Castor oil-based hyperbranched heat-conducting toughening agent as well as preparation method and application thereof

Abstract

The invention relates to a castor oil-based hyperbranched heat-conducting toughening agent as well as a preparation method and application thereof, and relates to the field of polymer composite materials. The castor oil-based hyperbranched heat-conducting toughening agent is prepared from the following raw materials: castor oil-based hyperbranched polyol, hydroxylated heat-conducting particles and isocyanate, the preparation raw materials are subjected to addition polymerization reaction to obtain the castor oil-based hyperbranched heat-conducting toughening agent. The castor oil-based hyperbranched heat-conducting toughening agent is prepared on the basis of castor oil-based hyperbranched polyol from a bio-based source, replaces a traditional petroleum-based organic matter, not only meets the requirement of sustainable development, but also can realize synergistic optimization of toughening and heat conduction.

Description

Technical Field

[0001] The present invention relates to the field of polymer composite materials, in particular to a castor oil-based hyperbranched thermal conductive toughening agent and a preparation method and application thereof. Background Art

[0002] With the development of miniaturization and high power of electronic devices, the demand for composite materials with excellent thermal conductivity and mechanical toughening functions for advanced packaging materials is becoming increasingly urgent. Traditional epoxy resin-based packaging materials have defects such as high brittleness and low intrinsic thermal conductivity (usually <0.2W / (m·K)), which makes it difficult to meet the dual requirements of thermal management performance and structural reliability of new electronic devices such as 5G communication equipment and high-power LEDs. Existing technologies mainly introduce thermal conductive fillers (such as aluminum nitride, aluminum oxide, etc.) and toughening agents (such as rubber particles, core-shell structure polymers, etc.) through physical blending. However, this technical route has the following significant defects: (1) uneven dispersion of functional components, which easily leads to stress concentration points and causes a decrease in the impact strength of the material; (2) contradiction between the synergistic optimization of toughening and thermal conductivity; (3) demand for green polymer materials. Summary of the Invention

[0003] In response to the above problems, the present invention provides a castor oil-based hyperbranched thermal conductive toughening agent. The castor oil-based hyperbranched thermal conductive toughening agent is prepared based on bio-based castor oil-based hyperbranched polyols, replacing traditional petroleum-based organic matter. It not only meets the requirements of sustainable development, but also can achieve synergistic optimization of toughening and thermal conductivity.

[0004] The present invention provides a castor oil-based hyperbranched thermally conductive toughening agent. The raw materials for preparing the castor oil-based hyperbranched thermally conductive toughening agent include: castor oil-based hyperbranched polyol, hydroxylated thermally conductive particles and isocyanate; the castor oil-based hyperbranched thermally conductive toughening agent is obtained by an addition polymerization reaction of the raw materials;

[0005] The mass ratio of the castor oil-based hyperbranched polyol, the hydroxylated thermally conductive particles and the isocyanate is 1:(0.02-0.08):(0.3-0.6).

[0006] The inventor is in order to solve the problem that traditional petroleum-based toughening agent (such as CTBN, HTBN etc.) is not green and environmentally friendly, selects the castor oil-based hyperbranched polyol of bio-based source to prepare as basis, this castor oil-based hyperbranched polyol is the hyperbranched polyol structure of nine functionality, can play the effect of low viscosity, high crosslinking density, provide multiple energy dissipation matrix, promote toughening efficiency.Simultaneously, introduce hydroxylation heat-conducting particles, by isocyanate cross-linking castor oil-based hyperbranched polyol, hydroxylation heat-conducting particles, on the one hand solve the dispersion problem of heat-conducting particles, on the other hand the carbamate group that NCO and OH generate, and the hydroxyl group of castor oil polyol form intermolecular and intramolecular hydrogen bond effect, can reduce phonon scattering, form efficient heat-conducting network, thus reach only with castor oil-based hyperbranched polyol and hydroxylation heat-conducting ion coordination, the additive finally prepared can both heat conduction, can toughening.And traditional formula design then needs to add toughening agent, thermally conductive filler respectively, just can make additive have the dual effect of heat conduction, toughening.

