CA2065191A1 - Process for the preparation of aromatic amines and the use of the amines so produced - Google Patents

Abstract

Mo-3598 PROCESS FOR THE PREPARATION OF AROMATIC AMINES
AND THE USE OF THE AMINES SO PRODUCED
ABSTRACT OF THE DISCLOSURE
The present invention is directed to a process of producing an aromatic amine by reacting a n-chloroformate with an aromatic diamine. The resultant diamines are characterized by relatively low viscosities and are emminently suitable for use in the RIM process.

Description

Mo-3598 206~191 PROCESS FOR THE PREPARATION OF AROMATIC AMINES
AND THE USE OF THE AMINES SO PRODUCED
BACKGROUND OF THE INVENTION
Polyadducts containing aromatic amino end groups are s known. U.S. Patents 2,888,439 and 3,385,829 describe the preparation of amino polyethers by the reaction of nitro-arylisocyanates with polyols followed by hydrogenation. The analogous reaction of azoaryl isocyanates with polyols also yields aromatic aminopolyethers after reduction (U.S. Patent o 3,474,126).
A process in which isocyanate prepolymers are reacted w;th diamines conta;ning different reactive amino groups is described in German Offenlegungsschriften 1,122,254 and 1,694,152. The reaction of isocyanate prepolymers with sulphamic acid accord;ng to German Auslegeschrift 1,155,907, with formic acid according to French Patent 1,415,317 or with enamines, aldimines or ketimines contain;ng hydroxyl groups according to German Offenlegungsschriften 2,116,882 and 2,546,536 results in aromatic amino polyethers after hydrolysis and saponification as does the thermal splitting of urethanes from isocyanate prepolymers and secondary or tertiary carbonals according to German Auslegeschrift 1,270,046. German Offen-legungsschriften 2,948,419, 3~223,397, 3,223,398 and 3,223,400 describe various single stage and two-stage processes for the preparation of aromatic polyamines by the hydrolysis of isocyanate prepolymers in the presence of various solvent and catalyst systems.
All the processes described give undesirably high viscosity products which are not suited for many purposes.

206~191 Reaction injection molded (RIM) polyurethanes are well known in the art and have met with substantial commercial success. U.S. Patent 4,218,543 describes the use of relatively high molecular weight hydroxyl group containing materials, aromatic diamines as chain extenders, and isocyanates for the production of RIM parts.
More recently, the activity in the art has been towards the production of polyurea RIM parts. Typically, these parts are made from relatively high molecular weight polyethers o which contain amine groups, diamine chain extenders, and isocyanates. Typical of the materials used and the technologies known in the art are those described in U.S.
Patents 4,396,729, 4,433,067, 4,444,910, 4,53~,941, 4,774,263 and 4,774,264. As is known in the art, RIM parts are generally produced from two separate streams. One stream generally contains the lsocyanate component, while the other stream contains the amine containing polyether and the amine chain extender. Am;ne containing polyethers where the amine groups are attached to aromatic groups are generally too viscous for use in conventional RIM machinery, while amine-containing polyethers where the amine groups are attached to aliphatic moieties are too reactive to be used alone with conventional aromatic isocyanates. One object of the present invention was to provide a mixture of amine-containing reactant and amine chain extender having a substantially reduced viscosity and thus improved flow characteristics. Additionally, this improvement in flow properties would have to be achieved without adversely affecting the physical properties of the final RIM part.
Compounds having terminal aromatic amine groups and having the general structure:

Mo-3598 s ~ ~1"k are known. In U.S. Patent 3,808,250, X is defined as oxygen or sulfur, n is an integer of from 2 to 8, and R is defined as an n-valent radical obtained by the removal of hydroxy or mercapto groups from an n-valent polyether or polythioether having a molecular weight of from 600 to 10000. U.S. Patents 3,817,940 15and 3,929,863 descr;be similar compounds where R is based on a polyol or polythiol having a molecular weight of less than 600.
U.S. Patents 3,975,428 and 4,016,143 describe similar compounds prepared by reacting isatoic acid anhydride with a compound containing at least two hydroxyl groups and at least one 20 tertiary nitrogen group and having a molecular weight of from about 119 to about 1000. Similar compounds are described in U.S. Patents 4,136,091, 4,169,206, 4,186,257, 4,228,249 and 4t260,557. Para-substituted compounds are described in U.SO
Patents 4,504,648 and 4,515,981. Finallya similar para-, meta-25 and di-meta- substituted compounds are described in U.S.
Patents 4,328,322 and 4,732,959. While all of these references describe that the compounds disclosed can be used to manufacture polyurethane products, none describe the use in a polyurea RIM process.
30Recently, there have been disclosed poly(amino-aromatic~ compounds of the formula:

