PVC resin, preparation method and application thereof, PVC film raw material composition, PVC film and preparation method thereof

Abstract

The invention relates to the field of synthetic resin preparation, in particular to PVC resin, a preparation method and application thereof, a PVC film raw material composition, a PVC film and a preparation method of the PVC film. The PVC resin comprises a structural unit a provided by vinyl chloride, a structural unit b provided by isodecyl acrylate and a structural unit c provided by ethoxylated trimethylolpropane triacrylate; the PVC resin is subjected to graft copolymerization through the isodecyl acrylate, the ethoxylated trimethylolpropane triacrylate and the vinyl chloride monomer to form a dense three-dimensional net-shaped structure, the dense three-dimensional net-shaped structure can form proper roughness on the surface of a film product, adhesion of the film and a gluing layer is facilitated, and when the PVC resin is used for preparing the PVC film, the PVC film has the advantages of being good in cold resistance, good in heat resistance, good in weather resistance and the like. The packaging film is suitable for packaging films and gluing packaging in cold regions.

Description

Technical Field

[0001] The invention relates to the field of synthetic resin preparation, and in particular to a PVC resin and a preparation method and application thereof, as well as a PVC film raw material composition and a PVC film and a preparation method thereof. Background Art

[0002] PVC film has the advantages of being soft, wear-resistant, high in mechanical properties, easy to process, and cost-effective, and is widely used in offices, packaging, and gluing. However, the cold resistance of PVC film is poor, the surface is smooth, and it is difficult for the glue layer to form a strong adhesion with the PVC film.

[0003] CN201680077897.5 discloses a composition for roughening the surface of a resin, providing a means for achieving a surface roughening method by adding and post-treating the resin composition more conveniently than before, wherein the surface roughening method is used to modify the surface layer of a resin molded body to form a surface layer such as a coating and plating or to exhibit functions brought about by the surface shape, wherein the composition contains an aliphatic polycarbonate and an alkali metal compound, wherein the alkali metal compound is at least one selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate and an alkali metal carboxylate. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of poor cold resistance, smooth surface and difficulty in forming strong adhesion between the glue layer and the PVC film in the prior art, and to provide a PVC resin and a preparation method and application thereof, as well as a PVC film raw material composition and a PVC film and a preparation method thereof. The obtained PVC film has the advantages of good cold resistance and the surface roughness of the product is suitable for glue coating, and is suitable for packaging film and glue-coated packaging in cold areas.

[0005] According to the existing literature, PVC films are currently mainly prepared by cast film, blow molding, and calendering, each with its own advantages and disadvantages. Cast film is prone to degradation of PVC materials, and the PVC film produced by blow molding has poor thickness uniformity, and soft products are prone to film breakage by blow molding. The calendering method requires high equipment investment, and the thickness uniformity of the product is more complicated to adjust.

[0006] The present invention proposes for the first time to use isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride monomer for graft copolymerization to form a dense three-dimensional network structure. This dense three-dimensional network structure can form a suitable roughness on the surface of the film product, which is beneficial to the adhesion of the film to the adhesive layer.

[0007] The present invention aims to improve the cold resistance of PVC film by graft copolymerizing isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride to form a soft molecular chain, so that the film can be used in cold environments. The surface roughness of the obtained PVC resin product is suitable for gluing, and can be used for packaging film and glue-coated packaging in cold areas.

[0008] In order to achieve the above-mentioned object, the present invention provides a PVC resin on one hand, which comprises: a structural unit a provided by vinyl chloride, a structural unit b provided by isobutyl acrylate and a structural unit c provided by ethoxylated trimethylolpropane triacrylate.

[0009] The second aspect of the present invention provides a method for preparing the PVC resin of the present invention, the method comprising:

[0010] In the presence of an initiator, isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride are copolymerized.

[0011] The third aspect of the present invention provides use of the PVC resin of the present invention in film preparation.

[0012] A fourth aspect of the present invention provides a PVC film raw material composition, which comprises the PVC resin described in the present invention.

[0013] A fifth aspect of the present invention provides a method for preparing a PVC resin film, the method comprising: molding a PVC film raw material composition, wherein the PVC film raw material composition comprises the composition described in the present invention.

