A halogen-free flame-retardant resin composition, a prepreg, a metal-clad laminate, and a printed circuit board

Abstract

This invention provides a halogen-free flame-retardant resin composition, a prepreg containing the same, a metal foil laminate, and a printed circuit board. The halogen-free flame-retardant resin composition comprises the following components in parts by weight: epoxy resin A: 100 parts by weight; low-dielectric curing agent B: 10-75 parts by weight; benzoxazine prepolymer C: 5-40 parts by weight; side-chain epoxy-modified silicone oil D: 0.001-5 parts by weight; and phosphorus-containing flame retardant E: 20-50 parts by weight. In this invention, by introducing the modified benzoxazine prepolymer and the side-chain epoxy-modified silicone oil, the reactivity of the low-polarity epoxy resin composition can be significantly improved, while avoiding the resin shortage problem in the adhesive sheet. Furthermore, since the modified silicone oil contains epoxy-containing side chains, the compatibility between the silicone oil segments and the matrix epoxy can be improved, thereby preventing deterioration of the peel strength and interlayer heat resistance of the board.

Description

Technical Field

[0001] This invention belongs to the field of laminate technology and relates to a halogen-free flame-retardant resin composition, a prepreg containing the composition, a metal foil-coated laminate, and a printed circuit board. Background Technology

[0002] Currently, halogen-free low-dielectric materials primarily utilize epoxy resins and composite curing agents. Besides the contribution of the epoxy resin itself, low-dielectric curing agents are the most common technique for reducing the dielectric constant, with acid anhydride compounds being the preferred choice. However, acid anhydride compounds have relatively high water absorption and CTE, and poor flame retardancy. Therefore, the industry often uses benzoxazine resins as co-curing agents for epoxy resins to improve the performance of the resin composition in terms of water absorption, CTE, and flame retardancy. Although benzoxazine resins have many advantages, they also have the following disadvantages: high curing temperature and slow curing rate, which can easily lead to insufficient resin curing during hot pressing, resulting in insufficient Tg of the board and decreased heat resistance.

[0003] CN116515065A discloses an epoxy resin / prepolymerized benzoxazine copolymer and its preparation method. While the benzoxazine prepolymer can improve the reactivity between benzoxazine and epoxy resin, it can cause resin deficiency in the adhesive sheet.

[0004] CN116376230A discloses a resin adhesive, a prepreg, a metal foil laminate, and a printed circuit board. While modified silicone oil can help improve the resin deficiency problem in low-polarity resin systems, it can also reduce the peel strength and interlayer heat resistance of the board.

[0005] Therefore, in this field, it is desirable to develop a resin composition, as well as a prepreg and laminate material, that can improve the reactivity of epoxy resin and benzoxazine curing systems while improving the appearance of adhesive sheets. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a halogen-free flame retardant resin composition, a prepreg containing the same, a metal foil laminate, and a printed circuit board.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a halogen-free flame-retardant resin composition, the halogen-free flame-retardant resin composition comprising the following components in parts by weight:

[0009] Epoxy resin A: 100 parts by weight;

[0010] Low dielectric curing agent B: 10-75 parts by weight;

[0011] Benzoxazine prepolymer C: 5-40 parts by weight;

[0012] Side-chain epoxy-modified silicone oil D: 0.001-5 parts by weight;

[0013] Phosphorus-containing flame retardant E: 20-50 parts by weight.

[0014] In this invention, by introducing modified benzoxazine prepolymer and silicone oil with epoxy-modified side chains, the reactivity of low-polarity epoxy resin composition can be significantly improved, while avoiding the problem of resin shortage in the adhesive sheet. In addition, since the modified silicone oil contains epoxy-containing side chains, the compatibility between the silicone oil segments and the matrix epoxy can be improved, thereby not deteriorating the peel strength and interlayer heat resistance of the board.

[0015] Preferably, the epoxy resin is selected from any one or a combination of at least two of trifunctional epoxy resins or tetrafunctional epoxy resins.

[0016] In this invention, the epoxy resin is selected from any one or a combination of at least two of the following: dicyclopentadiene type epoxy resin, dimethylphenol type phenolic epoxy resin, tetramethylbiphenyl epoxy resin, biphenyl epoxy resin, phenolic epoxy resin, bisphenol A phenolic epoxy resin, bisphenol F phenolic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, C1-C6 alkyl-containing epoxy resin, MDI-modified epoxy resin, naphthalene-containing epoxy resin, or epoxidized polybutadiene.

