A METHOD FOR REDUCING WATER CONTENT OF AN EPOXY OR/AND POLYURETHANE PAINT DISPERSION AND AN EPOXY OR/AND POLYURETHANE PAINT DISPERSION

Abstract

The invention relates to a method for reducing water content of an epoxy or/and polyurethane paint dispersion to be prepared in a sealed and pressurized aerosol can which paint dispersion comprises, —free water of an amount W1, —organic solvent(s) of an amount W2,5-epoxy or/and polyurethane resin of an amount W3, —liquefied propellant of an amount W5, —ketone of an amount W6, —blocked hardener (hardener precursor) of the epoxy or/and polyurethane resin of an amount W4, wherein said blocked hardener compounds of said epoxy or/and 10 polyurethane resin is selected from the group comprising of an aldimine, an enamine, an imine, a Mannich base, a Schiff's base, an oxazolidine or a bisoxazol-idine, and mixtures thereof, —adjuvants, —water scavenger(s), —catalytic amount of a weak acid to shift equilibrium of reversible reaction (I) between the free water present in said dispersion and blocked hardener compounds of the epoxy or/and polyurethane resin back to formation of said initial epoxy or polyure-thane blocked hardener compounds and to prevent formation of the epoxy or/and polyurethane hardener amines: expoxy and/or polyurethane hardener+ketones catalyst expoxy and/or polyurethane+free water (amine) hardener precursor (1). The method comprises a step in which before providing organic solvent into the aerosol can its water content is reduced by admixing reactant with sulfonyl isocya-nate functionality as a water scavenger into said organic solvent.

Claims

1. A method for reducing water content of an epoxy or/and polyurethane paint dispersion to be prepared in a sealed and pressurized aerosol can which paint dispersion comprised: free water of an amount W1; organic solvent(s) of an amount W2; epoxy or/and polyurethane resin of an amount W3; liquefied propellant of an amount W5; ketone of an amount W6; blocked hardener (hardener precursor) compounds of the epoxy or/and polyurethane resin of an amount W4, wherein said blocked hardener compounds of said epoxy or/and polyurethane resin is selected from the group consisting of an aldimine, an enamine, an imine, a ketimine, a Mannich base, a Schiff's base, an oxazolidine or a bisoxazolidine, and mixtures thereof; adjuvants; water scavenger(s); a catalytic amount of a weak acid to shift equilibrium of reversible reaction (I) between the free water present in said dispersion and blocked hardener compounds of the epoxy or/and polyurethane resin back to formation of said initial epoxy or polyurethane blocked hardener compounds and to prevent formation of the epoxy or/and polyurethane hardener amines: ##STR00016## wherein before providing organic solvent into the aerosol can water content of the organic solvent is reduced by admixing reactant with sulfonyl isocyanate functionality as a water scavanger into said organic solvent.

2. The method according to claim 1, wherein after admixing water scavenger into solvent: adjuvants, weak acid and liquid epoxy or/and polyurethane resin is mixed with the solvent to make a liquid mixture and thereafter; blocked hardener (hardener precursor) of the epoxy or/and polyurethane resin is admixed into the liquid mixture to form a paint making dispersion; and the paint making dispersion is directed into an aerosol can; and the propellant is provided into said can and sealing the can.

3. The method according to claim 1, wherein the water scavenger is a reactant with sulfonyl isocyanate functionality, preferably p-toluenesulfonyl isocyanate.

4. The method according to claim 3, wherein the amount of p-toluenesulfonyl isocyanate to be admixed with the organic solvent depends of the water content of the organic solvent and is between 0.2-10% w/w, preferably 0.2-4% w/w.

5. The method according to claim 4, wherein the water content of the organic solvent is 1-6000 ppm, more specifically 100-1000, preferably 200-700 ppm before admixing with p-toluenesulfonyl isocyanate and the water content of the organic solvent is reduced by mixing 10.0-22.0 g, preferably 11-13 g p-toluenesulfonyl sulfonylisocyanate reactant with each gram of water present in said solvent.

