GB1575964A

GB1575964A - Diisocyanates a process for the preparation thereof and the use thereof

Info

Publication number: GB1575964A
Application number: GB40717/77A
Authority: GB
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1976-10-02
Filing date: 1977-09-30
Publication date: 1980-10-01
Also published as: BE859243A; DE2644640C2; ATA698277A; DE2644640A1; AT352102B; SE7710906L; ES462807A1; JPS5344549A; NL7710754A; FR2366263A1

Description

(54) DIISOCYANATES, A PROCESS FOR THE PREPARATION THEREOF AND THE USE THEREOF (71) We, BAYER AKTIENGESELLSCHAFT, a body corporate organised under the Laws of Germany, of 509 Leverkusen, Germany; do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to diisocyanates, a process for the preparation thereof and the use thereof.

Diisocyanates containing cycloaliphatically bound isocyanate groups, which are suitable for the production of light-fast polyurethane resins, have a low melting point, are physiologically substantially harmless because of the low vapour pressure thereof and which may be produced by simple and economical methods without complicated procedures, such as hydrogenation of aromatic compound, have not hitherto been known. Such diisocyanates are now made available by the present invention It has surprisingly been found that diamines which may be converted into the diisocyanates according to the present invention by phosgenation are obtainable from p-benzoquinone and p-benzoquinone derivatives, simple dienes and ammonia by reductive amination.

The diisocyanates according to the present invention are not only exceptionally valuable starting materials for the production of polyurethane resins, but are themselves valuable paper sizes when used in the form of aqueous dispersions without further chemical modification.

The present invention therefore relates to diisocyanates corresponding to the following general formula:

wherein n and m, which may be the same or different, each represents, 0, 1 or 2, preferably 0 or 1; R, R, and R2, which may be the same or different, and each represents hydrogen or methyl, R1 preferably representing hydrogen in the alkylene bridge (C, R, R1), provided that, when n and m each represents 0, then at least one of the R, R, and R2 represents other than hydrogen.

The present invention also relates to a process for the preparation of these diisocyanates, in which the corresponding diamines are subjected to the known phosgenation reaction.

The present invention further relates to the use of the present diisocyanates, which may be in the form of diisocyanates which are masked with suitable masking agents for the isocyanate groups, as isocyanate components for the production of polyurethane resins by the isocyanate polyaddition process.

Furthermore, the present invention also relates to the use of the present diisocyanates in the form of aqueous dispersions as paper sizing agents.

The diamines corresponding to the following general formula (I):

wherein n, m, R, R, and R2 are as defined above; which are to be used in the process according to the present invention for the preparation of the present diisocyanates, may be obtained by a hydrogenation reaction, in the presence of ammonia, of compounds corresponding to one of the following general formulae (II) or (IIa):

wherein n, m, R, R, and R2 are as defined above.

The hydrogenation reaction of compounds corresponding to the above general formula (II) is accompanied by reductive amination of the CO groups and addition of hydrogen to the C=C double bonds. The reduction is carried out in the presence of from 2 to 30 mol of ammonia per mol of (II), in particular from 3 to 15 mol of ammonia per mol of (11), at temperatures of from 30 to 1 800C and pressures of from 5 to 200 bar of hydrogen, in particular at from 60 to 1 500C and from 30 to 150 bar of hydrogen.

The conventional hydrogenation catalysts are used for this reaction. Catalysts containing an element or elements of Group VIII of the Periodic Table in the metallic or oxidized form, for example, are suitable. The catalytically active component may be used without carrier or it may be applied to a catalyst carrier.

Suitable carriers for the active components include, for example, alumina, charcoal, kieselguhr, bentonite, asbestos, silicates and zinc oxide. Examples of suitable catalysts include nickel, cobalt, rhodium, ruthenium and platinum catalysts, for example Raney nickel, Raney cobalt, nickel or keiselguhr having a nickel content of up to 60 /n by weight, cobalt oxide on kieselguhr, nickel chromite, and platinum on charcoal having a platinum content of from 0.1 to 5% by weight. Hydrogenation may be carried out with or without solvent. Suitable solvents for hydrogenation in solution include alcohols, ethers, cyclic ethers, such as tetrahydrofuran and dioxane, and hydrocarbons, such as cyclohexane, benzene, toluene and xylene. In some cases it may be advantageous to use a mixture of solvents. It is a particular advantage of the present process that reductive amination may be carried out in the same solvent as that used for preparation of the Diels-Alder adduct.

