Method of coating metallic surface with coating having improved sag resistance

• US 10,556,251 B2
• Filed: 10/31/2017
• Issued: 02/11/2020
• Est. Priority Date: 03/08/2011
• Status: Active Grant

• Current Assignee: Swimc, LLC (The Sherwin-Williams Company)
• Original Assignee: Sherwin-Williams Company
• Inventors: Beaudry, Channing Charles, Nowack, William C., Prevost, James A., Zhang, Feng, Wetzel, Wylie H.
• Primary Examiner(s): Fletcher, III, William P
• Application Number:
  US15/799,085
• Publication Number:
  US 20180318874A1
• Time in Patent Office: 833 Days
• Field of Search: 106468, 106DIG 4
• CPC Class Codes: B05B 12/085 responsive to flow or pressure of liquid or other fluent material to be discharged B05B1/3006, B05B1/323, B05B7/1254 take precedence
• CPC Class Codes: B05D 1/02 performed by spraying
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2504/00 Epoxy polymers
• CPC Class Codes: B05D 2520/00 Water-based dispersions
• CPC Class Codes: B05D 3/007 After-treatment
• CPC Class Codes: B05D 3/0413 Heating with air
• CPC Class Codes: B05D 3/0486 Operating the coating or treatment in a controlled atmosphere
• CPC Class Codes: B05D 3/12 by mechanical means
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: B05D 7/227 of containers, cans or the like
• CPC Class Codes: B05D 7/56 Three layers or more
• CPC Class Codes: B65D 1/22 Boxes or like containers with side walls of substantial depth for enclosing contents B65D43/162, B65D81/02, B65D81/3813 take precedence
• CPC Class Codes: B65D 23/02 Linings or internal coatings
• CPC Class Codes: B65D 23/08 Coverings or external coatings wrappers B65D65/00
• CPC Class Codes: B65D 25/14 Linings or internal coatings of containers made by folding or erecting blanks made of paper B65D5/56 ; linings for domestic water storage heaters F24H1/183
• CPC Class Codes: B65D 25/34 Coverings or external coatings of containers made by folding or erecting blanks made of paper B65D5/62; for bottles or jars B65D23/08; wrappers B65D65/00
• CPC Class Codes: B65D 7/06 of polygonal cross-section, e.g. tins, boxes
• CPC Class Codes: B65D 88/121 ISO containers
• CPC Class Codes: B65D 88/123 open top
• CPC Class Codes: B65D 90/02 : Wall construction arrangements of leakage-indicating devices comprising hollow spaces within walls B65D90/501; arrangements of leakage-indicating devices comprising porous spaces or porous layers in walls B65D90/505; arrangements of leakage-indicating devices comprising electrically conductive layers in walls B65D90/513
• CPC Class Codes: C08K 3/346 : Clay
• CPC Class Codes: C08L 63/00 : Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• CPC Class Codes: C09D 127/08 : Homopolymers or copolymers of vinylidene chloride
• CPC Class Codes: C09D 5/024 : characterised by the additives
• CPC Class Codes: C09D 5/04 : Thixotropic paints
• CPC Class Codes: C09D 7/43 : Thickening agents
• CPC Class Codes: F26B 15/16 : the objects or batches of materials being carried by wheeled trucks
• CPC Class Codes: F26B 21/006 : the gas supply or exhaust being effected through hollow spaces or cores in the materials or objects, e.g. tubes, pipes, bottles F26B9/003 and F26B9/103 take precedence
• CPC Class Codes: F26B 2210/12 : Vehicle bodies, e.g. after being painted
• CPC Class Codes: G05D 7/0688 : by combined action on throttling means and flow sources G05D7/0694 takes precedence
• CPC Class Codes: Y02P 20/141 : Feedstock

Abstract

A method for applying a water-based coating and/or coating system to a metallic substrate to form sag resistant coatings is described. The method is particularly effective for protecting metal-containing substrates, such as intermodal cargo containers, against corrosion. The water-based coating includes an aqueous carrier, a resin component in admixture with the aqueous carrier and a high level of one or more CAS agents for excellent sag resistance.

Claims

1. A method of coating a metallic surface of an article, comprising the step of applying onto at least a portion of the substrate having a metallic surface under conditions effective to form a coating, a coating system comprising:

a. an aqueous coating composition, comprising

i. an aqueous carrier;

ii. a resin component in admixture with the aqueous carrier; and

iii. one or more CAS agents dispersed in the aqueous coating composition, wherein the one or more CAS agents are present in an amount greater than 0.12 kg per 100 L of the aqueous coating composition,

wherein the aqueous coating composition has a pH of less than 6.

2. The method of claim 1, wherein the coating has a dry film thickness of about 25 to 130 μ

m.

3. The method of claim 1, wherein the conditions comprise allowing the coating to dry in an environment having a relative humidity in the range of up to 95%, with the coating drying in a time period of about 10 to 30 minutes.

4. The method of claim 1, wherein the metallic surface of the article comprises at least a portion of an intermodal cargo container.

5. The method of claim 1, wherein the one or more CAS agents are present in an amount sufficient to provide the aqueous coating composition with sag resistance at 80% relative humidity and 25°

C. of at least 60% of the sag resistance of the aqueous coating at 50% relative humidity and 25°

C.

6. The method of claim 1, wherein the one or more CAS agents comprise hydrophilic clay.

7. The method of claim 1, wherein the one or more CAS agents comprise organically modified clay.

8. The method of claim 1, wherein the one or more CAS agents comprise bentonite.

9. The method of claim 1, wherein the aqueous coating composition is substantially free of associative sag resistant agent(s).

10. The method of claim 1, wherein the aqueous coating composition includes less than 2 parts by weight associative sag resistant agent(s) per 10 parts by weight of the one or more CAS agents.

11. The method of claim 1, wherein the one or more CAS agents have average particle size of less than 1 μ

m.

12. The method of claim 1, wherein the aqueous coating composition has a Stormer viscosity of about 50 to 90 Krebs units at 25°

C.