US3488324A - Polyureas prepared from diisocyanates of carboxylic acid esters - Google Patents

Description

United States Patent rm. (:1. C08g 22/02 US. Cl. 260-775 3 Claims ABSTRACT OF THE DISCLOSURE Polyureas are prepared by reacting aliphatic diisocyanates of monoand dicarboxylic acid esters with hexamethylene diamine. The polyureas are useful in the shrinkproofin g of wool.

This is a division of application Ser. No. 314,613, filed Oct. 8, 1963 now US. Patent No. 3,357,785 issued Dec. 12, 1967.

This invention relates to the treatment of fibers and textile materials made from them. More particularly it relates to a method for shrinkproofing wool utilizing aliphatic diisocyanates of carboxylic and dicarboxylic acid esters, novel compositions containing the same, and novel products obtained thereby.

There are at least two mechanisms by which the shrinkage of wool may occur. The first of these is known as relaxation shrinkage and occurs when wool is treated with water or other chemicals. The art has attempted to solve the relaxation shrinkage problem by submitting wool to preshrinking wherein the material is allowed to encounter the environment which it would normally encounter during use and thereby be preshrunk before being put into actual use. It is theorized that this shrinking is due to a change in the internal structure of the wool fibers. Another important shrinkage phenomenon, designated felting shrinkage, occurs in consequence of the physical structure of wool fibers. Wool fibers, which are normally clad with scales, will shrink when friction is applied to the wetted wool. The fibers are apparently aligned in random directions and the movement induced in these fibers tends, by a mechanism involving differential friction, to shrink the material. The art has attempted to control felting shrinkage mainly by three techniques. Two of these, the oxidative and hydrolytic methods, involve treating the wool chemically with such materials as hypochlorite or chlorine in the first case, or with proteolytic enzymes such as trypsin and papain in the second. These two processes both suffer the disadvantage of degrading the wool to a point where, in order to achieve effective shrinkproofing, the material is consequently weakened in strength. Both of these methods alter the scale formation on the Wool fibers.

Another method which has been directed toward the control of felting shrinkage is the so-called polymer deposition method. This involves depositing upon the wool fibers a polymer which tends to decrease the shrinkage of the wool when the material is subjected to a normally shrinking environment. Heretofore, the conventional polymer deposition techniques have not been entirely satisfactory, all suffering from one or more disadvantages which seriously limit their commercial acceptance. For example, some polymer systems currently available to the art require the use of large amounts of solvents for the deposition of the polymer. This is a very serious drawback to the wool processor who is generally not equipped to handle solvents both from the standpoints of safety and economy. Another disadvantage attending the polymer deposition process is the relatively large amounts of polymer required to be deposited. This too, as can be readily appreciated, presents an economic barrier to the wool processor. Further, conventional polymer deposition techniques tend to stiffen and harshen the wool such that the material does not conform aesthetically to a desirable standard.

When the disadvantages of the prior processes are considered it is apparent that it would be extremely desirable to have available a process for shrinkproofing wool which does not require the use of organic solvents and large amounts of polymer deposition and which yields a wool which is not harsh to the touch or stiffened to any appreciable extent.

It is accordingly an object of this invention to provide a process for shrinkproofing wool which does not require the use of organic solvents.

It is a further object of the invention to provide novel compositions useful in shrinkproofing wool.

Yet another object of the invention is to provide a process for shrinkproofing wool whereby the wool so treated is not harshened to any appreciable extent.

It is still a further object of the invention to provide a process for shrinkproofing wool by the in situ formation and deposition of a polyurea which does not tend to discolor upon prolonged exposure to light.

These and further objects will become more apparent when full consideration is given to the following detailed disclosure.

In accordance with the present invention it has been discovered that wool may be very effectively shrinkproofed by the in situ formation thereon of a polyurea formed from a water dispersible diamine and a member of a particular class of diisocyanates. The invention contemplates novel processes for forming the novel polyurea, novel diisocyanate compositions used in the novel processes and novel shrinkproofed articles obtained thereby. The process involves serially impregnating wool With the diisocyanate and the diamine, not necessarily, but preferably, in that order. The diamine coming into con tact with the diisocyanate, reacts therewith forming the polyurea polymer as a coating on the wool fibers, though residual amino groups of the wool also co-react, yielding a grafted polymer structure.

