UV insulating glue for improving insulating property of battery case and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, and discloses a UV insulation paste capable of improving the insulation performance of a battery case and a preparation method thereof.The UV insulation paste comprises, by weight, 100 parts of UV epoxy acrylate, 28-36 parts of an active diluent, 2.5-3.3 parts of a photoinitiator and the like; the reactive diluent is composed of an acrylate reactive diluent and di (acrylate benzoate butyl siloxane); the di (acrylate benzoate butyl siloxane) and UV epoxy acrylate are subjected to a photocuring reaction, siloxane with flexibility and electrical insulating property is grafted into the epoxy acrylate adhesive, the impact strength and the volume resistivity of the adhesive are improved, and meanwhile, the bonding performance of the adhesive and a PET base material is improved. Therefore, the adhesive can be better applied to bonding and insulation of a battery cell shell, and the electrical insulation and safety performance of the battery shell are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a UV insulating adhesive for improving the insulation performance of a battery shell and a preparation method thereof. Background Art

[0002] To improve the safety of new energy vehicle battery cells, the battery casing is typically coated with an insulating material to prevent short circuits caused by contact between the conductive metal casing and external components, ensuring electrical safety. This insulating material is primarily composed of PET polyester and PSA pressure-sensitive adhesive. Traditional PSA pressure-sensitive adhesives suffer from poor adhesion, prone to delamination, and poor insulation properties, hindering their practical application in high-voltage new energy vehicle batteries. Therefore, the development of new insulating adhesives is a research priority.

[0003] Epoxy resins offer high insulation, waterproofing, and strength, and are primarily used in insulating adhesives, structural adhesives, and anti-corrosion adhesives. Epoxy acrylates contain reactive olefin groups, allowing for rapid light-curing and easy construction. They are widely used in new energy vehicles, electronics, machinery, and construction. However, epoxy resins and UV-curing adhesives have poor toughness and are prone to cracking, severely impacting their bonding properties. Summary of the Invention

[0004] The present invention provides a UV insulating adhesive for improving the insulation performance of a battery shell and a preparation method thereof, which solves the problem of poor toughness of UV epoxy acrylate adhesives and simultaneously improves the bonding performance and insulation performance.

[0005] The technical solution of the present invention is: a UV insulating glue for improving the insulation performance of a battery shell and a preparation method thereof, wherein the UV insulating glue includes 100 parts by weight of UV epoxy acrylate, 28-36 parts by weight of an active diluent, 0.4-0.8 parts by weight of a defoaming agent, and 2.5-3.3 parts by weight of a photoinitiator; the active diluent is composed of 13-30 parts by weight of an acrylate active diluent and 6-15 parts by weight of di(acrylate benzoate butylsiloxane).

[0006] The preparation method of UV insulating glue comprises the following steps: adding UV epoxy acrylate, defoaming agent and active diluent into a container, adding photoinitiator after stirring, and packaging and storing in a light-proof manner to obtain UV insulating glue for improving the insulation performance of a battery shell.

[0007] Furthermore, the acrylate reactive diluent includes any one or a combination of tripropylene glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate.

[0008] Furthermore, the photoinitiator includes photoinitiator TPO and photoinitiator 184.

[0009] Further, the preparation method of di(acrylate benzoate butylsiloxane) comprises:

[0010] (1) Add a sodium hydroxide solution with a concentration of 1.6-2 mol / L and 4-hydroxybenzoic acid to a reaction vessel, stir, then add acryloyl chloride in an ice-water bath, stir for 40-60 minutes, then stir and react at 15-25° C. for 1-1.5 hours, dropwise add a 5-8% by mass hydrochloric acid solution to adjust the pH to 4-5, precipitate, filter, wash with water, and dry to obtain 4-acrylate benzoic acid.

[0011] (2) Dichloromethane, 4-acrylated benzoic acid, and 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane were added to a reaction vessel, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine were added in an ice-water bath. After stirring, the mixture was reacted at 20-35° C. for 12-18 hours, filtered, and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylated benzoate butylsiloxane).