Preparation of the saturated Diels-Alder compound corresponding to above general formula (lea) is carried out in accordance with the method given by K.

Alder and G. Stein, in Annalen der Chemie, 501 (1933), pages 285, 286, 288, 289 and 293. Hydrogenation is first carried out in an inert solvent, such as ethyl alcohol, for example with the aid of colloidal palladium at room temperature under a hydrogen atmosphere so that the C=C double bonds are opened while the two keto groups are preserved. The saturated diketones (lea) are then reductively animated.

According to one particular method, both hydrogenation reactions may be carried out one after the other in a one shot process, in which the C=C double bonds of the starting compounds (II) are first reacted as indicated above and the keto groups are then reductively aminated in the same solvent without working-up the intermediate stage.

The two-stage process is preferable to the one-shot process in cases where quantitative hydrogenation of the olefinic double bonds is important.

The following are preferred examples of starting compounds (I) which may be used according to the present invention: 9,1 0-diamino- 1,4: 5,8-dimethano-tetradecahydroanthracene (III)

9,1 0-diamino- 1 ,4-methano-tetradecahydroanthracene (IV)

9,1 0-diamino- 1 ,4-methano-6-methyltetradecahydroanthracene (V)

9,1 0-diamino-2-methyl-tetradecahydroanthracene (VI)

9,10-diamino-2,6(or 2,7)-dimethyl-tetradecahydroanthracene (VII)

Corresponding compounds which have ethano bridges could also be used, but are less suitable, for example 9,10-diamino-1,4:5,8-diethano- tetradecahydroanthracene or 9,10-diamino-1,4-ethano-tetradecahydroanthracene. ,4-ethano-tetradecahydroanthracene.

The intermediate products (II) are prepared according to the known Diels Alder reaction, for example as follows: I mol of p-benzoquinone or a methyl-substituted quinone is reacted with 2 mol of the appropriate diene at normal pressure and at a temperature between 20 and 150"C in an inert solvent, preferably in toluene or methanol at temperatures between 50 and 100 C. The Diels-Alder product crystallises from the reaction solution on cooling or, if a considerable excess of solvent is used, the product is obtained by distillation of the solvent. This method is particularly suitable for the reaction of the above-mentioned quinones with cyclohexadiene-( 1,3) or cyclopentadiene.

The reactions may also be carried out under the autogenous pressure in the reactor, particularly in the case of butadiene, l-(or 2-)methyl butadiene or 2,3 dimethyl butadiene. In such cases, the addition reaction is carried out in an inert solvent, such as toluene or methanol, at a temperature of between 50 and 180 C, preferably between 120 and 1700C. The reaction product is obtained in a crystalline form or as a solution, depending on the concentration conditions, and if obtained as a solution, it is isolated by removal of the solvent by distillation.

When preparing mixed Diels-Alder products by the above-mentioned process (either without the application of pressure or under autogenous pressure), of I mol of the diene is first added to the quinone and thereafter, either after isolation of the mono-adduct or preferably without working-up of this stage, I mol of another diene is added under normal conditions or in the reactor under the particular conditions of solvent and temperature mentioned for the given process. The reaction products are then worked-up as indicated above.

Examples of suitable dienophiles used for preparation of the starting materials (II) include p-benzoquinone and methyl-substituted quinones, particularly 2 methylbenzoquinone, 2,3 - dimethylbenzoquinone, 2,5 - dimethylbenzoquinone and 2,6 - dimethylbenzoquinone. Suitable dienes include, for example, the following products: cyclopentadiene, methyl and dimethvl-cvclopentadiene (Monatshefte fir Chemie 89, 748--753' (1958)), cyclohexadiene-(l ,3), 1methylbutadiene, 2-methylbutadiene and 2,3-dimethylbutadiene.

The following are examples of preferred preliminary products leading to the diamines which are used for the preparation of the diisocyanates according to the present invention: 1,4:5,8 - dimethano - 1,4,4a,5,8,8a,9a,10a octahydroanthraquinone (VIII):

1,4 - methano - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (IX)

2 - methyl - 5,8 - methano - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (X):

2 - methyl - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (XI)

the sterlosomers 2,6 - (or 2,7) - dimethyl - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (XII)

as well as the corresponding saturated diketones.

In the process according to the present invention, the starting materials (I) are converted into the corresponding diisocyanates by phosgenation in known manner.

