A high-strength plastic film and a method for producing the same

Abstract

The application relates to the technical field of plastic film, and discloses a high-strength plastic film which comprises, from inside to outside, an inner layer, a heat-sealing layer and an outer layer; the heat-sealing layer comprises an inner hot melt adhesive layer and an outer hot melt adhesive layer; the inner hot melt adhesive layer comprises the following raw materials in parts by weight: 80-100 parts of ethylene-vinyl acetate copolymer, 10-15 parts of low-density polyethylene, 1-5 parts of polyolefin elastomer and 0.5-1 part of antioxidant; and the outer hot melt adhesive layer comprises the following raw materials in parts by weight: 80-100 parts of ethylene-vinyl acetate copolymer, 10-15 parts of high-strength polypropylene, 1-5 parts of polyolefin elastomer and 0.5-1 part of antioxidant. The above technical scheme solves the problem of low strength of the plastic film in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plastic film, in particular, it relates to a kind of high-strength plastic film and preparation method thereof. BACKGROUND

[0002] Plastic film is mainly prepared by using high molecular material as raw material and adding various additives, for example, polyvinyl chloride, polyethylene, polypropylene and other resins are used as raw material to prepare plastic film, because it has good toughness, moisture resistance and heat sealing property, it is widely used in food, medicine, chemical industry, agriculture, building and other fields, at present, the main role of plastic film in most industries is packaging, such as daily necessities packaging, clothing packaging, toy packaging, etc., and for packaging materials, the most important thing is to have good tensile property, therefore, the strength requirement of plastic film in various fields is more and more strict. At present, the production process of plastic film mainly includes calendering method, flow casting method, blowing method, stretching method and the like, but the strength of plastic film prepared by these production processes is still low, which leads to the prepared film cannot be reused, therefore, preparing a kind of high-strength plastic film not only can avoid the waste of resources, but also can better meet the market demand. SUMMARY

[0003] The present application provides a kind of high-strength plastic film and preparation method thereof, solve the problem of low strength of plastic film in the related art.

[0004] The technical scheme of the present application is as follows:

[0005] The present application provides a kind of high-strength plastic film, including inner layer, heat sealing layer, outer layer arranged in turn from inside to outside, the heat sealing layer includes inner side hot melt adhesive layer, outer side hot melt adhesive layer, the inner layer includes the following weight parts of raw materials: 80~100 portions of low density polyethylene, 30~50 portions of metallocene linear low density polyethylene, 1~3 portions of opening agent;

[0006] The outer layer includes the following weight parts of raw materials:

[0007] 80~100 portions of high-strength polypropylene, 30~40 portions of linear low density polyethylene, 1~3 portions of antioxidant, 1~3 portions of light stabilizer;

[0008] The inner side hot melt adhesive layer includes the following weight parts of raw materials:

[0009] 80~100 portions of ethylene-vinyl acetate copolymer, 10~15 portions of low density polyethylene, 1~5 portions of polyolefin elastomer, 0.5~1 portions of antioxidant;

[0010] The outer side hot melt adhesive layer includes the following weight parts of raw materials:

[0011] 80~100 parts of ethylene-vinyl acetate copolymer, 10~15 parts of high-strength polypropylene, 1~5 parts of polyolefin elastomer, 0.5~1 part of antioxidant.

[0012] As a further technical solution, the mass content of ethylene-vinyl acetate copolymer in the inner hot melt adhesive layer is 15%~25%; the mass content of ethylene-vinyl acetate copolymer in the outer hot melt adhesive layer is 8%~15%.

[0013] As a further technical solution, the thickness ratio of the inner hot melt adhesive layer to the outer hot melt adhesive layer is 1:2, and the thickness of the heat sealing layer is 0.03~0.06mm.

[0014] As a further technical solution, the thickness of the inner layer is 0.02~0.03mm, and the thickness of the outer layer is 0.05~0.07mm.

