High-strength anti-static PE film for electronic product packaging

Abstract

The application discloses a kind of high-strength anti-static PE films for electronic product packaging, belongs to polyethylene film manufacturing technical field, including PE film, film outer layer, film middle layer, film inner layer, film middle layer, film outer layer are sequentially arranged along the thickness direction of PE film;PE film is made and includes the following steps: S1, heating to obtain outer layer melt;S2, heating to obtain middle layer melt;S3, heating to obtain core layer melt and skin layer melt;S4, outer layer melt and middle layer melt are co-extrusion blown into film cylinder, while core layer melt and skin layer melt are extruded to form several skin-core fibers and sprayed on the inner wall of film cylinder;S5, after film cylinder is pressed and stacked flat, heat and laminate, cool to obtain PE film;The PE film of the application has anti-static performance by adding anti-static additives, and the internal core layer fiber is used as a skeleton structure, which has better mechanical strength, and improves the protection effect of PE film on electronic products.

Description

Technical Field

[0001] This invention relates to the field of polyethylene film manufacturing technology, and specifically to a high-strength antistatic PE film for electronic product packaging. Background Technology

[0002] Semiconductor products, highly integrated precision electronic components, precision instruments and equipment, medical equipment, and other electronic products all require anti-static packaging materials during transportation. Anti-static films are commonly used to package electronic products to solve the static electricity problem during transportation. However, electronic products also need to be protected from moisture, dust, and other factors during transportation. Currently, anti-static films are usually made of polyethylene, which has low strength and is easily damaged under external force. Once the anti-static film used as packaging is damaged, moisture, dust, and other impurities in the environment may enter the packaging through the damaged area and come into contact with the electronic products, thus adversely affecting them. Therefore, the strength of the anti-static film is also very important.

[0003] Chinese Patent CN116515144A discloses a double-sided corona-treated, double-sided antistatic blown polyethylene film and its production process and unit. The polyethylene film substrate is composed of LDPE, POE, LLDPE, metallocene polyethylene, and HDPE. The production process of the polyethylene film includes the following steps: (a) the raw materials of the above-mentioned polyethylene film substrate are mixed evenly and fed into a twin-screw extruder for heating and melting. The melted material is extruded from the blown film machine and cooled by an air ring at the same time; (b) the cylindrical film is stacked into a planar shape by clamping plates; (c) under the traction of the traction roller, the film is stretched longitudinally and a cutting blade is set on both sides of the traction roller; (d) after the blown film is cut, the two sides of the film are immediately corona-treated by the inner corona device; (e) after corona treatment, the film is wound up and impurities on the surface of the polyethylene substrate are removed; (f) an antistatic coating is applied to the surface of the polyethylene substrate, and the inner and outer double coatings are dried by a double drying tunnel before being wound up.

[0004] The aforementioned polyethylene film exhibits good antistatic properties through double-sided corona treatment and coating with an antistatic agent layer. However, the polyethylene film substrate has a single-layer structure, resulting in generally poor mechanical strength. When used as packaging for electronic products, it is prone to damage, which can reduce its waterproof and dustproof properties. Currently, multi-layer co-extrusion processes are commonly used to increase the mechanical strength of polyethylene films. However, among various synthetic resins, polyethylene materials generally exhibit average mechanical strength, such as impact strength and toughness. Even polyethylene films produced through multi-layer co-extrusion processes are difficult to achieve excellent mechanical strength. Therefore, there is still room for improvement in this polyethylene film. Summary of the Invention

