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 calcium titanate, particle size D50 is 6~10 μm, purity ≥99.5%;Optional (D) second filler, including amorphous fused silica, particle size 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, dielectric constant is stable and thickness consistency is good.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic materials, and particularly relates to a resin composition, a circuit material comprising the same, and a printed circuit board. BACKGROUND

[0002] In recent years, portable terminals such as smartphones are becoming popular, and in addition, technological innovations such as IoT (Internet of Things) are advancing, as a result of which, household appliances and electronic devices with wireless communication functions have been increasing. This has led to an increase in the amount of communication information in wireless networks, and in order to ensure communication speed and communication quality, the development of the 5th generation mobile communication system (5G for short) is being promoted, and is currently being gradually applied. In 5G, multiple antenna elements are used for highly directional beamforming and spatial reuse, and in addition to the signals of the frequency band of 6 GHz that has been used in the past, signals of a higher frequency band such as the millimeter wave band are also used, so that high-speed communication and improved communication quality can be expected. In 5G, the antenna module needs to be able to cope with high-frequency signals, and for this reason, the dielectric loss tangent (Df) of the dielectric substrate is particularly required to be low at high frequencies.

[0003] Due to the linearity of high-frequency radio waves, signals carried on high-frequency radio waves tend to be easily blocked by obstacles such as buildings. Therefore, in order to avoid this blockage, multiple antenna devices are mounted on the antenna module. Since increasing the relative dielectric constant (Dk) of the substrate material can miniaturize the antenna device, increasing the relative dielectric constant (Dk) is effective for the multiple mounting of antenna devices, and also leads to the miniaturization of the antenna module, and further to the miniaturization of the communication device. Therefore, the dielectric substrate used in the antenna module that can cope with high-frequency signals is required to have a prescribed size of the relatively high dielectric constant (Dk), and the dielectric loss tangent (Df) is required to be low.

[0004] Microstrip antenna is a kind of antenna form developed in the early 1970s. Due to its simple structure, low profile, light weight, conformal installation with aircraft surface and integration with microstrip circuit, it has been widely used in communication, radar and other fields. However, since microstrip antenna is a resonant structure, its structure size is usually large when it is applied to lower frequencies, which cannot meet the requirements of small size. In recent years, the continuous development of wireless communication systems has put forward higher requirements for personal communication terminal modules. For example, with the increasing role of GPS and Beidou systems in real life, radio frequency front-end modules are increasingly portable: light, thin, short and small. Therefore, how to solve the problem of miniaturization of microstrip antenna has become one of the main research topics of microstrip antenna.

[0005] At present, the main methods of microstrip antenna miniaturization include the use of special dielectric substrate, loading short-circuit probe, surface slotting, adding active network, using special microstrip patch form and other schemes. A commonly used method is to use a dielectric substrate with high dielectric constant to reduce the size of the microstrip antenna, but the main defect of this kind of high dielectric constant dielectric antenna is that it excites strong surface wave, the surface loss is large, the gain is reduced, and the efficiency is reduced. In order to improve the gain, the antenna surface is often covered with high dielectric constant medium, but this increases the thickness of the antenna.

[0006] According to the basic theory and design of microstrip antenna, the use of dielectric substrate with high dielectric constant (Dk) can reduce the size of the antenna, and the use of high dielectric constant medium on the surface of the antenna can increase the thickness, thereby increasing the radiation efficiency and improving the antenna gain.

[0007] In the design of the antenna, the stability and consistency of the dielectric constant and thickness of the dielectric substrate material are important indicators that affect the gain and other performances of the antenna. The thickness variation of the dielectric substrate will cause the efficiency of the antenna to decrease. In the design of the antenna, the thickness deviation of the dielectric layer is a more important factor than the stability of the dielectric constant on the efficiency of the antenna. At the same time, the thickness deviation will also cause the resin content to be different, and the difference in resin content will also directly affect the stability of the dielectric constant.