[0015] As a further technical solution, the model of the low-density polyethylene is one or both of NA963 and Q281D, and the brand of the polyolefin elastomer is American Exxon 6102.

[0016] As a further technical solution, the antioxidant is one or more of antioxidant 1076, antioxidant 1010, and antioxidant 168.

[0017] As a further technical solution, the light stabilizer is one or more of light stabilizer UV120, light stabilizer UV123, and light stabilizer UV622.

[0018] As a further technical solution, the opening agent is one or more of talc, calcium carbonate, and diatomite.

[0019] The application also provides a preparation method of the high-strength plastic film.

[0020] S1, mixing raw materials of the inner hot melt adhesive layer of the heat sealing layer, melting and extruding to obtain inner hot melt adhesive extrudate;

[0021] S2, mixing raw materials of the outer hot melt adhesive layer of the heat sealing layer, melting and extruding to obtain outer hot melt adhesive extrudate;

[0022] S3, mixing the inner layer, the inner hot melt adhesive extrudate, the outer hot melt adhesive extrudate, and the outer layer, co-extruding, molding through a die, and cooling to obtain the high-strength plastic film.

[0023] As a further technical solution, the heating temperature of the inner hot melt adhesive layer mixing in step S1 is 100-130 DEG C, and the rotating speed is 100-130 r / min; the heating temperature of the outer hot melt adhesive layer mixing in step S2 is 100-130 DEG C, and the rotating speed is 120-150 r / min; the heating temperature of the mixing in step S3 is 130-150 DEG C, and the rotating speed is 150-200 r / min.

[0024] As a further technical solution, the cooling in step S3 adopts a segmented cooling mode, the first segment cooling rate is 15-20 DEG C / min, and the second segment cooling rate is 30-40 DEG C / min.

[0025] As a further technical solution, the temperature of the die in step S3 is 275-290 DEG C.

[0026] The working principle and beneficial effects of the present application are as follows:

[0027] 1. In the present application, the plastic film is divided into an inner layer, a hot melt adhesive layer, and an outer layer, and the heat sealing layer is divided into an inner hot melt adhesive layer and an outer hot melt adhesive layer, wherein the inner hot melt adhesive layer uses ethylene-vinyl acetate copolymer, low-density polyethylene, polyolefin elastomer, and antioxidant as raw materials, and the outer hot melt adhesive layer uses ethylene-vinyl acetate copolymer, high-strength polypropylene, polyolefin elastomer, and antioxidant as raw materials, and the strength of the plastic film is significantly improved by the two hot melt adhesive layers and the different raw materials of the two hot melt adhesive layers.

[0028] 2. In the present application, when the thickness ratio of the inner hot melt adhesive layer and the outer hot melt adhesive layer is set to 1:2, the strength of the plastic film is further improved.

[0029] 3. In the present application, the strength of the plastic film is further improved by the different vinyl acetate contents of ethylene-vinyl acetate copolymer in the inner hot melt adhesive layer and the outer hot melt adhesive layer.

[0030] 4. In the present application, the strength of the plastic film is further improved by using a segmented cooling process. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are involved in the scope of protection of the present application.

[0032] Embodiment 1

[0033] A high-strength plastic film comprises an inner layer, a heat-sealing layer, and an outer layer, the heat-sealing layer comprises an inner hot melt adhesive layer and an outer hot melt adhesive layer,

[0034] The inner layer comprises 80 parts of low-density polyethylene, 30 parts of metallocene linear low-density polyethylene, and 1 part of talcum powder.

[0035] The outer layer comprises 80 parts of high-strength polyethylene, 30 parts of linear low-density polyethylene, 1 part of antioxidant, and 1 part of light stabilizer UV120.

[0036] The inner hot melt adhesive layer comprises 80 parts of ethylene-vinyl acetate copolymer, 10 parts of low-density polyethylene of type NA963, 1 part of polyolefin elastomer, and 0.5 parts of antioxidant 1076.

