Cross-linkable monomers and polymers and the use thereof

Abstract

The invention relates to novel cross-linkable monomers that may be polymerized with ethylenically unsaturated comonomers to form cross-linkable copolymers. Said copolymers may particularly be used in the form of aqueous dispersions as formaldehyde-free adhesives or as coatings with good water resistance. The cross-linkable monomer is a compound in acid or salt form comprising an anion of the formula (I) and one or more cations for producing electrical neutrality, where R.sup.1 and R.sup.2 represent, independently of one another, hydrogen alkyl, cycloalkyl, aryl, aralkyl, COOR.sup.5, COO.sup. cat.sup.+ or CON(R.sup.6R.sup.7), R.sup.6 and R.sup.7 represent, independently of one another, hydrogen, alkyl, or aryl, cat.sup.4 represents a monovalent cation, and one of the groups R.sup.1 or R.sup.2 may also represent a group XR.sup.4CR.sup.5(OH)(SO.sub.3), wherein X, R.sup.4, and R.sup.5 assume one of the meanings listed below, R.sup.3 represents hydrogen, alkyl, or aryl, X is selected from the group of direct CC bond, O, CH.sub.2O, CH.sub.2NR.sup.8, COO or CONR.sup.8, R.sup.8 represents hydrogen, alkyl, or aryl, R.sup.4 represents alkylene, polyoxyalkylene, cycloalkylene, or arylene, and R.sup.5 represents hydrogen, alkyl, cycloalkyl, or aryl.

Claims

1. A copolymer comprising at least one monomer derived from a compound in acid or salt form and at least one further monomer which can undergo free radical copolymerization therewith, wherein the at least one monomer derived from a compound in acid or salt form contains an anion of the formula (I) and one or more cations for producing electroneutrality: ##STR00009## in which: R.sup.1 and R.sup.2, independently of one another, are hydrogen, alkyl, cycloalkyl, aryl, aralkyl, COOR.sup.5, COO.sup. Cat.sup.+, CON(R.sup.6R.sup.7), or XR.sup.4CR.sup.5(OH)(SO.sub.3.sup.); R.sup.4 is alkylene, polyoxyalkylene, or cycloalkylene; R.sup.5 is hydrogen, alkyl, cycloalkyl or aryl; R.sup.3, R.sup.6 and R.sup.7, independently of one another, are hydrogen, alkyl or aryl; Cat.sup.+ is a monovalent cation; X is selected from the group consisting of O, CH.sub.2NR.sup.8, COO or CONR.sup.8; and R.sup.8 is hydrogen, alkyl or aryl, wherein the at least one further monomer comprises an ethylene, a propylene, a styrene, an acrylate, a methacrylate, a vinyl ester of a saturated carboxylic acid, a butadiene or from mixtures of two or more of these monomers and wherein the at least one monomer of formula (I) is present in an amount of up to 10% by weight, based on the total weight of the monomers.

2. The copolymer as defined in claim 1, wherein the further monomer capable of free radical polymerization is selected from the group consisting of alpha-olefins, aliphatic hydrocarbons having two or more conjugated double bonds, vinyl esters of saturated carboxylic acids, esters of ethylenically unsaturated mono-or dicarboxylic acid, alkenyl-aromatics, and combinations thereof.

3. The copolymer as defined in claim 1, wherein the at least one monomer of formula (I)is present in an amount of from 0.01 to 5% by weight, based on the total weight of the monomers.

4. The copolymer as defined in claim 1, wherein R.sup.1 and R.sup.2, independently of one another, are hydrogen, alkyl, COOR.sup.5 or COO.sup. Cat.sup.+ and wherein R.sup.3 is hydrogen or alkyl.

5. The copolymer as defined in claim 4, wherein one of the radicals R.sup.1 or R.sup.2 is COOR.sup.5 or COO.sup. Cat.sup.+.

