Patent Publication Number: US-4257816-A

Title: Novel blend of algin, TKP, and guar gum

Description:
CROSS-REFERENCE 
     CWSTG is taught and claimed in copending application U.S. Ser. No. 959,120, filed Nov. 9, 1978, entitled &#34;Cold-Water Soluble Tamarind Gum.&#34; Said application is incorporated herein by reference for its teaching of how to make CWSTG. 
     BACKGROUND OF THE INVENTION 
     Algin is a water-soluble polysaccharide found in all species of Phaeophyceae, brown algae. The generic term algin designates the derivatives of alginic acid chemically extracted from Phaeophyceae. The derivatives of alginic acid include varied soluble salts (e.g., sodium alginate) and salts of ethers (e.g., propylene glycol alginate); these derivatives, i.e., algin, are stored in their dry-powdered form. Algin is used in commercial gum applications for its thickening, suspending, emulsifying, stabilizing, adhesive, film-forming, and gel-forming properties. 
     Tamarind kernal powder is a commercially available product made by husking and milling the seed kernels of the tree Tamarindus indica Linn. 
     Guar gum is a commercially available product which is essentially the endosperm of the plant Cyanaposis tetragonolobus, family Leguminosae. Guar gum is used extensively as an additive in paper manufacturing as an aid in fiber-fiber bonding. Guar gum is also used as a flocculating agent in the mining industry since it flocculates clays, carbonates, hydroxides and silica. 
     SUMMARY OF THE INVENTION 
     It has now been found that a novel blend of algin, TKP (defined below), and guar gum can be used in a size press solution or in a pigmented paper coating formulation. Surprisingly, there is no evidence of flocculation in such a formulation even when clay is used as the pigment. 
     The ratio of algin:(TKP plus guar gum) on a weight:weight basis can range in said novel blend from about 90:10 to about 5:95. 
     The amounts of each gum in said novel blend can range, based on weight, as follows: 
     
         ______________________________________                                    
       algin        5%-90%                                                
       TKP          5%-90%                                                
       guar gum     5%-90%                                                
______________________________________                                    
 
    
     The novel blend of this invention develops very good viscosity and exhibits film-forming, ink holdout, and water retention properties (recognized parameters in the paper industry). It also exhibits good tensile strength and elongation of properties of films (recognized parameters for warp sizing used in the textile industry). Blends low in algin are preferred; i.e., algin:(TKP+guar gum)&lt;50:50. Most preferred are blends in the range 20:80 to 5:95. A most preferred blend is 20:50:30, algin:TKP:guar gum. Insofar as the gums themselves are concerned, high viscosity sodium alginate and cold-water soluble tamarind gum are preferred. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As used herein, algin is a generic designation for alginic acid and derivatives of alginic acid, including soluble salts (specifically sodium alginates) and soluble salts of its ethers (specifically propylene glycol alginates). 
     As used herein, TKP refers to (1) tamarind kernel powder, a commercially available product obtained from the seed kernels of the tree Tamarindus indica Linn; (2) cold-water soluble tamarind kernal powder (CWSTG) prepared by mixing crude tamarind kernal powder in water at a concentration of 0.1 to 75.0% (preferably 20-50%), heating the solution to a temperature of 35°-130° C. (preferably 70°-100° C.) until a paste is formed, then drying and milling the resulting product, which is cold water soluble tamarind kernal powder; (3) purified tamarind kernel powder as taught by U.S. Pat. No. 3,399,189 for obtaining the tamarind polysaccharide extract and by U.S. Pat. No. 3,287,350 for extraction of the tamarind polysaccharide as tamarind seed jellose (TSJ); and (4) other tamarind kernel powder constituents, i.e., the residual after the tamarind polysaccharide has been removed, viz, a combination of proteins, fiber, fat, inorganic salts, free sugars, and tannins. 
     Algin, TKP and guar gum can be blended to any desired ratio and stored as a blend until needed. These three components may be combined, each as a dry powder and stored as a dry-powder blend, or they initially may be put separately into solution and then the three solutions blended and stored as a wet blend or the separate solutions may be combined in the final formulation. The dry blends can be weighed and combined with other ingredients or first dissolved prior to further use. As tamarind kernel powder is not soluble in cold water, its entry into solution requires heating to approximately 82° C. Agitation by a mixer may also be required to put algin and TKP into solution. Guar gum is readily soluble in cold water although some grades may require up to 24 hours to develop maximum viscosity. In the wet blend, solutions in the range preferably of 0.5% to 10.0% of each component are prepared and then added together to attain the desired blend ratio. Final concentrations of the blend ranging from approximately 0.5% to 10.0% then can be prepared depending on the intended end use (for example, concentrations of 0.9% to 4.0% are typical of blends in the paper industry). Solutions lower than 0.5% and higher than 10% may also be prepared. 
     Blends of algin, TKP, and guar yield high viscosities in aqueous solutions when compared to the predicted viscosities resulting from addition of the individual viscosities of the three components blended in solution. 
     The blends of algin, TKP, and guar gum have utility as additives for: thickening, suspending, emulsifying, stabilizing, gelling, lubricating, film-forming, and binding. In particular, the blends can be used in the following applications or products: textile printing, can sealing, boiler compounds, latex creaming, welding-rod fluxes, brazing pastes, ceramic glazes and extrusions, cleaners and polishes, toys, emulsions (latex, asphalt, silicone), silver recovery, seed coatings, spray control for pesticides, emulsifiable concentrated and flowable pesticides, tobacco binders, water-based inks, lithographic fountain solutions, leather finishes, hydromulching and hydroseeding, textile printing and finishing, wet-end paper additives, wet-end paper retention and formation aids, anti-stick compounds, mold-release agents, liquid resins, slurry and packaged explosives, petroleum and water-well drilling muds, petroleum stimulation fluids, cosmetics, pharmaceutical suspensions and emulsions. This list is suggestive of the possible types of application in which these blends can be used. 
     The blends of algin, TKP, and guar gum are particularly useful in formulations used for paper coating and surface sizing. 
     Table I presents various application of the novel blend of this invention in the printing and paper industry. Percentages of the blend recommended for usage in a wide variety of coatings is shown for both pigmented and non-pigmented coating. 
     
