Absorbent sheet is manufactured utilizing a low charge density debonder composition comprising an imidazolinium surfactant-containing constituent selected from the group consisting of: (i) cationic imidazolinium surfactants with alkylalkenylhydroxy substitution; (ii) zwitterionic imidazolinium surfactants; and (iii) an ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant and, in admixture with the imidazolinium surfactant-containing constituent, (iv) a nonionic surfactant.

Absorbent sheet is manufactured utilizing a low charge density debonder composition comprising an imidazolinium surfactant-containing constituent selected from the group consisting of: (i) cationic imidazolinium surfactants with alkylalkenylhydroxy substitution; (ii) zwitterionic imidazolinium surfactants; and (iii) an ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant and, in admixture with the imidazolinium surfactant-containing constituent, (iv) a nonionic surfactant.

Absorbent sheet is manufactured utilizing a low charge density debonder composition comprising an imidazolinium surfactant-containing constituent selected from the group consisting of: (i) cationic imidazolinium surfactants with alkylalkenylhydroxy substitution; (ii) zwitterionic imidazolinium surfactants; and (iii) an ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant and, in admixture with the imidazolinium surfactant-containing constituent, (iv) a nonionic surfactant.

Absorbent sheet is manufactured utilizing a low charge density debonder composition comprising an imidazolinium surfactant-containing constituent selected from the group consisting of: (i) cationic imidazolinium surfactants with alkylalkenylhydroxy substitution; (ii) zwitterionic imidazolinium surfactants; and (iii) an ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant and, in admixture with the imidazolinium surfactant-containing constituent, (iv) a nonionic surfactant.

An on-line control and reaction process for pH adjustment and a control device for automatically adjusting pH value are provided. The process includes mixing a first enhancer and a second enhancer, optionally after diluting the first enhancer and/or the second enhancer with water, to form a mixture, setting a base pH value (1) and a target pH value (2), and adding pH adjuster into the mixture via a pH control unit and mixing to obtain a product with the target pH value. The pH control unit adjusts the adding of the pH adjuster by measuring or inputting certain parameters.

An on-line control and reaction process for pH adjustment and a control device for automatically adjusting pH value are provided. The process includes mixing a first enhancer and a second enhancer, optionally after diluting the first enhancer and/or the second enhancer with water, to form a mixture, setting a base pH value (1) and a target pH value (2), and adding pH adjuster into the mixture via a pH control unit and mixing to obtain a product with the target pH value. The pH control unit adjusts the adding of the pH adjuster by measuring or inputting certain parameters.

Provided are a paper strengthener coating device, a sheet manufacturing apparatus, a sheet, and a paper strengthener coating method capable of suppressing production of paper dust from sheets when printing on sheets of paper. The paper strengthener coating device has: a solution supply device configured to supply a solution containing a paper strengthener; an inkjet head having nozzles for ejecting the solution supplied from the solution supply device; and a paper strengthener coating unit configured to apply the solution ejected from the nozzles onto a sheet; the inkjet head preferentially or selectively applying the solution to an edge part of the sheet.

Zwitterionic surfactant compounds and their use in connection with absorbent paper manufacture in debonder and softener formulations. An exemplary surfactant is an imidazolinium compound of formula:

##STR00001##

wherein X is SO.sub.3, R.sup.1 is a hydrocarbyl spacer group having a chain length of from 2-6 carbon atoms, R.sup.2 is a hydrocarbyl group having from 8 to 22 carbon atoms; and R.sup.3 is an alkenylamidoalkyl moiety having from 8 to 30 carbon atoms.

Zwitterionic surfactant compounds and their use in connection with absorbent paper manufacture in debonder and softener formulations. An exemplary surfactant is an imidazolinium compound of formula:

##STR00001##

wherein X is SO.sub.3, R.sup.1 is a hydrocarbyl spacer group having a chain length of from 2-6 carbon atoms, R.sup.2 is a hydrocarbyl group having from 8 to 22 carbon atoms; and R.sup.3 is an alkenylamidoalkyl moiety having from 8 to 30 carbon atoms.

Absorbent sheet is manufactured utilizing a low charge density debonder composition comprising an imidazolinium surfactant-containing constituent selected from the group consisting of: (i) cationic imidazolinium surfactants with alkylalkenylhydroxy substitution; (ii) zwitterionic imidazolinium surfactants; and (iii) an ion paired surfactant mixture including a zwitterionic imidazolinium surfactant and a cationic surfactant and, in admixture with the imidazolinium surfactant-containing constituent, (iv) a nonionic surfactant.