CA1271775A - Isocyanate derivatives containing carbodiimide groups, a process for their production and their use as additives for aqueous solutions or dispersions of plastics - Google Patents

Abstract

ISOCYANATE DERIVATIVES CONTAINING CARBODIIMIDE GROUPS, A PROCESS FOR THEIR PRODUCTION AND THEIR USE AS ADDITIVES
FOR AQUEOUS SOLUTIONS OR DISPERSIONS OF PLASTICS
ABSTRACT OF THE DISCLOSURE
The present invention is directed to isocyanate derivatives containing about 2 to 30% by weight of carbodiimide groups, -N=C=N-, on a statistical average at least about 0.8 carbodiimide groups per molecule, about 5 to 200 milliequivalents per 100 g of solids of chemically incorporated sulfonate groups and, option-ally, 0 to about 25%, based on solids, of chemically incorporated ethylene oxide units, -CH2-CH2-O-, in polyether chains. The present invention is also directed to a process for the preparation of these isocyanate derivatives and to their use as additives for aqueous dispersions or solutions of plastics containing carboxyl groups or groups convertible into carboxyl groups.

Description

~ ~ ~; Mo-~771 ISOCYANATF DF,~TVATIVES CONTAI~1INC. CARBODIIMIDE GROUPS, A PROCESS FOR THETR PRODUCTION A~D T~EIR USE AS ADDITIVES
FOR A~UEOUS SOLUTIONS OR DISPF,RSIONS OF PLASTICS
BACK~7ROUND OF T~E INVF.~TION
Field of the Invention This invention relates to new isocyanate derivatives containing carbodiimide and sulfonate groups, to a process for their production by the at 1east partial carbodiimidization of organic polyisocya-nates followed by reaction of any free isocyanate groupsstill present with compounds containing isocYanate-reactive groups (the starting materials and/or re~ctants used being inter alia compounds containing sulfonate groups) and to the use of the isocyanate derivatives containing sulfonate groups as additives for aqueous dispersions or solutions of plastics containing incorporated carboxvl groups and/or incorporated groups convertible to carboxyl groups.
Description of the Prior Art Aqueous solutions or dispercions of ionically modified plastics are known in large numbers. Thus, the production of polyurethane dispersions or solutions optionally containing urea groups is described, for example, in DE-PS 1,178,586, DE-PS 1,184,946, DE-OS
1,495,745, DE-OS 1,770,068, DE-OS 2,314,512, DE-OS

2,446,440, DE-OS 2,543,091, DE-OS 2,642,~73, US-PS

3,480,592, US-PS 3,388,087, US-PS 3,479,310, US-PS
3,756,992, US-PS 3,905,929 and in "Angewandte Chemie"
82, 53 et seq (1970).
The production of aqueous or water-dilutable polycondensates, more especially polyester resins, optionally containing organic solvents and/or urethane groups, is also known (cf. DE-OS 2,225,646, DE-AS
2,239,094, DE-OS 2,446,439, US-PS 3,,76,582, US-PS

4,029,617, cf. also Houben-Weyl. "Methoden der Organi-schen Chemie" XIV/2 (1963), pages 3Q et seq).

LeA 23 621-US

~77S
- ~ -The productior of pol~ers, more espPcially polvacrylates, containlng incorporated ionic groups is also known (cf. for example Houben-Wevl "Methoden der Organischen Chemie" XTV/1 (19~1), pages 103 et seq or XIV/~ (1963), page 754).
The solubilitv or dispersibility of these plastics in water is often ensured by carboxvlate groups chemically incorporated in the p]astics which contain as counterions ammonium cations based on a~monia or thermally volatile organic amines. When drving the sheet-form materials (coatings) produce~ from solution.s and, more especially, dispersions of the type in question (which is generally carried out by heatirg?s many of the carboxJlate groups originally present are converted into carboxyl groups through elimination of the a~onia or amine counterion, the carboxyl-containing plastics then present often show unsatisfactory resist-ance to water. In addition, these carboxyl groups catalytically accelerate the obviously undesirable hydrolytic degradation of plastics containing ester groups which c2n result in rapid deterioration of the mechanical properties of the abo~re-mentioned sheet-for~
ma~erials, especially in a damp atmosphere.
Accordingly, the object of the present invention is to provide an additive for aqueous solutions and, more especiall~T, dispersions of plastics containin~ carboxyl groups and/or carboxylate groups convertible into carboxyl groups which ensures that, before or during drying of the sheet-form materials produced from the solutions or dispersions, the carhox~Tl groups are converted into l~rgely non-hydrophil-,c groups which have no catalvtic effect on the hvdrolytic degradation of any ester groups present in the plastics.
At the same tire, the conversion of the carboxvl groups Mo-27,1 ~27~7~s into the non-hvd-ophilic groups mentioned is to be accompanied by crosslinking of the sheet-form materlal in order thus to improve its mechanical properties and, in particular, its wet strength.
This obiect i.s achieved by providing isocyanate derivatives containing carbodiimide groups according to the invention which are described in more detail herein-flfter. Although h~drophilic groups are also present in - the isocyanate derivatives accordin~ to the invention, the concentration in which they are present is generally cor..ciderablv lower so that, through the use of the additives flccording to the invention, the hydrophilicity of the plastics can be very considerahly reduced (i) by reducing the total concentration of hydrophilic g-oups and (ii) through the crosslinking effect mentioned above.
SU~.ARY ~F THE I~VEMTIO~
The present invention relates to isocyanate derivatives which contain about 2 to 30% by weight of carbodiimide groups -N=C=N-, on a statistical average at least about 0.8 carbodiimide groups per molecule, about 5 to 200 ~illiequivalents per lQ0 g of solids of chemicallv incorporated sulfonate groups and, option-ally, 0 to about 25% by weight, based on solids, of chemically incorporated ethylene oxide units -C~2-CH2-O-in polyether chains.
The present invention also relates to a process for producing the isocyanate derivatives containing carbodiimide groups bv at least partial carbodiimidiza-tion of the isocyanate groups of a) organic polyisocvfl-nates or a miY.ture of organ c polv- and monoisocvanates having an average NCO-functionality of about 1.3 to 2.5 followed bv reaction of any free isocvanate groups still present in the carbodiimidiza~ion product with b) mono-Mo-2771 ~L2~i7;~;
and/or polyfunc~ional compounds containing isocvanate-reactive groups in such an equivalent ratio that, for every isocyanate group, there is at least one isocyanate-reactive group, characterized in that at least a portion of the compounds used as components a) and/or b) are compounds containing chemicallv incorpo-rated su]fonate groups or groups convertible into sulfonate groups by a neutralization reaction, any groups convertible in sulfonate groups still present on completion of the reaction being completely or partlv converted into sulfonate groups by neutralization, the tvpe of and quantitative ratios between the reactants, the degree of carbodiimidization and, optionally, the degree of neutralization being selected in such a way that the end products have the above-mentioned contents of carbodiimide and sulfonate groups.
The present invention also relates to the use of the isocyanate derivatives containing carbodiimide ~roups as additives for aaueous dispersions or solutions of plastics containing carboxyl groups and/or groups convertible into carboxvl groups.
DETAILED DESCRIPTJO~I OF THE INVEMTION
US-PS 2,937,164 describes certain monocarbo-diimides as "crosslinkers" for linear, synthetic po]~ers containing carboYvl or sulfonyl ~roups.
However, there is no mention of carbodiimides containing sulfonate groups of the same type as the products accordin~ to the invention. In addition, the described monocarbodiimides are attended by the disadvantage th~t they are monofunctional ir their reactivity to carboxyl ~roups and, accordingly, are not crosslinkers in the strict sense of the term.
EP-OS 121,083 describes the use of aliphatic, cycloaliphatic or aliphatic-cvclo21iphatic polycarbo-Mo-2771 diimides for latices containin~ carboxyl groups. Once a~ain, there is no mention of carbodiimides containing su1fonate groups of the type according to the invention.
In addition, it is emphasized in this prior publication that aromatic carbodiimides are not ~suitable ior the stated purpose; wherea~s, according to the invention, aromatic carbodiimides in particular are especially suitable as discussed in more detail hereinafter. In addition, if the polycnrbodiimides described in EP-OS
]21,Q83 are to be used in aqueous systems, the products have to be cor.verted into a~ueous emulsions by means of external emulsifiers using special stirring units. ~ot onlv is this very expensive, it is also attended by the disadvantage that, in the sheet-form material ultimatelv ohtained, the chemically non-fixed emulsifiers migrate to the surface where they can give rise to undesirable effects. It is stated in EP-OS 121,083 that the polycarbodiimides mav be converted nto a cationically modified salt by reaction with dimethylaminopropylamine and subsequent salt formation with p-toluene sulfonic acid methylester or with dimethyl sulfate which makes the products soluble in water so that there is no need to use an eY~ternal emulsifier,. ~owever, the disadvan-tage of this procedure is that in combination with anionic dispersions, the cationically modified additives, inevitably lead to compatibility problems.
Thus, there is no Example in EP-~S 121,083 which relates to the use of a cationically modified additive as crosslinker for dispersions containing carboxylate group.s.
The isocyanate derivatives described in detai1 hereinafter are favorably distin~uished in many respects from the ahove-mentioned, state-of-the-art additives containing carbodiimide groups:

