Hydrogenated cycloolefin polymer having high adhesion and high elongation and method for preparing the same

Abstract

The application relates to the technical field of high polymer materials, in particular to a hydrogenated cycloolefin polymer with high adhesion and high elongation and a preparation method thereof. The method comprises the following steps: performing a ROMP polymerization reaction on norbornadiene and a second cycloolefin in the presence of a solvent, a polymerization catalyst and a molecular weight regulator, obtaining a cycloolefin polymer solution after quenching; adding an oxidizing agent into the cycloolefin polymer solution to perform an opening ring oxidation reaction, and obtaining an intermediate after post-treatment; performing a hydrogenation reaction on the intermediate and hydrogen in the presence of a hydrogenation catalyst to obtain the hydrogenated cycloolefin polymer. The hydrogenated cycloolefin polymer provided by the application has higher elongation than conventional cycloolefin polymers, and has higher adhesion to glass and metal substrates.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a hydrogenated cyclic olefin polymer with high adhesion and high elongation and its preparation method. Background Technology

[0002] Cyclic olefin polymers, a class of polymeric materials produced by ring-opening metathesis polymerization (ROMP) of cyclic olefin monomers, have become core substrates in optical thin films, optical lenses, and electronic packaging due to their excellent optical transparency, low birefringence, chemical corrosion resistance, and dimensional stability. They are widely used in display devices, optoelectronic equipment, and other industries. However, traditional cyclic olefin polymers still have two major drawbacks: first, they have poor interfacial adhesion to commonly used substrates such as glass and metals, making it difficult to meet the bonding requirements of optical bonding and electronic packaging; second, they lack flexibility, failing to adapt to the application needs of flexible displays, wearable devices, and other fields, becoming a key bottleneck for their application expansion.

[0003] To improve the performance of cyclic olefin polymers, numerous process optimization studies have been conducted in the prior art. For example, Chinese invention patent application CN120040662A discloses a two-step polymerization method for preparing cyclic olefin polymers. By controlling the viscosity of the prepolymer at 25°C within the range of 3-300 cps, the tensile strength, tensile modulus, and film thickness uniformity of the product are significantly improved, and the processing performance and mechanical properties of the cyclic olefin polymer are optimized to a certain extent. However, this method only improves the processing and basic mechanical properties of the material through polymerization process control. The product still retains the problem of poor adhesion to glass and metal substrates of traditional COP, and cannot meet the actual needs of optical bonding and encapsulation. At the same time, this method cannot improve the flexibility of the material at the molecular level, and the effect of improving the elongation at break is limited. Moreover, its process has strict requirements for the control of prepolymer viscosity, and in industrial production, even small fluctuations in viscosity can easily lead to unstable product performance. Furthermore, it does not solve the problems of low monomer activity and poor catalyst system compatibility in cyclic olefin polymerization, and thus fails to achieve dual optimization of performance and preparation process.

[0004] In summary, there is an urgent need to develop a hydrogenated cyclic olefin polymer and its preparation method that combines high adhesion and high elongation, with a simple preparation process, low catalyst cost, and suitability for industrial production, in order to overcome the above-mentioned shortcomings of existing technologies and promote the further application of cyclic olefin polymers in high-end optoelectronic fields. Summary of the Invention

[0005] The first aspect of this invention provides a method for preparing a hydrogenated cyclic olefin polymer with high adhesion and high elongation, comprising the following steps: performing ROMP polymerization on norbornene and a second cyclic olefin in the presence of a solvent, a polymerization catalyst, and a molecular weight regulator, and obtaining a cyclic olefin polymer solution after quenching; adding an oxidant to the cyclic olefin polymer solution to perform a ring-opening oxidation reaction, and obtaining an intermediate after post-treatment; and performing a hydrogenation reaction on the intermediate with hydrogen in the presence of a hydrogenation catalyst to obtain the hydrogenated cyclic olefin polymer.

