PROCESS FOR APPLYING COATING COMPOSITIONS HAVING DIFFERENT LEVELING PROPERTIES AND/OR SAG RESISTANCE TO DIFFERENT TARGET AREAS OF AN OBJECT

Abstract

Described herein is a process for applying at least two coating compositions having different leveling properties and/or a different sag resistance to an object including a plurality of target areas where at least part of the plurality of target areas has different properties. Also described herein are a method of using the inventive process for coating target areas of an object having different orientations relative to each other and a system for applyingutilizing an application deviceat least two coating compositions having different leveling properties and/or a different sag resistance to an object including a plurality of target areas, where at least part of the plurality of target areas having different properties.

Claims

1. A process for applying at least two coating compositions having different leveling properties and/or a different sag resistance to an object comprising a plurality of target areas, at least part of the plurality of target areas having different properties, said process comprising: (a) providing a first coating composition C.sub.1 having specific leveling properties and/or a specific sag resistance, (b) applying the first coating composition C.sub.1 provided in step (a) onto at least part of the plurality of target areas having first properties P.sub.1, and (c) repeating steps (a) and (b) at least once, wherein the specific leveling properties and/or a specific sag resistance of each further coating composition C.sub.x provided upon repeating step (a) differ from the specific leveling properties and/or the specific sag resistance of the previously provided coating composition C.sub.1 and each previously provided further coating composition C.sub.x, and each coating composition C.sub.x is applied onto at least part of the plurality of target areas having properties being different from the properties P.sub.1 and the properties of each further previously coated target areas upon repeating (b).

2. The process according to claim 1, wherein step (a) includes (a-1) providing at least two components (A.sub.i).sub.i=1, . . . , n having different leveling properties and/or a different sag resistance and optionally at least one hardener component B, (a-2) selecting mixing ratio(s) for at least part of the components A.sub.i provided in step (a-1) to achieve specific leveling properties and/or a specific sag resistance of the first coating composition C.sub.1 and/or further coating composition(s) C.sub.x, (a-3) optionally selecting mixing ratio(s) for the at least one hardener component B provided in step (a-1), and (a-4) mixing components A.sub.i, optionally with the at least one hardener component B in the mixing ratio(s) selected in step (a-2) and optionally (a-3) to provide the coating composition C.sub.1 and/or further coating composition(s) C.sub.x specific leveling properties and/or a specific sag resistance.

3. The process according to claim 2, wherein step (a-2) includes determining the required specific leveling properties and/or sag resistance of the first coating composition C.sub.1 and/or further coating composition(s) C.sub.x and selecting a mixing ratio for at least part of the components provided in step (a-1) such that the specific leveling properties and/or the specific sag resistance of the resulting first coating composition C.sub.1 and/or further coating composition(s) C.sub.x is achieved.

4. The process according to claim 3, wherein a higher fraction of components provided in step (a-1) and having a high sag resistance is selected in step (a-2) if a higher sag resistance of the coating composition C.sub.1 and/or further coating composition(s) C.sub.x is required or wherein a lower fraction of components provided in step (a-1) and having a high sag resistance is selected in step (a-2) if higher leveling properties of the first coating composition C.sub.1 and/or further coating composition(s) C.sub.x are required.

5. The process according to claim 1, wherein step (a) includes preparing the first coating composition C.sub.1 and/or further coating composition(s) C.sub.x having specific leveling properties and/or a specific sag resistance by mixing at least two coating material ingredients.

6. The process according to claim 1, wherein the different properties include different orientations of at least two target areas relative to each other.

7. The process according to claim 1, wherein at least one provided coating composition has good leveling properties and at least one further provided coating composition has a good sag resistance.

8. The process according to claim 1, wherein the different leveling properties and/or the different sag resistance of the provided coating compositions are achieved by the presence of at least one sagging control agent (SCA) in at least one provided coating composition.

9. The process according to claim 8, wherein the sagging control agent (SCA) is selected from the group consisting of polymeric sagging control agents.

10. The process according to claim 9, wherein the polymeric sagging control agent (SCA) is obtained by reacting a primary or secondary amine with an isocyanate compound in the presence of a hydroxy-functional poly(meth)acrylate.

11. The process according to claim 7, wherein the sagging control agent (SCA) is present in a total amount of 0.1 to 40 wt.-% based on the total weight of the respective provided coating composition.

12. The process according to claim 1, wherein provided coating compositions having high leveling properties are each applied onto at least part of the horizontally oriented target areas of the object and wherein provided coating compositions having a high sag resistance are each applied onto at least part of the vertically oriented target areas of the object.

