EP2268738A1

EP2268738A1 - Reaction resin based on an unsaturated polyester, vinyl compounds and hydrocarbon nanotubes that can be cured radically

Info

Publication number: EP2268738A1
Application number: EP09733824A
Authority: EP
Inventors: Stefan BAHNMÜLLER; Helmut Meyer; Helmut Ritter; Michael Klink; Serguei Kostromine
Original assignee: Bayer MaterialScience AG
Current assignee: Bayer Intellectual Property GmbH
Priority date: 2008-04-22
Filing date: 2009-04-09
Publication date: 2011-01-05
Also published as: US20110046252A1; DE102008020135A1; JP2011519986A; WO2009129936A1

Abstract

A reaction resin based on an unsaturated polyester, one or more vinyl compounds and hydrocarbon nanotubes that can be cured radically is described, wherein hydrocarbon nanotubes are covalently bound to the unsaturated polyester.

Description

Reaction resin based on an unsaturated polyester, free-radically curable vinyl compounds and carbon nanotubes

The invention relates to a curable molding compound reinforced with carbon nanotubes (hereinafter also referred to as carbon nanotubes or CNTs for short) comprising at least one unsaturated polyester resin (abbreviated to UP resin) and at least one free-radically polymerizable vinyl monomer, the carbon nanotubes containing the unsaturated polyester resin covalently linked.

UP resins are known per se. They have a large number of polymerizable double bonds, which serve mainly as a crosslinking component in the polymerization of the miscible with them vinyl monomer and thus cause the curing of the resin (Ullmann's Encyclopedia of Industrial Chemistry, 1992 V.A21).

The UP resins are widely used as a molding compound, especially for various applications in the construction, construction and electrical industries. As processing methods, for example, pressing and injection molding methods are used. The subsequent curing takes place thermally usually under the action of organic peroxides as initiators which are added to the UP molding compositions already during production.

In order to keep up with the ever-increasing demands with regard to the mechanical strength of the polymer parts, the molding compositions are usually provided with reinforcing agents (glass fibers, mineral fillers such as talc and calcium carbonate, carbon fibers and various carbon blacks). It is frequently noted that the improvement of a material property (e.g., strength) is associated with a significant deterioration of one or more other properties (e.g., fracture toughness).

In recent years, more and more nanoparticulate fillers are known in which this counteracting effect on strength and fracture toughness is not so pronounced. Carbon nanotubes (CNTs), which have an outstanding combination of mechanical and physical properties, occupy a special position in this group. Known carbon nanotubes with the perfect crystalline structure have a diameter in the nanometer range and reach a length of up to 1 mm and more. They have a very high modulus of elasticity up to about 1 TPa and a strength of 50-100 GPa. In addition, they are excellent electrical and thermal conductors. It is to be expected in principle that such nanotubes, when incorporated into thermoplastic and in thermoreactive polymeric compositions, can not only positively influence their mechanical profile, but also make the material electrically conductive. In the case of UP resins this has additional This option is of particular importance because these composites based on UP resins are often used in the electrical and electronics industry.

Recently, work has been reported using both single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) as additives in UP resins.

The published patent application WO 2005 / 108485A2 describes the possible preparation of stable dispersions from unmodified CNTs in various polymer matrices (PVC, PVCC, PVDF, PMMA, PC, PA, PE, PS, PVA, PVAc, etc.). The CNTs are stabilized in the polymer matrices by addition of a copolymer containing acid, amino and anhydride groups and soluble in the above polymers. The ratio of CNTs to polymer [m (CNT) / m (copolymer)] is between 0.001% by weight and 1.0% by weight.

In the patent EP 1 580219 Bl a process for the production of CNTs reinforced composite materials is described. The method also includes hydrophilic CNTs, i. those which carry hydrophilic groups. In order to obtain a CNT-reinforced resin raw material, the CNTs and the finished polymer are dispersed in various solvents, both solutions are mixed together, and the solvents are removed. The hydrophilic groups are introduced by irradiation with UV light, by plasma treatment and / or by Naßbehariuluπg with a strong oxidizing agent in CNTs. The resin material includes epoxy resins, phenolic resins, melamine resins, furan resins and unsaturated polyester resins. The CNT-reinforced raw material is further processed by injection molding and compression molding.

