Resin composition and metal foil layer substrate

Abstract

A resin composition and a metal foil layer substrate are disclosed. The resin composition includes 20 to 40 parts by weight of an epoxy resin, 40 to 60 parts by weight of a modified benzoxazine resin, 2 to 10 parts by weight of a maleimide resin, and 25 to 50 parts by weight of a filler. The modified benzoxazine resin has a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group. The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group accounts for 10 to 20 percent by weight based on a total weight of the modified benzoxazine resin, which is 100 percent by weight.

Description

Technical Field

[0001] This invention relates to a resin composition and a metal foil layer substrate, and more particularly to a resin composition and a metal foil layer substrate that does not release oily substances at high temperatures. Background Technology

[0002] Benzooxazine resin is a thermosetting resin with a structure similar to phenolic resin, and its properties are superior to those of traditional phenolic resins. For example, benzooxazine resin has low moisture absorption and good mechanical and dielectric properties.

[0003] During the curing process, benzoxazine resin does not release small-molecule byproducts, and the volume shrinkage rate after curing is low. Therefore, benzoxazine resin has a wide range of applications and can be blended with other types of resins, especially for the fabrication of metal foil substrates.

[0004] DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) is a flame retardant with excellent heat resistance and flame retardancy. Furthermore, DOPO flame retardant can be blended with other thermosetting resins, inorganic fillers, or fibers to form composite materials. Therefore, in the prior art, this composite material is commonly used to fabricate metal foil substrates.

[0005] However, under high-temperature conditions, DOPO flame retardant will thermally decompose into phosphoric acid, metaphosphoric acid, or pyrophosphoric acid, which are phosphoric acid-containing compounds. These phosphoric acid-containing compounds readily react with copper and release an oily substance onto the surface of the metal foil substrate, thus affecting the quality of the metal foil substrate.

[0006] Therefore, how to improve the heat resistance and flame retardancy of composite materials by modifying the composition while preventing oily substances from surfacing has become one of the important issues that this project aims to solve. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a resin composition and a metal foil substrate to address the shortcomings of the prior art.

[0008] To address the aforementioned technical problems, one technical solution adopted by the present invention is to provide a resin composition. The resin composition comprises: 20 to 40 parts by weight of epoxy resin, 40 to 60 parts by weight of modified benzoxazine resin, 2 to 10 parts by weight of maleimide resin, and 25 to 50 parts by weight of filler. The modified benzoxazine resin has a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group. Based on 100% by weight of the total weight of the modified benzoxazine resin, the proportion of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10 to 20% by weight.

[0009] Preferably, the phosphorus atom content in the modified benzoxazine resin is 1 to 2% by weight.

[0010] Preferably, the modified benzoxazine resin is formed by reacting a DOPO-containing compound, a diisocyanate compound, and a benzoxazine resin.

[0011] Preferably, the DOPO-containing compound is grafted onto the main chain of the benzoxazine resin via a diisocyanate compound.

[0012] Preferably, the phosphorus atom content in the DOPO-containing compound is 12 to 20% by weight.

[0013] Preferably, the DOPO-containing compound is as shown in formula (I):

[0014]

[0015] Preferably, the diisocyanate compound is selected from the group consisting of isophorone diisocyanate, 4,4′-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and combinations thereof.

[0016] Preferably, the benzoxazine resin is a bisphenol A modified benzoxazine resin, a bisphenol F modified benzoxazine resin, a diamine modified benzoxazine resin, or a combination thereof.

[0017] Preferably, the modified benzoxazine resin has the substituents shown in formula (II):

[0018]

[0019] To address the aforementioned technical problems, another technical solution adopted by the present invention is to provide a metal foil layer substrate. The metal foil layer substrate includes a metal substrate, a cured product, and a printed circuit board. The cured product is formed on the metal substrate, and the printed circuit board is formed on the cured product. The resin composition includes: 20 to 40 parts by weight of epoxy resin, 40 to 60 parts by weight of modified benzoxazine resin, 2 to 10 parts by weight of maleimide resin, and 25 to 50 parts by weight of filler. The modified benzoxazine resin has a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group. Based on 100% by weight of the total weight of the modified benzoxazine resin, the proportion of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10 to 20% by weight.

