DE102004024195A1 - Carbodiimides containing silane groups - Google Patents

Abstract

Carbodiimide containing the following structure: DOLLAR F1 with the following meanings for n, R¶1¶, R¶2¶, R¶3¶, R¶4¶ and R¶5¶: DOLLAR A n: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, DOLLAR AR¶1¶: aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched-chain radical, DOLLAR AR¶2¶: aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched-chain radical, DOLLAR AR¶3¶: methyl, ethyl, -O-CH¶3¶, -O- CH¶2¶-CH¶3¶, -O-CH (CH¶3¶) ¶2¶, -OC (CH¶3¶) ¶3¶ or -O-CH¶2¶-CH¶2¶-O -CH¶3¶ DOLLAR AR¶4¶: methyl-, ethyl, -O-CH¶3¶, -O-CH¶2¶-CH¶3¶, -O-CH (CH¶3¶) ¶2¶ , - OC (CH¶¶¶) ¶3¶ or -O-CH¶2¶-CH¶2¶-O-CH¶3¶ DOLLAR AR¶5¶: methyl-, ethyl, -O-CH¶3¶ , -O-CH¶2¶-CH¶3¶, -O-CH (CH¶3¶) ¶2¶, -OC (CH¶3¶) ¶3¶ or -O-CH¶2¶-CH¶ 2¶-O-CH¶3¶.

Description

mit den folgenden Bedeutungen für n, R₁, R₂, R₃, R₄ und R₅:
n: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 oder 20, bevorzugt 2 bis 8, besonders bevorzugt im Mittel 4 bis 6,
R₁: aliphatischer, cycloaliphatischer, araliphatischer oder aromatischer, gegebenenfalls substituierter gegebenenfalls verzweigtkettiger Rest, bevorzugt Alkylenrest mit 1 bis 20, bevorzugt 2 bis 10, besonders bevorzugt 2 bis 4 Kohlenwasserstoffatomen,
R₂: aliphatischer, cycloaliphatischer, araliphatischer oder aromatischer, gegebenenfalls substituierter gegebenenfalls verzweigtkettiger Rest, bevorzugt Alkylenrest mit 1 bis 20, bevorzugt 2 bis 10, besonders bevorzugt 2 bis 4 Kohlenwasserstoffatomen,
R₃: Metyhl-, Ethyl, -O-CH₃, -O-CH₂-CH₃, -O-CH(CH₃)₂, -O-C(CH₃)₃ oder -O-CH₂-CH₂-O-CH₃, bevorzugt -O-CH₃ oder -O-CH₂-CH₃, besonders bevorzugt -O-CH₃,
R₄: Metyhl-, Ethyl, -O-CH₃, -O-CH₂-CH₃, -O-CH(CH₃)₂, -O-C(CH₃)₃ oder -O-CH₂-CH₂-O-CH₃, bevorzugt -O-CH₃ oder -O-CH₂-CH₃, besonders bevorzugt -O-CH₃,
R₅: Metyhl-, Ethyl, -O-CH₃, -O-CH₂-CH₃, -O-CH(CH₃)₂, -O-C(CH₃)₃ oder -O-CH₂-CH₂-O-CH₃, bevorzugt -O-CH₃ oder -O-CH₂-CH₃, besonders bevorzugt -O-CH₃.The invention relates to carbodiimides containing the following structure:

with the following meanings for n, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ :
n: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 or 20, preferably 2 to 8 , more preferably on average 4 to 6,
R ₁ : aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted optionally branched-chain radical, preferably alkylene radical having 1 to 20, preferably 2 to 10, particularly preferably 2 to 4, hydrocarbon atoms,
R ₂ : aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted optionally branched-chain radical, preferably alkylene radical having 1 to 20, preferably 2 to 10, particularly preferably 2 to 4, hydrocarbon atoms,
R ₃ : Metyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O-CH ₂ -CH ₂ - O-CH ₃ , preferably -O-CH ₃ or -O-CH ₂ -CH ₃ , particularly preferably -O-CH ₃ ,
R ₄ : Metyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O-CH ₂ -CH ₂ - O-CH ₃ , preferably -O-CH ₃ or -O-CH ₂ -CH ₃ , particularly preferably -O-CH ₃ ,
R ₅ : methyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O-CH ₂ -CH ₂ - O-CH ₃ , preferably -O-CH ₃ or -O-CH ₂ -CH ₃ , more preferably -O-CH ₃ .

