TWI621518B - A method for manufacturing retardation film by using dual-axial stretching process and a retardation film - Google Patents

Abstract

The invention relates to a method for manufacturing a retardation film by a two-axis synchronous stretching method, wherein a film of a polymethyl methacrylate (PMMA) material is simultaneously stretched to 1.0 to 5.0 times in a traveling direction and a wide direction, A large size film is obtained. Further, the annealing temperature parameter and the traveling direction and the width direction of the film are simultaneously retracted to control the decrease in refraction due to the extension stress. In order to further control the optical homogeneity of the film, the optical variation caused by the film surface temperature after the extension of the film is controlled to improve the optical properties of the film: R0: 0~3 nm (where R0=α△T _{extends) Temperature} + β △ X _{stretching ratio} + γ ΔT _{annealing temperature} + δ △ X _{retraction ratio} + C1), and Rth: 0 ~ -40 nm (where Rth = a ΔT _{extension temperature} + b △ X _{extension ratio} + c △ T _{annealing temperature} + d △ X _{retraction ratio} + C2).

Description

Method for manufacturing retardation film by biaxial synchronous extension method and retardation film thereof

The present invention relates to a manufacturing method for manufacturing a retardation film by a two-axis synchronous stretching method, and more particularly to fabricating a film having a large width and a high optical uniformity by simultaneously extending and retracting in a film traveling direction and a wide width direction. A method for producing a polymethyl methacrylate (PMMA) retardation film.

The retardation film is generally used on a display panel of a display device such as a liquid crystal display device (LCD) or an organic electroluminescence display device (OLED) to improve contrast, viewing angle, and high optical uniformity. A conventional material of a retardation film which is often used on a liquid crystal display panel is a cellulose triacetate film (TAC). The cellulose derivative has excellent moisture permeability and is advantageous for moisture transmission and volatilization of the polarizing plate. However, as the panel industry meets the more stringent high temperature and high humidity loop measurement specifications, due to the high water absorption rate of TAC, its dimensional stability and surface characteristics are susceptible to environmental influences. Therefore, the market trend is gradually polymethyl methacrylate (PMMA). Replace it.

Due to the special optical properties required for the retardation film, the commercially available polymethyl methacrylate (PMMA) cannot meet the specification requirements, and the copolymer needs to be modified by copolymerization. However, polymethyl methacrylate (PMMA) is not easily applied to the retardation film because its special polymeric segment and synthesis method are not easy and expensive. In general, one of the important issues in the manufacture of retardation films is mainly to control the birefringence of the retardation film. There are two common control methods for the birefringence of the retardation film: 1. Alignment birefringence: the difference in birefringence between the material itself caused by the difference in the forming orientation of the molten material at a temperature higher than the glass transition temperature. 2. Photoelastic birefringence: The change of volume after the material is subjected to stress causes the birefringence change in all directions, and the photoelastic coefficient of the material is often used as an observation index.

The typical polymethyl methacrylate photoelastic coefficient in the market is usually 6×10-12 Pa-1, and as long as there is a slight stress change, the refractive index changes, and it is difficult to stably control the birefringence. In the prior art, a common improvement is to copolymerize methyl methacrylate with other monomers (ex. MMA, 3FMA, BzMA) to reduce the photoelastic coefficient. However, as described above, the specific polymeric segment and synthesis of such copolymers are difficult and expensive, so in the prior art, polymethyl methacrylate is still not easily applied to the retardation film.

In view of the above, the main object of the present invention is to provide a method for manufacturing a retardation film by a two-axis synchronous stretching method, which is manufactured to have a certain width and width by simultaneously extending and retracting in the traveling direction and the wide direction of the film. Optically uniform polymethyl methacrylate (PMMA) retardation film without copolymer synthesis.

To achieve the above object, the present invention provides a method for producing a retardation film by a two-axis simultaneous stretching method, comprising the steps of: step (A): providing a cast film; and step (B): in a preheating process, Preheating the cast film at a predetermined preheating temperature; step (C): performing a biaxial simultaneous extension of the cast film at a predetermined extension temperature in an extension process a stretching process; wherein, in the extending process, the stretch film (MD) and the lateral stretch ratio (TD) of the cast film are stretched in the longitudinal direction by 1.0 to 5.0 times; and the step (D): In the annealing process, the cast film is annealed at a predetermined annealing temperature to cause the cast film to be retracted in both its longitudinal and lateral directions; and step (E): in a cooling process, in a cooling process The cast film is cooled at a predetermined cooling temperature, and an output retardation film is output.