[0020] One of the beneficial effects of the present invention is that the resin composition and metal foil substrate provided by the present invention can achieve the effect of preventing oily substances from floating out by means of the technical solution that "the resin composition includes 40 to 60 parts by weight of modified benzoxazine resin", "the modified benzoxazine resin has 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group" and "the proportion of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10 to 20% by weight".

[0021] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the steps involved in synthesizing the modified benzoxazine resin according to the present invention.

[0023] Figure 2 This is a schematic diagram illustrating the manufacturing process of the cured product of the present invention.

[0024] Figure 3 This is a flowchart of the manufacturing method of the cured product of the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the manufacturing process of the metal foil substrate of the present invention.

[0026] Figure 5 This is a flowchart illustrating the steps of the method for manufacturing the metal foil substrate of the present invention. Detailed Implementation

[0027] The following specific examples illustrate the embodiments of the "resin composition and metal foil substrate" disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention. In addition, the term "or" as used herein may include, depending on the actual situation, any combination of any one or more of the associated listed items.

[0028] The cured product and metal foil substrate of the present invention are made using a resin composition. The cured product formed by the resin composition has good heat resistance and does not release oily substances under high temperature conditions, and can be used as one of the manufacturing materials for metal foil substrates.

[0029] In this invention, the resin composition comprises 20 to 40 parts by weight of an epoxy resin, 40 to 60 parts by weight of a modified benzoxazine resin, 2 to 10 parts by weight of a maleimide resin, and 25 to 50 parts by weight of a filler. Thus, the resin composition and metal foil substrate of this invention possess excellent heat resistance and flame retardancy, and do not release oily substances at high temperatures.

[0030] It is worth noting that the modified benzoxazine resin added in this invention has a DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) group. Thus, the addition of the modified benzoxazine resin can improve the heat resistance and flame retardancy of the resin composition and the metal foil substrate, thereby enhancing the properties of the metal foil substrate.

[0031] Specifically, based on 100% by weight of the total weight of the modified benzoxazine resin, the proportion of DOPO groups in the modified benzoxazine resin is 10% to 20% by weight. In some embodiments, the proportion of DOPO groups in the modified benzoxazine resin can be 12%, 14%, 16%, or 18% by weight. Preferably, the proportion of DOPO groups in the modified benzoxazine resin is 15% to 19% by weight.

[0032] To ensure good heat resistance and flame retardancy of the resin composition and the metal foil substrate, the phosphorus content in the modified benzoxazine resin is 1% to 2% by weight, with the total weight of the modified benzoxazine resin being 100% by weight. Preferably, the phosphorus content in the modified benzoxazine resin is 1.1% to 1.5% by weight.

[0033] In one exemplary embodiment, the modified benzoxazine resin is formed by reacting a DOPO-containing compound, a diisocyanate compound, and a benzoxazine resin.

[0034] In the molecular structure of the modified benzoxazine resin, the DOPO-containing compound is grafted onto the main chain of the benzoxazine resin via a diisocyanate compound. That is, the two isocyanate groups of the diisocyanate compound are respectively bonded to the DOPO-containing compound and the benzoxazine resin.

[0035] Specifically, the phosphorus atom content in the DOPO-containing compound is 6% to 12% by weight. In one exemplary embodiment, the DOPO-containing compound is shown in formula (I):

[0036]

[0037] The diisocyanate compounds are aliphatic diisocyanates with a weight-average molecular weight of 150 g / mol to 280 g / mol. Selecting diisocyanate compounds within this molecular weight range is beneficial for the grafting reaction. Specifically, the diisocyanate compounds can be selected from the group consisting of isophorone diisocyanate, 4,4′-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and combinations thereof. However, the invention is not limited thereto.

