Cycloolefin polymer, preparation method thereof and optical film

Abstract

The invention provides a cycloolefin polymer, a preparation method thereof and an optical film. The cycloolefin polymer comprises a repetitive unit I, a repetitive unit II and a repetitive unit III, wherein the polymerization degrees of the repetitive unit I, the repetitive unit II and the repetitive unit III satisfy 0 < p / (p + q + r) < = 0.55. According to the cycloolefin polymer provided by the invention, bridge methylene tetrahydrofluorene, bridge methylene hexahydrophenanthrene or derivatives thereof are used, and the polymerization ratio of three repetitive units is controlled, so that the formed cycloolefin polymer can be effectively ensured not to have a crystallization trend in a hydrogenation process, the haze of a product is reduced, and the yield of the product is improved. And meanwhile, the formed cycloolefin polymer is ensured to have a good glass transition temperature.

Description

Technical Field

[0001] This application belongs to the field of optical film manufacturing technology, specifically relating to a cyclic olefin polymer and its preparation method, and an optical film. Background Technology

[0002] COP (Cyclic Olefin Polymer) is a material obtained by ring-opening metathesis polymerization of cyclic olefins, followed by hydrogenation to saturate all unsaturated bonds on the polymer. COP possesses a series of excellent properties such as high heat distortion temperature, high transparency, low birefringence, and low dielectric loss, making it an important material for the fabrication of various optical components.

[0003] COP is usually obtained by polymerization of monomers such as norbornene, with a glass transition temperature between 90°C and 150°C. However, existing COP is prone to turbidity or even gelation during hydrogenation, resulting in low light transmittance and unsatisfactory 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 and thermal properties of optical films, is a problem that needs to be solved. Summary of the Invention

[0005] This invention provides a cyclic olefin polymer, its preparation method, and an optical film. It aims to solve the problem in existing optical film manufacturing fields where COP (Coefficient of Performance) cannot simultaneously achieve ideal thermal and optical properties.

[0006] The first embodiment of this application provides a cyclic olefin polymer, comprising repeating unit I, repeating unit II, and repeating unit III, wherein the structural formula of repeating unit I is shown in Formula I:

[0007]

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

[0009]

[0010] The structural formula of the repeating unit III is shown in Formula III:

[0011]

[0012] R1 and R2 are each independently selected from any one of hydrogen atoms, C1-C6 saturated straight-chain alkyl groups, or C1-C6 cycloalkyl groups;

[0013] n = 0 to 2;

[0014] 0 < p / (p+q+r) ≤ 0.55, where p ≥ 1, q ≥ 1, and r ≥ 0.

[0015] In some embodiments, the cyclic olefin polymer has the structural formula shown in Formula IV:

[0016]

[0017] In some embodiments, p, q, and r further satisfy:

[0018] p = 1 to 100000;

[0019] q = 1 to 200,000;

[0020] r = 0 ~ 200000.

[0021] In some embodiments, R1 and R2 are each independently selected from hydrogen atoms, methyl groups, or ethyl groups.

[0022] In some embodiments, the cyclic olefin polymer has a weight-average molecular weight of 5,000 to 200,000 and a molecular weight distribution of 1.2 to 5.

[0023] In some embodiments, the glass transition temperature of the cyclic olefin polymer is 110–155°C.

[0024] In some embodiments, the melt index of the cyclic olefin polymer is 5 to 30 g / 10 min (280 degrees Celsius, 2160 g pressure).

[0025] The second embodiment of this application provides a method for preparing a cyclic olefin polymer, comprising the following steps:

[0026] A first monomer, a second monomer, and a third monomer are provided and mixed with 1-hexene to carry out the first step of the reaction, resulting in a reaction solution containing intermediate products.

[0027] The reaction solution was de-hexene removed, a hydrogenation catalyst was added, and a second reaction was carried out under a hydrogen atmosphere to obtain the cyclic olefin polymer.

[0028] Among them, at least one of the first monomer, the second monomer and the third monomer is an amorphous monomer.

