Conductive adhesive tape release film

Abstract

The invention discloses a conductive adhesive tape release film, which belongs to the technical field of conductive adhesive tapes and comprises the following components in parts by mass: 8 to 32 parts of solvent type organic silicon, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8 to 10 parts of styrene, 1 to 2 parts of epoxy resin E-44 and 1 to 2 parts of dibenzoyl peroxide. The release film provided by the invention has high surface tension and keeps medium stripping force, so that the condition that the release film is easily separated from the conductive adhesive tape accidentally during turnover or use in the prior art can be solved; and the release film can be stripped as required. Therefore, the conductive adhesive tape release film solves the technical problem of how to improve the release force of the release film.

Description

Technical Field

[0001] The invention relates to the technical field of conductive tapes, in particular to a conductive tape release film. Background Art

[0002] Conductive tape is a special tape with electrical conductivity. Its main function is to transfer current in the circuit. It is usually used in the bonding, packaging and electrical connection of electronic components. Conductive tape has the characteristics of good conductivity, high viscosity and easy processing, which can significantly improve the reliability and production efficiency of the circuit.

[0003] At present, the core structure of conductive tape mainly includes a conductive layer, an adhesive layer and a release layer; the conductive layer is the core of the conductive tape, which is usually composed of conductive particles, conductive fibers or conductive metal foils; these components can effectively transmit current and ensure that the tape has excellent conductive properties. The adhesive layer is the key to forming a tight connection between the conductive tape and the adherend; it is responsible for firmly sticking the conductive tape to the part that needs to be conductive. The release layer is the carrier of the conductive tape, which supports the conductive layer and the adhesive layer and provides the necessary mechanical strength and insulation performance; it is usually made of insulating materials such as polyester film, polyimide film or paper. These materials not only have good mechanical properties, but also can effectively isolate the direct contact between the conductive layer and the external environment to ensure safety in use.

[0004] Based on this, Chinese patent CN209397154U discloses an adhesive, covering, and conductive integrated die-cut tape, which integrates adhesive tapes or films with various functions such as adhesive, covering, and conductive, and only requires one release layer, which can significantly reduce the production process and production cost of tape users. It includes a single-sided conductive tape, the adhesive surface of the single-sided conductive tape is bonded with a double-sided conductive tape, and the conductivity of the single-sided conductive tape and the double-sided conductive tape is different; a PET covering film and an adhesive insulating film are bonded on the surface of the double-sided conductive tape, and the PET covering film, the adhesive insulating film, the double-sided conductive tape not covered by the PET covering film and the adhesive insulating film, and the single-sided conductive tape not covered by the double-sided conductive tape are all bonded to the release layer, and the outer contour of the release layer is larger than the outer contour of the single-sided conductive tape.

[0005] However, the release film disclosed above still has the technical problem of poor surface tension. Specifically, conductive tape has achieved tremendous development as a new product after its launch, and the release film as a basic material is one of the indispensable materials for producing conductive tape. Therefore, the market demand for release film used for conductive tape is also increasing. The release film of early conductive tape was mainly composed of PET, PVC and other materials. The release film composed of these materials has the advantage of thin thickness; but the disadvantages are also obvious. Its surface tension cannot fully meet the use requirements of conductive tape, because the adhesive of conductive tape is usually based on resin, and then made by adding curing agent and tackifier and other ingredients; thus, it causes the adhesive layer to be unable to spread well on films such as PET with low surface energy; in actual turnover and use, it is easy for the tape and the release film to separate accidentally in advance. This puts forward new requirements for the surface tension of the release film. Summary of the invention

[0006] Based on this, it is necessary to provide a conductive tape release film to address the technical problem of how to improve the peeling force of the release film.

[0007] A conductive adhesive tape release film comprises, by weight, 8 to 32 parts of solvent-based silicone, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8 to 10 parts of styrene, 1 to 2 parts of epoxy resin E-44 and 1 to 2 parts of dibenzoyl peroxide.

