DE19929029A1 - Novel alkoxysilane group containing piperazinone derivatives are useful as additives for lacquers, coatings, adhesives and sealants, preferably those that are cross-linked via silane polycondensation - Google Patents

Abstract

Novel alkoxysilane group containing piperazinone derivatives are claimed. Alkoxysilane group containing piperazinone derivatives are of formula (I). R, R' = 1-12C alkyl; X, Y, Z = 1-4C alkyl or 6C aryl where at least one of X, Y, Z is 1-4C alkoxy; n = 2-4 An Independent claim is included for a process for the preparation of (I) by mixing an equimolar quantity of an N-aminoethylaminoalkoxysilane of formula H2NCH2CH2NH(CH2)nSi(X)(Y)Z (II) with a maleic or fumaric acid ester of formula RO(O)CH=CHC(O)OR<1> (III) at 0-140 deg C.

Description

The present invention relates to new alkoxysilane-functional piperazinonderi vate, a process for their preparation and their use as an additive in sealing substances, adhesives, paints or coating agents.

Hydrolyzable organofunctional silanes are important auxiliary substances in the formulation Sealants, varnishes or coating agents. An overview of The use of such compounds in the paint industry is found, for example in H. Kittel, Handbook of Lacquers and Coatings, S. Hirzel Verlag Stuttgart, 2. Edition, 1998. Especially for all systems that have a silane polycondensation cross-linking, amino-functional silanes play an important role, both as detention mediator as well as cocatalyst your curing. Having amino groups Alkoxysilanes are e.g. B. described in J. Org. Chem. 36 (1971), p. 3120, DE-A 11 52 95, 12 71 712, 21 61 716, 24 08 480, 25 21 399, 27 49 316 or US-A 2,832,754, 2,971,864 or 4,481,364.

In the case of the amino-functional silanes, it is generally important that the compounds on the one hand, have strongly polar aminic groups which have good substrate adhesion convey. On the other hand, the amino-functional silanes must not be too high have catalytic activity so that they can also be used in larger quantities are what is always necessary when adhering to problematic surfaces which is required. When using larger amounts of aminosilanes of the state In technology, there is often a large catalytic activity of the amino silanes to storage stability problems.

The object of the present invention was therefore to develop new amino-functional silanes To provide good adhesion to various substrates and also in high Dosage can be applied easily. This task was accomplished with the Alkoxysilane-functional piperazine probes provided according to the invention rivaten solved.  

The invention relates to piperazinone derivatives of the general structural formula (I) containing alkoxysilane groups

in which
R represents a linear or branched alkyl radical having up to 12 carbon atoms,
X, Y and Z represent identical or different C ₁ -C ₄ alkyl or C ₆ aryl radicals, with the proviso that at least one of these radicals represents a C ₁ -C ₄ alkoxy group and
n stands for the number 2, 3 or 4.

The present invention also relates to a process for the preparation of alkoxysilane-functional piperazinone derivatives of the formula (I)

in which
R represents a linear or branched alkyl radical having up to 12 carbon atoms,
X, Y and Z represent identical or different C ₁ -C ₄ alkyl or C ₆ aryl radicals, with the proviso that at least one of these radicals represents a C ₁ -C ₄ alkoxy group and
n represents the number 2, 3 or 4,
characterized in that N-aminoethylaminoalkylalkoxysilanes of the general formula (II)

in which X, Y, Z and n have the meaning given for formula (I), with maleic and / or fumaric acid esters of the general formula (III)

ROOC-CH = CH-COOR '(III),

in which
R and R 'independently of one another represent a linear or branched alkyl radical having up to 12 carbon atoms,
be implemented.

In the above formulas, n stands for the number 2, 3 or 4, preferably 3. X, Y and Z independently of one another represent alkyl or alkoxy radicals with 1 to 4 carbon atoms, with the proviso that at least one of the radicals for one Alkoxy radical; preferably all radicals X, Y, Z are methoxy or ethoxy leftovers. R and R 'represent the same or different alkyl radicals with 1 to 12 carbons atoms, preferably identical residues with 1 to 4 carbon atoms.

Examples of suitable N-aminoethylaminoalkylalkoxysilanes are N-aminoethyl 3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyl-triethoxysilane, N- Aminoethyl-3-aminopropyl-methyldimethoxysilane or N-Aminoethyl-3-aminopro pyl-methyldiethoxysilane.

