WO2005111106A1 - Carbodiimides containing silane groups - Google Patents

Abstract

The invention relates to a carbodiimide containing the structure of formula (I), in which n, R1, R2, R3, R4 and R5 are defined as follows: n represents 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20; R1 represents an aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched-chain group; R2 represents an aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched-chain group; R3 represents methyl-, ethyl, O-CH3, -O-CH2-CH3, -O-CH(CH3)2, -O-C(CH3)3 or -O-CH2-CH2-O-CH3; R4 represents methyl-, ethyl, -O-CH3, -O-CH2-CH3, -O-CH(CH3)2, -O-C(CH3)3 or -O-CH2-CH2-O-CH3; and R5 represents methyl-, ethyl, -O-CH3, -O-CH2-CH3, -O-CH(CH3)2, -O-C(CH3)3 or -O-CH2-CH2-O-CH3.

Description

Carbodiimides containing silane groups

description

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 , particularly preferably on average 4 to 6,

R ^ aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted optionally branched chain radical, preferably alkylene radical with 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 with 1 to 20, preferably 2 to 10, particularly preferably 2 to 4 hydrocarbon atoms,

R 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 , preferably -O-CH ₃ or -O-CH ₂ -CH ₃ , particularly preferably -O-CH ₃ ,

R ₄ : 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 , 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 -0-CH ₂ -CH ₂ - O-CH ₃ , preferably -O-CH ₃ or -O-CH ₂ -CH ₃ , particularly preferably -O-CH ₃ .

The invention further relates to mixtures comprising the carbodiimides according to the invention and at least one compound from the following group: polyurethanes which have ester structures, polyethylene and / or butylene terephthalate, polyether esters, polyester amides, polycaprolactones, unsaturated polyester resins, polyamides, in particular thermoplastic polyurethanes the carbodiimides according to the invention and preferably ester structures. In this document, the term “silane groups” is understood to mean, in particular, organic silicon groups. Organic carbodiimides are known and are used, for example, as a stabilizer against the hydrolytic degradation of compounds containing ester groups, for example polyaddition and polycondensation products such as polyurethanes. Carbodiimides can be prepared by generally known processes, for example by the action of basic catalysts on mono- or polyisocyanates with elimination of carbon dioxide. Suitable catalysts are, for example, heterocyclic compounds containing phosphorus, metal carbonyls, phospholines, phospholenes 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 e.g. described in DE-A 4 318 979, DE-A 4 442 724 and EP-A 460 481.

It is also known from the prior art to modify carbodiimides by alkoxysilanes. For example, EP-A 969 029, EP-A 785 222, EP-A 507 407, EP-A 1 162 237 and US 4 118 536 describe the preparation of carbodiimides which have alkoxysilane end groups.

The object of the present invention was to develop improved carbodiimides as stabilizers against the hydrolytic cleavage of plastics based on polyester, which have an optimal incorporation into the starting components of the plastics or in the plastics themselves and also the dynamic and static properties of the plastics, in particular of polyurethane elastomers, not adversely affect. A particular aim was to maintain the property profile of the plastics to be stabilized, in particular the thermoplastic polyurethane, even under conditions in which hydrolysis usually occurs.

This task could be solved by the carbodiimides described at the beginning.

Statistically, the hydrolytic degradation of a polyester from one molecule by splitting two molecules. This is accompanied by a corresponding loss of molecular weight. When using the carbodiimide, trapping the acidic polymer residue results in a combination of these two molecules. This does not solve the problem of molecular weight reduction. The particular advantage of the carbodiimides according to the invention lies both in their outstanding activity as hydrolysis stabilizers and in their ability to build up crosslinks and thus higher molar masses in the polymer via the siloxane groups at the end of the carbodiimide. This particular advantage is particularly advantageous in thermoplastic plastics, preferably thermoplastic polyurethane. By linking silane groups to the carbodiimide via the urea group, the carbodiimides according to the invention provide a very good crosslinking capacity through a simple and economical production process, which can bring about a clear molecular weight build-up in the polymer and thus ensures a high property profile of the polymer.

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

Easily manufactured Can be incorporated into TPU without side reactions Low viscosities at processing temperature (60 ° C) Pumpable at room temperature Stable in storage Effective as hydrolysis protection agent, especially when free of catalysts, i.e. with a significantly reduced content e.g. on phospholene oxide Low volatility Inexpensive reaction in bulk, i.e. without solvent

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

Improved hydrolytic resistance 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 moist conditions, i.e. Eliminate the additional step of crosslinking Reduce swelling properties Increase heat resistance Increase HDT Increase E-mode Increase Vicat temperature

The following carbodiimides are preferred:

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.

