A winding film and its preparation method

Abstract

The present invention relates to a winding film and a preparation method thereof, belonging to the technical field of film materials. By weight, the winding film comprises the following raw materials: 40-60 parts of a polyethylene base material, 5-10 parts of fluorinated graphene, 0.5-1.0 part of a dispersant, 1-5 parts of a lubricant, and 2-5 parts of a stabilizer; the polyethylene base material is obtained by subjecting ultra-low density polyethylene and ultra-high molecular weight polyethylene with a weight ratio of 100:(11-17) to freeze-thaw cycling treatment and pulsed electron beam irradiation treatment in sequence. The present invention selects ultra-low density polyethylene and ultra-high molecular weight polyethylene with appropriate ratios as the polyethylene base material system, and at the same time introduces freeze-thaw cycling and pulsed electron beam irradiation to jointly modify the polyethylene base material system and uses fluorinated graphene as a filler, achieving a double improvement in the thinning and mechanical properties of the winding film, effectively solving the contradiction between the thinning and performance improvement of the winding film, and making up for the deficiencies of the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of film materials, and in particular to a wrapping film and a preparation method thereof. Background Art

[0002] In the process of packaging, fixing and protecting various items, stretch film is a vital material, and its performance directly affects the packaging efficiency, the safety of items and the transportation cost. Although traditional stretch film has met the basic needs of the market to a certain extent, with the rapid development of the logistics industry and the increasing awareness of environmental protection, more stringent requirements have been put forward for the performance of stretch film. Specifically, the market urgently needs a stretch film that is both light and thin and has excellent mechanical properties, so as to reduce material consumption and reduce costs while ensuring the safety and stability of packaged items.

[0003] However, the existing stretch film often faces the contradiction between thinning and performance improvement. On the one hand, in order to reduce costs and resource consumption, the stretch film needs to be as thin as possible; on the other hand, thinning often leads to a decrease in mechanical properties, such as tensile strength, tear strength, and abrasion resistance, thereby affecting the packaging effect and the safety of the goods. In addition, the traditional stretch film may also have problems such as difficulty in processing, high energy consumption, and environmental pollution during processing.

[0004] In response to the above problems, the industry has made many attempts and improvements, such as improving the performance of stretch film by changing the raw material formula, optimizing the processing technology, etc. However, these improvements can only alleviate the contradiction between thinning and performance improvement to a certain extent, but cannot fundamentally solve this problem.

[0005] Therefore, there is an urgent need for a new type of stretch film and its preparation method, which can significantly improve the mechanical properties while maintaining the light and thin characteristics, and meet the market's urgent demand for high-performance, lightweight stretch film. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a stretch film and a preparation method thereof.

[0007] In a first aspect, the present invention provides a stretch film, wherein the stretch film comprises the following raw materials in parts by weight:

[0008] 40-60 parts of polyethylene base material, 5-10 parts of fluorinated graphene, 0.5-1.0 parts of dispersant, 1-5 parts of lubricant and 2-5 parts of stabilizer;

[0009] The polyethylene base material is obtained by sequentially subjecting ultra-low density polyethylene and ultra-high molecular weight polyethylene in a weight ratio of 100:(11-17) to freeze-thaw cycle treatment and pulse electron beam irradiation treatment;

[0010] The density of the ultra-low density polyethylene is 0.904~0.912 g / cm³;

[0011] The weight-average molecular weight of the ultra-high molecular weight polyethylene is 3 million~5 million.

[0012] Further, by weight, the winding film comprises the following raw materials:

[0013] 52 parts of a polyethylene base material, 7 parts of fluorinated graphene, 0.8 part of a dispersant, 2 parts of a lubricant, and 3.5 parts of a stabilizer.

[0014] Further, the weight ratio of the ultra-low density polyethylene to the ultra-high molecular weight polyethylene is 100:14.5.

[0015] Further, the working condition parameters of the freeze-thaw cycle treatment include: the freezing temperature is -35~-20°C, the freezing time is 60~120 minutes; the thawing temperature is 35~45°C, the thawing time is 60~120 minutes; and the number of cycle treatments is 3~6 times.

[0016] Further, the working condition parameters of the pulsed electron beam irradiation treatment include: the electron beam energy density is 15~40 J / cm, the electron energy is 10 kev, the number of pulses is 3~5 times, the pulse time is 50~90 μs, and the frequency is 0.2~0.6 Hz.

