CH-ACIDIC METHACRYLIC ESTERS FOR THE PREPARATION OF AQUEOUS POLYMER DISPERSIONS

Abstract

The present invention relates to CH-acidic methacrylic esters and also copolymers obtainable from CH-acidic methacrylic esters. Furthermore, the present invention relates to coating compositions comprising these copolymers.

Claims

1-11. (canceled)

12. A compound of formula (I): ##STR00003## wherein R.sup.1 is selected from a hydrogen atom and a methyl group; and R.sup.2 is an optionally substituted alkylene group of formula C.sub.nH.sub.m, wherein n=2 to 4 and m=2 to 8.

13. The compound of claim 12, wherein the alkylene group R.sup.2 is selected from the group consisting of: 1,2-ethylene; 1,3-propylene; 1,2-propylene; 1,4-butylene; 1,3-(2-hydroxy)propylene; and 1,3-(2,2-dimethyl)propylene.

14. The compound of claim 12, wherein R.sup.1 is a methyl group.

15. The compound of claim 13, wherein R.sup.1 is a methyl group.

16. A copolymer obtainable by polymerization of a monomer mixture comprising a compound of formula (I): ##STR00004## wherein R.sup.1 is selected from a hydrogen atom and a methyl group; and R.sup.2 is an optionally substituted alkylene group of formula C.sub.nH.sub.m, wherein n=2 to 4 and m=2 to 8; and wherein the monomer mixture comprises at least 0.5 wt % of the compound of formula I based on the weight of the monomer mixture.

17. The copolymer of claim 16, wherein the alkylene group R.sup.2 of said compound of formula I is selected from the group consisting of: 1,2-ethylene; 1,3-propylene; 1,2-propylene; 1,4-butylene; 1,3-(2-hydroxy)propylene; and 1,3-(2,2-dimethyl)propylene.

18. The copolymer of claim 16, wherein R.sup.1 of said compound of formula I is a methyl group.

19. The copolymer of claim 17, wherein R.sup.1 of said compound of formula I is a methyl group.

20. The copolymer of claim 16 wherein said monomer mixture comprises at least 1 wt %, of said compound of formula I based on the weight of the monomer mixture.

21. The copolymer of claim 16, wherein the monomer mixture comprises: 0.5 to 90 wt % of said compound of formula I; 10 to 95 wt % of at least one monomer comprising ester groups; 0 to 10 wt % of at least one monomer with an acid group; and 0 to 50 wt % of at least one styrene monomer, based on the weight of the copolymer.

22. The copolymer of claim 21, wherein the alkylene group R.sup.2 of said compound of formula I is selected from the group consisting of: 1,2-ethylene; 1,3-propylene; 1,2-propylene; 1,4-butylene; 1,3-(2-hydroxy)propylene; and 1,3-(2,2-dimethyl)propylene.

23. The copolymer of claim 21, wherein R.sup.1 of said compound of formula I is a methyl group.

24. The copolymer of claim 22, wherein R.sup.1 of said compound of formula I is a methyl group.

25. A coating, obtainable by applying an aqueous dispersion to an article to be coated and subsequently drying and curing the article, wherein said aqueous dispersion comprises 0.1 to 90 wt % of a copolymer based on the weight of the aqueous dispersion; wherein said copolymer is obtainable by polymerization of a monomer mixture comprising a compound of general formula (I): ##STR00005## wherein R.sup.1 is selected from a hydrogen atom and a methyl group; and R.sup.2 is an optionally substituted alkylene group formula C.sub.nH.sub.m, wherein n=2 to 4 and m=2 to 8; and wherein the monomer mixture comprises at least 0.5 wt %, of the compound of formula I based on the weight of the monomer mixture.

26. The coating of claim 25, wherein the alkylene group R.sup.2 of the compound of formula I is selected from the group consisting of: 1,2-ethylene; 1,3-propylene; 1,2-propylene; 1,4-butylene; 1,3-(2-hydroxy)propylene; and 1,3-(2,2-dimethyl)propylene.

27. The coating of claim 25, wherein R.sup.1 of the compound of formula I is a methyl group.

28. The coating of claim 26, wherein R.sup.1 of said compound of formula I is a methyl group.

29. The coating of claim 25, wherein the monomer mixture comprises: 0.5 to 90 wt % of the compound of formula I; 10 to 95 wt % of at least one monomer comprising ester groups; 0 to 10 wt % of at least one monomer with an acid group; and 0 to 50 wt % of at least one styrene monomer, based on the weight of the copolymer.

30. The coating of claim 25, wherein the aqueous dispersion contains an aldehyde or a ketone which enters into a condensation reaction with the copolymer during the curing.

31. The coating of claim 25, wherein the aqueous dispersion contains an isocyanate which enters into addition reactions with the copolymer according to claim 4 or 5 during the curing.