[0007] In one embodiment, the preparation method of the castor oil-based hyperbranched thermal conductive toughening agent comprises: dispersing castor oil-based hyperbranched polyol and hydroxylated thermal conductive particles in a solvent, adding isocyanate dropwise at low temperature to react, and removing the solvent to obtain the castor oil-based hyperbranched thermal conductive toughening agent;

[0008] The castor oil-based hyperbranched polyol is prepared from castor oil and thioglycerol through a click reaction; the hydroxylated thermally conductive particles are obtained by modifying thermally conductive particles with alkali solution.

[0009] The above preparation method can successfully prepare castor oil-based hyperbranched thermal conductive toughening agents under low viscosity (hyperbranched structure design), conventional solvents, and low temperature conditions; the above click reaction uses green and renewable castor oil as a reaction substrate, fully utilizing the structural characteristics of castor oil's long carbon chain flexible structure, unsaturated double bonds, and natural hydroxyl groups to prepare a nine-functionality hyperbranched polyol structure, and the reaction selectivity is very high. The reaction only involves thiol groups and double bonds, with few side reactions and a high reaction rate.

[0010] In one embodiment, the isocyanate includes at least one of TDI, MDI, HDI, and IPDI.

[0011] The present invention also provides a method for preparing the castor oil-based hyperbranched thermal conductive toughening agent, comprising the following steps:

[0012] Dispersing castor oil-based hyperbranched polyol and hydroxylated thermally conductive particles in a solvent, adding isocyanate dropwise at low temperature to react, and removing the solvent to obtain a castor oil-based hyperbranched thermally conductive toughening agent;

[0013] The castor oil-based hyperbranched polyol is prepared from castor oil and thioglycerol through a click reaction; the hydroxylated thermally conductive particles are obtained by modifying thermally conductive particles with alkali solution.

[0014] In one embodiment, the solvent comprises at least one of dichloromethane, acetone, butanone, toluene, DMF, and DMAc, and the amount of the solvent is 20-40 wt % of the raw material.

[0015] In one embodiment, the method for preparing the castor oil-based hyperbranched polyol comprises: uniformly mixing castor oil and thioglycerol in an organic solvent, adding a free radical photoinitiator, irradiating with ultraviolet light for reaction, and removing the organic solvent by rotary evaporation to obtain the castor oil-based hyperbranched polyol;

[0016] The preparation method of the hydroxylated thermally conductive particles comprises: placing the thermally conductive particles in an alkaline solution, heating and stirring, and performing a hydroxylation reaction to obtain the hydroxylated thermally conductive particles.

[0017] In one embodiment, in the method for preparing the castor oil-based hyperbranched polyol, the molar ratio of castor oil to thioglycerol is 1:(2.7-3.0), the amount of the free radical photoinitiator is 3-5wt% of the raw material for preparing the castor oil-based hyperbranched polyol, and the ultraviolet light irradiation conditions include: irradiation under 1500-3000W ultraviolet light for 2-4h;

[0018] In the preparation method of the hydroxylated thermally conductive particles, the mass ratio of the thermally conductive particles to the alkali solution is 1:(10-35), the concentration of the alkali solution is 2-6 mol / L, the heating temperature is 60-90° C., and the hydroxylation reaction time is 6-18 h.

[0019] In one embodiment, the organic solvent comprises at least one of dichloromethane, acetone, butanone, toluene, and anhydrous ethanol;

[0020] The free radical photoinitiator includes at least one of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2,4,6-trimethylbenzoylphenyl ethylphosphonate;

[0021] The thermally conductive particles include at least one of diamond, boron nitride, aluminum nitride, aluminum oxide, and aluminum hydroxide;

[0022] The alkali solution includes an aqueous sodium hydroxide solution.

[0023] In one embodiment, the thermally conductive particles are spherical or quasi-spherical.

[0024] In one embodiment, the low temperature condition is 25-45° C., and the reaction time is 0.5-3 h.

[0025] The present invention also provides application of the castor oil-based hyperbranched thermal conductive toughening agent in composite materials.

