UV ink-jet glue as well as preparation method and application thereof

Abstract

The invention belongs to the field of UV glue, and relates to UV ink-jet glue as well as a preparation method and application thereof. The UV ink-jet glue contains an acrylate monomer, a hydrogenated polybutadiene modified acrylate oligomer, an anhydride modified acrylate oligomer, an adhesion promoter, a photoinitiator and an optional auxiliary agent, wherein the acrylate monomer at least contains an allyl hydrogen-containing acrylate monomer. The UV ink-jet glue provided by the invention is low in viscosity, can be applied to each position of a battery cell shell in an ink-jet manner, and after being irradiated and cured by a specific UV light source, double bonds in wet glue react, molecular chains capable of freely moving are mutually cross-linked and combined, the curing speed is high, the surface hardness is high, and the liquid glue is cured into a solid glue film; the adhesive film has extremely strong environmental aging resistance (salt mist resistance, heat and humidity resistance and the like) and electrolyte resistance effects, and can meet the application requirements of power batteries and energy storage batteries at the present stage.

Description

Technical Field

[0001] The present invention belongs to the field of batteries and relates to a UV inkjet glue, a preparation method thereof, and an application thereof. Background Art

[0002] Traditional battery cells achieve insulation protection by means of PET coating, but the disadvantages of this insulation protection method in terms of manufacturing yield, adhesion, aging resistance, etc. seriously restrict the development of battery cells. To overcome this problem, currently, technologies such as powder spraying, UV painting, and UV inkjet for insulation coatings have emerged. Among them, the powder spraying process has low efficiency, high cost, and is difficult to control the thickness; the waste rate of UV painting is large and the pollution is significant; UV inkjet can achieve fine control, has high utilization rate, and the coating adhesion strength far exceeds that of PET film. Therefore, it is the development direction with the highest attention in the industry.

[0003] However, the existing UV inkjet glues perform poorly in mechanical protection and reliability tests, and are prone to problems such as adhesion failure due to insufficient body strength, glue layer cracking due to the brittleness of the body, and electrolyte test breakdown due to poor resistance to environmental aging and electrolyte. They cannot meet the increasingly stringent requirements for battery cell protection. Summary of the Invention

[0004] The first object of the present invention is to provide a UV inkjet glue, which has low viscosity, can adapt to various inkjet processes, has a fast curing speed, high surface hardness, significant protection effect on the substrate, and at the same time has extremely high resistance to environmental aging and electrolyte.

[0005] The second object of the present invention is to provide a preparation method of the above-mentioned UV inkjet glue.

[0006] The third object of the present invention is to provide an application of the above-mentioned UV inkjet glue in the outer layer protection of battery cells.

[0007] Specifically, the UV inkjet glue provided by the present invention contains acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, anhydride-modified acrylate oligomers, adhesion promoters, photoinitiators, and optionally additives in a mass ratio of 100:(10 - 50):(5 - 20):(0.5 - 10):(5 - 30):(0 - 15), and at least one of the acrylate monomers contains an acrylate monomer with allyl hydrogen.

[0008] The preparation method of the UV inkjet glue provided by the present invention includes uniformly mixing acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, anhydride-modified acrylate oligomers, adhesion promoters, photoinitiators, and optionally additives to obtain the UV inkjet glue.

[0009] In addition, the present invention also provides an application of the UV inkjet glue in the outer layer protection of battery cells.