[0037] The outer hot melt adhesive layer comprises 80 parts of ethylene-vinyl acetate copolymer, 10 parts of high-strength polypropylene, 1 part of polyolefin elastomer, and 0.5 parts of antioxidant 1076.

[0038] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the inner hot melt adhesive layer is 15%.

[0039] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the outer hot melt adhesive layer is 8%.

[0040] The thickness ratio of the inner hot melt adhesive layer to the outer hot melt adhesive layer is 1:2, and the thickness of the heat-sealing layer is 0.03 mm.

[0041] The thickness of the inner layer is 0.02 mm, and the thickness of the outer layer is 0.05 mm.

[0042] A method for preparing a high-strength plastic film is provided.

[0043] S1, mixing raw materials of ethylene-vinyl acetate copolymer, low-density polyethylene, polyolefin elastomer, and antioxidant of the inner hot melt adhesive layer of the heat-sealing layer at 100 r / min, heating to 100℃ to melt, and extruding through a single-screw extruder to obtain an inner hot melt adhesive extrusion material;

[0044] S2, mixing raw materials of ethylene-vinyl acetate copolymer, high-strength polyethylene, polyolefin elastomer, and antioxidant of the outer hot melt adhesive layer of the heat-sealing layer at 120 r / min, heating to 100℃ to melt, and extruding through a single-screw extruder to obtain an outer hot melt adhesive extrusion material;

[0045] S3, mixing the inner layer raw material, the inner hot melt adhesive extrusion material, the outer hot melt adhesive extrusion material, and the outer layer raw material at 150 r / min, heating to 130℃ to melt, co-extruding through a double-screw extruder, molding through a die at 275℃, and performing first-stage cooling at a rate of 15℃ / min and second-stage cooling at a rate of 30℃ / min to obtain a high-strength plastic film.

[0046] Embodiment 2

[0047] The high-strength plastic film comprises an inner layer, a heat-sealing layer, and an outer layer, wherein the heat-sealing layer comprises an inner hot melt adhesive layer and an outer hot melt adhesive layer,

[0048] The inner layer comprises 90 parts of low-density polyethylene, 40 parts of metallocene linear low-density polyethylene, and 2 parts of calcium carbonate.

[0049] The outer layer comprises 90 parts of high-strength polyethylene, 40 parts of linear low-density polyethylene, 2 parts of an antioxidant, and 2 parts of a light stabilizer UV123.

[0050] The inner hot melt adhesive layer comprises 90 parts of ethylene-vinyl acetate copolymer, 15 parts of low-density polyethylene of type Q281, 3 parts of polyolefin elastomer, and 0.8 parts of antioxidant 1010.

[0051] The outer hot melt adhesive layer comprises 90 parts of ethylene-vinyl acetate copolymer, 15 parts of high-strength polypropylene, 3 parts of polyolefin elastomer, and 0.8 parts of antioxidant 1010.

[0052] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the inner hot melt adhesive layer is 20%.

[0053] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the outer hot melt adhesive layer is 10%.

[0054] The thickness ratio of the inner hot melt adhesive layer to the outer hot melt adhesive layer is 1:2, and the thickness of the heat-sealing layer is 0.045 mm.

[0055] The thickness of the inner layer is 0.025 mm, and the thickness of the outer layer is 0.06 mm.

[0056] A method for preparing a high-strength plastic film is provided.

[0057] S1. The raw materials of the inner hot melt adhesive layer of the heat-sealing layer, i.e., ethylene-vinyl acetate copolymer, low-density polyethylene, polyolefin elastomer, and antioxidant, are mixed at 120 r / min, heated to 120°C to melt, and extruded through a single-screw extruder to obtain an inner hot melt adhesive extrusion material.

[0058] S2. The raw materials of the outer hot melt adhesive layer of the heat-sealing layer, i.e., ethylene-vinyl acetate copolymer, high-strength polyethylene, polyolefin elastomer, and antioxidant, are mixed at 130 r / min, heated to 120°C to melt, and extruded through a single-screw extruder to obtain an outer hot melt adhesive extrusion material.

