Study On Finishing Technology Of High-grade Cow Upper Shoes Leather

Leather industry is one of the industries with international competitiveness in China,and plays an important role in the national economy.At present,a general difficulty for tanneries is that the wet blue leathers with different grades have to be purchased as a bulk commodity together.Among these raw materials,grade C leather with a lot of natural disabilities,which belongs to the lowest grade,is accounting for about 55% of the raw materials in tanneries.The B-class leather,with a lot of natural small disabilities,is accounting for about 35% of blue leather in tanneries.The A-class leather,which has a small amount of natural small disabled on the surface,only accounts for about 10% of the raw leather in tannery.For shoe upper leather manufacturers,how to reasonably adjust the product structure,how to make different grades of raw materials to achieve the same quality grade of finished leather,and how to maximize the economic value of all grades of products has become an urgent problem.In view of the current situation of our enterprise,this paper puts forward a new idea of developing different kinds of shoe upper leather from different grades of cattle wet blue.Firstly,the production process of white reconditioned shoe upper leather used by C-grade leather was developed.The peel strength of the finished leather was increased from 16.37N/mm to 22.47 N/mm by using special materials such as high efficiency penetrant.The yellowing resistance of finished leather were more than or equal to 4.5 grade by using raw chemicals with high yellowing resistances.By optimizing the proportion and spraying amount of various materials in the coating,the bending resistance of finished leather at room temperature increased from 124,000 times to 154,000 times on average,and the bending resistance at low temperature increased from 64,000 times to 87,000 times on average.By using polycarbonate polyurethane varnish taking place of conventional polyurethane varnish,the average wear resistance of finished leather is increased from 60 turns to 86 turns.Then,the production process of light repair oil wax shoe upper leather with B-grade leather was developed.When the embossing parameters are temperature 110?,pressure120 kg and holding time 5 s,it can not only ensure the embossing stereotypes of the base slurry,but also maintain the softness of the leather.When the polishing parameters are1500 r/min,28 m/min and-0.8 mm,the finished light polish oil wax shoe upper leather has good grain fineness.Finally,the production process of full grain oil wax shoe upper leather by using Agrade wet blue was developed.After using full grain patching paste and oil wax with melting point lower than 90?,the grain fineness of finished leather was significantly improved.Using non-ionic back sealing system,the finished full grain oil wax shoe upper leather has excellent bottom gloss effect.When the vacuum parameters are 70? and the holding time is 70 s,the surface gloss of the finished leather is more durable.