[0006] In existing technologies, polar groups such as carboxyl groups are typically introduced during the ROMP polymerization stage of cyclic olefin polymers. This significantly negatively impacts the polymerization reaction, interfering with catalyst activity and reducing monomer conversion. Traditional methods, relying solely on adjusting polymerization process parameters, cannot address the core defects of cyclic olefin polymers, such as poor adhesion to glass and metal substrates and insufficient flexibility, at the molecular level. Consequently, the elongation at break and interfacial adhesion of the finished product fail to meet the application requirements of high-end optoelectronic fields. This invention employs a stepwise modification strategy, first using norbornene and a second cyclic olefin as monomers to complete the ROMP polymerization reaction under the synergistic effect of solvent, polymerization catalyst, and molecular weight regulator. Because no polar groups are introduced, this process effectively ensures the polymerization... The high conversion rate of the reaction, after quenching, yields a well-structured cyclic olefin polymer. Then, a ring-opening oxidation reaction precisely introduces polar carboxyl groups into the polymer molecular chain. These carboxyl groups can form hydrogen bonds or coordination bonds with hydroxyl groups and metal ions on the surface of glass and metal substrates, enhancing interfacial adhesion at the intermolecular interaction level. Simultaneously, the open-ring structure of the molecular chain increases the space for chain segment movement, improving the material's flexibility and elongation at break. Finally, a hydrogenation reaction saturates the unsaturated bonds in the polymer molecular chain, retaining the high adhesion advantage brought by the carboxyl groups while further optimizing the material's structural stability. Ultimately, this achieves a synergistic improvement in the high conversion rate preparation and high adhesion and elongation properties of the hydrogenated cyclic olefin polymer.

[0007] The second cyclic olefin includes one or more of norbornene and its derivatives.

[0008] The norbornene and its derivatives include one or more of norbornene (NB), bridged methylene tetrahydrofluorene (MTF), tetracyclododecene (TCD), methyl norbornene, and vinyl norbornene.

[0009] The molar ratio of norbornene to the second cyclic olefin monomer is (3-5):(6-10).

[0010] The ROMP polymerization reaction includes: mixing uniformly at 25-40℃, and then heating to 50-75℃ for 1-3 hours.

[0011] Optionally, the molar ratio of norbornene to the second cyclic olefin monomer is (4-5):(6-10).

[0012] The solvent includes one of cyclohexane, toluene, and xylene, and the concentration of norbornene and the second cyclic olefin is 10-20 wt%.

[0013] The polymerization catalyst includes a main catalyst, a co-catalyst, and a reaction regulator.

[0014] The main catalyst is one or more of high-valence transition metal chlorides; the co-catalyst is one or more of alkylaluminum compounds; and the reaction regulator is one or more of phenols, alcohols, ethers, and esters.

[0015] The main catalyst includes one or more of tungsten hexachloride, tungsten pentachloride, titanium tetrachloride, molybdenum tetrachloride, and rhenium pentachloride, and is used in an amount of 0.01-0.1% of the total molar amount of the monomers (the sum of norbornene and the second cyclic olefin); the co-catalyst includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-n-butylaluminum, and is used in an amount of 0.01-0.1% of the total molar amount of the monomers; the reaction regulator includes one or more of p-tert-butylcatechol, p-tert-butylphenol, propanol, butanol, dibutyl ether, diphenyl ether, ethyl acetate, benzyl acetate, and ethyl benzoate, and is used in an amount of 0.01-0.1% of the total molar amount of the monomers.

[0016] The molecular weight regulator includes a monoolefin compound selected from at least one of ethylene, propylene, 1-hexene, 1-octene, and styrene, and is used in an amount of 0.5-2.0% of the total molar amount of the monomer.

[0017] After the ROMP polymerization reaction is quenched by adding an alcohol quencher, a cyclic olefin polymer solution is obtained.

[0018] The alcohol quencher is selected from at least one of methanol, ethanol, and isopropanol, and is used in an amount 5-10 times the molar amount of the main catalyst.

[0019] The oxidant is selected from at least one of potassium permanganate, hydrogen peroxide / sodium tungstate system, and peracetic acid, and the amount of the oxidant used is 5-20% of the mass of the cyclic olefin polymer.

[0020] The ring-opening oxidation reaction takes 2-8 hours and is carried out at a temperature of 30-80℃.

[0021] The ring-opening oxidation reaction is detected by infrared spectroscopy, and the amount of ring-opening oxidation is calculated by acid value titration, with the acid value controlled between 5-25 mg KOH / g.

[0022] The post-treatment includes adding a reducing agent to reduce excess oxidant. The reducing agent is selected from at least one of oxalic acid and sodium bisulfite, and the amount used is 10-30% of the mass of the oxidant.

[0023] The hydrogenation catalyst is selected from at least one of Pd / C (palladium / carbon), Pt / C (platinum / carbon), Rh / C (rhodium / carbon), and supported nickel, and is used in an amount of 1-3% of the mass of the oxidized cyclic olefin polymer.

[0024] The hydrogenation reaction further includes a solvent selected from at least one of cyclohexane and tetrahydrofuran, wherein the concentration of the oxidized cycloolefin polymer is 50-150 g / L.

