WO2011082747A2

WO2011082747A2 - Foamed body composed of thermoplastic polyesters and method for the production thereof

Info

Publication number: WO2011082747A2
Application number: PCT/EP2010/007316
Authority: WO
Inventors: Benedikt Moser; Richard John Artley; Dietmar Rakutt
Original assignee: 3A Technology & Management Ltd.
Priority date: 2009-12-14
Filing date: 2010-12-02
Publication date: 2011-07-14
Also published as: WO2011082747A3; CH702368A2

Abstract

The invention relates to a foamed body composed of thermoplastic polyesters with high homogeneity, low open-cell factor and high elongation at break under shear stress, wherein the polyester foam contains, based on the weight of the foamed body, from 0.1 to 20 wt% of nanoparticles selected from the series of carbon nanotubes and nanoclays, and at least one thermoplastic elastomer, such as a thermoplastic copolyester elastomer. The foamed bodies can be obtained by foaming a polyester of low intrinsic viscosity in a mixture with nanoparticles, thermoplastic copolyester elastomers and dianhydrides of tetracarboxylic acids. At least the thermoplastic copolyester elastomers and the dianhydrides of tetracarboxylic acids form a master batch which is admixed with the polyester. The nanoparticles can be added to the polyester, to the master batch or to both.

Description

Thermoplastic polyester foams and process for their preparation

The invention relates to polyester-containing foam body with high homogeneity, low off-set and high shear fracture elongation, containing functional thermoplastics and modifiers, means for producing the foam body and method for producing foam bodies by foaming of polyesters. For example, WO 93/12164 discloses foamed cellular polyesters and a process for their preparation. It is described that thermoplastic polyesters suitable for extrusion foaming have, for example, an intrinsic viscosity of more than 0.8 dl / g. In order to obtain the stated value of the intrinsic viscosity, a two-stage process is described, accordingly, a polyester having a

Intrinsic viscosity of higher than 0.52 dl / g with a dianhydride of an organic tetracarboxylic acid is added and reacted to obtain a polyester having an intrinsic viscosity of 0.85 to 1.95 dl / g. The foaming process can then be initiated by extrusion foaming with the thus prepared polyester. In some cases, further dianhydride can be added to an organic tetracarboxylic acid during extrusion foaming.

Disadvantage of said method is that two complex process steps are necessary to first mix the entire volume of polyester with the dianhydride of tetracarboxylic acid, and then bring it to a reaction temperature in a solid phase reactor and to keep for several hours at the end of the reaction to temperature , Only then does the actual foaming process follow.

According to US 5,288,764, foamed polyester can be obtained by forming a molten mixture and extruding this mixture. The

CONFIRMATION COPY Mixture is formed from a major proportion of polyester and a minor part of a mixture of polyester with a substance that has a chain extension, resp. Branch, causes. Particularly valuable foams of polyester have, for example, at low density, high homogeneity, low Offanzigkeit, high strength and in particular a high shear fracture strain. The foaming of polyesters into foam bodies is a process that is difficult to control. In particular, intrinsically viscous polyesters (IV) can either not be foamed at all or, if foaming is still possible, the foams have poor properties such as varying high density, high open-poredness, irregular pore distribution and low shear fracture elongation. However, it has been shown that further properties are desirable, such as a further improved mechanical strength, such as compressive strength and shear modulus, the foams, respectively. with the same mechanical strength of the foams, a reduced specific foam weight or conductivities for heat or electricity.

The invention has for its object to propose polyester-containing foam body as well as means and methods for their preparation to get to foam bodies with advantageous properties with respect to overall good mechanical properties and good conductivities, for example, for heat or electricity. The present invention describes foams which, for example, have improved compressive strength, an improved print modulus, a better shear strength and a better shear modulus over known foams at the same density. Or, conversely, foams which have the same compressive strength at low density, the same pressure modulus, the same shear strength and the same shear modulus According to the invention, this object is achieved in that the polyester-containing foam body contains nanoparticles selected from the series of carbon nanotubes and nanoclays.

