Here's the definition of bonded leather from Wikipedia...
"Bonded leather is made by shredding leather scraps and leather fiber, then mixing it with bonding materials. The mixture is next extruded onto a fiber cloth, or paper backing, and the surface is usually embossed with a leather-like texture or grain. Color and patterning, if any, are a surface treatment that does not penetrate like a dyeing process would. The natural leather fiber content of bonded leather varies. The manufacturing process is somewhat similar to the
production of paper.
[1]
Lower-quality materials may suffer flaking of the surface material in as little as a few years, while better varieties are considered very durable and retain their pattern and color even during commercial use.
[1] Because the composition of bonded leathers and related products varies considerably (and is sometimes a
trade secret), it may be difficult to predict how a given product will perform over the course of time. There is a wide range in the longevity of bonded leathers and related products; some better-quality bonded leathers are claimed to be superior in durability over low-quality genuine leather.
[2]"