PPO resin for ultra-high frequency high-speed printed circuit boards
By crosslinking a crosslinking agent containing multiple unsaturated alkenyl substituents with low molecular weight polyphenylene ether, a three-dimensional chemical bond network is formed. By utilizing the synergistic flame retardancy of nitrogen and phosphorus elements, the problems of flammability and unstable dielectric properties of PPO resin are solved, achieving low dielectric properties at high frequencies and flame retardant performance with a UL94 V-0 rating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KUNSHAN SUMEI FINE CHEM CO LTD
- Filing Date
- 2026-06-23
- Publication Date
- 2026-07-31
AI Technical Summary
Existing PPO resins have problems with flammability and insufficient flame retardancy in ultra-high frequency applications. Traditional flame retardants increase dielectric loss and are unstable at high frequencies, making it difficult to simultaneously meet the UL94 V-0 rating and low dielectric performance requirements.
A crosslinking agent containing multiple unsaturated alkenyl substituents is used to crosslink with low molecular weight polyphenylene ether to form a three-dimensional chemical bond network. The flame retardant properties are improved by forming a dense porous carbon layer through the synergistic flame retardancy of nitrogen and phosphorus elements, while maintaining low dielectric properties.
It achieves UL94 V-0 flame retardant performance while maintaining low dielectric constant and low dielectric loss at high frequencies, avoiding the problems of dielectric property degradation and migration precipitation of traditional flame retardants.
Smart Images
Figure CN122483545A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of resin technology, specifically relating to a PPO resin for ultra-high frequency and high-speed printed circuit boards. Background Technology
[0002] With the rapid development of fifth-generation mobile communication (5G), millimeter-wave radar, satellite communication, and high-speed data centers, printed circuit boards (PCBs) are evolving towards higher frequencies, higher speeds, and higher integration. Especially in the ultra-high frequency band above 10 GHz, extremely stringent requirements are placed on the dielectric properties of substrate materials: they must possess stable low dielectric constants (Dk) and ultra-low dielectric loss factors (Df) to reduce signal transmission delay and attenuation, while ensuring the stability of dielectric performance over a wide bandwidth and temperature range.
[0003] Polyphenylene oxide (PPO, also known as PPE) resin possesses excellent intrinsic dielectric properties due to its low content of polar groups and good symmetry in its molecular structure, with typical dielectric constants (Df) as low as 0.002~0.005 (10 GHz). It also exhibits high heat resistance, low water absorption, and good dimensional stability, making it one of the most promising main resins for ultra-high frequency and high-speed PCB substrates. However, unmodified PPO resin has inherent drawbacks: as a predominantly hydrocarbon-based polymer, it has a low limiting oxygen index and is inherently flammable. Once exposed to fire, it will continue to burn and produce a large amount of molten droplets, severely failing to meet the PCB industry's mandatory requirements for flame retardant performance.
[0004] Currently, the industrial practice of imparting flame retardancy to PPO systems involves blending with bromine- or phosphorus-containing flame retardants. However, for ultra-high frequency applications, traditional flame retardant solutions face a significant challenge: while bromine-containing flame retardants offer high flame retardancy, most bromine-based flame retardants, due to the presence of highly polar C-Br bonds in their molecules, significantly increase the dielectric loss (Dk) and dielectric constant (Df) at high frequencies, especially above 10 GHz, where the increase can reach 30%–50%, severely undermining the original low-loss advantage of PPO. Traditional small-molecule organophosphorus flame retardants are prone to migration and precipitation during high-temperature and high-humidity aging, leading not only to a decrease in flame retardant performance but also to dielectric drift and circuit corrosion risks. Therefore, achieving efficient halogen-free flame retardancy while maintaining ultra-low dielectric loss and good processability of PPO resin, and simultaneously meeting the UL94 V-0 rating (especially for thin substrates), has become a pressing technical challenge in the high-speed, high-frequency copper-clad laminate field. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a PPO resin for ultra-high frequency and high speed printed circuit boards.