Of Furthermore, the invention relates to mixtures comprising the carbodiimides according to the invention and at least one compound from the following group: polyurethanes, having the ester structures, polyethylene and / or butylene terephthalate, Polyether esters, polyester amides, polycaprolactones, unsaturated polyester resins, Polyamides, in particular containing thermoplastic polyurethanes the carbodiimides of the invention and preferably ester structures. Under the term "silane groups" are used in this Scripture understood in particular silicon-organic groups.

organic Carbodiimides are known and are used, for example, as Stabilizer against the hydrolytic degradation of ester groups Compounds, for example polyaddition and polycondensation such as. Polyurethanes. Carbodiimides may be well known Process be prepared, for example by the action of basic catalysts on mono- or polyisocyanates with elimination of carbon dioxide. Suitable catalysts are e.g. heterocyclic, phosphorus bound containing compounds, metal carbonyls, phospholines, phospholens and phospholidines and their oxides and sulfides.

such Carbodiimides, their preparation and their use as stabilizers against the hydrolytic cleavage of polyester-based plastics are used e.g. described in DE-A 4 318 979, DE-A 4 442 724 and EP-A 460 481.

From the prior art is also known to modify carbodiimides by alkoxysilanes. Thus, EP-A 969 029, EP-A 785 222, EP-A 507 407, EP-A 1 162 237 and US Pat US 4,118,536 the preparation of carbodiimides having alkoxysilane end groups.

The The object of the present invention was improved carbodiimides as stabilizers against the hydrolytic cleavage of plastics based on polyester to develop the optimal incorporation in the starting components of the plastics or in the plastics themselves and also the dynamic and static properties the plastics, in particular polyurethane elastomers, not adversely affect. A special goal was the Property profile of the plastics to be stabilized, in particular of the thermoplastic polyurethane also under conditions in which usually Hydrolysis occurs to get.

These Task could be solved by the carbodiimides shown above.

Purely statistically, the hydrolytic degradation of a polyester a molecule by splitting two molecules. This is accompanied by a corresponding molar mass loss. at Use of the carbodiimide occurs by trapping the acidic Polymer residue to a combination of these two molecules. The Problem of molecular weight reduction, however, is not solved. The particular advantage of the carbodiimides of the invention is both in their outstanding effectiveness as hydrolysis stabilizers as well as in their ability to talk about the Siloxane groups at the end of the carbodiimide crosslinks and thus higher Build molecular weights in the polymer. This particular advantage comes especially in termoplastischen plastics, preferably thermoplastic Polyurethane particularly advantageous for wearing.

By The link from silane groups over the urea group to the carbodiimide is with the carbodiimides of the invention by a simple and economical manufacturing process a very good networking capacity provided a significant molecular weight in the Polymer can cause and thus a high property profile of Polymers ensures.

• • Leicht herstellbar
• • Ohne Nebenreaktionen in TPU einarbeitbar
• • Niedrige Viskositäten bei Verarbeitungstemperatur (60°C)
• • Pumpfähig bei Raumtemperatur
• • Lagerstabil
• • Wirksam als Hydrolyseschutzmittel, insbesondere wenn katalysatorfrei, d.h. mit deutlich reduziertem Gehalt z.B. an Phospholen-oxid
• • Geringe Flüchtigkeit
• • Kostengünstig
• • Reaktion in Masse, d.h. ohne Lösungsmittel

In addition, the carbodiimides according to the invention have the following advantages:

• • Easy to produce
• • Can be used without side reactions in TPU
• • Low viscosities at processing temperature (60 ° C)
• • Pumpable at room temperature
• • Shelf life
• • Effective as a hydrolysis protection agent, especially when catalyst-free, ie with significantly reduced content, for example, of phosphole oxide
• • Low volatility
• • Cost effective
• • Reaction in bulk, ie without solvent

• • Verbesserte hydrolytische Beständigkeit bei Lagerung in Wasser bei 80°C
• • Verbesserung (Erhöhung) der Zugfestigkeit und Reißdehnung bei Lagerung unter Wasser
• • Vernetzung der Siloxangruppen in-situ bei Anwendung unter feuchten Bedingungen, d.h. entfall des zusätzlichen Arbeitsschrittes der Vernetzung
• • Verringerung der Quelleigenschaften
• • Erhöhung der Wärmeformbeständigkeit
• • Erhöhung der HDT
• • Erhöhung des E-Modlus
• • Erhöhung der Vicat-Temperatur

