NO761657L - - Google Patents

Description

Process for curing polymers, particularly polyurethanes, with amine compounds.

The present invention relates to catalytic hardening and softening

of amine-curable polymers and especially polyurethane polymers using a specific class of compounds together with methylene-dianiline complexes or racemic 2,3-di(4-amino-phenyl)butane complexes with reduced curing times and rather low temperatures for the preparation of polymers with unexpectedly improved strength properties.

Previously, curing of amine-curable polymers or pre-

polymers such as epoxy resins, processable halogen-containing hydrocarbon polymers, and especially isocyanate-terminated polyurethane prepolymers generally involve mixing with an amine curing agent, shaping the resulting mixture into a desired shape, and heating to complete the curing or vulcanization reaction. However, a problem that usually arose during this process was that of prior reaction of the curing agent with the curable polymer during the mixing and shaping operations. This problem was particularly acute with highly reactive systems such as when curing isocyanate-terminated polyurethane prepolymers, which made it necessary to use special mixing devices with a short residence time and selected diamine curing agents with reduced activity, which also usually limited the mechanical properties of the vulcanizates.

The type of frequently used hardener that has won over many

of the above problems are the complexes of methylenedianiline and a salt which, when heated, usually at temperatures above 100°C, released the methylenedianiline from the complex and allowed this to begin the curing of the polymers (US patent no. 3,755,261). Although this

meant an improvement, this type of curing agent still tended to prolong processing times, required unwanted time when removing the molds and thus proved to be uneconomic due to the large number of molds that were needed. The only way to overcome these difficulties was to increase the curing temperature, which of course resulted in an increase in the curing rate. Elevated curing temperatures, however, caused greater thermal expansion and subsequent shrinkage in the finished object and this often led to stresses and cracks in the product.

In recent times, various hardener complexes such as

e.g. methylene-dianiline has been catalyzed with usually different polar materials as well as hydroxyl-containing compounds. Although these various compounds usually improve the curing time and lower the curing temperature, these compounds bring about several undesirable aspects. E.g. did some connections tend to

hardening too quickly and a uniform hardening of the shaped object was thus made difficult. Another problem was that they tended to act as solvents in connection with apparatus for automatic feeding and mixing and actually dissolved some gaskets in the equipment. Outgassing was a further problem in that the catalyzed compounds tended to harden the polymers before the gas had had time to escape from the molded article. Other catalysts further tended to produce a

viscous polymer which, in addition to the degassing problems, required a far too long time for filling into a mold. On the other hand, many of the compounds produced a mixture with too low a viscosity and created problems with the supply of the exact quantities of the various components due to failure of the supply pumps themselves. From the point of view of mechanical properties, none of the catalysts produced improved ones.

It is an object of the present compound to provide "plasticizers" for a methylene-dianiline complex or a racemic 2,3,-di(4-aminophenyl)butane complex used as curing agents in the curing of amine-curable polymers or prepolymers, in particular polyurethane polymers, as the plasticizer acts as a catalyst and increases the curing speed and lowers the initial curing temperature, which further reduces the time for removing the mold and the costs of the shaping operation.

The softener for the hardener when curing amine curables

polymers or prepolymers cause the polymerization to take place quickly at fairly low temperatures and at least at temperatures lower than what is normally otherwise possible.

The plasticizer for the hardener results in improved elastomer strength, allows the delivery of components in precise quantities and is not harmful to the seals in the equipment used. The softener for the hardener further allows for even curing, appropriate time for removal from the molds, and eliminates outgassing problems.

The plasticizer for the hardener will produce a suitable molded blank for the tire stems when manufacturing car tires, as the tire stems will have greater elasticity and durability.

These and other purposes of the invention will be apparent from the subsequent presentation which describes in detail various exemplary and preferred embodiments of the invention.

Typically, a catalyst-cured polymer comprises 100 parts of an amine-curable polymer or prepolymer selected from the group consisting of urethanes containing free isocyanate groups, epoxy resins, polymers containing acid halide and halogen-formate groups, and polymers containing acid anhydride groups which, upon reaction with diamines, give amide-acid linkages , from 0.8 to 1.2 equivalents of a curing agent based on the free active groups in the aforementioned amine curable polymers or prepolymers, the curing agent being selected from the group consisting of a complex of 4,4'-methylenedianiline and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, sodium nitrate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate and sodium cyanide, and a complex of racemic 2,3,-di(4-aminophenyl)butane and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium chloride, rubidium bromine d rubidium iodide, cesium chloride, cesium bromide and cesium iodide, the ratio between dianiline and the said butane and the said complex being approximately 3 mol per moles and from about 1.0 parts to -15.0 parts

of an ester of formula

wherein R i is a polyglycol

having from 2 to 5 carbon atoms and R is an aliphatic compound having from 4' to 9 carbon atoms, and X is 1 or 2 and Y is an integer from 1 to 5.

