Fluorinated demolding belt and preparation method thereof

Abstract

The invention discloses a fluorinated demoulding belt which comprises two layers of thermal shrinkage plastic films, the two layers of thermal shrinkage plastic films are connected by arranging a bonding layer, and a release layer is arranged on the outer surface of at least one layer of thermal shrinkage plastic film. The invention further provides a preparation method of the fluorination demolding belt, the surface of the release layer is subjected to fluorination treatment through CF4 radio frequency capacitive coupling plasma, the radio frequency source power of the CF4 radio frequency capacitive coupling plasma is 150-250 W, the CF4 flow is 20-30 ml / min, and the treatment time is 5-10 min. The thermal shrinkage plastic film is used as the bottom film, the demolding belt is endowed with thermal shrinkage, the surface of a wrapping material is smooth and regular, meanwhile, fluorinated functional groups are grafted on a surface molecular chain, silicon transfer and silicon pollution of the demolding belt are reduced, the residual adhesion rate is increased, the repeated utilization rate of the demolding belt is increased, and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of release tapes, and particularly relates to a fluorinated release tape and a preparation method thereof. Background Art

[0002] Most of the insulation systems of generator stator bars adopt the process of low resin content vacuum pressure impregnation (VPI). The characteristic of the VPI process is that after the stator bar is impregnated with insulating paint, the curing of the insulating paint needs to be completed in a mold under high pressure and high temperature conditions. In order to prevent the bonding of the stator bar and the mold under high pressure and high temperature, a release tape is required to isolate the stator bar and the mold. Currently, a non-sticky polytetrafluoroethylene (PTFE) film tape is mainly used as the release tape. However, the relatively small release force and the inherent non-elastic characteristics of the PTFE material result in its inability to generate effective binding force and shrinkage force during the thermal curing process, leading to the formation of randomly distributed stress wrinkles on the surface of the cured insulating layer. Such microscopic structural defects may cause partial discharge and affect the uniformity of the main insulation performance. In addition, the high raw material cost of the PTFE film tape significantly increases the comprehensive cost in the process of motor manufacturing, which poses a challenge to the economy of large-scale production of large generator sets.

[0003] Chinese Patent Application No. CN202311295863.1 discloses a fluorosilicon release film. The release film includes a base film layer, a primer layer coated on both sides of the base film layer, and a fluorosilicon modified release layer coated on one side of the primer layer. The fluorosilicon modified release layer is prepared by coating a fluorosilicon modified release agent coating solution. The fluorosilicon modified release agent coating solution includes 100 parts of solvent, 1 - 5 parts of fluorosilicon modified main agent, 0.01 - 0.1 part of crosslinking agent, 0 - 1 part of controlling agent, and 0.01 - 0.2 part of platinum-based catalyst. Through the design of the formula, the adaptation to the base film, and the easily achievable thermal curing conditions, the release film of this invention has adjustable release force, low silicon transfer, high residual adhesion rate, and low surface roughness. However, due to the presence of fluorine-containing groups in this invention, the bonding force between the base film layer and the release layer is insufficient, which may cause the release layer to partially or completely peel off from the base film and directly adhere to the surface of the stator bar or the mold, resulting in incomplete peeling during demolding. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a fluorinated release tape and a preparation method thereof.

[0005] The technical solution of the present invention is as follows:

[0006] One of the purposes of the present invention is to provide a fluorinated release tape, which includes two layers of heat-shrinkable plastic films. The two layers of heat-shrinkable plastic films are connected by a bonding layer provided therebetween, and a release layer is provided on the outer surface of at least one layer of heat-shrinkable plastic film.

[0007] Another object of the present invention is to provide a method for preparing a fluorinated release tape, which uses CF4 radio frequency capacitive coupled plasma to perform fluorination treatment on the surface of the release layer. Among them, the radio frequency source power of the CF4 radio frequency capacitive coupled plasma is 150 - 250 W, the CF4 flow rate is 20 - 30 ml / min, and the treatment time is 5 - 10 min.

