A modified PPS biaxially oriented film and its preparation method

Abstract

The present application discloses a modified PPS biaxially oriented film and a preparation method thereof, relating to the field of films. The modified PPS biaxially oriented film comprises a core layer and outer layers provided on the upper and lower surfaces of the core layer, wherein the core layer is made of PPS resin, and the outer layers are made of modified PPS resin; wherein the modified PPS resin comprises the following raw material components: 80-85 parts by weight of PPS resin, 12-18 parts by weight of a toughening agent, 1-2 parts by weight of an antioxidant, and 1-2 parts by weight of an anti-sticking agent, wherein the toughening agent comprises at least one of a PPO resin and a HIPS resin. The modified PPS biaxially oriented film of the present application has both toughness and low dielectric properties, good film-forming properties, and can be applied to the field of electrical insulation.

Description

Technical Field

[0001] The present application relates to the field of films, and in particular to a modified PPS biaxially oriented film and a preparation method thereof. Background Art

[0002] Polyphenylene sulfide (PPS) is a high-performance engineering plastic widely used in the electronics, automotive, aerospace, and other fields due to its excellent heat resistance, chemical resistance, and mechanical properties. However, conventional PPS resins are limited in their application in thin films due to the high rigidity of the benzene ring, brittleness, poor stretchability, and poor film-forming properties.

[0003] At present, related technologies use thermoplastic polyurethane, maleic anhydride grafted acrylonitrile-butadiene-styrene copolymer, etc. to toughen and modify PPS resin to improve the film-forming properties of PPS resin. However, while thermoplastic polyurethane and maleic anhydride grafted styrene-ethylene-butadiene-styrene block copolymer improve the film-forming properties of PPS resin, they are likely to sacrifice the dielectric properties of PPS resin, affecting the application of PPS film in the field of electrical insulation. Summary of the Invention

[0004] In order to improve the problem in the related art that it is difficult to achieve both flexibility and low dielectric properties in PPS films, the present application provides a modified PPS biaxially oriented film and a preparation method thereof.

[0005] In the first aspect, the present application provides a modified PPS biaxially oriented film adopting the following technical solution:

[0006] A modified PPS biaxially oriented film comprises a core layer and outer layers arranged on the upper and lower surfaces of the core layer, wherein the core layer is made of PPS resin, and the outer layers are made of modified PPS resin; wherein the modified PPS resin comprises the following raw material components: 80-85 parts by weight of PPS resin, 12-18 parts by weight of a toughening agent, 1-2 parts by weight of an antioxidant, and 1-2 parts by weight of an anti-sticking agent, wherein the toughening agent comprises at least one of a PPO resin and a HIPS resin.

[0007] In the present application, the modified PPS biaxially oriented film comprises a core layer and two outer layers arranged on the upper and lower surfaces of the core layer, the core layer adopts common PPS resin, the outer layer adopts toughened modified modified PPS resin, and the toughening agent adopted by the modified PPS resin is at least one of PPO resin and HIPS resin. Wherein, PPO resin can toughen PPS resin by improving the modulus and strength of the blend, and HIPS resin can absorb energy during plastic deformation by the internal rubber phase to achieve the purpose of toughening PPS resin. Moreover, when adopting general PPO resin and HIPS resin to toughen PPS resin, owing to having good interface compatibility between PPO resin, HIPS resin and PPS resin, in the biaxial stretching process, the dielectric properties of the modified PPS biaxially oriented film will not be reduced, which is conducive to obtaining a modified PPS biaxially oriented film with both toughness and low dielectric properties.

[0008] In addition, compared with using only modified PPS resin to prepare modified PPS biaxially oriented film, using ordinary PPS resin to prepare the core layer and modified PPS resin to prepare the outer layer can not only obtain a film with good film-forming properties, but also help reduce the cost of the film.

[0009] In some specific embodiments of the present application, the thickness ratio of the core layer to the outer layer is 3:(1-1.5).

[0010] In the present application, the thickness ratio of the core layer to the outer layer is controlled at 3:(1-1.5), which is beneficial for obtaining a modified PPS biaxially oriented film with good toughness, enabling the modified PPS biaxially oriented film to be smoothly formed during the production process, and is also beneficial for taking into account the cost of the modified PPS biaxially oriented film.

[0011] In some specific embodiments of the present application, the toughening agent is a composition of PPO resin and HIPS resin, and the weight ratio of the PPO resin to the HIPS resin is 1:(3-4).

