High-strength high-toughness ultra-thin dry film protective film and preparation method thereof

Abstract

The application discloses a kind of high-strength high-toughness ultra-thin dry film protective film and preparation method thereof, it is related to dry film protective film field, the protective film is made of laminating layer, core layer, back layer composite, core layer is located laminating layer and back layer between, made of following components: low-density polyethylene 40~70 parts, crosslinked polyethylene 10~20 parts, cyclic polyolefin 20~40 parts, modified montmorillonite 3~10 parts;The protective film has excellent water-oxygen barrier property, effectively prevent dry film layer from being eroded by oxygen and moisture, ensure the solidification rate and quality of photosensitive dry film;Unique three-layer structure and material combination endow the protective film with excellent mechanical properties, including high tensile strength and elongation at break, ensure that it will not be broken or deformed during peeling process;In addition, the protective film of the application also has good processing performance and high yield, effectively solve the problem that ultra-thin film is difficult to process, defect control is difficult, etc., improve production efficiency and product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of dry film protective films, in particular to a high-strength and high-toughness ultra-thin dry film protective film and a preparation method thereof. BACKGROUND

[0002] Dry film protective film is a key component in the manufacturing process of photosensitive dry film, and is usually composed of three layers: polyolefin dry film protective film, intermediate photosensitive dry film layer, and PET carrier protective layer. Among them, the polyolefin dry film protective film plays a crucial role in protecting the photosensitive dry film layer from oxygen and moisture erosion.

[0003] The photosensitive dry film layer is a gel-like high molecular compound sensitive to ultraviolet light, mainly used for precise etching of circuit boards. Under ultraviolet irradiation, the dry film layer undergoes polymerization reaction to form a stable substance that does not react with etching solution. However, the chemical composition of the dry film is extremely sensitive to oxygen and moisture, and excessive water vapor and oxygen can cause the photosensitive glue to degrade, reducing the exposure rate and severely affecting the curing rate of the dry film. Therefore, the industry has very strict control over the water and oxygen transmission rate of polyolefin dry film protective film.

[0004] Chinese patent document CN107696652A discloses a protective film for photosensitive dry film, which is prepared by multi-layer co-extrusion casting or multi-layer co-extrusion stretching. The protective film includes an intermediate PP layer and two surface layers, one of which is a PE release layer, and the other is an anti-slip layer; the intermediate PP layer is completely made of PP material; the PE release layer is completely made of PE material, and the surface of the release layer does not add release agent; the anti-slip layer is completely made of PE material, or made of a copolymer or blend of PP material and PE material.

[0005] Currently, dry film protective films on the market are mainly produced by blowing film method and casting method, with a thickness usually between 17-28μm, of which 19μm is the most common. However, in the interest of energy saving and environmental protection and cost reduction, the industry is seeking ways to further thin the dry film protective film. Reducing the thickness to below 17μm can significantly reduce the product weight per square meter and the use cost.

[0006] However, directly reducing the thickness brings a series of technical challenges:

[0007] 1. Increased water and oxygen transmission rate: This will adversely affect the curing rate of the dry film.

[0008] 2. Mechanical property degradation: leading to deformation and film breakage when peeling off the protective film, affecting production efficiency. At the same time, the protective film with reduced mechanical properties is prone to shrinkage and deformation after being attached to the photosensitive dry film glue, affecting the thickness of the photosensitive glue layer, and thus affecting the quality and use of the dry film.

[0009] 3. Processing difficulty increases: higher requirements for defect control of crystal points, foreign matter, oil stains, etc. Especially under the condition of blow molding process, it is more likely to cause membrane rupture due to uneven thickness.

[0010] 4. Yield and output efficiency decrease: due to the requirement of long continuous winding meters for finished product roll, the generation of the above defects reduces the yield and overall output efficiency of dry film protective film.

[0011] In addition, the dry film protective film also needs to have sufficient adhesion to tightly adhere to the surface of the dry film and reduce the contact between the dry film and the air. At the same time, it needs to have high tensile strength and elongation at break to ensure that it will not be broken and affect the use efficiency.