[0008] Further, the preparation method specifically includes the following steps:

[0009] S1: Add the silicone main agent and the crosslinking agent into a container, seal and stir for 5 min, add the solvent, inhibitor, anchoring agent, and peel force control agent, seal and stir for 5 min, and then add the catalyst. After sealing and stirring for 5 min, a silicone release agent is obtained; the stirring speed is 500 - 1000 r / min;

[0010] S2: Take two layers of heat-shrinkable plastic films, and uniformly coat the silicone release agent obtained in step S1 on at least one layer of heat-shrinkable plastic film by roll coating. After coating, put it into a drying oven for curing to form a release layer on the surface of the heat-shrinkable plastic film;

[0011] S3: Use a non-heat-shrinkable release film as the base material, coat a thermosetting adhesive on its surface, and heat it to complete curing to form an adhesive layer;

[0012] S4: Bond the other side of the heat-shrinkable plastic film with the release layer obtained in step S2 to the adhesive layer of the non-heat-shrinkable release film obtained in step S3. After bonding, remove the non-heat-shrinkable release film;

[0013] S5: Bond the heat-shrinkable plastic film obtained in step S4 to the other layer of heat-shrinkable plastic film obtained in step S2 through the adhesive layer, and then wind and slit it to obtain a release tape;

[0014] S6: Use CF4 radio frequency capacitive coupled plasma to perform fluorination treatment on the release layer of the release tape obtained in step S5 to obtain the fluorinated release tape.

[0015] Further, in step S1, the silicone release agent is composed of the following raw materials in parts by weight: 500 - 1000 parts of solvent, 100 parts of silicone main agent, 5 - 10 parts of crosslinking agent, 1 - 5 parts of catalyst, 0.03 - 0.15 parts of inhibitor, 1 - 5 parts of anchoring agent, and 30 - 50 parts of peel force control agent.

[0016] Further, the silicone main agent is vinyl silicone oil with a viscosity of 5000 - 10000 mPa·s, and the mass ratio of vinyl in the vinyl silicone oil is 0.1 - 0.2%; the crosslinking agent is side hydrogen-containing silicone oil with a viscosity of 50 - 80 mPa·s, and the mass ratio of hydrogen groups in the side hydrogen-containing silicone oil is 1 - 1.5%.

[0017] Further, the catalyst is a platinum catalyst with a platinum content of 0.1 - 0.5%; the inhibitor is one or a mixture of several of tetramethyltetravinylcyclotetrasiloxane, diallyl maleate, diallyl fumarate, 3,5 - dimethyl - 1 - hexyn - 3 - ol, and 3 - methyl - 1 - dodecyn - 3 - ol.

[0018] Further, the anchoring agent is one or a mixture of several of γ - glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, γ - aminopropyltriethoxysilane, and vinyltris(β - methoxyethoxy)silane; the peel force control agent is vinyl MQ silicone resin, and the mass ratio of vinyl in the vinyl MQ silicone resin is 1.2% - 1.4%.

[0019] Further, in step S2, the heat - shrinkable plastic film is pretreated by corona and then coated. The heat - shrinkable plastic film is a PET film or a PVC film with a thickness of 0.05 - 0.1 mm.

[0020] Further, in step S2, the coating amount of the silicone release agent is 0.8 - 1.2 g / m 2 , the temperature of the drying oven is 100 - 150 °C, the curing reaction time is 20 - 80 s, and the thickness of the release layer is 0.0005 - 0.002 mm.

[0021] Further, the adhesive layer is one or a mixture of several of polyurethane glue, phenolic glue, and acrylate - based pressure - sensitive glue, and the thickness of the cured adhesive layer is 0.005 - 0.01 mm.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The preparation method of a fluorinated release tape provided by the present invention uses CF4 radio - frequency capacitive - coupled plasma to perform fluorination modification on the surface of the release layer of the release tape. By grafting fluorinated functional groups on the surface molecular chains, the silicon transfer and silicon pollution of the release tape can be reduced, the residual adhesion rate can be improved, thereby increasing the reuse rate of the release tape and reducing costs. At the same time, since plasma fluorination only occurs on the surface of the material, the adhesion between the release layer and the heat - shrinkable plastic film in the release tape will not be reduced. Therefore, the release tape prepared by the present invention has better residual adhesion rate, adhesion performance, and peeling performance at the same time.

