JP2023133776A - Cycloolefin polymer, method for producing the same, and application of the same - Google Patents

Abstract

To provide a cycloolefin polymer which enables production of an optical material excellent in low birefringence and surface workability and includes a lactone structure, a method for producing the same, an optical resin material composed of the cycloolefin polymer, and an optical molding obtained by molding the optical resin material.SOLUTION: A cycloolefin polymer includes a new specific lactone structure.SELECTED DRAWING: None

Description

The present invention relates to a cycloolefin polymer, a method for producing the same, and uses thereof.

In recent years, lenses, films, etc. made of cycloolefin polymers have been used for optical lenses for smartphones, polarizing plate protective films, liquid crystal substrate materials, etc. due to their relatively low birefringence. For example, hydrogenated ring-opening polymers of tetracyclododecenes and 1,4-methano-1,4,4a,9a-tetrahydrofluorene have been proposed as cycloolefin polymers with excellent low birefringence (patent References 1 and 2).

Optical lenses for smartphones are manufactured using injection molding, so birefringence occurs due to stress generated during molding. When birefringence occurs, the refractive index within the lens becomes non-uniform, resulting in large aberrations and poor imaging performance. Therefore, in order to improve the imaging performance of the lens, it is necessary to use a material that does not easily exhibit birefringence even when stress is applied.

A polarizing plate protective film is a film normally used to protect a polarizer (PVA film + iodine). A polarizing plate protective film must not change the state of polarization and must have a low retardation.

These optical lenses, films, etc. are subjected to AR (Anti-Reflection) treatment to suppress reflectance, or are bonded to other materials using adhesives, adhesives, etc., so surface treatments are required. Sex is required.

For example, various cycloolefin polymers with low birefringence have been proposed (Patent Documents 3 and 4).

However, in the conventional technology, the surface processability necessary for processing lenses, films, etc. is sometimes inferior, and there is a need for a cycloolefin polymer that has both low birefringence and excellent surface processability.

Special Publication No. 2-9619 WO96/10596 publication Japanese Patent Application Publication No. 10-287713 Japanese Patent Application Publication No. 2005-330465

The objects of the present invention are a cycloolefin polymer containing a lactone structure capable of producing an optical material having low birefringence and excellent surface workability, a method for producing the same, an optical resin material composed of the cycloolefin polymer, and an optical resin material including the cycloolefin polymer. An object of the present invention is to provide an optical molded body formed by molding a material.

As a result of intensive studies to achieve the above object, the present inventors found that a cycloolefin polymer containing a specific new lactone structure has low birefringence and excellent The present invention was completed based on the discovery that the material has excellent surface workability.

That is, the present invention includes the following configurations.

Item 1.
A cycloolefin polymer containing a structural unit represented by the following general formula (1).

(In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.)
Item 2.
The cycloolefin polymer according to claim 1, wherein in the general formula (1), R ¹ to R ⁸ are hydrogen.

Item 3.
A molded article containing the cycloolefin polymer according to item 1 or 2 above.

Item 4.
3. The molded article according to item 3, which is an optical film or an optical lens.

Item 5.
A method for producing a cycloolefin polymer, the method comprising:
(1) 4-oxa-endo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (endo-NBL) or 4-oxa-exo in the presence of a third generation Grubbs catalyst in a solvent -tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (exo-NBL), including a step of ring-opening polymerization reaction,
H-poly(endo-NBL) cycloolefin polymer (or poly(endo-NBL) cycloolefin polymer) or H-poly(exo-NBL) cycloolefin polymer containing a structural unit represented by the following general formula (1) (or poly(exo-NBL) cycloolefin polymer).

(In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.)
Item 6.
Furthermore, (2) in a solvent, in the presence of a hydrogenation catalyst, the H-poly(endo-NBL) cycloolefin polymer (or poly(endo-NBL) cycloolefin polymer) obtained in the step (1) or H -Includes a step of hydrogenating poly(exo-NBL) cycloolefin polymer (or poly(exo-NBL) cycloolefin polymer),
The method for producing a cycloolefin polymer according to item 5 above.

