Copper-clad plate, intermediate layer of copper-clad plate, and preparation method and application of intermediate layer

Abstract

The invention discloses a copper-clad plate as well as a middle layer and a preparation method and application thereof, and belongs to the technical field of copper-clad plates. The preparation method of the intermediate layer for the copper-clad plate comprises the following steps: orthogonally weaving PBO fibers and glass fibers to obtain blend fibers; the mass ratio of the PBO fibers to the glass fibers is (10: 90)-(60: 40); carrying out modification treatment on the blend fibers to obtain modified blend fibers; dipping the modified blend fiber in a resin-containing dipping solution; and drying the impregnated modified blend fiber. The preparation method is simple and easy to operate, the PBO fibers and the glass fibers are orthogonally woven according to a specific ratio, so that on one hand, the blend fibers have the advantages of the PBO fibers and the glass fibers, on the other hand, the anisotropy of the blend fibers is effectively optimized, and the obtained copper-clad plate has relatively low dielectric loss and expansion coefficient; the peeling strength, the heat resistance and the flexibility are better.

Description

Technical Field

[0001] The present invention relates to the technical field of copper clad laminates, and in particular to a copper clad laminate and an intermediate layer thereof, and a preparation method and application thereof. Background Art

[0002] Copper clad laminate (CCL) is a core material used in the manufacture of printed circuit boards (PCBs). It consists of an insulating substrate and a copper foil laminate. The insulating substrate is typically made of fiberglass cloth and epoxy resin. However, the glass transition temperature (Tg) of fiberglass-reinforced epoxy resin substrates is typically ≤180°C, which cannot meet the high-temperature requirements of 5G base stations and other applications.

[0003] In addition, the glass fiber used in the prior art to prepare copper clad laminates is prone to problems due to its high dielectric constant and loss factor (such as dielectric constant D k Reaching 6.6, loss factor D f Reaching 0.005) can easily lead to problems such as signal transmission delay and energy loss. In addition, glass fiber is relatively brittle and is prone to wire breakage during processing. Moreover, the linear expansion coefficients of glass fiber and copper foil commonly used in copper clad laminates are quite different (for example, the Z-axis expansion coefficient of glass fiber is 45ppm / °C, and the Z-axis expansion coefficient of copper foil is 17ppm / °C), resulting in a weak interface bond between the two laminates, which is prone to delamination, affecting the actual use of the copper clad laminate.

[0004] Some existing technologies obtain low dielectric copper clad laminates by modifying resins (such as PPO and PTFE systems) or reinforcing single fibers (such as upgrading E-glass to D-glass). f Low (<0.001), but poor peel strength (0.8N / mm) and high CTE (50ppm / ℃), and PTFE copper clad laminates require complex processes (such as two-step lamination) to achieve low Dk, which is costly; aerogel fibers (D k About 2.5 to 3.0) can replace glass fiber, but its mechanical strength is insufficient.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The object of the present invention is to provide a copper clad laminate and an intermediate layer thereof, and a preparation method and application thereof, so as to solve or improve at least one of the above-mentioned technical problems.

[0007] The present invention can be achieved like this:

[0008] In a first aspect, the present invention provides a method for preparing an intermediate layer for a copper clad laminate, comprising the following steps:

[0009] orthogonally weaving PBO fibers and glass fibers to obtain blended fibers; wherein the mass ratio of PBO fibers to glass fibers is 10:90 to 60:40;

[0010] Modifying the blended fiber to obtain modified blended fiber;

[0011] impregnating the modified blended fiber in an impregnation solution containing resin;

[0012] The impregnated modified blended fiber is dried to obtain an intermediate layer for a copper clad laminate.

[0013] In an optional embodiment, the orthogonal weaving adopts a method of vertical weaving in the warp and weft directions, wherein the warp density is 60 to 80 strands / inch, and the weft density is 60 to 80 strands / inch.

[0014] In an optional embodiment, the warp pre-tension is 10N to 15N.

[0015] In an alternative embodiment, the glass fiber has a dielectric loss not exceeding 0.0035 and a dielectric constant not exceeding 6.8.

[0016] In an optional embodiment, the modification treatment includes at least one of plasma treatment, silane coupling agent treatment, and radiation treatment.

