High-tension BOPP film

Abstract

The utility model discloses a high-tension BOPP (biaxially-oriented polypropylene) film, which belongs to the technical field of BOPP films, and is characterized in that the high-tension BOPP film comprises an upper surface layer, a middle layer and a lower surface layer, the upper surface layer is arranged at the top of the middle layer, the lower surface layer is arranged at the bottom of the middle layer, the upper surface layer and the lower surface layer are anti-adhesion polypropylene layers, the thickness of the upper surface layer and the thickness of the lower surface layer are 3-8 microns, and the thickness of the middle layer is 3-8 microns. The surface of the upper surface layer and the surface of the lower surface layer are both provided with micro-convex textures, the height of the micro-convex textures is 0.5-1.5 microns, the distance between every two adjacent micro-convex textures is 10-20 microns, adhesion between layers of the thin film can be effectively prevented through the anti-adhesion polypropylene layers of the upper surface layer and the lower surface layer, the thin film is easier to unfold and operate in the rolling, storing and using processes, and the service life of the thin film is prolonged. The micro-convex textures can properly increase the friction force between the film and the surfaces of other objects while keeping the adhesion resistance, so that the film can be stably conveyed and positioned on packaging equipment conveniently, the accuracy and efficiency of the packaging process are improved, the film can be better matched with mechanical parts, and the phenomena of deviation and blockage are reduced.

Description

Technical Field

[0001] This utility model relates to the field of BOPP film technology, and in particular to a high-tensile BOPP film. Background Technology

[0002] BOPP film is widely used in the packaging industry, but existing BOPP film technology still has many shortcomings.

[0003] In terms of tensile properties, many traditional BOPP films are unable to withstand large tensile forces. Their tensile strength is limited in both the longitudinal and transverse directions. In scenarios with high tensile requirements, such as industrial heavy product packaging and high-speed automated packaging machinery, problems such as film breakage and tensile deformation are likely to occur, which cannot meet the needs of the modern packaging industry for high-strength films.

[0004] Therefore, a high-tensile BOPP film is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a high-tensile BOPP film that can solve the problem that existing BOPP films cannot withstand large tensile forces and have limited tensile strength in both the longitudinal and transverse directions. In scenarios with high tension requirements, such as industrial heavy product packaging and high-speed automated packaging machinery, the film is prone to breakage and tensile deformation.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a high-tensile BOPP film, comprising an upper surface layer, an intermediate layer, and a lower surface layer, wherein the upper surface layer is disposed on top of the intermediate layer, and the lower surface layer is disposed at the bottom of the intermediate layer. Both the upper and lower surface layers are anti-adhesion polypropylene layers with a thickness of 3-8 μm, and both the upper and lower surface layers have micro-protrusion textures on their surfaces, with a height of 0.5-1.5 μm and a spacing of 10-20 μm between adjacent micro-protrusions.

[0007] Preferably, the intermediate layer is a composite reinforcing layer, comprising a biaxially oriented polypropylene matrix and aramid fibers and glass fibers dispersed therein, wherein the diameter of the aramid fibers and glass fibers is 8-18 μm, the mass ratio of aramid fibers to glass fibers is 1:1-2:1, and the total mass of the fibers accounts for 6-12% of the mass of the intermediate layer.

[0008] Preferably, the upper surface layer is coated with an antistatic and wear-resistant coating on the side away from the middle layer. The thickness of the antistatic and wear-resistant coating is 1-3 μm, and the antistatic and wear-resistant coating is composed of conductive polyaniline, silicon carbide micro powder and polyurethane resin.

[0009] Preferably, a heat-sealing layer is provided on the side of the lower surface layer away from the middle layer, and the heat-sealing layer is made of low-density polyethylene material with a thickness of 2-5 μm.

[0010] Preferably, the intermediate layer is subjected to ultraviolet irradiation crosslinking treatment with an irradiation dose of 30-60 kGy.

[0011] Preferably, the longitudinal tensile strength of the film is 300-400 MPa, and the transverse tensile strength is 250-350 MPa.

[0012] Preferably, the haze of the film is less than 1.2% and the gloss is greater than 95.

[0013] Preferably, the water vapor permeability of the membrane is less than 20 g / (m2·24h).

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] The anti-adhesion polypropylene layers on the upper and lower surfaces of this application effectively prevent film layers from sticking together, making the film easier to unwind and handle during winding, storage, and use. The micro-protruding texture, while maintaining anti-adhesion properties, can moderately increase the friction between the film and other object surfaces, facilitating stable transmission and positioning on packaging equipment and improving the accuracy and efficiency of the packaging process. For example, on high-speed packaging lines, the film can better cooperate with mechanical parts, reducing deviation and jamming. Attached Figure Description

[0016] Figure 1 This is an overall structural diagram of the high-tensile BOPP film of this utility model;

[0017] Figure 2 This is a schematic diagram of the connection of the upper surface layer of this utility model;

[0018] Figure 3 This is a schematic diagram showing the position of the lower surface layer of this utility model.

