Thermal grease composition

Abstract

The present invention relates to a composition comprising one or more filler particles and a first treating agent of Formula 1: [Chemical Formula 1] JPEG2026509476000016.jpg35170 a second treating agent of Formula 2: [Chemical Formula 2] JPEG2026509476000017.jpg35170 (wherein R, R 1 , R 2 , Y, x, and n are as defined herein) ​

Description

[Technical Field]

[0001] The present invention relates to a non-curing thermal grease composition comprising an ester-functionalized trialkoxysilane. [Background technology]

[0002] Non-curing thermal greases are widely used as thermal interface materials for transferring heat from heat-generating electronic components to heat sinks. Useful thermal greases are characterized by high bulk thermal conductivity, low thermal resistance, thin bond line thickness, and good fluidity and reworkability. More than 90% by weight of the components constituting the thermal grease are combinations of thermally conductive fillers such as zinc oxide, alumina, aluminum, boron nitride, and aluminum nitride dispersed in a silicone-based fluid. As the power and power density of electronic components increase rapidly, greater heat generation occurs, requiring a higher thermal conductivity for the thermal grease.

[0003] Thermal conductivity can be increased by increasing the amount of thermally conductive filler used in the preparation of thermal grease. Unfortunately, however, higher filler amounts increase the viscosity of the thermal grease, which degrades important properties such as printability and thermal stability. To address this problem, U.S. Patent Application Publication 2008 / 0213578(A1) (Endo) discloses a thermal grease composition comprising, in particular, a trialkylsilyl-trialkoxysilyl-terminated polysiloxane (component B, paragraph

[0034] ) and an alkoxysilane (component C, paragraph

[0035] ), wherein the inclusion of component C provides lower viscosity and, consequently, improved thermal stability of the thermal grease compared to greases that do not contain this component.

[0004] Furthermore, achieving even better thermal stability remains a need, and therefore, finding a thermal grease that can achieve higher thermal conductivity without compromising thermal stability is advantageous in the field of non-curing thermal grease technology. [Overview of the project]

[0005] The present invention relates to a composition comprising, based on the weight of the composition, a) 80 to 95 weight percent of one or more filler particles selected from the group consisting of aluminum, alumina, silicon, silicon dioxide, magnesium oxide, aluminum nitride, graphite, silicon carbide, and zinc oxide, and b) 0.2 to 15 weight percent of a first treatment agent of formula 1:

[0006] [ka] (wherein R and R 1′ (Each of the elements is independently a C1-C6 alkyl group, Y is O or CH2-CH2, and x is 20-200), c) 0.05-2 weight percent of ester-functionalized trialkoxysilane of formula 2:

[0007] [ka] (In the formula, R 2 C1~C 16 -Alkyl or C2~C 16 -It is an alkenyl, and each R 1 (where n is independently a C1-C6 alkyl group, and n is 1 or 2), d) Up to 8 weight percent boron nitride platelet particles, By providing a composition containing [the specified element], the need in the field of non-curing thermal greases is addressed.

[0008] The composition of the present invention is useful as a non-curing thermal grease. [Modes for carrying out the invention]

[0009] The present invention relates to a composition comprising, based on the weight of the composition, a) 80 to 95 weight percent of one or more filler particles selected from the group consisting of aluminum, alumina, silicon, silicon dioxide, magnesium oxide, aluminum nitride, silicon carbide, graphite, and zinc oxide, and b) 0.2 to 15 weight percent of a first treating agent of formula 1:

[0010] [Chemical formula] (wherein R and R 1′ are each independently C1-C6-alkyl, Y is O or CH2-CH2, and x is 20 to 200), and c) 0.05 to 2 weight percent of an ester-functionalized trialkoxysilane of formula 2:

[0011] [Chemical formula] (wherein R 2 is C1-C 16 -alkyl or C2-C 16 -alkenyl, each R 1 is independently C1-C6-alkyl, and n is 1 or 2), and d) up to 8 weight percent of boron nitride platelet particles, and A composition comprising

