Yellowing-resistant insulating flame-retardant adhesive film and manufacturing method thereof

Abstract

The invention discloses an anti-yellowing insulating flame-retardant adhesive film which is characterized by comprising an insulating base film and an adhesive, the adhesive is prepared from the following raw materials: matrix resin, epoxy resin, a flame retardant, fumed silica, titanium dioxide, a curing agent, a catalyst and tackifying resin. On the basis that the original main material epoxy resin is replaced with polyester, the titanium dioxide with the blue coloring base phase is added, so that compared with the prior art, the adhesive film is whiter in color and achieves the effect of neutralizing yellowing, and meanwhile, the titanium dioxide with the blue base phase is smaller in particle size, has good covering performance and can also cover part of yellowing; the insulating flame-retardant adhesive film has good cohesiveness, flame retardance, temperature resistance and storage performance, the yellowing resistance of the adhesive film is improved, the situation that in subsequent processing engineering, due to human factors, the adhesive film is polluted, and the adhesive film is yellowed is avoided, waste of materials is reduced, and the processing efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field, in particular to a yellowing-resistant insulating flame-retardant adhesive film and a manufacturing method thereof. Background Art

[0002] Laminated busbar, also known as laminated busbar, composite copper busbar, is a multi-layer composite structure connection bar. Compared with the traditional, bulky, time-consuming and troublesome wiring method, the use of composite busbar can provide a modern, easy to design, fast to install and clearly structured distribution system. With the development of the power industry, busbars are more widely used, driving the development of insulating flame retardant film.

[0003] In the existing flame-retardant insulating adhesive films, epoxy resin is the main component in the formula. For example, (CN111040670A) discloses an adhesive and a preparation method thereof, and a PET insulating adhesive film containing the adhesive. The adhesive comprises the following components in parts by weight: 100 parts of epoxy resin, 20-100 parts of rubber, 5-30 parts of curing agent, and 50-150 parts of flame retardant. The curing agent comprises a mixture of anhydride epoxy resin flexible curing agent and polymer epoxy resin flexible curing agent. The present invention cures epoxy resin by compounding a specific type of curing agent, and then matches rubber and flame retardant, so that the obtained adhesive has good adhesion. The PET insulating adhesive film obtained by the adhesive has good adhesion, high electrical stability, excellent long-term high temperature resistance and flame retardant performance, excellent comprehensive performance, and has a very broad application prospect. It can be seen from the above content that the main resin in the existing insulating flame-retardant film is epoxy resin, and the film will inevitably turn yellow when heated. The yellowing of the film leads to the problem of unqualified product appearance. Combined with the experimental phenomena, the possible reasons for the yellowing are as follows: 1. The film containing epoxy resin is oxidized and turns yellow when heated during the processing. 2. During the processing, the operator's hands directly contact the components and then contact the film, causing contamination to the film. The contaminated area turns yellow after processing. Therefore, we propose a yellowing-resistant insulating flame-retardant film and a manufacturing method thereof. Summary of the invention

[0004] The object of the present invention is to provide a yellowing-resistant insulating flame-retardant adhesive film and a manufacturing method thereof, so as to solve the problems that need to be solved in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: a yellowing-resistant insulating flame-retardant adhesive film, comprising an insulating base film and an adhesive, wherein the adhesive is disposed above the insulating base film;

[0006] The manufacturing raw materials of the adhesive include main resin, epoxy resin, flame retardant, gas-phase silica, titanium dioxide, curing agent, catalyst and tackifying resin.

[0007] As a further description of the above technical solution:

[0008] The weight proportions of the raw materials for manufacturing the adhesive are: 90-100 parts of main resin, 0-10 parts of epoxy resin, 70-80 parts of flame retardant, 0-1 part of fumed silica, 2.5-10 parts of titanium dioxide, 1-10 parts of curing agent, 0.001-2 parts of catalyst and 0-10 parts of tackifying resin.