[0012] Therefore, it is of great practical significance and market value to develop a high-strength and high-toughness ultra-thin dry film protective film that can meet the requirements of ultra-thin thickness (thickness less than 17 μm) and maintain excellent water and oxygen barrier properties, good mechanical properties and processing performance, as well as a corresponding preparation method. SUMMARY

[0013] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a high-strength and high-toughness ultra-thin dry film protective film and a preparation method thereof. The protective film has excellent water and oxygen barrier properties, effectively prevents the dry film layer from being eroded by oxygen and moisture, and ensures the curing rate and quality of the photosensitive dry film. The unique three-layer structure and material combination endow the protective film with excellent mechanical properties, including high tensile strength and elongation at break, ensuring that it will not be broken or deformed during the peeling process. In addition, the protective film of the present application also has good processing performance and high yield, effectively solving the problems of difficult processing of ultra-thin film and difficult defect control, improving the production efficiency and product quality.

[0014] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0015] A high-strength and high-toughness ultra-thin dry film protective film is composed of a bonding layer, a core layer and a back layer. The core layer is located between the bonding layer and the back layer. The core layer is made of the following components in parts by weight: low density polyethylene 40-70 parts, cross-linked polyethylene 10-20 parts, cyclic polyolefin 20-40 parts, and modified montmorillonite 3-10 parts.

[0016] Preferably, the bonding layer is made of the following components in parts by weight: low density polyethylene 10-30 parts, metallocene polyethylene 50-80 parts, cyclic polyolefin 10-20 parts, and diatomite 0.1-0.5 parts.

[0017] Preferably, the back layer is made of the following components in parts by weight: low density polyethylene 10-30 parts, metallocene polyethylene 50-80 parts, cyclic polyolefin 10-20 parts, and diatomite 0.1-0.5 parts.

[0018] Preferably, the low-density polyethylene has a molecular weight of 100-300 thousand; the cyclic polyolefin has a molecular weight of 8000-30000 and a glass transition temperature of 50-160℃.

[0019] Preferably, the cross-linked polyethylene is prepared by cross-linking low-density polyethylene powder having a particle size of 0.5-1 μm and a melt index of 2-4 g / min using electron beam irradiation technology to obtain cross-linked polyethylene powder having a particle size of 0.5-1 μm.

[0020] Preferably, the total thickness of the dry film protective film is < 17 μm; the thickness of the adhesion layer is 5-50% of the total thickness; and the thickness of the backing layer is 5-50% of the total thickness.

[0021] Specifically, the thickness of the adhesion layer can be 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% of the total thickness.

[0022] Specifically, the thickness of the adhesion layer can be 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50% of the total thickness.

[0023] Preferably, the method for preparing the modified montmorillonite comprises the following steps:

[0024] (1) calcining montmorillonite and then cooling to room temperature to obtain activated montmorillonite;

[0025] The activated montmorillonite is obtained by calcining montmorillonite and then cooling to room temperature. During the calcination process, the high temperature causes the structural water in the montmorillonite to separate, increasing its specific surface area and porosity. This process destroys part of the crystal structure of the montmorillonite, exposing more active sites and thus increasing its reactivity.

[0026] Preferably, in step (1), the calcination conditions are calcination at 500-600℃ for 2-3 h in an air atmosphere.

[0027] Specifically, in step (1), the calcination temperature can be 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, or 600℃, and the reaction time can be 2, 2.5, or 3 h.

[0028] (2) adding activated montmorillonite and hexadecyl succinic anhydride to toluene and stirring under nitrogen protection to react, centrifuging the product, washing with alcohol, and drying to obtain anhydride-modified montmorillonite;

[0029] Anhydride modification: the activated montmorillonite is reacted with hexadecyl succinic anhydride in toluene. The anhydride groups in the hexadecyl succinic anhydride react with the hydroxyl groups on the surface of the montmorillonite to form ester bonds and introduce carboxyl groups and long chain alkyl groups on the surface of the montmorillonite. This process increases the hydrophobicity of the montmorillonite and introduces new reaction sites (carboxyl groups) on the surface. A nitrogen atmosphere is used to protect the reaction environment from moisture and oxygen and to improve the reaction efficiency.

[0030] Preferably, in step (2), the amount of the activated montmorillonite and the hexadecyl succinic anhydride is 10 g: 6.5-12.9 g.

[0031] Preferably, in step (2), the stirring reaction is performed at 70-80°C for 6-8 h with simultaneous ultrasonic treatment.

[0032] Specifically, in step (2), the stirring reaction temperature can be 70, 71, 72, 73, 74, 75, 76, 77, 78, 79 or 80°C, and the stirring reaction time can be 6, 7 or 8 h.

