JP5005538B2 - Nanomaterial-containing organic matrix for increasing bulk thermal conductivity - Google Patents

Description

  The present invention relates to the use of nanoparticles to increase the thermal conductivity of a polymer matrix.

  Many electrical components generate heat during operation. If such heat is not efficiently removed from the electrical components, heat will accumulate. As a result, malfunction or permanent damage of electrical components can occur. Thus, thermal management techniques are often used in electrical circuits and systems to promote heat removal during operation.

  In thermal management technology, heat is often radiated from a high temperature region of an electric system using a heat sink of a certain form. The heat sink is a structure made of a material having high thermal conductivity (for example, typically metal), and mechanically couples with an electrical component to promote heat removal. In a relatively simple form, the heat sink is made of a piece of metal (eg, aluminum or copper) in contact with the electrical circuit in operation. Heat from the electrical circuit flows into the heat sink through the mechanical interface between the units.

In a typical electrical component, the heat sink is placed in contact with the heat generating component and the machine by placing the heat sink plane in contact with the electrical component plane in operation and holding the heat sink in place with some form of adhesive or securing means. Combined. As will be appreciated, there are usually voids between these surfaces because the surface of the heat sink and the surface of the component are rarely completely flat or smooth. As is well known, the presence of voids between two opposing surfaces reduces the ability to transfer heat through the interface between those surfaces. Such voids reduce the effectiveness and value of the heat sink as a thermal management device. To address this problem, polymer compositions have been developed for placement between heat transfer surfaces to reduce the thermal resistance between them. The bulk thermal conductivity of current thermal conductive materials is largely limited by the low thermal conductivity of the polymer matrix (about 0.2 W / mK for thermal conductive materials or polymers typically found in TIMs). In one approximation ("Thermal Conductive Polymer Compositions," DM Bigg., Polymer Compositions, June 1986, Vol. 7, No. 3), the maximum bulk thermal conductivity achievable with an electrically insulating polymer composite is Only 20-30 times the base polymer matrix. This number hardly changes regardless of the type of filler when the thermal conductivity of the filler exceeds 100 times the thermal conductivity of the base polymer matrix. Therefore, the thermal conductivity of the polymer material is lower than that of the heat sink, and heat transfer from the heat generating component to the heat sink becomes inefficient. In addition, 1) micro- or nano-voids and 2) micron-sized fillers cannot enter the surface irregularities smaller than the filler particle size or due to interface defects due to filler-deficient layers due to filler settling The effective heat transfer performance is further reduced.
“Thermal Conductive Polymer Compositions,” D. M.M. Bigg. , Polymer Compositions, June 1986, Vol. 7, no. 3

  Thus, there is a need for improved compositions that efficiently transfer heat between a heat sink and a heat generating component.

  The thermally conductive composition according to the present invention comprises a blend of nanoparticles functionalized with one or more organofunctional groups in an organic matrix. In some embodiments, the thermally conductive composition also includes micron sized filler particles.

  Also disclosed herein is an electrical component comprising a heat generating component and a heat sink or heat spreader each in contact with a thermally conductive composition made by blending organofunctionalized nanoparticles with an organic matrix.

  The method of increasing heat transfer efficiency according to the present invention includes the step of inserting a heat conducting composition comprising an organofunctionalized nanoparticle blended with an organic matrix between a heat generating component and a heat sink or heat spreader.

  The present invention provides a thermally conductive composition comprising functionalized nanoparticles blended with an organic matrix. The nanoparticles may be covalently bonded to the matrix or may be dispersed throughout the matrix with non-covalent forces. The matrix containing the nanoparticles of the present invention has a higher thermal conductivity than the matrix without nanoparticles. Functionalized nanoparticles increase the bulk thermal conductivity of the matrix while retaining a viscosity that is easy to process and handle.

  A polymer composite according to an embodiment comprising a nanoparticle-containing organic matrix and a micron-sized filler, described below, can achieve a higher thermal conductivity than a similar blend comprising only a micron-sized filler and an organic matrix. This improves the maximum achievable bulk thermal conductivity. Furthermore, since the nanoparticles can enter the pores and irregularities on the surface that cannot be penetrated by the filler having a micron size, the influence of the interface resistance can be reduced.