35 ~ X R

2)y n Mo-3598 4 206~191 where R is the residue after removal of hydroxyl groups or mercapto groups from a polyol or polythiol of molecular weight of from 400 to 12,000, n ;s from 2 to 8, X represents oxygen or sulfur, A is hydrogen or an inert substituent, and y is 1 or 2.
See European Patent Application 0,268,849 and U.S. Application Serial Number 183,556, filed on April 19, 1988.
The reaction of diamines with bischloroformates formed from phosgene and polyols is known. See, e.g., U.S.
Patents 2,888,439, 2,929,802, 2,835,654, 3,254,056, and o 3,385,833. The products described in these patents are solid elastomers.
It was an object of the present invention to provide new aromatic polyamines which would not have the disadvantages mentioned above and would in particular have lower viscosities 15 and react more advantageously with isocyanates. ~his problem was solved by the process described be10w.
DESCRIP~ION OF THE INVENTION
The present inYention is directed to a novel process for preparing aromatic amines and to the use of such amines in 20 a reaction injection molding ("RIM") process. The viscosities of the resultant amines are preferably 20,000 mPa.s or less at 25-C and substantially lower than those obtainable from the processes of the prior art. More particularly, the present invention is directed to a process for the preparation of an 25 aromatic amine comprising reacting (a) an n-chloroformate of an n-hydroxyl functional material, said n-hydroxyl functional material having a molecular weight of from about 200 to about 12,000, and preferably from about 500 to about 6000, and wherein n is an 30 integer of from 2 to 6, preferably from 2 to 3, with (b) an aromatic diamine having a molecular weight of from 106 to 400, preferbaly in a ratio of 2 or more moles of aromatic diamine per chloroformate equivalent. A
~chloroformate equivalent~ is defined as the molecular weight of the n-chloroformate divided by n.

Mo-3598 The process of the invention broadly involves the reaction of an aromatic diamine, which can be primary or secondary, with a chloroformate prepared by reacting a hydroxy functional material with phosgene. The reaction of the diamine and the chloroformate is generally conducted in the presence of a solvent. Useful solvents include toluene and tetrahydro-furan, although any solvent can be used so long as both reactants are completely soluble therein and so long as the solvent does not react with either reactant. The process preferably involves the addition of the n-chloroformate, which may or may not be dissolved in a solvent, to the well stirred diamine which is dissolved in solvent. The temperature of reaction can be anywhere from as low as 0C to as high as the boiling point of the solvent. Preferably, the reaction temperature is kept at about 25C. The reaction is complete once the chloroformate addition is complete. In general, the amine hydrochl~ride salt that is formed by the reaction can be removed by filtration or by reaction with sodium hydroxide, or any other suitable base, and the solvent is distilled off. The resultant aromatic amine is filtered to remove the salt (e.g., sodium chloride, if sodium hydroxide is used as the base). Any excess aromatic diamine can either be removed, for example, by distillation or thin film evaporation, or it can be left in the amine, in which case it will function as a chain extender in the subsequent use in a RIM process. The major improvement in the present invention resides in the lower viscosities obtainable.
It is preferred to use from 100 to 500 parts by weight of solvent per 100 parts by weight of starting diamine.
Of course, the amount used could be more or less depending upon the viscosity of the reaction mixture. The amine hydrochloride formed from the diamine and the liberated hydrogen chloride precipitates out of solution causing the viscosity to rise.
The increase in viscosity depends upon which diamine is used.
If the viscosity is too high, poor mixing occurs which in turn Mo-3598 206~191 leads to the formation of high molecular weight (i.e., chain extension) due to localized under indexing. This high molecular weight material leads to products with high viscosity.
The amines herein are prepared by reacting an n-chloroformate formed from an n-valent polyhydroxyl compound and phosgene with aromat;c diamine.
The polyhydroxyl compounds used to produce the n-chloroformate are compounds having an average molecular weight of about 200 to about 12,000, and preferably from about 500 to about 6000, and containin~ from 2 to 6, preferably 2 to 3 reactive hydroxyl groups. Suitable examples include the hydroxyl group-containing compounds conventionally used in polyurethane chemistry such as hydroxyl-containing polyacetals, polythioethers, polycarbonates, polyamides, polysiloxanes and~or polybutadienes, polyesters, polyacetones and polyethers.
Among these, polyethers containing hydroxyl groups are particularly preferred.
The hydroxyl polyethers useful herein are known and may be prepared, for example, by the polymeri7ation of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetra-hydrofuran, styrene oxide or epichlorohydrin on their own, e.g.
in the presence of BF3, or by chemical addition of these epoxides, optionally as mixtures or successively, to starting 25 components containing reactive hydrogen atoms such as water, alcohols or am;nes. Examples include ethylene glycol, propylene glycol-(1,3) or -(1,2), trimethylol propane 4,4'-dihydroxydiphenyl propane, glycerine, sorbitol, pentaerythritol, aniline, ammonia, ethanolamine, ethylene 30 diamine and the like. Polyethers modified by vinyl polymers of the kind obtained, for example, by the polymerization of styrene and acrylonitrile in the presence of polyethers (U.S.
Patents 3,383,351, 3,304,273, 3,523,093 and 3,110,695 and German Patent 1,152,536) are also suitable, as are poly-35 butadienes containing OH groups.
Mo-3598 206~191 Suitable polyacetals include the compounds obtained from formaldehyde and glycols such as di- or tr;-ethylene glycol, 4,4'-dioxethoxy-d;phenyl-dimethyl-methane (bisphenol A
+ 2 mol ethylene oxide) and hexane diol or by the polymeri-zation of cyclic acetals, such as trioxane.
Suitable polycarbonates containing hydroxyl groups are known and include those prepared by the reaction of diols such as propane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, di-, tri- or tetraethylene glycol or thiodiglycol with phosgene o or diarylcarbonates.
The polyesters of dicarboxylic acids and diols may be those obtained from adipic acid and isophthalic acid and straight chained and/or branched diols as well as lactone polyesters, preferably those based on caprolactone and starter diols.
Particularly important among the polythioethers are the condensation products obtained by react;ng th;odiglycol on its own and/or with other glycols.
Polyhydroxyl compounds already containing urethane or urea groups and modified or unmodified natural polyols may also be used. Products of addition of alkylene oxides to phenol-formaldehyde resins or to ureaformaldehyde resins may also be used according to the ;nvent;on. Furthermore, am;de groups may be introduced ;nto the polyhydroxyl compounds as described e.g., ;n German Auslegeschrf;t 2,559,372.
Polyhydroxyl compounds ;n wh;ch h;gh molecular we;ght polyadducts or polycondensates or polymers are present in a finely dispersed or dissolved form may also be used according to the invention. Polyhydroxyl compounds of this type may be obta;ned, for example, by carry;ng out polyaddit;on reactions (e.g. reactions between poly;socyanates and am;no functional compounds) or polycondensation reactions (e.g. bet~een formaldehyde and phenols and/or amines) in situ in the above mentioned co~pounds conta;ning hydroxyl groups. Processes o~
this type are descr;bed, for example, in German Patents Mo-3598 206~191 1,1~8,075 and 1,260,142 and German Auslegeschriften 2,324,134, 2,423,984, 2,512,385, 2,513,~15, 2,550,796, 2,550,797, 2,550,833, 2,550,862, 2,633,293 and 2,639,254. The required compounds may also be obtained according to U.S. Patents 3,869,413 or 2,550,860 by mixing a previously prepared aqueous polymer dispersion with a polyhydroxyl compound and then removing water from the mixture.
Polyhydroxyl compounds modified with vinyl polymers such as those obtained, for example, by the polymerization of styrene and acrylonitrile in the presence of polycarbonate polyols (~erman patent 1,769,795, U.S. Patent 3,637,g09) are also suitable for the process according to the invention.
Synthetic resins with exceptional flame resistance may be obtained by using polyether polyols which have been modified by graft polymerization with vinyl phosphonic acid esters and optionally (meth)acrylonitrile, (meth)acrylamide or OH-functional (meth)acrylic acid esters according to German Auslegungschriftten 2,442,101, 2,644,922 and 2,646,141.
When modified polyhydroxyl compounds of the type mentioned above are used as starting materials for the chloroformates, the resulting starting components used in the polyisocyanate polyaddition processes in many cases result in polyurethanes which have substantially improved mechanical properties.
Suitable, although less preferred, polyhydroxyl components also include the organofunctional polysiloxanes containing two terminal isocyanate-reactive groups and structural units of the formula -O-Si(R)2 in which R denotes a Cl-C4 alkyl group or a phenyl group, preferably a methyl group.
Both the known, pure polysiloxanes containing organofunctional end groups and the known siloxane polyoxyalkylene copolymers containing organofunctional end groups are suitable starting materials according to the invention. Preferred organo-polysiloxanes correspond to the general formula Mo-3598 206~

