Easily-uncovered film, preparation method thereof and application of easily-uncovered film in medical reagent tube

Abstract

The invention relates to the technical field of composite membranes, and provides an easy-to-uncover membrane, a preparation method thereof and an application of the easy-to-uncover membrane in a medical reagent tube. The easy-to-uncover film comprises an outer layer, a middle layer and an inner layer, the outer layer is prepared from low-density polyethylene and linear low-density polyethylene, and the middle layer is prepared from low-density polyethylene, linear low-density polyethylene and metallocene medium-density polyethylene. The preparation raw materials of the inner layer comprise low-density polyethylene, metallocene polyethylene and a POE (Polyolefin Elastomer). The metallocene medium-density polyethylene is added into the middle layer of the easy-to-tear film, so that the heat sealing strength of the film can be adjusted, and the phenomenon of sealing caused by too high heat sealing strength is avoided; the POE elastomer is added into the inner layer, so that the easy stripping property of the film can be improved, and the phenomena of wiredrawing, layering and the like during uncovering are avoided. In conclusion, the easy-to-uncover film provided by the invention not only can effectively seal the medical reagent tube, but also is not easy to wiredraw and layer when being uncovered, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of composite films, in particular to an easy-to-peel film and a preparation method thereof and application in a medical reagent tube. Background Art

[0002] Medical reagent tubes are widely used in medical and laboratory environments, mainly for holding various medical reagents and biological samples. The cover film of the medical reagent tube can seal the reagent tube to prevent the volatilization and leakage of the reagent, and prevent the outside air, moisture, dust, etc. from entering and contaminating the reagent, thus protecting the stability of the reagent.

[0003] However, when the current medical reagent tube cover film is used to seal the reagent tube, the sealing strength is likely to be relatively high, and the cover film and the reagent tube are tightly combined, making it difficult to remove during use. If the heat sealing strength is reduced, the cover film and the reagent tube are likely to stick together, and when removed, wire drawing and delamination are likely to occur, leaving residues on the reagent tube, which can easily contaminate the reagent during use. Summary of the invention

[0004] In view of this, the present invention provides an easy-to-peel film and a preparation method thereof and an application in a medical reagent tube. The easy-to-peel film provided by the present invention can effectively seal the medical reagent tube, has moderate heat-sealing strength, is easy to peel off, does not cause wire drawing, delamination, etc. when peeling off, and does not leave residue at the mouth of the reagent tube.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] An easy-to-peel film comprises an outer layer, a middle layer and an inner layer;

[0007] In terms of weight, the raw materials for preparing the outer layer include: 10 to 40 parts of low-density polyethylene and 30 to 80 parts of linear low-density polyethylene;

[0008] The raw materials for preparing the middle layer include, by weight: 10 to 40 parts of low-density polyethylene, 20 to 60 parts of linear low-density polyethylene, and 30 to 80 parts of metallocene medium-density polyethylene;

[0009] Calculated by weight, the raw materials for preparing the inner layer include: 20 to 80 parts of low-density polyethylene, 20 to 80 parts of metallocene polyethylene, and 10 to 30 parts of POE elastomer.

[0010] Preferably, the melt index of the low-density polyethylene used in the outer layer and the middle layer is independently 1.5-2.5 g / 10 min, and the density is independently 0.92-0.93 g / cm 3The outer layer and the middle layer use linear low-density polyethylene with a melt index of 1.5 to 2.5 g / 10 min and a density of 0.915 to 0.925 g / cm 3 .

[0011] Preferably, the metallocene medium density polyethylene used in the middle layer has a melt index of 0.2-1 g / 10 min and a density of 0.93-0.94 g / cm 3 .

[0012] Preferably, the low-density polyethylene used in the inner layer has a melt index of 1.5-2.5 g / 10 min and a density of 0.92-0.93 g / cm 3 The metallocene polyethylene used in the inner layer has a melt index of 1.5 to 2.5 g / 10 min and a density of 0.915 to 0.925 g / cm 3 ; The melt index of the POE elastomer used in the inner layer is 0.5 to 1.5 g / 10 min.

