Composition for preparing easy-to-tear material, easy-to-tear material and preparation method of easy-to-tear material

Abstract

The invention relates to the field of high polymer materials, and discloses a composition for preparing an easy-to-peel material, the easy-to-peel material and a preparation method of the easy-to-peel material. The composition comprises the following components: an ethylene-vinyl acetate copolymer, polyethylene, a tackifier, a lubricant, a dispersant and an antioxidant, based on the total weight of the composition, the content of the ethylene-vinyl acetate copolymer is 40 to 80 wt%, the content of the polyethylene is 14 to 50 wt%, the content of the tackifier is 1 to 10 wt%, the content of the lubricant is 0.01 to 0.5 wt%, the content of the dispersant is 0.01 to 0.5 wt%, and the content of the antioxidant is 0.05 to 0.5 wt%. The material prepared from the composition provided by the invention has the characteristics of low heat sealing temperature, good heat adhesiveness and easiness in tearing.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a composition for preparing an easy-to-tear material, the easy-to-tear material and a preparation method thereof. Background Art

[0002] Low-temperature heat-sealable, easy-to-peel material is a widely used hot-melt sealant in plastic packaging, widely used in lidding for cans, boxes, dishes, bottles, and more. The basic requirements for this material are: first, good low-temperature heat sealing properties, meaning the heat sealing temperature must be low; second, good thermal adhesion, ensuring a reliable, leak-proof seal; third, easy peeling, requiring minimal force; and fourth, ease of coating, allowing for application by extrusion coating, roller coating, or brushing. Furthermore, it should exhibit excellent heat, oil, acid, and alkali resistance.

[0003] This low-temperature heat-sealable and easy-to-tear material can be used on aluminum foil, iron foil, paper or plastic sealing materials, and can also be used on the heat-sealing surface of composite material covering materials, such as: instant noodle covering materials for box and barrel packaging, aluminum foil covering materials for milk powder in iron and aluminum barrels, medicinal PTP, jelly packaging, etc.

[0004] Zhou Xiangxing et al. (Zhou Xiangxing, Formulation and Application of Low-Temperature Heat-Sealable, Easy-Tear Peelable Material) studied the formulation of a low-temperature heat-sealable, easy-tear peelable material. The resulting material exhibited excellent thermal adhesion and was easily peelable when heat-sealed at a temperature between 130°C and 160°C. However, this prior art suffers from the drawbacks of high heat-sealing temperatures and high tear strength. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a material with low heat sealing temperature, good thermal adhesion and easy tearing.

[0006] In order to achieve the above object, the first aspect of the present invention provides a composition for preparing an easy-to-tear material, wherein the composition comprises the following components:

[0007] Ethylene vinyl acetate copolymer, polyethylene, tackifiers, lubricants, dispersants and antioxidants;

[0008] Based on the total weight of the composition, the content of the ethylene-vinyl acetate copolymer is 40-80wt%, the content of the polyethylene is 14-50wt%, the content of the tackifier is 1-10wt%, the content of the lubricant is 0.01-0.5wt%, the content of the dispersant is 0.01-0.5wt%, and the content of the antioxidant is 0.05-0.5wt%;

[0009] The density of the polyethylene is 0.918-0.922 g / cm 3 , the melt index at 190℃ under a load of 2.16kg is 1-10g / 10min;

[0010] The ethylene-vinyl acetate copolymer is prepared by a method comprising the following steps:

[0011] In the presence of an organic peroxide, ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain an ethylene-vinyl acetate copolymer melt; and the ethylene-vinyl acetate copolymer melt is extruded and granulated I;

[0012] The polymerization reaction conditions include: temperature of 190-310°C and pressure of 260-320 MPa;

[0013] The feed rate of the ethylene monomer is 15-19 t / h; the pumping speed of the vinyl acetate monomer is 100-1000 rpm.

[0014] The second aspect of the present invention provides a method for preparing an easily tearable material, which is performed using the composition described in the first aspect, comprising:

[0015] Ethylene-vinyl acetate copolymer, polyethylene, a tackifier, a lubricant, a dispersant and an antioxidant are mixed and then subjected to extrusion granulation II to obtain pellets; and the pellets are subjected to a casting film forming process.

