Composition for preparing thin-film material, thin-film material and preparation method and application of thin-film material

Abstract

The invention relates to the field of high polymer materials, and discloses a composition for preparing a thin film material, the thin film material as well as a preparation method and application of the thin film material. The composition comprises the following components: an ethylene-vinyl acetate copolymer, a light stabilizer and an antioxidant, relative to 100 parts by weight of the ethylene-vinyl acetate copolymer, the content of the light stabilizer is 0.05 to 0.2 part by weight, and the content of the antioxidant is 0.01 to 0.5 part by weight. The material prepared from the composition provided by the invention is good in anti-aging performance, low in yellow index and high in transmittance.

Description

Technical Field

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

[0002] Ultraviolet rays in sunlight are the primary cause of aging in polymer materials. Although UV rays only account for about 5% of sunlight, they pack a significant amount of energy. When absorbed by polymer products, UV rays can trigger self-oxidation and degradation, disrupting chemical bonds and causing them to break and crosslink. This can lead to changes in the appearance and physical and mechanical properties of polymer products, such as color, and deteriorate, reducing strength and shortening lifespan.

[0003] Light stabilizers have different functions due to their different structures and types. Some can shield, reflect or absorb ultraviolet rays and convert them into harmless heat energy; some can quench the excited state of molecules or groups excited by ultraviolet rays, returning them to the ground state, eliminating or slowing down the possibility of photooxidation-reduction reactions; some can capture free radicals generated by photooxidation-reduction, thereby preventing free radical reactions that cause product aging and protecting products from ultraviolet damage.

[0004] To effectively prevent or slow down photoaging in industry, antioxidants and light stabilizers are often used in combination. These antioxidants are hindered phenols or amines, which react with peroxide free radicals to form chromophores, making the material prone to yellowing and reducing visible light transmittance. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a material that has good anti-aging properties and also has a low yellowness index and a high transmittance.

[0006] In order to achieve the above object, the first aspect of the present invention provides a composition for preparing a thin film material, the composition comprising the following components:

[0007] Ethylene vinyl acetate copolymer, light stabilizer and antioxidant;

[0008] Relative to 100 parts by weight of the ethylene-vinyl acetate copolymer, the content of the light stabilizer is 0.05-0.2 parts by weight, and the content of the antioxidant is 0.01-0.5 parts by weight;

[0009] The ethylene-vinyl acetate copolymer is prepared by a method comprising the following steps:

[0010] In the presence of an organic peroxide, ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain a mixture I; the polymerization reaction conditions include: a temperature of 190-310° C., a pressure of 260-320 MPa; and an input temperature of the ethylene monomer of 20-45° C.;

[0011] Under a pressure of 20-40 MPa, the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0012] Under a pressure of 0.05-0.15 MPa, the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0013] Extruding and granulating the ethylene-vinyl acetate copolymer melt I;

[0014] The organic peroxide is a combination of peroxide A, peroxide B and peroxide C in a weight ratio of 1:1-1.5:1-1.5;

[0015] The peroxide A is a peroxide having a decomposition temperature of less than 90° C. with a half-life of 0.1 h;

[0016] The peroxide B is a peroxide with a decomposition temperature of 90-140° C. and a half-life of 0.1 h;

[0017] The peroxide C is a peroxide having a decomposition temperature higher than 140° C. with a half-life of 0.1 h.

[0018] The second aspect of the present invention provides a method for preparing a thin film material, which is performed using the composition described in the first aspect, comprising:

[0019] Ethylene-vinyl acetate copolymer, light stabilizer and antioxidant are mixed and then extruded and granulated II to obtain pellets; and the pellets are subjected to a casting film forming process.

[0020] The third aspect of the present invention provides a thin film material prepared by the method described in the second aspect.

[0021] The present invention uses an ethylene-vinyl acetate copolymer with low crystallinity obtained by polymerization in a tubular reactor in the presence of a specific initiator under high temperature and high pressure conditions, and combines it with a light stabilizer and an antioxidant with a specific content to prepare a non-toxic and environmentally friendly material with good anti-aging performance, a low yellow index and a high transmittance. DETAILED DESCRIPTION

[0022] 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.

