The present invention provides a polyvinyl acetal resin which leaves less fine undissolved matter when dissolved in an organic solvent and thus can improve productivity particularly when used as a binder for a ceramic green sheet, and which can also provide a ceramic green sheet having excellent toughness and enables production of a highly reliable multilayer ceramic capacitor. Provided is a polyvinyl acetal resin having: a wavenumber A (cm.sup.−1) of a peak within a range of 3,100 to 3,700 cm.sup.−1 in an IR absorption spectrum measured using an infrared spectrophotometer; and a hydroxy group content (mol %), the wavenumber A of the peak and the hydroxy group content satisfying relations of the following formulas (1) and (2):

[(3,470−A)/Hydroxy group content]≤5.5  (1)

(3,470−A)≤185  (2)

wherein A is a wavenumber which is lower than 3,470 cm.sup.−1 and at which a transmittance a (%) satisfying [100−(100−X)/2] is exhibited, where X (%) is a minimum transmittance of the peak within the wavenumber range of 3,100 to 3,700 cm.sup.−1.

The present invention provides a polyvinyl acetal resin which leaves less fine undissolved matter when dissolved in an organic solvent and thus can improve productivity particularly when used as a binder for a ceramic green sheet, and which can also provide a ceramic green sheet having excellent toughness and enables production of a highly reliable multilayer ceramic capacitor. Provided is a polyvinyl acetal resin having: a wavenumber A (cm.sup.−1) of a peak within a range of 3,100 to 3,700 cm.sup.−1 in an IR absorption spectrum measured using an infrared spectrophotometer; and a hydroxy group content (mol %), the wavenumber A of the peak and the hydroxy group content satisfying relations of the following formulas (1) and (2):

[(3,470−A)/Hydroxy group content]≤5.5  (1)

(3,470−A)≤185  (2)

wherein A is a wavenumber which is lower than 3,470 cm.sup.−1 and at which a transmittance a (%) satisfying [100−(100−X)/2] is exhibited, where X (%) is a minimum transmittance of the peak within the wavenumber range of 3,100 to 3,700 cm.sup.−1.

A poly(vinyl acetal) composition, such as a poly(vinyl butyral) composition or resin, can be made containing recycle content by the use of a recycle content aldehyde composition as a feedstock to make the PVA or by application of a recycle allotment, such as an allocation or credit, applied to either the aldehyde composition or to the PVA composition. The recycle content is obtained by cracking a recycle content pyrolysis oil to make a variety of olefins, such as propylene or ethylene.

A poly(vinyl acetal) composition, such as a poly(vinyl butyral) composition or resin, can be made containing recycle content by the use of a recycle content aldehyde composition as a feedstock to make the PVA or by application of a recycle allotment, such as an allocation or credit, applied to either the aldehyde composition or to the PVA composition. The recycle content is obtained by cracking a recycle content pyrolysis oil to make a variety of olefins, such as propylene or ethylene.

A hydrophilic polymer comprising pendent groups of the formula I: Wherein: W is independently selected from —OH, —COOH, —SO.sub.3H, —OPO.sub.3H, —O—(C.sub.1-4alkyl), —O—(C.sub.1-4alkyl)OH, —O—(C.sub.1-4alkyl)R.sup.2, —O—(C.sub.2H.sub.5O).sub.qR.sup.1—(C═O)—O—C.sub.1-4alkyl and —O—(C═O)C.sub.1-4alkyl; or a group —BZ; wherein —OH, COOH, O—PO.sub.3H and SO.sub.3H maybe in the form of a pharmaceutically acceptable salt; wherein: B is a bond, or a straight branched alkanediyl, oxyalkylene, alkylene oxaalkylene, or alkylene (oligooxalkylene) group, optionally containing one or more fluorine substituents; and Z is an ammonium, phosphonium, or sulphonium phosphate or phosphonate ester zwitterionic group; X is either a bond or a linking group having 1 to 8 carbons and optionally 1 to 4 heteroatoms selected from O, N and S; G is a coupling group through which the group of the formula I is coupled to the polymer and is selected from ether, ester, amide, carbonate, carbamate, 1,3 dioxolone, and 1,3 dioxane; R.sup.1 is H or C.sub.1-4 alkyl; R.sup.2 is —COOH, —SO.sub.3H, or —OPO.sub.3H.sub.2 q is an integer from 1 to 4; n is an integer from 1 to 4; p is an integer from 1 to 3; and n+p is from 2 to 5; and wherein —COOH, —OPO.sub.3H.sub.2 and —SO.sub.3H as well as phenolic —OH maybe in the form of a pharmaceutically acceptable salt.