IH3 ~ IH3 ~

s HO-CH2- Si ~ O---Si CH2 OH
I
CH3 CH3 n o where n = 5 to 29. These materials are prepared ;n known manner by the equilibration of 1,1,3,3-tetramethyl-1,3-hydroxymethyl d;siloxane of the formula HO-CH2- Si 0- Si CH2 - OH
l l with octamethylene cyclotetrasiloxane in the presence of sulfuric acid or by the process according to German Patent 1,236,505.
The n-chloroformates are prepared in known manner by 20 reaction of the polyhydroxyl compound with phosgene. Gaseous or liquid phosgene can be added to the polyhydroxyl compound at temperatures between O and 40-C. The use of a reflux condenser cooled to less than OCC is also desirable. Alternatively, the polyhydroxyl compound can be added to liquid phosgene. In both 25 cases, solvents can be used to dissolve the polyhydroxyl compound, the phosgene or both so long as the solvent does not react with the starting materials or the resulting chloro-formate. Useful solvents have boiling points of less than 150-C at 760 mm Hg and include tetrahydrofuran, toluene, carbon 30 tetrachloride and the like. The reaction time will vary from 1 hour to 12 hours depending upon the reaction temperature and the polyhydroxyl compound used. The work-up involves removal Mo-3598 -lo-of the excess phosgene and hydrogen chloride by purg;ng with dry nitrogen and/or placing the system under vacuum. In the case where solvents are used, they are removed by distillation and, where the boil;ng point of the solvent is above 50-C, they are removed by vacuum distillation. It is desirable not to s allow the chloroformates to reach a temperature above 60~C.
Purging with dry nitrogen to remove solvent is also possible.
The n-chloroformates are reacted with aromatic diamines. The aromatic d;amines useful in the process of the present invention generally have molecular weights of from 108 to 400 and preferably contain exclusively aromatically bound primary or secondary (preferably primzry) amino groups.
Examples of such diamines are: 1,4-diaminobenzene, 2,4-diaminotoluene, 2,4- and/or 4,4'-diaminodiphenyl methane, 3,3'-dimethyl-4,4'-diaminodiphenyl methane, 4,4'-diamino^
diphenylpropane-(2,2), mixtures of such diamines, and the like.
Preferred diamines have alkyl substituents in at least one position which is ortho to the amino groups. ~he most preferred diamines are those in which at least one alkyl substituent is present in the position ortho to the first amino group and two alkyl substituents are located in the position ortho to the second amino group, each alkyl substituent having 1 to 4 carbon atoms. It is particularly preferred to use such compounds in which an ethyl, n-propyl, isopropyl, t-butyl and/or methylthio substituent is present in at least one position ortho to the amino groups and possibly methyl substituents in other positions ortho to the amino groups.
Specific examples of preferred amines include 2,4-diaminomesitylene, 1,3,5-triethyl-2,4-diamino-benzene, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 4,6-dimethyl-2-ethyl-1,3-diaminobenzene, 3,5,3',5'-tetraethyl-4,4'-diaminodiphenyl methane, 3,5,3'5'-tetraisopropyl-4,4'-diaminodiphenyl methane, 3,5-diethyl-3,5'-di-isopropyl-4,4-diaminodiphenyl methane, t-butyl toluene diamine and bis-Mo-3598 thiomethyl toluene diam;ne. Also useful are adducts of these aminos with epoxy resins.
The process is carried out in the presence of an organic solvent. The components for the reaction, i.e., the n-chloroformate and the diamine may be present in a homogeneous phase or diphasic, i.e., as solutions, emulsions or suspensions.
Examples of suitable organic solvents include benzene, toluene, xylene, chlorobenzene, dichlorobenzene, o trichlorobenzene, diethylether, diisopropylether, tert.-butylmethylether, tetrahydrofuran, dioxane, ethylene glycol dimethylether, ethyl acetate, acetonitrile, methylene chloride, chloroform, trichloroethylene, tetrachloroethylene, nitromethane and nitropropane. Polar aprotic solvents which can be used include dimethylformamide, dimethylacetamide, N-methylpyrrolidone, tetramethyl urea. N-methylcaprolactam, dimethyl sulfoxide, tetramethylene sulphone, hexamethylene phosphoric acid triamide, and the like. Tertiary amine solvents, such as pyridine and triethylamine can also be used.
They have the advantage of reducing the amount of diamine needed for a specific product since these solvents absorb free hydrogen chloride generated during the reaction (for example, as little as one mole of aromatic diamine can be used per chloroformate equivalent). Toluene and THF are presently preferred. Mixtures of such solvents may, of course, also be used.
The quantity of solvent used is generally calculated to be that amount which is sufficient if it forms a clear solution of the starting diamine. In practice, this means that the solvents are generally used in a quantity of about 50 to 1,000, preferably about 100 to 500 parts by weight of solvent per 100 parts by weight of the starting diamine.
Following the completion of the reaction, the amine hydrochloride salt can be removed by filtration or neutralized using a base. Examples of compounds which are alkaline in Mo-3598 206~191 reaction as required for the neutralization include metal hydrides, metal alkoxides and, preferably, metal hydroxides.
Sodium hydroxide and potassium hydrox;de are part;cularly preferred.
The resultant aromat;c amine materials are worked up in known manner, suitably by dist111ing off the solvent (optionally under vacuum) and dry;ng the product under vacuum.
