Patent GB-815168-A (GB)
Title: Improvements in or relating to polymeric products
IPC: C08G18/10
Filed: 1957-01-14
Abstract: The Specification comprises polymers of the recurring formula: -[-HN-R-NH-]-Q-[-HN-V-NH-Q1-]n-where R is a bivalent polymeric radical which may be saturated having a molecular weight of at least 750 and obtainable by the polymerization of ethylenically unsaturated monomer at least 50 per cent by weight of which is a conjugated diene said monomer being a hydrocarbon or halohydrocarbon, V is a bivalent organic radical inert to isocyanate groups, Q and Q1 are carbonyl or non-polymeric diacyl radicals, and n is an integer or zero.  These polymers may be obtained by modifying polymeric material of the formula H2N-R-NH2 by reaction with carbonyl chloride, an organic diacid halide or an organic diisocyanate to which latter may be added a small amount of an organic triamine. Reaction with phosgene yields a polyurea of the formula: <FORM:0815168/IV (a)/1> reaction with a diacyl halide, e.g.: <FORM:0815168/IV (a)/2> yields a polymeric material of the formula: <FORM:0815168/IV (a)/3> and the diisocyanate V(NCO)2 yields the polyurea: <FORM:0815168/IV (a)/4> In these formulae -Y-X-Y- is a bivalent radical obtained by removing the terminal halogen atoms from the diacyl halide, Y being carbonyl or sulphonyl.  If excess isocyanate is used then an isocyanate-terminated compound is formed which may be chain extended and may be represented by the formula: <FORM:0815168/IV (a)/5> This may be chain extended by compounds containing two active hydrogen atoms such as water, hydrogen sulphide and organic compounds containing two active hydrogen atoms capable of reacting with isocyanate groups.  Suitable groups containing such an active hydrogen atom are -OH, -NH2, -SH, -COOH, -CONH2, -CSNH2, -SO2NH2 and -SO2OH.  The polymeric diamine starting material has a molecular weight of 750-12,000 and is preferably prepared by polymerizing butadiene, isoprene, 2,3-dimethylbutadiene, chloroprene, fluoroprene or bromoprene, or copolymerizing such dienes with styrene or isobutylene, in the presence of aliphatic azo dinitriles such as a ,a 1-azo diisobutyronitrile.  The result is a polymer terminated at each end by the radical -C(CH3)2-CN produced from the free radical of the polymerizing catalyst. These end groups may be reduced with LiAlH4 to amino groups without reducing unsaturation in the polymer chain or the whole polymer may be hydrogenated to give a fully saturated diamine. The polymeric diamine may, however, be prepared also by conventional synthetic methods such as converting a long chain dicarboxylic acid to the corresponding omega-bromo monocarboxylic acid, doubling the chain by bromine elimination and repeating as desired, finally converting the dicarboxylic acid to a diamine. Linking agents which may be used are diacyl chlorides such as adipyl chloride, sebacyl chloride, butane-1,4-disulphonyl chloride, oxalyl chloride, maleyl chloride and terephthalyl chloride or the corresponding bromides.  A molecular ratio to the polymeric diamine between 0.5 : 1 and 1 : 1 may be used.  Organic diisocyanate linking agents specified are the diisocyanates of the following radicals: 2,4-tolylene, 2,6-tolylene, m-phenylene, 4-chloro-1,3-phenylene, 4,41-biphenylene, 1,5-naphthylene, tetramethylene, hexamethylene, decamethylene, 1,4-cyclohexylene, 4,41-methylene-bis-(cyclohexyl) and 1,5-tetrahydronaphthylene, and dimers of monomeric diisocyanates and di-(3-isocyanato-4-methylphenyl) urea, and may be used in the form of their reaction products with phenols and related mercapto compounds such as mercapto-benzothiazole or other reaction products which regenerate the diisocyanate on heating.  Specified organic chain extending agents for isocyanate-terminated polymers are ethylene glycol, hexamethylene glycol, diethylene glycol, adipic acid, terephthalic acid, adipamide, 1,2-ethanedithiol, hydroquinone, monoethanolamine, 4-aminobenzoic acid, m-phenylene diamine, trimethylene diamine, 4-aminobenzamide, sulphanilamide, b -aminopropionic acid, 1,4-cyclohexanedisulphonamide, 1,3-propanedisulphonamide, 4-hydroxybenzoic acid, p-aminophenol, ethylene diamine, succinic acid, succinamide, 1,4-butane-disulphonamide, 2,4-tolylene diamine, bis-(4-aminophenyl) methane, b -hydroxypropionic acid and 1,2-ethanedisulphonic acid. When using chain extenders which liberate carbon dioxide with the isocyanate the reaction may be controlled to produce a solid foam. The chain extended product should have at least 60 per cent by weight as polymeric diamine radicals.  