  Increased thermal conductivity in the polymer matrix is also advantageous in reducing interfacial resistance in cases where filler settling occurs and a “skin layer” (a layer containing little or no microfiller) appears. is there. If the skin layer has a higher thermal conductivity than otherwise achievable, the reduction in heat transfer will not be as severe. Another advantage of the nanoparticle formulation is that these particulates reduce or reduce the settling rate of micron sized fillers and reduce the probability of a filler-deficient layer in the thermally conductive material.

Any nanoparticle that can be functionalized and has a higher thermal conductivity than the organic matrix can be used in the preparation of the composition. Suitable nanoparticles include, but are not limited to, colloidal silica, caged silsesquioxane (“POSS”), nano-sized metal oxides (eg, alumina, titania, zirconia), nano-sized metal nitrides ( For example, boron nitride, aluminum nitride) and nano metal particles (for example, silver, gold or copper nanoparticles). In particularly useful embodiments, the nanoparticles are organofunctionalized POSS material or colloidal silica. Colloidal silica exists as a dispersion of submicron sized silica (SiO ₂ ) particles in aqueous or other solvents. Colloidal silica contains up to about 85% by weight silicon dioxide (SiO ₂ ), typically up to about 80% by weight silicon dioxide. The particle size of colloidal silica is typically about 1 nm to about 250 nm, and more typically about 5 to about 150 nm.

  The nanoparticles are functionalized to improve compatibility with the organic matrix. Thus, the exact chemical nature of the functional group added to the nanoparticle depends on a variety of factors, including the chemical nature of the particular nanoparticle involved and the chemical composition of the matrix. The functional group may be reactive, non-reactive, or a combination thereof. The reactive functional group is capable of reacting with either the organic matrix in which the nanoparticles are dispersed or the mating surface on which the final composition is provided. By chemical reaction, the nanoparticles bind to the organic matrix or the mating surface via covalent bonds. Suitable functionalizing agents include alkyl, alkenyl, alkynyl, silyl, siloxyl, acrylate, methacrylate, epoxide, aryl, hydride, amino, hydroxyl, and other organoalkoxysilanes, organochlorosilanes, organoacetate silanes, and organosilazanes having other functional groups. Is mentioned. Reaction schemes for adding functional groups to nanoparticles belong to the common general knowledge of those skilled in the art. Conveniently, the functionalized nanoparticles can be produced as a dispersion in a compatible solvent that facilitates mixing with the organic matrix. A particularly useful dispersion has a solid content of 20 to 50%, but any solid content can be used as long as the dispersion can be poured or fluidized.

  In particularly useful embodiments, the functionalized nanoparticles are colloidal silica functionalized with an organofunctionalized POSS material or an organoalkoxysilane.

  Organoalkoxysilanes used for functionalization of colloidal silica are included in the following formula.

(R ¹ ) _a Si (OR ² ) _4-a
In the formula, each R ¹ is independently a C _1-18 monovalent hydrocarbon group or a C _6-14 aryl group, and the C _1-18 monovalent hydrocarbon group is appropriately alkyl acrylate, alkyl methacrylate, epoxide, vinyl, allyl. May be further functionalized with styrenic, silyl or siloxyl groups, each R ² is independently a C _1-18 monovalent hydrocarbon group or hydrogen group, and “a” is an integer from 1 to 3. . Preferably, the organoalkoxysilane belonging to the technical scope of the present invention is 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, phenyltrimethoxysilane, methacryloxypropyltrimethyl. Methoxysilane (MAPTMS), 1-hexenyltriethoxysilane, n-octyltriethoxysilane, n-dodecyltriethoxysilane and 2- (3-vinyl-tetramethyldisiloxyl) -ethyltrimethoxysilane. Combinations of multiple functional groups are also possible. Typically, the organoalkoxysilane is present from about 2 to about 60% by weight, based on the weight of silicon dioxide contained in the colloidal silica. The resulting organofunctionalized colloidal silica may be treated with an acid or base to neutralize the pH. Acids or bases and other catalysts that promote the condensation of silanol and alkoxysilane groups can also be used to facilitate the functionalization process. Such catalysts include organotitanium and organotin compounds such as tetrabutyl titanate, titanium isopropoxybis (acetylacetonato), dibutyltin dilaurate, dibutyltin diacetate, or combinations thereof.

