A tensile PVC film and its preparation method

Abstract

This application relates to a tensile PVC film and its preparation method, comprising the following raw materials in parts by weight: 100-140 parts by weight of PVC resin, 35-55 parts by weight of dioctyl terephthalate, 3-8 parts by weight of dioctyl adipate, 3-6 parts by weight of zinc-calcium composite stabilizer, 4-6 parts by weight of β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil, 15-25 parts by weight of hydrogenated ricinoleic acid modified nano-calcium carbonate, 8-12 parts by weight of heavy calcium carbonate, 3-5 parts by weight of titanium dioxide, and 0.01-0.03 parts by weight of colorant. This PVC film exhibits good tensile strength and elongation at break, with a longitudinal tensile strength >28.5 MPa, a transverse tensile strength >24 MPa, a longitudinal elongation at break >285%, and a transverse elongation at break >315%.

Description

Technical Field

[0001] This application relates to the field of polymer technology, and in particular to a tensile PVC film and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) film is widely used in packaging, building materials, electronics, automotive and other fields due to its excellent transparency, weather resistance, barrier properties and cost-effectiveness. Especially in the field of metal sheet surface protection, PVC protective film needs to withstand the mechanical stretching during processing and the deformation when laminating complex curved surfaces, which places stringent requirements on the balance of mechanical properties.

[0003] However, PVC itself has drawbacks such as high brittleness, poor impact resistance, and susceptibility to cracking at low temperatures. Traditional PVC films typically improve flexibility by adding phthalate plasticizers (such as DOP and DOTP), but this often comes at the cost of tensile strength. As the amount of plasticizer increases, the tensile strength of the PVC film decreases significantly, and the plasticizer is prone to migration and precipitation, leading to unstable film performance.

[0004] Therefore, overcoming the bottleneck of the difficulty in achieving both strength and toughness in PVC materials and developing high-performance PVC films with both high tensile strength and high elongation at break has become a key technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] This invention provides a tensile PVC film and its preparation method, which can improve the ability of PVC film to resist deformation and breakage when subjected to external tensile force.

[0006] In a first aspect of this application, a tensile PVC film is provided, comprising the following raw materials in parts by weight: 100-140 parts by weight of PVC resin, 35-55 parts by weight of dioctyl terephthalate, 3-8 parts by weight of dioctyl adipate, 3-6 parts by weight of zinc-calcium composite stabilizer, 4-6 parts by weight of β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil, 15-25 parts by weight of hydrogenated ricinoleic acid modified nano-calcium carbonate, 8-12 parts by weight of heavy calcium carbonate, 3-5 parts by weight of titanium dioxide, and 0.01-0.03 parts by weight of colorant; the raw materials for preparing the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil include HEA, MHHPA, and epoxidized soybean oil.

[0007] By adopting the above technical solution, this application provides a tensile-resistant PVC film with good tensile strength and elongation at break, exhibiting a longitudinal tensile strength >28.5 MPa, a transverse tensile strength >24 MPa, a longitudinal elongation at break >285%, and a transverse elongation at break >315%. This is likely because the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil acts as a connector between the PVC matrix and the hydrogenated ricinoleic acid modified nano-calcium carbonate, allowing stress to be effectively transferred from the PVC matrix to the nano-calcium carbonate particles. Furthermore, the hydrogenated ricinoleic acid modified nano-calcium carbonate is uniformly dispersed in the PVC, preventing crack propagation when the material is under stress. Moreover, the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and the hydrogenated ricinoleic acid modified nano-calcium carbonate work synergistically to enhance the tensile strength and elongation at break of the PVC film.

[0008] Optionally, the weight ratio of the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and the hydrogenated ricinoleic acid modified nano-calcium carbonate is 10.5:(27-77).

[0009] By adopting the above technical solution and adjusting the amounts of β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and hydrogenated ricinoleic acid modified nano-calcium carbonate according to the above weight ratio, when the weight ratio of β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and hydrogenated ricinoleic acid modified nano-calcium carbonate is 10.5:(27-77), it can be ensured that the prepared PVC film has good tensile strength and elongation at break.

