Vulcanized fibre
Vulcanized fibre is a laminated plastic composed of only cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

. The material is a tough, resilient, hornlike material that is lighter than aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

, tougher than leather
Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...

, stiffer than most thermoplastics. The newer wood-laminating grade of vulcanized fibre strengthens wood laminations used in skis, skateboards, support beams and as a sub-laminate under thin wood veneer
Wood veneer
In woodworking, veneer refers to thin slices of wood, usually thinner than 3 mm , that are typically glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. They are also used in marquetry...



The British patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

 for vulcanized fibre was obtained in 1859 by the Englishman Thomas Taylor. He gained the patent after the introduction of celluloid
Celluloid is the name of a class of compounds created from nitrocellulose and camphor, plus dyes and other agents. Generally regarded to be the first thermoplastic, it was first created as Parkesine in 1862 and as Xylonite in 1869, before being registered as Celluloid in 1870. Celluloid is...

 in 1856 and before the invention of viscose rayon (regenerated cellulose) in 1894. In 1871 Thomas Taylor obtained the United States Patent for vulcanized fibre. The first organized industrial company to make vulcanized fibre, was the Vulcanized Fibre Company, incorporated first as a New York Corporation formed June 19, 1873 listed with William Courtenay President and Charles F. Cobby Secretary. The first N.Y. corporation was also found in the 1873 N.Y. City Directory which also listed William Courtenay President and Charles F. Cobby Secretary in 1873. From 1873 until 1878 the Vulcanized Fiber Co. had a New York office address of 17 Dey St., while the factory was located in Wilmington Delaware. This can be seen in the many advertisements that were placed in different publications at this time in history. A special charter was granted by the state of Delaware in 1873 until the Delaware corporation was finally incorporated on February 8, 1875 which now listed William Courtenay President and Clement B. Smyth Secretary.

In 1884 Courtenay & Trull Co. N.Y. was merged into the Vulcanized Fibre Co. which gave the company control over a new invention called by the trade name "Gelatinized Fibre".

On December 4, 1901, during a merger and consolidation the Vulcanized Fibre Co. changed its name to the "American Vulcanized Fiber Co." which was formed for the purpose of consolidating: Kartavert Mfg. Company, Wilmington, Delaware; American Hard Fibre Company, Newark, Delaware; Vulcanized Fibre Company, Wilmington, Delaware. and the Laminar Fibre Company of North Cambridge, Mass.

In 1922 the name was changed again when it was directly purchased by the National Fibre & Insulation Company of Yorklyn Delaware (who was also the owner of the Keystone Fibre Co.). The president of the National Fibre Company at this time was J. Warren Marshall, who took the same office after consolidating into the new company "National Vulcanized Fibre Company.

In 1965 the name was changed again to the NVF Company in order to avoid confusion over the years with a new and changing product line.

The water power of the Piedmont
Piedmont (United States)
The Piedmont is a plateau region located in the eastern United States between the Atlantic Coastal Plain and the main Appalachian Mountains, stretching from New Jersey in the north to central Alabama in the south. The Piedmont province is a physiographic province of the larger Appalachian division...

 streams in Northern Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...

 led to a proliferation of companies in the vulcanized fibre business. Over the years, these companies reorganized and merged. In 1922 National Vulcanized Fiber
National Vulcanized Fiber
NVF Company, formerly known as National Vulcanized Fiber, is a private company based in Yorklyn, Delaware. One of its original products, a sheet-like material called Forbon, is commonly used on guitar pickups...

 Company emerged as the main competitor to Spaulding Fibre, which had begun developing vulcanized products in Rochester, New Hampshire
Rochester, New Hampshire
Rochester is a city in Strafford County, New Hampshire, United States. As of the 2010 census, the city population was 29,752. The city includes the villages of East Rochester and Gonic. Rochester is home to Skyhaven Airport and the annual Rochester Fair....

 and Tonawanda, New York
Tonawanda, New York
Tonawanda may refer to:*Glacial Lake Tonawanda*North Tonawanda, New York, a city in Niagara County, north across Tonawanda Creek from the City and Town*Tonawanda , New York, consisting of the Town of Tonawanda less the Village of Kenmore...

, nearly a quarter century after the industry began in Delaware.

Some of the companies involved in vulcanized fibre development in the Wilmington region were the Nunsuch Fiber Company, American Hard Fiber Company, American Vulcanized Fibre Company, Continental Fibre Co., Diamond State Fibre Co., and Franklin Fibre Company. In the 1965 Post’s Pulp and Paper Directory, National Vulcanized Fibre Co. was listed as having two mills' producing rag paper for vulcanized fibre. They were at Newark, producing 15 tons a day; and Yorklyn, producing 18 tons a day. This compares with Spaulding Fibre’s Tonawanda plant, then producing 40 tons a day (Post’s directory). The competitors also produced bakelite, but marketed them under different names: Spaulding’s was Spauldite and National’s brand was Phenolite.


The process started with paper made from cotton rags. Before the processing of wood pulp and chemical wood pulps in the mid-19th century, the dominant fibre source for paper making was cotton and linen rags. The cotton rag sheet produced for conversion to vulcanized fibre is made like a sheet suitable for saturating. A paper is made for saturating by omitting any sizing additive, either beater added or surface applied. Today most paper sheets made for writing, printing, and coating have internal (beater
Hollander beater
A Hollander beater is a machine developed by the Dutch in 1680 to produce paper pulp from cellulose containing plant fibers. It replaced stamp mills for preparing pulp because the Hollander could produce in one day the same quantity of pulp it would take a stamp mill eight days to prepare.However,...

 added) sizing
Sizing or size is any one of numerous specific substances that is applied to or incorporated in other material, especially papers and textiles, to act as a protecting filler or glaze....

 provided by rosin
.Rosin, also called colophony or Greek pitch , is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black...

