Ink-jet coding tape for power batteries and preparation method therefor

Abstract

The present invention discloses an ink-jet coding tape for power batteries. The ink-jet coding tape comprises, from top to bottom in sequence, a pressure-sensitive adhesive layer, an ink layer, a substrate layer, and a release layer. The pressure-sensitive adhesive layer is an acrylate pressure-sensitive adhesive, and the ink layer is a UV light-curable ink. In the present invention, toluene diisocyanate, a maleic anhydride-based curing agent, and melamine-formaldehyde resin are used in combination as a curing agent, so that QR codes can be rapidly recognized while excellent peel strength is maintained. The ink uses polysiloxane acrylate in combination with bisphenol A epoxy acrylate, which enables photocuring of the ink. The ink has good bonding characteristics with the acrylate pressure-sensitive adhesive, the ink-jet codes can be rapidly recognized, and the codes are not prone to falling off.

Description

A coding tape for power batteries and its preparation method Technical Field

[0001] This invention relates to the field of lithium battery assembly, and more specifically to a coding tape for power batteries and its preparation method. Background Technology

[0002] With technological advancements, power batteries are increasingly widely used in transportation. These batteries boast high energy density, high power output, and long lifespans. To reduce the frequency and cost of battery replacements, continuous research and development of safer and more reliable power batteries is essential. As the application of power batteries grows, their safety control requires higher levels of traceability. Inkjet printing on power batteries enables continuous monitoring. However, this process requires immersion in electrolyte, placing higher demands on the performance of the adhesive tape. Therefore, developing an inkjet printing tape that is resistant to electrolyte corrosion, has high adhesion, and allows for rapid code identification is crucial.

[0003] Chinese invention patent CN115584217B discloses an identifiable termination tape. By combining suitable photoactive oligomers, macromolecular carboxyl-terminated acrylic resins, and photoinitiators, a stable polymer network is constructed, enabling a strong adhesion between the colored coating and the selected suitable coating substrate. However, the adhesive layer has low tackiness, and the bonding strength needs to be improved. Chinese invention patent CN117683486A discloses an adhesive and a coding tape using the same. By simultaneously introducing modified styrene-isoprene-styrene block copolymers, hydrogenated nitrile rubber, amorphous polyalphaolefins, tackifying resins, and reactive liquid rubbers, the electrolyte resistance and chemical stability of the coding tape can be enhanced. However, the ink is prone to fading, and the adhesion between the adhesive and the ink is poor. Summary of the Invention

[0004] In order to develop a coding tape that is resistant to electrolyte corrosion, has high viscosity, and allows for rapid identification of the coding, the first aspect of the present invention provides a coding tape for power batteries, wherein the coding tape comprises, from top to bottom, a pressure-sensitive adhesive layer, an ink layer, a substrate layer, and a release layer; the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive, and the ink layer is a UV-curable ink.

[0005] In a preferred embodiment, the raw materials for preparing the UV-curable ink, by weight, include 1-3 parts of dispersant, 0.4-2.2 parts of surfactant, 18-28 parts of UV oligomer, 55-85 parts of UV monomer, 5-15 parts of photoinitiator, 0.2-2.2 parts of light stabilizer, 0.2-2.2 parts of heat stabilizer, and 2-5 parts of carbon black.

[0006] In a preferred embodiment, the UV oligomer is a polysiloxane acrylate, and the UV monomer is an epoxy acrylate monomer.

[0007] In a preferred embodiment, the UV monomer is a bisphenol A epoxy acrylate monomer, and more preferably, the UV monomer is ethoxylated trimethylolpropane triacrylate (TMPTA).

[0008] In a preferred embodiment, the dispersant is tripropylene glycol diacrylate, the surfactant is hexadecyltrimethylammonium bromide, the photoinitiator is phenylacetone, the light stabilizer is Chimassorb 944, and the heat stabilizer is Irganox 1010.

[0009] In a preferred embodiment, the raw materials for preparing the acrylate pressure-sensitive adhesive, by weight, include 34-91 parts of acrylic monomer, 0.1-1 parts of initiator, 3-10 parts of curing agent, 4-6 parts of color paste, and also include solvent I, solvent II and solvent III.

[0010] In a preferred embodiment, the acrylic monomers, by weight, include 1-3 parts acrylic acid, 1-3 parts hydroxypropyl acrylate, 1-10 parts isobornyl acrylate, 1-5 parts glycidyl methacrylate, 25-45 parts isooctyl acrylate, 1-5 parts lauryl methacrylate, 1-5 parts cyclohexyl acrylate, 1-5 parts cyclopentyl acrylate, 1-5 parts cyclohexylmethyl acrylate, and 1-5 parts dicyclopentadienyl acrylate.

