Cycloolefin polymer, preparation method thereof and optical film

Abstract

The invention provides a cycloolefin polymer, a preparation method thereof and an optical film. In the structure of the cycloolefin polymer, at least part of repetitive units contain substituent groups, and the substituent groups are selected from any one of methyl, ethyl, isopropyl, tert-butyl and phenyl. According to the present invention, the cycloolefin polymer structure has the substituent group, such that the space is not easily stacked, and the crystallization trend can be effectively eliminated so as to avoid the turbidity of the formed cycloolefin polymer during the hydrogenation process due to the crystallization, and improve the optical performance of the prepared optical film.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optical film manufacturing, and particularly relates to a cyclic olefin polymer and a preparation method and an optical film thereof. BACKGROUND

[0002] COP (Cyclic Olefin Polymer) is a material obtained by hydrogenating all unsaturated bonds on a polymer after ring-opening metathesis polymerization of a cyclic olefin. COP has a series of excellent properties such as high heat distortion temperature, high transparency, low birefringence and small dielectric loss, and is an important material for preparing various optical elements.

[0003] COP can be generally obtained by polymerization of monomers such as norbornene, and has a glass transition temperature between 90 DEG C and 150 DEG C. However, existing COPs are prone to turbidity or even gelation during hydrogenation, resulting in low transparency and poor optical performance of the final optical film.

[0004] Therefore, how to develop a COP that is not prone to turbidity and can maintain a high glass transition temperature, thereby improving the optical performance and thermal performance of the optical film, is a problem to be solved at present. SUMMARY

[0005] The application provides a cyclic olefin polymer and a preparation method and an optical film thereof, and aims to solve the problem that existing cyclic olefin polymers in the field of optical film manufacturing cannot simultaneously have good glass transition temperature and optical performance.

[0006] The first embodiment of the application provides a cyclic olefin polymer, which comprises repeating unit I and repeating unit II, and the structural formula of the repeating unit is shown as formula I:

[0007]

[0008] The structural formula of the repeating unit II is shown as formula II:

[0009]

[0010] wherein R is selected from any one of methyl, ethyl, isopropyl, tert-butyl and phenyl;

[0011] n = 0-10;

[0012] p = 1-100000;

[0013] q = 1-100000.

[0014] In some embodiments, the structure of the cyclic olefin polymer is shown as formula III:

[0015]

[0016] n = 0 to 10;

[0017] p = 1 to 100000;

[0018] q = 1 to 100000.

[0019] In some embodiments, the molar ratio of repeating unit I to repeating unit II is 1–9:9–1.

[0020] In some embodiments, the cyclic olefin polymer has a weight-average molecular weight of 5,000 to 150,000 and a molecular weight distribution of 1.2 to 6.0.

[0021] In some embodiments, the glass transition temperature of the cyclic olefin polymer is 100–155°C.

[0022] In some embodiments, the melt index of the cyclic olefin polymer is 5 to 30 g / 10 min (280 degrees Celsius, 2160 g pressure).

[0023] The second embodiment of this application provides a method for preparing a cyclic olefin polymer, which is used to prepare the cyclic olefin polymer in any of the above embodiments, and includes the following steps:

[0024] A first monomer and a second monomer are provided and mixed with 1-hexene to carry out the first step reaction, resulting in a reaction solution containing intermediate products.

[0025] The intermediate product was extracted and precipitated, a catalyst was added, and the reaction was carried out under heat and pressure to obtain the cyclic olefin polymer.

[0026] Wherein, at least one of the first monomer and the second monomer is an amorphous monomer.

[0027] In some embodiments, the first monomer is selected from any one of R1-substituted norbornene, tetracyclododecene, and hexacycloheptadecene, wherein the R1 group is selected from any one of methyl, ethyl, isopropyl, tert-butyl, and phenyl.

[0028] The second monomer is selected from tetracyclododecene or hexacycloheptadecene.

[0029] In some embodiments, the mass ratio of 1-hexene to the sum of the masses of the first monomer and the second monomer is 0.5 to 1.5:100.

[0030] In some embodiments, the catalyst is selected from at least one of molybdenum pentachloride, tungsten hexachloride, and titanium tetrachloride.

[0031] In some embodiments, the second monomer is tetracyclododecene, and the molar ratio of the first monomer to the second monomer is 1-9:9-1.