[0012] In the present application, the toughening agent adopts a composition of PPO resin and HIPS resin in a weight ratio of 1: (3-4), wherein the PPO resin can toughen the PPS resin by increasing the modulus and strength of the blend, and the HIPS resin can absorb energy through plastic deformation. The two act synergistically to improve the overall toughness of the modified PPS resin. In addition, since the PPO resin has high heat resistance, the heat resistance of the modified PPS resin can be further improved, thereby obtaining a modified PPS resin with both flexibility and excellent heat resistance, which has a further promoting effect on improving the thermal stability of the modified PPS biaxially oriented film.

[0013] In some specific embodiments of the present application, the preparation method of the HIPS resin comprises the following steps:

[0014] 85-92 parts by weight of styrene, 5.5-6.2 parts by weight of toughening rubber, 1.8-2.6 parts by weight of the phase

[0015] The solvent is uniformly dispersed in 35-50 parts by weight of a solvent, and then 1-2 parts by weight of an initiator is dropwise added. The reaction is first carried out at 100-110° C. with stirring for 0.5-0.8 hours at a stirring speed of 5-10 r / min under a pressure of 0.3-0.4 MPa; then the reaction is carried out at 120-140° C. with stirring for 1.5-2 hours at a stirring speed of 30-35 r / min; and then the reaction is carried out at 155-165° C. with stirring for 1.5-2 hours at a stirring speed of 5-10 r / min. Finally, the unreacted styrene and solvent are recovered, and the material is granulated to obtain a HIPS resin.

[0016] In the present application, styrene, toughening rubber and compatibilizer are uniformly dispersed in the solvent in advance, which helps to form a uniform blending system during the polymerization process. By carrying out staged reactions at different temperatures, the polymerization process can be optimized, which is conducive to obtaining a HIPS resin with little effect on the melt viscosity of the PPS resin and good dispersibility and compatibility in the PPS resin.

[0017] In some specific embodiments of the present application, the toughening rubber includes styrene-butadiene diblock copolymer and α,ω-dihydroxy polysiloxane, and the weight ratio of the styrene-butadiene diblock copolymer to the α,ω-dihydroxy polysiloxane is 1:(1-1.5).

[0018] In the present application, compared with using styrene-butadiene diblock copolymer alone as the toughening rubber of HIPS resin, when the toughening rubber uses a composition of a copolymer of styrene-butadiene diblock copolymer and α,ω-dihydroxy polysiloxane in a weight ratio of 1:(1-1.5), the HIPS resin can improve the flexibility of the modified PPS biaxially oriented film while further improving the heat resistance of the film.

[0019] In some specific embodiments of the present application, the viscosity of the α,ω-dihydroxy polysiloxane is 550-650 cs.

[0020] In some specific embodiments of the present application, the number average molecular weight of the styrene-butadiene diblock copolymer is 130,000-160,000, and the polydispersity index is 1.0-1.05.

[0021] In some specific embodiments of the present application, in the styrene-butadiene diblock copolymer, the mass fraction of styrene is 40-45%, and the mass fraction of butadiene is 55-60%.

[0022] In some specific embodiments of the present application, the compatibilizer is styrene-glycidyl methacrylate copolymer, and the mass fraction of epoxy groups in the styrene-glycidyl methacrylate copolymer is 3-6%.

[0023] In this application, the compatibilizer uses styrene-glycidyl methacrylate copolymer, and the mass fraction of the epoxy group is controlled to 3-6%, which is beneficial to improving the compatibility of α, ω-dihydroxy polysiloxane and polystyrene, and has an enhancing effect on further improving the flexibility of the HIPS resin to the modified PPS biaxially oriented film. In addition, it is also beneficial to further improve the heat resistance of the modified PPS biaxially oriented film.

[0024] In some specific embodiments of the present application, the initiator is at least one of diisopropylbenzene hydroperoxide, isopropylbenzene hydroperoxide, and tert-butyl hydroperoxide.

[0025] In the process of preparing HIPS resin, the initiator is at least one of diisopropylbenzene hydroperoxide, isopropylbenzene hydroperoxide and tert-butyl hydroperoxide, which has the advantages of high initiation efficiency and is conducive to reducing the residual monomer styrene.

[0026] In some specific embodiments of the present application, the antioxidant is a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of the antioxidant 1010 to the antioxidant 168 is 3:(1-2).

[0027] Antioxidant 1010 and antioxidant 168 have a synergistic effect and can effectively improve the stability of the polymer during the processing. In addition, they can also effectively delay the aging process of the film and extend the service life of the film.

