A breathable release packaging film and a preparation method and application thereof

Abstract

This application relates to the field of release film technology, specifically providing a breathable release packaging film, its preparation method, and its application. The breathable release packaging film comprises, from top to bottom, a silicone oil layer and a base film consisting of a top layer, a middle layer, and a bottom layer. The thickness of the base film is 0.02-0.05 mm. The breathable release packaging film has pinhole structures with a diameter of 0.2-1.5 mm. By optimizing the raw material composition, type, and dosage of the top, middle, and bottom layers, the heat resistance of the packaging film can be increased to 125-135℃. Further optimization of the preparation process and the raw material composition of the silicone oil layer can improve the release effect of the product. The prepared breathable release packaging film has mechanical properties that allow for automatic spreading by a robotic arm, improving the automation level of the packaging process. When used for packaging molten hot melt adhesives, it does not exhibit problems such as heat deformation, perforation, burns, or cracking, and has good heat-sealing and packaging performance.

Description

Technical Field

[0001] This invention relates to the field of release film technology, C08L23 / 06, and particularly to a breathable release packaging film, its preparation method, and its application. Background Technology

[0002] To facilitate storage and transportation, a release film is currently manually laid inside the cardboard box when loading molten hot melt adhesive. However, manual film laying is inefficient. Therefore, inventing a release film that can be automatically laid out using a robotic arm to improve the packaging efficiency of hot melt adhesive is of great significance. Furthermore, existing release films have poor heat resistance, easily leading to heat deformation, perforation, and film cracking when packaging molten hot melt adhesive, as well as the problem of non-release in the gusseted area. These issues still need to be addressed.

[0003] Chinese patent CN117227292A discloses a high-barrier biaxially oriented polyethylene film, its preparation method, and its application. This patent sequentially comprises a substrate layer, a barrier layer, and a puncture-resistant layer. The substrate layer is made of low-density polyethylene, metallocene polyethylene, and a compatibilizer. The barrier layer is made of modified polyethylene terephthalate, high-density polyethylene, and an anti-adhesion agent. The puncture-resistant layer is made of low-density polyethylene, an elastomer, and nylon resin. The aforementioned high-barrier biaxially oriented polyethylene film can be used in liquid packaging and flexible packaging. Its layer structure solves the problems of heat resistance and gas barrier properties of polyethylene films, and it is easy to stretch and not easily broken. However, when used as a release film, its release effect is poor. Chinese patent CN111825908B discloses a modified film for hot melt adhesive packaging and its preparation method. The film raw materials of this patent include POE with a melting point below 100℃, PE with a melting point of 100-130℃, anti-blocking agents, slip agents, and anti-aging agents. The prepared film can melt quickly together with hot melt adhesive, reducing the adhesion loss of hot melt adhesive without affecting the performance of hot melt adhesive. However, this patent does not pay attention to the release effect of the film and the problem of film cracking. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention first provides a breathable release packaging film, wherein the breathable release packaging film comprises, from top to bottom, a silicone oil layer and a base film composed of a top layer, a middle layer and a bottom layer, wherein the thickness of the base film is 0.02-0.05 mm, preferably 0.02-0.03 mm.

[0005] Furthermore, the thickness of the surface layer is 20-40% of the thickness of the base film, preferably 25-35%, and more preferably 30%.

[0006] Furthermore, the thickness of the intermediate layer is 30-50% of the thickness of the base film, preferably 35-45%, and more preferably 40%.

[0007] Furthermore, the thickness of the bottom layer is 20-40% of the thickness of the base film, preferably 25-35%, and more preferably 30%.

[0008] Furthermore, based on the total mass of the raw materials used to prepare the surface layer, the raw materials for preparing the surface layer include 65-85% high-density polyethylene, 5-22% linear low-density polyethylene, and 3-15% polyolefin elastomer.

