Sulfonate-functional coating compositions, methods of making the same, and articles therefrom

1 . A coating composition consisting of

(a) a zwitterionic compound comprising (i) sulfonate-functional groups and (ii) alkoxysilane groups and/or silanol-functional groups;

(b) an acid-catalyzed hydrolysis product of an alkoxysilane and a weak acid, wherein the acid-catalyzed hydrolysis product of an alkoxysilane comprises at least one (i)(RO) (4-a) Si(OH) a where R is a monovalent hydrocarbon group and a is an integer from 1 to 4; or (ii) an alkanol silicate acid oligomer;

(c) a water-miscible organic solvent;

(d) water, and optionally a surfactant.

2 . The coating composition of claim 1 , wherein the zwitterionic compound is of Formula (I) (R 1 O) p —Si(Q 1 ) q -X—N + (Y 1 Y 2 )—(Z)—SO 3 − (I)

Wherein each R 1 is independently a hydrogen, methyl group, or ethyl group;

each Q 1 is independently selected from hydroxyl, alkyl groups containing from 1 to 4 carbon atoms and alkoxy groups containing from 1 to 4 carbon atoms;

p is 1, 2, or 3;

q is 0, 1, or 2;

p+q=3;

X is a divalent alkylene group comprising at least 2, and no more than 12 carbon atoms and optionally comprising at least one ether linkage, at least one carbamate linkage, and/or at least one urea linkage;

Y 1 and Y 2 are each independently a monovalent alkyl group; and

Z is a divalent alkylene group comprising at least 2 and no more than 12 carbon atoms and optionally comprising a pendent hydroxyl group.

3 . The coating composition of claim 1 , wherein the zwitterionic compound is of Formula (III)

(R 1 O) p —Si(Q 1 ) q -CH 2 CH 2 CH 2 —N + (CH 3 ) 2 —(CH 2 ) m —SO 3 −   (III)

wherein:

each R 1 is independently a hydrogen, methyl group, or ethyl group;

each Q 1 is independently selected from hydroxyl, alkyl groups containing from 1 to 4 carbon atoms and alkoxy groups containing from 1 to 4 carbon atoms;

p and m are integers of 1 to 4;

q is 0 or 1; and

p+q=3.

4 . The coating composition of claim 1 , wherein the zwitterionic compound is of Formula (II)

(R 1 O) p —Si(Q 1 ) q -(X) r -(pyradinyl)-(Z)—SO 3 −   (II)

Wherein each R 1 is independently a hydrogen, methyl group, or ethyl group;

each Q 1 is independently selected from hydroxyl, alkyl groups containing from 1 to 4 carbon atoms and alkoxy groups containing from 1 to 4 carbon atoms;

p is 1, 2, or 3;

q is 0, 1, or 2;

p+q=3;

r is 0 or 1;

X is a divalent alkylene group comprising at least 2, and no more than 12 carbon atoms and optionally comprising at least one ether linkage, at least one carbamate linkage, and/or at least one urea linkage;

pyridinyl is a divalent pyridine group; and

Z is a divalent alkylene group comprising at least 2 and no more than 12 carbon atoms and optionally comprising a pendent hydroxyl group.

5 . The coating composition of claim 1 , wherein the zwitterionic compound is selected from at least one of:

(CH 3 O) 3 Si—CH 2 CH 2 CH 2 —N + (CH 3 ) 2 —CH 2 CH 2 CH 2 —SO 3 −

(CH 3 CH 2 O) 2 Si(CH 3 )—CH 2 CH 2 —N + (CH 3 ) 2 —CH 2 CH 2 CH 2 —SO 3 −

6 . The coating composition of claim 1 , wherein the acid-catalyzed hydrolysis product of an alkoxysilane comprises (RO) (4-a) Si(OH) a and R is a monovalent hydrocarbon group comprising 1 or 2 carbon atoms and a is an integer from 1 to 4.

7 . The coating composition of claim 1 , wherein the acid-catalyzed hydrolysis product of an alkoxysilane comprises the alkanol silicate acid oligomer and wherein the alkanol silicate acid oligomer comprises a C1 to C2 alkanol.

8 . The coating composition of claim 1 , wherein the acid-catalyzed hydrolysis product of an alkoxysilane comprises the alkanol silicate acid oligomer and wherein the alkanolsilicate acid oligomer has a molecular weight of less than 1,000 daltons.

9 . The coating composition of claim 1 , wherein the surfactant is selected from an alkyl sulfate, alkyl ether sulfate, alkyl ethoxylate, and combinations thereof.

10 . An article comprising a substrate with a coating layer thereon, wherein the coating layer is preparable by combining the components consisting of: (a) a zwitterionic compound comprising (i) sulfonate-functional groups and (ii) alkoxysilane groups and/or silanol-functional groups; (b) an acid-catalyzed hydrolysis product of an alkoxysilane, wherein the acid-catalyzed hydrolysis product of an alkoxysilane is derived from an alkoxysilane and a weak acid and wherein the acid-catalyzed hydrolysis product of an alkoxysilane comprises at least one (i) (RO) (4-a) Si(OH) a where R is a monovalent hydrocarbon group and a is an integer from 1 to 4; or (ii) an alkanol silicate acid oligomer; (c) a water-miscible organic solvent; and (d) water.

11 . The article of claim 10 , wherein the substrate is at least one of a corona-treated polyethylene terephtalate and nano-silica coated polyethylene terephtalate.

12 . A method comprising:

contacting a coating composition consisting of (a) an acid-catalyzed hydrolysis product of an alkoxysilane with (b) a zwitterionic compound, wherein the zwitterionic compound comprises (i) sulfonate-functional groups and (ii) alkoxysilane groups and/or silanol-functional groups; (c) a water-miscible organic solvent; and (d) water to form a coating composition, wherein the acid-catalyzed hydrolysis product of an alkoxysilane is derived from an alkoxysilane and a weak acid.

13 . The coating composition of claim 1 , wherein the coating composition consists of at least 0.1 wt % of the zwitterionic compound.

14 . The coating composition of claim 1 , wherein the weak acid has a pKa of at least 3.0 as measured in water in ambient conditions.

15 . The article of claim 10 , wherein the coating layer has a thickness of at least 2 micrometers.