[0009] The main resin in the existing insulating flame-retardant film is epoxy resin, and the film will inevitably turn yellow when heated. The yellowing of the film leads to the problem of unqualified product appearance. Combined with experimental phenomena, the possible reasons for the yellowing are as follows: 1. The film contains epoxy resin, and the epoxy resin is oxidized and turns yellow when heated during processing; 2. During the processing, the operator's hands directly contact the components and then contact the film, causing pollution to the film. The polluted area turns yellow after processing. The raw materials for manufacturing the insulating film of the present invention are all conventional materials, which are simple and easy to obtain, and the manufacturing method is relatively simple, which is convenient for mass production of the insulating film; and the present invention The invention replaces the original main material epoxy resin with polyester, and adds titanium dioxide with a blue coloring base phase to make the film whiter in color compared with the prior art, thereby achieving the effect of neutralizing yellowing. At the same time, the titanium dioxide with a blue base phase has a smaller particle size and good covering performance, and can also cover part of the yellowing. Secondly, the insulating flame retardant film of the invention not only has good adhesion, flame retardant properties, heat resistance and good storage properties, but also improves the yellowing resistance of the film, thereby avoiding yellowing of the film due to human factors in subsequent processing projects after the film is contaminated, thereby reducing material waste and improving processing efficiency.

[0010] As a further description of the above technical solution:

[0011] The manufacturing materials of the insulating base film include but are not limited to PP film, PE film, PET film, and PI film.

[0012] As a further description of the above technical solution:

[0013] The coloring base phase of the titanium dioxide is blue, and the main resin is polyester.

[0014] As a further description of the above technical solution:

[0015] The method for making a yellowing-resistant insulating flame-retardant adhesive film includes a single-sided adhesive film manufacturing method and a double-sided adhesive film manufacturing method.

[0016] As a further description of the above technical solution:

[0017] The manufacturing method of the single-sided adhesive film comprises the following steps:

[0018] Step 1: stirring and mixing the main resin, epoxy resin, catalyst and tackifying resin to obtain a crude material A;

[0019] Step 2: Mix and stir the flame retardant, titanium dioxide and fumed silica in the raw materials for manufacturing the processing adhesive, and divide the flame retardant, titanium dioxide and fumed silica after being evenly stirred into two powders;

[0020] Step 3: Add one group of powders and curing agent to the coarse material A and stir to obtain coarse material B;

[0021] Step 4: Add another group of powders to the coarse material B and stir to mix, wherein the other group of powders is added gradually to obtain coarse material C;

[0022] Step 5: Add curing agent to the coarse material C, mix and stir, and obtain glue after stirring evenly;

[0023] Step 6: Apply the glue obtained in step 5 on the insulating base film with a thickness of 35um, and bake to obtain an insulating adhesive film.

[0024] As a further description of the above technical solution:

[0025] The method for manufacturing the double-sided adhesive film comprises the following steps:

[0026] Step S1: repeating steps 1 to 5 in the method for manufacturing a single-sided adhesive film to obtain glue;

[0027] Step S2: coating the glue obtained in step S1 on one side of the insulating base film with a thickness of 35 μm, and baking the glue, and rolling up the insulating base film after baking;

[0028] Step S3: coating the glue obtained in step S1 on the other side of the insulating base film with a thickness of 35 um, and baking the glue;

[0029] Step S4: After baking is completed and cooling is performed, the protective film is torn off to obtain a double-sided insulating film.

[0030] As a further description of the above technical solution:

[0031] The manufacturing materials of the protective film in step S2 include but are not limited to release film, release paper, and PP film.

[0032] As a further description of the above technical solution:

[0033] In the step 3, the stirring and mixing is carried out using a stirring tank, the speed of the stirring tank is 600R / min, and the stirring time is 15min. In the step 4, the mixing stirring tank has a speed of 600R / min and is stirred for 1h.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The raw materials used to manufacture the insulating film of the present invention are all conventional materials, which are simple and easy to obtain, and the manufacturing method is relatively simple, which is convenient for mass production of the insulating film;

[0036] 2. In addition, the present invention replaces the original main material epoxy resin with polyester, and adds titanium dioxide with a blue coloring base phase, so that the film is whiter in color compared with the prior art, achieving the effect of neutralizing yellowing. At the same time, the titanium dioxide with a blue base phase has a smaller particle size and good hiding performance, and can also cover part of the yellowing;

[0037] 3. Secondly, the insulating flame-retardant film of the present invention has good adhesion, flame retardancy, temperature resistance and good storage properties, and improves the yellowing resistance of the film, thereby avoiding yellowing of the film due to human factors in subsequent processing projects, reducing material waste and improving processing efficiency. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Embodiment 1:

[0040] The present invention provides a technical solution: a yellowing-resistant insulating flame-retardant adhesive film, comprising an insulating base film and an adhesive, wherein the adhesive is arranged above the insulating base film;

[0041] The manufacturing raw materials of the adhesive include main resin, epoxy resin, flame retardant, gas-phase silica, titanium dioxide, curing agent, catalyst and tackifying resin.

