Abstract:
The invention relates to a flame-retardant coating for fiber materials comprising at least one film-forming binder and one flame retardant, wherein this comprises melamine polyphosphate as flame retardant. 
     The invention also relates to the use of the novel flame-retardant coating for producing flame-retardant fiber materials.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a flame-retardant coating for fiber materials comprising at least one film-forming binder and one flame retardant, and to the use of a flame-retardant coating of this type. 
     Fiber materials, for example in the form of textile sheets, such as fabrics for drapes, carpeting, covers for automobile seats, railroad seats, or covers for children&#39;s beds, etc. composed of, for example, cotton, cellulose fibers, polyester fibers, polyethylene fibers, polyamide fibers, polypropylene fibers or fiber mixtures ignite readily in the event of a fire. 
     It is known that textiles can be treated with compositions of decabromodiphenyl ether and other flame retardants, such as antimony trioxide and alumina trihydrate in the form of aqueous dispersions, in order to render them flame-retardant. These coatings contain halogen and therefore are in many cases not usable, in particular for textiles with which children come into contact. 
     Many attempts have therefore been made to replace these halogen-containing products with halogen-free products. Examples of halogen-free products used hitherto to render textiles flame-retardant are the known ammonium and sodium salts of phosphoric acid. 
     Disadvantages of these products are that firstly they do not give a satisfactory flame-retardant effect on fiber materials, and secondly that their high water solubility means that they are very rapidly removed as a result of washing. 
     Compositions of this type based on ammonium polyphosphate have given a more favorable result in this context insofar as water solubility and the effectiveness of flame-retardant action is concerned, but these are still not completely satisfactory. For example, ammonium polyphosphate tends to become tacky (“froggy hand”) in the presence of moisture. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to provide a flame-retardant coating for fiber materials which avoids the disadvantages mentioned and is as good as previous compositions with respect to flame-retardant action and also “froggy hand” and superior to these in terms of freedom from halogen. 
     This object is achieved by a flame-retardant coating for fiber materials of the type described at the outset, wherein this comprises melamine polyphosphate as flame retardant. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The melamine polyphosphate preferably has the formula (HMPO 3 ) n , where M is melamine and n≧2, in particular from 2 to 10,000. 
     Melamine polyphosphate is a polymer composed of melamine units and phosphate units, linked to form chains of varying length. The distribution of the melamine units and phosphate units may be regular or irregular, and they may, if desired, also have been polymerized within themselves. Derivatives of melamine, such as melem, melam and others, may also be present. 
     The properties of the melamine polyphosphate may vary within certain limits due to variations in its chain length and in the distribution and/or frequency of the melamine units and phosphate units. 
     Melamine polyphosphate is described in more detail in PCT/WO 98/45364, for example, where it is also termed melamine salt of polyphosphoric acid. The polymeric chain here is composed of (HMPO 3 ) n  units [where M is melamine] and n≧2, in particular from 5 to 10,000. 
     Melamine polyphosphate is usually obtained by heating melamine pyrophosphate to constant weight under nitrogen at a temperature of 290° C. or above (PCT/WO 98/08898). 
     It is preferable for the film-forming binder to be 
     homopolymers based on vinyl acetate, 
     copolymers based on vinyl acetate, ethylene and vinyl chloride, 
     copolymers based on vinyl acetate and on the vinyl ester of a long-chain, branched carboxylic acid, copolymers based on vinyl acetate and di-n-butyl maleate, 
     copolymers based on vinyl acetate and acrylates, and/or 
     copolymers based on acrylates, 
     vinyltoluene-acrylate polymers, 
     styrene-acrylate polymers, 
     vinyl-acrylate copolymers, and/or 
     self-crosslinking polyurethane dispersions. 
     It is particularly preferable for the film-forming binder to be polyvinyl acetate copolymers or polyacrylates. 
     It is preferable for the ratio between the amount of film-forming binder (100% strength) and melamine polyphosphate to be from (10 to 1) to (1 to 5). 
     It is particularly preferable for the ratio between the amount of film-forming binder (100% strength) and melamine polyphosphate to be from (5 to 1) to (1 to 3). 
     It is preferable for water, and also, if desired, conventional auxiliaries and additives, to be present as further components. 
     It is preferable for the auxiliaries and additives present to comprise dispersing agents, foaming agents, foam stabilizers, thickeners, fungicides and/or antifoams. 
     It is preferable for the fiber materials to be fabrics for drapes, carpeting, covers for automobile seats or for railroad seats, or covers for children&#39;s beds, composed of cotton, cellulose fibers, polyester fibers, polyethylene fibers, polyamide fibers, polypropylene fibers and/or other fiber mixtures. 
     The novel flame-retardant coating is suitable for practically any conceivable fiber material, and its use is therefore not restricted to the abovementioned application sectors. 
     Finally, the invention also provides the use of the novel flame-retardant coating for producing flame-retardant fiber materials. 
     In each of the examples below, a flame-retardant coating is first produced, and a certain thickness of this is applied to the appropriate fiber materials and dried. Depending on the nature and composition of the flame-retardant coating and of the fiber material in the fabric the product may then, if desired, be foamed, dried or crosslinked. 
     The coatings were then tested to the following standards: 
     for fire protection regulations in buildings: 
     DIN 4102 Part 1 
     for automobiles: FMVSS 302 
     for railroads: DIN 54336. 
     The freedom from tack of the coatings applied was assessed visually after storage under appropriate temperature and humidity conditions. 
    
