Patent Description:
Curable compositions have been known for years as suitable for use in a variety of applications that include general-use industrial applications such as adhesives and coatings, as well as high-performance applications in the electronics industry such as e.g. for sealing and bonding electronic components.

With broadened use of curable compositions over the years, performance requirements have become more and more demanding with respect to, in particular, curing profile, adhesion performance, storage stability, handleability and processability characteristics, and compliance with environment and health requirements. When curable compositions are additionally required to provide thermal conductivity, the technical challenge of formulating suitable compositions becomes even more stringent.

Examples of curable compositions provided with thermal conductivity are described in e.g. <CIT>), <CIT>) and <CIT>). The curable compositions described in the art are typically not fully satisfactory for providing good workability and processability in their uncured state (due in particular to unsuitable rheological characteristics), whilst providing excellent thermal conductivity as well as good adhesion and mechanical properties (in particular flexibility) in their fully cured state. <CIT> relates to thermal conductive adhesive based on an acrylate resin, thermal conductive filers, polyphenoxyether as surface active agent and a phosphate compound which is not polymerisable.

Without contesting the technical advantages associated with the partial solutions known in the art, there is still a need for a curable precursor of an adhesive composition which overcomes the above-mentioned deficiencies.

According to one aspect, the present disclosure relates to a curable precursor of an adhesive composition, comprising:.

Also disclosed herein is a curing system suitable for a curable precursor of an adhesive composition comprising a polyether oligomer having a number average molecular weight of at least <NUM>/mol and which comprises at least one free-radical (co)polymerizable reactive group, wherein the curing system comprises a crosslinker comprising at least one acid-functional group derived from phosphoric acid and at least one free-radical (co)polymerizable reactive group.

In still another aspect of the present disclosure, it is provided a method of manufacturing a curable precursor of an adhesive composition, comprising the steps of:.

According to yet another aspect, the present disclosure relates to the use of a curable composition as described above, for industrial applications, in particular for thermal management applications in the automotive industry.

According to a first aspect, the present disclosure relates to a curable precursor of an adhesive composition, comprising:.

In the context of the present disclosure, it has been surprisingly found that a curable precursor as described above is particularly suitable for manufacturing an adhesive composition provided with excellent characteristics and performance as to adhesion, thermal conductivity and mechanical properties (in particular structural strength, flexibility and elasticity) in its fully cured state, whilst the curable precursor provides outstanding characteristics relating to workability and processability (such as e.g. mixing properties, pumpability, flowability, extrudability, applicability, coatability) in its uncured state.

This is a particularly unexpected finding as (meth)acrylate (co)polymer-based curable precursors are generally recognized as leading to challenging viscosity characteristics when used in combination with thermally conductive particulate material. These challenging viscosity characteristics would have been intuitively expected to detrimentally affect not only the workability and processability characteristics of the curable precursor, but also its curing characteristics. The above-detailed finding is all the more surprising as the unique and balanced combination of uncured/cured material properties met by the curable precursor of the present description are somehow self-contradicting.

The curable precursors as described above are further characterized by one or more of the following advantageous benefits: (i) easy and cost-effective manufacturing method, based on readily available starting materials and minimized manufacturing steps; (ii) formulation simplicity and versatility; (iii) ability to efficiently cure without the need for any substantial energy input such as elevated temperature or actinic radiation; (iv) ability to efficiently cure without the need to use volatile adjuvants, in particular water; (v) safe handling due to non-use of material or products having detrimental effects to the human body; (vi) storage and ageing stability; and (vii) ability to use conventional static mixing equipment for dispensing the curable precursor.

Without wishing to be bound by theory, it is believed that these excellent characteristics and performance attributes are due in particular to the presence of a specific combination of: (a) the (meth)acrylate-based (co)polymer base component; (b) the crosslinker for the (meth)acrylate-based (co)polymer base component; (c) the polyether oligomer; and (d) thermally conductive particulate material. Still without wishing to be bound by theory, it is believed that this specific combination of components together contributes to provide the curable precursor with advantageous and unique rheological and thixotropic characteristics, in particular viscosity properties, in combination with excellent curing characteristics, in particular, curing efficiency, curing kinetics and curing profile.

As such, the curable precursor of the present disclosure is outstandingly suitable for thermal management applications in the automotive industry, in particular for the manufacturing of a thermally-conductive gap filler composition which may advantageously be used in the manufacturing of battery modules. Advantageously still, the curable precursor of the disclosure is suitable for automated handling and application, in particular by fast robotic equipment, due in particular to its excellent curing characteristics, mechanical properties (in particular flexibility) and dimensional stability.

In the context of the present disclosure, the expression "thermally-conductive gap filler composition" is meant to designate a thermally-conductive composition that is used to at least partially fill a spatial gap between a first and a second surface. Thermally-conductive gap filler compositions are well known to those skilled in the art.

In the context of the present disclosure, the expression "free-radical curable precursor" is meant to designate a composition which can be cured using an initiator containing or able to produce a free-radical. The term "initiator" is meant to refer to a substance or a group of substances able to start or initiate or contribute to the curing process of the curable precursor.

The terms "glass transition temperature" and "Tg" are used interchangeably and refer to the glass transition temperature of a (co)polymeric material or a mixture. Unless otherwise indicated, glass transition temperature values are estimated by the Fox equation, as detailed hereinafter.

In the context of the present disclosure, the expression "high Tg (meth)acrylic acid ester monomer units" is meant to designate (meth)acrylic acid ester monomer units having a Tg of above <NUM>, as a function of the homopolymer of said high Tg monomers. The expression "low Tg (meth)acrylic acid ester monomer units" is meant to designate (meth)acrylic acid ester monomer units having a Tg of below <NUM>, as a function of the homopolymer of said low Tg monomers.

The term "alkyl" refers to a monovalent group which is a saturated hydrocarbon. The alkyl can be linear, branched, cyclic, or combinations thereof and typically has <NUM> to <NUM> carbon atoms. In one particular aspect, the alkyl group contains <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM> carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, <NUM>-ethylhexyl, <NUM>-octyl and <NUM>-propylheptyl.

The curable precursor of the present disclosure comprises, as a first component, a (meth)acrylate-based (co)polymer base component comprising the free-radical (co)polymerization reaction product of a (co)polymerizable material comprising:.

In a particular aspect of the disclosure, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units are selected from the group consisting of linear or branched C<NUM>-C<NUM> (meth)acrylic acid ester monomer units, C<NUM>-C<NUM> (meth)acrylic acid ester monomer units, or even C<NUM>-C<NUM> (meth)acrylic acid ester monomer units.

In an advantageous aspect, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units for use in the (meth)acrylate-based (co)polymer base component are selected from the group consisting of iso-octyl (meth)acrylate, <NUM>-ethylhexyl (meth)acrylate, <NUM>-propylheptyl (meth)acrylate, butyl (meth)acrylate, and any mixtures thereof.

