WO2004003063A1 - Thermoplastic foamed materials comprising nanostructured filling materials and method for producing the same - Google Patents
Thermoplastic foamed materials comprising nanostructured filling materials and method for producing the same Download PDFInfo
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- WO2004003063A1 WO2004003063A1 PCT/EP2003/006941 EP0306941W WO2004003063A1 WO 2004003063 A1 WO2004003063 A1 WO 2004003063A1 EP 0306941 W EP0306941 W EP 0306941W WO 2004003063 A1 WO2004003063 A1 WO 2004003063A1
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- the invention relates to physically expanded thermoplastic foams made of a polymer matrix and the fine fillers 5 embedded therein and having a density between 8 and 350 g / l, and to a process for their production in which a thermoplastic polymer in the form of granules is fed to an extruder together with fine fillers and extruded to form a polymer compound, the compound being foamed simultaneously or thereafter by means of physical blowing agents and being extruded into foam particles, a foam sheet or a foam sheet.
- polyolefin foam particles are produced in an autoclave or extrusion process.
- spherical, closed-cell foam particles with a diameter are usually made from microgranules in a pressure vessel with the addition of blowing agents
- the polymer is expanded into the polymer melt at the nozzle outlet by adding physical blowing agents and chopped off to form almost spherical or cylindrical foam particles.
- the molded parts are produced from the foam particles in the molded part process by welding using superheated steam. Furthermore are
- 25 15 - 150 g / 1 is achieved through their constructive design, the choice of material density or the combination with fillers, cover layers or inserts. Another possibility is to form a composite by foaming, foaming or subsequently laminating the foam parts. From DE-A-43 12 517 and DE-A-195 44 451 the combination of a foam part with a reinforcing mat, a fabric or a fleece is known to reduce the crack sensitivity of the molded part.
- EP-A-1 077 127 a composite material based on a natural fiber mat is known which is interspersed with foamable and / or curable substances.
- rod-shaped elements are integrated into the molded foam part in order to improve the energy absorption, so as to optimize the rigidity and the energy absorption capacity depending on the application.
- DE-A-33 45 408 and DE-A-44 32 082 describe molded parts made of foam elements of different densities, the properties of which can be changed depending on the density.
- nanoparticles that is to say particles with an average particle size in the nanometer range
- WO 01/96459 describes the improvement of the connection of nanoparticles to polymers by using modified layered silicates for the production of nano-reinforced thermoplastics and molded parts.
- DE-A-198 15 632 describes the production of molded polymer parts with hollow structures contained therein in the form of nano-channels.
- the invention has for its object to provide physically expanded thermoplastic foams with low density and a method for their preparation, which are simple and inexpensive to manufacture without the fillers damage the cell walls and thus the foam structure and thus can impair the mechanical strength.
- thermoplastic foams of the type mentioned at the outset in that the foams contain 0.001-40% by mass of nanoparticles as fillers.
- the nanoparticles of the foams according to the invention are embedded in the cell walls without the cell walls being damaged in the process.
- the material properties of the foams according to the invention can be influenced in a targeted manner as a result of the interface interactions that occur. Since the average particle size of the nanoparticles is smaller than the thickness of the cell walls of the foam, the effect of interface effects is increased. Due to the small particle sizes, a large inner surface is introduced into the polymer, which means that the finely divided filler phase and its interface properties are effective even at low fill levels.
- nano-reinforced or nano-filled foams with specific properties for example improved mechanical, optical, antibiotic, dirt-repellent or flame-retardant properties, can be produced.
- Nanostructured fillers are preferably used as nanoparticles. This includes nanoparticles that have a special external shape, such as nanofibers, nanoigels, nanotubes, but also layers of nanoparticles and such nanoparticles, the surface of which is caused by elevations or depressions, scars, pores or special structural features such as one Lotus leaf-shaped surface is modified.
- the nanoparticles are completely or partially coated, for example with salts, ions or other charged or uncharged particles, in order to specifically change their surface-active properties.
- the nanoparticles are preferably selected from the group of pigments, carbon blacks, graphites, ceramic materials such as zinc oxide, titanium dioxide, aluminum oxide, aluminum hydroxide, mica, silicates, clays, clays and their addition compounds, in particular hydrates.
- Ceramic nanoparticles can also be used.
- the nanoparticles can consist of a single one of the materials mentioned, but nanoparticles based on different materials can also be used.
- inorganic nanostructured fillers in particular form reinforcement networks in an organic polymer matrix. By orienting them within the cell walls, the nanostructured fillers can form two-dimensional networks and thus improve the mechanical properties of the foams according to the invention, in particular their tear strength. This is not possible with the known high-density foams, as described in the prior art cited at the outset, because the cell walls there are significantly thicker. One reason for this is the gas bubble deposits that occur in the usual thermoplastic foam casting process. Nanostructured fillers can also nucleate foam formation and / or crystallization and initiate nano-cellular foams. Nanoparticles with flame-retardant properties, with UV-absorbing properties, with antibiotic properties and / or with dirt-repellent properties are particularly preferably used.
