CA1193040A - Process for the production of polyurethane urea products - Google Patents
Process for the production of polyurethane urea productsInfo
- Publication number
- CA1193040A CA1193040A CA000418963A CA418963A CA1193040A CA 1193040 A CA1193040 A CA 1193040A CA 000418963 A CA000418963 A CA 000418963A CA 418963 A CA418963 A CA 418963A CA 1193040 A CA1193040 A CA 1193040A
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- Prior art keywords
- alkyl
- diamines
- nco
- molecular weight
- diphenylmethane
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a process for the production of polyurethane urea products from isocyanate product blends and preferably less reactive, aromatic diamines, or solutions of aromatic diamines in relatively high molecular weight polyhydroxyl compounds, the reaction components being reacted in a casting process with commercially-reasonable casting times and compara-tively short demolding times. For this purpose, rela-tively high-molecular weight polyhydroxyl compounds, optionally in the presence of low molecular weight diols are reacted with excess quantities of toluene, phenylene or hexamethylene diisocyanate to produce a substantially diisocyanate-free NCO-prepolymer. This NCO-prepolymer is mixed with from 0.1 to 25%, by weight, of less reactive, monomeric tetra-alkyl-diphenylmethane diisocyanates corresponding to the general formula:
wherein R1 to R4, which may be the same or different, represent C-1-C4 alkyl radicals.
These isocyanate blends may be easily processed into elastomer moldings having favorable properties in the casting process using moderately-reactive aromatic diamines from the series of di- to tetra-alkyl-diphenyl-methane diamines and/or dialkyl-toluene diamines and/or using substituted 3,5-diamino-4-alkyl-benzoic acid alkyl esters, optionally dissolved in the relatively high molecular weight polyhydroxyl compounds.
Mo-2439
This invention relates to a process for the production of polyurethane urea products from isocyanate product blends and preferably less reactive, aromatic diamines, or solutions of aromatic diamines in relatively high molecular weight polyhydroxyl compounds, the reaction components being reacted in a casting process with commercially-reasonable casting times and compara-tively short demolding times. For this purpose, rela-tively high-molecular weight polyhydroxyl compounds, optionally in the presence of low molecular weight diols are reacted with excess quantities of toluene, phenylene or hexamethylene diisocyanate to produce a substantially diisocyanate-free NCO-prepolymer. This NCO-prepolymer is mixed with from 0.1 to 25%, by weight, of less reactive, monomeric tetra-alkyl-diphenylmethane diisocyanates corresponding to the general formula:
wherein R1 to R4, which may be the same or different, represent C-1-C4 alkyl radicals.
These isocyanate blends may be easily processed into elastomer moldings having favorable properties in the casting process using moderately-reactive aromatic diamines from the series of di- to tetra-alkyl-diphenyl-methane diamines and/or dialkyl-toluene diamines and/or using substituted 3,5-diamino-4-alkyl-benzoic acid alkyl esters, optionally dissolved in the relatively high molecular weight polyhydroxyl compounds.
Mo-2439
Description
~.~9~Q ~O
Mo-2439 ~1~ Le~ 21,085 PROCESS FOR THE PRODUCTION OF POI.Y~RETHANE UREA PRODUCTS
. .
This invention relates to a process for the production of polyurethane urea products, which may be either cellular or elastomeric, from NCO-prepolymers which have increased NCO contents, and aromatic diamines, or solutions thereof in relatively high molecular weight polyhydroxyl compounds. ~ccording to this process, the reaction components are reacted in a casting process employing favorably long casting times and comparatively short demolding times.
For this purpose, relatively high molecular weight polyhydroxyl compounds, optionally in the presence of low molecular weight diols, are reacted with excess quantities of toluene, phenylene or hexamethylene diisocyanate to produce a substantially diisocyanate-free NCO-prepolymer. Then, from 0.1 to 25~, by weight, of less reactive, monomeric tetra-alkyl-diphenylmethane diisocyanates, corresponding to the general formula:
Rl R3 ~ C 2 wherein Rl to R4, which may be the same or different, represent Cl-C4 alkyl radicals, D:-~
are mixed with this NCO-prepolymer in order to increase the NCO content.
These isocyanate blends may then be easily processed, with moderately reactive diamines from the series of di- to tetra-alkyl-diphenylmethane diamines, Mo-2439 LeA 21 085-lJS
~ 363~
.
~ 2~
dialkyl-toluene diamines, and/or with 3,5-diamino-4-alkyl-benzoic acid alkyl esters or with solutions of these diamines in relatively high molecular weight polyhydroxyl compounds, into elastomer moldings having favora~le properties usins the ~nown casting process employing favorable processing conditions. Aromatic diamines, without alkyl substituents in the vicinity of each amino group and without deac-tivating substituents, such as, for example, diphenylmethane-4,4'-diamine, may also be used, but must be in the form of solutions thereof in relatively high molecular weight polyhydroxyl compounds.
BACKGROUND OF THE INVENTION
Polyurethane elastomers are preferably produced, according to the known casting process from, for example, NCO-prepolymers with glycols as chain-lengthening agents.
Particularly favorable properties are obtained using naphthylene diisocyanate or diphenylmethane diisocyanate with butane diol--1,4 (see Kunststoff-Handbuch, Vol. 7, Polyurethanes, Vieweg and Hochtlen, Carl-~anser~Verlag, Munich, 1966, pages 207 227). In order to achieve a high hardness in the elastomers, the diisocyanate is reacted with therelatively high molecular weight polyhydroxyl compounds in NCO:OH ratios of greater than
Mo-2439 ~1~ Le~ 21,085 PROCESS FOR THE PRODUCTION OF POI.Y~RETHANE UREA PRODUCTS
. .
This invention relates to a process for the production of polyurethane urea products, which may be either cellular or elastomeric, from NCO-prepolymers which have increased NCO contents, and aromatic diamines, or solutions thereof in relatively high molecular weight polyhydroxyl compounds. ~ccording to this process, the reaction components are reacted in a casting process employing favorably long casting times and comparatively short demolding times.
For this purpose, relatively high molecular weight polyhydroxyl compounds, optionally in the presence of low molecular weight diols, are reacted with excess quantities of toluene, phenylene or hexamethylene diisocyanate to produce a substantially diisocyanate-free NCO-prepolymer. Then, from 0.1 to 25~, by weight, of less reactive, monomeric tetra-alkyl-diphenylmethane diisocyanates, corresponding to the general formula:
Rl R3 ~ C 2 wherein Rl to R4, which may be the same or different, represent Cl-C4 alkyl radicals, D:-~
are mixed with this NCO-prepolymer in order to increase the NCO content.
These isocyanate blends may then be easily processed, with moderately reactive diamines from the series of di- to tetra-alkyl-diphenylmethane diamines, Mo-2439 LeA 21 085-lJS
~ 363~
.
~ 2~
dialkyl-toluene diamines, and/or with 3,5-diamino-4-alkyl-benzoic acid alkyl esters or with solutions of these diamines in relatively high molecular weight polyhydroxyl compounds, into elastomer moldings having favora~le properties usins the ~nown casting process employing favorable processing conditions. Aromatic diamines, without alkyl substituents in the vicinity of each amino group and without deac-tivating substituents, such as, for example, diphenylmethane-4,4'-diamine, may also be used, but must be in the form of solutions thereof in relatively high molecular weight polyhydroxyl compounds.
BACKGROUND OF THE INVENTION
Polyurethane elastomers are preferably produced, according to the known casting process from, for example, NCO-prepolymers with glycols as chain-lengthening agents.
Particularly favorable properties are obtained using naphthylene diisocyanate or diphenylmethane diisocyanate with butane diol--1,4 (see Kunststoff-Handbuch, Vol. 7, Polyurethanes, Vieweg and Hochtlen, Carl-~anser~Verlag, Munich, 1966, pages 207 227). In order to achieve a high hardness in the elastomers, the diisocyanate is reacted with therelatively high molecular weight polyhydroxyl compounds in NCO:OH ratios of greater than
2:1 to produce NCO-prepolymers which thus still contain portions of free diisocyanates, in addition to the NCO-prepolymers.
However, it has also been proposed to incre~se the NCO content of NCO-prepolymers, such as those based on toluene diisocyanate, by adding other, different diisocyanates and then to further react them with chain-length~ning agents (see Japanese Patent Application 53,133,298).
Mo-2439 As the NCO content increases, the ~ardness of the elastomer increases, but the casting time of the reaetion mixture is also redueed, and casting is praeticable only wit~ glycol-lengthening. With aromatic diamines as the chain-lengthenin~ agents, elastomers having improved elastic and thermal properties are, indeed, generally accessible, but they have a higher reactivity. Consequent-ly, the casting time is shortened in many cases to irnpracticably short times, unless diamines, such as 3,3'-dichloro-4,4'-diamino-diphenylmethane, whieh have considerably reduced reactivities (but, unfortunately, also high melting pointsl, are used. Even with these diamines, however, the casting time is extremely short (partieularly with NCO-enriehed prepolymer mixtures) and partly as a result of this, the easting process eannot be carried out on a praetical basis.