  The functionalization of the colloidal silica can be carried out by adding the organoalkoxysilane functionalizing agent in the above-mentioned weight ratio to a commercially available colloidal silica aqueous dispersion to which an aliphatic alcohol has been added. A composition comprising a functionalized colloidal silica and an organoalkoxysilane functionalizing agent in the resulting aliphatic alcohol is defined herein as a pre-dispersion. Suitable aliphatic alcohols include, but are not limited to, isopropanol, t-butanol, 2-butanol, 1-methoxy-2-propanol, and combinations thereof. The amount of aliphatic alcohol is typically about 1 to about 25 times the amount of silicon dioxide present in the aqueous colloidal silica predispersion. In some cases, a stabilizer such as 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (ie, 4-hydroxy TEMPO) may be added to the pre-dispersion. In some cases, a small amount of acid or base may be added to adjust the pH of the transparent predispersion.

  The resulting pre-dispersion is typically heated to about 50 to about 140 ° C. for about 1 to about 5 hours to promote condensation of the alkoxysilane with the OH groups on the surface of the colloidal silica to effect functionalization of the colloidal silica. Achieve.

  The functionalized nanoparticles are mixed with an organic matrix to form the composition of the present invention. The organic matrix can be any polymeric material. Suitable organic matrices include, but are not limited to, polydimethylsiloxane resins, epoxy resins, acrylate resins, other organofunctionalized polysiloxane resins, polyimide resins, fluorocarbon resins, benzocyclobutene resins, fluorinated polyallyl ethers, polyamides Resins, polyimide amide resins, phenolic resole resins, aromatic polyester resins, polyphenylene ether (PPE) resins, bismaleimide triazine resins, fluororesins and other polymer systems known to those skilled in the art. (For conventional polymers, see "Polymer Handbook", Branduf, J, Immergut, E.H, Gulke, Eric A, Wiley Interscience Publication, New York, 4th ed. (1999), M (See Oxford University Press, New York (1999).) Preferred curable thermosetting matrices include radical polymerization, atom transfer, radical polymerization ring-opening polymerization, ring-opening metathesis polymerization, anionic polymerization, cationic polymerization, and other acrylate resins that can form a crosslinked network structure by methods known to those skilled in the art, Epoxy resins, polydimethylsiloxane resins and other organofunctionalized polysiloxane resins. Suitable curable silicone resins include, for example, “Chemistry and Technology of Silicone”, Noll, W .; , Academic Press 1968, addition curable type and condensation curable type matrix. If the polymer matrix is not a curable polymer, the resulting thermally conductive composition can be formulated as a gel, grease or phase change material that can hold the parts together during manufacture and transfer heat during device operation. In particularly useful embodiments, the organic matrix is functionalized to improve compatibility with the functionalized nanoparticles.

  In order to facilitate mixing of the functionalized nanoparticles and the organic matrix, one or more solvents may be added to the composition as appropriate. Suitable aliphatic solvents include, but are not limited to, isopropanol, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, toluene, xylene, n-methylpyrrolidone, dichlorobenzene, and combinations thereof. .

  The mixing method of the functionalized nanoparticles and the organic matrix is not particularly important. When the nanoparticles are blended with the preliminary dispersion, an organic matrix and an appropriate solvent may be added to the preliminary dispersion.

  The composition may be treated with an acid or base or ion exchange resin to remove acidic or basic impurities. Preferably, the composition is subjected to a vacuum of about 0.5 to about 250 torr and a temperature of about 20 to about 140 ° C. to substantially reduce low boiling components such as solvent, residual water, combinations thereof. Can be removed. The result is a dispersion of functionalized nanoparticles in an organic matrix, referred to herein as the final dispersion. Substantial removal of low boiling components is defined herein as removal of about 90% or more of the total amount of low boiling components.

  Optionally, the pre-dispersion or final dispersion of functionalized colloidal silica may be further functionalized. After at least partially removing the low boiling components, a suitable sequestering agent that reacts with the residual hydroxyl functionality of the functionalized colloidal silica is about 0.05 to about the amount of silicon dioxide present in the pre-dispersion or final dispersion. Add in 10 times the amount. Partial removal of low boiling components herein refers to removal of about 10% or more of the total amount of low boiling components, preferably about 50% or more of the total amount of low boiling components. Capped functionalized colloidal silica is defined as having 10% or more, preferably 20% or more, more preferably 35% or more of the free hydroxyl groups present in the overall composition functionalized by reaction with a capping agent. . Effective blockage of the functionalized colloidal silica can improve the room temperature stability of the final dispersion in some cases.

