Back to results
US 5,491,177 AGranted
Process for preparing a flexible polyurethane foam
AssigneeImperial Chemical Industries PLC
InventorMireille B. A. De Witte
Life of this patent
Estimating the term…
Abstract
Process for preparing a flexible foam by reacting a polyisocyanate composition having an NCO value of 11-22% by weight with an isocyanate-reactive compound having a number average molecular weight of 1000-12000 using water as blowing agent.
Claims10
A process for preparing a flexible polyurethane foam by reacting
- 1) an organic polyisocyanate with
- 2) a polyol having an average nominal hydroxyl functionality of 2-3 and a number average molecular weight of 1000 to 12000;
- and optionally with
- 3) an isocyanate-reactive compound containing at least two isocyanate-reactive hydrogen atoms and having a number average molecular weight of 60 to 999;
- using
- 4) a blowing agent;
- and optionally
- 5) a catalyst;
- and optionally
- 6) other auxiliaries and additives known per se characterised in that
- a) the polyisocyanate is a polyisocyanate composition having an NCO value of 11-22% by weight which is a blend of
- a1. 75-95 parts by weight of an isocyanate-terminated semi-prepolymer having an NCO value of 9-20% by weight, prepared by reacting an excessive amount of a polyisocyanate composition, consisting of 35-75% by weight of diphenylmethane diisocyanate and 25-65% by weight of polymethylene polyphenylene polyisocyanate, with a polyol having an average nominal hydroxyl functionality of 2-3 and a number average molecular weight of 1000 to 12000;
- and
- a2. 5-25 parts by weight of a polymethylene polyphenylene polyisocyanate;
- b) 25-120 parts by weight of polyol 2) is used per 100 parts by weight of organic polyisocyanate;
- c) water is used as blowing agent in an amount of 3-15 parts by weight per 100 parts by weight of polyol 2);
- and
- d) the reaction is conducted at an index of 40-130.
15 more elements
Reaction system comprising
- 1) an organic polyisocyanate;
- 2) a polyol having an average nominal hydroxyl functionality of 2-3 and a number average molecular weight of 1000 to 12000;
- and optionally
- 3) an isocyanate-reactive compound containing at least two isocyanate-reactive hydrogen atoms and having a number average molecular weight of 60 to 999;
- 4) a blowing agent;
- and optionally
- 5) a catalyst;
- and optionally
- 6) other auxiliaries and additives known per se characterised in that
- a) the polyisocyanate is a polyisocyanate composition having an NCO value of 11-22% by weight which is a blend of
- a1. 75-95 parts by weight of an isocyanate-terminated semi-prepolymer having an NCO value of 9-20% by weight, prepared by reacting an excessive amount of a polyisocyanate composition, consisting of 35-75% by weight of diphenylmethane diisocyanate and 25-65% by weight of polymethylene polyphenylene polyisocyanate, with a polyol having an average nominal hydroxyl functionality of 2-3 and a number average molecular weight of 1000 to 12000;
- and
- a2. 5-25 parts by weight of a polymethylene polyphenylene polyisocyanate;
- b) 25-120 parts by weight of polyol 2) is used per 100 parts by weight of organic polyisocyanate;
- c) water is used as blowing agent in an amount of 3-15 parts by weight per 100 parts by weight of polyol 2);
- and
- d) the relative amount of polyisocyanate 1) with respect to the other ingredients is such that when combined the index is 40-130;
- with the proviso that the polyisocyanate is kept in a container separate from the isocyanate-reactive compounds.
15 more elements
Organic polyisocyanate composition, characterised in that the composition has an NCO value of 11-22% by weight and is a blend of
- a1. 75-95 parts by weight of an isocyanate-terminated semi-prepolymer having an NCO value of 9-20% by weight, prepared by reacting an excessive amount of a polyisocyanate composition, consisting of 35-75% by weight of diphenylmethane diisocyanate and 25-65% by weight of polymethylene polyphenylene polyisocyanate, with a polyol having an average nominal hydroxyl functionality of 2-3 and a number average molecular weight of 1000 to 12000;
- and
- a2. 5-25 parts by weight of a polymethylene polyphenylene polyisocyanate.
Dependencies are inferred from the claim text.