Environment Friendly Artificial Leather

Description And Advantages

Researchers in Japan have developed a new eally friendly process for making artificial leather which does not involve the use of organic solvents. The new leather has a composite fiber and polyurethane structure that comes much closer than previous materials to the structure of natural leather. It achieves this by employing a manufacturing method that impregnates a specially fine-structured, high-density nonwoven fabric with a unique moisture-dispersing polyurethane that solidifies quickly. The resulting material has outstanding processing ability and wearability and is moisture repellant.

Developed by Osaka-based Teijin Ltd., the new artificial leather, called Loele, has an excellent processability in comparison to that of previous artificial leathers made using organic solvents. It is a specially fine-structured, high-density nonwoven fabric that uses a conjugate yarn made from two kinds of polymers.

The use of moisture-dispersing polyurethane creates a product that is much kinder to the environment than previous artificial leathers where organic solvents such as DMF (dimethylformamide) were required during manufacture. It also has a soft feel.

The new material realises a structure close to that of natural leather by utilising a manufacturing method that solidifies the material in a short time through impregnating a high-density non-fiber fabric with special moisture-dispersing polyurethane. The material is then heated to crystallise the polyurethane between the fibers.

Compared with previous manufacturing methods, the amount of electric energy and steam required for processing is much less, and the amount of carbon dioxide discharged per unit area is around one-third that of previous methods.

The amount of organic solvents and denatured products discharged is less than one-tenth the volume required for manufacturing other artificial leathers. Due to the use of special polyurethane that has water-dispersing abilities, the amount of organic solvents used in processing has been reduced to nearly zero.

Due to the homogenous and fine structure of Loele, the material's Leather Feel Index - that is the measure of suppleness and handle strength - has been improved two times over previous artificial leathers.

Loele's splitting strength is outstanding, maintaining the same values as previous artificial leathers made using organic solvents.

Application

The use of leather sheet materials is growing worldwide. It is used in a variety of fields including shoes, apparel, furnishings and automobiles. The amount of natural, artificial and composite leather used annually is estimated to total 1.6 billion square meters. Artificial leather was first created in the USA in 1963 and was later introduced to Japan. Until the 1970s, artificial leather was considered an alternative to genuine leather, and in the 1980s it was considered healthier and cleaner than the real thing.

Source

PTI Science Service, November 16-30, 2000,