It is an important feature of the invention that the formation of the polyurea does not involve the use of an organic solvent but rather uses an aqueous system for the application to the wool fibers of the reactants which form the polyurea. In this regard, it is critical that the diisocyanate be supplied to the wool in the form of an aqueous emulsion and the diamine in the form of an aqueous dispersion. As used herein, dispersion is meant to include solutions.

The diisocyanates contemplated for use in this invention are diisocyanate substituted aliphatic monocarboxylic acid esters or dicarboxylic acid esters of the following structure:

either unsubstituted or substituted with halogen radicals,

R is a lower alkylene or a lower alkylidene radical, R, can be either hydrogen, or the radical Typical of the diisocyanates represented by the foregoing formula are: the esters of 2,6-diisocyanato caproic acid (lysine diisocyanato) such as the methyl, ethyl, propyl, butyl, octyl, dodecyl, stearyl, methoxymethyl, 8- methoxyethyl, -ethoxypropyl, phenyl, benzyl, o-tolyl, o- (2-chlorotolyl), 2-bromoethyl, 1,2-dichloropropyl, 2,3- dichloropropyl, and isopropyl esters; the esters of 2,5-diisocyanato valeric acid (ornithine diisocyanate) such as ethyl, propyl, butyl, hexyl, octyl, dodecyl, stearyl, ethoxymethyl, fl-ethoxyethyl, phenyl, benzyl, o-tolyl, o-(2-chlorotolyl), 2-chloropropyl, 2,3-dichloropropyl and isopropyl esters; the diesters of 2,4-diisocyanato glutaric acid, 2,5- diisocyanato adipic acid, 2,6-diisocyanato pimelic acid, 2,7-diisocyanato suberic acid, 2,9-diisocyanato sebacic acid such as the dimethyl, diethyl, dipropyl, dibutyl, dioctyl, distearyl, diphenyl, dibenzyl, di(o-tolyl), di(o-(2-chlorotolyl)), di(2-chloropropyl), di(2,3-dichloropropyl), and diisopropyl diesters and mixed diesters such as methylpropyl diesters, phenyl-octyl diesters, and benzyl-stearyl diesters. The diisocyanates may be either the levo rotatory forms or the dextro rotatory forms, racemates or mixtures thereof. The diisocyanates preferred for use are the methyl and octyl esters of 2,6-diisocyanato caproic acid and most preferably the octyl ester.

The diamines contemplated for use in the invention are the water dispersible diamines or water dispersible salts of water insoluble diamines. In general, any diamine conforming to the above characteristics will be suitable but it is preferred to use diamines such as hexamethylenediamine; alkyl esters of lysine or ornithine in their water soluble dihydrohalide salt form such as n-octyl-L-lysinate dihydrochloride or n-hexyl ornithinate dihydrochloride; tetramethylene diamine, trimethylene diamine; piperazine, methyl and dimethylpiperazine; a,w-diamino polypropylene oxide; mixtures of the above; and the like. Most preferred among the foregoing is hexamethylenediamine.

Before embarking upon a discussion of the nature and characteristics of the diisocyanate emulsion and diamine dispersion, for purposes of clarity of presentation, the following, which is a description of the general mode of carrying out the process, is presented. In general, the wool is first impregnated with the diisocyanate emulsion so as to provide throughout the wool an amount of diisocyanate. The impregnated wool is then removed from the aqueous emulsion of the diisocyanate and pressed between rollers so as to remove excess moisture and materials. The thus obtained material is then introduced into the diamine dispersion, therein to come in contact with the diamine itself. The reaction between the diamine and the diisocyanate is very rapid at room temperature with the consequent formation of the polyurea corresponding to the diamine and diisocyanate.

After the polymerization reaction is complete the resulting woolen material is wrung to recover unreacted diamine or diisocyanate as the case may be, and the impregnated piece then washed to remove any excess materials such as free polymer or any other diamine or diisocyanate not expressed in the wringing stage. The material is then ready for processing as desired, such as drying, dying, and the like.

