POLYMER, PROCESS AND USE

Abstract

The current invention relates to a process for preparing an aqueous binder composition free of organic solvent, the process comprising at least the following steps: A) preparing a hydrophilic vinyl polymer (Polymer A) by polymerisation of a monomer composition A that contains: Ai) at least one carboxylic acid functional olefinically unsaturated monomer; and Aii) at least one olefinically unsaturated monomer different than Ai); and Aiii) optionally at least one wet adhesion promoting olefinically unsaturated monomer different than Ai and Aii); where Polymer A has an acid value (AV) from 32 to 98 mg KOH/g of solid Polymer A; B) preparing a hydrophobic vinyl polymer (Polymer B) by emulsion polymerization of a monomer composition B in the presence of Polymer A where the monomer composition B contains: Bi) at least one olefinically unsaturated monomer; Bii) optionally carboxylic acid functional olefinically unsaturated monomer different than Bi); and Biii) optionally wet adhesion promoting olefinically unsaturated monomer different than Bi); where Polymer B has an acid value (AV) of no more than 23.4 mg KOH/g of solid polymer B, wherein at least a part of the carboxylic acid groups that are present in Polymer A and Polymer B are neutralized during or following the steps A and/or B to form a (partially) neutralized polymer emulsion; where the weight average molecular weight (Mw) of Polymer A is lower than the weight average molecular weight (Mw) of polymer B; and wherein the process is further characterized by the presence of a further step C) reacting at least 10 mol % of the carboxylic acid and/or carboxylate salt groups of the (partially) neutralized polymer emulsion with an iminating agent to produce an iminated polymer C; wherein the total amount of surfactant applied in steps A, B and C is at most 0.5 wt. %, based on the total weight of monomers charged for the preparation of polymer A and polymer B

Claims

1. A process for preparing an aqueous binder composition free of organic solvent, the process comprising at least the following steps: A) preparing a hydrophilic vinyl polymer (Polymer A) by polymerisation of a monomer composition A that contains: Ai) at least one carboxylic acid functional olefinically unsaturated monomer; and Aii) at least one olefinically unsaturated monomer different than Ai); and Aiii) optionally at least one wet adhesion promoting olefinically unsaturated monomer different than Ai and Aii); where Polymer A has an acid value (AV) from 32 to 98 mg KOH/g of solid Polymer A; B) preparing a hydrophobic vinyl polymer (Polymer B) by emulsion polymerization of a monomer composition B in the presence of Polymer A where the monomer composition B contains: Bi) at least one olefinically unsaturated monomer; Bii) optionally carboxylic acid functional olefinically unsaturated monomer different than Bi); and Biii) optionally wet adhesion promoting olefinically unsaturated monomer different than Bi); where Polymer B has an acid value (AV) of no more than 23.4 mg KOH/g of solid polymer B, wherein at least a part of the carboxylic acid groups that are present in Polymer A and Polymer B are neutralized during or following the steps A and/or B to form a (partially) neutralized polymer emulsion; where the weight average molecular weight (Mw) of Polymer A is lower than the weight average molecular weight (Mw) of polymer B; and wherein the process is further characterized by the presence of a further step C) reacting at least 10 mol % of the carboxylic acid and/or carboxylate salt groups of the (partially) neutralized polymer emulsion with an iminating agent to produce an iminated polymer C; wherein the total amount of surfactant applied in steps A, B and C is at most 0.5 wt. %, based on the total weight of monomers charged for the preparation of polymer A and polymer B.

2. Process according to claim 1, wherein the total amount of surfactant applied in steps A, B and C is at most 0.2 wt. %, based on the total weight of monomers charged for the preparation of Polymer A and Polymer B.

3. Process according to claim 1, wherein the total amount of surfactant is added at the start of step A and/or during step A.

4. Process according to claim 1, wherein from 10 mol % to 90 mol % of the total amount of carboxylic acid and carboxylate salt groups present in the (partially) neutralized polymer emulsion is reacted with an iminating agent to produce the iminated polymer C, preferably from 20 to 80 mol % of the total amount of the carboxylic acid and carboxylate salt groups present in the (partially) neutralized emulsion is reacted with an iminating agent to produce the iminated polymer C.

