A highly flexible heat-conducting structural adhesive organopolysiloxane composition and a method for producing the same

Abstract

This invention provides a high-toughness, thermally conductive adhesive organopolysiloxane composition comprising at least the following components (A)-(F): (A) an organosiloxane polymer having two or more alkenyl groups per molecule; (B) an organosiloxane polymer having two or more Si-H bonds per molecule; (C) a reactive siloxy-terminated polymer (RST); (D) a thermally conductive filler; (E) a cyclic polysiloxane adhesive accelerator; and (F) a platinum catalyst. This invention utilizes a reactive siloxy-terminated polymer (RST) and a cyclic polysiloxane adhesive accelerator to enhance the interfacial compatibility of organic and inorganic materials, reduce viscosity, and promote interfacial adhesion. Simultaneously, both components can participate in the formation of the overall organic material's cross-linked network, enabling the inorganic filler and cyclic structure to effectively reinforce and toughen the composite material. This invention is suitable for adhesive applications in thermal management systems requiring high toughness, high thermal conductivity, and high reliability.

Description

Technical fields:

[0001] This invention relates to a high-toughness thermally conductive adhesive organic polysiloxane composition and its preparation method, belonging to the fields of thermosetting, bonding and sealing, and heat dissipation solutions. Background technology:

[0002] Due to their excellent heat resistance, cold resistance, dielectric properties, ozone resistance, and atmospheric aging resistance, silicone materials have a wide operating temperature range, capable of long-term use from -60℃ (or lower) to +250℃ (or higher). They have gained widespread attention and application in various industries, especially in the thermal interface materials industry, where silicone thermal interface materials have occupied a dominant position, including thermal grease, thermal gel, thermal adhesive silicone, etc.

[0003] For thermally conductive silicon materials, surface treatment technology for thermally conductive fillers has always been one of the key technologies of greatest concern to industry professionals. This is because surface treatment of thermally conductive fillers can solve several major problems: effectively reducing the viscosity after filling, allowing for a greater filler loading and thus improving the thermal conductivity; and effectively improving the compatibility between inorganic fillers and organic resins, thereby enhancing the reliability of thermally conductive composite materials. However, while most treatment agents can effectively improve the compatibility between inorganic fillers and organic resins and reduce the viscosity of thermally conductive products, the lack of chemical bonds between the treatment agent and the resin system often leads to adverse effects on the mechanical properties of the product in most cases.

[0004] This invention aims to introduce a treatment agent using reactive silaneoxymethylene-terminated polymer (RST) as a thermally conductive filler. On the one hand, it effectively achieves the two treatment objectives mentioned above. Simultaneously, the reactive functional groups allow RST to participate in the formation of the cross-linked network of the overall organic material. Through the close chemical interaction between RST and the thermally conductive filler, both components effectively enhance the mechanical toughness of the composite material. Furthermore, it enables the thermally conductive composite material to maintain excellent high-temperature and high-humidity resistance even when using easily hydrolyzed aluminum nitride. With the addition of a cyclic polysiloxane adhesive accelerator, it effectively meets the structural bonding application requirements of thermal management systems with high toughness, high thermal conductivity, and high reliability. Summary of the Invention:

[0005] The purpose of this invention is to provide a high-toughness, thermally conductive adhesive organic polysiloxane composition and its preparation method, suitable for thermal management system bonding applications requiring high toughness, high thermal conductivity, and high reliability, such as heat sink bonding for integrated circuit packaging chips. This invention uses a reactive silaneoxymethylene-terminated polymer (RST) and a cyclic polysiloxane bonding accelerator as a treatment agent for the thermally conductive filler and an interfacial bonding accelerator, respectively. On the one hand, it achieves the functions of traditional thermally conductive filler treatment agents and interfacial bonding accelerators: increasing the interfacial compatibility of organic and inorganic materials, reducing viscosity, and promoting interfacial bonding. On the other hand, both components can participate in the formation of the overall organic material cross-linking network, making the inorganic filler and the cyclic structure effectively a reinforcing and toughening structure for the composite material, contributing to the mechanical toughening of the composite material. Simultaneously, this invention discloses a suitable treatment process for the thermally conductive filler and a preparation method for the composition, which helps RST and the thermally conductive filler form a tight chemical reaction, effectively improving the high-temperature and high-humidity resistance of the composite material.