[0017] In an optional embodiment, when the modification treatment is plasma treatment, the power of the plasma treatment is 50W to 600W, the treatment time is 1min to 120min, and the treatment atmosphere is an inert atmosphere;

[0018] When the modified silane coupling agent is used, the silane coupling agent includes at least one of KH550, KH792 and KH560;

[0019] When the modification treatment is irradiation treatment, the irradiation energy is 20 kGy to 270 kGy.

[0020] In an optional embodiment, the content of the resin in the impregnating liquid is 35% to 75%.

[0021] In an optional embodiment, the resin includes at least one of PPO resin, hydrocarbon resin, BMI resin and BT resin.

[0022] In an alternative embodiment, the viscosity of the impregnation fluid does not exceed 10,000 cps.

[0023] In an optional embodiment, the impregnation liquid further contains a filler.

[0024] In an optional embodiment, the amount of filler contained in the impregnation liquid is not less than 15 wt %.

[0025] In an alternative embodiment, the filler comprises at least one of silica, aluminum hydroxide, boehmite, and boron nitride.

[0026] In an alternative embodiment, the expansion coefficient of the filler does not exceed 40 ppm.

[0027] In a second aspect, the present invention provides an intermediate layer for a copper clad laminate, which is prepared by the preparation method of any one of the aforementioned embodiments.

[0028] In a third aspect, the present invention provides a copper clad laminate comprising a copper foil and the intermediate layer of any one of the aforementioned embodiments.

[0029] In an optional embodiment, the copper clad laminate has at least one of the following features:

[0030] Feature 1: The dielectric constant of the copper clad laminate is 2.6 to 3.0;

[0031] Feature 2: The dielectric loss of the copper clad laminate does not exceed 0.0016;

[0032] Feature 3: The expansion coefficient of the copper clad laminate in the Z axis does not exceed 25;

[0033] Feature 4: The Tg of the copper clad laminate is not less than 220;

[0034] Feature 5: The peel strength of the copper clad laminate is not less than 1.20.

[0035] In a fourth aspect, the present invention provides a method for preparing a copper clad laminate, comprising: laminating the intermediate layer of the aforementioned embodiment with copper foil.

[0036] In an optional embodiment, the lamination pressure is 25 MPa to 35 MPa, the temperature is 180° C. to 220° C., and the time is 0.5 h to 8 h.

[0037] The beneficial effects of the present invention include:

[0038] The method for preparing an intermediate layer for a copper-clad laminate provided by the present invention is simple and easy to operate. By orthogonally weaving PBO fibers and glass fibers in a specific ratio, the anisotropy of the blended fibers is effectively optimized while also imparting excellent mechanical properties, dielectric properties, heat resistance, and flexibility. The dielectric properties, heat resistance, and strength of the copper-clad laminate can be effectively improved by laminating the intermediate layer with copper foil to prepare the copper-clad laminate.

[0039] The copper-clad laminate prepared by the method not only has a lower dielectric constant, dielectric loss, expansion coefficient and better peeling strength, but also has better heat resistance and flexibility. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0041] The copper clad laminate and its intermediate layer provided by the present invention, as well as its preparation method and application are described in detail below.

[0042] The present invention provides a method for preparing an intermediate layer for a copper clad laminate, comprising the following steps:

[0043] S1: Orthogonally weave PBO fiber and glass fiber to obtain blended fiber.

[0044] The PBO fiber used in the present invention is poly(p-phenylene benzobisoxazole) fiber. By compounding the PBO fiber with the glass fiber to form a blended fiber, the defects of the glass fiber can be improved based on the addition of the PBO fiber, which is beneficial for the blended fiber to have good mechanical properties, dielectric properties, heat resistance and flexibility.

[0045] The mass ratio of the PBO fiber to the glass fiber is 10:90 to 60:40, such as 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45 or 60:40, and may also be other values ​​within the range of 10:90 to 60:40.

[0046] If the amount of PBO fiber is less than 10%, the dielectric properties and mechanical properties of the copper clad laminate cannot be effectively improved; if the amount of PBO fiber is higher than 60%, it is not conducive to improving the interface strength between the fiber and the resin.

[0047] In some optional embodiments, the dielectric loss of the glass fiber does not exceed 0.0035, and the dielectric constant does not exceed 6.8.