A hydrogenated H-poly(endo-NBL) cycloolefin polymer or a hydrogenated H-poly(exo-NBL) cycloolefin polymer can be obtained by the hydrogenation reaction.

The present invention provides a cycloolefin polymer containing a lactone structure with low birefringence and excellent surface workability, a method for producing the same, an optical resin material made of this cycloolefin polymer, and an optical molded article formed by molding this optical resin material. be.

The cycloolefin polymer containing a lactone structure of the present invention has low birefringence and excellent surface processability.

The cycloolefin polymer containing a lactone structure of the present invention has excellent imaging performance and excellent adhesion with other materials, and can be suitably used for optical lenses. It has excellent adhesion with other materials and can be suitably used for optical films.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to this, and various modifications can be made without departing from the gist thereof.

As used herein, "comprise" and "containing" include "comprise," "consist essentially of," and "consist of." It is a concept.

In this specification, when a numerical range is indicated as "A to B", it means "above A and below B".

1. Cycloolefin polymer The present invention is a cycloolefin polymer containing a structural unit represented by the following general formula (1), and is a cycloolefin polymer containing a lactone structure.

In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.

The substituent preferably represents an atom or group consisting of a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group.

The aliphatic hydrocarbon group (hydrocarbon group) is preferably a straight chain group having 1 to 4 carbon atoms such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, etc. or branched alkyl group, with 5 to 30 carbon atoms such as n-pentyl, iso-pentyl, sec-pentyl, tert-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, etc. is a straight-chain or branched alkyl group.

The alicyclic hydrocarbon group is preferably a monocyclic or bicyclic alicyclic hydrocarbon group. Monocyclic alicyclic hydrocarbon groups are preferably cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, 2,6-dimethylcyclohexyl, 3,5-dimethylcyclohexyl, 4-tert-butylcyclohexyl, It is a hydrocarbon group having a monocyclic alicyclic skeleton having 3 to 30 carbon atoms, such as cycloheptyl, cyclooctyl, and cyclododecyl. The bicyclic alicyclic hydrocarbon group is preferably bicyclo[1.1.0]butyl, bicyclo[2.1.0]pentyl, norbornyl, bicyclo[2.2.2]octyl, spiro[2 .2] A hydrocarbon group having a bicyclic alicyclic skeleton having 5 to 30 carbon atoms, such as pentyl and spiro[2.3]hexyl.

The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, such as phenyl, benzyl, naphthyl, biphenylyl, triphenylyl, fluorenyl, anthranyl, phenanthryl.

In formula (1), R ⁷ and R ⁸ may be bonded via an alkylene group or may be bonded without any group.

In the cycloolefin polymer of the present invention, R ¹ to R ⁸ in formula (1) are more preferably hydrogen.

2. Physical properties of cycloolefin polymer
Glass transition temperature (Tg)
Using a differential scanning calorimeter, a sample is placed in an aluminum pan, and the glass transition temperature (Tg (°C)) of the cycloolefin polymer is measured in the range of 30°C to 200°C in accordance with JIS K 7121.

The Tg of the cycloolefin polymer of the present invention is preferably 110°C to 180°C, more preferably 120°C to 170°C, even more preferably 130°C to 165°C, particularly preferably 130°C. ℃～150℃.

Molecular weight (Mw)
Using gel permeation chromatography, the sample is dissolved in N,N-dimethylformamide, and the weight average molecular weight (Mw) of the cycloolefin polymer is measured in terms of poly(methyl methacrylate).

The Mw of the cycloolefin polymer of the present invention is preferably 20,000 to 80,000, more preferably 25,000 to 60,000, and even more preferably 30,000 to 50,000. .

The refractive index of the cycloolefin polymer is measured by the refractive index immersion method.

The refractive index of the cycloolefin polymer of the present invention is preferably 1.4 to 1.6, more preferably 1.45 to 1.55, and still more preferably 1.50 to 1.54. be.

Using a birefringence stretching device, the cycloolefin polymer is uniaxially stretched at the free end under the conditions of Tg + 20°C, magnification of 2 times, and speed of 300%/min. Using a retardation measuring device, the Ro (600) of the stretched film is measured at a measurement temperature of 20° C., and the birefringence of the stretched film of the cycloolefin polymer is calculated by dividing it by the film thickness.

