TWI901471B - Resin composition, and prepreg and metal-clad laminate using the same - Google Patents

Abstract

A resin composition, and a prepreg and a metal-clad laminate using the same are provided. The resin composition includes (A) a modified PPE resin represented by the following Chemical Formula 1, (B) a bismaleimide resin, (C) a liquid rubber resin, (D) a catalyst, (E) a cross-linking agent, (F) spherical silicon dioxide, (G) a halogen-free flame retardant, and (H) a siloxane coupling agent.

Description

Resin composition, prepreg containing the same, and metal-clad laminate

The present invention relates to a resin composition, and more particularly to a resin composition for producing a prepreg and a metal-clad laminate having low dielectric dissipation factor (Df), high peel resistance, and a high glass transition temperature (Tg).

In recent years, with the development of fifth-generation mobile networks (5G), copper-clad laminate materials have been striving to develop lower dielectric properties to facilitate future high-frequency and fast transmission applications.

Currently used low-k dielectric formulations all incorporate a certain percentage of liquid rubber. Liquid rubber, with its low molecular weight, high solubility, and multi-reactive groups, is ideal for high-frequency and high-speed substrates. However, the addition of liquid rubber can degrade other performance characteristics, such as glass transition temperature (Tg) and peel force.

Based on the above, the development of a low-dielectric resin composition for the preparation of copper-clad laminate materials with ultra-low dielectric dissipation factor (Df), high peel resistance, low water absorption, and high glass transition temperature (Tg) is a goal that technicians in this field are eager to develop.

The present invention provides a resin composition that simultaneously has low dielectric loss, low water absorption, high heat resistance, high peeling resistance and high glass transition temperature.

The present invention provides a resin composition comprising (A) a modified polyphenylene ether resin having a chemical structure represented by the following Chemical Formula 1; (B) a bismaleimide resin; (C) a liquid rubber resin; (D) a catalyst; (E) a crosslinking agent; (F) spherical silica; (G) a halogen-free flame retardant; and (H) a siloxane coupling agent. [Chemical Formula 1] In Chemical Formula 1, R may be a bisphenol structure, and n may be an integer from 2 to 30, preferably an integer from 15 to 20.

In one embodiment of the present invention, the above R is a chemical structure represented by any one of the following Chemical Formulas 2 to 5: [Chemical Formula 2] [Chemical formula 3] [Chemical formula 4] [Chemical formula 5] In Chemical Formulas 2 to 5, * indicates a position where the unit can be linked to another unit.

In one embodiment of the present invention, based on the total weight of the resin composition, the resin composition comprises: 10 wt % to 50 wt % of the (A) modified polyphenylene ether resin; 10 wt % to 50 wt % of the (B) bismaleimide resin; 5 wt % to 45 wt % of the (C) liquid rubber resin; 5 wt % to 45 wt % of the (E) crosslinking agent; 25 wt % to 65 wt % of the (F) spherical silica; and 5 wt % to 45 wt % of the (G) halogen-free flame retardant; Based on 100 parts by weight of the resin composition, the resin composition further comprises: 0.1 1 to 5 phr of the catalyst (D); and 0.1 to 5 phr of the siloxane coupling agent (H).

In one embodiment of the present invention, the crosslinking agent (E) includes triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethallyl isocyanurate (TMAIC), diallyl phthalate, divinylbenzene, 1,2,4-Triallyl trimellitate, or a combination thereof.

In one embodiment of the present invention, the halogen-free flame retardant (G) includes a phosphorus-based flame retardant, and the phosphorus-based flame retardant includes triphenyl phosphate (TPP), tris(2-chloroethyl) phosphate (TCEP), triphenyl phosphate (TBP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), red phosphorus, phosphorus pentoxide, aminophosphates, ammonium phosphates, ammonium polyphosphate, aluminum diethylphosphinate, or a combination thereof.

In one embodiment of the present invention, the average particle size (D50) of the (F) spherical silica is 2.0 μm to 3.0 μm.