[0032] In some embodiments, the second monomer is hexacycloheptadecene, and the molar ratio of the first monomer to the second monomer is 2-8:8-2.

[0033] In some embodiments, the step of providing the first monomer and the second monomer further includes:

[0034] A third monomer is provided, which is mixed with the first monomer and the second monomer;

[0035] The third monomer includes tetracyclododecene or hexacycloheptadecene, and the third monomer is different from the first monomer and the second monomer, respectively.

[0036] In some embodiments, the molar ratio of the first monomer, the second monomer, and the third monomer is 1–2:3–5:3–5.

[0037] In some embodiments, the temperature of the second step reaction is 140–190°C.

[0038] In some embodiments, the pressure of the second step reaction is 4 to 8 MPa.

[0039] The third embodiment of this application provides an optical film made of the cyclic olefin polymer in any of the above embodiments.

[0040] In some embodiments, the optical film has an in-plane retardation Re, a thickness d, and a thickness direction retardation Rth, satisfying:

[0041] 0.0001≤Re / d≤0.00025;

[0042] And Rth / d≤0.0025.

[0043] In some embodiments, Re ≤ 5 nm.

[0044] In some embodiments, 0 ≤ Rth ≤ 50 nm.

[0045] In some embodiments, 20μm≤d≤60μm.

[0046] This application provides a cyclic olefin polymer, wherein at least some of the repeating units contain substituents selected from methyl, ethyl, isopropyl, tert-butyl, and phenyl. Because the cyclic olefin polymer provided in this application contains substituents, spatial stacking is less likely, effectively eliminating the tendency for crystallization. This prevents the formed cyclic olefin polymer from becoming cloudy during hydrogenation due to crystallization, thereby improving the optical performance of the prepared optical film. Attached Figure Description

[0047] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0048] Figure 1 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 1 of this application;

[0049] Figure 2 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 2 of this application;

[0050] Figure 3 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 3 of this application;

[0051] Figure 4 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 4 of this application;

[0052] Figure 5 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 5 of this application;

[0053] Figure 6 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 6 of this application;

[0054] Figure 7 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 7 of this application;

[0055] Figure 8 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 8 of this application;

[0056] Figure 9 Infrared absorption spectrum of a cyclic olefin polymer provided in Example 9 of this application;

[0057] Figure 10 Infrared absorption spectrum of a cyclic olefin polymer provided in Example 10 of this application;

[0058] Figure 11 Infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 1 of this application;

[0059] Figure 12 Infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 2 of this application;

[0060] Figure 13 The infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 3 of this application is shown. Detailed Implementation

[0061] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0062] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0063] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure of this application, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit this application.

[0064] The first embodiment of this application provides a cyclic olefin polymer, including repeating unit I and repeating unit II, the structural formula of which is shown in Formula I:

[0065]

[0066] The structural formula of repeating unit II is shown in Equation II:

[0067]

[0068] Wherein, R is selected from any one of methyl, ethyl, isopropyl, tert-butyl, and phenyl;

[0069] n = 0 to 10, which means that the value of n can be any value among 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;

[0070] p = 1 to 100000. It can be understood that the value of p can be any value among 1, 10, 100, 10000, 100000 or any range between two values.

[0071] q = 1 to 100000. It can be understood that the value of q can be any value among 1, 10, 100, 10000, and 100000, or any range between two values.

[0072] In particular, since repeating unit I contains substituents, the resulting cyclic olefin polymers are not easily stacked, which can effectively eliminate the tendency to crystallize. This prevents the cyclic olefin polymers from becoming cloudy during hydrogenation due to crystallization, thus improving the optical performance of the prepared optical film. Meanwhile, repeating unit II, which does not contain substituents, can ensure the thermal properties of the polymerized cyclic olefin polymers and ensure that its glass transition temperature meets the application requirements.

[0073] In some embodiments, the structure of the cyclic olefin polymer is shown in Formula III:

[0074]

[0075] n = 0 to 10, which means that the value of n can be any value among 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;

[0076] p = 1 to 100000. It can be understood that the value of p can be any value among 1, 10, 100, 10000, 100000 or any range between two values.

[0077] q = 1 to 100000. It can be understood that the value of q can be any value among 1, 10, 100, 10000, and 100000, or any range between two values.