6. The method according to claim 4, wherein the amount of water present in organic solvent is estimated or measured.

7. The method according to claim 6, wherein the water content of organic solvent is measured by Karl Fischer titration test.

8. The method according to claim 1, wherein that the water content of organic solvent is reduced from 100-2500 ppm into range of 1-500 ppm, 0-200 ppm or 0-50 ppm by admixing sulfonylisocyanate reactant into the organic solvent.

9. The method according to claim 1, wherein the organic solvent is a solvent system which contains ketone.

10. The method according to claim 9, wherein the organic solvent comprises 1-4 organic solvents.

11. The method according to claim 1, wherein the only water scavenger present in said epoxy or/and polyurethane paint dispersion present in the sealed and pressurized aerosol can is sulfonylisocyanate reactant, preferably p-toluenesulfonyl isocyanate.

12. The method according to claim 11, wherein the amount of p-toluenesulfonyl isocyanate is 0.1-4% w/w calculated from the amount of total epoxy or/and polyurethane paint dispersion in the aerosol can.

13. The method according to claim 1, wherein during entire retention time of said paint dispersion the reversible reaction 2a takes place and prevents the formation of epoxy or/and polyurethane hardener amines and keeps the amount W1 of free water and the amount W2 of said epoxy or/and polyurethane resins and the amount W3 of said hardener precursor of said epoxy or/and polyurethane resins constant between uses.

14. The method defined in claim 1, wherein said reversible reaction 2a takes place between two sequential uses of paint dispersion.

15. The method defined in claim 14, wherein said reversible reaction (2a) enables a retention time up to 3 years preferably up to 5 years.

16. The method according to claim 15, wherein the free water content W1 of the epoxy or/and polyurethane paint dispersion in the aerosol can is between 50-2000 ppm, or between 50-1000 ppm, or between 50-500 ppm.

17. The method defined in claim 1, wherein the weak acid is fatty acid such as oleic acid or carboxylic acid (XCOOH), which fatty acid or carboxylic acid selected from the group having pK.sub.a value in the range from 1.2 to 9, preferably in the range of 1.2-5.2.

18. The method defined in claim 17, wherein the catalytic amount of the weak acid is from 0.001 to 10% by weight (w/w) of the paint dispersion, preferably from 0.05 to 5%, more preferably from 0.05 to 2%.

19. The method defined in claim 17, wherein the weak acid is carboxylic acid selected from the group consisting of: formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, oxalic acid, lactic acid, malic acid, citric acid, benzoic acid, and mixtures thereof.

20. The method defined in claim 17, wherein the weak acid comprises propionic acid, acetic acid, benzoic acid or mixtures thereof.

21. The method defined in claim 1, wherein the resin to be added in said paint dispersion is a polyurethane resin selected from the group consisting of MDI, HDI, IPDI, TDI and phenol blocked TDI prepolymers.

22. The method defined in claim 1, wherein resin to be added in said paint dispersion is epoxy resin selected from the group consisting of an acrylic dispersion or an acrylic emulsion, an alkyd resin, an oil-modified alkyd resin, an epoxy resin, a polyurethane-modified alkyd resin, a styrene-butadiene emulsion, and a styrene-butadiene dispersion.