In a more advantageous aspect, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units are selected from the group consisting of <NUM>-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, and any mixtures thereof.

In another advantageous aspect, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units have no functional groups.

In a typical aspect, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units are different from the optional C<NUM>-C<NUM> methacrylic acid ester monomer units and different from the optional ethylenically unsaturated monomer units having a functional group and which are copolymerizable with monomer units (i) and/or (ii).

In an exemplary aspect, the (meth)acrylate-based (co)polymer base component for use herein comprises the copolymerization reaction product of a copolymerizable material comprising from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. % of the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units, wherein the weight percentages are based on the total weight of the (meth)acrylate-based (co)polymer base component.

According to an advantageous aspect of the disclosure, the (meth)acrylate-based (co)polymer base component for use herein further comprises C<NUM>-C<NUM> methacrylic acid ester monomer units.

Without wishing to be bound by theory, it is believed that the presence of C<NUM>-C<NUM> methacrylic acid ester monomer units in the (meth)acrylate-based (co)polymer base component beneficially impacts its shear strength and cohesion properties.

In one exemplary aspect, the C<NUM>-C<NUM> methacrylic acid ester monomer units for use herein are selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, <NUM>,<NUM>,<NUM>-trimethylcyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate, heptyl methacrylate, cycloheptyl methacrylate, <NUM>-ethyhexyl methacrylate, n-octyl methacrylate, <NUM>-phenoxy ethyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, and any mixtures thereof.

According to an advantageous aspect, the C<NUM>-C<NUM> methacrylic acid ester monomer units for use herein are selected from the group consisting of <NUM>-ethyhexyl methacrylate, isodecyl methacrylate, isotridecanol methacrylate, methacrylic ester <NUM>, ethyltriglycol methacrylate, <NUM>-dimethyl aminoethyl methacrylate, and any mixtures thereof.

According to a more advantageous aspect, the C<NUM>-C<NUM> methacrylic acid ester monomer units for use herein are selected to comprise <NUM>-ethyhexyl methacrylate.

In an exemplary aspect, the (meth)acrylate-based (co)polymer base component for use herein comprises the copolymerization reaction product of a copolymerizable material comprising from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the C<NUM>-C<NUM> methacrylic acid ester monomer units, wherein the weight percentages are based on the total weight of the (meth)acrylate-based (co)polymer base component.

In one advantageous aspect of the present disclosure, the C<NUM>-C<NUM> methacrylic acid ester monomer units for use in the (meth)acrylate-based copolymeric additive herein have no functional groups.

According to one beneficial aspect of the disclosure, the (meth)acrylate-based (co)polymer base component for use herein further comprises ethylenically unsaturated monomer units having a functional group and which are copolymerizable with monomer units (i) and/or (ii).

Without wishing to be bound by theory, it is believed that the presence of ethylenically unsaturated monomer units having a functional group in the (meth)acrylate-based (co)polymer base component beneficially impacts its shear strength and adhesion properties. In some particular aspects of the disclosure, the ethylenically unsaturated monomer units having a functional group are believed to provide advantageous surface interactions with the thermally conductive particulate material, which in turn contribute to provide advantageous rheological profile to the curable precursor of the present disclosure.

In one beneficial aspect of the disclosure, the ethylenically unsaturated monomer units having a functional group and for use herein have a functional group selected from the group consisting of acid, amine, hydroxyl, amide, isocyanate, acid anhydride, epoxide, nitrile, and any combinations thereof.

According to a more beneficial aspect of the disclosure, the ethylenically unsaturated monomer units having a functional group have a functional group selected from the groups of acid groups, in particular carboxylic acids.

According to another beneficial aspect of the disclosure, the ethylenically unsaturated monomer units having a functional group are selected from the group consisting of (meth)acrylic acid, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, <NUM>-hydroxyethyl (meth)acrylate, <NUM>-aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N-vinyl pyrrolidone, N-vinyl caprolactam, (meth)acrylamide, N-vinylacetamide, maleic anhydride, <NUM>-acryloyl morpholine, glycidyl (meth)acrylate, <NUM>-isocyanato ethyl (meth)acrylate, tert-butylamino ethyl (meth)acrylate, acrylonitrile, and any mixtures thereof.

According to particularly beneficial aspect of the disclosure, the ethylenically unsaturated monomer units having a functional group for use herein are selected to comprise acrylic acid.

In an exemplary aspect, the (meth)acrylate-based (co)polymer base component for use herein comprises the copolymerization reaction product of a copolymerizable material comprising from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the ethylenically unsaturated monomer units having a functional group, wherein the weight percentages are based on the total weight of the (meth)acrylate-based (co)polymer base component.

In a typical aspect of the present disclosure, the C<NUM>-C<NUM> (meth)acrylic acid ester monomer units, the C<NUM>-C<NUM> methacrylic acid ester monomer units and the ethylenically unsaturated monomer units having a functional group are mutually self-excluding. Accordingly, any of those monomer unit types cannot qualify as the other monomer unit types.

According to a particular aspect of the curable precursor according to the disclosure, the (meth)acrylate-based (co)polymer base component comprises the copolymerization reaction product of a copolymerizable material comprising:.

wherein the weight percentages are based on the total weight of the (meth)acrylate-based (co)polymer base component.

In an exemplary aspect of the disclosure, the curable precursor comprises from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the (meth)acrylate-based (co)polymer base component, wherein the weight percentages are based on the total weight of the curable precursor.

The curable precursor of the present disclosure further comprises a crosslinker for the (meth)acrylate-based (co)polymer base component, which comprises at least one acid-functional group derived from phosphoric acid and at least one free-radical (co)polymerizable reactive group.

Crosslinkers for use herein are not particularly limited, as long as they fulfill the above-detailed requirements. Suitable crosslinkers for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

Without wishing to be bound by theory, it is believed that the presence of the crosslinker as described above not only provides excellent curing characteristics to the curable precursor (in particular curing efficiency, advantageous curing kinetics and curing profile, and ability to efficiently cure without the need for any substantial energy input such as elevated temperature or actinic radiation), but also beneficially impacts its adhesion properties, due in particular to its excellent surface wetting properties provided in particular by the acid-functional group derived from phosphoric acid. The crosslinker as described above is also believed to provide advantageous surface interactions with the thermally conductive particulate material (in particular, at least partial coating of the conductive particular material), which in turn contribute to provide advantageous rheological properties to the curable precursor of the present disclosure. This particular surface interaction between the crosslinker and thermally conductive particulate material is believed to contribute in preventing, or at least substantially reducing, the sedimentation or settling of the thermally conductive particulate material in the curable precursor. Further, the crosslinker for use herein is also believed to beneficially impact the shear strength and mechanical properties of the fully cured adhesive composition.