[0033] (3) The anhydride-modified montmorillonite and perfluorodecanol are added to tetrahydrofuran, and 4-dimethylaminopyridine is added, and the reaction is performed under reflux in a nitrogen atmosphere. The product is centrifuged, washed with alcohol and dried to obtain the modified montmorillonite.

[0034] Fluorination modification: the anhydride-modified montmorillonite is reacted with perfluorodecanol in tetrahydrofuran, and 4-dimethylaminopyridine is used as a catalyst. In this stage, the hydroxyl groups of the perfluorodecanol esterify with the carboxyl groups introduced in the second stage under the action of the catalyst. This process introduces perfluoroalkyl chains on the surface of the montmorillonite to further enhance its hydrophobicity. A nitrogen atmosphere is also used to protect the reaction environment and prevent side reactions.

[0035] Preferably, in step (3), the amount of the anhydride-modified montmorillonite and the perfluorodecanol is 10 g: 9.3-13.9 g, and the amount of 4-dimethylaminopyridine is 5-10 wt% of the perfluorodecanol.

[0036] Preferably, in step (3), the reflux reaction is performed at 60-65°C for 6-9 h with simultaneous vigorous stirring.

[0037] Specifically, in step (3), the reflux reaction temperature can be 60, 61, 62, 63, 64 or 65°C, and the reflux reaction time can be 6, 7, 8 or 9 h.

[0038] The application also claims a method for preparing the high-strength and high-toughness ultra-thin dry film protective film, comprising the following steps: mixing raw materials according to the formula, melting through three single-screw extruders respectively, film forming through a material block connector, a die head co-extrusion and cooling, and obtaining the high-strength and high-toughness ultra-thin dry film protective film through subsequent cooling and shaping, thickness detection, online slitting, winding and packaging.

[0039] Compared with the prior art, the application has the following beneficial effects:

[0040] 1. The application provides a high-strength and high-toughness ultra-thin dry film protective film, which successfully reduces the thickness to below 17 microns while maintaining excellent comprehensive performance. The core layer uses a combination of low-density polyethylene, cross-linked polyethylene, cyclic polyolefin and modified montmorillonite, achieving a balance between strength and toughness. Among them, the low-density polyethylene provides good flexibility and processing performance, the cross-linked polyethylene enhances the strength and thermal stability of the material, the cyclic polyolefin improves the barrier performance and transparency, and the modified montmorillonite significantly improves the water and oxygen barrier performance. The adhesive layer and the back layer use a combination of low-density polyethylene, metallocene polyethylene, cyclic polyolefin and diatomite, wherein the metallocene polyethylene provides excellent adhesion and peel strength, the cyclic polyolefin enhances the heat resistance and dimensional stability, and the diatomite improves the smoothness. The synergistic effect of this multi-layer structure and material formula gives the protective film excellent water and oxygen barrier performance, effectively preventing the dry film layer from being eroded by oxygen and moisture, ensuring the curing rate and quality of the photosensitive dry film. At the same time, it provides excellent mechanical properties, including high tensile strength and elongation at break, ensuring that it will not break or deform during peeling. In addition, the protective film of the application also has good processing performance and high yield, effectively solving the problems of difficult processing of ultra-thin films and difficult defect control, improving production efficiency and product quality.

[0041] 2. The application provides a method for preparing modified montmorillonite. First, high-temperature calcination activates the montmorillonite, effectively increasing the interlayer distance of the montmorillonite, increasing the specific surface area and the number of surface active functional groups, laying a foundation for subsequent modification. The subsequent acid anhydride reaction grafts long-chain alkyl groups on the surface of the montmorillonite, significantly improving the compatibility of the montmorillonite with the organic matrix. The final esterification reaction introduces fluorine-containing groups, further enhancing the hydrophobicity of the montmorillonite. This multi-step modification process makes the montmorillonite obtain a unique interlayer structure and surface properties, changing from hydrophilic to highly hydrophobic while retaining the original layered structure characteristics.

