DE2416679A1 - POLYISOCYANATE - Google Patents

Description

"Polyisocyanates"

Priority : April 5, 1973, UK No. 16293/73

The invention relates to mixed methylene bridges containing polycyclohexylene polyisocyanates, to a process for the preparation of such mixed polyisocyanates and the use of the same for the production of polyurethanes.

According to the invention, mixed polycyclohexylene polyisocyanates containing methylene bridges are prepared which essentially from mixtures of diisocyanates and triisocyanates and polyisocyanates of higher functionality. "

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Polycyclohexylene polyisocyanates containing methylene bridges are compounds that contain two or cyclohexyl rings, each of which has an isocyanate group and the rings are connected to one another by methylene bridges, d. The simplest terms of this series are 2,2'-, 2,4'- and ^ - ^ '- diisocyanato-dicyclohexylraethane dex "formula

OCN

H \ _ NCO

There are also a number of isomeric methylene bridged tricyclohexylene triisocyanates and the formula of such a typical isomer is the following:

OCN— (H.

CH.

v_y

NCO

NCO

The polycyclohexylene polyisocyanates containing methylene bridges so have the general formula

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NCO

NCO

where η is 1 or a larger number.

The present invention relates to mixtures which consist essentially entirely of such polyisocyanates. In the production of such polyisocyanate mixtures by-products are formed by phosgenation processes, as they occur in all phosgenation processes and the term "essential" is to be understood in such a way that the compositions of matter according to the invention are in which such by-products are present.

Polycyclohexylene polyisocyanate compositions of matter containing methyl bridges can be obtained by phosgenating a mixture of polycyclohexylenepolyamines containing methylene bridges are prepared, the amines being converted into the corresponding isocyanates.

According to a further feature of the invention is thus also proposed a process for the preparation of mixed polycyclohexylene polyisocyanates containing methylene bridges, which consists essentially of a mixture of diisocyanate, triisocyanates and higher polyisocyanates exist by phosgenating a mixture of polycyclohexylenepolyamines containing methylene bridges.

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Those to be used as starting materials in the above process Polyamine mixtures can through. Ring reduction of the mixed, methylene-bridged polyphenyl polyamines which are obtained by condensation of aniline with formaldehyde.

The production of mixtures of methylene bridges Polypheny! Polyamines are well known. she • are made by condensing aniline with formaldehyde either in the presence of strong acids, such as hydrochloric acid or "other catalysts, prepared the condensate from diamines, triamines and polyamines with higher functionality consists. Typical working methods are the German patent application P 23 01 554.5 as well as in the GB-PSs 1 298 258, 1 229 695, 1 229 236, 1 288 937, 1 229 561 and 1 228 495.

These compounds correspond to the general formula

NH

-CH,

_Y n-1

NH.

where η is 1 or a larger number.

A large number of polyamine mixtures of this type can be produced by condensing aniline with formaldehyde will. So it is, for example, by suitable setting of the aniline / formaldehyde ratio and / or of the aniline / acid ratio possible to produce products which contain different amounts of diamines and contain higher polyamines and it is therefore possible

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Manufacture products that contain a large proportion of isomeric diamines or products with a lower proportion Proportion of isomeric diamines and correspondingly higher proportions of triamine or polyamines of higher functionality. In general, j-e is higher than the aniline / formal de hyd ratio, the greater the amount of diamine in the product.

Differences in the "ratio of particular amines in that Aniline / formaldehyde condensation products show up in corresponding differences in the ratio of diisocyanate, Triisocyanate and higher polyisocyanates in the methylene bridges derived therefrom Polycyclohexylene polyisocyanates. Although usable methylene bridges containing polycyclohexylene polyisocyanates can be produced from aniline / formaldehyde condensates, which 'differ from any proportions of aniline / Formaldehyde, which are known for the condensation reaction, is preferred to derive aniline / formaldehyde condensates to use where an aniline to formaldehyde ratio from 1.4: 1 to 6: 1 is present.