[0010] The UV inkjet glue provided by the present invention has a low viscosity and can apply glue to various positions of the battery cell housing by inkjet. After being irradiated and cured by a specific UV light source, the double bonds in the wet glue react, and the freely movable molecular chains crosslink and combine with each other. It has a fast curing speed, a high surface hardness, and the liquid glue is cured into a solid glue film. This glue film has extremely strong environmental aging resistance (salt spray resistance, heat and humidity resistance, etc.) and electrolyte resistance, and can meet the application requirements of power batteries and energy storage batteries at the present stage. Presumably, the reasons may be as follows: on the one hand, the acrylate monomer containing allyl hydrogen in the acrylate monomer contains allyl hydrogen that is active to free radicals and can act as a hydrogen donor. It acts together with the photoinitiator to form a stable allyl radical, thereby absorbing oxygen, extracting hydrogen, further converting into allyl hydroperoxide, decomposing into active radicals under light irradiation to continue to initiate polymerization, reducing the influence of oxygen inhibition of polymerization, accelerating the curing rate, increasing the surface curing reaction rate, improving the surface hardness, and improving the various anti-aging effects of the glue layer; on the other hand, the hydrogenated polybutadiene modified acrylate oligomer has a flexible long carbon chain structure and low polarity, and has strong tolerance to conventional solvents, which can effectively improve the mechanical properties of the glue film and at the same time improve the problems of swelling, dissolution and deformation of the glue film in solvents such as water and electrolyte; on the other hand, the anhydride modified acrylate oligomer can improve the compactness of the glue layer, improve the adhesion to the metal substrate, and reduce the damage of water molecules or solvent molecules to the glue film-metal interface during the aging process of the glue film. That is to say, the specific curing system of the present invention endows it with the advantages of fast curing speed and high surface hardness, and at the same time synergistically improves the environmental aging resistance and electrolyte resistance of the glue film from multiple dimensions. Detailed implementation manners

[0011] The UV inkjet glue provided by the present invention contains acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, anhydride-modified acrylate oligomers, adhesion promoters, photoinitiators, and optionally additives. Among them, the mass ratio of the acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, anhydride-modified acrylate oligomers, adhesion promoters, photoinitiators, and optionally additives is 100:(10 - 50):(5 - 20):(0.5 - 10):(5 - 30):(0 - 15). Specifically, based on 100 parts by mass of the acrylate monomers, the content of the hydrogenated polybutadiene-modified acrylate oligomers is 10 - 50 parts by weight, such as 10, 15, 20, 25, 30, 35, 40, 45, 50 parts by weight or any value therebetween; the content of the anhydride-modified acrylate oligomers is 5 - 20 parts by weight, such as 5, 8, 10, 12, 15, 18, 20 parts by weight or any value therebetween; the content of the adhesion promoter is 0.5 - 10 parts by weight, such as 0.5, 1, 2, 4, 6, 8, 10 parts by weight or any value therebetween; the content of the photoinitiator is 5 - 30 parts by weight, such as 5, 10, 15, 20, 25, 30 parts by weight or any value therebetween; the content of the additives is 0 - 15 parts by weight, such as 0, 0.1, 1, 3, 5, 8, 10, 12, 15 parts by weight or any value therebetween.

[0012] In a preferred embodiment, by weight percentage, the content of the acrylate monomers is 50 - 75%, the content of the hydrogenated polybutadiene-modified acrylate oligomers is 10 - 25%, the content of the anhydride-modified acrylate oligomers is 5 - 10%, the content of the adhesion promoter is 0.5 - 5%, the content of the photoinitiator is 5 - 15%, and the content of the additives is 0.1 - 10%. At this time, each component can play a better synergistic cooperation effect, and the obtained UV inkjet glue has better resistance to environmental aging and electrolyte resistance. Specifically, by weight percentage, the acrylate monomers can be exemplified as 50%, 55%, 60%, 65%, 70%, 75% or any value therebetween; the content of the hydrogenated polybutadiene-modified acrylate oligomers can be exemplified as 10%, 12%, 15%, 18%, 20%, 22%, 25% or any value therebetween; the content of the anhydride-modified acrylate oligomers can be exemplified as 5%, 6%, 7%, 8%, 9%, 10% or any value therebetween; the content of the adhesion promoter can be exemplified as 0.5%, 1%, 2%, 3%, 4%, 5% or any value therebetween; the content of the photoinitiator can be exemplified as 5%, 8%, 10%, 12%, 15% or any value therebetween; the content of the additives can be exemplified as 0.1%, 1%, 2%, 4%, 6%, 8%, 10% or any value therebetween.