[0016] The third aspect of the present invention provides an easy-to-tear material prepared by the method described in the second aspect.

[0017] The present invention uses ethylene-vinyl acetate copolymer obtained by polymerization under high temperature and high pressure conditions, combines it with a specific type and specific content of polyethylene, and supplements it with specific amounts of additives such as tackifiers and lubricants to prepare a non-toxic and environmentally friendly material with a low heat sealing temperature, good thermal adhesion and easy tearing.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0020] As mentioned above, the first aspect of the present invention provides a composition for preparing an easy-to-tear material, the composition comprising the following components:

[0021] Ethylene vinyl acetate copolymer, polyethylene, tackifiers, lubricants, dispersants and antioxidants;

[0022] Based on the total weight of the composition, the content of the ethylene-vinyl acetate copolymer is 40-80wt%, the content of the polyethylene is 14-50wt%, the content of the tackifier is 1-10wt%, the content of the lubricant is 0.01-0.5wt%, the content of the dispersant is 0.01-0.5wt%, and the content of the antioxidant is 0.05-0.5wt%;

[0023] The density of the polyethylene is 0.918-0.922 g / cm 3 , the melt index at 190℃ under a load of 2.16kg is 1-10g / 10min;

[0024] The ethylene-vinyl acetate copolymer is prepared by a method comprising the following steps:

[0025] In the presence of an organic peroxide, ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain an ethylene-vinyl acetate copolymer melt; and the ethylene-vinyl acetate copolymer melt is extruded and granulated I;

[0026] The polymerization reaction conditions include: temperature of 190-310°C and pressure of 260-320 MPa;

[0027] The feed rate of the ethylene monomer is 15-19 t / h; the pumping speed of the vinyl acetate monomer is 100-1000 rpm.

[0028] Preferably, the feed rate of the organic peroxide is 2-4 kg / h.

[0029] Preferably, the conditions of the extrusion granulation I include: a temperature of 170-210° C. and a rotation speed of 200-500 rpm.

[0030] Preferably, the organic peroxide is at least one selected from the group consisting of tert-butyl perbenzoate, tert-butyl perbenzoate, tert-butyl peroxide-2-ethylhexyl ester, tert-butyl peroxide pivalate and tert-butyl peroxide neodecanoate.

[0031] Preferably, the vinyl acetate structural unit content of the ethylene-vinyl acetate copolymer is 6-28 wt %, more preferably 8-20 wt %.

[0032] Preferably, the ethylene-vinyl acetate copolymer has a melt index of 2-15 g / 10 min at 190° C. and a load of 2.16 kg.

[0033] According to a preferred embodiment, the tackifier is selected from at least one of rosin resin, C5 petroleum resin and C9 petroleum resin.

[0034] More preferably, the tackifier has a softening point of 100-175° C. and a molecular weight of 1000-20000. The inventors of the present invention have found that the material prepared under this preferred condition has better bonding properties.

[0035] According to another preferred embodiment, the lubricant is selected from at least one of oleamide and erucamide.

[0036] Preferably, the dispersant is selected from at least one of silicon oxide, zinc stearate, and polyethylene glycol. Particularly preferably, the dispersant is polyethylene glycol. The inventors of the present invention have discovered that, in this preferred embodiment, the resulting material exhibits improved optical and adhesive properties.

[0037] Preferably, the antioxidant is selected from at least one of hindered phenol antioxidants, aromatic amine antioxidants and auxiliary antioxidants.

[0038] More preferably, the hindered phenol antioxidant is selected from at least one of 2,6-di-tert-butyl-p-methylphenol (antioxidant 264), bis(3,5-tert-butyl-4-hydroxyphenyl) sulfide and pentaerythritol tetrakis{β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010).

[0039] More preferably, the aromatic amine antioxidant is selected from at least one of diphenylamine, p-phenylenediamine and dihydroquinoline compounds.

[0040] Preferably, the auxiliary antioxidant is selected from at least one phosphite antioxidant.