13. The process according to claim 1, further including a step (e) of curing or drying and curing the applied the coating composition(s).

14. A method of using the process according to claim 1, the method comprising using the process for coating target areas of a substate having different orientations relative to each other.

15. A system for applyingutilizing an application deviceat least two coating compositions having different leveling properties and/or a different sag resistance to an object comprising a plurality of target areas, at least part of the plurality of target areas having different properties, the system comprising: an application device comprising a nozzle; a storage device for storing application instructions and optionally mixing ratio instructions; one or more data processors configured to execute the application instructions and optionally the mixing ratio instructions to control the application device; and at least two reservoirs in fluid communication with the application device and configured to contain at least two components (A.sub.i).sub.i=1, . . . , n, each component A.sub.i having different leveling properties and/or a different specific sag resistance, and optionally at least one hardener component B or configured to contain at least two coating compositions (C.sub.i).sub.i=1, . . . , n having specific leveling properties and/or a specific sag resistance, wherein the application device is configured to receive the components (A.sub.i).sub.i=1, . . . , n and optionally the hardener component B from the reservoir and to mix the components (A.sub.i).sub.i=1, . . . , n, optionally with the hardener component B based on the mixing ratio instructions within the nozzle, and to expel the resulting coating compositions (C.sub.i).sub.i=1, . . . , n based on the application instruction through the nozzle to at least two target areas having different properties to form at least two coating layers such that at least part of each coating composition C.sub.i is not expelled to the same target area(s) of the object; or wherein the applicator is configured to receive the at least two coating compositions (C.sub.i).sub.i=1, . . . , n from the reservoir, and to expel the coating compositions (C.sub.i).sub.i=1, . . . , n based on the application instruction through the nozzle to at least two target areas having different properties to form at least two coating layers such that at least part of each coating composition C.sub.i is not expelled to the same target area(s) of the object.

16. The process according to claim 9, wherein the polymeric sagging control agent (SCA) is obtained by reacting a benzyl amine, with an isocyanate compound in the presence of a hydroxy-functional poly(meth)acrylate.

17. The process according to claim 9, wherein the polymeric sagging control agent (SCA) is obtained by reacting a primary or secondary amine with a polyisocyanate in the presence of a hydroxy-functional poly(meth)acrylate.

18. The process according to claim 7, wherein the sagging control agent (SCA) is present in a total amount of 2 to 30 wt.-% based on the total weight of the respective provided coating composition.

19. The process according to claim 7, wherein the sagging control agent (SCA) is present in a total amount of 3 to 20 wt.-% based on the total weight of the respective provided coating composition.

20. The process according to claim 7, wherein the sagging control agent (SCA) is present in a total amount of 4 to 15 wt.-% based on the total weight of the respective provided coating composition.

Description

DESCRIPTION OF THE DRAWINGS

[0238] FIG. 1 shows a schematical drawing of a vehicle 100 to be coated with a coating material. In this example, the coating material is a clearcoat material. In another example, the coating material is a primer coating material, a primer-surfacer coating material, a filler coating material or a basecoat material. The vehicle 100 contains horizontally oriented areas 102 to be coated as well as vertically oriented areas 104 to be coated. Using the inventive process to coat the horizontally oriented areas 102 and the vertically oriented areas 104 with coating materials, a coating material having a high sag resistance is applied on the vertically oriented areas 104 whereas a coating material having good leveling properties and low sag resistance is applied on the horizontally oriented area 102. The coating material having a high sag resistance is obtained, for example, by using a component A.sub.i containing a sagging control additive (SCA), such as the coating composition CC1 disclosed in relation to the inventive examples. The coating material having high leveling properties and a low sag resistance is obtained by mixing at least two components A.sub.i, A.sub.i+1 in a defined mixing ratio, wherein one component A.sub.i or A.sub.i+1 contains a sagging control additive (SCA), and the other component A.sub.i+1 or A.sub.i does not contain a sagging control additive (SCA) such that the resulting coating material contains a lower concentration of sagging control additive as compared to the component A.sub.i or A.sub.i+1 containing the sagging control additive (SCA).

EXAMPLES

[0239] The present invention will now be explained in greater detail using working examples, but the present invention is in no way limited to these working examples. Moreover, the terms parts, % and ratio in the examples denote parts by mass, mass % and mass ratio respectively unless otherwise indicated.

A) Methods of Determination

1. Solids Content (Solids, Nonvolatile Fraction)

[0240] Unless otherwise indicated, the solids content, also referred to as solid fraction hereinafter, was determined in accordance with DIN EN ISO 3251:2008-06 at 130 C. and 60 min, initial mass 1.0 g.

