High-performance wrapping film as well as preparation method and application thereof

Abstract

The invention discloses a high-performance wrapping film which comprises the following components in percentage by mass: 55-75% of a main body material; 22%-37% of a filling material; 2%-8% of a toughening material; 1%-2% of a tackifying material; wherein the main body material is one or more of C8 metallocene, C6 metallocene and C4 metallocene. The high-performance wrapping film is simple in processing technology, beneficial to production and high in economical efficiency; and moreover, the advantages in the aspects of appearance, mechanical property, usage amount and the like are remarkable, the problems of many defects of a traditional wrapping film can be effectively solved, and the application prospect in the field of logistics packaging is wide.

Description

Technical Field

[0001] The present application relates to the technical field of packaging materials, and more specifically, to a novel high-performance stretch film formulation, a preparation method, and an application thereof. Background Art

[0002] In recent years, stretch film has been widely used in the packaging and logistics industry due to its high elongation, self-adhesion, puncture resistance, and tear resistance. With the rapid development of the logistics industry and the increasing demand for stretch film, the industry's requirements for stretch film packaging materials are also increasing. The following shows the test indicators of industry-standard 1.5-wire machine-use stretch film and the performance data of conventional stretch film on the market.

[0003] Test item Industry standard Conventional stretch wrap film Longitudinal breaking tension ≥ 35 MPa 35.47 Transverse breaking tension ≥ 18 MPa 19.96 Longitudinal breaking elongation ≥300％ 674.9 Transverse breaking elongation ≥600％ 916.9 Puncture resistance ≥15N 15.5 Puncture elongation ≥ 60 mm 84.25 Adhesion <![CDATA[≥5N / cm 2 ]]> 6.21 Longitudinal tear resistance ≥ 100 gf 125.43 Transverse tear resistance ≥ 350 gf 412.42

[0004] The existing stretch film has problems in performance such as easy breaking, large single-pallet consumption, and low economy, which makes it difficult to meet the high performance requirements of modern logistics for packaging materials. Therefore, it is urgent to develop a new high-performance stretch film that can meet the current high usage requirements. Summary of the Invention

[0005] The main purpose of this application is to provide a new type of stretch film with the characteristics of high strength, good toughness, not easy to break, and light single-support usage. Compared with existing conventional stretch films, the product performance, quality and economic efficiency are significantly improved, and the problems raised in the above background technology are well solved.

[0006] To achieve the above objectives, according to one aspect of the present application, a high-performance stretch film is provided, the components of which, by weight percentage, include:

[0007] Main material: 55%-75%;

[0008] Filling material: 22%-37%;

[0009] Toughening material: 2%-8%;

[0010] Tackifying material: 1%-2%;

[0011] Wherein, the main material is one or more of C8 metallocene, C6 metallocene, and C4 metallocene.

[0012] Furthermore, the high-performance stretch film comprises, by weight:

[0013] Main material: 55-75%;

[0014] Filling material: 22%-37%;

[0015] Toughening material: 2%-8%;

[0016] Tackifying material: 1%-2%;

[0017] The host material is a mixture of C8 metallocene and C6 metallocene.

[0018] Furthermore, the high-performance stretch film comprises, by weight:

[0019] C8 metallocene: 50%-60%;

[0020] C6 metallocene: 5%-15%;

[0021] Filling material: 33%-37%;

[0022] Toughening material: 2%-8%;

[0023] Tackifying material: 1%-2%.

[0024] Furthermore, the filling material is one or more of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, and metallocene polyethylene.

[0025] Furthermore, the toughening material is one or more of polypropylene-based elastomer, polyolefin elastomer, styrene-based elastomer, and α-olefin elastomer.

[0026] Furthermore, the tackifying material is a tackifier.

[0027] Preferably, the tackifier is one or more of ethylene-vinyl acetate copolymer, polyisobutylene, polymerized rosin glycerol ester, polybutene, and polyacrylic acid.

[0028] In the high-performance stretch film of this application, the main material can improve the tensile strength of the stretch film while also imparting good tensile toughness. By weight, the main material in this application accounts for 55%-75%, preferably 60-71%. The main material can be one or more of a C8 metallocene, a C6 metallocene, or a C4 metallocene. Further preferably, the main material is a mixture of a C8 metallocene and a C6 metallocene, wherein, by weight, the C8 metallocene content is 50-60% and the C6 metallocene content is 5-15%. Specifically, the linear structure of the C8 metallocene improves the balance of mechanical properties in the longitudinal and transverse directions of the stretch film, particularly enhancing tear strength. The dense molecular weight distribution of the C6 metallocene enhances tensile elongation at break and impact strength. Experiments have shown that combining the two in the aforementioned proportions creates a complementary effect, resulting in optimal overall mechanical properties. Preferably, the C8 metallocene content is 55-58% and the C6 metallocene content is 8-13%.