The reaction of eonventional NCO-prepolymers with ehain-lengthening agents, such as, for example, di-ethyl-tolamines, tetra-alkyl-4,4'-diamino-diphenvlmethanes or 4 alkyl-3,5-diamino-benzoic acid alkyl esters, is also diffieult beeause of similar short reaetivities.
Thus, proeessing with eommereially available isoeyanates, sueh as diphenylmethane diisoeyanate or naphthylene diisoeyanate, in the form of NCO-prepolymers, is only possible with very short, impraetieable easting times (i.e., < 5 seeonds). Large east parts or eomparatively long flow paths are, thus, hardly feasible ~see, Example 4, Table l, herein).
~f reduetion of the reaetivity of these diamines is attempted by diluting them with relatively high moleeular weight polyhydroxyl eompounds (such as, for example, adipic aeid/C2-C6-diol polyesters), the results are unsatisfaetory. A slight inerease in the Mo-2439 ~3~
, -4~
casting time is indeed achieved, ~ut this has to be ~alanced against a concurrent and disproportionate increase in the demolding time (see, Example 10, Table 2, herein).
It has now heen found that NCO-prepolymers, based on toluene diisocyanate, phenylene diisocyanate or hexamethylene diisocyanate with polyester and/or poly-ether diols and blended with tetra-alkyl-diphenylmethane diisocyanate, then combined with liquid or low-melting aromatic diamines, may easily be processed into cast parts, even in high pressure installations. These diamines may be less reactive diamines used alone, or in the form of solutions of less reactive diamines in relatively high molecular weight polyhydroxyl compounds and/or, surprisingly, even in the form of solutions of reactive, aromatic diamines, such as diphenylmethane-4,4'-diamine, in relatively high molecular weight poly-hydroxyl compounds. During processing, a gradual change in hardness may be obtained by varying the quantity of the added diisocyanates. Moreover, the casting times are long enough for large-volume parts to be produced (see Examples 5 to 9, Table 1 and Examples 11 to 13, Table 2, herein) and the parts may be released from the mold after relatively short molding times.
It is surprising that, in spite of the simultaneous use of different diisocyanates in the casting mixture, - the mechanical properties of the end products, whic~h are obtained according to the present invention, are outstanding. Normally, the mixing of several different isocyanate components in the polyurea system causes the production of different urea segments which interfere with each other and thus exert a negative influence on the mechanical property spectrum (particularly on the Mo-2439
However, it has also been proposed to incre~se the NCO content of NCO-prepolymers, such as those based on toluene diisocyanate, by adding other, different diisocyanates and then to further react them with chain-length~ning agents (see Japanese Patent Application 53,133,298).
Mo-2439 As the NCO content increases, the ~ardness of the elastomer increases, but the casting time of the reaetion mixture is also redueed, and casting is praeticable only wit~ glycol-lengthening. With aromatic diamines as the chain-lengthenin~ agents, elastomers having improved elastic and thermal properties are, indeed, generally accessible, but they have a higher reactivity. Consequent-ly, the casting time is shortened in many cases to irnpracticably short times, unless diamines, such as 3,3'-dichloro-4,4'-diamino-diphenylmethane, whieh have considerably reduced reactivities (but, unfortunately, also high melting pointsl, are used. Even with these diamines, however, the casting time is extremely short (partieularly with NCO-enriehed prepolymer mixtures) and partly as a result of this, the easting process eannot be carried out on a praetical basis.
The reaction of eonventional NCO-prepolymers with ehain-lengthening agents, such as, for example, di-ethyl-tolamines, tetra-alkyl-4,4'-diamino-diphenvlmethanes or 4 alkyl-3,5-diamino-benzoic acid alkyl esters, is also diffieult beeause of similar short reaetivities.
Thus, proeessing with eommereially available isoeyanates, sueh as diphenylmethane diisoeyanate or naphthylene diisoeyanate, in the form of NCO-prepolymers, is only possible with very short, impraetieable easting times (i.e., < 5 seeonds). Large east parts or eomparatively long flow paths are, thus, hardly feasible ~see, Example 4, Table l, herein).
~f reduetion of the reaetivity of these diamines is attempted by diluting them with relatively high moleeular weight polyhydroxyl eompounds (such as, for example, adipic aeid/C2-C6-diol polyesters), the results are unsatisfaetory. A slight inerease in the Mo-2439 ~3~
, -4~
casting time is indeed achieved, ~ut this has to be ~alanced against a concurrent and disproportionate increase in the demolding time (see, Example 10, Table 2, herein).
It has now heen found that NCO-prepolymers, based on toluene diisocyanate, phenylene diisocyanate or hexamethylene diisocyanate with polyester and/or poly-ether diols and blended with tetra-alkyl-diphenylmethane diisocyanate, then combined with liquid or low-melting aromatic diamines, may easily be processed into cast parts, even in high pressure installations. These diamines may be less reactive diamines used alone, or in the form of solutions of less reactive diamines in relatively high molecular weight polyhydroxyl compounds and/or, surprisingly, even in the form of solutions of reactive, aromatic diamines, such as diphenylmethane-4,4'-diamine, in relatively high molecular weight poly-hydroxyl compounds. During processing, a gradual change in hardness may be obtained by varying the quantity of the added diisocyanates. Moreover, the casting times are long enough for large-volume parts to be produced (see Examples 5 to 9, Table 1 and Examples 11 to 13, Table 2, herein) and the parts may be released from the mold after relatively short molding times.
It is surprising that, in spite of the simultaneous use of different diisocyanates in the casting mixture, - the mechanical properties of the end products, whic~h are obtained according to the present invention, are outstanding. Normally, the mixing of several different isocyanate components in the polyurea system causes the production of different urea segments which interfere with each other and thus exert a negative influence on the mechanical property spectrum (particularly on the Mo-2439
3~
heat stability and the pressure de~ormation residue) of the end product. However, good ~alues are actually found precisel~ in the critical characteristi.cs of heat sta~ility and pressure deformation residue in the products o~tained according to the instant invention.
The reactivity gradation,and thus the processi~ility, is also very favorably effected.
In contrast to high-meltin~ diamines, such as 3,3' dichloro-4,4'-diamino-diphenylmethane, which are slow to react, liquid or low-melting chain-lengthening diamines have a moderate reactivity. Examples o~ these low-melting diamines include diethyl-tolamines or the (liquid) mixtures thereof, or the mixed condensates from, for example, diethyl aniline, diisopropyl aniline and lS formaldehyde (such as tetra-alkyl-4,4'-diamino-diphenyl-methane), which may be easi'y processed as diamine melts in high pressure installations.
Alkylated diphenylmethane diisocyanate compounds, and the use thereof in polyurethanes, have been known for a long time. Thus, ~ritish Patent 852,651 describes the production of tetra-alkylated diphenylmethane diisocyanates and indicates the suitability thereof for the production of polyurethanes. However, experiments have now shown that formulations which are composed exclusively of tetra-alkyl-diphenylmethane diisocyanates produce waxy-brittle bodies during the reaction with aromatic diamines as chain-lengthening agent, which bodies may only be strengthened by an abnorma].ly-~ong subsequent heating operation (see Table 1, Examples 1 and 2, herein~. Due to this peculiarity, a commercial use of the resulting products is impossible, in spite of some useful mechanical properties.
Mo-2439 ~3~
-6~
In the method according to the present invention, the production of a brittle, waxy structure is not observed, in spite of the use of tetra-alkyl-diphenyl-methane diisocyanate. On the contrary, moldings which have favorable properties are obtained with practicable casting times and short molding times.
DESCRIPTION OF THE INVENTION
Thus, the present invention provides a process for the production of polyurethane urea products, which may be either cellular or elas-tomeric, by the reaction of NCO-prepolymers and blended with quantities of certain monomeric polyisocyanates, with aromatic diamines, or with solutions of these diamines in relatively high molecular weight polyhydroxyl compounds, and optionally catalysts and conventional additives.
These substantially-linear NCO-prepolymers, which contain less than 0.2~, preferably less than 0.05~, unreacted monomeric diisocyanate (optionally by distilling off unreacted diisocyanates), are produced from substantially-linear relatively high molecular weigh~
polyhydroxyl compounds which have a molecular weight of from 400 to 12,000, preferably of from 400 to 5000, to which, optionally, have been added low molecular weight diols which have a molecular weight of from 62 to 399, preferabl~ of from 62 to 350, reacted with toluene diisocyanate, phenylene diisocyanate or hexamethylene diisocyanate, preferably toluene diisocyanate, in an NCO:OH ratio of greater than 1.1:1, preferably of from 1.1:1 to 2.5:1 arld more preferably, of from 1.5:1 to 2.1:1. This NCO-prepolymer is th n blended with from 0.1 to 25~, by weight, preferably from 0.5 to 20%, by weight, and more preferably, from 0.5 to 15~, by weight, of diphenylmethane diisocyanates which are ~50-2439 ~3~
~7-tetra-alkyl-substituted in the _-positions to the NCO
groups, which correspond to the general formula:
Rl R3 ~ \ ,/ ~ NC~
wherein Rl, R2, R3 and R4, which may be the same or different represent straight- or branched-chain Cl-C4 alkyl groups.