[0011] In a preferred embodiment, the curing agent is selected from at least one of isocyanate curing agents, maleic anhydride curing agents, and melamine-formaldehyde resin.

[0012] In a preferred embodiment, the isocyanate curing agent is toluene diisocyanate. The maleic anhydride curing agent is Narconate 100 maleic anhydride. The melamine-formaldehyde resin is Resimene 710.

[0013] In a preferred embodiment, the curing agent is a combination of toluene diisocyanate and Narconate 100 maleic anhydride in a weight ratio of (1-5):(2-5); preferably, the weight ratio of toluene diisocyanate and Narconate 100 maleic anhydride is 3:4.

[0014] In a preferred embodiment, the curing agent is a combination of toluene diisocyanate, Narconate 100 maleic anhydride, and Resimene 710 melamine-formaldehyde resin.

[0015] In a preferred embodiment, the weight ratio of toluene diisocyanate, Narconate 100 maleic anhydride, and Resimene 710 melamine-formaldehyde resin is (1-4):(1-3):(1-3).

[0016] In a preferred embodiment, the weight ratio of toluene diisocyanate, Narconate 100 maleic anhydride, and Resimene 710 melamine-formaldehyde resin is 2.5:2:2.

[0017] During the experiment, the applicant discovered that by combining toluene diisocyanate with maleic anhydride curing agents, a pressure-sensitive adhesive with a thickness of 25 μm could be obtained, which could achieve high adhesion and electrolyte resistance in battery tape. The applicant speculated that the possible reason is that the -NCO in toluene diisocyanate and maleic anhydride curing agents can react with acrylic monomers to form a dense cross-linked network, thereby improving the electrolyte resistance of the adhesive layer.

[0018] During the experiment, the inventors further discovered that when toluene diisocyanate, maleic anhydride curing agents, and melamine-formaldehyde resin are combined as curing agents, the QR code can be quickly identified while maintaining excellent peel strength. The reason may be that the introduction of melamine-formaldehyde resin can expand the cross-linking mode of the cross-linking network, resulting in high recognition of the ink after light curing. Combined with the high viscosity of the pressure-sensitive adhesive, the QR code can be quickly identified.

[0019] In a preferred embodiment, the initiator is benzoyl peroxide.

[0020] In a preferred embodiment, the color paste is phthalocyanine blue paste or cobalt green paste.

[0021] In a preferred embodiment, solvent I is an alkane and solvent II is an ester solvent.

[0022] In a preferred embodiment, solvent I is heptane; solvent II is ethyl acetate; and solvent III is toluene.

[0023] In this invention, inkjet printing is bonded to acrylic pressure-sensitive adhesive using alkane, ester solvents, and toluene as solvents. This avoids degrading the inkjet printing, extends its service life, and prevents it from falling off.

[0024] A second aspect of the present invention provides a method for preparing inkjet printing tape for power batteries, comprising the following steps:

[0025] S1 is used to prepare an acrylic pressure-sensitive adhesive for later use;

[0026] S2 is used to prepare UV-curable ink for later use;

[0027] S3 involves spraying UV-curable ink onto a substrate layer, followed by UV curing at a light intensity of 100-120 mW / cm². 2 ;

[0028] S4 provides a release layer on the side of the substrate layer away from the ink layer;

[0029] S5 involves extruding and coating an acrylic pressure-sensitive adhesive over the cured ink layer;

[0030] After curing with S6, the tape is wound up to obtain a semi-finished product.

[0031] As a preferred embodiment, the method for preparing the inkjet printing tape for power batteries includes the following steps:

[0032] S1 is used to prepare an acrylic pressure-sensitive adhesive for later use;

[0033] S2 is used to prepare UV-curable ink for later use;

[0034] S3 involves spraying UV-curable ink onto a cleaned substrate layer, followed by UV curing at a light intensity of 100-120 mW / cm². 2 ;

[0035] S4 has a release layer on the side of the substrate layer away from the ink layer, and is cured at 60-120℃ for 5-20 minutes.

[0036] S5 involves extruding and coating an acrylic pressure-sensitive adhesive over the cured ink layer;

[0037] S6 is placed at 60-120℃ for 5-12 minutes for heat preservation and curing, then dried and wound up to obtain semi-finished tape.

[0038] As a preferred embodiment, the preparation method of the acrylic pressure-sensitive adhesive in step S1 is as follows:

[0039] M1 mixes acrylic monomers, introduces nitrogen gas, heats to 50-70°C under nitrogen protection, stirs slowly for 5-7 hours, then adds initiator, and continues the reaction for 4-6 hours to obtain a pre-reacted colloid.