~o-2771 1. Through the ircorporation of (anionic) sulfonate groups and optionally hvdrophilic eth,vlene oxide units, the isocyanate derivatives according to the invention mav readilv be added to aqueous solutions and, more especially, dispersions of plastics containing carboxylate and/or carbox,Tl groups.
2. The degree of crosslinking of the 6heet-form material ult.mately obtained may be adjusted according to the carbodiimide group content of the additives according to the invention which may readily be varied according to the type of and quantitative ratios between the starting materials used.
3. The isocvanate derivatives containing carbodiimide groups according to the invention which are suitable for the use according to the invention are not confined to those containirg aliphatically or cycloaliphatically bound carbodiimi.de groups.
Instead, it ha~s been found that compounds according to th~ irvention of which the carbodiimide groups are a~omatically bound, i.e. which may be produced from inexpensive aromatic starting isocyanates, are particularly suitable for the above-mentioned application.
Starting materials for the process according to the invention are a) organic polyisocYanates having ar.
(average) NCO-functionality of about 2.0 to 2.5 or mixtures of organic poly- and monoisocyanates having an a~rerage NCO-functionalitY of about 1.3 to 2.5 and, optionally, b) compour.ds containing isocyanate reactive groups and havi.ng a functionality of one or higher in th~ context of the isocyarate additi.on reaction, being used as at least a portion of starting materials a) and/or b) being compounds containirg sulfonate group.s.

Mo-2771 The synthesis components a) inclu~e ~I) any aliphatic, cycl~aliphatic, araliphfltic, aromatic or hete~ocyc].ic polyisocyanates of the type described, for example, bv W. Siefken in Justus Liebigs Ann~len der Chemie, 562, pages 75 to 136. Preferred polyisocyanates al) include the commerciallv available diisocyanates such 2S hexameth~v~ene dii~soc~anate, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane and, in particular, aromatic diisocyanates such as 2~4- and, optionally, 2,6-diisocyanatotoluene or 4,4'- and, optionallv, 2,4'-diisocyanatodiphenylmethane, 3,4'-diisocyanato-4-methv].diphenylmethane or 3,2'-diiso-cyanato-4-methYldiphenylmethane and isomers thereof or mixtures of these diisocyanates. However, particularly preferred diisocyanates are phenylene diisocyanates sterically hindered by alkyl substituents such as l-methyl-3,5-diethyl-2,4-diisocyanatobenzene, l-methyl-3,5-diethyl-2,6-diisocvanatobenzene and mixtures of these two diisocyanates, 1,3,5-triisopropyl-2,4-diiso-cvanatobenzene or alkyl-substituted phenylene diisocya-nates of the type described, for example, in US-PS
3,105,845 or DE-OS 3,317,649.
Other starting materials a) inclu~e a2) hvdrophilically modified polvisocyanates, includin~
both polvisocyanates containing sulfonate groups or groups convertible into sulfonate groups by a neutrali-zation reaction of the type described, for example, in US-PS 3,959,329 and also mono- or diisocyanates contair.ing ethvlene oxide units incorporated in polvether chains of the type de.scribed in D~-OS
2,314,5~2, DE-OS 2,314,513, DE-OS 2,551,094, DE-OS
2,651,506, US-PS 3,92.0,598 or US-PS 3,905,929. The slllfonated diisocYanate ohtained by reaction of 2,4-diisocyanatotoluene with equimolar quantities O.c Mo-2771 ~2n~

