Patent Publication Number: US-4224169-A

Title: Flame retardant compositions and method of preparing same

Description:
BACKGROUND OF THE INVENTION 
     1. Field Of The Invention 
     The present invention relates to both aqueous-based and organic-based compositions for use in imparting flame retardant properties to a variety of materials including cellulosic materials, such as paper, cotton fabrics and wood, and also to polymeric materials, such as fabrics and films made from synthetic polymers. 
     2. Description Of The Prior Art 
     It is well known in the art that the flame retardant properties of flammable materials can be improved by coating the materials with flame retardant agents or by incorporating into the article itself a flame retardant substance. Literally thousands of flame retardant compositions and agents have been described in the literature, but in view of the importance of this technology, compositions offering improvements in properties continue to be investigated. 
     In particular, attention has been directed to producing flame retardant compositions which increase the resistance of an article to combustion upon the direct application of flame and at the same time do not deleteriously affect other desired properties of the article, such as strength, physical appearance and handling, absorption and like properties. 
     Applicant has now developed a series of compositions capable of improving the flame retardancy of articles made from both natural and synthetic materials without serious deterioration in properties of the articles and, in some cases, with increase in certain important properties. 
     An object of the invention, therefore, is to provide compositions capable of imparting improved flame retardancy to a variety of articles. 
     A second object of the invention is to provide compositions for improving fire and flame retardancy of articles while at the same time not adversely effecting the desirable properties of the articles to any substantial degree. 
     A further object of the invention is to provide compositions for improving the resistance of articles to combustion upon the direct application of flame. Other objects of the invention also include the provision of methods for preparing flame retardant compositions having the above-mentioned advantages. 
     SUMMARY OF THE INVENTION 
     The invention generally comprises the provision of both aqueous-based and organic-based flame retardant compositions useful in the coating of a variety of substrates and/or in the direct incorporation into manufactured articles so as to improve the flame retardancy of the articles without substantially diminishing the original properties and characteristics of the articles. 
     As to all of the flame retardant compositions within the scope of the present invention which will be described below, it is important to note that their toxicity index is negligible and that their odor is not unpleasant. These characteristics are important since the products treated with the instant compositions are products which are likely to be utilized in the household, places of public accommodation, vehicles, and the like where non-toxicity towards humans and favorable esthetic characteristics are highly desirable. 
    
    
     I. Aqueous-Based Composition Especially Adapted For Application To Cellulosic Articles 
     In accordance with the present invention, applicant has developed the following compositions particularly suited to the improvements of flame resistance in articles made in whole or in part from cellulosic substances, such as wood, paper, cotton and the like. 
     The preferred formulations are as follows: 
     
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COM-                                                                      
POUND                                                                     
No.   INGREDIENT          AMOUNT                                          
______________________________________                                    
1     Thiethanolamine Lauryl Sulphate                                     
                          0.5-6.0% by volume                              
                          (5-6 ml/l)                                      
2     Ammonium Iodide     2.0-7.0 parts by                                
                          weight (PBW)                                    
3     Ammonium Monophosphate                                              
                          1.5-8.0 PBW                                     
4     Ammonium Bromide    2.0-12.0 PBW                                    
5     Borax or Sodium Tetraborate                                         
                          1.5-20.0 PBW                                    
6     Boric Acid          1.5-7.0 PBW                                     
7     Ammonium Sulphate   3.5-20.0 PBW                                    
8     Sodium Silicate     0.1-1.0% by volume                              
                          (1-10 ml/l)                                     
9     1,2 Propylene Glycol                                                
                          1.5-10.0% by volume                             
                          (15-100 ml/l)                                   
 10   Water               to make one liter                               
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     Certain ingredients may also be added optionally to impart bactericidal and fungicidal properties to the compositions. By way of example, such additives may include acromicine, undecilenic acid and zinc undecilinate. 
     A particularly preferred composition within the scope of the above formulation is as follows: 
     
