Preparation method of adhesive-free single-sided flexible copper-clad plate with simple and convenient process

Abstract

The invention discloses a preparation method of a non-adhesive single-sided flexible copper-clad plate, which is simple and convenient in process, and comprises the following steps: sequentially overlapping a release layer, at least one polyimide composite film, a copper foil layer and a protective layer together, and placing in a high-temperature roller pressing machine for high-temperature roller hot-pressing treatment to obtain the non-adhesive single-sided flexible copper-clad plate. The adhesive-free single-sided flexible copper-clad plate with the release layer and the protective layer is obtained; the release layer is a thermosetting polyimide film; the polyimide composite film is a polyimide film of which the two surfaces are coated with thermoplastic medium layers or thermoplastic polyimide layers; wherein the conditions of the high-temperature roller hot-pressing treatment are as follows: the temperature of a hot-pressing roller in contact with the protective layer is 330-360 DEG C, the temperature of a hot-pressing roller in contact with the release layer is 200-280 DEG C, the hot-pressing speed is 1.0-3.0 m / min, and the hot-pressing pressure is 14-20 Kg. According to the preparation method disclosed by the invention, the technological process of the traditional adhesive-free single-sided flexible copper-clad plate is simplified, the production efficiency is improved, and large-scale continuous production can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic materials, and in particular relates to a method for preparing a glue-free single-sided flexible copper-clad laminate with simple process. Background Art

[0002] Flexible copper clad laminate (FCCL) is light, thin, highly heat-resistant and flexible. Therefore, FPC with flexible copper clad laminate as substrate material is widely used in electronic equipment, consumer electronics, and electronic communication products. With the advancement of science and technology, the miniaturization and high-precision requirements of electronic products are getting higher and higher. In addition to the electrical connection, insulation, and mechanical support functions of general copper clad laminates, polyimide flexible copper clad laminates can also be bent repeatedly. Flexible printed circuit boards made of flexible copper clad laminates can make wiring more reasonable, save installation space, and meet the needs of electronic products that are becoming increasingly thinner and shorter.

[0003] The conventional method for preparing adhesive-free single-sided polyimide flexible copper clad laminates has a complex production process (including adhesive preparation, coating, baking, etc.), and the prepared adhesive-free single-sided polyimide flexible copper clad laminates have poor stability and low production efficiency, which is difficult to meet the needs of actual production and application. Therefore, it is necessary to invent a simple production process for adhesive-free single-sided polyimide flexible copper clad laminates to improve the production efficiency of single-sided adhesive-free polyimide flexible copper clad laminates. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a non-adhesive single-sided polyimide flexible copper-clad laminate with a simple process in view of the deficiencies of the prior art. The preparation method of the present invention simplifies the process flow of the conventional non-adhesive single-sided flexible copper-clad laminate, improves production efficiency, and can realize large-scale continuous production. By controlling the tension under hot pressing conditions, the appearance defects of the conventional non-adhesive single-sided polyimide flexible copper-clad laminate, such as wrinkles and scratches, can also be reduced.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention discloses a method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process, comprising the following steps:

[0007] The release layer, at least one layer of polyimide composite film, copper foil layer and protective layer are sequentially stacked together, and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment to obtain a non-adhesive single-sided flexible copper clad laminate with a release layer and a protective layer;

[0008] The release layer is a thermosetting polyimide (PI) film;

[0009] The polyimide composite film is a polyimide film with thermoplastic dielectric layers or thermoplastic polyimide (TPI) layers on both sides;

[0010] The conditions for high temperature roller hot pressing treatment are:

[0011] The temperature of the hot pressing roller contacting the protective layer is 330-360° C., the temperature of the hot pressing roller contacting the release layer is 200-280° C., the hot pressing speed is 1.0-3.0 m / min, and the hot pressing pressure is 14-20 Kg.

[0012] In the present invention, the thickness of the polyimide composite film is 25-100 μm.

[0013] In the present invention, the release layer has a thickness of 50 to 125 μm and a width of 10 to 20 mm wider than the polyimide composite film.

[0014] In the present invention, the copper foil layer has a copper tooth Rz value of 0.7 to 2.8 μm, a copper foil layer thickness of 9 to 35 μm, and a width of 10 to 20 mm wider than that of the polyimide composite film.

[0015] In the present invention, the thermoplastic medium layer is made of a thermoplastic medium, and the Tg temperature of the thermoplastic medium is 210-300°C.

[0016] In the present invention, the protective layer is a layer of copper foil or a thermosetting polyimide film.

[0017] The method for preparing the adhesive-free single-sided flexible copper clad laminate with simple process in the present invention also includes rolling up the prepared adhesive-free single-sided flexible copper clad laminate with a release layer and a protective layer, and the rolling end independently rolls up the release layer, the adhesive-free single-sided flexible copper clad laminate, and the protective layer during rolling up.