[0017] Further, the dispersant includes at least one of polyvinylpyrrolidone and polyethylene wax, the lubricant includes at least one of ethylene bisstearamide and pentaerythritol stearamide, and the stabilizer includes at least one of dibutyltin dilaurate and octyltin maleate.

[0018] Further, the thickness of the winding film is ≤10 μm.

[0019] In a second aspect, the present invention provides a method for preparing a winding film according to any one of the first aspect, the preparation method comprising the following steps:

[0020] Mix the raw materials in proportion, and then add them to a screw extruder for melt blending to obtain a melt;

[0021] Feed the melt into an extrusion die for co-extrusion, and then successively cool and solidify it through a forming roller and a cooling roller, and draw and wind it through a drawing roller and a winding roller to obtain the winding film.

[0022] Furthermore, the heating temperature of the screw extruder is divided into 8 zones: the temperature of zone I is 275 - 285 °C, the temperature of zone II is 250 - 265 °C, the temperature of zone III is 210 - 220 °C, the temperature of zone IV is 220 - 235 °C, the temperature of zone V is 230 - 245 °C, the temperature of zone VI is 245 - 260 °C, the temperature of zone VII is 260 - 275 °C, and the temperature of zone VIII is 275 - 285 °C; the cooling roller includes a first cooling roller and a second cooling roller, and the temperatures of the first cooling roller and the second cooling roller are both 20 - 30 °C.

[0023] Furthermore, the film output speed of the winding film is 300 - 500 m / min, and the rotation speed ratio of the forming roller, the cooling roller, the traction roller, and the winding roller is set to 1:(1 - 1.1):(1 - 1.2):(0.8 - 1.0).

[0024] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0025] The embodiment of the present invention provides a winding film. The present invention selects an appropriate ratio of ultra - low - density polyethylene and ultra - high - molecular - weight polyethylene as the polyethylene base material system, and at the same time introduces freeze - thaw cycles and pulsed electron beam irradiation to jointly modify the polyethylene base material system and uses fluorinated graphene as a filler, realizing the dual improvement of the thinning and mechanical properties of the winding film, effectively solving the contradiction between the thinning and performance improvement of the winding film, and making up for the deficiencies of the prior art. Specifically:

[0026] 1. Selection of raw materials for the polyethylene base material system

[0027] Ultra - low - density polyethylene (ULDPE) has excellent flexibility and processability, which helps to reduce the thickness of the winding film without sacrificing its ductility; at the same time, ultra - high - molecular - weight polyethylene (UHMWPE) is known for its extremely high molecular weight and chain strength, and can significantly improve the mechanical properties of the winding film such as tensile strength, making up for the decline in mechanical properties caused by thinning. The two are mixed in an appropriate ratio, achieving a balance between flexibility and mechanical properties, and laying a foundation for the dual improvement of the thinning and mechanical properties of the winding film.

[0028] 2. Joint modification of the polyethylene base material

[0029] Due to its low density and molecular chain structure, ULDPE is prone to deformation at high temperatures. At the same time, although UHMWPE has excellent mechanical properties, its extremely high molecular weight makes processing difficult. On the one hand, through the pretreatment of freeze-thaw cycles, the relaxation and rearrangement of polyethylene molecular chains are promoted, especially the entanglement between UHMWPE molecular chains is reduced, laying a foundation for subsequent pulsed electron beam irradiation treatment. On the other hand, through the deep modification of pulsed electron beam irradiation, high-energy electron beams are used to instantaneously irradiate the polyethylene base material, generating crosslinking and chain-breaking reactions, introducing crosslinking points between ULDPE molecular chains, forming a three-dimensional network structure, enhancing its thermal stability, enabling it to maintain the stability of shape and size during subsequent processing and use, strengthening the mutual synergistic effect between different polyethylene base materials and the overall performance and stability of the winding film, and also providing favorable conditions for the uniform dispersion and effective action of fluorinated graphene.

[0030] 3. Introduce fluorinated graphene as a filler

[0031] As a high-performance filler, the interaction between fluorinated graphene and the polyethylene base material not only enhances the lubricity and antistatic properties of the film, but also forms an effective reinforcing phase in the polyethylene base material through its unique two-dimensional structure, further improving the mechanical strength and thermal stability of the winding film.

