Lining liquid bag for ISO (International Standardization Organization) tank car and preparation method thereof

Abstract

The invention discloses an ISO tank car lining liquid bag and a preparation method thereof, and belongs to the technical field of packaging, the ISO tank car lining liquid bag comprises a bag body, the bag body is formed by heat sealing of a polyethylene membrane, and a heat sealing line is formed at the heat sealing position, and the ISO tank car lining liquid bag is characterized in that a material nozzle is heat-sealed at the rear part of the bag body and is communicated with an inner cavity of the bag body; the material nozzle is characterized in that the material nozzle is prepared from 58-62% by mass of linear low-density polyethylene and the balance of high-density polyethylene; a disc is further arranged on the bag body in a heat sealing mode, a protruding rib is arranged on the top wall of the disc, a connecting hole is formed between the protruding rib and the disc or the protruding rib is provided with a connecting hole, and the disc is made of, by mass, 71%-78% of linear low-density polyethylene, 17%-23% of high-density polyethylene and 4%-6% of polyolefin elastomer. According to the packaging bag, the material nozzle and the disc have good compatibility with the polyethylene film, the heat sealing strength of the material nozzle and the bag body and the flexibility of the material nozzle can be enhanced, and the lining liquid bag can be dragged through the disc for full discharging.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging bags, and in particular relates to an ISO tank truck liner liquid bag and a preparation method thereof. Background Art

[0002] ISO tank trucks not only have strong protective strength, but also have good sealing properties. They are often used to transport flammable, explosive or highly corrosive hazardous chemicals, prevent hazardous chemicals from coming into contact with the air or prevent toxic and harmful vapors from leaking into the air, thus becoming an essential means of transport for hazardous chemicals.

[0003] As described in the patent with announcement number CN220975304U, the existing ISO tank trucks are usually connected with nitrogen after loading to achieve nitrogen sealing inside the tank body, prevent vaporized dangerous pieces from escaping into the air, and further enhance the protection effect. This type of tank truck not only adds nitrogen filling equipment and operating procedures, which increases equipment costs and reduces loading efficiency; it also needs to be cleaned after unloading to avoid cross contamination with the subsequent loaded materials, which reduces the effective working time of the tank truck and indirectly increases the use cost of the tank truck.

[0004] Therefore, the inventor envisioned developing a liner bag and submitted a utility model patent application to the Intellectual Property Office of my country on September 20, 2024 for the relevant technology. Its application number is 202422296299.1. However, during the implementation process, the following problems were found: 1. The segmented connection structure of the bag body along the front and back directions complicates the process of making the bag body and reduces the processing efficiency of the bag body; 2. The heat sealing strength between the nozzle and the bag body is not enough, and there is also the problem of being too hard, making it difficult to pass through the valve port of the tank body; 3. When unloading, there is easily residual material in the liner bag, which makes the unloading incomplete and causes waste of the transported materials. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an ISO tank truck liner liquid bag and a preparation method thereof, which can enhance the heat-sealing strength between the nozzle and the bag body and the flexibility of the nozzle itself, and can also fully unload the liner liquid bag by dragging the liner liquid bag by a disc.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: design an ISO tank truck liner liquid bag, including a bag body, the bag body is formed by heat-sealing a polyethylene film, and a heat-sealing line is formed at the heat-sealing part, characterized in that: a nozzle is heat-sealed at the rear of the bag body, and the nozzle is connected to the inner cavity of the bag body, characterized in that: the nozzle is made of linear low-density polyethylene with a mass percentage of 58-62% and high-density polyethylene as the balance; The bag body is also heat-sealed with a disc, the top wall of the disc is provided with a convex rib, a connecting hole is formed between the convex rib and the disc or a connecting hole is opened on the convex rib, and the disc is made of the following raw materials in percentage by mass: Linear low density polyethylene 71~78% High-density polyethylene 17-23% Polyolefin elastomer 4-6%.

[0007] Furthermore, the polyethylene film is rhombus-shaped, and the heat sealing line is divided into a first heat sealing part and a second heat sealing part connected to the first heat sealing part. The first heat sealing part is arranged along the periphery of the polyethylene film, and the second heat sealing part is located on both sides of a diagonal line of the polyethylene film. The disk is located in the enclosed area of ​​the first heat sealing part and the second heat sealing part.

[0008] Furthermore, the polyethylene film is formed by overlapping an inner film and an outer film, the thickness of the outer film is 105-125 μm, and the thickness of the inner film is 140-160 μm.