In an embodiment, the predetermined preheating temperature is between 100 ° C and 200 ° C, and a preheating wind speed heated during preheating is between 5 m/s and 22 m/s; the predetermined extension temperature is At 120 ° C ~ 200 ° C, and an extension of the extended wind speed when the extension is between 5m / s ~ 16m / s, so that the film temperature in the extension process can be controlled between 120 ~ 170 Between °C; the scheduled The annealing temperature is between 80 ° C and 200 ° C, and an annealing wind speed provided during annealing is between 5 m / s and 22 m / s; the predetermined cooling temperature is between 25 ° C and 120 ° C, and when cooled A cooling wind speed is provided between 5 m/s and 16 m/s; in the annealing process, the shrinkage ratio of the cast film in both MD and TD is between 0 and 18%.

In one embodiment, the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) are in accordance with the following mathematical conditions: R0=α*ΔTe+β*ΔXe+ γ*ΔTs+δ*ΔXs+C1; wherein R0 is the in-plane phase difference value of the output retardation film, and the R0 value is between 0 and 3 nm; ΔTe is the temperature difference in the extension program And ΔTe=Text-Tg; ΔXe is the difference in draw ratio in the extension procedure, and ΔXe=MD-TD; ΔTs is the temperature difference in the annealing procedure, and ΔTs=Tshrink -Tg; ΔXs is the retraction ratio value of the cast film in the annealing process, and ΔXs = [(1-MDshrink)*(1-TDshrink)-1]; wherein the MDshrink is the cast film a shrinkage ratio in the longitudinal direction in the annealing process, and TDshrink is a shrinkage ratio of the cast film in the transverse direction in the annealing process; α, β, γ, δ, and C1 are machine parameters, Tg is a material parameter and will have different parameter values depending on the processing machine or different materials. Wherein, α = -0.0879, β = -6.24, γ = 0.011, δ = -12.8, Tg = 118, and C1 = 2.19.

In one embodiment, the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) are in accordance with the following mathematical conditions: Rth=a*ΔTe+b*ΔXe+ c*△Ts+d*△Xs+C2; wherein Rth is the phase difference value of the output retardation film in the thickness direction, and the Rth value is between 0 and -40 nm; ΔTe is the temperature in the extension program Difference, and ΔTe=Text-Tg; ΔXe is the difference in draw ratio in the extension procedure, and ΔXe=MD-TD; ΔTs is the temperature difference in the annealing procedure, and ΔTs =Tshrink-Tg; ΔXs is the retraction ratio value of the cast film in the annealing process, and ΔXs=[(1-MDshrink)*(1-TDshrink)-1]; wherein the MDshrink is the cast a shrinkage ratio of the material film in the longitudinal direction in the annealing process, and TDshrink is a shrinkage ratio of the cast film in the transverse direction in the annealing process; a, b, c, d, and C2 are machine stages The parameter, Tg is the material parameter, which will have different parameter values depending on the processing machine or different materials. Where a = 0.958, b = 2.5, c = 0.321, d = 12.1, Tg = 118, C2 = -39.4.

In one embodiment, the material of the cast film is polymethyl methacrylate (PMMA), and the thickness ranges from 250 um to 1200 um, and the width ranges from 500 to 980 um.

In one embodiment, the in-plane phase difference R0 of the output retardation film is between 0 and 3 nm, and the phase difference Rth of the output retardation film in the thickness direction is between 0 and 40 nm. The refractive index value Nx of the in-plane slow axis direction is between 1.499900 and 1.499995, and the refractive index value Ny of the in-plane fast axis direction of the cast film is between 1.499900 and 1.499955, and the refractive index of the cast film in the thickness direction The value of the Nz system is between 1.0000 and 1.50004, and the thickness of the output retardation film ranges from 38 um to 250 um.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims .

31~36‧‧‧Steps

11‧‧‧T-die 11

12‧‧‧Cooling wheel

13‧‧‧ cast film

14‧‧‧Electrical field system

15‧‧‧Clamping wheel

16‧‧‧Hot machine

17‧‧‧Exporting

2a‧‧‧Extension machine track

2b‧‧‧Preheating section

2c‧‧‧Extension

2d‧‧‧annealing section

2e‧‧‧cooling section

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing an embodiment of a manufacturing method for manufacturing a retardation film by a two-axis synchronous stretching method according to the present invention.

Fig. 2 is a schematic view showing an embodiment of a die casting machine which is suitable for use in the production method of the present invention for manufacturing a retardation film by a two-axis simultaneous stretching method.

Fig. 3 is a schematic view showing an embodiment of a two-axis synchronous stretching machine which is suitable for the manufacturing method of manufacturing a retardation film by the two-axis synchronous stretching method of the present invention.

Referring to FIG. 1 to FIG. 3 , FIG. 1 is a flow chart of an embodiment of a manufacturing method for manufacturing a retardation film by a biaxial synchronous extension method according to the present invention; and FIG. 2 is applicable to the invention for manufacturing a phase by a two-axis synchronous extension method. A schematic view of an embodiment of a die casting machine for manufacturing a differential film; and FIG. 3 is a schematic view of an embodiment of a two-axis synchronous stretching machine suitable for the manufacturing method of the retardation film produced by the present invention in a two-axis synchronous stretching manner. As shown in FIG. 1, in an embodiment of the manufacturing method for manufacturing a retardation film in the biaxial synchronous extension mode of the present invention, the following steps are included: Step 31: A film of a cast material is provided. The raw material of polymethyl methacrylate (PMMA) was die-cast into a cast film used for the subsequent steps of this example by a die casting machine shown in Fig. 2. In this embodiment, the material of the cast film is polymethyl methacrylate (PMMA), and the thickness thereof ranges from 250 um to 1200 um, the width ranges from 500 to 980 um, and the photoelastic coefficient is usually 6×10 ^{− 12} Pa ^-1 . The specific details of this step 31 will be detailed later in the related description of FIG.

Step 32: Preheating. In a preheating procedure, the cast film is preheated at a predetermined preheat temperature. In this embodiment, the predetermined preheating temperature is in the range of 100 ° C to 200 ° C, and a preheating wind speed heated during preheating is in the range of 5 m / s to 22 m / s. In other words, in this preheating process, hot air blowing between 100 ° C and 200 ° C is supplied to the cast film at a preheating wind speed of between 5 m/s and 22 m/s. In a further preferred embodiment of the invention, the predetermined preheating temperature range is between 145 °C and 155 °C.

Step 33: Two-axis synchronous extension. In an extending process, a stretching process of the biaxially extending stretch of the cast film is performed at a predetermined extension temperature; wherein, in the extending process, the cast film is stretched in the longitudinal stretch ratio Both the (MD) and the lateral extension ratio (TD) are between 1.0 and 5.0 times. In this embodiment, the predetermined extension temperature is in the range of 120 ° C to 200 ° C, and an extended wind speed heated when extending is in the range of 5 m / s to 16 m / s. In other words, in this extension procedure, hot air flowing between 120 ° C and 200 ° C is supplied to the cast film at a heating wind speed of between 5 m/s and 16 m/s, so that the cast film is The film temperature at the time of the extension process (i.e., the temperature of the cast film itself) can be controlled to be in the range of 120 to 170 °C. In a more preferred embodiment of the invention, the predetermined extension temperature range is between 130 ° C and 150 ° C.

Step 34: Annealing is performed. In an annealing process, the cast film is annealed at a predetermined annealing temperature such that the cast film is simultaneously retracted in both its longitudinal and transverse directions. In this embodiment, the predetermined annealing temperature is in the range of 80 ° C to 200 ° C, and an annealing wind speed provided during annealing is in the range of 5 m / s to 22 m / s. In other words, in this annealing process, hot air blowing between 80 ° C and 200 ° C is supplied to the cast film at an annealing wind speed of between 5 m/s and 22 m/s. Moreover, in the annealing process, the shrinkage ratio of the cast film in both the longitudinal direction (ie, the direction of the MD) and the transverse direction (ie, the direction of the TD) is between 0 and 18%. In a more preferred embodiment of the invention, the predetermined annealing temperature ranges from 120 ° C to 150 ° C.

