Open master batch for ultra-smooth optical film and optical film

Abstract

The invention relates to the technical field of optical thin film materials, particularly discloses an opening master batch for an ultra-smooth optical film, and also discloses an optical thin film prepared from the opening master batch. According to the invention, the anti-blocking agent powder is modified to prepare the modified anti-blocking agent powder, and then the modified anti-blocking agent powder is used for preparing the anti-blocking master batch, so that the anti-blocking master batch in which the anti-blocking agent powder is uniformly distributed is obtained. The optical film further prepared by adopting the opening master batch for the ultra-smooth optical film, provided by the invention, is good in opening property, the films are not adhered, and rolling and slitting are simple and easy. And the surface opening agent of the optical thin film is uniformly distributed, and the thin film is low in roughness, high in flatness, smoother, less in surface defect and excellent in optical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of optical thin film materials, and particularly to an opening masterbatch for a super-smooth optical film, and also to an optical film prepared by using the opening masterbatch. Background Art

[0002] Plastic films are prone to adhesion, mainly for two reasons: First, there are a large number of exposed molecular chains on the surface of the film after forming. When two films are closed, the exposed molecular chains are entangled with each other, making the films unable to be separated. Second, a vacuum tight state is formed between the films after closing, making it difficult to separate the films. To solve the adhesion problem of plastic films, adding inorganic anti-blocking and opening agents to the films is a common method. Adding opening agents can cause particle protrusions on the surface of the film, thereby allowing air to penetrate into the film and reducing the negative pressure between the films, making it easy to separate the films. At the same time, the particle protrusions generated on the film surface can reduce the contact area between the exposed molecular chains on the film surface, hinder the entanglement of molecular chains between layers of the film, and prevent the adhesion of the films.

[0003] However, the protrusions on the film surface generated by adding inorganic anti-blocking and opening agents to the film will also cause a decrease in the roughness and flatness of the film surface, resulting in a lower smoothness of the film surface. When applied to optical films, it will affect the optical performance of the prepared optical films. Therefore, when preparing super-smooth films, it is necessary to fully consider the opening property of the film, and at the same time, it is advisable to select nano-powders with finer particle sizes as opening agents as much as possible. However, due to the strong intermolecular force of nano-powders, they are extremely prone to agglomeration. This problem will cause a decrease in the opening property of the prepared film and a decrease in the winding and slitting performance; the protrusions generated at the agglomeration sites of the powders are larger and more obvious, which is likely to cause a series of problems such as film surface defects and a decrease in optical performance.

[0004] Based on the above existing problems, the present invention aims to develop an opening masterbatch for a super-smooth optical film to obtain an optical film with excellent opening performance and optical performance. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide an opening masterbatch for a super-smooth optical film, and also to provide an optical film prepared by using the opening masterbatch.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is: An opening masterbatch for a super-smooth optical film, the preparation raw materials of which include the following raw materials in parts by weight:

[0007]

[0008] As an embodiment of the present invention, the preparation raw materials of the opening masterbatch for a super-smooth optical film include the following raw materials in parts by weight:

[0009]

[0010] As an embodiment of the present invention, the opening masterbatch for the ultra-smooth optical film is prepared by raw materials including the following raw materials in parts by weight:

[0011]

[0012] As an embodiment of the present invention, the optical grade polyethylene terephthalate is a pellet with an intrinsic viscosity of 0.645 to 0.655 dL / g.

[0013] As an embodiment of the present invention, the polyethylene terephthalate for bottles is a powder with an intrinsic viscosity of 0.675 to 0.685 dL / g.

[0014] As an embodiment of the present invention, the modified opening agent powder adopts silicon dioxide and / or calcium carbonate.

[0015] The opening agent powder is spherical or quasi-spherical in structure, and the average particle size of the opening agent powder is 30nm to 80nm.

