Cycloolefin copolymers and curable compositions

Abstract

The present invention provides a cured product of a cycloolefin copolymer that possesses high processability, heat resistance, dielectric properties, toughness, and flame retardancy. [Solution] A cycloolefin copolymer represented by formula (I-1) or formula (I-2) and a curable composition are provided. JPEG0007912109000034.jpg48169

Description

Technical Field

[0001] The present invention relates to a cycloolefin copolymer, and particularly to a cycloolefin copolymer having a phosphorus-containing flame retardant group in the molecule. The present invention also relates to a curable composition.

Background Art

[0002] Norbornene is an unsaturated cycloolefin compound. As shown in Chemical Formula 1, norbornene is obtained by a Diels-Alder reaction of cyclopentadiene, which is a by-product of petroleum cracking, and ethylene.

Chem.

[0003] Norbornene forms a cycloolefin copolymer (COP) by ring-opening metathesis polymerization (ROMP). Its chemical structure and reaction mechanism are shown in Chemical Formula 2 below.

Chem.

[0004] A cycloolefin copolymer (COP) exhibits excellent chemical resistance, high optical transparency, low moisture absorption, low dielectric constant, etc. due to the saturated aliphatic groups contained in its structure and the rigid cyclic structure. However, because its structure contains many aliphatic groups, its glass transition temperature is low (Tg < 80°C).

[0005] To improve the thermal properties of cycloolefin polymers (COPs), the material may be made flame-retardant by a thermal crosslinking reaction. In the development of flame-retardant materials, halogen-based flame retardants were previously used, but because they release highly toxic substances harmful to health during combustion, phosphorus-based flame retardants are now used. [Overview of the project] [Problems that the invention aims to solve]

[0006] Based on the above, it appears that there is still room for improvement in conventional cycloolefin polymers. According to the present invention, by introducing a phosphorus-containing structure, the cycloolefin polymer does not produce toxic substances during combustion and can be made to have excellent flame retardancy. [Means for solving the problem]

[0007] To achieve the above-mentioned and other objectives, the present invention provides a cycloolefin copolymer having a structure represented by formula (I-1) or formula (I-2). [ka] [In equations (I-1) and (I-2), R1 is, [ka] or [ka] R2 represents a hydrogen group, halogen, or C1-C6 alkyl group. R3 and R4 are each independently selected from the group consisting of a hydrogen group, C1-C6 alkyl group, phenyl group, and CF3 group, where n is a natural number between 5 and 200, and m is a natural number between 5 and 200.

[0008] In the embodiments of the present invention, the cycloolefin copolymer has a structure represented by formula (II). [Chemical formula]

[0009] In an embodiment of the present invention, the cycloolefin copolymer has a structure represented by formula (III). [Chemical formula]

[0010] In an embodiment of the present invention, the cycloolefin copolymer has a structure represented by formula (IV). [Chemical formula]

[0011] In an embodiment of the present invention, the cycloolefin copolymer has a structure represented by formula (V). [[ID=·29]] [Chemical formula]

[0012] To achieve the above object and other objects, the present invention further provides a curable composition comprising the above cycloolefin copolymer and a curing accelerator.

[0013] In an embodiment of the present invention, the curing accelerator is selected from the group consisting of an imidazole-based curing accelerator, an amine-based curing accelerator, and an organic phosphorus-based curing accelerator.

[0014] In an embodiment of the present invention, the imidazole-based curing accelerator is selected from the group consisting of imidazole, 2-methylimidazole, and 2-methyl-4-ethylimidazole.

[0015] In the embodiments of the present invention, the amine-based curing accelerator is 4-dimethylaminopyridine (DMAP).

[0016] In the embodiments of the present invention, the organophosphorus curing accelerator is triphenylphosphine. [Effects of the Invention]

[0017] The cycloolefin copolymer according to the present invention, by introducing a phosphorus-containing structure, can provide a cured cycloolefin copolymer with high processability, heat resistance, dielectric properties, toughness, and flame retardancy.

