Organometallic compositions and polyisocyanate compositions containing them

Abstract

An organometallic composition, suitable for use in curing polyisocyanate compositions, comprises a complex of at least one metal selected from iron, cobalt and aluminium and at least one β-dicarbonyl compound wherein when the metal is iron (II) or cobalt (II) the molar ration of β-dicarbonyl compound to metal is in the range from 2.1:1 to 10:1, and when the metal is aluminium (III), iron (III) or cobalt (III) the molar ration of β-dicarbonyl compound to metal is in the range from 3.1:1 to 10:1. A polyisocyanate composition containing the claimed organometallic composition and a process for binding lignocellulosic material is also described and claimed.

1 . A process for the formation of a polyurethane by the reaction of a polyisocyanate with a polyol in the presence of a catalyst composition comprising an organometallic composition, suitable for use in curing polyisocyanate compositions, comprising a complex of 
 (i) at least one metal selected from the group consisting of iron, aluminium and cobalt;    (ii) a β-dicarbonyl compound selected from benzoyl acetone, dibenzoylmethane, 2,2,6,6-tetramethylheptanedione, 1,1,1 -trifluoro-2,4-pentanedione, or a β-ketoester; and    (iii) optionally, a second β-dicarbonyl compound;    wherein, when the metal is iron (II) or cobalt (II), the molar ratio of total β-dicarbonyl compound to metal is in the range from 2.1:1 to 10:1, and when the metal is aluminium (III) iron (III) or cobalt (III), the molar ratio of total β-dicarbonyl compound to metal is in the range from 3.1:1 to 10:1.    
   
   
       2 . The process according to  claim 1 , wherein the molar ratio of total_β-dicarbonyl compound to metal is in the range 3.5:1 to 8:1.  
   
   
       3 . The process according to  claim 1 , wherein the β-dicarbonyl compound is a β-diketonate or a β-ketoester.  
   
   
       4 . The process according to  claim 3 , wherein the β-dicarbonyl compound is selected from acetylacetone, benzoyl acetone, dibenzoylmethane, 2,2,6,6-tetramethylheptanedione, 1,1,1-trifluoro-2,4-pentanedione, ethylacetoacetate, methylacetoacetate, isopropylacetoacetate or tertiarybutylacetoacetate.  
   
   
       5 . The process according to  claim 1 , wherein the composition comprises one β-dicarbonyl compound.  
   
   
       6 . The process according to  claim 1 , wherein the composition comprises more than one β-dicarbonyl compound.  
   
   
       7 . The process according to  claim 1 , wherein the complex is prepared by reacting an alkoxide or condensed alkoxide of aluminium with one or more β-dicarbonyl compound.  
   
   
       8 . The process according to  claim 1 , wherein the complex is prepared by reacting a halide, hydroxide or salt of iron, cobalt or aluminium with one or more β-dicarbonyl compound.  
   
   
       9 . A polyisocyanate composition comprising an organometallic composition, comprising a complex of: 
 (i) at least one metal selected from the group consisting of iron, aluminium and cobalt;    (ii) a β-dicarbonyl compound selected from benzoyl acetone, dibenzoylmethane, 2,2,6,6-tetramethylheptanedione, 1,1,1-trifluoro-2,4-pentanedione, or a β-ketoester; and    (iii) optionally, a second β-dicarbonyl compound;    wherein, when the metal is iron (II) or cobalt (II), the molar ratio of total β-dicarbonyl compound to metal is in the range from 2.1:1 to 10:1, and when the metal is aluminium (III) iron (III) or cobalt (III), the molar ratio of total β-dicarbonyl compound to metal is in the range from 3.1:1 to 10:1.    
   
   
       10 . The polyisocyanate composition according to  claim 9 , wherein the amount of organometallic composition present is in the range 0.01 to 20 per cent by weight.  
   
   
       11 . The polyisocyanate composition according to  claim 9 , wherein the polyisocyanate is diphenylmethane diisocyanate or a mixture of methylene bridged polyphenyl polyisocyanates.  
   
   
       12 . The polyisocyanate composition according to  claim 9 , wherein the composition contains a release agent in an amount in the range 0.2 to 10 per cent by weight.  
   
   
       13 . The polyisocyanate composition according to  claim 12 , wherein the release agent is a polysiloxane, a fatty acid, a fatty acid amide, a fatty acid ester or a polyolefin wax.  
   
   
       14 . The polyisocyanate composition according to  claim 9 , wherein the composition contains a diluent.  
   
   
       15 . A process for binding lignocellulosic material comprising the steps of: 
 a) bringing said lignocellulosic material in contact with a polyisocyanate composition according to  claim 9 , and    b) subsequently allowing said material to bind.    
   
   
       16 . The process according to  claim 15 , wherein the polyisocyanate composition is brought into contact with the lignocellulosic material and the combination thereby formed is hot-pressed at a temperature in the range 150° C. to 250° C. and 2 to 6 MPa specific pressure.  
   
   
       17 . The process according to  claim 15 , wherein the polyisocyanate composition is applied in an amount to give a weight ratio of polyisocyanate to lignocellulosic material in the range 0.1:99.9 to 20:80.  
   
   
       18 . The process according to  claim 15 , wherein a release agent is applied to the surface of the polyisocyanate treated lignocellulosic material or to the press metal surface prior to hot pressing the combination.