High-bonding-strength pressure-sensitive adhesive tape with conductivity and preparation method of high-bonding-strength pressure-sensitive adhesive tape
By using materials such as acrylate monomers and conductive fillers, pressure-sensitive tapes with high conductivity and high bonding strength are prepared, which solves the problem of degradation in the performance of existing voltage-sensitive tapes in long-term use, and simplifies the preparation process and reduces the use of organic solvents.
Patent Information
- Application Number
- CN202411873195.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2025-04-01
AI Technical Summary
In long-term use, existing voltage-sensitive tapes are susceptible to ambient temperature and humidity, and their conductivity and adhesion properties are degraded. At the same time, the preparation of organic solvents with complex processes and the use of used causes pollution to the environment.
Materials such as acrylate monomers, initiators and conductive fillers are used to apply onto a polyimide film with radiation resistance through uniform mixing and coating machine, and pressure-sensitive tape with high conductivity and adhesive strength is prepared after drying.
The conductivity and bonding strength of the voltage-sensitive adhesive tape are improved, the volume resistivity is reduced to 9.10Ω·cm, and the bonding strength can reach 1.17N/mm, which is about 220% and 234% higher than the prior art. At the same time, the preparation process is simplified and the organic solvents used are reduced.
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Figure CN119736032A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of polymer materials, and in particular relates to a high-bonding-strength pressure-sensitive adhesive tape with conductive properties and a preparation method thereof. Background Art
[0002] Pressure-sensitive adhesives are pressure-sensitive adhesives, commonly known as self-adhesives, or pressure-sensitive adhesives for short. Pressure-sensitive adhesive products include three categories: pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, and pressure-sensitive films. Pressure-sensitive adhesives have high pressure sensitivity, and applying pressure to them can immediately achieve the purpose of bonding any smooth surface of the adherend.
[0003] Pressure-sensitive adhesive is a polymer adhesive material used to connect the glass secondary surface mirror of a spacecraft to the spacecraft structure and prevent static electricity accumulation on the surface. Therefore, the material is required to have certain bonding strength and conductive properties and is a functional adhesive material.
[0004] The prior art fully mixes conductive fillers such as metal powder, glass beads with metal plating on the surface, or conductive carbon black with the base material of the pressure-sensitive adhesive to give the tape conductive properties; or uses a substrate with conductive properties, such as conductive metal foil, conductive fiber cloth, conductive foam, etc., and then coats the surface with pressure-sensitive adhesive to make a conductive pressure-sensitive tape.
[0005] Existing conductive pressure-sensitive tapes are easily affected by ambient temperature and humidity. During long-term use, the conductive and adhesive properties of the tapes will decrease. At the same time, the preparation process is complicated and the organic solvents used in the preparation process will cause environmental pollution.
[0006] The volume resistivity of conductive adhesives on the market is generally above 20Ω·cm, and the viscosity can reach about 0.5N / mm under normal conditions. Summary of the invention
[0007] In order to improve the conductivity and viscosity of the conductive tape so that the conductive tape can be used in spacecraft, the present invention proposes a high-adhesion strength pressure-sensitive tape with conductive properties and a preparation method thereof, which is used for conducting the glass-type secondary surface mirror of the spacecraft with the spacecraft structure and preventing surface static electricity accumulation.
[0008] The method for preparing the high-adhesive-strength pressure-sensitive adhesive tape with conductive properties comprises the following steps:
[0009] Step 1, after dissolving the acrylate monomer, adding an initiator into the solution to prepare a pressure-sensitive adhesive resin;
[0010] The specific preparation process is:
[0011] (1) adding an acrylate monomer to a solvent and uniformly mixing the mixture at room temperature;
[0012] The acrylic acid ester monomer is at least one selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, acrylic acid, acrylonitrile, isooctyl methacrylate, and methacrylamide;
[0013] The type and amount of the acrylic ester monomer are selected according to the required performance of the pressure-sensitive adhesive, and are composed of three types of monomers, namely soft monomers, hard monomers and functional monomers; the soft monomers are alkyl acrylates and alkyl methacrylates with carbon atoms of 4-18, so that the pressure-sensitive adhesive has good initial adhesion; the hard monomers are monomers with a high homopolymer glass transition temperature, which increase the rigidity of the polymer molecular chain and produce polymers with good cohesion and tensile strength; the functional monomers are acrylic monomers containing active groups such as hydroxyl groups or amides, which can provide cohesion and play a role in modification, while improving the adhesion performance of the pressure-sensitive adhesive.