[0013] In the present invention, the acrylate monomer contains at least an acrylate monomer containing allyl hydrogen. Among them, based on the total mass of the acrylate monomer, the proportion of the acrylate monomer containing allyl hydrogen is preferably 20-100 wt% (such as 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 100 wt% or any value therebetween). At this time, benefiting from the activity of the allylic hydrogen on the cyclopentene structure, the oxygen inhibition on the surface of the adhesive layer is weakened, the surface compactness is improved, and good aging resistance, water resistance, solvent resistance and chemical resistance can be imparted to the UV inkjet glue. In a preferred embodiment, the acrylate monomer further contains an acrylate monomer without allyl hydrogen, that is, the acrylate monomer is a composition of an acrylate monomer containing allyl hydrogen and an acrylate monomer without allyl hydrogen. At this time, the adhesive film has a fast surface curing effect. At the same time, the addition of other acrylate monomers also improves the toughness and strength of the adhesive film, and imparts better mechanical properties and chemical resistance to the adhesive film. Among them, the mass ratio of the acrylate monomer containing allyl hydrogen to the acrylate monomer without allyl hydrogen in the acrylate monomer is preferably 1:(1-6), such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or any value therebetween).

[0014] In the present invention, the acrylate monomer containing allyl hydrogen is a compound containing both an acrylic double bond and allyl hydrogen. The acrylate monomer containing allyl hydrogen has the structure shown in formula (1``):

[0015]

[0016] R` is an alkyl group of C1-C5. R is a group with allyl hydrogen, which can be a C1-C5 alkyl group with allyl hydrogen, a C3-C20 cycloalkyl group, a C6-C50 aralkyl group or a C6-C50 alkaryl group, and more preferably has the structure shown in any one of formula (1``-1), formula (1``-2), formula (1``-3), wherein, "*" represents the bonding end. The term "group with allyl hydrogen" refers to a group with an allyl structure and a hydrogen atom on the carbon atom bonded to the unsaturated double bond on the allyl group.

[0017]

[0018] CH2-CH=CH2-* Formula (1``-2),

[0019] CH3-CH=CH-* Formula (1``-3).

[0020] In the present invention, the acrylate monomer without allyl hydrogen is a compound containing an acrylic double bond but without allyl hydrogen. Further, examples of the acrylate monomer without allyl hydrogen may include: monofunctional acrylate monomers and / or polyfunctional acrylate monomers. Among them, examples of the monofunctional acrylate monomers may include at least one of isobornyl (meth)acrylate, trimethylcyclohexyl acrylate, benzyl acrylate, and ethoxyethoxyethyl acrylate. Examples of the polyfunctional acrylate monomers may include at least one of tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate, preferably a composition of tricyclodecane dimethanol diacrylate and pentaerythritol triacrylate. When the polyfunctional acrylate monomer is preferably selected from the composition of tricyclodecane dimethanol diacrylate and pentaerythritol triacrylate, the system has many crosslinking sites, a fast deep curing rate, a high crosslinking density, and can effectively improve the overall denseness and cohesive strength of the adhesive film.

[0021] In a preferred embodiment, the structure of the hydrogenated polybutadiene-modified acrylate oligomer is shown in formula (1):

[0022]

[0023] In formula (1), R 11 and R 12 are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, and R 13 and R 14 are each independently a linking group containing at least one of oxygen, nitrogen, or an alkylene group having 1 to 20 carbon atoms, and m and n are each independently 0 to 100. Among them, examples of the alkyl group having 1 to 5 carbon atoms may include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or neopentyl. Examples of the alkylene group having 1 to 20 carbon atoms may include methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, sec-butylene, tert-butylene, n-pentylene, isopentylene, n-hexylene, isohexylene, n-heptylene, n-octylene, n-nonylene, n-decylene, n-undecylene, n-dodecylene, n-tridecylene, n-tetradecylene, n-pentadecylene, n-hexadecylene, n-heptadecylene, n-octadecylene, n-nonadecylene, or n-eicosylene. Specifically, m and n may be 0, 1, 2, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, or any value between them.

[0024] In a preferred embodiment, R13 and R 14 has the structure shown in formula (1`), and its special alicyclic structure can endow the UV inkjet glue with better toughness and electrolyte resistance effect.

[0025]

[0026] In the present invention, the number-average molecular weight of the hydrogenated polybutadiene-modified acrylate oligomer is 100,000 g / mol or less, such as 100,000, 90,000, 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, 20,000, 10,000, 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3,000, 2,000, 1,000 g / mol or any value therebetween.