Further, a catalyst cured polymer composition comprises 100 parts by weight of an amine curable polymer or prepolymer selected from the group consisting of halogen-containing hydrocarbon polymers, chlorosulfonated polymers and organo-polysiloxanes and from about 0.0005

to 0.05 equivalents of a curing agent based on the active groups in the said amine curable polymer wherein the curing agent is the same as mentioned above, the composition also containing from about 1.0 to 15.0 parts of the said ester.

It has been found that the use of various specific ester plasticizers in combination with a curing agent used for curing amine curable polymers or prepolymers usually results in higher cure rates, reduced cure temperatures, or both, along with good demolding times, elimination of outgassing problems and unexpected improvement in mechanical durability properties, particularly with regard to cast urethane elastomers with preferred application as tire stem blanks.

A specific and preferred curing agent is a complex of 4,4'-methylene-dianiline (MDA) and a salt. The preparation of the specific curing agent complex is indicated in US Patent 3,755,261

and which specifically explains the formation of the various complexes of 4,4'-methylene-dianiline and a salt. In general, the complexes used as curing agents for amine curable polymers comprise the reaction products of 4,4'-methylene-dianiline with the following salts in a ratio of about 3 mol methylene-dianiline to about 1 mol salt, of the type sodium chloride, sodium bromide, sodium iodide , sodium nitrate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate and sodium cyanide. The sodium chloride is the salt which is decidedly preferred.

Another complex that can be used as a curing agent is the reaction products of racemic 2,3-di(4-aminophenyl)butane with any of the following salts in a ratio of about 3 moles of diamine to about 1 mole of saltj sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium chloride, rubidium-bromi.d, rubidium iodide, cesium chloride, cesium bromide, and cesium iodide.

The most preferred salt is sodium chloride. The production of the curing agent is covered in detail in US Patent 3,755,261.

Use of the preferred curing agent (MDA) or butane complex in curing amine-curable prepolymers or polymers by heating to a temperature of about 100°C causes methylene-dianiline to be released from the complex and cures the polymers or prepolymers in a manner that one imagines is identical to that which takes place when free methylene-dianiline or butane is used as curing agent.

The above complexes can cure many amine curable prepolymers or polymers as indicated in the above-mentioned US Patent 3,755,261 but in general the preferred class of such prepolymers or polymers are the urethanes commonly formed by reaction between a diisocyanate and a glycol or a diol with a molecular weight of generally 400 to 8,000 and preferably from 600 to 3,000. Such urethanes can typically be formed by reacting polyalkylene diols, polyalkylene ether diols, polyester polyols, polybutadiene diols and combinations thereof with an equivalent amount or a small excess of diisocyanates or triisocyanates to form a prepolymer with terminal isocyanate groups. Patents that describe some general types of urethanes are US Pat. Highly preferred specific diols include polypropylene terdiol and polytetramethylene ether diol. Other preferred diols include polyethylene ether diol, polyt-fi-methylene ether diol, polyhexamethylene ether diol and the like.

Other groups of amine curable prepolymers or polymers indicated

in US patent 3,755,261 are epoxy resins, polymers which

contains acid halide groups such as

and halogen

formate groups such as

polymers containing

' acid anhydride groups which by reaction with diamines give amide-acid bonds halogen-containing hydrocarbon polymers such as e.g. chloroprene polymers, chlorinated butyl rubber and chlorinated polyethylene and polypropylene-chlorosulfonated polymers and organo-polysiloxanes.

The specific ester softeners used in it

present invention, in combination with the above-mentioned complex curing agents, have been found to act as accelerators or have a catalytic effect on the curing of the polyurethane as well as the other indicated amine-curable polymers or prepolymers. In addition, it has also been found that when the different polymers

is cured in a heated mold which, in the manufacture of cast blanks for tire stems, usually eliminates problems of outgassing, premature curing, uneven curing, slow feed rate to the mold due to a high viscosity of the mixture, and problems with accurately fed quantities which often due to too low viscosities,

and which are often combined with other catalysts for the above-mentioned complex hardeners..

