High heat-resistant contact fillers and their use

Abstract

The present invention relates to a high heat-resistant contact filler comprising component A and component B. Component A comprises a polyacrylate-based silane-functional prepolymer or a mixture of silane-functional prepolymers having at least one polyacrylate-based silane-functional prepolymer, a plasticizer which is a multi-functional carboxylic acid ester, a wetting dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN 19645, a mixture of functional organosilanes, ZnO, and yet another thermally conductive filler or a mixture of multiple thermally conductive fillers. Furthermore, component B comprises a plasticizer which is a multi-functional carboxylic acid ester, a wetting dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN 19645, a thermally conductive filler or a mixture of multiple thermally conductive fillers, water, an organometallic catalyst, an antioxidant or a mixture of multiple antioxidants. The volume mixing ratio of component A to component B is from 1:1 to 10:1.

Description

[Technical Field]

[0001] The operation of electronic and energy systems generates heat, and this heat needs to be dissipated quickly and effectively from the heat-generating units. One example is electric mobility, which operates at extremely high temperatures, particularly due to the use of solid-state battery cells. [Background technology]

[0002] Solid or solid-state battery cells represent a novel development in battery technology, possessing a solid electrolyte instead of a liquid electrolyte, compared to the lithium-ion and lithium polymer aggregates available today. The greatest advantage of this novel technological development is the higher potential charge density that can be achieved with such batteries. This high charge density is partially compensated for by the currently relatively low power density, which results from the low charge density of common solid electrolytes such as glass-ceramic electrolytes. Yet another technically significant advantage of solid batteries is their extremely high flame retardancy and consistent behavior even at extreme ambient temperatures, which makes it possible to simplify the extremely complex temperature management of batteries, especially cooling, which appears to be possible simply by combining passive heat dissipation with switchable heating means. The ability to operate batteries without the risk of short circuits, cell damage, and battery fires that are difficult to extinguish at higher temperatures creates a high demand for heat resistance in the heat conductive solution used.

[0003] In this field, thermally conductive contact fillers are often used for both heat supply and heat dissipation, as they serve two main purposes.

[0004] The thermally conductive contact filler conducts heat and simultaneously bonds active components together.

[0005] From the literature, silane-functionalized prepolymer-based contact fillers for use in thermal management are known (International Publication No. 2020 / 165288, U.S. Patent Application Publication No. 2015 / 166859, German Patent Application Publication No. 102018102989). However, as the operating temperatures in electric vehicles are increasing, conventional silane-functionalized prepolymer-based contact fillers have been found to be unsuitable for this application due to thermal instability, as they degrade over time and cannot be guaranteed to provide the desired functionality over the entire operating life of such electric vehicles.

[0006] Therefore, for applications with extremely high operating temperatures, silicon-based contact fillers are used. Although silicon-containing solutions have outstanding heat resistance, they cannot be used universally because they have a negative effect on electronic circuits and connectors. Silicon-containing base oils are generally known to have small amounts of volatile silicon compounds that can be released from the base oil into the ambient air. These volatile silicon compounds can accumulate on the surface around active components. If painting or bonding processes are subsequently performed on such contaminated surfaces, the adhesion of the paint or adhesive layer may be lost. If volatile silicon compounds reach electrical contacts, the electrical contacts may be damaged by the formation of sparks, leading to the formation of an insulating oxide layer, thereby impairing or destroying the function of the contacts. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2020 / 165288 [Patent Document 2] U.S. Patent Application Publication No. 2015 / 166859 [Patent Document 3] German Patent Application Publication No. 102018102989 [Overview of the project] [Problems that the invention aims to solve]

[0008] Because there is a growing demand for high heat-resistant contact fillers that do not have the aforementioned drawbacks, the present invention aims to provide a high heat-resistant contact filler that has desired properties that allow it to be used at extremely high operating temperatures, while simultaneously being able to withstand high heat transfer and having a viscosity suitable for such applications. [Means for solving the problem]

[0009] This problem of the present invention has been remarkably resolved by the high heat-resistant contact filler having the features of claim 1. Advantageous developments of the concept of the present invention are subject to the prior claims. Further advantageous developments of the contact filler according to the present invention are found in the description and examples.

[0010] In the spirit of this invention, the defining term "prepolymer" is understood to mean any polymer or oligomer that has been pre-stretched by a special preliminary reaction and / or has had novel functional groups introduced by a special preliminary reaction that enable a selected polymerization reaction to be carried out in any further step.

[0011] In the spirit of this invention, the defining term "silane-functionalized prepolymer" is understood to refer to an oligomer, polymer, or prepolymer with alkoxysilane functionality. Silane-modified prepolymers condense by the elimination of alkoxy groups in the presence of water, forming a coarse network structure. Based on the definition of prepolymers described above, it is not important here whether the prepolymer backbone already consists of a prepolymer (e.g., a polyurethane-based prepolymer) or is a pure oligomer or polymer. All silane-modified polymers are simultaneously prepolymers according to the definition above, due to a special preliminary reaction of silane functionalization.