[0014] Through the above technical solution, the present invention has the following beneficial effects:

[0015] The PVC resin of the present invention contains structural unit a provided by vinyl chloride, structural unit b provided by isodecyl acrylate and structural unit c provided by ethoxylated trimethylolpropane triacrylate. The PVC film prepared therefrom has good cold resistance and the surface roughness of the product is suitable for glue coating, and is suitable for packaging film and glue coating packaging in cold areas. DETAILED DESCRIPTION

[0016] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[0017] The present invention provides a PVC resin, which comprises: a structural unit a provided by vinyl chloride, a structural unit b provided by isodecyl acrylate, and a structural unit c provided by ethoxylated trimethylolpropane triacrylate. The PVC film prepared from the PVC resin of the present invention has the advantages of good cold resistance and a surface roughness suitable for gluing, and is suitable for packaging film and gluing packaging in cold regions.

[0018] In the present invention, the structural formula of isodecyl acrylate is as follows:

[0019]

[0020] In the present invention, the structural unit b is formed by opening the olefinic bond in isodecyl acrylate.

[0021] In the present invention, the structural formula of ethoxylated trimethylolpropane triacrylate is as follows,

[0022]

[0023] In the present invention, the structural unit c is formed by opening the olefinic bonds in ethoxylated trimethylolpropane triacrylate under copolymerization conditions and connecting with other structural units.

[0024] According to a preferred embodiment of the present invention, based on 100 wt % of vinyl chloride monomer, the mass of the structural unit b provided by isocyanate acrylate in the PVC resin is 0.2-0.4 wt % of the mass of the vinyl chloride monomer.

[0025] According to a preferred embodiment of the present invention, based on 100 wt % of the vinyl chloride monomer, the mass of the structural unit c provided by ethoxylated trimethylolpropane triacrylate in the PVC resin is 0.2-0.4 wt % of the mass of the vinyl chloride monomer.

[0026] In the present invention, the PVC resin has a three-dimensional network structure, which can form a suitable roughness on the surface of the film product, which is conducive to the adhesion of the film and the adhesive layer.

[0027] All resins having the aforementioned characteristics of the present invention can be used in the present invention, and there is no special requirement for their preparation methods. According to the present invention, a preparation method of PVC resin is provided, which comprises: copolymerizing isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride in the presence of an initiator.

[0028] In the present invention, there is no special requirement for the copolymerization method. According to a preferred embodiment of the present invention, the copolymerization method comprises: after mixing deionized water, isobutyl acrylate, ethoxylated trimethylolpropane triacrylate, a dispersant, an initiator, and vinyl chloride for copolymerization, adding a terminator to terminate the reaction, separating the solid and the liquid, and drying; preferably, the method comprises: (a) mixing deionized water, isobutyl acrylate, ethoxylated trimethylolpropane triacrylate, a dispersant, and an initiator; (b) adding vinyl chloride to the mixed materials for copolymerization; (c) adding a terminator to terminate the reaction after the copolymerization, separating the solid and the liquid, and drying.

[0029] In the present invention, the solid-liquid separation in step (c) is centrifugal dehydration, which can be performed with reference to the prior art, and the present invention will not elaborate on it here.

[0030] In the present invention, the drying conditions in step (c) include drying in an oven at 50-80° C., which can be carried out by referring to the prior art.

[0031] In the present invention, the amounts of the isobutyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride monomer can be selected accordingly according to the contents of the required structural unit a, structural unit b and structural unit c in the PVC resin.

[0032] In the present invention, the isobutyl acrylate and ethoxylated trimethylolpropane triacrylate can cooperate with the vinyl chloride monomer to form a dense three-dimensional network structure. This dense three-dimensional network structure can form a suitable roughness on the surface of the film product, which is beneficial to the adhesion of the film to the adhesive layer.

[0033] In the present invention, there is no special requirement for the ratio of the mass of the deionized water to the total mass of isobutyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride monomer, as long as the aqueous phase suspension copolymerization reaction can proceed smoothly.

[0034] According to a preferred embodiment of the present invention, the ratio of the mass of water to the total mass of isobutyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride monomer is (1.4-2.1): 1. By adopting the above preferred embodiment, a dense three-dimensional network structure can be formed, which is used in the preparation of PVC film, and the cold resistance of the PVC film can be improved, so that the film can be used in cold environments.

[0035] According to a preferred embodiment of the present invention, the amount of the dispersant used is 0.09-0.14 wt % of the amount of vinyl chloride used.

[0036] According to a preferred embodiment of the present invention, the amount of the initiator used is 0.05-0.07 wt % of the amount of vinyl chloride used.

