CA2139535A1 - Modified (cyclo)aliphatic polyisocyanate mixtures, preparation thereof and use thereof - Google Patents
Modified (cyclo)aliphatic polyisocyanate mixtures, preparation thereof and use thereofInfo
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- CA2139535A1 CA2139535A1 CA002139535A CA2139535A CA2139535A1 CA 2139535 A1 CA2139535 A1 CA 2139535A1 CA 002139535 A CA002139535 A CA 002139535A CA 2139535 A CA2139535 A CA 2139535A CA 2139535 A1 CA2139535 A1 CA 2139535A1
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- isocyanate
- diisocyanates
- isocyanurate
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
- C08G18/78—Nitrogen
- C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
- C08G18/791—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups
- C08G18/792—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing isocyanurate groups formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
- C07C271/62—Compounds containing any of the groups, X being a hetero atom, Y being any atom, e.g. N-acylcarbamates
- C07C271/66—Y being a hetero atom
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C275/00—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C275/46—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups containing any of the groups, X being a hetero atom, Y being any atom, e.g. acylureas
- C07C275/58—Y being a hetero atom
- C07C275/60—Y being an oxygen atom, e.g. allophanic acids
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C275/00—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C275/46—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups containing any of the groups, X being a hetero atom, Y being any atom, e.g. acylureas
- C07C275/58—Y being a hetero atom
- C07C275/62—Y being a nitrogen atom, e.g. biuret
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D229/00—Heterocyclic compounds containing rings of less than five members having two nitrogen atoms as the only ring hetero atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
- C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
- C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
- C07D251/30—Only oxygen atoms
- C07D251/34—Cyanuric or isocyanuric esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
- C08G18/78—Nitrogen
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
- C08G18/78—Nitrogen
- C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
- C08G18/798—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing urethdione groups
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
- C09J175/04—Polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/10—Materials in mouldable or extrudable form for sealing or packing joints or covers
- C09K3/1006—Materials in mouldable or extrudable form for sealing or packing joints or covers characterised by the chemical nature of one of its constituents
- C09K3/1021—Polyurethanes or derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2101/00—Manufacture of cellular products
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2190/00—Compositions for sealing or packing joints
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Polyurethanes Or Polyureas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
the polyisocyanate mixtures modified by urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and having an isocyanate content of from 1 to 34% by weight whith are obtainable from diisocyanates having isocyanate groups of differing reactivity selected from the group consisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate and/or 1-(isocya-natomethyl)-1-(3-isocyanatopropyl)cyclohexane.
Description
2139~3~
.
Modified (cyclo)aliphatic polyisocyanate mixtures, preparation thereof and use thereof 5 The present invention relates to polyisocyanate compositions modified by urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and having an isocyanate content of from 1 to 34~ by weight, based on the total weight, which are prepared from diisocyanates having isocyanate groups of 10 differing reactivity selected from the group consisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopro-pyl)cyclohexyl-l-isocyanate and/or l-(isocyanatomethyl)-1-(3-iso-cyanatopropyl)cyclohexane, a process for the preparation thereof and use thereof.
It is known that polyisocyanate polyaddition products can be pre-pared by reaction of organic polyisocyanates with compounds con-taining hydrogen atoms which react with NCo groups, such as the hydrogen atoms of hydroxyl, amino, mercapto or carboxyl groups, 20 in the presence or absence of catalysts, solvents and other addi-tives. It is frequently advantageous or even necessary to modify the organic polyisocyanates prior to their use for the formation of polyisocyanate polyaddition products for specific applica-tions. Reasons for this can be, for example, the lowering of the 25 vapor pressure, a change in the viscosity and thus their processibility, the functionality and the reactivity and also, in particular, the achievement of specific mechanical properties in the final products. The modification is carried out by a partial chemical alteration of the isocyanate groups, so that relatively 30 high-molecular-weight polyisocyanate compositions still having free, reactive isocyanate groups result. As industrially most im-portant modification reactions, mention may be made of, for ex-ample, the dimerization and trimerization to give uretdione and isocyanurate groups and the formation of carbodiimide, biuret, 35 urea, urethane and/or allophanate groups. By means of suitable catalysts and reaction conditions, it is generally possible to achieve a selective modification.
For the preparation of such polyisocyanate mixtures containing 40 urethane, allophanate, urea, biuret, carbodiimide, uretdione and~
or isocyanurate groups, it is possible to react, for example, al-iphatic or cycloaliphatic diisocyanates or mixtures of aliphatic and cycloaliphatic diisocyanates in the presence of a suitable catalyst in the absence of solvent or with addition of a solvent 45 and, if desired, an additive, advantageously at elevated tempera-tures, for example at from 60 to 140 C, until the desired conver-sion is achieved. Subsequently, the catalysts can be deactivated 213953~
thermally and/or by addition of a catalyst poison and, if desired, the excess monomeric (cyclo)aliphatic diisocyanates and any solvents added can be separated off. The separation is pre-ferably carried out by distillation under reduced pressure by 5 means of a thin-film evaporator. Modified polyisocyanate mixtures - prepared by such processes can be reacted with relatively high-molecular-weight and/or low-molecular-weight polyhydroxyl com-pounds, eg. polyether polyols, polyester polyols or polyhydroxya-crylates, to give NCO-cont~ining prepolymers. Furthermore, the 10 isocyanate groups of the modified polyisocyanate compositions or NCO prepolymers can be capped or blocked. For this purpose, the NCO groups are reacted with compounds which can relatively easi-ly, advantageously at elevated temperature, be cleaved off again to give NCo groups. The reactive isocyanate group thus liberated 15 can then react further in a known manner, eg. with hydroxyl or amino groups. Suitable capping agents are, for example, phenols, caprolactam, B-dicarbonyl compounds such as acetoacetic esters, dialkylmalonates, oximes, triazoles and certain alcohols. Modi-fied and/or blocked polyisocyanate mixtures are used, in particu-20 lar, in high-performance single-component and two-component sys-tems for finishes and coatings.
Use of organic polyisocyanates containing isocyanate groups of differing reactivity, eg. (cyclo)aliphatic diisocyanates such as 25 2-ethylbutane-1,4-diisocyanate, 2-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexane-1,6-diisocyanate (TMHDI) or isocyanatome-thyl-3,5,5-trimethylcyclohexylisocyanate (IPDI), enables, by reaction of the more reactive isocyanate group, the pre?aration of modified polyisocyanate mixtures having reduced reactivity, 30 which mixtures have relatively long processing times.
There have therefore been many attempts, by means of appropriate modification of (cyclo)aliphatic diisocyanates having isocyanate groups of differing reactivity, to improve their shelf life, pro-35 cessibility and the mechanical properties of polyisocyanate poly-addition products prepared therefrom.
According to EP-A-O 045 995 (US-A-4 476 054), isocyanurate-free uretdiones can be prepared from IPDI in the presence of a cata-40 lyst of the formula XmP(NR2)3_m, where m is 0, 1 or 2, X is Cl, ORor R and R are identical or different alkyl, benzyl, phenylethyl, cyclohexyl and cyclopentyl radicals. Such IPDIs containing uret-dione groups can be reacted with diols and, if desired, with monoalcohols or monoamines in accordance with EP-A-O 045-996 - -~~-45 (US-A-4 483 798) to give polyaddition products containing uret-dione groups, which products can, according to EP-A-O 045 997 (US-A-4 430 474), be used for the production of stoving enamels.
-`` 213953~
, Isocyanatouretdiones and a process for the preparation thereof using 2-methyl-1,5-diisocyanatopentane and 2-ethyl-1,4-diisocya-natobutane as suitable starting materials are also described in EP-A-O 099 976 (US-A-4 668 780). The polyisocyanates containing 5 uretdione groups are intermediates for producing plastics, finishes and foam materials.
Isocyanatoisocyanurates and processes for the preparation thereof or the preparation of ~torage-stable solutions thereof are 10 described in EP-B-0 082 987 (US-A-4 469 867) and DE-B-2 325 826 (US-A-3 919 218). According to EP-A-0 082 987, isocyanatoisocya-nurates are prepared by partial trimerization of 2-methyl-1,5-diisocyanatopentane or mixtures of 2-meth-yl-1,5-diisocyanatopentane and 2-ethyl-1,4-diisocyanatobutane.
15 According to DE-B-23 25 826, IPDI or 2,2,4- or 2,4,4-TMHDI are used as (cyclo)aliphatic diisocyanates.
Polyisocyanates cont~i n; ng biuret ylG~pS derived from 2-meth-yl-1,5-diisocyanatopentane or 2-ethyl-1,4-diisocyanatobutane are 20 described in EP-A-0 082 973.
Disadvantages of the modified polyisocyanates described are their nonuniformity in respect of their chemical structure and the reactivity of the free isocyanate groups. This nonuniformity is 25 caused by the small reactivity differences between the two iso-cyanate groups of the (cyclo)aliphatic diisocyanates specified as starting materials. A further mechanical property, undesirable for certain applications, results from the rigidity of the IPDI
molecule caused by the structure.
It is an object of the present invention to prepare modified polyisocyanate mixtures having, in comparison with known prod-ucts, more uniform molecular composition, reduced reactivity and increased processing time.
We have found that this object is achieved by modification of (cyclo)aliphatic diisocyanates having differing reactivity of the isocyanate groups, caused by their specific chemical structure.
40 The invention accordingly provides a polyisocyanate mixture con-t~ining urethane, allophanate, urea, biuret, carbodiimide, uret-dione and/or isocyanurate groups and having an isocyanate content of from 1 to 34% by weight, which is prepared by known processes from (cyclo)aliphatic diisocyanates selected from the group con-g5 sisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocya-natopropyl)cyclohexyl-1-isocyanate, l-(isocyanatomethyl)-213953~
..
1-(3-isocyanatopropyl)cyclohexane and mixtures of at least two of the specified (cyclo)aliphatic diisocyanates.
It has surprisingly been found that the reactivity differences 5 between the isocyanate groups of the (cyclo)aliphatic diisocyan-- ates which can be used according to the invention are, because of the specific substituents and their influence on the immediate steric environment, substantially more pronounced than in the known, ab~v. -ntioned (cyclo)aliphatic diisocyanates.
For example, 2-(3-isocyanatopropyl~cyclohexylisocyanate has a sterically unhindered primary isocyanate group on the propylene radical and a secondary isocyanate group on the cyclohexane ring, while in IPDI the primary isocyanate group is bonded to the 15 cyclohexane ring with only a methylene bridge (neo-group) in between.
