A resin composition, a circuit material including the same, and a printed circuit board

Abstract

The present application provides a kind of resin composition, the circuit material and printed circuit board comprising it, the resin composition includes (A) first thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, number average molecular weight Mn≤5000g / mol;(B) second thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, number average molecular weight Mn≥15000g / mol;(C) first filler, including rutile titanium dioxide, D50 is 3~6 μm, purity ≥99.5%;(D) second filler, including amorphous fused silica, D50 is 8~12 μm, purity ≥99.5%;(E) flame retardant;(F) silane coupling agent;(G) free radical initiator.The circuit material prepared by the resin composition has high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant and good thickness consistency.

Description

Technical Field

[0001] This invention belongs to the field of electronic materials technology, specifically relating to a resin composition, a dielectric substrate containing the resin, circuit materials, and a printed circuit board. Background Technology

[0002] In recent years, portable devices such as smartphones have become increasingly widespread. Furthermore, technological innovations such as IoT (Internet of Things) are also advancing, resulting in a continuous increase in home appliances and electronic devices with wireless communication capabilities. This has led to a surge in the amount of information transmitted via wireless networks. To ensure communication speed and quality, the development of the 5G mobile communication system is underway, and it is gradually being implemented. 5G utilizes multiple antenna elements for advanced beamforming and spatial reuse. In addition to the previously used 6GHz frequency band, it also uses millimeter-wave band signals at higher frequencies, such as tens of GHz, thus promising significantly higher communication speeds and improved communication quality. In 5G, antenna modules need to be able to handle high-frequency signals, which specifically requires the dielectric substrate to have a low dielectric loss tangent (Df) at high frequencies.

[0003] Because high-frequency radio waves exhibit high linearity, signals carrying these waves are easily blocked by obstacles such as buildings. Therefore, to avoid this blockage, multiple antenna devices are mounted in the antenna module. Since increasing the relative permittivity (Dk) of the substrate material enables the miniaturization of the antenna device, increasing the relative permittivity (Dk) is effective for multiple antenna devices and also leads to the miniaturization of the antenna module, and consequently, the miniaturization of the communication device. Therefore, the dielectric substrate used in antenna modules capable of handling high-frequency signals must have a relatively high permittivity (Dk) of a specified value and a low dielectric loss tangent (Df).

[0004] Microstrip antennas are a type of antenna developed in the early 1970s. Due to their advantages such as simple structure, low profile, light weight, conformal mounting to aircraft surfaces, and integration with microstrip circuits, they have been widely used in communications, radar, and other fields. However, because microstrip antennas are resonant structures, their structural dimensions are usually large when applied to lower frequencies, failing to meet certain small-size requirements. Furthermore, the continuous development of wireless communication systems in recent years has placed higher demands on personal communication terminal modules. For example, with the increasingly significant role of GPS and BeiDou systems in daily life, RF front-end modules are becoming increasingly portable: light, thin, short, and small. Therefore, solving the miniaturization problem of microstrip antennas has become one of the main research topics for microstrip antennas.

[0005] Currently, the main methods for miniaturizing microstrip antennas include using special dielectric substrates, loading short-circuit probes, surface slotting, adding active networks, and employing special microstrip patch designs. A common method is to use high-dielectric-constant dielectric substrates to reduce the size of the microstrip antenna. However, the main drawback of these high-dielectric-constant dielectric antennas is that they generate strong surface waves, resulting in significant surface losses, which reduces gain and efficiency. To improve gain, a high-dielectric-constant dielectric is often applied to the antenna surface, but this increases the antenna's thickness.

[0006] Based on the fundamental theory and design of microstrip antennas, selecting a dielectric substrate with a high dielectric constant (Dk) can reduce the antenna size. Covering the antenna surface with a high dielectric constant medium to increase the thickness can increase the radiation efficiency and improve the antenna gain.

[0007] In antenna design, the dielectric constant and thickness stability and consistency of the substrate material are crucial indicators affecting antenna gain and other performance characteristics. Variations in substrate thickness can reduce antenna efficiency. In antenna design, the thickness variation of the dielectric layer has a greater impact on antenna performance than the dielectric constant stability. Furthermore, thickness variations also lead to variations in resin content, which directly affects the dielectric constant stability.