[0042] As a further description of the above technical solution:

[0043] The weight proportions of the raw materials for manufacturing the adhesive are: 90-100 parts of main resin, 0-10 parts of epoxy resin, 70-80 parts of flame retardant, 0-1 part of fumed silica, 2.5-10 parts of titanium dioxide, 1-10 parts of curing agent, 0.001-2 parts of catalyst and 0-10 parts of tackifying resin.

[0044] As a further description of the above technical solution:

[0045] The manufacturing materials of the insulating base film include but are not limited to PP film, PE film, PET film, and PI film.

[0046] As a further description of the above technical solution:

[0047] The coloring base phase of the titanium dioxide is blue, and the main resin is polyester. The titanium dioxide has different coloring base phases due to different particle sizes. When the average particle size of the titanium dioxide is less than 0.2μm, the titanium dioxide has a blue base phase, and when the average particle size is around 0.4μm, the titanium dioxide has a red base phase. In actual use, the titanium dioxide with a blue coloring base phase is relatively whiter.

[0048] Among them, the raw materials used to manufacture the insulating film of the present invention are all conventional materials, which are simple and easy to obtain, and the manufacturing method is relatively simple, which is convenient for mass production of the insulating film; and the present invention replaces the original main material epoxy resin with polyester, and by adding titanium dioxide with a blue coloring base phase, the film is whiter in color compared with the prior art, achieving the effect of neutralizing yellowing, and at the same time, the titanium dioxide with a blue base phase has a smaller particle size and good covering performance, and can also cover part of the yellowing; secondly, the insulating flame-retardant film of the present invention has good adhesion, flame retardant performance, temperature resistance and good storage performance, and improves the yellowing resistance of the film, avoids the yellowing of the film due to human factors in subsequent processing projects after the film is contaminated, reduces material waste, and improves processing efficiency.

[0049] Embodiment 2:

[0050] The weight proportions of the raw materials for manufacturing the adhesive are: 95 parts of main resin, 5 parts of epoxy resin, 75 parts of flame retardant, 0.5 parts of fumed silica, 6 parts of titanium dioxide, 5 parts of curing agent, 1 part of catalyst and 5 parts of tackifying resin.

[0051] Embodiment three:

[0052] The method for making a yellowing-resistant insulating flame-retardant adhesive film includes a single-sided adhesive film manufacturing method and a double-sided adhesive film manufacturing method.

[0053] As a further description of the above technical solution:

[0054] The manufacturing method of the single-sided adhesive film comprises the following steps:

[0055] Step 1: stirring and mixing the main resin, epoxy resin, catalyst and tackifying resin to obtain a crude material A;

[0056] Step 2: Mix and stir the flame retardant, titanium dioxide and fumed silica in the raw materials for manufacturing the processing adhesive, and divide the flame retardant, titanium dioxide and fumed silica after being evenly stirred into two powders;

[0057] Step 3: Add one group of powders and curing agent to the coarse material A and stir to obtain coarse material B;

[0058] Step 4: Add another group of powders to the coarse material B and stir to mix, wherein the other group of powders is added gradually to obtain coarse material C;

[0059] Step 5: Add curing agent to the coarse material C, mix and stir, and obtain glue after stirring evenly;

[0060] Step 6: Apply the glue obtained in step 5 on the insulating base film with a thickness of 35um, and bake to obtain an insulating adhesive film.

[0061] Among them, the manufacturing raw materials of the insulating flame retardant film are added and mixed in batches. This mixing method ensures uniform mixing on the one hand, and ensures that different component raw materials can be fully reacted during the mixing process on the other hand, which increases the flame retardant efficiency and insulation efficiency of the insulating flame retardant film to a certain extent, and can further prevent yellowing. When the materials are put in, the powder needs to be slowly introduced or poured in in batches to prevent the powder from sinking to the bottom and affecting the timely dispersion of the powder. The curing agent is added last because the curing agent contains a room temperature curing agent. If it is added last, it can avoid reactions during the dispersion process. Therefore, the curing agent is added after the glue is dispersed and before coating.

