Non-silicon-coated release film and preparation method thereof

Abstract

The invention relates to a non-silicon-coated release film and a preparation method thereof. The release film comprises a two-layer structure, wherein the first layer comprises the following components in parts by mass: 8-12 parts of high-pressure low-density polyethylene, 50-65 parts of linear low-density polyethylene and 25-40 parts of low-pressure high-density polyethylene; the preparation method comprises the following steps that raw materials are added into a screw extruder, the raw materials extruded after plasticization of the screw extruder are introduced into a filter screen to filter out impurities, the raw materials pass through a connector and then enter a die head in a layered mode through a distributor, the raw materials enter a T-shaped flat seam die head at the same time to be extruded, and sheets are extruded through the die head; and the sheet is pressed and shaped through a patterned steel roller and a rubber roller, and the release film is obtained through pressing and shaping. The high-pressure low-density polyethylene, the linear low-density polyethylene and the low-pressure high-density polyethylene are mixed to form a double-layer structure, the first layer serves as an embossing protective layer to enhance the wear resistance and the surface attractiveness of the release film, and the second layer serves as a gluing release layer to ensure good release effect and adhesiveness.

Description

Technical Field

[0001] The present invention relates to the technical field of release films, and in particular to a non-silicon-coated release film and a preparation method thereof. Background Art

[0002] Release film, also known as peeling film, isolation film, separation film, etc., is a film with distinguishable surface energy. Release film has no stickiness or only slight stickiness after contact with specific materials under limited conditions. Due to the advantages of isolation, filling, protection, and easy peeling, release film has been widely used in packaging, printing, flexible circuits, insulation products, circuit boards, lamination, electronics, sealing material films, adhesive products, die-cutting and punching processing and other industries.

[0003] Traditional release films are mostly made of silicon-based materials. However, silicon-based release films have problems such as complex preparation processes, high costs, and possible harm to the environment and operators. Silicon-based materials release harmful substances during production and use, causing harm to the environment and human health; the price of silicon-based materials is relatively high, resulting in high production costs for silicon-coated release films; at the same time, the peeling performance of silicon-coated release films will be affected under special environmental conditions such as high temperature and high humidity, which ultimately affects the performance of the product.

[0004] Chinese patent CN115386123B discloses a silicon-coated release film and its preparation method and application, which comprises: a release film; and at least one layer of modified silicone release agent coated on at least one side of the release film; the modified silicone release agent is cured by free radical ultraviolet light; the modified silicone release agent is prepared by mixing SiO2 porous hollow nano-microspheres with fluorine on the surface with polydopamine, reacting the surface with dimethyldiethoxysilane, dimethylvinylsiloxane, trifluoropropylmethylcyclotrisiloxane, a first coupling agent, and a catalyst to obtain a silicone prepolymer, and then mixing and reacting the prepolymer with an acrylic monomer, an initiator, and a second coupling agent. The release film adopts a complex preparation process, including free radical UV curing, surface modification, mixing reaction and other steps, resulting in relatively high production costs. The raw materials used, such as dimethyldiethoxysilane, dimethylvinylsiloxane, and trifluoropropylmethylcyclotrisiloxane, also further increase the cost. At the same time, silicon-based materials will release harmful substances during production and use, causing environmental pollution, and are difficult to recycle.

[0005] Therefore, the present invention aims to develop a novel non-silicon release film and a preparation method thereof to replace the traditional silicon-coated release film and meet the market demand for high-performance, environmentally friendly release films. Summary of the invention

[0006] In order to meet the market demand for high-performance, environmentally friendly release films, the purpose of the present invention is to provide a non-silicon-coated release film and a preparation method thereof, which has a simple preparation process, low production cost, no solvent volatilization during the production process, and is non-toxic and environmentally friendly.

[0007] The specific technical solutions provided by the present invention are as follows:

[0008] A non-silicon-coated release film, the release film comprises a two-layer structure: a first layer and a second layer, the first layer and the second layer are formed by extrusion, and the first layer and the second layer have the same composition;

[0009] The components include, by weight: 8-12 parts of high-pressure low-density polyethylene, 50-65 parts of linear low-density polyethylene and 25-40 parts of low-pressure high-density polyethylene.

