Polymer additive and a method for the production thereof

Abstract

The invention relates to a compound of formula (I), characterised by the characteristic signals in the X-ray diffraction powder pattern measured with Cu Kalpha radiation (0.154 nm) at a 2-theta angle of 15.0 and 22.7 with a high intensity, and of 5.0, 11.3, 18.9, 20.8, 21.6 and 23.6 with a medium intensity, as well as to a method for producing the compound of formula (I) by reacting at least one isophthalic acid diester of formula (II) where R1 and R2 are the same or different and stand for an aliphatic group, with two equivalents 4-amino-2,2,6,6-tetramethylpiperidine, in the presence of at least one catalyst from the group of metal alcoholates and at a reaction temperature of between 50 and 150 C.

Claims

1. A compound of the formula (I) ##STR00007## wherein an X-ray powder diffraction pattern of the compound has characteristic signals measured with Cu K.sub.alpha radiation at a 2-theta angle of 15.0 and 22.7 having a high intensity and of 5.0, 11.3, 18.9, 20.8, 21.6 and 23.6 having a moderate intensity.

2. A process for preparing the compound of the formula (I) as claimed in claim 1, comprising reacting at least one isophthalic diester of the formula (II) ##STR00008## wherein R.sup.1 and R.sup.2 are the same or different and are an aliphatic radical, with 2 equivalents of 4-amino-2,2,6,6-tetramethylpiperidine in the presence of at least one catalyst, wherein the at least one catalyst is a metal alkoxide, at a reaction temperature between 50 and 150 C.

3. The process as claimed in claim 2, wherein the metal alkoxide is a compound of the formula (VI) and/or (VII)
XOR.sup.13 (VI)
R.sup.14OYOR.sup.15 (VII) wherein R.sup.14 and R.sup.15 are each the same or different; R.sup.13, R.sup.14 and R.sup.15 are aliphatic radicals each having 1 to 20 carbon atoms; X is an alkali metal; and Y is an alkaline earth metal.

4. The process as claimed in claim 2, wherein the metal alkoxide is sodium methoxide, potassium methoxide, lithium methoxide, sodium ethoxide, potassium ethoxide, lithium ethoxide, sodium n-propoxide, potassium n-propoxide, sodium isopropoxide, potassium isopropoxide, sodium butoxide, potassium butoxide, sodium isobutoxide, potassium isobutoxide, sodium sec-butoxide, potassium sec-butoxide, sodium tert-amoxide, sodium amoxide, potassium amoxide, potassium tert-butoxide or a combination thereof.

5. The process as claimed in claim 2, wherein the metal alkoxide is added to the reaction mixture in amounts of 1 to 20 mol %, based on the isophthalic diester.

6. The process as claimed in claim 2, wherein the reaction is conducted solvent-free and in a reaction apparatus selected from the group consisting of mixers, kneaders and extruders.

7. The process as claimed in claim 6, wherein the reaction mixture, after the addition of the at least one catalyst, is mixed by the kneader, mixer or extruder at the reaction temperature for a period of 10 to 400 minutes.

8. The process as claimed in claim 6, wherein the kneader or mixer is equipped with sigma blades, masticator blades, plowshares, Becker blades, throwing paddles or a combination thereof.

9. The process as claimed in claim 2, wherein the isophthalic diester is dissolved in an excess of the 4-amino-2,2,6,6-tetramethylpiperidine.

10. The process as claimed in claim 2, wherein the isophthalic diester is dissolved together with two equivalents of the 4-amino-2,2,6,6-tetramethylpiperidine and a lipophilic liquid hydrocarbon or a mixture thereof.

11. The process as claimed in claim 2, wherein alcohol formed in the reaction is removed from the reaction mixture.

12. The process as claimed in claim 2, wherein the compound of the formula (I) precipitates out of the reaction mixture in solid form.

13. A polymer additive comprising a compound of the formula (I) as claimed in claim 1.

14. A stabilized polymer comprising a compound of the formula (I) as claimed in claim 1, wherein the stabilized polymer is stabilized against light and heat and has oxygen barrier properties.

15. The polymer additive as claimed in claim 13, wherein the polymer is selected from the group consisting of polyamides, polyesters and EVOH.

Description

EXAMPLES

(1) The products were analyzed by means of .sup.1H NMR spectroscopy at 400 MHz in DMSO-d.sub.6 and HPLC under isocratic conditions. The continuous phase used in the HPLC was an acetonitrile/water mixture (70% by weight/30% by weight). The stationary phase used was an RP-18 column.

(2) The x-ray diffractograms have been measured by means of Cu K alpha radiation (0.154 nm) at a temperature of 20 C. on a PANalytical XPert Pro MPD PW 3040/00 with an XCelerator detector.