chlorosulfonic acid at room temperature in the presence of solvents such as 1,2-dichloroethane, is another suitable compound containing groups convertible into sulfonate groups with neutralizing agents such as triethylamine. Where compounds such as these are used as component a2~, the neutralization step is carried out after the reac~ion.
However, particularly preferred hydrophilically modified polyisocyanates are NCO-prepolymers of the type obtained by reaction of excess quantities of the diisocyanates mentioned by way of example under al), especially the sterically hindered phenylene diisocyanates, with diols containing sulfonate groups.
In the production of these NCO-prepolymers, the starting materials are generally reacted in an NCO:OH-equivalent ratio of about 1.2:1 to 10:1 at a temperature of about 20 to 150C. Diols containing sulfonate groups which are particularly suitable for the production of the NCO-prepolymers are, in particular, those corresponding 20 to the following general formula H-(01CH-CH2)n-0-(A)o~CH~(B) -0-(CH2-CH-0) H
CH3 ¦ CH3 (CX2) ~O3~ q X
in which A and B may be the same or different and represent difunctional aliphatic hydrocarbon radicals containing 1 to 6 carbon atoms, 30 R represents hydrogen, an aliphatic hydrocarbon radical containing 1 to 4 carbons or a phenyl radical, Mo-2771 ~27i~5i _9_ X~ represents an alkali metal cation or an optionally substituted am~onium group, n and m may be the same or different and represent rumbers from 0 to ~bout 30, o ~nd p each have a value of 0 or l and q is an integer from 0 to 2.
The production of these sulfonate diol~ is described, for e.xample, in DE-AS 2,446,440 and in US-PS
4,108,814. Particularly preferred sulfonate diols o~
this type are those in which m and n may be the same or different and each have a value from 0 to 3.
Further s~rting materials a) include a3) organic monoisocyanates such a~s n-hexyli.socyanate, phenvlisocyanate or p-tolvlisocyanate. As alreadv mentioned, however, these monoisocyanates are used in admixture with organic polyisocyanates of the type mentioned bv way of example, the mixture having an average NCO-functionality of about 1.3 to 2.5 and preferablv of about 1.3 to 2.
Component a) may also contain other modified polyisocyanates, for example reaction products of excess quantities of organic diisocyanates of the type mentioned bv way of example under al) with di- or trihydroxyalkanes having a molecular weight below about 400 .such as ethylene glycol, propvlene glycol, tetra-methylene diol, hexamethylene diol, trimethvlol propane and/or glycerol.
The synthe.sis components b) optiona3.1y used in the process according to the invention include bl) polyh~rdric, more especially di.hydric alcohols havir.
a molecular weight below about 400 such as for example ethylene glycol, propvlene glycol, tetramethylene diol, hexamethylene diol, octamethylene diol, neopent~.71 glycol, 2-methyl-1,3-dihvdroY.ypropane, g3ycerol, Mo _ 2771 ~7~7s trimethvlol propane, diethylene glycol, trieth~lene glvcol, tetraethylene glycol, polyethylene glvcols having a molecular weight in the above-mentioned range, dipropvlene glycol, tr~propylene glvcol or mixtures of thesP polyhvdric alcohols.
Other optional synthesis components b) include b2) polvfunctional, preferably difunctional amines having a molecular weight helow about 400 and containing at least two primary and/or secondary amino groups such as 1,2-diaminoethane, hexamethylene diamine, piperazine, l-amino-3-aminomethyl-3,5,5-trimethYlcyclohexane, 4,4'-diaminodicyclohexylmethane or mixtures of these amines. The use of amines such as these is less preferred than the hydroxyl-containing components b).
Other optional synthesis components b) include b3) hydrophilically modified monohydric or dihydric alcohols such as the sulfonate diols alreadv mentioned bv way of example under a2) or even compounds containing ethylene oxide units corresponding to the followin~
gener21 formula R' R' Ho-cH-cH2-N-cH2-cH-oH
CO-NH-R-NH-CO-X-Y-R"

in which R represents a difunctional radical of the type obtained by removir.g the isocyanate group~q from a diisocyanate R(NCO)? of the tvpe mentioned above under a]), R' represents hydrogen or a monofunct.ional hydrocarbon radical containing 1 to 8 carbon atoms, preferablv hydro~en or a methvl group, Mo-2771 ~5 R" represents a monoflmctional hydrocarbon rAdical containing 1 to 12 carbon atoms, preferably an unsubstituted alkvl radical containing 1 to 4 carbon atoms, X represents a polvalkylene oxide chain which contains about 5 to 90 and preferably about 20 to 70 members of which at least about 40% and preferably at least about 65% a~e ethylene oxide units whicht in addition to ethylene oxide units, may also contain propylene oxide, butylene oxide or styrene oxide units, propylene oxide units being preferred, Y represents oxygen or -NR"'- where R"' corresponds ir.
its definition to R', The compounds corresponding to the above formu1.ae may be produced by the methods described in D~-OS 2,314,512 and 2,314,513, in addition to the respective disclosures of which it is pointed out that, instead of the monohydric polyether alcohols mentioned therein as starting materials~ it is also possible to use polyether elcohols in which the polYether segment -in addition to ethylene oxide units - also contains up to about 60% by weight, based on polyether seg~ent, of propylene oxide, butylene oxide or stYrene oxide urits, preferably propylene oxide units. In special cases, the presence of "~ixed polvether segments" such as these may afford specific advantages.
The hydrophilic monohydric alcohols suitable for use in accordance wlth the invention include, for example, compounds corresponding to the following formula H-X-Y-R"

~o-277]