[0048] In the present invention, orthogonal weaving adopts a method of vertical weaving in the warp and weft directions, wherein the warp density is 60 to 80 strands / inch, and the weft density is 60 to 80 strands / inch. For example, the warp density and the weft density can independently be 60, 65, 70, 75 or 80 strands / inch, etc., or other values ​​within the range of 60 to 80 strands / inch. The single layers obtained by vertically weaving the warp and weft directions are stacked, with the stacking direction being the Z-axis direction, and the density in the Z-axis direction is 60 to 80 strands / inch. The planes of each layer woven vertically in the warp and weft directions are perpendicular to the Z-axis.

[0049] In the actual weaving process, PBO fibers can be used as warp fibers and glass fibers as weft fibers for orthogonal weaving; or glass fibers can be used as warp fibers and PBO fibers as weft fibers for orthogonal weaving. In some typical embodiments, PBO fibers are used as warp fibers and glass fibers are used as weft fibers for orthogonal weaving.

[0050] In an optional embodiment, the warp pre-tension may be 10N to 15N, such as 10N, 11N, 12N, 13N, 14N, or 15N, or may be other values ​​within the range of 10N to 15N. If the warp pre-tension is lower than 10N, the density will be low; if it is higher than 15N, the weave will be too tight, both of which will affect the performance of the copper clad laminate.

[0051] Continuing from the above, by orthogonally weaving PBO fiber and glass fiber in a specific ratio and stacking them along the Z axis, on the one hand, the anisotropy of the blended fiber is effectively optimized, and on the other hand, the blended fiber can have good mechanical properties, dielectric properties, heat resistance and flexibility.

[0052] S2: modifying the blended fiber to obtain modified blended fiber.

[0053] In some optional embodiments, the modification treatment may include at least one of plasma treatment, silane coupling agent treatment, and irradiation treatment. The above modification treatment can improve the interfacial bonding strength of the material and improve subsequent wettability.

[0054] When the modification treatment is a plasma treatment, the power of the plasma treatment can be 50 W to 600 W, such as 50 W, 100 W, 200 W, 300 W, 400 W, 500 W, or 600 W, or other values ​​within the range of 50 W to 600 W. The plasma treatment time can be 1 min to 120 min, such as 1 min, 5 min, 10 min, 20 min, 50 min, 80 min, 100 min, or 120 min, or other values ​​within the range of 1 min to 120 min. The treatment atmosphere is an inert atmosphere, such as a nitrogen atmosphere or an argon atmosphere.

[0055] When the modification treatment involves a silane coupling agent, a silane coupling agent aqueous solution can be prepared, followed by immersion of the blended fibers in the solution for a period of time, and then removal and drying. The silane coupling agent can illustratively include at least one of KH550, KH792, and KH560. KH550 and KH792 can be used in conjunction with hydrophilic resins, while KH560 can be used in conjunction with highly polar resins. Furthermore, low-polarity resins can be used in conjunction with low-polarity coupling agents. The concentration of the silane coupling agent aqueous solution can range from 4wt% to 6wt%, and the blended fibers can be immersed in the silane coupling agent aqueous solution for 25min to 35min. The drying temperature can range from 75°C to 85°C, and the drying time can range from 0.5h to 2h.

[0056] When the modification treatment is irradiation treatment, the irradiation energy can be 20kGy to 270kGy, such as 20kGy, 50kGy, 80kGy, 100kGy, 120kGy, 150kGy, 180kGy, 200kGy, 220kGy, 250kGy or 270kGy, or other values ​​within the range of 20kGy to 270kGy.

[0057] S3: impregnating the modified blended fiber in an impregnation solution containing resin.

[0058] In some optional embodiments, the resin content in the impregnation solution may be 35% to 75%, such as 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or 75%, or other values ​​within the range of 35% to 75%. The resin may include at least one of PPO resin (poly-2,6-dimethyl-1,4-phenylene ether resin), hydrocarbon resin (olefin resin), BMI resin (bismaleimide resin) and BT resin. BT resin is a thermosetting resin composed of bismaleimide (BMI) and triazine as the main resin components, with epoxy resin, polyphenylene ether resin (PPE) or allyl compound added as a modifying component.