[0018] The adhesive-free single-sided flexible copper-clad laminate prepared by the invention has a peeling strength of ≥1.0N / mm, a soldering temperature resistance of greater than 300°C, and a warpage of <1.5cm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses a copper foil layer, a polyimide composite film (containing thermoplastic polyimide or thermoplastic dielectric layers on both sides) and a release layer (thermosetting polyimide film) for lamination, and obtains a non-adhesive single-sided polyimide flexible copper-clad laminate by means of high-temperature roller hot pressing. This preparation method simplifies the process flow of traditional non-adhesive single-sided polyimide flexible copper-clad laminates, reduces the process deficiencies of the prior art, improves production efficiency, and can achieve large-scale continuous production. By controlling the tension under hot pressing conditions, the appearance defects of the traditional non-adhesive single-sided polyimide flexible copper-clad laminate, such as wrinkles and scratches, can be reduced. A protective layer is added above the copper foil layer to protect the copper foil layer, further enhancing the anti-warping performance of the non-adhesive single-sided polyimide flexible copper-clad laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the laminated pressing structure in Examples 1-3 of the present invention;

[0022] Figure 2 is a schematic diagram of the laminated pressing structure in Embodiment 4-5 of the present invention;

[0023] Figure 3 Schematic diagram of the structure of the adhesive-free single-sided polyimide flexible copper-clad laminate prepared in Examples 1-3 of the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the adhesive-free single-sided polyimide flexible copper clad laminate prepared in Example 4-5 of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0026] Example

[0027] The polyimide composite film in the embodiment of the present invention is a polyimide film containing a thermoplastic dielectric layer or a thermoplastic polyimide (TPI) layer on both sides, purchased from DuPont, KANEKA, and UBE, wherein the Tg temperature of the thermoplastic dielectric layer is 210-300°C. The copper foil layer is a low-roughness electrolytic or rolled copper foil sold on the market. In this embodiment, the preferred copper foil layer is Mitsui electrolytic copper foil, the copper tooth Rz value of the copper foil layer is 1.1 μm, and the thickness of the copper foil layer is 12 μm; the release layer and the protective layer both use a thermosetting polyimide film with a film thickness of 50 μm.

[0028] Example 1

[0029] like Figure 1 As shown, in this embodiment 1, a single-sided adhesive-free polyimide flexible copper-clad laminate is prepared into a laminated structure, which includes a release layer 10, a 25 μm polyimide composite film 20, a copper foil layer 30, and a protective layer 40 from top to bottom;

[0030] A five-axis high-temperature press is used for roll-to-roll high-temperature hot pressing, and the press stacking structure is shown in Table 1:

[0031] Table 1 25μm single-sided adhesive-free polyimide flexible copper clad laminate high temperature hot pressing lamination

[0032] Serial number Material Tier 1 Release layer (thermosetting polyimide film) Tier 2 25μm polyimide composite film Tier 3 12μm copper foil Layer 4 Protective layer (thermosetting polyimide film)

[0033] The method for preparing a single-sided adhesive-free polyimide flexible copper-clad laminate in this embodiment is as follows:

[0034] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 1 are sequentially stacked together and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 200°C, the temperature of the lower pressing roller in contact with the protective layer is 360°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 25μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0035] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0036] Example 2

[0037] like Figure 1 As shown, a single-sided adhesive-free polyimide flexible copper-clad laminate of this embodiment is prepared with a laminated pressing structure, which is the same as Table 1 in Example 1.

[0038] The preparation method is as follows:

[0039] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 1 are sequentially stacked together and placed in a five-axis high-temperature press for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 280°C, the temperature of the lower pressing roller in contact with the protective layer is 360°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 25μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0040] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic dielectric layer was 280-300°C.

[0041] Example 3

[0042] like Figure 1 As shown in Table 2, a 50μm single-sided adhesive-free polyimide flexible copper clad laminate is prepared with a laminated structure as shown in Table 2:

[0043] Table 2 50μm single-sided adhesive-free polyimide flexible copper clad laminate high temperature hot pressing lamination

[0044]

[0045]

[0046] The preparation method is as follows:

[0047] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 2 are sequentially stacked together and placed in a five-axis high-temperature press for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 200°C, the temperature of the lower pressing roller in contact with the protective layer is 360°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 14Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of a 50μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling, and the structure is as follows Figure 3 shown.