[0006] The high-toughness thermally conductive adhesive organopolysiloxane composition of the present invention comprises at least the following components (A)-(F):

[0007] (A) 5-35 parts of organosiloxane polymers having 2 or more alkenyl groups per molecule;

[0008] (B) 0.1-10 parts of organosiloxane polymers with two or more Si-H bonds per molecule;

[0009] (C) 0.05-5 parts of reactive silaneoxy-terminated polymer (RST);

[0010] (D) 55-95 parts of thermally conductive filler;

[0011] (E) 0.05-2 parts of cyclic polysiloxane adhesive accelerator;

[0012] (F) Platinum catalyst 0.01-1 part;

[0013] Component (A) is an organosiloxane polymer with two or more alkenyl groups per molecule, and its general structural formula is (R 1 R 2 2SiO 1 / 2 (R) 1 R 2 SiO 2 / 2 ) a (R 2 SiO 3 / 2 ) b (SiO 4 / 2 ) c , where R 1 R 2Each group independently represents an unsubstituted or substituted monovalent hydrocarbon group. Preferably, the monovalent hydrocarbon group has 1 to 10 carbon atoms, particularly 1 to 6. Examples include: lower alkyl groups such as methyl, ethyl, propyl, and isopropyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl; alkane groups containing dilute bonds such as vinyl and propenyl; or groups obtained by substituting some or all of the hydrogen atoms of the above groups with halogen atoms, cyano groups, etc., such as chloromethyl and cyanoethyl. More preferably, groups derived from methyl, ethyl, vinyl, phenyl, etc., and R... 1 and R 2 At least one group is vinyl. a = 0 to 180 (excluding 0), b = 0 to 2, c = 0 to 2, a+b+c = 1 to 180.

[0014] Component (B) is an organosiloxane polymer with two or more Si-H bonds per molecule, and its general structural formula is (R 1 R 2 2SiO 1 / 2 (R) 1 R 2 SiO 2 / 2 ) m (R 2 SiO 3 / 2 ) n (SiO 4 / 2 ) x , where R 1 R 2 Each group independently represents an unsubstituted or substituted monovalent hydrocarbon group. Preferably, the monovalent hydrocarbon group has 1 to 10 carbon atoms, particularly 1 to 6. Examples include: lower alkyl groups such as methyl, ethyl, propyl, and isopropyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl; alkane groups containing dilute bonds such as vinyl and propenyl; or groups obtained by substituting some or all of the hydrogen atoms of the above groups with halogen atoms, cyano groups, etc., such as chloromethyl and cyanoethyl. More preferably, groups derived from methyl, ethyl, phenyl, etc., and R... 1 and R 2 At least one of the groups is H. m = 0 to 35, n = 0 to 2, c = 0 to 0.5, m+n+c = 1 to 35.

[0015] The component (C), a reactive silaneoxy-terminated polymer (RST), has the following structure:

[0016]

[0017] Among them, R 1 R 2Each group independently represents an unsubstituted or substituted monovalent hydrocarbon group. Preferably, the monovalent hydrocarbon group has 1 to 10 carbon atoms, particularly 1 to 6. Examples include: lower alkyl groups such as methyl, ethyl, propyl, and isopropyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl; alkane groups containing dilute bonds such as vinyl and propenyl; or groups obtained by substituting some or all hydrogen atoms of the above groups with halogen atoms, cyano groups, etc., such as chloromethyl and cyanoethyl. More preferably, groups derived from methyl, ethyl, and phenyl groups are preferred. R3 is a reactive group capable of participating in hydrosilylation, such as alkane groups containing dilute bonds such as vinyl and propenyl, or H. y1, y2, y3, and y4 are independent of each other and can all be integers from 0 to 50, and y1 + y2 + y3 + y4 = 0 to 50.

[0018] The component (D) thermally conductive filler is a common commercially available thermally conductive filler, such as alumina, aluminum hydroxide, aluminum nitride, and aluminum powder. It can be used alone or in combination with other thermally conductive fillers. There are no special requirements for the morphology of the thermally conductive filler; it can be spherical, or irregularly shaped blocks or sheets. The maximum particle size of the thermally conductive filler does not exceed 80 μm.