Owing to its flexible structure, 2-butyl-2-ethylpentane-1,5-di-isocyanate has advantageous processing properties and gives poly-20 isocyanate polyaddition products having excellent mechanicalproperties. The primary isocyanate group on the C5 atom is sepa-rated from the lateral 2-ethyl and 2-butyl radicals by a propy-lene bridge and i~ therefore more reactive than the isocyanate group on the C1 atom which is sterically hindered by a neo-group 25 and is thereby deactivated. ;
Since in the reaction for modifying the (cyclo)aliphatic diisocy-anates which can be used according to the invention the more reactive primary isocyanate group reacts preferentially, the 30 polyisocyanate mixtures modified according to the invention have a reduced reactivity and, as a result, a longer processing time than polyisocyanate mixtures based on HDI, TMHDI or IPDI and mod-ified with similar groups.
35 As has already been indicated, l-(isocyanatomethyl)-1-(3-isocya-natopropyl)cyclohexane is suitable for the preparation of the polyisocyanate mixtures modified according to the invention. How-ever, the (cyclo)aliphatic diisocyanates preferably used are 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate (abbreviated to 40 IPCI) and, in particular, 2-butyl-2-ethylpentane-1,5-diisocyanate (abbreviated to HEPDI). The (cyclo)aliphatic diisocyanates which can be used according to the invention can be prepared by any processes, eg. by phosgenization of the corresponding (cyclo)ali-phatic diamines to give the corresponding dicarbamic acid 45 chloride~ and their thermal cleavage into the (cyclo)aliphatic diisocyanates and hydrogen chloride. However, preference is given to using (cyclo)aliphatic diisocyanates, in particular IPCI and 213~53S
BEPDI, which are obtainable by phosgene-free processes, in par-ticular by thermal cleavage of (cyclo)aliphatic dicarbamic esters into the (cyclo)aliphatic diisocyanates and alcohols. This ther-mal cleavage can be carried out, for example, at temperatures of 5 from lS0 to 300 C, preferably from 180 to 250 C and pressures of - from 0.001 to 2 bar, preferably from 1 to 200 mbar, in the ab-sence or preferably the presence of catalysts in suitable cleavage reactors, such as thin-film or preferably heater-plug evaporators. The (cyclo)aliphatic diisocyanates and alcohols 10 formed in the cleavage can be separated, for example, by frac-tional condensation or preferably by rectification and the (cyclo)aliphatic diisocyanates can be additionally purified, for example, by distillation.
15 The preparation of the polyisocyanate mixtures of the invention contAining urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and baQed on l-(isocyanato-methyl)-l-(3-isocyanatopropyl)cyclohexane, preferably IPCI and in particular ~EPDI is carried out by methods known per se by means 20 of catalyst-free or preferably catalytic oligomerization and/or polycondensation of the (cyclo)aliphatic diisocyanates which can be used according to the invention and~or polyaddition of these diisocyanates and/or the polyisocyanate mixtures modified accord-ing to the invention to compounds having at least one reactive 25 hydrogen atom, preferably water, monofunctional and/or polyfunc-tional alcohols and/or monofunctional and/or polyfunctional amines.
After reaching the desired content of carbodiimide, uretdione 30 and/or isocyanurate groups in the reaction mixture or the desired degree of reaction, which can, for example, be measured by deter-mining the isocyanate content of the reaction mixture, the reac-tion can be stopped by deactivating the catalyst, for example by addition of a catalyst poison or by thermal decomposition of the 35 catalyst. If monomer-free, modified polyisocyanate mixtures are required for particular fields of application, such as single-component or two-component polyurethane finishes, the unreacted monomeric diisocyanates can be removed in an appropriate manner known per se, eg. by distillation, for example by means of a 40 thin-film evaporator.
To prepare polyisocyanate mixtures contA;ning urethane and allo-phanate groups, the (cyclo)aliphatic diisocyanates which are suitable according to the invention can be reacted with alcohols, 45 preferably alkanediols in the required amounts, advantageously in amounts of, for example, from 0.005 to 0.4, preferably from O.OS
to 0.15, equivalents of hydroxyl group per equivalent of .`` 213g53~ -.
isocyanate group. Polyi50cyanate mixtures cont~;ning urea and/or biuret groups can be obtained by reaction of the (cyclo)aliphatic diisocyanates, which can be used according to the invention, with water, compounds from which water can be cleaved, such as tertia-5 ry butanol or salts cont~;n;ng water of crystallization, and pri-mary and secondary amines, preferably aliphatic and/or aromatic diamines. ~hen using a tertiary monoalkanol as the compound from which water can be cleaved, the molar ratio of diisocyanates to alcohol is usually at least 2.5:1, preferably at least 8:1.
Similar processes for preparing the polyisocyanate mixtures modi-fied according to the invention are de~cribed in literature pub-lications such as the ~unststoff-Handbuch, Volume 7, Polyurethane, Carl Hanser Verlag, 1st and 2nd Edition (1966 and 15 1983 respectively), and, in particular, patents.
For example, preparation processes are described for polyisocya-nate mixtures cont~; n; ng urethane groups in DE-B-1 618 380 (US-A-3 644 457), DE-A-25 13 793 (GB-A-14 50 660) or EP-A-10 850 20 (US-A-4 261 852), for polyisocyanate mixtures cont~;n;ng allopha-nate and isocyanurate groups in EP-A-0 566 037, for polyisocya-nate mixtures contA~n;ng urea and/or biuret groups in DE-B-1 101 394 (GB 876 503), DE-B-1 070 374, GB-A-889 050, DE-B-l 227 003 (US-A-3 284 479), DE-A-l 174 759, (US-A-3 392 183) 25 and DE-A-l 543 178 (GB-A-1 044 932), for polyisocyanate mixtures containing carbodiimide groups in DE-A-1 130 594 (US-A-2 941 966), GB-A-1 083 410, US-~-2 941 983 and DE-B-22 48 751 (US-A-4 076 945), for pclyisocyanate mixtures con-taining uretdione groups in DE-A-1 643 170 (US 3 489 744) and 30 DE-A-1 081 895 (GB-A-821 158) and for, in particular, polyisocya-nate mixtures containing isocyanurate groups in DE-A-26 16 415, US-A-3 645 979, US-3 248 372 and GB-A-837 120.
The (cyclo)aliphatic diisocyanates l-(isocyanatomethyl)-1-(3-iso-35 cyanatopropyl)cyclohexane, preferably IPCI and, in particular, BEPDI which can be used according to the invention are used to prepare, in particular, polyisocyanate mixtures modified by iso-cyanurate groups, since these are very useful for preparing high-performance single-component or two-component polyurethane (PU) 40 adhesive~ or, in particular, finishes.
To prepare the polyisocyanate mixtures of the invention contain-ing isocyanurate groups, the (cyclo)aliphatic diisocyanates which can be used according to the invention are partially cyclized in 45 a conventional manner, advantageously under an atmosphere of gases inert under the reaction conditions, such a~ nitrogen, in the presence of at least one trimerization catalyst at `` 213~5~5 _ 7 temperatures of advantageously from 30 to 140 C, preferably from 70 to 120 C. After reaching the desired isocyanurate content or NCO content, which is advantageously in a NCO range ~rom 1 to 34%
by weight, preferably from 10 to 34~ by weight, based on the 5 weight of the reaction mixture containing isocyanurate groups, and, depending on the reaction temperature selected within the specified temperature range, is usually obtained in a period of from 0.1 to 12 hours, preferably from 2 to 5 hours, the trimer-ization catalyst is deactivated by addition of a deactivator and lO the isocyanurate formation is thus stopped. The polyisocyanate mixture obtained cont~ining isocyanurate groups can, for example, be additionally modified by continuous or stepwise addition of compounds having reactive hydrogen atoms, preferably amino or, in particular, hydroxyl compounds, or the monomeric organic diisocy-15 anates can be removed, if desired, prior to or after the addi-tional modification, advantageously by means of a thin-film evaporator under reduced pressure.
To partially cyclize the (cyclo)aliphatic diisocyanates which can 20 be used according to the invention, the usual trimerization cata-lysts, such as tertiary amines, phosphines, alkoxides, metal ox-ides, hydroxides, carboxylates and organometallic c~ ~oul-dg can be used. Other trimerization catalysts which have proven very useful are tris(N,N-dialkylaminoalkyl)-S-hexahydrotriazines, such 25 as tris(N,N-dimethylaminopropyl)-S-hexahydrotriazine, and organic salts of weak acids with tetraalkylammonium groups or trialkylhy-droxyalkylammonium groups, with preference being given to for example, N,N,N-trimethyl-N-2-hydroxypropylammonium p-tert-butyl-benzoate and N,N,N-trimethyl-N-2-hydroxypropylammonium 2-ethyl-30 hexanoate because they are simple to prepare and to purify. Ithas surprisingly been found that the type of catalyst can also effect an additional selective trimerization; in comparison to tetraalkylammonium carboxylates, the use of silylamines, prefer-ably of bis(trimethylsilyl)amine, preferentially activates the 35 more reactive primary isocyanate group. Since this selective trimerization makes the molecular structure and reactivity more uniform, particular preference is given to using silylamines as catalysts for preparing the polyisocyanate mixtures containing isocyanurate groups. The trimerization catalysts, which can also 40 effect the formation of uretdione groups and oligomeric isocyanurate groups as byproducts, are usually used in an amount of from 0.001 to 0.5% by weight, preferably from 0.01 to 0.05% by weight, based on the weight of the organic diisocyanates.
45 As has already been indicated, the trimerization catalysts are usually deactivated after formation of the desired amount of isocyanurate groups. Suitable deactivators in case of the ` 213953S
.
first-mentioned ionic catalysts are, for example, inorganic or organic acids, the corresponding acid halides and alkylating agents. Examples which may be mentioned are phosphoric acid, mo-nochloroacetic acid, dodecylbenzenesulfonic acid, benzoyl chlo-5 ride, dimethyl sulfate and preferably dialkyl phosphates, in par-ticular dibutyl phosphate. To deactivate the silylamine cata-lysts, use is preferably made of monofunctional and difunctional alcohols such as n-butanol, n-hexanol, 1,2-propanediol and~or 1,4-butanediol. The deactivators can be used in amounts of from 1 10 to 300 mol%, preferably from 50 to 150 mol%, based on the number of moles of trimerization catalyst.