[0008] When manufacturing thick dielectric substrates, in order to ensure thickness uniformity, a large amount of filler and high molecular weight resin are used to increase the dielectric constant (Dk) and reduce adhesive flow. This can lead to low copper foil peel strength of the dielectric substrate, and even voids may be generated inside the dielectric substrate, which further leads to poor stability of the dielectric constant of the dielectric substrate.

[0009] In summary, to handle the high frequencies of antenna modules, a low dielectric loss tangent (Df) is required for the dielectric substrate. For miniaturization of antenna modules, and consequently, communication devices, a relatively high dielectric constant (Dk) is required for the dielectric substrate. Using a dielectric substrate with a high dielectric constant (Dk) can reduce antenna size; to improve gain, the antenna thickness must be increased, thus increasing the thickness of the dielectric substrate. However, increasing the thickness of the dielectric substrate presents many challenges in maintaining the stability and uniformity of the dielectric constant and thickness. To ensure thickness uniformity, large amounts of fillers and high molecular weight resins are used to increase the dielectric constant (Dk) and reduce resin flow, which leads to lower copper foil peel strength of the dielectric substrate.

[0010] Therefore, how to provide a high-performance resin composition that can be used to prepare circuit materials with high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant and good thickness uniformity has become an urgent technical problem to be solved. Summary of the Invention

[0011] To address the shortcomings of existing technologies, the present invention aims to provide a resin composition, a circuit material comprising the resin composition, and a printed circuit board. In this invention, by designing the specific composition of the resin composition, a high-performance resin composition is prepared. The resulting circuit material exhibits a high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant, and good thickness uniformity.

[0012] To achieve this objective, the present invention adopts the following technical solution:

[0013] On one hand, the present invention provides a resin composition comprising the following components:

[0014] (A) A first thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, having a number-average molecular weight Mn ≤ 5000 g / mol;

[0015] (B) A second thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, having a number average molecular weight Mn ≥ 15000 g / mol;

[0016] (C) The first filler consists of rutile titanium dioxide with a particle size D50 of 3–6 μm and a purity of ≥99.5%.

[0017] (D) Second filler, comprising amorphous fused silica with a particle size D50 of 8–12 μm and a purity ≥99.5%;

[0018] (E) Flame retardants;

[0019] (F) Silane coupling agent;

[0020] (G) Free radical initiator.

[0021] In this invention, the first thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin, has a number-average molecular weight (Mn) ≤ 5000 g / mol. The lower molecular weight of the first thermosetting resin primarily serves to facilitate the flow of adhesive and the wetting of fiberglass cloth in the formulation, thereby improving the density of the sheet and the peel strength of the copper foil. In this invention, the number-average molecular weight of the first thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin, can be 1000 g / mol, 1400 g / mol, 1800 g / mol, 2200 g / mol, 2600 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, or 5000 g / mol, etc.

[0022] In this invention, the second thermosetting resin is polybutadiene resin and / or polybutadiene copolymer resin, with a number average molecular weight Mn ≥ 15000 g / mol. The high molecular weight of the second thermosetting resin is mainly used to adjust the flow rate in the formulation. When the flow rate of the formulation is large, the proportion of the second thermosetting resin needs to be increased to reduce the flow rate. When the flow rate of the formulation is small, the proportion of the second thermosetting resin needs to be reduced to increase the flow rate. In this invention, the number average molecular weight of the second thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin, can be 15000 g / mol, 16000 g / mol, 17000 g / mol, 18000 g / mol, 19000 g / mol, 20000 g / mol, 22000 g / mol, 24000 g / mol, 25000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 65000 g / mol, 70000 g / mol, 80000 g / mol, 90000 g / mol, 100000 g / mol, 110000 g / mol, or 120000 g / mol, etc.

[0023] In this invention, the first filler is rutile titanium dioxide with a particle size D50 of 3–6 μm and a purity ≥99.5%. Rutile titanium dioxide has a high dielectric constant, thus exhibiting excellent electrical properties. Different crystal forms of titanium dioxide show significant differences in certain physical properties; for example, rutile titanium dioxide has a dielectric constant of 114, while anatase titanium dioxide has a relatively low dielectric constant of only 48. Therefore, to improve the dielectric constant of the dielectric substrate, this invention selects rutile titanium dioxide.