[0042] 3、The modified montmorillonite prolongs the gas diffusion path of the lamellar structure of the montmorillonite, effectively blocks the penetration of moisture and oxygen, then grafts hexadecyl succinic anhydride, introduces long-chain alkyl into the surface of the montmorillonite, improves the compatibility between the montmorillonite and the resin matrix, the long-chain alkane can also interfere with the diffusion of water vapor, finally grafts perfluorodecanol, continuously enhances the hydrophobicity, delays the speed of water molecules entering the matrix, and synergistically enhances the barrier property of the film. Secondly, the modified montmorillonite also improves the bonding force with the resin, enhances the mechanical strength of the polymer matrix, improves the ductility, tensile strength and tear resistance of the protective film, and also significantly improves the thermal stability and chemical resistance of the material, prolongs the service life of the protective film. The protective film of the present application realizes the comprehensive improvement of the mechanical properties and barrier properties while maintaining the ultra-thin characteristics, and meets the various requirements of high-performance dry film protective film. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with embodiments. Of course, the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0044] Unless otherwise specified, the chemical reagents and materials in the present application are purchased through market channels or synthesized from raw materials purchased through market channels.

[0045] The metallocene polyethylene includes but is not limited to the EXCEED series of Exxon Mobil Chemical, such as 1018, 2018, 3518 and 6026, etc.; the SP1540, SP2040 and SP0540 series of Mitsui Chemical, etc.

[0046] The diatomite is purchased from Hebei Jetgui Mineral Products Co., Ltd., and the mesh number is 325-500 mesh.

[0047] A preparation method of a high-strength and high-toughness ultra-thin dry film protective film, comprising the following steps:

[0048] (1) calcining the montmorillonite at 500-600 DEG C. for 2-3 h in an air atmosphere, and then cooling to room temperature to obtain activated montmorillonite;

[0049] (2) adding 10 g of the activated montmorillonite and 6.5-12.9 g of hexadecyl succinic anhydride into 100 mL of toluene, stirring and reacting at 70-80 DEG C. under a nitrogen atmosphere for 6-8 h, while ultrasonic treatment is carried out, centrifuging, alcohol washing and drying the product to obtain anhydride-modified montmorillonite;

[0050] (3) 10 g acid anhydride montmorillonite, 9.3-13.9 g perfluorodecanol is added to 100 mL tetrahydrofuran, then 0.465-1.39 g 4-dimethylaminopyridine is added, and the reaction is carried out under reflux at 60-65 °C under nitrogen atmosphere for 6-9 h while strong stirring is carried out, the product is centrifuged, alcohol washed and dried to obtain modified montmorillonite;

[0051] (4) The raw materials are respectively mixed according to the formula, then respectively melt through three single screw extruders, and then film forming is carried out through a material block connector, a die co-extrusion and cooling, and then the product is cooled, shaped, thickness detected, cut, rolled and packaged to obtain the high-strength high-toughness ultra-thin dry film protective film.

[0052] The core layer is made of the following components in parts by weight: low density polyethylene 40-70 parts, crosslinked polyethylene 10-20 parts, cyclic polyolefin 20-40 parts, modified montmorillonite 3-10 parts; the adhesion layer is made of the following components in parts by weight: low density polyethylene 10-30 parts, metallocene polyethylene 50-80 parts, cyclic polyolefin 10-20 parts, diatomite 0.1-0.5 parts; the back layer is made of the following components in parts by weight: low density polyethylene 10-30 parts, metallocene polyethylene 50-80 parts, cyclic polyolefin 10-20 parts, diatomite 0.1-0.5 parts.

[0053] The total thickness of the dry film protective film is < 17 μm; the thickness of the adhesion layer is 5-50% of the total thickness; the thickness of the back layer is 5-50% of the total thickness.

[0054] The application will be further described below through specific examples.

[0055] Example 1

[0056] A preparation method of a high-strength high-toughness ultra-thin dry film protective film, comprising the following steps:

[0057] (1) Montmorillonite is calcined at 600 °C under air atmosphere for 2 h, and then cooled to room temperature to obtain activated montmorillonite;

[0058] (2) 10 g activated montmorillonite, 12.9 g hexadecyl succinic anhydride is added to 100 mL toluene, and the reaction is carried out under stirring at 80 °C under nitrogen atmosphere for 6 h while ultrasonic treatment is carried out, the product is centrifuged, alcohol washed and dried to obtain acid anhydride montmorillonite;

[0059] (3) 10 g acid anhydride montmorillonite, 13.9 g perfluorodecanol is added to 100 mL tetrahydrofuran, then 1.39 g 4-dimethylaminopyridine is added, and the reaction is carried out under reflux at 65 °C under nitrogen atmosphere for 6 h while strong stirring is carried out, the product is centrifuged, alcohol washed and dried to obtain modified montmorillonite;

[0060] (4) The raw materials are respectively mixed according to the formula, then respectively melt through three single screw extruders, film forming through the material block connector, die co-extrusion and cooling, and the product is subsequently cooled, shaped, thickness detected, cut online, wound and packaged to obtain the high-strength and high-toughness ultra-thin dry film protective film.

