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  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
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  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
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  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
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  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
  • C08G18/3855—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/4236—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups
  • C08G18/4238—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6633—Compounds of group C08G18/42
  • C08G18/6637—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38
  • C08G18/664—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
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  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
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  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
  • C08G18/751—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring
  • C08G18/752—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group
  • C08G18/753—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group
  • C08G18/755—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing only one cycloaliphatic ring containing at least one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group containing one isocyanate or isothiocyanate group linked to the cycloaliphatic ring by means of an aliphatic group having a primary carbon atom next to the isocyanate or isothiocyanate group and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
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  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/20—Compounding polymers with additives, e.g. colouring
  • C08J3/205—Compounding polymers with additives, e.g. colouring in the presence of a continuous liquid phase
  • C08J3/21—Compounding polymers with additives, e.g. colouring in the presence of a continuous liquid phase the polymer being premixed with a liquid phase
  • C08J3/215—Compounding polymers with additives, e.g. colouring in the presence of a continuous liquid phase the polymer being premixed with a liquid phase at least one additive being also premixed with a liquid phase
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  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/06—Polyurethanes from polyesters
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  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
  • C08J2375/04—Polyurethanes
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  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
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  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/011—Nanostructured additives

Definitions

• the invention relates to carbon nanotube (CNT) filled, semi-crystalline polyurethane (PUR) compositions having improved electrical properties, which are obtainable based on water-based polyurethane-CNT mixtures.
• the invention further relates to a process for the preparation of the polyurethane compositions in which water-based polyurethane dispersions are mixed with carbon nanotubes which are dispersed in water.
• the invention further relates to films made by pressing or processing casting solutions.
• Semi-crystalline polyurethanes according to this invention are polyurethanes or mixtures of polyurethanes which, in the DSC measurement, have a melting or crystallization peak which corresponds to a melting enthalpy of at least 5 J / g, preferably 20 J / g and particularly preferably 40 J / g ,
• Carbon nanotubes are a high tensile, lightweight, electrically conductive material which has received much attention recently, particularly with respect to their use in polymer blends.
• Under carbon nanotubes are understood in the prior art mainly cylindrical carbon tubes with a diameter between 3 and 100 nm and a length which is a multiple of the diameter. These tubes consist of one or more layers of ordered carbon atoms and have a different nucleus in morphology. These carbon nanotubes are for example also referred to as "carbon fibrils” or “hollow carbon fibers”.
• Carbon nanotubes have long been known in the literature. Although Iijima (Publication: S. Iijima, Nature 354, 56-58, 1991) is generally referred to as the discoverer of nanotubes, these materials, particularly fibrous graphite materials having multiple layers of graphite, have been known since the 1970's and early 1980's, respectively. Tates and Baker (GB 1469930A1, 1977 and EP 56004 A2) described for the first time the deposition of very fine fibrous carbon from the catalytic decomposition of hydrocarbons. However, the carbon filaments made from short-chain hydrocarbons are no longer characterized in terms of their diameter.
• Typical structures of these carbon nanotubes are those of the cylinder type. In the case of the cylindrical structures, a distinction is made between the single-wall carbon nanotubes and the multi-walled monocarbon nanotubes cylindrical carbon nanotubes (Multi Wall Carbon Nano Tubes).
• Common processes for their production include arc discharge, laser ablation, chemical vapor deposition (CVD) and chemical vapor deposition (CCVD process).
• SWNTs single walled carbon nanotubes
• Latex systems appear to be the most promising, as the carbon nanotubes are more conserved than mechanical methods.
• the usage of Latex systems are environmentally friendly and avoid the difficulties of high-viscosity processing.
• thermoplastic polyurethanes which contain carbon nanotubes and are prepared by mixing thermoplastic polyurethanes and multi-walled carbon nanotubes in an extruder with subsequent processing by injection molding.
• a comparable method of producing polyurethane fibers containing functionalized MWNT is also described by Chen et al. (Composites Sci Tech 66, 3029-3034, 2006). Untreated and acid-treated MWNT were also incorporated into polymer composites using the latex method where the polyurethane was formed in situ and compared to a conventional blending method. Obviously, the functionalization of the nanotubes resulted in improved electrical and antistatic properties compared to untreated carbon nanotubes.