[0012] Furthermore, the mass ratio of 4-hydroxybenzoic acid to acryloyl chloride in (1) is 100:(66-72).

[0013] Furthermore, the mass ratio of (2) 4-acrylated benzoic acid, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is (152-180):100:(190-208):(1-1.6).

[0014] The beneficial technical effect of the present invention is as follows: the present invention adds di(acrylate benzoate butyl siloxane) to the epoxy acrylate UV adhesive, which contains acrylate groups at both ends and can replace part of the tripropylene glycol diacrylate as a reactive diluent, and undergoes a photocuring reaction with the UV epoxy acrylate, thereby grafting the flexible and electrically insulating siloxane into the epoxy acrylate adhesive, significantly improving the impact strength and volume resistivity of the adhesive.

[0015] The di(acrylate benzoate butyl siloxane) of the present invention contains a benzoate structure similar to polyester PET, which improves the affinity and interface strength between the adhesive and the PET substrate, is conducive to improving the bonding performance with the PET substrate, has higher peel strength, and can be better applied to the bonding and insulation of battery core shells, thereby improving the electrical insulation and safety performance of the battery shell. DETAILED DESCRIPTION

[0016] The following describes specific embodiments of the present invention in detail. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0017] The following UV epoxy acrylate model is Haolong 2222, with an active ingredient content of 99%, and is sourced from Jiangsu Haolong Chemical Co., Ltd.

[0018] Example 1:

[0019] (1) Add 360 mL of 2 mol / L sodium hydroxide solution and 50 g of 4-hydroxybenzoic acid to a reaction vessel, stir, then add 33 g of acryloyl chloride in an ice-water bath, stir for 60 min, then stir and react at 25° C. for 1 h. Add 8% hydrochloric acid solution dropwise to adjust the pH to 4, precipitate, filter, wash with water, and dry to obtain 4-acrylate benzoic acid. The preparation reaction formula is:

[0020]

[0021] (2) 800 mL of dichloromethane, 72 g (375 mmol) of 4-acrylated benzoic acid, and 40 g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane were added to a reaction vessel. 76 g of dicyclohexylcarbodiimide and 0.4 g of 4-dimethylaminopyridine were added in an ice-water bath. The mixture was stirred and reacted at 35° C. for 12 h. The mixture was filtered and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylated benzoate butylsiloxane). The preparation reaction formula is:

[0022]

[0023] (3) Add 1 kg of UV epoxy acrylate, 5 g of defoamer Deqian DAPRO AP7072, 300 g of tripropylene glycol diacrylate, and 60 g of di(acrylate benzoate butyl siloxane) into a container, stir, add 27 g of photoinitiator TPO, and store in a dark place to obtain a UV insulating glue that improves the insulation performance of the battery shell.

[0024] Example 2:

[0025] (1) 400 mL of 1.6 mol / L sodium hydroxide solution and 50 g of 4-hydroxybenzoic acid were added to a reaction vessel, and after stirring, 36 g of acryloyl chloride was added in an ice-water bath and stirred for 40 min. The mixture was then stirred at 15° C. for 1.5 h. 8% hydrochloric acid solution was added dropwise to adjust the pH to 5. The precipitate was filtered, washed with water, and dried to obtain 4-acrylated benzoic acid.

[0026] (2) 700 mL of dichloromethane, 60.8 g of 4-acrylated benzoic acid, and 40 g (143.6 mmol) of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane were added to a reaction vessel, and 83.2 g of dicyclohexylcarbodiimide and 0.64 g of 4-dimethylaminopyridine were added in an ice-water bath. After stirring, the mixture was reacted at 20° C. for 18 h, filtered, and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylated benzoate butylsiloxane).

