High-temperature-resistant high-viscosity double-color adhesive tape and preparation method thereof

Abstract

The invention provides a high-temperature-resistant high-viscosity double-color adhesive tape and a preparation method thereof, and the high-temperature-resistant high-viscosity double-color adhesive tape is composed of a base material, a pigment layer, an adhesive combination and a release layer which are connected in sequence, the base material is a polyethylene glycol terephthalate film, the thickness is 12 microns, the surface is subjected to corona treatment, and the surface tension reaches 45 dyn / cm; the pigment layer is arranged on one side of the base material, the thickness of the pigment layer is 0.5-1 mu m, and two-color interval patterns are formed through a printing process; the base material is tightly combined with the adhesive combination and the pigment layer after being subjected to corona treatment, the hydrogenated styrene-butadiene block copolymer and the hydrogenated petroleum resin in the adhesive combination synergistically exert a high-temperature-resistant effect, the molecular structure is stable in a high-temperature environment, and mechanical support of the base material is matched, so that the high-temperature-resistant effect is achieved. The adhesive tape has the effects that in the high-temperature production process of the lithium battery, the viscosity of the adhesive tape is slightly reduced, interlayer separation and structural damage are avoided, and the requirement for long-term use under the high-temperature working condition is met.

Description

Technical Field

[0001] This invention belongs to the field of adhesive tape technology, and particularly relates to a high-temperature resistant, high-adhesion two-color adhesive tape and its preparation method. Background Technology

[0002] The existing two-color tapes have weak bonding between the substrate and the adhesive, and the proportion of high-temperature resistant components in the adhesive is unreasonable. In the high-temperature production environment of lithium batteries, interlayer separation and a significant decrease in adhesion are likely to occur, which cannot meet the requirements of high-temperature processes for tape stability. Traditional two-color adhesive tape lacks key components that can improve initial adhesion and holding power, or the component ratio is inappropriate. After the battery cells are pasted, they are easily displaced by external forces such as vibration and drops, which affects the assembly quality and safety of lithium batteries. Most two-color tapes on the market have poor chemical corrosion resistance in their adhesive and pigment layers. In the lithium battery electrolyte environment, they are prone to swelling and peeling, which not only damages the function of the tape, but may also contaminate the electrolyte and affect the performance of the lithium battery. The printing process used in some two-color tapes has low precision and uneven pigment ratio, resulting in blurry two-color patterns and unclear boundaries. This makes it impossible to clearly display the QR code and makes it difficult to meet the needs of visual inspection and traceability management in the production process. Therefore, a high-temperature resistant, high-adhesion two-color tape and its preparation method are needed to solve the above problems. Summary of the Invention

[0003] The purpose of this invention is to provide a high-temperature resistant, high-adhesion two-color adhesive tape and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature resistant, high-adhesion two-color tape, which is composed of a substrate, a pigment layer, an adhesive combination and a release layer connected in sequence; The substrate is a polyethylene terephthalate film with a thickness of 12μm and a surface treated with corona discharge, resulting in a surface tension of 45dyn / cm. The pigment layer is located on one side of the substrate and has a thickness of 0.5μm to 1μm. It forms a two-color alternating pattern through a printing process and contains 50% carbon black and 50% titanium dioxide. The adhesive assembly is located on the side of the substrate away from the pigment layer and consists of 30% hydrogenated styrene-butadiene block copolymer, 40% hydrogenated petroleum resin, 15% polyisobutylene, 10% terpene resin, 2% pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 3% silica by weight percentage, with a thickness of 20μm to 30μm. The release layer is located on the side of the adhesive assembly away from the substrate and is a 1μm thick poly(N-octadecylurethane) layer; This structural design ensures tight bonding between layers, corona treatment of the substrate enhances interlayer adhesion, the adhesive composition ensures high temperature resistance and tack, and the pigment layer meets the requirements for pattern display. Overall, the tape achieves synergistic multi-performance, which avoids interlayer separation and improves high-temperature stability and functionality.

[0005] Further technical solutions include screen printing or digital inkjet printing. These two processes are highly precise and controllable, allowing for accurate control of ink printing position and amount. The result is that the two-color alternating pattern is neat and clear, avoiding blurry patterns due to process issues, and ensuring the effectiveness of QR code recognition and visual inspection.

[0006] A further technical solution is to use only pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] as an antioxidant in the adhesive composition; This antioxidant has high antioxidant efficiency, and the use of a single antioxidant can avoid compatibility conflicts between different antioxidants. The effect is to effectively inhibit the oxidative aging of adhesives at high temperatures and during long-term use, extend the service life of the tape, and maintain stable adhesion.