In a typical aspect of the disclosure, the crosslinker for use herein is a free-radical crosslinker.

According to one advantageous aspect of the disclosure, the crosslinker for use herein comprises at least two acid-functional groups derived from phosphoric acid.

According to another advantageous aspect of the crosslinker for use herein, the at least one acid-functional group derived from phosphoric acid comprises at least one P-OH group.

In still another advantageous aspect of the crosslinker for use herein, the at least one acid-functional group derived from phosphoric acid is selected from the group consisting of monoesters of phosphoric acid, diesters of phosphoric acid, diesters of diphosphoric acid, and any combinations or mixtures thereof.

In yet another advantageous aspect of the crosslinker for use herein, the at least one acid-functional group derived from phosphoric acid is selected from the group consisting of monoesters of phosphoric acid and C<NUM>-C<NUM> polyol derivatives, diesters of phosphoric acid and C<NUM>-C<NUM> polyol derivatives, diesters of diphosphoric acid and C<NUM>-C<NUM> polyol derivatives, and any combinations or mixtures thereof.

According to one preferred aspect of the disclosure, the crosslinker for use herein comprises at least one acid-functional group derived from phosphoric acid is selected from the group consisting of monoesters of phosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, diesters of phosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, diesters of diphosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, and any combinations or mixtures thereof.

According to another preferred aspect of the disclosure, the crosslinker for use herein comprises at least one acid-functional group derived from phosphoric acid is selected from the group consisting of monoesters of phosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, diesters of phosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, diesters of diphosphoric acid and derivatives of <NUM>,<NUM>-isomer of glycerol, and any combinations or mixtures thereof.

In an advantageous aspect of the disclosure, the crosslinker for the (meth)acrylate-based (co)polymer base component comprises at least two free-radical (co)polymerizable reactive groups.

According to a preferred aspect, the crosslinker for use in the present disclosure comprises at least one free-radical (co)polymerizable reactive group selected from the group consisting of ethylenically unsaturated groups.

In a more preferred aspect of the disclosure, the ethylenically unsaturated groups comprised in the crosslinker are selected from the group consisting of (meth)acrylic groups, vinyl groups, styryl groups, and any combinations or mixtures thereof. More preferably, the ethylenically unsaturated groups are selected from the group consisting of methacrylic groups, acrylic groups, and any combinations or mixtures thereof.

In a particularly preferred aspect of the disclosure, the ethylenically unsaturated groups comprised in the crosslinker are selected from the group of methacrylic groups.

Advantageously, the crosslinker for use herein is an ethylenically unsaturated compound.

According to a particularly preferred aspect, the crosslinker for use in the present disclosure comprises the reaction product(s) of the reaction of phosphoric acid with either <NUM>,<NUM>-glycerol dimethacrylate or <NUM>,<NUM>-glycerol dimethacrylate.

According to another particularly preferred aspect, the crosslinker for use in the present disclosure is selected from the group consisting of <NUM>,<NUM>-glycerol dimethacrylate phosphate monoester, <NUM>,<NUM>-glycerol dimethacrylate phosphate monoester, <NUM>,<NUM>-glycerol dimethacrylate phosphate diester, <NUM>,<NUM>-glycerol dimethacrylate phosphate diester, <NUM>,<NUM>-glycerol dimethacrylate diphosphate diester, <NUM>,<NUM>-glycerol dimethacrylate diphosphate diester, and any mixtures thereof.

In an exemplary aspect, the curable precursor of the present disclosure comprises from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the crosslinker for the (meth)acrylate-based (co)polymer base component, wherein the weight percentages are based on the total weight of the curable precursor.

In an advantageous aspect of the present disclosure, the crosslinker for the (meth)acrylate-based (co)polymer base component is (co)polymerizable with monomer units (i) and/or (ii) and/or (iii) of the (meth)acrylate-based (co)polymer base component.

The curable precursor of the present disclosure further comprises a polyether oligomer having a number average molecular weight of at least <NUM>/mol and which comprises at least one free-radical (co)polymerizable reactive group. Unless otherwise indicated, the number average molecular weight of the polyether oligomer for use herein is determined by conventional gel permeation chromatography (GPC) using appropriate techniques well known to those skilled in the art.

Polyether oligomers for use herein are not particularly limited, as long as they fulfill the above-detailed requirements. Suitable polyether oligomers for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

Without wishing to be bound by theory, it is believed that the polyether oligomer as described above formerly acts as a reactive diluent and rheological modifier for the curable precursor, which contributes to provide the curable precursor with outstanding flexibility characteristics. The polyether oligomer is also believed to beneficially impact the adhesion properties of the curable precursor, due in particular to the beneficial surface wetting properties provided in particular by the oligomeric polyether moiety. The polyether oligomer as described above is also believed to provide advantageous surface interactions with the thermally conductive particulate material, which in turn contribute to enable relatively high loading of thermally conductive particulate material due in particular to the improved compatibility provided between the thermally conductive particulate material and the surrounding (meth)acrylate-based polymeric matrix. Further, the polyether oligomer for use herein is also believed to beneficially impact the shear strength, due in particular to the light crosslinking effect provided by the free-radical (co)polymerizable reactive group(s), and to provide beneficial ageing stability and hydrolytic stability.

In a beneficial aspect of the disclosure, the polyether oligomer having a number average molecular weight of at least <NUM>/mol comprises a (linear) polyether backbone and further comprises at least one free-radical (co)polymerizable reactive group.

In another beneficial aspect of the disclosure, the polyether oligomer for use herein has a number average molecular weight greater than <NUM>/mol, greater than <NUM>/mol, greater than <NUM>/mol, greater than <NUM>/mol, or even greater than <NUM>/mol.

In still another beneficial aspect of the disclosure, the polyether oligomer for use herein has a number average molecular weight greater no greater than <NUM>/mol, no greater than <NUM>/mol, no greater than <NUM>/mol, no greater than <NUM>/mol, or even no greater than <NUM>/mol.

In yet another beneficial aspect of the disclosure, the polyether oligomer for use herein has a number average molecular weight in a range from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol, from <NUM> to <NUM>/mol or even from <NUM> to <NUM>/mol.

According to an advantageous aspect, the polyether oligomer backbone comprised in the polyether oligomer is obtained by copolymerization of tetrahydrofuran units, ethylene oxide units, and optionally propylene oxide units.

In an advantageous aspect, the polyether oligomer for use in the present disclosure comprises at least two free-radical (co)polymerizable reactive groups.

According to another advantageous aspect, the at least one free-radical (co)polymerizable reactive group of the polyether oligomer is selected from the group consisting of ethylenically unsaturated groups.