[0014] The solvent is ethyl acetate, cyclohexane, N,N-dimethylformamide or acetone, preferably N,N-dimethylformamide, more preferably ethyl acetate;
[0015] (2) adding the initiator to the mixed solvent and uniformly mixing the mixture, and removing oxygen under nitrogen conditions;
[0016] The initiator is one of dibenzoyl peroxide, azobisisobutyronitrile, tert-butyl hydroperoxide, dilauroyl peroxide or tert-butyl peroxyformate, preferably azobisisobutyronitrile, more preferably dibenzoyl peroxide;
[0017] (3) increasing the temperature to cause the initiator to crack and initiate polymerization of the acrylate monomer;
[0018] The temperature is 80°C and the reaction time is 2h;
[0019] In the above preparation process, based on 100 parts by weight of the pressure-sensitive adhesive resin, the amount of the initiator is preferably 1.2-0.5 parts by weight, more preferably 0.5-0.8 parts by weight; the content of the hard monomer is preferably 10-35 parts by weight, more preferably 20-35 parts by weight; the content of the soft monomer is preferably 20-50 parts by weight, more preferably 25-40 parts by weight; the content of the functional monomer is preferably 20-40 parts by weight, more preferably 20-30 parts by weight.
[0020] Step 2, mixing the pressure-sensitive adhesive resin and the conductive filler evenly to obtain a mixed adhesive solution;
[0021] The mass ratio of the pressure-sensitive adhesive resin to the conductive filler is 1:0.04-0.1;
[0022] The conductive filler is selected from at least one of conductive carbon black, hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, graphene oxide, and reduced graphene oxide, preferably selected from carboxylated multi-walled carbon nanotubes, and more preferably selected from conductive carbon black.
[0023] Step 3, using a coating machine to evenly coat the mixed adhesive on the substrate to obtain a sample to be dried;
[0024] The substrate is selected from a polyimide film having radiation resistance.
[0025] Step 4: Transfer the sample to be dried to a blast oven for drying, and the pressure-sensitive tape can be obtained after the adhesive solution is cured into a film.
[0026] The drying temperature is preferably 75-100°C, more preferably 80-90°C;
[0027] The prepared conductive pressure-sensitive adhesive tape comprises a base layer and a colloid layer. The base layer is a polyimide film with a thickness of 25 microns; the colloid layer is a conductive pressure-sensitive material with a thickness of 100 microns.
[0028] The conductive pressure-sensitive adhesive tape prepared by the present invention has an optimal volume resistivity of 9.10Ω·cm and a bonding strength of up to 1.17N / mm. Compared with existing ones, the volume resistivity and bonding strength are increased by about 220% and 234% respectively.
[0029] Conductive pressure sensitive tape is used for the conduction between the glass secondary surface mirror and the spacecraft structure.
[0030] The advantages and beneficial effects of the present invention are:
[0031] (1) The preparation method of the present invention uses fewer raw materials and has a simple synthesis process;
[0032] (2) The conductive pressure-sensitive adhesive tape of the present invention has good conductivity and adhesion properties;
[0033] (3) The conductive pressure-sensitive adhesive tape of the present invention is used in spacecraft and can still maintain good adhesion performance after long-term irradiation. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is a physical picture of the conductive pressure-sensitive adhesive tape prepared in Example 2 of the present invention;
[0035] Figure 2 This is the peeling test curve of the conductive pressure-sensitive adhesive tape of Comparative Example 1;
[0036] Figure 3 This is the peeling test curve of the conductive pressure-sensitive adhesive tape of Example 1;
[0037] Figure 4This is the peeling test curve of the conductive pressure-sensitive adhesive tape of Example 2;
[0038] Figure 5 This is the peeling test curve of the conductive pressure-sensitive adhesive tape of Example 3. DETAILED DESCRIPTION
[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0040] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.