[0009] Furthermore, the inner film and the outer film are composed of an outermost layer, a second outer layer, a middle layer, a second inner layer and an innermost layer from the outside to the inside; the outermost layer and the innermost layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 6~10% High-density polyethylene 1~3% Metallocene polyethylene 1~3% Polyolefin elastomer 0.7~1.3% The sub-outer layer and the sub-inner layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 2~4% High-density polyethylene 4.5~7.5% Metallocene polyethylene 6~10% Polyolefin elastomer 3~5% The middle layer is made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 2~4% High density polyethylene 3~5% Metallocene polyethylene 15~25% Polyolefin elastomer 4-6%.

[0010] Furthermore, the outermost layer and the innermost layer are both made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 8% High density polyethylene 2% Metallocene polyethylene 2% Polyolefin elastomer 1% The sub-outer layer and the sub-inner layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 3% High density polyethylene 6% Metallocene polyethylene 8% Polyolefin elastomer 4% The middle layer is made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 3% High density polyethylene 4% Metallocene polyethylene 20% Polyolefin elastomer 5%.

[0011] Furthermore, the nozzle is made of the following raw materials in percentage by mass: Linear low density polyethylene 60% High density polyethylene 40%.

[0012] Furthermore, the disc is made of the following raw materials in percentage by mass: Linear low density polyethylene 75 % High density polyethylene 20% Polyolefin elastomer 5%.

[0013] The present invention also provides a method for preparing an ISO tank truck liner liquid bag, comprising the following steps: (1) Preparing a nozzle: mixing linear low-density polyethylene and high-density polyethylene into a first mixture, wherein the linear low-density polyethylene accounts for 58-62% by weight of the first mixture and the remainder is high-density polyethylene, and the first mixture is kneaded and molded to obtain a nozzle; (2) Preparing a disc: mixing linear low-density polyethylene, high-density polyethylene and polyolefin elastomer into a second mixture, wherein the mass proportion of the linear low-density polyethylene in the second mixture is 71-78%, the mass proportion of the high-density polyethylene in the second mixture is 17-23%, and the mass proportion of the polyolefin elastomer in the second mixture is 4-6%. The second mixture is kneaded and then compression molded to obtain a disc having a rib on the top wall, wherein a connecting hole is enclosed between the rib and the top wall of the disc or a connecting hole is opened on the rib; (3) Preparing a first special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a third mixed material, and granulating the third mixed material to obtain the first special material; the mass proportion of linear low-density polyethylene in the third mixed material is 6-10%, the mass proportion of high-density polyethylene in the third mixed material is 1-3%, the mass proportion of metallocene polyethylene in the third mixed material is 1-3%, and the mass proportion of polyolefin elastomer in the third mixed material is 0.7-1.3%; (4) Preparing a second special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a fourth mixed material, and granulating the fourth mixed material to obtain the second special material; the mass proportion of linear low-density polyethylene in the fourth mixed material is 2-4%, the mass proportion of high-density polyethylene in the fourth mixed material is 4.5-7.5%, the mass proportion of metallocene polyethylene in the fourth mixed material is 6-10%, and the mass proportion of polyolefin elastomer in the fourth mixed material is 3-5%; (5) Preparing the third special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a fifth mixed material, and granulating the fifth mixed material to obtain the third special material; the mass proportion of linear low-density polyethylene in the fifth mixed material is 2-4%, the mass proportion of high-density polyethylene in the fifth mixed material is 3-5%, the mass proportion of metallocene polyethylene in the fifth mixed material is 15-25%, and the mass proportion of polyolefin elastomer in the fifth mixed material is 4-6%; (6) Preparing a polyethylene film: the first special material prepared in step (3), the second special material prepared in step (4), the third special material prepared in step (5), the second special material prepared in step (4), and the first special material prepared in step (3) are sequentially subjected to multi-layer co-extrusion blow molding to form a polyethylene film having an outermost layer, a second outermost layer, a middle layer, a second innermost layer, and a third innermost layer arranged from the outside to the inside; (7) Bag making: The polyethylene film obtained in step (6) is heat-sealed to form a bag body, and a heat-sealed line is formed at the heat-sealed part; (8) Configuring accessories: Heat-sealing the nozzle prepared in step (1) and the disc prepared in step (2) onto the bag body prepared in step (7), with the nozzle being located at the rear of the bottom wall of the bag body and the disc being located on both sides of the top wall of the bag body.