[0019] The component (E) is a cyclic polysiloxane adhesive promoter. The "cyclic" part comes from the cyclic polysiloxane, which is a ring with 4-8 Si-O segments. One side of the Si atom is a monovalent hydrocarbon group such as methyl, ethyl, propyl, or isopropyl, while the other side can be a polar adhesive promoting group such as a siloxane group, epoxy group, or acyl group, or a monovalent hydrocarbon group such as methyl, ethyl, propyl, isopropyl, vinyl, propenyl, or H. Each molecule of cyclic polysiloxane adhesive promoter must contain two or more polar adhesive promoting groups such as siloxane groups, epoxy groups, or acyl groups, and must contain one or more reactive groups such as vinyl, propenyl, or H that can participate in hydrosilylation.

[0020] The component (F) platinum catalyst is one or a mixture of several of the following: platinum chloride, alcohol-modified platinum chloride, platinum chloride and diene complexes, platinum-olefin complexes, platinum-carbonyl complexes such as platinum bis(acetoacetate) or platinum bis(acetylacetone), platinum chloride-alkenylsiloxane complexes such as platinum chloride-divinyltetramethyldisiloxane complex or platinum chloride-tetravinyltetramethylcyclotetrasiloxane, platinum-alkenylsiloxane complexes such as platinum-divinyltetramethyldisiloxane complex or platinum-tetravinyltetramethylcyclotetrasiloxane, platinum chloride and ethynyl alcohol complexes, and encapsulated platinum catalysts.

[0021] The preparation method of the high-toughness thermally conductive adhesive organopolysiloxane composition of the present invention is divided into two parts: the first step is the pretreatment of thermally conductive filler, and the second step is the preparation of the high-toughness thermally conductive adhesive organopolysiloxane composition.

[0022] The pretreatment process for thermally conductive fillers is as follows: Weigh out component (A), an organosiloxane polymer with two or more alkenyl groups per molecule, and component (C), a reactive siloxy-terminated polymer (RST). Mix and stir until homogeneous. Add a certain amount of ethanol solution of deionized water (deionized water content is 1‰~10%) and stir until homogeneous. Then, add component (D), the thermally conductive filler, to the reactor. After mixing until homogeneous, heat to 80~150℃ and maintain positive pressure for high-temperature treatment for 2~6 hours. Subsequently, treat under vacuum at 100~150℃ for 1~3 hours to obtain the pretreated thermally conductive filler. The amount of ethanol solution of deionized water added needs to be adjusted according to the hydroxyl content on the surface of the thermally conductive filler, and is generally 0.1-5 times that of component (C), the reactive siloxy-terminated polymer (RST).

[0023] After cooling the thermally conductive filler pretreatment material to below 40°C, add component (E) cyclic polysiloxane adhesive promoter and component (F) platinum catalyst. Depending on the operation time, appropriate inhibitors can be added. After mixing and stirring evenly, add component (B) organosiloxane polymer with two or more Si-H bonds per molecule. After stirring evenly, a high-toughness thermally conductive adhesive organosiloxane composition is obtained.

[0024] The beneficial effects of this preparation process are as follows: Pre-treating the thermally conductive filler increases the interfacial compatibility between organic and inorganic materials, which is more conducive to reducing the overall viscosity of the product system. It also helps form chemical bonds that tightly bind the component (C) to the thermally conductive filler interface, further enhancing the toughness of the final product. Furthermore, our research found that a positive pressure treatment temperature of 80–150°C is necessary; lower treatment temperatures are detrimental to improving the product's high-temperature and high-humidity resistance. Secondly, the cyclic polysiloxane adhesive accelerator (component E) must be added later, not during filler pre-treatment. This is not only to prevent it from competing with component (C) for bonding on the filler surface, but also because adding component (E) during filler pre-treatment would decrease the product's high-temperature and high-humidity resistance.

[0025] Based on this patented invention, adjustments can be made to meet the corresponding application requirements: such as adding fluorescent agents to provide fluorescence detection capabilities, adding color pastes and carbon black to adjust the appearance color, and adding fumed silicon and thixotropic additives to adjust rheological properties, etc.