  Preferred sequestering agents include hydroxyl reactive materials such as silylating agents. Examples of silylating agents include, but are not limited to, hexamethyldisilazane (HMDZ), tetramethyldisilazane, divinyltetramethyldisilazane, diphenyltetramethyldisilazane, N- (trimethylsilyl) diethylamine, 1- (trimethylsilyl) Examples include imidazole, trimethylchlorosilane, pentamethylchlorodisiloxane, pentamethyldisiloxane, and combinations thereof. The final dispersion is then heated at about 20 to about 140 ° C. for about 0.5 to about 48 hours. The resulting mixture is filtered. When the pre-dispersion is reacted with a sequestering agent, one or more organic matrix compositions are added to form the final dispersion. The mixture of functionalized colloidal silica in the organic material is concentrated at a pressure of about 0.5 to about 250 torr to form a final concentrated dispersion. This process substantially removes low boiling components such as solvents, residual water, sequestering and hydroxyl side products, excess sequestering agents and combinations thereof.

  Optionally, the entire final dispersion composition may be blended with a micron sized filler. The addition of micron sized fillers can substantially increase the thermal conductivity of the composition. Thus, the addition of microfillers greatly amplifies the effect of functionalized nanoparticles on the thermal conductivity of the polymer matrix. For example, when the thermal conductivity of the polymer matrix is 0.2 W / m-K, the thermal conductivity can be increased to 2.0 W / m-K by adding 80 to 90 wt% of an appropriate micro filler. However, the addition of functionalized nanoparticles according to the present invention can further increase the initial thermal conductivity of the polymer matrix to 0.3 W / m-K or more, and the addition of the same amount of micron-sized filler as described above can increase the thermal conductivity. The conductivity increases to about 3 W / m-K, an increase of 50% compared to the composition without nanoparticles. When the thermal conductivity is increased to 3 W / m-K by adding only microparticles, a very viscous composition is obtained, which is not easy to process and is necessary for the manufacture of electronic devices, especially flip / chip devices. Does not flow as much as possible. On the other hand, the use of nanoparticles according to the present invention increases the thermal conductivity while maintaining a sufficiently low viscosity that can be easily processed.

  The filler is a heat conductive material having a micron particle size, and may be reinforcing or non-reinforcing. Examples of the filler include fumed silica, fused silica, quartz fine powder, amorphous silica, carbon black, graphite, diamond, metal (for example, silver, gold, aluminum, copper), silicon carbide, aluminum hydrate, metal Examples include nitrides (eg, boron nitride, aluminum nitride), metal oxides (eg, aluminum oxide, zinc oxide, titanium dioxide, or iron oxide), and combinations thereof. When present, the filler is typically present in an amount of about 10 to about 95 weight percent, based on the weight of the entire final composition. More typically, the filler is present in an amount of about 20 to about 90% by weight, based on the total weight of the final dispersion composition.

  The presence of nanoparticles in the composition also improves the stability of the composition in the presence of microfillers. Nanoparticles have been found to suppress sedimentation of microparticles to the bottom of a container containing the composition as compared to a composition containing the same amount of microfiller but no nanoparticles.

  A curing catalyst may be added to the final dispersion to promote curing of the final composition. Typically, the catalyst is present in an amount from about 10 ppm to about 10% by weight of the total curable composition. Examples of the cationic curing catalyst include, but are not limited to, bisaryliodonium salts (for example, bis (dodecylphenyl) iodonium hexafluoroantimonate, hexafluoroantimonic acid (octyloxyphenylphenyl) iodonium, tetrakis (pentafluorophenyl) Onium catalysts such as bisaryliodonium borate), triarylsulfonium salts, and combinations thereof. Examples of the radical curing catalyst include, but are not limited to, various peroxides (for example, tert-butylperoxybenzoate), azo compounds (for example, 2-2′-azobis-isobutylnitrile), and nitroxides (for example, 4-hydroxy TEMPO). It is done. For addition curable silicone resins, preferred catalysts are various Group 8-10 transition metal (eg, ruthenium, rhodium, platinum) complexes. For condensation curable silicones, the preferred catalyst is an organotin or organotitanium complex. Details of the structure of these catalysts are known to those skilled in the art.

  For the cationic curable matrix, an effective amount of a radical generating compound such as aromatic pinacol, benzoin alkyl ether, organic peroxide and a combination thereof may be added as an optional component. The radical generating compound accelerates the decomposition of the onium salt at a low temperature.