[0029] The filler material in this application can effectively reduce compounding costs and improve the market competitiveness of the finished stretch film. By weight, the filler content in this application is 22%-37%, preferably 18-21%. The filler material in this application is one or more of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, and metallocene polyethylene, with linear low-density polyethylene being preferred. Linear low-density polyethylene offers significant advantages in overall performance, processing flexibility, and cost-effectiveness, making it particularly suitable for packaging films that require a balance of strength, flexibility, and affordability.

[0030] The toughening material in this application enhances the tensile strength of the stretch film, making it less susceptible to breakage during stretching and capable of withstanding significant tensile forces. By weight, the toughening material content in this application ranges from 2% to 8%, preferably 4% to 6%. The toughening material in this application is one or more of a polypropylene-based elastomer, a polyolefin elastomer, a styrene-based elastomer, or an α-olefin elastomer, with polyolefin elastomer being preferred. Polyolefin elastomers offer improved flexibility, transparency, and aging resistance, and their overall performance, processing efficiency, and cost-effectiveness surpass those of other raw materials.

[0031] The tackifying material in this application is used to improve the self-adhesiveness of the stretch film, so that the films can fit more tightly together when the stretch film is used to wrap items. The tackifying material in this application is a tackifier, and the tackifier in this application accounts for 1%-2% by mass, preferably 1.5-2%. The tackifier in this application is one or more of ethylene-vinyl acetate copolymer, polyisobutylene, polymerized rosin glycerol ester, polybutene, polyacrylic acid, etc., preferably polyisobutylene. The viscosity of polyisobutylene can be precisely controlled by adjusting the molecular weight and the amount added, and the amount added is small and cost-effective; at the same time, it has good compatibility and can be evenly dispersed without complex processes, and does not affect the mechanical strength and tensile strength of the stretch film itself.

[0032] The high-performance stretch film of the present application innovatively uses five types of raw materials: C8 metallocene, C6 metallocene, linear low-density polyethylene, tackifier, and toughening material. Different raw materials complement each other's advantages to develop a high-performance stretch film.

[0033] According to a second aspect of the present application, a method for preparing the aforementioned high-performance stretch film is provided, comprising the following steps:

[0034] S1. Batching and Mixing: An automatic batching system is used to mix the raw materials in the correct proportions. This system utilizes advanced electronic weighing and automated control technologies to accurately measure each type of raw material. After metering, the mixture is thoroughly mixed before entering the screw hopper. This thorough mixing prevents the dispersion of raw materials during transportation due to varying specific gravities.

[0035] S2. Melt extrusion: Multi-layer screws and multi-layer distributors are used for production; in some embodiments, at least 3 layers of screws and 5 layers of distributors are used. The multi-layer screw can compress, shear and mix the material multiple times, so that the material is mixed more evenly in the molten state. As the number of screw and distributor layers increases, the flow of the material during the extrusion process is more stable and the distribution is more uniform, which can further improve the composite performance of the film. In the melt extrusion process, the control of process parameters such as temperature and pressure is also very critical. In this application, the melt extrusion temperature is controlled at 220-260°C; too high a temperature may cause decomposition of the raw materials and degradation of performance; too low a temperature will cause insufficient melting of the material, affecting the extrusion effect. Control the pressure of the main screw at 10-16Mpa and the auxiliary screw at 5-9Mpa; too high a pressure may cause damage to the equipment, and too low a pressure cannot guarantee the extrusion speed of the material and the quality of the product.

[0036] S3. Cooling and Setting: The cast film extruded in step S2 is stretched over the surface of a cold roller to gradually cool and set. The cold roller temperature is controlled between 35°C and 45°C during the stretching process. Cooling and setting is a critical step in determining the tensile properties of stretch film. Maintaining this temperature range ensures uniform and stable cooling and setting of the film. If the cold roller temperature is too low, the film may develop internal stress due to rapid cooling, leading to problems such as cracking during subsequent use. If the cold roller temperature is too high, the film will not cool and set in time, affecting production efficiency and product quality. Furthermore, it is important to avoid the negative impact of low or high temperatures on the film's cooling and setting. The production workshop should maintain a relatively stable ambient temperature to provide optimal conditions for the film's cooling and setting. An appropriate cooling and setting process, combined with well-controlled production ambient temperature, ensures the quality of the stretch film.

[0037] S4. Online trimming: The shaped stretch film is cut into rolls of different sizes through a slitting mechanism. It is recommended to use ceramic blades for slitting, which are sharper and more durable than ordinary iron blades, and the trimmed product end surface quality is better.

