EP4093728A1 - Verfahren zur rückgewinnung von diisocyanaten aus destillationsrückständen - Google Patents
Verfahren zur rückgewinnung von diisocyanaten aus destillationsrückständenInfo
- Publication number
- EP4093728A1 EP4093728A1 EP21701445.5A EP21701445A EP4093728A1 EP 4093728 A1 EP4093728 A1 EP 4093728A1 EP 21701445 A EP21701445 A EP 21701445A EP 4093728 A1 EP4093728 A1 EP 4093728A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- diisocyanate
- solid
- weight
- polyisocyanate
- mbar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/18—Separation; Purification; Stabilisation; Use of additives
- C07C263/20—Separation; Purification
-
- 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
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
-
- 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
- C08G18/73—Polyisocyanates or polyisothiocyanates acyclic
-
- 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
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
- C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
-
- 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
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7678—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing condensed aromatic rings
Definitions
- the present invention relates to a process for separating a diisocyanate which is solid at room temperature from a distillation residue which is formed during a production process for the diisocyanate.
- the invention also relates to the diisocyanate which is solid at room temperature and which can be obtained by this process.
- the use of a thin-film evaporator and / or falling-film evaporator, a composition containing the diisocyanate which is solid at room temperature and a method for producing an elastomer from this composition and the elastomer itself are further objects of the invention.
- the viscosity of the residue must be reduced before recovery in order to be able to carry out a separation process at all. Heating non-liquid residues lowers their viscosity, but undesirable side reactions - e.g. oligomerization - of the diisocyanate to be isolated also occur.
- Another challenge in recovery is that in distillation processes the bottom effluent, i.e. the part that remains from the separated diisocyanate, can also have a high viscosity and can therefore only be removed from the separation apparatus with difficulty. In conventional recovery processes, this high viscosity is often based on oligomerizations of diisocyanate still present in the bottom effluent, which are caused by high temperatures.
- Naphthalene diisocyanate has found wide industrial application and can be produced from naphthalene diamine (NDA) using the known processes described at the beginning, such as phosgenation. Since monomeric naphthalene diisocyanate is a solid, The purification of the product is fundamentally a challenge compared to other isocyanates that are liquid at processing temperature, such as toluene diisocyanate (TDI). The difficulties are exacerbated by the physical properties of naphthalene diisocyanate, because it melts at 127 ° C and already at 130 ° C begins to sublime. The residue from the purification process for naphthalene diisocyanate still contains approx.
- No. 3,694,323 discloses a process for recovering an isocyanate from a residue with the aid of a further isocyanate which has a higher boiling point than the isocyanate to be purified and thus lowers the viscosity of the residue and enables cleaning.
- the publication also generally mentions naphthalene diisocyanate in a long list, but only discloses tolylene diisocyanate in the experimental section and does not contain any teaching on the particular difficulties involved in recovering a diisocyanate which is solid at room temperature.
- Another disadvantage of this process is that the process has a relatively high energy requirement, since temperatures between 190 ° C. and 250 ° C. are required in the examples for cleaning TDI.
- diisocyanates in particular diisocyanates which are solid at room temperature, such as naphthalene diisocyanate
- diisocyanates which are solid at room temperature, such as naphthalene diisocyanate
- the recovered diisocyanate should be as free as possible from foreign substances, such as additives from the recovery process.
- the object of the present invention to provide a process for the recovery of diisocyanates which are solid at room temperature, in particular naphthalene diisocyanate, from a distillation residue, with which at least an equal or even a higher proportion of the diisocyanate contained in the residue, in particular naphthalene diisocyanate, can be recovered, than with conventional methods.
- the method according to the invention should consume less energy and fewer additives than conventional methods.
- the recovered diisocyanate should be as free as possible of foreign substances, such as additives from the recovery process, so that it can be used as a starting material for further syntheses, for example polymer syntheses, without further purification processes.
- step (iii) Condensation of the gaseous product stream and obtaining a solid containing the diisocyanate which is solid at room temperature, the at least one polyisocyanate in step (i) having a residual monomer content of ⁇ 3.0% by weight, determined by gas chromatography using an internal standard according to DIN EN ISO 10283 : 2007-11.
- diisocyanates solid at room temperature can be recovered in good yield from a distillation residue if polyisocyanates made from diisocyanates other than diisocyanates solid at room temperature and having low residual monomer contents are added and the addition of bitumen is not necessary. Nevertheless, it is now possible to keep the mixture of the residue liquid throughout the entire distillation process. Furthermore, the recovered diisocyanate has a very low level of impurities.