[0018] The curable composition according to the present invention, by containing the above-mentioned cycloolefin copolymer, can provide the formed cured product with the above-mentioned excellent properties. [Brief explanation of the drawing]

[0019] To clarify the description of this invention, the thickness and dimensions of each layer in the drawings may be enlarged, omitted, or depicted schematically. Furthermore, the dimensions of each component do not necessarily correspond to the actual dimensions. [Figure 1] This is a diagram of the 1H-NMR spectrum of phosphorus monomer (1). [Figure 2] This is a diagram of the 1H-NMR spectrum of phosphorus monomer (2). [Figure 3] This is a diagram of the 1H-NMR spectrum of the functionalized phosphorus monomer (1). [Figure 4] This is a diagram of the 1H-NMR spectrum of the functionalized phosphorus monomer (2). [Figure 5] This is a diagram of the 1H-NMR spectrum of cycloolefin copolymer (1). [Figure 6] This is a diagram of the 1H-NMR spectrum of cycloolefin copolymer (2). [Figure 7]This is a diagram of the 1H-NMR spectrum of the cycloolefin copolymer (3). [Figure 8] This is a diagram of the 1H-NMR spectrum of saturated cycloolefin copolymer (3). [Figure 9] This is a diagram of the 1H-NMR spectrum of a functionalized saturated cycloolefin copolymer (1). [Figure 10] This is a diagram of the 1H-NMR spectrum of functionalized saturated cycloolefin copolymer (2). [Modes for carrying out the invention]

[0020] In order to fully understand the purpose, features, and effects of the present invention, the present invention will be described in detail below based on specific examples. The description is as follows.

[0021] The present invention provides a cycloolefin polymer (COP) containing a structure derived from norbornene. Specifically, the cycloolefin copolymer according to the present invention has a structure represented by formula (I-1) or formula (I-2). [ka] Also, R1 is [ka] or [ka] R2 is a hydrogen group, a halogen, or a C1-C6 alkyl group. R3 and R4 are independently selected from the group consisting of a hydrogen group, a C1-C6 alkyl group, a phenyl group, and a CF3 group, where n is a natural number from 5 to 200 and m is a natural number from 5 to 200.

[0022] [Method for preparing cycloolefin copolymers] A cycloolefin copolymer according to the present invention can be obtained by reacting a phosphorus-containing norbornene compound, norbornene, and a Grubbs catalyst. In this example, the molar ratio of the phosphorus-containing norbornene compound to norbornene may be, for example, 0.3 to 1.

[0023] In this embodiment, the reaction between the phosphorus-containing norbornene compound and norbornene is carried out in the presence of a single-component catalyst, mainly consisting of a transition metal and a carbene. Examples of such single-component catalysts include Schrock catalysts, Grubbs catalysts, or combinations thereof. The molar ratio of the single-component catalyst (mainly consisting of a transition metal and a carbene) to the phosphorus-containing norbornene compound may be, for example, 0.005 to 1.

[0024] Because the copolymer composition according to the present invention has a linear phosphorus-containing aliphatic structure, when the copolymer is used as a flame retardant for existing polyphenylene ether (PPE) resin compositions, the copolymer undergoes a crosslinking reaction with the PPE resin, improving the heat resistance and flame retardancy of the cured PPE resin without affecting the dielectric constant or loss tangent of the cured product.

[0025] [Copolymer composition] The above cycloolefin copolymer is mixed with a curing accelerator to form a copolymer composition.

[0026] In this example, the ratio of moles of the functionalized phosphorus monomer to norbornene in the cycloolefin copolymer may be 0.1 to 0.5. By blending the functionalized phosphorus monomer and norbornene in the above-mentioned ratio, a cured cycloolefin copolymer with high processability, heat resistance, dielectric properties, toughness, and flame retardancy can be obtained.

[0027] In this embodiment, the curing accelerator may be an imidazole-based curing accelerator, an amine-based curing accelerator, an organophosphorus-based curing accelerator, or a combination thereof. In this embodiment, the imidazole-based curing accelerator may be imidazole, 2-methylimidazole, or 2-methyl-4-ethylimidazole. The organophosphorus-based curing accelerator may be triphenylphosphine. The amine-based curing accelerator may be 4-dimethylaminopyridine (DMAP).

