Low-temperature curing benzocyclobutenyl hydrocarbon resin as well as preparation method and application thereof

Abstract

The invention discloses low-temperature curing benzocyclobutenyl hydrocarbon resin as well as a preparation method and application thereof, and belongs to the technical field of electronic resin. The low-temperature curing benzocyclobutene hydrocarbon resin comprises a hydrocarbon resin main chain and an alkyl benzocyclobutene group, the hydrocarbon resin main chain has a plurality of alkyl groups or aralkyl groups; the alkyl benzocyclobutene group is grafted to at least one of a plurality of alkyl groups or aralkyl groups; the invention also discloses an application of the low-temperature curing benzocyclobutenyl hydrocarbon resin in preparation of a low-dielectric-loss copper-clad plate. The low-temperature curing benzocyclobutenyl hydrocarbon resin provided by the invention can be used for preparing a copper-clad plate at a relatively low process temperature, can provide excellent heat resistance, dimensional stability, dielectric property and the like, and can be applied to the field of high-frequency and high-speed copper-clad plates.

Description

Technical Field

[0001] This invention relates to the field of electronic resin synthesis technology, and in particular to a low-temperature curing benzocyclobutene-based hydrocarbon resin, its preparation method, and its application. Background Technology

[0002] With the rapid development of industries such as Artificial Intelligence Large Scale Integrated Circuits (AIGC), machine learning, 5G communication, millimeter-wave radar, and the Internet of Things, the frequency of signal transmission on printed circuit boards is increasing, making high-frequency, high-speed copper-clad laminates a research hotspot in the printed circuit board industry. To reduce transmission losses in high-frequency bands and meet the requirements of high-temperature soldering and multilayer assembly during substrate mounting, the insulating materials used in copper-clad laminates need to be halogen-free and flame-retardant, with better dielectric properties, heat resistance, glass transition temperature, and dimensional stability.

[0003] In recent years, hydrocarbon resins such as polybutadiene resin, styrene-butadiene copolymer, ethylene propylene diene copolymer, and cycloolefin copolymer have attracted much attention due to their low molecular chain polarity (electronegativity of carbon and hydrogen atoms are 2.5 and 2.1, respectively) and excellent dielectric properties (dielectric constant 2.4–2.8 at 1MHz, tanδ 0.0002–0.0006). However, these hydrocarbon resins have poor flame retardancy and extremely high chain segment flexibility, resulting in poor adhesion to the substrate. Copper-clad laminates made from them have insufficient flame retardancy and also suffer from poor heat resistance, low glass transition temperature, insufficient rigidity, and a large coefficient of thermal expansion.

[0004] In existing technologies, CN 117069877A, CN 117069878A, and CN 118256082A graft benzocyclobutene groups onto the side chains of hydrocarbon resins, significantly improving the heat resistance and mechanical properties of hydrocarbon resin-based copper clad laminates while maintaining the low dielectric and low dielectric loss characteristics of hydrocarbon resins. However, the benzocyclobutene structure has a high activation energy, requiring heating to 200°C or higher without an initiator. The benzocyclobutene four-membered ring undergoes square ring opening to form a highly reactive polymerizable intermediate, resulting in a high curing temperature, which affects the processing performance and process reliability of benzocyclobutene-based hydrocarbon resins. Summary of the Invention

[0005] This application aims to overcome the shortcomings of the prior art by providing a low-temperature curing benzocyclobutenyl hydrocarbon resin, its preparation method, and its applications. The low-temperature curing benzocyclobutenyl hydrocarbon resin of this invention has a benzocyclobutene structure linked to the hydrocarbon resin backbone via methylene groups. This enhances the electron-donating effect on the benzocyclobutenyl structure and reduces the activation energy of the benzocyclobutenyl group, thereby enabling the low-temperature curing benzocyclobutenyl hydrocarbon resin to cure at a lower temperature (≤168℃) without an initiator. It also exhibits excellent dimensional stability, high heat resistance, and low dielectric loss characteristics, making it suitable for use in the field of high-frequency, high-speed copper-clad laminates.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] Technical Solution 1: A low-temperature curing benzocyclobutene-based hydrocarbon resin, comprising a hydrocarbon resin backbone and alkylbenzocyclobutene groups; the hydrocarbon resin backbone has multiple alkyl or aralkyl groups; the alkylbenzocyclobutene groups are grafted onto at least one of the multiple alkyl or aralkyl groups.

[0008] As some possible embodiments of this application, the low-temperature curing benzocyclobutene-based hydrocarbon resin has the general chemical structural formula shown in (Ⅰ):

[0009]

[0010] Where x is any integer from 1 to 100, and y and z are any integers from 0 to 50;

[0011] R1, R2, R4, R7, R8, R9, R 10 R 11 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms;

[0012] R3 is selected from one or more of single bonds, alkyl groups containing 2 to 10 carbon atoms, and aralkyl groups containing 8 to 12 carbon atoms;

[0013] R5 is selected from benzocyclobutenyl-substituted methyl groups. It contains two or more alkyl groups with 2 to 10 carbon atoms and aralkyl groups with 8 to 12 carbon atoms, and must contain a benzocyclobutenyl-substituted methyl group.