[0008] An embodiment of a conductive tape release film comprises, by mass, 8 parts of solvent-based silicone, 35 parts of acrylic acid, 25 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0009] Another embodiment of the conductive tape release film comprises, by weight, 32 parts of solvent-based silicone, 25 parts of acrylic acid, 15 parts of butyl acrylate, 12 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0010] Another embodiment of the conductive tape release film comprises, by weight, 25 parts of solvent-based silicone, 30 parts of acrylic acid, 15 parts of butyl acrylate, 15 parts of trifluoroethyl methacrylate, 10 parts of styrene, 42 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0011] Another embodiment of the conductive tape release film comprises, by weight, 20 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 18 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 1 part of dibenzoyl peroxide.

[0012] Another embodiment of the conductive tape release film comprises, by weight, 152 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0013] In summary, the present invention discloses a conductive tape release film, the components of which include, by mass: 8 to 32 parts of solvent-based silicone, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8-10 parts of styrene, 1-2 parts of epoxy resin E-44, and 1-2 parts of dibenzoyl peroxide. The release film proposed in the present invention has high surface tension while maintaining a moderate peeling force, which can solve the problem in the prior art that the release film is easily separated from the conductive tape accidentally during turnover or use; it can also ensure that the release film can be peeled off as needed. Therefore, the conductive tape release film of the present invention solves the technical problem of how to improve the peeling force of the release film. DETAILED DESCRIPTION

[0014] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0015] Specifically, in parts by mass, the components of a conductive tape release film of the present invention include: 8 to 32 parts of solvent-based silicone, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8-10 parts of styrene, 1-2 parts of epoxy resin E-44 and 1-2 parts of dibenzoyl peroxide.

[0016] Furthermore, in several specific embodiments of a conductive tape release film of the present invention, the proportions of each component are as follows, calculated by weight: Example 1: 8 parts of solvent-based silicone, 35 parts of acrylic acid, 25 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0017] Example 2: 32 parts of solvent-based silicone, 25 parts of acrylic acid, 15 parts of butyl acrylate, 12 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0018] Example 3: 25 parts of solvent-based silicone, 30 parts of acrylic acid, 15 parts of butyl acrylate, 15 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0019] Example 4: 20 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 18 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 1 part of dibenzoyl peroxide.

[0020] Example 5: 152 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

[0021] Furthermore, a process for preparing a release film product from the formula of a conductive tape release film of the present invention comprises the following steps: S1: prepare toluene solvent at twice the mass ratio of solvent-based silicone in the preset formula; S2: according to a preset formula, all the solvent-based silicone, 60% by mass of toluene solvent, 30% by mass of acrylic acid, 30% by mass of butyl acrylate, 40% by mass of trifluoroethyl methacrylate and 50% by mass of styrene are loaded into a reactor; S3: Take 5% by weight of toluene and 40% by weight of dibenzoyl peroxide in another container, stir them thoroughly to dissolve all the dibenzoyl peroxide, and then put the container into the reactor in step S2 for standby use; S4: put the remaining materials in the formula and all the remaining toluene into another container, stir them thoroughly and set aside; S5: Start stirring the reactor in step S2 to mix the raw materials in the reactor evenly, and at the same time, raise the temperature in the reactor to 80±2°C; S6: injecting the material in the vessel prepared in step S3 into the reactor at a uniform speed, and the injection time is controlled between 1 and 2 minutes; S7: Keep the components in the reactor reacting for 1 hour, and after 1 hour, when the liquid in the reactor turns white, increase the temperature in the reactor to 90±3°C; S8: inject the material in the vessel prepared in step S4 into the reactor at a uniform speed, and control the injection time to be between 2.5 and 3 hours. After the injection is completed, heat the reactor to 95±3° C. and keep it warm for another hour; S9: drying the synthesized product in step S8 in an oven at 60° C. for 48 hours until constant weight is reached, taking it out and placing it in an extraction device, extracting it with ethanol for 72 hours to remove the self-polymer of acrylic acid in the system, and after extraction, placing the synthesized emulsion in an oven at 60° C. for 48 hours until constant weight is reached; S10: The synthetic emulsion is prepared into a coating liquid, and the coating liquid is applied on the BOPET film by using a screen coater, the coating speed is 60 m / min, the oven temperature is 150°C, and a completely colorless and transparent release film is obtained by coating. The obtained release film is then cut into rolls as required, packaged and sent to a curing room, and the finished release film is obtained after curing.

