CN112356415A

CN112356415A - Preparation method of ultrathin PFA (Polytetrafluoroethylene) film for 5G flexible circuit board

Info

Publication number: CN112356415A
Application number: CN202010914338.3A
Authority: CN
Inventors: 卢和俊; 郭浩; 林剑耀
Original assignee: Suzhou Shallow Rice Technology Co ltd
Current assignee: Suzhou Shallow Rice Technology Co ltd
Priority date: 2020-09-03
Filing date: 2020-09-03
Publication date: 2021-02-12

Abstract

The invention relates to a preparation method of an ultrathin PFA film for a 5G flexible circuit board, which comprises the steps of feeding, heating, extrusion molding and storage, and has the advantages of simple preparation process, easy acquisition by adopting PFA plastic as a raw material, breakthrough of material blockage, adoption of a specially-made screw and die head design, thin thickness of an extruded film, reliability of a film product, adoption of a customized automatic thickness measuring computer to control a die head adjusting system, accurate and rapid thickness measurement, and immediate feedback to a computer to accurately control and adjust a die head bolt so as to finely adjust a die head gap, thereby adjusting the thickness deviation of the material and ensuring that the tolerance of the ultrathin film is within +/-5%.

Description

Preparation method of ultrathin PFA (Polytetrafluoroethylene) film for 5G flexible circuit board

Technical Field

The invention relates to the technical field of ultrathin films, in particular to a preparation method of an ultrathin PFA film for a 5G flexible circuit board.

Background

TPI (namely modified polyimide) films and LCP films are mainly adopted by the 5G flexible circuit board. The problem is that the indexes Dk and Df are not ideal enough when high-frequency signals are transmitted. Moreover, the supply of materials is mainly controlled abroad. The PFA film has incomparable Low Df and Low Df performance and high temperature resistance of 260 ℃ compared with other films. The Dk of the PFA film is 2.1 and the Df is 0.001 or less. The requirements of the 5G flexible circuit board on high-frequency and high-speed signal transmission are ensured.

Disclosure of Invention

Based on the technical defects, the invention provides the negative oxygen ion corrugated composite board, which solves the technical defects in the technical problems.

The invention relates to a preparation method of an ultrathin PFA film for a 5G flexible circuit board, which comprises an extruder and raw materials for film production, and further comprises the following steps:

1) feeding: the raw material adopts PFA plastic, and the PFA plastic is put into equipment for processing;

2) heating: rotating PFA plastic at a preset rotation rate, and heating while rotating to obtain a raw material melt;

3) and (3) extrusion molding: stirring and fully melting the raw material melt by a screw in an extruder, uniformly mixing, and finally extruding and molding through an extrusion port;

4) and (3) storing: and cooling the PFA film after extrusion molding, and rolling and storing.

Further, the surface of the screw is designed by adopting a mixing head, two ends of the screw are respectively provided with a spiral bulge, and the middle part of the screw is provided with a regular concave-convex block.

Furthermore, the extruder also comprises a die head consisting of an upper die and a lower die which can move, the extrusion opening consists of a space in the middle of the die head, the extrusion opening is a flow-shaped area with a decreasing cross section area, and the streamline shape at the tail end with the lowest flow is further enhanced by the variable lead angle in the space, so that the flow of the molten resin is stable and uniform in the whole die width.

Further, this changing lead angle is the guide angle, comprises the chamfer on the die head inner wall, the extrusion mouth includes material mouth basin, shaping basin and ejection of compact basin, material mouth basin communicates with each other with extruder raw materials fuse-element discharge gate, shaping basin and material mouth basin communicate with each other and the chamfer between be 150 degrees, ejection of compact basin and shaping basin communicate with each other and the chamfer between be 130 degrees.

The preparation method of the ultrathin PFA film for the 5G flexible circuit board is simple in preparation process, PFA plastic is used as a raw material, the obtaining is easy, the material blockage is broken through, the special screw and die head design is adopted, the thickness of the extruded film is thin, and the film product is reliable.