The crude product obtained may generally be used without further purification but if it is des;red to remove all of the unreacted diamine, this may be removed by th;n layer d;st;l-o lat;on. Alternatively, the unreacted diamine can be left ;n the product and w;ll act as a chain extender when used ;n a RIM
process.
The polyamines obta;ned from work;ng up the reaction mixture are distinguished from prev;ously known aromat;c aminopolyethers by their substant;ally lower v;scos;ty. Apart from the various groups already present ;n the polyhydroxyl compounds from which they have been obta;ned, e.g. ether groups, thioether groups, d;alkyl siloxane, carbonate groups and/or polybutad;ene groups, they conta;n urethane groups correspond;ng ;n number to their functionality.
The amines here;n are useful in the RIM process. As ;s known ;n the art, the RIM process broadly ;nvolves the react;on of an isocyanate with one or more act;ve hydrogen conta;ning materials ;n a closed mold us;ng h;gh pressure mixing equipment.
The isocyanate used in the RIM process of the present ;nvent;on is preferably an aromatic diisocyanate and/or poly;socyanate, i.e., a polyisocyanate ;n which all of the isocyanate groups are aromat;cally bound. Examples of such compounds include 2,4- and/or 2,6-diisocyanatotoluene; 2,2'-, 2,4'- and/or 4,4'-diisocyanatodiphenyl methane, m;xtures of the last ment;oned ;somers w;th their h;gher homologues (such as are obta;ned from the known reaction of the phosgenat;on of anil;ne/formaldehyde condensates); compounds conta;n;ng Mo-3598 urethane groups obtained as products of reaction of the above-mentioned di- and/or polyisocyanates w;th subequivalent quantities of polyhydroxyl compounds having molecular weights of from 62 to 10,000, (e.g., ethylene glycol, trimethylol propane, propylene glycol, dipropylene glycol or polypropylene glycols, and polyester glycols within the above-mentioned molecular weight range); di- and/or polyisocyanates modified by the partial carbodiimidization of the isocyanate groups of the above-mentioned di- and/or polyisocyanates; methyl-subst;tuted diisocyanates of the diphenyl methane series or mixtures thereof (for example, those described in European application No. 0,024,665); or mixtures of such aromatic di- and polyisG-cyanates.
Included among the preferred isocyanates are the derivatives of 4,4'-diisocyanatodiphenyl methane which are liquid at room temperature. Spec;fic examples of such compounds are polyisocyanates containing urethane groups obtainable according to German Patent 1,618,380 (U.S. Patent 3,644,457) by reacting 1 mol of 4,4'-diisocyanato-diphenyl methane with from 0.05-0.3 mol of lo~ molecular weight diols or triols, (preferably polypropylene glycols having molecular weights below 700) diisocyanates based on 4,4'-diisocyanato-diphenyl methane containing carbodiimide and/or uretoneimine groups, such as those disclosed in U.S. Patents 3,152,162;
3,384,653 and 3,449,256, German Offenlegungsschrift No.
2,537,685 and European Application No. 5233. Also i~cluded among the preferred polyisocyanates are the corresponding modified products based on mixtures of 2,4'- and 4,4'-diiso-cyanatodiphenyl methane or mixtures of the above-described modified 4,~'-diisocyanatodiphenylmethanes with minor quantities of higher than difunctional polyisocyanates of the diphenyl methane series. Such polyisocyanates are described in German Offenlegungsschrift 2,624,526. The preferred polyisocyanate mixtures of the diphenyl methane series are liquid at room temperature and have optionally been chemically Mo-3598 modified as described above, with an average isocyanate functionality of from 2 to 2.8 (preferably from 2.1 to 2.7) containing 4,4'-diisocyanatodiphenyl methane as the main component (amounting to more than 40 wt. %) The amine produced according to the present process can be used alone, part;cularly where it still contains unreacted diamine. It is reacted in the RIM process at an isocyanate index of from 90 to 110.
Known mold release agents may be used to produce molded articles which have excellent mold release characteristics. Such internal mold release agents are among the auxiliary agents which may advantageously be used in the process of the present invention. In principle, any mold release agent known in the art may be used ;n the present invention but internal mold release agents such as those described, for example, in German Offenlegungsschrift 1,953,~37 (U.S. Patent 3,726,952), German Offenlegungsschrift 2,121,670 (British Patent 1,365,215), German Offenlegungs-schrift 2,431,968 (U.S. patent 4,098,731) German Offen-legungsschrift 2,404,310 (U.S. patent 4,058,492) and U.S.
Patents 4,519,965 and 4,581,386 are preferred. Preferred mold release agents include the salts (containing at least 25 aliphatic carbon atoms) of fatty acids having at least 12 aliphatic carbon atoms and primary mono-, di- or polyamines containing two or more carbon atoms or amines containing amide or ester groups and having at least one primary, secondary or tertiary amino group; esters of mono- and/or polyfunctional carboxylic acids and polyfunctional alcohols containing saturated and/or unsaturated CO~H and/or OH groups and having hydroxyl or acid numbers of at least five, ester type reaction products of ricinoleic acid and long chained fatty acids; salts of carboxylic acids and tertiary amines; and natural and/or synthetic oils, fats or waxes. Also preferred are the zinc salts described in U.S. Patents 4,519,965 and 4,581,386.