6. The copolymer as defined in claim 4, wherein R.sup.1 and R.sup.2 , independently of one another, are hydrogen, methyl, COOR.sup.5a or COO.sup. Cat+ and wherein at least and one of the radicals R.sup.1 or R.sup.2 is COOR.sup.5a or COO.sup. Cat+, R.sup.5a being hydrogen or C.sub.1-C.sub.6-alkyl, and wherein R.sup.3 is hydrogen or methyl.

7. The copolymer as defined in claim 1, wherein one of the radicals R.sup.1 or R.sup.2 is an XR.sup.4CR.sup.5 (OH)(SO.sub.3.sup.) group.

8. The copolymer as defined in claim 1, wherein X is selected from the group consisting of O, CONR.sup.8, or COO.

9. The copolymer as defined in claim 1, wherein R.sup.4 is alkylene.

10. The copolymer as defined in claim 9, wherein R.sup.4 is an unsubstituted C.sub.1-C.sub.6-alkylene.

11. The copolymer as defined in claim 1, wherein R.sup.5 is hydrogen or alkyl.

12. The copolymer as defined in claim 1, wherein the anion of formula (I) is an anion of the formula (IVa) or (IVb) ##STR00010##

13. A composition containing the copolymer as defined in claim 1, wherein the composition is in the form of an aqueous dispersion.

14. The composition as defined in claim 13, wherein the copolymer is a polyvinyl ester which contains at least 50% by weight of vinyl acetate monomer units and structural units derived from compounds of the formula (I).

15. The composition as defined in claim 13, wherein the composition comprises at least one protective colloid.

16. The composition as defined in claim 13, wherein the composition comprises at least one external crosslinking agent.

17. The composition as defined in claim 13, wherein the composition comprises at least one polyaldehyde or polyhydrazine.

18. The composition as defined in claim 13, wherein the composition contains Lewis acids in the form of acidic salts of complexable metal ions selected from the group consisting of aluminum chloride, aluminum nitrate, zirconium oxychloride, titanium sulfate, acidic salts with polyvalent complexable cations, and combinations thereof.

19. The composition as defined in claim 13, wherein the composition has a pH of from 2.5 to 4.5.

20. A cured composition produced by applying and drying the composition as defined in claim 13.

21. A redispersible dispersion powder formed from the composition as defined in claim 13.

22. A copolymer comprising at least one monomer derived from a compound in acid or salt form and at least one further monomer which can undergo free radical copolymerization therewith, wherein the at least one monomer derived from a compound in acid or salt form contains an anion of the formula (I) and one or more cations for producing electroneutrality: ##STR00011## in which: R.sup.1 and R.sup.2, independently of one another, are hydrogen, alkyl, cycloalkyl, aryl, aralkyl, COOR.sup.5, COO.sup. Cat.sup.+, CON(R.sup.6R.sup.7), or XR.sup.4CR.sup.5 (OH)(SO.sub.3.sup.); R.sup.4 is alkylene, polyoxyalkylene, cycloalkylene or arylene; R.sup.5 is hydrogen, alkyl, cycloalkyl or aryl; R.sup.3, R.sup.6 and R.sup.7, independently of one another, are hydrogen, alkyl or aryl; Cat.sup.+ is a monovalent cation; X is selected from the group consisting of O, CH.sub.2NR.sup.8, COO or CONR.sup.8; and R.sup.8 is hydrogen, alkyl or aryl, wherein the at least one further monomer comprises an ethylene, a propylene, a styrene, an acrylate, a methacrylate, a vinyl ester of a saturated carboxylic acid, a butadiene or from mixtures of two or more of these monomers and wherein the at least one monomer of formula (I) is present in an amount of up to 10% by weight, based on the total weight of the monomers.