[0010] Preferably, the parameters of the high pressure low density polyethylene are: density 0.91-0.92 g / cm 3 , the melt index is 7.0g / 10min at 190℃ / 2.16kg, the melting temperature is 106℃, the tensile strength at break is 14MPa, and the ultimate elongation is 550%;

[0011] The parameters of linear low-density polyethylene are: density 0.92~0.95g / cm 3 , melting point 123℃, melt index 2.11g / 10min at 190℃ / 2.16kg, tensile strength at break 14.7MPa, ultimate elongation 460%;

[0012] The parameters of low-pressure high-density polyethylene are: density 0.96~0.964g / cm 3 , melting point 135°C, melt index 8.0g / 10min at 190°C / 2.16kg, tensile strength yield 27MPa, ultimate elongation 100%.

[0013] Preferably, the total thickness of the release film is 0.38-0.42 mm, the ratio of the thickness of the first layer to the thickness of the second layer of the release film is 1:1, and the gram weight of the release film is 105-115 g / m 2 .

[0014] Preferably, the first layer of the release film is an embossed protective layer, and the second layer of the release film is a glue-coated release layer.

[0015] The present invention also provides a method for preparing a non-silicon-coated release film, comprising the following steps:

[0016] S1. Mix 8-12 parts of high-pressure low-density polyethylene, 50-65 parts of linear low-density polyethylene and 25-40 parts of low-pressure high-density polyethylene evenly, and use them as the raw material for the first layer; prepare the same materials as the raw materials for the first layer and mix them evenly, and use them as the raw materials for the second layer;

[0017] S2, adding the first layer of raw materials to the first screw extruder, adding the second layer of raw materials to the second screw extruder, passing the first layer of raw materials and the second layer of raw materials extruded by the screw extruder after plasticization through a filter to filter out impurities, and then passing through a connector and entering the die head in layers through a distributor, and the first layer of raw materials and the second layer of raw materials are then simultaneously extruded into a T-shaped flat-slit die head, and the first layer of sheet material and the second layer of sheet material are extruded from the die head respectively;

[0018] S3. Lay the first layer of sheet material on the second layer of sheet material, then make the upper surface of the first layer of sheet material contact with the patterned steel roller, and the lower surface of the second layer of sheet material contact with the rubber roller. Meanwhile, the patterned steel roller and the rubber roller are cooled by constant temperature water, and the first layer of sheet material and the second layer of sheet material are pressed and shaped by the patterned steel roller and the rubber roller. The first layer of sheet material becomes an embossed protective layer, and the second layer of sheet material becomes a glue-coated release layer. The two layers are pressed and shaped into a release film.

[0019] Preferably, the extrusion amounts of the first screw extruder and the second screw extruder are the same, the first screw extruder is provided with 4 heating zones, and the temperatures are set to 170°C, 190°C, 210°C and 230°C in the order in which the first layer of raw materials passes; the second screw extruder is provided with 5 heating zones, and the temperatures are set to 160°C, 180°C, 200°C, 220°C and 230°C in the order in which the second layer of raw materials passes.

[0020] Preferably, the heating temperature of the filter screen is 220-230°C; the heating temperature of the connector is 220-230°C; the heating temperature of the distributor is 220-230°C; the die head is provided with 11 heating zones, and the temperature of the heating zones is all set to 230°C.

[0021] Preferably, the rubber roller pressure is set to 5.5 MPa.

[0022] Preferably, the temperature at which the patterned steel roller and the rubber roller are cooled by constant temperature water is 20°C.

[0023] Preferably, the method further includes step S4, wherein the pressed and shaped release film is air-cooled at room temperature and then enters a traction and flattening system for thickness measurement, winding, and finished product packaging.

[0024] The non-silicon-coated release film and the preparation method thereof of the present invention have the following beneficial effects:

[0025] 1. The present invention mixes high-pressure low-density polyethylene, linear low-density polyethylene and low-pressure high-density polyethylene in a certain proportion, and forms a double-layer structure through processing. The first layer is used as an embossed protective layer to enhance the wear resistance and surface aesthetics of the release film, and the second layer is used as a glue-coated release layer to ensure good release effect and adhesion. Through performance testing, the release film has excellent performance and meets diversified application requirements.