When preparing the linked polymers a low molecular weight diamine such as hexamethylene diamine may also be added, particularly when preparing filaments from the reaction of the polymeric diamine with a diacyl halide.  When phosgene is the linking agent the reaction is preferably carried out in an inert hydrocarbon solvent at 0-50 DEG  C. in the presence of a basic material to combine with the hydrogen chloride such as inorganic hydroxides and carbonates and organic amines.  The molecular ratio of phosgene to polymeric diamine should be at least 0.8 : 1 and is preferably between 1.5 : 1 and 3 : 1.  The reaction with diisocyanate is preferably carried out in a hydrocarbon solvent at low temperatures, e.g. down to - 70 DEG  C. and the temperature may be raised to 100 DEG  C. during the later stages.  When then the diisocyanate is added as an addition compound which regenerates diisocyanate on heating the reaction mixture must be heated to effect coupling.  The diisocyanate reaction is accelerated by the salt of an organic tertiary nitrogen or phosphorus base such as pyridine and the presence of such a compound is useful during the subsequent chain-extension step if performed.  The molecular ratio of diisocyanate to polymeric diamine should be at least 0.8 : 1 and may be as high as 12 : 1 when a chain-extension is to be performed.  The most useful range is 1.2 : 1 to 3 : 1.  An excess of diisocyanate is desirable even when chain-extension is not to take place.  Products containing free isocyanate groups may be stabilized by addition of a nitrogen base having at least one hydrogen attached to the nitrogen. The products may be cured by joining the polymer chains with each other at the urea or other active groups by reaction with diisocyanate, or where the polymeric hydrocarbon chain of the diamine is still unsaturated curing may be effected by conventional methods. When the former method is used, products formed by linking with phosgene or a diacyl halide must have a diisocyanate added, products inked by the use of diisocyanate will need addition polyisocyanate if the product contains little or no free isocyanate groups, but if sufficient isocyanate groups are present this may not be necessary. Diisocyanates previously specified may be used in amounts of 1-20 per cent by weight based on the polymer.  The addition of a small amount of magnesium oxide is often useful.  Normal curing temperatures and pressures such as 80-175 DEG  C. and 50-1000 p.s.i. are used.  Curing may also occur at room temperature and pressure, particularly when the product is in a thin sheet, by allowing it to stand for several days.  Curing with sulphur is effected conventionally including the use of accelerators and other adjuvants.  Cured polymers may also be formed without the separation of an intermediate linked polymer by heating the polymeric diamine with a non-polymeric organic triamine and a diisocyanate having isocyanate groups which do not react at ordinary temperatures or a diisocyanate adduct which generates diisocyanate on heating.  Suitable triamines include diethylene triamine, 1,2,3-triamino propane and the triamino benzenes and toluenes, and should be used in an amount not exceeding 15 mols. per 100 mols. of polymeric diamine.  The uncured products may be obtained as filaments by melting, heating e.g. to 210 DEG  C. and forcing through a spinneret.  Films and coatings may be formed by pouring or otherwise applying a solution of a polymer linked with diisocyanate to form a thin film and allowing the solvent to evaporate.  If chain-extension has not taken place this may occur with moisture from the air; curing may also occur if sufficient free isocyanate groups are present or a curing agent may be added to the solution before forming the film.  The elastomeric properties may be varied by the addition of compounding agents normally used in the rubber industry.