The mixture of polyphenyl polyamines containing methylene bridges, which are caused by the aniline / formaldehyde condensation is preferably reduced to a mixture by hydrogenation in the presence of a catalyst of polycyclohexylenepolyamines having methylene bridges.

Condensation treatments to reduce aromatic amines to the corresponding cycloalkylamines are general known and they can be used to reduce the polyphonyl polyamines containing methylene bridges to the methylene bridges containing polycyclohexylenepolyamines can be used.

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The hydrogenation is expediently carried out in a suitable plant, for example in an autoclave equipped with a stirrer at a temperature of 180 to 250 ° 0, preferably at 190 to 210 ⁰ C, and at a pressure of 50 to 900 atmospheres, preferably 150 to 250 atmospheres. A solvent such as water, cyclohexane, dioxane, methanol or propanol can be used as desired. The catalysts that can be used are palladium metal, palladium-on-carbon, ruthenium oxide, finely divided cobalt metal, cobalt oxide, nickel metal and nickel oxide. It is preferred to use a composite catalyst consisting of cobalt oxide, anhydrous sodium carbonate and lime , the solvent being used in the absence of water.

The phosgenation can be carried out in any of the usual ways. This can be carried out batchwise, semicontinuously or continuously. The aqueous interfacial technique, which is suitable for the production of aliphatic: isocyanate, as described in GB-PS 1,152,877, is also suitable. A continuous or semi-continuous procedure is preferred. In the former case, a solution of the polyamine in a suitable solvent, such as toluene, xylene, a chlorinated hydrocarbon, an organic ester or an organic ether, is ^{stirred with phosgene in a first stage in a reactor at 20 to 50 o} 0. The overflow from this reactor passes into a second reactor provided with a stirrer, which is kept at a temperature of 70 to 90 ⁰ C and from there into a third reactor, which is optionally also equipped with a stirrer and at a temperature of 100 to 120 ° C is helped. A fourth reactor can also be used here

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which works at a similar or higher temperature. The diluted crude polyisocyanate is degassed and concentrated using a conventional work-up plant, such as columns provided with pacification, climbing film and thin film evaporators.

In the semi-continuous operation of the overflow passes from the first reactor stage to a second stage reactor, which is maintained at 70 to 100 ⁰ C. When this reactor is full, the supply from the first reactor is interrupted and the stirring treatment is continued in the second reactor until the contents of the same are clear and the phosgenation is carried out to the end. The diluted crude polyisocyanate is worked up in the usual way.

In addition to converting the amine groups into isocyanate groups, the phosgenation also leads to certain Side reactions, however, are only minor. The main side reaction that takes place is the formation of urea groups by reaction of isocyanate groups, which are already non-phosgenated Amino groups have been formed. The amount of by-products formed is about 5 to 10 wt. of the total product.

It has been found that there is no need to purify the methylene-bridged polycyclohexylene polyamines formed by reduction of the aniline / formaldehyde condensation product before they are subjected to the phosgenation treatment. It has been found that small amounts of, for example, 5 to 20 % of non-reduced aromatic rings and, as a result, aromatic isocyanate fractions can be permitted in the final compositions and the properties of the polycyclohexylene polyisocyanates containing methylene bridges

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do not significantly affect cyanates. In particular, affect they do not affect the light resistance of the polyurethane products, which differ from the methylene bridges having polycyclohexylenepolyisoxyanate products.

The mixtures of polycyclohexylene polyisocyanates containing methylene bridges, especially those with a

te

high diisocyanate content can be used to produce purified 4-, 4- '-diisocyanatodicyclohexlymethane Purification processes are used which include distillation and / or crystallization. It is preferred to use the mixture of polyisocyanates obtained by phosgenating the polyamines without purification can be obtained because it provides a low cost polyisocyanate, which for many Purposes' is useful, excluding the expensive, commercially available aliphatic polyisocyanates. Thus, mixtures of methylene bridges can be used Polycyclohexylene polyisocyanates are used to produce polyurethanes by known methods, in which the polyisocyanates are reacted with compounds which have two or more isocyanate-reactive groups, in particular contain hydroxyl groups. The polyurethanes can, for example, in the form of homogeneous elastomers, Cellular products of all kinds, surface coverings and adhesives are present. They are particularly valuable for the manufacture of the following products:

(1) Clear and pigment-containing surface coatings from various types, especially pastel shades, if such are desired;

(2) seamless flooring while avoiding a disadvantage known in the art as the amber-like effect and which occurs when aromatic polyiso-

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cyanate is worked;

(3) - non-decolorizing adhesives for use on non-woven fabrics Textile materials, clothing and wear and tear underlying clothing of various types;

(4) one-piece skin-like shaped pieces
of superior lightfastness. For this purpose can
only part of the polycyclohexylene polyisocyanate can be used in conjunction with another aliphatic or aromatic polyisocyanate.

(5) elastomers with good resistance to exposure to light and heat;

(G) Polyurethanes for use in powder coating technology.

Polycyclohexylene polyisocyanate mixtures containing methylene bridges and containing 35 to 85 wt.
Diisocyanatodicyclohexylmethanes, tricyclohexylene triisocyanates containing 5 to 35 % methylene bridges, together with polycyclohexylene polyisocyanates containing higher functionality, methylene bridges are preferred.

As already mentioned, the compositions of matter of the invention include mixtures of methylene bridges
Polycyclohexylene polyisocyanates .ein, / which 5 to 20 #, ie from 1 in 20 to 1 in 5 of the rings still have an aromatic character. Such compositions of matter close
Mixtures of polycyclohexylene polyisocyanates containing methylene bridges with mixed poly (mixed cyclohexylene / phenyl) polyisocyanates containing methylene bridges
and small amounts of polyphenyl polyisocyanates containing methylene bridges, the latter being by
Phosgenation of polyphenyl polyamines having methylene bridges are obtained in which one of the aromatic rings has undergone a reduction. Poly (mixed cyclohexyl / phenyl) polyiso-

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Cyanates are made by the phosgenation of polyamines in which at least one of the aromatic rings remains unreduced. Such compositions of matter are particularly useful, depending on the end use.

The invention also relates to mixtures of methylene-bridged poly (cyclohexyl / phenyl) polyisocyanates, i. Mixtures in which at least one Sing in each molecule is reduced and no longer in the aromatic state is present.

The invention is explained in more detail in the following examples, in which the parts and percentages refer to the Relate to weight, if nothing else is noted.

example 1

558 parts of aniline, 291 parts of 35 # hydrochloric acid (w / w) and 4-57 parts v / ater were mixed together and the temperature set to 50 ° G. The mixture became vigorous stirred and 225 parts of a 36 show aqueous I'ormaldehyde solution were added over 1 hour. During this time care was taken to keep the temperature Does not exceed 55 ° C. After adding the formaldehyde "was the reaction mixture to 95 g within 30 minutes increased and held at this temperature for 95 minutes.

The reaction mixture was then neutralized by adding an excess of sodium hydroxide solution and the polyamine, which was in the form of a pale brown-colored oil, was washed free of the salt and the excess of alkali. It was then dehydrated by heating to a temperature of about 150 ° C. under reduced pressure. The methylene- bridged polyphenyl polyamine fabric composition contained approximately 65% diamine, 15 x $ triamines and

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about 20 % polyamines of the formula

BRA.

CH.

where η is 3 or a larger number.

Polyphenylpolyamines containing 187 parts of methylene bridges, which were prepared in the above-described manner, were suspended in 1000 parts of water and 1 part of ruthenium dioxide was added. The mixture was then ^{hydrogenated at 200 °} C. and a pressure of 140 to 211 kg / cm for 8 hours in a circulating Bergius pressure vessel.

After 8 hours, the reaction mass was cooled, the excess hydrogen was drained off and the suspension was filtered. The water and a small amount of volatile by-products were removed by evaporation under reduced pressure. 148 parts of polycyclohexylenepolyamines containing methylene bridges were obtained, which corresponds to a yield of 75 % of theory.