5. Process according to claim 1, wherein the iminating agent is propylene imine.

6. Process according to claim 1, where the percentage of carboxylic acid and carboxylate salt groups that is reacted with the iminating agent is determined such that the degree of iminization is between DI low and DI high which are determined by the following formulas:
DI.sup.LOW(%)=[(AV*0.682)−11.8]*100%,
DI.sup.HIGH(%)=[(AV*1.061)−14]*100%, where AV is the AV of the (partially) neutralized polymer emulsion.

7. Process according to claim 1, wherein the amount of monomer Ai) is from 5 to 15 wt. %, relative to the total weight of monomers charged for the preparation of polymer A.

8. Process according to claim 1, wherein polymer A is obtained by polymerisation of a monomer composition that contains Ai) from 5 to 15 wt. %, of carboxylic acid functional olefinically unsaturated monomer; and Aii) from 85 to 95 wt. % of at least one olefinically unsaturated monomer different than Ai) where the amount is given relative to the total weight of monomers charged for the preparation of Polymer A and whereby Ai) and Aii) add up to 100 wt. %.

9. A process according to claim 1, wherein Polymer B has an acid value of no more than 6.5 mg KOH/g of solid Polymer B, more preferably less than 1 mg KOH/g of solid Polymer B, even more preferably Polymer B has an acid value of 0 mg KOH/g of solid Polymer B.

10. A process according to claim 1, where from 40 to 100 mol % of the total amount of carboxylic acid groups present in Polymer A and Polymer B are neutralized during or following the steps A and/or B.

11. A process according to claim 1, in which; a) the Polymer A has a T.sub.g from 40° C. to 125° C., preferably from 55° C. to 125° C., and more preferably from 70° C. to 125° C.; and b) the T.sub.g of Polymer B is at least 25° C. below the T.sub.g of polymer A, preferably at least 40° C. below the T.sub.g of polymer A, more preferably at least 60° C. below the T.sub.g of polymer A, even more preferably at least 80° C. below the T.sub.g of polymer A.

12. A process according claim 1, in which; a) the Polymer A has a T.sub.g<50° C., preferably from −75° C. to 45° C., preferably from −50° C. to 20° C.; and b) the T.sub.g of Polymer B is at least 25° C. higher than the T.sub.g of polymer A, preferably at least 40° C. higher than the T.sub.g of polymer A, more preferably at least 60° C. higher than the T.sub.g of polymer A, even more preferably at least 80° C. higher than the T.sub.g of polymer A.

13. Process according to claim 1, wherein Polymer A is obtained by emulsion polymerization.

14. Process according to claim 1, wherein the carboxylic acid functional olefinically unsaturated monomers Ai) and Bii) are selected from the group consisting of acrylic acid, methacrylic acid, and β-carboxyethyl acrylate and combinations thereof; more preferably the carboxylic acid functional olefinically unsaturated monomer is methacrylic acid.

15. Process according claim 1, wherein the monomers Aii) and Bi) are selected from the group consisting of acrylates, methacrylates, arylalkylenes and any mixture thereof.

16. Process according to claim 1, wherein at least a part of the monomers Aii) and Bi) contain functional groups for imparting crosslinkability when the aqueous binder composition is subsequently dried.

17. Process according to claim 1, wherein the weight average molecular weight of Polymer A is less than 100 kDalton and higher than 2 kDalton, preferably less than 75 kDalton, more preferably less than 50 kDalton.

18. An aqueous binder composition obtained as claimed in claim 1.

19. An aqueous binder composition comprising polymer C obtained as claimed in claim 1, wherein the amount of polymer C is at least 10 wt. %, preferably at least 15 wt. %, more preferably at least 20 wt. %, even more preferably at least 25 wt. % and at most 90 wt. %, preferably at most 85 wt. % (amount is given relative to the total amount of binders in the aqueous binder composition).

20. An aqueous coating composition comprising an aqueous binder which is prepared according to the process described in claim 1.

21. A method of protective coating a substrate comprising the steps of (1) applying the aqueous coating composition from claim 20 to a substrate comprising a lignocellulosic material and/or aged alkyd resin and/or plastic and/or metallic substrate and/or composite materials comprising glass, to form a coating thereon and (2) drying the coating to form a coated substrate.