[0029] In some embodiments, the structural formula of the first monomer is shown in formula V:

[0030]

[0031] The second monomer is dicyclopentadiene;

[0032] The third monomer is tetracyclododecene.

[0033] In some embodiments, the molar ratio of the first monomer, the second monomer, and the third monomer is 5–55:45–95:45–95.

[0034] In some embodiments, the temperature of the second step reaction is 140–190°C.

[0035] In some embodiments, the hydrogen pressure in the second step reaction is 4–8 MPa.

[0036] The third embodiment of this application provides an optical film made of the cyclic olefin polymer in any of the above embodiments.

[0037] In some embodiments, the haze of the optical film is 0.

[0038] In some embodiments, the transmittance of the optical film is 90% to 92%.

[0039] This application provides a cyclic olefin polymer comprising repeating unit I, repeating unit II, and repeating unit III, wherein the degree of polymerization of repeating unit I, repeating unit II, and repeating unit III satisfies 0 < p / (p+q+r) ≤ 0.55, where p ≥ 1, q ≥ 1, and r ≥ 0. The cyclic olefin polymer provided in this application, by using bridged methylenetetrahydrofluorene, bridged methylenehexahydrophenanthrene, or derivatives thereof, and by controlling the polymerization ratio of the three repeating units, effectively ensures that the formed cyclic olefin polymer does not exhibit a crystallization tendency during hydrogenation, thereby reducing the haze of the product and ensuring that the formed cyclic olefin polymer has a good glass transition temperature. Attached Figure Description

[0040] 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.

[0041] Figure 1 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 1 of this application;

[0042] Figure 2 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 2 of this application;

[0043] Figure 3 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 3 of this application;

[0044] Figure 4 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 4 of this application;

[0045] Figure 5 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 5 of this application;

[0046] Figure 6 The infrared absorption spectrum of a cyclic olefin polymer provided in Example 6 of this application;

[0047] Figure 7 Infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 1 of this application;

[0048] Figure 8 Infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 2 of this application;

[0049] Figure 9 The infrared absorption spectrum of a cyclic olefin polymer provided for Comparative Example 3 of this application is shown. Detailed Implementation

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The first embodiment of this application provides a cyclic olefin polymer, including repeating unit I, repeating unit II, and repeating unit III, wherein the structural formula of repeating unit I is shown in Formula I:

[0054]

[0055] The structural formula of repeating unit II is shown in Equation II:

[0056]

[0057] The structural formula of repeating unit III is shown in Equation III:

[0058]

[0059] R1 and R2 are each independently selected from any one of hydrogen atoms, C1-C6 saturated straight-chain alkyl groups, or C1-C6 cycloalkyl groups;

[0060] n = 0 to 2;

[0061] 0 < p / (p+q+r) ≤ 0.55;

[0062] Where p is an integer greater than or equal to 1, q is an integer greater than or equal to 1, and r is an integer greater than or equal to 0.

[0063] Because repeating unit I contains substituents, the resulting cyclic olefin polymers are less likely to stack in space, thereby reducing the crystallization tendency of the cyclic olefin polymers and preventing turbidity due to crystallization during hydrogenation. By controlling the polymerization ratio of the three repeating units, the haze of the final product can be reduced, while ensuring that the formed cyclic olefin polymer has a good glass transition temperature.

[0064] In some embodiments, the structural formula of the cyclic olefin polymer is shown in Formula IV:

[0065]

[0066] In some embodiments, p, q, and r further satisfy:

[0067] p is a natural number between 1 and 100000;

[0068] q is a natural number between 1 and 200,000;

[0069] r is a natural number between 0 and 200000.

[0070] It is understandable that the value of p can be any value or a range between any two of 1, 100, 1000, 10000, 100000; the value of q can be any value or a range between any two of 1, 100, 1000, 10000, 100000, 200000; and the value of r can be any value or a range between any two of 0, 1, 100, 1000, 10000, 100000, 200000. When p, q, and r satisfy the above value ranges, the crystallization tendency of the polymer can be suppressed, maintaining isotropic characteristics even before and after hydrogenation. This ensures that the material maintains stable optical properties during various forming and processing processes, and preserves the good mechanical properties of the polymer.