Although the polyisocyanates containing isocyanurate and, if de-sired, uretdione groups would also be able to be prepared using 15 inert solvents or diluents, these are preferably not used in the process of the invention for ecological and economic reasons.
The polyisocyanate mixtures of the invention cont~; n; ng isocya-nurate groups advantageously contain at least 50% by weight, pre-20 ferably at least 60% by weight and in particular at least 70% byweight, based on the isocyanurate-polyisocyanates, of polyiso-cyanates of the formula i~
\
213953~
R ~ R
0 - C ~ ~ =
N
R
10 where R is a radical selected from the group consisting of y 15 -CH2-CH2-CH2 CH2-NCO , preferably 20 -CH2-CH2-CH2 ~ and in particular C2Hs I
25 -CH2-CH2-CH2-C-CH2-NC0 t C4Hg The polyisocyanate mixtures of the invention containing urethane, 30 allophanate, urea, biuret, carbodiimide, uretdione and/or iso-cyanurate groups have an isocyanate content in the range from 1 to 34% by weight, based on the total weight. According to pre-ferred embodiments, the polyisocyanate mixtures containing ure-thane groups preferably have an isocyanate content of from 1 to 35 30% by weight, in particular from 1.5 to 26% by weight, the poly-isocyanate mixtures cont~;n;ng allophanate groups preferably have an isocyanate content of from 1 to 30% by weight, in particular from 1.5 to 26% by weight, the polyisocyanate mixtures cont~;n;ng urea groups preferably have an isocyanate content of from 1 to 40 30% by weight, in particular from 3 to 26% by weight, the poly-isocyanate mixtures containing biuret groups preferably have an isocyanate content of from 5 to 34% by weight, in particular from 5 to 25% by weight, the polyisocyanate mixtures cont~;n;ng carbo-- diimide groups preferably have an isocyanate-content of from 2 to-45 33% by weight, in particular from 5 to 30% by weight, the poly-- isocyanate mixtures cont~i ni ng uretdione groups preferably have an isocyanate content of from 5 to 33% by weight, in particular ` ~1395~5 from lO to 30% by weight, and the polyisocyanate mixtures con-t~i ni ng isocyanurate groups preferably have an isocyanate content of from 10 to 34~ by weight, in particular from 10 to 30% by weight, with the percentages by weight being in each case based 5 on the total weight of the polyisocyanate mixtures. If the poly-isocyanate mixtures modified according to the invention were mo-dified with more than one of the groups relevant to the inven-tion, eg. a uretdione and an isocyanurate group, a carbodiimide and an isocyanurate group, a urethane and an isocyanurate group, 10 a urethane and an allophanate group, a urethane and at least one carbodiimide group or a urea and a biuret group, the isocyanate contents are likewise within the isocyanate percentage region specified above for one group.
15 The polyisocyanate mixtures modified according to the invention can be used in the form obtained or be diluted prior to proces-sing with a solvent inert towards isocyanate groups, eg. for re-ducing the viscosity and improving the flowability. The type of solvent which may, if desired, be advantageously used is usually 20 also dependent on the application of the polyisocyanate mixtures modified according to the invention. Suitable solvents are, for example, those solvents and diluents which are inert towards iso-cyanate groups and are usual in the surface coatings and adhe-sives industry.
f~'`
The polyisocyanate mixtures of the invention cont~ining urethane, allophanate, biuret, carbodiimide, uretdione and/or isocyanurate groups are useful, for example, for preparing polyurethane finish systems, such as single-component or t~v co...ponent finishes, 30 polyurethane coatings, dispersions, adhesives such as single-com-ponent or two c~.,.ponent adhesives, polyurethane sealants, cellu-lar or compact polyurethane elastomers, casting elastomers and foam materials such as flexible, semi-rigid or rigid block or shaped foam materials and also the corresponding integral foam 35 materials.
\
Examples The viscosity specified in the examples was measured in accord-40 ance with DIN 53019 using a rotation viscometer at 23 C.
In the examples and comparative examples, use was made of the following diisocyanates as they were abbreviated in the descrip-tion of the invention:
213g~35 HDI: 1,6-hexamethylenedii50cyanate (1,6-diisocyanatohexane), TMHDI: 2,2,4-trimethylhexamethylene-1,6-diisocyanate, IPDI: 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophoronediisocyanate), S IPCI: 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate and ~EPDI: 2-butyl-2-ethylpentane-1,5-diisocyanate.
Example 1 10 Preparation of a polyisocyanate mixture containing biuret groups and based on IPCI.
500 parts by weight of IPCI having an NC0 content of 40.3% by weight and 15 parts by weight of tert-butanol were mixed with 15 stirring in a multi-neck flask fitted with stirrer, reflux con-denser and septum, and the reaction mixture was heated to 160 C.
0.5 parts by weight of para-toluenesulfonic acid, dissolved in 2.8 parts by weight of tert-butanol, were added dropwise to the 20 reaction mixture over a period of 10 minutes. Vigorous evolution of carbon dioxide and isobutene commenced, this stopping after about 30 minutes. To complete the reaction, the reaction mixture was stirred for a further 60 minutes at 160 C, then allowed to cool to room temperature and degasqed for 30 minutes at room tem-25 perature under reduced pressure (about 20 mbar). The polyisocya-nate mixture obtained, which had an isocyanate content of 32.9%
by weight, was subjected to distillation using a thin-film evap-orator to remove the unreacted monomer IPCI.
30 This gave a viscous, yellow polyisocyanate mixture containing biuret and uretdione groups and having an isocyanate content of 19.7% by weight and a viscosity at 23 C of greater than 10 000 mPas.
35 Example 2 Preparation of a polyisocyanate mixture cont~i n; ng biuret groups and based on BEPDI.
40 The procedure of Example 1 was repeated, but the starting materi-als used were 700 parts by weight of ~EPDI having an isocyanate content of 34.8~ by weight, 24 part~ by weight of tert-butanol and 0.7 parts by weight of para-toluenesulfonic acid dissolved in 2.0 parts by weight of tert-butanol.- ~ ~
`` 21395~
The polyisocyanate mixture obtained, which had an isocyanate con-tent of 20.3% by weight, was subjected to distillation using a thin-film evaporator to remove the unreacted monomer BEPDI.
5 This gave a viscous, yellow polyisocyanate mixture containing biuret groups and having an isocyanate content of 16.1% by weight and a viscosity at 23 C of greater than 10 000 mPas.
Example 3 Preparation of a polyisocyanate mixture cont~; n; ng urethane and allophanate groups and based on BEPDI.
500 parts by weight of ~EPDI having an isocyanate content of 15 34.8% by weight, 31.1 parts by weight of n-butanol and 0.27 parts by weight of copper(II) acetylacetonate were mixed under a nitro-gen atmosphere in a multi-neck flask fitted with stirrer, gas in-let and outlet, reflux condenser and septum, the reaction mixture was heated to 80 C and reacted at this temperature for 6 hours. To 20 the reaction mixture obtained, which had an isocyanate content Gf 23.6~ by weight, there was added 0.44 part by weight of dibutyl phosphate and the unreacted BEPDI was subsequently distilled off under reduced pressure (about 3 mbar) by means of a thin-film evaporator.
This gave an oily polyisocyanate mixture cont~;ning urethane and allophanate groups and having an isocyanate content of 15.2~ by weight and a viscosity at 23 C of 6140 mPas.
30 Example 4 Preparation of a polyisocyanate mixture containing allophanate and isocyanurate groups.
35 A mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 13.8 parts by weight of 2-ethyl-hexanol was heated to 100 C under a nitrogen atmosphere in a multi-neck flask equipped as described in Example 3, and reacted at this temperature for one hour. The reaction mixture, which was 40 allowed to cool to 80 C, then had an isocyanate content of 32.9 by weight.
At this temperature, 0.2~ by weight, based on the weight of the ~EPDI used, of trimethyl-2-hydroxypropylammonium 2-ethylhexanoate 45 was added to the reaction mixture as trimerization catalyst, the mixture was stirred at 80 C for 4 hours and the trimerization cat-alyst was deactivated by addition of 0.2~ by weight of dibutyl 213~535 _ 13 phosphate, based on the weight of the BEPDI used. The reaction mixture obtained, which had an isocyanate content of 27% by weight, was subjected to distillation using a thin-film evapora-tor to remove the monomeric BEPDI.
This gave a clear, yellowish polyisocyanate mixture containing allophanate and isocyanurate groups and having an isocyanate con-tent of 14.3~ by weight and a viscosity at 23 C of greater than 10 000 mPas.
Example 5 Preparation of a polyisocyanate mixture cont~ining isocyanurate and urethane groups To 500 parts by weight of BEPDI in a multi-neck flask equipped as described in Example 3, there was added 0.2~ by weight, based on the BEPDI, of trimethyl-2-hydro~ypropylammonium 2-ethylhexanoate, the reaction mixture was heated to 80 C under a nitrogen atmos-~0 phere and the BEPDI was cyclized at this temperature for 4 hours.The trimerization catalyst was then deactivated by addition of 0.2~ by weight of dibutyl phosphate, based on the weight of BEPDI, and the reaction mixture, which had an isocyanate content of 29.4~ by weight, was reacted with 13.8 parts by weight of 25 2-ethylhexanol. After a further reaction time of 2 hours at 80 C, ~F-the reaction mixture had an isocyanate content of 27.2~ by weight. After distilling off the unreacted monomeric BEPDI by mear.s of thin-film distillation under reduced pressure, there was obtained a clear, yellowish polyisocyanate mixture containing 30 isocyanurate and urethene groups and having an isocyanate content of 13.5% by weight and a viscosity at 23 C of greater than 10 000 mPas.
EXample 6 Preparation of a polyisocyanate mixture cont~in;ng isocyanurate and uretdione groups.
In a multi-neck flask fitted with stirrer, reflux condenser and 40 gas inlet and outlet, a reaction mixture of 500 parts by weight of IPCI having an isocyanate content of 40.3~ by weight and 0.1 by weight, based on the weight of IPCI, of trimethyl-2-hydroxy-propylammonium 2-ethylhexanoate was heated to 80 C under a nitro-gen atmosphere and was cyclized for 3 hours at~-this temperature 45 while stirring. The trimerization catalyst was deactivated by addition of 0.1~ by weight of dibutyl phosphate, based on the weight of IPCI. The reaction mixture, which had an isocyanate 2139~35 -. .` .
content of 33% by weightl was subjected to thin-film distillation under reduced pressure to remove the unreacted IPCI.
