Polytetrafluoroethylene and metal composite material and preparation method thereof

Abstract

The invention provides a polytetrafluoroethylene and metal composite material and a preparation method thereof. The preparation method of the polytetrafluoroethylene and metal composite material comprises the following steps: cleaning a polytetrafluoroethylene film; performing an ion implantation process on the cleaned polytetrafluoroethylene film by using a metal ion source in a vacuum chamber of an ion implanter so as to form a metal seed layer on the surface of the polytetrafluoroethylene film; and performing metal plating on the polytetrafluoroethylene film with the metal seed layer formed on the surface to form a metal layer on the surface of the polytetrafluoroethylene film. The polytetrafluoroethylene and metal composite material prepared by the method has excellent gas barrier property and electromagnetic shielding property, so that the polytetrafluoroethylene and metal composite material has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a composite material of polytetrafluoroethylene and metal and a preparation method thereof. Background Art

[0002] Polytetrafluoroethylene has high chemical stability, thermal stability and excellent dielectric resistance. In addition, due to its unique structure, polytetrafluoroethylene also has excellent insulation and low dielectric constant, which makes polytetrafluoroethylene film materials widely used in many fields such as high-frequency and high-voltage cables and liquid crystal display production. However, the electronic structure of the fluorine atoms coated on the surface of carbon atoms in polytetrafluoroethylene is similar to that of inert gases, and the radius of fluorine atoms is small and difficult to be polarized, which makes the polymer molecular chains lack the necessary mutual binding force. This structural feature causes a large number of micropores to exist inside the polytetrafluoroethylene film material, and gases or small molecular compounds can leak along the micropores, making the polytetrafluoroethylene film material have a large permeability, so the application range of polytetrafluoroethylene film materials is limited.

[0003] For this reason, methods to improve the barrier properties of polytetrafluoroethylene film materials have always attracted much attention. One method is to use strong radiation to produce active groups in polytetrafluoroethylene so that reactions occur between polytetrafluoroethylene molecular chains. This method can improve the barrier properties of polytetrafluoroethylene film materials, but strong radiation will reduce the strength of polytetrafluoroethylene film materials. Composite high-barrier metal film on the surface of plastic film is an effective strategy to improve the barrier properties of film materials; in addition, polytetrafluoroethylene has excellent corrosion resistance and weather resistance; metal film can effectively prevent the penetration of electromagnetic waves, but its corrosion resistance and weather resistance are insufficient, so the two can be composited to obtain a corrosion-resistant and weather-resistant high-efficiency electromagnetic shielding coating material. However, due to the unique amphiphilicity of polytetrafluoroethylene, the metal film and polytetrafluoroethylene film material lack the necessary bonding force, which easily leads to layer peeling. At present, there is no process that can achieve effective composite between polytetrafluoroethylene and metal film. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preparing a composite material of polytetrafluoroethylene and metal. The method for preparing the composite material of polytetrafluoroethylene and metal comprises the following steps: cleaning a polytetrafluoroethylene film; performing an ion implantation process on the cleaned polytetrafluoroethylene film using a metal ion source in a vacuum chamber of an ion implanter to form a metal seed layer on the surface of the polytetrafluoroethylene film; performing a metal plating process on the polytetrafluoroethylene film with the metal seed layer formed on the surface to form a metal layer on the surface of the polytetrafluoroethylene film.

[0005] In a specific embodiment of the present invention, the polytetrafluoroethylene membrane is cleaned using an organic solvent or plasma, the organic solvent is one selected from ethanol, isopropanol, acetone and petroleum ether, the plasma is plasma air or vacuum plasma of an inert gas, and the inert gas includes nitrogen, argon and helium.

[0006] In a specific embodiment of the present invention, during the ion implantation process, the vacuum chamber is evacuated to 10 -5 -10 -3 The absolute pressure of Pa, the injection voltage is 10-40 kV, and the injection dose is 10 15 -10 17 ions / cm2.