         ______________________________________                                    
COMPOUND                                                                  
NO.       INGREDIENT        AMOUNT                                        
______________________________________                                    
1         Triethanolamine   2.0% by volume                                
          Lauryl Sulphate                                                 
2         Ammonium Iodide   3.5 PBW                                       
3         Ammonium Monophosphate                                          
                            7.0 PBW                                       
4         Ammonium Bromide  3.0 PBW                                       
5         Borax             2.0 PBW                                       
6         Boric Acid        4.0 PBW                                       
7         Ammonium Sulphate 12.0 PBW                                      
8         Propylene Glycol  3.3% by volume                                
9         Sodium Silicate   0.5% by volume                                
10        Acromicine        2.0 PBW                                       
11        Undecilenic Acid  1.0 PBW                                       
12        Zinc Undecilinate 0.5 PBW                                       
13        Water             120.0 PBW                                     
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     In preparing the compositions as described above, it has been found to be important to follow a particular procedure. The following method should be employed: 
     Step 1 
     Referring to the particularly preferred composition, compounds 2, 3, 4, 5, 6 and 7 are mixed together to form a homogeneous mixture. 
     Step 2 
     Compounds 8, 10, 11 and 12 are mixed together to form a homogeneous mixture. 
     Step 3 
     To the product of Step 1, a portion of the water sufficient to dissolve the compounds, e.g., 50% of the total water, is added and the composition is heated to 70° C. with agitation continuously until the solids are dissolved. It is important to mention that the dissolution temperature of these ingredients should not exceed about 70° C. in order to avoid the loss of molecular water in the boric acid which could yeild metaboric or tetraboric acid, depending upon the temperature. Maintenance of the temperature below 70° C. is also important to prevent the boric acid from crystallizing. 
     Step 4 
     To one liter of the product of Step 3, there are added the compounds 9 and 1 plus the balance of the water. At this stage, the mixture of compounds 10, 11 and 12 from Step 2 is also added. 
     In utilizing the foregoing compositions, they may be applied in any conventional fashion to the surface of materials for the purpose of improving the flame retardancy of such materials. As earlier noted, the foregoing compositions are particuarly suited to production of cellulosic articles of improved flame retardancy. Coating might be done by immersion of the article, spraying, painting, roller coating or otherwise surface coating the article. It is also possible that the composition might be incorporated into the article, such as paper, by being added at one of the final stages of paper production, certainly at a stage beyond the point at which the composition might be washed-out or diluted. 
     When applied to paper and textiles, the foregoing composition surpasses the standards of the A.S.T.M. and N.F.P.A. with respect to combustion testing. 
     Besides improving fire retardancy, the particularly preferred compositions which incorporate the antibacterial and anti-fungal agent also have been found to increase the physical properties of cellulosic materials to which they are applied. 
     After treatment, substrate materials subjected to standard laboratory tests showed the following properties. 
     Sample 1 
     A 5 g piece of paper was treated with 20%, by weight, of this product on a dry basis. The original paper characteristics were affected as follows: 
     1. Strength 
     a. Tensile strength--increased by 20%. 
     b. Loosen strength--increased by 10%. 
     c. Weathering normal oxidation not affected. 
     d. Absorption--unchanged. 
     2. Physical Appearance 
     Opacity--increased by 0.20%. 
     3. Permeability 
     Permeability--affected by 5%. 
     4. Color 
     Color--change detectable only with spectrographic methods and increases by 0.2%. 
     5. Utilities 
     a. Printability--settled inks better by 20%. 
     b. Adhesive applications--increased adherence by 10%. 
     6. Chemical Resistance 
     Reaction to acids, alkalis and solvents is not increased or decreased after treatment. 
     7. Direct Flame Application 
     The treated paper is fire retardant. When direct flame is applied, the paper carbonizes where the flame is in direct contact, but there is no proliferation of the flame; when the flame is suspended, the flame disappears and the heat immediately is dissipated. 
     8. Indirect Heat Application 
     Paper carbonizes in an oven at 541.2° F. without flame. 
     Sample 2 
     A fabric swatch of cotton fiber containing a maximum of 40% synthetic fibers was treated with 20-30%, by weight, on a dry basis, of the fire retardant composition. The original characteristics of the fabric were affected as follows: 
     1. Strength 
     a. Tensile strength--increased by 30%. 
     b. Abrasion strength--increased by 10%. 
     c. Durability--increased from 5-15%. 
     d. Weathering--not affected under the same conditions as the untreated fabric. 
     2. Physical Characteristics 
     a. Roughness--slightly increased. 
     b. Brightness--not changed. 
     3. Permeability And/Or Absorption 
     No important changes. 
     4. Reaction To Colorants 
     Not affected in appearance, but colorants settled by 15%. 
     5. Utilities 
     a. Printability--cloth printings are not altered. Detergent action on the printed cloth does not affect the fiber or its appearance. 
     b. Abrasion resistance--increased by 20%. 
     c. Heat resistance--increased by from 5 to 15%. 
     6. Chemical Resistance 
     Influence of acids, alkalis and solvents is substantially unaffected by treatment. 
     7. Direct Flame Application 
     The fabric carbonizes with no proliferation of the flame; when the flame is suspended, the flame disappears as does the heat. 
     8. Indirect Heat Application 
     Fabric carbonizes at 541.2° F. without flame. 
     II. Composition For Application To Cellulosic Or Plastic Articles 
     The compositions of the present invention for use in imparting flame retardancy to articles made of a combination of cellulosic and plastic materials are capable of increasing flame resistance to a degree higher than any of the individual ingredients of the formulation are capable of doing. The compositions described below are preferably applied to fabrics made up of blends of cellulosic and synthetic fibers and particularly blends which include approximately 50% cotton and 50% synthetic fibers. 
     The formulations are prepared by producing a homogeneous mixture of the individual ingredients or components and then adding water at the final stage of the mixing. 
     The preferred compositions of this type have the following formulations: 
     
