Injectable heat-contacting fillers and use of said heat-contacting fillers in large-area components

Abstract

The present invention relates to an injectable thermal contact filler comprising component A and component B. Component A is a silane-functionalized prepolymer or a mixture of silane-functionalized prepolymers, the silane-functionalized prepolymer being polyurethane, polyol / diol or polyacrylate-based, and comprising a plasticizer which is a multi-functionalized 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 functionalized organosilanes, ZnO, and yet another thermally conductive filler or a mixture of multiple thermally conductive fillers. Component B comprises a plasticizer which is a multi-functionalized 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, and an organometallic catalyst. 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. For thermal contact between active components and corresponding heat supply or heat dissipation means, fixed mechanical contact is typically formed by screws, clamps, or material bonding by soldering or welding. Mechanical fixing has the advantage of the bond being detachable. However, heat conduction between active components occurs only through a limited number of contact points. Because there is an air layer between active components, which is a very poor thermal conductor, the generated heat is only dissipated incompletely. Therefore, to improve heat conduction, a thermally conductive material is introduced into the gap between active components, i.e., between heat-generating components and heat-dissipating components. This material has two roles: it conducts heat and at the same time bonds the active components together. [Background technology]

[0002] Such thermally conductive materials are known in the latest technology in the form of thermally conductive pastes. On the one hand, thermally conductive pastes are used in microelectronics to bond extremely small components.

[0003] For use over small areas, such a thermally conductive paste is generally applied to individual active components. Applying force to the components then joins them together (Grouting).

[0004] In the field of electronics, the surface area to be bonded is extremely small. At the same time, high heat is generated by high-frequency switching intervals, high-pulse integrated circuits, or processors, and to avoid damage to each component and, consequently, to the entire device, heat must be dissipated through a small surface area. Therefore, when selecting a thermal contact filler in this field, the thermal conductivity of the thermal contact filler is particularly important because it is necessary to dissipate high heat from an extremely small surface area.

[0005] The use of a thermally conductive paste to bond large-area components is described in German Patent Application Publication No. 102018102989. The document discloses a silane-functionalized prepolymer-based, reaction-curing thermally conductive paste for use in thermal management of modularly constructed batteries comprising a plurality of interconnected battery cells, for example, in electric vehicles.

[0006] For example, in the case of use over a large area, such as in the batteries of electric vehicles, a thermally conductive paste is applied to a carrier or base plate before fitting in individual batteries or pre-formed battery modules consisting of multiple battery cells, and is compressed to a predetermined layer thickness along with the positioning of the individual batteries or pre-formed battery modules.

[0007] The requirements for heat-contact fillers intended for use over large areas are clearly more complex for the reasons explained below.

[0008] The larger the surfaces to be joined, the greater the force required to join them together. Such highly filled systems, like the aforementioned thermally conductive paste, inherently possess high viscosity, and therefore, during manufacturing, strong force is required to achieve grouting of active components within an acceptable cycle time. However, increasing the applied force does not arbitrarily speed up the cycle time. Pre-formed battery modules, including individual batteries or multiple battery cells intended for use in electric vehicles, also have limited force tolerance, leading to strain, immediate electrochemical structural damage, or other defects, which can significantly reduce the lifespan of the battery or storage system, and consequently, the vehicle.

[0009] The aforementioned drawbacks of methods involving the grouting of active components can be avoided by using a so-called injection method. In the injection method, the contact filler is injected rather than applied. This significantly speeds up the assembly of a battery, for example, a battery containing multiple battery cells, in the manufacturing step, while simultaneously ensuring a substantial reduction in the risk of damaging the battery cells compared to the conventional process described above.

[0010] For the injection method to be usable, attention must be paid to predetermined gaps in the structure and process. By injecting a thermal contact filler into these gaps, the gaps are filled completely and air-free, thereby ensuring extremely good thermal conductivity of the parts to be joined. To completely fill the gaps with thermal contact filler and air-free, injection from one or more injection points is necessary. This ensures that all air in the gaps is released. The injection step must be configured so that no air is contained during injection. This can be achieved by flow simulation or by appropriately designing the injection step. This can be achieved, on the one hand, by changing the type and location of the injection openings, and on the other hand, by precisely changing the injection pressure at one or more injection openings. The injection process is terminated after the thermal conductive paste has exited through the air outlet holes and no more air is contained in the gaps.