The birefringence of the cycloolefin polymer of the present invention is preferably from 0.01×10 ⁻³ to 1×10 ⁻³ , more preferably from 0.02×10 ⁻³ to 0.8×10 ⁻³ . It is more preferably 0.04×10 ⁻³ to 0.6×10 ⁻³ , particularly preferably 0.06×10 ⁻³ to 0.3×10 ⁻³ .

The cycloolefin polymer of the present invention has low birefringence, and molded articles made using it exhibit excellent optical properties and are useful as optical members such as optical films (or optical sheets) and optical lenses. It is.

Contact Angle Using a contact angle meter, water and diiodomethane are dropped onto a stretched film test piece of a cycloolefin polymer, and the contact angle (°) of the test piece is measured.

Water is dropped onto a stretched film test piece of cycloolefin polymer, and the contact angle of the test piece is preferably 69° to 88°, more preferably 71° to 86°, and even more preferably 73°. The angle is preferably from 75° to 84°, particularly preferably from 75° to 82°.

Diiodomethane is dropped onto a stretched film test piece of cycloolefin polymer, and the contact angle of the test piece is preferably 44 to 62°, more preferably 46° to 60°, and even more preferably 48°. ~58°, particularly preferably from 50° to 56°.

The cycloolefin polymer of the present invention has excellent surface processability (wettability), excellent imaging performance, and excellent adhesion to other materials.

3. Method for producing cycloolefin polymer
3-1. Production method of cycloolefin polymer raw materials (endo-NBL and exo-NBL)
Method for producing endo-NBL (endo-norbornene lactones) Under a nitrogen atmosphere, sodium borohydride is charged in a solvent (tetrahydrofuran, methanol, etc.), and cis-5-norbornene-endo-2,3-dicarboxylic acid is used as a raw material. By mixing anhydride (cis-5-Norbornene-endo-2,3-dicarboxylic anhydride), 4-oxa-endo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one ( endo-NBL).

Method for producing exo-NBL (exo-norbornene lactones) Under a nitrogen atmosphere, sodium borohydride is charged in a solvent (tetrahydrofuran, methanol, etc.), and cis-5-norbornene-exo-2,3-dicarboxylic acid is used as a raw material. By mixing anhydride (cis-5-Norbornene-exo-2,3-dicarboxylic anhydride), 4-oxa-exo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one ( exo-NBL) can be obtained.

3-2. Manufacturing method of cycloolefin polymer The cycloolefin polymer of the present invention may be manufactured using a generally known ring-opening polymerization method (ring-opening metathesis polymerization (ROMP)). Can be polymerized.

The metathesis polymerization catalyst can be selected from known catalysts such as Grubbs Catalyst. For example, Grubbs Catalyst 3rd Generation (Dichloro[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene ](benzylidene)bis(3-bromopyridine)ruthenium(II)).

Method for producing poly(endo-NBL) by ring-opening polymerization reaction The method for producing the cycloolefin polymer of the present invention includes (1) using a Grubbs Catalyst (R) 3rd Generation in a solvent (dichloromethane, etc.); A cycloolefin polymer comprising a step of ring-opening polymerization (ROMP) of 4-oxa-endo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (endo-NBL) in the presence of (poly(endo-NBL)).

Method for producing poly(exo-NBL) by ring-opening polymerization reaction The method for producing the cycloolefin polymer of the present invention includes (1) using a Grubbs Catalyst (R) 3rd Generation in a solvent (dichloromethane, etc.); A cycloolefin polymer comprising a step of ring-opening polymerization (ROMP) of 4-oxa-exo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (exo-NBL) in the presence of (poly(exo-NBL)).

Hydrogenation
The cycloolefin polymer (poly(endo-NBL)) or cycloolefin polymer (poly(exo-NBL)) may be hydrogenated.

The method for producing a cycloolefin polymer of the present invention further includes (2) the presence of a hydrogenation catalyst (homogeneous catalyst such as RuHCl(CO)(PPh ₃ ) ₃ ) in the solvent (o-xylene, etc.). Below, hydrogenated cycloolefin polymer (H- This is a method for producing poly(endo-NBL) or H-poly(exo-NBL).