[0059] S3, the inner layer raw material, the inner side hot melt adhesive extrusion material, the outer side hot melt adhesive extrusion material, the outer layer raw material are mixed at 180 r / min, heated to 140℃ melting, co-extruded through double screw extruder, molded through 285℃ die, the first stage cooling is carried out at the rate of 18℃ / min, the second stage cooling is carried out at the rate of 35℃ / min, high-strength plastic film is obtained.

[0060] Example 3

[0061] The high-strength plastic film comprises an inner layer, a heat-sealing layer and an outer layer, the heat-sealing layer comprises an inner side hot melt adhesive layer and an outer side hot melt adhesive layer,

[0062] The inner layer comprises 100 parts of low-density polyethylene, 50 parts of metallocene linear low-density polyethylene and 3 parts of diatomite.

[0063] The outer layer comprises 100 parts of high-strength polyethylene, 40 parts of linear low-density polyethylene, 3 parts of antioxidant and 3 parts of light stabilizer UV622.

[0064] The inner side hot melt adhesive layer comprises 100 parts of ethylene-vinyl acetate copolymer, 15 parts of NA963 type low-density polyethylene, 5 parts of polyolefin elastomer and 1 part of antioxidant 168.

[0065] The outer side hot melt adhesive layer comprises 100 parts of ethylene-vinyl acetate copolymer, 15 parts of high-strength polypropylene, 5 parts of polyolefin elastomer and 1 part of antioxidant 168.

[0066] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the inner side hot melt adhesive layer is 25%.

[0067] The mass content of vinyl acetate in the ethylene-vinyl acetate copolymer in the outer side hot melt adhesive layer is 15%.

[0068] The thickness ratio of the inner side hot melt adhesive layer to the outer side hot melt adhesive layer is 1:2, and the thickness of the heat-sealing layer is 0.06 mm.

[0069] The thickness of the inner layer is 0.03 mm, and the thickness of the outer layer is 0.07 mm.

[0070] The preparation method of the high-strength plastic film comprises the following steps:

[0071] S1, the inner side hot melt adhesive layer raw material ethylene-vinyl acetate copolymer, low-density polyethylene, polyolefin elastomer and antioxidant of the heat-sealing layer are mixed at 130 r / min, heated to 130℃ melting, extruded through a single screw extruder, and an inner side hot melt adhesive extrusion material is obtained.

[0072] S2, the outer side hot melt adhesive layer raw material of heat sealing layer ethylene-vinyl acetate copolymer, high strength polypropylene, polyolefin elastomer, antioxidant is mixed under 150r / min, heating to 130℃ melting, extruding through single screw extruder, obtaining outer side hot melt adhesive extrusion material;

[0073] S3, the inner layer raw material, the outer side hot melt adhesive extrusion material, the outer side hot melt adhesive extrusion material, the outer layer raw material is mixed under 200r / min, heating to 150℃ melting, co-extruding through double screw extruder, forming through 290℃ die, first stage cooling at 20℃ / min rate, second stage cooling at 40℃ / min rate, obtaining high strength plastic film.

[0074] Example 4

[0075] The difference between this embodiment and example 1 is only that the thickness ratio of inner side hot melt adhesive layer and outer side hot melt adhesive layer is 1:3.

[0076] Example 5

[0077] The difference between this embodiment and example 1 is only that the thickness ratio of inner side hot melt adhesive layer and outer side hot melt adhesive layer is 1:1.

[0078] Example 6

[0079] The difference between this embodiment and example 1 is only that the vinyl acetate content of ethylene-vinyl acetate copolymer in inner side hot melt adhesive layer and outer side hot melt adhesive layer is 15%.

[0080] Example 7

[0081] The difference between this embodiment and example 1 is only that the vinyl acetate content of ethylene-vinyl acetate copolymer in inner side hot melt adhesive layer and outer side hot melt adhesive layer is 25%.