[0007] In a specific embodiment of the present invention, the metal of the metal ion source includes nickel, cobalt, manganese, copper, aluminum, lead, gold, silver, platinum and palladium.

[0008] In a specific embodiment of the present invention, in the metal plating process, the metal includes copper, gold, silver, nickel, cobalt, manganese, lead, aluminum, zinc, iron, magnesium and titanium.

[0009] In a specific embodiment of the present invention, in the metal plating process, when the metal is copper, gold, silver, nickel, cobalt, manganese or lead, the metal plating is performed by electroplating, and when the metal is aluminum, zinc, iron, magnesium or titanium, the metal plating is performed by vacuum plating.

[0010] In a specific embodiment of the present invention, when the electroplating method is used, the electroplating voltage is 6-12 V, the electroplating speed is 0.3-0.5 m / min, and when the vacuum plating method is used, the speed is 0.15-0.2 m / min.

[0011] In a specific embodiment of the present invention, the metal of the metal seed layer and the metal of the metal layer are the same as or different from each other.

[0012] In addition, the present invention provides a composite material of polytetrafluoroethylene and metal prepared by the preparation method as described above.

[0013] In a specific embodiment of the present invention, the thickness of the metal layer in the composite material of polytetrafluoroethylene and metal is 2.4-4.5 μm.

[0014] In a specific embodiment of the present invention, the gas permeability of the composite material of polytetrafluoroethylene and metal is 0.01-0.03 g / m 2 (24 h, 0.1 MPa).

[0015] In addition, the present invention provides the use of the composite material of polytetrafluoroethylene and metal as described above in the preparation of a product with high gas barrier properties.

[0016] In addition, the present invention provides the use of the composite material of polytetrafluoroethylene and metal as described above in the preparation of electromagnetic shielding products.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The composite method of polytetrafluoroethylene and metal of the present invention can improve the barrier property without changing the chemical and physical properties of the polytetrafluoroethylene film, thereby avoiding the problem of reduced mechanical strength of the polytetrafluoroethylene film when cross-linking by strong radiation.

[0018] The method of the present invention forms a metal layer on the surface of polytetrafluoroethylene by ion implantation and coating, so that the polytetrafluoroethylene and the metal layer have extremely high adhesion, thereby overcoming the technical difficulty that polytetrafluoroethylene is difficult to composite due to its amphiphobic properties, and a composite material of polytetrafluoroethylene and metal can be prepared at a relatively low cost.

[0019] The composite material of polytetrafluoroethylene and metal prepared by the method of the present invention has excellent gas barrier properties and electromagnetic shielding properties, and therefore has good application prospects.

[0020] Ion implantation and vacuum coating are both vacuum technologies, which are clean and pollution-free. The films produced by these technologies are highly crystalline and meet the requirements of the electrical conductor industry. DETAILED DESCRIPTION

[0021] The present invention aims to solve the problem that the polytetrafluoroethylene film material has micropores in its structure due to weak interaction between molecular chains, thereby having poor barrier properties to gases and small molecular compounds. To this end, the present invention uses an ion implantation process to form a metal seed layer on the surface of the polytetrafluoroethylene film, and then grows a metal layer on its surface by vacuum plating or electroplating, thereby achieving effective composite of polytetrafluoroethylene and metal.

[0022] Ion implantation is a technique that uses a high voltage electric field to accelerate gas and metal ions, causing them to directly bombard the surface of a material and form a third phase on the surface of the material, thereby achieving material modification. Metal ions are injected into the surface of polytetrafluoroethylene to form a seed layer, and then a metal film can be directly formed on the surface of the polytetrafluoroethylene film material by vacuum plating or electroplating. This method of directly growing a metal film on the surface of polytetrafluoroethylene significantly enhances the adhesion between polytetrafluoroethylene and the metal film, and by composite metal layers on the surface of polytetrafluoroethylene, not only can the strength and other mechanical properties of polytetrafluoroethylene be retained, but also extremely strong barrier properties can be given to it. Therefore, the composite material of polytetrafluoroethylene and metal obtained by the method of the present invention has extremely low permeability, and therefore has excellent gas barrier properties, and the metal layer can also shield electromagnetic signals, and therefore has excellent electromagnetic shielding properties.

