Low refractive index and high dispersion material which can produce a bonded-multilayer DOE having an excellent optical performance is obtained, and the optical member using this is obtained. The resin precursor for optical materials obtained through the addition reaction of the composite containing a di (meth) acrylate shown in the following Chemical Expression 1. ##STR00001## where, RH or CH.sub.3, and m+n=1 to 10.

Low refractive index and high dispersion material which can produce a bonded-multilayer DOE having an excellent optical performance is obtained, and the optical member using this is obtained. The resin precursor for optical materials obtained through the addition reaction of the composite containing a di (meth) acrylate shown in the following Chemical Expression 1. ##STR00001## where, RH or CH.sub.3, and m+n=1 to 10.

Radiopaque polymer compositions and methods for making the compositions are provided. These radiopaque polymer compositions include polymer compositions comprising a crosslinked polymer network, the network comprising a first repeating unit derived from a monofunctional monomer and a second repeating unit derived from a multifunctional non-iodinated monomer wherein neither of the two monomers is fluorinated. Devices formed from radiopaque polymer compositions are also provided.

Disclosed is a resin comprising a structural unit derived from a compound represented by formula (I) and a structural unit having an acid-labile group:

##STR00001## ##STR00002##

wherein R.sup.1 and R.sup.2 each independently represent an alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom,

Ar represents an aromatic hydrocarbon group which may have a substituent,

L.sup.1 represents a group represented by formula (X.sup.1-1), etc.,

L.sup.11, L.sup.13, L.sup.15 and L.sup.17 each independently represent an alkanediyl group,

L.sup.12, L.sup.14, L.sup.16 and L.sup.18 each independently represent O, CO, COO, OCO or OCOO, and

* and ** are bonds, and ** represents a bond to an iodine atom.

Disclosed is a resin comprising a structural unit derived from a compound represented by formula (I) and a structural unit having an acid-labile group:

##STR00001## ##STR00002##

wherein R.sup.1 and R.sup.2 each independently represent an alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom,

Ar represents an aromatic hydrocarbon group which may have a substituent,

L.sup.1 represents a group represented by formula (X.sup.1-1), etc.,

L.sup.11, L.sup.13, L.sup.15 and L.sup.17 each independently represent an alkanediyl group,

L.sup.12, L.sup.14, L.sup.16 and L.sup.18 each independently represent O, CO, COO, OCO or OCOO, and

* and ** are bonds, and ** represents a bond to an iodine atom.

The present disclosure relates to a photo-curable composition, a cured product thereof, and an optical member and a display device comprising same. The photo-curable composition has excellent low refractive index, light transmittance, and low haze characteristics by comprising a first olefinic monomer containing fluorine, a second olefinic monomer having an absolute viscosity of 7 cP or less at 25? C., a photo-polymerization initiator, and an amine compound.

A monomer has the structure ##STR00001##
wherein R is an organic group comprising a polymerizable carbon-carbon double bond or carbon-carbon triple bond; X and Y are independently at each occurrence hydrogen or a non-hydrogen substituent; EWG1 and EWG2 are independently at each occurrence an electron-withdrawing group; p is 0, 1, 2, 3, or 4; n is 1, 2, 3, or 4; and M.sup.+ is an organic cation. A polymer prepared from monomer is useful as a component of a photoresist composition.

Radiopaque polymer compositions and methods for making the compositions are provided. These radiopaque polymer compositions include polymer compositions comprising a crosslinked polymer network, the network comprising a first repeating unit derived from a monofunctional monomer and a second repeating unit derived from a multifunctional non-iodinated monomer wherein neither of the two monomers is fluorinated. Devices formed from radiopaque polymer compositions are also provided.

To provide a water/oil repellent composition whereby it is possible to obtain an article which is excellent in each of water repellency, oil repellency and heavy rain durability, a method for its production, and an article which is excellent in each of water repellency, oil repellency, heavy rain durability and texture. The water/oil repellent composition comprises a copolymer containing structural units based on a monomer (a), structural units based on a monomer (b) and structural units based on a monomer (c). Here, the monomer (a) is a compound represented by (ZY).sub.nX (wherein Z is a C.sub.1-6perfluoroalkyl group, etc.; Y is a bivalent organic group, etc.; n is 1 or 2; and X is a polymerizable unsaturated group). The monomer (b) is a (meth)acrylate having no polyfluoroalkyl group and having an alkyl group with at least 12 carbon atoms. The monomer (c) is a monomer having a poly(oxypolyfluoroalkylene) chain.

A method for preparing a core-shell copolymer includes: preparing a core by polymerizing a conjugated diene-based monomer and adding an initiator including two or more peroxide-based functional groups when a polymerization conversion rate is 95% or more and less than 100%; and preparing a core-shell copolymer by polymerizing an alkyl (meth)acrylate monomer in the presence of the core and a macro initiator having a weight average molecular weight of 4,000 g/mol to 50,000 g/mol, wherein the initiator is added in an amount of more than 0 parts by weight and less than 2.5 parts by weight based on 100 parts by weight of the conjugated diene-based monomer, and the macro initiator is added in an amount of more than 0 parts by weight and less than 3.5 parts by weight based on 100 parts by weight of the alkyl (meth)acrylate monomer.