Patent GB-700609-A (GB)
Title: Improved polymeric materials obtained from di-isocyanate-modified polyesters
IPC: C08G18/10
Filed: 1950-01-16
Abstract: Elastomeric diisocyanate-modified polyesters which can be handled in the liquid phase are made by reacting an anhydrous polyester containing free hydroxyl groups with a diisocyanate in an amount of from 20 per cent. to 100 per cent in excess of that equivalent to the hydroxyl groups of the polyester, and adding to the reaction product a diamine or amino-alcohol in an amount less than that equivalent to the free isocyanate groups in the modified polyester, the diisocyanate and amino compound being so chosen that reaction between them in boiling methylene chloride causes no turbidity within 25 seconds.  Sufficient time is thus obtained after mixing the amino-compound with the modified polyester to enable the mixture to be cast or moulded in liquid form before solidifying.  The cast products are cured by heating to between 50 DEG  and 200 DEG C. for a few or several hours.  In the choice of reactants advantage is taken of the greater reactivity of aromatic diisocyanates compared with aliphatic diisocyanates, and the greater reactivity of aliphatic diamines compared with aromatic diamines, particularly those containing chloro- and nitro-groups. In examples: (1) A glycol - adipic acid polyester was reacted with 1.5 naphthalene diisocyanate, the product mixed with o-dichlorobenzidine and the mixture poured into moulds and heated for 10 hours at 100 DEG C. to give a rubber-like material: (2) a mixture of a glycoladipic acid ester and a propylene glycol adipic acid ester was reacted with naphthalene diisocyanate, the product mixed with o - dichlorobenzidine and the mixture cast into a rotating cycle tyre mould.  The tyre was removed after 20 minutes and cured at 100 DEG C. for 5-6 hours: (3) as in (2) using toluylene diisocyanate: (4) as in (2) using a glycoladipic acid ester alone: (5) a mixture of glycol and propylene glycol - adipic acid esters was reacted with hexamethylene diisocyanate, the product mixed with toluylene diamine and the mixture poured into moulds and heated at 100 DEG C for 12 hours to give transparent, rubbery products: (6) glycol - adipic acid ester, toluylene diisocyanate and dianisidine: (7) glycol - adipic acid ester, toluylene diisocyanate and o-dichlorobenzidine, the product being a foil: (8) glycol - adipic acid ester, naphthalene diisocyanate and 3 aminophenyl - ethanol: In all examples the polyesters had hydroxyl numbers of about 50 and acid numers about 1.  The Specification refers to the production of shoe soles, balls and packings as well as cycle tyres and foils.  Specifications 553,733 and 700,611 are referred to.ALSO:A mixture of a diisocyanate-modified polyester and a diamine or amino-alcohol (see Group IV (a)) is cast in the liquid state into a rotating drum heated to 100 DEG C., the inside of the drum being provided with the profile of a bicycle tyre.  After about 10 minutes the contents of the drum are solid and after a further 20 minutes the tyre can be taken out.  The moulded tyre is cured in a drying chamber at 100 DEG C. for 5-6 hours.  The Specification gives values for various physical properties of the moulded material using various starting mixtures.