[0007] A further technical solution involves using only silica as a filler in the adhesive composition; Silica can enhance the mechanical strength of adhesives without affecting their tackiness or high-temperature resistance. Using it as a single filler can simplify the preparation process, ensure uniform adhesive composition, and improve the adhesive's resistance to deformation, thus preventing adhesive failure due to adhesive deformation during tape use.

[0008] A further technical solution involves using only poly(N-octadecylaminocarbamate) as a non-silicone release agent in the release layer; This release agent has good compatibility with adhesives, poses no risk of silicon migration, and effectively protects the adhesive's stickiness while preventing silicon migration and contamination of the lithium battery, thus ensuring the performance and safety of electronic devices. It can also be easily peeled off during use.

[0009] A further technical solution involves a two-color alternating pattern formed by a printing process in the pigment layer, where the black area is composed of carbon black and the white area is composed of titanium dioxide. By clearly defining the pigment distribution method and combining it with a specific pigment ratio, the effect is to make the pattern colors more contrasting, further improve the clarity of the pattern, and ensure that the cell connection area can be quickly identified during visual inspection, making the QR code display easier to read.

[0010] A method for preparing a high-temperature resistant, high-adhesion two-color adhesive tape, applicable to any of the above-mentioned high-temperature resistant, high-adhesion two-color adhesive tapes, includes the following steps: S1. Substrate preparation: Select a 12μm thick polyethylene terephthalate film and corona treat it until the surface tension is 45dyn / cm. S2. Pigment layer preparation: Carbon black and titanium dioxide are mixed with polyester acrylate ink to prepare black and white ink, which are then alternately printed on one side of the substrate and dried at 80°C for 3 minutes to form a pigment layer with a thickness of 0.5μm to 1μm. S3. Adhesive preparation: Mix the adhesive components in proportion, stir evenly at 120°C, apply to the other side of the substrate with a scraper to a thickness of 20μm~30μm, and dry at 100°C for 5 minutes to cure. S4. Preparation of release layer: Coat the adhesive surface with a 1μm thick layer of poly(N-octadecylaminocarbamate) and cure at 60℃ for 2 minutes; S5. Finished product preparation, cutting and winding; Step-by-step preparation allows for precise control of the formation process of each layer, ensuring stable quality of each batch of tape, meeting the performance standards of each layer, achieving large-scale and standardized production, and avoiding product performance differences caused by fluctuations in preparation parameters.

[0011] In a further technical solution, the printing process in step S2 is either screen printing or digital inkjet printing. During printing, the amount of black and white ink is controlled so that the mass ratio of carbon black and titanium dioxide in the pigment layer is 50%. By combining high-precision printing technology, the uniformity of color and clear boundaries of the two-color interval pattern are further ensured, fully meeting the functional requirements of visual inspection and QR code recognition.

[0012] Compared with the prior art, the beneficial effects of the present invention are: In this invention, the substrate is corona-treated and then tightly bonded to the adhesive and pigment layers. The hydrogenated styrene-butadiene block copolymer and hydrogenated petroleum resin in the adhesive combination work together to provide high-temperature resistance. The molecular structure is stable at high temperatures. Combined with the mechanical support of the substrate, the tape can maintain good adhesion and structural integrity. As a result, the tape adhesion decreases little during the high-temperature production process of lithium batteries, with no interlayer separation or structural damage, meeting the requirements for long-term use under high-temperature conditions. In this invention, polyisobutylene and terpene resin are added in a specific ratio to the adhesive combination. The two work synergistically to enhance the initial tack and holding power of the tape. When the tape is attached to the battery cell, it can firmly adhere to the surface of the battery cell. Under the action of external force, the adhesive can buffer the impact force and maintain the bonding stability. The effect is to effectively prevent the battery cell from shifting when it vibrates or falls, ensure the quality of lithium battery assembly, and reduce the risk of failure caused by battery cell displacement. In this invention, all components of the adhesive combination and pigment layer materials have good chemical corrosion resistance. The non-silicone release agent of the release layer has good compatibility with other layers. In the electrolyte environment, the molecules of each layer material are not easy to react with the electrolyte, and the structure is stable. The effect is that the tape does not swell or fall off, does not contaminate the electrolyte, and the pigment layer pattern remains clear. This maintains the stability of the tape function and ensures the performance and safety of the lithium battery.

