Preparation method of thermal debonding film

Abstract

The invention discloses a preparation method of a thermal viscosity-reducing film, and relates to the technical field of viscosity-reducing films, the thermal viscosity-reducing film is prepared from the following components: 30-60 parts of a resin matrix, 10-20 parts of a high-temperature ring-opening cross-linking agent, 5-10 parts of a tackifier, 5-10 parts of a temperature-sensitive polymer, 2-5 parts of a thermal stabilizer and a plurality of solvents.The preparation method comprises the following steps: dissolving the resin matrix in the solvent; stirring and dispersing uniformly to obtain a resin solution; adding a high-temperature ring-opening cross-linking agent, a tackifier, a temperature-sensitive polymer and a heat stabilizer into the resin solution, and uniformly stirring and dispersing to obtain a glue solution; coating the surface of the base material with the glue solution to form a glue layer; and drying the adhesive layer, and removing the solvent to obtain the thermal viscosity-reduced film. The thermal visbreaking film has high adhesive force at normal temperature, and a cross-linked network in the visbreaking film is formed under the action of the high-temperature ring-opening cross-linking agent at high temperature, so that thermal visbreaking is realized in a high-temperature environment, the stripping force is remarkably reduced, and the thermal visbreaking film has strong innovativeness and industrial application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of anti-viscosity films, and in particular to a method for preparing a thermal anti-viscosity film. Background Art

[0002] With the increasing demand for film materials in modern packaging, electronics and automotive industries, thermal viscosity reduction films, as a material that can reduce adhesion at high temperatures, have received widespread attention. These films show high adhesion at room temperature, but the adhesion of the film decreases after being heated to a certain temperature. However, the existing thermal viscosity reduction film preparation technology is not perfect in composition and process, and the phase change properties of the polymer in the film in different temperature ranges are still unstable, so that the ideal viscosity reduction effect cannot be shown at high temperatures, resulting in insufficient reduction in the adhesion of the film. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for preparing a thermal viscosity-reducing film, and the specific technical solution is as follows:

[0004] A method for preparing a thermal viscosity-reducing film, the thermal viscosity-reducing film comprises the following components: by weight, 30 to 60 parts of a resin matrix, 10 to 20 parts of a high-temperature ring-opening cross-linking agent, 5 to 10 parts of a tackifier, 5 to 10 parts of a temperature-sensitive polymer, 2 to 5 parts of a thermal stabilizer, and a number of solvents. The preparation method comprises the following steps:

[0005] Step 1: dissolving the resin matrix in a solvent, stirring and dispersing the mixture evenly to obtain a resin solution;

[0006] Step 2: Add the high temperature ring-opening cross-linking agent, tackifier, temperature sensitive polymer and thermal stabilizer to the resin solution, and stir and disperse them evenly to obtain a glue solution;

[0007] Step 3: Apply the glue solution to the surface of the substrate to form a glue layer;

[0008] Step 4: Dry the adhesive layer and remove the solvent to obtain the thermal viscosity-reducing film.

[0009] Preferably, step 2 specifically includes the following sub-steps:

[0010] Step 21: adding a high temperature ring-opening cross-linking agent to the resin solution obtained in step 1, and stirring and dispersing the mixture at 40 to 50° C.;

[0011] Step 22: slowly add the thickener into the solution obtained in step 21, stirring continuously during the addition process to ensure uniform dispersion;

[0012] Step 23: adding the temperature-sensitive polymer to the solution obtained in step 22, and subjecting the solution to ultrasonic treatment until the solution is completely dissolved;

[0013] Step 24: Add the heat stabilizer to the solution obtained in step 23 and stir to disperse evenly.

[0014] Preferably, the resin matrix is ​​polyurethane resin or acrylic resin, and the solvent is acetone or ethanol.

[0015] Preferably, the high temperature ring-opening cross-linking agent is an epoxy resin curing agent, a benzoxazole cross-linking agent or a cyclic olefin cross-linking agent.

[0016] Preferably, the tackifier is polyvinyl alcohol or a polyether tackifier.

[0017] Preferably, the temperature-sensitive polymer is N-isopropylacrylamide.

[0018] Preferably, the thermal stabilizer is an organic phosphate or a metal complex.

[0019] Preferably, the concentration of the glue solution in step 2 is 20% to 50%.