[0027] The present invention does not particularly limit the specific structure of the anhydride-modified acrylate oligomer, and any acrylate oligomer bonded with an anhydride is acceptable. Preferably, the anhydride-modified acrylate oligomer has the structure shown in formula (2). Its special carboxyl functional group can form a chemical bond with the surface of the metal substrate, increasing the interfacial adhesion between the adhesive film and the substrate. At the same time, the structure of its long carbon chain endows the resin with excellent flexibility, alleviates the curing shrinkage problem, and further improves the adhesion of the adhesive film to the substrate.

[0028]

[0029] In formula (2), R 21 and R 22 are each independently a long carbon chain containing an ether bond and / or an ester bond repeating segment, and the number of repeating units of the ether bond and ester bond repeating segment is 3 or more, preferably 3 - 20.

[0030] The present invention does not particularly limit the type of photoinitiator, and it can be various existing substances that can generate active free radicals through cleavage or hydrogen abstraction reactions after being irradiated with light to initiate the polymerization of monomers and oligomers. Specific examples include but are not limited to: at least one of 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2-methyl-2-(4-morpholinyl)-4'-(methylthio)propiophenone, 2-isopropylthioxanthone, benzoin diethyl ether, benzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-hydroxycyclohexyl phenyl ketone. Preferably, it is a combination of 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2-isopropylthioxanthone, benzoin diethyl ether, and benzophenone. When the photoinitiator is a composition of 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2-isopropylthioxanthone, benzoin diethyl ether, and benzophenone, it can effectively reduce the influence of surface oxygen inhibition polymerization, improve the surface curing effect, and at the same time take into account the advantages of deep curing, avoiding the problem of inability to cure through the bottom layer of the adhesive film.

[0031] The present invention does not particularly limit the type of adhesion promoter, and it can be various existing substances that can form chemical bonds with the metal surface to improve the adhesion of the glue to the substrate. Specific examples thereof include, but are not limited to, at least one of siloxane coupling agents, acrylated phosphates, and phthalate coupling agents.

[0032] In the present invention, the auxiliary agent can be various additives that can be added to the glue, and examples thereof include at least one of a leveling agent, a wetting and dispersing agent, an antifoaming agent, and a color paste. In a specific embodiment, based on the total weight of the UV inkjet glue, the auxiliary agent contains 1-10% of the color paste and 0.02-1% of the leveling aid. The content of the color paste can specifically be 1%, 2%, 4%, 6%, 8%, 10%, or any value therebetween. The content of the leveling aid can specifically be 0.02%, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, or any value therebetween.

[0033] The preparation method of the UV inkjet glue provided by the present invention includes uniformly mixing acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, acid anhydride-modified acrylate oligomers, an adhesion promoter, a photoinitiator, and optionally an auxiliary agent to obtain the UV inkjet glue. Among them, the mixing method is not particularly limited, and the materials can be added and mixed uniformly in any order.

[0034] The present invention also provides the application of the above UV inkjet glue in the outer layer protection of battery cells. In the specific application process, the UV inkjet glue is attached to the outer layer of the battery cell through an inkjet device, and then a protective glue layer is formed after photocuring.

[0035] The present invention will be described in detail below through examples. The examples are intended to explain the present invention and should not be construed as limiting the present invention. For those not specifying specific techniques or conditions in the examples, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0036] In the following examples and comparative examples, the hydrogenated polybutadiene-modified acrylate oligomer is CC-HPBA of Cheng Ci Corporation, which has the structure shown in formula (1) and R 13 and R 14It has the structure shown in formula (1ˋ); the anhydride-modified acrylate oligomer is SP277 of Songtai Co., Ltd., which has the structure shown in formula (2); the adhesion promoter is P-1M of Kyoeisha; the color paste is the 1156-nm color paste of Dongguan Thyssen New Materials Co., Ltd.; the additive is BYK330 of BYK Germany.

[0037] In the following examples and comparative examples, the parts of each substance refer to parts by weight.