[0010] Optionally, the preparation method of the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil includes the following steps: a1. Mix HEA and MHHPA, then add p-methoxyphenol and triphenylphosphine, and heat to 100-120℃ to obtain a mixture; a2. Add epoxidized soybean oil to step a1, then add p-methoxyphenol and triphenylphosphine, and react to obtain β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil.

[0011] Optionally, in step a1, the molar ratio of HEA to MHHPA is (1.05-1.1):1.

[0012] By adopting the above technical solution and adjusting the amounts of HEA and MHHPA according to the above molar ratio, when the molar ratio of HEA to MHHPA is (1.05-1.1):1, the prepared PVC film can be guaranteed to have good tensile strength and elongation at break. This may be because, on the one hand, when the molar ratio of HEA to MHHPA is controlled within the range of (1.05-1.1):1, it ensures that MHHPA reacts fully and that the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil retains an appropriate amount of residual hydroxyl groups and acrylate double bonds. These groups form hydrogen bonds with PVC and chemical bridging interfaces with hydrogenated ricinoleic acid modified nano-calcium carbonate, achieving effective stress transfer. On the other hand, at this molar ratio, the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil has both the supporting role of rigid hexahydrophthalic anhydride rings and the deformability of flexible soybean oil segments, thereby improving the tensile strength and elongation at break of the PVC film.

[0013] Optionally, in step a1, p-methoxyphenol accounts for 0.1-0.2% of the total mass of HEA and MHHPA, and triphenylphosphine accounts for 1.2-1.6% of the total mass of HEA and MHHPA.

[0014] Optionally, in step a2, p-methoxyphenol accounts for 0.1-0.2% of the mass of epoxidized soybean oil, and triphenylphosphine accounts for 1.2-1.6% of the mass of epoxidized soybean oil.

[0015] Optionally, the preparation method of the hydrogenated ricinoleic acid modified nano-calcium carbonate includes the following steps: Nano-calcium carbonate and hydrogenated ricinoleic acid are mixed at 60-80℃ for 10-20 min to obtain hydrogenated ricinoleic acid modified nano-calcium carbonate.

[0016] In a second aspect of this application, a method for preparing the tensile PVC film described in the first aspect is provided, comprising the following steps: S1. Mix β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and hydrogenated ricinoleic acid modified nano-calcium carbonate to obtain a premix. S2. Mix PVC resin, dioctyl terephthalate, dioctyl adipate, zinc-calcium composite stabilizer, the premix obtained in step S1, heavy calcium carbonate, titanium dioxide, and colorant, discharge and cool to obtain dry mix. S3. The dry mixture obtained in step S2 is kneaded, plasticized, filtered, calendered, stretched, cooled, and slit to obtain a tensile PVC film.

[0017] Optionally, in step S1, the mixing conditions are stirring at 80-90°C for 20-30 minutes.

[0018] In a third aspect of this application, the application of the tensile PVC film described in the first aspect on the surface of a metal plate is provided.

[0019] In summary, the present invention has at least one of the following beneficial technical effects: 1. This application provides a tensile-strength PVC film with good tensile strength and elongation at break, exhibiting a longitudinal tensile strength >28.5 MPa, a transverse tensile strength >24 MPa, a longitudinal elongation at break >285%, and a transverse elongation at break >315%. Acrylic acid-β-hydroxyethyl ester / methylhexahydrophthalic anhydride modified epoxidized soybean oil acts as a connector between the PVC matrix and hydrogenated ricinoleic acid modified nano-calcium carbonate, enabling effective stress transfer from the PVC matrix to the nano-calcium carbonate particles. The hydrogenated ricinoleic acid modified nano-calcium carbonate is uniformly dispersed in the PVC, preventing crack propagation under stress. Furthermore, the synergistic effect of acrylic acid-β-hydroxyethyl ester / methylhexahydrophthalic anhydride modified epoxidized soybean oil and hydrogenated ricinoleic acid modified nano-calcium carbonate enhances the tensile strength and elongation at break of the PVC film.