The present invention is a method for producing a cycloolefin polymer containing a structural unit represented by the following general formula (1).

In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.

4. Molded product containing cycloolefin polymer The molded product of the present invention contains the cycloolefin polymer of the present invention and exhibits excellent optical properties, so it can be used as optical members such as optical films (or optical sheets) and optical lenses. .

The molded article of the present invention may contain conventional additives.

Examples of additives include fillers or reinforcing agents such as carbon materials, colorants such as dyes and pigments, conductive agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, dispersants, fluidity regulators, It may contain a leveling agent, an antifoaming agent, a surface modifier, a hydrolysis inhibitor, a stabilizer, a stress reducing agent, and the like.

Examples of the stabilizer include antioxidants, ultraviolet absorbers, and heat stabilizers.

Examples of the stress reducing agent include silicone oil, silicone rubber, various plastic powders, and various engineering plastic powders.

These additives may be used alone or in combination of two or more.

The molded article can be manufactured using, for example, an injection molding method, an injection compression molding method, an extrusion molding method, a transfer molding method, a blow molding method, a pressure molding method, a casting molding method, or the like.

The shape of the molded object is not particularly limited, and includes, for example, one-dimensional structures such as linear, fibrous (or fibrous), and thread-like structures, two-dimensional structures such as film-like, sheet-like, and plate-like structures, and concave or convex lenses. Examples include three-dimensional structures such as a shape, a rod shape, and a hollow shape (tubular shape).

The resin of the present invention contains the above-mentioned cycloolefin polymer and has excellent various optical properties, so it is useful for forming an optical film. The present invention includes a film (optical film or optical sheet) formed of the resin.

The average thickness of the film of the present invention can be selected from the range of about 1 μm to 1,000 μm depending on the application, for example, 1 μm to 200 μm, preferably 5 μm to 150 μm, and more preferably 10 μm to 120 μm.

The film (optical film) can be produced by forming (or molding) the resin using a conventional film forming method, for example, a casting method (solvent casting method), a melt extrusion method, a calender method, or the like.

The film of the present invention is preferably a stretched film. The film of the present invention can maintain low birefringence even if it is a stretched film. The stretched film may be either a uniaxially stretched film or a biaxially stretched film.

The molded article of the present invention may be joined or bonded to another base material, and the type, material, etc. of the base material are not particularly limited. The type, material, etc. of the base material may be, for example, a one-dimensional, two-dimensional, or three-dimensional base material made of a resin material, a ceramic material, a metal material, or the like.

When the molded article is in the form of a film, it may be combined with a two-dimensionally shaped base material such as a film to form a laminate or a laminated film.

The present invention will be specifically explained based on Examples.

The present invention is not limited to these examples.

The evaluation method, raw materials, and cycloolefin polymer are shown below.

1. Evaluation method (glass transition temperature (Tg))
Using a differential scanning calorimeter ("DSC7000X" manufactured by HITACHI), a sample was placed in an aluminum pan, and the Tg of the sample was measured in the range of 30°C to 200°C in accordance with JIS K 7121.

(molecular weight)
Using gel permeation chromatography (“EXTREMA” manufactured by JASCO), the sample was dissolved in N,N-dimethylformamide (5.75 mmol/L, LiBr), and the weight average molecular weight Mw of the sample was determined in terms of poly(methyl methacrylate). It was measured.

(Refractive index)
The refractive index of the sample was measured by the immersion method.

(birefringence)
Using a stretching device, the produced test piece was uniaxially stretched at the free end under the conditions of Tg + 20°C, magnification of 2 times, and speed of 300%/min. Using a retardation measuring device (“RETS-100” manufactured by Otsuka Electronics Co., Ltd.), measure the Ro (600) of the stretched film at a measurement temperature of 20°C, and divide it by the film thickness. The refraction was calculated.

(contact angle)
Using a contact angle meter (“DMo-501” manufactured by Kyowa Interface Science Co., Ltd.), water and diiodomethane were dropped onto the prepared test piece, and the contact angle of the test piece was measured.