• thermoplastics with carbon nanotubes in which a comparatively small amount of CNT is necessary in order to achieve electrical percolation in thermoplastics.
• Single-walled carbon nanotubes were used.
• polymer blends which include both high molecular weight and low molecular weight of the same polymer, for the production of A-electrically conductive polymer composites using latex technology in the preparation of such blends.
• Nanocomposites are produced, which had improved thermal stability. This has been described by Xia et al. (Soft Matter 1, 386-394, 2005). The mechanical properties have been improved by the use of MWNTs. An agitation method for dispersing the carbon nanotubes proved to be much less effective.
• Kuan et al. (Composites Sci., Tech. 65, 1703-1710, 2005) use aminofunctionalized MWNTs and mix them with high shear prepolymers or use ultrasound to make composites.
• a comparable method by Jung et al. (Macromol Rapid Communication 27, 126-131, 2006) uses subsequent curing in a melt press for carboxylate functionalized MWNTs added to prepolymers with stirring. The carbon nanotubes acted as covalent crosslinkers.
• Xia et al. (Macromol Chem. Phys., 207, 1945-1952, 2006) used mixtures of polyurethanes and functionalized MWNTs, treated them several times with ultrasound and mixed them with a polyol in a ball mill, and then terminated the formation of the polyurethane. Although the stability of the intermediate MWNT polymer dispersion improves No major improvements in final properties were found compared to unfunctionalized MWNTs. Buffa et al. (Journal of Polymer Science, Polymer Physics 45, 490-501, 2007) showed that hydroxy-functionalized SWNTs drastically lost their conductivity but, on the other hand, gave composites with slightly increased modulus using a solution-based manufacturing method.
• the object of the present invention is to provide a method for producing electrically conductive polyurethane composites. It has been found that such PUR composites can be made by latex technology, as long as the polyurethane polymer is based on semicrystalline PUR.
• the present invention relates to carbon nanotube filled semi-crystalline polyurethane compositions having improved electrical properties based on water-based polyurethane CNT blends.
• water-based PU latexes are mixed with carbon nanotubes dispersed in water and then processed into, for example, films made by pressing or casting.
• the invention relates to an electrically conductive polyurethane composition
• an electrically conductive polyurethane composition comprising at least one polyurethane polymer and carbonaceous nanoparticles, characterized in that the polymer material has a substantial proportion of semi-crystalline polyurethane, preferably at least 10 wt .-% semi-crystalline polyurethane, and the carbon-like Nanoparticles at least 20%, preferably at least 50%, more preferably 100% carbon nanotubes.
• polyurethane composition in which the proportion of carbonaceous nanoparticles is at most 8% by weight, preferably at most 6% by weight, particularly preferably at most 5% by weight, particularly preferably at most 3% by weight.
• the conductivity of the particularly preferred embodiment, the polyurethane composition is at least 1 • 10 -5 S / cm, preferably at least 1 • 10 "4 S / cm, more preferably at least 1 ⁇ 10- 3 S / cm.
• composition which is characterized in that the composition as a carbonaceous nanoparticles to 100% Kohlenstoffhanorschreibchen and the proportion of carbon nanotubes in the composition is at most 5% by weight.
• a polyurethane composition is composed of
• the polymer is partially crystalline after drying and in the DSC measurement has a melting or crystallization peak corresponding to a melting enthalpy of at least 5 J / g, preferably 20 J / g and particularly preferably 40 J / g.
• polyurethane composition which is characterized in that the semi-crystalline polyurethanes are based on polyurethane latexes.
• the invention also provides a process for preparing electrically conductive polyurethane compositions, in particular the novel polyurethane compositions described above, from polyurethane polymers and carbonaceous nanoparticles, characterized in that
• Polyurethane dispersion is mixed,
• step d) the dried product from step c) is cured using heat
• polyurethane dispersion based on substantial amounts of semi-crystalline polyurethane, in particular a minimum proportion of 20 wt .-% semi-crystalline polyurethane.
• Preferred is a method which is characterized in that in the preparation of the aqueous dispersion of the carbonaceous nanoparticles a surface-active substance is added as a dispersing agent.