[0032] In summary, through the selection of appropriate ratios of polyethylene base materials and unique combined modification technologies, the present invention realizes a significant improvement in the mechanical properties of the winding film while reducing its thickness. The synergistic effects between the components and the modification technologies together constitute the core advantages of the technical solution of the present invention, effectively solving the contradiction between the thinning of the winding film and the improvement of its performance, and providing new ideas and methods for the development of the film material field. Description of the Drawings

[0033] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a schematic flow chart of a preparation method of a winding film provided by an embodiment of the present invention. Detailed Embodiments

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0037] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0038] In a first aspect, the present invention provides a stretch film. By weight, the stretch film comprises the following raw materials:

[0039] 40 - 60 parts of a polyethylene base material, 5 - 10 parts of fluorinated graphene, 0.5 - 1.0 part of a dispersant, 1 - 5 parts of a lubricant, and 2 - 5 parts of a stabilizer;

[0040] The polyethylene base material is obtained by subjecting ultra - low - density polyethylene and ultra - high - molecular - weight polyethylene with a weight ratio of 100:(11 - 17) to freeze - thaw cycling treatment and pulsed electron beam irradiation treatment in sequence;

[0041] The density of the ultra - low - density polyethylene is 0.904 - 0.912 g / cm³;

[0042] The weight - average molecular weight of the ultra - high - molecular - weight polyethylene is 3 million - 5 million.

[0043] The embodiments of the present invention provide a stretch film. The present invention selects an appropriate ratio of ultra - low - density polyethylene and ultra - high - molecular - weight polyethylene as the polyethylene base material system, and simultaneously introduces freeze - thaw cycling and pulsed electron beam irradiation to jointly modify the polyethylene base material system and uses fluorinated graphene as a filler, achieving a dual improvement in the thinning and mechanical properties of the stretch film, effectively solving the contradiction between the thinning of the stretch film and the improvement of its performance, and making up for the deficiencies of the prior art.

[0044] Ultra - low - density polyethylene (ULDPE) in the present invention is a modified material of polyethylene (PE). Its polymerization mechanism is similar to that of LLDPE, both are linear structures without long - chain branches, so it is also called the second - generation LLDPE. In some specific embodiments, the ultra - low - density polyethylene can be self - made according to the existing publicly disclosed preparation process or can directly use products such as the product model ATTANE of The Dow Chemical Company in the United States TM 4203 (density of 0.905 g / cm³), ATTANETM 4404G (with a density of 0.904 g / cm³), ATTANE TM Commercially available products such as 4201G (with a density of 0.912 g / cm³), preferably the product model ATTANE from The Dow Chemical Company TM 4203 (with a density of 0.905 g / cm³).

[0045] In the present invention, ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic engineering plastic with excellent comprehensive properties. Its molecular weight is usually above 1 million, and can even reach several million, but its molding processability is poor, thus limiting its wide use. This ultra-high molecular weight polyethylene can be self-made according to the existing publicly disclosed preparation process or can directly adopt commercially available products such as the product model UHMWPEU050 (weight average molecular weight of 5 million), product model UHMWPEU050 H (weight average molecular weight of 3.7 million) from Korea Yuhwa Co., Ltd. and the product model 9300CG (weight average molecular weight of 3 million) from Beijing Zhonglai Chemical Co., Ltd., preferably the product model UHMWPEU050 H from Korea Yuhwa Co., Ltd.

[0046] In the present invention, fluorinated graphene is an important new type of graphene derivative, which is a two-dimensional material formed by covalent bonding of carbon atoms of graphene with fluorine atoms. This substitution not only changes the chemical composition of graphene, but also profoundly affects its physical and chemical properties, making fluorinated graphene exhibit unique application value in many fields. This fluorinated graphene can be self-made according to the existing publicly disclosed preparation process or can directly adopt commercially available products such as those with CAS number 51311-17-2 (powder form).

[0047] In the present invention, the weight parts of the polyethylene base material can be 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, etc.

[0048] In the present invention, the weight parts of the fluorinated graphene can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0049] In the present invention, the weight parts of the dispersant can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, etc.