[0040] M2 is added to solvent I to dilute and stir the pre-reacted colloid. During stirring, the curing agent is added and mixed evenly. Then, the color paste is added and stirred evenly to obtain the pre-cured colloid. Solvents II and III are added to dilute it to a coatable state for later use.

[0041] As a preferred embodiment, the preparation method of the UV-curable ink in step S2 is as follows:

[0042] Mix the raw materials and stir at room temperature for 20-40 minutes until fully mixed.

[0043] In a preferred embodiment, the amount of solvent I added is such that the mass concentration of the pre-reacted colloid is 30-50%, preferably 40%.

[0044] In a preferred embodiment, the mass ratio of solvent II to pre-cured colloid is (1-3):1; solvent III is 5-7% of the mass of pre-cured colloid, preferably, the mass ratio of solvent II to pre-cured colloid is 1:1; and solvent III is 6% of the mass of pre-cured colloid.

[0045] In a preferred embodiment, the photocuring time in step S3 is 10-50 s. Preferably, the photocuring time in step S3 is 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, or 50 s.

[0046] In a preferred embodiment, the coating thickness of the acrylic pressure-sensitive adhesive in step S5 is 5-50 μm. Preferably, the coating thickness of the acrylic pressure-sensitive adhesive in step S5 is 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm.

[0047] In a preferred embodiment, the substrate layer is a PET substrate with a thickness of 25-75 μm. Preferably, the thickness of the PET substrate is 25, 50, or 75 μm.

[0048] In a preferred embodiment, the release layer is a non-silicone release agent, which is Polywax 1000 polyethylene wax. Beneficial effects

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The inkjet tape for power batteries described in this invention is a pressure-sensitive adhesive with a thickness of 25 μm obtained by combining toluene diisocyanate and maleic anhydride curing agent, and has good electrolyte resistance.

[0051] (2) The power battery inkjet tape of the present invention uses toluene diisocyanate, maleic anhydride curing agent and melamine formaldehyde resin as curing agent. The QR code can be quickly identified while maintaining excellent peel strength.

[0052] (3) The inkjet tape for power batteries described in this invention uses a combination of polysiloxane acrylate and bisphenol A epoxy acrylate in the ink, which can achieve photocuring of the ink. The ink and the acrylate hypoallergenic adhesive have good bonding characteristics, and the inkjet can be quickly identified and is not easy to fall off.

[0053] (4) The power battery inkjet tape of the present invention has pressure-sensitive adhesive and inkjet printing on the same side of the substrate. The ink has good adhesion to the substrate, will not be easily wiped off and will not be faded by the solvent of the pressure-sensitive adhesive. The ink and adhesive also have good bonding adhesion.

[0054] (5) The power battery inkjet tape of the present invention can achieve the effect of easy QR code recognition, high efficiency and low overall cost by spraying QR codes and clear codes, without investing in expensive laser marking machines. Detailed Implementation Example 1

[0055] A coding tape for power batteries, comprising, from top to bottom, a pressure-sensitive adhesive layer, an ink layer, a substrate layer, and a release layer; the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive, and the ink layer is a UV-curable ink.

[0056] By weight, the raw materials for preparing the UV-curable ink include 2 parts dispersant, 1.3 parts surfactant, 23 parts UV oligomer, 70 parts UV monomer, 10 parts photoinitiator, 1.2 parts light stabilizer, 1.2 parts heat stabilizer, and 3 parts carbon black.

[0057] The UV oligomer is polysiloxane acrylate, and the UV monomer is ethoxylated trimethylolpropane triacrylate.

[0058] The polysiloxane acrylate is Sartoma CN9800.

[0059] The dispersant is tripropylene glycol diacrylate, and the surfactant is hexadecyltrimethylammonium bromide. The photoinitiator is phenylacetone. The light stabilizer is Chimassorb 944, and the heat stabilizer is Irganox 1010.

[0060] By weight, the raw materials for preparing the acrylate pressure-sensitive adhesive include 62.5 parts of acrylic monomer, 0.5 parts of initiator, 7 parts of curing agent, 5 parts of color paste, and also solvent I, solvent II and solvent III.

[0061] By weight, the acrylic monomers include 2 parts acrylic acid, 2 parts hydroxypropyl acrylate, 5 parts isoborneol acrylate, 3 parts glycidyl methacrylate, 35 parts isooctyl acrylate, 3 parts lauryl methacrylate, 3 parts cyclohexyl acrylate, 3 parts cyclopentyl acrylate, 3 parts cyclohexyl methyl acrylate, and 3 parts dicyclopentadiene acrylate.

