Low-dielectric waterborne epoxy-PTFE composite layered structure material as well as preparation method and application thereof

Abstract

The invention discloses a low-dielectric waterborne epoxy-PTFE (polytetrafluoroethylene) composite layered structure material as well as a preparation method and application thereof. The low-dielectric waterborne epoxy-PTFE composite layered structure material is formed by mainly taking glass fabric as a base material and sequentially covering the surface of the base material with an epoxy resin layer and a polytetrafluoroethylene isolating layer, the epoxy resin layer mainly comprises the following raw materials in parts by weight: 100 parts of modified waterborne epoxy emulsion; the molar ratio of the curing agent active hydrogen equivalent to epoxy groups in the modified waterborne epoxy curing agent emulsion is (0.9: 1)-(1.1: 1); 10 to 50 parts of filler; 25 to 35 parts of a flame retardant; and 1-5 parts of a silane coupling agent. According to the invention, the epoxy resin is modified by adopting the PTFE emulsion, and a double-layer structure is prepared, so that the dielectric constant and the dielectric loss can be effectively reduced. The dielectric constant (Dk at 10GHz) of the obtained product is 2.1-2.4, and the dielectric loss (Df at 10GHz) is less than or equal to 0.0015; secondly, the interface bonding strength of the PTFE layer and the epoxy layer is greater than or equal to 0.8 MPa, and the peel strength is not obviously reduced; a step-by-step coating process is also adopted, so that direct mixing of two phases is avoided, and the problem of compatibility is solved.

Description

Technical Field

[0001] The present invention relates to a low-dielectric waterborne epoxy-PTFE composite layered structure material, a preparation method and an application thereof, and belongs to the technical field of waterborne epoxy materials. Background Art

[0002] In the existing copper clad laminates, epoxy resin and PTFE are mostly blended and modified to reduce the dielectric properties. However, the compatibility between PTFE and epoxy resin is poor, which easily leads to interfacial defects, and the traditional blending process is difficult to avoid the problem of uneven dispersion of PTFE.

[0003] Although directly adding PTFE emulsion can improve the dispersibility, excessive addition will reduce the crosslinking density of epoxy resin and lead to a decline in mechanical properties.

[0004] In the prior art, most epoxy resin curing agents are solvent-based or powdery, and have poor compatibility with waterborne systems, which affects the process stability.

[0005] In addition, in the prior art, there are also related studies on using waterborne epoxy resin to make layered materials, but their thickness is large and the effect of reducing dielectric properties is poor. Summary of the Invention

[0006] Object of the Invention: In order to solve the above technical problems, the present invention provides a low-dielectric waterborne epoxy-PTFE composite layered structure material, a preparation method and an application thereof. The present invention forms a dense PTFE isolation layer on the surface of the epoxy layer through a step-by-step coating process, which not only reduces the dielectric loss but also avoids interfacial defects between the two phases; at the same time, a waterborne curing agent emulsion is used to improve the system compatibility, and both environmental protection and industrial feasibility are achieved.

[0007] Technical Solution: In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A low-dielectric waterborne epoxy-PTFE composite layered structure material, which is mainly formed by using a glass fiber cloth as a base material and sequentially covering an epoxy resin layer and a polytetrafluoroethylene isolation layer on its surface;

[0009] The epoxy resin layer mainly comprises the following raw materials in parts by weight:

[0010] 100 parts of modified waterborne epoxy emulsion;

[0011] A waterborne epoxy curing agent emulsion, wherein the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy group in the modified waterborne epoxy emulsion is 0.9:1 to 1.1:1;

[0012] 10-50 parts of filler;

[0013] 25-35 parts of flame retardant;

[0014] 1-5 parts of silane coupling agent.

[0015] As a specific embodiment, the solid content of the modified waterborne epoxy emulsion is 40-60%, and it contains carboxyl or hydroxyl functional groups.

[0016] As a specific embodiment, the waterborne epoxy curing agent emulsion is selected from one or more of amine-based, phenolic resin-based or anhydride-based curing agents; the particle size of the waterborne epoxy curing agent emulsion is 100-500 nm.

[0017] As a specific embodiment, the filler is selected from one or a combination of several of silica and boron nitride, and the particle size is 0.5-10 μm; the flame retardant is selected from aluminum diethylphosphinate; the silane coupling agent is selected from one or a combination of several of γ-aminopropyltriethoxysilane KH-550 and γ-glycidoxypropyltrimethoxysilane KH-560.

