An allyl polyphenylene ether resin, a preparation method thereof, a flexible low-dielectric material, and a preparation method thereof

Abstract

The present invention discloses an allyl polyphenylene ether resin and its preparation method, a flexible low-dielectric material and its preparation method. The preparation method of the flexible low-dielectric material includes: reacting a polyphenylene ether resin with a brominating agent to obtain a brominated polyphenylene ether resin, and then subjecting the brominated polyphenylene ether to an amination reaction with allylamine to obtain a polyphenylene ether resin with a high allyl content; under the action of a photoinitiator, carrying out a thiol-ene click chemical reaction on the allyl polyphenylene ether resin and dithiol under ultraviolet light conditions, and then heating and curing to obtain the flexible low-dielectric material. The preparation method of the present invention is simple, the raw materials are easy to obtain, the preparation period is short, and the low-dielectric performance of the cured flexible material is stable.

Description

Technical Field

[0001] The present invention relates to the field of synthesis and preparation of polymer materials, and particularly relates to an allyl polyphenylene ether resin and a preparation method thereof, a flexible low-dielectric material and a preparation method thereof. Background Art

[0002] Polyphenylene ether resin is an engineering plastic with excellent dimensional stability, heat resistance, insulation performance and low dielectric properties, and is commonly used in fields such as electronic packaging, insulating materials, and instrument parts. However, with the development of flexible electronic packaging technologies such as smart wearables, biomedicine, flexible displays, and new energy, the demand for corresponding packaging materials is becoming increasingly urgent, and the performance requirements for flexible packaging materials are getting higher and higher. Currently, general polyphenylene ether has no active functional groups and is generally used in combination with other resins. However, it has a high melt viscosity, poor fluidity, difficult processing and molding, and poor compatibility with other resins, which limits its industrial application. In addition, the molecular chain of polyphenylene ether contains a large number of benzene rings, and this rigid structure also limits its application in the field of flexible low-dielectric materials. Therefore, it is of great significance to develop polyphenylene ether resin with active functional groups as a flexible packaging material.

[0003] Currently, commonly used flexible electronic materials include polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), and polyethylene naphthalate glycol ester. However, these materials all contain polar groups such as alcohol hydroxyl groups, ester groups, and amine groups, with a relatively high polarizability and dielectric constant, making them unsuitable for applications in low-dielectric scenarios. For the modification of polyphenylene ether materials, mainly through blending with polystyrene (PS), high-impact polystyrene (HIPS), ethylene-propylene-diene monomer (EPDM), etc. to improve fluidity and reduce the dielectric constant. Chinese Patent Application CN115725167A (Cao Yanxiao, Li Xianhong, Ran Guowen, Lan Xiucai, Zhou Shufen) A polyphenylene ether-based composite material with low dielectric constant and low dielectric loss and its preparation method, Chinese Patent, March 3, 2023, prepared a polyphenylene ether-based composite material with low dielectric constant and low dielectric loss through polyphenylene ether resin, polystyrene resin, fluororesin, hollow glass microspheres, etc. While meeting the low dielectric properties of the material, it can maintain its mechanical strength and toughness. However, this method obtains a low-dielectric alloy material through the blending of various resins and additives, with poor flexibility. None of the raw materials used have active functional groups, making it difficult to form an effective adhesion to the substrate. In addition, for the modification of polyphenylene ether resin, active functional groups are introduced through end-group esterification, epoxidation, vinylation, etc. to enhance the reaction activity. Chinese Patent Application CN117487155A (Xiao Zhichun) A method for preparing a modified low-molecular-weight bifunctional polyphenylene ether oligomer with vinyl-terminated polyphenylene ether, Chinese Patent, February 2, 2024, through saponification reaction, vinyl-terminated the low-molecular-weight polyphenylene ether, introduced unsaturated double bonds, and used them together with styrene, allyl methacrylate, and other unsaturated polyester monomers and resins to cure and crosslink under a thermal oxygen environment, preparing a material with strong dielectric properties, good insulation performance, and extremely low hygroscopicity, suitable for electronic power packaging of PCB boards, copper-clad laminates, 5G, and 6G. However, this method vinyl-terminates the polyphenylene ether, with a relatively low double bond content and fewer active sites, affecting the curing network. In addition, the allyl methacrylate and unsaturated polyester monomers used in combination both contain polar functional groups, increasing the molecular polarizability and being unfavorable for reducing the dielectric properties. In addition, as a thermosetting resin, the allyl content of allyl polyphenylene ether directly affects the crosslinking density, heat resistance, and mechanical properties of the material. Currently, there is an industrial product of allylated polyphenylene ether (Asahi Kasei S2100), which is prepared by lithiation reaction of polyphenylene ether with n-butyllithium and then reaction with allyl bromide to form allylated polyphenylene ether. This thermosetting allylated polyphenylene ether has the characteristics of low dielectric constant and higher circuit signal transmission speed compared to epoxy resin, polyimide resin, and cyanate resin. However, in order to improve the allyl substitution rate, the control of reaction time and reaction conditions is relatively strict, and only one allyl group can be introduced at the corresponding active sites of the lithiated body, which is unfavorable for increasing the allyl content, thus limiting the further improvement of the thermal curing performance of the material. Summary of the Invention