The following procedure may be employed: The diamine, which may be dissolved in a suitable solvent, such as chlorobenzene, is introduced dropwise with stirring, at from -20 to +50C, into a solution of phosgene in a suitable solvent, such as chlorobenzene. The reaction mixture is then slowly heated until the solvent boils while phosgene is introduced.

The reaction is continued until a clear solution is obtained. The diisocyanate is obtained from this solution by distillation. Suitable solvents for phosgenation include halogenated alkanes and cycloalkanes and halogenated aromatic compounds, particularly chlorobenzene and o-dichlorobenzene.

This general method of procedure converts the exemplified diamines into the corresponding preferred diisocyanates according to the present invention: 9,10 - diisocyanato - 1,4:5,8 - dimethano - tetradecahydroanthracene (XIII):

9,10 - diisocyanato - 1,4 - methano - tetradecahydroanthracene (XIV):

9,10 - diisocyanato - 1,4 - methano - 6 - methyl - tetradecahydroanthracene (XV):

9,10 - diisocyanato - 2 - methyl - tetradecahydroanthracene (XVI)

9,10 - diisocyanato - 2,6 - (or 2,7) - dimethyl - tetradecahydroanthracene (XVII):

or diisocyanates with ethano bridges, which are less suitable for the purposes of the present invention, are obtained from the corresponding diamines with ethano bridges exemplified above.

Apart from the above-mentioned advantages, the present diisocyanates have the particular advantage of being highly soluble in aliphatic hydrocarbons.

Polyurethanes and polyurethane polyureas produced from them are also more readily soluble than the corresponding polyurethanes or polyurethane ureas prepared, for example, from 4,4' - diisocyanato - dicyclohexylmethane.

For the preparation of polyurethanes, the present diisocyanates may be reacted with the conventional reaction components for polyisocyanates used in polyurethane chemistry either in the free form or after isocyanate groups thereof have been masked with blocking agents. The present diisocyanates are particularly suitable for the production of polyurethane lacquers.

Suitable blocking agents include for example, phenols, such as phenol, cresol or isononylphenol, oximes, such as butanone oxime or benzophenone oxime, lactams, such as caprolactam, alcohols, such as methanol, as well as ethyl acetoacetate, malonic acid esters and mercaptans. Bisulphite adducts of the present isocyanates may also be used.

Preparation of such blocked diisocyanates from the present diisocyanates is carried out by a method similar to the known method of preparing blocked polyisocyanates.

Reaction components with which the present polyisocyanates or the corresponding blocked polyisocyanates are reacted include, for example, compounds containing at least two hydrogen atoms which are reactive with isocyanates, these compounds generally having a molecular weight of from 400 to 10,000. Apart from compounds having amino groups, thiol groups or carboxyl groups, the compounds of this type are preferably polyhydroxyl compounds, in particular compounds having from 2 to 8 hydroxyl groups, and especially those having a molecular weight of from 800 to 10,000, preferably from 1000 to 6000, for example polyesters, polyethers, polythioethers, polyacetals, polycarbonates, polyester amides and polymers all containing at least two, generally from 2 to 8, preferably from 2 to 4 hydroxyl groups, of the type which are known for the production of both non-cellular and cellular polyurethanes.

Suitable hydroxyl polyesters include, for example, the reaction products of polyhydric, preferably dihydric, alcohols, to which trihydric alcohols may be added, and polybasic, preferably dibasic, carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid anhydrides or polycarboxylic acid esters of lower alcohols or mixtures thereof may be used for preparing the polyesters. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromic and/or heterocyclic and they may be substituted one or more times, for example by halogen atoms, and/or they may be unsaturated. The following are examples: adipic acid, phthalic acid, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride and tetrachlorophthalic acid anhydride. Examples of suitable polyhydric alcohols include: ethylene glycol, propylene glycol - (1,2) and -(1,3), butylene glycol - (1,4) and -(2,3), hexane diol (1,6), 2 - methyl - 1,3 - propane diol, glycerol, trimethylolpropane, hexane triol (1,2,6), diethylene glycol, triethylene glycol, dipropylene glycol, higher polypropylene glycols and polybutylene glycols. The polyesters may contain a proportion of carboxyl groups in end positions. Polyesters of lactones, e.g. E caprolactone, or hydroxycarboxylic acid, e.g. w-hydroxycaproic acid, may also be used.