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, preferred 2 to 8, particularly preferably on average 4 to 6.

The carbodiimides according to the invention can be prepared by generally known reaction of the isocyanate groups with one another with elimination of carbon dioxide in the presence of customary catalysts which are known for this reaction and have been described at the beginning.

For example, the carbodiimides according to the invention can be obtained by reacting 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene in the presence of catalysts with elimination of carbon dioxide to give carbodiimides and then the carbodiimide having isocyanate groups 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 carbodiimide having isocyanate groups to the isocyanate groups of silane is usually 10: 1 to 0.2: 1, preferably 5: 1 to 0.5: 1, particularly preferably 1: 1 to 0, 5: 1, especially 1: 1.

Alternatively, the carbodiimides according to the invention can be obtained by mixing 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene in a mixture with a compound which has at least one isocyanate group and at least one, preferably a silane group, preferably trialkoxysilane group has, in the presence of catalysts with carbon dioxide release to carbodiimides.

The preparation of the carbodiimides according to the invention by reacting the isocyanate groups can be carried out at elevated temperatures, e.g. at temperatures from 50 to 200 ° C, preferably from 150 to 185 ° C, advantageously in the presence of catalysts with carbon dioxide elimination. Methods suitable for this 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). The following have proven to be excellent catalysts, e.g. Phosphorus compounds, which are preferably selected from the group of phospholenes, phospholenoxides, phospholidines and phospholinoxides. When the reaction mixture has the desired NCO group content, the polycarbodiimide formation is usually ended. For this purpose, the catalysts can be distilled off under reduced pressure or by adding a deactivator, such as e.g. Phosphorus trichloride can be deactivated. The polycarbodiimide preparation can also be carried out in the absence or presence of solvents which are inert under the reaction conditions.

By a suitable choice of the reaction conditions such as the reaction temperature, the type of catalyst and the amount of catalyst and the reaction time, the specialist adjust the degree of condensation in the usual way. The easiest way to follow the course of the reaction is to determine the NCO content. Other parameters such as viscosity increase, color deepening or CO ₂ development can also be used to monitor the process and control the reaction.

1,3-Bis- (1-methyl-1-isocyanato-ethyl) -benzene, hereinafter also referred to as TMXDI, is used as the diisocyanate for the preparation of the carbodiimides according to the invention. The TMXDI can be used in mixtures with other, generally customary isocyanates, 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 - Isocyanate and / or cyclohexane-1,4-diisocyanate. In this case, at least 30 mol% of TMXDI is preferably used.

To insert the silane group (s) into the carbodiimide, i.e. For the reaction with the TMXDI or with the carbodiimide based on TMXDI, generally known isocyanates, preferably monoisocyanates, containing at least one, preferably one, silver group can be used. The following compound, which is available from Osi Specialties, is preferably used:

OCN ^^ Si (OMe),

The carbodiimides according to the invention containing at least one, preferably one to twenty carbodiimide structures, particularly preferably the average degree of condensation (number average), i.e. the average number of carbodiimide structures in the carbodiimides according to the invention one to ten, particularly preferably 2 to 8, in particular 4 to 6.

The monocarbodiimides and / or oligomeric polycarbodiimides according to the invention are outstandingly suitable as acceptors for carboxyl compounds and are therefore preferably used as stabilizers against the hydrolytic degradation of compounds containing ester groups, for example polymers containing ester groups, for example polycondensation products such as thermoplastic polyesters such as polyethylene and butylene terephthalate and polyether esters , Polyamides, polyester amides, polycaprolactones and unsaturated polyester resins and polyester esters such as block copolymers of polyethylene or butylene terephthalate and polycaprolactone. and polyaddition products, for example polyurethanes, polyureas and polyurethane-polyurea elastomers, which contain ester groups. These compounds containing ester groups are generally known. Their starting substances, manufacturing processes, structures and properties are described in a variety of ways in the standard literature. Due to the good solubility in the structural components for the production of poly Urethanes and good compatibility with the polyurethanes formed are the (poly) carbodiimides according to the invention particularly suitable 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 according to the invention in the polycondensation or polyaddition products containing ester groups to be stabilized is generally 0.05 to 10% by weight, preferably 0.1 to 5% by weight, based on the total weight of the mixture. In individual cases, depending on the stress on the plastic due to hydrolysis, the concentration can also be higher.