- the process according to the invention enables an efficient production method, since it is possible to react to fluctuating workload in that the polyisocyanate added to the distillation residue can be varied accordingly.
- the references to “comprising”, “containing” etc. preferably mean “essentially consisting of” and very particularly preferably “consisting of”. The further embodiments mentioned in the patent claims and in the description can be combined as desired, unless the context clearly indicates the opposite.
- diisocyanates solid at room temperature means that the diisocyanates are in the solid state at 23 ° C and normal pressure, i.e. 1,000 mbar.
- naphthalene diisocyanate is understood as a generic term for the possible isomers or mixtures thereof. Examples of such isomers are 1,5-naphthalene diisocyanate or 1,8-naphthalene diisocyanate.
- At least one polyisocyanate based on one or more diisocyanates that are different from the diisocyanate which is solid at room temperature is understood to mean that this is not a monomeric diisocyanate and that no diisocyanates that are solid at room temperature are used in its production.
- Suitable thin-film evaporators are, for example, fixed-blade rotor thin-film evaporators or wiper flap thin-film evaporators or short-path evaporators.
- Suitable falling film evaporators are, for example, tube bundle down tube evaporators or helical tube evaporators.
- the at least one polyisocyanate in step (i) has a residual monomer content of ⁇ 1.5% by weight, preferably ⁇ 1.0% by weight and particularly preferably ⁇ 0.5% by weight, determined by gas chromatography with an internal standard in accordance with DIN EN ISO 10283: 2007-11.
- the yield and / or purity of recovered diisocyanate, which is solid at room temperature can be increased further.
- the residual monomer content of the at least one polyisocyanate is> 0.15% by weight. This has the further advantage that the efficiency of production systems can be further improved, since polyisocyanate which does not meet the desired specifications can still be used for recovery from the distillation residue.
- the distillation residue in step (i) preferably contains from 30 to 70% by weight of the diisocyanate which is solid at room temperature, more preferably 40 to 60% by weight, particularly preferably 45 to 55% by weight, based in each case on the distillation residue.
- the distillation residue is preferably low in solvent. This means that, based on its weight, it is preferably at most 20% by weight, more preferably at most 10% by weight and most preferably contains at most 5% by weight of one or more organic solvents.
- Organic solvent here means compounds that do not contain any isocyanate groups.
- Organic solvents are understood to mean, in particular, the compounds which are described further below in this application in the context of the phosgenation of amines.
- step (i) 85 to 75% by weight of the distillation residue with 15 to 25% by weight of the at least one polyisocyanate and preferably 85 to 80% by weight of the distillation residue with 15 to 20% by weight % of the at least one polyisocyanate mixed, based in each case on the sum of the masses of the distillation residue and of the at least one polyisocyanate.
- the diisocyanate which is solid at room temperature is 1,5-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, 1,4-phenylene diisocyanate, tetraline diisocyanate, o-tolidine diisocyanate, durene diisocyanate, benzidine diisocyanate and / or 1,4-anthrylene diisocyanate, more preferably 1, 5-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, 1,4-phenylene diisocyanate, tetraline diisocyanate and / or o-tolidine diisocyanate and particularly preferably 1,5-naphthalene diisocyanate and / or 1,8-naphthalene diisocyanate.
- the diisocyanates which are solid at room temperature can be prepared in any desired way, for example by reacting the corresponding diamines or their salts with phosgene. It is only important in each case that in the process used at least one distillation residue containing diisocyanates which are solid at room temperature remains, which can then be used in step (i) according to the invention.
- the production process of the diisocyanate is a phosgenation of a diamine, more preferably a liquid phase phosgenation of a diamine.
- diisocyanate preference is given to using a diamine which, apart from the isocyanate groups, has the structure of the diisocyanate, but in which the two amino groups are exchanged for isocyanate groups in the production process.
- An example is 1,5-naphthalene diamine as a corresponding diamine to 1,5-naphthalene diisocyanate. If the diisocyanate which is solid at room temperature is a mixture of isomers, a corresponding mixture of isomers of diamines is used.
- the continuous production of organic isocyanates by reacting primary organic amines with phosgene has been described many times and is carried out on an industrial scale.
- the diisocyanate which is solid at room temperature is particularly preferably produced from the corresponding diamine using phosgene according to the process known from WO 2014/044699 A1, which comprises the following steps: (A) Preparation of a suspension of the corresponding diamine in an inert solvent, the diamine being distributed in the solvent by means of a dynamic mixing unit,
- step (B) Phosgenation of the diamine suspended in the inert solvent to obtain the respective diisocyanate, the dynamic mixing unit in step (A) being selected from the group consisting of dispersion disks and rotor-stator systems, preferably rotor-stator systems, particularly preferred Colloid mills, tooth dispersing machines and three-roller mills. Tooth dispersing machines are very particularly preferred as dynamic mixing units.