[0023] Specifically, the present invention adopts the following technical solutions: 1. Before ion implantation, the polytetrafluoroethylene membrane is cleaned with an organic solvent (for example, one of the organic solvents such as ethanol, isopropanol, acetone, petroleum ether, etc.), and then dried at 80-120°C after cleaning; or the polytetrafluoroethylene membrane can be cleaned with plasma, and the commonly used plasma is plasma air plasma or vacuum plasma of inert gases such as nitrogen, argon and helium.

[0024] 2. Place the cleaned PTFE membrane into the vacuum chamber of the ion implanter and turn on the vacuum system to evacuate to 10 -5 -10 -3 Pa absolute pressure (preferably 10 -5 Pa absolute pressure), and then turn on the ion source for ion implantation. The metals of the metal ion source include nickel, cobalt, manganese, copper, aluminum, lead, gold, silver, platinum and palladium, etc. The injection intensity voltage is 10-40 kV (preferably 15-30 kV, more preferably 20-30 kV), and the injection dose is controlled to be 10 15 -10 17 ions / cm2. After the ion implantation, the ion source and vacuum system were turned off, and the ion-implanted modified polytetrafluoroethylene membrane was taken out from the vacuum chamber.

[0025] 3. If you want to achieve the composite of metals with high oxidation potential and polytetrafluoroethylene film, such as copper, gold, silver, nickel, cobalt, manganese, lead and other metals, the electroplating method is generally used: the polytetrafluoroethylene film is passed through an electrolytic cell with metal salts, and the electrodes are clamped on the polytetrafluoroethylene film for electroplating. The metal of the electroplated film can be the same as the metal ions of the seed layer, or it can be different from the metal ions of the seed layer formed by ion implantation.

[0026] 4. If you want to realize the composite of metals with low oxidation potential and polytetrafluoroethylene film, such as aluminum, zinc, iron, magnesium, titanium and other metals, the vacuum plating method is generally used: put the polytetrafluoroethylene film into the vacuum chamber of the vacuum coating machine and directly perform vacuum coating. The metal of the coating can be the same as the metal ions of the seed layer, or it can be different from the metal ions of the seed layer formed by ion implantation.

[0027] 5. After coating treatment, a composite film of polytetrafluoroethylene and metal can be obtained. Under the action of the seed layer, there is no obvious connection between the metal layer and the polytetrafluoroethylene, and it has high adhesion, so it will not peel off during use.

[0028] As described above, the composite material of polytetrafluoroethylene and metal of the present invention has excellent barrier properties, and thus can be used to prepare high-barrier products, such as high-barrier airbags, surface layers of aircraft skins, and the like.

[0029] As described above, the composite material of polytetrafluoroethylene and metal of the present invention has excellent electromagnetic shielding properties, and thus can be used to prepare highly weather-resistant electromagnetic shielding products.

[0030] Below, the preferred embodiments of the present invention will be described in detail in conjunction with specific embodiments. It should be understood that the following embodiments are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0032] Example 1: Production of polytetrafluoroethylene aluminum composite membrane using nickel ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use nitrogen as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal nickel target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4 Pa, ion implantation was performed, the implantation voltage was 30 kV, the extraction current during the implantation process was 15 mA, the film travel speed was 0.2 m / min, and after the implantation was completed, the vacuum system was turned off and the sample was taken out. The ion-implanted film was placed in the vacuum chamber of the vacuum coating machine and coated at a travel speed of 0.15 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the aluminum layer formed on the polytetrafluoroethylene film was 3.2 μm. The polytetrafluoroethylene film before and after modification was analyzed using the water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.15 g / m 2(24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the aluminum layer was grown on the surface was 0.03 g / m 2 (24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the aluminum layer is grown on the surface against 300M and 1000M electromagnetic waves is 89% and 88.4%.