[0012] The composition preferably contains aluminum and zinc oxide filler particles in a total concentration ranging from 85 or 90 weight percent to 95 weight percent, based on the weight of the composition. The concentration of aluminum particles is preferably in the range from 65, or 68, or 70 weight percent to 80, or 78, or 75 weight percent of the composition. The aluminum particles are advantageously a) smaller particles having a D 50 volume average particle size in the range from 0.5 μm or 1 μm to 5 μm or 3 μm, and b) D 50 in the range from 7 μm to 20 μm, or 15 μm, or 12 μmThis is a bimodal distribution of larger particles with a volume-average particle size.

[0013] The concentration of ZnO particles is preferably in the range of 10 or 15 weight percent to 25 or 20 weight percent based on the weight of the composition. The ZnO particles are preferably in the range of 50 nm or 80 nm to 500 nm or 200 nm or 150 nm. 50 It has a volume-average particle size. D of aluminum, zinc oxide, and alumina particles 50 and D 99 The volume-average particle size is D, measured using the laser refractive index method. 50 This refers to the volume-average particle size.

[0014] The concentration of the first treatment agent of Formula 1 ranges from 0.2, 1, 3, or 5 weight percent to 15 or 10 weight percent based on the weight of the composition. Y is preferably O, and R and R 1 Each is preferably methyl, and x is from 20 or 50 to 200 or 250.

[0015] The concentration of the ester-functionalized trialkoxysilane ranges from 0.05 or 0.1 weight percent to 2 or 1 or 0.5 weight percent based on the weight of the composition. R is C1~C 16 -Alkyl, or C1-C 10 -alkyl, or C1-C6-alkyl, or C2-C 16 - Alkenyl, or C2~C 10 - is an alkenyl, where R is preferably methyl, and each R 1 The elements are independently C1-C6 alkyl, preferably methyl, and n is preferably 1 or 2.

[0016] The ester-functionalized trialkoxysilane of formula 2 can be prepared, for example, by the condensation of a carboxylic acid salt with a trialkoxysilyl alcohol, as described in International Publication No. 2011 / 101278(A1). The compound of formula 1 is obtained by a base-catalyzed reaction of a carboxylic acid salt with a chloroalkyltrialkoxysilane:

[0017] [ka] Alternatively, it can be prepared by hydrosilylation of allyl esters and trichlorosilanes followed by alkanol degradation.

[0018] [ka]

[0019] The composition optionally includes boron nitride platelet particles that increase thermal conductivity at the expense of viscosity. The platelet particles have a thickness preferably in the range of 750 nm to 5 μm when measured by scanning electron microscopy (SEM), and preferably in the range of 3 μm to 40 μm when measured by dynamic light scattering. 50 The boron nitride platelet particles have a particle size. The diameter-thickness aspect ratio of the boron nitride platelet particles is preferably in the range of 2:1, or 3:1, or 4:1 to 50:1, or 30:1, or 20:1, or 10:1. The boron nitride platelet particles have a hexagonal crystal structure. During aggregation, the boron nitride platelet particles align along substantially the same direction as the substrate after the platelet particles are applied between the substrates. Therefore, the D 50 Particle size does not affect the final bond line thickness. Examples of commercially available boron nitride platelet particles include CarboTherm PCTP30 boron nitride from St. Gobain and PolarTherm PT110 from Momentive Performance Materials. The concentration of boron nitride platelet particles ranges from 0, 0.5, 1, or 2 weight percent to 8, 6, 5, or 4 weight percent based on the weight of the composition.

[0020] The present invention provides a non-curing grease that can achieve high thermal conductivity with a distributable and processable viscosity. [Examples]

[0021] In the following examples, pbw refers to parts by weight. All mixing was performed using a Flacktek Speedmixer at 1500 rpm unless otherwise specified.