- Suitable inert solvents are aromatic solvents, which can also be halogenated. Examples are toluene, monochlorobenzene, o-, m- or p-dichlorobenzene, trichlorobenzene, chlorotoluenes, chloroxylenes, chloroethylbenzene, chloronaphthalenes, chlorodiphenyls, xylenes, decahydronaphthalene, benzene or mixtures of the above solvents.
- suitable organic solvents are methylene chloride, perchlorethylene, hexane, diethyl isophthalate, tetrahydrofuran (THF), dioxane, trichlorofluoromethane, butyl acetate and dimethylformamide (DMF).
- THF tetrahydrofuran
- DMF dimethylformamide
- phosgene is used in excess. This means that more than one mole of phosgene is used per mole of amine groups.
- the molar ratio of phosgene to amine groups is accordingly from 1.01: 1 to 20: 1, preferably 1.1: 1 to 10: 1, particularly preferably 1.1: 1 to 5.0: 1 further phosgene or phosgene solution are fed to the reaction in order to maintain a sufficient excess of phosgene or to compensate for a loss of phosgene.
- reaction can be carried out continuously or batchwise.
- Reactors that can be used are stirred tanks, tubular reactors, spray towers or loop reactors. In principle, however, other designs that are not listed here as examples can also be used. It is preferred to work batchwise.
- the reaction can be carried out within the first reaction stage until conversion to the isocyanate is complete. However, it can also be advantageous or necessary to carry out a partial conversion, in particular of residues of amine hydrochloride, in a postreactor.
- the post-reactor can be conventional reactor designs with different degrees of backmixing, such as stirred tanks, loop reactors or tubular reactors. It can also be beneficial that To divide the reaction mixture into partial streams according to its particle size distribution and to feed it separately to one or more post-reactors. Known devices such as filters, cyclones or gravity separators can be used as designs for the separation.
- the substreams can be treated with appropriate mechanical methods for adjusting the particle size before or during the reaction, eg. B. by grinding.
- the unconverted phosgene is mostly recycled, optionally after purification, and reused for the phosgenation.
- the residue during the treatment in step (ii) has an average residence time of 1 to prison 15 minutes, preferably 1 to 10 minutes and particularly preferably 1 to 5 minutes in the at least one thin film evaporator and / or falling film evaporator, particularly preferably the residue has this residence time in a commercially available falling film evaporator made of glass, with an evaporator area of 0.1 m 2 (diameter 100 mm, length 300 mm).
- Step (ii) of the process is preferably carried out at a temperature of 130 ° C. to 180 ° C. and a pressure of 0.4 to 4 mbar, preferably from 140 ° C. to 170 ° C. and from 0.6 mbar to 2 mbar, particularly preferably from 150 ° C. to 160 ° C. and from 0.7 to 1.5 mbar.
- This has the advantage that the formation of by-products or the oligomerization of the diisocyanate and the mixed polyisocyanate can be largely suppressed during the distillation.
- the bottom discharge from step (ii) is preferably not a pesticide at the prevailing temperature at the outlet of the thin-film evaporator and / or Pall film evaporator.
- the bottom effluent is preferably discharged continuously from the distillation apparatus and then either recycled, e.g. by incineration for heat recovery, or discarded.
- the bottom discharge is particularly preferably liquid under the distillation conditions.
- a coolant is used in the distillation in step (iii), the coolant temperature preferably being below the melting point of the diisocyanate which is solid at room temperature.
- the coolant is used for rapid condensation of the product flow.
- the solid from step (iii) preferably contains at least 95% by weight of the diisocyanate which is solid at room temperature, more preferably at least 97% by weight, particularly preferably at least 99% by weight, based in each case on the solid.
- the proportion of solid diisocyanate in the solid is preferably determined by gas chromatographic methods.
- the reduced use of auxiliary materials such as bitumen in step (i) of the process minimizes the contamination of the monomeric diisocyanate which is solid at room temperature and is obtained from the residue.
- Polyisocyanates suitable for the process according to the invention in step (i) are any polyisocyanates produced by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates, for example those of the type mentioned below, which are preferably a uretdione, isocyanurate, allophanate, Biuret, iminooxadiazinedione and / or oxadiazinetrione structure, as described, for example, in J. Prakt. Chem.