- the crystal structure in the grains of nanocrystalline solids and in nanoparticles also relaxes near interfaces or surfaces.
- these effects play a decisive role, unlike with coarse-crystalline materials.
- nanocarbon fibers or nanotubes improve the mechanical properties even at low fill levels.
- Fillers such as aluminum hydroxide or synthetic mica are more flame-retardant in the form of nanoparticles than with conventional grains.
- Zinc oxide nanoparticles protect against UV radiation and soot increases the life of the foams.
- Foam are negatively affected, as a bursting of the cell walls is avoided during foam formation.
- the nanoparticles have surfaces of a few hundred m Ig. These properties can also be used to improve the coloring of the foams.
- the nanoparticles can be modified with an adhesion promoter to improve the adhesion between the filler particles and the polymer matrix.
- An adhesion promoter can also be added to the mixture of polymer granules and nanoparticles. Surfactants, silanes or anhydrides such as maleic anhydride are preferred as adhesion promoters.
- Polyolefins or mixtures of polyolefins are preferably used as the polymer matrix, particularly preferably polypropylene and / or polyethylene.
- the process according to the invention of the type mentioned at the outset is characterized in that nanoparticles are used as fillers in an amount of 0.001-40 Mass percent are used, fillers and polymer granules are preferably premixed.
- the incorporation of the nanoparticles into the polymer melt formed in the extruder can be carried out using various methods, for example in a single-shaft, two-shaft or planetary roller extruder, but also in a kneader.
- the mixing and adjustment of the filler components can first be achieved by manual premixing or by direct addition of the nanoparticles in the processing process. Due to the small particle sizes, the particles are not damaged by shear stress during compounding and the subsequent processes for further processing and formation of the foam structure.
- the compound of polymer matrix and nanoparticles can then first be granulated or extruded directly into foams in the form of foils, sheets or profiles.
- the nanoparticles can be further processed by adding physical blowing agents directly to foams such as foamed semi-finished products, preferably XPP (polypropylene foam films), molded parts or foam particles, preferably EPP (expanded polypropylene particle foam), EPS (expanded polystyrene) or EPE (expanded polyethylene particle foam).
- foamed semi-finished products preferably XPP (polypropylene foam films), molded parts or foam particles, preferably EPP (expanded polypropylene particle foam), EPS (expanded polystyrene) or EPE (expanded polyethylene particle foam).
- the directly foamed products are manufactured in the extrusion process using appropriate shaping tools.
- One variant is the production of microgranules from the polymer compound and the foaming of the granules to form foam particles in the autoclave process, which are welded to superheated steam in the subsequent molding process.
- Another variant is the foaming of the compound in the extrusion process by adding physical blowing agents. The polymer melt expanding at the nozzle outlet is chopped off directly to foam particles.
- Foam molded parts are also produced in the molded part process by means of welding using superheated steam.
- Another variant is the direct foaming of semi-finished or molded parts in extrusion sion process by using physical blowing agents and an appropriate extrusion tool.
- An unwanted agglomeration of the nanoparticles during processing is prevented or at least strongly suppressed by suitable coating of the particles.
- Polypropylene granules and a nanostructured filler made of alumina (aluminum oxide) and / or layered silicate (montmorillonite) are fed to an extruder via metering devices.
- the filler particles are finely dispersed in the polymer matrix. Foaming of the polymer compound is achieved online or in a second extrusion process by adding physical blowing agents.
- the polymer melt expanding at the nozzle outlet is knocked off into foam particles by means of rotating knives.
- the filler particles are distributed in the cell walls of the foam particles.
- moldings are produced in a conventional manner by welding the foam particles (beads) using superheated steam.
- Example 1 a polymer compound made from polypropylene granules and nanostructured fillers is extruded and foamed. At a flat slot nozzle or an annular nozzle, the polymer melt expands to a foam plate or a foam sheet due to the pressure drop. The plates or foils can then be further processed into molded parts in a thermoforming process.
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Abstract
Description
THERMOPLASTISCHE SCHAUMSTOFFE MIT NANOSTRUKTURIERTEN FÜLLSTOFFEN UND VERFAHREN ZU IHRER HERSTELLUNGTHERMOPLASTIC FOAMS WITH NANOSTRUCTURED FILLERS AND METHOD FOR THEIR PRODUCTION
Die Erfindung betrifft physikalisch expandierte thermoplastische Schaumstoffe aus einer Polymermatrix und darin eingelagerten feinteihgen Füllstoffen 5 und mit einer Dichte zwischen 8 und 350 g/1 sowie ein Verfahren zu ihrer Herstellung, bei dem ein thermoplastisches Polymer in Form eines Granulats zusammen mit feinteihgen Füllstoffen einem Extruder zugeführt und zu einem Polymer-Compound extrudiert werden, wobei das Compound gleichzeitig oder danach mittels physikalischer Treibmittel aufgeschäumt und zu Schaumpartikeln, 10 einer Schaumplatte oder einer Schaumfolie extrudiert wird.The invention relates to physically expanded thermoplastic foams made of a polymer matrix and the fine fillers 5 embedded therein and having a density between 8 and 350 g / l, and to a process for their production in which a thermoplastic polymer in the form of granules is fed to an extruder together with fine fillers and extruded to form a polymer compound, the compound being foamed simultaneously or thereafter by means of physical blowing agents and being extruded into foam particles, a foam sheet or a foam sheet.