[0004] In view of the problems existing in the background art, the object of the present invention is to provide an allyl polyphenylene ether resin and its preparation method, a flexible low-dielectric material and its preparation method. By preparing a novel side-allyl polyphenylene ether resin, a diallyl structure is introduced into the molecular structure of the polyphenylene ether through an amination reaction, greatly increasing the content of the active functional group allyl in the resin. And through a click reaction with dithiol in a solvent, after curing, it has intrinsic high flexibility and low dielectric properties. The resin does not contain strongly polar groups and at the same time has the rigid backbone of polyphenylene ether and the flexible structure of dithiol. Therefore, this structure can reduce the dielectric constant and dielectric loss of the resin, and maintain excellent flexibility and hydrophobic properties. Moreover, the solvent method improves its processability and the interaction force with various fillers, which is of great significance for the practical application in the flexible electronics industry.

[0005] One of the objects of the present invention is to provide a preparation method of an allyl polyphenylene ether resin, which comprises the following steps: (1) reacting polyphenylene ether with a brominating agent to obtain brominated polyphenylene ether; (2) reacting the brominated polyphenylene ether with an allyl compound to obtain an allyl polyphenylene ether resin.

[0006] Optionally, in step (1), by the solvent method, polyphenylene ether and tetrahydrofuran are dissolved at a mass ratio of 1:(3 - 5). After fully dissolving, the polyphenylene ether, the brominating agent, and dibenzoyl peroxide are added at a molar ratio of 1:(20 - 30):(0.2 - 0.5) for reaction. The reaction temperature is maintained at 70 - 80 °C. The reaction is carried out under the protection of high-purity nitrogen for 2 h, then cooled to room temperature, and washed with anhydrous methanol. After liquid separation, the precipitate is obtained, vacuum dried, washed and dried in this way for 3 - 4 times, and finally vacuum dried to obtain a solid brominated polyphenylene ether resin.

[0007] Optionally, the brominated polyphenylene ether prepared according to step (1) and tetrahydrofuran are dissolved at a mass ratio of 1:(3 - 5). After fully dissolving, the brominated polyphenylene ether, the allyl compound, and potassium carbonate are added at a molar ratio of 1:(10 - 20):(3 - 5) for reaction. The reaction temperature is maintained at 45 - 50 °C. The reaction is carried out under the protection of high-purity nitrogen for 8 h, then cooled to room temperature, and washed with anhydrous methanol. After liquid separation, the precipitate is obtained, vacuum dried, washed and dried in this way for 3 - 4 times, and finally vacuum dried to obtain a solid allyl polyphenylene ether resin (ALPPO).

[0008] Optionally, in step (1), the brominating agent is at least one of N-bromosuccinimide, N-bromo-o-sulfobenzimide, 1,3-dibromo-5,5-dimethylhydantoin, carbon tetrabromide, 1,3,5-tribromo-1,3,5-triazine-2,4,6-trione.

[0009] Optionally, the brominating agent in step (1) is N-bromosuccinimide.

[0010] Optionally, the allyl compound described in step (2) is diallylamine.

[0011] The second object of the present invention is to provide an allyl polyphenylene ether resin based on a double-bond-containing polyphenylene ether resin obtained by the preparation method as described above.

[0012] The third object of the present invention is to provide a preparation method of a flexible low-dielectric material, which includes the following steps: After fully dissolving the allyl polyphenylene ether resin obtained by the preparation method according to any one of claims 1 to 6 and tetrahydrofuran in a mass ratio of 1:(3 to 5), add the allyl polyphenylene ether resin, dithiol, and photoinitiator in a molar ratio of 1:(5 to 8):(0.01 to 0.03), and react under room temperature ultraviolet light conditions for 0.5 to 1 h to obtain a solvent-based mixture; perform desolvation treatment on the solvent-based mixture obtained in step (1), and cure at 60 to 90 °C for 6 to 12 hours to obtain the flexible low-dielectric material.

[0013] Optionally, the dithiol is at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,16-hexadecanedithiol, and polyethylene glycol dithiol.