[0059] In some optional embodiments, the impregnation liquid may further contain a filler. The amount of filler in the impregnation liquid is no less than 15wt%, such as 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, or 40wt%. For example, the filler may include at least one of silica, aluminum hydroxide, boehmite, and boron nitride. For example, a combination of SiO2 and boron nitride may be used. The size of the filler may be micrometer-scale or nanometer-scale. In some typical embodiments, the expansion coefficient of the filler does not exceed 40ppm.

[0060] The dielectric constant of the copper clad laminate can be further reduced by using fillers in the impregnation solution.

[0061] In some optional embodiments, the viscosity of the impregnation liquid does not exceed 10,000 cps. In some more typical embodiments, the viscosity of the impregnation liquid does not exceed 2,000 cps.

[0062] S4: Drying the impregnated modified blended fiber to obtain an intermediate layer for a copper clad laminate.

[0063] In some optional embodiments, the drying temperature may be 140° C. to 350° C., which is specifically set according to the resin used in the impregnation liquid.

[0064] Correspondingly, the present invention also provides a copper clad laminate comprising copper foil and the above-mentioned intermediate layer.

[0065] In some optional embodiments, the dielectric constant of the copper clad laminate is 2.6 to 3.0.

[0066] In some optional embodiments, the dielectric loss of the copper clad laminate does not exceed 0.0016.

[0067] In some optional embodiments, the expansion coefficient of the copper clad laminate in the Z-axis does not exceed 25.

[0068] In some optional embodiments, the Tg of the copper clad laminate is not less than 220°C.

[0069] In some optional embodiments, the peel strength of the copper clad laminate is not less than 1.20.

[0070] The copper clad laminate has low dielectric loss and expansion coefficient, good peel strength, heat resistance and flexibility, etc.

[0071] Accordingly, the present invention also provides a method for preparing the above-mentioned copper clad laminate, which may include, for example, laminating an intermediate layer with a copper foil. In some optional embodiments, the lamination pressure may be 25 MPa to 35 MPa, such as 25 MPa, 28 MPa, 30 MPa, 32 MPa, or 35 MPa, or other values ​​within the range of 25 MPa to 35 MPa. The lamination temperature may be 180°C to 220°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, or 220°C, or other values ​​within the range of 180°C to 220°C. The lamination time may be 1 hour to 4 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours, or other values ​​within the range of 1 hour to 4 hours.

[0072] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0073] Example 1

[0074] This embodiment provides a copper clad laminate, the preparation method of which includes the following steps:

[0075] S1: Orthogonally weave PBO fiber as the warp fiber and glass fiber as the weft fiber, and stack the single layers obtained by orthogonal weaving along the Z axis (the thickness direction of the copper clad laminate) to obtain a blended fiber.

[0076] The mass ratio of the PBO fiber to the glass fiber is 30:70. The glass fiber has a dielectric loss of 0.034 and a dielectric constant of 6.8. The warp density is 60 strands / inch, the weft density is 80 strands / inch, and the warp pretension is 15N.

[0077] S2: Plasma-treating the blended fibers to obtain modified blended fibers.

[0078] The power of the plasma treatment was 300 W, the time was 5 min, and the treatment atmosphere was argon atmosphere.

[0079] S3: impregnating the modified blended fiber in an impregnation solution containing resin.

[0080] The impregnation liquid contains resin and filler, wherein the content of the resin is 85wt% and the content of the filler is 15wt%. The resin is PPO resin and the filler is nano-silicon dioxide (expansion coefficient is 8ppm). The viscosity of the impregnation liquid is 2000cps.

[0081] S4: Drying the impregnated modified blended fiber to obtain an intermediate layer (prepreg).

[0082] The drying temperature is 150°C and the drying time is 2 minutes.

[0083] S5: Laminating the prepreg with copper foil.

[0084] The lamination pressure was 30 MPa, the temperature was 200°C, and the time was 2 h.

[0085] Example 2

[0086] This embodiment provides a copper clad laminate, the preparation method of which includes the following steps:

[0087] S1: PBO fiber is used as the warp fiber and glass fiber is used as the weft fiber for orthogonal weaving to obtain a blended fiber.