Es ist bekannt, daß Polyolefin-Schaumstoffpartikel im Autoklav- oder Extrusionsverfahren hergestellt werden. Beim Autoklawerfahren werden in einem Druckbehälter aus Mikrogranulat und unter Zugabe von Treibmitteln zumeist sphärische, geschlossenzellige Schaumpartikel mit einem DurchmesserIt is known that polyolefin foam particles are produced in an autoclave or extrusion process. In the autoclave process, spherical, closed-cell foam particles with a diameter are usually made from microgranules in a pressure vessel with the addition of blowing agents
15 von etwa 2 - 10 mm hergestellt. Im Extrusionsverfahren wird das Polymer über Zugabe physikalischer Treibmittel in die Polymerschmelze am Düsenausgang expandiert und zu nahezu sphärischen oder zylindrischen Schaumpartikeln abgeschlagen. Die Formteilherstellung aus den Schaumpartikeln erfolgt im Formteilprozeß über die Verschweißung mittels Heißdampf. Ferner sind15 made of about 2 - 10 mm. In the extrusion process, the polymer is expanded into the polymer melt at the nozzle outlet by adding physical blowing agents and chopped off to form almost spherical or cylindrical foam particles. The molded parts are produced from the foam particles in the molded part process by welding using superheated steam. Furthermore are
20 Verfahren bekannt, bei denen Halbzeuge oder Formteile aus Polyolefinschaum- stoffen direkt im Extrusions- oder Spritzgießverfahren durch Zugabe chemischer und/oder physikalischer Treibmittel hergestellt werden. Die Modifizierung der Eigenschaften von Formteilen aus Partikelschaumstoffen oder von direkt geschäumten Formteilen, die in der Regel weichelastisch sind und eine Dichte von20 processes are known in which semi-finished products or molded parts made of polyolefin foams are produced directly in the extrusion or injection molding process by adding chemical and / or physical blowing agents. The modification of the properties of molded parts made of particle foams or of directly foamed molded parts, which are generally flexible and have a density of
25 15 - 150 g/1 aufweisen, wird durch ihre konstruktive Auslegung, die Wahl der Materialdichte oder die Kombination mit Füllstoffen, Deckschichten oder Einlegeteilen erreicht. Eine weitere Möglichkeit besteht in der Bildung eines Werkstoffverbundes durch Umschäumen, Hinterschäumen oder nachträgliches Kaschieren der Schaumstoffteile. Aus DE-A-43 12 517 und DE-A-195 44 451 ist die Kombination eines Schaumstoffteils mit einer Verstärkungsmatte, einem Gewebe oder einem Vlies zum Herabsetzen der Rißempfindlichkeit des Formteils bekannt.25 15 - 150 g / 1, is achieved through their constructive design, the choice of material density or the combination with fillers, cover layers or inserts. Another possibility is to form a composite by foaming, foaming or subsequently laminating the foam parts. From DE-A-43 12 517 and DE-A-195 44 451 the combination of a foam part with a reinforcing mat, a fabric or a fleece is known to reduce the crack sensitivity of the molded part.
Aus EP-A-1 077 127 ist ein Verbundwerkstoff auf Basis einer Naturfasermatte bekannt, die mit schäumbaren und/oder härtbaren Stoffen durchsetzt ist.From EP-A-1 077 127 a composite material based on a natural fiber mat is known which is interspersed with foamable and / or curable substances.
Gemäß DE- A- 196 41 944 werden zur Verbesserung der Energieabsorption stäbchenförmige Elemente in das Schaumformteil integriert, um so die Steifigkeit und das Energieabsorptionsvermögen je nach Anwendungsfall zu optimieren.According to DE-A-196 41 944, rod-shaped elements are integrated into the molded foam part in order to improve the energy absorption, so as to optimize the rigidity and the energy absorption capacity depending on the application.
In DE-A-33 45 408 und DE-A-44 32 082 sind Formteile aus Schaum- elementen verschiedener Dichte beschrieben, deren Eigenschaften in Abhängigkeit von der Dichte verändert werden können.DE-A-33 45 408 and DE-A-44 32 082 describe molded parts made of foam elements of different densities, the properties of which can be changed depending on the density.
Der Einsatz von Nanopartikeln, also Teilchen mit einer mittleren Teilchengröße im Nanometerbereich, zur Verstärkung von Schaumstoffen wird in WO 00/37242 beschrieben, wobei von direkt geschäumten sprödharten Schaum- stof -Formteilen mit Dichten von mehr als 320 g/1 ausgegangen wird. Die Verbesserung der Anbindung von Nanopartikeln an Polymere durch Einsatz modifizierter Schichtsilikate zur Herstellung nanoverstärkter Thermoplaste und Formteile wird in WO 01/96459 beschrieben. Zur Modifizierung der Eigenschaften polymerer Bauteile wird in DE-A-198 15 632 die Herstellung von Polymerformteilen mit darin enthaltenen Hohlstrukturen in Form von Nano- kanälen beschrieben.The use of nanoparticles, that is to say particles with an average particle size in the nanometer range, for reinforcing foams is described in WO 00/37242, starting from directly foamed, brittle, hard foam molded parts with densities of more than 320 g / l. WO 01/96459 describes the improvement of the connection of nanoparticles to polymers by using modified layered silicates for the production of nano-reinforced thermoplastics and molded parts. To modify the properties of polymeric components, DE-A-198 15 632 describes the production of molded polymer parts with hollow structures contained therein in the form of nano-channels.