Apart from these polyhydroxypolyesters, which are the particularly preferred reaction partners for the present diisocyanates, the known polyhydroxy polyethers of polyurethane chemistry are also preferred reaction partners for the present diisocyanates. Examples of such polyhydroxypolyethers include known polyethers having at least two, generally from 2 to 8, preferably 2 or 3, hydroxyl groups, which polyethers are prepared, for example, by the polymerisation of epoxides, such as ethylene oxide or propylene oxide, on their own, e.g. in the presence of boron trifluoride, or by addition of these epoxides, either as mixtures or successively, to starting components which have reactive hydrogen atoms, such as water, ammonia, alcohols or amines, e.g. ethylene glycol, propylene glycol - (1,3) or (1,2), trimethylolpropane, ethanolamine or ethylene diamine. Polyethers which have been modified with vinyl polymers, e.g. the compounds obtained by the polymerisation of styrene or acrylonitrile in the presence of polyethers as described in U.S. Patent Nos. 3,383,351; 3,304,273; 3,523,093; and 3,110,695 and German Patent No. 1,152,536, and also hydroxyl group-containing polybutadienes or polycarbonates are also suitable.

The polycarbonates containing hydroxyl groups may be of known type, for example those prepared by the reaction of diols, such as propane diol - (1,3), butane diol - (1,4) and/or hexane diol - (1,6), diethylene glycol, triethylene glycol or tefraethylene glycol, with diarylcarbonates, e.g. diphenylcarbonate, or with phosgene.

Representatives of these compounds which may be used according to the present invention have been described, for example, in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology", by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32 to 42 and pages 44 to 54 and Volume II, 1964, pages 5-6 and 198-199 and in Kunststoff-Handbuch, Volume VII, Vieweg-Hchtlen, Carl-Hanser Verlag Munich, 1966, e.g. on pages 45-71.

Vinyl polymers which have hydroxyl groups may also be used as reaction components for the present diisocyanates. These include the known copolymers of ethylenically unsaturated monomers which have hydroxyl groups with other ethylenically unsaturated compounds, e.g. ethylenically unsaturated esters and hydrocarbons. Copolymers which contain the following hydroxyl monomers should be particularly mentioned: monohydroxy- and polyhydroxy-alkylmaleates and fumarates, such as hydroxyethyl fumarate, hydroxyl acrylates, and hydroxyl methacrylates, such as trimethylolpropane monomethacrylate, 2 hydroxyethylacrylate and methacrylate, 2 - (or 3-)hydroxy - propyl - acrylate and -methacrylate, 4 - hydroxybutyl - acrylate and -methacrylate and hydroxyl vinyl compounds, such as hydroxyether vinyl ether and allyl alcohols.

Suitable comonomers for the preparation of the above-mentioned copolymers include, for example, methyl methacrylate, ethyl methacrylate, methyl acrylate and ethyl acrylate.

Mono-olefinic hydrocarbons and chlorinated hydrocarbons, such as styrene, a - methylstyrene or a - chlorostyrene, and mono - olefinic nitriles, such as acrylonitrile and methacrylonitrile, may also be used as comonomers.

In addition, polymers which contain acid groups and have been obtained by copolymerisation of unsaturated acids, such as maleic acid, acrylic acid or methacrylic acid, may be used in lacquers.

When the present diisocyanates or the corresponding blocked diisocyanates are used in two-component polyurethane laquers in accordance with the present invention, they may be combined not only with the aforementioned relatively high molecular weight polyhydroxyl compounds, but also with various low molecular weight polyols having a molecular weight of from 62 to 400. It is frequently advisable to use mixtures of the aforesaid relatively high molecular weight polyhydroxyl compounds with such low molecular weight polyhydroxyl compounds. The NCO/OH ratio in the two-component polyurethane lacquers is generally between 0.8:1 and 1.2:1.

Suitable low molecular weight polyhydroxyl compounds within the abovementioned molecular weight range include in particular diols and/or triols having aliphatically or cycloaliphatically bound hydroxyl groups, e.g. ethylene glycol, 1,2 - propane diol, 1,3 - propane diol, hexamethylene diol, trimethylol propane, glycerol, trihydroxy hexane, 1,2 - dihydroxy cyclohexane or 1,4 - dihydroxy cyclohexane. Low molecular weight polyols containing ether groups, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol or tetrapropylene glycol, are also suitable.

In principle, various mixtures of the above-mentioned polyhydroxyl compounds may be used, provided the individual components are compatible with each other.

The lacquers produced with the aid of the present diisocyanates or the corresponding blocked diisocyanates are mainly distinguished by the fact that they may be processed without solvents to produce light-fast coatings which are free from bubbles and have excellent mechanical properties.