[0038] As previously mentioned, DOPO-containing compounds can be grafted onto benzoxazine resins via a reaction with the isocyanate group of a diisocyanate compound. Therefore, the DOPO-containing compound shown in formula (I), upon reaction with the diisocyanate compound, will form substituents as shown in formula (II). In other words, the modified benzoxazine resin can have the substituents shown in formula (II):

[0039]

[0040] In this invention, the type of benzoxazine resin used is not limited; any resin containing a DOPO group is considered a modified benzoxazine resin of this invention. For example, the benzoxazine resin may be a bisphenol A type benzoxazine resin, a bisphenol F type benzoxazine resin, a diamine type benzoxazine resin, or a combination thereof.

[0041] In one exemplary embodiment, when the benzoxazine resin is a bisphenol A type modified benzoxazine resin and is grafted with the substituents shown in formula (II) above, the modified benzoxazine resin can be represented as shown in formula (III):

[0042]

[0043] In equation (III), It is formed by grafting diisocyanate compounds and varies depending on the type of diisocyanate compound used.

[0044] In equation (III), It is formed by the reaction of primary aniline and varies depending on the type of primary aniline used. The amino group in primary aniline can be located at the end of the molecule or grafted onto the side chain. In addition to the amino group, primary aniline can also have other substituents, such as alkyl, halogen, or hydrogen atoms. Specifically, primary aniline can be selected from the following group: aniline, 4-methylaniline, 4-bromoaniline, and 4-isopropylaniline.

[0045] For the specific synthesis steps of the modified benzoxazine resin, please refer to [link / reference needed]. Figure 1 As shown.

[0046] First, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is dissolved in a solvent, and maleic anhydride is added to react and form a DOPO-containing compound (step S1). The DOPO-containing compound is added to the benzoxazine resin and heated to dissolve at a temperature of 55°C to 95°C to form a reactant solution (step S2). Next, diisocyanate is added to the reactant solution and reacted at a temperature of 120°C to 140°C to generate a modified benzoxazine resin (step S3).

[0047] The following synthesis example 1 illustrates the synthesis method of the DOPO-containing compound (corresponding to step S1 above). The following synthesis examples 2-1 to 2-6 illustrate the synthesis method of the modified benzoxazine resin of samples 1 to 6 (corresponding to steps S2 and S3 above).

[0048] [Synthesis example 1]

[0049] A heating device, thermometer, stirrer, cooling pipe, and nitrogen inlet pipe were installed on a 3-liter separable reaction flask. 400 mL of toluene and 400 mL of tetrahydrofuran (solvent) were added to the separable reaction flask. 216 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to the separable reaction flask and stirred at 80°C until completely dissolved.

[0050] Next, under nitrogen purging, 98 grams of maleic anhydride were gradually added over 60 minutes. The mixture was then heated to the solvent's reflux temperature and reacted at that temperature for 6 hours.

[0051] After the reaction is complete and the temperature is lowered to room temperature, the compound containing the DOPO group (DOPO-MAH) is obtained by filtration, washing, and drying, as shown in formula (I) above. Specifically, 400 grams of a tetrahydrofuran / ethanol mixture in a volume ratio of 1:1 is used when washing the DOPO-containing compound.

[0052] [Synthetic Examples 2-1 to 2-6]

[0053] 200 g of benzoxazine resin and 600 g of toluene were added to a separable reaction flask and stirred uniformly at 50°C to 70°C until dissolved. While stirring, the DOPO-containing compound (DOPO-MAH) prepared in Synthesis Example 1 was gradually added over 20 minutes, and the mixture was heated to 55°C to 95°C to dissolve, forming a reactant solution. Next, a diisocyanate compound was added to the reactant solution, and the mixture was reacted at 120°C to 140°C for 1 hour to generate the modified benzoxazine resin of the present invention.