Die Herstellung von Leichtschaumstofformteilen mit gezielter Abstimmung auf gewünschte Anforderungen wie erhöhte Festigkeit, bessere Wärmeformbeständigkeit oder Modifizierungen zur Verbesserung der flammhemmenden Wirkung erfordern meist weitere Prozeßschritte, wie die Zugabe von Additiven und Hilfsstoffen, die Kaschierung mit Deckschichten oder das Umschäumen von Einlegeteilen, was mit erheblichen Kosten und Aufwand verbunden ist. Weitere Nachteile sind die Instabilität des Herstellungsverfahrens sowie eine häufig unzureichende Haftung der Komponenten des Werkstoffverbundes. Der Einsatz von Zusatzstoffen wie Verstärkungsfasern im Millimeter- oder Mikrometerbereich ist mit einer Schädigung der Zellwände und einem unerwünschten Eindringen der Fasern in die Schaumstruktur verbunden. Der Einsatz von Additiven, beispielsweise Flammschutzmitteln, kann ebenfalls eine Beeinträchtigung der Schaum- Struktur und der mechanischen Eigenschaften des Verbundes zur Folge haben.The production of lightweight foam molded parts with targeted adjustment to desired requirements such as increased strength, better heat resistance or modifications to improve the flame-retardant effect usually require further process steps, such as the addition of additives and auxiliaries, the lamination with cover layers or the foaming of inserts, which involves considerable costs and effort is connected. Other disadvantages are the instability of the manufacturing process and the often insufficient adhesion of the components of the composite material. The stake Additives such as reinforcing fibers in the millimeter or micrometer range are associated with damage to the cell walls and undesired penetration of the fibers into the foam structure. The use of additives, for example flame retardants, can also impair the foam structure and the mechanical properties of the composite.
Der Erfindung liegt die Aufgabe zugrunde, physikalisch expandierte thermoplastische Schaumstoffe mit niedriger Dichte sowie ein Verfahren zu ihrer Herstellung bereitzustellen, die einfach und kostengünstig herstellbar sind, ohne daß die Füllstoffe die Zellwände und damit die Schaumstruktur schädigen und damit die mechanische Festigkeit beeinträchtigen können.The invention has for its object to provide physically expanded thermoplastic foams with low density and a method for their preparation, which are simple and inexpensive to manufacture without the fillers damage the cell walls and thus the foam structure and thus can impair the mechanical strength.
Diese Aufgabe wird erfindungsgemäß bei physikalisch expandierten thermoplastischen Schaumstoffen der eingangs genannten Gattung dadurch gelöst, daß die Schaumstoffe 0,001 - 40 Masseprozent Nanopartikel als Füllstoffe enthalten.This object is achieved according to the invention in the case of physically expanded thermoplastic foams of the type mentioned at the outset in that the foams contain 0.001-40% by mass of nanoparticles as fillers.
Die Nanopartikel der erfindungsgemäßen Schaumstoffe werden in den Zellwänden eingelagert, ohne daß dabei die Zellwände geschädigt würden. Dadurch können die Werkstoffeigenschaften der erfindungsgemäßen Schaumstoffe infolge der auftretenden Grenzflächeninteraktionen gezielt beeinflußt werden. Da die mittlere Teilchengröße der Nanopartikel kleiner ist als die Dicke der Zellwände des Schaumstoffs, wird die Wirkung von Grenzflächeneffekten verstärkt. Aufgrund der kleinen Teilchengrößen wird eine große innere Oberfläche in das Polymer eingebracht, wodurch die feinverteilte Füllstoffphase und deren Grenzflächeneigenschaften schon bei geringen Füllgraden Wirkung zeigen. Hierdurch können nanoverstärkte bzw. nanogefüllte Schaumstoffe mit gezielten Eigenschaften, beispielsweise verbesserten mechanischen, optischen, antibio- tischen, schmutzabweisenden oder flammhemmenden Eigenschaften hergestellt werden. Die flammhemmende Wirkung beispielsweise wird durch die deutlich größere Oberfläche der Nanopartikel mit flammhemmenden Eigenschaften im Vergleich zu üblichen Partikelgrößen deutlich erhöht. Als Nanopartikel werden vorzugsweise nanostrukturierte Füllstoffe verwendet. Hierunter sind Nanopartikel zu verstehen, die eine besondere äußere Form besitzen, wie z.B. Nanofasern, Nanoigel, Nanoröhrchen (Nanotubes), aber auch Schichtungen von Nanopartikeln und solche Nanopartikel, deren Oberfläche durch Erhöhungen oder Vertiefungen, Narben, Poren oder besondere Strukturmerkmale, wie z.B. eine Lotusblatt-förmige Oberfläche, modifiziert ist.The nanoparticles of the foams according to the invention are embedded in the cell walls without the cell walls being damaged in the process. As a result, the material properties of the foams according to the invention can be influenced in a targeted manner as a result of the interface interactions that occur. Since the average particle size of the nanoparticles is smaller than the thickness of the cell walls of the foam, the effect of interface effects is increased. Due to the small particle sizes, a large inner surface is introduced into the polymer, which means that the finely divided filler phase and its interface properties are effective even at low fill levels. As a result, nano-reinforced or nano-filled foams with specific properties, for example improved mechanical, optical, antibiotic, dirt-repellent or flame-retardant properties, can be produced. The flame-retardant effect, for example, is significantly increased by the significantly larger surface area of the nanoparticles with flame-retardant properties compared to conventional particle sizes. Nanostructured fillers are preferably used as nanoparticles. This includes nanoparticles that have a special external shape, such as nanofibers, nanoigels, nanotubes, but also layers of nanoparticles and such nanoparticles, the surface of which is caused by elevations or depressions, scars, pores or special structural features such as one Lotus leaf-shaped surface is modified.