[0024] When using different resin formulations, the surface of rutile titanium dioxide is treated with a silane coupling agent to improve the compatibility between rutile titanium dioxide and the resin. For example, a vinyl-containing silane coupling agent consistent with the main resin of this invention is selected for surface treatment.

[0025] Rutile titanium dioxide has different particle sizes. Through extensive experimental research, the inventors of this invention discovered that when using the resin formulation of this invention, if the particle size D50 of the rutile titanium dioxide is less than 3 μm, it easily leads to filler agglomeration. Furthermore, the filler has a high oil absorption value, and the viscosity of the adhesive is too high, affecting the processability of the adhesive. If the particle size D50 of the rutile titanium dioxide is greater than 6 μm, it will also cause problems due to the density of the rutile titanium dioxide (4.26 g / cm³). 3Larger rutile titanium dioxide particles tend to settle easily, resulting in uneven dispersion with other fillers in the formulation. This ultimately leads to unstable dielectric constant and poor consistency of the dielectric substrate. Therefore, this invention limits the particle size D50 of rutile titanium dioxide to 3–6 μm. In this invention, the median particle size D50 of the rutile titanium dioxide filler can be 3 μm, 4 μm, 4.5 μm, 5 μm, or 6 μm, etc.

[0026] In this invention, the inventors discovered through extensive experimental research that the purity of rutile titanium dioxide affects the dielectric loss of the dielectric substrate. This effect is particularly pronounced when the proportion of rutile titanium dioxide in the formulation is high. When the purity is ≥99.5%, the dielectric loss Df ≤0.0030 at a frequency of 10 GHz is achieved using the SPDR method for the dielectric substrate layer. Higher purity rutile titanium dioxide results in fewer soluble conductive substances or impurities in the filler, leading to lower dielectric loss in the dielectric substrate. To further control the dielectric loss of the dielectric substrate, the conductivity of the rutile titanium dioxide is further optimized to be ≤10 μS / cm, for example, 10 μS / cm, 9 μS / cm, 8 μS / cm, 7 μS / cm, 6 μS / cm, 5 μS / cm, 4 μS / cm, 3 μS / cm, 2 μS / cm, 1 μS / cm, etc.

[0027] In this invention, the second filler is amorphous fused silica with a particle size D50 of 8–12 μm and a purity ≥99.5%. To achieve a more compact packing of fillers with different particle sizes, this invention uses a combination of large-particle-size silica and small-particle-size titanium dioxide to produce a better compact packing effect. Through extensive experimental research, the inventors discovered that when using the resin formulation of this invention, if the particle size D50 of the amorphous fused silica is less than 8 μm, its combination with small-particle-size titanium dioxide increases the viscosity of the adhesive, affecting the application process. Furthermore, the filler has a high oil absorption value, making the substrate prone to voids, leading to poor dielectric constant stability of the substrate and reduced copper foil peel strength. If the particle size D50 of the amorphous fused silica is greater than 12 μm, the adhesive flow during lamination will be excessive, especially when laminating thicker plates, easily creating grooves and resulting in poor thickness uniformity of the substrate. In this invention, the median particle size D50 of the amorphous fused silica filler can be 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm, etc. In this invention, the purity of the amorphous fused silica used is ≥99.5% to obtain low dielectric loss. To further ensure low dielectric loss of the dielectric substrate, a conductivity ≤10 μS / cm is preferred, for example, it can be 10 μS / cm, 9 μS / cm, 8 μS / cm, 7 μS / cm, 6 μS / cm, 5 μS / cm, 4 μS / cm, 3 μS / cm, 2 μS / cm, 1 μS / cm, etc.

[0028] In this invention, based on 100 parts by weight of the resin composition, the sum of the weight parts of components (A) and (B) is 18 to 24 parts by weight (e.g., 18, 19, 20, 22, or 24 parts, etc.), the amount of component (C) is 14 to 45 parts by weight (e.g., 14, 18, 24, 28, 35, 40, 42, or 45 parts, etc.), and the amount of component (D) is 25 to 55 parts by weight (e.g., 2...). Components (A and B) can be used in proportions of 5, 28, 32, 40, 48, 50, 52, or 55 parts. If the resin ratio is too low, it will not fill the gaps between the fillers, easily forming voids. This leads to voids in the board and low peel strength. Voids also result in poor thickness uniformity and overall dielectric constant uniformity. If the resin ratio is too high, it will cause excessive resin flow, affecting the thickness uniformity and overall dielectric constant uniformity of the board. Component (C) rutile titanium dioxide has a relatively high dielectric constant, with an average dielectric constant of 114, while component (D) amorphous fused silica has a lower dielectric constant, ranging from 3.6 to 3.8. Different dielectric constants can be obtained by adjusting the ratio between components (C) and (D).