In a more advantageous aspect of the disclosure, the ethylenically unsaturated groups comprised in the polyether oligomer are selected from the group consisting of (meth)acrylic groups, vinyl groups, styryl groups, and any combinations or mixtures thereof. More preferably, the ethylenically unsaturated groups are selected from the group consisting of methacrylic groups, acrylic groups, and any combinations or mixtures thereof.

In a particularly preferred aspect of the disclosure, the ethylenically unsaturated groups comprised in the polyether oligomer are selected from the group of methacrylic groups.

Advantageously, the polyether oligomer for use herein is an ethylenically unsaturated compound.

According to one advantageous aspect of the curable precursor of the disclosure, the polyether oligomer for use herein has the following formula:
<CHM>
wherein:.

According to another advantageous aspect of the present disclosure, the polyether oligomer for use herein has the following formula:
<CHM>
wherein:.

In one particular aspect, n is selected such that the calculated number average molecular weight is at least <NUM>/mol, at least <NUM>/mol, or even at least <NUM>/mol. In another particular aspect, n is selected such that the calculated number average molecular weight is no greater than <NUM>/mol, no greater than <NUM>/mol, or even no greater than <NUM>/mol. In still another particular aspect, n is selected such that the calculated number average molecular weight is between <NUM> and <NUM>/mol, between <NUM> and <NUM>/mol, or even between <NUM> and <NUM>/mol, where all ranges are inclusive of the end points.

According to still another advantageous aspect of the present disclosure, the polyether oligomer for use herein has the following formula:
<CHM>.

According to yet another advantageous aspect of the present disclosure, the linear polyether oligomer backbone of the polyether oligomer is obtained by copolymerization of tetrahydrofuran units and ethylene oxide units, wherein the mole ratio of these monomer units is in a range from <NUM>:<NUM> to <NUM>:<NUM>, or even from <NUM>:<NUM> to <NUM>:<NUM>.

In an exemplary aspect, the curable precursor of the present disclosure comprises from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the polyether oligomer, wherein the weight percentages are based on the total weight of the curable precursor.

In an advantageous aspect of the present disclosure, the polyether oligomer is (co)polymerizable with monomer units (i) and/or (ii) and/or (iii) of the (meth)acrylate-based (co)polymer base component.

The curable precursor of the present disclosure further comprises a thermally conductive particulate material.

Thermally conductive particulate material for use herein are not particularly limited. Any thermally conductive particulate material commonly known in the art may be used in the context of the present disclosure. Suitable thermally conductive particulate material for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

In a typical aspect of the disclosure, the thermally conductive particulate material for use herein is selected from the group consisting of metal oxides, metal nitrides, metal hydroxides, metallic particles, coated metallic particles, ceramic particles, coated ceramic particles, and any combinations or mixtures thereof.

In an advantageous aspect, the thermally conductive particulate material for use in the disclosure is selected from the group consisting of aluminum oxide, aluminum hydroxide, boron nitride, aluminum nitride, silicon nitride, gallium nitride, silicon oxide, magnesium oxide, zinc oxide, zirconium oxide, tin oxide, copper oxide, chromium oxide, titanium oxide, silicon carbide, graphite, magnesium hydroxide, calcium hydroxide, carbon nanotubes, carbon black, carbon fibers, diamond, clay, aluminosilicate, calcium carbonate, barium titanate, potassium titanate, copper, silver, gold, nickel, aluminum, platinum, and any combinations or mixtures thereof.

According to a more advantageous aspect, the thermally conductive particulate material for use herein is selected from the group consisting of aluminum oxide, aluminum hydroxide, boron nitride, and any combinations or mixtures thereof.

According to a preferred aspect of the disclosure, the thermally conductive particulate material for use herein is selected from the group consisting of aluminum oxide, aluminum hydroxide, and any combinations or mixtures thereof.

In an advantageous aspect, the thermally conductive particulate material for use herein takes a physical form selected from the group of primary particles, primary particle agglomerates, and any combinations or mixtures thereof.

In another advantageous aspect, the thermally conductive primary particles and primary particle agglomerates for use herein have a shape selected from the group consisting of isotropic shapes, anisotropic shapes, and any combinations or mixtures thereof.

In still another advantageous aspect, the thermally conductive primary particles and primary particle agglomerates for use herein have a shape selected from the group consisting of spherical, platelet, and any combinations or mixtures thereof.

According to a yet another advantageous aspect, the thermally conductive particulate material for use herein comprises a mixture of thermally conductive primary particles and primary particle agglomerates having dissimilar shapes and sizes.

Exemplary thermally conductive primary particles and primary particle agglomerates for use herein are described e.g. in <CIT>).

Through-plane thermal conductivity may become most critical in some applications, such as e.g. thermally-conductive filler applications. Therefore, in some aspects, generally symmetrical and isotropic thermally conductive particles (e.g., spherical particles) may be preferred, as asymmetrical fibers, flakes, or plates may tend to align in the in-plane direction;.

According to a particularly advantageous aspect of the curable precursor of the disclosure, the thermally conductive particulate material comprises thermally conductive particles provided with a surface functionalization. Surface functionalization for use herein are not particularly limited. Any surface functionalization commonly known in the art and used in combination with the thermally conductive particulate material may be used in the context of the present disclosure. Suitable thermally conductive particles provided with a surface functionalization for use herein may be easily identified by those skilled in the art in the light of the present disclosure.

In one exemplary aspect of the disclosure, the surface functionalization of the thermally conductive particulate material has a polarity selected from the group consisting of acidic-functional, basic-functional, hydrophobic, hydrophilic, and any combinations or mixtures thereof.

In one advantageous aspect of the disclosure, the surface functionalization of the thermally conductive particulate material comprises hydrophobic surface functionalization.

In the context of the present disclosure, the expression "hydrophobic surface functionalization" is meant to express that the surface of the thermally conductive particulate material, after suitable surface modification, has little or no affinity for polar substances, in particular water. The expression "hydrophilic surface functionalization" is meant to express that the surface of the thermally conductive particulate material, after suitable surface modification, has relatively high affinity for polar substances, in particular water.

According to one advantageous aspect of the disclosure, the surface functionalization of the thermally conductive particles has the same polarity as the functional group of the optionally ethylenically unsaturated monomer units which are copolymerizable with monomer units (i) and/or (ii) of the (meth)acrylate-based (co)polymer base component.

According to another advantageous aspect of the disclosure, the surface functionalization of the thermally conductive particles has a polarity opposite to the functional group of the optionally ethylenically unsaturated monomer units which are copolymerizable with monomer units (i) and/or (ii) of the (meth)acrylate-based (co)polymer base component.

