This disclosure provides a rubber composition that can realize excellent low heat generating properties without deteriorating other performance. The rubber composition contains a rubber component and a filler, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1).

##STR00001##

This disclosure provides a rubber composition that can realize excellent low heat generating properties without deteriorating other performance. The rubber composition contains a rubber component and a filler, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1).

##STR00001##

A resin sheet is provided having low dielectric properties, and a circuit board material using such a sheet. The resin sheet includes a resin layer containing a cyclic polyolefin resin copolymer having a crystal melting peak temperature of less than 100° C., the resin sheet having a dielectric loss tangent at 12 GHz of less than 0.005.

A resin sheet is provided having low dielectric properties, and a circuit board material using such a sheet. The resin sheet includes a resin layer containing a cyclic polyolefin resin copolymer having a crystal melting peak temperature of less than 100° C., the resin sheet having a dielectric loss tangent at 12 GHz of less than 0.005.

A resin composition includes: a compound represented by Formula (1); and a resin, in the formula, A and B each independently represent an aromatic hydrocarbon ring or an aromatic heterocycle, Ra and Rb each independently represent a substituent, m1 represents an integer of 0 to mA, m2 represents an integer of 0 to mB, Y.sup.1 and Y.sup.2 each independently represent an alkyl group, an aryl group, a group represented by Formula (Y-1), or a group represented by Formula (Y-2), and at least one of Y.sup.1 or Y.sup.2 represents a group represented by Formula (Y-1) or a group represented by Formula (Y-2). ##STR00001##

A resin composition includes: a compound represented by Formula (1); and a resin, in the formula, A and B each independently represent an aromatic hydrocarbon ring or an aromatic heterocycle, Ra and Rb each independently represent a substituent, m1 represents an integer of 0 to mA, m2 represents an integer of 0 to mB, Y.sup.1 and Y.sup.2 each independently represent an alkyl group, an aryl group, a group represented by Formula (Y-1), or a group represented by Formula (Y-2), and at least one of Y.sup.1 or Y.sup.2 represents a group represented by Formula (Y-1) or a group represented by Formula (Y-2). ##STR00001##

A rubber compound having at least two glass transition temperatures Tg1 and Tg2 is based on at least two rubber compositions C1 and C2, C1 comprising at least one elastomer E1 with Tg1, C2 comprising at least one elastomer E2 with Tg2 and a reinforcing filler, E2 being different from E1, where Tg1 is above or equal to -50° C., the rubber compound satisfies Tg1-Tg2 ≥ 23° C. and has a loss factor profile exhibiting the change in tan δ as a function of the temperature in °C. over a range extending from -80° C. to 60° C. at a frequency of 10 Hz and a constant stress of 0.7 MPa and exhibiting one or more peaks, such that all the tan δ peaks present at a temperature above Tg1 have a width at half height less than or equal to 23° C.; and E1 is predominant.

A rubber compound having at least two glass transition temperatures Tg1 and Tg2 is based on at least two rubber compositions C1 and C2, C1 comprising at least one elastomer E1 with Tg1, C2 comprising at least one elastomer E2 with Tg2 and a reinforcing filler, E2 being different from E1, where Tg1 is above or equal to -50° C., the rubber compound satisfies Tg1-Tg2 ≥ 23° C. and has a loss factor profile exhibiting the change in tan δ as a function of the temperature in °C. over a range extending from -80° C. to 60° C. at a frequency of 10 Hz and a constant stress of 0.7 MPa and exhibiting one or more peaks, such that all the tan δ peaks present at a temperature above Tg1 have a width at half height less than or equal to 23° C.; and E1 is predominant.

A flowable hardenable composition comprising from 10 to 95 percent by volume of shaped composite particles dispersed in a hardenable binder precursor. The shaped composite particles comprise thermal filler particles having an aspect ratio of at least 1.5 retained in a binder matrix. After hardening, a thermally conductive composition is obtained. An electronic heat sink assembly comprises an electronic component, a heat sink, and the thermally conductive composition sandwiched therebetween.

A flowable hardenable composition comprising from 10 to 95 percent by volume of shaped composite particles dispersed in a hardenable binder precursor. The shaped composite particles comprise thermal filler particles having an aspect ratio of at least 1.5 retained in a binder matrix. After hardening, a thermally conductive composition is obtained. An electronic heat sink assembly comprises an electronic component, a heat sink, and the thermally conductive composition sandwiched therebetween.