[0013] Preferably, the grade of low-density polyethylene used in the outer layer and the middle layer is 2420H; the grade of linear low-density polyethylene used in the outer layer and the middle layer is 201XV; the grade of metallocene medium-density polyethylene used in the middle layer is 3505MC.

[0014] Preferably, the brand of low-density polyethylene used in the inner layer is 2426H; the brand of metallocene polyethylene used in the inner layer is 2018MB; and the brand of POE elastomer used in the inner layer is BL3110M.

[0015] The present invention also provides a method for preparing the easy-to-peel film of the above scheme, comprising the following steps: co-extruding raw materials for preparing the outer layer, the middle layer and the inner layer to obtain the easy-to-peel film.

[0016] Preferably, the three-layer co-extrusion comprises: feeding the raw materials for the outer layer, the middle layer and the inner layer into the outer layer, the middle layer and the inner layer extruders respectively for melting and plasticizing, conveying the obtained glue solution to the die head, extruding and blowing the film to obtain a film bubble, and after the film bubble is air-cooled, passing through a stabilizing ring and a herringbone arrangement to be pulled upward for rotation, and after the film bubble is flattened, it is inspected, trimmed, destaticized and rolled to obtain the easy-to-peel film.

[0017] Preferably, the outer layer extruder, the middle layer extruder and the inner layer extruder are all provided with 5 heating zones, which are recorded as zones 1 to 5 in the order in which the raw materials pass; the temperature of zone 1 of the outer layer extruder is 150-160°C, the temperature of zone 2 is 155-165°C, the temperature of zone 3 is 155-165°C, the temperature of zone 4 is 155-165°C, and the temperature of zone 5 is 155-165°C; the temperature of zone 1 of the middle layer extruder is The temperature of zone 1 of the inner layer extruder is 160-170°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 170-180°C, the temperature of zone 4 is 170-180°C, and the temperature of zone 5 is 170-180°C; the temperature of zone 1 of the inner layer extruder is 160-170°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 170-180°C, the temperature of zone 4 is 170-180°C, and the temperature of zone 5 is 170-180°C;

[0018] The die head is provided with 4 heating zones, which are respectively recorded as zones 1 to 4 according to the order in which the raw materials pass through; the temperature of zone 1 of the die head is 170-180°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 170-180°C, and the temperature of zone 4 is 170-180°C.

[0019] The present invention also provides the use of the easy-to-peel film described in the above scheme or the easy-to-peel film prepared by the preparation method described in the above scheme in a medical reagent tube.

[0020] The present invention provides an easy-to-peel film, including an outer layer, a middle layer and an inner layer; in parts by mass, the raw materials for preparing the outer layer include: 10 to 40 parts of low-density polyethylene, 30 to 80 parts of linear low-density polyethylene; in parts by mass, the raw materials for preparing the middle layer include: 10 to 40 parts of low-density polyethylene, 20 to 60 parts of linear low-density polyethylene, 30 to 80 parts of metallocene medium-density polyethylene; in parts by mass, the raw materials for preparing the inner layer include: 20 to 80 parts of low-density polyethylene, 20 to 80 parts of metallocene polyethylene, and 10 to 30 parts of POE elastomer. The present invention adds metallocene medium-density polyethylene to the middle layer of the easy-to-peel film, which can adjust the heat-sealing strength of the film and avoid the phenomenon of sealing due to excessive heat-sealing strength. At the same time, the present invention adds POE elastomer to the inner layer, which can improve the easy peelability of the film and avoid wire drawing, delamination and other phenomena when it is opened. Therefore, the easy-to-peel film provided by the present invention can not only achieve effective sealing of medical reagent tubes, have moderate heat-sealing strength, but also be easy to peel off, not prone to wire drawing or delamination when peeled off, and will not leave residue at the mouth of the reagent tube, and has broad application prospects. DETAILED DESCRIPTION