It is generally not necessary to use a water-absorbing or a dehydrating agent when preparing the lacquer mixtures. The lacquers according to the present invention may be combined with pigments and fillers in the conventional apparatus employed in the lacquer industry.

Other lacquer raw materials and/or auxilliary agents, such as cellulose esters, levelling agents, plasticizers, silicone oils and resins, may, of course, also be added.

Known catalysts may be added to adjust the reactivity of the polyurethane lacquers. The lacquers may be applied to the substrates by the conventional methods, such as brush coating, spraying or dip coating. They are in particular suitable for coating substrates, made of wood, metal or plastics.

The present diisocyanates are not only valuable intermediate products for the production of polyurethanes, but may also be used as aqueous dispersions without further chemical modification to serve as paper sizes. These aqueous dispersions may be prepared simply by mixing the present diisocyanates with suitable emulsifiers, preferably non-ionic emulsifiers, e.g.

iso-C9H1 9-C6H4-O-CH2-CH2-) 10-O-CH2-CH2-C=-N and then stirring this mixture in water to form the ready-made dispersion, preferably shortly before use. The emulsifiers are generally used in quantities of from 2 to 20 parts, by weight, preferably about 10 parts, by weight, per 100 parts, by weight, of the present diisocyanate. The quantity of water used for preparing the dispersion ready for use as paper size is generally calculated to produce a from 0.01 to 2%, by weight, aqueous dispersion. This dispersion is particularly suitable for pulp sizing paper.

Example 1 9,10 - diisocyanato - 1,4:5.8 - dimethano - tetradecahydroanthracene (XIII): Stage A 300 g of 1,4:5,8 - dimethanol,4,4a,5,8a,9a,10a - octahydroanthraquinone (1,25 mol) were hydrogenated for 4 hours at from 140 to 1500C and a hydrogen pressure of from 120 to 150 bar in 1000 ml of methanol in the presence of 15 g of Raney cobalt catalyst, 360 g of liquid ammonia and 7g of glacial acetic acid. The catalyst was then removed and the reaction product distilled after evaporation of excess solvent. The diamine (III) boiled at from 157 to 1590C/0.1 Torr and was obtained as colourless, viscous liquid in a yield of 280 g (91%).

nD5: 1.5613 Analysis: (here and in all subsequent Examples in /", by weight) Observed: C 78.2 H 10.78 N 11.42 Calculated: C 78.1 H 10.57 N 11.38 Stage B 100 g of 9,10 - diamino - 1,4:5,8 - dimethano - tetradecahydroanthracene (0.41 mol) in 500 ml of chlorobenzene were added dropwise to a solution of 200 g of phosgene and 500 ml of chlorobenzene at --200C. The reaction mixture was then slowly heated with continued supply of phosgene so that the temperature rose from -200C to 500C within the first hour and then from 80"C to 1200C within the next 1+ hours. The reaction solution was concentrated by evaporation and the isocyanate XIII was distilled in a high vacuum. A yellowish white, crystalline product boiling at 16"C/0.15 Torr was obtained in a yield of 113 g (93 /,). M.p. 9--92"C.

Observed: C 72.64 H 7.22 N 9.39 0 10.03 Calculated: C 72.48 H 7.38 N 9.39 0 10.74 Example 2 9,10 - diisocyanato - 2,6(or -2,7)- dimethyl - tetradecahydroanthracene (XVII) Stage A 300 g of 2,5(or 2,7) - dimethyl - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (1.23 mol) were dissolved in 1200 ml of dioxane and hydrogenated for 3 hours at a hydrogen pressure of from 120 to 150 bar and a temperature of 1500 in the presence of 360 g of liquid ammonia, 7 g of glacial acetic acid and 15 g of Raney cobalt catalyst. After removal of the catalyst, the reaction mixture was processed by distillation. The diamine (VII) boiled at from 14i to 1440C/0.88 Torr and was obtained in a yield of 292 g (95 ,;).

nod5: 1.5514 Analysis: Observed: C 76.2 H 12.11 N 11.15 Calculated C 76.8 H 12.0 N 11.20 Stage B 200 g (0.8 mol) of 9,10- diamino - 2,6(or -2,7)- dimethyl tetradecahydroanthracene (VII) obtained in Stage A were introduced into 1.5 1 of chlorobenzene in a 5 litre three-necked flask and carbon dioxide was added to the reaction mixture containing boiling solvent until the reaction had been completed.