[0026] 2. The non-silicone release film of the present invention does not contain siloxane components, thus avoiding the problem of silicone oil residue pollution and meeting environmental protection requirements.

[0027] 3. The non-silicone release films of the present invention have excellent corrosion resistance, electrical insulation and radiation resistance, and are suitable for a variety of harsh process environments. In addition, they also have good dimensional stability and flexibility, and can maintain stable performance at high temperatures.

[0028] 4. The production process of the non-silicone release film of the present invention is relatively simple, and the cost of raw materials is low, which helps to reduce production costs. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the preferred embodiments.

[0030] Release films are non-sticky or only slightly sticky after contacting with specific materials under limited conditions. Traditional release films are mostly made of silicon-based materials. However, silicon-based release films have complex preparation processes and high costs. They may also cause harm to the environment and operators. In response to the above problems, the inventors tried to prepare release films with similar performance using non-silicon-coated methods. First, in terms of the selection of raw materials, the inventors used low-cost raw materials to prepare release films. The selected raw materials include polypropylene, amino resin, polyethylene and other raw materials. After many experiments, the inventors finally found that a combination of various types of polyethylene can be used to prepare a non-silicon release film with similar performance to the silicon-coated release film. Subsequently, by continuously adjusting the type and proportion of polyethylene, it is ensured that the release film has excellent release effect and adhesiveness. The following is a description through specific embodiments.

[0031] The polyethylene used in the following examples all meets the following conditions:

[0032] High-pressure low-density polyethylene (LDPE) has good fluidity and is easy to process, such as 1C7A, 1C7AS, and 17.0. Its parameters are: density 0.91-0.92 g / cm 3 , the melt index is 7.0g / 10min at 190℃ / 2.16kg, the melting temperature is 106℃, the tensile strength at break is 14MPa, and the ultimate elongation is 550%;

[0033] Linear low-density polyethylene (LLDPE) has poor fluidity and relatively large physical indicators, such as 7042, 222WT, 3305, 0218D, and its parameters are: density 0.92-0.95 g / cm 3 , melting point 123℃, melt index 2.11g / 10min at 190℃ / 2.16kg, tensile strength at break 14.7MPa, ultimate elongation 460%;

[0034] Low-pressure high-density polyethylene (HDPE) has poor fluidity and good mechanical properties, such as 5070, 5000S, 8008, and T60-800. Its parameters are: density 0.96 to 0.964 g / cm 3 , melting point 135°C, melt index 8.0g / 10min at 190°C / 2.16kg, tensile strength yield 27MPa, ultimate elongation 100%.

[0035] Example 1

[0036] This embodiment provides a method for preparing a non-silicon-coated release film, comprising the following steps:

[0037] S1. Mix 2kg of high-pressure low-density polyethylene, 13kg of linear low-density polyethylene and 5kg of low-pressure high-density polyethylene evenly and use them as the raw materials for the first layer; prepare the same materials as the raw materials for the first layer and mix them evenly and use them as the raw materials for the second layer.

[0038] S2, adding the first layer of raw materials to the first screw extruder, adding the second layer of raw materials to the second screw extruder, setting the extrusion amount of the first screw extruder and the second screw extruder to be the same, setting the temperature of the 4 heating zones of the first screw extruder, in the order in which the first layer of raw materials pass, the temperature is set to 170°C, 190°C, 210°C and 230°C; setting the temperature of the 5 heating zones of the second screw extruder, in the order in which the second layer of raw materials pass, the temperature is set to 160°C, 180°C, 200°C, 220°C and 230°C;

[0039] Set the filter screen heating temperature to 230°C, the connector heating temperature to 230°C, and the distributor heating temperature to 230°C; pass the first layer of raw material and the second layer of raw material extruded by the screw extruder after plasticization through the filter screen to filter out impurities, and then pass through the connector and enter the die head in layers through the distributor;

[0040] The die head is provided with 11 heating zones, and the temperature of the heating zones is all set to 230°C. The first layer raw material and the second layer raw material enter the T-shaped flat-slit die head for extrusion at the same time, and the first layer sheet and the second layer sheet are extruded respectively by the die head.