[0016] As an embodiment of the present invention, the modifier used for modification is a compound of polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone. Preferably, polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone are mixed and compounded in a mass ratio of (40-60): (25-40): (15-20). Further preferably, polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone are mixed and compounded in a mass ratio of (40-50): (30-40): (15-20). Even more preferably, polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone are mixed and compounded in a mass ratio of (40-50): (33-40): (17-20).

[0017] As an embodiment of the present invention, the preparation steps of the modified opening agent powder are: adding the opening agent powder and the modifier to the solvent, stirring and then ultrasonically treating to fully disperse the opening agent powder, then evaporating the solvent, and then grinding and sieving to obtain the modified opening agent powder. Preferably, ethanol is used as the solvent.

[0018] As an embodiment of the present invention, multi-stage screening is adopted during screening, and five-stage screening is preferably adopted.

[0019] As a specific implementation scheme of the present invention, 5 layers of sieves are used for screening, and the sieves are stacked in sequence from coarse to fine, preferably in the order of 10000 mesh, 20000 mesh, 30000 mesh, 40000 mesh, and 50000 mesh.

[0020] As an embodiment of the present invention, the mass ratio of the solvent, the opening agent powder and the modifier is (85-97): (2-10): (1-5); further, the mass ratio of the solvent, the opening agent powder and the modifier is (90-95): (5-10): (1-3).

[0021] As an embodiment of the present invention, the antioxidant can be selected from at least one of BASF's antioxidant 1010, antioxidant 168, antioxidant 1076, or Sumitomo Chemical's antioxidant GA-80 and TP-D.

[0022] The present invention provides a method for preparing the open masterbatch for the ultra-smooth optical film, which is prepared by a twin-screw mixing method, comprising the steps of:

[0023] S1: Weigh each raw material according to weight proportion;

[0024] Add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the polyethylene terephthalate powder for bottles, the modified opening agent powder and the antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment;

[0025] S2: The material is melted and mixed in a twin-screw compounding equipment, and then extruded from the head of the twin-screw compounding equipment. It is first cooled and pulled, and then enters the pelletizing and drying system. After pelletizing and drying, the open masterbatch for ultra-smooth optical film is obtained.

[0026] Among them, the screw temperature of the twin-screw compounding equipment is 220-260°C, the screw speed is 200-380rpm, and the thread combination is a strong shear combination.

[0027] The present invention provides application of the opening masterbatch for the ultra-smooth optical film of the present invention in the preparation of an optical film.

[0028] The present invention further provides an optical film, comprising the open masterbatch for the ultra-smooth optical film provided by the present invention. Specifically, the optical film is an ABA three-layer co-extrusion structure, comprising a core layer (B) and surface layers (A) arranged on both sides of the core layer;

[0029] The raw materials for preparing the surface layer include film-grade polyethylene terephthalate and the opening masterbatch for the ultra-smooth optical film, wherein the mass percentage content of the opening masterbatch for the ultra-smooth optical film in the raw materials for preparing the surface layer is 2 to 10%;

[0030] The raw material for preparing the core layer is film-grade polyethylene terephthalate;

[0031] The total mass of the skin layer accounts for 20-30% of the total mass of the core layer and the skin layer.

[0032] The present invention provides a method for preparing the optical film, comprising the steps of:

[0033] (1) adding the raw material for preparing the surface layer from the auxiliary extruder hopper of the extrusion casting machine as the surface layer material; adding the raw material for preparing the core layer from the main extruder hopper of the extrusion casting machine as the core layer material;

[0034] (2) The surface layer material is extruded through an auxiliary extruder, and the core layer material is extruded through a main extruder, and then melted and mixed in an extrusion casting machine, and then extruded from a die head to obtain a co-extruded cast sheet with a three-layer structure;

[0035] (3) The co-extruded cast sheet is cut into cast sheets with a size of 130 mm*130 mm, and the cast sheet is subjected to bidirectional synchronous stretching and shaping to obtain an ultra-smooth optical film.