(3) Preparation of N,N-bis-(2,2,6,6-tetramethylpiperidin-4-yl)isophthalamide in the phase (m.p.: 272 C.):

Example 1

Process Variant a

(4) In a horizontal forced mixer that works at a Froude number of 2.16 and has been equipped with plowshares, a distillation column and a protective gas connection, 2.5 mol of dimethyl isophthalate (m.p. 64-66 C.) and 5 mol of 4-amino-2,2,6,6-tetramethylpiperidine (in liquid form at room temperature) are homogenized with one another at a temperature of 60 C. under nitrogen until a monophasic liquid mixture forms. After the addition of 59.4 g of a sodium methoxide solution (25% by weight in methanol), the reaction mixture is mixed at 110 C. for a duration of 90 minutes. The alcohol from the catalyst formulation and the alcohol formed during the reaction are removed by distillation from the forced mixer. After the solid had been discharged and dried to constant weight, 1088.4 g (mass yield: 98.5%) of a white powder were isolated.

(5) The bulk density of the product was about 0.53 g/cm.sup.3.

(6) HPLC analysis of the white solid gave the following composition:

(7) TABLE-US-00001 Substance mol % Product 99.7 Monoamide 0.1 4-Amino-2,2,6,6-tetramethylpiperidine 0.1 Dimethyl isophthalate 0.1

(8) In the x-ray diffractogram, the following signals were identified for the product:

(9) TABLE-US-00002 2 theta d/angstrm Absolute intensity Relative intensity/% 4.99 17.69 10429.00 42.28 7.12 12.42 8059.00 32.67 10.11 8.75 3057.00 12.39 11.27 7.85 11217.00 45.47 12.19 7.26 4110.00 16.66 14.97 5.92 24667.00 100.00 16.00 5.54 5368.00 21.76 16.83 5.27 3289.00 13.33 17.76 4.99 6477.00 26.26 18.22 4.87 7616.00 30.88 18.88 4.70 9158.00 37.13 19.68 4.51 7802.00 31.63 20.82 4.27 11672.00 47.32 21.57 4.12 11646.00 47.21 22.67 3.92 17291.00 70.10 23.56 3.78 9127.00 37.00 24.78 3.59 5763.00 23.36 25.60 3.48 4740.00 19.22 26.70 3.34 5518.00 22.37 27.21 3.28 5428.00 22.01 28.52 3.13 4108.00 16.65 29.29 3.05 4554.00 18.46 30.48 2.93 5588.00 22.65 32.45 2.76 3628.00 14.71 33.45 2.68 4144.00 16.80 34.08 2.63 4649.00 18.85 36.22 2.48 4644.00 18.83 37.33 2.41 4463.00 18.09 38.37 2.35 4433.00 17.97 40.61 2.22 5763.00 23.36 41.32 2.18 6110.00 24.77 44.33 2.04 6077.00 24.64 46.49 1.95 5742.00 23.28

Example 2

Process Variant a

(10) In a horizontal forced mixer that works at a Froude number of 2.16 and has been equipped with plowshares, a distillation column and a protective gas connection, 2.5 mol of dibutyl isophthalate (in liquid form at room temperature) and 5 mol of 4-amino-2,2,6,6-tetramethylpiperidine (in liquid form at room temperature) are homogenized with one another at a temperature of 60 C. under nitrogen. After the addition of 59.4 g of a sodium methoxide solution (25% by weight in methanol), the reaction mixture is mixed at 130 C. for a duration of 180 minutes. In addition, a reduced pressure of 50 mbar is applied. The alcohol from the catalyst formulation and the alcohol formed during the reaction are removed by distillation from the forced mixer. After the solid had been discharged and dried to constant weight, 1075.6 g (mass yield: 97.3%) of a white powder were isolated.

(11) The bulk density of the product was about 0.53 g/cm.sup.3.

(12) HPLC analysis of the white solid gave the following composition:

(13) TABLE-US-00003 Substance mol % Product 99.7 Monoamide 0.1 4-Amino-2,2,6,6-tetramethylpiperidine 0.1 Dimethyl isophthalate 0.1

(14) In the x-ray diffractogram, the same characteristic signals as reported in example 1 were observed for the product.