[0041] S3, laminating the first layer of sheet material and the second layer of sheet material, and then making the upper surface of the first layer of sheet material contact with the patterned steel roller, and the lower surface of the second layer of sheet material contact with the rubber roller, and the pressure of the rubber roller is set to 5.5 MPa;

[0042] The patterned steel roller and the rubber roller are cooled by constant temperature water at a cooling temperature of 20°C. The first layer of sheet and the second layer of sheet are cooled, pressed and shaped by the patterned steel roller and the rubber roller. The first layer of sheet becomes the embossed protective layer, and the second layer of sheet becomes the glue-coated release layer. The two layers are pressed and shaped into a release film.

[0043] S4, the pressed and shaped release film is cooled by air at room temperature and then enters the traction and flattening system for thickness measurement, winding, and finished product packaging. The thickness of the release film is measured to be 0.4mm and the weight is 110g / m 2 .

[0044] Example 2

[0045] This embodiment provides a method for preparing a non-silicon-coated release film, comprising the following steps:

[0046] S1. Mix 2.4 kg of high-pressure low-density polyethylene, 10 kg of linear low-density polyethylene and 8 kg of low-pressure high-density polyethylene evenly and use them as the raw material for the first layer; prepare the same materials as the raw materials for the first layer and mix them evenly and use them as the raw materials for the second layer.

[0047] S2, adding the first layer of raw materials to the first screw extruder, adding the second layer of raw materials to the second screw extruder, setting the extrusion amount of the first screw extruder and the second screw extruder to be the same, setting the temperature of the 4 heating zones of the first screw extruder, in the order in which the first layer of raw materials pass, the temperature is set to 170°C, 190°C, 210°C and 230°C; setting the temperature of the 5 heating zones of the second screw extruder, in the order in which the second layer of raw materials pass, the temperature is set to 160°C, 180°C, 200°C, 220°C and 230°C;

[0048] Set the filter screen heating temperature to 230°C, the connector heating temperature to 230°C, and the distributor heating temperature to 230°C; pass the first layer of raw material and the second layer of raw material extruded by the screw extruder after plasticization through the filter screen to filter out impurities, and then pass through the connector and enter the die head in layers through the distributor;

[0049] The die head is provided with 11 heating zones, and the temperature of the heating zones is all set to 230°C. The first layer raw material and the second layer raw material enter the T-shaped flat-slit die head for extrusion at the same time, and the first layer sheet and the second layer sheet are extruded respectively by the die head.

[0050] S3, laminating the first layer of sheet material and the second layer of sheet material, and then making the upper surface of the first layer of sheet material contact with the patterned steel roller, and the lower surface of the second layer of sheet material contact with the rubber roller, and the pressure of the rubber roller is set to 5.5 MPa;

[0051] The patterned steel roller and the rubber roller are cooled by constant temperature water at a cooling temperature of 20°C. The first layer of sheet and the second layer of sheet are cooled, pressed and shaped by the patterned steel roller and the rubber roller. The first layer of sheet becomes the embossed protective layer, and the second layer of sheet becomes the glue-coated release layer. The two layers are pressed and shaped into a release film.

[0052] S4, the pressed and shaped release film is cooled by air at room temperature and then enters the traction and flattening system for thickness measurement, winding, and finished product packaging. The thickness of the release film is measured to be 0.42mm and the weight is 115g / m 2 .

[0053] Example 3

[0054] This embodiment provides a method for preparing a non-silicon-coated release film, comprising the following steps:

[0055] S1. Evenly mix 1.6 kg of high-pressure low-density polyethylene, 11 kg of linear low-density polyethylene and 7 kg of low-pressure high-density polyethylene, and use them as the raw material for the first layer; prepare the same materials as the raw materials for the first layer and mix them evenly, and use them as the raw materials for the second layer.