[0014] Furthermore, the heat sealing line of step (7) includes a first heat sealing portion and a second heat sealing portion connected to the first heat sealing portion, the first heat sealing portion is arranged along the periphery of the polyethylene film, the second heat sealing portion is located on both sides of a diagonal of the polyethylene film, and the disk is located in the enclosed area of ​​the first heat sealing portion and the second heat sealing portion.

[0015] Furthermore, the inner film and the outer film obtained in sequence in step (6) are overlapped with each other to form a polyethylene film sheet.

[0016] Furthermore, in step (1), the mixing temperature of the first mixture is 220-280°C.

[0017] Furthermore, in step (2), the mixing temperature of the second mixture is 260-300°C.

[0018] Furthermore, the granulation temperature of the third mixed material in step (3), the granulation temperature of the fourth mixed material in step (4), and the granulation temperature of the fifth mixed material in step (5) are all 180-200°C.

[0019] Furthermore, in step (6), the extrusion temperature of the multilayer co-extrusion is 170-190°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adjusts the formula of the nozzle and the disc so that the nozzle and the disc have good compatibility with the polyethylene film, enhances the connection strength with the bag body, and enables the nozzle itself to achieve a good balance between strength and flexibility, so that it can not only achieve a certain supporting effect and be clamped on the valve port of the tank body, but also have a certain flexibility and deformation ability, so that it is easy to pass through the valve port of the tank body; it can also make the disc have good toughness and plastic deformation ability to avoid damaging the bag body. At the same time, by connecting a draw rope to the disc and pulling the two sides of the bag body, the material can be gathered to the nozzle for easy discharge.

[0021] 2. The polyethylene film is designed to be diamond-shaped, and the first heat-sealing part in the heat-sealing line is arranged along the periphery of the polyethylene film, and the second heat-sealing part is located on both sides of a diagonal line of the polyethylene film, so that the inner cavity of the bag body is shuttle-shaped, which greatly simplifies the manufacturing process of the bag body and improves its manufacturing efficiency; the disc is arranged in the enclosed area of ​​the first heat-sealing part and the second heat-sealing part, so that the connection of the disc is not connected to the inner cavity of the bag body, while the bag body can be dragged by the disc, and damage to the bag body is avoided.

[0022] 3. By adjusting the formula of the polyethylene film, the strength of the polyethylene film itself and the heat-sealed connection strength can be enhanced while maintaining a high connection strength with the nozzle and the disc, making it suitable for packaging liquid materials with a larger specific gravity.

[0023] 4. The present invention simplifies the preparation process of the bag body while being able to meet the requirements of the special-shaped space of the tank truck. It can increase the flexibility of the nozzle and the connection strength between the nozzle and the bag body, making it more suitable for use in the tank truck and easy to promote and apply in the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the connection structure between the nozzle and the bag body.

[0025] The reference numerals in the drawings are: 1, bag body; 11, outer film; 12, inner film; 2, heat sealing line; 21, first heat sealing portion; 22, second heat sealing portion; 3, nozzle; 4, disc; 41, convex rib. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] When the present invention is in use, the side close to the packaged object is defined as the inner side, and the other side away from the packaged object is defined as the outer side; the end close to the front of the tank truck is defined as the front end, and the other end close to the rear of the tank truck is defined as the rear end. Embodiment 1

[0028] ISO tank truck liner liquid bag is produced by the following steps: (1) Preparing a nozzle: Linear low-density polyethylene and high-density polyethylene are mixed into a first mixture, wherein the linear low-density polyethylene accounts for 58% by weight of the first mixture and the remainder is high-density polyethylene. The first mixture is kneaded and then compression molded to obtain a nozzle. The kneading temperature of the first mixture is 220°C.

[0029] (2) Preparing a disc: Linear low-density polyethylene, high-density polyethylene and polyolefin elastomer are mixed into a second mixture, wherein the mass proportion of linear low-density polyethylene in the second mixture is 71%, the mass proportion of high-density polyethylene in the second mixture is 23%, and the mass proportion of polyolefin elastomer in the second mixture is 6%. The second mixture is kneaded and molded to obtain a disc having a rib on the top wall, wherein a connecting hole is enclosed between the rib and the top wall of the disc or a connecting hole is opened on the rib. The kneading temperature of the second mixture is 260°C.

[0030] (3) Preparing a first special material: linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer are mixed into a third mixture, and the third mixture is granulated to obtain the first special material. The granulation temperature of the third mixture is 180°C; the mass proportion of linear low-density polyethylene in the third mixture is 10%, the mass proportion of high-density polyethylene in the third mixture is 1%, the mass proportion of metallocene polyethylene in the third mixture is 1%, and the mass proportion of polyolefin elastomer in the third mixture is 1%.

