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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
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/26—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds
  • C08G65/2603—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen
  • C08G65/2606—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen containing hydroxyl groups
  • C08G65/2609—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds the other compounds containing oxygen containing hydroxyl groups containing aliphatic hydroxyl groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C47/00—Compounds having —CHO groups
  • C07C47/20—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms
  • C07C47/26—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms containing hydroxy groups
  • C07C47/263—Unsaturated compounds having —CHO groups bound to acyclic carbon atoms containing hydroxy groups acyclic
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C43/00—Ethers; Compounds having groups, groups or groups
  • C07C43/30—Compounds having groups
  • C07C43/315—Compounds having groups containing oxygen atoms singly bound to carbon atoms not being acetal carbon atoms
• • 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
  • C08G18/54—Polycondensates of aldehydes
  • C08G18/546—Oxyalkylated polycondensates of aldehydes
• • 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
  • C08G18/56—Polyacetals
• • 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
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/30—Chemical modification by after-treatment
  • C08G2/34—Chemical modification by after-treatment by etherification
• • 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
  • C08G2650/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G2650/28—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule characterised by the polymer type
  • C08G2650/34—Oligomeric, e.g. cyclic oligomeric

Definitions

• the invention relates to new starting compounds for the production of polyurethanes and a process for their preparation.
• Polyurethanes and their production have long been known and have been described many times in the literature. They are usually produced by reacting polyisocyanates with compounds having at least two hydrogen atoms reactive with isocyanate groups.
• Polyols are mostly used as compounds with at least two hydrogen atoms reactive with isocyanate groups.
• the greatest technical importance here are the polyether alcohols and the polyester alcohols.
• Polyester alcohols are usually produced by reacting at least difunctional alcohols with at least difunctional carboxylic acids.
• the polyether alcohols are generally obtained by adding alkylene oxides to OH- or NH-functional starter compounds.
• the price of the usual polyols is determined by the starter compounds used and the alkylene oxides used, especially propylene oxide and ethylene oxide.
• a much cheaper starting compound for the production of polyols would be formaldehyde.
• formaldehyde reacts with itself to form oligomers that have terminal hydroxyl groups.
• this reaction usually leads to a mixture of oligomers and polymers with different chain lengths, which are in equilibrium with formaldehyde.
• compounds with such a broad molecular weight distribution are unusable for the production of polyurethanes.
• Another disadvantage of these connections is their lack of stability. The oligomers and polymers are split back after a short time.
• DD 247223 describes a process for the preparation of polyether alcohols in which a mixture of formaldehyde condensates, known as formose, and other compounds having active hydrogen atoms is reacted with alkylene oxides. In this process too, the formose has a broad molecular weight distribution.
• EP 1 063221 describes a method for preparing formaldehyde oligomers of the general formula (I) with a narrow molecular weight distribution, starting from formaldehyde. The implementation follows the general equation
• the resulting oligomer mixture of 2-9 formaldehyde units like polyoxymethylene, is unstable. In addition to higher molecular compounds (paraformaldehyde), water and monomolecular hydrated formaldehyde are formed within 2 hours.
• the invention accordingly relates to starting compounds for the production of polyurethanes, hereinafter also referred to as polyurethane raw materials, which can be prepared by reacting oligomers of formaldehyde containing hydroxyl groups.
• the invention further relates to a process for the production of polyurethane raw materials by reacting the hydroxyl groups of oligomers of formaldehyde.
• the compounds of the general formula (I) can be prepared by known processes. It is thus possible to produce the oligomers by known polymerization of trioxane, a cyclic reaction product of the formaldehyde. This process is known from the literature. It is preferably used for the production of polyoxymethylene (POM) and is described, for example, in the Römpp Chemie Lexikon. However, this process is not preferred for the production of the polyurethane raw materials according to the invention, since high-molecular reaction products are preferably formed.