[0017] In this invention, the content of the low dielectric curing agent B is 10-75 parts by weight relative to 100 parts by weight of epoxy resin A, for example, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, or 75 parts by weight.

[0018] In this invention, the low dielectric curing agent includes anhydride curing agents and / or reactive ester curing agents.

[0019] Preferably, the anhydride curing agent is selected from any one or a combination of at least two of the following B11 or B12:

[0020]

[0021] Where n:x = 1:1 to 8:1 (e.g., 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1).

[0022] B12 is a copolymer resin having structural units derived from aromatic vinyl compounds and structural units derived from maleic anhydride.

[0023] Preferably, the content of anhydride curing agent in the low dielectric curing agent is 1-50 parts by weight, for example, it can be 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight or 50 parts by weight.

[0024] Preferably, the active ester curing agent is selected from any one or a combination of at least two of active esters having the following B21 or B22 structures:

[0025]

[0026] In B21, X is phenyl or naphthyl, j is 0 or 1, k is 0 or 1, and n indicates that the repeating unit is 0.25 to 1.25 (e.g., 0.25, 0.50, 0.80, 1.0, 1.1, 1.2 or 1.25).

[0027]

[0028] In B21, m, n, and q are independently integers from 1 to 6 (e.g., 1, 2, 3, 4, 5, or 6), X is phenyl or naphthyl, and Y is a group consisting of the following:

[0029] Where K is 0 or 1.

[0030] In this invention, the benzoxazine prepolymer C can be a phenol-hydroxy benzoxazine oligomer generated by the self-polymerization reaction of benzoxazine monomers, and / or a prepolymer formed by further copolymerization of benzoxazine oligomers and epoxy resin.

[0031] Preferably, the number-average molecular weight Mn of the benzoxazine prepolymer is 500-1000, for example: 500, 520, 540, 560, 580, 600, 620, 640, 680, 700, 720, 740, 780, 800, 820, 840, 860, 880, 900, 920, 940, 960, 980, 1000, etc. If the number-average molecular weight Mn of the benzoxazine prepolymer is too low, the reactivity will be poor and the GT will be too long, which is not conducive to the control of the glue GT; if the number-average molecular weight is too high, the reactivity will be too high and the GT will be too short, which is also not conducive to the control of the glue GT.

[0032] The gelation time (GT) is 50-300 s, for example: 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 s, etc. (Test conditions: 0.6±0.1 g, 210±1℃, according to IPC-TM-6502.3.18 standard method). A GT that is too low for the benzoxazine prepolymer will result in a too short GT for the adhesive, leading to excessive reactivity and failing to meet the normal GT control range requirements; conversely, a GT that is too long for the benzoxazine will result in a too long GT for the adhesive, similarly failing to meet the normal GT control range requirements.

[0033] In this invention, the content of the benzoxazine prepolymer C is 5-40 parts by weight relative to 100 parts by weight of epoxy resin A, for example, 5 parts by weight, 8 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight or 40 parts by weight.

[0034] Preferably, the side-chain epoxy-modified silicone oil D has the following structure:

[0035]

[0036] Where m and n are each an integer greater than 1, such as 1, 2, 3, 4, 5, 6, 8, 10, 11, 16, 19, 20, 30, 50, etc., preferably an integer between 8 and 18;

[0037] R1 is independently selected from functional groups in the following structures:

[0038]

[0039] R2 is a C1-C5 alkyl group, or a C1-C5 alkyl group containing an ether bond, or a C1-C5 aryl group containing a phenyl group, for example: -CH2-, -CH2-CH2-, -CH2-CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-CH2-, -CH2-O-, -CH2-CH2-O-, -CH2-CH2-CH2-O-, -CH2-CH2-CH2-CH2-CH2-O-, -CH2-Ph-, -CH2-CH2-Ph-, -CH2-CH2-CH2-CH2-Ph-, -CH2-CH2-CH2-CH2-CH2-Ph-, -CH2-CH2-CH2-CH2-CH2-Ph-, etc., where -Ph- represents phenyl.