[0023] As mentioned above, the first aspect of the present invention provides a composition for preparing a thin film material, the composition comprising the following components:

[0024] Ethylene vinyl acetate copolymer, light stabilizer and antioxidant;

[0025] Relative to 100 parts by weight of the ethylene-vinyl acetate copolymer, the content of the light stabilizer is 0.05-0.2 parts by weight, and the content of the antioxidant is 0.01-0.5 parts by weight;

[0026] The ethylene-vinyl acetate copolymer is prepared by a method comprising the following steps:

[0027] In the presence of an organic peroxide, ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor to obtain a mixture I; the polymerization reaction conditions include: a temperature of 190-310° C., a pressure of 260-320 MPa; and an input temperature of the ethylene monomer of 20-45° C.;

[0028] Under a pressure of 20-40 MPa, the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0029] Under a pressure of 0.05-0.15 MPa, the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0030] Extruding and granulating the ethylene-vinyl acetate copolymer melt I;

[0031] The organic peroxide is a combination of peroxide A, peroxide B and peroxide C in a weight ratio of 1:1-1.5:1-1.5;

[0032] The peroxide A is a peroxide having a decomposition temperature of less than 90° C. with a half-life of 0.1 h;

[0033] The peroxide B is a peroxide with a decomposition temperature of 90-140° C. and a half-life of 0.1 h;

[0034] The peroxide C is a peroxide having a decomposition temperature higher than 140° C. with a half-life of 0.1 h.

[0035] Preferably, the peroxide A is selected from at least one of di(2-ethylhexyl) peroxydicarbonate (Trigonox EHP-C75) and tert-butyl peroxyneodecanoate.

[0036] Preferably, the peroxide B is selected from at least one of tert-butyl peroxypivalate and tert-butyl peroxy-2-ethylhexanoate.

[0037] Preferably, the peroxide C is at least one selected from tert-butyl peroxyacetate, tert-butyl perbenzoate, and di-tert-butyl peroxide.

[0038] Preferably, the light stabilizer is at least one of ultraviolet absorbers.

[0039] More preferably, the light stabilizer is a combination of a benzophenone ultraviolet absorber and a benzotriazole ultraviolet absorber in a weight ratio of 1:1-2. The inventors of the present invention have found that under this preferred embodiment, the prepared material has better ultraviolet resistance.

[0040] Preferably, the benzophenone-based UV absorber is at least one selected from 2-hydroxy-4-n-octyloxybenzophenone (UV-531), 2-hydroxy-4-methoxybenzophenone (UV-9) and 2,4-dihydroxybenzophenone (UV-0).

[0041] Preferably, the benzotriazole ultraviolet absorber is selected from at least one of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), 2-(2-hydroxy-5-methylphenyl)benzotriazole (UV-P) and 2-(2-hydroxy-3-tert-butyl-methylphenyl)-5-chlorobenzotriazole (UV-326).

[0042] Particularly preferably, the light stabilizer is a combination of 2-hydroxy-4-n-octyloxybenzophenone and 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole in a weight ratio of 1:1-1.5. The inventors of the present invention have found that in this preferred embodiment, the prepared material not only has better UV resistance but also better alcohol resistance.

[0043] Preferably, the feed rate of the ethylene monomer is 10-20 t / h.

[0044] Preferably, the pumping speed of the vinyl acetate monomer is 200-800 rpm.

[0045] Preferably, the feed rate of the organic peroxide is 2-4 kg / h.

[0046] Preferably, the conditions of the extrusion granulation I include: a temperature of 150-250° C. and a rotation speed of 150-500 rpm.

[0047] Preferably, the molecular weight distribution of the ethylene-vinyl acetate copolymer is 5-10, and the weight average molecular weight is 50,000-150,000.

