Powder Coating Composition

Patent metadata

Field	Value
Publication number	US-2017158869-A1
Application number	US-201715434862-A
Country	US
Kind code	A1
Filing date	Feb 16, 2017
Priority date	Aug 20, 2014
Publication date	Jun 8, 2017
Grant date	—

Abstract

A coating composition comprising a blend of one or more polyester resins and a low molecular weight highly functional resin component is described herein, where the coating composition is in the form of a powder and is configured to form a thin coating that demonstrates optimal adhesion to the substrate.

First claim

What is claimed is:

1 . A method for forming a coating on a substrate, the method comprising:
providing a powder coating composition comprising:
at least one polyester having a weight-average molecular weight ranging from about 20,000 to about 50,000; and
about 1 to 5% of a low molecular weight highly functional resin component;
applying the coating composition to at least one portion of the substrate; melting the coating composition on the at least one portion of the substrate; and solidifying the molten coating composition to form the coating adhered to the at least one portion of the substrate, wherein the coating demonstrates optimal adhesion to the at least one portion of the substrate.

2 . The method of claim 1 , wherein the highly functional resin component is a polymer derived from a monomeric unit comprising a glycidyl ester of an α,β-unsaturated acid or anhydride thereof.

3 . The method of claim 2 , wherein the highly functional resin component is a polymer derived from a monomeric unit comprising a glycidyl ester of (meth)acrylic acid.

4 . The method of claim 2 , wherein the highly functional resin component is a polymer derived from glycidyl methacrylate.

5 . The method of claim 1 , wherein the resin component is derived from a monomeric unit having the structure:

wherein R 1 is —H or —CH 3 , and R 2 is a C1-C16 alkyl group.

6 . The method of claim 1 , wherein the resin component has weight average molecular weight (M,) of about 3000 to about 10,000.

7 . The method of claim 1 , wherein the resin component has weight average molecular weight (M,) of about 4000 to 8000.

8 . The method of claim 1 , wherein the step of providing a coating composition further comprises:
compounding together the at least one polyester resin and the resin additive to form a mixture; and milling the mixture to obtain a powder composition with particle size such that 99% of particles in the powder composition can pass through a 100 μm sieve.

9 . The method of claim 8 , wherein the mixture formed by compounding together the at least one polyester resin and the resin additive further comprises one or more colorants, one or more fillers and one or more flow control agents.

10 . The method of claim 8 , wherein the step of compounding further comprises using an extruder cooled to a temperature of about 150° C. to 220° C.

11 . The method of claim 1 , wherein applying the coating composition in powder form to the substrate or portion thereof comprises applying the coating composition to a side seam of a container.

12 . The method of claim 1 , wherein providing a substrate comprises forming the substrate into a side seam of a container.

13 . The method of claim 1 , wherein the average coating thickness ranges from about 40 micrometers to about 90 micrometers.

14 . The method of claim 1 , wherein the formed coating is substantially free of pores.

15 . A coating composition comprising:
from about 50% by weight to 99% by weight of at least one polyester resin having a weight-average molecular weight ranging from about 20,000 to about 50,000; and from about 1% to 5% by weight of a resin component having a weight-average molecular weight ranging from about 3000 to about 10,000, wherein the coating composition is in the form of a powder having particles with particle sizes such that at least about 99% by weight of the particles are capable of passing through a 100-micrometer sieve; wherein the coating composition is configured to form a coating having an average coating thickness less than about 70 micrometers; and wherein the coating composition demonstrates optimal adhesion when applied and melted to form a coating on at least one portion of a substrate formed into a side seam of a container.

16 . A container comprising:
a substrate; and a coating disposed on at least a portion of the substrate with an average coating thickness less than about 70 micrometers, wherein the coating is substantially free of pores, and is formed from a coating composition comprising:
from about 50% by weight to 99% by weight of at least one polyester resin having a weight-average molecular weight ranging from about 20,000 to about 50,000; and
from about 15 to about 5% of a resin component having a weight-average molecular weight ranging from about 3000 to about 10,000,
wherein the coating composition prior to being formed on the substrate, is in the form of a powder having particles with particle sizes such that at least about 99% by weight of the particles are capable of passing through an 100-micrometer sieve, and wherein the coating demonstrates optimal adhesion when applied and melted to form a coating on at least one portion of a substrate formed into a side seam of a container.

17 . The container of claim 15 , wherein the substrate comprises a side seam of the container, and the coating is a side seam coating.

18 . The container of claim 15 , wherein the coating composition is substantially bisphenol-free.

19 . The container of claim 15 , wherein the resin component is a copolymer including a first monomeric unit derived from a glycidyl ester of an α,β-unsaturated acid or anhydride thereof, and a second monomeric unit having the structure:

wherein R 1 is —H or —CH 3 , and R 2 is a C1-C16 alkyl group.

20 . The container of claim 15 , wherein the resin component is a polymer derived from glycidyl methacrylate.

Assignees

• Valspar Sourcing Inc

Inventors

• Martinoni Raffaele
• Frischkopf Rolf

Classifications

• B65D25/14

  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 title

• C09D167/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds (C09D167/06 takes precedence) · CPC title

• C08F120/32

  containing epoxy radicals · CPC title

• C09D167/00

  Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain (based on polyester-amides C09D177/12; based on polyester-imides C09D179/08); Coating compositions based on derivatives of such polymers · CPC title

• C09D5/03 Primary

  Powdery paints · CPC title