[0005] To address the technical deficiencies in the background art, this invention proposes a high-strength antistatic PE film for electronic product packaging, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows: A high-strength antistatic PE film for packaging electronic products includes a PE film and an outer layer, a middle layer, an inner layer, and an outer layer arranged sequentially along the thickness direction of the PE film. The outer layer comprises the following components by mass percentage: 70%-85% high-density polyethylene, 7%-15% metallocene polyethylene, 5%-13% low-density polyethylene, and 0.1%-2% antistatic additives. The membrane middle layer comprises the following components by weight percentage: 70%-90% linear low-density polyethylene, 8%-28% low-density polyethylene, and 0.1%-2% antistatic additive; The inner layer of the membrane is composed of a plurality of core-sheath fibers stacked together. The core-sheath fibers consist of an inner core layer fiber and a surface sheath fiber, with a mass ratio of core layer fiber to sheath fiber of 1:2 to 1:1. The core layer fiber comprises the following components by mass percentage: 95%-98% polypropylene, 1%-5% toughening filler, and 0.1%-0.5% dispersant. The sheath fiber comprises the following components by mass percentage: 50%-70% high-density polyethylene, 10%-25% linear low-density polyethylene, 10%-25% low-density polyethylene, and 0.1%-2% antistatic agent. The production of the PE film includes the following steps: S1. Mix and stir all components of the outer layer of the membrane until they are homogeneous, then heat to a molten state to obtain the outer layer melt; S2. Mix and stir all components of the middle layer of the membrane until they are homogeneous, and then heat to a molten state to obtain the middle layer melt. S3. Mix and stir all components of the core fiber evenly, then heat to a molten state to obtain the core melt; mix and stir all components of the sheath fiber evenly, then heat to a molten state to obtain the sheath melt. S4. The outer layer melt and the middle layer melt are co-extruded in a double layer at the die head and blown into a film tube by airflow. At the same time, the core layer melt and the skin layer melt are extruded at the die head through several triaxial spinning needles to form several core-skin fibers. The core-skin fibers are evenly sprayed on the inner wall of the film tube under the traction of airflow. S5. After the membrane tubes are flattened, they are heated for lamination. During the lamination process, the core fibers adhere to each other to form the inner layer of the membrane and adhere to the middle layer of the membrane. After the material cools down, it is treated with corona to obtain the PE membrane.

[0006] As a further technical solution of the present invention, the outer layer accounts for 30%-40% of the total mass of the PE film, the middle layer accounts for 10%-20% of the total mass of the PE film, and the inner layer accounts for 40%-60% of the total mass of the PE film.

[0007] As a further technical solution of the present invention, the thickness of the PE film is 50-300μm.

[0008] As a further technical solution of the present invention, the antistatic additive is selected from one of the following: antistatic agent GJ1000, antistatic agent A129, antistatic agent 129V, and antistatic agent SAS93.

[0009] As a further technical solution of the present invention, the toughening filler is selected from one or more of nano-silica, nano-calcium carbonate, nano-wollastonite, and nano-talc.

[0010] As a further technical solution of the present invention, the dispersing agent is selected from one or more of polyethylene glycol, propylene glycol block copolymer, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, silane coupling agent, and titanate coupling agent.

[0011] As a further technical solution of the present invention, the inflation ratio of the membrane tube is 2-5 and the traction ratio is 2-5.

[0012] As a further technical solution of the present invention, the heating temperature of the outer layer melt, the middle layer melt, and the skin layer melt before extrusion is 170-190℃, and the heating temperature of the core layer melt before extrusion is 180-220℃.

[0013] As a further technical solution of the present invention, the triaxial spinning needle is provided with three coaxial spinnerets from the axis to the radial surface and ejects core melt, skin melt and high-pressure gas in sequence. The ratio of the ejection speed of the core melt to the skin melt is 1:3-1:1 and the pressure of the high-pressure gas is 1-2 bar.

[0014] As a further technical solution of the present invention, in step S5, the temperature for lamination after the membrane tube is flattened is 120-200℃ and the pressure is 1-2MPa.