In general, for effective shrinkproofing, it is desired to have on the wool and available for conversion to the polyurea between 0.1 and 10% by weight of the diisocyanate and preferably from 0.5 to 4 weight percent based on the weight of wool. This can be obtained by proper adjustment of diisocyanate concentration in the emulsion. This concentration is approximately linearly related to diisocyanate takeup on the wool. In its preferred aspect the wool should take up between -100 weight percent of total emulsion based on weight of wool. Therefore, the concentration of the diisocyanate in the emulsion will be approximately the same as those given in connection with the desired amount to be impregnated, namely from 0.1 to 10% by weight and preferably from 0.5 to 4% by weight of the diisocyanate in water.

With further regard to the diisocyanate emulsion, it is preferred to provide a uniform distribution of diisocyanate through the aqueous system so that the resulting polyurea formed will be uniformly distributed over the surface of the wool and will thus not be heavier in concentration in one place than in another, which dilferences in concentration might by visually apparent and would, therefore, detract from the aesthetic quality of the material. This may be achieved by mechanically dispersing the diisocyanate in the water as by agitation, ultrasonic vibration, the addition of emulsifiers, hereinafter discussed, and the like.

The temperature of the emulsion is not critical and is only a factor to the extent that temperature afiects the chemical stability of the emulsion. In this regard, it will be appreciated that since isocyanate groups react with water, there will be a finite time available to a processor during which a substantial amount of diisocyanate remains unreacted. This time will vary depending on the particular diisocyanate employed. For the preferred diisocyanate herein, octyl 2,6-diisocyanato caproate, the time is sufficiently long so that the emulsion is conveniently handled within 12 hours after its preparation. Operating within this time, good results are obtained when the emulsion bath temperature is between room temperature and about 40 C. For diisocyanates having a higher rate of reactivity, such as methyl 2,6-diisocyanato caproate, lower bath temperatures are conveniently employed to retard the reactivity and allow the processor convenient time in which to impregnate the wool. Temperatures of the order of 5 to 15 C. are suitable for this purpose.

With regard to the length of time and the conditions under which the diisocyanate impregnates the wool, contact times in the ester bath are related to the physical state of the wool (fibers, yarn, fabric). Particular consideration is given to the thickness of the weave and its density. In general, the more dense the material the longer the contact time necessary to impregnate the wool with a convenient amount of diisocyanate. In dealing with typical flannel suiting material good results are obtained when the contact time is between 10 and 60 seconds. Shorter contact times of the order of one second or less are suitable for treating yarns and less dense materials, and longer times may be necessary for heavy fabrics.

With respect to the aqueous diamine dispersion it will be appreciated, as indicated previously, that the reaction between the diisocyanate and the diamine is very rapid and occurs quite fast at room temperature. For this reason the concentration of the diamine in the aqueous solution thereof is not critical. Since a one-to-one molar ratio of diamine to diisocyanate is required by the stoichiometry it is, of course, preferred to supply in the aqueous solution a sufiicient amount of diamine to react with all the diisocyanate present in the wool. For reasons of economy it is not desired to have an amount of diamine less than the stoichiometrically required amount. Hence the concentration of the diamine may be any convenient level consistent with these aims. The temperature and the contact time are not at all critical. Maintaining the bath at a temperature of about room temperature to about 40 C. gives satisfactory results and as indicated above the reaction rate is very rapid. Hence, the contact time is of no criticality. Although the discussion here has been provided with respect to carrying out the reaction in a batchwise operation it will be understood that the process as a whole is particularly amenable to continuous operation and this is therefore the preferred mode of carrying it out.

Further, although the above description is directed toward carrying out the process by first impregnating with diisocyanate followed by the polymerization reaction with the diamine, the process is not to be limited to such a sequence of operations. Indeed, the impregnation may first be with the diamine dispersion, followed by polymerization through the use of the diisocyanate emulsion. When this order is carried out it will be appreciated by those skilled in the art that a simple, straight-forward calculation will yield the amount of diamine present in the first solution in order to obtain a wool article desirably having between 0.1 and weight percent of polyurea impregnated thereon. Thus, by working back from the amount of polyurea desired to be put on, one may obtain the concentration of the diamine starting solution. The two bath process, in either order, is referred to as a serial treatment herein.

