Manufacturing process of a paper substrate intended to be vulcanised or parchmentised

Abstract

A manufacturing process of a paper substrate intended to be vulcanised or parchmentised, consisting in: subjecting, in a dry state, the cellulose fibres to energy radiation; defiberizing and refining in an aqueous environment the irradiated fibres until a homogenous fibre solution is obtained; forming a web from the obtained fibre suspension, which is then drained and dried to obtain the actual paper substrate.

1 . A manufacturing process of a paper substrate intended to be vulcanised or parchmentised, comprising the steps of 
 subjecting, in a dry state, the cellulose fibres to energy radiation,    separating and refining in an aqueous environment the radiation-treated fibres until a homogenous fibre solution is obtained,    forming a web from the obtained fibre suspension, which is then drained and dried to obtain the actual paper substrate.    
     
     
         2 . A process according to  claim 1 , characterized in adding to the fibre suspension being exposed to energy radiation, cellulose fibres of the same origin, exposed to energy radiation or not, and/or cellulose fibres of different origin, exposed to energy radiation or not, and/or synthetic and/or mineral non-cellulose fibres.  
     
     
         3 . A process according to  claim 1 , characterized in that the fibre suspension contains at least 20%, advantageously at least 50% by weight of the cellulose fibres exposed to energy radiation.  
     
     
         4 . A process according to  claim 1 , characterized in that the cellulose fibres exposed to energy radiation are cotton fibres.  
     
     
         5 . A process according to  claim 4 , characterized in that the cotton fibres exposed to energy radiation are virgin cotton fibres coming from sheets or compressed pulp.  
     
     
         6 . A process according to  claim 5 , characterized in that the energy radiation is a radiation by electron beams or by x-radiation.  
     
     
         7 . A process according to  claim 4 , characterized in that the cotton fibres exposed to energy radiation come from textile industry waste.  
     
     
         8 . A process according to  claim 7 , characterized in that the cotton fibres come from jeans waste first cut, then sorted and shredded, the fibres being exposed to a radiation by electron beams either right after the cutting step, and prior to the shredding step, or right after the shredding step.  
     
     
         9 . A process according to  claim 7 , characterized in that the cotton fibres come from jeans waste in the form of bales containing the jeans manufacture rags, possibly cut and then shredded, the entire bale being exposed to X-radiation.  
     
     
         10 . A process according to  claim 4 , characterized in that, when the paper is intended to be vulcanised, the irradiation dose absorbed by the cotton fibres is between 10 and 30 kGy.  
     
     
         11 . A process according to  claim 4 , characterized in that, when the paper is intended to be vulcanised, the DP of the irradiated cotton fibres is between 350 and 500.  
     
     
         12 . A process according to  claim 4 , characterized in that, when the paper is intended to be parchmentised, the irradiation dose absorbed by the cotton fibres is between 5 and 20 kGy.  
     
     
         13 . A process according to  claim 4 , characterized in that, when the paper is intended to be parchmentised, the degree of polymerisation of the irradiated cotton fibres is less then 700.  
     
     
         14 . A manufacturing process of a paper intended to be vulcanised or parchmentised comprising the steps of: 
 separating and refining in an aqueous environment cellulose fibres contained in a mixture of fibres until a homogenous fibre suspension is obtained,    forming a web from the suspension, which is next drained and dried until the actual paper substrate has been obtained, and    lowering the degree of depolymerisation of the fibres by exposing the paper substrate to energy radiation.    
     
     
         15 . A process according to  claim 14 , characterized in that the mixture of fibres contains at least 20%, preferably at least 50% by weight, most preferably 100% by weight of the cellulose fibres.  
     
     
         16 . A process according to  claim 14 , characterized in that the cellulose fibres are exclusively virgin cotton fibres coming from sheets or compressed pulp.  
     
     
         17 . A process according to  claim 14 , characterized in that the cotton fibres, defiberized and then refined in an aqueous environment, come from textile waste.  
     
     
         18 . A process according to  claim 17 , characterized in that the textile waste comes from jeans industry.  
     
     
         19 . A process according to  claim 14 , characterized in that the fibre suspension contains 100% by weight of cotton fibres.  
     
     
         20 . A process according to  claim 14 , characterized in that the energy radiation is a radiation by electron beams.  
     
     
         21 . A process according to  claim 19 , characterized in that, when the paper is intended to be vulcanised, the radiation dose absorbed by the cotton fibres is between 10 and 50 kGy.  
     
     
         22 . A process according to  claim 19 , characterized in that, when the paper is intended to be vulcanised, the degree of polymerisation of the irradiated cotton fibres is less then 700, advantageously between 200 and 300.  
     
     
         23 . A process according to  claim 19 , characterized in that, when the paper is intended to be parchmentised, the degree of polymerisation of the irradiated cotton fibres making up the obtained paper sheet is between 400 and 600, advantageously 500.  
     
     
         24 . A process according to  claim 19 , characterized in that, when the paper is intended to be parchmentised, the irradiation dose absorbed by the cotton fibres is between 5 and 30 kGy.  
     
     
         25 . A process for vulcanizing a paper substrate comprising providing a paper substrate obtained by the process of  claim 1 , and subjecting the paper substrate to a vulcanizing operation.  
     
     
         26 . A process for parchmentising a paper substrate comprising providing a paper substrate obtained by the process of  claim 1 , and subjecting the paper substrate to a parchmentising operation.