Manual pre-stretching wrapping film and production method thereof

Abstract

The invention belongs to the technical field of packaging tools, and particularly relates to a manual pre-stretching wrapping film and a production method thereof.The manual pre-stretching wrapping film comprises a film body and a winding drum, and the film body is driven by a plurality of stretching rollers to be pre-stretched. The film body is made of a mixture of metallocene polyethylene, linear polyethylene and tackifying master batch. The stretch rate of the film body which is subjected to plastic deformation caused by pre-stretching is 300%-450%, and the thickness of the film body is 10-15 microns. According to the manual pre-stretching wrapping film, pre-stretching is conducted through equipment before the wrapping film leaves a factory and is sold, the problems of poor consistency, insufficient stretching rate and material waste during manual stretching are solved, and therefore more cost is saved. And displacement and scattering of the cargoes caused by insufficient fastening performance of the cargoes due to continuous extension of the wrapping film which is not stretched in place in the transportation process during transportation of the cargoes can also be avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of packaging tools, and particularly relates to a hand pre-stretching wrapping film and a production method thereof. BACKGROUND

[0002] The wrapping film, also known as stretch film or shrink film, is a transparent and elastic plastic film usually made of linear low-density polyethylene (LLDPE). Its main features include strong stretchability, adhesion, transparency and puncture resistance, which make it widely used in packaging and transportation. The wrapping film includes machine wrapping film and hand wrapping film. The machine wrapping film is used for automatic packaging lines and is suitable for large-scale industrial packaging with high efficiency. The hand wrapping film is suitable for small-scale packaging and retail packaging and is flexible to operate. The working process of the hand wrapping film is generally used for pallet packaging, which tightly wraps the products on the pallet to provide stability and prevent the goods from shifting, scattering or being damaged during transportation. It can effectively protect the products and reduce losses.

[0003] The current hand wrapping film is mainly held vertically by both hands of the operator, and the wrapping film is stretched by a large force to produce plastic deformation after overcoming the yield strength, with a general stretch rate of 150%-300%, so as to ensure that the deformed wrapping film tightly adheres to the goods during wrapping and provides good fixing effect. In the use process, the following problems need to be improved: 1. Since the plastic deformation of the wrapping film needs to be achieved by an appropriate pulling force, the physical strength of the operator is consumed, and accordingly, it is difficult to achieve the wrapping speed of the machine wrapping film. Small-scale packaging and retail packaging are not convenient to use machine stretching, resulting in low work efficiency.

[0004] 2. In the actual operation process, the operation level of each operator is different, and some operators do not have enough strength or are lazy, which leads to insufficient stretch rate and does not reach the ideal stretching length, resulting in the use of more wrapping film to wrap the same goods, which increases the amount of material used; and some operators use too much force, which may cause damage to the wrapping film. Both of these two cases lead to cost increase.

[0005] 3. If the operation is not in place, the wrapping film does not reach the appropriate stretch rate during use, and the plastic deformation of the film is insufficient. During transportation, the wrapping film may continue to extend and elongate with vibration and movement, and the wrapping film has insufficient tightening effect. Such looseness may cause the goods to shift and scatter, especially in long-distance transportation or poor road conditions. This situation not only causes damage to the goods, but also may increase safety hazards. SUMMARY

[0006] To address the aforementioned shortcomings of existing technologies, this invention aims to solve the problem that conventional stretch film requires significant manual labor for stretching during use. Inadequate stretching can lead to damage or waste of the film. Furthermore, insufficiently stretched film can cause goods to shift or scatter during transport due to continued elongation. This invention provides a hand-held pre-stretched stretch film and its production method. By pre-stretching the film before shipment, it avoids inconsistent packaging, saves labor, and reduces transportation risks.

[0007] To achieve the above objectives, the present invention provides a hand-operated pre-stretched wrapping film, comprising a film body and a roll, wherein the film body is pre-stretched by being driven by multiple stretching rollers. The membrane material is a mixture of metallocene polyethylene, linear polyethylene, and thickening masterbatch. The pre-stretched membrane undergoes plastic deformation with a tensile rate of 300%–450%. The thickness of the membrane is 10-15 μm.

[0008] According to another embodiment of the present invention or any of the foregoing embodiments, the winding film is a paper tube, the length of which exceeds the width of the film by 2-12 cm.