This blended product is then reacted with aromatic diamines, optionally dissolved in relatively high molecular weight polyhydroxyl compounds, said diamine selected:
(a) from the series of di- to tetra-alkyl-diphenyl diamines corresponding to the general formula:
Rl R3 wherein Rl to R4, which may be the same or different, represent straight- or ~ranch.ed-chain Cl-C~ alkyl groups, and/or wherein R2 and/or R4 may represent hydrogen; and/or (b) from the seri.es of dialkyl-toluene diamines corresponding to the general formulae:
Mo-2439 ~3~
~8-and ;~
wherein R5, which may be the same or different, represents straight- or branched-chain Cl-C5 alkyl groups, preferably ethyl; and/or (c) from the 3,5-diamino-4-alkyl-benzoic acid alkylester series, corresponding to the general formula:
o c -OR6 wherein 0 X represents a Cl-C12 alkyl, preferably methyl, ethyl, isopropyl or isobutyl; and R6 represents straight- or branched-chain Cl-C10 alkyl radicals; and/or (d) solutions of reactive aromatic diamines without alkyl groups in the vicinity of each amino group and without deactivating substituents, SUch as, preferably, diphenyl-methane-4,4'-diamine, in relatively high-molecular weight polyhydroxyl compounds.
These diamines or diamine mixtures are used in substantially equivalent ~uantities (NH2: NCQ or OH + NH2: NCO of from 0.8:1 to 1.2:1, preferably of from 0.9:1 to 1.05:1).
Mo-24 39 ~3~
Included among suitable subs~antially-linear polyols with molecula~ weig~ts of from 400 to 12000, which preferably contain 2, optionally up to 3, Zerewitinoff-active H-gro~ps, which are ~eactive against NC0-g~oups r~ubstantia11y hydroxyl groups), are the known polyesters, polylactones, polyethers, polythioethers, polyesteramides, polycarbonates and polyacetals. Also, hydroxyl-terminated vinyl polymers, such as, for example, polybutadiene diols; polyhydroxyl compounds which contain urethane or urea groups;
optionally modified natural polyols, and compounds containing other Zerewitinoff-active groups, such as amino, carboxyl or thiol groups may be used. These compounds correspond to the prior art and are described in detail, for example, in German Auslegeschriften 15 2,302,564; 2,423,764; 2,549,372 (~.S. Patent 3,963,679~;
2,402,840 (U.S. Patent 3,984,607); 2,497,387 (U.S.
Patent 4,035,213) and, in particular, 2,854,384.
The preferred polyols according to the instant invention include polyes-ters containing hydroxyl 20 groups, obtained from dihydricalcohols and adipic acid; polycarbonates; polycaprolactones; polyethylene oxide polyethers; polypropylene oxide polyethers;
polytetrahydrofuran po]yethers and mixed polyethers of ethylene oxide and propylene oxide and/or optionally ~5 tetrahydrofuran. Adipic acid diol ester, in particular, adipic acid/C2-C6 diol polyester, caprolactone polyester or polycarbonate diols, in particular, hexane diol polycarbonates, which are optionally modified by co-components, are particularly preferred. ~lowever, mixtures 30 of the~relatively high molecular weight compounds containing hydroxyl groups may also be used.
Preferred low molecular weight diols, optionally to be used simultaneously, include ethylene glycol, di-and triethylene glycol, and, in particular, l,6-hexane Mo-2~39 ~3~
diol, neopentyl gl~col, 2-methyl-propane diol and hydroquinone-di-~-hydroxyethyl ether. In most cases, 1,4-butane diol is most preferable.
As described, toluene diisocyanates, phenylene diisocyanate and hexamethylene diisocyanate are particular-ly preferred as dilsocyanates, due to the ease of distillation thereof. Toluene diisocyanates, in conven-tional isomer mixtures, are particularly preferred, and toluene-2,4-diisocyanate is most particularly preferred.
The NCO-prepolymers are formed by reacting the relatively high molecular weight polyhydroxyl compounds with excess quantities (>1.1:1 NCO:OH) of diisocyanates.
The low molecular weight diols may optionally be used as chain-lengthening agents in admixture with the relatively high molecular weight polyhydroxyl compounds, or they may be added subsequently to the formation of the NCO-prepolymer.
The quantity of diisocyanates which is used is preferably from 1.5 to 2.5, and mos-t prefexably from 1.5 to 2.1, NCO equivalents per OH e~uivalent.
During the production of the NCO-prepolymers, it is possible to use a very much higher NCO:OH ratio (for example, up to 10.0:1), but the content of free diisocyanates of the type mentioned must then be removed again by distillation in order that the effective NCO:OH ratios specified are observed. It is even preferred initially to carry out the NCO-prepolymer formation using a very great NCO excess, approaching the ideal NCO:OH ratio of 2:1, in order to limit the lin~ing of two relatively high molecular weight poly-hydroxyl compounds. ~fter unreacted diisocyanates have been distilled off~ for example, in a thin-film evaporator, a substantially monomer-free NCO-prepolymer Mo-2439 o wh~ch contains less than 0.2%, b~ weight, more pre~erably less than 0.05~, by weight, of monomeric diisocyanate, should remain.
The NCO content of this su~stantially monomeric-free ~CO-prepolymer is blended ~it~ 0.1 to 25~, by weight, prefera~ly from 0.5 to 20~, by weight, and more preferably from 0.5 to 15%, by weight, diphenyl-methane diisocyanates which are tetra-alkyl-substituted in _-positions to the NCO groups and which correspond to the general formula:
Rl R3 OCN ~ NCO
In this general formula for these tetra-alkyl-diphenyl-methane diisocyanates, Rl, R2, R3 and R4 represent the same or different alkyl radicals having from 1 to 4 carbon atoms, such as, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or t-butyl groups. Mixtures of such individual compounds with any radicals Rl to R4 may also be used.
Suitable d:iisocyanates for blending with the NCO-prepolymers include the tetramethyl, tetraethyl, tetrapropyl, tetraisopropyl, tetra-n-butyl, tetraiso-butyl and/or tetra-t-butyl derivatives of diphenylmethane diisocyanates, in particular, 4,4'-diisocyanates.
However, the derivatives having asymmetric alkyl sub-stitution on the two phenyl nuclei are also suitable.Such derivatives include, for example, 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diisocyanate, Mo-2439 ~3~
3,5-diethyl-3',5'-diisobutyl-diphenylmethane-4,4'-diisocyanate or other asymmetrically-substituted tetra-alkyl-diphenylmethane diisocyanates, which are produced by the condensation of differently alkyl-substituted dialkyl anilines with formaldehyde and subsequent phosgenation. Product mixtures comprising asymmetrically-substituted tetra-alkyl-diphenylmethane diisocyanates mixed with its symmetrical components are particularly preferred. Examples of these preferred mixtures include ln mixtures of, for example, from 45 to 65%, by weight, of 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diisocyanate and from 27.5 to 17.5%, by weight, of 3,5,3',5'-tetraethyl-diphenylmethane-4,4'-diisocyanate and from 27.5 to 17.5%, by weight, of 3,5,3',5'-tetra-isopropyl-diphenylmethane-4,4'-diisocyanate. The production of asymmetrically-substituted alkyl-diphenylmethane diamines which may be phosgenated into the corresponding isocyanates is described, for example, in German Auslegeschrift 2,920,501.
The resulting isocyanate blends of NCO-prepolymer with tetra-alkyl-diphenylmethane diisocyanates, should preferably contain at least 4%, by weight, of NCO, preferably from 4 to 9%, by weight, and more preferably from 4 to 7%, by weight, of NCO.
In the production of these isocyanate blends, minor quantities, generally less than 5 mol percent of higher functional compounds, for example, trifunctional compounds, may optionally be used in each of the starting materials, but the quantity must be restricted such that the properties are not substantially modified and merely the molecular weight is affected. In the alternativer monofunctional compounds (monofunctional hydroxy compounds, monounction-al isocyanates or monofunctional amines) may optionally be simultaneously used as chain-terminators to control the molecular weight.
Mo-2439 3~
Of course, the conventional hydrolysis and oxidation stabilizers may also be added to the starting compounds.
It is advisable to add anti-oxidants for sta~ilizing the polyurethane, such anti-oxidants being sterically-hindered phenols, organic phosphites and/or phosphoni-tes, and/or conventional W absorbers and light protecting agents based on benzotriazole, 2,2,6,6-tetramethyl~
piperidine, 1,2,2,6,6~pentamethylpiperidine or benzo-phenone, and/or other types of W absorbers. Other additives, pigments, dyes or reinforcing fibers may also be admixed according to the prior ar~.
~ he isocyanate blends are lengthened according to the present invention using aromatic diamines, optionally dissolved in relatively high molecular weight poly-hydroxyl compounds and/or using solutions of reactivearomatic diamines in relatively high molecular weight polyhydroxyl compcunds.