[0088] The mass ratio of the PBO fiber to the glass fiber is 10:90. The glass fiber has a dielectric loss of 0.034 and a dielectric constant of 6.8. The warp density is 80 strands / inch, the weft density is 60 strands / inch, and the warp pretension is 10N.

[0089] S2: Plasma-treating the blended fibers to obtain modified blended fibers.

[0090] The power of the plasma treatment was 50 W, the time was 120 min, and the treatment atmosphere was argon atmosphere.

[0091] S3: impregnating the modified blended fiber in an impregnation solution containing resin.

[0092] The impregnation liquid contains resin and filler, wherein the content of the resin is 80wt% and the content of the filler is 20wt%. The resin is BMI resin and the filler is nano boron nitride (expansion coefficient is 8ppm). The viscosity of the impregnation liquid is 2500cps.

[0093] S4: Drying the impregnated modified blended fiber to obtain an intermediate layer (prepreg).

[0094] The drying temperature is 160°C and the drying time is 2 minutes.

[0095] S5: Laminating the prepreg with copper foil.

[0096] The lamination pressure was 25 MPa, the temperature was 220°C, and the time was 4 h.

[0097] Example 3

[0098] This embodiment provides a copper clad laminate, the preparation method of which includes the following steps:

[0099] S1: PBO fiber is used as the warp fiber and glass fiber is used as the weft fiber for orthogonal weaving to obtain a blended fiber.

[0100] The mass ratio of the PBO fiber to the glass fiber is 60:40. The glass fiber has a dielectric loss of 0.034 and a dielectric constant of 6.8. The warp density is 70 strands / inch, the weft density is 70 strands / inch, and the warp pretension is 15N.

[0101] S2: Plasma-treating the blended fibers to obtain modified blended fibers.

[0102] The power of the plasma treatment was 600 W, the time was 1 min, and the treatment atmosphere was argon atmosphere.

[0103] S3: impregnating the modified blended fiber in an impregnation solution containing resin.

[0104] The impregnation liquid contains resin and filler, wherein the content of the resin is 70wt% and the content of the filler is 30wt%. The resin is BT resin and the filler is nano-aluminum hydroxide (expansion coefficient is 10ppm). The viscosity of the impregnation liquid is 1800cps.

[0105] S4: Drying the impregnated modified blended fiber to obtain an intermediate layer (prepreg).

[0106] The drying temperature is 170°C and the drying time is 2 minutes.

[0107] S5: Laminating the prepreg with copper foil.

[0108] The lamination pressure was 35 MPa, the temperature was 180°C, and the time was 1 h.

[0109] Example 4

[0110] The difference between this embodiment and embodiment 1 is that: in S1, glass fiber is used as the warp fiber and PBO fiber is used as the weft fiber for orthogonal weaving, and the single layer obtained by orthogonal weaving is stacked along the Z axis (the thickness direction of the copper clad laminate) to obtain a blended fiber.

[0111] Example 5

[0112] The difference between this embodiment and embodiment 1 is that in S3, the filler is a mixture of nano-silicon dioxide and boron nitride (mass ratio is 1:1).

[0113] Example 6

[0114] The difference between this embodiment and embodiment 1 is that in S2, the blended fiber is treated with a silane coupling agent to obtain a modified blended fiber.

[0115] The silane coupling agent treatment includes: preparing a 5 wt% silane coupling agent aqueous solution of KH550 coupling agent and water, immersing the blended fiber in the silane coupling agent aqueous solution at a mass ratio of 0.5:100 and maintaining it for 30 minutes, and then taking out the blended fiber and drying it in an oven at 80° C. for 1 hour.

[0116] Example 7

[0117] The difference between this embodiment and embodiment 1 is that: S2 is to irradiate the blended fiber to obtain modified blended fiber.

[0118] The irradiation treatment uses gamma ray irradiation, with a total irradiation energy of 30 kGy, a specific irradiation time of 3 hours, and an irradiation energy of 10 kGy per hour.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is that in S1, alkali-free glass fiber (E glass fiber) is used instead of PBO fiber.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 is that in S1, the mass ratio of PBO fiber to glass fiber is 5:95.

[0123] Comparative Example 3

[0124] The difference between this comparative example and Example 1 is that in S1, the mass ratio of PBO fiber to glass fiber is 70:30.