[0009] Preferably, based on the total mass of the raw materials for preparing the surface layer, the raw materials for preparing the surface layer include 75-82% high-density polyethylene, 5-15% linear low-density polyethylene, and 5-13% polyolefin elastomer.

[0010] Furthermore, the raw materials for preparing the surface layer also include 0.1-5% antistatic agent, preferably 1-3% antistatic agent.

[0011] Furthermore, the antistatic agent is selected from at least one of anionic antistatic agents, cationic antistatic agents, nonionic antistatic agents, amphoteric antistatic agents, and permanent antistatic agents, preferably a permanent antistatic agent.

[0012] Furthermore, the permanent antistatic agent includes, but is not limited to, at least one of polyethylene oxide, polyether ester amide, and polyether ester imide.

[0013] Furthermore, based on the total mass of the raw materials for preparing the intermediate layer, the raw materials for preparing the intermediate layer include 70-95% high-density polyethylene and 5-30% linear low-density polyethylene.

[0014] Preferably, based on the total mass of the raw materials for preparing the middle layer, the raw materials for preparing the middle layer include 80-90% high-density polyethylene and 10-20% linear low-density polyethylene.

[0015] Furthermore, based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer include 80-95% high-density polyethylene, 1-12% linear low-density polyethylene, and 1-10% polyolefin elastomer.

[0016] Preferably, based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer include 86-92% high-density polyethylene, 2-8% linear low-density polyethylene, and 3-7% polyolefin elastomer.

[0017] This application controls the release packaging film to include three layers of polyethylene film and strictly specifies the type and amount of raw materials for each layer. The combined effect of the three layers can improve the temperature resistance of the release packaging film to above 125℃, preferably 125-135℃, achieving good packaging of molten hot melt adhesive. High-density polyethylene has very high crystallinity, which can significantly improve the high-temperature resistance of the release packaging film. However, its high molecular weight and low melt flow rate result in poor processing dispersion, easily leading to uneven system dispersion and unstable temperature resistance and mechanical properties of the release packaging film. Blending a certain amount of linear low-density polyethylene and polyolefin elastomer can improve these problems. Linear low-density polyethylene has many short branches but no long branches, resulting in lower crystallinity, which is beneficial for improving the toughness of the release packaging film. However, excessive addition can lead to a decrease in the heat resistance of the release packaging film, causing the film layers to stick together and become inseparable during coating. Polyolefin elastomers can assist linear low-density polyethylene and high-density polyethylene in forming excellent molecular crosslinking and active states. By regulating the melt flow rate, viscosity and tensile modulus of the above three materials, their molecular weight and molecular chain length can be indirectly controlled, so that their blend system and release packaging film have suitable Tp values, improve the temperature resistance of the release packaging film, and avoid product burns or perforations when loading hot melt adhesive.

[0018] Furthermore, in the top layer, middle layer, and bottom layer described above, the melt flow rate of the high-density polyethylene at 190°C and 2.16 kg is 0.04-0.8 g / 10 min.

[0019] Furthermore, the melt mass flow rate of the linear low-density polyethylene at 190°C and 2.16 kg is 1-2 g / 10 min, preferably 1-1.5 g / 10 min, and more preferably 1 g / 10 min.

[0020] Furthermore, the melting temperature of the linear low-density polyethylene is 110-130℃, preferably 115-123℃.

[0021] Furthermore, the Mooney viscosity of the polyolefin elastomer at 121°C is 45-58 MU, preferably 50-56 MU.

[0022] Furthermore, the tensile modulus of the polyolefin elastomer is 1-4.5 MPa, preferably 2-4 MPa.

[0023] Furthermore, based on the mass of vinyl silicone oil as 100%, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.6-0.9% hydrogen-containing silicone oil crosslinking agent, 1.0-1.6% catalyst, 0-1% anchoring agent, and 200-600% solvent.

[0024] Furthermore, the solvent includes, but is not limited to, at least one of methyl ethyl ketone (MEK), isopropanol, and 120-octane gasoline, preferably 120-octane gasoline.