[0020] 2. This application provides an application of tensile PVC film on the surface of a metal plate. The longitudinal tensile strength of the PVC film is >28.5MPa, which can withstand mechanical traction during processing. The transverse elongation at break is >315%, which can adapt to the bonding deformation of complex curved surfaces. It maintains complete coverage during the deep processing of metal plates such as stamping, bending, and edge rolling, without tearing or becoming brittle, thus solving the processing failure problem caused by the imbalance of strength and toughness of traditional plasticized PVC films. Detailed Implementation

[0021] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] Epoxidized soybean oil (ESO) was purchased from Guangzhou Haierma Vegetable Oil Co., Ltd. (acid value 0.6 mg KOH / g, epoxy value 0.65%), β-hydroxyethyl acrylate (HEA) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., nano calcium carbonate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. (C886288), heavy calcium carbonate was purchased from Jinan Shengfeng Industry and Trade Co., Ltd. (1250 mesh), hydrogenated ricinoleic acid (12-hydroxystearic acid) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (H14927), PVC resin was purchased from Xinjiang Zhongtai Chemical Co., Ltd. (SG-5), calcium-zinc composite stabilizer was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd. (PA95478), and ultramarine was purchased from Shenyang Elepx Chemical Co., Ltd.

[0023] Preparation Example 1 Preparation of β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil a1. Mix HEA and MHHPA in a molar ratio of 1.08:1, then add 0.15% p-methoxyphenol (MEHQ) and 1.4% triphenylphosphine (TPP) by mass of HEA and MHHPA, and slowly heat to 110°C to obtain a mixture. a2. After the acid value of the reaction system in step a1 stabilizes, epoxidized soybean oil is added. The amount of epoxidized soybean oil added is calculated based on the molar ratio of epoxy groups to carboxyl groups after conversion of the actual acid value at a ratio of 1.1:1. Then, p-methoxyphenol and triphenylphosphine are added, wherein p-methoxyphenol and triphenylphosphine account for 0.15% and 1.4% of the mass of epoxidized soybean oil, respectively. The temperature is controlled at 100℃. During the reaction, samples are continuously taken to test the acid value. When the acid value drops to 5 mg / g, the reaction is stopped to obtain β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil (HEAMHHPA-ESO).

[0024] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is that in step a1, the molar ratio of HEA and MHHPA is 1.05:1.

[0025] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in step a1, the molar ratio of HEA and MHHPA is 1.1:1.

[0026] Preparation Example 4 Preparation of hydrogenated ricinoleic acid-modified nano-calcium carbonate Nano-calcium carbonate and hydrogenated ricinoleic acid were added to a planetary kneader in a metered manner and mixed. The amount of hydrogenated ricinoleic acid added was 3.5% of the mass of nano-calcium carbonate, resulting in hydrogenated ricinoleic acid-modified nano-calcium carbonate. The central kneading speed of the planetary kneader was 15 r / min, the eccentric kneading speed was 40 r / min, the temperature was 70℃, and the kneading time was 15 min. The hydrogenated ricinoleic acid was preheated to 70℃ and then atomized and sprayed in.

[0027] Comparative Preparation Example 1 The difference between Preparation Example 1 and Preparation Example 2 is that in step a1, HEA is replaced with pentaerythritol triacrylate (PETA) in equimolar amounts.

[0028] Specifically, step a1 is different, and is as follows: a1: PETA and MHHPA are mixed in a molar ratio of 1.08:1, and then 0.15% of p-methoxyphenol (MEHQ) and 1.4% of triphenylphosphine (TPP) of the total mass of PETA and MHHPA are added. The mixture is then slowly heated to 110°C to obtain a mixture.