                                           TABLE I                                 
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           Major Ingredient                                               
                     % Blend.sup.1                                        
                              % Total Solid                               
           (Parts by Weight)                                              
                     Useful   Useful                                      
Coating    Pigment.sup.2                                                  
                Binder.sup.3                                              
                     Range                                                
                         Preferred                                        
                              Range                                       
                                  Preferred                               
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Non-Pigmented                                                             
1. Calender Box                                                           
             --.sup.4                                                     
                 0-100                                                    
                     0.01-25                                              
                         0.01-10                                          
                              0.05-30                                     
                                  0.2-15                                  
2. Size Press                                                             
           --    0-100                                                    
                     0.01-35                                              
                         0.01-15                                          
                              0.1-30                                      
                                   5-15                                   
3. Blade Coater                                                           
           --    0-100                                                    
                     0.01-60                                              
                         0.01-25                                          
                              0.1-25                                      
                                   5-25                                   
Pigmented                                                                 
1. Wet-end Coater                                                         
           100  10-100                                                    
                     0.1-200                                              
                         0.2-100                                          
                               5-50                                       
                                  35-45                                   
2. Size Press                                                             
 Coater    100  3-30 0.1-200                                              
                         0.1-3.0                                          
                               5-60                                       
                                  25-50                                   
3. Calender Box                                                           
           100  3-30 0.1-200                                              
                         0.1-3.0                                          
                               5-60                                       
                                  25-50                                   
4. Roll Coater                                                            
           100  3-30 0.01-35                                              
                         0.05-1.5                                         
                              20-72                                       
                                  50-62                                   
5. Air Knife                                                              
 Coater    100  3-30 0.01-35                                              
                         0.05-1.5                                         
                              30-67                                       
                                  38-60                                   
6. Blade Coater                                                           
           100  3-30 0.01-35                                              
                         0.05-1.5                                         
                               2-72                                       
                                  30-68                                   
7. Rod Coater                                                             
           100  3-30 0.01-35                                              
                         0.05-1.5                                         
                              30-72                                       
                                  55-65                                   
8. Cast Coater                                                            
           100  8-30 0.01-35                                              
                         0.05-1.5                                         
                              35-70                                       
                                  40-62                                   
9. Gravure Coater                                                         
           100  3-30 0.01-35                                              
                         0.05-1.5                                         
                              35-72                                       
                                  40-64                                   
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 .sup.1 Values for nonpigmented coating are based on the total weight of  
 coating; for pigmented coatings on the amount of pigment.                
 .sup.2 Pigments include clay, TiO.sub.2, CaCO.sub.3, satin white, talc,  
 etc.                                                                     
 .sup.3 Binders include latex, casein, soya protein, starch, HEC, CMC,    
 animal glue, etc.                                                        
 .sup.4 Minute amounts of pigment are often used for the purpose of fillin
 the paper.                                                               
 
