High-viscosity power-on viscosity-reducing adhesive tape and preparation method thereof

Abstract

The invention relates to the technical field of adhesive tapes, and discloses a high-viscosity power-on viscosity-reducing adhesive tape and a preparation method thereof.The adhesive tape comprises an adhesive layer and release films attached to the two sides of the adhesive layer, the adhesive layer is prepared by adopting acrylate monomers, a carbon nano tube modification functional agent and the like as raw materials through free radical polymerization, and the release films are attached to the two sides of the adhesive layer; wherein the carbon nanotube modified functional agent is prepared by modifying a macromolecular substance with a block connection structure on the surface of a carbon nanotube, and the macromolecular substance contains an alkenyl functional group and can participate in the subsequent polymerization process of an acrylate monomer, so that the carbon nanotube is uniformly dispersed to form a continuous conductive network; compared with the prior art, the high-temperature-resistant adhesive has the advantages that the high-temperature-resistant performance of the adhesive can be improved, electrifying viscosity reduction of the adhesive is facilitated, the macromolecular substance can serve as a cross-linking agent, cohesive energy of the adhesive is improved, the adhesive performance of the adhesive can be further improved, and in addition, rigid rings and a large number of ether bonds in the structure of the macromolecular substance can effectively enhance the high-temperature-resistant performance and the adhesive performance of the adhesive.

Description

Technical Field

[0001] This invention relates to the field of adhesive tape technology, specifically to a high-viscosity, electrically conductive, anti-adhesive tape and its preparation method. Background Technology

[0002] With the miniaturization of electronic devices, the flexibility of wearable devices, and the modularization of new energy batteries, traditional mechanical disassembly methods can no longer meet the requirements for non-destructive separation of precision components. Against this backdrop, electrically conductive anti-adhesion tape has emerged and is gradually becoming a representative of smart adhesive materials. As the name suggests, electrically conductive anti-adhesion tape refers to tape that, by applying voltage, can guide the polar molecules in the adhesive to rearrange, thereby reducing the adhesion between the tape and the adhered object. This gives the tape the ability to be easily peeled off without the need for ultraviolet radiation or high-temperature heating, thus allowing the tape to be easily removed from the equipment without causing damage and offering high economic benefits.

[0003] Existing conductive adhesive tapes generally require the addition of inorganic conductive fillers to impart good conductivity and achieve the effect of reducing tack through electrical conduction. However, there is a natural interface problem between inorganic conductive fillers and adhesives, which not only affects the conductivity of the adhesive, leading to incomplete peeling, but also causes adhesive residue on the equipment. In addition, existing conductive tapes have poor adhesion performance, making it difficult to meet the working requirements of high-tack conductive tapes. Therefore, it is of great significance to provide a conductive tape with excellent comprehensive performance. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high-viscosity, electrically conductive, anti-adhesive tape and its preparation method.

[0005] (II) Technical Solution A high-adhesion, electrically conductive, non-adhesive tape includes an adhesive layer and release films attached to both sides of the adhesive layer; The adhesive layer is made from the following raw materials measured in parts by weight: 40-60 parts of acrylate functional monomers; 5-15 parts of acrylic functional monomers; 1-3 parts of ionic liquid monomer; 1-4 parts of carbon nanotube modifying functional agent; Initiator 0.5-1.5 parts; Lithium salt 0.5-1 part; 50-80 parts organic solvent; 2-4 parts thickener.

[0006] As a further embodiment of the present invention, the acrylate functional monomer is at least one of methyl methacrylate, butyl acrylate, isooctyl acrylate, or methyl acrylate; the acrylic functional monomer is methacrylic acid or acrylic acid; the ionic liquid monomer is 1-vinyl-3-methylimidazolium dinitrile or 1-allyl-3-vinylimidazolium dinitrile; the initiator is azobisisobutyronitrile or azobisisoheptanenitrile; the lithium salt is any one of lithium itaconic acid, lithium tetrafluoroborate, or lithium bis(oxalato)borate; the organic solvent is ethyl acetate; and the tackifier is hydrogenated rosin ester or pentaerythritol rosin ester.

[0007] As a further aspect of the present invention, the carbon nanotube modified functional agent is prepared by the following method: Step 1: Add acidified carbon nanotubes to toluene, control the ultrasonic frequency at 100-120kHz, and ultrasonically disperse for 1-2 hours. Then, add 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride to the formed uniform dispersion. After the addition is complete, start stirring and mix evenly. Then, raise the temperature to 30-40℃ and add the catalyst at the same time. After the addition is complete, continue to keep warm and stir for 2-4 hours to form an intermediate material. Step 2: Add the functional binder to the intermediate material. After the addition is complete, continue stirring for 8-16 hours, stop heating, centrifuge to remove the solid material, and then wash and vacuum dry it to obtain the carbon nanotube modified functional agent.