[0015] The beneficial effects of this invention are as follows: The PE film of this invention is made based on a multi-layer co-extrusion blow molding process combined with a triaxial spinning process. The PE film consists of multiple layers of polyethylene film and a layer of core-sheath fiber stacked together. The polyethylene film and the fiber film use different components and ratios and are firmly bonded to each other, giving the PE film good comprehensive performance. The fiber film contains a core layer fiber with polypropylene as its main component, which serves as the skeleton structure of the PE film. Through the excellent mechanical strength, heat resistance, and stability of polypropylene, the PE film can better withstand external impact and tension while maintaining structural stability. Thus, when the PE film is used as outer packaging for electronic products, it can prevent static electricity accumulation while better withstanding external impact and tension, thereby improving the protective effect of the PE film on electronic products. Detailed Implementation

[0016] The embodiments of the present invention will be described below with reference to relevant examples. The embodiments of the present invention are not limited to the following examples, and the present invention relates to relevant necessary components in this technical field, which should be regarded as well-known technology in this technical field and can be known and mastered by those skilled in this technical field.

[0017] A high-strength antistatic PE film for electronic product packaging includes a PE film and an outer layer, a middle layer, an inner layer, and an outer layer arranged sequentially along the thickness direction of the PE film. The outer layer is characterized by comprising the following components by mass percentage: 70%-85% high-density polyethylene, 7%-15% metallocene polyethylene, 5%-13% low-density polyethylene, and 0.1%-2% antistatic additives. The membrane middle layer comprises the following components by weight percentage: 70%-90% linear low-density polyethylene, 8%-28% low-density polyethylene, and 0.1%-2% antistatic additives; The inner layer of the membrane is composed of stacked core-sheath fibers, which consist of inner core fibers and outer sheath fibers. The mass ratio of core fibers to sheath fibers is 1:2 to 1:1. The core fibers include the following components by mass percentage: 95%-98% polypropylene, 1%-5% toughening filler, and 0.1%-0.5% dispersant. The sheath fibers include the following components by mass percentage: 50%-70% high-density polyethylene, 10%-25% linear low-density polyethylene, 10%-25% low-density polyethylene, and 0.1%-2% antistatic agent. The production of PE film includes the following steps: S1. Mix and stir all components of the outer layer of the membrane until they are homogeneous, then heat to a molten state to obtain the outer layer melt; S2. Mix and stir all components of the middle layer of the membrane until they are homogeneous, and then heat to a molten state to obtain the middle layer melt. S3. Mix and stir all components of the core fiber evenly, then heat to a molten state to obtain the core melt; mix and stir all components of the sheath fiber evenly, then heat to a molten state to obtain the sheath melt. S4. The outer layer melt and the middle layer melt are co-extruded in a double layer at the die head and blown into a film tube by airflow. At the same time, the core layer melt and the skin layer melt are extruded at the die head through several triaxial spinning needles to form several core-skin fibers. The core-skin fibers are evenly sprayed on the inner wall of the film tube under the traction of airflow. S5. After the membrane tubes are flattened, they are heated for lamination. During the lamination process, the core fibers adhere to each other to form the inner layer of the membrane and adhere to the middle layer of the membrane. After the material cools down, it is treated with corona to obtain the PE membrane.

[0018] The PE film of this invention is a multilayer composite film manufactured based on a multilayer co-extrusion blow molding process. The outer layer, as the outer surface layer of the PE film, is evenly distributed on the outer surface and encloses the middle and inner layers. The middle layer, as the middle layer of the PE film, has its outer surface enclosed by the outer layer and encloses the inner layer. The inner layer is the core layer of the PE film. This is because in the PE film manufacturing process of this invention, the outer and middle melts are first extruded through double-layer co-extrusion and formed at the edge of the die. Then, under the action of airflow, it is blown to form a cylindrical, double-layered film tube. The film tube includes an outer layer surrounding the outer surface and a middle layer surrounding the inner wall. After the film tube is formed, it is stretched and transported by traction rollers. Simultaneously, at the center of the die, several triaxial spinning needles extrude the core melt and skin melt while simultaneously spraying high-pressure airflow. The triaxial spinning needles... Three spinnerets on the radial surface eject core melt, skin melt, and high-pressure airflow, respectively. The high-pressure airflow pulls the melt to form a core-skin fiber structure, where the skin fibers wrap around the fibers. Several core-skin fibers are evenly sprayed onto the inner wall of the newly formed membrane tube, i.e., the inner side of the membrane interlayer, so that a fiber membrane composed of several core-skin fibers is evenly attached to the inner side of the membrane interlayer. Then, while the membrane tube is cooled by the outside cold air, it is transported by the traction roller to the herringbone plate for lamination. The membrane tube is folded into a flat folded membrane. The thickness direction of the folded membrane consists of an outer membrane layer, a membrane interlayer, a fiber membrane, another fiber membrane, a membrane interlayer, and an outer membrane layer. Then, the folded membrane is reheated until the membrane interlayer and skin fibers melt, and then pressure is applied by the rollers for rolling. After rolling, the two fiber membrane layers will bond together to form the inner membrane layer, and the inner membrane layer and the membrane interlayer will also bond together, completing the lamination process. Then, it is cooled and wound up to obtain the PE film.