Example 3

Process Variant b

(15) In a multineck flask with reflux condenser, precision glass stirrer, N.sub.2 inlet and internal thermometer, at a temperature of 30 C., 1 mol of dimethyl isophthalate is dissolved in 8.6 mol of 4-amino-2,2,6,6-tetramethylpiperidine. Subsequently, the reaction mixture is heated to a temperature of 50 C., and 23.76 g of sodium methoxide, dissolved in methanol (25% by weight), are added. After the addition of the catalyst, the reaction mixture is heated to a temperature of 90 C. for 4 hours. The polymer additive of the formula (I) precipitates out of the reaction mixture during this time and, after 4 hours have elapsed, is filtered off with suction at room temperature. After drying to constant weight, it was possible to isolate 415 g of a white solid (94% yield).

(16) HPLC analysis of the white solid gave the following composition:

(17) TABLE-US-00004 Substance mol % Product >99.7 Monoamide <0.1 4-Amino-2,2,6,6-tetramethylpiperidine <0.1 Dimethyl isophthalate <0.1

(18) In the x-ray diffractogram, the same characteristic signals as reported in example 1 were observed for the product. The bulk density of the product was 0.54 g/cm.sup.3.

Example 4

Process Variant c

(19) In a 4 L multineck flask with reflux condenser, precision glass stirrer, N.sub.2 inlet and internal thermometer, at a temperature of 40 C., 1 mol of dimethyl isophthalate and 2 mol of 4-amino-2,2,6,6-tetramethylpiperidine are dissolved in 1700 g of n-heptane. Subsequently, the reaction mixture is heated to a temperature of 50 C., and 23.76 g of sodium methoxide, dissolved in methanol (25% by weight), are added. After the addition of the catalyst, the reaction mixture is heated to a temperature of 90 C. for 6 hours. The polymer additive of the formula (I) precipitates out of the reaction mixture during this time and, after 6 hours have elapsed, is filtered off with suction at room temperature. After drying to constant weight, it was possible to isolate 424 g of a white solid (96% yield).

(20) HPLC analysis of the white solid gave the following composition:

(21) TABLE-US-00005 Substance mol % Product >99.5 Monoamide 0.2 4-Amino-2,2,6,6-tetramethylpiperidine 0.2 Dimethyl isophthalate <0.1

(22) In the x-ray diffractogram, the same characteristic signals as reported in example 1 were observed for the product. The bulk density of the product was 0.57 g/cm.sup.3.

Example 5

Comparative Example

(23) Preparation of N,N-bis(2,2,6,6-tetramethylpiperidin-4-yl)isophthalamide in the phase according to DE 60315329 T2 (m.p.: 272 C.):

(24) A reaction flask is charged with 0.95 mol (150.5 g) of 4-amino-2,2,6,6-tetramethylpiperidine and 1.07 mol (85.2 g) of 50% by weight aqueous NaOH solution in 470 g of isopropanol and 260 g of demineralized water. While stirring, 0.5 mol (102.1 g) of isophthaloyl chloride is added. Subsequently, the reaction mixture is heated to a temperature of 100 C., and the solids go completely into solution. 2 liquid phases are formed, of which the organic phase is removed and admixed with water, and the alcohol is distilled off. After cooling, the product is filtered off, washed with water and dried to constant weight. The yield of the reaction product is 200.0 g (95% of the theoretical value).

(25) The bulk density of the product is about 0.20 g/cm.sup.3.

(26) In the x-ray diffractogram, the following signals were identified:

(27) TABLE-US-00006 2 theta d/angstrm Absolute intensity Relative intensity/% 5.66 15.62 31473.00 100.00 9.33 9.48 7325.00 23.27 10.54 8.40 3475.00 11.04 11.28 7.84 7997.00 25.41 12.87 6.88 5399.00 17.15 14.14 6.26 5640.00 17.92 14.89 5.95 25649.00 81.50 15.16 5.84 28327.00 90.00 16.50 5.37 7164.00 22.76 16.91 5.24 13596.00 43.20 17.78 4.99 16524.00 52.50 19.67 4.51 10433.00 33.15 20.19 4.40 12160.00 38.64 21.79 4.08 11911.00 37.85 22.66 3.92 21629.00 68.72 23.68 3.76 17097.00 54.32 24.87 3.58 7694.00 24.45 26.77 3.33 10583.00 33.63 28.45 3.14 6061.00 19.26 30.72 2.91 6330.00 20.11 31.45 2.84 4019.00 12.77 32.02 2.79 3494.00 11.10 32.98 2.72 6001.00 19.07 34.03 2.63 5111.00 16.24 35.90 2.50 4840.00 15.38 37.62 2.39 4396.00 13.97 39.48 2.28 6330.00 20.11 40.61 2.22 6176.00 19.62 41.05 2.20 6250.00 19.86 43.13 2.10 9371.00 29.77 45.28 2.00 5454.00 17.33 47.17 1.93 5973.00 18.98 48.14 1.89 5824.00 18.50 58.99 1.57 4621.00 14.68