An ultra-low weight, high-performance fruit peel textured PE film and its preparation method

Abstract

This invention discloses an ultra-low weight, high-performance fruit peel textured PE film, comprising an upper film layer, an intermediate film layer, and a lower film layer distributed sequentially from top to bottom. The upper and lower film layers are both obtained by melt extrusion of a first mixture using a twin-screw extruder, and the intermediate film layer is obtained by melt extrusion of a second mixture using a twin-screw extruder. The weight of the PE film is 11–15 g / m³. 2 The PE film has a fruit peel texture structure. By weight, the first mixture comprises 25-35 parts LDPE resin, 65-75 parts HDPE resin, and 5-8 parts slip agent; by weight, the second mixture comprises 85-95 parts mLLDPE resin. This invention proposes an ultra-low weight, high-performance fruit peel texture PE film with a weight as low as 11 g / m³. 2 It has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60. It is low-weight and high-performance, overcoming the shortcomings of existing technologies.

Description

Technical Field

[0001] This invention relates to the field of PE film, and more particularly to an ultra-low weight, high-performance fruit peel textured PE film and its preparation method. Background Technology

[0002] Polyethylene film (PE film) is a thin film produced by extrusion blow molding, extrusion calendering, or extrusion casting of high-density polyethylene (HDPE resin), low-density polyethylene (LDPE resin), and various additives. Due to its characteristics such as impermeability, pollution prevention, softness and comfort, and safety and non-toxicity, it is used not only as food packaging film, pharmaceutical packaging film, pool film, waterproof film, and agricultural film, but also as a base film in various hygiene products such as sanitary napkins, baby diapers, and adult incontinence products.

[0003] With the continuous advancement of hygiene product technology and the increasing demands of consumers, hygiene products are gradually evolving towards being "softer, more comfortable, and thinner," placing higher requirements on PE film, one of the raw materials for hygiene products. Traditionally, the weight of PE film is around 24g / m³. 2 The above-mentioned PE films cannot meet market demand.

[0004] To overcome the shortcomings of traditional PE film products, major PE film manufacturers have been developing and manufacturing lightweight PE films to meet market demand. However, as the weight of PE film decreases, the product's performance, such as tensile strength and elongation at break, also declines, failing to meet the product's usage requirements. This means that the lightweight, high-performance PE films used in these products still mainly rely on imports, which to some extent increases the production cost of high-quality hygiene products. Summary of the Invention

[0005] One of the objectives of this invention is to provide an ultra-low weight, high-performance fruit peel textured PE film, with a weight as low as 11 g / m³. 2 It has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60. It is low-weight and high-performance, overcoming the shortcomings of existing technologies.

[0006] The second objective of this invention is to provide a method for preparing an ultra-low weight, high-performance fruit peel textured PE film. The method is simple, easy to operate, and ensures that the obtained PE film has low weight and high performance, while also having a low coefficient of friction to meet the product's usage requirements.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] An ultra-low weight, high-performance fruit peel textured PE film comprises an upper film layer, an intermediate film layer, and a lower film layer distributed sequentially from top to bottom. The upper and lower film layers are both obtained by melt extrusion of a first mixture using a twin-screw extruder, and the intermediate film layer is obtained by melt extrusion of a second mixture using a twin-screw extruder. The weight of the PE film is 11–15 g / m³. 2 Furthermore, the PE film has a fruit peel texture structure;

[0009] According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin and 5-8 parts of slip agent;

[0010] The second mixture comprises 85 to 95 parts of mLLDPE resin, calculated by mass.

[0011] Furthermore, both the first mixture and the second mixture further include color masterbatch;

[0012] According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin, 5-8 parts of slip agent and 5-10 parts of color masterbatch;

[0013] The second mixture comprises 85-95 parts of mLLDPE resin and 5-15 parts of color masterbatch, calculated by mass.

[0014] Furthermore, the first mixture comprises 35 parts of LDPE resin, 65 parts of HDPE resin, 8 parts of slip agent, and 5 parts of color masterbatch;

[0015] The second mixture comprises 90 parts of mLLDPE resin and 10 parts of color masterbatch.

[0016] Furthermore, the weight of the upper film layer is 2.5–3.5 g / m³. 2 The weight of the intermediate film layer is 6-8 g / m³. 2 The weight of the lower film layer is 2.5–3.5 g / m³. 2 .

[0017] Furthermore, the slip agent includes at least one of oleamide and erucamide.