The mixture was then cooled to -50C for phosgenation. The carbamate was thereby precipitated. About 180 g (1.8 mol) of phosgene were condensed in the cold suspension. Phosgene continued to be added while the reaction mixture was slowly heated until the solvent boiled. Phosgenation was continued until a clear solution was obtained. This solution was freed from excess phosgene by scrubbing with nitrogen and then concentrated by evaporation under vacuum. 9,10 diisocyanato - 2,6(or -2,7) - dimethyl - tetradecahydroanthracene was isolated from the crude product by extraction with petroleum ether or by high vacuum distillation (B.p.=1520C/0.33 Torr).

Yield: 15i g (65%).

Analysis: Observed: C 71.0 H 8.2 N 9.5 0 11.3 Calculated: C 71.0 H 8.61 N 9.27 0 10.59 Example 3 9,10 - diisocyanato - 1,4 - methano - tetradecahydroanthracene (XIV) Stage A 250 g of 1,4 - methano - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (1.1 mol) in 1000 ml of methanol were hydrogenated for 3 hours at 1500C and from 120 to 150 bar hydrogen pressure in the presence of 300 g of liquid ammonia, 8g of acetic acid and 12 g of Raney cobalt catalyst.

After removal of the catalyst and evaporation of the solvent, the residue was distilled in a high vacuum. The diamine (IV) boiled at from 137 to 1390C/0.08 Torr and was obtained in a yield of 200 g (78%).

nod5: 1.5556 Analysis: Observed: C 76.40 H 12.0 N 12.05 Calculated C 76.92 H 11.11 N 11.96 Stage B The diamine (IV) obtained in Stage A was phosgenated as described in Example 1 (Stage B). 200 g (0.85 mol) of the diamine yielded 175 g (72%) of 9,10 diisocyanato - 1,4 - methano - tetradecahydroanthracene boiling at from 153 to 156"C/0.2 Torr. M.p. 340C.

Analysis: Observed: C 71.3 H 7.6 N 9.8 0 12.0 Calculated: C 71.32 H 7.69 N 9.79 0 11.18 Example 4 9,10 - diisocyanato - 1,4 - methano - 6 - methyl - tetradecahydroanthracene (XV) Stage A 300 g of 6- methyl - 1,4 - methano - 1,4,4a,5,8,8a,9a,10a - octahydroanthraquinone (1.24 mol) hydrogenated in 1000 ml of methanol in the presence of 480 g of liquid ammonia, 8 g of glacial acetic acid and 15 g of Raney cobalt catalyst yielded 274 g (89%) of diamine. Hydrogenation was carried out for 3 hours at from 120 to 150 bar hydrogen pressure and 1500C. The diamine (V) was isolated from the crude product by high vacuum distillation at 1370C and 0.1 Torr.

nD5: 1.5584.

Analysis: Observed: C 77.0 H 12.10 N 11.34 Calculated: C 77.42 H 11.29 N 11.29 Stage B 125 g of the diamine (V) were phosgenated as described in Example 1. The diisocyanate (XV) boiling at 1550C/0.15 Torr was isolated as a slightly yellowish liquid from the crude product by high vacuum distillation. Yield 128 g (85%) Analysis: Observed: C 72.0 H 8.4 N 9.1 0 11.0 Calculated: C 72.0 H 8.0 N 9.3 0 10.6 Example 5 The properties of a commercial air drying alkyd resin lacquer used for respraying car bodies were compared with the properties of a laqcuer which, in addition, contained a diisocyanate according to the present invention and was otherwise the same.

The alkyd resin contained 48% of drying vegetable fatty acids and 26% of the phthalic acid anhydride. It was dissolved as a 55% solution in a mixture of turpentine substitute and xylene (proportions 38:7). A lacquer suitable for car bodies was prepared by the addition of various auxiliary agents and additives. This lacquer had the following composition: Parts by weight Alkyl resin (55% in petroleum hydrocarbons/xylene 38:7) 236.6 Titanium dioxide (TiO2 rutile as pigment) 84.5 Zinc octoate (8% metal) liquid 0.8 Alkyl aromatic mixture (xylene alkyl benzenes; boiling range 150 to 1800C) 26.0 Ethyl glycol acetate 3.9 Anti-skinning agent (butanone oxime) 1.9 Co-octoate (8 /n metal) 1.3 Pb-octoate (24% metal) 5.4 To this alkyl resin lacquer were added 10% by weight, and 20%, by weight, (solid to solid) of the isocyanate according to the present invention ob lacquer, its firmness of adherence to the substrate and its solvent resistance. The pot life was slightly shortened. This meant that a lacquer containing the isocyanates according to the present invention had to be used at the latest after from 2 to 5 days, while the unmodified alkyd resin lacquer could still be applied after 10 days.