• the surfactant is especially selected from the series of hydrocarbon sulfates or sulfonates such as sodium dodecylsulfonate (SDS), the polyalkylene oxide based dispersants, the water dispersible pyrrolidones or block copolymer surfactants in the aqueous medium.
• the preparation of the aqueous dispersion according to step a) is carried out using ultrasound.
• the invention further relates to the use of the new polyurethane composition for the production of coatings in vehicle construction or for housing of electrical equipment.
• Carbon nanotubes according to the invention are all single-walled or multi-walled carbon nanotubes of the cylinder type, scroll type or onion-like structure. Preference is given to using multi-walled carbon nanotubes of the cylinder type, scroll type or mixtures thereof.
• Carbon nanotubes having a ratio of length to outer diameter of greater than 5, preferably greater than 100, are particularly preferably used.
• the carbon nanotubes are particularly preferably used in the form of agglomerates, the agglomerates in particular having an average diameter in the range of 0.05 to 5 mm, preferably 0.1 to 2 mm, particularly preferably 0.2 to 1 mm.
• the carbon nanotubes to be used have particularly preferably essentially an average diameter of 3 to 100 nm, preferably 5 to 80 nm, more preferably 6 to 60 nm.
• CNT structures In contrast to the initially mentioned known CNTs of the scroll type with only one continuous or interrupted graphene layer CNT structures have recently been found that consist of several graphene layers, which are combined into a stack and rolled up (multiscroll type).
• These carbon nanotubes and carbon nanotube agglomerates thereof are, for example, the subject of the still unpublished German patent application with the official file reference 102007044031.8. Their content is hereby incorporated with respect to the CNT and its preparation to the disclosure of this application.
• This CNT structure is similar to the simple scroll type carbon nanotubes as the structure of multi-walled cylindrical monotube carbon nanotubes (cylindrical MWNT) to the structure of single-walled cylindrical carbon nanotubes (cylindrical SWNT).
• the individual graphene or graphite layers in these carbon nanotubes seen in cross-section, evidently run continuously from the center of the CNT to the outer edge without interruption. This can be z.
• the methods known today for producing carbon nanotubes include arc, laser ablation and catalytic processes. In many of these processes, carbon black, amorphous carbon and high diameter fibers are by-produced. In the catalytic process, a distinction can be made between the deposition of supported catalyst particles and the deposition of in-situ formed metal centers with diameters in the nanometer range (so-called flow processes).
• CCVD Catalytic Carbon Vapor Deposition
• acetylene, methane, ethane, ethylene, butane, butene, butadiene, benzene and other carbon-containing reactants Preference is therefore given to using CNTs obtainable from catalytic processes.
• the catalysts usually include metals, metal oxides or decomposable or reducible metal components.
• metals for the catalyst Fe metals for the catalyst Fe
• Particularly advantageous catalyst systems for the production of CNTs are based on combinations of metals or metal compounds containing two or more elements from the series Fe, Co, Mn, Mo and Ni.
• a particularly preferred method for the production of carbon nanotubes is known from WO 2006/050903 A2.
• carbon nanotubes of various structures are produced, which can be removed from the process predominantly as carbon nanotube powder.
• Carbon nanotubes more suitable for the invention are obtained by methods basically described in the following references:
• WO86 / 03455A1 describes the production of carbon filaments having a cylindrical structure with a constant diameter of 3.5 to 70 nm, an aspect ratio (length to diameter ratio) greater than 100 and a core region. These fibrils consist of many continuous layers of ordered carbon atoms arranged concentrically around the cylindrical axis of the fibrils. These cylinder-like nanotubes were prepared by a CVD process from carbonaceous compounds by means of a metal-containing particle at a temperature between 85O 0 C and 1200 0 C.
• multi-walled carbon nanotubes in the form of nested seamless cylindrical nanotubes or also in the form of the described scroll or onion structures, today takes place commercially in large quantities, predominantly using catalytic processes. These processes usually show a higher yield than the above-mentioned arc and other processes and today are typically carried out on the kg scale (several hundred kilo / day worldwide).
• the multi-walled carbon nanotubes produced in this way are generally much cheaper than the single-walled nanotubes and are therefore used, for example. used as a performance-enhancing additive in other materials.