[0024] 2. The fluorinated release tape provided by the present invention has a high release force and good integrity. By setting the heat - shrinkable plastic film as the base film, the release tape gives a regular shrinkage force to the wrapped material at a certain temperature, so that the surface of the wrapped material is smoother and more regular. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 In the present invention, it is a schematic structural view of the fluorinated release tape provided in Embodiment 1;

[0026] Figure 2 In the present invention, it is a schematic structural view of the fluorinated release tape provided in Embodiment 2.

[0027] In the figure, 1 is a heat-shrinkable plastic film; 2 is an adhesive layer; 3 is a release layer. Detailed implementation manners

[0028] The following combines with preferred embodiments and combines with the attached Figure 1-2 , and further describes the present invention. In the present invention, the endpoints and any values of the disclosed ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values; for numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article; the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels without special instructions; the experimental methods in the following embodiments are conventional methods without special instructions.

[0029] Embodiment 1

[0030] This embodiment provides a fluorinated release tape. As Figure 1 shown, it includes two layers of heat-shrinkable plastic films 1. The two layers of heat-shrinkable plastic films 1 are connected by arranging an adhesive layer 2 therebetween, and a release layer 3 is arranged on the outer surface of one of the heat-shrinkable plastic films 1.

[0031] This embodiment also provides a preparation method of the above-mentioned fluorinated release tape, including the following steps:

[0032] S1: Add an organosilicon main agent and a crosslinking agent into a container, seal and stir for 5 min, add a solvent, an inhibitor, an anchoring agent, and a release force control agent, seal and stir for 5 min, and then add a catalyst, and obtain an organosilicon release agent after sealing and stirring for 5 min; the stirring speed is 500 r / min;

[0033] S2: Take two layers of heat-shrinkable plastic films 1, and uniformly coat the organosilicon release agent obtained in step S1 on one of the heat-shrinkable plastic films 1 by roll coating. After coating, put it into a drying oven for curing to form a release layer 3 on the surface of the heat-shrinkable plastic film 1; the heat-shrinkable plastic film is a PET film with a thickness of 0.05 mm;

[0034] In this embodiment, the coating amount of the organosilicon release agent is 0.8 g / m 2, the temperature of the drying oven is 150° C., the time of the curing reaction is 60 seconds, and the thickness of the release layer 3 is 0.0005 mm; in this embodiment, the heat-shrinkable plastic film is pre-treated by corona treatment before coating;

[0035] S3: Using a non-heat-shrinkable release film as a substrate, coating a thermosetting adhesive on its surface, and heating it until it is completely cured to form an adhesive layer 2;

[0036] In this embodiment, the adhesive layer 2 is polyurethane glue, and the thickness of the adhesive layer 2 after curing is 0.005 mm.

[0037] S4: Laminating the other side of the heat-shrinkable plastic film 1 having the release layer 3 in step S2 with the adhesive layer 2 of the non-heat-shrinkable release film obtained in step S3, and peeling off the non-heat-shrinkable release film after laminating;

[0038] S5: bonding the heat-shrinkable plastic film 1 obtained in step S4 to another layer of heat-shrinkable plastic film 1 in step S2 through the adhesive layer 2, and rolling and slitting to obtain a release tape;

[0039] S6: using CF4 radio frequency capacitively coupled plasma to perform fluorination treatment on the release layer 3 of the release tape obtained in step S5 to obtain the fluorinated release tape.

[0040] In this embodiment, the RF source power of the CF4 RF capacitively coupled plasma is 250 W, the CF4 flow rate is 30 ml / min, and the processing time is 10 min.

[0041] In this embodiment, the organic silicone release agent is composed of the following raw materials in parts by weight: 500 parts of solvent, 100 parts of organic silicone main agent, 10 parts of cross-linking agent, 1 part of catalyst, 0.15 parts of inhibitor, 5 parts of anchoring agent, and 50 parts of peeling force control agent.

