The difference between top grain leather sofas and bonded leather sofas is more than just price. Top grain leather sofas are expensive, but they're also one of the highest grades of leather upholstery available. Bonded leather sofas cost significantly less in comparison, because bonded leather is made of scraps of leather and other less expensive materials.
About Leather Upholstery
Leather used to upholster a sofa is typically made from cowhide that has been buffed or sanded and tanned to provide a soft, durable covering. The hides are split into at least three layers: The uppermost layer is refinished to remove imperfections and sold as top grain leather, and the lower layers that require more refinishing and treatment are sold as split leathers. Pieces not useful for any of these first few grades are mixed with a bonding agent, or glue, and heated and rolled to make bonded leather.
Top Grain Leather
Sofas made of top grain leather are made with material taken from the top layer of hides that are sanded and then tanned before being cut to cover the sofa. Sanding the leather removes scars, branding marks and scrapes that are often present in this layer of hide. Top grain leather upholstery may be of different grades, depending on the amount of sanding and surface preparation required to remove blemishes and to meet quality standards. A cheaper top grain leather sofa typically is one that has required extensive refinishing to correct imperfections.
Bonded leather used on sofas and other furniture is typically blended with polyurethane or vinyl and then given a fabric backing and a final layer of latex mixed with leather pieces. Bonded leather sofas are not often considered to be a leather product at all because they contain only between 10 and 17 percent genuine leather, and very little or none of this is in the surface material. The surface material that you see is often polyurethane that has been stamped to give it a leather look. Bonded leather sofas are essentially a polyurethane product with leather grains sprayed onto the backing.
Bonded leather sofas will last about five years and are easier to spot clean than top grain leather sofas. Considered one of the toughest leather upholsteries available, top grain leather will keep its appearance for up to 15 years or more with proper care. Because it doesn't go through a tanning process, bonded leather contains low levels of formaldehyde and is more ideal for those with leather allergies. It is also more affordable than top grain leather sofas.