阅读说明：本技术 Ptfe复合材料薄片的制备方法、ptfe复合材料薄片及应用该薄片的覆铜板 (Preparation method of PTFE composite material sheet, PTFE composite material sheet and copper-clad plate using PTFE composite material sheet ) 是由 邹水平 王琢 钟健人 于 2020-06-24 设计创作，主要内容包括：本发明公开了一种PTFE复合材料薄片的制备方法,包括以下步骤：S1：将悬浮聚四氟乙烯和陶瓷粉料加入到混料设备中,所述混料设备包括圆柱形的混料桶、设置在混料桶底且能够水平旋转的大桨叶和设置在混料桶内侧壁且能够在竖直平面上旋转的小桨叶,所述大桨叶最末端的线速度为6.0-6.5m/min,所述小桨叶最末端的线速度为1.5-2.0m/min所述混料桶的直径为50cm,深度为45cm,搅拌时间至少为1min；S2：将混合所得的混合料加入到模具中,压制得到毛坯；S3：对毛坯烧结,得到复合材料；S4：将所得复合材料切削成PTFE复合材料薄片。大桨叶与小桨叶以本公开提供的速度配合旋转,使得陶瓷粉和PTFE充分混合。本发明还公开了由上述方法制备而成的PTFE复合材料薄片以及应用该PTFE复合材料薄片的覆铜板。(The invention discloses a preparation method of a PTFE composite material sheet, which comprises the following steps: s1: adding suspended polytetrafluoroethylene and ceramic powder into a mixing device, wherein the mixing device comprises a cylindrical mixing barrel, a large blade which is arranged at the bottom of the mixing barrel and can rotate horizontally, and a small blade which is arranged on the inner side wall of the mixing barrel and can rotate on a vertical plane, the linear velocity of the tail end of the large blade is 6.0-6.5m/min, the linear velocity of the tail end of the small blade is 1.5-2.0m/min, the diameter of the mixing barrel is 50cm, the depth of the mixing barrel is 45cm, and the stirring time is at least 1 min; s2: adding the mixed material into a die, and pressing to obtain a blank; s3: sintering the blank to obtain a composite material; s4: the resulting composite was cut into PTFE composite sheets. The large paddle and the small paddle rotate cooperatively at the speed provided by the present disclosure, so that the ceramic powder and the PTFE are mixed sufficiently. The invention also discloses the PTFE composite material sheet prepared by the method and a copper-clad plate using the PTFE composite material sheet.)

A preparation method of a PTFE composite material sheet is characterized by comprising the following steps:

s1: adding suspended polytetrafluoroethylene and ceramic powder into a mixing device, wherein the mixing device comprises a cylindrical mixing barrel, a large blade which is arranged at the bottom of the mixing barrel and can rotate horizontally, and a small blade which is arranged on the inner side wall of the mixing barrel and can rotate on a vertical plane, the linear velocity of the tail end of the large blade is 6.0-6.5m/min, the linear velocity of the tail end of the small blade is 1.5-2.0m/min, the radial distance between the tail end of the large blade and the inner wall of the mixing barrel is not more than 5cm, and the stirring time is at least 1 min;

s2: adding the mixed material into a die, and pressing to obtain a blank;

S3: sintering the blank to obtain a composite material;

s4: the resulting composite was cut into PTFE composite sheets.

2. The method of making a PTFE composite sheet of claim 1, wherein said large paddle comprises three large blades, said large paddle being disposed on a first shaft, said first shaft being driven to rotate by a first motor, said large blades rotating against an inner bottom surface of said mixing bowl.

3. The method of making a PTFE composite sheet of claim 1, wherein said paddle comprises three paddles, said paddle being disposed on a second shaft, said second shaft being driven for rotation by a second motor, said second shaft extending radially along said mixing bowl.

4. The method of preparing a PTFE composite sheet according to claim 1, wherein both the large and small paddles rotate simultaneously in a clockwise direction or simultaneously in a counterclockwise direction as viewed from the front of the large and small paddles.

5. The method of preparing a PTFE composite sheet according to claim 1, wherein the suspended polytetrafluoroethylene has a particle size of not more than 200 μm, a molecular weight of 100 to 800 ten thousand, the ceramic powder is silica, and the ceramic powder has a particle size of not more than 30 μm.

6. The method of claim 1, wherein the PTFE composite sheet comprises 40 to 60 parts by weight of the PTFE and 40 to 60 parts by weight of the ceramic powder.

7. The method of making a PTFE composite sheet of claim 6, wherein the mixture further comprises 0-2 parts of a coupling agent.

8. The method for preparing a PTFE composite sheet according to claim 1, wherein in step S2, the PTFE composite sheet is pressed in 5 stages, and the pressure of the former stage is completely released and then the latter stage is performed, and the pressure applied by the first stage is 5MPa and the dwell time is 5 min; the pressure applied by the second stage of pressing is 10MPa, and the pressure maintaining time is 5 min; the pressure applied by the third stage of pressing is 15MPa, and the pressure maintaining time is 5 min; the pressure applied by the fourth stage of pressing is 20MPa, and the pressure maintaining time is 5 min; the pressure applied in the fifth stage of pressing is 30MPa, and the dwell time is 220 min.

