A heat conductive adhesive composition and a method for preparing the same

Abstract

The application provides a heat-conducting adhesive composition, which is prepared from the following components in parts by weight: polyol 56-60 parts, diisocyanate 45-48 parts, chain extender 6-9 parts, catalyst 0.4-0.8 parts, heat-conducting filler 52-56 parts, silane coupling agent 1-2 parts, toughening agent 4-7 parts, and solvent 20-24 parts. The application also provides a preparation method of the heat-conducting adhesive composition. The heat-conducting adhesive composition provided by the application has good heat-conducting performance, heat resistance and impact resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of heat-conducting glue compositions and preparation method thereof. BACKGROUND

[0002] In the mounting production process of electronic components, it is usually necessary to bond and fix electronic components, so that electronic structural glue plays an indispensable role. At present, the adhesive used for bonding electronic components includes acrylic glue, silicone, epoxy resin glue, polyurethane glue and the like. Among them, polyurethane structural glue has excellent bonding performance and electrical insulation performance, and is widely used in the bonding of electronic components.

[0003] In recent years, various electronic components have higher and higher power and smaller and smaller size. With the increase of power, electronic components have higher and higher technical requirements for heat dissipation and packaging. However, the ordinary polyurethane glue has poor heat resistance and low thermal conductivity, and the heat conduction effect is limited, which cannot effectively conduct the heat generated by electronic components. The accumulation of heat can easily cause the failure of polyurethane glue, fire and combustion, and also reduce the reliability and service life of electronic equipment. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a kind of heat-conducting glue compositions, it has good heat-conducting performance, heat resistance and impact resistance.

[0005] To solve the above technical problems, the technical scheme of the present application is:

[0006] A kind of heat-conducting glue compositions is made of the following components by weight: polyol 56-60 parts, diisocyanate 45-48 parts, chain extender 6-9 parts, catalyst 0.4-0.8 parts, heat-conducting filler 52-56 parts, silane coupling agent 1-2 parts, toughening agent 4-7 parts, solvent 20-24 parts.

[0007] Further, the polyol of the present application is composed of castor oil polyol and polytetrahydrofuran diol in a weight ratio of 1:1.

[0008] Further, the diisocyanate of the present application is hexamethylene diisocyanate.

[0009] Further, the chain extender of the present application is 1,4-butanediol.

[0010] Further, the catalyst of the present application is stannous octoate.

[0011] Further, the heat-conducting filler of the present application is made by the following steps:

[0012] (1) magnesium oxide, hafnium tetrachloride are added into deionized water and stirred for 20-30 minutes to obtain a mixed solution, the pH value is adjusted to 9 by using ammonia water, and then stirred for 10-20 minutes to obtain a suspension, the suspension is filtered to obtain a precipitate, the precipitate is washed with deionized water for 3 times, and then placed in a hydrothermal kettle, heated to 350 DEG C, and then kept for 5-7 hours, and then naturally cooled to room temperature to obtain solid material I, the solid material I is ground and then passed through a 200 mesh screen to obtain a composite powder;

[0013] (2) the carbon black, anhydrous ethanol, grinding balls, and the composite powder obtained in step (1) are added into a planetary ball mill, ball milled for 2-3 hours to obtain a slurry, the slurry is dried to obtain a ball milled powder, the ball milled powder is placed in a tube furnace, heated to 1400 DEG C under an argon atmosphere, kept for 2-3 hours, and then cooled to room temperature to obtain solid material II, the solid material II is ground and then passed through a 200 mesh screen to obtain a heat conductive filler.

[0014] Further, in the preparation step (1) of the heat conductive filler, the weight ratio of magnesium oxide, hafnium tetrachloride and deionized water is 2:1:10, the concentration of ammonia water is 1 mol / L, and the heating rate of the hydrothermal kettle is 5 DEG C / min; in step (2), the grinding balls are silicon carbide grinding balls, the weight ratio of carbon black, anhydrous ethanol, grinding balls and the composite powder obtained in step (1) is 1:6:5:2, the drying temperature is 80 DEG C, the drying time is 24 hours, and the heating rate of the tube furnace is 10 DEG C / min.

