POLYASPARTIC ACID ESTER COMPOSITIONS WHICH CONTAIN POLYASPARTIC ACID ESTERS WITH PRIMARY AMINO GROUPS AND SMALL AMOUNTS OF FUMARIC ACID DIALKYL ESTERS

Abstract

The present invention relates to polyaspartic acid ester compositions which contain polyaspartic acid esters with primary amino groups and small amounts of fumaric acid dialkyl esters, to a method for preparing same and the use thereof as a reactive component for polyisocyanates in two-component polyurethane systems.

Claims

1. A polyaspartic ester composition comprising one or more polyaspartic esters of the general formula (I) ##STR00021## in which X is an m-valent organic radical, optionally containing one or more heteroatoms obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which comprises further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100 C., R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, m is an integer >1, and one or more polyaspartic esters having a primary amino group that are of the general formula (II) ##STR00022## in which n is m1, X and radicals R1 and R2 have the meanings defined for the polyaspartic esters of the general formula (I), wherein a proportion of the polyaspartic esters of the general formula (II) corresponds to from 4% to 15% of a total GC surface area of the composition measured by gas chromatogram as area-%, wherein the total GC surface areas is a sum of the individual surface areas of the polyaspartic esters of the general formulas (I) and (II) and is equal to 100%, and wherein the composition comprises dialkyl fumarate in a proportion of 0.01 to 1% by weight.

2. A process for producing the polyaspartic ester composition of claim 1 comprising: combining one or more polyaspartic esters of the general formula (I) ##STR00023## in which X is an m-valent organic radical, optionally containing one or more heteroatoms obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which comprises further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100 C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, m is an integer >1, with one or more polyaspartic esters having a primary amino group that are of the general formula (II) ##STR00024## in which n is m1, X and radicals R1 and R2 have the meanings defined for the polyaspartic esters of the general formula (I), produced by reacting polyamines of the general formula (III), ##STR00025## in which X and m have the meaning defined for the polyaspartic esters of the general formula (I), with compounds of the general formula (IV)
R1OOCCHCHCOOR2(IV), in which the radicals R1 and R2 have the meaning defined for the polyaspartic esters of the general formula (I); and removing an unreacted proportion of the compound of the general formula (IV) by distillation, wherein the polyaspartic ester composition comprises a proportion of the polyaspartic ester of the general formula (II) of 4% to 15% of a total GC surface area measured by gas chromatogram as area-%, wherein the total GC surface areas is a sum of the individual surface areas of the polyaspartic esters of the general formulas (I) and (II) and is equal to 100%, and wherein the composition comprises dialkyl fumarate in a proportion of 0.01 to 1% by weight.

3. A two-component polyurethane systems, comprising the polyaspartic ester composition of claim 1 and a reactive component that is reactive towards the polyaspartic ester composition of claim 1.

4. A substrate coated with a polyaspartic ester composition as claimed in claim 1.

5. A prepolymer, comprising a reaction product of the polyaspartic ester composition of claim 1 with a reactive component that is reactive towards the polyaspartic ester composition of claim 1.

Description

EXPERIMENTAL

Raw Materials:

[0197] Vestamin PACM: a mixture of 2,4- and 4,4-diaminodicyclohexylmethane, manufacturer: Evonik

[0198] Desmodur N 3600: a low-viscosity HDI trimer containing approx. 23% NCO and 0.25% free HDI, manufacturer: Covestro

[0199] Desmodur N 3900: a low-viscosity HDI trimer containing approx. 23.5% NCO and 0.25% free HDI, manufacturer: Covestro

[0200] Byk 331: polyether-modified polydimethylsiloxane surface additive, manufacturer: Byk

[0201] Tinuvin 292: a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, a light stabilizer from BASF

[0202] Tinuvin 384-2: benzenepropanoic acid, 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy, C.sub.7-C.sub.9 branched and linear alkyl esters, a light stabilizer from BASF

Methods:

[0203] Diethyl fumarate contents were quantitatively determined using a GC method with internal standard. An Agilent 6890 gas chromatograph with a standard GC capillary (100% polysiloxane phase) and FID detector were used. The injector temperature (split outlet) was 180 C.; helium was used as the carrier gas. The quantitation limit of this method was 300 ppm.