[0050] In the present invention, the weight parts of the lubricant can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0051] In the present invention, the weight parts of the stabilizer can be 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0052] In some specific embodiments, by weight parts, the winding film comprises the following raw materials:

[0053] 52 parts of polyethylene base material, 7 parts of fluorinated graphene, 0.8 part of dispersant, 2 parts of lubricant and 3.5 parts of stabilizer.

[0054] In some specific embodiments, the weight ratio of the ultra-low density polyethylene to the ultra-high molecular weight polyethylene is 100:14.5.

[0055] In some specific embodiments, the working condition parameters of the freeze-thaw cycle treatment include: the freezing temperature is -35~-20°C, the freezing time is 60~120 minutes; the thawing temperature is 35~45°C, the thawing time is 60~120 minutes; the number of cycle treatments is 3~6 times.

[0056] In some specific embodiments, the working condition parameters of the pulsed electron beam irradiation treatment include: the electron beam energy density is 15~40 J / cm, the electron energy is 10 kev, the number of pulses is 3~5 times, the pulse time is 50~90 μs, and the frequency is 0.2~0.6 Hz.

[0057] In some specific embodiments, the dispersant includes at least one of polyvinylpyrrolidone and polyethylene wax, the lubricant includes at least one of ethylene bisstearamide and pentaerythritol stearamide, and the stabilizer includes at least one of dibutyltin dilaurate and octyltin maleate.

[0058] In some specific embodiments, the thickness of the winding film is ≤10 μm, preferably 5~10 μm.

[0059] In a second aspect, the present invention provides a preparation method of the winding film according to any one of the first aspect, as Figure 1 shown, the preparation method comprises the following steps:

[0060] Mix the raw materials in proportion, and then add them into a screw extruder for melt blending to obtain a melt;

[0061] Feed the melt into an extrusion die for coextrusion, and then sequentially cool and solidify it through a forming roller and a cooling roller, and wind and roll it through a traction roller and a winding roller to obtain the winding film.

[0062] The preparation method of the winding film provided by the present invention is simple in operation, does not require additional specific equipment, and is suitable for industrial mass production. At the same time, this preparation method is realized based on the winding film described in any item of the first aspect, so it has at least the beneficial effects of the winding film described in any item of the first aspect, which will not be elaborated here one by one.

[0063] In some specific embodiments, the heating temperature of the screw extruder is divided into 8 zones: the temperature of zone I is 275 - 285 °C, the temperature of zone II is 250 - 265 °C, the temperature of zone III is 210 - 220 °C, the temperature of zone IV is 220 - 235 °C, the temperature of zone V is 230 - 245 °C, the temperature of zone VI is 245 - 260 °C, the temperature of zone VII is 260 - 275 °C, and the temperature of zone VIII is 275 - 285 °C; the cooling roller includes a first cooling roller and a second cooling roller, and the temperatures of the first cooling roller and the second cooling roller are both 20 - 30 °C.

[0064] In some specific embodiments, the film output speed of the winding film is 300 - 500 m / min, and the rotation speed ratio of the forming roller, the cooling roller, the traction roller, and the winding roller is set to 1:(1 - 1.1):(1 - 1.2):(0.8 - 1.0).

[0065] It should be noted that for the raw material components involved in the winding film and its preparation method provided in the embodiments of the present invention, if there is no special limitation or specific description, commercially available products can be directly purchased or prepared by oneself according to the existing preparation methods; at the same time, for the operation steps involved in the preparation method, if there is no special limitation or specific description, they can be carried out according to the existing winding film preparation method or directly using commercially available equipment, which will not be elaborated in this invention document one by one.

[0066] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0067] Example 1: This example provides a winding film, which includes the following raw materials in parts by weight:

[0068] 52 parts of polyethylene base material, 7 parts of fluorinated graphene, 0.8 part of dispersant, 2 parts of lubricant, and 3.5 parts of stabilizer;

[0069] The polyethylene base material is obtained by mixing ultra-low density polyethylene and ultra-high molecular weight polyethylene in a weight ratio of 100:14.5, and then sequentially subjected to freeze-thaw cycle treatment and pulse electron beam irradiation treatment; wherein the working condition parameters of the freeze-thaw cycle treatment include: a freezing temperature of -30°C, a freezing time of 90 minutes; a thawing temperature of 40°C, a thawing time of 90 minutes; and a number of cycle treatments of 5 times; and the working condition parameters of the pulse electron beam irradiation treatment include: an electron beam energy density of 25 J / cm, an electron energy of 10 kev, a pulse number of 4 times, a pulse time of 80 μs, and a frequency of 0.5 Hz;

[0070] The density of the ultra-low density polyethylene is 0.905 g / cm³;

[0071] The weight average molecular weight of the ultra-high molecular weight polyethylene is 3.7 million;

[0072] The dispersant is polyethylene wax;

[0073] The lubricant is ethylene bis stearamide;

[0074] The stabilizer is octyltin maleate.