In preparing the emulsion of the diisocyanate material the process is operative when the diisocyanate is uniformly distributed in the water system without the aid of any additives. However, when this is done the ensuing operations should be carried out hastily so as to avoid settling of the emulsion in the bath. As indicated previously, an emulsion of this type might not give uniform polymer deposition upon subsequent reaction with diamine. For this reason it is preferred to add an emulsifying agent to aid in the emulsification of the diisocyanate in the water. In general, the nonionic, anionic, and cationic emulsifiers are suitable and, in fact, any

available emulsifier which does not contain primary and' secondary amino groups is suitable. That is to say, the particular emulsifier is not critical and will vary depending upon the particular diisocyanate employed as a starting material. The goal is so to obtain a good emulsion which is non-settling within a convenient operating time and one which gives good dispersion of particles throughout the medium. Hence any emulsifier which does this will be suitable. Thus it is even possible to use an emulsifier which may not be inert with respect to the diisocyanate but is effective to form a good emulsion, if the rate of reaction between the emulsifier and the diisocyanate is not too rapid. In this regard, it will be remembered that the diisocyanate, being in contact with water, itself undergoes some reaction with the water. This is not detrimental to the process provided that the impregnation be carried out in such time as will provide within the wool lattice a convenient amount of unreacted diisocyanate. With regard to the amount of emulsifier used, it is convenient to use, for the preferred emulsifiers described hereinafter, about 10-15% by weight based on the diisocyanate. For other materials, the total amount of emulsifier should be enough to produce the desirable emulsion and yet still be consistent with good reaction economics. The emulsifier may be added to, mixed, or blended with the diisocyanate prior to mixing with water. Such compositions of emulsifier and diisocyanate are novel.

In general, suitable emulsifying agents are as follows: Sodium lauryl sulfate, Ivory soap, sodium-N-methyl-N- oleoyl taurate (available under the trade name Igepon T-77), octyl phenoxy polyethoXy ethanol (available under the trade name Triton X-), isooetyl phenyl polyethoxy ethanol (available under the trade name Triton X-45). Also useful are various other emulsifiers available under the Triton trade name such as Triton CF-2 1, Triton X- (octyl phenoxy polyethoxy ethanol), Triton X-405 (octylphenoxy polyethodyethanol), Triton CF32, and Triton X-l5 (octyl phenoxy polyethoxyethanol), many of which are alkyl aryl polyethers; those available under the trade name Tergitol from such as Tergitol NP l-X, Tergitol NP-27, Tergitol NPX, and Tergitol NP-35, all of which are nonyl phenyl polyethylene glycol ethers.

In addition to the diisocyanates above, which are preferred, other diisocyanates and their adducts may also be used. For example, where some degree of yellowing can be tolerated, tolylene diisocyanate, phenylene diisocyanate or methylene bis-phenyl isocyanate may be emulsified and used in the serial treatment with a diamine. With these more reactive isocyanates it is necessary to maintain the emulsion bath at low temperatures (5-10 C. preferred) and to work with a short hold-up time to avoid premature polymer formation. Hexamethylene diisocyanate, which is a hazardous substance to handle, is best converted to an isocyanate terminated adduct (with butylene glycol, hexamethylene glycol and the like) before emulsification. Control of polymer rigidity is done via the choice of adduct or choice of diamine.

In addition to their efiicacy as shrinkproofing treatments, all the above may find use in other textile finishing operations. Thus, by proper choice of monomers, useful and more or less permanent antistatic, water resistance, or wash-and-wear characteristics may be introduced.

The following examples are given for purposes of illustration only and are not to be considered as limiting the invention. In each of the following examples, unless otherwise indicated, the following test method is employed: A wool cloth is dipped into bath (1). After remaining in the bath for a period of time the cloth is removed and passed twice through a hand-operated wringer to remove excess material. It is then immersed in bath (2) and again passed twice through a wringer, The contact time for each of the above immersions may vary from 15 to 30 to 60 seconds without any noticable effect in the shrink-proofing obtained. The cloth is then rinsed with water to remove unreacted monomers, emulsifier and unbound polymer and allowed to dry.

