CN1760726A - Optical film and manufacturing method thereof - Google Patents

Abstract

The invention provides a method for manufacturing an optical film, which takes an olefin copolymerization transparent resin high molecular polymer which is easy to obtain and low in cost as a raw material, and dissolves the olefin copolymerization transparent resin high molecular polymer in a solvent in a dissolving way to form a solution for preparing a plastic film. By such a method for producing an optical film, an optical film having optical characteristics similar to those of the prior art can be obtained. Therefore, according to the present invention, when an optical film such as a protective film or a retardation film is produced, raw material acquisition becomes easy and cost reduction becomes possible.

Description

Optical film and manufacturing method thereof

technical field

The invention relates to an optical film, in particular to an optical film whose thickness can be reduced and a manufacturing method thereof.

Background technique

So far, some multifunctional films are pasted on the surface of the liquid crystal display (LCD), and these multifunctional functions can help the picture displayed on the LCD screen to be more optimized in terms of color and brightness. Therefore, these multifunctional films are indispensable accessories on LCD screens.

Generally speaking, these multifunctional films may include: anti-glare film, electromagnetic wave shielding layer, polarizer, transparent plastic plate (support material for polarizer), retardation plate, brightness enhancement film, etc.

Among them, the source of raw materials for some optical film layers is not easy to obtain, and the cost is also high. For example, a transparent plastic plate (such as TAC) used as a polarizer support is usually attached to both sides of the polarizer. This transparent plastic plate has high transparency, optical isotropy, no surface defects, heat resistance and moisture resistance. High hardness, low surface reflection loss, high hardness, good dimensional stability to temperature and humidity, and good processability. Therefore, when the transparent plastic plate is attached to both sides of the polarizer, it has a certain strength and has a certain protective effect against heat and humidity. It can not only support the polarizer, but also effectively protect the polarizer.

However, the supporting material of the polarizing plate must have the above characteristics in order to effectively support and protect the polarizing plate. Therefore, it is not easy to obtain the raw material source of the support material and the cost is high.

Taking the retardation film (extended polymer film) as an example, the retardation film must have high transparency, suitable optical anisotropy, no defects on the surface, high heat resistance and humidity resistance, low surface reflection loss and high hardness. The dimensional stability of temperature and humidity is good, and the processability is good, so as to effectively compensate the phase change of the liquid crystal cell (cell), and increase the viewing angle of the liquid crystal display screen.

Similarly, the retardation film must not only have the above-mentioned characteristics, but also need to have a suitable retardation value to effectively compensate the phase change of the liquid crystal cell, and the raw material source of the retardation film is difficult to obtain and the cost is high.

In addition, another kind of retardation film (LCP or LC), which is coated on the substrate by lamination of discotic liquid crystal or rod-shaped liquid crystal, this kind of retardation film has more precise optical compensation and higher contrast and viewing angle features. Therefore, this kind of retardation film is not only difficult to obtain raw material source and high cost, but also its process is more complicated.

In view of this, the present invention proposes a method for manufacturing an optical film, which can make the source of raw materials easy to obtain and low in cost.

Contents of the invention

The main purpose of the present invention is to provide a protective film with easy raw material source and low cost. To achieve this purpose, the present invention proposes a method for producing an optical film, which includes selecting a cycloolefin copolymerized transparent resin (COC) high molecular polymer as a raw material, providing a solvent that can dissolve the cycloolefin copolymerized transparent resin high molecular polymer, and using Cyclic olefin copolymerized transparent resin high molecular polymer is dissolved in a solvent to form a solution, and the solution is shaped to form a protective film and other steps.

In a preferred embodiment of the present invention, the solvent used in the above steps is, for example, a non-polar organic solvent such as toluene.

In a preferred embodiment of the present invention, the above method steps further include performing a stability test on the solution first, and then deciding whether to form a protective film on the solution, wherein, if the solution passes the stability test, then forming a protective film on the solution, The opposite is not true.

For the solution molding part, the solution can be injected through the die, or the solution can be applied on a flat surface with a scraper to form the solution into a protective film.