• nitric acid As the oxidizing agent for the functionalization of the carbon nanotubes, preference is given to using an oxidizing agent from the series: nitric acid, hydrogen peroxide, potassium permanganate and sulfuric acid or a possible mixture of these agents.
• Preferred is nitric acid or a mixture of nitric acid and sulfuric acid, more preferably nitric acid is used.
• the dispersion of carbon nanotubes in water can be achieved by means of ultrasonic methods, in the presence of surface-active substances.
• a widely used surface-active substance is sodium dodecyl sulfate, although other ionic or nonionic surface-active compounds or dispersing aids may also be used, and polymeric dispersants may also be used.
• polymeric dispersants may also be used.
• ultrasound method can optionally
• Other known processes for the preparation of dispersions are used, for. Using ball mills, high shear dispersion methods or using three-roll calendering methods.
• the conditions of the preferred ultrasonic treatment may be further optimized for each batch of carbon nanotubes, e.g. B. by applying an initially low
• Ultrasound treatment time can also be determined by the UV absorption of the
• Dispersion is tracked over time. It is also possible to determine the maximum weight fraction of carbon nanotubes and the minimum ratio of SCS to CNT by observing at which CNT content the dispersion continues to increase linearly, with full dispersion being determined by transmission electron microscopy (TEM).
• TEM transmission electron microscopy
• Particularly suitable semi-crystalline polyurethanes in the context of the invention are those composed of
• polyurethane latexes which are based on polyurethane latexes, characterized in that the polymer is partially crystalline after drying and in the DSC measurement has a melting or crystallization peak having a melting enthalpy of at least 5 J / g, preferably of 20 J / g and more preferably of 40 J / g corresponds.
• the aqueous dispersions according to the invention contain a mixture of 80 to 99.9% by weight, preferably 90 to 99.8% by weight, particularly preferably 95 to 99.5% by weight, very particularly preferably 96 to 99.0% by weight .-% wt .-% of the aqueous polyurethane or polyurethane-urea dispersion A) and 0.1 to 20 wt .-%, preferably 0.2 to 10 wt .-%, particularly preferably 0.5 to 5 wt .-%, most preferably 1 to 4 wt .-% carbon nanotubes.
• Suitable difunctional aliphatic polyester polyols A are, in particular, linear polyester diols, such as those known from aliphatic or cycloaliphatic
• Dicarboxylic acids such as succinic, methylsuccinic, glutaric, adi-pin, pimelines, cork, Azelaic, sebacic, nonandicarboxylic, decanedicarboxylic, tetrahydrophthalic, hexahydrophthalic, cyclohexanedicarboxylic, maleic, fumaric, malonic or mixtures thereof with polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, 1, 2-propanediol, di-, tri-, tetra-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2, 2-Dimethyl-1,3-propanediol, 1,4-d
• Dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol or mixtures thereof can be prepared.
• the free polycarboxylic acid it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesters.
• difunctional aliphatic polyester polyols A based on succinic acid, methylsuccinic acid, glutaric acid, adipic acid or maleic acid and 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol.
• difunctional aliphatic polyester polyols A based on adipic acid and 1,4-butanediol or 1,6-hexanediol.
• difunctional aliphatic polyester polyols A based on adipic acid and 1,4-butanediol.
• the molecular weight of the difunctional aliphatic polyester polyol A is between 400 and 5000 g / mol, preferably between 1500 and 3000 g / mol, more preferably between 1900 and 2500 g / mol.
• polystyrene resin preferably from 0 to 40%, particularly preferably from 0 to 30%.
• suitable structural components are polyethers, polyesters, polycarbonates, polylactones or polyamides.
• the polyols preferably have 2 to 4, particularly preferably 2 to 3, hydroxyl groups. Mixtures of such compounds are also possible.
• Suitable polyester polyols are, in particular, linear polyester diols or else weakly branched polyester polyols, such as those known from aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids, such as succinic, methylsuccinic, glutaric, adipic, pimelic, cork, Azelaic, sebacic, nonandicarboxylic, decanedicarboxylic, terephthalic, isophthalic, o-phthalic, tetrahydrophthalic, hexahydrophthalic, cyclohexanedicarboxylic, maleic, fumaric, malonic or trimellitic acids and acid anhydrides, such as o-phthalic , Trimellit or Succinic anhydride or mixtures thereof with polyhydric alcohols, for example ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-, tri-,
• cycloaliphatic and / or aromatic di- and polyhydroxyl compounds are also suitable as polyhydric alcohols for the preparation of the polyester polyols.