[0041] As mentioned above, the second aspect of the present invention provides a method for preparing an easily tearable material, which is performed using the composition described in the first aspect, comprising:

[0042] Ethylene-vinyl acetate copolymer, polyethylene, a tackifier, a lubricant, a dispersant and an antioxidant are mixed and then subjected to extrusion granulation II to obtain pellets; and the pellets are subjected to a casting film forming process.

[0043] According to a particularly preferred embodiment, the mixing method includes: first performing low-speed mixing and then performing high-speed mixing. The inventors of the present invention have found that the material prepared under this preferred condition has better dispersion properties.

[0044] Preferably, the low-speed mixing conditions include: stirring at a speed of 200-600 rpm, a temperature of 25-65° C., and a time of 1-3 min.

[0045] Preferably, the high-speed mixing conditions include: stirring at a speed of 1000-1500 rpm, a temperature of 40-60° C., and a time of 1-3 min.

[0046] Preferably, the conditions of the extrusion granulation II include: a temperature of 150-200° C. and a rotation speed of 150-300 rpm.

[0047] Preferably, the conditions of the tape casting film forming process include: a temperature of 180-210°C.

[0048] As mentioned above, the third aspect of the present invention provides an easy-to-tear material prepared by the method described in the second aspect.

[0049] The present invention will be described in detail below through examples.

[0050] In the following examples, unless otherwise specified, all raw materials used are commercially available.

[0051] In the following examples, the test methods for each characteristic parameter are as follows:

[0052] Vinyl acetate structural unit content: determined using the method in SH / T 1591-1994;

[0053] Melt index: measured using the method in GB / T 3682.1-2018. The test conditions are: temperature 190°C, load 2.16 kg.

[0054] Organic peroxides:

[0055] Peroxide I: tert-butyl peroxybenzoate;

[0056] Peroxide II: tert-butyl peroxybenzoate;

[0057] Polyethylene:

[0058] Polyethylene I: Brand: YG224C, density: 0.922g / cm 3 , melt index is 3.5g / 10min, purchased from Yanshan Petrochemical;

[0059] Polyethylene II: brand TJVL-1210, density 0.921g / cm 3 , melt index is 1.0g / 10min, purchased from Tianjin Petrochemical;

[0060] Polyethylene III: brand 1C7A, density 0.918g / cm 3 , melt index is 0.7g / 10min, purchased from Yanshan Petrochemical;

[0061] Tackifier:

[0062] Tackifier I-1: C5 petroleum resin, softening point 105°C, molecular weight 1500, purchased from Henan Puyang Zhongke Xinyuan Company;

[0063] Tackifier I-2: C5 petroleum resin, softening point 115°C, molecular weight 1700, purchased from Henan Puyang Zhongke Xinyuan Company;

[0064] Tackifier II: C9 petroleum resin, softening point 135°C, molecular weight 2000, purchased from Henan Puyang Zhongke Xinyuan Company;

[0065] Tackifier III: rosin resin, softening point 165°C, molecular weight 3000, purchased from Henan Puyang Zhongke Xinyuan Company;

[0066] Lubricant:

[0067] Lubricant I: erucamide;

[0068] Lubricant II: oleamide;

[0069] Dispersants:

[0070] Dispersant I: polyethylene glycol, molecular weight 16000, purchased from Henan Puyang Zhongke Xinyuan Company;

[0071] Dispersant II: zinc stearate;

[0072] Antioxidants:

[0073] Antioxidant I: Antioxidant 1010;

[0074] Antioxidant II: Antioxidant 168.

[0075] Preparation Example 1

[0076] In the presence of an organic peroxide (peroxide I), ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain an ethylene-vinyl acetate copolymer melt; and the ethylene-vinyl acetate copolymer melt is extruded and granulated I;

[0077] The polymerization reaction conditions included: temperature of 200°C and pressure of 300 MPa;

[0078] The feed rate of ethylene monomer is 15t / h; the pump speed of vinyl acetate monomer is 200rpm; the feed rate of organic peroxide is 2kg / h;

[0079] The conditions for extrusion granulation I were as follows: the extruder was operated in a twin-screw machine at a temperature of 180°C and a rotation speed of 200 rpm;

[0080] Ethylene-vinyl acetate copolymer J1 was prepared.

