Patent ID: 7097705

Claim:
In a method for applying a coating of a water-based composition to a surface to partially or fully coat the surface, the composition containing an inorganic or organic compound and an effective amount of a surfactant for reducing the dynamic surface tension of the composition, the improvement which comprises employing as the surfactant a mixture of an anionic surfactant and a weak base cationic surfactant having a pK a less than 11.5 and being an amine surfactant selected from the group consisting of R 1 R 2 N—R 3 , R 1 R 2 N—R′ 1 —NR 3 R 4 where R 1 is C4–18 alkyl, hydroxyalkyl, alkoxyalkyl or hydroxyalkoxyalkyl, and each of R 2 , R 3 , and R 4 is independently H, C1–10 alkyl, C1–10 hydroxyalkyl, C1–10 hydroxy-alkoxyalkyl, benzyl or —(C 2 H 4 O) n H where n has a value from 1 to 14, and not more than one of R 2 , R 3 , and R 4 is benzyl, and R′ 1 is a linking chain of 2–6 carbons, 2–6 carbons and an ether oxygen, or is two linking chains, such that N—R′ 1 —N is a piperazine ring; R 1 R 2 N—R′ 1 —(NR 5 —R′ 2 ) r —NR 3 R 4 where R 1 is C4–18 alkyl, hydroxyalkyl, alkoxyalkyl or hydroxyalkoxyalkyl, and each of R 2 , R 3 , and R 4 is independently H, C1–10 alkyl, C1–10 hydroxyalkyl, C1–10 hydroxy-alkoxyalkyl, benzyl or —(C 2 H 4 O) n H where n has a value from 1 to 14, and not more than one of R 2 , R 3 , and R 4 is benzyl, and R′ 1 is a linking chain of 2–6 carbons, 2–6 carbons and an ether oxygen, or is two linking chains, such that N—R′ 1 —N is a piperazine ring, R′ 2 is a C2–3 chain, r is 1–2 and R 5 is H, C1–10 alkyl, C1–10 hydroxyalkyl, C1–10 hydroxyalkoxyalkyl, benzyl or —(C 2 H 4 O) n H where n has a value from 1 to 14, and not more than one of R 2 , R 3 , R 4 and R 5 is benzyl; and R 6 —HN(CH 2 ) 2 [O(CH 2 ) n ] m O(CH 2 ) q NH—R 7 where n is 2–6, m is 0–4, and q is 2–6, and R 6 and R 7 independently are an alkyl group comprising 5 to 18 carbons; where the ratio of carbon atoms to nitrogen plus ether and hydroxy oxygen atoms (C:N+O) in the weak base cationic surfactant is 2.5:1 to 10:1, an amount in moles of the mixture demonstrating a dynamic surface tension (DST) which is less than the DST of the same amount in moles of the individual anionic and weak base cationic surfactants, and less than 45 dynes/cm at a concentration of ≦5 wt % in water at 23° C. and 20 bubbles/second or less than 40 dynes/cm at a concentration of ≦0.03M in water at 23° C. and 0.1 bubbles/second according to the maximum-bubble pressure method.