[0014]

[0015] R6 is selected from hydrogen, phenyl, or benzocyclobutenyl-substituted methyl groups. One or more of alkyl groups containing 1 to 10 carbon atoms and aralkyl groups containing 7 to 12 carbon atoms.

[0016] As some possible embodiments of this application, the benzocyclobutenyl monosubstituted methyl group in the low-temperature curing benzocyclobutenyl hydrocarbon resin The molar percentage of the structural unit is 62% to 75%.

[0017] As some possible embodiments of this application, the general chemical structural formula of the hydrocarbon resin is shown in formula (II):

[0018]

[0019] Where k is any integer from 1 to 100, and j and n are any integers from 0 to 50;

[0020] R 12 R 14 R 15 R 17 R 18 R 19 R 20 R 21 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms;

[0021] R 13 It is an alkyl group containing one unsaturated bond and 2 to 10 carbon atoms, or an aralkyl group containing one unsaturated bond and 8 to 12 carbon atoms;

[0022] R 16 It is selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms.

[0023] As some possible embodiments of this application, the proportion of vinyl structure in the hydrocarbon resin is ≥50%, preferably 65% ​​to 90%.

[0024] Technical Solution Two:

[0025] A method for preparing a low-temperature curable benzocyclobutene-based hydrocarbon resin involves reacting a hydrocarbon resin with a halomethylbenzocyclobutene via a Heck reaction, followed by hydrogenation of the resulting benzocyclobutene-grafted hydrocarbon resin to completely eliminate any remaining double bonds in its structure, thereby obtaining the low-temperature curable benzocyclobutene-based hydrocarbon resin.

[0026] As some possible embodiments of this application, the preparation method of the low-temperature curing benzocyclobutene-based hydrocarbon resin specifically includes the following steps:

[0027] a. Preparation of benzocyclobutene-grafted hydrocarbon resin: Under anhydrous and inert gas conditions, weigh an appropriate amount of hydrocarbon resin into a reaction flask, add a measured amount of halomethylbenzocyclobutene, acid-binding agent, catalyst A, and solvent A, and maintain the reaction temperature at 70-100℃ to allow the hydrocarbon resin to react with halomethylbenzocyclobutene; monitor the degree of reaction by chromatography during the reaction to determine the reaction endpoint; after the reaction is completed, wash the reactants with water until neutral, filter, and distill under reduced pressure to obtain benzocyclobutene-grafted hydrocarbon resin.

[0028] b. Catalytic hydrogenation of benzocyclobutene-grafted hydrocarbon resin: The benzocyclobutene-grafted hydrocarbon resin from step a is dissolved in an appropriate amount of solvent B, and catalyst B with a mass fraction of 0.01% to 0.8% of the benzocyclobutene-grafted hydrocarbon resin is added. The mixture is stirred evenly, and an appropriate amount of hydrogen gas is introduced. The hydrogenation reaction is carried out at 20 to 100°C and a reaction pressure of 0.1 to 7 MPa for 1 to 10 hours. After the reaction is completed, the resin is filtered or washed with pure water and distilled under reduced pressure to obtain the low-temperature cured benzocyclobutene-based hydrocarbon resin.

[0029] As some possible embodiments of this application, the benzocyclobutene-grafted hydrocarbon resin has the general chemical structural formula shown in (III):

[0030]

[0031] Where g is any integer from 1 to 100, and m and f are any integers from 0 to 50;

[0032] R 22 R 24 R 26 R 28 R 29 R 30 R 31 R 32 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms;

[0033] R 23 It is selected from one or more of the following: single bond, alkyl group containing 2 to 10 carbon atoms, aralkyl group containing 8 to 12 carbon atoms, alkyl group containing 1 unsaturated bond and containing 2 to 10 carbon atoms, and aralkyl group containing 1 unsaturated bond and containing 8 to 12 carbon atoms;

[0034] R 25 Selected from benzocyclobutenyl monosubstituted methyl It contains two or more of the following: an alkyl group with one unsaturated bond and 2 to 10 carbon atoms, and an aralkyl group with one unsaturated bond and 8 to 12 carbon atoms, wherein it must contain a benzocyclobutenyl-substituted methyl group.

[0035] R 27 Selected from hydrogen, phenyl, benzocyclobutenyl monosubstituted methyl One or more of alkyl groups containing 1 to 10 carbon atoms and aralkyl groups containing 7 to 12 carbon atoms.