This gave a clear, yellowish polyisocyanate mixture containing 5 iQocyanurate and uretdione groups and having an iQocyanate con-tent of 19.3% by weight and a viscosity at 23 C of greater than 10 000 mPas.
The polyisocyanate mixture cont~;ning isocyanurate and uretdione 10 groups was, to make further processing easier, diluted with n-butyl acetate to give a 90% by weight strength solution which had an isocyanate content of 17.3% by weight and a viscosity at 25 C of 480 mPas.
15 Example 7 Preparation of a polyisocyanate mixture contA;n;ng isocyanurate and uretdione groups 20 In a multi-neck flask equipped as described in Example 6, a reac-tion mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 0.2% by weight, based on the weight of BEPDI, of trimethyl-2-hydroxypropylammonium 2-ethylhex-anoate was heated to 80 C under a nitrogen atmosphere and cyclized 25 for 4 hours at this temperature while stirring. The trimerization catalyst was deactivated by addition of 0.2% by weight of dibutyl phosphate, based on the weight of BEPDI. The unreacted BEPDI was distilled out of the reaction mixture by means of thin-film dis-tillation under reduced pressure.
This gave a clear, yellowish, amorphous polyisocyanate mixture cont~;n;ng isocyanurate and uretdione groups and having an isocy-anate content of 15.5% by weight, the GPC chromatogram of which is shown in Figure 1.
\ The polyisocyanate mixture containing isocyanurate and uretdione groups was, for easier further processing, diluted with n-butyl acetate to give a 90% by weight strength solution which had an isocyanate content of 14.3% by weight and a viscosity at 25 C of 40 440 mPas.
`` 213~3~
, .
Example 8 Preparation of a polyisocyanate mixture cont~in;ng isocyanurate 5 and uretdione groups.
In a multi-neck flask equipped as described in Example 6, a reac-tion mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 2% by weight of bis(trimethylsi-10 lyl)~m;ne (hexamethyldisilazane) was heated to 110 C under a ni-trogen atmosphere and was cyclized for 12 hours at this tempera-ture while stirring. 0.2% by weight, based on the weight of BEP-DI, of n-butanol was then added to the reaction mixture and the reaction mixture was stirred for a further 30 minutes at 110 C.
15 The reaction mixture obtained, which had an isocyanate content of 28.9~ by weight, was subjected to thin-film distillation under reduced pressure to ~~ -ve the unreacted BEPDI.
This gave a clear, yellowish, amorphous polyisocyanate mixture 20 contA; n; ng isocyanurate and uretdione groups and having a sig-nificantly narrower molecular weight distribution than in Example ? and having an isocyanate content of 16.9% by weight, the GPC chromatogram of which is shown in Figure 2.
25 The selectivity or reactivity of the primary isocyanate group ~;~
compared with that of the isocyanate group having a neo-con-figuration, determined by lH-NMR spectroscopy, is, for BEPDI and using trimethyl-2-hydroxypropylammonium 2-ethylhexanoate as trimerization catalyst, about 3:1 (Example 7) and, using bis(tri-30 methylsilyl)amine as trimerization catalyst, about 8:1 (Example 8).
Comparative Examples 35 Preparation of polyisocyanate mixtures containing isocyanurate \ and uretdione groups and based on HDI, TMHDI and IPDI.
Comparative Example I
40 500 parts by weight of HDI having an isocyanate content of 50~ by weight and 2% by weight, based on the weight of HDI, of bis(tri-methylsilyl)amine (hexamethyldisilazane) were mixed at 80 C under a nitrogen atmosphere in a multi-neck flas~ equipped as described in Example 6, the reaction mixture waR then heated to 110 C and 45 cyclized for 5 hours at thi~ temperature while stirring. 1.5% by weight, based on the weight of HDI, of n-butanol were then added to the reaction mixture and the reaction mixture was stirred for `- `` 213953~
, a further 30 minutes at 110 C. The reaction mixture obtained, which had an isocyanate content of 41.2% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted HDI.
This gave a clear, viscous polyisocyanate mixture cont~; n; ng iso-cyanurate and uretdione groups and having an isocyanate content of 22.9% by weight and a viscosity at 23 C of 1800 mPas.
lO Comparative Example II
500 parts by weight of TMHDI having an isocyanate content of 40%
by weight and 2% by weight, based on the weight of TMHDI, of bis(trimethylsilyl)amine (hexamethyldisilazane) were mixed at 80 C
15 under a nitrogen atmosphere in a multi-neck flask equipped as described in Example 6, the reaction mixture was then heated to 110 C and cyclized for 12 hours at this temperature while stir-ring. 1.0% by weight, based on the weight of TMHDI, of n-butanol were then added to the reaction mixture and the reaction mixture 20 was stirred for a further 30 minutes at 110 C. The reaction mix-ture obtained, which had an isocyanate content of 28.9% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted TMHDI.
25 This gave a yellowish, clear, viscous polyisocyanate mixture con-taining isocyanurate and uretdione groups and having an isocya-nate content of 19% by weight and a viscosity at 23 C of 7600 mPas.
30 Comparative Example III
500 parts by weight of IPDI havinq an isocyanate content of 37.8%
by weight and 2% by weight, based on the weight of IPDI, of bis(trimethylsi~yl)amine (hexamethyldisilazane) were mixed at 80 C
35 under a nitrogen atmosphere in a multi-neck flask equipped as de-\ scribed in Example 6, the reaction mixture was then heated to 110 C and cyclized for 7 hours at this temperature while stirring.
1.0% by weight, based on the weight of IPDI, of n-butanol were then added to the reaction mixture and the reaction mixture was 40 stirred for a further 30 minutes at llO C. The reaction mixture obtained, which had an isocyanate content of 29.2% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted IPDI.
` 2139~3~
.
This gave a yellowish, clear, viscous polyisocyanate mixture con-t~;ning isocyanurate and uretdione groups and having an isocya-nate content of 17.3% by weight, which crystallized on standing at room temperature and then had a melting range from 90 to 100 C.
,- The distribution of the cylic and linear oligomers in the poly-isocyanate mixtures cont~;n;ng isocyanurate and uretdione groups prepared at a diisocyanate conversion of about 30~ in accordance with Example 8 and Comparative Examples I to III, determined by 10 the percentage areas in gel permeation chromatography (GPC), are -rized in the table below.
In the table: .
15 Isocyanurate (1~ triisocyanate cont~;ning isocyanurate groups, obtained from 3 mol of diisocyanate Isocyanurate (2): is tetrai~ocyanate cont~;n;ng diisocyanurate groups, obtained from 5 mol of diisocyanate Isocyanurate (3): is polyisocyanates cont~;n;ng oligomeric isocyanurate groups, obtained from at least 6 mol of diisocyanate.
25 Table - , ~-Example 8 Comparative Example I II III
30 Diisocyanate BEPDI HDI TMHDI IPDI
Isocyanurate (1) 80 53 50 50 [percentage area]
Isocyanurate (2) 10 19 18 10 [percentage area]
35 Isocyanurate (3) 5 18 18 5 ~percentage area]
Byproducts, includ- 5 10 14 35 ing uretdione groups [percentage area]
~0 The high selectivity of the BEPDI which can be used according to the invention is shown by the high content of triisocyanate con-t~ i n; ng isocyanurate groups (isocyanurate (1)) combined with the 45 low content of polyisocyanates cont~; n; ng at least 2 isocyanurate .rings and of byproducts (Example 8).
.
Modified (cyclo)aliphatic polyisocyanate mixtures, preparation thereof and use thereof 5 The present invention relates to polyisocyanate compositions modified by urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and having an isocyanate content of from 1 to 34~ by weight, based on the total weight, which are prepared from diisocyanates having isocyanate groups of 10 differing reactivity selected from the group consisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopro-pyl)cyclohexyl-l-isocyanate and/or l-(isocyanatomethyl)-1-(3-iso-cyanatopropyl)cyclohexane, a process for the preparation thereof and use thereof.
It is known that polyisocyanate polyaddition products can be pre-pared by reaction of organic polyisocyanates with compounds con-taining hydrogen atoms which react with NCo groups, such as the hydrogen atoms of hydroxyl, amino, mercapto or carboxyl groups, 20 in the presence or absence of catalysts, solvents and other addi-tives. It is frequently advantageous or even necessary to modify the organic polyisocyanates prior to their use for the formation of polyisocyanate polyaddition products for specific applica-tions. Reasons for this can be, for example, the lowering of the 25 vapor pressure, a change in the viscosity and thus their processibility, the functionality and the reactivity and also, in particular, the achievement of specific mechanical properties in the final products. The modification is carried out by a partial chemical alteration of the isocyanate groups, so that relatively 30 high-molecular-weight polyisocyanate compositions still having free, reactive isocyanate groups result. As industrially most im-portant modification reactions, mention may be made of, for ex-ample, the dimerization and trimerization to give uretdione and isocyanurate groups and the formation of carbodiimide, biuret, 35 urea, urethane and/or allophanate groups. By means of suitable catalysts and reaction conditions, it is generally possible to achieve a selective modification.
For the preparation of such polyisocyanate mixtures containing 40 urethane, allophanate, urea, biuret, carbodiimide, uretdione and~
or isocyanurate groups, it is possible to react, for example, al-iphatic or cycloaliphatic diisocyanates or mixtures of aliphatic and cycloaliphatic diisocyanates in the presence of a suitable catalyst in the absence of solvent or with addition of a solvent 45 and, if desired, an additive, advantageously at elevated tempera-tures, for example at from 60 to 140 C, until the desired conver-sion is achieved. Subsequently, the catalysts can be deactivated 213953~
thermally and/or by addition of a catalyst poison and, if desired, the excess monomeric (cyclo)aliphatic diisocyanates and any solvents added can be separated off. The separation is pre-ferably carried out by distillation under reduced pressure by 5 means of a thin-film evaporator. Modified polyisocyanate mixtures - prepared by such processes can be reacted with relatively high-molecular-weight and/or low-molecular-weight polyhydroxyl com-pounds, eg. polyether polyols, polyester polyols or polyhydroxya-crylates, to give NCO-cont~ining prepolymers. Furthermore, the 10 isocyanate groups of the modified polyisocyanate compositions or NCO prepolymers can be capped or blocked. For this purpose, the NCO groups are reacted with compounds which can relatively easi-ly, advantageously at elevated temperature, be cleaved off again to give NCo groups. The reactive isocyanate group thus liberated 15 can then react further in a known manner, eg. with hydroxyl or amino groups. Suitable capping agents are, for example, phenols, caprolactam, B-dicarbonyl compounds such as acetoacetic esters, dialkylmalonates, oximes, triazoles and certain alcohols. Modi-fied and/or blocked polyisocyanate mixtures are used, in particu-20 lar, in high-performance single-component and two-component sys-tems for finishes and coatings.