The preferred aromatic diamines from the series of di- to tetra-alkyl-diphenylmethane diamines correspond to the general formula:
Rl / 3 H2N ~ NH2 ,~ CH2 wherein Rl to R4, which may be the same or different, represent straight- or branched-chain aliphatic alkyl radicals having from 1 to 4 carbon atoms, and/or wherein R2 and/or R4 may represent hydrogel-.
Mo-2439 ~14-~ Examples of such diamines include tetramethyl~, tetraethyl-,tetrapropyl-, tetraisopropyl-, tetrabutyl-, tetraiso~utyl- and/or, optionally, tetra-t-~utyl-diphenylme~hane-4,4'-diamines, with asymmetrically-alkyl-substituted tetra-alkyl-diphenylmethane diamines prepared from differently-substituted dialkyl anilines and formaldehyde preferred. Examples of such preferred diamines includc 3,5-diethyl-3',5'-diisopropyl-diphenyl-methane-4,4~-diamine, 3,5-dimethyl--3',5'-diisobutyl-diphenylme~hane-4,4'-diamine, 3,5-dimethyl-3',5'-diisopropyl-diphenylmethane diamine, and mixtures of the asymmetrically-substituted and symmetrically-substituted tetra-alkyl-diphenylmethanes. The production of such asymmetrically-substituted tetra-alkyl-diphenyl-methane diamines and of the mixtures thereof withsymmetrically-substituted tetra-alkyl-diphenylmethane diamines is described, for example, in German Auslege-schrift 2,920,501.
Trialkyl-substituted diphenylmethane diamines, such as, for example, 3,5,3'-triisopropyl-diphenyl-methane-4,4'-diamine and 3,5-diisopropyl-3'-ethyl-diphenylmethane-4,4'-diamine may also be used. Dialkyl-diphenylmethane diamines, such as 3,3'-diisopropyl-diphenylmethane-4,4'-diamine, may also be used, but are less preferred. However, mixtures of from about 45 to 65%, by weight, of 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diamine, from 27.5 to 17.5~, by weight, of 3,5,3',5'-tetraethyl-diphenylmetharle-
heat stability and the pressure de~ormation residue) of the end product. However, good ~alues are actually found precisel~ in the critical characteristi.cs of heat sta~ility and pressure deformation residue in the products o~tained according to the instant invention.
The reactivity gradation,and thus the processi~ility, is also very favorably effected.
In contrast to high-meltin~ diamines, such as 3,3' dichloro-4,4'-diamino-diphenylmethane, which are slow to react, liquid or low-melting chain-lengthening diamines have a moderate reactivity. Examples o~ these low-melting diamines include diethyl-tolamines or the (liquid) mixtures thereof, or the mixed condensates from, for example, diethyl aniline, diisopropyl aniline and lS formaldehyde (such as tetra-alkyl-4,4'-diamino-diphenyl-methane), which may be easi'y processed as diamine melts in high pressure installations.
Alkylated diphenylmethane diisocyanate compounds, and the use thereof in polyurethanes, have been known for a long time. Thus, ~ritish Patent 852,651 describes the production of tetra-alkylated diphenylmethane diisocyanates and indicates the suitability thereof for the production of polyurethanes. However, experiments have now shown that formulations which are composed exclusively of tetra-alkyl-diphenylmethane diisocyanates produce waxy-brittle bodies during the reaction with aromatic diamines as chain-lengthening agent, which bodies may only be strengthened by an abnorma].ly-~ong subsequent heating operation (see Table 1, Examples 1 and 2, herein~. Due to this peculiarity, a commercial use of the resulting products is impossible, in spite of some useful mechanical properties.
Mo-2439 ~3~
-6~
In the method according to the present invention, the production of a brittle, waxy structure is not observed, in spite of the use of tetra-alkyl-diphenyl-methane diisocyanate. On the contrary, moldings which have favorable properties are obtained with practicable casting times and short molding times.
DESCRIPTION OF THE INVENTION
Thus, the present invention provides a process for the production of polyurethane urea products, which may be either cellular or elas-tomeric, by the reaction of NCO-prepolymers and blended with quantities of certain monomeric polyisocyanates, with aromatic diamines, or with solutions of these diamines in relatively high molecular weight polyhydroxyl compounds, and optionally catalysts and conventional additives.
These substantially-linear NCO-prepolymers, which contain less than 0.2~, preferably less than 0.05~, unreacted monomeric diisocyanate (optionally by distilling off unreacted diisocyanates), are produced from substantially-linear relatively high molecular weigh~
polyhydroxyl compounds which have a molecular weight of from 400 to 12,000, preferably of from 400 to 5000, to which, optionally, have been added low molecular weight diols which have a molecular weight of from 62 to 399, preferabl~ of from 62 to 350, reacted with toluene diisocyanate, phenylene diisocyanate or hexamethylene diisocyanate, preferably toluene diisocyanate, in an NCO:OH ratio of greater than 1.1:1, preferably of from 1.1:1 to 2.5:1 arld more preferably, of from 1.5:1 to 2.1:1. This NCO-prepolymer is th n blended with from 0.1 to 25~, by weight, preferably from 0.5 to 20%, by weight, and more preferably, from 0.5 to 15~, by weight, of diphenylmethane diisocyanates which are ~50-2439 ~3~
~7-tetra-alkyl-substituted in the _-positions to the NCO
groups, which correspond to the general formula:
Rl R3 ~ \ ,/ ~ NC~
wherein Rl, R2, R3 and R4, which may be the same or different represent straight- or branched-chain Cl-C4 alkyl groups.
This blended product is then reacted with aromatic diamines, optionally dissolved in relatively high molecular weight polyhydroxyl compounds, said diamine selected:
(a) from the series of di- to tetra-alkyl-diphenyl diamines corresponding to the general formula:
Rl R3 wherein Rl to R4, which may be the same or different, represent straight- or ~ranch.ed-chain Cl-C~ alkyl groups, and/or wherein R2 and/or R4 may represent hydrogen; and/or (b) from the seri.es of dialkyl-toluene diamines corresponding to the general formulae:
Mo-2439 ~3~
~8-and ;~
wherein R5, which may be the same or different, represents straight- or branched-chain Cl-C5 alkyl groups, preferably ethyl; and/or (c) from the 3,5-diamino-4-alkyl-benzoic acid alkylester series, corresponding to the general formula:
o c -OR6 wherein 0 X represents a Cl-C12 alkyl, preferably methyl, ethyl, isopropyl or isobutyl; and R6 represents straight- or branched-chain Cl-C10 alkyl radicals; and/or (d) solutions of reactive aromatic diamines without alkyl groups in the vicinity of each amino group and without deactivating substituents, SUch as, preferably, diphenyl-methane-4,4'-diamine, in relatively high-molecular weight polyhydroxyl compounds.
These diamines or diamine mixtures are used in substantially equivalent ~uantities (NH2: NCQ or OH + NH2: NCO of from 0.8:1 to 1.2:1, preferably of from 0.9:1 to 1.05:1).
Mo-24 39 ~3~
Included among suitable subs~antially-linear polyols with molecula~ weig~ts of from 400 to 12000, which preferably contain 2, optionally up to 3, Zerewitinoff-active H-gro~ps, which are ~eactive against NC0-g~oups r~ubstantia11y hydroxyl groups), are the known polyesters, polylactones, polyethers, polythioethers, polyesteramides, polycarbonates and polyacetals. Also, hydroxyl-terminated vinyl polymers, such as, for example, polybutadiene diols; polyhydroxyl compounds which contain urethane or urea groups;
optionally modified natural polyols, and compounds containing other Zerewitinoff-active groups, such as amino, carboxyl or thiol groups may be used. These compounds correspond to the prior art and are described in detail, for example, in German Auslegeschriften 15 2,302,564; 2,423,764; 2,549,372 (~.S. Patent 3,963,679~;
2,402,840 (U.S. Patent 3,984,607); 2,497,387 (U.S.
Patent 4,035,213) and, in particular, 2,854,384.
The preferred polyols according to the instant invention include polyes-ters containing hydroxyl 20 groups, obtained from dihydricalcohols and adipic acid; polycarbonates; polycaprolactones; polyethylene oxide polyethers; polypropylene oxide polyethers;
polytetrahydrofuran po]yethers and mixed polyethers of ethylene oxide and propylene oxide and/or optionally ~5 tetrahydrofuran. Adipic acid diol ester, in particular, adipic acid/C2-C6 diol polyester, caprolactone polyester or polycarbonate diols, in particular, hexane diol polycarbonates, which are optionally modified by co-components, are particularly preferred. ~lowever, mixtures 30 of the~relatively high molecular weight compounds containing hydroxyl groups may also be used.
Preferred low molecular weight diols, optionally to be used simultaneously, include ethylene glycol, di-and triethylene glycol, and, in particular, l,6-hexane Mo-2~39 ~3~
diol, neopentyl gl~col, 2-methyl-propane diol and hydroquinone-di-~-hydroxyethyl ether. In most cases, 1,4-butane diol is most preferable.
As described, toluene diisocyanates, phenylene diisocyanate and hexamethylene diisocyanate are particular-ly preferred as dilsocyanates, due to the ease of distillation thereof. Toluene diisocyanates, in conven-tional isomer mixtures, are particularly preferred, and toluene-2,4-diisocyanate is most particularly preferred.
