CN219523279U

CN219523279U - Flexible insulating substrate

Info

Publication number: CN219523279U
Application number: CN202320700418.8U
Authority: CN
Inventors: 付志强
Original assignee: Shengyi Technology Co Ltd
Current assignee: Shengyi Technology Co Ltd
Priority date: 2023-03-31
Filing date: 2023-03-31
Publication date: 2023-08-15
Anticipated expiration: 2033-03-31

Abstract

The utility model relates to the technical field of insulating substrates, and provides a flexible insulating substrate. The flexible insulating substrate comprises a first polyimide film layer, a second polyimide film layer and a plurality of polyimide combined layers which are laminated between the first polyimide film layer and the second polyimide film layer. The polyimide composite layer comprises a first thermoplastic polyimide layer, a first thermosetting polyimide layer, polyimide fiber cloth, a second thermosetting polyimide layer and a second thermoplastic polyimide layer which are sequentially compounded. The polyimide composite layer comprises polyimide fiber cloth, thermosetting polyimide layers and thermoplastic polyimide layers, wherein the thermosetting polyimide layers and the thermoplastic polyimide layers are positioned on two sides of the polyimide fiber cloth. Therefore, the polyimide composite layer is made of polyimide materials with flexible structures, so that the polyimide composite layer has better flexibility. The two sides of the polyimide combination layer are respectively protected by the first polyimide film layer and the second polyimide film layer, and then the insulating substrate with excellent flexibility can be obtained.

Description

Flexible insulating substrate

Technical Field

The utility model relates to the technical field of insulating substrates, in particular to a flexible insulating substrate.

Background

The flexible insulating substrate is a flexible insulating film, and is generally used as an insulating carrier of a circuit board. Flexible insulating substrates can be made of a single component, such as FR-4 (fiberglass board) materials, but simply reinforced with fiberglass boards, have high rigidity and brittleness, lack of toughness, often show hole edges or board edges whitened due to high brittleness during machining, and severe cracking and delamination phenomena occur, whereas pure PI (polyimide) film materials have less than ideal hardness due to excessive softness, no strength and rigidity.

At present, a flexible insulating substrate is also prepared by compounding a plurality of layers of materials. If one provides an insulating substrate of glass fiber cloth, the middle layer is reinforced by glass fiber cloth, the outer layer is prepared by adopting a film protection mode, and the glass fiber cloth and the film are bonded by adopting an acrylic acid or epoxy glue system. Although the toughness of the insulating substrate prepared by the method is improved to a certain extent compared with that of a common epoxy glass fiber board, the insulating substrate has room for improvement in terms of flexibility, temperature resistance and light weight.

Disclosure of Invention

Based on the above problems, the present utility model aims to provide a novel flexible insulating substrate, which has excellent flexibility and low product weight ratio, and is suitable for the use requirements of light weight and high heat resistance of aerospace and the like.

In order to achieve the above object, the present utility model provides a flexible insulating substrate, which includes a first polyimide film layer, a second polyimide film layer, and a plurality of polyimide composite layers laminated between the first polyimide film layer and the second polyimide film layer, wherein the polyimide composite layers include a first thermoplastic polyimide layer, a first thermosetting polyimide layer, a polyimide fiber cloth, a second thermosetting polyimide layer, and a second thermoplastic polyimide layer, which are sequentially compounded.

As one technical scheme of the utility model, the thickness of the polyimide fiber cloth is 30-200 mu m.

As an aspect of the present utility model, the thickness of the first polyimide film layer and the second polyimide film layer is 5 to 150 μm independently.

As an aspect of the present utility model, the thickness of the first thermoplastic polyimide layer and the second thermoplastic polyimide layer is 5 to 10 μm, respectively.

As an aspect of the present utility model, the thickness of the first thermosetting polyimide layer and the second thermosetting polyimide layer is 5 to 20 μm independently.

As one technical scheme of the utility model, a plurality of polyimide combination layers are provided, and the thickness of each polyimide combination layer is not completely the same.

The middle part of the flexible insulating substrate is provided with a plurality of polyimide combined layers, and the polyimide combined layers comprise polyimide fiber cloth, thermosetting polyimide layers and thermoplastic polyimide layers, wherein the thermosetting polyimide layers and the thermoplastic polyimide layers are positioned on two sides of the polyimide fiber cloth. Therefore, the polyimide composite layer is made of polyimide materials with flexible structures, so that the polyimide composite layer has better flexibility. The two sides of the polyimide combination layer are respectively protected by the first polyimide film layer and the second polyimide film layer, and then the insulating substrate with excellent flexibility can be obtained.

