Resin composition and use thereof
Provided is a resin composition from which a heat dissipation sheet having high effect to suppress temperature elevation due to heat generated by electronic parts (elements) can be obtained. Specifically provided is a resin composition containing: a polymer (1) whose enthalpy of fusion observed within a temperature range of 10° C. or higher and lower than 60° C. in differential scanning calorimetry is 30 J/g or more; and a thermally conductive material (3) whose thermal conductivity is 1 W/(m·K) or higher, wherein the content of the thermally conductive material (3) is 1 part by weight or more and 80 parts by weight or less, with respect to 100 parts by weight of the total amount of polymer components contained in the resin composition.
1. A resin composition comprising:
a crosslinked polymer (1) whose enthalpy of fusion observed within a temperature range of 10° C. or higher and lower than 60° C. in differential scanning calorimetry is 30 J/g or more;
a polymer (2) whose melting peak temperature or glass transition temperature observed in differential scanning calorimetry is 50° C. or higher and 180° C. or lower, provided that the polymer (2) is different from the polymer (1), and
a thermally conductive material (3) whose thermal conductivity is 1 W/(m·K) or higher, wherein
a content of the crosslinked polymer (1) is 30 wt % or more and 99 wt % or less and a content of the polymer (2) is 1 wt % or more and 70 wt % or less, with respect to 100 wt % of the total amount of the crosslinked polymer (1) and the polymer (2) and
a content of the thermally conductive material (3) is 5 parts by weight or more and 80 parts by weight or less, with respect to 100 parts by weight of the total amount of polymer components contained in the resin composition.
2. The resin composition according to claim 1 , wherein the polymer (1) is a polymer comprising a constitutional unit (B) represented by the following formula (1):
wherein
R represents a hydrogen atom or a methyl group;
L 1 represents a single bond, —CO—O—, —O—CO—, or —O—;
L 2 represents a single bond, —CH 2 —, —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, —CH 2 —CH(OH)—CH 2 —, or —CH 2 —CH(CH 2 OH)—;
L 3 represents a single bond, —CO—O—, —O—CO—, —O—, —CO—NH—, —NH—CO—, —CO—NH—CO—, —NH—CO—NH—, —NH—, or —N(CH 3 )—;
L 6 represents an alkyl group having 14 or more and 30 or less carbon atoms; and
a left side and a right side of each of the horizontal chemical formulas for describing chemical structures of L 1 , L 2 , and L 3 correspond to an upper side of the formula (1) and a lower side of the formula (1), respectively.
3. The resin composition according to claim 1 , wherein
the polymer (1) comprises a constitutional unit (A) derived from ethylene and a constitutional unit (B) represented by the following formula (1), and optionally comprises at least one constitutional unit (C) selected from the group consisting of a constitutional unit represented by the following formula (2) and a constitutional unit represented by the following formula (3);
a proportion of the number of the constitutional unit (A) is 70% or more and 99% or less and a proportion of the number of the constitutional unit (B) and the constitutional unit (C) in total is 1% or more and 30% or less, with respect to 100% of the total number of the constitutional unit (A), the constitutional unit (B) and the constitutional unit (C); and
a proportion of the number of the constitutional unit (B) is 1% or more and 100% or less and a proportion of the number of the constitutional unit (C) is 0% or more and 99% or less, with respect to 100% of the total number of the constitutional unit (B) and the constitutional unit (C):
wherein
R represents a hydrogen atom or a methyl group;
L 1 represents a single bond, —CO—O—, —O—CO—, or —O—;
L 2 represents a single bond, —CH 2 —, —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, —CH 2 —CH(OH)—CH 2 —, or —CH 2 —CH(CH 2 OH)—;
L 3 represents a single bond, —CO—O—, —O—CO—, —O—, —CO—NH—, —NH—CO—, —CO—NH—CO—, —NH—CO—NH—, —NH—, or —N(CH 3 )—;
L 6 represents an alkyl group having 14 or more and 30 or less carbon atoms; and
a left side and a right side of each of the horizontal chemical formulas for describing chemical structures of L 1 , L 2 , and L 3 correspond to an upper side of the formula (1) and a lower side of the formula (1), respectively,
wherein
R represents a hydrogen atom or a methyl group;
L 1 represents a single bond, —CO—O—, —O—CO—, or —O—;
L 4 represents an alkylene group having one or more and eight or less carbon atoms;
L 5 represents a hydrogen atom, an epoxy group, —CH(OH)—CH 2 OH, a carboxy group, a hydroxy group, an amino group, or an alkylamino group having one or more and four or less carbon atoms; and
a left side and a right side of each of the horizontal chemical formulas for describing a chemical structure of L 1 correspond to an upper side of the formula (2) and a lower side of the formula (2), respectively,
4. The resin composition according to claim 3 , wherein a proportion of the number of the constitutional unit (A), the constitutional unit (B) and the constitutional unit (C) in total in the polymer is 90% or more, with respect to 100% of the total number of all constitutional units contained in the polymer (1).
