Provided is a polycarbonate-polyorganosiloxane copolymer, including: a polyorganosiloxane block (A-1) including a specific structural unit; and a polycarbonate block (A-2) formed of a specific repeating unit, wherein the polycarbonate-polyorganosiloxane copolymer satisfies the following condition (A) or (B): condition (A): a hexane extraction amount of the polycarbonate-polyorganosiloxane copolymer is 150 ppm or less; and condition (B): average weights of polyorganosiloxane blocks in polycarbonate-polyorganosiloxane copolymers obtained by separating the polycarbonate-polyorganosiloxane copolymer with a gel permeation chromatograph satisfy a specific expression.

Provided is a polycarbonate-polyorganosiloxane copolymer, including: a polyorganosiloxane block (A-1) including a specific structural unit; and a polycarbonate block (A-2) formed of a specific repeating unit, wherein the polycarbonate-polyorganosiloxane copolymer satisfies the following condition (A) or (B): condition (A): a hexane extraction amount of the polycarbonate-polyorganosiloxane copolymer is 150 ppm or less; and condition (B): average weights of polyorganosiloxane blocks in polycarbonate-polyorganosiloxane copolymers obtained by separating the polycarbonate-polyorganosiloxane copolymer with a gel permeation chromatograph satisfy a specific expression.

A curable organosilicon resin composition includes; (A) an organopolysiloxane having a resin structure containing 10 to 60 mol % of an R.sup.1SiO.sub.3/2 unit, 30 to 80 mol % of an (R.sup.2).sub.2SiO.sub.2/2 unit, and 1 to 30 mol % of an (R.sup.3).sub.3SiO.sub.1/2 unit. At least a part of the (R.sup.2).sub.2SiO.sub.2/2 unit is in continuous repeating units with the average number of the repeating units being 3 to 80. The organopolysiloxane has a weight average molecular weight of 5,000 to 50,000; the amount of the hydroxy groups bonded to silicon atoms is 0.001 to 1.0 mol/100 g; and the amount of the alkoxy groups, each having 1 to 10 carbon atoms, bonded to silicon atoms is 1.0 mol/100 g or less. A curable organosilicon resin composition has excellent workability, can give a cured product rapidly, and can make the cured product excellent in mechanical properties, heat resistance, crack resistance, and adhesive property, the surface tackiness being suppressed.

A curable organosilicon resin composition includes; (A) an organopolysiloxane having a resin structure containing 10 to 60 mol % of an R.sup.1SiO.sub.3/2 unit, 30 to 80 mol % of an (R.sup.2).sub.2SiO.sub.2/2 unit, and 1 to 30 mol % of an (R.sup.3).sub.3SiO.sub.1/2 unit. At least a part of the (R.sup.2).sub.2SiO.sub.2/2 unit is in continuous repeating units with the average number of the repeating units being 3 to 80. The organopolysiloxane has a weight average molecular weight of 5,000 to 50,000; the amount of the hydroxy groups bonded to silicon atoms is 0.001 to 1.0 mol/100 g; and the amount of the alkoxy groups, each having 1 to 10 carbon atoms, bonded to silicon atoms is 1.0 mol/100 g or less. A curable organosilicon resin composition has excellent workability, can give a cured product rapidly, and can make the cured product excellent in mechanical properties, heat resistance, crack resistance, and adhesive property, the surface tackiness being suppressed.

A crosslinkable composition containing: a liquid monocyclic olefin ring-opened polymer (A) having a reactive group at a polymer chain end thereof and a weight-average molecular weight (Mw) of 1,000 to 50,000; and a crosslinkable compound (B) having, in the molecule, two or more functional groups reactive with the reactive group at the polymer chain end of the monocyclic olefin ring-opened polymer (A).

A crosslinkable composition containing: a liquid monocyclic olefin ring-opened polymer (A) having a reactive group at a polymer chain end thereof and a weight-average molecular weight (Mw) of 1,000 to 50,000; and a crosslinkable compound (B) having, in the molecule, two or more functional groups reactive with the reactive group at the polymer chain end of the monocyclic olefin ring-opened polymer (A).

A low-density gel product of the present disclosure has a skeleton containing a polysiloxane chain and an organic polymer chain. In the skeleton, the polysiloxane chain and the organic polymer chain are bonded to each other by covalent bonds at a plurality of positions on both of the chains with silicon atoms of the polysiloxane chain as bonding points. The organic polymer chain may be an aliphatic hydrocarbon chain. The polysiloxane chain may be a polyorganosiloxane chain. The low-density gel product of the present disclosure is a novel low-density gel product with improved mechanical properties including bending flexibility.

A low-density gel product of the present disclosure has a skeleton containing a polysiloxane chain and an organic polymer chain. In the skeleton, the polysiloxane chain and the organic polymer chain are bonded to each other by covalent bonds at a plurality of positions on both of the chains with silicon atoms of the polysiloxane chain as bonding points. The organic polymer chain may be an aliphatic hydrocarbon chain. The polysiloxane chain may be a polyorganosiloxane chain. The low-density gel product of the present disclosure is a novel low-density gel product with improved mechanical properties including bending flexibility.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof:
Gr1-Ar1-X1-(Y1).sub.n1  (I)
in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—, ##STR00001##
—CO—, —COO—, —CONH—, and an arylene group.

The modified graphene includes a structure represented by the following formula (I), wherein the modified graphene has a ratio (g/d) of an intensity “g” of a G band to an intensity “d” of a D band of 1.0 or more in a Raman spectroscopy spectrum thereof:
Gr1-Ar1-X1-(Y1).sub.n1  (I)
in the formula (I), Gr1 represents a single-layer graphene or a multilayer graphene, Ar1 represents an arylene group having 6 to 18 carbon atoms, X1 represents a single bond, a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms, or a group obtained by substituting at least one carbon atom in a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms with at least one structure selected from the group consisting of —O—, —NH—, ##STR00001##
—CO—, —COO—, —CONH—, and an arylene group.