[Object] To provide a method for producing a vinyl ether polymer having a hydroxyl group on the side chain, wherein the vinyl ether polymer having a low viscosity and excellent workability and processability is produced in a simple and efficient method.

[Means for solving problem] The present invention relates to a method for producing a vinyl ether polymer having a hydroxyl group on the side chain, characterized in that vinyl ether comprising a hydroxyl group is subjected to radical polymerization by using an oil-soluble azo polymerization initiator, in the presence of a mixed solvent comprising water and an organic solvent selected from alcohol or cyclic ether radical polymerization.

To provide a novel fluorinated aromatic compound having at least two carbon-carbon unsaturated bonds, a method for its production, a curable material comprising the fluorinated aromatic compound, a cured product thereof, and an optical member. The fluorinated aromatic compound is represented by formula (A), wherein n is an integer of 0 to 6, a is an integer of 0 to 5, b is an integer of 0 to 4, c is an integer of 0 to 4, a+c+n is 2 to 6, a+b is 2 to 9, Z is a single bond, O, S, CO, C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, SO, or SO.sub.2, Rf.sup.1 is a C.sub.1-8 fluoroalkyl group, Y.sup.1 and Y.sup.2 are each independently a group represented by formula (1) (s is 0 or 1, and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each independently a hydrogen atom or a fluorine atom), and F in the aromatic ring indicates that hydrogen atoms in the aromatic ring are all substituted by fluorine atoms. ##STR00001##

To provide a novel fluorinated aromatic compound having at least two carbon-carbon unsaturated bonds, a method for its production, a curable material comprising the fluorinated aromatic compound, a cured product thereof, and an optical member. The fluorinated aromatic compound is represented by formula (A), wherein n is an integer of 0 to 6, a is an integer of 0 to 5, b is an integer of 0 to 4, c is an integer of 0 to 4, a+c+n is 2 to 6, a+b is 2 to 9, Z is a single bond, O, S, CO, C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, SO, or SO.sub.2, Rf.sup.1 is a C.sub.1-8 fluoroalkyl group, Y.sup.1 and Y.sup.2 are each independently a group represented by formula (1) (s is 0 or 1, and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each independently a hydrogen atom or a fluorine atom), and F in the aromatic ring indicates that hydrogen atoms in the aromatic ring are all substituted by fluorine atoms. ##STR00001##

A fluororesin having excellent storage stability with a solvent and adhesion to a base material; a method of its production; a composition including the fluororesin and a solvent; and an article including the composition. The fluororesin includes a polymer having a fluorine-containing aliphatic ring structure within a main chain comprising at least one of an alkoxycarbonyl group having an alkoxy group of 1 to 3 carbon atoms and an amide group having a coupling group. An IR spectrum of a 200 m thick cast film of the fluororesin satisfies 0.010B/A0.7 where A is a local maximum absorbance at 1,780 to 1,800 cm.sup.1, measured from a straight line connecting an absorbance at 1,700 cm.sup.1 and an absorbance at 1,925 cm.sup.1, and B is an absorbance at 1,720 cm.sup.1, measured from a straight line connecting an absorbance at 1,647 cm.sup.1 and an absorbance at 1,763 cm.sup.1.

A liquid developer containing a curable insulating liquid, a cationic polymerization initiator, and a toner particle containing a binder resin and carbon black, wherein the carbon black is basic, or wherein the toner particle contains a carbon black dispersing agent, and the carbon black dispersing agent has a dispersing group and an adsorptive group, and the adsorptive group is an amino group.

Provided is an adhesive for use in an ultraviolet-light-emitting device using ultraviolet light having a wavelength of from 200 to 400 nm as a light source, which can attach adherends made of a polymer having a fluorine-containing alicyclic structure with excellent adhesiveness which is unlikely to be impaired by exposure to such ultraviolet light or heat.

An adhesive for forming an adhesive joint in an ultraviolet-light-emitting device, which is either the following adhesive (A) or the following adhesive (B) comprising a fluoropolymer having a fluorine-containing alicyclic structure; the adhesive (A): an adhesive in which the glass transition temperature of the fluoropolymer is from 30 to 100 C., and which does not contain an ultraviolet-shielding agent; and the adhesive (B): an adhesive comprising the fluoropolymer and an ultraviolet-shielding agent.