[0021] The present invention provides an easy-to-peel film, comprising an outer layer, a middle layer and an inner layer;

[0022] In terms of weight, the raw materials for preparing the outer layer include: 10 to 40 parts of low-density polyethylene and 30 to 80 parts of linear low-density polyethylene;

[0023] The raw materials for preparing the middle layer include, by weight: 10 to 40 parts of low-density polyethylene, 20 to 60 parts of linear low-density polyethylene, and 30 to 80 parts of metallocene medium-density polyethylene;

[0024] Calculated by weight, the raw materials for preparing the inner layer include: 20 to 80 parts of low-density polyethylene, 20 to 80 parts of metallocene polyethylene, and 10 to 30 parts of POE elastomer.

[0025] Unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0026] In terms of mass fraction, the raw material for preparing the outer layer includes 10 to 40 parts of low-density polyethylene, specifically 10 parts, 20 parts, 25 parts or 30 parts; the melt index of the low-density polyethylene used in the outer layer is preferably 1.5 to 2.5 g / 10 min, more preferably 2 to 2.5 g / 10 min, and the density is preferably 0.92 to 0.93 g / cm 3 , more preferably 0.924 to 0.925 g / cm 3 In a specific embodiment of the present invention, the outer layer uses a low-density polyethylene grade of 2420H, which is produced by CNOOC Shell, has a melt index of 2g / 10min and a density of 0.924g / cm 3 The low-density polyethylene used in the present invention has the characteristics of high cleanliness, good die-cutting and easy processing.

[0027] Based on the mass fraction of low-density polyethylene used in the outer layer, the raw material for preparing the outer layer includes 30 to 80 parts of linear low-density polyethylene, specifically 70 parts, 75 parts or 80 parts; the melt index of the linear low-density polyethylene is preferably 1.5 to 2.5 g / 10min, more preferably 2 g / 10min, and the density is preferably 0.915 to 0.925 g / cm 3 , more preferably 0.915 to 0.918 g / cm 3 In a specific embodiment of the present invention, the grade of the linear medium density polyethylene is 201XV, its manufacturer is Exxon, the melt index is 2g / 10min, and the density is 0.918g / cm 3 The linear low-density polyethylene used in the present invention has good compatibility and good processability.

[0028] In terms of mass percentage, the raw materials for preparing the middle layer include 10 to 40 parts of low-density polyethylene, specifically 10 parts, 20 parts or 30 parts; the melt index, density and grade of the low-density polyethylene used in the middle layer are consistent with those of the low-density polyethylene used in the outer layer, which will not be repeated here.

[0029] Based on the mass fraction of the low-density polyethylene used in the middle layer, the raw material for preparing the middle layer includes 20 to 60 parts of linear low-density polyethylene, specifically 30 parts, 40 parts or 50 parts; the melt index, density and grade of the linear low-density polyethylene used in the middle layer are consistent with those of the linear low-density polyethylene used in the outer layer, and will not be repeated here.

[0030] Based on the mass fraction of low-density polyethylene used in the middle layer, the raw material for preparing the middle layer includes 30 to 80 parts of metallocene medium-density polyethylene, specifically 40 parts, 50 parts or 60 parts; the metallocene medium-density polyethylene is preferably ethylene 1-hexene copolymer; the melt index of the metallocene medium-density polyethylene is preferably 0.2 to 1 g / 10min, more preferably 0.5 to 1 g / 10min, and the density is preferably 0.93 to 0.94 g / cm 3 , more preferably 0.935 to 0.94 g / cm 3 In a specific embodiment of the present invention, the metallocene medium density polyethylene is 3505MC, which is an ethylene 1-hexene copolymer, manufactured by Exxon, with a melt index of 0.5g / 10min and a density of 0.935g / cm 3 The metallocene medium density polyethylene used in the present invention has good adhesion and stiffness.