[0022] Specifically, in a conductive tape release film of the present invention, the solvent-based silicone used is a high molecular weight dimethylsiloxane with a vinyl double bond. The full name of the solvent-based silicone is vinyl dimethylsiloxane; wherein, there is one vinyl double bond per 200 silicon atoms. The material is mainly used for coating on the surface of kraft paper, and the coated product is used as release paper in the packaging industry. It can also be coated on the surface of BOPET, and the coated product can be used as a release film.

[0023] Furthermore, the present invention uses acrylic acid as the main material of the modified solvent-based silicone, and acrylic acid ester monomers as the supporting materials of the modified silicone. The double bonds in the acrylic acid monomers are reactive functional groups, both of which contain carboxyl and ester groups with high surface tension and can be dissolved in most common organic solvents; moreover, they are easily available in the market and are inexpensive, which can effectively control production costs.

[0024] Furthermore, the present invention requires that the final release film product has good film-forming properties, leveling properties, transparency, heat resistance and a relatively high glass transition temperature in addition to high surface tension. Acrylic acid alone cannot meet the requirements, and polyacrylic acid has strong crystallinity; moreover, the film is too brittle; therefore, a method of copolymerizing multiple monomers can be used. Therefore, the present invention uses butyl acrylate, which has a similar activity to acrylic acid, for copolymerization, which can not only eliminate crystallinity, but also increase the flexibility of the molecular chain segments, and at the same time, increase the toughness of the release film. Furthermore, the combination of these two with trifluoroethyl methacrylate can also improve the adhesion strength between the final release film and the substrate and the transparency of the film.

[0025] Furthermore, since acrylic acid is used as the main material of the modified solvent-based silicone, it is easy to cause the product to be intolerant to polar solvents after film formation. In order to improve the tolerance to polar solvents, styrene can also be added to the formula to improve the polar solvent resistance of the modified silicone material. Since styrene contains benzene rings, the large π bond in the benzene ring can also increase the surface tension of the final release film product; however, styrene will also affect the bonding strength between the material and the substrate, so its addition amount needs to be limited; therefore, the present invention discloses that its addition amount is 8-10 parts.

[0026] Specifically, in the aforementioned manufacturing process, dibenzoyl peroxide is selected as the initiator of the reaction. This is because, in the aforementioned manufacturing process, although an emulsion is obtained, the free radical reaction process is completed in toluene; therefore, an oil-soluble initiator should be selected. Among the oil-soluble initiators, there are two major types of initiators commonly used in acrylic acid polymerization reactions: organic peroxides and azo compounds. In order to obtain a uniform copolymerization product, the reaction temperature cannot be too low, so the present invention selects dibenzoyl peroxide as the initiator.

[0027] In addition, in order to avoid the problems of poor product compatibility and small molecule migration to the surface after long-term storage in the process of making release film, epoxy E-44 is added as a coupling agent in the middle and late stages of the reaction, so that the silicone macromolecule grafted with acrylic acid / ester and the acrylic acid / ester polymer react with macromolecules in the middle and late stages of the synthesis, thereby increasing the grafting rate of acrylic acid / ester on solvent-based silicone; cross-linking is carried out by utilizing the reaction between epoxy and carboxyl groups, and the molecular weight of the synthetic product is increased by the reaction between epoxy and carboxyl groups, while the content of acrylic acid / ester self-polymer in the system is also reduced. Try to make each epoxy molecule react with four carboxyl groups, so that the acrylic acid / ester polymer grafted on silicone has a high degree of branching, which can improve the solubility of the product in polar solvents, thereby forming a uniform and stable solution system. The addition of coupling agent makes the product have good film-forming properties and toughness. The addition of coupling agent in the preparation process greatly increases the molecular weight of the product, so that it can form a film after coating, thereby improving the operability of the later process. The coupling agent increases the amount of grafted acrylic acid / ester on the silicone and improves the solubility of the grafted solvent-based silicone in polar solvents, which serves as a guarantee for obtaining a colorless and transparent film in the end.

