The present application provides a lithium-ion secondary battery, comprising an aldehyde-ketone polymer. The aldehyde-ketone polymer satisfies: 5m/n1000, in which n represents a mass of the aldehyde-ketone polymer, in grams, and m represents a mass, in grams, of a first substance that is obtained by: adding the aldehyde-ketone polymer to a first solvent at 45 C. to form a polymer system; allowing the polymer system to stand for 8 hours at 45 C. and for 24 hours at 25 C., and then filtering the polymer system through a 200-mesh screen to obtain remains as the first substance.

The present application provides a lithium-ion secondary battery, comprising an aldehyde-ketone polymer. The aldehyde-ketone polymer satisfies: 5m/n1000, in which n represents a mass of the aldehyde-ketone polymer, in grams, and m represents a mass, in grams, of a first substance that is obtained by: adding the aldehyde-ketone polymer to a first solvent at 45 C. to form a polymer system; allowing the polymer system to stand for 8 hours at 45 C. and for 24 hours at 25 C., and then filtering the polymer system through a 200-mesh screen to obtain remains as the first substance.

The present invention relates to resin particles including a residue unit represented by the following general formula (1) and having a volume average particle diameter equal to or more than 5 m and equal to or less than 2008 m, and a method for producing thereof. Fruthermore the present invention relates to a fluororesin comprising a residue unit represented by a general formula (1) and having a weight average molecular weight Mw in a range of 510.sup.4 to 310.sup.5, and a yellow index of a heat-melted molded product (thickness 3 mm) after 24 h at 280 C. of equal to or less than 6, and a method for producing thereof. ##STR00001##
In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 are each independently one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, or a cyclic perfluoroalkyl group having 3 to 7 carbon atoms. The perfluoroalkyl group may have an ethereal oxygen atom. Further, Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may be linked to one another to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.

The present invention relates to resin particles including a residue unit represented by the following general formula (1) and having a volume average particle diameter equal to or more than 5 m and equal to or less than 2008 m, and a method for producing thereof. Fruthermore the present invention relates to a fluororesin comprising a residue unit represented by a general formula (1) and having a weight average molecular weight Mw in a range of 510.sup.4 to 310.sup.5, and a yellow index of a heat-melted molded product (thickness 3 mm) after 24 h at 280 C. of equal to or less than 6, and a method for producing thereof. ##STR00001##
In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 are each independently one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, or a cyclic perfluoroalkyl group having 3 to 7 carbon atoms. The perfluoroalkyl group may have an ethereal oxygen atom. Further, Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may be linked to one another to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.