Ago et. al. (Adv. Mater. 2002, 14, 19, 1380-1383) investigated the preparation of composites based on CNTs and unsaturated polyesters in the magnetic field.

Studies by Tanoglu and Schubert, (European Polymer Journal, 2007, 43, 2, 374-379) show that unsaturated polyesters reinforced with unfunctionalized CNTs and with CNTs bearing amino groups exhibit higher tensile elongation than the pure polymer , They found that as the amount of CNTs in the composite increased, the tensile strain of the resulting materials increased.

The object of the present invention was to find ways of using CNTs in resins of unsaturated polyesters, which bring about a further significant improvement in the mechanical properties of the resulting molded articles with the lowest possible total concentration of the CNTs used. All previous studies have one thing in common: The SWCNTs or MWSNTs used as additives are present as a physical mixture in addition to the polymer matrix.

Surprisingly, it has been found that when CNTs, particularly in an amount of 0.001 to 1.0 wt.%, Are incorporated into an UP resin molding compound so as to be covalently bonded to the unsaturated polyester resin, a substantial increase in the tensile yield strength of the composite up to a level of at least 15 N / mm2, in some cases even reaching a level of at least 25 N / mm2.

Comparative tests have shown that these values exceed the tensile strength of the sample without CNTs by at least 300%. The gain gained is significantly greater than when using the non-covalently bound CNTs.

The invention relates to a reaction resin based on an unsaturated polyester, one or more free-radically curable vinyl compounds and carbon nanotubes, characterized in that carbon nanotubes are covalently bonded to the unsaturated polyester.

The invention likewise relates to the unsaturated polyester which has undergone at least one covalent bond with at least one CNT particle and in this form can be used as an essential component for the preparation of the polyester resin.

Preference is given to a reaction resin which is characterized in that the unsaturated polyester is selected from units of

a) α, ß-unsaturated acid components

b) one or more polyhydric alcohols and

c) modified carbon nanotubes carrying one or more carboxylic acid or alcohol groups, is constructed.

Unsaturated polyester in the context of the invention is understood to mean condensation products which have in their polymeric backbone the ester group (-COO-) and carbon-carbon double bonds (-CH = CH-). Such products are generally prepared by melt or azeotropic condensation of polybasic, especially dibasic carboxylic acids and their esterifiable derivatives, in particular their anhydrides or alkyl esters, which are ester-linked with polyhydric, especially dihydric alcohols, and optionally contain additional radicals of monohydric carboxylic acids or monohydric alcohols, at least some of the starting materials have ethylenically unsaturated copolymerizable groups. Another part of the feedstocks are carbon nanotubes which are modified so that they carry at least one chemical moiety, which can enter into at least one ester bond with the other starting materials of the condensation, which connects the carbon nanotubes with the polyester backbone.

Preference is given to a reaction resin which is characterized in that the resin contains from 20 to 90% by weight, preferably from 30 to 80% by weight, particularly preferably from 50 to 75% by weight, of unsaturated polyester with covalently bound carbon nanotubes.

In particular, α, β-unsaturated dicarboxylic acids or unsaturated diols are considered as carriers of the carbon-carbon double bonds, preference being given to α, β-unsaturated dicarboxylic acids.

Citracon, fumaric, itaconic, mesaconic and maleic acid or their anhydrides or alkyl esters, preferably methyl esters, are particularly preferred as α, β-unsaturated acid components, with fumaric acid, maleic acid and their anhydride being very particularly preferred.

As further acid components, it is additionally possible to use aliphatic, cycloaliphatic and / or aromatic mono-, di- and / or polycarboxylic acids, such as sebacic acid, dodecanedioic acid,

Adipic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic acid,

Methylhexahydrophtalsäure, tetrahydrophthalic acid, phthalic, isophthalic, terphthalic, trimellitic and Promellitsäuren be used for the invention relevant condensation reaction. Such

Acid components can be wholly or partly in the form of anhydrides or alkyl, preferably methyl esters.

As a further component, the modified carbon nanotubes are used, which carry at least one carboxyl group per carbon nanotube. In particular, such carbon nanotubes are understood to be single wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs), preferably multiwall carbon nanotubes (MWCNTs), which are filled with a strong oxidizing agent, e.g. fuming nitric acid, are treated so that they can form carboxylic acid groups at the ends of the particles and at defect sites on the surface of the nanotubes. Such modified carbon nanotubes per se which carry carboxylic acid groups and their production processes are basically known (H.Hu, R.C. Haddon, Chem. Phys Let., 2001, 304, 25).