[0028] When using the aforementioned curing accelerator, the amount of the curing accelerator used is, for example, 0.1% to 1.0% by weight relative to the total weight of the copolymer composition.

[0029] In this embodiment, the cycloolefin copolymer according to the present invention can be further heat-cured to obtain a cured product of the cycloolefin copolymer having a crosslinked structure. The heat-curing temperature is, for example, 80°C to 220°C.

[0030] In this invention, a cycloolefin copolymer represented by formula (I-1) or formula (I-2) is used. Since the cycloolefin copolymer has a linear phosphorus-containing aliphatic structure, when the copolymer is used as a flame retardant in an existing PPE resin composition, the copolymer undergoes a crosslinking reaction with the PPE resin, and can improve the heat resistance and flame retardancy of the cured PPE resin without affecting the dielectric constant or loss tangent of the cured product.

[0031] The present invention will be further described below based on several embodiments, which are for illustrative purposes only and do not limit the scope of the present invention.

[0032] [Synthesis Example 1]

[0033] [Synthesis Example 1-1: Synthesis of phosphorus monomer (1)] [ka]

[0034] As shown in reaction equation 1 above, 21.6 g (0.1 mol) of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 13.6 g (0.1 mol) of 4-hydroxyacetophenone, and 37.3 g (0.4 mol) of aniline were placed in a reactor, the temperature was raised to 130°C, the reactants were completely dissolved, and the mixture was stirred uniformly. Then, 0.864 g (4 wt%) of p-toluenesulfonic acid (PTSA) (4 wt% of DOPO) was added to the reactor and the mixture was stirred at 130°C for 24 hours. After the reaction was complete, the mixture was precipitated with ethanol, washed three times, and then filtered by suction. The resulting filtration cake was dried in an oven at 80°C to obtain a pale yellow powder. The 1H-NMR spectrum is shown in Figure 1.

[0035] [Synthesis Example 1-2: Synthesis of Phosphorus Monomer (2)] [ka]

[0036] As shown in reaction equation 2 above, 13 g (0.03 mol) of phosphorus monomer (1), 5 g (0.03 mol) of 5-norbornene-2,3-dicarboxylic anhydride, and 30 mL of acetic acid were placed in a 500 mL three-necked flask and stirred. The mixture was heated to 100 °C while introducing nitrogen gas and reacted for 12 hours. The product was then filtered and recrystallized with EtOH. The resulting crystals were filtered and collected, and dried to obtain pale purple crystals. The ¹H-NMR spectrum is shown in Figure 2.

[0037] [Synthesis Example 2]

[0038] [Synthesis Example 2-1: Synthesis of Functionalized Phosphorus Monomer (1)] [ka]

[0039] As shown in reaction equation 3 above, 2.00 g (0.0035 mol) of phosphorus monomer (2), 0.7 g (0.0035 x 1.3 mmol) of methacrylic anhydride, 0.02 g (1 wt%) of 4-dimethylaminopyridine (DMAP) (NOR-DOPO), and 10 mL of N,N-dimethylacetamide (DMAc) were placed in a 100 mL three-necked flask and stirred. The mixture was heated to 45°C while introducing nitrogen gas and reacted for 12 hours. The mixture was then added dropwise to pure water to precipitate, filtered, and the resulting filtration cake was repeatedly washed with pure water and dried to obtain a white powder. Its 1H-NMR spectrum is shown in Figure 3.

[0040] [Synthesis Example 2-2: Synthesis of Functionalized Phosphorus Monomer (2)] [ka]

[0041] As shown in reaction equation 4 above, 2.00 g (0.0035 mol) of phosphorus monomer (2), 0.69 g (0.0035 x 1.3 mmol) of 4-vinylbenzyl chloride, 0.63 g of potassium carbonate (K2CO3), and 30 mL of N,N-dimethylacetamide (DMAc) were placed in a 100 mL three-necked flask and stirred. The temperature was raised to 80°C while introducing nitrogen gas, and the reaction was carried out for 12 hours. The mixture was then added dropwise to pure water to precipitate, and the filtered cake was washed repeatedly with pure water after suction filtration and dried to obtain a white powder. Its 1H-NMR spectrum is shown in Figure 4.