[0036] As some possible embodiments of this application, the molar ratio of the double bond of the halomethylbenzocyclobutene to the benzocyclobutene grafted hydrocarbon resin is (0.7-1):1; the molar ratio of the acid-binding agent to the halomethylbenzocyclobutene is (1-1.5):1.

[0037] As some possible embodiments of this application, the catalyst A is a mixture of a metal compound and a ligand; the molar ratio of the metal compound to the ligand is 1:(2.4~6.0), and the molar ratio of the metal compound to halomethylbenzocyclobutene is (2×10⁻⁶). -3 ~7×10 -3 ):1.

[0038] As some possible embodiments of this application, the catalyst B is a heterogeneous catalyst or a homogeneous catalyst. The heterogeneous catalyst includes, but is not limited to, nickel catalysts and transition metal catalysts supported on activated carbon, diatomaceous earth, alumina and other supports. The homogeneous catalyst includes, but is not limited to, aluminum / nickel catalytic systems, metallocene catalysts, platinum catalysts, rhodium catalysts and palladium catalysts.

[0039] As some possible implementations of this application, solvent A and solvent B are both non-polar solvents, including but not limited to toluene, xylene, cyclohexane, and n-hexane.

[0040] As some possible embodiments of this application, the halomethylbenzocyclobutene is selected from 4-bromomethylbenzocyclobutene, 4-chloromethylbenzocyclobutene, and 4-iodomethylbenzocyclobutene.

[0041] As some possible embodiments of this application, the acid-binding agent includes, but is not limited to, pyridine, triethylamine, trimethylamine, sodium bicarbonate, potassium bicarbonate, sodium carbonate, and potassium carbonate.

[0042] 3. Application of low-temperature curing benzocyclobutene-based hydrocarbon resin in the preparation of low-dissipation copper-clad laminates, wherein the preparation method of the low-dissipation copper-clad laminate is as follows:

[0043] S1. Mix 100 parts by weight of low-temperature curing benzocyclobutene hydrocarbon resin, 0.01% to 0.08% of the total resin mass of initiator, 25% to 53% of the total resin mass of filler and solvent evenly to prepare a resin solution. Place glass fiber in the resin solution for immersion and then remove it. Hang it at room temperature to remove most of the solvent, and then place it in an oven at 130℃ to 150℃ for baking for 5 to 10 minutes to obtain a low dielectric loss semi-cured sheet.

[0044] S2. Stack several layers of semi-cured sheets and attach copper foil to both sides. Place them in a hot press at a temperature of 150-160℃. Gradually increase the pressure to 0.2-4MPa depending on the adhesive flow. Press for 0.5-1h and then hot press at 155-175℃ for 4-8h. After natural cooling and depressurization, a low dielectric loss copper-clad laminate is obtained.

[0045] As some possible embodiments of this application, the initiator is any one of dicumyl peroxide (DCP), di-tert-butyl peroxide (DTBP), or tert-butyl peroxide (CP-01).

[0046] As some possible embodiments of this application, the filler is any one of silica, montmorillonite, magnesium oxide, aluminum oxide, mica powder, barium sulfate, and kaolin.

[0047] As some possible embodiments of this application, the solvent is any one of acetone, butanone, cyclohexanone, methyl isobutyl ketone, toluene, propylene glycol monomethyl ether, and propylene glycol methyl ether acetate.

[0048] As some possible implementations of this application, the fiberglass cloth model is selected from 1080E, 2116, 2313, 3313, and 7628.

[0049] As some possible implementations of this application, the number of layers of the semi-cured sheet is not limited and can be selected from any number of layers within the range achievable by the process.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] (1) The low-temperature curing benzocyclobutene-based hydrocarbon resin of the present invention is obtained by using halomethylbenzocyclobutene as a grafting modifier and undergoing Heck reaction and hydrogenation reaction with hydrocarbon resin. In the low-temperature curing benzocyclobutene-based hydrocarbon resin of the present invention, the benzocyclobutene structure is connected to the hydrocarbon resin backbone through methylene groups, which can enhance the electron-donating effect on the benzocyclobutene structure and reduce the activation energy of the benzocyclobutene group. This allows the low-temperature curing benzocyclobutene-based hydrocarbon resin to achieve curing at a lower temperature (≤168℃) without an initiator. Compared with hydrocarbon resins grafted with 4-halobenzocyclobutene (such as 4-bromobenzocyclobutene), its curing temperature is reduced by more than 30℃, and it has good processability and reliable process stability.

[0052] (2) The low-temperature curing benzocyclobutene-based hydrocarbon resin of the present invention enhances the rigidity of the molecular backbone, increases the crosslinking density of the hydrocarbon resin cured product, and thus improves the heat resistance, mechanical strength and dimensional stability of the hydrocarbon resin cured product.

