Patent Application
20240368335
The present invention relates to a process for preparing at least one polyisocyanate R(—NCO)x, a polyisocyanate R(—NCO)x prepared according to said process and a chemical production unit for carrying out the process for preparing at least one polyisocyanate R(—NCO)x. The present invention further relates to a use of the polyisocyanates R(—NCO)x prepared according to said process.
Polyisocyanates are an important raw material for the production of polyurethanes. These include in particular aromatic di- and polyisocyanates such as TDI and MDI. They are essentially produced by phosgenation of the corresponding polyamines.
The amines are produced in separate plants by hydrogenating nitroaromatics. In the case of MDI, the aniline obtained is condensed in a further stage with, for example, formaldehyde to form polymethylene phenylamines (MDA).
Further, phosgenation is a well-known process for preparing isocyanates. Thereby in liquid phosgenation process the amine is mixed with a solvent and reacted with a phosgene-containing stream to form the isocyanate. After the reaction step hydrogen chloride, excess phosgene and solvent have been separated off, a crude isocyanate product is obtained, which is optionally purified again (TDI) or separated into various types of product (MDI). This is for example disclosed in U.S. Pat. No. 4,847,408 B, US 2004/0260117 A1, and EP 2 912 010 B1.
Furthermore, phosgenations are known in which an amine-containing liquid or gaseous stream and a gaseous phosgene-containing stream are mixed and subsequently reacted, this is disclosed for example in U.S. Pat. No. 8,436,204 B2, WO 2013/060836 A and WO 2013/079517 A.
The quality of the isocyanates products must meet the relevant specifications. Common quality parameters for MDI are the NCO functionality, content of easily and difficultly hydrolyzable chlorine, total chlorine content and color parameters. Such quality parameters depend on the process for preparing isocyanates. Therefore, there is always a need to provide improved process for preparing polyisocyanates which exhibits improved quality parameters, such as decreased easily hydrolysable chlorine (EHC) and high lightness value (L*).
Therefore, it was an object of the present invention to provide an improved process for preparing polyisocyanates which exhibits improved quality parameters, such as decreased easily hydrolysable chlorine (EHC) and high lightness value (L*). Surprisingly, it was found that such polyisocyanates may be obtained by the process of the present invention.
Therefore, the present invention relates to a process for preparing at least one polyisocyanate R(—NCO)x, the process comprising
As to (i), it is preferred that the at least one polyamine R(—NH2)x is selected from the group consisting of monomeric methylene diphenylene diamine (mMDA), polymethylene polyphenylene polyamine (pMDA), a mixture of monomer methylene diphenylene diamine and polymethylene polyphenylene polyamine (MDA), tolylenediamine (TDA), isomers of xylylenediamine (XDA), isomers of diaminobenzene, 2,6-xylidine, naphthylene-1,5-diamine (1,5-NDA), 1,4-diaminobutane, 1,5-diaminopentane (PDA), 1,6-diaminohexane (HDA), 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 2,2-dimethyl-1,5-diaminopentane, 2-methyl-1,5-pentanediamine (MPDA), 2,4,4 (or 2,2,4)-trimethyl-1,6-diaminohexane (TMDA), 1,3- and 1,4-diaminocyclohexane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 2,4- or 2,6-diamino-1-methylcyclohexane (H6-TDA), 1-amino-1-methyl-4(3)-aminomethylcyclohexane (AMCA), 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane (NBDA), 4,4′-diaminodicyclohexylmethane, 2,4′-diaminodicyclohexylmethane, triaminocyclohexane, tris(aminomethyl)cyclohexane, triaminomethylcyclohexane, 1,8-diamino-4-(aminomethyl)octane, undecane-1,6,11-triamine, 1,7-diamino-4-(3-aminopropyl)heptane, 1,6-diamino-3-(aminomethyl) hexane and 1,3,5-tris(aminomethyl)cyclohexane. It is more preferred that the at least one polyamine R(—NH2)x is selected from the group consisting of monomeric methylene diphenylene diamine (mMDA), polymethylene polyphenylene polyamine (pMDA), a mixture of monomeric methylene diphenylene diamine and polymethylene polyphenylene polyamine (MDA), and tolylenediamine (TDA).
It is preferred that the at least one polyamine R(—NH2)x is selected from the group consisting of monomeric methylene diphenylene diamine (mMDA), polymethylene polyphenylene polyamine (pMDA), and a mixture of monomeric methylene diphenylene diamine and polymethylene polyphenylene polyamine (MDA), more preferably selected from the group consisting of monomeric methylene diphenylene diamine (mMDA) and a mixture of monomeric methylene diphenylene diamine and polymethylene polyphenylene polyamine (MDA).