Bei einer weiteren bevorzugten Ausführungsform der Erfindung sind die Nanopartikel ganz oder teilweise beschichtet, beispielsweise mit Salzen, Ionen oder anderen geladenen oder ungeladenen Teilchen, um ihre oberflächenaktiven Eigenschaften gezielt zu verändern.In a further preferred embodiment of the invention, the nanoparticles are completely or partially coated, for example with salts, ions or other charged or uncharged particles, in order to specifically change their surface-active properties.
Die Nanopartikel sind vorzugsweise ausgewählt aus der Gruppe der Pigmente, Ruße, Graphite, keramischen Materialien wie Zinkoxid, Titandioxid, Aluminiumoxid, Aluminiumhydroxid, Glimmer, Silikate, Tone, Tonerden und deren Additionsverbindungen, insbesondere Hydraten. Auch metallische Nanopartikel können eingesetzt werden. Die Nanopartikel können aus einem einzigen der genannten Materialien bestehen, aber es können auch Nanopartikel auf Basis unterschiedlicher Materialien eingesetzt werden.The nanoparticles are preferably selected from the group of pigments, carbon blacks, graphites, ceramic materials such as zinc oxide, titanium dioxide, aluminum oxide, aluminum hydroxide, mica, silicates, clays, clays and their addition compounds, in particular hydrates. Metallic nanoparticles can also be used. The nanoparticles can consist of a single one of the materials mentioned, but nanoparticles based on different materials can also be used.
Durch zusätzliche Grenzflächeneffekte bilden insbesondere anorganische nanostrukturierte Füllstoffe in einer organischen Polymermatrix Verstärkungs- netzwerke aus. Die nanostrukturierten Füllstoffe können durch Orientierung innerhalb der Zellwände zweidimensionale Netzwerke bilden und so die mechanischen Eigenschaften der erfindungsgemäßen Schaumstoffe, insbesondere deren Reißfestigkeit, verbessern. Dies ist bei den bekannten Schaumstoffen hoher Dichte, wie sie in dem eingangs zitierten Stand der Technik beschrieben sind, nicht möglich, weil die Zellwände dort deutlich dicker sind. Ein Grund dafür sind die Gasblaseneinlagerungen, die bei dem üblichen Thermoplastschaumguß- verfahren entstehen. Nanostrukturierte Füllstoffe können auch die Nukleierung der Schaumbildung und/oder der Kristallisation bewirken und nanozelluläre Schaumstoffe initiieren. Besonders bevorzugt werden Nanopartikel mit flammhemmenden Eigenschaften, mit UV-absorbierenden Eigenschaften, mit antibiotischen Eigenschaften und/oder mit schmutzabweisenden Eigenschaften eingesetzt.Due to additional interface effects, inorganic nanostructured fillers in particular form reinforcement networks in an organic polymer matrix. By orienting them within the cell walls, the nanostructured fillers can form two-dimensional networks and thus improve the mechanical properties of the foams according to the invention, in particular their tear strength. This is not possible with the known high-density foams, as described in the prior art cited at the outset, because the cell walls there are significantly thicker. One reason for this is the gas bubble deposits that occur in the usual thermoplastic foam casting process. Nanostructured fillers can also nucleate foam formation and / or crystallization and initiate nano-cellular foams. Nanoparticles with flame-retardant properties, with UV-absorbing properties, with antibiotic properties and / or with dirt-repellent properties are particularly preferably used.
