Low-rainbow optical polyester film

Abstract

The utility model belongs to the technical field of films, and relates to a low-rainbow optical polyester film which comprises a core layer, a first surface layer located on one side of the core layer and a second surface layer located on the other side of the core layer, the core layer is provided with scattering particles A, and the particle size of the scattering particles A is 1-20 microns; the first surface layer is provided with scattering particles B, and the particle size of the scattering particles B is 0.5-5 [mu] m; the second surface layer is provided with scattering particles C, and the particle size of the scattering particles C is 0.5-10 [mu] m. The film obtained by the utility model is an optical polyester film with excellent optical performance and low rainbow lines.

Description

Technical Field

[0001] The utility model belongs to the technical field of films and relates to a low-rainbow optical polyester film. Background Art

[0002] PET polyester is widely used in the field of biaxial stretching due to the high symmetry of its molecular chain structure and the rigidity of its benzene ring. BOPET biaxially stretched optical polyester film has been rapidly developed due to its high transparency, non-toxic and odorless, high tensile strength, good stiffness, flexural resistance, excellent optical properties, oxygen barrier and moisture barrier properties. From reflective films, diffusion films, and prism films in the backlight modules of flat panel displays to thin optical polyester films that protect or replace TAC in liquid crystal display modules. However, PET polyester film will bend during biaxial stretching, which makes the polyester film have the characteristics of birefringence. In the case of a birefringent oriented polyester film on one side of the polarizer, the linearly polarized light emitted from the backlight unit or polarizer is incident on the birefringent BOPET polyester film, and becomes elliptically polarized light after transmission, resulting in a halo phenomenon, which also restricts the application of BOPET polyester film in liquid crystal display panels and touch panels. Patent CN201980065253.8 discloses a liquid crystal display device, a polarizing plate, and a polarizing plate protective film that can suppress the occurrence of rainbow spots and improve visibility in a liquid crystal display device with a backlight source composed of white light-emitting diodes, even when a polyethylene terephthalate resin film is used as a polarizing plate protective film that is a component of a polarizing plate. However, in order to achieve the purpose of low rainbow in this patent, it is necessary to make major adjustments to the stretching process, and the mechanical strength of the film is reduced, which limits the application scenarios.

[0003] At present, many studies have been done on the stretching process of PET in the prior art to improve the rainbow spot phenomenon, but the adjustment of these processes will lose the mechanical and optical properties of the film, which is not conducive to subsequent processing. In summary, how to provide an optical polyester film with excellent optical properties and low rainbow spots has become a problem that technicians in this field need to solve. Utility Model Content

[0004] The present application provides a low-rainbow optical polyester film, which is an optical polyester film with excellent optical properties and low rainbow patterns.

[0005] In order to achieve the above technical purpose, the technical solution adopted in the present application is a low rainbow optical polyester film, comprising a core layer, a first surface layer located on one side of the core layer, and a second surface layer located on the other side of the core layer.

[0006] The core layer is provided with scattering particles A, and the particle size of the scattering particles A is 1 μm to 20 μm;

[0007] The first surface layer is provided with scattering particles B, and the particle size of the scattering particles B is 0.5 μm to 5 μm;

[0008] The second surface layer is provided with scattering particles C, and the particle size of the scattering particles C is 0.5 μm to 10 μm.

[0009] As an improved technical solution of the present application, the thickness D1 of the core layer is 10μm~70μm, the thickness of the first surface layer D2 is 2μm~35μm, and the thickness of the second surface layer D3 is 3μm~35μm; the relationship between the thickness D1 of the core layer, the thickness D2 of the first surface layer and the thickness D3 of the second surface layer is D1=D2+D3.

[0010] As an improved technical solution of the present application, the total haze of the low rainbow optical polyester film is 0.5% to 5%, and the internal haze is 0.1% to 4%.

[0011] As an improved technical solution of the present application, the thickness of the low rainbow optical polyester film is 20 μm to 140 μm.

[0012] As an improved technical solution of the present application, the scattering particles are organic silicon particles, inorganic silicon particles or organic PMMA particles.

[0013] As an improved technical solution of the present application, the low rainbow optical polyester film has a phase delay of 1 nm to 1000 nm.

[0014] Beneficial Effects

[0015] By adding scattering particles of different particle sizes to the core layer, the first surface layer and the second surface layer, light is refracted multiple times through the surface of the tiny particles, increasing transparency and achieving a uniform light effect to offset the birefringence of the biaxially stretched polyester; at the same time, by controlling the coating thickness of the core layer, the first surface layer and the second surface layer, the total haze of the low rainbow optical polyester film is 0.5% to 5%, and the internal haze is 0.1% to 4%. Thus, it has better optical properties. The low rainbow optical polyester film provided by the utility model has a lower phase delay, better optical properties, and no halo phenomenon under polarized light, and can be applied to liquid crystal display panels, touch panels and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of the low rainbow optical polyester film of the present application is shown.