• the free polycarboxylic acid it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesters.
• the polyester polyols may also be homo- or copolymers of lactones, preferably by addition of lactones or lactone mixtures such as butyrolactone, e-caprolactone and / or methyl-e-caprolactone to the suitable di- and / or higher-functional starter molecules , such as the above-mentioned as structural components for polyester polyols, low molecular weight, polyhydric alcohols are obtained.
• lactones or lactone mixtures such as butyrolactone, e-caprolactone and / or methyl-e-caprolactone
• suitable di- and / or higher-functional starter molecules such as the above-mentioned as structural components for polyester polyols, low molecular weight, polyhydric alcohols are obtained.
• the corresponding polymers of e-caprolactone are preferred.
• substantially linear polyester polyols containing as structural components adipic acid and 1,4-butanediol and / or 1,6-hexanediol and / or 2,2-dimethyl-1,3-propanediol.
• hydroxyl-containing polycarbonates come into consideration as polyhydroxyl components, e.g. those obtained by reacting diols such as 1,4-butanediol and / or 1,6-hexanediol with diaryl carbonates, e.g. Diphenyl carbonate, dialkyl carbonates, such as. For example, dimethyl carbonate or phosgene can be prepared.
• diols such as 1,4-butanediol and / or 1,6-hexanediol
• diaryl carbonates e.g. Diphenyl carbonate, dialkyl carbonates, such as.
• dimethyl carbonate or phosgene can be prepared.
• Suitable polyether polyols are, for example, the polyaddition products of styrene oxides, ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin, and their Mischadditions- and graft products, as well as those obtained by condensation of polyhydric alcohols or mixtures thereof and by alkoxylation of polyhydric alcohols, amines and amino alcohols polyether polyols.
• a suitable Polyether polyols are the homo-, mixed and graft polymers of propylene oxide and ethylene oxide, which by addition of said epoxides to low molecular weight di- or triols, as mentioned above as synthesis components for polyester or higher polyfunctional low molecular weight polyols such as pentaerythritol or sugar or Water are accessible.
• di- or higher-functional polyols are polyester polyols, polylactones or polycarbonates, very particular preference is given to polyester polyols of the abovementioned type.
• Suitable as synthesis component B are di- or higher-functional polyol components having a molecular weight of from 62 to 399 daltons, for example polyethers, polyesters, polycarbonates, polylactones or polyamides, provided they have a molecular weight of from 62 to 399 daltons.
• polyhydric, in particular dihydric, alcohols mentioned under B for the preparation of the polyesterpolyols are the polyhydric, in particular dihydric, alcohols mentioned under B for the preparation of the polyesterpolyols.
• Preferred components B are ethanediol, diethylene glycol, 1,2-propanediol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol and 1,6- hexanediol.
• Particularly preferred components B are ethanediol, 1,4-butanediol and 1,6-hexanediol.
• Suitable structural components C are any organic compounds which have at least two free isocyanate groups per molecule. Preference is given to using diisocyanates Y (NCO) 2, where Y is a divalent aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a divalent cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, a divalent aromatic hydrocarbon radical having 6 to 15 carbon atoms or a divalent araliphatic hydrocarbon radical Hydrocarbon radical having 7 to 15 carbon atoms.
• NCO diisocyanates
• diisocyanates examples include tetramethylene diisocyanate, methylpentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1, 4-diisocyanato-cyclohexane, 1-isocyanato-3, 3, 5-trimethyl-5 - isocyanato-methyl-cyclohexane, 4,4'-diisocyanato -dicyclohexylmethane, 4,4'-diisocyanato-dicyclohexylpropane- (2,2), 1'-di-iso-cyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanato diphenylmethane, 2,2'- and 2,4'-diisocyanatodiphenylmethane,
• polyfunctional polyisocyanates known per se in polyurethane chemistry or else modified ones known per se, for example Carbodiimide groups, allophanate groups, isocyanurate groups, urethane groups and / or biuret polyisocyanates partially share.