- a polyisocyanate with a urethane structure can also be used which, according to known methods, by reacting simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates, for example those of the type mentioned below, with polyols with a molecular weight of 168 up to 4000 g / mol, preferably at least trimethylolpropane and / or diethylene glycol, can be produced, as well as any mixtures of such polyisocyanates.
- the polyisocyanates suitable for step (i) are thus oligomeric polyisocyanates which contain at least one structure selected from the group consisting of urethane, uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structures.
- Polyisocyanates which do not contain such a structure, i.e. are unmodified, are referred to in this application as monomeric poly- or diisocyanates.
- the actual modification reaction is generally followed by a further process step for separating off the unreacted excess monomeric diisocyanates.
- This separation of monomers is carried out by processes known per se, preferably by thin-film distillation in vacuo or by extraction with suitable solvents which are inert towards isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane or cyclohexane.
- the polyisocyanates more preferably have a monomeric diisocyanate content of ⁇ 3.0% by weight, preferably ⁇ 2.5% by weight, as defined above of ⁇ 2.0% by weight, even more preferably of ⁇ 1.5% by weight, particularly preferably of ⁇ 1.0% by weight and very particularly preferably of ⁇ 0.5% by weight, by gas chromatography internal standard determined according to DIN EN ISO 10283: 2007-11.
- the residual monomer content of the at least one polyisocyanate is> 0.15% by weight and ⁇ 3.0% by weight, preferably> 0.15% by weight and ⁇ 1.5% by weight, particularly preferably> 0.15% by weight and ⁇ 1.0% by weight and very particularly preferably> 0.15% by weight and ⁇ 0.5 wt%.
- the polyisocyanates mentioned above as being suitable, preferred, particularly preferred and very particularly preferred preferably contain isocyanurate structures and have an average NCO functionality of 2.3 to 5.0, preferably 2.5 to 4.5, and an isocyanate group content of 6.0 to 26.0% by weight, preferably from 8.0 to 25.0% by weight, particularly preferably 10.0 to 24.0% by weight.
- Suitable diisocyanates for the preparation of the polyisocyanates are any, in various ways, for example by phosgenation in the liquid or gas phase or by phosgene-free route, such as. B. by thermal urethane cleavage, accessible diisocyanates.
- Preferred diisocyanates are those of the molecular weight range 140 to 400 with aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, such as. B.
- 1,4-diisocyanatobutane 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2, 2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis (isocyanatomethyl) - cyclohexane, l-isocyanato-3,3,5-tri-methyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), m-xylylene diisocyanate (m-XDI), 4,4'-diisocyanatodicyclohexyl
- the at least one polyisocyanate in step (i) is particularly preferably a polyisocyanate obtainable by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates, preferably by modifying 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI ), 1,3- and 1,4-bis (isocyanatomethyl) -cyclohexane, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), m-xylylene diisocyanate (m-XDI), 4 , 4'-diisocyanatodicyclohexylmethane, bis- (isocyanatomethyl) -norbornane (NBDI), 2,4- and 2,6-diisocyanatotoluene (TD
- bitumen which was previously necessary for the recovery of diisocyanates which are solid at room temperature from distillation residues, is no longer necessary and the mixture can be kept liquid throughout the entire distillation process. If at all, less than 5% by weight of bitumen, preferably less than 2% by weight and particularly preferably 0% by weight of bitumen, based on the mass of the distillation residue, is present in step (i). Bitumen and its production are known to the person skilled in the art.
- the residue used in the process according to the invention contains> 0% by weight to ⁇ 4% by weight, preferably> 0.001% by weight to ⁇ 2% by weight and particularly preferably> 0.01% by weight % to ⁇ 1% by weight, based in each case on the total amount of the residue containing diisocyanates which are solid at room temperature, of monomeric diisocyanates whose boiling point is above the boiling point of the diisocyanate which is solid at room temperature and which differ from these.
- This is particularly advantageous since a high recovery yield can be achieved even without this addition and the purified diisocyanate, which is solid at room temperature, thus remains largely free of these impurities.
- The% by weight of monomeric diisocyanates whose boiling point is above the boiling point of the diisocyanate which is solid at room temperature is determined by gas chromatography using an FID detector, preferably using an Optima 5 column and the following parameters: Split rate: 8.31: 1 mF / min; Flow rate: 96.4 ml 7min pressure: 0.7 bar, carrier gas: helium, injection volume: 1 m ⁇ , inliner: straight split finer filled with Carbofritt, the area percent being set equal to the weight percent during the evaluation.