[0018] Furthermore, the color masterbatch includes either black PE masterbatch or white PE masterbatch.

[0019] A method for preparing an ultra-low weight, high-performance fruit peel textured PE film, comprising the following steps:

[0020] S1. HDPE resin, LDPE resin, color masterbatch and slip agent are mixed evenly according to the formula to obtain the first mixture; LDPE resin and color masterbatch are mixed evenly according to the formula to obtain the second mixture.

[0021] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 25-30 r / min for melting, and then conveyed to the first and third flow channels of the die cavity while maintaining the temperature. The second mixture is added to the screw of a twin-screw extruder at a speed of 35-40 r / min for melting, and then conveyed to the second flow channel of the die cavity while maintaining the temperature. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film through the casting steel roller and the casting pressure roller.

[0022] S3. After embossing, matte finishing and cooling the intermediate film material, the surface of the intermediate film material is then corona treated, and after winding, an ultra-low weight, high-performance fruit peel textured PE film is obtained.

[0023] Further, in step S3, the temperature of the casting steel roll and the casting pressure roll is 20-28°C, and the mutual clamping force between the casting steel roll and the casting pressure roll is 4-6 kg / cm². 2 .

[0024] Furthermore, in step S3, the corona current in the corona treatment step is 3 to 5 A.

[0025] Furthermore, in step S3, the ultra-low weight high-performance fruit peel textured PE film has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60.

[0026] The technical solutions provided in this application embodiment may include the following beneficial effects:

[0027] 1. By combining the fruit peel texture structure of the PE film with the innovative formulation of the first and second mixtures, the resulting PE film not only has an ultra-low weight, reducing the use of raw materials and lowering production costs, but also has a low coefficient of friction, high tensile strength, high elongation at break, and good heat-sealing performance, meeting the high-performance requirements of subsequent processing applications of PE film.

[0028] 2. In order to achieve a low coefficient of friction in the PE film without compromising performance, the PE film in this technical solution has a fruit peel texture. The fruit peel texture can increase the roughness of the PE film surface, thereby reducing the low coefficient of friction of the PE film surface. At the same time, the fruit peel texture can also reduce the contact area between PE films, further reducing the possibility of mutual adhesion between PE films. Moreover, since the fruit peel texture is an irregular texture structure, it will not cause a decrease in the performance of the PE film, thus ensuring the performance of the PE film and improving the problem of decreased performance such as tensile strength and elongation at break of PE film caused by using a grid texture.

[0029] 3. The first mixture of PE resin is composed of two types of PE resin: LDPE resin and HDPE resin. The second mixture uses only mLLDPE resin as the PE resin. The three commonly used PE resins are divided into two systems. The high crystallinity, high strength and good toughness of mLLDPE resin are fully utilized, thereby giving the second mixture higher tensile strength and higher elongation at break. This results in the intermediate film layer having higher tensile strength and higher elongation at break, thus significantly improving the performance of the PE film. Attached Figure Description

[0030] Figure 1 This is an image of the PE film obtained in Example 1 of the preparation method of an ultra-low weight, high performance fruit peel textured PE film of the present invention.

[0031] Figure 2 This is an image of the PE film obtained in Comparative Example 1 in the preparation method of an ultra-low weight, high-performance fruit peel textured PE film of the present invention. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] This technical solution provides an ultra-low weight, high-performance fruit peel textured PE film, comprising an upper film layer, an intermediate film layer, and a lower film layer distributed sequentially from top to bottom. The upper and lower film layers are both obtained by melt extrusion of a first mixture using a twin-screw extruder, and the intermediate film layer is obtained by melt extrusion of a second mixture using a twin-screw extruder. The weight of the PE film is 11–15 g / m³. 2 Furthermore, the PE film has a fruit peel texture structure;

[0034] According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin and 5-8 parts of slip agent;

[0035] The second mixture comprises 85 to 95 parts of mLLDPE resin, calculated by mass.

[0036] To achieve low weight and high performance in PE (polyethylene) film, along with a low coefficient of friction, this technical solution proposes an ultra-low weight, high performance fruit-peel textured PE film. This film comprises an upper film layer, an intermediate film layer, and a lower film layer distributed sequentially from top to bottom. Through the innovative combination of the fruit-peel textured structure of the PE film and the formulations of the first and second mixtures, the resulting PE film not only possesses ultra-low weight, reducing raw material usage and lowering production costs, but also exhibits a low coefficient of friction, high tensile strength, high elongation at break, and excellent heat-sealing performance, meeting the high-performance requirements for subsequent processing and applications of the PE film.