[0037] By adopting the above-mentioned preferred embodiment, the surface of the film product can form a suitable roughness, which is beneficial to the adhesion of the film and the adhesive layer.

[0038] In the present invention, there is no special requirement for the dispersant. According to a preferred embodiment of the present invention, the dispersant comprises at least one of polyvinyl alcohol dispersants, cellulose ethers, fatty alcohol polyoxyethylene ethers, gelatins and alkylphenol polyoxyethylene ethers, preferably a mixture of polyvinyl alcohol dispersants and cellulose ethers, and more preferably a mass ratio of polyvinyl alcohol dispersants to cellulose ethers of (0.91-1.43): (0.26-0.39). By adopting the aforementioned preferred embodiment, the surface of the membrane product can form a suitable roughness, which is conducive to the adhesion of the membrane to the adhesive layer.

[0039] In the present invention, there is no special requirement for the polyvinyl alcohol dispersant. According to a preferred embodiment of the present invention, the polyvinyl alcohol dispersant is selected from at least one of KH-20, L-9, S202, L-11, L-0 and 420, preferably a mixture of KH-20, L-9 and S202, and further preferably, the mass ratio of KH-20, L-9 and S202 in the mixture is (0.13-0.26): (0.52-0.78): (0.26-0.39). By adopting the above preferred embodiment, the surface of the film product can form a suitable roughness, which is conducive to the adhesion of the film to the adhesive layer.

[0040] In the present invention, there is no special requirement for the cellulose ethers. According to a preferred embodiment of the present invention, the cellulose ethers are preferably modified cellulose ethers, and the modified cellulose ethers are selected from at least one of E50 and FON50. In the present invention, E50 is used as an example in the examples, but the present invention is not limited to this scope. By adopting the above preferred embodiments, the surface of the film product can form a suitable roughness, which is conducive to the adhesion of the film to the adhesive layer.

[0041] In the present invention, there is no special requirement for the initiator. According to a preferred embodiment of the present invention, the initiator is selected from at least one of azobisisoheptanonitrile, diisobutyryl peroxide, isopropyl peroxyneodecanoate, bis(2-ethylhexyl peroxydicarbonate) and t-pentyl peroxyneodecanoate, preferably isopropyl peroxyneodecanoate, one or two of bis(2-ethylhexyl peroxydicarbonate); more preferably, it is a mixture of isopropyl peroxyneodecanoate and bis(2-ethylhexyl peroxydicarbonate, and more preferably, the mass ratio of isopropyl peroxyneodecanoate and bis(2-ethylhexyl peroxydicarbonate in the mixture is (0.52-0.65): (0.13-0.26). By adopting the above preferred embodiment, the surface of the membrane product can form a suitable roughness, which is conducive to the adhesion of the membrane to the adhesive layer.

[0042] In the present invention, there is no special requirement for the terminator. According to a preferred embodiment of the present invention, the terminator is selected from at least one of ATSC, DEHA and bisphenol A. In the present invention, DEHA is used as an example in the examples, but the present invention is not limited to this scope. By adopting the above preferred embodiments, the termination efficiency and the detoxication of the operating environment can be further improved.

[0043] In the present invention, when the reaction is carried out until the pressure in the kettle drops by 0.14 MPa from the maximum pressure value, a terminator is added to terminate the reaction.

[0044] In the present invention, there is no special requirement for the mixing conditions in step (a), as long as the purpose of the present invention is achieved.

[0045] According to a preferred embodiment of the present invention, the mixing temperature is 15-25°C.

[0046] According to a preferred embodiment of the present invention, the mixing time is 10-30 minutes.

[0047] By adopting the above-mentioned preferred embodiment, the surface of the film product can form a suitable roughness, which is beneficial to the adhesion of the film and the adhesive layer.

[0048] In the present invention, there is no special requirement for the copolymerization reaction conditions, as long as the purpose of the present invention is achieved.

[0049] According to a preferred embodiment of the present invention, the copolymerization temperature is 51-53°C.

[0050] According to a preferred embodiment of the present invention, the copolymerization pressure is 0.860-0.875 MPa.

[0051] According to a preferred embodiment of the present invention, the copolymerization time is 300-490 min.

[0052] By adopting the above-mentioned preferred embodiment, the surface used to prepare the film product can form a suitable roughness, which is conducive to the adhesion of the film and the adhesive layer.

[0053] The present invention provides application of the PVC resin of the present invention in film preparation.

[0054] The present invention provides a PVC film raw material composition, which comprises the PVC resin of the present invention.