[0048] More preferably, the molecular weight distribution of the ethylene-vinyl acetate copolymer is 5-8, and the weight average molecular weight is 80,000-150,000. The inventors of the present invention have found that under this preferred condition, the prepared material has better optical properties (higher light transmittance).

[0049] Preferably, the vinyl acetate structural unit content of the ethylene-vinyl acetate copolymer is 10-20 wt%.

[0050] Preferably, the ethylene-vinyl acetate copolymer has a melt index of 3-15 g / 10 min at 190° C. and a load of 2.16 kg.

[0051] According to a preferred embodiment, the antioxidant is selected from at least one of hindered phenol antioxidants, aromatic amine antioxidants and auxiliary antioxidants.

[0052] 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).

[0053] More preferably, the aromatic amine antioxidant is selected from at least one of diphenylamine, p-phenylenediamine and dihydroquinoline compounds.

[0054] Preferably, the auxiliary antioxidant is selected from at least one phosphite antioxidant.

[0055] More preferably, the phosphite antioxidant is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite (Antioxidant 168), bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (Antioxidant 242), bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate (Antioxidant PEP-36), bis(2,4-dicumylphenyl) pentaerythritol diphosphite (Doverphos S-9228), and tetrakis(2,4-di-tert-butyloctaalkoxy-4,4-biphenyl) phosphate (Mark HP-10).

[0056] As mentioned above, the second aspect of the present invention provides a method for preparing a thin film material, which is performed using the composition described in the first aspect, comprising:

[0057] Ethylene-vinyl acetate copolymer, light stabilizer and antioxidant are mixed and then extruded and granulated II to obtain pellets; and the pellets are subjected to a casting film forming process.

[0058] According to another 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 this preferred embodiment can improve the compatibility between the raw materials in the extrusion granulation II process and make the auxiliary agent more evenly dispersed.

[0059] According to a particularly preferred embodiment, 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.

[0060] According to another particularly preferred embodiment, 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.

[0061] Preferably, the conditions of the extrusion granulation II include: a temperature of 150-200° C. and a rotation speed of 150-300 rpm.

[0062] Preferably, the conditions of the tape casting film forming process include: a temperature of 180-210°C.

[0063] As mentioned above, the third aspect of the present invention provides a thin film material prepared by the method described in the second aspect.

[0064] The present invention will be described in detail below through examples.

[0065] In the following examples, unless otherwise specified, all raw materials used are commercially available.

[0066] In the following examples, the test methods for each characteristic parameter are as follows:

[0067] Weight average molecular weight and molecular weight distribution: tested by gel permeation chromatography (GPC);

[0068] Vinyl acetate structural unit content: determined according to the method in SH / T 1591-1994;

[0069] Melt index: measured according to the method in GB / T3682-2000.

[0070] Organic peroxides:

[0071] Peroxide A: Trigonox EHP-C75, decomposition temperature of 83°C with a half-life of 0.1 h;

[0072] Peroxide B: tert-butyl peroxy-2-ethylhexanoate, with a decomposition temperature of 113°C with a half-life of 0.1 h;

[0073] Peroxide C: tert-butyl perbenzoate, with a decomposition temperature of 142°C with a half-life of 0.1 h;

[0074] Light stabilizer:

[0075] Light stabilizer I: benzophenone, UV-531;

[0076] Light stabilizer II-1: benzotriazole, UV-327;

[0077] Light stabilizer II-2: benzotriazole, UV-P;

[0078] Light stabilizer III: hindered amines, 2,2,6,6-tetramethyl-4-piperidinyl benzoate;

[0079] Antioxidants:

[0080] Antioxidant I: hindered phenols, antioxidant 1010;

[0081] Antioxidant II: Auxiliary antioxidant, phosphite, antioxidant 168.

[0082] Preparation Example 1

[0083] Ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor in the presence of an organic peroxide (a combination of peroxide A, peroxide B, and peroxide C in a weight ratio of 1:1.2:1.2) to produce a mixture I. The polymerization reaction conditions include: a temperature of 240° C., a pressure of 280 MPa, and an input temperature of the ethylene monomer of 25° C.