[0019] Further, the outer layer comprises the following components by mass percentage: 78% high-density polyethylene, 11% metallocene polyethylene, 10% low-density polyethylene, and 1% antistatic agent; the middle layer comprises the following components by mass percentage: 80% linear low-density polyethylene, 19% low-density polyethylene, and 1% antistatic agent; in the core-sheath fiber, the mass ratio of core fiber to sheath fiber is 1:1; the core fiber comprises the following components by mass percentage: 97.8% polypropylene, 2% toughening filler, and 0.2% dispersing agent; the sheath fiber comprises the following components by mass percentage: 60% high-density polyethylene, 20% linear low-density polyethylene, 19% low-density polyethylene, and 1% antistatic agent.

[0020] It should be noted that different types of polyethylene impart different properties to the various layers of a PE film. High-density polyethylene (HDPE) can improve the mechanical strength, abrasion resistance, and barrier properties of the film, thus enabling the film to better withstand external impacts, tension, and prevent moisture penetration from the air. Linear low-density polyethylene (LDPE) can improve the mechanical strength, processability, and barrier properties of the film, thus enabling the film to better withstand external impacts, tension, and be better processed and shaped, as well as prevent moisture penetration from the air. Low-density polyethylene (LDPE) can increase the flexibility and heat-sealing properties of the film, making it suitable for packaging of various shapes and sizes and easy to bond by heat, thereby making it easier for the layers of the PE film to bond and fix together. Metallocene polyethylene (MCPE) can improve the overall performance, mechanical strength, toughness, and gloss of the film, thus enabling the film to better withstand external impacts, tension, and be easy to bond by heat. In addition, antistatic agents prevent the accumulation of static electricity in PE films by forming a conductive layer on the film surface and reducing friction, thus preventing damage to electronic products when used as outer packaging.

[0021] The various layers of a PE membrane achieve different properties through the use of different components and proportions. The outer layer, located on the outside of the PE membrane, is the first to come into contact with external objects, moisture, and dust in the air. By adding a high proportion of high-density polyethylene, the outer layer possesses excellent mechanical strength, abrasion resistance, and barrier properties, enabling the PE membrane to better withstand external impacts, tension, and prevent moisture penetration. The middle layer is mainly composed of linear low-density polyethylene and low-density polyethylene, exhibiting good processing and heat-sealing properties. This allows for better bonding between the middle and outer layers, and during the lamination of folded films, the middle and inner layers can bond more effectively, improving the overall bonding strength of the PE membrane layers. The outer fiber layer is mainly composed of high-density polyethylene. The PE film is composed of polypropylene and contains a high proportion of linear low-density polyethylene and low-density polyethylene. Therefore, the outer layer fiber has good mechanical strength, processing performance, and heat-sealing performance. The outer layer fiber can ensure the mechanical strength of the inner layer of the film while bonding well with the middle layer and core layer fibers, improving the bonding strength between the various film layers in the PE film. In addition, polypropylene has excellent mechanical strength, heat resistance, and stability. The core layer fiber is mainly composed of polypropylene. The core layer fiber can act as the internal skeleton structure of the PE film. The excellent mechanical strength of the core layer fiber enables the PE film to better withstand external impact and tension, and maintain the structural stability of the PE film after withstanding external impact and tension. Therefore, the PE film is not easily damaged when used as outer packaging for electronic products.

