Curing precursor of adhesive composition

Abstract

The present disclosure relates to a curable precursor of an adhesive composition, the curable precursor comprising: (a) a radically (co)polymerizable (meth)acrylate-based component, (I C 1 ~C 32 (meth)acrylic acid ester monomer; (ii) a radical (co)polymerizable (meth)acrylate-based component comprising an ethylenically unsaturated acidic compound; (b) a crosslinker for the (meth)acrylate based component, comprising at least one acid functional group derived from phosphoric acid and at least one radically (co)polymerizable reactive group; (c) a nitroxide, C 1 ~C 32 The present invention relates to a curable precursor, wherein the (meth)acrylic acid ester monomer (a)(i) does not contain any functional group other than a (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acid functional group derived from phosphoric acid. The present disclosure further relates to methods for producing cured compositions from the curable precursors and to the use of the curable precursors for adhesive and / or thermal management applications in the automotive industry.

Description

[Technical Field]

[0001] This disclosure relates to a curable precursor for an adhesive composition containing a radical (co)polymerizable (meth)acrylate component. [Background technology]

[0002] Curable compositions have long been known as suitable for a wide range of applications, including general industrial uses such as adhesives and coatings, as well as high-performance applications in the electronics industry, such as sealing and joining electronic components. Due to the extensive use of curable compositions over many years, performance requirements have become increasingly stringent, particularly regarding curing profile, adhesive performance, storage stability, handling and processability, and compliance with environmental and health requirements. When curable compositions are further required to provide thermal conductivity, formulating a suitable composition becomes even more challenging.

[0003] During storage of acrylic curable compositions, self-polymerization can occur, and inhibitors are typically used to prevent it. Most inhibitors require oxygen to ensure their functionality. Highly viscous, highly packed adhesive acrylic compositions, such as acrylic temperature control compositions, and other adhesive acrylic curable compositions, exhibit limited oxygen diffusion. As a result, core polymerization can occur, particularly during the storage of large quantities of highly packed acrylic compositions, for example, when the curable composition is stored in a drum with a volume of 100 or 200 liters. During storage of the curable composition in the drum, oxygen is consumed by the inhibitor, but because the diffusion of oxygen into the core region of the drum is limited, sufficient oxygen becomes unavailable in the core region over time to ensure the proper functionality of the inhibitor, resulting in core polymerization.

[0004] In adhesive acrylic compositions, acids can increase adhesive strength. Acids are highly reactive and tend to destabilize compositions, leading to a higher tendency for core polymerization. Therefore, the presence of acids such as acrylic acid in acrylic curable compositions makes it more difficult to stabilize the curable composition for storage.

[0005] International Publication No. 2019 / 040596(A1) discloses a combination of inhibitors for increasing the shelf life of a urethane (meth)acrylate composition. The resin composition of International Publication No. 2019 / 040596(A1) comprises a urethane (meth)acrylate and an inhibitor package comprising at least one nitroxide radical and at least one base, the base being selected from the group consisting of tertiary amine bases, quaternary ammonium hydroxides, alkoxides, or hydroxides. If the base is not added to the nitroxide, or if an acid is added to the composition, a significantly reduced shelf life occurs.

[0006] In particular, when the curable precursor contains an acrylic acid monomer, there is still a need for a curable precursor for adhesive acrylic compositions that has good storage stability and can be cured at room temperature.

[0007] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are interchangeable. The term “including” also includes the terms “essentially consisting of” and “consisting of.” [Overview of the project]

[0008] In a first aspect, the present disclosure relates to a curable precursor for an adhesive composition, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (i) C1~C 32 (meth)acrylic acid ester monomer and (ii) Ethylene unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for (meth)acrylate components comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, Includes, C1~C 32The present invention relates to a curable precursor, wherein (meth)acrylic acid ester monomer (a)(i) contains no functional groups other than (meth)acrylic acid ester groups, and ethylenically unsaturated acidic compound (a)(ii) contains no acid functional groups derived from phosphoric acid.

[0009] In another aspect, the present disclosure also provides a method for producing a cured composition from the curable precursor disclosed herein, wherein the method comprises: providing a curable precursor, wherein the curable precursor comprises: (a) a radical (co)polymerizable (meth)acrylate component, wherein (i) C1 to C 32 (meth)acrylic acid ester monomer, and (ii) an ethylenically unsaturated acidic compound, and a radical (co)polymerizable (meth)acrylate component comprising (b) a crosslinking agent for the (meth)acrylate component, which comprises at least one acid functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, and (c) a nitroxide, and comprising, C1 to C 32 providing the curable precursor, wherein (meth)acrylic acid ester monomer (a)(i) contains no functional groups other than (meth)acrylic acid ester groups, and ethylenically unsaturated acidic compound (a)(ii) contains no acid functional groups derived from phosphoric acid; providing an initiator for radical polymerization of the curable precursor; mixing the curable precursor and the initiator; and curing the mixture of the curable precursor and the initiator, the method comprising.

[0010] In still another aspect, the present disclosure relates to use of the curable precursor disclosed herein for an adhesive application and / or a heat management application in the automotive industry.

[0011] The curable precursors disclosed herein have good storage stability and a tendency towards low core polymerization during storage. The curable precursors disclosed herein can be stored in 100 or 200 liter drums for several months. In some embodiments of this disclosure, the curable precursors are highly packed thermally conductive curable precursors, and even these highly packed curable precursors, which have low oxygen diffusion, have good storage stability and a tendency towards low core polymerization during storage.

[0012] Although the curable precursors disclosed herein are stabilized for storage, rapid curing at room temperature is still possible due to the small amount of nitroxide inhibitor required to prevent core polymerization. The properties of the cured product, namely hardness, overlap shear strength, elongation at fracture, and thermal conductivity, are not adversely affected.

[0013] Surprisingly, it has been found that small amounts of nitroxide can effectively prevent core polymerization in acrylic compositions containing acids such as acrylic acid or other polymerizable monomers having acidic functional groups. Those skilled in the art would have anticipated that nitroxide cannot be used if acids, particularly acrylic acid, are present in the curable composition. They would also have anticipated that nitroxide can only be used as an inhibitor in a basic environment and that the absence of acidic components may be required. [Modes for carrying out the invention]

[0014] A curable precursor for an adhesive composition, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (i) C1~C 32 (meth)acrylic acid ester monomer and (ii) Ethylene unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) a crosslinking agent for (meth)acrylate components, which comprises at least one acid functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) a nitroxide, comprising C1 to C 32 Disclosed herein is a curable precursor, wherein the (meth)acrylic acid ester monomer (a)(i) contains no functional groups other than (meth)acrylic acid ester groups, and the ethylenically unsaturated acidic compound (a)(ii) contains no acid functional group derived from phosphoric acid.

[0015] The term "curable precursor" is intended to refer to a composition that can be cured using an initiator. The term "initiator" is intended to refer to a substance or group of substances capable of initiating, starting or contributing to the curing process of the curable precursor.

[0016] The term "radical (co)polymerizable component" is intended to refer to a composition that can be cured using an initiator that contains or is capable of generating free radicals. The radical (co)polymerizable component may contain only one, two, or three or more radical (co)polymerizable groups. Typical examples of radical (co)polymerizable groups include unsaturated carbon groups such as the vinyl group present in, for example, (meth)acrylate groups.

[0017] As used herein, "(meth)acrylic" is an abbreviation referring to "acrylic" and / or "methacrylic". For example, "(meth)acrylate-based component" refers to "acrylate-based component" and / or "methacrylate-based component", and "C1 to C 32 (meth)acrylic acid ester monomer" refers to "C1 to C 32 acrylic acid ester monomer" and / or "C1 to C 32 methacrylic acid ester monomer".