[0031] In terms of mass fraction, the raw material for preparing the inner layer includes 20 to 80 parts of low-density polyethylene, specifically 30 parts, 40 parts, 50 parts or 60 parts; the melt index of the low-density polyethylene used in the inner layer is preferably 1.5 to 2.5 g / 10 min, more preferably 2 to 2.5 g / 10 min, and the density is preferably 0.92 to 0.93 g / cm 3 In a specific embodiment of the present invention, the grade of low-density polyethylene used in the inner layer is 2426H, its manufacturer is CNOOC Shell, the melt index is 2g / 10min, and the density is 0.924g / cm 3 The low-density polyethylene used in the inner layer of the present invention has the characteristics of high cleanliness, good die-cutting and easy processing.

[0032] Based on the mass fraction of low-density polyethylene used in the inner layer, the raw material for preparing the inner layer includes 20 to 80 parts of metallocene polyethylene, specifically 40 parts, 45 parts, 50 parts or 60 parts; the melt index of the metallocene polyethylene used in the inner layer is preferably 1.5 to 2.5 g / 10 min, and the density is preferably 0.915 to 0.925 g / cm 3 In a specific embodiment of the present invention, the metallocene polyethylene used in the inner layer is 2018MB, its manufacturer is Exxon, the melt index is 2g / 10min, and the density is 0.918g / cm 3 The metallocene medium-density polyethylene used in the present invention has good compatibility and is easy to process.

[0033] Based on the mass fraction of low-density polyethylene used in the inner layer, the raw material for preparing the inner layer includes 10 to 30 parts of POE elastomer, specifically 10 parts, 15 parts, 20 parts or 30 parts; the POE elastomer is specifically a 1-butene-based polymer; the melt index of the POE elastomer is preferably 0.5 to 1.5 g / 10 min, more preferably 1 g / 10 min; in a specific embodiment of the present invention, the brand of the POE elastomer is BL3110M, which is a 1-butene-based polymer, produced by Mitsui Chemicals, and the melt index is 1 g / 10 min. The POE elastomer used in the present invention has good adhesion and compatibility, and is easy to peel.

[0034] In the present invention, taking the total mass of the outer layer, the middle layer and the inner layer as 100%, the mass fraction of the outer layer is preferably 20-40%, more preferably 30%, the mass fraction of the middle layer is preferably 30-60%, more preferably 40%, and the mass fraction of the inner layer is preferably 20-30%, more preferably 30%.

[0035] In the present invention, the longitudinal tensile strength of the easy-peel film is preferably 31-34 MPa, the transverse tensile strength is preferably 32-35 MPa, the longitudinal elongation at break is preferably 720-730%, the transverse elongation at break is preferably 740-750%, the longitudinal heat sealing strength is preferably 9.8-11.5N, and the transverse heat sealing strength is preferably 9.5-10.8N.

[0036] In the present invention, the thickness of the easy-to-peel film is preferably 40-60 μm, more preferably 50 μm.

[0037] The present invention also provides a method for preparing the easy-to-peel film of the above scheme, comprising the following steps: co-extruding raw materials for preparing the outer layer, the middle layer and the inner layer to obtain the easy-to-peel film.

[0038] In the present invention, the three-layer co-extrusion preferably includes: feeding the raw materials for the outer layer, the middle layer and the inner layer into the outer layer, the middle layer and the inner layer extruders respectively for melting and plasticization, conveying the obtained glue solution to the die head, extruding and blowing the film to obtain a film bubble, and after the film bubble is air-cooled, passing through a stabilizing ring and a herringbone arrangement to be pulled upward for rotation, and after the film bubble is flattened, it is inspected, trimmed, destaticized and rolled to obtain the easy-to-peel film.