[0022] In summary, the PE film of this invention is manufactured based on a multi-layer co-extrusion blow molding process combined with a triaxial spinning process. The PE film consists of multiple layers of polyethylene film and a layer of core-sheath fiber stacked together. The polyethylene film and the fiber film use different components and ratios and are firmly bonded to each other, giving the PE film excellent comprehensive performance. The fiber film contains a core layer fiber with polypropylene as its main component, which serves as the skeleton structure of the PE film. Through the excellent mechanical strength, heat resistance, and stability of polypropylene, the PE film can better withstand external impacts and tension while maintaining structural stability. Thus, when used as outer packaging for electronic products, the PE film can prevent static electricity accumulation while better withstanding external impacts and tension, thereby improving the protective effect of the PE film on electronic products.

[0023] As one of the preferred embodiments of the present invention, the outer layer accounts for 30%-40% of the total mass of the PE film, the middle layer accounts for 10%-20% of the total mass of the PE film, and the inner layer accounts for 40%-60% of the total mass of the PE film.

[0024] In the PE film of this invention, the outer layer accounts for 35% of the total mass of the PE film, the middle layer accounts for 15%, and the inner layer accounts for 50%. The outer layer, being the first layer to come into contact with external objects and moisture and dust in the air, possesses good mechanical strength, abrasion resistance, and barrier properties. Its 35% weight ensures the protective strength of the PE film surface. The middle layer, connecting the outer and inner layers, primarily enhances the bonding strength between the internal layers through processing and heat-sealing properties; therefore, its proportion in the PE film does not need to be too high. The inner layer further improves the mechanical strength and structural stability of the PE film through its internal core fibers. A higher proportion of the inner layer significantly enhances these properties, thereby improving the protective effect of the PE film on electronic products.

[0025] As one of the preferred embodiments of the present invention, the blow-up ratio of the membrane tube is 2-5, the traction ratio is 2-5, and the thickness of the PE membrane is 50-300μm.

[0026] In the PE film manufacturing process of this invention, the blow-up ratio and traction ratio of the film tube mainly affect the strength of the film tube under transverse and longitudinal stretching. Different thicknesses of PE film can be obtained by using different blow-up ratios and traction ratios.

[0027] As one of the preferred embodiments of the present invention, the antistatic additive is selected from one of the following: antistatic agent GJ1000, antistatic agent A129, antistatic agent 129V, and antistatic agent SAS93.

[0028] The antistatic additive of the present invention imparts antistatic properties to the outer layer, middle layer and inner layer of the film by forming a conductive layer and reducing friction. Under normal circumstances, the antistatic additive will not be mixed with other components of the outer layer, middle layer and skin fiber for drying, so as to avoid the antistatic additive melting in advance and adhering to the inner wall of the hopper of the drying equipment. Instead, the antistatic additive is mixed before the raw materials are mixed and heated to melt.

[0029] As one of the preferred embodiments of the present invention, the toughening filler is selected from one or more of nano-silica, nano-calcium carbonate, nano-wollastonite, and nano-talc.

[0030] The toughening filler of this invention can increase the modulus of the core fiber, that is, enhance the core fiber's ability to resist deformation, and significantly improve the core fiber's toughness, tensile strength, impact strength and other properties. As the skeleton structure inside the PE film, the core fiber can give the PE film better mechanical strength after adding the toughening filler.

[0031] As one of the preferred embodiments of the present invention, the dispersing agent is selected from one or more of polyethylene glycol, propylene glycol block copolymer, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, silane coupling agent, and titanate coupling agent.