[0018] As a specific embodiment, the raw material of the polytetrafluoroethylene isolation layer is polytetrafluoroethylene PTFE emulsion, and its coating amount is 5-30 g / m 2 , and the thickness is 0.5-5 μm.

[0019] Furthermore, the solid content of the polytetrafluoroethylene PTFE emulsion is 20-50%, and the particle size ≤500 nm.

[0020] The present invention also provides a preparation method of the low-dielectric waterborne epoxy-PTFE composite layered structure material described above, including the following steps:

[0021] (1) Preparation of the epoxy resin layer: Mix the modified waterborne epoxy emulsion with the waterborne epoxy curing agent emulsion, add the filler, flame retardant, and silane coupling agent, impregnate the fiberglass cloth, and then dry it to a semi-cured state;

[0022] (2) Coating of the polytetrafluoroethylene isolation layer: Spray or roll-coat the polytetrafluoroethylene PTFE emulsion on the surface of the semi-cured epoxy resin layer, and dry it to form a dense isolation layer;

[0023] As a specific embodiment:

[0024] In step (1), the drying to a semi-cured state is carried out at 80-120 °C to a semi-cured state;

[0025] In step (2), the drying to form a dense isolation layer is carried out at 120-150 °C to form a dense isolation layer;

[0026] The conditions for hot pressing and forming are: hot pressing and curing at 180-220 °C and 5-15 MPa.

[0027] Finally, the present invention provides the application of the low-dielectric waterborne epoxy-PTFE composite laminated structure material in the preparation of copper clad laminates or prepregs.

[0028] As a specific implementation, the application includes covering copper foils on the upper and lower surfaces of the composite laminated structure material during the lamination process and hot pressing and molding to prepare copper clad laminates.

[0029] Furthermore, the conditions for the hot pressing and molding are: hot pressing and curing at 180 - 220 °C and 5 - 15 MPa.

[0030] Technical effects: Compared with the prior art, the present invention modifies epoxy resin with PTFE emulsion and forms a bilayer structure, which can effectively reduce the dielectric constant and dielectric loss. The dielectric constant (Dk@10GHz) of the obtained product is between 2.1 - 2.4, and the dielectric loss (Df@10GHz) ≤ 0.0015. Secondly, the interfacial bonding strength between the PTFE layer and the epoxy layer ≥ 0.8 MPa, and the peel strength does not decrease significantly; the present invention also adopts a step-by-step coating process to avoid direct mixing of the two phases and solve the compatibility problem.

[0031] In addition, compared with the existing multi-layer structures, the two-layer structure in the present invention can form a thinner layer structure. At the same time, since the low-dielectric PTFE in direct contact with the signal transmission layer (i.e., copper foil) is on the outermost layer, it can bring higher low-dielectric and low-loss benefits. Detailed implementation manners

[0032] The following further clarifies the present invention in combination with specific examples. [[ID=z19]]

[0033] Unless otherwise defined herein, the scientific and technical terms used in this application shall have the meanings commonly understood by those of ordinary skill in the art.

[0034] 1) The raw materials of the following examples and comparative examples are specifically as follows:

[0035] Carboxyl-modified waterborne epoxy emulsion (solid content 50%, purchased from Handai Chemical);

[0036] Phenolic resin curing agent emulsion (solid content 40%, the curing agent powder is purchased from Shandong Shengquan, emulsified by a modified polyether-type epoxy resin active emulsifier (JT-801, purchased from Foshan Juntu New Materials Co., Ltd.), particle size 100 - 500 nm)

[0037] The filler is spherical silica (5 μm, purchased from Jiangsu Lianrui);

[0038] The flame retardant is aluminum diethylphosphinate (purchased from Qingdao Opurui);

[0039] The silane coupling agent is KH-560 (purchased from Nanjing Shuguang)

[0040] Glass fiber cloth (7628, purchased from Kingboard Chemical)

[0041] PTFE emulsion (solid content 30%, purchased from Juhua, JF-DCD, diluted with deionized water to the required solid content before use, particle size ≤ 500 nm).