  In the epoxy resin, a curing agent such as a carboxylic acid anhydride-based curing agent and a hydroxyl group-containing organic compound may be added as an optional component together with the curing catalyst. In this case, the curing catalyst is not particularly limited and can be selected from amines, alkyl-substituted imidazoles, imidazolium salts, phosphines, metal salts, triphenylphosphine, alkyl-imidazoles and aluminum acetylacetonates and combinations thereof. About an epoxy resin, you may mix | blend hardener like polyfunctional amine as a crosslinking agent suitably. Representative amines include, but are not limited to, ethylenediamine, propylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, and other compounds having two or more amino groups.

  For epoxy resins, representative anhydride curing agents include methylhexahydrophthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, bicyclo [2.2.1] hept-5-ene-2,3- Dicarboxylic anhydride, methylbicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic anhydride, phthalic anhydride, pyromellitic dianhydride, hexahydrophthalic anhydride, dodecenyl succinic anhydride, Examples thereof include dichloromaleic anhydride, chlorendic anhydride, and tetrachlorophthalic anhydride. Combinations comprising two or more anhydride hardeners can also be used. A specific example is “Chemistry and Technology of the Epoxy Resins”. Ellis (Ed.) Chapman Hall, New York, 1993 and “Epoxy Resins Chemistry and Technology”, edited by C.I. A. May, Marcel Dekker, New York, 2nd edition, 1988.

  In addition curable silicone resins, polyfunctional Si—H containing silicone fluids such that the Si—H / vinyl molar ratio in the final formulation is 0.5 to 5.0, preferably 0.9 to 2.0. A crosslinking agent such as

  In the addition-curable silicone resin, an inhibitor may be appropriately blended in order to achieve desired storage stability by changing the curing characteristics. Examples of the inhibitor include, but are not limited to, phosphine compounds, amine compounds, isocyanurates, alkynyl alcohols, maleic esters and other compounds known to those skilled in the art.

  Moreover, in order to reduce the viscosity of a composition, you may add a reactive organic diluent to the whole curable composition. Examples of reactive diluents include, but are not limited to, 3-ethyl-3-hydroxymethyl-oxetane, dodecyl glycidyl ether, 4-vinyl-1-cyclohexane diepoxide, di (β- (3,4-epoxycyclohexyl). ) Ethyl) -tetramethyldisiloxane, various dienes (eg 1,5-hexadiene), alkenes (eg n-octene), alkenes, styrenic compounds, acrylates or methacrylate-containing compounds (eg methacryloxypropyltrimethoxysilane) and These combinations are mentioned. Non-reactive diluents may be added to the composition to reduce the viscosity of the formulation. Examples of non-reactive diluents include, but are not limited to, low boiling aliphatic hydrocarbons (eg, octane), toluene, ethyl acetate, butyl acetate, 1-methoxypropyl acetate, ethylene glycol, dimethyl ether, and combinations thereof. Can be mentioned.

  Effective amounts of adhesion promoters such as trialkoxyorganosilanes may be used throughout the final dispersion, for example, γ-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, bis (trimethoxy And silylpropyl) fumarate. Effective amounts are typically from about 0.01 to about 2% by weight based on the total final dispersion.

  Optionally, a flame retardant can also be used throughout the final dispersion at about 0.5 to about 20 weight percent based on the total amount of the final dispersion. Examples of flame retardants include phosphoramide, triphenyl phosphate (TPP), resorcinol diphosphate (RDP), bisphenol-A-diphosphate (BPA-DP), organic phosphine oxide, halogenated epoxy resin (tetrabromobisphenol A), Examples include metal oxides, metal hydroxides, and combinations thereof.

  The final dispersion composition may be kneaded by hand or mixed with conventional mixing equipment such as a dough mixer, chain can mixer, planetary mixer, twin screw extruder, two or three roll mill. The blending of the dispersion components can be carried out by a batch method, a continuous method or a semi-continuous method by any means used by those skilled in the art.

  The curing process can be carried out by methods known to those skilled in the art. Curing can be performed by methods such as thermal curing, UV light curing, microwave curing, electron beam curing, and combinations thereof. Curing typically occurs at a temperature of about 20 to about 250 ° C, more typically about 20 to about 150 ° C. Curing typically occurs at a pressure of from about 1 atmosphere ("atm") to about 5 tons / square inch, more typically from about 1 atmosphere to about 100 pounds / square inch ("psi"). Curing typically occurs from about 30 seconds to about 5 hours, more typically from about 90 seconds to about 60 minutes. Optionally, the cured composition may be post-cured at a temperature of about 100 to about 150 ° C. for about 1 to about 4 hours.