Based on 100 parts by weight of polymer or prepolymer, it is desirable

with about lj'0 to 15.0 parts of an ester of the indicated type.

A preferred range is from about 2.0 to 10.0 parts. The exact amount of a particular polyglycol will of course vary depending on the particular cure temperature, the particular amine curable polymer and the particular catalyst used.

The esters used have the formula

.Generally can

R 1 can be any polyglycol containing the glycol

from 2 to 5 carbon atoms, and mixtures thereof. X is 1 or 2 and Y

is 1 to 5. X 2 and Y are preferred. Specific examples of polyglycols include tetraethylene glycol, tetrapropylene glycol, tetrabutylene glycol, tetrapentylene glycol, diethylene dipropylene glycol, propylene triethylene glycol and the like. Preferred polyglycol compounds

include tetraethylene glycol and tetrapropylene glycol, with tetraethylene glycol being strongly preferred.

In general, R is an aliphatic compound containing from 4 to 9 carbon atoms and is preferably an alkane. Specific examples include butyl, pentyl, hexyl, heptyl, octyl, nonyl, 2-ethylhexyl and the like, 2-ethylhexyl being preferred. As anqitt above

has a strongly preferred type of ester formula

A highly preferred compound is thus tetraethylene glycol di(2-ethylhexoate). The specific formula is as follows:

Tetraethylene glycol di(2-ethylhexoate) is commercially available as "Flexol 4G0" and is manufactured by Union Carbide. The composition of other polyglycol esters of 2-ethylhexanoic acid are, of course, identical with the exception of the part of the molecule which is located in the parenthesis region. As already indicated, this group of specific plasticizers gives good practical results in the treatment and curing of various amine curable polymers. This relationship is quite surprising as it is clear from the above chemical formula for a typical compound that the plasticizers are not strongly polar and do not contain free hydroxide compounds as with previously used compounds but are high molecular weight esters in which the polar groups are considerably sterically hindered. . -Further preferred compounds are the half-esters, i.e. compounds in which X 1 and Y = 1. Examples include methylene M-butyrate, ethyl M-butyrate, ethyl isobutyrate, ethyl valerate, ethyl caproate, ethyl heptoate, ethyl caprylate, ethyl pelargonate and the like comprising propyl-, butyl- and the amyl derivatives.

The plasticizers are also advantageous in that they usually

has a high boiling point, e.g. 218°C at 5 torr for tetraethylene glycol di(2-ethylhexoate), and thus very little plasticizer is lost during curing in contrast to the more volatile catalysts previously used which tended to cause excessive shrinkage Furthermore, the viscosities of the different plasticizers, e.g. 12 eps at 40°C for tetraethylene glycol di{2-ethylhexoate), are suitable for accurate delivery of the plasticizer component, i.e. without failure of the metering pump,

and when mixed with the amine curable polymers and other components such as e.g. other plasticizers, they will be well miscible and allow short injection times as well as suitable escape times for developed gases. Uneven curing and degassing problems are thereby easily eliminated. Furthermore, the plasticizers do not act as a solvent or break down various rings and seals in the equipment for forming and feeding. Furthermore, the plasticizers are liquid at the desired curing temperatures of from about 80 to 170°C. A preferred cure temperature for most polymer systems including urethanes is from 100 to 140°C with a strongly preferred temperature range of about 115 to 125°C.

When the amine-curable polymer or prepolymer is polyurethane, the amounts of the two above-mentioned curing agent complexes will usually be from about 0.8 to 1.2 equivalents of the diamine in the curing agent to the free isocyanate groups in the polyurethane. A more preferred range is from about 0 .9 to 1.05 equivalents id e-t a ratio- of about 1.025 is preferred. Ratios greater or less than the wide range in manufacturing the most preferred product of cast urethane tire stem blank results in noticeable differences both in the process for

■the hardening of the product as well as its mechanical properties.

The above-mentioned ranges are also applicable to mixtures containing the above-mentioned epoxy resins, polymers containing acid halide groups and halogen-formate groups as well as polymers containing acid anhydride groups which with diamines give anide-acid bonds. I.e. that the amount of hardener

complex such as methylene dianiline and et-salt'", e.g. sodium chloride,

must have the above-mentioned equivalent range based on the number

of free active groups in the polymer or prepolymer which react with the methyl-ene-dianiline.