Preferably the monomeric methylene diphenylene diamine (mMDA) comprises, more preferably consists of, one or more 4,4′-diaminodiphenylmethane, 2,2′-diaminodiphenylmethane and 2,4′-diaminodiphenylmethane. It is more preferred that the at least one polyamine R(—NH2)x is 4,4′-diaminodiphenylmethane. Therefore, the present invention preferably relates to a process for preparing at least one polyisocyanate R(—NCO)x, with x=2 or more, the process comprising
Alternatively, it is preferred that the at least one polyamine R(—NH2)x is a mixture of monomeric methylene diphenylene diamine and polymethylene polyphenylene polyamine (MDA). Therefore, the present invention preferably relates to a process for preparing at least one polyisocyanate R(—NCO)x, the process comprising
Alternatively, it is preferred that the at least one polyamine R(—NH2)x is tolylenediamine (TDA).
Therefore, the present invention preferably relates to a process for preparing at least one polyisocyanate R(—NCO)x, the process comprising
In the context of the present invention, it is preferred that from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, of the mixture R1 consists of the at least one polyamine R(—NH2)x.
It is preferred that from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, of the mixture R1 consists of monomeric methylene diphenylene diamine (mMDA), more preferably 4,4′-diaminodiphenylmethane. It is alternatively preferred that from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, of the mixture R1 consists of MDA, namely a mixture of monomeric methylene diphenylene diamine and polymethylene polyphenylene polyamine. It is alternatively preferred that from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, more preferably from 99.5 to 100 weight-%, of the mixture R1 consists of tolylenediamine (TDA), more preferably a mixture of 2,4-diaminotoluene (80 weight-%) and 2,6-diaminotoluene (20 weight-%).
As to the preparation of the mixture R1 comprising at least one polyamine R(—NH2)x according to (i), it is noted that any process known in the art can be used. For example, such a process is disclosed in WO 2017/125302 A1.
As to (i), it is preferred according to the present invention that it comprises
Preferably the primary amines in (i.1) are aniline. Alternatively, different starting amines can be used depending on the polyamine the skilled person would like to obtain in (i). Processes for preparing polyamine are detailed in the art.
Preferably the aldehyde compound in (i.1) is formaldehyde.
Preferably the acid in (i.1) is one or more of hydrochloric acid, sulphuric acid and phosphoric acid, more preferably hydrochloric acid.
In the context of the present invention, it is preferred that the portion P1 has the same chemical and physical composition as R1 and the portion P2 has the same chemical and physical composition as P1.
It is however noted that for example in case the mixture R1 is prepared with different ratios of primary amines to aldehyde over the time compared to at the start of the process, the resulting polyamine in the portion P1 would be different when entering the storing device compared to the polyamine present initially.
In the context of the present invention, it is preferred that the storing device D1 according to (ii) is one or more storing tanks. Preferably the storing tanks are made of one or more of carbon steel, duplex steel and stainless steel.
Preferably storing P1 in D1 according to (ii) is performed in the dark.
Preferably storing P1 in D1 according to (ii) is performed under a gas atmosphere, the gas atmosphere being an inert gas, more preferably nitrogen. Without wanting to be bound to any theory, it is believed that this would prevent for example the coloring of the mixture R1 comprising at least one polyamine. In the context of the present invention, the expression “under a gas atmosphere” can be used interchangeably with the expression “in a gas atmosphere”.
Preferably, in D1, the temperature of the liquid phase of P1, T(P1), in ° C., is above the melting point of the at least one polyamine R(—NH2)x comprised in P1, M(P1), in ° C., more preferably T(P1)≥5° C.+M(P1), more preferably T(P1)≥20° C.+M(P1).
Preferably, M(P1) is 80° C., and, in D1, T(P1)≥85° C., more preferably T(P1)≥100° C. It is more preferred that, in D1, 120° C.≤T(P1)≤190° C., more preferably 130° C.≤T(P1)≤180° C., more preferably 135° C.≤T(P1)≤175° C., more preferably 140° C.≤T(P1)≤170° C.
Preferably, when the at least one polyamine R(—NH2)x is MDA, M(P1) is 80° C., and, in D1, T(P1)≥85° C., more preferably T(P1)≥100° C. It is more preferred, when the at least one polyamine R(—NH2)x is MDA, that, in D1, 120° C.≤T(P1)≤190° C., more preferably 130° C.≤T(P1)≤170° C., more preferably 135° C.≤T(P1)≤145° C.