The TPUs produced with the carbodiimides according to the invention have the following advantages over conventional carbodiimides:

• • Improved hydrolytic stability when stored in water at 80 ° C
• • improvement (increase) in tensile strength and elongation at break when stored under water
• • Crosslinking of the siloxane groups in situ when used under humid conditions, ie without the additional working step of crosslinking
• • Reduction of swelling properties
• • increase the heat resistance
• • increase the HDT
• • Increase the e-modus
• • increase the Vicat temperature

mit der folgenden Bedeutung für n: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 oder 20, bevorzugt 2 bis 8, besonders bevorzugt im Mittel 4 bis 6.The following carbodiimides are preferred:

with the following meaning for n: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 or 20, preferably 2 to 8, more preferably on average 4 to 6.

The Preparation of the carbodiimides of the invention can by commonly known reaction of the isocyanate groups with each other with elimination of carbon dioxide in the presence of conventional Catalysts for this implementation are known and have been described, take place.

For example, the carbodiimides according to the invention can be obtained in such a way that 1,3-bis (1-methyl-1-isocyanatoethyl) benzene is reacted in the presence of catalysts with carbon dioxide cleavage to give carbodiimides and subsequently the isocyanate-containing carbodiimide is reacted with a compound, which has at least one isocyanate group and at least one or two, preferably two, silane groups, preferably trialkoxysilane groups, in the presence of catalysts with elimination of carbon dioxide to give the carbodiimide. The molar ratio of the NCO groups of the isocyanate group-containing carbodiimide to the isocyanate groups of the silane is usually from 10: 1 to 0.2: 1, preferably from 5: 1 to 0.5: 1, particularly preferably 1: 1 to 0.5: 1, in particular 1: 1.

alternative can the carbodiimides of the invention be obtained by reacting 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene in admixture with a compound containing at least one isocyanate group and at least one, preferably a silane group, preferably trialkoxysilane group in the presence of catalysts with release of carbon dioxide converts to carbodiimides.

The Preparation of the carbodiimides of the invention by reacting the isocyanate groups at elevated temperatures, e.g. at temperatures of 50 to 200 ° C, preferably from 150 to 185 ° C, conveniently condensed in the presence of catalysts with elimination of carbon dioxide become. Therefor suitable methods are described, for example, in GB-A-1 083 410, DE-B 1 130 594 (GB-A-851 936) and DE-A-11 56 401 (US-A-3 502 722). As catalysts have proven excellent, e.g. Phosphorus compounds, which are preferably selected are from the group of phospholens, phospholene oxides, phospholidines and phospholine oxides. When the reaction mixture the desired Has content of NCO groups, the polycarbodiimide is usually completed. You can do this the catalysts are distilled off under reduced pressure or by Addition of a deactivator, e.g. Phosphorus trichloride, deactivated become. The polycarbodiimide preparation can also be in the absence or presence of solvents inert under the reaction conditions carried out become.

By suitable choice of the reaction conditions such as the reaction temperature, the type of catalyst and the amount of catalyst and the reaction time of the skilled man in the usual way to adjust the degree of condensation. The course of the reaction can be most easily followed by determining the NCO content. Other parameters such as viscosity increase, color well or CO ₂ evolution can also be used to track the process and control the reaction.

When Diisocyanate is used to prepare the carbodiimides of the invention 1,3-bis (1-methyl-1-isocyanatoethyl) benzene, hereafter referred to as TMXDI used. The TMXDI can used in mixtures with other, generally customary isocyanates are, for example, hexamethylene diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (Isophorone diisocyanate), di (cyclohexyl) methane diisocyanate, trimethylhexamethylene diisocyanate, Dodecane diisocyanate, octane diisocyanate and / or cyclohexane-1,4-diisocyanate. In this case, preferably at least 30 mol% TMXDI mitverwendet.

