Adhesion properties of foam-containing particles based on polyimide or polyacrylate.

Abstract

The present invention relates to a method for producing functionalized expanded molded particles based on a thermoplastic substrate having a glass transition temperature of at least 100° C., which comprises functionalizing the base particles.

Description

[Technical Field]

[0001] The present invention relates to a method for producing functionalized expanded molded particles based on a thermoplastic substrate having a glass transition temperature of at least 100° C., which comprises functionalizing the base particles.

[0002] Prior art Methods for producing foams from expandable granules are known to those skilled in the art. Typically, as such granules, thermoplastic blowing agent-containing particles are heated, for example with steam, thereby volatilizing the blowing agent. The particles then expand due to the release of the blowing agent, forming a foam that is mainly closed-cell. These foams are then pressed together by the expansion of the particles, often at elevated temperatures, so that the individual particles acquire a certain adhesiveness to each other.

[0003] As long as functionalized foams are desired, those skilled in the art will use additional processes to provide functionality after foam production.For example, WO 2005 / 105404 discloses a method for producing foams, in which the granules used are functionalized after swelling and maturation.The disadvantage in this case is that only a portion of the surface of each granule can be accessed, making it impossible to achieve uniform functionalization.

[0004] A variant of this method, which includes an additional functionalization step, is described in EP 2937379. There, an emulsion containing a specific polymer is applied to the granules before expansion. The drawback of this variant is that the granules are coated, and the functionalization can easily be lost again, especially during pre-expansion, i.e., pre-foaming, especially if the coating has a different thermal expansion coefficient than the granules. Furthermore, since the coating cannot expand to the extent of the granules during pre-expansion, it is almost impossible to achieve as complete a coating of the granules as possible.

[0005] Alternatively, those skilled in the art use particles that already contain this functionality, for example, applied during a masterbatch process. In this case, the disadvantage is that unused functionality remains in the particles. This unused functionality, on the one hand, generates costs during production, and on the other hand, is a burden to the environment without providing any technical advantage.

[0006] All prior art solutions have in common that they require additional method steps which are disadvantageously time-consuming and costly.

[0007] Object of the invention Therefore, there is a need to provide improved methods for producing functionalized particles.

[0008] In particular, it is an object of the present invention to overcome or at least minimize the drawbacks of known methods of the prior art.

[0009] The object of the present invention is to provide functionalized pre-expanded particles, in particular in a manner that is as cost-effective and process-efficient as possible.

[0010] solution The object of the present invention is to a) providing base particles comprising at least one blowing agent and at least one nucleating agent; b) feeding the base particles into an apparatus suitable for moving and heating the base particles; c) simultaneously pre-expanding and functionalizing the base particles by contacting them with a solution or dispersion comprising at least one functionalizing agent, wherein the at least one functionalizing agent is an adhesive, and optionally one or more further functionalizing agents are used together with the adhesive in functionalizing the base particles, the particles being treated with a solution or emulsion of water and / or a solvent and at least one functionalizing agent so as to obtain functionalized particles having at their surface at least partially an adhesive layer and, optionally, one or more functionalizations; d) optionally drying the functionalized particles; e) optionally intermediate storage of the functionalized particles; f) mold-expanding the functionalized particles by heating in a molding vessel to form a functionalized particle expanded molded article. This is achieved by the process according to the invention for producing a functionalized expanded molded particle body based on a thermoplastic substrate having a glass transition temperature of at least 100°C, which comprises in the specified order:

[0011] Advantageous embodiments of the method according to the invention are set out in the following description and in the dependent claims.

[0012] Advantageously, the present invention has proven to be particularly process-efficient, since additional method steps can be omitted. As a result, the method is also cost-effective, since work steps and time are saved. Furthermore, no additional equipment is required to carry out possible additional method steps.

[0013] According to the present invention, the functionalization and pre-expansion are carried out in one process step, so that an additional functionalization step can be omitted.The present invention also has the advantage that the functionalization is very uniform and covers all functional particles, so that there is a uniform functionalization.

[0014] Method step a) The substrate of the base particle is thermoplastic and is preferably selected from the group consisting of polyimides and polyacrylates, preferably polymethacrylimides (PMI), polyetherimides (PEI), polymethyl(meth)acrylates (PM(M)A) and mixtures thereof.