Preferably, when the at least one polyamine R(—NH2)x is TDA, M(P1) is 100° C., and, in D1, T(P1)≥105° C. It is more preferred, when the at least one polyamine R(—NH2)x is TDA, that, in D1, T(P1)≥120° C., more preferably 120° C.≤T(P1)≤180° C., more preferably 125° C.≤T(P1)≤150° C., more preferably 125° C.≤T(P1)≤135° C.
Preferably the storing device D1 is ventilated with a gas atmosphere, more preferably the gas atmosphere being an inert gas, more preferably nitrogen.
As to the pressure in the storing device D1, it is preferred that it is in the range of from 0.5 to 2, bar (abs), more preferably in the range of from 0.8 to 1.3 bar (abs), more preferably in the range of from 1 bara to 1.1 bar (abs).
Preferably Δt1 is in the range of from 15 minutes to 6 d, more preferably in the range of from 45 minutes to 5d, more preferably in the range of from 1 h to 4 d.
It is more preferred that Δt1 is in the range of from 2 h to 3 d, more preferably in the range of from 5 h to 1 d, more preferably in the range of from 7 h to 20 h, more preferably in the range of from 8 h to 16 h.
Preferably removing at least a portion P2 of P1 according to (iii) comprises pumping the at least one portion P2 from the storing device D1.
As to the preparation of the mixture R2 comprising at least one polyamine R(—NH2)x according to (iii), it is noted that any process known in the art can be used. For example, such a process is disclosed in WO2013/060836 A1.
It is preferred that reacting, in Z2, the at least one polyamine R(—NH2)x comprised in P2 with phosgene according to (iii) comprises
It is preferred that admixing the solvent to the at least one polyamine R(—NH2)x comprised in P2 be performed with a static mixer.
Preferably the solvent is selected from the group consisting of monochlorobenzene, toluene, o- or p-dichlorobenzene, trichlorobenzene, chlorotoluene, chloroxylene, chloroethylbenzene, chloronaphthalene, chlorodiphenyl, xylene, decahydronaphthalene, benzene and a mixture of two or more thereof, more preferably selected from the group consisting of monochlorobenzene, toluene and o-dichlorobenzene, more preferably monochlorobenzene.
It is preferred that the reaction zone Z2 comprises a reactor, wherein the reactor is more preferably one or more of stirred vessels, plug-flow reactor and reaction columns.
It is preferred that the process further comprises
Preferably purifying the mixture R2 according to (iv) comprises removing one or more of phosgene, hydrogen chloride and a portion of the solvent, more preferably removing phosgene, hydrogen chloride and a portion of the solvent, from R2.
It is preferred that the process further comprises
It is preferred that from 80 to 100 weight-%, more preferably from 85 to 99 weight-%, more preferably from 90 to 98 weight-%, of the mixture R3 consist of monomeric methylene diphenylene diisocyanate (mMDI), more preferably 4,4′-methylene (diphenyl diisocyanate). Alternatively, it is preferred that from 80 to 100 weight-%, more preferably from 85 to 99 weight-%, more preferably from 90 to 98 weight-%, of the mixture R3 consist of MDI, namely a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate. Alternatively, it is preferred that from 80 to 100 weight-%, more preferably from 85 to 99 weight-%, more preferably from 90 to 98 weight-%, of the mixture R3 consist of tolylene diisocyanate (TDI), more preferably a mixture of 2,4-TDI (80 weight-%) and 2,6-TDI (20 weight-%).
Preferably the process of the present invention consists of (i), (ii) and (iii), more preferably of (i), (ii), (iii) and (iv), more preferably of (i), (ii), (iii), (iv) and (v).
The present invention further relates to a polyisocyanate R(—NCO)x, with x=2 or more, obtainable or obtained according to a process according to the present invention for use in a process for preparing polyurethanes.
Preferably the polyisocyanate R(—NCO)x has a NCO functionality of 2 or more, more preferably of 2 or 3, more preferably of 2.
It is preferred that x=2.