- a further embodiment of the invention relates to the use of a mixture containing 70 to 90% by weight of a distillation residue from a production process of a diisocyanate which is solid at room temperature and 10 to 30% by weight of at least one polyisocyanate based on one or more diisocyanates which are dated at room temperature solid diisocyanate are different, based in each case on the mixture, in a process for separating off the diisocyanate which is solid at room temperature by distillation using a thin-film evaporator and / or falling-film evaporator.
- the solid comprising the diisocyanate from step (iii) of the process which is solid at room temperature can preferably be used alone or in mixtures with a diisocyanate obtained directly from the first purification stage after the phosgenation reaction, all of which are familiar to the person skilled in the art Uses are supplied.
- the solid is used to produce high-performance elastomers such as Vulkollan®.
- Particularly preferred is the further processing of the solid with NCO-reactive compounds such as polyols to give polyurethanes, possibly via prepolymers as intermediate stages.
- a further embodiment of the invention relates to a composition
- a composition comprising a solid containing a diisocyanate which is solid at room temperature from step (iii) of a method according to any one of claims 1 to 9 and at least one NCO-reactive compound, preferably at least one polyester polyol.
- Further objects of the present invention are a process for producing an elastomer, in which at least one composition according to the invention is chemically reacted, optionally with heating, and the elastomer produced or produced by this process.
- elastomers are preferably polyurethanes, which are optionally obtained via prepolymers as intermediate stages.
- These polyurethanes preferably have densities of 200 kg / m 3 to 1400 kg / m 3 , particularly preferably from 600 kg / m 3 to 1400 kg / m 3 and very particularly preferably from 800 kg / m 3 to 1400 kg / m 3 .
- Cellular or solid cast elastomers are very particularly preferably produced, very particularly preferably cast elastomers based on polyester polyol.
- composition described above can preferably be conventional auxiliaries and additives, such as rheology improvers (for example ethylene carbonate, propylene carbonate, dibasic esters, 10 citric acid esters), stabilizers (for example Broensted and Lewis acids, such as hydrochloric acid, phosphoric acid, benzoyl chloride, organomineral acids such as Dibutyl phosphate, also adipic acid, malic acid, succinic acid, grape acid or citric acid), UV protection agents (for example 2,6-dibutyl-4-methylphenol), hydrolysis protection agents (for example sterically hindered carbodiimides), emulsifiers and catalysts (for example trialkylamines, 15 diazanicylamines , Tin dioctoate, dibutyltin dilaurate, N-alkylmorpholine, lead, zinc, tin, calcium, magnesium octoate, the corresponding naphthenates and p-nitrophenoIate and / or
- Preferred NCO-reactive compounds are polyether polyols, polyester polyols, polycarbonate polyols and polyether amines which have an average OH or NH functionality of have at least 1.5, as well as short-chain polyols and polyamines (chain extenders or crosslinkers), as they are well known from the prior art.
- These can be, for example, low molecular weight diols (eg 1,2-ethanediol, 1,3- or 1,2-propanediol, 1,4-butanediol), triols (eg glycerol, trimethylolpropane) and tetraolics (eg pentaerythritol), but also higher molecular ones Polyhydroxy compounds such as polyether polyols, polyester polyols, polycarbonate polyols, polysiloxane polyols, polyamines and polyether polyamines and polybutadiene polyols.
- diols eg 1,2-ethanediol, 1,3- or 1,2-propanediol, 1,4-butanediol
- triols eglycerol, trimethylolpropane
- tetraolics eg pentaerythritol
- Polyhydroxy compounds such as polyether polyol
- Polyether polyols can be obtained in a manner known per se by alkoxylating suitable starter molecules with base catalysis or using double metal cyanide compounds (DMC compounds).
- suitable starter molecules for the production of polyether polyols are, for example, simple, low molecular weight polyols, water, organic polyamines with at least two N-H bonds or any mixtures of such starter molecules.
- Preferred starter molecules for the production of polyether polyols by alkoxylation, in particular by the DMC process are in particular simple polyols such as ethylene glycol, propylene glycol-1,3- and butanediol-1,4, hexanediol-1,6, neopentyl glycol, 2-ethylhexanediol 1,3, glycerol, trimethylolpropane, pentaerythritol and low molecular weight, hydroxyl group-containing esters of such polyols 5 with dicarboxylic acids of the type mentioned below or low molecular weight ethoxylation or propoxylation products of such simple polyols or any mixtures of such modified or unmodified alcohols.
- Alkylene oxides suitable for the alkoxylation are, in particular, ethylene oxide and / or propylene oxide, which can be used in the alkoxylation in any order or as a mixture.