23. A method of preparing epoxy or/and polyurethane paint dispersion into a sealed and pressurized aerosol can, from which paint dispersion the amount of water has been reduced by means of the method defined in claim 1, which paint dispersion comprises: free water of an amount W1 which amount W1 is between 50-2000 ppm, preferably between 50-1000 ppm from the weight of the paint dispersion; organic solvent(s) of an amount W2; epoxy or/and polyurethane resin of an amount W3; liquefied propellant of an amount W5; ketone of an amount W6; blocked hardener (hardener precursor) compounds of the epoxy or/and polyurethane resin of an amount W4, wherein said blocked hardener compounds of said epoxy or/and polyurethane resin is selected from the group consisting of an aldimine, an enamine, an imine, a Mannich base, a Schiff's base, an oxazolidine or a bisoxazolidine, and mixtures thereof; adjuvants; and water scavenger(s); which paint dispersion additionally comprises: a catalytic amount of weak acid to shift equilibrium of reversible reaction (2a) established between the free water present in said dispersion and blocked hardener compounds of the epoxy or/and polyurethane resin back to formation of said initial epoxy or polyurethane blocked hardener compounds and to prevent formation of the epoxy or/and polyurethane hardener amines according to reversible reaction (2a): ##STR00017## wherein before providing the organic solvent into the aerosol can its water content of the organic solvent is reduced by admixing sulfonyl isocyanate reactant as a water scavenger into said organic solvent; and reacting the reactant with sulfonyl isocyanate functionality with free water supplies additionally sulfonamide into said paint dispersion of an amount W7.

24. The method of preparing a paint film onto a target surface which method comprises preparing epoxy paint dispersion or/and polyurethane paint dispersion into the sealed and pressurized aerosol can according to claim 23, and further comprises spraying epoxy paint dispersion out from the can, thus enabling humidity, present in surrounding environment to react with the epoxy hardener compound having amine functionality to form on the target surface a cured epoxy paint film.

25. The method according to claim 24, wherein after 24 h drying König hardness 63 is achieved when film thickness is 30-40 um.

26. The method of preparing a paint film onto a target surface which method comprises preparing polyurethane paint dispersion into the sealed and pressurized aerosol can according to claim 23 and further comprises spraying polyurethane paint dispersion out from the can, thus enabling humidity, present in the surrounding environment to react with the amine functionality of the polyurethane hardener compound and then to form on the target surface the cured polyurethane paint film.

27. The method defined in claim 26, wherein after 24 h drying at least König hardness 63 is achieved when film thickness is 30-40 um.

28. The method defined in claim 27, wherein gloss 10-100 is achieved.

29. An epoxy or/and a polyurethane paint dispersion in a sealed and pressurized aerosol can from which paint dispersion the amount of water has been reduced by means of the method defined in claim 1, which paint dispersion contains: (a) epoxy or/and polyurethane resin 3-15, % w/w; (b) blocked hardener of epoxy or/and polyurethane resin defined in (a) 1-5% w/w; (c) organic solvent 10-50% w/w; (d) propellant, especially DME 15-40% w/w; (e) color or primer pigments up to 15%; (f) adjuvants up to 5 w/w %; (g) free water 50-2000 ppm, or 50-1000 ppm, or 50-500 ppm; (h) weak acid 0.01-10% w/w, or 0.05-5 w/w, Or 0.05-2% w/w′ which weak acid is carboxylic acid (XCOOH), selected from the group consisting of carboxylic acids which have the pK.sub.a value in the range from 1.2 to 9, preferably 1.2-5.2; (i) sulfonamide, preferably p-toluene sulfonamide, of an amount 0.2-10% w/w, preferably 0.2-4% w/wp; wherein the amount of compounds (a)-(f), (i) adds up to 90% w/w of the total weight of the paint forming solution and the rest of the solution comprises carbinolamines, (h) weak acid, (g) free water and (j) sulfonamide, preferably p-toluene sulfonamide.

30. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the paint forming dispersion includes also other water scavengers than sulfonylisocyanate reactant, which other water scavengers are selected from the group consisting of oxazolidine, zeolite, calcium carbide, activated carbon, silica, activated alumina, CaSO.sub.4, CaO, metal alkoxides and clay.

31. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the paint dispersion adjuvant is selected from the group consisting of a pigment stabilizer, a corrosion inhibitor, a filler, a thickener, a bedding, a drying accelerator, a viscosity regulator, a mold inhibitor, and a foam inhibitor.

32. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the liquified propellant is dimethyl ether (DME).

33. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the imine is a reaction product of ethylenediamine and methyl isobutyl ketone; diethyl ketone-based di-imine, preferably N,N′-di(1-ethylpropylidene)-m-xylylenediamine; or mixtures thereof.

34. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the enamine is a reaction product of 3,3,5-trimethylcyclohexanone with secondary diamines; a reaction product of isophoronediamine and methyl isobutyl ketone; or N,N, bis(1,3-dimethylbutylidine)ethylenediamine

35. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the Mannich base is dimethylaminomethylphenol.

36. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the aldimine is oxazolidine or bisoxazolidine.

37. The epoxy or/and polyurethane paint dispersion defined in claim 36, wherein the aldimine is 3-oxazolidineethanol,2-(1-methylethyl)-,3,3-carbonate or N-butyl-2-(1-ethyl-pentyl)-1,3-oxazolidine.

38. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the solvent or its reaction product is ketone such as acetone, methyl ethyl ketone, butyl acetal or ethyl acetal.

39. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein resin is epoxy resin which is selected from a group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, aliphatic epoxy resin, glycidylamine epoxy resin, and mixtures thereof; or polyurethane resin which is selected from the group consisting of MDI, HDI, IPDI, TDI and phenol blocked TDI prepolymers.

40. The epoxy or/and polyurethane paint dispersion defined in claim 29, wherein the amount of water scavengers to be used for preparing said epoxy or/and polyurethane paint dispersion is such, that in a case paint surface to be made has a high gloss (gloss 70-100), p-toluene sulfonamide 0.2-10% w/w is present, in a case paint surface to be made has a low gloss (gloss 0-10), p-toluene sulfonamide over 10% w/w is present.

41. An epoxy or/and polyurethane paint dispersion in a sealed and pressurized aerosol can from which paint dispersion the amount of water has been reduced by the method defined in claim 1, which paint dispersion contains: (a) epoxy or/and polyurethane resin 3-15, % w/w; (b) oxazolidine 1-5% w/w; (c) organic solvent, which includes ketone 10-50% w/w; (d) DME 15-40% w/w; (e) color or primer pigments up to 15; (f) adjuvants up to 5 w/w; (g) free water 700-1000 ppm; (h) weak acid 0.01-10% w/w, 0.05-5 w/w, or 0.05-2% w/w which weak acid is a carboxylic acid (XCOOH), selected from the group of acids which have the pK.sub.a value in the range from 1.2 to 9, preferably 1.2-5.2; (i) p-toluene sulfonamide of an amount 0.2-10% w/w, or of an amount 0.2-4% w/w wherein the amount of compounds (a)-f), adds up to 90% w/w of the total volume of the paint forming solution and the rest of the paint forming solution comprises carbinolamines, (h) weak acid, (g) free water and (j) sulfonamide, preferably p-toluene sulfonamide.

42. A liquid mixture for preparing an epoxy or/and a polyurethane paint dispersion in a sealed and pressurized aerosol can by using method defined in claim 1, which liquid mixture has been prepared by admixing following chemicals in any order with each other: a solvent, a ketone, a weak acid, a blocked hardener precursor for epoxy resin or/and polyurethane resin having at least amine functionality, wherein said blocked epoxy or/and polyurethane hardener precursor for epoxy resin or/and polyurethane resin is selected from the group consisting of an imine, an enamine, a ketimine, a Mannich base, a Schiff's base, an aldimine, an oxazole preferably an oxazolidine, and mixtures thereof to be used with said weak acid for preventing epoxy resin hardener compounds or/and polyurethane resin hardener compounds to be formed from said blocked epoxy or/and polyurethane hardener precursor, optional epoxy resin is selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, aliphatic epoxy resin, glycidylamine epoxy resin, and mixtures thereof, optional possible polyurethane resin is selected from the group which comprises MDI, HDI, IPDI, TDI and phenol blocked TDI prepolymers wherein said liquid mixture further comprises-free water, brought alongside with said chemicals; and reactant with sulfonyl isocyanate functionality, for reducing free water content of liquid mixture has been admixed into said liquid mixture.

