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
  • C08G18/06—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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/14336—Coating a portion of the article, e.g. the edge of the article
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/1418—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being deformed or preformed, e.g. by the injection pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C67/00—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00
  • B29C67/24—Shaping techniques not covered by groups B29C39/00 - B29C65/00, B29C70/00 or B29C73/00 characterised by the choice of material
  • B29C67/246—Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM]
• • 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
  • C08G18/09—Processes comprising oligomerisation of isocyanates or isothiocyanates involving reaction of a part of the isocyanate or isothiocyanate groups with each other in the reaction mixture
  • C08G18/092—Processes comprising oligomerisation of isocyanates or isothiocyanates involving reaction of a part of the isocyanate or isothiocyanate groups with each other in the reaction mixture oligomerisation to isocyanurate groups
• • 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
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
  • C08G18/1816—Catalysts containing secondary or tertiary amines or salts thereof having carbocyclic groups
• • 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
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
  • C08G18/20—Heterocyclic amines; Salts thereof
  • C08G18/2009—Heterocyclic amines; Salts thereof containing one heterocyclic ring
  • C08G18/2018—Heterocyclic amines; Salts thereof containing one heterocyclic ring having one nitrogen atom in the ring
• • 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
  • C08G18/28—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
  • C08G18/44—Polycarbonates
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
  • B29C37/0025—Applying surface layers, e.g. coatings, decorative layers, printed layers, to articles during shaping, e.g. in-mould printing
  • B29C37/0028—In-mould coating, e.g. by introducing the coating material into the mould after forming the article
  • B29C2037/0035—In-mould coating, e.g. by introducing the coating material into the mould after forming the article the coating being applied as liquid, gel, paste or the like
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0053—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor combined with a final operation, e.g. shaping
  • B29C2045/0079—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor combined with a final operation, e.g. shaping applying a coating or covering
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
  • B29C45/1418—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being deformed or preformed, e.g. by the injection pressure
  • B29C2045/14286—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being deformed or preformed, e.g. by the injection pressure means for heating the insert
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
  • B29C37/0025—Applying surface layers, e.g. coatings, decorative layers, printed layers, to articles during shaping, e.g. in-mould printing
  • B29C37/0028—In-mould coating, e.g. by introducing the coating material into the mould after forming the article
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0001—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor characterised by the choice of material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/0053—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor combined with a final operation, e.g. shaping
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• • 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
  • C08G2120/00—Compositions for reaction injection moulding processes

Definitions

• the present invention relates to the use of polyisocyanate compositions and trimerization catalysts for the production of coatings by reaction injection molding, the coatings obtained through this use and correspondingly coated workpieces.
• WO 2016/170058 or WO 2016/170059.
• WO 2018/073303 describes the production of coatings from reaction mixtures with a large excess of isocyanate groups over isocyanate-reactive groups.
• a well-known process for building up coatings is reaction injection molding.
• a workpiece to be coated is introduced into a mold which is dimensioned such that a cavity is present between the inside of the mold and the surface of the workpiece, the width of which corresponds to the layer thickness of the coating to be produced.
• this method offers advantages in terms of production technology, since the injection of the coating agent into a mold can be carried out more easily and quickly than building up a coating by spraying, dipping or brushing. This is especially true when the workpiece to be coated has a more complex three-dimensional shape.
• Reaction injection molding can particularly advantageously be combined with the production of a plastic component to be coated by producing the plastic component in a first mold and then transferring it directly to a further mold in which the coating is applied. It is also possible to change the geometry of the first mold, for example by moving part of the mold, in such a way that a cavity for the coating agent is created between the workpiece and the inside of the mold.
• polyurethane coatings are produced by injecting a mixture of a polyol, a polyisocyanate and a urethanization catalyst into the gap.
• a polyol a polyol
• a polyisocyanate a polyisocyanate
• a urethanization catalyst In order to achieve sufficiently short cycle times, systems are required that cure quickly. This requires, especially when using aliphatic isocyanate and hydroxyl compounds, the use of catalysts of high activity in very large amounts. These large amounts of highly active catalysts can reduce the service life of the coating because they remain in the product and often also catalyze hydrolysis or other degradation processes that destroy the coating in the long term.
• the other method is based on the formation of polyureas.
• the required high reaction rates can be achieved quite easily due to the high reactivity of isocyanates towards amines.
• the coatings produced in this way are less scratch-resistant than comparable polyurethane coatings and are therefore unsuitable for a number of applications.
• the present invention relates to the use of a reaction mixture with a molar ratio of isocyanate groups to isocyanate-reactive groups of at least 3: 1 for coating workpieces by reaction injection molding, the reaction mixture a) at least one polyisocyanate composition A, and b) at least one Contains trimerization catalyst B and at least 30 mol% of the free isocyanate groups present in the reaction mixture are converted to isocyanurate groups.
• the reaction mixture according to the invention contains the constituents defined above in a mixing ratio which enables the polyisocyanate A to cure to form a polyisocyanurate plastic.
• the components are mixed and are reactive with the temperature increase defined below in this application.
• the molar ratio of isocyanate groups to isocyanate-reactive groups in the reaction mixture is at least 3: 1, preferably at least 5: 1.
• isocyanate-reactive groups in the present application includes epoxy, hydroxyl, carboxyl, amino and Understood thiol groups. The study on which the present invention is based has shown that reaction mixtures with a stoichiometric ratio of isocyanate groups to isocyanate-reactive groups of at least 3: 1 have noticeably better performance properties than reaction mixtures which do not achieve this value.
• the isocyanurate groups that are formed are formed. Therefore, in a preferred embodiment of the present invention, at least 40 mol%, preferably at least 50 mol% and most preferably at least 60 mol% of the free isocyanate groups present in the reaction mixture are converted to isocyanurate groups.
• solvents can be added to adjust the viscosity.
• a solvent is characterized in that it has no isocyanate-reactive groups.
• a solvent can escape from the coating, but can also remain in the film and act as a plasticizer there.
• Suitable solvents are the solvents known to those skilled in the art for diluting polyisocyanates, preferably aliphatic acetates, aromatic hydrocarbons, esters, ethers and polyethers, glycol ethers and water. Water, butyl acetate, ethyl acetate, 1-methoxy-2-propyl acetate, butanone, solvent naphtha, xylene and toluene are particularly preferred.
• the reaction mixture according to the invention therefore contains a maximum of 10% by weight, preferably a maximum of 5% by weight and more preferably a maximum of 2% by weight of organic solvent which contains neither isocyanate groups nor isocyanate-reactive groups.
• the viscosity of the reaction mixture in the application is preferably at most 10,000 mPas, preferably at most 5,000 mPas, even more preferably at most 2,500 mPas and most preferably 1,000 mPas at the injection temperature determined in accordance with DIN EN ISO 3219 / B (edition of October 1, 1994) at a Shear rate of 100 s 1 .
• Typical injection temperatures are 20-140 ° C, preferably 30-100 ° C and particularly preferably 40-90 ° C, and very particularly preferably 50-60 ° C. If the reaction mixture contains oligomeric polyisocyanates as defined below in this application, its viscosity can be above the aforementioned values. In these cases, the viscosity can be reduced by using monomeric polyisocyanates as reactive thinners.