[0008] As a further aspect of the present invention, the acidified carbon nanotubes are prepared by the following method: Carbon nanotubes are added to a 1:1 mixture of concentrated hydrochloric acid and concentrated nitric acid by volume. After addition, the mixture is dispersed evenly. The temperature is then raised to 60-70℃ and stirred continuously for 2-4 hours. The mixture is then cooled and discharged. The solid material is centrifuged, washed until neutral, and then vacuum dried.

[0009] As a further embodiment of the present invention, the mass ratio of the acidified carbon nanotubes, 9,9-bis(3,4-dicarboxyphenyl)fluorene dihydric anhydride and the functional linker is 1:1.5-3:1-2.

[0010] As a further embodiment of the present invention, the catalyst is pyridine or triethylamine.

[0011] As a further aspect of the present invention, the functional binder is prepared by the following method: The di-terminated amine was added to 1,4-dioxane and stirred until a homogeneous reaction solution was formed. Then, the glycidyl compound was added to the reaction solution. After the addition was complete, the temperature was raised to 60-70°C and stirred continuously for 3-6 hours. The solvent was then evaporated and removed. The product was purified to obtain the functional linker.

[0012] As a further embodiment of the present invention, the dual-terminated amination is any one of 3,6,9-trioxaundecan-1,11-diamine, 2,2'-oxobis(ethylamine), or 1,8-diamino-3,6-dioxaoctane; the glycidyl compound is glycidyl methacrylate or glycidyl acrylate.

[0013] As a further aspect of the present invention, the molar ratio of the di-terminated amination to the glycidyl compound is 1:2.

[0014] In the above technical solution, carbon nanotubes are first acidified using a mixed acid solution of concentrated hydrochloric acid and concentrated nitric acid to expose a large number of active hydroxyl groups on their surface. Then, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride is used as a modifier and undergoes ring-opening esterification with the active hydroxyl groups of the acidified carbon nanotubes under the action of a catalyst. The remaining amount of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in the system can further undergo ring-opening esterification with the active hydroxyl groups in the structure of the functional linker. This forms a system in which the hydroxyl groups on the surface of the carbon nanotubes serve as active initiation sites, initiating in-situ graft polymerization of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride and the functional linker on the carbon nanotubes. This modifies the surface of the carbon nanotubes with a block linkage structure, thus obtaining a carbon nanotube modified functional agent.

[0015] The functional linker is made from di-terminal amines and glycidyl compounds. The amino substituents in their structures can undergo ring-opening addition with the epoxy substituents. By controlling the ratio of the two, a functional linker with unsaturated alkenyl functional groups at the ends of the structure and containing two equivalent hydroxyl substituents generated by the ring-opening reaction can be obtained.

[0016] A method for preparing a high-viscosity, electrically conductive, anti-adhesive tape includes the following steps: Step 1: Add acrylate functional monomers, acrylic functional monomers, ionic liquid monomers, carbon nanotube modifiers, lithium salts and tackifiers to an organic solvent. After addition, start stirring and mix evenly. Then, raise the temperature to 40-50℃ and stir for 1-2 hours. Add the initiator and raise the temperature to 70-80℃. Continue stirring for 4-8 hours. Then, stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it in a temperature of 70-80℃ for 3-5 minutes to form an adhesive layer. Then, cover the coated surface with another layer of release film.