[0006] A first aspect of the present invention provides a PPO resin for ultra-high frequency and high-speed printed circuit boards, which is made from a raw material comprising the following raw materials measured in parts by weight:
[0007] Low molecular weight polyphenylene ether: 82-96 parts;
[0008] Crosslinking agent: 3.5-6.8 parts;
[0009] Initiator: 0.1-0.3 parts;
[0010] Organic solvent: 60-80 parts;
[0011] The crosslinking agent is a phosphorus allyl ether derivative in its structure.
[0012] As a preferred embodiment of the present invention, the method for preparing the PPO resin includes the following steps:
[0013] Step 1: Mix low molecular weight polyphenylene ether, crosslinking agent and organic solvent to form a homogeneous mixture, then add initiator and mix until a homogeneous adhesive is formed;
[0014] Step 2: Immerse the fiberglass cloth fully in the adhesive solution, pull it out at a uniform speed after 15 seconds, and after it is completely dried at room temperature, transfer it to an oven and bake it at a temperature of 140-150℃ for 5-10 minutes to form a semi-cured sheet.
[0015] The third step is to rub the resin powder off the prepreg and pour it into a mold for hot pressing and curing to obtain PPO resin.
[0016] As a preferred embodiment of the present invention, the method for preparing the crosslinking agent includes the following steps:
[0017] Step A: Under nitrogen protection, pentaerythritol triallyl ether is added to toluene and stirred until homogeneous. Then, catalyst is added and mixed. Next, halogen-modifying reagent is added in an ice-water bath. After the addition is complete, the ice bath is removed and the temperature is raised to 40-50℃ at a rate of 1-2℃ / min. After stirring for 4-6 hours, heating is stopped and the mixture is allowed to cool naturally. The mixture is then filtered to remove impurities. The filtrate is washed, dried with anhydrous sodium sulfate, and the product is separated by vacuum distillation to obtain the haloallyl ether derivative.
[0018] Step B: Add the haloallyl ether derivative and 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide to N,N-dimethylformamide, purge with nitrogen for protection, start stirring, and mix thoroughly. Then add an alkaline acid-binding agent, raise the temperature to 80-100℃, and continue stirring for 6-12 hours. Stop heating, cool to room temperature, filter to remove salt, collect the crude product by vacuum distillation, and purify by washing, drying, and recrystallization to obtain the crosslinking agent.
[0019] As a preferred embodiment of the present invention, in step A, the molar ratio of pentaerythritol triallyl ether to halogen-modifying reagent is 1:1.
[0020] As a preferred embodiment of the present invention, in step A, the catalyst is any one of dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, methyl tin mercaptan, or octyl tin mercaptan.
[0021] As a preferred embodiment of the present invention, in step A, the halogen modifying agent is any one of chloroethyl isocyanate, 3-chloropropyl isocyanate, or ethyl 2-bromoisocyanate.
[0022] As a preferred embodiment of the present invention, in step B, the molar ratio of the haloallyl ether derivative and 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide is 1:1.
[0023] As a preferred embodiment of the present invention, in step B, the alkaline acid-binding agent is potassium carbonate.
[0024] As a preferred embodiment of the present invention, the initiator is bis-tert-butylperoxyisopropylbenzene.
[0025] As a preferred embodiment of the present invention, the organic solvent is acetone.
[0026] Compared with the prior art, the present invention has the following beneficial effects:
[0027] This invention achieves crosslinking of low molecular weight polyphenylene ether by preparing a crosslinking agent containing multiple unsaturated alkenyl substituents in its structure. This crosslinking method forms a three-dimensional chemical bond network between the polyphenylene ether molecular chains, "anchoring" the molecular chains and significantly restricting the degrees of freedom of movement of the molecular chain segments under an alternating electric field. The orientation and long-range motion of the dipoles are suppressed, resulting in a reduction in the contribution of orientation polarization, and consequently a reduction in dielectric constant and loss, thus enabling the PPO resin to maintain its low dielectric constant characteristics.