[0033] Example 2: Production of polytetrafluoroethylene copper composite membrane using nickel ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use nitrogen as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal nickel target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4 Pa, ion implantation was performed, the implantation voltage was 30 kV, the extraction current during the implantation process was 14 mA, the membrane travel speed was 0.2 m / min, and the vacuum system was turned off and the sample was taken out after the implantation. The ion-implanted membrane was placed in an electroplating tank and plated, the electroplating voltage was 12 V, and the electroplating travel speed was 0.3 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the copper layer formed on the polytetrafluoroethylene film was 4.5 μm. The polytetrafluoroethylene film before and after modification was analyzed by water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.15 g / m 2 (24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the copper layer was grown on the surface was 0.01 g / m 2 (24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the copper layer is grown on the surface against 300M and 1000M electromagnetic waves is 88% and 86%.

[0034] Example 3: Production of polytetrafluoroethylene aluminum composite membrane using iron ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use argon as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal iron target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4Pa, ion implantation was performed, the injection voltage was 30 kV, the extraction current during the injection process was 12 mA, the film travel speed was 0.3 m / min, and after the injection was completed, the vacuum system was turned off and the sample was taken out. The ion-implanted film was placed in the vacuum chamber of the vacuum coating machine and coated at a travel speed of 0.2 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the aluminum layer formed on the polytetrafluoroethylene film was 2.5 μm. The polytetrafluoroethylene film before and after modification was analyzed by the water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.15 g / m 2 (24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the aluminum layer was grown on the surface was 0.02 g / m 2 (24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the aluminum layer is grown on the surface against 300M and 1000M electromagnetic waves is 87% and 85.7%.

[0035] Example 4: Production of polytetrafluoroethylene zinc composite film using nickel ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use nitrogen as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal nickel target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4 Pa, ion implantation was performed, the implantation voltage was 30 kV, the extraction current during the implantation process was 14 mA, the membrane travel speed was 0.2 m / min, and the vacuum system was turned off and the sample was taken out after the implantation. The ion-implanted membrane was placed in an electroplating tank and plated, the electroplating voltage was 6 V, and the electroplating travel speed was 0.3 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the zinc layer formed on the polytetrafluoroethylene film was 3.4 μm. The polytetrafluoroethylene film before and after modification was analyzed by water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.15 g / m 2 (24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the zinc layer was grown on the surface was 0.015 g / m 2 (24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the zinc layer is grown on the surface against 300M and 1000M electromagnetic waves is 88.7% and 86.7%.

[0036] Example 5: Production of polytetrafluoroethylene aluminum composite membrane using aluminum ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use nitrogen as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal aluminum target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4 Pa, ion implantation was performed, the implantation voltage was 30 kV, the extraction current during the implantation process was 12 mA, the film travel speed was 0.3 m / min, and after the implantation was completed, the vacuum system was turned off and the sample was taken out. The ion-implanted film was placed in the vacuum chamber of the vacuum coating machine and coated at a travel speed of 0.2 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the aluminum layer formed on the polytetrafluoroethylene film was 2.5 μm. The polytetrafluoroethylene film before and after modification was analyzed using the water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.21 g / m 2 (24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the aluminum layer was grown on the surface was 0.03 g / m 2 (24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the aluminum layer is grown on the surface against 300M and 1000M electromagnetic waves is 87.3% and 86.8%.