According to the invention, the polyester-containing foam body may contain the nanoparticles, for example, in amounts of from 0.1 to 20.0% by weight, based on the weight of the foam body. Expediently, nanoparticles are present in amounts of 0.3% and more, advantageously of 0.5% and more, and in particular of 1.0% and more, in each case in% by weight, based on the weight of the foam body. Expediently, nanoparticles are present in amounts of 15.0% and less, advantageously 10.0% and less, and in particular 5.0% and smaller, in each case in% by weight, based on the weight of the foam body.

If nanoparticles contain carbon nanotubes, amounts of from 0.1 to 10.0% by weight, based on the weight of the foam body, are advantageous. Conveniently, carbon nanotubes in amounts of 0.3% and greater, and advantageously of 0.5% and greater, each in wt .-%, based on the weight of the foam body, included. Suitably carbon nanotubes are in amounts of 10.0% and smaller, advantageously of 5.0% and smaller and in particular of 3.0% and smaller, each in wt .-%, based on the weight of

Foam body, included.

If nanoclays are contained as nanoparticles, amounts of from 0.5 to 20.0% by weight, based on the weight of the foam body, are advantageous. Expediently, nanoclays are present in amounts of 0.5% and more, advantageously of 0.5% and more, and in particular of 2.0 and more, in each case in% by weight, based on the weight of the foam body. Expediently, nanoclays are present in amounts of 15.0% and less, advantageously 10.0% and less and in particular 5.0% and less, in each case in% by weight, based on the weight of the foam body. The nanoparticles can be contained in a mixture with any proportions of carbon nanotubes and nanoclays in amounts of from 0.1 to 20% by weight, based on the weight of the foam body.

Foamed bodies according to the present invention may have, for example, an open cell density of less than 8% and in particular of less than 4%.

Advantageously, foam bodies according to the invention have a shear fracture elongation of more than 12%, advantageously more than 16% and preferably more than 50%.

Known nanoparticles that are particularly applicable herein include the carbon nanotubes and nanoclays.

The Carbon Nano Tubes are also known as carbon nanotubes. Further equivalent terms for carbon nanotubes are nanoscale carbon tubes or the abbreviated designation "CNT" for carbon nanotubes and, in the following, the most commonly used form in the art, namely "CNT", will continue to be used. The CNTs are fullerenes and are carbon modifications with closed polyhedral structure. Known fields of application for CNT are found in the field of semiconductors or to improve the mechanical properties of conventional plastics

(www.de.wikipedia.org under "carbon nanotube").

As CNT, for example, catalytically, in an arc, by laser or by gas decomposition generated materials can be used. The CNTs can be single-walled or multi-walled, such as double-walled. The CNTs can be open or closed tubes. The CNTs may have, for example, from 0.4 nm (nanometers) to 50 nm in diameter and a length of 5 nm to 50Ό00 nm. The CNTs may also be sponge-like structures, ie 2- or 3-dimensional frameworks, of mutually cross-linked carbon nanotubes. The diameter of the individual tubes moves in the process The extent of the sponge structure, ie the side lengths of a framework body of CNT, can be given by way of example with 10 nm to 50Ό00 nm, advantageously with 1 Ό00 nm to 50Ό00 nm in each of the dimensions.

The material CNT is advantageously in granular form or in the form of particles, the particle size of 0.5 μιτι to 2000 μιτι, advantageously from 1 μ ^η ι to 1000 pm, is.

In the present case, the nanoclays are, for example, organically intercalated phyllosilicates. The Nanoclays are especially water-swellable natural or synthetic phyllosilicates. When swelling in the water, platelets in the nano-range dissolve, creating networks in the example, polymers or generally long-chain ions or other charged particles in the interlayers penetrate, intercalation, can. This results in intercalated nanoclays that can be extracted using other swelling agents. The original order in the phyllosilicates is lost through exfoliation. Fully exfoliated smectites, such as montmorillonite as an example of such a layered silicate, can form particle sizes with a very high aspect ratio of up to 1000, obtained by layers of about 1 nm in diameter, about 100 nm in width and 500-1000 nm in length.

