Flexible polyurethane foam

Abstract

The present invention provides a flexible polyurethane foam having good resistance to wet heat aging and resistance to ozone deterioration and a speaker edge having an excellent waterproofness comprising such a flexible polyurethane foam. As a polyol, a polyol component obtained by mixing a polyester polyol having an excellent compatibility with polyether polyol such as adipate of a long-chain alkylene glycol having at least 5 carbon atoms with a foaming agent, a catalyst, a foam stabilizer, etc. is reacted with a polyisocyanate to obtain a flexible polyurethane foam having good resistance to wet heat aging and resistance to ozone deterioration. Further, the incorporation of a specific aromatic secondary amine compound, a monofunctionally-terminated compound and an ultraviolet absorbent in the foam composition makes it possible to obtain a flexible foam having better resistance to ozone deterioration and weather resistance. The flexible foam can provide a speaker edge having a small drop of strength and elongation due to compression molding and excellent waterproofness and weather resistance in combination.

What is claimed is:  
     
         1 . A flexible polyurethane foam obtained by the reaction of a composition comprising a polyisocyanate and a polyol component, wherein the polyol component contains polyether polyol and polyester polyol between ester bonds, said polyester polyol having at least one of (i) a hydrocarbon group having at least 5 carbon atoms and (ii) a group having a hydrogen atom bonded to a skeleton containing at least 5 atoms consisting of carbon atoms and hetero atoms.  
     
     
         2 . The flexible polyurethane foam as claimed in  claim 1 , wherein the proportion of the polyester polyol is not more than 50% by weight based on 100% by weight of the sum of the content of the polyester polyol and the polyether polyol.  
     
     
         3 . The flexible polyurethane foam as claimed in  claim 1 , wherein the polyol component contains a hydroxyl compound having an ether bond and an ester bond per molecule.  
     
     
         4 . The flexible polyurethane foam as claimed in  claim 1 , wherein the polyol component contains a polyester polyol having a secondary terminal hydroxyl group.  
     
     
         5 . The flexible polyurethane foam as claimed in  claim 1 , wherein the polyol component contains a polymer polyol.  
     
     
         6 . The flexible polyurethane foam as claimed in  claim 1 , wherein the composition contains an aromatic secondary amine compound in an amount of from 1 to 25 parts by weight based on 100 parts by weight of the polyol contained in the polyol component.  
     
     
         7 . The flexible polyurethane foam as claimed in  claim 1 , wherein the composition comprises a monofunctionally-terminated compound having at least one of 
 (i) a hydrocarbon group having at least 5 carbon atoms and    (ii) a group having a hydrogen atom bonded to a skeleton containing at least 5 atoms consisting of carbon atoms and hetero atoms at one end of the molecular chain or a middle portion thereof and an active group reactive with the isocyanate group contained in the polyisocyanate or an active group reactive with an active hydrogen group contained in the polyol contained in the polyol component (these active groups are bonded to the carbon atom at the end of the molecular chain or the carbon atom adjacent to the terminal carbon atom) at the other end thereof.    
     
     
         8 . The flexible polyurethane foam as claimed in  claim 1 , which is used as a speaker edge.  
     
     
         9 . A flexible polyurethane foam obtained by the reaction of a composition comprising a polyisocyanate and a polyol component, wherein the polyol component contains at least one of a hydroxyl compound having an ether bond and an ester bond per molecule and a polyester polyol having a secondary terminal hydroxyl group and a polyether polyol.  
     
     
         10 . The flexible polyurethane foam as claimed in  claim 9 , wherein the polyol component contains a polymer polyol.  
     
     
         11 . The flexible polyurethane foam as claimed in  claim 9 , wherein the composition contains an aromatic secondary amine compound in an amount of from 1 to 25 parts by weight based on 100 parts by weight of the polyol contained in the polyol component.  
     
     
         12 . The flexible polyurethane foam as claimed in  claim 9 , wherein the composition comprises a monofunctionally-terminated compound having at least one of 
 (i) a hydrocarbon group having at least 5 carbon atoms and    (ii) a group having a hydrogen atom bonded to a skeleton containing at least 5 atoms consisting of carbon atoms and hetero atoms at one end of the molecular chain or a middle portion thereof and an active group reactive with the isocyanate group contained in the polyisocyanate or an active group reactive with an active hydrogen group contained in the polyol contained in the polyol component (these active groups are bonded to the carbon atom at the end of the molecular chain or the carbon atom adjacent to the terminal carbon atom) at the other end thereof.    
     
     
         13 . The flexible polyurethane foam as claimed in  claim 9 , which is used as a speaker edge.