Step 35: Perform cooling. In a cooling process, the cast film is cooled at a predetermined cooling temperature and an output retardation film is output (step 36). In this embodiment, the predetermined cooling temperature is in the range of 25 ° C to 120 ° C, and is provided when it is cooled. The cooling wind speed is in the range of 5 m/s to 16 m/s. In other words, in this cooling process, hot air blowing between 25 ° C and 120 ° C is supplied to the cast film at a cooling wind speed of between 5 m/s and 16 m/s. In a more preferred embodiment of the invention, the predetermined cooling temperature range is between 25 ° C and 100 ° C.

In the present invention, the output retardation film produced by the respective processes of preheating, biaxial stretching, annealing, and cooling through the specific temperature and wind speed ranges described above has an in-plane phase difference value R0 of 0~. 3 nm, the phase difference Rth of the output retardation film in the thickness direction is between 0 and -40 nm, and the refractive index value Nx of the in-plane slow axis direction of the output retardation film is between 1.499900 and 1.499995, and the output phase difference is The refractive index value Ny of the in-plane fast axis direction of the film is between 1.499900 and 1.499955, and the refractive index value Nz of the output retardation film in the thickness direction is between 1.0000 and 1.50004, and the thickness of the output retardation film is between 38um~250um, and also has the characteristics of large width and high optical uniformity. Such optical characteristics can meet the needs of the industry for retardation films used on LCD or OLED display panels, and do not require copolymer synthesis at all, so the process is relatively simple and cost-effective.

In a preferred embodiment of the method for fabricating a retardation film in the biaxial synchronous extension mode of the present invention, in addition to the specific temperature and wind speed ranges described above, preheating, biaxial stretching, annealing, and cooling are performed. In addition, the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) must also meet the following mathematical conditions: R0=α*△Te+β*△Xe+γ*ΔTs+δ*ΔXs+C1; wherein R0 is the in-plane phase difference value of the output retardation film, and the R0 value is between 0 and 3 nm; ΔTe is the temperature difference in the extension procedure, and ΔTe=Text-Tg; ΔXe is the difference in draw ratio in the extension procedure, and ΔXe=MD-TD; ΔTs is in the anneal The temperature difference in the program, and ΔTs=Tshrink-Tg; ΔXs is the retraction ratio value of the cast film in the annealing procedure, and ΔXs=[(1-MDshrink)*(1-TDshrink)- 1]; wherein the MDshrink is a shrinkage ratio of the cast film in the longitudinal direction in the annealing process, and TDshrink is a shrinkage ratio of the cast film in the transverse direction in the annealing process; α, β , γ, δ and C1 are machine parameters, Tg is material parameters, according to different The processing machine or different materials will have different parameter values. In the present example, α = -0.0879, β = -6.24, γ = 0.011, δ = -12.8, Tg = 118, and C1 = 2.19.

In the preferred embodiment, the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) also meet the following mathematical conditions: Rth=a*ΔTe+b*△ Xe+c*△Ts+d*△Xs+C2; wherein Rth is the phase difference of the output retardation film in the thickness direction, and the Rth value is between 0 and -40 nm; ΔTe is in the extension program Temperature difference, and ΔTe=Text-Tg; ΔXe is the difference in draw ratio in the extension procedure, and ΔXe=MD-TD; ΔTs is the temperature difference in the annealing procedure, and ΔTs=Tshrink-Tg; ΔXs is a retraction ratio value of the cast film in the annealing process, and ΔXs=[(1-MDshrink)*(1-TDshrink)-1]; wherein the MDshrink is a shrinkage ratio of the cast film in the longitudinal direction in the annealing process, and TDshrink is a shrinkage ratio of the cast film in the transverse direction in the annealing process; a, b, c, d, and C2 are Machine parameters, Tg is the material parameters, according to different processing machines or different materials will have different parameter values. In the present embodiment, a=0.958, b=2.5, c=0.321, d=12.1, Tg=118, C2=-39.4.