[0025] The conditions for the hydrogenation reaction include: reacting at 80-180℃ and 3-6MPa for 1-4 hours.

[0026] Optionally, the hydrogenation reaction conditions include: reacting at 120-180℃ and 4-5MPa for 2-3 hours.

[0027] The hydrogenation reaction includes a post-treatment process, which includes filtering the catalyst. The specific method includes: vacuum filtration or pressure filtration, and after filtration, the filtrate is poured into an alcohol to precipitate and obtain the hydrogenated cyclic olefin polymer.

[0028] A second aspect of the present invention provides a hydrogenated cyclic olefin polymer with high adhesion and high elongation, which is prepared by the above-described preparation method.

[0029] Beneficial effects 1. This invention uses norbornene and a second cyclic olefin to generate a cyclic olefin polymer via ROMP reaction, followed by oxidative ring-opening to introduce carboxyl groups, and finally hydrogenation treatment. This avoids the negative impact of polar groups on the ROMP reaction in traditional methods, achieving high conversion rate and significantly improving adhesion and elongation to glass substrates.

[0030] 2. By limiting the second cyclic olefin to include one or more of norbornene and its derivatives, and the molar ratio of norbornene to the second cyclic olefin monomer is (3-5):(6-10), the elongation at break of the polymer can be further improved to ≥90% while maintaining the light transmittance (≥90%).

[0031] 3. By limiting the polymerization catalyst to include the main catalyst, co-catalyst, and reaction regulator, and using high-valent chlorides such as tungsten hexachloride and tungsten pentachloride as the main catalyst, combined with alkylaluminum co-catalyst and reaction regulator, the polymerization conversion rate can be increased to >99% and the cost can be reduced, thus meeting the needs of industrial production.

[0032] 4. By limiting the ring-opening oxidation reaction time to 2-8 hours and the temperature to 30-80℃, the adhesion to glass or stainless steel plates can be further improved.

[0033] 5. The preparation method of this invention is simple and has a high polymerization conversion rate. Attached Figure Description

[0034] Figure 1 The infrared spectra of the hydrogenated cyclic olefin polymer (purple), cyclic olefin polymer (green), and intermediate (red) of Example 1 are shown; the hydrogenated cyclic olefin polymer (blue) of Comparative Example 1 is shown. Detailed Implementation

[0035] Example 1 A method for preparing a hydrogenated cyclic olefin polymer with high adhesion and high elongation comprises the following steps (all parts are parts by weight, wherein the polymerization catalyst consists of a main catalyst, a co-catalyst, and a reaction regulator): Step 1: In a dry, nitrogen-replacement polymerization reactor, add monomers consisting of 20 parts norbornene, 40 parts TCD and 40 parts MTF, and simultaneously add 500 parts dehydrated cyclohexane as solvent, 0.6 parts 1-octene as molecular weight regulator, 0.2 parts dibutyl ether and 0.18 parts isopropanol as reaction regulators, and 0.48 parts triisobutylaluminum as co-catalyst. Stir at 40°C for 10 min, and add 45 parts toluene solution (0.6 wt% of the total monomer content) of the main catalyst (tungsten hexachloride) dropwise over 30 min. After stirring evenly, raise the temperature to 60°C and react for 2 h. After the monomer conversion rate (determined by gas chromatography) is >99%, quench with 3-5 parts ethanol to obtain the cyclic olefin polymer solution.

[0036] Step 2: Add an oxidant (0.1 mol / L alkaline potassium permanganate aqueous solution) to the cyclic olefin polymer solution. The amount of oxidant is 10% of the mass of the cyclic olefin polymer. Ring-opening oxidation is carried out by stirring at 50℃ for 2 hours. The characteristic absorption peak of the carboxyl group is detected by infrared spectroscopy. The amount of ring-opening oxidation is calculated by acid value titration. When the acid value is 10 mg KOH / g, oxalic acid is added to reduce the excess oxidant. The amount of oxalic acid is 20% of the mass of the oxidant. The mixture is washed with water until the pH of the aqueous phase is 6-7, and this is used as an intermediate.

[0037] Step 3: After drying and dehydrating the intermediate, take 10 parts and add them to a high-pressure hydrogenation reactor. Then add 90 parts of cyclohexane to dissolve it, and simultaneously add 0.5 parts of a supported nickel hydrogenation catalyst (Shanghai Xunkai Catalysis's 8800 supported nickel catalyst). Heat to 170℃ and react for 4 hours under a 3.5MPa hydrogen atmosphere. Cool and filter to obtain a colorless, clear liquid, which is a hydrogenated cycloolefin polymer, such as... Figure 1 As shown, the hydrogenation rate was >99.5% as measured by infrared spectroscopy.