[0078] The cycloolefin polymer provided in this application contains both repeating units with substituents and repeating units without substituents on cycloalkanes. By randomly polymerizing and arranging the two types of repeating units, it is possible to ensure that the cycloolefin polymer does not easily stack in the structure, while avoiding excessive branches from affecting the glass transition temperature of the cycloolefin polymer.

[0079] In some embodiments, the molar ratio of repeating unit I to repeating unit II is 1–9:9–1. When the molar ratio of repeating unit I to repeating unit II meets the above range, it can be ensured that the cyclic olefin polymer formed by polymerization is not prone to crystallization while having an ideal glass transition temperature.

[0080] In some embodiments, the weight-average molecular weight of the cyclic olefin polymer is 5,000 to 150,000, and the molecular weight distribution is 1.2 to 6.0. It is understood that the weight-average molecular weight of the cyclic olefin polymer can be any value or a range between any two of 5,000, 10,000, 100,000, and 150,000. When the molecular weight is too low, the cyclic olefin polymer may crystallize easily, and its strength may not meet requirements. Conversely, when the molecular weight is too high, the melting point of the polymer may increase, while its fluidity may decrease. When the molecular weight of the cyclic olefin polymer meets the above-mentioned range, it ensures that the crystallinity, strength, and melting temperature or glass transition temperature of the cyclic olefin polymer all exhibit ideal performance.

[0081] In some embodiments, the glass transition temperature of the cyclic olefin polymer is 100–155 °C. It is understood that the glass transition temperature (in °C) of the cyclic olefin polymer can be any value or a range between any two of 100, 110, 120, 130, 140, and 155 °C. In subsequent processes for preparing optical films, cyclic olefin polymers with higher glass transition temperatures exhibit better hardness, strength, and thermal stability, while excessively high glass transition temperatures may lead to molding difficulties and reduced processability. Therefore, when the glass transition temperature of the cyclic olefin polymer meets the above-mentioned range, the subsequently formed optical film can possess good strength and stability while being easy to process.

[0082] In some embodiments, the melt index of the cyclic olefin polymer is 5–30 g / 10 min (280°C, 2160 g pressure). It is understood that the melt index (in g / 10 min) of the cyclic olefin polymer can be any value from 5, 10, 15, 20, 25, 30, or a range between any two values. When the melt index of the cyclic olefin polymer meets the above-mentioned range, the cyclic olefin polymer can have ideal flowability in subsequent processing, thereby enabling the optical film to form an ideal thickness.

[0083] The second embodiment of this application provides a method for preparing a cyclic olefin polymer, which is used to prepare the cyclic olefin polymer in any of the above embodiments, and includes the following steps:

[0084] A first monomer and a second monomer are provided and mixed with 1-hexene to carry out the first step reaction, resulting in a reaction solution containing intermediate products.

[0085] The intermediate product was extracted and precipitated, a catalyst was added, and the second step reaction was carried out under heat and pressure to obtain the cyclic olefin polymer.

[0086] Among them, at least one of the first monomer and the second monomer is a non-crystalline monomer.

[0087] By adding 1-hexene to the polymerization reaction of two monomers, the chemical structure and properties of the resulting cyclic olefin polymer can be adjusted. Due to the introduction of 1-hexene, the chain length of the cyclic olefin polymer is changed, thereby giving the final cyclic olefin polymer an ideal melt index.

[0088] In some embodiments, the first monomer is selected from any one of R1-substituted norbornene, tetracyclododecene, and hexacycloheptadecene, and the R1 group is selected from any one of methyl, ethyl, isopropyl, tert-butyl, and phenyl.

[0089] The second monomer is selected from tetracyclododecene or hexacycloheptadecene.

[0090] In some embodiments, the mass ratio of 1-hexene to the sum of the masses of the first monomer and the second monomer is 0.5 to 1.5:100. When the addition ratio of 1-hexene meets the above range, it can ensure that the cyclic olefin polymer is properly modified so that the melt index of the cyclic olefin polymer falls within the preferred range of 5 to 30 g / 10 min (280 degrees Celsius, 2160 g pressure).

[0091] In some embodiments, the catalyst is selected from at least one of molybdenum pentachloride, tungsten hexachloride, and titanium tetrachloride.

[0092] In some embodiments, the second monomer is tetracyclododecene, and the molar ratio of the first monomer to the second monomer is 1-9:9-1.

[0093] In some embodiments, the second monomer is hexacycloheptadecene, and the molar ratio of the first monomer to the second monomer is 2-8:8-2.