[0037] Specifically, due to the high coefficient of friction on the surface of PE film, there is a problem of mutual adhesion, which brings considerable inconvenience to subsequent production and processing of PE film. In order to overcome the above defects and reduce the coefficient of friction on the surface of PE film, existing technologies often increase the amount of slip agent added during processing. However, when the basis weight of PE film is low, the three-dimensional thickness of PE film is also reduced accordingly, making it difficult for users to install PE film on the machine and resulting in a poor user experience. Therefore, the PE film design in this solution cannot be based on the above principles.

[0038] To address the aforementioned issues, existing technologies employ PE films with a mesh pattern. This mesh pattern increases the surface roughness of the PE film, mitigating the high coefficient of friction. However, achieving this reduction in surface friction is contradictory to achieving high performance. This is because the tensile strength and elongation at break are lower at the junctions of the mesh lines compared to other areas, making them prone to tearing. This leads to a decrease in the overall tensile strength and elongation at break of the PE film, and the more mesh lines there are, the greater the performance degradation. Therefore, the PE film texture design in this solution cannot be based on the aforementioned principles.

[0039] To achieve a low coefficient of friction in the PE film without compromising performance, this technical solution incorporates a fruit peel texture in the PE film. This texture increases the surface roughness of the PE film, thereby reducing the coefficient of friction. Simultaneously, the texture reduces the contact area between PE films, further decreasing the likelihood of adhesion. Furthermore, because the texture is irregular, it does not degrade the PE film's performance, ensuring its integrity and mitigating the performance degradation issues associated with using a mesh texture, such as reduced tensile strength and elongation at break.

[0040] It should be noted that the fruit peel texture can be either pear-like or lychee-like; there is no specific limitation here.

[0041] In existing technologies, PE films used in hygiene products, whether single-layer or three-layer, use the same PE resin raw materials for each layer. These PE resin raw materials are generally composed of three common resins: LDPE (low-density polyethylene), HDPE (high-density polyethylene), and mLLDPE (metallocene linear low-density polyethylene). The complementary properties of these three different types of PE resins are utilized to obtain a PE film that meets the application requirements. However, precisely because of this complementary nature, the individual advantages of each type of PE resin are neutralized and cannot be fully realized. This necessitates a high weight for the PE film to achieve high performance and meet application requirements. When the weight of the PE film decreases, the product's properties, such as tensile strength and elongation at break, also decrease, making it impossible to simultaneously achieve both low weight and high performance.

[0042] In this technical solution, the first mixture of PE resin (polyethylene resin) is composed of two types of PE resin: LDPE resin and HDPE resin. The second mixture uses only mLLDPE resin as the PE resin. The three commonly used PE resins are divided into two systems. The high crystallinity, high strength and good toughness of mLLDPE resin are fully utilized, thereby giving the second mixture higher tensile strength and higher elongation at break. This results in the intermediate film layer having higher tensile strength and higher elongation at break, thus significantly improving the performance of the PE film.

[0043] Since the performance of PE film is crucial to its application, if only the second mixture is used to prepare a single-layer PE film, although the tensile strength and elongation at break of the PE film are improved, these properties are still limited and cannot meet the extremely high requirements for tensile strength and elongation at break. Therefore, this technical solution uses the first and second mixtures in combination, fully utilizing the tensile strength, processing performance, and heat-sealing performance of the first mixture, and combining it with the higher tensile strength and elongation at break performance of the second mixture. This results in a PE film with high tensile strength, high elongation at break, and excellent subsequent processing performance, meeting the requirements for low weight and high performance. In addition, since mLLDPE resin is relatively expensive, using mLLDPE resin as the PE resin in both the first and second mixtures will lead to a high cost of PE film. However, this technical solution uses LDPE resin and HDPE resin as the PE resin in the second mixture, which not only ensures that the obtained PE film has low weight and high performance, but also reduces its cost and improves its cost-effectiveness.

[0044] Specifically, the first mixture of raw materials includes LDPE resin, HDPE resin and slip agent, wherein the crystallinity of HDPE resin is 80% to 90%, and high crystallinity means high tensile strength, thus giving HDPE resin high tensile strength.

