An object of the present invention is to provide a photocurable resin composition having a high curing degree after irradiation with light while maintaining cured material characteristics such as high extensibility and high strength. Provided is a photocurable resin composition including the following ingredients (A) to (C): ingredient (A): a polyisobutylene resin containing one or more (meth)acryloyl groups and a —[CH.sub.2C(CH.sub.3).sub.2]— unit; ingredient (B): ingredient (b1): an acrylate monomer having an alicyclic hydrocarbon group having 5 to 25 carbon atoms, and ingredient (b2): an acrylate monomer having a linear or branched alkyl group having 11 to 30 carbon atoms; and ingredient (C): a photo-radical polymerization initiator.

An object of the present invention is to provide a photocurable resin composition having a high curing degree after irradiation with light while maintaining cured material characteristics such as high extensibility and high strength. Provided is a photocurable resin composition including the following ingredients (A) to (C): ingredient (A): a polyisobutylene resin containing one or more (meth)acryloyl groups and a —[CH.sub.2C(CH.sub.3).sub.2]— unit; ingredient (B): ingredient (b1): an acrylate monomer having an alicyclic hydrocarbon group having 5 to 25 carbon atoms, and ingredient (b2): an acrylate monomer having a linear or branched alkyl group having 11 to 30 carbon atoms; and ingredient (C): a photo-radical polymerization initiator.

The present disclosure provides a sealing member that includes insertion holes into which connector terminals are inserted, wherein the sealing member exhibits a high water sealability and damage caused when the connector terminal is inserted into the insertion hole is suppressed. The present disclosure also provides a waterproof connector that includes the sealing member. A sealing member 10 includes: a silicone rubber that is formed as a plate-like member; and insertion holes 11 that are formed in a plate surface of the plate-like member and into which connector terminals 20 can be inserted. The silicone rubber has an unnotched Charpy impact strength at −60° C. of 11.5 kJ/mm.sup.2 or more. A waterproof connector 1 includes the sealing member 10 and the connector terminals 20. The connector terminals 20 are inserted into the insertion holes 11 of the sealing member 10.

The present disclosure provides a sealing member that includes insertion holes into which connector terminals are inserted, wherein the sealing member exhibits a high water sealability and damage caused when the connector terminal is inserted into the insertion hole is suppressed. The present disclosure also provides a waterproof connector that includes the sealing member. A sealing member 10 includes: a silicone rubber that is formed as a plate-like member; and insertion holes 11 that are formed in a plate surface of the plate-like member and into which connector terminals 20 can be inserted. The silicone rubber has an unnotched Charpy impact strength at −60° C. of 11.5 kJ/mm.sup.2 or more. A waterproof connector 1 includes the sealing member 10 and the connector terminals 20. The connector terminals 20 are inserted into the insertion holes 11 of the sealing member 10.

An ultra-white granular silica-based filler comprises at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the silica-based filler comprises 40 to 80 wt. % cristobalite, 1 to 25 wt. % tridymite, 2-60 wt. % quartz and <5 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is no higher than 50° C. and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98. In addition, an ultra-white powder filler is obtained by milling, grinding or comminuting the ultra-white granular silica-based filler. The ultra-white powder filler exhibits an L* value in the CIELAB color space of 95-98.5.

An ultra-white granular silica-based filler comprises at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the silica-based filler comprises 40 to 80 wt. % cristobalite, 1 to 25 wt. % tridymite, 2-60 wt. % quartz and <5 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is no higher than 50° C. and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98. In addition, an ultra-white powder filler is obtained by milling, grinding or comminuting the ultra-white granular silica-based filler. The ultra-white powder filler exhibits an L* value in the CIELAB color space of 95-98.5.

A member for a fuel cell in which a lip 4b is directly fixed to the surface of a separator 5. In the member for a fuel cell, the lip 4b is a cross-linked body of a radically curable composition containing components (A) to (E) below at a specific ratio, and the glass transition temperature (Tg) of the cross-linked body is −30° C. or less. (A) (Meth)acrylic polymer having a (meth)acryloyl group at a molecular chain end. (B) Monofunctional (meth)acrylic monomer having a glass transition temperature (Tg) of 0° C. or more and having a polycyclic structure. (C) Monofunctional (meth)acrylic monomer except for component (B). (D) Polyfunctional (meth)acrylic monomer. (E) Radical polymerization initiator.

Improved polysulfide sealant formulations, application of such sealants, and methods for reducing the density of polysulfide sealant formulations are disclosed.

Hydroxyl-containing bis(alkenyl) ethers can be incorporated into the backbone of polythioether prepolymers and can be used as curing agents in thiol-terminated polythioether prepolymer compositions. Cured sealants prepared using compositions containing hydroxyl-containing bis(alkenyl) ether-containing polythioether prepolymers and/or hydroxyl-containing bis(alkenyl) ether curing agents exhibit improved physical properties such as rapid curing and compatibility with fillers suitable for use in aerospace sealant applications.

A roofing membrane and a method of making the same is provided. The roofing membrane includes a top layer having a flame retardant and a first silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm.sup.3; a scrim layer; and a bottom layer having a flame retardant and a second silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm.sup.3. The top and bottom layers of the roofing membrane both exhibit a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).