In order for the inherently hydrophobic plastics to become processable with nanoclays, the natural or synthetic phyllosilicates generally have to be made orga- nophilic. As a method suitable for the organophilic modification of the sheet silicates, for example, a cation exchange can be used. The cation exchange can be carried out in the aqueous phase with cationic surfactants based on ammonium, phosphonium or sulfonium surfactants. Another method is acid activation, e.g. B. with hydrochloric acid, known. In order to be effective, it may be necessary for the nanoclay to be exfoliated in the polymer into which it is to be incorporated. In this way, the nanociays are uniformly distributed in the polymeric materials and there is a pre-exfoliation or the complete delamination / exfoliation after incorporation into the desired polymer.

With the nanociays, in particular from a swellable inorganic layer material, which can be surface-coated in a dry process with a pre-exfoliating additive or an additive mixture, a masterbatch can be prepared in order to be used in a production process or procedure.

Nanoparticles are advantageously functionalized to give, for example, a linkage, such as a covalent bond to a substance, such as a dianhydride of a tetracarboxylic acid, in particular a dianhydride of an organic tetracarboxylic acid, e.g. Pyromellitic dianhydride (PMDA), on polyolefins, such as polyethylene or polypropylene, on polycarbonates, on polyesters, on thermoplastic polyesters, such as thermoplastic polyester elastomers (TPEE), can take place. Possible functional groups on the nanoparticles are, for example, hydroxyl groups and epoxy groups.

The nanociays contained in the masterbatch have, for example, an average particle size of from 0.1 to 1000 μm, preferably from 0.1 to 100 μm, particularly preferably from 1 to 15 μm and very particularly preferably from 2 to 10 μm. In order to achieve the stated particle sizes, the nanociays may be partially or completely ground. Milling can be done for example by means of a jet mill, ball mill, vibrating mill, roller mill, impact mill, impact beater, attritor mill, pin mill, etc.

The foam bodies of polyesters according to the present invention contain functional thermoplastics. Suitable functional thermoplastics include, for example, polyolefins such as polyethylene or polypropylene, polycarbonates or thermoplastic elastomers such as TPEE (thermoplastic poly ester elastomers). The thermoplastic elastomers are preferred and are advantageously polymer blends or thermoplastic copolyester elastomers.

For example, foamed bodies according to the invention contain functional thermoplastics in amounts of from 0.5 to 15.0% by weight, and amounts of from 0.5 to 12% by weight, and preferably from 1.5 to 12% by weight, in each case are appropriate on the weight of the foam body.

The preferred thermoplastic elastomers consist of or contain polymers or a blend of polymers (blend) which exhibit properties similar to those of vulcanized rubber at service temperature but which can be processed and worked up at elevated temperatures, such as a thermoplastic. The polymer blends have a polymer matrix of hard thermoplastic with incorporated particles of soft crosslinked or uncrosslinked elastomers. The thermoplastic copolyester elastomers contain hard thermoplastic sequences and soft elastomeric sequences. The thermoplastic copolyester elastomers contain polyester blocks, expediently from a diol, preferably from 1,4-butanediol or 1,2-ethanediol, and a dicarboxylic acid, preferably terephthalic acid, which esterify with polyethers which carry hydroxyl end groups in a condensation reaction were.

Thermoplastic elastomers (for example according to prEN ISO 18064) are also known under the abbreviation TPE and the subgroups TPO (thermoplastic olefin elastomers), TPS (thermoplastic styrene elastomers), TPV (thermoplastic rubber vulcanizates), TPU (thermoplastic urethane elastomers), TPA

(thermoplastic polyamide elastomers), TPC (thermoplastic copolyester elastomers) and TPZ (other unclassified thermoplastic elastomers) known. The TPEs include block polymers or segment polymers, for example thermoplastic styrene block polymers, thermoplastic copolyesters, polyether esters, thermoplastic polyurethanes or polyether-polyamide Block copolymers. The TPEs obtain their elastomeric properties either by copolymerizing hard and soft blocks or blending a thermoplastic matrix. In the case of graft copolymerization, the hard segments form so-called domains, which function as physical crosslinks. TPE are repeatedly melted and processed. The TPE, described as thermoplastic copolyester elastomers, resp. also called TPC, are divided into the TPC-EE with soft segments with ether and ester linkages and the TPC-ES / -ET with soft polyester segments, respectively. Polyether. In the present case, the TPC-EE are of particular interest.