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, ozone, potassium permanganate and sulfuric acid or a possible mixture of these agents. It is preferred Nitric acid or a mixture of nitric acid and sulfuric acid, more preferably nitric acid is used.

Also preferred is a reaction resin characterized in that the carbon nanotubes are functionalized with oxygen-containing groups of the series -OH and -COOH which at least partially form in the covalent bond to the polyester.

Particularly preferred is a reaction resin in which the proportion of functional groups -OH and / or -COOH of the carbon nanotubes is at least 5 mol%, preferably at least 10 mol%.

Carbon nanotubes in the context of 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.

The carbon nanotubes are used in particular in an amount of 0.01 to 10 wt .-%, preferably 0.1 to 5 wt .-% based on the mixture of polymer and carbon nanotubes in the finished compound. In masterbatches, the concentration of carbon nanotubes may be greater.

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, particularly preferably 6 to 60 nm.

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 which consist of several graphene layers which are combined into a stack and rolled up (multiscroll type). These carbon nanotubes and carbon nanotube agglomerates thereof, for example, are 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 related to the carbon nanotubes of the simple scroll type comparatively like the structure of multi-walled cylindrical monocarbon nanotubes (cylindrical MWNT) to the structure of single-walled cylindrical carbon nanotubes (cylindrical SWNT).

Unlike the onion-type structures, 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. B. allow an improved and faster intercalation of other materials in the tube framework, as more open edges than entry zone of the intercalates are available in the

Comparison to single-scroll CNTs (Carbon 34, 1996, 1301-3) or onion-type CNTs (Science 263, 1994, 1744-7).

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). In the production via the catalytic deposition of carbon at reaction conditions gaseous hydrocarbons (hereinafter CCVD, Catalytic Carbon Vapor Deposition) are given as possible carbon donors 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. For example, in the prior art, the metals mentioned for the catalyst are Fe, Mo, Ni, V, Mn, Sn, Co, Cu and other subgroup elements. Although the individual metals usually have a tendency to promote the formation of carbon nanotubes, according to the prior art, high yields and low levels of amorphous carbons are advantageously achieved with those metal catalysts based on a combination of the above-mentioned metals. CNTs obtainable using mixed catalysts are therefore preferred to use.

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. The formation of carbon nanotubes and the properties of the tubes formed are known to depend in complex manner on the metal component used as a catalyst or a combination of several metal components, the catalyst support material optionally used and the interaction between catalyst and support, the reactant gas and partial pressure, an admixture of hydrogen or other gases, the reaction temperature and the residence time or the reactor used.

A particularly preferred method for the production of carbon nanotubes is known from WO 2006/050903 A2.

In the various methods mentioned so far using various catalyst systems, 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:

The production of carbon nanotubes with diameters smaller than 100 nm is described for the first time in EP 205 556 Bl. For the preparation here light (ie, short- and medium-chain aliphatic or mononuclear or dinuclear aromatic) hydrocarbons and an iron-based catalyst are used, are decomposed at the carbon carrier compounds at a temperature above 800-900 ⁰ C.

WO86 / 03455A1 describes the preparation of carbon filaments having a cylindrical structure with a constant diameter of 3.5 to 70 nm, an aspect ratio

(Ratio of length to diameter) of 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 cylindrical nanotubes were prepared by a CVD process from carbonaceous compounds by means of a metal-containing particle at a temperature between 850 ⁰ C and 1200 ⁰ C.

From WO2007 / 093337A2, a method for the preparation of a catalyst is known, which is suitable for the production of conventional carbon nanotubes with a cylindrical structure. When using this catalyst in a fixed bed, higher yields of cylindrical carbon nanotubes with a diameter in the range of 5 to 30 nm are obtained.

An entirely different way of producing cylindrical carbon nanotubes has been described by Oberlin, Endo and Koyam (Carbon 14, 1976, 133). This will be aromatic Hydrocarbons, such as benzene, reacted on a metal catalyst. The resulting carbon nanotubes show a well-defined, graphitic, hollow core that is about the diameter of the catalyst particle, on which there is another less graphitic ordered carbon. The entire carbon nanotube can be graphitized by treatment at high temperature (2500 ^° C - 3000 ^° C).