[0013] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall process of the present invention; Figure 3 A schematic diagram of the process for preparing the substrate of the present invention; Figure 4 This is a schematic diagram of the process for preparing the pigment layer of the present invention; Figure 5 This is a schematic diagram of the process for preparing the adhesive of the present invention; Figure 6 This is a schematic diagram of the process for preparing the release layer of the present invention; Figure 7 This is a schematic diagram of the process for preparing the finished product of this invention.

[0015] In the diagram: 1. Substrate; 2. Pigment layer; 3. Adhesive assembly; 4. Release layer. Detailed Implementation

[0016] The present invention will be further described below with reference to embodiments.

[0017] The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of protection of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.

[0018] Example 1 like Figures 1-7 As shown, this embodiment of the invention provides a high-temperature resistant, high-adhesion two-color tape, including... The substrate 1, pigment layer 2, adhesive assembly 3, and release layer 4 are connected sequentially. The substrate 1 is a polyethylene terephthalate film with a thickness of 12 μm and its surface is corona treated to achieve a surface tension of 45 dyn / cm. The pigment layer 2 is located on one side of the substrate 1 and has a thickness of 0.8 μm. It is formed by screen printing to create a two-color alternating pattern. Carbon black and titanium dioxide each account for 50% of the total mass of the pigment layer. The adhesive assembly 3 is located on the other side of the substrate 1 away from the pigment layer 2 and consists of 30% hydrogenated styrene-butadiene block copolymer, 40% hydrogenated petroleum resin, 15% polyisobutylene, 10% terpene resin, 2% pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 3% silica by mass percentage, with a thickness of 25 μm. The release layer 4 is located on the side of the adhesive assembly 3 away from the substrate 1 and is a 1 μm thick poly(N-octadecylaminocarbamate) layer.

[0019] In this embodiment, the preparation process strictly follows these steps: S1. Preparation of substrate 1: A 12μm thick polyethylene terephthalate film is selected, and its surface is treated with a corona treatment device, with real-time monitoring of surface tension until it reaches 45 dyn / cm; S2. Preparation of pigment layer 2: Carbon black and polyester acrylate ink are mixed at a mass ratio of 1:1 to obtain black ink, and titanium dioxide and polyester acrylate ink are mixed at a mass ratio of 1:1 to obtain white ink. The black and white inks are alternately printed on one side of substrate 1 using a screen printing device. After printing, substrate 1 is placed in an 80°C drying oven for 3 minutes to form a 0.8μm thick pigment layer 2; S3. Preparation of adhesive combination 3: Each component is weighed according to the above mass percentages, placed in a mixing tank, and stirred at 120°C and 300r / min for 30 minutes until uniform. The adhesive combination 3 is then coated on the other side of substrate 1 away from pigment layer 2 using a doctor blade coater. The coating thickness was controlled at 25μm, and then the substrate 1 was placed in a drying oven at 100℃ for 5 minutes to cure the adhesive combination 3. In step S4, the release layer 4 was prepared by coating the cured adhesive combination 3 with poly(N-octadecylaminocarbamate) using a coating machine, controlling the coating thickness to 1μm. After coating, it was placed in a curing oven at 60℃ for 2 minutes to form the release layer 4. In step S5, the finished product was prepared by cutting the semi-finished product, which consisted of substrate 1, pigment layer 2, adhesive combination 3, and release layer 4, into rolls with a width of 50mm and a length of 100m using a cutting machine. These rolls were then wound up to obtain the high-temperature resistant, high-adhesion, two-color tape. The high-temperature performance of the finished product was tested by placing it in a high-temperature environment at 120℃ for 24 hours. After removal, its adhesion was tested, and the results showed that the adhesion decreased by only 4%, and there was no separation between the layers, fully meeting the high-temperature performance requirements of the tape in the high-temperature production process of lithium batteries.

[0020] Example 2 The difference between this embodiment and Embodiment 1 is that: the pigment layer 2 is printed using digital inkjet printing technology and has a thickness of 0.6 μm; the coating thickness of the adhesive combination 3 is 22 μm; and the adhesion and chemical corrosion resistance of the finished product are the key tests.