[0012] Since there is no general consensus on the nomenclature and distinction of various silane-modified prepolymers, all types of silylated polymers and prepolymers that can be produced industrially or non-industrially are considered silane-functionalized prepolymers in the spirit of this invention.

[0013] In the spirit of this invention, the defining term "plasticizer" is understood to mean a low-viscosity additive that is non-reactive in selected crosslinking chemistry and used, on the one hand, to reduce the viscosity of a liquid component. After the matrix hardens, the plasticizer remains within the polymer network and reduces the mechanical properties of the polymer formed within the network, resulting in a polymer that is generally more flexible than a very coarsely crosslinked polymer network, thus making the polymer softer, more elastic, more flexible, and / or more stretchable. Chemically, the plasticizer is not covalently bonded to the polymer matrix, but the polar groups of the plasticizer interact with the polar groups of the polymer network, accumulating between the polymer chains, thereby increasing the flexibility of the polymer chains and making the overall structure more flexible. Plasticizers are generally low molecular weight, but it is also possible to use polymer plasticizers, for example, polypropylene glycol-based plasticizers. Typical examples of plasticizers include chemical structure-based substances such as carboxylic acid esters, fatty oils, soft resins, and camphor.

[0014] In the spirit of this invention, the defining term "wetting dispersion additive" is understood to refer to an additive that possesses the property of mixing two immiscible substances with each other. This is generally known from fluid-fluid systems that form emulsions. However, it is also important when forming stable liquid-solid systems. Stabilization of the dispersion is achieved by compatibilizing interfacial tension and better wetting of solid particles with the liquid medium. The additive is used to wet the solid as much as possible, ideally completely, with the liquid phase, but also promotes the shear effect necessary to fractionate aggregates into individual particles during manufacturing. In addition, the wetting dispersion additive remains on the particle surface and stabilizes the particles in the liquid phase, resulting in a stable dispersion or at least avoiding re-aggregation and, as much as possible, rapid sedimentation / deposition of the filler. Wetting dispersion additives, used as surfactants, allow a portion of their amphiphilic molecules or polymers to dissolve well in the liquid phase. The excellent steric effect of the chains around the particle surface is the main reason for particle stabilization. This steric effect causes repulsion when particles come extremely close together, requiring them to maintain a constant distance from each other, thereby minimizing mechanical interactions (e.g., aggregation, particle abrasion leading to high viscosity). This effect can be achieved through steric repulsion, electrostatic repulsion (using a similar principle), or by introducing charges via chemical functional groups (carboxylates, aluminum groups, etc.). Combining both modes of action can also achieve electrosteric stabilization of particles. Generally, electrostatic and electrosteric repulsion work very well with relatively polar liquids, while steric repulsion alone is mainly used with very nonpolar liquids.

[0015] In the spirit of this invention, the defining term "antioxidant" is understood to be a chemical substance that slows down or completely prevents the oxidation of other substances. The antioxidant primarily functions as a radical catcher, inactivating radical-initiated decomposition processes and preventing the oxidative decomposition of contained organic compounds. The antioxidant is added to the formulation in the bonding region to enhance the stability of the cured polymer under harsh operating conditions. These harsh conditions may include, for example, high temperatures in the presence of atmospheric oxygen, which can lead to radical decomposition chains. Such radical decomposition chains are often interrupted or significantly delayed by the antioxidant, which is achieved, for example, by the contained antioxidant, such as a sterically hindered phenol group, forming an extremely inert and stabilized radical, thereby preventing the radical from moving further to another polymer group; these are typically referred to as primary antioxidants. Other types of antioxidants may include, for example, reducing agents that are oxidized before the substance to be protected, and these can be combined. Similarly, so-called secondary antioxidants can be added, including, for example, phosphite compounds, thioester antioxidants, or amino-based systems that protect polymer chains from oxidative attack by destroying peroxides.

[0016] In the context of the present invention, the defined term "organosilane" is understood to be a chemical substance having a silyl group containing at least one organic residue and one to three hydrolyzable substituents or hydroxyl groups. Hydrolyzable groups are, for example, alkoxy groups. This can be an oligomer ethylene glycol chain or an acetoxy functional group. The reactive silane group is a completely or partially hydrolyzed alkoxysilane group, which then forms a silanol group. There are many types of such organosilanes, which differ especially in the structure of the organic residue from each other and are characterized by their chemical structure. Examples include hydroxysilane, isocyanatosilane, aminosilane, thiolsilane, vinylsilane, each having one organic chain between the silyl group and at least one other functionality. Of course, there are also organosilanes having more than one functionality, an example of which is aminosilane containing a secondary amino group and a primary amino group and organoalkoxysilane having at least one hydroxyl group (OH), isocyanate group, amino group or vinyl group in the organic fraction.