[0011] However, the requirements for thermal contact fillers that are suitable for the injection step are high. In particular, thermal contact fillers need to have a suitable viscosity. For example, if the viscosity is too high, such as the thermal conductive paste known from German Patent Application Publication No. 102018102989 and other prior art, strong back pressure will be generated during injection, requiring a strong pump and injection pressure. When adapted for use over large areas, the requirements for the injection pump become extremely high, and in some cases, it may not be feasible. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] German Patent Application Publication No. 102018102989 [Overview of the project] [Problems that the invention aims to solve]

[0013] For example, new battery concepts in electromobility are increasingly reliant on functional thermal management, and the demand for thermal contact fillers, especially for use over large areas, is steadily increasing. Therefore, the object of the present invention is to provide a thermal contact filler with desired properties that enables high-capacity and large-area use in the injection step while simultaneously being able to withstand high heat transfer. [Means for solving the problem]

[0014] This problem of the present invention has been remarkably solved by the injectable heat-contact filler having the features of claim 1. Advantageous developments of the concept of the present invention are subject to the conventional claims. Yet another advantageous development of the injectable heat-contact filler according to the present invention is seen in the description and examples.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 fully 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.

[0021] 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 propyltrimethoxysilane, MEMO, - Vinyl functionality, for example vinyltrimethoxysilane, VTMO.

[0022] The commercially available chemicals mentioned above in each group are merely examples, and the groups are not limited to these.

[0023] In the spirit of this invention, the defining term "thermal conductive filler" is understood to refer to a chemical substance supplied to a compound to ensure filling while simultaneously possessing thermal conductivity. Typical thermal conductive fillers include: - Metals, however, these metals are often unsuitable for use because they are electrically conductive. - Aluminum oxide / aluminum hydroxide, and - Magnesium oxide / magnesium hydroxide, and Diamond, carbon nanotubes, aluminum nitride (AIN), boron nitride (BN), graphite.

[0024] In the spirit of this invention, the defining term "catalyst" is understood to be a chemical substance that increases the rate of a reaction or lowers the activation energy of a reaction without consuming itself in the reaction by forming an intermediate step between the catalyst and the reactant.

[0025] The injectable heat-contact filler according to the present invention comprises component A and component B, Component A is, 1.A) A silane-functionalized prepolymer or a mixture of silane-functionalized prepolymers, wherein the silane-functionalized prepolymer is polyurethane, polyol / diol, or polyacrylate-based. 2.A) Plasticizers that are multi-functional carboxylic acid esters, 3.A) Wet dispersion additive having at least one amine value greater than >20 mg KOH / g as measured according to DIN19645, 4.A) A mixture consisting of functional organosilanes, 5.A) ZnO and yet another thermally conductive filler or a mixture of multiple thermally conductive fillers, It has, and further 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 DIN19645, 3.B) Thermally conductive fillers or mixtures of multiple thermally conductive fillers, 4.B) Water, and 5.B) Organometallic catalyst It has, The volume mixing ratio of component A to component B is between 1:1 and 10:1.

[0026] The injectable heat-contact filler according to the present invention exhibits processing properties that are remarkably essential for use in the injection step. Remarkably, it has been found that the addition of zinc oxide to the mixture brings about a remarkable change in the processing properties essential for use in injection.

[0027] For developers in this field, it is known that to liquefy a thermally conductive composition, the ratio of surface area to volume decreases as particle size increases; therefore, on the one hand, it is necessary to select a formulation with larger particles. On the other hand, the composition should be composed of nearly round particle sizes. This contributes to lowering viscosity because, in a highly packed system, particles can pass through each other like bearings rather than binding together. However, such compositions generally have drawbacks in application and injection. A major drawback is the high tendency of such compositions to settle, which significantly affects storage stability by forming a high-density base layer during storage and transport, causing the packing material to settle, separate, and not completely aggregate back into a suspension even with strong shear. Furthermore, in the injection step, such compositions have the disadvantage that the high pump pressure required causes segregation of solid and liquid components, making continuous and reproducible injection impossible.