[0040] Preferably, the side-chain epoxy-modified silicone oil D can be selected from organic modified silicone oils produced by Shin-Etsu Chemical Co., Ltd. of Japan: X-22-343, KF-101, KF-1001, X-22-2000, X-22-2046, KF-102, X-22-4741, KF-1002, KF-1005, etc.

[0041] Preferably, the epoxy equivalent of the side-chain epoxy-modified silicone oil D is ≤4000 g / mol, for example: 4000, 3800, 3600, 3500, 3400, 3300, 3200, 3100, 3000, 2900, 2800, 2700, 2500, 2000, 1500, 1000, 800, 600, 400, 300, 200, etc. Too high an epoxy equivalent will lead to poor compatibility between the silicone oil and the cured epoxy resin, cracking of the interlayer bonding of the board, and decreased heat resistance.

[0042] In this invention, relative to 100 parts by weight of epoxy resin A, the content of the side-chain epoxy-modified silicone oil D is 0.001 parts by weight, 0.005 parts by weight, 0.01 parts by weight, 0.05 parts by weight, 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, or 5 parts by weight. Insufficient use of the side-chain epoxy-modified silicone oil will result in insufficient resin in the bonding sheet, which is detrimental to the appearance quality requirements of HDI fine circuits; excessive use will lead to a decrease in the Tg of the board, cracking of interlayer adhesion, and insufficient heat resistance of T288.

[0043] Preferably, the phosphorus-containing flame retardant is selected from inorganic phosphorus-based flame retardants and / or organic phosphorus-based flame retardants.

[0044] Preferably, the inorganic phosphorus-based flame retardant is selected from any one or a combination of at least two of red phosphorus, ammonium phosphate, phosphoric acid, or phosphine oxide.

[0045] Preferably, the ammonium phosphate includes any one or a combination of at least two of monoammonium phosphate, diammonium phosphate, or triammonium phosphate.

[0046] Preferably, the organic phosphorus-based flame retardant is selected from any one or a combination of at least two of aromatic phosphates, monosubstituted phosphonate diesters, disubstituted hypophosphite esters, metal salts of disubstituted hypophosphite, cyclic organophosphorus compounds, or phosphorus-containing phenolic resins. More preferably, it is a combination of any one or at least two of aromatic phosphates, metal salts of disubstituted hypophosphite, or phosphorus-containing phenolic resins; and even more preferably, it is a phosphorus-containing phenolic resin.

[0047] In the halogen-free flame retardant resin composition of the present invention, the amount of the phosphorus-containing flame retardant relative to 100 parts by weight of epoxy resin A can be 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, or 50 parts by weight.

[0048] Preferably, the halogen-free flame retardant resin composition further includes filler F.

[0049] Preferably, the filler is selected from any one or a combination of at least two of the following: aluminum hydroxide, silicon dioxide, talc, boehmite, zeolite, wollastonite, magnesium oxide, calcium silicate, calcium carbonate, clay, or mica.

[0050] Preferably, the median particle size D50 of the filler is 1.8-3.2 μm (e.g., 1.8 μm, 2.0 μm, 2.3 μm, 2.5 μm, 2.8 μm, 3.0 μm or 3.2 μm), and the maximum particle size D100 is 5.0-15.0 μm (e.g., 5.0 μm, 7.0 μm, 10.0 μm, 12.0 μm, 14.0 μm or 15.0 μm).

[0051] Preferably, the physical form of the filler can be sheet-like, rod-like, spherical, hollow spherical, granular, fibrous, or plate-like.

[0052] In this invention, the filler may be selectively treated with a silane coupling agent.

[0053] Preferably, in the halogen-free flame retardant resin composition, the filler content is 40-400 parts by weight relative to 100 parts by weight of epoxy resin A, for example, it can be 40 parts by weight, 50 parts by weight, 80 parts by weight, 100 parts by weight, 130 parts by weight, 150 parts by weight, 180 parts by weight, 200 parts by weight, 250 parts by weight, 300 parts by weight, 350 parts by weight, or 400 parts by weight.

[0054] Preferably, the halogen-free flame retardant resin composition further includes a curing accelerator G.