[0036] Wherein, in step (2), the temperature of the auxiliary extruder and the main extruder is set in the range of 270-290°C, but the specific set temperatures of the auxiliary extruder and the main extruder may be different. The rotation speed of the main extruder is 170-190 rpm, and the rotation speed of the auxiliary extruder is 50-90 rpm.

[0037] In step (3), the preheating temperature of the biaxial synchronous stretching is 100-120° C., the preheating time is 10-25 s, the longitudinal stretching ratio is 3.3-3.8, and the transverse stretching ratio is 3.3-3.8.

[0038] In step (3), the setting temperature is 200-220° C., and the setting time is 2-6 seconds.

[0039] Nano-scale powders are prone to agglomeration and are difficult to disperse into single particles due to the strong intermolecular forces, which will affect the opening effect and comprehensive performance of the optical film. At present, when using the screw method to prepare opening masterbatch, a higher shear mixing effect is often required, which places too high a requirement on the equipment. Even most of the current equipment cannot achieve the purpose of directly dispersing nano-scale powders in a fully uniform and single particle state. Therefore, the dispersion problem of nano-scale powders is still difficult to solve effectively.

[0040] In view of the dispersion problem of the nano-scale powders mentioned above, in the present invention, the opening agent powder is first modified, and the modified opening agent powder is made and then used to prepare the opening masterbatch. Through the modification, the interfacial tension of the nano-scale powder is effectively reduced, a charge barrier is formed, and the steric hindrance between molecules is increased; at the same time, the intermolecular force is reduced, so that the opening agent powder is easy to disperse and does not agglomerate, and the dispersion stability is greatly improved. When preparing the opening masterbatch, the modified opening agent powder is used and prepared by a twin-screw mixing method, which effectively avoids the secondary agglomeration of the opening agent powder and is conducive to obtaining the opening masterbatch with uniform distribution of the opening agent powder.

[0041] The optical film further prepared by using the opening masterbatch for the ultra-smooth optical film provided by the present invention has good opening property, no adhesion between the films, and is easy to roll up and cut. The surface opening agent of the optical film is evenly distributed, the roughness of the film is low, the flatness is high, the film is smoother, the surface defects are few, and the optical performance is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a TEM image of the opening agent powder raw material in Example 1 of the present invention;

[0043] Figure 2 This is a TEM image of the modified opening agent powder obtained by processing in Example 1 of the present invention;

[0044] Figure 3 is a polarizing microscope picture of the ultra-smooth optical film obtained in Example 5 of the present invention;

[0045] Figure 4 is a polarizing microscope picture of the ultra-smooth optical film obtained in Example 6 of the present invention;

[0046] Figure 5 is a polarizing microscope picture of the ultra-smooth optical film obtained in Example 7 of the present invention;

[0047] Figure 6 This is a 3D surface roughness meter picture of the ultra-smooth optical film obtained in Example 5 of the present invention;

[0048] Figure 7 This is a 3D surface roughness meter picture of the ultra-smooth optical film obtained in Example 6 of the present invention;

[0049] Figure 8 This is a 3D surface roughness meter picture of the ultra-smooth optical film obtained in Example 7 of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is described in detail below through specific embodiments. The following embodiments are intended to further illustrate the content of the present invention in detail, but are not intended to limit the scope of protection of the claims of the present invention.

[0051] In the following examples, unless otherwise specified, all reagents used are commercially available products.

[0052] Example 1

[0053] This embodiment provides an opening masterbatch for an ultra-smooth optical film, and the raw materials for preparation are composed of the following raw materials in parts by weight:

[0054]

[0055] The optical grade polyethylene terephthalate is a pellet with an intrinsic viscosity of 0.650 dL / g.

[0056] The polyethylene terephthalate for bottles is a powder with an intrinsic viscosity of 0.680 dL / g.