5. The resin composition according to claim 1 , wherein a ratio defined for the polymer (1) as the following formula (I), A, is 0.95 or lower:
A=α 1 /α 0 (I)
wherein
α 1 represents a value obtained by using a method comprising: measuring an absolute molecular weight and an intrinsic viscosity of a polymer by using gel permeation chromatography with an apparatus equipped with a light scattering detector and a viscosity detector; plotting measurements in such a manner that logarithms of the absolute molecular weight are plotted on an abscissa and logarithms of the intrinsic viscosity are plotted on an ordinate; and performing least squares approximation for the logarithms of the absolute molecular weight and the logarithms of the intrinsic viscosity by using the formula (I-I) within a range of not less than a logarithm of a weight-average molecular weight of the polymer and not more than a logarithm of a z-average molecular weight of the polymer along the abscissa to derive a slope of a line representing the formula (I-I) as α 1 :
log[η 1 ]=α 1 log M 1 +log K 1 (I-I)
wherein
[η 1 ] represents an intrinsic viscosity (unit: dl/g) of the polymer, M 1 represents an absolute molecular weight of the polymer, and K 1 represents a constant; and
α 0 represents a value obtained by using a method comprising: measuring an absolute molecular weight and an intrinsic viscosity of Polyethylene Standard Reference Material 1475a produced by National Institute of Standards and Technology by using gel permeation chromatography with an apparatus equipped with a light scattering detector and a viscosity detector; plotting measurements in such a manner that logarithms of the absolute molecular weight are plotted on an abscissa and logarithms of the intrinsic viscosity are plotted on an ordinate; and performing least squares approximation for the logarithms of the absolute molecular weight and the logarithms of the intrinsic viscosity by using the formula (I-II) within a range of not less than a logarithm of a weight-average molecular weight of the Polyethylene Standard Reference Material 1475a and not more than a logarithm of a z-average molecular weight of the Polyethylene Standard Reference Material 1475a along the abscissa to derive a slope of a line representing the formula (I-II) as α 0 :
log[η 0 ]=α 0 log M 0 +log K 0 (I-II)
wherein
[η 0 ] represents an intrinsic viscosity (unit: dl/g) of the Polyethylene Standard Reference Material 1475a, M 0 represents an absolute molecular weight of the Polyethylene Standard Reference Material 1475a, and K 0 represents a constant,
provided that in the measurement of the absolute molecular weight and the intrinsic viscosity of each of the polymer and the Polyethylene Standard Reference Material 1475a by using gel permeation chromatography, a mobile phase is ortho-dichlorobenzene and the measurement temperature is 155° C.
6. The resin composition according to claim 1 , wherein a gel fraction is 20 wt % or more, with respect to 100 wt % of a weight of the resin composition.
7. The resin composition according to claim 1 , wherein the thermally conductive material (3) is graphite.
8. A molded article comprising the resin composition according to claim 1 .
9. A laminate comprising:
a heat storage layer (1) comprising the resin composition according to claim 1 ; and
a thermally conductive layer (2) containing a thermally conductive material (3) whose thermal conductivity is 1 W/(m·K) or higher in an amount of 90 wt % or more, with respect to 100 wt % of the total weight of the thermally conductive layer (2).
10. The resin composition according to claim 1 , wherein the thermally conductive material (3) is at least one material selected from the group consisting of metals, low-melting point alloys, metal nitrides, metal carbides, metal carbonates, metal hydroxides, carbon materials, potassium titanate, talc, wollastonite, aluminum oxide, magnesium oxide, beryllium oxide, copper oxide, and copper suboxide.