• POM polyoxymethylene
• the oligomers are prepared by the process described in EP 1 063221, the subsequent reaction of the oligomers with aniline described in this document being dispensed with.
• the oligomers of formaldehyde are produced by removing certain fractions from a solution in which there is an equilibrium between formaldehyde and its oligomers. This separation is preferably carried out by distillation, mostly by means of a film evaporator, in particular by means of a thin-film evaporator. Suitable operating conditions for the film evaporator are generally a temperature between 10 and 230 ° C, preferably between 10 and 150 ° C, at an absolute pressure between 0.5 mbar and 2 bar. Temperatures between 20 and 100 ° C. at normal pressure are preferred for the separation of an aqueous formaldehyde solution.
• fractions of oligomers of formaldehyde separated in this way usually have a very narrow molecular weight distribution. As stated above, they are stable in storage for a certain time and should be processed further during this time in order to avoid a change in their composition.
• the terminal hydroxyl groups are reacted with alkylene oxides to form polyether alcohols.
• the reaction is usually carried out as in the known production of polyether alcohols using the usual alcoholic starter substances.
• the oligomers of formaldehyde are reacted with the alkylene oxides in the presence of catalysts.
• basic compounds such as amines, basic metal oxides and metal hydroxides, in particular potassium hydroxide, can be used as catalysts.
• Multimetal cyanide compounds also referred to as DMC catalysts
• DMC catalysts are preferably used as catalysts. Such compounds have long been known and are described for example in EP 654302 or in EP 862947.
• the advantage of using DMC catalysts is, on the one hand, that they can remain in the product after the reaction, and, on the other hand, that, unlike basic catalysts, they do not promote the cleavage of the oligomers.
• the compounds known and customary for this purpose can be used as alkylene oxides.
• the greatest technical importance has ethylene oxide and propylene oxide, which can be used individually or in any mixtures with one another.
• the two alkylene oxides can be dosed together in a so-called statistic or in succession in so-called alkylene oxide blocks.
• the type and amount of the metered alkylene oxides depends in particular on the use of the polyether alcohols.
• the polyether alcohols have short chains for use in rigid foams.
• the hydroxyl number of such polyether alcohols is usually in the range between 300 to 600, in particular between 400 and 500 mg KOH / g.
• Propylene oxide is preferably used as the alkylene oxide.
• Long-chain polyether alcohols are mostly used for use in flexible foams.
• the hydroxyl number of these polyether alcohols is usually in the range between 30 and 120 mg KOH / g, preferably in the range between 30 and 60 mg KOH / g.
• Mixtures of ethylene oxide and propylene oxide are mostly used as alkylene oxides.
• a pure ethylene oxide block is added to the end of the polyether chain.
• propylene oxide or statistical mixtures of propylene oxide and ethylene oxide are preferably used as alkylene oxide.
• the ratio of the two alkylene oxides to one another in the mixture is changed in a statistical mixture of ethylene oxide and propylene oxide during the metering, as described in WO 01/44347.
• the oligomers of formaldehyde can be reacted with the alkylene oxides alone or as a mixture with other H-functional starter substances.
• At least two-functional alcohols such as glycerol, trimethylolpropane, ethylene glycol, propylene glycol and their higher homologs, are preferably used as additional starting substances.
• the reaction of the starting substance with the alkylene oxides is generally carried out at the pressures customary for this in the range between 0.1 and 1.0 MPa and the customary temperatures in the range between 80 and 140 ° C.
• the metering of the alkylene oxides is usually followed by a post-reaction phase for the complete reaction of the alkylene oxides.
• catalyst in particular amine catalyst, is again added to the reaction mixture at the beginning of the post-reaction phase, preferably immediately after metering in of the alkylene oxides has ended.
• the polyether alcohols are usually subjected to a short distillation treatment to remove volatile impurities.
• the polyether alcohol can then be filtered to remove any solid contaminants.
• the catalyst is removed after the addition of the alkylene oxides. This can be done by neutralization with acids or by using adsorbents. The salts or adsorbents are then removed by filtration.