[0029] Accordingly, step a2 is as follows: after the acid value of the reaction system in step a1 stabilizes, epoxidized soybean oil is added. The amount of epoxidized soybean oil added is calculated according to the ratio of the number of moles of epoxy groups to the number of moles of carboxyl groups after conversion of the actual acid value at 1.1:1. Then, p-methoxyphenol and triphenylphosphine are added, wherein p-methoxyphenol and triphenylphosphine account for 0.15% and 1.4% of the mass of epoxidized soybean oil, respectively. The temperature is controlled at 100℃. During the reaction, the acid value is continuously sampled and tested. When the acid value drops to 5 mg / g, the reaction is stopped to obtain pentaerythritol triacrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil (PETAMHHPA-ESO).

[0030] Example 1

[0031] Example 1 provides a tensile PVC film comprising the following raw materials in parts by weight: 120 parts by weight of PVC resin, 45 parts by weight of dioctyl terephthalate, 5.5 parts by weight of dioctyl adipate, 4.5 parts by weight of zinc-calcium composite stabilizer, 5 parts by weight of HEAMHHPA-ESO prepared by the preparation method of Example 1, 20 parts by weight of hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Example 4, 10 parts by weight of heavy calcium carbonate, 4 parts by weight of titanium dioxide, and 0.02 parts by weight of colorant; wherein the colorant is ultramarine blue.

[0032] Preparation method S1. The HEAMHHPA-ESO prepared by the preparation method of Preparation Example 1 and the hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Preparation Example 4 were added to a high-speed mixer and stirred at 85°C and 1000 rpm for 25 min to obtain a premix. S2. Add PVC resin, dioctyl terephthalate, dioctyl adipate, zinc-calcium composite stabilizer, premix obtained in step S1, heavy calcium carbonate, titanium dioxide, and ultramarine to a high-speed mixer. Stir at 1000 rpm for 2 minutes, then stir at 2200 rpm until the temperature reaches 105°C. Discharge and cool to obtain dry mix. S3. Add the dry mixture obtained in step S2 to the internal mixer and internally mix and plasticize at 170°C for 5 minutes. Then, plasticize it evenly by passing it through a two-roll mill (front roll 170°C, rear roll 180°C). Filter it through a double layer of 80-mesh and 120-mesh stainless steel wire mesh, and calender it at 185°C. After longitudinal stretching (stretch ratio of 1.3, stretching temperature of 190°C, stretching rate of 15m / min), cooling, and slitting, a tensile PVC film with a thickness of 0.2mm is obtained.

[0033] Example 2

[0034] Example 2 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the total weight of HEAMHHPA-ESO prepared by the preparation method of Example 1 and hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Example 4 remains unchanged, and the weight ratio of HEAMHHPA-ESO to hydrogenated ricinoleic acid modified nano-calcium carbonate is 3:22.

[0035] Other preparation methods are the same as in Example 1.

[0036] Example 3

[0037] Example 3 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the total weight of HEAMHHPA-ESO prepared by the preparation method of Example 1 and hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Example 4 remains unchanged, and the weight ratio of HEAMHHPA-ESO to hydrogenated ricinoleic acid modified nano-calcium carbonate is 7:18.

[0038] Other preparation methods are the same as in Example 1.

[0039] Example 4

[0040] Example 4 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the HEAMHHPA-ESO prepared by the preparation method of Example 1 is replaced by an equal weight of HEAMHHPA-ESO prepared by the preparation method of Example 2.

[0041] Other preparation methods are the same as in Example 1.

[0042] Example 5

[0043] Example 5 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the HEAMHHPA-ESO prepared by the preparation method of Example 1 is replaced by an equal weight of HEAMHHPA-ESO prepared by the preparation method of Example 3.

[0044] Other preparation methods are the same as in Example 1.

[0045] Comparative Example 1 Comparative Example 1 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the HEAMHHPA-ESO prepared by the preparation method of Example 1 is replaced by an equal weight of hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Example 4.

[0046] Other preparation methods are the same as in Example 1.

[0047] Comparative Example 2 Comparative Example 2 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the hydrogenated castor oil acid modified nano calcium carbonate prepared by the preparation method of Preparation Example 4 is replaced by an equal weight of HEAMHHPA-ESO prepared by the preparation method of Preparation Example 1.