[0017] It is possible to classify organosilanes into the following groups with respect to the functionality contained: - Without additional functionality (organic chain), for example octyltrimethoxysilane, OCTMO, - Primary amino functionality, for example 3-aminopropyltrimethoxysilane, AMMO, - Secondary amino functionality, for example N-(n-butyl)-3-aminopropyl-trimethoxysilane, - Diamino functionality, for example N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, DAMO, - Epoxy functionality, for example 3-glycidyloxy-propyl-trimethoxysilane, GLYMO, - Thio functionality, for example 3-mercaptopropyl-trimethoxysilane, MTMO, - Methacryl functionality, for example 3-methacryloxypropyltrimethoxysilane, MEMO, - Vinyl functionality, for example vinyltrimethoxysilane, VTMO.

[0018] The above-mentioned commercially available chemical substances in each group are merely examples, and the groups are not limited thereto.

[0019] In the context of the present invention, the defined term "thermal conductivity filler" is understood to be a chemical substance supplied to the formulation to have thermal conductivity while ensuring filling. General thermal conductivity fillers include: - Metals, however, since such metals have conductivity, they are often not suitable for use. - Aluminum oxide / hydroxide, and - Magnesium oxide / hydroxide, and Diamond, carbon nanotubes, aluminum nitride (AlN), boron nitride (BN), graphite.

[0020] In the context of the present invention, the defined term "catalyst" is understood to be a chemical substance that increases the rate of a reaction or lowers the activation energy of the reaction without being consumed in the reaction by forming an intermediate stage between the catalyst and the reactants.

[0021] The high heat resistance contact filler according to the present invention consists of component A and component B. Component A 1. A) A polyacrylate-based silane-functional prepolymer or a mixture of silane-functional prepolymers having at least one polyacrylate-based silane-functional prepolymer. 2. A) A plasticizer that is a multifunctional carboxylic acid ester. 3. A) A wetting and dispersing additive having at least one amine value greater than 20 mg KOH / g measured based on DIN 19645. 4. A) A mixture consisting of functional organosilanes. 5. A) A mixture of ZnO and another thermal conductivity filler or a plurality of thermal conductivity fillers. and further Component B 1.B) Plasticizers that are multi-functional carboxylic acid esters, 2.B) Wet dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN19645, 3.B) Thermally conductive fillers or mixtures of multiple thermally conductive fillers, 4.B) Water; 5.B) organometallic catalyst, 6.B) Antioxides or mixtures of multiple antioxidants It has, The volume mixing ratio of component A to component B is between 1:1 and 10:1.

[0022] The contact filler according to the present invention exhibits surprisingly high heat resistance. Surprisingly, the temperature resistance of the technology is greatly improved by using a carefully selected combination of silane-modified prepolymers and antioxidants, making it suitable and recommended for high-temperature applications. Similarly, surprisingly, it was possible to obtain the appropriate viscosity of the contact filler according to the present invention. The polyacrylate-based silane-functionalized prepolymer of component A itself has extremely high viscosity, so there was a risk that the desired viscosity could not be obtained. Contrary to expectations, the contact filler according to the present invention exhibits the desired properties, namely good heat resistance, good heat transfer performance, and viscosity suitable for the application, making it usable at high operating temperatures.

[0023] In an advantageous developmental embodiment of the high heat-resistant contact filler, the mixture of silane-functionalized prepolymers further comprises at least one polyurethane and / or polyol / diol-based silane-functionalized prepolymer.

[0024] In the spirit of the present invention, the general term for silane-functionalized prepolymers includes compounds having the following formula:

[0025] [ka]

[0026] In the foregoing formula, A is the backbone of a polymer or prepolymer (German: Rueckgrat), and this backbone is based on - a polyol / diol (e.g., polyether polyol / polyether diol, polypropylene glycol), - has a telechelic polyacrylate, or - can also be a prepolymer based on different technologies, such as a polyurethane-modified prepolymer, which is further modified with an alkoxy-protected silane group in another reaction step.

[0027] In the context of the present invention, the substituents R , R 2 and R 3 can be chemical groups, and at least R 1 and R 2 are alkoxy groups, and R 3 is an alkoxy group or an alkyl group.

[0028] In the context of the present invention, the alkyl group is understood to be a C1-C 10 -alkyl group. In the context of the present invention, C1-C 10 -alkyl includes a straight-chain or branched saturated hydrocarbon group having from 1 to 10 carbon atoms. These include, in particular, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, 2,2-dimethylpropyl, n-hexyl, iso-hexyl, 2-ethylhexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, n-nonyl, n-decyl, etc.