[0015] Further, the silane coupling agent is vinyltrimethoxysilane.

[0016] Further, the toughening agent is 2-pyrrolidine methyl acetate, and the solvent is composed of N-methyl pyrrolidone and ethyl acetate with a weight ratio of 1:1.

[0017] Another technical problem to be solved by the present application is to provide a preparation method of the heat conductive adhesive composition.

[0018] To solve the above technical problems, the technical scheme is as follows:

[0019] A preparation method of a heat conductive adhesive composition, comprising the following steps:

[0020] S1. each component is weighed by weight parts, the polyol is placed in a reaction bottle with a vacuum degree of 0.09 MPa, heated to 100-110 DEG C, vacuum dehydrated for 1-2 hours, and then cooled to 70-80 DEG C;

[0021] S2. the diisocyanate is added into the reaction bottle, stirred at a speed of 200-300 revolutions per minute for 2-3 hours, and then cooled to 60-70 DEG C;

[0022] S3. Add the other components to the reaction flask and stir at 200-300 rpm for 1-2 hours to obtain the thermally conductive adhesive composition.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention prepares a composite powder with a hafnium oxide-coated magnesium oxide structure by hydrothermal methods and other operations with magnesium oxide and hafnium tetrachloride. Then, using carbon black as a carbon source, the composite powder is reduced in situ by carbothermal reduction to obtain a thermally conductive filler with a hafnium carbide-coated magnesium carbide structure. Magnesium carbide has a high thermal conductivity and good high temperature resistance, but its impact resistance is poor. The hafnium carbide coating layer makes up for this defect. Moreover, hafnium carbide itself also has a high thermal conductivity and good high temperature resistance. Therefore, the thermally conductive filler prepared by this invention can effectively improve the thermal conductivity, heat resistance and impact resistance of the thermally conductive adhesive composition. In addition, the toughening agent used in this invention, methyl 2-pyrrolidine acetate, can further improve the impact resistance and heat resistance of the thermally conductive adhesive composition. Detailed Implementation

[0025] The present invention will now be described in detail with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0026] Example 1

[0027] The thermally conductive adhesive composition is made from the following components in parts by weight: 58 parts polyol, 47 parts diisocyanate, 8 parts chain extender, 0.6 parts catalyst, 54 parts thermally conductive filler, 1.5 parts silane coupling agent, 6 parts toughening agent, and 22 parts solvent. The polyol is composed of castor oil polyol and polytetrahydrofuran diol in a 1:1 weight ratio; the diisocyanate is hexamethylene diisocyanate; the chain extender is 1,4-butanediol; the catalyst is stannous octoate; the silane coupling agent is vinyltrimethoxysilane; the toughening agent is methyl 2-pyrrolidone acetate; and the solvent is composed of N-methylpyrrolidone and ethyl acetate in a 1:1 weight ratio.

[0028] The thermally conductive filler is made by the following steps:

[0029] (1) Add magnesium oxide and hafnium tetrachloride to deionized water and stir for 25 minutes to obtain a mixed solution. The weight ratio of magnesium oxide, hafnium tetrachloride and deionized water is 2:1:10. Adjust the pH value to 9 with 1 mol / L ammonia water and stir for 15 minutes to obtain a suspension. Filter the suspension to obtain a precipitate. Wash the precipitate three times with deionized water and place it in a hydrothermal reactor. Heat the temperature to 350°C at a heating rate of 5°C / min and keep it at that temperature for 6 hours. After naturally cooling to room temperature, obtain solid one. Grind solid one and pass it through a 200-mesh sieve to obtain composite powder.

[0030] (2) Put the carbon black, anhydrous ethanol, silicon carbide ball and the composite powder obtained in step (1) in a planetary ball mill in a weight ratio of 1:6:5:2, and ball mill for 2.5 hours to obtain a slurry. The slurry is dried at 80℃ for 24 hours to obtain a ball milled powder. The ball milled powder is placed in a tube furnace, and heated to 1400℃ at a temperature rising rate of 10℃ / min under an argon atmosphere, and then kept for 2.5 hours. The furnace is cooled to room temperature to obtain solid material two. The solid material two is ground and passed through a 200 mesh sieve to obtain the heat conducting filler.