Most of the above methods (with arc, spray pyrolysis or CVD) are used today for the production of carbon nanotubes. However, the preparation of single-walled cylindrical carbon nanotubes is very complex in terms of apparatus and proceeds according to the known processes with very low formation rate and often also with many side reactions which lead to a high proportion of undesired impurities, i. the yield of such processes is comparatively low. Therefore, the production of such carbon nanotubes is still extremely technically complex today and they are therefore used mainly for highly specialized applications in small quantities. Their application, however, is conceivable for the invention, but less preferred than the use of multi-wall CNTs of the cylinder or scroll type.

The production of 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.

Preferred alcohol components are polyhydric alcohols from the series: linear and / or branched aliphatic and / or cycloaliphatic and / or aromatic diols and / or polyols, such as ethylene glycol, 1,2- and / or 1,3-propanediol, 1,2- and / or 1,4-butanediol, 1,3-butylethylpropanediol, 1,3-methylpropanediol, 1,5-pentanediol, 1,6-hydroxyanediol, diethylene, triethylene, tetraethylene glycol, cyclohexanedimethanol, glycerol, neopentyl glycol, trimethylolethane, trimethylolpropane, Pentaerythritol, bisphenol A, B, C, F, neobornylene glycol, 1,4-benzyldimethanol and 1,4-benzyldiethanol, most preferably butanediol.

The alcohol component is used in particular in a molar ratio of 0.8 to 1.5 to 1 to the sum of the acid components including the carbon nanotubes. Prefers the ratio of the alcohol component to the sum of the acid components is from 0.9 to 1.1 to 1.

The unsaturated polyesters are prepared by melt condensation or condensation under azeotropic conditions at a temperature of 80 to 220 ⁰ C from their above-mentioned starting components by continuous or batch processes by processes known in the art.

To prepare the curable molding composition, at least one polymerizable vinyl monomer is usually added to the unsaturated polyester. For example, styrene, D-methylstyrene, vinyltoluene, methyl methacrylate, vinyl acetate, diallyl phthalate and diallyl isophthalate are added. Particularly preferred is styrene.

The proportion by weight of the vinyl monomer added is preferably from 5 to 70% of the total molding composition. Particularly preferred is a weight proportion of the added vinyl monomer of 30 to 60 wt.%.

A further constituent of the curable molding composition (reaction resin), which is in particular from 0.1 to 4% by weight and preferably from 0.2 to 2% by weight, is a polymerization initiator. Conventional above 50 ⁰ C decomposing into peroxide peroxides such as diacyl peroxides, peroxydicarbonates, peroxyesters, perketals, hydroxyperoxides, ketoperoxides and dialkyl peroxides can be used as initiators. Also suitable are typical azo initiators.

The new reaction resin can further components from the group: fillers, pigments, dispersants, stabilizers, lubricants and flame retardants; Liquid additives, in particular water or oils and / or gaseous fillers, in particular air, nitrogen or carbon dioxide are admixed.

As further fillers, dyes and pigments, chalk, quartz powder, talc, kaolin can be added in amounts of from 0 to 300% by weight. Liquid additives such as water or oils, and / or gaseous fillers, such as air, nitrogen, carbon dioxide, are optionally also used.

As a shrinkage-reducing or elasticizing agent, thermoplastic polymers such as polystyrene, polymethyl methacrylate, polyvinyl acetate, saturated polyesters and thermoplastic polyurethanes are preferably added in amounts of from 5 to 50% by weight (based on the total UP resin). Oxides and hydroxides of magnesium, zinc or calcium may optionally be added as thickening agents of the molding composition. Also suitable as thickening agents are isocyanates, optionally in combination with amine.

Other substances that can be added to the molding composition are inhibitors, lubricants, accelerators, mold release agents and flame retardants.

To further reinforce the moldings, inorganic and / or organic fibers of glass, cellulose, polyethylene, polyamide or also carbon fibers in the form of short fibers or long fibers, webs, fabrics or mats can be presented to the molding composition (reaction resin) or incorporated during processing.

