To offer curable silicone compositions with outstandingly high thixotropy, which can form hardened material with an outstanding refractive index transparency.

The problem above is solved by curable silicone compositions which include (A) alkenyl group-containing organopolysiloxane which has at least two silicon-bonded alkenyl groups per molecule, (B) organo-hydrogen polysiloxane which has at least two silicon-bonded hydrogen atoms per molecule, (C) silica-titania composite oxide particles at ≥3 mass % of the total mass of the composition, and (D) a curing catalyst.

Provided are a resin composition for sealing an optical semiconductor providing both UV transmission and heat resistance, and a molded resin product for sealing an optical semiconductor, an optical semiconductor-sealing material, and an optical semiconductor device each including the same. The resin composition satisfies the relationship X=(A1×A2)/A3+(B1×B2)/B3+ . . . <0.0005 wherein A1 represents the mass ratio of an aromatic compound, A2 represents the number of aromatic rings per molecule of the aromatic compound, A3 represents the molecular weight of the aromatic compound, and A, B, . . . each represent an aromatic compound. The composition contains an epoxy, an alicyclic acid anhydride, and an antioxidant. When formed into a cured product (size: 50 mm in width×50 mm in length×1 mm in thickness), a linear transmittance at 300 nm is 80% or higher and a linear transmittance at 400 nm is 95% or higher.

A high-purity barium titanate powder according to the present invention has a Cl.sup.− concentration of 20 ppm or less, an electric conductivity of extracted water of 70 μS/cm or less, and an average particle diameter of 1 μm to 30 μm.

A high-purity barium titanate powder according to the present invention has a Cl.sup.− concentration of 20 ppm or less, an electric conductivity of extracted water of 70 μS/cm or less, and an average particle diameter of 1 μm to 30 μm.

Provided is a resin composition, which is fast curable at low temperature, has high adhesive strength (especially, high peel strength) after curing, and can suppress a decrease in adhesive strength (especially, in peel strength) after a moisture resistance test of the resin composition after curing, and further has excellent pot life. Provided is the resin composition including: (A) an epoxy resin; (B) a thiol compound represented by C(CH.sub.2OR.sup.1)(CH.sub.2OR.sup.2)(CH.sub.2OR.sup.3)(CH.sub.2OR.sup.4) (wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen or C.sub.nH.sub.2nSH (wherein n is 2 to 6), at least one of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is C.sub.nH.sub.2nSH (wherein n is 2 to 6)); (b) a polyfunctional thiol compound other than the (B); and (C) a latent curing accelerator.

A fire-stopping material for use in sandwich panels is provided, wherein the fire-stopping material comprises a resilient, porous material at least partially impregnated with an intumescent agent. A panel for an internal wall and an internal wall are also provided, comprising the fire-stopping material disposed between two substantially parallel boards, such as plaster boards. A method of providing a service penetration through an internal wall is also provided.

A polymer having a hydrophobic polymer chain derived from monomers of farnesene and other optional monomers, such as dienes and vinyl aromatics. The polymer also includes one or more terminal functional groups, such as an amino group, a glycidyl group, a carboxylic acid group, a (meth)acrylate group, a silane group, an isocyanate group, an acetoacetate group, a phenolic group, and a hydroxyl group. Functional groups, such as carboxylic acids, may also be grafted along the hydrophobic polymer chain. The polymer may be incorporated in curable compositions that optionally include one or more polymer resins having similar functional groups. Methods for preparing the curable polymer compositions are also provided. The curable or cured form of the polymer composition may be used in various products, such as a sealant, a coating, a caulk, an electric potting compound, a membrane, a sponge, a foam, an adhesive, or a propellant binder.

Provided are a novel acrylic polymer that has moderate crosslinking reactivity and is suitable for sealant applications and a sealant using the polymer. The (meth)acrylic acid alkyl ester polymer according to the invention has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) method of 30,000 to 150,000 and a number average molecular weight (Mn) of less than 20,000 and has 1.1 to 3.0 methyldimethoxysilyl groups, more than 0.5 methyldimethoxysilyl groups at side chains of a molecular chain, and more than 0.5 methyldimethoxysilyl groups at molecular chain terminals, per one molecule of the polymer.

Provided are a novel acrylic polymer that has moderate crosslinking reactivity and is suitable for sealant applications and a sealant using the polymer. The (meth)acrylic acid alkyl ester polymer according to the invention has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) method of 30,000 to 150,000 and a number average molecular weight (Mn) of less than 20,000 and has 1.1 to 3.0 methyldimethoxysilyl groups, more than 0.5 methyldimethoxysilyl groups at side chains of a molecular chain, and more than 0.5 methyldimethoxysilyl groups at molecular chain terminals, per one molecule of the polymer.

A resin composition includes polyetheretherketone, a polyetheretherketone recycled material, and a filler, wherein a percentage of the recycled material is 25 mass % or higher with respect to a total of the polyetheretherketone and the recycled material; and the filler has a content of from 5 to 30 mass % and has an aspect ratio of from 1 to 3.