Epoxy phase change materials, and compositions and methods thereof

Abstract

The invention relates to an epoxy type phase change material and a method for manufacturing the epoxy type phase change material. The epoxy-type phase change material includes a reaction product of an epoxy resin, an organic compound having two or more terminal hydroxyl groups, and a coupling agent. The epoxy equivalent weight (EEW) of the epoxy type phase change material is in a range of 300 to 400. The epoxy-type phase change material improves the performance, safety of electronic components, and has the ability to reduce and even eliminate the likelihood of thermal runaway or propagation in electronic devices. The present disclosure also relates to an epoxy phase change composition comprising an epoxy phase change material, a solvent, and a filler.

Description

Field of the Invention

[0001] The present disclosure relates to an epoxy type material. Specifically, the present disclosure relates to an epoxy type phase change material. More specifically, the present disclosure relates to an epoxy resin modified with an organic compound having two or more terminal hydroxyl groups. In addition, the present disclosure relates to a method for manufacturing an epoxy type phase change material. The present disclosure also relates to an epoxy type phase change composition comprising an epoxy type phase change material, a solvent and a filler.

[0002] Background and Prior Art

[0003] Phase change materials (PCMs) are substances that release or absorb enough energy to provide useful heating / cooling when they change phase. When a substance changes phase, thermal energy (called latent heat) is absorbed and released. Many materials have the ability to absorb large amounts of thermal energy during phase changes. Different materials melt and solidify at different temperatures, and they can absorb different amounts of thermal energy. PCMs can be used to control temperature in a wide range of applications because they melt and solidify at precise specified temperatures. Among various applications, PCMs are also widely used in automotive applications. PCMs are being studied in relation to potting applications.

[0004] Thermal energy can be stored in materials as sensible heat, latent heat, and thermochemical energy, among others, and can be a combination of more than one. Latent heat storage is considered to be the most convenient and efficient method for this purpose. PCMs have the further advantages of high heat storage capacity, thermal stability, and easily controllable phase change processes. Due to the increased interest in these materials and the understanding of their potential, a large number of organic, inorganic, polymeric, and eutectic PCMs have been designed.

[0005] Patent document US 7,488,773 B2 discloses a silicone rubber material containing finely divided phase change materials such as crystalline alkyl hydrocarbons or salt hydrates. The phase change material provides a thermal regulation system that greatly enhances the thermal properties of the silicone rubber material.

[0006] Patent document US005755987A describes a phase change material comprising a dibasic ester. Patent document WO2021035649A1 discloses a resin-type phase change energy storage material comprising a resin, a phase change powder and a curing agent.

[0007] Patent document CN107541027B discloses a phase change energy storage material prepared from a polymer matrix material, a phase change material, a porous filler and a thermal conductive filler. The phase change material used is paraffin. It should be noted that paraffin as a phase change material has low temperature stability or a lower operating temperature.

[0008] Patent document CA2720844A1 discloses a curable epoxy composition comprising an epoxy resin, a hardener and an endothermic transition additive (PCM). The disclosed endothermic transition additive (PCM) is, for example, an organic polymer, including a thermoplastic material, or an inorganic material, including sodium thiosulfate pentahydrate, sodium acetate trihydrate, sodium sulfate decahydrate, hydrated barium hydroxide, nickel nitrate tetrahydrate, zinc nitrate hexahydrate, blends thereof, alloys thereof and eutectic mixtures thereof.

[0009] However, it is still desirable to obtain phase change materials that can improve the performance and safety of electronic components and have the ability to reduce and even eliminate the possibility of thermal runaway or propagation in electronic devices. It is still desirable to obtain phase change materials suitable for a wide range of applications. The present disclosure solves the above problems by providing epoxy-type phase change materials, compositions and preparation methods thereof.

[0010] Therefore, the present disclosure provides an epoxy-based phase change material and a method for preparing the same. The present disclosure also relates to an epoxy-based phase change composition comprising the epoxy-based phase change material. The present disclosure also provides products based on epoxy-based phase change materials exhibiting a phase change temperature of 40-55°C. SUMMARY OF THE INVENTION

[0012] The present disclosure relates to a solid to semi-solid (and reverse) epoxy-type phase change material, which comprises a reaction product of an epoxy resin, an organic compound having two or more terminal hydroxyl groups, and a coupling agent, wherein the epoxy-type phase change material is represented by the following formula (1):

[0013]

[0014] wherein 'A' represents the main chain of the epoxy resin, 'B' represents the main chain of the organic compound, and 'n' represents an integer having a value of 1 to 12. The epoxy equivalent weight (EEW) of the epoxy-type phase change material is in the range of 300-400.