[0028] To avoid this drawback, thixotropes are generally added to the composition to increase the concentration of the liquid phase through particle interactions or, for example, gelation. However, by adding thixotropes, it becomes impossible to obtain a self-flowing formulation that is as liquid as possible and can be injected. Instead, it results in a highly viscous paste that prevents sedimentation but is unsuitable for injection.

[0029] Surprisingly, however, it was found that partially substituting the thermally conductive filler with zinc oxide significantly improved the settling behavior and injectability of the filler without significantly affecting its viscosity. Since zinc oxide itself has high thermal conductivity, substitution with zinc oxide does not cause a decrease in thermal conductivity. Therefore, this invention provides an injectable thermal contact filler suitable for use over large areas that does not have the aforementioned drawbacks.

[0030] In an advantageous developmental embodiment of the injectable thermal contact filler, a silane-functionalized prepolymer or a mixture of silane-functionalized prepolymers is used, wherein the silane-functionalized prepolymer is polyurethane, polyol / diol, or polyacrylate-based.

[0031] In an advantageous developmental embodiment of the injectable thermal contact filler, component A comprises only one polyurethane-based silane-functionalized prepolymer.

[0032] In the spirit of the present invention, the general term for silane-functionalized prepolymers includes compounds having the following formula:

[0033] [ka]

[0034] In the aforementioned formula, A is the polymer or prepolymer skeleton (German: Rueckgrat), and this skeleton is the base - Polyols / diols (e.g., polyether polyols / polyether diols, polypropylene glycols), - having telekinetic polyacrylate, or - may 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.

[0035] In the context of the present invention, the substituents R 10 , 3 , , 1 , ,

[0039] , 2 , , 10 , , ,

[0037] ,

[0040] , , 10 , 10 , 2 , 3 ,

[0036] , 1 , , ,

[0038] , , 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.

[0036] 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 linear 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.

[0037] ​​​​​​​​​​​​​​​ In yet another advantageous developmental embodiment of the injectable heat-contact filler, silane-functionalized prepolymers or mixtures of silane-functionalized prepolymers are selected from the following groups: - Group A

[0041] 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.

[0042] 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).

[0043] The most preferred injectable thermal contact filler is the prepolymer of formula A-1:

[0044] [ka]

[0045] - Group B The group comprises silane-functionalized prepolymers having a telechelic polyacrylate as a backbone.

[0046] A commercially available prepolymer belonging to this group is, for example, Kaneka XMAP SA (e.g., Kaneka XMAP SA100).

[0047] The most preferred injectable thermal contact filler is the prepolymer of formula B-1:

[0048] [ka] In the formula, R 1 It is H, C1-C6-alkyl, R 2 It is H, C1-C6-alkyl.

[0049] - 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.

[0050] The prepolymer is known by the following chemical names: silane-terminated polyurethane (SPU or STPU), silane-terminated PU, and silane-modified PU.

[0051] 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).

[0052] The most preferred injectable thermal contact filler is the prepolymer of formula C-1:

[0053] [ka]

[0054] In yet another advantageous development embodiment of an injectable thermal contact filler, one or more silane-functionalized prepolymers are selected from the following group: SAX350 (Group A) XMAP SA120S (Group B) Polymer ST-61LV (Group C).

[0055] In yet another particularly advantageous developmental embodiment of the injectable heat-contact filler, component A comprises only a silane-functionalized prepolymer of group C, preferably ST-61LV.

[0056] In yet another advantageous developmental embodiment of the injectable thermal contact filler, the plasticizer is a multi-functional carboxylic acid ester.

[0057] 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.

[0058] The selection of a suitable plasticizer should be based on the function of the plasticizer in the injectable heat-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 with other functional groups. The plasticizer in the injectable heat-contact filler according to the present invention has the following challenges: - To reduce the viscosity of a liquid component.