[0017] (iii) Beneficial technical effects This invention prepares carbon nanotube modified functional agents by modifying the surface of carbon nanotubes with macromolecular substances having block linkage structures. It should be noted that the macromolecular structure contains a large number of unsaturated alkenyl functional groups, which can participate in the subsequent polymerization process of acrylate monomers under the action of an initiator. On the one hand, this linkage mode greatly improves the interfacial properties between carbon nanotubes and the acrylate adhesive polymer, promoting the uniform dispersion and arrangement of carbon nanotubes to form a continuous conductive network, which is beneficial for achieving electrostatic reduction and adhesion of the adhesive. On the other hand, the presence of a large number of unsaturated alkenyl functional groups allows the carbon nanotubes to act as crosslinking agents, significantly increasing the crosslinking density of the adhesive molecular chains, effectively improving the cohesive energy of the adhesive, and thus improving the adhesive properties. In addition, the rigid rings and numerous ether bonds in the macromolecular structure can effectively enhance the high-temperature resistance and adhesive properties of the adhesive, respectively. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be provided below. Preferred embodiments of the invention are given below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0019] Preparation Example Preparation of carbon nanotube modified functional agents: Step A: Add 1.2g of carbon nanotubes to 150mL of a mixed solution of concentrated hydrochloric acid and concentrated nitric acid with a volume ratio of 1:1. After the addition is complete, disperse evenly, then raise the temperature to 65℃ and stir continuously for 3h. After cooling, discharge the material, centrifuge to remove the solid material, wash until neutral, and then vacuum dry to obtain acidified carbon nanotubes. Step B: Add 1g of acidified carbon nanotubes to toluene, control the ultrasonic frequency at 100kHz, and ultrasonically disperse for 1h. Then add 2.6g of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride to the formed uniform dispersion. After the addition is complete, start stirring and mix evenly. Then raise the temperature to 35℃ and add 0.1g of pyridine. After the addition is complete, continue to keep warm and stir for 3h to form an intermediate material. Step C: Add 2g of functional binder to the intermediate material. After adding, continue stirring for 12 hours, stop heating, centrifuge to remove the solid material, and then wash and vacuum dry it to obtain the carbon nanotube modified functional agent.

[0020] The functional binder is prepared using the following method: 0.8 g of 3,6,9-trioxaundecan-1,11-diamine was added to 1,4-dioxane and stirred until a homogeneous reaction solution was formed. Then, 1.2 g of glycidyl methacrylate was added to the reaction solution. After the addition was complete, the temperature was raised to 65°C and stirred continuously at this temperature for 4 hours. The solvent was then evaporated to remove the solvent. The product was purified to obtain a functional linker.

[0021] Example 1:

[0022] A high-adhesion, electrically conductive, non-sticky adhesive tape includes an adhesive layer and release films adhered to both sides of the adhesive layer; the adhesive layer is made from the following raw materials measured in parts by weight: 40 parts of methyl methacrylate; 5 parts methacrylic acid; 1 part of 1-vinyl-3-methylimidazolium dinitrile ammonium salt; One part of carbon nanotube modifying functional agent; 0.5 parts of azobisisobutyronitrile; 0.5 parts of lithium tetrafluoroborate; 50 parts of ethyl acetate; Two parts of hydrogenated rosin ester.

[0023] The method for preparing the adhesive tape includes the following steps: Step 1: Add methyl methacrylate, methacrylic acid, 1-vinyl-3-methylimidazolium dinitrile, carbon nanotube modifier, lithium tetrafluoroborate and hydrogenated rosin ester to ethyl acetate. After the addition is complete, start stirring. After mixing evenly, raise the temperature to 40°C and stir for 2 hours. Then add azobisisobutyronitrile and raise the temperature to 70°C. Continue stirring for 8 hours. Then stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at 75°C for 4 minutes to form an adhesive layer. Finally, cover the coated surface with another layer of release film.

[0024] The preparation method of the carbon nanotube modified functional agent is shown in the preparation example, and the same applies to the following.

[0025] Example 2:

[0026] A high-adhesion, electrically conductive, non-sticky adhesive tape includes an adhesive layer and release films adhered to both sides of the adhesive layer; the adhesive layer is made from the following raw materials measured in parts by weight: 45 parts of methyl methacrylate; 6 parts methacrylic acid; 2 parts of 1-vinyl-3-methylimidazolium dinitrile ammonium salt; Three parts of carbon nanotube modifying functional agent; 1 part of azobisisobutyronitrile; 0.8 parts of lithium tetrafluoroborate; 60 parts of ethyl acetate; Three parts of hydrogenated rosin ester.

[0027] The method for preparing the adhesive tape includes the following steps: Step 1: Add methyl methacrylate, methacrylic acid, 1-vinyl-3-methylimidazolium dinitrile, carbon nanotube modifier, lithium tetrafluoroborate, and hydrogenated rosin ester to ethyl acetate. After the addition is complete, start stirring and mix evenly. Then raise the temperature to 45°C and stir for 2 hours. Add azobisisobutyronitrile and raise the temperature to 75°C. Continue stirring for 6 hours. Then stop heating, cool down, and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at 75°C for 4 minutes to form an adhesive layer. Finally, cover the coated surface with another layer of release film.

