Process for the production of polyurea based articles

A composition for a RIM process suited for the production of molded articles having a flexural modulus .gtoreq.80,000 p.s.i. comprising

• component A) an isocyanate quasi pre-polymer component comprising the reaction production of:
• i) a polyisocyanate, said polyisocyanate being a MDI or modified MDI having a free isocyanate content of from 20-33% by weight NCO;
• and
• ii) a polyether triol component having from 50-85% by weight ethylene oxide units and 15-50% by weight propylene oxide units;
• wherein said isocyanate quasi pre-polymer has a final NCO content of from 10-27%;
• and
• component B) a polyol component comprising:
• i) an amine terminated polyether polyol with functionality of 2 or 3 and having a number average molecular weight of 2,000-5,000;
• ii) a hydroxy terminated and amine started polyether polyol of 200-980 number average molecular weight;
• wherein said amine terminated polyether polyol (i) and said aromatic diamine (ii) are present in a ratio (i)/(ii) of at least 2:1 and said aromatic diamine (ii) and said hydroxy terminated and amine started polyether polyol (iii) are present in a ratio (ii)/(iii) of .gtoreq.2.1:1.

A method for forming a reinforced molded article with an A class surface comprising;

• 1) forming a first layer of a polymer molding composition comprising admixing a component A) and a component B) in a mold, reacting said component A) and said component B) in said mold wherein
• component A) is an isocyanate quasi pre-polymer component comprising the reaction product of:
• i) a polyisocyanate, said polyisocyanate being MDI or modified MDI having a free isocyanate content of from 20-33% by weight NCO;
• ii) a polyether triol component having from 50-85% by weight ethylene oxide units and 15-50% by weight propylene oxide units;
• wherein said isocyanate quasi pre-polymer has a final NCO content of from 10-27%;
• and
• component B)is a polyol component comprising:
• i) an amine terminated polyether polyol with functionality of 2 or 3 and having a number average molecular weight of 2,000-5,000;
• ii) an aromatic diamine;
• and
• iii) a hydroxy terminated and amine started polyether polyol of 200-800 number average molecular weight;
• wherein said amine terminated polyether polyol (i) and said aromatic diamine (ii) are present in a ratio (i)/(ii) of at least 2:1 and said aromatic diamine (ii) and said hydroxy terminated and amine started polyether polyol (iii) are present in a ratio (ii)/(iii) of .gtoreq.2.5:1 on at least one surface of a mold;
• ii) forming a second Layer on said first layer of a polymer molding composition by structural reaction injection molding.

A molded article comprising the reaction product of a polymer molding composition comprising admixing a component A) and a component B) in a mold, reacting said component A) and said component B) in said mold wherein

• component A) is an isocyanate quasi pre-polymer component comprising the reaction product of:
• i) a polyisocyanate, said polyisocyanate being MDI or a modified MDI having a free isocyanate content of from 20-33% by weight NCO;
• ii) a polyether triol component having from 50-85% by weight ethylene oxide units and 15-50% by weight propylene oxide units;
• wherein said isocyanate quasi pre-polymer has a final NCO content of from 10-27%;
• and
• component B) is a polyol component comprising:
• i) an amine terminated polyether polyol with functionality of 2 or 3 and having a number average molecular weight of 2,000-5,000;
• ii) an aromatic diamine;
• and
• iii) a hydroxy terminated and amine started polyether polyol of 200-800 number average molecular weight;
• wherein said amine terminated polyether polyol (i) and said aromatic diamine (ii) are present in a ratio (i)/(ii) of at least 2:1 and said aromatic diamine (ii) and said hydroxy terminated and amine started polyether polyol (iii) are present in a ratio (ii)/(iii) of >2.5:1.