[0038] Example 1: Preparation of UV-curable glue

[0039] According to the parts ratio in Table 1, dicyclopentenyloxyethyl acrylate (DCPA), benzyl acrylate (BZA), isobornyl acrylate (IBOA), tricyclodecane dimethanol diacrylate (TCDDA), pentaerythritol triacrylate (PET3A), color paste, phosphate adhesion promoter (P-1M), leveling agent BYK333, 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), and isopropylthioxanthone (ITX) were added to the reaction kettle and stirred at a speed of 500 rpm until evenly mixed. Then, benzoin diethyl ether (651) and benzophenone (BP) were added and stirred at a speed of 500 rpm until evenly mixed. After that, hydrogenated polybutadiene acrylate and anhydride-modified acrylate were added and stirred at a speed of 1000 rpm until evenly mixed, and then filtered and discharged to obtain UV inkjet glue.

[0040] Examples 2-7: Preparation of UV-curable glue

[0041] The UV inkjet glue was prepared according to the method of Example 1, except that the amounts of each component were adjusted according to the ratio in Table 1, and the other conditions were the same as those in Example 1, to obtain UV inkjet glue.

[0042] Example 8: Preparation of UV-curable glue

[0043] The UV inkjet glue was prepared according to the method of Example 1, except that benzyl acrylate (BZA), isobornyl acrylate (IBOA), tricyclodecane dimethanol diacrylate (TCDDA), and pentaerythritol triacrylate (PET3A) were all replaced with the same weight parts of dicyclopentenyloxyethyl acrylate (DCPA), and the other conditions were the same as those in Example 1, to obtain UV inkjet glue.

[0044] Comparative Example 1: Preparation of UV-curable glue

[0045] The UV inkjet glue was prepared according to the method of Example 1, except that the hydrogenated polybutadiene-modified acrylate oligomer was replaced with the same weight parts of anhydride-modified acrylate oligomer, and the other conditions were the same as those in Example 1, to obtain UV inkjet glue.

[0046] Comparative Example 2: Preparation of UV Curable Glue

[0047] Prepare the UV inkjet glue according to the method of Example 1, except that the anhydride-modified acrylate oligomer is replaced with a hydrogenated polybutadiene-modified acrylate oligomer of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0048] Comparative Example 3: Preparation of UV Curable Glue

[0049] Prepare the UV inkjet glue according to the method of Example 1, except that the dicyclopentenyl acrylate (DCPA) is replaced with isobornyl acrylate (IBOA) of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0050] Comparative Example 4: Preparation of UV Curable Glue

[0051] Prepare the UV inkjet glue according to the method of Example 1, except that the hydrogenated polybutadiene-modified acrylate oligomer is replaced with a polyurethane acrylate oligomer (6115J-80 of Changxing Materials Industry Co., Ltd.) of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0052] Comparative Example 5: Preparation of UV Curable Glue

[0053] Prepare the UV inkjet glue according to the method of Example 1, except that the anhydride-modified acrylate oligomer is replaced with a polyurethane acrylate oligomer (6115J-80 of Changxing Materials Industry Co., Ltd.) of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0054] Comparative Example 6: Preparation of UV Curable Glue

[0055] Prepare the UV inkjet glue according to the method of Example 1, except that both the hydrogenated polybutadiene-modified acrylate oligomer and the anhydride-modified acrylate oligomer are replaced with a polyurethane acrylate oligomer (6115J-80 of Changxing Materials Industry Co., Ltd.) of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0056] Comparative Example 7: Preparation of UV Curable Glue

[0057] Prepare the UV inkjet glue according to the method of Example 1, except that the dicyclopentenyl acrylate (DCPA) is replaced with 2-ethoxyethoxy (meth)acrylate monomer (VEEA) of the same weight portion, and the other conditions are the same as those in Example 1 to obtain the UV inkjet glue.

[0058]

[0059] Test Example

[0060] (1) Viscosity test: Test using a rotational rheometer HAAKE MARS40, with test parameters of 25 °C, rotor No. 52, and shear rate of 20 -1 . The obtained results are shown in Table 2. From the results in Table 2, it can be seen that the viscosity of the UV inkjet glue provided by the present invention at room temperature is ≤50 cps, meeting the requirements of the inkjet device and enabling the process requirements of continuous production to be achieved.