The test for shrinkage involves washing three to six pieces of wool measuring about 4 to 6 inches in a bowl of 0.1% solution of Triton X-l00 (octyl phenoxy polyethoxy ethanol), at 40 C. for 20 minutes. The samples are oven dried at 60 C. to constant weight. In each washing there is always at least one untreated piece included to serve as a control. Each of the pieces is measured before treatment and after washing-drying for calculating of area shrinkage.

EXAMPLE 1 Shrinkage 17% (control 40%) 7 EXAMPLE 3 Octyl-2,6-diisocyanato caproate g 4 Sodium lauryl sulfate g .25 Water ml 250 Hexamethylenediamine g Water ml 250 Shrinkage 6% (control 43%) EXAMPLE 4 Octyl-2,6-diisocyanato caproate g 4 Triton X-15 (octyl phenoxy polyethoxy ethanol) g .5 Water ml 250 n-Octyl-L-lysinate dihydrochloride g Sodium carbonate g 10 Water ml 250 Shrinkage 16% (control 42%) EXAMPLE 5 Octyl-2,6-diisocyanato caproate g 2 Triton X- (Octyl phenoxy polyethoxy ethanol (or Triton CF-2l (alkyl aryl polyether)) g .25 Water ml 250 n-Octyl-L-lysinate dihydrochloride g 5 Sodium carbonate g 5 Water l 250 Shrinkage 25% (control 41%) EXAMPLE 6 Methyl-2,6-diisocyanato caproate g 2 Triton X-15 (octyl phenoxy polyethoxy ethanol) g .25 Water ml 250 (2) Hexamethylenedlamine g 5 Water ml 250 Shrinkage 3% (control 34%) EXAMPLE 7 Methyl-2,6-diisocyanato caproate g 2 Triton X-15 (octyl phenoxy polyethoxy ethanol) g .25 Water ml 250 n-Octyl-L-lysinate dihydrochloride g 5 Sodium carbonate g 5 Water ml- 250 Shrinkage (control 38%) EXAMPLES 8 THROUGH 15 The following examples demonstrate the effect of various emulsifiers on the process. In the following examples 2 g. of octyl-2,6-diisocyanato caproate in 250 ml. water along with 0.25 g. of the emulsifier listed are used as bath 1. The second solution into which the wool is dipped according to the procedure of Examples 1-7 consists of 5 g. of hexamethylenediamine in 250 ml. water. The following table demonstrates the shrinkage of the treated pieces of wool.

TABLE 1 Shrinkage, percent Ex. Emulsifier Treated Centre 8-.-" Aquarex D (sodium sulfates of higher fatty alcohols) 30 40 9.---. Ivory soap 15 42 10.-.- Triton X-15 (oetyl phenoxy polyethoxy ethanol) 5 41 11- Sodium lauryl sulfate 13 38 12...- Triton X-45 (Octyl phenoxy polyethoxy ethanol) 34 39 13 Triton CIT-32 (amine polyglycol condensate)- 15 38 14.--- Triton X- (octyl phenoxy polyethoxy ethanol) 30 38 15 Triton CF-21 (alkyl aryl polyether) 5 41 EXAMPLE 16 This example shows the shrinkproofing of wool using an emulsion of octyl-2,6-diisocyanato caproate in water without the aid of an emulsifier.

System (1) below is prepared by rapid agitation in a Waring Blendor, and used immediately after preparation as the first bath in treatment of wool. System (2) is used as the second bath. Results are shown.

Octyl-2,6-diisocyanato caproate g 2 Water ml 250 Hexamethylenediamine g 5 Water ml 250 Shrinkage 6% (control 44% Wool cloth showed some streaks of resin.

EXAMPLE 17 Following the procedure of Example 16, the following bath components are employed. Shrinkage results are shown.

Octyl-2,6-diisocyanato caproate is mixed with the various emulsifiers shown in Table 2 below such that the emulsifier constitutes 10% by weight of the total mixture. The original isocyanate content is measured and compared with the final isocyanate content of the mixture after it has been allowed to stand for 76 days.