[0059] 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.

[0060] - Increased flexibility in the cured product

[0061] 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.

[0062] 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. Naturally, these prepolymers exhibit higher crosslinking density, and consequently higher mechanical properties and lower flexibility, further enhanced by the high packing density effect mentioned above. This is attempted not only by using plasticizers and utilizing a predetermined "plasticizer curing" 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.

[0063] Considering the embodiments described above, the following plasticizers are found to be particularly suitable for the injectable heat-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

[0064] Most preferred are dicarboxylic acid esters, tricarboxylic acid esters, or polyfunctional carboxylic acid esters. In yet another particularly advantageous development of the implantable heat-contact filler, Oxsoft3G8 is used as a plasticizer.

[0065] In yet another advantageous developmental embodiment of the injectable heat-contact filler, the wet dispersion additive has at least a functional amino group and optionally may also include an acidic group such as a phosphorus group or a carboxylate group.

[0066] Particularly preferred are: Disperbyk2157 or Byk W969.

[0067] 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.

[0068] Of particular importance is a wet dispersion additive having an amine value of at least >20 mg KOH / g, and optionally an acid value.

[0069] In yet another advantageous developmental embodiment of the injectable contact filler, component A has a mixture comprising functional organosilanes.

[0070] 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.

[0071] 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.

[0072] In yet another advantageous development embodiment of the injectable thermal contact filler, the following organosilanes are used: The following organosilanes, including their functional properties, are important in the formulation: a) Amino-functional organosilanes

[0073] 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.

[0074] yet another particularly advantageous development embodiment of an injectable thermal contact filler. - AMMO or - Oligomers, such as pre-condensed silanes containing amino groups in the Dynasylan® SIVO series. Use this.

[0075] b) Vinyl-functional organosilane

[0076] 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.

[0077] In yet another particularly advantageous development embodiment of the injectable thermal contact filler, VTMO is used.

[0078] 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.

[0079] In yet another particularly advantageous development of the injectable heat-contact filler, the mixture of functional organosilanes comprises at least one amino-functional organosilane, vinyl-functional organosilane, or epoxy-functional organosilane.

[0080] In yet another particularly advantageous development of the injectable heat-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. In yet another particularly advantageous development of the injectable heat-contact filler, the mixture of functional organosilanes comprises at least one amino-functional organosilane and a vinyl-functional organosilane.

[0081] In yet another particularly advantageous development of the injectable heat-contact filler, the mixture of functional organosilanes comprises amino-functional organosilanes, vinyl-functional organosilanes, and epoxy-functional organosilanes.

[0082] In yet another particularly advantageous development of the injectable thermal contact filler, at least one of the functional organosilanes is an oligomer silane.

[0083] GLYMO is used in yet another particularly advantageous development embodiment of an injectable thermal contact filler.

[0084] In yet another particularly advantageous development embodiment of the injectable heat-contact filler, zinc oxide is forcibly used as the filler.

[0085] In yet another advantageous developmental embodiment of the injectable thermal contact filler, a thermally conductive filler selected from the group consisting of Al(OH)3 and Al2O3 is used in addition to ZnO.

[0086] In yet another advantageous developmental embodiment of the injectable heat-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.

[0087] In yet another advantageous development of the injectable thermal contact filler, at least one of the thermal conductive fillers preferably has a hydrophobic surface coating and / or surface functionalization.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] In yet another advantageous developmental embodiment of the injectable thermal contact filler, component B comprises a catalyst.

[0093] In yet another particularly advantageous development of the implantable thermal contact filler, 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.

[0094] In yet another particularly advantageous developmental embodiment of the injectable thermal contact filler, the catalyst may be a cocatalytic base such as an amine as a proton acceptor. These are generally used in formulations as amino-functional organosilanes and are outlined as organosilanes.

[0095] In yet another particularly advantageous developmental embodiment of the injectable thermal contact filler, the catalyst is an acid catalyst system.

[0096] In yet another particularly advantageous development embodiment of the injectable thermal contact filler, the catalyst is silicon-free.

[0097] 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.