[0094] When the selection and addition ratio of the first and second monomers meet the ranges in the above embodiments, it can be ensured that the cyclic olefin polymer obtained by polymerization is not prone to crystallization and has an ideal glass transition temperature.

[0095] In some embodiments, the step of providing the first monomer and the second monomer further includes:

[0096] A third monomer is provided, which is mixed with the first and second monomers;

[0097] The third monomer includes tetracyclododecene or hexacycloheptadecene, and the third monomer is different from the first monomer and the second monomer.

[0098] By adding a third monomer to polymerize the first and second monomers together, the chemical structure and properties of cyclic olefin polymers can be further adjusted, thereby giving them a better glass transition temperature.

[0099] In some embodiments, the molar ratio of the first monomer, the second monomer, and the third monomer is 1–2:3–5:3–5.

[0100] When the selection and addition ratio of the first and second monomers meet the ranges in the above embodiments, it can be further ensured that the cyclic olefin polymer obtained by polymerization is not prone to crystallization and has an ideal glass transition temperature.

[0101] In some embodiments, the temperature of the second reaction step is 140–190°C. It is understood that the temperature of the second reaction step (in °C) can be any value of 140, 150, 160, 170, 180, or 190, or a range between any two values.

[0102] In some embodiments, the pressure of the second reaction step is 4 to 8 MPa. It is understood that the pressure of the second reaction step (in MPa) can be any value of 4, 5, 6, 7, or 8, or a range between any two values.

[0103] When the pressure and temperature of the second reaction step meet the above-mentioned range, it can ensure that the first monomer and the second monomer react completely and avoid the occurrence of side reactions.

[0104] The third embodiment of this application provides an optical film made of the cyclic olefin polymer in any of the above embodiments.

[0105] In some embodiments, the optical film has an in-plane retardation Re, a thickness d, and a thickness direction retardation Rth, satisfying:

[0106] 0.0001≤Re / d≤0.00025;

[0107] And Rth / d≤0.0025.

[0108] Where, Re = (n x -n y )*d;

[0109] Rth=[(n x +n y ) / 2-n z ]*d.

[0110] Re is the in-plane retardation of the membrane, and Rth is the thickness retardation of the membrane.

[0111] n x The refractive index is the direction with the maximum refractive index perpendicular to the thickness direction (in-plane direction) of the film.

[0112] n y To show the direction in the above plane and n x The refractive index in the orthogonal direction.

[0113] n z denoted as , where is the refractive index in the thickness direction.

[0114] Therefore, Re / d characterizes the refractive index difference in different directions within the film surface, while Rth / d characterizes the refractive index difference between the film surface and the thickness direction.

[0115] Re / d and Rth / d are parameters that can be used for selecting optical film processing methods. When the values ​​of Re / d and Rth / d meet the above-mentioned range, the optical film manufactured will have ideal performance in terms of viewing angle, sharpness, and color saturation.

[0116] In some embodiments, Re ≤ 5 nm.

[0117] In some embodiments, 0 ≤ Rth ≤ 50 nm.

[0118] When the in-plane retardation and thickness retardation of the optical film meet the above-mentioned range, it can be ensured that the optical film has an ideal interference effect.

[0119] In some embodiments, 20μm≤d≤60μm.

[0120] When the thickness d of the optical film meets the above-mentioned range, it can be ensured that the optical film has both ideal refractive index and transmittance.

[0121] It is understood that when an optical film is manufactured using the cyclic olefin polymer provided in this application, since the cyclic olefin polymer provided in this application is composed of specific repeating units in appropriate proportions, the crystallinity, glass transition temperature and transmittance of the cyclic olefin polymer are greatly improved, thereby enabling the optical film to meet the above-mentioned value range in terms of optical properties such as in-plane retardation Re, thickness retardation Rth and thickness d.