[0026] The present invention also provides a composite material, the raw materials of which include the castor oil-based hyperbranched thermal conductive toughening agent.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention discloses a castor oil-based hyperbranched thermally conductive toughening agent, a preparation method thereof, and an application thereof. The castor oil-based hyperbranched thermally conductive toughening agent is prepared based on bio-based castor oil-based hyperbranched polyols, replacing traditional petroleum-based organic matter. It not only meets the requirements of sustainable development, but also can achieve synergistic optimization of toughening and thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the reaction process for preparing castor oil-based hyperbranched polyols. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] Unless otherwise specified, the reagents, materials, and equipment used in this example are all commercially available; and the experimental methods, unless otherwise specified, are all conventional experimental methods in the art.

[0033] In the present invention, the mass ratio of the castor oil-based hyperbranched polyol, the hydroxylated thermally conductive particles and the isocyanate is 1:(0.02-0.08):(0.3-0.6).

[0034] The hydroxylated thermally conductive particle modification method includes the following steps: placing 10g of thermally conductive particles in 100ml of a 5mol / L sodium hydroxide aqueous solution, stirring at 80°C, reacting for 8 hours, centrifuging, washing, and drying to obtain the hydroxylated thermally conductive particles. In this preparation method, the mass ratio of the thermally conductive particles to the sodium hydroxide aqueous solution is 1:11.9.

[0035] The method for preparing castor oil-based hyperbranched polyol comprises the following steps: uniformly mixing 0.1 mol (93.4 g) of castor oil, 0.27 mol (29.2 g) of thioglycerol, 30 g of dichloromethane, and 4 g of a free radical photoinitiator, 2-hydroxy-2-methyl-1-phenylacetone; then reacting the mixture under 1500 W ultraviolet light for 2 hours; and then removing the solvent to obtain castor oil-based hyperbranched polyol. The reaction process is as follows: Figure 1 As shown, in the above preparation method, the molar ratio of castor oil to thioglycerol is 1:2.7, and the mass of the free radical photoinitiator accounts for 3.26% of the total mass of castor oil and thioglycerol.

[0036] Example 1

[0037] A castor oil-based hyperbranched thermal conductive toughening agent, the preparation steps of which are as follows:

[0038] Step 1: Select boron nitride thermal conductive particles and modify them using the above method to obtain hydroxylated boron nitride thermal conductive particles;

[0039] Step 2: Disperse 10g of a castor oil-based hyperbranched polyol and 0.5g of hydroxylated boron nitride in 3ml of acetone. Then, add 6g of HDI dropwise. The mixture reacts at 45°C for 2h, and the solvent is removed to obtain a castor oil-based hyperbranched thermally conductive toughening agent. In this example, the mass ratio of castor oil-based hyperbranched polyol, hydroxylated boron nitride, and HDI is 1:0.05:0.6.

[0040] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0041] Table 1 Amount of each raw material used in Example 1 epoxy resin based composite material

[0042] Raw material ingredients Mass fraction epoxy resin 70 servings Castor oil-based hyperbranched thermal conductive toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0043] Example 2

[0044] A castor oil-based hyperbranched thermal conductive toughening agent, the preparation steps of which are as follows:

[0045] Step 1: Select diamond thermal conductive particles and modify them using the above method to obtain hydroxylated boron nitride thermal conductive particles;

[0046] Step 2: Disperse 10g of castor oil-based hyperbranched polyol and 0.5g of hydroxylated diamond in 3ml of acetone. Then, add 6g of HDI dropwise. The mixture reacts at 45°C for 2h, and the solvent is removed to obtain a castor oil-based hyperbranched thermally conductive toughening agent. In this example, the mass ratio of castor oil-based hyperbranched polyol, hydroxylated diamond, and HDI is 1:0.05:0.6.

[0047] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0048] Table 2 Amounts of raw materials used in Example 2 epoxy resin-based composite materials

[0049] Raw material ingredients Mass fraction epoxy resin 70 servings Castor oil-based hyperbranched thermal conductive toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0050] Example 3

[0051] A castor oil-based hyperbranched thermal conductive toughening agent, the preparation steps of which are as follows:

[0052] Step 1: Select alumina thermal conductive particles and modify them using the above method to obtain hydroxylated boron nitride thermal conductive particles;

[0053] Step 2: Disperse 10g of castor oil-based hyperbranched polyol and 0.5g of hydroxylated alumina in 3ml of acetone. Then, add 6g of HDI dropwise. The mixture reacts at 45°C for 2h, and the solvent is removed to obtain a castor oil-based hyperbranched thermally conductive toughening agent. In this example, the mass ratio of castor oil-based hyperbranched polyol, hydroxylated alumina, and HDI is 1:0.05:0.6.