[0028] In some specific embodiments of the present application, the anti-sticking agent is a silica masterbatch.

[0029] Silica masterbatch can create micro-roughness on the surface of modified PPS biaxially oriented films, reducing the contact area between films and providing an anti-sticking effect. Furthermore, compared to other organic anti-sticking agents, silica masterbatch does not affect the transparency and optical properties of the film. Furthermore, it does not migrate and can remain stable within the film.

[0030] In a second aspect, the present application provides a method for preparing a modified PPS biaxially oriented film using the following technical solution:

[0031] A method for preparing a modified PPS biaxially oriented film comprises the following steps:

[0032] PPS resin, toughening agent, antioxidant and anti-sticking agent are mixed and melt-extruded into granules to obtain

[0033] To modified PPS resin; the melting temperature is controlled at 295-305℃;

[0034] The modified PPS resin is fed into extruder A, and the PPS resin is fed into extruder B. The modified PPS resin in extruder A is melted and evenly distributed to the upper and lower flow channels of the die distributor. The PPS resin in extruder B is melted and distributed to the middle flow channel of the die distributor, and then cast to obtain a sheet.

[0035] The sheet is biaxially stretched to obtain a modified PPS biaxially stretched film.

[0036] In the present application, the modified PPS biaxially oriented film is prepared by the above method, which can improve the film-forming properties of the modified PPS biaxially oriented film while reducing the cost as much as possible.

[0037] In summary, this application has at least the following beneficial technical effects:

[0038] (1) In the present application, the modified PPS biaxially oriented film comprises a core layer and two outer layers arranged on the upper and lower surfaces of the core layer, wherein the core layer is made of ordinary PPS resin, and the outer layers are made of toughened modified PPS resin, and the toughening agent used in the modified PPS resin is at least one of PPO resin and HIPS resin. Among them, PPO resin can toughen PPS resin by increasing the modulus and strength of the blend, and HIPS resin can achieve the purpose of toughening PPS resin by absorbing energy during plastic deformation through the internal rubber phase. Moreover, when using general PPO resin and HIPS resin to toughen PPS resin, due to the good interface compatibility between PPO resin, HIPS resin and PPS resin, the dielectric properties of the modified PPS biaxially oriented film will not be reduced during the biaxial stretching process, which is conducive to obtaining a modified PPS biaxially oriented film with both toughness and low dielectric properties.

[0039] (2) In the present application, compared with using styrene-butadiene diblock copolymer alone as the toughening rubber of HIPS resin, when the toughening rubber uses a composition of a copolymer of styrene-butadiene diblock copolymer and α,ω-dihydroxypolysiloxane in a weight ratio of 1:(1-1.5), the HIPS resin can improve the flexibility of the modified PPS biaxially oriented film while further improving the heat resistance of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of a modified PPS biaxially oriented film according to an embodiment of the present application.

[0041] Description of reference numerals:

[0042] 1. Core layer; 2. Outer layer. DETAILED DESCRIPTION

[0043] The present application is further described below with reference to specific experiments. Unless otherwise specified, the raw materials of the present application can be obtained through commercial channels.

[0044] Preparation Example

[0045] [Preparation Example 1]

[0046] A HIPS resin is prepared by the following method:

[0047] 85 kg of styrene, 2.75 kg of styrene-butadiene diblock copolymer, 2.75 kg of α,ω-dihydroxy polysiloxane with a viscosity of 750 cs, and 1.8 kg of styrene-glycidyl methacrylate copolymer were uniformly dispersed in 35 kg of ethylbenzene. Then, 1 kg of initiator was dropwise added. Under a pressure of 0.3 MPa, the mixture was stirred at 100°C for 0.8 h at a stirring speed of 5 rpm, then at 120°C for 2 h at a stirring speed of 30 rpm, and then at 155°C for 2 h at a stirring speed of 10 rpm. Finally, the unreacted styrene and ethylbenzene were recovered, and the remaining polymer was pelletized to obtain HIPS resin. The styrene-butadiene diblock copolymer used in this preparation example had a number-average molecular weight of 136,000 and a polydispersity index of 1.04. The mass fraction of styrene and butadiene was 40% and 60% respectively. The mass fraction of epoxy groups in the styrene-glycidyl methacrylate copolymer was 3%.