- Polyester polyols can be prepared in a known manner by polycondensation of low molecular weight polycarboxylic acid derivatives, such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetrahydrophthalic anhydride,
- low molecular weight polycarboxylic acid derivatives such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetrahydrophthalic anhydride
- polyester polyols can also be polycondensed to give polyester polyols.
- polyester polyols can, for example, by complete ring opening of epoxidized triglycerides of an at least partially olefinically unsaturated fatty acid-containing fat mixture with one or more alcohols with 1 to 12 carbon atoms and subsequent partial transesterification of the triglyceride derivatives to alkyl ester polyols with 1 to 12 carbon atoms in the alkyl radical.
- the NCO-reactive compound can contain short-chain polyols or polyamines as crosslinking components or chain extenders.
- Typical chain extenders are diethylenetoluenediamine (DETDA), 4,4'-methylenebis (2,6-diethyl) aniline (MDEA), 4,4'-methylenebis (2,6-diisopropyl) aniline (MDIPA), 4, 4'-methylenebis (3-chloro-2,6-diethyl) -aniline (MCDEA),
- Dimethylthiotoluenediamine (DMTDA, Ethacure® 300), N, N'-di (sec-butyl) -amino-biphenylmethane (DBMDA, Unilink® 4200) or N, N'-di-sec-butyl-p-phenylenediamine (Unilink® 4100 ), 3,3'-dichloro-4,4'-diaminodiphenylmethane (MBOCA), trimethylene glycol di-p-aminobenzoate (Polacure 740M).
- DMTDA Dimethylthiotoluenediamine
- DBMDA N'-di (sec-butyl) -amino-biphenylmethane
- MOCA 3,3'-dichloro-4,4'-diaminodiphenylmethane
- Polyacure 740M trimethylene glycol di-p-aminobenzoate
- 1,4-butanediol is very particularly preferably used for solid cast elastomers and water for cellular cast elastomers.
- NCO-terminated prepolymers Preference is given to using NCO-terminated prepolymers with an NCO content of 2 to 15% by weight, very particularly 2-10% by weight.
- the diisocyanate which is solid at room temperature, is preferably reacted with polyols of functionality 2 to 3, preferably 2, and an OH number of 28-112 mg KOH / g substance to form prepolymers.
- Ester-based polyols are preferably used.
- the NCO prepolymers produced in this way are either reacted further directly or stored as storage-stable prepolymers in, for example, barrels until they are finally used. 1,5-NDI-based prepolymers are preferably used.
- the production of the cast elastomers is advantageously carried out at an NCO / OH ratio of 0.7 to 1.30.
- the amount of the mixture introduced into the mold is usually such that the moldings obtained have the density already shown.
- the starting components are usually introduced into the mold at a temperature of 30 to 110 ° C.
- the degrees of compression are between 1.1 and 8, preferably between 2 and 6.
- the cellular elastomers are expediently produced using a low-pressure technique or, in particular, the reaction injection technique (RIM) in open, preferably closed molds. Reaction injection molding technology is well known to those skilled in the art.
- Additives such as castor oil or carbodiimides (e.g. Stabaxols from Rheinchemie as hydrolysis protection agents, 2,2 ', 6,6'-tetraisopropyldiphenylcarbodiimide is a well-known representative) can be added to both the polyol and the prepolymer.
- Water, emulsifiers, catalysts and / or auxiliaries and / or additives usually form the polyol component with the polyol.
- the molds For better demolding, it is customary to provide the molds with external release agents, for example compounds based on wax or silicone or aqueous soap solutions.
- external release agents for example compounds based on wax or silicone or aqueous soap solutions.
- the moldings removed from the mold are usually post-tempered for 1 to 48 hours at temperatures of 70 to 120.degree.
- emulsifier for example, sulfonated fatty acids and other well-known emulsifiers are used, such as.
- polysiloxanes can also be used.
- Salts of fatty acids with amines e.g., oleic diethylamine, stearic acidic diethanolamine, ricinic acidic diethanolamine, salts of sulfonic acids, e.g., alkali or ammonium salts of dodecylbenzene or dinaphthylmethane disulfonic acid are also preferred.
- amines e.g., oleic diethylamine, stearic acidic diethanolamine, ricinic acidic diethanolamine
- salts of sulfonic acids e.g., alkali or ammonium salts of dodecylbenzene or dinaphthylmethane disulfonic acid are also preferred.
- the sulfonated fatty acids can preferably be used as aqueous solutions, for example as a 50% solution.
- Typical well-known products are additives SV and SM from Rheinchemie and, as non-aqueous emulsifiers, additive WM from Rheinchemie.
- the process for producing the cellular PUR cast elastomers is carried out in the presence of water.