[0098] The present invention will be described below with reference to examples, but these examples are not intended to limit the present invention.

[0099] Example 1: Preparation 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.

[0100] As can be seen in Table 1, compositions F1 to F4 differ from each other primarily in terms of the type of filler used. Compositions F1 and F2 contain the same amount of the same filler, and F2 further contains fumed silica, which is a synthetically produced colloidal substance having predetermined properties and particle size for use as a filler. This substance consists solely of silicon dioxide particles (SiO2) aggregated into larger units. On the other hand, compositions F3 and F4 have the same filler in different amounts.

[0101] [Table 1]

[0102] Table 2 - Component B 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.

[0103] [Table 2]

[0104] 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 surface area of ​​contact with ambient air with component A alone mean that some of the component remains ineffective for a long time in the center of the injectable heat-contact filler introduced over a large area. - On the other hand, the addition of a catalyst accelerates the condensation reaction of silane-functionalized molecules.

[0105] Experiment 1: Examination of sedimentation behavior, viscosity, and extrusion properties. The reason the sedimentation behavior was determined based solely on the composition of component A is that the deposition problem of component A is slightly larger, and component A is a reactive component. Therefore, the explanation of component B is omitted here. Component B is thought to be non-reactive and contains water and a catalyst necessary for rapidly curing the contact filler according to the present invention.

[0106] After preparing Component A in 100g or 500g batches, the viscosity of compositions F1 to F4 was measured immediately after preparation. The results are summarized in Table 2, row 1 and section 1:

[0107] [Table 3]

[0108] As can be seen, compositions F1 and F3 (see Table 1), which use different amounts of ZnO, have almost the same viscosity immediately after preparation.

[0109] Subsequently, compositions F1 to F4 were transferred to cartridges and stored vertically (upright) at 60°C for one week. This allowed for a rapid simulation of the degradation and sedimentation processes during storage and transport. After one week, the sedimentation behavior of compositions F1 to F4 was determined by determining the viscosity and density of each composition within the cartridge at 60°C. For this purpose, the cartridges were divided into five volumetric regions, and corresponding samples were taken. Sample 1 was taken directly from the top of the cartridge, Sample 3 from the central volumetric region, and Sample 5 from the bottom of the cartridge. Therefore, Samples 2 and 4 represent intermediate measurements in the upper / lower central volumetric regions of each cartridge.

[0110] The viscosity of the extracted sample was measured using a plate-plate rheometer at a shear rate of 10 s⁻¹. Density was measured in a small plastic cup containing approximately 2 ml of the composition, due to its extremely high viscosity. The cup's volume was determined by completely filling it with water and re-weighing it before density measurement. After drying the cup, each component was filled in carefully to avoid air bubbles, and any excess material was removed so that it was flush with the rim of the cup. The filled cup was then re-weighed, and the density was calculated from the mass of the components and the precise volume of the cup. The extrusion from the cartridge was also evaluated by pushing it out and recorded as an impression.

[0111] As can be seen from the results in Table 2, the viscosity progression of composition V1 is equivalent to that of the standard formulations F2 to F4. Settlement behavior, which is related to a 20 to 30% increase in viscosity in the lower volume region compared to the upper volume region, was observed in all formulations and can be correlated with the increase in density at the bottom of the cartridge, although the degree of correlation is not very strong. In formulation F4, strong deposition occurred in the lower region, making it impossible to transfer to the measuring cup without creating bubbles, and therefore it was impossible to measure it properly.

[0112] However, a significant difference in extrudeability was observed between composition V1 and compositions V3 and V4 (the latter without ZnO). This clearly indicates that the injectability of composition V1 was significantly improved by the addition of ZnO.

[0113] In this direct comparison, compositions V3 and V4 had excessively high viscosity, making them extremely difficult to transport. Even composition V2, which is composition 1 with 1.5% fumed silica added to obtain a higher viscosity, showed several times better extrudeability, and the same was true for comparative compositions V3 and V4.

[0114] Experiment 2: Testing for injectability For this experiment, composition V1, which showed the best extrudeability, was compared with composition F3, which does not contain ZnO.