[0014] Optionally, the photoinitiator is at least one of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-hydroxycyclohexyl phenyl ketone.

[0015] The fourth object of the present invention is to provide a flexible low-dielectric material obtained by the preparation method as described above.

[0016] The beneficial effects of the present invention are as follows:

[0017] The preparation method of the present invention can prepare an allyl polyphenylene ether resin with excellent performance. The preparation method is simple, the raw materials are easy to obtain, the preparation period is short, and the low-dielectric performance of the cured flexible material is stable. Description of the Drawings

[0018] Figure 1 It is the molecular structure of the allyl polyphenylene ether resin ALPPO in Example 1.

[0019] Figure 2 It is the infrared spectrum of the allyl polyphenylene ether resin ALPPO in Example 1.

[0020] Figure 3 It is the 1 H-NMR of the allyl polyphenylene ether resin ALPPO in Example 1.

[0021] Figure 4Graph showing the relationship between the dielectric constant, dielectric loss and frequency of the flexible low-dielectric material in Example 1.

[0022] Figure 5 DMA graph of the flexible low-dielectric material in Example 1. Detailed implementation mode

[0023] To make the above objects, features and advantages of the invention more obvious and understandable, the following provides a detailed description of the specific implementation mode of the present invention.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0025] The preparation method of the allyl polyphenylene ether resin according to the present invention includes the following steps: (1) Reacting polyphenylene ether with a brominating agent to obtain brominated polyphenylene ether; (2) Reacting the brominated polyphenylene ether with an allyl compound to obtain an allyl polyphenylene ether resin.

[0026] In step (1), by the solvent method, polyphenylene ether and tetrahydrofuran are dissolved at a mass ratio of 1:(3 - 5). After complete dissolution, the polyphenylene ether, brominating agent, and dibenzoyl peroxide are added in a molar ratio of 1:(20 - 30):(0.2 - 0.5) for reaction. The reaction temperature is maintained at 70 - 80°C. After reacting for 2 h under the protection of high-purity nitrogen, it is cooled to room temperature and then washed with anhydrous methanol. After liquid separation, a precipitate is obtained, which is dried in vacuum. Such washing and drying are carried out 3 - 4 times, and finally dried in vacuum to obtain a solid brominated polyphenylene ether resin.

[0027] In step (2), the brominated polyphenylene ether prepared according to step (1) and tetrahydrofuran are dissolved at a mass ratio of 1:(3 - 5). After complete dissolution, the brominated polyphenylene ether, allyl compound, and potassium carbonate are added in a molar ratio of 1:(10 - 20):(3 - 5) for reaction. The reaction temperature is maintained at 45 - 50°C. After reacting for 8 h under the protection of high-purity nitrogen, it is cooled to room temperature and then washed with anhydrous methanol. After liquid separation, a precipitate is obtained, which is dried in vacuum. Such washing and drying are carried out 3 - 4 times, and finally dried in vacuum to obtain a solid allyl polyphenylene ether resin (ALPPO).

[0028] In step (1), the brominating agent can be at least one of N-bromosuccinimide, N-bromo-o-sulfobenzimide, 1,3-dibromo-5,5-dimethylhydantoin, carbon tetrabromide, 1,3,5-tribromo-1,3,5-triazine-2,4,6-trione. The brominating agent is preferably N-bromosuccinimide.

[0029] In step (2), the allyl compound is preferably diallylamine.

[0030] The allyl polyphenylene ether resin with a high allyl content prepared by the above preparation method can be applied to the field of low dielectric materials.

[0031] The preparation method of the flexible low dielectric material according to the present invention includes the following steps: (1) After the allyl polyphenylene ether resin prepared by the above preparation method and tetrahydrofuran are fully dissolved at a mass ratio of 1:(3-5), the allyl polyphenylene ether resin, dithiol, and photoinitiator are added at a molar ratio of 1:(5-8):(0.01-0.03), and reacted under room temperature ultraviolet light conditions for 0.5-1 h to obtain a solvent-based mixture; (2) The solvent-based mixture obtained in step (1) is subjected to desolvation treatment and cured at 60-90 °C for 6-12 hours to obtain the flexible low dielectric material.

[0032] The dithiol is at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,16-hexadecanedithiol, and polyethylene glycol dithiol. The dithiol is preferably an alkane chain dithiol, more preferably 1,10-decanedithiol.

[0033] The photoinitiator is at least one of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-hydroxycyclohexyl phenyl ketone. The photoinitiator is preferably (2,4,6-trimethylbenzoyl) diphenylphosphine oxide.

