends to clump together and has a somewhat larger diameter. It is also more flexible (the grooves in rayon fiber would tend to add to their flexural strength). It should be noted that the shortest nylon I've ever tried is 1/8th inch long (the shortest I could find), which may have a contributing effect on "clumpy-ness". Nylon doesn't cause a resin to become thixotropic when loaded with the same volume of fiber as rayon.
Because these fibers tend not to clump, they will stay more discrete when they are sprinkled (or sprayed with a flocking sprayer) and they will settle evenly on the adhesive or paint coated object you're flocking. You don't want bumps and dips of flock, you want it to look like smooth and even like velvet. You can buy the materials for flocking at many online sources. Here's one that shows a picture of the sprayer (and some flocking and adhesive):
{ https://www.constantines.com/miniflocksprayer.aspx }.

I was testing fibers that would work well in plaster and gypsum cement, acting as a reinforcing fiber at a low loading percentages, while still allowing the plaster to flow. I also wanted to be able to increase viscosity by adding more fibers into a shape holding paste at higher loadings while not turning into a "stringy" paste as most longer and thicker fibers do when added to plaster or gypsum cements (fibers like nylon, glass, cotton, or polyethylene or polypropylene).
What I found is that it acts as a thixotropic agent (when in motion, like pouring or being vibrated, it flows easily; when at rest it does not flow). You can add much higher percentages than other fibers like nylon and it will not greatly increase viscosity. When added in relatively large amounts it produces a paste that is less fibrous than other larger fibers (as expected), but it is softer and weaker. It does not appreciably increase strength at medium loading, probably because of the thinness and shortness of its fibers. That experiment shows it has limited benefits when used in plaster and gypsum cement, beyond imparting thixotropy.

I thought I should try the rayon fibers with a resin like epoxy. It might be expected to make thin films of resin stronger yet not appearing fibrous because of its thinness. Not wanting to wait for my low viscosity, slow curing epoxy to cure, I tried it with my medium viscosity, fast curing epoxy. I tried 5% rayon by weight to total epoxy (first mixed in the resin side before adding the hardener). It had a pronounced thixotropic effect. When stirring it acted like a slightly more viscous mix, but still easily flowing. After sitting still for a brief time and then slowly tipping the cup it did not flow. It also had an unusual type of 'stringiness'. It 'stretched' out into a thin layer bridging from side to side of the cup while stirring, exhibiting stringiness in a very fine and smooth form (as predicted above), not at all what you'd get from adding milled glass (very short thin glass fibers). I poured it out onto a ziplock bag in a strip of variable thickness. After being fully cured at 100F, it was stronger and more flexible, especially in thinner sections. I think making an epoxy film with a lower viscosity and longer curing time with various loadings of fiber would be a worthwhile experiment.
The probable reasons for this rayon/epoxy's behavior would likely be a combination of this rayon's thinness, the flexibility of the rayon polymer, the high smoothness and grooving of the surface of the rayon fibers, and simply the percentage of fiber added. I believe the longitudinal grooving tends to orient the fibers like pieces of a jigsaw puzzle, close fitting and "locked" together which would add strength, while the flexibility of rayon would add to the overall flexibility of the epoxy/rayon mix (ordinary unmodified epoxy in thin sections tends to be stiff and easily broken. Other factors I'm unaware of are of are no doubt contributing.

Rayon was one of the first polymers ever made. Several early polymers have their roots in cellulose which is a very commonly found material in plants and trees. Depending on which source you consult, you'll get different answers to "What was the first plastic". Some sources say "bakelite" (1907) was first (and it was the first synthetic polymer, meaning all compounds used to make it were artificial). One source says the first naturally derived plastic was "celluloid" (1869), which combined cellulose and camphor. But predating celluloid was "nitrocellulose", (a combination of cellulose and nitric acid) going all the way back to 1832. Early versions were not practical because of its predisposition for instability and exploding (!), depending on the amount of nitrification. Later it was stabilized and is still used today, mainly in lacquers. Although no longer explosive it is very flammable. In 1855 nitrocellulose was modified to be soluble in organic solvents and the first "rayon" was produced.
The Wikipedia article on rayon good, and here are some excerpts:
{ https://en.wikipedia.org/wiki/Rayon } :
"Rayon is a manufactured fiber made from regenerated cellulose fiber. The many types and grades of rayon can imitate the feel and texture of natural fibers...types that resemble silk are often called artificial silk.
Since rayon is manufactured from naturally occurring polymers, it is not considered to be synthetic. Technically, the term synthetic fiber is reserved for fully synthetic fibers. In manufacturing terms, rayon is classified as "a fiber formed by regenerating natural materials into a usable form". Specific types of rayon include viscose, modal and lyocell, each of which differs in manufacturing process and properties of the finished product. Rayon is made from purified cellulose, harvested primarily from wood pulp, which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in fibers of nearly pure cellulose......
Rayon is a versatile fiber and is widely claimed to have the same comfort properties as natural fibers, although the drape and slipperiness of rayon textiles are often more like nylon. It can imitate the feel and texture of silk, wool, cotton and linen. The fibers are easily dyed in a wide range of colors. Rayon fabrics are soft, smooth, cool, comfortable, and highly absorbent, but they do not insulate body heat, making them ideal for use in hot and humid climates, although also making their "hand" (feel) cool."

Rayon is not considered toxic, hazardous, or flammable. It is combustible (it takes a sustained higher heat source to flame; flammable means it can ignite and burn at lower temperatures which do not have to be sustained). Individual fibers are very light and like all airborne dust inhalation should be avoided. Wear a dust mask if you are using it for flocking

=======================================================================