[0015] The epoxy-based phase change material improves the performance, safety of electronic components, and has the ability to reduce and even eliminate the possibility of thermal runaway or propagation in electronic devices. In addition, the present disclosure relates to a method of making an epoxy-based phase change material.

[0016] The present disclosure also relates to an epoxy-type phase change composition comprising an epoxy-type phase change material. The epoxy-type phase change composition is prepared by mixing the epoxy-type phase change material, a solvent and a filler.

[0017] Details

[0018] Although the present invention is capable of various modifications and alternative forms, its specific aspects have been shown by way of example and will be described in detail below. However, it should be understood that it is not intended to limit the present invention to the specific forms disclosed, but on the contrary, the present invention should cover all modifications, equivalents and substitutes falling within the scope of the present invention.

[0019] Applicants intend to point out that the embodiments mentioned show only those specific details relevant to an understanding of aspects of the invention so as not to obscure the present disclosure with details that would be apparent to one of ordinary skill in the art having the benefit of the description herein.

[0020] The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive "comprising," such that a composition or method comprising a list of components includes not only those components, but may also include other components not expressly listed or inherent to such a method. In other words, one or more elements in a composition, system, or method preceded by "comprising..." does not, without more limitations, preclude the presence of other or additional elements in the system or method.

[0021] Therefore, one aspect of the present disclosure relates to an epoxy-based phase change material comprising a reaction product of the following components:

[0022] - Epoxy resin;

[0023] - organic compounds having two or more terminal hydroxyl groups;

[0024] - coupling agent;

[0025] The epoxy phase change material is represented by the following formula (1):

[0026]

[0027] wherein 'A' represents the main chain of the epoxy resin, wherein 'B' represents the main chain of an organic compound having two or more terminal hydroxyl groups, and wherein 'n' represents an integer having a value of 1 to 12, and

[0028] The organic compound is an aromatic organic compound having two or more terminal hydroxyl groups or a combination of aromatic and non-aromatic organic compounds having two or more terminal hydroxyl groups.

[0029] In one embodiment, the ratio of epoxy resin to organic compound is in the range of 7:1-10:1.5, preferably in the range of 7.5:1.1-8.5:1.2.

[0030] In one embodiment, the epoxy equivalent weight (EEW) of the epoxy-type phase change material is in the range of 300-400.

[0031] In yet another aspect of the present disclosure, EEW is measured by a titration method involving the following steps:

[0032] (i) Weigh 0.3 to 0.4 g of sample in a conical flask.

[0033] (ii) In step 1, add 10 mL of 1,4-dioxane and 10 mL of chlorobenzene to the conical flask and stir until the sample is completely dissolved.

[0034] (iii) Add 10 ml of TEAB solution in step 2 and stir.

[0035] (iv) Add 2-3 drops of crystal violet indicator in step 3 and stir well.

[0036] (v) The resulting solution was titrated with 0.1 N standard perchloric acid solution.

[0037] (vi) End point: Crystal violet turns green.

[0038] EEW calculation formula = sample weight × 1000 / burette reading × HClO4 equivalent concentration g / eq

[0039] In one embodiment, the phase transition temperature is between 40 and 55°C.

[0040] In yet another aspect of the present disclosure, the phase transition temperature is measured by the following method.

[0041] The PCM material was placed in a petri dish and gradually heated in an oven at a temperature ranging from 25°C to 60°C, and the temperature at which the phase transition occurred was recorded.

[0042] The PCM temperature can also be measured by placing the PCM material in a flask equipped with a thermometer, then gradually heating it, and then recording the temperature at which the phase change occurs.

[0043] Epoxy oligomers or polymers suitable for use in the compositions of the present disclosure include those derived from bisphenol-A, hydrogenated bisphenol-A, bisphenol-F, bisphenol-S, novolac epoxies, phenol novolac epoxies, cresol novolac epoxies, N-glycidyl epoxies, glyoxal epoxies, dicyclopentadiene phenolic epoxies, silicone-modified epoxies, and epsilon-caprolactone modified epoxies. Combinations of different halogenated epoxy oligomers may also be used.

[0044] In a preferred embodiment, the main chain 'A' of the epoxy resin is selected from bisphenol-A based epoxy resins, such as bisphenol A diglycidyl ether (DGEBA or BADGE), or bisphenol-F based epoxy resin (BPF).

[0045] Epoxy resins based on bisphenol A and epoxy resins based on bisphenol F are commercially available, such as EPIKOTE 828, EPOTECYD 128, and EPIKOTE 862.