Use of organic polyisocyanates containing isocyanate groups of differing reactivity, eg. (cyclo)aliphatic diisocyanates such as 25 2-ethylbutane-1,4-diisocyanate, 2-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexane-1,6-diisocyanate (TMHDI) or isocyanatome-thyl-3,5,5-trimethylcyclohexylisocyanate (IPDI), enables, by reaction of the more reactive isocyanate group, the pre?aration of modified polyisocyanate mixtures having reduced reactivity, 30 which mixtures have relatively long processing times.
There have therefore been many attempts, by means of appropriate modification of (cyclo)aliphatic diisocyanates having isocyanate groups of differing reactivity, to improve their shelf life, pro-35 cessibility and the mechanical properties of polyisocyanate poly-addition products prepared therefrom.
According to EP-A-O 045 995 (US-A-4 476 054), isocyanurate-free uretdiones can be prepared from IPDI in the presence of a cata-40 lyst of the formula XmP(NR2)3_m, where m is 0, 1 or 2, X is Cl, ORor R and R are identical or different alkyl, benzyl, phenylethyl, cyclohexyl and cyclopentyl radicals. Such IPDIs containing uret-dione groups can be reacted with diols and, if desired, with monoalcohols or monoamines in accordance with EP-A-O 045-996 - -~~-45 (US-A-4 483 798) to give polyaddition products containing uret-dione groups, which products can, according to EP-A-O 045 997 (US-A-4 430 474), be used for the production of stoving enamels.
-`` 213953~
, Isocyanatouretdiones and a process for the preparation thereof using 2-methyl-1,5-diisocyanatopentane and 2-ethyl-1,4-diisocya-natobutane as suitable starting materials are also described in EP-A-O 099 976 (US-A-4 668 780). The polyisocyanates containing 5 uretdione groups are intermediates for producing plastics, finishes and foam materials.
Isocyanatoisocyanurates and processes for the preparation thereof or the preparation of ~torage-stable solutions thereof are 10 described in EP-B-0 082 987 (US-A-4 469 867) and DE-B-2 325 826 (US-A-3 919 218). According to EP-A-0 082 987, isocyanatoisocya-nurates are prepared by partial trimerization of 2-methyl-1,5-diisocyanatopentane or mixtures of 2-meth-yl-1,5-diisocyanatopentane and 2-ethyl-1,4-diisocyanatobutane.
15 According to DE-B-23 25 826, IPDI or 2,2,4- or 2,4,4-TMHDI are used as (cyclo)aliphatic diisocyanates.
Polyisocyanates cont~i n; ng biuret ylG~pS derived from 2-meth-yl-1,5-diisocyanatopentane or 2-ethyl-1,4-diisocyanatobutane are 20 described in EP-A-0 082 973.
Disadvantages of the modified polyisocyanates described are their nonuniformity in respect of their chemical structure and the reactivity of the free isocyanate groups. This nonuniformity is 25 caused by the small reactivity differences between the two iso-cyanate groups of the (cyclo)aliphatic diisocyanates specified as starting materials. A further mechanical property, undesirable for certain applications, results from the rigidity of the IPDI
molecule caused by the structure.
It is an object of the present invention to prepare modified polyisocyanate mixtures having, in comparison with known prod-ucts, more uniform molecular composition, reduced reactivity and increased processing time.
We have found that this object is achieved by modification of (cyclo)aliphatic diisocyanates having differing reactivity of the isocyanate groups, caused by their specific chemical structure.
40 The invention accordingly provides a polyisocyanate mixture con-t~ining urethane, allophanate, urea, biuret, carbodiimide, uret-dione and/or isocyanurate groups and having an isocyanate content of from 1 to 34% by weight, which is prepared by known processes from (cyclo)aliphatic diisocyanates selected from the group con-g5 sisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocya-natopropyl)cyclohexyl-1-isocyanate, l-(isocyanatomethyl)-213953~
..
1-(3-isocyanatopropyl)cyclohexane and mixtures of at least two of the specified (cyclo)aliphatic diisocyanates.
It has surprisingly been found that the reactivity differences 5 between the isocyanate groups of the (cyclo)aliphatic diisocyan-- ates which can be used according to the invention are, because of the specific substituents and their influence on the immediate steric environment, substantially more pronounced than in the known, ab~v. -ntioned (cyclo)aliphatic diisocyanates.
For example, 2-(3-isocyanatopropyl~cyclohexylisocyanate has a sterically unhindered primary isocyanate group on the propylene radical and a secondary isocyanate group on the cyclohexane ring, while in IPDI the primary isocyanate group is bonded to the 15 cyclohexane ring with only a methylene bridge (neo-group) in between.
Owing to its flexible structure, 2-butyl-2-ethylpentane-1,5-di-isocyanate has advantageous processing properties and gives poly-20 isocyanate polyaddition products having excellent mechanicalproperties. The primary isocyanate group on the C5 atom is sepa-rated from the lateral 2-ethyl and 2-butyl radicals by a propy-lene bridge and i~ therefore more reactive than the isocyanate group on the C1 atom which is sterically hindered by a neo-group 25 and is thereby deactivated. ;
Since in the reaction for modifying the (cyclo)aliphatic diisocy-anates which can be used according to the invention the more reactive primary isocyanate group reacts preferentially, the 30 polyisocyanate mixtures modified according to the invention have a reduced reactivity and, as a result, a longer processing time than polyisocyanate mixtures based on HDI, TMHDI or IPDI and mod-ified with similar groups.
35 As has already been indicated, l-(isocyanatomethyl)-1-(3-isocya-natopropyl)cyclohexane is suitable for the preparation of the polyisocyanate mixtures modified according to the invention. How-ever, the (cyclo)aliphatic diisocyanates preferably used are 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate (abbreviated to 40 IPCI) and, in particular, 2-butyl-2-ethylpentane-1,5-diisocyanate (abbreviated to HEPDI). The (cyclo)aliphatic diisocyanates which can be used according to the invention can be prepared by any processes, eg. by phosgenization of the corresponding (cyclo)ali-phatic diamines to give the corresponding dicarbamic acid 45 chloride~ and their thermal cleavage into the (cyclo)aliphatic diisocyanates and hydrogen chloride. However, preference is given to using (cyclo)aliphatic diisocyanates, in particular IPCI and 213~53S
BEPDI, which are obtainable by phosgene-free processes, in par-ticular by thermal cleavage of (cyclo)aliphatic dicarbamic esters into the (cyclo)aliphatic diisocyanates and alcohols. This ther-mal cleavage can be carried out, for example, at temperatures of 5 from lS0 to 300 C, preferably from 180 to 250 C and pressures of - from 0.001 to 2 bar, preferably from 1 to 200 mbar, in the ab-sence or preferably the presence of catalysts in suitable cleavage reactors, such as thin-film or preferably heater-plug evaporators. The (cyclo)aliphatic diisocyanates and alcohols 10 formed in the cleavage can be separated, for example, by frac-tional condensation or preferably by rectification and the (cyclo)aliphatic diisocyanates can be additionally purified, for example, by distillation.
15 The preparation of the polyisocyanate mixtures of the invention contAining urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and baQed on l-(isocyanato-methyl)-l-(3-isocyanatopropyl)cyclohexane, preferably IPCI and in particular ~EPDI is carried out by methods known per se by means 20 of catalyst-free or preferably catalytic oligomerization and/or polycondensation of the (cyclo)aliphatic diisocyanates which can be used according to the invention and~or polyaddition of these diisocyanates and/or the polyisocyanate mixtures modified accord-ing to the invention to compounds having at least one reactive 25 hydrogen atom, preferably water, monofunctional and/or polyfunc-tional alcohols and/or monofunctional and/or polyfunctional amines.
After reaching the desired content of carbodiimide, uretdione 30 and/or isocyanurate groups in the reaction mixture or the desired degree of reaction, which can, for example, be measured by deter-mining the isocyanate content of the reaction mixture, the reac-tion can be stopped by deactivating the catalyst, for example by addition of a catalyst poison or by thermal decomposition of the 35 catalyst. If monomer-free, modified polyisocyanate mixtures are required for particular fields of application, such as single-component or two-component polyurethane finishes, the unreacted monomeric diisocyanates can be removed in an appropriate manner known per se, eg. by distillation, for example by means of a 40 thin-film evaporator.
To prepare polyisocyanate mixtures contA;ning urethane and allo-phanate groups, the (cyclo)aliphatic diisocyanates which are suitable according to the invention can be reacted with alcohols, 45 preferably alkanediols in the required amounts, advantageously in amounts of, for example, from 0.005 to 0.4, preferably from O.OS
to 0.15, equivalents of hydroxyl group per equivalent of .`` 213g53~ -.
isocyanate group. Polyi50cyanate mixtures cont~;ning urea and/or biuret groups can be obtained by reaction of the (cyclo)aliphatic diisocyanates, which can be used according to the invention, with water, compounds from which water can be cleaved, such as tertia-5 ry butanol or salts cont~;n;ng water of crystallization, and pri-mary and secondary amines, preferably aliphatic and/or aromatic diamines. ~hen using a tertiary monoalkanol as the compound from which water can be cleaved, the molar ratio of diisocyanates to alcohol is usually at least 2.5:1, preferably at least 8:1.
Similar processes for preparing the polyisocyanate mixtures modi-fied according to the invention are de~cribed in literature pub-lications such as the ~unststoff-Handbuch, Volume 7, Polyurethane, Carl Hanser Verlag, 1st and 2nd Edition (1966 and 15 1983 respectively), and, in particular, patents.