[0029] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0030] As a preferred embodiment of the present invention, the mass ratio of component (A) to component (B) is 1:(0.5-2), for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8 or 1:2, etc.

[0031] Because component (A), the first thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn ≤ 5000 g / mol), has a small molecular weight, it will flow under heat and pressure when used alone, easily causing surface defects such as grooves. Furthermore, the thickness at the edges of the board is relatively thin, resulting in unstable overall board thickness and poor dielectric constant consistency. To ensure better thickness consistency and overall dielectric constant consistency of the high-frequency substrate, component (B), the second thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn ≥ 15000 g / mol), is added to the formulation in this invention. The best effect is achieved when the mass ratio of component (A) to component (B) is 1:(0.5~2). If the proportion of component (B) is too low, it will not achieve the purpose of improving thickness consistency and overall dielectric constant consistency; if the proportion of component (B) is too high, it is easy to cause no flow, resulting in voids and low peel strength in the board. Voids will also lead to poor thickness consistency and overall dielectric constant consistency.

[0032] As a preferred embodiment of the present invention, the polybutadiene resin is selected from any one or a combination of at least two of the following: 1,2-polybutadiene resin, maleic anhydride-modified polybutadiene resin, acrylate-modified polybutadiene resin, epoxy-modified polybutadiene resin, amino-modified polybutadiene resin, carboxyl-terminated polybutadiene resin, or hydroxyl-terminated polybutadiene resin.

[0033] As a preferred embodiment of the present invention, the polybutadiene copolymer resin is selected from any one or a combination of at least two of the following: polybutadiene-styrene copolymer resin, styrene-butadiene-styrene copolymer resin, styrene-(ethylene-butene)-styrene copolymer resin, polybutadiene-styrene-divinylbenzene graft copolymer resin, maleic anhydride modified styrene-butadiene copolymer resin, or acrylate modified styrene-butadiene copolymer resin.

[0034] As a preferred embodiment of the present invention, the flame retardant is 5 to 15 parts by weight, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 parts, based on 100 parts by weight of the resin composition.

[0035] Preferably, the flame retardant includes a bromine-containing flame retardant and / or a phosphorus-containing flame retardant.

[0036] Preferably, the bromine-containing flame retardant is selected from any one or a combination of at least two of decabromodiphenyl ether, decabromodiphenyl ethane, or ethylenebistetrabromophthalimide.

[0037] Preferably, the phosphorus-containing flame retardant is selected from any one or a combination of at least two of tris(2,6-dimethylphenyl)phosphine, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide, 2,6-bis(2,6-dimethylphenyl)phosphinobenzene, or 10-phenyl-9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide.

[0038] As a preferred embodiment of the present invention, the silane coupling agent is a vinylsilane coupling agent.

[0039] Based on 100 parts by weight of the resin composition, the silane coupling agent is 0.1 to 1 part by weight, for example, it can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.

[0040] In this invention, the free radical initiator is selected from carbon-based free radical initiators or compound free radical initiators.

[0041] As a preferred embodiment of the present invention, based on 100 parts by weight of the resin composition, the free radical initiator is 0.1 to 1 part by weight, for example, it can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, etc.

[0042] Preferably, the compound free radical initiator comprises a combination of at least one organic peroxide free radical initiator and at least one carbon-based free radical initiator.

[0043] Preferably, the organic peroxide radical initiator is selected from any one or a combination of at least two of the following: dicumyl peroxide, 1,3-bis(tert-butylperoxide-isopropyl)benzene, 2,5-di-tert-butylperoxide-2,5-dimethylhexane, 2,5-di-tert-butylperoxide-2,5-dimethylhexyne-3, di-tert-butylperoxide, or tert-butylperoxide-isopropylbenzene.