As shown in Fig. 2, a schematic view of an embodiment of a die casting machine suitable for the production method of the retardation film produced by the biaxial synchronous stretching method of the present invention is shown. In order to provide a cast film for the two-axis simultaneous extension process, the granular polymethyl methacrylate (PMMA) resin material is firstly passed through a heat exchanger 16 (Adaptor) at 220 ° C to 270 ° C. The temperature between the resin esters was melted and kneaded and extruded into a T-die 11 (T-die). Next, the molten raw material is discharged from the discharge port 17 (Lip) by the T-die 11 and continuously applied to a cooling speed of 2 to 10 m/min (preferably about 5 m/min) and cooling in continuous rolling. On the roller 12 (Chill roller), the temperature near the discharge port 17 is 200 ° C to 250 ° C. At the same time, an electric field is applied by an electric field system 14 (Pinning wire) to allow the discharged raw material to be attached to the cooling roller 12 and thus cooled to form a film. The film is self-cooled by a cooling roller 12 and a roll off roller of a speed of 2 to 6.5 m/min (preferably about 4 to 6 m/min). The surface of the roller 12 is detached and becomes the cast film 13 of the present invention, and the thickness range thereof is between 250um~1200um, wide range from 500~980um, and continuous extending in the length direction. In the present embodiment, the composition ratio of the resin material is mainly composed of polymethyl methacrylate (code T11), the main layer structure is T11, and AS04-5 antistatic agent is added; The structure was T11 and MB30-1 anti-adhesion agent was added. Further, the speed difference between the cooling roller 12 and the pinch wheel 15 is controlled to be between ±1, and the optical axis and the phase difference are not affected, and the optical characteristics of the cast film 13 can be effectively controlled.

The cast film 13 which is sent out from the die casting machine shown in Fig. 2 and which is continuously extended in the longitudinal direction is fed into a two-axis synchronous stretching machine as shown in Fig. 3 to carry out the invention as described above. Step 32 to step 36. In the extension machine, each section can independently control its temperature and wind speed (the wind speed is controlled by the fan adjustment ratio). As shown in FIG. 3, under the clamping and guiding of the extension rail 2a, the casting film is subjected to the preheating process as described in the foregoing step 32 in the preheating section 2b of the stretching machine; at this time, the stretching machine does not The cast film is stretched in the width direction (ie, the transverse direction or the TD direction) or the length direction (ie, the longitudinal direction or the MD direction), but only with a preheating wind speed of between 5 m/s and 22 m/s. The hot air between 120 ° C and 200 ° C is supplied to the cast film to increase the film temperature of the cast film to a temperature suitable for the elongation process. Then, in the extension 2c of the extension machine, in addition to continuing to provide a hot air between 120 ° C and 200 ° C with a heating wind speed of between 5 m / s and 16 m / s, the wind is blown outside the cast film, and The cast film is stretched in the longitudinal direction (MD direction) and the transverse direction (TD direction) by the extension machine rail 2a, and the cast film is stretched in the extension process of the extension 2c. The stretch ratio (MD) and the lateral stretch ratio (TD) in the longitudinal direction are both 1.0 to 5.0 times. Next, in the annealing section 2d of the stretching machine, hot air blowing between 80 ° C and 200 ° C is supplied to the casting film at an annealing wind speed of between 5 m/s and 22 m/s to cast the casting material. The film is subjected to an annealing process; at the same time, the film of the cast material is synchronously guided in the longitudinal direction (MD direction) and the transverse direction (TD direction) by the extension machine rail 2a to be appropriately retracted, and the cast film is in the longitudinal direction thereof. The shrinkage ratio between the direction of the MD (the direction of the MD) and the lateral direction (ie, the direction of the TD) is between 0 and 18%. Thereafter, in the cooling section 2e of the stretching machine, hot air blowing between 25 ° C and 120 ° C is supplied to the casting material film at a cooling wind speed of between 5 m/s and 16 m/s, and the casting material is blown to the casting material. The film is cooled, and finally the output retardation film is output.