Preferably the polyisocyanate R(—NCO)x is selected from the group consisting of monomeric methylene diphenylene diisocyanate (mMDI), polymethylene polyphenylene polyisocyanate (pMDI), a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate (MDI), tolylene diisocyanate (TDI), isomers of xylylene diisocyanate (XDI), isomers of diisocyanatobenzene, xylene 2,6-isocyanate, naphthylene 1,5-diisocyanate (1,5-NDI), 1,4-diisocyanate, pentane 1,5-diisocyanate (PDI), hexane 1,6-diisocyanate (HDI), octane 1,8-diisocyanate, nonane 1,9-diisocyanate, decane, 1,10-diisocyanate, 2,2-dimethylpentane 1,5-diisocyanate, 2-methylpentane 1,5-diisocyanate (MPDI), 2,4,4 (or 2,2,4)-trimethylhexane 1,6-diisocyanate (TMDI), cyclohexane 1,3- and 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4- or 2,6-diisocyanato-1-methylcyclohexane (H6-TDI), 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane (AMCI), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, bis(isocyanatomethyl)norbornane (NBDI), 4,4′-diisocyanatodicyclohexylmethane, 2,4′-diisocyanatodicyclohexylmethane, triisocyanatocyclohexane, tris(isocyanatomethyl)cyclohexane, triisocyanatomethylcyclohexane, 1,8-diisocyanato-4-(isocyanatomethyl) octane, undecane 1,6,11-triisocyanate, 1,7-diisocyanato-4-(3-isocyanatopropyl) heptane, 1,6-diisocyanato-3-(isocyanatomethyl)hexane and 1,3,5-tris(isocyanatomethyl)cyclohexane, more preferably selected from the group consisting of monomeric methylene diphenylene diisocyanate (mMDI), polymethylene polyphenylene polyisocyanate (pMDI), a mixture of monomer methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate (MDI), and tolylene diisocyanate (TDI).
It is preferred that the polyisocyanate R(—NCO)x is selected from the group consisting of monomeric methylene diphenylene diisocyanate (mMDI), polymethylene polyphenylene polyisocyanate (pMDI) and a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate (MDI), more preferably selected from the group consisting of monomeric methylene diphenylene diisocyanate (mMDI) and a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate (MDI).
Preferably the monomeric methylene diphenylene diisocyanate (mMDI) comprises, more preferably consists of, one or more 4,4′-methylene (diphenyl diisocyanate) (4,4′-MDI), 2,2′-methylene (diphenyl diisocyanate) (2,2′-MDI) and 2,4′-methylene (diphenyl diisocyanate) (2,4′-MDI), more preferably 4,4′-methylene (diphenyl diisocyanate) (4,4′-MDI). It is more preferred that the polyisocyanate R(—NCO)x is a monomeric methylene diphenylene diisocyanate (mMDI) which comprises, more preferably consists of, one or more 4,4′-methylene (diphenyl diisocyanate) (4,4′-MDI), 2,2′-methylene (diphenyl diisocyanate) (2,2′-MDI) and 2,4′-methylene (diphenyl diisocyanate) (2,4′-MDI), more preferably 4,4′-methylene (diphenyl diisocyanate) (4,4′-MDI). It is more preferred that the polyisocyanate R(—NCO)x is 4,4′-methylene (diphenyl diisocyanate) (4,4′-MDI).
Alternatively, it is preferred that the polyisocyanate R(—NCO)x is MDI, namely a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate.
Alternatively, it is preferred that the polyisocyanate R(—NCO)x is TDI, namely a mixture of 2,4-TDI (80 weight-%) and 2,6-TDI (20 weight-%).
In the context of the present invention, it is preferred that the polyisocyanate R(—NCO)x has a NCO content in the range of from 10 to 60 weight-%, more preferably in the range of from 20 to 55 weight-%, based on the total weight of the polyisocyanate.
It is more preferred that the polyisocyanate R(—NCO)x has a NCO content in the range of from 25 to 35 weight-%, preferably in the range of from 30 to 35 weight-%, based on the total weight of the polyisocyanate.
It is preferred that the polyisocyanate R(—NCO)x is MDI, namely a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate, and that it has a NCO content in the range of from 25 to 34 weight-%, preferably in the range of from 30 to 33.6 weight-%, based on the total weight of the polyisocyanate.
It is preferred that the polyisocyanate R(—NCO)x comprises a content of easily hydrolysable chlorine (EHC) of at most 500 mg/kg, more preferably of at most 450 mg/kg, more preferably of at most 400 mg/kg, the EHC being preferably determined according to ASTM D4667-87.
It is preferred that the polyisocyanate R(—NCO)x is MDI, namely a mixture of monomeric methylene diphenylene diisocyanate and polymethylene polyphenylene polyisocyanate, and that it comprises a content of easily hydrolysable chlorine (EHC) of at most 500 mg/kg, more preferably of at most 450 mg/kg, more preferably of at most 400 mg/kg, the EHC being preferably determined according to ASTM D4667-87.