In one embodiment of the present invention, the (C) liquid rubber resin has a number average molecular weight (Mn) of 1000 g/mol to 5000 g/mol and has 10 wt % to 90 wt % of 1,2-vinyl groups.

In one embodiment of the present invention, the (H) siloxane coupling agent includes an aminosilane compound, an epoxysilane compound, a vinylsilane compound, an estersilane compound, a hydroxysilane compound, an isocyanatesilane compound, a methacryloxysilane compound, an acryloxysilane compound, or a combination thereof.

The present invention also provides a prepreg comprising the above-mentioned resin composition and a fiber substrate.

The present invention also provides a metal clad laminate comprising the above-mentioned prepreg and metal foil.

Based on the above, the resin composition of the present invention, through the use of a modified polyphenylene ether resin, can effectively increase the glass transition temperature of the resulting metal-clad laminate to above 200°C, improve the peeling resistance to above 5 lb/in, and simultaneously enable the metal-clad laminate to have a dielectric loss factor below 0.0035 and a water absorption rate below 0.200%.

In order to make the above features and advantages of the present invention more clearly understood, the following embodiments are specifically cited and described in detail as follows.

The following are examples that describe the present invention in detail. The implementation details provided in these examples are for illustrative purposes only and are not intended to limit the scope of protection for the present invention. Anyone skilled in the art will be able to modify or alter these implementation details based on the needs of actual implementation.

In this document, the range expressed as "a value to another value" is a summary expression method that avoids listing all the values within the range one by one in the specification. Therefore, the description of a specific numerical range covers any numerical value within the numerical range and the smaller numerical range defined by any numerical value within the numerical range, just as if the arbitrary numerical value and the smaller numerical range were written in the specification text. < Resin composition >

The present invention provides a resin composition comprising (A) a modified polyphenylene ether resin; (B) a dimaleimide resin; (C) a liquid rubber resin; (D) a catalyst; (E) a crosslinking agent; (F) spherical silica; (G) a halogen-free flame retardant; and (H) a siloxane coupling agent. The resin composition of the present invention may further include other additives as needed. The following describes each of the aforementioned components in detail.

（ A ) Modified polyphenylene ether resin

(A) Modified polyphenylene ether resin is a polyphenylene ether resin modified with bismaleimide (BMI), and its chemical structure can be represented by the following chemical formula 1: [Chemical formula 1] In Chemical Formula 1, R may be a bisphenol structure, and n may be an integer from 2 to 30, preferably an integer from 15 to 20.

In some embodiments, R may be a chemical structure represented by any one of the following Chemical Formulas 2 to 5: [Chemical Formula 2] [Chemical formula 3] [Chemical formula 4] [Chemical formula 5] In Chemical Formulas 2 to 5, * indicates a position where the unit can be linked to another unit.

In some embodiments, the number average molecular weight (Mn) of the modified polyphenylene ether resin (A) may be about 500 to 5000 g/mol, preferably 1200 to 2800 g/mol, for example, about 2200 g/mol, but the present invention is not limited to the above examples.

In some embodiments, the content of the modified polyphenylene ether resin (A) may be approximately 10 wt % to 50 wt %, preferably approximately 20 wt % to 35 wt %, based on the total weight of the resin composition. If the amount of the modified polyphenylene ether resin (A) exceeds this range, the dielectric dissipation factor (Df) and dielectric constant (Dk) of the resin composition may increase, resulting in poor electrical properties. If the amount of the modified polyphenylene ether resin (A) is below this range, the glass transition temperature of the resin composition may not be effectively increased.

When polyphenylene ether resin is modified with bismaleimide and possesses a bisphenol structure represented by any of Formulas 2 to 5, the resulting resin composition exhibits excellent peeling resistance, a high glass transition temperature, high flame resistance, low water absorption, and a low dielectric dissipation factor (Df) and dielectric constant (Dk). Specifically, when the bisphenol structure represented by R contains methyl or ethyl groups, water absorption is further reduced.