[0045] Secondly, LDPE resin has a crystallinity of 55%–65%, which is significantly lower than that of HDPE resin. Therefore, it exhibits better flexibility and higher elongation, compensating for the drawback of HDPE resin, which, due to its higher crystallinity, has stronger intermolecular forces, requiring higher temperatures to melt and resulting in poorer processing performance of the first mixture. Furthermore, since the melt flow rate of the raw materials directly affects the heat-sealing performance of the PE film, and LDPE resin has a high melt flow rate and good fluidity, adding LDPE resin to the first mixture formulation imparts better heat-sealing properties.

[0046] Since the properties of the upper and lower film layers have a significant impact on the performance of the PE film, this technical solution uses a mixture of LDPE and HDPE resins as the first mixture. This fully utilizes the properties of both LDPE and HDPE resins. Without adding mL of LDPE resin to the first mixture, it achieves relatively good tensile strength, processing performance, and heat-sealing performance. This results in upper and lower film layers with relatively good tensile strength, processing performance, and heat-sealing performance, which, in conjunction with the intermediate film layer, meet the extremely high performance requirements of the PE film in subsequent processing applications.

[0047] Furthermore, the raw materials of the first mixture in this technical solution also include a slip agent. Adding a slip agent to the first mixture formula, in combination with the fruit peel texture, can utilize both the slip agent's characteristic of reducing the coefficient of friction and the fruit peel texture's characteristic of reducing the coefficient of friction, resulting in a lower coefficient of friction on the PE film surface, thereby ensuring good subsequent processing properties and packaging efficiency of the PE film.

[0048] Furthermore, according to the mass fractions, the first mixture in this technical solution includes 35-45 parts of LDPE resin, 65-75 parts of HDPE resin, and 5-8 parts of slip agent. The addition amounts of LDPE resin and HDPE resin are coordinated to give the upper and lower film layers excellent tensile strength, processing performance, and heat-sealing performance. The slip agent mainly serves to reduce the coefficient of friction. Only a small amount needs to be added, and in combination with the fruit peel texture, it can make the PE film surface have a low coefficient of friction.

[0049] To further explain, both the first mixture and the second mixture also include color masterbatch;

[0050] According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin, 5-8 parts of slip agent and 5-10 parts of color masterbatch;

[0051] The second mixture comprises 85-95 parts of mLLDPE resin and 5-15 parts of color masterbatch, calculated by mass.

[0052] In a preferred embodiment of this technical solution, both the first mixture and the second mixture further include color masterbatch. Adding color masterbatch to the formulations of the first mixture and the second mixture can impart a certain color to the PE film, thereby meeting market demands.

[0053] Furthermore, calculated by mass parts, the second mixture in this technical solution includes 85-95 parts of mLLDPE resin and 5-15 parts of color masterbatch. mLLDPE resin has a significant impact on the performance of the intermediate thin layer. If its addition amount is less than 85 parts, the performance of the intermediate thin layer will decrease, failing to meet the requirements for low-weight, high-performance PE film. If its addition amount is greater than 95 parts, the performance improvement of the intermediate film layer is not significant, and it increases costs. Therefore, in order to achieve both high performance and high cost-effectiveness in the PE film, this technical solution limits the addition amount of mLLDPE resin in the second mixture to 85-95 parts.

[0054] To further explain, the first mixture comprises 35 parts of LDPE resin, 65 parts of HDPE resin, 8 parts of slip agent, and 5 parts of color masterbatch;

[0055] The second mixture comprises 90 parts of mLLDPE resin and 10 parts of color masterbatch.

[0056] In a preferred embodiment of this technical solution, by optimizing the addition amounts of the first and second mixtures, the PE film can achieve better performance for the same weight, while controlling its cost, which is beneficial to improving the cost-effectiveness of the PE film.

[0057] To further clarify, the weight of the upper film layer is 2.5–3.5 g / m². 2 The weight of the intermediate film layer is 6-8 g / m³. 2 The weight of the lower film layer is 2.5–3.5 g / m³. 2 .

[0058] In a preferred embodiment of this technical solution, since the intermediate film layer has a significant impact on the PE film, its weight is limited to 6-8 g / m³. 2 This further ensures the performance of the PE film.

[0059] Furthermore, the weight of both the upper and lower membrane layers is limited to 2.5–3.5 g / m³. 2 This simplifies the production process and, when combined with the weight of the intermediate film layer, further enhances the performance of the PE film.