[0031] (4) Preparation of the second special material: linear low density polyethylene, high density polyethylene, metallocene polyethylene and polyolefin elastomer are mixed into a fourth mixture, and the fourth mixture is granulated to obtain the second special material. The granulation temperature of the fourth mixture is 180°C; the mass proportion of linear low density polyethylene in the fourth mixture is 4%, the mass proportion of high density polyethylene in the fourth mixture is 4.5%, the mass proportion of metallocene polyethylene in the fourth mixture is 8%, and the mass proportion of polyolefin elastomer in the fourth mixture is 5%.

[0032] (5) Preparation of the third special material: linear low density polyethylene, high density polyethylene, metallocene polyethylene and polyolefin elastomer are mixed into a fifth mixture, and the fifth mixture is granulated to obtain the third special material. The granulation temperature of the fifth mixture is 180°C; the mass proportion of linear low density polyethylene in the fifth mixture is 2%, the mass proportion of high density polyethylene in the fifth mixture is 5%, the mass proportion of metallocene polyethylene in the fifth mixture is 18%, and the mass proportion of polyolefin elastomer in the fifth mixture is 6%.

[0033] (6) Preparing a polyethylene film sheet: The first special material prepared in step (3), the second special material prepared in step (4), the third special material prepared in step (5), the second special material prepared in step (4), and the first special material prepared in step (3) are sequentially subjected to multi-layer co-extrusion blow molding to form an outermost layer, a second outermost layer, an intermediate layer, a second innermost layer, and a film arranged from outside to inside, thereby preparing an inner film and an outer film respectively. The extrusion temperature of the multi-layer co-extrusion is 170° C., the thickness of the outer film is 105 μm, and the thickness of the inner film is 160 μm. The outer film and the inner film are overlapped in order from outside to inside to serve as a polyethylene film sheet for preparing a bag body, and the polyethylene film sheet is cut into a rhombus.

[0034] (7) Bag making: The polyethylene film sheet obtained in step (6) is heat-sealed to form a bag body, and a heat-sealed line is formed at the heat-sealed portion. The heat-sealed line consists of a first heat-sealed portion and a second heat-sealed portion connected to the first heat-sealed portion. The first heat-sealed portion is arranged along the periphery of the polyethylene film sheet, and the second heat-sealed portion is located on both sides of a diagonal line of the polyethylene film sheet.

[0035] (8) Configuring accessories: Heat-sealing the nozzle prepared in step (1) and the disc prepared in step (2) on the bag body prepared in step (7), wherein the nozzle is located at the rear of the bottom wall of the bag body and communicates with the inner cavity of the bag body. The disc is located on the top wall of the bag body within the enclosed area of ​​the first heat-sealing portion and the second heat-sealing portion.

[0036] So made as Figure 1 The inner cavity of the liner fluid bag shown in the figure is shuttle-shaped, that is, the bag body 1 is formed by heat-sealing a diamond-shaped polyethylene film sheet, and the polyethylene film sheet is formed by overlapping an outer film 11 and an inner film 12 arranged in sequence from the outside to the inside, and a heat-sealing line 2 is formed at the heat-sealing point. The heat-sealing line 2 is divided into a first heat-sealing part 21 and a second heat-sealing part 22 connected to the first heat-sealing part 21. The first heat-sealing part 21 is arranged along the periphery of the polyethylene film sheet, and the second heat-sealing part 22 is located on both sides of a diagonal line of the polyethylene film sheet. Figure 2 As shown, a nozzle 3 is heat-sealed at the rear of the bag body 1, and the nozzle 3 is connected to the inner cavity of the bag body 1; a disc 4 is also heat-sealed on the bag body 1, and the disc 4 is located in the enclosed area of ​​the first heat-sealing part 21 and the second heat-sealing part 22. A rib 41 is provided on the top wall of the disc 4, and a connecting hole is formed between the rib 41 and the disc, or a connecting hole is opened on the rib 41.

[0037] When in use, a drawstring is passed through the connection hole of the disc, and the liner liquid bag is inserted into the tank body through the air-raid hole of the tank body, with the other end of the drawstring reserved outside the air-raid hole. The staff enters the tank body through the air-raid hole, and inserts the outer flange of the nozzle out of the valve port of the tank body, so that the outer flange of the nozzle is stuck outside the valve port, and the front end of the bag body is laid to the front end of the tank body, and the rear end is laid to the rear end of the tank body. Then the liner liquid bag can be filled through the nozzle. When unloading, open the valve and unload the material outward through the nozzle. During the unloading process, the bag body can be pulled by the drawstring to make the materials on both sides of the bag body gather toward the nozzle, so as to unload more fully.