[0055] Preferably, the curing accelerator is selected from any one or a combination of at least two of imidazole accelerators, pyridine curing agents, Lewis acid curing agents, amine curing agents, phenolic curing agents, cyanate ester compounds, or reactive ester compounds.

[0056] On the other hand, the present invention provides a prepreg comprising the halogen-free flame-retardant resin composition as described above.

[0057] Preferably, the prepreg comprises a base material and a halogen-free flame-retardant resin composition as described above adhered to the base material;

[0058] Preferably, the prepreg comprises a base material and a halogen-free flame-retardant resin composition as described above, which is attached to the base material after impregnation and drying.

[0059] On the other hand, the present invention provides a metal foil laminate, the metal foil laminate comprising at least one prepreg as described above and a metal foil covering one or both sides of the laminated prepreg.

[0060] On the other hand, the present invention provides a printed circuit board comprising at least one of the prepreg as described above or the metal foil laminate as described above.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The halogen-free flame-retardant resin composition of the present invention, by introducing modified benzoxazine prepolymer and silicone oil with epoxy-modified side chains, can significantly improve the reactivity of the low-polarity epoxy resin composition and avoid the problem of resin shortage in the adhesive sheet. In addition, since the modified silicone oil contains epoxy-containing side chains, it can improve the compatibility between the silicone oil segments and the matrix epoxy, thereby not deteriorating the peel strength and interlayer heat resistance of the board. Detailed Implementation

[0063] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0064] The materials and grade information involved in the following embodiments and comparative examples are as follows:

[0065] A1: CNE type epoxy resin (o-cresol epoxy resin): NPCN-704, epoxy equivalent: 200-220g / eq, Nan Ya Resin;

[0066] A2: HP-7200HHH, DCPD type epoxy resin, epoxy equivalent: 280-290g / eq, Japanese DIC;

[0067] A3: Phenolic epoxy resin, BNE-200, equivalent weight: 200g / eq, Chang Chun Resin, Taiwan, China;

[0068] B1: Styrene-maleic anhydride copolymer: SMA-EF40, CrayValley, USA;

[0069] B2: Active ester curing agent: DFE-617L, Sichuan Dongcai;

[0070] C1: Benzoxazine prepolymer (self-made), Mn: 500, GT: 300s;

[0071] C2: Benzoxazine prepolymer (self-made), Mn: 700, GT: 200s;

[0072] C3: Benzoxazine prepolymer (self-made), Mn: 900, GT: 100s;

[0073] C4: Benzoxazine prepolymer (self-made), Mn: 1000, GT: 50s;

[0074] C5: Epoxy benzoxazine prepolymer (self-made), Mn: 1000, GT: 150s;

[0075] C6: Benzoxazine prepolymer (self-made), Mn: 1200, GT: 30s;

[0076] C7: Benzoxazine resin monomer (PF3500, Chang Chun, Taiwan, China), Mn: 450, GT: 400s;

[0077] D1: Epoxy-modified silicone oil: brand name KF-101, Shin-Etsu Chemical, Japan, with a side-chain epoxy structure and an epoxy equivalent of 350 g / mol.

[0078] D2: Epoxy-modified silicone oil: Grade X-22-4741, Shin-Etsu Chemical, Japan, side-chain epoxy polyether type, epoxy equivalent is 2500 g / mol;

[0079] D3: Epoxy-modified silicone oil: brand name KF-102, Shin-Etsu Chemical, Japan, alicyclic epoxy with side chain and epoxy equivalent of 3600 g / mol.

[0080] D4: Epoxy-modified silicone oil: brand KF-1002, Shin-Etsu Chemical, Japan, side-chain epoxy polyether type, epoxy equivalent is 4300g / mol.

[0081] D5: Epoxy-modified silicone oil: brand name KF-22-163, Shin-Etsu Chemical, Japan, terminal epoxy type, epoxy equivalent is 200g / mol.

[0082] D6: Epoxy-modified silicone oil: brand KF-864, Shin-Etsu Chemical, Japan, side chain amino type, amino equivalent of 3800 g / mol.

[0083] E1: Phosphate ester flame retardant: brand name PX200, Daihachi Chemical, Japan.

[0084] E2: Phosphorus-containing phenolic resin: Grade XZ92741, DOW Company, USA.