[0060] Preferably, the weight of the upper film layer is 3.5 g / m³. 2 The weight of the intermediate film layer is 8.0 g / m³. 2 The weight of the lower membrane layer is 3.5 g / m. 2 .

[0061] To further explain, the slip agent includes at least one of oleamide and erucamide.

[0062] In a preferred embodiment of this technical solution, the slip agent includes either oleamide or erucamide. Since both oleamide and erucamide contain polar groups such as hydroxyl and amide groups, their compatibility with PE is poor. When added to the formulation, they will migrate to the surface of the film after processing, and then solidify and crystallize to form a smooth surface, thereby reducing the coefficient of friction of the PE film.

[0063] Preferably, the slip agent includes oleamide and erucamide.

[0064] Furthermore, the migration rate of oleamide and erucamide to the surface is affected by their molecular weight and crystallinity. The larger the molecular weight, the better the compatibility with other resin raw materials in the formulation, and the slower the migration rate; conversely, the smaller the molecular weight, the worse the compatibility with other resin raw materials in the formulation, and the faster the migration rate. In addition, compared with oleamide, erucamide has better thermal stability, stronger antioxidant properties, and generates fewer volatiles during processing. Moreover, once it completes its migration from the interior of the film to the film surface, its performance in reducing the coefficient of friction is superior to that of oleamide.

[0065] Therefore, this technical solution uses a combination of oleamide and erucamide. Oleamide has a relatively small molecular weight and a fast migration rate, which gives the PE film a low coefficient of friction in its initial state. By utilizing the superior performance of reducing the coefficient of friction, it helps to ensure that the PE film always has a low coefficient of friction. Furthermore, erucamide has good thermal stability and strong antioxidant properties, which avoids the occurrence of partial failure of the slip agent due to oxidation during processing.

[0066] To further clarify, the color masterbatch includes either black PE masterbatch or white PE masterbatch.

[0067] In the prior art, white PE film and black PE film have the greatest market demand. Therefore, in a preferred embodiment of this technical solution, the color masterbatch preferably includes either black PE masterbatch or white PE masterbatch to meet actual market demand.

[0068] A method for preparing an ultra-low weight, high-performance fruit peel textured PE film, comprising the following steps:

[0069] S1. HDPE resin, LDPE resin, color masterbatch and slip agent are mixed evenly according to the formula to obtain the first mixture; LDPE resin and color masterbatch are mixed evenly according to the formula to obtain the second mixture.

[0070] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 25-30 r / min for melting, and then conveyed to the first and third flow channels of the die cavity while maintaining the temperature. The second mixture is added to the screw of a twin-screw extruder at a speed of 35-40 r / min for melting, and then conveyed to the second flow channel of the die cavity while maintaining the temperature. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film through the casting steel roller and the casting pressure roller.

[0071] S3. After embossing, matte finishing and cooling the intermediate film material, the surface of the intermediate film material is then corona treated, and after winding, an ultra-low weight, high-performance fruit peel textured PE film is obtained.

[0072] This technical solution also proposes a method for preparing an ultra-low weight, high-performance fruit peel textured PE film, including the following steps:

[0073] S1. HDPE resin, LDPE resin, color masterbatch and slip agent are mixed evenly according to the formula to obtain the first mixture. mLLDPE resin and color masterbatch are mixed evenly according to the formula to obtain the second mixture. The raw material mixing method is simple and avoids the impact of uneven raw material mixing on the performance of PE film.

[0074] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 25-30 r / min for melting and then conveyed at a constant temperature to the first and third flow channels of the die cavity. The second mixture is added to the screw of a twin-screw extruder at a speed of 35-40 r / min for melting and then conveyed at a constant temperature to the second flow channel of the die cavity. The melts in the first, second, and third flow channels converge at the die lip and undergo three-layer co-extrusion. The intermediate film is formed by pressing the melts with the casting steel rollers and casting pressure rollers. The process is simple and easy to operate. The design of the multi-channel composite die ensures that the melts in each channel are evenly distributed after spreading at the die lip and prevents material cross-contamination between channels. This results in high processing precision and ensures product performance. In addition, by designing the speed of the two screws, the extrusion volume of the two screws is controlled to ensure balanced extrusion of the first and second mixtures, enabling the overall formulation design to be realized and further ensuring that the PE film has a low coefficient of friction, low weight, and high performance.