For incorporation of the silane group (s) into the carbodiimide, ie for reaction with the TMXDI or with the carbodiimide based TMXDI generally known isocyanates, preferably monoisocyanates containing at least one, preferably a silane group can be used. Preferably, the following compound is used, which is available from Osi Specialties:

The carbodiimides according to the invention containing at least one, preferably one to twenty, carbodiimide structures, is particularly preferred the mean degree of condensation (number average), i. the middle Number of carbodiimide structures in the carbodiimides of the invention one to ten, more preferably 2 to 8, especially 4 to 6.

The monocarbodiimides according to the invention and / or oligomeric polycarbodiimides are outstandingly suitable Acceptor for Carboxyl compounds and therefore preferably find use as Stabilizers against the hydrolytic degradation of ester groups Compounds, for example polymers containing ester groups, e.g. Polycondensation products such as thermoplastic Polyesters such as polyethylene and butylene terephthalate, polyether esters, Polyamides, polyesteramides, polycaprolactones and unsaturated polyester resins and polyester esters such as e.g. Block copolymers of polyethylene or butylene terephthalate and polycaprolactone. and polyaddition products, e.g. Polyurethanes, polyureas and polyurethane-polyurea elastomers, contain the ester groups. These ester group-containing compounds are well known. Their starting substances, production processes, Structures and properties are described in manifold ways in the standard literature. Due to the good solubility in the synthesis components for the production of poly urethanes and the good compatibility with the polyurethanes formed, the inventive (poly) carbodiimides are especially as stabilizers against the hydrolytic degradation of polyurethanes, preferably compact or cellular polyurethane elastomers and in particular thermoplastic polyurethanes and cellular or compact elastomers.

The concentration of the carbodiimides of the invention in the polycondensation or polyaddition products containing ester groups to be stabilized is generally 0.05 to 10 wt .-%, before preferably 0.1 to 5 wt .-%, based on the total weight of the mixture. In individual cases, depending on the load of the plastic by hydrolysis, the concentration may be higher.

The usable according to the invention Carbodiimides can by various methods in the ester groups to be stabilized containing products are introduced. For example, the carbodiimides according to the invention with one of the constituent components for the preparation of the polyaddition products, e.g. the polyisocyanates and / or polyhydroxyl compounds for the preparation of polyurethanes, or the carbodiimides can be mixed Reaction mixture for the preparation of polyurethanes are added. According to another procedure, the carbodiimides of the invention the melt of the reacted polyaddition or polycondensation be incorporated. However, it is also possible to use granules of the polyaddition or polycondensation products with the carbodiimides of the invention to coat or powdered, pelleted or granulated carbodiimides according to the invention to mix and in a subsequent production of moldings by Introduce melt extrusion in the plastic masses. For the production of polyurethane cast elastomers and polyester-based TPUs according to a preferred embodiment first the carboxyl-containing polyester polyols for reducing the acid contents with the carbodiimides according to the invention treated and then this, optionally with the addition of more Amounts of carbodiimides, with polyisocyanates, optionally in Presence of additional Auxiliaries and additives, reacted. Next, the carbodiimides of the invention over the Isocyanate component are introduced into the polyurethane. Especially However, the carbodiimides according to the invention then come into play when she is during the usual Packing introduced into the ester group-containing polymer become.

Especially The carbodiimides of the invention are preferred in the preparation of polyurethanes, e.g. cellular, for example microcellular polyurethanes, preferably polyurethane elastomers, in particular thermoplastic Polyurethanes used. The preparation of these polyurethanes, in particular Polyurethane elastomers can by known implementation of conventional Output components, i. Isocyanates, isocyanate-reactive compounds, optionally propellants before given to water and optionally Catalysts, auxiliaries and / or additives in the presence of the carbodiimides of the invention take place. In this case, the carbodiimides according to the invention are preferably added to the component, which contains the propellant, preferably water.

Prefers Thus, processes for the preparation of polyurethanes are preferred thermoplastic polyurethanes preferably by reaction of isocyanates, across from Isocyanate-reactive compounds, optionally blowing agents and optionally catalysts, auxiliaries and / or additives, wherein the reaction in the presence of the carbodiimides of the invention performs.

Next the effectiveness as a stabilizer against hydrolytic degradation ester group-containing polyaddition or polycondensation products or for deacidification of polyesterols which are used for the production of polyester-containing Plastics, especially polyurethane rubbers, can be used are suitable the carbodiimides are e.g. also for the termination of esterification reactions in the production of polyesters, if the desired degree of polycondensation is reached.

use could the thermoplastic according to the invention processable polyurethane elastomers for extrusion, injection molding, calendar articles also for Powder-slush process Find.