[0025] Furthermore, the catalyst is chloroplatinic acid.

[0026] Furthermore, the mass ratio of the hydrogen-containing silicone oil crosslinking agent to the catalyst is 0.7-0.8:1.2-1.4. The chloroplatinic acid catalyst can catalyze the crosslinking agent to enhance the curing effect of the silicone oil. With increasing amounts of catalyst and dry silicone, the peel force of the release film decreases, and the residual adhesion rate increases. However, the curing effect of the silicone oil is optimal when the mass ratio of the hydrogen-containing silicone oil crosslinking agent to the catalyst is 0.7-0.8:1.2-1.4.

[0027] Furthermore, the breathable release packaging film is provided with pinhole structures with a diameter of 0.2-1.5 mm; preferably, the diameter of the pinhole structures is 0.5-1.0 mm.

[0028] Furthermore, the dry silica content of the breathable release film is 0.2-0.5 g / m³. 2 Preferably, it is 0.3-0.4 g / m 2 .

[0029] Secondly, this application also provides a method for preparing the breathable release packaging film, including the following steps:

[0030] S1. The raw materials for the preparation of the top layer, middle layer and bottom layer are mixed separately and then subjected to three-layer co-extrusion blow molding to form a cylindrical film;

[0031] S2. Double-sided corona treatment of the cylindrical membrane;

[0032] S3. Apply silicone oil to both sides of the diaphragm in sequence;

[0033] S4. After punching holes in the tubular film, fold it into an accordion structure and cut the bag.

[0034] The three-layer extrusion temperature and co-extrusion blown film setting in S1 of this application result in a more uniform and stable release film. In general processes, the gusseted area cannot be coated with silicone, causing the gusseted area to fail to release. This application solves this problem by first coating both sides with silicone oil in S3 and S4 before folding into the gusseted structure. Furthermore, the application of silicone oil before perforation prevents silicone oil from penetrating into the inner surface of the release film, thus avoiding heat-sealing issues.

[0035] Furthermore, the extrusion temperatures of the raw materials for the surface layer and the bottom layer are as follows: Zone 1 180-195℃, Zone 2 210-220℃, Zone 3 220-230℃, Zone 4 225-235℃, Zone 5 230-240℃, and Zone 6 225-235℃.

[0036] In a preferred embodiment, the extrusion temperatures of the raw materials for the top and bottom layers are: Zone 1 188-192℃, Zone 2 213-217℃, Zone 3 223-227℃, Zone 4 228-232℃, Zone 5 233-237℃, and Zone 6 228-232℃.

[0037] Furthermore, the extrusion temperature of the raw material for preparing the middle layer is: Zone 1 180-195℃, Zone 2 210-220℃, Zone 3 225-235℃, Zone 4 230-240℃, Zone 5 235-245℃, and Zone 6 230-240℃.

[0038] Furthermore, the temperature of the die head area of ​​the extruder is 225-235℃.

[0039] Furthermore, the coating process temperatures for S3 are: Zone 1 65-80℃, Zone 2 95-110℃, Zones 3-6 118-130℃, Zone 7 95-110℃, and Zone 8 65-80℃. Higher curing temperatures in the coating machine result in better silicone oil curing and a better release effect for the release film. However, excessively high curing temperatures can cause localized adhesion of the bottom layers of the release film, preventing the film from opening and rendering the product unusable. This significantly reduces the processability and yield of the product. Therefore, the coating temperature needs to be set according to the specific release film formulation.

[0040] In a preferred embodiment, the coating process temperature of S3 is: 67-73℃ for zone 1, 102-108℃ for zone 2, 122-128℃ for zones 3 to 6, 102-108℃ for zone 7, and 67-73℃ for zone 8.

[0041] Finally, the present invention also provides the application of the breathable release packaging film in molten hot melt adhesive packaging.