[0042] In this embodiment, the silicone main agent is vinyl silicone oil, specifically the product with the model number HD-FV5000 produced by Hengda Chemical Industry Company, with a viscosity of 5000 mPa·s. The mass ratio of vinyl in the vinyl silicone oil is 0.13 - 0.19%; the cross-linking agent is side hydrogen-containing silicone oil, specifically the product with the model number RH-H512 of Ningbo Runhe New Materials Technology Co., Ltd., with a viscosity of 50 - 65 mPa·s. The mass ratio of hydrogen groups in the side hydrogen-containing silicone oil is 1.15 - 1.25%; the catalyst is a platinum catalyst with a platinum content of 0.1 - 0.5%, specifically the product with the model number ACS-Pt-50 produced by Shanghai Xibao New Materials Co., Ltd.; the inhibitor is 3-methyl-1-dodecyn-3-ol; the anchoring agent is the product with the model number SYL-OFF SL 9250 produced by Dow Chemical Company, and its main component is γ-glycidoxypropyltrimethoxysilane; the peel force control agent is vinyl MQ silicone resin, and the mass ratio of vinyl in the vinyl MQ silicone resin is 1.2% - 1.4%, specifically the product with the model number CX-355-2 produced by Chenxi Company.

[0043] Example 2

[0044] This embodiment provides a fluorinated release tape, as Figure 2 shown, which includes two layers of heat-shrinkable plastic films 1. The two layers of heat-shrinkable plastic films 1 are connected by a bonding layer 2 provided therebetween, and release layers 3 are provided on the outer surfaces of the two layers of heat-shrinkable plastic films 1.

[0045] This embodiment also provides a preparation method of the above-mentioned fluorinated release tape, including the following steps:

[0046] S1: Add the silicone main agent and the cross-linking agent into a container, seal and stir for 5 min, add the solvent, inhibitor, anchoring agent, and peel force control agent, seal and stir for 5 min, and then add the catalyst. After sealing and stirring for 5 min, a silicone release agent is obtained; the stirring speed is 1000 r / min;

[0047] S2: Take two layers of heat-shrinkable plastic films 1, and uniformly coat the silicone release agent obtained in step S1 on the two layers of heat-shrinkable plastic films 1 by roll coating. After coating, put it into a baking oven for curing to form a release layer 3 on the surface of the heat-shrinkable plastic film 1;

[0048] In this embodiment, corona treatment is also used to pretreat the heat-shrinkable plastic film 1 before coating; the heat-shrinkable plastic film 1 is a PET film with a thickness of 0.075 mm; the coating amount of the silicone release agent is 1 g / m 2 , the temperature of the baking oven is 150 °C, the curing reaction time is 60 s, and the thickness of the release layer 3 is 0.001 mm;

[0049] S3: Using a non-shrinkable release film as the substrate, coat a thermosetting adhesive on its surface, and heat it to complete curing after coating to form the adhesive layer 2;

[0050] In this embodiment, the adhesive layer 2 is a polyurethane adhesive, and the thickness of the cured adhesive layer 2 is 0.008 mm.

[0051] S4: Bond the other side of the shrinkable plastic film 1 with the release layer 3 in step S2 to the adhesive layer 2 of the non-shrinkable release film obtained in step S3, and remove the non-shrinkable release film after bonding;

[0052] S5: Bond the shrinkable plastic film 1 obtained in step S4 to the other shrinkable plastic film 1 in step S2 through the adhesive layer 2, and then wind and slit it to obtain the release tape;

[0053] S6: Use CF4 radio frequency capacitive coupling plasma to fluorinate the release layer 3 of the release tape obtained in step S5 to obtain the fluorinated release tape.

[0054] The structural schematic diagram of the fluorinated release tape prepared in this embodiment is as Figure 2 shown.

[0055] In this embodiment, the radio frequency source power of the CF4 radio frequency capacitive coupling plasma is 150 W, the CF4 flow rate is 20 ml / min, and the treatment time is 5 min.

[0056] In this embodiment, the silicone release agent is composed of the following raw materials in parts by weight: 500 parts of solvent, 100 parts of silicone main agent, 5 parts of cross-linking agent, 5 parts of catalyst, 0.15 part of inhibitor, 5 parts of anchoring agent, and 50 parts of peel force control agent.