[0061] (2) LED curing surface dryness: Control the film thickness at 100 ± 2 μm, and cure using light with a wavelength of 395 nm under the condition of 10 w / cm 2 . Evaluate the time required for the surface to be completely cured and touch-dry. The obtained results are shown in Table 2. Among them, NG represents incomplete surface drying. From the results in Table 2, it can be seen that the UV inkjet glue provided by the present invention has a fast curing speed, can meet the requirement of complete surface drying within 5 s, can adapt to the actual requirements of rapid production, while the LED curing effect of the glue in the comparative example is not ideal, and short-time surface drying cannot be achieved, which will also have an adverse impact on subsequent tests.

[0062] (3) Shear test: Prepare shear specimens for testing. After overlapping two shear specimens, bond them with a two-component PU structural adhesive, control the adhesive layer thickness at 0.25 mm, cure at 80 °C for 4 h, and after cooling, conduct a shear force test in accordance with GBT7124 / ISO4587. The test temperature is 25 °C and the tensile speed is 5 mm / min. The obtained results are shown in Table 2. From the results in Table 2, it can be seen that compared with the comparative example, the shear strength of the UV inkjet glue provided by the present invention before and after aging is much higher. The shear strength after 1000 h of double 85 damp heat aging is still greater than 10 MPa, showing strong tolerance to damp heat aging.

[0063] (4) Adhesion test: Coat the UV inkjet glue obtained from the above examples and comparative examples on aluminum alloy shear specimens, and cure using light with a wavelength of 395 nm under the condition of 10 w / cm 2 for 5 s to form a film with a thickness of 100 ± 2 μm. Use DIN EN ISO 2409 (Paints - Cross - cut test for coatings) to test the adhesion of the film before and after 1000 h of double 85 damp heat aging. The obtained results are shown in Table 2. From the results in Table 2, it can be seen that before and after damp heat aging, the UV inkjet glue provided by the present invention has strong adhesion on the aluminum layer surface, and there will be no problems of decreased adhesion and glue layer peeling after long-term aging.

[0064] (5) Bending test: Coat the UV inkjet glue obtained from the above examples and comparative examples on aluminum alloy shear specimens, and cure using light with a wavelength of 395 nm under the condition of 10 w / cm 2Cure for 5 s under the conditions to form a film with a thickness of 100 ± 2 μm as the test sample. Bend the test sample 90° on a shaft rod with a curvature radius of 25 mm, observe the surface state of the adhesive layer. If there are no obvious cracks or damages, it is judged as pass; if cracking or damage appears, it is judged as NG. The obtained results are shown in Table 2. It can be seen from the results in Table 2 that the UV inkjet glue provided by the present invention can still ensure the integrity of the adhesive layer during bending with a large diameter, and there will be no cracking or peeling. When the battery cell with this UV glue as the outer wrapping layer undergoes large deformation, the UV adhesive layer can still play an insulating and protective role.

[0065] (6) Insulation resistance: Coat the UV inkjet glue obtained from the above examples and comparative examples on aluminum cut slices, and use light with a wavelength of 395 nm at 10 w / cm 2 Cure for 5 s under the conditions to form a film with a thickness of 100 ± 2 μm. Use a GPT-9803 voltage / insulation resistance tester to test the insulation resistance before and after 1000 h of double 85 damp heat aging. Adjust the test conditions to DC 1000 V, 10 s, click the test, and read the test results. The obtained results are shown in Table 2. It can be seen from the results in Table 2 that the UV inkjet glue provided by the present invention has an insulation resistance value ≥ 10 GΩ under DC 1000 V, exceeding the instrument range, and is not affected by damp heat aging, which can meet the actual use requirements for battery cell protection.