[0034] The flexible low dielectric material prepared by the above preparation method has excellent comprehensive properties.

[0035] The allyl polyphenylene ether resin of the present invention and its preparation method, the flexible low dielectric material and its preparation method will be specifically described below by examples. Main raw materials and equipment used: Unless otherwise specified, the raw materials and equipment in each example and comparative example are the same; materials without specifying specific models or types are from the common same model purchased from the market and are not specifically limited.

[0036] Example 1

[0037] (1) In a 500 ml three-necked flask, 10 g of polyphenylene ether and 50 g of tetrahydrofuran were fully dissolved, and then 10 g of polyphenylene ether, 26 g of N-bromosuccinimide, and 0.5 g of dibenzoyl peroxide were added for reaction. The reaction temperature was maintained at 70-80 °C, and the reaction was carried out under the protection of high-purity nitrogen for 2 h. After cooling to room temperature, anhydrous methanol was added for washing, and the precipitate was obtained by liquid separation and vacuum dried. This washing was carried out 3-4 times, and finally vacuum dried to obtain a solid brominated polyphenylene ether resin.

[0038] (2) In a 500 ml three-necked flask, 10 g of brominated polyphenylene oxide and 50 g of tetrahydrofuran were fully dissolved, then another 10 g of brominated polyphenylene oxide, 7 g of diallylamine, and 2.4 g of potassium carbonate were added for reaction. The reaction temperature was maintained at 45 - 50 °C. The reaction was carried out under the protection of high-purity nitrogen for 8 h, then cooled to room temperature and washed with anhydrous methanol. The precipitate was obtained by liquid separation and dried in vacuum. This washing process was repeated 3 - 4 times, and finally, the solid allyl polyphenylene oxide resin (ALPPO) was obtained by vacuum drying. The molecular structure of the reaction product is shown in Figure 1 , where m≥0, n≥0, x≥0, y≥0. The infrared and NMR spectra of the reactant PPO and the product ALPPO are shown in Figure 2 and Figure 3 .

[0039] (3) In a 100 ml beaker, 5 g of allyl polyphenylene oxide resin was added, and then 15 g of tetrahydrofuran was added and fully dissolved. Another 5 g of allyl polyphenylene oxide, 3 g of 1,10-decanedithiol (DCD), and 0.01 g of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide were added for reaction. The reaction was carried out under ultraviolet light at room temperature for 0.5 h. The obtained solvent-based mixture was placed in a mold with a specific shape and baked at 80 °C for 10 h. After the solvent was fully volatilized and cured, the temperature was lowered to obtain the final flexible film material.

[0040] For the material obtained by the above method, dielectric property tests were carried out on a 10*10*1 mm 3 spline using an Agilent 4294A instrument. The dielectric constant of the material at 25 °C and 1 MHz was 3.14, and the results are shown in Figure 4 . By using a universal material testing machine, tensile tests were carried out on dumbbell-shaped splines. The tensile strength of the material at a tensile rate of 5 mm / min at 25 °C was 7.4 MPa, and the elongation at break was 18%, indicating good mechanical strength and flexibility.

[0041] Among them, Figure 1 is the molecular structure of the allyl polyphenylene oxide resin.

[0042] Figure 2 Near 3070 cm -1 is the characteristic peak of the C-H stretching vibration of the allyl unsaturated bond, near 1637 cm -1 is the C=C characteristic peak, and near 919 cm -1 is the characteristic peak of the C-H bending vibration of the allyl unsaturated bond.

[0043] Figure 5 is the DMA test result of this material. Its glass transition temperature Tg is 56.5 °C, and the storage modulus at 25 °C is 390 MPa.

[0044] As can be seen from the above test results, the flexible low-dielectric material prepared in Example 1 has excellent comprehensive performance.

[0045] Example 2

[0046] (1) As described in step (1) of Example 1, except for 10 g of polyphenylene ether, 22 g of N-bromosuccinimide, and 0.5 g of dibenzoyl peroxide, other methods are the same as those in step (1) of Example 1 to obtain brominated polyphenylene ether.

[0047] (2) As described in step (2) of Example 1, except for 10 g of brominated polyphenylene ether, 5 g of diallylamine, and 2.4 g of potassium carbonate, other methods are the same as those in step (2) of Example 1 to obtain allyl polyphenylene ether.

[0048] (3) As described in step (3) of Example 1, except for 5 g of allyl polyphenylene ether, 2.8 g of 1,6-hexanedithiol, and 0.01 g of (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, other methods are the same as those in step (3) of Example 1. And the final flexible thin film material is obtained.