[0057] In this embodiment, the silicone main agent is vinyl silicone oil, specifically the product with the model number HD-FV5000 produced by Hengda Chemical Industry Company, with a viscosity of 5000 mPa·s. The mass ratio of vinyl in the vinyl silicone oil is 0.13 - 0.19%; the cross-linking agent is side hydrogen-containing silicone oil, specifically the product with the model number RH-H512 of Ningbo Runhe New Materials Technology Co., Ltd., with a viscosity of 50 - 65 mPa·s. The mass ratio of hydrogen groups in the side hydrogen-containing silicone oil is 1.15 - 1.25%; the catalyst is a platinum catalyst with a platinum content of 0.1 - 0.5%, specifically the product with the model number ACS-Pt-50 produced by Shanghai Xibao New Materials Co., Ltd.; the inhibitor is 3-methyl-1-dodecyn-3-ol; the anchoring agent is the product with the model number 9250 produced by Dow Chemical Company; the peel force control agent is vinyl MQ silicone resin, and the mass ratio of vinyl in the vinyl MQ silicone resin is 1.2% - 1.4%, specifically the product with the model number CX-355-2 produced by Chenxi Company.

[0058] Example 3

[0059] This embodiment provides a fluorinated release tape, which includes two layers of heat-shrinkable plastic films. The two layers of heat-shrinkable plastic films are connected by a bonding layer provided therebetween, and a release layer is provided on the outer surface of one of the heat-shrinkable plastic films.

[0060] This embodiment also provides a preparation method of the above-mentioned fluorinated release tape, which includes the following steps:

[0061] S1: Add the silicone main agent and the cross-linking agent into a container, seal and stir for 5 min, add the solvent, inhibitor, anchoring agent, and peel force control agent, seal and stir for 5 min, and then add the catalyst. After sealing and stirring for 5 min, a silicone release agent is obtained; the stirring speed is 800 r / min for all;

[0062] S2: Take two layers of heat-shrinkable plastic films, and uniformly coat the silicone release agent obtained in step S1 on at least one layer of heat-shrinkable plastic film by roll coating. After coating, put it into a drying oven for curing to form a release layer on the surface of the heat-shrinkable plastic film;

[0063] In this embodiment, corona treatment is also used to pretreat the heat-shrinkable plastic film before coating; the heat-shrinkable plastic film is a PET film with a thickness of 0.1 mm; the coating amount of the silicone release agent is 1.2 g / m 2 , the temperature of the drying oven is 150 °C, the curing reaction time is 60 s, and the thickness of the release layer is 0.002 mm;

[0064] S3: Using a non-heat-shrinkable release film as the substrate, coat a thermosetting adhesive on its surface, and heat it to complete curing after coating to form a bonding layer;

[0065] In this embodiment, the adhesive layer is a mixture of phenolic resin adhesive and acrylate pressure-sensitive adhesive, and the thickness of the cured adhesive layer is 0.01 mm.

[0066] S4: Attach the other side of the heat-shrinkable plastic film with the release layer in Step S2 to the adhesive layer of the non-heat-shrinkable release film obtained in Step S3. After attachment, remove the non-heat-shrinkable release film.

[0067] S5: Bond the heat-shrinkable plastic film obtained in Step S4 to the other layer of heat-shrinkable plastic film in Step S2 through the adhesive layer, and then wind and slit it to obtain the release tape.

[0068] S6: Treat the release layer of the release tape obtained in Step S5 with CF4 radio frequency capacitive coupling plasma to obtain the fluorinated release tape.

[0069] In this embodiment, the radio frequency source power of the CF4 radio frequency capacitive coupling plasma is 200 W, the CF4 flow rate is 25 ml / min, and the treatment time is 8 min.

[0070] In this embodiment, the silicone release agent is composed of the following raw materials in parts by weight: 500 parts of solvent, 100 parts of silicone main agent, 10 parts of cross-linking agent, 3 parts of catalyst, 0.15 part of inhibitor, 1 part of anchoring agent, and 50 parts of peel force control agent.