• Preferred diisocyanates C are aliphatic and araliphatic diisocyanates such as hexamethylene diisocyanate, 1,4-diisocyanato-cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, 4,4'-diisocyanato-dicyclohexyl-methane or 4, 4'-diisocyanatodicyclohexylpropane (2,2) and mixtures consisting of these compounds.
• Particularly preferred structural components C are mixtures of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI).
• HDI hexamethylene diisocyanate
• IPDI 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane
• Suitable aminic chain extenders D are monoamino and / or diamino compounds, wherein chain extenders in the context of the invention also mean monoamines which lead to chain termination, and also mixtures thereof.
• Examples of monoamines are aliphatic and / or alicyclic primary and / or secondary monoamines such as ethylamine, diethylamine, the isomeric propyl and butylamines, higher linear aliphatic monoamines and cycloaliphatic monoamines such as cyclohexylamine.
• Further examples are amino alcohols, d. H. Compounds containing amino and hydroxyl groups in a molecule, such as. For example, ethanolamine, N-methylethanolamine, diethanolamine or 2-propanolamine.
• Further examples are monoamino compounds which additionally carry sulfonic acid and / or carboxyl groups, for example taurine, glycine or alanine.
• diamino compounds examples include 1, 2-ethanediamine, 1, 6-hexamethylenediamine, 1-amino-3,3,5-trimethyl-5-amino-methyl-cyclohexane (isophoronediamine), piperazine 1, 4-diaminocyclohexane or bis (4 -amino- i- cyclohexyl) -methane.
• piperazine 1, 4-diaminocyclohexane or bis (4 -amino- i- cyclohexyl) -methane.
• adipic dihydrazide hydrazine or hydrazine hydrate.
• Polyamines such as diethylenetriamine can be used instead of a diamino compound as a synthesis component.
• amino alcohols i. Compounds containing amino and hydroxyl groups in a molecule, such as. For example, l, 3-diamino-2-propanol, N- (2-hydroxyethyl) - ethylene 'di-' amine or N, N-bis (2-hydroxyethyl) ethylenediamine.
• diamino compounds having an ionic group which therefore additionally carry sulfonate and / or carboxylate groups are, for example, the sodium or potassium salts of N- (2-aminoethyl) -2-aminoethanesulfonic acid / carboxylic acid, N- (3-aminopropyl) 2-aminoethanesulfonic acid / carboxylic acid, N- (3-aminoproyl) -3-aminopropanesulfonic acid / carboxylic acid or N- (2-aminoethyl) -3-aminopropanesulfonic acid / carboxylic acid.
• amine chain extenders D are diethanolamine, 1,2-ethanediamine, 1-amino-3,3,5-trimethyl-5-amino-methylcyclohexane (isophoronediamine), piperazine, N- (2-hydroxyethyl) ethylenediamine and the sodium salts N- (2-aminoethyl) -2-aminoethanesulfonic acid / carboxylic acid.
• Diethanolamine, N- (2-hydroxyethyl) ethylenediamine and the sodium salt of N- (2-aminoethyl) -2-aminoethanesulfonic acid are particularly preferred.
• the polymer on which the dispersions of the invention are based contains ionic or potentially ionic groups for hydrophilization, which may be either cationic or anionic in nature. Preferred are sulfonate and carboxylate groups. Alternatively, it is also possible to use those groups which can be converted into the abovementioned ionic groups by salt formation (potentially ionic groups).
• the hydrophilic groups can be introduced into the polymer via components A, B and / or D. They are preferably introduced via the components B) or D, more preferably via the component D, very particularly preferably via the sodium salt of N- (2-aminoethyl) -2-aminoethanesulfonic acid as the amino acid chain extender D.
• the polymer is semi-crystalline after drying.
• Partly crystalline means that the polymer or polymers have a degree of crystallinity of 5 to 100%, preferably 20 to 100%. Crystallinity in this context means that in the DSC of the polymers with increasing temperature a maximum is run through, which is caused by the melting of regular partial structures in the polymer.
• the melting peak represents a kind of fingerprint of the crystalline structure of the polymer. When passing through a melt crystallization cycle, the melting enthalpy can be determined from the area of the melting or crystallization peak.
• it is at least 5 J / g, preferably at least 20 J / g and particularly preferably at least 40 J / g.