Description

EXAMPLE 1A

Preparation of 2-formylethyl Acrylate on the Basis of JP-A-60/72,954

(1) 159.6 g (2.85 mol) of acrolein (quality >95%, Fluka) were initially introduced together with 100 mg of hydroquinone in a cylindrical glass reactor having a capacity of 3000 ml and provided with a stirrer and metering apparatuses. Thereafter, 1024 g (14.2 mol) of acrylic acid (BASF AG) and then 66.6 g of Amberlyst A 21 (basic ion exchanger from Rohm & Haas) were added with stirring. The mixture was heated to an internal temperature of 50 C. in a water bath, stirred at this temperature for 10 hours and then cooled to room temperature. For isolating the crude product, the cooled reaction mixture was filtered over a fluted filter and the filtrate was evaporated in a rotary evaporator under a water jet vacuum at a bath temperature of 72 C. until no more distillate passed over. The residue of evaporation was taken up in 400 ml of dichloromethane and stirred rapidly 8 times with 400 ml of 5% strength sodium bicarbonate solution each time in a beaker and then shaken with 2 times 400 ml of deionized water. The organic phase was dried over 20 g of magnesium sulfate and the methylene chloride was then evaporated off in a rotary evaporator. The residue (35.8 g) was distilled in vacuo. The main fraction was obtained at the boiling range of 79-81 C. (P<2 mm Hg). Yield: 12 g (3.3%, based on acrolein used).

(2) The IR spectrum of the compound was identical to the spectrum published in JP-A-60/72,954, on page 4.

EXAMPLE 1B

Preparation of the Bisulfite Adduct of 2-formylethyl Acrylate (FEA-BSA)

(3) 12 g (0.094 mol) of 2-formylethyl acrylate were initially introduced into a 100 ml conical flask blanketed with nitrogen, and 0.076 g (0.5 mmol) of 1-phenyl-3-pyrazolidinone (as a stabilizer) was added. Thereafter, a solution of 5.34 g (0.028 mol) of sodium metabisulfite in 117 ml of deionized water were added dropwise to the reaction mixture with thorough mixing and cooling with water (about 20 C.) over 15 minutes. After the end of the addition, stirring was effected for a further 10 minutes. Thereafter, the reaction mixture was extracted with 2 about 30 ml of ethyl acetate for recovering unconverted 2-formylethyl acrylate (see below). For precipitating the adduct, 12 ml of ethanol were first added to the aqueous phase in an ice bath and stirring was effected until the product was precipitated. Thereafter, about 30 ml of ethyl acetate cooled in an ice bath were added to the reaction mixture and the finely crystalline precipitate was suspended. The product was filtered over a suction filter, washed with the remaining ethyl acetate and dried in a vacuum drying oven. 5.2 g (22.5%), based on aldehyde used, were obtained.

(4) .sup.1H-NMR (D.sub.2O; RT; ppm: 6.45 H.sub.cisH.sub.transCCH (dd, J=17.4 1.1 Hz, 1H), 6.22 H.sub.cisH.sub.transCCH (dd, J=17.4, 10.6 Hz, 1H), 6.00 H.sub.cisH.sub.transCCH (dd, J=10.6, 1.1 Hz, 1H), 4.56 HOC(H)SO.sub.3Na (m, 1H), 4.38 OCH.sub.2 (m, 2H), 2.38, 2.05 CH.sub.A/BC(H)(OH)SO.sub.3.sup. (m, 1H; m 1H).

(5) .sup.13H-NMR (D.sub.2O; RT; ppm): 171.1 C(O)O, 135.3 H.sub.2C, 130.2 CH, 83.5 C(H)(OH)SO.sub.3.sup., 64.2 OCH.sub.2, 32.9 CH.sub.2C(H)(OH)SO.sub.3.sup.

(6) IR (KBr, cm.sup.1): 3416 br. s, 2964 w, 1726 s, 1636 m, 1619 w, 1412 m, 1299 m, 1199 s, 1123 m, 1044 s, 987 m, 812 m, 635 m, 585 m, 536 m, 436 w.

EXAMPLE 2A

Preparation of 3-formylpropyl Acrylate by Oxidation of Butanediol Monoacrylate

(7) The reaction described below was carried out on the basis of P. L. Anelli, F. Montanari, S. Quici; Organic Syntheses, Coll. Vol. 8, 367 (1993); Vol. 60, 212 (1990).

