Application Of Leather Waste In Papermaking Industry

The global warming climate indicates the importance of environmental protection. The industrial tanning of leather usually produces considerable amount of solid waste. The waste is partly utilized, but mainly it is deposited in storage yards, posing a hazard to the environment, resulting in a considerable loss of usable resource. It is importantly significant to treat leather solid waste for protecting environment. As an important and useful method, resource-orientation utilization of leather solid waste not only recyclessignificant resources, but also solves the problem of waste pollution.With papermaking technique, we develop a method of treating leather solid waste. The study focuses on fibre utilization and unfibre utilization.Adopting the way of Papermaking, we develop the technique of leather waste pre-treatment,the pulp&papermaking property of leather fibre concerning the fibrous utilization. We successfully prepare the high porosity,high strength fruit cultivating bag paper via compound with wood fibre. On the other hand we modify hydrolyzing protein with blending process concerning the unfibrous utilization.The pre-treatment results are as follows: the high strength and the well dispersive leather fibre can be prepared under the condition of sodium hydroxide 2%,liquid-solid ratio 1/5,cooking temperature 120°C,cooking time 20 min,refiner clearance 0.3 mm,. The effect of leather fibre ratio has been analyzed, and the result show that: with the ratio of 10% leather fibre, the formation of compound paper can be increased 41.48%, but the formation drops 6.99% after the ratio of leather fibre rises up to 30%.The result of beating experiment demonstrates that lower leather beating degree (34°SR) can improve the porosity of compound paper by 23.69%. It is the first time that we find that the leather fibre can be developed into reinforced fibre after beat with antifoam reagent. After adding 20% leather fiber, the tensile index and tear index of compound paper increase 17.99% and 14.93% respectively.The development of fruit cultivating bag paper shows that: the fruit cultivating bag paper prepared with technics of pH7, PAE1.5%, waterproof 2%, 35°SR leather pulp&wood pulp(softwood),20 % leather fibre can meet the National Standard. The idiographic parameter is dry strength 61.91N·m·g-1,wet strength 41.49 %, porosity 40.04μm·(Pa·S)^-1, tear index 10.12 mN·m²Â·g^-1, surface absorbability 11.58g·m^-2.The sample we develop can solve the problem of low porosity of domestically-made fruit bag paper.At the same time, we modify hydrolyze protein with PAE as strengthening agent .The study indicates that: the best blending process is PAE10%,temperature 40°C,pH6.5,the concentration of hydrolyze protein 17%,blending time 2h. The paper dry strength can increase 52.97% and wet strength reaches 21.84% when adding 4% blend solutions with2% Alu.Based on the SEM observation, beating can disentangle the Triple-Helix of leathe fibre, making the regular disc-like shape of leather fibre turn into ruleless,incompact fibre, furthermore unwinding the Triple-Helix on surface of leather fibre and producing more privitive fibre,fibril,filament,therefore enhancing the bonded area, which increases the strength of compound paper. IR analysis indicates that: beating increases hydrophile group of lether fibre, more Hydrogen Bond form between wood fibre and leather fibre. TG analysis show that: Fruit bag paper with leather fibre enjoy highthermal stability.The results indicate that: with the properly treated leather waste, reinforced fibre and strengthening agent can be prepared. This technic can be applied for papermaking industry, which becomes a novel approach for resource-orientation of leather solid waste.