43. The liquid mixture according to claim 42, wherein the amount of free water present in liquid mixture is in a range of 1-10000 ppm, preferably in a range of 1-6500 ppm before adding reactant with sulfonyl isocyanate functionality and in range of 100-2500 after reactant with sulfonyl isocyanate functionality has been reacted with chemicals, preferably with the solvent.

44. The liquid mixture defined in claim 43, wherein the amount of reactant with sulfonyl isocyanate functionality depends on the amount of moisture present in liquid mixture, preferably in solvent(s).

45. The liquid mixture defined in claim 43, wherein then the amount of the of reactant with sulfonyl isocyanate functionality depends also of the amount of adjuvants such as matting agents.

Description

EXAMPLE 1

[0246] PU clear coat Consumer quality

[0247] Gloss (angle 60°) 95-100

[0248] Film thickness 1 cross layer 40 μm

[0249] Adhesion to metal 385 MPa

[0250] Hardness after 24 h ambient 68 König

[0251] Hardness alter 15 min. IR drying 75° C. 78 König

[0252] Hardness after 48H 100

[0253] Pencil Hardness H6 passed

[0254] Water resistance after 1H ambient drying

[0255] Gasoline resistance after 1H ambient drying

EXAMPLE 2

[0256] Pu clear coat semi-gloss

[0257] Gloss (angle 60°) 50-75

[0258] Film thickness 1 cross layer 40 μm

[0259] Adhesion to metal 379 MPa

[0260] Hardness after 24 h ambient 73 König

[0261] Hardness after 15 min. IR drying 75° C. 83 König

[0262] Hardness after 48H 110

[0263] Pencil Hardness H6 passed

[0264] Water resistance after 1H ambient drying

[0265] Gasoline resistance after 1H ambient drying

EXAMPLE 3

[0266] Pu clear coat Matt

[0267] Gloss (angle 60°) 0-15

[0268] Film thickness 1 cross layer 40 μm

[0269] adhesion to metal 389 MPa

[0270] Hardness after 24 h ambient 79 König

[0271] Hardness after 15 min. IR drying 75° C. 88 König

[0272] Hardness after 48H 118

[0273] Pencil Hardness H6 passed

[0274] Water resistance after 1H ambient drying

[0275] Gasoline resistance after 1H ambient drying

EXAMPLE 4

[0276] Primer Epoxy based

[0277] Film thickness 1 cross layer 30 μm

[0278] Adhesion to metal 379 MPa

[0279] Hardness after 24 h ambient 63 König

[0280] Hardness after 15 min. IR drying 75° C. 69 König

[0281] Hardness after 48H 84

[0282] Pencil Hardness H6 passed

[0283] Water resistance after 15 min IR drying

[0284] Gasoline resistance alter 15 min IR drying.

[0285] Sand able after 15 min IR drying

EXAMPLE 5

[0286] Filler Epoxy based

[0287] Film thickness 1 cross layer 40 μm

[0288] Adhesion to metal 379 MPa

[0289] Hardness after 24 h ambient 63 König

[0290] Hardness after 15 min. IR drying 75° C. 69 König

[0291] Hardness after 48H 84

[0292] Pencil Hardness H6 passed

[0293] Water resistance after 15 min IR drying

[0294] Gasoline resistance after 15 min IR drying.

[0295] Sand able after 15 min IR drying

EXAMPLE 6

[0296] Pigmented colored top coat Epoxy based

[0297] Gloss (angle 60°) 95-100

[0298] Film thickness 1 cross layer 40 μm

[0299] Adhesion to metal 415 MPa

[0300] Hardness after 24 h ambient 63 König

[0301] Hardness after 15 min. IR drying 75° C. 69 König

[0302] Hardness after 48H 84

[0303] Pencil Hardness H6 passed

[0304] Water resistance after 15 min IR drying

[0305] Gasoline resistance after 15 min IR drying.