[0021] In this embodiment, the preparation steps for substrate 1 are the same as in Embodiment 1; during the preparation of pigment layer 2 (S2), a digital inkjet printing device is used to alternately print the prepared black and white inks onto one side of substrate 1 according to a preset two-color interval pattern program. After printing, the ink is dried at 80°C for 3 minutes to form a pigment layer 2 with a thickness of 0.6 μm. This process can more precisely control the amount of ink used, ensuring that the mass ratio of carbon black to titanium dioxide in pigment layer 2 is strictly maintained at 50%; during the preparation of adhesive combination 3 (S3), the doctor blade gap of the doctor blade coating machine is adjusted to control the coating thickness of adhesive combination 3 to 22 μm, and other parameters are the same as in Embodiment 1; preparation of release layer 4 (S4) and finished product (S5) The preparation steps were the same as in Example 1. The finished product of this example was subjected to an adhesion test. It was adhered to the surface of a lithium battery cell and subjected to a vibration test at a frequency of 50Hz, an amplitude of 2mm, and a duration of 2 hours, as well as a free-fall test at a height of 1.5m for a total of 10 times. After the tests, no displacement of the battery cell was observed, indicating that the tape has excellent initial tack and holding power. Simultaneously, the battery cell with the tape adhered was immersed in lithium battery electrolyte and left at room temperature for 72 hours. After removal, no swelling or detachment of the tape was observed, and the adhesive combination 3 maintained good adhesion, proving that the tape has excellent chemical corrosion resistance and can work stably in the lithium battery electrolyte environment.

[0022] Example 3 The difference between this embodiment and Embodiment 1 is that: the thickness of pigment layer 2 is 1μm, the amount of black and white ink is controlled by screen printing process to ensure that the mass ratio of carbon black and titanium dioxide is 50%; the coating thickness of adhesive combination 3 is 28μm; and the finished product is tested for pattern display effect and comprehensive performance.

[0023] In this embodiment, the preparation steps for substrate 1 (S1) remain unchanged; during the preparation of pigment layer 2 (S2), the printing amount of black and white ink is precisely controlled by the ink flow control system of the screen printing equipment to ensure that the mass ratio of carbon black to titanium dioxide in pigment layer 2 is strictly 50%, and a pigment layer 2 with a thickness of 1μm is formed after drying. The two-color alternating pattern of pigment layer 2 has clear boundaries and uniform color; during the preparation of adhesive combination 3 (S3), the coating thickness of adhesive combination 3 is adjusted to 28μm, and other preparation parameters are the same as in Example 1; the preparation steps for release layer 4 (S4) and finished product (S5) are the same as in Example 1; the pattern display effect of the finished product is tested, and the two colors are visible through visual observation. The color-blocked pattern is clearly distinguishable. A QR code scanning device can scan the QR code printed on the pattern with a 100% recognition rate, meeting the needs of visual inspection, maintenance, and production traceability. Simultaneously, comprehensive performance tests were conducted. The tape was placed in a 110℃ environment for 20 hours, and its adhesion decreased by only 7% upon removal. Tensile shear strength was tested using a tensile testing machine, achieving a result of 1.9 MPa. When battery cells with the tape adhered were immersed in electrolyte for 50 hours, the tape showed no abnormalities, and all performance indicators remained stable. This fully demonstrates that the tape possesses excellent overall performance in addition to good pattern display, making it reliable for application in the lithium battery manufacturing field.

[0024] A method for preparing a high-temperature resistant, high-adhesion two-color adhesive tape, applicable to the high-temperature resistant, high-adhesion two-color adhesive tape described in the above embodiments, includes the following steps: S1, Substrate 1 Preparation Stage: Corona treatment changes the surface molecular structure of substrate 1 through high-voltage discharge, generates polar groups, and increases the surface tension to 45 dyn / cm, creating conditions for subsequent layer adhesion. S2, pigment layer 2: When preparing pigment layer 2, polyester acrylate ink is used as a carrier to uniformly disperse carbon black and titanium dioxide. The ink distribution is precisely controlled by screen or digital inkjet printing process through screen or printhead. Drying at 80℃ for 3 minutes quickly removes ink solvent and cures pigment layer 2, while avoiding high temperature damage to substrate 1. In the preparation of S3 and adhesive combination 3, stirring at 120℃ ensures that all components are fully melted and mixed to ensure uniform composition. The thickness of adhesive combination 3 is controlled by the gap between the doctor blade and the substrate. Drying at 100℃ for 5 minutes allows adhesive combination 3 to crosslink and cure, forming a stable structure. S4, release layer 4 preparation, after coating with 1μm thick poly(N-octadecylurethane) and curing at 60℃ for 2 minutes to form a continuous film of release agent, which is tightly bonded to adhesive combination 3; S5. Finished product preparation: the size is adjusted according to the usage requirements, and the roll is convenient for storage and transportation. The entire process ensures the stability of the performance of each layer by precisely controlling the process parameters, and finally produces a high-temperature resistant and high-adhesion two-color tape that meets the requirements.