[0020] Preferably, the coating method in step 3 is blade coating, spin coating or dip coating.

[0021] Preferably, in step 4, the drying temperature is 60-80° C. and the drying time is 10-30 min.

[0022] The thermal viscosity-reducing film prepared by the preparation method provided by the present invention has high adhesion at room temperature. At high temperature, due to the action of the high-temperature ring-opening cross-linking agent, a cross-linking network is formed in the viscosity-reducing film, thereby achieving thermal viscosity reduction under high-temperature environment, and the peeling force is significantly reduced. It has strong innovation and industrial application prospects. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0024] The present embodiment provides a method for preparing a thermal viscosity-reducing film, wherein the thermal viscosity-reducing film comprises the following components: by weight, 30 to 60 parts of a resin matrix, 10 to 20 parts of a high-temperature ring-opening cross-linking agent, 5 to 10 parts of a tackifier, 5 to 10 parts of a temperature-sensitive polymer, 2 to 5 parts of a thermal stabilizer, and a number of solvents. The preparation method comprises the following steps:

[0025] Step 1: Dissolve the resin matrix in the solvent, and stir and disperse it evenly to obtain a resin solution.

[0026] Step 2: Add the high-temperature ring-opening cross-linking agent, tackifier, temperature-sensitive polymer and thermal stabilizer to the resin solution, and stir and disperse them evenly to obtain a glue solution.

[0027] Step 3: Apply the glue solution to the surface of the substrate to form a glue layer.

[0028] Step 4: Dry the adhesive layer and remove the solvent to obtain a heat-reduced adhesion film.

[0029] Among them, the resin matrix uses thermosetting resin or thermoplastic resin as the base, which has certain room temperature bonding properties; the added tackifier can enhance the peeling force at room temperature; the high-temperature ring-opening cross-linking agent can undergo a cross-linking reaction at high temperature, which causes cross-linking between molecules when heated, changes the structure of the resin, and thus reduces its adhesion; the added temperature-sensitive polymer can undergo conformational changes within a specific temperature range, which significantly reduces the adhesion; the thermal stabilizer helps to keep the viscosity-reducing film from degrading at high temperatures, and at the same time can improve the effect of the cross-linking reaction.

[0030] The thermal viscosity-reducing film prepared by the preparation method provided in this embodiment has high adhesion at room temperature. At high temperatures, due to the action of the high-temperature ring-opening cross-linking agent, a cross-linking network is formed in the viscosity-reducing film, thereby achieving thermal viscosity reduction under high-temperature conditions, and the peeling force is significantly reduced, which has strong innovation and industrial application prospects.

[0031] Furthermore, step 2 specifically includes the following sub-steps:

[0032] Step 21: Add the high-temperature ring-opening cross-linking agent to the resin solution obtained in step 1, and stir and disperse evenly at 40-50°C.

[0033] Step 22: Slowly add the thickener into the solution obtained in step 21, stirring continuously during the addition process to ensure uniform dispersion.

[0034] Step 23: Add the temperature-sensitive polymer to the solution obtained in step 22 and treat with ultrasound until it is completely dissolved.

[0035] Step 24: Add the heat stabilizer to the solution obtained in step 23 and stir to disperse evenly.

[0036] Furthermore, the resin matrix is ​​polyurethane resin or acrylic resin, and the solvent is acetone or ethanol.

[0037] Among them, polyurethane adhesives have good adhesion and flexibility, and can provide higher peeling force at room temperature; acrylic adhesives have good weather resistance and room-temperature bonding properties.

[0038] Furthermore, the high temperature ring-opening cross-linking agent is an epoxy resin curing agent, a benzoxazole cross-linking agent or a cyclic olefin cross-linking agent.

[0039] Among them, epoxy resin has good adhesion at room temperature, but after heating, it can undergo a cross-linking reaction with the epoxy group through the curing agent to form a network structure, thereby reducing the adhesion; benzoxazole or benzoxazole ether cross-linking agents can achieve a cross-linking reaction at a higher temperature, resulting in a change in the structure of the viscose, thereby reducing the peeling force at high temperature; cyclic olefin cross-linking agents can undergo a cross-linking reaction through thermal decomposition or ring-opening reaction at a higher temperature, reducing the mutual attraction between molecules, thereby reducing the adhesion performance.