[0018] As used herein, "(co)polymerizable" is an abbreviation referring to "polymerizable" and / or "copolymerizable".

[0019] A "monomer" is any chemical substance that can be characterized by a chemical formula having a radical (co)polymerizable unsaturated group (including a (meth)acrylate group) that can be polymerized to form an oligomer or polymer, thereby increasing its molecular weight. Typically, the molecular weight of a monomer can be simply calculated based on the given chemical formula.

[0020] The curable precursors of the adhesive compositions disclosed herein include (a) radical (co)polymerizable (meth)acrylate components, i.e., radical (co)polymerizable acrylate components or radical (co)polymerizable methacrylate components or combinations thereof.

[0021] Radical (co)polymerizable (meth)acrylate components include (i) C1-C 32 (meth)acrylic acid ester monomers, i.e., C1-C 32 Acrylic acid ester monomer, or C1-C 32 Contains methacrylate monomers or combinations thereof. C1-C 32 (meth)acrylic acid ester monomers are linear or branched C1-C11 monomers. 32 It may be a (meth)acrylic acid ester monomer. Preferably, the radical (co)polymerizable (meth)acrylate component is C1-C 32 Contains acrylic acid ester monomers.

[0022] C1-C for use in radical (co)polymerizable (meth)acrylate components 32 The (meth)acrylic acid ester monomer may be selected from the group consisting of isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, methyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and any mixture thereof.

[0023] C1~C 32(Meth)acrylic acid ester monomers do not contain any functional groups other than the (meth)acrylic acid ester group.

[0024] The curing precursor is 1-50% by weight, 1-30% by weight, 1-20% by weight, 2-15% by weight, or 3-10% by weight of C1-C 32 It may contain (meth)acrylic acid ester monomers, and the weight percentage is based on the total weight of the curable precursor.

[0025] The radical (co)polymerizable (meth)acrylate component further comprises (ii) an ethylenically unsaturated acidic compound.

[0026] "Ethylene-unsaturated acidic compounds" are intended to include monomers, oligomers, and polymers that are ethylenically unsaturated and have acid and / or acid precursor functionalities.

[0027] Acidic precursor functionalities include, for example, anhydrides such as -CO-O-CO- and acid halides.

[0028] The acidic group preferably includes one or more carboxylic acid residues such as -COOH, or a sulfonic acid residue such as -SO3H.

[0029] The terms "polymer" or "polymer material" are used interchangeably and refer to homopolymers, copolymers, terpolymers, etc.

[0030] Specific examples of ethylenically unsaturated acidic compounds include, but are not limited to, di or tri(meth)acrylated citric acid, poly(meth)acrylated oligomaleic acid, poly(meth)acrylated polymaleic acid, poly(meth)acrylated poly(meth)acrylic acid, poly(meth)acrylated polysulfonate, and poly(meth)acrylated polyboric acid.

[0031] (Meth)acrylic acid and alkanediols (for example, C2-C 20 , or C2~C 12 , or C6~C 10The reaction products with ) and the reaction products with phosphorus oxide were also found to be suitable.

[0032] Furthermore, monomers, oligomers, and polymers of unsaturated carboxylic acids such as (meth)acrylic acid and aromatic (meth)acrylic acid (e.g., methacrylated trimellitic acid), as well as their anhydrides, can also be used. In some embodiments, acrylic acid or methacrylic acid is used as the ethylenically unsaturated acidic compound (ii).

[0033] Ethylene-unsaturated acidic compounds (a) and (ii) do not contain acidic functional groups derived from phosphoric acid.

[0034] "Acid functional groups derived from phosphoric acid" means that the acid functional group includes a P-OH group. In other words, "ethylenically unsaturated acidic compounds (a) and (ii) do not contain acid functional groups derived from phosphoric acid" means that ethylenically unsaturated acidic compounds (a) and (ii) do not contain a P-OH group.

[0035] The curable precursor may contain 0.1-20% by weight, 0.1-10% by weight, 0.1-5% by weight, 0.1-3% by weight, 0.1-2% by weight, 0.2-2% by weight, or 0.2-1% by weight of an ethylenically unsaturated acidic compound, the weight percentage being based on the total weight of the curable precursor.

[0036] The curable precursor may contain 1-50% by weight, 1-30% by weight, 1-20% by weight, or 10-15% by weight of (meth)acrylate components, the weight percentage being based on the total weight of the curable precursor.

[0037] The curable precursor of the adhesive composition further comprises (b) a crosslinking agent for a (meth)acrylate component, which comprises at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group.

[0038] The crosslinking agent for (meth)acrylate components comprises at least one acidic functional group derived from phosphoric acid. The crosslinking agent for (meth)acrylate components may also comprise at least two acidic functional groups derived from phosphoric acid.

[0039] At least one acidic functional group derived from the crosslinking agent phosphoric acid may include at least one P-OH group.

[0040] The at least one acidic functional group derived from the crosslinking agent phosphoric acid may be selected from the group consisting of phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid triesters, diphosphate esters, diphosphate diesters, and any combination or mixture thereof.

[0041] The at least one acidic functional group derived from the crosslinking agent phosphoric acid may be selected from the group consisting of monoesters of phosphoric acid and C1-C6 polyol derivatives, diesters of phosphoric acid and C1-C6 polyol derivatives, triesters of phosphoric acid and C1-C6 polyol derivatives, esters of diphosphate and C1-C6 polyol derivatives, diesters of diphosphate and C1-C6 polyol derivatives, and any combination or mixture thereof.

[0042] According to a preferred embodiment of the present invention, at least one acidic functional group derived from the crosslinking agent phosphoric acid is selected from the group consisting of monoesters of phosphoric acid and 1,3-isomer derivatives of glycerol, diesters of phosphoric acid and 1,3-isomer derivatives of glycerol, diesters of diphosphate and 1,3-isomer derivatives of glycerol, and any combination or mixture thereof.

[0043] According to another preferred embodiment of the present invention, at least one acidic functional group derived from the crosslinking agent phosphoric acid is selected from the group consisting of monoesters of phosphoric acid and 1,2-isomer derivatives of glycerol, diesters of phosphoric acid and 1,2-isomer derivatives of glycerol, diesters of diphosphate and 1,2-isomer derivatives of glycerol, and any combination or mixture thereof.

[0044] The crosslinking agent for the (meth)acrylate component contains at least one radical (co)polymerizable reactive group.

[0045] The crosslinking agent for the (meth)acrylate component may contain at least two radical (co)polymerizable reactive groups.

[0046] In preferred embodiments of the present disclosure, the crosslinking agent comprises at least one radical (co)polymerizable reactive group selected from the group consisting of ethylenically unsaturated groups.

[0047] In a more preferred embodiment of the present disclosure, the ethylenically unsaturated group contained in the crosslinking agent is selected from the group consisting of (meth)acrylic groups, vinyl groups, styryl groups, and any combination or mixture thereof. More preferably, the ethylenically unsaturated group is selected from the group consisting of methacrylic groups, acrylic groups, and any combination or mixture thereof.

[0048] In a particularly preferred embodiment of this disclosure, the ethylenically unsaturated group contained in the crosslinking agent is selected from the group of methacrylic groups.

[0049] Advantageously, the crosslinking agents used herein are ethylenically unsaturated compounds.

[0050] In a particularly preferred embodiment, the crosslinking agent for use in the present disclosure comprises a reaction product of the reaction of phosphoric acid with either 1,3-glycerol dimethacrylate or 1,2-glycerol dimethacrylate.