[0085] F: Spherical silica: Q099, D100 is 5μm, Chongqing Jinyi;

[0086] G: Curing accelerator: 2-ethyl-4-methylimidazole, Shikoku Kasei.

[0087] Preparation Example 1: Synthesis of benzoxazine prepolymer C1

[0088] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 40 g of benzoxazine resin monomer (PF3500, Chang Chun, Taiwan), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 2 hours. Heating was then stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous benzoxazine prepolymer C1. The average number-average molecular weight (Mn) of benzoxazine prepolymer C1 was 500, and the GT was 300s.

[0089] Preparation Example 2: Synthesis of benzoxazine prepolymer C2

[0090] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 40 g of benzoxazine resin monomer (PF3500, Chang Chun, Taiwan), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 3 h. Heating was then stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous benzoxazine prepolymer C2. The average number-average molecular weight (Mn) of benzoxazine prepolymer C2 was 700, and the GT was 200s.

[0091] Preparation Example 3: Synthesis of benzoxazine prepolymer C3

[0092] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 40 g of benzoxazine resin monomer (PF3500, Chang Chun, Taiwan), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 4 h. Heating was then stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous benzoxazine prepolymer C3. The average number-average molecular weight (Mn) of benzoxazine prepolymer C3 was 900, and the GT was 100s.

[0093] Preparation Example 4: Synthesis of benzoxazine prepolymer C4

[0094] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 40 g of benzoxazine resin monomer (PF3500, Chang Chun, Taiwan), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 5 h. Heating was then stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous benzoxazine prepolymer C4. The average number-average molecular weight (Mn) of benzoxazine prepolymer C4 was 1000, and the GT was 50s.

[0095] Preparation Example 5: Synthesis of Epoxy-Modified Benzoxazine Prepolymer C5

[0096] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 50 g of benzoxazine prepolymer C1 (the product of Synthesis Example 1), 20 g of bisphenol A epoxy resin (GELR-128E, Guangzhou Hongchang Electronics), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 1 h, after which heating was stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous epoxy-modified benzoxazine prepolymer C5. The average number-average molecular weight (Mn) of epoxy-modified benzoxazine prepolymer C5 was 1000, and the GT was 150s.

[0097] Preparation Example 6: Synthesis of benzoxazine prepolymer C6

[0098] In a 500 mL three-necked flask equipped with a stirrer, condenser, and thermometer, 40 g of benzoxazine resin monomer (PF3500, Chang Chun, Taiwan), 0.1 g of accelerator (2E4MZ), and 150 g of a mixed solution of butanone and xylene (butanone to xylene volume ratio 1:2) were added. After stirring until homogeneous, the mixture was heated to 130 °C and refluxed for 6 h. Heating was then stopped. The resin layer was collected, and the solvent was removed using a rotary evaporator to obtain a yellowish-brown viscous benzoxazine prepolymer C6. The average number-average molecular weight (Mn) of benzoxazine prepolymer C6 was 1200, and the GT was 30s.

[0099] The formulation composition and physical property data of each embodiment are shown in Tables 1 and 2, and the formulation composition and physical property data of the comparative examples are shown in Tables 3 and 4.

[0100] Table 1

[0101]

[0102]

[0103] Table 2

[0104]

[0105]

[0106] Table 3

[0107]

[0108]

[0109] Table 4

[0110]

[0111] Note: In Tables 1 and 2, "NG" indicates that the T288 test failed, and "OK" indicates that the T288 test passed.

[0112] The performance testing methods described above are as follows:

[0113] (1) Adhesive GT: The test method of IPC-TM-650 standard, method 2.3.18 was used for determination.

[0114] (2) Glass transition temperature: Differential scanning calorimetry (DSC) was used to determine the temperature according to the DSC method specified in 2.4.25 of IPC-TM-650.

[0115] (3) Dielectric constant (1 GHz): The dielectric constant was determined according to the method specified in section 2.5.5.9 of IPC-TM-650 using the parallel plate capacitance method.

[0116] (4) T288: The determination shall be performed using a thermomechanical analyzer in accordance with the method specified in IPC-TM-650 2.4.24.1.

[0117] (5) Flammability: Determined according to the vertical burning method of UL-94 standard.