[0204] GC-MS analyses were carried out using an Agilent 6890 gas chromatograph and Agilent 5973 mass spectrum detector with standard ionization (electron impact) at 70 eV, a standard GC capillary (100% polysiloxane phase) and split injection at an injector temperature of 250 C. Evaluation of the gas chromatograms was in area-%.

[0205] All viscosity measurements were carried out using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) in accordance with DIN EN ISO 3219:1994-10.

[0206] NCO contents were determined titrimetrically in accordance with DIN EN ISO 11909:2007-05.

[0207] Hazen color index values were determined on a Lico 400 colorimeter from Hach Lange GmbH,

[0208] Dsseldorf in accordance with DIN EN ISO 6271:2016-05

[0209] Amine values were determined titrimetrically in accordance with EN ISO 9702:1998 (perchloric acid method) with the exception that the results were expressed as the amine value. The amine value in mg KOH/g was calculated according to the following equation:

[00001]$\mathrm{Amine}.Math..Math.\mathrm{value}=\frac{\left(a-b\right)5.61}{W}$

a=volume of perchloric acid consumed in the main test, in milliliters, c=0.1 mol/l;
b=volume of perchloric acid consumed in the blank test, in milliliters, c=0.1 mol/l;
W=weight of sample, in grams

[0210] Flow times were determined in accordance with DIN EN ISO 2431:2012-03, with the exception that a DIN 4 flow cup was used. The pot life was defined as the time corresponding to twice the flow time.

[0211] Drying determinations were carried out in accordance with DIN EN ISO 9117-5:2012-11.

[0212] For the determination of reactivity, the following gel-time measurement method was developed: The feedstocks (total amount 10 g) were weighed into a beaker and mixed for 15 seconds at 3000 rpm in a Speedmixer. Then, using a bent paperclip or a disposable pipette, the time taken for the mixture to be drawn into threads or to become solid was determined with a stopwatch.

Example 1 (Comparative Example)

[0213] Polyaspartic ester commercially available from Covestro under the name Desmophen NH 1420.

[0214] Material data:

TABLE-US-00001 Monoamine of the formula (II) (GC-MS): 4.0% Diethyl fumarate (GC) 2.9% by weight Viscosity 1220 mPas Color index 27 APHA Amine value 201 mg KOH/g

Example 2 (Comparative Example)

[0215] 341.8 g of Vestamin PACM was initially charged at 23 C. under dry nitrogen, with stirring. To this was added dropwise 839.4 g of diethyl maleate, ensuring that the temperature did not rise above 60 C. At the end of the addition, the temperature was adjusted to 45 C. and the mixture was stirred for one hour at 45 C. The mixture was then stored at 23 C. for 8 weeks. The content of diethyl fumarate after storage was 0.04% by weight. A light-colored product was obtained that had the following material data:

TABLE-US-00002 Monoamine of the formula (II) (GC-MS): 65.8% Diethyl fumarate (GC) 0.04% by weight Viscosity 690 mPas Color index 16 APHA Amine value 293 mg KOH/g

Example 3 (Comparative Example)

[0216] 341.8 g of Vestamin PACM was initially charged at 23 C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60 C. At the end of the addition, the temperature was adjusted to 45 C. and the mixture was stirred for one hour at 45 C. The mixture was then stored at 23 C. for 24 hours. The content of diethyl fumarate after storage was 11.5% by weight. Diethyl fumarate was then distilled off at 120 C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

TABLE-US-00003 Monoamine of the formula (II) (GC-MS): 25.4% Diethyl fumarate (GC) 0.05% by weight Viscosity 1330 mPas Color index 8 APHA Amine value 224 mg KOH/g

Example 4

[0217] 341.8 g of P Vestamin PACM was initially charged at 23 C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60 C. At the end of the addition, the temperature was adjusted to 45 C. and the mixture was stirred for 2 hours at 45 C. The mixture was then stored at 23 C. for 7 weeks. The content of diethyl fumarate after storage was 2.7% by weight. Diethyl fumarate was then distilled off at 120 C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

TABLE-US-00004 Monoamine of the formula (II) (GC-MS): 5.3% Diethyl fumarate (GC) 0.08% by weight Viscosity 1810 mPas Color index 19 APHA Amine value 203 mg KOH/g

Example 5

[0218] 341.8 g of Vestamin PACM was initially charged at 23 C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60 C. At the end of the addition, the temperature was adjusted to 45 C. and the mixture was stirred for two hours at 45 C. The mixture was then stored at 23 C. for 30 hours. The content of after storage was 8.62% by weight. Diethyl fumarate was then distilled off at 120 C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