[0041] The sources of the compounds used in the examples are as follows:
[0042] Benzoyl peroxide, methyl methacrylate, 2-ethylhexyl acrylate, isooctyl methacrylate, and hydroxyethyl methacrylate were from Shanghai MacLean Biochemical Technology Co., Ltd. (China); ethyl acetate was from Hebei Bailingwei Ultrafine Materials Co., Ltd. (China).
[0043] The test instruments and test conditions used in the examples are as follows:
[0044] Peel test machine: The model of the peel test machine is KJ-1065A, and the test method is carried out in accordance with GB / T 2792-2014.
[0045] Conductivity test: Four-probe tester RTS-8.
[0046] Comparative Example 1
[0047] Methyl methacrylate, 2-ethylhexyl acrylate and isooctyl methacrylate were mixed in a weight ratio of 2.0:4.0:4.0, and 0.6wt% of dibenzoyl peroxide was added as an initiator, and 150wt% of ethyl acetate was added as a solvent. The mixture was stirred evenly and reacted at 80°C for 2 hours. Then the glue was mixed evenly with 5wt% of conductive carbon black, coated on a polyimide film, and the film was moved to an 80°C oven and heated until the solvent evaporated.
[0048] The pressure-sensitive tape was subjected to peeling performance tests and conductivity tests, and the peeling strength was measured to be 0.972 N / mm and the volume resistivity was 19.6 Ω·cm.
[0049] Example 1
[0050] Methyl methacrylate, 2-ethylhexyl acrylate and isooctyl methacrylate were mixed in a weight ratio of 2.5:4.0:3.5, and 0.6wt% of dibenzoyl peroxide was added as an initiator, and 150wt% of ethyl acetate was added as a solvent. The mixture was stirred evenly and reacted at 80°C for 2 hours. Then the glue was mixed evenly with 5wt% of conductive carbon black, coated on a polyimide film, and the film was moved to an 80°C oven and heated until the solvent evaporated.
[0051] The pressure-sensitive tape was subjected to peeling performance tests and conductivity tests, and the peeling strength was measured to be 1.289 N / mm and the volume resistivity was 21.2 Ω·cm.
[0052] Example 2
[0053] Methyl methacrylate, 2-ethylhexyl acrylate and isooctyl methacrylate were mixed in a weight ratio of 2.0:4.5:3.5, and 0.6wt% of dibenzoyl peroxide was added as an initiator and 150wt% of ethyl acetate was added as a solvent. The mixture was stirred evenly and reacted at 80°C for 2 hours. Then the glue solution was mixed evenly with 6wt% of conductive carbon black, coated on a polyimide film, and the film was moved to an 80°C oven and heated until the solvent was completely volatilized to prepare a conductive pressure-sensitive adhesive tape such as Figure 1 shown.
[0054] The pressure-sensitive tape was subjected to peeling performance tests and conductivity tests, and the peeling strength was measured to be 1.177 N / mm and the volume resistivity was 9.10 Ω·cm.
[0055] Example 3
[0056] Methyl methacrylate, 2-ethylhexyl acrylate and isooctyl methacrylate were mixed in a weight ratio of 2.0:4.0:4.0, and 0.6wt% of dibenzoyl peroxide was added as an initiator, and 150wt% of ethyl acetate was added as a solvent. The mixture was stirred evenly and reacted at 80°C for 2 hours. Then the glue was mixed evenly with 4wt% of conductive carbon black, coated on a polyimide film, and the film was moved to an 80°C oven and heated until the solvent evaporated.
[0057] The pressure-sensitive tape was subjected to peeling performance tests and conductivity tests, and the peeling strength was measured to be 1.287 N / mm and the volume resistivity was 28.0 Ω·cm.
[0058] Table 1 Properties of the conductive pressure-sensitive adhesive tapes prepared in Examples 1 / 2 / 3 and Comparative Example 1
[0059]
[0060] From Table 1 and the attached Figures 2 to 5It can be seen from the data of the examples and comparative examples that the conductive pressure-sensitive adhesive tape prepared in the examples of the present invention has higher peel strength.
[0061] Compared with Comparative Example 1, as the content of methyl methacrylate in Example 1 increases and the content of isooctyl methacrylate decreases, the content of hard monomers in the pressure-sensitive adhesive resin increases, thereby adjusting the flexibility of the pressure-sensitive adhesive resin segment and increasing the bonding strength of the pressure-sensitive adhesive.