[0054] Table 1 lists the types and quantities of DOPO-based compounds, diisocyanate compounds, and benzoxazine resins used in Synthetic Examples 2-1 to 2-6. The diisocyanate can be isophorone diisocyanate (IPDI), methylene dicyclohexyl diisocyanate (HMDI), hexamethylene diisocyanate (HDI), or combinations thereof. The benzoxazine resin can be bisphenol A type benzoxazine resin (BPA-BZ), bisphenol F type benzoxazine resin (BPF-BZ), or diamine type benzoxazine resin (ODA-BZ, MDA-BZ).

[0055] Table 1

[0056]

[0057] For a schematic diagram of the solidified material manufacturing process, please refer to [link / reference]. Figure 2 As shown.

[0058] First, a resin composition comprising the aforementioned modified benzoxazine resin is prepared, and the resin composition is coated onto a metal substrate 10 to form a resin film 20. Next, the resin film 20 is cured at a temperature of 70°C to 200°C to form a semi-cured film 20'. After hot pressing, the semi-cured film 20' yields a cured product 20.

[0059] For detailed manufacturing steps of the cured product, please refer to [link / reference]. Figure 3 As shown.

[0060] A resin composition is prepared, comprising a modified benzoxazine resin, an epoxy resin, a maleimide resin, and a filler (step S4). The resin composition is coated onto a metal substrate (step S5). The resin composition is cured at a temperature of 70°C to 200°C to form a semi-cured film (step S6). The semi-cured film is hot-pressed to form a cured product (step S7).

[0061] For a schematic diagram of the metal foil substrate manufacturing process, please refer to [link / reference]. Figure 4 As shown.

[0062] First, a resin composition comprising the aforementioned modified benzoxazine resin is prepared, and the resin composition is coated onto a metal substrate 10 to form a resin film 20. Next, the resin film 20 is cured at a temperature of 70°C to 200°C to form a semi-cured film 20'. A printed circuit board 30 is placed on the semi-cured film 20' and hot-pressed to form a cured product 20', thus obtaining a metal foil substrate.

[0063] For detailed manufacturing steps of the metal foil substrate, please refer to [link / reference needed]. Figure 5 As shown.

[0064] Steps S4 to S6 in the manufacturing process of the metal foil substrate are the same as steps S4 to S6 in the manufacturing process of the cured material, and therefore will not be described again here. After forming the semi-cured film (step S6), a printed circuit board is placed on the semi-cured film to form a laminated structure (step S7'). The laminated structure is hot-pressed to form a cured material from the semi-cured film, and the metal foil substrate is obtained (step S8').

[0065] Regardless of the manufacturing method of the aforementioned cured product or metal foil substrate, the resin composition forms a cured product after curing and hot pressing. Because this invention controls the proportion of DOPO groups in the modified benzoxazine resin, the heat resistance and flame retardancy of the cured product can be improved by adding an appropriate amount of phosphorus atoms.

[0066] To illustrate the advantages of the cured product and the metal foil substrate of the present invention, metal foil substrates of Examples 1 to 6 (E1 to E6) and Comparative Examples 1 to 4 (C1 to C4) were manufactured according to the steps described above.

[0067] The resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4 contain different types and amounts of resin (see Table 2 for specific components and contents) to compare the effects of different resin compositions on the properties of the metal foil substrate. The difference between Examples 1 to 6 and Comparative Examples 1 to 4 is that the benzoxazine resins (BPA-BZ, ODA-BZ) added in Comparative Examples 1 to 4 are unmodified and do not have DOPO groups.

[0068] [Examples 1 to 6]

[0069] Examples 1 to 6 (E1 to E6) were prepared by adding at least one of the modified benzoxazine resins and maleimide resins from samples 1 to 6 to 40 grams of solvent (butanone) according to the component contents listed in Table 2, and allowing them to dissolve completely. Next, epoxy resins (ortho-methylphenolic epoxy resin (CNE epoxy), bisphenol A phenolic epoxy resin (BNE epoxy), and bisphenol A type epoxy resin (BPA epoxy)), toughening agent (liquid polybutadiene), and flame retardant were added, and the mixture was homogenized and dissolved using a homogenizer. After complete dissolution, filler (silica) was added, and the mixture was continuously stirred and dispersed using a homogenizer to complete the preparation of the resin composition.

