The present invention relates to a polymer electrolyte for a secondary battery and a lithium secondary battery including the same, and to a polymer electrolyte for a secondary battery, which includes unit A derived from a poly(ethylene oxide)-based polymer, and a lithium secondary battery including the same.

A BrnstedLowry acid initiator system for cationic polymerization of an ethylenically unsaturated monomer involves an initiator having a structure of Formula (I) in an anhydrous polymerization medium (I) where: M is tantalum (Ta), vanadium (V) or niobium (Ni); each R.sub.1 is independently H, OR.sub.6, F, Cl, Br, I or alkyl, where R.sub.6 is H or alkyl; R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are independently H, F, Cl Br, I, alkyl or aryl, or two or more of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on a same benzene ring form a bicyclic, tricyclic or tetracyclic moiety with the benzene ring, with the proviso that all of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on the same benzene ring are not H; L is absent or a molecule that coordinates to H.sup.+; and, x is 0 when L is absent, or x is 0.5 or more when L is present.

##STR00001##

A BrnstedLowry acid initiator system for cationic polymerization of an ethylenically unsaturated monomer involves an initiator having a structure of Formula (I) in an anhydrous polymerization medium (I) where: M is tantalum (Ta), vanadium (V) or niobium (Ni); each R.sub.1 is independently H, OR.sub.6, F, Cl, Br, I or alkyl, where R.sub.6 is H or alkyl; R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are independently H, F, Cl Br, I, alkyl or aryl, or two or more of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on a same benzene ring form a bicyclic, tricyclic or tetracyclic moiety with the benzene ring, with the proviso that all of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on the same benzene ring are not H; L is absent or a molecule that coordinates to H.sup.+; and, x is 0 when L is absent, or x is 0.5 or more when L is present.

##STR00001##

[Object] To provide a method for producing a vinyl ether polymer containing a hydrocarbon group in a stable and efficient manner, wherein decomposition of the monomer and generation of polyacetal are suppressed. [Means for solving problem] The method for producing a vinyl ether polymer containing a hydrocarbon group according to the present invention comprises the step of polymerizing vinyl ether represented by the following formula (1): ##STR00001## wherein R.sup.1 represents an aliphatic hydrocarbon group having 1 to 10 carbons or an alicyclic hydrocarbon group having 3 to 10 carbons,
in the presence of water as a polymerization solvent and an organic azo-based compound as a radical polymerization initiator, under pH of 6 or more.

[Object] To provide a method for producing a vinyl ether polymer containing a hydrocarbon group in a stable and efficient manner, wherein decomposition of the monomer and generation of polyacetal are suppressed. [Means for solving problem] The method for producing a vinyl ether polymer containing a hydrocarbon group according to the present invention comprises the step of polymerizing vinyl ether represented by the following formula (1): ##STR00001## wherein R.sup.1 represents an aliphatic hydrocarbon group having 1 to 10 carbons or an alicyclic hydrocarbon group having 3 to 10 carbons,
in the presence of water as a polymerization solvent and an organic azo-based compound as a radical polymerization initiator, under pH of 6 or more.

What are described are copolymers obtainable from the free-radical copolymerization at least of the following components: a) cationic monomers selected from the group consisting of cationic (meth)acrylamide monomers and diallyldimethylammonium chloride, b) polyethylene glycol macromonomers, and c) uncharged acrylamide monomers.

The copolymers are advantageously suitable, for example, for use in detergent compositions and lead to advantageous shine results, for example, after application on hard surfaces.

What are described are copolymers obtainable from the free-radical copolymerization at least of the following components: a) cationic monomers selected from the group consisting of cationic (meth)acrylamide monomers and diallyldimethylammonium chloride, b) polyethylene glycol macromonomers, and c) uncharged acrylamide monomers.

The copolymers are advantageously suitable, for example, for use in detergent compositions and lead to advantageous shine results, for example, after application on hard surfaces.

The present invention relates to a refrigerator oil containing a polyvinyl ether-based compound (A) containing a structural unit (a1) having a methoxy group in a side chain thereof in an amount of 30 mol % or more and 100 mol % or less on a basis of 100 mol % of the whole amount of structural units excluding a terminal structural unit in a molecular structure thereof, a refrigerator oil composition containing the refrigerator oil, and a production method of the refrigerator oil.

The present invention relates to a refrigerator oil containing a polyvinyl ether-based compound (A) containing a structural unit (a1) having a methoxy group in a side chain thereof in an amount of 30 mol % or more and 100 mol % or less on a basis of 100 mol % of the whole amount of structural units excluding a terminal structural unit in a molecular structure thereof, a refrigerator oil composition containing the refrigerator oil, and a production method of the refrigerator oil.

An ether polymer satisfies 5m/n1000, n denoting a mass of the ether polymer in units of g, and m denoting a mass of a first substance in units of g. The first substance is obtained by adding the ether polymer to a first solvent at 45 C. to form an ether polymer system, which is allowed to stand at 45 C. for 8 h and then at 25 C. for 24 h, and filtered through a 200-mesh filter, leaving a filter-out substance as the first substance.