[0031] The preparation method of Example 1 comprises the following steps:

[0032] S1. Weigh each component by weight parts, and place the polyol in a reaction bottle with a vacuum degree of 0.09 MPa. Heat to 105℃ and vacuum dehydrate for 1.5 hours, then cool to 75℃;

[0033] S2. Add diisocyanate to the reaction bottle and stir at 200 rpm for 2.5 hours, then cool to 65℃;

[0034] S3. Add other components to the reaction bottle and stir at 200 rpm for 1.5 hours to obtain a heat conducting adhesive composition.

[0035] Example 2

[0036] The heat conducting adhesive composition is made of the following components by weight parts: polyol 60 parts, diisocyanate 48 parts, chain extender 9 parts, catalyst 0.8 parts, heat conducting filler 56 parts, silane coupling agent 2 parts, toughening agent 7 parts, and solvent 24 parts. The polyol is composed of castor oil polyol and polytetrahydrofuran diol in a weight ratio of 1:1, the diisocyanate is hexamethylene diisocyanate, the chain extender is 1,4-butanediol, the catalyst is stannous octoate, the silane coupling agent is vinyl trimethoxysilane, the toughening agent is 2-pyrrolidine methyl acetate, and the solvent is composed of N-methyl pyrrolidone and ethyl acetate in a weight ratio of 1:1.

[0037] The heat conducting filler is made by the following steps:

[0038] (1) Add magnesium oxide and hafnium tetrachloride to deionized water and stir for 30 minutes to obtain a mixed solution. The weight ratio of magnesium oxide, hafnium tetrachloride and deionized water is 2:1:10. Adjust the pH value to 9 with ammonia water of 1 mol / L concentration, and stir for 20 minutes to obtain a suspension. The suspension is filtered to obtain a precipitate. The precipitate is washed with deionized water for 3 times, and then placed in an autoclave. Heat to 350℃ at a temperature rising rate of 5℃ / min, and then keep for 7 hours. Naturally cool to room temperature to obtain solid material one. Grind the solid material one and pass through a 200 mesh sieve to obtain a composite powder;

[0039] (2) Put the carbon black, anhydrous ethanol, silicon carbide ball and the composite powder obtained in step (1) in a planetary ball mill in a weight ratio of 1:6:5:2, and ball mill for 3 hours to obtain a slurry. Dry the slurry at 80°C for 24 hours to obtain a ball milled powder. Put the ball milled powder into a tube furnace, and heat to 1400°C at a temperature rising rate of 10°C / min under an argon atmosphere, and then keep the temperature for 3 hours. Cool the furnace to room temperature to obtain solid material two. Grind the solid material two and pass it through a 200-mesh sieve to obtain the heat-conducting filler.

[0040] The preparation method of Example 2 comprises the following steps:

[0041] S1. Weigh each component by weight parts, and place the polyol in a reaction bottle with a vacuum degree of 0.09 MPa. Heat to 100°C and vacuum dehydrate for 2 hours, and then cool to 70°C;

[0042] S2. Add diisocyanate to the reaction bottle, and stir at a speed of 300 rpm for 3 hours, and then cool to 60°C;

[0043] S3. Add other components to the reaction bottle, and stir at a speed of 300 rpm for 2 hours to obtain a heat-conducting adhesive composition.

[0044] Example 3

[0045] The heat-conducting adhesive composition is made of the following components by weight parts: polyol 56 parts, diisocyanate 45 parts, chain extender 6 parts, catalyst 0.4 parts, heat-conducting filler 52 parts, silane coupling agent 1 part, toughening agent 4 parts, and solvent 20 parts. The polyol is composed of castor oil polyol and polytetrahydrofuran diol in a weight ratio of 1:1, the diisocyanate is hexamethylene diisocyanate, the chain extender is 1,4-butanediol, the catalyst is stannous octoate, the silane coupling agent is vinyl trimethoxysilane, the toughening agent is 2-pyrrolidine methyl acetate, and the solvent is composed of N-methyl pyrrolidone and ethyl acetate in a weight ratio of 1:1.

