Novel polyether polyol blends, a process for their preparation, foams prepared from these polyether polyol blends and a process for their preparation

A viscoelastic foam comprising the reaction product of:

• (A) toluene diisocyanate,
• with
• (B) an isocyanate-reactive component comprising a polyether polyol blend,
• in the presence of:
• (C) a blowing agent;
• (D) a catalyst;
• and
• (F) a surfactant,
• wherein the polyether polyol blend has an overall hydroxyl number of 56 mg KOH/g to 140 mg KOH/g, an overall functionality of greater than 2, and an overall content of copolymerized oxyethylene of 20% to 40% by weight, and comprises:
• (a) a monol initiated oxyalkylene ether having a hydroxyl number of less than or equal to 56 mg KOH/g polyol, and containing less than or equal to 20% of copolymerized oxyethylene, based on the total weight of monol initiated oxyalkylene ether (a);
• (b) a polyether polyol having a hydroxyl number of 47 mg KOH/g to 300 mg KOH/g, and a nominal functionality of 2, wherein the polyether polyol comprises a first oxide block containing 20% to 50% by weight of copolymerized oxyethylene, based on the weight of the polyether polyol at the end of the first oxide block, and a second oxide block comprising 10% to 50% by weight of copolymerized oxyethylene, based on the weight of the second oxide block;
• and
• (c) a polyether polyol having a hydroxyl number of 47 mg KOH/g to 300 mg KOH/g, and a nominal functionality of greater than 2 to 8, wherein the polyether polyol comprises a first oxide block having 20% to 50% by weight of copolymerized oxyethylene, based on the weight of the polyether polyol at the end of the first oxide block, and a second oxide block comprising 10% to 50% by weight of copolymerized oxyethylene, based on the weight of the second oxide block;
• wherein the polyether polyol blend comprises (i) from 20% to 50% by weight of (a) said monol initiated oxyalkylene ether, and (ii) from 80 to 50% by weight of polyether polyols (b) and (c), with the sum of the %' s by weight of (i) and (ii) totaling 100% by weight of the polyether polyol blend, and wherein (ii) the 80 to 50% by weight of polyether polyols (b) and (c) comprises polyether polyol (b) in an amount of 10 to 90% by weight and polyether polyol (c) in an amount of 90 to 10% by weight;
• and
• with the proviso that the isocyanate-reactive component does not include a polymer polyol.

A process for the preparation of a viscoelastic foam comprising reacting:

• (A) toluene diisocyanate,
• with
• (B) an isocyanate-reactive component comprising a polyether polyol blend,
• in the presence of:
• (C) a blowing agent;
• (D) a catalyst;
• and
• (E) a surfactant,
• wherein the polyether polyol blend has an overall hydroxyl number of 56 mg KOH/g to 140 mg KOH/g, an overall functionality of greater than 2, and an overall content of copolymerized oxyethylene of 20% to 40% by weight, and comprises:
• (a) a monol initiated oxyalkylene ether having a hydroxyl number of less than or equal to 56 mg KOH/g polyol, and containing less than or equal to 20% of copolymerized oxyethylene, based on the total weight of monol initiated oxyalkylene ether (a);
• (b) a polyether polyol having a hydroxyl number of 47 mg KOH/g to 300 mg KOH/g, and a nominal functionality of 2, wherein the polyether polyol comprises a first oxide block containing 20% to 50% by weight of copolymerized oxyethylene, based on the weight of the polyether polyol at the end of the first oxide block, and a second oxide block comprising 10% to 50% by weight of copolymerized oxyethylene, based on the weight of the second oxide block;
• and
• (c) a polyether polyol having a hydroxyl number of 47 mg KOH/g to 300 mg KOH/g, and a nominal functionality of greater than 2 to 8, wherein the polyether polyol comprises a first oxide block having 20% to 50% by weight of copolymerized oxyethylene, based on the weight of the polyether polyol at the end of the first oxide block, and a second oxide block comprising 10% to 50% by weight of copolymerized oxyethylene, based on the weight of the second oxide block;
• wherein the polyether polyol blend comprises (i) from 20% to 50% by weight of (a) said monol initiated oxyalkylene ether, and (ii) from 80 to 50% by weight of polyether polyols (b) and (c), with the sum of the %' s by weight of (i) and (ii) totaling 100% by weight of the polyether polyol blend, and wherein (ii) the 80 to 50% by weight of polyether polyols (b) and (c) comprises polyether polyol (b) in an amount of 10 to 90% by weight and polyether polyol (c) in an amount of 90 to 10% by weight;
• and
• with the proviso that the isocyanate-reactive component does not include a polymer polyol.