Silylated Polyurethanes, Their Preparation and Use

Abstract

A silylated polyurethane obtainable by a process comprising the following steps: (a) reacting at least one polyol with at least one triisocyanate to form a hydroxyl-terminated polyurethane prepolymer, and (b) reacting said polyurethane prepolymer with at least one isocyanatosilane of the formula (1): OCN—R—Si—(X)m(R1)3-m, wherein m is 0, 1 or 2, each R1 is independently from each other a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, or —OCH(R2)COOR3, wherein R2 is hydrogen or an alkyl group having 1 to 4 carbon atoms and R3 is a straight-chain or branched alkyl group having 1 to 8 carbon atoms, each X is independently from each other and optionally substituted hydrocarbon group having 1 to 10 carbon atoms, which can be interrupted by at least one heteroatom, and R is a difunctional organic group, to endcap the hydroxyl groups on said prepolymer with said isocyanatosilane. The silylated polyurethanes are suitable for use in a preparation as an adhesive, sealant, or coating agent.

1 . A silylated polyurethane obtained by a process comprising the following steps:
 (a) reacting at least one polyol with at least one triisocyanate to form a hydroxyl-terminated polyurethane prepolymer; and   (b) reacting the hydroxyl-terminated polyurethane prepolymer with at least one isocyanatosilane of formula (1) to endcap the hydroxyl groups on the hydroxyl-terminated polyurethane prepolymer with the isocyanatosilane,
   OCN—R—Si—(X) m (R 1 ) 3-m   (1)
 
   wherein
 m is 0, 1 or 2, 
 each R 1  is independently from each other a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, or —OCH(R 2 )COOR 3 , wherein R 2  is hydrogen or an alkyl group having 1 to 4 carbon atoms and R 3  is a straight-chain or branched alkyl group having 1 to 8 carbon atoms, 
 each X is independently from each other an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, which can be interrupted by at least one heteroatom, and 
 R is a difunctional organic group. 
   
     
     
         2 . The silylated polyurethane according to  claim 1 , wherein a molar ratio of the NCO groups of the triisocyanate to hydroxyl groups of the polyol is from 0.05 to 0.45. 
     
     
         3 . The silylated polyurethane according to  claim 1 , wherein said polyol is a polyether polyol. 
     
     
         4 . The silylated polyurethane according to  claim 1 , wherein said polyol has a number average molecular weight of from 500 to 20,000 g/mol. 
     
     
         5 . The silylated polyurethane according to  claim 1 , wherein said triisocyanate is derived from HDI, TDI, MDI, PDI, IPDI, or mixtures thereof. 
     
     
         6 . The silylated polyurethane according to  claim 1 , wherein said isocyanatosilane is selected from the group consisting of 3-isocyanatopropyltrimethoxysilane, 2-isocyanatoisopropyltrimethoxysilane, 4-isocyanato-n-butyltrimethoxysilane, 2-isocyanato-1,1-dimethylethyltrimethoxysilane, 1-isocyanatomethyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 2-isocyanato-2-methylethyltriethoxysilane, 4-isocyanatobutyltriethoxysilane, 2-isocyanato-1,1-dimethylethyltriethoxysilane, 1-isocyanatomethyltriethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropyldimethylmethoxysilane, 3-isocyanatopropylphenylmethylmethoxysilane, 1-isocyanatomethylmethyldimethoxysilane, 3-isocyanatopropylethyldiethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 1-isocyanatomethylmethyldiethoxysilane, and mixtures thereof. 
     
     
         7 . The silylated polyurethane according to  claim 1 , wherein said process comprises further step of adding a catalyst. 
     
     
         8 . A process for preparing a silylated polyurethane comprising the following steps:
 (a) reacting at least one polyol with at least one triisocyanate to form a hydroxyl-terminated polyurethane prepolymer; and   (b) reacting the hydroxyl-terminated polyurethane prepolymer with at least one isocyanatosilane of formula (1) to endcap the hydroxyl groups on the hydroxyl-terminated polyurethane prepolymer with the isocyanatosilane,
   OCN—R—Si—(X) m (R 1 ) 3-m    (1)
 
   wherein
 m is 0, 1 or 2, 
 each R 1  is independently from each other a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, or —OCH(R 2 )COOR 3 , wherein R 2  is hydrogen or an alkyl group having 1 to 4 carbon atoms and R 3  is a straight-chain or branched alkyl group having 1 to 8 carbon atoms, 
 each X is independently from each other an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, which can be interrupted by at least one heteroatom, and 
 R is a difunctional organic group. 
   
     
     
         9 . An adhesive, sealant, or coating composition comprising the silylated polyurethane according to  claim 1 . 
     
     
         10 . A silylated polyurethane that is the reaction product of a mixture comprising:
 (a) the hydroxyl terminated polyurethane prepolymer reaction product of a mixture comprising at least one polyol and at least one triisocyanate; and   (b) at least one isocyanatosilane of formula (1)
   OCN—R—Si—(X) m (R 1 ) 3-m   (1)
 
   
       wherein
 m is 0, 1 or 2, 
 each R 1  is independently from each other a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, or —OCH(R 2 )COOR 3 , wherein R 2  is hydrogen or an alkyl group having 1 to 4 carbon atoms and R 3  is a straight-chain or branched alkyl group having 1 to 8 carbon atoms, 
 each X is independently from each other an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, which can be interrupted by at least one heteroatom, and 
 R is a difunctional organic group.