[0040] Furthermore, the tackifier is polyvinyl alcohol or a polyether tackifier, which can enhance the peeling force at room temperature.

[0041] Furthermore, the temperature-sensitive polymer is N-isopropylacrylamide, which can undergo conformational changes within a specific temperature range, so that the adhesion is significantly reduced.

[0042] Furthermore, the heat stabilizer is an organic phosphate or a metal complex, which helps to prevent the viscose from being degraded at high temperatures and can also improve the effect of the cross-linking reaction.

[0043] Furthermore, the concentration of the glue solution in step 2 is 20% to 50%, and the specific concentration can be selected according to the glue coating method and the corresponding glue viscosity.

[0044] Furthermore, in step 3, the coating method adopts scraping, spin coating or dipping. If scraping is adopted, the glue solution can be adjusted to a medium viscosity (1000-5000 mPa·s), and it can be coated at a higher thickness, and the excess part can be scraped off with a knife to control the thickness of the film; if spin coating is adopted, the glue solution can be adjusted to a lower viscosity (50-1000 mPa·s) to obtain a very uniform and thin coating. The lower viscosity makes it easier for the liquid to be evenly distributed when it rotates rapidly; if dipping is adopted, the viscosity range can be controlled within 100-2000 mPa·s. Too high viscosity will result in uneven film thickness, and too low viscosity may not form good interfacial adhesion.

[0045] Furthermore, in step 4, the drying temperature is 60-80° C., and the drying time is 10-30 min.

[0046] Among them, after the film is dried, in order to achieve the effect of reducing adhesion at high temperature, it is necessary to promote the cross-linking reaction by heating. The cross-linking temperature is usually between 150 and 180 ° C, depending on the characteristics of the open-ring cross-linking agent used. The specific temperature needs to be determined according to the melting point of the cross-linking agent, the reaction temperature and the heat resistance of the resin. The cross-linking time is usually 30 to 60 minutes. During the cross-linking process, chemical reactions will occur between the resin molecules to form a network structure, which will increase the rigidity of the adhesive layer and reduce the adhesion. The temperature control process can choose to gradually increase the temperature to avoid damage to the film due to rapid temperature increase. First, preheat at a lower temperature (about 80 ° C), and then cross-link and cure at a higher temperature (about 160 ° C).

[0047] Specific examples are provided below. The provided examples may enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0048] Embodiment 1:

[0049] The resin matrix is ​​made of polyurethane resin, which accounts for 40% of the total mass.

[0050] The high temperature ring-opening cross-linking agent is an epoxy resin curing agent, and its mass accounts for 15% of the mass of the resin matrix.

[0051] The tackifier is polyvinyl alcohol, which accounts for 7% of the mass of the resin matrix.

[0052] The temperature sensitive polymer is N-isopropylacrylamide (PNIPAAm), and its mass accounts for 8% of the mass of the resin matrix.

[0053] The heat stabilizer is an organic phosphate heat stabilizer, and its mass accounts for 3% of the mass of the resin matrix.

[0054] The balance is solvent, acetone is selected.

[0055] Process steps:

[0056] The polyurethane resin is dissolved in acetone to form a resin solution.

[0057] The epoxy resin hardener, polyvinyl alcohol, PNIPAAm, and thermal stabilizer are sequentially added into the resin solution and stirred evenly to obtain a glue solution.

[0058] Apply the glue solution to the surface of the substrate by scraping to form a glue layer.

[0059] The adhesive layer was placed in an oven, the temperature was adjusted to 60°C, and dried for 30 minutes to remove the solvent to obtain a dry film, i.e., a thermal viscosity-reducing film.

[0060] Embodiment 2:

[0061] The only difference between this embodiment and embodiment 1 is that the temperature-sensitive polymer is replaced by polyvinyl alcohol-polyvinyl ether copolymer (PEO-PVA), and the other formulations and process steps remain unchanged.

[0062] The thermal viscosity-reducing films prepared in Example 1 and Example 2 were subjected to a peeling force test, and the test results are as follows:

[0063] At room temperature (25°C):

[0064] Example 1: The peel force is 270 g / 25 mm.

[0065] Example 2: The peel force is 260 g / 25 mm.

