LINOLEUM BACKING Until the early 1950s, linoleum was the dominant flexible floor covering. Linoleum typically consisted of one-third binder (oxidised soybean, linseed and tung oils, natural gums, and rosin), one-third inorganic fillers (pigments and ground limestone), and one-third organic fillers (ground cork and wood flour). The binder, known as cement, must be durable and resilient, yet thermoplastic. A highly oxidised and polymerising soybean oil worked well when compounded with rosin and other natural resins. However, floor coverings based on vinyl and phenolic resins or asphalt have now captured this market.