[0056] S2, adding the first layer of raw materials to the first screw extruder, adding the second layer of raw materials to the second screw extruder, setting the extrusion amount of the first screw extruder and the second screw extruder to be the same, setting the temperature of the 4 heating zones of the first screw extruder, in the order in which the first layer of raw materials pass, the temperature is set to 170°C, 190°C, 210°C and 230°C; setting the temperature of the 5 heating zones of the second screw extruder, in the order in which the second layer of raw materials pass, the temperature is set to 160°C, 180°C, 200°C, 220°C and 230°C;

[0057] Set the filter screen heating temperature to 230°C, the connector heating temperature to 230°C, and the distributor heating temperature to 230°C; pass the first layer of raw material and the second layer of raw material extruded by the screw extruder after plasticization through the filter screen to filter out impurities, and then pass through the connector and enter the die head in layers through the distributor;

[0058] The die head is provided with 11 heating zones, and the temperature of the heating zones is all set to 230°C. The first layer raw material and the second layer raw material enter the T-shaped flat-slit die head for extrusion at the same time, and the first layer sheet and the second layer sheet are extruded respectively by the die head.

[0059] S3, laminating the first layer of sheet material and the second layer of sheet material, and then making the upper surface of the first layer of sheet material contact with the patterned steel roller, and the lower surface of the second layer of sheet material contact with the rubber roller, and the pressure of the rubber roller is set to 5.5 MPa;

[0060] The patterned steel roller and the rubber roller are cooled by constant temperature water at a cooling temperature of 20°C. The first layer of sheet and the second layer of sheet are cooled, pressed and shaped by the patterned steel roller and the rubber roller. The first layer of sheet becomes the embossed protective layer, and the second layer of sheet becomes the glue-coated release layer. The two layers are pressed and shaped into a release film.

[0061] S4, the pressed and shaped release film is cooled by air at room temperature and then enters the traction and flattening system for thickness measurement, winding, and finished product packaging. The thickness of the release film is measured to be 0.38mm and the weight is 105g / m 2 .

[0062] Comparative Example 1

[0063] Compared with Example 1, no high-pressure low-density polyethylene is added to the raw material components, and the first layer raw material and the second layer raw material components are adjusted to 13 kg of linear low-density polyethylene and 7 kg of low-pressure high-density polyethylene, and other steps remain unchanged to prepare a release film.

[0064] Comparative Example 2

[0065] Compared with Example 1, no high-pressure low-density polyethylene is added to the raw material components, and the first layer raw material and the second layer raw material components are adjusted to 25 kg of linear low-density polyethylene and 5 kg of low-pressure high-density polyethylene, and other steps remain unchanged to prepare a release film.

[0066] Comparative Example 3

[0067] Compared with Example 1, low-pressure high-density polyethylene was not added to the raw material components, and the other components and steps remained unchanged to prepare a release film.

[0068] The release films prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests:

[0069] The test standard is implemented in accordance with GB / T25256-2010, and the 180° peeling force of the release film is tested. The pressure-sensitive tape model is TESA7475, and the test is placed for 20 minutes. The test roller surface is tested, the clamping distance is 150mm, the test speed is 300mm / min, the peeling length is 100mm, and the unit conversion is 1mm=0.001N. The specific test results are shown in Table 1.

[0070] Table 1 180° peeling force and residual adhesion rate of release film

[0071]

[0072] From the above test results, it can be seen that the present invention adopts high-pressure low-density polyethylene, linear low-density polyethylene and low-pressure high-density polyethylene mixed in a certain proportion, and through processing, a double-layer structure is formed. The first layer is used as an embossed protective layer to enhance the wear resistance and surface aesthetics of the release film, and the second layer is used as a glue-coated release layer to ensure good release effect and adhesion. Through performance testing, the release film has excellent performance and meets the needs of diversified applications.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A non-silicon-coated release film, characterized in that: The release film comprises a two-layer structure: a first layer and a second layer, the first layer and the second layer are formed by extrusion, and the first layer and the second layer have the same composition; The components include, by weight: 8-12 parts of high-pressure low-density polyethylene, 50-65 parts of linear low-density polyethylene and 25-40 parts of low-pressure high-density polyethylene.