~12~

in which X, Y and R" are as just defined.
These monohydric, hydrophilically modified alcohols may be produced by the methods described in US-PS Nos. 3,905,929 and 3,920,538, for example by the alkoxylation of suitable starter molecules such as n-butanol with ethylene oxide and, optional]y, other alkylene oxides such as propylene oxide.
Other optional synthesis components b) include b4) aminosulfonates, more especially diaminosulfonates of the type described in CA-PS 928,323, in particular the sodium salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid.
Other optional svnthesis components b) include b5) monohydric alcohols or monofunctional, primary or secondary amines having a molecular weight below about 400. ~ynthesis components such as these include methanol, ethanol, n-butanol, i-butanol, n-octanol, n-dodecanol, methylamin~, ethylamine, n-hexylamine or aniline. These monofunctional components are often used as chain terDinators.
Other option?l svnthesis components b~ include hydrazine, hydrazine ht~drate or hydrazine derivatives such as carboxylic acid h~drazides or semicarbazides.
Am~onia ma~ also be used as svnthesis componen~ b) and is a particularly suitable chain terminator.
The isocyanate derivatives containing carbo-diimide groups according to the invention produced from the starting materials mentioned by way of example contain about 2 to 3n" by ~ei~ht and preferably from 5 to 15% by weight of carbodiimide groups (-N=C=N-) and on a statistical average about 0.8 to ~0, preferably about 1 to 25 and most preferably about 1.? to ~0 such Mo-~771 ~z~r~

carbodiimide groups per molecule. Their content of incorporated sulfonate groups i~ about 5 to 200, preferably about 5 to 150 and most preferably about 5 to 1~0 milliequivalents per 100 ~ solids. Their content of incorporated ethvlene oxide units in polyether chains i~
0 to abcut 25, preferably 0 to about 20 and most preferably 0 to abnut 15% by weight, based or solids.
The hydrophilic groups men~ioned are preferably pr~ent in the compounds according to the invention in such quantities that their solubility or cispersibility in water is guaranteed. ~owever, in addition to the chemicallv incorporated hvdrophilic groups mentioned, it is also possible, although by no means preferred, to use external emulsifiers which are mixed with the compounds according to the invention to guarantee their solubility or dispersibility in water. Emulsifiers such as these include ethoY~ylated nonvlphenol, polyoxyethylene l~urvl ether or polvoxyethylene laurate, oleate or stearate.
These compounds generally contain about 8 to 50 oxyethylene units per molecule.
The content of the above-mentioned groups essential to the inventi~n in the compounds according to the invention is en~ured by appropriately selecting the starting materials, the quantities in which they are used and also the degree o.f carbodiimidization. In the context of the invention, the degree of carbodiimidiza-tlon is understood to b~ the percentage of isoc~anate groups in the starting isocyanates a) which are reacted to form carbodiimide groups. The compounds according to the invention preferably do not contain free isocyan~te groups after their production.
The production of the compounds according to the invention, i.e. the process according to the invention, mav be carried out in various ways.

, ~50-2771 The simplest way of carryin~ out the process according to the invention is to react mixtures of organic polyisocyanates, preferably diisocyanates, with monoisocyanates in such a way that all the isocyanate groups are converted into carbodiimide groups. To this end, isocyanates containing sulfonate groups an~, optionally, ethylene oxide units are used in such a quantity that the resulting product has a sulfonate group content within the above-nentioned limits and the quantitati~re ratio of polyisocyanate to monoisocyanate, i.e. the average NCO-functionality of the isocyanate mixture, is selected in such a way that chain termina-tion takes place during the carbodiimidizat-on reaction, so that the resulting products have a carbodii~ide group content within the above-mentioned range. Chain termination always occurs when the a~erage NCO-function-ality is below 2Ø Accordingly, it is possible, simply by selecting the average ~CO-functionality of the isocyanates used as co~ponent a), to adjust the molecular weight and hence the rumber of carbodiimide groups present on a statistical average in the end products.
In another variant of the process according to the invention, only so~e of the isocyanate groups in starting component a) are carbodiimidized and the free i~socyanate groups still present thereafter are reacted with isocyarate-reactive groups of the type mentioned bv way of example under b), the degree of carbodiimidiza-tion of the first reaction step beirg selected in such a wav that carbodiimide groups are present in the product ultimately obtained in a quantity corresponding to the amounts mentioned above. In this connection, the quantltv in which co~ponent b) is used is always determined in such a way that at least one isocvanate-Mo-~771 ~L2~

reactive group is available for every free isocvanate group present in the partly carbodiimidized isoc~anate.
In this variant of the process according to the invention, the sulfonate groups may be incorporated in the end pr~luct both through component a), for exa~ple by using NCO-prepolymers containing sulfonate groups as at least a portion of component a) and/or throu~h component b), for example by using a sulfonate diol of the tyPe mentioned by way of example above as at least a portion of component b) or even by using diaminosulfon-ates or other compounds containing both isocyanate-reactive groups and incorporated sulfonate groups. In this case, too, the number of carbodiimide groups present on a statistical average in the end products may he determined in advance bv suitably selectin~ the functionality of the starting components, i.e. by an adjustment to the molecular weight made possible in this way. If, for example, the number of carbodiimide groups ir the partlv carbodiimidized isocyanate is sufficient, the reaction with component b) need not be accompanied by chain extension, i.e. chain-terminating sqnthesis components of the t~pe mentioned by way of example are preferably exclusively used a~s component b).
Conversely, in cases where difunctiona] synthesis components b) are at least partly used, a chain-extending reaction may be brought ahout which naturall~,7 increases the number of carbodiimide groups per molecule present on a statistical average in the end products.
In this vari~nt of the process according to the inventlon, component a) preferablv has an NCO-functionalitv of about 1.8 to ?.5 before the carbodiimidization reaction. It is also possible using this variant to produce valuable end products which, on a statistical average, contain a large nu~ber of 1`'10--?771 carhodiimide units corresponding to the details mentioned above with reg~rd to the number of carbo-diimide units.
In the second variant of the process according to the nvention, the ethylene oxide units optionally present in the end products are again incorporated in the end product by using a component a! containing ethylene oxide units and/or by using a component b) containing ethylene oxide units of the type mentioned by wav of example in the foregoing.
In both variants of the process according to the invention, the isocyanate groups in component a) are at least partly carbodiimidized in known manner, for example by any of the methods known from the prior art as represented, for example, by US-PS ~os. 2,840,589 and 2,941,966 or bv DE-OS ~os. 2,504,4no, 2,552,350 and 2,653,120. The at least partial carbodiimidization of the isocyanate groups in component a) is carried out with particular advantage using carbodiimidization catalysts of the type described, for example, in US-PS
Nos, 2,941,966, ~,853,518 and 2,853,473 or in DE-OS
?.,614,3~3, Particularly preferred carbodiimidization catalvsts are l-methvl-1-phospha-2-cyclopentene-1-oxide or 1-me,thyl-1-pho~pha-3-cyclopentene-1-oxide or mixtures of these compounds. Any other state-of-the-art carbo-diimidization catalysts may of course also be used. The at least partial carhodiimidization of component a) is generally carried out using about 0.001 to 5% by weight and preferably about 0.02 to 2% hv weight, based on com~onent a), of carbodiimidization catalysts of the type mentio~ed by way of example at a temper~ture of about 0 to 200C and preferab~y at ~ temperature of about 20 to 150~C. If only some of the isocyanate groups i.n component a) a,e t.o be carbodiimidized, it is Mo-2771 ;~5 advlsable to terminate the carbodiimidization reaction at the desired degree of carbodiimidizatinn bv adding a catalvst poison. Suitable catalyst poisons are described, for example, in DE-O~ 2,614,323.
Preferred catalyst poisons, which are particularly suitable for deactivating the phospholine oxides mentioned by way of example above, include phospknrus trichloride, phosphorus pentachloride or thionvl chloride. The catalyst poisons are generally used in a quantity of at least 100 mole %, based on the catalyst.
In order to obtain partly carbodiimidized isocvanates that are stable in storage at room tempera-ture, it may even be advisable to carry out the carbo-diimidiæation reaction at about 50 to 200C using catalysts which only develop their catalytic activity in this elevated temperature range. Catalvsts such as these are described, for example, by I.I. Monagle in J. Org. Chemistry 27, 3851 (1962). After the required degree of carbodiimidization has been reached, thereaction may be terminated simplv bY conling.
The progress of the carbodiimidization reaction mav be followed frnm the evolution of carbon dioxide and also from the reduction in the NCO-content nf the reaction mixture. In general, the end products obta.ned in the event of partial carbodiimidization are not individual carbodiimides, but instead mixtures of carbodiimides having different contents of carbodiimide units per molecule ard optionally containing unreacted starting isocyanate. Accordinglv, all of the above-mentioned values regarding the carbodiimide group content of the end products and regarding the number of carbodiimide groups per molecule in the end products are based on statistical averages.