[0061] The core layer is made of the following components: low-density polyethylene 70g, cross-linked polyethylene 20g, cyclic polyolefin 40g, modified montmorillonite 10g; the adhesion layer is made of the following components: low-density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g; the back layer is made of the following components: low-density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g.

[0062] The total thickness of the dry film protective film is <17μm; the thickness of the adhesion layer is 30% of the total thickness; the thickness of the back layer is 40% of the total thickness.

[0063] Example 2

[0064] A preparation method of a high-strength and high-toughness ultra-thin dry film protective film, comprising the following steps:

[0065] (1) Calcining montmorillonite at 560℃ for 2.5h in an air atmosphere, and then cooling to room temperature to obtain activated montmorillonite;

[0066] (2) Adding 10g of activated montmorillonite and 10.8g of hexadecyl succinic anhydride into 100mL of toluene, stirring and reacting at 77℃ under a nitrogen atmosphere for 7h while ultrasonic treatment is performed, centrifuging the product, alcohol washing and drying to obtain anhydride-modified montmorillonite;

[0067] (3) Adding 10g of anhydride-modified montmorillonite and 12.4g of perfluorodecanol into 100mL of tetrahydrofuran, then adding 1.08g of 4-dimethylaminopyridine, refluxing and reacting at 64℃ under a nitrogen atmosphere for 7h while strong stirring is performed, centrifuging the product, alcohol washing and drying to obtain modified montmorillonite;

[0068] (4) The raw materials are respectively mixed according to the formula, then respectively melt through three single screw extruders, film forming through the material block connector, die co-extrusion and cooling, and the product is subsequently cooled, shaped, thickness detected, cut online, wound and packaged to obtain the high-strength and high-toughness ultra-thin dry film protective film.

[0069] The core layer is made of the following components: low density polyethylene 60g, crosslinked polyethylene 16g, cyclic polyolefin 34g, modified montmorillonite 8g; the fit layer is made of the following components: low density polyethylene 26g, metallocene polyethylene 70g, cyclic polyolefin 17g, diatomite 0.4g; the back layer is made of the following components: low density polyethylene 24g, metallocene polyethylene 70g, cyclic polyolefin 16g, diatomite 0.4g.

[0070] The total thickness of the dry film protective film is <17μm; the thickness of the fit layer is 30% of the total thickness; the thickness of the back layer is 40% of the total thickness.

[0071] Example 3

[0072] A preparation method of a high-strength high-toughness ultra-thin dry film protective film, comprising the following steps:

[0073] (1) calcining montmorillonite at 520℃ under air atmosphere for 2.5h, and then cooling to room temperature to obtain activated montmorillonite;

[0074] (2) adding 10g of activated montmorillonite and 8.6g of hexadecyl succinic anhydride into 100mL of toluene, stirring and reacting at 74℃ under nitrogen atmosphere for 7h while ultrasonic treatment is carried out, centrifuging, alcohol washing and drying the product to obtain anhydride-modified montmorillonite;

[0075] (3) adding 10g of anhydride-modified montmorillonite and 10.8g of perfluorodecanol into 100mL of tetrahydrofuran, and then adding 0.77g of 4-dimethylaminopyridine, refluxing and reacting at 62℃ under nitrogen atmosphere for 8h while strong stirring is carried out, centrifuging, alcohol washing and drying the product to obtain modified montmorillonite;

[0076] (4) mixing raw materials according to the formula respectively, then melting through three single-screw extruders, co-extruding and cooling through a die to form a film, and then cooling, shaping, thickness detecting, online cutting, winding and packaging to obtain the high-strength high-toughness ultra-thin dry film protective film.

[0077] The core layer is made of the following components: low density polyethylene 50g, crosslinked polyethylene 14g, cyclic polyolefin 26g, modified montmorillonite 6g; the fit layer is made of the following components: low density polyethylene 16g, metallocene polyethylene 60g, cyclic polyolefin 14g, diatomite 0.3g; the back layer is made of the following components: low density polyethylene 14g, metallocene polyethylene 60g, cyclic polyolefin 14g, diatomite 0.3g.