The thermoplastic copolyester elastomers, resp. thermoplastic copolyester or thermoplastic polyetherester, resp. elastomeric copolyethers are alternately constructed of hard polyester segments and soft polyether segments. Depending on the type and length of the hard and soft segments, a wide hardness range is adjustable. Thermoplastic copolyesters are block copolymers consisting on the one hand of amorphous soft segments of polyalkylene ether diols and / or long-chain aliphatic dicarboxylic acid esters and on the other hand of hard segments of crystalline polybutylene terephthalate. The preparation of the elastomeric copolyetheresters is carried out in the melt by transesterification reactions between a terephthalate ester, a polyalkylene ether glycol (for example polytetramethylene ether glycol, polyethylene oxide glycol or polypropylene oxide glycol) and a short-chain diol, for example 1,4-butanediol or 1,2-ethanediol.

For example, foam bodies according to the invention contain functional thermoplastics, such as thermoplastic elastomers, in amounts of from 0.5 to 15.0% by weight, based on the weight of the foam body. Suitably amounts of functional thermoplastics, such as thermoplastic elastomers, from 0.5 to 12 wt .-%, and preferably from 1, 5 to 12 wt .-%, each based on the weight of the foam body. In order to increase the molecular weight of polyesters, a modifier can be added to the polyester. The modifier is, for example, a dianhydride of an organic tetracarboxylic acid (tetracarboxylic acid dianhydride). Preferred dianhydrides are the dianhydrides of the following tetracarboxylic acids:

Benzene-1, 2,4,5-tetracarboxylic acid (pyromellitic acid),

3,3 ', 4,4'-biphenyltetracarboxylic acid,

3,3 ', 4,4'-benzophenonetetracarboxylic acid,

2,2-bis (3,4-dicarboxyphenyl) propane,

Bis (3,4-dicarboxyphenyl) ether,

Bis (3,4-dicarboxylphenyl) thioether,

Naphthalene-2,3,6,7-tetracarboxylic acid,

sulfone bis (3,4-dicarboxylphenyl)

Tetrahydrofuran-2, 3, 4, 5-tetraca rolysis,

2,2-bis (3,4-dicarboxlphenyl) hexafluoropropane,

1, 2,5,6 -naphthalenetetracarboxylic acid,

Bis (3,4-dicarboxyphenyl) sulfoxide

and mixtures thereof.

The preferred dianhydride is pyromellitic dianhydride (benzene-1, 2,4,5-tetracarboxylic acid 1, 2: 4,5-dianhydride).

Starting materials which can be used to produce foamed polyesters are polyesters, such as thermoplastic polyesters obtainable by polycondensation of aromatic dicarboxylic acids with diols. Examples of aromatic acids are terephthalic and isophthalic acids, naphthalene dicarboxylic acids and diphenyl ether dicarboxylic acids. Examples of diols are glycols such as ethylene glycol, tetraethylene glycol, cyclohexanedimethanol, 1,4-butanediol and 1,2-ethanediol.