[0019] In the diagram, 1 is the upper surface layer; 2 is the middle layer; 3 is the lower surface layer; 4 is the antistatic and wear-resistant coating; and 5 is the heat-sealing layer. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1-3 The present invention provides the following technical solution:

[0022] A high-tensile BOPP film includes an upper surface layer 1, an intermediate layer 2, and a lower surface layer 3. The upper surface layer 1 is disposed on top of the intermediate layer 2, and the lower surface layer 3 is disposed at the bottom of the intermediate layer 2. Both the upper surface layer 1 and the lower surface layer 3 are anti-blocking polypropylene layers with a thickness of 3-8 μm. The surfaces of both the upper surface layer 1 and the lower surface layer 3 are provided with micro-protrusion textures. The height of the micro-protrusion textures is 0.5-1.5 μm, and the spacing between adjacent micro-protrusions is 10-20 μm.

[0023] In this embodiment: the anti-adhesion polypropylene layers of the upper surface layer 1 and the lower surface layer 3 can effectively prevent the film layers from sticking together, making the film easier to unfold and handle during winding, storage and use. The micro-protrusion texture can moderately increase the friction between the film and other object surfaces while maintaining anti-adhesion properties, which is conducive to stable transmission and positioning on packaging equipment, and improves the accuracy and efficiency of the packaging process. For example, on a high-speed packaging production line, the film can better cooperate with mechanical parts and reduce deviation and jamming.

[0024] Specifically, such as Figure 2 As shown, the intermediate layer 2 is a composite reinforcing layer, comprising a biaxially oriented polypropylene matrix and aramid fibers and glass fibers dispersed therein. The diameter of the aramid fibers and glass fibers is 8-18 μm, the mass ratio of aramid fibers to glass fibers is 1:1-2:1, and the total mass of the fibers accounts for 6-12% of the mass of the intermediate layer 2.

[0025] Specifically, such as Figure 2 As shown, the upper surface layer 1 is coated with an antistatic wear-resistant coating 4 on the side away from the middle layer 2. The thickness of the antistatic wear-resistant coating 4 is 1-3 μm. The antistatic wear-resistant coating 4 is composed of conductive polyaniline, silicon carbide micro powder and polyurethane resin.

[0026] Specifically, such as Figure 3 As shown, a heat-sealing layer 5 is provided on the side of the lower surface layer 3 away from the middle layer 2. The heat-sealing layer 5 is made of low-density polyethylene material with a thickness of 2-5μm.

[0027] In this embodiment: the composite reinforcement structure of aramid fiber and glass fiber in the intermediate layer 2 greatly enhances the overall strength of the film. Aramid fiber has high strength, high modulus, and good heat resistance, while glass fiber provides good rigidity and dimensional stability. The synergistic effect of the two enables the film to withstand greater tensile force, significantly enhancing both longitudinal and transverse tensile strength, effectively reducing the risk of film breakage, ensuring the integrity of the packaging and the safety of the product. The conductive polyaniline in the antistatic and wear-resistant coating 4 gives the film excellent antistatic properties, quickly dissipating the static charge accumulated on the film surface and preventing the adsorption of dust, impurities, and other contaminants due to static electricity, thereby maintaining the cleanliness and aesthetics of the packaging. Especially suitable for packaging products sensitive to static electricity, such as electronic components, silicon carbide micro powder provides excellent wear resistance, significantly enhancing the hardness and wear resistance of the film surface, reducing surface scratches and wear during friction with packaging equipment parts and daily handling and storage, extending the service life of the film, and ensuring its long-term stable barrier performance. The heat-sealing layer 5 of the lower surface layer 3 widens the heat-sealing temperature range of the film, enabling reliable heat sealing under different packaging equipment and process conditions. The lower heat-sealing temperature requirement can reduce energy consumption and improve packaging production efficiency, while the higher heat-sealing strength ensures the firmness and sealing of the packaging seal, effectively preventing leakage, moisture, oxidation, etc. of the product inside the packaging.

[0028] Specifically, such as Figure 2 , Figure 3 As shown, the intermediate layer 2 is cross-linked by ultraviolet irradiation with an irradiation dose of 30-60 kGy.

[0029] Specifically, such as Figure 2 , Figure 3 As shown, the longitudinal tensile strength of the film is 300-400 MPa, and the transverse tensile strength is 250-350 MPa.