[0032] The toughening filler of this invention uses nano-sized particles. The toughening filler is prone to agglomeration in the core layer melt. Therefore, it is necessary to add dispersing aids to promote the dispersion of the toughening filler in the core layer melt and improve the stability of the core layer fiber properties. The dispersing aids promote the uniform dispersion of the toughening filler in the core layer melt by adsorbing on the surface of the toughening filler to form a protective film, releasing ions adsorbed on the surface of the toughening filler, reducing the surface tension of the melt, and forming chemical bonds with the surface groups of the toughening filler.

[0033] As one of the preferred embodiments of the present invention, the heating temperature of the outer melt, middle melt, and skin melt before extrusion is 170-190°C, and the heating temperature of the core melt before extrusion is 180-220°C.

[0034] The outer melt, middle melt, and skin melt of this invention are mainly composed of different types of polyethylene. In order to ensure the processing performance and fluidity of these three melts, heating the melt to 170-190°C helps to form a uniform and defect-free film or fiber. The core melt is mainly composed of polypropylene. Heating the core melt to 180-220°C can improve its fluidity and plasticity, which helps to obtain a uniform and defect-free core fiber.

[0035] As one of the preferred embodiments of the present invention, the triaxial spinning needle is provided with three coaxial spinnerets from the axis to the radial surface, and ejects core melt, skin melt and high-pressure airflow in sequence. The ratio of the ejection speed of core melt to skin melt is 1:3-1:1, and the pressure of high-pressure airflow is 1-2 bar.

[0036] In the triaxial spinning needle of the present invention, the core melt is ejected from the spinneret hole at the center of the axis, while the sheath melt is ejected from the second spinneret hole and wraps around the outer surface of the core melt. Both the core melt and the sheath melt are transformed into slender fibers under the traction of the high-pressure airflow ejected through the third spinneret hole, thus obtaining a core-sheath fiber structure in which the sheath fiber wraps the core fiber. The core-sheath fiber moves to the inner wall of the membrane tube under the action of the high-pressure airflow and forms a fiber membrane through attachment and stacking. The fiber membrane is the precursor structure for forming the inner membrane layer of the PE membrane. By adjusting the ratio of the ejection speed of the core melt to the sheath melt and the pressure of the high-pressure airflow, the ratio of the core fiber to the sheath fiber in the core-sheath fiber and the diameter, morphology and other properties of the core-sheath fiber can be adjusted, thereby adjusting various properties of the inner membrane layer.

[0037] As one of the preferred embodiments of the present invention, in step S5, the temperature for lamination after the membrane tube is flattened is 120-200℃ and the pressure is 1-2MPa.

[0038] The purpose of this invention is to laminate the membrane tube to bond the two inner fiber membranes together to form the inner membrane layer and to bond and fix the inner membrane layer to the middle membrane layer. Therefore, the heating temperature during the lamination process needs to reach the melting temperature of polyethylene, so that the middle membrane layer and the outer layer fibers have a certain degree of fluidity and plasticity, thereby achieving mutual adhesion of the membrane layers. In addition, the lamination temperature can be heated to the melting temperature of polypropylene, so that the core layer fibers also have a certain degree of fluidity and plasticity, making the core layer fibers and the outer layer fibers more firmly bonded, which is beneficial to increasing the structural stability of the inner membrane layer.

[0039] The present invention will be further illustrated below through examples and comparative examples.

[0040] Example 1

[0041] S1. Mix 78% high-density polyethylene, 11% metallocene polyethylene, 10% low-density polyethylene, and 1% antistatic additive by mass percentage, stir evenly, and heat to a molten state to obtain the outer melt. S2. Mix 80% linear low-density polyethylene, 19% low-density polyethylene, and 1% antistatic additive by mass percentage, stir evenly, and heat to a molten state to obtain the middle layer melt. S3. Mix 97.8% polypropylene, 2% toughening filler, and 0.2% dispersant by mass percentage, stir evenly, and heat to a molten state to obtain the core layer melt. Mix 60% high-density polyethylene, 20% linear low-density polyethylene, 19% low-density polyethylene, and 1% antistatic additive by mass percentage, stir evenly, and heat to a molten state to obtain the skin layer melt. S4. The outer layer melt and the middle layer melt are co-extruded in a double layer at the die head and blown into a film tube by airflow. At the same time, the core layer melt and the skin layer melt are extruded at the die head at a mass ratio of 1:1 through several triaxial spinning needles to form several core-skin fibers. The core-skin fibers are evenly sprayed on the inner wall of the film tube under the traction of airflow. S5. After the membrane tubes are flattened, they are heated for lamination. During the lamination process, the core fibers adhere to each other to form the inner layer of the membrane and adhere to the middle layer of the membrane. After the material cools down, it is treated with corona to obtain the PE membrane. The proportions of the outer layer, middle layer and inner layer of the membrane to the total mass of the PE membrane are 35%, 15% and 50%, respectively.