With respect to the other polymers or prepolymers, i.e

the halogen-containing hydrocarbon polymers, the chlorosulfonated polymers and the organo-polysiloxanes, because they do not usually contain isocyanate groups on the end parts of the chain, only a much smaller equivalence ratio will be needed to cure these compounds, as in cross-linking. Depending on the desired molecular weight of the polymers and the molecular weight of the prepolymers, the amount of amine curing agent can vary within wide limits. Typically, this range extends from about 0.0005 to 0.05 equivalents

of the reactive part of the hardener such as e.g. the diamine to them

r'

active groups contained in the polymer or prepolymer. A preferred range is from 0.0005 to 0.05 equivalents. The amount of ester plasticizer used for the other polymers or prepolymers is usually the same as stated above for the urethane compounds, prepolymers or polymers.

In accordance with well-known techniques in this area of shaping

and curing amine-curable polymers or prepolymers, conventional additives or compounds may be added to the compositions to impart desired properties thereto. The additive raw materials include traditional anti-foaming agents, conventional pigments to give an attractive appearance, conventional foaming agents for foamed articles, and conventional fillers such as e.g. "Hi Sil" and the like. Other additives can of course also be added depending on the desired area of application for the product, such as e.g. flame retardants and the like.

In the production of polyurethanes, it is often desirable to

add conventional plasticizers to increase the elasticity of the object. The addition of such conventional plasticizers is preferred in the manufacture of urethanes, especially for their use as a tire stem blank. Specifically preferred plasticizers used in the manufacture of urethanes include dioctyl phthalate (DOP), diisooctyl phthalate (DIOP), diisodecyl phthalate (DIDP), and dinonyl phthalate (DNP). DO'P - preferred. The use of a conventional plasticizer as well as the ester plasticizers used according to the invention, in addition to providing increased elasticity in the final hardened product, has unexpectedly also been found to provide improved durability as indicated in the following examples I and II. Although the exact reason for this result is not clearly understood, it is believed that the use of a conventional plasticizer together with an ester plasticizer according to the present invention in addition to being an unexpected curing catalyst will produce a synergistic and unexpected result. A suitable range for conventional plasticizers can vary from about 4 to 20

parts per 100 parts amine curable polymer and preferably from about 12 to 17 parts. As the various ester softeners such as e.g. The polyglycol ester of 2-ethylhexanoic acid is completely miscible with the preferred plasticizers such as e.g. DOP and are less volatile than the plasticizers, the total result is one

■ less volatile emollient system so that the degassing problems are reduced and larger quantities of the preferred plasticizer remain in the hardened elastomer system. It has further been found that the use of two plasticizers gives greater elasticity to the cured polymer, particularly at low temperatures. The conventional plasticizer is preferably added as a mixture with the amine hardener.

Light stabilizers can also be used, especially for the production of polyurethanes as hardened cover blanks. An advantageous light stabilizer is "carbon black" in an amount of from about 0.3 to 3.0 parts per 100 parts amine curable polymer. Amounts in excess of three parts tend to form a very viscous polymer mixture which leads to difficulties in rapid or reasonably rapid mold filling and consequently to uneven curing and poor properties. As large particle sizes of "carbon black" have a greater tendency to become one

source of cracking, a fine particle size is preferred.

Typically, particles of no more than 1 micron are preferred. Of course, any conventional "carbon black" that responds1

to this requirement is applied, such as e.g. "REGAL 400R", manufactured by Cabot. Additionally, "carbon black'-' also provides the characteristic

black color for tires which seems to be aesthetically pleasing to the customers.

Other light stabilizers include either conventional inorganic or conventional organic dyes or pigments in an amount of from about 0.3 to 1.5 parts per 100 parts polymer. The dyes can either fully replace "carbon black" or partially replace it. Although "carbon blackM" is generally desirable as opposed to the dyes, nevertheless dyes are often used as they have very small particle size, much less than 1 micron. Specific examples of dyes include "thermoplast NSP", an organic dye sold by American Ugine and "Nigronsine SSB", an organic dye manufactured by American Cyanamide.Of course, other conventional organic or inorganic dyes or pigments can also be used, such as TxO 2 .

The curable prepolymers or polymers according to the invention can be used for many applications, e.g. a polyurethane can be used for shoe soles, wear equipment, roller wheels, car parts and car shock absorbers. As previously indicated, a very important and commercial application lies in the production of tire stem

items that can be applied with conventional sl ite track rubber such as polybutadiene styrene.