[0071] In some embodiments, R1 and R2 are each independently selected from hydrogen atoms, methyl or ethyl atoms.

[0072] In some embodiments, the weight-average molecular weight of the cyclic olefin polymer is 5,000 to 200,000, and the molecular weight distribution is 1.2 to 5. 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, 150,000, and 200,000. When the molecular weight is too low, the cyclic olefin polymer may easily crystallize, and its strength may not meet requirements. Conversely, when the molecular weight is too high, it may increase the polymer's melting point and reduce its fluidity. 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.

[0073] In some embodiments, the glass transition temperature of the cyclic olefin polymer is 110–155 °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 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.

[0074] 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.

[0075] The second embodiment of this application provides a method for preparing a cyclic olefin polymer, comprising the following steps:

[0076] A first monomer, a second monomer, and a third monomer are provided and mixed with 1-hexene to carry out the first step reaction, yielding a reaction solution containing intermediate products.

[0077] The reaction solution of the intermediate obtained above was de-hexene removed, a hydrogenation catalyst was added, and the second step reaction was carried out under heating and pressure in a hydrogen atmosphere to obtain a cyclic olefin polymer.

[0078] Among them, at least one of the first monomer, the second monomer, and the third monomer is an amorphous monomer.

[0079] 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 and side chain structure of the cyclic olefin polymer are changed, thereby giving the final cyclic olefin polymer an ideal melt index.

[0080] In some embodiments, the structural formula of the first monomer is shown in formula V:

[0081]

[0082] The second monomer is dicyclopentadiene;

[0083] The third monomer is tetracyclododecene.

[0084] In some embodiments, the molar ratio of the first monomer, the second monomer, and the third monomer is 5–55:45–95:45–95. When the molar ratio of the first monomer, the second monomer, and the third monomer satisfies the above ratio, it can be ensured that each repeating unit in the final cyclic olefin polymer has an ideal polymerization ratio, thereby ensuring that the final cyclic olefin polymer has no tendency to crystallize while having a good glass transition temperature.

[0085] 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.

[0086] In some embodiments, the hydrogen pressure in the second step reaction is 4–8 MPa. It is understood that the hydrogen pressure (unit: MPa) can be any value of 4, 5, 6, 7, or 8, or a range between any two values.

[0087] When the hydrogen pressure and temperature of the second reaction 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.

[0088] The third embodiment of this application provides an optical film made of the cyclic olefin polymer in any of the above embodiments.

[0089] In some embodiments, the haze of the optical film is 0.

[0090] The haze of an optical film refers to the scattering ability of the material, that is, the degree to which light is scattered in the material. High haze means that light will be strongly scattered in the optical film, resulting in a decrease in the quality of transmitted light. When the haze of the optical film is low enough, it can provide a high transmission quality, making the transmitted light clearer.

[0091] In some embodiments, the transmittance of the optical film is 90% to 92%.

[0092] The transmittance of an optical film refers to the proportion of light that passes through it. When the transmittance meets the above-mentioned range, it ensures that the optical device has ideal optical transmission efficiency and brightness.

[0093] 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, thickness d, haze and transmittance.

[0094] The cyclic olefin polymer provided in this application is described below with reference to specific embodiments:

[0095] Example 1

[0096] This embodiment provides a cyclic olefin polymer, prepared by the following method:

[0097] 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.

[0098] The infrared absorption spectroscopy detection characterization is as follows:

[0099] 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.

[0100] 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.

[0101] Example 2

[0102] 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 shown in Figure 2.

[0103] Example 3

[0104] 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 shown in Example 3.

[0105] Example 4

[0106] 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.

[0107] Example 5

[0108] 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.

[0109] Example 6

[0110] 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.