[0044] Preferably, the carbon-based free radical initiator is selected from any one or a combination of at least two of 2,3-dimethyl-2,3-diphenylbutane, 2,3-dimethyl-2,3-bis(4-methylphenyl)butane, 2,3-dimethyl-2,3-bis(4-isopropylphenyl)butane, and 3,4-dimethyl-3,4-diphenylhexane.

[0045] It should be noted that the resin composition of the present invention can also be used in combination with various other polymers, as long as they do not impair the inherent properties of the resin composition. These other polymers include, but are not limited to, liquid crystal polymers, thermoplastic resins, different flame retardant compounds or additives, etc., and can be used alone or in combination as needed.

[0046] It should also be noted that the present invention does not impose any special limitations on the preparation method of the resin composition. Commonly used preparation methods in the art are applicable, including but not limited to: stirring and mixing all components of the resin composition to obtain the resin composition.

[0047] In this invention, the filler particle size is tested using a Malvern 3000 laser particle size analyzer; the number-average molecular weight (Mn) of the thermosetting resin is determined by gel permeation chromatography based on polystyrene calibration, according to GB / T 21863-2008; the filler purity is tested using inductively coupled plasma optical emission spectrometry (ICP), by measuring the unique spectral lines and intensities of each element and comparing them with standard solutions to determine the types and contents of elements contained in the sample; the filler conductivity is tested using the mixed liquid method, which involves measuring the conductivity of the mixed liquid using a conductivity meter and then calculating the filler conductivity based on factors such as pH and solute concentration.

[0048] In a second aspect, the present invention provides a dielectric substrate comprising a reinforcing material and a resin composition as described in the first aspect coated on the reinforcing material.

[0049] As a preferred embodiment of the present invention, the reinforcing material is electronic-grade glass fiber cloth.

[0050] Preferably, the reinforcing material is glass fiber cloth surface-treated with vinyl silane coupling agent.

[0051] Thirdly, the present invention provides a circuit material, the circuit material comprising a dielectric substrate as described in the second aspect and a conductive metal layer stacked on one or both sides of the dielectric substrate.

[0052] Preferably, the conductive metal layer is copper foil.

[0053] Preferably, the thickness of the copper foil is 9 to 150 μm, such as 9 μm, 20 μm, 30 μm, 40 μm, 50 μm, 70 μm, 90 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm.

[0054] The present invention uses the resin composition described herein to enable the circuit material prepared therefrom to have a dielectric constant Dk≥4.4 and a dielectric loss Df≤0.0030 at a frequency of 10GHz.

[0055] It should be noted that there are no specific limitations on the preparation method of the circuit material in this invention. For example, the preparation method of the circuit material includes the following steps:

[0056] (1) Dissolve or disperse the resin components in a solvent to obtain a resin solution. Impregnate the reinforcing material with the resin solution, dry it, and then remove the solvent to obtain a prepreg.

[0057] (2) At least one prepreg is stacked together, and a conductive metal layer is provided on one or both sides of its surface. Then, it is placed in a laminator and cured by hot pressing to obtain the circuit material.

[0058] It should be noted that the present invention does not impose any special limitations on the solvent used in step (1). Commonly used organic solvents in the art are applicable, including but not limited to: alcohols such as methanol, ethanol, and butanol; ethers such as ethyl cellosolve, butyl cellosolve, ethylene glycol methyl ether, diethylene glycol ethyl ether, and diethylene glycol butyl ether; ketones such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and mesitylene; esters such as ethoxyethyl acetate and ethyl acetate; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. One of the above solvents can be used alone, or two or more can be used in combination.

[0059] Based on 100 parts by weight of the resin composition, the solvent is 40 to 120 parts by weight, for example, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 parts by weight.

[0060] Fourthly, the present invention provides a printed circuit board comprising a dielectric substrate as described in the second aspect and / or a circuit material as described in the third aspect.

[0061] Preferably, the printed circuit board is a high-frequency substrate.

[0062] In this invention, high-frequency substrate refers to a special circuit board with a high radio frequency, specifically defined as a substrate with a frequency of 1 GHz or higher.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] (1) By designing the specific composition of the resin composition, the present invention further uses rutile titanium dioxide filler with a median D50 particle size of 3 to 6 μm and amorphous fused silica filler with a median D50 particle size of 8 to 12 μm to compound the resin composition and controls the content of thermosetting resin within a specific range. The resulting circuit material has a high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant and good thickness consistency, and is suitable for preparing high frequency substrates.