[0051] In another particularly preferred embodiment, the crosslinking agent for use in the present disclosure is selected from the group consisting of 1,3-glycerol dimethacrylate phosphate monoester, 1,2-glycerol dimethacrylate phosphate monoester, 1,3-glycerol dimethacrylate phosphate diester, 1,2-glycerol dimethacrylate phosphate diester, 1,3-glycerol dimethacrylate diphosphate diester, 1,2-glycerol dimethacrylate diphosphate diester, and any mixture thereof.

[0052] In an advantageous aspect of this disclosure, the crosslinking agent for the (meth)acrylate component is (co)polymerizable with monomer (i) and / or (ii) of the (meth)acrylate component.

[0053] In some embodiments, the crosslinking agent (b) may further function as an adhesion promoter.

[0054] The curable precursor of this disclosure may contain crosslinking agents for (meth)acrylate components in amounts of 0.01 to 10% by weight, 0.01 to 8% by weight, 0.05 to 6% by weight, 0.05 to 5% by weight, 0.05 to 4% by weight, 0.1 to 2% by weight, or even 0.1 to 1% by weight, the weight percentages being based on the total weight of the curable precursor.

[0055] The curable precursors disclosed herein further comprise nitroxides, which are free radicals containing an R2N-O· functional group. They are sometimes referred to as nitroxyl radicals or aminooxyl radicals.

[0056] Nitroxides function as inhibitors of the curable precursors disclosed herein. Surprisingly, nitroxides have inhibitory properties and can effectively prevent core polymerization despite the presence of acidic compounds in the curable precursor. The acidic compounds are included as ethylenically unsaturated acidic compounds in the radical (co)polymerizable (meth)acrylate components of the curable precursor, and as at least one acidic functional group derived from phosphoric acid in the crosslinking agent for the (meth)acrylate components. Those skilled in the art would have anticipated that nitroxides cannot act as inhibitors in an acidic environment, and that the addition of a base and a basic environment may be necessary for nitroxides to act as inhibitors.

[0057] The nitroxide can be selected from the group consisting of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), its derivatives, and combinations thereof.

[0058] Nitroxides include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4-hydroxy-TEMPO, TEMPOL), 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO), 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (4-oxo-TEMPO), 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl acetate, 1-oxyl-2,2, 6,6-tetramethylpiperidine-4-yl 2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl 4-tert-butylbenzoate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) succinate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) adipate, Bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) sebacate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) n-butyl malonate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) phthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) isophthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) hexahydroterephthalate, N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) adipamine, The following may be selected from the group consisting of N-1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl-dodecylsuccinimide, 1-oxyl-4-methoxy-2,2,6,6-tetramethylpiperidine, 1-oxyl-4-amino-2,2,6,6-tetramethylpiperidine, and 1-oxyl-4-acetamino-2,2,6,6-tetramethylpiperidine.

[0059] Preferably, the nitroxide is 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4-hydroxy-TEMPO,TEMPOL).

[0060] The curable precursor may contain at least 0.001% by weight, or at least 0.002% by weight, or at least 0.003% by weight of nitroxide, based on the total weight of the curable precursor.

[0061] The curable precursor may contain up to 0.1% by weight, or up to 0.05% by weight, or up to 0.02% by weight, or up to 0.01% by weight, or up to 0.008% by weight, or up to 0.006% by weight, or up to 0.005% by weight of nitroxide, based on the total weight of the curable precursor.

[0062] The curable precursor is calculated based on the total weight of the curable precursor in the following proportions: 0.001-0.1% by weight, or 0.001-0.05% by weight, or 0.001-0.02% by weight, or 0.001-0.01% by weight, or 0.001-0.008% by weight, or 0.002-0.1% by weight, or 0.002-0.05% by weight, or 0.002-0.02% by weight, or 0.002-0.01% by weight, or 0.002- It may contain 0.008% by weight, or 0.002-0.004% by weight, or 0.003-0.1% by weight, or 0.003-0.05% by weight, or 0.003-0.02% by weight, or 0.003-0.01% by weight, or 0.003-0.008% by weight, or 0.003-0.006% by weight, or 0.003-0.005% by weight, or less than 0.003-0.005% by weight of nitroxide.

[0063] The curable precursors disclosed herein may further comprise (d) a polyether oligomer having a number-average molecular weight of at least 2000 g / mol and containing at least one radical (co)polymerizable reactive group.

[0064] Unless otherwise indicated, the number-average molecular weight of polyether oligomers used herein is determined by conventional gel permeation chromatography (GPC) using appropriate techniques well known to those skilled in the art.

[0065] While we do not wish to be bound by theory, the above-mentioned polyether oligomers are thought to act as reactive diluents and rheological modifiers for curable precursors, contributing to providing the curable precursors with remarkable flexibility. Polyether oligomers are also thought to have a beneficial effect on the adhesion properties of the curable precursors, particularly due to the beneficial surface wetting properties provided especially by the oligomer polyether moiety. In the case of curable precursors containing thermally conductive particles, the above-mentioned polyether oligomers are also thought to provide favorable surface interactions with the thermally conductive particles, which contribute to enabling relatively high packing of thermally conductive particles, particularly due to the improved fit provided between the thermally conductive particles and the surrounding (meth)acrylate polymer matrix. Furthermore, polyether oligomers for use herein are also thought to have a beneficial effect on shear strength, providing aging stability and hydrolysis stability, particularly due to the photocrosslinking effect provided by the radical (co)polymerizable reactive groups.

[0066] A polyether oligomer having a number-average molecular weight of at least 2000 g / mol and containing at least one radical (co)polymerizable reactive group may also contain a (linear) polyether skeleton. The polyether oligomer skeleton contained in the polyether oligomer can be obtained by copolymerization of tetrahydrofuran units, ethylene oxide units, and optionally propylene oxide units. The molar ratio of these monomers may be in the range of 1:2.5 to 1:5, or even 1:3 to 1:4.

[0067] Polyether oligomers for use in this specification may have a number average molecular weight greater than 2000 g / mol, greater than 2500 g / mol, greater than 3000 g / mol, greater than 3500 g / mol, or even greater than 4000 g / mol.

[0068] Polyether oligomers for use herein may have number average molecular weights of up to 20,000 g / mol, up to 15,000 g / mol, up to 12,000 g / mol, up to 10,000 g / mol, up to 9,500 g / mol, up to 9,000 g / mol, up to 8,500 g / mol, or even up to 8,000 g / mol.

[0069] Polyether oligomers for use in this specification may have number average molecular weights in the range of 2,000 to 20,000 g / mol, 2,000 to 15,000 g / mol, 2,000 to 12,000 g / mol, 2,500 to 10,000 g / mol, 2,500 to 9,000 g / mol, 3,000 to 8,500 g / mol, 3,500 to 8,000 g / mol, or even 4,000 to 8,000 g / mol.

[0070] In one advantageous embodiment, the polyether oligomer for use in the present disclosure comprises at least two radical (co)polymerizable reactive groups.

[0071] In another advantageous embodiment, at least one radical (co)polymerizable reactive group of the polyether oligomer is selected from the group consisting of ethylenically unsaturated groups. In other words, the polyether oligomer for use herein may be an ethylenically unsaturated compound.

[0072] In a more advantageous embodiment of this disclosure, the ethylenically unsaturated group contained in the polyether oligomer is selected from the group consisting of (meth)acrylic groups, vinyl groups, styryl groups, and any combination or mixture thereof. More preferably, the ethylenically unsaturated group is selected from the group consisting of methacrylic groups, acrylic groups, and any combination or mixture thereof.

[0073] In a particularly preferred embodiment of this disclosure, the ethylenically unsaturated group contained in the polyether oligomer is a methacrylic group.