[0022] General procedure for preparing thermally conductive materials Formula 1's first filler treatment agent (TA1, 7.09pbw, each R and R 1 =CH3, R=O, and x=110 (prepared as described in U.S. Patent Application Publication No. 2006 / 0100336), a second filler treatment agent (TA-2~TA-6, 0.2 pbw), and Zoco 102 ZnO particles (ZnO, 17.38 pbw, 0.12 μm) were added to a MAX 100 cup and mixed for 15 seconds. Then, the first aluminum particles (Al-1, 24.12 pbw, 2.0 μm, equivalent to TCP-2 Al powder) were added to the mixer and the contents were mixed for 15 seconds. Then, TCP-9 Al powder (Al-2, 48.24 pbw, 9.9 μm) was added to the mixer and mixing continued for 40 seconds. The mixture was then mixed by hand using a spatula and then further mixed in the mixer for 40 seconds. Then, boron nitride (BN, 3 pbw) was added to the mixer and mixing continued for 15 seconds. The prepared composition was transferred to an aluminum pan and heated under vacuum (23 Torre) at 150°C for 1 hour.

[0023] Table 1 summarizes the materials and quantities used to prepare the examples and comparative examples. TA-2, TA-3, TA-4, TA-5, and TA-6 have the following structures.

[0024] [ka]

[0025] [Table 1]

[0026] Viscosity measurement The complex viscosity (Pa·s) at the dilatant point was measured using the TA Instruments ARES-G2 apparatus model with a 25 mm parallel plate (serrated steel) according to ASTM D4440-15 (Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology). Test conditions were based on strain sweeps performed at 25°C with a 2.0 mm gap. Care was taken to prevent air from being introduced into the sample during loading. Excess material was scraped off the edge of the fixture with the flat edge of a spatula. Measurements were performed by sweeping strain amplitudes from 0.01 to 300% at 20 sampling points per decade using the standard procedure with an oscillation frequency of 10 rad / s. The dilatant point was defined as the strain at which the complex viscosity began to increase.

[0027] Thermal conductivity measurement Thermal conductivity was measured using a Hot Disk Instrument TPS 2500 S and a C5501 sensor according to ISO 22007-2:2015 (Test Method for Determining Thermal Conductivity). Each sample was placed in two cups, and a flat sensor was held between the cups. Analysis conditions: fine-tuned analysis, temperature drift compensation and time correction, and calculations selected between 50 and 150 points.

[0028] Table 2 shows the viscosity and thermal conductivity results for the samples. Viscosity refers to the viscosity at the dilatant point.

[0029] [Table 2]

[0030] The results show a significant improvement in viscosity for Comparative Example 3 of the present invention.

[0031] Sample stability measurement Thickness measurement of the sample before aging The sample (1g) was distributed onto a substrate (0.65mm × 75mm × 125mm) pre-treated with Q-Panel-AL-35 and chromate. An aluminum spacer (1mm thick) was placed on one side of the distributed sample, and a glass slide (50mm × 75mm) was placed on top of the spacer and sample. The spacer was removed, and a texture analyzer probe (13mm diameter) was directed towards the glass slide at a speed of 0.5mm / s until the probe contacted the slide. At the point of contact, 5 kg of force was applied to the slide for 30 seconds. The thickness of the sample (thickness) was then measured. o The fluidity before aging was measured and subtracted from the thickness of the substrate and slide.

[0032] Thickness measurement of the sample after aging The sample was distributed, and the aluminum spacer (1 mm thick) and slide glass were arranged as described above. The stability of the sample was determined as follows: The assembly was heated to 125°C for 21 days. The spacer was removed, and the probe was directed towards the slide glass at a speed of 0.5 mm / second until it made contact with the slide glass. At the point of contact, 5 kg of force was applied to the slide glass for 30 seconds. Then, the thickness of the sample (thickness) f The fluidity after aging was measured as described above.