• polyisocyanate composition A denotes the entirety of all compounds contained in the reaction mixture which contain at least one isocyanate group per molecule Has proportion of compounds with an average of at least two isocyanate groups per molecule in order to cause crosslinking of the reaction mixture. As long as this criterion is met, the presence of compounds with an average of one isocyanate group per molecule is harmless.
• the polyisocyanate A can thus consist of a single polyisocyanate. But it can also be a mixture of several different polyisocyanates. In the context of the embodiments defined below, the polyisocyanate A can also contain admixtures of isocyanates with an average functionality of less than two.
• polyurethanes e.g. polyurethanes, polyureas and polyisocyanurates
• low molecular weight compounds e.g. those with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure
• polyisocyanates e.g. polyurethanes, polyureas and polyisocyanurates
• low molecular weight compounds e.g. those with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure
• polyisocyanates refers to monomeric and / or oligomeric polyisocyanates. To understand many aspects of the invention, however, it is important to distinguish between monomeric diisocyanates and oligomeric polyisocyanates.
• oligomeric polyisocyanates are used in this application, then polyisocyanates are meant which are built up from at least two monomeric diisocyanate molecules, ie they are compounds which represent or contain a reaction product of at least two monomeric diisocyanate molecules.
• oligomeric polyisocyanates from monomeric diisocyanates is also referred to here as modification of monomeric diisocyanates.
• modification means the reaction of monomeric diisocyanates, optionally other isocyanate-reactive molecules, to give oligomeric polyisocyanates with a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure.
• flexamethylene 1,6-diisocyanate is a "monomeric diisocyanate” because it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules: HDI
• reaction products of at least two HDI molecules which still have at least two isocyanate groups are "oligomeric polyisocyanates" within the meaning of the invention.
• oligomeric polyisocyanates are, based on the monomeric HDI, for example the HDI isocyanurate and the HDI biuret , each made up of three monomeric HDI molecules:
• the proportion by weight of isocyanate groups based on the total amount of polyisocyanate composition A is preferably at least 5% by weight. More preferably at least 10% by weight.
• the polyisocyanate composition A can consist essentially of monomeric polyisocyanates or essentially of oligomeric polyisocyanates. However, it can also contain oligomeric and monomeric polyisocyanates in any mixing ratio.
• the polyisocyanate composition A used as starting material is low in monomers (i.e. low in monomeric diisocyanates) and already contains oligomeric polyisocyanates.
• the terms “low in monomer” and “low in monomeric diisocyanates” are used synonymously in relation to the polyisocyanate composition A.
• the polyisocyanate composition A has a proportion of monomeric diisocyanates of not more than 20% by weight, in particular not more than 15% by weight or not more than 10% by weight, based in each case on the weight of the polyisocyanate composition A.
• the polyisocyanate composition preferably has A has a monomeric diisocyanate content of not more than 5% by weight, preferably not more than 2.0% by weight, particularly preferably not more than 1.0% by weight, based in each case on the weight of the polyisocyanate composition A.
• Particularly simple and safe processing is ensured if the polyisocyanate composition A is essentially free from monomeric diisocyanates. Essentially free here means that the content of monomeric diisocyanates is at most 0.5% by weight, particularly preferably even below 0.10%, based on the weight of the polyisocyanate composition A.
• the polyisocyanate composition A consists entirely or at least 80, 85, 90, 95, 98, 99 or 99.5% by weight, based in each case on the weight of the polyisocyanate composition A, of oligomeric polyisocyanates.
• a content of oligomeric polyisocyanates of at least 99% by weight is preferred here.
• This oligomeric polyisocyanate content relates to polyisocyanate composition A as provided. That is, the oligomeric polyisocyanates are not formed as an intermediate product during the process according to the invention, but are already present in the polyisocyanate composition A used as starting material at the beginning of the reaction.
• Polyisocyanate compositions which are low in monomer or essentially free from monomeric isocyanates can be obtained by carrying out at least one further process step in each case to separate off the unreacted excess monomeric diisocyanates after the actual modification reaction.
• This separation of monomers can be carried out in a particularly practical manner by methods known per se, preferably by thin-film distillation in a high vacuum 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 polyisocyanate A is obtained by modifying monomeric diisocyanates with subsequent removal of unreacted monomers.
• a low-monomer polyisocyanate composition A contains a monomeric foreign diisocyanate.
• “monomeric foreign diisocyanate” means that it differs from the monomeric diisocyanates that were used to prepare the oligomeric polyisocyanates contained in polyisocyanate composition A.
• the isocyanate A has a proportion of monomeric external diisocyanate of at most 50% by weight, in particular at most 30% by weight or at most 15% by weight, based in each case on the weight of the polyisocyanate composition A.
• the polyisocyanate composition A preferably has a content of monomeric foreign diisocyanate of not more than 10% by weight, preferably not more than 2.0% by weight, particularly preferably not more than 1.0% by weight, based in each case on the weight of the polyisocyanate composition A.
• the polyisocyanate composition A contains monomeric isocyanates with an isocyanate functionality greater than two, i.e. with more than two isocyanate groups per molecule.
• the addition of monomeric isocyanates with an isocyanate functionality greater than two has proven to be advantageous in order to influence the network density of the coating.
• Particularly practical results are obtained when the polyisocyanate composition A contains a proportion of monomeric isocyanates with an isocyanate functionality greater than two in the polyisocyanate composition A of at most 20% by weight, in particular at most 15% by weight or at most 10% by weight on the weight of the polyisocyanate composition A.
• the polyisocyanate composition A preferably has a content of monomeric monoisocyanates or monomeric isocyanates with an isocyanate functionality greater than two of at most 5% by weight, preferably at most 2.0% by weight, particularly preferably at most 1.0% by weight, in each case based on the weight of the polyisocyanate composition A on.
• no monomeric monoisocyanate or monomeric isocyanate with an isocyanate functionality greater than two is also used in the trimerization reaction according to the invention.
• Monomeric isocyanates with an isocyanate functionality> 2 are, for example, triisocyanatononane and PMDI.
• the oligomeric polyisocyanates can in particular have uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure.
• the oligomeric polyisocyanates have at least one of the following oligomeric structure types or mixtures thereof:
• a polyisocyanate composition A is used whose isocyanurate structural content is at least 50 mol%, preferably at least 60 mol% %, more preferably at least 70 mol%, even more preferably at least 80 mol%, even more preferably at least 90 mol% and particularly preferably at least 95 mol% based on the sum of the oligomeric structures present from the group consisting of uretdione -, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure in the polyisocyanate composition A.
• a polyisocyanate composition A is used in the process according to the invention which, in addition to the isocyanurate structure, contains at least one further oligomeric polyisocyanate with uretdione, biuret, allophanate, iminooxadiazinedione and oxadiazinetrione structure and mixtures thereof.
• the proportions of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure in polyisocyanate composition A can be determined, for example, by NMR spectroscopy. 13C-NMR spectroscopy, preferably proton-decoupled, can preferably be used here, since the oligomeric structures mentioned provide characteristic signals.
• an oligomeric polyisocyanate composition A to be used in the process according to the invention preferably has an (average) NCO functionality of 2.0 to 5 , 0, preferably from 2.3 to 4.5.
• the polyisocyanate composition A to be used according to the invention has an isocyanate group content of 8.0 to 28.0% by weight, preferably from 14.0 to 25.0% by weight, based in each case on the weight of the Polyisocyanate composition A, has.