[0026] This invention provides a high-toughness, thermally conductive adhesive organic polysiloxane composition and its preparation method, suitable for bonding applications in thermal management systems requiring high toughness, high thermal conductivity, and high reliability, such as bonding heat sink frames for integrated circuit packaging chips. The beneficial effects of this invention are as follows: This invention uses reactive silane-oxygen-terminated polymers (RST) and cyclic polysiloxane adhesive accelerators as treatment agents for thermally conductive fillers and interfacial bonding accelerators, respectively. On the one hand, it achieves the functions of traditional thermally conductive filler treatment agents and interfacial bonding accelerators: increasing the interfacial compatibility of organic and inorganic materials, reducing viscosity, and promoting interfacial bonding. On the other hand, both components can participate in the formation of the overall organic material cross-linking network, making the inorganic filler and cyclic structure effectively a reinforcing and toughening structure for the composite material, contributing to the mechanical toughening of the composite material. This invention discloses a suitable treatment process for the thermally conductive filler and a preparation method for the composition, which helps RST and the thermally conductive filler form a close chemical reaction, effectively improving the high-temperature and high-humidity resistance of the composite material. Detailed implementation method:

[0027] The following specific embodiments describe the principles and features of the present invention. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] Example 1

[0029] Weigh out 15 portions of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 60 (Vi represents vinyl), 2 parts (Vi(CH3)2SiO) 1 / 2 ) 0.2 ((CH3)3SiO 1 / 2 ) 0.8 (SiO 4 / 2 ) 1.2 0.5 parts of reactive silaneoxy-terminated polymer (RST-1, structural formula below) were mixed and stirred until homogeneous. Then, 0.2 parts of an ethanol solution of deionized water (deionized water content of 5‰) were added and stirred until homogeneous. Subsequently, 60.45 parts of spherical alumina with an average particle size of 30 μm and 20 parts of aluminum nitride with an average particle size of 5 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 100 °C and maintained under positive pressure for 3 hours. Subsequently, it was treated at 120 °C under vacuum and stirred for 1 hour to obtain the pretreated thermally conductive filler.

[0030]

[0031] After cooling the thermally conductive filler pretreatment material to below 40°C, add 0.5 parts of (E) cyclic polysiloxane adhesive accelerator-1 (structural formula below) and 0.05 parts of 5000ppm platinum-containing encapsulated platinum catalyst. After mixing and stirring evenly, add 1.5 parts of (CH3)3SiO 1 / 2 ((CH3)HSiO 2 / 2 ) 10 ((CH3)2SiO 2 / 2 ) 25 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0032]

[0033] Example 2

[0034] Weigh out 18.85 parts of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 30 ((CH3)2SiO 3 / 2 1 (Vi represents vinyl), 0.2 parts of reactive silaneoxy-terminated polymer (RST-2, structural formula below), were mixed and stirred until homogeneous. Then, 0.2 parts of an ethanol solution of deionized water (deionized water content was 1‰) were added and stirred until homogeneous. Subsequently, 74 parts of aluminum hydroxide with an average particle size of 20 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 80 °C and maintained under positive pressure for 6 hours. Subsequently, it was treated at 120 °C under vacuum and stirred for 1 hour to obtain the pretreated thermally conductive filler.

[0035]

[0036] After cooling the thermally conductive filler pretreatment material to below 40°C, add 1.0 part of (E) cyclic polysiloxane adhesive accelerator-2 (structural formula below), 0.05 parts of 5000ppm platinum-olefin siloxane complex, and 0.05 parts of methylbutynol. After mixing and stirring evenly, add 0.8 parts of (CH3)2HSiO. 1 / 2 (SiO 4 / 2 ) 0.8 And 5.0 parts (CH3)2HSiO 1 / 2 ((CH3)2SiO 2 / 2 ) 20 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0037]