[0046] The heat-conducting filler is made by the following steps:

[0047] (1) Add magnesium oxide and hafnium tetrachloride to deionized water and stir for 20 minutes to obtain a mixed solution. The weight ratio of magnesium oxide, hafnium tetrachloride and deionized water is 2:1:10. Adjust the pH value to 9 with ammonia water with a concentration of 1 mol / L, and stir for 10 minutes to obtain a suspension. The suspension is filtered to obtain a precipitate. The precipitate is washed with deionized water for 3 times, and then placed in an autoclave. Heat to 350°C at a temperature rising rate of 5°C / min, and then keep the temperature for 5 hours. Naturally cool to room temperature to obtain solid material one. Grind the solid material one and pass it through a 200-mesh sieve to obtain a composite powder;

[0048] (2) The carbon black, anhydrous ethanol, silicon carbide ball and the composite powder obtained in step (1) in a weight ratio of 1:6:5:2 were added into a planetary ball mill, and the slurry was obtained by ball milling for 2 hours. The slurry was dried at 80℃ for 24 hours to obtain a ball-milled powder. The ball-milled powder was placed in a tube furnace, and the temperature was raised to 1400℃ at a rate of 10℃ / min under an argon atmosphere, and then the temperature was kept for 2 hours. The furnace was cooled to room temperature to obtain solid material two. The solid material two was ground and passed through a 200-mesh sieve to obtain the heat-conducting filler.

[0049] The preparation method of Example 3 comprises the following steps:

[0050] S1. The components were weighed by weight parts. The polyol was placed in a reaction bottle with a vacuum degree of 0.09 MPa, heated to 110℃, vacuum dehydrated for 1 hour, and then cooled to 80℃;

[0051] S2. The diisocyanate was added to the reaction bottle, and stirred at a speed of 200 revolutions per minute for 2 hours, and then cooled to 70℃;

[0052] S3. The other components were added to the reaction bottle, and stirred at a speed of 200 revolutions per minute for 1 hour to obtain the heat-conducting adhesive composition.

[0053] Example 4

[0054] The heat-conducting adhesive composition was made of the following components by weight parts: polyol 57 parts, diisocyanate 46 parts, chain extender 7 parts, catalyst 0.7 parts, heat-conducting filler 55 parts, silane coupling agent 1.6 parts, toughening agent 5 parts, and solvent 21 parts. The polyol was composed of castor oil polyol and polytetrahydrofuran diol in a weight ratio of 1:1, the diisocyanate was hexamethylene diisocyanate, the chain extender was 1,4-butanediol, the catalyst was stannous octoate, the silane coupling agent was vinyl trimethoxysilane, the toughening agent was 2-pyrrolidine methyl acetate, and the solvent was composed of N-methyl pyrrolidone and ethyl acetate in a weight ratio of 1:1.

[0055] The heat-conducting filler was made by the following steps:

[0056] (1) Magnesium oxide and hafnium tetrachloride were added to deionized water and stirred for 28 minutes to obtain a mixed solution. The weight ratio of magnesium oxide, hafnium tetrachloride and deionized water was 2:1:10. After adjusting the pH value to 9 with ammonia water with a concentration of 1 mol / L, the suspension was obtained by stirring for 18 minutes. The precipitate was obtained by suction filtration, and then washed with deionized water for 3 times. The precipitate was placed in an autoclave and heated to 350℃ at a rate of 5℃ / min, and then kept for 6.5 hours. The solid material one was obtained by natural cooling to room temperature. The solid material one was ground and passed through a 200-mesh sieve to obtain the composite powder;

[0057] (2) The carbon black, anhydrous ethanol, silicon carbide ball and the composite powder obtained in step (1) in a weight ratio of 1:6:5:2 were added into a planetary ball mill, and the slurry was obtained by ball milling for 2.5 hours. The slurry was dried at 80°C for 24 hours to obtain a ball-milled powder. The ball-milled powder was placed in a tube furnace, and the temperature was raised to 1400°C at a rate of 10°C / min under an argon atmosphere, and then the temperature was kept for 3 hours. The furnace was cooled to room temperature to obtain a solid product II. The solid product II was ground and passed through a 200-mesh sieve to obtain the heat-conducting filler.