The carbodiimides which can be used according to the invention can be introduced into the products containing ester groups to be stabilized by various methods. For example, the carbodiimides according to the invention can be combined with one of the structural components for the preparation of the polyadducts, e.g. the polyisocyanates and / or polyhydroxyl compounds for the production of polyurethanes are mixed, or the carbodiimides can be added to the reaction mixture for the production of the polyurethanes. According to another procedure, the carbodiimides according to the invention can be incorporated into the melt of the fully reacted polyaddition or polycondensation products. However, it is also possible to coat granules of the polyaddition or polycondensation products with the carbodiimides according to the invention or to mix them with the pulverized, pelletized or granulated carbodiimides according to the invention and to incorporate them into the plastic materials by melt extrusion in a subsequent production. To produce polyurethane cast elastomers and polyester-based TPUs, in a preferred embodiment, the carboxyl-containing polyester polyols are first treated with the carbodiimides according to the invention to reduce the acid contents and then these, optionally with the addition of further amounts of carbodiimides, with polyisocyanates, optionally in the presence of additional ones Tools and additives, brought to reaction. Furthermore, the carbodiimides according to the invention can be introduced into the polyurethane via the isocyanate component. However, the carbodiimides according to the invention are particularly useful when they are introduced into the polymer containing ester groups during customary packaging.

The carbodiimides according to the invention are particularly preferably used in the production of polyurethanes, for example cellular, for example microcellular polyurethanes, preferably polyurethane elastomers, in particular thermoplastic polyurethanes. These polyurethanes, in particular polyurethane elastomers, can be prepared by known reaction of conventional starting components, ie isocyanates, compounds which are reactive toward isocyanates, optionally blowing agents, before adds water and optionally catalysts, auxiliaries and / or additives in the presence of the carbodiimides according to the invention. The carbodiimides according to the invention are preferably added to the component which contains the blowing agent, preferably water.

Thus, processes for the production of polyurethanes, preferably thermoplastic polyurethanes, preferably by reacting isocyanates, compounds which are reactive toward isocyanates, optionally blowing agents and optionally catalysts, auxiliaries and / or additives are preferred, the reaction being carried out in the presence of the carbodiimides according to the invention.

In addition to being effective as a stabilizer against the hydrolytic degradation of polyaddition or polycondensation products containing ester groups or for deacidifying polyesterols which can be used for the production of polyester-containing plastics, in particular polyurethane rubbers, the carbodiimides are suitable, for example: also to terminate esterification reactions in the production of polyester when the desired degree of polycondensation has been reached.

The thermoplastically processable polyurethane elastomers according to the invention can be used for extrusion, injection molding, calendar articles and for powder slush processes.

The carbodiimides according to the invention are preferably used in thermoplastic polyurethanes. The present invention therefore also relates to processes for producing silicon-organic groups, in this document also as silane-modified, i.e. Thermoplastic polyurethane containing silicon-organic groups and crosslinkable TPU obtainable in this way, in particular cable sheaths, fibers or hoses, in particular compressed air hoses, and the corresponding products crosslinked via the silane groups. In addition, the invention relates to cable sheathing, fibers or hoses, in particular compressed air hoses, based on thermoplastic polyurethane which is crosslinked via silane groups, in particular siloxane groups, in particular cable sheathing, fibers or hoses in which the crosslinked thermoplastic polyurethane has a Shore-A hardness of between 85 and 98 and a Vicat temperature according to DIN EN ISO 306 (10N / 120 K / h) of greater than 130 ° C, particularly preferably greater than 140 ° C, in particular greater than 145 ° C.

The processing of the TPUs produced according to the invention, which are usually present in the form of granules or in powder form, into injection molding and extrusion articles, for example the desired films, moldings, rolls, fibers, linings in automobiles, hoses, cable connectors, bellows, trailing cables, cable jackets, seals , Belts or damping elements are carried out using customary methods, such as Injection molding or extrusion. Injection molding and extrusion articles of this type can also be made from compounds containing the TPU according to the invention and at least one further thermoplastic, in particular a polyethylene, polypropylene, polyester, polyether, polystyrene, PVC, ABS, ASA, SAN, polyacrylonitrile, EVA, PBT, PET, polyoxy- methylene. In particular, the TPU produced according to the invention can be used to produce the articles shown at the beginning.

The silane-modified thermoplastic polyurethane will preferably be spun into fibers or hoses, in particular compressed air hoses, by generally known methods, and then the thermoplastic polyurethane will be crosslinked via the silane groups by means of moisture, optionally using a catalyst which accelerates the crosslinking. The crosslinking reactions above and through the silane groups are familiar to the person skilled in the art and are generally known. This crosslinking is usually carried out by moisture and can be carried out by heat or catalysts known for this purpose, e.g. Lewis acids, Lewis bases,

Bronsted acids, Bronsted bases are accelerated. Acetic acid, organic metal compounds such as titanium acid esters, iron compounds such as e.g. Iron (III) acetylacetonate, tin compounds e.g. Tin diacetate, tin dioctoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyl tin diacetate, dibutyl tin dilaurate or the like, particularly preferably tin dilaurate and / or acetic acid.