[0042] [Synthesis Example 3]

[0043] [Synthesis Example 3-1: Cycloolefin Copolymer (1)] [ka]

[0044] As shown in reaction equation 5 above, a solution of 1.06 g (0.0053 x 0.3 mol) of functionalized phosphorus monomer (1) and 5 mL of DMAc, and a solution of 0.02 g (0.5 mol%) of second-generation Grubbs catalyst and 2 mL of N,N-dimethylacetamide (DMAc) were placed in a reactor and stirred, and the reaction was carried out at room temperature for 1 hour while introducing nitrogen gas. Then, a solution of 0.5 g (0.0053 mol) of norbornene and 5 mL of DMAc was added to the reactor and the reaction was carried out for another 1 hour. Furthermore, 3 mL of ethyl vinyl ether (EVE) was added dropwise, and after 2 hours, the solution was precipitated and washed several times with methanol (MeOH), filtered by suction, and dried at room temperature to obtain a white solid. Its ¹H-NMR spectrum is shown in Figure 5.

[0045] [Synthesis Example 3-2: Cycloolefin Copolymer (2)] [ka]

[0046] As shown in reaction equation 6 above, a solution of 1.09 g (0.0053 x 0.3 mol) of functionalized phosphorus monomer (2) and 5 mL of N,N-dimethylacetamide (DMAc), and a solution of 0.02 g (0.5 mol%) of second-generation Grubbs catalyst and 2 mL of DMAc were placed in a reactor and stirred, and reacted at room temperature for 1 hour while introducing nitrogen gas. Then, a solution of 0.5 g (0.0053 mol) of norbornene and 5 mL of DMAc was added to the reactor and reacted for another hour. Subsequently, 3 mL of ethyl vinyl ether (EVE) was added dropwise, and after 2 hours, the mixture was precipitated and washed several times with methanol (MeOH), filtered by suction, and dried at room temperature to obtain a white solid. Its ¹H-NMR spectrum is shown in Figure 6.

[0047] [Synthesis Example 4]

[0048] [Synthesis Example 4-1: Cycloolefin Copolymer (3)] [ka]

[0049] As shown in reaction equation 7 above, a solution of 0.9 g (0.0053 x 0.3 mol) of phosphorus monomer (2) and 5 mL of N,N-dimethylacetamide (DMAc), and a solution of 0.02 g (0.5 mol%) of second-generation Grubbs catalyst and 2 mL of DMAc were placed in a reactor and stirred, and the reaction was carried out at room temperature for 1 hour while introducing nitrogen gas. Then, a solution of 0.5 g (0.0053 mol) of norbornene and 5 mL of DMAc was added to the reactor and the reaction was carried out for another hour. Subsequently, 3 mL of ethyl vinyl ether (EVE) was added dropwise, and after 2 hours, the mixture was precipitated and washed several times with methanol (MeOH), filtered by suction, and dried at room temperature to obtain a white solid. Its ¹H-NMR spectrum is shown in Figure 7.

[0050] [Synthesis Example 4-2: Saturated Cycloolefin Copolymer (3)] [ka]

[0051] As shown in reaction equation 8 above, a solution of 2 g of cycloolefin copolymer (3) and 30 mL of dimethylformamide (DMF), and 8 g of p-toluenesulfonyl hydrazide were placed in a 100 mL reactor and stirred, and reacted at 130 °C for 5 hours. After that, the mixture was precipitated and washed several times with methanol, filtered by suction, and vacuum dried at room temperature to obtain a yellow powder. Its ¹H-NMR spectrum is shown in Figure 8.