A PTFE composite sheet produced by the method for producing a PTFE composite sheet according to any one of claims 1 to 8.

10. The copper-clad plate using the PTFE composite material sheet of claim 9, which is characterized by comprising the PTFE composite material sheet of claim 9, wherein copper foils are adhered to two sides of the PTFE composite material sheet.

Technical Field

The invention relates to the field of copper-clad plates, in particular to a preparation method of a PTFE composite material sheet, the PTFE composite material sheet and a copper-clad plate applying the sheet.

Background

With the wide application of the 5G technology, the industry has higher and higher requirements for dielectric materials and copper-clad plates. The copper-clad plate comprises a dielectric material sheet and copper foils attached to two sides of the dielectric material sheet. Polytetrafluoroethylene (PTFE) has excellent dielectric properties, chemical resistance, heat resistance, flame retardancy, low dielectric constant and dielectric loss and low variation in a high frequency range, and is very suitable for dielectric materials. In general, composite dielectric materials prepared by filling PTFE with ceramic powder have more excellent performance. The forming steps of the PTFE composite material sheet comprise mixing, pressing, sintering and cutting. The mixing is a process of adding ceramic powder and PTFE into mixing equipment according to a certain proportion and stirring. Whether the mixed material is uniform or not is related to the distribution uniformity of the ceramic powder in the PTFE, and further the dielectric constant (D) of the PTFE composite material sheet and the copper-clad plate is influenced_k) Dielectric loss (D)_f) Uniformity of properties such as water absorption, Coefficient of Thermal Expansion (CTE), etc.

Disclosure of Invention

In order to uniformly mix ceramic powder and PTFE to obtain a PTFE composite sheet with consistent performance, the invention provides a preparation method of the PTFE composite sheet, which comprises the following steps:

S1: adding suspended polytetrafluoroethylene and ceramic powder into a mixing device, wherein the mixing device comprises a cylindrical mixing barrel, a large blade which is arranged at the bottom of the mixing barrel and can rotate horizontally, and a small blade which is arranged on the inner side wall of the mixing barrel and can rotate on a vertical plane, the linear velocity of the tail end of the large blade is 6.0-6.5m/min, the linear velocity of the tail end of the small blade is 1.5-2.0m/min, the radial distance between the tail end of the large blade and the inner wall of the mixing barrel is not more than 5cm, and the stirring time is at least 1 min;

s2: adding the mixed material into a die, and pressing to obtain a blank;

s3: sintering the blank to obtain a composite material;

s4: the resulting composite was cut into PTFE composite sheets.

The beneficial effects of the embodiment are as follows: big paddle rotates on the horizontal plane, stirs ceramic powder and PTFE, is the main power that ceramic powder and PTFE moved, in addition, this embodiment carries out supplementary stirring through little paddle for ceramic powder and PTFE intensive mixing.

In some embodiments, the large paddle comprises three large blades, the large blades are arranged on a first rotating shaft, the first rotating shaft is driven by a first motor to rotate, and the large blades rotate along the inner bottom surface of the mixing barrel.

In some embodiments, the small blades comprise a second rotating shaft and three small blades arranged on the periphery of the second rotating shaft, the second rotating shaft is driven by a second motor to rotate, and the second rotating shaft extends along the radial direction of the mixing barrel.

In certain embodiments, the large and small paddles both rotate in a clockwise direction simultaneously, or in a counter-clockwise direction simultaneously, as viewed from the front of the large and small paddles.

In certain embodiments, the suspended polytetrafluoroethylene has a particle size of no more than 200 μm, a molecular weight of 100 to 800 ten thousand, the ceramic powder is silica, and the ceramic powder has a particle size of no more than 30 μm.

In certain embodiments, the polytetrafluoroethylene is present in an amount of 40 to 60 parts by weight, and the ceramic powder is present in an amount of 40 to 60 parts by weight.

In certain embodiments, the compound further comprises 0-2 parts of a coupling agent.

In some embodiments, in step S2, the pressing is performed in 5 stages, and the pressure of the former stage is completely released and then the latter stage is performed, the pressure applied in the first stage is 5MPa, and the pressure holding time is 5 min; the pressure applied by the second stage of pressing is 10MPa, and the pressure maintaining time is 5 min; the pressure applied by the third stage of pressing is 15MPa, and the pressure maintaining time is 5 min; the pressure applied by the fourth stage of pressing is 20MPa, and the pressure maintaining time is 5 min; the pressure applied in the fifth stage of pressing is 30MPa, and the dwell time is 220 min. In the embodiment, a multiple-stage pressing method is adopted, so that the gas in the powder is fully released, and sintering cracks caused by gas expansion in gas holes in sintering are prevented.

According to another aspect of the present invention, there is provided a PTFE composite sheet produced by the above method for producing a PTFE composite sheet.

