Process for producing single-material particle-foam components

Abstract

The present invention relates to a process for producing a mono-material particle-foam component based on a thermoplastic base polymer, characterized in that an expandable base polymer is processed into a mono-material particle-foam component together with a modified base polymer.

Description

[Technical Field]

[0001] The present invention relates to a process for producing a mono-material particle-foam component based on a thermoplastic base polymer, characterized in that an expandable base polymer is processed into a mono-material particle-foam component together with a modified base polymer. [Background technology]

[0002] The increasing use of lightweight construction materials is leading to rapid further development of this technology. In addition to the search for suitable materials, production processes are also opening up more and more new fields of application.

[0003] The use of polymer foams is gaining attention here. Foam materials suitable for fittings in the aviation industry are well known. These are mainly foams composed of pure PMI (polymethacrylimide), PPSU (polyphenylene sulfone) or PES (polyether sulfone). PARI (polyaryl imide) is also described in the literature, but is unsuitable from a toxicological point of view. All these materials have so far mainly been used as block or slab materials.

[0004] Polymer foams based on polyetherimide (PEI) meet the legal requirements for aircraft interiors set by the aviation industry. In particular, the requirements regarding flame behavior, stability to media, and mechanical properties represent major challenges here.

[0005] Depending on the application, the polymer foams are provided with cover layers, inserts, fastening elements, etc. Particular requirements are placed on these elements in terms of their endurance strength, elasticity or non-destructive disassembly, especially in the aeronautical industry. The disadvantages of known joining techniques from the prior art, such as gluing, welding or riveting, are that these joining methods are difficult to monitor, the process reliability is limited and the preparation and finishing of the joint involves a lot of work.

[0006] Materials are joined by adhesive and cohesive forces. These are non-removable bonds that can only be separated by destroying the joining means. The most well-known material joining processes are soldering, welding, and adhesive bonding.

[0007] One recent process describes the use of plastic bosses, for example in hollow chamber structures. These can be used as screw bosses or direct joining elements. Depending on the design, these can be removable or non-removable joints. The joining element is placed on the components to be joined and subjected to a specified rotation speed and force, heating the top layer. This causes the top layer to rub off. The molten joining element penetrates the components and flows into the hollow chamber of the intermediate layer. This creates an undercut that creates a form-fitting joint.

[0008] This joining technique is used in automotive engineering when the tool is only accessible from one side during screwing or when, for aesthetic reasons, only one side should be processed.

[0009] Processes for producing foams from expandable granules are known to those skilled in the art. Such granules are typically blowing agent-containing particles of thermoplastic material that are heated, e.g., with steam, to volatilize the blowing agent. The release of the blowing agent causes the particles to expand, forming a primarily closed-cell foam. These foams are often pressed together by the resulting particle expansion, often at high temperatures, resulting in the individual particles gaining a certain adhesion to one another.

[0010] The foams are optionally reinforced with fabric layers or materials to secure them in place, and are equipped with inserts. Inserts are usually made of metal or plastic. The choice of insert usually depends on the task and mechanical requirements, as well as economic aspects. This is the usual method of mixing materials. For example, PEI foam blocks are equipped with metal inserts.

[0011] What all prior art processes have in common is the mixing of plastic and metal materials, or other materials, which makes recycling very difficult and is therefore not usually done.

[0012] The single material system of foam and compact element cannot be materially joined in the process because the thermal processing windows are not compatible.

[0013] The use of adhesives this requires adversely affects the weight properties of the molded parts.

[0014] WO 2017 / 109079 relates to a method for producing a molded body from a particulate foam material in a closable mold cavity of a mold tool, the method comprising introducing a particulate foam material in granular form into the mold cavity of the mold tool, closing the mold cavity, and heating the mold tool and the granules contained therein, whereby the granule particles are bonded to one another. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Publication No. 2017 / 109079 Summary of the Invention [Problem to be solved by the invention]

[0016] Object of the invention The object of the present invention was to overcome or at least minimize the drawbacks of known prior art processes.

[0017] For recycling purposes, mixing of materials should be avoided. A corresponding single-material system joins foam parts with non-foamed joining elements.