Description

EXAMPLES

Analysis

[0137] Gas chromatography (GC)

[0138] Instrument: 7820A from Agilent Technologies

[0139] Column: DB5, 30 m, ø 0.250 mm, 0.25 μm film

Temperature Programme:

[0140] Injection at 60° C., then hold for 2 min. Subsequently heat to 240° C. at 20° C./min and after reaching that temperature, hold at 240° C. for 8 min.

Example 1: Preparation of N-(2-ethylamino)-2-cyanoacetamide

[0141] 600 g (10.0 mol) of ethylenediamine are initially charged in a 2 l four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 500 ml addition funnel. 248 g (2.5 mol) of methylcyanoacetate are metered in thereto dropwise within 60 minutes, such that the reaction temperature does not exceed 30° C. During this time, the four-necked round-bottomed flask is cooled in an ice-water bath. In the course of the addition of methylcyanoacetate, the reaction mixture becomes increasingly pink coloured, and then lilac. To complete the reaction, the reaction mixture is stirred for a further 90 minutes at room temperature.

[0142] Subsequently, the excess ethylenediamine is removed under reduced pressure. For this purpose, the reaction mixture is heated to 100° C. (oil bath temperature) and the volatile constituents are distilled off over a period of 2 hours at a pressure of up to 5 mbar.

[0143] The product is obtained as a dark, glass-like solid with a purity of 97.9 area % (determined using GC-RV). The product yield is 309 g (95%).

Comparative Example 1: Preparation of N,N′-ethylenebismethacrylamide

[0144] A 40% aqueous solution of ethylenediamine (25.5 g, 0.17 mol) is initially charged in a 250 ml four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 100 mi addition funnel. 26 g (0.17 mol) of methacrylic anhydride are metered in thereto dropwise within 60 minutes, such that the reaction temperature does not exceed 30° C. During this time, the four-necked round-bottomed flask is cooled in an ice-water bath. In the course of the addition of methacrylic anhydride, a white solid is formed.

[0145] The white solid is separated off by filtration, and dried. It is N,N′-ethylenebismethacrylamide with a purity of 74.8 area % (determined using GC-RV). The product yield is 20 g (60%).

Example 2: Preparation of N-(2-cyanoethylamidoethyl)methacrylamide

[0146] A mixture of 147 g (1.2 mol) of N-(2-ethylamino)-2-cyanoacetamide and 600 g (6.0 mol) of methylmethacrylate is initially charged in a 1 l four-necked round-bottomed flask with air inlet, sabre stirrer, stirrer motor, and a 50 cm-long 29 mm-thick mirrored column with random packing, filled with 6×6 Raschig rings. 7 mg (10 ppm) of 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl and 0.15 g (200 ppm) of hydroquinone monomethyl ether are added thereto, followed by 7.4 g of a mixture comprising 65.6 wt % of dioctyttin oxide and 34.4 wt % of tetraisopropyl titanate.

[0147] The reaction mixture is heated under reflux, with the methanol forming being distilled off as an azeotrope via the column with random packing. After approximately 3.5 hours, the conversion, determined by GC, is 58%.

Example 3: Preparation of N-(2-cyanoethylamidoethyl)methacrylamide

[0148] 312 g (2.4 mol) of N-(2-ethylamino)-2-cyanoacetamide from example 1 are dissolved in 488 g of water in a 21 three-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 500 ml addition funnel. 370 g (2.4 mol) of methacrylic anhydride are slowly added dropwise thereto, with a light brown precipitate being formed. The reaction mixture is then stirred for a further 1.5 hours at 80° C.

[0149] The resulting clear, dark red reaction mixture has low boilers removed therefrom under reduced pressure, is concentrated down to 646 g, and has 400 g of isopropanol added thereto. This leads to the formation of a precipitate which is separated off by filtration.

[0150] The product is obtained as a brown, crystalline solid with a purity of 95.0 area % (determined using GC-RV). The product yield is 346 g (73.9%).

[0151] The solubility of the product in water was determined as follows:

[0152] The product was stirred with water for three days at room temperature and the composition of the aqueous phase obtained in this way was determined using HPLC. The aqueous phase contained 6.7 wt % of the product.

[0153] A further sample of the product was stirred with water for three hours at 80° C. and cooled back to room temperature. The composition of the aqueous phase obtained in this way was subsequently determined using HPLC. The aqueous phase contained more than 10 wt % of the product.

[0154] The product has a high water-solubility. Therefore, it can be used in emulsion polymerization even in the absence of organic solvents.