[0042] Beneficial effects

[0043] 1. The breathable release packaging film of this application can be automatically spread into a carton by a robotic arm to achieve automated production and improve packaging efficiency. In addition, the breathable release packaging film has a certain antistatic property, which can avoid the problem of multiple layers of packaging film being unable or difficult to separate due to electrostatic adsorption.

[0044] 2. The breathable release packaging film of this application has a pinhole structure of 0.5mm to 1mm. When hot melt adhesive is loaded, the air generated when the hot melt adhesive flows on the carton will be discharged in time, preventing the phenomenon of gas generation causing the breathable release packaging film to burst.

[0045] 3. The breathable release packaging film of this application optimizes the composition, amount and type of each layer structure, which can improve its heat resistance to 125-135℃. When loaded with molten hot melt adhesive (70-90℃), there will be no burns such as deformation and perforation.

[0046] 4. The breathable release packaging film of this application optimizes the coating temperature and other conditions of the preparation process, which can ensure a good curing effect of the silicone oil layer, giving it an excellent release effect. There is no sticky phenomenon when it is peeled off after use. The optimized co-extrusion temperature can ensure that the base film is more uniform, and the product has better heat resistance, processability and product yield.

[0047] 5. This application optimizes the preparation process of the breathable release packaging film, which can avoid the influence of silicone oil layer penetration on the heat sealing effect of the packaging film, and also solves the problem that silicone cannot be applied to the gusset area. Attached Figure Description

[0048] Figure 1 : A schematic diagram of the structure of the breathable release packaging film of this application;

[0049] Wherein, A: silicone oil layer; B: top layer; C: middle layer; D: bottom layer. Detailed Implementation

[0050] Example

[0051] Example 1

[0052] This embodiment provides a breathable release packaging film, which includes, from top to bottom, a silicone oil layer and a base film composed of a top layer, a middle layer and a bottom layer. The thickness of the base film is 0.025 mm, wherein the thickness of the top layer is 30% of the thickness of the base film, the thickness of the middle layer is 40% of the thickness of the base film, and the thickness of the bottom layer is 30% of the thickness of the base film.

[0053] Based on 100% by weight of vinyl silicone oil, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.8% hydrogen-containing silicone oil crosslinking agent, 1.4% chloroplatinic acid catalyst, 0.2% anchoring agent, and 400% 120-octane gasoline. The vinyl silicone oil was purchased from Dow 7558, the hydrogen-containing silicone oil crosslinking agent from Dow 7028, the chloroplatinic acid catalyst from Dow 5000, and the anchoring agent from Dow 9176.

[0054] Based on the total mass of the raw materials used to prepare the surface layer, the raw materials for preparing the surface layer are: 78% high-density polyethylene, 10% linear low-density polyethylene, 10% polyolefin elastomer, and 2% antistatic agent.

[0055] Based on the total mass of the raw materials used to prepare the middle layer, the raw materials used to prepare the middle layer are: 85% high-density polyethylene and 15% linear low-density polyethylene.

[0056] Based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer are: 90% high-density polyethylene, 5% linear low-density polyethylene, and 5% polyolefin elastomer.

[0057] In the top, middle, and bottom layers described above, the high-density polyethylene was purchased from Daqing Petrochemical, HDPE 6097; the linear low-density polyethylene had a melt flow rate of 1 g / 10 min at 190°C and 2.16 kg, and a melt temperature of 119°C, and was purchased from Dow LLDPE 2045G; the polyolefin elastomer had a Mooney viscosity of 54 MU at 121°C and a tensile modulus of 2.9 MPa, and was purchased from Dow POE 7387; the antistatic agent was purchased from Heyan Yuese Plastic Pigment Additives Co., Ltd., PPPE-2P, a permanent antistatic agent for polyamide resin.

[0058] The breathable release film has pinholes with a diameter of 0.8 mm and a dry silica content of 0.4 g / m³. 2 .