[0038] S5. Winding: When winding the film, a lower tension is required. Reducing the tension requires that the speed difference between the forming roller and the winding roller be less than 4m / min, thereby reducing the stress in the finished film and improving the winding quality of the product.

[0039] S6. Die Maintenance: As the exit port for cast film, the die plays a critical role in product quality. The quality and condition of the die directly impact key performance indicators such as thickness uniformity and surface smoothness. Therefore, routine maintenance is crucial to prevent carbon deposits inside the die and prevent failure of the die thickness adjustment screws. Before starting the machine, clean the die lip with a copper sheet to remove impurities and dirt from the die surface. This ensures that the molten material can pass smoothly through the die during extrusion, avoiding defects such as scratches and holes.

[0040] According to a third aspect of the present application, there is provided application of the above-mentioned high-performance stretch film in the field of packaging.

[0041] Compared to existing technologies, the high-performance stretch film of this application incorporates a combination of raw materials with different properties, employing a combination of high- and low-carbon metallocenes, along with polyolefin elastomers for enhanced performance. This integrates the advantages of each raw material to complement each other, thereby enhancing the mechanical properties of the stretch film itself. Furthermore, through continuous exploration and verification during production, key points affecting product quality are identified and controlled, resulting in a high-performance stretch film with improved performance that meets current usage requirements. The high-performance stretch film produced using this stretch film formula and process exhibits excellent tensile properties and strength, is not only resistant to breaking, but also requires less material for the same number of wraps, resulting in greater economic efficiency. Furthermore, the process is simple and cost-effective, aligning with the development trend of green environmental protection, and possesses broad application prospects and market value. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other in any way.

[0043] The high-performance stretch film of the present application comprises the following components by weight:

[0044] Main material: 55%-75%;

[0045] Filling material: 22%-37%;

[0046] Toughening material: 2%-8%;

[0047] Tackifying material: 1%-2%;

[0048] Wherein, the main material is one or more of C8 metallocene, C6 metallocene, and C4 metallocene.

[0049] Furthermore, the raw material formula of the stretch film of the present application includes the following components by mass: 50%-60% C8 metallocene, 5%-15% C6 metallocene, 22%-37% linear low-density polyethylene, 1%-2% polyisobutylene and 2%-8% polyolefin elastomer.

[0050] Specific examples of the high-performance stretch film formulations of the present application are further shown below in a table.

[0051] Table 1 Raw material ratios of various examples

[0052]

[0053]

[0054] Wherein, the preparation method of embodiment 1-3 is as follows:

[0055] S1. Ingredient mixing: Use automatic batching system to mix the raw materials according to the proportion.

[0056] S2. Melt extrusion: Use 4-layer screw and 6-layer distributor for production, control the melt extrusion temperature to 230℃; control the pressure to 12Mpa for the main screw and 6Mpa for the auxiliary screw.

[0057] S3, cooling and shaping: the film extruded in step S2 is stretched on the surface of a cold roller to gradually cool and shape it. The temperature of the cold roller is controlled at 35°C during the stretching process.

[0058] S4. Online trimming: The shaped stretch film is cut into rolls of different sizes by ceramic blades.

[0059] S5. Winding: When winding the film, a lower tension should be used for winding, and the speed difference between the forming roller and the winding roller should be less than 4m / min.

[0060] S6. Mould maintenance.

[0061] The preparation methods of Examples 4-6 are as follows:

[0062] S1. Ingredient mixing: Use automatic batching system to mix the raw materials according to the proportion.

[0063] S2. Melt extrusion: Use 4-layer screw and 6-layer distributor for production, control the melt extrusion temperature to 260℃; control the pressure to 16Mpa for the main screw and 9Mpa for the auxiliary screw.

[0064] S3, cooling and shaping: the film extruded in step S2 is stretched on the surface of a cold roller to gradually cool and shape it. The temperature of the cold roller is controlled at 45°C during the stretching process.

[0065] S4. Online trimming: The shaped stretch film is cut into rolls of different sizes by ceramic blades.

[0066] S5. Winding: When winding the film, a lower tension should be used for winding, and the speed difference between the forming roller and the winding roller should be less than 4m / min.

[0067] S6. Mould maintenance.

[0068] In order to further illustrate the beneficial effects of the present application, currently commonly used stretch films, stretch films with different content ratios, and stretch films prepared by different processes (Comparative Examples 1-3) were selected for performance comparison tests.

[0069] The comparative example stretch film formula is as follows:

[0070] Comparative Example 1

[0071] C8 metallocene: 82.9%

[0072] Linear low-density polyethylene: 16%

[0073] Polyisobutylene: 1.1%.