Example 2

250 parts of polyphenyl polyamines containing methylene bridges, produced according to example 1, 6.25 parts of cobalt oxide (C02O7) 15 parts of sodium carbonate and 15 parts of calcium oxide were added hydrogenated according to example 1. After 8 hours, the reaction mass was diluted with 1000 parts of methanol and the Suspension filtered. The methanol and volatiles were reduced by evaporation Pressure removed. 227 parts having methylene bridges

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Polycyclohexylenepolyamines were obtained, which corresponds to a yield of 70 % of theory.

Example 3 .

Polyphenylenepolyamines containing 26 parts of methylene bridges, 250 parts of isopropanol and 5 parts of 5 % palladium-on-carbon were hydrogenated according to Example 1. After δ hours the suspension was filtered and the isopropanol and volatile impurities were removed by evaporation under reduced pressure. 240 parts of polycyclohexylenepolyamines containing methylene bridges were obtained, which corresponds to a yield of 85 % of theory.

example M-

1 50 parts of methylene-bridged Polycyclohexylenpolyamine prepared according to the procedure of Example 2 was dissolved in 1350 parts of monochlorobenzene and the solution was continuously supplied together with phosgene a flask equipped with a stirrer reactor, maintained at a temperature between 10 and 5O ⁰ C

t
became. The reaction mass overflowed into a second reactor equipped with a stirrer, which was kept at a temperature of 70 to 90 ⁰ C. When all of the amine had been added to the system, the temperature of the second reactor was increased to 120 ^° C. and the reaction was continued at this temperature for 2 to 3 hours.

After degassing, the solvent was removed under reduced pressure. The residue was diluted with 50 parts of monochlorobenzene and heated ^{to 190 °} C. at a rate of 1 liter per minute with thorough stirring and an addition of nitrogen. This temperature was maintained for 15 minutes and the solution then rapidly cooled to room temperature. The residue consisted essentially of methylene bridges

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pointing polycyclohexylene polyisocyanates, which were obtained in an amount of 168 parts, which corresponds to a yield of 90 % . In an analysis of the product showed that this 26.6 ° /> isocyanate groups per molecule and. ^ 1.5% of hydrolyzable chlorine contained, if the examination according to the ASTM method was performed.

Example 5

Polycyclohexylenepolyamines containing 21 parts of methylene bridges were added to 2f> 0 parts of water and the solution was stirred and heated to 80.degree. The 'mixture was then cooled slowly with stirring to 4-0 ⁰ C and 64 parts of anhydrous sodium carbonate dissolved in I50 parts v / ater was added. The mixture was then ^{cooled from the outside to 0} ° C. and the stirring treatment was interrupted.

A solution of 60 parts of phosgene in 200 parts of toluene was carefully added to form a top layer. The mixture was then rapidly mixed for 20 seconds and the rising at 38 ° C temperature was lowered by external cooling to less than 20 ⁰ C. The mixing and cooling treatment was repeated twice, and then the upper layer was removed and dried. The solvent was evaporated off under reduced pressure and gave 24.7 parts of the product. This amount corresponds to a 94 # conversion.

When the isocyanate was analyzed it was found to contain 0.76% hydrolyzable chlorine and 27.9 % isocyanate (as -NCO).

Example 6

Polycyclohexylene polyisocyanate containing methylene bridges, prepared according to Examples 4 or 5i was made using the following components processed into clear lacquers:

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Parts by weight

Paralac 65X (one of the Änmelderin distributed alkyd resin with -OH end groups) -

Alkydol RD 18. (One of the Alkyd resin with -OH end groups sold by the applicant) -100

Paralac 4-85X (one of the Alkyd resin with -OH end groups sold by the applicant) -

Solvent mixture of) 3 parts of ethyl acetate) ^ ₄ 1 part of methyl isobutyl ketone) ^D 1 part of cellosolve acetate)

Polyisocyanate according to Example 4-31

100

- 100 12.6 '20.9

White tiles were painted with these varnishes and dried in the open air. Similar paints continued to be used made using an equivalent amount of crude diphenylmethane diisocyanate (M.D.I.) in place of the Polyisocyanate according to the invention. The films were then exposed to ultraviolet light (xenon lamp) for 120 hours; exposed and it was found that all the films from the raw M.D.I. had become severely discolored (yellow), while the films made from polycyclohexylene polyisocyanates containing methylene bridges not discolored.