[0084] The feed rate of ethylene monomer was 15 t / h, the pump speed of vinyl acetate monomer was 300 rpm, and the feed rate of organic peroxide was 2.5 kg / h;

[0085] Under the conditions of a pressure of 30 MPa and a temperature of 250° C., the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0086] Under the conditions of a pressure of 0.10 MPa and a temperature of 250° C., the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0087] Extruding and granulating the ethylene-vinyl acetate copolymer melt I to obtain ethylene-vinyl acetate copolymer J1;

[0088] The conditions for extrusion granulation I were as follows: the extrusion was carried out in a twin-screw machine at a temperature of 250° C. and a rotation speed of 500 rpm.

[0089] Preparation Example 2

[0090] Ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor in the presence of an organic peroxide (a combination of peroxide A, peroxide B, and peroxide C in a weight ratio of 1:1.2:1.0) to produce a mixture I. The polymerization reaction conditions include: a temperature of 245° C., a pressure of 275 MPa, and an input temperature of the ethylene monomer of 30° C.

[0091] The feed rate of ethylene monomer was 15 t / h, the pump speed of vinyl acetate monomer was 400 rpm, and the feed rate of organic peroxide was 3 kg / h;

[0092] Under the conditions of a pressure of 30 MPa and a temperature of 250° C., the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0093] Under the conditions of a pressure of 0.10 MPa and a temperature of 250° C., the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0094] Extruding and granulating the ethylene-vinyl acetate copolymer melt I to obtain ethylene-vinyl acetate copolymer J2;

[0095] The conditions for extrusion granulation I were as follows: the extrusion was carried out in a twin-screw machine at a temperature of 250° C. and a rotation speed of 500 rpm.

[0096] Preparation Example 3

[0097] Ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor in the presence of an organic peroxide (a combination of peroxide A, peroxide B, and peroxide C in a weight ratio of 1:1.2:1.0) to produce a mixture I. The polymerization reaction conditions include: a temperature of 245° C., a pressure of 280 MPa, and an input temperature of the ethylene monomer of 30° C.

[0098] The feed rate of ethylene monomer was 10 t / h, the pump speed of vinyl acetate monomer was 300 rpm, and the feed rate of organic peroxide was 2.5 kg / h;

[0099] Under the conditions of a pressure of 30 MPa and a temperature of 250° C., the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0100] Under the conditions of a pressure of 0.10 MPa and a temperature of 250° C., the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0101] Extruding and granulating the ethylene-vinyl acetate copolymer melt I to obtain ethylene-vinyl acetate copolymer J3;

[0102] The conditions for extrusion granulation I were as follows: the extrusion was carried out in a twin-screw machine at a temperature of 250° C. and a rotation speed of 500 rpm.

[0103] Preparation Example 4

[0104] Ethylene monomer and vinyl acetate monomer are polymerized in a tubular reactor in the presence of an organic peroxide (a combination of peroxide A, peroxide B, and peroxide C in a weight ratio of 1:1.2:1.5) to produce a mixture I. The polymerization reaction conditions include: a temperature of 248° C., a pressure of 280 MPa, and an input temperature of the ethylene monomer of 30° C.

[0105] The feed rate of ethylene monomer was 18 t / h, the pump speed of vinyl acetate monomer was 400 rpm, and the feed rate of organic peroxide was 2.5 kg / h;

[0106] Under the conditions of a pressure of 30 MPa and a temperature of 250° C., the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling;

[0107] Under the conditions of a pressure of 0.10 MPa and a temperature of 250° C., the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling;

[0108] Extruding and granulating the ethylene-vinyl acetate copolymer melt I to obtain ethylene-vinyl acetate copolymer J4;

[0109] The conditions for extrusion granulation I were as follows: the extrusion was carried out in a twin-screw machine at a temperature of 250° C. and a rotation speed of 500 rpm.

[0110] Preparation Example 5

[0111] This preparation example was carried out using a method similar to that of Preparation Example 1, except that:

[0112] The organic peroxide is a combination of peroxide A, peroxide B and peroxide C in a weight ratio of 1:1.5:1.5;

[0113] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer J5.