[0065] (2) The present invention uses a combination of a first thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol), and a second thermosetting resin, polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol), and controls the amount of both added to ensure that the high-frequency substrate has good thickness consistency and overall dielectric constant consistency, and the board has high peel strength.

[0066] (3) The present invention controls the purity of rutile titanium dioxide and amorphous molten silicon dioxide to ≥99.5%, which is the key to ensuring that the circuit material has low dielectric loss and ensures that the dielectric loss Df of the dielectric substrate is ≤0.0030.

[0067] (4) This invention controls the particle size of high-density rutile titanium dioxide to a smaller particle size and the particle size of relatively low-density amorphous molten silica to a larger particle size. Through a large number of experiments and ingenious design, two functional fillers with different densities, particle sizes and dielectric constants are compounded. Within a specific range, the adhesive solution is uniform and does not settle, making it easy to apply. The dielectric constant of the final board is stable and the thickness is consistent. Moreover, the dielectric constant of the board can be adjusted within a certain range without affecting the stability of the production process. Detailed Implementation

[0068] 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.

[0069] The sources of some components in the examples and comparative examples are shown in Table 1 below:

[0070] Table 1

[0071]

[0072]

[0073] Examples 1-8

[0074] Examples 1-8 provide a circuit material and a method for preparing the same, wherein the circuit material includes a dielectric substrate layer, a conductive metal layer, and conductive metal layers on both sides of the dielectric substrate layer;

[0075] The dielectric substrate layer includes a reinforcing material (1080) and a resin composition coated on the reinforcing material. The specific composition of the resin composition is shown in Table 2 below. In Table 2, the amount of resin composition is in parts by weight.

[0076] The preparation method of the above circuit material is as follows:

[0077] (1) The resin composition is dissolved or dispersed in xylene to obtain a resin solution (solid content 65%). The reinforcing material is impregnated with the resin solution, dried and the solvent is removed to obtain a bonding sheet.

[0078] (2) Take 6 adhesive sheets, press a copper foil onto each of their two sides, place them in a laminator, and apply a pressure of 60 kg / cm² at a temperature of 245°C. 2 The circuit material is obtained by hot pressing and curing.

[0079] Comparative Examples 1-6

[0080] Comparative Examples 1-6 provide a circuit material and its preparation method, respectively. The specific composition of the resin composition is shown in Table 3 below. The amount of resin composition in Table 3 is in parts by weight.

[0081] The circuit materials described in Comparative Examples 1-6 can be prepared using the preparation methods provided in the above embodiments.

[0082] Table 2

[0083]

[0084]

[0085] Table 3

[0086]

[0087]

[0088] The performance of the circuit materials (board materials) provided in the above embodiments and comparative examples was tested, and the specific test methods are as follows:

[0089] (1) Dielectric constant (Dk) and dielectric loss (Df): The dielectric constant (Dk) and dielectric loss (Df) of the substrate were tested at a frequency of 10 GHz using the SPDR method.

[0090] (2) Peel strength (PS): The peel strength of the sheet was tested according to the experimental conditions of “after thermal stress” in IPC-TM-650 2.4.8. The unit of peel strength is N / mm.

[0091] (3) Thickness consistency: Five samples were taken from the four corners and the middle of the board to test the thickness of the board. If the thickness of the board meets the third-level tolerance of copper clad laminate, the thickness consistency is good. If the thickness of the board does not meet the third-level tolerance of copper clad laminate, the thickness consistency is poor.

[0092] (4) Dk consistency: Take five samples from the four corners and the middle of the board to test the Dk of the board. If the Dk range of the board is less than or equal to 0.05, the Dk consistency is good. If the Dk range of the board is greater than 0.05, the Dk consistency is poor.

