Thermally conductive curable composition
A moisture-curable composition, including between 0.6 and 15.0 wt.-% of at least one organic polymer containing reactive silane groups, between 70 and 95 wt.-% of at least one filler, at least one dispersion additive, optionally at least one catalyst for the curing of silane-functional polymers and up to 10 wt.-% of at least one plasticizer, characterized in that said filler is selected from the list consisting of aluminium oxide, aluminium hydroxide, boron nitride, aluminium nitride, zinc oxide, silver, copper, aluminium, chalk, aluminosilicate, graphite, and any mixture of these fillers; with the proviso that the amount of chalk in the filler does not exceed 25 wt.-% of the total amount of filler. The moisture-curable composition shows excellent thermal conductivity and is particularly suitable as adhesive, gap filler, or sealant suitable for e-coat applications and battery bonding especially in electric automobile assembly.
1 . A moisture-curable composition, consisting of two individual components A and B that are stored in separated containers and mixed before or during applications to yield the moisture-curable composition,
wherein the component A comprises, based on component A:
between 1.2 and 9.0 wt.-% of at least one organic polymer P containing reactive silane groups, wherein the organic polymer P containing reactive silane groups is a polyurethane containing reactive silane groups or a polyether containing reactive silane groups or a mixed form of these polymers;
between 0.3 and 2.0 wt.-% of at least one organosilane or oligomers thereof;
between 80 and 93 wt.-% of at least one filler F;
between 1 and 3 wt.-% at least one dispersion additive D;
between 4 and 10 wt.-% of at least one plasticizer PL;
the component B comprises, based on component B,
between 3 and 10 wt.-% of the plasticizer PL;
between 85 and 95 wt.-% of the at least one filler F;
between 1 and 3 wt.-% of the dispersion agent D;
between 0.5 and 2.5 wt.-% of water;
between 0 and 1.5 wt.-% of a catalyst for the curing of silane-functional polymers;
wherein
the filler F is selected from the group consisting of aluminium oxide, aluminium hydroxide, boron nitride, aluminium nitride, zinc oxide, and any mixture of these fillers; with the proviso that the amount of chalk in the filler F does not exceed 25 wt.-% of the total amount of filler F; and
wherein
the composition does not contain polydiorganosiloxanes.
2 . The moisture-curable composition as claimed in claim 1 , wherein the filler F comprises aluminium oxide and aluminium hydroxide.
3 . The moisture-curable composition as claimed in claim 1 , wherein the dispersion additive D is an amine or ammonium salt of a polymer or copolymer containing carboxylate and/or phosphate groups.
4 . The moisture-curable composition as claimed in claim 1 , wherein the plasticizer PL comprises a trialkyl and/or triaryl phosphate.
5 . The moisture-curable composition as claimed in claim 1 , wherein the polymer P has end groups of the formula (VIII)
wherein
R 16 is a linear or branched divalent hydrocarbyl radical having 1 to 12 carbon atoms;
T is a divalent radical selected from —O—, —S—, —N(R 17 )—, —O—CO—N(R 17 )—, —N(R 17 )—CO—O— and —N(R 17 )—CO—N(R 17 )—,
where R 17 is a hydrogen radical or a linear or branched hydrocarbyl radical which has 1 to 20 carbon atoms;
R 14 is a methyl or ethyl radical;
R 15 is a methyl radical; and
x is 0 or 1.
6 . The moisture-curable composition as claimed in claim 1 , wherein the organosilane comprises an organosilane of the formula (I)
wherein
R 20 independently stands for a monovalent hydrocarbyl or heterocarbyl radical, which contains 1 to 12 carbon atoms and wherein the carbon atom next to the silicon atom either bonds via a C═C double bond to another carbon atom or bonds to a heteroatom selected from O, N, and S;
R 21 independently stands for a linear, cyclic, or branched divalent hydrocarbyl radical having 2 to 12 carbon atoms; and
R 22 stands for a hydrogen atom or a group of the formula (Ia)
7 . A method, comprising
adhesively bonding, coating, or sealing substrates with the moisture curable composition according to claim 1 .
8 . The method according to claim 7 , wherein at least one of the substrates is a battery or an electronic device.
9 . The moisture-curable composition as claimed in claim 1 , wherein the organic polymer P containing reactive silane groups is a polyether containing reactive silane groups.
10 . The moisture curable composition as claimed in claim 1 , wherein said composition possesses thermal conductivity of ≥2 W/mK measured according to ASTM D5470.
11 . The moisture-curable composition as claimed in claim 1 , wherein the organic polymer P containing reactive silane groups consists of a polyurethane containing reactive silane groups or a polyether containing reactive silane groups or a mixed form of these polymers.
12 . The moisture-curable composition as claimed in claim 1 , wherein the amount of chalk in the filler F does not exceed 15 wt.-% of the total amount of filler F.
13 . The moisture-curable composition as claimed in claim 1 , wherein the amount of chalk in the filler F does not exceed 10 wt.-% of the total amount of filler F.
14 . The moisture-curable composition as claimed in claim 1 , wherein no chalk is contained in the filler F.