[0048] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0049] Example 4

[0050] like Figure 2 As shown, in this embodiment 1, a single-sided adhesive-free polyimide flexible copper-clad laminate is prepared into a laminated structure, which includes, from top to bottom, a release layer 10, a layer of a polyimide composite film 20 with a thickness of 25 μm, a layer of a polyimide composite film 20 with a thickness of 50 μm, a copper foil layer 30, and a protective layer 40; the laminated structure is shown in Table 3:

[0051] Table 3 75μm single-sided adhesive-free polyimide flexible copper clad laminate high temperature hot pressing lamination

[0052]

[0053]

[0054] The preparation method is as follows:

[0055] The release layer, two-layer polyimide composite film, copper foil layer and protective layer of the specifications in Table 3 are stacked together in order, and placed in a five-axis high-temperature press for high-temperature roller hot pressing treatment. The conditions for high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 220°C, the temperature of the lower pressing roller in contact with the protective layer is 360°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 75μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0056] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0057] Example 5

[0058] like Figure 2 As shown, a 100 μm single-sided adhesive-free polyimide flexible copper-clad laminate is prepared with a laminated structure, which includes, from top to bottom, a release layer 10, two layers of polyimide composite films 20 with a thickness of 50 μm each, a copper foil layer 30, and a protective layer 40; the laminated structure is shown in Table 4:

[0059] Table 4 100μm single-sided adhesive-free polyimide flexible copper clad laminate high temperature hot pressing lamination

[0060] Serial number Material Tier 1 Release layer (thermosetting polyimide film) Tier 2 50μm polyimide composite film Tier 3 50μm polyimide composite film Layer 4 12μm copper foil layer Tier 5 Protective layer (thermosetting PI polyimide film)

[0061] The release layer, two-layer polyimide composite film, copper foil layer and protective layer of the specifications in Table 4 are sequentially stacked together and placed in a five-axis high-temperature press for high-temperature roller hot pressing treatment. The conditions for high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 280°C, the temperature of the lower pressing roller in contact with the protective layer is 320°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 75μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0062] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 280-300°C.

[0063] Comparative Example

[0064] Comparative Example 1

[0065] A coating method is used to prepare a polyimide copper-clad laminate. The difference between this comparative example 1 and Example 1 is that the comparative example uses the prepared polyimide prepolymer glue to be coated on a 12 μm copper foil, and then a 25 μm single-sided adhesive-free polyimide flexible copper-clad laminate having the same structure as Example 1 is prepared by baking the solvent and performing high-temperature cyclization in an IR furnace. Figure 3 shown.

[0066] Comparative Example 2

[0067] A laminated structure is prepared by a single-sided adhesive-free polyimide flexible copper-clad laminate, which is different from Example 1 in that the temperature of the hot pressing roller contacting the release layer in the high-temperature roller hot pressing treatment conditions in Comparative Example 2 is 300°C, which is higher than the hot pressing roller temperature of the release layer in the example.

[0068] The preparation method of a single-sided adhesive-free polyimide flexible copper-clad laminate in this comparative example is as follows:

[0069] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 1 are sequentially stacked together and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 300°C, the temperature of the lower pressing roller in contact with the protective layer is 360°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 25μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by winding. The structure is as follows Figure 3 shown.

[0070] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0071] Comparative Example 3

[0072] A laminated pressing structure is prepared by a single-sided adhesive-free polyimide flexible copper-clad laminate. The difference from Example 1 is that in Example 3, the temperature of the lower pressing wheel in contact with the protective layer under the conditions of high-temperature roller hot pressing treatment is 370°C, which is higher than the temperature of the lower pressing wheel in contact with the protective layer in the embodiment.

[0073] The preparation method of a single-sided adhesive-free polyimide flexible copper-clad laminate in this comparative example is as follows:

[0074] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 1 are sequentially stacked together and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 200°C, the temperature of the lower pressing roller in contact with the protective layer is 370°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 25μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0075] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0076] Comparative Example 4

[0077] A laminated pressing structure is prepared by a single-sided adhesive-free polyimide flexible copper-clad laminate, which is different from Example 1 in that the temperature of the lower pressing wheel in contact with the protective layer in the high-temperature roller hot pressing treatment in Comparative Example 3 is 320°C, which is lower than the temperature of the lower pressing wheel in contact with the protective layer in Example 1; the temperature of the upper pressing wheel in contact with the release layer is 300°C, which is higher than the temperature of the upper pressing wheel in contact with the release layer in Example 1.

[0078] The preparation method of a single-sided adhesive-free polyimide flexible copper-clad laminate in this comparative example is as follows:

[0079] The release layer, a layer of polyimide composite film, a copper foil layer and a protective layer of the specifications in Table 1 are sequentially stacked together and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment. The conditions for the high-temperature roller hot pressing treatment are: the temperature of the hot pressing roller in contact with the release layer is 300°C, the temperature of the lower pressing roller in contact with the protective layer is 320°C, the hot pressing speed is 1.0min, and the hot pressing pressure is 16Kg; after high-temperature pressing, a non-adhesive single-sided flexible copper-clad laminate with a release layer and a protective layer is obtained; and a roll of 25μm thick single-sided non-adhesive polyimide flexible copper-clad laminate is obtained by rolling. The structure is as follows Figure 3 shown.