[0052] [Synthesis Example 4-3: Functionalized saturated cycloolefin copolymer (1)] [ka]

[0053] As shown in reaction equation 9 above, 2.00 g (0.0028 mol) of saturated cycloolefin copolymer (3), 0.4 g (0.0028 * 0.3 * 1.3 mmol) of methacrylic anhydride, 0.02 g (2 wt%) of 4-dimethylaminopyridine (DMAP) (2 wt% of NB-DOPO), and 10 mL of N,N-dimethylacetamide (DMAc) were placed in a 100 mL three-necked flask and stirred. The temperature was raised to 80°C while introducing nitrogen gas, and the reaction was carried out for 12 hours. The mixture was then reduced to methanol water to precipitate, and the filtered cake was washed repeatedly with methanol water to obtain a white powder. Its 1H-NMR spectrum is shown in Figure 9.

[0054] [Synthesis Example 5]

[0055] [Synthesis Example 5-1: Functionalized saturated cycloolefin copolymer (2)] [ka]

[0056] As shown in reaction equation 10 above, 2.00 g (0.0028 mol) of saturated cycloolefin copolymer (3) prepared in Synthesis Example 4-2, 0.4 g (0.0028 x 0.3 x 1.3 mmol) of 4-vinylbenzyl chloride, 0.075 g of potassium carbonate (K2CO3), and 30 mL of N,N-dimethylacetamide (DMAc) were placed in a 100 mL three-necked flask and stirred. The temperature was raised to 80°C while introducing nitrogen gas, and the reaction was carried out for 12 hours. Then, the mixture was added dropwise to methanol water to precipitate, and the filtered cake was washed repeatedly with methanol water after suction filtration and dried to obtain a white powder. Its 1H-NMR spectrum is shown in Figure 10.

[0057] [Test Example 1: Solubility Test of Copolymers] The solubility of cycloolefin copolymer (1), cycloolefin copolymer (2), cycloolefin copolymer (3), saturated cycloolefin copolymer (3), functionalized saturated cycloolefin copolymer (1), and functionalized saturated cycloolefin copolymer (2), synthesized in the above synthesis examples 3 to 5, in different solvents was evaluated by adding 5 mg of each to different solvents.

[0058] The results are shown in Table 1 below. It was confirmed that cycloolefin copolymer (1), cycloolefin copolymer (2), functionalized saturated cycloolefin copolymer (1), and functionalized saturated cycloolefin copolymer (2) are soluble in many common solvents. In other words, cycloolefin copolymer (1), cycloolefin copolymer (2), functionalized saturated cycloolefin copolymer (1), and functionalized saturated cycloolefin copolymer (2) contribute to the manufacturing process of copper foil laminates due to their high solubility.

[0059] [Table 1]

[0060] [Production of cured cycloolefin copolymers] The cured product comprising the cycloolefin copolymer according to the present invention can be produced, for example, by the following production examples 1 to 4.

[0061] [Manufacturing Example 1: Production of Cured Product 1 of Cycloolefin Copolymer] First, the cycloolefin copolymer (1) synthesized in Synthesis Example 3-1 was dissolved in a toluene-based solvent, and tert-butyl cumyl peroxide (TBCP) was added at a concentration of 10% by weight of the cycloolefin copolymer to obtain copolymer composition 1 with a solid content of 10% by weight.

[0062] The copolymer composition 1 was placed in an aluminum pan, and the aluminum pan containing the copolymer composition 1 was placed in a circulating oven and dried at 80°C for 8 hours to thoroughly remove the solvent. Then, the temperature was gradually increased to 120°C, 180°C, 200°C, and 220°C, each held for 2 hours, to cure the product. Next, the aluminum pan was immersed in an etching solution to separate the contents, thereby obtaining the cured cycloolefin copolymer 1.

[0063] [Manufacturing Example 2: Production of Cured Product 2 of Cycloolefin Copolymer] A cured cycloolefin copolymer 2 was prepared in the same manner as in Production Example 1, except that cycloolefin copolymer (2) synthesized in Synthesis Example 3-2 was used instead of cycloolefin copolymer (1) synthesized in Synthesis Example 3-1.

