Provided are methods of forming thermally conductive flexible bonds for use in electronic boards of unmanned spacecraft and other types of aircraft. Also provided are methods of preparing adhesive materials to form these bonds including methods of preparing treated filler particles. In some aspects, an adhesive material includes filler particles having organofunctional groups, such as boron nitride particles treated in silane. These particles may be combined with a urethane modified epoxy to form the adhesive material. The weight ratio of the particles in the adhesive material may be about 40-60%. The adhesive material may be thermally cured using a temperature of less than 110° C. to prevent damage to bonded electronic components. The cured adhesive may have a thermal conductivity of at least about 2 W/m K measured in vacuum and may have a glass transition temperature if less than −40° C.

A composition having: 30% to 35% by weight of a first polydimethylsiloxane having vinyl moieties, wherein at least 0.10% by weight of the first polydimethylsiloxane is attributed to the vinyl moieties; 20% to 25% by weight of a second polydimethylsiloxane having vinyl moieties, wherein at least 0.20% by weight of the second polydimethylsiloxane is attributed to the vinyl moieties; 7% to 10% by weight of a third polydimethylsiloxane having hydroxyl moieties, wherein at least 2.0% by weight of the third polydimethylsiloxane is attributed to the hydroxyl moieties; 22% to 35% by weight fumed silicon dioxide, wherein the fumed silicon dioxide has a surface area of at least 150 square meters per gram; 0.2% to 1.0% by weight a blowing agent; 0.15% to 0.5% by weight active boron; and 0.25% to 1.00% by weight active peroxide.

A composition having: 30% to 35% by weight of a first polydimethylsiloxane having vinyl moieties, wherein at least 0.10% by weight of the first polydimethylsiloxane is attributed to the vinyl moieties; 20% to 25% by weight of a second polydimethylsiloxane having vinyl moieties, wherein at least 0.20% by weight of the second polydimethylsiloxane is attributed to the vinyl moieties; 7% to 10% by weight of a third polydimethylsiloxane having hydroxyl moieties, wherein at least 2.0% by weight of the third polydimethylsiloxane is attributed to the hydroxyl moieties; 22% to 35% by weight fumed silicon dioxide, wherein the fumed silicon dioxide has a surface area of at least 150 square meters per gram; 0.15% to 0.5% by weight active boron; and 0.25% to 1.00% by weight active peroxide.

A thermally conductive sheet includes a resin composition including a silicone rubber, and thermally conductive fillers that are anisotropic, the thermally conductive fillers being dispersed in the silicone rubber. A content of the thermally conductive fillers in the resin composition is 52% by volume or more and 75% by volume or less. Major axes of the thermally conductive fillers are oriented in a thickness direction of the thermally conductive sheet, and a ratio of a peak intensity of a (002) plane to a peak intensity of a (100) plane in a spectrum measured from the thickness direction by an X-ray diffraction method is 0.31 or less.

A highly thermally conductive composition is provided, such composition comprising: (A) An organopolysiloxane composition; (B) a filler treating agent; (C) a thermal stabilizer; and (D) thermally conductive filler mixture, comprising: (D-1) a small-particulate thermally conductive filler having a mean size of up to 3 μm, (D-2) spherical aluminum nitride having a mean size of from 50 to 150 μm, (D-3) boron nitride having a mean size of from 20 to 200 μm.

A highly thermally conductive composition is provided, such composition comprising: (A) An organopolysiloxane composition; (B) a filler treating agent; (C) a thermal stabilizer; and (D) thermally conductive filler mixture, comprising: (D-1) a small-particulate thermally conductive filler having a mean size of up to 3 μm, (D-2) spherical aluminum nitride having a mean size of from 50 to 150 μm, (D-3) boron nitride having a mean size of from 20 to 200 μm.

The present invention provides a polymer film on array (PFA) material and a preparation method thereof. The PFA material includes a polymer film on array (PFA) resin, a polysiloxane resin dispersion liquid, and a solvent, wherein the PFA resin ranges from 1 to 25% by weight relative to a total weight of the PFA material, and the polysiloxane resin dispersion liquid ranges from 1 to 30% by weight relative to a total weight of the PFA material.

The present invention provides a polymer film on array (PFA) material and a preparation method thereof. The PFA material includes a polymer film on array (PFA) resin, a polysiloxane resin dispersion liquid, and a solvent, wherein the PFA resin ranges from 1 to 25% by weight relative to a total weight of the PFA material, and the polysiloxane resin dispersion liquid ranges from 1 to 30% by weight relative to a total weight of the PFA material.

Disclosed is a hexagonal boron nitride powder having excellent glitter property. A hexagonal boron nitride powder includes hexagonal boron nitride particles, in which among the hexagonal boron nitride particles, a number ratio of particles having a bent structure at an angle of 110° to 160° with respect to (0,0,1) crystal plane of the primary particles is 30% or more.

Resin-rich mica tapes comprising one or more than one layer of mica paper and one or more than one layer of a nonmetallic inorganic fabric, in particular a glass fabric, which are pre-impregnated with an impregnation resin composition comprising an epoxy resin with more than one epoxy group, which is solid or semisolid at ambient temperature, a latent curing agent for said epoxy resin, about 5 to about 20% by weight of hexagonal boron nitride of a particle size (D50) of equal or less than about 3 μm, about 0.05 to about 1% by weight of a wetting agent and a suitable solvent which is removed after pre-impregnation of the mica tape with the impregnation resin mixture are useful to prepare electrical insulations with excellent thermal conductivity and dielectric dissipation factor.