[0071] In this embodiment, the silicone main agent is vinyl silicone oil, specifically the product with the model HD-FV5000 produced by Hengda Chemical Co., Ltd., with a viscosity of 5000 mPa·s. The mass ratio of vinyl in the vinyl silicone oil is 0.13 - 0.19%; the cross-linking agent is side hydrogen-containing silicone oil, specifically the product with the model RH-H512 produced by Ningbo Runhe High-Tech Materials Co., Ltd., with a viscosity of 50 - 65 mPa·s. The mass ratio of hydrogen in the side hydrogen-containing silicone oil is 1.15 - 1.25%; the catalyst is a platinum catalyst with a platinum content of 0.1 - 0.5%, specifically the product with the model ACS-Pt-50 produced by Shanghai Xibao High-Tech Materials Co., Ltd.; the inhibitor is 3-methyl-1-dodecyne-3-ol; the anchoring agent is the product with the model 9250 produced by Dow Chemical Company; the peel force control agent is vinyl MQ silicone resin, and the mass ratio of vinyl in the vinyl MQ silicone resin is 1.2% - 1.4%, specifically the product with the model CX-355-2 produced by Chenxi Company.

[0072] Example 4

[0073] Basically the same as Example 1, except that in the silicone release agent of this example, the stripping force control agent is 30 parts. In the preparation method provided in this example, the heat-shrinkable plastic film in step S2 is a PVC film.

[0074] Example 5

[0075] Basically the same as Example 1, except that in the preparation method provided in this example, in step S2, the coating amount of the silicone release agent is 1.2 g / m 2 , the temperature of the drying oven is 100 °C, the heat-shrinkable plastic film is a PVC film, and the thickness is 0.075 mm.

[0076] Example 6

[0077] Basically the same as Example 1, except that in the preparation method provided in this example, in step S2, the heat-shrinkable plastic film is a PVC film with a thickness of 0.1 mm; in step S6, the RF source power of the CF4 radio frequency capacitive coupling plasma is 150 W, the CF4 flow rate is 20 ml / min, and the treatment time is 5 min.

[0078] Example 7

[0079] Basically the same as Example 1, except that the silicone release agent in this example is composed of the following raw materials in parts by weight: 1000 parts of solvent, 100 parts of silicone main agent, 8 parts of cross-linking agent, 5 parts of catalyst, 0.03 part of inhibitor, 3 parts of anchoring agent, and 20 parts of stripping force control agent. In the preparation method provided in this example, in step S2, the coating amount of the silicone release agent is 1 g / m 2 , the temperature of the drying oven is 120 °C, and the curing reaction time is 80 s.

[0080] Example 8

[0081] Basically the same as Example 1, except that the silicone release agent in this example is composed of the following raw materials in parts by weight: 800 parts of solvent, 100 parts of silicone main agent, 5 parts of cross-linking agent, 5 parts of catalyst, 0.1 part of inhibitor, 5 parts of anchoring agent, and 50 parts of stripping force control agent. In the preparation method provided in this example, in step S2, the heat-shrinkable plastic film is not pretreated by corona.

[0082] In this embodiment, the silicone main agent can also be selected from other vinyl silicone oils with a viscosity of 5000-10000 mPa·s and a vinyl mass fraction of 0.1-0.2%; the cross-linking agent can also be selected from other side hydrogen-containing silicone oils with a viscosity of 50-80 mPa·s and a hydrogen mass fraction of 1-1.5%; the catalyst can also be selected from other platinum catalysts with a platinum content of 0.1-0.5%; the inhibitor can also be selected from one or a mixture of several of tetramethyltetravinylcyclotetrasiloxane, diallyl maleate, diallyl fumarate, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-dodecyn-3-ol; the anchoring agent can also be selected from one or a mixture of several of γ-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltris(β-methoxyethoxy)silane; the peel force control agent can also be selected from other vinyl MQ silicone resins with a vinyl mass fraction of 1.2%-1.4%.

[0083] Comparative Example 1

[0084] The difference from Example 1 is that in step S6 of the preparation method provided in this comparative example, the release layer obtained in step S2 was not fluorinated using CF4 radio frequency capacitive coupling plasma.

[0085] Comparative Example 2

[0086] The difference from Example 1 is that in step S6 of the preparation method provided in this comparative example, the radio frequency source power of the CF4 radio frequency capacitive coupling plasma is 100 W, the CF4 flow rate is 10 ml / min, and the treatment time is 1 min.

[0087] Comparative Example 3

[0088] The difference from Example 1 is that the release tape in this comparative example is a PTFE film.

