Method for coating a five-sided container with sag-resistant water-based coating compositions

• US 9,815,083 B2
• Filed: 02/18/2016
• Issued: 11/14/2017
• Est. Priority Date: 03/08/2011
• Status: Active Grant

• Current Assignee: Swimc, LLC (The Sherwin-Williams Company)
• Original Assignee: Valspar Sourcing, Inc. (Sherwin-Williams Company)
• Inventors: Beaudry, Channing Charles, Nowack, William C., Prevost, James A., Zhang, Feng, Wetzel, Wylie H.
• Primary Examiner(s): Fletcher, III, William Phillip
• Application Number:
  US15/046,554
• Publication Number:
  US 20160167085A1
• Time in Patent Office: 635 Days
• Field of Search: 34437, 34439, 34440, 427230-239, 4273722, 427331, 427378, 427384, 220 15, 220600, 220610, 220660
• 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

The present invention provides a water-based coating and/or coating system used to form sag resistant wet layers or coatings on a wide range of substrates. The coating system is effective for protecting metal-containing substrates, such as intermodal cargo containers, against corrosion. As an overview, the present invention provides water-based compositions as primer coats on substrates, and methods for applying the same to substrates. The method includes steps of applying a water-based paint to the interior surfaces of a substrate and drying the substrate by continuously forcing heated air onto the substrate as it moves through a drying chamber. Desirably, the primer incorporates a high level of one or more CAS agents for excellent sag resistance while drying in a broad range of relative humidity environments. Alternatively, modifications can be made to control temperature and humidity during spray application and drying as a way to increase sag resistance of the coating.

Claims

1. A method, comprising:

providing a five-sided container, the container including an open side, a first steel wall opposite the open side, and four steel side walls connected to the first wall, wherein the side walls extend in a first direction with respect to the first wall, and wherein each of the first wall and the four side walls have an interior surface;

applying a water-based paint to the interior surfaces of the first wall and the side walls of the container; and

continuously forcing heated air at a temperature of about 50 to 200°

C. and a velocity of about 0.1 to 10 m/s into the open side of the container as the container moves through a drying chamber to at least partially dry the paint on the interior surfaces of the container, wherein the heated air is directed such that the heated air;

travels in a second direction opposite to the first direction to contact an interior surface of the first wall and flows in a third direction and a fourth direction thereover, wherein the third direction and the fourth direction are substantially opposite one another and substantially normal to the second direction and the first direction;

flows in the first direction along the interior surfaces of the walls of the container; and

exits the container.

2. The method of claim 1, wherein the heated air is forced into the container for less than about 20 minutes.

3. The method of claim 1, wherein applying a water-based paint comprises:

applying at least one primer coat to the interior surfaces of the container, wherein the primer coat comprises a dried coating prepared from a coating composition including

an aqueous carrier;

a first resin component comprising polyvinylidene chloride in admixture with the aqueous carrier;

at least one aqueous epoxy-functional compound; and

one or more fillers; and

optionally, applying at least one topcoat over the primer coat.

4. The method of claim 3 wherein the primer coat has dry film thickness of about 20 to 100 μ

m.

5. The method of claim 1, wherein the five-sided container is an intermodal cargo container.

6. The method of claim 5, wherein the intermodal cargo container substantially conforms to ISO R-668.

7. The method of claim 1, wherein the partially dry paint has a film thickness of 20 to 100 μ

m.

8. A method, comprising:

providing a five-sided container substantially conforming to ISO R-668, the container including an open side, a first steel wall opposite the open side, and four steel side walls connected to the first wall, wherein the side walls extend in a first direction with respect to the first wall, wherein each of the first wall and the four side walls have an interior surface, and wherein the interior surfaces of the first wall of the container and the interior surfaces of at least two side walls of the container intersect to form corner regions;

applying a water-based paint to the interior surfaces of the first wall and the side walls of the container; and

allowing the paint to dry to a film thickness of about 20 to 100 μ

m in an environment having a relative humidity in the range of up to about 95% by forcing heated air into the open side of the container as the container moves through a drying chamber for about 10 to 30minutes, wherein the heated air is directed such that the heated air;

travels in a second direction opposite to the first direction and enters the open side of the container at a velocity sufficient to provide substantially laminar flow along the interior surface of the first wall of the container, and flows in a third direction and a fourth direction thereover, wherein the third direction and the fourth direction are substantially opposite one another and substantially normal to the second direction and the first direction;

flows in the first direction along the interior surfaces of the walls of the container; and

exits the container.

9. The method of claim 8, wherein the relative humidity is in the range of 50% to 85%.

10. The method of claim 8, wherein the relative humidity is in the range of 50% to 75%.

11. A method, comprising:

providing a five-sided container substantially conforming to ISO R-668, the container including an open side, a first steel wall opposite the open side, and four steel side walls connected to the first wall, wherein the side walls extend in a first direction with respect to the first wall, and wherein each of the first wall and the four side walls have an interior surface;

applying a water-based paint as a primer coat to the interior surfaces of the first wall and the side walls of the container in process conditions modified to control humidity and temperature, wherein the water-based paint comprises

an aqueous carrier;

a first resin component comprising polyvinylidene chloride in admixture with the aqueous carrier;

one or more aqueous epoxy-functional compounds;

one or more fillers; and

one or more CAS agents dispersed in the aqueous carrier, wherein the one or more CAS agents are present in a sufficient amount to provide the water-based paint with sag resistance at 80% relative humidity and 25°

C. that is at least 60% of the sag resistance of the water-based paint at 50% relative humidity and 25°

C.; and

forcing heated air into the open side of the container as the container moves through a drying chamber to at least partially dry the paint to a film thickness of about 20 to 100 μ

m on the interior surfaces of the container, wherein the heated air is directed such that the heated air

(i) travels in a second direction opposite to the first direction to contact an interior surface of the first wall and flows in a third direction and a fourth direction thereover, wherein the third direction and the fourth direction are substantially opposite one another and substantially normal to the second direction and the first direction;

(ii) flows in the first direction along the interior surfaces of the walls of the container; and

(iii) exits the container.

12. The method of claim 11, wherein the one or more CAS agents comprise hydrophilic clay and are present in an amount greater than 0.12 kg per 100 L of the water-based paint.

13. The method of claim 11, wherein the one or more CAS agents comprise bentonite.

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

m.

15. The method of claim 11, wherein the water-based paint is substantially free of associative thickener(s).