[0062] Embodiment 4:

[0063] The method for manufacturing the double-sided adhesive film comprises the following steps:

[0064] Step S1: repeating steps 1 to 5 in the method for manufacturing a single-sided adhesive film to obtain glue;

[0065] Step S2: coating the glue obtained in step S1 on one side of the insulating base film with a thickness of 35 μm, and baking the glue, and rolling up the insulating base film after baking;

[0066] Step S3: coating the glue obtained in step S1 on the other side of the insulating base film with a thickness of 35 um, and baking the glue;

[0067] Step S4: After baking is completed and cooling is performed, the protective film is torn off to obtain a double-sided insulating film.

[0068] The manufacturing materials of the protective film in step S2 include but are not limited to release film, release paper, and PP film.

[0069] In the step 3, the stirring and mixing is carried out by using a stirring tank, the speed of the stirring tank is 600R / min, and the stirring time is 15min. In the step 4, the speed of the mixing stirring tank is 600R / min, and the stirring time is 1h.

[0070] Among them, by changing the stirring rate and stirring time during the stirring and mixing process, uniform mixing and sufficient reaction can be ensured, and in the production process of double-sided adhesive films, the protective film made of release film, release paper, and PP film can prevent the adhesive from sticking to the machine during the secondary baking.

[0071] After the adhesive is disposed on the insulating base film to form a yellowing-resistant insulating flame-retardant adhesive film, its performance is tested. Before the performance test, the test specimen needs to be prepared. The test specimen preparation process includes the following steps:

[0072] Step A1: cutting a test specimen, wherein the size of the test specimen is 1 inch*30 cm;

[0073] Step A2: Lay the cut test specimens on the tinned copper plate in order;

[0074] Step A3: Use a hot press to hot press the test sample, and the hot pressing conditions are temperature 140° C., pressure 5 mPa, and hot pressing time 15 min.

[0075] When testing the test specimens, their stain resistance, peeling force, long-term temperature resistance, cold and hot shock peeling force and flame retardancy are tested. The peeling force test includes room temperature peeling force test, 105℃ peeling force test, 130℃ peeling force test, double 851000H peeling force and PCT24H peeling force test;

[0076] The test process of the above test specimen is as follows:

[0077] Anti-fouling performance test: simulate processing operation, the operator touches the component and the yellowing-resistant insulating flame-retardant film in turn, and observes the color change of the film;

[0078] Normal temperature peeling force test: Under the conditions of temperature 25℃ and humidity 40~60%RH, use a universal tensile machine to perform 180° peeling force test;

[0079] 105°C peeling force test: Use a high and low temperature tensile testing machine to place the test specimen at a temperature of 105°C for 30 minutes, and then use a high and low temperature tensile testing machine to perform a 180° peeling force test;

[0080] 130°C peeling force test: Use a high and low temperature tensile testing machine to place the test specimen at a temperature of 105°C for 30 minutes, and then use a high and low temperature tensile testing machine to perform a 180° peeling force test;

[0081] Long-term heat resistance test: The hot-pressed test specimens are bent at 90°C with an R angle of 2mm and a bending margin of 20mm. The bent test specimens are placed in a 130°C oven and baked for 72 hours. If there are no bulging or cracking problems, it is defined as good long-term heat resistance.

[0082] Thermal shock peeling strength test: Place the hot pressed peeling strength test specimens at -40℃-105℃ for 300 cycles, then return to room temperature and use a universal tensile testing machine to perform a 180° peeling strength test; the heating and cooling conditions are -40℃ / constant temperature for 1H, -40℃ to 105℃ / 0.5H, 105℃ / constant temperature for 1H, 105℃ down to -40℃ / 0.5H, 3 hours as one cycle;

[0083] Double 851000H peeling force test: Place the hot pressed peeling force test specimens at 85°C and 85%RH for 1000 hours, take out the samples, restore them to room temperature and dry them, and use a universal tensile machine to perform a 180° peeling force test;

[0084] PCT24H peeling force test: Place the hot pressed peeling force test specimens at 121°C, 100% RH, and 2 atm for 24 hours, take out the samples, restore them to room temperature and dry them, and use a universal tensile machine to perform a 180° peeling force test;

[0085] Flame retardant performance: The flame retardant grade of the film material is evaluated according to UL-94.