[0027] (3) Add 1 kg of UV epoxy acrylate, 8 g of defoamer Deqian DAPRO AP7072, 240 g of pentaerythritol triacrylate, and 90 g of di(acrylate benzoate butyl siloxane) into a container, stir, add 25 g of photoinitiator TPO, and store in a dark place to obtain a UV insulating glue that improves the insulation performance of the battery shell.

[0028] Example 3:

[0029] (1) 1 kg of UV epoxy acrylate, 5 g of defoamer Deqian DAPRO AP7072, 190 g of dipropylene glycol diacrylate, and 120 g of di(acrylate benzoate butyl siloxane) (prepared according to the method of Example 1) were added to a container, and after stirring, 33 g of photoinitiator 184 was added. The mixture was packaged and stored in a dark place to obtain a UV insulating adhesive that improves the insulation performance of the battery shell.

[0030] Example 4:

[0031] (1) 1 kg UV epoxy acrylate, 4 g defoamer Deqian DAPRO AP7072, 130 g trimethylolpropane triacrylate, and 150 g di(acrylate benzoate butyl siloxane) (prepared according to the method of Example 1) were added to a container, and after stirring, 26 g photoinitiator TPO was added. The mixture was packaged and stored in a dark place to obtain a UV insulating adhesive that improves the insulation performance of the battery shell.

[0032] Comparative Example 1: This comparative example differs from Example 1 in that tripropylene glycol diacrylate is used instead of di(acrylate benzoate butylsiloxane).

[0033] (1) Add 1 kg UV epoxy acrylate, 5 g defoamer Deqian DAPRO AP7072, and 360 g tripropylene glycol diacrylate into a container, stir, add 28 g photoinitiator TPO, and store in a dark place to obtain UV insulating adhesive.

[0034] Comparative Example 2: This comparative example differs from Example 1 in that acrylic acid is used instead of 4-acrylate benzoic acid.

[0035] (1) 800 mL of dichloromethane, 27 g (375 mmol) of acrylic acid, and 40 g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane were added to a reaction vessel, and 76 g of dicyclohexylcarbodiimide and 0.4 g of 4-dimethylaminopyridine were added in an ice-water bath. The mixture was stirred and reacted at 35° C. for 12 h, filtered, and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylate butylsiloxane) with the structural formula:

[0036]

[0037] (2) Add 1 kg of UV epoxy acrylate, 5 g of defoamer Deqian DAPRO AP7072, 300 g of tripropylene glycol diacrylate, and 60 g of di(acrylate butyl siloxane) into a container, stir, add 27 g of photoinitiator TPO, and store in a dark place to obtain UV insulating adhesive.

[0038] Comparative Example 3: This comparative example differs from Example 1 in that 1,8-octanediol is used instead of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane.

[0039] (1) 800 mL of dichloromethane, 72 g of 4-acrylated benzoic acid, and 21 g of 1,8-octanediol (143.6 mmol) were added to a reaction vessel, and 76 g of dicyclohexylcarbodiimide and 0.4 g of 4-dimethylaminopyridine were added in an ice-water bath. The mixture was stirred and reacted at 35° C. for 12 h, filtered, and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylated benzoate octane). The structural formula is

[0040] (2) Add 1 kg of UV epoxy acrylate, 5 g of defoamer Deqian DAPRO AP7072, 300 g of tripropylene glycol diacrylate, and 60 g of di(acrylate benzoate octane) into a container, stir, add 27 g of photoinitiator TPO, and store in a dark place to obtain UV insulating adhesive.

[0041] UV insulation adhesive was applied between two transparent polyester PET plates, cured in a 2kW UV curing machine for 50 seconds, left at room temperature for 24 hours, and the T-peel strength was tested according to the method of GB / T 2791-1995 standard.

[0042] The insulating adhesive was poured into a mold, cured in a 2kW UV curing machine for 180 seconds, and left at room temperature for 24 hours to prepare a casting sample. The volume resistivity was tested according to the method of GB / T 1410-2006 standard.

[0043] The impact strength of the casting specimens was tested according to the method of GB / T 2567-2021.