TABLE 2 Isoeyanate Content in Weight Percent Time in Emulsifier Initial Final Days Sodium lauryl sulfate 24. 4 22. 0 76 Triton (IF-21 (alkyl aryl polyether) 24. 4 21. 9 76 Triton CF-32 (amine polyglycol condensate) 24. 4 20. 2 76 Tergitol NP-IX (nonyl phenyl polyethylene glycol ether) 24. 4 22. 1 76 Tergitol NP-27 (nonyl phenyl polyethylene glycol ether) 24. 4 21. 7 76 Tergitol NPX (nonyl phenyl polyethylene glycol ether) 24. 4 22. 0 76 Tergitol NP-35 (nonyl phenyl polyethylene glycol ether) 24. 4 20. 7 76 Eighty-three day-s after initial formulation, each of the above mixtures is separately added to water (0.5 g. of mixture, 50 g. water) and good emulsions are ob tained.

The following examples are intended to be illustrative of the preparation of the diisocyanato esters used in the present invention.

9 EXAMPLE 19 2,6-diisocyanato methyl caproate 250 g. of lysine monohydrochloride suspended in 2500 ml. of absolute methanol is dissolved by passing into the stirred suspension dry hydrogen chloride. The reaction temperature immediately goes up to 47 C. and in 10 minutes all the solids are dissolved. The gas is passed in for five minutes longer. The reaction mass is then permitted to cool slowly to room temperature with stirring. Crystals start to form in 2.5 hours. The reaction mass is stirred for a period of hours at a temperature of C. The product is precipitated by adding 1.5 liters of diethyl ether over a period of 15 minutes. After one hour of stirring, the product is isolated by filtration and washing with three parts of ether dissolved in two parts of methanol, followed by a diethyl ether wash. The product lysine dihydrochloride methyl ester is dried to constant weight at 65 C. in a vacuum oven.

The lysine methyl ester dihydrochloride is finely ground in a mortar and 186 grams is suspended in 2100 ml. of freshly dried and redistilled o-dichlorobenzene in a 3-nick flask.

Phosgene is passed into the reaction vessel at a rapid rate while raising the temperature of the suspension to ISO-155 C. As the reaction proceeds the solution becomes clearer and darker. Hydrogen chloride evolution is indicated -'by fuming from the condenser as it hits the moist atmosphere. After twelve hours, no more hydrogen chloride evolves. Phosgene is passed in for one more hour and nitrogen is then bubbled through the reaction vessel as the solution temperature drops to 25 C. to remove residual phosgene and hydrogen chloride. The remaining solids are removed by filtration and washed. The filtrate is then distilled under reduced pressure. 0 Dichlorobenzene, the solvent, is distilled at 44 C. and 2 mm. pressure. The product, 2,6-diisocyanato methyl caproate, is distilled at 123 C., at 0.45 mm. pressure. A clear, colorless liquid product is obtained having a refractive index of 1.4565 at 245 C.

In an analogous manner, the ethyl, propyl, butyl, or pentyl esters of 2,6-diisocyanato caproic acid are prepared by substituting equivalent amounts of ethanol, propanol, butanol or pentanol for methanol in the foregoing procedure.

Similarly, when equivalent amounts of the monohydrochloride of 2,5-diamine valeric acid are substituted for lysine monohydrochloride and equivalent amounts of methanol, ethanol, propanol, butanol or pentanol are employed as the alcohol in the foregoing procedure, the corresponding methyl, ethyl, propyl, butyl or pentyl ester of 2,5-diisocyanato valeric acid is obtained.

EXAMPLE 2O 2,6-diisocyanato-n-octyl caproate 18.2 g. (0.1 mole) of l-lysine monohydrochloride is suspended in 140 ml. of n-octanol containing 0.24 mole of p-toluenesulfonic acid. The mixture is heated until Water and octanol begin to distill and the reaction temperature is then maintained at 120-130 C. by addition of n-octanol. After 240 ml. of n-octanol are added and removed over a two hour period, the residual alcohol is removed by vacuum stripping. The waxy product, the di-p-toluenesulfonate salt of 2,6-diamino-n-octyl caproate, is recrystallized from a mixture of ethanol and diethyl ether.

