Wet strength improved fibrous non-woven fabrics, in particular paper, uses of these wet strength fabrics as well as production methods of the same

Abstract

Novel environmentally friendly, wet strength improved fibrous non-woven fabrics, optionally paper, impregnated with a mixture including a silicon component, further including water and/or an alcohol and/or a surfactant and a catalyst. Also encompassed are methods for production and uses of such wet strength improved fibrous non-woven fabrics.

What is claimed is: 
     
         1 . A wet strength improved fibrous non-woven fabric with an air-dry silica-content of at least 0.1 wt.-%, wherein the silica is distributed in the wet strength fibrous non-woven fabric in so far that the silica-content on one side of the wet strength fibrous non-woven fabric and the silica-content on another side of the wet strength fibrous non-woven fabric is a ratio about 1:1, and wherein a Cobb 60 -value is less than 20% reduced as compared to the untreated fibrous non-woven fabric. 
     
     
         2 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein the fibrous non-woven fabric is selected from the group consisting of paper and cotton fleece. 
     
     
         3 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein a wet tensile strength according to DIN ISO 3781 of the fibrous non-woven fabric is between at least 5 times and up to 50 times higher than the wet tensile strength according to DIN ISO 3781 of a fibrous non-woven fabric without silica-content. 
     
     
         4 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein the wet tensile strength according to DIN ISO 3781 (1994-10) is between 1 and 50 N/15 mm. 
     
     
         5 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein the air-dry silica content is between at least 0.1 wt.-% and up to 30 wt.-%. 
     
     
         6 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein a contact angle on all surfaces of the wet strength improved fibrous non-woven fabric according to the present invention is less than 90°. 
     
     
         7 . The wet strength improved fibrous non-woven fabric according to  claim 1 , wherein the silica coated paper wet strength improved fibrous non-woven fabric has a water absorption capacity according to DIN EN ISO 535 (2014) is between 10 g/m 2  and 300 g/m 2 . 
     
     
         8 . The wet strength improved fibrous non-woven fabric according to  claim 1 , obtained by impregnating the fibrous non-woven fabric with a mixture comprising a silicon component, water, a surfactant and an acidic catalyst. 
     
     
         9 . A mixture comprising the following compounds in weight-%: 
       
         
           
                 
                 
               
                     
                 
                   Compound 
                   wt.-% 
                 
                     
                 
                   silicone compound (e.g., tetraethyl orthosilicate, (TEOS)) 
                   3.5-15  
                 
                   surfactant 
                   0.2-1.5 
                 
                   H 2 O 
                   80-95 
                 
                   acidic catalyst 
                    0.06-0.05. 
                 
                     
                 
             
                
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         10 . The mixture of  claim 9 , wherein the surfactant is a cationic surfactant. 
     
     
         11 . A mixture comprising the following compounds in weight-%: 
       
         
           
                 
                 
               
                     
                 
                   Compound 
                   wt.-% 
                 
                     
                 
                   silicone compound (e.g., tetraethyl orthosilicate, (TEOS)) 
                    2-20 
                 
                   H 2 O 
                    6-10 
                 
                   alcohol (e.g., EtOH) 
                   75-90 
                 
                   acidic catalyst 
                    0.01-0.05. 
                 
                     
                 
             
                
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         12 . The wet strength improved fibrous non-woven fabric according to  claim 1 , obtained by impregnating the fibrous non-woven fabric with a mixture comprising the following compounds in weight-%; 
       
         
           
                 
                 
               
                     
                 
                   Compound 
                   wt.-% 
                 
                     
                 
                   silicone compound (e.g., tetraethyl orthosilicate, (TEOS)) 
                   3.5-15  
                 
                   surfactant 
                   0.2-1.5 
                 
                   H 2 O 
                   80-95 
                 
                   acidic catalyst 
                    0.06-0.05. 
                 