The following is a manufacturing method for manufacturing a retardation film by a two-axis synchronous stretching method according to the present invention. The above-mentioned process conditions and mathematical conditions are specifically verified by various test conditions, and the results of the verification confirm that the present invention Two-axis synchronous extension method to create phase difference The film manufacturing method can indeed produce the optical property requirements required by the industry for the retardation film used on an LCD or OLED display panel, and does not require copolymer synthesis at all.

First, in the process of the cast film according to the present invention as shown in Fig. 2, the composition ratio of the resin raw materials used in each of Examples 1 to 5 is shown in Table 1 below.

Next, in the process of the cast film according to the present invention as shown in FIG. 2, the speed of the pinch wheel is controlled and changed in different embodiments 1 to 5 (that is, the speed of the cooling roller and the pinch wheel is changed). The difference is the parameter value, and the optical axis value and the average phase difference of the obtained cast film are measured, and the results are shown in Table 2 below. It can be seen from Table 2 that the optical characteristics of the embodiments 1 to 4 are all in compliance with the requirements, and only the R0 value of the embodiment 5 does not meet the requirements. It can be proved that the speed difference between the cooling roller and the clamping wheel is controlled to be between ±1 (the clamping wheel speed is between 4 and 6 m/min), and the optical axis and the phase difference have no influence. It can effectively control the optical properties of the cast film.

Next, the cast film of Example 4 was taken, and in the process of manufacturing a retardation film in a biaxial synchronous extension manner according to the present invention as shown in FIG. 3, the elongation temperature was controlled and changed in different Examples 6 to 15. The film travel direction magnification MD, the width direction magnification TD, the annealing temperature, the film direction retraction ratio, the width direction retraction ratio, and the like, and the phase difference value (R0 and Rth) of the obtained output retardation film is detected. ), the results are shown in Table 3 below.

Since Table 3 includes changes in the stretching temperature, the film traveling direction magnification MD, the wide direction magnification TD, the annealing temperature, the film traveling direction retraction ratio, and the wide direction retraction ratio, it is not easy to directly from the table. In the third, the degree of influence of each parameter condition on the phase difference value of the output retardation film is seen. Therefore, by taking a few specific parameter condition fields and obtaining a simplified table with fewer fields, it is easier and clear to evaluate the degree of influence of each parameter condition on the phase difference of the output phase difference film (ie, contribution). degree). For example, if only the fields of number, extension temperature, extended wind speed, thickness, and phase difference are captured and organized into the following Table 4, it can be easily found by the data in Table 4, and the output of the phase difference film is The contribution values of the phase difference values R0 and Rth are respectively in accordance with the following mathematical formula: R0 = α ΔT _{extension temperature} ; Rth = a ΔT _{extension temperature} .

That is, R0 = α (extension temperature - Tg). Among them, Tg = 118, α = -0.0879. Also, Rth = a (extension temperature - Tg). Where Tg = 118 and a = 0.958. Among them, the Tg value in the machine parameters (material parameters) is actually different from the material of the cast film, not according to the machine; for example, polymethyl methacrylate (PMMA) code T11 In other words, the Tg value in the machine parameter (material parameter) is a fixed value or 118.

For example, if only the fields of the number, film traveling direction magnification, width direction magnification, thickness, and phase difference are captured and arranged into the following Table 5, the data can be easily found by the data in Table 5, and the output phase is The contribution values of the phase difference values R0 and Rth of the difference film are respectively in accordance with the following mathematical formula: R0 = β ΔX _{stretching ratio} ; Rth = b ΔX _{stretching ratio} .

That is, R0 = β (MD magnification - TD magnification), β = -6.24. Rth = b (MD magnification - TD magnification), b = 2.5.

For example, if only the fields of numbering, annealing temperature, annealing speed, thickness, and phase difference are taken and sorted into the following Table 6, the data of Table 6 can be easily found and the phase of the phase difference film is output. The contribution values of the differences R0 and Rth are respectively in accordance with the following mathematical formula: R0 = γ ΔT _{annealing temperature} ; Rth = c ΔT _{annealing temperature} .

That is, R0 = γ (annealing temperature - Tg), γ = 0.011. Rth = c (annealing temperature - Tg), c = 0.321.