[0078] The total thickness of the dry film protective film is <17μm; the thickness of the fit layer is 30% of the total thickness; the thickness of the back layer is 40% of the total thickness.

[0079] Example 4

[0080] A method for preparing a high-strength, high-toughness, ultra-thin dry film protective film includes the following steps:

[0081] (1) Calcine montmorillonite at 500°C in air for 3 hours, and then cool it to room temperature to obtain activated montmorillonite;

[0082] (2) 10g of activated montmorillonite and 6.5g of hexadecyl succinic anhydride were added to 100mL of toluene and stirred at 70℃ under a nitrogen atmosphere for 8h. At the same time, the mixture was subjected to ultrasonic treatment. The product was centrifuged, washed with alcohol, and dried to obtain anhydride-modified montmorillonite.

[0083] (3) Add 10g of acid-anhydride montmorillonite and 9.3g of perfluorodecaol to 100mL of tetrahydrofuran, then add 0.465g of 4-dimethylaminopyridine, reflux at 60℃ under nitrogen atmosphere for 9h, while stirring vigorously, centrifuge, wash with alcohol and dry the product to obtain modified montmorillonite.

[0084] (4) The raw materials are mixed according to the formula and then melted by three single screw extruders. The film is formed by co-extrusion of the batching block connector, the die head and cooling. The product is then cooled and shaped, thickness detected, online slitting, winding and packaging to obtain the high-strength and high-toughness ultra-thin dry film protective film.

[0085] The core layer is made of the following components: 40g of low-density polyethylene, 10g of cross-linked polyethylene, 20g of cyclic polyolefin, and 3g of modified montmorillonite; the bonding layer is made of the following components: 10g of low-density polyethylene, 50g of metallocene polyethylene, 10g of cyclic polyolefin, and 0.1g of diatomaceous earth; the backing layer is made of the following components: 10g of low-density polyethylene, 50g of metallocene polyethylene, 10g of cyclic polyolefin, and 0.1g of diatomaceous earth.

[0086] The total thickness of the dry film protective film is <17μm; the thickness of the bonding layer is 30% of the total thickness; and the thickness of the backing layer is 40% of the total thickness.

[0087] Comparative Example 1

[0088] A method for preparing a dry film protective film includes the following steps:

[0089] (1) Calcine montmorillonite at 600°C in air for 2 hours, and then cool it to room temperature to obtain activated montmorillonite;

[0090] (2) 10g of activated montmorillonite and 12.9g of hexadecyl succinic anhydride were added to 100mL of toluene and stirred at 80℃ under a nitrogen atmosphere for 6h. At the same time, the mixture was subjected to ultrasonic treatment. The product was centrifuged, washed with alcohol, and dried to obtain anhydride-modified montmorillonite.

[0091] (3) The raw materials are respectively mixed according to the formula, and then respectively melt through three single screw extruders, film forming through the material block connector, die co-extrusion and cooling, and the product is subsequently cooled, shaped, thickness detected, cut online, wound and packaged to obtain the dry film protective film.

[0092] The core layer is made of the following components: low density polyethylene 70g, crosslinked polyethylene 20g, cyclic polyolefin 40g, acid anhydride montmorillonite 10g; the adhesion layer is made of the following components: low density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g; the back layer is made of the following components: low density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g.

[0093] The total thickness of the dry film protective film is <17μm; the thickness of the adhesion layer is 30% of the total thickness; the thickness of the back layer is 40% of the total thickness.

[0094] Comparative Example 2

[0095] A preparation method of a dry film protective film, comprising the following steps:

[0096] (1) Calcining montmorillonite at 600℃ under air atmosphere for 2h, and then cooling to room temperature to obtain activated montmorillonite;

[0097] (2) The raw materials are respectively mixed according to the formula, and then respectively melt through three single screw extruders, film forming through the material block connector, die co-extrusion and cooling, and the product is subsequently cooled, shaped, thickness detected, cut online, wound and packaged to obtain the dry film protective film.

[0098] The core layer is made of the following components: low density polyethylene 70g, crosslinked polyethylene 20g, cyclic polyolefin 40g, activated montmorillonite 10g; the adhesion layer is made of the following components: low density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g; the back layer is made of the following components: low density polyethylene 30g, metallocene polyethylene 80g, cyclic polyolefin 20g, diatomite 0.5g.