    
     The invention is illustrated by the examples below. 
     EXAMPLES 
     Example 1 (Comparison) 
     Reverse-side coating for automotive insulating material 
     
       
         
               
               
               
               
             
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Polyvinyl acetate dispersion 
                 600 
                 g/l 
               
               
                   
                 (50% strength) 
               
               
                   
                 Decabromodiphenyl ether 
                 80 
                 g/l 
               
               
                   
                 Antimony trioxide 
                 40 
                 g/l 
               
               
                   
                 Alumina trihydrate 
                 80 
                 g/l 
               
               
                   
                 Foaming agent 
                 5 
                 g/l 
               
               
                   
                 Application: 
               
               
                   
                 1. Foaming 
               
               
                   
                 2. Amount applied 
                 180 
                 μm 
               
               
                   
                 3. Drying 
                 at 150° 
                 C. 
               
               
                   
                 4. Coating weight 
                 100 
                 g/m 2   
               
             
          
           
               
                   
                 Flammability test: FMVSS 302 
               
               
                   
                 Result: SE 
               
               
                   
                 Moisture test (storage at 40° C. and 95% 
               
               
                   
                 humidity for 24 h): no tack 
               
               
                   
                   
               
             
          
         
       
     
     Example 2 (Comparison) 
     
       
         
               
               
               
               
             
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 PVA dispersion (50% strength) 
                 600 
                 g/l 
               
               
                   
                 Ammonium polyphosphate, 
                 120 
                 g/l 
               
               
                   
                 solubility &lt;0.1% 
               
               
                   
                 Melamine 
                 40 
                 g/l 
               
               
                   
                 Dipentaerythritol 
                 30 
                 g/l 
               
               
                   
                 Dispersing agent 
                 2 
                 g/l 
               
               
                   
                 Foaming agent 
                 5 
                 g/l 
               
               
                   
                 Application: 
               
               
                   
                 1. Foaming 
               
               
                   
                 2. Amount applied 
                 180 
                 μm 
               
               
                   
                 3. Drying 
                 at 150° 
                 C. 
               
               
                   
                 4. Coating weight 
                 100 
                 g/m 2   
               
             
          
           
               
                   
                 Flammability test: FMVSS 302 
               
               
                   
                 Result: SE 
               
               
                   
                 Moisture test (as in Example 1): slight tack, 
               
               
                   
                 disappearing on drying. 
               