Examples of suitable maleic or fumaric acid esters are maleic acid dimethyl esters, diethyl maleate, dibutyl maleate, dioctyl maleate, Maleic acid didodecyl ester and the corresponding fumaric acid esters. Maleic acid Dimethyl esters, maleic acid diethyl ester and maleic acid dibutyl ester are preferred applicable.

The reaction of the maleic or fumaric acid esters of the formula (III) with the N-ethyl aminoalkylalkoxysilanes of the formula (II) take place within a temperature range from 0 to 140 ° C, preferably 40 to 100 ° C, the proportions in the Usually selected so that the starting compounds in a molar ratio of about 1: 1 can be used.

During the reaction, there is first an addition of the maleic or fumaric acid ester to the NH ₂ group of the aminosilane in the sense of DE-A 42 37 468, followed by a cyclocondensation reaction to give the piperazinone derivative with cleavage of the alcohol R-OH or RAW.

The reaction can be carried out in bulk or in the presence of solvents such as. B. Dioxane can be carried out. The use of solvents is, however, little  ger preferred. Of course, mixtures of different N-ethyl can aminoalkylalkoxysilanes with mixtures of fumaric and / or maleic esters be implemented.

The alcohol R-OH or R'-OH formed in the cyclocondensation reaction is generally removed from the reaction mixture by distillation. The fiction Piperazinone derivatives of the formula (I) which are functional with alkoxysilane are colorless Liquids that are so high after distilling off the alcohol R-OH or R'-OH Purity arise that a distillative workup is generally not necessary.

Another object of the invention is the use of the invention Piperazinone derivatives of the formula (I) containing alkoxysilane groups as additives and / or additives to paints, coatings, adhesives and sealants, preferably those that crosslink via a silane polycondensation.

The alkoxysilyl-functional piperazinone derivatives according to the invention are worthwhile full additives for the production of paints, coatings, sealing materials lien and adhesives. Because of their chemical structure, chemical coupling to inorganic fillers and pigments via the Alkoxysilyl groups, on the other hand the polar piperazinone residue gives a good one Adhesion to various substrates such as plastic, metal, mineral Substrates or wood. Especially in systems with a silane polycondensation sation crosslink such as silicones or alkoxysilyl-functional poly urethanes, the alkoxysilyl-functional piperazinone derivatives according to the invention can be used advantageously. In these systems, the Ver Bonds not only have the role of an adhesion promoter but also have one particularly favorable catalytic activity. In systems that have a silane polycon crosslink densation can comparatively large amounts of the invention Connections can be used without causing problems in storage stability is coming.  

Examples

example 1

1 mol of N-aminoethyl-3-aminopropyltrimethoxysilane is initially introduced at a temperature of 50.degree. Then 1 mol of dimethyl maleate is added dropwise with stirring, the temperature rising to 60.degree. When the dropwise addition is complete, the mixture is stirred at 60 ° C. for 10 hours and then 1 mol of methanol is distilled off under slightly reduced pressure. The reaction product is a pale yellow colored liquid with a GC purity of 95%. The band for the C = O vibration of the piperazinone ring appears at 1645 cm ^{-1 in the} IR spectrum. The band for the C = O vibration of the methyl ester residue appears at 1735 cm ^-1 . In the mass spectrum one observes the Polekülpeak at m / z = 334. In the 1H-NMR spectrum one observes the singlet for the methoxy protons of the ester residue at 3.69 ppm, the protons of the trimethoxysilyl group give rise to a singlet at 3.56 ppm.

Example 2

The procedure is as described in Example 1, but using diethyl maleate instead of dimethyl maleate. 1 mol of ethanol is distilled off under reduced pressure. The reaction product is a pale yellow colored liquid with a GC purity of 92%. The band for the C = O vibration of the piperazinone ring appears at 1650 cm ^{-1 in the} IR spectrum. The band for the C = O vibration of the ethyl ester residue appears at 1740 cm ^-1 . The Polekülpeak is observed in the mass spectrum at m / z = 348.