2. The non-silicon-coated release film according to claim 1, characterized in that: The parameters of high pressure low density polyethylene are: density 0.91~0.92g / cm 3 , the melt index is 7.0g / 10min at 190℃ / 2.16kg, the melting temperature is 106℃, the tensile strength at break is 14MPa, and the ultimate elongation is 550%; The parameters of linear low-density polyethylene are: density 0.92~0.95g / cm 3 , melting point 123℃, melt index 2.11g / 10min at 190℃ / 2.16kg, tensile strength at break 14.7MPa, ultimate elongation 460%; The parameters of low-pressure high-density polyethylene are: density 0.96~0.964g / cm 3 , melting point 135°C, melt index 8.0g / 10min at 190°C / 2.16kg, tensile strength yield 27MPa, ultimate elongation 100%.

3. The non-silicon-coated release film according to claim 1, characterized in that: The total thickness of the release film is 0.38-0.42 mm, the ratio of the thickness of the first layer to the thickness of the second layer of the release film is 1:1, and the gram weight of the release film is 105-115 g / m 2 .

4. The non-silicon-coated release film according to claim 1, characterized in that: The first layer of the release film is an embossed protective layer, and the second layer of the release film is a glue-coated release layer.

5. A method for preparing a non-silicon-coated release film according to claims 1-4, characterized in that: The following steps are involved: S1. Mix 8-12 parts of high-pressure low-density polyethylene, 50-65 parts of linear low-density polyethylene and 25-40 parts of low-pressure high-density polyethylene evenly, and use them as the raw material for the first layer; prepare the same materials as the raw materials for the first layer and mix them evenly, and use them as the raw materials for the second layer; S2, adding the first layer of raw materials to the first screw extruder, adding the second layer of raw materials to the second screw extruder, passing the first layer of raw materials and the second layer of raw materials extruded by the screw extruder after plasticization through a filter to filter out impurities, and then passing through a connector and entering the die head in layers through a distributor, and the first layer of raw materials and the second layer of raw materials are then simultaneously extruded into a T-shaped flat-slit die head, and the first layer of sheet material and the second layer of sheet material are extruded from the die head respectively; S3. Lay the first layer of sheet material on the second layer of sheet material, then make the upper surface of the first layer of sheet material contact with the patterned steel roller, and the lower surface of the second layer of sheet material contact with the rubber roller. Meanwhile, the patterned steel roller and the rubber roller are cooled by constant temperature water, and the first layer of sheet material and the second layer of sheet material are pressed and shaped by the patterned steel roller and the rubber roller. The first layer of sheet material becomes an embossed protective layer, and the second layer of sheet material becomes a glue-coated release layer. The two layers are pressed and shaped into a release film.

6. The method for preparing a non-silicon-coated release film according to claim 5, characterized in that: The extrusion capacity of the first screw extruder and the second screw extruder is the same. The first screw extruder is provided with 4 heating zones. The temperatures are set to 170°C, 190°C, 210°C and 230°C in the order that the first layer of raw materials passes through; the second screw extruder is provided with 5 heating zones. The temperatures are set to 160°C, 180°C, 200°C, 220°C and 230°C in the order that the second layer of raw materials passes through.

7. The method for preparing a non-silicon-coated release film according to claim 5, characterized in that: The heating temperature of the filter screen is 220-230°C; the heating temperature of the connector is 220-230°C; the heating temperature of the distributor is 220-230°C; the die head is provided with 11 heating zones, and the temperature of the heating zones is all set to 230°C.

8. The method for preparing a non-silicon-coated release film according to claim 5, characterized in that: The rubber roller pressure was set to 5.5 MPa.

9. The method for preparing a non-silicon-coated release film according to claim 5, characterized in that: The temperature of the patterned steel roller and the rubber roller is 20℃ through constant temperature water cooling.

10. The method for preparing a non-silicon-coated release film according to claim 5, characterized in that: The method also includes step S4, wherein the pressed and formed release film is cooled by air at room temperature and then enters a traction and flattening system for thickness measurement, winding, and finished product packaging.

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