Manufacture of absorbent paper with low charge density imidazolinium containing debonder compositions

1. An ion paired surfactant mixture useful for debonder and softener compositions utilized in absorbent paper manufacture, said mixture comprising a zwitterionic imidazolinium surfactant and a cationic imidazolinium surfactant, said zwitterionic imidazolinium surfactant having the structural formula I:

wherein:

R 5 is a straight or branched hydrocarbon spacer moiety having from 2-18 carbon atoms wherein said R 5 may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —C(═O)(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)O(C 1 -C 6 )alkyl, N[(C 1 -C 6 )alkyl] 2 , and —NH[(C 1 -C 6 )alkyl] and/or may have interposed within said hydrocarbon spacer moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

R 6 is a straight or branched saturated or unsaturated hydrocarbon moiety having from 3 to 30 carbon atoms wherein said R 6 :

(i) may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)(C 1 -C 6 )alkyl, —C(═O)O(C 1 -C 6 )alkyl, —N[(C 1 -C 6 )alkyl] 2 , —NH—C(O)(C 1 -C 6 )alkyl, —C(O)NH 2 , —C(O)—NH(C 1 -C 6 )alkyl, and —NH(C 1 -C 6 )alkyl, and/or

(ii) may have interposed within said hydrocarbon moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

R 7 is a straight or branched saturated or unsaturated hydrocarbon moiety having from 3 to 30 carbon atoms wherein said R 7 :

(i) may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)(C 1 -C 6 )alkyl, —C(═O)O(C 1 -C 6 )alkyl, —N[(C 1 -C 6 )alkyl] 2 , —NH—C(O)(C 1 -C 6 )alkyl, —C(O)NH 2 , —C(O)—NH(C 1 -C 6 )alkyl, and —NH(C 1 -C 6 )alkyl, and/or

(ii) may have interposed within said hydrocarbon moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

wherein at least one of R 6 or R 7 has from 8 to 30 carbon atoms;

X is selected from the group consisting of SO 3 , CO 2 , PO 3 and HPO 2 ; and

p is 1 or 2 and

wherein the cationic imidazolinium surfactant has the structural formula:

wherein:

R 9 is H, methyl, ethyl, or propyl;

R 10 is an alkylalkenyl moiety having from 11 to 21 carbon atoms;

R 11 is an ethylene or propylene bridging group;

R 12 is an amidoalkenylalkyl moiety having from 12 to 22 carbon atoms;

p is 1 or 2; and

X is selected from halides, sulfates, carboxylates and phosphates.

2. The ion paired surfactant mixture useful for debonder and softener compositions utilized in absorbent paper manufacture according to claim 1 , wherein R 10 is a hydroxy substituted alkylalkenyl moiety having from 11 to 21 carbon atoms and R 12 is an amidoalkenylalkyl moiety bearing a pendant hydroxyl group having from 12 to 22 carbon atoms.

3. The ion paired surfactant mixture according to claim 1 , wherein the molar ratio of cationic imidazolinium surfactant to zwitterionic surfactant is from 55:45 to 80:20.

4. The ion paired surfactant mixture according to claim 3 , wherein the molar ratio of cationic imidazolinium surfactant to zwitterionic surfactant is from 60:40 to 75:25.

5. A debonder composition for absorbent paper manufacture comprising the ion paired surfactant mixture of claim 1 in admixture with a nonionic surfactant.

6. The debonder composition according to claim 5 , wherein the debonder composition comprises from 5 to 45 wt. % of the ion paired surfactant mixture and from 65 to 95 wt. percent of nonionic surfactant.

7. The debonder composition according to claim 5 , wherein the debonder composition comprises a nonionic surfactant selected from alkoxylated fatty acids and alkoxylated fatty alcohols.

8. The debonder composition according to claim 5 , wherein the debonder composition exhibits a charge density of from 0.15 to 0.25 meq/g.

9. The debonder composition according to claim 1 , wherein in formula I, R 5 is a straight or branched hydrocarbon spacer moiety having from 2-18 carbon atoms and the X substituent on the zwitterionic surfactant formula I is SO 3 .

10. A debonder composition comprising a nonionic surfactant in admixture with an ion paired surfactant mixture, said ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant selected from cationic imidazolinium surfactants and quaternary ammonium surfactants, said zwitterionic imidazolinium surfactant having the structural formula I:

wherein:

R 5 is a straight or branched hydrocarbon spacer moiety having from 2-18 carbon atoms wherein said R 5 may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —C(═O)(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)O(C 1 -C 6 )alkyl, N[(C 1 -C 6 )alkyl] 2 , and —NH[(C 1 -C 6 )alkyl] and/or may have interposed within said hydrocarbon spacer moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

R 6 is a straight or branched saturated or unsaturated hydrocarbon moiety having from 3 to 30 carbon atoms wherein said R 6 :

(i) may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)(C 1 -C 6 )alkyl, —C(═O)O(C 1 -C 6 )alkyl, —N[(C 1 -C 6 )alkyl] 2 , —NH—C(O)(C 1 -C 6 )alkyl, —C(O)NH 2 , —C(O)—NH(C 1 -C 6 )alkyl, and —NH(C 1 -C 6 )alkyl, and/or

(ii) may have interposed within said hydrocarbon moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

R 7 is a straight or branched saturated or unsaturated hydrocarbon moiety having from 3 to 30 carbon atoms wherein said R 7 :

(i) may be unsubstituted or optionally substituted with one or more groups which can be the same or different and are independently selected from the group consisting of halogen, cyano, alkyl, cycloalkyl, —OH, O(C 1 -C 6 )alkyl, —CO 2 H, —C(═O)(C 1 -C 6 )alkyl, —C(═O)O(C 1 -C 6 )alkyl, —N[(C 1 -C 6 )alkyl] 2 , —NH—C(O)(C 1 -C 6 )alkyl, —C(O)NH 2 , —C(O)—NH(C 1 -C 6 )alkyl, and —NH(C 1 -C 6 )alkyl, and/or

(ii) may have interposed within said hydrocarbon moiety one or more groups which may be the same or different and are independently selected from the group consisting of —NH—C(O)—, —C(O)—NH—, —O—, —SO 2 — and —C(═O)—;

wherein at least one of R 6 or R 7 has from 8 to 30 carbon atoms;

X is selected from the group consisting of SO 3 , CO 2 , PO 3 and HPO 2 ; and

p is 1 or 2,

wherein the cationic imidazolinium surfactant has the structural formula:

wherein:

R 9 is H, methyl, ethyl, or propyl;

R 10 is an alkylalkenyl moiety having from 11 to 21 carbon atoms;

R 11 is an ethylene or propylene bridging group;

R 12 is an amidoalkenylalkyl moiety having from 12 to 22 carbon atoms;

p is 1 or 2; and

X is selected from halides, sulfates, carboxylates and phosphates,

Wherein the quaternary ammonium surfactant is selected from the group consisting of:

a dialkyldimethylammonium compound of the formula:

and

a bis-dialkylamidoammonium compound of the formula:

wherein each R may be the same or different and each R indicates a hydrocarbon chain, saturated or unsaturated, having a chain length of from about twelve to about twenty-two carbon atoms; and wherein said compounds are supplied to the surfactant mixture with a suitable anion; and

wherein the debonder composition exhibits a charge density of less than 0.3 meq/g.