[0093] The performance test results are detailed in Table 3 below:

[0094] Table 3

[0095]

[0096]

[0097] As can be seen from the above, by designing the specific composition of the resin composition in this invention, and further by using rutile titanium dioxide filler with a median D50 particle size of 3-6 μm and amorphous fused silica filler with a median D50 particle size of 8-12 μm for compounding, and controlling the content of thermosetting resin within a specific range, the circuit material prepared has a high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant and good thickness consistency. It is suitable for preparing high-frequency substrates with a dielectric constant (Dk, 10GHz) ≥ 4.4, dielectric loss (Df, 10GHz) ≤ 0.003, peel strength (PS) of 0.75-0.85 N / mm, good thickness consistency, and good Dk consistency.

[0098] A comparison of the data from Examples 1-6 and Examples 7-8 shows that, by controlling the mass ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol) to the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol) within a specific range, the performance of the resin composition is further improved, and a circuit material with excellent performance is prepared.

[0099] As can be seen from the comparison between Example 3 and Comparative Example 1, when the number average molecular weight Mn of the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin is <15000g / mol, the resin is prone to flow and grooves are generated during pressing, resulting in poor thickness uniformity of the board, which in turn leads to poor Dk uniformity of the board.

[0100] As can be seen from the comparison between Example 3 and Comparative Examples 2 and 4, when the particle size of rutile titanium dioxide and amorphous fused silica is small, the oil absorption value of the filler is high, the substrate is prone to voids, which leads to poor dielectric constant stability of the dielectric substrate and also reduces the copper foil peel strength of the board.

[0101] As can be seen from the comparison between Example 3 and Comparative Examples 3 and 5, when the particle size of rutile titanium dioxide and amorphous fused silica is large, the adhesive flow during pressing will be large, especially when pressing thick plates, which is prone to creating grooves, resulting in poor thickness uniformity of the dielectric substrate. Poor thickness uniformity further leads to poor Dk uniformity of the board.

[0102] As can be seen from the comparison between Example 3 and Comparative Examples 6-7, when the purity of rutile titanium dioxide and amorphous fused silica is less than 99.5%, the dielectric loss (Df, 10 GHz) of the dielectric substrate will be greater than 0.003.

[0103] As can be seen from the comparison between Example 3 and Comparative Example 8, when the addition ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol) to the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol) is too high, it will lead to excessive resin flow, affecting the uniformity of the board thickness and the uniformity of the overall dielectric constant.

[0104] As can be seen from the comparison between Example 3 and Comparative Example 9, when the addition ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol) to the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol) is too low, the resin cannot fill the gaps between the fillers, which easily forms voids, resulting in voids in the board and low peel strength. Voids also lead to poor thickness uniformity and poor uniformity of the dielectric constant of the whole board.

[0105] In summary, by designing the specific composition of the resin composition, this invention has prepared a resin composition with excellent performance. The circuit material prepared by the resin composition has a high dielectric constant, low dielectric loss, high copper foil peel strength, stable dielectric constant, and good thickness uniformity.

[0106] The applicant declares that the present invention is illustrated through the above embodiments to describe the resin composition, circuit material comprising the resin, and 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 resin composition, characterized in that, The resin composition comprises the following components: (A) A first thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, having a number-average molecular weight Mn ≤ 5000 g / mol; (B) A second thermosetting resin, including polybutadiene resin and / or polybutadiene copolymer resin, having a number average molecular weight Mn ≥ 15000 g / mol; (C) The first filler consists of rutile titanium dioxide with a particle size D50 of 3~6 μm and a purity ≥99.5%; (D) The second filler comprises amorphous fused silica with a particle size D50 of 8–12 μm and a purity ≥99.5%; (E) Flame retardants; (F) Silane coupling agent; (G) Free radical initiator; Based on 100 parts by weight of the resin composition, the sum of the weight parts of component (A) and component (B) is 18 to 24 parts. The mass ratio of component (A) to component (B) is 1:(0.5~2).

2. The resin composition according to claim 1, characterized in that, Based on 100 parts by weight of the resin composition, the component (C) comprises 14 to 45 parts by weight.

3. The resin composition according to claim 1, characterized in that, Based on 100 parts by weight of the resin composition, the component (D) comprises 25 to 55 parts by weight.

4. The resin composition according to claim 1, characterized in that, The polybutadiene resin is selected from any one or a combination of at least two of the following: 1,2-polybutadiene resin, maleic anhydride-modified polybutadiene resin, acrylate-modified polybutadiene resin, epoxy-modified polybutadiene resin, amino-modified polybutadiene resin, carboxyl-terminated polybutadiene resin, or hydroxyl-terminated polybutadiene resin.