[0015] In particular, the substrate is also completely free of polyolefins, especially polypropylene, which have glass transition temperatures below 50° C. and are therefore unsuitable as substrates for structural foams in high temperature applications.

[0016] The substrate has a glass transition temperature of at least 100°C. The substrate preferably has a glass transition temperature of at least 180°C. The glass transition temperature of the substrate typically refers to the pure substrate and not to the substrate containing the blowing agent. The glass transition temperature is typically measured by DSC at a heating rate of 10 K / min according to DIN EN ISO 11357-2 (published July 2014).

[0017] The base particles contain at least one blowing agent. Typically, the at least one blowing agent is present in the substrate, for example, dissolved. The at least one blowing agent serves the purpose of expanding the base particles under certain conditions, such as elevated temperatures. This expansion refers to an increase in the volume of the base particles.

[0018] The blowing agent is selected from the group consisting of volatile organic compounds having a boiling point at standard pressure below the glass transition temperature of the substrate, inorganic blowing agents, thermally decomposable blowing agents, and mixtures of the foregoing.

[0019] The volatile organic compound, which has a boiling point at standard pressure below the glass transition temperature of the substrate and is liquid at standard temperature (i.e., 25°C, 1013 mbar), is preferably selected from the group consisting of non-halogenated hydrocarbons, ketones, alcohols, halogenated hydrocarbons and mixtures of the above.

[0020] The ketone is preferably selected from acetone, methyl ethyl ketone, cyclohexanone, cyclononanone, diacetone alcohol and mixtures thereof. The ketone is more preferably selected from acetone, methyl ethyl ketone and mixtures thereof.

[0021] The non-halogenated hydrocarbon preferably contains 4 to 8 carbon atoms, and is more preferably selected from butane, pentane, hexane and mixtures of the above.

[0022] The alcohol is preferably selected from methanol, ethanol, isopropanol, n-propanol and mixtures of the above.

[0023] The blowing agents used in polymethacrylimides can be the following compounds or mixtures thereof: formamide, formic acid, urea, itaconic acid, citric acid, dicyandiamide, water, monoalkylurea, dimethylurea, 5,5'-azobis-5-ethyl-1,3-dioxane, 2,2'-azobis-N-butylisobutyramide, 2,2'-azobis-N-diethylisobutyramide, 2,2',4,4,4',4'-hexamethyl-2,2'-azopentane, 2,2'-azobis-2-methylpropane, dimethyl carbonate, di-tert-butyl carbonate, acetone cyanohydrin carbonate. , methyl hydroxyisobutyrate carbonate, N-methylurethane, N-ethylurethane, N-tert-butylurethane, urethane, oxalic acid, maleic acid, hydroxyisobutyric acid, malonic acid, cyanoformamide, dimethyl maleate, tetraethyl methane tetracarboxylate, n-butyl oxamate, trimethyl methane tricarboxylate, triethyl methane tricarboxylate, as well as monohydric alcohols having 3 to 8 carbon atoms, such as propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, tert-butanol and isobutanol.

[0024] For polymethyl(meth)acrylate, it is also possible to use copolymeric blowing agents that release volatile compounds under foaming conditions, which generally remain in the polymer in the form of (meth)acrylic acid repeat units. Examples of such copolymeric blowing agents, as is common knowledge, are isopropyl(meth)acrylate and tert-butyl(meth)acrylate.

[0025] Particularly preferred blowing agents include tert-butanol, n-heptane, MTBE, methyl ethyl ketone, alcohols having 1 to 4 carbon atoms, water, methylal, urea, tert-butyl methyl ether, isopropyl (meth)acrylate and / or tert-butyl (meth)acrylate. Particularly preferred blowing agents are tert-butyl (meth)acrylate, isopropyl (meth)acrylate, tert-butanol, isopropanol and poly(tert-butyl (meth)acrylate).

[0026] The ester is preferably selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate and mixtures of the foregoing.

[0027] The halogenated hydrocarbon is preferably selected from the group consisting of methyl chloride, ethyl chloride, dichloromethane, dichloroethane, dichlorodifluoromethane, dichlorotetrafluoroethane, trichlorofluoromethane, trichlorotrifluoroethane and mixtures of the foregoing.