[0018] Against the background of the prior art discussed, the object of the present invention is in particular to provide a process for producing components made of high temperature (HT) foam that is simpler and more effective compared to the prior art, making it possible to materially join foam components with non-foamed joining elements. [Means for solving the problem]

[0019] The problems detailed above can be solved specifically by lowering the glass transition temperature of the compact component to the level of the processing temperature of the foam, thereby achieving material bonding in a single material system.

[0020] This object has been achieved more particularly by a process for producing a mono-material particle-foam component based on a thermoplastic base polymer, characterized in that an expandable base polymer is processed into a mono-material particle-foam component together with a modified base polymer.

[0021] The process of the present invention comprises process steps a), b), c), d), e), and f), which are performed in the specified order. Additionally, the process of the present invention optionally comprises process step g), which is performed after process step f).

[0022] The embodiments and preferences described in this specification and claims can be combined with one another without restriction, unless expressly excluded or technically impossible.

[0023] When the term "at least one" is used in the claims or specification, it refers to the selection of "one" and "two or more." DETAILED DESCRIPTION OF THE INVENTION

[0024] The process of the present invention comprises: a) providing an expandable base polymer, which may optionally already be pre-expanded; b) providing a modified base polymer; c) providing the modified base polymer to a processing operation; and providing a foamable base polymer, optionally already pre-foamed; d) setting the processing temperature TP by supplying energy; and e) creating a material bond between the foamed base polymer and the modified base polymer; f) removing the resulting single material particle-foam component; g) optionally, heat treating the resulting single-component particle-foam component. Includes:

[0025] Glass transition temperature Tg of the base polymer measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07) ベースポリマー less than the glass transition temperature Tg 改変されたベースポリマー It has been found that specific modifications of the base polymer to make it possible to produce a single material particle-foam component.

[0026] Surprisingly, it has been found that a base polymer can be processed into a modified base polymer by adding at least one solvent, blowing agent, or plasticizer. Thus, the modification of a thermoplastic base polymer to produce a modified base polymer can be carried out by adding at least one solvent, blowing agent, or plasticizer to the thermoplastic base polymer. In particular, the glass transition temperature, Tg, of the base polymer can be increased by adding at least one solvent, blowing agent, or plasticizer. ベースポリマー less than the glass transition temperature Tg 改変されたベースポリマー Therefore, the glass transition temperature Tg of the base polymer can be calculated. ベースポリマー less than the glass transition temperature Tg 改変されたベースポリマーThe modification of the thermoplastic base polymer to produce a modified base polymer having Tg can be accomplished, inter alia, by adding at least one solvent, blowing agent, or plasticizer to the thermoplastic base polymer. Other substances that lower the Tg of the base polymer can also be used to modify the base polymer.

[0027] Particle foams containing a blowing agent, eg, residual blowing agent, have a lower glass transition temperature than compact polymers that do not contain a blowing agent.

[0028] The single-material particle foam component according to the present invention is a combination of an expandable base polymer and a modified base polymer. The modified base polymer can be obtained by treating the base polymer with a solvent, blowing agent, or plasticizer, for example, by spraying, dipping, wetting, or mixing. Such treatment with a solvent, blowing agent, or plasticizer results in a decrease in the glass transition temperature of the base polymer. Therefore, the modified base polymer can be obtained or is obtained by such treatment. Subsequent processing of the modified base polymer with the expandable base polymer results in the formation of a single-material particle-foam component by material bonding.

[0029] Process step a) In process step a) of the process of the present invention, an expandable base polymer is provided. The expandable base polymer is produced from a thermoplastic base polymer by adding a blowing agent.

[0030] It is preferred to use a thermoplastic base material which has a glass transition temperature of at least 100°C, more preferably above 150°C, most preferably above 180°C, measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07).

[0031] The thermoplastic base polymer is selected from the group consisting of polyimides, polyketones and polyacrylates, preferably polymethacrylimide (PMI), polyetheretherketone (PEEK), polyetherimide (PEI), polymethyl(meth)acrylate (PM(M)A), polyethylene terephthalate (PET), polysulfone (PSU), polyethersulfone (PESU), polyphenylenesulfone (PPSU), polyamide (PA) or mixtures thereof.

[0032] It is preferred to use a blowing agent selected from the group consisting of volatile organic compounds having a boiling point at standard pressure lower than the glass transition temperature of the base polymer, inorganic blowing agents, thermally decomposable blowing agents, and mixtures thereof. At least one blowing agent is preferably a volatile organic compound having a boiling point at standard pressure lower than the glass transition temperature of the base polymer.