                     
                 
             
                
                
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         13 . A method for producing a wet-strength improved fibrous non-woven fabric, optionally paper, comprising the steps of:
 a. obtaining a fibrous non-woven fabric;   b. applying an impregnation solution according to  claim 9  evenly to both sides of the paper with a size press with a speed of between 1 to 15 m/min at a roll pressure of between 0.25-3.0 bar;   c. heating the paper from between 18-25° C. to between 60-200° C. with a heating rate of between 5-15 K/min under constant air flow of between 15-50 mL/min;   d. thereby obtaining the wet-strength improved fibrous non-woven fabric, optionally paper.   
     
     
         14 . A method for producing a wet-strength improved fibrous non-woven fabric, optionally paper, comprising the steps of:
 a. mixing the impregnation solution according to  claim 9  in a bath with fibres for the fibrous non-woven fabric;   b. extracting the fibrous non-woven fabric from said bath;   c. heating the paper from between 18-25° C. to between 60-200° C. with a heating rate of between 5-15 K/min under constant air flow of between 15-50 mL/min;   d. thereby obtaining the wet-strength improved fibrous non-woven fabric, optionally paper.   
     
     
         15 . A method, comprising the steps of: 1) using the wet-strength improved fibrous non-woven fabric of any of  claim 1  or 2) using an impregnation solution comprising the following compounds in weight-%: 
       
         
           
                 
                 
               
                     
                 
                   Compound 
                   wt.-% 
                 
                     
                 
                   silicone compound (e.g., tetraethyl orthosilicate, (TEOS)) 
                   3.5-15  
                 
                   surfactant 
                   0.2-1.5 
                 
                   H 2 O 
                   80-95 
                 
                   acidic catalyst 
                   0.06-0.05 
                 
                     
                 
             
                
                
                
               
               
                
                
                
                
                
               
            
           
         
       
       on a fibrous non-woven fabric for producing an article with improved wet tensile strength selected from the group comprising tea bags, kitchen paper, cardboard, map paper, security paper for bank notes, coffee or tea filters, wrapping paper, toilet paper, paper towels, cooking paper, paper labels, display boards, promotional poster, drinking straws, packaging papers, corrugated boards, paper bags, and cloths. 
     
     
         16 . The wet strength improved fibrous non-woven fabric according to  claim 2 , wherein the wet tensile strength according to DIN ISO 3781 of the fibrous non-woven fabric is between at least 5 times and up to 50 times higher than the wet tensile strength according to DIN ISO 3781 of a fibrous non-woven fabric without silica-content, and wherein the wet tensile strength according to DIN ISO 3781 (1994-10) is between 1 and 50 N/15 mm. 
     
     
         17 . The wet strength improved fibrous non-woven fabric according to  claim 16 , wherein the air-dry silica content is between at least 0.1 wt.-% and up to 30 wt.-%, and wherein the contact angle on all surfaces of the wet strength improved fibrous non-woven fabric according to the present invention is less than 90°. 
     
     
         18 . The wet strength improved fibrous non-woven fabric according to  claim 17 , wherein the wet strength improved fibrous non-woven fabric has a water absorption capacity according to DIN EN ISO 535 (2014) is between 10 g/m 2  and 300 g/m 2 , and obtained by impregnating the fibrous non-woven fabric with a mixture comprising a silicon component, water, a surfactant and an acidic catalyst. 
     
     
         19 . The wet strength improved fibrous non-woven fabric according to  claim 18 , obtained by impregnating the fibrous non-woven fabric with a comprising the following compounds in weight-%: 
       
         
           
                 
                 
               
                     
                 
                   Compound 
                   wt.-% 
                 
                     
                 
                   silicone compound (e.g., tetraethyl orthosilicate, (TEOS)) 
                   3.5-15  
                 
                   surfactant 
                   0.2-1.5 
                 
                   H 2 O 
                   80-95 
                 
                   acidic catalyst 
                    0.06-0.05.