For example, preparation processes are described for polyisocya-nate mixtures cont~; n; ng urethane groups in DE-B-1 618 380 (US-A-3 644 457), DE-A-25 13 793 (GB-A-14 50 660) or EP-A-10 850 20 (US-A-4 261 852), for polyisocyanate mixtures cont~;n;ng allopha-nate and isocyanurate groups in EP-A-0 566 037, for polyisocya-nate mixtures contA~n;ng urea and/or biuret groups in DE-B-1 101 394 (GB 876 503), DE-B-1 070 374, GB-A-889 050, DE-B-l 227 003 (US-A-3 284 479), DE-A-l 174 759, (US-A-3 392 183) 25 and DE-A-l 543 178 (GB-A-1 044 932), for polyisocyanate mixtures containing carbodiimide groups in DE-A-1 130 594 (US-A-2 941 966), GB-A-1 083 410, US-~-2 941 983 and DE-B-22 48 751 (US-A-4 076 945), for pclyisocyanate mixtures con-taining uretdione groups in DE-A-1 643 170 (US 3 489 744) and 30 DE-A-1 081 895 (GB-A-821 158) and for, in particular, polyisocya-nate mixtures containing isocyanurate groups in DE-A-26 16 415, US-A-3 645 979, US-3 248 372 and GB-A-837 120.
The (cyclo)aliphatic diisocyanates l-(isocyanatomethyl)-1-(3-iso-35 cyanatopropyl)cyclohexane, preferably IPCI and, in particular, BEPDI which can be used according to the invention are used to prepare, in particular, polyisocyanate mixtures modified by iso-cyanurate groups, since these are very useful for preparing high-performance single-component or two-component polyurethane (PU) 40 adhesive~ or, in particular, finishes.
To prepare the polyisocyanate mixtures of the invention contain-ing isocyanurate groups, the (cyclo)aliphatic diisocyanates which can be used according to the invention are partially cyclized in 45 a conventional manner, advantageously under an atmosphere of gases inert under the reaction conditions, such a~ nitrogen, in the presence of at least one trimerization catalyst at `` 213~5~5 _ 7 temperatures of advantageously from 30 to 140 C, preferably from 70 to 120 C. After reaching the desired isocyanurate content or NCO content, which is advantageously in a NCO range ~rom 1 to 34%
by weight, preferably from 10 to 34~ by weight, based on the 5 weight of the reaction mixture containing isocyanurate groups, and, depending on the reaction temperature selected within the specified temperature range, is usually obtained in a period of from 0.1 to 12 hours, preferably from 2 to 5 hours, the trimer-ization catalyst is deactivated by addition of a deactivator and lO the isocyanurate formation is thus stopped. The polyisocyanate mixture obtained cont~ining isocyanurate groups can, for example, be additionally modified by continuous or stepwise addition of compounds having reactive hydrogen atoms, preferably amino or, in particular, hydroxyl compounds, or the monomeric organic diisocy-15 anates can be removed, if desired, prior to or after the addi-tional modification, advantageously by means of a thin-film evaporator under reduced pressure.
To partially cyclize the (cyclo)aliphatic diisocyanates which can 20 be used according to the invention, the usual trimerization cata-lysts, such as tertiary amines, phosphines, alkoxides, metal ox-ides, hydroxides, carboxylates and organometallic c~ ~oul-dg can be used. Other trimerization catalysts which have proven very useful are tris(N,N-dialkylaminoalkyl)-S-hexahydrotriazines, such 25 as tris(N,N-dimethylaminopropyl)-S-hexahydrotriazine, and organic salts of weak acids with tetraalkylammonium groups or trialkylhy-droxyalkylammonium groups, with preference being given to for example, N,N,N-trimethyl-N-2-hydroxypropylammonium p-tert-butyl-benzoate and N,N,N-trimethyl-N-2-hydroxypropylammonium 2-ethyl-30 hexanoate because they are simple to prepare and to purify. Ithas surprisingly been found that the type of catalyst can also effect an additional selective trimerization; in comparison to tetraalkylammonium carboxylates, the use of silylamines, prefer-ably of bis(trimethylsilyl)amine, preferentially activates the 35 more reactive primary isocyanate group. Since this selective trimerization makes the molecular structure and reactivity more uniform, particular preference is given to using silylamines as catalysts for preparing the polyisocyanate mixtures containing isocyanurate groups. The trimerization catalysts, which can also 40 effect the formation of uretdione groups and oligomeric isocyanurate groups as byproducts, are usually used in an amount of from 0.001 to 0.5% by weight, preferably from 0.01 to 0.05% by weight, based on the weight of the organic diisocyanates.
45 As has already been indicated, the trimerization catalysts are usually deactivated after formation of the desired amount of isocyanurate groups. Suitable deactivators in case of the ` 213953S
.
first-mentioned ionic catalysts are, for example, inorganic or organic acids, the corresponding acid halides and alkylating agents. Examples which may be mentioned are phosphoric acid, mo-nochloroacetic acid, dodecylbenzenesulfonic acid, benzoyl chlo-5 ride, dimethyl sulfate and preferably dialkyl phosphates, in par-ticular dibutyl phosphate. To deactivate the silylamine cata-lysts, use is preferably made of monofunctional and difunctional alcohols such as n-butanol, n-hexanol, 1,2-propanediol and~or 1,4-butanediol. The deactivators can be used in amounts of from 1 10 to 300 mol%, preferably from 50 to 150 mol%, based on the number of moles of trimerization catalyst.
Although the polyisocyanates containing isocyanurate and, if de-sired, uretdione groups would also be able to be prepared using 15 inert solvents or diluents, these are preferably not used in the process of the invention for ecological and economic reasons.
The polyisocyanate mixtures of the invention cont~; n; ng isocya-nurate groups advantageously contain at least 50% by weight, pre-20 ferably at least 60% by weight and in particular at least 70% byweight, based on the isocyanurate-polyisocyanates, of polyiso-cyanates of the formula i~
\
213953~
R ~ R
0 - C ~ ~ =
N
R
10 where R is a radical selected from the group consisting of y 15 -CH2-CH2-CH2 CH2-NCO , preferably 20 -CH2-CH2-CH2 ~ and in particular C2Hs I
25 -CH2-CH2-CH2-C-CH2-NC0 t C4Hg The polyisocyanate mixtures of the invention containing urethane, 30 allophanate, urea, biuret, carbodiimide, uretdione and/or iso-cyanurate groups have an isocyanate content in the range from 1 to 34% by weight, based on the total weight. According to pre-ferred embodiments, the polyisocyanate mixtures containing ure-thane groups preferably have an isocyanate content of from 1 to 35 30% by weight, in particular from 1.5 to 26% by weight, the poly-isocyanate mixtures cont~;n;ng allophanate groups preferably have an isocyanate content of from 1 to 30% by weight, in particular from 1.5 to 26% by weight, the polyisocyanate mixtures cont~;n;ng urea groups preferably have an isocyanate content of from 1 to 40 30% by weight, in particular from 3 to 26% by weight, the poly-isocyanate mixtures containing biuret groups preferably have an isocyanate content of from 5 to 34% by weight, in particular from 5 to 25% by weight, the polyisocyanate mixtures cont~;n;ng carbo-- diimide groups preferably have an isocyanate-content of from 2 to-45 33% by weight, in particular from 5 to 30% by weight, the poly-- isocyanate mixtures cont~i ni ng uretdione groups preferably have an isocyanate content of from 5 to 33% by weight, in particular ` ~1395~5 from lO to 30% by weight, and the polyisocyanate mixtures con-t~i ni ng isocyanurate groups preferably have an isocyanate content of from 10 to 34~ by weight, in particular from 10 to 30% by weight, with the percentages by weight being in each case based 5 on the total weight of the polyisocyanate mixtures. If the poly-isocyanate mixtures modified according to the invention were mo-dified with more than one of the groups relevant to the inven-tion, eg. a uretdione and an isocyanurate group, a carbodiimide and an isocyanurate group, a urethane and an isocyanurate group, 10 a urethane and an allophanate group, a urethane and at least one carbodiimide group or a urea and a biuret group, the isocyanate contents are likewise within the isocyanate percentage region specified above for one group.
15 The polyisocyanate mixtures modified according to the invention can be used in the form obtained or be diluted prior to proces-sing with a solvent inert towards isocyanate groups, eg. for re-ducing the viscosity and improving the flowability. The type of solvent which may, if desired, be advantageously used is usually 20 also dependent on the application of the polyisocyanate mixtures modified according to the invention. Suitable solvents are, for example, those solvents and diluents which are inert towards iso-cyanate groups and are usual in the surface coatings and adhe-sives industry.
f~'`
The polyisocyanate mixtures of the invention cont~ining urethane, allophanate, biuret, carbodiimide, uretdione and/or isocyanurate groups are useful, for example, for preparing polyurethane finish systems, such as single-component or t~v co...ponent finishes, 30 polyurethane coatings, dispersions, adhesives such as single-com-ponent or two c~.,.ponent adhesives, polyurethane sealants, cellu-lar or compact polyurethane elastomers, casting elastomers and foam materials such as flexible, semi-rigid or rigid block or shaped foam materials and also the corresponding integral foam 35 materials.
\
Examples The viscosity specified in the examples was measured in accord-40 ance with DIN 53019 using a rotation viscometer at 23 C.
In the examples and comparative examples, use was made of the following diisocyanates as they were abbreviated in the descrip-tion of the invention:
213g~35 HDI: 1,6-hexamethylenedii50cyanate (1,6-diisocyanatohexane), TMHDI: 2,2,4-trimethylhexamethylene-1,6-diisocyanate, IPDI: 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophoronediisocyanate), S IPCI: 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate and ~EPDI: 2-butyl-2-ethylpentane-1,5-diisocyanate.
Example 1 10 Preparation of a polyisocyanate mixture containing biuret groups and based on IPCI.
500 parts by weight of IPCI having an NC0 content of 40.3% by weight and 15 parts by weight of tert-butanol were mixed with 15 stirring in a multi-neck flask fitted with stirrer, reflux con-denser and septum, and the reaction mixture was heated to 160 C.
0.5 parts by weight of para-toluenesulfonic acid, dissolved in 2.8 parts by weight of tert-butanol, were added dropwise to the 20 reaction mixture over a period of 10 minutes. Vigorous evolution of carbon dioxide and isobutene commenced, this stopping after about 30 minutes. To complete the reaction, the reaction mixture was stirred for a further 60 minutes at 160 C, then allowed to cool to room temperature and degasqed for 30 minutes at room tem-25 perature under reduced pressure (about 20 mbar). The polyisocya-nate mixture obtained, which had an isocyanate content of 32.9%
by weight, was subjected to distillation using a thin-film evap-orator to remove the unreacted monomer IPCI.