[0029] In the context of the present invention, the alkoxy group is understood to be an O-C1-C 10 -alkyl group. The definition of C1-C 10 -alkyl is as described above.

[0030] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, the alkoxy group is selected from OCH3 and OCH2CH3, and the alkyl group is CH3.

[0031] In yet another particularly advantageous development of the high heat-resistant contact filler, the alkoxy group is OCH3 and the alkyl group is CH3.

[0032] In yet another advantageous developmental embodiment of high heat-resistant contact fillers, silane-functionalized prepolymers or mixtures of silane-functionalized prepolymers are selected from the following groups: - Group A

[0033] This group consists of polyol / diol-based (German: Rueckgrat) prepolymers and is known by the following chemical names: silyl-modified polymers (SMPs), modified silane polymers, MS polymers, and silane-terminated polymers.

[0034] Commercially available prepolymers belonging to this group include, for example, These are dimethoxysilane MS polymer S (e.g., S303H) and strong dimethoxysilane MS polymer SAX (e.g., SAX350).

[0035] The most preferred high heat-resistant contact filler is the prepolymer of formula A-1:

[0036] [ka]

[0037] - Group B The group comprises silane-functionalized prepolymers having a telechelic polyacrylate as a backbone.

[0038] A commercially available prepolymer belonging to this group is, for example, Kaneka XMAP SA (e.g., Kaneka XMAP SA100).

[0039] The most preferred high heat-resistant contact filler is the prepolymer of formula B-1:

[0040] [ka] In the formula, R 1 It is H, C1-C6-alkyl, R 2 It is H, C1-C6-alkyl.

[0041] - Group C Group C comprises a prepolymer containing urethane groups, with the polymer backbone itself being a PU prepolymer. The polyol used in the backbone may be a polyether polyol as described, but other "polyols" are also possible.

[0042] The prepolymer is known by the following chemical names: silane-terminated polyurethane (SPU or STPU), silane-terminated PU, and silane-modified PU.

[0043] Commercially available prepolymers belonging to this group include, for example, polymer ST (e.g., polymer ST44) and geniosil STP-E (e.g., geniosil STP-E30).

[0044] In yet another advantageous developmental embodiment of high heat-resistant contact fillers, one or more silane-functionalized prepolymers are selected from the following group: SAX350, SAX015 (Group A) XMAP SA120S (Group B).

[0045] In yet another advantageous developmental aspect of high heat-resistant contact fillers, the plasticizer is a multi-functional carboxylic acid ester.

[0046] In yet another advantageous developmental aspect of the high heat-resistant contact filler, the plasticizer of component A is a trifunctional carboxylic acid ester.

[0047] In yet another advantageous developmental aspect of the high heat-resistant contact filler, the plasticizer of component A is a triester of trimellitic acid.

[0048] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, the plasticizer of component B has a trifunctional carboxylic acid ester.

[0049] In the spirit of this invention, phthalate esters such as diethylhexyl phthalate or dioctyl phthalate can be used as plasticizers. However, because phthalate esters have some adverse effects on the human body, they are currently on the list of substances of very high concern in the ECHA's SVHC list. Alkyl sulfonate esters and citric acid-based plasticizers, such as triethyl citrate, or adipic acid-based plasticizers, such as diethylhexyl adipate or diethyloctyl adipate, can be used as alternatives to phthalate esters.

[0050] The selection of a suitable plasticizer should be based on the function of the plasticizer in the high heat-resistant contact filler according to the present invention, and it should be noted that the choice of plasticizer may not be exactly the same as when using plasticizers in other functional groups. The plasticizer in the high heat-resistant contact filler according to the present invention has the following problems: - To reduce the viscosity of a liquid component.

[0051] Generally, silyl functionalized prepolymers are high-viscosity raw materials, even when low-viscosity systems are used to form the compound. However, the degree of filling achieved by thermally conductive fillers is directly related to the mixed viscosity of the liquid components. For this reason alone, to obtain the required degree of filling with thermally conductive fillers, it is necessary to add low-viscosity materials that reduce the mixed viscosity of the liquid components as much as possible, so that the viscosity of the finished compound does not become too high for use.

[0052] - Increased flexibility in the cured product Due to the extremely high filler content, the polymer network structure loses its degrees of freedom and, while highly flexible in the unfilled state, the matrix with high elongation at break gradually loses its flexibility, and generally the elongation at break drops to a very low value. By using a plasticizer, the plasticizer molecules not only adhere between the polymer chains as defined above, but ideally form a miscible layer between the filler molecules and the polymer chains. In addition, this greatly increases the degrees of freedom of the polymer chains, which are strongly constricted by the filler molecules, resulting in better internal wetting of the filler.