[0053] (3) The low-temperature curing benzocyclobutene-based hydrocarbon resin of this invention has a benzocyclobutene group as the structural unit with a molar percentage of 62%–75%. This can compensate for the influence of the alkyl linkage structure introduced by halomethylbenzocyclobutene on heat resistance and mechanical properties, giving the low-temperature curing benzocyclobutene-based hydrocarbon resin excellent heat resistance, mechanical strength, and dimensional stability. If the molar percentage is too low, the low-temperature curing benzocyclobutene-based hydrocarbon resin will not meet the requirements of high-performance copper-clad laminates; if the molar percentage is too high, it will increase the difficulty and cost of the preparation process.

[0054] (4) The present invention hydrogenates the hydrocarbon resin to maintain low and stable dielectric properties; compared with unhydrogenated hydrocarbon resin, it has stable heat resistance and dielectric properties.

[0055] (5) The low-temperature curing benzocyclobutene-based hydrocarbon resin of the present invention can be used to prepare high-frequency and high-speed copper-clad laminates. The copper-clad laminates prepared have excellent comprehensive properties: dielectric constant of 2.51 to 2.67 and dielectric loss of 0.0008 to 0.0011 at 10 GHz; glass transition temperature of 220 to 233 ℃ and peel strength of 1.15 to 1.25 N / mm.

[0056] (6) The preparation process of the present invention is easy to operate, and the low-temperature curing benzocyclobutene hydrocarbon resin prepared is suitable for the field of high-frequency and high-speed copper clad laminates and has strong practicality. Detailed Implementation

[0057] Part 1: Preparation of low-temperature curing benzocyclobutene-based hydrocarbon resins (synthesis examples 1-4).

[0058] Synthesis example 1:

[0059] Under anhydrous and inert gas conditions, 100g of Ricon 157 hydrocarbon resin (polybutadiene resin, 70% vinyl content), 147.8g of 4-bromomethylbenzocyclobutene, 94.9g of triethylamine, 0.5g of palladium acetate, 1.96g of triphenylphosphine, and 300g of toluene were added sequentially to a clean reaction flask. The mixture was heated to 78℃ and the reaction was monitored by chromatography. When the reaction reached its endpoint, the reactants were washed with water until neutral, filtered, and the toluene was distilled under reduced pressure to obtain 185g of benzocyclobutene-grafted hydrocarbon resin.

[0060] The obtained benzocyclobutene-grafted hydrocarbon resin was dissolved in an appropriate amount of solvent, and 0.26 g of palladium on carbon (Pd / C) catalyst was added. The mixture was stirred evenly, and an appropriate amount of hydrogen gas was introduced. The hydrogenation reaction was carried out at 65 °C and a reaction pressure of 2 MPa for 3 h. After the reaction was completed, the solvent was filtered and distilled under reduced pressure to obtain the low-temperature curing benzocyclobutene-based hydrocarbon resin of Synthetic Example 1. The molar proportion of the benzocyclobutene-based structural unit in the product was 63.0% by 1H NMR analysis. DSC analysis showed that the initial curing temperature without initiator was 165 °C.

[0061] Synthesis example 2:

[0062] Under anhydrous and inert gas conditions, 100g of Ricon 157 hydrocarbon resin (polybutadiene resin, vinyl structure content 70%), 164.5g of 4-bromomethylbenzocyclobutene, 111.3g of triethylamine, 0.65g of palladium acetate, 3.1g of tris(o-methylphenyl)phosphine, and 300g of toluene were added sequentially to a clean reaction flask. The mixture was heated to 84℃ and the reaction was monitored by chromatography. When the reaction reached its endpoint, the reactants were washed with water until neutral, filtered, and the toluene was distilled under reduced pressure to obtain 194g of benzocyclobutene-grafted hydrocarbon resin.

[0063] The obtained benzocyclobutene-grafted hydrocarbon resin was dissolved in an appropriate amount of solvent, and 0.28 g of palladium on carbon (Pd / C) catalyst was added. The mixture was stirred evenly, and an appropriate amount of hydrogen gas was introduced. The hydrogenation reaction was carried out at 70 °C and a reaction pressure of 2 MPa for 3 h. After the reaction was completed, the solvent was filtered and distilled under reduced pressure to obtain the low-temperature curing benzocyclobutene-based hydrocarbon resin of Synthesis Example 2. The molar proportion of the benzocyclobutene-based structural unit in the product was 69.8% by 1H NMR analysis. DSC analysis showed that the initial curing temperature without initiator was 161 °C.

[0064] Synthesis example 3:

[0065] Under anhydrous and inert gas conditions, 100g of Ricon 154 hydrocarbon resin (polybutadiene resin, 90% vinyl content), 171.5g of 4-bromomethylbenzocyclobutene, 118.7g of triethylamine, 0.68g of palladium acetate, 4.1g of tris(o-methylphenyl)phosphine, and 400g of toluene were added sequentially to a clean reaction flask. The mixture was heated to 84℃ and the reaction was monitored by chromatography. When the reaction reached its endpoint, the reactants were washed with water until neutral, filtered, and the toluene was distilled under reduced pressure to obtain 197g of benzocyclobutene-grafted hydrocarbon resin.