[0062] Compared with Comparative Example 1, the content of 2-ethylhexyl acrylate in Example 2 is increased, the content of isooctyl methacrylate is decreased, and the content of soft monomer is increased, so that the pressure-sensitive adhesive segment is softer, which will reduce the adhesion performance of the pressure-sensitive adhesive; at the same time, the content of conductive carbon black is the largest among all the embodiments. Due to the increase of conductive carbon black, the movement of the chain segments of the pressure-sensitive adhesive resin is hindered, which reduces the adhesion ability of the pressure-sensitive adhesive, but significantly improves the conductivity of the material.
[0063] Compared with Comparative Example 1, Example 3 shows that the conductive path in the conductive pressure-sensitive adhesive is not complete due to the reduced content of the conductive carbon black, which results in a decrease in the conductive performance of the conductive pressure-sensitive adhesive. At the same time, due to the reduced content of the conductive carbon black, the segment resistance generated to the conductive pressure-sensitive adhesive resin is reduced, thereby increasing the adhesion of the conductive pressure-sensitive adhesive.
[0064] Compared with the comparative example, Examples 1-3 respectively adjusted the ratio of methyl methacrylate, 2-ethylhexyl acrylate, isooctyl methacrylate, and the ratio of acrylate monomer to conductive carbon black. By comparison, it can be found that the adhesion ability of the pressure-sensitive adhesive can be improved by adjusting the flexibility of the conductive pressure-sensitive adhesive resin segment; the higher the content of conductive carbon black, the better the conductivity, but a high content of conductive carbon black will hinder the segment movement of the pressure-sensitive adhesive resin, thereby reducing the adhesion ability of the pressure-sensitive adhesive. The conductive pressure-sensitive adhesive of the present invention can have both high-performance adhesion and conductivity.
[0065] In acrylate monomers, the length of the carbon chain ester group on the acrylate group, the presence or absence of branches, and the structure of the branches will have different degrees of influence on the performance of the polymer. For methacrylates, such as ethyl methacrylate, the catalytic temperature of the polymer decreases with the increase of the number of alkyl carbon atoms, and its softness, adhesion and reactivity tend to improve, with good initial adhesion; while for acrylates, such as methyl acrylate, as the number of carbon atoms in the ester group increases, its polarity decreases, its hydrophilicity deteriorates, its water resistance is good, and its flexibility also increases, with good viscosity, but its cohesion will decrease. For monomers containing active groups, such as methacrylic acid, the introduction of carboxyl groups can improve the wetting properties of the tape; hydroxyethyl acrylate, methacrylamide, etc., the introduction of hydroxyl groups, amides, etc. can improve the adhesion, oil resistance and weather resistance of the tape; the above acrylate monomers are selected according to the functionality required by the tape.
[0066] The pressure-sensitive adhesive of acrylate can be made up of multiple acrylate monomers, and comonomers are mainly made up of three types of monomers, i.e. soft monomers, hard monomers and functional monomers. Soft monomers make the pressure-sensitive adhesive have good initial adhesion performance, and usually used are alkyl acrylates and alkyl methacrylates with carbon atoms of 4-18, and the most commonly used ones are ethyl acrylate (EA), n-butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA) etc. However, the cohesive strength of the pressure-sensitive adhesive polymer prepared only by soft monomers is generally not high, resulting in the low performance of the pressure-sensitive adhesive. Hard monomers are monomers with higher glass transition temperatures of homopolymers. The effect is to increase the rigidity of the polymer molecular chain, produce a polymer with good cohesion and tensile strength, i.e. methyl methacrylate in the embodiment, if only selected as the preparation monomer, the pressure-sensitive adhesive film is hard, the initial adhesion is small, and the pressure sensitivity is almost lost. The content of functional monomers is relatively small. Usually, functional monomers can provide cohesion and play a modifying role, which can significantly improve the adhesion performance of pressure-sensitive adhesives. If they are missing, the microstructure of the pressure-sensitive adhesive is a linear or branched structure, and its cohesion is insufficient. During the peeling process, residual adhesive may occur. If their content is too much or they are only composed of them, the pressure-sensitive adhesive has excessive cross-linking structure, which greatly reduces or even eliminates its adhesion performance.