[0039] In the present invention, the outer layer extruder, the middle layer extruder and the inner layer extruder are all provided with 5 heating zones, which are recorded as zones 1 to 5 in the order in which the raw materials pass; the temperature of zone 1 of the outer layer extruder is preferably 150-160°C, more preferably 150°C, the temperature of zone 2 is preferably 155-165°C, more preferably 160°C, the temperature of zone 3 is preferably 155-165°C, more preferably 160°C, the temperature of zone 4 is preferably 155-165°C, more preferably 160°C, and the temperature of zone 5 is preferably 155-165°C, more preferably 160°C; the temperature of zone 1 of the middle layer extruder is preferably 150-160°C, more preferably 160°C, and the temperature of zone 2 is preferably The temperature of zone 1 of the inner layer extruder is preferably 160-170°C, more preferably 170°C, the temperature of zone 2 is preferably 170-180°C, more preferably 180°C, the temperature of zone 3 is preferably 170-180°C, more preferably 180°C, the temperature of zone 4 is preferably 170-180°C, more preferably 175°C, and the temperature of zone 5 is preferably 170-180°C, more preferably 175°C.

[0040] In the present invention, the die head is preferably provided with 4 heating zones, which are sequentially recorded as zones 1 to 4 according to the order in which the raw materials pass; the temperature of zone 1 of the die head is preferably 170-180°C, more preferably 175°C, the temperature of zone 2 is preferably 170-180°C, more preferably 180°C, the temperature of zone 3 is preferably 170-180°C, more preferably 180°C, and the temperature of zone 4 is preferably 170-180°C, more preferably 180°C.

[0041] In the present invention, the extrusion pressure of the outer layer extruder is preferably 200-600 bar, more preferably 300-320 bar, the extrusion pressure of the middle layer extruder is preferably 250-600 bar, more preferably 300-350 bar, and the extrusion pressure of the inner layer extruder is preferably 250-600 bar, more preferably 300-330 bar.

[0042] In the present invention, the detection is preferably performed by a crystal point defect detector to detect the appearance and crystal points of the film; after the detection is completed, the edges are trimmed, and then the single sheets are separated by the lower traction roller and enter the static electricity removal device for static electricity removal, and then rolled up by the front and rear winding devices to obtain the easy-to-peel film of the present invention.

[0043] The present invention also provides the use of the easy-peel film described in the above scheme or the easy-peel film prepared by the preparation method described in the above scheme in a medical reagent tube; in the present invention, the easy-peel film is specifically used as a cap for a medical reagent tube; when the easy-peel film of the present invention is used to heat seal the medical reagent tube, the heat sealing conditions preferably include: a heat sealing temperature of 140 to 180°C, a heat sealing pressure of 300Kpa, a heat sealing time of 1s, and a heat sealing width of 15mm.

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] The invention discloses an easy-to-peel film, which is made of a co-extruded blown film of an outer layer, a middle layer and an inner layer. The weight percentages of the materials of each layer are respectively: 30% for the outer layer, 40% for the middle layer and 30% for the inner layer. The raw material ratios of each layer are shown in Table 1. The thickness of the easy-to-peel film is 50 μm.

[0047] Table 1 Example 1 Raw material ratio

[0048]

[0049] The preparation method of the easy-to-peel film is as follows: the raw materials of the outer layer, the middle layer and the inner layer are mixed in proportion by an automatic batching system, and then sent to the outer layer, the middle layer and the inner layer extruders; the raw materials of the outer layer, the middle layer and the inner layer are melted and plasticized and then sent to the die head for extrusion and blown film; and then cooled by air cooling, and the film is flattened by the upper traction rotation through a stabilizing ring and a herringbone arrangement. The film cooled by the guide roller enters the crystal point defect detector to detect the appearance and crystal points of the film, and then the trimming is separated into single sheets by the lower traction roller and enters the static elimination device and the front and rear winding devices for winding, so as to obtain the easy-to-peel film; the temperature and pressure of the outer layer, the middle layer and the inner layer extruders and the temperature of the die head are shown in Table 2.