[0042] 2) The product performance test methods for the following examples and comparative examples are as follows:

[0043] The peel strength was tested according to the standard of

IPC-TM650 2.4.8

[0044] Dk and Df: Tested by the SPDR (split post dielectric resonator) method, referring to the standard of

IPC-TM650 2.5.5.13

[0045] Example 1

[0046] (1) Epoxy layer: 100 parts of carboxyl-modified waterborne epoxy emulsion (solid content 50%), 30 parts of phenolic resin curing agent emulsion (solid content 40%, and the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy group in the modified waterborne epoxy emulsion is 1:1), 25 parts of spherical silica (5 μm), 30 parts of aluminum diethyl phosphinate, 3 parts of KH-560, impregnated the glass fiber cloth and dried it at 100 °C to the semi-cured state;

[0047] (2) PTFE layer: Sprayed PTFE emulsion (solid content 30%), coating amount 15 g / m 2 , dried at 140 °C to form a dense isolation layer with a thickness of 3 μm;

[0048] (3) Hot pressing: Covered one layer of 35 μm electronic copper foil on each of the upper and lower surfaces of the laminated material, pressed at 200 °C / 10 MPa for 1 hour to make a copper clad laminate.

[0049] Test results: Dk = 2.2, Df = 0.0013, peel strength 1.5 N / mm.

[0050] Example 2

[0051] (1) Epoxy layer: 100 parts of carboxyl-modified waterborne epoxy emulsion (solid content 50%), 30 parts of phenolic resin curing agent emulsion (solid content 40%, and the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy group in the modified waterborne epoxy emulsion is 1:1), 25 parts of spherical silica (5 μm), 30 parts of aluminum diethyl phosphinate, 3 parts of KH-560, impregnated the glass fiber cloth and dried it at 100 °C to the semi-cured state;

[0052] (2) PTFE layer: Spray PTFE emulsion (solid content 30%), coating amount 5 g / m 2 , and dry at 140 °C to form a dense isolation layer with a thickness of 3 μm;

[0053] (3) Hot pressing: Cover each of the upper and lower surfaces of the layered material with a 35-μm electrolytic copper foil, and press at 200 °C / 10 MPa for 1 hour to make a copper-clad laminate.

[0054] Test results: Dk = 2.1, Df = 0.0012, peel strength 1.7 N / mm.

[0055] Example 3

[0056] (1) Epoxy layer: 100 parts of carboxyl-modified waterborne epoxy emulsion (solid content 50%), 30 parts of phenolic resin curing agent emulsion (solid content 40%, where the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy group in the modified waterborne epoxy emulsion is 1:1), 25 parts of spherical silica (5 μm), 30 parts of aluminum diethylphosphinate, 3 parts of KH-560. After impregnating the fiberglass cloth, dry at 100 °C to a semi-cured state;

[0057] (2) PTFE layer: Spray PTFE emulsion (solid content 30%), coating amount 20 g / m 2 , and dry at 140 °C to form a dense isolation layer with a thickness of 3 μm;

[0058] (3) Hot pressing: Cover each of the upper and lower surfaces of the layered material with a 35-μm electrolytic copper foil, and press at 200 °C / 10 MPa for 1 hour to make a copper-clad laminate.

[0059] Test results: Dk = 2.4, Df = 0.0015, peel strength 1.5 N / mm.

[0060] Example 4

[0061] (1) Epoxy layer: 100 parts of carboxyl-modified waterborne epoxy emulsion (solid content 50%), 25 parts of phenolic resin curing agent emulsion (solid content 40%, where the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy group in the modified waterborne epoxy emulsion is 1:1), 25 parts of spherical silica (5 μm), 30 parts of aluminum diethylphosphinate, 3 parts of KH-560. After impregnating the fiberglass cloth, dry at 100 °C to a semi-cured state;

[0062] (2) PTFE layer: Spray PTFE emulsion (solid content 30%), coating amount 30 g / m 2 , and dry at 140 °C to form a dense isolation layer with a thickness of 3 μm;

[0063] (3) Hot pressing: Cover each of the upper and lower surfaces of the layered material with a 35-μm electrolytic copper foil, and press at 200 °C / 10 MPa for 1 hour to make a copper-clad laminate.

[0064] Test results: Dk = 2.2, Df = 0.0013, peel strength 1.4 N / mm.