In the context of the present disclosure, it has been surprisingly found that thermally conductive particulate material provided with a surface functionalization provides advantageous surface interactions with, in particular, the optional ethylenically unsaturated monomer units having a functional group, which in turn contribute to provide advantageous rheological profile to the curable precursor of the present disclosure. Without wishing to be bound by theory, it is further believed that thermally conductive particulate material provided with a surface functionalization may additional provide advantageous surface interactions with the crosslinker and/or the polyether oligomer. It is further believed that the surface functionalization, in particular hydrophobic surface functionalization, provides improved dispersion of the thermally conductive particulate material into the of the (meth)acrylate-based (co)polymer base component.

In an advantageous aspect, the thermally conductive particulate material for use herein are further provided with any of flame-retardancy properties, electrical insulation properties, and any combinations thereof.

According to a typical aspect, the curable precursor of the disclosure comprises from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, from <NUM> to <NUM> wt. %, or even from <NUM> to <NUM> wt. %, of the thermally conductive particulate material, wherein the weight percentages are based on the total weight of the curable precursor.

According to another typical aspect of the disclosure, the curable precursor comprises at least <NUM>% by volume, at least <NUM>% by volume, at least <NUM>% by volume, or even at least <NUM>% by volume, of the thermally conductive particulate material, wherein the volume percentages based on the total volume of the curable precursor.

According to still another typical aspect of the disclosure, the curable precursor comprises from <NUM> to <NUM>% by volume, from <NUM> to <NUM>% by volume, from <NUM> to <NUM>% by volume, or even from <NUM> to <NUM>% by volume, of the thermally conductive particulate material, wherein the volume percentages based on the total volume of the curable precursor.

According to yet another typical aspect of the disclosure, the curable precursor further comprises a free-radical polymerization initiator. Exemplary free-radical polymerization initiators for use herein include, but are not limited to, organic peroxides, in particular hydroperoxides, ketone peroxides, and diacyl peroxides.

According to a particular aspect, the curable precursor of the disclosure comprises:.

wherein the weight percentages are based on the total weight of the curable precursor.

According to one advantageous aspect of the disclosure, the curable precursor is (substantially) free of any of plasticizer(s), thixotropic agent(s), silicon-based compounds, halogen-based compounds, isocyanate-based compounds, and any combinations or mixtures thereof.

According to another advantageous aspect of the disclosure, the curable precursor is (substantially) free of solvent(s), in particular organic solvent(s).

In one typical execution, the curable precursor of the present disclosure is in the form of a two-part composition having a first part and a second part, wherein the first part and the second part are kept separated prior to combining the two parts and forming the cured composition.

In an advantageous aspect of the disclosure, the two parts of the curable precursor may be conveniently mixed with a mixing ratio in a range from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, or even from <NUM>:<NUM> to <NUM>:<NUM>.

In a particularly advantageous aspect of the disclosure, the two parts of the curable precursor may be conveniently mixed with a mixing ratio of about <NUM>:<NUM>.

According to an alternative aspect, the curable precursor of the present disclosure is in the form of a one-part adhesive composition.

According to an advantageous aspect, the curable precursor of the disclosure is curable at <NUM> at a curing percentage greater than <NUM>%, greater than <NUM>%, greater than <NUM>%, or even greater than <NUM>%, after a curing time no greater than <NUM> hours, no greater than <NUM> hours, or even no greater than <NUM> hours.

The curing time may be adjusted as desired depending on the targeted applications and manufacturing requirements.

According to another advantageous aspect, the curable precursor is curable without using any actinic radiation, in particular UV light.

According to still another advantageous aspect, the curable precursor is curable without using any additional thermal energy.

In a preferred aspect of the disclosure, the curable precursor is a thermally-conductive gap filler composition.

In the context of the present disclosure, it has been indeed surprisingly discovered that the curable precursor adhesive composition of the present disclosure is outstandingly suitable for thermal management applications, in particular for the manufacturing of a thermally-conductive gap filler composition which may advantageously be used in the manufacturing of battery modules for use in the automotive industry. This is in particular due to the outstanding characteristics and performance as to adhesion, thermal conductivity and mechanical properties (in particular structural strength, flexibility and elasticity) in its fully cured state, and the outstanding characteristics relating to workability and processability (such as e.g. mixing properties, pumpability, flowability, extrudability, applicability, coatability) provided by the curable precursor in its uncured state.

The thermally-conductive gap filler compositions based on the curable composition according to the disclosure are particularly suitable for use in batteries and battery assemblies, specifically the types of batteries used in electric and hybrid electric automobiles. The usefulness of the curable compositions, however, is not so limited. The thermally-conductive gap filler compositions described herein may find use wherever such materials are used, for instance, in electronics (e.g., consumer electronics) applications.

Thermal management plays an important role in many electronics applications. For example, challenges for integrating lithium-ion batteries into electric vehicle battery packs include performance, reliability and safety. Proper thermal management of battery assemblies contributes to addressing each of these challenges. This includes both first level thermal management where battery cells are assembled in a battery module, and second level thermal management where these modules are assembled into battery subunits or battery systems. Thermal management can also be important in the cooling of battery control units, as well as non-battery electronic applications.

Currently, thermal management for battery assemblies relies on curable-liquid gap fillers or pads. The curable liquids flow during assembly and can adjust to dimensional variations before being cured. Also, the liquids can be applied at the time of assembly allowing greater design flexibility. However, the current uncured and cured compositions have several limitations including the presence of contaminants, as discussed below. Pads comprise a pre-determined lay-out of cured material; thus, pads have a reduced tendency to introduce contaminants. However, the cured materials may not provide acceptable conformability to accommodate the range of dimensional variations seen in typical battery assemblies. Also, design changes can be costlier and more complex, as new design lay-outs must be generated.

Liquid thermal gap fillers are typically based on silicones or polyurethanes. Although silicones offer good elastomer properties for this application, they often contain non-functional polymer and volatile residuals from their production processes. Electrical contacts of the battery cell can become contaminated by silicone oil migration. Residuals of volatiles can lead to shrinkage over time. Also, even minute amounts of non-functional polymer can lead to detrimental contamination on metal surfaces inhibiting adhesion of paints or adhesives.

In the context of the present disclosure, it has been unexpectedly found that thermally-conductive gap filler compositions based on the curable precursor of an adhesive composition according to the disclosure may substantially overcome the above-mentioned deficiencies.

In some aspects, thermally-conductive gap filler compositions based on the curable composition according to the disclosure may provide one or more of the following advantageous benefits: (i) easily adjustable cure profile to allow adaption to specific working cycles; (ii) advantageous rheological behavior of the uncured composition; (iii) sufficient open time before cure to allow components to be applied and positioned; (iv) rapid cure after the open time; (v) curing without additional energy input, in particular thermal energy or actinic radiation; (vi) compositions curable without the need for expensive catalysts such as platinum; (vii) advantageous wetting behavior on parts; (viii) stability of the cured composition; (ix) advantageous softness and spring back (recovery on deformation) properties to ensure good contact under use conditions; (x) absence of air inclusions and gas or bubble formation to minimize reduction in thermal conductivity; (xi) absence of contaminants, such as e.g. unreacted components and low molecular weight materials, or volatile components; and (xii) good bonding between sequentially cured layers of the same material.