[0028] Example 3:

[0029] A high-adhesion, electrically conductive, non-sticky adhesive tape includes an adhesive layer and release films adhered to both sides of the adhesive layer; the adhesive layer is made from the following raw materials measured in parts by weight: 60 parts of methyl methacrylate; 15 parts methacrylic acid; 3 parts of 1-vinyl-3-methylimidazolium dinitrile ammonium salt; Four parts of carbon nanotube modifying functional agent; 1.5 parts of azobisisobutyronitrile; One part of lithium tetrafluoroborate; 80 parts of ethyl acetate; 4 parts of hydrogenated rosin ester.

[0030] The method for preparing the adhesive tape includes the following steps: Step 1: Add methyl methacrylate, methacrylic acid, 1-vinyl-3-methylimidazolium dinitrile, carbon nanotube modifier, lithium tetrafluoroborate and hydrogenated rosin ester to ethyl acetate. After the addition is complete, start stirring and mix evenly. Then raise the temperature to 50°C and stir for 1 hour. Add azobisisobutyronitrile and raise the temperature to 80°C. Continue stirring for 4 hours. Then stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at 80°C for 3 minutes to form an adhesive layer. Finally, cover the coated surface with another layer of release film.

[0031] Comparative Example 1 A high-adhesion, electrically conductive, non-sticky adhesive tape includes an adhesive layer and release films adhered to both sides of the adhesive layer; the adhesive layer is made from the following raw materials measured in parts by weight: 45 parts of methyl methacrylate; 6 parts methacrylic acid; 2 parts of 1-vinyl-3-methylimidazolium dinitrile ammonium salt; Three parts of carbon nanotubes; 1 part of azobisisobutyronitrile; 0.8 parts of lithium tetrafluoroborate; 60 parts of ethyl acetate; Three parts of hydrogenated rosin ester.

[0032] The method for preparing the adhesive tape includes the following steps: Step 1: Add methyl methacrylate, methacrylic acid, 1-vinyl-3-methylimidazolium dinitrile, carbon nanotubes, lithium tetrafluoroborate and hydrogenated rosin ester to ethyl acetate. After the addition is complete, start stirring and mix evenly. Then raise the temperature to 45°C and stir for 2 hours. Add azobisisobutyronitrile and raise the temperature to 75°C. Continue stirring for 6 hours. Then stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at 75°C for 4 minutes to form an adhesive layer. Finally, cover the coated surface with another layer of release film.

[0033] Comparative Example 2 A high-adhesion, electrically conductive, non-sticky adhesive tape includes an adhesive layer and release films adhered to both sides of the adhesive layer; the adhesive layer is made from the following raw materials measured in parts by weight: 45 parts of methyl methacrylate; 6 parts methacrylic acid; 2 parts of 1-vinyl-3-methylimidazolium dinitrile ammonium salt; 1 part of azobisisobutyronitrile; 0.8 parts of lithium tetrafluoroborate; 60 parts of ethyl acetate; Three parts of hydrogenated rosin ester.

[0034] The method for preparing the adhesive tape includes the following steps: Step 1: Add methyl methacrylate, methacrylic acid, 1-vinyl-3-methylimidazolium dinitrile, lithium tetrafluoroborate and hydrogenated rosin ester to ethyl acetate. After the addition is complete, start stirring and mix evenly. Then raise the temperature to 45°C and stir for 2 hours. Add azobisisobutyronitrile and raise the temperature to 75°C. Continue stirring for 6 hours. Then stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at 75°C for 4 minutes to form an adhesive layer. Finally, cover the coated surface with another layer of release film.

[0035] Test case According to standard GB / T 2792-2014, the peel force of the tapes in the examples and comparative examples was tested. The same batch of samples were energized with 30V voltage for 1 minute and the peel force was tested to evaluate the energized anti-adhesion effect of the tapes. Apply the tape to a clean glass plate surface and place it in a 100°C environment. After 24 hours, remove the tape, peel off the adhesive film, observe the residual adhesive, and evaluate the high-temperature resistance of the tape. Record the test results in the table below:

[0036] Analysis of the test results shows that the tape prepared in the embodiments of the present invention exhibits superior performance in all aspects. After replacing the carbon nanotube modifier with unmodified carbon nanotubes, the problem of carbon nanotube aggregation cannot be solved, making it difficult to construct a stable and continuous conductive pathway in the adhesive. Therefore, the tape's electrostatic anti-adhesion effect is significantly reduced. In addition, due to the loss of macromolecular substances, the cross-linking density of the adhesive molecular chain is reduced, and the rigid rings and a large number of ether bonds are also lost, resulting in a significant decrease in the tape's bonding performance and high-temperature resistance.

