Patent GB-767017-A (GB)
Title: Improvements in and relating to the production of diisocyanate-modified polyesters, polyesteramides and polyethers
Inventor: VINCENT MERVYN FREDERICK
IPC: C08G18/10
Filed: 1953-12-04
Abstract: The storage properties of diisocyanate-modified polyesters, polyesteramides or polyethers containing free isocyanate groups is improved by the addition of a tertiary alcohol, secondary aromatic amine, mercaptan, lactam, monohydric phenol, imide or compound containing enolizable hydrogen.  The compound added may form an adduct with the free isocyanate groups.  The stabilized material may be cured by heating in the presence of a basic catalyst such as an inorganic hydroxide or tertiary amine, or by heating in the presence of a compound containing two or more groups reactive with isocyanates such as water, ammonia, glycols, diamines, dicarboxylic acids, hydroxy amines, hydroxycarboxylic acids and aminocarboxylic acids. If the stabilizer forms an adduct the quantity used should not be in exess of that equivalent to the free isocyanate groups.  If the stabilizer does not form an adduct the quantity used should be from 0.5 to 6 per cent by weight of the isocyanate-modified polymer.  In the reaction between the isocyanate and polymer water should be excluded but the presence of 0.1 per cent of water by weight of the reaction mixture may be tolerated.  The additional polyfunctional reactant, if used, should be incorporated at a temperature below 130 DEG  C. to prevent premature curing, particularly when the reactant is added before storage.  If the reactant is water or ammonia it may be blown (in the form of vapour) on to the surface of or into the composition. Water may be incorporated as water of crystallization or by uptake from the air.  The final cure with the use of the additional polyfunctional reactant may be accelerated by the presence of pyridine.  Conventional additives such as fillers, plasticisers and pigments may be incorporated before the final cure.  In examples: (1) 5.84 parts of succinimide were added to 100 parts polyethylene adipate modified with 18.5 parts of 1.5 naphthalene diisocyanate, followed by 1.73 parts butane diol.  The first addition was made at 130 DEG  C. and the second at 80 DEG  C.  After storing a fortnight the product was cured by pressing for 1 hour at 160 DEG  C. and heating for 15 hours at 120 DEG  C.; (2) similar to (1) but using 2.75 parts succinimide and 1.5 parts butane diol; (3) to (8) similar to (2) but using respectively, instead of succinimide, phenol, tertiary amyl alcohol, caprolactam, mercaptobenzthiazole, diphenylamine and aceto-acetic ester; (9) 3.8 parts succinimide added to 100 parts polytetrahdrofurane modified with 12.12 parts 1.5 naphthalene diisocyanate followed by 1.04 parts butane diol. The product was cast into a flat sheet at 80 DEG  C., exposed to the air overnight after cooling and stored for a fortnight, after which it was cured by pressing for 10 minutes at 150 DEG  C. and further heating for 2 hours at 100 DEG  C.; (10) 3.14 parts caprolactam added to 100 parts polyethylene adipate modified with 14.56 parts 1.5 naphthalene diisocyanate and the product cooled to below 80 DEG  C. under reduced pressure.  0.2 parts beryllium hydroxide were then incorporated and the mixture cast into a sheet.  After exposure overnight the product was stored for 10 days and then cross-linked by pressing for one hour at 150 DEG  C., followed by heating at 120 DEG C. for 10 hours.  The Specification states that expanded products may be obtained by heating in a suitable mould compositions in which water is present as cross-linking agent.