[0049] For the material obtained by the above method, through dielectric property testing, the dielectric constant of the material at 25 °C and 1 MHz is 3.23, the tensile strength is 8.8 MPa, and the elongation at break is 16%, with good flexibility and low dielectric properties.

[0050] Example 3

[0051] (1) As described in step (1) of Example 1, except for 10 g of polyphenylene ether, 25 g of N-bromosuccinimide, and 0.5 g of dibenzoyl peroxide, other methods are the same as those in step (1) of Example 1 to obtain brominated polyphenylene ether.

[0052] (2) As described in step (2) of Example 1, except for 10 g of brominated polyphenylene ether, 6 g of diallylamine, and 2.4 g of potassium carbonate, other methods are the same as those in step (2) of Example 1 to obtain allyl polyphenylene ether.

[0053] (3) As described in step (3) of Example 1, except for 5 g of allyl polyphenylene ether, 4 g of 1,16-hexadecanedithiol, and 0.01 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone, other methods are the same as those in step (3) of Example 1. And the final flexible thin film material is obtained.

[0054] For the material obtained by the above method, through dielectric property testing, the dielectric constant of the material at 25 °C and 1 MHz is 3.03, the tensile strength is 5.5 MPa, and the elongation at break is 21%, with good flexibility and low dielectric properties.

Claims

1. A method for preparing an allyl polyphenylene ether resin, characterized in that: The following steps are involved: (1) using polyphenylene ether to react with a brominating agent to obtain brominated polyphenylene ether; (2) Allyl polyphenylene ether resin is obtained by reacting brominated polyphenylene ether with diallylamine.

2. The method for preparing the allyl polyphenylene ether resin according to claim 1, characterized in that: In step (1), polyphenylene ether and tetrahydrofuran are dissolved in a mass ratio of 1:(3-5) by a solvent method, and after sufficient dissolution, polyphenylene ether, a brominating agent, and dibenzoyl peroxide are added in a molar ratio of 1:(20-30):(0.2-0.5) to react, and the reaction temperature is maintained at 70-80° C. The reaction is carried out under the protection of high-purity nitrogen for 2 hours, and then cooled to room temperature and washed with anhydrous methanol, and the precipitate is separated to obtain a precipitate, which is vacuum dried, washed and dried 3-4 times, and finally vacuum dried to obtain a solid brominated polyphenylene ether resin.

3. The method for preparing the allyl polyphenylene ether resin according to claim 1, characterized in that: In step (2), the brominated polyphenylene ether prepared according to step (1) and tetrahydrofuran are dissolved in a mass ratio of 1:(3-5), and after sufficient dissolution, the brominated polyphenylene ether, the allyl compound and potassium carbonate are added in a molar ratio of 1:(10-20):(3-5) for reaction, the reaction temperature is maintained at 45-50°C, the reaction is carried out under the protection of high-purity nitrogen for 8 hours, and then cooled to room temperature, anhydrous methanol is added for washing, and the precipitate is separated to obtain a precipitate, which is vacuum dried, and the washing and drying are repeated 3-4 times, and finally vacuum dried to obtain a solid allyl polyphenylene ether resin (ALPPO).

4. The method for preparing the allyl polyphenylene ether resin according to claim 2, characterized in that: In step (1), the brominating agent is at least one of N-bromosuccinimide, N-bromo-o-sulfonylbenzene imide, 1,3-dibromo-5,5-dimethylhydantoin, 4-carbon tetrabromide, and 1,3,5-tribromo-1,3,5-triazine-2,4,6-trione.

5. The method for preparing allyl polyphenylene ether resin according to claim 4, characterized in that: The brominating agent in step (1) is N-bromosuccinimide.

6. A method for preparing a flexible low dielectric material, characterized in that: The following steps are involved: (1) After fully dissolving the allyl polyphenylene ether resin obtained by the preparation method of any one of claims 1 to 5 and tetrahydrofuran in a mass ratio of 1:(3-5), adding the allyl polyphenylene ether resin, dithiol, and photoinitiator in a molar ratio of 1:(5-8):(0.01-0.03), reacting under ultraviolet light at room temperature for 0.5-1h to obtain a solvent-based mixture; (2) Desolventizing the solvent-based mixture obtained in step (1), and curing it at 60 to 90° C. for 6 to 12 hours to obtain the flexible low-dielectric material.

7. The method for preparing a flexible low dielectric material according to claim 6, characterized in that: The dithiol is at least one of 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol, 1,16-hexadecanedithiol and polyethylene glycol dithiol.

8. The method for preparing a flexible low dielectric material according to claim 7, characterized in that: The photoinitiator is at least one of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 1-hydroxycyclohexylphenyl ketone.

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