[0038] Example 2 The specific implementation method is the same as in Example 1; the difference is that in step 2: an oxidant (20wt% hydrogen peroxide / 5wt% sodium tungstate / water system) is added to the cyclic olefin polymer solution, and the amount of oxidant is 15% of the mass of the cyclic olefin polymer. Ring-opening oxidation is carried out by stirring at 60°C for 3 hours. The characteristic absorption peak of the carboxyl group is detected by infrared spectroscopy, and the amount of ring-opening oxidation is calculated by acid value titration. When the acid value is 15 mg KOH / g, sodium bisulfite is added to reduce the excess oxidant, and the amount of sodium bisulfite is 25% of the mass of the oxidant. The mixture is washed with water until the pH of the aqueous phase is 6~7, which is then used as an intermediate.

[0039] Example 3 The specific implementation method is the same as in Example 1; the difference is that in step 2: an oxidant (peracetic acid) is added to the cyclic olefin polymer solution, the amount of oxidant being 20% ​​of the mass of the cyclic olefin polymer, and ring-opening oxidation is carried out by stirring at 70°C for 4 hours. The characteristic absorption peak of the carboxyl group is detected by infrared spectroscopy, and the amount of ring-opening oxidation is calculated by acid value titration. When the acid value is 20 mg KOH / g, oxalic acid is added to reduce the excess oxidant, the amount of oxalic acid being 30% of the mass of the oxidant, and the mixture is washed with water until the pH of the aqueous phase is 6~7, which is then used as an intermediate.

[0040] Example 4 The specific implementation method is the same as in Example 1; the difference is that, by weight, the monomer is 30 parts norbornene and 70 parts second cyclic olefin (40 parts TCD and 30 parts MTF).

[0041] Example 5 The specific implementation method is the same as in Example 1; the difference is that the reaction time for ring-opening oxidation is 4 hours.

[0042] Example 6 The specific implementation method is the same as in Example 1; the difference is that 0.5 parts of hydrogenation catalyst are replaced with 0.25 parts of Pt / C hydrogenation catalyst.

[0043] Example 7 The specific implementation method is the same as in Example 1; the difference is that the reaction time for ring-opening oxidation is 4 hours.

[0044] Comparative Example 1 A method for preparing a hydrogenated cyclic olefin polymer comprises the following steps (all parts are by weight, wherein the polymerization catalyst consists of a main catalyst, a co-catalyst, and a reaction regulator): Step 1: In a dry, nitrogen-replacement polymerization reactor, add monomers consisting of 20 parts norbornene, 40 parts TCD and 40 parts MTF, and simultaneously add 500 parts dehydrated cyclohexane as solvent, 0.6 parts 1-octene as molecular weight regulator, 0.2 parts dibutyl ether and 0.18 parts isopropanol as reaction regulators, and 0.48 parts triisobutylaluminum as co-catalyst. Stir at 40°C for 10 min, and add 45 parts toluene solution (0.6 wt% of the total monomer content) of the main catalyst (tungsten hexachloride) dropwise over 30 min. After stirring evenly, raise the temperature to 60°C and react for 2 h. After the monomer conversion rate (determined by gas chromatography) is >99%, quench with 3-5 parts ethanol to obtain the cyclic olefin polymer solution.

[0045] Step 2: After drying the cyclic olefin polymer solution, take 10 parts and add them to a high-pressure hydrogenation reactor. Then add 90 parts of cyclohexane to dissolve it, and add 0.5 parts of supported nickel hydrogenation catalyst (Shanghai Xunkai Catalysis' 8800 supported nickel catalyst). Heat to 170℃ and react for 4 hours under a 3.5MPa hydrogen atmosphere. Cool down and filter to obtain a colorless clear liquid, which is the hydrogenated cyclic olefin polymer.

[0046] Comparative Example 2 The specific implementation method is the same as Comparative Example 1; the difference is that, by weight, the monomer is 30 parts norbornene and 70 parts second cyclic olefin (40 parts TCD and 30 parts MTF).

[0047] Performance testing methods and data The hydrogenated cyclic olefin polymers obtained in Examples 1-7 and Comparative Examples 1-2 were subjected to performance tests, and the test data are listed in Table 1.

[0048] 1. Light transmittance test: Refer to GB / T2410-2008 for the determination of light transmittance and haze of transparent plastics.