[0114] Preparation Example 6

[0115] This preparation example was carried out using a method similar to that of Preparation Example 1, except that:

[0116] The feed rate of ethylene monomer is 20t / h;

[0117] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer J6.

[0118] Comparative Preparation Example 1

[0119] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0120] The organic peroxide is a combination of peroxide A, peroxide B and peroxide C in a weight ratio of 1:2.0:2.0;

[0121] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ1.

[0122] Comparative Preparation Example 2

[0123] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0124] The organic peroxide is a combination of peroxide A and peroxide B in a weight ratio of 1:1.2;

[0125] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ2.

[0126] Comparative Preparation Example 3

[0127] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0128] The organic peroxide is a combination of peroxide A and peroxide C in a weight ratio of 1:1.2;

[0129] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ3.

[0130] Comparative Preparation Example 4

[0131] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0132] The input temperature of ethylene monomer was 47°C;

[0133] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ4.

[0134] Comparative Preparation Example 5

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

[0136] The polymerization temperature was 185°C and the pressure was 240 MPa;

[0137] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ5.

[0138] Comparative Preparation Example 6

[0139] This comparative preparation example was carried out in a manner similar to that of Preparation Example 1, except that:

[0140] Without performing the second separation, the mixture II is directly subjected to extrusion granulation I;

[0141] The remaining conditions were the same as those in Preparation Example 1 to prepare ethylene-vinyl acetate copolymer DJ6.

[0142] Example 1

[0143] The formula of the film material is as follows:

[0144] 100 parts by weight of ethylene-vinyl acetate copolymer J1, 0.05 parts by weight of light stabilizer I and 0.05 parts by weight of light stabilizer II-1, 0.1 parts by weight of antioxidant I and 0.05 parts by weight of antioxidant II;

[0145] The method for preparing the thin film material is as follows:

[0146] Ethylene-vinyl acetate copolymer, light stabilizer 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;

[0147] The low-speed mixing conditions are: stirring under the conditions of 500 rpm, 40°C, and 3 min;

[0148] 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;

[0149] 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;

[0150] The pellet A1 is subjected to a casting film forming process to obtain a cast film S1 with a thickness of 400 μm;

[0151] 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.

[0152] Example 2

[0153] The formula of the film material is as follows:

[0154] 100 parts by weight of ethylene-vinyl acetate copolymer J2, 0.05 parts by weight of light stabilizer I, and 0.1 parts by weight of antioxidant I;

[0155] The method for preparing the thin film material is as follows:

[0156] Ethylene-vinyl acetate copolymer, light stabilizer and antioxidant are first mixed at a low speed, then mixed at a high speed, and then extruded into granules II to obtain granules A2;

[0157] The low-speed mixing conditions are: stirring under the conditions of 500 rpm, 40°C, and 3 min;

[0158] 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;

[0159] 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;

[0160] The pellet A2 is subjected to a casting film forming process to obtain a cast film S2 with a thickness of 400 μm;

[0161] 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.

[0162] Example 3

[0163] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0164] The ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer J3, and the amount of light stabilizer I is 0.1 parts by weight;

[0165] The remaining conditions were the same as those in Example 2, and pellets A3 and cast film S3 were prepared.

[0166] Example 4

[0167] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0168] The amount of light stabilizer I is 0.1 parts by weight, and the antioxidant is 0.1 parts by weight of antioxidant I and 0.1 parts by weight of antioxidant II;

[0169] The remaining conditions were the same as those in Example 2, and pellets A4 and cast film S4 were prepared.

[0170] Example 5

[0171] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0172] The ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer J3, and the antioxidants are 0.05 parts by weight of antioxidant I and 0.05 parts by weight of antioxidant II;

[0173] The remaining conditions were the same as those in Example 2, and pellets A5 and cast film S5 were prepared.