[0038] Example 3

[0039] Weigh out 7.5 parts of Vi(CH3)2SiO1 / 2 (CH3)2SiO 2 / 2 ) 150 (Vi(CH3)2SiO 2 / 2 ) 10 (Vi represents vinyl), 2 parts (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 30 Three parts of reactive silaneoxy-terminated polymer (RST-3, structural formula below) were mixed and stirred until homogeneous. Then, 0.3 parts of an ethanol solution of deionized water (deionized water content of 5‰) were added and stirred until homogeneous. Subsequently, 20 parts of zinc oxide with an average particle size of 1 μm, 20 parts of aluminum nitride with an average particle size of 5 μm and 45 parts of aluminum powder with an average particle size of 8 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 120°C and maintained under positive pressure for 3 hours. Subsequently, it was treated at 150°C under vacuum with stirring for 3 hours to obtain the pretreated thermally conductive filler.

[0040]

[0041] After cooling the thermally conductive filler pretreatment material to below 40°C, add 0.3 parts of (E) cyclic polysiloxane adhesive accelerator-3 (structural formula below), 0.1 parts of 1-ethynyl-1-cyclohexanol, and 0.2 parts of 2000ppm platinum-olefin siloxane complex. After mixing and stirring evenly, add 1.9 parts of (CH3)2HSiO 1 / 2 ((CH3)2SiO 2 / 2 )7((CH3)HSiO 2 / 2 )1(CH3SiO 3 / 2 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0042]

[0043] Example 4

[0044] Weigh out 20 portions of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 60 (Vi represents vinyl), 10.9 parts (Vi(CH3)2SiO) 1 / 2 ) 0.2 ((CH3)3SiO 1 / 2 ) 0.8 (SiO 4 / 2 ) 1.2One part of a reactive silaneoxy-terminated polymer (RST-4, structural formula below) was mixed and stirred until homogeneous. Then, four parts of an ethanol solution of deionized water (1‰ deionized water content) were added and stirred until homogeneous. Subsequently, 60 parts of alumina with an average particle size of 10 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 100°C and maintained under positive pressure for 3 hours. Afterward, it was treated at 120°C under vacuum and stirred for 1 hour to obtain the pretreated thermally conductive filler.

[0045]

[0046] After cooling the thermally conductive filler pretreatment material to below 40°C, add 1.8 parts of (E) cyclic polysiloxane adhesive accelerator-4 (structural formula below) and 0.8 parts of 1000ppm platinum-containing encapsulated platinum catalyst. After mixing and stirring evenly, add 4 parts of (CH3)2HSiO 1 / 2 (SiO 4 / 2 ) 0.8 and 1.5 parts (CH3)2HSiO 1 / 2 ((CH3)2SiO 2 / 2 ) 20 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0047]

[0048] Comparative Example 1

[0049] Weigh out 15 portions of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 60 (Vi represents vinyl), 2 parts (Vi(CH3)2SiO) 1 / 2 ) 0.2 ((CH3)3SiO 1 / 2 ) 0.8 (SiO 4 / 2 ) 1.2 0.5 parts of reactive silaneoxy-terminated polymer (RST-1) were mixed and stirred until homogeneous. Then, 0.2 parts of an ethanol solution of deionized water (with a deionized water content of 5‰) were added and stirred until homogeneous. Subsequently, 60.45 parts of spherical alumina with an average particle size of 30 μm and 20 parts of aluminum nitride with an average particle size of 5 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 60 °C and maintained under positive pressure for 3 hours. Subsequently, it was treated at 120 °C under vacuum with stirring for 1 hour to obtain the pretreated thermally conductive filler.

[0050] After cooling the thermally conductive filler pretreatment material to below 40°C, add 0.5 parts of (E) cyclic polysiloxane adhesion promoter-1 and 0.05 parts of 5000ppm platinum-containing encapsulated platinum catalyst. After mixing and stirring evenly, add 1.5 parts of (CH3)3SiO 1 / 2 ((CH3)HSiO 2 / 2 ) 10 ((CH3)2SiO 2 / 2 ) 25 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0051] Comparative Example 2

[0052] Weigh out 15 portions of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 60 (Vi represents vinyl), 2 parts (Vi(CH3)2SiO) 1 / 2 ) 0.2 ((CH3)3SiO 1 / 2 ) 0.8 (SiO 4 / 2 ) 1.2 0.5 parts of silaneoxy-terminated polymer (structural formula below) were mixed and stirred until homogeneous. Then, 0.2 parts of an ethanol solution of deionized water (deionized water content of 5‰) were added and stirred until homogeneous. Subsequently, 60.45 parts of spherical alumina with an average particle size of 30 μm and 20 parts of aluminum nitride with an average particle size of 5 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 100 °C and maintained under positive pressure for 3 hours. Subsequently, it was treated at 120 °C under vacuum and stirred for 1 hour to obtain the pretreated thermally conductive filler.