Polyesters of or containing polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate copolymers containing up to 20% of isophthalic acid are preferred. A particularly important feature of the polyesters used as starting material, which are modified according to the invention and foamed to form the foam bodies according to the invention, is the intrinsic viscosity. It has not been possible to produce foams starting from polyesters having an intrinsic viscosity of about 0.4 dl / g. According to the present invention, starting materials, such as of polyesters having an intrinsic viscosity as low as about 0.4 dl / g and above, and especially of polyesters having an intrinsic viscosity of, for example, 0.6 to 0.7 dl / g and above, can reliably form foams be manufactured with the required properties. In order to increase low intrinsic viscosities, the proportion of modifier, in particular the tetracarboxylic dianhydride, based on the polyester used, must be increased accordingly. By choosing the concentration of modifier in the masterbatch and the amount of masterbatch used with respect to the amount of polyester, the intrinsic viscosity of the processed polyester, and hence its foamability, is easily controlled. For example, the intrinsic viscosity of 0.6 to 0.7 dl / g can be increased by the modification to above 1, 0 or even 1, 2 dl / g and above.

The present invention also relates to compositions for producing foam bodies from polyesters of high homogeneity, low open-cell content and high shear fracture elongation, containing nanoparticles, functional thermoplastics and as modifier dianhydrides of tetracarboxylic acids. The compositions are a masterbatch containing functional thermoplastics in amounts of from 12.5 to 87.5% by weight, based on the weight of the composition, and dianhydrides of tetracarboxylic acids in amounts of from 2.5 to 30% by weight on the weight of the agent as well as nanoparticles in amounts of 10 to 50 wt .-%, preferably 20 to 30%, based on the weight of the composition.

Preference is given to compositions for producing foam bodies from polyesters, where the agent is a premix comprising nanoparticles, functional thermoplastics, such as thermoplastic elastomers or thermoplastic copolymers. lyesterelastomere, in amounts of 10 to 87.5 wt .-% and dianhydrides of a tetracarboxylic acid in amounts of 2.5 to 30% by weight, nanoparticles in amounts of 10 to 50 wt .-%, based on the weight of the composition, and 0 to 70%, preferably 1 to 50 wt .-%, each based on the weight of the composition, stabilizers, nucleating agents, flame retardants and / or polyesters, suitably a polyester of the same quality, such as a starting polyester to be modified.

The means, i. the premix, can be prefabricated and temporarily stored. Thereafter, in the quantities provided, the premix and the polyesters to be foamed can be mixed together. This mixture of premix and polyesters can be further fed to the foaming process and processed into foam bodies.

The present invention also relates to a process for producing foam bodies from polyesters of high homogeneity and shear fracture elongation, containing functional thermoplastics and as modifying agent dianhydrides of a tetracarboxylic acid and nanoparticles.

The process for producing high homogeneity, low tack, and high rebound fracture strain polyester-containing foam bodies may be carried out to produce a blend containing polyester, nanoparticles from the carbon nanotube series or nanoclay in amounts of from 0.1 to 20.0 Wt .-%, based on the weight of the foam body, and at least one premix and the mixture to a foam body is foamed. The premixes containing in particular functional thermoplastics. A premix or at least one of the premixes contains a modifier of dianhydrides of tetracarboxylic acids,

Preference is given to a process for the production of polyester-containing foams of high homogeneity, low off-set and high shear fracture elongation, wherein the polyester nanoparticles, from the series of carbon nanotubes bes or Nanociays, in amounts of 0.1 to 20.0 wt .-%, based on the weight of the foam body, and a premix containing functional thermoplastics, mixed and foamed into a foam body.

According to another method for producing polyester-containing foam bodies, the polyester, the premix containing functional thermoplastics, nanoparticles, from the series of carbon nanotubes or Nanociays, in quantities in the foam body to 0.1 to 20 wt .-%, based on the Weight of the foam body lead, and a modifier of dianhydrides of tetracarboxylic acids are added.

According to another possible method for producing polyester-containing foams of high homogeneity, low open-cell content and high shear fracture elongation, the polyester nanoparticles, from the series of carbon nanotubes or Nanociays, in amounts in the foam body to 0.1 to 20 wt .-%, based on the weight of the foam body, mixed. The polyester blended with the nanoparticles may be mixed with a masterbatch containing functional thermoplastics and a modifier of dianhydrides of tetracarboxylic acids and then foamed to a foam body. The nanoparticles can be present in amounts of from 0.1 to 20% by weight, based on the weight of the foam body, in the foam body.