Mixtures can be prepared by mixing the polymer or prepolymer' with a hardener complex at ambient or slightly too high temperature, e.g. about 50°C, but below the curing temperature of the complex curing agent which is generally about 90 to 100°C. The various thickening agents, fillers and the like can also be added and mixed in. If the curing agent is the preferred methylene-dianiline complex with sodium chloride, it will usually contain a protective colloid or dispersant such as e.g. lecithin. As lecithin is also a good foam stabilizer, an anti-foam agent such as e.g. Dow Corning Paint Additive 17,

a mixture containing a silicone compound is added. In general, it has been found that if a centrifugal

form, such as when producing a tire stem error,

if the viscosity is low and a high molding speed is used, no antifoam need be added. It is further noted that DOP can be used as a carrier for the MDA hardener and the amount of preferred softeners that are added can thus be reduced to a corresponding degree. In any case, the various esters such as e.g. the various polyglycol esters of 2-ethylhexanoic acid and are mixed immediately before introduction into the mould. As it is desirable to have short cycle times for the casting in order to reduce labor costs, the viscosity of the urethane mixtures should preferably be below 150 poise. One so low. viscosity further allows rapid mixing of the various components. A viscosity of 50 poise or less is preferred. The mold is then filled and the mixture hardens. Mixtures according to the invention that use urethane polymers for tire stem blanks can usually be cured sufficiently within 5 min. after the mold is filled in such a way that the tire has sufficient strength to withstand immediate removal of the mold by means of mechanical devices without damaging the tire.

The following Table I indicates various mechanical properties for molded polyurethanes produced according to the present invention.

As can easily be seen from examples 1 and 2, polyurethane curing according to the present invention clearly provides significantly improved durability properties than the control samples as well as an unexpected increase in the curing speed or a reduction in the curing time.

EXAMPLE 1

Three size 145-13 tires were centrifugally cast from catalyzed elastomer compound which was fed in the correct proportions, mixed and distributed using a 3-component Admiral Elastomer Processing Maschine. Each of the three tires

was cured for one hour at 120°C and then tested for durability on an indoor wheel according to US.Department of Transportation specifications. Specimens with thickness

about. 2 mm was hardened integrated into each tire for determination of mechanical properties. Furthermore, ea. 15 x 5 x 0.2 cm sample pellets made from extra liquid elastomer which was

back after the tire mold had been filled, by curing in a pressure mold heated to 120°C. Double sets of these latter plates were removed from the mold after only 5 min. press time and then re-cured in an air circulation oven for the specified time and at the specified temperature for comparison of mechanical properties with sheets cured integrated in the tires.

Specified minimum mileage before failure, according to

D.O.T. criteria is about 2735 km (1700 miles) under exact conditions while tires manufactured according to the present invention failed after resp. about. 4,867 km (3,025 miles), about. 4827 .km (3000 miles) and about 5301 km (3295 miles). D.O.T. Durability test for 145-13 tires indicates initial operation at specific load and inflation (approx. 304 kg/tyre at approx. 68 kg/cm^ with gradually increased load as follows, the speed being kept at approx. 80, 5km",/.hour (50 miles per hour): 4 hours (about .322' km) under about 304 kg, then increase of

the load of approx. 338 kg and driving for 6 hours under approx. 338 kg load, then increase the load to approx. 362 kg and driving for 24 hours at 362 kg's load without failure.

■ After completion of the prescribed approx. After 2735 km, the test tires were found to have failed in the following way:

TIRE 1

After approx. 2735 km, the load had increased to approx. 394 kg and it was driven with this load for 8 hours (approx. 647 km) and the load was then increased to. about.' 442 kg in 8 hours (approx. 643 km)

and the load was then further increased to approx. 487kg for 8 hours (approx. 643 km), when the load was increased to approx. 533 kg. The tire was operated approx. 201 km (4867 km total) under approx. 533 kg before failure."

TIRE 2

This tire was subjected to identical loading conditions

and speed as tire No. 1 and failed, after approx. 161 km (approx. 4,827 km total) operation at a load of approx. 533 kg.

TIRE 3

Was subjected to the same stresses as tire #1 and tire #2

but was operated on for approx. 635 km (5301 km total) under 533 kg load before failure.

In comparison, numerous control tires failed after the average

8 hours at a load of approx. 442 kg (total approx. 4022 km). The composition of the control tires was the same as for tires 1, 2 'pg, 3 with the exception that they did not contain any "Flexol 4G0".