[0042] Example 2

[0043] The difference between this embodiment and the above embodiment 1 is that in step S4, the core melt and the sheath melt are extruded at the die head through several triaxial spinning needles at a mass ratio of 1:2 to form several core-sheath fibers; other components, proportions and operating steps are the same.

[0044] Example 3

[0045] The difference between this embodiment and the above embodiment 1 is that in step S3, 94.5% polypropylene, 5% toughening filler and 0.5% dispersant by mass percentage are mixed and stirred evenly and then heated to a molten state to obtain the core layer melt; other components, proportions and operating steps are the same.

[0046] Comparative Example 1 The difference between this embodiment and Embodiment 1 above is that in step S3, the core layer melt is 100% polypropylene; the other components, proportions, and operating steps are the same.

[0047] Comparative Example 2 Referring to Example 1 of the specification of Chinese Patent No. CN116515144A, a blown polyethylene film with double-sided corona discharge and double-sided antistatic properties, and its production process and unit (publication number: CN116515144A), the PE film of this comparative example was obtained according to the blown polyethylene film production method provided by the patent.

[0048] Comparative Example 3 Referring to the preparation method of antistatic polyethylene film disclosed in Chinese patent (publication number: CN116535758A), the PE film of this comparative example was obtained according to the preparation method.

[0049] It should be noted that the thickness of the PE film obtained in all the above embodiments and comparative examples is 200 μm.

[0050] The PE films obtained from all the above embodiments and comparative examples were subjected to the following tests: longitudinal elongation at break and transverse elongation at break were tested according to the content of standard document GB / T1040.1-2006; tensile strength was tested according to the content of standard document GB / T13735-2017; dart impact performance was tested according to the content of standard document GB9639.1-2008; and electrostatic discharge time of the PE film was tested.

[0051] The results of all the above tests are shown in Table 1 below:

[0052] Table 1 According to the data in Table 1, all the PE films obtained in the above embodiments and comparative examples have good antistatic properties. Comparing the test results of all examples 1-3, the PE films of examples 1-3 are obtained based on the technical solution of this invention. Since most of the core and sheath fibers in the inner layer of the film are longitudinally distributed, the longitudinal breaking elongation of the PE film is higher than the transverse breaking elongation, and the PE film can better withstand longitudinal tension. Example 2 reduced the proportion of melt formation compared to Example 1, while Example 3 increased the addition ratio of toughening filler compared to Example 1. Specifically, the mechanical strength of the PE film of Example 1 is significantly better than that of Example 2, while the mechanical strength of the PE film of Example 3 is not significantly improved compared to that of Example 1. Combined with the test results of Comparative Example 1, the proportion of core fiber in the core and sheath fibers has a significant impact on the mechanical strength of the PE film. It is recommended that the mass ratio of core fiber to sheath fiber be 1:1. After adding 2% toughening filler to the core fiber, the mechanical strength of the PE film is significantly improved. However, further increasing the content of toughening filler will not significantly improve the mechanical strength of the PE film. Therefore, it is recommended that the amount of toughening filler added to the core fiber be about 2%.