[0115] The movement of the injection front was recorded, and injection tests were performed on a metal dummy with a screw-on Perspex lid to determine the injection time. The gap width was 1 mm, the injection volume was approximately 85 ml, and the dimensions of the injection cavity were 450 mm × 195 mm × 1 mm.

[0116] The Perspex lid was sealed at its edges with a sealant. The Perspex plate included an injection hole and a notch in the sealing rubber on the opposite side of the injection area to release air and drain excess injection material after the test. The Perspex plate was divided into 1 / 3 and 2 / 3 equal injection areas and the total injection length by two adhesive tapes to record intermediate injection times in a reproducible manner.

[0117] First, compositions V1 and V3, containing only component A as shown in Table 1, were prepared. These compositions were then transferred to cartridges in a 10:1 ratio with component B, ensuring no air bubbles were present, and a static mixer (10-24T-MFHX) was installed. The injection of composition V1 + component B and V3 with component B was carried out using a pneumatic cartridge gun through a hole passing through a Perspeck plate. The air pressure was set to the maximum value of 6 bar. The ambient temperature and material temperature were room temperature (approximately 23°C). The results are summarized in Table 3:

[0118] [Table 4]

[0119] The injection of composition V3 + component B was interrupted after 3:00 of the injection time. Complete injection with a cartridge gun was impossible because of its extremely high viscosity and low fluidity, insufficient maximum air pressure for injection, and the risk of the Perspeck plate being damaged by the pressure increase. In contrast, the injectable heat-contact filler (V1 + component B) according to the present invention can be injected very quickly and easily.

Claims

1. An injectable heat-contact filler comprising component A and component B, The aforementioned component A is, 1. A) A silane-functionalized prepolymer or a mixture of silane-functionalized prepolymers, wherein the silane-functionalized prepolymer is polyurethane, polyol / diol, or polyacrylate-based.

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, and 5. B) Organometallic catalyst It has, An injectable heat-contact filler characterized in that the volume mixing ratio of component A to component B is 1:1 to 10:

1.

2. The injectable heat-contact filler according to claim 1, characterized in that component A comprises only a polyurethane-based silane-functionalized prepolymer.

3. The injectable heat-contact filler according to claim 1 or 2, characterized in that the plasticizer is a difunctional carboxylic acid ester.

4. The injectable heat-contact filler according to claim 3, characterized in that the plasticizer is a polyether alcohol-based difunctional carboxylic acid ester.

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

6. The mixture of functional organosilanes is characterized by having at least two organosilanes selected from the group consisting of amino-functional organosilanes, vinyl-functional organosilanes, and epoxy-functional organosilanes, as described in any one of claims 1 to 4.

7. The injectable heat-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 An injectable heat-contact filler according to any one of claims 1 to 7, characterized by being selected from the group consisting of the following.

9. The mixture of the thermally conductive filler is Al(OH) ３ and Al ２ O ３ An injectable heat-contact filler according to any one of claims 1 to 8, characterized by having the following features.

10. The injectable thermal 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 injectable heat-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 injectable heat-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 88 to 93% by weight, and the proportion of ZnO in the mixture of the fillers is 15 to 25% by weight.

13. A mixture of 1 to 10% by weight of the silane-functionalized prepolymer, wherein the polyurethane-based silane-functionalized prepolymer accounts for up to 50% by weight. 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 80 to 95% by weight of ZnO and 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, An injectable heat-contact filler according to any one of claims 1 to 12, characterized by having the following features.

14. A mixture of 1 to 7% by weight of the silane-functionalized prepolymer, wherein the polyurethane-based silane-functionalized prepolymer accounts for up to 50% by weight. 3 to 8% 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 83 to 93% by weight of ZnO and 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, An injectable heat-contact filler according to any one of claims 1 to 13, characterized by having the following features.

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

16. Use of an injectable thermal contact filler according to any one of claims 1 to 15 in a large-area electronic component.

17. Use of an injectable thermal contact filler according to any one of claims 1 to 15 in a battery system having a complex battery structure.

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