（ B ) Bismaleimide resin

(B) There are no specific restrictions on the bismaleimide resin; an appropriate bismaleimide resin can be selected based on the application. Bismaleimide resins can increase the glass transition temperature of the resin composition. In this embodiment, the bismaleimide resin may include: 4,4'-Diphenylmethane bismaleimide (KI Chemicals, Japan), Bis-(3-ethyl-5-methyl-4-maleimidophenyl)methane (KI Chemicals, Japan), 2,2-Bis-[4-(4-maleimidophenoxy)phenyl]propane (KI Chemicals, Japan), MIR-3000-70MT (Nippon Kayaku), BMI-3000J (Designer Molecules Inc.), BMI-689 (Designer Molecules Inc.), combinations thereof, or other suitable bismaleimide resins.

In some embodiments, the content of the (B) bismaleimide resin may be about 10 wt % to 50 wt %, preferably about 15 wt % to 25 wt %, based on the total weight of the resin composition.

（ C ) Liquid rubber resin

The (C) liquid rubber resin has low molecular weight, high solubility, and multiple reactive groups, which can reduce the dielectric dissipation factor (Df) and dielectric constant (Dk) of the resin composition. In this embodiment, the (C) liquid rubber resin can have a number average molecular weight (Mn) of 1000 g/mol to 5000 g/mol, preferably approximately 2500 g/mol to 4000 g/mol, and contain 10 wt % to 90 wt % of 1,2-vinyl groups, for example, approximately 80 wt % to 90 wt % of 1,2-vinyl groups.

In some embodiments, the content of the liquid rubber resin (C) may be approximately 5 wt % to 45 wt %, preferably approximately 10 wt % to 25 wt %, based on the total weight of the resin composition. If the amount of the liquid rubber resin (C) added exceeds this range, the glass transition temperature of the resin composition may be excessively lowered, failing to meet product requirements. Furthermore, excessive amounts of the liquid rubber resin (C) may be incompatible with the bismaleimide resin (B). If the amount of the liquid rubber resin (C) added is less than this range, the dielectric dissipation factor (Df) and dielectric constant (Dk) of the resin composition may not be effectively reduced, resulting in poor electrical properties.

In some embodiments, (C) the liquid rubber resin may be selected from: B-1000 (Japan Soda), B-2000 (Japan Soda), B-3000 (Japan Soda), G-1000 (Japan Soda), G-2000 (Japan Soda), G-3000 (Japan Soda), combinations thereof, or other suitable liquid rubber resins.

（ D ) Catalyst

In some embodiments, to enhance system reactivity, the resin composition may further include a catalyst (D). The catalyst (D) is not particularly limited and may be selected as needed. For example, the catalyst (D) may include a peroxide or other suitable catalyst. Specific examples of commercially available peroxide catalysts include 1,3-1,4-Bis(tert-butylperoxyisopropyl)benzen (LUPEROX® F, ARKEMA), Dicumyl peroxide (LUPEROX® DC, ARKEMA), tert-butylcumylperoxide (LUPEROX® 801, ARKEMA), 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (LUPEROX® 101, ARKEMA), combinations thereof, or other suitable peroxide catalysts.

Based on 100 parts by weight of the total resin composition, the amount of catalyst (D) used is 0.1 to 5 phr, preferably 0.1 to 0.5 phr. Exceeding this range may result in residual catalyst (D) in the resin composition, hindering subsequent processing and increasing the electrical properties of the resin composition, failing to meet product requirements.

（ E ) Crosslinking agent

In this embodiment, the crosslinking agent (E) is used to increase the crosslinking degree of the thermosetting resin, adjust the rigidity and toughness of the substrate, and adjust the processability. The crosslinking agent used may be triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethallyl isocyanurate (TMAIC), diallyl phthalate, divinylbenzene, 1,2,4-Triallyl trimellitate, or a combination thereof.