2. Sag Resistance on Vertically Oriented Areas

[0241] Determination of sag resistance on vertically oriented areas was done through an application of the coating material in a wedge with a layer thickness from 10 to 50 m onto panels primed with an electrodeposited coating and coated with a basecoat. The basecoat was cured before application of the clearcoat formulation. Sagging occurred on holes in the panels, imitating edges in a car body. Measurand for sagging was the layer thickness, at which sagging length reached 3 mm and 10 mm length.

[0242] In more detail, a perforated steel panel having dimensions of 57 cm20 cm (according to DIN EN ISO 28199-1, section 8.1, version A), coated with a cured cathodic electrodeposition paint (Cathoguard 800 from BASF Coatings GmbH) and with a cured commercially available water-based basecoat material (ColorBrite from BASF Coatings GmbH) was prepared analogously to DIN EN ISO 28199-1, section 8.2 (version A). The clearcoat material was then electrostatically applied in the form of wedges with a target film thickness (film thickness of the dried material) of 10 m to 50 m in a single application in a method based on DIN EN ISO28199-1, section 8.3. After a flash time of 10 minutes at room temperature (25 C.), the resulting clear coating film was cured in a forced air oven at 140 C. for 20 minutes. The steel panels were flashed and cured while standing upright.

[0243] The sag resistance was determined in each case according to DIN EN ISO 28199-3, section 4. Measurand for sag resistance was the layer thickness at which the sagging length reached 3 mm and 10 mm length.

3. Measurement of DOI

[0244] The DOI was evaluated at a dry film thickness of 30 to 35 micrometer using a model D 47-6 DOI meter from Hunter Dorigon of Fairfax, Va., per ASTM D-5767-18 after preparing the coating as described below.

4. Wavescan Measurements

[0245] Wavescan measurements were performed at a dry film thickness of 30 to 35 micrometer on a Wave-scan Plus 4806 meter from BYK Gardner, per GM4364M after preparing the coating as described below. The shortwave and longwave values are the average of three readings.

5. Overspray Compatibility

[0246] The overspray compatibility of different clearcoat compositions was determined as follows:

[0247] A steel panel coated with a cured cathodic electrodeposition paint (Cathoguard 800 from BASF Coatings GmbH) and with a cured commercially available water-based basecoat material (ColorBrite from BASF Coatings GmbH) was electrostatically coated with the first clearcoat composition in a target film thickness (film thickness of the dried material) of 40 m5 m in a single application. Afterwards, half of the panel was manually coated with the second clearcoat composition in a single slow hit with an assumed target film thickness (film thickness of the dried material) of 10 m. After a flash time of 10 minutes at room temperature (25 C.), the resulting clear coating films were cured in a forced air oven at 140 C. for 20 minutes.

[0248] The resulting panel is visually evaluated for surface defects like e.g. matte/dull areas. If the clearcoat layers are visually ok and glossy, the panel is rated i.O. (Okay). Otherwise, the panel is rated n.i.O. (not okay).

B) Preparation of Different Clearcoat Coating Compositions

1. Preparation of Components Provided in Step (a) of the Inventive Process

[0249] Each component A1 and A2 was prepared by mixing the components given in Table 1. Component A1 contains a high amount of sagging control agent (SCA) while component A2 does not contain a sagging control agent. Solvent naphtha is used in component A2 to compensate the residual amount such that each component A1 and A2 equals to 100.