According to an advantageous aspect, the curable precursor according to the disclosure has a thermal conductivity of at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, at least <NUM> W/mK, or even at least <NUM> W/mK, when measured according to the test method described in the experimental section.

According to another advantageous aspect, the curable precursor has a thermal conductivity in a range from <NUM> to <NUM> W/mK, from <NUM> to <NUM> W/mK, from <NUM> to <NUM> W/mK, from <NUM> to <NUM> W/mK, from <NUM> to <NUM> W/mK, or even from <NUM> to <NUM> W/mK, when measured according to the test method described in the experimental section.

In one beneficial aspect, the curable precursor has an overlap shear strength (OLS) of at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, or even at least <NUM> MPa, when measured according to the test method described in the experimental section.

In another beneficial aspect, the curable precursor has an overlap shear strength (OLS) in a range from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, or even from <NUM> to <NUM> MPa, when measured according to the test method described in the experimental section.

In still another beneficial aspect, the curable precursor has a tensile strength of at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, at least <NUM> MPa, or even at least <NUM> MPa, when measured according to the test method described in the experimental section.

According to yet another beneficial aspect, the curable precursor of the present disclosure has a tensile strength in a range from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, from <NUM> to <NUM> MPa, or even from <NUM> to <NUM> MPa, when measured according to the test method described in the experimental section.

According to another advantageous aspect, the curable precursor has an elongation at break of at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or even at least <NUM>%, when measured according to the test method described in the experimental section.

According to still another advantageous aspect, the curable precursor has a complex viscosity no greater than <NUM> Pa. s, no greater than <NUM> Pa. s, no greater than <NUM> Pa. s, no greater than <NUM> Pa. s, or even no greater than <NUM> Pa. s, when measured according to test method DIN <NUM> at test sequence T4 and under analysis point A4.

According to still another advantageous aspect, the curable precursor has a complex viscosity in a range from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, from <NUM> to <NUM> Pa. s, or even from <NUM> to <NUM> Pa. s, when measured according to test method DIN <NUM> at test sequence T4 and under analysis point A4.

According to still another advantageous aspect, the curable precursor has a dosing speed of at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, or even at least at least <NUM>/s, when measured according to the test method described in the experimental section.

All the particular and preferred aspects relating to, in particular, the (meth)acrylate-based (co)polymer base component, the crosslinker and the polyether oligomer which were described hereinabove in the context of the curable precursor, are fully applicable to the curing system as described above.

According to another aspect, the present disclosure is directed to a battery module comprising a plurality of battery cells connected to a first base plate by a first layer of a first curable precursor as described above.

According to still another aspect, the present disclosure relates to a battery subunit comprising a plurality of battery modules connected to a second base plate by a second layer of a second curable precursor, wherein each battery module comprises a plurality of battery cells connected to a first base plate by a first layer of a curable precursor, wherein the first curable composition and the second curable precursor are independently selected, and wherein each is a curable precursor as described above.

In an advantageous aspect, each of the first and second curable precursor comprised in the battery module or battery subunit as, described above, is a thermally-conductive gap filler composition.

All the particular and preferred aspects relating to, in particular, the (meth)acrylate-based (co)polymer base component, the crosslinker and the polyether oligomer which were described hereinabove in the context of the curable precursor, are fully applicable to the battery module and battery subunit as described above.

Components of a representative battery module during assembly are shown in <FIG>, and the assembled battery module is shown in <FIG>. Battery module <NUM> is formed by positioning a plurality of battery cells <NUM> on first base plate <NUM>. Generally, any known battery cell may be used including, e.g., hard case prismatic cells or pouch cells. The number, dimensions, and positions of the cells associated with a battery module may be adjusted to meet specific design and performance requirements. The constructions and designs of the base plate are well-known, and any base plate (typically metal base plates) suitable for the intended application may be used.

Battery cells <NUM> are connected to first base plate <NUM> through first layer <NUM> of a first curable precursor (in particular a thermally conductive gap filler composition) according to the present disclosure.

First layer <NUM> of the first thermally conductive gap filler provides first level thermal management where the battery cells are assembled in a battery module. As a voltage difference (e.g., a voltage difference of up to <NUM> Volts) is possible between the battery cells and the first base plate, breakthrough voltage may be an important safety feature for this layer. Therefore, in one particular aspect, electrically insulating fillers like ceramics (typically alumina and boron nitride) may be preferred for use in the first thermally conductive gap filler.

In one particular aspect, layer <NUM> may comprise a discrete pattern of the first thermally conductive gap filler applied to first surface <NUM> of first base plate <NUM>, as shown in <FIG>. For example, a pattern of gap filler corresponding to the desired lay-out of the battery cells may be applied, e.g., robotically applied, to the surface of the base plate. The first layer may be formed as a coating of the first thermally conductive gap filler covering all, or substantially all, of the first surface of the first base plate. Alternatively, the first layer may be formed by applying the first thermally conductive gap filler directly to the battery cells and then mounting them to the first surface of the first base plate.

During the assembly step illustrated in <FIG>, the first thermally conductive gap filler is not yet fully cured. This allows the individual battery cells to be positioned and repositioned as needed to achieve the desired layout. The rheological behavior of the not-fully-cured thermally conductive gap filler aides in allowing the gap filler to flow and accommodate the dimensional variations (tolerances) within and between individual battery cells.

In one particular aspect, the gap filler may need to accommodate dimensional variations of up to <NUM>, up to <NUM>, or even more. Therefore, in one particular aspect, the first layer of the first thermally conductive gap filler is at least <NUM> thick, e.g., at least <NUM>, or even at least <NUM> thick. Higher breakthrough voltages may require thicker layers depending on the electrical properties of the gap filler, e.g., in one particular aspect, at least <NUM>, at least <NUM>, or even at least <NUM> thick. Generally, to maximize heat conduction through the gap filler and to minimize cost, the gap filler layer should be as thin as possible, while still ensuring good (thermal) contact with first base plate <NUM>. Therefore, in one particular aspect, the first layer is no greater than <NUM> thick, e.g., no greater than <NUM> thick, or even no greater than <NUM> thick.

In one particular aspect, the thermally-conductive gap filler exhibits shear thinning behavior in its uncured state. This can assist in the uniform application of the gap filler by, e.g., spray, jet, or roll coating. This rheological behavior may aide in allowing the gap filler to be applied using conventional robotic techniques. Shear thinning may also aide in easing the positioning of the individual battery cells by allowing easier movement while still holding the cells in place before final cure is achieved.