2. Synthesis of endo-NBL and exo-NBL (Synthesis example 1: Synthesis of endo-NBL (endo-norbornene lactones))
A reactor equipped with a stirrer chip, a dropping funnel, and a three-way cock was charged with sodium borohydride (5.76 g, 152 mmol) and purged with nitrogen, and then tetrahydrofuran (110 mL) was added and stirred and dispersed at -10°C.

In a separate container, under a nitrogen atmosphere, cis-5-Norbornene-endo-2,3-dicarboxylic anhydride (25.0 g, 152 mmol), Tetrahydrofuran (80 mL) and methanol (6 mL) were mixed, and this was added dropwise to a solution of sodium borohydride in tetrahydrofuran over 60 minutes, followed by stirring at -10°C for 1 hour.

At 0°C, 2M hydrochloric acid (89 mL) was added over 30 minutes. The organic layer was extracted using dichloromethane, washed with water, and the organic layer was dried over sodium sulfate.

By filtering off the sodium sulfate and distilling off the organic solvent under reduced pressure, a white solid 4-oxa-endo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (endo-NBL) ( 15.25 g, yield 67%) was obtained.

(Synthesis Example 2: Synthesis of exo-NBL (exo-norbornene lactones))
By the same method as endo-NBL of Synthesis Example 1, cis-5-Norbornene-exo-2,3-dicarboxylic anhydride (25.0 g , 152 mmol), 4-oxa-exo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (exo-NBL) (18.2 g, yield 86%) was obtained.

3. Example (Example 1)
Under a nitrogen atmosphere, Grubbs Catalyst(R) 3rd Generation (235 mg, 0.267 mol) and dry dichloromethane (25 mL) were added to a reactor containing a stirrer chip and stirred to dissolve.

Endo-NBL (4.00 g, 26.6 mmol) of Synthesis Example 1 was added to another reactor, and a three-way cock was installed to perform nitrogen substitution, and dry dichloromethane (80 mL) was added as a solvent to prepare a monomer solution. The monomer solution was taken out with a syringe, added to the catalyst solution cooled to 0° C., and stirred for 2 hours. Polymerization was stopped by adding a small amount of ethyl vinyl ether and stirring at room temperature for 30 minutes.

Thereafter, the solid obtained by reprecipitation in methanol was dried under heating and reduced pressure to obtain 3.58 g of a cycloolefin polymer (poly(endo-NBL)) as a white powder.

3.58 g of poly(endo-NBL) and dry N,N-dimethylacetamide (97 mL) were added to a glass container and stirred to dissolve. Dry o-xylene (71 mL) was added portionwise with stirring to suspend the solution. Then, a small amount of dibutylhydroxytoluene (BHT) and RuHCl(CO)(PPh ₃ ) ₃ (473 mg, 0.50 mol) were added, and the container was transferred to a stainless steel autoclave and sealed.

The inside of the reaction vessel was replaced with hydrogen (1.0 MPa), and the mixture was stirred for 8 hours at an oil bath temperature of 135°C. The reaction vessel was returned to room temperature, and the polymerization solution was precipitated in methanol to obtain a polymer, which was dried under heat and reduced pressure. The obtained polymer was hydrogenated again under the same conditions to recover a cycloolefin polymer (H-poly(endo-NBL)) with a conversion rate of 97%.

It was purified by Soxhlet extraction using methanol to obtain 2.52 g of a white powder polymer with a yield of 70%. The Mw of the polymer was 37,000.

After drying the produced polymer, it was made into a solution using methylene chloride, and a test piece for birefringence measurement was produced by casting film. In addition, a test piece for contact angle measurement was prepared by spin coating on a silicon wafer.

(Example 2)
Under a nitrogen atmosphere, Grubbs Catalyst(R) 3rd Generation (147 mg, 0.17 mol) and dry dichloromethane (33 mL) were added to a reactor containing a stirrer chip, and the mixture was stirred and dissolved.