Some of the properties are shown in the following Table: Alkyd resin lacquer containing 10% 20% pure alkyd Addition Addition resin of polyisocyanates from lacquer Example 1 Example 2 Knig's pendulum hardness (after 16 hours at 250C) 20 sec. 42 sec. 56 sec.

Resistance to high octane surface no no petrol after 7 days severely marks marks (20' exposure, 30' marked regeneration) Resistance to adhesive pronounced very no after 16 hours' drying marking on slight marking at 25"C (adhesive tape the lacquer marking is removed after 15 surface of the min. results assessed after lacquer 30 min) surface U.K. Patent No. 1560453 (application No. 35918/77) discloses and claims a compound corresponding to the following general formula (Ia):

wherein n and m which may be the same or different each represents 0, 1 or 2; R, R, and R2 which may be the same or different each represents hydrogen or methyl; and either (a) R3 and R5 each represents hydrogen; and R4 and R8 each independently represents hydrogen C1-C18 alkyl which may be interrupted by oxygen and/or may be hydroxy-substituted or C3-C8 cycloalkyl; or (b) R3, R4, R5 and R6 each independently represents C,C,8 alkyl which may be interrupted by oxygen and/or may be hydroxy-substituted or C5-C8 cycloalkyl or (c) R3 and R4 together and R5 and R6 together complete with the nitrogen atom to which they are attached a C4-C6 heterocyclic ring which may be interrupted by oxygen and/or nitrogen and which may be C1-C4 alkyl and/or hydroxy C1-C4 alkyl-substituted provided that, if n and m each represents 0, then at least one of R and R, represents other than hydrogen.

WHAT WE CLAIM IS: 1. A diisocyanate corresponding to the following general formula:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

lacquer, its firmness of adherence to the substrate and its solvent resistance. The pot life was slightly shortened. This meant that a lacquer containing the isocyanates according to the present invention had to be used at the latest after from 2 to 5 days, while the unmodified alkyd resin lacquer could still be applied after 10 days.

Some of the properties are shown in the following Table: Alkyd resin lacquer containing 10% 20% pure alkyd Addition Addition resin of polyisocyanates from lacquer Example 1 Example 2 Knig's pendulum hardness (after 16 hours at 250C) 20 sec. 42 sec. 56 sec.

Resistance to high octane surface no no petrol after 7 days severely marks marks (20' exposure, 30' marked regeneration) Resistance to adhesive pronounced very no after 16 hours' drying marking on slight marking at 25"C (adhesive tape the lacquer marking is removed after 15 surface of the min. results assessed after lacquer

30 min) surface U.K. Patent No. 1560453 (application No. 35918/77) discloses and claims a compound corresponding to the following general formula (Ia):

wherein n and m which may be the same or different each represents 0, 1 or 2; R, R, and R2 which may be the same or different each represents hydrogen or methyl; and either (a) R3 and R5 each represents hydrogen; and R4 and R8 each independently represents hydrogen C1-C18 alkyl which may be interrupted by oxygen and/or may be hydroxy-substituted or C3-C8 cycloalkyl; or (b) R3, R4, R5 and R6 each independently represents C,C,8 alkyl which may be interrupted by oxygen and/or may be hydroxy-substituted or C5-C8 cycloalkyl or (c) R3 and R4 together and R5 and R6 together complete with the nitrogen atom to which they are attached a C4-C6 heterocyclic ring which may be interrupted by oxygen and/or nitrogen and which may be C1-C4 alkyl and/or hydroxy C1-C4 alkyl-substituted provided that, if n and m each represents 0, then at least one of R and R, represents other than hydrogen.