[0033] The volatile organic compound having a boiling point at standard pressure below the glass transition temperature of the base polymer and being liquid at standard temperature (e.g., 25°C, 1013 mbar) is preferably selected from the group consisting of non-halogenated hydrocarbons, ketones, alcohols, urea, halogenated hydrocarbons, and mixtures thereof.

[0034] 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.

[0035] The non-halogenated hydrocarbon preferably contains 4 to 8 carbon atoms. The non-halogenated hydrocarbon is more preferably selected from pentane, hexane and mixtures thereof.

[0036] The alcohol is preferably selected from methanol, ethanol, isopropanol, n-propanol and mixtures thereof.

[0037] The ester is preferably selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate and mixtures thereof.

[0038] The halogenated hydrocarbon is preferably selected from the group consisting of methyl chloride, ethyl chloride, dichloromethane, dichloroethane, dichlorodifluoromethane, dichlorotetrafluoroethane, trichlorofluoromethane, trichlorotrifluoroethane and mixtures thereof.

[0039] When the at least one blowing agent is an inorganic blowing agent, it is preferably selected from carbon dioxide, argon and mixtures thereof.

[0040] If the at least one blowing agent is a thermally decomposable blowing agent, it is preferably selected from azodicarbonamide, p-toluenesulfonylsemicarbazide, 5-phenyltetrazole, and mixtures thereof. Thermally decomposable blowing agents have a decomposition temperature above which they release gas, thereby allowing the base particles to expand.

[0041] Foam particles are understood to mean regions in particle foams defined by individual unexpanded or pre-expanded particle foams. The boundaries between individual interconnected foam particles are easily visible to the naked eye or can be determined under an optical microscope. This applies particularly when the interface between two foam particles is clearly identifiable. However, this is not always the case, so a simplified method is used in accordance with the present invention: the theoretical average diameter of the foam particles is simply calculated from the diameter of the unexpanded particles, the total volume of the unexpanded particles, and the volume of the finished foam part. Those skilled in the art will recognize that it is possible to achieve a regular size distribution of the foam particles in particle foams, with small deviations occurring only in the edge regions of the foam part.

[0042] Unless otherwise specified, the glass transition temperatures described herein are measured by DSC (differential scanning calorimetry), more specifically, by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07). Those skilled in the art will recognize that DSC is only fully informative if, after a first heating cycle to a temperature at least 25°C higher than the highest glass transition temperature or melting temperature but at least 20°C lower than the material's lowest decomposition temperature, the material sample is held at this temperature for at least 2 minutes. The sample is then cooled again to a temperature at least 20°C lower than the lowest glass transition temperature or the melting temperature to be determined, with the cooling rate being no more than 20°C / min, preferably no more than 10°C / min. After a further waiting period of a few minutes, the actual measurement is performed, with the sample heated to a temperature at least 20°C higher than the highest melting temperature or glass transition temperature, typically at a heating rate of no more than 10°C / min.

[0043] The foams of the present invention preferably have a degree of expansion equivalent to a reduction in density of 1% to 98%, preferably 50% to 97%, more preferably 70% to 95% compared to the unfoamed material. The foams preferably have a density of 20 to 1000 kg / m 3 , preferably 40 to 250 kg / m 3 , more preferably 50 to 150 kg / m 3 It has a density of

[0044] The base polymer typically (on average) has a blowing agent content of 1% to 20% (by weight), preferably 3% to 18% (by weight), more preferably 7% to 16% (by weight), based on the total composition.

[0045] Those skilled in the art are aware of suitable processes for producing particle foams (for example, EP 3673009). These known processes give granules (expandable base polymer) that contain a blowing agent.

[0046] These expandable base polymers can optionally be pre-expanded.

[0047] The energy input required for pre-expansion can be achieved by contact heat, for example in a convection oven, by steam, or by irradiation with IR or microwave radiation. The pre-expanded base polymer still contains 0.5% to 12% (by weight) of blowing agent.

[0048] This process provides an expandable base polymer, optionally pre-expanded, which can then be expanded to a desired density by a new supply of energy and / or further processed into a particulate foam article, optionally by molding.