    
     In the examples, reference is made to the following tests, all of which are recognized in the paper industry. Parenthetical references are to standards of the Technical Association of the Pulp and Paper Industry, Inc., 1 Dunwoody Park, Atlanta, Ga., 30338. 
     1. K &amp; N® Mottle Test: the ink holdout property of a coating, i.e., estimates of resistance of a sheet of paper or paperboard to the penetration of ink and varnish are obtained by this method. A drop of K &amp; N gray oil-based ink is allowed to remain on a sample of treated paper and then the excess is wiped off. Poor ink film leveling gives a mottled appearance to the paper, which is rated on a scale of 0 to 10 (poor to good). (TAPPI 553) 
    
     2. IGT Ink Drop Test: this test measures pick resistance of paper by close simulation of the printing process. It simulates the ink holdout of a paper surface subjected to printing press nip pressure conditions (i.e., pick resistance of the paper). The spread size (in mm 2 ) of 0.3 ml of dibutylphtalate is measured on an IGT printability tester (Research Institute for Printing &amp; Allied Industries TNO, P.O. Box 4150, Amsterdam, Holland) at B setting, 40 kg nip pressure. Larger spread size indicates better ink holdout, which is desirable for gravure, litho, and letter-press applications. (TAPPI T499 su-64). 
     3. IGT Pick Test: this test measures the coated surface strength when it is printed with a specific tack-grade ink or Polybutene on an IGT tester. A higher reading means better coating strength. (TAPPI T-499). 
     4. Quick Peek Varnish Gloss: The test involves printing 0.02 mm 3  volume of gloss varnish distributed on 15,958 mm 2  area to the sample surface. After the varnish is dried, the measurement is made on the reflection gloss (TAPPI T-480). 
    
    
     The invention is further described in the following examples which should not be construed as limiting. 
     EXAMPLE 1 
     20:50:30 Gum Blend 
     A blend of 20:50:30 high viscosity sodium alginate (KELGIN® HV):cold-water soluble tamarind gum:guar gum (General Mills Chemical, Inc.) is prepared by dry mixing the indredients and then dissolving the mix in deionized water. 
     Using this blend, a pigmented coating formulation is prepared having the following composition: 
     
         ______________________________________                                    
                        Parts                                             
______________________________________                                    
Clay HT, No. 1 coating grade                                              
                          100                                             
Calgon®, tetrasodium pyrophosphate                                    
                          0.2                                             
Dispex® N40, organic dispersant                                       
                          0.2                                             
Dow 638 Latex®, latex binder                                          
                          15                                              
Gum blend                 0.4                                             
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     The pH is adjusted to 9±0.2 with ammonia. 
     A control formulation is prepared as above, omitting the use of the gum blend. 
     The viscosity data of Table II are obtained. 
     
                       TABLE II                                                    
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20:50:30 Gum Blend Viscosities                                            
            Brookfield LVF Model                                          
            Viscosity (cP)                                                
                          % Coating                                       
            6 rpm   60 rpm     Solid                                      
______________________________________                                    
w/gum blend   2100      360       45                                      
              4400      660       50                                      
              15000     2750      60                                      
w/o gum blend 25        15        45                                      
              100       30        50                                      
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     Viscosities are determined on a Brookfield LVF viscometer. Readings for 45% and 50% solids are taken at about 25° C.; 60% solids about 38° C. 
     EXAMPLE 2 
     Pigmented Paper Coating Test 
     Pigmented paper coatings, prepared as in Example 1 with and without the gum blend of this invention, are applied to paper. 
     The test results of Table III are obtained. Readings for 45% and 50% solids are taken at about 25° C.; 60% solids about 38° C. 
     