[0046] In one embodiment, the backbone 'A' of the epoxy resin is preferably selected from but not limited to halogenated bisphenol A type resin or bisphenol F type resin, or a mixture thereof.

[0047] In a preferred embodiment, the aromatic organic compound having two or more terminal hydroxyl groups is selected from hydroquinone, resorcinol, catechol or a mixture thereof.

[0048] In another preferred embodiment, the non-aromatic organic compound having two or more terminal hydroxyl groups is selected from 1,6-hexanediol, 1,4-butanediol or a mixture thereof.

[0049] In yet another embodiment of the present disclosure, the coupling agent may be used as known in the art and is not limited, but is preferably selected from triphenylphosphonium acetate or triphenylphosphine or a mixture thereof.

[0050] In yet another embodiment of the present disclosure, the amount of the epoxy resin is selected from the range of 50-99 wt %, preferably from the range of 70-90 wt %.

[0051] In yet another embodiment of the present disclosure, the amount of the organic compound having two or more terminal hydroxyl groups is selected from the range of 1-50 wt %, preferably from the range of 10-30 wt %.

[0052] In yet another embodiment of the present disclosure, the amount of the coupling agent is selected from 0.005-3 wt%, preferably 0.01-0.1 wt%.

[0053] Another aspect of the present disclosure relates to a method for preparing an epoxy-based phase change material, comprising the following steps:

[0054] a. Add epoxy resin, organic compound having two or more terminal hydroxyl groups and coupling agent into a container, and then stir.

[0055] b. raising the temperature from room temperature to a minimum of 70°C, preferably between 70°C and 140°C, and maintaining the temperature for 2 to 5 hours to provide an epoxy-type phase change material,

[0056] The epoxy phase change material is represented by the following formula (1):

[0057]

[0058] wherein 'A' represents the main chain of the epoxy resin, wherein 'B' represents the main chain of an organic compound having two or more terminal hydroxyl groups, and wherein 'n' represents an integer having a value of 1 to 12, and

[0059] The organic compound is an aromatic organic compound having two or more terminal hydroxyl groups or a combination of aromatic and non-aromatic organic compounds having two or more terminal hydroxyl groups.

[0060] Yet another aspect of the present disclosure relates to an epoxy-type phase change composition, which includes an epoxy-type phase change material, a solvent, and a filler.

[0061] In one embodiment of the present disclosure, the epoxy type phase change composition is prepared by mixing an epoxy type phase change material, a solvent, and a filler.

[0062] In another embodiment of the present disclosure, the amount of the epoxy type phase change material is in the range of 20-70 wt %.

[0063] In yet another embodiment of the present disclosure, the filler is selected from, but not limited to, aluminum trihydrate (ATH), alumina, boron nitride, aluminum nitride, zinc oxide, or a combination thereof.

[0064] In yet another embodiment of the present disclosure, the amount of the filler is selected from the range of 10-90 wt %, preferably from the range of 30-70 wt %.

[0065] In one embodiment of the present disclosure, the solvent is selected from, but not limited to, propylene carbonate, 1,6-hexanediol glycidyl ether, phenyl glycidyl ether, or a mixture thereof.

[0066] In yet another embodiment of the present disclosure, the amount of solvent is selected from 5-20 wt%.

[0067] In another embodiment of the present disclosure, the thermally conductive phase change material has a latent heat capacity at 40° C. in the range of 17580 to 18500 KJ / kg by DSC analysis.

[0068] In yet another embodiment of the present disclosure, the epoxy-type phase change material is used in insulated gate bipolar transistor (IGBT) gel applications, energy storage devices, and electric vehicle potting applications.

[0069] Another aspect of the present disclosure relates to products based on epoxy-type phase change materials that exhibit a phase change temperature of -40-55°C and an improved thermal conductivity (TC) of -15-25%.

[0070] Further salient features providing the disclosed enhanced epoxy-based phase change materials and methods of making the same are discussed in the examples provided below. Example

[0071] Preparation of epoxy phase change material (PCM):

[0072] PCM 1: Standard epoxy resin DGEBA (89.58 parts by weight in wt%), resorcinol (10.39 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was increased from room temperature to 70°C for 30 minutes, then 80°C for 30 minutes, 100°C for another 30 minutes, 120°C for 1 hour, then 130-140°C for 90 minutes. The reaction mixture was cooled and the product was obtained as a dark brown solid.

[0073] The epoxy equivalent weight (EEW) of this PCM is 330-350.

[0074] PCM 2: Standard epoxy resin DGEBA (89.58 parts by weight in wt%), catechol (10.39 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was raised from room temperature to 70°C for 30 minutes, then 80°C for 30 minutes, 100°C for another 30 minutes, 120°C for 1 hour, then 130-140°C for 90 minutes. The reaction mixture was cooled and the product was obtained as a dark brown solid.