[0074] Comparative Example 2

[0075] C8 metallocene: 48%

[0076] C6 metallocene: 17%

[0077] Linear low-density polyethylene: 24%

[0078] Polyolefin elastomer: 8.6%

[0079] Polyisobutylene: 2.4%.

[0080] Comparative Example 3

[0081] C8 metallocene: 58%

[0082] C6 metallocene: 9%

[0083] Linear low-density polyethylene: 25%

[0084] Polyolefin elastomer: 6.6%

[0085] Polyisobutylene: 1.4%.

[0086] The preparation method of Comparative Example 3 is as follows:

[0087] S1. Ingredient mixing: Use automatic batching system to mix the raw materials according to the proportion.

[0088] S2. Melt extrusion: Use 4-layer screw and 6-layer distributor for production, control the melt extrusion temperature to 215℃; control the pressure to 9Mpa for the main screw and 6Mpa for the auxiliary screw.

[0089] S3, cooling and shaping: the film extruded in step S2 is stretched on the surface of a cold roller to gradually cool and shape it. The temperature of the cold roller is controlled at 33°C during the stretching process.

[0090] S4. Online trimming: The shaped stretch film is cut into rolls of different sizes by ceramic blades.

[0091] S5. Winding: When winding the film, a lower tension should be used for winding, and the speed difference between the forming roller and the winding roller should be less than 4m / min.

[0092] S6. Mould maintenance.

[0093] Table 4 shows the performance test results of the stretch films produced using the formulations of Examples 1 to 6 and Comparative Examples 1 to 3.

[0094] Table 4 Stretch film performance test results

[0095]

[0096]

[0097] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0098] From the above formula test examples, it can be seen that by rationally designing the stretch film formula and controlling the production process parameters, the performance data of the resulting stretch film are all superior to the control examples; in particular, key performance indicators such as longitudinal elongation at break, transverse elongation at break, puncture resistance, puncture extension, longitudinal tear resistance, and transverse tear resistance have all been significantly improved. This shows that the stretch film of this application has made a qualitative leap in tensile properties, tear resistance, and puncture resistance, and can better meet the actual needs of logistics packaging. In addition, in terms of the comparison of the amount of stretch film used for single-pallet products, the amount of single-pallet stretch film used is greatly reduced, which can significantly reduce the cost of using stretch film for packaging single-pallet products. For logistics companies, this has important economic significance and can effectively improve their competitiveness.

[0099] In summary, the high-performance stretch film of this application possesses excellent tensile properties and strength, making it not only resistant to breaking, but also, with the same number of wraps, requiring less material and achieving greater economic efficiency. Furthermore, its simple processing and low cost align with the development trend of green environmental protection, resulting in broad application prospects and market value.

[0100] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, and the like made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0101] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit the present application. Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-performance stretch film, characterized in that: Calculated by mass, its components include: Main material: 55%-75%; Filling material: 22%-37%; Toughening material: 2%-8%; Tackifying material: 1%-2%; Wherein, the main material is one or more of C8 metallocene, C6 metallocene, and C4 metallocene.

2. The high-performance stretch film according to claim 1, characterized in that: Calculated by mass, its components include: Main material: 55-75%; Filling material: 22%-37%; Toughening material: 2%-8%; Tackifying material: 1%-2%; The host material is a mixture of C8 metallocene and C6 metallocene.

3. The high-performance stretch film according to claim 2, characterized in that: Calculated by mass, its components include: C8 metallocene: 50%-60%; C6 metallocene: 5%-15%; Filling material: 22%-37%; Toughening material: 2%-8%; Tackifying material: 1%-2%.

4. The high-performance stretch film according to claim 1, characterized in that: The filling material is one or more of low-density polyethylene, linear low-density polyethylene, high-density polyethylene, and metallocene polyethylene.

5. The high-performance stretch film according to claim 1, characterized in that: The toughening material is one or more of polypropylene-based elastomer, polyolefin elastomer, styrene-based elastomer, and α-olefin elastomer.

6. The high-performance stretch film according to claim 1, characterized in that: The tackifying material is a tackifier.

7. The high-performance stretch film according to claim 6, characterized in that: The tackifier is one or more of ethylene-vinyl acetate copolymer, polyisobutylene, polymerized rosin glycerol ester, polybutene, and polyacrylic acid.

8. A method for preparing a high-performance stretch film according to any one of claims 1 to 7, characterized in that: It includes ingredient mixing, melt extrusion, cooling and shaping, online trimming, winding and mold maintenance steps.

9. The method for preparing a high-performance stretch film according to claim 8, wherein: In the melt extrusion step, the melt extrusion temperature is controlled to be 220-260°C.

10. Use of the high-performance stretch film according to any one of claims 1 to 7 in the field of packaging.

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