[0053] Generally, silane-functionalized prepolymers have high molecular weights, often due to their long (pre)polymer backbone. This backbone strongly separates the crosslinking points from each other, forming a coarse, flexible network structure suitable, for example, for flexible adhesives and / or sealants. As mentioned in the first point, the viscosity of the silane-functionalized prepolymer is extremely important in its use; therefore, only low-viscosity types are generally considered suitable for use. However, a higher molecular weight backbone also leads to increased viscosity of the prepolymer, so generally, low molecular weight silane-functionalized prepolymers are more suitable for use. Naturally, these prepolymers exhibit higher crosslinking density, and consequently higher mechanical properties and lower flexibility, further enhanced by the high packing effect mentioned above. Attempts are made to compensate for this not only by using plasticizers and utilizing a predetermined "plasticizer effect" between the cured prepolymer and the filler molecules (see the second point), but also by minimizing the volume fraction of the prepolymer used. This naturally results in the formation of an incompletely formed polymer network structure where not all polymer chains are completely crosslinked. As a result, a rough, elongated polymer network structure is formed that at least partially offsets the drawbacks of the low molecular weight silane-functionalized prepolymers used, and the network structure is adapted to be more flexible, have a lower molecular weight content, and exhibit lower mechanical properties, which may also allow for the use of long-chain silane-functionalized prepolymers.

[0054] Considering the embodiments described above, the following plasticizers are found to be particularly suitable for the high heat-resistant contact filler according to the present invention: Oxsoft3G8:CAS94-28-0 - Triethylene glycol-di-(ethyl 2-hexanoate) - 2,2'-Ethylenedioxydiethylbis(ethyl 2-hexanoate) CereplasL810TM:CAS90218-76-1 - 1,2,4-Benzenetricarboxylic acid, mixed decyltryesters and octyltryesters OxsoftTOTM LE:CAS3319-31-1 - Tris(2-ethylhexyl)benzol-1,2,4-tricarboxylate - Trioctyltrimeritate.

[0055] In another advantageous developmental embodiment of high heat-resistant contact fillers, component A has an antioxidant or a mixture of multiple antioxidants. Examples of these can be found in the product lines of general antioxidant manufacturers, such as ADKStab® from Adeka Polymer Additives.

[0056] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, the wetting dispersion additive has at least a functional amino group and optionally may also contain an acidic group such as a carboxylate group or a phosphorus group.

[0057] Particularly preferred are: Disperbyk2157 or Byk W969.

[0058] The commonality between Disperbyk2157 and Byk W969 lies in the presence of amino groups in the wet dispersion additive, defined by at least the amine value according to DIN16945. Naturally, other functional groups such as phosphorus groups or carboxylate groups can be optionally included to produce similar surfactant effects. In addition, the wet dispersion additive can optionally contain an acid value measured according to DIN EN ISO2114.

[0059] Of particular importance is a wet dispersion additive having an amine value of at least >20 mg KOH / g, and optionally an acid value.

[0060] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, component A comprises a mixture of functional organosilanes.

[0061] In the spirit of this invention, the terms used here are understood to be monofunctional organosilanes and polyfunctional organosilanes. Polyfunctional organosilanes are oligomers or pre-condensed silanes that have a high functional density in their oligomer form, which not only allows them to react more rapidly but also increases the local crosslinking density of the polymer to be cured or enables better bonding of the adhesive to the surface.

[0062] All of the aforementioned organosilanes first function as crosslinking agents. They increase the crosslinking density of the prepolymer by being incorporated into the network structure of the silane-functionalized prepolymer. The functional groups they contain determine the function of the formulation.

[0063] In yet another advantageous development of the high heat-resistant contact filler, the following organosilanes are used: The following organosilanes, including their functional properties, are important in the formulation: a) Amino-functional organosilanes These organosilanes generally have the effect of promoting silane condensation reactions and are used as co-catalysts in addition to their general properties. Furthermore, these organosilanes, like epoxy-functionalized organosilanes, have an adhesion-improving effect on various substrates.

[0064] In yet another particularly advantageous developmental aspect of high heat-resistant contact fillers - AMMO or - Oligomers, such as pre-condensed silanes containing amino groups in the Dynasylan® SIVO series. Use this.

[0065] b) Vinyl-functional organosilane The vinyl-functionalized organosilane primarily has a drying effect. The fillers and plasticizers used in the manufacturing step have a predetermined residual moisture or water content. Although this residual moisture or water content is extremely low, unexpected silane condensation can occur over time, significantly increasing viscosity and reducing applicability, thus negatively impacting the storage stability of the silane-functionalized prepolymer. To dry the mixture, the vinyl-functionalized organosilane is added to the formulation, drying the fillers and other components in situ. The small amount of unreacted vinyl-functionalized organosilane remaining in the formulation allows for proper storage stability of the formulation without requiring special equipment such as manufacturing components under inert gas or pre-drying fillers in a double layer or special dryer.