[0049] 2. Adhesion Test: Refer to ASTM D3359, "Standard Test Method for Coating Adhesion," and the specific steps are as follows: Sample preparation: The hydrogenated cycloolefin polymer was dissolved in cyclohexane to prepare a 10% wt solution. Using a wire-bar coating machine, the solution was applied to the surfaces of glass and stainless steel plates with an area of ​​20 × 20 cm, and then thoroughly dried at 80°C to form a thin film with a thickness of 80 μm. From the surface of the substrate coated with the polymer film, a 10 × 10 cm section was taken from the center and cut into 10 rows and 10 columns of 1 × 1 cm squares using a utility knife.

[0050] Test: After applying adhesive tape to the surface of the film, peel it off perpendicular to the plane and count the number of squares left on the substrate surface. The more squares left, the stronger the adhesion.

[0051] 3. Mechanical performance testing: Tested according to standard GB / T1701-2001.

[0052] 4. Acid value test: Dissolve the sample in toluene to prepare a 10%wt solution, and titrate with a 0.05mol / L potassium hydroxide toluene-ethanol mixed solution. The mass ratio of toluene to ethanol is 7:3. Use phenolphthalein as an indicator and titrate until the solution turns pink and remains pink for 30 seconds as the endpoint.

[0053] Table 1

[0054] The data in Table 1 shows that conventional cyclic olefin polymers (Comparative Examples 1 and 2) have poor adhesion to glass or stainless steel substrates. However, after introducing carboxyl groups through oxidative ring-opening in the examples, the adhesion to glass or stainless steel substrates is greatly improved. A comparison of the data from Examples 1 to 3 shows that the deeper the degree of oxidative ring-opening, the greater the amount of carboxyl groups introduced, and the higher the acid value. In these cases, the adhesion to glass or stainless steel substrates is also better, and the higher the degree of ring-opening, the higher the elongation of the product. A comparison of the data from Examples 1 and 6 shows that the Pt / C hydrogenation catalyst can be used to replace the 8800 supported nickel catalyst from Shanghai Xunkai Catalysis with little impact on product performance.

Claims

1. A method for preparing a hydrogenated cyclic olefin polymer with high adhesion and high elongation, characterized in that, Includes the following steps: Norbornene and a second cyclic olefin were subjected to ROMP polymerization in the presence of a solvent, a polymerization catalyst, and a molecular weight regulator. After quenching, a cyclic olefin polymer solution was obtained. An oxidant was added to the cyclic olefin polymer solution to carry out a ring-opening oxidation reaction, and an intermediate was obtained after post-treatment. The intermediate was hydrogenated with hydrogen in the presence of a hydrogenation catalyst to obtain a hydrogenated cyclic olefin polymer.

2. The preparation method according to claim 1, characterized in that, The second cyclic olefin includes one or more of norbornene and its derivatives.

3. The preparation method according to claim 2, characterized in that, The norbornene and its derivatives include one or more of norbornene, bridged methylene tetrahydrofluorene, tetracyclododecene, methyl norbornene, and vinyl norbornene.

4. The preparation method according to claim 1 or 3, characterized in that, The molar ratio of norbornene to the second cyclic olefin monomer is (3-5):(6-10).

5. The preparation method according to claim 1, characterized in that, The ROMP polymerization reaction includes: mixing uniformly at 25-40℃, and then heating to 50-75℃ for 1-3 hours.

6. The preparation method according to claim 5, characterized in that, The polymerization catalyst includes a main catalyst, a co-catalyst, and a reaction regulator; the main catalyst includes one or more of tungsten hexachloride, tungsten pentachloride, titanium tetrachloride, molybdenum tetrachloride, and rhenium pentachloride; the co-catalyst includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-n-butylaluminum; and the reaction regulator includes one or more of p-tert-butylcatechol, p-tert-butylphenol, propanol, butanol, dibutyl ether, diphenyl ether, ethyl acetate, benzyl acetate, and ethyl benzoate.

7. The preparation method according to claim 1, characterized in that, The oxidant is selected from at least one of potassium permanganate, hydrogen peroxide / sodium tungstate system, and peracetic acid.

8. The preparation method according to claim 1, characterized in that, The ring-opening oxidation reaction takes 2-8 hours and is carried out at a temperature of 30-80℃.

9. The preparation method according to claim 1, characterized in that, The conditions for the hydrogenation reaction include: reacting at 80-180℃ and 3-6MPa for 1-4 hours.

10. A hydrogenated cyclic olefin polymer with high adhesion and high elongation, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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