[0174] Example 6

[0175] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0176] The ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer J4, the amount of light stabilizer I is 0.1 parts by weight, and the antioxidants are 0.1 parts by weight of antioxidant I and 0.1 parts by weight of antioxidant II;

[0177] The remaining conditions were the same as those in Example 2, and pellets A6 and cast film S6 were prepared.

[0178] Example 7

[0179] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0180] The light stabilizer is 0.05 parts by weight of light stabilizer I and 0.05 parts by weight of light stabilizer III;

[0181] The remaining conditions were the same as those in Example 1, and pellets A7 and cast film S7 were prepared.

[0182] Example 8

[0183] This embodiment is carried out in a similar manner to that of embodiment 1, except that:

[0184] The light stabilizer is 0.05 parts by weight of light stabilizer I and 0.05 parts by weight of light stabilizer II-2;

[0185] The remaining conditions were the same as those in Example 1, and pellets A8 and cast film S8 were prepared.

[0186] Example 9

[0187] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0188] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer J5;

[0189] The remaining conditions were the same as those in Example 2, and pellets A9 and cast film S9 were prepared.

[0190] Example 10

[0191] This embodiment is carried out in a similar manner to that of embodiment 2, except that:

[0192] The ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer J6, the light stabilizer is 0.1 parts by weight of light stabilizer I, and the antioxidants are 0.1 parts by weight of antioxidant I and 0.05 parts by weight of antioxidant II;

[0193] The remaining conditions were the same as those in Example 2, and pellets A10 and cast film S10 were prepared.

[0194] Comparative Example 1

[0195] This comparative example was carried out in a manner similar to that of Example 2, except that:

[0196] The antioxidant is 1 part by weight of Antioxidant I;

[0197] The remaining conditions were the same as those in Example 2, and pellets DA1 and cast film DS1 were prepared.

[0198] Comparative Example 2

[0199] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0200] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ1;

[0201] The remaining conditions were the same as those in Example 1, and pellets DA2 and cast film DS2 were prepared.

[0202] Comparative Example 3

[0203] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0204] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ2;

[0205] The remaining conditions were the same as those in Example 1, and pellets DA3 and cast film DS3 were prepared.

[0206] Comparative Example 4

[0207] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0208] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ3;

[0209] The remaining conditions were the same as those in Example 1, and pellets DA4 and cast film DS4 were prepared.

[0210] Comparative Example 5

[0211] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0212] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ4;

[0213] The remaining conditions were the same as those in Example 1, and pellets DA5 and cast film DS5 were prepared.

[0214] Comparative Example 6

[0215] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0216] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ5;

[0217] The remaining conditions were the same as those in Example 1, and pellets DA6 and cast film DS6 were prepared.

[0218] Comparative Example 7

[0219] This comparative example was carried out in a manner similar to that of Example 1, except that:

[0220] Ethylene-vinyl acetate copolymer is ethylene-vinyl acetate copolymer DJ6;

[0221] The remaining conditions were the same as those in Example 1, and pellets DA7 and cast film DS7 were prepared.

[0222] Test Case

[0223] The relevant parameters of the ethylene-vinyl acetate copolymers prepared in the preparation examples and comparative preparation examples are shown in Table 1;

[0224] 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:

[0225] (1) Hydrophilicity (water contact angle): measured according to the method in GB / T 30693-2014;

[0226] (2) Haze: measured according to the method in GB / T 2410-2008;

[0227] (3) Transmittance: measured according to the method in GB / T 2410-2008;

[0228] (4) Yellowness index: measured according to the method in HG / T 3862-2006, where the power of the UV light is 0.76 W and the concentration of the alcohol is 75 vol%;

[0229] (5) Tensile strength: measured according to the method in GB / T 1040.2-2006, where the heat aging condition is 60°C for 240 h.