[0066] In yet another particularly advantageous developmental embodiment of high heat-resistant contact fillers, VTMO is used.

[0067] c) Epoxy-functional organosilanes In addition to their generally described properties, epoxy silanes are added to formulations for other interesting properties. On the one hand, crosslinking can also be achieved through the reaction of epoxy-functionalized silanes and amino-functionalized silanes with each other (apart from silane condensation). Furthermore, epoxy silanes are known for their excellent adhesion-improving properties across a wide range of surface chemical structures (from polymer surfaces to metal surfaces), which helps in obtaining a well-balanced product property profile.

[0068] In yet another particularly advantageous development of the high heat-resistant contact filler, the mixture of functional organosilanes comprises at least one amino-functional organosilane, vinyl-functional organosilane, or epoxy-functional organosilane.

[0069] In yet another particularly advantageous development of the high heat-resistant contact filler, the mixture of functional organosilanes comprises at least two organosilanes selected from the group consisting of amino-functional organosilanes, vinyl-functional organosilanes, and epoxy-functional organosilanes.

[0070] In yet another particularly advantageous development of the high heat-resistant contact filler, the mixture of functional organosilanes comprises at least one amino-functional organosilane and a vinyl-functional organosilane.

[0071] In yet another particularly advantageous development of high heat-resistant contact fillers, the mixture of functional organosilanes comprises amino-functional organosilanes, vinyl-functional organosilanes, and epoxy-functional organosilanes.

[0072] In yet another particularly advantageous development of high heat-resistant contact fillers, at least one of the functional organosilanes is an oligomer silane.

[0073] GLYMO is used in yet another particularly advantageous development embodiment of high heat-resistant contact fillers.

[0074] In yet another particularly advantageous development embodiment of the high heat-resistant contact filler, zinc oxide is forcibly used as the filler.

[0075] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, a thermally conductive filler selected from the group consisting of Al(OH)3 and Al2O3 is used in addition to ZnO. In yet another advantageous developmental embodiment of the high heat-resistant contact filler, the total amount of filler in components A and B is 80 to 95% by weight, preferably 88 to 93% by weight, and more preferably 88 to 90% by weight, and accordingly the proportion of ZnO in the filler mixture is 10 to 30% by weight, preferably 15 to 25% by weight, and more preferably 15 to 20% by weight.

[0076] In yet another advantageous development of the high heat-resistant contact filler, at least one of the thermally conductive fillers preferably has a hydrophobic surface coating and / or surface functionalization.

[0077] As is well known, silane-functionalized prepolymers react in the presence of water and undergo condensation reactions. Generally, water in these reactions is introduced primarily by fillers. As detailed above, the fillers are at least partially covered with water on their surface by moisture. Furthermore, capillary action of the filler molecules stores water in pores and cracks.

[0078] As in the embodiments of the present invention, the filler can be dried by adding a vinyl-functional organosilane. However, in such cases, the required amount of vinyl-functional organosilane must be adjusted according to the moisture content of the filler. If the filler is not sufficiently dried, the storage stability of the final compound is affected, particularly by the slow increase in viscosity of the liquid component due to the slow condensation reaction of the polymer.

[0079] This can be avoided through formulation by using partially hydrophobic fillers. Hydrophobization of fillers is a process in large-scale industrial applications, in which the filler is coated with surfactant molecules or polymers as much as possible. For this purpose, depending on the filler, fatty acids, organosilanes, organotitanates, and functional or non-functional polymers can be used, making both chemiadsorption and physiadsorption of the coating additive on the surface a practical possibility for surface functionalization.

[0080] Because the extremely thin coating makes the filler surface hydrophobic, only a very small amount of water due to humidity accumulates in the filler, and therefore the residual moisture content of the filler is minimal. This leads to achieving an effect similar to the aforementioned wetting and dispersion additives, which are not necessary in such cases, through the optimal selection of the coating.

[0081] In yet another advantageous developmental embodiment of the high heat-resistant contact filler, component B comprises a catalyst.

[0082] In yet another particularly advantageous development of high heat-resistant contact fillers, the catalyst is an organometallic complex. It is possible to use all commercially available organometallic catalysts. One example is a tin complex, but the present invention is not limited thereto. Preferred suitable catalysts include: dibutyltin dilaurate (DBLT), dioctyltin dilaurate, oxides thereof such as dibutyltin oxide and dioctyltin oxide, or other tin complexes or dioctyltin / dibutyltin silane complexes in which ligands have been additively exchanged, such as dioctyltin diacetylacetonate.

