Vulcanized fiber
Vulcanized fiber , also known as leather stone or cottonid , is a bio-composite material based on cellulose that has been known since 1855 . It was first manufactured industrially in 1859 by Thomas Taylor by soaking fibers with zinc chloride .
The name was derived from the vulcanization of natural rubber to hard rubber , which on the surface looks similar to the production of vulcanized fiber. In contrast, not rubber, but cellulose (formerly also jute fibers) is used as raw material for vulcanized fiber . Together with ebonite , celluloid and the casein plastic Galalith, vulcanized fiber is one of the oldest composite materials. Bakelite wasn't invented until 1909.
With the mass spread of plastics made from mineral oil since the mid-1950s, vulcanized fiber, mainly made from cotton, has been displaced from most of its earlier uses.
For the production of vulcanized fiber only cotton fibers are used which are incurred as by-products, waste or rejects from other production processes (clothing, cotton core cooking oil). The vulcanized fiber is therefore suitable as a material for sustainable recycling management.
Vulcanized fiber is a hard, tough , non-splintering, horn-like material that can be processed by bending , deep drawing, embossing / embossing , punching , cutting , drilling , milling , grinding , planing and gluing . The material density is 1.25 to 1.50 g / cm³, the maximum water absorption is 50% and the internal electrical resistance is approx. 200 megaohms. The maximum processing temperature should not exceed 180 ° C, the material is permanently temperature resistant up to 110 ° C, under oil up to 130 ° C. The material surface is smooth or structured, depending on the manufacturing and further processing process, and is insensitive to oils, fats, organic solvents and diluted acids and alkalis. Vulcanized fiber burns slowly and heavily in the flame with a yellow flame and a smell of burnt paper.
Manufacturing
Vulcanized fiber is made from vulcanized fiber base papers.
Technical cotton pulp is mainly used for these vulcanized fiber base papers, although smaller proportions of wood pulp can also be added for simpler qualities. The fiber material for the cotton pulp is based on rags (cotton rags) or linters (the short fibers on the seed core of cotton). The rags can be pre- (waste from cutting during clothing production) or post-consumer waste (used clothing collection).
Sequence of manufacturing processes
1. Production of cotton
2. Processing of cotton (textiles, cotton core edible oil production), with rags or linters as raw material for the cotton pulp.
3. Processing of rags or linters into technical cotton pulp ("cotton rag pulp" / CRP or cotton rag based dissolving pulp) in the pulp mill.
4. Processing of the cotton pulp into vulcanized fiber base papers in the paper mill.
5. Processing of the vulcanized fiber base papers into vulcanized fiber in the vulcanized fiber factory.
6. Processing of the vulcanized fiber into consumer goods (grinding disks, sealing rings, etc.) or components of consumer goods (e.g. in the furniture industry) at the manufacturer of consumer goods.
During the manufacture of vulcanized fiber, several (6-10) layers of vulcanized fiber base papers of different quality are brought together over guide rollers from a roll and pulled together through a parchment bath, whereby the surface of the individual fiber is loosened; So-called hydrate cellulose forms on the surface . In this state, the paper pulp is drained (squeezing off the liquid) and the individual fibers and individual paper webs are connected to one another. Without the addition of further binders , an almost homogeneous mass of hydrate cellulose is created. The fiber quality and the setting of the parchment determine the quality of the vulcanized fiber.
With the appropriate experience, you can use the variation options to produce vulcanized fibers of the most varied of quality and thus optimally adjust their properties to specific areas of application.
Two different methods are used in practice today. One is the zinc chloride process. It is produced by soaking it with a nearly concentrated 75 ° C hot zinc chloride solution, which, however, can lead to zinc chloride residues in the material.
The sulfuric acid process is just as important industrially . The process of the more difficult production process is similar here, but instead of zinc chloride, sulfuric acid is used as a parchment agent, which is completely removed from the material and therefore leaves no detectable traces. The consequences are therefore a particular environmental friendliness in connection with increased mechanical properties.
The parchment agent acts as a catalyst in both processes and is recovered.
properties
Vulcanized fiber is characterized by the following properties:
- high mechanical strength
- relatively light weight
- good electrical insulation
- spark-extinguishing
- burning heavily
- antistatic
- insensitive to oils, fats, diluted acids and alkalis
- high stability
- good elasticity
- good sliding properties (e.g. slide rails for drawers)
- pleasant, warm feel
application
In the past, vulcanized fiber was used instead of leather and rubber to make suitcases (smooth, hard, reddish-brown, relatively waterproof), belts, gears , brake pads , buttons , visors, harness handles and bandages for trolley rollers.
Modern application examples include:
- Backing material for abrasives on substrates (e.g. grinding wheels )
- Stamped parts for mechanical applications
- Deep-drawn molded parts (e.g. case shells, welding masks)
- Electrical insulation material
- Stamped parts for seals
- Release film for the production of polyester laminates
- Carrier for continuous laminates
- Carrier for plastic decorations based on melamine resin
- Support layer for real wood veneers and deep-drawn surfaces
- Knife handles for sports and collector's knives
- osmotic membranes
- Roller covering in spinning mills
- Top and bottom of bobbins in pickups for electric guitar and electric bass
Web links
https://www.hornex.de/html/produkte/vulkanfiber/produktion.html
https://www.dynos-gmbh.de/dynos/produktion/
https://sachsenroeder.com/vulkanfiber_savutec/herstellungsprozess/
https://www.hoffsuemmer.de/de/spezialpapiere/industriepapiere/
https://cordier-paper.de/produkte/technische-papiere/technische-papiere/?slide=0
https://hokuetsu-toyofibre.jp/vf_manufacturing_method_e/
Individual evidence
- ↑ The Bounty of the Piedmond streams: Industries Supported by Water Power in Northern Delaware. (PDF; 205 kB) pp. 4–8.
- ↑ Domininghaus plastics: properties and applications. 7th edition. Springer, Berlin 2007, p. 1313.
- ↑ VDI agricultural engineering group; Conference on agricultural machinery made from improved and new materials, 29. – 31. October 1962, Cologne
- ↑ Sachsenröder: SAVUTEC manufacturing process