[0059] This embodiment also provides a method for preparing the breathable release packaging film, including the following steps:

[0060] S1. The raw materials for the preparation of the top layer, middle layer and bottom layer are mixed separately and then subjected to three-layer co-extrusion blow molding to form a cylindrical film.

[0061] The extrusion temperatures for the surface and bottom layer raw materials are as follows: Zone 1: 190℃, Zone 2: 215℃, Zone 3: 225℃, Zone 4: 230℃, Zone 5: 235℃, Zone 6: 230℃. The extrusion temperatures for the middle layer raw materials are as follows: Zone 1: 190℃, Zone 2: 215℃, Zone 3: 230℃, Zone 4: 235℃, Zone 5: 240℃, Zone 6: 235℃. The die head area temperatures of the extruder are as follows: Zone 1: 235℃, Zone 2: 235℃, Zone 3: 230℃, Zone 4: 230℃, Zone 5: 225℃.

[0062] S2, double-sided corona treatment of the diaphragm.

[0063] S3. Coat both sides of the diaphragm with silicone oil sequentially; wherein, the coating machine speed is 62m / min, the silicone PU roller pressure is 0.25±0.05MPa, the silicone oven tension is 6N, and the coating process temperature is: Zone 1 70℃, Zone 2 105℃, Zones 3 to 6 125℃, Zone 7 105℃, Zone 8 70℃.

[0064] S4. After punching holes in the tubular film, fold it into an accordion structure and cut the bag.

[0065] Example 2

[0066] This embodiment provides a breathable release packaging film, which includes, from top to bottom, a silicone oil layer and a base film composed of a top layer, a middle layer and a bottom layer. The thickness of the base film is 0.05 mm, wherein the thickness of the top layer is 40% of the thickness of the base film, the thickness of the middle layer is 30% of the thickness of the base film, and the thickness of the bottom layer is 30% of the thickness of the base film.

[0067] Based on 100% by weight of vinyl silicone oil, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.7% hydrogen-containing silicone oil crosslinking agent, 1.2% chloroplatinic acid catalyst, 0.5% anchoring agent, and 600% 120-octane gasoline. The vinyl silicone oil was purchased from Dow 7558, the hydrogen-containing silicone oil crosslinking agent from Dow 7028, the chloroplatinic acid catalyst from Dow 5000, and the anchoring agent from Dow 9176.

[0068] Based on the total mass of the raw materials used to prepare the surface layer, the raw materials for preparing the surface layer are: 82% high-density polyethylene, 10% linear low-density polyethylene, 5% polyolefin elastomer, and 3% antistatic agent.

[0069] Based on the total mass of the raw materials used to prepare the middle layer, the raw materials used to prepare the middle layer are: 90% high-density polyethylene and 10% linear low-density polyethylene.

[0070] Based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer are: 86% high-density polyethylene, 7% linear low-density polyethylene, and 7% polyolefin elastomer.

[0071] In the top, middle, and bottom layers described above, the high-density polyethylene was purchased from Daqing Petrochemical, HDPE 6097; the linear low-density polyethylene had a melt flow rate of 1 g / 10 min at 190°C and 2.16 kg, and a melt temperature of 119°C, and was purchased from Dow LLDPE 2045G; the polyolefin elastomer had a Mooney viscosity of 54 MU at 121°C and a tensile modulus of 2.9 MPa, and was purchased from Dow POE 7387; the antistatic agent was purchased from Heyan Yuese Plastic Pigment Additives Co., Ltd., PPPE-2P, a permanent antistatic agent for polyamide resin.

[0072] The breathable release film has pinholes with a diameter of 1.0 mm and a dry silica content of 0.4 g / m³. 2 .

[0073] This embodiment also provides a method for preparing the breathable release packaging film, including the following steps:

[0074] S1. The raw materials for the preparation of the top layer, middle layer and bottom layer are mixed separately and then subjected to three-layer co-extrusion blow molding to form a cylindrical film.