Drawings

Fig. 1 is a cross-sectional view of a first embodiment of a flexible insulating substrate of the present utility model.

Fig. 2 is a cross-sectional view of a second embodiment of the flexible insulating substrate of the present utility model.

Fig. 3 is a cross-sectional view of a third embodiment of the flexible insulating substrate of the present utility model.

Fig. 4 is a cross-sectional view of a fourth embodiment of the flexible insulating substrate of the present utility model.

DESCRIPTION OF SYMBOLS IN THE DRAWINGS

10-a first polyimide film layer; 30-a second polyimide film layer; a 50-polyimide combination layer; 51-polyimide fiber cloth; 53 a-a first thermosetting polyimide layer; 53 b-a second thermosetting polyimide layer; 55 a-a first thermoplastic polyimide layer; 55 b-a second thermoplastic polyimide layer.

Detailed Description

For better illustrating the objects, technical solutions and advantageous effects of the present utility model, the present utility model will be further described with reference to the accompanying drawings. It is to be noted, however, that the summary of the utility model, which is provided herein below, is provided as a further explanation of the utility model and is not intended to be limiting.

As shown in fig. 1 to 4, the flexible insulating substrate includes a first polyimide film layer 10, a second polyimide film layer 30, and a plurality of polyimide composite layers 50 laminated between the first polyimide film layer 10 and the second polyimide film layer 30. The polyimide composite layer 50 includes a first thermoplastic polyimide layer 55a, a first thermosetting polyimide layer 53a, a polyimide fiber cloth 51, a second thermosetting polyimide layer 53b, and a second thermoplastic polyimide layer 55b, which are sequentially compounded. The middle of the flexible insulating substrate is a plurality of polyimide composite layers 50. The polyimide composite layer 50 includes a polyimide fiber cloth 51, thermosetting polyimide layers and thermoplastic polyimide layers located at both sides of the polyimide fiber cloth 51. The polyimide composite layer 50 is entirely made of polyimide material having a flexible structure, and thus has superior flexibility. Both sides of the polyimide composite layer 50 are protected by the first polyimide film layer 10 and the second polyimide film layer 30, respectively, and thus an insulating substrate excellent in flexibility can be obtained.

The number of polyimide composite layers 50 may be one, as shown in fig. 1 to 2, or two or more, and if a number of polyimide composite layers are provided, it is preferable that the thickness of each polyimide composite layer 50 is not exactly the same, and if a number of polyimide composite layers are provided, a plurality of polyimide composite layers 50 are stacked in the vertical direction, as shown in fig. 3 to 4. The number of polyimide composite layers 50 can be designed according to the desired thickness of the flexible insulating substrate. The polyimide fiber cloth 51 in the polyimide composite layer 50 is formed by weaving polyimide fibers, and the polyimide fiber cloth 51 may have a one-layer structure woven by polyimide fibers or a composite multi-layer structure. The first thermosetting polyimide layer 53a and the second thermosetting polyimide layer 53b can be obtained by immersing the polyimide fiber cloth 51 in a thermosetting polyimide resin solution and then thermally imidizing. Since the first thermosetting polyimide layer 53a and the second thermosetting polyimide layer 53b are obtained by impregnating the polyimide fiber cloth 51 with a thermosetting polyimide resin solution and then thermally imidizing, in practice, a part of the thermosetting polyimide resin solution may infiltrate into the pores of the polyimide fiber cloth 51, so that a microscopic interfacial layer exists between the thermosetting polyimide layer and the polyimide fiber cloth, that is, a fusion layer formed by compounding the thermosetting polyimide resin and the polyimide fiber cloth 51. The first thermoplastic polyimide layer 55a and the second thermoplastic polyimide layer 55b may be obtained by impregnating a polyimide fiber cloth adhesive sheet impregnated with a thermosetting polyimide resin (i.e., the first thermosetting polyimide layer 53a + polyimide fiber cloth 51+ the second thermosetting polyimide layer 53 b) with a thermoplastic polyimide resin solution and then thermally imidizing. The first polyimide film layer 10, the second polyimide film layer 30 and the plurality of polyimide composite layers 50 can be laminated and then pressed at high temperature to obtain the flexible insulating substrate. The flexible insulating substrate may have a planar structure as shown in fig. 1 and 3, or a curved structure as shown in fig. 2 and 4, but the flexible insulating substrate is made of polyimide material with a flexible structure, so that the flexible insulating substrate has better flexibility, and the specific shape of the structure can be set according to practical requirements.