[0230] Table 1

[0231]

[0232] Table 2

[0233] Hydrophilicity (°) Haze (%) Light transmittance (%) A1 98.6 1.5 92.0 A2 94.1 3.2 91.5 A3 95.6 3.2 89.7 A4 96.5 2.6 92.4 A5 96.2 1.0 89.7 A6 97.9 2.6 91.5 A7 98.1 3.0 90.5 A8 97.3 2.9 91.6 A9 96.9 2.4 90.3 A10 105.8 11.0 80.4 DA1 106.9 15.0 79.3 DA2 104.6 9.6 82.6 DA3 105.2 8.9 83.1 DA4 107.1 10.5 79.5 DA5 108.4 9.8 84.1 DA6 105.9 10.1 80.9 DA7 106.2 11.4 84.2

[0234] Table 3

[0235]

[0236]

[0237] It can be seen from the results in Table 2 and Table 3 that the material prepared by using the composition provided by the present invention not only has good anti-aging performance, but also has a low yellow index and high transmittance.

[0238] The preferred embodiments of the present invention are 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 the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. A composition for preparing a thin film material, characterized in that: The composition contains the following components: Ethylene vinyl acetate copolymer, light stabilizer and antioxidant; Relative to 100 parts by weight of the ethylene-vinyl acetate copolymer, the content of the light stabilizer is 0.05-0.2 parts by weight, and the content of the antioxidant is 0.01-0.5 parts by weight; 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 a mixture I; the polymerization reaction conditions include: a temperature of 190-310° C., a pressure of 260-320 MPa; and an input temperature of the ethylene monomer of 20-45° C.; Under a pressure of 20-40 MPa, the mixture I is subjected to a first separation to obtain a mixture II and ethylene monomer for recycling; Under a pressure of 0.05-0.15 MPa, the mixture II is subjected to a second separation to obtain an ethylene-vinyl acetate copolymer melt and ethylene monomer for recycling; Extruding and granulating the ethylene-vinyl acetate copolymer melt I; The organic peroxide is a combination of peroxide A, peroxide B and peroxide C in a weight ratio of 1:1-1.5:1-1.5; The peroxide A is a peroxide having a decomposition temperature of less than 90° C. with a half-life of 0.1 h; The peroxide B is a peroxide with a decomposition temperature of 90-140° C. and a half-life of 0.1 h; The peroxide C is a peroxide having a decomposition temperature higher than 140° C. with a half-life of 0.1 h.

2. The composition according to claim 1, wherein The light stabilizer is at least one of the ultraviolet absorbers; and / or, The light stabilizer is a combination of a benzophenone ultraviolet absorber and a benzotriazole ultraviolet absorber in a weight ratio of 1:1-2; and / or, The benzophenone-based ultraviolet absorber is selected from at least one of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone and 2,4-dihydroxybenzophenone; and / or, The benzotriazole ultraviolet absorber is selected from at least one of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole and 2-(2-hydroxy-3-tert-butyl-methylphenyl)-5-chlorobenzotriazole.

3. The composition according to claim 1 or 2, wherein The feed rate of the ethylene monomer is 10-20 t / h; and / or, The pumping speed of the vinyl acetate monomer is 200-800 rpm; and / or, The feed rate of the organic peroxide is 2-4 kg / h.

4. The composition according to any one of claims 1 to 3, wherein The conditions of the extrusion granulation I include: a temperature of 150-250° C. and a rotation speed of 150-500 rpm.

5. The composition according to any one of claims 1 to 4, wherein The molecular weight distribution of the ethylene-vinyl acetate copolymer is 5-10, and the weight average molecular weight is 50,000-150,000; and / or, The vinyl acetate structural unit content of the ethylene-vinyl acetate copolymer is 10-20 wt%; and / or, The ethylene-vinyl acetate copolymer has a melt index of 3-15 g / 10 min at 190° C. and a load of 2.16 kg.

6. The composition according to any one of claims 1 to 5, wherein The antioxidant is selected from at least one of hindered phenol antioxidants, aromatic amine antioxidants and auxiliary antioxidants; and / or, The auxiliary antioxidant is selected from at least one phosphite antioxidant.

7. A method for preparing a thin film 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, light stabilizer and antioxidant are mixed and then extruded and granulated 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. A film material prepared by the method according to any one of claims 7 to 9.

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