[0008] When manufacturing thick dielectric substrates, in order to ensure the uniformity of the thickness, a large amount of filler and resin with large molecular weight are used to increase the dielectric constant (Dk) and reduce the flow of glue, which will cause the copper foil peeling strength of the dielectric substrate to be low, and even the dielectric substrate will have voids, thereby further causing the poor stability of the dielectric constant of the dielectric substrate.

[0009] In summary, in order to cope with the high frequency of the antenna module, the dielectric loss tangent (Df) of the dielectric substrate must be low; in order to miniaturize the antenna module and further miniaturize the communication device, the dielectric substrate must have a relatively high dielectric constant (Dk) of a specified size; the use of dielectric substrate with high dielectric constant (Dk) can reduce the size of the antenna, and in order to improve the gain, the thickness of the antenna must be increased, thereby increasing the thickness of the dielectric substrate; after the thickness of the dielectric substrate is increased, the stability and consistency of the dielectric constant and thickness of the dielectric substrate material will face many challenges. In order to ensure the uniformity of the thickness, a large amount of filler and resin with large molecular weight are used to increase the dielectric constant (Dk) and reduce the flow of glue, which will cause the copper foil peeling strength of the dielectric substrate to be low.

[0010] Therefore, how to provide a resin composition with excellent performance, which can be used to prepare a circuit material with high dielectric constant, low dielectric loss, high copper foil peeling strength, stable dielectric constant and good thickness consistency, has become a technical problem to be solved at present. SUMMARY

[0011] In view of the deficiencies of the prior art, the present application aims to provide a resin composition, a circuit material comprising the same, and a printed circuit board. By designing the specific composition of the resin composition, a resin composition with excellent performance is prepared, and the circuit material prepared therefrom has a high dielectric constant, a low dielectric loss, a high copper foil peeling strength, a stable dielectric constant, and good thickness consistency.

[0012] To achieve this goal, the present application adopts the following technical solutions:

[0013] In one aspect, the present application provides a resin composition comprising the following components:

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

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

[0016] (C) a first filler comprising calcium titanate, with a particle size D50 of 6-10 μm and a purity ≥99.5%;

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

[0018] (E) a flame retardant;

[0019] (F) a silane coupling agent;

[0020] (G) a free radical initiator.

[0021] In the present application, the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin has a number average molecular weight Mn≤5000 g / mol, the molecular weight of the first thermosetting resin is lower, mainly providing flow glue and glass cloth infiltration in the formula, improving the density and copper foil peeling strength of the plate. In the present application, 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. In the present application, the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin has a number average molecular weight Mn≥15000 g / mol, the molecular weight of the second thermosetting resin is higher, mainly adjusting the flow glue size in the formula, when the formula flow glue is larger, the proportion of the second thermosetting resin needs to be increased to reduce the flow glue, when the formula flow glue is smaller, the proportion of the second thermosetting resin needs to be reduced to increase the flow glue. In the present application, 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.

[0022] In the present application, the first filler calcium titanate has a particle size D50 of 6-10 μm and a purity ≥99.5%. Calcium titanate is a cubic crystal system, which is a typical representative of perovskite structure. Due to its structural characteristics, the interaction of titanium ions in the titanium-oxygen octahedron in the perovskite lattice structure produces a large internal electric field, so it has a relatively high relative dielectric constant, with a dielectric constant of 150-160. Therefore, in order to further improve the dielectric constant of the dielectric substrate, the use of calcium titanate to improve the dielectric constant is more obvious.