[0057] The modified opening agent powder uses silicon dioxide, which has a spherical structure and an average particle size of 50nm. The modified modifier used is a compound of polyethylene glycol 400, sodium hexametaphosphate and polyvinyl pyrrolidone, which is mixed and compounded in a mass ratio of 50:33:17.

[0058] The preparation steps of the modified opening agent powder are as follows: add silica powder and modifier to ethanol solvent, stir for 30 minutes, then ultrasonically treat for 60 minutes to fully disperse the silica powder, then heat to 80°C to evaporate the ethanol, then grind and sieve, and use 5 layers of sieves for sieving. The sieves are set in the order of 10000 mesh, 20000 mesh, 30000 mesh, 40000 mesh, and 50000 mesh from coarse to fine. The obtained sieve under the sieve is the modified opening agent powder. Among them, the mass ratio of ethanol, silica powder, and modifier is 93:5:2.

[0059] Among them, the TEM images of the opening agent raw material and the modified opening agent powder obtained by treatment are shown in Figure 1 and Figure 2 The TEM image of the raw material of the anti-blocking agent shows that the powder has obvious agglomeration, but after the modification treatment, the powder of the anti-blocking agent is basically well dispersed and the agglomeration phenomenon is significantly improved.

[0060] The antioxidant used was antioxidant 1010 from BASF.

[0061] The preparation method of the open masterbatch for the ultra-smooth optical film adopts a twin-screw mixing method, comprising the steps of:

[0062] S1: Weigh each raw material according to weight proportion;

[0063] Add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the polyethylene terephthalate powder for bottles, the modified opening agent powder and the antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment;

[0064] S2: The material is melted and mixed in a twin-screw compounding equipment, and then extruded from the head of the twin-screw compounding equipment. It is first cooled and pulled, and then enters the pelletizing and drying system. After pelletizing and drying, the open masterbatch for ultra-smooth optical film is obtained.

[0065] Among them, the screw temperature of the twin-screw compounding equipment is 240-260°C, the screw speed is 300rpm, and the thread combination is a strong shear combination.

[0066] Example 2

[0067] This embodiment provides an opening masterbatch for an ultra-smooth optical film, and the raw materials for preparation are composed of the following raw materials in parts by weight:

[0068]

[0069] The raw materials used, optical grade polyethylene terephthalate and bottle polyethylene terephthalate, are the same as those in Example 1.

[0070] The modified opening agent powder uses calcium carbonate, which has a spherical structure and an average particle size of 60nm. The modified modifier used is a compound of polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone, which is mixed and compounded in a mass ratio of 50:33:17.

[0071] The preparation steps of the modified opening agent powder are as follows: add calcium carbonate powder and modifier to ethanol solvent, stir for 30 minutes, then ultrasonically treat for 60 minutes to fully disperse the calcium carbonate powder, then heat to 85°C to evaporate the ethanol, and then grind and screen, and use 5 layers of sieves for screening, the sieves are set in order from coarse to fine in 10000 mesh, 20000 mesh, 30000 mesh, 40000 mesh, 50000 mesh, and the obtained sieve under is the modified opening agent powder. Among them, the mass ratio of ethanol, calcium carbonate powder and modifier is 93:5:2.

[0072] The antioxidant used was Sumitomo Chemical's antioxidant GA-80.

[0073] The preparation method of the open masterbatch for the ultra-smooth optical film adopts a twin-screw mixing method, comprising the steps of:

[0074] S1: Weigh each raw material according to the weight ratio;

[0075] Add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the polyethylene terephthalate powder for bottles, the modified opening agent powder and the antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment;

[0076] S2: The material is melted and mixed in a twin-screw compounding equipment, and then extruded from the head of the twin-screw compounding equipment. It is first cooled and pulled, and then enters the pelletizing and drying system. After pelletizing and drying, the open masterbatch for ultra-smooth optical film is obtained.

[0077] Among them, the screw temperature of the twin-screw compounding equipment is 240-260°C, the screw speed is 300rpm, and the thread combination is a strong shear combination.