[0070] Type E glass substrate (model: E 2116) is immersed in the resin composition and baked at 80°C for 3 minutes, followed by baking at 180°C for 7 minutes. After drying, a semi-cured film is obtained. Four semi-cured films are laminated together, and a metal layer is placed on each side of the laminated structure to form a laminated structure. The laminated structure is then sent to a hot press for hot pressing and curing. The hot press settings are as follows: the temperature is increased to 200°C to 220°C at a rate of 3.0°C per minute, and hot-pressed for 180 minutes at a temperature of 200°C to 220°C and a pressure of 15 kg / cm² (initial pressure 8 kg / cm²) to obtain the metal foil layer substrate.

[0071] [Feature Testing]

[0072] Transition glass temperature (Tg): The glass transition temperature of the metal foil substrate is measured using a thermomechanical analyzer (TMA).

[0073] Coefficient of thermal expansion (CTE): According to the IPC-TM-6502.4.24.5 specification, the coefficient of thermal expansion (z-CTE) of the metal foil substrate in the z-axis direction is measured by a thermomechanical analyzer in the temperature range of 50℃ to 260℃.

[0074] Peel strength: First, dry the metal foil substrate, then measure the amount of external force required to vertically tear a 1 / 8-inch wide copper foil (metal substrate) to quantify the peel strength of the metal foil substrate.

[0075] Heat resistance: First, dry the metal foil substrate, then immerse it in a 300°C solder bath for 100 seconds, and repeat the immersion 3 times. If there is no change in the appearance of the metal foil substrate, it is indicated by "○". If there are blistering or protrusions on the appearance of the metal foil substrate, it is indicated by "×".

[0076] Flame Retardancy (Flaming Test, UL94): According to the UL94 flame retardancy test standard, the flame retardancy rating of plastic materials is determined by measuring the auto-ignition time, auto-ignition rate, and the state of falling particles after a standard plastic material specimen is burned in a flame using the vertical burning method. The flame retardancy ratings are ranked from best to worst as HB, V-2, V-1, V-0, and 5V, with 5V being the highest. In the UL94 test method, the plastic material is burned vertically in a flame, with each test cycle lasting ten seconds. The steps are as follows: Step 1: Place the specimen in the flame for ten seconds and then remove it, measuring the burning time (T1). Step 2: After the flame extinguishes, place the specimen back in the flame for ten seconds and remove it, measuring the burning time again (T2). Step 3: Repeat the experiment several times and take the average value. Step 4: Calculate the sum of T1 and T2. The requirements for V-0 level are: the average of T1 and the average of T2 must not exceed 10 seconds, and the total of T1 and T2 must not exceed 50 seconds.

[0077] Oily substance floating test: Cut the metal foil substrate into square samples with a side length of 10 cm. After baking in an oven at 200℃ for 120 minutes, observe whether any oily substance floats to the surface.

[0078]

[0079]

[0080] As shown in Table 2, compared with Comparative Examples 1 to 4, the addition of the modified benzoxazine resin of the present invention can improve the heat resistance and flame retardancy of the metal foil substrate, and can prevent oily substances from floating out in a high-temperature environment, thereby improving the quality of the metal foil substrate.

[0081] Furthermore, the metal foil substrate of the present invention exhibits excellent heat resistance and flame retardancy. Specifically, the glass transition temperature of the metal foil substrate is 170°C to 185°C, and the coefficient of thermal expansion in the z-direction is 2.5% to 3.0%. Therefore, the metal foil substrate can withstand higher processing temperatures.

