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.

An object of the present disclosure is to provide a coating composition containing a dissolved, specific fluoropolymer at a high concentration that is usable in fluoropolymer coating. The present disclosure relates to a coating composition containing a fluoropolymer and an aprotic solvent, and the fluoropolymer contains, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group; and the concentration of the fluoropolymer is 20 mass % or more based on the total mass of the coating composition.

An object of the present disclosure is to provide a laminate comprising a fluoropolymer layer with insulating properties, hardness, or transparency. The present disclosure relates to a laminate comprising a fluoropolymer layer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

An object of the present disclosure is to provide an insulating film or dielectric film comprising a fluoropolymer and having electrical insulation and hardness. The present disclosure relates to an insulating film or dielectric film comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein
R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

The present invention pertains to: a fluororesin that includes a residue unit represented by formula (1), and a terminal group represented by formula (2); and a fluororesin that includes a residue unit represented by formula (1) and has a transmittance of 50% or more measured at an optical path length of 10 mm and a wavelength of 275 nm when dissolved in perfluorohexane to produce a 10 wt % perfluorohexane solution.

##STR00001##

In formula (1): Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 each independently represent one selected from the group consisting of fluorine atoms, C1-7 linear perfluoroalkyl groups, C3-7 branched perfluoroalkyl groups, or C3-7 cyclic perfluoroalkyl groups; the perfluoroalkyl groups may have an etheric oxygen atom; Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may bond to each other to form a ring having 4 to 8 carbon atoms; and the ring may include an etheric oxygen atom.

##STR00002##

In formula (2), i is an integer of 3-20. The present invention provides: a fluororesin that includes an oxolane ring, has suppressed yellowing after heating and melting, and especially has reduced discoloration, even in molding of thick products; and a method for producing said fluororesin.

The present invention provides a method for manufacturing an optical resin composition that is less colored and that has a sufficiently low water absorbability. The optical resin composition manufacturing method according to the present invention includes performing a heat treatment of a fluorine-containing polymer under an atmosphere having a water vapor concentration of 100 volppm or less, the fluorine-containing polymer being obtained by polymerization of a monomer group including a fluorine-containing compound having a carbon-carbon double bond using an organic peroxide. In the optical resin composition manufacturing method, for example, the heat treatment causes thermal decomposition of a terminal group of the fluorine-containing polymer and volatilization of a low-molecular compound generated by the thermal decomposition.

The present invention provides a method for manufacturing an optical resin composition that is less colored and that has a sufficiently low water absorbability. The optical resin composition manufacturing method according to the present invention includes performing a heat treatment of a fluorine-containing polymer under an atmosphere having a water vapor concentration of 100 volppm or less, the fluorine-containing polymer being obtained by polymerization of a monomer group including a fluorine-containing compound having a carbon-carbon double bond using an organic peroxide. In the optical resin composition manufacturing method, for example, the heat treatment causes thermal decomposition of a terminal group of the fluorine-containing polymer and volatilization of a low-molecular compound generated by the thermal decomposition.