In some embodiments, the amount of the crosslinking agent (E) may be approximately 5 wt % to 45 wt %, preferably approximately 5 wt % to 10 wt %, based on the total weight of the resin composition. If the amount of the crosslinking agent (E) exceeds this range, the resin composition may contain residual crosslinking agent (E), hindering subsequent processing and lowering the glass transition temperature of the resin composition, failing to meet product requirements. If the amount of the crosslinking agent (E) is below this range, the stiffness and toughness of the thermosetting resin may not be effectively improved.

（ F ) Spherical silica

In some embodiments, the resin composition may further include (F) spherical silica. The spherical silica may be prepared using a synthetic method to reduce electrical properties while maintaining fluidity and filling properties. The spherical silica may have an acrylic or vinyl surface modification, a purity of approximately 99.0% or greater, and an average particle size D50 of approximately 2.0 μm to 3.0 μm. In some embodiments, the spherical silica is synthetic silica purchased from Sanjiki Co., Ltd. under the designation EQ2410-SMC.

Based on the total weight of the resin composition, the amount of (F) spherical silica used is 25 wt % to 65 wt %, preferably approximately 40 wt % to 55 wt %. When the amount of (F) spherical silica added exceeds this range, the compatibility between the (F) spherical silica and the resin composition may decrease. When the amount of (F) spherical silica added is less than this range, the dielectric dissipation factor (Df) and dielectric constant (Dk) of the resin composition may not be effectively reduced.

（ G ) Halogen-free flame retardant

Halogen-free flame retardants are used in this embodiment, resulting in environmentally friendly results. Specific examples of halogen-free flame retardants include phosphorus-based flame retardants, such as triphenyl phosphate (TPP), tris(2-chloroethyl) phosphate (TCEP), triphenyl phosphate (TBP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), red phosphorus, phosphorus pentoxide, aminophosphates, ammonium phosphates, ammonium polyphosphate, aluminum diethylphosphinate, or combinations thereof.

Based on the total weight of the resin composition, the halogen-free flame retardant (G) is used in an amount of 5 wt % to 45 wt %, preferably 5 wt % to 15 wt %. When the amount of the halogen-free flame retardant (G) exceeds this range, the glass transition temperature of the resin composition may decrease. When the amount of the halogen-free flame retardant (G) is less than this range, the flame retardant effect may not be effectively improved.

（ H ) Siloxane coupling agent

(H) Siloxane coupling agents can enhance compatibility and crosslinking with glass fiber cloth and powder. Siloxane coupling agents include, but are not limited to, siloxane compounds. Furthermore, depending on the type of functional group, siloxane coupling agents can be further categorized into aminosilane compounds, epoxidesilane compounds, vinylsilane compounds, estersilane compounds, hydroxysilane compounds, isocyanatesilane compounds, methacryloxysilane compounds, and acryloxysilane compounds.

In some embodiments, the (H)siloxane coupling agent may be added in an amount of approximately 0.1 to 5 phr, for example, 0.1 phr, per 100 parts by weight of the resin composition. If the (H)siloxane coupling agent is added in an amount greater than this range, it may overflow from the resin composition, hindering the subsequent lamination process. If the (H)siloxane coupling agent is added in an amount less than this range, it may not effectively enhance compatibility and crosslinking between the glass fiber cloth and the powder.

Other additives

In addition to the above ingredients, the resin composition of the present invention may also contain other additives, such as levelers, antioxidants, etc., but the present invention is not limited to the above examples.