[0083] In yet another particularly advantageous development of high heat-resistant contact fillers, the catalyst may be a co-catalyst base such as an amine as a proton acceptor. These are generally used in formulations as amino-functional organosilanes and are outlined as organosilanes.

[0084] In yet another particularly advantageous developmental embodiment of high heat-resistant contact fillers, the catalyst is an acid catalyst system.

[0085] In yet another particularly advantageous development of the high heat-resistant contact filler, the catalyst is silicon-free.

[0086] This method has the advantage of ensuring that volatile compounds do not deposit on the surface around the active ingredient in the system. This avoids, on the one hand, the impairment of the adhesion of the coating or adhesive layer on the contaminated surface. On the other hand, electrical contacts are also protected.

[0087] The present invention will be described below with reference to examples, but these examples are not intended to limit the present invention. Example 1: Manufacturing of Component A and Component B The raw materials listed in Table 1 were measured into speed mixer cups and pre-mixed for 30 seconds at a rotation speed of 2000 rpm (revolutions per minute) to obtain a homogeneous composition. Then, the composition was degassed for 3 minutes at 900 rpm in a vacuum speed mixer. All of the aforementioned compositions were prepared as described above.

[0088] As can be seen in Table 1, formulations F1 through F4 each lack one component compared to the standard formulation F. Compositions F1 and F2 use only one polymer (XMAP or SMP). Formulation F3 lacks ZnO, and F4 lacks an antioxidant.

[0089] [Table 1]

[0090] The raw materials listed in Table 2 were measured into speed mixer cups and pre-mixed for 30 seconds at a rotation speed of 2000 rpm (revolutions per minute) to obtain a homogeneous composition. Then, the composition was degassed for 3 minutes at 900 rpm in a vacuum speed mixer. All of the aforementioned compositions were prepared as described above.

[0091] [Table 2]

[0092] The volume mixing ratio of component A to component B is 10:1. B is a so-called booster component that produces two effects: - On the one hand, by uniformly introducing moisture to component A, component A hardens uniformly. In the absence of component B, component A hardens from the outside inward upon contact with moisture. In typical large-area applications within a single module, the extremely long diffusion pathways formed and the extremely small contact surface with ambient air with component A alone mean that some of the component remains ineffective for a long time in the center of the high-temperature resistant contact filler introduced over a large area.

[0093] - On the other hand, the addition of a catalyst accelerates the condensation reaction of silane-functionalized molecules.

[0094] Experiment 1: Temperature stability testing using TGA measurement. Small amounts of each material, cured at room temperature for 7 days, were heated in a crucible at a heating rate of 10 K / min, and the relationship between the mass loss of the sample and the temperature was determined.

[0095] Individual mass losses were determined at 280°C, 340°C, and 370°C.

[0096] [Table 3]

[0097] As can be seen in Table 3, formulation R is better than formulations F2 and F4. In contrast, formulation F1 exhibits better thermal behavior than the reference formulation and is more preferable in terms of thermal properties. However, because XMAP has an extremely high viscosity, this formulation can no longer be used because the viscosity of the blended components is too high and no similar low-viscosity prepolymer is commercially available.

[0098] Furthermore, formulation F3 shows slightly better values ​​than the standard formulation at 280°C and 370°C. However, it cannot be used in the same way due to poor application behavior and sedimentation behavior. As mentioned above, zinc oxide does not have a significant effect on temperature stability, but it has a significant effect on application behavior and sedimentation behavior.

[0099] In summary, standard formulation R exhibits the best properties on average, making it preferable to use.

[0100] Experiment 2: Mechanics Test In another experiment, the compounds were cured at room temperature for 7 days, followed by curing at a constant temperature of 150°C for several days, after which the mechanics of the aforementioned compounds were examined. Here, samples for tensile strength were prepared, cured, and measured according to DIN EN ISO 527, recording their respective tensile strengths and elongations at break.

[0101] Subsequently, the measured values ​​after curing at room temperature were compared with the values ​​after curing at 150°C for 7 days, and the relative dynamics to the initial values ​​were calculated.

[0102] [Table 4]

[0103] Formula F1 exhibited the best heat-curing behavior, and also showed the best tensile strength and elongation at break after heat curing. However, as mentioned above, unfortunately, this formula is too viscous to be used in this field.

[0104] Although compound F2 exhibits excellent viscosity, it showed strong embrittlement and collapse under temperature curing conditions, and therefore must be classified as unsuitable in this context.

[0105] As the curing of formulation F3 demonstrates, the addition of antioxidants is essential. Without antioxidants, similarly strong embrittlement occurs, as well as loss of elongation at break, which is important in use.

[0106] Similar to the TGA test, the addition of zinc oxide does not affect curing behavior, but it is considered essential to include it in commercially available formulations for better application and settling behavior.