It is thus quite clear that large increases in duration were achieved.

"Adiprene L-367" is manufactured by DuPont and is polytetramethylene ether glycol ..with a molecular weight of approximately 1,000 end-capped with 2 molecules of "Hylene T.M.", i.e. approximately an 80/20 mixture of the 2,4/2,6-position isomers of toluene diisocyanate. "Caytur 21" is a complex of 4,4'-methylenedianiline and sodium chloride dispersion in 50% D.O.P.

EXAMPLE II

Two additional tires (145-13) were prepared as indicated in Example I for testing under D.O.T. high speed specification, which prescribes a minimum capability of 0.5 hours at approximately 157.5 km/h. It was reproduced approx. 2 mm plates for determining mechanical properties under different curing conditions. Particularly noteworthy are the superior mechanical properties obtained during testing at elevated temperature of the plates which were removed from the mold after 5 min. press hardening and then post-hardening in

60 min. at approximately 120°C in the fully relaxed state.

The applicable D.0.T. regulation for high-speed test for tires 145-13 prescribes a tire pressure of approx. 1.68 kg/cm 2a load of

about. 304 kg/pr. tires and the following driving times and speeds:

2.0 hour run-in at approximately 92.6 km/h, then increasing speed to approx. 138 km/h and driving for 0.5 hours at approx. 138 km/h, then increasing the speed to approx. 148 km/h and driving for 0.5 hours at 148 km/h and increasing the speed to approx. 157 km/h. The tire must then be driven for 0.5 hours at approx. 157 km/h without failure for passing the test.

In the case of test tires No. 4 and No. 5, the test was continued Beyond approx. 3.57 km/h to failure in the following way: 0.5 hours at approx. 167 km/h, 0.5 hours at approx. 167 km/h and after increasing the speed to approx. 185 km/h both tires failed after 12 min. at approx. 185 km/h.

In contrast, numerous control tires failed after an average of 0.2 hours at approx. 167 km/h. The control tires had the same composition as tires 5 and 6 with the exception that they did not contain any "Flexol 4G0".

Claims (41)