[0089] Evaluation of implementation effect

[0090] The following is a specific test on the release tapes prepared in Examples 1-8 and Comparative Examples 1-3 to further illustrate the excellent effects achieved by the present invention:

[0091] 180° peel force test: Tested using a tensile testing machine according to the method for release films of optical functional films in GB / T 25256-2010, with a peel rate of 300 mm / min, testing the conventional release force, aged release force, and residual adhesion rate. The test results are shown in the following table:

[0092] Table 1 Statistical table of 180° peel force test results

[0093]

[0094] As can be seen from the above table, the release tapes prepared in Examples 1-8 of the present invention all have a relatively large release force, which is mainly affected by the performance of the release agent, the curing time, and the coating amount. At the same time, the release tapes prepared in Examples 1-8 of the present invention have a relatively high residual adhesion rate, which proves that the prepared release tapes have excellent anti-silicon transfer and anti-silicon pollution capabilities.

[0095] As can be seen from the experimental data of Example 1 and Comparative Example 1, after introducing fluorine functional groups on the surface of the release agent by CF4 radio frequency capacitive coupling plasma treatment, the release force of the release tape will decrease to a certain extent, but still remains at a relatively high level, and can be applied to the release of the main insulation curing of large motors. At the same time, in Example 1, by introducing fluorine functional groups, the residual adhesion rate was effectively increased, and the anti-silicon transfer and anti-silicon pollution capabilities of the release tape were improved.

[0096] As can be seen from the experimental data of Example 1 and Comparative Example 2, the CF4 radio frequency capacitive coupling plasma treatment process will affect the fluorination effect, and low radio frequency source power, CF4 flow rate, and treatment time will lead to fluorination failure.

[0097] As can be seen from the experimental data of Example 1 and Comparative Example 3, due to the low surface energy of the PTFE film itself, it has a low release force as a release tape. However, during the curing process of the insulating material, thermal expansion and contraction or chemical reactions will generate shrinkage stress, and the sliding or expansion of the internal material will cause interlayer misalignment. The release tape with a low release force cannot give the insulating material surface a uniform binding force, making it easy for the material surface to appear wrinkled. At the same time, since there is no release agent on the surface of the PTFE film, there is no silicon transfer and silicon pollution when it is used as a release tape, and it has a high residual adhesion rate.

[0098] Thermal shrinkage test: Using a heat shrinkage tester, the test was carried out according to the test standard of GB / T 34848-2017 "Test Method for Shrinkage Performance of Heat Shrinkable Films", and the temperature was set at 150 °C. The test results are shown in the following table:

[0099] Table 2 Statistical table of 150 °C thermal shrinkage performance test results

[0100]

[0101]

[0102] As can be seen from the above table, the release tapes prepared in Examples 1-8 of the present invention all have a certain shrinkage performance. Compared with the traditional PTFE release tape, it is mainly affected by the thickness and type of the heat shrinkable plastic film.

[0103] As can be seen from the experimental data of Example 1 and Comparative Example 1, when the thickness and type of the heat shrinkable plastic film remain unchanged, the transverse shrinkage rate remains unchanged.

[0104] It can be seen from the experimental data of Example 1 and Comparative Example 2 that when the thickness and type of the heat-shrinkable plastic film remain unchanged, the transverse shrinkage rate remains unchanged.

[0105] It can be seen from the experimental data of Example 1 and Comparative Example 3 that using a heat-shrinkable plastic film as the base film of the demoulding tape can effectively increase the transverse shrinkage rate of the demoulding tape. Compared with the PTFE demoulding tape, it can effectively impart a regular shrinkage force to the wrapping material, which is beneficial to maintaining the flatness and regularity of the insulating material on the surface of the stator coil.

[0106] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A fluorinated release tape, characterized in that, It includes two layers of heat-shrinkable plastic films (1), which are connected by a bonding layer (2) disposed therebetween, and a release layer (3) is disposed on the outer surface of at least one layer of the heat-shrinkable plastic film (1).

2. The preparation method of a fluorinated release tape according to claim 1, characterized in that, The surface of the release layer (3) is fluorinated using CF4 radio frequency capacitive coupled plasma. Among them, the radio frequency source power of the CF4 radio frequency capacitive coupled plasma is 150 - 250 W, the CF4 flow rate is 20 - 30 ml / min, and the treatment time is 5 - 10 min.