Prefers become the carbodiimides invention used in thermoplastic polyurethanes. The present invention therefore also relates to processes for the preparation of Silicon-organic groups, also referred to herein as silane-modified, i.e. Silicon organic groups having thermoplastic Polyurethane and so available crosslinkable TPU, in particular Kabelummantellungen, fibers or hoses, in particular Compressed air hoses, as well as the corresponding, over the silane groups crosslinked products. Moreover, the invention relates Kabelummantellungen, fibers or hoses, in particular compressed air hoses, on the basis of thermoplastic polyurethane, silane-containing, especially siloxane groups, in particular cable sheathings, Fibers or hoses, at the cross-linked thermoplastic polyurethane has a Shore A hardness between 85 and 98 and a Vicat temperature according to DIN EN ISO 306 (10N / 120 K / h) greater than 130 ° C, especially preferably greater than 140 ° C, in particular greater than 145 ° C.

The processing of the TPUs according to the invention, which are usually present as granules or in powder form, to injection and extrusion articles, such as the desired films, moldings, rolls, fibers, linings in automobiles, hoses, cable connectors, bellows, trailing cables, Kabelumman Telungen, seals, belts or damping elements is carried out by conventional methods, such as injection molding or extrusion. Such injection molding and extrusion articles can also be made of compounds containing the TPU according to the invention and at least one further thermoplastic, especially a polyethylene, polypropylene, polyester, polyether, polystyrene, PVC, ABS, ASA, SAN, polyacrylonitrile, EVA, PBT, PET, polyoxymethylene, consist. In particular, the TPU produced according to the invention can be used for the production of the articles presented at the outset.

Prefers one is after the silane-modified thermoplastic polyurethane after spun or tubing fibers, in particular Compressed air hoses extrude and then the thermoplastic polyurethane via the silane groups by means Moisture, where appropriate, a catalyst, the the networking accelerates, is used. The crosslinking reactions over and by the silane groups are familiar to the expert and well known. This networking usually takes place moisture and may be by heat or catalysts known for this purpose, e.g. Lewis acids, Lewis bases, Brönsted acids, Bronsted Bases are accelerated. Preference is given to using as catalyst for the crosslinking prefers by means of moisture acetic acid, organic metal compounds such as titanic acid ester, Iron compounds such as e.g. Iron (III) acetylacetonate, tin compounds, e.g. Tin diacetate, tin dioctoate, tin dilaurate or Zinndialkylsalze aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate or the like a, more preferably tin dilaurate and / or acetic acid.

Example 1:

Preparation of stabilizers according to the invention: Isocyanate-stage

1000 Parts by weight (4.1 mol) of 1,3-bis (1-methyl-1-isocyanatoethyl) benzene with an NCO content of 34.4 wt .-% were in the presence of 2.0 Parts by weight of 1-methyl-2-phospholene-1-oxide solventless to 180 ° C heated and at this temperature under moderate carbon dioxide evolution condensed. After reaching an NCO content of the reaction mixture of 10% by weight, this was a reaction time of about 24 hours required, the carbodiimidization was terminated. The reaction mixture was at 100 ° C cooled.

Example 2: Preparation Stabilizers according to the invention: Carbodiimidization with the isocyanato-siloxane (stabilizer 1)

To 500 g of the compound from Example 1 under vigorous stirring within 10 min 117.9 g Silquest ^® A-Link ^TM 35 silanes added dropwise. The temperature was increased up to 120 ° C and the carbodiimidization up to an isocyanate content of max. 1 wt .-% continued. After reaching an NCO content of the reaction mixture of 1 wt .-%, this a reaction time of about 5 hours was required, the added catalyst and residues of unreacted 1,3-bis (1-methyl-1-isocyanato-ethyl ) distilled off benzene and Silquest ^® A-Link ^TM 35 silanes at a temperature of 190 ° C and under a pressure of 0.2 mbar.

The structure of the isocyanate-containing mixture of mono- and oligomeric polycarbodiimides with siloxane engroups was detected by ¹ H-NMR and IR spectrum.