[0074] According to one advantageous embodiment of the curable precursor of this disclosure, the polyether oligomer for use herein is of the following formula: [ka] [In the formula, Y is a radical (co)polymerizable reactive group, particularly an ethylenically unsaturated group. Each R2 is independently selected from the group consisting of alkylene groups having 2 to 6 carbon atoms, n is an integer selected such that the number-average molecular weight of the polyether oligomer is at least 2000 g / mol. It holds.

[0075] In one particular embodiment, n is selected such that the number average molecular weight is at least 2000 g / mol, at least 3000 g / mol, or even at least 4000 g / mol. In another particular embodiment, n is selected such that the number average molecular weight is at most 20,000 g / mol, at most 15,000 g / mol, or even at most 10,000 g / mol. In yet another particular embodiment, n is selected such that the number average molecular weight is between 2000 and 20,000 g / mol, 3000 and 15,000 g / mol, or even 3000 and 10,000 g / mol, where all ranges include the endpoints.

[0076] The curable precursor of this disclosure may contain 1 to 50% by weight, 1 to 30% by weight, 1 to 20% by weight, 2 to 15% by weight, or 3 to 10% by weight of a polyether oligomer, the weight percentage being based on the total weight of the curable precursor.

[0077] Polyether oligomers are C1-C of (meth)acrylate component (a) 32 It is (co)polymerizable with (meth)acrylic acid ester monomer (i) and ethylenically unsaturated acidic compounds (ii).

[0078] The radical (co)polymerizable (meth)acrylate component (a) of the curable precursor disclosed herein is (iii) an ethylenically unsaturated monomer having a functional group, wherein the radical (co)polymerizable (meth)acrylate component (a) is C1-C 32(Meth)acrylic acid ester monomer (i) and ethylenically unsaturated acidic compound (ii) copolymerizable ethylenically unsaturated monomer It may also include the following.

[0079] While we do not wish to be constrained by theory, the presence of functionally grouped ethylenically unsaturated monomers in (meth)acrylate components is thought to have a beneficial effect on their shear strength and adhesive properties. Furthermore, functionally grouped ethylenically unsaturated monomers are thought to provide favorable surface interactions with thermally conductive particles, which contributes to providing a favorable rheological profile for the curable precursor of this disclosure.

[0080] The ethylenically unsaturated monomers having functional groups for use herein may have functional groups selected from the group consisting of amines, hydroxyls, amides, isocyanates, epoxides, nitriles, and any combination thereof.

[0081] The functionally active ethylenically unsaturated monomers may be selected from the group consisting of methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N-vinylpyrrolidone, N-vinylcaprolactam, (meth)acrylamide, N-vinylacetamide, 4-acryloylmorpholine, glycidyl (meth)acrylate, 2-isocyanatoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, acrylonitrile, and any mixture thereof.

[0082] The radical (co)polymerizable (meth)acrylate component (a) of the curable precursor disclosed herein may contain 1-15% by weight, 2-12% by weight, 3-10% by weight, 4-10% by weight, or even 5-10% by weight of an ethylenically unsaturated monomer having a functional group, the weight percentage being based on the total weight of the (meth)acrylate component.

[0083] The curable precursors disclosed herein may further comprise thermally conductive particles (e). The thermally conductive particles are used as fillers for the curable precursor to improve the thermal conductivity of the cured composition.

[0084] Thermally conductive particles for use in this specification may be selected from the group consisting of metal oxides, metal nitrides, metal hydroxides, metal particles, coated metal particles, ceramic particles, coated ceramic particles, and any combination or mixture thereof.

[0085] Preferably, the thermally conductive particles are 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 combination or mixture thereof.

[0086] More preferably, the thermally conductive particles are selected from the group consisting of aluminum oxide, aluminum hydroxide, boron nitride, and any combination or mixture thereof.

[0087] More preferably, the thermally conductive particles are selected from the group consisting of aluminum oxide, aluminum hydroxide, and any combination or mixture thereof.

[0088] The thermally conductive particles may include primary particles, aggregates of primary particles, or combinations thereof.

[0089] The thermally conductive primary particles and aggregates of primary particles may have isotropic, anisotropic, or a combination thereof.

[0090] The thermally conductive primary particles and aggregates of primary particles may be spherical, flat, or a combination thereof.

[0091] Exemplary thermally conductive primary particles and aggregates of primary particles for use herein are described, for example, in European Patent No. 3127973(A1) (Wieneke et al.).

[0092] The average particle diameter (d) of thermally conductive primary particles and aggregates of primary particles 50 The average particle diameter (d) of the thermally conductive primary particles and aggregates of primary particles may be 0.2 to 500 μm or 0.2 to 100 μm. 50 ) can be measured by laser diffraction.

[0093] Perpendicular thermal conductivity can be of paramount importance in several applications, such as thermal conductive filler applications. In these applications, isotropic thermal conductive particles (e.g., spherical particles) may be preferred because asymmetric fibers, flakes, or small plates may tend to align in the in-plane direction.

[0094] The thermally conductive particles may include thermally conductive particles that have undergone surface functionalization. The surface functionalization of the thermally conductive particles may have polarity selected from the group consisting of acidic functionality, basic functionality, hydrophobicity, hydrophilicity, and any combination or mixture thereof.

[0095] In one advantageous aspect of the present disclosure, surface functionalization of thermally conductive particles includes hydrophobic surface functionalization.

[0096] In the context of this disclosure, the term "hydrophobic surface functionalization" is intended to mean that the surface of the thermally conductive particles has little or no affinity for polar substances, particularly water, after suitable surface modification. The term "hydrophilic surface functionalization" is intended to mean that the surface of the thermally conductive particles has a relatively high affinity for polar substances, particularly water, after suitable surface modification.

[0097] The thermally conductive particles may further possess flame-retardant properties and / or electrical insulation properties.

[0098] The curable precursors disclosed herein may contain 20-95% by weight, 30-90% by weight, 30-80% by weight, 40-90% by weight, 40-80% by weight, 50-90% by weight, 50-80% by weight, 60-90% by weight, or 65-85% by weight of thermally conductive particles, the weight percentages being based on the total weight of the curable precursor.

[0099] The curable precursors disclosed herein may further contain a base (f).

[0100] As used herein, "base" means Arrhenius base. Furthermore, "base" refers to the hydroxide (OH) in the solution when dissolved in an aqueous solution. - This refers to a substance that increases the concentration of ions.

[0101] The base may be a tertiary amine or a combination of tertiary amines.

[0102] Tertiary amines are given by formula R 1 R 2 R 3 -N is present, in the formula, R 1 , R 2 and R 3 This group is independently an alkyl group or an aryl group. Suitable tertiary amine bases include, but are not limited to, p-toluidine ethoxylate (synonymous with N,N-bis(2-hydroxyethyl)-p-toluidine), N,N-dimethyl-p-toluidine, N,N-dimethylaniline, N,N-diethylaniline, and diisopropyl p-toluidine.

[0103] The base may also function as a polymerization accelerator for the curable precursor.

[0104] The curable precursor may contain, for example, 0.1 to 5% by weight or 0.1 to 3% by weight of base, based on the total weight of the curable precursor.

[0105] In some embodiments of the curable precursors disclosed herein, the curable precursors do not contain a base.

[0106] The curable precursors disclosed herein may have a pH value of less than 7. Preferably, the curable precursor may have a pH value of less than 6. The curable precursor may have a pH value of 3 to 6, or 4 to 5.

[0107] To measure the pH value of the curable precursor, the pH test paper or strip may be wetted with water, and the curable precursor may be applied to the pH test paper or strip.