Drawings

FIG. 1 is a schematic diagram of the die structure of the present invention.

1. A die head; 2. an extrusion port.

Detailed Description

The invention will be further explained with reference to the drawings.

3) and (3) extrusion molding: stirring and fully melting the raw material melt by a screw in an extruder, uniformly mixing, and finally extruding and molding through an extrusion port 2;

Further, the extruder also comprises a die head 1 consisting of an upper die and a lower die which can move, the extrusion opening 2 consists of a space in the middle of the die head 1, the extrusion opening 2 is a flow-shaped area with a decreasing cross section area, and the streamline shape of the tail end with the lowest flow is further enhanced by the changing lead angle in the space, so that the flow of the molten resin is stable and uniform in the whole die width.

Further, this changing lead angle is the guide angle, comprises the chamfer on the die head 1 inner wall, extrusion mouth 2 includes material mouth watershed, shaping watershed and ejection of compact watershed, material mouth watershed and extruder raw materials fuse-element discharge gate communicate with each other, shaping watershed and material mouth watershed communicate with each other and the chamfer between be 150 degrees, ejection of compact watershed and shaping watershed communicate with each other and the chamfer between be 130 degrees.

The special screw design with the length-diameter ratio of 50:1 is adopted to ensure the sufficient melting of the materials in the extruder, the materials are uniformly mixed through the unique mixing head design, and the stable extrusion amount is ensured by the two-stage reduction gear reduction box.

According to the figure 1, the die head 1 is designed by adopting a flow transition angle based on resin hydrodynamics, a flow area with a decreasing cross section area is specially designed, the streamline shape of the tail end with the lowest flow is further enhanced by a variable guide angle, the flow of the molten resin of the whole die width is stable and uniform, especially an ultrathin film with high requirement, a customized automatic thickness measuring computer is adopted to control a die head 1 adjusting system, the thickness is accurately and rapidly measured and immediately fed back to the computer to accurately control and adjust a bolt of the die head 1, so that the gap of the die head 1 is finely adjusted, the thickness deviation of the material is adjusted, and the tolerance of the ultrathin film is ensured to be within +/-5%.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention relates, several simple deductions or substitutions may be made without departing from the spirit of the invention, and all shall be considered as belonging to the scope of the invention.

Claims

1. A preparation method of an ultrathin PFA film for a 5G flexible circuit board is characterized by comprising the following steps: comprising an extruder and raw materials for film production, further comprising the steps of:

2. The method for preparing the ultrathin PFA film for the 5G flexible circuit board according to claim 1, wherein the method comprises the following steps: the surface of the screw is designed by adopting a mixing head, two ends of the screw are respectively provided with a spiral bulge, and the middle part of the screw is provided with a regular concave-convex block.

3. The method for preparing the ultrathin PFA film for the 5G flexible circuit board according to claim 1, wherein the method comprises the following steps: the extruder also comprises a die head consisting of an upper die and a lower die which can move, the extrusion opening consists of a space in the middle of the die head, the extrusion opening is a flow-shaped area with a decreasing cross section area, and the streamline shape of the tail end with the lowest flow is further enhanced by the variable lead angle in the space, so that the flow of the molten resin in the whole die width is stable and uniform.

4. The method for preparing the ultrathin PFA film for the 5G flexible circuit board according to claim 3, wherein the method comprises the following steps: this changing lead angle is the guide angle, comprises the chamfer on the die head inner wall, the extrusion mouth includes material mouth watershed, shaping watershed and ejection of compact watershed, material mouth watershed communicates with each other with extruder raw materials fuse-element discharge gate, shaping watershed communicates with each other and the chamfer between and for 150 degrees with the material mouth watershed, ejection of compact watershed communicates with each other and the chamfer between and for 130 degrees with shaping watershed.