[0065] Comparative example (PTFE and epoxy blend):

[0066] (1) Epoxy / PTFE mixed layer: 100 parts of carboxyl-modified waterborne epoxy emulsion (solid content 50%), 30 parts of phenolic resin curing agent emulsion (solid content 40%, where the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy groups in the modified waterborne epoxy emulsion is 1:1), 20 parts of PTFE emulsion (solid content 30%), 25 parts of spherical silica (5 μm), 30 parts of aluminum diethylphosphinate, 3 parts of KH-560, impregnated on fiberglass cloth and dried at 100 °C;

[0067] (2) Hot pressing: Cover each surface of the fiberglass cloth with a 35-μm electrolytic copper foil, press at 200 °C / 10 MPa for 1 hour to make a copper-clad laminate.

[0068] Test results: Dk = 3.5, Df = 0.0045, peel strength 0.9 N / mm, proving the dual advantages of the layered structure in dielectric and mechanical properties.

[0069] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A low-dielectric waterborne epoxy-PTFE composite laminated structure material, characterized in that, The low-dielectric waterborne epoxy-PTFE composite laminated structure material is mainly formed by using a glass fiber cloth as a base material, and sequentially covering an epoxy resin layer and a polytetrafluoroethylene isolation layer on its surface; The epoxy resin layer mainly comprises the following raw materials in parts by weight: 100 parts of a modified waterborne epoxy emulsion; A waterborne epoxy curing agent emulsion, wherein the molar ratio of the active hydrogen equivalent of the curing agent to the epoxy groups in the modified waterborne epoxy emulsion is 0.9:1 to 1.1:1; 10 - 50 parts of a filler; 25 - 35 parts of a flame retardant; 1 - 5 parts of a silane coupling agent.

2. The low-dielectric waterborne epoxy-PTFE composite laminated structural material according to claim 1, wherein The solid content of the modified waterborne epoxy emulsion is 40 - 60%, and it contains carboxyl or hydroxyl functional groups.

3. The low-dielectric waterborne epoxy-PTFE composite laminated structure material according to claim 1, wherein The waterborne epoxy curing agent emulsion is selected from one or more of amine-based, phenolic resin-based, or anhydride-based curing agents; the particle size of the waterborne epoxy curing agent emulsion is 100 - 500 nm.

4. The low-dielectric waterborne epoxy-PTFE composite laminated structure material according to claim 1, characterized in that, The filler is selected from one or more combinations of silica and boron nitride, and the particle size is 0.5 - 10 μm; the flame retardant is selected from aluminum diethylphosphinate; the silane coupling agent is selected from one or more combinations of γ-aminopropyltriethoxysilane KH-550 and γ-glycidoxypropyltrimethoxysilane KH-560.

5. The low-dielectric waterborne epoxy-PTFE composite laminated structural material according to claim 1, characterized in that The raw material of the polytetrafluoroethylene isolation layer is polytetrafluoroethylene PTFE emulsion, and its coating amount is 5-30 g / m 2 , and the thickness is 0.5-5 μm.

6. The low-dielectric waterborne epoxy-PTFE composite laminated structure material according to claim 5, wherein The solid content of the polytetrafluoroethylene (PTFE) emulsion is 20 - 50%, and the particle size ≤ 500 nm.

7. The preparation method of the low-dielectric waterborne epoxy-PTFE composite layered structure material according to any one of claims 1-6, characterized in that, It includes the following steps: (1) Preparation of the epoxy resin layer: Mix the modified waterborne epoxy emulsion with the waterborne epoxy curing agent emulsion, add the filler, flame retardant, and silane coupling agent, impregnate the glass fiber cloth, and then dry it to a semi-cured state; (2) Coating of the polytetrafluoroethylene isolation layer: Spray or roll-coat the polytetrafluoroethylene (PTFE) emulsion on the surface of the semi-cured epoxy resin layer, and dry it to form a dense isolation layer.

8. The preparation method of the low-dielectric waterborne epoxy-PTFE composite laminated structure material according to claim 7, wherein: In step (1), the drying to a semi-cured state is drying to a semi-cured state at 80 - 120 °C; In step (2), the drying to form a dense isolation layer is drying to form a dense isolation layer at 120 - 150 °C.

9. The application of the low-dielectric waterborne epoxy-PTFE composite laminated structure material according to any one of claims 1 - 6 in the preparation of a copper-clad laminate or a prepreg.

10. The application according to claim 9, wherein The application includes covering copper foils on the upper and lower surfaces of the composite laminated structure material during the lamination process, and hot-pressing to form a copper-clad laminate.