Wie in allen Festkörpern, relaxiert auch in den Körnern nanokristalliner Feststoffe und in Nanopartikeln die Kristallstruktur in der Nähe von Grenzflächen bzw. Oberflächen. Bei nanokristallinen Materialien mit großen Volumanteilen der grenzflächennahen Bereiche spielen diese Effekte, anders als bei grobkristallinen Stoffen, eine entscheidende Rolle. Beispielsweise bewirken Nanocarbonfasern oder Nanotubes eine Verbesserung der mechanischen Eigenschaften schon bei geringen Füllgraden. Füllstoffe wie Aluminiumhydroxid oder synthetischer Glimmer sind in Form von Nanopartikeln flammhemmender als bei üblichen Körnungen. Nanopartikel aus Zinkoxid schützen vor UV-Strahlung und Ruß erhöht die Lebensdauer der Schaumstoffe.As in all solids, the crystal structure in the grains of nanocrystalline solids and in nanoparticles also relaxes near interfaces or surfaces. In the case of nanocrystalline materials with large volumes of the areas close to the interface, these effects play a decisive role, unlike with coarse-crystalline materials. For example, nanocarbon fibers or nanotubes improve the mechanical properties even at low fill levels. Fillers such as aluminum hydroxide or synthetic mica are more flame-retardant in the form of nanoparticles than with conventional grains. Zinc oxide nanoparticles protect against UV radiation and soot increases the life of the foams.
Mittels nanostrukturierter Füllstoffe können höhere Füllgrade realisiert werden, ohne daß durch die Füllstoffe die mechanischen Eigenschaften desBy means of nanostructured fillers, higher degrees of filling can be achieved without the mechanical properties of the
Schaumstoffes negativ beeinflußt werden, da ein Aufplatzen der Zellwände während der Schaumbildung vermieden wird. Der Einsatz von nanostrukturiertenFoam are negatively affected, as a bursting of the cell walls is avoided during foam formation. The use of nanostructured
Füllstoffen führt somit zu einer deutlich geschlossenzelligeren Struktur.Fillers thus lead to a significantly more closed-cell structure.
Die Nanopartikel besitzen Oberflächen von einigen Hundert m Ig. Diese Eigenschaften können auch zur Verbesserung der Farbgebung der Schaumstoffe ausgenutzt werden. Zusätzlich können die Nanopartikel mit einem Haftvermittler modifiziert werden, um die Haftung zwischen den Füllstoffteilchen und der Polymermatrix zu verbessern. Ein Haftvermittler kann auch dem Gemisch aus Polymergranulat und Nanopartikeln zugegeben werden. Als Haftvermittler werden Tenside, Silane oder Anhydride wie Maleinsäureanhydrid bevorzugt.The nanoparticles have surfaces of a few hundred m Ig. These properties can also be used to improve the coloring of the foams. In addition, the nanoparticles can be modified with an adhesion promoter to improve the adhesion between the filler particles and the polymer matrix. An adhesion promoter can also be added to the mixture of polymer granules and nanoparticles. Surfactants, silanes or anhydrides such as maleic anhydride are preferred as adhesion promoters.
Als Polymermatrix werden vorzugsweise Polyolefine oder Gemische von Polyolefinen verwendet, besonders bevorzugt Polypropylen und/oder Polyethylen.Polyolefins or mixtures of polyolefins are preferably used as the polymer matrix, particularly preferably polypropylene and / or polyethylene.
Das erfindungsgemäße Verfahren der eingangs genannten Gattung ist dadurch gekennzeichnet, daß als Füllstoffe Nanopartikel in einer Menge von 0,001 - 40 Masseprozent verwendet werden, wobei Füllstoffe und Polymergranulat vorzugsweise vorgemischt werden.The process according to the invention of the type mentioned at the outset is characterized in that nanoparticles are used as fillers in an amount of 0.001-40 Mass percent are used, fillers and polymer granules are preferably premixed.
Die Einarbeitung der Nanopartikel in die im Extruder gebildete Polymerschmelze kann über verschiedene Verfahren, beispielsweise in einem Einwellen-, Zweiwellen- oder Planetwalzenextruder, aber auch in einem Kneter, erfolgen. Die Mischung und Einstellung der Füllstoffanteile kann zunächst über manuelles Vormischen oder über eine direkte Zudosierung der Nanopartikel im Verarbeitungsprozeß erreicht werden. Aufgrund der kleinen Teilchengrößen erfolgt keine Schädigung der Teilchen durch Scherbeanspruchung beim Compoundieren und den anschließenden Prozessen zur Weiterverarbeitung und Ausbildung der Schaumstruktur. Das Compound aus Polymermatrix und Nanopartikeln kann dann zunächst granuliert oder direkt zu Schaumstoffen in Form von Folien, Platten oder Profilen extrudiert werden.The incorporation of the nanoparticles into the polymer melt formed in the extruder can be carried out using various methods, for example in a single-shaft, two-shaft or planetary roller extruder, but also in a kneader. The mixing and adjustment of the filler components can first be achieved by manual premixing or by direct addition of the nanoparticles in the processing process. Due to the small particle sizes, the particles are not damaged by shear stress during compounding and the subsequent processes for further processing and formation of the foam structure. The compound of polymer matrix and nanoparticles can then first be granulated or extruded directly into foams in the form of foils, sheets or profiles.