3. The preparation method of a fluorinated demoulding tape according to claim 2, characterized in that, Specifically, it includes the following steps: S1: Add silicone main agent and crosslinking agent into a container, seal and stir for 5 min, add solvent, inhibitor, anchoring agent, and peel force control agent, seal and stir for 5 min, and then add catalyst, seal and stir for 5 min to obtain a silicone release agent; the stirring speed is 500 - 1000 r / min; S2: Take two layers of heat-shrinkable plastic films (1), and uniformly coat the silicone release agent obtained in step S1 on at least one layer of the heat-shrinkable plastic film (1) by roll coating. After coating, put it into a drying oven for curing to form a release layer (3) on the surface of the heat-shrinkable plastic film (1); S3: Use a non-heat-shrinkable release film as the substrate, coat a thermosetting adhesive on its surface, and heat it to complete curing to form a bonding layer (2); S4: Bond the other side of the heat-shrinkable plastic film (1) with the release layer (3) in step S2 to the bonding layer (2) of the non-heat-shrinkable release film obtained in step S3, and remove the non-heat-shrinkable release film after bonding; S5: Bond the heat-shrinkable plastic film (1) obtained in step S4 with the other layer of the heat-shrinkable plastic film (1) in step S2 through the bonding layer (2), and then wind and slit it to obtain a release tape; S6: Use CF4 radio frequency capacitive coupled plasma to fluorinate the release layer (3) of the release tape obtained in step S5 to obtain the fluorinated release tape.

4. The preparation method of a fluorinated release tape according to claim 3, characterized in that, In step S1, the silicone release agent is composed of the following raw materials in parts by weight: 500 - 1000 parts of solvent, 100 parts of silicone main agent, 5 - 10 parts of crosslinking agent, 1 - 5 parts of catalyst, 0.03 - 0.15 parts of inhibitor, 1 - 5 parts of anchoring agent, and 30 - 50 parts of peel force control agent.

5. The preparation method of a fluorinated release tape according to claim 4, characterized in that, The silicone main agent is vinyl silicone oil with a viscosity of 5000 - 10000 mPa·s, and the mass ratio of vinyl in the vinyl silicone oil is 0.1 - 0.2%; the crosslinking agent is side hydrogen-containing silicone oil with a viscosity of 50 - 80 mPa·s, and the mass ratio of hydrogen groups in the side hydrogen-containing silicone oil is 1 - 1.5%.

6. The preparation method of a fluorinated release tape according to claim 4, characterized in that, The catalyst is a platinum catalyst with a platinum content of 0.1 - 0.5%; the inhibitor is one or a mixture of tetramethyltetravinylcyclotetrasiloxane, diallyl maleate, diallyl fumarate, 3,5-dimethyl-1-hexynyl-3-ol, 3-methyl-1-dodecyn-3-ol.

7. The preparation method of a fluorinated release tape according to claim 4, characterized in that, The anchoring agent is one or a mixture of γ-glycidyl ether oxypropyltrimethoxysilane, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltri-(β-methoxyethoxy)silane; the peel force control agent is vinyl MQ silicone resin, and the mass ratio of vinyl in the vinyl MQ silicone resin is 1.2%-1.4%.

8. The preparation method of a fluorinated release tape according to claim 3, characterized in that, In step S2, the heat-shrinkable plastic film (1) is pretreated by corona and then coated. The heat-shrinkable plastic film (1) is a PET film or a PVC film with a thickness of 0.05-0.1 mm.

9. The preparation method of a fluorinated release tape according to claim 3, characterized in that In step S2, the coating amount of the silicone release agent is 0.8 - 1.2 g / m 2 , the temperature of the drying oven is 100 - 150 °C, the time of the curing reaction is 20 - 80 s, and the thickness of the release layer (3) is 0.0005 - 0.002 mm.

10. The preparation method of a fluorinated release tape according to claim 3, characterized in that, The adhesive layer (2) is one or a mixture of polyurethane glue, phenolic glue, and acrylate pressure-sensitive glue, and the thickness of the cured adhesive layer (2) is 0.005-0.01 mm.

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