Pre-coated low-rainbow optical polyester film
By adding scattering particles and nanoparticles of different sizes to different layers of the PET polyester film, the crystallization orientation of the polyester segments is changed and the birefringence phenomenon is offset through the reflection and refraction of light, thus solving the problem of biaxial stretch processing of the film. The high optical properties and adhesion of low-rainbow optical polyester films are achieved by eliminating the problem of rainbow streaks that occurs in polyester films.
Patent Information
- Application Number
- CN202420181334.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-25
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-01-25
AI Technical Summary
The existing PET polyester films have birefringence during bidirectional stretching processing, resulting in the emergence of rainbow patterns, limiting their application in liquid crystal display panels and polarizers.
It adopts a pre-coated low rainbow optical polyester film structure, including a core layer, a first surface layer, a second surface layer, a first adhesive layer and a second adhesive layer. Scattering particles and nanometer particles of different particle sizes are added to each layer. particles to change the crystallographic orientation of polyester chain segments and offset birefringence through reflection and refraction of light.
It achieves the low rainbow effect of polyester film, enhances the optical properties and adhesion, and avoids the rainbow phenomenon under polarized light. It is suitable for polarizers, screen protection and other fields.
Smart Images
Figure CN222372456U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of films, in particular to a pre-coated low-rainbow optical polyester film which can be used for post-processing coating, and specifically relates to a pre-coated 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 the molecular chain structure and the rigidity of the benzene ring. After biaxial stretching, PET polyester has high mechanical strength, excellent optical properties and electrical insulation properties. The product meets environmental protection and health requirements and can be used in optoelectronic display, packaging, ideas, photosensitivity, new energy and other fields. The film produced by the biaxial stretching production process has undergone a certain stretching in the longitudinal and transverse directions, which changes the arrangement of molecules or chain segments, and undergoes different heating processes during the processing. Its main properties have changed significantly, such as the mechanical properties of the film, such as tensile strength and elastic modulus, which are significantly enhanced, and the aging resistance is improved, which improves the transparency of the film. However, during the biaxial stretching process of polyester, the stretching orientation makes PET an anisotropic material and birefringence occurs. The higher the degree of orientation, the greater the birefringence. This film cannot be used in fields with polarizing effects because of the rainbow pattern caused by birefringence, which restricts the application of BOPET polyester film in liquid crystal display panels and polarizers.
[0003] At present, a lot of research has 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. In addition, this polyester film usually needs to be surface coated to have better optical properties and scratch resistance, so as to be used. Due to the structural characteristics of polyester PET itself, there are defects such as low surface energy and poor adhesion. Therefore, it is necessary to coat a bonding layer on the surface of the polyester film to increase the adhesion of the post-processing coating. In summary, how to provide an optical polyester film with excellent optical properties, light rainbow patterns, and can be used for post-processing coating has become a problem that technicians in this field need to solve. Utility Model Content
[0004] The technical problem to be solved by the utility model is to provide a pre-coated low-rainbow optical polyester film in view of the deficiencies in the prior art.
[0005] In order to solve the above technical problems, the utility model adopts the following technical scheme: a pre-coated low-rainbow optical polyester film, comprising a core layer, a first surface layer and a first bonding layer arranged in sequence on one side of the core layer, a second surface layer and a second bonding layer arranged in sequence on the other side of the core layer, the core layer is provided with scattering particles A, the first surface layer is provided with scattering particles B, the second surface layer is provided with scattering particles C, the first bonding layer is provided with nanoparticles D, and the second bonding layer is provided with nanoparticles E; the particle sizes of the scattering particles A, the scattering particles B and the scattering particles C are all larger than those of the nanoparticles D and the nanoparticles E.
[0006] Preferably, the particle size of the scattering particles A is 1 μm to 20 μm, the particle size of the scattering particles B is 0.5 μm to 5 μm, the particle size of the scattering particles C is 0.5 μm to 10 μm, the particle size of the nanoparticles D is 10 nm to 45 nm, and the particle size of the nanoparticles E is 10 nm to 45 nm.
[0007] Preferably, the thickness D1 of the core layer is 10 μm to 100 μm, the thickness D2 of the first surface layer is 2 μm to 40 μm, and the thickness D3 of the second surface layer is 3 μm to 60 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.
[0008] Preferably, the thickness of the first adhesive layer is 50 nm to 200 nm, and the thickness of the second adhesive layer is 100 nm to 500 nm.
[0009] Preferably, the total haze of the pre-coated low rainbow optical polyester film is 0.4% to 3%, and the internal haze is 0.1% to 2.5%.
[0010] Preferably, the pre-coated low-rainbow optical polyester film has a thickness of 20 μm to 200 μm.