  The addition of functionalized nanoparticles is used to increase the bulk thermal conductivity of the base polymer matrix and improves the thermal conductivity, especially when placed between two objects, such as between components of an electrical component. Moreover, the heat conductive composition of this invention reduces the interfacial thermal resistance which exists essentially on the surface of two components which the above heat | fever transfers. The heat conducting composition of the present invention can be used in electronic devices such as computers and semiconductors or any device that requires heat transfer between components. For example, as schematically shown in FIG. 1, if the heat conductive composition 2 of the present invention is interposed between the semiconductor chip 3 and the heat sink 1, the gap can be filled to promote heat transfer. The layer 2 of the heat conducting composition of the present invention can be as thin as 20-150 microns and still provide the desired effect. The application of the heat conductive composition of the present invention can be accomplished by methods known in the art. Conventional methods include screen printing, stencil printing, shilling distribution and pick and place equipment.

  In another embodiment, the composition of the present invention may be formed into a sheet and cut into a desired shape. In this embodiment, the composition of the present invention is preferably used as a thermally conductive pad and placed between electronic components.

  Although the preferred embodiments of the present invention have been described above, other embodiments belonging to the technical scope of the present invention described in the claims will be obvious to those skilled in the art.

Reference example 1
4.95 g of the dispersion composition consisted of 31 wt% (wt% based on unfunctionalized colloidal SiO ₂ ) methacryloxypropyltrimethoxysilane (“MAPPTMS”) functionalized colloidal SiO ₂ (20 nm) and acryloxy-terminated poly. It consisted of dimethylsiloxane (Gelest DMSU22, MW about 1000-1200). Further, 2 g of MAPTMS, 0.13 g of iodonium salt (UV 9380c manufactured by GE Silicones) and 45.6 g of alumina (AS10 manufactured by Showa Denko KK) were blended into the dispersion composition. The amount of alumina added was 86.5 wt% of the total formulation. The dispersion composition was cured at 120 ° C. When the thermal conductivity of the dispersion composition was measured, it was 2.6 W / mK ± 0.05 at room temperature and 2.55 W / mK at 100 ° C. As a comparison, the thermal conductivity of acrylate alone is about 1.4 to 1.9 w / m-K at 100 ° C. when filled with 86.5 wt% alumina (average particle size = 38 microns). See Table 1.

Reference example 2
1.82 g octakis (dimethylsiloxy-T8-silsesquioxane) (T ₈ ^OSiMe2H , Gelest), 0.73 g 1,5-hexamethyl-trisiloxane ( ^MH DM ^H GE Silicones), 1.53 g 1,3-divinyltetramethyldisiloxane (manufactured by GE Silicones), 1.04 g of vinyl-terminated polydimethylsiloxane (manufactured by Gelest, MW9400) DMSV22, a suitable catalyst and 20 g of alumina (AS-manufactured by Showa Denko KK) 40 and a dispersion composition of Sumitomo Chemical Co., Ltd. AA04). The amount of alumina added was about 80 wt% of the total formulation. The dispersion composition was cured at 80 ° C. When the thermal conductivity of the dispersion composition was measured, it was 1.99 W / mK ± 0.15 at room temperature and 1.70 W / mK ± 0.10 at 100 ° C. For comparison, the thermal conductivity of polydimethylsiloxane (“PDMS”) is about 1.00 W / m-K when filled with 80 wt% alumina (average particle size is 10 μm for AS40 and 0.4 μm for AA04). See Table 1.

Reference example 3
7 g GE Silicones FCS100 (40 wt% MAPTMS functionalized colloidal SiO ₂ in 1,6-hexanediol diacrylate), 0.14 g iodonium salt (GE Silicones UV9380c) and 43 g alumina (Showa) A dispersion composition containing AS50 manufactured by Electric Works Co., Ltd. and AA04 manufactured by Sumitomo Chemical Co., Ltd.) was blended. The amount of alumina added was 86 wt% of the total formulation. When the thermal conductivity of the dispersion was measured, it was 3.35 W / m-K ± 0.20 W / m-K at room temperature and 3.25 W / m-K ± 0.15 at 100 ° C. For comparison, the thermal conductivity of acrylate is about 1.4 to 1.9 w at 100 ° C. when 86.5 wt% alumina (average particle size is 10 μm for AS50, 0.4 μm for Sumitomo Chemical Co., Ltd.). / M-K. See Table 1.