[0066] (7) Withstand voltage test: Coat the UV inkjet glue obtained from the above examples and comparative examples on aluminum cut slices, and use light with a wavelength of 395 nm at 10 w / cm 2 Cure for 5 s under the conditions to form a film with a thickness of 100 ± 2 μm. Use a GPT-9803 voltage / insulation resistance tester to conduct a withstand voltage test before and after 1000 h of double 85 damp heat aging. Adjust the test conditions to AC 2230 V 60 s / DC 4000 V 60 s. If the leakage current < 0.1 mA, it is judged as pass; if the leakage current ≥ 0.1 mA, it is judged as NG. Click the test, and read the test results. The obtained results are shown in Table 2. It can be seen from Table 2 that the UV inkjet glue obtained from each example and comparative example has good insulation and withstand voltage effects. However, in the comparative example, the leakage current exceeds the standard or even the adhesive layer is punctured after aging, while no obvious withstand voltage failure phenomenon appears in the examples after aging, which can meet the actual use requirements for battery cell protection.

[0067] (8) Boiling water resistance test: Coat the UV inkjet glue obtained from the above examples and comparative examples on aluminum cut slices, and use light with a wavelength of 395 nm at 10 w / cm 2Cure for 5 s under the conditions to form a diaphragm with a thickness of 100 ± 2 μm as a test sample. Place the test sample in boiling water for 72 h, take it out, dry it and let it stand for 1 h, then test the adhesion and pressure resistance, and the evaluation criteria are the same as above. The obtained results are shown in Table 2. It can be seen from the results in Table 2 that the UV inkjet glue provided by the present invention can still maintain qualified adhesion and pressure resistance performance after the severe test of boiling in boiling water for 72 h, and can meet the actual use requirements of battery cell protection.

[0068] (9) Room temperature electrolyte resistance test: Coat the UV inkjet glue obtained in the above examples and comparative examples on the cut aluminum sheets, and use light with a wavelength of 395 nm at 10 w / cm 2 Cure for 5 s under the conditions to form a diaphragm with a thickness of 100 ± 2 μm as a test sample. Drop 0.5 g of electrolyte on the test sample, cover it with a cover glass, put it into a sealed container, place it at 25 °C for 48 h, take it out, dry it and let it stand for 1 h, then conduct adhesion test, pressure resistance test and appearance observation. If the adhesion ≥ 4B, the leakage current of the pressure resistance test ≤ 0.1 mA, and there is no obvious wrinkling and peeling on the appearance, it is judged as pass; if the adhesion < 4B, the leakage current of the pressure resistance test > 0.1 MA, and there is an obvious change in the appearance, and any one of these phenomena is judged as NG.

[0069] High temperature electrolyte resistance test: Coat the UV inkjet glue obtained in the above examples and comparative examples on the cut aluminum sheets, and use light with a wavelength of 395 nm at 10 w / cm 2 Cure for 5 s under the conditions to form a diaphragm with a thickness of 100 ± 2 μm as a test sample. Put the test sample into a sealed container, add an appropriate amount of electrolyte enough to completely immerse the sample, place it at 85 °C for 2 h, take it out, dry it and let it stand for 1 h, then conduct adhesion test, pressure resistance test and appearance observation. If the adhesion ≥ 4B, the leakage current of the pressure resistance test ≤ 0.1 mA, and there is no obvious wrinkling and peeling on the appearance, it is judged as pass; if the adhesion < 4B, the leakage current of the pressure resistance test > 0.1 MA, and there is an obvious change in the appearance, and any one of these phenomena is judged as NG.

[0070] The obtained results are shown in Table 2. It can be known from the results in Table 2 that the adhesive layers provided by the examples can still maintain the same appearance and adhesion after the room temperature or high temperature electrolyte aging test, and the insulation performance has no obvious attenuation. The adhesive layers of the comparative examples show peeling on the appearance after the room temperature or high temperature electrolyte thermal aging, and are judged as NG.

[0071] (11) Salt spray test: Coat the UV inkjet glue obtained in the above examples and comparative examples on the cut aluminum sheets, and use light with a wavelength of 395 nm at 10 w / cm 2Cure for 5 s under the conditions to form a diaphragm with a thickness of 100 ± 2 μm as a test sample. The test method refers to the salt spray requirements of GB / T31467.3, and the aging experiment is carried out at the severity level (5). Test the adhesion and withstand voltage, and the evaluation criteria are the same as above. The obtained results are shown in Table 2. It can be seen from the results in Table 2 that the UV adhesive layer provided by the present invention can still have excellent adhesion to the aluminum layer after salt spray aging, and at the same time, the insulation and withstand voltage performance has no obvious attenuation, which can meet the requirements of the insulation protection of the battery cell.