[0122] The cyclic olefin polymer provided in this application is described below with reference to specific embodiments:

[0123] Example 1

[0124] This embodiment provides a cyclic olefin polymer, prepared by the following method:

[0125] Under inert conditions, 1.25 g of molybdenum pentachloride and 1.25 g of diethyl malonate were dissolved in 10 L of cyclohexane, and the mixture was heated to 55°C. 100 mL of triisobutylaluminum (2 M, n-heptane solution) was slowly added and stirred until homogeneous. The prepared liquid monomer was then thoroughly mixed with 1-hexene and added to the solution over 2 hours. After the addition was complete, the reaction was allowed to proceed for 30 minutes. A sample was taken and the polymer was precipitated using isopropanol. After centrifugation, the supernatant was analyzed by gas chromatography to observe the monomer-to-cyclohexane ratio. No monomer was detected, indicating 100% conversion. The mixture was then washed with water and separated. The organic phase was added to an autoclave, along with 30 g of Ru / C catalyst. The reaction was carried out at 190°C and 6 MPa hydrogen pressure for 5 hours. After the reaction, the sample was dropped onto a membrane and analyzed by infrared absorption spectroscopy. The disappearance of the absorption peak at 975 cm⁻¹ was considered a 100% hydrogenation rate. The hydrogenation catalyst was then removed using a 0.45-micron pore size filter membrane and diatomaceous earth filter cake, and the solution was devolveed and then pelletized.

[0126] Infrared absorption spectroscopy detection and characterization, such as Figure 1 As shown.

[0127] Film casting: COP particles are added to a single-screw cast film, with the screw temperature set to 255 degrees Celsius and the die temperature set to the material's glass transition temperature +110 degrees Celsius. The extrusion and traction speeds are adjusted to obtain films with thicknesses between 50 and 120 micrometers.

[0128] The above-mentioned film was placed in a biaxial stretching machine, the hot air temperature was set to the glass transition temperature -10 degrees Celsius, the stretching ratio in each direction was adjusted according to the experimental requirements, and then the various optical properties were measured.

[0129] Example 2

[0130] Example 2 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 2 As shown.

[0131] Example 3

[0132] Example 3 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 3 As shown.

[0133] Example 4

[0134] Example 4 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 4 As shown.

[0135] Example 5

[0136] Example 5 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 5 As shown.

[0137] Example 6

[0138] Example 6 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 6 As shown.

[0139] Example 7

[0140] Example 7 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 7 As shown.

[0141] Example 8

[0142] Example 8 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 8 As shown.

[0143] Example 9

[0144] Example 9 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows. Figure 9 As shown.

[0145] Example 10

[0146] Example 10 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 10 As shown.

[0147] Comparative Example 1

[0148] Comparative Example 1 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 11 As shown.

[0149] Comparative Example 2

[0150] Comparative Example 2 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 12 As shown.

[0151] Comparative Example 3

[0152] Comparative Example 3 was prepared using the same method as Example 1, except that the selection and amount of monomers were adjusted. The infrared absorption spectroscopy characterization of the prepared cyclic olefin polymer is as follows: Figure 13 As shown.

[0153] The selection and dosage of monomers in Examples 1-10 and Comparative Examples 1-3 are shown in Table 1.

[0154] Table 1

[0155]

[0156] The structural formulas and molecular weights of the cyclic olefin polymers in Examples 1-10 and Comparative Examples 1-3 are shown in Table 2.

[0157] Table 2

[0158]

[0159]

[0160]

[0161] The performance of the above embodiments and comparative examples was tested. The glass transition temperature was quantitatively analyzed using a Netzsch DSC214Polyma differential scanning calorimeter, ranging from room temperature to 200°C, at 10°C·min. -1 The heating rate was controlled under nitrogen protection, and the cycle was repeated twice. The glass transition temperature on the second heating curve was then recorded.

[0162] Haze and visible light transmittance were measured according to standard GB / T 2410-2008. Lower haze indicates lower crystallinity, with an optimal value of 0%. Higher transmittance is better, with an optimal COP value of 92% for COP materials. Tensile strength and elongation at break were measured according to standard GB / T 13022-1991. Higher tensile strength indicates a tougher material, and higher elongation at break indicates that the material is less likely to be damaged after a certain degree of deformation during use.

[0163] The results are shown in Table 3.

[0164] Table 3

[0165]

[0166] As shown in Table 3, the optical films prepared from the cyclic olefin polymers obtained by the scheme provided in this application exhibit ideal performance in terms of glass transition temperature, optical properties, and strength. Examples 9-10 show that using three different monomers to prepare the cyclic olefin polymers effectively increases the glass transition temperature and reduces the crystallization tendency, thereby improving the tensile strength and transmittance of the optical films. Comparative Example 1 shows that when the monomers forming the cyclic olefin polymers do not contain substituents, the haze and transmittance of the final optical film fail to meet requirements. When the proportion of monomers forming the cyclic olefin polymers exceeds the range provided in this application, the glass transition temperature becomes too low, or the transmittance or haze of the optical film is unsatisfactory.