Moreover, this invention can manufacture the optical film of retardation film type other than a protective film type. This manufacturing method is to continue the above-mentioned manufacturing method, bake the protective film after shaping, heat the protective film after baking, and heat it to the glass transition temperature, and heat the protective film heated to the glass transition temperature. Stretching action to form retardation film and other steps.

Description of drawings

FIG. 1 is a flowchart of a method for manufacturing an optical film according to a preferred embodiment of the present invention.

Fig. 2 is a stability test table of a preferred embodiment of the present invention.

Fig. 3 is a stability test table of a preferred embodiment of the present invention.

FIG. 4 is a comparison table of characteristics of the retardation film molded from the blending solution of the preferred embodiment of the present invention and the retardation film of the prior art.

Description of figure number:

101～107: Steps

Detailed ways

In order to have a further cognition and understanding of the features, purposes and functions of the present invention, the detailed description is as follows in conjunction with the accompanying drawings:

In order to replace the prior art protective film raw materials, such as triacetate cellulose (TAC), and replace the retardation film raw materials, such as triacetate cellulose (TAC), cycloolefin polymer (COP) (Zeonor, Arton), the present invention is particularly based on Cyclic olefin copolymerized transparent resin (COC) macromolecular polymer replaces the above-mentioned raw materials. Firstly, discussing the acquisition of raw material sources and the cost of raw materials, this cycloolefin copolymerized transparent resin polymer is indeed easier to obtain and lower in cost than the prior art triacetate fiber and cycloolefin polymer (COP) sources.

Because this cycloolefin copolymerized transparent resin high molecular polymer was originally the base material of general optical discs or optical lenses. Therefore, when the present invention uses cycloolefin copolymerized transparent resin macromolecular polymer as the optical film raw material such as protective film, phase difference film, the technology that cycloolefin copolymerized transparent resin macromolecular polymer forms these optical films must be with cycloolefin copolymerization There are different processes for forming optical discs or optical lens substrates from transparent resin polymers.

The reason is that the process of forming optical discs or optical lens base materials by cyclic olefin copolymerization transparent resin polymers is to melt olefin copolymerization transparent resin polymers into optical disc discs or optical lens base materials. The method of melt molding can be, for example, a method of melt blending (melt blending), that is, firstly, two or more olefin copolymerized transparent resin polymers with different components are melted and blended, and then the blended melt Thermoplastic processing is performed to make optical discs or optical lens substrates. Or, elastomers, such as SBS, SEBS, SEPS, etc., can also be melt-blended with two or more olefin copolymerized transparent resin polymers of different components, and then the blended melt can be processed by thermoplastic processing. It can be formed into optical disc or optical lens substrate to increase the toughness of optical disc or optical lens substrate.

However, the above optical discs or optical lens substrates must undergo processes such as melt blending or thermoplastic processing in the process, so it is easy to cause the mixture of olefin copolymerized transparent resin high molecular polymer to be heated and deteriorate, such as yellowing. And if you want to add antioxidants and stabilizers in the process of melt blending or thermoplastic processing to maintain the stability of the mixture of olefin copolymerized transparent resin polymers, it may reduce the optical properties of the mixture of olefin copolymerized transparent resin polymers .

Therefore, the present invention proposes a method for manufacturing an optical film. Please refer to FIG. 1 , which is a flowchart of a method for manufacturing an optical film according to a preferred embodiment of the present invention. First, select the olefin copolymerized transparent resin (COC) high molecular polymer as the raw material, in which a single component of the olefin copolymerized transparent resin (COC) high molecular polymer or a variety of olefin copolymerized transparent resin high molecular polymers with different components can be used. Mixing, this is step 101. Next, a solvent capable of dissolving the olefin copolymerized transparent resin polymer is provided, and the commonly used organic solvent is, for example, toluene, methylene chloride or cyclohexane. And the olefin copolymerized transparent resin polymer selected in step 101 is dissolved in a solvent to form a solution, which is step 102 .

After the solution containing the olefin copolymerized transparent resin polymer is formed, the solution needs to be tested for stability to determine whether the solution is suitable for making an optical film, which is step 103 . And when the solution in step 103 is suitable for making an optical film, the solution can be made into an optical film, for example, by injection molding of a die, and in a preferred embodiment of the present invention, the solution is directly coated with a doctor blade Distributed on a flat surface to form an optical film, this is step 104 .