[0055] According to a preferred embodiment of the present invention, the raw material composition contains: PVC resin, stabilizer, plasticizer and lubricant.

[0056] According to a preferred embodiment of the present invention, the mass ratio of the PVC resin, stabilizer, plasticizer and lubricant is 100:(5.0-7.0):(30-50):(5-10):(0.2-0.4).

[0057] According to a preferred embodiment of the present invention, the stabilizer in the examples is illustrated by calcium zinc heat stabilizer, but the present invention is not limited to this scope.

[0058] According to a preferred embodiment of the present invention, the plasticizer is a DOP plasticizer and / or a DOS plasticizer.

[0059] According to a preferred embodiment of the present invention, the lubricant in the examples is oxidized polyethylene wax as an example, but the present invention is not limited to this scope.

[0060] By adopting the above-mentioned preferred embodiment, the surface of the film product can form a suitable roughness, which is beneficial to the adhesion of the film and the adhesive layer.

[0061] The present invention provides a method for preparing a PVC film, which comprises: molding a PVC film raw material composition, wherein the PVC film raw material composition comprises the composition of the present invention.

[0062] According to a preferred embodiment of the present invention, the brittle temperature of the film is 35-40°C.

[0063] According to a preferred embodiment of the present invention, the thickness of the film is 0.7-1 μm.

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

[0065] The materials of the examples of the present invention were accurately weighed according to the formula in Table 1, and the materials of the comparative examples were accurately weighed according to the formula in Table 2. The pressure of the polymerization reaction was 0.87 MPa, and the time was 400 min.

[0066] Preparation of PVC resin: first add deionized water, isodecyl acrylate ISODA, ethoxylated trimethylolpropane triacrylate, four dispersants, and two initiators into a 5-liter polymerization kettle and stir at room temperature (temperature is 20°C) for 20 minutes, then add vinyl chloride monomer and stir for 15 minutes, and heat to 53°C to start polymerization. When the reaction is carried out until the pressure in the kettle drops by 0.14MPa from the maximum pressure value, add a terminator to terminate the reaction, discharge the material into a centrifuge for centrifugal dehydration, and dry the dehydrated wet material in an oven at 60°C.

[0067] Preparation of PVC resin film: 100 parts of the resin are mixed evenly with 6 parts of calcium zinc heat stabilizer (brand RUP-129C), 40 parts of plasticizer DOP, 10 parts of plasticizer DOS, 0.3 parts of oxidized polyethylene wax (brand AC-6A) and lubricant (brand OPE Wax OA2).

[0068] Test method: The composition was rolled into a sheet by double rolls, and the sheet was molded into a soft sheet with a thickness of 1.6 mm on a hot mold press. Samples were prepared on the sheet to test the low-temperature brittle temperature according to GB / T 5470-2008. The composition was rolled into a 70 μm thick film, and samples were taken from the film to test the surface roughness performance. The surface roughness was tested with a roughness tester and expressed as the arithmetic mean deviation Ra of the profile. The test results of low-temperature brittle temperature and roughness are shown in Table 3.

[0069] Example 1

[0070] The material components in Table 1 were weighed, in parts by mass, vinyl chloride monomer 1300g, deionized water 1956g, isodecyl acrylate ISODA 2.6g, ethoxylated trimethylolpropane triacrylate 2OEO 2.6g, four dispersants (KH-20 0.13g, L-9 0.52g, E50 0.26g, S202 0.26g), two initiators ((isopropyl peroxy neodecanoate CNP 0.52g, di(2-ethylhexyl) peroxydicarbonate EHP 0.13g). The test results are shown in Table 3.

[0071] Example 2

[0072] The material components in Table 1 were weighed, in parts by mass, including 1300 g of vinyl chloride monomer, 2615 g of deionized water, 5.2 g of isodecyl acrylate ISODA, 5.2 g of ethoxylated trimethylolpropane triacrylate 2OEO, four dispersants (0.26 g of KH-20, 0.78 g of L-9, 0.39 g of E50, and 0.39 g of S202), and two initiators (0.65 g of isopropyl peroxyneodecanoate CNP and 0.26 g of bis(2-ethylhexyl) peroxydicarbonate EHP). The test results are shown in Table 3.