1. Cured polymer, characterized in that the on a weight basis contains 100 parts of an amine curable polymer or prepolymer selected from the group consisting of urethanes containing free isocyanate groups, epoxy resins, polymers containing acid halide and halogen-formate groups and polymers containing anhydride groups which react with diamines to give amide acid bonds, from 0.8 to 1.2 equivalents of a curing agent based on the free active groups of said amine curable polymer or prepolymer, the curing agent being selected from the group consisting of of a complex of 4,4'-methylene-dianiline and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, sodium nitrate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate, and sodium cyanide, and a complex of racemic 2.3-di (4-aminophenyl)butane and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium choride, rubidium bromide, rubidium iodide, cesium chloride, cesium bromide, eg cesium iodide, the ratio between the dianiline and the butane of the said salt in the said complex is about 3 mol per 1 mole and from about 1.0 to about 15.0 parts of an ester of formula where R' is a polyglycol containing in total from 2 .to._.5. carbon atoms and mixtures thereof, R is an aliphatic group containing from 4 to 9 carbon atoms, X is 1 or 2 and Y is an integer from 1 to 5. 2. Cured polymer as defined in claim 1, characterized by the fact that the area for equivalents of hardener are from 0.9 to 1.05. 3. Cured polymer as defined in claim 1, characterized by Xer2 and Yer4. 4: Cured polymer as stated in claim 3, characterized in that the ester is tetraethylene glycol di (2-ethylhexoate) and the curing agent complex is 4,4'-methylene-dianiline and a sodium chloride salt. 5. Cured polymer as stated in claim 1, characterized in that the amine curable polymer or prepolymer is a urethane containing free isocyanate groups. 6. Cured polymer as stated in claim 5, characterized in that the curing agent is 4,4'-methylene-dianiline complex containing a sodium chloride salt. 7. Cured polymer as stated in claim 6, characterized in that the range for equivalent curing agents is from 0.9 to 1.05. 8. Cured polymer as stated in claim 6, characterized in that the ester has an X value of 2 and a Y value of 4. 9. Cured polymer as stated in claim 8, characterized in that R' is selected from the group consisting of tetraethylene glycol, tetrapropylene glycol, tetrabutylene glycol, tetrapentylene glycol, diethylenedipropylene glycol, and propylene triethylene glycol and R is selected from the group consisting of butyl, pentyl, hexyl, heptyl, octyl , nonyl, and 2-ethylhexyl. 10. Cured polymer as set forth in claim 8, characterized in that the ester is selected from the group consisting of tetraethylene glycol di(2-ethylhexoate), . tetrapropylene glycol di(2-ethylhexoate), tetrabutylene glycol di(2-ethylhexoate), tetrapentylene glycol di(2-ethylhexoate), diethylenedipropylene glycol di(2-ethylhexoate), and propylene-triethyleneglycol di(2-ethylhexoate). v 11. Cured polymer as defined in claim 8, characterized in that the ester is tetraethylene glycol di(2-ethylhexoate). 12. Cured polymer as defined in claim 8, characterized in that the content of the ester is from 2 to 10 parts.a 13. Cured polymer as defined in claim 10, characterized in that the content of the ester is from 2.0 to 10.0 parts and that the number of equivalents of the curing agent is from 0.9 to 1.05. 14. Cured polymer as stated in claim 11, characterized in that the content of ester is from 3.0 to 9.0 parts and that equivalents of curing agent are from 0.9 to 1.05. 15. Cured polymer as stated in claim 10, characterized in that the urethane compounds are prepared from diols selected from the class consisting of polyethylene ether diol, polytrimethylene ester diol, polyhexamethylene ether diol, polypropylene terdiol and polytetramethylene ether diol. 16. Cured polymer as defined in claim 8, characterized in that it comprises softeners selected from the class consisting of dioctyl phthalate, diisooctyl phthalate, diisodecyl phthalate and dinonyl phthalate in an amount of from 4 to 20 parts. 17. Cured polymer as stated in claim 16, characterized in that X is 1 and Y is 1. 18. Cured polymer as defined in claim 8, characterized in that it comprises 0.3 to 3.0 parts of a light stabilizer. 19. Cured polymer as stated in claim 17, characterized in that the light stabilizer is selected from the group consisting of "carbon black", organic and inorganic dyes, the light stabilizers having an average particle size of 1 micron or less. 20. Cured polymer, characterized in that it contains, on a weight basis, 100 parts of an amine-curable polymer or prepolymer selected from the group consisting of halogen-containing hydrocarbon polymers, chlorosulfonated polymers and organopolysiloxanes, from about 0.0005 to 0.05 equivalents of a curing agent based on the active groups in said amine curable polymer or prepolymer, the curing agent being selected from a complex of 4,4'-methylenedianiline and salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, sodium nitrate, lithium chlorojfcd, lithium bromide, lithium iodide, lithium nitrate and sodium cyanide, and a complex of racemic 2,3-di(4-aminophenyl)butane and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium chloride, rubidium bromide, rubidium iodide, cesium chloride, cesium bromide, and cesium iodide, the ratio of aniline and butane to the salt complex being from 3 to 1 mole, and from 1.0 to 15.0 de laughs of an ester of formula in which R' is a polyglycol containing a total of from 2 to 5 carbon atoms and mixtures thereof, R is an aliphatic group containing from 4 to 9 carbon atoms, X is 1 or 2 and Y is an integer from 1 to 5. 21. Cured polymer as stated in claim 20, characterized in that equivalents of curing agent are from 0.005 to 0.05 parts. 