[0075] S3. After embossing, matte finishing and cooling stabilization of the intermediate film material, the surface of the intermediate film material is then subjected to corona treatment to give the PE film surface a lower coefficient of friction. The fruit peel texture on the surface of the PE film can reduce the contact area between PE films, further preventing the adhesion between PE films and improving the subsequent processing performance of the PE film.

[0076] Preferably, in step S1, the mixing weight of the first mixture and the second mixture is ≤10Kg, and the mixing time is 0.8 to 1min, to further ensure uniform mixing and thus ensure the performance of each membrane layer.

[0077] Preferably, in step S2, the melting temperature of the twin-screw extruder is 200-210°C, the holding temperature is 210-230°C, and the die temperature is 230-250°C. This allows the temperature of the twin-screw extruder to gradually increase from the melting point to the die temperature, which helps to ensure the fluidity of the first and second mixtures in the twin-screw extrusion and ensures that the first and second mixtures can be co-extruded in three layers after melting.

[0078] To further explain, in step S3, the temperature of the casting steel roller and the casting pressure roller is 20–28°C, and the mutual clamping force between the casting steel roller and the casting pressure roller is 4–6 kg / cm². 2 .

[0079] During the cooling and shaping process, the temperature of the cooling water is 25℃. When the temperature between the casting steel roller and the casting pressure roller is less than 20℃, the temperature is too low, and the cooling water is prone to condense on the intermediate film material, affecting the subsequent processing of the intermediate film material. When the temperature between the casting steel roller and the casting pressure roller is greater than 28℃, the temperature is too high, causing the intermediate film material to be brittle and difficult to shape.

[0080] Furthermore, the mutual clamping force between the casting steel roll and the casting pressure roll is 4–6 kg / cm. 2 This ensures that each layer of the membrane is compressed and formed.

[0081] To further explain, in step S3, the corona current in the corona treatment step is 3 to 5 A.

[0082] Since sanitary products consist of a top layer, an absorbent core, and a bottom film, and the PE film serves as the bottom film, it needs to be bonded to the top layer to enclose the absorbent core between the top layer and the bottom film. Therefore, this technical solution limits the corona current of the corona treatment to 3-5A, so that the surface tension of the PE film reaches 36-42mN / m, which facilitates the adhesion between the PE film as the bottom film and the top layer of the sanitary product, ensuring the performance of the PE film.

[0083] To further explain, in step S3, the ultra-low weight high-performance fruit peel textured PE film has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60.

[0084] The PE film produced by this technical solution has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60. It has low weight and high performance, and the low coefficient of friction meets the product's usage requirements.

[0085] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0086] Performance testing:

[0087] Weight: The weight was measured using an electronic balance;

[0088] Tensile strength: The tensile strength was determined according to the test method in GB / T 1040.3-2006 Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets.

[0089] Elongation at break: The elongation at break was determined according to the test method in GB / T 1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets.

[0090] Longitudinal constant deformation 5% tensile force: The elastic modulus was determined according to the test method in GB / T 1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets.

[0091] Surface tension: The surface tension was determined according to the test method in GB / T 14216-2008 Determination of wetting tension of plastic films and sheets.

[0092] Heat seal strength: The heat seal strength is determined according to the test method in "QB2358-1998 Test method for heat seal strength of plastic film packaging bags".

[0093] Coefficient of friction: The coefficient of friction of the PE film surface was determined according to the test method of GB / T10006-2021 Determination of Coefficient of Friction of Plastic Films and Sheets.

[0094] Example 1

[0095] S1. Mix 25 parts of LDPE resin, 75 parts of HDPE resin, 5 parts of oleamide and 5 parts of white PE masterbatch evenly to obtain a first mixture weighing 10 kg; mix 85 parts of LDPE resin and 15 parts of white PE masterbatch evenly to obtain a second mixture weighing 10 kg.

[0096] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 25 r / min for melting, and then conveyed at a constant temperature to the first and third flow channels of the die cavity. The second mixture is added to the screw of a twin-screw extruder at a speed of 35 r / min for melting, and then conveyed at a constant temperature to the second flow channel of the die cavity. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film together with the casting steel roller and the casting pressure roller. The temperature of the casting steel roller and the casting pressure roller is 20°C, and the mutual clamping force between the casting steel roller and the casting pressure roller is 4 kg / cm.2 ;

[0097] S3. After pressing the intermediate film material into a pear-like texture, applying a matte finish, and cooling it for conditioning, the surface of the intermediate film material is then subjected to corona treatment. After winding, an ultra-low weight, high-performance fruit-peel textured PE film is obtained; wherein, the corona treatment current is 3A.