• the polyisocyanate composition A is defined in that it contains oligomeric polyisocyanates which are particularly preferred from monomeric diisocyanates regardless of the type of modification reaction used while maintaining a degree of oligomerization of 5 to 45%, preferably 10 to 40% 15 to 30%.
• the "degree of oligomerization” is to be understood as the percentage of isocyanate groups originally present in the starting mixture which is to be understood during the Manufacturing process with the formation of urethane, uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures is consumed.
• Suitable polyisocyanates for producing the polyisocyanate composition A to be used according to the invention and the monomeric and / or oligomeric polyisocyanates contained therein are any polyisocyanates accessible in various ways, for example by phosgenation in the liquid or gas phase or by phosgene-free route, such as, for example, by thermal urethane cleavage. Particularly good results are obtained when the polyisocyanates are monomeric diisocyanates.
• Preferred monomeric diisocyanates are those which have a molecular weight in the range from 140 to 400 g / mol, 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, 1,4-diisocyanato-3,3, 5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane
• IPDI Isophorone diisocyanate
• H12MDI 2,4'- and 4,4'-diisocyanatodicyclohexylmethane
• 1,3- and 1,4-bis isocyanatomethyl cyclohexane, bis-
• Suitable monomeric monoisocyanates which can optionally be used in polyisocyanate composition A are, for example, n-butyl isocyanate, n-amyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, cetyl isocyanate, stearyl isocyanate, cyclohexyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate or any mixtures of such monoisocyanates.
• polyisocyanate composition A contains at most 30% by weight, in particular at most 20% by weight, at most 15% by weight, at most 10% by weight, at most 5% by weight or at most 1% by weight %, in each case based on the weight of the polyisocyanate composition A, of aromatic polyisocyanates.
• aromatic polyisocyanate means a polyisocyanate which has at least one aromatically bound isocyanate group.
• Aromatically bound isocyanate groups are understood to mean isocyanate groups which are bound to an aromatic hydrocarbon radical.
• the polyisocyanate composition A consists of at least 70, 80, 85, 90, 95, 98 or 99% by weight, based in each case on the weight of the polyisocyanate composition A, of polyisocyanates which are exclusively aliphatically and / or cycloaliphatically bound Have isocyanate groups. Practical tests have shown that particularly good results can be achieved with polyisocyanate compositions A in which the isocyanates contained therein exclusively have aliphatically and / or cycloaliphatically bound isocyanate groups.
• Aliphatically or cycloaliphatically bound isocyanate groups are understood to mean isocyanate groups which are bound to an aliphatic or cycloaliphatic hydrocarbon radical.
• a polyisocyanate A is used which consists of or contains one or more oligomeric polyisocyanates, the one or more oligomeric polyisocyanates exclusively having aliphatically and / or cycloaliphatically bound isocyanate groups.
• a polyisocyanate composition A which consists of or contains one or more oligomeric polyisocyanates, the one or more oligomeric polyisocyanates based on 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), isophorone diisocyanate (IPDI) or 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or mixtures thereof.
• BDI 1,4-diisocyanatobutane
• PDI 1,5-diisocyanatopentane
• HDI 1,6-diisocyanatohexane
• IPDI isophorone diisocyanate
• H12MDI 4,4'-diisocyanatodicyclohexylmethane
• the polyisocyanates contained in the polyisocyanate composition A are blocked. “Blocking” means that the isocyanate groups of a polyisocyanate have reacted with another compound, the blocking agent, so that the blocked isocyanate groups are no longer those for free Isocyanate groups show typical reactivity. Only thermal activation of the blocked isocyanate leads to an increase in the reactivity towards isocyanate-reactive groups or free isocyanate groups, so that polymerization can take place. Suitable blocking agents are generally known to the person skilled in the art.
• At least one compound is selected from the group consisting of alcohols, phenols, pyridinoies, thiophenols, quinolinoies, mercaptopyridines, quinolinoies, amides, imides, imidazoles, imidazolines, lactams, oximes, pyrazoles, triazoles, malonic esters, acetoacetic esters, acetyl ketones and cyclopentyl ketones -Alkyl esters, used as blocking agents.
• the blocking takes place with a compound selected from the group consisting of mercaptopyridines, quinolinoies, amides, imides, imidazoles, imidazolines, lactams, oximes, pyrazoles, triazoles, malonic esters, acetoacetic esters, acetyl ketones and cyclopentanone-2-alkyl esters. At least one cyclopentanone-2-alkyl ester is very particularly preferably used.
• lactams, amides and imides are selected from the group consisting of N-methylacetamide, acetanilide, g-butyrolactam, x-enantholactam, d-valerolactam, laurolactam, e-caprolactam, 5-methyl-2-piperidone, 3,6-dialkyl 2,5-piperazidinone or phthalimide.
• a particularly preferred lactam is e-caprolactam.
• Preferred oximes are selected from the group consisting of 2-butanone oxime, 3-methyl-2-butanone oxime, 3,3-dimethyl-2-butanone oxime, 4-methyl-2-pentanone oxime, 5-methyl-2-hexanone oxime, 2-heptanone oxime , 4,6-dimethyl-2-heptanone oxime, 3-ethyl-2-nonoxime, 2,4-dimethyl-3-pentanone oxime, 2,6-dimethyl-4-heptanone oxime, formal doxime, acetophenone oxime, dieth glyoxime, pentanone oxime, flexanon oxime, cyclohexanone oxime , 2,2,6,6-tetramethylcyclohexanone oxime, 2, 2,4,4-
• Tetramethylcyclobutane-l, 3-dione-l-oxime and flydroxamic acid is 2-butanone oxime.
• Suitable phenols, quinolines and pyridinoies include the esters of 2-hydroxybenzoic acid and 4-hydroxybenzoic acid, such as methyl 2-hydroxybenzoate, ethyl 2-hydroxybenzoate, 2-ethylhexyl-2-hydroxybenzoate, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate -hydroxybenzoate or 2-ethylhexyl-4-hydroxybenzoate, 2- [(dimethylamino) methyl] phenol, 2 - [(dimethylamino) methyl] -4-nonylphenol, phenol, 2,3,5-trimethylphenol, 2,3,6- Trimethylphenol, 2,4,6-trimethylphenol, o-cresol, m-cresol, p-cresol, 2-tert-butylphenol, 4-tert-butylphenol, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxy
• Preferred phenols are selected from the group consisting of phenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,4,6-trimethylphenol, o-cresol, m-cresol, p-cresol, 2-tert -Butylphenol and 4-tert-butylphenol.
• Suitable alcohols include, for example, linear and branched aliphatic alcohols such as isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, 2,2-dimethyl-1-propanol, n-hexanol, 2-ethylhexanol, 1-octanol or 2-0ctanol, cyclohexanol, furfuryl alcohol, monoethers of ethylene glycol, such as 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, N-, diethylene glycol monobutyl ether or ethanol, 2-ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, N-, 2-ethylene glycol monobutyl ether, N-, 2-ethylene glycol monobutyl
• Suitable imidazoles, imidazolines, pyrazoles and triazoles are, for example, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-ethyl-4-methylimidazole, 2,4-dimethylimidazoline, 4-methylimidazoline, 2-phenylimidazoline, 4-methyl-2- phenylimidazoline, 3-methylpyrazole, 3,5-dimethylpyrazole, 1,2,4-triazole or benzotriazole.