Mo-2771 ~æ7~7s The carbodiimidization reaction may be carried out in the presence or absence of solvents. Examples of suitable solvent.s are benzene, toluene, xvlene, cyclo-hexane, chloroben7ene, o-dichlorobenzene, dir.lethyl formamide, perchloroethylene, ethylacetate, butyl-acetate, diethylPne glycol dimethylether, tetrahydro-furan, acetone, methylethvlketone, cvclohexanone and mixture~ o these solvents. The carbodiimidization product produced in the absence of a solvent often solidifies into a hard resin which may be ground into a powder and subsequently used in accordance with the in~ention or further processed by reaction with component b).
The reaction with component b) which may be carried out after the carbodiimidization reaction also takes place in the presence or absence of solvents of the type mentioned by way of example at a temperature of about 0 to 150~C and preferably at a temperature of about 20 to 100C. Where a different component b) is used, the reaction components may be reacted both simul-taneously and also successively, the ratio of the isocyanate gr~ups in the partly carbodiimidized component a) to the isocyanate-reactive groups being about 1:1 to 1:5 and preferably about 1:1 to 1:2. A
particularly preferr~d procedure is one in which diiso-cyanates free from sulfonate groups of the type mentioned by way of example are used as component a).
The carbodiimidization reaction is carried out to such a degree that the necessary quantity of carbodiimide groups is present in the pro~.uct ultimately obtained and the partlv carbodiimidized diisocvarate or diisocyanate mixtur~ thus obtained is reacted with difunctional compounds b) containing sulfonate groups and, optionally, with difunctional compounds b) containing Mo-2771 iz~m ethvlene oxide units in an equivalent ratio of isocyanate groups to isocyanate,-reactive groups o about 1,05:1 to lO:l. The free isocvanate groups still present therearter are reacted with chain terminators of the type mentioned by way of example under b) in an equivalent ratio of isocyanate groups to isocyanate-reactive ~roups of about 1:1 to 1:1.5, preferablv about 1:1, or with a large excess of chain-extending agents of the type described under b), preferably maintaining an equivalent ratio of isocyanate groups to isocvanate-reactive groups of at least 1:2, so that an NCO-free product is formed. In another procedure largely equivalent to this particularly preferred procedure, the partly carbodiimidized diisocyanates are reacted with a mixture of. difunctior.al hvdrophilic synthesis components and chain terminators while maintaining an equivalent -atio of isocvanate groups to isocvanate-reactive groups of about 1:1 to 1:1.5 After the reaction, the solvent used, if anv, may be removed, for example bv distillation. The solvent-free reaction product is generally a solid which may be ta~en up at any time in an organic solvent or which may even be used in accordance with the invention without using solvents. To this end, the compounds according to the invention ma.v be added to the plastics dispersions in the forr.l of aqueous so'lutions o- disper-sions or even as solids.
The compound~s according to the invention are used in particular as additives for aqueous solutions and, more especially, dispersions of plastics contain'nF
carboxvlate groups and/or carboxv~. groups, the counter-ions of the carboxylate groups preferablv being ammoniu~.
cations based on ammonia or on thermally volatil~

Mo-~771 amines. The use according to the invention is particu-larly suitable for modifying polyurethanes containing carboxylate and/or carbo~yl groups dissolved or dispersed in water, although it is also suitable for modifying polye~ster resins, polybutadi.enes or poly~crvlate resins containing carboxylate groups of the above-mentioned type and/or carboxyl groups in the form of solutions or dispersions in water. The quantity in which the additives according to the invention are used is determined on the one hand by the carboxvlate and/or carboxyl group content of the dissolved or dispersed polvmer and, on the other hand, by the desired proper~y spectrum of the sheet-form material ultimately obtained from the solutions or dispersions. Thus, on the one hand, it may be desirable for the ratio of carboY.ylate groups and/or carboxyl groups in the dissolved or dispersed plastic to carbodiimide groups in the additive to be greater than 1:1 in order to avoid excessive crosslinking of the product, particularly where additives containing more than two carbodiimide groups per mo].ecule are used. On the other hand, the reaction time during the drving of the sheet-form material~s ultimately obtained may be shortened by using at least equivalent quantities of carbodiimide groups, particu-larlv in the case of (on a statistical average) at leastdifunction~] carbodiimides.
The solutions or dispersions of polymers containing carboxylate groups of the type mentioned and/or carboxyl groups, more especially the correspond-ing aqu~ous polvurethane dispersions, which have a totfllcontent of carboxylate groups and carboxyl groups of about 0.2 to 200 milliequivalents per 100 g of solics and also containing the additives according to the invention, may be processed in th~ u.sual way at room Mo-2771 1,~7~