The resin composition of the present invention can be processed into prepregs and metal-clad laminates (CCLs), such as copper clad laminates (CCLs), depending on actual design requirements. Prepregs and CCLs made using the resin composition of the present invention can maintain desired electrical properties while exhibiting excellent peeling resistance, a high glass transition temperature, high flame resistance, and low water absorption. In some preferred embodiments, the dielectric dissipation factor (Df) of the metal-clad laminate (or prepreg) made from the resin composition is less than approximately 0.0035 @ 10 GHz, achieving ultra-low dielectric properties. The resin composition also exhibits a glass transition temperature (Tg) above approximately 200°C, a peel strength above approximately 5 lb/in, and a water absorption rate below 0.2%. < Method for Preparing Metal-clad Laminates >

There are no particular restrictions on the preparation method of the resin composition. For example, the various components of the resin composition are mixed with toluene to form a thermosetting resin varnish. This varnish is then impregnated into a fiber substrate (e.g., LD glass or E glass fiber cloth purchased from Nan Ya Plastics) at room temperature. The varnish is then baked at 170°C for, for example, 3 minutes to produce a prepreg with a resin content of approximately 70 wt % to 80 wt %, for example, approximately 79 wt %.

Finally, the four prepreg layers are stacked between two metal foils (e.g., 35 μm thick copper foils), and the temperature is kept constant for 0 to 30 minutes (e.g., 20 minutes) at a pressure of 10 kg/ ^cm2 to 50 kg/ ^cm2 (e.g., 25 kg/ ^cm2 ) and a temperature of 50°C to 100°C (e.g., 85°C). The temperature is then heated to 180°C to 300°C (e.g., 210°C) at a heating rate of, for example, 3°C/min, and then kept constant for 90 to 180 minutes (e.g., 120 minutes). The prepreg is then slowly cooled to a temperature of 100°C to 150°C (e.g., 130°C) to obtain a metal-clad laminate (e.g., a copper foil substrate) having a thickness of, for example, approximately 0.59 mm. Experimental Example

In order to demonstrate that the resin composition proposed in the present invention can maintain ultra-low dielectric properties while also effectively improving the glass transition temperature and peel strength of the metal-clad laminate, the following experimental examples are specifically conducted. < Examples 1 to 4 and Comparative Example 1>

The modified polyphenylene ether resin (A) used in Examples 1 through 4 has the R structure represented by Chemical Formula 3. Comparative Example 1 omitted the modified polyphenylene ether resin (A) and instead used a conventional polyphenylene ether resin . The remaining components are shown in Table 1. First, the resin compositions of each experimental example were mixed with toluene to form a varnish of the thermosetting resin composition. This varnish was then impregnated into a fiber substrate at room temperature and dried at 170°C for 3 minutes to yield a prepreg with a resin content of approximately 79% by weight. Finally, four prepreg layers were stacked between two 35 μm-thick copper foils. The substrate was held at 85°C for 20 minutes under a ^pressure of 25 kg/cm². The temperature was then increased to 210°C at a rate of 3°C/min, held for 120 minutes, and then slowly cooled to 130°C to obtain a copper foil substrate approximately 0.59 mm thick. Various properties were then evaluated.

[Table 1] Model company Polyphenylene ether resin SA-9000 Sabic (B) Bismaleimide resin BMI-70 KI Chemical (C) Liquid rubber resin B-2000 Japanese Soda (D) Catalyst LUPEROX® F ARKEMA (E) Crosslinking agent TAIC EVONIK (F) Spherical silica EQK0610-SMS Three Ages (G) Halogen-free flame retardant PQ60 Jinyi Chemical (H) Siloxane coupling agent Z6030 DOW CORNING Fiber substrate E glass Nan Ya Plastics LD glass Nan Ya Plastics Evaluation Method ​

Glass transition temperature (°C) was measured using a dynamic mechanical analyzer (DMA).

Water absorption (%): The sample was heated in a pressure cooker at 120°C and 2 atm for 120 minutes, and the weight change before and after heating was calculated.

288°C Solder Heat Resistance (Seconds): Specimens were heated in a pressure cooker at 120°C and 2 atm for 120 minutes. The specimens were then immersed in a 288°C solder pot (EG-353015). The time required for the specimens to delaminate was recorded. Delamination time exceeding 10 minutes was designated "OK," while delamination time less than 10 minutes was designated "NG."