Mo-3598 The oleic acid or tall oil fatty acid salts of the amine containing amide groups which has been obtained by the reaction of N-dimethylaminopropylamine with oleic acid or tall oil fatty acid is particularly preferred.
Apart from the above-described preferred mold release agents, other mold release agents known in the art may in principle be used either alone or in a mixture with the preferred mold release agents. ~hese additional mold release agents include, for example, the reaction products of fatty acid esters with polyisocyanates (according to German Offenlegungsschrift 2,319,648); the reaction products of polysiloxanes containing reactive hydrogen atoms with mono-and/or polyisocyanates ~according to German Offenlegungsschrift 2,356,692 (U.S. Patent 4,033,912); esters of mono- and/or polycarboxylic acids and polysiloxanes containing hydroxyl groups (according to German Offenlegungsschrift 2,363,452 (U.S.
Patent 4,024,090)); and salts of polysiloxanes containing amino groups and fatty acids (according to German Offenlegungs-schriftten 2,417,273 or 2,431,968 (U.S. Patent 4,098,731)).
If an internal mold release agent is used, it is generally used in an amount which totals from 0.1 to 25 wt.X
preferably 1 to 10 wt. % of the whole reaction mixture.
No catalyst is required for the reaction between isocyanate groups and isocyanate reactive groups. However, 25 catalysts known and commonly used in the production of polyurethane foams and microcellular èlastomers are included in the group of auxiliary agents and additives appropriate to the present invention.
Su;table catalysts include tertiary amines such as triethylamine, tributylamine, N-methyl-morpholine, N-ethyl-30 morpholine, N-cocomorpholine, N,N,N',N'-tetramethylethylene diamine, l,4-diazabicyclo(2,2,2)-octane, N-methyl-N'-dimethyl-aminoethyl piperazine, N,N-dimethylbenzylamine, bis-(N,N-diethylamino)-adipate, N,N-diethyl benzylamine, pentamethyl diethylene triamine, N,N-dimethylcyclohexylamine, N,N,N',N'-Mo-359~