[0050] Table 2 Extruder temperature and pressure and die head temperature

[0051] temperature Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Pressure(bar) Outer Layer 150 160 160 160 160 320 Middle level 160 170 170 170 170 350 Inner Layer 170 180 180 175 175 330 Die head 175 180 180 180 / /

[0052] Example 2

[0053] An easy-to-peel film is made of a co-extruded blown film of an outer layer, a middle layer and an inner layer. The weight percentages of the materials of each layer are: 30% for the outer layer, 40% for the middle layer and 30% for the inner layer. The amount of raw materials used for each layer is shown in Table 3. The thickness of the easy-to-peel film is 50 μm.

[0054] Table 3 Example 2 Raw material ratio

[0055]

[0056] The preparation method is the same as that in Example 1.

[0057] Example 3

[0058] An easy-to-peel film is made of a co-extruded blown film of an outer layer, a middle layer and an inner layer. The weight percentages of the materials of each layer are: 30% for the outer layer, 40% for the middle layer and 30% for the inner layer. The amount of raw materials used for each layer is shown in Table 4. The thickness of the easy-to-peel film is 50 μm.

[0059] Table 4 Example 3 Raw material ratio

[0060]

[0061]

[0062] The preparation method is the same as that of Example 3.

[0063] Comparative Example 1

[0064] An easy-to-peel film is made of a co-extruded blown film of an outer layer, a middle layer and an inner layer. The weight percentages of the materials of each layer are: 30% for the outer layer, 40% for the middle layer and 30% for the inner layer. The amount of raw materials used for each layer is shown in Table 5. The thickness of the easy-to-peel film is 50 μm.

[0065] Table 5 Comparative Example 1 Raw Material Ratio

[0066]

[0067] The preparation method is the same as that of Example 1

[0068] Comparative Example 2

[0069] An easy-to-peel film is made of a co-extruded blown film of an outer layer, a middle layer and an inner layer. The weight percentages of the materials of each layer are: 30% for the outer layer, 40% for the middle layer and 30% for the inner layer. The amount of raw materials used for each layer is shown in Table 6. The thickness of the easy-to-peel film is 50 μm.

[0070] Table 6 Comparative Example 2 Raw Material Ratio

[0071]

[0072] The preparation method is the same as that in Example 1.

[0073] Performance Testing:

[0074] The tensile strength, elongation at break, heat sealing strength and easy-to-peel condition of the easy-to-peel films prepared in Example 1 and Example 3 as well as Comparative Example 1 and Comparative Example 3 were tested, and the test results are shown in Table 7, wherein the heat sealing conditions are as follows: the heat sealing temperature is 160°C, the heat sealing pressure is 300Kpa, the heat sealing time is 1s, and the heat sealing width is 15mm; the method for judging the easy-to-peel condition is as follows: the film is sealed with the reagent tube sheet, and if the seal can be pulled open, it is easy to peel off; if it is pulled off, it is sealed and not easy to peel off.

[0075] Table 7 Performance test results

[0076]

[0077] According to the test results in Table 7, it can be seen that the easy-to-peel film of the present invention has good mechanical properties, moderate heat-sealing strength, good easy-to-peel performance, and is not prone to wire drawing, delamination, etc. when peeled off, and no residue will occur at the mouth of the reagent tube. In Comparative Example 1, the use of the inner layer POE elastomer was omitted, and the heat-sealing strength of the obtained polyethylene film was too high and difficult to peel off; in Comparative Example 2, the metallocene medium-density polyethylene in the middle layer was omitted, and although the obtained polyethylene film had moderate heat-sealing strength, delamination occurred when peeled off.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An easy-to-peel film, characterized in that: It includes outer layer, middle layer and inner layer; In terms of weight, the raw materials for preparing the outer layer include: 10 to 40 parts of low-density polyethylene and 30 to 80 parts of linear low-density polyethylene; The raw materials for preparing the middle layer include, by weight: 10 to 40 parts of low-density polyethylene, 20 to 60 parts of linear low-density polyethylene, and 30 to 80 parts of metallocene medium-density polyethylene; Calculated by weight, the raw materials for preparing the inner layer include: 20 to 80 parts of low-density polyethylene, 20 to 80 parts of metallocene polyethylene, and 10 to 30 parts of POE elastomer.