[0028] The at least one blowing agent is particularly preferably selected from the group consisting of non-halogenated hydrocarbons, ketones, alcohols and mixtures of the above, and most preferably is a ketone or urea.

[0029] When the at least one blowing agent is an inorganic blowing agent, it is preferably selected from carbon dioxide, argon and mixtures of the above.

[0030] When at least one blowing agent is a thermally decomposable blowing agent, it is preferably selected from azodicarbonamide, p-toluenesulfonylsemicarbazide, 5-phenyltetrazole, and mixtures thereof. The thermally decomposable blowing agent has a decomposition temperature at which it begins to release gas, allowing the base particles to then expand.

[0031] The base particles typically contain (on average) 1 to 20 wt. %, preferably 7 to 15 wt. %, of blowing agent, based on the total mass of the base particles.

[0032] The base particles include a nucleating agent, preferably selected from the group consisting of talc, graphite, carbon black, titanium dioxide, nanoparticles (nanotubes, nanoplates, etc.), and mixtures of the foregoing. Optional nucleating agents advantageously improve cell morphology.

[0033] Nucleating agents used in polymethacrylimide foams can be the following compounds or mixtures thereof: inorganic salts and minerals insoluble in the reaction mixture, such as SiO2, ZnS, BPO4, NaCl, KCl, or inorganic polymers and their salts, such as ammonium polyphosphate.

[0034] The base particle comprises (on average) 0.01 to 3 wt. %, preferably 0.05 to 1 wt. %, of nucleating agent, based on the total mass of the base particle.

[0035] The base particles are preferably spherical or cylindrical. Spherical means that the base particles have no corners or edges. The ratio of the shortest diameter to the longest diameter of the spherical base particles is preferably in the range of 0.9 to 1.0, particularly preferably in the range of 0.95 to 0.99. Due to their spherical shape, the preferred spherical base particles and the functional particles obtained by pre-expansion can be easily transported by a pneumatic transport system and blown into a foaming mold.

[0036] The diameter of the base particles, preferably the preferred spherical or cylindrical base particles, is preferably in the range of 0.1 to 5 mm, more preferably in the range of 0.5 to 3 mm, particularly preferably 0.8 to 2 mm.

[0037] The dimensions of the cylindrical base particle are defined by its diameter and height, similar to the spherical base particle. In the case of the cylindrical base particle, the ratio of height to diameter is preferably in the range of 0.9 to 1.1, and particularly preferably, the cylindrical base particle has a diameter equal to its height. The base particle is neither a hollow particle nor a core-shell particle like a microsphere.

[0038] The average mass of the base particles is preferably 1 to 15 mg, more preferably 2 to 12 mg, in particular 3 to 10 mg, in which case the mass of the base particles is at least 50%, preferably 75%, in particular 90% of the range specified above.

[0039] Preferably, 90% of the base particles, particularly preferably 99% of the base particles, based on the total number of base particles, have a diameter of less than 5 mm.

[0040] The base particles and their preparation methods are known in the prior art or commercially available. Those skilled in the art can choose from a variety of methods. For example, the base particles can be obtained as follows: after melting the substrate in an extruder, a nucleating agent is added if necessary, and at least one foaming agent is added when the substrate is cooled. The base particles can then be mechanically formed, for example, using a perforated plate, a gear pump, etc. (see WO 2019 / 025245, page 3, lines 19-38).

[0041] Method step b) In method step b) of the method according to the invention, the base particles are fed into an apparatus suitable for moving and heating the base particles.

[0042] Suitable devices in the context of the present invention are, for example, a rotating heatable drum, a mixing vessel, or even a moving belt in combination with a heat source, preferably a pass-through oven. The moving belt is, for example, a conveyor belt that supplies the base particles to the heat source. In this context, it is advantageous for the conveyor belt to be equipped with a means for moving the base particles relative to one another, for example, a vibrating device, so that the base particles move back and forth on the belt.

[0043] The device is preferably a rotating, heatable drum or a mixing vessel. In particular, the device is a rotating, heatable drum. Such a drum has the lowest mechanical impact on the base particles and functional particles, combined with very efficient mixing of the base particles.