[0023] In the present application, the median particle size D50 of the calcium titanate filler can be 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc. If the particle size D50 of the calcium titanate is less than 6 μm, the oil absorption value of the filler is high, the viscosity of the glue solution is too high to affect the processability of the gluing, resulting in uneven thickness of the plate, and also causing the plate to flow small, resulting in low copper foil peeling strength; if the particle size D50 of the calcium titanate is greater than 10 μm, the calcium titanate is easy to settle because of its large density (4.1 g / cm 3 ) and the filler is not uniformly dispersed, ultimately resulting in unstable dielectric constant and poor consistency of the dielectric substrate, and also causing the formation of plate edge gullies when the thick plate is pressed due to large flow, resulting in uneven thickness of the plate, and also causing unstable dielectric constant and poor consistency. Especially when the customer needs very thick specifications such as 30 mil (0.762 mm), 40 mil (1.016 mm), 80 mil (2.032 mm), 160 mil (4.064 mm), 240 mil (6.096 mm), etc., the control of the uniformity of the whole plate thickness of the plate is more critical.

[0024] In the present application, the inventors have found through a large number of experimental studies that the purity of calcium titanate will affect the dielectric loss of the dielectric substrate, especially when the proportion of calcium titanate in the formula is high, the effect on the dielectric loss of the dielectric substrate is more obvious, when the purity is ≥ 99.5%, the soluble conductive substances or impurities in the filler are relatively less, so the dielectric loss of the dielectric substrate is relatively small. In order to further control the dielectric loss of the dielectric substrate, the conductivity of the calcium titanate is further optimized to be ≤ 10 μS / cm, 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.

[0025] In the present application, the optional (D) second filler means that the resin composition can not contain the second filler, or can contain the second filler.

[0026] In the present application, the second filler amorphous fused silica has a particle size D50 of 8-12 μm and a purity ≥99.5%. The dielectric constant of the amorphous fused silica is 3.6-3.8. The main role of the amorphous fused silica in the formula is to adjust the dielectric constant of the dielectric substrate. When the dielectric constant Dk of the dielectric substrate is ≥10, the addition ratio of calcium titanate in the formula is relatively high, and the amorphous fused silica can be optionally added or added in a relatively low ratio. In the present application, 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 the present application, the inventors have found through a large number of experimental studies that when the resin formula in the present application is used, if the particle size D50 of the amorphous fused silica is less than 8 μm and is used in combination with a relatively high addition ratio of calcium titanate, the increase in the viscosity of the glue solution will affect the gluing process, and the filler has a large oil absorption value, the substrate is prone to cavities, resulting in poor dielectric constant stability of the dielectric substrate, and also reducing the copper foil peel strength of the board. If the particle size D50 of the amorphous fused silica is greater than 12 μm, the flow of the pressed board will be large, especially when thick boards are pressed, which is prone to cause gullies, resulting in poor thickness consistency of the dielectric substrate. In order to obtain a lower dielectric loss, the purity of the amorphous fused silica used is ≥99.5%, and in order to further obtain a lower dielectric loss, the conductivity of the amorphous fused silica is preferably ≤10 μS / cm, 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.

[0027] In the present application, the sum of the weight parts of components (A) and (B) is 18-25 parts by weight (for example, 18 parts, 19 parts, 20 parts, 22 parts, 24 parts, or 25 parts, etc.), the amount of component (C) is 60-70 parts by weight (for example, 60 parts, 62 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, or 70 parts, etc.), and the amount of component (D) is 0-15 parts by weight (for example, 0 parts, 0.5 parts, 1 part, 2 parts, 5 parts, 8 parts, 9 parts, 10 parts, 12 parts, 14 parts, or 15 parts, etc.), all based on 100 parts by weight of the resin composition. If the content of the resin (components (A) and (B)) is too low, the resin cannot fill the voids between the fillers, and voids are easily formed, resulting in poor thickness uniformity and poor uniformity of the dielectric constant of the entire board. If the content of components (A) and (B) is too high, the glue flow will be too large, affecting the thickness uniformity and the dielectric constant uniformity of the entire board. Component (C), calcium titanate, has a relatively high dielectric constant, with a dielectric constant of 150-160, while component (D), amorphous fused silica, has a relatively low dielectric constant, with a dielectric constant of 3.6-3.8. By adjusting the amounts of components (C) and (D), different dielectric constants of the dielectric substrate with a dielectric constant Dk≥10 can be achieved.