• Preferred pyrazole is 3,5-dimethylpyrazole.
• Malonic acid esters, acetoacetic acid esters and acetyl ketona include, for example, dimethyl malonate, diethyl malonate, diisopropyl malonate, tert-butyl methyl malonate, di-tert-butyl malonate, isopropylidene malonate, methyl acetoacetate, ethyl aetoacetate, isoprpylacetoacetate, 2, 4 oxy acetyl acetonate, isoprpylacetoacetate, 2, 4 oxy acetyl acetonate, acetyl acetonate, isopropyl acetonate, 2, 4, anyl methoxyacetonate, isoprpylacetoacetate, acetylacetone acetone, isoprpylacetoacetate, 2, 4, oxy methylacetone, acetone, acetone, acetone, acetone, acetone
• Preferred secondary amines are selected from the group consisting of diisopropylamine, dibutylamine, di-tert-butylamine, N-methyl-tert-butylamine, tert-butylbenzylamine, 2,2,4-trimethylhexamethyleneamine, 2,2,5-trimethylhexamethyleneamine, N- Methylhexylamine, N-isopropylcyclohexylamine, dicyclohexylamine, bis (3,3,5-trimethylcyclohexyl) -amine, 3-tert-butylaminomethylpropionate, piperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 4- (dimethylamino) -2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-piperidon-bis (2,2,6,6-
• Tetramethylpieridinyl) amine N-methylaniline, diphenylamine or N-phenylnaphthalene.
• Diisopropylamine, tetramethylpiperidine and N-methyl-tert-butylamine, tert-butylbenzylamine, n-dibutylamine and 3-tert-butylaminomethylpropionate are particularly preferred.
• Cyclopentanone-2-alkyl ester cyclopentanone-2-methyl ester, cyclopentanone-2-ethyl ester, cyclopentanone-2-propyl ester, cyclopentanone-2-butyl ester and cyclopentanone-2-pentylyl ester are preferred. Cyclopentanone-2-methyl ester is particularly preferred. According to the invention, it is possible to use a mixture of two, three or more of the aforementioned compounds as blocking agents.
• the majority of the isocyanate groups present in the polyisocyanate composition A are blocked. Most preferably at least 90% by weight, even more preferably at least 95% by weight and most preferably 98% by weight of the isocyanate groups present in the polyisocyanate composition A are blocked.
• the polyisocyanate composition A very particularly preferably does not contain any detectable free isocyanate groups. Free isocyanate groups can be determined by means of IR spectroscopy. The NCO band is observed at 2700 cm 1.
• Silane modifications are used in coatings, for example to increase the hardness and / or the scratch resistance of the coating. If silane-modified isocyanates are used, both silane-functional groups and isocyanate groups are present in one molecule.
• the crosslinking of the silane groups with one another can be catalyzed, but it can also take place through post-curing, e.g. via air humidity.
• formulations with silane-functional isocyanates are designed in such a way that, after the first curing step, a coating is already present which can be demolded and which then reaches its final hardness through postcrosslinking.
• the polyisocyanate composition A contains at least one silane-functional polyisocyanate, particularly preferably at least one silane-functional oligomeric polyisocyanate. These are compounds containing at least one silane group and at least one isocyanate group.
• Silane-functional oligomeric polyisocyanates are usually obtained by oligomerizing simple aliphatic, cycloaliphatic, araliphatic and / or aromatic, monomeric diisocyanates, as described above as starting diisocyanates for the preparation of the oligomeric polyisocyanates, in a mixture with silicon-modified diisocyanates and / or isocyanatoalkysilanes or by partial conversion obtained oligomeric polyisocyanates with isocyanate-reactive silicon-containing compounds.
• partial reaction with silicon-containing compounds or “silicon-modified” are used interchangeably in the context of the invention and mean in particular that 1 to 99.9 mol%, preferably 5 to 80 mol%, particularly preferably 10 to 50 mol%, very particularly preferably 15 to 40 mol%, of the isocyanate groups originally present in the oligomeric polyisocyanate or in the diisocyanate have been reacted with silicon-containing compounds.
• those produced by partial reaction of oligomeric polyisocyanates with silicon-containing compounds oligomeric, silane-functional polyisocyanates have an isocyanate content of 99.0 to 0.1 mol%, preferably 95 to 20 mol%, particularly preferably 90 to 50 mol%, very particularly preferably 85 to 60 mol%. based on the isocyanate groups originally present in the oligomeric polyisocyanates.
• oligomeric, silane-functional polyisocyanates are, for example, the polyisocyanates containing allophanate and silane groups, which are described in EP-A 2014692 and EP-A 2 305 691 and obtainable by reacting hydroxy urethanes or hydroxyamides containing silane groups with excess amounts of monomeric diisocyanates.
• thioallophanates described in WO 2015/189164 in polyisocyanate composition A is also preferred, since, with a high content of silane groups, they also have a high average isocyanate functionality.
• These are compounds that are characterized by the general formula (I), in which R 1 , R 2 and R 3 stand for identical or different radicals and each represent a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical with up to 18 carbon atoms, which optionally has up to 3 May contain heteroatoms from the series oxygen, sulfur, nitrogen,
• X is a linear or branched organic radical with at least 2 carbon atoms
• Y is a linear or branched, aliphatic or cycloaliphatic, an araliphatic or aromatic radical with up to 18 carbon atoms
• n is an integer from 1 to 20.
• silane-functional polyisocyanates obtained by reacting the polyisocyanates mentioned earlier in this application as constituents of the polyisocyanate composition with silane-functional compounds, preferably silane-functional amines, aspartates, amides and thiols, is also preferred.
• silane-functional amines are selected from the group consisting of compounds according to formula (II), (III) and (IV).
• R 5 , R 6 and R 7 stand for identical or different radicals and each represent a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical with up to 18 carbon atoms, which optionally has up to 3 May contain heteroatoms from the series oxygen, sulfur, nitrogen,
• X stands for a linear or branched organic radical having at least 2 carbon atoms, which can optionally contain up to 2 imino groups (-NH-), and
• R 8 represents hydrogen, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or an optionally substituted aromatic or araliphatic radical with up to 18 carbon atoms or a radical of the formula stands in which R 5 , R 6 , R 7 and X have the meaning given above.
• Suitable aminosilanes of the general formula (II) are, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylethyldiethoxysilane, 3-aminopropyldimethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminoprop
• R 9 and R 10 are independently saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or aromatic organic radicals having 1 to 18 carbon atoms, which are substituted or unsubstituted and / or have heteroatoms in the chain.
• R 5 , R s and R 7 have the meaning given for formula (II)
• R 11 represents a saturated linear or branched, aliphatic or cycloaliphatic organic radical having 1 to 8 carbon atoms.
• aminosilanes of the general formula (IV) are the known silane-functional alkylamides, such as can be obtained, for example, by the processes disclosed in US Pat.
• the trimerization catalyst B contains at least one catalyst which effects the trimerization of isocyanate groups to give isocyanurates and / or to give iminooxadiazinediones.
• Suitable catalysts for the process according to the invention are, for example, simple tertiary amines, such as, for example, triethylamine, tributylamine, N, N-dimethylaniline, N-ethylpiperidine or N, N'-dimethylpiperazine.