[0167] The foregoing has provided a detailed description of a cyclic olefin polymer, its preparation method, and an optical film provided in the embodiments of this application. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A cyclic olefin polymer, characterized by, comprising a repeating unit I and a repeating unit II, the structural formula of the repeating unit I is shown as formula I: the structural formula of the repeating unit II is shown as formula II: wherein R is selected from any one of methyl, ethyl, isopropyl, tert-butyl and phenyl; n＝0～10； p＝1～100000； q＝1～100000。 2. A cyclic olefin polymer according to claim 1, characterized in that, the structure of the cyclic olefin polymer is shown as formula III: n＝0～10； p＝1～100000； q＝1～100000。 3. The cyclic olefin polymer according to claim 1, characterized in that, the molar ratio of the repeating unit I and the repeating unit II is 1-9:9-1.

4. The cyclic olefin polymer according to claim 1, characterized in that, the weight average molecular weight of the cyclic olefin polymer is 5000-150000, and the molecular weight distribution is 1.2-6.

0.

5. The cyclic olefin polymer according to claim 1, characterized in that, the glass transition temperature of the cyclic olefin polymer is 100-155℃; and / or, the melt index of the cyclic olefin polymer is 5-30 g / 10 min (280℃, 2160 g pressure).

6. A method for producing a cyclic olefin polymer as claimed in any one of claims 1 to 5, characterized by, comprising the following steps: providing a first monomer and a second monomer, mixing with 1-hexene, carrying out a first step reaction to obtain a reaction solution containing an intermediate product; extracting the intermediate product, adding a catalyst, and carrying out a second step reaction under heating and pressure to obtain the cyclic olefin polymer; wherein at least one of the first monomer and the second monomer is a non-crystalline monomer.

7. The method for preparing a cyclic olefin polymer according to claim 6, characterized in that, the first monomer is selected from any one of R1 group substituted norbornene, tetracyclododecene and hexacycloheptadecene, and the R1 group is selected from any one of methyl, ethyl, isopropyl, tert-butyl and phenyl; the second monomer is selected from tetracyclododecene or hexacycloheptadecene.

8. The method for preparing a cyclic olefin polymer according to claim 6, characterized in that, the mass ratio of the 1-hexene to the mass sum of the first monomer and the second monomer is 0.5-1.5:

100.

9. The method for preparing a cyclic olefin polymer according to claim 6, characterized in that, the catalyst is selected from at least one of molybdenum pentachloride, tungsten hexachloride and titanium tetrachloride.

10. The method for preparing a cyclic olefin polymer according to claim 7, characterized in that, the second monomer is tetracyclododecene, and the molar ratio of the first monomer to the second monomer is 1-9:9-1; or, the second monomer is hexacycloheptadecene, and the molar ratio of the first monomer to the second monomer is 2-8:8-2.

11. The method for preparing a cyclic olefin polymer according to claim 7, characterized in that, in the step of providing the first monomer and the second monomer, further comprising: providing a third monomer, mixing with the first monomer and the second monomer; wherein the third monomer comprises tetracyclododecene or hexacycloheptadecene, and the third monomer is different from the first monomer and the second monomer respectively.

12. The method of claim 11, wherein the ring-opening metathesis polymerization is carried out in the presence of a catalyst selected from the group consisting of Grubbs catalyst, Hoveyda-Grubbs catalyst, and mixtures thereof. the molar ratio of the first monomer, the second monomer and the third monomer is 1-2:3-5:3-5.

13. The method for preparing a cyclic olefin polymer according to claim 5, characterized in that, the temperature of the second step reaction is 140-190℃; and / or, the pressure of the second step reaction is 4-8 MPa.

14. An optical film characterized by, made of the cyclic olefin polymer of any one of claims 1-5, or made by the preparation method of any one of claims 6-13.

15. The optical film of claim 14, wherein, the optical film has an in-plane retardation Re, a thickness d and a thickness direction retardation Rth, and satisfies: 0.0001≤Re / d≤0.00025; and Rth / d≤0.0025.

16. The optical film of claim 15, wherein, the in-plane retardation Re, the thickness d and the thickness direction retardation Rth further satisfy: Re≤5 nm; and / or, 0≤Rth≤50 nm; and / or, 20 μm≤d≤60 μm.

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