[0098] Example 2

[0099] S1. Mix 30 parts of LDPE resin, 70 parts of HDPE resin, 5 parts of erucamide and 8 parts of white PE masterbatch evenly to obtain a first mixture weighing 10 kg; mix 90 parts of LDPE resin and 10 parts of white PE masterbatch evenly to obtain a second mixture weighing 10 kg.

[0100] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 28 r / min for melting, and then conveyed at a constant temperature to the first and third flow channels of the die cavity. The second mixture is added to the screw of a twin-screw extruder at a speed of 38 r / min for melting, and then conveyed at a constant temperature to the second flow channel of the die cavity. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film together with the casting steel roller and the casting pressure roller. The temperature of the casting steel roller and the casting pressure roller is 25°C, and the mutual clamping force between the casting steel roller and the casting pressure roller is 5 kg / cm. 2 ;

[0101] S3. After pressing the intermediate film material with a lychee texture, applying a matte finish, and cooling for stabilization, the surface of the intermediate film material is then subjected to corona treatment. After winding, an ultra-low weight, high-performance fruit peel textured PE film is obtained; wherein, the corona treatment current is 4A.

[0102] Example 3

[0103] S1. Mix 35 parts of LDPE resin, 65 parts of HDPE resin, 8 parts of erucamide and 5 parts of white PE masterbatch evenly to obtain a first mixture weighing 10 kg; mix 90 parts of mLLDPE resin and 10 parts of white PE masterbatch evenly to obtain a second mixture weighing 10 kg.

[0104] S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 30 r / min for melting, and then conveyed at a constant temperature to the first and third flow channels of the die cavity. The second mixture is added to the screw of a twin-screw extruder at a speed of 40 r / min for melting, and then conveyed at a constant temperature to the second flow channel of the die cavity. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film together with the casting steel roller and the casting pressure roller. The temperature of the casting steel roller and the casting pressure roller is 25°C, and the mutual clamping force between the casting steel roller and the casting pressure roller is 5 kg / cm. 2 ;

[0105] S3. After pressing the intermediate film material with a lychee texture, applying a matte finish, and cooling for stabilization, the surface of the intermediate film material is then subjected to corona treatment. After winding, an ultra-low weight, high-performance fruit peel textured PE film is obtained; wherein, the corona treatment current is 5A.

[0106] PE films were prepared using the preparation methods described in Examples 1-3 above, and the performance of the PE films was tested. The specific results are shown in Table 1 below:

[0107] Table 1 Performance test results of Examples 1-3

[0108]

[0109]

[0110] As can be seen from the performance test results of each embodiment in the table above, the PE film prepared by the method for preparing an ultra-low weight, high-performance fruit peel textured PE film has a weight as low as 11 g / m³. 2 It has a tensile strength ≥5.50N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.60. It features low weight and high performance, while also having a low coefficient of friction, which meets the product's usage requirements.

[0111] Comparing the performance of Examples 1 to 3, Example 3 has better overall performance. Therefore, based on Example 3, the present invention uses the controlled variable method to set the comparative example.

[0112] Comparative Example 1

[0113] Comparative Example 1: The preparation method, raw materials and composition of the first and second mixtures of Comparative Example 1 and Example 3 are the same. The difference is that the PE film in Comparative Example 1 has a mesh structure.

[0114] Comparative Example 2: The preparation method and the first mixture and its composition are the same as those of Comparative Example 3. The difference is that the raw materials and their composition of the second mixture in Comparative Example 2 are the same as those of the first mixture. That is, the second mixture includes 35 parts of LDPE resin, 65 parts of HDPE resin, 5 parts of erucamide and 8 parts of white PE masterbatch.

[0115] Comparative Example 3: The preparation method and raw materials and composition of the second mixture are the same as those of Comparative Example 3. The difference is that only the second mixture is used to prepare a single-layer membrane in Comparative Example 3.

[0116] PE films were prepared using the methods described in Comparative Examples 1-3, and their performance was tested. The specific results are shown in Table 2 below:

[0117] Table 2 Performance test results of Comparative Examples 1-3

[0118]

[0119]

[0120] As can be seen from the test results in Table 2, the PE film in Comparative Example 1 has a mesh structure, which leads to a decrease in the tensile strength and elongation at break of the obtained PE film.