[0111] Comparative Example 1

[0112] 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 7 As shown.

[0113] Comparative Example 2

[0114] 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 8 As shown.

[0115] Comparative Example 3

[0116] 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 9 As shown.

[0117] The selection and dosage of monomers in Examples 1-10 and Comparative Examples 1-3 are shown in Table 1.

[0118] Table 1

[0119]

[0120]

[0121] The structural formulas and molecular weights of the cyclic olefin polymers in Examples 1-6 and Comparative Examples 1-3 are shown in Table 2.

[0122] Table 2

[0123]

[0124]

[0125]

[0126] Performance tests were performed on the above embodiments and comparative examples.

[0127] Glass transition temperature was quantitatively analyzed using a Netzsch DSC 214 Polyma differential scanning calorimeter at a room temperature of approximately 200°C, at a rate of 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.

[0128] 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.

[0129] The results are shown in Table 3.

[0130] Table 3

[0131]

[0132]

[0133] 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 1-5 demonstrate that using three different monomers to prepare the cyclic olefin polymers not only effectively increases the glass transition temperature and reduces the crystallization tendency, thereby improving the tensile strength and transmittance of the optical films, but also enhances the tensile strength and elongation at break of the optical films. Comparative Examples 2-3 show that when the proportion of monomers forming the cyclic olefin polymer exceeds the range provided in this application, it leads to unsatisfactory transmittance or haze performance of the optical films, or the materials become too brittle and fail to meet the tensile strength requirements.

[0134] 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, a repeating unit II and a repeating unit III, the repeating unit I having a structural formula as shown in formula I: the repeating unit II having a structural formula as shown in formula II: the repeating unit III having a structural formula as shown in formula III: wherein R1 and R2 are each independently selected from any one of a hydrogen atom, a C1-C6 saturated linear alkyl group or a C1-C6 cyclic alkyl group; n＝0～2； 0 < p / (p+q+r) ≤ 0.55, wherein p ≥ 1, q ≥ 1, and r ≥ 0.

2. A cyclic olefin polymer according to claim 1, characterized in that, the cycloolefin polymer having a structural formula as shown in formula IV:

3. The cyclic olefin polymer according to claim 1, characterized in that, the p, q and r further satisfy: p＝1～100000； q＝1～200000； r＝0～200000。 4. The cyclic olefin polymer according to claim 1, characterized in that, the R1 and R2 are each independently selected from a hydrogen atom, a methyl group or an ethyl group.

5. The cyclic olefin polymer according to claim 1, characterized in that, the cycloolefin polymer having a weight average molecular weight of 5000-200000 and a molecular weight distribution of 1.2-5; the cycloolefin polymer having a glass transition temperature of 110-155℃; and / or, the cycloolefin polymer having a melt index of 5-30 g / 10min (280℃, 2160g 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, a second monomer and a third monomer, mixing with 1-hexene, carrying out a first step reaction to obtain a reaction liquid containing an intermediate product; removing 1-hexene from the reaction liquid, adding a hydrogenation catalyst, and carrying out a second step reaction in a hydrogen atmosphere to obtain the cycloolefin polymer; wherein at least one of the first monomer, the second monomer and the third 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 having a structural formula as shown in formula V: the second monomer being dicyclopentadiene; the third monomer being tetracyclododecene.

8. The method for preparing a cyclic olefin polymer according to claim 6, characterized in that, the molar ratio of the first monomer, the second monomer and the third monomer being 5-55:45-95:45-95.

9. The method for preparing a cyclic olefin polymer according to claim 6, characterized in that, the temperature of the second step reaction being 140-190℃, the hydrogen pressure of the second step reaction being 4-8 MPa.

10. An optical film characterized by, the cycloolefin polymer being made of the cycloolefin polymer as claimed in any one of claims 1-5, or made by the preparation method as claimed in any one of claims 6-9.

11. The optical film of claim 10, wherein, the optical film having a haze of 0; the optical film having a light transmittance of 90%-92%.

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