- the water acts both as a crosslinker with the formation of urea groups and as a blowing agent due to the reaction with isocyanate groups with the formation of carbon dioxide.
- the amounts of water which can expediently be used are 0.01 to 5% by weight, preferably 0.3 to 3.0% by weight, based on the weight of the polyol component.
- the water can be used completely or partially in the form of the aqueous solutions of the sulfonated fatty acids.
- the catalysts can be added individually or as a mixture with one another.
- organometallic compounds such as tin (II) salts of organic carboxylic acids, e.g. B. tin (II) dioctoate, tin (II) dilaurate, dibutyltin diacetate and dibutyltin dilaurate and tertiary amines such as tetramethylethylenediamine, N-methylmorpholine, diethylbenzylamine, triethylamine, dimethylcyclohexylamine, diazabethylpiperazine, niazabicycloiperoctane, Methyl-N '- (4-N-dimethylamino) butylpiperazine, N, N, N', N ", N" -
- organometallic compounds such as tin (II) salts of organic carboxylic acids, e.g. B. tin (II) di
- Suitable catalysts are: amidines, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tris- (dialkylamino-alkyl) -shexahydrotriazines, in particular tris- (N, N-dimethylamino-propyl) - s-hexahydrotriazine, Tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali hydroxides such as sodium hydroxide, and alkali alcoholates such as sodium methylate and potassium isopropylate, and alkali salts of long-chain fatty acids with 10 to 20 carbon atoms and optionally pendant OH groups.
- the catalysts are used in amounts of from 0.001 to 0.5% by weight, based on the isocyanate component.
- the elastomers according to the invention differ from the products known in the prior art based on monomeric diisocyanates that are solid at room temperature, preferably on 1,5-naphthalene diisocyanate, in that the process according to the invention also reduces the contamination of the monomeric products recovered from the residue Diisocyanate solid at room temperature is minimized with these auxiliaries.
- Such cellular PUR cast elastomers are used as damping elements in vehicle construction, for example in automobile construction, e.g. B. as additional springs, stop buffers, wishbone bearings, rear axle subframe bearings, stabilizer Fager, Fssensstreben- Fager, strut support bearings, shock absorber bearings, Fager for wishbones and as a spare wheel located on the rim, which, for example, in the event of a tire damage causes the vehicle to fall on the cellular elastomer drives and remains controllable.
- the solid cast elastomers can also be used as a coating for rollers, wheels and cylinders, doctor blades, screens or hydrocyclones.
- NDI Monomeric naphthalene diisocyanate
- Polyisocyanate 1 an aliphatic polyisocyanate based on pentamethylene diisocyanate (PDI) with an NCO content of 21.9% by weight and a viscosity of 9500 mPas at 23 ° C.
- PDI pentamethylene diisocyanate
- Polyisocyanate 2 an aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) with an NCO content of 11.0% by weight and a viscosity of 6000 mPas at 23 ° C.
- HDI hexamethylene diisocyanate
- Polyisocyanate 3 an aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) with an NCO content of 21.8% by weight and a viscosity of 3000 mPas at 23 ° C.
- HDI hexamethylene diisocyanate
- Polyisocyanate 4 an aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) with an NCO content of 23.0% by weight and a viscosity of 1200 mPas at 23 ° C.
- HDI hexamethylene diisocyanate
- Polyisocyanate 5 an aromatic polyisocyanate based on diphenylmethane diisocyanate (MDI) with an NCO content of 31.3% by weight and a viscosity of 680 mPas at 25 ° C.
- MDI diphenylmethane diisocyanate
- the residual monomer contents for the examples in Table 1 were set by adding the corresponding monomeric diisocyanate (PDI, HDI or MDI) and measured by gas chromatography using an internal standard in accordance with DIN EN ISO 10283: 2007-11.
- the purity of the NDI was determined by gas chromatography. The measurements were carried out on an HP 6890 from Hewlett Packard with FID detector and the HP Chemstation software using an Optima 5 column and the following parameters: Split rate: 8.31: 1 mL / min; Flow rate: 96.4 mL / min pressure: 0.7 bar, carrier gas: helium, injection volume: 1 m ⁇ , inliner: straight split liner filled with Carbofritt.
- the data in% by weight for the mixture relate to the mass of the entire mixture.
- the residual monomer content relates to the mass of the polyisocyanate used in each case.
- the respective mixture was fed to a vacuum distillation in a thin-film evaporator under the specified conditions, the monomeric 1,5-NDI being condensed as a solid.
- the bottom effluent which was still liquid at this temperature, consisted in each case of 1,5-NDI monomer, non-distillable components and polyisocyanate. All examples and comparative examples were carried out on a commercially available thin-film evaporator made of glass, with an evaporator area of 0.1 m 2 (diameter 100 mm, length 300 mm).