In yet another way, the process for the production of polyester-containing foam bodies can be carried out such that the polyester with two premixes containing functional thermoplastics, mixed and foamed into a foam body. A first premix is the nanoparticles, from the series of carbon nanotubes or Nanociays, in quantities in the foam body to 0.1 to 20 wt .-%, based on the weight of the

Lead foam body, mixed. The second premix is admixed with the modifier of dianhydrides of tetracarboxylic acids. In yet another way, the process for the production of polyester-containing foam bodies can be carried out by admixing nanoparticles from the series of carbon nanotubes or nanoclays with the polyester, and adding to the polyester a first premix containing functional thermoplastics and nanoparticles from the series the carbon nanotubes or Nanoclays, in amounts which in the foam body to 0.1 to 20 wt .-%, based on the weight of the foam body, contains. In addition, the polyester is additionally admixed with a second premix containing functional thermoplastics and a modifier of dianhydrides of tetracarboxylic acids.

In the aforementioned methods, the polyester, the nanoparticles as such and / or as part of at least one premix, and the masterbatch or masterbatches as components may be combined into a reactor or mixer, especially a single or twin screw extruder or a multi-screw extruder or a tandem machine of two

Single screw extruders or from a twin and a single screw extruder, fed and mixed therein

The abovementioned premixes may contain as further constituents, for example a total of 0 to 70%, preferably 0.1 to 70% by weight and in particular 1 to 50% by weight, for example polyesters, stabilizers, nucleating agents, fillers and flame retardants. The polyesters listed for the further ingredients may be of the same quality as the starting polyesters, e.g. with an intrinsic viscosity above about 0.4 dl / g and in particular polyester having an intrinsic viscosity of about 0.6 to 0.7 dl / g and above, be.

The preparation of the premix can be carried out by feeding the components into a mixer, for example a screw extruder, such as a single- or twin-screw extruder or a multi-screw extruder etc., and intimately mixing the components over a period of 0 to 120 seconds at temperatures of 200 to 260 ° C take place. The premix may be off applied to the mixer and in a further processable form, eg granulated, be.

To produce the foam body of polyesters is carried out by a mixing and foaming process. For this purpose, for example, a polyester having an intrinsic viscosity of at least 0.4 dl / g, and submitted a) mixed with the nanoparticles and the premix or b) mixed with nanoparticles premix or c) with the part of the nanoparticles and with the premix containing the other part of the nanoparticles, mixed and mixed. It may be used occasionally several premixes. For example, a masterbatch containing, in addition to the functional thermoplastic, the modifier of dianhydrides of tetracarboxylic acids and another masterbatch containing, in addition to the thermoplastic elastomer, the entire intended amount or at least a portion of the intended amount of nanoparticles can be used. The premix or premixes can be used in proportions of 1.0 to 20.0% by weight, based on the polyester. Shares of 2.0 to 4.0 wt .-%, based on the polyester are advantageous. In some cases, in addition to the polyester and the premix, resp. the premixes, other components of the mixing and foaming process, are supplied. These are the already mentioned stabilizers, fillers and flame retardants, which instead or not already contained in the premix, can be supplied. The amounts of further components are, for example, up to 15% by weight, advantageously from 0.1 to 15% by weight, based on the sum of polyester and premix. Other components, for example for controlling the cell size and the cell distribution in the foam, can also be added to the mixing and foaming process. These are for example up to 5 wt .-%, suitably 0.1 to 5 wt .-%, (based on the sum of polyester and premix) of metal compounds of I. to III. Group in the periodic system, such as sodium carbonate, calcium carbonate, aluminum or magnesium stearate, aluminum or Magnesium myrissate or sodium terephthalate and the other suitable

Compounds, such as e.g. Talc or titanium dioxide.