[0038] Embodiment 2 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 62%, and the mixing temperature of the first mixture is 280°C.

[0039] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 78%, the mass proportion of high-density polyethylene in the second mixture is 17%, the mass proportion of polyolefin elastomer in the second mixture is 5%, and the mixing temperature of the second mixture is 300°C.

[0040] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 6%, the mass proportion of high-density polyethylene in the third mixture is 3%, the mass proportion of metallocene polyethylene in the third mixture is 3%, the mass proportion of polyolefin elastomer in the third mixture is 0.7%, and the granulation temperature of the third mixture is 200°C.

[0041] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 2%, the mass proportion of high-density polyethylene in the fourth mixture is 7.5%, the mass proportion of metallocene polyethylene in the fourth mixture is 6%, the mass proportion of polyolefin elastomer in the fourth mixture is 3%, and the granulation temperature of the fourth mixture is 200°C.

[0042] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 4%, the mass proportion of high-density polyethylene in the fifth mixture is 3%, the mass proportion of metallocene polyethylene in the fifth mixture is 25%, the mass proportion of polyolefin elastomer in the fifth mixture is 5.6%, and the granulation temperature of the fifth mixture is 200°C.

[0043] In step (6), the extrusion temperature of the multilayer co-extrusion is 190° C., the thickness of the outer film is 125 μm, and the thickness of the inner film is 140 μm.

[0044] The rest is the same as in Example 1.

[0045] Embodiment 3 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 60%, and the mixing temperature of the first mixture is 250°C.

[0046] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 75%, the mass proportion of high-density polyethylene in the second mixture is 20%, the mass proportion of polyolefin elastomer in the second mixture is 5%, and the mixing temperature of the second mixture is 280°C.

[0047] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 8%, the mass proportion of high-density polyethylene in the third mixture is 2%, the mass proportion of metallocene polyethylene in the third mixture is 2%, the mass proportion of polyolefin elastomer in the third mixture is 1%, and the granulation temperature of the third mixture is 190°C.

[0048] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 3%, the mass proportion of high-density polyethylene in the fourth mixture is 6%, the mass proportion of metallocene polyethylene in the fourth mixture is 8%, the mass proportion of polyolefin elastomer in the fourth mixture is 4%, and the granulation temperature of the fourth mixture is 190°C.

[0049] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 3%, the mass proportion of high-density polyethylene in the fifth mixture is 4%, the mass proportion of metallocene polyethylene in the fifth mixture is 20%, the mass proportion of polyolefin elastomer in the fifth mixture is 5%, and the granulation temperature of the fifth mixture is 190°C.

[0050] In step (6), the extrusion temperature of the multilayer co-extrusion is 180°C, the thickness of the outer film is 115 μm, and the thickness of the inner film is 150 μm.

[0051] The rest is the same as in Example 1.

[0052] Embodiment 4 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 59%, and the mixing temperature of the first mixture is 230°C.

[0053] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 77%, the mass proportion of high-density polyethylene in the second mixture is 19%, the mass proportion of polyolefin elastomer in the second mixture is 4%, and the mixing temperature of the second mixture is 270°C.

[0054] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 9%, the mass proportion of high-density polyethylene in the third mixture is 2%, the mass proportion of metallocene polyethylene in the third mixture is 1.7%, the mass proportion of polyolefin elastomer in the third mixture is 1.3%, and the granulation temperature of the third mixture is 180°C.

[0055] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 4%, the mass proportion of high-density polyethylene in the fourth mixture is 5%, the mass proportion of metallocene polyethylene in the fourth mixture is 9%, the mass proportion of polyolefin elastomer in the fourth mixture is 3%, and the granulation temperature of the fourth mixture is 200°C.

[0056] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 4%, the mass proportion of high-density polyethylene in the fifth mixture is 5%, the mass proportion of metallocene polyethylene in the fifth mixture is 15%, the mass proportion of polyolefin elastomer in the fifth mixture is 6%, and the granulation temperature of the fifth mixture is 180°C.

[0057] In step (6), the extrusion temperature of the multilayer co-extrusion is 190° C., the thickness of the outer film is 105 μm, and the thickness of the inner film is 140 μm.

[0058] The rest is the same as in Example 1.

[0059] Embodiment 5 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 61%, and the mixing temperature of the first mixture is 260°C.

[0060] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 73%, the mass proportion of high-density polyethylene in the second mixture is 21%, the mass proportion of polyolefin elastomer in the second mixture is 6%, and the mixing temperature of the second mixture is 290°C.