[0058] The preparation method of Example 4 comprises the following steps:

[0059] S1. The components were weighed by weight parts. The polyol was placed in a reaction bottle with a vacuum degree of 0.09 MPa, heated to 108°C, and vacuum dehydrated for 1.2 hours, and then cooled to 78°C;

[0060] S2. The diisocyanate was added to the reaction bottle, and stirred at a speed of 300 rpm for 2 hours, and then cooled to 66°C;

[0061] S3. The other components were added to the reaction bottle, and stirred at a speed of 300 rpm for 2 hours to obtain the heat-conducting adhesive composition.

[0062] Comparative Example 1

[0063] Different from Example 1: the heat-conducting filler was not included in the components, and the preparation step of the heat-conducting filler was omitted.

[0064] Comparative Example 2

[0065] Different from Example 1: the heat-conducting filler in the components was replaced by magnesium carbide, and the preparation step of the heat-conducting filler was omitted.

[0066] Comparative Example 3

[0067] Different from Example 1: the toughening agent 2-pyrrolidine methyl acetate was not included in the components.

[0068] Experimental Example 1: Heat-conducting Property Test

[0069] The heat-conducting adhesive compositions obtained in Examples 1-4 and Comparative Examples 1-3 were respectively coated on the surface of a polytetrafluoroethylene plate, and then placed in an oven at 60°C for 24 hours to form an adhesive film with a thickness of 10 mm. The heat-conducting coefficients of the adhesive films of Examples 1-4 and Comparative Examples 1-2 were determined according to the heat-conducting standard test method ISO-22007-2.

[0070] The higher the heat-conducting coefficient, the better the heat-conducting property. The test results are shown in Table 1:

[0071]

[0072] Table 1

[0073] As can be seen from Table 1, the thermal conductivities of the heat-conducting adhesive compositions prepared in Examples 1-4 are all high, indicating that the heat-conducting adhesive compositions prepared in the application have good heat-conducting performance. The components and preparation steps used in Comparative Examples 1 and 2 are different from those in Example 1. Compared with Example 1, the thermal conductivity of Comparative Example 1 is significantly reduced, indicating that the heat-conducting filler prepared in the application can effectively improve the heat-conducting performance of the heat-conducting adhesive composition. Compared with Example 1, the thermal conductivity of Comparative Example 2 is slightly reduced, indicating that the heat-conducting filler prepared in the application has a better effect on improving the heat-conducting performance of the heat-conducting adhesive composition than magnesium carbide.

[0074] Experimental Example Two: Heat Resistance Test

[0075] The initial thermal decomposition temperatures of the adhesive films (prepared in Experimental Example One) of Examples 1-4 and Comparative Examples 1-3 were determined using a differential scanning calorimeter. The higher the initial thermal decomposition temperature, the better the heat resistance. The test results are shown in Table 2:

[0076]

[0077] Table 2

[0078] As can be seen from Table 2, the initial thermal decomposition temperatures of Examples 1-4 are all high, indicating that the heat-conducting adhesive compositions prepared in the application have good heat resistance. The components and preparation steps used in Comparative Examples 1-3 are different from those in Example 1. Compared with Example 1, the initial thermal decomposition temperatures of Comparative Examples 1 and 3 are both reduced, indicating that both the heat-conducting filler and the toughening agent 2-pyrrolidine methyl acetate used in the application can effectively improve the heat resistance of the heat-conducting adhesive composition. Compared with Example 1, the initial thermal decomposition temperature of Comparative Example 2 is slightly reduced, indicating that the heat-conducting filler prepared in the application has a better effect on improving the heat resistance of the heat-conducting adhesive composition than magnesium carbide.