[0108] To measure the pH value of a curable precursor, the components of the curable precursor may be dissolved in water, or the pH value may be measured using a pH meter. When measuring the pH of a curable precursor using a pH meter, each water-soluble component of the curable precursor, expressed as a percentage in grams, may be dissolved in an amount of water equivalent to the difference between the sum of these percentages and 100% in grams, and the pH value of the resulting aqueous solution is measured. Components of the curable precursor that are insoluble in water do not dissolve in water and cannot contribute to the measurement, so they are not added during the measurement. "Insoluble in water" should be understood as having a solubility in water of 0.2 g / L or less at 23°C, and "water-soluble components" should be understood as components with a solubility in water greater than 0.2 g / L at 23°C. In addition, particulate packing materials such as thermally conductive particles are not added when measuring pH values ​​using a pH meter.

[0109] In some embodiments, the pH value of the curable precursor is less than 7, even when a base (f) is added. For example, if the curable precursor contains a base in an amount of 0.1 to 5% by weight based on the total weight of the curable precursor, the curable precursor may have a pH value of less than 7.

[0110] Surprisingly, nitroxides act as inhibitors, effectively preventing core polymerization not only when acidic compounds are present in the curable precursor, but also when the curable precursor is acidic, i.e., when the pH of the curable precursor is less than 7.

[0111] The curing precursor may further contain additives such as dispersants, antioxidants, flame retardants, or dyes.

[0112] In some embodiments, the curable precursors disclosed herein do not contain urethane (meth)acrylate.

[0113] According to one advantageous aspect of the present disclosure, the curable precursor is (substantially) free from plasticizers, thixotropes, silicon compounds, halogen compounds, isocyanate compounds, and any combination or mixture thereof.

[0114] According to another advantageous aspect of this disclosure, the curable precursor is (substantially) solvent-free, particularly organic solvents.

[0115] According to yet another typical embodiment of the present disclosure, the curable precursor further comprises an initiator for radical polymerization.

[0116] The term "initiator" is intended to refer to a substance or group of substances that can start, initiate, or contribute to the curing process of a curable precursor, that is, a substance that can start, initiate, or contribute to the radical (co)polymerization of (meth)acrylate components.

[0117] The initiators used herein may contain or generate free radicals. Examples of initiators used herein include, but are not limited to, organic peroxides. Examples of organic peroxides include hydroperoxides, ketone peroxides, and diacyl peroxides. Examples of hydroperoxides include cumene hydroperoxide, tert-pentyl hydroperoxide, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide. An example of a ketone peroxide is methyl ethyl ketone peroxide. An example of a diacyl peroxide is dibenzoyl peroxide. Other examples of organic peroxides include tert-butylperoxybenzoate, dicumyl peroxide, 1,3-di-(2-tert-butylperoxyisopropyl)benzene, tert-butylcumyl peroxide, and di-tert-butyl peroxide.

[0118] Preferably, dibenzoyl peroxide is used as an initiator.

[0119] The curable precursor may contain, for example, 0.1 to 2% by weight or 0.1 to 1% by weight of an initiator, based on the total weight of the curable precursor.

[0120] In one typical embodiment, the curable precursor of the present disclosure is in the form of a two-component composition having a first part and a second part, the first part and the second part remaining separate before being combined to form a curable composition.

[0121] The first part is C1~C 32The first part comprises a radical (co)polymerizable (meth)acrylate component containing a (meth)acrylic acid ester monomer and an ethylenically unsaturated acidic compound, a crosslinking agent, and a nitroxide. The second part comprises an initiator for radical polymerization. With respect to the first part, core polymerization of the curable precursor is effectively prevented by a nitroxide inhibitor, and the first part can be stored for several weeks or months, for example, in a drum of 100-200 liters. Curing can be initiated by combining the first and second parts, and rapid curing is possible even at room temperature despite the stabilization of the first part.

[0122] In an advantageous embodiment of this disclosure, the two portions of the curable precursor may be mixed in a first-to-second-part ratio ranging from 10:1 to 1:1, or from 5:1 to 3:1. Preferably, the two portions of the curable precursor may be mixed in a first-to-second-part ratio of 4:1.

[0123] A method for producing a cured composition from a curable precursor disclosed herein, wherein the method is The objective is to provide a curable precursor, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (i) C1~C 32 (meth)acrylic acid ester monomer and (ii) Ethylene unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for (meth)acrylate components comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, Includes, C1~C 32 The objective is to provide a curable precursor in which the (meth)acrylic acid ester monomer (a)(i) does not contain any functional groups other than the (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acidic functional groups derived from phosphoric acid. To provide an initiator for the radical polymerization of a curable precursor, Mixing the curing precursor and the initiator, The process involves curing a mixture of a curable precursor and an initiator, Methods including the above are further disclosed herein.

[0124] In particular, all specific and preferred embodiments relating to (meth)acrylate components, crosslinking agents, nitroxides, and initiators described above in the context of curable precursors are fully applicable to the methods described above.

[0125] The first and second portions of the curable precursor can be extruded from a 2K cartridge or 2K system using a static or dynamic mixer.

[0126] As used herein, “hardening” or “curing” a composition or mixture is used interchangeably and refers to a (co)polymerization and / or crosslinking reaction involving one or more materials contained in the composition, including a chemical (co)polymerization technique (e.g., a chemical reaction that forms radicals effective for (co)polymerizing radical (co)polymerizable compounds such as ethylenically unsaturated compounds).

[0127] The curable precursors disclosed herein can be cured without the use of any chemical rays, particularly UV light.

[0128] The curable precursors disclosed herein can be cured without the use of any additional thermal energy.

[0129] The curable precursors disclosed herein can be cured without requiring expensive catalysts such as platinum.

[0130] Despite the stabilization of reactive compounds in the curable precursors, such as (meth)acrylate components and crosslinking agents, by nitroxide inhibitors, curing can be performed very rapidly at room temperature without the need for UV light or high temperatures. A bonding strength (overlap shear strength) of at least 1 MPa can be achieved after only 30 minutes of curing time.

[0131] The cured composition produced by the method disclosed herein may be in the form of an adhesive gap filler.

[0132] In the context of this disclosure, the expression “adhesive gap filler” is intended to refer to an adhesive composition used to at least partially fill a spatial gap between a first surface and a second surface. After mixing the first and second portions of a curable precursor, the curable precursor can flow into and fill the spatial gap between the first and second surfaces, and after curing of the curable precursor, the cured composition provides an adhesive bond between the first and second surfaces having good mechanical properties and good adhesive strength. The first surface may be a battery cell of an electric vehicle, and the second surface may be a cooling plate. The adhesive gap filler may become a thermally conductive adhesive gap filler by adding thermally conductive particles.

[0133] Curing may be carried out at a temperature below 50°C, or at a maximum temperature of 40°C or 30°C, or at room temperature (23°C). Preferably, curing is carried out at room temperature (23°C).

[0134] Typically, curing takes up to 1 hour. Curing may also take up to 45 minutes or up to 30 minutes. Typically, a cured composition with an adhesive strength of at least 0.7 MPa is obtained after 30 minutes of curing at room temperature (23°C). The adhesive strength of the cured composition after 30 minutes of curing at room temperature (23°C) may be at least 1 MPa, or at least 2 MPa, or at least 3 MPa, depending on the amount of initiator used.

[0135] In one advantageous embodiment, the curable precursor of the present disclosure can be cured at 23°C to a curing percentage of more than 90%, more than 95%, more than 98%, or even more than 99% after a curing time of 72 hours or less, 48 ​​hours or less, or even 24 hours or less, depending on the amount of initiator used.

[0136] The curing time can be adjusted as desired, depending on the target application and manufacturing requirements.

