The present invention aims to provide a viscosity-index improving agent capable of providing a lubricating oil composition having an appropriate gelation index, an excellent HTHS viscosity at 100° C., and an excellent kinematic viscosity at 40° C. when the viscosity-index improving agent is added thereto. The present also aims to provide a lubricating oil composition containing the viscosity-index improving agent. The present invention relates to, for example, a viscosity-index improving agent containing a copolymer (A) and an ester oil (Z), the copolymer A containing, as constituent monomers, a polyolefin-based monomer (a) represented by the following formula (1), a monomer (b) represented by the following formula (2) in which R.sup.4 is a C4 alkyl group, and at least one of a monomer (c) represented by the following formula (3) and a monomer (d) represented by the following formula (2) in which R.sup.4 is a C2-C3 alkyl group:

##STR00001##

wherein R.sup.1 is a hydrogen atom or a methyl group; —X.sup.1— is a group represented by —O—, —O(AO).sub.m—, or —NH—, A is a C2-C4 alkylene group, m is an integer of 1 to 10, and each A may be the same or different when m is 2 or more; R.sup.2 is a residue after removal of one hydrogen atom from a hydrocarbon polymer containing a 1,2-butylene group as a structural unit; and p represents a number of 0 or 1;

##STR00002##

wherein R.sup.3 is a hydrogen atom or a methyl group; —X.sup.2— is a group represented by —O— or —NH—; and R.sup.4 is a C2-C4 alkyl group;

##STR00003##

wherein R.sup.5 is a hydrogen atom or a methyl group; —X.sup.3— is a group represented by —O— or —NH—; R.sup.6 is a C2-C4 alkylene group; R.sup.7 is a C1-C8 alkyl group; and r is an integer of 1 to 20, and each R.sup.6 may be the same or different when r is 2 or more.

Provided are an adhesive resin composition capable of forming an adhesive layer excellent in holding force, wet heat clouding resistance, and low corrosiveness; and an adhesive sheet. The adhesive resin composition includes a (meth)acrylic copolymer (A) having a constituent unit derived from a macromonomer (a) and a constituent unit derived from a vinyl monomer (b), in which the (meth)acrylic copolymer (A) has at least one of an amide bond and a radical polymerizable group.

Provided are an adhesive resin composition capable of forming an adhesive layer excellent in holding force, wet heat clouding resistance, and low corrosiveness; and an adhesive sheet. The adhesive resin composition includes a (meth)acrylic copolymer (A) having a constituent unit derived from a macromonomer (a) and a constituent unit derived from a vinyl monomer (b), in which the (meth)acrylic copolymer (A) has at least one of an amide bond and a radical polymerizable group.

A quadripolymer based on host-guest interaction and prepared in the steps including (1) weigh maleic anhydride and dissolve in dichloromethane, add β-phenethylamine dropwise, stir to react for 1 to 3 hours, perform extraction filtration and washing, to obtain N-phenethylmaleamic acid; (2) weigh mono 6-ethylenediamine β-cyclodextrin and maleic anhydride, dissolve in N, N-dimethylformamide, and place at 40° C. for reaction for 3 to 6 hours, the product is precipitated with chloroform, washed and dried under vacuum to obtain maleic anhydride modified mono 6-ethylenediamine β-cyclodextrin; (3) Add acrylamide, acrylic acid, maleic anhydride modified mono 6-ethylenediamine β-cyclodextrin, N-phenethylmaleamic acid, adjust the pH of the solution to 7; introduce nitrogen, add a photoinitiator and place to a photo-initiating device to react 3˜5 hours at a temperature of 10˜30° C. The quadripolymer has good temperature and salt resistance, shear resistance. The raw materials are cheap and easily available. The reaction conditions are mild.

The present invention aims to provide a photocurable resin composition which rapidly cures by irradiation with active energy rays such as ultraviolet rays and is excellent in adhesion to an electrolyte membrane which is a hard-to-bond material. A photocurable resin composition includes the following ingredients (A) to (C): ingredient (A): a polymer having one or more (meth)acryloyl groups and having a polyisobutylene skeleton containing a —[CH.sub.2C(CH.sub.3).sub.2]— unit, ingredient (B): a photoradical polymerization initiator, and ingredient (C): a compound having a (meth)acryloyl group and a cationic polymerizable functional group in one molecule.

The present invention aims to provide a photocurable resin composition which rapidly cures by irradiation with active energy rays such as ultraviolet rays and is excellent in adhesion to an electrolyte membrane which is a hard-to-bond material. A photocurable resin composition includes the following ingredients (A) to (C): ingredient (A): a polymer having one or more (meth)acryloyl groups and having a polyisobutylene skeleton containing a —[CH.sub.2C(CH.sub.3).sub.2]— unit, ingredient (B): a photoradical polymerization initiator, and ingredient (C): a compound having a (meth)acryloyl group and a cationic polymerizable functional group in one molecule.

A composition that cures when exposed to actinic radiation. In some embodiments the curable adhesive composition comprises: a) one or more radiation curable oligomers or prepolymers terminally having at least one carbon-carbon double bond-containing group; b) one or more diluent monomer components containing at least one polymerizable group; c) optionally one or more adhesion promoting additives of an organic or inorganic acid acrylic monomer; and optionally one or more rheological modifiers; one or more plasticizers and; one or more additives. The curable composition can be used in an adhesive that structurally bonds many substrates including dissimilar substrates. In some embodiments cured reaction products of the composition have a broad service temperature range from 20 to 120 C. Cured reaction products of this embodiment will exhibit greater than 50% cohesive failure in this temperature range. The cured composition will retain adhesive strength at temperatures above its Tg.

Provided is a hydrogel-forming composition capable of forming a sterilized hydrogel having a high mechanical strength. Also provided are a hydrogel using the hydrogel-forming composition, and a method for producing the hydrogel-forming composition. The hydrogel-forming composition contains a vinyl alcohol polymer having an ethylenically unsaturated group and having a polymerization degree of 450 or more, in which the ethylenically unsaturated group introduction ratio is 0.01 to 10 mol % in all the structural units constituting the vinyl alcohol polymer, and in which no microorganisms detectable by the sterility test method (direct method) specified in the general test methods of the Japanese Pharmacopoeia are present.

An object of the present invention is to provide a curable resin composition having a low viscosity and capable of obtaining a cured material having excellent compression set. The curable resin composition of the present invention contains the following components (A) to (C): component (A): an oligomer having one or more (meth)acryloyl groups and a polyisobutylene skeleton containing a —[CH2C(CH3)2]—unit, component (B): a monofunctional monomer having a (meth)acryloyloxy group and a saturated heterocycle with a 4 or more membered ring, component (C): a radical polymerization initiator.

An object of the present invention is to provide a curable resin composition having a low viscosity and capable of obtaining a cured material having excellent compression set. The curable resin composition of the present invention contains the following components (A) to (C): component (A): an oligomer having one or more (meth)acryloyl groups and a polyisobutylene skeleton containing a —[CH2C(CH3)2]—unit, component (B): a monofunctional monomer having a (meth)acryloyloxy group and a saturated heterocycle with a 4 or more membered ring, component (C): a radical polymerization initiator.