[0011] Preferably, the scattering particles are organic silicon particles, inorganic silicon particles or organic PMMA particles; and the nanoparticles are nano-silicon dioxide or nano-aluminum oxide.
[0012] Preferably, the pre-coated low rainbow optical polyester film has a phase retardation of 1 nm to 900 nm.
[0013] Beneficial Effects
[0014] The utility model comprises a core layer, a first surface layer, a second surface layer, a first bonding layer and a second bonding layer. By adding scattering particles and nanoparticles of different particle sizes in each layer, the crystal orientation of the polyester chain segments in the polyester film during the biaxial stretching process is changed to form an irregular state. At the same time, light is reflected and refracted multiple times on the surface of the micron particles and the nanoparticles, thereby offsetting the double refraction phenomenon of the biaxially stretched polyester.
[0015] At the same time, the first adhesive layer and the second adhesive layer can be used for re-coating, and have good adhesion with the subsequent coating. The pre-coated low rainbow optical polyester film provided by the utility model has a lower phase delay and good optical properties. The adhesive layer can increase the adhesion of the re-coated coating, and there is no halo phenomenon under polarized light, and it can be used in the fields of polarizers, screen protection, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural diagram of the utility model.
[0017] The numbers in the figure represent: 1: core layer; 2: first surface layer; 3: second surface layer; 101: scattering particle A; 201: scattering particle B; 301: scattering particle C; 4, first bonding layer; 401: nanoparticle D; 5, second bonding layer; 501: nanoparticle E. 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 pre-coated low rainbow optical polyester film, comprising a core layer 1, a first surface layer 2, a second surface layer 3, a first bonding layer 4, and a second bonding layer 5. The core layer 1 is provided with scattering particles A 101, the first surface layer 2 is provided with scattering particles B 201, the second surface layer is provided with scattering particles C 301, the first bonding layer 4 is provided with nanoparticles D 401, and the second bonding layer 5 is provided with nanoparticles E 501. The present invention provides scattering particles in the core layer 1, the first surface layer 2, and the second surface layer 3. The main purpose of adding scattering particles is to change the crystal orientation of the polyester chain segments in the polyester film during the biaxial stretching process to form an irregular state. At the same time, light is reflected and refracted multiple times on the surface of the micron particles, which offsets the birefringence phenomenon of the biaxially stretched polyester and can achieve a lower phase delay.
[0020] The present invention preferably selects the particle size of the scattering particles so that the scattering particles are located inside the core layer 1, the first surface layer 2, and the second surface layer 3, and can be well evenly dispersed in the polyester film, so as to maximize the scattering refraction when light passes through. Preferably, the particle size of the scattering particle A 101 is 1 μm to 20 μm, the particle size of the scattering particle B 201 is 0.5 μm to 5 μm, and the particle size of the scattering particle C 301 is 0.5 μm to 10 μm.
[0021] The pre-coated low rainbow optical polyester film of the present invention comprises a core layer 1, a first surface layer 2 and a second surface layer 3. Since scattering particles are added to the core layer 1, the first surface layer 2 and the second surface layer 3, the adhesion between the three layers will be affected to a certain extent. The utility model increases the thickness of the core layer 1 and reduces the thickness of the first surface layer 2 and the second surface layer 3. The relationship between the thickness D1 of the core layer 1, the thickness D2 of the first surface layer 2 and the thickness D3 of the second surface layer 3 is D1=D2+D3, so that the stratification problem between the three layers can be solved. At the same time, by designing the thickness of the core layer 1, the first surface layer 2 and the second surface layer 3, and preferably the particle size of the scattering particles A 101, the scattering particles B 201 and the scattering particles C 301, most of the particles are located inside the polyester film, and when the light passes through the polyester and particles inside the film, refraction and scattering will occur, thereby generating internal haze. The internal haze reflects the deviation of light when the light passes through the film, and also reflects the main role of adding scattering particles A 101, scattering particles B 201 and scattering particles C 301 in the present invention. Preferably, the thickness D1 of the core layer 1 is 10 μm to 100 μm, the thickness D2 of the first surface layer 2 is 2 μm to 40 μm, and the thickness D3 of the second surface layer 3 is 3 μm to 60 μm.
[0022] The utility model is provided with a first adhesive layer 4 on one side of the first surface layer 2, and a second adhesive layer 5 on one side of the second surface layer 3. The first adhesive layer 4 is provided with nanoparticles D, and the second adhesive layer 5 is provided with nanoparticles E. The pre-coated low-rainbow optical polyester film of the utility model is only a base film, and the surface is not coated, so it cannot be applied in many fields. Usually, the industry needs to further process and set a layer of coating on the surface of the optical polyester film to achieve anti-scratch, anti-glare, anti-static and other effects. However, this coating has poor adhesion on the surface of the optical polyester film and cannot be used. The utility model increases the adhesion of the polyester film and the post-processing coating through the first adhesive layer and the second adhesive layer. The first adhesive layer is provided with nanoparticles D, and the second adhesive layer is provided with nanoparticles E. The main function of setting the nanoparticles is, on the one hand, to further increase the scattering and refraction of light passing through the film, and on the other hand, to form small protrusions on the surface of the film to facilitate the film rolling.