[0137] Cured compositions produced by the methods disclosed herein may have a thermal conductivity of at least 0.1 W / mK, at least 0.3 W / mK, at least 0.5 W / mK, at least 0.7 W / mK, at least 1.0 W / mK, at least 1.2 W / mK, or at least 1.5 W / mK, as measured according to the test methods described in the Experimental Section.

[0138] Cured compositions produced by the methods disclosed herein may have overlapping shear strengths (OLS) of at least 0.5 MPa, at least 2.0 MPa, at least 2.5 MPa, at least 3.0 MPa, at least 3.5 MPa, at least 4.0 MPa, or at least 4.5 MPa, as measured according to the test methods described in the Experimental Section.

[0139] Cured compositions produced by the methods disclosed herein may have overlapping shear strengths (OLS) in the ranges of 0.5 to 30.0 MPa, 2.0 to 8.0 MPa, 2.5 to 8.0 MPa, 2.5 to 7.0 MPa, 3.0 to 7.0 MPa, 3.5 to 6.5 MPa, or 4.0 to 6.0 MPa, as measured according to the test methods described in the Experimental Section.

[0140] The cured composition may have an elongation at break of at least 5%, at least 8%, or at least 10%, as measured according to the test methods described in the experimental section.

[0141] The curable precursors and cured compositions produced from these curable precursors disclosed herein may be used for adhesive applications and / or thermal management applications in the automotive industry.

[0142] The above-described curable precursors and curing compositions may be used, in particular, for the manufacture of battery modules containing multiple battery cells, for use in the automotive industry.

[0143] With regard to embodiments of curable precursors containing thermally conductive particles, the curable precursor and cured composition may be used as thermally conductive adhesives for battery applications. [Examples]

[0144] Test method Preparation of test formulations: Samples for testing mechanical and thermal behavior are prepared from a 4:1 (volume ratio) mixture of two components (component A:component B) extruded from a 2K cartridge using a static mixer (standard 3M Gold Quadro nozzle for 50 mL cartridges or SULZER MF 10-18 nozzle for 200 mL cartridges). The preparation of both components is described below. During the open time, the resulting paste is applied as a film to the surface of the test panel. The surface of the test sample (25 mm × 100 mm × 4 mm) (aluminum, grade EN AW2024T3) for the overlap shear strength test is sandblasted with pure corundum having a particle size of approximately 135 micrometers before bonding. The test sample is left at ambient room temperature (23°C ± 2°C, relative humidity 50% ± 5%) for 7 days. Various performance tests are measured as described below.

[0145] 1. Thermal conductivity test The thermal conductivity of the cured composition is measured at 23°C in accordance with ASTM E1461 using laser flash analysis (LFA) with a Light Flash Apparatus LFA 467 HyperFlash®, commercially available from Netzsch GmbH, Germany, for a sample with a thickness of 2 mm.

[0146] 2. Overlap shear strength (OLS) according to DIN EN 1465 The overlapping shear strength is determined according to DIN EN 1465 using a Zwick Z050 tensile testing machine (commercially available from Zwick GmbH & Co. KG, Ulm, Germany) operating at a crosshead speed of 10 mm / min. For the preparation of the overlapping shear strength test assembly, a paste obtained from a mixture of components A and B is spackled onto one surface of the test panel. The aluminum EN AW2024T3 test panel is sandblasted before joining. The sample is then covered with a second aluminum strip to form a 13 mm overlapping joint. This ensures the formation of a joint line with a thickness of approximately 300 micrometers using glass beads with a selected diameter distribution. The overlapping joint is then clamped together using two binder clips, and the test assembly is stored at room temperature for a further 7 days after joining, and then placed in an air-circulating oven at 80°C for 30 minutes. The sample is tested directly at room temperature or subjected to aging before testing. For each example, five samples are measured, the results are averaged, and reported in MPa.

[0147] 3. Elongation at fracture according to DIN EN ISO 527-2-5A Elongation at break is measured using a Zwick Z050 tensile testing machine (commercially available from Zwick GmbH & Co. KG, Ulm, Germany) operating at a crosshead speed of 10 mm / min, in accordance with DIN ISO 527-2-5A. A film with a thickness of approximately 2 mm is prepared according to the above procedure. Five dogbone-shaped samples are punched out according to the geometry of DIN ISO 527-2-5A (dimensions 25 mm × 4 mm × 2 mm) and used for further mechanical testing. Measurements are taken for each sample, and the results are averaged and reported as a percentage for elongation at break.

[0148] 4. Shore A hardness according to DIN EN ISO 868 Shore A hardness testing is performed using the ZwickRoell 3115 (commercially available from Zwick GmbH&Co.KG, Ulm, Germany) in accordance with DIN EN ISO 868. A film with a thickness of approximately 1 mm is prepared according to the above procedure. Three samples are used for the Shore A hardness test. Measurements are taken for each sample, and the results are averaged and reported.

[0149] 5.Viscosity measurement The viscosity of the test sample is measured at 20°C using an Anton Paar rheometer MCR 302 with Anton Paar's RheoCompass software. The measurement is performed over a period of 0.1 to 5 seconds. -1 The sweep was performed using frequency sweep at a shear rate of 0.1s. -1 So, we take one measurement point every 2 seconds, for a total of 90 points, and then 0.5 seconds -1 So, we take 20 measurement points, one every 2 seconds, and then 1.0s -1 So, we take one measurement point every 1 second, for a total of 20 points, for 5 seconds. -1 We then took 40 measurement points, one at a time every 0.5 seconds.

[0150] raw materials In the embodiment, the following raw materials are used.

[0151] 2-Ethylhexylacrylate (2-EHA) is an acrylic acid ester monomer obtained from BASF AG, Germany.

[0152] Acrylic acid (AA) is a monomer obtained from BASF AG, Germany.

[0153] Diol-6000-DMA is a dimethacrylate polyether oligomer with a number-average molecular weight of approximately 6000 g / mol, obtained from 3M Espe GmbH, Germany.

[0154] GLP is a dimethacrylate crosslinking agent derived from phosphoric acid and is obtained from 3M Espe GmbH, Germany.

[0155] Cyclohexyl methacrylate (CHMA) is a methacrylate ester monomer obtained from BASF AG, Germany.

[0156] 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4-OH-TEMPO, TEMPOL) is a nitroxide obtained from Evonik Industries AG, Germany.

[0157] Martoxid™ 2320 is an aluminum oxide-based thermally conductive filler obtained from Martinswerk, Germany.

[0158] BF083 is an aluminum hydroxide-based thermally conductive and flame-retardant filler, obtained from Nippon Light Metal Co., Ltd. (Japan).

[0159] B53 is an aluminum hydroxide-based flame retardant and thermally conductive filler, obtained from Nippon Light Metal Co., Ltd. (Japan).

[0160] SpaceRite S-11 is an aluminum hydroxide-based flame retardant and thermally conductive filler, obtained from JMHuber Corporation, New Jersey, USA.

[0161] Martinal TM 2550 is an aluminum hydroxide-based thermally conductive and flame-retardant filler obtained from Martinswerk, Germany.

[0162] Martinal TM 2590 is an aluminum hydroxide-based thermally conductive and flame-retardant filler obtained from Martinswerk, Germany.

[0163] Martinal ON908 is an aluminum hydroxide-based thermally conductive and flame-retardant filler obtained from Martinswerk, Germany.

[0164] Apyral 200SM is an aluminum hydroxide-based thermally conductive and flame-retardant filler obtained from Nabaltec, Germany.

[0165] Pergaquick A150 PM is a p-toluidine ethoxylate base obtained from Pergan GmbH, Germany.

[0166] BYK-W 9010 is a dispersant obtained from BYK-Chemie GmbH, Germany.

[0167] DISPERBYK-145 is a dispersant obtained from BYK-Chemie GmbH, Germany.