[0082] As shown in Table 2, the epoxy resin of the present invention may include cresolnovolac epoxy resin (CNE resin), bisphenol A novolac epoxy resin (BNE resin), and bisphenol A type epoxy resin. With the total weight of the epoxy resin as 100% by weight, the content of cresolnovolac epoxy resin is 30% to 35% by weight, the content of bisphenol A novolac epoxy resin is 30% to 35% by weight, and the content of bisphenol A type epoxy resin is 30% to 35% by weight.

[0083] [Beneficial Effects of the Examples]

[0084] One of the beneficial effects of the present invention is that the resin composition and metal foil substrate provided by the present invention can achieve the effect of preventing oily substances from floating out by means of the technical solution that "the resin composition includes 40 to 60 parts by weight of modified benzoxazine resin", "the modified benzoxazine resin has 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group" and "the proportion of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10 to 20% by weight".

[0085] Furthermore, the present invention uses technical solutions such as "the modified benzoxazine resin is formed by reacting a DOPO-containing compound, a diisocyanate compound, and a benzoxazine resin" or "a DOPO-containing compound is grafted onto the main chain of the benzoxazine resin via a diisocyanate compound" to obtain the modified benzoxazine resin of the present invention, thereby achieving the effect of preventing oily substances from floating out.

[0086] Furthermore, the present invention achieves the effect of improving the heat resistance and flame retardancy of the resin composition and the metal foil substrate by using the technical solution of "the phosphorus atom content in the modified benzoxazine resin is 1% to 2% by weight" or "the phosphorus atom content in the DOPO-containing compound is 12% to 20% by weight".

[0087] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the claims of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the claims of the present invention.

Claims

1. A resin composition, characterized in that, The resin composition includes: 20 to 40 parts by weight of an epoxy resin; 40 to 60 parts by weight of a modified benzoxazine resin, wherein the modified benzoxazine resin has a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group; wherein, based on 100% by weight of the total weight of the modified benzoxazine resin, the proportion of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10% to 20% by weight. 2 to 10 parts by weight of maleimide resin; and 25 to 50 parts by weight of filler; The modified benzoxazine resin is formed by reacting a DOPO-containing compound, a diisocyanate compound, and a benzoxazine resin. The DOPO-containing compound is shown in formula (I). Formula (I).

2. The resin composition according to claim 1, characterized in that, The modified benzoxazine resin contains 1 to 2% phosphorus atoms by weight.

3. The resin composition according to claim 1, characterized in that, The DOPO-containing compound is grafted onto the main chain of the benzoxazine resin via the diisocyanate compound.

4. The resin composition according to claim 1, characterized in that, The phosphorus content in the DOPO-containing compound is 12% to 20% by weight.

5. The resin composition according to claim 1, characterized in that, The diisocyanate compound is selected from the group consisting of isophorone diisocyanate, 4,4′-diisocyanate dicyclohexylmethane, hexamethylene diisocyanate, and combinations thereof.

6. The resin composition according to claim 1, characterized in that, The benzoxazine resin is a bisphenol A modified benzoxazine resin, a bisphenol F modified benzoxazine resin, a diamine modified benzoxazine resin, or a combination thereof.

7. A metal foil layer substrate, characterized in that, The metal foil substrate includes: A metal substrate; A cured product formed on the metal substrate, the cured product being formed by curing a resin composition; wherein the resin composition comprises: 20 to 40 parts by weight of an epoxy resin, 40 to 60 parts by weight of a modified benzoxazine resin, 2 to 10 parts by weight of a maleimide resin, and 25 to 50 parts by weight of a filler; wherein the modified benzoxazine resin has a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group, and the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group accounts for 100% by weight of the total weight of the modified benzoxazine resin, and the percentage of the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide group is 10% to 20% by weight; and A printed circuit board is formed on the cured material; The modified benzoxazine resin is formed by reacting a DOPO-containing compound, a diisocyanate compound, and a benzoxazine resin. The DOPO-containing compound is shown in formula (I). Formula (I).

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