Example 1:

Production of stabilizers according to the invention: isocyanate stage

1000 parts by weight (4.1 mol) of 1,3-bis (1-methyl-1-isocyanato-ethyl) benzene with an NCO content of 34.4% by weight were in the presence of 2.0 Parts by weight of 1-methyl-2-phospholen-1-oxide are heated to 180 ° C. without solvent and condensed at this temperature with moderate evolution of carbon dioxide. When the NCO content of the reaction mixture reached 10% by weight, which required a reaction time of approximately 24 hours, the carbodiimidization was terminated. The reaction mixture was cooled to 100 ° C.

Example 2 Production of Stabilizers According to the Invention: Carbodiimidization with the Isocyanato-Siloxane (Stabilizer 1)

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

The structure of the mixture of mono- and oligomeric polycarbodiimides with siloxane ene groups and containing isocyanate groups was verified by ¹ H-NMR and IR spectra.

Example 3: Preparation 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)

The polyols listed in Table 1 were mixed at 1,40 with butanediol. The various hydrolysis protective stabilizers as listed in Table 1 were then added with stirring.

Table 1

Elastostab® H01: polymeric carbodiimide (hydrolysis protection agent) from Elastogran GmbH Stabaxol® 1: monomeric carbodiimide (hydrolysis protection agent) from Rheinchemie GmbH Stabilizer 1: Stabilizer produced in Example 1 The glycol mixture was heated to 80 ° C. with stirring. Then 425 g of 4,4'-MDI (methylene diphenyl diisocyanate) were added and the mixture was stirred until the reaction mixture was homogeneous. The mixture was then poured into a flat Teflon dish and annealed at 125 ° C. on a hot plate for 10 minutes. The resulting TPU rind was annealed in a heating cabinet at 100 ° C for 24 h. After the mold plates had been granulated, they were processed into 2 mm spray plates on an injection molding machine. The mechanical values were determined and are listed in Table 2.

Table 2

Table 3

Bestimmung Hydrolysebeständigkeit

Determination of resistance to hydrolysis

S2 test specimens were punched out of the spray plates, these were placed in glasses (250 and 500 ml) with distilled water and placed in a temperature control cabinet at a defined temperature (80 ° C.). Three test specimens were removed at certain intervals (e.g. weekly). Then the samples were min. Stored for 30 minutes in standard climate 23/50 and determined tensile strength and elongation at break.

Table 4:

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

Table 5:

Elongation at break [%] as a function of time [days]

Table 6:

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

Tabelle 7:

Table 7:

Elongation at break [%] as a function of time [days]

Claims

claims Carbodiimide containing the following structure:

with the following meanings for n, RR ₂ , R ₃ , R .; 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, Rv: aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched chain residue, R ₂ : aliphatic, cycloaliphatic, araliphatic or aromatic, optionally substituted, optionally branched chain residue, R ₃ : methyl, ethyl, -O-CH _3l -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 : 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 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 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 which have ester structures, polyethylene and / or butylene terephthalate, polyether esters, polyester amides, polycaprolactones, unsaturated polyester resins, polyamides. 4. Thermoplastic polyurethanes containing carbodiimide according to claim 1 or 2 and preferably ester structures. 5. Process for the preparation of carbodiimides, characterized in that 1, 3-bis (1-methyl-1-isocyanato-ethyl) benzene is reacted in the presence of catalysts with elimination of carbon dioxide to give carbodiimides and then the isocyanate group-containing carbodiimide is reacted with a Compound which has at least one isocyanate group and at least one or two silane groups in the presence of catalysts with elimination of carbon dioxide to give the carbodiimide. 6. Process for the preparation of carbodiimides, characterized in that 1, 3-bis (1-methyl-1-isocyanato-ethyl) benzene in a mixture with a compound which has at least one isocyanate group and at least one silane group, in the presence from catalysts with carbon dioxide release to carbodiimides. 7. Process for the production of polyurethanes, preferably thermoplastic polyurethanes, preferably by reacting isocyanates, compounds which are reactive toward isocyanates, optionally blowing agents and, if appropriate, catalysts, auxiliaries and / or additives, characterized in that the reaction in the presence of carbodiimides according to claim 1 or 2 he follows.