[0048] [Preparation Example 2]

[0049] A HIPS resin is prepared by the following method:

[0050] 92 kg of styrene, 2.48 kg of styrene-butadiene diblock copolymer, 3.72 kg of α,ω-dihydroxy polysiloxane with a viscosity of 550 cs, and 2.6 kg of styrene-glycidyl methacrylate copolymer were uniformly dispersed in 50 kg of ethylbenzene, and then 2 kg of initiator was dropwise added. Under a pressure of 0.4 MPa, the mixture was stirred and reacted at 110°C for 0.5 h at a stirring speed of 10 r / min; then stirred and reacted at 140°C for 1.5 h at a stirring speed of 35 r / min; and then stirred and reacted at 165°C for 2 h at a stirring speed of 5 r / min. Finally, the unreacted styrene and ethylbenzene were recovered, and the remaining polymer was granulated to obtain HIPS resin. The styrene-butadiene diblock copolymer used in this preparation example has a number average molecular weight of 145,000, a polydispersity index of 1.01, a mass fraction of styrene of 45%, and a mass fraction of butadiene of 55%. In the styrene-glycidyl methacrylate copolymer, the mass fraction of epoxy groups is 6%.

[0051] [Preparation Example 3]

[0052] A HIPS resin, which differs from [Preparation Example 1] in that the amount of styrene-butadiene diblock copolymer used is 5 kg, and the amount of α,ω-dihydroxypolysiloxane used is 0.5 kg.

[0053] [Preparation Example 4]

[0054] A HIPS resin, which differs from [Preparation Example 1] in that the amount of styrene-butadiene diblock copolymer used is 1 kg, and the amount of α,ω-dihydroxypolysiloxane used is 4.5 kg.

[0055] Example

[0056] [Example 1]

[0057] A modified PPS biaxially oriented film, referring to Figure 1 , comprising a core layer 1 and an outer layer 2 arranged on the upper and lower surfaces of the core layer 1, wherein the thickness of the modified PPS biaxially oriented film is 25 μm, the thickness ratio of the core layer 1 to the outer layer 2 is 3:1, and the core layer 1 is made of PPS resin (Toray A900), and the outer layer 2 is made of modified PPS resin. The modified PPS resin includes the following raw material components: 80 kg PPS resin (Toray A900), 17 kg PPO resin (Saudi Basic Z2000), 0.6 kg antioxidant 1010, 0.4 kg antioxidant 168 and 2 kg silica masterbatch.

[0058] In this embodiment, the preparation method of the modified PPS biaxially oriented film includes the following steps:

[0059] PPS resin, PPO resin, antioxidant 1010, antioxidant 168 and silica masterbatch

[0060] After mixing the pellets, melt extrusion and pelletization were carried out at 305°C to obtain modified PPS resin;

[0061] The modified PPS resin was fed into extruder A, and the PPS resin was fed into extruder B. The modified PPS resin in extruder A was melted at 300°C and evenly distributed to the upper and lower flow channels of the die distributor. The PPS resin in extruder B was melted at 300°C and distributed to the middle flow channel of the die distributor. Then, a sheet with a thickness of 200 μm was cast.

[0062] The sheet was biaxially stretched, with the stretching ratio of longitudinal stretching and transverse stretching both being 3 times, to obtain

[0063] Modified PPS biaxially oriented film.

[0064] [Example 2]

[0065] A modified PPS biaxially oriented film, referring to Figure 1 , comprising a core layer 1 and an outer layer 2 arranged on the upper and lower surfaces of the core layer 1, wherein the thickness of the modified PPS biaxially oriented film is 25 μm, the thickness ratio of the core layer 1 to the outer layer 2 is 3:1, and the core layer 1 is made of PPS resin (Toray A900), and the outer layer 2 is made of modified PPS resin. The modified PPS resin includes the following raw material components: 85 kg of PPS resin (Toray A900), 12 kg of HIPS resin prepared in [Preparation Example 1], 0.6 kg of antioxidant 1010 and 0.4 kg of antioxidant 168, and 2 kg of silica masterbatch.

[0066] In this embodiment, the preparation method of the modified PPS biaxially oriented film includes the following steps:

[0067] PPS resin, PPO resin, antioxidant 1010, antioxidant 168 and silica masterbatch

[0068] After mixing the pellets, melt extrusion and pelletization were carried out at 295°C to obtain modified PPS resin;

[0069] The modified PPS resin was fed into extruder A, and the PPS resin was fed into extruder B. The modified PPS resin in extruder A was melted at 305°C and evenly distributed to the upper and lower flow channels of the die distributor. The PPS resin in extruder B was melted at 305°C and distributed to the middle flow channel of the die distributor. Then, a sheet with a thickness of 200 μm was cast.