[0044] The device is suitable for base particle movement, which means unidirectional movement of the base particles (e.g., on a conveyor belt through an oven) and / or movement of the base particles relative to each other. The latter is preferably included. As a result, improved functionalization of the base particles is possible.

[0045] Those skilled in the art know many possibilities for supplying base particles to the device.For example, the base particles can be supplied manually (casting, pouring, shoveling) or mechanically with the aid of the device, for example, using a pump system.Depending on the device, the base particles can be placed inside the device (for example, in the case of a rotating heatable drum or mixing vessel) or part of the device (for example, on a conveyor belt so that the base particles can be supplied to the heat source).

[0046] The device has the possibility of heating the base particles. Many methods for this purpose are known to those skilled in the art. For example, it is possible to use a suitable infrared radiation source, radio waves, microwaves, hot air, one or more resistance ovens, or a combination of the above. Heat can be transferred to the base particles directly (e.g., by radiation) or indirectly (e.g., by the walls of a rotating, heatable drum or mixing vessel heated by steam or a similar heat source).

[0047] Method step c) In process step c) of the process according to the invention, the base particles are simultaneously pre-expanded and functionalized.

[0048] As a result, functionalized particles are obtained from the base particles. The functionalized particles are pre-expanded and contain functionality on at least a portion of their surface. Preferably, at least 20%, more preferably 40% of the surface (based on the total surface of the functionalized particle) is functionalized. This can be determined gravimetrically or spectroscopically depending on the particle and the functionalization.

[0049] The functionalized particles according to the invention differ from the pre-expanded granules known in the prior art, in particular by the functionalization applied to the surface.

[0050] The functionalized particles also still contain a portion of the blowing agent contained in the base particles. Preferably, the functionalized particles contain 5-12%, more preferably 6-10%, and even more preferably 7-9% of the blowing agent contained in the base particles.

[0051] The base particles are functionalized during pre-expansion by contacting them with a solution or dispersion containing at least one functionalizing agent. The functionalization is preferably carried out only during pre-expansion, so that the process according to the invention can be designed particularly efficiently. The functionalizing agent generates functionality on at least a portion of the surface of the base particles.

[0052] The base particles are contacted with a solution or dispersion containing at least one functionalizing agent by immersion, spraying, or other common methods, and those skilled in the art can determine the most suitable method by routine experimentation.

[0053] The solution or dispersion containing at least one functionalizing agent is preferably aqueous. Aqueous in this case means that at least 90% by weight, more preferably at least 99% by weight, of the total solvent in the solution or dispersion is water. For example, to improve the solubility of individual components or the stability of the dispersion, additional water-miscible solvents, such as acetone, alcohols (preferably alcohols containing 1 to 4 carbon atoms, more preferably alcohols containing 2 to 3 carbon atoms) or glycols (preferably ethylene glycol and propylene glycol), can be incorporated.

[0054] The functionalizing agent is preferably selected from the group consisting of biocides, fungicides, adhesives, fibers, dyes, pigments, conductive particles and mixtures of the foregoing.

[0055] Preferred biocides are antimicrobial agents, with silver being preferred. Silver having a d50 of ≦1 μm, and more preferably 250 nm, is preferably used. The d50 can be determined by dynamic light scattering, as described in "Measuring the Size of Nanoparticles in Aqueous Media Using Batch-Mode Dynamic Light Scattering," NIST Special Publication 1200-6 (Version 1.2, May 2015).

[0056] The fungicide may be an organic, inorganic or organometallic substance. Preferred fungicides are copper compounds, such as copper oxychloride, colloidal pure sulfur, azoles, morpholines or strobilurins.

[0057] Suitable adhesives are particularly capable of binding the individual functional particles together in further subsequent process steps, ideally by cohesively binding them together. According to the present invention, the adhesive is preferably selected from the group consisting of dextrin, casein, acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, polyvinyl alcohol resins, isocyanates, polyamide resins, mixtures and copolymers of the above. Alternatively, thermoplastic polymers may be used as adhesives.