The components may be fed to and mixed in a reactor or mixer, for example a single or twin screw extruder or a multi-screw extruder or a tandem unit of two single-screw extruders combined or combined with one another, a twin-screw and a single-screw extruder. The residence time of the components in the reactor or mixer can be for example from 8 to 40 minutes. The temperature during the residence time can be from 240 to 320 ° C.

The reactor or mixer, for example, the said extruders, the blowing agent is also supplied to the foaming. Suitable propellants are, for example, easily vaporizable liquids, thermally decomposing substances which release gases or inert gases and mixtures or combinations of said agents. Easily vaporizable liquids include saturated aliphatic or cycloaliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons. Examples are butane, pentane, hexane, cyclohexane, ethanol, acetone and HFC 152a. C0 ₂ and nitrogen can be mentioned as inert gas. The blowing agent is usually fed into the extruder after the feed zone, the components.

At the shaping outlet opening of the extruder, the foam body of substantially substantially closed-cell form is formed continuously

Foam, which may for example have a round, rounded, rectangular or polygonal cross-section. The foam body can then be as far as required, according to the use, deformed, cut and / or joined. If foamed bodies are produced, then the foamed bodies can be stacked next to one another and / or one above the other and processed to form foam blocks, in particular homogeneous foam blocks, with mutual release-resistant connection, such as mutual bonding or, in particular, welding. The foam bodies may be plate-shaped and be stacked. The touching surfaces can be connected to each other over the entire surface, as if welded. This creates foam blocks with welds that run in the extrusion direction. It can, in particular transversely to the extrusion direction, resp. transverse to the welds, individual foam sheets are separated from the foam block.

The components can be fed to and mixed in a reactor or mixer, for example a single- or twin-screw extruder or a multi-screw extruder or a tandem unit consisting of two single-screw extruders combined together or combined with one another, a twin-screw extruder and a single-screw extruder. At the connection to the extruder, the mixed components can be introduced into the cavity of a one- or multi-part mold and foamed in the cavity. Alternatively, the mixed components in strands may contain the outlet port of the extruder, e.g. through a nozzle or nozzle plate with holes, leave, foam and the foam into granules, e.g. by underwater graining.

The foam body according to the invention has the advantageous features, such as extensive purity of variety with respect to the polymers and regular closed-cell pores.

The process according to the invention is also distinguished, for example, by the fact that no gel formation takes place during extrusion. The premix is fully miscible with the polyester and no second undesirable phase forms. The premix can be produced in devices known per se, the so-called compounding devices, the process being easy to control. The properties of the resulting foam body can also be controlled in a simple manner by the choice of the thermoplastic copolyester elastomer (TPC) and the soft elastomers and hard thermoplastic sequences contained therein.

Claims

claims

1. Foam body containing thermoplastic polyester, with high

Homogeneity and shear fracture elongation and low open-cell content, containing functional thermoplastics and as modifier dianhydrides of tetracarboxylic acids, characterized in that the foam body contains nanoparticles selected from the series of carbon nanotubes and Nanoclays.

2. Foamed body according to claim 1, characterized in that the nanoparticles in amounts of 0.1 to 20.0 wt .-%, based on the weight of the foam body, are included.

3. foam body according to at least one of claims 1 or 2, characterized in that as nanoparticles carbon nanotubes in amounts of 0.1 to 10.0 wt .-%, based on the weight of the foam body, are contained therein.

4. foam body according to at least one of claims 1 or 2, characterized in that as nanoparticles Nanoclays in amounts of 0.5 to 20 wt .-%, based on the weight of the foam body, are contained therein.

5. foam body according to at least one of claims 1 to 4, characterized in that the polyester foam has an open-cell content of less than 8% and in particular of less than 4%.

6. foam body according to at least one of claims 1 to 5, characterized in that the polyester foam has a shear fracture strain of more than 12%, suitably more than 16% and preferably more than 50%.

7. A process for the preparation of polyester-containing foam bodies of high homogeneity, low off-set and high shear fracture strain, wherein a polyester with at least one premix, one of which contains functional thermoplastics, mixed and foamed to form a foam body, characterized in that nanoparticles, from the series of Carbon nanotubes or Nanociays, in amounts of from 0.1 to 20.0 wt .-%, based on the weight of the foam body, mixed.