Example 3

1 mol of N-aminoethyl-3-aminopropyl-methyldimethoxysilane is initially introduced at a temperature of 50.degree. Then 1 mol of diethyl maleate is added dropwise with stirring, the temperature rising to 60.degree. When the dropwise addition is complete, the mixture is stirred at 60 ° C. for 10 hours and then 1 mol of ethanol is distilled off under slightly reduced pressure. The reaction product is a pale yellow colored liquid with a GC purity of 93%. The band for the C = O vibration of the piperazinone ring appears at 1640 cm ^{-1 in the} IR spectrum. The band for the C = O vibration of the ethyl ester residue appears at 1728 cm ^-1 . The Polekülpeak is observed in the mass spectrum at m / z = 332.

Example 4 Production of a sealant based on an alkoxysilyl end group Polyurethane

2000 g of a polyether diol of OH number 28, prepared by propoxylation of Propylene glycol and subsequent ethoxylation of the propoxylation product (PO / EO ratio = 80:20) with 155.4 g of isophorone diisocyanate at 70 ° C  with the addition of 0.02 g of dibutyltin dilaurate until the theoretical is reached NCO content of 0.78% prepolymerized. After cooling to 60 ° C, dropwise 140.4 g of diethyl N- (3-trimethoxysilylpropyl) aspartate (prepared according to EP-A 596 360, Example 5) rapidly and stirred until no isocyanate band in the IR spectrum there is more to see. The resulting alkoxysilyl-terminated polyurethane prepolymer has a viscosity of 76000 mPas (23 ° C).

The following components are processed into a ready-to-use sealant in a commercially available planetary mixer:

36.4 parts by weight of alkoxysilyl-terminated polyurethane
12.9 parts by weight of diisoundecyl phthalate (plasticizer)
0.02 part by weight of dibutyltin bis-acetoacetonate (10% dissolved in solvent naphtha 100)
1.50 parts by weight of vinyl trimethoxysilane
46.2 parts by weight of chalk (type: Socal U1S2)
1.40 parts by weight of Disparlon® NVG8403 S (thixotropic agent from Kusumoto Chem. Ltd.)

The mixture is dispersed for 10 minutes at a pressure of 100 mbar, the internal temperature rising to 60 ° C. Then be

3.0 parts by weight of acoxysilyl-functional piperazinone derivative from Example 1

added and at a pressure of 100 mbar by stirring for 10 minutes is working. The sealant produced in this way shows excellent stability, adheres to almost all substrates and hardens with a skin formation time of 30 Minutes off.  

The product is filled into a commercially available cartridge and stored at 50 ° C. After a storage period of 90 days, the product can still be used without any problems work and shows unchanged product properties.

The following mechanical properties were determined:

Tensile strength: 2.8 N / mm ² (DIN 53504)
Elongation at break: 315% (DIN 53504)
Tear resistance: 6.0 N / mm (DIN 53515)
Shore A hardness: 40

Claims (5)

1. Piperazinone derivatives of the general structural formula (I) containing alkoxysilane groups
in which
R represents a linear or branched alkyl radical having up to 12 carbon atoms,
X, Y and Z represent identical or different C ₁ -C ₄ alkyl or C ₆ aryl radicals, with the proviso that at least one of these radicals represents a C ₁ -C ₄ alkoxy group and
n stands for the number 2, 3 or 4. 2. piperazinone derivatives containing alkoxysilane groups according to claim 1, characterized in that X, Y and Z each represent methoxy radicals or Ethoxy residues stand. 3. Process for the preparation of piperazinone derivatives containing alkoxysilane groups according to claim 1, characterized in that within a temperature range from 0 ° C to 140 ° C approximately equimolar amounts of N-aminoethylaminoalkoxysilanes of the general formula (II)
in which X, Y, Z and n have the meaning given for formula (I) in claim 1,
with maleic and / or fumaric acid esters of the general formula (III)
ROOC-CH = CH-COOR '(III),
in which
R and R 'independently of one another represent a linear or branched alkyl radical having up to 12 carbon atoms,
implements. 4. Use of the piperazinone derivatives containing alkoxysilane groups according to claim 1 as an additive in paints, coatings, adhesives and Sealing compounds. 5. Use of the piperazinone derivatives containing alkoxysilane groups according to claim 1 as an additive in paints, coatings, adhesives and Sealants that crosslink via silane polycondensation.