22. Cured polymer as stated in claim 20, characterized in that the ester has an X-value of 2 and Y-value of 4. 23. Cured polymer as stated in claim 22, characterized in that the curing agent complex ■ is 4,4'-methylenedianiline and a sodium chloride salt. v 24. Cured polymer as stated in claim 23, characterized in that the ester is selected from the class consisting of tetraethylene glycol di(2-ethyl - hexoate), tetrapropylene glycol di ( 2 -ethylhexoate), tetrabutylengTycol"' di (2- ethyl hexoate) , te tr aperatyl englycol di C-2-ethylhexoate-) , di;ethyl en-,, -dipropyreneglycol' di(2-ethyl'hexbate) , and "propylene-triethyleneglycol di(2-ethyl-.hexoate) . 25. Cured polymer as stated in claim 24, characterized in that the catalyst is tetraethylene glycol di(2-ethylhexoate).' 26. Process for curing the amine-curable polymer or prepolymer specified in claims 1 and 20, in a reactor, characterized in that 100 parts by weight of the amine-curable polymer or prepolymer selected from the group consisting of urethanes containing free isocyanate groups are added . said amine-curable polymer or prepolymer, the curing agent being selected from the group consisting of a complex of 4,4'-methylene-dianiline and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, sodium nitrate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate and sodium cyanide, and a complex of racemic 2,3-di(4-aminophenyl)butane and a salt, the salt being selected from the group n consisting of sodium chloride, sodium bromide,. sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium chloride, rubidium iodide, rubidium bromide, cesium chloride, cesium bromide, and cesium iodide, the ratio of the dianiline or butane to the salt and complex being from 3 to 1 mole and from 1.0 to 15.0 parts of an ester with formula • wherein R' is a polyglycol containing totait from 2 to 5 carbon atoms and mixtures thereof, R is an aliphatic group containing from 4 to 9 carbon atoms, and X is an integer from 1 to 5. 27. Procedure as stated in claim 26, characterized in that 4,4'-methylene-dianiline and a sodium chloride salt are used as curing agent complex. 28. Method as stated in claim 26, characterized in that the ester has an X value of 2 and a Y value of 4. 29. Method as stated in claim 28, characterized in that 4,4'-methylene-dianiline and a sodium chloride salt are used as curing agent complex. 30.. Method as stated in claim 29, characterized in that a urethane containing free isocyanate groups is used as curable polymer. 31. Method as stated in claim 30, characterized in that urethanes are used produced from diols selected from the class consisting of polyethylene etherdiol, polytrimethylene etherdiol, polyhexamethylene etherdiol, polypropylene etherdiol and polytetramethylene etherdiol. 32. Method as set forth in claim 30, characterized in that the ester used is ester valg/f; from the group consisting of tetraethylene glycol di(2-ethylhexoate), tetrapropylene glycol di(2-ethylhexoate), tetrabutylene glycol di(2-ethylhexoate), tetrapentylene glycol di(2-ethylhexoate), diethylenedipropylene glycol di(2-ethylhexoate), and propylene-triethyleneglycol di(2-ethylhexoate). 2-ethylhexoate). 33. Process as stated in claim 32, characterized in that tetraethylene glycol di(2-ethylhexoate) is used as ester. 34. Method as stated in claim 28, characterized in that the curing is carried out at a temperature of from 90 to 170°C. 35. Procedure as stated in claim 34, characterized in that the ester is used in t v in amount of from 2.0 to 10.0 parts and that the curing agent is used in equivalent amounts of from 0.9 to 1.05 equivalents. 36. Process for curing the amine-curable polymer or prepolymer specified in claim 20 in a reaction vessel, characterized in that 100 parts of the amine-curable polymer or prepolymer are added on a weight basis, all from the group consisting of halogen-containing hydrocarbon polymers, chlorosulfonated polymers and organopolysiloxanes, from 0.0005 to 0.05 equivalents of a curing agent based on the active groups in the amine-curable polymer or prepolymer are added, the curing agent being selected from a complex of 4,4'-methylene/dianiline and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, sodium nitrate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate and sodium cyanide, and a complex of racemic 2,3'-di(4-aminophenyl)butane and a salt, the salt being selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, rubidium chloride, rubidium bromide, rubidium iodide, cesium chloride, cesiumb romide and cesium iodide, the ratio between the dianiline or butane and the salt in the complex being from 3 to 1 mole, and from about 1.0 to 15.0 parts of an ester of formula wherein R' is a polyglycol containing a total of from 2 to 5 carbon atoms and mixtures thereof, R is an aliphatic group containing from 4 to 9 carbon atoms, X is 1 or 2 and Y is an integer from 1 to 5. 37. Method as stated in claim 36, characterized in that the ester has an X value of 4 and a Y value of 2. 38...Procedure as stated in claim 37, characterized in that the curing agent complex is 4,4'-methylene-dianiline and a sodium chloride. >■ 39. Procedure as specified in claim 38. characterized in that the compositions are cured at a temperature from 90 to 170°C. 40. Method as stated in claim 39, characterized in that the ester is selected from the group consisting of tetraethylene glycol di(2-ethylhexoate), tetrapropylene glycol di(2-ethylhexoate), tetrabutylene glycol di(2-ethylhexoate), tetrapentylene glycol di(2-ethylhexoate) , diethylenedipropyleneglycol di(2-ethylhexoate), and propylene-triethyleneglycol di(2-ethylhexoate). 41. Method as stated in claim 40, characterized in that tetraethylene glycol di(2-ethylhexoate) is used as ester.