[0082] Example 8

[0083] The difference between this embodiment and example 1 is only that the preparation method of high strength plastic film:

[0084] S1, the inner side hot melt adhesive layer raw material of heat sealing layer ethylene-vinyl acetate copolymer, low density polyethylene, polyolefin elastomer, antioxidant is mixed under 100r / min, heating to 100℃ melting, extruding through single screw extruder, obtaining inner side hot melt adhesive extrusion material;

[0085] S2, the outer side hot melt adhesive layer raw material of heat sealing layer ethylene-vinyl acetate copolymer, high strength polypropylene, polyolefin elastomer, antioxidant is mixed under 120r / min, heating to 100℃ melting, extruding through single screw extruder, obtaining outer side hot melt adhesive extrusion material;

[0086] S3, the inner layer, the inner side hot melt adhesive extrusion material, the outer side hot melt adhesive extrusion material and the outer layer raw material are mixed at 150 r / min, heated to 130℃ for melting, co-extruded through a double screw extruder, molded through a die head of 275℃, only the first stage cooling is carried out at a rate of 15℃ / min, and a high-strength plastic film is obtained.

[0087] Example 9

[0088] The difference between this example and example 1 is only in the preparation method of the high-strength plastic film:

[0089] S1, the inner side hot melt adhesive layer raw material ethylene-vinyl acetate copolymer, low density polyethylene, polyolefin elastomer and antioxidant of the heat sealing layer are mixed at 100 r / min, heated to 100℃ for melting, and extruded through a single screw extruder to obtain the inner side hot melt adhesive extrusion material;

[0090] S2, the outer side hot melt adhesive layer raw material ethylene-vinyl acetate copolymer, high-strength polypropylene, polyolefin elastomer and antioxidant of the heat sealing layer are mixed at 120 r / min, heated to 100℃ for melting, and extruded through a single screw extruder to obtain the outer side hot melt adhesive extrusion material;

[0091] S3, the inner layer raw material, the inner side hot melt adhesive extrusion material, the outer side hot melt adhesive extrusion material and the outer layer raw material are mixed at 150 r / min, heated to 130℃ for melting, co-extruded through a double screw extruder, molded through a die head of 275℃, and only the second stage cooling is carried out at a rate of 30℃ / min to obtain a high-strength plastic film.

[0092] Comparative Example 1

[0093] The difference between this comparative example and example 1 is only that the heat sealing layer only includes the inner side hot melt adhesive layer.

[0094] Comparative Example 2

[0095] The difference between this comparative example and example 1 is only that the heat sealing layer only includes the outer side hot melt adhesive layer.

[0096] Comparative Example 3

[0097] The difference between this comparative example and example 1 is only that the low density polyethylene in the inner side hot melt adhesive layer is replaced by polyethylene.

[0098] Comparative Example 4

[0099] The difference between this comparative example and example 1 is only that the high-strength polypropylene in the outer side hot melt adhesive layer is replaced by polypropylene.

[0100] The raw materials used in the examples and comparative examples of the present application are shown in the following table:

[0101]

[0102] The high-strength plastic films prepared from Examples 1-9 and Comparative Examples 1-4 are tested according to GB / T 1040.3-2006 standard

[0103] Performance tests are shown in the following table:

[0104]

[0105] According to the data of Examples 1-9 and Comparative Examples 1-4, it can be seen that the strength of the plastic film is significantly improved by dividing the heat-sealing layer into an inner hot melt adhesive layer and an outer hot melt adhesive layer and by using different raw materials for the inner hot melt adhesive layer and the outer hot melt adhesive layer.

[0106] According to the data of Examples 1-3 and Examples 4-5, it can be seen that the strength of the plastic film is further improved by setting the thickness ratio of the inner hot melt adhesive layer to the outer hot melt adhesive layer to 1:2.

[0107] According to the data of Examples 1-3 and Examples 6-7, it can be seen that the strength of the plastic film is further improved by using different vinyl acetate contents of ethylene-vinyl acetate copolymer in the inner hot melt adhesive layer and the outer hot melt adhesive layer.