[0121] As can be seen from the test results in Table 2, since the second mixture of Comparative Example 2 uses a blend of multiple types of PE resins, the advantages of mLLDPE resin cannot be fully utilized, resulting in a decrease in the tensile strength and elongation at break of the PE film.

[0122] As can be seen from the test results in Table 2, since Comparative Example 3 only uses a single-layer film, the resulting PE film is thinner and has a lower weight, which leads to a decrease in its performance. In addition, since it is equivalent to only having the intermediate film layer of Example 3, without the upper and lower film layers, its heat sealing strength is significantly lower than that of Example 3. At the same time, since the second raw material does not contain a slip agent, its coefficient of friction increases.

[0123] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A low-weight, high-performance PE film with a fruit peel texture, characterized in that: The ultra-low weight, high-performance fruit peel textured PE film has a tensile strength ≥5.50 N / 25mm, an elongation at break ≥350%, and a coefficient of friction ≤0.

60. The ultra-low weight high-performance fruit peel textured PE film comprises an upper film layer, a middle film layer and a lower film layer distributed in turn from top to bottom, the upper film layer and the lower film layer are obtained by melting extrusion of the first mixed material through a double screw extruder, and the middle film layer is obtained by melting extrusion of the second mixed material through a double screw extruder; wherein the weight of the PE film is 11-15 g / m 2 , and the PE film is in pear texture or litchi texture. According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin and 5-8 parts of slip agent; The second mixture comprises 85-95 parts of mLLDPE resin and 5-15 parts of color masterbatch, calculated by mass.

2. The ultra-low weight, high-performance fruit peel textured PE film according to claim 1, characterized in that: The first mixture also includes color masterbatch; According to the mass fractions, the first mixture includes 25-35 parts of LDPE resin, 65-75 parts of HDPE resin, 5-8 parts of slip agent and 5-10 parts of color masterbatch.

3. The ultra-low weight, high-performance fruit peel textured PE film according to claim 1, characterized in that: The first mixture comprises 35 parts of LDPE resin, 65 parts of HDPE resin, 8 parts of slip agent, and 5 parts of color masterbatch; The second mixture comprises 90 parts of mLLDPE resin and 10 parts of color masterbatch.

4. The ultra-low weight, high-performance fruit peel textured PE film according to claim 1, characterized in that: The upper film layer has a weight of 2.5 to 3.5 g / m 2 The intermediate film layer has a weight of 6 to 8 g / m 2 The lower film layer has a weight of 2.5 to 3.5 g / m 2 .

5. The ultra-low weight, high-performance fruit peel textured PE film according to claim 1, characterized in that: The slip agent includes at least one of oleamide and erucamide.

6. The ultra-low weight, high-performance fruit peel textured PE film according to claim 2, characterized in that: The color masterbatch includes either black PE masterbatch or white PE masterbatch.

7. A method for preparing an ultra-low weight, high-performance fruit peel textured PE film, characterized in that, The method for preparing the ultra-low weight, high-performance fruit peel textured PE film as described in any one of claims 2 to 6 includes the following steps: S1. HDPE resin, LDPE resin, color masterbatch and slip agent are mixed evenly according to the formula to obtain the first mixture; LDPE resin and color masterbatch are mixed evenly according to the formula to obtain the second mixture. S2. The first mixture is added to the screw of a twin-screw extruder at a speed of 25-30 r / min for melting, and then conveyed to the first and third flow channels of the die cavity while maintaining the temperature. The second mixture is added to the screw of a twin-screw extruder at a speed of 35-40 r / min for melting, and then conveyed to the second flow channel of the die cavity while maintaining the temperature. The melt in the first, second, and third flow channels converges at the die lip of the die head and undergoes three-layer co-extrusion. The intermediate film is formed by pressing the film through the casting steel roller and the casting pressure roller. S3. After embossing, matte finishing and cooling the intermediate film material, the surface of the intermediate film material is then corona treated, and after winding, an ultra-low weight, high-performance fruit peel textured PE film is obtained.

8. The method for preparing an ultra-low weight, high-performance fruit peel textured PE film according to claim 7, characterized in that: In step S2, the temperature of the casting steel roll and the casting pressure roll is 20-28°C, and the mutual clamping force between the casting steel roll and the casting pressure roll is 4-6 kg / cm. 2 .

9. The method for preparing an ultra-low weight, high-performance fruit peel textured PE film according to claim 7, characterized in that: In step S3, the corona current in the corona treatment step is 3-5A.

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