For example, if only the number of the film, the retraction ratio of the film traveling direction, the retraction ratio in the width direction, the thickness, and the phase difference are captured, and the following table 7 is arranged, the data of Table 7 can be easily obtained. It is found that the contribution values of the phase difference values R0 and Rth of the output retardation film are respectively in accordance with the following mathematical formula: R0= _{δΔX retraction ratio} ; Rth= _{dΔX retraction ratio} .

That is, R0=δ[(1-MD retraction ratio)*(1-TD retraction ratio)-1], δ = -12.8. Rth=d[(1-MD retraction ratio)*(1-TD retraction ratio)-1], d=12.1.

Therefore, after synthesizing the mathematical conditional expressions verified as shown in Tables 4 to 7, the two mathematical conditional expressions of the present invention as described above can be obtained, and if the data substituted in Table 3 is also verified: R0=α*ΔTe+β* ΔXe+γ*ΔTs+δ*ΔXs+C1; and Rth=a*ΔTe+b*ΔXe+c*ΔTs+d*ΔXs+C2.

Since the details of the two mathematical conditional expressions have been described in detail above, they will not be described again here. If the method of the present invention is to be implemented on another different machine equipment, the conditions with different known parameters (ie, controlling and changing the extension temperature, the film traveling direction magnification MD, and width) may be first provided in a manner similar to Table 3. Amplitude direction magnification TD, annealing temperature, film traveling direction retraction a plurality of different embodiments of the parameter conditions such as the ratio, the width direction retraction ratio, and the like, and the phase difference values R0 and Rth of the output retardation film manufactured according to the embodiments are measured by an instrument, and then these After knowing the parameter conditions and substituting the above two mathematical conditional formulas, the machine parameters such as α, β, γ, δ, C1, a, b, c, d, and C2 can be calculated. After that, we can re-adjust and plan the most appropriate extension temperature, film travel direction magnification MD, width direction magnification TD, annealing temperature, film travel direction based on these two mathematical conditions and the obtained machine parameter values. Parameter conditions such as retraction ratio and wide-direction retraction ratio, and mass production of phase difference film products meeting the requirements of optical characteristics in the industry. Therefore, according to the process steps shown in FIG. 1 according to the present invention, the specific temperature, wind speed, extension ratio and shrinkage ratio parameter conditions, and the two mathematical conditional formulas as described above, can be made of PMMA as raw materials. The phase difference film product used for the optical requirement of the retardation film on the LCD or OLED display panel, and the copolymer synthesis is not required at all, and can be implemented according to the contents of the present invention and achieve the claimed effect of the present invention.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents of the present invention are intended to be included within the scope of the present invention.

Claims (9)