[0061] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 7%, the mass proportion of high-density polyethylene in the third mixture is 3%, the mass proportion of metallocene polyethylene in the third mixture is 1.5%, the mass proportion of polyolefin elastomer in the third mixture is 1%, and the granulation temperature of the third mixture is 200°C.

[0062] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 2%, the mass proportion of high-density polyethylene in the fourth mixture is 6%, the mass proportion of metallocene polyethylene in the fourth mixture is 10%, the mass proportion of polyolefin elastomer in the fourth mixture is 4%, and the granulation temperature of the fourth mixture is 180°C.

[0063] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 2%, the mass proportion of high-density polyethylene in the fifth mixture is 3%, the mass proportion of metallocene polyethylene in the fifth mixture is 22%, the mass proportion of polyolefin elastomer in the fifth mixture is 4%, and the granulation temperature of the fifth mixture is 200°C.

[0064] In step (6), the extrusion temperature of the multilayer co-extrusion is 170°C, the thickness of the outer film is 125 μm, and the thickness of the inner film is 160 μm.

[0065] The rest is the same as in Example 1.

[0066] Embodiment 6 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 60%, and the mixing temperature of the first mixture is 240°C.

[0067] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 74%, the mass proportion of high-density polyethylene in the second mixture is 22%, the mass proportion of polyolefin elastomer in the second mixture is 4%, and the mixing temperature of the second mixture is 280°C.

[0068] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 9%, the mass proportion of high-density polyethylene in the third mixture is 2%, the mass proportion of metallocene polyethylene in the third mixture is 2.3%, the mass proportion of polyolefin elastomer in the third mixture is 1.2%, and the granulation temperature of the third mixture is 190°C.

[0069] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 2.5%, the mass proportion of high-density polyethylene in the fourth mixture is 6.5%, the mass proportion of metallocene polyethylene in the fourth mixture is 7%, the mass proportion of polyolefin elastomer in the fourth mixture is 5%, and the granulation temperature of the fourth mixture is 180°C.

[0070] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 3%, the mass proportion of high-density polyethylene in the fifth mixture is 4%, the mass proportion of metallocene polyethylene in the fifth mixture is 17%, the mass proportion of polyolefin elastomer in the fifth mixture is 5%, and the granulation temperature of the fifth mixture is 200°C.

[0071] In step (6), the extrusion temperature of the multi-layer co-extrusion is 180° C., the thickness of the outer film is 120 μm, and the thickness of the inner film is 145 μm.

[0072] The rest is the same as in Example 1.

[0073] Embodiment 7 The difference between this embodiment and the first embodiment is that: In step (1), the mass percentage of linear low-density polyethylene in the first mixture is 59%, and the mixing temperature of the first mixture is 270°C.

[0074] In step (2), the mass proportion of linear low-density polyethylene in the second mixture is 77%, the mass proportion of high-density polyethylene in the second mixture is 17%, the mass proportion of polyolefin elastomer in the second mixture is 6%, and the mixing temperature of the second mixture is 280°C.

[0075] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 8%, the mass proportion of high-density polyethylene in the third mixture is 1%, the mass proportion of metallocene polyethylene in the third mixture is 2.6%, the mass proportion of polyolefin elastomer in the third mixture is 0.9%, and the granulation temperature of the third mixture is 180°C.

[0076] In step (4), the mass proportion of linear low-density polyethylene in the fourth mixture is 3.5%, the mass proportion of high-density polyethylene in the fourth mixture is 5.5%, the mass proportion of metallocene polyethylene in the fourth mixture is 8%, the mass proportion of polyolefin elastomer in the fourth mixture is 4%, and the granulation temperature of the fourth mixture is 190°C.

[0077] In step (5), the mass proportion of linear low-density polyethylene in the fifth mixture is 2%, the mass proportion of high-density polyethylene in the fifth mixture is 4%, the mass proportion of metallocene polyethylene in the fifth mixture is 23%, the mass proportion of polyolefin elastomer in the fifth mixture is 4%, and the granulation temperature of the fifth mixture is 180°C.

[0078] In step (6), the extrusion temperature of the multilayer co-extrusion is 190° C., the thickness of the outer film is 110 μm, and the thickness of the inner film is 155 μm.

[0079] The rest is the same as in Example 1.

[0080] Comparative Example The difference between this comparative example and Example 1 is that: In step (1), a nozzle is prepared using high-density polyethylene.

[0081] In step (2), a disc is prepared using high-density polyethylene.