[0078] Example 3

[0079] This embodiment provides an opening masterbatch for an ultra-smooth optical film, and the raw materials for preparation are composed of the following raw materials in parts by weight:

[0080]

[0081] The raw materials used, optical grade polyethylene terephthalate and bottle polyethylene terephthalate, are the same as those in Example 1.

[0082] The modified opening agent powder uses the same opening agent powder as in Example 1, and the modified modifier used is a compound of polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone, which is mixed and compounded in a mass ratio of 40:40:20.

[0083] The preparation steps of the modified opening agent powder are as follows: add silica powder and modifier to ethanol solvent, stir for 30 minutes, then ultrasonically treat for 60 minutes to fully disperse the silica powder, then heat to 80°C to evaporate the ethanol, then grind and sieve, and use 5 layers of sieves for sieving. The sieves are set in the order of 10000 mesh, 20000 mesh, 30000 mesh, 40000 mesh, and 50000 mesh from coarse to fine. The obtained sieve under the sieve is the modified opening agent powder. Among them, the mass ratio of ethanol, silica powder, and modifier is 93:5:2.

[0084] The antioxidant used was antioxidant 1010 from BASF.

[0085] The preparation method of the open masterbatch for the ultra-smooth optical film adopts a twin-screw mixing method, comprising the steps of:

[0086] S1: Weigh each raw material according to weight proportion;

[0087] Add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the polyethylene terephthalate powder for bottles, the modified opening agent powder and the antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment;

[0088] S2: The material is melted and mixed in a twin-screw compounding equipment, and then extruded from the head of the twin-screw compounding equipment. It is first cooled and pulled, and then enters the pelletizing and drying system. After pelletizing and drying, the open masterbatch for ultra-smooth optical film is obtained.

[0089] Among them, the screw temperature of the twin-screw compounding equipment is 240-260°C, the screw speed is 300rpm, and the thread combination is a strong shear combination.

[0090] Example 4

[0091] This embodiment provides an opening masterbatch for an ultra-smooth optical film, and the raw materials for preparation are composed of the following raw materials in parts by weight:

[0092]

[0093] The raw materials used, optical grade polyethylene terephthalate and bottle polyethylene terephthalate, are the same as those in Example 1.

[0094] The modified opening agent powder uses the same opening agent powder as in Example 2, and the modified modifier used is a compound of polyethylene glycol 400, sodium hexametaphosphate, and polyvinyl pyrrolidone, which is mixed and compounded in a mass ratio of 40:40:20.

[0095] The preparation steps of the modified opening agent powder are as follows: add calcium carbonate powder and a modifier to an ethanol solvent, stir for 30 minutes, then perform ultrasonic treatment for 60 minutes to fully disperse the calcium carbonate powder, then heat to 85°C to evaporate the ethanol, and then grind and screen. The 5-layer sieve is used for screening. The sieves are set in the order of 10,000 mesh, 20,000 mesh, 30,000 mesh, 40,000 mesh, and 50,000 mesh from coarse to fine. The obtained sieve under the sieve is the modified opening agent powder. Among them, the mass ratio of ethanol, calcium carbonate powder, and modifier is 93:10:2.

[0096] The antioxidant used was Sumitomo Chemical's antioxidant GA-80.

[0097] The preparation method of the open masterbatch for the ultra-smooth optical film adopts a twin-screw mixing method, comprising the steps of:

[0098] S1: Weigh each raw material according to weight proportion;

[0099] Add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the polyethylene terephthalate powder for bottles, the modified opening agent powder and the antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment;

[0100] S2: The material is melted and mixed in a twin-screw compounding equipment, and then extruded from the head of the twin-screw compounding equipment. It is first cooled and pulled, and then enters the pelletizing and drying system. After pelletizing and drying, the open masterbatch for ultra-smooth optical film is obtained.