(8) 96.1 g (0.667 mol) of butanediol monoacrylate (commercial product of BASF AG) and 1.17 g (7.51 mmol) of TEMPO (2,2,6,6-tetramethylpiperidin-N-oxyl) were weighed into a 2 l three-necked round-bottomed flask with magnetic stirrer and internal thermometer and dissolved in 340 g of methylene chloride. A solution of 8.94 g (75.1 mmol) of KBr in 37.5 ml of deionized water was added thereto and cooled to 0-10 C. by means of a suitable, effective cooling apparatus with thorough mixing. In a separate vessel, 614 g (about 0.825 mol) of an aqueous approx. 10% strength sodium hypochlorite solution were diluted with 200 ml of deionized water and adjusted to pH 9 with 25.5 g (0.304 mol) of sodium bicarbonate (the pH should be checked using a suitable measuring apparatus; required amount of sodium bicarbonate may differ depending on the sodium hypochlorite solution used) and then added dropwise to the reaction mixture via a dropping funnel in the course of 15-20 minutes. The temperature was kept as far as possible (cooling) just above 0 C. and was not to exceed 15 C. After addition was complete, stirring was effected for a further 3 minutes. After the end of the reaction, the organic phase and the aqueous phase were separated from one another as rapidly as possible and the aqueous phase was extracted with 260 g of methylene chloride. The combined organic phases were then washed in succession with a solution of 2.40 g (14.5 mmol) of potassium iodide in 150 ml of 10% strength aqueous hydrochloric acid, a solution of 9.9 g (62.6 mmol) of sodium thiosulfate in 90 ml of water, 2150 ml of a 10% strength sodium bicarbonate solution in deionized water and finally with 150 ml of deionized water. The organic phase was dried over anhydrous magnesium sulfate and the solvent was then removed in a rotary evaporator. 89 g of crude product were obtained. About 6 mol % of butanediol monoacrylate and about 1 mol % of a hemiacetal of 3-formylpropyl acrylate and butanediol monoacrylate were still present as main impurities in the crude product. The crude product can, however, be used without further purification for the preparation of the bisulfite adduct.

(9) .sup.1H-NMR (CDCl.sub.3; RT; ppm): 9.80 CHO (t, J=1.2 Hz, 1H), 6.39 H.sub.cisH.sub.transCCH (dd, J=17.5, 1.5 Hz, 1H), 6.11 H.sub.cisH.sub.transCCH (dd, J=17.5, 10.5 Hz, 1H), 5.84 H.sub.cisH.sub.transCCH (dd, J=10.5, 1.5 Hz, 1H), 4.20 OCH.sub.2 (t, J=6.5 Hz, 2H), 2.57 CH.sub.2CHO (td, J=7.0, 1.2 Hz, 2H), 2.03 CH.sub.2CH.sub.2CH.sub.2 (tt, J=7.0, 6.5 Hz, 2H).

(10) .sup.13H-NMR (CDCl.sub.3; RT; ppm): 201.1 CHO; 166.0 C(O)O, 130.9 H.sub.2C, 128.3 CH, 63.5 OCH.sub.2, 40.5 CH.sub.2CHO, 21.4 CH.sub.2CH.sub.2CH.sub.2.

(11) IR (film on KBr, cm.sup.1): 3107 w, 3039 w, 2962 m, 2900 m, 2832 m, 2728 m, 1724 s, 1636 m, 1620 m, 1457 m, 1442 m, 1410 s, 1297 s, 1273 s, 1192 s, 1063 s, 986 s, 811 s, 667 w.

EXAMPLE 2B

Bisulfite Adduct of 3-formylpropyl Acrylate (FPA-BSA)