[0054] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0055] Table 3 Amounts of raw materials used in Example 3

[0056]

[0057]

[0058] Example 4

[0059] A castor oil-based hyperbranched thermal conductive toughening agent, the preparation steps of which are as follows:

[0060] Step 1: Select aluminum hydroxide thermal conductive particles and modify them using the above method to obtain hydroxylated boron nitride thermal conductive particles;

[0061] Step 2: Disperse 10g of a castor oil-based hyperbranched polyol and 0.5g of hydroxylated aluminum hydroxide in 3ml of acetone. Then, add 6g of HDI dropwise. The mixture reacts at 45°C for 2h, and the solvent is removed to obtain a castor oil-based hyperbranched thermally conductive toughening agent. In this example, the mass ratio of castor oil-based hyperbranched polyol, hydroxylated aluminum hydroxide, and HDI is 1:0.05:0.6.

[0062] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0063] Table 4 Amounts of raw materials used in Example 4

[0064] Raw material ingredients Mass fraction epoxy resin 70 servings Castor oil-based hyperbranched thermal conductive toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0065] Example 5

[0066] A castor oil-based hyperbranched thermal conductive toughening agent, the preparation steps of which are as follows:

[0067] Step 1: Select aluminum nitride thermal conductive particles and modify them using the above method to obtain hydroxylated boron nitride thermal conductive particles;

[0068] Step 2: Disperse 10g of a castor oil-based hyperbranched polyol and 0.5g of hydroxylated aluminum nitride in 3ml of acetone. Then, add 6g of HDI dropwise. The mixture reacts at 45°C for 2h, and the solvent is removed to obtain a castor oil-based hyperbranched thermally conductive toughening agent. In this example, the mass ratio of castor oil-based hyperbranched polyol, hydroxylated aluminum nitride, and HDI is 1:0.05:0.6.

[0069] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0070] Table 5 Amounts of raw materials used in Example 5

[0071] Raw material ingredients Mass fraction epoxy resin 70 servings Castor oil-based hyperbranched thermal conductive toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0072] Comparative Example 1

[0073] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0074] Table 6 Amounts of raw materials used in Comparative Example 1

[0075] Raw material ingredients Mass fraction epoxy resin 70 servings CTBN toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0076] Comparative Example 2

[0077] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0078] Table 7 Amounts of raw materials used in Comparative Example 2

[0079] Raw material ingredients Mass fraction epoxy resin 70 servings HTBN toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0080] Comparative Example 3

[0081] The epoxy resin-based composite material is prepared according to the following formula. The preparation method of the epoxy resin-based composite material is: mixing raw materials, stirring, degassing, and curing to obtain the epoxy resin-based composite material.

[0082] Table 8 Amounts of raw materials used in Comparative Example 3

[0083] Raw material ingredients Mass fraction epoxy resin 70 servings CTPB toughening agent 20 servings curing agent 9 servings Accelerator 1 serving

[0084] Experimental example

[0085] Performance testing.

[0086] 1. Tensile strength: tested according to GB / T 7124 method.

[0087] 2. Impact toughness: tested according to GB / T 1043 method.

[0088] 3. Thermal conductivity test: Tested according to ASTM D5470 method.

[0089] 4. Insulation strength test: Chroma 19073 was used to test the insulation strength of the implementation case and the comparison case.

[0090] The performance test results of the samples of various embodiments and comparative examples are shown in Table 9 below.

[0091] Table 9 Sample performance test results

[0092]

[0093] As shown in Table 9, at the same addition amount, the castor oil-based hyperbranched thermally conductive toughening agent prepared in the present invention has a better toughening effect than the commonly used toughening agents in the field, such as carboxyl-terminated nitrile rubber (CTBN), hydroxyl-terminated nitrile rubber (HTBN), and carboxyl-terminated polybutadiene rubber (CTPB). Furthermore, traditional toughening agents lack the ability to dissipate heat, while the material prepared in the present invention has both toughening and thermal conductivity. This is because the hyperbranched molecular structure of castor oil can provide multiple energy dissipation mechanisms, improving toughening efficiency; at the same time, the addition of thermally conductive particles and intra- and intermolecular hydrogen bonds can reduce phonon scattering, establishing an efficient thermal conductive network, thereby making the resulting composite material have the dual functions of thermal conductivity and toughening.