TABLE-US-00005 Monoamine of the formula (II) (GC-MS): 13.2% Diethyl fumarate (GC) <0.03% by weight Viscosity 1650 mPas Color index 5 APHA Amine value 213 mg KOH/g

Example 6

[0219] 341.8 g of Vestamin PACM was initially charged at 23 C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60 C. At the end of the addition, the temperature was adjusted to 45 C. and the mixture was stirred for one hour at 45 C. The mixture was then stored at 23 C. for 24 hours. The content of diethyl fumarate after storage was 8.85% by weight. Diethyl fumarate was then distilled off at 120 C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

TABLE-US-00006 Monoamine of the formula (II) (GC-MS): 14.1% Diethyl fumarate (GC) 0.08% by weight Viscosity 1630 mPas Color index 5 APHA Amine value 214 mg KOH/g

[0220] Before performance testing, the reactivity of selected polyaspartic esters was determined by the gel-time measurement method described above.

TABLE-US-00007 TABLE 1 Determination of reactivity by the gel-time measurement method Desmodur Desmodur Desmodur Desmodur Desmodur Feedstock N 3600 N 3600 N 3600 N 3600 N 3600 Sample 4.18 4.88 4.22 4.18 4.18 weight Feedstock Example 1 Example 2 Example 3 Example 5 Example 6 Sample 5.82 5.11 5.78 5.82 5.82 weight Time until: sample can 37 min n.d.* 5 min 49 min 52 min be drawn into threads the sample 65 min n.d.* 7 min 88 min 92 min is solid *Gelation of sample in Speedmixer

[0221] It can be seen from table 1 that the inventive composition comprising polyaspartic esters from examples 5 and 6, despite having a higher content of polyaspartic esters having primary amino groups compared to the commercially available product, does not show a shortened gel time and is therefore suitable for coatings.

Testing in Coatings

[0222] Inventive polyaspartic ester compositions from examples 1 and 5 were tested in coating formulations.

Preparation of a Coating Base

[0223] To the amount of component A shown in table 2 were added the additives and the amount of butyl acetate shown in the table, and the mixture was stirred thoroughly.

Preparation of the Hardener Solution

[0224] To the amount of component B shown in table 2 was added the amount of butyl acetate shown in the table, and the mixture was stirred thoroughly.

[0225] Mixing of the coating base with the hardener and application:

[0226] The coating base described above and the hardener were combined and mixed thoroughly. The mixtures were then each applied with an air gun to coil-coating sheet precoated with black basecoat, flashed off for 10 min at room temperature, and then dried at room temperature and at 60 C. Brilliant, high-gloss coatings with a layer thickness of 50 m were obtained.

[0227] An overview of the coating properties determined for the coatings is shown in table 3.

TABLE-US-00008 TABLE 2 Composition of the coating bases Example 7 Example 8 Example 9 Temperature: 24 C. (inventive) (inventive) (comparative) Air humidity: 48% Component A Example 5 43.77 Example 4 45.25 Example 1 47.24 Byk 331 (10% in BA) 0.08 0.08 0.08 Tinuvin 292 (50% in BA) 0.16 0.17 0.16 Tinuvin 384-2 (50% in BA) 0.33 0.33 0.33 Butyl acetate 21.34 20.00 16.19 Component B Desmodur N 3900 (100%) 29.75 29.42 30.65 Butyl acetate 1.57 1.75 2.35

TABLE-US-00009 TABLE 3 Coating properties of coatings Temperature: 24 C. Example 7 Example 8 Example 9 Relative humidity: 48% Solids content in % 73.4 74.9 81.1 at spray viscosity (calc.) Flow time DIN 4 mm 0 h 17 16 17 (sec) 5 18 17 18 10 19 18 20 15 21 19 24 20 23 20 27 25 27 22 31 30 32 25 40 Drying (min) T 1 13 12 15 RT T 3 27 25 30 T 4 40 40 45 Layer thickness (m) about 50 about 50 about 50 Drying (min) T 1 immediately immediately immediately 30-60 C. T 3 15 15 20 T 4 27 25 30 Layer thickness (m) about 50 about 50 about 50

[0228] Comparison of the coating properties shown in table 3 for the comparison coating (example 9) with those of the inventive coatings (examples 7 and 8) demonstrates that the inventive coatings dry more rapidly while having an unchanged pot life.