Description

EXPERIMENTS AND EXAMPLES

Preparation of Polymer A-Polymer B Emulsion 1

[0109] To a round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple are added 858.3 parts of demineralized water, 0.94 parts of sodium bicarbonate, and 2.91 parts of Fosfodet FAZ109V. The reactor contents are heated to 70° C.

[0110] As soon as the temperature of 70° C. is reached, 5% of a first monomer feed, consisting of 204.4 parts of demineralized water, 0.46 parts of sodium bicarbonate, 8.75 parts of Fosfodet FAZ109V, 361.2 parts of methyl methacrylate, 28.0 parts of methacrylic acid, 77.1 parts of ethyl acrylate, and 7.0 parts of lauryl mercaptan, is added, and the reactor contents are further heated to 80° C. At 80° C. a solution of 0.4 parts of sodium persulphate in 27.6 parts of demineralized water is added. The mixture is stirred for 5 minutes, after which the temperature is further increased to 85° C. At 85° C. feeding the remainder of the monomer feed and an initiator feed, consisting of 1.0 part of sodium persulphate and 64.3 parts of demineralized water, are started. The monomer feed should take 60 minutes, while the initiator feed should take 70 minutes. After completion of both feeds, the temperature is maintained at 85° C. for 30 minutes. The batch is cooled to 80° C. and 48.5 parts of a 25% ammonia solution pre-mixed with 48.5 parts of demineralized water are added in 10 minutes. The batch is further cooled to 30° C. and the solids contents of the first polymerization stage are adjusted to 27.5% with demineralized water.

[0111] 509.0 parts of the reactor phase are transferred to a new round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple, together with 27.4 parts of demineralized water and 0.8 parts of sodium persulphate (free radical initiator). 10% of a second monomer feed, consisting of 41.1 parts of demineralized water, 763.6 parts of the product of the first polymerization stage, 315.7 parts of n-butyl methacrylate, 4.0 parts of n-butyl acrylate, 9.9 parts of diacetone acrylamide, and 0.4 parts of Amietol M21, is added, after which the reactor contents are heated to 85° C. Before addition of the second monomer feed addition the mixture should be homogeneously emulsified.

[0112] As soon as the reaction temperature of 85° C. is reached, a start is made with the addition of the remainder of the remainder second monomer feed. This should take 90 minutes. Simultaneously, a second initiator feed, consisting of 48.2 parts of demineralized water and 1.2 parts of sodium persulphate, is started, and which should take 100 minutes.

[0113] After completion of the monomer feed, the feed vessel is rinsed with 55.1 parts of demineralized water and the reaction temperature of 85° C. is maintained for 30 minutes.

[0114] The reactor contents are cooled to 45° C., after which 4.6 parts of adipic dihydrazide are added. Following stirring at 45° C. for 30 minutes, the reactor contents are cooled to 25° C. The solids content of the emulsion is adjusted to 37.5% using demineralized water.

Preparation of Polymer A-Polymer B Emulsion 2-16

[0115] Following the general recipe described above, the following ingredients are used (if not mentioned in the Table below the amounts are the same as in Emulsion 1).

TABLE-US-00002 TABLE 1a Polymer A-Polymer B emulsion Emulsion 2 3 4 5 6 7 8 9 First monomer feed DAAM 23.3 MMA 361.2 413.0 413.0 320.0 320.0 371.9 371.9 343.5 MAA 28.0 28.0 28.0 56.0 56.0 56.0 56.0 28.0 EA 77.1 25.3 25.3 90.4 90.4 38.5 38.5 71.6 LMKT 16.3 16.3 7.0 16.3 7.0 16.3 7.0 16.3 Ammonia addn. 25% ammonia 48.5 48.5 48.5 97.0 97.0 97.0 97.0 48.5 soln. Reactor contents Demin. Water 262.6 164.4 249.2 10.2 207.5 19.4 207.3 38.4 1.sup.st polym stage 194.6 234.8 196.8 519.1 238.6 517.0 250.0 481.4 Second monomer feed Demin. Water 393.9 383.7 373.8 15.3 311.2 29.1 311.0 89.7 1.sup.st polym stage 291.9 352.2 295.2 778.6 357.9 775.6 374.9 722.0 BMA 258.9 257.1 481.8 301.1 235.3 161.8 505.1 146.0 BA 252.7 250.9 19.2 12.0 265.8 157.9 6.4 164.9 DAAM 15.8 15.7 15.8 9.9 15.8 9.9 15.8 9.8 MAA 10.6 6.6 10.6 6.5 ADH 7.3 14.3 7.3 4.6 14.4 14.4 14.4 14.3