[0037] Based on the preferred embodiments of the present invention, and through the above description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A high-adhesion, electrically conductive, anti-adhesive tape, characterized in that, Includes an adhesive layer and release films attached to both sides of the adhesive layer; The adhesive layer is made from the following raw materials measured in parts by weight: 40-60 parts of acrylate functional monomers; 5-15 parts of acrylic functional monomers; 1-3 parts of ionic liquid monomer; 1-4 parts of carbon nanotube modifying functional agent; Initiator 0.5-1.5 parts; Lithium salt 0.5-1 part; 50-80 parts organic solvent; 2-4 parts thickener.

2. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 1, characterized in that, The acrylate functional monomer is at least one of methyl methacrylate, butyl acrylate, isooctyl acrylate, or methyl acrylate; the acrylic functional monomer is methacrylic acid or acrylic acid; the ionic liquid monomer is 1-vinyl-3-methylimidazolium dinitrile or 1-allyl-3-vinylimidazolium dinitrile; the initiator is azobisisobutyronitrile or azobisisoheptanenitrile; the lithium salt is any one of lithium itaconic acid, lithium tetrafluoroborate, or lithium bis(oxalato)borate; the organic solvent is ethyl acetate; and the tackifier is hydrogenated rosin ester or pentaerythritol rosin ester.

3. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 1, characterized in that, The carbon nanotube modified functional agent is prepared by the following method: Step 1: Add acidified carbon nanotubes to toluene, control the ultrasonic frequency at 100-120kHz, and ultrasonically disperse for 1-2 hours. Then, add 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride to the formed uniform dispersion. After the addition is complete, start stirring and mix evenly. Then, raise the temperature to 30-40℃ and add the catalyst at the same time. After the addition is complete, continue to keep warm and stir for 2-4 hours to form an intermediate material. Step 2: Add the functional binder to the intermediate material. After the addition is complete, continue stirring for 8-16 hours, stop heating, centrifuge to remove the solid material, and then wash and vacuum dry it to obtain the carbon nanotube modified functional agent.

4. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 3, characterized in that, The acidified carbon nanotubes were prepared using the following method: Carbon nanotubes are added to a 1:1 mixture of concentrated hydrochloric acid and concentrated nitric acid by volume. After addition, the mixture is dispersed evenly. The temperature is then raised to 60-70℃ and stirred continuously for 2-4 hours. The mixture is then cooled and discharged. The solid material is centrifuged, washed until neutral, and then vacuum dried.

5. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 3, characterized in that, The mass ratio of the acidified carbon nanotubes, 9,9-bis(3,4-dicarboxyphenyl)fluorene dihydric anhydride, and the functional linker is 1:1.5-3:1-2.

6. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 3, characterized in that, The catalyst is pyridine or triethylamine.

7. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 3, characterized in that, The functional binder is prepared using the following method: The di-terminated amine was added to 1,4-dioxane and stirred until a homogeneous reaction solution was formed. Then, the glycidyl compound was added to the reaction solution. After the addition was complete, the temperature was raised to 60-70°C and stirred continuously for 3-6 hours. The solvent was then evaporated and removed. The product was purified to obtain the functional linker.

8. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 7, characterized in that, The dual-terminated amination is any one of 3,6,9-trioxaundecan-1,11-diamine, 2,2'-oxobis(ethylamine), or 1,8-diamino-3,6-dioxaoctane; the glycidyl compound is glycidyl methacrylate or glycidyl acrylate.

9. The high-viscosity, electrically conductive, anti-adhesive tape according to claim 7, characterized in that, The molar ratio of the di-terminated amination to the glycidyl compound is 1:

2.

10. A method for preparing a high-viscosity, electrically conductive, anti-adhesive tape as described in claim 1, characterized in that, Includes the following steps: Step 1: Add acrylate functional monomers, acrylic functional monomers, ionic liquid monomers, carbon nanotube modifiers, lithium salts and tackifiers to an organic solvent. After addition, start stirring and mix evenly. Then, raise the temperature to 40-50℃ and stir for 1-2 hours. Add the initiator and raise the temperature to 70-80℃. Continue stirring for 4-8 hours. Then, stop heating, cool down and discharge the material to form an adhesive mixture. The second step is to apply the adhesive mixture to one side of the release film, then place it at a temperature of 70-80℃ for 3-5 minutes to form an adhesive layer. Then, cover the coated surface with another layer of release film.

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