[0094] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A castor oil-based hyperbranched thermally conductive toughening agent, characterized in that: The raw materials for preparing the castor oil-based hyperbranched thermal conductive toughening agent include: castor oil-based hyperbranched polyol, hydroxylated thermal conductive particles and isocyanate; the castor oil-based hyperbranched thermal conductive toughening agent is obtained by an addition polymerization reaction of the raw materials; The mass ratio of the castor oil-based hyperbranched polyol, the hydroxylated thermally conductive particles and the isocyanate is 1:(0.02-0.08):(0.3-0.6).

2. The castor oil-based hyperbranched thermally conductive toughening agent according to claim 1, wherein The preparation method of the castor oil-based hyperbranched thermal conductive toughening agent comprises: dispersing castor oil-based hyperbranched polyol and hydroxylated thermal conductive particles in a solvent, adding isocyanate dropwise at low temperature to react, and removing the solvent to obtain the castor oil-based hyperbranched thermal conductive toughening agent; The castor oil-based hyperbranched polyol is prepared from castor oil and thioglycerol through a click reaction; the hydroxylated thermally conductive particles are obtained by modifying thermally conductive particles with alkali solution.

3. The castor oil-based hyperbranched thermally conductive toughening agent according to any one of claims 1 to 2, characterized in that: The isocyanate includes at least one of TDI, MDI, HDI, and IPDI.

4. The method for preparing the castor oil-based hyperbranched thermally conductive toughening agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: Dispersing castor oil-based hyperbranched polyol and hydroxylated thermally conductive particles in a solvent, adding isocyanate dropwise at low temperature to react, and removing the solvent to obtain a castor oil-based hyperbranched thermally conductive toughening agent; The castor oil-based hyperbranched polyol is prepared from castor oil and thioglycerol through a click reaction; the hydroxylated thermally conductive particles are obtained by modifying thermally conductive particles with alkali solution.

5. The preparation method according to claim 4, characterized in that The preparation method of the castor oil-based hyperbranched polyol comprises: uniformly mixing castor oil and thioglycerol in an organic solvent, adding a free radical photoinitiator, irradiating with ultraviolet light for reaction, and removing the organic solvent by rotary evaporation to obtain the castor oil-based hyperbranched polyol; The preparation method of the hydroxylated thermally conductive particles comprises: placing the thermally conductive particles in an alkaline solution, heating and stirring, and performing a hydroxylation reaction to obtain the hydroxylated thermally conductive particles.

6. The preparation method according to claim 5, characterized in that In the method for preparing castor oil-based hyperbranched polyol, the molar ratio of castor oil to thioglycerol is 1:(2.7-3.0), the amount of the free radical photoinitiator is 3-5wt% of the raw material for preparing the castor oil-based hyperbranched polyol, and the ultraviolet light irradiation conditions include: irradiation under 1500-3000W ultraviolet light for 2-4 hours; In the preparation method of the hydroxylated thermally conductive particles, the mass ratio of the thermally conductive particles to the alkali solution is 1:(10-35), the concentration of the alkali solution is 2-6 mol / L, the heating temperature is 60-90° C., and the hydroxylation reaction time is 6-18 h.

7. The preparation method according to claim 5, characterized in that The organic solvent comprises at least one of dichloromethane, acetone, butanone, toluene and anhydrous ethanol; The free radical photoinitiator includes at least one of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2,4,6-trimethylbenzoylphenyl ethylphosphonate; The thermally conductive particles include at least one of diamond, boron nitride, aluminum nitride, aluminum oxide, and aluminum hydroxide; The alkali solution includes an aqueous sodium hydroxide solution.

8. The preparation method according to any one of claims 4 to 7, characterized in that The low temperature condition is 25-45° C., and the reaction time is 0.5-3 h.

9. Use of the castor oil-based hyperbranched thermally conductive toughening agent according to any one of claims 1 to 3 in a composite material.

10. A composite material, characterized in that The raw materials of the composite material include the castor oil-based hyperbranched thermal conductive toughening agent according to any one of claims 1 to 3.

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