[0028] The following are preferred technical solutions of the present application, but are not intended to limit the technical solutions provided by the present application. Through the following preferred technical solutions, the purposes and beneficial effects of the present application can be better achieved and realized.

[0029] As a preferred technical solution of the present application, 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.

[0030] Because the molecular weight of the component (A) first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000 g / mol) is small, it will flow when heated and pressurized alone, and it is easy to produce grooves and other apparent defects, and the thickness of the board edge position is thin, the thickness of the whole board is unstable, which will lead to the poor consistency of the dielectric constant of the whole board. In order to ensure that the high-frequency substrate has good thickness consistency and whole board dielectric constant consistency, in the present application, component (B) second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000 g / mol) is added to the formula, which can ensure that the high-frequency substrate has good thickness consistency and whole board dielectric constant consistency. When the mass ratio of component (A) and component (B) is 1:(0.5-2), the effect is best. If the proportion of component (B) is too low, it cannot improve the thickness consistency and whole board dielectric constant consistency; if the proportion of component (B) is too high, it is easy to appear no flow, which leads to the appearance of voids and low peeling strength in the board, and the voids also lead to poor thickness consistency and whole board dielectric constant consistency.

[0031] As a preferred technical solution of the present application, the polybutadiene resin is selected from any one or a combination of at least two of 1,2-polybutadiene resin, maleic anhydride modified polybutadiene resin, acrylate modified polybutadiene resin, epoxy modified polybutadiene resin, amine group modified polybutadiene resin, carboxyl-terminated modified polybutadiene resin or hydroxyl-terminated modified polybutadiene resin;

[0032] As a preferred technical solution of the present application, the polybutadiene copolymer resin is selected from any one or a combination of at least two of polybutadiene-styrene copolymer resin, styrene-butadiene-styrene copolymer resin, styrene-(ethylene-butylene)-styrene copolymer resin, polybutadiene-styrene-divinylbenzene graft copolymer resin, maleic anhydride modified styrene-butadiene copolymer resin or acrylate modified styrene-butadiene copolymer resin.

[0033] As a preferred technical solution of the present application, the weight fraction of the flame retardant is 5-15 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts, etc., based on 100 parts of the weight fraction of the resin composition.

[0034] Preferably, the flame retardant includes a bromine-containing flame retardant and / or a phosphorus-containing flame retardant.

[0035] Preferably, the bromine-containing flame retardant is selected from any one or a combination of at least two of decabromodiphenyl ether, decabromodiphenyl ethane or ethylene bis-tetrabromophthalimide.

[0036] 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-phosphaphenanthrene-10-oxide, 2,6-bis(2,6-dimethylphenyl)phosphinobenzene, or 10-phenyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0037] As a preferred technical solution of the present application, the silane coupling agent is a vinyl silane coupling agent.

[0038] The silane coupling agent is 0.1 to 1 parts by weight, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, or 1 part, etc., based on 100 parts by weight of the resin composition.

[0039] In the present application, the free radical initiator is a carbon-based free radical initiator or a compounded free radical initiator.

[0040] As a preferred technical solution of the present application, the free radical initiator is 0.1 to 1 parts by weight, for example, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, or 1 part, etc., based on 100 parts by weight of the resin composition.

[0041] Preferably, the compounded free radical initiator comprises a combination of at least one organic peroxide free radical initiator and at least one carbon-based free radical initiator.

[0042] Preferably, the organic peroxide free radical initiator is selected from any one or a combination of at least two of dicumyl peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-di-tert-butylperoxy-2,5-dimethylhexane, 2,5-di-tert-butylperoxy-2,5-dimethylhexyne-3, di-tert-butyl peroxide, or tert-butylcumyl peroxide.

[0043] 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-di(4-methylphenyl)butane, 2,3-dimethyl-2,3-di(4-isopropylphenyl)butane, 3,4-dimethyl-3,4-diphenylhexane.

[0044] It should be noted that the resin composition of the present application can also be used in combination with other various polymers, as long as it does not impair the inherent properties of the resin composition, which exemplarily includes but is 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.