[0053]

[0054] After cooling the thermally conductive filler pretreatment material to below 40°C, add 0.5 parts of (E) cyclic polysiloxane adhesion promoter-1 and 0.05 parts of 5000ppm platinum-containing encapsulated platinum catalyst. After mixing and stirring evenly, add 1.5 parts of (CH3)3SiO 1 / 2 ((CH3)HSiO 2 / 2 ) 10 ((CH3)2SiO 2 / 2 ) 25 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0055] Comparative Example 3

[0056] Weigh out 18.85 parts of (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO2 / 2 ) 30 ((CH3)2SiO 3 / 2 1 (Vi represents vinyl), 0.2 parts of reactive silaneoxy-terminated polymer (RST-2, structural formula below), were mixed and stirred until homogeneous. Then, 0.1 parts of an ethanol solution of deionized water (deionized water content was 1‰) were added and stirred until homogeneous. Subsequently, 74 parts of aluminum hydroxide with an average particle size of 20 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 80 °C and maintained under positive pressure for 6 hours. Subsequently, it was treated at 120 °C under vacuum and stirred for 1 hour to obtain the pretreated thermally conductive filler.

[0057]

[0058] After cooling the thermally conductive filler pretreatment material to below 40°C, add 1.0 part of polysiloxane adhesion promoter (structural formula as follows), 0.05 part of 5000ppm platinum-olefin siloxane complex, and 0.05 part of methylbutynol. After mixing and stirring evenly, add 0.8 parts of (CH3)2HSiO. 1 / 2 (SiO 4 / 2 ) 0.8 And 5.0 parts (CH3)2HSiO 1 / 2 ((CH3)2SiO 2 / 2 ) 20 After thorough mixing, a high-toughness, thermally conductive adhesive organopolysiloxane composition is obtained.

[0059]

[0060] Comparative Example 4

[0061] Weigh out 7.5 parts of Vi(CH3)2SiO 1 / 2 (CH3)2SiO 2 / 2 ) 150 (Vi(CH3)2SiO 2 / 2 ) 10 (Vi represents vinyl), 2 parts (Vi(CH3)2SiO) 1 / 2 (CH3)2SiO 2 / 2 ) 30 Three parts of reactive silaneoxy-terminated polymer (RST-3) and 0.3 parts of (E) cyclic polysiloxane adhesive accelerator-3 were mixed and stirred until homogeneous. Then, 0.3 parts of an ethanol solution of deionized water (with a deionized water content of 5‰) were added and stirred until homogeneous. Subsequently, 20 parts of zinc oxide with an average particle size of 1 μm, 20 parts of aluminum nitride with an average particle size of 5 μm and 45 parts of aluminum powder with an average particle size of 8 μm were added to the reactor and mixed until homogeneous. The mixture was then heated to 120°C and maintained under positive pressure for 3 hours. Subsequently, it was treated at 150°C under vacuum with stirring for 3 hours to obtain the thermally conductive filler pretreated material.

[0062]

[0063] After cooling the pretreated thermally conductive filler to below 40°C, add 0.1 parts of 1-ethynyl-1-cyclohexanol and 0.2 parts of 2000ppm platinum-olefin siloxane complex, mix and stir evenly, then add 1.9 parts of (CH3)2HSiO 1 / 2 ((CH3)2SiO 2 / 2 )7((CH3)HSiO 2 / 2 )1(CH3SiO 3 / 2 After thorough mixing, a high-toughness, thermally conductive adhesive organic polysiloxane composition is obtained.