[0062] The curing agent is a combination of toluene diisocyanate and Narconate 100 maleic anhydride in a weight ratio of 3:4.

[0063] The initiator is benzoyl peroxide. The color paste is phthalocyanine blue paste.

[0064] Solvent I is heptane; solvent II is ethyl acetate; and solvent III is toluene.

[0065] A method for preparing inkjet printing tape for power batteries includes the following steps:

[0066] S1 is used to prepare an acrylic pressure-sensitive adhesive for later use;

[0067] S2 is used to prepare UV-curable ink for later use;

[0068] S3 sprays UV-curable ink onto a cleaned substrate layer, then cures it with a light intensity of 110 mW / cm². 2 ;

[0069] S4 has a release layer on the side of the substrate layer away from the ink layer, and is cured at 100°C for 15 minutes.

[0070] S5 involves extruding and coating an acrylic pressure-sensitive adhesive over the cured ink layer;

[0071] S6 is placed at 100℃ for 10 minutes to cure and then dried, and then rolled up to obtain a semi-finished tape.

[0072] The preparation method of the acrylic pressure-sensitive adhesive in step S1 is as follows:

[0073] M1 mixes acrylic monomers, introduces nitrogen gas, heats to 60°C under nitrogen protection, stirs slowly for 0.5 h, then adds initiator, and continues the reaction for 5 h to obtain a pre-reacted colloid;

[0074] M2 is added to solvent I to dilute and stir the pre-reacted colloid. During stirring, the curing agent is added and mixed evenly. Then, the color paste is added and stirred evenly to obtain the pre-cured colloid. Solvents II and III are added to dilute it to a coatable state for later use.

[0075] The amount of solvent I added is such that the mass concentration of the pre-reacted colloid is 40%. The mass ratio of solvent II to the pre-cured colloid is 1:1; and solvent III is 6% of the mass of the pre-cured colloid.

[0076] The preparation method of the UV-curable ink in step S2 is as follows:

[0077] Mix the raw materials and stir at room temperature for 60 minutes. Once fully mixed, set aside for later use.

[0078] The photocuring time in step S3 is 30 seconds.

[0079] In step S5, the coating thickness of the acrylic pressure-sensitive adhesive is 10 μm.

[0080] The substrate layer is a PET substrate with a thickness of 25 μm.

[0081] The release layer is a non-silicone release agent, Polywax 1000 polyethylene wax. Example 2

[0082] A coding tape for power batteries and its preparation method are disclosed. The specific implementation method is the same as that in Example 1, except that the coating thickness of the acrylic pressure-sensitive adhesive in step S5 is 5 μm. Example 3

[0083] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as in Example 1, except that the coating thickness of the acrylic pressure-sensitive adhesive in step S5 is 15 μm. Example 4

[0084] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as that in Example 1, except that the photocuring time in step S3 is 50s. Example 5

[0085] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as in Example 1, except that the photocuring time in step S3 is 10s. Example 6

[0086] A coding tape for power batteries and its preparation method are disclosed. The specific implementation method is the same as that in Example 4, except that the curing agent is Resimene 710 melamine-formaldehyde resin. Example 7

[0087] A coding tape for power batteries and its preparation method are disclosed. The specific implementation method is the same as that in Example 6, except that the curing agent is a combination of toluene diisocyanate and Resimene 710 melamine-formaldehyde resin in a weight ratio of 3.5:3. Example 8

[0088] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as that in Example 6, except that the curing agent is a combination of Narconate 100 maleic anhydride and Resimene 710 melamine-formaldehyde resin in a weight ratio of 3.5:3. Example 9

[0089] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as that in Example 6, except that the curing agent is a combination of toluene diisocyanate, Narconate 100 maleic anhydride, and Resimene 710 melamine-formaldehyde resin in a weight ratio of 2.5:2:2. Example 10

[0090] A coding tape for power batteries and its preparation method are disclosed. The specific implementation method is the same as that in Example 6, except that the curing agent is Narconate 100 maleic anhydride.

[0091] Comparative Example 1

[0092] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as in Example 4, except that the amount of curing agent added is 0 parts by weight.

[0093] Comparative Example 2

[0094] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as that in Example 4, except that the coating thickness of the acrylate pressure-sensitive adhesive in step S5 is 1 μm.

[0095] Comparative Example 3

[0096] A coding tape for power batteries and its preparation method are described. The specific implementation method is the same as that in Example 4, except that the coating thickness of the acrylic pressure-sensitive adhesive in step S5 is 100 μm.