[0045] It should also be noted that the preparation method of the resin composition in the present application is not subject to any special restriction, and the commonly used preparation methods in the art are applicable, which exemplarily includes but is not limited to: stirring and mixing all components of the resin composition to obtain the resin composition.

[0046] In the present application, the filler particle size test method is tested by Malven 3000 laser particle size analyzer; the test method of the number average molecular weight Mn of the thermosetting resin is GB / T 21863-2008, which is determined by gel permeation chromatography based on polystyrene calibration; the filler purity test method is tested by inductively coupled plasma optical emission spectrometry (ICP), by measuring the specific spectral line and intensity of each element, and comparing with the standard solution, the type and content of the elements contained in the sample can be obtained; the filler conductivity test method adopts mixed liquid method, which is to measure the conductivity of mixed liquid by conductivity meter, and then calculate the conductivity of the filler according to the pH value and solute concentration.

[0047] In the second aspect, the present application provides a dielectric substrate, which comprises a reinforcing material and a resin composition as described in the first aspect coated on the reinforcing material.

[0048] As a preferred technical solution of the present application, the reinforcing material is an electronic grade glass fiber cloth.

[0049] Preferably, the reinforcing material is a glass fiber cloth treated with a vinyl silane coupling agent.

[0050] In the third aspect, the present application provides a circuit material, which comprises a dielectric substrate layer as described in the second aspect and a conductive metal layer laminated on one side or both sides of the dielectric substrate layer.

[0051] Preferably, the conductive metal layer is a copper foil.

[0052] Preferably, the thickness of the copper foil is 9-150 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, etc.

[0053] The resin composition can make the circuit material prepared therefrom have a dielectric constant Dk≥10 and a dielectric loss Df≤0.0030 at a frequency of 10 GHz.

[0054] It should be noted that the preparation method of the circuit material in the present application is not subject to any specific limitation, and the preparation method of the circuit material exemplarily comprises the following steps:

[0055] (1) dissolving or dispersing the resin composition in a solvent to obtain a resin glue solution, impregnating a reinforcing material with the resin glue solution, and then drying and removing the solvent to obtain a prepreg;

[0056] (2) stacking at least one prepreg together, arranging a conductive metal layer on one side or both sides of the surface of the prepreg, and then placing the prepreg into a laminator to be cured by hot pressing to obtain the circuit material.

[0057] It should be noted that the solvent in step (1) is not subject to any special limitation, and any commonly used organic solvent in the art is suitable, exemplarily 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. The above-mentioned solvents can be used singly or in combination of two or more.

[0058] The weight fraction of the solvent is 40-120 parts, for example, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, or 120 parts, etc., based on 100 parts of the resin composition.

[0059] In a fourth aspect, the present application provides a printed circuit board, which comprises the dielectric substrate according to the second aspect and / or the circuit material according to the third aspect.

[0060] Preferably, the printed circuit board is a high-frequency substrate.

[0061] In the present application, the high-frequency substrate refers to a special circuit board with a relatively high radio frequency, specifically defined as a substrate with a frequency of 1 GHz or higher.

[0062] Compared with the prior art, the present application has the following beneficial effects:

[0063] (1) The application designs the specific composition of the resin composition, further compounding calcium titanate fillers with a median particle size D50 of 6-10 μm and amorphous fused silica fillers with a median particle size D50 of 8-12 μm, and controlling the content of the thermosetting resin within a specific range, so that the prepared circuit material has high dielectric constant, low dielectric loss, high copper foil peeling strength, stable dielectric constant and good thickness consistency, and is suitable for preparing high-frequency substrates.

[0064] (2) The application uses the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000 g / mol) and the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000 g / mol) in compounding, and controls the addition amount of the two, so that the high-frequency substrate has good thickness consistency and whole plate dielectric constant consistency, and the peeling strength of the plate is high.