[0064] The test items and test conditions are as follows:

[0065] 1. Heat curing conditions: 150℃ * 1h;

[0066] 2. Tensile strength and elongation at break tests shall be conducted in accordance with GB / T528-2009;

[0067] 3. Overlap shear strength test: the overlap area is (25±0.25)mm*(12.5±0.25)mm, and the thickness is 0.15mm;

[0068] 4. The instrument used for testing thermal conductivity is the Hot DISC thermal conductivity meter;

[0069] 5. UHAST aging test conditions are: 130℃ * 85%RH * 1 atm;

[0070] Table 1 Summary of test results after preparation of the examples and comparative examples.

[0071]

[0072] As can be seen from Table 1, the high-toughness thermally conductive adhesive organopolysiloxane composition of the present invention, after curing at 150℃ for 1 hour, has a bulk strength of over 2 MPa while possessing thermal conductivity. Even when the thermal conductivity reaches 3 MPa W / mk, it still has an elongation of 30%, exhibiting high toughness. After undergoing UHAST aging conditions for 192 hours, the tensile strength, elongation at break, and lap shear strength show only a slight decrease. This composition can meet the bonding requirements of thermal management systems that require high toughness, high thermal conductivity, and high reliability.

[0073] Compared with Example 1, when the powder treatment temperature is lower, it is not conducive to the formation of a tight chemical reaction between RST and thermally conductive filler. Although the initial performance after curing is not significantly affected, the elongation decreases significantly after aging under high temperature, high humidity, and high pressure reliability conditions.

[0074] Compared with Example 1, the powder treatment agent used in Comparative Example 2 does not contain addition-curing reactive functional groups. As a result, both the powder treatment agent and the powder particles are components independent of the cross-linking network and cannot interact with the cross-linking network. Therefore, they cannot achieve the effect of reinforcement and toughening, and the tensile strength, elongation at break and lap shear strength all show a significant decrease.

[0075] Compared with Example 2, Comparative Example 3 used a non-cyclic polysiloxane adhesive accelerator instead of a polysiloxane adhesive accelerator containing a cyclic structure. The tensile strength and elongation at break both decreased slightly, indicating that the easily deformable cyclic structure in the adhesive accelerator helps to form a chain effect, thereby helping to improve the strength and elongation of the entire system.

[0076] Compared to Example 3, Comparative Example 4, which simultaneously added the cyclic polysiloxane adhesive accelerator and the powder treatment agent RST, showed little difference in tensile strength and elongation at break after curing, but the lap shear strength was slightly lower. Furthermore, after high-temperature, high-pressure, and high-humidity aging, the decrease in elongation at break and lap shear strength was also greater. This indicates that the simultaneous addition of the cyclic polysiloxane adhesive accelerator and the powder treatment agent RST easily creates a competitive relationship on the bonding surface of the filler. On the one hand, this results in poor powder coating, leading to poor high-temperature and high-humidity resistance; on the other hand, it also consumes the active adhesive groups of the adhesive accelerator, causing poor interfacial adhesion. After aging, this makes the filler more susceptible to erosion, leading to interfacial adhesion failure and a significant decrease in bond strength.

Claims

1. A high-toughness, thermally conductive, adhesive organopolysiloxane composition, characterized in that, It contains at least the following components (A)-(F) by weight: (A) 5-35 parts of organosiloxane polymer having 2 or more alkenyl groups per molecule; (B) 0.1-10 parts of organosiloxane polymer having 2 or more Si-H bonds per molecule; (C) 0.05-5 parts of reactive siloxy-terminated polymer; (D) 55-95 parts of thermally conductive filler; (E) 0.05-2 parts of cyclic polysiloxane adhesive accelerator; (F) 0.01-1 part of platinum catalyst; The preparation method of the high-toughness thermally conductive structure adhesive organopolysiloxane composition is divided into two parts: the first step is the pretreatment of thermally conductive filler, and the second step is the preparation of the high-toughness thermally conductive structure adhesive organopolysiloxane composition. The process for pretreatment of thermally conductive fillers is as follows: Weigh out component (A), an organosiloxane polymer with at least two alkenyl groups per molecule, and component (C), a reactive siloxy-terminated polymer (RST). After mixing and stirring evenly, add a certain amount of ethanol solution of deionized water, wherein the content of deionized water is 1‰ to 10%, and stir and mix evenly. Then, add component (D), the thermally conductive filler, into the reactor, mix evenly, raise the temperature to 80 to 150°C, maintain positive pressure and high temperature treatment for 2 to 6 hours, and then treat under vacuum and stirring at 100 to 150°C for 1 to 3 hours to obtain the pretreated thermally conductive filler. The amount of ethanol solution of deionized water added needs to be adjusted according to the amount of hydroxyl content on the surface of the thermally conductive filler, and is 0.1 to 5 times that of component (C), the reactive siloxy-terminated polymer (RST). After cooling the thermally conductive filler pretreatment material to below 40°C, component (E) cyclic polysiloxane adhesive promoter and component (F) platinum catalyst are added. After mixing and stirring evenly, component (B) organosiloxane polymer with at least 2 Si-H bonds per molecule is added. After stirring evenly, a high-toughness thermally conductive adhesive organosiloxane composition is obtained.

2. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 1, characterized in that, Component (A) is an organosiloxane polymer with two or more alkenyl groups per molecule, and its general structural formula is (R 1 R 2 2SiO 1 / 2 (R) 1 R 2 SiO 2 / 2 ) a (R 2 SiO 3 / 2 ) b (SiO 4 / 2 ) c Among them, R 1 R 2 Each of the following is a single compound: methyl, ethyl, vinyl, or phenyl, and R 1 and R 2 One or two groups are vinyl groups; a = 0 to 180 excluding 0, b = 0 to 2, c = 0 to 2, a+b+c = 1 to 180.

3. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 1, characterized in that, Component (B) is an organosiloxane polymer with two or more Si-H bonds per molecule, and its general structural formula is (R 1 R 2 2SiO 1 / 2 (R) 1 R 2 SiO 2 / 2 ) m (R 2 SiO 3 / 2 ) n (SiO 4 / 2 ) x , where R 1 R 2 Each of the following is a methyl, ethyl, or phenyl compound, and R 1 and R 2 One or two of the groups are H groups; m = 0 to 35, n = 0 to 2, c = 0 to 0.5, m+n+c = 1 to 35.

4. The high-toughness thermally conductive structural adhesive organopolysiloxane composition according to claim 1, characterized in that, The reactive silaneoxy-terminated polymer of component (C) has the following structure: Among them, R 1 R 2 R1, R2, R3, and R4 are all of the following: methyl, ethyl, and phenyl; R3 is vinyl, propenyl, or H group; y1, y2, y3, and y4 are integers, and y1+y2+y3+y4=0~50.

5. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 1, characterized in that, The thermally conductive filler component (D) is one or more of alumina, aluminum hydroxide, aluminum nitride, and aluminum powder, and the particle size of the thermally conductive filler is less than or equal to 80 μm.

6. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 1, characterized in that, The component (E) cyclic polysiloxane adhesive promoter is a ring with 4-8 Si-O segments. One side group of the Si atom is one of methyl, ethyl, propyl, and isopropyl, and the other side group contains one of siloxane group, epoxy group, acyl group, methyl, ethyl, propyl, isopropyl, vinyl, propenyl, and H. The cyclic polysiloxane adhesive promoter molecule contains two or more siloxane group, epoxy group, and acyl group, and contains one or more vinyl, propenyl, and H groups.

7. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 1, characterized in that, The component (F) platinum catalyst is one or a mixture of several of the following: platinum chloride, alcohol-modified platinum chloride, platinum chloride and diene complex, platinum-olefin complex, platinum-carbonyl complex, platinum chloride-alkenylsiloxane complex, platinum-alkenylsiloxane complex, platinum chloride and ethynyl alcohol complex, and encapsulated platinum catalyst.

8. The high-toughness thermally conductive adhesive organopolysiloxane composition according to claim 7, characterized in that, The platinum-carbonyl complex is platinum bis(acetoacetate) or platinum bis(acetylacetone); the platinum chloride-alkenylsiloxane complex is platinum chloride-divinyltetramethyldisiloxane complex or platinum chloride-tetravinyltetramethylcyclotetrasiloxane; the platinum-alkenylsiloxane complex is platinum-divinyltetramethyldisiloxane complex or platinum-tetravinyltetramethylcyclotetrasiloxane.

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