• Suitable catalysts are also the tertiary hydroxyalkylamines described in GB 2221465, such as triethanolamine, N-methyl-diethanolamine, dimethylethanolamine, N-isopropyldiethanolamine and 1- (2-hydroxyethyl) pyrrolidine, or those known from GB 2 222 161, from mixtures tertiary bicyclic amines, such as DBU, with simple low molecular weight aliphatic alcohols existing catalyst systems.
• a large number of different metal compounds are also suitable as trimerization catalysts for the process according to the invention.
• the octoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or their mixtures with acetates of lithium, sodium, potassium, calcium or barium, which are described as catalysts in DE-A 3240613, are suitable, the sodium and potassium salts known from DE-A 3 219608 of linear or branched alkanecarboxylic acids with up to 10 carbon atoms, such as propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid and undecylic acid, which from EP-A 0 100 129 known alkali or alkaline earth metal salts of aliphatic, cycloaliphatic or aromatic mono- and polycarboxylic acids having 2 to 20 carbon atoms, such as sodium or potassium benzoate, which are disclosed in GB-PS 1,391,066 and GB-PS 1,386,399 known
• trimerization catalysts suitable for the process according to the invention are, for example, the quaternary ammonium hydroxides known from DE-A 1667309, EP-A 0013880 and EP-A 0047452, such as tetraethylammonium hydroxide, trimethylbenzylammonium hydroxide, N, N-dimethyl-N-dodecyl-N- (2 -hydroxyethyl) ammonium hydroxide, N- (2-hydroxyethyl) -N, N-dimethylN- (2,2'-dihydroxymethylbutyl) ammonium hydroxide and 1- (2-hydroxyethyl) -1, 4-diazabicyclo- [2.2.2 ] Octane hydroxide (monoadduct of ethylene oxide and water with 1,4-diazabicyclo [2.2.2] octane), the quaternary hydroxyalkylammonium hydroxides known from EP-A 37 65 or EP-A 10 589
• Tetraalkylammonium alkyl carbonates which are obtainable by reacting tertiary amines with dialkyl carbonates, or betaine-structured quaternary ammonio alkyl carbonates, the quaternary ammonium hydrogen carbonates known from WO 1999/023128, such as choline bicarbonate, the esters known from EP 0 102482 from tertiary amines and alkylating esters Quaternary ammonium salts obtainable from acids of phosphorus, such as reaction products of triethylamine, DABCO or N-methylmorpholine with dimethyl methanephosphonate, or the tetrasubstituted ammonium salts of lactams known from WO 2013/167404, such as trioctylammonium caprolactamate or dodecylcaprolactamate or dodecyltrimethyl ester.
• trimerization catalysts B suitable according to the invention can be found, for example, in J. H. Saunders and K. C. Frisch, Polyurethanes Chemistry and Technology, pp. 94 ff (1962) and the literature cited there.
• Carboxylates and phenates with metal or ammonium ions as counterions are particularly preferred.
• Suitable carboxylates are the anions of all aliphatic or cycloaliphatic carboxylic acids, preferably those with mono- or polycarboxylic acids having 1 to 20 carbon atoms.
• Suitable metal ions are derived from alkali or alkaline earth metals, manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium, tin, titanium, hafnium or lead.
• Preferred alkali metals are lithium, sodium and potassium, particularly preferably sodium and potassium.
• Preferred alkaline earth metals are magnesium, calcium, strontium and barium.
• the octoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or mixtures thereof with acetates of lithium, sodium, potassium, calcium are very particularly preferred or barium.
• trimerization catalyst B is poorly or not soluble in the polyisocyanate composition A, its effect can be made possible or enhanced by adding a solubilizer.
• Trimerization catalysts B based on alkali and alkaline earth oxides, hydroxides, carbonates or alcoholates preferably contain a polyether. This is particularly preferred when the catalyst contains metal ions.
• Preferred polyethers are selected from the group consisting of crown ethers, diethylene glycol, polyethylene and polypropylene glycols.
• a trimerization catalyst B which contains, as polyether, a polyethylene glycol or a crown ether, particularly preferably 18-crown-6 or 15-crown-5.
• the trimerization catalyst B preferably contains a polyethylene glycol with a number average molecular weight of 100 to 1000 g / mol, preferably 300 g / mol to 500 g / mol and in particular 350 g / mol to 450 g / mol.
• trimerization catalysts described in EP 3 337 836 and WO2015 / 124504 are particularly well suited for the use according to the invention.
• the reaction mixture contains at least one isocyanate-reactive compound C.
• An “isocyanate-reactive compound” is a compound which carries at least one isocyanate-reactive group as defined above in this application suggest that the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups according to the claims is maintained in the reaction mixture.
• Isocyanate-reactive compounds C are preferably used as solvents for the trimerization catalyst B and / or as a flexibilizing component.
• a "flexibilizing component" lowers the Tg of a coating compared to a coating obtained from the same reaction mixture without adding the flexibilizing component.
• monohydric or polyhydric alcohols, amino alcohols, amines and thiols are suitable as isocyanate-reactive compound C.
• the aforementioned compounds preferably have an average functionality of at least 2 isocyanate-reactive groups per molecule.
• Preferred amines are organic di- or polyamines, preferably selected from the group consisting of 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, the isomer mixture of 2 , 2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, 4,4-diaminodicyclohexamethane, hydrazine hydrate, Dimethylethylenediamine, polyethers modified with amino end groups and compounds according to formula (V) are used.
• the aforementioned compounds are preferably used as a flexibilizing component.
• X stands for an n-valent radical which is inert towards isocyanate groups, as it is by
• R 1 and R 2 for identical or different organic radicals with 1 to 18 carbon atoms and n for an integer> 1.
• Amines which contain at least one amino group and at least one hydroxyl group are likewise preferred.
• Such compounds are preferably selected from the group consisting of diethanolamine, 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexyl-aminopropane, 3-amino-1-methylaminobutane,
• Alkanolamines such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol and neopentanolamine.
• the aforementioned compounds are preferably used as a flexibilizing component.
• all known monomeric and polymeric polyols can be used individually or as a mixture as a flexibilizing component.
• These are in particular the usual polyester polyols, polyether polyols, polyacrylate polyols and polycarbonate polyols known from polyurethane chemistry.
• Suitable polyester polyols are preferably those having an average molecular weight, which can be calculated from functionality and hydroxyl number, of 200 g / mol to 3000 g / mol, preferably of 250 to 2500, with a hydroxyl group content of 1 to 21% by weight, preferably 2 to 18% by weight, as they are in a manner known per se by reacting polyhydric alcohols with insufficient amounts of polybasic carboxylic acids Let carboxylic acid anhydrides, corresponding polycarboxylic acid esters of lower alcohols or lactones be produced.
• Suitable polyether polyols are preferably those with an average molecular weight, which can be calculated from functionality and hydroxyl number, of 200 g / mol to 6000 g / mol, preferably 250 g / mol to 4000 g / mol with a hydroxyl group content of 0.6 to 34 wt. %, preferably 1 to 27% by weight, as can be obtained in a manner known per se by alkoxylation of suitable starter molecules.
• Any polyhydric alcohols for example those in the molecular weight range 62 g / mol to 400 g / mol, can be used to produce these polyether polyols.
