Tanners convert the raw hides and skins into leather. At its simplest,leather is hide or skin which has been treated so that it will not decay,and will last for hundreds of years. Every hide and skin is unique,and varies not only from species to species,b...[繼續(xù)閱讀]

    After retanning,dyeing and fatliquoring,the leathers are horsed up overnight to allow excess liquor to drain off. Then the leathers are sammed and set out to reduce the water content further. At this stage,the leather still contains about 50%-60% water. T...[繼續(xù)閱讀]

    6.1 The Concept of Wet White Process The wet white process was first recommended as long ago as the early 1980’s. Since its initial introduction to the leather industry a number of chemical companies have developed materials for use as wet white pretannin...[繼續(xù)閱讀]

    Practical unhairing systems are mainly based on the use of sulfide or enzyme as sharpening agents. The sulphide unhairing methods and enzyme unhairing methods are used in almost all the processes of leather manufacture.2.1 Sulphide UnhairingLime-sulphide ...[繼續(xù)閱讀]

    Fresh hides or skins consist of water,proteins,fatty materials,mineral salts and some other substances. In all these constituents,the proteins are important for leather making. These proteins are collagen,keratin,as well as elastin,albumen,globulin,mucins...[繼續(xù)閱讀]

    Sheepskins and some of other small skins contain large amounts of natural fat. As already mentioned,sheepskins contain up to 30% fat which has to be removed. Excessive amounts of fatty substances in the skin may interfere with uniform penetration of tanni...[繼續(xù)閱讀]

    Vegetable substances have been used for tanning since ancient times. The properties of vegetable-tanned leather include low extensibility,good strength,shape retention,storage of moisture,embossing properties,and polishing properties of the grain and of t...[繼續(xù)閱讀]

    Unhairing and liming may be carried out either separately,or at the same time by immersing the hides and skins completely in lime and sulfide liquor.3.1 Liming SystemStraight lime liquors of 2 parts lime per 100 parts water are chiefly used for skins that...[繼續(xù)閱讀]

    The term “finishing” refers to the further processing of the leather after drying. The aim is to adapt the leather to the fashion demands of the consumer with regard to color,surface effect,etc. by coating it with mixture of pigment,film forming material,...[繼續(xù)閱讀]

    Wet-blue is acid and develops acidity on standing. Under acid conditions the leather protein is cationic and this is further accentuated by the mineral retannage. Consequently negatively charged colloids,such as vegetable tans,amino-resins,dystuffs,fatliq...[繼續(xù)閱讀]