[0044] Table 1: Properties of UV insulation adhesive

[0045]

[0046]

[0047] Compared with Comparative Examples 1-3, the epoxy acrylate UV insulating adhesive of Examples 1-4 has good T-peel strength, volume resistivity and impact strength, and has excellent bonding performance, insulation performance and toughness. This is mainly because di(acrylate benzoate butyl siloxane) is added, which contains acrylate groups at both ends, replacing part of the tripropylene glycol diacrylate as a reactive diluent, and undergoes a photocuring reaction with the UV epoxy acrylate, thereby grafting the flexible and electrically insulating siloxane into the epoxy acrylate adhesive, significantly improving the impact strength and volume resistivity of the adhesive. At the same time, di(acrylate benzoate butyl siloxane) contains a benzoate structure similar to polyester PET, thereby improving the affinity and interface strength between the adhesive and the PET substrate, which is beneficial to improving the bonding performance with the PET substrate and having higher peel strength.

[0048] Although several embodiments of the present invention have been described herein, those skilled in the art will appreciate that modifications may be made to the embodiments herein without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as limitations on the scope of the present invention.

Claims

1. A UV insulating adhesive for improving the insulation performance of a battery shell, characterized in that: The UV insulating adhesive comprises 100 parts by weight of UV epoxy acrylate, 28-36 parts by weight of reactive diluent, 0.4-0.8 parts by weight of defoaming agent, and 2.5-3.3 parts of photoinitiator; The reactive diluent is composed of 13-30 parts by weight of an acrylate reactive diluent and 6-15 parts by weight of di(acrylate benzoate butylsiloxane); The structural formula of the di(acrylate benzoate butylsiloxane) reactive diluent is as follows:

2. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 1, characterized in that: The acrylate reactive diluent includes any one or a combination of tripropylene glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol triacrylate.

3. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 1, characterized in that: The photoinitiator includes photoinitiator TPO and photoinitiator 184.

4. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 1, characterized in that: The preparation method of the di(acrylate benzoate butyl siloxane) comprises: (1) adding sodium hydroxide solution and 4-hydroxybenzoic acid to a reaction vessel, stirring, then adding acryloyl chloride in an ice-water bath, stirring for 40-60 minutes, and then stirring and reacting at 15-25° C. for 1-1.5 hours, adding hydrochloric acid solution dropwise to adjust the pH, precipitating the precipitate, filtering, washing with water, and drying to obtain 4-acrylate benzoic acid; (2) Dichloromethane, 4-acrylated benzoic acid, and 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane were added to a reaction vessel, and dicyclohexylcarbodiimide and 4-dimethylaminopyridine were added in an ice-water bath. After stirring, the mixture was reacted at 20-35° C. for 12-18 hours, filtered, and the filtrate was rotary evaporated. The crude product was purified by silica gel column chromatography to obtain di(acrylated benzoate butylsiloxane).

5. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 4, characterized in that: The concentration of sodium hydroxide in (1) is 1.6-2 mol / L.

6. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 4, characterized in that: The mass ratio of 4-hydroxybenzoic acid to acryloyl chloride in (1) is 100:(66-72).

7. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 4, characterized in that: In the step (1), dilute hydrochloric acid is added dropwise to adjust the pH to 4-5; the mass fraction of the dilute hydrochloric acid solution is 5-8%.

8. The UV insulating adhesive for improving the insulation performance of a battery shell according to claim 4, characterized in that: The mass ratio of the (2) 4-acrylate benzoic acid, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, dicyclohexylcarbodiimide and 4-dimethylaminopyridine is (152-180):100:(190-208):(1-1.6).

9. A UV insulating adhesive for improving the insulation performance of a battery shell according to any one of claims 1 to 8, characterized in that: The preparation method comprises: adding UV epoxy acrylate, defoaming agent and active diluent into a container, adding a photoinitiator after stirring, and packaging and storing in a light-proof manner to obtain UV insulating glue for improving the insulation performance of a battery shell.

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