According to another aspect of the invention, a copper-clad plate is provided, which comprises the PTFE composite material sheet, wherein copper foils are adhered to two sides of the PTFE composite material sheet.

Drawings

Fig. 1 is a schematic view of a mixing device used in a method for preparing a PTFE composite sheet according to an embodiment of the present disclosure.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 schematically shows a schematic diagram of a mixing apparatus used in a method for producing a PTFE composite sheet according to an embodiment of the present disclosure.

A preparation method of a PTFE composite material sheet comprises the following steps:

s1: adding suspended polytetrafluoroethylene and ceramic powder into a mixing device, wherein the mixing device comprises a cylindrical mixing barrel, a large blade which is arranged at the bottom of the mixing barrel and can rotate horizontally, and a small blade which is arranged on the inner side wall of the mixing barrel and can rotate on a vertical plane, the linear velocity of the tail end of the large blade is 6.0-6.5m/min, the linear velocity of the tail end of the small blade is 1.5-2.0m/min, the diameter of the mixing barrel is 50cm, the depth of the mixing barrel is 45cm, and the stirring time is at least 1 min;

S2: adding the mixed material into a die, and pressing to obtain a blank;

s3: sintering the blank to obtain a composite material;

s4: the resulting composite was cut into PTFE composite sheets.

Big paddle 2 rotates on the horizontal plane, stirs ceramic powder and PTFE, is the main power that ceramic powder and PTFE moved, in addition, this embodiment carries out supplementary stirring through little paddle 3, the rotational speed of big paddle 2 that this embodiment provided, little paddle 3 rotational speed and big paddle are the best compounding parameter to compounding bucket inner wall radial distance isoparametric, can fully stir ceramic powder and PTFE, make ceramic powder and PTFE intensive mixing, and prevented the gathering of ceramic powder and PTFE.

In some embodiments, the large blade 2 comprises three large blades, the large blade 2 is arranged on a first rotating shaft 4, the first rotating shaft 4 is driven by a first motor 5 to rotate, and the large blade rotates along the inner bottom surface of the mixing barrel 1. The rotation of the blade can stir the lower-layer ceramic powder and PTFE, and the upper-layer powder is driven to move through the friction force between the powder. The blade pastes the interior bottom surface of compounding bucket 1, the reducible dead angle of stirring.

In some embodiments, the small blade 3 comprises three small blades, the small blade 3 is arranged on a second rotating shaft 6, the second rotating shaft 6 is driven by a second motor 7 to rotate, and the second rotating shaft 6 extends along the radial direction of the mixing barrel 1. The small blade 3 plays a role in auxiliary stirring and is matched with the large blade 2, so that the mixing is more sufficient. When viewed from the front of the large blade 2 and the small blade 3, both the large blade 2 and the small blade 3 rotate clockwise or counterclockwise simultaneously. Specifically, as shown in fig. 1, the arrow indicates the rotation direction of the large blade 2 and the small blade 3, the large blade 2 is clockwise when the large blade 2 is viewed in plan, and the small blade 3 is clockwise when the small blade 3 is viewed from the inner side of the mixing tub 1 in the radial direction. Alternatively, in some embodiments, the large blade 2 is counterclockwise when viewed from above, and the small blade 3 is counterclockwise when viewed from the inner side of the mixing bowl 1 in the radial direction, and the small blade 3 is counterclockwise. This has the advantage of creating greater turbulence in the mix, which results in more thorough mixing.

In certain embodiments, the suspended polytetrafluoroethylene has a particle size of no more than 200 μm and a molecular weight of 100 to 800 ten thousand. The polytetrafluoroethylene resin with the molecular weight range has better film forming property and processability.

In certain embodiments, the ceramic powder is silica and the ceramic powder has a particle size of no more than 30 μm. The particle size filler and the suspended polytetrafluoroethylene resin within 200 mu m have better dispersibility, and are beneficial to uniform mixing.

In certain embodiments, the polytetrafluoroethylene is present in an amount of 40 to 60 parts by weight, and the ceramic powder is present in an amount of 40 to 60 parts by weight.

In certain embodiments, the compound further comprises 0-2 parts of a coupling agent.

In some embodiments, in step S2, the pressing is performed in 5 stages, and the pressure of the former stage is completely released and then the latter stage is performed, the pressure applied in the first stage is 5MPa, and the pressure holding time is 5 min; the pressure applied by the second stage of pressing is 10MPa, and the pressure maintaining time is 5 min; the pressure applied by the third stage of pressing is 15MPa, and the pressure maintaining time is 5 min; the pressure applied by the fourth stage of pressing is 20MPa, and the pressure maintaining time is 5 min; the pressure applied in the fifth stage of pressing is 30MPa, and the dwell time is 220 min. In the embodiment, a multiple-stage pressing method is adopted, so that the gas in the powder is fully released, and sintering cracks caused by gas expansion in gas holes in sintering are prevented.

A PTFE composite material sheet is prepared by the preparation method of the PTFE composite material sheet.

A copper-clad plate comprises the PTFE composite material sheet, and copper foils are attached to two sides of the PTFE composite material sheet.