The optical film produced in step 104 can be used as a protective film such as a polarizer support. Moreover, the protective film can also be processed through subsequent processes to form a compensation film such as a retardation film.

Therefore, continue to bake the optical film produced in step 104 , which is step 105 . Next, the optical film is heated to the glass transition temperature (Tg), which is step 106 . Finally, stretching the optical film at the glass transition temperature can produce, for example, a retardation film, which is step 107 . Wherein, the condition of the stretching operation in step 107 will determine the value of the refractive index of the retardation film.

Please refer to FIG. 2 , which is a stability test table of a preferred embodiment of the present invention. It can be seen from Fig. 2 that the solutions of different components of olefin copolymerized transparent resin high molecular polymers dissolved in toluene include A, B, C, D and so on. Among them, the solutions of numbers A and B were stable even after about 144 hours. After 3 hours and 24 hours respectively, the toluene in the solutions numbered D and C became jelly-like due to high viscosity, which was unstable. Therefore, when performing a stability test on these solutions to determine whether to form a film, the solutions numbered B and A will be considered.

Please refer to FIG. 3 , which is a stability test table of a preferred embodiment of the present invention. In Fig. 3, the solutions numbered A, B, etc. in Fig. 2 are selected to be mixed in different proportions as the solution to be molded into a film. In this way, a better combination of thermal and mechanical properties can be obtained.

Please refer to FIG. 4 . FIG. 4 is a comparison table of characteristics of the retardation film molded from the mixed solution of the preferred embodiment of the present invention and the retardation film of the prior art. In Fig. 4, the retardation film made by the present invention with the number A (10%) solution-number B (90%) solution mixed solution is compared with the prior art retardation film (Zeonor), the retardation film of the present invention In terms of numerical performance such as light transmittance, it is close to the retardation film of the prior art.

Based on the above, the present invention proposes a method for manufacturing an optical film, which uses an olefin copolymerized transparent resin polymer that is relatively easy to obtain and has a low cost as a raw material, and dissolves the olefin copolymerized transparent resin polymer in a dissolving manner. in a solvent to form a solution ready to be molded into a film. Through such an optical film manufacturing method, an optical film with optical properties similar to those of the prior art can be obtained. Therefore, according to the present invention, when producing an optical film such as a protective film or a retardation film, the raw materials can be easily obtained and the cost can be reduced.

The above descriptions are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. That is, all equivalent changes and modifications made according to the claims of the present invention will still not lose the gist of the present invention, nor depart from the spirit and scope of the present invention, so all should be regarded as further implementation status of the present invention.

Claims (10)

1. A method for manufacturing an optical film, comprising the following steps: Select a cycloolefin copolymerized transparent resin (COC) polymer as a raw material; providing a solvent capable of dissolving the cycloolefin copolymerized transparent resin polymer, and dissolving the cycloolefin copolymerized transparent resin polymer in the solvent to form a solution; and This solution was shaped into a protective film. 2. The method for producing an optical film according to claim 1, wherein the solvent is an organic solvent. 3. The optical film manufacturing method according to claim 1, further comprising: Conduct a stability test on the solution first, and then decide whether to form the protective film on the solution, wherein, if the solution passes the stability test, then form the protective film on the solution, and vice versa. 4. The optical film manufacturing method according to claim 1, further comprising: Injecting the solution through a die to shape the solution into the protective film. 5. The optical film manufacturing method according to claim 1, further comprising: The solution is spread on a flat surface with a spatula to shape the solution into the protective film. 6. The optical film manufacturing method according to claim 1, further comprising: The shaped protective film is baked to facilitate the formation of a one-bit phase difference film. 7. The optical film manufacturing method according to claim 6, further comprising: The protective film after baking is heated to its glass transition temperature. 8. The optical film manufacturing method according to claim 7, further comprising: The protective film heated to the glass transition temperature is stretched to form the retardation film. 9. The manufacturing method of an optical film as claimed in claim 8, wherein the refractive index value of the retardation film is determined according to the stretching action under different conditions. 10. The optical film manufacturing method according to claim 1, further comprising: Several cycloolefin copolymerized transparent resin (COC) polymers were selected as raw materials with different proportions.

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