[0079] Experimental Example Three: Impact Resistance Test

[0080] The impact strengths of the adhesive films (prepared in Experimental Example One) of Examples 1-4 and Comparative Examples 2-3 were determined according to the GB / T 6328-2021 standard. The higher the impact strength, the better the impact resistance. The test results are shown in Table 3:

[0081]

[0082] Table 3

[0083] As shown in Table 3, the impact strength of the heat-conducting adhesive compositions prepared in Examples 1-4 is high, indicating that the heat-conducting adhesive compositions prepared in the application have good impact resistance. The impact strength of Comparative Examples 2 and 3 is lower than that of Example 1, indicating that the hafnium carbide in the filler and the toughening agent 2-pyrrolidine methyl acetate used in the application can effectively improve the impact resistance of the heat-conducting adhesive composition.

[0084] The above examples are only illustrative of the principles and effects of the application, and are not intended to limit the application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the application should be covered by the claims of the application.

Claims

1. A thermally conductive adhesive composition, characterized in that: It is made from the following components in parts by weight: 56-60 parts of polyol, 45-48 parts of diisocyanate, 6-9 parts of chain extender, 0.4-0.8 parts of catalyst, 52-56 parts of thermally conductive filler, 1-2 parts of silane coupling agent, 4-7 parts of toughening agent, and 20-24 parts of solvent. The thermally conductive filler is prepared by the following steps: (1) Add magnesium oxide and hafnium tetrachloride to deionized water and stir for 20-30 minutes to obtain a mixed solution. Adjust the pH value to 9 with ammonia water and stir for 10-20 minutes to obtain a suspension. Filter the suspension to obtain a precipitate. Wash the precipitate three times with deionized water and place it in a hydrothermal reactor. Heat it to 350℃ and keep it at that temperature for 5-7 hours. After naturally cooling to room temperature, obtain solid one. Grind solid one and pass it through a 200-mesh sieve to obtain composite powder. (2) Add carbon black, anhydrous ethanol, grinding balls, and the composite powder obtained in step (1) into a planetary ball mill and ball mill for 2-3 hours to obtain a slurry. After drying the slurry, ball mill powder is obtained. The ball mill powder is placed in a tube furnace and heated to 1400℃ under an argon atmosphere and kept at that temperature for 2-3 hours. After cooling to room temperature with the furnace, solid material II is obtained. Solid material II is ground and passed through a 200-mesh sieve to obtain a thermally conductive filler.

2. The thermally conductive adhesive composition according to claim 1, characterized in that: The polyol is composed of castor oil polyol and polytetrahydrofuran diol in a weight ratio of 1:

1.

3. The thermally conductive adhesive composition according to claim 1, characterized in that: The diisocyanate is hexamethylene diisocyanate.

4. The thermally conductive adhesive composition according to claim 1, characterized in that: The chain extender is 1,4-butanediol.

5. The thermally conductive adhesive composition according to claim 1, characterized in that: The catalyst is stannous octoate.

6. The thermally conductive adhesive composition according to claim 1, characterized in that: In step (1) of the preparation of the thermally conductive filler, the weight ratio of magnesium oxide, hafnium tetrachloride and deionized water is 2:1:10, the concentration of ammonia water is 1 mol / L, and the heating rate of the hydrothermal reactor is 5℃ / min; in step (2), the grinding ball is a silicon carbide grinding ball, and the weight ratio of carbon black, anhydrous ethanol, grinding ball and composite powder obtained in step (1) is 1:6:5:2, the drying temperature is 80℃, the drying time is 24 hours, and the heating rate of the tube furnace is 10℃ / min.

7. The thermally conductive adhesive composition according to claim 1, characterized in that: The silane coupling agent is vinyltrimethoxysilane.

8. The thermally conductive adhesive composition according to claim 1, characterized in that: The toughening agent is methyl 2-pyrrolidone acetate, and the solvent consists of N-methylpyrrolidone and ethyl acetate in a weight ratio of 1:

1.

9. A method for preparing a thermally conductive adhesive composition according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Weigh each component according to the weight parts, place the polyol in a reaction flask with a vacuum degree of 0.09MPa, heat to 100-110℃ to remove water under vacuum for 1-2 hours, and then cool down to 70-80℃; S2. Add diisocyanate to the reaction flask, stir at 200-300 rpm for 2-3 hours, and then cool to 60-70℃; S3. Add the other components to the reaction flask and stir at 200-300 rpm for 1-2 hours to obtain the thermally conductive adhesive composition.

Images