Example 4: Preparation of N-(2-butylamino)-2-cyanoacetamide

[0155] 353 g (4.0 mol) of 1,4-diaminobutane are melted at approximately 30° C. in a 1 l four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 250 ml addition funnel. 99 g (1.0 mol) of methylcyanoacetate are metered in dropwise thereto within 30 minutes, such that the reaction temperature remains at approximately 30° C. to 40° C. During this time, the four-necked round-bottomed flask is cooled in an ice-water bath. In the course of the addition of methylcyanoacetate, the reaction mixture becomes increasingly intensely yellow coloured. To complete the reaction, the reaction mixture is stirred for a further 90 minutes at room temperature, with the reaction mixture becoming red coloured.

[0156] Subsequently, excess 1,4-diaminobutane is removed under reduced pressure. For this purpose, the reaction mixture is heated to 100° C. (oil bath temperature) and the volatile constituents are distilled off over a period of 2.5 hours at a pressure of up to 2 mbar.

[0157] The product is obtained as a dark, glass-like solid with a purity of 89.1 area % (determined using GC-RV). The product yield is 146 g (84%).

Example 5: Preparation of N-(2-cyanoethylamidobutyl)methacrylamide

[0158] 360 g (0.93 mol) of N-(2-butylamino)-2-cyanoacetamide from example 3 are dissolved in 540 g of water in a 1 l four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 500 ml addition funnel and cooled to 0° C. in an ice-water bath. 143 g (0.93 mol) of methacrylic anhydride, dissolved in 300 ml of methanol, are slowly added thereto dropwise. Subsequently, the reaction mixture is stirred overnight at room temperature, with the reaction mixture becoming green coloured.

[0159] The reaction mixture is concentrated under reduced pressure at 80° C. and 35 mbar to 263 g. The residue is dissolved in 160 g of isopropanol and the resulting solution is stored at room temperature. This leads to the formation of a precipitate which is separated off by filtration.

[0160] The product is obtained as a yellow crystalline solid. The purity is approximately 94.0 area % (determined using GC-RV).

[0161] The solubility of the product in water was determined as follows:

[0162] The product was stirred with water for two days at room temperature and the composition of the aqueous phase obtained in this way was determined using HPLC. The aqueous phase contained 6.2 wt % of the product.

[0163] A further sample of the product was stirred with water for one hour at 60° C. and cooled back to room temperature. The composition of the aqueous phase obtained in this way was subsequently determined using HPLC. The aqueous phase contained 8.1 wt % of the product.

[0164] The product has a high water-solubility. Therefore, it can be used in emulsion polymerization even in the absence of organic solvents.

Comparative Example 2: Preparation of N-(2-hexylamino)-2-cyanoacetamide

[0165] 465 g (4.0 mol) of 1,6-diaminohexane are melted at approximately 41° C. in a 1 l four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 250 ml addition funnel. 99 g (1.0 mol) of methylcyanoacetate are metered in dropwise thereto within 30 minutes, such that the reaction temperature remains at approximately 50° C. to 75° C. In the course of the addition of methylcyanoacetate, the reaction mixture becomes increasingly intensely yellow coloured. To complete the reaction, the reaction mixture is stirred for a further 90 minutes at approximately 50° C. to 75° C., with the reaction mixture becoming red coloured.

[0166] Subsequently, the excess 1,6-diaminohexane is removed under reduced pressure. For this purpose, the reaction mixture is heated to 120° C. (oil bath temperature) and the volatile constituents are distilled off over a period of 4 hours at a pressure of up to 2 mbar.

[0167] The product is obtained as a dark, glass-like solid with a purity of approximately 100 area % (determined using GC-RV). The product yield is 172 g (94%).

Comparative Example 3: Preparation of N-(2-cyanoethylamidohexyl)methacrylamide

[0168] 31 g (0.2 mol) of methacrylic anhydride and 150 g of water are initially charged in a 1 l four-necked round-bottomed flask with sabre stirrer, stirrer motor, thermometer and a 500 ml addition funnel and cooled to 0° C. in an ice-water bath.

[0169] 360 g (0.93 mol) of N-(2-hexylamino)-2-cyanoacetamide from comparative example 2 are dissolved in 3240 g of methanol at 60° C. and cooled to room temperature. This solution is added over a period of 30 minutes via the addition funnel to methacrylic anhydride. The reaction temperature is kept below 20° C. The reaction mixture is then stirred for a further 3 hours at room temperature.

[0170] The product formed is detected in the reaction mixture using GC-RV and can be isolated by crystallization from isopropanol.

[0171] The solubility of the product in water was determined as follows:

[0172] The product was stirred with water for three days at room temperature and the composition of the aqueous phase obtained in this way was determined using HPLC. The product is virtually insoluble in water.

[0173] A further sample of the product was stirred with water for three hours at 80° C. and cooled to room temperature. The composition of the aqueous phase obtained in this way was subsequently determined using HPLC. The product is virtually insoluble in water; only impurities from the product are dissolved and detected.

[0174] The product has a very low water-solubility. Therefore, it cannot be used in emulsion polymerization in the absence of organic solvents.