• the reaction of the oligomers of formaldehyde with the alkylene oxides can also be carried out continuously, in particular using DMC catalysts.
• the separated oligomer mixture and the alkylene oxide and the catalyst are continuously fed to a reactor and the polyether alcohol formed is continuously removed from the reactor.
• Such continuous processes are described for example in DD 203235 and WO 98/03571.
• the continuous reaction can be carried out, for example, in tubular reactors, stirred tanks or loop reactors.
• the continuous production of the polyether alcohols by reaction of the oligomers with alkylene oxides can be directly connected to the separation of the oligomers which is also carried out continuously
• the polyether alcohols obtained in this way can be easily converted into polyurethanes using isocyanates by customary processes.
• the polyether alcohols according to the invention can be used alone or preferably in a mixture with other compounds with additional alcohols, in particular short-chain polyfunctional alcohols, polyether and / or polyester alcohols, preferably polyether alcohols.
• the short-chain alcohols used are usually two- or more-functional alcohols with a molecular weight in the range between 62 and 400 g / mol, such as ethylene glycol, propylene glycol and their higher homologues or glycerol.
• the polyether alcohols and polyester alcohols which can be used are the compounds which are customary and known for this purpose. They usually have a molecular weight Mn of more than 400 g / mol, preferably in the range between 400 and 15000 g / mol.
• These polyols are prepared by customary and known processes, in the case of polyester alcohols by reaction of polyfunctional alcohols with polyfunctional carboxylic acids, in the case of polyether alcohols by addition of alkylene oxides onto H-functional starter substances. Depending on the nature of the desired polyurethanes, the reaction is optionally carried out in the presence of catalysts, blowing agents and customary auxiliaries and / or additives.
• the oligomers of formaldehyde are reacted with isocyanates to form prepolymers after their separation from the reaction mixture.
• the terminal hydroxyl groups of the oligomers of the general formula (I) separated off as described above are reacted with isocyanates. Since the oligomers are only stable in storage for a limited time, here too the reaction must take place immediately after the oligomers have been separated off if a product with a narrow molar mass distribution is to be obtained.
• the reaction of all hydroxyl groups of the oligomers completely suppresses their cleavage.
• the prepolymers are stable on storage and can be processed like prepolymers from other polyols commonly used in polyurethane chemistry.
• the reaction of the hydroxyl group-containing oligomers with the isocyanates is carried out according to the customary method of preparation for prepolymers containing isocyanate groups.
• the oligomer is reacted with at least such an amount of isocyanate that is sufficient for complete conversion of the hydroxyl groups of the oligomers.
• the reaction can be carried out in the presence of conventional urethane formation catalysts.
• the isocyanate compound is usually initially introduced, optionally in the presence of a catalyst, at a temperature of 40 to 100 ° C., preferably 50 to 80 ° C.
• the oligomer mixture is metered in with stirring, and the reaction mixture is then optionally allowed to after-react until complete conversion, usually up to 2 hours, at 60 to 140 ° C., preferably at 80 to 100 ° C.
• the NCO content of the prepolymers depends on the molar mass of the oligomers, the excess of isocyanate used, the reaction time, the residence time, the reaction temperature and the catalysts used.
• the NCO content of the prepolymers is usually in the range between 10 to 30% by weight, preferably 15 to 25% by weight.
• the oligomers of formaldehyde can be reacted with the isocyanates individually or as a mixture with other compounds with at least two hydrogen atoms reactive with isocyanate groups.
• the components which can be reacted with the oligomers of formaldehyde with isocyanates to form prepolymers are, in particular, alcohols.
• different alcohols can be used in an amount of 0 to 90% by weight, preferably 0 to 60% by weight, based in each case on the sum of the oligomers of formaldehyde and the other compounds with at least two hydrogen atoms reactive with isocyanate groups be used.