[0066] The obtained benzocyclobutene-grafted hydrocarbon resin was dissolved in an appropriate amount of solvent, and 0.28 g of palladium on carbon (Pd / C) catalyst was added. The mixture was stirred evenly, and an appropriate amount of hydrogen gas was introduced. The hydrogenation reaction was carried out at 70 °C and a reaction pressure of 2 MPa for 5 h. After the reaction was completed, the solvent was filtered and distilled under reduced pressure to obtain the low-temperature curing benzocyclobutene-based hydrocarbon resin of Synthesis Example 3. The molar proportion of the benzocyclobutene-based structural unit in the product was 73.1% by 1H NMR analysis. DSC analysis showed that the initial curing temperature without initiator was 158 °C.

[0067] Synthesis example 4:

[0068] Under anhydrous and inert gas conditions, 100g of Ricon 100 hydrocarbon resin (butadiene-styrene copolymer resin, vinyl structure content 70%), 113.0g of 4-chloromethylbenzocyclobutene, 122.5g of potassium carbonate, 0.5g of palladium acetate, 2.6g of tris(o-methylphenyl)phosphine, and 600g of toluene were added sequentially to a clean reaction flask. The mixture was heated to 90℃ and the reaction was monitored by chromatography. When the reaction reached its endpoint, the reactants were washed with water until neutral, filtered, and the toluene was distilled under reduced pressure to obtain 182g of benzocyclobutene-grafted hydrocarbon resin.

[0069] The obtained benzocyclobutene-grafted hydrocarbon resin was dissolved in an appropriate amount of solvent, and 0.26 g of palladium on carbon (Pd / C) catalyst was added. The mixture was stirred evenly, and an appropriate amount of hydrogen gas was introduced. The hydrogenation reaction was carried out at 65 °C and a reaction pressure of 2 MPa for 3 h. After the reaction was completed, the solvent was filtered and distilled under reduced pressure to obtain the low-temperature curing benzocyclobutene-based hydrocarbon resin of Synthesis Example 4. The molar proportion of the benzocyclobutene-based structural unit in the product was 63.0% by 1H NMR analysis. DSC analysis showed that the initial curing temperature without initiator was 168 °C.

[0070] Part 2: Preparation of low dielectric loss copper clad laminates (Examples 1-4).

[0071] S1: Mix 100 parts by weight of low-temperature curing benzocyclobutene hydrocarbon resin, 0.01% to 0.8% of the total resin mass of initiator, 25% to 53% of the total resin mass of filler and solvent (solvent accounts for 34% to 36% of the total mass of all components) uniformly to prepare a resin solution. Immerse the glass fiber cloth (1080E) in the resin solution, remove it, hang it at room temperature to remove most of the solvent, and then bake it in an oven at 130℃ to 150℃ (temperature 1) for 5 to 10 minutes (time 1) to obtain a low dielectric loss semi-cured sheet.

[0072] S2: Several layers of semi-cured sheets are stacked together, and copper foil is attached to both sides. The sheets are placed in a hot press at a temperature of 150-160℃ (temperature 2). Depending on the flow of adhesive, the pressure is gradually increased to 0.2-4MPa (pressure 1) and pressed for 0.5-1h (time 2). The sheets are then hot-pressed at 155-175℃ (temperature 3) for 4-8h (time 3). After natural cooling and depressurization, a low dielectric loss copper-clad laminate is obtained.

[0073] The components, specific dosages, and process parameters of the low dielectric loss copper clad laminates in Examples 1-4 are shown in Table 1:

[0074] Table 1. Components and dosages of low dielectric loss copper clad laminates in Examples 1-4:

[0075]

[0076] The raw materials used in each embodiment in Table 1 are as follows:

[0077] Example 1 uses the low-temperature curing benzocyclobutene-based hydrocarbon resin synthesized in Example 1;

[0078] Example 2 uses the low-temperature curing benzocyclobutene-based hydrocarbon resin synthesized in Example 2;

[0079] Example 3 uses the low-temperature curing benzocyclobutene-based hydrocarbon resin synthesized in Example 3;

[0080] Example 4 uses the low-temperature curing benzocyclobutene-based hydrocarbon resin from Synthesis Example 4;

[0081] The initiator used in Examples 1-4 was dicumyl peroxide (DCP), manufactured by Hongbaoli Group Co., Ltd.

[0082] The filler used in Examples 1-4 was silica, specifically Jiangsu Lianrui DQ1040;

[0083] The solvent used in Examples 1 to 4 was methyl ethyl ketone (MEK).