[0081] Preparation Example 2

[0082] In the presence of an organic peroxide (peroxide II), ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain an ethylene-vinyl acetate copolymer melt; and the ethylene-vinyl acetate copolymer melt is extruded and granulated I;

[0083] The polymerization reaction conditions included: temperature of 240°C and pressure of 265 MPa;

[0084] The feed rate of ethylene monomer is 18 t / h; the pump speed of vinyl acetate monomer is 500 rpm; the feed rate of organic peroxide is 3 kg / h;

[0085] The conditions for extrusion granulation I were as follows: carried out in a twin-screw machine at a temperature of 180°C and a rotation speed of 500 rpm;

[0086] Ethylene-vinyl acetate copolymer J2 was prepared.

[0087] Comparative Preparation Example 1

[0088] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0089] The polymerization reaction conditions were: temperature 180°C, pressure 245 MPa;

[0090] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ1.

[0091] Comparative Preparation Example 2

[0092] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0093] The pumping speed of vinyl acetate monomer was 80 rpm;

[0094] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ2.

[0095] Example 1

[0096] The formula of the easy-to-tear material is as follows:

[0097] 45 parts by weight of ethylene-vinyl acetate copolymer J1, 45 parts by weight of polyethylene I, 10 parts by weight of tackifier I-1, 0.2 parts by weight of lubricant I, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0098] The method for preparing the easy-to-tear material is as follows:

[0099] Ethylene-vinyl acetate copolymer, polyethylene, tackifier, lubricant, dispersant and antioxidant are first mixed at a low speed, then mixed at a high speed, and then extruded into granules II to obtain granules A1;

[0100] The low-speed mixing conditions are: stirring under the conditions of 500 rpm, 40°C, and 3 min;

[0101] The high-speed mixing conditions are as follows: stirring at a speed of 1200 rpm, a temperature of 40°C, and a time of 1 min;

[0102] The conditions for extrusion granulation II were as follows: the extruder was operated in a twin-screw machine at a temperature of 180°C and a rotation speed of 200 rpm;

[0103] The pellet A1 is subjected to a casting film forming process to obtain a cast film S1 with a thickness of 60 μm;

[0104] The conditions for the film casting process were as follows: temperatures of 180°C, 185°C, 185°C, 195°C, 200°C, and 195°C.

[0105] Example 2

[0106] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0107] The formula of the easy-to-tear material is as follows:

[0108] 70 parts by weight of ethylene-vinyl acetate copolymer J1, 22 parts by weight of polyethylene I, 8 parts by weight of tackifier I-1, 0.2 parts by weight of lubricant I, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0109] The remaining conditions were the same as those in Example 1, and pellets A2 and cast film S2 were prepared.

[0110] Example 3

[0111] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0112] The formula of the easy-to-tear material is as follows:

[0113] 60 parts by weight of ethylene-vinyl acetate copolymer J2, 30 parts by weight of polyethylene I, 10 parts by weight of tackifier III, 0.2 parts by weight of lubricant II, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0114] The remaining conditions were the same as those in Example 1, and pellets A3 and cast film S3 were prepared.

[0115] Example 4

[0116] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0117] The formula of the easy-to-tear material is as follows:

[0118] 70 parts by weight of ethylene-vinyl acetate copolymer J1, 22 parts by weight of polyethylene II, 8 parts by weight of tackifier II, 0.2 parts by weight of lubricant II, 0.2 parts by weight of dispersant II, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0119] The remaining conditions were the same as those in Example 1, and pellets A4 and cast film S4 were prepared.

[0120] Example 5

[0121] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0122] The formula of the easy-to-tear material is as follows:

[0123] 70 parts by weight of ethylene-vinyl acetate copolymer J1, 22 parts by weight of polyethylene II, 8 parts by weight of tackifier II, 0.2 parts by weight of lubricant II, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0124] The remaining conditions were the same as those in Example 1, and pellets A5 and cast film S5 were prepared.

[0125] Example 6

[0126] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0127] The formula of the easy-to-tear material is as follows:

[0128] 80 parts by weight of ethylene-vinyl acetate copolymer J2, 15 parts by weight of polyethylene I, 5 parts by weight of tackifier III, 0.3 parts by weight of lubricant II, 0.3 parts by weight of dispersant II, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0129] The remaining conditions were the same as those in Example 1, and pellets A6 and cast film S6 were prepared.