• short-chain polyfunctional alcohols polyether and / or polyester alcohols, preferably polyether alcohols, are used as additional alcohols.
• the short-chain alcohols used are usually two- or more-functional alcohols with a molecular weight in the range between 62 and 400 g / mol, such as ethylene glycol, propylene glycol and their higher homologues or glycerol.
• Polyether alcohols and polyester alcohols which can be used are those which are customary for this purpose and are described in more detail above. It is also possible to react the polyether alcohols which have been prepared by adding alkylene oxides to oligomers of the general formula (I) together with the oligomers of formaldehyde with isocyanates.
• isocyanates with two or more isocyanate groups in the molecule are used as isocyanates for the process according to the invention.
• Both aliphatic isocyanates such as hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), or preferably aromatic isocyanates, such as tolylene diisocyanate (TDI), “ diphenylmethane diisocyanate (MDI) or mixtures of diphenylmethane diisocyanate and polymethylene polyphenylene MDI and polyisocyanates (P)
• TDI tolylene diisocyanate
• MDI diphenylmethane diisocyanate
• P polymethylene polyphenylene MDI and polyisocyanates
• isocyanates which have been modified by the incorporation of uretdione, isocyanurate, allophanate, uretonimine and other groups, and these compounds are often also referred to as modified isocyanates
• the prepolymers produced in this way can be processed to give polyurethanes with compounds which have at least one, preferably at least two, hydrogen atoms reactive with isocyanate groups in the molecule.
• the prepolymers can be processed into rigid foams, flexible foams, adhesives, coatings or elastomers.
• a formalin solution with a formaldehyde content of 37% by weight was evaporated to a theoretical formaldehyde content of 73% by weight using a thin-layer evaporator apparatus at a wall temperature of 80 ° C. and 120 mbar.
• the solution was stored at 80 ° C and processed within an hour. 961 g of this solution were mixed with 38.4 g of dimethylcyclohexylamine in a pilot plant autoclave and 1010 g of propylene oxide were metered in at 100 ° C. within 6 hours.
• the reaction mixture was then left to react for 2 hours at the same temperature. Then volatile constituents were removed in vacuo.
• the remaining liquid reaction product had a hydroxyl number of 685 mg KOH / g and a water content of 0.011% by weight.
• a GPC investigation showed oligomeric products with a molecular weight in the range of 100-500 g / mol.
• Investigations by gas chromatography and coupled mass spectroscopy (GC-MS) showed that adducts had formed from 2 molecules of propylene oxide and 2 molecules of formaldehyde.
• a formalin solution with a formaldehyde content of 37% by weight was evaporated to a theoretical formaldehyde content of 73% by weight using a thin-layer evaporator apparatus at a wall temperature of 80 ° C. and 120 mbar.
• the solution was stored at 80 ° C and processed within an hour. 1110 g of this solution was mixed with 70 g of potassium hydroxide in a pilot plant autoclave and 1600 g of propylene oxide were metered in over 9 hours.
• the liquid reaction product had a hydroxyl number of 868 mg KOH / g and a water content of 0.014% by weight.
• An investigation using gel permeation chromatography showed oligomeric products with a molar mass in the range of 100-500 g / mol.
• GC-MS showed that adducts had formed from 2 molecules of propylene oxide and 2 molecules of formaldehyde.

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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)
• General Chemical & Material Sciences (AREA)
• Polyurethanes Or Polyureas (AREA)
• Polyoxymethylene Polymers And Polymers With Carbon-To-Carbon Bonds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2003
  • 2003-04-28 DE DE10319242A patent/DE10319242A1/de not_active Withdrawn
• 2004
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  • 2004-04-16 JP JP2006505160A patent/JP2006524648A/ja active Pending
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  • 2004-04-16 EP EP04727865A patent/EP1620383A1/de not_active Withdrawn
  • 2004-04-16 CN CNB2004800111013A patent/CN100349844C/zh not_active Expired - Fee Related
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