Textiles, Part 4: "Regenerated Fibers"

Hello, this time I'd like to write about "regenerated fibers," a type of synthetic fiber.

The previous article is linked at the bottom of the page, so please feel free to read it there.

In Parts 2 and 3, we discussed natural fibers, but from now on, we will be writing about synthetic fibers. First, let's take a look at the history of synthetic fibers.

They are now commonplace and inexpensive, so you can find them somewhere around you.

However, these synthetic fibers are relatively new, with a history of only about 100 years.

According to the Japan Chemical Fibers Association's "Chemical Fiber Booklet," the history of synthetic fibers follows this timeline:

1889: Successful manufacture of nitrified fiber

1892: Invention of "rayon" using the viscose process

1935: Invention of nylon 66

1939: Invention of vinylon

1940: Invention of polyurethane

1941: Invention of acrylic and successful manufacture of polyester

This is the history that synthetic fibers have followed. In 1889, the year Japan successfully manufactured its first synthetic fibers, the Meiji Constitution was promulgated.

The year 1941, when the now-common polyester was successfully manufactured, was also the year Japan declared war on Britain and the United States, marking the start of the Pacific War.

The polyester fibers we use every day today are less than 80 years old, let alone 100 years old.

Now, having left the history of synthetic fibers for a moment, let's move on to the topic of this article: "regenerated fibers."

"Regenerated fibers" are made by dissolving natural materials and regenerating them into fibers.

Recently, fibers made by melting down PET bottles are sometimes also called regenerated fibers.

Furthermore, according to "Easy-to-Understand Knowledge of Apparel Materials,"

In Japan, "synthetic fibers" often refer to these "regenerated fibers," sometimes distinguishing them from the later-developed "synthetic fibers."

Regenerated fibers are divided into "cellulose-based" and others.

Cellulose-based regenerated fibers include "rayon," "polynosic," "cupro," and "lyocell."

Other fibers include natural rubber, alginate fibers, and protein-based fibers.

Let's look at the characteristics of these fibers in order.

First, let's look at "rayon."

As mentioned earlier, rayon was one of the earliest synthetic fibers to be produced.

In Japan, production seems to have started in 1918, and it was used as a clothing material before and during the war.

It is made from wood pulp, which is dissolved in a liquid called viscose, then extruded through a nozzle to form fibers. The name rayon is said to originate from "ray" (shining) and "yarn" or "cotton."

The long fibers (filaments) of rayon are called artificial silk and have a silk-like luster and drape.

The short fibers (staples) are called "spun rayon," which is an abbreviation of "staple fiber." This name itself suggests that it was one of the first synthetic fibers to become widespread.

The characteristics of rayon include:

Excellent moisture absorption

Excellent drape

Significant decrease in strength when wet

These are some of the characteristics.

Next is "Polynosic."

This fiber is closer to cotton than rayon and is called high-strength rayon.

It is stronger than rayon and its strength reduction when wet is less than rayon.

It has more body and stiffness than rayon, and in that respect it can be said to be closer to cotton.

It is an intermediate fiber between rayon and cotton.

Next is "Cupro."

Cupro is a fiber made by dissolving short fibers remaining around cotton seeds, called cotton linters, in a copper ammonia solution and using wet spinning.

The name "Bemberg," a trademark of Asahi Kasei, is probably more well-known than "Cupro."

Its characteristics include:

Excellent moisture absorption and release

High dyeability

Superior strength, abrasion resistance, and durability compared to rayon

These are some of the characteristics.

Due to its excellent moisture absorption and release properties, it is often used for suit linings, etc.

Finally, let's talk about "Lyocell."

The raw material is the same wood pulp as rayon, and it is produced by dissolving it in an amine oxide-based solvent and spinning it.

Its characteristics include:

A soft texture and luster

Good drape

Excellent moisture absorption

Minimal reduction in strength when wet

These are some of its features.

"Tencel" by Tencel, a British company, is a trademark of this Lyocell fiber.

To briefly touch on other fibers:

Natural rubber, as the name suggests, is a fiber made from the sap of rubber trees.

Alginate fiber is a fiber made from seaweed such as kelp.

Protein-based fibers are fibers made from milk, corn, etc.

These regenerated fibers are decomposed by microorganisms, and therefore, compared to other synthetic fibers, they are environmentally friendly and sustainable materials that have been attracting attention in recent years.

Summary of this lesson

The history of synthetic fibers is relatively short, about 100 years.

Regenerated fibers are made by dissolving natural raw materials and regenerating them into fibers.

Rayon is one of the earliest synthetic fibers, using wood pulp as its raw material. Developed with silk as its target, it boasts excellent drape and dyeability. However, it has the weakness of losing strength when wet.

Polynosic is a fiber that closely resembles cotton, with less strength loss when wet compared to rayon. It also has more body and firmness than rayon, making it similar to cotton in that respect as well.

Cupro is a fiber made from the cotton linter, located near the cotton seed. Asahi Kasei sells it under the trademark Bemberg, and it is used in suit linings, etc.

Lyocell is a fiber made from the same wood pulp as rayon, and is soft, lustrous, and drapes well. Furthermore, its strength hardly decreases when wet.

Next time, I would like to write about "semi-synthetic fibers."

Thank you for reading this far.

Reference Materials

Aichi Prefectural Textile Promotion Association (2016) "TEXTILE HANDBOOK"

Teruhiko Ichimi (2014) "Easy-to-Understand Knowledge of Apparel Materials, Revised Edition" Seiunsha

Japan Chemical Fibers Association "Chemical Fiber Booklet" https://www.jcfa.gr.jp/about_kasen/knowledge/ebook/index.html

Etc.

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