206~191 tetramethyl-1l3-butane diamine, 1,2-dimethylimidazole and 2-methyl-;midazole.
~ rganometallic catalysts may also be used in the practice of the present invention. Particularly useful organometallic catalysts include organic tin catalysts such as tin(II) salts of carboxylic acids (e.g., tin-(II)-acetate, tin-(II)-laurate) and the dialkyl tin salts of carboxylic acids (e.g., dibutyl-tin-diacetate, dibutyl-tin-dilaurate, dibutyl-tin-maleate or dioctyl-tin-diacetate) alone or in o combination with tertiary amines. Other suitable catalysts and details concerning the action of these catalysts are given in Kunststoff Handbuch, Volume Vll, published by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 1966, e.g., on pages 96 to 102.
If a catalyst is used, quantities of about 0.001 to 10 wt.% preferably 0.05 to 1 wt. % (based on component c)) are appropriate.
The products of the process of the present invention are preferably molded elastomeric articles. Blowing agents may 20 be used to produce molded articles having a compact surface and a cellular interior. The blowing agents used may be water and/or readily volatile organic substances and/or dissolved inert gases.
Examples of suitable organic blowing agents include 25 acetone; ethylacetate; methanol; ethanol; halogen-substituted alkanes such as methylene chloride, chloroform, ethylidene chloride, vinylidene chloride, monofluorotrichloromethane, chlorodifluoromethane and dichlorofluoromethane; and butane, hexane, heptane or diethyl ether.
Nitrogen, air and carbon dioxide are examples of suitable inert gases.
The effect of a blowing agent may also be obtained by the addition of compounds which decompose at temperatures above room temperature to release gases, for example nitrogen. Azo compounds such as a~oisobutyric acid nitrile are examples of Mo-3598 206S19i such compounds. Other examples of blowing agents and details concerning the use of blowing agents may be found in Kunststoff Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 1966, e.g., on pages 108 and 109, 453 to s 455 and 507 to 510.
In accordance with the present invention, surface active additives (emulsifiers and foam stabilizers) may also be used as reaction mixture components. Suitable emulsifiers include the sodium salts of ricinoleic sulfonates or of fatty o acids or salts of fatty acids and amines (such as oleic acid diethylamine or stearic acid diethanolamine). Alkali metal or ammonium salts of sulfonic acids (e.g., of dodecyl benzene sulfonic acid or of dinaphthyl methane disulfonic acid) or of fatty acids such as ricinoleic acid or polymeric fatty acids may also be used as surface active additives.
If foam stabilizers are used, it is preferred that they be water soluble polyether siloxanes. These compounds are generally a copolymer of ethylene oxide and propylene oxide linked to a polydimethyl siloxane group. Foam stabilizers of this type are described in U.S. 2,764,565.
Other auxiliary agents and additives which may optionally be used in the process of the present invention include known cell regulators (such as paraffins or fatty alcohols or dimethyl polysiloxanes), known pigments, dyes and flame retarding agents (e.g., tris-chloroethyl phosphate and polyphosphate), stabilizers against aging and weathering, plasticizers, fungistatic and bacteriostatic substances, and fillers (such as barium sulfate7 glass fibers, kieselgur or whiting~.
Other examples of suitable surface active additives and foam stabilizers, flame retardants, plasticizers, dyes, fillers and fungistatic and bacteriostatic substances and details concerning the use of mode of action of these additives may be found in Kunststoff Handbuch, Volume VII, published by Mo-3598 ~ieweg and Hochtlen, Carl Hanser Verlag, Munich 1966, e.g., on pages 103 to 113.
When carrying out the process of the present invention, the quantity of polyisocyanates should preferably be 5 sùch that the isocyanate index is from 70 to 130, most preferably 90 to 110 in the reaction mixture.
The process of the present invention is carried out by the known reaction injection molding techn;que (RIM
process). Two streams are generally employed in this molding techn;que. In the present invention, the polyisocyanate (component a)) is the first reactant and the "polyamine componentl' is the second reactant. If any auxiliary agents or additives are used, they are generally mixed with the "polyamine component". However, it may be advantageous, for example when using a mold release agent containing isocyanate groups, to incorporate the release agent with the reactant polyisocyanate (component a)) before the process of the present invention is carried out. It is possible in principle to use mix heads in which three or four separate components may be 20 simultaneously introduced so that no preliminary mixing of the individual components is required. The quantity of reaction mixture introduced into the mold is generally calculated to produce molded articles having densities of from 0.8 to 1.4 g~cm3, preferably from 0.9 to 1.2 gtcm3. When mineral fillers 25 are used, however, the molded articles may have densities above 1.2 g/cm3. The articles may be removed from the mold after they have been left in there from 5 to 90 seconds, preferably from 20 to 60 seconds.
The invention is further illustrated but is not 30 intended to be limited by the following examples in which all parts and percentages are by weight unless otherwise specified.
EXAMPLES
The n-chloroformates are prepared by a phosgenation procedure as follows:

Mo-3598 206~191 ,9 CHLOROFORMATE A: To 3007 parts of a stirred polyoxypropylene glycol (OH number of about 56) were added about 330 parts of gaseous phosgene by means of a bubbling tube. The rate of addition was such that the reaction s temperature did not exceed 40C. Vaporized phosgene was returned to the reaction flask by a reflux condenser which was cooled at less than O'C. The mixture was stirred for an additional 2 hours after the addition was complete. The warm solution was purged with nitrogen to remove any excess phosgene o and hydrogen chloride. The polyether polyol was found to be 95.6X converted to the chloroformate.
Using the identical process, the following additional chloroformates were prepared using the materials and amounts indicated and with the % conversion indicated:
CHLOROFORMATE B: 2400 parts of a polyether ~4800 molecular weight glycerine/propylene oxide/ethylene oxide adduct, with the ethylene oxide being present as a 17% by weight termi-nation) and 165 parts of gaseous phosgene were used. Conver-sion amounted to 98.8~.
CHLOROFORMATE C: 2490 parts of a polyether (4980 molecular weight glycerine/propylene oxide adduct) and 165 parts of gaseous phosgene were used. Conversion amounted to g9.2%.
CHLOROFORMATE D: 3000 parts of a polyether 51000 molecular weight propylene glycol/propylene oxide adduct) and 499 parts of ga~eous phosgene were used. Conversion amounted to 84X.
CHLOROFORMATE E: 3000 parts of a polyether (3000 molecular weight glycerine/propylene oxide adduct) and 253 parts of gaseous phosgene were used. Conversion amounted to 85%.
CHLOROFORMATE F: 3000 p~arts of a polyether (1500 molecular weight glycerine/propylene oxide adduct~ and 493 parts of gaseous phosgene were used. Conversion amounted to 83%.
Mo-3598 206~191 CHLOROFORMATE G: 3000 parts of a polyether (1000 molecular we;ght propylene glycol/propylene oxide adduct) and 654 parts of gaseous phosgene were used. Conversion amounted to 98.3%.
CHLOROFORMAT~_~: 3000 parts of a polyether (a 1:1 mixture of 2000 molecular we;ght propylene glycol/propylene ox;de adduct and a 3000 molecular weight glycerin/propylene oxide adduct) and 327 parts of gaseous phosgene were used.
Conversion amounted to 98~.

In preparing the amine materials herein, the following materials were used:
DETDA: an 80/20 m;xture of methyl-3,5-d;ethyl-2,4-d;aminobenzene and l-methyl-3,5-d;ethyl-2,6-diaminoben~ene.
TBTDA: t-butyl toluene diamine.
m-TDA: a mixture of about 77% 2,4-toluene diamine, 19% 2,6-toluene diamine, and the balance the 2,3- and 3,4-isomers.
THF: tetrahydrofuran.
~: toluene.

A two liter flask was charged with 100 parts ortho-toluene diamine (consisting of 40~0 of the 2,3-isomer and 60X of the 3,4-isomer) and 1 liter of THF. To this were added, over a I hour period, 468 parts of CHLOROFORMATE B while maintaining the temperature at 32-C. To the resulting solution, which contained the hydrogen chloride salt of the toluene diamine, were added 4.8 parts of a 50~0 solution of sodium hydroxide. The solvent was then removed by distillation with the last of the solvent being removed under a full pump vacuum at ll5-C. The resultant product was filtered to remove the solid sodium chloride to afford a clear dark liquid having a viscosity at 25'C of 6880 mPa.s and an amine number of about 112.
Mo-3598 206~191 The material was then passed through a thin film evaporator to remove ortho-TDA to give a clear dark liquid having a viscosity of 5120 mPa.s and an amine number of 30.9.

Using the identical procedure, the products noted in Table 1 were obtained without the thin film evaporator step.
In Example 3, the thin film evaporator was used. The materials used, the amounts of materials used, the conditions and results were as set forth in Table 1.