• Suitable polyacrylate polyols are, for example, those having an average molecular weight, which can be calculated from functionality and hydroxyl number or can be determined by gel permeation chromatography (GPC), of 800 to 50,000, preferably 1000 to 20,000, with a hydroxyl group content of 0.1 to 12% by weight, preferably 1 to 10, how they can be produced in a manner known per se by copolymerization of olefinically unsaturated monomers containing hydroxyl groups with olefinic monomers free of hydroxyl groups.
• GPC gel permeation chromatography
• Suitable monomers for producing the polyacrylate polyols are vinyl or vinylidene monomers such as styrene, ⁇ -methylstyrene, o- or p-chlorostyrene, o-, m- or p-methylstyrene, p-tert-butylstyrene, acrylic acid, acrylonitrile , Methacrylonitrile, acrylic and methacrylic acid esters of alcohols with up to 18 carbon atoms, such as. B.
• B vinyl acetate or vinyl propionate, hydroxyalkyl esters of acrylic acid or methacrylic acid with 2 to 5 carbon atoms in the hydroxyalkyl radical, such as.
• the compounds mentioned above as solvents for the trimerization catalyst B are also suitable for use as flexibilizing components. These connections can thus fulfill a double function.
• Particularly preferred isocyanate-reactive compounds are those compounds which do not contribute to a substantial increase in the viscosity of the reaction mixture as defined above, but allow the reaction mixture to be processed at the injection temperature within the viscosity limits defined above.
• the reaction mixture preferably contains at least one additive D selected from the group consisting of stabilizers also against UV light, antioxidants, water scavengers, leveling agents, rheology additives, slip additives, defoamers, wetting and dispersing agents, adhesion promoters, corrosion inhibitors, flame retardants, nanoparticles, fillers also in the form of inorganic or organic fibers, dyes and pigments.
• additive D selected from the group consisting of stabilizers also against UV light, antioxidants, water scavengers, leveling agents, rheology additives, slip additives, defoamers, wetting and dispersing agents, adhesion promoters, corrosion inhibitors, flame retardants, nanoparticles, fillers also in the form of inorganic or organic fibers, dyes and pigments.
• Suitable UV stabilizers can preferably be selected from the group consisting of piperidine derivatives, such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-1,2,2,6,6-pentamethylpiperidine, bis- ( 2,2,6,6-tetra-methyl-4-piperidyl) sebacate, bis (1,2,2,6, 6-pentamethyl-l-4-piperidinyl) sebacate, bis- (2,2,6 , 6-tetramethyl-4-piperidyl) suberate, bis (2,2,6,6-tetramethyl-4-piperidyl) dodecanedioate; Benzophenone derivatives, such as, for example, 2,4-dihydroxy-, 2-hydroxy-4-methoxy-, 2-hydroxy-4-octoxy-, 2-hydroxy-4-dodecyloxy- or 2,2'-dihydroxy-4-dodecyloxy-benzophenone ; Benzotriazole derivatives such as 2-
• UV stabilizer derivatives such as, for example, 4-methoxy-benzylidene-malonic acid dimethyl ester, 4-methoxy-benzylidene-malonic acid diethyl ester, 4-butoxy-benzylidene-malonic acid dimethyl ester.
• These preferred UV stabilizers can be used either individually or in any combination with one another.
• one or more of the exemplified UV stabilizers of the coating compositions according to the invention are preferably used in amounts of 0.001 to 3.0% by weight, particularly preferably 0.01 to 2% by weight, calculated as the total amount of UV stabilizers used, based on the total amount of polyisocyanate component A added.
• Combinations of UV absorbers and radical scavengers are preferred, in particular those radical scavengers which belong to the group of sterically hindered light stabilizers (“HALS”).
• HALS sterically hindered light stabilizers
• Suitable antioxidants are preferably sterically hindered phenols, which can preferably be selected from the group consisting of 2,6-di-tert-butyl-4-methylphenol (ionol), pentaerythritol tetrakis (3- (3,5-di-tert butyl-4-hydroxyphenyl) propionate), octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol bis (3-tert-butyl-4-hydroxy -5-methylphenyl) propionate, 2,2'-thio-bis (4-methyl-6-tert-butylphenol) and 2,2'-thiodiethyl-bis [3- (3,5-di-tert-butyl-4 hydroxyphenyl) propionate]. If required, these can be used individually or in any combination with one another.
• antioxidants are preferably used in amounts of 0.01 to 3.0% by weight, particularly preferably 0.02 to 2.0% by weight, calculated as the total amount of antioxidants used based on the total amount of polyol component A.
• water scavengers for example orthoformic acid esters, such as. B. triethyl orthoformate, or vinylsilanes, such as. B. vinyltrimethoxysilane.
• orthoformic acid esters such as. B. triethyl orthoformate
• vinylsilanes such as. B. vinyltrimethoxysilane
• the reaction mixtures according to the invention can optionally contain suitable leveling agents, for example organically modified siloxanes, such as. B. polyether-modified siloxanes, polyacrylates and / or fluorosurfactants contain.
• suitable leveling agents for example organically modified siloxanes, such as. B. polyether-modified siloxanes, polyacrylates and / or fluorosurfactants contain.
• These leveling agents come, if at all, in amounts from 0.01% by weight to 3% by weight, preferably from 0.01% by weight to 2% by weight, particularly preferably from 0.05 to 1% by weight , 5% by weight, based on the total amount of the reaction mixture used.
• the reaction mixture can contain rheology additives, for example colloidal silicas, very finely divided bentonites, microcrystalline polyethylene waxes, polyamide dispersions and / or crystalline ureas.
• rheology additives for example colloidal silicas, very finely divided bentonites, microcrystalline polyethylene waxes, polyamide dispersions and / or crystalline ureas.
• the slip additives, defoamers, fillers and / or pigments also optionally contained in the coating compositions according to the invention as further auxiliaries and additives are the Known to those skilled in the art and, if at all, are used in the amounts customary in paint technology. A detailed overview of such suitable auxiliaries and additives can be found, for example, in Bodo Müller, "Additive Kompakt", Vincentz Network GmbH & Co KG (2009).
• the components of the reaction mixture according to the invention are mixed immediately before the cavity is filled in the Reaction Injection Molding (RIM) process using automated metering and mixing devices. It is preferred that the reaction mixture is provided in two or three components in suitable storage vessels and is dosed automatically from the storage vessels.
• the individual components are preferably temperature-controlled differently or all in the same way in such a way that the desired injection temperature of the mixture can be easily achieved. Depending on the desired injection method, the components can already be made available in the storage vessels under increased pressure.
• polyisocyanate mixture A and trimerization catalyst B are then preferably provided in different storage vessels.
• the additive component D and, if present, the optional isocyanate-reactive compound C are preferably also added to component B.
• the reaction mixture only arises while the components are being injected into the shaping tool.
• polyisocyanate mixture A and trimerization catalyst B are preferably provided in different storage vessels.
• At least part of the additive component D and optionally part of the optional isocyanate-reactive compound C is provided as a third component in further storage vessels.
• the third component can then be present in different forms, for example colors and / or effects, in different storage vessels, which can be processed with a 3K RIM system known per se in a rapid change in color and / or effect.
• Parts of components D and C can also be added to the component which contains the trimerization catalyst B.
• the third component contains a coloring and / or effect pigment paste which contains at least one polyester or polyether polyol (mentioned under C) and at least one dispersing aid (named under D).