[0168] Irganox 1076 is an antioxidant obtained from BASF, Germany.

[0169] Irgafos 168 is an antioxidant obtained from BASF, Germany.

[0170] 4-methoxyphenol (MEHQ) is an inhibitor obtained from Sigma-Aldrich, Germany.

[0171] Alpha-methyl styryl polyurea resin (AMSPU) is an α-methylstyrene-functional polyether oligomer having a urea bond and is used to dilute the initiator in the second part of the curable precursor. The α-methylstyrene-functional oligomer having a urea bond was prepared as follows: 120 g (0.6 mol) of 3-isopropenyl-α,α-dimethylbenzyl isocyanate (commercially available as TMI from Cytec Industries, West Peterson, NJ, USA) and 600 g (0.6 amine equivalents) of amine-terminated polyethylene (D2000, commercially available as Jeffamine® D2000 from Huntsman Chemical Co., Houston, TX, USA, a bifunctional amine-terminated polyethylene with a nominal reported MW of 2000) were combined in a glass container with stirring at room temperature and left overnight at room temperature. Infrared spectroscopy (IR) indicated a complete reaction by the disappearance of the isocyanate band at 2265 cm⁻¹. The calculated molecular weight of the α-methylstyrene-functional oligomer is 2460 g / mol.

[0172] Irgazin Red L 3670 HD is a red pigment obtained from BASF AG, Germany.

[0173] Peroxan BP-Paste 50 PF-1 is a dibenzoyl peroxide, which is a polymerization initiator, and is obtained from Pergan GmbH, Germany.

[0174] Examples 1-5 (EX1-EX5) and Comparative Examples 1 and 2 (CEX1 and CEX2) For Examples 1-5 and Comparative Example 1, curable precursors having the formulations shown in Table 1 were prepared. The formulations in Table 1 represent the first part (Part A) of the two-component formulation of the curable precursor.

[0175] The curable precursors were prepared by combining the raw materials from the list of materials in Table 1 in a speed mixer (DAC 600.2 VAC-P, available from Hauschild Engineering, Germany) by stirring at 2000 rpm for 90 seconds until a homogeneous mixture was obtained. The materials were then slightly degassed to remove trapped air. Acrylic acid ester monomers, ethylenically unsaturated acidic compounds, crosslinking agents, and nitroxides were added first, followed by polyether oligomers, various thermally conductive particles, and other additives in a continuous process. Comparative Example 1 did not contain any nitroxides. 100 g of each curable precursor composition listed in Table 1 was prepared (Component A). [Table 1]

[0176] Because glass containers have limited oxygen diffusion, the stability of the curable precursor (Agent A) for core polymerization was tested using glass containers. Before filling the glass containers, the curable precursor material was degassed in a Speedmixer under vacuum (approximately 900 mbar) for 1:30 minutes. The material was completely filled into the glass containers (52.5 g of material in a 25 ml glass container), taking care to ensure there were no air bubbles in the material to guarantee a low-oxygen atmosphere. This experimental setup simulates the conditions in the center of a drum with a volume of 100-200 liters that is completely filled with material. For each formulation, three glass containers were filled.

[0177] The filled glass containers were stored at different temperatures (50°C, 65°C, and 80°C) to accelerate the aging of the test samples. [Table 2]

[0178] As can be seen from Table 2, the comparative example (CEX1) without the addition of 4-OH-TEMPO had already completely cured after 3 days at 65°C. A small amount of 4-OH-TEMPO (Example 1) prevents core polymerization, but shows an increase in viscosity after 3 days of storage at 65°C. The use of 0.002% by weight or more of 4-OH-TEMPO stabilizes the formulation for at least 5 days at 65°C (Examples 2-5).

[0179] For Examples 1-5, the pH of the curable precursor was measured by dissolving the water-soluble component of the curable precursor (i.e., the component with a water solubility greater than 0.2 g / L at 23°C) in water and measuring the pH of the aqueous solution. For the measurement, 0.5 g of acrylic acid, 0.65 g of GLP, and 0.42 g of Pergaquick A150 PM were dissolved in 98.43 g of water, and the pH of the aqueous solution was measured using a pH meter. The pH value was less than 3.

[0180] Example 6 (EX6) and Comparative Example 2 (CEX2) For Example 6 and Comparative Example 2, the first portion of the two-component mixture of the curable precursor having the formulation shown in Table 1 was prepared as described above for Examples 1 to 5. Samples for testing core polymerization stability were prepared as described above for Examples 1 to 5.

[0181] For Example 6 and Comparative Example 2, the first (Part A) and second (Part B) components of the two-component composition of the curable precursor were prepared separately by combining the raw materials from the list of materials in Table 1 (Part A) and Table 3 (Part B) in a speed mixer (DAC 600.2 VAC-P, available from Hauschild Engineering, Germany) by stirring at 2000 rpm for 90 seconds until a homogeneous mixture was obtained. The materials were then slightly degassed to remove trapped air. For Part A, the acrylic acid ester monomer, ethylenically unsaturated acidic compound, crosslinking agent, and nitroxide were added first, followed by the addition of polyether oligomer, various thermally conductive particles, and other additives in a continuous process. The initiator for radical polymerization is present only in Part B. For Part B, the alpha-methylstyryl polyurea resin was added first, followed by the addition of various thermally conductive particles, and finally the addition of a peroxide initiator. During mixing, the mixing temperature should not exceed 40°C. For each of the curing precursor compositions listed in Table 1 (Agent A) and Table 3 (Agent B), a 100g first portion and a 100g second portion were prepared.

[0182] Subsequently, the two components were filled into a 2K cartridge in a volume ratio of A:B = 4:1, and the mixture was applied to the surface of the test panel described above. In Tables 1 and 3, all concentrations are shown in weight percent. Comparative example CE2 contains no nitroxide.

[0183] The overlapping shear specimens, the dogbone-shaped specimens for fracture elongation, and the specimens for thermal conductivity and hardness measurements are cured at room temperature for 7 days. The measurements are carried out as described above in the Test Methods section.

[0184] The test results are shown in Table 4. [Table 3] [Table 4]

[0185] As can be seen from Table 4, Example 6 (with 0.003 wt% 4-OH-TEMPO added) exhibits similar performance to Comparative Example 2 (without 4-OH-TEMPO added), but shows significantly increased stability with respect to core polymerization. In Comparative Example 2, core polymerization was observed in less than 24 hours at 50°C and less than 9 hours at 80°C (in both cases the composition polymerized completely), whereas in Example 6, core polymerization was not observed after 21 days at 50°C and 3 days at 80°C.

[0186] For Example 6, the curing rate was determined by measuring the vibrational rheology. The gelation point (i.e., the point where the storage modulus and loss modulus are equal) occurred approximately 9 minutes after the two parts of the two-component mixture were combined. This indicates that even with 0.003 wt% 4-OH-TEMPO, the curing time at room temperature is fast.

[0187] Examples 7 and 8 (EX7 and EX8) and Comparative Example 3 (CEX3) For Examples 7 and 8 and Comparative Example 3, the first (Part A) and second (Part B) components of the two-component curable precursor are prepared separately by combining the raw materials from the list of materials in Table 5 (Part A) and Table 6 (Part B) in a planetary mixer and mixing until a homogeneous mixture is obtained. The materials are then slightly degassed to remove trapped air. For Part A, acrylic acid ester monomers, polyether oligomers, and nitroxides are added first, followed by the addition of various thermally conductive particles and other additives in a continuous process. Finally, ethylenically unsaturated acidic compounds and crosslinking agents are added, followed by the addition of a base after mixing. The initiator for radical polymerization is present only in Part B. For Part B, alpha-methylstyryl polyurea resin is added first, followed by the addition of various thermally conductive particles, and finally the addition of a peroxide initiator. During mixing, the mixing temperature should not exceed 40°C. For each of the curing precursor compositions listed in Table 5 (Agent A) and Table 6 (Agent B), a first portion of 500 L (1050 kg) and a second portion of 300 L (630 kg) were prepared.