[0064] [Manufacturing Example 3: Production of Cured Product 1 of Saturated Cycloolefin Copolymer] A cured saturated cycloolefin copolymer 1 was prepared in the same manner as in Production Example 1, except that the functionalized saturated cycloolefin copolymer (1) synthesized in Synthesis Example 4-3 was used instead of the cycloolefin copolymer (1) synthesized in Synthesis Example 3-1.

[0065] [Manufacturing Example 4: Production of Cured Product 2 of Saturated Cycloolefin Copolymer] A cured saturated cycloolefin copolymer 2 was prepared in the same manner as in Production Example 1, except that the functionalized saturated cycloolefin copolymer (2) synthesized in Synthesis Example 5-1 was used instead of the cycloolefin copolymer (1) synthesized in Synthesis Example 3-1.

[0066] [Manufacturing Comparison Example 1: Manufacturing of Comparative Cured Product 1] Comparative cured product 1 was prepared in the same manner as in Production Example 1, except that a commercially available SA9000 product was used instead of the cycloolefin copolymer (1) synthesized in Synthesis Example 3-1.

[0067] [Manufacturing Comparison Example 2: Manufacturing of Comparative Cured Product 2] Comparative cured product 2 was prepared in the same manner as in Production Example 1, except that a commercially available OPE-2ST product was used instead of the cycloolefin copolymer (1) synthesized in Synthesis Example 3-1.

[0068] [Test Example 2: Evaluation of Thermal Properties, Dielectric Constant, and Flame Retardancy of Cured Cycloolefin Copolymers] The thermal properties and dielectric constants of cured cycloolefin copolymers 1 and 2, cured saturated cycloolefin copolymer 1 and cured saturated cycloolefin copolymer 2, and comparative cured products 1 and 2, produced in comparative examples 1 and 2, were evaluated using the method described below. The results are shown in Table 2.

[0069] (1) Glass transition temperature (Tg) The thermal glass transition temperature is measured by thermomechanical analysis (TMA). In thermomechanical analysis, the glass transition temperature of the sample is measured using a dynamic mechanical analyzer (DMA) (model: Perkin-Elmer Pyris Diamond) under conditions of a heating rate of 5°C / min.

[0070] Dynamic mechanical analysis (DMA) was performed on cured cycloolefin copolymer 1, cured cycloolefin copolymer 2, cured saturated cycloolefin copolymer 1, and cured saturated cycloolefin copolymer 2. The results are shown in Table 2.

[0071] (2) 5% weight loss temperature (Td5%) and coke retention rate The 5% weight loss temperature and the coke retention rate at 800°C of the sample are measured by thermogravimetric analysis (TGA). In thermogravimetric analysis, the weight change of the sample is measured using a thermogravimetric analyzer (model: Thermo Cahn VersaTherm) under conditions of a nitrogen atmosphere and a heating rate of 20°C / min. The 5% weight loss temperature is the temperature at which the weight of the sample decreases by 5%, and a higher 5% weight loss temperature indicates better thermal stability of the sample. The coke retention rate at 800°C is the percentage of the sample's remaining weight when the heating temperature reaches 800°C, and a higher percentage of the remaining weight at 800°C indicates better thermal stability of the sample.

[0072] (3) Dielectric constant (Dk) and loss tangent (Df) Under conditions of 25°C and 10GHz, the dielectric constant and loss tangent of the sample were measured using a ZNB20 steel rod / swatt manufactured by Rohde & Schwarz Taiwan.

[0073] [Table 2]

[0074] (4) Flame retardancy test In this experiment, following the UL94HB criteria, a 5in × 0.5in thin film was fixed vertically as a sample, and the sample was burned for 10 seconds with a ignition source directed upwards from below. After removing the ignition source, the continuous burning time was measured, and the presence or absence of drips onto the cotton wool below was observed. The results of this experiment are shown in Table 3.

