Process and composition for obtaining a rubbery tissue

Abstract

The present invention refers to a process and a composition, containing latex, for the manufacturing of rubbery tissue sheets. The process of the present invention consists of the following steps: formulation of the composition, consecutive impregnation and smoking cycles; and maturation. Also, it is part of the scope of the present invention, a impregnation composition which is essentially an aqueous solution comprising latex, a sulfur source and a vulcanization accelerator. The rubbery tissue sheets obtained by the present invention can be submitted to the manufacturing of: suitcases, bags, purses, travelling bags, clothes, diaries, wallets, shoes and other objects usually made of leather.

1 . Process for obtaining a rubbery tissue comprising the following steps: 
 (a) fixation of the impregnable material in a support;    (b) treatment of the external surface of the impregnable material;    (c) formulation, pH adjustment, homogenization under heating and filtration of the impregnation composition;    (d) impregnation, using the impregnation composition, of the external surfaces of the impregnable material, assuring that the said material absorbs the said composition;    (e) smoking of the impregnable material;    (f) submitting the external surface of the material thereof to successive cycles of impregnation and smoking; and    (g) maturating the material thereof under temperature range of 50-100° C.    
     
     
         2 . Process for obtaining a rubbery tissue, according to  claim 1 , comprising the previous step of extraction and assessment of the natural latex from the determination of the flag; tree incision; and fixation of a collector recipient on the inferior part of the incision.  
     
     
         3 . Process for obtaining a rubbery tissue, according to  claim 2 , wherein the flag corresponds to a half or a third of the total perimeter of the rubber tree and the incision is made in a inclined manner, allowing the latex flow.  
     
     
         4 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising the step of latex stabilization by adding one or more stabilizing agents or mixtures thereof to the said latex.  
     
     
         5 . Process for obtaining a rubbery tissue, according to  claim 4 , wherein a stabilizing agent is selected from the group comprised by, 10-100 mL 10% potassium hydroxide for 1-16 of latex, preferably 40-60 mL of 10% potassium hydroxide for 6-10 of latex, or 10% of potassium hydroxide solution, in a amount of 12 g of solution per Kg of latex containing 30% of total solids  
     
     
         6 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising the step of treatment of the external surfaces of the impregnable material by scraping and brushing the said external surfaces.  
     
     
         7 . Process for obtaining a rubbery tissue, according to  claim 6 , wherein the impregnable material is made of 100% cotton.  
     
     
         8 . Process for obtaining a rubbery tissue, according to  claim 6 , wherein a support for the said treatment of external surfaces is a rectangular vertical grid of 1.2×0.8 m.  
     
     
         9 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising a step of pH adjustment to a 6-10 range, preferably 7-9, most preferably 8; and homogenization under heating without boiling, in a 30-80° C. range, preferably 40-70° C., most preferably 55-60° C.  
     
     
         10 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, in which the impregnation process comprises the longitudinal application of an impregnation composition from the top to the bottom of the external surface of said impregnable material which is fixed on the said support; and spreading homogeneously on the said impregnable material.  
     
     
         11 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising a first application of the impregnation composition by manually rubbing the said impregnation composition, in order to avoid the passage of the said composition to the internal surface of the said impregnable material.  
     
     
         12 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising the application of the impregnation composition by using a hose.  
     
     
         13 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising the application of the impregnation composition by using a hose with diameter of 0.00254-0.0762 m (0.1-3 in), preferably 0.00762-0.0254 m (0.3-1 in), most preferably 0.010-0.016 m (0.4-0.6 in).  
     
     
         14 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising a smoking step, wherein the external surface of the impregnable material is exposed to the dense fumes of a conic oven.  
     
     
         15 . Process for obtaining a rubbery tissue according to  claim 14 , wherein the external surfaces of the impregnable material on the smoking step are exposed during 1-10 minutes, preferably 2-7 minutes, most preferably 3-5 minutes.  
     
     
         16 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, wherein the impregnable material is slightly sloped during the impregnation and smoking steps.  
     
     
         17 . Process for obtaining a rubbery tissue, according to any one of the preceding claim, wherein the smoked material is pressed previously to the subsequent impregnation step.  
     
     
         18 . Process for obtaining a rubbery tissue, according to any one of the preceding claim, wherein the cycles of impregnation and smoking are repeated 1-20 times, preferably 4-15 times, most preferably 6-12 times.  
     
     
         19 . Process for obtaining a rubbery tissue, according any one of the preceding claims, comprising a maturation step wherein the impregnated and smoked material is placed on a oven for 1-4 days, preferably 2-3 days at temperatures of 50-90° C., preferably 60-80° C., most preferably 70° C.  
     
     
         20 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, wherein at the beginning of the maturation step, a higher temperature is established, between 80-100° C., most preferably 90-95° C., followed by stabilization preferably at 70° C. during the maturation and curing steps.  
     
     
         21 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, comprising the additional steps of washing and drying of the impregnated, smoked and maturated material.  
     
     
         22 . Process for obtaining a rubbery tissue, according to any one of the preceding claims, wherein the resulting rubbery tissue sheets are coated with protection and/or anti-adherent agents.  
     
     
         23 . Impregnation composition, comprising an aqueous solution containing latex, sulfur source and a curing accelerator.  
     
     
         24 . Impregnation composition, according to  claim 23 , wherein the proportion between the sulfur source and the vulcanization accelerator is 1:1-1:3, most preferably 1:1.5.  
     
     
         25 . Impregnation composition, according to  claim 23 , comprising 4-12% sulfur; 2-8% zinc oxide; 6-21% vulcanization accelerator (preferably ZDEC-Akzo NL); 6-21% protecting and stabilizing agent (preferably Wingstay L-Goodyear EUA); 8-24% dispersing agent (preferably Faxan 11P at 10%-Montanoir F); 2-6% thickening agent (preferably AlGum HV at 3%-Mathon F); and 10-80% water (all percentages in weight), establishing a relationship among active chemicals and rubber amount of 1:0.5-1:2, preferably 1:1.  
     
     
         26 . Impregnation composition, according to  claim 25 , comprising a lower level of sulfur, around 0.6%, in order to avoid the blooming effect; a more active accelerator than the ZDBC and a protective material that avoids bleaching.