                       TABLE III                                                   
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Pigmented Paper Coating Test                                              
                 Dry                                                      
          %      Coat Wt. K &amp; N Ink                                       
                                  Quick IGT Pick                          
Coating   Solid  (gm/m.sup.2)                                             
                          Mottle  Peek  Test                              
______________________________________                                    
w/o gum blend                                                             
          45     15.0     3       44    44.41                             
          45     22.6     4       44    47.51                             
          50     14.7     4       43    41.41                             
          50     20.7     5       55    47.49                             
          60     18.2     6       50    47.50                             
          60     25.2     7       66    55.53                             
w/gum blend                                                               
          45     11.8     4       41    45.44                             
          45     18.9     5       52    50.50                             
          50     17.5     5       42    44.50                             
          50     21.3     6       55    57.55                             
          60     19.3     5       56    51.57                             
          60     27.7     6       60    59.62                             
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     These results indicate that there is no deterioration in the properties of the pigmented coating as a result of using the novel gum blend of this invention; i.e., surprisingly the guar gum containing blend has increased the viscosity of the pigment without flocculating with the clay. 
     EXAMPLE 3 
     Effect of Variation in Guar Content on Non-Pigmented Formulations 
     Five blends of this invention are prepared by combining a high viscosity sodium alginate (Kelgin® HV), cold-water soluble tamarind gum, and guar gum. 
     The gum ratios are: 
     
         ______________________________________                                    
       Sample                                                             
______________________________________                                    
       3-1           20:72:8                                              
       3-2           20:64:16                                             
       3-3           20:56:24                                             
       3-4           20:48:32                                             
       3-5           20:40:40                                             
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     These blends are then coated onto paper at 1% and 2% solids levels and the data of Table IV are obtained. 
     
                       TABLE IV                                                    
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Variation In Guar Level                                                   
            Brookfield LVF Model                                          
                          K &amp; N                                           
%           Viscosity (cP)                                                
                          Ink      IGT Ink                                
Sample Solid    6 rpm    60 rpm Mottle Drop                               
______________________________________                                    
3-1    1        250      190    5      565                                
3-1    2        3000     1800   6      659                                
3-2    1        400      280    4      504                                
3-2    2        5500     2700   6      702                                
3-3    1        500      320    4      566                                
3-3    2        8500     3425   6      613                                
3-4    1        600      420    4.5    497                                
3-4    2        13000    4600   7      612                                
3-5    1        1000     640    6      577                                
3-5    2        15750    4975   8      676                                
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     These data show that by increasing the percent of guar gum in the blends of this invention, there are obtained blends of increasing viscosity. These blends retain their utility as paper sizings. 
     EXAMPLE 4 
     Preparation of Cold-Water Soluble Tamarind Gum (CWSTG) 
     Tamarind kernel powder is dispersed in water to a concentration of 20%, heated to 95° C. for 10 minutes, then dried and milled. The resulting product is dissolved in water at 20° C. and develops a viscosity of 35 cP at 1% concentration, measured at room temperature on a Brookfield LVF viscometer, spindle 1, 60 rpm. 
     EXAMPLE 5 
     Preparation of Cold-Water Soluble Tamarind Gum (CWSTG) 
     Tamarind kernel powder is dispersed in water at ambient temperature at a concentration of 40%. The resulting paste is drum dried with internal steam pressure at 40 psi, and then milled. The resulting product readily dissolves in ambient-temperature water and imparts a viscosity of 30 cP at 1% concentration, measured on a Brookfield LVF viscometer, spindle 1, 60 rpm at room temperature. 
     EXAMPLE 6 
     Comparison of 20:50:30 Gum Blend vs. Guar Gum Alone 
     In order to compare the flocculating properties of the gum blend of this invention to guar gum, two pigmented coatings are prepared; one coating uses the 20:50:30 blend, the other uses guar gum alone. The coatings having the same formula as used in Example 1; the final solids are 60%. Interestingly, analytical tools such as viscosity readings (Brookfield, F-Shirley Rheogram, and Hercules Hi-shear Rheogram) do not distinguish significant differences between these two coatings as shown in Table V. However, the flocculation of the coating wherein guar gum alone is used is easily detected by spreading the coating on a glass plate. As it dries this coating achieves a mottled or cottage cheese-like appearance whereas the coating made from the gum blend of this invention dries smooth. 
     
                       TABLE V                                                     
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20:50:30 Blend vs. Guar Gum                                               
       Brookfield LVF                                                     
                    (cP)*    6/60 RPM                                     
                                     Hercules                             
Gum    6 RPM        60 RPM   Ratio   Hi-shear                             
______________________________________                                    
20:50:30                                                                  
       14,000       2300     6.1     20.5                                 
Blend                                                                     
Guar   17,500       3300     5.3     26.7                                 
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 *25°  C.