As the thermally-conductive gap filler cures, the battery cells are held more firmly in-place. Further, when curing is complete, the battery cells are finally fixed in their desired position, as illustrated in <FIG>. Accordingly, to better automate the manufacturing process, it is important to be able to also predict and control the so-called curing time.

Additional elements, such as bands <NUM> may be used to secure the cells for transport and further handling. Generally, it is desirable for the control cure thermally-conductive gap filler to cure at typical application conditions, e.g., without the need for elevated temperatures or actinic radiation (e.g., ultraviolet light). In one particular aspect, the first thermally conductive gap filler cures at no greater than <NUM>, e.g., no greater than <NUM>, or even no greater than <NUM>.

As shown in <FIG>, a plurality of battery modules <NUM>, such as those illustrated and described with respect to <FIG>, are assembled to form battery subunit <NUM>. The number, dimensions, and positions of the modules associated with a particular battery subunit may be adjusted to meet specific design and performance requirements. The constructions and designs of the second base plate are well-known, and any base plate (typically metal base plates) suitable for the intended application may be used.

Individual battery modules <NUM> are positioned on and connected to second base plate <NUM> through second layer <NUM> of a second thermally conductive gap filler, which may be a control cure thermally-conductive gap filler containing the curing agent described herein.

The second layer <NUM> of a second thermally conductive gap filler is positioned between second surface <NUM> of first base plate <NUM> (see <FIG>) and first surface <NUM> of second base plate <NUM>. The second thermally conductive gap filler provides second level thermal management where the battery modules are assembled into battery subunits. The second thermally conductive gap filler may be a control cure thermally-conductive gap filler. Further, at this level, breakthrough voltage may not be a requirement. Therefore, in one particular aspect, electrically conductive fillers such as graphite and metallic fillers may be used, alone or in combination with electrically insulating fillers like ceramics.

The second layer <NUM> may be formed as a coating of the second thermally conductive gap filler covering all or substantially all of first surface <NUM> of second base plate <NUM>, as shown in <FIG>. Alternatively, the second layer may comprise a discrete pattern of the second thermally conductive gap filler applied to the surface of the second base plate. For example, a pattern of gap filler corresponding to the desired lay-out of the battery modules may be applied, e.g., robotically applied, to the surface of the second base plate. In an alternative aspect, the second layer may be formed by applying the second thermally conductive gap filler directly to second surface <NUM> of first base plate <NUM> (see <FIG>) and then mounting the modules to first surface <NUM> of second base plate <NUM>.

During the assembly step, the second thermally conductive gap filler is not yet fully cured. This allows the individual battery modules to be positioned and repositioned as needed to achieve the desired layout. As the second thermally conductive gap filler continues to cure, the battery modules are held more firmly in-place, until they are finally fixed in their desired position. Thus, it is important to be able to predict and control the so-called pot life and cure times of the gap filler.

The second thermally conductive gap filler may exhibit shear thinning behavior in its uncured (or not fully cured) state. This can assist in the uniform application of the gap filler to the surface of the second base plate by, e.g., spray, jet, or roll coating. This rheological behavior may aide in allowing the gap filler to be applied the surface of the second base plate using conventional robotic techniques or may aide in easing the positioning of the individual battery modules by allowing easier movement while still holding the modules in place before final cure is achieved.

Starting with a liquid, not-fully-cured thermally conductive gap filler also aides in allowing the gap filler to flow and accommodate varying dimensional variations (tolerances) within and between individual battery modules. Therefore, in one particular aspect, the layer of second thermally conductive gap filler is at least <NUM> thick, e.g., at least <NUM>, or even at least <NUM> thick. In one particular aspect, thicker layers may be required to provide the required mechanical strength, e.g., in some particular aspects, at least <NUM>, at least <NUM>, or even at least <NUM> thick. Generally, to maximize heat conduction through the gap filler and to minimize cost, the second layer should be as thin as possible, while still ensure good contact. Therefore, in one particular aspect, the second layer is no greater than <NUM> thick, e.g., no greater than <NUM> thick, or even no greater than <NUM> thick.

The assembled battery subunits may be combined to form further structures. For example, as is known, battery modules may be combined with other elements such as battery control units to form a battery system, e.g., battery systems used in electric vehicles. Additional layers of thermally conductive gap filler according to the present disclosure may be used in the assembly of such battery systems. For example, thermally conductive gap filler according to the present disclosure may be used to mount and help cool the battery control unit.

According to another aspect, the present disclosure is directed to a method of manufacturing a curable precursor of an adhesive composition, comprising the steps of:.

All the particular and preferred aspects relating to, in particular, the (meth)acrylate-based (co)polymer base component, the crosslinker and the polyether oligomer which were described hereinabove in the context of the curable precursor, are fully applicable to the method as described above.

Reproducing the method of manufacturing a curable precursor as described above is well within the capabilities of those skilled in the art reading the present disclosure.

In yet another aspect of the present disclosure, it is provided a method of manufacturing a battery module, which comprises the steps of:.

In yet another aspect, the present disclosure relates to a method of manufacturing a battery subunit, which comprises the steps of:.

According to still another aspect, the present disclosure relates to the use of curable precursor or a cured composition as described above, for industrial applications, in particular for automotive applications, more in particular for thermal management applications in the automotive industry.

According to yet another aspect, the present disclosure relates to the use of curable precursor or a cured composition as described above, for the manufacturing of a thermally-conductive gap filler composition.

In yet another aspect, the present disclosure relates to the use of a curable precursor or a cured composition as described above, for the manufacturing of a battery module comprising a plurality of battery cells, in particular for use in the automotive industry.

Also disclosed herein is the use of a curing system as described above for the manufacturing of a curable composition, in particular comprising a polyether oligomer having a number average molecular weight of at least <NUM>/mol and which comprises at least one free-radical (co)polymerizable reactive group.

Also disclosed herein is the use of a curing system as described above for thermal management applications, in particular in the automotive industry.

Also disclosed herein is the use of a curing system as described above for the manufacturing of a thermally-conductive gap filler composition.

Also disclosed herein is the use of a curing system as described above for the manufacturing of a battery module comprising a plurality of battery cells, in particular for use in the automotive industry.

According to still another aspect, the present disclosure is directed to the use as described above, in combination with a polyether oligomer having a number average molecular weight of at least <NUM>/mol and which comprises at least one free-radical (co)polymerizable reactive group.

The present disclosure is further illustrated by the following examples. These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims.