30 This gave a viscous, yellow polyisocyanate mixture containing biuret and uretdione groups and having an isocyanate content of 19.7% by weight and a viscosity at 23 C of greater than 10 000 mPas.
35 Example 2 Preparation of a polyisocyanate mixture cont~i n; ng biuret groups and based on BEPDI.
40 The procedure of Example 1 was repeated, but the starting materi-als used were 700 parts by weight of ~EPDI having an isocyanate content of 34.8~ by weight, 24 part~ by weight of tert-butanol and 0.7 parts by weight of para-toluenesulfonic acid dissolved in 2.0 parts by weight of tert-butanol.- ~ ~
`` 21395~
The polyisocyanate mixture obtained, which had an isocyanate con-tent of 20.3% by weight, was subjected to distillation using a thin-film evaporator to remove the unreacted monomer BEPDI.
5 This gave a viscous, yellow polyisocyanate mixture containing biuret groups and having an isocyanate content of 16.1% by weight and a viscosity at 23 C of greater than 10 000 mPas.
Example 3 Preparation of a polyisocyanate mixture cont~; n; ng urethane and allophanate groups and based on BEPDI.
500 parts by weight of ~EPDI having an isocyanate content of 15 34.8% by weight, 31.1 parts by weight of n-butanol and 0.27 parts by weight of copper(II) acetylacetonate were mixed under a nitro-gen atmosphere in a multi-neck flask fitted with stirrer, gas in-let and outlet, reflux condenser and septum, the reaction mixture was heated to 80 C and reacted at this temperature for 6 hours. To 20 the reaction mixture obtained, which had an isocyanate content Gf 23.6~ by weight, there was added 0.44 part by weight of dibutyl phosphate and the unreacted BEPDI was subsequently distilled off under reduced pressure (about 3 mbar) by means of a thin-film evaporator.
This gave an oily polyisocyanate mixture cont~;ning urethane and allophanate groups and having an isocyanate content of 15.2~ by weight and a viscosity at 23 C of 6140 mPas.
30 Example 4 Preparation of a polyisocyanate mixture containing allophanate and isocyanurate groups.
35 A mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 13.8 parts by weight of 2-ethyl-hexanol was heated to 100 C under a nitrogen atmosphere in a multi-neck flask equipped as described in Example 3, and reacted at this temperature for one hour. The reaction mixture, which was 40 allowed to cool to 80 C, then had an isocyanate content of 32.9 by weight.
At this temperature, 0.2~ by weight, based on the weight of the ~EPDI used, of trimethyl-2-hydroxypropylammonium 2-ethylhexanoate 45 was added to the reaction mixture as trimerization catalyst, the mixture was stirred at 80 C for 4 hours and the trimerization cat-alyst was deactivated by addition of 0.2~ by weight of dibutyl 213~535 _ 13 phosphate, based on the weight of the BEPDI used. The reaction mixture obtained, which had an isocyanate content of 27% by weight, was subjected to distillation using a thin-film evapora-tor to remove the monomeric BEPDI.
This gave a clear, yellowish polyisocyanate mixture containing allophanate and isocyanurate groups and having an isocyanate con-tent of 14.3~ by weight and a viscosity at 23 C of greater than 10 000 mPas.
Example 5 Preparation of a polyisocyanate mixture cont~ining isocyanurate and urethane groups To 500 parts by weight of BEPDI in a multi-neck flask equipped as described in Example 3, there was added 0.2~ by weight, based on the BEPDI, of trimethyl-2-hydro~ypropylammonium 2-ethylhexanoate, the reaction mixture was heated to 80 C under a nitrogen atmos-~0 phere and the BEPDI was cyclized at this temperature for 4 hours.The trimerization catalyst was then deactivated by addition of 0.2~ by weight of dibutyl phosphate, based on the weight of BEPDI, and the reaction mixture, which had an isocyanate content of 29.4~ by weight, was reacted with 13.8 parts by weight of 25 2-ethylhexanol. After a further reaction time of 2 hours at 80 C, ~F-the reaction mixture had an isocyanate content of 27.2~ by weight. After distilling off the unreacted monomeric BEPDI by mear.s of thin-film distillation under reduced pressure, there was obtained a clear, yellowish polyisocyanate mixture containing 30 isocyanurate and urethene groups and having an isocyanate content of 13.5% by weight and a viscosity at 23 C of greater than 10 000 mPas.
EXample 6 Preparation of a polyisocyanate mixture cont~in;ng isocyanurate and uretdione groups.
In a multi-neck flask fitted with stirrer, reflux condenser and 40 gas inlet and outlet, a reaction mixture of 500 parts by weight of IPCI having an isocyanate content of 40.3~ by weight and 0.1 by weight, based on the weight of IPCI, of trimethyl-2-hydroxy-propylammonium 2-ethylhexanoate was heated to 80 C under a nitro-gen atmosphere and was cyclized for 3 hours at~-this temperature 45 while stirring. The trimerization catalyst was deactivated by addition of 0.1~ by weight of dibutyl phosphate, based on the weight of IPCI. The reaction mixture, which had an isocyanate 2139~35 -. .` .
content of 33% by weightl was subjected to thin-film distillation under reduced pressure to remove the unreacted IPCI.
This gave a clear, yellowish polyisocyanate mixture containing 5 iQocyanurate and uretdione groups and having an iQocyanate con-tent of 19.3% by weight and a viscosity at 23 C of greater than 10 000 mPas.
The polyisocyanate mixture cont~;ning isocyanurate and uretdione 10 groups was, to make further processing easier, diluted with n-butyl acetate to give a 90% by weight strength solution which had an isocyanate content of 17.3% by weight and a viscosity at 25 C of 480 mPas.
15 Example 7 Preparation of a polyisocyanate mixture contA;n;ng isocyanurate and uretdione groups 20 In a multi-neck flask equipped as described in Example 6, a reac-tion mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 0.2% by weight, based on the weight of BEPDI, of trimethyl-2-hydroxypropylammonium 2-ethylhex-anoate was heated to 80 C under a nitrogen atmosphere and cyclized 25 for 4 hours at this temperature while stirring. The trimerization catalyst was deactivated by addition of 0.2% by weight of dibutyl phosphate, based on the weight of BEPDI. The unreacted BEPDI was distilled out of the reaction mixture by means of thin-film dis-tillation under reduced pressure.
This gave a clear, yellowish, amorphous polyisocyanate mixture cont~;n;ng isocyanurate and uretdione groups and having an isocy-anate content of 15.5% by weight, the GPC chromatogram of which is shown in Figure 1.
\ The polyisocyanate mixture containing isocyanurate and uretdione groups was, for easier further processing, diluted with n-butyl acetate to give a 90% by weight strength solution which had an isocyanate content of 14.3% by weight and a viscosity at 25 C of 40 440 mPas.
`` 213~3~
, .
Example 8 Preparation of a polyisocyanate mixture cont~in;ng isocyanurate 5 and uretdione groups.
In a multi-neck flask equipped as described in Example 6, a reac-tion mixture of 500 parts by weight of BEPDI having an isocyanate content of 34.8% by weight and 2% by weight of bis(trimethylsi-10 lyl)~m;ne (hexamethyldisilazane) was heated to 110 C under a ni-trogen atmosphere and was cyclized for 12 hours at this tempera-ture while stirring. 0.2% by weight, based on the weight of BEP-DI, of n-butanol was then added to the reaction mixture and the reaction mixture was stirred for a further 30 minutes at 110 C.
15 The reaction mixture obtained, which had an isocyanate content of 28.9~ by weight, was subjected to thin-film distillation under reduced pressure to ~~ -ve the unreacted BEPDI.
This gave a clear, yellowish, amorphous polyisocyanate mixture 20 contA; n; ng isocyanurate and uretdione groups and having a sig-nificantly narrower molecular weight distribution than in Example ? and having an isocyanate content of 16.9% by weight, the GPC chromatogram of which is shown in Figure 2.
25 The selectivity or reactivity of the primary isocyanate group ~;~
compared with that of the isocyanate group having a neo-con-figuration, determined by lH-NMR spectroscopy, is, for BEPDI and using trimethyl-2-hydroxypropylammonium 2-ethylhexanoate as trimerization catalyst, about 3:1 (Example 7) and, using bis(tri-30 methylsilyl)amine as trimerization catalyst, about 8:1 (Example 8).
Comparative Examples 35 Preparation of polyisocyanate mixtures containing isocyanurate \ and uretdione groups and based on HDI, TMHDI and IPDI.
Comparative Example I
40 500 parts by weight of HDI having an isocyanate content of 50~ by weight and 2% by weight, based on the weight of HDI, of bis(tri-methylsilyl)amine (hexamethyldisilazane) were mixed at 80 C under a nitrogen atmosphere in a multi-neck flas~ equipped as described in Example 6, the reaction mixture waR then heated to 110 C and 45 cyclized for 5 hours at thi~ temperature while stirring. 1.5% by weight, based on the weight of HDI, of n-butanol were then added to the reaction mixture and the reaction mixture was stirred for `- `` 213953~
, a further 30 minutes at 110 C. The reaction mixture obtained, which had an isocyanate content of 41.2% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted HDI.
This gave a clear, viscous polyisocyanate mixture cont~; n; ng iso-cyanurate and uretdione groups and having an isocyanate content of 22.9% by weight and a viscosity at 23 C of 1800 mPas.
lO Comparative Example II
500 parts by weight of TMHDI having an isocyanate content of 40%
by weight and 2% by weight, based on the weight of TMHDI, of bis(trimethylsilyl)amine (hexamethyldisilazane) were mixed at 80 C
15 under a nitrogen atmosphere in a multi-neck flask equipped as described in Example 6, the reaction mixture was then heated to 110 C and cyclized for 12 hours at this temperature while stir-ring. 1.0% by weight, based on the weight of TMHDI, of n-butanol were then added to the reaction mixture and the reaction mixture 20 was stirred for a further 30 minutes at 110 C. The reaction mix-ture obtained, which had an isocyanate content of 28.9% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted TMHDI.
25 This gave a yellowish, clear, viscous polyisocyanate mixture con-taining isocyanurate and uretdione groups and having an isocya-nate content of 19% by weight and a viscosity at 23 C of 7600 mPas.