[0009] According to another embodiment of the present invention or any of the foregoing embodiments, the winding film is a plastic tube, and the length of the plastic tube exceeds the width of the film by more than 20 cm.

[0010] According to another embodiment of the present invention or any of the foregoing embodiments, the stretching roller is driven by gears with different speed ratios.

[0011] According to another embodiment of the present invention or any of the foregoing embodiments, the width of the wrapping film is 35-45 cm.

[0012] According to another embodiment of the present invention or any of the foregoing embodiments, the tensile force borne by the film body exceeds the yield strength of the material but is lower than the breaking strength.

[0013] The beneficial effects of this invention are: The hand-held pre-stretched wrapping film of this invention is pre-stretched by equipment before being shipped to the market, avoiding the problems of inconsistent stretching and insufficient stretching rate that occur during manual stretching, thus saving materials and reducing costs. It also prevents goods from shifting or scattering due to insufficient securing of the wrapping film during transportation, which could result from the wrapping film not being fully stretched. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the pre-stretched wrapping film for hand use according to the present invention during use; Figure 2 This is a three-dimensional schematic diagram of the paper tube type hand-held pre-stretched wrapping film described in this invention; Figure 3 This is a three-dimensional schematic diagram of the plastic tubular pre-stretched wrapping film for hand use according to the present invention; In the diagram: 1. Membrane body; 2. Paper tube; 3. Film pulling rod; 4. Plastic tube. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0016] like Figure 1 , 2 As shown, a hand-operated pre-stretch wrapping film includes a film body 1 and a roll. The film body 1 is pre-stretched by multiple stretching rollers driven by gears with different speed ratios. The tensile force borne by the film body 1 exceeds the yield strength of the material but is lower than its breaking strength.

[0017] The material of membrane 1 is a mixture of metallocene polyethylene, linear polyethylene, and thickening masterbatch.

[0018] The elongation rate of the membrane 1, which undergoes plastic deformation under pre-stretching, is 300%–450%.

[0019] The thickness of membrane 1 is 10-15 μm, and the width of membrane 1 is 35-45 cm.

[0020] like Figure 2 As shown, the roll is a paper tube 2, and the length of the paper tube 2 exceeds the width of the film body 1 by 2-12cm. It is generally used in conjunction with a traditional paper tube film pulling rod 3. Example

[0021] Other features are the same as in Embodiment 1, except for the arrangement of the roll. Figure 3 As shown, the roll is a plastic tube 4, and the length of the plastic tube 4 exceeds the width of the membrane body 1 by more than 20cm.

[0022] Working principle of the invention: It should be pointed out that the "pre-stretching" concept mentioned in the present application is different from the pre-stretching film in the industry. The pre-stretching film in the industry refers to pre-stretching the film before use. The pre-stretching of the present application refers to pre-stretching the wrapping film to overcome the yield strength and enter the plastic deformation before the wrapping film leaves the factory. That is, the main difference between the product involved in the present application and the existing product is that the existing product does not undergo plastic deformation, and it can be stretched by more than 3 times in length. The existing wrapping film has a width of about 50 cm and a thickness of 22-30 um, and needs to be stretched by force after being wrapped on the packaging to be wrapped to produce plastic deformation.

[0023] The present application, however, creatively stretches the wrapping film by a plurality of rollers before leaving the factory, i.e. by gear drives with different speed ratios, to a thickness of 10-15 um, usually 12 um. Compared with stretching by different operators, the stretching force is greater, more consistent, and the stretching effect is better, which can maximize the stretching rate without breaking the wrapping film at the breaking strength. Because of the higher stretching rate, it is more material-saving and does not waste materials. Because the space for plastic deformation is very small, only slight stretching is needed during use, even by a female worker with less strength. At the same time, when the goods are transported, because there is no plastic deformation, the goods can be considered to be wrapped, ensuring the integrity and safety of the goods during transportation, and avoiding displacement or scattering.

[0024] The main advantages of the present application are that the wrapping film of the present application has sufficient tension after pre-stretching, and does not need to apply excessive tension during use, which can more easily complete the packaging work and save more physical strength. The physical strength consumption of the operator is greatly reduced, especially in long-term or large-scale packaging operations. The operation is simpler and faster, which can improve the overall packaging efficiency and is suitable for situations that require quick packaging tasks. The pre-stretched wrapping film usually wraps the goods more tightly, reduces waste, and improves the use efficiency of the packaging material.