[0066] At high temperature (80℃):

[0067] Example 1: The peel force is reduced to 70 g / 25 mm, which is a reduction of about 74%.

[0068] Example 2: The peel force is reduced to 80 g / 25 mm, which is a reduction of about 69%.

[0069] At high temperature (150℃):

[0070] Example 1: The peel force is reduced to 25 g / 25 mm, which is a reduction of about 91%.

[0071] Example 2: The peel force is reduced to 35 g / 25 mm, which is a reduction of about 87%.

[0072] By testing the peeling force of the films at different temperatures, it was found that the film of Example 1 exhibited a significant thermal viscosity reduction effect in the temperature range above 80°C, while the thermal responsiveness of the film of Example 2 was slightly poor at higher temperatures.

[0073] Principle description:

[0074] The resin matrix uses thermosetting resin or thermoplastic resin as the base, which has certain room temperature bonding properties; the added tackifier can enhance the peeling force at room temperature; the high-temperature ring-opening cross-linking agent can undergo a cross-linking reaction at high temperature, causing cross-linking between molecules when heated, changing the structure of the resin, thereby reducing its adhesion; the added temperature-sensitive polymer can undergo conformational changes within a specific temperature range, significantly reducing the adhesion; the thermal stabilizer helps to keep the viscosity-reducing film from degrading at high temperatures, and at the same time can improve the effect of the cross-linking reaction.

[0075] The principles and implementation methods of the present invention are described herein using specific examples, and the description of the above embodiments is only used to help understand the method and core ideas of the present invention. The above are only preferred implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, which should be within the protection scope of the present invention.

Claims

1. A method for preparing a thermal viscosity-reducing film, characterized in that: The thermal viscosity-reducing film comprises the following components: by weight, 30 to 60 parts of a resin matrix, 10 to 20 parts of a high-temperature ring-opening crosslinking agent, 5 to 10 parts of a tackifier, 5 to 10 parts of a temperature-sensitive polymer, 2 to 5 parts of a thermal stabilizer, and a number of solvents. The preparation method comprises the following steps: S1: dissolving the resin matrix in a solvent, stirring and dispersing the mixture evenly to obtain a resin solution; S2: adding a high temperature ring-opening cross-linking agent, a tackifier, a temperature-sensitive polymer and a heat stabilizer to the resin solution, stirring and dispersing the mixture evenly to obtain a glue solution; S3: applying the glue solution to the surface of the substrate to form a glue layer; S4: Drying the adhesive layer to remove the solvent to obtain the thermal viscosity-reducing film.

2. The preparation method according to claim 1, characterized in that: Step S2 specifically includes the following sub-steps: S21: adding a high temperature ring-opening cross-linking agent to the resin solution obtained in step S1, and stirring and dispersing the mixture at 40 to 50° C. to uniformly disperse the mixture; S22: slowly adding the thickener into the solution obtained in step S21, stirring continuously during the addition process to ensure uniform dispersion; S23: adding the temperature-sensitive polymer to the solution obtained in step S22, and subjecting the solution to ultrasonic treatment until the polymer is completely dissolved; S24: Add the heat stabilizer to the solution obtained in step S23, and stir to disperse evenly.

3. The preparation method according to claim 1, characterized in that: The resin matrix is ​​polyurethane resin or acrylic resin, and the solvent is acetone or ethanol.

4. The preparation method according to claim 1, characterized in that: The high temperature ring-opening cross-linking agent is an epoxy resin curing agent, a benzoxazole cross-linking agent or a cyclic olefin cross-linking agent.

5. The preparation method according to claim 1, characterized in that: The tackifier is polyvinyl alcohol or a polyether tackifier.

6. The preparation method according to claim 1, characterized in that: The temperature sensitive polymer is N-isopropylacrylamide.

7. The preparation method according to claim 1, characterized in that: The heat stabilizer is an organic phosphate or a metal complex.

8. The preparation method according to claim 1, characterized in that: The concentration of the glue solution in step S2 is 20% to 50%.

9. The preparation method according to claim 1, characterized in that: The coating method in step S3 is a scraping method, a spin coating method or a dip coating method.

10. The preparation method according to claim 1, characterized in that: In step S4, the drying temperature is 60-80° C. and the drying time is 10-30 min.