[0073] Example 3

[0074] The material components in Table 1 were weighed, in parts by mass, vinyl chloride monomer 1300g, deionized water 2259g, isodecyl acrylate ISODA 3.9g, ethoxylated trimethylolpropane triacrylate 2OEO 3.9g, four dispersants (KH-20 0.2g, L-9 0.63g, E50 0.32g, S202 0.32g), two initiators ((isopropyl peroxy neodecanoate CNP 0.59g, di(2-ethylhexyl) peroxydicarbonate EHP 0.21g). The test results are shown in Table 3.

[0075] Example 4

[0076] The material components and preparation method provided in this embodiment are the same as those in Example 1, except that: based on 100 wt% of the vinyl chloride monomer, the mass of the isodecyl acrylate ISODA structural unit b is 2 g, which is not within the scope of the present invention. The test results are shown in Table 3.

[0077] Example 5

[0078] The material components and preparation method provided in this embodiment are the same as those in Example 1, except that: based on 100 wt% of the vinyl chloride monomer, the mass of the structural unit c provided by ethoxylated trimethylolpropane triacrylate is 2 g, which is not within the scope of the present invention. The test results are shown in Table 3.

[0079] Example 6

[0080] The material components and preparation method provided in this embodiment are the same as those in Example 1, in terms of mass fractions, vinyl chloride monomer 1300g, deionized water 3000g, isodecyl acrylate ISODA 2.6g, ethoxylated trimethylolpropane triacrylate 2OEO2.6g, four dispersants (KH-20 0.13g, L-9 0.52g, E500.26g, S202 0.26g), two initiators ((isopropyl peroxy neodecanoate CNP 0.52g, di(2-ethylhexyl) peroxydicarbonate EHP 0.13g). The test results are shown in Table 3.

[0081] Example 7

[0082] The material components and preparation method provided in this embodiment are the same as those in Example 1, in parts by mass, vinyl chloride monomer 1300g, deionized water 1956g, isodecyl acrylate ISODA 2.6g, ethoxylated trimethylolpropane triacrylate 2OEO2.6g, four dispersants (KH-20 0.13g, L-9 0.52g, E500.52g, S202 0.13g), two initiators ((isopropyl peroxy neodecanoate CNP 0.52g, di(2-ethylhexyl) peroxydicarbonate EHP 0.13g). The test results are shown in Table 3.

[0083] Example 8

[0084] The material components and preparation method provided in this embodiment are the same as those in Example 1, in terms of mass fractions, vinyl chloride monomer 1300g, deionized water 1956g, isodecyl acrylate ISODA 2.6g, ethoxylated trimethylolpropane triacrylate 2OEO2.6g, four dispersants (KH-20 0.13g, L-9 0.26g, E500.26g, S202 0.52g), two initiators ((isopropyl peroxy neodecanoate CNP 0.52g, di(2-ethylhexyl) peroxydicarbonate EHP 0.13g). The test results are shown in Table 3.

[0085] Comparative Example 1

[0086] The material components and preparation method provided in this comparative example are the same as those in Example 1, and the material components are weighed according to Table 2, except that the structural unit b is provided by tricyclodecane dimethanol diacrylate, with a mass of 3.9 g, and the structural unit c is provided by dicyclopentenyl acrylate, with a mass of 3.9 g. The test results are shown in Table 3.

[0087] Comparative Example 2

[0088] The material components and preparation method provided in this comparative example are the same as those in Example 1, and the material components are weighed according to Table 2, except that the structural unit b is provided by tricyclodecane dimethanol diacrylate, with a mass of 3.9 g, and no structural unit c is provided. The test results are shown in Table 3.

[0089] Comparative Example 3

[0090] The material components and preparation method provided in this comparative example are the same as those in Example 1, and the material components are weighed according to Table 2, except that the structural unit c is provided by dicyclopentenyl acrylate, with a mass of 3.9 g, and the structural unit b is not provided. The test results are shown in Table 3.

[0091] Table 1

[0092]

[0093] Table 2

[0094]

[0095]

[0096] Table 3

[0097]

[0098] It can be seen from the examples and comparative examples that isodecyl acrylate (ISODA) and ethoxylated trimethylolpropane triacrylate (2OEO) have the effect of synergistically improving the cold resistance and surface roughness of PVC resin. According to comparative data analysis, tricyclodecane dimethanol diacrylate and dicyclopentenyl acrylate are not as good as isodecyl acrylate (ISODA) and ethoxylated trimethylolpropane triacrylate (2OEO) in synergistic performance.