8. A process for the production of polyester-containing foam bodies according to claim 7, wherein a polyester is mixed with the premix containing functional thermoplastics and foamed into a foam body, characterized in that the premix comprises nanoparticles, from the series of carbon nanotubes or nanoclay, in amounts of 0.1 to 20.0 wt .-%, based on the weight of the foam body, and a modifier of dianhydrides of tetracarboxylic acids are added.

9. A process for the production of polyester-containing foams of high homogeneity, low off-set and high shear fracture strain according to claim 7, wherein a polyester with a premix containing functional thermoplastics, mixed and foamed to a foam body, characterized in that the polyester nanoparticles, from Row of carbon nanotubes or Nanociays, in amounts of 0, 1 to 20.0 wt .-%, based on the weight of the foam body, admixed and the premix contains a modifier of dianhydrides of tetracarboxylic acids.

10. A process for the production of polyester-containing foams of high homogeneity, low off-set and high shear fracture strain after Claim 7, wherein a polyester with two premixes containing functional thermoplastics is mixed and foamed to form a foam body, characterized in that the one premix comprises nanoparticles, from the series of carbon nanotubes or nanoclay, in amounts of in total 0, 1 to 20.0 wt .-% based on the weight of the foam body, admixed and the second premix of a modifier of dianhydrides of tetracarboxylic acids is added.

1 1. A process for the production of polyester-containing foam bodies according to claim 7, characterized in that the polyester nanoparticles from the series of carbon nanotubes or Nanociays, a first premix containing functional thermoplastics and nanoparticles from the series of carbon nanotubes or Nanociays, so the foam body contains nanoparticles in amounts of from 0.1 to 20.0% by weight, based on the weight of the foam body, and a second premix containing functional thermoplastics and a modifier of dianhydrides of tetracarboxylic acids.

12. A process for the preparation of foam bodies according to claim 7 to 1 1, characterized in that the polyester with the premix or premixes and the nanoparticles as components of a reactor or mixer, in particular a single- or twin-screw extruder or a multi-screw extruder or a tandem of two single-screw extruders combined or from a twin and a single-screw extruder, fed and mixed therein

13. A composition for producing foams containing polyester, with high homogeneity, low open-cell content and high shear fracture strain, containing as modifier dianhydrides of tetracarboxylic acids, characterized in that the composition comprises a premix containing functional thermoplastics, preferably thermoplastic copolyester elastomers, in amounts of from 10.0 to 87.5% by weight, based on the weight of the composition, of dianhydrides of tetracarboxylic acids in amounts of from 2.5 to 30% by weight, based on the weight of the composition, and of nanoparticles, in particular carbon nanotubes or nanoclays in amounts of from 10 to 50% by weight, based on the weight of the composition.

14. Foaming agent according to claim 13, characterized in that the agent is a premix containing thermoplastic copolyester elastomers in amounts of 12.5 to 87.5 wt .-%, suitably from 20 to 80 wt .-%, dianhydrides of tetracarboxylic acids in amounts of from 5 to 15% by weight, based on the weight of the composition, and of nanoparticles, in particular carbon nanotubes or nanoclays, in amounts of from 20 to 30%, based on the weight of the composition.

15. Foaming agent-producing agent according to claim 13, characterized in that the agent is a premix containing functional thermoplastics, preferably thermoplastic elastomers or thermoplastic copolyester elastomers, in amounts of from 10 to 87.5% by weight and dianhydrides of a tetracarboxylic acid in quantities from 2.5 to 30% by weight, nanoparticles in amounts of from 10 to 50% by weight, based on the weight of the composition, and from 0 to 70%, preferably from 1 to 50% by weight, in each case based on the weight of the composition at least one of the additives selected from stabilizers, nucleating agents, flame retardants and / or polyesters, suitably a polyester of the same quality as a starting polyester to be modified.