[0108] According to the data of Examples 1-3 and Examples 8-9, it can be seen that the strength of the plastic film is further improved by using a segmented cooling process.

[0109] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high-strength plastic film, comprising an inner layer, a heat-sealing layer, and an outer layer arranged sequentially from the inside out, characterized in that, The heat-sealing layer includes an inner hot melt adhesive layer and an outer hot melt adhesive layer. The inner layer includes the following raw materials in parts by weight: 80-100 parts low-density polyethylene, 30-50 parts metallocene linear low-density polyethylene, and 1-3 parts opening agent. The outer layer comprises the following raw materials in parts by weight: 80-100 parts high-strength polypropylene, 30-40 parts linear low-density polyethylene, 1-3 parts antioxidant, 1-3 parts light stabilizer; The inner hot melt adhesive layer comprises the following raw materials in parts by weight: 80-100 parts ethylene-vinyl acetate copolymer, 10-15 parts low-density polyethylene, 1-5 parts polyolefin elastomer, 0.5-1 part antioxidant; The outer hot melt adhesive layer comprises the following raw materials in parts by weight: 80-100 parts ethylene-vinyl acetate copolymer, 10-15 parts high-strength polypropylene, 1-5 parts polyolefin elastomer, 0.5-1 part antioxidant; The high-strength polypropylene is designated as RB307MO.

2. The high-strength plastic film according to claim 1, characterized in that, The inner hot melt adhesive layer contains 15% to 25% vinyl acetate by mass of the ethylene-vinyl acetate copolymer; the outer hot melt adhesive layer contains 8% to 15% vinyl acetate by mass of the ethylene-vinyl acetate copolymer.

3. The high-strength plastic film according to claim 1, characterized in that, The thickness ratio of the inner hot melt adhesive layer to the outer hot melt adhesive layer is 1:2, and the thickness of the heat-sealing layer is 0.03~0.06mm; the thickness of the inner layer is 0.02~0.03mm, and the thickness of the outer layer is 0.05~0.07mm.

4. The high-strength plastic film according to claim 1, characterized in that, The low-density polyethylene is of type NA963 or type Q281D, or both.

5. A high-strength plastic film according to claim 1, characterized in that, The antioxidant is one or more of antioxidant 1076, antioxidant 1010, and antioxidant 168.

6. A high-strength plastic film according to claim 1, characterized in that, The light stabilizer is one or more of light stabilizer UV120, light stabilizer UV123, and light stabilizer UV622; the opening agent is one or more of talc, calcium carbonate, and diatomaceous earth.

7. A method for preparing a high-strength plastic film according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Mix the raw materials of the inner hot melt adhesive layer of the heat-sealing layer, melt and extrude to obtain the inner hot melt adhesive extrusion; S2. Mix the raw materials of the outer hot melt adhesive layer of the heat-sealing layer, melt and extrude to obtain the outer hot melt adhesive extrusion; S3. Mix the inner layer, inner hot melt adhesive extruder, outer hot melt adhesive extruder, and outer layer, melt and co-extrude them, form them through a die head, and cool them to obtain a high-strength plastic film.

8. A method for preparing a high-strength plastic film according to claim 7, characterized in that, In step S1, the heating temperature for mixing the inner hot melt adhesive layer is 100~130℃, and the rotation speed is 100~130 r / min; in step S2, the heating temperature for mixing the outer hot melt adhesive layer is 100~130℃, and the rotation speed is 120~150 r / min; in step S3, the heating temperature for mixing is 130~150℃, and the rotation speed is 150~200 r / min.

9. The method for preparing a high-strength plastic film according to claim 7, characterized in that, In step S3, the cooling is performed in stages, with the first stage having a cooling rate of 15~20℃ / min and the second stage having a cooling rate of 30~40℃ / min.

10. The method for preparing a high-strength plastic film according to claim 7, characterized in that, In step S3, the temperature of the die head is 275~290℃.

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