[0049] Process step b) In process step b) of the process of the present invention, a modified base polymer is provided.

[0050] The process of the present invention is characterized in that the modification of the base polymer to produce the modified base polymer is accomplished by adding a solvent, blowing agent, plasticizer, or other substance that lowers the Tg of the base polymer, for example, by spraying, dipping, steaming, wetting, or mixing with the solvent, blowing agent, plasticizer, or other substance that lowers the Tg of the base polymer.

[0051] It is preferred to use the blowing agent as a solvent.

[0052] If the modified base polymer is available as a semi-finished product, a wide range of applications arises. Examples include plates, panels, blocks, round bars, hollow rods, tubes, hoses, but also rods and profiles. However, it is also possible to use semi-finished products that have been further processed. Inserts, plastic carriers, and connecting elements such as screws, hooks, eyelets, springs, clamps, and other connecting elements can in particular be used as modified base polymers (compact materials).

[0053] The base polymer, also referred to herein as compact material, is contacted with a blowing agent, solvent, or plasticizer at a temperature above the melting temperature of the solvent for a time period of 1 second to 80 hours. This results in a modification of the compact material, preferably a modification of the surface of the compact material. The modification manifests itself in a lowering of the glass transition temperature Tg, particularly at the surface. The modified base polymer thus obtained has a glass transition temperature Tg 改変されたベースポリマー This is again determined by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07).

[0054] Ideally, the glass transition temperature is lowered only at the surface of the compact material. For optimal processing, the glass transition temperature of the modified base polymer is lowered to at least the processing temperature TP of the expandable base polymer.

[0055] The modified base polymer has a glass transition temperature Tg of the base polymer measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07). ベースポリマー less than the glass transition temperature Tg 改変されたベースポリマー It has.

[0056] Process step c) Process step c) of the process of the present invention involves feeding the modified base polymer, and optionally the expandable base polymer, which has already been pre-expanded, to a processing operation.

[0057] The modified base polymer (compact material) is available in any geometric shape.

[0058] These modified base polymers can be freely added to the processing operation. In a preferred variant, they can be inserted into a molding tool. Preferably, the modified base polymer is inserted into the molding tool at a predetermined point and may optionally be fixed to ensure accurate positioning.

[0059] The mold is then closed and filled with the expandable base polymer through the provided supply lines, which preferably occur through injection points within the mold after the mold is closed. In process step c), not only the expandable base polymer that has not yet been pre-expanded, but also the pre-expanded but still expandable base polymer (pre-expanded material) can be fed to the processing operation, preferably to a molding tool.

[0060] The pre-expanded base polymer is obtained from the expandable base polymer by a pre-expansion process known to those skilled in the art. Typically, some, but not all, of the blowing agent is activated for pre-expansion by the supply of energy, preferably by increasing the temperature.

[0061] After pre-expansion, the blowing agent content in the expandable base polymer is lower, but still sufficient to expand into a finished particle-foam component in the subsequent expansion process.

[0062] The pre-foamed material can be fed directly to process step c) or optionally deployed elsewhere.

[0063] After pre-expansion, condensation of the blowing agent during cooling creates a negative pressure within the particles. When deployed elsewhere, the pressure can be equalized to ambient pressure. In one particular embodiment, the expandable, optionally pre-expanded, base polymer is introduced before the mold is closed.

[0064] Process step d): In process step d) of the process of the invention, the processing temperature TP is set by the supply of energy.

[0065] Energy is supplied to the processing operation, more specifically to the mold, by means known to those skilled in the art. Heating is usually achieved by jacket heating of the mold. The base polymer as well as the modified base polymer are heated to a temperature TP higher than the glass transition temperature Tg of the foamable base polymer and the glass transition temperature Tg of the base polymer.

[0066] The processing temperature TP is higher than the pre-expansion temperature.

[0067] Depending on the design of the mold support, the closed mold can also be pressurized, typically between 0.5 and 10 bar, preferably between 3 and 8 bar.

[0068] Process steps e): In process step e) of the process of the present invention, a material bond between the foamed base polymer and the modified base polymer is created.

[0069] As a result of the temperature increase above the foaming temperature, the foamable, optionally pre-foamed, base polymer softens and further foams, which results in a material bond with the modified base polymer (compact material).