[0028] Furthermore, the nitrogen and phosphorus elements contained in the crosslinking agent structure enter the polyphenylene ether molecular chain through crosslinking, avoiding migration and precipitation problems. Moreover, thanks to the synergistic flame-retardant effect between nitrogen and phosphorus elements, phosphorus compounds promote char formation, and nitrogen compounds promote foaming and expansion. Together, they form a dense, porous, expanded char layer, effectively isolating heat and oxygen transfer, thus achieving the goal of significantly improving the flame-retardant performance of PPO resin with only a small amount added. Unlike conventional flame retardants, which lead to dielectric property degradation when added in large quantities, the nitrogen-phosphorus flame retardant of this invention has minimal impact on the dielectric properties of the polyphenylene ether matrix when added in small amounts, and can maintain the original low dielectric properties of polyphenylene ether to the maximum extent while imparting flame retardancy. Attached Figure Description
[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 The image shows the infrared analysis test results of the crosslinking agent in the examples. Detailed Implementation
[0031] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.
[0032] The low molecular weight polyphenylene ether used in the following examples and comparative examples is double-bond-terminated low molecular weight polyphenylene ether SA9000.
[0033] Example 1
[0034] This embodiment provides a PPO resin for ultra-high frequency and high-speed printed circuit boards, which is made from a raw material comprising the following raw materials measured in parts by weight:
[0035] Low molecular weight polyphenylene ether: 82 parts;
[0036] Crosslinking agent: 3.5 parts;
[0037] Di-tert-butylperoxide isopropylbenzene: 0.1 parts;
[0038] Acetone: 60 parts;
[0039] The preparation method of the PPO resin includes the following steps:
[0040] Step 1: Mix low molecular weight polyphenylene ether, crosslinking agent and acetone to form a uniform mixture, then add bis-tert-butyl peroxide isopropylbenzene and mix until a uniform adhesive is formed;
[0041] Step 2: Immerse the fiberglass cloth fully in the adhesive solution, pull it out at a uniform speed after 15 seconds, and after it is completely dried at room temperature, transfer it to an oven and bake it at 150°C for 8 minutes to form a semi-cured sheet.
[0042] The third step is to rub the resin powder off the prepreg and pour it into a mold for hot pressing and curing to obtain PPO resin.
[0043] The preparation method of the crosslinking agent includes the following steps:
[0044] Step A: Under nitrogen protection, 653 mg of pentaerythritol triallyl ether was added to toluene and stirred until homogeneous. Then, 10 mg of dibutyltin dilaurate was added and mixed. Next, 269 mg of chloroethyl isocyanate was added in an ice-water bath. After the addition was complete, the ice bath was removed and the temperature was raised to 50°C at a controlled heating rate of 2°C / min. After stirring for 4 hours, the heating was stopped and the mixture was allowed to cool naturally. The mixture was then filtered to remove impurities. The filtrate was washed and dried with anhydrous sodium sulfate. The product was then separated by vacuum distillation to obtain the haloallyl ether derivative.
[0045] Step B: 586 mg of haloallyl ether derivative and 324.4 mg of 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide were added to N,N-dimethylformamide. Nitrogen gas was introduced for protection, and stirring was started. After mixing evenly, 249 mg of potassium carbonate was added. Then the temperature was raised to 90°C and stirring was continued for 9 hours. Heating was stopped, and the mixture was cooled to room temperature. The mixture was filtered to remove salt, and the crude product was collected by vacuum distillation. After washing, drying, recrystallization and purification, the crosslinking agent was obtained.
[0046] In the above technical solution, the isocyanate group in the chloroethyl isocyanate structure has high reactivity and can undergo a carbamate reaction with the active hydroxyl group in the pentaerythritol triallyl ether structure under mild conditions to obtain a haloallyl ether derivative. Then, under the action of an alkaline acid-binding agent, the halogen substituent in the haloallyl ether derivative structure can further undergo an etherification substitution reaction with the active hydroxyl group in the 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide structure to obtain a phosphorus-containing allyl ether derivative containing three equivalent unsaturated alkenyl substituents and containing nitrogen and phosphorus elements, i.e., a crosslinking agent.