[0084] Comparative Example 1:

[0085] Following the method of Synthesis Example 2, 164.5g of 4-bromomethylbenzocyclobutene was replaced with 154.5g of 4-bromobenzocyclobutene, while the remaining steps and process parameters remained unchanged. The product was analyzed by 1H NMR, and the molar ratio of the benzocyclobutene group in the structural unit was 69.5%. The initial curing temperature was 208℃ according to DSC analysis.

[0086] 100 parts by weight of benzocyclobutene hydrocarbon resin (Comparative Example 1), 0.3 parts by weight of dicumyl peroxide, 45 parts by weight of silica, and 79 parts by weight of methyl ethyl ketone were uniformly mixed to prepare a resin solution. Glass fibers were immersed in the resin solution and then removed. After being suspended at room temperature to remove most of the solvent, the glass fibers were baked in an oven at 155°C for 10 minutes to obtain a semi-cured sheet. Seven layers of semi-cured sheets were stacked together, and copper foil was attached to both sides. The sheets were placed in a hot press at 160°C and gradually pressurized to 2.2 MPa for 0.5 hours. The temperature was then gradually increased to 175°C and hot-pressed for 7 hours. After natural cooling and depressurization, the copper-clad laminate (Comparative Example 1) was obtained.

[0087] Comparative Example 2:

[0088] 100 parts by weight of benzocyclobutene hydrocarbon resin (Comparative Example 1), 0.3 parts by weight of dicumyl peroxide, 45 parts by weight of silica, and 79 parts by weight of methyl ethyl ketone were uniformly mixed to prepare a resin solution. Glass fibers were immersed in the resin solution and then removed. After being suspended at room temperature to remove most of the solvent, the glass fibers were baked in an oven at 155°C for 10 minutes to obtain a semi-cured sheet. Seven layers of semi-cured sheets were stacked together, and copper foil was attached to both sides. The sheets were placed in a hot press at 160°C and gradually pressurized to 2.2 MPa for 0.5 hours. The temperature was then gradually increased to 215°C and hot-pressed for 7 hours. After natural cooling and depressurization, the copper-clad laminate (Comparative Example 1) was obtained.

[0089] Comparative Example 3:

[0090] The benzocyclobutene-grafted hydrocarbon resin was prepared according to the method of Synthesis Example 2 without hydrogenation treatment.

[0091] 100 parts by weight of benzocyclobutene-grafted hydrocarbon resin (Comparative Example 2), 0.1 parts by weight of dicumyl peroxide, 45 parts by weight of silica, and 79 parts by weight of methyl ethyl ketone were uniformly mixed to prepare a resin solution. Glass fibers were immersed in the resin solution and then removed. After being suspended at room temperature to remove most of the solvent, the glass fibers were baked in an oven at 155°C for 10 minutes to obtain a semi-cured sheet. Eight layers of semi-cured sheets were stacked together, and copper foil was attached to both sides. The sheets were placed in a hot press at 160°C and gradually pressurized to 1.0 MPa for 0.5 hours. The temperature was then gradually increased to 165°C and hot-pressed for 6 hours. After natural cooling and depressurization, the copper-clad laminate (Comparative Example 2) was obtained.

[0092] Comparative Example 4:

[0093] Following the method of Synthesis Example 2, 164.5g of 4-bromomethylbenzocyclobutene was replaced with 123.1g of 4-bromomethylbenzocyclobutene, while the remaining steps and process parameters remained unchanged. The product was analyzed by 1H NMR, and the molar proportion of the benzocyclobutene group in the structural unit was 52.3%. The initial curing temperature was 189℃ according to DSC analysis.

[0094] A resin solution was prepared by uniformly mixing 100 parts by weight of comparative example 3 benzocyclobutene hydrocarbon resin, 0.1 parts by weight of dicumyl peroxide, 45 parts by weight of silica, and 79 parts by weight of methyl ethyl ketone. Glass fibers were immersed in the resin solution and then removed. After being suspended at room temperature to remove most of the solvent, the fiber was baked in an oven at 155°C for 10 minutes to obtain a semi-cured sheet. Seven layers of semi-cured sheets were stacked together, and copper foil was attached to both sides. The sheets were placed in a hot press at 160°C and gradually pressurized to 2.2 MPa for 0.5 hours. The temperature was then gradually increased to 185°C and hot-pressed for 7 hours. After natural cooling and depressurization, the copper-clad laminate of comparative example 3 was obtained.

[0095] The performance parameters of the copper-clad laminates prepared in Examples 1-4 and Comparative Examples 1-4 are compared, as shown in Table 2:

[0096] Table 2:

[0097]

[0098] Note: Df / 10GHz(24h) and Df / 10GHz(90 days) represent the test indicators within 24 hours after sample preparation and under natural light for 90 days.