The prefabricated molding compound (reaction resin) is brought into a mold by filling, pressing or injection molding and cured at temperatures between 60 and 200 ⁰ C.

Likewise, the preformed molding compounds can be applied and cured from reactive resin as coatings, fillers, adhesives or as foams.

Another object of the invention is a process for preparing the inventive curable molding compositions of unsaturated polyester resin (UP resin), which includes the covalently bonded modified carbon nanotubes.

The novel process for preparing the novel reaction resin is characterized in that carbon nanotubes are functionalized by one or more carboxylic acid or alcohol groups by oxidation, the functionalized carbon nanotubes being dispersed in one or more polyhydric alcohols, especially in a diol, with an unsaturated acid component in particular Maleic acid, fumaric acid or maleic anhydride, mixed and condensed to form an unsaturated polyester, wherein the functionalized carbon nanotubes are covalently bonded and this polyester one or more vinyl monomers selected from the series: styrene, D-methyl styrene, methyl methacrylate, vinyl toluene, vinyl acetate, diallyl phthalate and diallyl isophthalate and a radical initiator added.

Specifically, the new method consists in particular of the following steps described below:

chemical modification of the carbon nanotubes (step 1), which serves to bring to the surface of the particles the carboxylic acid groups. The modification of

Carbon nanotubes are carried out at elevated temperature in an oxidizing acid, e.g.

Sulfuric acid or fuming nitric acid. Successful implementation can be achieved with FT-IR Spectroscopy can be detected. At a wavelength of 1684 cm-1, a broad band appears, attributable to the carbonyl valence vibration of aromatic carboxylic acids. This chemical modification improves the dispersion behavior of the CNTs and leads to significant stabilization of the dispersions.

Preparation of the unsaturated polyester by the condensation reaction of a reaction mixture (step 2) consisting of the modified in step 1 CNTs dispersed in a diol, and an unsaturated dicarboxylic acid or its anhydride, which serves to covalently connect the carbon nanotubes with the unsaturated polyester , Such bonding leads to a better distribution of the CNTs in the molding composition and to the secure incorporation of the CNTs into the polymeric network of the cured molding. These are the best conditions to achieve a significant improvement in the mechanical properties of the molding.

The CNTs modified in step 1 in an amount of in particular from 0.001 to 1% by weight, based on the total weight of the reaction mixture, are e.g. with an ultrasonic disintegrator (e.g., Branson) very finely suspended in a diol. The sonication proceeds in particular in several steps, the breaks serving for the cooling of the dispersion.

During sonication, it is also necessary to ensure constant cooling of the dispersion.

The resulting stable suspension is at a deficit, in particular a 5%

Subcutaneous anhydride of an unsaturated dibasic carboxylic acid added and rinsed in particular at 80 ⁰ C with nitrogen. After up to 16h precondensation eg at 100 ⁰ C is the

Suspension then with a water, especially for several hours at elevated temperature, for example, stirred at 190 ⁰ C for 5 h.

The so-formed nanotube polyester reaction product is in particular cooled down to 140 ⁰ C and in a weight ratio of preferably 1: 2 to 2: 1 with a vinyl monomer added (Step 3). To ensure complete mixing of the components, the reaction mixture is stirred, in particular for 1 min at 14O ⁰ C and then cooled to room temperature.

The molding material is then added to form the reaction resin with a peroxide initiator and optionally poured into molds. The crosslinking of the resin may be carried out at elevated temperature, e.g. at 80 ° C follow.

In the following examples, comparative samples were prepared after basically the same measures, which contain unmodified CNTs or no CNTs. A particularly preferred embodiment of the invention are unsaturated polyesters with covalently bound carbon nanotubes and the resulting curable molding compositions which are prepared from the following components by the method described above, wherein

- Baytubes C150P from MaterialScience AG as a carbon nanotube,

Maleic anhydride as the acid component,

1, 4-butanediol as a polyhydric alcohol,

Styrene as vinyl monomer and

Dibenzoyl peroxide (DBPO) can be used as an initiator.

The resulting cured moldings and films were investigated as follows in the examples:

The invention is explained in more detail below by the examples, which, however, do not represent a limitation of the invention.