[0025] Working principle of the invention: The substrate 1, polyethylene terephthalate film, has good mechanical strength. After corona treatment, polar groups are generated on the surface, and the surface tension is increased to 45 dyn / cm, which enhances the intermolecular forces with pigment layer 2 and adhesive combination 3, so as to achieve tight connection between the layers and avoid interlayer separation. In pigment layer 2, carbon black and titanium dioxide form a distinct two-color alternating pattern. The black area facilitates the location of the battery cell connection point, while the white area contrasts with the black area, making the QR code information clearly identifiable and meeting the needs of visual inspection and traceability. In adhesive combination 3, hydrogenated styrene-butadiene block copolymer and hydrogenated petroleum resin maintain molecular stability at high temperature to ensure that the adhesion does not decrease, polyisobutylene and terpene resin enhance initial adhesion and holding adhesion to achieve firm bonding of battery cells, antioxidant inhibits oxidative aging, and silica improves mechanical strength and extends tape life. Release layer 4 (poly(N-octadecylaminocarbamate)) has good compatibility with adhesive combination 3. It is isolated from air and impurities during storage to protect the adhesiveness. It can be easily peeled off during use without affecting the bonding effect between adhesive combination 3 and the battery cell.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature resistant, high-adhesion two-color adhesive tape, characterized in that, It consists of a substrate (1), a pigment layer (2), an adhesive assembly (3), and a release layer (4) connected in sequence; The substrate (1) is a polyethylene terephthalate film with a thickness of 12 μm and a surface treated with corona, with a surface tension of 45 dyn / cm; the pigment layer (2) is located on one side of the substrate (1) with a thickness of 0.5 μm to 1 μm, and forms a two-color alternating pattern through a printing process, containing 50% carbon black and 50% titanium dioxide. The adhesive assembly (3) is disposed on the side of the substrate (1) away from the pigment layer (2), and is composed of 30% hydrogenated styrene-butadiene block copolymer, 40% hydrogenated petroleum resin, 15% polyisobutylene, 10% terpene resin, 2% pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 3% silica by mass percentage, with a thickness of 20μm to 30μm; The release layer (4) is located on the side of the adhesive assembly (3) away from the substrate (1) and is a 1 μm thick poly(N-octadecylaminocarbamate) layer.

2. The high-temperature resistant, high-adhesion, two-color adhesive tape according to claim 1, characterized in that, The printing process is either screen printing or digital inkjet printing.

3. The high-temperature resistant, high-adhesion, two-color adhesive tape according to claim 1, characterized in that, The adhesive combination (3) contains only pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] as an antioxidant.

4. The high-temperature resistant, high-adhesion, two-color adhesive tape according to claim 1, characterized in that, The adhesive combination (3) contains only silica as a filler.

5. The high-temperature resistant, high-adhesion, two-color adhesive tape according to claim 1, characterized in that, The release layer (4) contains only poly(N-octadecylaminocarbamate) as a non-silicone release agent.

6. The high-temperature resistant, high-adhesion, two-color adhesive tape according to claim 1, characterized in that, The pigment layer (2) is a two-color alternating pattern formed by printing process. The black area is composed of carbon black and the white area is composed of titanium dioxide.

7. A method for preparing a high-temperature resistant, high-adhesion two-color adhesive tape, applicable to the high-temperature resistant, high-adhesion two-color adhesive tape according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Substrate (1) preparation: Select a 12μm thick polyethylene terephthalate film and corona treat it until the surface tension is 45dyn / cm. S2, Pigment layer (2) preparation: Carbon black and titanium dioxide are mixed with polyester acrylate ink to make black and white ink, which are then alternately printed on one side of substrate (1) and dried at 80°C for 3 minutes to form a 0.5μm~1μm thick pigment layer (2). S3, preparation of adhesive combination (3): mix the components of adhesive combination (3) in proportion, stir evenly at 120°C, apply to the other side of the substrate with a scraper, 20μm~30μm thick, and dry at 100°C for 5 minutes to cure; S4, release layer (4) preparation: a 1 μm thick poly(N-octadecylaminocarbamate) is coated on the surface of the adhesive assembly (3) and cured at 60°C for 2 minutes; S5. Finished product preparation, cutting and winding.

8. The method for preparing high-temperature resistant, high-adhesion two-color adhesive tape according to claim 7, characterized in that, In step S2, the printing process is either screen printing or digital inkjet printing. During printing, the amount of black and white ink is controlled so that the mass ratio of carbon black and titanium dioxide in the pigment layer (2) is 50%.

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