WHAT WE CLAIM IS: 1. A diisocyanate corresponding to the following general formula:

wherein n and m which may be the same or different, each represents 0, 1 or 2; and R, R1 and R2 which may be the same or different each represents hydrogen or methyl; provided that, when n and m each represents 0, then at least one of R, Rl, and R2, represents other than hydrogen.
2. A diisocyanate as claimed in Claim 1 wherein n and/or m represents 0 or 1.
3. A diisocyanate as claimed in Claim I or Claim 2 wherein R, represents hydrogen in the alkylene bridge (C, R, R,).
4. A diisocyanate as claimed in Claim 1 which is a compound corresponding to one of the formulae (XIII) to (XVII) listed hereinbefore.
5. A diisocyanate as claimed in Claim 1 substantially as herein described.
6. A diisocyanate as claimed in Claim 1 substantially as herein described with reference to any one of the Examples.
7. A process for the preparation of a diisocyanate as claimed in Claim 1 which comprises phosgenating the corresponding diamine.
8. A process as claimed in Claim 7 in which the phosgenation is carried out by introducing the amine into a solution of phosgene at a temperature of from -20 to +5"C and heating the reaction mixture slowly until a clear solution is obtained.
9. A process as claimed in Claim 8 in which the phosgenation is carried out in solution in a halogenated alkane or cycloalkane or a halogenated aromatic compound.
10. A process as claimed in Claim 9 in which the solvent is chlorobenzene or o- dichlorobenzene.
11. A process as claimed in any of Claims 7 to 10 in which the diamine is a compound corresponding to one of the formulae (III) to (VII) as listed hereinbefore.
12. A process as claimed in Claim 7 substantially as herein described.
13. A process as claimed in Claim 7 substantially as herein described with reference to any one of the Examples.
14. A process as claimed in any of Claims 7 to 13 in which the diamine corresponding to the general formula (I):

wherein n, m, R, R, and R2 are as defined in Claim 1, which is to be subjected to a phosgenation reaction, has been obtained by hydrogenation of a compound corresponding to the following general formula (II):

or to the following general formula (IIa):

wherein n, m, R, R, and R2 are as defined in Claim 1; hydrogenation being accompanied by reductive amination of the CO groups and addition of hydrogen to the C=C double bonds.
15. A process as claimed in Claim 14 in which hydrogenation is carried out in the presence of from 2 to 30 mol of ammonia per mol of (II).
16. A process as claimed in Claim 15 in which the hydrogenation is carried out in the presence of from 3 to 15 mol of ammonia per mol of (11).
17. A process as claimed in any of Claims 14 to 16 in which the hydrogenation is carried out at a temperature of from 30 to 1800C and a hydrogen pressure of from 5 to 200 bar.
18. A process as claimed in Claim 17 in which the hydrogenation is carried out at a temperature of from 60 to 1500C and a hydrogen pressure of from 30 to 150 bar.
19. A process as claimed in any of Claims 14 to 18 in which the hydrogenation is carried out in the presence of a catalyst containing an element of Group VIII in the metallic or oxidised form.
20. A process as claimed in any of Claims 14 to 19 in which the compound (II) or (IIa) is a compound corresponding to one of the formulae (VIII) to (XII) listed hereinbefore.
21. A process as claimed in Claim 14 substantially as herein described.
22. A process as claimed in Claim 14 substantially as herein described with reference to any one of the Examples.
23. A diisocyanate as claimed in Claim 1 when prepared by a process as claimed in any of Claims 7 to 22.
24. A process for the production of a polyurethane or polyurethane urea which comprises subjecting a diisocyanate as claimed in any of Claims 1 to 6 or Claim 23 to the polyisocyanate polyaddition process.
25. A process as claimed in Claim 24 substantially as herein described.
26. A process as claimed in Claim 24 substantially as herein described with reference to any one of the Examples.
27. A polyurethane or polyurethane urea when produced by a process as claimed in any of Claims 24 to 26.
28. A polyurethane or polyurethane urea as claimed in Claim 27 which is in the form of a lacquer.
29. A method of sizing paper which comprises applying to the paper an aqueous dispersion of a diisocyanate as claimed in any of Claims 1 to 6 or Claim 23.
30. A method as claimed in Claim 29 in which the aqueous dispersion contains a non-ionic emulsifier.
31. A method as claimed in Claim 30 in which the non-ionic emulsifier is iso-C9H 19-C6H4-(-O-CH2-CH2-) 10-O-CH2CHrnC=N.
32. A method as claimed in any of Claims 29 to 31 in which the dispersion contains the emulsifier in a quantity of from 2 to 20 parts, by weight, per 100 parts, by weight, of diisocyanate.
33. A method as claimed in Claim 32 in which the emulsifier is present in a concentration of 10 parts, by weight, per 100 parts, by weight, of diisocyanate.
34. A method as claimed in any of Claims 29 to 33 in which the dispersion is from 0.01 to 2% by weight aqueous dispersion.
35. A method as claimed in Claim 29 substantially as herein described.
36. Paper when sized by a method as claimed in any of Claims 29 to 35.