Dielectric constant (Dk): The dielectric constant (Dk) was measured at a frequency of 10 GHz using an HP Agilent E4991A dielectric analyzer.

Dielectric dissipation factor (Df): The dielectric dissipation factor (Df) was measured at a frequency of 10 GHz using an HP Agilent E4991A dielectric analyzer.

Peel strength: Based on the IPC-TM-650 2.4.18.1A test method, a metal substrate peel strength test was conducted using a tensile testing machine to measure the peel strength between the copper foil and the circuit substrate. A higher peel strength indicates that the resin composition has good resistance to peeling from the circuit substrate, i.e., good peel resistance. < Evaluation Results >

[Table 2] Comparative example Example 1 Example 2 Example 3 Example 4 Recipe ratio Polyphenylene ether resin (wt%) 25 0 0 0 0 (A) Modified polyphenylene ether resin (wt%) 0 25 25 twenty two 25 (B) Bismaleimide resin (wt%) 17 17 17 20 17 (C) Liquid rubber resin (wt%) 14 14 14 14 14 (D) Catalyst (phr) 1 1 1 1 0.5 (E) Crosslinking agent (wt%) 5 5 5 5 5 (F) Spherical silica (wt%) 25 25 25 25 25 (G) Halogen-free flame retardant (wt%) 14 14 14 14 14 (H) Siloxane coupling agent (phr) 0.5 0.5 0.5 0.5 0.5 cloth type E glass E glass LD glass LD glass E glass Evaluation results Peel strength (lb/in) 4.10 6.01 5.77 5.40 5.49 Glass transition temperature (℃) 218.5 222.5 220.6 224.8 211.7 Water absorption (PCT 2 hours) (%) 0.197 0.168 0.200 0.208 0.179 Heat resistance (PCT 2 hours) OK OK OK OK OK Dielectric constant (Dk) (measurement frequency 10GHz) 3.58 3.53 3.18 3.26 3.53 Dielectric dissipation factor (Df) (measurement frequency 10 GHz) 0.00313 0.00311 0.00177 0.00182 0.00303 PCT — Pressure Cooker Test

As shown in Table 2, compared to the comparative example, when the resin composition includes (A) modified polyphenylene ether resin; (B) bismaleimide resin; (C) liquid rubber resin; (D) catalyst; (E) crosslinking agent; (F) spherical silica; (G) halogen-free flame retardant; and (H) siloxane coupling agent (Examples 1-4), the resulting copper foil substrates exhibit improved glass transition temperature and peeling resistance, while maintaining good low water absorption, heat resistance, and dielectric properties. Specifically, the peeling resistance of Examples 1-4 is increased to over 5 lb/in.

As can be seen from Example 1 and the comparative example in Table 2 above, Example 1 replaces the polyphenylene ether resin with the modified polyphenylene ether resin (A). While Dk and Df remain comparable, Example 1 exhibits superior peeling force, glass transition temperature, and water absorption compared to the comparative example.

As can be seen from Example 1 and Example 2 in Table 2 above, Example 1 uses an E glass fiber substrate, while Example 2 uses an LD glass fiber substrate. As a result, the dielectric dissipation factor (Df) of Example 2 can reach 0.0017@10GHz.

As can be seen from Examples 2 and 3 in Table 2 above, in Example 3, the amount of (A) modified polyphenylene ether resin was reduced while the amount of (B) bismaleimide resin was increased. Compared to the dielectric dissipation factor (Df) of 0.00177 in Example 2, the dielectric dissipation factor (Df) of Example 3 increased slightly to 0.00182. This indicates that the modified polyphenylene ether resin (A) has a lower dielectric dissipation factor (Df) than the bismaleimide resin (B).

Compared with Example 4, when the peroxide content was reduced to 0.5 phr in Example 1, the glass transition temperature dropped to 211.7°C. This may be due to the decrease in the overall crosslinking degree, which caused the glass transition temperature to drop.