[0047] Figure 1 This is the infrared analysis test pattern of the crosslinking agent, where 3326 cm⁻¹... -1 The characteristic absorption peak appearing at 3080 cm⁻¹ is attributed to the characteristic NH absorption peak of carbamates. -1The characteristic absorption peak appearing at 1719 cm⁻¹ is attributed to the characteristic absorption peak of CH in unsaturated carbon-carbon double bonds. -1 The characteristic absorption peak appearing at 1303 cm⁻¹ is attributed to the C=O characteristic absorption peak of carbamates. -1 The characteristic absorption peak appearing at 1032 cm⁻¹ belongs to the P=O characteristic absorption peak. -1 The characteristic absorption peaks appearing at this point are attributed to the CO characteristic absorption peaks of the ether bond, and no characteristic absorption peaks of hydroxyl and isocyanate groups were observed in the figure.
[0048] Example 2
[0049] This embodiment provides a PPO resin for ultra-high frequency and high-speed printed circuit boards, which is made from a raw material comprising the following raw materials measured in parts by weight:
[0050] Low molecular weight polyphenylene ether: 88 parts;
[0051] Crosslinking agent: 6.5 parts;
[0052] Di-tert-butylperoxide isopropylbenzene: 0.2 parts;
[0053] Acetone: 70 parts;
[0054] The preparation method of the PPO resin includes the following steps:
[0055] Step 1: Mix low molecular weight polyphenylene ether, crosslinking agent and acetone to form a uniform mixture, then add bis-tert-butyl peroxide isopropylbenzene and mix until a uniform adhesive is formed;
[0056] Step 2: Immerse the fiberglass cloth fully in the adhesive solution, pull it out at a uniform speed after 15 seconds, and after it is completely dried at room temperature, transfer it to an oven and bake it at 150°C for 8 minutes to form a semi-cured sheet.
[0057] The third step is to rub the resin powder off the prepreg and pour it into a mold for hot pressing and curing to obtain PPO resin.
[0058] The preparation method of the crosslinking agent is the same as that in Example 1.
[0059] Example 3
[0060] The PPO resin for ultra-high frequency and high-speed printed circuit boards is made from raw materials comprising the following ingredients in parts by weight:
[0061] Low molecular weight polyphenylene ether: 96 parts;
[0062] Crosslinking agent: 6.8 parts;
[0063] Di-tert-butylperoxide isopropylbenzene: 0.3 parts;
[0064] Acetone: 80 parts;
[0065] The preparation method of the PPO resin includes the following steps:
[0066] Step 1: Mix low molecular weight polyphenylene ether, crosslinking agent and acetone to form a uniform mixture, then add bis-tert-butyl peroxide isopropylbenzene and mix until a uniform adhesive is formed;
[0067] Step 2: Immerse the fiberglass cloth fully in the adhesive solution, pull it out at a uniform speed after 15 seconds, and after it is completely dried at room temperature, transfer it to an oven and bake it at 150°C for 8 minutes to form a semi-cured sheet.
[0068] The third step is to rub the resin powder off the prepreg and pour it into a mold for hot pressing and curing to obtain PPO resin.
[0069] The preparation method of the crosslinking agent is the same as that in Example 1.
[0070] Comparative Example 1
[0071] The difference between this comparative example and Example 2 is that the crosslinking agent is replaced with pentaerythritol triallyl ether, otherwise they are the same.
[0072] Comparative Example 2:
[0073] The difference between this comparative example and Example 2 is that the crosslinking agent is replaced with 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide, all other aspects are the same.
[0074] The performance of the PPO resins provided in the above embodiments and comparative examples was tested using the following methods:
[0075] (1) Using a vector network analyzer and a split column dielectric resonator, the dielectric constant and dielectric loss were tested at 10 GHz, 50% relative humidity and room temperature. Before the test, each sample with a thickness of about 0.4 mm was dried in an oven at 110 °C for 1 h, and then cooled to room temperature in a desiccator for 30 min before the test.
[0076] (2) According to standard GB / T 2406.2-2009, after the resin is placed at room temperature for 2 months, the limiting oxygen index test is carried out;
[0077] The performance test data above are shown in Table 1.
