Linoleum

Linoleum is a floor covering made from materials such as solidified linseed oil (linoxyn), pine resin, ground cork dust, sawdust, and mineral fillers such as calcium carbonate, most commonly on a hessian or canvas backing. Pigments are often added to the materials to create the desired color finish. Due to the pigment being mixed directly into the linoleum cement, the finished color of the tile remains visible even after years of wear. In the past some of these pigments were iron oxide, red lead or lithopone.[1]

It gained popularity as a beautiful and easy to clean flooring option in the late 19th century and is still used today. Commercially, the material has been largely replaced by sheet vinyl flooring, a plastic alternative made of polyvinyl-chloride, though many still call it linoleum. This is mainly due to the fact that its plastic counterpart is less costly and much faster to produce.[2]

The finest linoleum floors, known as "inlaid", are extremely durable, and are made by joining and inlaying solid pieces of linoleum. Cheaper patterned linoleum comes in different grades or gauges, and is printed with thinner layers which are more prone to wear and tear. High-quality linoleum is flexible and thus can be used in buildings where a more rigid material (such as ceramic tile) would crack.

Chemistry

Linoleum in essence consists of two components, a polymerized organic compound and a collection of fillers, pigments, and catalysts. The polymerized precursors are rich in polyunsaturated fats, especially derivatives of linoleic acid and alpha-linolenic acid. Such fats are called drying oils because they "dry" (harden) upon exposure to the oxygen in air.[3] The drying process results in cross-linking of the fat molecules. This cross-linking process is often slow, thus catalysts and heat are applied to give a durable material. During this cross-linking, fillers and pigments are mixed with the resin.

Sustainability

Linoleum is a sustainable choice when looking for flooring options in comparison to many other plastic alternatives. It is created from multiple renewable resources that are non toxic and fully biodegradable, not to mention it is very durable and will last at least 20 years, if not longer if maintained correctly.[4]

This means that linoleum's ecological footprint is very small in comparison to many other material choices on the market. Linoleum is considered an environmentally friendly alternative to PVC as it is derived from renewable, natural, biodegradable material.[5] Many companies that manufacture linoleum sheets have environmental certifications such as some of the leading brands Artoleum and Marmoleum.[6][4]

Furthermore, off-cuts created during the manufacturing process are fully recyclable and can be ground or cut up and mixed into new batches of the linoleum cement.

History

Linoleum was invented by Englishman Frederick Walton.[7] In 1855, Walton happened to notice the rubbery, flexible skin of solidified linseed oil (linoxyn) that had formed on a can of oil-based paint and thought that it might form a substitute for India rubber. Raw linseed oil oxidizes very slowly, but Walton accelerated the process by heating it with lead acetate and zinc sulfate. This made the oil form a resinous mass into which lengths of cheap cotton cloth were dipped until a thick coating formed. The coating was then scraped off and boiled with benzene or similar solvents to form a varnish. Walton initially planned to sell his varnish to the makers of water-repellent fabrics such as oilcloth, and received Patent No. 209 on 27 January 1860[8] for the process. However, his method had problems: the cotton cloth soon fell apart, and it took months to produce enough of the linoxyn. Little interest was shown in Walton's varnish. In addition, his first factory burned down, and he suffered from persistent and painful rashes.

Walton soon came up with an easier way to transfer the oil to the cotton sheets, by hanging them vertically and sprinkling the oil from above, and he tried mixing the linoxyn with sawdust and cork dust to make it less tacky. In 1863, he applied for a further patent, which read: "For these purposes canvas or other suitable strong fabrics are coated over on their upper surfaces with a composition of oxidized oil, cork dust, and gum or resin ... such surfaces being afterward printed,

Manufacturing

Walton also tried integrating designs into linoleum during the manufacturing stage, coming up with granite, marbled, and jaspé (striped) linoleum.[16] For the granite variety, granules of various colors of linoleum cement were mixed together, before being hot-rolled. If the granules were not completely mixed before rolling, the result was marbled or jaspé patterns.

Walton's next product was inlaid linoleum, which resembled encaustic tiles, in 1882. Previously, linoleum had been produced in solid colors, with patterns printed on the surface if required. In inlaid linoleum, the colors extend all the way through to the backing cloth. Inlaid linoleum was made using a stencil type method where different-colored granules were placed in shaped metal trays, after which the sheets were run through heated rollers to fuse them to the backing cloth. In 1898, Walton devised a process for making straight-line inlaid linoleum that allowed for crisp, sharp geometric designs. This involved strips of uncured linoleum being cut and pieced together patchwork-fashion before being hot-rolled. Embossed inlaid linoleum was not introduced until 1926.

In its earlier days most linoleum was produced by hand with basic equipment but by the 1880s new manufacturing machinery was introduced that streamlined the process. These new machines were the flat-bed printing machine and rotary device.[17] This process has evolved since and some of the longer parts of the process that once took weeks to complete, can be produced from start to finish in about seven days.[18]

Use

Between the time of its invention in 1860 and its being largely superseded by other hard floor coverings in the 1950s, linoleum was considered to be an excellent, inexpensive material for high-use areas. In the late nineteenth and early twentieth centuries, it was favored in hallways and passages, and as a surround for carpet squares. However, most people associate linoleum with its common twentieth century use on kitchen floors. Its water resistance enabled easy maintenance of sanitary conditions. Furthermore, the oxidization process of linseed used in the fabrication of Linoleum creates a Lynoxin binder which is naturally bactericidal. This creates a natural defense against harmful germs which is why Linoleum flooring is a popular choice in high bacterial areas such as schools, hospitals, kitchens and day cares.[19]The heavier gauges of linoleum are known as "battleship linoleum", and are mainly used in high-traffic situations like offices and public buildings. It was originally manufactured to meet the specifications of the U.S. Navy for warship deck covering on enclosed decks instead of wood, hence the name. Most U.S. Navy warships removed their linoleum deck coverings following the attack on Pearl Harbor, as they were considered too flammable. Use of linoleum persisted in U.S. Navy submarines.) Royal Navy warships used the similar product "Corticine".

Further reading

External links

• Dominion Oilcloth and Linoleum Company illustrated catalogue, 1926
• Historic linoleum materials in the Staten Island Historical Society's Online Collections Database