The NCO-prepolymers are formed by reacting the relatively high molecular weight polyhydroxyl compounds with excess quantities (>1.1:1 NCO:OH) of diisocyanates.
The low molecular weight diols may optionally be used as chain-lengthening agents in admixture with the relatively high molecular weight polyhydroxyl compounds, or they may be added subsequently to the formation of the NCO-prepolymer.
The quantity of diisocyanates which is used is preferably from 1.5 to 2.5, and mos-t prefexably from 1.5 to 2.1, NCO equivalents per OH e~uivalent.
During the production of the NCO-prepolymers, it is possible to use a very much higher NCO:OH ratio (for example, up to 10.0:1), but the content of free diisocyanates of the type mentioned must then be removed again by distillation in order that the effective NCO:OH ratios specified are observed. It is even preferred initially to carry out the NCO-prepolymer formation using a very great NCO excess, approaching the ideal NCO:OH ratio of 2:1, in order to limit the lin~ing of two relatively high molecular weight poly-hydroxyl compounds. ~fter unreacted diisocyanates have been distilled off~ for example, in a thin-film evaporator, a substantially monomer-free NCO-prepolymer Mo-2439 o wh~ch contains less than 0.2%, b~ weight, more pre~erably less than 0.05~, by weight, of monomeric diisocyanate, should remain.
The NCO content of this su~stantially monomeric-free ~CO-prepolymer is blended ~it~ 0.1 to 25~, by weight, prefera~ly from 0.5 to 20~, by weight, and more preferably from 0.5 to 15%, by weight, diphenyl-methane diisocyanates which are tetra-alkyl-substituted in _-positions to the NCO groups and which correspond to the general formula:
Rl R3 OCN ~ NCO
In this general formula for these tetra-alkyl-diphenyl-methane diisocyanates, Rl, R2, R3 and R4 represent the same or different alkyl radicals having from 1 to 4 carbon atoms, such as, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or t-butyl groups. Mixtures of such individual compounds with any radicals Rl to R4 may also be used.
Suitable d:iisocyanates for blending with the NCO-prepolymers include the tetramethyl, tetraethyl, tetrapropyl, tetraisopropyl, tetra-n-butyl, tetraiso-butyl and/or tetra-t-butyl derivatives of diphenylmethane diisocyanates, in particular, 4,4'-diisocyanates.
However, the derivatives having asymmetric alkyl sub-stitution on the two phenyl nuclei are also suitable.Such derivatives include, for example, 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diisocyanate, Mo-2439 ~3~
3,5-diethyl-3',5'-diisobutyl-diphenylmethane-4,4'-diisocyanate or other asymmetrically-substituted tetra-alkyl-diphenylmethane diisocyanates, which are produced by the condensation of differently alkyl-substituted dialkyl anilines with formaldehyde and subsequent phosgenation. Product mixtures comprising asymmetrically-substituted tetra-alkyl-diphenylmethane diisocyanates mixed with its symmetrical components are particularly preferred. Examples of these preferred mixtures include ln mixtures of, for example, from 45 to 65%, by weight, of 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diisocyanate and from 27.5 to 17.5%, by weight, of 3,5,3',5'-tetraethyl-diphenylmethane-4,4'-diisocyanate and from 27.5 to 17.5%, by weight, of 3,5,3',5'-tetra-isopropyl-diphenylmethane-4,4'-diisocyanate. The production of asymmetrically-substituted alkyl-diphenylmethane diamines which may be phosgenated into the corresponding isocyanates is described, for example, in German Auslegeschrift 2,920,501.
The resulting isocyanate blends of NCO-prepolymer with tetra-alkyl-diphenylmethane diisocyanates, should preferably contain at least 4%, by weight, of NCO, preferably from 4 to 9%, by weight, and more preferably from 4 to 7%, by weight, of NCO.
In the production of these isocyanate blends, minor quantities, generally less than 5 mol percent of higher functional compounds, for example, trifunctional compounds, may optionally be used in each of the starting materials, but the quantity must be restricted such that the properties are not substantially modified and merely the molecular weight is affected. In the alternativer monofunctional compounds (monofunctional hydroxy compounds, monounction-al isocyanates or monofunctional amines) may optionally be simultaneously used as chain-terminators to control the molecular weight.
Mo-2439 3~
Of course, the conventional hydrolysis and oxidation stabilizers may also be added to the starting compounds.
It is advisable to add anti-oxidants for sta~ilizing the polyurethane, such anti-oxidants being sterically-hindered phenols, organic phosphites and/or phosphoni-tes, and/or conventional W absorbers and light protecting agents based on benzotriazole, 2,2,6,6-tetramethyl~
piperidine, 1,2,2,6,6~pentamethylpiperidine or benzo-phenone, and/or other types of W absorbers. Other additives, pigments, dyes or reinforcing fibers may also be admixed according to the prior ar~.
~ he isocyanate blends are lengthened according to the present invention using aromatic diamines, optionally dissolved in relatively high molecular weight poly-hydroxyl compounds and/or using solutions of reactivearomatic diamines in relatively high molecular weight polyhydroxyl compcunds.
The preferred aromatic diamines from the series of di- to tetra-alkyl-diphenylmethane diamines correspond to the general formula:
Rl / 3 H2N ~ NH2 ,~ CH2 wherein Rl to R4, which may be the same or different, represent straight- or branched-chain aliphatic alkyl radicals having from 1 to 4 carbon atoms, and/or wherein R2 and/or R4 may represent hydrogel-.
Mo-2439 ~14-~ Examples of such diamines include tetramethyl~, tetraethyl-,tetrapropyl-, tetraisopropyl-, tetrabutyl-, tetraiso~utyl- and/or, optionally, tetra-t-~utyl-diphenylme~hane-4,4'-diamines, with asymmetrically-alkyl-substituted tetra-alkyl-diphenylmethane diamines prepared from differently-substituted dialkyl anilines and formaldehyde preferred. Examples of such preferred diamines includc 3,5-diethyl-3',5'-diisopropyl-diphenyl-methane-4,4~-diamine, 3,5-dimethyl--3',5'-diisobutyl-diphenylme~hane-4,4'-diamine, 3,5-dimethyl-3',5'-diisopropyl-diphenylmethane diamine, and mixtures of the asymmetrically-substituted and symmetrically-substituted tetra-alkyl-diphenylmethanes. The production of such asymmetrically-substituted tetra-alkyl-diphenyl-methane diamines and of the mixtures thereof withsymmetrically-substituted tetra-alkyl-diphenylmethane diamines is described, for example, in German Auslege-schrift 2,920,501.
Trialkyl-substituted diphenylmethane diamines, such as, for example, 3,5,3'-triisopropyl-diphenyl-methane-4,4'-diamine and 3,5-diisopropyl-3'-ethyl-diphenylmethane-4,4'-diamine may also be used. Dialkyl-diphenylmethane diamines, such as 3,3'-diisopropyl-diphenylmethane-4,4'-diamine, may also be used, but are less preferred. However, mixtures of from about 45 to 65%, by weight, of 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diamine, from 27.5 to 17.5~, by weight, of 3,5,3',5'-tetraethyl-diphenylmetharle-
4,4'-diamine, and from 27.5 to 17.5%, by weight, of 3,5,3',5'-tetraisopropyl-diphenylmethane-4,4'-diamine are particularly preferred.
Mo-2439 ~P3~ ~0 , ~15-Another preferred group of aromatic diamines include dialkyl-toluene diamines and the isomeric r~ixtures thereof. Examp].e~ o these diamines include l-methyl-3,5-diisopropyl~2,4-diaminobenzene, l-methyl-3,5-diisopropyl-2,6-diaminobenzene, and preferably 1-methyl-3,5-diethyl-2,4-diaminobenzene and l~methyl-2,5-diethyl-2,6-diaminobenzene and mixtures thereof, preferably in r~tios of from 8:20 to 40:60.
Additional diamines which may be used include those of the 3,5-diamino-4-alkyl-benzoic acid alkyl ester series which correspond to the formula:
O
H2N ~ NH2 wherein X represents C1-C12 alkyl, preEerably methyl, ethyl, isopropyl OI- isobutyl, and R6 represents straight- or branched-chain Cl-C10 alkyl radicals, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, iso-amyl, _-hexyl, _-octyl, _-decyl or 2-ethylhexyl radicals.
The members in which X = CH3 and R = isopropyl, isobutyl or 2-ethylhexyl are particularly preferred.
The above-described diamines are to be used alone or in admixture with relatively high-molecular weight, substantially-linear polyhydroxyl compounds having molecular weights of from 400 to 12,000, preferably of from 400 to 5000. All the polyols which have already Mo-2439 ~3''~
-16~
~een listed in connection with the ~eparation of the NC0-prepolymers are included as relatively high-molecular weight polyhydroxyl compounds. Adipic acid/C2-C6 diol polyesters are again preferred according to the present invention.