[0101] Among them, the screw temperature of the twin-screw compounding equipment is 240-260°C, the screw speed is 300rpm, and the thread combination is a strong shear combination.

[0102] The physical properties of the open masterbatch prepared in Examples 1-4 above were tested, and the results are shown in Table 1 below.

[0103] Table 1

[0104]

[0105] The open masterbatches prepared in the above Examples 1-4 were used to further prepare optical films, as shown in the following examples.

[0106] Example 5

[0107] This embodiment provides an optical film, which is prepared using the open masterbatch for the ultra-smooth optical film provided in Embodiment 1.

[0108] The optical film is an ABA three-layer co-extruded structure, comprising a core layer (B) and surface layers (A) arranged on both sides of the core layer, forming an ABA stacked structure.

[0109] The raw material for preparing the surface layer is composed of film-grade polyethylene terephthalate and the opening masterbatch for ultra-smooth optical film of Example 1, wherein the mass percentage content of the opening masterbatch for ultra-smooth optical film in the raw material for preparing the surface layer is 5%. The raw material for preparing the core layer is film-grade polyethylene terephthalate. The total mass of the surface layer accounts for 20% of the total mass of the core layer and the surface layer.

[0110] The method for preparing the optical film comprises the following steps:

[0111] (1) adding the raw material for preparing the surface layer from the auxiliary extruder hopper of the extrusion casting machine as the surface layer material; adding the raw material for preparing the core layer from the main extruder hopper of the extrusion casting machine as the core layer material;

[0112] (2) The surface layer material is extruded through an auxiliary extruder, and the core layer material is extruded through a main extruder, and then melted and mixed in an extrusion casting machine, and then extruded from a die head to obtain a co-extruded cast sheet with a three-layer structure; wherein the temperature of the auxiliary extruder and the main extruder is set within the range of 270 to 280° C., the rotation speed of the main extruder is 180 rpm, and the rotation speed of the auxiliary extruder is 60 rpm;

[0113] (3) The co-extruded cast sheet was cut into a cast sheet of 130 mm*130 mm in size, and the cast sheet was subjected to bidirectional synchronous stretching and shaping to obtain an ultra-smooth optical film. The preheating temperature of the bidirectional synchronous stretching was 105°C, the preheating time was 20 s, the longitudinal stretching ratio was 3.3, and the transverse stretching ratio was 3.3. The shaping temperature was 210°C, and the shaping time was 3 s.

[0114] The polarizing microscope picture of the ultra-smooth optical film obtained in this embodiment is shown in Figure 3 As shown, the 3D surface roughness tester picture is shown in Figure 6 shown.

[0115] Example 6

[0116] This embodiment provides an optical film, which is prepared using the open masterbatch for the ultra-smooth optical film provided in Embodiment 2.

[0117] The optical film is an ABA three-layer co-extruded structure, comprising a core layer (B) and surface layers (A) arranged on both sides of the core layer, forming an ABA stacked structure.

[0118] The raw material for preparing the surface layer is composed of film-grade polyethylene terephthalate and the opening masterbatch for ultra-smooth optical film of Example 2, wherein the mass percentage content of the opening masterbatch for ultra-smooth optical film in the raw material for preparing the surface layer is 5%. The raw material for preparing the core layer is film-grade polyethylene terephthalate. The total mass of the surface layer accounts for 25% of the total mass of the core layer and the surface layer.