[0075] The extrusion temperatures for the surface and bottom layer raw materials are as follows: Zone 1: 192℃, Zone 2: 217℃, Zone 3: 227℃, Zone 4: 232℃, Zone 5: 237℃, Zone 6: 232℃. The extrusion temperatures for the middle layer raw materials are as follows: Zone 1: 195℃, Zone 2: 220℃, Zone 3: 235℃, Zone 4: 240℃, Zone 5: 245℃, Zone 6: 240℃. The die head area temperatures of the extruder are as follows: Zone 1: 235℃, Zone 2: 235℃, Zone 3: 230℃, Zone 4: 230℃, Zone 5: 225℃.

[0076] S2, double-sided corona treatment of the diaphragm.

[0077] S3. Coat both sides of the diaphragm with silicone oil sequentially; wherein, the coating machine speed is 65m / min, the silicone PU roller pressure is 0.25±0.05MPa, the silicone oven tension is 10N, and the coating process temperature is: Zone 1 73℃, Zone 2 108℃, Zones 3-6 128℃, Zone 7 108℃, Zone 8 73℃.

[0078] S4. After punching holes in the tubular film, fold it into an accordion structure and cut the bag.

[0079] Example 3

[0080] This embodiment provides a breathable release packaging film, which includes, from top to bottom, a silicone oil layer and a base film composed of a top layer, a middle layer and a bottom layer. The thickness of the base film is 0.02 mm, wherein the thickness of the top layer is 20% of the thickness of the base film, the thickness of the middle layer is 40% of the thickness of the base film, and the thickness of the bottom layer is 40% of the thickness of the base film.

[0081] Based on 100% by weight of vinyl silicone oil, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.8% hydrogen-containing silicone oil crosslinking agent, 1.4% chloroplatinic acid catalyst, 1% anchoring agent, and 200% 120-octane gasoline. The vinyl silicone oil was purchased from Dow 7558, the hydrogen-containing silicone oil crosslinking agent from Dow 7028, the chloroplatinic acid catalyst from Dow 5000, and the anchoring agent from Dow 9176.

[0082] Based on the total mass of the raw materials used to prepare the surface layer, the raw materials for preparing the surface layer are: 75% high-density polyethylene, 11% linear low-density polyethylene, 13% polyolefin elastomer, and 1% antistatic agent.

[0083] Based on the total mass of the raw materials used to prepare the middle layer, the raw materials used to prepare the middle layer are: 80% high-density polyethylene and 20% linear low-density polyethylene.

[0084] Based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer are: 92% high-density polyethylene, 5% linear low-density polyethylene, and 3% polyolefin elastomer.

[0085] In the top, middle, and bottom layers described above, the high-density polyethylene was purchased from Daqing Petrochemical, HDPE 6097; the linear low-density polyethylene had a melt flow rate of 1 g / 10 min at 190°C and 2.16 kg, and a melt temperature of 119°C, and was purchased from Dow LLDPE 2045G; the polyolefin elastomer had a Mooney viscosity of 54 MU at 121°C and a tensile modulus of 2.9 MPa, and was purchased from Dow POE 7387; the antistatic agent was purchased from Heyan Yuese Plastic Pigment Additives Co., Ltd., PPPE-2P, a permanent antistatic agent for polyamide resin.

[0086] The breathable release film has pinholes with a diameter of 0.5 mm and a dry silica content of 0.4 g / m³. 2 .

[0087] This embodiment also provides a method for preparing the breathable release packaging film, including the following steps:

[0088] S1. The raw materials for the preparation of the top layer, middle layer and bottom layer are mixed separately and then subjected to three-layer co-extrusion blow molding to form a cylindrical film.

[0089] The extrusion temperatures for the surface and bottom layer raw materials are as follows: Zone 1: 188℃, Zone 2: 213℃, Zone 3: 223℃, Zone 4: 228℃, Zone 5: 233℃, Zone 6: 228℃. The extrusion temperatures for the middle layer raw materials are as follows: Zone 1: 180℃, Zone 2: 210℃, Zone 3: 225℃, Zone 4: 230℃, Zone 5: 235℃, Zone 6: 230℃. The die head area temperatures of the extruder are as follows: Zone 1: 235℃, Zone 2: 235℃, Zone 3: 230℃, Zone 4: 230℃, Zone 5: 225℃.