As suita~le reactive aromatic diamines, the toluene diamines and isomer mixtures thereof, and particularly, the 4,4'-, 2,4'- and/or 2,2'-diphenyl-methane diamines (and isomer mixtures thereof), in the form of from 3 to 70~, by weight, preferably from
Mo-2439 ~P3~ ~0 , ~15-Another preferred group of aromatic diamines include dialkyl-toluene diamines and the isomeric r~ixtures thereof. Examp].e~ o these diamines include l-methyl-3,5-diisopropyl~2,4-diaminobenzene, l-methyl-3,5-diisopropyl-2,6-diaminobenzene, and preferably 1-methyl-3,5-diethyl-2,4-diaminobenzene and l~methyl-2,5-diethyl-2,6-diaminobenzene and mixtures thereof, preferably in r~tios of from 8:20 to 40:60.
Additional diamines which may be used include those of the 3,5-diamino-4-alkyl-benzoic acid alkyl ester series which correspond to the formula:
O
H2N ~ NH2 wherein X represents C1-C12 alkyl, preEerably methyl, ethyl, isopropyl OI- isobutyl, and R6 represents straight- or branched-chain Cl-C10 alkyl radicals, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, iso-amyl, _-hexyl, _-octyl, _-decyl or 2-ethylhexyl radicals.
The members in which X = CH3 and R = isopropyl, isobutyl or 2-ethylhexyl are particularly preferred.
The above-described diamines are to be used alone or in admixture with relatively high-molecular weight, substantially-linear polyhydroxyl compounds having molecular weights of from 400 to 12,000, preferably of from 400 to 5000. All the polyols which have already Mo-2439 ~3''~
-16~
~een listed in connection with the ~eparation of the NC0-prepolymers are included as relatively high-molecular weight polyhydroxyl compounds. Adipic acid/C2-C6 diol polyesters are again preferred according to the present invention.
As suita~le reactive aromatic diamines, the toluene diamines and isomer mixtures thereof, and particularly, the 4,4'-, 2,4'- and/or 2,2'-diphenyl-methane diamines (and isomer mixtures thereof), in the form of from 3 to 70~, by weight, preferably from
5 to 40%, by weight, and more preferably, from 10 to 35%, by weight, solutions thereof in relatively high-molecular ~eight polyhydroxyl compounds, may also be used according to the present invention. However, processing difficulties are encountered when reactive aromatic diamines, s~lch as diphenylmethane-4,4'-diamine, are used alone.
The NC0-prepolymers and the aromatic diamines are mixed according to known processes, for example, by metered mixing in chambers equipped with stirrers or by high pressure injection mixing in known elastomer casting machines.
EXAMPLES
The same apparatus and the same operational ~5 conditions for casting were used in all the Examples and Comparative Examples.
Equipment:
Toothed-weel metering pump and mixing head equipped with a 5000 r.p.m. spiked stirrer.
Processinq temperatures:
NC0-prepolymer 80C ~ Both components were metered o C and mixed in an NCO/(OH+)NH~-Chain extender 80 C J ratio as given in the examp~es.
(dlamine etc.) The reaction mixture is cast in open molds (test panels).
Mo-2439 3~
-17~
.. . .. .... .... .. . . . .. . .. . .. . . ..
Examples 1 and 2 rnot accordin~ to the pxesent inventionl:
5how the lo~er quality and the poor solidificati~n ~ehavior of the elastomers ~hich were prep~red using only -tetra-alkyl-diphenylmethane diisoc~anates as the isocyanate component (see Table 1) EXAMoeLE 1 (Comparative~
. .
Synthesis of the NCO-prepolymer 2000 g of an adipic acid ethylene glycol polyester diol having a molecular weight of 2000 are reacted with 1~ 832 g of a tetra-alkyl-diphenylmethane diisocyanate mixture consisting of:
50~, by weight, OCN ~ ~ ~ H2 ~ ~NCO
25%, by weight, OCN~ H2 ~ NCO
25%, by ~eight, OCIL~ ~ CH2 - ~ NCO
to produce an NCO~prepolymer containing 3.4%, by wetght, - of NCO.
Preparation of the elastomer A hot melt at about 60C of a chain-lenythening agent consisting of:
Mo-2439 50%, by weight, 25%, by weight, 25%, by weight, is metered into the mixing head with the NCO-prepolymer and the reaction takes place in an NCO:NH2 ratio of 1.05:1. A product is obtained which is still of such a waxy and brittle nature, even after being heated for 10 hours at 100°C, that a mechanical test could not be performed on the elastomer.
EXAMPLE 2 (Comparative) 1500 g of a polypropylene oxide ether diol of molecular weight 1500 are reacted with 820 g of the tetra-alkyl-diphenylmethane diisocyanate mixture according to Example 1 to produce an NCO-prepolymer containing 3.7%, by weight, of NCO. The reaction between the NCO-prepolymer and the chain-lengthening agent according to Example 1 takes place in an NCO:NH2 ratio of 1.05:1. The resulting elastomers are still of a waxy brittle nature after 2 hours at 100°C, and exhibit only moderate properties.
o EXAMPLES 3 to g -~Examples 3 and 4 not according to -the present invention) (Examples 5-9 according to the present invention) These Examples demonstrate the advantage of the blending operation with tetra-alkyl~diisocyanato-diphenylmethane and the use of different chain-lengthening agents (Table 1).
The base prepolymer used is prepared by reacting one mol of a polyester diol of adipic acid and ethylene glycol having a molecular weight of 2000 with 2 mols of 2,4-toluene diisocyanate to produce an NCO-prepolymer containing 3.5%, by weight, of NCO.
XAMPLE 3 (Comparative) The base prepolymer is cast with the chain-lengthening diamine mixture of Example 1 in a ratio ofNCO:NH2 of 1.05:1. Heating time of the cast elastomer = 10 hours at 80C.
EXAMPLE 4 (Comparative) To the base prepolymer is added an isocyanate mixture to give a total NCO content of 4.5~. The isocyanate mixture comprises 40%, by weight, of 4,4'-diisocyanato-diphenylmethane and 60%, by weight, of 2,4'-diisocyanato-diphenylmethane. Processing takes place using the chain-lengthening diamine of Example 1 with an NCO:NH2 ratio of 1.05:1. The moldings are heated for 10 hours at 80C.
EXAl~PLE 5 To the base prepolymer is added an isocyanate mixture to give an NCO content of 4.7~, by weight.
The isocyanate mixture is the tetra-alkyl-diphenylmethane diisocyanate mixture correspondiny to the mixture of Example 1. The diamine mixture according to Example 1 is used as the chain-lengthening a~ent in an NCO:~H2 ratio of 1.05:1 and the molding is subsequently heated for 10 hours at 80C.
Mo-2439 3~
_2~-EXAMPLES 6 to g To the base prepolymer is added an isocyanate to give an NCO content of 4.5%. The isocyanate added is 3, 3 ', 5,5'-tetraethy1-~4,4'~diisocyanato-diphenylmethane.
This blend is reacted with the following chain-lengthening agents in an NCO:NH2 ratio of 1.05:1.
EXAMPLE 6: Diamine mixture of Example 1 EXAMPLE 7:
H 2N ~ -CH2 ~H 2 C H
EXAMPLE 8: C,2~5 ~C2 CH2-CH- (CH2) 3-CH3 l O
/'~1~\
EXAMPLE 9:
. C2H5~ CH3 C2H5 ~ 2 5 ~_ ~Gl ~
H2N `~ NH2 CH3 2 The moldings are subsequently heated for 10 hours at 80C.
Mo-24 3 9 ~3~
The casting time (pot life~ in these ~.xample~ in relatively short (Example 3~ or is extremely short when the blending opera~ion is carried out using diphenyl-methane diisocyanate ni~tures (Example 4). In contrast thereto, the casting time, when the diisocyanates according to the present invention are used, is sufficiently long without impairing the solidification times. The elastomers produced exhibit a good strength and good elongation, a good elas~icity and a very good tear propagation resistance.
Mo-2439 Unable to recognize this page.
~33~4~
~, -23~ .' EXAMPLES 10 to 13 These Examples sho~ the effect of the blending opera-tion using tetraethyl-4,4'-diisocyanato-diphenyl-methane, and the use of solutions of the chain-lengthening diamines in a relatively high molecular weight poly-hydroxyl compound (Table 2) in the casting process.
Base prepolymer:
- Adipic acid polyester diol of molecular weight 2000 based on butane diol-4,4/ethylene glycol (diol mol ratio 1:1).
- Toluene diisocyanate isomer mixture (65% 2,4-isomer ~ 35% 2,6-isomer~
mol. ratio of toluene diisocyanate:polyester = 2.0:1 NCO content of NCO-prepolymer = 3.5%.
EXAMPLE 10 _ omparative) To thebase prepol.ymer is added diisocyanato-diphenylmethane (60% 4,4'-isomer + 40% 2,4'-isomer) to yield an NCO content of 4.5%.
Chain-lenghtening (casting) is carried out using a mixture o;
30%, by weight, H2N- ~ C 2 ~ -NH2 and C2H5 C2~15 70%, by weight, of the polyadipate used in the base prepolymer.
