Liming - Hint 1

TFL's Beamhouse auxiliaries minimise grain "draw" and protect the value of the hide.

The liming process removes the hair/ epidermis and at the same time swells the hide or skin to "open up" the fibre structure. This requirement is today met by a relatively quick process in which the destruction of the hair and epidermis is carried out by sodium sulphide, and lime provides a reserve of alkali to swell the structure and modify the fibres.

The problem with this apparently simple process is that the chemicals have to work from a float and so the outer layers of the skin or hide are influenced by the alkali first and start to swell while the inside structure has not yet been penetrated. Thus the grain swells but because it is attached to the inside structure which at this point is not yet swollen and is not increasing in area, it has to wrinkle and produce the well known problem of lime draw. Too much swelling of the grain layer too soon will also trap hair roots and produce dirty, scuddy limed pelt.
Liming auxiliaries may be used to advantage in controlling this swelling thus allowing the hide or skins to be gently swollen for opening up but at the same time allowing the liming media to diffuse evenly through the pelt. This type of system not only produces less draw but also advantages in yield and reduced growth marks.

This means more cutting area particlularly important for upholstery leathers.

Processes

• Beamhouse

Industries

• Garment
• Upholstery
• Automotive
• Shoe