Die Nanopartikel können durch direkte Zugabe physikalischer Treibmittel zu Schaumstoffen wie geschäumten Halbzeugen, vorzugsweise XPP (Polypropylenschaumfolien), Formteilen oder Schaumstoffpartikel, vorzugsweise EPP (expandierter Polypropylenpartikelschaum), EPS (expandiertes Polystyrol) oder EPE (expandierter Polyethylenpartikelschaum) weiterverarbeitet werden. Die Herstellung der direkt geschäumten Produkte erfolgt im Extrusionsprozeß unter Einsatz entsprechend formgebender Werkzeuge.The nanoparticles can be further processed by adding physical blowing agents directly to foams such as foamed semi-finished products, preferably XPP (polypropylene foam films), molded parts or foam particles, preferably EPP (expanded polypropylene particle foam), EPS (expanded polystyrene) or EPE (expanded polyethylene particle foam). The directly foamed products are manufactured in the extrusion process using appropriate shaping tools.
Eine Variante ist die Herstellung von Mikrogranulat aus dem Polymer- compound und das Aufschäumen der Granulatkörner zu Schaumstoffpartikeln im Autoklavprozeß, die im anschließenden Formteilprozeß mit Heißdampf zu Formteilen verschweißt werden. Eine andere Variante ist das Aufschäumen des Compounds im Extrusionsverfahren durch Zugabe physikalischer Treibmittel. Die am Düsenausgang expandierende Polymerschmelze wird direkt zu Schaumpartikeln abgeschlagen. Die Fertigung von Schaumstofformteilen erfolgt ebenfalls im Formteilprozeß über die Verschweißung mittels Heißdampf. Eine weitere Variante ist das Direktschäumen von Halbzeugen oder Formteilen im Extru- sionsprozeß durch Einsatz physikalischer Treibmittel und über ein entsprechendes Extrusionswerkzeug.One variant is the production of microgranules from the polymer compound and the foaming of the granules to form foam particles in the autoclave process, which are welded to superheated steam in the subsequent molding process. Another variant is the foaming of the compound in the extrusion process by adding physical blowing agents. The polymer melt expanding at the nozzle outlet is chopped off directly to foam particles. Foam molded parts are also produced in the molded part process by means of welding using superheated steam. Another variant is the direct foaming of semi-finished or molded parts in extrusion sion process by using physical blowing agents and an appropriate extrusion tool.
Allen Varianten gemeinsam ist die Ausbildung einer Zellstruktur mit Zellwanddicken im Mikrometer- oder Nanometerbereich. Die feindisperse Verteilung der Nanopartikel in der Polymermatrix und die Tatsache, daß die Partikelgrößen der Nanopartikel kleiner sind als die Zellwanddicke der Schaumstoffe, bewirken eine gleichmäßige Verteilung der Nanopartikel in den Zellwänden, ohne daß Füllstoffpartikel in die Schaumzellen eindringen oder sich aus der Polymermatrix lösen. Auch bei geknickten Zellwänden, im Falle der Belastung der Schaumstoffe, ergeben sich keine Beeinträchtigungen.Common to all variants is the formation of a cell structure with cell wall thicknesses in the micrometer or nanometer range. The finely dispersed distribution of the nanoparticles in the polymer matrix and the fact that the particle sizes of the nanoparticles are smaller than the cell wall thickness of the foams result in a uniform distribution of the nanoparticles in the cell walls without filler particles penetrating into the foam cells or detaching from the polymer matrix. Even if the cell walls are kinked, if the foams are loaded, there are no impairments.
Eine unerwünschte Agglomeration der Nanopartikel während der Verarbeitung wird durch geeignete Beschichtung der Partikel verhindert oder mindestens stark unterdrückt.An unwanted agglomeration of the nanoparticles during processing is prevented or at least strongly suppressed by suitable coating of the particles.