• the production of the individual components takes place according to the usual methods of coating technology for two- or multi-component polyurethane paints, for example Mixing in stirring vessels or, if solids such as pigments are present, in dispersing systems such as dissolvers or grinding units such as bead mills.
• the workpiece which serves as a carrier for the coating to be built up, is introduced into a shaping tool which at least partially encloses the workpiece. It is preferred that the shaping tool can be heated, because in this way the curing of the reaction mixture can be brought about by simply heating the tool.
• the inside of the shaping tool which faces the workpiece and comes into contact with the reaction mixture, can be structured in order to create a structure on the surface of the coating to be built up.
• the workpiece contains at least one material selected from the group consisting of plastics, composites such as fiber-reinforced plastics, electronic components, wood, natural stone and metal. It preferably consists of at least 90% by weight of one or more of the aforementioned materials.
• Preferred plastics are selected from the group consisting of ABS, AMMA, ASA, CA, CAB, COC, EP, UF, CF, MF, MP, PF, PAN, PA, PBS, PC, PE, PE-HD, PE-LD , PE-LLD, PE-UHMW, PPS, PET, PEEK, PLA, PMMA, PP, PS, PPS, SB, PUR, PVC, SAN, PBT, PPE, POM, PP / EDP, UP (abbreviations according to DIN EN ISO 1043-1: 2016), polyoxazolidinones, thermoplastic polyurethane, melamine-phenol-formaldehyde, and mixtures thereof.
• the workpiece to be coated consists of at least 90% by weight of a thermoplastic polymer.
• the workpiece can optionally be pretreated. Examples of pretreated workpieces are workpieces provided with adhesion promoters, metallized workpieces, printed workpieces, workpieces coated with decorative foils, labeled workpieces, stained, colored and / or wooden workpieces treated with primers.
• a workpiece to be coated does not necessarily consist of a single component.
• This further component is preferably selected from the group consisting of sensors, lighting elements and actuators.
• the workpiece to be coated contains cutouts of any geometry. This is shown schematically in Figure 1.
• the workpiece (hatched diagonally) contains a recess (gray).
• a coating is created that covers the recess (black) and covers at least part of the workpiece.
• a further component (hatched horizontally) can then be inserted into the recess and, together with the workpiece, is covered by a uniform and undamaged coating.
• Preferred components are selected from the group consisting of sensors, lighting elements and actuators.
• a cavity remains between the inside of the shaping tool and the surface of the workpiece enclosed by the shaping tool.
• the reaction mixture is then introduced into the cavity.
• the complete mixing of all components of the reaction mixture can take place before the introduction, but it can also take place e.g. by means of suitable mixing units during the introduction.
• RIM systems such as those commercially available from Isotherm AG, Uetendorf, CH, for example under the name PSM 90 or PSM 3000, from the KraussMaffei Group, DE under the process / technology name ColorForm and from Hennecke GmbH, Sankt Augustin, DE under the process / technology name ClearRIM.
• the KrausMaffei Group, DE also offers optional color modules for the ColorForm system that can work with three components and thus allow, for example, a quick color change.
• the distance between the inside of the shaping tool and the surface of the workpiece to be coated is preferably between 50 ⁇ m and 5 mm. This distance is preferably determined along the normal to the surface of the workpiece.
• the coating preferably has an extension of at least 10 mm along at least one axis of a two-dimensional Cartesian coordinate system.
• the cavity is preferably filled with the reaction mixture under a pressure that is higher than the ambient pressure. During the curing process, the pressure in the cavity preferably also remains higher than the ambient pressure.
• the inside of the shaping tool preferably has a temperature between 60 ° C and 300 ° C.
• the coated workpiece can then be removed from the shaping tool.
• the above-mentioned upper limit of the temperature during curing is of course dependent on the nature of the workpiece to be coated. If this is damaged at a given temperature, the temperature during curing must be below this value.
• the upper limit is preferably 130 ° C, more preferably 100 ° C. In order to ensure sufficiently rapid curing, a preferred lower temperature limit is 80 ° C.
• the invention it is thus possible to build up a coating using an automated method. Since the curing of the reaction mixture takes place through the reaction of isocyanate groups with one another, the isocyanate groups according to the invention being in significant excess, and not primarily through the reaction of two different functional groups, the reaction mixture is less prone to mixing errors than two-component systems. A mechanical or chemical pretreatment of the tool to be coated is usually unnecessary. Even workpieces with more complex geometry, where a coating can only be applied with difficulty using conventional methods, can be coated in this way. Since the coating composition is cured, inter alia, through the formation of isocyanurate groups, the coatings obtained in this way have high mechanical and chemical resistance. If the polyisocyanate composition A contains only small amounts or no proportions of aromatic isocyanates, coatings that are very weather-resistant can be obtained.
• the present invention relates to a method for coating a workpiece comprising the steps of a) introducing a workpiece into a shaping tool which encloses at least part of the workpiece and which is dimensioned such that the distance between the surface of the workpiece and the The inside of the forming tool corresponds to the thickness of the coating; b) Filling in at least one reaction mixture with a molar ratio of isocyanate groups to isocyanate-reactive groups of at least 3: 1
• the workpiece can be introduced into the shaping tool in any manner known to a person skilled in the art of reaction injection molding.
• a cavity is located at at least one point between the surface of the workpiece to be coated and the inside of the shaping tool. This serves to take up the reaction mixture in process step b).
• Its thickness i.e. the distance between the surface of the workpiece and the inside of the forming tool, determines the layer thickness of the resulting coating.
• the structure of the surface of the resulting coating can be determined by the design of the inside of the shaping tool.
• the shaping tool encloses at least part of the workpiece in such a way that the cavity is sealed off from the outside and the reaction mixture filled in by valves or other suitable devices cannot run out of the cavity.
• reaction mixture is poured into the cavity. This can be done in any of the ways known to a person skilled in the art in the field of reaction injection molding. Depending on the reactivity of the reaction mixture used, the reaction mixture can be pre-mixed in a storage container. This is preferred for reaction mixtures which have a low reactivity at room temperature.
• the polyisocyanate A and the trimerization catalyst B are, however, preferably stored in separate containers and only mixed during the filling. Suitable valves, nozzles and mixing heads are well known to the person skilled in the art in the field of two-component polyurethane systems.
• the process according to the invention is less prone to mixing errors: Variations in the stoichiometry of catalyst and isocyanate influence the rate of curing, but not the properties of the finished coating. In contrast, variations in the stoichiometric ratio of NCO groups and OFI groups in the known polyurethane systems inevitably lead to materials with changed properties.
• the temperature of the reaction mixture is raised to at least 60 ° C. in process step.
• the selection of the suitable temperature depends on the one hand on the sensitivity of the workpiece to be coated. The hardening temperature must not reach a level that would damage the workpiece. Within this range, however, the choice of higher temperatures is generally preferred in order to achieve rapid curing and the associated short cycle times.
• An absolute upper limit for the curing temperature in the process according to the invention the material formed from the reaction mixture itself sets: Polyisocyanurate plastics decompose at temperatures above 300 ° C, so that this value is only exceeded for a maximum of 5 seconds, but preferably not at all, during process step c). Particularly suitable temperature ranges are disclosed further above in this application.
• Process step c) is carried out until the coated workpiece can be removed from the mold.