[0125] Comparative Example 4

[0126] The difference between this comparative example and Example 1 is that in S1, the warp pretension is 5N.

[0127] Comparative Example 5

[0128] The difference between this comparative example and Example 1 is that in S1, the warp pretension is 20N.

[0129] Comparative Example 6

[0130] The difference between this comparative example and Example 1 is that the blended fibers are not modified and are directly impregnated in the resin-containing impregnation liquid, that is, S3 is directly performed after S1.

[0131] Comparative Example 7

[0132] The difference between this comparative example and Example 1 is that in S3, the impregnation liquid does not contain filler.

[0133] Comparative Example 8

[0134] The difference between this comparative example and Example 1 is that in S3, the content of the filler is 10 wt%.

[0135] Test example

[0136] The copper clad laminates obtained in Examples 1 to 7 and Comparative Examples 1 to 8 were subjected to performance tests, and a commercially available PTFE (polytetrafluoroethylene) copper clad laminate was used as a control. The results are shown in Tables 1 and 2. k Refers to the dielectric constant (under 10GHz conditions), the test standard refers to IPC-TM-650 2.5.5.5C; D f Refers to dielectric loss, tested according to IPC-TM-6502.5.5.5C:1998; CTE refers to the coefficient of thermal expansion along the Z axis, measured in ppm / °C, tested according to IPC-TM-650 2.4.24C:1994; Tg refers to the glass transition temperature, measured in °C, tested according to GB / T 40396-2021.

[0137] Table 1 Test results

[0138] <![CDATA[D k ]]> <![CDATA[D f ]]> CTE Tg Peel strength Example 1 2.8 0.0013 17 220 1.2 Comparative Example 1 3.7 0.0056 60 200 0.6 comparison 3.0 ＜0.0010 50 / 0.8

[0139] Table 2 Test results

[0140]

[0141]

[0142] It can be seen from Table 1 that the copper clad laminate prepared in Example 1 of the present invention is better than that in Comparative Example 1 and commercially available PTFE copper clad laminate in D k , CTE, and peel strength all have significantly better performance effects, and the copper clad laminate prepared in Example 1 also has significantly lower dielectric loss than the copper clad laminate prepared in Comparative Example 1. This shows that the present invention can effectively improve the dielectric properties, heat resistance, and strength properties of the copper clad laminate by preparing PBO fiber and glass fiber into an intermediate layer according to a specific method and then laminating it with copper foil to prepare the copper clad laminate. Moreover, the copper clad laminate provided in Example 1 not only has a lower dielectric constant than the control copper clad laminate, but also has a significantly lower expansion coefficient in the Z axis. In addition, the glass strength is higher.

[0143] Combining Table 1 and Table 2, it can be seen that the copper clad laminates prepared in Examples 2 to 7 are also better than those in Comparative Example 1 and the commercially available PTFE copper clad laminates in D k , CTE and peel strength have significantly better performance effects. This shows that the intermediate layer prepared by the specific material and specific method provided by the present invention is conducive to obtaining a copper clad laminate with better dielectric properties, heat resistance and strength properties than the existing technology.

[0144] From the comparison between Example 1 and Comparative Example 2, it can be seen that if the amount of PBO fiber used is too small, the dielectric constant and dielectric loss of the copper clad laminate will increase significantly, and the expansion coefficient of the Z axis will also increase significantly; from the comparison between Example 1 and Comparative Example 3, it can be seen that when the amount of PBO fiber used is too much, the expansion coefficient of the Z axis will also increase, and the peel strength of the copper clad laminate will also decrease.

[0145] From the comparison between Example 1 and Comparative Example 4, it can be seen that when the warp pre-tension is too small during the preparation of the intermediate layer, the dielectric loss of the copper clad laminate will increase, the expansion coefficient of the Z axis will increase, and the peel strength will decrease; from the comparison between Example 1 and Comparative Example 5, it can be seen that when the warp pre-tension is too large during the preparation of the intermediate layer, the dielectric loss of the copper clad laminate will increase and the peel strength will decrease, and in addition, Tg will also decrease.

[0146] From the comparison between Example 1 and Comparative Example 6, it can be seen that if the blended fibers are not modified, the expansion coefficient of the copper clad laminate along the Z axis will increase and the peel strength will decrease.