[0070] Examples of methods include pressing processes (also called compression molding in the prior art), e.g. hot pressing by electrical heating, by heat transfer medium or by induction, bonding, sintering with (supersaturated) steam or the use of electromagnetic radiation such as radio waves and microwaves.

[0071] A variation of the process of the present invention involves steam treatment of the foamable, optionally pre-foamed, base polymer to initiate the foaming process.

[0072] The duration of molding depends mainly on the base material, the foaming agent present therein, and the method used. Those skilled in the art can determine the appropriate processing time by routine testing or can obtain it from the prior art.

[0073] Process step e) is carried out at the processing temperature TP for a period of a few seconds to a few minutes, preferably 1 second to 3 hours, more preferably 5 seconds to 60 minutes, most preferably 10 seconds to 10 minutes.

[0074] In process step e), the processing temperature TP is adjusted to the glass transition temperature Tg of the modified base polymer. 改変されたベースポリマー It is preferable that this is equal to or greater than this.

[0075] As an example, the following sequence can be envisaged: Tg 発泡性ベースポリマー ≦Tg 改変されたベースポリマー ≦TP (Processing Temperature) <Tg ベースポリマー (Compact material).

[0076] Process step f) In process step f) of the process of the invention, the obtained single-component particle-foam component is removed. For this, the mold is optionally cooled before being opened. The single-material particle-foam component is removed manually or with a gripper.

[0077] After molding, a cover layer or film is optionally applied to the formed single-material particle-foam component. Such cover layers and films and methods for their application are known to those skilled in the art.

[0078] Optional process step g) In optional process step g), the single material particle-foam component is heat treated.

[0079] Heat treatment is recommended for high value applications where particular value is placed on dimensional stability.

[0080] Heat treatment processes are known to those skilled in the art, in which the component is slowly and steadily heated below its melting or glass transition temperature for a period of minutes to hours depending on the type and thickness of the material.

[0081] Heat treatment is typically carried out at a temperature in the range of 0 to 200° C., preferably 15 to 170° C., more preferably 80 to 150° C. The application of elevated temperatures, and optionally negative pressure (vacuum), can facilitate the outward diffusion of any residual propellant or residual moisture.

[0082] Recycling-optimized single-material particle-foam components In a further aspect, the present invention relates to foams produced by the process of the present invention, mono-material particle-foam components, which are particularly well suited to recycling processes. Surprisingly, it has been found that components are obtained that can be sent for high-value recycling.

[0083] The avoidance of foreign material in the recycle makes single component particle-foam components particularly suitable for high value single product recycling.

[0084] The resulting single-component particle-foam components are generally closed-cell. They preferably have a viscosity of 20 to 250 kg / m, measured according to DIN EN ISO 1183-1 (Publication 2019-09). 3 range, more preferably 40 to 150 kg / m 3 It has a density in the range of

[0085] By combining the modified base polymer, used in its unfoamed form, with a corresponding foamed polymer derived from the same thermoplastic base material, a single-component particle-foam component is produced. This single-component system is suitable for upcycling because it is not mixed with foreign materials, thus avoiding the degradation of properties that would normally lead to downcycling. The modification of the base polymer is reversible, since with proper process control, the agent used for the modification in process step b) is removed, leaving little residue. This means that the thermomechanical properties and glass transition temperature of the base polymer can be almost fully achieved again.

[0086] Furthermore, it has been found that the modifications make it possible to reduce the processing temperature in process step d), which results in energy cost savings and therefore a more profitable process.

[0087] The use of the mono-material particle-foam components produced by the process according to one of the claims is wide-ranging: in particular, the process is used in the aerospace industry, shipbuilding, wind power, sports and leisure sectors, and in vehicle construction, in particular electric vehicles.

[0088] For example, it is preferred to use mono-material particle-foam components in lightweight constructions for the production of automotive parts such as sun visors, column cladding, headliners, luggage compartment and spare wheel covers, engine hoods, underbodies or parcel shelves, etc. Further common examples are semi-finished products for the production of furniture (e.g. panels) and the furniture itself, toys, outdoor objects, cladding and components for machines, etc.

[0089] The process and the single-material particle-foam components produced therewith are particularly suitable for high temperature applications. [Example]

[0090] [Example 1] Production of mono-material particle-foam components based on polyetherimide (PEI) First, a foamable polyetherimide (base polymer) is prepared.