A solution of 73 grams of this product in 150 ml. methanol is adsorbed on a column of 500 ml. of a strongly basic styrene-divinylbenzene anion exchange resin (Dowax 1-X8) which had previously been activated on the hydroxyl cycle with aqueous ammonia, Washed to neutrality, and had its water displaced with methanol. The product is eluted from the column with methanol. The free base ester is not isolated but converted to the dihydrochloride recovered by precipitation with diethyl ether. The dihydrochloride is suspended in 275 ml. of toluene and 0.45 mole of phosgene added at 6070 C. When evolution of HCl ceases, the temperature of the reaction mass is gradually increased to strip out the solvent. The product, 2,6-diisocyanato-n-octyl caproate is recovered by vacuum fractionation, B.P. 137-l42 C. at 0.2 mm.

When the foregoing procedure is repeated using equivalent amounts of hexanol, decanol, dodecanol, or tetradecanol in place of octanol, the corresponding hexyl, decyl, dodecyl, or tetradecyl ester of 2,6-diisocyanato caproic acid is obtained.

Similarly, when the foregoing procedure is repeated using equivalent amounts of the monohydrochloride of 2,5-diamino valeric acid in place of the lysine mono hydrochloride and equivalent amounts of hexanol, octanol, decanol, dodecanol, or tetradecanol are employed as the alcohol, the corresponding hexyl, octyl, decyl, dodecyl or tetradecyl ester of 2,5-diisocyanato valeric acid is obtained.

EXAMPLE 21 2,6-diisocyanato phenyl caproate The acid chloride of lysine dihydrochloride is prepared by passing phosgene through a suspension of lysine dihydrochloride in dioxane for several hours at 50 C. The oily product is added to dimethyl formamide containing the calculated amount of sodium phenoxide to form the phenyl esters of lysine dihydrochloride. This ester is suspended along with a small amount of sodium chloride, in o-dichlorobenzene (0.1 mole in 200 ml.) and phosgenated with gaseous phosgene at C. The resulting carbamyl chloride is decomposed at C. and the solution is filtered, concentrated, treated with absorbent carbon, and the solvent removed to yield yellow 2,6-diisocyanato phenyl caproate which was then purified by molecular distillation.

When the foregoing procedure is repeated using equivalent amounts of the sodium salt of either o-cresol or 2,4,6-trichlorophenol in place of the sodium phenoxide, the o-tolyl or l,3,5-trichlorophenyl ester of 2,6-diisocyanato caproic acid is obtained respectively.

Similarly, when equivalent amounts of ornithine dihydrochloride are substituted for the lysine dihydrochloride in the above procedure, the corresponding 2,5-diisocyanato valeric acid esters are obtained.

It will be apparent to those skilled in the art that a wide variety of combinations and variations may be employed in preparing the compositions of the present invention without departing from the spirit and scope of the invention. All such modifications, changes and variations, departing from the above description are intended to be encompassed within the scope of the appended claims.

What is claimed is:

1. The reaction product of hexamethylenediamine and a diisocyanate of the formula:

wherein R is selected from the group consisting of alkyl, alkoxy alkyl, aryl, alkaryl, aralkyl, and halogenated derivatives thereof, R is selected from the group consisting of lower alkylene or lower alkylidene and R is selected from the group consisting of hydrogen and the radical 2. The reaction product of claim 1 wherein the diisocyanate is octyl-2,6-diisocyanato caproate.

1 1 1 2 3. The reaction product of claim 1 wherein the di- 822,861 11/1959 Great Britain. isocyanate is methyl-2,6-diisocyanato caproate. 858,612 1/1961 Great Britain.

References Cited OTHER REFERENCES UNITED STATES PATENTS 5 239,456, published on Apr. 20, 1943. 2,292,443 8/1942 Hanford 26077.5 2,768,154 10/1956 Unruh et a1. 260-73 DONALD E. CZAIA, Primary Examiner 3,076,788 2/1963 Hoover 260-775 3,281,378 10/1966 Garber et a1. 260 2.5 WELSH Assstant Exammer 3,357,785 12/1967 Garber et a1. 8128 10 CL FOREIGN PATENTS 8128; 260 29.2, 453

79,747 2/ 1952 Norway.

Rinke et a1.: Alien Property Custodian, Ser. No.