[0025] The principle of stretching of the hand pre-stretched wrapping film of the present application is mainly based on the elastic and plastic deformation characteristics of the material. The wrapping film of the present application is made of linear low-density polyethylene (LLDPE), metallocene polyethylene, and tackifying masterbatch. This material has good tensile strength and ductility. The material is composed of long-chain polymer molecules. In the unstretched state, these molecular chains exist in a relatively disordered state with certain crystalline regions and amorphous regions. When the wrapping film is subjected to tensile stress, the intermolecular forces (such as van der Waals forces) between the polymer molecular chains are overcome, and the molecular chains begin to align along the direction of stretching. This process is first an elastic deformation, i.e. the molecular chains are lengthened but can recover to the original state. When the tension continues to increase and exceeds the elastic limit of the material, irreversible rearrangement of the molecular chains occurs, and the crystalline regions are partially deconstructed, and more amorphous regions are lengthened. This makes the wrapping film unable to completely recover to the original shape after the external force is removed, retaining a part of the shape after stretching. This plastic deformation enables the wrapping film to closely adhere to the packaged objects during use, providing sustained tension and stability. Although the tension is removed, part of the molecular chains of the film have been fixed in the stretched state, so the film can maintain the shape after stretching.

[0026] The stretched film of the present application is pre-stretched by 300%-450%, i.e. 1 meter of wrapping film can be stretched to 3-4.5 meters. During the stretching process, the molecular chains of the wrapping film are lengthened, making it have stronger tension and retraction force, and being able to more closely wrap the objects and provide stability. In the early stage of stretching, the wrapping film will be lengthened within the elastic range, and even if the tension disappears, it can still recover to the original shape. This elastic deformation mainly provides preliminary tension. When a greater tension is applied, the molecular chains of the wrapping film are permanently stretched, and this plastic deformation makes the wrapping film maintain a certain ductility after stretching, i.e. even if the tension disappears, it will not completely recover to the original shape. This part of the ductility helps the film to more closely wrap the objects. After the wrapping film is stretched, it will generate a retraction force, helping it to closely adhere to the packaging object and providing a stable packaging effect.

[0027] The present application uses a plastic tube 4 as the winding drum of the wrapping film body 1. The operator can directly hold the outer wall of the lengthened and smooth plastic tube 4 during use, which is very labor-saving for packaging. The traditional wrapping film uses a rough paper tube 2, which can only hold the end face and inner wall of the paper tube 2, and the operation is laborious and requires wearing gloves. The traditional wrapping film generally requires special wrapping tools or a film pulling rod 3 passing through the paper tube 2 for assistance, and the film pulling rod 3 or handle tool needs to be specially stored, which is not convenient to use.

[0028] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments are only for illustrating the technical concepts and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A hand-held pre-stretch wrapping film, comprising a film body (1) and a roll, characterized in that: The membrane (1) is pre-stretched by multiple stretching rollers. The material of the membrane (1) is a mixture of metallocene polyethylene, linear polyethylene, and thickening masterbatch. The membrane (1) undergoes plastic deformation under pre-stretching with a tensile rate of 300%–450%. The thickness of the membrane (1) is 10-15 μm. The width of the membrane (1) is 35-45cm.

2. The hand-held pre-stretch wrapping film according to claim 1, characterized in that: The roll is a paper tube (2), and the length of the paper tube (2) exceeds the width of the film (1) by 2-12 cm.

3. The hand-held pre-stretch wrapping film according to claim 1, characterized in that: The roll is a plastic tube (4), and the length of the plastic tube (4) exceeds the width of the membrane (1) by more than 20 cm.

4. The hand-held pre-stretch wrapping film according to claim 1, characterized in that: The stretching rollers are driven by gears with different speed ratios.

5. A hand-held pre-stretch wrapping film according to claim 1, characterized in that: The tensile force borne by the membrane (1) exceeds the yield strength of the material but is lower than the fracture strength.

6. A method for producing a hand-held pre-stretch wrapping film according to any one of claims 1-5, characterized in that: Before leaving the factory, the hand-held pre-stretched wrapping film is pre-stretched by multiple stretching rollers with a pre-stretch ratio of 300%-450%. The molecular chains of the wrapping film are permanently stretched. This plastic deformation allows the wrapping film to maintain a certain degree of extensibility after stretching, and it will not completely return to its original shape even if the tension is removed.

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