Vulcanized fibre

Vulcanized fiber, also known as stone or leather Cottonid, is a well-known since 1855 composite material based on cellulose. It was first time in 1859 by Thomas Taylor ( not to be confused with the writer Thomas Taylor) produced industrially by impregnating fibers with zinc chloride.

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The name was inspired by the vulcanization of natural rubber to hard rubber, similar to the production of vulcanized fiber superficially. In contrast, however, are used as raw material of paper fibers, including jute used. Vulcanized fiber belongs together with ebonite, celluloid and casein plastic galalith of the oldest plastics; Bakelite was invented in 1909. The vulcanized fiber is due to their special characteristics and increasingly demanded use of materials based on renewable resources excellently as a modern composite material.

Vulcanized fiber is a hard, tough, non-splintering, horn -like material that can be processed by bending, stamping / embossing, punching, cutting, drilling, milling, grinding, planing and gluing. The material density is from 1.25 to 1.50 g / cm ³, the absorption of water is a maximum of 50 %, and the internal electrical resistance is approximately 200 Megaohm. The maximum processing temperature should not exceed 180 ° C, the material is durable temperature resistant up to 110 ° C, under oil to 130 ° C. The material surface is insensitive, depending on the manufacturing and finishing process smooth or textured, and to oils, fats, organic solvents and dilute acids and alkalis. In the flame, vulcanized fiber burns slowly and painfully with a yellow flame and a smell of burnt paper.

Production

In the preparation of vulcanized fiber will be processed as the raw material webs of cotton and / or cellulose fibers.

The paper webs through a Pergamentierbad, wherein the surface of each fiber is partially dissolved; on their surface, so-called Hydratzellulose forms. In this state, the paper pulp couched ( pressing of the fluid), while the individual fibers to each other as well as single paper sheets is connected. Without the addition of more binder an almost homogeneous mass of hydrate cellulose. The fiber quality and the setting of Pergamentierung determine the quality of vulcanized fiber.

With appropriate experience, you can use the variations to produce vulcanized fiber of different quality and therefore optimally adjust their properties to specific applications.

Nowadays in practice two different methods are used. One is the zinc chloride method. The production is done by soaking in concentrated almost 75 ° C hot zinc chloride solution, however, which can lead to residues of zinc chloride in the material.

Industrially just as important is the sulfuric acid method. The sequence of the diffizileren production process here is similar, but sulfuric acid is used as parchmentisation, but which is discharged completely from the material and thus leaves no detectable traces instead of zinc chloride. The consequences are, therefore, an environmental excellence in conjunction with enhanced mechanical properties.

Parchmentisation the method works both as a catalyst and is recovered.

Properties

Vulcanized fiber is characterized by the following properties:

• High mechanical strength
• Relatively low weight
• Good electrical insulation
• Spark -extinguishing
• Heavy burning
• Antistatic
• Resistant to oils, greases, diluted acids and alkalis
• High stability
• Good elasticity

Application

Previously vulcanized fiber was also instead of leather and rubber to manufacture of luggage ( smooth, hard, red-brown, relatively waterproof), belts, gears, brake pads, buttons, cap umbrellas, kitchenware handles and harnesses for car wheels.

Modern examples include:

• Substrate material for coated abrasives (eg grinding wheels )
• Stamping parts for mechanical applications
• Insulating material
• Stamping parts for seals
• Release film for the production of polyester laminates
• Support for continuous laminates
• Carrier for plastic pattern on melamine resin base
• Support layer for real wood veneers and deep drawn surfaces
• Osmotic membranes
• Roller cover in spinning mills
• Top and bottom of coil bobbin with pickups for electric guitar and electric bass