High tear strength flexible urethane foam composition and method of preparation

A flexible closed cell polyurethane foam composition characterized by high tensile or tear strength and reduced shrinkage which foam composition is prepared by reacting:

• (a) an A side composition comprising 100 parts by weight of an MDI-polyol prepolymer, which prepolymer is prepared by reacting 100 parts of MDI having an average functionality of about 2.0 to 2.2 with from about 40 to 65 parts by weight of an ethylene oxide-capped polypropylene polyol with a B side composition comprising
• (b) from about 4 to 8 parts by weight of a tetraethylene glycol;
• (c) about 90 to 120 parts by weight of the ethylene oxide-capped polypropylene glycol polyol employed to prepare the prepolymer;
• and
• (d) the reaction carried out in the presence of about 1 to 15 parts by weight of a liquid fluorocarbon blowing agent;
• a catalytic amount of a co-catalyst system comprising an amine catalyst and a tetravalent organo-tin catalyst;
• a cell control amount of a silicone agent;
• a shrink reducing amount of a potassium fatty acid salt, and a cream time reducing amount of a lead fatty acid salt to reduce the cream time to less than about 1 second.

A flexible open cell polyurethane foam composition characterized by high tensile or tear strength and improved flame retardancy, which foam composition is prepared by reacting:

• (a) an A side composition comprising 100 parts by weight of an MDI-polyol prepolymer, which prepolymer is prepared by reacting 100 parts of MDI having an average functionality of about 2.0 to 2.2 with from about 40 to 65 parts by weight of an ethylene oxide-capped polypropylene polyol with a B side mixture comprising:
• (b) from about 4 to 8 parts by weight of a tetraethylene glycol;
• (c) about 90 to 120 parts by weight of the ethylene oxide-capped polypropylene glycol polyol employed to prepare the prepolymer:
• (d) the reaction carried out in the presence of about 0.5 to 5 parts by weight of water as a blowing agent, a catalytic amount of a co-catalyst comprising a diamine catalyst in combination and a tetravalent organo tin catalyst, a cell control amount of a silicone agent, and from about 2 to 12 parts by weight of MDI of a phosphate as a flame-retardant agent.