Claims

1. A high heat-resistant contact filler comprising component A and component B, The aforementioned component A is 1. A) A polyacrylate-based silane-functional prepolymer or a mixture of silane-functional prepolymers having at least one polyacrylate-based silane-functional prepolymer.

2. A) Plasticizers that are multi-functional carboxylic acid esters, 3. A) A wet dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN 19645.

4. A) A mixture consisting of functional organosilanes, 5. A) ZnO and another thermally conductive filler or a mixture of multiple thermally conductive fillers It has, and further The aforementioned component B is 1. B) Plasticizers that are multi-functional carboxylic acid esters, 2. B) Wet dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN 19645, 3. B) Thermally conductive filler or a mixture of multiple thermally conductive fillers, 4. B) water; 5. B) organometallic catalyst, 6. B) Antioxidants or mixtures of multiple antioxidants It has, A highly heat-resistant contact filler characterized in that the volume mixing ratio of component A to component B is 1:1 to 10:

1.

2. The high heat-resistant contact filler according to claim 1, characterized in that the mixture of silane-functionalized prepolymers further comprises at least one polyurethane and / or polyol / diol-based silane-functionalized prepolymer.

3. The high heat-resistant contact filler according to claim 1 or 2, characterized in that the plasticizer of component A is a trifunctional carboxylic acid ester.

4. The high heat-resistant contact filler according to any one of claims 1 to 3, characterized in that component A has an antioxidant or a mixture of multiple antioxidants.

5. The high heat-resistant contact filler according to any one of claims 1 to 4, characterized in that the mixture of functional organosilanes has at least one amino-functional organosilane, vinyl-functional organosilane, or epoxy-functional organosilane.

6. The high heat-resistant contact filler according to any one of claims 1 to 4, characterized in that the mixture of functional organosilanes has at least two organosilanes selected from the group consisting of amino-functional organosilanes, vinyl-functional organosilanes, and epoxy-functional organosilanes.

7. The high heat-resistant contact filler according to any one of claims 1 to 6, characterized in that at least one of the functional organosilanes is an oligomer silane.

8. The aforementioned thermally conductive filler is Al(OH) ３ and Al ２ O ３ A high heat-resistant contact filler according to any one of claims 1 to 7, characterized in that it is selected from a group consisting of the following.

9. The aforementioned mixture of thermally conductive fillers is Al(OH) ３ and Al ２ O ３ A high heat-resistant contact filler according to any one of claims 1 to 8, characterized by having the following:

10. The high heat-resistant contact filler according to any one of claims 1 to 9, characterized in that at least one of the thermally conductive fillers has a surface coating and / or surface functionalization.

11. The high heat-resistant contact filler according to any one of claims 1 to 10, characterized in that the total amount of the filler in components A and B is 80 to 95% by weight, and the proportion of ZnO in the mixture of the fillers is 10 to 30% by weight.

12. The high heat-resistant contact filler according to any one of claims 1 to 11, characterized in that the total amount of the filler in components A and B is 80 to 93% by weight, and the proportion of ZnO in the mixture of the fillers is 15 to 25% by weight.

13. The mixture of the silane-functionalized prepolymer in an amount of 3 to 10% by weight, wherein the polyacrylate-based silane-functionalized prepolymer accounts for up to 50% by weight. 0.5 to 5% by weight of the aforementioned antioxidant, 3 to 15% by weight of the plasticizer, 0.2 to 2% by weight of the wetting dispersion additive, 0.5 to 5% by weight of the organosilane, and A mixture comprising 78 to 93% by weight of ZnO and the other thermally conductive fillers or a mixture of the plurality of thermally conductive fillers, wherein the proportion of ZnO in the mixture of fillers is 10 to 30% by weight, A high heat-resistant contact filler according to any one of claims 1 to 12, characterized by having the following:

14. A mixture of 5 to 9% by weight of the silane-functionalized prepolymer, wherein the polyacrylate-based silane-functionalized prepolymer accounts for up to 50% by weight. 0.5 to 1.5% by weight of the antioxidant, 3 to 5% by weight of the plasticizer, 0.5 to 1.5% by weight of the wet dispersion additive, 0.5 to 1.5% by weight of the organosilane, and A mixture comprising 80 to 93% by weight of ZnO and the other thermally conductive fillers or a mixture of the plurality of thermally conductive fillers, wherein the proportion of ZnO in the mixture of fillers is 15 to 25% by weight, A high heat-resistant contact filler according to any one of claims 1 to 13, characterized by having the following:

15. A high heat-resistant contact filler according to any one of claims 1 to 14, characterized in that it does not contain silicon.

16. Use of a high heat-resistant contact filler according to any one of claims 1 to 15 in an electronic component subjected to a high thermal load.

17. Use of the high heat-resistant contact filler according to any one of claims 1 to 15 in a battery system having a complex battery structure.

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