[0070] The sheet was biaxially stretched, with the stretching ratio of longitudinal stretching and transverse stretching both being 3 times, to obtain

[0071] Modified PPS biaxially oriented film.

[0072] [Example 3]

[0073] A modified PPS biaxially oriented film, which differs from [Example 2] in that:

[0074] In this embodiment, the HIPS resin is the HIPS resin prepared in [Preparation Example 2].

[0075] [Example 4]

[0076] A modified PPS biaxially oriented film, which differs from [Example 2] in that:

[0077] In this embodiment, the HIPS resin is the HIPS resin prepared in [Preparation Example 3].

[0078] [Example 5]

[0079] A modified PPS biaxially oriented film, which differs from [Example 2] in that:

[0080] In this embodiment, the HIPS resin is the HIPS resin prepared in [Preparation Example 4].

[0081] [Example 6]

[0082] A modified PPS biaxially oriented film differs from Example 2 in that a composition of PPO resin and HIPS resin obtained in Preparation Example 1 is used as a toughening resin in this embodiment, and the amount of PPO resin used is 3 kg, while the weight ratio of the composition of HIPS resin obtained in Preparation Example 1 is 9 kg.

[0083] Comparative Example

[0084] [Comparative Example 1]

[0085] A modified PPS biaxially oriented film, which differs from [Example 2] in that:

[0086] The HIPS resin prepared in [Preparation Example 1] was not added to the modified PPS resin.

[0087] [Comparative Example 2]

[0088] A modified PPS biaxially oriented film, which differs from [Example 2] in that:

[0089] The HIPS resin in the modified PPS resin is replaced by an equal amount of maleic anhydride grafted acrylonitrile-butadiene-styrene copolymer.

[0090] [Comparative Example 3]

[0091] A modified PPS biaxially oriented film, which differs from [Example 2] in that the thickness ratio of the core layer to the outer layer is 8:1.

[0092] Performance testing

[0093] 1. Elongation at break: Tested in accordance with ISO 527, test speed 50 mm / min.

[0094] 2. Dielectric constant: Tested in accordance with IEC 60250. Test conditions: 23°C, 60% RH, 1 MHz.

[0095] 3. Dissipation factor: Tested in accordance with IEC 60250, test conditions: 23°C, 60% RH, 1MHz.

[0096] 4. Thermal expansion coefficient: tested in accordance with ISO 11359-2.

[0097]

[0098] By comparing Example 1 with Comparative Example 1 and combining the data in Table 1, it can be seen that the addition of PPO resin to the outer layer 2 of the modified PPS biaxially oriented film can increase the elongation at break of the modified PPS biaxially oriented film and improve the film-forming properties of the modified PPS biaxially oriented film. At the same time, it will basically not affect the dielectric properties of the modified PPS biaxially oriented film. In addition, it can also improve the heat resistance of the modified PPS biaxially oriented film to a certain extent.

[0099] By comparing Examples 2-5 with Comparative Example 1 and combining the data in Table 1, it can be seen that the addition of HIPS resin to the outer layer 2 of the modified PPS biaxially oriented film can increase the elongation at break of the modified PPS biaxially oriented film and improve the film-forming properties of the modified PPS biaxially oriented film, while basically not affecting the dielectric properties of the modified PPS biaxially oriented film.

[0100] By comparing Example 2 with Comparative Example 2 and combining the data in Table 1, it can be seen that compared with modifying the outer layer 2 of the modified PPS biaxially oriented film by adding HIPS resin, although the addition of maleic anhydride grafted styrene-butadiene block copolymer to the outer layer 2 of the modified PPS biaxially oriented film can increase the elongation at break of the modified PPS biaxially oriented film and improve the film-forming properties of the modified PPS biaxially oriented film, the dielectric properties of the modified PPS biaxially oriented film are simultaneously improved, which is not conducive to obtaining a modified PPS biaxially oriented film with low dielectric properties. Moreover, the heat resistance of the modified PPS biaxially oriented film is also reduced.

[0101] By comparing Example 2 with Comparative Example 3 and combining the data in Table 1, it can be seen that when the ratio of the outer layer 2 to the core layer 1 is less than 1:3, the elongation at break of the modified PPS biaxially oriented film is improved but not significantly, which is not conducive to improving the film-forming properties of the modified PPS biaxially oriented film.