[0065] (3) The application controls the purity of calcium titanate and amorphous fused silica to be ≥99.5%, which is the key to ensure that the circuit material has low dielectric loss, and ensures that the dielectric loss Df of the dielectric substrate is ≤0.0030. DETAILED DESCRIPTION

[0066] The technical solutions of the application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application, and should not be regarded as specific limitations on the application.

[0067] The sources of some components in the examples and comparative examples are shown in Table 1.

[0068] Table 1

[0069]

[0070] Examples 1-11

[0071] Examples 1-11 respectively provide a circuit material and a preparation method thereof, the circuit material comprising a dielectric substrate layer, a conductive metal layer, and a conductive metal layer on both sides of the dielectric substrate layer;

[0072] The dielectric substrate layer comprises a reinforcing material and a resin composition coated on the reinforcing material, and the specific composition of the resin composition and the specific composition of the circuit material are shown in Table 2, wherein the unit of the amount of the resin composition in Table 2 is parts by weight, the unit of the reinforcing material is pieces, and the unit of the conductive metal layer is pieces.

[0073] The preparation method of the above-mentioned circuit material is as follows:

[0074] (1) The resin composition is dissolved or dispersed in xylene to obtain a resin glue solution (solid content 65%), and the reinforcing material is impregnated with the resin glue solution, and then dried to remove the solvent to obtain a bonding sheet;

[0075] (2) Six bonding sheets are taken, and one copper foil is respectively attached to the two sides of each bonding sheet, and then placed in a laminator, and then hot-pressed and cured at a temperature of 245°C and a pressure of 60 Kg / cm 2 , to obtain the circuit material.

[0076] Comparative Examples 1-6

[0077] Comparative Examples 1-6 each provide a circuit material and a preparation method thereof, the specific composition of the resin composition and the specific composition of the circuit material are shown in Table 3, and the unit of the resin composition in Table 3 is weight parts.

[0078] The circuit material in Comparative Examples 1-6 is prepared by the preparation method provided in the above examples.

[0079] Table 2

[0080]

[0081]

[0082] Table 3

[0083]

[0084] The performance of the circuit material (board) provided in the above examples and comparative examples is tested, and the specific test method is as follows:

[0085] (1) Dielectric constant (Dk) and dielectric loss (Df): The dielectric constant (Dk) and dielectric loss (Df) of the board are tested at a frequency of 10 GHz by using the SPDR method;

[0086] (2) Peel strength (PS): The peel strength of the board is tested according to the experimental conditions of "after thermal stress" in IPC-TM-650 2.4.8 method, and the unit of the peel strength is N / mm;

[0087] (3) Thickness consistency: five samples are taken at the four corners and the middle position of the board to test the thickness of the board, if the thickness of the board meets the third level tolerance of the copper-clad plate, the thickness consistency is good, if the thickness of the board cannot meet the third level tolerance of the copper-clad plate, the thickness consistency is poor;

[0088] (4) Dk consistency: five samples are taken at 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;

[0089] The performance test results are shown in Table 3 below.

[0090] Table 3

[0091] Dk (10 GHz) Df (10 GHz) Peel strength Thickness uniformity Dk uniformity Example 1 10.0 0.0026 0.82 Good Good Example 2 11.6 0.0027 0.83 Good Good Example 3 13.5 0.0028 0.75 Good Good Example 4 10.5 0.0027 0.72 Good Good Example 5 10.6 0.0027 0.73 Good Good Example 6 12.2 0.0029 0.74 Good Good Example 7 10.2 0.0028 0.81 Poor Poor Example 8 10.1 0.0028 0.53 Good Good Comparative Example 1 10.1 0.0027 0.81 Poor Poor Comparative Example 2 10.0 0.0028 0.52 Good Poor Comparative Example 3 10.2 0.0027 0.79 Poor Poor Comparative Example 4 10.0 0.0028 0.56 Good Poor Comparative Example 5 10.1 0.0027 0.81 Poor Poor Comparative Example 6 13.6 0.0039 0.76 Good Good Comparative Example 7 10.8 0.0035 0.78 Good Good Comparative Example 8 9.6 0.0026 0.77 Poor Poor Comparative Example 9 13.8 0.0029 0.49 Poor Poor