[0118] (6) Interlayer adhesion: Performed according to IPC-TM-650 standard, vertical method.

[0119] Regarding the ground truth (GT) performance of the adhesives: Compared to Example 1, Comparative Example 1, due to the lower amount of benzoxazine prepolymer, resulted in a longer GT and slower reactivity, leading to insufficient curing during subsequent lamination. Compared to Example 1, Comparative Example 2, due to the higher amount of benzoxazine prepolymer, resulted in a shorter GT, failing to meet the normal GT control range requirements. Compared to Example 1, Comparative Example 3 used a benzoxazine prepolymer with a too-large molecular weight, resulting in a shorter GT and failing to meet the normal GT control range requirements. Compared to Example 1, Comparative Example 4 used unprepolymerized benzoxazine, resulting in a too-long GT and failing to meet the normal GT control range requirements.

[0120] From the appearance of the bonding sheet: compared with Example 1, the amount of epoxy modified silicone oil used in Comparative Example 5 was too small, resulting in a lack of resin in the bonding sheet, which is not conducive to the appearance quality requirements of HDI fine circuits for the bonding sheet.

[0121] From the perspective of the board performance: Compared with Example 1, Comparative Example 6 used too much epoxy-modified silicone oil, resulting in a decrease in the board's Tg, cracking of interlayer adhesion, and insufficient T288 heat resistance. Compared with Example 1, Comparative Example 7 used epoxy-modified silicone oil with too high an epoxy equivalent, resulting in poor compatibility between the silicone oil and the epoxy resin cured product, cracking of the interlayer adhesion, and decreased heat resistance. Compared with Example 1, Comparative Example 8 used end-group epoxy-modified silicone oil, which had insufficient crosslinking points with the epoxy resin system, resulting in cracking of the interlayer adhesion and decreased heat resistance. Compared with Example 1, Comparative Example 9 used side-chain amino-type modified silicone oil, resulting in insufficient resin in its bonding sheet, which is not conducive to the appearance quality requirements of the bonding sheet for HDI fine circuits. Compared with Example 1, Comparative Example 10 used a lower amount of phosphorus-containing flame retardant, resulting in poor flame retardant performance of the board, only reaching V-1 rating. Compared with Example 1, Comparative Example 11 used a higher amount of phosphorus-containing flame retardant, which resulted in a decrease in the Tg of the board and a deterioration in the heat resistance of T288.

[0122] The applicant declares that this invention is illustrated through the above embodiments to demonstrate the halogen-free flame-retardant resin composition, the prepreg containing it, the metal foil laminate, and the printed circuit board of the present invention. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the products of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A halogen-free flame-retardant resin composition, characterized in that, The halogen-free flame-retardant resin composition comprises the following components in parts by weight: Epoxy resin A: 100 parts by weight; Low dielectric curing agent B: 10-75 parts by weight; Benzoxazine prepolymer C: 5-40 parts by weight; Side-chain epoxy-modified silicone oil D: 0.001-5 parts by weight; Phosphorus-containing flame retardant E: 20-50 parts by weight; The benzoxazine prepolymer C is a phenol-hydroxyl-containing benzoxazine oligomer generated by the self-polymerization reaction of benzoxazine monomers, and / or a prepolymer formed by further copolymerization of benzoxazine oligomers with epoxy resin; The number-average molecular weight Mn of the benzoxazine prepolymer C is 500-1000; The side-chain epoxy-modified silicone oil D has the following structure: Where m and n are each an integer greater than 1; R1 is independently selected from functional groups in the following structures: or R2 is a C1-C5 alkyl group, or a C1-C5 alkyl group containing an ether bond, or a C7-C11 alkyl group containing a phenyl group; The epoxy equivalent of the side-chain epoxy-modified silicone oil D is ≤4000g / mol.

2. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The epoxy resin A is selected from any one or a combination of at least two of trifunctional or tetrafunctional epoxy resins.

3. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The epoxy resin A is selected from any one or a combination of at least two of the following: dicyclopentadiene type epoxy resin, dimethylphenol type phenolic epoxy resin, tetramethylbiphenyl epoxy resin, bisphenol A phenolic epoxy resin, bisphenol F phenolic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, C1-C6 alkyl-containing epoxy resin, MDI modified epoxy resin, naphthalene-containing epoxy resin, or epoxidized polybutadiene.

4. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The low dielectric curing agent B includes anhydride curing agents and / or reactive ester curing agents.

5. The halogen-free flame-retardant resin composition according to claim 4, characterized in that, The anhydride curing agent is selected from any one or a combination of at least two of the following B11 or B12: B11 B12 Where n:x = 1:1 ~ 8:

1.

6. The halogen-free flame-retardant resin composition according to claim 4, characterized in that, The content of anhydride curing agent in the low dielectric curing agent B is 1-50 parts by weight.

7. The halogen-free flame-retardant resin composition according to claim 4, characterized in that, The active ester curing agent is selected from any one or a combination of at least two of active esters having the following B21 or B22 structures: B21 In B21, X is either phenyl or naphthyl, j is 0 or 1, k is 0 or 1, and n indicates that the repeating unit is 0.25 to 1.

25. B22 In B22, m, n, and q are independent integers from 1 to 6, X is phenyl or naphthyl, and Y is a group such as: Where K is 0 or 1.

8. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The gelation time of the benzoxazine prepolymer C is 50-300 s.

9. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The phosphorus-containing flame retardant E is selected from inorganic phosphorus-based flame retardants and / or organic phosphorus-based flame retardants.

10. The halogen-free flame-retardant resin composition according to claim 9, characterized in that, The inorganic phosphorus-based flame retardant is selected from any one or a combination of at least two of red phosphorus, ammonium phosphate, phosphoric acid, or phosphine oxide.

11. The halogen-free flame-retardant resin composition according to claim 10, characterized in that, The ammonium phosphate includes any one or a combination of at least two of monoammonium phosphate, diammonium phosphate, or triammonium phosphate.

12. The halogen-free flame-retardant resin composition according to claim 9, characterized in that, The organic phosphorus-based flame retardant is selected from any one or a combination of at least two of the following: aromatic phosphate esters, monosubstituted phosphonate diesters, disubstituted hypophosphonates, metal salts of disubstituted hypophosphonic acids, cyclic organophosphorus compounds, or phosphorus-containing phenolic resins.

13. The halogen-free flame-retardant resin composition according to claim 12, characterized in that, The organic phosphorus-based flame retardant is selected from any one or a combination of at least two of aromatic phosphates, metal salts of disubstituted phosphonates, or phosphorus-containing phenolic resins.

14. The halogen-free flame-retardant resin composition according to claim 13, characterized in that, The organic phosphorus-based flame retardant is selected from phosphorus-containing phenolic resins.

15. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The halogen-free flame retardant resin composition also includes filler F.

16. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The filler F is selected from any one or a combination of at least two of the following: aluminum hydroxide, silicon dioxide, talc, boehmite, zeolite, wollastonite, magnesium oxide, calcium silicate, calcium carbonate, clay, or mica.

17. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The median particle size D50 of the filler F is 1.8-3.2 μm, and the maximum particle size D100 is 5.0-15.0 μm.

18. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The physical form of the filler F is flake-shaped, rod-shaped, granular, or fibrous.

19. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The physical form of the filler F is spherical or plate-shaped.

20. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The physical form of the filler F is a hollow sphere.

21. The halogen-free flame-retardant resin composition according to claim 15, characterized in that, The content of filler F in the halogen-free flame retardant resin composition is 40-400 parts by weight relative to 100 parts by weight of epoxy resin A.

22. The halogen-free flame-retardant resin composition according to claim 1, characterized in that, The halogen-free flame-retardant resin composition also includes a curing accelerator G.

23. The halogen-free flame-retardant resin composition according to claim 22, characterized in that, The curing accelerator G is selected from any one or a combination of at least two of imidazole accelerators, pyridine accelerators, or Lewis acid accelerators.

24. A prepreg, characterized in that, The prepreg comprises the halogen-free flame-retardant resin composition as described in any one of claims 1-23.

25. A metal foil-coated laminate, characterized in that, The metal foil laminate includes at least one prepreg as described in claim 24 and a metal foil covering one or both sides of the laminated prepreg.

26. A printed circuit board, characterized in that, The printed circuit board includes at least one of the prepreg as described in claim 24 or the metal foil laminate as described in claim 25.

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