TABLE-US-00003 TABLE 1b Emulsion 10 11 12 13 14 15 16 First monomer feed DAAM 23.3 23.3 23.3 23.3 23.3 23.3 23.3 MMA 343.5 395.0 395.0 302.1 302.1 353.9 253.9 MAA 28.0 28.0 28.0 56.0 56.0 56.0 56.0 EA 71.6 20.0 20.0 85.0 85.0 33.2 33.2 LMKT 7.0 16.3 7.0 16.3 7.0 16.3 7.0 Ammonia addn. 12.5% ammonia 48.5 48.5 48.5 97.0 97.0 97.0 97.0 soln. Reactor contents Demin. Water 194.0 37.1 164.4 185.9 184.4 1.sup.st polym stage 195.3 483.1 234.8 206.2 566.6 208.3 569.9 Second monomer feed Demin. Water 452.8 86.5 383.7 433.8 430.2 1.sup.st polym stage 293.1 724.7 352.2 309.3 850.0 312.4 854.8 BMA 478.3 313.5 257.1 501.6 157.2 232.5 286.4 BA 19.1 4.0 250.9 6.3 153.4 264.5 11.4 DAAM 15.7 9.8 15.7 15.7 9.6 15.8 9.4 MAA 10.5 10.5 6.3 ADH 14.3 14.3 14.3 14.3 14.0 14.4 13.7

Example 1: Imination of Polymer A-Polymer B Emulsion 1

[0116] To a round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple are added 1500 parts of the Polymer A-Polymer B emulsion 1. The required (such to obtain the desired PI/acid ratio) amount of propylene imine added is calculated by taking the total mass of methacrylic acid used for the 1500 parts, dividing this by the molecular weight of methacrylic acid, and multiplying this by the molecular weight of propylene imine times the propylene imine to acid ratio (in this example 0.2). Hence, in this case (16.8/86)*(59*0.2)=2.3 parts. In each example, propylene imine was diluted to 50% with demineralized water prior to addition.

[0117] The reactor contents are heated to 70° C., after which the propylene imine-water mixture is added over a period of 90 minutes. At the end of the addition, the temperature of 70° C. is maintained until the residual propylene imine level is less than 1 ppm. The batch is cooled to room temperature and filtered.

Examples 2-16

[0118] Following the general recipe from Example 1, the following ingredients are used. See Table 2.

TABLE-US-00004 TABLE 2a Example 2 3 4 5 6 7 8 9 O/P emulsion 2 3 4 5 6 7 8 9 PI/acid ratio 0.2 0.8 0.2 0.2 0.8 0.8 0.8 0.2

TABLE-US-00005 TABLE 2b Example 10 11 12 13 14 15 16 O/P emulsion 10 11 12 13 14 15 16 PI/acid ratio 0.8 0.8 0.8 0.2 0.8 0.8 0.2
Table 3 below gives an overview of the measured specifications of the Polymer A-Polymer B emulsions 1-16 prepared as described above; Polymer B has a higher weight average M.sub.w than Polymer A.