[0078] Table 1 Performance Test Results
[0079] Dielectric constant (F / m) Dielectric loss Oxygen index (%) Example 1 2.60 0.0015 28.6 Example 2 2.62 0.0018 29.1 Example 3 2.61 0.0017 28.9 Comparative Example 1 2.89 0.0024 19.8 Comparative Example 2 2.98 0.0020 27.2
[0080] The test results above show that the PPO resin in this embodiment of the invention can maintain low dielectric properties while exhibiting excellent flame retardant performance. Replacing the crosslinking agent with the conventional crosslinking agent pentaerythritol triallyl ether results in a deterioration in the dielectric properties of the PPO resin due to the presence of polar groups in pentaerythritol triallyl ether. Furthermore, the flame retardant performance is significantly reduced due to the absence of nitrogen and phosphorus synergistic flame retardant elements. Replacing the crosslinking agent with 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide results in an uncrosslinked PPO resin, leading to a decrease in dielectric properties. Moreover, the resin's flame retardant performance is also reduced due to migration during storage and the absence of nitrogen elements for synergistic flame retardancy.
[0081] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.
Claims
1. A PPO resin for ultra-high frequency and high-speed printed circuit boards, characterized in that, Made from raw materials comprising the following ingredients measured in parts by weight: Low molecular weight polyphenylene ether: 82-96 parts; Crosslinking agent: 1.5-3.2 parts; Initiator: 0.1-0.3 parts; Organic solvent: 60-80 parts; The crosslinking agent is a phosphorus allyl ether derivative in its structure.
2. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 1, characterized in that, The preparation method of the PPO resin includes the following steps: Step 1: Mix low molecular weight polyphenylene ether, crosslinking agent and organic solvent to form a homogeneous mixture, then add initiator and mix until a homogeneous adhesive is formed; Step 2: Immerse the fiberglass cloth fully in the adhesive solution, pull it out at a uniform speed after 15 seconds, and after it is completely dried at room temperature, transfer it to an oven and bake it at a temperature of 140-150℃ for 5-10 minutes to form a semi-cured sheet. The third step is to rub resin powder off the prepreg and pour it into a mold for hot pressing and curing to obtain PPO resin.
3. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 1, characterized in that, The preparation method of the crosslinking agent includes the following steps: Step A: Under nitrogen protection, pentaerythritol triallyl ether is added to toluene and stirred until homogeneous. Then, catalyst is added and mixed. Next, halogen-modifying reagent is added in an ice-water bath. After the addition is complete, the ice bath is removed and the temperature is raised to 40-50℃ at a rate of 1-2℃ / min. After stirring for 4-6 hours, heating is stopped and the mixture is allowed to cool naturally. The mixture is then filtered to remove impurities. The filtrate is washed, dried with anhydrous sodium sulfate, and the product is separated by vacuum distillation to obtain the haloallyl ether derivative. Step B: Add the haloallyl ether derivative and 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide to N,N-dimethylformamide, purge with nitrogen for protection, start stirring, and mix thoroughly. Then add an alkaline acid-binding agent, raise the temperature to 80-100℃, and continue stirring for 6-12 hours. Stop heating, cool to room temperature, filter to remove salt, collect the crude product by vacuum distillation, and purify by washing, drying, and recrystallization to obtain the crosslinking agent.
4. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 3, characterized in that, In step A, the molar ratio of pentaerythritol triallyl ether to halogen-modifying reagent is 1:
1.
5. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 3, characterized in that, In step A, the catalyst is any one of dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, methyl tin mercaptan, or octyl tin mercaptan.
6. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 3, characterized in that, In step A, the halogen modifying agent is any one of chloroethyl isocyanate, 3-chloropropyl isocyanate, or ethyl 2-bromoisocyanate.
7. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 3, characterized in that, In step B, the molar ratio of the haloallyl ether derivative and 2,6,7-trioxa-1-phosphabicyclo(2.2.2)octane-4-methanol-1-oxide is 1:
1.
8. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 3, characterized in that, In step B, the alkaline acid-binding agent is potassium carbonate.
9. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 1, characterized in that, The initiator is bis(tert-butylperoxyisopropylbenzene).
10. The PPO resin for ultra-high frequency and high-speed printed circuit boards according to claim 1, characterized in that, The organic solvent is acetone.