[0075] [Table 3]

[0076] As shown in Table 2, thermogravimetric analysis (TGA) tests revealed that the 5% weight loss temperatures for cycloolefin copolymer cured product 1, cycloolefin copolymer cured product 2, saturated cycloolefin copolymer cured product 1, and saturated cycloolefin copolymer cured product 2, all composed of the cycloolefin copolymer according to the present invention, were 432°C, 423°C, 400°C, and 445°C, respectively. Furthermore, the coke residue rates for cycloolefin copolymer cured product 1, cycloolefin copolymer cured product 2, saturated cycloolefin copolymer cured product 1, and saturated cycloolefin copolymer cured product 2 were 3.4%, 14.3%, 5.5%, and 9.8%, respectively. These results confirm that the cured products composed of the cycloolefin copolymer according to the present invention possess excellent thermal stability (i.e., heat resistance).

[0077] Furthermore, evaluation of the dielectric properties of the cured cycloolefin copolymer revealed that the dielectric constants of cured cycloolefin copolymer 1, cured cycloolefin copolymer 2, cured saturated cycloolefin copolymer 1, and cured saturated cycloolefin copolymer 2, all made from the cycloolefin copolymer according to the present invention, are 2.2 to 2.6, and the loss loss tangent is 0.003 to 0.01. This low loss characteristic was confirmed to be equivalent to or better than that of conventional PPE resin cured products.

[0078] Furthermore, as shown in Table 3, cured cycloolefin copolymer 1, cured cycloolefin copolymer 2, cured saturated cycloolefin copolymer 1, and cured saturated cycloolefin copolymer 2, all composed of the cycloolefin copolymer according to the present invention, showed significantly superior flame retardancy in flame retardancy tests compared to commercially available OPE-2ST products. From these results, it was confirmed that cured products made from the cycloolefin copolymer according to the present invention possess excellent flame retardancy.

[0079] In summary, the cycloolefin copolymer according to the present invention has a linear phosphorus-containing aliphatic structure and, by undergoing a crosslinking reaction with polyphenylene ether (PPE) resin, can improve the heat resistance and flame retardancy of PPE resin cured products without affecting the dielectric constant or loss tangent of the cured product. Furthermore, cured products made from the cycloolefin copolymer composition according to the above examples possess high processability, heat resistance, dielectric properties, toughness, and flame retardancy.

[0080] Although the present invention has been described based on the above embodiments, it is not limited thereto, and various changes and modifications are possible without departing from its essence. Therefore, the scope of protection of the present invention should be in accordance with the claims described below.

Claims

1. A cycloolefin copolymer having a structure represented by formula (I-1) or formula (I-2). 【Chemistry 1】 [In equations (I-1) and (I-2), R １ teeth 【Chemistry 2】 or 【Transformation 3】 and R ２ is a hydrogen group, halogen or C １ to C ６ represents an alkyl group, R ３ and R ４ are each independently a hydrogen group, C １ to C ６ alkyl group, phenyl group and CF ３ group, n is a natural number from 5 to 200, and m is a natural number from 5 to 200]

2. A cycloolefin copolymer according to claim 1, having a structure represented by formula (II). 【Chemistry 4】

3. A cycloolefin copolymer according to claim 1, having a structure represented by formula (III). 【Transformation 5】

4. A cycloolefin copolymer according to claim 1, having a structure represented by formula (IV). 【Transformation 6】

5. A cycloolefin copolymer according to claim 1, having a structure represented by formula (V). 【Transformation 7】

6. A curable composition comprising the cycloolefin copolymer described in claim 1 and a curing accelerator.

7. The curable composition according to claim 6, wherein the curing accelerator is selected from the group consisting of imidazole-based curing accelerators, amine-based curing accelerators, and organophosphorus-based curing accelerators.

8. The curable composition according to claim 7, wherein the imidazole-based curing accelerator is selected from the group consisting of imidazole, 2-methylimidazole, and 2-methyl-4-ethylimidazole.

9. The curable composition according to claim 7, wherein the amine-based curing accelerator is 4-dimethylaminopyridine (DMAP).

10. The curable composition according to claim 7, wherein the organophosphorus curing accelerator is triphenylphosphine.

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