In a separate reactor, exo-NBL (2.50 g, 16.7 mmol) of Synthesis Example 2 was added, a three-way cock was installed to perform nitrogen substitution, and dry dichloromethane (33 mL) was added as a solvent to prepare a monomer solution. The monomer solution was taken out with a syringe, added to the catalyst solution cooled to -20°C, and stirred for 4 hours. Polymerization was stopped by adding a small amount of ethyl vinyl ether and stirring at room temperature for 30 minutes.

Thereafter, the solid obtained by reprecipitation in methanol was dried under heating and reduced pressure to obtain 2.44 g of a white powder cycloolefin polymer (poly(exo-NBL)).

2.41 g of poly(exo-NBL) and dry o-xylene (120 mL) were added to a glass container and stirred to dissolve. Thereafter, a small amount of dibutylhydroxytoluene (BHT) and RuHCl(CO)(PPh ₃ ) ₃ (144 mg, 0.15 mol) were added, and the container was transferred to a stainless steel autoclave and sealed.

The inside of the reaction vessel was replaced with hydrogen (0.8 MPa), and the mixture was stirred for 6 hours at an oil bath temperature of 135°C. After the reaction, the temperature was returned to room temperature, and the polymerization solution was precipitated in methanol to obtain a polymer, which was dried under heat and reduced pressure. The obtained polymer was hydrogenated twice under the same conditions to obtain a cycloolefin polymer (H-poly(exo-NBL) with a conversion rate of 98% and a yield of 2.18 g, yield of 90%. ) was obtained.

The Mw of the polymer was 36,000.

A test piece was prepared in the same manner as in Example 1, and various physical properties were evaluated.

[Comparative example 1]
Using ZEONEX (Tg 143°C) as a lactone-free cycloolefin polymer, it was heated to a temperature 20°C to 40°C higher than the glass transition temperature Tg of the resin using a vacuum heating press machine (Model 11FD manufactured by Imoto Seisakusho Co., Ltd.). Then, vacuum pressure was applied for 10 minutes under a pressure of 5 MPa.

Thereafter, it was cooled to prepare test pieces for birefringence evaluation and contact angle evaluation, and various physical properties were evaluated.

[Comparative example 2]
Using ARTON (Tg 164°C) as a lactone-free cycloolefin polymer, a test piece was prepared in the same manner as in Comparative Example 2, and various physical properties were evaluated.

[Evaluation results]
Table 1 shows the physical properties of the polymer obtained above.

As is clear from Table 1, the cycloolefin polymer having a lactone structure of the present invention was shown to be a polymer that has both low birefringence and excellent surface processability (contact angle, wettability).

The cycloolefin polymer containing a lactone structure of the present invention has low birefringence and excellent surface processability.

The cycloolefin polymer containing a lactone structure of the present invention has excellent imaging performance and excellent adhesion with other materials, and can be suitably used for optical lenses. It has excellent adhesion with other materials and can be suitably used for optical films.

Claims (6)

A cycloolefin polymer containing a structural unit represented by the following general formula (1).

(In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.) The cycloolefin polymer according to claim 1, wherein in the general formula (1), R ¹ to R ⁸ are hydrogen. A molded article comprising the cycloolefin polymer according to claim 1 or 2. The molded article according to claim 3, which is an optical film or an optical lens. A method for producing a cycloolefin polymer, the method comprising:
(1) 4-oxa-endo-tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (endo-NBL) or 4-oxa-exo in the presence of a third generation Grubbs catalyst in a solvent -tricyclo[5.2.1.0 ^2,6 ]dec-8-en-3-one (exo-NBL), including a step of ring-opening polymerization reaction,
A method for producing an H-poly(endo-NBL) cycloolefin polymer or an H-poly(exo-NBL) cycloolefin polymer containing a structural unit represented by the following general formula (1).

(In formula (1), R ¹ to R ⁸ are each independently the same or different and represent a substituent.) Furthermore, (2) in a solvent and in the presence of a hydrogenation catalyst, the H-poly(endo-NBL) cycloolefin polymer or H-poly(exo-NBL) cycloolefin polymer obtained in step (1) is treated with hydrogen. Including the step of chemical reaction,
A method for producing a cycloolefin polymer according to claim 5.