Claims
1. A high-bonding-strength pressure-sensitive adhesive tape having conductive properties, characterized in that: It includes a base layer and a colloid layer. The base layer is a polyimide film with a thickness of 25 microns; the colloid layer is a conductive pressure-sensitive material with a thickness of 100 microns; the optimal volume resistivity is 9.10Ω·cm, and the bonding strength reaches 1.17N / mm. Compared with the existing ones, the volume resistivity and bonding strength are both improved by more than 200%.
2. A high-bonding-strength pressure-sensitive adhesive tape with conductive properties according to claim 1, characterized in that: Used for the conduction of glass secondary surface mirrors of spacecraft to the spacecraft structure.
3. A high-bonding-strength pressure-sensitive adhesive tape with conductive properties according to claim 1, characterized in that: The colloid layer is made of a mixture of pressure-sensitive adhesive resin and conductive filler.
4. A high-bonding-strength pressure-sensitive adhesive tape with conductive properties according to claim 3, characterized in that: The pressure-sensitive adhesive resin is formed by polymerization of acrylate monomers.
5. The method for preparing a high-adhesive-strength pressure-sensitive adhesive tape with conductive properties according to any one of claims 1 to 4, characterized in that: The specific steps are as follows: Step 1, after dissolving the acrylate monomer, adding an initiator into the solution to prepare a pressure-sensitive adhesive resin; The specific preparation process is: (1) adding an acrylate monomer to a solvent and uniformly mixing the mixture at room temperature; The acrylic acid ester monomer is at least one selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, acrylic acid, acrylonitrile, isooctyl acrylate, and methacrylamide; The type and amount of the acrylic ester monomers are selected according to the desired performance of the pressure-sensitive adhesive. The acrylic monomers are classified into soft monomers, hard monomers and functional monomers. When the three types of monomers are combined for polymerization, the obtained pressure-sensitive adhesive has the best performance. Changing the ratio of the three types of monomers can adjust the flexibility of the pressure-sensitive adhesive resin chain segment and further affect the adhesion of the pressure-sensitive adhesive. The solvent is one of ethyl acetate, cyclohexane, N,N-dimethylformamide or acetone; (2) adding the initiator to the mixed solvent and uniformly mixing the mixture, and removing oxygen under nitrogen conditions; The initiator is one of dibenzoyl peroxide, azobisisobutyronitrile, tert-butyl hydroperoxide, dilauroyl peroxide or tert-butyl peroxyformate; (3) raising the temperature to 80° C. to decompose the initiator and initiate polymerization of the acrylate monomer; Step 2, mixing the pressure-sensitive adhesive resin and the conductive filler evenly to obtain a mixed adhesive solution; The mass ratio of the pressure-sensitive adhesive resin to the conductive filler is 1:0.04-0.1; The conductive filler is selected from at least one of conductive carbon black, hydroxylated multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, graphene oxide and reduced graphene oxide; Step 3, using a coating machine to evenly coat the mixed adhesive on the substrate to obtain a sample to be dried; Step 4: Transfer the sample to be dried to a blast oven for drying, and the pressure-sensitive tape can be obtained after the adhesive solution is cured into a film.
6. The preparation method according to claim 5, characterized in that: The soft monomer is an alkyl acrylate and an alkyl methacrylate with a carbon number of 4-18, which makes the pressure-sensitive adhesive have good initial adhesion performance; the hard monomer is an acrylic monomer with a high homopolymer glass transition temperature, which increases the rigidity of the polymer molecular chain and increases the cohesion and tensile strength of the polymer; the functional monomer is an acrylic monomer containing an active group, which provides cohesion and plays a role of modification, thereby improving the adhesion performance of the pressure-sensitive adhesive.
7. The preparation method according to claim 6, characterized in that: The content of the hard monomer is preferably 10-35 parts by weight, the content of the soft monomer is preferably 20-50 parts by weight, and the content of the functional monomer is preferably 20-40 parts by weight.
8. The preparation method according to claim 5, characterized in that: The initiator is preferably azobisisobutyronitrile or dibenzoyl peroxide.
9. The preparation method according to claim 5, characterized in that: The conductive filler is preferably carboxylated multi-walled carbon nanotube or conductive carbon black.
10. The preparation method according to claim 5, characterized in that: The substrate is selected from a polyimide film having radiation resistance.