[0090] S2, double-sided corona treatment of the diaphragm.

[0091] S3. Coat both sides of the diaphragm with silicone oil sequentially; wherein, the coating machine speed is 60m / min, the silicone PU roller pressure is 0.25±0.05MPa, the silicone oven tension is 4N, and the coating process temperature is: Zone 1 67℃, Zone 2 102℃, Zones 3 to 6 122℃, Zone 7 102℃, Zone 8 67℃.

[0092] S4. After punching holes in the tubular film, fold it into an accordion structure and cut the bag.

[0093] Example 4

[0094] The method is basically the same as in Example 1, except that: based on the mass of vinyl silicone oil as 100%, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.8% hydrogen-containing silicone oil crosslinking agent, 0.9% chloroplatinic acid catalyst, 0.2% anchoring agent, and 400% No. 120 gasoline; the dry silicone content of the breathable release packaging film is 0.2 g / m³. 2 .

[0095] Example 5

[0096] The method is basically the same as in Example 1, except that: based on 100% by weight of vinyl silicone oil, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.8% hydrogen-containing silicone oil crosslinking agent, 1.1% chloroplatinic acid catalyst, 0.2% anchoring agent, and 400% 120-octane gasoline; the dry silicone content of the breathable release film is 0.3 g / m³. 2 .

[0097] Example 6

[0098] The method is basically the same as in Example 1, except that: based on the mass of vinyl silicone oil as 100%, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.8% hydrogen-containing silicone oil crosslinking agent, 1.4% chloroplatinic acid catalyst, 0.2% anchoring agent, and 400% No. 120 gasoline; the dry silicone content of the breathable release packaging film is 0.45 g / m³. 2 .

[0099] Example 7

[0100] It is basically the same as Example 1, except that the coating process temperature of S3 is: 70℃ for Zone 1, 105℃ for Zone 2, 110℃ for Zones 3 to 6, 105℃ for Zone 7, and 70℃ for Zone 8.

[0101] Example 8

[0102] It is basically the same as Example 1, except that the coating process temperature of S3 is: 70℃ for Zone 1, 105℃ for Zone 2, 130℃ for Zones 3 to 6, 105℃ for Zone 7, and 70℃ for Zone 8.

[0103] Example 9

[0104] It is basically the same as Example 1, except that the high-density polyethylene in the top layer, middle layer and bottom layer is replaced with low-density polyethylene, and the low-density polyethylene grade is LDPE 2420D.

[0105] Example 10

[0106] It is basically the same as Example 1, except that the high-density polyethylene is purchased from Yangzi Petrochemical and the model is 5000S.

[0107] Example 11

[0108] It is basically the same as Example 1, except that the linear low-density polyethylene was purchased from Saudi Arabia's Sabic, model 218WJ.

[0109] Example 12

[0110] It is basically the same as Example 1, except that the breathable release packaging film is provided with a pinhole structure with a diameter of 0.2 mm.

[0111] Performance testing methods:

[0112] The performance test results of Example 1 are shown in Table 1, and the comparison results of peel force and residual adhesion rate of other examples are shown in Table 2.