[0099] 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, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A PVC resin, It is characterized in that The resin comprises: a structural unit a provided by vinyl chloride, a structural unit b provided by isodecyl acrylate and a structural unit c provided by ethoxylated trimethylolpropane triacrylate.

2. The PVC resin according to claim 1, in, Based on 100 wt% of vinyl chloride monomer, The mass of the structural unit b is 0.2-0.4wt% of the mass of the vinyl chloride monomer; and / or The mass of the structural unit c is 0.2-0.4wt% of the mass of the vinyl chloride monomer; and / or The resin has a three-dimensional network structure.

3. A method for preparing the PVC resin according to claim 1 or 2, It is characterized in that The method includes: In the presence of an initiator, isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride are copolymerized; Preferably, the copolymerization method comprises: Deionized water, isodecyl acrylate, ethoxylated trimethylolpropane triacrylate, a dispersant, an initiator, and vinyl chloride are mixed for copolymerization, a terminator is added to terminate the reaction, solid-liquid separation is performed, and drying is performed; Further preferably, the method comprises: (a) mixing deionized water, isobutyl acrylate, ethoxylated trimethylolpropane triacrylate, a dispersant, and an initiator; (b) adding vinyl chloride to the mixed material to carry out copolymerization reaction; (c) After the copolymerization reaction, a terminator is added to terminate the reaction, and the solid-liquid separation and drying are performed.

4. The preparation method according to claim 3, in, The ratio of the mass of the deionized water to the total mass of isodecyl acrylate, ethoxylated trimethylolpropane triacrylate and vinyl chloride monomer is (1.4-2.1):1; and / or The amount of the dispersant used is 0.09-0.14wt% of the amount of vinyl chloride used; and / or The amount of the initiator used is 0.05-0.07 wt % of the amount of vinyl chloride used.

5. The preparation method according to claim 3 or 4, in, The dispersant comprises at least one of polyvinyl alcohol dispersants, cellulose ethers, fatty alcohol polyoxyethylene ethers, gelatin and alkylphenol polyoxyethylene ethers, preferably a mixture of polyvinyl alcohol dispersants and cellulose ethers, more preferably a mass ratio of polyvinyl alcohol dispersants to cellulose ethers of (0.91-1.43): (0.26-0.39); Preferably, The polyvinyl alcohol dispersant is selected from at least one of KH-20, L-9, S202, L-11, L-0 and 420, preferably a mixture of KH-20, L-9 and S202, and more preferably, the mass ratio of KH-20, L-9 and S202 in the mixture is (0.13-0.26): (0.52-0.78): (0.26-0.39); and / or The cellulose ether is selected from at least one of E50 and FON50; and / or The initiator is selected from at least one of azobisisoheptanenitrile, diisobutyryl peroxide, cumyl peroxyneodecanoate, bis(2-ethylhexyl) peroxydicarbonate and t-pentyl peroxyneodecanoate; Preferably, it is one or both of cumyl peroxyneodecanoate and bis(2-ethylhexyl)peroxydicarbonate; More preferably, it is a mixture of cumyl peroxyneodecanoate and bis(2-ethylhexyl)peroxydicarbonate; More preferably, the mass ratio of cumyl peroxyneodecanoate to bis(2-ethylhexyl) peroxydicarbonate in the mixture is (0.52-0.65):(0.13-0.26).

6. The preparation method according to any one of claims 3 to 5, in, The mixing conditions in step (a) include: Temperature of 15-25°C; and / or The time is 10-30 minutes; and / or The copolymerization conditions include: Temperature of 51-53°C; and / or The pressure is 0.860-0.875MPa; and / or The time is 300-490 minutes.

7. Use of the PVC resin according to claim 1 or 2 in film preparation.

8. A PVC film raw material composition, It is characterized in that The raw material composition comprises the PVC resin according to claim 1 or 2; Preferably, the raw material composition contains: PVC resin, stabilizer, plasticizer and lubricant; Preferably, the mass ratio of the PVC resin, stabilizer, plasticizer and lubricant is 100: (5.0-7.0)∶(30-50)∶(5-10)∶(0.2-0.4)； More preferably, The plasticizer is DOP plasticizer and / or DOS plasticizer.

9. A method for preparing a PVC film, It is characterized in that The method comprises: molding a PVC film raw material composition, wherein the PVC film raw material composition comprises the composition according to claim 8.

10. The PVC film prepared by the method for preparing a PVC film according to claim 9, preferably, The film has a brittle temperature of 35-40°C; and / or The thickness of the film is 0.7-1 μm.

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