• the aqueous polyurethane or polyurethane-urea dispersion is preferably prepared by the acetone process.
• prepolymers of components A, optionally B and C are prepared, dissolved in acetone and chain-extended with the components D. After dispersion with water, the acetone is distilled off.
• the application and performance of the acetone process is known in the art and to those skilled in the art.
• Fig. 1 DSC curve of partially crystalline Dispercoll U56
• FIG. 2 DSC curve of amorphous Dispercoll U42
• FIG. 3 DSC curve of partially crystalline Dispercoll U54.
• the mixture was centrifuged at 3500 rpm for half an hour (Vanuge RF, Heraeus sepatech) and then decanted to remove residual solids.
• the dispersion that was obtained contained more than 95% of the carbon nanotubes (determined gravimet ⁇ sch).
• Dispercoll U56 type polyurethane latex (semi-ki-stable, low molecular weight polyurethane dispersion based on adipic acid / butanediol polyester, manufacturer Bayer Mate ⁇ alScience AG).
• the DSC curve (Perkm Elmer DSC 7) on a dried film Dispercoll U56 at a heating rate of 20 K / min is given in Fig. 1 and shows a melting or crystal peak of 58.5 J / g.
• the amount of latex and CNT dispersion necessary for the final composite was mixed with intensive stirring for one hour. Then a Petn cup was placed on a sand bath (on Barnstead / Thermolyne Cimarec 3 Hotplate heater) and adjusted horizontally. Subsequently, the CNT latex mixture was filled. The temperature of the hot plate was set at 60 0 C and the film dried overnight.
• the sample was further dried under vacuum for one day.
• the resulting films often peeled off easily, but occasionally with severe deformations due to the film's strong adhesion to the glass.
• the use of small amounts of water facilitated the detachment of the films from the dishes without change in shape.
• After detachment of the films they were again dried under reduced pressure.
• the film thickness was measured in each case with a mechanical measuring device.
• the conductivity of the films was determined by a two-point measuring method using a Keithley 6512 electrometer, optionally with increased accuracy by a four-point measurement using an additional Keithley 220 power source. For this, four parallel lines of colloidal graphite (1 cm long and 1 cm line spacing) were applied as an electrode to the surface of the films.
• the conductivity was determined on a 1 cm 2 surface and can be described as follows:
• R was derived by plotting the measured voltage against the preselected current.
• the film thickness d was determined separately.
• the results of the study are shown in Table 1. They show good electrical conductivity in the CNT-polyurethane blends, especially at CNT concentrations exceeding 2% by weight.
• Example 2 The same procedure as in Example 1 was used, but instead of the semicrystalline Dispercoll U 56, the amorphous Dispercoll U42 (amorphous, high molecular weight polyurethane dispersion based on phthalic anhydride / hexanediol polyester, manufacturer Bayer MaterialScience AG) was used as a polyurethane dispersion.
• the DSC curve Perkin Elmer DSC 7) on a dried film Dispercoll U42 at a heating rate of 20 K / min is shown in FIG. 2 given and shows no apparent melting or crystallization peak.
• the results of the conductivity measurements on the dried films - see Table 2 - show a comparatively low electrical conductivity of the resulting composite, even at a CNT content of 8 wt .-%.
• Dispercoll U54 semi-crystalline Dispercoll U54 (semi-crystalline, high molecular weight polyurethane dispersion based on adipic acid / butanediol polyester, produced by Bayer MaterialScience AG), which has a higher molecular weight than Dispercoll U56, has now been used and compared with Dispercoll U56 and Dispercoll U42.
• the DSC curve Perkin Elmer DSC 7) on a dried Dispercoll U54 film at a heating rate of 20 K / min is given in Fig. 3 and shows a melting or crystallization peak of 52.1 J / g.
• the surface electrical resistance of the films obtained was measured by two-point measurement at an electrode distance of 2 mm (Multimeter: Metra Hit One Plus, Gossen Metrawatt GmbH).
• the results, shown in Figure 4 show good electrical conductivity of the semi-crystalline polyurethane-CNT blends with a percolation threshold at about 2.5 wt% CNT and a comparatively low conductivity of the corresponding Dispercoll U42 composites.

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