It is preferred that the polyisocyanate R(—NCO)x has a brightness value L* of at least 40, more preferably in the range of from 40 to 100, more preferably in the range of from 45 to 99, more preferably in the range of 55 to 98, more preferably in the range of from 75 to 95, the brightness value L* being preferably determined according to ASTM D7133-16.
It is preferred that the polyisocyanate R(—NCO)x is 4,4′-MDI and that it has a brightness value L* of at least 40, more preferably in the range of from 40 to 100, more preferably in the range of from 45 to 99, more preferably in the range of from 45 to 80, the brightness value L* being preferably determined according to ASTM D7133-16.
It is preferred that the polyisocyanate R(—NCO)x is MDI (the mixture as defined in the foregoing) and that it has a brightness value L* of at least 40, more preferably in the range of from 40 to 100, more preferably in the range of from 45 to 99, more preferably in the range of 55 to 98, more preferably in the range of from 75 to 95, the brightness value L* being preferably determined according to ASTM D7133-16.
It is preferred that, when the polyisocyanate is TDI (the mixture as defined in the foregoing), said polyisocyanate has a NCO content in the range of from 40 to 50 weight-%, more preferably in the range of from 45 to 50 weight-%, based on the total weight of the polyisocyanate. It is preferred that the polyisocyanate is TDI, namely a mixture of 2,4-TDI (80 weight-%) and 2,6-TDI (20 weight-%).
It is preferred that the polyisocyanate R(—NCO)x is TDI (the mixture as defined in the foregoing) and that it has a brightness value L* of at least 40, more preferably in the range of from 40 to 100, more preferably in the range of from 45 to 99, more preferably in the range of 55 to 98, more preferably in the range of from 75 to 95, the brightness value L* being preferably determined according to ASTM D7133-16.
The present invention further relates to a use of at least one polyisocyanate R(—NCO)x, with x=2 or more, according to the present invention, for preparing polyurethanes.
The present invention further relates to a chemical production unit for carrying out the process for preparing at least one polyisocyanate R(—NCO)x according to the present invention, comprising
The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as “The process of any one of embodiments 1 to 5”, every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to “The process of any one of embodiments 1, 2, 3, 4 and 5”. Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.
It is explicitly noted that the above set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.
In the context of the present invention, a term “X is one or more of A, B and C”, wherein X is a given feature and each of A, B and C stands for specific realization of said feature, is to be understood as disclosing that X is either A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. In this regard, it is noted that the skilled person is capable of transfer to above abstract term to a concrete example, e.g. where X is a chemical element and A, B and C are concrete elements such as Li, Na, and K, or X is a temperature and A, B and C are concrete temperatures such as 10° C., 20° C., and 30° C. In this regard, it is further noted that the skilled person is capable of extending the above term to less specific realizations of said feature, e.g. “X is one or more of A and B” disclosing that X is either A, or B, or A and B, or to more specific realizations of said feature, e.g. “X is one or more of A, B, C and D”, disclosing that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D.
The present invention is further illustrated by the following example 1 and
4,4′-Methylenedianiline (4,4′-MDA) was stored in the dark at two different temperatures, namely 140 and 170° C., for a total of 12 weeks in the absence of air. After various storage stages (0, 1, 4 and 12 weeks), part of the stored MDA sample was removed and converted to the corresponding isocyanate.
To do so, after each various storage stage, 100 g of MDA was dissolved in 1200 g of mono chlorobenzene (MCB) and metered into a stirred 2.7 L reactor over 1 hour at about 50° C., wherein a solution of 200 g of phosgene and 1200 g of MCB was placed under reflux. During the dosing, a suspension forms which clears up after heating up to 120° C.
After partial cooling, HCl, phosgene and parts of the solvent are removed from the mixture comprising methylene diphenyl diisocyanate (MDI) by evacuation.
After the aforementioned removal, the obtained mixture comprising MDI was drained off and filled into a rotary evaporator, where the solvent was separated off initially at 50 mbar and at 100° C. and later at 20 mbar and at 180° C. Further, a de-chlorination step is performed according to method well-known in the art, obtaining a MDI stream.
The NCO number, easily hydrolysable chlorine (EHC) and brightness values (L*) are determined from the resulting MDI samples (a-h). The EHC was determined according to ASTM D4667-87 and the brightness value L* being determined according to ASTM D7133-16. The values show a significant deterioration in the quality parameters, increase of EHC and decrease of L*, after just 1 week of exposure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21175682.0 | May 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/064007 | 5/24/2022 | WO |