[0091] A pre-foamed polyetherimide was used.

[0092] In a second process step, a modified polyetherimide (modified base polymer) is provided by placing a polyetherimide mold in the form of a screw boss having a glass transition temperature of 217°C as measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07) in an acetone bath heated to 50°C.

[0093] After 30 minutes, the surface of the polyetherimide screw boss was modified by acetone absorption, and the surface had a glass transition temperature (Tg) of 150°C. 改変されたベースポリマー It has.

[0094] The modified screw boss (modified base polymer) is inserted into a molding tool.

[0095] The mold tool is then closed and filled with the pre-expanded expandable polyetherimide (base polymer). A processing temperature (TP) of 175°C is set via the mold tool's jacket heating. Further energy application creates a material bond between the expanded polyetherimide and the polyetherimide screw boss.

[0096] The resulting polyetherimide-based single material particle-foam component was removed from the molding tool.

[0097] The single material particle-foam component had a solid material bond between the insert (screw boss) and the polyetherimide foam. [Example 2] Recycle-optimized single-material particle-foam component production A single-component particle foam mold made from the polyetherimide produced in Example 1 was heat-treated at 150°C for 24 hours. The agent (acetone) used for modification in Example 1 was almost completely removed. The residual acetone content was below the detection limit. The glass transition temperature of the recycle-optimized single-material particle-foam component was 217°C, as measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07).

Claims

1. A process for producing a mono-material particle-foam component based on a thermoplastic base polymer, characterized in that an expandable base polymer is processed into a mono-material particle-foam component together with a modified base polymer, A process wherein the modification of said thermoplastic base polymer to produce a modified base polymer is effected by the addition of a solvent, a blowing agent, or a plasticizer.

2. 2. The process of claim 1, a) providing an expandable base polymer, which may optionally already be pre-expanded; b) providing a modified base polymer; c) feeding the modified base polymer to the processing operation; and providing said expandable base polymer, optionally already pre-expanded; d) setting the processing temperature TP by supplying energy; and e) creating a material bond between the foamed base polymer and the modified base polymer; f) removing the resulting single material particle-foam component; g) optionally, heat treating the resulting single-component particle-foam component. A process comprising:

3. The modified base polymer has a glass transition temperature Tg of the base polymer, measured by DSC according to DIN EN ISO 11357-2 (Publication: 2014-07). ベースポリマー Glass transition temperature Tg 改変されたベースポリマー 2. The process of claim 1, comprising:

4. 2. The process according to claim 1, characterized in that the thermoplastic base polymer is selected from the group consisting of polyimides, polyketones and polyacrylates, preferably polymethacrylimide (PMI), polyetheretherketone (PEEK), polyetherimide (PEI), polymethyl(meth)acrylate (PM(M)A), polyethylene terephthalate (PET), polysulfone (PSU), polyethersulfone (PESU), polyphenylenesulfone (PPSU), polyamide (PA) or mixtures thereof.

5. 2. The process of claim 1, wherein the solvent is a blowing agent selected from the group consisting of ketones, non-halogenated hydrocarbons, alcohols, urea, acetone, pentane, methyl ethyl ketone, and methanol.

6. 10. The process of claim 1, wherein the modification of the thermoplastic base polymer to produce a modified base polymer is performed by spraying, dipping, wetting, or mixing with a blowing agent, solvent, or plasticizer.

7. 3. The process of claim 2, wherein in process step d), the processing temperature TP is above the glass transition temperature Tg of the expandable base polymer.

8. In process step e), the processing temperature TP is adjusted to the glass transition temperature Tg of the modified base polymer. 改変されたベースポリマー The process according to claim 2, characterized in that

9. 3. The process according to claim 2, characterized in that in process step c) the filling of the expandable base polymer takes place through injection points in the mold after the mold has been closed.

10. Use of single-material particle-foam components produced by the process according to claims 1 to 9 in the aerospace industry, shipbuilding, wind power, sports and leisure sectors and in vehicle construction, in particular electric vehicles.

11. 10. A recycle-optimized single-material particle-foam component produced by the process of claims 1 to 9, wherein the single-material particle-foam component comprises a thermoplastic base polymer and an agent used for modification, and the agent is removed leaving little or no residue.

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