• the term "demouldable” denotes a state of the workpiece in which it can be removed from the shaping tool without residues of the reaction mixture sticking to the inside of the shaping tool. In this case, it is not necessary that all of the isocyanate groups have already reacted it is preferred that at the end of process step c) between 15 and 85%, more preferably between 30 and 75% and particularly preferably 40 to 75% of the isocyanate groups present at the beginning of process step c) have reacted. mirror image between 5 and 85%, more preferably between 25 and 70% and particularly preferably 25 to 60% of the isocyanate groups originally present.
• At least 40 mol%, preferably at least 50 mol% and most preferably at least 50 mol% of the free isocyanate groups present at the beginning of process step c) are converted to isocyanurate groups.
• the result is a coating, the crosslinking of which is largely mediated via isocyanurate groups.
• Such coatings are distinguished by their superior resistance to chemical and physical influences.
• the process according to the invention contains a process step following process step c), in which the free isocyanate groups still present at the end of process step c) at a temperature between 10 and 120 ° C, preferably between 10 and 40 ° C, are further networked outside of the shaping tool.
• This process step is preferably carried out until at least 95% of the isocyanate groups present at the beginning of process step c) have reacted.
• Process step c) is preferably carried out for 10 seconds to 900 seconds, more preferably for 10 seconds to 180 seconds and even more preferably for 10 seconds to 90 seconds. “Implementation” in this context means that the reaction mixture as a whole is in contact with the inside of the shaping tool for this period and said inside has a temperature between 60 ° C and 300 ° C.
• the coating preferably has a Tg of 40 ° C to 300 ° C, more preferably 60 ° C to 180 ° C.
• the workpiece consists of at least 90% by weight of a thermoplastic synthetic material and process step a) is preceded by a process step of manufacturing said workpiece by injection molding.
• process step a) is preceded by a process step of manufacturing said workpiece by injection molding.
• the present invention relates to a coating obtained or obtainable by the above-defined process according to the invention.
• This coating according to the invention is particularly preferred in infrared spectrometric analysis due to a ratio of the absolute peak heights of the CH2 band and the NH-d band of at least 0.85: 1 with a simultaneous ratio of the absolute peak heights of the isocyanurate band and the NH-d band of marked at least 5.5: 1.
• the greatest absolute intensity was determined for each band.
• the measurements were between 2900 and 3000 cm 1 , for NH-d between 1480 and 1600 cm 1 and for isocyanurate between 1590 and 1700 cm 1 .
• the Tg of the coating is 40 ° C. to 300 ° C., preferably 60 ° C. to 180 ° C.
• the coating is free of pigments and has a Hazen color number of at most 50, preferably at most 30.
• Hazen color numbers are preferably determined using a micro-haze plus device from Byk-Gardner GmbH, Geretsried, Germany, at an angle of 20 °.
• the coating preferably has a density of at least 0.95 g / cm 3 .
• the present invention relates to a workpiece coated with the coating defined above.
• FIG. 1A shows a workpiece (hatched diagonally) with a recess (gray) in plan view.
• Figure 1B shows a cross-section of the workpiece with the recess.
• Figure IC shows the cross-section of the workpiece after coating. The workpiece and recess are now covered by the coating (black).
• Figure ID shows a coated workpiece in which a component (hatched horizontally) was inserted into the original recess.
• the tests were carried out on a Battenfeld HM 370/1330 injection molding machine, combined with a laboratory piston dosing system for 2 components.
• the tool used was a DIN-A5 plate tool, which was coated with a mass of approx. 41 g of paint, which corresponds to a paint layer thickness of 280 ⁇ m to 390 ⁇ m.
• Desmophen XP 2488 branched polyester polyol, available from Covestro Deutschland AG, with the following properties:
• Desmophen C1100 linear, aliphatic polycarbonate polyester, available from Covestro Deutschland AG, with the following properties:
• the HDI polyisocyanate B1 containing isocyanurate groups was prepared according to EP-A 330 966, Example 11, using 2-ethylhexanol instead of 2-ethyl-1,3-hexanediol as the catalyst solvent. After the excess monomeric HDI had been separated off by means of thin-layer distillation, an HDI polyisocyanate with an NCO content of 22.9%, a viscosity of 1200 mPas at 23 ° C. and an average NCO functionality of 3.1 (calculated from the NCO content and number average molecular weight, determined by GPC measurement). Makrolon 2405/901510, black polycarbonate
• the catalyst was prepared according to EP 333 7836, Example 1a.
• the polyols Desmophen C1100 and Desmophen XP 2488 were used in a mass ratio of 70:30.
• the amount of catalyst used corresponds to a concentration of 2.91% by weight based on the total mass (component A + component B), calculated for degree of crosslinking 3.
• Component B polyisocyanate B1, for amount see table 1.
• Both components were heated to approx. 90 ° C before the experiment.
• the surface temperature of the tool was 117 ° C.
• the thermoplastic was melted in the extruder at 290 ° C and injected into the tool at a mold temperature set at 120 ° C.
• the experimental release agent L9500021 from Votteler was applied manually to the plate tool, with any external release agent generally being suitable for polyurethane systems.
• Degree of crosslinking 1 ratio of NCO groups to OH groups of 1: 1
• Degree of crosslinking 3 ratio of NCO groups to OH groups of 3: 1
• Table 1 Overview of the mixing ratios of polyol (A) to isocyanate (B) used and the degrees of crosslinking achieved with them, as well as the parameters set
• the residual NCO content of at least one component was determined by means of IR after the following times.
• an unreacted mixture of components A and B, mixed at room temperature was measured according to the degree of crosslinking and the peak contained therein for the NCO group at approx. 2200 cm 1 was normalized to 100%.
• the measurements were made on the infrared spectrometer, Bruker Tensor II, using a Platinum ATR unit. The spectrometer was controlled with the device software OPUS Version 7.5, which was also used for the evaluation. After baseline correction (rubber band method) and normalization to CH 2 / CH 3 (min. -Max. Normalization in the range 2800-3000 cm 1 ), a straight line between 2380 cm 1 and 2170 cm 1 was calculated for the area integration and the area above it was calculated.
• Table 2 Overview of the percentage content of residual NCO in the components with different degrees of crosslinking, measured after different time intervals. If the average value was below 5%, the development was not followed up.
• Hazen color numbers were determined with a micro-haze plus device from Byk-Gardner GmbHFI, Geretsried, Germany, at an angle of 20 °.
• the gloss of the coatings obtained was measured reflectometrically in accordance with DIN EN ISO 2813: 2014 at a 20 ° angle.
• TG Glass transition temperature
• DSC differential scanning calorimetry
• a small amount of the appropriate solvent (xylene, 1-methoxy-2-propyl acetate (MPA), ethyl acetate or acetone) was placed in a test tube, which was fitted with a cotton swab at the opening so that a solvent-saturated atmosphere inside the test tube originated.
• the test tubes were then placed on the paint surface with the cotton ball and remained there for 5 minutes. After wiping off the solvent, the film was tested for destruction / softening / loss of adhesion and assessed visually from 0 (no change) to 5 (paint surface destroyed).
• Pendulum damping was measured in accordance with DIN EN ISO 1522 (edition 2007-04-01) according to Koenig, the sample plates being described in accordance with DIN 1514.
• Table 4 Overview of the test results on direct coating components with various degrees of crosslinking. The tests were carried out in accordance with the descriptions above.

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