A hydrophilic polymer comprising pendent groups of the formula I: Wherein: W is independently selected from —OH, —COOH, —SO.sub.3H, —OPO.sub.3H, —O—(C.sub.1-4alkyl), —O—(C.sub.1-4alkyl)OH, —O—(C.sub.1-4alkyl)R.sup.2, —O—(C.sub.2H.sub.5O).sub.qR.sup.1—(C═O)—O—C.sub.1-4alkyl and —O—(C═O)C.sub.1-4alkyl; or a group —BZ; wherein —OH, COOH, O—PO.sub.3H and SO.sub.3H maybe in the form of a pharmaceutically acceptable salt; wherein: B is a bond, or a straight branched alkanediyl, oxyalkylene, alkylene oxaalkylene, or alkylene (oligooxalkylene) group, optionally containing one or more fluorine substituents; and Z is an ammonium, phosphonium, or sulphonium phosphate or phosphonate ester zwitterionic group; X is either a bond or a linking group having 1 to 8 carbons and optionally 1 to 4 heteroatoms selected from O, N and S; G is a coupling group through which the group of the formula I is coupled to the polymer and is selected from ether, ester, amide, carbonate, carbamate, 1,3 dioxolone, and 1,3 dioxane; R.sup.1 is H or C.sub.1-4 alkyl; R.sup.2 is —COOH, —SO.sub.3H, or —OPO.sub.3H.sub.2 q is an integer from 1 to 4; n is an integer from 1 to 4; p is an integer from 1 to 3; and n+p is from 2 to 5; and wherein —COOH, —OPO.sub.3H.sub.2 and —SO.sub.3H as well as phenolic —OH maybe in the form of a pharmaceutically acceptable salt.

Equipment for preparing a polymer solution of a non-ionic, cationic, anionic or amphoteric polymer by reaction between a compound including at least one aldehyde function and at least one base polymer aqueous solution having at least one non-ionic monomer includes a reactor provided with a stirring system, as well as a recirculation loop including between the outlet of the reactor and the inlet of the reactor, a recirculation pump, a pH measuring probe, and a pressure differential in-line measuring device in the form of a calibrated tube configured to measure the pressure difference of the polymer solution between the inlet and the outlet of the calibrated tube, the calibrated tube being branched on the recirculation loop.

Equipment for preparing a polymer solution of a non-ionic, cationic, anionic or amphoteric polymer by reaction between a compound including at least one aldehyde function and at least one base polymer aqueous solution having at least one non-ionic monomer includes a reactor provided with a stirring system, as well as a recirculation loop including between the outlet of the reactor and the inlet of the reactor, a recirculation pump, a pH measuring probe, and a pressure differential in-line measuring device in the form of a calibrated tube configured to measure the pressure difference of the polymer solution between the inlet and the outlet of the calibrated tube, the calibrated tube being branched on the recirculation loop.

Equipment for preparing a polymer solution of a non-ionic, cationic, anionic or amphoteric polymer by reaction between a compound including at least one aldehyde function and at least one base polymer aqueous solution having at least one non-ionic monomer includes a reactor provided with a stirring system, as well as a recirculation loop including between the outlet of the reactor and the inlet of the reactor, a recirculation pump, a pH measuring probe, and a pressure differential in-line measuring device in the form of a calibrated tube configured to measure the pressure difference of the polymer solution between the inlet and the outlet of the calibrated tube, the calibrated tube being branched on the recirculation loop.

A water-absorbent copolymer may include a vinyl alcohol constituent unit x and a constituent unit z other than the vinyl alcohol constituent unit x and a vinyl ester constituent unit y, wherein a ratio of a content of an average sequence of the constituent unit z to a content of the constituent unit z is 50.0 mol % or less.