[0097] Performance testing

[0098] 1. Viscosity test:

[0099] The prepared product was made into samples, and the 180° peel strength was tested according to GB / T 2792-2014. The ambient temperature was maintained at 23±2℃, the humidity at 50±5%, and the test speed at 300 mm / min. The average value was taken after multiple tests.

[0100] 2. Determination of electrolyte resistance:

[0101] The samples of the examples and comparative examples were coated with aluminum foil and immersed in electrolyte at 85°C for 4 hours. The experiment was repeated in parallel three times. After the experiment, it was observed whether the inkjet tape peeled off or delaminated.

[0102] 3. QR code recognition test:

[0103] Ten samples each from the examples and comparative examples were taken for QR code recognition testing to determine whether the samples could be easily scanned and recognized. Recognizing 20 codes was considered fast, recognizing 10 codes was considered relatively fast, and recognizing 5 codes was considered relatively slow.

[0104] The test results are shown in Table 1.

[0105] Table 1

[0106]

Claims

1. A coding tape for power batteries, characterized in that, The inkjet tape comprises, from top to bottom, a pressure-sensitive adhesive layer, an ink layer, a substrate layer, and a release layer; the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive, and the ink layer is a UV-curable ink.

2. The inkjet printing tape for power batteries according to claim 1, characterized in that, By weight, the raw materials for preparing the UV-curable ink include 1-3 parts of dispersant, 0.4-2.2 parts of surfactant, 18-28 parts of UV oligomer, 55-85 parts of UV monomer, 5-15 parts of photoinitiator, 0.2-2.2 parts of light stabilizer, 0.2-2.2 parts of heat stabilizer, and 2-5 parts of carbon black.

3. The inkjet printing tape for power batteries according to claim 1, characterized in that, The UV oligomer is a polysiloxane acrylate, and the UV monomer is an epoxy acrylate monomer.

4. The inkjet printing tape for power batteries according to claim 1, characterized in that, By weight, the raw materials for preparing the acrylate pressure-sensitive adhesive include 34-91 parts of acrylic monomer, 0.1-1 parts of initiator, 3-10 parts of curing agent, 4-6 parts of color paste, and also include solvent I, solvent II, and solvent III.

5. The ink-jet tape for power cells according to claim 4, wherein By weight, the acrylic monomers include 1-3 parts acrylic acid, 1-3 parts hydroxypropyl acrylate, 1-10 parts isobornyl acrylate, 1-5 parts glycidyl methacrylate, 25-45 parts isooctyl acrylate, 1-5 parts lauryl methacrylate, 1-5 parts cyclohexyl acrylate, 1-5 parts cyclopentyl acrylate, 1-5 parts cyclohexyl methyl acrylate, and 1-5 parts dicyclopentadienyl acrylate.

6. The ink-jet tape for power cells according to claim 4, wherein The curing agent is selected from at least one of isocyanate curing agents, maleic anhydride curing agents, and melamine-formaldehyde resin.

7. A method for preparing inkjet printing tape for power batteries according to any one of claims 1-6, characterized in that, Includes the following steps: S1 is used to prepare an acrylic pressure-sensitive adhesive for later use; S2 is used to prepare UV-curable ink for later use; S3 involves spraying UV-curable ink onto a substrate layer, followed by UV curing at a light intensity of 100-120 mW / cm². 2 ; S4 provides a release layer on the side of the substrate layer away from the ink layer; S5 involves extruding and coating an acrylic pressure-sensitive adhesive over the cured ink layer; After curing with S6, the tape is wound up to obtain a semi-finished product.

8. The method for preparing the inkjet printing tape for power batteries according to claim 7, characterized in that, The preparation method of the acrylic pressure-sensitive adhesive in step S1 is as follows: M1 mixes acrylic monomers, introduces nitrogen gas, heats to 50-70°C under nitrogen protection, stirs slowly for 5-7 hours, then adds initiator, and continues the reaction for 4-6 hours to obtain a pre-reacted colloid. M2 is added to solvent I to dilute and stir the pre-reacted colloid. During stirring, the curing agent is added and mixed evenly. Then, the color paste is added and stirred evenly to obtain the pre-cured colloid. Solvents II and III are added to dilute it to a coatable state for later use.

9. The method for preparing the inkjet printing tape for power batteries according to claim 7, characterized in that, The photocuring time in step S3 is 10-50 seconds.

10. The method for preparing the inkjet printing tape for power batteries according to claim 7, characterized in that, In step S5, the coating thickness of the acrylic pressure-sensitive adhesive is 15-50 μm.

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