[0119] The method for preparing the optical film comprises the following steps:

[0120] (1) adding the raw material for preparing the surface layer from the auxiliary extruder hopper of the extrusion casting machine as the surface layer material; adding the raw material for preparing the core layer from the main extruder hopper of the extrusion casting machine as the core layer material;

[0121] (2) The surface layer material is extruded through an auxiliary extruder, and the core layer material is extruded through a main extruder, and then melted and mixed in an extrusion casting machine, and then extruded from a die head to obtain a co-extruded cast sheet with a three-layer structure; wherein the temperature of the auxiliary extruder and the main extruder is set within the range of 270 to 280° C., the rotation speed of the main extruder is 180 rpm, and the rotation speed of the auxiliary extruder is 60 rpm;

[0122] (3) The co-extruded cast sheet was cut into a cast sheet of 130 mm*130 mm in size, and the cast sheet was subjected to bidirectional synchronous stretching and shaping to obtain an ultra-smooth optical film. The preheating temperature of the bidirectional synchronous stretching was 105°C, the preheating time was 20 s, the longitudinal stretching ratio was 3.3, and the transverse stretching ratio was 3.3. The shaping temperature was 210°C, and the shaping time was 3 s.

[0123] The polarizing microscope picture of the ultra-smooth optical film obtained in this embodiment is shown in Figure 4 As shown, the 3D surface roughness tester picture is shown in Figure 7 shown.

[0124] Example 7

[0125] This embodiment provides an optical film, which is prepared using the open masterbatch for the ultra-smooth optical film provided in Embodiment 3.

[0126] The optical film is an ABA three-layer co-extruded structure, comprising a core layer (B) and surface layers (A) arranged on both sides of the core layer, forming an ABA stacked structure.

[0127] The raw material for preparing the surface layer is composed of film-grade polyethylene terephthalate and the opening masterbatch for ultra-smooth optical film of Example 3, wherein the mass percentage content of the opening masterbatch for ultra-smooth optical film in the raw material for preparing the surface layer is 7%. The raw material for preparing the core layer is film-grade polyethylene terephthalate. The total mass of the surface layer accounts for 25% of the total mass of the core layer and the surface layer.

[0128] The method for preparing the optical film comprises the following steps:

[0129] (1) adding the raw material for preparing the surface layer from the auxiliary extruder hopper of the extrusion casting machine as the surface layer material; adding the raw material for preparing the core layer from the main extruder hopper of the extrusion casting machine as the core layer material;

[0130] (2) The surface layer material is extruded through an auxiliary extruder, and the core layer material is extruded through a main extruder, and then melted and mixed in an extrusion casting machine, and then extruded from a die head to obtain a co-extruded cast sheet with a three-layer structure; wherein the temperature of the auxiliary extruder and the main extruder is set within the range of 270 to 280° C., the rotation speed of the main extruder is 180 rpm, and the rotation speed of the auxiliary extruder is 60 rpm;

[0131] (3) The co-extruded cast sheet was cut into a cast sheet of 130 mm*130 mm in size, and the cast sheet was subjected to bidirectional synchronous stretching and shaping to obtain an ultra-smooth optical film. The preheating temperature of the bidirectional synchronous stretching was 105°C, the preheating time was 20 s, the longitudinal stretching ratio was 3.3, and the transverse stretching ratio was 3.3. The shaping temperature was 210°C, and the shaping time was 3 s.

[0132] The polarizing microscope picture of the ultra-smooth optical film obtained in this embodiment is shown in Figure 5 As shown, the 3D surface roughness tester picture is shown in Figure 8 shown.

[0133] The performance of the optical films provided in Examples 5-7 above was tested, and the results are shown in Table 2.

[0134] Table 2

[0135]

[0136] It can be seen from Table 2 that the optical films provided by Examples 5-7 have good opening performance, are characterized by low haze, high clarity, high light transmittance, excellent optical properties, low film roughness, high flatness, and are smooth.

[0137] from Figure 3-Figure 8 It can be seen that the surface particles of the optical films provided in Examples 5-7 are evenly distributed, of similar size, and the film surface is relatively smooth with little roughness. Figure 5 It shows that there are some large particles on the surface of the film provided by Example 7, but the overall film surface is also very smooth.