[0030] In this embodiment, the ultraviolet irradiation crosslinking treatment of the intermediate layer 2 further optimizes the molecular structure of the intermediate layer 2, enhances the bonding force between the fiber and the polypropylene matrix, and makes the structure of the intermediate layer 2 more stable and compact. This treatment method can effectively improve the heat resistance, chemical resistance and dimensional stability of the film. In high-temperature environments or packaging applications that come into contact with chemicals, the film is not easily deformed, degraded or loses strength, ensuring the reliability and durability of the packaging. The high longitudinal tensile strength and transverse tensile strength give the film excellent tensile strength, which can adapt to various complex packaging stress conditions. During the packaging process, whether subjected to longitudinal traction or transverse expansion force, the film can remain intact and is not easily broken or irreversibly deformed, thereby ensuring that the contents of the packaging are properly protected, and also expanding the applicability of the film in different packaging designs and processes.

[0031] Specifically, such as Figure 2 , Figure 3 As shown, the haze of the film is less than 1.2%, and the gloss is greater than 95.

[0032] Specifically, such as Figure 2 , Figure 3 As shown, the water vapor permeability of the membrane is less than 20 g / (m2·24h).

[0033] In this embodiment, the film's optical properties of less than 1.2% haze and greater than 95% give it extremely high transparency and gloss. High transparency allows for clear display of details such as the appearance, shape, and color of the product inside the packaging, while high gloss makes the packaging surface brighter and smoother, enhancing its visual texture. The low water vapor transmittance indicates that the film has good moisture-proof performance, effectively blocking external water vapor from entering the packaging and preventing the product inside from deteriorating, being damaged, or losing its performance due to moisture. It is particularly suitable for packaging products that are sensitive to humidity, such as pharmaceuticals, precision instruments, and dried foods.

[0034] Working principle: First, aramid fibers and glass fibers are thoroughly mixed with biaxially oriented polypropylene raw materials in a high-speed mixer according to a predetermined ratio. Then, the mixture is extruded through an extruder to form the intermediate layer 2 sheet. During the extrusion process, process parameters such as temperature and screw speed are controlled. Next, the anti-adhesion polypropylene raw materials are extruded separately in two other extruders to form the upper surface layer 1 and lower surface layer 3 sheets. The upper surface layer 1, intermediate layer 2, and lower surface layer 3 are then bonded together through a co-extrusion process to form a three-layer film sheet. Afterward, the intermediate layer 2 sheet is subjected to ultraviolet irradiation crosslinking treatment using a specific power ultraviolet irradiation device according to a predetermined irradiation dose. After the upper surface layer 1 is extruded, an antistatic and wear-resistant coating 4 is coated on its surface. Conductive polyaniline, silicon carbide micro powder, and polyurethane resin are mixed evenly in a certain proportion. A coating is prepared by adding an appropriate amount of solvent. The coating is then evenly applied to the upper surface layer 1 using a coating process, with the coating thickness controlled at 1-3 μm. After extrusion of the lower surface layer 3, low-density polyethylene and ethylene-vinyl acetate copolymer are mixed evenly and then laminated to the lower surface layer 3 using a co-extrusion process. The thickness of the heat-sealing layer 5 is controlled at 2-5 μm. Finally, the laminated film undergoes biaxial stretching treatment. First, longitudinal stretching is performed at a temperature controlled at 130-160℃, with a stretch ratio of 4-6 times. Then, transverse stretching is performed at a temperature of 140-170℃, with a stretch ratio of 5-7 times. After stretching, the film undergoes cooling, shaping, and winding processes to obtain a high-tensile BOPP film product. After rigorous performance testing, this film can meet the stringent performance requirements of various high-end packaging applications.

[0035] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-tension BOPP film comprising an upper skin layer (1), an intermediate layer (2) and a lower skin layer (3), characterized in that: The upper surface layer (1) is arranged on the top of the middle layer (2), the lower surface layer (3) is arranged on the bottom of the middle layer (2), the upper surface layer (1) and the lower surface layer (3) are both anti-adhesion polypropylene layers, the thickness is 3-8 microns, and the surfaces of the upper surface layer (1) and the lower surface layer (3) are both provided with micro-protrusion textures, the height of the micro-protrusion textures is 0.5-1.5 microns, and the distance between adjacent micro-protrusions is 10-20 microns.

2. A high tensile BOPP film as claimed in claim 1, wherein: The middle layer (2) is a composite reinforcing layer.

3. A high tensile BOPP film as claimed in claim 1, wherein: The side, away from the middle layer (2), of the upper surface layer (1) is coated with an anti-static wear-resistant coating (4), and the thickness of the anti-static wear-resistant coating (4) is 1-3 microns.

4. A high tensile BOPP film as claimed in claim 1, wherein: The side, away from the middle layer (2), of the lower surface layer (3) is provided with a heat-sealing layer (5), and the heat-sealing layer (5) is made of low-density polyethylene material and has a thickness of 2-5 microns.

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