[0086] Table 1 below is a performance test table of embodiments of insulating flame-retardant adhesive films with different mass fractions. It can be seen from the table below that the insulating flame-retardant adhesive film manufactured by the present invention has obvious improvements in peeling force, yellowing resistance and flame retardancy.

[0087]

[0088] Table 1

[0089] By comparing Example 1 with Example 4, and Example 2 with Example 5, it can be seen that epoxy has a great influence on yellowing.

[0090] By comparing Example 3 with Example 4, and Example 5 with Example 6, it can be seen that the use of titanium dioxide with a blue base phase can improve the yellowing more significantly.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A yellowing-resistant insulating flame-retardant adhesive film, characterized in that: It includes an insulating base film and an adhesive, wherein the adhesive is arranged on the insulating base film; The manufacturing raw materials of the adhesive include main resin, epoxy resin, flame retardant, gas-phase silica, titanium dioxide, curing agent, catalyst and tackifying resin.

2. The yellowing-resistant insulating flame-retardant adhesive film according to claim 1, characterized in that: The weight proportions of the raw materials for manufacturing the adhesive are: 90-100 parts of main resin, 0-10 parts of epoxy resin, 70-80 parts of flame retardant, 0-1 part of fumed silica, 2.5-10 parts of titanium dioxide, 1-10 parts of curing agent, 0.001-2 parts of catalyst and 0-10 parts of tackifying resin.

3. The yellowing-resistant insulating flame-retardant adhesive film according to claim 1, characterized in that: The manufacturing materials of the insulating base film include but are not limited to PP film, PE film, PET film, and PI film.

4. The yellowing-resistant insulating flame-retardant adhesive film according to claim 1, characterized in that: The coloring base phase of the titanium dioxide is blue, and the main resin is polyester.

5. A method for manufacturing the yellowing-resistant insulating flame-retardant adhesive film according to claim 1, characterized in that: The method for making a yellowing-resistant insulating flame-retardant adhesive film includes a single-sided adhesive film manufacturing method and a double-sided adhesive film manufacturing method.

6. The method for manufacturing a yellowing-resistant insulating flame-retardant adhesive film according to claim 5, characterized in that: The manufacturing method of the single-sided adhesive film comprises the following steps: Step 1: stirring and mixing the main resin, epoxy resin, catalyst and tackifying resin to obtain a crude material A; Step 2: Mix and stir the flame retardant, titanium dioxide and fumed silica in the raw materials for manufacturing the processing adhesive, and divide the flame retardant, titanium dioxide and fumed silica after being evenly stirred into two powders; Step 3: Add one group of powders and curing agent to the coarse material A and stir to obtain coarse material B; Step 4: Add another group of powders to the coarse material B and stir to mix, wherein the other group of powders is added gradually to obtain coarse material C; Step 5: Add curing agent to the coarse material C, mix and stir, and obtain glue after stirring evenly; Step 6: Apply the glue obtained in step 5 on the insulating base film with a thickness of 35um, and bake to obtain an insulating adhesive film.

7. The method for manufacturing a yellowing-resistant insulating flame-retardant adhesive film according to claim 6, characterized in that: The method for manufacturing the double-sided adhesive film comprises the following steps: Step S1: repeating steps 1 to 5 in the method for manufacturing a single-sided adhesive film to obtain glue; Step S2: coating the glue obtained in step S1 on one side of the insulating base film with a thickness of 35 μm, and baking the glue, and rolling up the insulating base film after baking; Step S3: coating the glue obtained in step S1 on the other side of the insulating base film with a thickness of 35 um, and baking the glue; Step S4: After baking is completed and cooling is performed, the protective film is torn off to obtain a double-sided insulating film.

8. The method for manufacturing a yellowing-resistant insulating flame-retardant adhesive film according to claim 6, characterized in that: The manufacturing materials of the protective film in step S2 include but are not limited to release film, release paper, and PP film.

9. The method for manufacturing a yellowing-resistant insulating flame-retardant adhesive film according to claim 7, characterized in that: In the step 3, the stirring and mixing is carried out using a stirring tank, the speed of the stirring tank is 600R / min, and the stirring time is 15min. In the step 4, the mixing stirring tank has a speed of 600R / min and is stirred for 1h.

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