[0033] Table 3 summarizes the initial thickness of the sample before aging and the thickness of the sample after aging. o This refers to the initial thickness of the sample, and thickness f This refers to the thickness of the sample after aging following the application of force.

[0034] [Table 3]

[0035] The thickness of the comparative example did not decrease substantially, indicating that the sample hardened. In contrast, all examples containing the esterifying agent of Formula 2 showed fluidity, which is an indicator of the relative stability of the sample.

Claims

1. A composition comprising, based on the weight of the composition, a) 80 to 95 weight percent of one or more filler particles selected from the group consisting of aluminum, alumina, silicon, silicon dioxide, magnesium oxide, aluminum nitride, silicon carbide, graphite, and zinc oxide, and b) 0.2 to 15 weight percent of a first treatment agent of formula 1: 【Chemistry 1】 (In the formula, R and R １′ Each of them is independent of C １ ~C ６ - It is an alkyl group, and Y is either O or CH ２ -CH ２ (where x is between 20 and 200), c) 0.05 to 2 weight percent of ester-functionalized trialkoxysilane of formula 2: 【Chemistry 2】 (wherein, R ２ is C １ ~ C １６ - alkyl or C ２ ~ C １６ - alkenyl, and each R １ is independently C １ ~ C ６ - alkyl, and n is 1 or 2), and d) Up to 8 weight percent boron nitride platelet particles, A composition containing the following:

2. The composition according to claim 1, wherein the filler particles are selected from the group consisting of aluminum, alumina, and zinc oxide.

3. a) aluminum and zinc oxide filler particles in a total concentration in the range of 85 to 95 weight percent based on the weight of the composition; and b) boron nitride platelet particles in a concentration in the range of 0.5 to 8 weight percent based on the weight of the composition.

4. Y is O, and each R and R １ The composition according to claim 3, wherein the methyl

5. The composition according to claim 2, wherein the concentration of the first treatment agent of formula 1 is in the range of 3 to 10 weight percent based on the weight of the composition, and the concentration of the ester-functionalized trialkoxysilane of formula 2 is in the range of 0.1 to 1 weight percent based on the weight of the composition.

6. The concentration of aluminum particles is in the range of 65 to 80 weight percent based on the weight of the composition, the concentration of zinc oxide particles is in the range of 10 to 25 weight percent based on the weight of the composition, and the aluminum particles are a) in the range of 0.5 μm to 5 μm. ５０ Smaller particles having a volume-average particle size and b) D in the range of 7 μm to 20 μm ５０ A bimodal distribution of larger particles having a volume-average particle size, wherein the zinc oxide particles are in the range of 50 nm to 200 nm. ５０ The composition according to claim 3, having a volume-average particle size.

7. The concentration of aluminum particles is in the range of 70 to 78 weight percent based on the weight of the composition, the concentration of zinc oxide particles is in the range of 15 to 20 weight percent based on the weight of the composition, and the aluminum particles are a) in the range of 1 μm to 3 μm. ５０ Smaller particles having a volume-average particle size and b) D in the range of 7 μm to 15 μm ５０ A bimodal distribution of larger particles having a volume-average particle size, wherein the zinc oxide particles are in the range of 80 nm to 150 nm. ５０ The composition according to claim 5, having a volume-average particle size, wherein the concentration of the first treatment agent of formula 1 is in the range of 5 to 10 weight percent, and x is in the range of 50 to 150.

8. The second treatment agent in formula 2 is 【Transformation 3】 The composition according to claim 7, wherein the concentration of the second treatment agent of formula 2 is selected from the group consisting of the following, and the concentration of the second treatment agent of formula 2 is in the range of 0.1 to 0.5 weight percent based on the weight of the composition.

9. The second treatment agent in formula 2 is 【Chemistry 4】 The composition according to claim 7, wherein the concentration of the second treatment agent of formula 2 is in the range of 0.1 to 0.5 weight percent based on the weight of the composition.

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