[0058] In a preferred embodiment, at least one functionalizing agent is an adhesive. Optionally, the adhesive is used together with one or more additional functionalizing agents (selected from the group defined above). For example, adhesives and biocides are used together with the functionalizing agents. Particularly advantageously, this embodiment of the present invention makes it possible to reduce or even completely prevent the formation of defects (also known to those skilled in the art as blowholes or gussets) that may occur during molding (method step f)). This is particularly true in the case of molding involving sintering with (supersaturated) steam, since in this case, particularly contradictory phenomena may sometimes occur in the existing substrate. Since the temperature of the steam increases proportionally to the pressure, at the process temperature required for sufficient sintering of the functional particles, self-expansion may not occur or may occur only to an insufficient extent due to excessively high steam pressure. If a certain degree of self-expansion is not achieved in method step f), two possible scenarios may arise: 1. The surfaces of adjacent functionalized particles may not be pressed together tightly enough, resulting in insufficient sintering of the functionalized particles. 2. As already mentioned, even if the volume of the functionalized particles is increased, it may not be increased enough to fill the spaces between the functionalized particles, which may result in defects in the form of blowholes in the functionalized foam. This results in an inhomogeneous structure of the functionalized foam. This effect has a negative impact, particularly on the surface quality of the functionalized foam. In addition to possible optical defects, especially in downstream processes, such as the application of any top layer or film to the functionalized foam, this may lead to problems (excessive resin incorporation into the fiber-reinforced top layer, and thus too high component dimensions, or the penetration of blowholes in the decorative fabric or film). These possible defects can be advantageously avoided or at least reduced, particularly by this embodiment.

[0059] When using an adhesive as at least one functionalizing agent and using the temperature of (supersaturated) steam for sintering the functionalized particles, the blowing agent is preferably selected so that its boiling point is below the selected temperature at which the adhesive develops its adhesive properties, i.e., at which the appropriate reaction occurs, for example if a reactive adhesive is selected. At the same time, the latter temperature mentioned should be lower than the sintering temperature of the substrate containing at least one blowing agent.

[0060] When a thermoplastic polymer is used as an adhesive, the softening or melting point is below the processing temperature.

[0061] Suitable fibers are selected from the group consisting of carbon fibers, glass fibers, aramid fibers, basalt fibers, and mixtures thereof. The fibers particularly improve the mechanical stability of the functional particles and the functionalized foams produced therefrom. As a result, a subsequently applied laminate may be omitted in some cases.

[0062] Suitable dyes serve to color the functionalized particles and the expanded molded articles produced therefrom, and are preferably selected from the group consisting of organic dyes.

[0063] Suitable pigments serve to color the functional particles and the functionalized particle foam molded articles produced therefrom, or to impart other functionality, such as increased UV resistance. One difference from the dyes mentioned above is that pigments generally cannot be dissolved in a solvent (preferably water according to the present invention) and therefore must be dispersed. A preferred example for increasing UV resistance is the use of nanoparticle titanium dioxide in the rutile form.

[0064] Suitable electrically conductive particles are selected from the group consisting of conductive carbon black, graphite, graphene, and carbon nanotubes (CNTs). The electrically conductive particles impart electrical conductivity to the functionalized particles and the resulting functionalized particle foams, or at least an antistatic coating, depending on the amount applied.

[0065] Those skilled in the art will select the amount of at least one functionalizing agent in the solution or dispersion depending on the desired functionalizing agent, the amount to be applied to the surface of the base particles, and the temperature used. Typical amounts are 0.1 to 50% by weight, preferably 1 to 30% by weight, more preferably 5 to 10% by weight, based on the total amount of the solution or dispersion.

[0066] Optionally, the solution or dispersion additionally comprises further additives such as wetting agents, stabilizers or rheological additives, etc. These additives and their uses are known and commercially available.

[0067] Suitable solutions or dispersions may be commercially available or may be prepared by standard methods. For example, the functionalizing agent and further additives, such as wetting agents, stabilizers, or rheological additives, may be dissolved or dispersed in a solvent. Such preparation methods are known to those skilled in the art.

[0068] The duration of method step c) is preferably in the range of 1 second to 15 minutes, preferably in the range of 5 seconds to 10 minutes, more preferably in the range of 10 seconds to 5 minutes. Durations outside the mentioned ranges may also apply depending on the temperature and functionalizing agent used.