Further, the thickness of the polyimide fiber cloth 51 is 30 to 200 μm, and the thickness thereof means the total thickness of the polyimide fiber cloth 51, that is, the thickness of a one-layer structure or a composite multi-layer structure woven from polyimide fibers. The thickness of the polyimide fiber cloth 51 may be, but is not limited to, 30 μm, 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, 150 μm, 170 μm, 190 μm, 200 μm. The thicknesses of the first polyimide film layer 10 and the second polyimide film layer 30 are each independently 5 to 150 μm, and the thicknesses of the first polyimide film layer 10 and the second polyimide film layer 30 may be the same or different, and the thicknesses of the two may be each independently but not limited to 5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, 150 μm. The thicknesses of the first thermoplastic polyimide layer 55a and the second thermoplastic polyimide layer 55b are each independently 5 to 10 μm, and the thicknesses of the first thermoplastic polyimide layer 55a and the second thermoplastic polyimide layer 55b may be the same or different, and the thicknesses of both may be each independently but not limited to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm. The thicknesses of the first thermosetting polyimide layer 53a and the second thermosetting polyimide layer 53b are each independently 5 to 20 μm, and the thicknesses of the first thermosetting polyimide layer 53a and the second thermosetting polyimide layer 53b may be the same or different, and the thicknesses of both may be each independently but not limited to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm.

The process of preparing the flexible insulating substrate may include the following steps.

(1) And (3) soaking polyimide fiber cloth woven by polyimide fibers in a thermosetting polyimide resin solution, controlling the thickness through a gluing machine and a clamping shaft gap, and drying most of solvents to obtain the polyimide fiber cloth bonding sheet impregnated with thermosetting polyamide acid resin.

(2) And (3) soaking the polyimide fiber cloth bonding sheet impregnated with the thermosetting polyimide resin in the step (1) in a thermoplastic polyimide resin solution, controlling the thickness through a gluing machine and a clamping shaft gap, and drying most of solvents to obtain the polyimide fiber cloth bonding sheet with the outer layer impregnated with the thermoplastic polyimide resin and the inner layer impregnated with the thermosetting polyimide resin.

(3) And (3) carrying out high-temperature imidization baking oven on the polyimide fiber cloth bonding sheet with the outer layer impregnated with the thermoplastic polyimide resin and the inner layer impregnated with the thermosetting polyimide resin obtained in the step (2), and carrying out temperature programming imidization on the polyamic acid resin to form polyimide, thereby obtaining the polyimide composite layer.

(4) And (3) laminating one or more polyimide combined layers obtained in the step (3) together, and pressing the upper and lower outer surfaces of the polyimide combined layers with one polyimide film layer at high temperature to obtain the flexible insulating substrate.

Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the scope of the present utility model, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present utility model can be modified or substituted without departing from the spirit and scope of the technical solution of the present utility model.

Claims

1. The flexible insulating substrate is characterized by comprising a first polyimide film layer, a second polyimide film layer and a plurality of polyimide combined layers which are laminated between the first polyimide film layer and the second polyimide film layer, wherein the polyimide combined layers comprise a first thermoplastic polyimide layer, a first thermosetting polyimide layer, polyimide fiber cloth, a second thermosetting polyimide layer and a second thermoplastic polyimide layer which are sequentially compounded.

2. The flexible insulating substrate according to claim 1, wherein the polyimide fiber cloth has a thickness of 30 to 200 μm.

3. The flexible insulating substrate according to claim 1, wherein the thickness of the first polyimide film layer and the second polyimide film layer is each independently 5 to 150 μm.

4. The flexible insulating substrate according to claim 1, wherein the thickness of the first thermoplastic polyimide layer and the second thermoplastic polyimide layer are each independently 5 to 10 μm.

5. The flexible insulating substrate according to claim 1, wherein the thickness of the first thermosetting polyimide layer and the second thermosetting polyimide layer are each independently 5 to 20 μm.

6. The flexible insulating substrate according to claim 1, wherein the polyimide composite layers are plural, and the thickness of each of the polyimide composite layers is not exactly the same.