temperature or at elevated temperature and dri~d to form sheet-form materials. The particular dr~ing temperature to be applied, which depends above all upon the chemical composition of the mate~_~], may be determined by a simple preliminary test and is generally about 20 to 150~C.
Aqueous solutions, preferablv di~persions of ~'astics cont~ining carboxylate groups and, optionall , carboxyl groups, more especiallv polvurethares, which contain the additives according tn the invention mav be used with particular advantage for the production of high-quality coatings on a variety of differPnt substrates such as leather, textiles, paper, wood, meta]s, glass and plastics. The coatings ultimately obtained being considerably more water-resistant compared with system.s which have not been modified in accordance with the in~ention.
In the following examples, all the percentages are percentages by weight.
E~ LES
EY~LE 1 178 parts by weight (0.775 mole) of a mixture of 3,5-diethyl-?,4-tolvlene diisocyanate and 3,5-diethvl-2,6-tolvlene diisocyanate ~ratio 7:3) were reacted with 118 parts by weight (0.275 mole) of a propoxylated adduct of 2-butene-1,4-diol and ~aHSO3 (molecular weight 430) for 70 minutes at 80C to an ~CO-value of 14.19%. The reaction product was cooled to 80C and dilnted with 20Q parts bv weight of N-methvl pvrrolidone. After the addition of 59.5 parts bv wei~ht (0.5 mo]e) of phenvlisocyanate, the carbodiimidization reaction was started with 5 ml of a 25% solution of a technical mixture of l-methyl-l-phospha-2-cvclopentene-]-oxide and l-methvl-l-phospha-3-cyclopentene-1-oxide in Mo-2771 N-methy] pYrrolidone t"phospho]ine oxide"), the temperature being ircreased to 120C. After a reaction ~ime of 5 hours, the NCO-content had fallen to 0%.
After cooling to 60C, the reaction was terminated bv adding 2 ml of phosphorus trichloride.
A solution was obtained which had a solids content of 61% by weight, a carbodiimide ~roup (-N=C=N-) content of 9.0% by weight, based on solids, and an S03-ion content of 88 milliequivalents per 100 g of solids. The product contained on average 3 carbodiimide units per molecule.

186 parts by weight (0.65 mole) of 1,3,5-tri-isopropYlbenzere-2,4-diisocyanate were reacted with 137 parts by weight (0.3175 mole) of a propoxylated adduct of 2-butene-1,4-diol and Na~SO3 (molecular weight 430) for 120 minutes at 100C to an ~CO-value of 9.38%. The reaction product was diluted with 200 parts b~,t weight of N-methyl pyrrolidone, fol]owed by the addition of 39.6 parts by weight of phenyl isocyanate, after which the carbodiimidization was started with 5 ml of the phospholine oxide solution mentioned in Example 1 as the temperature being increased to 120C. After a reaction time of 6 hours, the NCO-value had fallen to 0~. After cooling to 60C, the reaction was terminated by adding 1.2 ml of phosphorus trichloride.
A solution was obtained which had a solids content of 64% by weight, a carbodiimide group (-N=C=N-!
content of 5.8% by weight, based on solids, and ar.
S03-ion content of 88 millieauivalents per lnO g of solids. The product contained on average 3 carbodiimide units per molecule.

Mo-2771 (5 EY~ PLE 3 34.7 parts by weight (0.09 mole) of a reactior product of a butanol-started polypropvlene-polyethylene glycol polvether (molar ratio of propylene oxide to ethylene oxide in the alkylene oxide mixture used =
17:83, O~ number 26) with 2,4-tolylene diisocyanate (ethvlene oxide unit content 50% by weight, NCO content 21.8% by weight) and 94.3 parts by weight (0.41 mole) of a mixture of 3,5-diethyl-2,4-tolylene diisocva~ate and 3,5-diethyl-2,6-tolvlene diisocvanate (ratio 7:3) were carbodiimidized at 100C in the presence of 0.5 ml of a 15~ solution of phospholine oxide in N-methvl pvrroli-done as catalyst. At an NCO-value of 13.7%, the reaction mixture was cooled to 60C and the reaction was terminated with 0.2 ml of phosphorus trichloride. The NCO-content settled at a constant 13.1%. After heating to 100C, 67.6 parts by weight of a p~opo~ylated adduct of 2-butene-1,4-dlol and NaH~O~ (molecular weight 430, 70~O in N-methyl pvrrolidone) and 10.3 part.s by wei~ht of n-butanol were added and the reaction was continued to an NCO-value of 0%. The reaction product obtained was dlluted with 95 parts bv weight of N-methyl pyrrolidore.
A solution was obtained which had a ~olids content of 68% by weight, a carbodiimide group (-N=C=N-) content of 7.4~ by weight, based on solids, an ethylene oxide unit content of lOZ by weight, based on solids, and an S03-ion content of 64 milliequivalents per 100 g of solids. The product contained on average 4.6 carbo-diimide units per molecule.
Ey~MpLE 4 115 parts bv weight (0.5 mole) of a mixture of 3,5-diethyl-2,4-t.olvlene diisocyanate and 3,5-diethvl-2,6-tolylene diisocyanate (ratio 7:3) were carbodiimi-dized at 120C with 0.5 ml Or the phospholine oxide Mo-2771 iz~77~

solution mentioned in Example 3 as catalvs~. At an NCO-value of l4.5~, the reaction mixture was cooled to 60C flnd the reaction was terminated by adding 0.2 m] of phosphorus trichloride. The NCO-value .settled at a constant 14.0~. After heating to 80C, 67.6 parts bv weight of a propoxylated adduct of 2-butene-1,4-diol and NaHSO3 (molecular wei~ht 430, 70~ in N-methyl pyrroli-done), 7.2 parts by wei~ht (0.097 mole) of n-butanol and 23.8 parts bv weight of a butanol-started polypropylene-polyethylene glvcol polyether (molar ratio of propvlene oxide to ethylene oxide in the alkylene oxide mixture used 17:83, OH number 26) were added, after which the reaction mixture was diluted with 98.8 parts bv weight of N-methyl pyrrolidone and reacted to an NCO-value of 0%.
A solution was obtained which had a solids content of 60% by weight, a carbodiimide group (-N=C=N-) content of 7.45% by weight, based on solids, an S03-ion content of 61 mllliequivalents per 10Q g of solids and an ethylene oxide unit content of 10.4% by weight, based on solids. The product contained on average 6.2 carbo-diimide units per molecule.