[0099] The total thickness of the dry film protective film is <17μm; the thickness of the adhesion layer is 30% of the total thickness; the thickness of the back layer is 40% of the total thickness.

[0100] The protective films prepared from Examples 1-4 and Comparative Examples 1-2 were tested for performance, the thickness of the protective films was measured according to GB / T 6672-2001 "Plastic films and sheets - Determination of thickness - Mechanical method"; the tensile strength and elongation at break of the protective films were tested according to GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General principles", the samples were taken using a strip sampler, the length of the rectangular sample was 150±0.5 mm, the width was 15±0.5 mm, the original gauge length was set to 50 mm, the tensile rate was set to 50 mm / min, the sample was ensured to be free of wrinkles and damage, and was clamped vertically, 3 parallel samples were set for each group; the water vapor transmission amount was tested according to the weight gain method in GB / T1037-2021 "Determination of water vapour transmission rate of plastics - Cup method"; the test temperature was 38℃, the humidity was 90% RH, the preheating time was 2h, the rotation interval was 10 min, and 3 parallel samples were set for each group; the oxygen transmission rate was tested according to GB / T1038.1-2022 "Plastics - Determination of gas transmission properties of films and sheets - Part 1: Differential pressure method"; the test temperature was 23℃, the humidity was 50% RH, the vacuum time was 4h, the sample surface was ensured to be free of contamination and scratches, and 3 parallel samples were set for each group. The specific data is shown in Table 1.

[0101] Table 1 Performance test results of dry film protective film

[0102]

[0103] The above merely provides the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, can make equivalent replacements or changes within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A high-strength and high-toughness ultra-thin dry film protective film, which is composed of a laminating layer, a core layer and a back layer, the core layer being located between the laminating layer and the back layer, characterized in that, The core layer is made of the following components in parts by weight: low density polyethylene 40-70 parts, crosslinked polyethylene 10-20 parts, cyclic polyolefin 20-40 parts, modified montmorillonite 3-10 parts; The back layer is made of the following components in parts by weight: low density polyethylene 10-30 parts, metallocene polyethylene 50-80 parts, cyclic polyolefin 10-20 parts, diatomite 0.1-0.5 parts. The preparation method of the modified montmorillonite comprises the following steps: (1) calcining the montmorillonite and then cooling to room temperature to obtain activated montmorillonite; (2) adding the activated montmorillonite and hexadecyl succinic anhydride into toluene, stirring and reacting under nitrogen protection, centrifuging, alcohol washing and drying the product to obtain anhydride montmorillonite; (3) adding the anhydride montmorillonite and perfluorodecanol into tetrahydrofuran, then adding 4-dimethylaminopyridine, refluxing and reacting under nitrogen atmosphere, centrifuging, alcohol washing and drying the product to obtain modified montmorillonite.

2. The dry film resist of claim 1, wherein The low density polyethylene has a molecular weight of 100,000-300,000; the cyclic polyolefin has a molecular weight of 8,000-30,000 and a glass transition temperature of 50-160℃; the total thickness of the dry film protective film is <17 μm; the thickness of the fit layer is 5-50% of the total thickness; and the thickness of the back layer is 5-50% of the total thickness.

3. The dry film resist of claim 1, wherein In step (1), the calcination condition is calcination at 500-600℃ under air atmosphere for 2-3 h.

4. The dry film resist of claim 1, wherein In step (2), the ratio by weight of the activated montmorillonite to hexadecyl succinic anhydride is 10 g:6.5-12.9 g.

5. The dry film resist of claim 1, wherein In step (2), the stirring and reacting condition is stirring and reacting at 70-80℃ for 6-8 h with ultrasonic treatment.

6. The dry film resist of claim 1, wherein In step (3), the ratio by weight of the anhydride montmorillonite to perfluorodecanol is 10 g:9.3-13.9 g, and the amount of 4-dimethylaminopyridine is 5-10 wt% of the perfluorodecanol.

7. The dry film resist of claim 1, wherein In step (3), the refluxing and reacting condition is refluxing and reacting at 60-65℃ for 6-9 h with strong stirring.

8. A method for preparing the high-strength and high-toughness ultra-thin dry film resist according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: mixing the raw materials according to the formula, respectively melting through three single-screw extruders, film forming through a material block connector, a die head co-extrusion and cooling, and then cooling, shaping, thickness detecting, online cutting, winding and packaging to obtain the high-strength and high-toughness ultra-thin dry film protective film.

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