5. The resin composition according to claim 1, characterized in that, The polybutadiene copolymer resin is selected from any one or a combination of at least two of the following: polybutadiene-styrene copolymer resin, styrene-butadiene-styrene copolymer resin, styrene-(ethylene-butene)-styrene copolymer resin, polybutadiene-styrene-divinylbenzene graft copolymer resin, maleic anhydride modified styrene-butadiene copolymer resin, or acrylate modified styrene-butadiene copolymer resin.

6. The resin composition according to claim 1, characterized in that, The electrical conductivity of the rutile titanium dioxide is ≤10 μS / cm.

7. The resin composition according to claim 1, characterized in that, The conductivity of the amorphous molten silica is ≤10 μS / cm.

8. The resin composition according to claim 1, characterized in that, Based on 100 parts by weight of the resin composition, the flame retardant comprises 5 to 15 parts by weight.

9. The resin composition according to claim 1, characterized in that, The flame retardant includes bromine-containing flame retardants and / or phosphorus-containing flame retardants.

10. The resin composition according to claim 9, characterized in that, The bromine-containing flame retardant is selected from any one or a combination of at least two of decabromodiphenyl ether, decabromodiphenyl ethane, or ethylenebistetrabromophthalimide.

11. The resin composition according to claim 9, characterized in that, The phosphorus-containing flame retardant is selected from any one or a combination of at least two of the following: tris(2,6-dimethylphenyl)phosphine, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide, 2,6-bis(2,6-dimethylphenyl)phosphinobenzene, or 10-phenyl-9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide.

12. The resin composition according to claim 1, characterized in that, The silane coupling agent is a vinylsilane coupling agent.

13. The resin composition according to claim 1, characterized in that, Based on 100 parts by weight of the resin composition, the silane coupling agent comprises 0.1 to 1 part by weight.

14. The resin composition according to claim 1, characterized in that, The free radical initiator is a carbon-based free radical initiator or a compound free radical initiator.

15. The resin composition according to claim 1, characterized in that, Based on 100 parts by weight of the resin composition, the free radical initiator is 0.1 to 1 part by weight.

16. The resin composition according to claim 14, characterized in that, The compound free radical initiator includes a combination of at least one organic peroxide free radical initiator and at least one carbon-based free radical initiator.

17. The resin composition according to claim 16, characterized in that, The organic peroxide radical initiator is selected from any one or a combination of at least two of the following: dicumyl peroxide, 1,3-bis(tert-butylperoxide-isopropyl)benzene, 2,5-di-tert-butylperoxide-2,5-dimethylhexane, 2,5-di-tert-butylperoxide-2,5-dimethylhexyn-3, di-tert-butylperoxide, or tert-butylperoxide-isopropylbenzene.

18. The resin composition according to claim 14, characterized in that, The carbon-based free radical initiator is selected from any one or a combination of at least two of 2,3-dimethyl-2,3-diphenylbutane, 2,3-dimethyl-2,3-di(4-methylphenyl)butane, 2,3-dimethyl-2,3-di(4-isopropylphenyl)butane, and 3,4-dimethyl-3,4-diphenylhexane.

19. A dielectric substrate, characterized in that, The dielectric substrate includes a reinforcing material and a resin composition as described in any one of claims 1-18 coated on the reinforcing material.

20. The dielectric substrate according to claim 19, characterized in that, The reinforcing material is electronic-grade glass fiber cloth.

21. The dielectric substrate according to claim 19, characterized in that, The reinforcing material is fiberglass cloth surface-treated with vinyl silane coupling agent.

22. A circuit material, characterized in that, The circuit material includes a dielectric substrate as described in any one of claims 19-21 and a conductive metal layer stacked on one or both sides of the dielectric substrate.

23. The circuit material according to claim 22, characterized in that, The conductive metal layer is copper foil.

24. A printed circuit board, characterized in that, The printed circuit board includes a dielectric substrate as claimed in any one of claims 19-21 and / or the circuit material as claimed in claim 22 or 23.

25. The printed circuit board according to claim 24, characterized in that, The printed circuit board is a high-frequency substrate.

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