115 parts by weight (0.5 mole) of a mixture of 3,5-diethyl-2,4-tolylene diisocyanate and 3,5-diethvl-2,6-tolvlene diisocyanate (ratio 7:3) were carbodiimi-dized at 100C with 0.5 ml of the phospholine oxide solution mentioned in Example 3 as catalvst. At an NCO-value of 20.8%, 50.8 parts by weight (0.2 mole) of sulfonated 2,4-diisocyanatotoluene dissolved in 102 parts by weight of N-methyl pvrrolidone~ 35.7 parts by weight (0.3 mole) of phenvlisocyanate and 4 ml of the catal37st solution were added and the reaction mixture was diluted with 170 parts by wei~ht of N-methyl Mo-2771 ~s pyrrolidone. The sulfonated diisocyanate was prepared by reacting equimolar quantities of 2,4-diisocyanato-toluene and chlorosulfonic acid at room temperature using 1,2-dichloroethane as solvent. During the reaction in the solvent mentionPd, the sulfonation product precipitates as a solld. To complete the reaction according to the invention, the reaction mixture was carbodiimidized to an NCO-value of 07~ after which the catalyst was destroved with 1 ml of thionyl chloride. 20.2 parts by weight (0.2 mole) of triethyl-amine were then added for salt formatio~ and the NCO-groups released were reacted with 14.8 parts by weight (0.2 mole) of n-butanol.
A solution was obtained which had a solids content Or 4 % by weight, a carbodiimide group (-N=C=N-) content of 13.3% by weight, based on solids, and an S03-ion content of 103 milliequivalents per 100 g of solids. The product contained on average 3 carbodiimide units per molecule.

-111 parts by weight (0.~ mole) of isophorone diisocyanate were carbodiimidized at 140C with 1 part bv weight of the catalyst solution mentioned in Example 1. ~t an NCO-value of 14.7%, the reaction mixture was cooled to 60C, the reaction was terminated by adding 0.5 part by weight of phosphorus trichloride and the reaction product was diluted with 150 parts by weight of N-methyl pyrrolidone. The NCO value settled at a constant 5.67. 86 parts by weight (0.14 mole) of a propoxylated adduct of 2-butene-1,4-diol and NaHSO3 (molecular weight 430, 7Q% in N-methyl pyrrolidone~ and, after 10 minute~s, 3.6 parts by weight (0.05 mole) of n-butanol were ad(led to the reaction mixture which wac then reacted to an NCO-value of Q7O.

~o-2771 i27~

A so~ution was obtained which hfld a carbo-diimide group (-N=C=N-) content of 8.5% by weight, baced on solids, and an SQ3-ion content of 88 millienuivalents per lOn g of solids. The product contained on average 14.4 carbodiimide units per molecule.

115 parts by weight (0.5 mole) of a mixture of 3,5-diethyl-2,4-tolylene diisocyanate and 3,5-diethyl-2,6-tolvlene diisocyanate ~ratio 7:3) were carbodiimi-dized at 120C with 0.2 ml of the catalyst solution mentioned in Example 3. At an NC0-value o~ 26.0~, the reaction mixture was cooled to 60 DC and the reaction was terminated by adding 0.2 ml of phosphorus trichloride.
The NCO-value settled at a constant 26.3%. After heating to 100C, 103.4 parts by weight (0.16 mole) of a propoxylated adduct of 2-butene-1,4-diol and NaHS03 (mol,ecular weight 430, 70% in N-methyl pyrrolidone) ar.d 25.0 parts by weight (0.34 mole) of n-butanol were added, after which the reaction mixture was diluted with 106 parts by weight of N-meth~71 pvrrolidone and reacted to an NC0-value of 0%.
A solution was obtained which had a solids content of 60% by weight, a carbodiimide group (-N=C=N-) content of 2.9% by wei~,ht, based on solids, and an S03-ion content of 82 mllliequivalents per lO0 g of solids. The product contained on averflge 0.9 carbo-diimide units per molecule.
EY~PLE 8 115 parts by weight (0.5 mole) of a mixture of 3,5-diethyl-2,4-tolylene diisocyanate and 3,5-diethyl-2,6-tolylene diisocy?nate (ratio 7:3) were carbodiimi-dized at 120~, with 0.5 ml of the catalvst solution mentioned in Example 3. At an NC0-value of 14.5%, the re?ction mixture w~s cooled to 60C and the reaction was Mo-2771 ~775 termin~ted by the addition of 0.~1 ml of phosphorus trichloride. The NCO-value settled at a constant 14.1~.
Aftel- heating to 80C, 88.6 parts by weight (0.14 mo]e) of a propoxylated adduct of 2-butene-1,4-diol and NaHSO3 (molecular weight 430, 70% in N-methvl pvrrolidone) and 3.5 parts by weight (0.05 mole) of n-butanol were added, after which the reaction mixture waC diluted with 100 parts by wei~ht of acetone a~d reacted to an NCO-value of 0%. The acetone was then distilled in vacuo and the solid ground to a powder.
The solid obtained had a carbodiimide group (-N=C=N-) content of 8% bv weight, based on solids, and an S03-ion content of 88 milliequivalents per 100 g of solids. The product contained on average 14.1 carbo-diimide units per mo]ecule.