TABLE-US-00001 TABLE 1 Ingredients to prepare the component A1 and A2 (all amounts are given in % by weight) Ingredients A1 A2 (Meth)acrylic resin 1 .sup.1) 47.7 47.7 Polymeric sagging additive .sup.2) 17 (Meth)acrylic resin 2 .sup.3) 15.4 Solventnaphtha 160/180 1.56 SETAMINE US-138 BB-70 .sup.4) 9.0 9.0 CYMEL 303 LF Resin .sup.5) 1.9 1.9 Setal 1715 .sup.6) 4.9 4.9 UV-Absorber 1130 .sup.7) 1.29 1.3 HALS 292 .sup.8) 0.97 0.97 BYK-325 N .sup.9) 0.20 0.20 BYK 315 N .sup.10) 0.03 0.03 Butylglycol acetate 1.0 1.0 Xylene 0.97 0.97 Flowlen AC 300 .sup.11) 0.04 0.04 Xylene 3.6 3.6 Butylglycol acetate 4.8 4.8 Butyldiglycol acetate 0.8 0.8 Butanol 5.8 5.8 .sup.1) the hydroxy-functional (meth)acrylic resin contains the following monomers: styrene, hydroxyethyl methacrylate, hydroxypropyl methacrylate, butyl methacrylate, cyclohexyl methacrylate and acrylic acid, solids content = 56%, .sup.2) prepared according to the procedure described under Herstellung eines erfindungsgemen SCA Harzes on page 18, lines 5 to 26 of WO2008148555A1, .sup.3) prepared according to the procedure described under Herstellung eines erfindungsgemen SCA Harzes on page 18, lines 5 to 17 of WO2008148555A1, .sup.4) n-butylated high imino melamine crosslinker, solids content = 68-72% (supplied by Allnex); .sup.5) highly methylated, monomeric melamine crosslinker, solids content = 98% (supplied by Allnex); .sup.6) saturated polyester having an OH content of 4.4%, based on solids, a solids content of 71-73%, an acid number of from 6.5 to 9.8, a viscosity from 4.0 to 5.8 Pas at 23 C. and 100 s.sup.1 (supplied by Allnex); .sup.7) liquid UV absorber of the hydroxyphenyl benzotriazole class (supplied by BASF Dispersions & Resins); .sup.8) liquid hindered amine light stabilizer (Tinuvin 292) (supplied by BASF Dispersions & Resins); .sup.9) polyether-modified polymethylalkylsiloxane, solid content = 52% (supplied by BYK-Chemie GmbH); .sup.10) polyester-modified polymethylalkylsiloxane, solid content = 25% (supplied by BYK-Chemie GmbH); .sup.11) Acrylic polymer/polyvinylether, solid content = 77% (supplied by Kyoeisha Chemical)

2. Preparation of the Hardener Component

[0250] The hardener component B was prepared by mixing the components given in Table 2:

TABLE-US-00002 TABLE 2 Ingredients to prepare the hardener component B Ingredients Amount [wt.-%] Polyisocyanate .sup.1) 89.6 Solventnaphtha 160/180 5.2 Butylacetate 5.2 .sup.1) Desmodur Ultra N 3390 BA/SN, solid content = 90% (supplied by Covestro AG)

3 Preparation of Different Clearcoat Coating Compositions

[0251] The clearcoat compositions CC1 to CC3 were each prepared by mixing the respective component A1 and A2 or a mixture of components A1 and A2 with the hardener component B in the mixing ratios given in Table 3.

TABLE-US-00003 TABLE 3 Clearcoat composition CC1 to CC3 Clearcoat Component Mixing ratio Mixing ratio compositions (a) A1:A2 (a):B CC1 A1 100:33 CC2 A1 and A2 1.1 100:33 CC3 A2 100:33

C) Preparation of Coated Objects

1. Preparation of Coated Substates for Evaluation of Sag Resistance:

[0252] Test panels for evaluation of sag resistance were prepared as described in point A) 2. above.

2. Preparation of Coated Objects for Evaluation of Horizontal Appearance

[0253] Test panels for the evaluation of horizontal appearance were prepared by coating steel panels coated with a cured cathodic electrodeposition paint (Cathoguard 800 from BASF Coatings GmbH) and with a cured commercially available black basecoat material (ColorBrite from BASF Coatings GmbH) with the respective clearcoat composition CC1 to CC3 in a wedge application of 0 m to 60 m using ESTA HR Application. After a flash time of 10 minutes at room temperature (25 C.), the resulting clear coating film was cured in a forced air oven at 140 C. for 20 minutes.

3. Preparation of Coated Objects for Evaluation of Overspray Compatibility

[0254] Test panels for the evaluation of overspray compatibility were prepared as described in point A) 5. above.

D) Results

1. Sag Resistance

[0255] The sag resistance of clearcoat compositions CC1 to CC3 was determined as previously described. The obtained results are listed in Table 4. In the upper half of this table, only the differences with regard to the ingredients clearcoats CC1 to CC3 are listed. The footnotes 1) to 3) are corresponding to footnotes 1) to 3) of Table 1.

TABLE-US-00004 TABLE 4 Results of sag resistance for clearcoats CC1 to CC3 Ingredient CC1 CC2 CC3 (Meth)acrylic resin 1 .sup.1) 47.7 47.7 47.7 Polymeric sagging additive .sup.2) 17 8.5 (Meth)acrylic resin 2 .sup.3) 7.7 15.4 Solventnaphtha 160/180 0.78 1.56 Sagging start [m] 37 29 31 3 mm Sagging length [m] 47 43 44 10 mm Sagging length [m] 59 50 48

2. Leveling Properties

[0256] The leveling properties of clearcoat compositions CC1 to CC3 was determined as previously described. The obtained results are listed in Table 5. In the upper half of this table, only the differences with regard to the ingredients clearcoats CC1 to CC3 are listed. The footnotes 1) to 3) are corresponding to footnotes 1) to 3) of Table 1.