- a further advantage of the process according to the invention is that the bottom run-off is flowable, since further oligomerization reactions are largely suppressed by the lower temperatures compared with conventional processes and the shorter thermal load when carrying out the process according to the invention, which is a significant advantage for the continuous mode of operation.
- the diisocyanates obtained from the process according to the invention which are solid at room temperature are distinguished by a high degree of purity and can be used without restrictions for the production of elastomers.
Abstract
Description
Claims
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EP20153028 | 2020-01-22 | ||
PCT/EP2021/051094 WO2021148419A1 (de) | 2020-01-22 | 2021-01-20 | Verfahren zur rückgewinnung von diisocyanaten aus destillationsrückständen |
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Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1117066A (en) * | 1966-06-17 | 1968-06-12 | Ici Ltd | Distillation process for tolylene diisocyanate |
US3694323A (en) | 1968-08-05 | 1972-09-26 | Du Pont | Separation of distillable isocyanates from their phosgenation masses |
DE1954093C3 (de) | 1968-11-15 | 1978-12-21 | Mobay Chemical Corp., Pittsburgh, Pa. (V.St.A.) | Verfahren zur Herstellung von polymeren organischen Isocyanaten |
GB1353787A (en) * | 1971-09-27 | 1974-05-22 | Ici Ltd | Process for the purification of isocyanates |
DE2414413C3 (de) | 1974-03-26 | 1978-08-24 | Bayer Ag, 5090 Leverkusen | Verwendung von Lösungen von Polyisocyanaten mit Isocyanuratstruktur in Zweikomponenten-Polyurethan-Lacken |
DE2452532C3 (de) | 1974-11-06 | 1978-08-24 | Bayer Ag, 5090 Leverkusen | Verfahren zur Herstellung von Polyisocyanaten mit Isocyanurat-Struktur |
DE2641380C2 (de) | 1976-09-15 | 1989-11-23 | Bayer Ag, 5090 Leverkusen | Verfahren zur Herstellung von Polyisocyanaten mit Isocyanuratstruktur |
DE2932095A1 (de) * | 1979-08-08 | 1981-04-09 | Bayer Ag, 5090 Leverkusen | Verfahren zur herstellung von diisocyanatotoluol-gemischen mit einem erhoehten gehalt an 2,6-diisocyanatotoluol, sowie deren verwendung als aufbaukomponente bei der herstellung von polyurethanelastomeren |
DE3700209A1 (de) | 1987-01-07 | 1988-07-21 | Bayer Ag | Verfahren zur herstellung von polyisocyanaten mit biuretstruktur |
DE3811350A1 (de) | 1988-04-02 | 1989-10-19 | Bayer Ag | Verfahren zur herstellung von isocyanuratpolyisocyanaten, die nach diesem verfahren erhaltenen verbindungen und ihre verwendung |
DE3814167A1 (de) | 1988-04-27 | 1989-11-09 | Bayer Ag | Verfahren zur herstellung von isocyanuratgruppen aufweisenden polyisocyanaten und ihre verwendung |
DE3900053A1 (de) | 1989-01-03 | 1990-07-12 | Bayer Ag | Verfahren zur herstellung von uretdion- und isocyanuratgruppen aufweisenden polyisocyanaten, die nach diesem verfahren erhaeltlichen polyisocyanate und ihre verwendung in zweikomponenten-polyurethanlacken |
DE3928503A1 (de) | 1989-08-29 | 1991-03-07 | Bayer Ag | Verfahren zur herstellung von loesungen von isocyanuratgruppen aufweisenden polyisocyanaten in lackloesungsmitteln und ihre verwendung |
DE19611849A1 (de) | 1996-03-26 | 1997-10-02 | Bayer Ag | Neue Isocyanattrimerisate und Isocyanattrimerisatmischungen, deren Herstellung und Verwendung |
DE10260027A1 (de) | 2002-12-19 | 2004-07-08 | Basf Ag | Verfahren zur Abtrennung und Reinigung von Lösungsmittel von einem Reaktionsgemisch aus einer Isocyanatsynthese |
CN108147980B (zh) | 2012-09-24 | 2020-10-23 | 科思创德国股份有限公司 | 通过二胺悬浮体的光气化制备二异氰酸酯的方法 |
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- 2021-01-20 WO PCT/EP2021/051094 patent/WO2021148419A1/de unknown
- 2021-01-20 EP EP21701445.5A patent/EP4093728A1/de not_active Withdrawn
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