Example 3: Production of TPU samples

Polyol 1)

• Polyester polyol (butanediol / hexanediol adipate, molecular weight 2000, OH number = 56.1; BASF Aktiengesellschaft)

Polyol 2)

• Polyester polyol (butanediol / ethylene glycol adipate, molecular weight 2000, OH number = 56.1; BASF Aktiengesellschaft)

Elastostab^® H01: polymeres Carbodiimid (Hydrolyseschutzmittel) der Elastogran GmbH
Stabaxol^® 1: monomeres Carbodiimid (Hydrolyseschutzmittel) der Rheinchemie GmbH
Stabilisator 1: Stabilisator hergestellt in Beispiel 1The polyols indicated in Table 1 were mixed at 80 ° C with 1,4-butanediol. Subsequently, the addition of the various hydrolysis stabilizers as listed in Table 1 was carried out with stirring. Table 1

Elastostab® ^® H01: polymeric carbodiimide (hydrolysis stabilizer) Elastogran GmbH
Stabaxol ^® 1: monomeric carbodiimide (Antihydrolysis) of Rhein Chemie GmbH
Stabilizer 1: stabilizer prepared in Example 1

The Glycol mixture was stirred at 80 ° C tempered.

After that were 425 g of 4,4'-MDI (Methylendiphenyldiisocyanat) was added and stirred until the Reaction mixture was homogeneous. Subsequently, the mixture was in poured a flat Teflon dish and at 125 ° C on a hot plate for 10 min annealed. The resulting TPU rind was in a heating cabinet 24 h at 100 ° C annealed. After granulating the casting plates, these were placed on a Injection molding machine processed to 2 mm splash plates. The mechanical Values were determined and are listed in Table 2.

Table 2

Table 3

determination hydrolysis

It were punched from the spray plates S2 specimens, these in glasses (250 and 500 ml) with distilled water and placed in a temperature control cabinet defined temperature (80 ° C) posed. At certain intervals (for example weekly) three specimens were taken. Thereafter, the samples were min. Stored for 30 minutes in standard climate 23/50 and tensile strength and elongation at break certainly.

Measurement of tensile strength [MPa] as a function of time [days] Table 4:

Measurement of elongation at break [%] as a function of time [days] Table 5:

Measurement of tensile strength [MPa] as a function of time [days] Table 6:

Measurement of elongation at break [%] as a function of time [days] Table 7:

Claims (7)

Carbodiimide containing the following structure:

with the following meanings for n, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ : n: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 or 20, R ₁ : aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted optionally branched chain radical, R ₂ : aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted optionally branched-chain Radical, R ₃ : Metyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O-CH ₂ -CH ₂ -O-CH ₃ R ₄ : Metyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O- CH ₂ -CH ₂ -O-CH ₃ R ₅ : Metyl, ethyl, -O-CH ₃ , -O-CH ₂ -CH ₃ , -O-CH (CH ₃ ) ₂ , -OC (CH ₃ ) ₃ or -O-CH ₂ -CH ₂ -O-CH ₃ Carbodiimide containing the following structure:

with the following meaning for n: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 13, 14, 15, 16, 17, 18, 19 or 20. Mixtures containing carbodiimides according to claim 1 or 2 and at least one compound from the following group: Polyurethanes having ester structures, polyethylene and / or butylene terephthalate, polyetheresters, polyesteramides, polycaprolactones, unsaturated Polyester resins, polyamides. Thermoplastic polyurethanes containing carbodiimide according to claim 1 or 2 and preferably ester structures. Process for the preparation of carbodiimides, characterized characterized in that 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene in the presence of catalysts with carbon dioxide cleavage to carbodiimides converts and then the isocyanate group-containing carbodiimide with a compound, the at least one isocyanate group and at least one or two Silane groups, in the presence of catalysts with carbon dioxide cleavage converts to carbodiimide. Process for the preparation of carbodiimides, characterized characterized in that 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene in admixture with a compound containing at least one isocyanate group and at least one silane group, in the presence of catalysts reacted under carbon dioxide release to carbodiimides. Process for the preparation of polyurethanes, preferred thermoplastic polyurethanes preferably by reaction of isocyanates, across from Isocyanate-reactive compounds, optionally blowing agents and optionally catalysts, auxiliaries and / or additives, characterized in that the reaction in the presence of carbodiimides according to claim 1 or 2 takes place.