174 parts by weight (1.0 mole) of 2,4-tolylene diisocyanate were dissolved in 200 parts bv weight of methyl glvcol acetate and 0.05 parts by weight of a technical mix~ure of 1-methyl-1-phospha-2-cyclopentene-l-oxide and l-methyl-l-phospha-3-cyclopentene-1-oxide were added to the resulting soluticn at room tempera-ture, followed bv heating to 80C. The degree of carbo-d,imidization was foll~wed bv the evolution of CO2 and from the reduction in the NCO-content. At an NCO-content of 6.57%, the reaction mixture was cooled to 50C and the reaction was terminated by adding 0.1 part by weight of phosphorus trichloride. After another 30 minutes, the NCO-content settled at a constant value.
Analysis of the reaction product:
NCO-value: 6.35%
NCN-units pe~ molecule (average value): 2.87 The reaction mixture obtained was diluted with 300 parts by weight of methyl glycol acetate and 83.54 Mo-2771 ,.2~775 parts by weight (0.136 mole) of a propoxylated adduct of 2-butene-],4-diol and NaHSO3 (MW 430, 70% in toluene) and, after lO minutes, 18.1 parts by weight (0.244 mole) O r n-butanol were added at 80C to the reaction mixture which was then reacted to an NCO-value of 0~. A
solution was obtained which had a carbodiimide group (-N=C=N-) content of 12.5~, based on solids, and an SO3B-ion content of 63 milliequivalents per 100 g of snlids. The product contained on average 6.1 carbo-diimide units per molecule.EYIMPL~ 10 174 parts by weight (1.0 mole) of 2,4-tolvlene diisocvanate were dissolved in 200 parts by weight of acetone an~, after the addition at room temperature of 0.1 parts by weight of a technical mixture of l-methyl-l-phospha-2-cyclopentene-1-oxide and l-methyl-l-phospha-3-cyclopentene-1-oxide, the resulting solution was heated to 80C. The degree of carbodiimidization was followed by the evolution of CO2 and from the reduction in the NCO-content. At an NCO-content of 6.6%, the reaction mixture was cooled to 60C and the reaction was ter~inated by the addition of O .2 part by weight of phosphorus trichloride. After another 30 minutes, the NCO-content settled at a constant value.
Analysis of the reaction product:
NCO-va]ue: ~.38%
NCN-units per molecule (average value): 2.85 After the addition at 80C of 90.3 parts by weight (0.21 mole) of a propoxylated adduct of 2-butene diol and Na~SO3 (molecular weight 430, 70% i~ toluene) a~d, after 10 minutes, 7.31 parts by weight (0.099 mole) of n-butanol were added at 80C to the reaction mixture which was then reacted to an NCO-value of 0~. 557 parts bv weight of water were then added and the acetone was Mo-2771 lZ7~

distilled off. An aqueous solution was obtained which had a solids content of 32.7%, a carbodiimide group (-N-C=N-) content of 11.7%, based on solids, and an So3 -ion content of 88 milliequivalents per 100 g of solids. The product contained on average 15.1 carbodiimide units per molecule.
The performance tests summarized in the following Table were intended to demonstrate the mode of operation of the additives according to the invention.
For the performance tests, the additives containing carbodiimide groups were reacted with standard commercial dispersions containing carboxyl groups or potential carboxyl groups (carboxylate groups containing volatile triethylammonium counter-ions). The following dispersions were tested as representative of their class: Dispersion A: Euderm* Grund 25 A (a product of Bayer AG), an aqueous acrylate dispersion having a dry matter content of 40% and a carboxyl group content of 136 milliequivalents per 100 g of solids. Dispersion B:
Euderm* Resin 50 B (a product of Bayer AG), an aqueous polybutadiene dispersion having a dry matter content of 40% and a carboxyl group content of 91 milliequivalents per lOQ g of solids. Dispersion C: Bayderm* Finish 60 UD (a product of Bayer AG), an aqueous polyurethane dispersion having a dry matter content of 40% and a carboxylate group (volatile triethylammonium counter-ions) content of 29 milliequivalents per 100 g of solids.
The dispersions were stirred with the quantities indicated in the following Table of the additives according to the invention corresponding to Examples 1, 5 or 10 above and films were drawn from the mixtures onto a glass plate using a 1000 ~ doctor. The films were dried at the particular temperatures indicated and * Trademark Mo-2771 ~1 . , ,;~ .

then tested for tensile strength, breaking elongation and 1007~-modulus. To test their wet strength, the films were stored in water for 24 hours before the measure-ments and measured im~ediatelv afterwards without redrving. The results are shown in the following Table, in which tensile strength is expressed in MPa, breaking elongation in %, 100~-modulus in MPa, drving tempera-tures in C and drying time in minutes. The quantit~7 of additive used is expressed in % of the so~ution of the particular example, based on the dispersion used.

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Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made thereir by those skilled in thP art without departing from the spirit and scope of the invention except as it may be limited by the claims.

Mo-2771

Claims (5)

The embodiments of the invention in which exclusive property or privilege is claimed are defined as follows:

1. An isocyanate derivative which does not contain free isocyanate groups and contains i) a content of carbodiimide groups, -N=C=N-, of about 2 to 30% by weight, ii) on a statistical average at least about 0.8 carbodiimide groups per molecule, iii) about 5 to 200 milliequivalents per 100 g of solids of chemically incorporated sulfonate groups and iv) 0 to about 25%, based on solids, of chemically incorporated ethylene oxide units, -CH2-CH2-O-, in polyether chains.

2. The isocyanate derivatives of Claim 1 which contains i) about 5 to 15% by weight of aromatically-bound carbodiimide groups, and iii) about 5 to 120 milliequivalents per 100 g of solids of chemically incorporated sulfonate groups.

3. A process for producing the isocyanate derivative of Claim 1 which comprises partially carbodiimidizing the isocyanate groups of an organic polyisocyanate or mixture of organic poly- and mono-isocyanates a) having an average NCO functionality of about 1.3 to 2.5 and subsequently reacting the remaining free isocyanate groups present in the carbodiimidization product with mono- and/or polyfunctional compounds containing isocyanate-reactive groups b) while maintaining an equivalent ratio such that there is at least one isocyanate-reactive group for every isocyanate Mo-2771 group, characterized in that a compound containing chemically incorporated sulfonate groups or groups convertible into sulfonate groups by neutralization reaction is used as at least a portion of component b), any groups convertible into sulfonate groups still present on completion of the reaction being completely or partly converted into sulfonate groups by a neutralization reaction and wherein the type and quantitative ratios between the reactants used, the degree of carbodiimidization and the degree of neutralization are selected in such a way that the end products have the contents of carbodiimide and sulfonate groups defined in Claim 1.

4, The process of Claim 3 wherein a compound containing ethylene oxide units incorporated in a polyether chain is used as synthesis component a) and/or b) in a quantity such that said isocyanate derivative contains a positive amount of up to about 25% of said ethylene oxide units.

5. A composition which comprises the isocyanate derivative of Claim 1 and an aqueous solution or dispersion of plastics containing carboxyl groups and/or groups convertible into carboxyl groups.

Mo-2771