30 Comparative Example III
500 parts by weight of IPDI havinq an isocyanate content of 37.8%
by weight and 2% by weight, based on the weight of IPDI, of bis(trimethylsi~yl)amine (hexamethyldisilazane) were mixed at 80 C
35 under a nitrogen atmosphere in a multi-neck flask equipped as de-\ scribed in Example 6, the reaction mixture was then heated to 110 C and cyclized for 7 hours at this temperature while stirring.
1.0% by weight, based on the weight of IPDI, of n-butanol were then added to the reaction mixture and the reaction mixture was 40 stirred for a further 30 minutes at llO C. The reaction mixture obtained, which had an isocyanate content of 29.2% by weight, was subjected to thin-film distillation under reduced pressure (about 20 mbar) to remove the unreacted IPDI.
` 2139~3~
.
This gave a yellowish, clear, viscous polyisocyanate mixture con-t~;ning isocyanurate and uretdione groups and having an isocya-nate content of 17.3% by weight, which crystallized on standing at room temperature and then had a melting range from 90 to 100 C.
,- The distribution of the cylic and linear oligomers in the poly-isocyanate mixtures cont~;n;ng isocyanurate and uretdione groups prepared at a diisocyanate conversion of about 30~ in accordance with Example 8 and Comparative Examples I to III, determined by 10 the percentage areas in gel permeation chromatography (GPC), are -rized in the table below.
In the table: .
15 Isocyanurate (1~ triisocyanate cont~;ning isocyanurate groups, obtained from 3 mol of diisocyanate Isocyanurate (2): is tetrai~ocyanate cont~;n;ng diisocyanurate groups, obtained from 5 mol of diisocyanate Isocyanurate (3): is polyisocyanates cont~;n;ng oligomeric isocyanurate groups, obtained from at least 6 mol of diisocyanate.
25 Table - , ~-Example 8 Comparative Example I II III
30 Diisocyanate BEPDI HDI TMHDI IPDI
Isocyanurate (1) 80 53 50 50 [percentage area]
Isocyanurate (2) 10 19 18 10 [percentage area]
35 Isocyanurate (3) 5 18 18 5 ~percentage area]
Byproducts, includ- 5 10 14 35 ing uretdione groups [percentage area]
~0 The high selectivity of the BEPDI which can be used according to the invention is shown by the high content of triisocyanate con-t~ i n; ng isocyanurate groups (isocyanurate (1)) combined with the 45 low content of polyisocyanates cont~; n; ng at least 2 isocyanurate .rings and of byproducts (Example 8).
Claims (10)
1. A polyisocyanate mixture containing urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and having an isocyanate content of from 1 to 34% by weight, prepared by known processes from diisocyanates se-lected from the group consisting of 2-butyl-2-ethylpen-tane-1,5-diisocyanate, 2-(3-isocyanatopropyl)cyclohex-yl-1-isocyanate, 1-(isocyanatomethyl)-1-(3-isocyanatoprop-yl)cyclohexane and mixtures of the specified diisocyanates.
2. A polyisocyanate mixture containing urethane, allophanate, urea, biuret, carbodiimide, uretdione and/or isocyanurate groups and having an isocyanate content of from 1 to 34% by weight, obtainable from 2-butyl-2-ethylpentane-1,5-diisocya-nate by known processes.
3. A polyisocyanate mixture containing isocyanurate groups and having an isocyanate content of from 10 to 34% by weight, containing at least 50% by weight, based on the isocyanurate-polyisocyanates, of polyisocyanates of the formula , where R is a radical selected from the group consisting of , and .
4. A polyisocyanate mixture containing isocyanurate groups as claimed in claim 3, wherein the radical R is .
5. A polyisocyanate mixture containing urethane groups and hav-ing an isocyanate content of from 1 to 34% by weight, obtain-able by known processes from diisocyanates selected from the group consisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate,1-(isocyanato-methyl)-1-(3-isocyanatopropyl)cyclohexane and mixtures of the specified diisocyanates.
6. A polyisocyanate mixture containing biuret groups and having an isocyanate content of from 5 to 34% by weight, obtainable by known processes from diisocyanates selected from the group consisting of 2-butyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopropyl)cyclohexyl-1-isocyanate,1-(isocyanato-methyl)-1-(3-isocyanatopropyl)cyclohexane and mixtures of the specified diisocyanates.
7. A polyisocyanate mixture containing allophanate and/or ure-thane groups and having an isocyanate content of from 1 to 34% by weight, obtainable by known processes from diisocya-nates selected from the group consisting of 2-butyl-2-ethyl-pentane-1,5-diisocyanate, 2-(3-isocyanatopropyl)cyclohex-yl-1-isocyanate, 1-(isocyanatomethyl)-1-(3-isocyanatopro-pyl)cyclohexane and mixtures of the specified diisocyanates.
8. A process for preparing a polyisocyanate mixture containing isocyanurate groups and having an isocyanate content of from 1 to 34% by weight, which comprises trimerizing at least one diisocyanate selected from the group consisting of 2-bu-tyl-2-ethylpentane-1,5-diisocyanate, 2-(3-isocyanatopro-pyl)cyclohexyl-1-isocyanate and 1-(isocyanato-methyl)-1-(3-isocyanatopropyl)cyclohexane in the presence of bis(trimethylsilyl)amine.
9. A process as claimed in claim 8, wherein the trimerization is carried out at from 30 to 140°C.
10. Use of the polyisocyanate mixture containing urethane, allo-phanate, biuret, carbodiimide, uretdione and/or isocyanurate groups as claimed in any one of claims 1 to 7 for producing polyurethane finish systems, coatings, dispersions, adhe-sives, sealants, cellular or compact polyurethane elastomers and foam materials.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4405054A DE4405054A1 (en) | 1994-02-17 | 1994-02-17 | Modified (cyclo) aliphatic polyisocyanate mixtures, process for their preparation and their use |
| DEP4405054.2 | 1994-02-17 |
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| Publication Number | Publication Date |
|---|---|
| CA2139535A1 true CA2139535A1 (en) | 1995-08-18 |
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ID=6510477
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|---|---|---|---|
| CA002139535A Abandoned CA2139535A1 (en) | 1994-02-17 | 1995-01-04 | Modified (cyclo)aliphatic polyisocyanate mixtures, preparation thereof and use thereof |
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| Country | Link |
|---|---|
| EP (1) | EP0671426A1 (en) |
| JP (1) | JPH0827247A (en) |
| KR (1) | KR950032361A (en) |
| CA (1) | CA2139535A1 (en) |
| DE (1) | DE4405054A1 (en) |
| ZA (1) | ZA951261B (en) |
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| US10590226B2 (en) | 2015-04-21 | 2020-03-17 | Covestro Deutschland Ag | Solids based on polyisocyanurate polymers produced under adiabatic conditions |
| US10597484B2 (en) | 2015-04-21 | 2020-03-24 | Covestro Deutschland Ag | Polyisocyanurate plastics having high thermal stability |
| US10717805B2 (en) | 2015-04-21 | 2020-07-21 | Covestro Deutschland Ag | Process for producing polyisocyanurate plastics |
| US10752723B2 (en) | 2015-04-21 | 2020-08-25 | Covestro Deutschland Ag | Polyisocyanurate polymer and process for the production of polyisocyanurate polymers |
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| FR2804112B1 (en) * | 2000-01-20 | 2004-04-30 | Rhodia Chimie Sa | PROCESS FOR OBTAINING LOW-COLORED BRANCHED ISOCYANATE (S) CYCLOTRIMERS AND COMPOSITION THEREOF |
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| CN111072917B (en) * | 2020-01-02 | 2021-06-29 | 万华化学集团股份有限公司 | Polyisocyanate composition with stable storage and preparation method thereof |
| KR20230033654A (en) | 2020-07-02 | 2023-03-08 | 코베스트로 도이칠란트 아게 | Coatings from polyisocyanurate coatings (RIM) and their use in injection molding processes |
| CN117136205A (en) | 2021-03-29 | 2023-11-28 | 科思创德国股份有限公司 | Polyisocyanurate prepreg and fiber composite component produced therefrom |
| EP4303246A1 (en) | 2022-07-04 | 2024-01-10 | Covestro Deutschland AG | Polyisocyanate mixture |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3625986A (en) * | 1967-12-28 | 1971-12-07 | Nat Distillers Chem Corp | Bis 1, 1 isocyanatoalkyl cycloalkanes |
| DE3227779A1 (en) * | 1982-07-24 | 1984-01-26 | Chemische Werke Hüls AG, 4370 Marl | NEW ISOCYANATO URETDIONE AND A METHOD FOR THE PRODUCTION THEREOF |
| DE4010226A1 (en) * | 1990-03-30 | 1991-10-02 | Basf Ag | NEW 2,2-DIALKYLPENTANE-1,5-DIISOCYANATE, DIURETHANE AND DICARBAMID ACID CHLORIDE, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE |
| US5159045A (en) * | 1990-05-24 | 1992-10-27 | Mitsui Toatsu Chemicals, Inc. | Polyisocyanato-isocyanurate, and preparation process and use of the same |
-
1994
- 1994-02-17 DE DE4405054A patent/DE4405054A1/en not_active Withdrawn
-
1995
- 1995-01-04 CA CA002139535A patent/CA2139535A1/en not_active Abandoned
- 1995-02-09 EP EP95101726A patent/EP0671426A1/en not_active Ceased
- 1995-02-16 ZA ZA951261A patent/ZA951261B/en unknown
- 1995-02-16 JP JP7028472A patent/JPH0827247A/en not_active Withdrawn
- 1995-02-17 KR KR1019950003005A patent/KR950032361A/en not_active Application Discontinuation
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| US11286332B2 (en) | 2015-04-21 | 2022-03-29 | Covestro Deutschland Ag | Hydrophobically modified polyisocyanurate plastic and method for production thereof |
| US11286331B2 (en) | 2015-04-21 | 2022-03-29 | Covestro Deutschland Ag | Hydrophilically modified polyisocyanurate plastic and process for production thereof |
| US11390707B2 (en) | 2015-04-21 | 2022-07-19 | Covestro Deutschland Ag | Polyisocyanurate polymers and process for the production of polyisocyanurate polymers |
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| US11760828B2 (en) | 2017-09-26 | 2023-09-19 | Covestro Deutschland Ag | Two-component system for elastic coatings |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4405054A1 (en) | 1995-08-24 |
| JPH0827247A (en) | 1996-01-30 |
| EP0671426A1 (en) | 1995-09-13 |
| KR950032361A (en) | 1995-12-20 |
| ZA951261B (en) | 1996-08-16 |
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