[0072]

[0073] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principle and purpose of the present invention.

Claims

1. A UV inkjet glue, characterized in that: The UV inkjet glue contains acrylate monomers, hydrogenated polybutadiene-modified acrylate oligomers, anhydride-modified acrylate oligomers, adhesion promoters, photoinitiators and optional auxiliary agents in a mass ratio of 100:(10-50):(5-20):(0.5-10):(5-30):(0-15), and the acrylate monomers contain at least acrylate monomers containing allyl hydrogen.

2. The UV inkjet glue according to claim 1, characterized in that: In weight percentage, the content of the acrylate monomer is 50-75%, the content of the hydrogenated polybutadiene modified acrylate oligomer is 10-25%, the content of the anhydride modified acrylate oligomer is 5-10%, the content of the adhesion promoter is 0.5-5%, the content of the photoinitiator is 5-15%, and the content of the auxiliary agent is 0.1-10%.

3. The UV inkjet glue according to claim 1, characterized in that: The acrylate monomer further contains an acrylate monomer that does not contain allylic hydrogen; Preferably, the mass ratio of the acrylate monomer containing allyl hydrogen to the acrylate monomer not containing allyl hydrogen in the acrylate monomer is 1:(1-6); Preferably, the acrylate monomer containing allylic hydrogen is dicyclopentenyl (meth)acrylate and / or tricyclopentenyl acrylate; Preferably, the acrylate monomer not containing allylic hydrogen is a monofunctional acrylate monomer and / or a multifunctional acrylate monomer; preferably, the monofunctional acrylate monomer is selected from at least one of isobornyl (meth)acrylate, trimethylcyclohexyl acrylate, benzyl acrylate and ethoxyethoxyethyl acrylate; preferably, the multifunctional acrylate monomer is selected from at least one of tricyclodecane dimethanol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate and tris(2-hydroxyethyl)isocyanuric acid triacrylate.

4. The UV inkjet glue according to claim 1, characterized in that: The structure of the hydrogenated polybutadiene modified acrylate oligomer is shown in formula (1): In formula (1), R 11 and R 12 are each independently hydrogen or C1-C5 alkyl, R 13 and R 14 Each is independently a linking group containing at least one of oxygen, nitrogen or a C1-C20 alkylene group, and m and n are each independently 0 to 100.

5. The UV inkjet glue according to claim 4, characterized in that: R 13 and R 14 It has the structure shown in formula (1):

6. The UV inkjet glue according to claim 1, characterized in that: The number average molecular weight of the hydrogenated polybutadiene modified acrylate oligomer is less than 100000 g / mol.

7. The UV inkjet glue according to claim 1, characterized in that: The anhydride-modified acrylate oligomer has a structure shown in formula (2): In formula (2), R 21 and R 22 Each is independently a long carbon chain containing a repeating segment of an ether bond and / or an ester bond, and the number of repeating units of the repeating segment of the ether bond and the ester bond is 3 or more.

8. The UV inkjet glue according to any one of claims 1 to 7, characterized in that: The adhesion promoter is selected from at least one of a siloxane coupling agent, an acrylated phosphate ester and a phthalate coupling agent; The photoinitiator is selected from at least one of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-2-(4-morpholinyl)-4'-(methylthio)propiophenone, 2-isopropylthioxanthone, benzoin diethyl ether, benzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone and 1-hydroxycyclohexyl phenyl ketone, preferably a combination of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-isopropylthioxanthone, benzoin diethyl ether and benzophenone; The auxiliary agent is selected from at least one of a leveling agent, a wetting and dispersing agent, a defoaming agent and a color paste.

9. The method for preparing the UV inkjet glue according to any one of claims 1 to 8, characterized in that: The method comprises uniformly mixing acrylate monomers, hydrogenated polybutadiene modified acrylate oligomers, anhydride modified acrylate oligomers, adhesion promoters, photoinitiators and optional auxiliary agents to obtain the UV inkjet glue.

10. Use of the UV inkjet glue according to any one of claims 1 to 8 in the outer layer protection of a battery cell.

Images