[0113] Table 1

[0114] 1 Longitudinal tensile strength (MPa) ≥30 35 GB / T 1040.3-2006 2 Transverse tensile strength (MPa) ≥25 28 GB / T 1040.3-2006 3 Longitudinal elongation at break (%) ≥400 520 GB / T 1040.3-2006 4 Transverse elongation at break (%) ≥500 600 GB / T 1040.3-2006 5 Heat seal strength (N / 15mm) ≥15 18 GB / T 10003-2008 6 Residual adhesion rate (%) ≥75 80 GB / T 25256-2010 7 Peel force (N / 25mm) ≤0.1 0.06 GB / T 25256-2010 8 Antistatic value (Ω) 10^9～10^12 10^10 GJB2605-96 9 Tp (°C) 125～140 135 GB / T 19466.6-2009

[0115] Table 2

[0116]

[0117] In the above products, the bottom layer of the breathable release film prepared in Example 8 exhibited localized adhesion, making the film unable to be opened and rendering the product unusable. The product in Example 9 had a Tp of 115°C, resulting in burns and perforations when hot melt adhesive was loaded. In Example 12, air inside the packaging could not escape smoothly when hot melt adhesive was loaded, causing the packaged product to burst.

Claims

1. A breathable release packaging film, characterized in that, The breathable release packaging film comprises, from top to bottom, a silicone oil layer and a base film consisting of a top layer, a middle layer, and a bottom layer. The thickness of the base film is 0.02-0.05 mm. Based on the total mass of the raw materials used to prepare the top layer, the raw materials include 65-85% high-density polyethylene, 5-22% linear low-density polyethylene, and 3-15% polyolefin elastomer. Based on the total mass of the raw materials used to prepare the middle layer, the raw materials include 70-95% high-density polyethylene and 5-30% linear low-density polyethylene. Based on the total mass of the raw materials used to prepare the bottom layer, the raw materials include 80-95% high-density polyethylene, 1-12% linear low-density polyethylene, and 1-10% polyolefin elastomer. The thickness of the top layer is 20-40% of the base film thickness, the thickness of the middle layer is 30-50% of the base film thickness, and the thickness of the bottom layer is 20-40% of the base film thickness. Based on 100% by weight of vinyl silicone oil, the raw materials for preparing the silicone oil layer include: 100% vinyl silicone oil, 0.6-0.9% hydrogen-containing silicone oil crosslinking agent, 1.0-1.6% catalyst, 0-1% anchoring agent, and 200-600% solvent; The breathable release packaging film has pinhole structures with a diameter of 0.5-1.5 mm.

2. The breathable release packaging film according to claim 1, characterized in that, Based on the total mass of the raw materials used to prepare the surface layer, the raw materials for preparing the surface layer include 75-82% high-density polyethylene, 5-15% linear low-density polyethylene, and 5-13% polyolefin elastomer.

3. The breathable release packaging film according to claim 1, characterized in that, Based on the total mass of the raw materials used to prepare the bottom layer, the raw materials used to prepare the bottom layer include 86-92% high-density polyethylene, 2-8% linear low-density polyethylene, and 3-7% polyolefin elastomer.

4. The breathable release packaging film according to any one of claims 1-3, characterized in that, In the top, middle, and bottom layers, the high-density polyethylene has a melt flow rate of 0.04-0.8 g / 10 min at 190°C and 2.16 kg; the linear low-density polyethylene has a melt flow rate of 1-2 g / 10 min at 190°C and 2.16 kg; and the polyolefin elastomer has a Mooney viscosity of 45-58 MU at 121°C and a tensile modulus of 1-4.5 MPa.

5. A method for preparing a breathable release packaging film according to any one of claims 1-4, characterized in that, Includes the following steps: S1. The raw materials for the preparation of the top layer, middle layer and bottom layer are mixed separately and then subjected to three-layer co-extrusion blow molding to form a cylindrical film; S2. Double-sided corona treatment of the cylindrical membrane; S3. Apply silicone oil to both sides of the diaphragm in sequence; S4. After punching holes in the tubular film, fold it into an accordion structure and cut the bag.

6. The preparation method according to claim 5, characterized in that, The coating process temperature of S3 is as follows: Zone 1 65-80℃, Zone 2 95-110℃, Zones 3-6 118-130℃, Zone 7 95-110℃, Zone 8 65-80℃.

7. The application of a breathable release packaging film according to any one of claims 1-4 in molten hot melt adhesive packaging.

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