Example 7

The polycyclohexylene polyisocyanates containing methylene bridges according to example 4- were processed into pigmented paints using the following components:

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Parts by weight

A Ά

Alk'ydol ED 18 (one of the

Änmelderin displaced

Alkyd resin with hydroxyl end

groups) '100 -

Paralac 4-85X (one of the

Applicant distributed

Alkyd resin with hydroxyl end

groups) - 100

Tioxide RCE

(an Eutil titanium dioxide pigment,
supplied by Tioxide International Ltd.) "51.0 34.2

Mona s tr al Past Blue "LBXS

(a phthalocyanine pigment, »

supplied by the applicant) 2.0 1.3

Solvent mixture as in

Example 6 124 57

Polyisocyanate as in

Example 4 31.0 20.9

The paints were painted on white tiles and allowed to air dry. There were also similar paints made using an equivalent amount of crude diphenylmethane diisocyanate in place of the polyisocyanate according to the invention. The cured films were exposed to ultraviolet for a total of 120 hours Exposed to light (xenon lamp) and it was found that the films were made from the crude diphenylmethane diisocyanate had changed color in that the blue coatings had taken on a greenish hue. In contrast the films with the polycyclohexylene polyisocyanate containing methylene bridges showed no discoloration.

Example 8

68.4 parts molecular weight oxypropylated glycerin of 410 was heated to 100.degree. C. under vacuum and then allowed to cool to 35.degree. 0.27 parts of stannous octoate

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and polycyclohexylene polyisocyanates containing 74-1 ^ parts of methylene bridges, prepared according to Example 4-. and 5 ₅ were added to the polyol and the solution was stirred for 5 minutes and then poured into a mold heated to 95 ° C. After the mold was heated to 95 ° C for 4-5 minutes, it was cooled and the pale yellow colored leaf was removed. This product was excellent in flexural strength and abrasion resistance, and the coloration thereof remained unchanged even when exposed to ultraviolet light (xenon lamp) for 120 hours.

Patent claims :

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Claims (9)

PATENT CLAIMS: 1 .- * - mixtures of polycyclohexylenepolyisocyanates containing methylene bridges, which consists essentially of a mixture of diisocyanates, triisocyanates and polyisocyanates higher functionality exist. 2. Mixtures according to claim L, characterized in that they contain 35 to 85 wt .- ^ diisocyanato-dicyclohexylmethane, from 5 to 35 % methylene bridge tricyclohexylcntriisocyanates together with methylene bridge polycyclohexylene polyisocyanates of higher functionality. 3. Mixtures according to claims 1 or 2, characterized in that 5 to 20 % of the rings have non-reduced and aromatic character. 4-. Process for the preparation of a mixture of polycyclohexylene polyisocyanates having methylene bridges, thereby characterized in that a mixture of polycyclohexylenepolyamines containing methylene bridges is phosgenated 5. The method according to claim 4, characterized in, that the polycyclohexylenepolyamines containing methylene bridges by ring reduction of a mixture of methylene bridges polyphenyl polyamines produced on v / ice ends, which are produced by condensation of aniline and formaldehyde obtained in molar ratios from 1.4: 1 to 6: 1. 6. The method according to claim 5, characterized in that that the ring reduction by hydrogenation at a 409843/1128 241B879 Temperature of 180 to 25O ⁰ Q and a pressure of 50 to 900 atmospheres is carried out. 7. The method according to claim 6, characterized in that the ring ^{reduction is carried out at a temperature of 190 to 210 0} C and a pressure of 150 to 250 atmospheres. '8. The process of claims 4 to 7, ₅ characterized in that a mixture of methylene bridges having Polycyclohexylenpolyisocyarfaten is reacted with a compound containing two or more isocyanate-reactive groups. 9. The method according to claim 8, characterized in that the isocyanate-reactive groups are hydroxyl groups. Wt.-JNG.H - VI-BOHi 409843/1128