         ______________________________________                                    
INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Chlorinated Paraffin Hydrocarbons                                         
                      1.0-8.0%                                            
(Any chlorinated hydrocarbon                                              
having approximately 42%, by                                              
weight, of chlorine can be used,                                          
e.g., CLORAFIN 22)                                                        
Diisopropyl Ketone    0.5-5.0%                                            
Methyl Chloroform     0.5-5.0%                                            
Sodium Tungstate      0.5-5.0%                                            
Sodium Metaborate     0.5-5.0%                                            
Sodium Lauryl Sulphate                                                    
                      0.5-15.0%                                           
Hydroxy Propyl Methyl Cellulose                                           
                      5.0-15.0%                                           
Tripropylene Glycol   1.0-8.0%                                            
Fatty Alcohol         1.0-8.0%                                            
(Any primary alcohol with C.sub.8 --C.sub.11                              
carbon chain, generally linear,                                           
may be used)                                                              
Ortho Phenyl Phenol   0.1-2.0%                                            
Phenyl Mercuric Acetate                                                   
                      0.2-2.0%                                            
Ammonium Diphosphate  1.0-8.0%                                            
Ammonium Lauryl Sulphate                                                  
                      1.0-8.0%                                            
(This ingredient can be replaced                                          
by ammonium iodide used in the                                            
same proportion)                                                          
Water                                                                     
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     As the result of laboratory experiments in the application of such compositions to fabrics and other articles made from a combination or blend of cellulosic and synthetic polymeric materials, it appears that a particularly preferred formulation has the following composition: 
     
         ______________________________________                                    
INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Chlorinated Parraffin Hydrocarbon                                         
                      5.0%                                                
Diisopropyl Ketone    2.5%                                                
Methyl Chloroform     2.5%                                                
Sodium Tungstate      2.0%                                                
Sodium Metaborate     5.0%                                                
Sodium Lauryl Sulphate                                                    
                      10.0%                                               
Hydroxypropyl Methyl Cellulose                                            
                      10.0%                                               
Tripropylene Glycol   5.0%                                                
Fatty Alcohol         2.0%                                                
Ortho Phenyl Phenol   2.0%                                                
Phenyl Mercuric Acetate                                                   
                      0.2%                                                
Ammonium Diphosphate  5.0%                                                
Ammonium Lauryl Sulphate/                                                 
                      5.0%                                                
Ammonium Iodide                                                           
Water                 43.8%                                               
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     In one typical application of the above compositions, the material may be applied to a rug as a shampoo without dilution. In an application to fabrics such as upholstering fabrics, cloth or garments, drapes, etc., the above formulation is preferably diluted with about 50%, by volume, of water. All mixing and diluting operations are preferably performed at room temperature. 
     III. Composition For Use As Flame Retardant Paint Or Enamel 
     This composition provides an aqueous-based material useful as a flame retardant coating which may be applied in the same manner as conventional paints and enamels. 
     The composition is prepared by homogeneously mixing the individual components with water. The compositions of the present type have the following formulation: 
     