[0075] The epoxy equivalent weight (EEW) of this PCM is 320-350.

[0076] PCM based on bisphenol F epoxy resin

[0077] PCM 3: Bisphenol F epoxy resin (89.58 parts by weight in wt%), hydroquinone (10.39 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was raised from room temperature to 70°C for 30 minutes, then 80°C for 30 minutes, 100°C for another 30 minutes, 120°C for 1 hour, then 130-140°C for 90 minutes. The reaction mixture was cooled and the product was obtained as a dark brown solid.

[0078] The epoxy equivalent weight (EEW) of the PCM is 300-350.

[0079] PCM 4: Bisphenol F epoxy resin (89.58 parts by weight in wt%), resorcinol (10.39 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was raised from room temperature to 70°C for 30 minutes, then 80°C for 30 minutes, 100°C for another 30 minutes, 120°C for 1 hour, then 130-140°C for 90 minutes. The reaction mixture was cooled and the product was obtained as a dark brown solid.

[0080] The epoxy equivalent weight (EEW) of this PCM is 310-350.

[0081] PCM 5: Bisphenol F epoxy resin (89.58 parts by weight in wt%), catechol (10.39 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was raised from room temperature to 70°C for 30 minutes, then 80°C for 30-40 minutes, 100°C for another 30 minutes, 120°C for 1 hour, then 130-140°C for 2 hours. The reaction mixture was cooled and the product was obtained as a dark brown solid.

[0082] The epoxy equivalent weight (EEW) of this PCM is 320-350.

[0083] PCM based on bisphenol A liquid epoxy resin (DGEBA)

[0084] PCM 6: Standard epoxy resin DGEBA (87.29 parts by weight in wt%), hydroquinone (11.19 parts by weight in wt%), 1,6-hexanediol (1.46 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.06 parts by weight in wt%) were charged into a clean and dry kettle and stirred. The reaction temperature was increased from room temperature to 220°C and maintained for 4 hours. The reaction mixture was cooled and a product with a dark brown solid was obtained.

[0085] The epoxy equivalent weight (EEW) of this PCM is 360-380.

[0086] PCM 7: Standard epoxy resin DGEBA (87.29 parts by weight in wt%), resorcinol (11.20 parts by weight in wt%), 1,6-hexanediol (1.46 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean and dry kettle and stirred. The reaction temperature was increased from room temperature to 220°C and maintained for 4 hours. The reaction mixture was cooled and a product with a dark brown solid was obtained.

[0087] The epoxy equivalent weight (EEW) of this PCM is 370-390.

[0088] PCM 8: Standard epoxy resin DGEBA (YD 128) (87.30 parts by weight in wt%), catechol (11.19 parts by weight in wt%), 1,6-hexanediol (1.46 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.03 parts by weight in wt%) were charged into a clean and dry kettle and stirred. The reaction temperature was increased from room temperature to 220°C and maintained for 4 hours, and finally at 250°C for 1 hour. The reaction mixture was cooled and a product with a dark brown solid was obtained.

[0089] The epoxy equivalent weight (EEW) of this PCM is 355-380.

[0090] Control 1 (Comparative Example)

[0091] Control 1: Standard epoxy resin DGEBA (85.14 parts by weight in wt%), 1,6-hexanediol (14.81 parts by weight in wt%) and ethyl triphenylphosphonium acetate (0.05 parts by weight in wt%) were charged into a clean, dry kettle and stirred. The reaction temperature was raised from room temperature to 220°C and maintained for 4 hours. The reaction mixture was cooled. The reaction mixture was cooled and a product having a dark brown solid was obtained.

[0092] The epoxy equivalent weight (EEW) of Control 1 was 360-375.

[0093]

[0094] The above embodiment is reproduced in the following Table 1:

[0095] Preparation of epoxy phase change composition:

[0096] The epoxy phase change composition is prepared by mixing an epoxy phase change material (PCM) with a filler and a solvent in a container. The amount of the epoxy phase change material is in the range of 20-70 wt %, and the amount of the corresponding filler is in the range of 30-80 wt %. The fillers used in the embodiments of the present disclosure are aluminum oxide / alumina and boron nitride. The solvent used in the embodiments of the present disclosure is propylene carbonate.

[0097] The PCM temperatures of the examples (Examples 1-9 and Comparative Example 1) prepared by the above method were analyzed. The results are shown in Table 2 below:

[0098] Table 1: Epoxy Phase Change Materials (PCM)

[0099]

[0100] Table 2: Embodiments according to the present disclosure

[0101]

[0102] As is apparent from Table 2, the epoxy-type phase change composition comprising the epoxy-type phase change material (PCM) according to the present disclosure yields a phase change temperature of -40-55°C.