[0048] Other preparation methods are the same as in Example 1.

[0049] Comparative Example 3 Comparative Example 3 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the HEAMHHPA-ESO prepared by the preparation method of Example 1 is replaced by an equal weight of PETAMHHPA-ESO prepared by the preparation method of Comparative Example 1.

[0050] Other preparation methods are the same as in Example 1.

[0051] Comparative Example 4 Comparative Example 4 provides a tensile PVC film, which differs from Example 1 in that, in step S1, the hydrogenated ricinoleic acid modified nano-calcium carbonate prepared by the preparation method of Example 4 is replaced by an equal weight of nano-calcium carbonate.

[0052] Other preparation methods are the same as in Example 1.

[0053] Performance testing The tensile PVC films prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to tensile strength and elongation at break tests. The tensile strength and elongation at break were tested using an electronic tensile testing machine according to GB / T1040.3-2006. Three parallel experiments were set up for each group of tests, and the average value was taken. The results are shown in Table 1.

[0054] Table 1

[0055] Conclusion Analysis and Summary As shown in Examples 1-3 and Table 1, adjusting the weight ratio of HEAMHHPA-ESO and hydrogenated ricinoleic acid-modified nano-calcium carbonate can affect the tensile strength and elongation at break of the PVC film. In Example 1, the PVC film prepared with a weight ratio of 1:4 of HEAMHHPA-ESO and hydrogenated ricinoleic acid-modified nano-calcium carbonate exhibits the best tensile strength and elongation at break, superior to that of Examples 2 and 3.

[0056] As can be seen from Examples 1, 4-5, and Table 1, adjusting the molar ratio of HEA and MHHPA in HEAMHHPA-ESO can affect the tensile strength and elongation at break of the PVC film. In Example 1, the PVC film prepared with a molar ratio of HEA to MHHPA of 1.08:1 exhibits the best tensile strength and elongation at break performance, superior to that of Examples 4 and 5.

[0057] Based on Examples 1, Comparative Examples 1-2, and Table 1, it can be seen that replacing an equal weight of HEAMHHPA-ESO with hydrogenated ricinoleic acid-modified nano-calcium carbonate in Comparative Example 1 and replacing an equal weight of hydrogenated ricinoleic acid-modified nano-calcium carbonate with HEAMHHPA-ESO in Comparative Example 2 significantly worsened the tensile strength and elongation at break of the prepared PVC films. This may be because HEAMHHPA-ESO acts as a connector between the PVC matrix and the hydrogenated ricinoleic acid-modified nano-calcium carbonate, allowing stress to be effectively transferred from the PVC matrix to the nano-calcium carbonate particles. Meanwhile, the hydrogenated ricinoleic acid-modified nano-calcium carbonate is uniformly dispersed in the PVC, preventing crack propagation when the material is under stress. Furthermore, HEAMHHPA-ESO and hydrogenated ricinoleic acid-modified nano-calcium carbonate work synergistically to enhance the tensile strength and elongation at break of the PVC film. Therefore, the absence of either component leads to a significant deterioration in the tensile strength and elongation at break of the PVC film.

[0058] Based on Examples 1, Comparative Example 3, and Table 1, it can be seen that in Comparative Example 3, replacing HEAMHHPA-ESO with an equal weight of PETAMHHPA-ESO significantly worsened the tensile strength and elongation at break of the prepared PVC film. This may be because PETAMHHPA-ESO was prepared by replacing HEA with pentaerythritol triacrylate (PETA). The trifunctional structure of PETA leads to highly branched products. Although it retains the hydroxyl groups that react with MHHPA and the carboxyl groups that react with ESO, the number of residual double bonds is three times that of HEAMHHPA-ESO. These double bonds are prone to thermal polymerization at processing temperatures, forming localized gel networks. Consequently, on the one hand, the interfacial layer with hydrogenated ricinoleic acid-modified nano-calcium carbonate becomes too rigid due to the cross-linking of multiple functional groups, resulting in decreased stress transfer efficiency and a significant decrease in tensile strength; on the other hand, it restricts the slippage and orientation of PVC molecular chains, significantly reducing the elongation at break.