[0092] From the above, in the present application, by designing the specific composition of the resin composition, further by compounding calcium titanate filler with a particle size median D50 of 6-10 μm and amorphous fused silica filler with a particle size median D50 of 8-12 μm, and controlling the content of the thermosetting resin within a specific range, the prepared circuit material has 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, with dielectric constant (Dk, 10 GHz) ≥10, dielectric loss (Df, 10 GHz) ≤0.003, peel strength (PS) of 0.72-0.83 N / mm, good thickness consistency, and good Dk consistency.

[0093] From the comparison of the data of Examples 1-6 and Examples 7-8, in the present application, by controlling the mass ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn ≤5000 g / mol) and the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn ≥15000 g / mol) within a specific range, the performance of the resin composition is further improved, and a circuit material with excellent performance is prepared.

[0094] From the comparison of Example 1 and Comparative Example 1, when the number average molecular weight Mn of the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin is less than 15000 g / mol, the board is prone to flow and gully during pressing, resulting in poor thickness consistency of the board, and the poor thickness consistency further leads to poor Dk consistency of the board.

[0095] From the comparison of Example 1 and Comparative Examples 2 and 4, when the particle size of calcium titanate and the particle size of amorphous fused silica are small, the oil absorption value of the filler is high, the substrate is prone to cavitation, resulting in poor dielectric constant stability of the dielectric substrate, and also reducing the copper foil peel strength of the board.

[0096] From the comparison of Example 1 and Comparative Example 3, Comparative Example 5, it can be seen that when the particle size of calcium titanate and the particle size of amorphous fused silica are large, the flow glue during pressing is large, especially when pressing thick plates, it is easy to produce gullies, resulting in poor thickness consistency of the medium substrate, and poor thickness consistency further leads to poor Dk consistency of the plate.

[0097] From the comparison of Example 3 and Comparative Example 6, Example 5 and Comparative Example 7, it can be seen that when the purity of calcium titanate and amorphous fused silica is less than 99.5%, it will cause the dielectric loss (Df, 10GHz) of the medium substrate to be >0.003.

[0098] From the comparison of Example 1 and Comparative Example 8, it can be seen that when the addition ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol) and the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol) is too large, it will cause the flow glue to be too large, affecting the thickness consistency of the plate and the dielectric constant consistency of the whole plate.

[0099] From the comparison of Example 1 and Comparative Example 9, it can be seen that when the addition ratio of the first thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≤5000g / mol) and the second thermosetting resin polybutadiene resin and / or polybutadiene copolymer resin (number average molecular weight Mn≥15000g / mol) is too small, then the resin cannot fill the voids between the fillers, and it is easy to form voids, resulting in voids and low peeling strength of the plate, and the voids also cause poor thickness consistency and dielectric constant consistency of the whole plate.

[0100] In summary, by designing the specific composition of the resin composition in the present application, a resin composition with excellent performance is prepared, and the circuit material prepared from the resin composition has high dielectric constant, low dielectric loss, high copper foil peeling strength, stable dielectric constant and good thickness consistency.

[0101] The applicant declares that the resin composition of the present application, the circuit material comprising the same and the printed circuit board are illustrated by the above examples, but the present application is not limited to the above examples, i.e. it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application and addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

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, comprising calcium titanate, has a particle size D50 of 6~10 μm and a purity ≥99.5%; Optional (D) second filler, comprising 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 components (A) and (B) is 18 to 25 parts by weight. 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 amount of component (C) is 60 to 70 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 amount of component (D) is 0 to 15 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 conductivity of the calcium titanate 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 16, 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 layer as described in any one of claims 19-21 and a conductive metal layer stacked on one or both sides of the dielectric substrate layer.

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 described in any one of claims 19-21 and / or a circuit material as described 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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