[0053] Comparing the test results of all embodiments and comparative examples, it can be seen that the mechanical strength of the PE film in embodiments 1-3 based on the technical solution of the present invention is better than that of comparative examples 1-3. In the scheme of comparative example 3, the PE film is made by a three-layer co-extrusion process, so the mechanical strength of the PE film in comparative example 3 is better than that of comparative example 2. It can be seen that the PE film made based on the technical solution of the present invention has good mechanical strength, thus providing better protection for electronic products.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength antistatic PE film for packaging electronic products, comprising a PE film, an outer layer, a middle layer, an inner layer, and an outer layer arranged sequentially along the thickness direction of the PE film, characterized in that, The outer membrane layer comprises the following components by weight percentage: 70%-85% high-density polyethylene, 7%-15% metallocene polyethylene, 5%-13% low-density polyethylene, and 0.1%-2% antistatic additive; The membrane middle layer comprises the following components by weight percentage: 70%-90% linear low-density polyethylene, 8%-28% low-density polyethylene, and 0.1%-2% antistatic additive; The inner layer of the membrane is composed of a plurality of core-sheath fibers stacked together. The core-sheath fibers consist of an inner core layer fiber and a surface sheath fiber, with a mass ratio of core layer fiber to sheath fiber of 1:2 to 1:

1. The core layer fiber comprises the following components by mass percentage: 95%-98% polypropylene, 1%-5% toughening filler, and 0.1%-0.5% dispersant. The sheath fiber comprises the following components by mass percentage: 50%-70% high-density polyethylene, 10%-25% linear low-density polyethylene, 10%-25% low-density polyethylene, and 0.1%-2% antistatic agent. The production of the PE film includes the following steps: S1. Mix and stir all components of the outer layer of the membrane until they are homogeneous, then heat to a molten state to obtain the outer layer melt; S2. Mix and stir all components of the middle layer of the membrane until they are homogeneous, and then heat to a molten state to obtain the middle layer melt. S3. Mix and stir all components of the core fiber evenly, then heat to a molten state to obtain the core melt; mix and stir all components of the sheath fiber evenly, then heat to a molten state to obtain the sheath melt. S4. The outer layer melt and the middle layer melt are co-extruded in a double layer at the die head and blown into a film tube by airflow. At the same time, the core layer melt and the skin layer melt are extruded at the die head through several triaxial spinning needles to form several core-skin fibers. The core-skin fibers are evenly sprayed on the inner wall of the film tube under the traction of airflow. S5. After the membrane tubes are flattened, they are heated for lamination. During the lamination process, the core fibers adhere to each other to form the inner layer of the membrane and adhere to the middle layer of the membrane. After the material cools down, it is treated with corona to obtain the PE membrane.

2. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The outer layer accounts for 30%-40% of the total mass of the PE film, the middle layer accounts for 10%-20% of the total mass of the PE film, and the inner layer accounts for 40%-60% of the total mass of the PE film.

3. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The thickness of the PE film is 50-300 μm.

4. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The antistatic additive is selected from one of the following: antistatic agent GJ1000, antistatic agent A129, antistatic agent 129V, and antistatic agent SAS93.

5. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The toughening filler is selected from one or more of nano-silica, nano-calcium carbonate, nano-wollastonite, and nano-talc.

6. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The dispersing agent is selected from one or more of polyethylene glycol, propylene glycol block copolymer, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, silane coupling agent, and titanate coupling agent.

7. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The inflation ratio and traction ratio of the membrane tube are 2-5.

8. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The outer layer melt, middle layer melt, and skin layer melt are heated to 170-190℃ before extrusion, and the core layer melt is heated to 180-220℃ before extrusion.

9. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, The triaxial spinning needle has three coaxial spinnerets arranged sequentially from the axis to the radial surface, which sequentially eject core melt, skin melt, and high-pressure gas. The ratio of the ejection speed of the core melt to the skin melt is 1:3 to 1:1, and the pressure of the high-pressure gas is 1-2 bar.

10. The high-strength antistatic PE film for electronic product packaging according to claim 1, characterized in that, In step S5, the lamination temperature after the membrane tube is flattened is 120-200℃ and the pressure is 1-2MPa.

Images