[0069] Process step c) is carried out in the apparatus of process step b). The temperature inside the apparatus in process step c) is usually between the boiling point or decomposition point (at standard conditions) of the blowing agent and the glass transition temperature of the substrate. The temperature inside the apparatus in process step c) is preferably in the range of at least 10°C higher than the boiling point or decomposition point (at standard conditions) of the blowing agent and at most 10°C lower than the glass transition temperature of the substrate.

[0070] For example, when using acetone as the blowing agent, talc as the nucleating agent, and polyetherimide as the substrate, the temperature inside the apparatus in process step c) is in the range of 56° C. to 230° C., preferably in the range of 65° C. to 200° C. The temperature in process step c) can be adjusted by the methods described above.

[0071] The base particles are pre-expanded inside the device at a set temperature. The set temperature converts part of the blowing agent present in the base particles into a gas phase and expels it from the base particles, causing the base particles to undergo volume expansion. According to the present invention, this is referred to as pre-expansion. This pre-expansion differs from final expansion (in process step f) in that the particles then still contain the blowing agent, and further volume increase and sintering occur or can occur due to subsequent expansion.

[0072] An advantage of the present invention is that the growing surface of the base particles during pre-expansion is also in contact with a solution or dispersion containing at least one functionalizing agent, so that any defects in the functionalizing layer, such as cracks or peeling, are immediately repaired again.

[0073] In a preferred embodiment, the base particles in process step b) are fed into a heatable rotating drum, and in process step c) a solution or dispersion comprising at least one functionalizing agent is sprayed onto the drum while the drum is heated and rotated so that the base particles move against each other during pre-expansion and functionalization. This preferred embodiment allows a particularly efficient implementation of the process according to the invention and a particularly uniform functionalization of the base particles.

[0074] According to the invention, the functionalized particles can be fed directly into the mold foaming process in method step f).

[0075] Method step d) The process according to the invention preferably comprises, after process step c), a further process step d): d) Optionally, drying the functionalized particles. Includes.

[0076] The functionalized particles are dried in process step d) until the solvent of the solution or dispersion comprising at least one functionalizing agent is substantially removed, which preferably means that at least 90% by weight, preferably at least 99% by weight, of the solvent adhering to the functionalized particles after process step c) is removed in process step d).

[0077] Typically, drying is carried out at elevated temperatures, for example in the range of 25 to 90°C, preferably 40 to 60°C, to ensure efficient removal of the solvent without damaging the functionalized particles due to potentially too high temperatures.

[0078] The drying period is selected depending on the desired degree of solvent removal and the temperature. Typical drying times range from 1 minute to 10 days.

[0079] Those skilled in the art can select from a number of methods. For example, after releasing or removing the solution or dispersion containing at least one functionalizing agent, the functionalized particles can be placed in a device suitable for transferring and heating the base particles, and the temperature can be adjusted accordingly. Alternatively, the functionalized particles can be transferred to an oven or the like for this purpose.

[0080] Drying has the advantage that the functionalized particles remain free-flowing and therefore agglomeration (clumping) is prevented.

[0081] Preferably, the conditions applied in process step c) have already removed most of the solvent, so that the amount of solvent adhering to the functionalized particles after process step c) is already so low that process step d) is not required.

[0082] Method step e) The method according to the invention preferably comprises a further method step e): e) optionally, temporarily storing the functionalized particles Includes.

[0083] Process step e) is carried out after process step c) or, if process step d) of the process according to the invention is included, after process step d).

[0084] Process step e) advantageously equalizes pressure between the functionalized particles and the ambient environment. During pre-expansion, the blowing agent is heated and expands. After pre-expansion is complete, the blowing agent condenses again. This condensed blowing agent creates negative pressure in the foam cells, which can have a negative effect on the foamed molded article. Process step e) prevents this, since ambient air would diffuse into the functionalized particles.

[0085] Typically, temperatures in the range of 0 to 30° C., preferably 15 to 25° C., are used. Excessively high temperatures can lead to undesired release of the blowing agent.

[0086] The period is not further limited, and the functionalized particles can be temporarily stored for as long as desired. The period of temporary storage can be determined by those skilled in the art depending on the substrate used and the amount of foaming agent released, and is, for example, 30 minutes to 72 hours, preferably 2 hours to 48 hours, and more preferably 4 hours to 24 hours.