TABLE-US-00006 TABLE 3 % of carboxylic acid (and Polymer A (‘oligomer”) specifications Polymer B specifications carboxylate Weight Acid X-linking Acid salt groups) Polymer A- average monomer monomer monomer PolA/PolB Surfactant reacted with polymer B MW Tg conc. conc. Tg conc. ratio conc. propylene emulsion (kD) (° C.) (wt. %) (wt %) (° C.) (wt %) (s/s-wt. %) (wt. %) imine 1 24 80 6 0 20 0 51.2/48.8 0.10 20 2 12 80 6 0 −20 0 20.2/79.8 0.04 20 3 12 100 6 0 −20 0 23.5/76.5 0.05 80 4 23 100 6 0 20 2 20.4/79.6 0.04 20 5 12 80 12 0 20 2 51.8/48.2 0.10 20 6 22 80 12 0 −20 2 23.6/76.4 0.05 80 7 11 100 12 0 −20 0 51.7/48.3 0.10 80 8 20 100 12 0 20 0 24.5/75.5 0.05 80 9 12 80 6 5 −20 2 50.1/49.9 0.09 20 10 23 80 6 5 20 2 20.4/79.6 0.04 80 11 13 100 6 5 20 0 50.2/49.8 0.09 80 12 22 100 6 5 −20 0 23.5/76.5 0.05 20 13 12 80 12 5 20 0 21.2/78.8 0.04 20 14 22 80 12 5 −20 0 54.7/45.3 0.11 80 15 11 100 12 5 −20 2 21.4/78.6 0.04 80 16 20 100 12 5 20 2 55.4/44.6 0.11 20

Comparative Experiment 1=Polymer A-Polymer B Emulsion 1

Comparative Experiment 2

[0119] Preparation of Polymer A-Polymer B Emulsion with Low Acid Value

[0120] To a round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple are added 858.3 parts of demineralized water, 0.94 parts of sodium bicarbonate, and 2.91 parts of Fosfodet FAZ109V. The reactor contents are heated to 70° C.

[0121] As soon as the temperature of 70° C. is reached, 5% of a first monomer feed, consisting of 204.4 parts of demineralized water, 0.46 parts of sodium bicarbonate, 8.75 parts of Fosfodet FAZ109V, 401.0 parts of methyl methacrylate, 18.7 parts of methacrylic acid, 46.6 parts of butyl methacrylate, and 7.0 parts of lauryl mercaptan, is added, and the reactor contents are further heated to 80° C. At 80° C. a solution of 0.4 parts of sodium persulphate in 27.6 parts of demineralized water is added. The mixture is stirred for 5 minutes, after which the temperature is further increased to 85° C. At 85° C. feeding the remainder of the monomer feed and an initiator feed, consisting of 1.0 part of sodium persulphate and 64.3 parts of demineralized water, are started. The monomer feed should take 60 minutes, while the initiator feed should take 70 minutes. After completion of both feeds, the temperature is maintained at 85° C. for 30 minutes. The batch is cooled to 80° C. and 48.5 parts of a 25% ammonia solution pre-mixed with 48.5 parts of demineralized water are added in 10 minutes. The batch is further cooled to 30° C. and the solids contents of the first polymerization stage are adjusted to 27.5% with demineralized water. The amount of methacrylic acid (monomer Ai)) is 4 wt. % (relative to the total weight of monomers charged for the preparation of polymer A). The obtained Polymer A has an acid value of 26 mg KOH/g of solid Polymer A.

[0122] 509.0 parts of the reactor phase are transferred to a new round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple, together with 27.4 parts of demineralized water and 0.8 parts of sodium persulphate (free radical initiator). 10% of a second monomer feed, consisting of 41.1 parts of demineralized water, 763.6 parts of the product of the first polymerization stage, 315.7 parts of n-butyl methacrylate, 4.0 parts of n-butyl acrylate, 9.9 parts of diacetone acrylamide, and 0.4 parts of Amietol M21, is added, after which the reactor contents are heated to 85° C. Before addition of the second monomer feed addition the mixture should be homogeneously emulsified.

[0123] As soon as the reaction temperature of 85° C. is reached, a start is made with the addition of the remainder second monomer feed. This should take 90 minutes. Simultaneously, a second initiator feed, consisting of 48.2 parts of demineralized water and 1.2 parts of sodium persulphate, is started, and which should take 100 minutes.

[0124] After completion of the monomer feed, the feed vessel is rinsed with 55.1 parts of demineralized water and the reaction temperature of 85° C. is maintained for 30 minutes.