TABLE-US-00005 TABLE 5 Leveling properties for clearcoats CC1 to CC3 Ingredient CC1 CC2 CC3 (Meth)acrylic resin 1 .sup.1) 47.7 47.7 47.7 Polymeric sagging additive .sup.2) 17 8.5 (Meth)acrylic resin 2 .sup.3) 7.7 15.4 Solventnaphtha 160/180 0.78 1.56 Longwave values [30-35 m] 8.9 5.5 5.4 Shortwave values [30-35 m] 8.7 8.6 8 DOI [30-35 m] 96.2 96.2 96.1

3. Overspray Compatibility

[0257] The overspray compatibility of clearcoat compositions CC1 to CC3 was determined as previously described. The obtained results are listed in Tables 6 and 7. In the upper half of this table, only the differences with regard to the ingredients clearcoats CC1 to CC3 are listed. The footnotes 1) to 3) are corresponding to footnotes 1) to 3) of Table 1.

TABLE-US-00006 TABLE 6 Overspray compatibility for clearcoats CC1 to CC3 on horizontally oriented object First layer on horizontal object Ingredient CC1 CC2 CC3 (Meth)acrylic resin 1 .sup.1) 47.7 47.7 47.7 Polymeric sagging 17 8.5 additive .sup.2) (Meth)acrylic resin 2 .sup.3) 7.7 15.4 Solventnaphtha 160/180 0.78 1.56 Overspray CC1 Not OK Not OK horizontal CC2 OK Not OK CC3 Not OK OK

TABLE-US-00007 TABLE 7 Overspray compatibility for clearcoats CC1 to CC3 on vertical oriented object First layer on vertical object Ingredient CC1 CC2 CC3 (Meth)acrylic resin 1 .sup.1) 47.7 47.7 47.7 Polymeric sagging 17 8.5 additive .sup.2) (Meth)acrylic resin 2 .sup.3) 7.7 15.4 Solventnaphtha 160/180 0.78 1.56 Overspray CC1 Not OK Not OK vertical CC2 OK Not OK CC3 Not OK OK

E) Discussion of the Results

[0258] The highest sag resistance on vertically oriented objects is obtained for clearcoat composition CC1 containing high amounts of sagging control agent (SCA) (see Table 4). By mixing component A1 containing high amounts of sagging control agent (SCA) with component A2 being free of sagging control agents (SCAs), the sagging resistance on vertically oriented objects was significantly reduced. This is due to the reduced amount of sagging control agent.

[0259] However, the leveling properties of the clearcoat composition CC2 on horizontally oriented objects was significantly improved by mixing SCA-containing component A1 with SCA-free component A2 and the obtained clearcoat composition CC2 even has better leveling properties than the SCA-free clearcoat composition CC3 (see Table 5). Thus, by selecting an appropriate mixing ratio in step (b) of the inventive process, the leveling properties and sag resistance of the clearcoat compositions can be adjusted to achieve either high sag resistance for vertically oriented objects or good leveling properties for horizontally oriented objects. Since the mixing ratio can be dynamically adjusted in step (b) if, for example, an application nozzle (such as the EcoBell 3 2X2K manufactured by company Drr) allowing attachment of 3 reservoirs containing component A1, A2 and hardener B is used, objects containing horizontally as well as vertically oriented surfaces can be coated in a high quality because the sag resistance and leveling properties can be adjusted depending on the orientation of the surface during application of the clearcoat composition. The high compatibility upon mixing of the components A1 and A2 is achieved by using the same binder in component A2 which is used to prepare the sagging control agent to compensate the absence of the SCA. Moreover, components A1 and A2 only differ in the presence of the SCA while all other ingredients and their amounts are kept constant to avoid an undesired negative influence on the quality of the resulting clearcoat layer due to incompatibilities occurring upon mixing of the components A1 and A2.

[0260] To achieve a high optical quality without a negative influence due to incompatibilities of the different clearcoat compositions, the clearcoat compositions have to be applied in a defined order, as is demonstrated by the overspray compatibility studies. According to the results demonstrated in Tables 6 and 7, a high compatibility (i.e. no negative influence on the optical quality of the resulting clearcoat layer achieved by applying clearcoat composition CC1 as well as CC2) is achieved if clearcoat composition CC1 is first applied on vertically oriented objects and afterwards, clearcoat composition CC2 is applied on horizontally oriented objects.