Classifications

• • 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
  • C08G18/02—Polymeric products of isocyanates or isothiocyanates of isocyanates or isothiocyanates only
  • C08G18/027—Polymeric products of isocyanates or isothiocyanates of isocyanates or isothiocyanates only the polymeric products containing urethodione groups
• • 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
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
  • C07F9/02—Phosphorus compounds
  • C07F9/28—Phosphorus compounds with one or more P—C bonds
  • C07F9/54—Quaternary phosphonium compounds
  • C07F9/5407—Acyclic saturated phosphonium compounds
  • C07F9/5414—Acyclic saturated phosphonium compounds substituted by B, Si, P or a metal
• • 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
  • C08G18/08—Processes
  • C08G18/16—Catalysts
  • C08G18/166—Catalysts not provided for in the groups C08G18/18 - C08G18/26
  • C08G18/168—Organic compounds

Definitions

• the present invention relates to a process for preparing isocyanate homopolymers with a high uretdione group content.
• Isocyanate homopolymers containing uretdione groups have a particularly low viscosity, thus, as crosslinkers, they have relatively good applicabilities in coating compositions with low solvent and a high solid content.
• Catalysts reported in patents mainly include tertiary phosphine compounds, boron trifluoride compounds, and pyridine compounds.
• DE 1670720 discloses a process for preparing isocyanate homopolymers containing uretdione groups by using at least one aliphatically substituted tertiary phosphine or boron trifluoride compound.
• the isocyanate homopolymers obtained by this process have a relatively high uretdione content, however, the conversion rate thereof is low.
• the preparation of polyisocyanates containing uretdione groups are disclosed in CN 1502605 and CN 1660792, in both of which the catalysts used are tertiary phosphines containing cycloalkyl substituent or directly phosphorus-attached cycloalkyl substituent.
• the imperfection lies in that the content of uretdione group highly depends on the conversion rate in the preparation of isocyanate homopolymers containing uretdione groups.
• isocyanate homopolymers with a high uretdione group content can be only obtained under the condition of relatively low conversion rate of isocyanate. Accordingly, a large amount of unreacted raw isocyanate monomers are required to be recovered in the product separation stage, thereby rendering a high processing energy cost.
• US 8134014 discloses a process for preparing polyisocyanates containing uretdione group, in which the catalysts used are aminopyridine compounds substituted by fused ring(s).
• the prepared isocyanate homopolymers have a relatively high uretdione group content, and there is no special limitation on the applicable isocyanates.
• the pyridine compounds used tend to color the products. As a result, there is still a need of developing specific processes, wherein the contents of uretdione groups are high with less dependence on the conversion rate of raw isocyanates, and the chromaticity of products as well as the cost of processing energy is low.
• the object of present invention is to provide a process for preparing isocyanate homopolymers containing uretdione groups, in which the phosphinoboron compounds are used as catalysts to catalyze isocyanate homopolymerization, thereby preparing isocyanate homopolymers containing uretdione groups.
• the isocyanate homopolymers obtained in this process have a high uretdione group content, with an obvious ameliorated dependence on the convention rate of the raw isocyanates, and the chromaticity of products is low as well as the cost of processing energy is prominently reduced.
• a process for preparing isocyanate homopolymers containing uretdione groups which includes:
• R 1; R 2 and R 3 are independently selected from linear or branched Cj-C 2 o alkyl group, optionally substituted C 3 -C 2 o cycloalkyl group, optionally substituted C7-Q5 aralkyl group or optionally substituted C 6 -C ]2 aryl group; and
• R 1 ⁇ R 2 and R 3 are independently selected from methyl, linear or branched C 3 -C 20 alkyl group, alkyl-substituted C 3 -C 20 cycloalkyl group, alkyl-substituted C 7 -C 15 aralkyl group, alkyl-substituted C 6 -C ]2 aryl group or alkoxyl-substituted C 6 -C) 2 aryl group; wherein, the alkyl substituents are selected from C 1 -Q0 linear or branched alkyl group, and the alkoxyl substituents are selected from Q-C J O alkoxyl group.
• R 1; R 2 and R 3 are independently selected from methyl, n-butyl, tert-butyl, cyclopropyl, cyclohexyl, phenyl or methoxyphenyl.
• the phosphinoboron compound catalysts of formula (I) in the present invention are preferably selected from one, two or more of the following catalysts:
• the raw isocyanate monomer of the present invention is selected from one of the following compounds: aliphatic isocyanate, cycloaliphatic isocyanate or aromatic isocyanate; wherein the i socyanate having a NC O functionality >2.
• the raw isocyanate monomers of the present invention are preferably selected from one of the following compounds: tetramethylene-l,4-diisocyanate, pentamethylene-l,5-diisocyanate, hexamethylene-l,6-diisocyanate, lysine diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane dimethylene isocyanate, diphenylmethane diisocyanate, toluene diisocyanate or p-phenyl diisocyanate. More preferably, they are selected from hexamethylene-l,6-diisocyanate or isophorone diisocyanate.