NCO:OH~NH2 ratio = 1.05:1 25 After-heating of the ela5tomer: 10 hours at 80DC.
Mo- 2439 ~3~
~24-EXAMPLES 11 to 13 To the base prepolymer is added 3,3',5,5'-tetra-ethyl-4,4'-diisocyanato-diphenylmethane to give an NCO
eontent of 4.5%. This ~lend is processed with solutions of 30 parts, by weight, of diamine in 70 parts, by weight, of the polyadipate used for the prepolymer in an NCO:OH+NH2 ratio of 1.05:1. These diamine solutions contained diaza-bicyclo-octane as catalyst. The following di~mines were used:
10 Example 11: H2N - ~ CH2 ~NH2 Catalysis: 0.3~, by weight, of diazabieyclo-oetane, ealculated on the diamine solution.
Example 12.
C2H5 C~3 C2H5 ~ - C2 5 70% ~ 30~ ,, Catalysis: 0.3~, by weight, of diazabicyclo-octane, caleulated on the diamine solution.
Mo-2439 9 3 C3 L~ ~
.
Example 13 H2N~ CH2~NHz Catalysis: 0.15~, by weight, of diaza-bicyclo-octane, calculated S on the diamine solution.
After-heating conditions in Examples ll to 13: 10 hours at 80C.
Comparative Example lO provides a very long consol-dation time with a very short casting time.
In Examples ll and 12, very fast consolidation times are achieved with a favorable casting time. Example 13 shows that, according to the present invention, reactive amines, such as 4,4'-diamino~diphenylmethane, in the form of the solutions thereof in relatively high molecular weight polyhydroxyl compounds may also be processed.
Mo-2439 EXAMPLES 14 and 15 -These Examples show that the effect of the ~lending operation with tetra-alkyl-4,4'-diisocyanato-diphenylmethane is still maintained into higher NCG
contents (Table 2).
Base prepolymer:
Polypropylene glycol of molecular weight 1500 is reacted with toluene diisocyanate (65% 2,4-isomer + 35%
2,6'-isomer) to produce an NCO-prepolymer containing 47% of NCO.
EXAMPLE 14 ~Comparat _e) To the base prepolymer is added diphenylmethane diisocyanate (60~ 4,4'-isomer + 40% 2,4'-isomer) to a resulting NCO content of 6.0%.
The chain-lengthening diamine mixture according to Example 1 is then added to the prepolymer in an NCO:NH2 ratio of 1.05:1.
To the base prepolymer is added 3,3',5,5'-tetraethyl-4,4'-diisocyanato-diphenylmethane to give an NCO content of 6.0%.
The diamine mixture of Example 1 is then added to the prepolymer in an NCOoNll2 ratio of 1.05:1.
After-heating conditions in both Examples: 10 hours at 80C.
Comparative Example 14 clearly shows shorter, impracticable casting times. On the other hand, there are obvious processing advantages of Example 15 which is according to the present invention.
Mo-2439 Unable to recognize this page.
~30~
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 therein by those skilled in ~he art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo-2439
The NC0-prepolymers and the aromatic diamines are mixed according to known processes, for example, by metered mixing in chambers equipped with stirrers or by high pressure injection mixing in known elastomer casting machines.
EXAMPLES
The same apparatus and the same operational ~5 conditions for casting were used in all the Examples and Comparative Examples.
Equipment:
Toothed-weel metering pump and mixing head equipped with a 5000 r.p.m. spiked stirrer.
Processinq temperatures:
NC0-prepolymer 80C ~ Both components were metered o C and mixed in an NCO/(OH+)NH~-Chain extender 80 C J ratio as given in the examp~es.
(dlamine etc.) The reaction mixture is cast in open molds (test panels).
Mo-2439 3~
-17~
.. . .. .... .... .. . . . .. . .. . .. . . ..
Examples 1 and 2 rnot accordin~ to the pxesent inventionl:
5how the lo~er quality and the poor solidificati~n ~ehavior of the elastomers ~hich were prep~red using only -tetra-alkyl-diphenylmethane diisoc~anates as the isocyanate component (see Table 1) EXAMoeLE 1 (Comparative~
. .
Synthesis of the NCO-prepolymer 2000 g of an adipic acid ethylene glycol polyester diol having a molecular weight of 2000 are reacted with 1~ 832 g of a tetra-alkyl-diphenylmethane diisocyanate mixture consisting of:
50~, by weight, OCN ~ ~ ~ H2 ~ ~NCO
25%, by weight, OCN~ H2 ~ NCO
25%, by ~eight, OCIL~ ~ CH2 - ~ NCO
to produce an NCO~prepolymer containing 3.4%, by wetght, - of NCO.
Preparation of the elastomer A hot melt at about 60C of a chain-lenythening agent consisting of:
Mo-2439 50%, by weight, 25%, by weight, 25%, by weight, is metered into the mixing head with the NCO-prepolymer and the reaction takes place in an NCO:NH2 ratio of 1.05:1. A product is obtained which is still of such a waxy and brittle nature, even after being heated for 10 hours at 100°C, that a mechanical test could not be performed on the elastomer.
EXAMPLE 2 (Comparative) 1500 g of a polypropylene oxide ether diol of molecular weight 1500 are reacted with 820 g of the tetra-alkyl-diphenylmethane diisocyanate mixture according to Example 1 to produce an NCO-prepolymer containing 3.7%, by weight, of NCO. The reaction between the NCO-prepolymer and the chain-lengthening agent according to Example 1 takes place in an NCO:NH2 ratio of 1.05:1. The resulting elastomers are still of a waxy brittle nature after 2 hours at 100°C, and exhibit only moderate properties.
o EXAMPLES 3 to g -~Examples 3 and 4 not according to -the present invention) (Examples 5-9 according to the present invention) These Examples demonstrate the advantage of the blending operation with tetra-alkyl~diisocyanato-diphenylmethane and the use of different chain-lengthening agents (Table 1).
The base prepolymer used is prepared by reacting one mol of a polyester diol of adipic acid and ethylene glycol having a molecular weight of 2000 with 2 mols of 2,4-toluene diisocyanate to produce an NCO-prepolymer containing 3.5%, by weight, of NCO.
XAMPLE 3 (Comparative) The base prepolymer is cast with the chain-lengthening diamine mixture of Example 1 in a ratio ofNCO:NH2 of 1.05:1. Heating time of the cast elastomer = 10 hours at 80C.
EXAMPLE 4 (Comparative) To the base prepolymer is added an isocyanate mixture to give a total NCO content of 4.5~. The isocyanate mixture comprises 40%, by weight, of 4,4'-diisocyanato-diphenylmethane and 60%, by weight, of 2,4'-diisocyanato-diphenylmethane. Processing takes place using the chain-lengthening diamine of Example 1 with an NCO:NH2 ratio of 1.05:1. The moldings are heated for 10 hours at 80C.
EXAl~PLE 5 To the base prepolymer is added an isocyanate mixture to give an NCO content of 4.7~, by weight.
The isocyanate mixture is the tetra-alkyl-diphenylmethane diisocyanate mixture correspondiny to the mixture of Example 1. The diamine mixture according to Example 1 is used as the chain-lengthening a~ent in an NCO:~H2 ratio of 1.05:1 and the molding is subsequently heated for 10 hours at 80C.
Mo-2439 3~
_2~-EXAMPLES 6 to g To the base prepolymer is added an isocyanate to give an NCO content of 4.5%. The isocyanate added is 3, 3 ', 5,5'-tetraethy1-~4,4'~diisocyanato-diphenylmethane.
This blend is reacted with the following chain-lengthening agents in an NCO:NH2 ratio of 1.05:1.
EXAMPLE 6: Diamine mixture of Example 1 EXAMPLE 7:
H 2N ~ -CH2 ~H 2 C H
EXAMPLE 8: C,2~5 ~C2 CH2-CH- (CH2) 3-CH3 l O
/'~1~\
EXAMPLE 9:
. C2H5~ CH3 C2H5 ~ 2 5 ~_ ~Gl ~
H2N `~ NH2 CH3 2 The moldings are subsequently heated for 10 hours at 80C.
Mo-24 3 9 ~3~
The casting time (pot life~ in these ~.xample~ in relatively short (Example 3~ or is extremely short when the blending opera~ion is carried out using diphenyl-methane diisocyanate ni~tures (Example 4). In contrast thereto, the casting time, when the diisocyanates according to the present invention are used, is sufficiently long without impairing the solidification times. The elastomers produced exhibit a good strength and good elongation, a good elas~icity and a very good tear propagation resistance.
Mo-2439 Unable to recognize this page.
~33~4~
~, -23~ .' EXAMPLES 10 to 13 These Examples sho~ the effect of the blending opera-tion using tetraethyl-4,4'-diisocyanato-diphenyl-methane, and the use of solutions of the chain-lengthening diamines in a relatively high molecular weight poly-hydroxyl compound (Table 2) in the casting process.
Base prepolymer:
- Adipic acid polyester diol of molecular weight 2000 based on butane diol-4,4/ethylene glycol (diol mol ratio 1:1).