[0037] Example 6: Production of polytetrafluoroethylene aluminum composite membrane using lead ion implantation Take a roll of polytetrafluoroethylene film casting and put it into a plasma cleaning machine. Use nitrogen as the cleaning source and perform plasma cleaning at an absolute pressure of 1-100 Pa. Put a metal lead target in the ion implanter, transfer the polytetrafluoroethylene film to the vacuum chamber of the ion implanter, and evacuate to 4×10 -4 Pa, ion implantation was performed, the implantation voltage was 25 kV, the extraction current during the implantation process was 14 mA, the film travel speed was 0.2 m / min, and after the implantation was completed, the vacuum system was turned off and the sample was taken out. The ion-implanted film was placed in the vacuum chamber of the vacuum coating machine and coated at a travel speed of 0.2 m / min. After the coating was completed, the film thickness was analyzed, and it was found that the thickness of the aluminum layer formed on the polytetrafluoroethylene film was 2.4 μm. The polytetrafluoroethylene film before and after modification was analyzed using the water vapor permeability test. The water vapor permeability of the polytetrafluoroethylene film before modification was 1.22 g / m 2 (24 h, 0.1 MPa), the water vapor permeability of the polytetrafluoroethylene film after the aluminum layer was grown on the surface was 0.03 g / m 2(24 h, 0.1 MPa). In addition, the electromagnetic wave shielding performance test results show that the shielding effectiveness of the polytetrafluoroethylene film after the aluminum layer is grown on the surface against 300M and 1000M electromagnetic waves is 86.4% and 85.4%.

[0038] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for preparing a composite material of polytetrafluoroethylene and metal, characterized in that: The following steps are involved: Cleaning the polytetrafluoroethylene membrane; In a vacuum chamber of an ion implanter, an ion implantation process is performed on the cleaned polytetrafluoroethylene film using a metal ion source to form a metal seed layer on the surface of the polytetrafluoroethylene film; The polytetrafluoroethylene film having the metal seed layer formed on the surface thereof is subjected to a metal plating process to form a metal layer on the surface of the polytetrafluoroethylene film.

2. The method for preparing a composite material of polytetrafluoroethylene and metal according to claim 1, characterized in that: The polytetrafluoroethylene film is cleaned by using an organic solvent or plasma, wherein the organic solvent is one selected from ethanol, isopropanol, acetone and petroleum ether, and the plasma is plasma air or vacuum plasma of an inert gas, wherein the inert gas includes nitrogen, argon and helium.

3. The method for preparing the composite material of polytetrafluoroethylene and metal according to claim 1, characterized in that: In the ion implantation process, the vacuum chamber is evacuated to 10 -5 -10 -3 The absolute pressure of Pa, the injection voltage is 10-40 kV, and the injection dose is 10 15 -10 17 ions / cm2.

4. The method for preparing a composite material of polytetrafluoroethylene and metal according to claim 1, characterized in that: The metals of the metal ion source include nickel, cobalt, manganese, copper, aluminum, lead, gold, silver, platinum and palladium.

5. The method for preparing a composite material of polytetrafluoroethylene and metal according to claim 1, characterized in that: In the metal plating process, the metals include copper, gold, silver, nickel, cobalt, manganese, lead, aluminum, zinc, iron, magnesium and titanium.

6. The method for preparing the composite material of polytetrafluoroethylene and metal according to claim 5, characterized in that: In the metal plating process, when the metal is copper, gold, silver, nickel, cobalt, manganese or lead, the metal plating is performed using an electroplating method, and when the metal is aluminum, zinc, iron, magnesium or titanium, the metal plating is performed using a vacuum plating method.

7. The method for preparing a composite material of polytetrafluoroethylene and metal according to claim 6, characterized in that: When the electroplating method is used, the electroplating voltage is 6-12 V, and the electroplating travel speed is 0.3-0.5 m / min. When the vacuum plating method is used, the travel speed is 0.15-0.2 m / min.

8. The method for preparing a composite material of polytetrafluoroethylene and metal according to claim 1, characterized in that: The metal of the metal seed layer and the metal of the metal layer may be the same as or different from each other.

9. A composite material of polytetrafluoroethylene and metal, prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the composite material of polytetrafluoroethylene and metal according to claim 9 in preparing products with high gas barrier properties.

11. Use of the composite material of polytetrafluoroethylene and metal according to claim 9 in the preparation of electromagnetic shielding products.