Examples

example 1

Standard manufacturing procedure

The standard procedure for the preparation of covalently bonded modified MWCNTs-reinforced unsaturated polyester resins crosslinked with styrene is as follows: Carbon nanotubes (Baytubes C 150 P, manufactured by Bayer MaterialScience AG) were oxidized by boiling in fuming nitric acid for 18 hours. The modified carbon nanotubes were separated from the acid by decantation and washed several times with distilled water. Carbon nanotubes modified with carboxylic acid groups were suspended in amounts of up to 1% by weight in butanediol. The suspension was sonicated 5 times for 2 minutes with a Branson Sonifier W-450 D (immersion depth of the tip: 1-1.5 cm). The suspension thus formed was transferred as completely as possible to a two-necked flask with septum, stirrer, water separator, reflux condenser and bubble counter. Based on the mass of the suspension, a 5% molar deficit of the anhydride component, in this case maleic anhydride, was added thereto. The suspension was heated to 8O ⁰ C with stirring. The suspension was stirred for 3 h at this temperature. Nitrogen was passed through the suspension for one hour during this time. It was then heated to 100 ⁰ C and stirred for 18 h. It was then heated to 19O ⁰ C and stirred for a further 6 h. During this time, 1-1.2 ml of water separated from the water separator. The suspension could now be cooled. It is recommended to store in the freezer.

For further processing, the polyester was heated to 140 ⁰ C. At this temperature, distilled styrene (in the molar ratio 1: 1 to the anhydride component) was added with vigorous stirring. The mixture was stirred for 1 minute at this temperature and then cooled to room temperature as quickly as possible. The dispersion is then liquid enough to be further processed. It was admixed with 4% by weight (based on the total mass of the suspension incl. Vinyl component) of dibenzoyl peroxide, stirred briefly and poured into Teflon molds to produce the test specimens. The molds were placed in a desiccator, the closed rinsed for 3 minutes with nitrogen and then H was placed in the oven at 80 ⁰ C for 16 h. The finished specimens were lifted by gentle lifting with a spatula and removed from the Teflon molds. Table 1:

Sample Percent Weighing mod Weighing Weighing Weighing Weighing

MWCNTs MWCNTs Diol Comp Acid Anh. Styrene DBPO

1 0 wt% O mg 1 1.83 g 12.25 g 13.02 g 1.48 g

2 0.01% by weight 2.4 mg 11.5 g 1 1.9 g 12.64 g 1.44 g

3 0.1% by weight 24 mg 10.46 g 10.86 g H, 53 g 1.32 g

4 1% by weight 240 mg 8.0 g 8.28 g 8.8 g 1.0 g

Example 2 (comparative experiment).

Analogously to Example 1, a sample was prepared which incorporated the non-modified Köhlenstoffhanoröchen Baytubes C 150 P incorporated. The composition can be taken from Table 2.

Table 2:

Sample Percent Weighed Weighed Weighed Weighed

MWCNTs MWCNTs Diolkomp. Säureanh. Styrene DBPO

0.1% by weight 24 mg 10.46 g 10.86 g H, 53 g 1.32 g Example 3

The tensile yield strength was tested on the tensile drawing machine from Zwick based on DIN 53504. (Force transducer 500 N, Wegaufhehmer: traverse, temperature: room temperature, determination of the film dimensions with caliper). The results are shown in Tab.3.

Table 3:

Sample percent modified percent unmodified tensile strength of the sample

MWCNTs MWCNTs

1 0% 5.71 N / mm ²

2 0.01% 29.4 N / mm ² 3 0.1% 24.3 N / mm ² 4 1% 17.5 N / mm ²

0.1% 17.5 N / mm ²

In comparison with the unsaturated polyester resins with unmodified CNT (Example 5) as a resin additive, the unsaturated polyester resins with modified CNT show a significantly higher tensile strength in the standard test.

Example 4

The fracture behavior of the samples was investigated in a 3-point bending test on an Instron 5566 instrument. The test speed was 5 mm / min. The run distance was 20 mm. The overlay / finned diameter was 10 mm and 5 mm, respectively. The results are summarized in Tab. 4. Table 4:

Sample (example)

Flexural modulus [MPa] 525 1314 1328 1102 642

Bending strength [MPa] 36.5 76.0 72.2 57.5 42.4

Bending strain at [%] 12.0 7.7 7.9 11.2

flexural strength

The bending test shows a comparatively much higher flexural strength of unsaturated polyester resins with modified CNT as additive to unsaturated polyester resins with unmodified CNT as additive.

