Method to increase resistance against stain penetration of aqueous coating compositions

• US 8,901,237 B2
• Filed: 09/11/2006
• Issued: 12/02/2014
• Est. Priority Date: 09/12/2005
• Status: Active Grant

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Chowdhry, Mubarik Mahmood, Yamashita, Hideki, Yong, Cheeseng, Allen, Jonathon Shane, Redfern, David, Schuler, Bernhard, Wagner, Oliver, Catterall, Gregory John, Van Sonsbeek, Roger Jan, Christie, David
• Primary Examiner(s): Wu, David W
• Assistant Examiner(s): REDDICK, MARIE L
• Application Number:
  US12/066,155
• Publication Number:
  US 20080245259A1
• Time in Patent Office: 3,004 Days
• Field of Search: 524/140, 524/156, 524/556, 524/560, 524/555, 524/558, 524/561, 524/562, 427/385.5
• US Class Current: 524/556
• CPC Class Codes: C08K 5/41 Compounds containing sulfur bound to oxygen
• CPC Class Codes: C08K 5/521 Esters of phosphoric acids, e.g. of H3PO4
• CPC Class Codes: C09D 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09D 133/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C09D 135/06 Copolymers with vinyl aromatic monomers
• CPC Class Codes: C09D 5/1625 organic
• CPC Class Codes: C09D 7/63 organic

Abstract

The invention also relates to a method to increase stain resistance and penetration resistance of aqueous coating compositions which method comprises providing a coating composition which contain at least one pigment, at least one film-forming polymer in the form of an aqueous polymer dispersion and at least one anionic surfactant, wherein the anionic surfactant comprises at least 85% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, based on the total weight of anionic surfactant in the coating composition, of at least one anionic surfactant S, which is selected from semi-esters of sulfuric acid or phosphoric acid with an alcohol, which alcohol carries at least one alkyl radical having from 8 to 30 carbon atoms or an alkyl substituted phenyl radical wherein alkyl has from 4 to 30 carbon atoms and which alcohol may carry an oligo-C₂-C₃-alkylene-ether group provided that the number of repeating units in the oligo-C₂-C₃-alkylene-ether group is at most 15, or a salt thereof.

Claims

1. A method for making an aqueous coating composition, which confers stain and penetration resistance when applied to a substrate and dried and/or cured, comprising mixing together at least one pigment, at least one film-forming polymer in the form of an aqueous polymer dispersion, and at least one anionic surfactant of formula (Ia), to obtain the aqueous coating composition;

wherein said aqueous coating composition comprises;

at least one pigment, an aqueous polymer dispersion containing at least one film-forming polymer, and at least one anionic surfactant (S) of formula (Ia);

wherein the at least one film-forming polymer, in polymerized form, consists of;

(M1a) 40 to 59.4% by weight of methyl methacrylate or a mixture thereof with styrene,

(M1b) 40 to 55% by weight of at least one C₂-C₁₀ alkyl ester of acrylic acid,

(M2) 0.1 to 3% by weight of itaconic acid, acrylic acid, methacrylic acid, or a mixture thereof,

(M3a) 0.5 to 3% by weight of acrylamide, methacrylamide, hydroxyethyl acrylate, or a mixture thereof, and

(M3b) 0 to 2% by weight of N-(2-methacryloxyethyl) imidazolin-2-one,

provided that a total amount of (M1a), (M1b), (M2), (M3a), and (M3b) is 100% by weight and a total amount of (M2), (M3a), and (M3b) is from 0.7 to 5% by weight, based on the total amount of (M1a), (M1b), (M2), (M3a), and (M3b); and

wherein the at least one surfactant (S) is of formula (Ia);

M_3-n[O_4-nP—

(O-(Alk-O)_mR)_n] 

 

(Ia),

wherein

n is 1 or 2,

m is an integer from 0 to 15,

M is hydrogen, an alkali metal ion, or an ammonium ion,

Alk is C₂-C₃-alkylene, and

R is C₈-C₃₀ alkyl or C₄-C₃₀ alkylphenyl;

wherein a weight ratio of the at least one pigment to the at least one film-forming polymer ranges from 4;

1 to 1;

5; and

wherein the amount of the at least one surfactant (S) of formula (Ia) constitutes at least 85% of the total amount by weight of anionic surfactants in the aqueous coating composition.

2. The method of claim 1, further comprising:

applying the aqueous coating composition to a surface of a substrate to give a coated substrate; and

curing the coated substrate to form a cured coating on the substrate; and

wherein red wine that is left static on a cured coating produced from a 125 μ

m wet film thickness of the aqueous coating composition on a glass substrate after curing for 7 days at 23°

C. does not penetrate the cured coating to the substrate.

3. The method of claim 1, wherein the aqueous coating has a pigment volume concentration (pvc) of at least 20%.

4. The method of claim 1, wherein in the aqueous coating composition

M in formula (Ia) is different from hydrogen, and

the groups Alk-O comprise at least 50% by weight of groups of formula CH₂CH₂O based on a total weight of the groups Alk-O.

5. The method of claim 1, wherein in the aqueous coating composition R in formula (Ia) is C₁₄-C₂₄ alkyl.

6. A method for providing stain and penetration resistance to a substrate comprising applying an aqueous coating composition to said substrate and drying and/or curing the aqueous coating composition;

wherein said aqueous coating composition comprises;

at least one pigment, an aqueous polymer dispersion containing at least one film-forming polymer, and at least one anionic surfactant (S) of formula (Ia);

wherein the at least one film-forming polymer, in polymerized form, consists of;

(M1a) 40 to 59.4% by weight of methyl methacrylate or a mixture thereof with styrene,

(M1b) 40 to 55% by weight of at least one C₂-C₁₀ alkyl ester of acrylic acid

(M2) 0.1 to 3% by weight of itaconic acid, acrylic acid, methacrylic acid, or a mixture thereof,

(M3a) 0.5 to 3% by weight of acrylamide, methacrylamide, hydroxyethyl acrylate, or a mixture thereof, and

(M3b) 0 to 2% by weight of N-(2-methacryloxyethyl) imidazolin-2-one

provided that a total amount of (M1a), (M1b), (M2), (M3a), and (M3b) is 100% by weight and a total amount of (M2), (M3a), and (M3b) is from 0.7 to 5% by weight, based on the total amount of (M1a), (M1b), (M2), (M3a), and (M3b); and

wherein the at least one surfactant (S) is of formula (Ia);

M_3-n[O_4-nP—

(O-(Alk-O)_mR)_n] 

 

(Ia),

wherein

n is 1 or 2,

m is an integer from 0 to 15,

M is hydrogen, an alkali metal ion, or an ammonium ion,

Alk is C₂-C₃-alkylene, and

R is C₈-C₃₀ alkyl or C₄-C₃₀ alkylphenyl;

wherein a weight ratio of the at least one pigment to the at least one film-forming polymer ranges from 4;

1 to 1;

5; and

wherein the amount of the at least one surfactant (S) of formula (Ia) constitutes at least 85% of the total amount by weight of anionic surfactants in the aqueous coating composition.

7. The method of claim 6, wherein the aqueous coating composition has a pigment volume concentration (pvc) of at least 20%.

8. The method of claim 6, wherein in the aqueous coating composition

M in formula (Ia) is different from hydrogen, and

the groups Alk-O comprise at least 50% by weight of groups of formula CH₂CH₂O based on a total weight of the groups Alk-O.

9. The method of claim 6, wherein in the aqueous coating composition R in formula (Ia) is C₁₄-C₂₄ alkyl.