[0130] Example 7

[0131] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0132] The tackifier is 10 parts by weight of tackifier I-2;

[0133] The remaining conditions were the same as those in Example 1, and pellets A7 and cast film S7 were prepared.

[0134] Comparative Example 1

[0135] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0136] The formula of the easy-to-tear material is as follows:

[0137] 90 parts by weight of ethylene-vinyl acetate copolymer J2, 10 parts by weight of tackifier III, 0.2 parts by weight of lubricant I, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0138] The remaining conditions were the same as those in Example 1, and pellets DA1 and cast film DS1 were prepared.

[0139] Comparative Example 2

[0140] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0141] The formula of the easy-to-tear material is as follows:

[0142] 60 parts by weight of ethylene-vinyl acetate copolymer J1, 20 parts by weight of polyethylene I, 20 parts by weight of tackifier III, 0.2 parts by weight of lubricant I, 0.2 parts by weight of dispersant I, 0.1 parts by weight of antioxidant I, and 0.2 parts by weight of antioxidant II;

[0143] The remaining conditions were the same as those in Example 1, and pellets DA2 and cast film DS2 were prepared.

[0144] Comparative Example 3

[0145] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0146] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ1;

[0147] The remaining conditions were the same as those in Example 1, and pellets DA3 and cast film DS3 were prepared.

[0148] Comparative Example 4

[0149] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0150] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ2;

[0151] The remaining conditions were the same as those in Example 1, and pellets DA4 and cast film DS4 were prepared.

[0152] Comparative Example 5

[0153] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0154] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ2;

[0155] The remaining conditions were the same as those in Example 1, and pellets DA5 and cast film DS5 were prepared.

[0156] Comparative Example 6

[0157] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0158] The polyethylene is polyethylene III;

[0159] The remaining conditions were the same as those in Example 1, and pellets DA6 and cast film DS6 were prepared.

[0160] Comparative Example 7

[0161] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0162] The dispersant is 1 part by weight of dispersant I;

[0163] The remaining conditions were the same as those in Example 1, and pellets DA7 and cast film DS7 were prepared.

[0164] Test Case

[0165] The relevant parameters of the ethylene-vinyl acetate copolymers prepared in the preparation examples and comparative preparation examples are shown in Table 1;

[0166] The test methods for the relevant parameters of the pellets and cast films prepared in the Examples and Comparative Examples are as follows. The specific test results are shown in Tables 2 and 3:

[0167] (1) Haze: measured according to the method in GB / T 2410-2008;

[0168] (2) Tear strength: measured according to the method in GB / T 529-2008;

[0169] (3) Heat seal strength: measured according to the method in GB / T 22638.7-2008;

[0170] The heat seal strength was tested by heat-bonding the cast film and the polypropylene cover material for 120 seconds at a temperature of 95°C and a pressure of 2 MPa.

[0171] Table 1

[0172] Vinyl acetate structural unit content (wt%) Melt index (g / 10min) J1 9.1 7.2 J2 18.5 3.6 DJ1 32.4 14.7 DJ2 9.3 1.8

[0173] Table 2

[0174] Vinyl acetate structural unit content (wt%) Melt index (g / 10min) Haze (%) A1 5.1 8.2 19.3 A2 3.1 8.2 20.4 A3 5.9 6.7 18.9 A4 5.9 6.4 21.0 A5 6.0 9.2 19.6 A6 7.0 9.4 21.5 A7 5.6 7.4 20.9 DA1 2.8 21.1 9.2 DA2 6.8 7.5 45.7 DA3 25.3 11.4 25.6 DA4 7.2 5.8 30.3 DA5 5.9 6.9 26.9 DA6 5.8 5.3 27.1 DA7 6.7 8.9 28.4

[0175] Table 3

[0176] Tear strength (KN / m) Heat seal strength (N / 15mm) A1 0.11 6.5 A2 0.16 7.4 A3 0.20 5.9 A4 0.15 7.3 A5 0.17 8.2 A6 0.21 7.8 A7 0.19 8.6 DA1 1.51 16.2 DA2 0.46 18.3 DA3 1.56 21.9 DA4 2.37 15.6 DA5 2.51 23.7 DA6 2.78 20.4 DA7 1.95 25.7

[0177] It can be seen from the results in Table 1 that the material prepared by using the composition provided by the present invention has the characteristics of low heat sealing temperature, good thermal adhesion and easy tearing when used as an easy-to-tear material.