(12) 133 g (0.93 mol) of 3-formylpropyl acrylate were initially introduced into a 250 ml 2-necked flask blanketed with nitrogen, and 0.76 g (4.7 mmol) of 1-phenyl-3-pyrazolidinone (as a stabilizer) was added. Thereafter, a solution of 53.2 g (0.28 mol) of sodium metabisulfite in 117 ml of deionized water was added dropwise to the reaction mixture with thorough mixing and cooling with water (about 20 C.) over 15 minutes. After the end of the addition, stirring was effected for a further 10 minutes. Thereafter, the reaction mixture was extracted with 2 approx. 100 ml of ethyl acetate for recovering unconverted 3-formylpropyl acrylate (see below). Thereafter, 100 ml of ethanol were added to the aqueous phase in an ice bath and stirred until the product crystallized. Thereafter, about 500 ml of precooled ethyl acetate were added to the crystal slurry likewise in the ice bath and a suspension was produced and then filtered. The filtercake comprising 3-formylpropyl acrylate was washed with 2300 ml of ethyl acetate and dried. 82 g (36%, based on aldehyde; 60%, based on sodium metabisulfite) were obtained.

(13) For recovering unconverted 3-formylpropyl acrylate, the ethyl acetate phase was dried over anhydrous magnesium sulfate and the methylene chloride was removed in vacuo. The recycled material still contained unknown impurities but could be used without problems as a 50/50 mixture with fresh aldehyde for the preparation of the bisulfite adduct of 3-formylpropyl acrylate.

(14) .sup.1H-NMR (d6-DMSO; RT; ppm): 6.32 H.sub.cisH.sub.transCCH (dd, J=17.3, 1.6 Hz, 1H), 6.17 H.sub.cisH.sub.transCCH (dd, J=17.3, 10.3 Hz, 1H), 5.93 H.sub.cisH.sub.transCCH (dd, J=10.3, 1.6 Hz, 1H), 5.23 HOC(H)SO.sub.3.sup. (d, J=5.7 Hz, 1H), 4.10 OCH.sub.2 (m, 2H), 3.82 HOC(H)SO.sub.3Na (M, 1h), 1.80 CH.sub.2CH.sub.2CH.sub.2 (m, 2H), 1.65, 1.52 CH.sub.A/BC(H)(OH)SO.sub.3.sup. (m, 1H; m 1H).

(15) .sup.13H-NMR (d6-DMSO; RT; ppm): 169.3 C(O)O, 131.3 H.sub.2C, 128.3 CH, 82.3 C(H)(OH)SO.sub.3.sup., 64.1 OCH.sub.2, 28.0/24.8 CH.sub.2CH.sub.2C(H)(OH)SO.sub.3.sup.

(16) IR (KBr, cm.sup.1): 3352 br. s, 3040 w, 2960 m, 2902 w, 1729 s, 1634 m, 1620 w, 1467 m, 1409 s, 1390 m, 1362 m, 1296 s, 1272 s, 1246 s, 1230 s, 1212 s, 1189 s, 1168 s, 1151 s, 1122 m, 1098 m, 1046 s, 986 s, 885 w, 809 m, 765 w, 675 m, 632 s.

(17) Polymerizations with the Bisulfite Adducts FEA-BSA and FPA-BSA

(18) All stated amounts in parts are understood as meaning mass of the respective substance, based on the mass of the vinyl acetate used.

(19) General method: A solution of 10 parts of partly hydrolyzed polyvinyl alcohol having a degree of hydrolysis of 88 mol % and a viscosity of the 4% strength by weight solution at 20 C. of 18 mPa.Math.s in 88 parts by weight of deionized water was prepared in a stirred glass tank reactor provided with anchor stirrer, feed facilities, reflux condenser, and jacketed against cooling. After addition of 0.09 part of Agitan 280 antifoam (Mnzing-Chemie) and 0.1 part of sodium acetate, 8.8 parts of altogether 100 parts of vinyl acetate were incorporated by emulsification. The internal temperature was increased to 60 C. and the polymerization was initiated by addition of a solution of 0.02 part of ammonium persulfate in 0.66 part of deionized water.

(20) After the reaction had started, 91.2 parts of vinyl acetate, a solution of 0.03 part of ammonium persulfate in 2.5 parts of deionized water and a solution of the functional comonomers mentioned in table 1 in 2.5 parts of deionized water were metered uniformly into the polymerization batch in three separate feeds in the course of three hours. The jacket temperature was controlled so that the polymerization took place at a slowly increasing internal temperature from 68 C. at the beginning to about 80 C. at the end of the metering.

