April 15, 2005


Ancient Japanese Paper-making Techniques Alive in the Information Age

* This article is under copyright protection.

Manabu Akaike
Universal Design Intelligence Inc.

Thousand Year History of Tosa Washi Paper-making

The etymology of the word "paper" lies in the Egyptian word "papyrus," but paper is actually believed to have originated about two thousand years ago in China. Remains of a hemp paper have been recovered from tombs that date between 202B.C. and A.D.8. That paper appears to have been made of fragments of fiber left suspended in water used in the process of spinning thread out of cotton and flax, that were then dried into a paper material. Refinement of that manufacturing process took place between A.D.25 and A.D.220, resulting in the creation of paper-making techniques that are the foundation of the paper-making technology we use today. Hemp and bark were pounded to produce long fibers which were then released into vats of water. Hydrogen bonding of the cellulose molecules takes place, causing the fibers to pull against each other. The pulpy mixture is then scooped out onto flat mesh molds and the water drained off, then the material is peeled off the mesh and laid on a plank or other flat surface to dry.

This paper-making technique was fully established in Japan by the year 610. Subsequently, the addition of glue-like plant mucilage to the plant fiber solution led to the "nagashi-suki" method, where the solution is skillfully shaken on the mesh and excess water streamed off in order to better disperse the long fibers. This technique gave rise to the uniquely beautiful and resilient Japanese paper known as washi.

The three shrubs used as the raw plant fiber in washi paper, namely the kozo (paper mulberry), mitsumata (Edgeworthia papyrifera), and gampi (Wikstroemia sikokiana), are suited best by warm climates with heavy rainfall, and still today 50% of these shrubs are produced in Shikoku's Kochi Prefecture. Kochi is also blessed with the clear streams and soft water needed for washi making. These natural conditions have carved out the thousand year tradition of Tosa washi paper-making.

One of the most well-known of the Tosa washi papers is Tengu-joshi. Extremely thin, of a uniform gossamer-like thickness, yet very strong and accepting of ink, tengu-joshi was widely exported to America about seventy years ago as typewriter paper. During the special manufacturing process, the fibers in tengu-joshi become intertwined in complex vertical, horizontal and diagonal patterns. This is the process that developed later into the non-woven textile technology that is used in so many industrial applications today. And the independent operator that brought the potential of this Tosa washi to become the "paper beyond paper" to the information technology market, was born of the same region.

Japan Brings First Duplex Condenser Paper to the World

The company that gave rise to the high performance paper that can boast of a 70% world share is Nippon Kodoshi Corporation (Japan High-Grade Paper Corporation, or NKK). Its famous electrolytic capacitor paper supports cutting edge electronics technology and is a high grade industrial paper unparalleled in the world today.

Nippon Kodoshi was originally founded in 1941 for the express purpose of commercializing a patented technology for viscose-processed paper (viscose is material used in cellophane). The Tengu-joshi paper had been widely exported to America just prior to that the time saw export volume drop off precipitously along with the deterioration of Japanese-American relations in the 40s. NKK president Hiroshi Seki looks back at that period in the company's history.

"At that time, handmade or tesuki washi paper was a cottage industry, and it was a terrible thing to see these families lose this major money-maker. To help them, people from both industry and academia gathered together to cooperate in developing new applications for this tengu-joshi paper. What was born as a result was a new high performance paper that used viscose-processing to make it highly permeable, but so strong that it wouldn't tear even when soaked. We called it "kodoshi," or high-grade paper. We developed products using it as a substitute for wood pulp of which there was a shortage at the time, including bags for preparing kampo Chinese herbal medicines and paper handkerchiefs."

Electrolytic capacitor paper is soaked in electrolytic fluid and used as a protective wrapping to avoid direct contact of the anode and the cathode. The paper handkerchief that could be soaked through and still not tear soon garnered attention for this market niche, and in 1961, Japan became the first country in the world to introduce the use of duplex condenser paper to the world. The duplex paper developed by Nippon Kodoshi was based on new paper-making machinery that combined the machinery used to make machine-made high-density writing paper with that used to make low density washi paper. The paper made by each of these machines would be soaked and then pressed together in two layers and dried. Without use of any adhesive, the two layers would adhere completely to form a single sheet. This duplex paper is used as a separator in alkaline batteries, and in fact is used in almost all the alkaline batteries made in Japan. This paper has also been adopted for use by Toyota Motor in its popular Prius eco-car as a component of the electrolytic condenser in the inverter that controls the energy source and engine.

JAPAN CLOSE-UP, February 2003, published by PHP

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