[0028] Specifically, a common experimental method can be used to test the surface tension and peeling force of the release films made in the above-mentioned embodiments. The details are as follows: Surface tension test method: Use a surface tension test pen to draw three lines at the same strength and speed at different positions of the finished release film; after the third line is drawn, observe whether the first line shrinks, and the control time is about 2s. If it shrinks, it means that the surface tension of the release film is less than the value corresponding to this pen; if it does not shrink, use a pen with a higher surface tension value; if it shrinks, it will be the value corresponding to the previous pen, and if it still does not shrink, use the next pen.

[0029] Peel force test method: stick TESA7454 tape on the release film to be tested according to the standard method, cut it into long strips according to the shape of the tape, press a standard stainless steel bar at room temperature for 20 hours, 20g / cm; test with a release force tester; set the stretching speed to 30cm / min, and the tensile force at the stretching angle of 180° is the release force.

[0030] The surface tension and peeling force test methods described above were used to measure the surface tension and peeling force of the above-mentioned embodiments, as shown in Table 1 below; wherein the comparative example is a conventional PET release film available on the market.

[0031] Table 1: Test data of various embodiments

[0032] From the test data in Table 1, it can be seen that compared with the common PET release film on the market, the surface tension data of the release film of the conductive tape of the present invention is significantly improved, and the surface tension data of each group of embodiments are similar, that is, the properties of the release film are uniform and stable; similarly, the test data of the peeling force also have similar performance. Since the peeling force of 16-24g / cm can usually reach the standard of medium peeling force, and the embodiments disclosed in the present invention all reach the standard of medium peeling force, which can be significantly improved compared with the common PET release film; therefore, it can be shown that the present invention can improve the peeling force of the release film used for the conductive tape.

[0033] In summary, the present invention discloses a conductive tape release film, the components of which include, by mass: 8 to 32 parts of solvent-based silicone, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8-10 parts of styrene, 1-2 parts of epoxy resin E-44, and 1-2 parts of dibenzoyl peroxide. The release film proposed in the present invention has high surface tension while maintaining a moderate peeling force, which can solve the problem in the prior art that the release film is easily separated from the conductive tape accidentally during turnover or use; it can also ensure that the release film can be peeled off as needed. Therefore, the conductive tape release film of the present invention solves the technical problem of how to improve the peeling force of the release film.

[0034] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A conductive tape release film, It is characterized in that The components include, by mass, 8 to 32 parts of solvent-based silicone, 25 to 35 parts of acrylic acid, 15 to 25 parts of butyl acrylate, 12 to 22 parts of trifluoroethyl methacrylate, 8-10 parts of styrene, 1-2 parts of epoxy resin E-44 and 1-2 parts of dibenzoyl peroxide.

2. The conductive tape release film according to claim 1, wherein the components are include: 8 parts of solvent-based silicone, 35 parts of acrylic acid, 25 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

3. The conductive tape release film according to claim 1, wherein the components are include: 32 parts of solvent-based silicone, 25 parts of acrylic acid, 15 parts of butyl acrylate, 12 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

4. The conductive tape release film according to claim 1, wherein the components are include: 25 parts of solvent-based silicone, 30 parts of acrylic acid, 15 parts of butyl acrylate, 15 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

5. The conductive tape release film according to claim 1, wherein the components are include: 20 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 18 parts of trifluoroethyl methacrylate, 8 parts of styrene, 1 part of epoxy resin E-44 and 1 part of dibenzoyl peroxide.

6. The conductive tape release film according to claim 1, wherein the components are include: 152 parts of solvent-based silicone, 35 parts of acrylic acid, 20 parts of butyl acrylate, 22 parts of trifluoroethyl methacrylate, 10 parts of styrene, 2 parts of epoxy resin E-44 and 2 parts of dibenzoyl peroxide.

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