[0138] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. An opening masterbatch for ultra-smooth optical film, characterized in that: The preparation raw materials include the following raw materials in parts by weight:

2. The open masterbatch according to claim 1, characterized in that: The preparation raw materials include the following raw materials in parts by weight:

3. The open masterbatch according to claim 1 or 2, characterized in that: The preparation raw materials include the following raw materials in parts by weight:

4. The open masterbatch according to any one of claims 1 to 3, characterized in that: The modified opening agent powder adopts silicon dioxide and / or calcium carbonate, and the average particle size of the opening agent powder is 30nm to 80nm; The modifier used for modification is a compound of polyethylene glycol 400, sodium hexametaphosphate and polyvinyl pyrrolidone, preferably polyethylene glycol 400, sodium hexametaphosphate and polyvinyl pyrrolidone are mixed in a mass ratio of (40-60): (25-40): (15-20).

5. The open masterbatch according to claim 4, characterized in that: The preparation steps of the modified opening agent powder are as follows: adding the opening agent powder and the modifier to the solvent, stirring and then ultrasonically treating, then evaporating the solvent, and then grinding and sieving to obtain the modified opening agent powder; Wherein, the mass ratio of the solvent, the opening agent powder and the modifier is (85-97): (2-10): (1-5); Preferably, ethanol is used as the solvent.

6. A method for preparing the open masterbatch according to any one of claims 1 to 5, characterized in that: The preparation is carried out by a twin-screw mixing method, comprising the steps of: S1: Weigh the raw materials according to their weight proportions, add the optical grade polyethylene terephthalate pellets from the main feeding port of the twin-screw compounding equipment, mix the bottle polyethylene terephthalate powder, modified opening agent powder and antioxidant evenly, and then add them from the side feeding port of the twin-screw compounding equipment; S2: The materials are melted and mixed in a twin-screw compounding device, and then extruded from the die head of the twin-screw compounding device, pelletized and dried to obtain an open masterbatch for an ultra-smooth optical film; Among them, the screw temperature of the twin-screw compounding equipment is 220-260°C, the screw speed is 200-380rpm, and the thread combination is a strong shear combination.

7. Use of the open masterbatch for ultra-smooth optical film according to any one of claims 1 to 5 in the preparation of optical films.

8. An optical film, characterized in that: The optical film is an ABA three-layer co-extruded structure, including a core layer and surface layers arranged on both sides of the core layer; The raw materials for preparing the surface layer include film-grade polyethylene terephthalate and the opening masterbatch for the ultra-smooth optical film according to any one of claims 1 to 5, wherein the mass percentage content of the opening masterbatch for the ultra-smooth optical film in the raw materials for preparing the surface layer is 2 to 10%; The raw material for preparing the core layer is film-grade polyethylene terephthalate; The mass of the skin layer accounts for 20-30% of the total mass of the core layer and the skin layer.

9. The method for preparing an optical film according to claim 8, characterized in that: Includes steps: (1) adding the raw material for preparing the surface layer from the auxiliary extruder hopper of the extrusion casting machine as the surface layer material; adding the raw material for preparing the core layer from the main extruder hopper of the extrusion casting machine as the core layer material; (2) The surface layer material is extruded through an auxiliary extruder, and the core layer material is extruded through a main extruder, and then melted and mixed in an extrusion casting machine, and then extruded from a die head to obtain a co-extruded cast sheet with a three-layer structure; (3) The co-extruded cast sheet is cut, then bidirectionally stretched and shaped to obtain an ultra-smooth optical film.

10. The method for preparing an optical film according to claim 9, characterized in that: In step (2), the temperatures of the auxiliary extruder and the main extruder are both set to 270-290° C., the rotation speed of the main extruder is 170-190 rpm, and the rotation speed of the auxiliary extruder is 50-90 rpm; In step (3), the preheating temperature of the biaxial synchronous stretching is 100 to 120° C., the preheating time is 10 to 25 seconds, the longitudinal stretching ratio is 3.3 to 3.8, and the transverse stretching ratio is 3.3 to 3.8; In step (3), the setting temperature is 200-220° C., and the setting time is 2-6 seconds.

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