[0023] Preferably, the particle size of the nanoparticle D is 10 nm to 45 nm, and the particle size of the nanoparticle E is 10 nm to 45 nm. Preferably, the thickness of the first adhesive layer is 50 nm to 200 nm, and the thickness of the second adhesive layer is 100 nm to 500 nm.
[0024] The particle sizes of the scattering particles A 101 , B 201 and C 301 are all larger than those of the nanoparticles D 401 and E 501 .
[0025] Example
[0026] The utility model discloses a pre-coated low rainbow optical polyester film, comprising a core layer 1, a first surface layer 2, a second surface layer 3, a first bonding layer 4, and a second bonding layer 5; the core layer is formed by polyester chips (model FG604, company: Yizheng Chemical Fiber) and scattering particles A 101 (model: MX-2000, PMMA particles, company: Soken Chemical, particle size 20 μm), the first surface layer 2 is formed by polyester chips (model FG604, company: Yizheng Chemical Fiber) and scattering particles B 201 (model: KS-300, organic silicon particles, company: Korea ASP, particle size 3 μm), and the second surface layer 3 is formed by polyester chips (model FG604, company: Yizheng Chemical Fiber) and scattering particles C 301 (model: C809, inorganic silicon particles, company: Grace, particle size 9 μm). After the film is formed by biaxial stretching, the thickness of the core layer 1 is 60 μm, the thickness of the first surface layer 2 is 25 μm, and the thickness of the second surface layer 3 is 35 μm. The first adhesive layer 4 is formed by polyurethane (model: HUX-541, company: ADEKA) and nanoparticles D 401 (model: EAC-ST, company: Nissan Chemical, Japan, particle size 15 nm), and the second adhesive layer 5 is formed by polyurethane (model: HUX-541, company: ADEKA) and nanoparticles E 501 (model: MEK-AC-4130Y, company: Nissan Chemical, Japan, particle size 45 nm); the thickness of the first adhesive layer 4 is 90 nm, and the thickness of the second adhesive layer 5 is 200 nm. The first adhesive layer 4 and the second adhesive layer 5 are respectively coated on the first surface layer 2 and the second surface layer 3 by online coating, and then formed by oven thermal curing.
[0027] The pre-coated low-rainbow optical polyester film of the utility model has a thickness of 120 μm, a total haze of 3%, an internal haze of 2.1%, and a phase delay of 350 nm.
[0028] 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 pre-coated low rainbow optical polyester film, comprising a core layer, a first surface layer and a first adhesive layer arranged in sequence on one side of the core layer, and a second surface layer and a second adhesive layer arranged in sequence on the other side of the core layer, characterized in that: The core layer is provided with scattering particles A, the first surface layer is provided with scattering particles B, the second surface layer is provided with scattering particles C, the first bonding layer is provided with nanoparticles D, and the second bonding layer is provided with nanoparticles E; the particle sizes of the scattering particles A, the scattering particles B and the scattering particles C are all larger than those of the nanoparticles D and the nanoparticles E; The scattering particles A are PMMA particles; The scattering particles B are organic silicon particles; The scattering particles C are inorganic silicon particles; The nanoparticle D is nano-silicon dioxide or nano-aluminum oxide; The nanoparticles E are nano-silicon dioxide or nano-aluminum oxide.
2. A pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The particle size of the scattering particles A is 1 μm to 20 μm, the particle size of the scattering particles B is 0.5 μm to 5 μm, the particle size of the scattering particles C is 0.5 μm to 10 μm, the particle size of the nanoparticles D is 10 nm to 45 nm, and the particle size of the nanoparticles E is 10 nm to 45 nm.
3. The pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The thickness D1 of the core layer is 10 μm to 100 μm, the thickness D2 of the first surface layer is 2 μm to 40 μm, and the thickness D3 of the second surface layer is 3 μm to 60 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.
4. The pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The thickness of the first bonding layer is 50 nm to 200 nm, and the thickness of the second bonding layer is 100 nm to 500 nm.
5. The pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The total haze of the pre-coated low-rainbow optical polyester film is 0.4% to 3%, and the internal haze is 0.1% to 2.5%.
6. The pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The thickness of the pre-coated low-rainbow optical polyester film is 20 μm to 200 μm.
7. The pre-coated low rainbow optical polyester film according to claim 1, characterized in that: The pre-coated low rainbow optical polyester film has a phase retardation of 1 nm to 900 nm.