- Toluene diisocyanate isomer mixture (65% 2,4-isomer ~ 35% 2,6-isomer~
mol. ratio of toluene diisocyanate:polyester = 2.0:1 NCO content of NCO-prepolymer = 3.5%.
EXAMPLE 10 _ omparative) To thebase prepol.ymer is added diisocyanato-diphenylmethane (60% 4,4'-isomer + 40% 2,4'-isomer) to yield an NCO content of 4.5%.
Chain-lenghtening (casting) is carried out using a mixture o;
30%, by weight, H2N- ~ C 2 ~ -NH2 and C2H5 C2~15 70%, by weight, of the polyadipate used in the base prepolymer.
NCO:OH~NH2 ratio = 1.05:1 25 After-heating of the ela5tomer: 10 hours at 80DC.
Mo- 2439 ~3~
~24-EXAMPLES 11 to 13 To the base prepolymer is added 3,3',5,5'-tetra-ethyl-4,4'-diisocyanato-diphenylmethane to give an NCO
eontent of 4.5%. This ~lend is processed with solutions of 30 parts, by weight, of diamine in 70 parts, by weight, of the polyadipate used for the prepolymer in an NCO:OH+NH2 ratio of 1.05:1. These diamine solutions contained diaza-bicyclo-octane as catalyst. The following di~mines were used:
10 Example 11: H2N - ~ CH2 ~NH2 Catalysis: 0.3~, by weight, of diazabieyclo-oetane, ealculated on the diamine solution.
Example 12.
C2H5 C~3 C2H5 ~ - C2 5 70% ~ 30~ ,, Catalysis: 0.3~, by weight, of diazabicyclo-octane, caleulated on the diamine solution.
Mo-2439 9 3 C3 L~ ~
.
Example 13 H2N~ CH2~NHz Catalysis: 0.15~, by weight, of diaza-bicyclo-octane, calculated S on the diamine solution.
After-heating conditions in Examples ll to 13: 10 hours at 80C.
Comparative Example lO provides a very long consol-dation time with a very short casting time.
In Examples ll and 12, very fast consolidation times are achieved with a favorable casting time. Example 13 shows that, according to the present invention, reactive amines, such as 4,4'-diamino~diphenylmethane, in the form of the solutions thereof in relatively high molecular weight polyhydroxyl compounds may also be processed.
Mo-2439 EXAMPLES 14 and 15 -These Examples show that the effect of the ~lending operation with tetra-alkyl-4,4'-diisocyanato-diphenylmethane is still maintained into higher NCG
contents (Table 2).
Base prepolymer:
Polypropylene glycol of molecular weight 1500 is reacted with toluene diisocyanate (65% 2,4-isomer + 35%
2,6'-isomer) to produce an NCO-prepolymer containing 47% of NCO.
EXAMPLE 14 ~Comparat _e) To the base prepolymer is added diphenylmethane diisocyanate (60~ 4,4'-isomer + 40% 2,4'-isomer) to a resulting NCO content of 6.0%.
The chain-lengthening diamine mixture according to Example 1 is then added to the prepolymer in an NCO:NH2 ratio of 1.05:1.
To the base prepolymer is added 3,3',5,5'-tetraethyl-4,4'-diisocyanato-diphenylmethane to give an NCO content of 6.0%.
The diamine mixture of Example 1 is then added to the prepolymer in an NCOoNll2 ratio of 1.05:1.
After-heating conditions in both Examples: 10 hours at 80C.
Comparative Example 14 clearly shows shorter, impracticable casting times. On the other hand, there are obvious processing advantages of Example 15 which is according to the present invention.
Mo-2439 Unable to recognize this page.
~30~
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 therein by those skilled in ~he art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo-2439
Claims (9)
1. A process for the production of polyurethane urea products by reacting (A) an isocyanate blend comprising (a) an NCO-prepolymer which is substantially monomer-free and which is produced by reacting sub-stantially linear, relatively high molecular weight polyhydroxyl compounds which have molecular weights of from 400 to 12,000, with toluene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate or a combination of these diisocyanates, in an NCO:OH ratio of greater than 1.1:1, and (b) from 0.1 to 25%, by weight, of diphenyl-methane diisocyanates which are tetra-alkyl-substituted in o-positions to the NCO-groups which correspond to the general formula:
wherein R1, R2, R3 and R4, which may be the same or different represent straight- or branched-chain alkyl radicals having from 1 to 4 carbon atoms, with (B) chain-lengthening aromatic diamines in quantities of from 0.8:1 to 1.2:1 of isocyanate to isocyanate-reactive groups to prepare said polyurethane urea products.
wherein R1, R2, R3 and R4, which may be the same or different represent straight- or branched-chain alkyl radicals having from 1 to 4 carbon atoms, with (B) chain-lengthening aromatic diamines in quantities of from 0.8:1 to 1.2:1 of isocyanate to isocyanate-reactive groups to prepare said polyurethane urea products.
2. A process according to Claim 1, characterized in that the chain-lengthening aromatic diamines comprise diamines taken from the group consisting of members from the series of di- to tetra-alkyl-diphenylmethane diamines corresponding to the general formula:
wherein R1 to R4 are as defined in Claim 1, and wherein R2 and R4 may also represent H;
members from the series of dialkyl-toluene diamines corresponding to the general formulae:
wherein R5, which may be the same or different, represents straight- or branched-chain C1-C4 alkyl radicals;
members from the series of aromatic diamines of 3,5-diamino-4-alkyl-benzoic acid alkyl esters corresponding to the general formula:
wherein X represents C1-C12 alkyl, and R6 represents straight- or branched-chain C1-C10 alkyl radicals;
solutions of reactive aromatic diamines without alkyl groups in the vicinity of each amino group and without deactivating substituents, dissolved in relatively high molecular weight polyhydroxyl compounds; and combinations of these diamines.
wherein R1 to R4 are as defined in Claim 1, and wherein R2 and R4 may also represent H;
members from the series of dialkyl-toluene diamines corresponding to the general formulae:
wherein R5, which may be the same or different, represents straight- or branched-chain C1-C4 alkyl radicals;
members from the series of aromatic diamines of 3,5-diamino-4-alkyl-benzoic acid alkyl esters corresponding to the general formula:
wherein X represents C1-C12 alkyl, and R6 represents straight- or branched-chain C1-C10 alkyl radicals;
solutions of reactive aromatic diamines without alkyl groups in the vicinity of each amino group and without deactivating substituents, dissolved in relatively high molecular weight polyhydroxyl compounds; and combinations of these diamines.
3. A process according to Claim 2, characterized in that the chain-lengthening diamines are dissolved in polyhydroxyl compounds which have molecular weights of from 400 to 12,000.
4. A process according to Claim 1, characterized in that catalysts and other known additives are used in preparing the elastomers.
5. A process according to Claim 1, characterized in that said isocyanate blend comprises (a) a substanti-ally monomer-free NCO-prepolymer produced from sub-stantially linear, relatively high molecular weight polyhydroxyl compounds having a molecular weight of from 400 to 6000, and toluene diisocyanate in an NCO:OH ratio of from 1.1:1 to 2.1:1 and (b) from 0.1 to 25%, by weight, of diphenylmethane diisocyanates which are tetra-alkyl-substituted in o-positions to the NCO groups, said blend containing from 4 to 8%, by weight, of NCO
groups.
groups.
6. A process according to Claim 1, characterized in that diols having a molecular weight of from 62 to 399 are combined with the relatively high molecular weight polyhydroxyl compounds for preparing the NCO-prepolymer.
7. A process according to Claim 1, characterized in that a product mixture of from 45 to 65%, by weight, of 3,5-diethyl-3',5'-diisopropyl-diphenylmethane-4,4'-diisocyanate, from 17.5 to 27.5%, by weight, of 3,5,3',5'-tetraethyl-diphenylmethane-4,4'-diisocyanate, and from 17.5 to 27.5%, by weight, of 3,5,3',5'-tetra-isopropyl-diphenylmethane-4,4'-diisocyanate is used as the diphenylmethane diisocyanates which are tetra-alkyl-substituted in the o-position to the NCO groups.
8. A process according to Claim 2, characterized in that the isocyanate blend is reacted with chain-lengthening aromatic diamines from the series of tetra-alkyl-diphenylmethane diamines and dialkyl-substituted toluene diamines, wherein, R1 to R4 represent ethyl and isopropyl groups and R5 represents ethyl and isopropyl groups in the formulae.
9. A process according to Claim 3, characterized in that solutions of diphenylmethane diamines in relatively high molecular weight polyhydroxyl compounds are used as the chain-lengthening diamines.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823200425 DE3200425A1 (en) | 1981-01-12 | 1982-01-09 | METHOD FOR PRODUCING A ZINCOXIDE FILM |
| DEP32004L2.5 | 1982-01-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1193040A true CA1193040A (en) | 1985-09-03 |
Family
ID=6152782
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000418963A Expired CA1193040A (en) | 1982-01-09 | 1983-01-06 | Process for the production of polyurethane urea products |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1193040A (en) |
-
1983
- 1983-01-06 CA CA000418963A patent/CA1193040A/en not_active Expired
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