[0178] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A composition for preparing an easy-to-tear material, characterized in that: The composition contains the following components: Ethylene vinyl acetate copolymer, polyethylene, tackifiers, lubricants, dispersants and antioxidants; Based on the total weight of the composition, the content of the ethylene-vinyl acetate copolymer is 40-80wt%, the content of the polyethylene is 14-50wt%, the content of the tackifier is 1-10wt%, the content of the lubricant is 0.01-0.5wt%, the content of the dispersant is 0.01-0.5wt%, and the content of the antioxidant is 0.05-0.5wt%; The density of the polyethylene is 0.918-0.922 g / cm 3 , the melt index at 190℃ under a load of 2.16kg is 1-10g / 10min; The ethylene-vinyl acetate copolymer is prepared by a method comprising the following steps: In the presence of an organic peroxide, ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain an ethylene-vinyl acetate copolymer melt; and extruding and granulating the ethylene-vinyl acetate copolymer melt I; The polymerization reaction conditions include: temperature of 190-310°C and pressure of 260-320 MPa; The feed rate of the ethylene monomer is 15-19 t / h; the pumping speed of the vinyl acetate monomer is 100-1000 rpm.

2. The composition according to claim 1, wherein The feed rate of the organic peroxide is 2-4 kg / h; and / or, The conditions of the extrusion granulation I include: a temperature of 170-210° C. and a rotation speed of 200-500 rpm.

3. The composition according to claim 1 or 2, wherein The organic peroxide is at least one selected from the group consisting of tert-butyl perbenzoate, tert-butyl perbenzoate, tert-butyl peroxide-2-ethylhexyl ester, tert-butyl peroxide pivalate, and tert-butyl peroxide neodecanoate.

4. The composition according to any one of claims 1 to 3, wherein The vinyl acetate structural unit content of the ethylene-vinyl acetate copolymer is 6-28 wt %; preferably 8-20 wt %; and / or, The ethylene-vinyl acetate copolymer has a melt index of 2-15 g / 10 min at 190° C. and under a load of 2.16 kg.

5. The composition according to any one of claims 1 to 4, wherein The tackifier is selected from at least one of rosin resin, C5 petroleum resin and C9 petroleum resin; and / or, The lubricant is selected from at least one of oleamide and erucamide.

6. The composition according to any one of claims 1 to 5, wherein The dispersant is selected from at least one of silicon oxide, zinc stearate and polyethylene glycol; preferably polyethylene glycol; and / or, The antioxidant is selected from at least one of hindered phenol antioxidants, aromatic amine antioxidants and auxiliary antioxidants.

7. A method for preparing an easily tearable material, characterized in that: The method is carried out using the composition according to any one of claims 1 to 6, comprising: Ethylene-vinyl acetate copolymer, polyethylene, a tackifier, a lubricant, a dispersant and an antioxidant are mixed and then subjected to extrusion granulation II to obtain pellets; and the pellets are subjected to a casting film forming process.

8. The method according to claim 7, wherein: The mixing method includes: first performing low-speed mixing and then performing high-speed mixing; and / or, The low-speed mixing conditions include: stirring at a speed of 200-600 rpm, a temperature of 25-65° C., and a time of 1-3 min; and / or, The high-speed mixing conditions include: stirring at a speed of 1000-1500 rpm, a temperature of 40-60° C., and a time of 1-3 minutes.

9. The method according to claim 7 or 8, wherein The conditions of the extrusion granulation II include: a temperature of 150-200° C. and a rotation speed of 150-300 rpm; and / or, The conditions of the tape casting film forming process include: a temperature of 180-210°C.

10. The easily tearable material prepared by the method according to any one of claims 7 to 9.