[0075] The preparation method of the stretch film comprises the following steps:

[0076] The raw materials are mixed in proportion, and then added into a screw extruder for melt blending to obtain a melt;

[0077] The melt is fed into an extrusion die for co-extrusion, and then cooled and solidified by a forming roller and a cooling roller, and is pulled and wound by a pulling roller and a winding roller to obtain the stretch film;

[0078] Among them, the heating temperature of the screw extruder is divided into 8 sections: the temperature of zone I is 280°C, the temperature of zone II is 260°C, the temperature of zone III is 215°C, the temperature of zone IV is 230°C, the temperature of zone V is 240°C, the temperature of zone VI is 250°C, the temperature of zone VII is 270°C, and the temperature of zone VIII is 280°C; the cooling roller includes a first cooling roller and a second cooling roller, and the temperatures of the first cooling roller and the second cooling roller are both 25°C; the film discharge speed of the wrapping film is 400m / min, and the speed ratio of the forming roller, the cooling roller, the traction roller and the winding roller is set to 1:1.05:1.18:0.9.

[0079] Example 2: This example provides a stretch film, which includes the following raw materials in parts by weight:

[0080] 40 parts of polyethylene base material, 5 parts of fluorinated graphene, 0.5 parts of dispersant, 1 part of lubricant and 2 parts of stabilizer;

[0081] The polyethylene base material is obtained by mixing ultra-low density polyethylene and ultra-high molecular weight polyethylene with a weight ratio of 100:11, and then successively performing freeze-thaw cycle treatment and pulsed electron beam irradiation treatment; wherein, the working condition parameters of the freeze-thaw cycle treatment include: the freezing temperature is -35°C, the freezing time is 60 minutes; the thawing temperature is 45°C, the thawing time is 60 minutes; the number of cycle treatments is 6 times; the working condition parameters of the pulsed electron beam irradiation treatment include: the electron beam energy density is 15 J / cm, the electron energy is 10 kev, the number of pulses is 5 times, the pulse time is 50 μs, and the frequency is 0.2 Hz;

[0082] The density of the ultra-low density polyethylene is 0.904 g / cm³;

[0083] The weight-average molecular weight of the ultra-high molecular weight polyethylene is 5 million;

[0084] The dispersant is polyvinylpyrrolidone;

[0085] The lubricant is pentaerythritol stearamide;

[0086] The stabilizer is dibutyltin dilaurate.

[0087] The preparation method of the above-mentioned stretch film is the same as that of Example 1.

[0088] Example 3: This example provides a stretch film. By weight, the stretch film includes the following raw materials:

[0089] 60 parts of polyethylene base material, 10 parts of fluorinated graphene, 1.0 part of dispersant, 5 parts of lubricant, and 5 parts of stabilizer;

[0090] The polyethylene base material is obtained by mixing ultra-low density polyethylene and ultra-high molecular weight polyethylene with a weight ratio of 100:17, and then successively performing freeze-thaw cycle treatment and pulsed electron beam irradiation treatment; wherein, the working condition parameters of the freeze-thaw cycle treatment include: the freezing temperature is -20°C, the freezing time is 120 minutes; the thawing temperature is 35°C, the thawing time is 120 minutes; the number of cycle treatments is 3 times; the working condition parameters of the pulsed electron beam irradiation treatment include: the electron beam energy density is 40 J / cm, the electron energy is 10 kev, the number of pulses is 3 times, the pulse time is 90 μs, and the frequency is 0.6 Hz;

[0091] The density of the ultra-low density polyethylene is 0.912 g / cm³;

[0092] The weight-average molecular weight of the ultra-high molecular weight polyethylene is 3 million;

[0093] The dispersant is polyethylene wax;

[0094] The lubricant is pentaerythritol stearamide;

[0095] The stabilizer is dibutyltin dilaurate.