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~- 3598 RIM Examples In the RIM examples which follow, the following materials were used:
POLYAMINE: as described in Examples 1, 3, 5 and 19 as noted.
~-4050: a propylene oxide/ethylene diamine adduct having an OH number of 630.
DETDA: an 80:20 mixture of 1-methyl-3,5-diethyl-2,4-and -2,6-diaminobenzene.
DB OIL: a castor oil aYailable from CasChem.
L-5304: a silicone surfactant available from Union Carbide.
IMR: a non-isocyanate-reactive material prepared by reacting neopentyl glycol with a polymerized fatty acid (Pripol 1009, available from Unichema~ to form a 130 OH number ester and then reacting the ester with stearic acid to an average molecular weight of about 1~00.
ISO A: a blend of (i) 20 parts by weight of a polymethylene poly(phenylisocyanate) having an NCO content of 32.5%, containing 19YO by weight of the 2,4-isomer, and having an isocyanate functionality of about 2.4, and (ii) 80 parts by weight of a 19YO isocyanate content prepolymer prepared by reacting a blend of a) 56 parts of 4,4'-methylebis(phenylisocyanate) and b) 6 parts by weight of a carbodiimde-group mod;fied 4,4'-methylenebis(phenylisocyanate) having an NCO content of 29.3% with c) a 2C00 molecular weight polyester diol (based on adipic acid, 1,4-butane diol and ethylene glycol). The blend of (i) and (ii) has an NCO content of about 21.6% by weight.

ISO B: 797 parts by weight of a polyol (the reaction product of propylene glycol and propylene oxide having an OH number of about 112) were added with stirring over a 14 minute period to 2703 parts of a methylenebis(phenylisocyanate) (a mixture of 27~ by we;ght of the 2,4-isomer and 73% by welght of the 4,4'-isomer with an NCO
content of 33.6%) while holding the temperature between 50 and 60C. After an addit;onal one hour at 50 to 60-C, the reaction mixture was cooled to room temperature. The product was a light yellow, clear stable liquid having an NCO
content of 24.1% and a viscosity at 25C of 130 mPa.s.
IS0 C: 600 parts by weight of a polyol ~the reaction product of propylene glycol and propylene oxide having an OH number of about 112) was reacted with 2400 parts of a polymethylenepoly(phenyl-isocyanate) (a mixture of 25% by weight of the 2,4-isomer, 55% by weight of the 4,4'-isomer and 2~o by weight of higher homologues, with the m;xture having an NCO content of 32%). The product was a dark, clear stable liquid having an NCO content of 24.1% and a viscosity at 25'C
of 225 mPa.s.
RIM plaques were prepared using a laboratory piston metering unit and a clamping unit. The metering unit was a two component instrument having a maximum metering capacity of 0.6 liters. A 300mm x 200mm x 3mm rectangular mold was used to mold the samples under the following conditions:

Component A (;socyanate~ temperature: 40 C
Component B temperature: 60-C
Isocyanate index: 105 Mold temperature: 65-C
Mix presuure: 2646 psi Demold time: 45 seconds The formulations used and the physical properties were as Tndicated in the follow;ng table. The samples were tested for density (ASTM D-792), flex modulus (ASTM D-638), o elongation (ASTM D-638), heat sag (ASTM D-3769), notched Izod ~ASTM D-256), and tear strenght "C" (ASTM D-624).
TABLE

B-side, pbw POLYAMINE from Example 1 65.25 - - -POLYAMINE from Example 3 - 65.25 20POLYAMINE from Example 19 - - 91.25 POLYAMINE from Example 5 - - - 91.25 M-4050 3.0 3.0 3.0 3.0 DETDA 26.0 26.0 IMR 3.0 3.0 3.0 3.0 DB OIL 2.0 2.0 2.0 2.0 L-53~4 0.75 0.75 0.75 0.75 A-Side, pbw ISO A 75.2 75.2 ISO B - - 69.9 ISO C - - - 75.6 Mo-3598 RIM EXAMPLE NUM~ER 1 2 3 4 RESULTS
Density, g/cm3 1.08 1.07 1.05 1.06 Flex mod., N/mm 570 559 6~8 1047 Elongaation, % 156 150 143 28 Tear str., N/mm 103 107 83 76 Izod, N-mm/mm 379 391 327 226 Heat sag, mm 10 cm 163~C 7.5 5.7 8.7 10.0 15 cm 135DC 4.8 5.2 5.8 8.3 ~he processing was excellent in each instance.
Although the invention has been described in detail in the foregoing for the purpose of illustrat;on, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.

Mo- 3598

Claims (9)

1. A process for the preparation of an aromatic amine comprising reacting (a) an n-chloroformate of an n-hydroxyl functional material, said n-hydroxyl functional material having a molecular weight of from about 200 to about 12,000, and wherein n is an integer of from 2 to 6, with (b) an aromatic diamine having a molecular weight of from 106 to 400 in a ratio of 1 or more moles of aromatic diamine per chloroformate equivalent.

2. The process of Claim 1, wherein the molecular weight of said n-hydroxyl functional material is from 500 to 6000 and n is either 2 or 3.

3. The process of Claim 1, wherein said diamine contains only primary amine groups.

4. The process of Claim 1, wherein the reaction is conducted in the presence of a solvent.

5. The process of Claim 1, wherein said n-hydroxyl functional material is a polyether.

6. The process of Claim 1, wherein said ratio is 2 or more moles of aromatic diamine per chloroformate equivalent.

7. The product produced according to the process of Claim 1.

8. The product of Claim 7 having a viscosity at 25°C
of 20,000 mPa.s or less.

9. In a process for producing a molded elastomer by reacting an isocyanate with an isocyanate-reactive component in a closed mold via the RIM process, the improvement wherein said isocyanate reactive composition comprises the product of Claim 1.