[0082] In step (3), the mass proportion of linear low-density polyethylene in the third mixture is 45%, the mass proportion of high-density polyethylene in the third mixture is 15%, the mass proportion of metallocene polyethylene in the third mixture is 30%, and the mass proportion of polyolefin elastomer in the third mixture is 10%.

[0083] In step (6), the first special material obtained in step (3) is placed in each silo of a five-layer co-extruder, and is blown through multi-layer co-extrusion to form a five-layer polyethylene film arranged from outside to inside, each layer of which has the same material.

[0084] The rest is the same as in Example 1. That is, step (4) and step (5) in Example 1 are omitted, and each layer is prepared using step (3) to obtain the special material.

[0085] The outer films prepared in the above-mentioned embodiments and comparative examples were subjected to performance tests in terms of tensile strength, tear strength, drop impact, elongation and heat seal strength, the Shore hardness of the nozzle and the Shore hardness of the disc. Among them, the tensile strength test was conducted in accordance with the ASTM standard "D882-02 Test method for tensile properties of plastic thin sheets", the tear strength test was conducted in accordance with the ASTM standard "D1004-13 American Standards for Materials and Testing", the flat dart impact test was conducted in accordance with the national standard "GB / T9639.1-2008 Test method for impact resistance of plastic films and sheets - free-falling dart method", the heat seal strength was conducted in accordance with the industry standard "QB / T 2358-1998 Test method for heat seal strength of plastic film packaging bags", and the Shore hardness test was conducted in accordance with the national standard "GB / T531-1999 Test method for indentation hardness of rubber pocket hardness meter". The test results are as follows:

[0086] It can be seen that the polyethylene film prepared by the present invention has excellent physical properties and higher heat-sealing strength, and is more suitable for liquid packaging. In use, the nozzle can not only be supported on the valve port of the tank truck, but also easily pass through the valve port after deformation. The nozzle and the disc do not reduce the heat-sealing strength between them and the bag body, but depend on the heat-sealing strength of the polyethylene film, making the liner bag more durable.

[0087] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. An ISO tank truck liner liquid bag, comprising a bag body, wherein the bag body is formed by heat-sealing a polyethylene film, and a heat-sealing line is formed at the heat-sealing position, and the characteristics are: The rear part of the bag body is heat-sealed with a nozzle, which is connected to the inner cavity of the bag body, and is characterized in that: the nozzle is made of linear low-density polyethylene with a mass percentage of 58-62% and high-density polyethylene as the balance; The bag body is also heat-sealed with a disc, the top wall of the disc is provided with a convex rib, a connecting hole is formed between the convex rib and the disc or a connecting hole is opened on the convex rib, and the disc is made of the following raw materials in percentage by mass: Linear low density polyethylene 71~78% High-density polyethylene 17-23% Polyolefin elastomer 4-6%.

2. The ISO tank truck liner liquid bag according to claim 1, characterized in that: The polyethylene film is rhombus-shaped, and the heat sealing line is divided into a first heat sealing portion and a second heat sealing portion connected to the first heat sealing portion. The first heat sealing portion is arranged along the periphery of the polyethylene film, and the second heat sealing portion is located on both sides of a diagonal line of the polyethylene film. The disc is located in the enclosed area of ​​the first heat sealing portion and the second heat sealing portion.

3. The ISO tank truck liner fluid bag according to claim 2, characterized in that: The polyethylene film is formed by overlapping an inner film and an outer film, the thickness of the outer film is 105-125 μm, and the thickness of the inner film is 140-160 μm.

4. The ISO tank truck liner liquid bag according to any one of claims 1 to 3, characterized in that: The inner film and the outer film are composed of an outermost layer, a second outer layer, a middle layer, a second inner layer and an innermost layer arranged in sequence from the outside to the inside; the outermost layer and the innermost layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 6~10% High-density polyethylene 1~3% Metallocene polyethylene 1~3% Polyolefin elastomer 0.7~1.3% The sub-outer layer and the sub-inner layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 2~4% High-density polyethylene 4.5~7.5% Metallocene polyethylene 6~10% Polyolefin elastomer 3~5% The middle layer is made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 2~4% High density polyethylene 3~5% Metallocene polyethylene 15~25% Polyolefin elastomer 4-6%.