In summary, the examples using modified polyphenylene ether resin (A) exhibited superior performance compared to the comparative examples in terms of peel strength, glass transition temperature, water absorption, and dielectric properties. Example 1 exhibited the best peel strength, while Example 3 exhibited the highest glass transition temperature. Examples 2 and 3 exhibited the best dielectric properties.

In summary, the resin composition of the present invention, through the use of a modified polyphenylene ether resin, can effectively raise the glass transition temperature of the resulting metal-clad laminate to above 200°C, improving its peel resistance to over 5 lb/in. It also achieves a dielectric dissipation factor below 0.0035 and low water absorption. Furthermore, the metal-clad laminate can be used in a wide range of applications, including IC substrates and printed circuit boards.

Although the present invention has been disclosed above by way of embodiments, they are not intended to limit the present invention. Any person having ordinary skill in the art may make slight modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application.

without

Claims (10)

A resin composition comprising: (A) a modified polyphenylene ether resin represented by the following chemical formula 1; (B) a bismaleimide resin; (C) a liquid rubber resin; (D) a catalyst; (E) a crosslinking agent; (F) spherical silica; (G) a halogen-free flame retardant; and (H) a siloxane coupling agent. [Chemical formula 1] In Chemical Formula 1, R is a bisphenol structure and n can represent an integer from 2 to 30, wherein the resin composition includes: 5 wt % to 45 wt % of the (C) liquid rubber resin, based on the total weight of the resin composition. The resin composition of claim 1, wherein R is a chemical structure represented by any one of the following Chemical Formulas 2 to 5: [Chemical Formula 2] [Chemical formula 3] [Chemical formula 4] [Chemical formula 5] In Chemical Formulas 2 to 5, * indicates a position where the unit can be linked to another unit. The resin composition of claim 1, wherein the resin composition comprises, based on the total weight of the resin composition: 10 wt % to 50 wt % of the (A) modified polyphenylene ether resin; 10 wt % to 50 wt % of the (B) bismaleimide resin; 5 wt % to 45 wt % of the (E) crosslinking agent; 25 wt % to 65 wt % of the (F) spherical silica; and 5 wt % to 45 wt % of the (G) halogen-free flame retardant; based on 100 parts by weight of the resin composition, the resin composition further comprises: 0.1 phr to 5 phr of the (D) catalyst; and 0.1 phr to 5 phr of the (H) siloxane coupling agent. The resin composition of claim 1, wherein the crosslinking agent (E) comprises triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethallyl isocyanurate (TMAIC), diallyl phthalate, divinylbenzene, 1,2,4-Triallyl trimellitate, or a combination thereof. The resin composition of claim 1, wherein the (G) halogen-free flame retardant comprises a phosphorus-based flame retardant, wherein the phosphorus-based flame retardant comprises triphenyl phosphate (TPP), tris(2-chloroethyl) phosphate (TCEP), triphenyl phosphate (TBP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), red phosphorus, phosphorus pentoxide, aminophosphates, ammonium phosphates, ammonium polyphosphate, aluminum diethylphosphinate, or a combination thereof. The resin composition according to claim 1, wherein the average particle size (D50) of the (F) spherical silica is 2.0 μm to 3.0 μm. The resin composition of claim 1, wherein the (C) liquid rubber resin has a number average molecular weight (Mn) of 1000 g/mol to 5000 g/mol and contains 10 wt % to 90 wt % of 1,2-vinyl groups. The resin composition of claim 1, wherein the (H) siloxane coupling agent comprises an aminosilane compound, an epoxysilane compound, a vinylsilane compound, an estersilane compound, a hydroxysilane compound, an isocyanatesilane compound, a methacryloxysilane compound, an acryloxysilane compound, or a combination thereof. A prepreg comprising the resin composition according to any one of claims 1 to 8 and a fibrous substrate. A metal clad laminate comprises the prepreg according to claim 9 and a metal foil.