(21) After the end of the metering, a solution of 0.01 part of ammonium persulfate in 0.5 part of deionized water was added and postpolymerization was effected for initially one hour at 80 C.

(22) In the case of examples 3 and C1, postpolymerization was effected with solutions of 0.04 part of Trigonox AW 70 (from Akzo, tert-butyl hydroperoxide) in 0.15 part of water and 0.07 part of ascorbic acid in 0.5 part of water at 80 C. and 75 C., respectively, for demonomerization. In examples 4-7, the demonomerization was effected with solutions of 0.08 part of sodium metabisulfite in 0.5 part of deionized water and 0.05 part of ammonium persulfate in 0.5 part of deionized water at 80 C./75 C. In these examples, in each case solutions of 0.2 part of sodium metabisulfite in 2 parts of deionized water were additionally stirred in for stabilization at room temperature. Dispersions having solids contents of from 51 to 53% were thus obtained. The viscosities of the products obtained are shown in table 2.

(23) For testing as a wood adhesive, the products were modified with in each case 2 parts of butyldiglycol acetate, 0.025 part of Agitan 305 antifoam (Mnzing-Chemie) and 5 parts of weight of a 28% strength aqueous aluminium chloride solution.

(24) The testing of the formulated dispersions was effected on beech wood test specimens according to the test standard DIN EN 204/D3. In this test, the resistance of the adhesive film to exposure to cold water for four days is tested. Without use of crosslinking monomers, the adhesive film would have no water resistance at all, i.e. the test specimens would disintegrate during the storage. In addition to the basic information about the suitability of the products for use in the chosen application, the test also simultaneously provides information about the crosslinking density in the film, since the values of the wet adhesive strength decrease with increasing film swelling and reemulsifiability, which are effectively reduced by crosslinking. This is also evident from the water absorptions of the pure films, which were determined by a customary method (see EP-A 1 458 774, page 8). The gluing and testing were carried out taking into account the following characteristic data:

(25) TABLE-US-00001 TABLE 1 Parameters of standard adhesive bond Glue application 150 20 g/m.sup.2 (application on both sides) Press time 2 hours Press pressure 0.7 N/mm.sup.2 Number of test specimens per 20 test sequence Testing according to storage 7 days under standard sequence in DIN EN 204 D3/3; climatic conditions immediate test 4 days in cold water Test temperature 23 2 C. Feed rate 50 mm/min Required tensile strength 2 N/mm.sup.2

(26) Table 2 shows the results of the polymerizations and the results of the testing of the performance characteristics. In the case of comparative example C1, a polymerization with the customary crosslinking monomer N-methylolacrylamide was carried out for comparison. For this purpose, a commercially available 48% strength product from S.N.F. Floerger was used. The amount stated in the table is based on the active substance. In examples 3 and 4, amounts of the bisulfite adduct monomers which are the molar equivalent of this amount were used in order to be able to make a direct comparison of the crosslinking efficiency. All formulations of the example dispersions according to the invention gave a non-reemulsifying film. The crosslinking effect observed is sufficient for safely complying with the chosen test standard. It can be seen that, in the case of equimolar replacement of N-methylolacrylamide by the novel monomers, the efficiency is comparable or, as in the case of FPA-BSA, is even better. Formaldehyde is neither introduced by the products nor forms during the crosslinking.

(27) TABLE-US-00002 TABLE 2 Data from the polymerization experiments and tests Wet adhesive Amount strength on used Water beech wood (based Viscosity absorption according to on 100 Brookfield of the EN 204 D3/3 Cross- parts of RVT, film [%] [N/mm.sup.2] linking vinyl 23 C. after after Example monomer acetate) [mPa .Math. s] formulation formulation 3 FEA-BSA 0.88 11 600 27 2.6 4 FPA-BSA 0.93 120 000 14 7.0 5 FPA-BSA 0.7 41 000 22 3.9 6 FPA-BSA 0.47 26 400 32 2.6 7 FPA-BSA 0.23 19 950 35 1.5 C1 NMA 0.38 28 750 2.3