Claims

claims

1. Reaction resin based on an unsaturated polyester, one or more free-radically curable vinyl compounds, polymerization initiator and carbon nanotubes, characterized in that the carbon nanotubes are covalently bonded to the unsaturated polyester.

2. Reaction resin according to claim 1, characterized in that the unsaturated polyester from units of

a) α, ß-unsaturated acid components

b) one or more polyhydric alcohols and

c) modified carbon nanotubes containing one or more

Carrying carboxylic acid or alcohol groups is constructed.

3. Reaction resin according to claim 1 or 2, characterized in that the free-radically curing vinyl compound is at least one compound selected from the series: styrene, α-methylstyrene, vinyltoluene, methyl methacrylate, vinyl acetate, diallyl phthalate and / or diallyl isophthalate.

4. Reaction resin according to claim 3, characterized in that the resin contains 5 to 70 wt .-%, preferably 30 to 60 wt .-%, free-radically curing vinyl compound.

5. Reaction resin according to one of claims 1 to 4, characterized in that the unsaturated polyester from at least one α, ß-unsaturated acid component from the series: Citracon-, Fumar-, Itacon-, Mesacon- and maleic acid or their anhydrides or

Alkyl esters, preferably fumaric acid, maleic acid and maleic anhydride, is constructed.

6. Reaction resin according to one of claims 1 to 5, characterized in that the content of Kohlenstoffhanoröhrchen is at most 3 wt.%, Preferably at most 1 wt.%, Particularly preferably at most 0.2 wt.% And most preferably at most 0.05 wt .%.

7. Reaction resin according to one of claims 2 to 6, characterized in that the polyhydric alcohols are selected from the series: linear and / or branched aliphatic and / or cycloaliphatic and / or aromatic diols and / or polyols, in particular ethylene glycol, 1,2 and / or 1,3-propanediol, 1,2- and / or 1,4-butanediol, 1,3-butylethylpropanediol, 1,3-methylpropanediol, 1,5-pentanediol, 1,6-haxandiol, Diethylene, triethylene, tetraethylene glycol, cyclohexanedimethanol, glycerol, neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, bisphenol A, bisphenol B, bisphenol C, bisphenol F, neobornylene glycol, 1,4-benzyldimethanol and 1,4-benzyldiethanol, most preferably butanediol.

8. Reaction resin according to one of claims 2 to 7, characterized in that the carbon nanotubes are functionalized with oxygen-containing groups from the series -OH and -COOH, which at least partially arise in the covalent bond to the polyester.

9. Reaction resin according to one of claims 1 to 8, characterized in that the proportion of functional groups -OH and / or -COOH of the carbon nanotubes at least

5 mol%, preferably at least 10 mol%.

10. Reaction resin according to one of claims 1 to 9, characterized in that the resin contains 0.1 to 4 wt .-%, preferably 0.2 to 2 wt .-% polymerization initiator.

11. Reaction resin according to one of claims 1 to 10, characterized in that the resin 20 to 90 wt .-%, preferably 30 to 80 wt .-%, particularly preferably 50 to 75? Wt .-% unsaturated polyester with covalently bound Kohlenstoffhanoröhrchen contains.

12. A process for the preparation of the reaction resin according to claims 1 to 11, characterized in that carbon nanotubes are functionalized by one or more carboxylic acid or alcohol groups by oxidation, the functionalized carbon nanotubes, in one or more polyhydric alcohols, in particular in a diol are dispersed, with a unsaturated acid component, in particular maleic acid, fumaric acid or maleic anhydride, mixed and condensed to form an unsaturated polyester, the functionalized carbon nanotubes being covalently bonded and one or more vinyl monomers selected from the group consisting of: styrene, methylstyrene,

Methyl methacrylate, vinyl acetate, diallyl phthalate and diallyl isophthalate and a radical initiator added.

14. The method according to claim 12, characterized in that the dispersion of the carbon nanotubes is supported by means of ultrasound irradiation and the condensation is effected by water removal at elevated temperature.

15. Application of the reaction resin according to claims 1 to 11 for the production of moldings, for coatings, as foams and as fillers and adhesives.