[0059] Based on Example 1, Comparative Example 4, and Table 1, it can be seen that in Comparative Example 4, replacing an equal weight of hydrogenated ricinoleic acid-modified nano-calcium carbonate with nano-calcium carbonate significantly reduced the tensile strength and elongation at break of the prepared PVC film. This may be because unmodified nano-calcium carbonate has high surface energy and strong hydrophilicity, resulting in poor compatibility with PVC. It is prone to agglomeration during processing, and these agglomerates become stress concentration points in the material, easily leading to material fracture under external forces.

[0060] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the products, methods and principles of this application should be covered within the scope of protection of this application.

Claims

1. A tensile-resistant PVC film, characterized in that, The raw materials include the following parts by weight: 100-140 parts by weight of PVC resin, 35-55 parts by weight of dioctyl terephthalate, 3-8 parts by weight of dioctyl adipate, 3-6 parts by weight of zinc-calcium composite stabilizer, 4-6 parts by weight of β-hydroxyethyl acrylate / methyl hexahydrophthalic anhydride modified epoxidized soybean oil, 15-25 parts by weight of hydrogenated ricinoleic acid modified nano-calcium carbonate, 8-12 parts by weight of heavy calcium carbonate, 3-5 parts by weight of titanium dioxide, and 0.01-0.03 parts by weight of colorant; The raw materials for preparing the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil include HEA, MHHPA, and epoxidized soybean oil.

2. The tensile PVC film according to claim 1, characterized in that, The weight ratio of the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and the hydrogenated castor oil acid modified nano-calcium carbonate is 10.5:(27-77).

3. The tensile PVC film according to claim 1, characterized in that, The preparation method of the β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil includes the following steps: a1. Mix HEA and MHHPA, then add p-methoxyphenol and triphenylphosphine, and heat to 100-120℃ to obtain a mixture; a2. Add epoxidized soybean oil to step a1, then add p-methoxyphenol and triphenylphosphine, and react to obtain β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil.

4. The tensile-resistant PVC film according to claim 3, characterized in that, In step a1, the molar ratio of HEA to MHHPA is (1.05-1.1):

1.

5. The tensile PVC film according to claim 3, characterized in that, In step a1, p-methoxyphenol accounts for 0.1-0.2% of the total mass of HEA and MHHPA, and triphenylphosphine accounts for 1.2-1.6% of the total mass of HEA and MHHPA.

6. The tensile PVC film according to claim 3, characterized in that, In step a2, p-methoxyphenol accounts for 0.1-0.2% of the mass of epoxidized soybean oil, and triphenylphosphine accounts for 1.2-1.6% of the mass of epoxidized soybean oil.

7. The tensile PVC film according to claim 1, characterized in that, The preparation method of the hydrogenated ricinoleic acid modified nano-calcium carbonate includes the following steps: Nano-calcium carbonate and hydrogenated ricinoleic acid are mixed at 60-80℃ for 10-20 min to obtain hydrogenated ricinoleic acid modified nano-calcium carbonate.

8. A method for preparing a tensile PVC film according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix β-hydroxyethyl acrylate / methylhexahydrophthalic anhydride modified epoxidized soybean oil and hydrogenated ricinoleic acid modified nano-calcium carbonate to obtain a premix. S2. Mix PVC resin, dioctyl terephthalate, dioctyl adipate, zinc-calcium composite stabilizer, the premix obtained in step S1, heavy calcium carbonate, titanium dioxide, and colorant, discharge and cool to obtain dry mix. S3. The dry mixture obtained in step S2 is kneaded, plasticized, filtered, calendered, stretched, cooled, and slit to obtain a tensile PVC film.

9. The method for preparing the tensile PVC film according to claim 8, characterized in that, In step S1, the mixing conditions are stirring at 80-90℃ for 20-30 minutes.

10. The application of the tensile PVC film according to any one of claims 1-7 on the surface of a metal plate.

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