[0017] In the figure, 1, core layer; 2, first surface layer; 3, second surface layer; 101, scattering particle A; 201, scattering particle B; 301, scattering particle C. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0019] like Figure 1 As shown, the present application provides a low rainbow optical polyester film, including a core layer 1, a first surface layer 2 located on one side of the core layer 1, and a second surface layer 3 located on the other side of the core layer 1, the core layer 1 is provided with scattering particles A 101, the first surface layer 2 is provided with scattering particles B 201, and the second surface layer 3 is provided with scattering particles C 301. By adding scattering particles of different particle sizes to the core layer 1, the first surface layer 2 and the second surface layer 3, light is refracted multiple times through the surface of tiny particles, the transparency is increased, and the uniform light effect is achieved to offset the birefringence phenomenon of the biaxially stretched polyester.

[0020] The particle size of scattering particle A 101 is 1 μm to 20 μm, the particle size of scattering particle B 201 is 0.5 μm to 5 μm, and the particle size of scattering particle C 301 is 0.5 μm to 10 μm. The purpose of the size of scattering particle A 101, scattering particle B 201 and scattering particle C 301 in the present application is to have good compatibility with polyester materials, and these particle sizes can have good scattering and refraction effects.

[0021] Furthermore, the thickness D1 of the core layer 1 is 10μm to 70μm, the thickness of the first surface layer D2 is 2μm to 35μm, and the thickness of the second surface layer D3 is 3μm to 35μm; the relationship between the thickness D1 of the core layer, the thickness D2 of the first surface layer and the thickness D3 of the second surface layer is D1=D2+D3, so as to achieve good adhesion and non-delamination between the core layer 1 and the first surface layer 2 and the second surface layer 3, and at the same time make the scattering particles have a better scattering effect.

[0022] By designing the thickness of the core layer 1, the first surface layer 2, and the second surface layer 3, and preferably the size of the scattering particles A 101, the scattering particles B 201, and the scattering particles C 301, most of the scattering particles are located inside the core layer 1, the first surface layer 2, and the second surface layer 3. When light passes through the polyester and the scattering particles inside the film, refraction and scattering will occur, thereby generating internal haze. The internal haze reflects the deviation of light when light passes through the film, and also reflects the main effect of adding scattering particles A 101, scattering particles B 201, and scattering particles C 301 in the present invention.

[0023] The thickness of the low rainbow optical polyester film is 20 μm to 140 μm. The purpose is: on the one hand, to apply the main thickness in liquid crystal display panels and touch panels, and on the other hand, to control the scattering particle protrusions on the surface of the film by using the thickness design of the interlayer structure to achieve excellent optical performance.

[0024] Furthermore, the scattering particles are organic silicon particles, inorganic silicon particles or organic PMMA particles. The refractive index of organic silicon particles, inorganic silicon particles or organic PMMA particles is different from that of polyester, so a better scattering effect can be achieved.

[0025] Furthermore, the low rainbow optical polyester film has a phase retardation of 1 nm to 1000 nm.

[0026] Example 1

[0027] The utility model discloses a low rainbow optical polyester film, comprising a core layer 1, a first surface layer 2 located at one side of the core layer 1, and a second surface layer 3 located at the other side of the core layer 1; the core layer 1 is formed by polyester chips (model FG600, company: Yizheng Chemical Fiber) and scattering particles A101 (model: SS-20, inorganic silicon particles, company: Japan Tosoh, particle size 7.5μm), the first surface layer 2 is formed by polyester chips (model FG600, company: Yizheng Chemical Fiber) and scattering particles B201 (model: MR-2G, PMMA particles, company: Soken Chemical, particle size 1μm), and the second surface layer 3 is formed by polyester chips (model FG600, company: Yizheng Chemical Fiber) and scattering particles C301 (model: TP905A, organic silicon particles, company: Yongqi Materials, particle size 5μm). After the film is formed by biaxial stretching, the thickness of the core layer 1 is 50 μm, the thickness of the first surface layer 2 is 20 μm, and the thickness of the second surface layer 3 is 30 μm.

[0028] The low rainbow optical polyester film of this embodiment has a thickness of 100 μm, a total haze of 5%, an internal haze of 3.5%, and a phase retardation of 400 nm.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low rainbow optical polyester film, comprising a core layer, a first surface layer located on one side of the core layer, and a second surface layer located on the other side of the core layer, characterized in that: The core layer is provided with scattering particles A, the particle size of the scattering particles A is 1 μm to 20 μm; the scattering particles A are inorganic silicon particles; The first surface layer is provided with scattering particles B, the particle size of the scattering particles B is 0.5 μm to 5 μm; the scattering particles B are PMMA particles; The second surface layer is provided with scattering particles C, the particle size of the scattering particles C is 0.5 μm to 10 μm; the scattering particles C are organic silicon particles.

2. A low rainbow optical polyester film according to claim 1, characterized in that: The thickness D1 of the core layer is 10 μm to 70 μm, the thickness of the first surface layer D2 is 2 μm to 35 μm, and the thickness of the second surface layer D3 is 3 μm to 35 μm; the relationship among the thickness D1 of the core layer, the thickness D2 of the first surface layer and the thickness D3 of the second surface layer is D1=D2+D3.

3. A low rainbow optical polyester film according to claim 1, characterized in that: The low rainbow optical polyester film has a total haze of 0.5% to 5% and an internal haze of 0.1% to 4%.

4. A low rainbow optical polyester film according to claim 1, characterized in that: The low rainbow optical polyester film has a thickness of 20 μm to 140 μm.

5. The low rainbow optical polyester film according to claim 1, characterized in that: The low rainbow optical polyester film has a phase retardation of 1 nm to 1000 nm.

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