[0147] From the comparison between Example 1 and Comparative Example 7, it can be seen that if the impregnation liquid does not contain fillers, the dielectric loss of the copper clad laminate will increase, the expansion coefficient of the Z axis will increase, and the peel strength will decrease.

[0148] From the comparison between Example 1 and Comparative Example 8, it can be seen that if the filler content is too low, the dielectric loss of the copper clad laminate will increase, the expansion coefficient of the Z axis will increase, and the peel strength will decrease.

[0149] Therefore, in this application, the mass ratio of PBO fiber to glass fiber, the warp pretension during weaving, the modification of the blended fiber, and the filler content in the impregnation solution will all have a direct impact on the final performance of the copper clad laminate and cannot be changed arbitrarily.

[0150] In summary, the preparation method of the copper clad laminate provided by the present invention is simple and easy to operate. The method can prepare a copper clad laminate with a low dielectric constant, dielectric loss, expansion coefficient and better peel strength, and the copper clad laminate also has good heat resistance and flexibility.

[0151] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing an intermediate layer for a copper clad laminate, characterized in that: The following steps are involved: Orthogonally weaving PBO fibers and glass fibers to obtain blended fibers; wherein the mass ratio of the PBO fibers to the glass fibers is 10:90 to 60:40; Modifying the blended fiber to obtain modified blended fiber; impregnating the modified blended fiber in an impregnation solution containing resin; The impregnated modified blended fiber is dried to obtain an intermediate layer for a copper clad laminate.

2. The preparation method according to claim 1, characterized in that Orthogonal weaving uses a method of vertical weaving in the warp and weft directions, where the warp density is 60 to 80 strands / inch and the weft density is 60 to 80 strands / inch. Preferably, the warp pre-tension is 10N to 15N.

3. The preparation method according to claim 1, characterized in that The dielectric loss of the glass fiber does not exceed 0.0035, and the dielectric constant does not exceed 6.

8.

4. The preparation method according to claim 1, characterized in that The modification treatment includes at least one of plasma treatment, silane coupling agent treatment and radiation treatment.

5. The preparation method according to claim 4, characterized in that When the modification treatment is plasma treatment, the power of the plasma treatment is 50W to 600W, the treatment time is 1min to 120min, and the treatment atmosphere is an inert atmosphere; When the modified silane coupling agent is used, the silane coupling agent includes at least one of KH550, KH792 and KH560; When the modification treatment is irradiation treatment, the irradiation energy is 20 kGy to 270 kGy.

6. The preparation method according to claim 1, characterized in that The resin content in the impregnation liquid is 35% to 75%; Preferably, the resin includes at least one of PPO resin, hydrocarbon resin, BMI resin and BT resin; Preferably, the viscosity of the impregnation liquid does not exceed 10,000 cps.

7. The preparation method according to claim 6, characterized in that The impregnation liquid further contains a filler; Preferably, the amount of filler contained in the impregnation liquid is not less than 15 wt%; Preferably, the filler comprises at least one of silicon dioxide, aluminum hydroxide, boehmite and boron nitride; Preferably, the expansion coefficient of the filler does not exceed 40 ppm.

8. An intermediate layer for a copper clad laminate, characterized in that: The intermediate layer is prepared by the method according to any one of claims 1 to 7.

9. A copper clad laminate, characterized in that: The copper clad laminate comprises copper foil and the intermediate layer according to claim 8; Preferably, the copper clad laminate has at least one of the following characteristics: Feature 1: The dielectric constant of the copper clad laminate is 2.6 to 3.0; Feature 2: The dielectric loss of the copper clad laminate does not exceed 0.0016; Feature 3: The expansion coefficient of the copper clad laminate in the Z axis does not exceed 25; Feature 4: The Tg of the copper clad laminate is not less than 220°C; Feature 5: The peel strength of the copper clad laminate is not less than 1.

20.

10. A method for preparing a copper clad laminate according to claim 9, characterized in that: include: laminating the intermediate layer with copper foil; Preferably, the lamination pressure is 25 MPa to 35 MPa, the temperature is 180° C. to 220° C., and the lamination time is 0.5 h to 8 h.

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