[0188] For Example 8 and Comparative Example 3, samples for testing core polymerization stability at 50°C and 80°C were prepared from the first portion (Agent A) of the curable precursor described above for Examples 1 to 5.

[0189] The test results are shown in Table 7. [Table 5] [Table 6] [Table 7]

[0190] As can be seen from Table 7, Example 8 (with 0.003 wt% 4-OH-TEMPO added) exhibits similar performance to Comparative Example 3 (without 4-OH-TEMPO added), but shows significantly increased stability with respect to core polymerization. In Comparative Example 3, core polymerization was observed in less than 24 hours at 50°C and less than 9 hours at 80°C (in both cases the composition polymerized completely), whereas in Example 8, core polymerization was not observed after 21 days at 50°C and 3 days at 80°C.

[0191] In Comparative Example 3, core polymerization was observed in a drum filled with 150 L of the composition in less than two weeks at room temperature (23°C) (core polymerization in the center of the drum), whereas in Example 8, core polymerization was not observed after storing a drum filled with 150 L of the composition at room temperature for six months. The following are exemplary embodiments. [Item 1] A curable precursor for an adhesive composition, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (I C 1 ~C 32 (meth)acrylic acid ester monomer and (ii) Ethylene unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for the (meth)acrylate component comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, Includes, Said C 1 ~C 32 A curable precursor wherein the (meth)acrylic acid ester monomer (a)(i) does not contain any functional groups other than the (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acidic functional groups derived from phosphoric acid. [Item 2] Said C 1 ~C 32 The curable precursor according to item 1, wherein the (meth)acrylic acid ester monomer is selected from the group consisting of isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, methyl (meth)acrylate, benzyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and any mixture thereof. [Item 3] The curable precursor according to item 1 or 2, wherein the ethylenically unsaturated acidic compound comprises monomers, oligomers, and polymers having ethylenically unsaturated and acidic and / or acid precursor functionalities. [Item 4] The curable precursor according to any one of items 1 to 3, wherein the nitroxide is selected from the group consisting of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), its derivatives, and combinations thereof. [Item 5] The curable precursor according to any one of items 1 to 4, wherein the nitroxide is 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL). [Item 6] (d) A polyether oligomer having a number average molecular weight of at least 2000 g / mol and containing at least one radical (co)polymerizable reactive group, wherein the number average molecular weight is determined by gel permeation chromatography (GPC). A curable precursor as described in any one of items 1 to 5, further including the above. [Item 7] The radical (co)polymerizable (meth)acrylate component (a) is (iii) an ethylenically unsaturated monomer having a functional group, wherein the C of the radical (co)polymerizable (meth)acrylate component (a) 1 ~C 32 (Meth)acrylic acid ester monomer (i) and ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated acidic compound (ii), A curable precursor as described in any one of items 1 to 6, further including the above. [Item 8] (e) Thermally conductive particles A curable precursor as described in any one of items 1 to 7, further including the above. [Item 9] (f) base A curable precursor as described in any one of items 1 to 8, further including the above. [Item 10] The curable precursor according to item 9, wherein the base is a tertiary amine or a combination of tertiary amines. [Item 11] The curable precursor described above is a curable precursor according to any one of items 1 to 10, wherein the curable precursor does not contain a base. [Item 12] The curable precursor according to any one of items 1 to 11, wherein the curable precursor further comprises an initiator for radical polymerization. [Item 13] A method for producing a cured composition from a curable precursor described in any one of items 1 to 12, wherein the method is The objective is to provide a curable precursor, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (I C 1 ~C32 (meth)acrylic acid ester monomer and (ii) Ethylene unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for the (meth)acrylate component comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, Includes, Said C 1 ~C 32 The objective is to provide a curable precursor in which the (meth)acrylic acid ester monomer (a)(i) does not contain any functional groups other than the (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acidic functional groups derived from phosphoric acid. To provide an initiator for the radical polymerization of the curable precursor, Mixing the curable precursor and the initiator, The mixture of the curable precursor and the initiator is cured, Methods that include... [Item 14] The method according to item 13, wherein curing is carried out at a temperature below 50°C, preferably at room temperature (23°C). [Item 15] Use of any one of items 1 to 12 for adhesive applications and / or thermal management applications in the automotive industry.

Claims

1. A curable precursor for an adhesive composition, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (i) C １ ~C ３２ (Meth)acrylic acid ester monomer and (ii) Ethylene-unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for the (meth)acrylate component comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, It contains but does not contain bases. Said C １ ~C ３２ A curable precursor wherein the (meth)acrylic acid ester monomer (a)(i) does not contain any functional groups other than the (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acidic functional groups derived from phosphoric acid.

2. Said C １ ~C ３２ The curable precursor according to claim 1, wherein the (meth)acrylic acid ester monomer is selected from the group consisting of isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, methyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and any mixture thereof.

3. The curable precursor according to claim 1, wherein the ethylenically unsaturated acidic compound comprises monomers, oligomers, and polymers having ethylenically unsaturated and acidic and / or acid precursor functionalities.

4. The curable precursor according to claim 1, wherein the nitroxide is selected from the group consisting of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), its derivatives, and combinations thereof.

5. The curable precursor according to claim 1, wherein the nitroxide is 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL).

6. (d) A polyether oligomer having a number average molecular weight of at least 2000 g / mol and containing at least one radical (co)polymerizable reactive group, wherein the number average molecular weight is determined by gel permeation chromatography (GPC). The curable precursor according to claim 1, further comprising:

7. The radical (co)polymerizable (meth)acrylate component (a) is (iii) An ethylenically unsaturated monomer having a functional group, wherein the radical (co)polymerizable (meth)acrylate component (a) is C １ ~C ３２ (meth)acrylic acid ester monomer (i) and ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated acidic compound (ii), The curable precursor according to claim 1, further comprising:

8. (e) Thermally conductive particles The curable precursor according to claim 1, further comprising:

9. (f) base The curable precursor according to claim 1, further comprising:

10. The curable precursor according to claim 9, wherein the base is a tertiary amine or a combination of tertiary amines.

11. A method for producing a cured composition from a curable precursor according to any one of claims 1 to 10, wherein the method is The objective is to provide a curable precursor, wherein the curable precursor is (a) A radical (co)polymerizable (meth)acrylate component, (i) C １ to C ３２ (meth)acrylic acid ester monomer, (ii) Ethylene-unsaturated acidic compounds, A radical (co)polymerizable (meth)acrylate component, (b) A crosslinking agent for the (meth)acrylate component comprising at least one acidic functional group derived from phosphoric acid and at least one radical (co)polymerizable reactive group, (c) Nitroxide and, Includes, Said C １ ~C ３２ The present invention provides a curable precursor wherein the (meth)acrylic acid ester monomer (a)(i) does not contain any functional groups other than the (meth)acrylic acid ester group, and the ethylenically unsaturated acidic compound (a)(ii) does not contain any acidic functional groups derived from phosphoric acid. To provide an initiator for the radical polymerization of the curable precursor, Mixing the curable precursor and the initiator, The mixture of the curable precursor and the initiator is cured, Methods that include...

12. The method according to claim 11, wherein the curing is performed at a temperature of less than 50°C.

13. Use of the curable precursor according to claim 1 for adhesive applications and / or thermal management applications in the automotive industry.

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