Reference example 4
The final dispersion consisted of 56 wt% phenyltrimethoxysilane functionalized colloidal silica (based on SiO ₂ content and functional groups), 1 wt% iodonium salt (GE) as catalyst in alicyclic epoxy resin (UVR6105 from Dow). It consisted of UV9392c manufactured by Silicones) and 0.5 wt% benzoylpinacol (manufactured by Aldrich). The dispersion was cured at 156 ° C. for 5 minutes and measured to have a thermal conductivity of 0.37 W / m-K at 25 ° C. The thermal conductivity of a typical epoxy without nanoparticles is 0.2-0.25 W / m-K at 25 ° C.

Example 1
The final dispersion is composed of 22 wt% colloidal silica functionalized with phenyltrimethoxysilane and end-capped with hexamethyldisilazine (HMDZ) in vinyl-terminated polydimethyl-co-diphenyl-siloxane (Gelest PDV1625). It was. The wt% of colloidal silica and condensed functional groups is about 27%. 5.33 g of the final dispersion was added to 0.04 g of a platinum catalyst package ([Pt] = 7.5 ppm in the final formulation) and 0.14 g of polydimethyl-co-methylhydrido-siloxane (GE Silicones 88466). Mixed with. The final formulation was a flowable material. The composition was cured at 150 ° C. for 1 hour to obtain a material having a bulk thermal conductivity of 0.17 W / m-K.

Reference Example 5
10.06 g vinyl-terminated polydimethyl-co-diphenyl-siloxane (PDV1625 from Gelest), 0.38 g polydimethyl-co-methylhydrido-siloxane (88466 from GE Silicones), 1.10 g phenyltrimethoxysilane And a 0.10 g catalyst package (target [Pt] = 7.5 ppm in final formulation) was prepared. 2.76 g of this stock solution was mixed with 0.44 g of fused silica (manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size = 5 microns) and 0.35 g of double-treated fumed silica (88318, manufactured by GE Silicones). did. This mixture was a non-flowable high viscosity paste.

The composition was cured at 150 ° C. for 1 hour. The bulk thermal conductivity was 0.17 W / m-K at 25 ° C. as in Example 1 .

Example 7
An appropriate amount of the final dispersion described in Example 5 was manually formed into an X-shape from a syringe on an 8 × 8 mm aluminum coupon. A second aluminum coupon was placed thereon, and the resulting sandwich structure was placed in an oven at 150 ° C. for 1 hour to complete the curing. The TIM layer has a bonding surface (bond line) thickness of 16.8 microns. The effective thermal conductivity of the TIM layer is 0.18 W / m-K at 25 ° C. The total thermal resistance through the TIM layer was 94 mm ² -K / W.

A similar three-layer sandwich structure was made with the formulation described in Reference Example 5 . The joint surface thickness was 23 microns, and the effective thermal conductivity of the TIM layer was 0.13 W / m-K at 25 ° C. The total thermal resistance through the TIM layer was 173 mm ² -K / W.

  Although the preferred embodiments of the present invention have been described above, other embodiments belonging to the technical scope of the present invention described in the claims will be obvious to those skilled in the art.

FIG. 1 is a schematic view of an electrical component according to the present invention.

Claims (7)