[0306] Sand able after 15 min IR drying

EXAMPLE 7 (GENERAL WORKING EXAMPLE)

[0307] General example for preparing a liquid intermediate product for an aerosol formulation (paint dispersion)

[0308] General Principles:

[0309] The solvents used in the formulations contain water

EXAMPLES

[0310]

TABLE-US-00019 Acetone 1300 ppm Butyl acetate  450 ppm Xylene  150 ppm MPA  700 ppm Methyl Isobutyl Ketone  450 ppm (MIBK) Before mixing in the active ingredients like binder and additives most of the water is removed by chemical reaction p-Tosyl   + H2 sulfoamid + CO2

[0311] Removing the excess amount of water prior adding liquid mixture into an aerosol can is preferably done in following way:

[0312] Water content of solvent(s) and propellant is 500-6000 ppm.

[0313] At least the moisture present in solvent should be reacted away. The water is reacted away by addition of sulfonyl isocyanate. For example, 12-24 gram of p-toluenesulfonyl isocyanate can react 1 gram of water away. The rest products of this moisture removing reaction is CO.sub.2 and an inert sulfonamide.

[0314] Tests had showed that when reacting 10000 ppm of water with sulfonyl-isocyanate the reaction product sulfonamide do not disturb even with high concentrations the film forming process and clear varnish can be prepared The CO.sub.2 will be removed by gently stirring.

[0315] After this process the formulation id finished and filtered (10 μm) before filling in the aerosol can.

[0316] During the finishing of the liquid phase (to be filled in the aerosol can) water will be picked up from the air while the mixing is done under ambient conditions.

[0317] This water will have no influence on the shelf (Shelf life of at least 2 years) life of the end product while there is present in the end product a Ketone. a Carboxylic acid pKa 2.7-5.5. This mixture will provide an environment for the Schiff's base reaction. Resulting in no free amino groups to react with either isocyanate or epoxy components.

[0318] Remark: The water content is determined with Karl fisher coulometer titration

[0319] Water content of the liquid will vary between 200 and 700 ppm resulting in a water content in the end product (liquid phase+liquified propellant) of 120 till 500 ppm.

[0320] Mixing Order and Principles.

[0321] The necessary ketone containing solvents are mixed together for forming solvent system. In a case paint dispersion which will give semi-gloss or matt paint surface (end product) is to be prepared, the necessary matting agents (primer or filler) are dispersed into the solvent system using high shire mixing. The water content of this mixture containing solvent system and possible matting agents is determined by Karl Fisher titration. Based on the determined water content of mixture the amount of sulfonyl-isocyanate is calculated and added to the mixture.

[0322] The reaction between sulfonyl-isocyanate with water present in solvent system and possible mattening agents is ready within approximately 15 minutes.

[0323] Again, a sample is taken and the water content or absent of this solvent system and possible mattening agents is again determined by Karl Fisher titration. If the water content is below 50 ppm the rest of raw materials for making paint, primer or clear coat can be added into said mixture of solvent system and possible mattening agents to make a liquid mixture by stirring gently.

[0324] Due to the fact the liquid mixture to be sealed into an aerosol can is prepared under atmospheric conditions, the following safety net is built into the liquid mixture. The safety is based on the Shiff's base principle that an amine in the presence of a ketone will react to a ketimine/imine in the presence of a catalytic presence of a weak acid. Therefore, acetone and MEK may be used as ketone containing solvents. All blocked hardeners will all form an amine in presence of water and in the case of aldimine and oxazolidine blocked hardener will form and amine and a polyol in the presence of water.

[0325] To avoid the forming of epoxy/polyurethane hardening amines catalytic amount of weak acid (pKa for example 3.5-6) is also added into liquid mixture, to create circumstances for the forming of Shiff's bases. When liquid mixture is filled into an aerosol can weak acid will continuously prevent epoxy resin or/and polyurethane resin hardening compounds. Test have shown that using this principle paint dispersion in the aerosol will be stable of a period of at least 3 years. The threshold value of the water content in the filled product is app. 50-1000 ppm preferable 50 500 ppm. depending on the type of paint dispersion inside the can (epoxy, polyurethane)