[0125] The reactor contents are cooled to 45° C., after which 4.6 parts of adipic dihydrazide are added. Following stirring at 45° C. for 30 minutes, the reactor contents are cooled to 25° C. The obtained Polymer B has an acid value of 0 mg KOH/g of solid Polymer B.

[0126] The amount of Fosfodet FAZ109V surfactant applied is 0.25 wt. % based on the total weight of monomers charged for the preparation of polymer A and polymer B.

[0127] During the polymerization of the second monomer feed an increasing amount of sediment is observed, both on the reactor wall and stirrer. The resulting polymer emulsion shows a lot of sediment upon filtration, the reactor wall and stirrer are extremely polluted with polymer sediment.

[0128] This comparative experiment shows that a stable polymer emulsion cannot be obtained when the acid value of the Polymer A-Polymer B emulsion is too low and a limited amount of added surfactant is applied.

Comparative Experiments 3-5

[0129] These comparative experiments serve to show that introducing amine groups in the Polymer A via the way as described in this invention cannot be achieved by copolymerizing tertiary amine functional monomers and acid functional monomers. For this purpose dimethylaminoethyl methacrylate (DMAEMA) was copolymerized together with methacrylic acid (MAA) in Example 1. All these attempts failed resulting in massive coagulation already after between 5 and 15 minutes after starting the monomer feed of Polymer A, see Table 5.

Comparative Experiment 3

[0130] To a round bottom flask equipped with stirrer, condenser, nitrogen adapter and a thermocouple are added 858.3 parts of demineralized water, 0.94 parts of sodium bicarbonate, and 2.91 of Fosfodet FAZ109V. The reactor contents are heated to 70° C.

[0131] As soon as the temperature of 70° C. is reached, 5% of a first monomer feed, consisting of 204.4 parts of demineralized water, 0.46 parts of sodium bicarbonate, 8.75 parts of Fosfodet FAZ109V, 327.6 parts of methyl methacrylate, 28.0 parts of methacrylic acid, 37.3 parts of diacetone acrylamide, 56.4 parts of ethyl acrylate, 17.0 parts of dimethylaminoethyl methacrylate, and 21.0 parts of lauryl mercaptan, is added, and the reactor contents are further heated to 80° C. At 80° C. a solution of 0.4 parts of sodium persulphate in 27.6 parts of demineralized water is added. The mixture is stirred for 5 minutes, after which the temperature is further increased to 85° C. At 85° C. a start is made with feeding the remainder of the monomer feed and an initiator feed, consisting of 1.0 part of sodium persulphate and 64.3 parts of demineralized water, are started. The monomer feed should take 60 minutes, while the initiator feed should take 70 minutes. Already after 5 minutes the reactor contents are completely gelled, showing that the combination of amine groups and carboxylic acid groups incorporated in a single polymer is not feasible.

Comparative Experiment 4-5

[0132] Following the general recipe described in comparative experiment 1, the following ingredients are used (if not mentioned in the Table below the amounts are the same as in Comparative experiment 1).

TABLE-US-00007 TABLE 4 Comparative Experiment # 4 5 First monomer feed DAAM 37.3 37.3 MMA 319.9 312.2 MAA 18.7 9.3 DMAEMA 34.0 51.1 EA 56.4 56.4 LMKT 21.0 21.0
In Comparative example 4 the reactor contents gelled 10 minutes after starting the monomer feed, while in Comparative example 5 the reactor contents gelled after 15 minutes after starting the monomer feed.
The wet adhesion test results and the colloidal stability assessment of comparative experiment 1 and examples 1-16 are shown in Table 5

TABLE-US-00008 TABLE 5 Example Wet adhesion Colloidal stability Comp Ex 1 (non-iminated PolA- 2 stable PolB emulsion 1) Ex 1 5 stable Ex 2 5 stable Ex 3 5 stable Ex 4 5 stable Ex 5 5 stable Ex 6 5 stable Ex 7 5 stable Ex 8 5 stable Ex 9 5 stable Ex 10 5 stable Ex 11 5 stable Ex 12 5 stable Ex 13 5 stable Ex 14 5 stable Ex 15 5 stable Ex 16 5 stable Comp Ex 2 nd unstable Comp Ex 3 nd nd Comp Ex 4 nd nd Comp Ex 5 nd nd