[0099] As can be seen from the synthesis examples and Table 2, the low-temperature curing benzocyclobutene-based hydrocarbon resin of this application can be cured at a lower temperature and exhibits properties such as high heat resistance, low dielectric constant, low dielectric loss, and good dimensional stability.

[0100] Compared with the comparative examples, the results showed that: Comparative Example 1 used 4-bromobenzocyclobutene-grafted hydrocarbon resin, which had a high curing temperature and was not fully cured under the curing temperature conditions of the examples, resulting in low heat resistance, peel strength, and poor dimensional stability; Comparative Example 2, using 4-bromobenzocyclobutene-grafted hydrocarbon resin, required a higher curing temperature to achieve complete curing and reach the performance level of the examples; Comparative Example 3 used the unhydrogenated hydrocarbon resin of Synthetic Example 2, which had a large number of double bonds remaining in its structure, making it prone to oxidation and yellowing, increasing structural polarity and worsening dielectric loss; In Comparative Example 4, the molar ratio of the alkylbenzocyclobutene structure was less than 62%, and its heat resistance, dimensional stability, and peel strength were all lower than the levels of the examples.

[0101] The relevant standards used for the technical specifications in this article are as follows:

[0102] Glass transition temperature Tg: determined by dynamic thermomechanical analysis (DMA) according to the DMA method specified in 2.4.24.4 of IPC-TM-650;

[0103] Dielectric constant Dk and dielectric loss Df: 10GHz data were tested using the SPDR method according to the method specified in IEC 61189-2-721;

[0104] CTE (Z-axis coefficient of thermal expansion): Tested according to the method specified in 2.4.24.5 of IPC-TM-650;

[0105] Peel strength: The peel strength of the metal capping layer was tested according to the test conditions for "thermal stress" specified in 2.4.8 of IPC-TM-650.

[0106] UL 94 flame retardancy test: determined according to the UL 94 vertical burning test method.

[0107] In the above embodiments and comparative examples, the definition of "solid content" is: the percentage of the mass of non-volatile matter in 100g of sample (i.e., epoxy resin composition resin liquid for copper clad laminate) after baking in an oven at 125°C for 3 hours, and the final solid amount determined by calculating the mass of water solvent added based on the mass of non-volatile matter.

[0108] In the above embodiments: unless otherwise specified, the percentage examples used are mass (weight) percentage examples or percentage examples known to those skilled in the art; unless otherwise specified, the proportions used are mass (weight) proportions; the weight parts can all be grams or kilograms.

[0109] In the above embodiments, the process parameters (temperature, time, concentration, pressure, etc.) and the dosage values ​​of each component in each step are within a range, and any point can be applied.

[0110] The technical contents of this invention and the above embodiments that are not specifically described are the same as those of the prior art, and the raw materials are all commercially available products.

Claims

1. A low-temperature curing benzocyclobutene-based hydrocarbon resin, characterized in that, It comprises a hydrocarbon resin backbone and an alkylbenzocyclobutene group; the hydrocarbon resin backbone has a plurality of alkyl or aralkyl groups; the alkylbenzocyclobutene group is grafted onto at least one of the plurality of alkyl or aralkyl groups.

2. The low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 1, characterized in that, The low-temperature curing benzocyclobutene-based hydrocarbon resin has the general chemical structural formula shown in (Ⅰ): Where x is any integer from 1 to 100, and y and z are any integers from 0 to 50; R1, R2, R4, R7, R8, R9, R 10 R 11 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms; R3 is selected from one or more of single bonds, alkyl groups containing 2 to 10 carbon atoms, and aralkyl groups containing 8 to 12 carbon atoms; R5 is selected from benzocyclobutenyl-substituted methyl groups ( It consists of two or more alkyl groups containing 2 to 10 carbon atoms and aralkyl groups containing 8 to 12 carbon atoms, and must contain a benzocyclobutenyl-substituted methyl group. ); R6 is selected from hydrogen, phenyl, benzocyclobutenyl-substituted methyl groups ( ( ), one or more of the following: alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms.

3. The low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 1, characterized in that, The low-temperature curing benzocyclobutenyl hydrocarbon resin contains benzocyclobutenyl monosubstituted methyl groups ( The molar percentage of the structural unit containing ) is 62% to 75%.

4. The low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 1, characterized in that, The general chemical structural formula of the hydrocarbon resin is shown in Formula (II): Where k is any integer from 1 to 100, and j and n are any integers from 0 to 50; R 12 R 14 R 15 R 17 R 18 R 19 R 20 R 21 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms; R 13 It is an alkyl group containing one unsaturated bond and 2 to 10 carbon atoms, or an aralkyl group containing one unsaturated bond and 8 to 12 carbon atoms; R 16 It is selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms.