, alkyl succinic anhydride (ASA), or alkyl ketene dimer
Diketene is an organic compound formed by dimerization of ketene. Diketene is a member of the oxetane family. It is used as a chemical reagent in organic chemistry. It is a colorless liquid and heating regenerates the ketene monomer...

 (AKD) and surface sizing provided by starch. A sheet made for saturating would have none of those chemical ingredients. The unsized saturating cotton fibre paper prepared for vulcanized fibre would be passed through a vat containing a zinc chloride solution.

Zinc chloride

Zinc chloride
Zinc chloride
Zinc chloride is the name of chemical compound with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from...

 is highly soluble in water. The solution used in saturating the paper was 70 Baume in density (1.93 specific gravity) and about 110°F. This is roughly a 70% percent zinc chloride solution. Zinc chloride is a mild lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...

 with a solution pH of about 4. Zinc chloride can dissolve cellulose, starch, and silk. The zinc chloride used in making vulcanized fibre swelled and gelatinized the cellulose. The fibre swelling explains why paper filters cannot be used to filter zinc chloride solutions. It is also the reason why a number of paper plies were used to build up to the desired vulcanized fibre thickness, rather treating a single paperboard thickness. For instance, the practice was to use 8 paper plies of 4 mm thickness each, as opposed to a single paperboard ply of 32 mm.


Once the paper plies were saturated with the gelatinizing zinc chloride, they were pressed together. The pressing allowed intimate contact of the Cellulose fiber
Cellulose fiber
Cellulose fibers are fibres of cellulose from any source, either natural or manufactured.-Textile:In the textile industry regenerated cellulose is used as fibers such as rayon, . Cellulose fibers are manufactured from dissolving pulp...

s, thus promoting bonding between the cellulose chains. Once the bonding was established, the process of leaching out the zinc chloride from the vulcanized fibre could begin. The leaching (removal by diffusion out) of the zinc chloride was accomplished by subjecting the vulcanized fibre to successively less concentrated baths of zinc chloride. The rate at which this could occur was constrained by osmotic forces. If the rate at which the vulcanized fibre was subjected to lower and lower concentrations of zinc chloride solution were too rapid, the osmotic forces could result in ply separations. The final leaching bath concentration was 0.05% zinc chloride.Thicknesses up to 0.093”, can be made on continuous lines that stretch up to 1,000 feet (305m) in length.


For thickness above 0.093” and up to 0.375”, a discrete laminated sheet (similar in size (l x w) to plywood) was produced by the cutdown process. The cutdown sheets were racked and moved from vat to vat by overhead tracked cranes. Each vat was successively less concentrated until the desired 0.05% was reached. The thicker the material, the longer it took to leach the zinc chloride to 0.05%. For the thickest products, times of 18 months to 2 years were needed. The zinc chloride used in these processes was for the most part not consumed in achieving the desired bonding. Indeed any dilution of the zinc chloride resulting from the leaching was dealt with by using evaporators to bring the zinc chloride solution back to the 70 Baume needed for using it again for saturating. In a sense, zinc chloride can be thought of as a catalyst in the making of the vulcanized fibre.

Dried and pressed

Once the vulcanized fibre is leached free of the zinc chloride, it is dried to 5 to 6 percent moisture, and pressed or calendared to flatness. The continuous process-made vulcanized fibre could then be sheeted or wound up into rolls. The density of the finished vulcanized fibre is 2 to 3 times greater than the paper from which it starts. The density increase is the result of 10% machine direction shrinkage, 20% cross machine direction shrinkage, and 30% shrinkage in thickness.


The final product is a homogeneous nearly 100%-cellulose mass free from any artificial glues, resins, or binders. The finished vulcanized fibre has useful mechanical and electrical properties. It offers high tear and tensile strength, while in the thinner thicknesses allowing flexibility to conform to curves and bends. In thicker thicknesses, it can be moulded to shape with steam and pressure. One application for vulcanized fibre that attests to its physical strength is that it is the preferred material for heavy sanding discs. The electrical properties exhibited by vulcanized fibre are high insulating value, and arc and track resistance with service temperature of up to 110 to 120°C. Vulcanized fibre shows high resistance to penetration by most organic solvents, oils, and petroleum derivatives


  • Commercial Grade; standard grey, black or red, used for many applications such as washers, gaskets, gears, handles, etc.
  • Electrical Grade: high dielectric grey, 100% cotton, very flexible, (historically called fishpaper
    Fish paper or fishpaper is a strong, flexible, fibrous dielectric paper. It resists moderate heat and mechanical injury, and is often used for wrapping coils and insulating stove-top parts. It is hygroscopic and so must be treated with paraffin for use in moist environments...

    ), this grade is suitable for layer and ground insulation and has variations including top-stick grade used for wedges in small motors.
  • Trunk Fibre: Tough and abrasion resistant; used to surface steamer trunks, drum cases, wear and skid panels.
  • Bone Fibre: Exceptionally hard and dense, used for tight machining, tubing, pool cue ferrules (tips), cut out fuses.
  • Wood Laminating: Tough, multi-directional tensile and torsion strength, provides support and strength wherever wood laminations are used, particularly used under thin and exotic veneers as a stabilizer/strengthener.
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