A manufacturing method for manufacturing a retardation film by a two-axis synchronous stretching method, comprising the steps of: step (A): providing a cast film; and step (B): in a preheating process at a predetermined preheating temperature Preheating the cast film; step (C): performing a biaxial simultaneous stretching process on the cast film at a predetermined extension temperature in an extension process; wherein, in the extension In the program, the cast film is stretched in the longitudinal direction (MD) and the lateral stretch ratio (TD) are both 1.0 to 5.0 times; step (D): in an annealing process, at a predetermined Annealing the film of the cast material at an annealing temperature such that the cast film is simultaneously retracted in both its longitudinal and transverse directions; and step (E): in a cooling process, at a predetermined cooling temperature The cast film is cooled and outputs an output retardation film; wherein the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) meet the following mathematical conditions; R0= α*△Te+β*△Xe+γ*△Ts+δ*△Xs+C1; where R0 is the input The in-plane phase difference of the retardation film, and the R0 value is between 0 and 3 nm; ΔTe is the temperature difference in the extension program, and ΔTe=Text-Tg; ΔXe is in the extension program The draw ratio difference, and ΔXe=MD-TD; ΔTs is the temperature difference in the annealing process, and ΔTs=Tshrink-Tg; ΔXs is the retraction of the cast film in the annealing process a ratio value, and ΔXs=[(1-MDshrink)*(1-TDshrink)-1]; wherein the MDshrink is a shrinkage ratio of the cast film in the longitudinal direction in the annealing process, and TDshrink is the The shrinkage ratio of the cast film in the transverse direction in the annealing process; α, β, γ, δ, and C1 are machine parameters, and Tg is a material parameter. The method for manufacturing a retardation film according to claim 1, wherein the predetermined preheating temperature is between 100 ° C and 200 ° C, and a preheating wind speed heated during preheating is between 5 m / s~22m/s; the predetermined extension temperature is between 120 ° C and 200 ° C, and an extended wind speed that is heated when extended is Between 5m/s and 16m/s, the film temperature of the cast film during the extension process can be controlled between 120 and 170 ° C; the predetermined annealing temperature is between 80 ° C and 200 ° C. And an annealing wind speed provided during annealing is between 5 m/s and 22 m/s; the predetermined cooling temperature is between 25 ° C and 120 ° C, and a cooling wind speed provided during cooling is between 5 m /s~16m/s; in the annealing process, the shrinkage ratio of the cast film in both MD and TD is between 0 and 18%. The method for producing a retardation film according to claim 2, wherein α = -0.0879, β = -6.24, γ = 0.011, δ = -12.8, Tg = 118, and C1 = 2.19. The method for producing a retardation film according to claim 1, wherein the predetermined extension temperature (Text), the MD value, the TD value, and the predetermined annealing temperature (Tshrink) satisfy the following mathematical conditions :Rth=a*△Te+b*△Xe+c*△Ts+d*△Xs+C2; wherein Rth is the phase difference of the output phase difference film in the thickness direction, and the Rth value is between 0~ -40 nm; ΔTe is the temperature difference in the extension procedure, and ΔTe=Text-Tg; ΔXe is the difference in draw ratio in the extension procedure, and ΔXe=MD-TD; ΔTs is The temperature difference in the annealing procedure, and ΔTs=Tshrink-Tg; ΔXs is the retraction ratio value of the cast film in the annealing procedure, and ΔXs=[(1-MDshrink)*(1- TDshrink)-1]; wherein the MDshrink is a shrinkage ratio of the cast film in the longitudinal direction in the annealing process, and TDshrink is a shrinkage ratio of the cast film in the transverse direction in the annealing process; a, b, c, d, and C2 are machine parameters, and Tg is a material parameter. The method for producing a retardation film according to the fourth aspect of the invention, wherein a=0.958, b=2.5, c=0.321, d=12.1, Tg=118, C2=-39.4. The method for manufacturing a retardation film according to claim 2, wherein the predetermined preheating temperature range is between 145 ° C and 155 ° C; the predetermined extension temperature range is between 130 ° C and 150 ° C; The predetermined annealing temperature range is between 120 ° C and 150 ° C; The predetermined cooling temperature range is between 25 ° C and 100 ° C. The method for producing a retardation film according to the first aspect of the invention, wherein the material of the cast film is polymethyl methacrylate (PMMA), and the thickness ranges from 250 um to 1200 um, and the width range is between 500~980um. The method of manufacturing a retardation film according to the first aspect of the invention, wherein the in-plane phase difference R0 of the output retardation film is between 0 and 3 nm, and the phase difference of the output retardation film in the thickness direction is The Rth system is between 0 and 40 nm, and the refractive index value Nx of the in-plane slow axis direction of the cast film is between 1.499900 and 1.499995, and the refractive index value Ny of the in-plane fast axis direction of the cast film is 1.499900. ~1.499955, the refractive index value Nz of the thickness direction of the cast film is between 1.0000 and 1.50004, and the thickness of the output retardation film ranges from 38 um to 250 um. A retardation film produced by the manufacturing method according to the first aspect of the invention, wherein the in-plane retardation value R0 of the retardation film is between 0 and 3 nm, and the phase difference Rth in the thickness direction is Between 0 and -40 nm, the thickness ranges from 38 um to 250 um; and the thickness of the cast film ranges from 250 um to 1200 um, and the width ranges from 500 to 980 um, and the in-plane slow axis direction of the cast film The refractive index value Nx is between 1.499900 and 1.499995, and the refractive index value Ny of the in-plane fast axis direction of the cast film is between 1.499900 and 1.499955, and the refractive index value Nz of the thickness of the cast film is 1.00001. ~1.500045.