2. The easy-to-peel film according to claim 1, characterized in that: The low-density polyethylene used in the outer layer and the middle layer has a melt index of 1.5 to 2.5 g / 10 min and a density of 0.92 to 0.93 g / cm 3 The outer layer and the middle layer use linear low-density polyethylene with a melt index of 1.5 to 2.5 g / 10 min and a density of 0.915 to 0.925 g / cm 3 .

3. The easy-to-peel film according to claim 1, characterized in that: The metallocene medium-density polyethylene used in the middle layer has a melt index of 0.2-1 g / 10 min and a density of 0.93-0.94 g / cm 3 .

4. The easy-to-peel film according to claim 1, characterized in that: The low-density polyethylene used in the inner layer has a melt index of 1.5-2.5 g / 10 min and a density of 0.92-0.93 g / cm 3 The metallocene polyethylene used in the inner layer has a melt index of 1.5 to 2.5 g / 10 min and a density of 0.915 to 0.925 g / cm 3 ; The melt index of the POE elastomer used in the inner layer is 0.5 to 1.5 g / 10 min.

5. The easy-to-peel film according to claim 1, characterized in that: The grade of low-density polyethylene used in the outer layer and the middle layer is 2420H; the grade of linear low-density polyethylene used in the outer layer and the middle layer is 201XV; the grade of metallocene medium-density polyethylene used in the middle layer is 3505MC.

6. The easy-to-peel film according to claim 1, characterized in that: The brand of the low-density polyethylene used in the inner layer is 2426H; the brand of the metallocene polyethylene used in the inner layer is 2018MB; the brand of the POE elastomer used in the inner layer is BL3110M.

7. The method for preparing the easy-peel film according to any one of claims 1 to 6, comprising the following steps: The raw materials for the outer layer, the middle layer and the inner layer are co-extruded to obtain the easy-to-peel film.

8. The preparation method according to claim 7, characterized in that: The three-layer co-extrusion comprises: feeding the raw materials for the outer layer, the middle layer and the inner layer into the outer layer, the middle layer and the inner layer extruders respectively for melting and plasticizing, conveying the obtained glue liquid to the die head, extruding and blowing the film to obtain a film bubble, cooling the film bubble with air, passing through a stabilizing ring and a herringbone arrangement to be pulled upward for rotation, flattening the film bubble, conducting inspection, trimming, removing static electricity and winding, and obtaining the easy-to-peel film.

9. The preparation method according to claim 8, characterized in that: The outer layer extruder, the middle layer extruder and the inner layer extruder are all provided with 5 heating zones, which are recorded as zones 1 to 5 in the order in which the raw materials pass through; the temperature of zone 1 of the outer layer extruder is 150-160°C, the temperature of zone 2 is 155-165°C, the temperature of zone 3 is 155-165°C, the temperature of zone 4 is 155-165°C, and the temperature of zone 5 is 155-165°C; the temperature of zone 1 of the middle layer extruder is 15 0~160℃, the temperature of zone 2 is 160~170℃, the temperature of zone 3 is 160~170℃, the temperature of zone 4 is 160~170℃, and the temperature of zone 5 is 160~170℃; the temperature of zone 1 of the inner layer extruder is 160~170℃, the temperature of zone 2 is 170~180℃, the temperature of zone 3 is 170~180℃, the temperature of zone 4 is 170~180℃, and the temperature of zone 5 is 170~180℃; The die head is provided with 4 heating zones, which are respectively recorded as zones 1 to 4 according to the order in which the raw materials pass through; the temperature of zone 1 of the die head is 170-180°C, the temperature of zone 2 is 170-180°C, the temperature of zone 3 is 170-180°C, and the temperature of zone 4 is 170-180°C.

10. Use of the easy-peel film according to any one of claims 1 to 6 or the easy-peel film prepared by the preparation method according to any one of claims 7 to 9 in medical reagent tubes.

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