[0102] Comparing Examples 2-5 with Example 1 and combining the data in Table 1, it can be seen that the HIPS resin in Example 2-4 has a superior toughening effect on the modified PPS biaxially oriented film than the PPO resin, and the addition of the HIPS resin in Example 2-3 has little effect on the dielectric properties and heat resistance of the modified PPS biaxially oriented film. However, due to the low amount of α,ω-dihydroxypolysiloxane incorporated into the HIPS resin in Example 4, the heat resistance of the modified PPS biaxially oriented film is reduced. The HIPS resin in Example 5 has a toughening effect comparable to that of the PPO resin on the modified PPS biaxially oriented film and has little effect on the dielectric properties of the modified PPS biaxially oriented film. The film's heat resistance is comparable to that of the modified PPS biaxially oriented film in Example 1. In summary, when using HIPS resin as a toughening agent for modified PPS biaxially oriented film, it is preferred to use the HIPS resin in Examples 2-3 to modify the outer layer 2 of the modified PPS biaxially oriented film, as this is beneficial for obtaining a PPS biaxially oriented film with excellent toughness, low dielectric properties, and good heat resistance.

[0103] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A modified PPS biaxially oriented film, characterized in that: The invention comprises a core layer (1) and outer layers (2) arranged on the upper and lower surfaces of the core layer (1), wherein the thickness ratio of the core layer (1) to the outer layer (2) is 3:(1-1.5), and the core layer (1) is made of PPS resin, and the outer layer (2) is made of modified PPS resin; wherein the modified PPS resin comprises the following raw material components: 80-85 parts by weight of PPS resin, 12-18 parts by weight of toughening agent, 1-2 parts by weight of antioxidant and 1-2 parts by weight of anti-sticking agent, and the toughening agent comprises HIPS resin; The preparation method of the HIPS resin comprises the following steps: uniformly dispersing 85-92 parts by weight of styrene, 5.5-6.2 parts by weight of toughening rubber, and 1.8-2.6 parts by weight of a compatibilizer in 35-50 parts by weight of a solvent; then dropwise adding 1-2 parts by weight of an initiator; and firstly stirring and reacting at 100-110° C. for 0.5-0.8 hours at a stirring speed of 5-10 r / min under a pressure of 0.3-0.4 MPa; then stirring and reacting at 120-140° C. for 1.5-2 hours at a stirring speed of 30-35 r / min; and then stirring and reacting at 155-165° C. for 1.5-2 hours at a stirring speed of 5-10 r / min; and finally, recovering unreacted styrene and solvent, and granulating the material to obtain the HIPS resin. The toughening rubber comprises a styrene-butadiene diblock copolymer and an α,ω-dihydroxy polysiloxane, wherein the weight ratio of the styrene-butadiene diblock copolymer to the α,ω-dihydroxy polysiloxane is 1:(1-1.5); The compatibilizer is styrene-glycidyl methacrylate copolymer, and the mass fraction of epoxy groups in the styrene-glycidyl methacrylate copolymer is 3-6%.

2. A modified PPS biaxially oriented film according to claim 1, characterized in that: The toughening agent is a composition of PPO resin and HIPS resin, and the weight ratio of the PPO resin to the HIPS resin is 1: (3-4).

3. A modified PPS biaxially oriented film according to claim 1, characterized in that: The viscosity of the α,ω-dihydroxy polysiloxane is 550-650 cs.

4. A modified PPS biaxially oriented film according to claim 1, characterized in that: The initiator is at least one of diisopropylbenzene hydroperoxide, isopropylbenzene hydroperoxide and tert-butyl hydroperoxide.

5. A modified PPS biaxially oriented film according to any one of claims 1 to 4, characterized in that: The antioxidant is a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of the antioxidant 1010 to the antioxidant 168 is 3:(1-2).

6. A modified PPS biaxially oriented film according to any one of claims 1 to 4, characterized in that: The anti-sticking agent is silicon dioxide masterbatch.

7. The method for preparing a modified PPS biaxially oriented film according to any one of claims 1 to 6, characterized in that: The following steps are involved: PPS resin, toughening agent, antioxidant and anti-sticking agent are mixed, melt-extruded and granulated to obtain modified PPS resin; The modified PPS resin is fed into extruder A, and the PPS resin is fed into extruder B. The modified PPS resin in extruder A is melted and evenly distributed to the upper and lower flow channels of the die distributor. The PPS resin in extruder B is melted and distributed to the middle flow channel of the die distributor. The sheets are then cast to obtain a biaxially oriented modified PPS film.

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