5. The ISO tank truck liner fluid bag according to claim 4, characterized in that: The outermost layer and the innermost layer are both made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 8% High density polyethylene 2% Metallocene polyethylene 2% Polyolefin elastomer 1% The sub-outer layer and the sub-inner layer are made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 3% High density polyethylene 6% Metallocene polyethylene 8% Polyolefin elastomer 4% The middle layer is made of the following raw materials accounting for the total mass percentage of the polyethylene film: Linear low density polyethylene 3% High density polyethylene 4% Metallocene polyethylene 20% Polyolefin elastomer 5%.

6. The ISO tank truck liner liquid bag according to any one of claims 1 to 3, characterized in that: The nozzle is made of the following raw materials in percentage by mass: Linear low density polyethylene 60% High density polyethylene 40%.

7. The ISO tank truck liner fluid bag according to any one of claims 1 to 3, characterized in that: The disc is made of the following raw materials in percentage by mass: Linear low density polyethylene 75 % High density polyethylene 20% Polyolefin elastomer 5%.

8. A method for preparing an ISO tank truck liner liquid bag, comprising the following steps: (1) Preparing a nozzle: mixing linear low-density polyethylene and high-density polyethylene into a first mixture, wherein the linear low-density polyethylene accounts for 58-62% by weight of the first mixture and the remainder is high-density polyethylene, and the first mixture is kneaded and molded to obtain a nozzle; (2) Preparing a disc: mixing linear low-density polyethylene, high-density polyethylene and polyolefin elastomer into a second mixture, wherein the mass proportion of the linear low-density polyethylene in the second mixture is 71-78%, the mass proportion of the high-density polyethylene in the second mixture is 17-23%, and the mass proportion of the polyolefin elastomer in the second mixture is 4-6%. The second mixture is kneaded and then compression molded to obtain a disc having a rib on the top wall, wherein a connecting hole is enclosed between the rib and the top wall of the disc or a connecting hole is opened on the rib; (3) Preparing a first special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a third mixed material, and granulating the third mixed material to obtain the first special material; the mass proportion of linear low-density polyethylene in the third mixed material is 6-10%, the mass proportion of high-density polyethylene in the third mixed material is 1-3%, the mass proportion of metallocene polyethylene in the third mixed material is 1-3%, and the mass proportion of polyolefin elastomer in the third mixed material is 0.7-1.3%; (4) Preparing a second special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a fourth mixed material, and granulating the fourth mixed material to obtain the second special material; the mass proportion of linear low-density polyethylene in the fourth mixed material is 2-4%, the mass proportion of high-density polyethylene in the fourth mixed material is 4.5-7.5%, the mass proportion of metallocene polyethylene in the fourth mixed material is 6-10%, and the mass proportion of polyolefin elastomer in the fourth mixed material is 3-5%; (5) Preparing the third special material: mixing linear low-density polyethylene, high-density polyethylene, metallocene polyethylene and polyolefin elastomer into a fifth mixed material, and granulating the fifth mixed material to obtain the third special material; the mass proportion of linear low-density polyethylene in the fifth mixed material is 2-4%, the mass proportion of high-density polyethylene in the fifth mixed material is 3-5%, the mass proportion of metallocene polyethylene in the fifth mixed material is 15-25%, and the mass proportion of polyolefin elastomer in the fifth mixed material is 4-6%; (6) Preparing a polyethylene film: the first special material prepared in step (3), the second special material prepared in step (4), the third special material prepared in step (5), the second special material prepared in step (4), and the first special material prepared in step (3) are sequentially subjected to multi-layer co-extrusion blow molding to form a polyethylene film having an outermost layer, a second outermost layer, a middle layer, a second innermost layer, and a third innermost layer arranged from the outside to the inside; (7) Bag making: The polyethylene film obtained in step (6) is heat-sealed to form a bag body, and a heat-sealed line is formed at the heat-sealed part; (8) Configuring accessories: Heat-sealing the nozzle prepared in step (1) and the disc prepared in step (2) onto the bag body prepared in step (7), with the nozzle being located at the rear of the bottom wall of the bag body and the disc being located on both sides of the top wall of the bag body.

9. The method for preparing the ISO tank truck liner liquid bag according to claim 8, characterized in that: The heat sealing line of step (7) includes a first heat sealing portion and a second heat sealing portion connected to the first heat sealing portion, the first heat sealing portion is arranged along the periphery of the polyethylene film, the second heat sealing portion is located on both sides of a diagonal line of the polyethylene film, and the disk is located in the enclosed area of ​​the first heat sealing portion and the second heat sealing portion.

10. The method for preparing the ISO tank truck liner liquid bag according to claim 8 or 9, characterized in that: The inner film and the outer film are successively prepared in step (6), and the inner film and the outer film are overlapped to form a polyethylene film sheet.

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