[0080] The polyimide composite film was purchased from KANEKA and UBE, and the Tg temperature of the thermoplastic medium layer was 210-240°C.

[0081] Comparative Example 5

[0082] A coating method is used to prepare a polyimide copper-clad laminate. The difference between this comparative example 2 and Example 2 is that the comparative example uses the prepared polyimide prepolymer glue to be coated on a 12 μm copper foil, and then a 50 μm single-sided adhesive-free polyimide flexible copper-clad laminate having the same structure as Example 2 is prepared by baking the solvent and high-temperature cyclization in an IR furnace. Figure 4As shown in the figure, due to the severe shrinkage of polyimide during the preparation process, only sheet-shaped test samples can be prepared, and roll-shaped samples cannot be prepared.

[0083] Performance Testing:

[0084] The performance tests were conducted on the single-sided adhesive-free polyimide flexible copper clad laminates prepared in Examples 1 to 5 and Comparative Examples 1 to 5.

[0085] Test method:

[0086] The industry IPC-TM-650 testing method was used to test the warpage, peel strength, tensile strength, elongation, dimensional stability, thermal stress and other properties of the adhesive-free laminated flexible copper clad laminate materials prepared in the examples and comparative examples.

[0087] The test results are shown in Table 5.

[0088] Table 5 Copper clad laminate performance results

[0089]

[0090] According to Table 5, it can be seen that the warpage, peel strength, dimensional stability and heat resistance of the single-sided adhesive-free polyimide flexible copper-clad laminate prepared by the process of the present invention are significantly improved compared with the comparative example. From the test results of the embodiment and the comparative example, it can be seen that the combination of the lamination temperature affects the warpage, peel strength, dimensional stability and heat resistance of the single-sided adhesive-free polyimide flexible copper-clad laminate prepared by the process. As the lamination temperature of the release layer increases, the warpage of the single-sided adhesive-free polyimide flexible copper-clad laminate becomes larger. After exceeding the lamination temperature required by the invention, the warpage>2.0cm exceeds the industry standard. As the lamination temperature of the protective layer increases, the peel strength and dimensional stability of the single-sided adhesive-free polyimide flexible copper clad laminate increase. When the lamination temperature of the protective layer is lower than the temperature range required by the present invention, the single-sided adhesive-free polyimide flexible copper clad laminate has the problems of low peel strength and poor heat resistance. At the same time, when the lamination temperature of the protective layer is higher than the temperature range required by the present invention, the dimensional stability of the single-sided adhesive-free polyimide flexible copper clad laminate deteriorates and is close to the upper limit of ±0.1%.

Claims

1. A method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process, characterized in that The following steps are involved: The release layer, at least one layer of polyimide composite film, copper foil layer and protective layer are sequentially stacked together, and placed in a high-temperature roller pressing machine for high-temperature roller hot pressing treatment to obtain a non-adhesive single-sided flexible copper clad laminate with a release layer and a protective layer; The release layer is a thermosetting polyimide film; The polyimide composite film is a polyimide film with thermoplastic dielectric layers or thermoplastic polyimide layers on both sides; The conditions for high temperature roller hot pressing treatment are: The temperature of the hot pressing roller contacting the protective layer is 330-360° C., the temperature of the hot pressing roller contacting the release layer is 200-280° C., the hot pressing speed is 1.0-3.0 m / min, and the hot pressing pressure is 14-20 Kg.

2. The method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process according to claim 1, characterized in that The thickness of the polyimide composite film is 25-100 μm.

3. The method for preparing a simple and easy-to-use adhesive-free single-sided flexible copper-clad laminate according to claim 1, characterized in that The release layer has a thickness of 50 to 125 μm and a width of 10 to 20 mm wider than the polyimide composite film.

4. The method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process according to claim 1, characterized in that The copper foil layer has a copper tooth Rz value of 0.7 to 2.8 μm, a copper foil layer thickness of 9 to 35 μm, and a width 10 to 20 mm wider than the polyimide composite film.

5. The method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process according to claim 1, characterized in that The thermoplastic medium layer is made of thermoplastic medium, and the Tg temperature of the thermoplastic medium is 210-300°C.

6. The method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process according to claim 1, characterized in that The protective layer is a layer of copper foil or a thermosetting polyimide film.

7. The method for preparing a non-adhesive single-sided flexible copper-clad laminate with a simple process according to claim 1, characterized in that The method also includes rolling up the prepared adhesive-free single-sided flexible copper clad laminate with a release layer and a protective layer. During the rolling up, the rolling end independently rolls up the release layer, the adhesive-free single-sided flexible copper clad laminate and the protective layer.

Images