[0087] Method step f) The method according to the invention may further comprise a further method step f): f) forming the functionalized particles by heating them in a molding vessel to form a foamed molded product of the functionalized particles; Includes.

[0088] Process step f) is incorporated into the process according to the invention after process step c), or after process step d) if process step d) is included, or after process step e) if process step e) is included.

[0089] The shaping of pre-expanded granules is known to those skilled in the art.

[0090] For molding, at least two functionalized particles are heated. Generally, a large number of functionalized particles are heated. The amount of functionalized particles varies depending on the desired shape. The temperature used for this purpose mainly depends on the substrate, the foaming agent present therein, and the method used. Typically, this temperature is set to a range from the glass transition temperature of the functionalized particles to a temperature 10°C higher than the glass transition temperature of the substrate, preferably from the glass transition temperature of the functionalized particles to the glass transition temperature of the substrate. Temperatures significantly higher than the specified temperature may lead to undesired melting of the functionalized particles, which may result in loss of shape.

[0091] The molding period depends primarily on the substrate, the foaming agent present therein, and the method used. Those skilled in the art can determine a suitable period by routine experimentation or obtain it from the prior art. Typically, the period is between 10 seconds and 120 minutes.

[0092] The forming vessel can be, for example, a press or another suitable vessel and is determined, inter alia, by the desired shape of the functionalized foam.

[0093] After molding, a top layer or film is optionally applied to the formed functionalized particle foam. Such top layers and films, and methods for their application, are known to those skilled in the art.

[0094] Functionalized particles In another aspect, the present invention relates to functionalized particles, preferably producible or produced by the method according to the present invention, comprising at least one blowing agent, at least one nucleating agent, and at least one thermoplastic substrate having a glass transition temperature of at least 100°C and having at least one functionality on at least a portion of its surface.

[0095] Functionalized particle foam molding In a further aspect, the present invention relates to a functionalized particle foam molded article produced from the functionalized particles. The functionalized particle foam molded article is preferably produced by the method according to the present invention, which additionally comprises at least method step f).

[0096] The functionalized particle foam moldings contain at least two, and generally many, cells formed from the functionalized particles in process step c). Typically, each functionalized particle forms one cell of the functionalized particle foam moldings. The average cell diameter of the expanded functionalized particle foam moldings according to the present invention is generally in the range of 30 to 500 μm, preferably in the range of 50 to 300 μm. Preferably, 90% of the cells, particularly preferably 99% of the cells, have a cell diameter of less than 150 μm. The average length / width ratio is preferably less than 2.0, more preferably less than 1.6, particularly preferably 0.9 to 1.1.

[0097] The functionalized particle expanded molded articles thus obtained generally have closed cells. 3 in the range of 40 to 150 kg / m 3 It has a density in the range of

[0098] The functionalized particle foam moulded articles according to the invention are suitable for use in the manufacture of articles for the aerospace industry, shipbuilding, wind power generation, sports and leisure goods, vehicle construction, in particular the manufacture of electric mobility.

[0099] The functionalized particles and the resulting functionalized particle foam moldings are suitable for the production of automotive parts, such as sun visors, column cladding, roof lining, trunk and spare wheel covers, or parcel shelves. Typical examples are also semi-finished products (e.g. panels) for the production of furniture and the furniture itself, toys, outdoor equipment, machine cladding, etc.

[0100] The method according to the invention, as well as the functionalized particles and the expanded molded functionalized particles produced therefrom, are particularly suitable for high temperature applications.

[0101] Example Example 1: Base polymer: Polyetherimide (Type: ULTEM™ 1000, Manufacturer: SABIC) Nucleating agent: Talc (type: Luzenac, manufacturer: IMERYS) Blowing agent: acetone Functionalization: biocides (e.g. silver) Pre-foaming oven: rotary oven with infrared irradiation field (type: IRD90 / 100, manufacturer: Kreyenborg GmbH) Reaction speed: 30 min -1 Preheating: 90℃ for 15 minutes Pre-foaming: 155°C for 5 minutes Addition and metering of reaction solution: 0.1 L / min for 2 minutes Bulk density of base particles: 740 kg / m 3 Bulk density of functionalized particles: 90 kg / m 3

[0102] After melting the polyetherimide (type: ULTEM™ 1000, manufacturer: SABIC) in an extruder, the nucleating agent talc (type: Luzenac, manufacturer: IMERYS) is added, and the blowing agent acetone is added when the substrate is cooled. The base particles can then be mechanically formed using a perforated plate.