[0103] As described above, according to the epoxy-type phase change material (PCM) of the present disclosure, it is possible to improve the performance of electronic components, ensure safety, and reduce and even eliminate the possibility of thermal runaway or propagation in electronic devices.

[0104] The advantages of the disclosed invention are thus achieved in an economical, practical and simple manner. Although preferred embodiments and examples have been shown and described, it is to be understood that various further modifications and additional configurations are apparent to those skilled in the art. The specific embodiments disclosed herein are intended to illustrate preferred and best modes for practicing the invention and should not be construed as limiting the scope of the invention.

Claims

1. An epoxy phase change material comprising the reaction product of the following components: - Epoxy resin; - organic compounds having two or more terminal hydroxyl groups; - coupling agent; The epoxy phase change material is represented by the following formula (1): Wherein 'A' represents the main chain of the epoxy resin, Where 'B' represents the main chain of the organic compound, where 'n' represents an integer value from 1 to 12, and wherein the organic compound is an aromatic organic compound having two or more terminal hydroxyl groups or a combination of aromatic and non-aromatic organic compounds having two or more terminal hydroxyl groups; The epoxy equivalent weight (EEW) of the epoxy-type phase change material is in the range of 300-400.

2. The epoxy-type phase change material according to claim 1, wherein the ratio of epoxy resin to organic compound is in the range of 7:1-10:1.

5.

3. The epoxy type phase change material according to claim 1, wherein the phase change temperature is between 40 and 55°C.

4. The epoxy-type phase change material according to claim 1, wherein the aromatic organic compound having two or more terminal hydroxyl groups is selected from hydroquinone, resorcinol, catechol or a mixture thereof, and the non-aromatic organic compound having two or more terminal hydroxyl groups is selected from 1,6-hexanediol, 1,4-butanediol or a mixture thereof. 5 . The epoxy phase change material according to claim 1 , wherein the epoxy resin is selected from bisphenol A epoxy resin, bisphenol F epoxy resin or a mixture thereof.

6. The epoxy phase change material according to claim 1, wherein the coupling agent is selected from ethyltriphenylphosphonium acetate or triphenylphosphine or a mixture thereof.

7. The epoxy type phase change material according to claim 1, wherein the amount of epoxy resin is in the range of 50-99 wt%, preferably 70-90 wt%.

8. The epoxy type phase change material according to claim 1, wherein the amount of the organic compound having two or more terminal hydroxyl groups is in the range of 1-50 wt%, preferably 10-30 wt%.

9. The epoxy type phase change material according to claim 1, wherein the amount of the coupling agent is in the range of 0.005-3 wt%, preferably 0.01-0.1 wt%.

10. A method for preparing the epoxy phase change material according to claims 1 to 9, comprising the following steps: a. Add epoxy resin, organic compound having two or more terminal hydroxyl groups and coupling agent into a container, and then stir. b. raising the temperature from room temperature to a minimum of 70°C, preferably between 70°C and 140°C, and maintaining the temperature for 2 to 5 hours to provide an epoxy-type phase change material, The epoxy phase change material is represented by the following formula (1): Wherein 'A' represents the main chain of the epoxy resin, wherein 'B' represents the main chain of an organic compound having two or more terminal hydroxyl groups, where 'n' represents an integer value from 1 to 12, and The organic compound is an aromatic organic compound having two or more terminal hydroxyl groups or a combination of aromatic and non-aromatic organic compounds having two or more terminal hydroxyl groups. 11 . An epoxy type phase change composition comprising the epoxy type phase change material according to claim 1 , a solvent and a filler.

12. The epoxy type phase change composition according to claim 11, wherein the epoxy type phase change material according to claims 1 to 9 is in the range of 20-70 wt%, the solvent is in the range of 5-20 wt%, and the filler is in the range of 10-90 wt%.

13. The epoxy-based phase change composition according to claim 11, wherein the filler is selected from aluminum trihydrate (ATH), aluminum oxide, boron nitride, aluminum nitride, zinc oxide, or a combination thereof.

14. The epoxy type phase change composition according to claim 11, wherein the solvent is selected from propylene carbonate or 1,6-hexanediol glycidyl ether or phenyl glycidyl ether or a mixture thereof.

15. The epoxy type phase change composition according to claim 11, used as and for insulated gate bipolar transistor (IGBT) gel applications, energy storage devices, and electric vehicle potting applications.

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