5. A method for preparing a low-temperature curing benzocyclobutene-based hydrocarbon resin according to any one of claims 1-4, characterized in that, The hydrocarbon resin is subjected to a Heck reaction with halomethylbenzocyclobutene, and then the benzocyclobutene-grafted hydrocarbon resin is subjected to a hydrogenation reaction to completely eliminate the remaining double bonds in its structure, thus obtaining a low-temperature curing benzocyclobutene-based hydrocarbon resin.

6. The method for preparing a low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 5, characterized in that, Specifically, the steps include the following: a. Preparation of benzocyclobutene-grafted hydrocarbon resin: Under anhydrous and inert gas conditions, weigh an appropriate amount of hydrocarbon resin into a reaction flask, add a measured amount of halomethylbenzocyclobutene, acid-binding agent, catalyst A, and solvent A, and maintain the reaction temperature at 70-100℃ to allow the hydrocarbon resin to react with halomethylbenzocyclobutene; monitor the degree of reaction by chromatography during the reaction to determine the reaction endpoint; after the reaction is completed, wash the reactants with water until neutral, filter, and distill under reduced pressure to obtain benzocyclobutene-grafted hydrocarbon resin. b. Catalytic hydrogenation of benzocyclobutene-grafted hydrocarbon resin: The benzocyclobutene-grafted hydrocarbon resin from step a is dissolved in an appropriate amount of solvent B, and catalyst B with a mass fraction of 0.01% to 0.8% of the benzocyclobutene-grafted hydrocarbon resin is added. The mixture is stirred evenly, and an appropriate amount of hydrogen gas is introduced. The hydrogenation reaction is carried out at 20 to 100°C and a reaction pressure of 0.1 to 7 MPa for 1 to 10 hours. After the reaction is completed, the resin is filtered or washed with pure water and distilled under reduced pressure to obtain the low-temperature cured benzocyclobutene-based hydrocarbon resin.

7. The method for preparing a low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 5, characterized in that, The benzocyclobutene-grafted hydrocarbon resin has the general chemical structural formula shown in (III): Where g is any integer from 1 to 100, and m and f are any integers from 0 to 50; R 22 R 24 R 26 R 28 R 29 R 30 R 31 R 32 Each is independently selected from one or more of hydrogen, phenyl, alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms; R 23 It is selected from one or more of the following: single bond, alkyl group containing 2 to 10 carbon atoms, aralkyl group containing 8 to 12 carbon atoms, alkyl group containing 1 unsaturated bond and containing 2 to 10 carbon atoms, and aralkyl group containing 1 unsaturated bond and containing 8 to 12 carbon atoms; R 25 Selected from benzocyclobutenyl monosubstituted methyl ( It comprises two or more of the following: an alkyl group containing one unsaturated bond and having 2 to 10 carbon atoms, and an aralkyl group containing one unsaturated bond and having 8 to 12 carbon atoms, wherein it must contain a benzocyclobutenyl-substituted methyl group. ); R 27 Self-substituted methyl groups of hydrogen, phenyl, benzocyclobutenyl ( ( ), one or more of the following: alkyl groups containing 1 to 10 carbon atoms, and aralkyl groups containing 7 to 12 carbon atoms.

8. The method for preparing a low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 6, characterized in that, The molar ratio of the double bond between the halomethylbenzocyclobutene and the benzocyclobutene-grafted hydrocarbon resin is (0.7-1):1; the molar ratio of the acid-binding agent to the halomethylbenzocyclobutene is (1-1.5):

1.

9. The method for preparing a low-temperature curing benzocyclobutene-based hydrocarbon resin according to claim 6, characterized in that, The catalyst A is a mixture of a metal compound and a ligand; the molar ratio of the metal compound to the ligand is 1: (2.4~6.0), wherein the molar ratio of the metal compound to halomethylbenzocyclobutene is (2×10) -3 ~7×10 -3 ):

1.

10. The application of the low-temperature curing benzocyclobutene-based hydrocarbon resin according to any one of claims 1-4 in the preparation of low dielectric loss copper-clad laminates, characterized in that, The method for preparing the low dielectric loss copper clad laminate is as follows: S1. Mix 100 parts by weight of low-temperature curing benzocyclobutene hydrocarbon resin, 0.01% to 0.08% of the total resin mass of initiator, 25% to 53% of the total resin mass of filler and solvent evenly to prepare a resin solution. Place glass fiber in the resin solution for immersion and then remove it. Hang it at room temperature to remove most of the solvent, and then place it in an oven at 130℃ to 150℃ for baking for 5 to 10 minutes to obtain a low dielectric loss semi-cured sheet. S2. Stack several layers of semi-cured sheets and attach copper foil to both sides. Place them in a hot press at a temperature of 150-160℃. Gradually increase the pressure to 0.2-4MPa depending on the adhesive flow. Press for 0.5-1h and then hot press at 155-175℃ for 4-8h. After natural cooling and depressurization, a low dielectric loss copper-clad laminate is obtained.

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