[0103] The base particles are fed into a heatable rotary oven (rotary oven with infrared radiation field (type: IRD90 / 100, manufacturer: Kreyenborg GmbH)) and in process step c) sprayed with a dispersion containing the functionalizing agent silver (biocide) while the drum is heated and rotated so that the base particles move against each other during pre-expansion and functionalization. This preferred embodiment allows for a particularly uniform functionalization of the base particles.

[0104] Example 2: Base polymer: Polymethacrylimide (Type: ROHACELL® Triple F, Manufacturer: Evonik) Glass transition temperature: 217°C (measured by DSC in accordance with DIN EN ISO 11357-2 (published July 2014)) Nucleating agent: SiO2 Foaming agent: urea Functionalization: Adhesive (Type: Dynacoll, Manufacturer: Evonik) Pre-foaming oven: continuous oven with infrared irradiation field (manufacturer: Fill GmbH) Conveyor speed: 0.5m / min Preheating:- Pre-foaming: Continuous at 210℃ Addition and metering of reaction solution: Continuous at 0.1 l / min Bulk density of base particles: 600 kg / m 3 Bulk density of functionalized particles: 140 kg / m 3

[0105] After melting polymethacrylimide (type: ROHACELL® Triple F, manufacturer: Evonik) in an extruder, the nucleating agent SiO2 is added, and the foaming agent urea is added when the substrate is cooled. The base particles can then be mechanically formed using a perforated plate.

[0106] The base particles are fed into a heatable rotary oven (continuous oven with infrared radiation field, manufacturer: Fill GmbH) and in process step c) sprayed with a dispersion containing the functionalizing agent adhesive (type: Dynacoll, manufacturer: Evonik) while the drum is heated and rotated so that the base particles move against each other during pre-expansion and functionalization. This preferred embodiment allows for a particularly uniform functionalization of the base particles.

Claims

1. 1. A method for producing a functionalized expanded molded particle body based on a thermoplastic substrate having a glass transition temperature of at least 100°C, as measured by DSC according to DIN EN ISO 11357-2 (published July 2014), comprising: a) providing base particles comprising at least one blowing agent and 0.01 to 3 wt. % of at least one nucleating agent, based on the total weight of the base particles; b) feeding the base particles into an apparatus suitable for moving and heating the base particles; c) simultaneously pre-expanding and functionalizing the base particles by contacting them with a solution or dispersion comprising at least one functionalizing agent, wherein the at least one functionalizing agent is an adhesive, and optionally one or more further functionalizing agents are used together with the adhesive for functionalizing the base particles, the particles being treated with a solution or emulsion of water and / or solvent and at least one functionalizing agent so as to obtain functionalized particles having at their surface at least partially an adhesive layer and, optionally, one or more functionalizations; d) optionally drying the functionalized particles; e) optionally, temporarily storing the functionalized particles; f) mold-expanding the functionalized particles by heating in a molding vessel to form a foamed molded product of the functionalized particles. in the specified order, A method wherein said substrate is selected from the group consisting of polyimides and polyacrylates, preferably polymethacrylimides (PMI), polyetherimides (PEI), polymethyl(meth)acrylates (PM(M)A) and mixtures of the above.

2. 2. The method of claim 1, wherein the blowing agent is selected from the group consisting of volatile organic compounds having a boiling point at standard pressure below the glass transition temperature of the substrate, inorganic blowing agents, thermally decomposable blowing agents, and mixtures of the foregoing.

3. 10. The method of claim 1, wherein the functionalizing agent is selected from the group consisting of biocides, fungicides, adhesives, fibers, dyes, pigments, conductive base particles, and mixtures of the foregoing.

4. Use of functionalized expanded particle molded articles produced by the method according to any one of claims 1 to 3 in the manufacture of articles for the aerospace industry, shipbuilding, wind power generation, sports and leisure goods, vehicle manufacturing, in particular the manufacture of electric mobility.