A thermally conductive composition comprising a blend of organofunctionalized nanoparticles and a curable polymer matrix comprising:
The organo-functionalized nanoparticles are organo-functionalized colloidal silica, organo-functionalized colloidal silica is colloidal silica mosquito the formula
(R ¹ ) _a Si (OR ² ) _4-a
(In the above formula, each R ¹ is independently a C _1-18 monovalent hydrocarbon group, and the monovalent hydrocarbon group is an alkyl acrylate, alkyl methacrylate, epoxide, vinyl, allyl, styrenic, silyl or siloxyl group. And each R ² is independently a C _1-18 monovalent hydrocarbon group or a hydrogen group, and a is an integer of 1 to ^3. )
Functionalized with an organoalkoxysilane represented in state, and are not further functionalized with a silylating agent, the silylating agent, hexamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, diphenyl tetramethyl silazane, N- (trimethylsilyl) diethylamine, 1- (trimethylsilyl) imidazole, trimethylchlorosilane, pentamethyl chloro disiloxane, Ru least 1 Tsudea selected from pentamethyl disiloxane, and combinations thereof, thermally conductive composition. The curable polymer matrix is an acrylate resin;
The heat conducting composition according to claim ^1, wherein R ¹ is a C _1-18 monovalent hydrocarbon group functionalized with alkyl acrylate or alkyl methacrylate.   Furthermore, the heat conductive composition of Claim 1 or Claim 2 containing the filler of a micron particle size. Stage heat generating component (3) is placed in contact with the thermally conductive composition comprising a blend of a curable polymer matrix and organo-functionalized nanoparticles (2), and the heat sink (1) a thermally conductive composition ( 2) a method for increasing heat transfer, comprising the step of placing in contact with
The organo-functionalized nanoparticles are organo-functionalized colloidal silica, organo-functionalized colloidal silica is colloidal silica mosquito the formula
(R ¹ ) _a Si (OR ² ) _4-a
(In the above formula, each R ¹ is independently a C _1-18 monovalent hydrocarbon group, and the monovalent hydrocarbon group is an alkyl acrylate, alkyl methacrylate, epoxide, vinyl, allyl, styrenic, silyl or siloxyl group. And each R ² is independently a C _1-18 monovalent hydrocarbon group or a hydrogen group, and a is an integer of 1 to ^3. )
Functionalized with an organoalkoxysilane represented in state, and are not further functionalized with a silylating agent, the silylating agent, hexamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, diphenyl tetramethyl silazane, N- (trimethylsilyl) diethylamine, 1- (trimethylsilyl) imidazole, trimethylchlorosilane, pentamethyl chloro disiloxane, Ru least 1 Tsudea selected from pentamethyl disiloxane, and combinations thereof, methods. Exothermic part (3),
Heat sink (1), and heat conductive composition (2) interposed between heat generating portion (3) and heat sink (1)
An electronic component comprising the thermally conductive composition (2) comprises a blend of a curable polymer matrix and organo-functionalized nanoparticles,
The organo-functionalized nanoparticles are organo-functionalized colloidal silica, organo-functionalized colloidal silica is colloidal silica mosquito the formula
(R ¹ ) _a Si (OR ² ) _4-a
(In the above formula, each R ¹ is independently a C _1-18 monovalent hydrocarbon group, and the monovalent hydrocarbon group is an alkyl acrylate, alkyl methacrylate, epoxide, vinyl, allyl, styrenic, silyl or siloxyl group. And each R ² is independently a C _1-18 monovalent hydrocarbon group or a hydrogen group, and a is an integer of 1 to ^3. )
Functionalized with an organoalkoxysilane represented in state, and are not further functionalized with a silylating agent, the silylating agent, hexamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, diphenyl tetramethyl silazane, N- (trimethylsilyl) diethylamine, 1- (trimethylsilyl) imidazole, trimethylchlorosilane, pentamethyl chloro disiloxane, Ru least 1 Tsudea selected from pentamethyl disiloxane, and combinations thereof, the electronic component.   The electronic component according to claim 5, wherein the heat conductive composition (2) comprises a pre-formed pad. Micron particle size of the filler to a method of delaying the phase separation of the filled polymer composition comprises a blending organo-functionalized nanoparticles in the curable polymer composition,
The organo-functionalized nanoparticles are organo-functionalized colloidal silica, organo-functionalized colloidal silica is colloidal silica mosquito the formula
(R ¹ ) _a Si (OR ² ) _4-a
(In the above formula, each R ¹ is independently a C _1-18 monovalent hydrocarbon group, and the monovalent hydrocarbon group is an alkyl acrylate, alkyl methacrylate, epoxide, vinyl, allyl, styrenic, silyl or siloxyl group. And each R ² is independently a C _1-18 monovalent hydrocarbon group or a hydrogen group, and a is an integer of 1 to ^3. )
Functionalized with an organoalkoxysilane represented in state, and are not further functionalized with a silylating agent, the silylating agent, hexamethyldisilazane, tetramethyldisilazane, divinyltetramethyldisilazane, diphenyl tetramethyl silazane, N- (trimethylsilyl) diethylamine, 1- (trimethylsilyl) imidazole, trimethylchlorosilane, pentamethyl chloro disiloxane, Ru least 1 Tsudea selected from pentamethyl disiloxane, and combinations thereof, methods.