• the amount of phosphinoboron compound catalyst in accordance with formula (I) used in the present invention is 0.1-4 mol% of the amount of raw isocyanate monomer, preferably is 0.5-2 mol%, based on the mole amount of raw isocyanate monomers.
• the phosphinoboron compound catalysts of formula (I) in the present invention can be used solely or as a formulated solution, wherein the concentration of the formulated solution is 0.5-5 mol/L, preferably 2-4 mol/L; and the solvents used in formulating the solution are free of the active hydrogen; preferably, one, two or more of halogenated hydrocarbons, aromatic hydrocarbons or ethers; more preferably, one, two or more of dichloromethane, tetrahydrofuran, methylbenzene, dimethylbenzene or chlorobenzene.
• the temperature of the homopolymerization reaction of the raw isocyanate monomers is 20-120 °C, preferably, 50-100 °C.
• the homopolymerization reaction is terminated by using catalyst poisons.
• the catalyst poisons can be the known alkylating agents including dimethyl sulphate, methyl p-toluenesulphonate etc.; or phosphate esters including dimethyl phosphate, diethyl phosphate, di-n-butyl phosphate and so on.
• the mole ratio of the catalyst poison to the catalyst is 1 : 1 -2 : 1 ; preferably 1 :1-1.2:1.
• the phosphinoboron compound catalysts of formula (I) according to the present invention with a molecule of isocyanate can firstly form a transition state of four-membered ring structure having the structure of formula II , and further activate the carbon atom of NCO function group in the raw isocyanates, thereby rendering more liable to bond with another molecule of isocyanate, and can further result in a transition state as a six-membered ring structure of formula III.
• transition state of the six-membered ring Since the transition state of the six-membered ring is relatively stable, its ratio is higlier than every other intermediate transition state during the polymerization process of isocyanates (during the polymerization process, there are transition states of nine-membered rings for forming isocyanurate and iminooxadiazindione, i.e. formulae IV and V), it is the primary intermediate transition state. Accordingly, after the catalysts of the transition states of formulae III, IV and V are removed, the uretdione, isocyanurate and iminooxadiazindione are obtained, respectively, wherein the uretdione accounts for the main part.
• using the phosphinoboron compounds of the present invention as catalysts can effectively catalyze the homopolymerization reaction of raw isocyanate monomers to prepare polyisocyanates with a high uretdione group content.
• the process of the present invention achieves a higher conversion rate of raw isocyanates as well as a higher uretdione content in the product.
• lower chromaticity can be obtained via preparing the polyisocyanates by using phosphinoboron compounds of formula (I) according to the present invention as catalysts.
• the mole ratio of uretdione- containing polymers to the sum of other polymer components (i.e. the sum of polyisocyanates and polyiminooxadiazindione) in the resulted polyisocyanate homopolymers in the examples and the comparative examples is denoted as U/O.
• BYK LCS III is chosen as a colorimeter, with 50 mm sample cell, pure water (0 Hazen) is used as a reference.
• catalyst a was purchased from Sigma-Aldrich; catalyst b was prepared according to the process of the reference (Tetrahedron, 2009, 65, 6410-6415); catalyst c, d and f were prepared in accordance with the method described in the reference (J. Am. Chem. Soc, 1990, 112, 5244-5252); catalyst e was prepared according to the process of the reference (Tetrahedron, 2009, 65, 6410-6415).
• the catalysts in the comparative examples were selected from g and h with the following structures reported in the pate and CN 101450928, respectively:
• HDI hexamefhyIene-l,6-diisocyanate
• the process is similar to example 1, except using 0.12 mol catalyst g in catalyzing the homopolymerization reaction and 0.14 mol diethyl phosphate in terminating the reaction.
• the process is similar to example 1, except using 0.24 mol catalyst h in catalyzing the homopolymerization reaction and 0.24 mol diethyl phosphate in terminating the reaction.
• Chromati cities of the homopolymers prepared by the catalysts (examples 1-6) of the present invention are obviously lower than those of the comparative examples; furthermore, as the conversion rate increases from 20% to 60%, the increase of chromaticity in examples is obviously smaller than those in the comparative examples.
• IPDI isophorone diisocyanate
• the prepared HDI homopolymer When a combination of several catalysts of the present invention was applied, the prepared HDI homopolymer have a lower chromaticity; and the increase of chromaticity is obviously smaller when the conversion rate increases from 20% to 60%.

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• Polyurethanes Or Polyureas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2013
  • 2013-11-26 CN CN201310608843.5A patent/CN103613540B/zh active Active
• 2014
  • 2014-03-03 EP EP14866006.1A patent/EP3074380B1/en active Active
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