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INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Emulsion Of Acrylic Polymer                                               
                      from 23 to 28%                                      
Water                 43.8-53.6%                                          
Hydroxy Propyl Methyl Cellulose                                           
                      1.2-1.4%                                            
Tripropylene Glycol   0.8-1.0%                                            
Fatty Acid Alkanolamide                                                   
                      0.9-1.1%                                            
Ethyloxylated Ketosteracrylic                                             
                      0.9-1.1%                                            
Alcohol                                                                   
Phenyl Mercuric Acetate                                                   
                      0.18-0.24%                                          
Chlorinated Paraffin Hydrocarbon                                          
                      5.1-6.3%                                            
(Any chlorinated hydrocarbon can                                          
be used, such as CLORAFIN 22,                                             
which has approximately 42%, by                                           
weight, of chlorine)                                                      
Sodium Tungstate      2.0-2.4%                                            
Perchlorethylene      2.0-2.4%                                            
Barium Metaborate     0.9-1.1%                                            
Diisopropyl Ketone    1.9-2.3%                                            
Ammonium Phosphate    4.5-5.5%                                            
Ammonium Iodide       2.7-3.3%                                            
Silicic Acid (Hydrated Silica)                                            
                      0.27-0.33%                                          
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     As a result of laboratory experimentations with paints and enamels within the above formulations, it has been determined that the particularly preferred formulation is as follows: 
     
         ______________________________________                                    
INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Emulsion Of Acrylic Polymer                                               
                      25.5%                                               
Water                 48.7%                                               
Hydroxy Propyl Methyl Cellulose                                           
                      1.3%                                                
Tripropylene Glycol   0.9%                                                
Fatty Acid Alkanolamide                                                   
                      1.0%                                                
Ethyloxylated Ketosteracrylic                                             
                      1.0%                                                
Alcohol                                                                   
Phenyl Mercuric Acetate                                                   
                      0.2%                                                
Chlorinated Paraffin Hydrocarbon                                          
                      5.7%                                                
Sodium Tungstate      2.2%                                                
Perchlorethylene      2.1%                                                
Barium Metaborate     1.0%                                                
Diisopropyl Ketone    2.1%                                                
Ammonium Phosphate    5.0%                                                
Ammonium Iodide       3.0%                                                
Silicic Acid          0.3%                                                
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     Laboratory tests of paints and enamels formed from the above formulations compared with conventional paints and enamels when applied to substrates, such as wood, show the following effects on the properties of the products: 
     1. Physical Appearance--Unchanged 
     2. Ease Of Application--Unchanged. 
     3. Adherence--Increased by 20%. 
     4. Plasticity--Unchanged. 
     5. Durability--Increased by 12%. 
     6. Resistance To Corrosion--Increased by 7%. 
     7. Resistance To Weathering--Increased by 20%. 
     8. Permeability--Increased from 3 to 7%. 
     9. In paint manufacturing processes, the compositions do not alter the paint color; however, when incorporated in a previously prepared paint product, the formulation darkens the color of the original paint slightly. 
     10. Fire Resistance 
     Especially when applied to cellulosic materials, the composition avoids fire proliferation upon direct application of flame. 
     IV. Composition For Application To Synthetic Polymeric Substrates 
     The following compositions are useful in providing polymeric articles having improved fire retardancy and anti-oxidation characteristics. The compositions may be utilized by coating them on or impregnating them into polymeric articles by any known process, such as immersion, spray coating, painting, blending, etc. Under certain conditions, the compositions may also be incorporated directly into polymeric articles by adding the compositions to the polymerization matrix and separating and recovering the polymerizate together with the fire retardant composition upon completion of polymerization. 
     The preferred compositions within the scope of the invention have the following formulations: 
     
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INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Polyvinyl Chloride, e.g., Geon 121                                        
                      30.0-50.0%                                          
Dioctyl Phthalate     18.0-26.0%                                          
Tricresyl Phosphate   10.0-15.0%                                          
Cadmium and/or Tribasic Lead Sulphate,                                    
                      1.0-3.0%                                            
e.g., Ferro Mx (3091)                                                     
Calcium Carbonate     6.0-7.0%                                            
Plasticizer, e.g., Cereclor 552 or 70                                     
                      11.0-14.0%                                          
Aluminum              3.0-4.0%                                            
Antimonium Trioxide   3.0-4.0%                                            
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     As a result of laboratory experimentation, the following composition within the scope of the above formulations has been found to be particularly preferred: 
     
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INGREDIENT            AMOUNT (% by wt.)                                   
______________________________________                                    
Polyvinyl Chloride, e.g., Geon 121                                        
                      38.0%                                               
Dioctylphthalate      22.2%                                               
Tricresylphosphate    12.7%                                               
Cadmium and/or Tribasic Lead Sulphate,                                    
                      1.3%                                                
e.g., Ferro Mx (3091)                                                     
Calcium Carbonate     6.3%                                                
Plasticier, e.g., Cereclor                                                
                      3.1%                                                
Aluminum (Powder)     3.1%                                                
Antimonium Trioxide   3.7%                                                
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     In the above formulation, the antimonium trioxide may be replaced in the same proportion by methyl chloroform or sodium tungstate.