Die Erfindung wird nachfolgend anhand der Beispiele weiter erläutert:The invention is explained in more detail below with the aid of the examples:
Beispiel 1example 1
Polypropylengranulat und ein nanostrukturierter Füllstoff aus Tonerde (Aluminiumoxid) und/oder Schichtsilikat (Montmorillonit) werden über Dosiereinrichtungen einem Extruder zugeführt. Im Extrusionsprozeß werden die Füllstoffpartikel feindispers in der Polymermatrix verteilt. Online oder in einem zweiten Extrusionsprozeß wird durch die Zugabe physikalischer Treibmittel ein Aufschäumen des Polymercompounds erreicht. Die am Düsenausgang expandierende Polymerschmelze wird mittels rotierender Messer zu Schaumpartikeln abgeschlagen. Die Füllstoffpartikel sind in den Zellwänden der Schaumstoffpartikel verteilt. In einem anschließenden Formteilprozeß werden auf herkömm- liehe Weise Formteile durch Verschweißung der Schaumstofφartikel (Beads) mittels Heißdampf hergestellt. Beispiel 2Polypropylene granules and a nanostructured filler made of alumina (aluminum oxide) and / or layered silicate (montmorillonite) are fed to an extruder via metering devices. In the extrusion process, the filler particles are finely dispersed in the polymer matrix. Foaming of the polymer compound is achieved online or in a second extrusion process by adding physical blowing agents. The polymer melt expanding at the nozzle outlet is knocked off into foam particles by means of rotating knives. The filler particles are distributed in the cell walls of the foam particles. In a subsequent molding process, moldings are produced in a conventional manner by welding the foam particles (beads) using superheated steam. Example 2
Wie in Beispiel 1 beschrieben, wird ein Polymercompound aus Polypropylengranulat und nanostrukturierten Füllstoffen extrudiert und aufgeschäumt. An einer Flachschlitzdüse oder einer Kreisringdüse expandiert die Polymerschmelze durch den Druckabfall zu einer Schaumplatte oder einer Schaumfolie. Die Platten oder Folien können anschließend in einem Thermoformierprozeß zu Formteilen weiterverarbeitet werden. As described in Example 1, a polymer compound made from polypropylene granules and nanostructured fillers is extruded and foamed. At a flat slot nozzle or an annular nozzle, the polymer melt expands to a foam plate or a foam sheet due to the pressure drop. The plates or foils can then be further processed into molded parts in a thermoforming process.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2003280166A AU2003280166A1 (en) | 2002-07-03 | 2003-06-30 | Thermoplastic foamed materials comprising nanostructured filling materials and method for producing the same |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2002129983 DE10229983A1 (en) | 2002-07-03 | 2002-07-03 | Thermoplastic foams with nanostructured fillers and process for their production |
| DE10229983.8 | 2002-07-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2004003063A1 true WO2004003063A1 (en) | 2004-01-08 |
| WO2004003063A8 WO2004003063A8 (en) | 2004-07-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2003/006941 Ceased WO2004003063A1 (en) | 2002-07-03 | 2003-06-30 | Thermoplastic foamed materials comprising nanostructured filling materials and method for producing the same |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2003280166A1 (en) |
| DE (1) | DE10229983A1 (en) |
| WO (1) | WO2004003063A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004004237C5 (en) * | 2004-01-27 | 2009-11-12 | Woco Industrietechnik Gmbh | Process for the production of microporous plastic products and the moldings, profiles and granules obtainable by this process |
| US9187608B2 (en) | 2005-09-08 | 2015-11-17 | Owens Corning Intellectual Capital, Llc | Polystyrene foam containing a modifier-free nanoclay and having improved fire protection performance |
| US10184037B2 (en) | 2003-11-26 | 2019-01-22 | Owens Corning Intellectual Capital, Llc | Thermoplastic foams and method of forming them using nano-graphite |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8568632B2 (en) * | 2003-11-26 | 2013-10-29 | Owens Corning Intellectual Capital, Llc | Method of forming thermoplastic foams using nano-particles to control cell morphology |
| DE102012208914A1 (en) * | 2012-05-25 | 2013-11-28 | Bombardier Transportation Gmbh | Seat for the interior of a public transport with a color-coordinated fabric layer |
| DE102015116606B4 (en) | 2015-09-30 | 2018-07-12 | Jörg Beckmann | Process for producing a plastic component and plastic component |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717000A (en) * | 1996-02-23 | 1998-02-10 | The Dow Chemical Company | Despersions of delaminated particles in polymer foams |
| WO2000037242A1 (en) * | 1998-12-21 | 2000-06-29 | Magna International Of America, Inc. | Structural foam composite having nano-particle reinforcement and method of making the same |
| WO2000047657A2 (en) * | 1999-02-12 | 2000-08-17 | The Dow Chemical Company | Nanocomposite articles and process for making |
-
2002
- 2002-07-03 DE DE2002129983 patent/DE10229983A1/en not_active Withdrawn
-
2003
- 2003-06-30 WO PCT/EP2003/006941 patent/WO2004003063A1/en not_active Ceased
- 2003-06-30 AU AU2003280166A patent/AU2003280166A1/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5717000A (en) * | 1996-02-23 | 1998-02-10 | The Dow Chemical Company | Despersions of delaminated particles in polymer foams |
| WO2000037242A1 (en) * | 1998-12-21 | 2000-06-29 | Magna International Of America, Inc. | Structural foam composite having nano-particle reinforcement and method of making the same |
| WO2000047657A2 (en) * | 1999-02-12 | 2000-08-17 | The Dow Chemical Company | Nanocomposite articles and process for making |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10184037B2 (en) | 2003-11-26 | 2019-01-22 | Owens Corning Intellectual Capital, Llc | Thermoplastic foams and method of forming them using nano-graphite |
| DE102004004237C5 (en) * | 2004-01-27 | 2009-11-12 | Woco Industrietechnik Gmbh | Process for the production of microporous plastic products and the moldings, profiles and granules obtainable by this process |
| US9187608B2 (en) | 2005-09-08 | 2015-11-17 | Owens Corning Intellectual Capital, Llc | Polystyrene foam containing a modifier-free nanoclay and having improved fire protection performance |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2003280166A8 (en) | 2004-01-19 |
| AU2003280166A1 (en) | 2004-01-19 |
| WO2004003063A8 (en) | 2004-07-22 |
| DE10229983A1 (en) | 2004-01-15 |
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