               
                   
                   
               
             
          
         
       
     
     Example 3 
     
       
         
               
               
               
               
             
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 PVA dispersion (50% strength) 
                 600 
                 g/l 
               
               
                   
                 Melamine polyphosphate 
                 160 
                 g/l 
               
               
                   
                 Foaming agent 
                 5 
                 g/l 
               
               
                   
                 Application: 
               
               
                   
                 1. Foaming 
               
               
                   
                 2. Amount applied 
                 180 
                 μm 
               
               
                   
                 3. Drying 
                 at 150° 
                 C. 
               
               
                   
                 4. Coating weight 
                 100 
                 g/m 2   
               
             
          
           
               
                   
                 Flammability test: FMVSS 302 
               
               
                   
                 Result: SE 
               
               
                   
                 Moisture test (as in Example 1): absolutely tack-free 
               
               
                   
                   
               
             
          
         
       
     
     Example 4 
     
       
         
               
             
               
               
               
               
             
               
               
               
             
               
               
             
               
               
             
               
               
             
           
               
                   
               
               
                 Automotive and railroad seat covers 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Polyacrylate dispersion 
                 550 
                 g/l 
               
               
                   
                 (45% strength) 
               
               
                   
                 Water 
                 100 
                 g/l 
               
               
                   
                 Melamine resin 
                 30 
                 g/l 
               
               
                   
                 Melamine polyphosphate 
                 90 
                 g/l 
               
               
                   
                 Foaming agent 
                 3 
                 g/l 
               
               
                   
                 Foam stabilizer 
                 5 
                 g/l 
               
               
                   
                 Application: 
               
               
                   
                 1. Foaming 
               
             
          
           
               
                   
                 2. Amount applied 
                 30 g of flame retardant 
               
               
                   
                   
                 per 100 g of fabric 
               
               
                   
                 3. Drying 
                 at 170° C. 
               
             
          
           
               
                   
                 Flammability test: 
               
             
          
           
               
                 a) 
                 Railroad seats: test methods as in E-DIN 54837 
               
               
                   
                 Result: S 4, ST 2, SR 2 
               
               
                 b) 
                 Automobile seats: FMVSS 302 test methods 
               
               
                   
                 Result: SE 
               
             
          
           
               
                   
                 Moisture test: (as in Example 1 and after 48 
               
               
                   
                 and 96 h): absolutely tack-free 
               
               
                   
                   
               
             
          
         
       
     
     Example 5 
     
       
         
               
             
               
               
               
               
             
               
               
             
           
               
                   
               
               
                 Carpet-back coating 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 PVA copolymer dispersion 
                 100 
                 parts 
               
               
                   
                 (50% strength) 
               
               
                   
                 Melamine polyphosphate 
                 130 
                 parts 
               
               
                   
                 Water 
                 30 
                 parts 
               
               
                   
                 Application: 
               
               
                   
                 1. Amount applied 
                 300-400 
                 g/m 2   
               
               
                   
                 2. Drying 
                 at 130° 
                 C. 
               
             
          
           
               
                   
                 Flammability test: Test methods as in DIN 54336 
               
               
                   
                 Result: Vertical test, 3 sec. Flame application - 
               
               
                   
                 0 sec. after-flame 
               
               
                   
                   
               
             
          
         
       
     
     Example 6 
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
               
             
               
               
               
             
               
               
               
               
             
           
               
                   
               
               
                 Treatment of drapes (cotton fabric) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Polyacrylate dispersion 
                 500 
                 g/l 
               
               
                   
                 Water 
                 100 
                 g/l 
               
               
                   
                 Melamine polyphosphate 
                 50 
                 g/l 
               
               
                   
                 Application: 
               
             
          
           
               
                 1. 
                 Amount applied 
                 170 
                 g/m 2   
               
               
                 2. 
                 Process: Padding 
               
             
          
           
               
                 Liquor pick-up after pinch-off: about 70%, 
               
               
                 based on the fabric weight. 
               
             
          
           
               
                 3. 
                 Drying 
                 at 120° C. 
               
               
                 4. 
                 Crosslinking 
                 2 minutes at 170° C. 
               
             
          
           
               
                   
                 Flammability test: 
                   
                 Test methods as in DIN 4102 Part 1 
               
               
                   
                 Result: 
                 a) 
                 starting fabric - B1 passed 
               
               
                   
                   
                 b) 
                 after 5 washing procedures in a 
               
               
                   
                   
                   
                 washing machine with commercially 
               
               
                   
                   
                   
                 available detergent - B1 passed 
               
               
                   
                   
                 c) 
                 after 10 washing procedures - as 
               
               
                   
                   
                   
                 b) - B1 passed 
               
               
                   
                   
                 d) 
                 after 20 washing procedures - as 
               
               
                   
                   
                   
                 b) - B1 borderline, but very good 
               
               
                   
                   
                   
                 B2 result.