The curable precursor compositions are prepared from a <NUM>:<NUM> (vol ratio) mixture of two components (Part B and Part A) extruded from a <NUM> cartridge using a static mixer (standard <NUM> gold Quadro nozzle for <NUM> cartridges or SULZER MF <NUM>-<NUM> nozzles for <NUM> cartridges). The preparation of both parts is described hereinafter. Within the open time, the obtained paste is applied to the surface of the test panel as a film having a thickness of about <NUM>. The surface of test samples for the overlap shear strength test (aluminum, grade EN AW2024T3) are sandblasted before bonding using pure corundum with a grain size of about <NUM> micrometers. The test samples are left at ambient room temperature (<NUM> +/- <NUM>, <NUM>% relative humidity +/-<NUM>%) for <NUM> days and then placed into an air circulating oven for <NUM> minutes at <NUM> prior to testing and the various performance testing are measured as described below.

The samples are prepared as described previously, at the exception that the test samples are - prior to testing - previously submitted to cyclic climatic ageing procedure according PR308. <NUM> (BMW). After appropriate ageing, the test samples are reconditioned in a constant climate room for <NUM> hours and the performance is measured as described above.

The thermal conductivity of the cured compositions is measured at <NUM> with Laser Flash Analysis (LFA) using Light Flash Apparatus LFA <NUM> HyperFlash®, commercially available from Netzsch GmbH, Germany, on samples having a thickness of <NUM>.

Overlap shear strength is determined according to DIN EN <NUM> using a Zwick Z050 tensile tester (commercially available by Zwick GmbH & Co. KG, Ulm, Germany) operating at a cross head speed of <NUM>/min. For the preparation of an overlap shear strength test assembly, the paste resulting from the mixing of Part A and Part B is spackled onto one surface of a test panel. The aluminum EN AW2024T3 test panels are sandblasted before bonding. Afterwards, the sample is covered by a second aluminum strip forming an overlap joint of <NUM>. Hereby, the use of glass beads having a selected diameter distribution ensured formation of a bond line having a thickness of about <NUM> micrometers. The overlap joints are then clamped together using two binder clips and the test assemblies are further stored at room temperature for <NUM> days after bonding, and then placed into an air circulating oven for <NUM> minutes at <NUM>. The samples are either tested directly at room temperature or undergo ageing and are tested thereafter. Five samples are measured for each of the examples and results averaged and reported in MPa.

Tensile measurements (tensile strength and elongation at break) are carried out according to DIN ISO <NUM>-<NUM>-5A using a Zwick Z050 tensile tester (commercially available by Zwick GmbH & Co. KG, Ulm, Germany) operating at a cross head speed of <NUM>/min. Films having a thickness of about <NUM> are prepared according to the procedure described above. Five samples having a dog bone shape are stamped according to the geometry of DIN ISO <NUM>-<NUM>-5A and used for further mechanical testing. Measurements are done for each of the samples and the results are averaged and reported in MPa for the tensile strength and in percentage for the elongation at break.

Complex viscosity of the test samples is measured at <NUM> according to DIN <NUM><NUM> at test sequence T4 and under analysis point A4 with Anton Paar rheometer MCR <NUM> using RheoCompass software from Anton Paar. Analysis mode A4 describes the complex viscosity under high deformation and high frequency. <FIG> provides a graphical overview of the various test sequences (T) and analysis points (A) of Test Method DIN EN <NUM><NUM>.

Dosing speed of the test samples is measured by dispensing the sample with dispenser ViscoDuo-VM <NUM>/<NUM> and dosed with <NUM>-control ViscoDos4000T-<NUM>-Touch (commercially available from ViscoTec GmbH, Germany). The dosing speed is measured by using a rotor rotation of about <NUM> rpm and a dosing pressure of <NUM> bar.

In the examples, the following raw materials are used:.

The exemplary <NUM>-component (Part A and Part B) curable compositions according to the present disclosure are prepared separately by combining the ingredients from the list of materials of Table <NUM> in a high-speed mixer (DAC <NUM> FVZ Speedmixer, available from Hauschild Engineering, Germany) stirring at <NUM> rpm for <NUM> minutes until a homogeneous mixture is achieved. The material is then slightly degassed to avoid entrapped air. The acrylic acid ester monomer units, the polyether oligomer and the crosslinker are added first, followed by the various thermally conductive particulate material in successive steps. The free-radical polymerization initiator and the crosslinker are present solely in Part B, while the amine-based free-radical polymerization accelerator is present solely in Part A. During the mixing, the temperature of the mixing shall not exceed <NUM>.

Afterwards, the two parts are filled into a <NUM>:<NUM> (vol ratio) <NUM> cartridge and the mixture applied to the surface of the test panel as described above. In Table <NUM>, all concentrations are given as wt. Comparative example CE1 does not comprise any crosslinker. Comparative example CE2 does not comprise any polyether oligomer.

As can be seen from the results shown in Table <NUM>, the thermally-conductive gap filler compositions according to the present disclosure provide excellent performance and characteristics as to mechanical properties and thermal conductivity. In contrast, the composition of comparative example CE1 (not according to the disclosure) is deficient at least in terms of OLS strength and tensile strength.

The mechanical performance of various compositions is also tested upon cyclic climatic ageing procedure according PR308. <NUM> (BMW).

As can be seen from the results shown in Table <NUM>, the thermally-conductive gap filler compositions according to the present disclosure provide even improved OLS and tensile strength performance upon ageing conditions. As expected though, the elongation at break performance (elasticity) is slightly reduced upon ageing.

The complex viscosity of Parts B of various compositions is also measured according to the procedure described above.

As can be seen from the results shown in Table <NUM>, the thermally-conductive gap filler compositions according to the present disclosure provide excellent viscosity characteristics which translate into excellent pumpability characteristics. In contrast, the composition of comparative example CE2 (not according to the disclosure) provides very low complex viscosity which makes it unsuitable in regular pumping conditions.

The dosing speed of the composition of Ex. <NUM> is also measured according to the procedure described above.

Claim 1:
A curable precursor of an adhesive composition, comprising:
a) a (meth)acrylate-based (co)polymer base component comprising the free-radical (co)polymerization reaction product of a (co)polymerizable material comprising:
i. C<NUM>-C<NUM> acrylic acid ester monomer units;
ii. optionally, C<NUM>-C<NUM> methacrylic acid ester monomer units; and
iii. optionally, ethylenically unsaturated monomer units having a functional group and which are copolymerizable with monomer units (i) and/or (ii);
b) a crosslinker for the (meth)acrylate-based (co)polymer base component, which comprises at least one acid-functional group derived from phosphoric acid and at least one free-radical (co)polymerizable reactive group;
c) a polyether oligomer having a number average molecular weight of at least <NUM>/mol (determined by conventional gel permeation chromatography GPC) and which comprises at least one free-radical (co)polymerizable reactive group; and
d) a thermally conductive particulate material.