[0096] The preparation method of the above-mentioned winding film is the same as that of Example 1.

[0097] Comparative Example 1: This example provides a winding film and its preparation method. The difference from Example 1 is only that: the weight ratio of the ultra-low density polyethylene and the ultra-high molecular weight polyethylene is 87.5:27 (that is, the weight ratio of the ultra-low density polyethylene and the ultra-high molecular weight polyethylene is different); the remaining steps and parameters are the same.

[0098] Comparative Example 2: This example provides a winding film and its preparation method. The difference from Example 1 is only that: the polyethylene base material is obtained by mixing ultra-low density polyethylene and ultra-high molecular weight polyethylene with a weight ratio of 100:14.5, and then successively performing pulsed electron beam irradiation treatment and freeze-thaw cycle treatment (that is, the sequence of pulsed electron beam irradiation treatment and freeze-thaw cycle treatment is different); the remaining steps and parameters are the same.

[0099] Test Example

[0100] In this example, the winding films provided in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to performance evaluation tests according to the test methods disclosed in the prior art. The specific test results are shown in Table 1; among them, the test standards for each item are as follows: 1) The thickness test was carried out with reference to GB / T6672-2001 Plastics - Films and Sheets - Determination of Thickness by Mechanical Measurement; 2) The tensile strength test was carried out with reference to GB / T 1040-2006 Plastics - Determination of Tensile Properties.

[0101] Table 1

[0102] Test sample Thickness (μm) Tensile strength (Mpa) Example 1 5 46.1 Example 2 5 40.8 Example 3 5 42.4 Comparative example 1 5 27.9 Comparative example 2 5 30.5

[0103] As can be seen from Table 1, compared with Comparative Examples 1 to 2, the winding film provided in the embodiment of the present invention still maintains a tensile strength of more than 40 Mpa on the premise that the thickness is only 5 μm, achieving a double improvement in the thinning and mechanical properties of the winding film, effectively solving the contradiction between the thinning and performance improvement of the winding film, and providing new ideas and methods for the development of the film material field.

[0104] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any recited number (fractional or integer) within the indicated range.

[0105] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A stretch film, characterized in that, in parts by weight, the stretch film comprises the following raw materials: 52 parts of polyethylene base material, 7 parts of fluorinated graphene, 0.8 parts of dispersant, 2 parts of lubricant and 3.5 parts of stabilizer; The polyethylene base material is obtained by mixing ultra-low density polyethylene and ultra-high molecular weight polyethylene in a weight ratio of 100:14.5, and then sequentially subjected to freeze-thaw cycle treatment and pulse electron beam irradiation treatment; wherein the working condition parameters of the freeze-thaw cycle treatment include: a freezing temperature of -30°C, a freezing time of 90 minutes; a thawing temperature of 40°C, a thawing time of 90 minutes; and a number of cycle treatments of 5 times; and the working condition parameters of the pulse electron beam irradiation treatment include: an electron beam energy density of 25 J / cm, an electron energy of 10 kev, a pulse number of 4 times, a pulse time of 80 μs, and a frequency of 0.5 Hz; The density of the ultra-low density polyethylene is 0.905 g / cm³; The weight average molecular weight of the ultra-high molecular weight polyethylene is 3.7 million; The dispersant is polyethylene wax; The lubricant is ethylene bis stearamide; The stabilizer is octyltin maleate; The preparation method of the stretch film comprises the following steps: The raw materials are mixed in proportion, and then added into a screw extruder for melt blending to obtain a melt; The melt is fed into an extrusion die for co-extrusion, and then cooled and solidified by a forming roller and a cooling roller, and is pulled and wound by a pulling roller and a winding roller to obtain the stretch film; The heating temperature of the screw extruder is divided into 8 sections: the temperature of zone I is 280°C, the temperature of zone II is 260°C, the temperature of zone III is 215°C, the temperature of zone IV is 230°C, the temperature of zone V is 240°C, the temperature of zone VI is 250°C, the temperature of zone VII is 270°C, and the temperature of zone VIII is 280°C; the cooling roller includes a first cooling roller and a second cooling roller, and the temperatures of the first cooling roller and the second cooling roller are both 25°C; the film discharge speed of the wrapping film is 400m / min, and the speed ratio of the forming roller, the cooling roller, the traction roller and the winding roller is set to 1: 1.05:1.18:0.9。

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